Filippo Giannetti's Scientific Publications

BOOKS AND CHAPTERS OF BOOKS

[B1] F. Giannetti, "Capacity of a CDMA Cellular System Operating in the 63-64 GHz-Band", in A. Pratelli, F. Fantozzi and R. Roncella eds., "La Ricerca e i Ricercatori della Facolta' di Ingegneria", published by Tipografia Editrice Pisana, Pisa, Italy, February 1995, pp. 565-582.

In this paper, the capacity of a cellular Code-Division Multiple Access (CDMA) system operating in the 63-64 GHz band, expressed as the number of users per cell, is evaluated. A propagation model for the 63-64 GHz band is first introduced and discussed. The system capacity is then analytically derived and compared with other CDMA schemes operating in conventional frequency bands (i.e. below 2 GHz). Finally, power requirements are derived and the impact of atmospheric conditions is evaluated. It turns out that the use of 63-64 GHz band greatly increases the capacity of asynchronous CDMA (A-CDMA) systems, and reveals suitable for cellular and personal communication networks (PCNs).

[B2] L. Fanucci, F. Giannetti, M. Luise, M. Rovini, "An Experimental Approach to CDMA and Interference Mitigation - From System Architecture to Hardware Testing through VLSI Design", Kluwer Academic Publishers, Boston, ISBN 1-4020-7723-8, February 2004. This book is available at Kluwer and Amazon .

The key of a successful approach to the complex issue of designing wireless terminals for present and future communication systems (usually addressed to as '3rd Generation and beyond') lies in a single 'magic' word: multidisciplinarity. This was actually the philosophy which inspired and drove a fruitful teamwork performed at the University of Pisa (Italy) under the auspices of the European Space Agency (ESA) with the goal of developing a digital receiver for CDMA mobile communications. The most challenging issue of the project was the implementation into a single ASIC device of an advanced detector for multi-user CDMA signals featuring interference mitigation capability. The whole design process, starting from system specifications down to final hardware testing, required quite a demanding and synergic effort, involving telecom engineers on one side and electronic designers on the other. The development and the achievements of the project gave the authors the cue for writing this book whose contents represents the lesson learnt from such an interdisciplinary research activity. An Experimental Approach to CDMA and Interference Mitigation was written with the admittedly ambitious intent of filling the gap between communication theory and VLSI implementation, and thus to provide a more general/theoretical approach to the design, development, and testing of a CDMA receiver. As a consequence, the concepts and techniques that are presented turn out to be applicable to a more general kind of digital wireless modems in terms of receiver architecture design and implementation. As the reader will easily find out, the subject of digital modem design and implementation is addressed in the book starting from a theoretical approach (supported by proper bibliographic references), and is followed by application issues, with reference to an ESA experiment assumed as a case study. A complete design flow, from specification to implementation, including testing and final verification is then presented. This leads the reader step-by-step to a thorough understanding of CDMA transmission and detection, and constitutes a practical guidance for the design of VLSI wireless mobile terminals.

[B3] F. Giannetti, M. Luise, "Spread-Spectrum Techniques for Mobile Communications", in M. Ibnkahla ed., "Signal Processing for Mobile Communications Handbook", CRC Press LLC, Boca Raton, FL, ISBN 0-8493-1657-X, 2004.

Wireless mobile communications has greatly benefited from the adoption of advanced signal processing techniques and components. In particular, the advent of low-cost very large scale integrated (VLSI) chips has allowed the design and implementation of efficient communications systems based on spread-spectrum signals, namely, the different code-division multiple-access (CDMA) radio networks currently in operation or being deployed. The aim of this chapter is to provide the reader with a basic understanding of the diverse digital signal processing (DSP) algorithms that lie at the foundation of such systems. After a short introduction to wireless communications (Section 10.1), the chapter develops into a description of the basic characteristics of digital spread-spectrum signals (Section 10.2). This sets the framework for the subsequent general study of CDMA techniques (Section 10.3) and description of current standards (Section 10.4). Next, the focus is shifted to the functions of signal synchronization for optimum data detection (Section 10.5) and to the design of a digital CDMA receiver (Section 10.6), highlighting the main relevant DPS-intensive tasks. The final part of the chapter is devoted to the introduction of an advanced topic related to the detection of digital information in a CDMA signal, namely, multiuser detection (Section 10.7).

[B4] F. Giannetti, M. Luise, "Spread-Spectrum Signals for Digital Communications", in H. Bidgoli ed., "The Handbook of Computer Networks", Wiley, Hoboken, NJ, ISBN 978-0471784616, 2007.

Wireless mobile communications took advantage of the adoption of Spread-Spectrum (SS) and Code Division Multiple Access (CDMA) technologies implemented through advanced Digital Signal Processing (DSP) techniques. In particular, the advent of low-cost Very Large Scale Integration (VLSI) chips has allowed the design and deployment of efficient commercial communication systems based on spread-spectrum signals, namely, the different CDMA cellular radio networks currently in operation or being deployed. The aim of this chapter is to provide the reader with a basic understanding of the spread-spectrum technologies that lie at the foundation of such systems. After a short introduction to wireless communications (Sect. 1), the chapter develops into a description of the basic characteristics of digital spread-spectrum signals (Sect. 2). This sets the framework for the subsequent study of CDMA communication systems (Sect. 3) including receiver architecture (Sect. 4). The final part of the chapter (Sect. 5) is devoted to the description of major second generation(2G), third generation (3G), and Beyond-3G CDMA techniques as implemented in different parts of the world.

[B5] F. Giannetti, L. Cobisi, P. Morandotti eds., "Da Marconi al 5G. Prospettive per le Comunicazioni Globali – Atti del XV Forum Italradio," printed by Nardini Editore, Florence, Italy, November 2019, ISBN-10: 8840473769, ISBN-13: 9788840473765.

JOURNALS

[J1] F. Giannetti, A. Lometti, "A Comprehensive Definition of Fire Codes", Journal of Information and Optimization Sciences, Vol. 13, No. 3, 1992, pp. 391-398.

We give a new definition of Fire codes and we discuss conditions for their existence. As a by-product, we find a new subclass of Fire codes. Finally, we overview some previous definitions of Fire codes and we point out some shortcomings which led to erroneous results.

[J2] R. De Gaudenzi, F. Giannetti, "Software Simulation Using TOPSIM-IV of a Satellite Mobile CDMA System for Digital Audio Broadcasting", TOPSIM-IV Users Group Bulletin, No. 2, July 1993, pp. 9-51.

Digital Audio Broadcasting (DAB) to mobile and fixed users exploiting the latest advances in compression, coding and transmission techniques represents an appealing application for future satellite systems. Due to the system complexity, a fully analytical approach to analyze the performance and optimize the transmission parameters is practically not feasible. In this case, a powerful and flexible simulation package is an essential tool to overcome the analytical difficulties. This paper introduces Coded Quasi-Orthogonal Code Division Multiplexing (CQO-CDM) as a transmission technique for Digital Audio Broadcasting and reports the results of the system analysis performed by using the TOPSIM-IV package. Preliminary satellite link budgets are provided by extensive computer simulations. Numerical results show that, by using a constellation of satellites in Highly Elliptical Orbit (HEO) complemented by terrestrial gap-filler network, it is possible to achieve a remarkable overall capacity. It has been also found that the proposed communication technique performs well over both the L-band satellite fading channel and the terrestrial gap-filler type of transmission and a variety of broadcasting services can be supplied with different data rates.

[J3] R. De Gaudenzi, F. Giannetti, "Analysis of an Advanced Satellite Digital Audio Broadcasting System and Complementary Terrestrial Gap-Filler Single Frequency Network", IEEE Transactions on Vehicular Technology, Vol. 43, No. 2, May 1994, pp. 194-210.

Digital Audio Broadcasting (DAB) to mobile and fixed users exploiting the latest advances in compression, coding and transmission techniques represents an appealing application for future satellite systems. This paper introduces Coded Quasi-Orthogonal Code Division Multiplexing (CQO-CDM) as transmission technique for digital audio broadcasting. The proposed technique performs well over both the L-band satellite fading channel and the terrestrial gap-filler type of transmission. Preliminary link budgets based on extensive computer simulation results are also provided. Numerical results show that a remarkable overall capacity can be achieved by using a constellation of satellites in Highly Elliptical Orbit (HEO) complemented by terrestrial gap-filler network. A variety of transmission rates, and hence broadcasting services, can be realized with the proposed transmission technique. It is shown that a Geostationary Orbit (GEO) satellite can provide limited service availability to mobile user, but it can also be used for experimental purposes.

[J4] R. De Gaudenzi, T. Garde, F. Giannetti, M. Luise, "A Performance Comparison of Orthogonal Code Division Multiple Access Techniques for Mobile Satellite Communications", IEEE Journal on Selected Areas in Communications, Vol. 13, No. 2, February 1995, pp. 325-332.

In recent years, Code Division Multiple Access (CDMA) techniques have received a great deal of attention for mobile terrestrial/satellite communication systems. Primarily considered for the noteworthy features of low power flux density emission and robustness to interference and multipath, CDMA is known to bear reduced bandwidth and power efficiency when compared to traditional TDMA and FDMA due to the intrinsic co-channel self-noise. Early attempts to increase the capacity of CDMA-based systems for commercial applications relied on voice activation and frequency reuse. More recently, practical solutions to implement (synchronous) orthogonal CDMA signalling are being developed independently in Europe and in the USA. This paper is focused on the comparative performance analysis of those two orthogonal CDMA schemes in the operating conditions of a mobile satellite communications system. In particular, the two CDMA systems are compared in the presence of frequency-selective multipath fading and a typical satellite transponder nonlinearity. Most numerical results are derived through a time-domain system simulation that confirms and integrates the theoretical findings.

[J5] F. Giannetti, M. Luise, R. Reggiannini, "Chip Timing Recovery in Digital Modems for Continuous-Phase CDMA Radio Communications", IEEE Transactions on Communications, Vol. 43, No. 2/3/4, February/March/April 1995, pp. 762-766.

In this correspondence, we consider the architecture of an all-digital modem for band-limited spread-spectrum radio communication networks employing code-division multiple access with Generalized MSK modulated signals. After a general description of the modem scheme, we specifically focus on the problem of spreading code synchronization, presenting three different chip timing recovery loops and analyzing their relative performance in terms of RMS tracking error.

[J6] R. De Gaudenzi, F. Giannetti, "Analysis and Performance Evaluation of Synchronous Trellis-Coded CDMA for Satellite Applications", IEEE Transactions on Communications, Vol. 43, No. 2/3/4, February/March/April 1995, pp. 1400-1408.

In this paper synchronous trellis-coded code division multiple access (S-TC-CDMA) for satellite communications is introduced and analyzed. Compared with asynchronous CDMA (A-CDMA) and uncoded synchronous CDMA (S-CDMA) systems, S-TC-CDMA improves the power and/or bandwidth efficiency by using trellis-coded PSK or QAM modulation in conjunction with independent orthogonal I-Q direct sequence spectrum spreading (DS/SS). An approximate formula for the bit error rate performance in the AWGN channel with co-channel interference has been derived and favorably compared to computer simulation results. Finally, we investigate the impairments due to the satellite nonlinearities and to the multipath fading and the system performace is reported.

[J7] R. De Gaudenzi, F. Giannetti, M. Luise, "Advances in Satellite CDMA Transmission for Mobile and Personal Communications", Proceedings of the IEEE, Vol. 84, No. 1, January 1996, pp. 18-39.

An ubiquitous network for multimedia personal communications (PCN, Personal Communications Network) with small, individual low-cost terminals is one of the most ambitious world-wide projects for the 21st century that are being pursued nowadays. In the development of such PCN, Geostationary, Medium and Low Earth Orbiting (GEO, MEO, LEO) satellite constellations will play a fundamental role to provide world-wide coverage for most services required by the end-user. The characteristics of efficiency and flexibility inherently required by that scenario suggest, amidst other possibilities, to take into special consideration a radio interface based on Code Division Multiple Access (CDMA) to ensure, in addition to the features mentioned above, a sufficient grade of power and spectral efficiency of the relevant satellite radio link. The aim of this paper is a review of the current status of those issues in the field of satellite CDMA transmission systems design that, in our opinion, appear fundamental to the successful operation of an efficient PCN. In particular, we survey the techniques for multiplexing, coding and transmission of Direct-Sequence Spread Spectrum (DS/SS) signals, and we touch upon the techniques for the minimization of the self-noise effect, and the related topics of power-control and multi-user detection. We also shortly address in this respect some technological aspects related to an efficient modem design via digital signal processing techniques. The final part of the paper deals more specifically with some typical issues of satellite transmission, namely the minimization of the detrimental effects of the nonlinear satellite transponder and of multipath propagation; the applicability of diversity reception to a multi-satellite network is also addressed as possible means of performance boost.

[J8] F. Giannetti, M. Luise, R. Reggiannini, "Continuous-Phase Modulations for CDMA Radio Communications: Modem Architecture and Performance", European Transactions on Telecommunications, Vol. 7, No. 3, May-June 1996, pp. 225-233.

In this paper we analyze the structure and the performance of a digital modem for band-limited spread-spectrum signals to be employed in a radio communication network with asynchronous code-division multiple access and constant-envelope continuous-phase modulation. After a description of the modem structure and the evaluation of its bit error rate in the presence of co-channel interference, we tackle the key point of code synchronization. In particular, we present a detailed analysis of the code acquisition strategy, assessing its performance in terms of false alarm probability, missed detection probability and mean acquisition time. Furthermore, we address the problem of code chip timing recovery, describing the performance of three different code tracking loops in terms of the steady-state RMS chip timing error jitter. The analytical approach we present can be applied to any Continuous Phase Modulation (CPM) format that can be approximated by an Offset-QAM signal, such as Gaussian-filtered Minimum-shift Keying (GMSK).

[J9] F. Giannetti, M. Luise, R. Reggiannini, "Performance Evaluation of a Continuous-Phase CDMA Modem Operating over the 60 GHz Mobile Radio Channel", European Transactions on Telecommunications, Vol. 7, No. 3, May-June 1996, pp. 255-265.

This paper describes the structure and the performance of a band-limited spread-spectrum transmission system suited for short-range terrestrial inter-vehicle or vehicle-to-beacon radio links that features Generalized MSK as modulation format and asynchronous direct-sequence code-division multiple access. The Bit Error Rate (BER) performance of such a system is evaluated over a recently proposed 60 GHz short-range mobile radio channel model. In particular, the sensitivity to a number of relevant link parameters (such as the distance between transmit and receive antennas and the receiver speed) is investigated, and the impact of code tracking errors and of differential encoding/detection of the spreading code chips on system performance is also discussed.

[J10] R. De Gaudenzi, F. Giannetti, M. Luise,"The Influence of Signal Quantization on the Performance of Digital Receivers for CDMA Radio Networks", European Transactions on Telecommunications, Vol. 8, No. 1, January-February 1997, pp. 89-97.

In an all-digital implementation of a data modem for Direct-Sequence Spread Spectrum (DS/SS) Code-Division Multiple Access (CDMA) systems, the in-phase and quadrature components of the received signal are customarily digitized just after IF matched filtering and baseband conversion. To reduce the processing effort in the data demodulator, it is of interest to represent the signals in the digital domain with as little a number of bits as possible. On the other hand, coarse signal quantization (down to 2-3 bits/sample) causes a non-negligible performance degradation as far as the receiver BER is concerned. The aim of this paper is thus the investigation of the impact of signal quantization on the BER performance of a DS/SS CDMA receiver in the presence of Gaussian noise and co-channel interference. Based on a general theoretical analysis, a few multiple access strategies are taken into consideration, and the theoretical findings are also checked by computer simulation. For all those systems, a four-bit ADC, yielding less than 0.5 dB signal-to-noise ratio degradation at a BER=10E-3 appears to provide a good trade-off between performance loss and demodulator complexity.

[J11] F. Giannetti, "Capacity Evaluation of a Cellular CDMA System Operating in the 63-64 GHz Band", IEEE Transactions on Vehicular Technology, Vol. 46, No. 1, February 1997, pp. 55-64.

In this paper a cellular asynchronous code-division multiple access (A-CDMA) system operating in the 63-64 GHz band for short-range communications is analyzed. A simple propagation model for the 63-64 GHz band is first introduced and discussed. The system capacity, expressed as the maximum number of users per cell, is then analytically derived and favorably compared with other CDMA schemes operating in conventional frequency bands (i.e. below 2 GHz). Also, simple expressions for the system bit error rate (BER) are analytically derived for different cases and validated through computer simulations. Finally, power requirements are derived and the impact of atmospheric conditions is evaluated. It turns out that the use of 63-64 GHz band significantly increases the capacity of A-CDMA, and proves to be suitable for cellular systems and personal communication networks (PCNs) provided that adequate power margins are taken into account in the design of the system.

[J12] A. Cavallini, F. Giannetti, M. Luise, R. Reggiannini, "Chip-Level Differential Encoding/Detection of Spread-Spectrum Signals for CDMA Radio Transmission over Fading Channels", IEEE Transactions on Communications, Vol. 45, No. 4, April 1997, pp. 456-463.

This paper is concerned with the design and performance evaluation of a direct-sequence, spread-spectrum transmission and signal detection technique for application to code division multiple access mobile radio networks. Unlike conventional differential encoding/detection of data symbols, such a technique envisages differential encoding/detection of the spreading code chips to counteract the fast time-selective fading encountered in mobile radio transmissions. Binary PSK modulation on a Ricean frequency-flat fading channel is assumed, with Gaussian and Rayleigh channels as particular cases. The bit error rate performance of the receiver is analytically evaluated as a function of the relevant system parameters and the impact on the receiver performance of a carrier frequency offset is also investigated.

[J13] R. De Gaudenzi, F. Giannetti, M. Luise, "Design of a Low-Complexity Adaptive Interference-Mitigating Detector for DS/SS Receivers in CDMA Radio Networks", IEEE Transactions on Communications, Vol. 46, No. 1, January 1998, pp. 125-134.

[J14] R. De Gaudenzi, F. Giannetti, M. Luise, "Signal Synchronization for Direct-Sequence Code-Division Multiple Access Radio Modems", European Transactions on Telecommunications, Vol. 9, No. 1, January/February 1998, pp. 73-89.

The design of low-complexity, -size, and -cost modems for Code-Division Multiple Access (CDMA) radio links like those envisaged in the 21st-century Personal Communications Network puts forth challenging issues as far as signal detection for best power efficiency is concerned. As is often the case in modem design, the ''ancillary'' functions of signal synchronization may reveal fundamental in such an optimum design problem. Spread-Spectrum CDMA signals reveal particularly demanding in this respect, so that the basic issues in carrier, code and chip/data timing should be carefully re-considered before tackling light-heartedly the design of a Digital Signal Processing (DSP)-based CDMA modem. It is the aim of this paper to present an overview of those code acquisition/tracking and carrier frequency/phase recovery techniques for a Direct-Sequence Spread-Spectrum signal, that appear particularly suited to an efficient VLSI implementation

[J15] R. De Gaudenzi, F. Giannetti, M. Luise, "Signal Recognition and Signature Code Acquisition in CDMA Mobile Packet Communications", IEEE Transactions on Vehicular Technology, Vol. 47, No. 1, February 1998, pp. 196-208.

Fast and reliable signal sense and signature code synchronization for Direct-Sequence Spread Spectrum (DS-SS) signals are key issues in the design of the receiver for modern packet Code-Division Multiple Access (CDMA) radio networks for mobile communications; this motivates the study of the signal recognition and code acquisition (SR/CA) scheme we describe in this paper. Specifically, starting form elementary estimation and detection theory criteria, we work out a non-coherent parallel SR/CA algorithm that is suited to a full-digital implementation in a single Application-Specific Integrated Circuit (ASIC). The results of a theoretical analysis of such a scheme, encompassing Additive White Gaussian Noise (AWGN) and Multiple Access Interference (MAI), are integrated and validated by an overall time-domain system simulation. We also evaluate through a simplified approach the impact of some degradation factors on the overall circuit performance, namely sampling epoch and carrier frequency offset, and one-bit signal quantization, to allow optimization of the design parameters as a function of the characteristics of the received signal.

[J16] R. De Gaudenzi, F. Giannetti, "DS-CDMA Satellite Diversity Reception for Personal Satellite Communication: Satellite-to-Mobile Link Performance Analysis", IEEE Transactions on Vehicular Technology, Vol. 47, No. 2, May 1998, pp. 658-672.

The satellite-to-mobile link of a mobile personal satellite communication system employing power-controlled Direct-Sequence Code Division Multiple Access (DS-CDMA) and exploiting satellite-diversity is analyzed and its performance compared with a more traditional communication system utilizing single satellite reception. The semi-analytical model developed has been thoroughly validated by means of extensive Monte Carlo computer simulations. System capacity and performance have been numerically evaluated in the presence of a realistic operating scenario, including antenna radiation pattern, imperfect power-control, shadowing and cross-polarization effects. It is shown how the capacity gain provided by diversity reception considerably shrinks in the presence of increasing traffic or in the case of mild shadowing conditions. Moreover, the quantitative results tend to indicate that to combat system capacity reduction due to the intra-system interference, no more than two satellites sharing the same frequency slot must be active over the same region.

[J17] R. De Gaudenzi, L. Fanucci, F. Giannetti M. Luise, "VLSI Implementation of a Signal Recognition and Code Acquisition Algorithm for CDMA Packet Receivers", IEEE Journal on Selected Areas in Communications, Vol. 16, No. 9, December 1998, pp. 1796-1808.

The widespread application of Direct-Sequence Spread-Spectrum Code Division Multiple Access (DS/SS-CDMA) to wireless communication systems asks for ever faster and more reliable real-time signal processing operations to be performed by highly-integrated and low-power consumption digital receivers. One of the most critical signal processing tasks to be performed by the DS/SS-CDMA receiver is signal presence detection and code epoch estimation. This paper deals with the design and realization of an Application Specific Integrated Circuit (ASIC) for fast Signal Recognition and Code Acquisition (SR/CA) in Packet DS/SS-CDMA receivers operating in a satellite or terrestrial radio network. In particular, we show how a parallel acquisition circuit can be effectively implemented on a single-chip with a 1.0 um CMOS (Complementary Metal Oxide Silicon) technology according to the specification ARCANET Ku-band CDMA VSAT satellite network sponsored by of the European Space Agency (ESA). It is shown that the ASIC performance closely follows analytical predictions.

[J18] R. De Gaudenzi, F. Giannetti, M. Luise, "Capacity of a Multi-Beam, Multi-Satellite CDMA Mobile Radio Network with Interference-Mitigating Receivers", IEEE Journal on Selected Areas in Communications, Vol. 17, No. 2, February 1999, pp. 204-213.

More and more interference-mitigating algorithms arebeing investigated in an attempt to increase the capacity of code-division multiple access radio networks. At the moment, the main question about interference-resilient receivers is: do they really bring forth the capacity increase they promise on theoretical grounds? The aim of this study is to give a preliminary answer to such a question, through the capacity analysis of the forward link of a multi-satellite, multi-beam, radio communication network at S-band. Specifically, starting from simplified yet realistic assumptions on the beam layout, the antenna footprint shape, and the coding/multiplexing /modulation and power control strategies, it is shown that the blind, adaptive, interference-mitigation receiver, selected as an appealing representative of the lot, can indeed boost the system quality of service in terms of outage probability. The results are derived after a mix of theoretical analysis (as far as the detector performance evaluation is concerned) and simulation (to examine a number of different random system configurations) to circumvent the inherent complexity of the issue.

[J19] F. Giannetti, M. Luise, R. Reggiannini, "Mobile and Personal Communications in the 60 GHz Band: a Survey", Wireless Personal Communications, Vol. 10, Issue 2, July 1999, pp. 207-243, published by Kluwer Academic Publishers, Dordrecht, The Netherlands.

This paper intends to present a summary of the technical issues arising in the exploitation of the 60 GHz mm-wave band for mobile and personal communications. The most significant applications proposed so far are surveyed, with particular emphasis placed on recent experimentation about millimeter-wave propagation for road/railway transportation as well as indoor scenarios. As a case study, the capacity of a (micro-)cellular Code Division Multiple Access (CDMA) network in the 60-GHz band is also evaluated in detail.

[J20] F. Giannetti, M. Luise, R. Reggiannini, "Simple Carrier Frequency Rate-of-Change Estimators", IEEE Transactions on Communications, Vol. 47, No. 9, September 1999, pp. 1310-1314.

This paper is concerned with the estimation of the rate-of-change of the instantaneous frequency of an unmodulated carrier. Such an issue arises for instance in satellite communication systems based on a Low-Earth-Orbit (LEO) constellation, wherein the velocity of each satellite relative to Earth is rapidly time-varying and, consequently, the received carrier is affected by non-negligible Doppler shift and Doppler rate. First, we present simple, yet efficient estimators of the Doppler rate derived from maximum likelihood estimation theory. Next, we investigate their performance in terms of bias and estimation error variance and finally, we compare our variance results with the relevant Modified Cramer-Rao Bound.

[J21] J. Romero-Garcia, R. De Gaudenzi, F. Giannetti, M. Luise, "A Frequency Error Resistant Blind CDMA Detector", IEEE Transactions on Communications, Vol. 48, No. 7, July 2000, pp. 1070-1076.

This paper presents an enhanced version of the recently-proposed Blind Anchored Interference-Mitigating Detector (BAID) for Code Division Multiple Access (CDMA) transmission. Such a detector, named Extended Complex BAID (EC-BAID), features invariance to a phase error on the useful channel's carrier and reveals resistant to a large frequency shift (e.g. Doppler shift) on interfering carriers. The EC-BAID is also shown to bear a sensitivity to residual carrier frequency errors on the desired channel which is lower by three orders of magnitude with respect to the case of a Data-Aided Minimum Mean Square Error (DA-MMSE) receiver. The performance of the EC-BAID is computed theoretically, and is validated by computer simulations under a variety of system configurations.

[J22] L. Fanucci, E. Letta, R. De Gaudenzi, F. Giannetti, M. Luise, "VLSI Implementation of a CDMA Blind Adaptive Interference-Mitigating Detector", IEEE Journal on Selected Areas in Communications, Vol. 19, No. 2, February 2001, pp. 179-190.

This paper presents the design and the main performance results of a single ASIC implementation of the recently-proposed extended complex-valued blind anchored interference-mitigating detector (EC-BAID) for code division multiple access (CDMA) transmission. Such a detector, which exhibits a remarkable robustness to multiple access interference, operates in blind mode, i.e., it requires only the knowledge of the timing of the wanted user's signature code, and it is therefore very well suited for integration into handheld single-user terminal demodulators. The implementation of the interference-mitigating detector is based on a patented optimized architecture which leads, in 0.25-um CMOS technology, to a roughly 25 Kgate plus 23-Kbit RAM single-chip ASIC supporting chip rates up to 4 Mchip/s with a maximum internal clock frequency of 32.768 MHz. The main design drivers are thoroughly discussed and the relevant performance results are compared to the theoretical behavior. A possible extension to multi-rate CDMA systems adopting orthogonal variable spreading factor (OVSF) sequences is also briefly addressed.

[J23] L. Fanucci, R. De Gaudenzi, F. Giannetti, M. Luise, M. Rovini, "Design, Implementation and Verification through a Real-Time Test-Bed of a Multi-Rate CDMA Adaptive Interference Mitigation Receiver for Satellite Communication", International Journal of Satellite Communications and Networking, Vol. 21, Issue 1 (January/February), 2003, pp. 39-64, published by John Wiley & Sons Ltd.

This paper presents the design, the implementation, and the main performance results of a multi-rate code division multiple access (CDMA) interference mitigation receiver for satellite communication. Such activity was performed within a research project supported by the European Space Agency (ESA), whose aim was to demonstrate the suitability of the linear adaptive interference mitigation detector (IMD) named extended complex-valued blind anchored interference-mitigating detector (EC-BAID) for single-user detection of a CDMA signal in third-generation (3G) satellite networks. Such a detector, which exhibits a remarkable robustness to multiple access interference, operates in a blind mode, i.e. it only requires knowledge of the timing of the wanted user's signature code, and is therefore very well suited for integration into handheld user terminals. Experimental results in terms of bit error rate with respect to the theoretical behaviour were derived through a specifically developed test bed. Signal plus multiple access interference generation is performed via a computer-controlled arbitrary waveform generator, followed by frequency up-conversion to the standard intermediate frequency of 70 MHz. Additive white Gaussian noise is then injected with the aid of a precision noise generator. The core of the test bed is a flexible digital receiver prototype featuring the EC-BAID detector plus all functions ancillary to IMD (multi-rate front-end, automatic gain control, code acquisition and tracking, carrier synchronization, etc.). Those functions were implemented through careful mixing of different technologies: field programmable gate arrays (FPGAs) for computing-intensive signal processing functions, digital signal processor (DSP) for housekeeping and monitoring, and application specific integrated circuit (ASIC) for adaptive IMD. The adopted design flow also allows an easy re-use of the prototype architecture to come to an overall integration of the receiver into a single ASIC with modest complexity and power consumption increase with respect to a conventional detector.

[J24] M. Porretta, P. Nepa, G. Manara, F. Giannetti, M. Dohler, B. Allen, A.H. Aghvami, "A Novel User Positioning Technique for Microcellular Wireless Networks", IEE Electronics Letters, Vol. 39, No. 3, 1st May 2003, pp. 745-747.

This letter presents a novel algorithm that makes use of a single base station to locate mobile terminals in cellular networks, by resorting to a triangulation technique supported by minimal information about the environment in the base station neighbourhood. The algorithm is shown to perform well when operating in a microcellular environment and perfect channel estimation is assumed.

[J25] R. De Gaudenzi, L. Fanucci, F. Giannetti, M. Luise, M. Rovini, "Satellite mobile communications spread-spectrum receiver", IEEE Aerospace and Electronic Systems Magazine, Vol. 18, Issue 8, August 2003, pp. 23-30.

Universal Mobile Telecommunication System (UMTS) has reached the headlines of worldwide newspapers around 2000 in coincidence with the auctions for the frequency licenses, which took place in several European countries. During such auctions the cost of spectrum licenses in countries like United Kingdom and Germany reached unprecedented levels for mobile operators. The large expectation around Third-Generation (3G) mobile wireless systems, of which UMTS represents the European interpretation, unfortunately did not materialize yet. However, despite the delays in the commercial roll-out and the skepticism affecting the telecommunication world at whole, UMTS will certainly play a key role in the development of multimedia wireless services. Although it is difficult to predict which kind of avenues 3G services will take, it is clear that the availability on the same device (user terminal) of multimedia interactive services combined with accurate localization will open-up astonishing possibilities to service providers. In addition to the current voice and short-message services, mobile users will be able to access the Internet at considerable peak speeds, download and upload documents, images, MP3 files, receive location dependent information and so on. The mobile terminal functionalities will be greatly extended to make it a truly interactive Personal Digital Assistant always connected to the Internet world and voice will just become one of the many multimedia services available at the user’s fingertips. UMTS was originally intended to be made of a terrestrial (T-UMTS) and a satellite component (S-UMTS) integrated in a seamless way. The economical troubles experienced by second generation satellite global mobile personal communication systems (GMPCS) such as Iridium and Globalstar have largely mitigated the investor enthusiasm for satellite-based ventures. Those GMPCS systems are based on large Low Earth Orbiting (LEO) 48-64 satellite constellations aimed to provide GSM-like services from hand-held terminals with worldwide coverage. However, despite the severe financial difficulties encountered by LEO GMPCS, new regional systems based on geostationary (GEO) satellites, such as Thuraya and AceS, have been put in operation recently. Furthermore, Inmarsat, the first and most successful satellite mobile operator, is planning to put into orbit new powerful GEO satellites providing UMTS-like services in the near future. Since 1999, ESA has conducted a number of system studies and technological developments to support the European and Canadian industry in the definition of a Satellite UMTS (S-UMTS) component development strategy, identifying critical technological areas and promoting S-UMTS demonstrations. Particular effort has been devoted to the following key aspects: a) study and optimization of system architectures providing appealing features to possible operators; b) design, testing and standardization within international bodies of an air interface with maximum commonality with terrestrial UMTS; c) development and validation of real-time demonstrators for laboratory and over the-air S-UMTS experiments; d) design and development of large reflector antennas; e) design and prototyping of an advanced high-throughput On-Board Processor for future mobile missions; f) networking studies and simulations. Furthermore, ESA, in strict cooperation with the European Commission, has promoted the creation of the Advanced Mobile Satellite Task Force (ASMS-TF) which has now attracted more than 45 world-wide key players working together to define and defend the role of satellite in 3G mobile and beyond.

[J26] M. Porretta, P. Nepa, G. Manara, F. Giannetti, M. Dohler, B. Allen, A.H. Aghvami, "A Novel Single Base Station Location Technique for Microcellular Wireless Networks: Description and Validation by a Deterministic Propagation Model", IEEE Transactions on Vehicular Technology, Vol. 53, No. 5, September 2004, pp. 1502-1514.

Positioning algorithms in cellular networks have become increasingly important as a means of supporting emerging services that require a sufficiently precise estimation of the position of the mobile terminal (MT) associated to a given base station (BS). Currently, even the most sophisticated positioning algorithms require at least three BSs to achieve satisfactory precision. This paper presents a novel algorithm that makes use of a single BS antenna array to locate MTs in cellular networks. A triangulation technique is utilised and supported by some minimal information about the environment in the BS neighbourhood. The algorithm is shown to perform well when operating in a microcellular environment with perfect channel parameter estimation. The effect of finite resolution of the input parameters is also investigated. The performance is analysed for a Universal Mobile Telecommunications System (UMTS) microcellular scenario through a 3D deterministic channel model. Finally, the performance of the proposed positioning technique is compared to the well-known location method based on time of arrival measurements at three different BSs.

[J27] F. Giannetti, P. Nepa, M. Michelini, G. Manara, N.A. D’Andrea, "Interactive Laboratory Exercises for Telecommunication Engineering Learning", IADAT Journal of Advanced Technology on Education, ISSN 1698-1073, Vol. 2, No. 1, September 2005, pp. 215-217.

This contribution presents the use of an educational system for interactive laboratory exercises devoted to undergraduate students attending telecommunication engineering courses. The system supports remote control of the instruments via TCP/IP and allows laboratory exercises with real instruments to be remotely performed also by students which can not attend classroom lessons. Furthermore, expensive single-copy equipments can be effectively shared among several students that work with real data, acquired by actual instruments. The system supports a broad set of instruments for measurements on communication equipments and microwave devices.

[J28] N.A. D’Andrea, F. Giannetti, M. Michelini, "Software Didattico per l'Emulazione di Sistemi di Comunicazione", (in Italian) LabVIEW World, ISSN 1972-3008, September 2006, pp. 27-28.

Con LabVIEW 7.1, LabVIEW Application Builder 7.1 e LabVIEW Run-Time Engine 7.1 sono stati realizzati applicativi didattici interattivi che emulano il funzionamento di strumentazione per misure su sistemi di telecomunicazioni, in modo da consentire agli studenti di operare come se stessero utilizzando gli apparati reali.

[J29] N.A. D’Andrea, F. Giannetti, M. Michelini, G. Manara, P. Nepa, "A Library of Virtual Instruments Applications for Education in Telecommunications Engineering", IADAT Journal of Advanced Technology on Education, ISSN 1698-1073, Vol. 2, No. 3, September 2006, pp. 288-290.

This paper describes an educational library of virtual instruments applications allowing the simulation of communication systems and measuring instruments. The software tools have been developed with National Instruments’ LabVIEW™ environment and are being used in the Laboratory of Telecommunications and Applied Electromagnetics, at the University of Pisa, Italy.

[J30] F. Giannetti, M. Luise, "Digital Satellite Receiver for Wideband Multi-Rate Ka-Band Communications", IEEE Transactions on Aerospace and Electronic Systems, Vol. 43, No. 2, April 2007, pp. 826-832.

This correspondence presents the architecture of a high-speed low-complexity digital receiver for wideband satellite communications supporting multiple baud rates, ranging from 10 to 200 MBaud. The design of the modem is based on the Cascaded Integrator-Comb (CIC) scheme which exploits a parallel processing so as to provide an outstanding decimation agility. Eventually, bit error rate (BER) performance of the multi-rate receiver are assessed by floating-point simulations.

[J31] N.A. D'Andrea, F. Giannetti, G. Manara, M. Michelini, P. Nepa, "Educational Set-Up for Microwave Laboratory Activities Using Virtual Instruments and Real Data", Microwave Review, ISSN 14505835, Vol. 13, No. 2, December 2007, pp. 12-17.

This paper describes a virtual educational laboratory to be used for experimental activities in the framework of Telecommunications Engineering courses. The proposed approach is based on a set of software interfaces, named virtual instruments (VIs) and developed with LabVIEW(TM) environment, which are able to emulate hardware instruments. The aim of the project is to allow the students to perform experimental activities, either in the college labs or at home, without the physical availability of measurement instruments by simply using software emulators of real instruments that process real data acquired from real world. The system is being used in the Laboratory of Telecommunications and Microwave of the Engineering college of the University of Pisa, Italy..

[J32] N.A. D'Andrea, F. Giannetti, G. Manara, M. Michelini, P. Nepa, "A Virtual Educational Laboratory for Telecommunications Engineering", The International Journal of Engineering Education, ISSN 0949-149X, Vol. 24, No. 1, 2008, pp. 144-152.

We present a virtual educational laboratory that allows the simulation of communication systems, equipment, devices, and measuring instruments, developed by using the software environment LabVIEW(TM) from National Instruments. The system, which fulfills the need for a flexible and low-cost educational tool for laboratory practice, is being used in the Laboratory of Telecommunications and Applied Electromagnetics of the Engineering College of the University of Pisa, Italy.

[J33] M. Porretta, P. Nepa, G. Manara, F. Giannetti, "Location, Location, Location", IEEE Vehicular Technology Magazine, Vol. 3, Issue 2, June 2008, pp. 20-29.

In the last decade, location and tracking of a mobile terminal (MT) in wireless communication networks has attracted a lot of attention. Historically, the need for pinpointing a mobile user arises as a matter of security, in order to track emergency calls made trough the US Enhanced 911 (E-911) service. Nevertheless, there are many other applications that make positioning techniques attractive for wireless service providers, such as mobile yellow pages, ''where I am'' applications, navigation services, location-sensitive billing, restaurant/hotel finders, mobile gaming, and so forth. Moreover, position location systems enhance public interest services, such as fleet management, roadside assistance, traffic routing and real-time vehicle scheduling. Real-time position location can also be used to track service personnel (e.g., police officers, rescue teams, fire brigades, etc.), lost children, suspected criminals and stolen vehicles. Finally, subscriber location positioning allows service providers to improve network design and yields resource optimization. For instance, spectral efficiency can be improved and a more effective radio resource management (RRM) can be obtained through channel allocation based on actual mobile user location. Among the many location systems proposed in the literature, the most effective are those based on radiolocation techniques that exploit measurements of physical quantities related to radio signals travelling between the MT and a given set of transceivers whose location is known, e.g. base stations (BSs) and/or navigation satellites. Radio signal measurements are typically the received signal strength (RSS), the angle of arrival (AOA), the time of arrival (TOA), and the time difference of arrival (TDOA). More recently, radio location algorithms based on a combination of the above location-related measurements have also been proposed. Such hybrid techniques guarantee a high-accuracy location, which is more and more required by value-added location-based services, as for example security applications and mobile gaming.

[J34] F. Giannetti, V. Lottici, I. Stupia, "Iterative Multi-User Data Predistortion for MC-CDMA Communications", IEEE Transactions on Wireless Communications, Vol. 7, Issue 10, October 2008, pp. 3823-3833.

An efficient and flexible air interface is the necessary condition to achieve the ambitious goals of next generation broadband wireless networks. Multicarrier code division multiple access (MC-CDMA) is a practical answer to this need, but the considerable vulnerability to nonlinear distortions induced by high power amplifiers at the transmitter side hinders its appealing features, thereby demanding for adequate countermeasures. The current paper contributes to this issue with a novel multiuser data predistortion (MUDP) procedure aimed at mitigating the performance degradation of a MC-CDMA forward-link in the presence of a nonlinear channel. The proposed MUDP resides entirely at the transmitter of the base station, and simply requires a set of modified constellations, which are jointly and iteratively optimized so that the distortions experienced by each active user are significantly reduced. The required computational complexity is then kept at affordable levels by resorting to a suboptimal yet effective scheme based on the identification of the strongest interfering users combined with the set-partitioning and the symmetry properties of their constellations. Numerical simulation results corroborate the effectiveness of the MUDP in improving the link performance under typical demanding multiple-access operating conditions.

[J35] G. Tiberi, S. Bertini, A. Monorchio, F. Giannetti, G. Manara, "Computationally Efficient Ray-Tracing Technique for Modelling Ultrawideband Indoor Propagation Channels", IET Microwaves, Antennas & Propagation, Vol. 3, Issue 3, April 2009, pp. 395–401.

The design and development of high-speed data wireless communication systems within buildings call for the investigation of the ultrawideband indoor propagation channel. To date, ray tracing (RT) based approaches have been widely used to characterise the channel; unfortunately, such techniques, although accurate, turn out computationally intensive. In this work, a parallel ray (PR) approximation is successfully used to significantly improve the computational efficiency of the RT method. The accuracy and the applicability of the proposed approximation are assessed through the analysis of the mean square error between the impulse responses obtained with the PR and the RT methods.

[J36] F. Giannetti, V. Lottici, I. Stupia, "Theoretical Performance of Bandlimited MC-CDMA Systems over Nonlinear Channels", IEEE Transactions on Communications, Vol. 57, No. 6, June 2009, pp. 1638-1642.

In multicarrier (MC) broadband wireless networks, nonlinear power amplification is one of the main performance limiting factor, and therefore its effects have to be properly quantified during the design phase of the radio links. This letter outlines an analytical framework for the forward-link of a bandlimited MC code division multiple access that intends to fulfill this need while improving the scarce efficiency of conventional simulation-based-only design procedures. Through the extended Bussgang theorem, the approach presented herein yields a theoretical description of several time- and frequency-domain system features, such as transmitted signal power spectrum, constellation warping, nonlinear distortion noise and BER metric. Extensive simulation results verify the accuracy of the proposed analysis under typical multiple-access operating conditions.

[J37] F. Giannetti, M. Michelini, N.A. D'Andrea, "Instruments Go Virtual: Experiences on Educational Activities in the Field of Telecommunications at the University of Pisa", Microwave Review, ISSN 14505835, Vol. 15, No. 1, June 2009, pp. 8-16.

This paper illustrates the experience gained on educational activities in the field of telecommunications at the University of Pisa, Italy. The aim that drove the efforts of a team of teachers of telecommunications at the Engineering college was to allow the students to perform experiments, either in their college labs or at home, with virtual or remotely-controlled instruments. Starting from early lab demonstrations based upon single-copy hardware instrumentation, it is shown how the introduction of software interfaces, named virtual instruments (VIs), especially developed with National Instrument’s LabVIEW(TM) environment, greatly improved the effectiveness of experimental activities in the framework of telecommunications engineering courses. The main features of the proposed educational system, the set of available VIs and the operational modes are presented and discussed, together with their utilization in education and the relevant pedagogical benefits. The system is being used in the Laboratory of Telecommunications of the Engineering college of the University of Pisa, Italy.

[J38] F. Giannetti, V. Lottici, I. Stupia, "PAPR Analytical Characterization and Reduced-PAPR Code Allocation Strategy for MC-CDMA Transmissions", IEEE Transactions on Wireless Communications, Vol. 10, Issue 1, January 2011, pp. 219-227.

In this paper, an approximate analytical expression for the peak-to-average power ratio (PAPR) of a Multi- Carrier Code Division Multiple Access (MC-CDMA) signal is derived. Then, it is demonstrated that the PAPR of a MCCDMA system employing Walsh-Hadamard (WH) codes can be suitably reduced by resorting to a judicious strategy for the allocation of the spreading signature codes. Eventually, a low complexity implementation of the proposed strategy is presented and the relevant benefits, in terms of peak signal occurrence and robustness against nonlinear distortions, is numerically assessed over conventional random allocation strategy.

[J39] F. Principe, G. Bacci, F. Giannetti, M. Luise, "Software-Defined Radio Technologies for GNSS Receivers: A Tutorial Approach to a Simple Design and Implementation", Hindawi Publishing Corporation, International Journal of Navigation and Observation (IJNO), Vol. 2011, Article ID 979815, 27 pages.

The field of Satellite Navigation has witnessed the advent of a number of new systems and technologies: after the landmark design and development of the Global Positioning System (GPS), a number of new independent Global Navigation Satellite Systems (GNSS) were designed and were or are being developed all over the world: Russia's GLONASS, Europe's GALILEO, China's BEIDOU-2. Not to mention the augmentation systems and technologies like WAAS in the USA, EGNOS in Europe, and MSAS in Japan, and the modernization efforts of GPS itself. In this ever-changing context, the availability of reliable and flexible receivers is becoming a priority for a host of applications, including research, commercial, civil, and military. Flexible means here both easily upgradeable for future needs and/or on-the-fly reprogrammable to adapt to different signal formats. An effective approach to meet these design goals is the software-defined radio (SDR) paradigm. In the last few years, the availability of new processors with high computational power enabled the development of (fully-)software receivers whose performance is comparable to or better than that of conventional hardware devices, while providing all the advantages of a flexible and fully-configurable architecture. The aim of this tutorial paper is thus surveying the issue of the general architecture and design rules of a GNSS software receiver, through a comprehensive discussion of some techniques and algorithms, typically applied in simple PC-based receiver implementations.

[J40] R. Andreotti, I. Stupia, F. Giannetti, V. Lottici, L. Vandendorpe, "Packet Transmissions in Cognitive Radio Networks: How to Cheaply Get Efficiency and Reliability", COST Action IC0902 Newsletter, Issue 6, May 2012, pp. 2-3.

The ever growing demand for wireless multimedia applications and services occurred in the last years has spurred the research community to tackle several demanding technical challenges. Advanced next-generation wireless systems solicit the designer to solve a hard multi-facet severely constrained problem, that is to say, providing very high data rates under strict quality of service (QoS) levels, while at the same time facing the lack of wide available segments in the overcrowded electromagnetic spectrum.

[J41] I. Stupia, V. Lottici, F. Giannetti, L. Vandendorpe, "Link Resource Adaptation for Multiantenna Bit-Interleaved Coded Multicarrier Systems", IEEE Transactions on Signal Processing, Vol. 60, No. 7, July 2012, pp. 3644-3656.

The availability of flexible radio interfaces capable of adapting their configuration to the time-varying operating environment is the key response to the demand encountered in modern wireless networks for high data rates under strict quality of service (QoS) constraints. To this end, this paper develops a novel link resource adaptation (LRA) scheme for soft-decoded multiantenna (MIMO) bit interleaved coded orthogonal frequency division multiplexing (BIC-OFDM) transmissions employing automatic repeat request (ARQ) mechanisms. As the first step, a simple link performance evaluation model based on the effective signal-to-noise ratio (SNR) mapping concept is derived in a closed-form expression that it is shown to yield better accuracy than previous techniques. Then, an effective LRA strategy is formulated taking advantage of that framework. The aim is maximizing the goodput (GP) metric, that is to say, the number of information bits delivered without error to the user by unit of time, over the available radio resources, such as the power distribution on the subchannels, coding rate,modulation order and the MIMO configuration. The numerical results demonstrate considerable performance gains comparedwith nonadaptive transmissions, while keeping the computational complexity at affordable levels in view of the specific structure of the GP objective function.

[J42] R. Andreotti, I. Stupia, V. Lottici, F. Giannetti, L. Vandendorpe, "Goodput-Based Link Resource Adaptation for Reliable Packet Transmissions in BIC-OFDM Cognitive Radio Networks", IEEE Transactions on Signal Processing, Vol. 61, No. 9, May 1, 2013, pp. 2267-2281.

Cognitive radio (CR) stands out as a potential cornerstone to break the spectrum gridlock through enabling the coexistence of licensed (primary) and unlicensed (secondary) users in the same bandwidth. This paper deals with a novel link resource adaptation (LRA) strategy to be applied in CR scenarios for reliable packet transmissions based on bit interleaved coded orthogonal frequency division multiplexing (BIC-OFDM). We first formulate the power allocation (PA) problem constrained by both the available power at the secondary transmitter (ST) and the interference tolerable at the primary receivers, aimed at maximizing the offered layer 3 data rate, i.e., the goodput (GP) metric. Then, we derive the optimal PA strategy resorting to the customary Lagrangian dual decomposition (LDD) technique, which, however, like many other conventional numerical methods, exhibits several drawbacks, such as slow convergence and need for parameter tuning. These restrictions are circumvented through the development of a novel iterative yet simple PA algorithm, referred to as successive set reduction (SSR) approach, whose optimality conditions are analytically demonstrated by resorting to the Quasi Variational Inequality (QVI) framework. Based on this PA algorithm, an adaptive modulation and coding (AMC) scheme at the ST is eventually derived. Simulation results over a realistic scenario corroborate the effectiveness of the proposed SSR-based AMC algorithm, highlighting the GP improvements over non-adaptive LRA techniques, besides a remarkable complexity reduction w.r.t. conventional numerical methods.

[J43] R. Andreotti, T. Wang, V. Lottici, F. Giannetti, L. Vandendorpe, “Resource Allocation via Max–Min Goodput Optimization for BIC-OFDMA Systems,” IEEE Transactions on Communications, Vol. 64, No. 6, June 2016, pp. 2412-2426.

In this paper, a novel resource allocation (RA) strategy is designed for the downlink of orthogonal frequency division multiple access (OFDMA) networks employing practical modulation and coding under quality of service constraints and retransmission techniques. Compared with previous works, two basic concepts are combined together, namely, i) taking the goodput (GP) as performance metric, and ii) ensuring maximum fairness among users. The resulting RA maximizes thus the GP of the worst user, optimizing subcarrier allocation (SA), per-subcarrier power allocation (PA), and adaptation of modulation and coding (AMC) of the active users, yielding a nonlinear nonconvex mixed optimization problem (OP). The intrinsic demanding difficulty of the OP is tackled by iteratively and optimally solving the AMC, PA and SA subproblems, devoting special care to the demanding nonlinear combinatorial SA-OP. First, the optimal (yet computationally complex) solution is found by applying the branch&bound method to the optimal SA solution found in the relaxed domain, and accordingly, it is taken as benchmark. Then, an innovative suboptimal yet efficient solution based on the metaheuristic ant colony optimization (ACO) framework is derived. The proposed RA strategy is corroborated by comprehensive simulations, showing improved performance even at the cost of affordable numerical complexity.

[J44] R. Andreotti, F. Giannetti, M. Luise, "Energy-efficient link resource allocation in the multibeam satellite downlink under QoS constraints", International Journal of Satellite Communications and Networking, Vol. 34, No. 5, September/October 2016, pp. 661–678.

This work deals with the issue of boosting the capacity of digital subscriber line networks in the presence of geographical gaps. To this aim, an effective approach consists in exploiting the downlink of multibeam satellites for the delivering of packed-based traffic, employing modulation and coding schemes denoted by very high spectral efficiency, such as in Digital Video Broadcasting-Satellite, version 2 and eXtension standard, although time-varying channel and interference may severely affect the quality of the communication. To cope with these issues, this paper proposes a novel link resource adaptation based on the following features. First, to efficiently manage packet-based transmissions, an adaptive coding and modulation scheme is derived aimed at maximizing the ‘goodput’, that is, the offered layer-3 data rate. Then, in order to mitigate the co-channel interference arising from beams exploiting the same band, an adaptive power control is also proposed. The goal of the latter is to maximize the energy efficiency of the satellite downlink guaranteeing a given quality-of-service, that is, a minimum-goodput, over each link. This problem is modeled as a non-cooperative game, and the conditions of feasibility, existence, and uniqueness of the solution are analytically derived. Finally, simulation results are provided comparing the proposed strategy with the conventional rate satisfaction power control approach.

[J45] R. Andreotti, P. Del Fiorentino, F. Giannetti, V. Lottici, “Power-Efficient Distributed Resource Allocation under Goodput QoS Constraints for Heterogeneous Networks,” EURASIP Journal on Advances in Signal Processing, December 2016, pp. 1-18.

This work proposes a distributed resource allocation (RA) algorithm for packet bit-interleaved-coded OFDM transmissions in the uplink of heterogeneous networks (HetNets), characterized by small cells deployed over a macro cell area and sharing the same band. Every user allocates its transmission resources, i.e., bits per active subcarrier, coding rate and power per subcarrier, to minimize the power consumption while both guaranteeing a target quality-of-service (QoS) and accounting for the interference inflicted by other users transmitting over the same band. The QoS consists of the number of information bits delivered in error free packets per unit of time, or goodput (GP), estimated at the transmitter by resorting to an efficient effective SNR mapping technique. First, the RA problem is solved in the point-to-point case, thus deriving an approximate yet accurate closed-form expression for the power allocation (PA). Then, the interference-limited HetNet case is examined, where the RA problem is described as a non-cooperative game, providing a solution in terms of generalized Nash equilibrium. Thanks to the closed-form of the PA, the solution analysis is based on the best response concept. Hence, sufficient conditions for existence and uniqueness of the solution are analytically derived, along with a distributed algorithm capable of reaching the game equilibrium.

[J46] J. Van Hecke, P. Del Fiorentino, R. Andreotti, V. Lottici, F. Giannetti, L. Vandendorpe, M. Moeneclaey, “Adaptive Coding and Modulation using imperfect CSI in cognitive BIC-OFDM systems,” EURASIP Journal on Wireless Communications and Networking, December 2016, pp. 1-14.

This work investigates adaptive coding and modulation (ACM) algorithms under the realistic assumption that the available channel state information (CSI) at the transmitter is imperfect due to estimation errors and/or feedback delays. First, we introduce an optimal performance metric for the secondary user (SU) bit-interleaved coded orthogonal frequency division multiplexing (BIC-OFDM) system, called the expected goodput (EGP). By using an accurate modeling approximation, we succeed in deriving a tractable and very accurate approximation for the EGP. This approximate EGP (AEGP) is then used for the derivation of several ACM algorithms which optimize the code rate, bit and energy allocation under a constraint on the interference caused to the PU network. In the numerical results, we show that the AEGP is far more accurate than previous attempts to model the GP with imperfect CSI. Further, we verify that, in spite of the imperfect nature of the available CSI, the derived ACM algorithms significantly increase the goodput of the SU network, compared to a non-adaptive selection of the transmission parameters.

[J47] J. Van Hecke, P. Del Fiorentino, V. Lottici, F. Giannetti, L. Vandendorpe, M. Moeneclaey, “Distributed Dynamic Resource Allocation for Cooperative Cognitive Radio Networks with Multi-Antenna Relay Selection,” IEEE Transactions on Wireless Communications, Vol. 16, No. 2, February 2017, pp. 1236-1249.

A cognitive radio scenario is considered where the signals transmitted by a secondary user (SU) are relayed by multi-antenna relays using an amplify-and-forward cooperation protocol. In this paper, the optimal power allocation and beamforming scheme is derived for the SU transmitters (SU-TXs) which minimizes the exact outage probability of the SU network with relay selection, under both a transmit power constraint and a constraint on the interference power generated at every primary user receiver. After deriving the optimal structure of the beamforming matrix, several distributed resource allocation algorithms are obtained for different levels of channel state information (CSI) at the SU-TXs: perfect CSI and imperfect CSI are considered, along with the case where only channel distribution information (CDI) is available. The numerical results show that the multi-antenna relays can significantly improve the performance of the SU network, which would otherwise be severely limited by the harsh interference constraints. Further, we also investigate how the number of relays, the number of antennas and the level of CSI impact the performance of the SU network.

[J48] F. Giannetti, “Coltano: the Forgotten Story of a Marconi's Early Powerful Station,” IEEE Aerospace and Electronic Systems Magazine, Vol. 32, No. 3, March 2017, pp. 16-29.

On September 8, 1902, at the dawn of wireless telegraphy age, Marconi was looking at the Tuscan coast from the cruiser "Carlo Alberto", back from a long trip where he successfully carried out many radio experiments in the northern seas. While passing in front of Leghorn Marconi expressed to the Admiral Mirabello his intention to build a powerful intercontinental station in the plain behind that city. The station, which would be the first in Marconi's home country (and one of the first in the world, too), was intended to provide radiotelegraphic connections with Africa and America in the very low-frequency (VLF) band, i.e., using carrier frequencies below 100 kHz, which, at the time, were believed to be the sole option for long-distance radio communications . The selected site for this purpose was Coltano, a marshy rural area between Pisa and Leghorn, near the Tyrrhenian. The station was inaugurated by Marconi itself in 1911 with transmissions to Clifden (Ireland) and Glace Bay (Canada), followed by a pioneeristic link reaching Massawa (Eritrea), across more than 2000 km of Sahara's dry soil, which, until then, was considered an unsurmountable obstacle for the propagation of low-frequency ground waves. This was just the first of a series of successes obtained by this once worldwide renowned, but now completely forgotten, radio station, born from Marconi's genius.

[J49] S. Saponara, F. Giannetti, B. Neri, “Design Exploration of mm-Wave Integrated Transceivers for Short-Range Mobile Communications Towards 5G”, Journal of Circuits, Systems, and Computers, Vol. 26, No. 4, April 2017, pp. 1-27.

This paper presents a design exploration, at both system and circuit levels, of integrated transceivers for the upcoming fifth generation (5G) of wireless communications. First, a system level model for 5G communications is carried out to derive transceiver design specifications. Being 5G still in pre-standardization phase, a few currently used standards (ECMA-387, IEEE 802.15.3c, and LTE-A) are taken into account as the reference for the signal format. Following a top-down flow, this work presents the design in 65 nm CMOS SOI and bulk technologies of the key blocks of a fully integrated transceiver: low noise amplifier (LNA), power amplifier (PA) and on-chip antenna. Different circuit topologies are presented and compared allowing for different trade-offs between gain, power consumption, noise figure, output power, linearity, integration cost and link performance. The best configuration of antenna and LNA co-design results in a peak gain higher than 27 dB, a noise figure below 5 dB and a power consumption of 35 mW. A linear PA design is presented to face the high Peak to Average Power Ratio (PAPR) of multi-carrier transmissions envisaged for 5G, featuring a 1 dB compression point output power (OP1dB) of 8.2 dBm. The delivered output power in the linear region can be increased up to 13.2 dBm by combining four basic PA blocks through a Wilkinson power combiner/divider circuit. The proposed circuits are shown to enable future 5G connections, operating in a mm-wave spectrum range (spanning 9 GHz, from 57 GHz to 66 GHz), with a data-rate of several Gb/s in a short-range scenario, spanning from few centimeters to tens of meters.

[J50] S. Saponara, F. Giannetti, G. Anastasi, B. Neri, "Exploiting mm-Wave Communications to Boost the Performance of Industrial Wireless Networks," IEEE Transactions on Industrial Informatics, Vol. 13, No. 3, June 2017, pp. 1460-1470.

This work explores the potentiality of millimeter waves (mmW) as physical layer in industrial wireless networks. Innovative models and a link design method are proposed to achieve reliable communication, at a distance of tens of meters for a single hop, even in harsh environments. By exploiting the worldwide-free band of several GHz, available around 60 GHz, mmW links allow to achieve a performance boosting of up to two orders of magnitude, w.r.t. conventional sub-6 GHz wireless links, in indoor industrial environments. Time slotted channel hopping and frequency-diversity can be implemented with a large number of channels, and with high bit rate (several Mb/s per channel). This allows for robust networking of high data-rate sensors, such as cameras, radars or laser scanners. Featuring a low bit error rate, mmW communication allows for low-latency link and large number of hops in networks with a large radius. Finally, it ensures interference separation from operating frequencies of electrical machines, switching converters, and other industrial wireless networks (e.g., 802.11 or 802.15). Implementation results for key HW blocks in low-cost technologies show the feasibility of mmW communication nodes with low-power and compact size.

[J51] F. Giannetti, R. Reggiannini, M. Moretti, E. Adirosi, L. Baldini, L. Facheris, A. Antonini, S. Melani, G. Bacci, A. Petrolino, A. Vaccaro, "Real-Time Rain Rate Evaluation via Satellite Downlink Signal Attenuation Measurement," Sensors (Special Issue Earth Observation and In-Situ Sensing for Risk Assessment from Natural Threats) 2017, 17(8), pp. 1-24.

We present the NEFOCAST project (named by the contraction of “Nefele”, which is the Italian spelling for the mythological cloud nymph Nephele, and “forecast”), funded by the Tuscany Region, about the feasibility of a system for the detection and monitoring of precipitation fields over the regional territory based on the use of a widespread network of new-generation Eutelsat “SmartLNB” (smart low-noise block converter) domestic terminals. Though primarily intended for interactive satellite services, these devices can also be used as weather sensors, as they have the capability of measuring the rain-induced attenuation incurred by the downlink signal and relaying it on an auxiliary return channel. We illustrate the NEFOCAST system architecture, consisting of the network of ground sensor terminals, the space segment, and the service center, which has the task of processing the information relayed by the terminals for generating rain field maps. We discuss a few methods that allow the conversion of a rain attenuation measurement into an instantaneous rainfall rate. Specifically, we discuss an exponential model relating the specific rain attenuation to the rainfall rate, whose coefficients were obtained from extensive experimental data. The above model permits the inferring of the rainfall rate from the total signal attenuation provided by the SmartLNB and from the link geometry knowledge. Some preliminary results obtained from a SmartLNB installed in Pisa are presented and compared with the output of a conventional tipping bucket rain gauge. It is shown that the NEFOCAST sensor is able to track the fast-varying rainfall rate accurately with no delay, as opposed to a conventional gauge.

[J52] R. Andreotti, V. Lottici, I. Stupia, F. Giannetti, “Cross-layer link adaptation for goodput optimization in MIMO BIC-OFDM systems,” EURASIP Journal on Wireless Communications and Networking, Springer, (2018) 2018:5, Published on: 4 January 2018, pp. 1-17.

This work proposes a novel cross-layer link performance prediction (LPP) model and link adaptation (LA) strategy for soft-decoded multiple-input multiple-output (MIMO) bit-interleaved coded orthogonal frequency division multiplexing (BIC-OFDM) systems employing hybrid automatic repeat request (HARQ) protocols. The derived LPP, exploiting the concept of effective signal-to-noise ratio mapping (ESM) to model system performance over frequency-selective channels, does not only account for the actual channel state information at the transmitter and the adoption of practical modulation and coding schemes (MCSs), but also for the effect of the HARQ mechanism with bit-level combining at the receiver. Such method, named aggregated ESM, or ?ESM for short, exhibits an accurate performance prediction combined with a closed-form solution, enabling a flexible LA strategy, that selects at every protocol round the MCS maximizing the expected goodput (EGP), i.e., the number of correctly received bits per unit of time. The analytical expression of the EGP is derived capitalizing on the ? ESM and resorting to the renewal theory. Simulation results carried out in realistic wireless scenarios corroborate our theoretical claims and show the performance gain obtained by the proposed ? ESM-based LA strategy when compared with the best LA algorithms proposed so far for the same kind of systems.

[J53] S. Melo, S. Maresca, S. Pinna, F. Scotti, M. Khosravanian, A. Cerqueira S. Jr., F. Giannetti, A. Das Barman, A. Bogoni, "Photonics-based Dual-band Radar for Landslides Monitoring in Presence of Multiple Scatterers," IEEE/OSA Journal of Lightwave Technology, Vol. 36, No. 12, June, 2018, pp. 2337-2343.

In this paper, a dual-band photonics-based radar system used for precise displacement measures in a multi-target scenario is described. The radar was designed for monitoring applications to prevent both structural failures of buildings and landslides. The radar system exploits the technique of Stepped Frequency Continuous Wave (SFCW) signal modulation and the displacement of the targets is evaluated through differential phase measurements. In this work, encouraged by the results already achieved in the single-target scenario, we present an investigation extended to the case of multiple targets. We aim to evaluate the accuracy of the displacement estimation both from a simulated and experimental point of view, and to understand how multiple targets impact on the final estimate of displacements. Simulation results demonstrate that it is possible to achieve a typical accuracy of less than 0:2 mm for distances up to 400 m. These results are confirmed by preliminary experimental outcomes, which take into account different operative conditions with multiple targets. Finally, concluding remarks and perspectives draw the agenda for our future investigations.

[J54] F. Giannetti, M. Moretti, R. Reggiannini, A. Vaccaro, "The NEFOCAST System for Detection and Estimation of Rainfall Fields by the Opportunistic Use of Broadcast Satellite Signals," IEEE Aerospace and Electronic Systems Magazine, Vol. 34, No. 6, June 2019, pp. 16-27.

In this paper we present results from the NEFOCAST project, funded by the Tuscany Region, aiming at detecting and estimating rainfall fields from the opportunistic use of the rain-induced excess attenuation incurred in the downlink channel by a commercial DVB satellite signal. The attenuation is estimated by reverse-engineering the effects of the various propagation phenomena affecting the received signal, among which, in first place, the perturbations factors affecting geostationary orbits, such as the gravitational attraction from the moon and the sun and the inhomogeneity in Earth mass distribution and, secondly, the small-scale irregularities in the atmospheric refractive index, causing rapid fluctuations in signal amplitude. The latter impairments, in particular, even if periodically counteracted by correction maneuvers, may give rise to significant departures of the actual satellite position from the nominal orbit. A further problem to deal with is the daily and seasonal random fluctuation of the rain height and altitude/size of the associated melting layer. All of the above issues lead to non-negligible random deviations from the dry nominal downlink attenuation, that can be misinterpreted as rain events. In this paper we show how to counteract these issues by employing two differentially-configured Kalman filters de-signed to track slow and fast changes of the received signal-to-noise ratio, so that the rain events can be reliably detected and the relevant rainfall rate estimated.

[J55] E. Adirosi, L. Facheris, F. Giannetti, S. Scarfone, G. Bacci, A. Mazza, A. Ortolani, L. Baldini, "Evaluation of Rainfall Estimation Derived From Commercial Interactive DVB Receivers Using Disdrometer, Rain Gauge, and Weather Radar," IEEE Transactions on Geoscience and Remote Sensing, Early Access, 14 December 2020, pp. 1-14.

Accurate measurement and monitoring of precipitation is crucial for many applications, such as flood and drought risk assessment and management. Conventional meteorological devices for estimating precipitation (i.e., rain gauges, disdrometers, active and passive remote sensors, be they ground-based, spaceborne, or airborne) have their own strengths and weaknesses. The latter are often related to time and space resolution, coverage, and cost. In the last two decades, several studies have been carried out to exploit opportunistic signals of terrestrial microwave communication links to improve precipitation estimation capability. This study describes and evaluates a method to retrieve rainfall rate from the signal-to-noise ratio obtained from commercial interactive digital video broadcasting (DVB) receivers [referred as to smart low-noise blocks (smartLNBs)]. During a 1-year measurement campaign carried out in Tuscany (Italy) with purposely deployed instruments, the precipitation values estimated from a set of SmartLNBs were compared with measurements from co-located rain gauges and disdrometer. The normalized mean absolute error (NMAE) and root-mean-square error (RMSE) obtained comparing the total cumulative precipitation from a SmartLNB and a disdrometer are 48.8% and 7.46 mm, respectively. Encouraging results also come from comparing the total precipitation amounts as measured by the SmartLNBs and by the rain gauges, with values of NMAE (respectively, RMSE) ranging between 44% and 82% (respectively, 5.2 and 11.5 mm).

CONFERENCES

[C1] F. Giannetti, A. Lometti, "An Efficient FEC Implementation in SDH Digital Radio Systems", IEEE GLOBECOM 1990, S. Diego, U.S.A., December 2-5, 1990, pp. 1209-1214.

The introduction of synchronous digital hierarchy (SDH) into transmission systems leads to serious compatibility problems in digital radio links. In view of an efficient employment of the existing channelling arrangements it seems necessary to make a suitable use of the redundancies already proviewed inside the frames of the new hierarchies. This paper proposes the insertion of an error correcting code for M-QAM modulations in the Section Overhead (SOH) bytes of the STM-1 frame. The relevant performances are analytically evaluated in presence of Additive White Gaussian Noise (AWGN) and by computer simulation.

[C2] R. De Gaudenzi, F. Giannetti, "Synchronous Trellis-Coded CDMA: Analysis and System Performance", IEEE ICC 1993, Geneva, Switzerland, May 23-26, 1993, pp. 1444-1448.

In this paper synchronous trellis-coded code-division multiple-access (S-TC-CDMA) is introduced and analyzed. Compared with uncoded synchronous CDMA and conventional code-division multiple-access systems, S-TC-CDMA greatly improves the power and/or the bandwidth efficiency using trellis-coded M-ary PSK or QAM modulation in conjunction with independent quasi-orthogonal I-Q direct-sequence spectrum spreading (DS/SS). Approximate system bit error rate performances derived for an AWGN channel with co-channel interference are favorably compared to computer simulation results. Fianlly, impairements due to satellite nonlinearities and multipath channel fading are discussed and system performance reported.

[C3] F. Giannetti, M. Luise, R. Reggiannini, "Design of an All-Digital Receiver for Narrowband Continuous-Phase Asynchronous CDMA Systems", IEEE ICC 1993, Geneva, Switzerland, May 23-26, 1993, pp. 468-472.

In this paper we analyze a full-digital receiver for band-limited spread-spectrum signals in a radio communication network employing asynchronous code-division multiplexing and constant-envelope continuous-phase modulations. After a description of the modem structure, we present a detailed analysis of the code synchronization strategy, both in the acquisition and in the tracking mode. Furthermore, we tackle the issue of the chip timing recovery, discussing first the impact of chip timing errors on code acquisition, and then evaluating the performance of thre different code tracking loops. In particular, the acquisition performance is assessed in terms of false alarm and miss probabilities as well as average lock-in time, while in the analysis of the tracking behaviour tha Root Mean Square (RMS) chip timing jitter is assumed as quality factor. these parameters are also derived by simulation with a good agreement with the theoretical results. The analytical approach presented in the paper has a rather general validity and may be applied to any Continuous Phase Modulation (CPM) format that can be approximated by an Offset-QAM signal, such as gaussian MSK.

[C4] E. Colzi, R. De Gaudenzi, C. Elia, F. Giannetti, R. Viola, "Diversity Reception for Advanced Multi-Satellite Networks: a CDMA Approach", International Mobile Satellite Conference 1993, JPL, Pasadena, California, U.S.A., June 16-18, 1993, JPL Publication 93-009, pp. 473-478.

Diversity reception for Synchronous CDMA (S-CDMA) is introduced and analyzed. A Gaussian co-channel synchronous and asynchronous interference approximation is derived to evaluate the effects of the system bit error rate. Numerical results are provided for a simple mobile communication system where the signal transmitted by two distinct satellites in visibility are coherently combined by a three fingers Rake receiver. A second example showing performance of an integrated ground/satellite single frequency network for digital audio broadcasting is presented. Results show the capacity advantage of utilizing Synchronous CDMA in combination with diversity reception.

[C5] A. Azzarelli, E. Colzi, R. De Gaudenzi, C. Elia, F. Giannetti, R. Viola, "Analysis of Transmission Schemes for Satellite Digital Audio Broadcasting", IEEE GLOBECOM 1993, Houston, Texas, U.S.A., November 29-December 2, 1993, pp. 1628-1633.

The European Space Agency (ESA) is presently studying different transmission techniques suited for satellite sound broadcasting services. In this paper we report preliminary results about the performance of two efficient trasmission techniques, namely Coded Orthogonal Frequency Division Multiplexing and Coded Quasi-Orthogonal Code Division Multiplexing. By means of a computer simulation approach, the performance of the two systems has been evaluated over the nonlinear satellite fading channel. Link budgets have been established for the case of Highly Elliptical Orbit (HEO) and Geostationary Orbit (GEO) satellites. Results show that both approaches are suited for satellite radio broadcasting presenting similar impairments over the nonlinear satellite fading channel.

[C6] R. De Gaudenzi, F. Giannetti, "Performance Analysis of a CDMA-Based Satellite-Mobile Audio Broadcasting System", IEEE International Zurich Seminar on Digital Communications 1994, Zurich, Switzerland, March 8-11, 1994, published by Springer-Verlag, Heidelberg, Germany, January 1994, pp. 400-416.

Digital Audio Broadcasting (DAB) to mobile and fixed users exploiting the latest advances in compression, coding and transmission techniques represents an appealing application for future satellite systems. This paper introduces Coded Quasi-Orthogonal Code Division Multiplexing (CQO-CDM) as transmission technique for Digital Audio Broadcasting. The proposed technique performs well over both the L-band satellite fading channel and the terrestrial gap-filler type of transmission. Preliminary link budgets based on extensive computer simulation results are reported. Numerical results show that a remarkable overall capacity can be achieved by using a constellation of satellites in Highly Elliptical Orbit (HEO) complemented by terrestrial gap-filler network. A variety of transmission rates, and hence broadcasting services, can be provided by the proposed transmission technique.

[C7] R. De Gaudenzi, F. Giannetti, M. Luise, "Evaluation of the Impact of Signal Quantization on the Performance of a Digital Data Demodulator for CDMA Satellite Receivers", 4th International Workshop on Digital Signal Processing Techniques Applied to Space Communications, King's College, London, England, September 26-28, 1994, ESA publication WPP-086, pp. 3.51-3.58.

In an all-digital implementation of a data modem for Direct-Sequence Spread Spectrum (DS/SS) CDMA systems, the in-phase and quadrature components of the received signal are usually digitized just after IF matched filtering and baseband conversion. To reduce the processing effort in the data demodulator, it is in general of interest to represent the signals in the digital domain with as little a number of bits as possible. On the other hand, coarse signal quantization (2-3 bits/sample) causes a non-negligible Bit Error Rate (BER) performance degradation. The aim of this paper is thus the investigation of the impact of signal quantization on the BER performance of a DS/SS CDMA digital receiver, in the presence of Gaussian noise and co-channel interference. Classical analysis techniques are, in this respect, suitably modified to get to simple approximate formulae to evaluate the overall system BER performance. The analytical results, validated by extensive computer simulations, show that a 4-bit quantizer, yielding less than 0.5 dB degradation, provides a good trade-off between performance loss and demodulator complexity.

[C8] R. De Gaudenzi, T. Garde, F. Giannetti, M. Luise, "An Overview of CDMA Techniques for Mobile and Personal Satellite Communications", (invited paper) 1st European Workshop on Mobile/Personal Satcoms, ESA/ESRIN, Frascati, Roma, Italy, October 13-14, 1994, published by Springer-Verlag, London, United Kingdom, 1995, pp. 78-104.

The recent application of Code Division Multiple Access (CDMA) to commercial terrestrial communication radio networks suggested the possibility of extending the same access technique to high-efficiency low-cost satellite systems. A great research and development effort has therefore started, and is still in progress, to match the requirements of modern commercial satellite networks, namely: low-cost user equipments on one side and power and spectral efficiency on the other. The aim of this contribution is to address the main topics in the development of such systems for satellite-based mobile and personal communications. More specifically, we investigate first the inherent trade-off between coding and spreading, then we touch upon the techniques for the minimization of the self-noise effect, and the related issues of power control, multi-user detection and satellite diversity. As a key factor in the successful deployment of CDMA networks, we shortly review some technological aspects related to an efficient modem design via digital signal processing techniques, and the possible consequent low-cost, small-size Application-Specific Integrated Circuit (ASIC) implementation. The final part of the paper deals with some system-related issues, like the effect of the nonlinear satellite transponder and the mobile multipath channel on the multiplexed user signal, and highlights the applicability of CDMA to the emerging new-generation services, such as Digital Audio Broadcasting (DAB), wideband mobile networks, and the like.

[C9] R. De Gaudenzi, T. Garde, F. Giannetti, M. Luise, "DS-CDMA Techniques for Mobile and Personal Satellite Communications: An Overview", (invited paper) IEEE 2nd Symposium on Communications and Vehicular Technology in the Benelux, Universite Catholique de Louvain, Louvain-la-Neuve, Belgium, November 2-3, 1994, pp. 113-127.

[C10] F. Giannetti, M. Luise, R. Reggiannini, "Analysis of a Digital Modem for Continuous-Phase CDMA Terrestrial Mobile Radio Communications over the 60 GHz Channel", IEEE GLOBECOM 1994, S. Francisco, California, U.S.A., November 27-December 1, 1994, pp. 999-1003.

This paper reports on the structure and the performance of a band-limited spread-spectrum transmission system employing Generalized MSK modulated signals together with asynchronous code-division multiple access. The system is intended for use in short-range terrestrial mobile radio links, particularly intervehicle or vehicle-to-infrastructure communications. The system performance over a recently proposed 60 GHz short-range mobile radio channel model is analyzed assuming the average bit error rate (BER) as a figure of merit. The BER sensitivity to a number of relevant link parameters, such as the distance between transmit and receive antennas and the receiver speed is investigated. Also, the impact of code tracking errors and of differential encoding/detection of the code chips on the overall performance is discussed.

[C11] R. De Gaudenzi, T. Garde, F. Giannetti, M. Luise, "Orthogonal CDMA Transmission for Satellite-Based Mobile Communications Radio Network", IEEE GLOBECOM 1994, S. Francisco, California, U.S.A., November 27-December 1, 1994, pp. 100-104.

Lately, Code Division Multiple Access (CDMA) techniques have received a great deal of attention for mobile terrestrial/satellite communication systems. Primarily considered for the noteworthy features of low power flux density emission and robustness to interference and multipath, CDMA is known to provide reduced bandwidth and power efficiency when compared to traditional TDMA and FDMA due to the intrinsic co-channel self-noise. Practical solutions currently under advanced deverlopment status in Europe and in the USA, respectively, propose to overcome such a shortcoming by implementing (synchronous) orthogonal CDMA signalling. This paper is focused on the comparative performance analysis of those two orthogonal CDMA schemes in the operating conditions of a mobile satellite communications system. In particular, starting from the analysis of the classical additive white Gaussian noise (AWGN) environment, the two CDMA systems are compared in the presence of carrier phase offset, frequency-selective multipath fading, and a typical satellite transponder nonlinearity.

[C12] R. De Gaudenzi, F. Giannetti, M. Luise, "The Effect of Signal Quantization on the Performance of DS/SS-CDMA Demodulators", IEEE GLOBECOM 1994, S. Francisco, California, U.S.A., November 27-December 1, 1994, pp. 994-998.

The dramatic performance improvements lately experienced by Application-Specific Integrated Circuits (ASICs) let us envisage a single-chip all-digital implementation of a data modem for Direct-Sequence Spread Spectrum (DS/SS) Code-Division Multiple Access (CDMA) systems. In this respect, it is of interest to represent the signals in the digital domain with a small number of bits. On the other hand, it is known that coarse signal quantization may cause a significant Bit-Error Rate (BER) performance degradation. This paper investigates on the impact of signal quantization on the BER performance of a DS/SS CDMA receiver in the presence of Gaussian noise and co-channel interference. Based on a general theoretical analysis, a few multiple access strategies are taken into consideration, and some simple design hints are derived and verified by computer simulation.

[C13] R. De Gaudenzi, F. Giannetti, "DS-CDMA Satellite Diversity Reception for Personal Satellite Communication: Downlink Performance Analysis", (invited paper) AIAA/ESA Workshop on International Cooperation in Satellite Communications, ESA/ESTEC, Noordwijk, The Netherlands, March 27-29, 1995, ESA publication SP-372, pp. 179-184.

The downlink of a satellite-mobile personal communication system employing power-controlled Direct-Sequence Code Division Multiple Access (DS-CDMA) and exploiting satellite-diversity is analyzed and its performance compared with a more traditional communication system utilizing single satellite reception. The analytical model developed has been thoroughly validated by means of extensive Monte Carlo computer simulations. It is shown how the capacity gain provided by diversity reception shrinks considerably in the presence of increasing traffic or in the case of light shadowing conditions. Moreover, the quantitative results tend to indicate that to combat system capacity reduction due to intra-system interference, no more than two satellites shall be active over the same region. To achieve higher system capacity, differently from terrestrial cellular systems, Multi-User Detection (MUD) techniques are likely to be required in the mobile user terminal, thus considerably increasing its complexity.

[C14] R. De Gaudenzi, F. Giannetti, M. Luise, "Synchronization for Code-Division Multiple Access Transmission: an Overview", (invited paper) IEEE Benelux Workshop on Synchronization and Equalization in Digital Communications, Universiteit Gent, Gent, Belgium, May 11, 1995, pp. 7-21.

Code-Division Multiple Access (CDMA) is being considered as one of the possible universal radio interface techniques for the next-generation Personal Communications Network (PCN). The development of the relevant power-efficient, small-size, and low-cost CDMA terminals calls for state-of-the-art signal synchronization and detection. In the framework of the design of such a power/bandwidth/cost-effective modem, we present in this paper a broad review of those code acquisition/tracking and carrier frequency/phase recovery techniques for a CDMA signal, that appear particularly suited to an efficient VLSI implementation.

[C15] R. De Gaudenzi, F. Giannetti, "DS-CDMA Satellite Diversity Reception for Personal Satellite Communication: Downlink Performance Analysis", International Mobile Satellite Conference 1995, Ottawa, Canada, June 6-8, 1995, JPL Publication 95-12, pp. 463-468.

[C16] R. De Gaudenzi, F. Giannetti, M. Luise,"User Recognition and Signature Code Acquisition for BL-DS-CDMA Receivers", IEEE ICC 1995, Seattle, Washington, U.S.A., June 18-22, 1995, pp. 1592-1596.

Fast and reliable signal sense and signature code synchronization for Direct-Sequence Spread Spectrum (DS-SS) signals are key issues in the design of the receiver for modern packet Code-Division Multiple Access (CDMA) radio networks; this motivates the study of the signal recognition and code acquisition (SR/CA) scheme we describe in this paper. Specifically, starting form elementary estimation theory criteria, we work out a non-coherent parallel SR/CA algorithm that is easily suited to a low-complexity full-digital implementation, possibly in a single Application-Specific Integrated Circuit (ASIC). The results of a theoretical analysis of such a scheme, encompassing Additive White Gaussian Noise (AWGN) and Multiple Access Interference (MAI), are integrated and validated by an overall time-domain system simulation. We also evaluate through a simplified approach the impact of some degradation factors on the overall circuit performance, namely sampling epoch and carrier frequency offset, and one-bit signal quantization, to allow optimization of the design parameters as a function of the characteristics of the received signal.

[C17] R. De Gaudenzi, F. Giannetti, M. Luise,"Blind Adaptive Interference Cancellation Detectors for DS/SS CDMA: Algorithms and Performance", 7th Tyrrhenian International Workshop on Digital Communications, Viareggio, Italy, September 10-14, 1995, published by Springer-Verlag, London, United Kingdom, 1996, pp. 53-67.

Code Division Multiple Access (CDMA) has emerged as a strong candidate for the air interface of the universal wireless personal communication system planned for the end of the century. In the latest years, a huge research effort has thus been devoted to find new viable techniques to increase the capacity of CDMA radio networks. In particular, different methods to counteract the near-far effect and todiminish the influence of asynchronous Multiple-Access Interference (MAI) have been investigated with the ambition to make CDMA competitive vis-a-vis more conventional access techniques. In this paper, we take into consideration a recently-proposed low-complexity Blind Adaptive Interference-rejection Detector (BAID) scheme that minimizes the detrimental effect of the MAI on the Bit-Error Rate (BER) performance of the data demodulator for Direct-Sequence/Spread-Spectrum (DS/SS) signals. Specifically, we describe a few modifications to the original algorithm that make it more suitable to a practical implementation with QPSK-modulated DS/SS signals and asynchronous multiplexing, and we evaluate the performance of such extended detector in the case of coherent and differential signal detection.

[C18] R. De Gaudenzi, F. Giannetti, M. Luise,"Blind Adaptive Interference -Rejection Linear Detectors for CDMA Receivers", IEEE ISSSTA '96, Mainz, Germany, September 22-25, 1996, pp. 1253-1257.

In this paper, we take into consideration a recently-proposed low-complexity Blind Adaptive Interfe-rence-rejection Detector (BAID) scheme that minimizes the detrimental effect of the Multiple Access Interference (MAI) on the Bit-Error Rate (BER) performance of the data demodulator for Direct-Sequence/Spread-Spectrum (DS/SS) signals in CDMA radio networks. Specifically, we describe a few modifications to the original algorithm that make it more suitable to a practical implementation with QPSK-modulated DS/SS signals and asynchronous multiplexing, and we evaluate the performance of such extended detector in the case of both coherent and differential signal detection.

[C19] R. De Gaudenzi, F. Giannetti, M. Luise, "An Advanced Linear Adaptive Interference-Rejection Receiver for CDMA Satellite Communications", 5th International Workshop on Digital Signal Processing Techniques Applied to Space Communications, Sitges, Barcelona, Spain, September 25-27, 1996, ESA publication WPP-119, pp. 11.19-11.31.

One of the leading approaches in the design of efficient receivers for Code-Division Multiple Access radio networks is multi-user/interference-cancelling detection. It is known that interference-resilient detection can be seen as a viable means of increasing the capacity of CDMA transmissions in spite of the presence of asynchronous multiple access interference that limits the performance of standard correlation detectors. At the moment, the main question about interference-resilient receivers is: do they really bring forth the capacity increase they promise on paper, when put at work in a realistic environment? The aim of this paper is to give a preliminary answer to such a question, by studying the case of a multi-satellite, multi-beam forward link communication network at S-band. Specifically, starting from simplified assumptions on the beam layout, the antenna footprint shape, and the coding/multiplexing/modulation scheme, it is shown that a particular interference-cancelling receiver, namely the so-called E-BAID introduced by Honig, Madhow and Verdu and refined by the authors, can indeed yield a performance boost to the system quality of service in terms of average outage probability. The results are derived after a mix of theoretical analysis (as far as the detector performance is concerned) and simulation (to examine a number of different random system configurations) to circumvent the inherent complexity of the issue.

[C20] R. De Gaudenzi, F. Giannetti, M. Luise,"How Can Interference-Rejection Receivers Increase the Capacity of CDMA Multi-Beam Satellite Communication Systems?", 2nd European Workshop on Mobile/Personal Satcoms, Rome, Italy, October 9-11, 1996, pp. 349-365.

One of the leading approaches in the design of efficient receivers for Code-Division Multiple Access radio networks is multi-user/interference-cancelling detection. It is known that interference-resilient detection can be seen as a viable means of increasing the capacity of CDMA transmissions in spite of the presence of asynchronous multiple access interference that limits the performance of standard correlation detectors. At the moment, the main question about interference-resilient receivers is: do they really bring forth the capacity increase they promise on paper, when put at work in a realistic environment? The aim of this paper is to give a preliminary answer to such a question, by studying the case of a multi-satellite, multi-beam forward link communication network at S-band. Specifically, starting from simplified assumptions on the beam layout, the antenna footprint shape, and the coding/multiplexing/modulation scheme, it is shown that a particular interference-cancelling receiver, namely the so-called E-BAID introduced by Honig and Verdu and refined by the authors can indeed yield a performance boost to the system quality of service in terms of average outage probability. The results are derived after a mix of theoretical analysis (as far as the detector performance is concerned) and simulation (to examine a number of different random system configurations) to circumvent the inherent complexity of the issue.

[C21] F. Giannetti, M. Luise, R. Reggiannini, "Robust CDMA Radio Transmission over Fading Channels", IEEE GLOBECOM 1996, London, England, November 18-22, 1996, pp. 1311-1315.

[C22] F. Giannetti, M. Luise, R. Reggiannini, "The Capacity of Cellular CDMA in the 63-64 GHz Band", IEEE ICC 1997, Montreal, Canada, June 8-12, 1997, pp. 989-993.

We analyze a cellular asynchronous code-division multiple access (A-CDMA) system operating in the 63-64 GHz band for short-range communications. A simple propagation model for the 63-64 GHz band is first introduced and discussed. The system capacity, expressed as the maximum number of users per cell, is then analytically derived and favorably compared with other CDMA schemes operating in conventional frequency bands (i. e. below 2 GHz). Also, simple expressions for the system bit error rate (BER) are analytically derived for different cases and validated through computer simulations. Finally, power requirements are derived and the impact of atmospheric conditions is evaluated. It turns out that the use of 63-64 GHz band significantly increases the capacity of A-CDMA, and proves to be suitable for cellular systems and personal communication networks (PCNs) provided that adequate power margins are taken into account.

[C23] R. De Gaudenzi, F. Giannetti, M. Luise, "The Capacity of a CDMA Multibeam Satellite System with Interference-Cancellling Receivers", IEEE ICC 1997, Montreal, Canada, June 8-12, 1997, pp. 674-678.

Multi-user/interference-cancelling detection is a viable means of increasing the capacity of CDMA transmissions. The aim of this contribution is to possibly show how the application of such technique may increase the capacity of the forward link of a multi-satellite, multi-beam radio network at S-band. Starting from simplified assumptions on the beam layout, the antenna footprint shape, and the coding/multiplexing/modulation scheme, it is shown that a simple adaptive interference-cancelling receiver can indeed yield a performance boost to the system quality of service in terms of average outage probability.

[C24] F. Giannetti, "Capacity of Broadband CDMA in the Millimeter-Wave Band", 9th Tyrrhenian International Workshop on Digital Communications, Lerici, Italy, September 7-10, 1997, published by Springer-Verlag, London, United Kingdom, 1998, pp. 287-292.

A cellular code-division multiple access (CDMA) system operating in the 63-64 GHz band for short-range communications is studied and analyzed. The system capacity, expressed as the maximum number of users per cell, is analytically derived and favorably compared with other CDMA schemes operating in conventional frequency bands (i.e. below 2 GHz). It turns out that the use of 63-64 GHz band significantly increases the capacity of a CDMA network, and proves to be suitable for cellular systems, personal communication networks (PCNs) and wireless broadband access (ISDN).

[C25] R. De Gaudenzi, F. Giannetti, M. Luise, J. Romero-Garcia,"A Frequency Error Resistant Blind Interference-Mitigating CDMA Detector", IEEE ISSSTA 1998, Sun City, South Africa, September 2-4, 1998, pp. 858-862.

This paper presents an enhanced version of the recently-proposed Blind Adaptive Interference Detector (BAID) for Direct-Sequence Code Division Multiple Access (DS-CDMA) transmission. Such a new detector, named Extended Complex BAID (EC-BAID), reveals resistant to a possible large frequency shift (e.g., Doppler shift) on interfering carriers, and features invariance to a phase error on the useful channel's carrier. The EC-BAID is also shown to bear a sensitivity to residual carrier frequency errors on the desired channel which is lower by three order of magnitude with respect to the Data-Aided Minimum Mean Square Error (DA-MMSE) receiver. The performance of the EC-BAID was numerically assessed by computer simulations and successfully compared to analytical findings under a variety of system configurations. It turned out that the EC-BAID, despite its blind operating mode, bears an uncoded symbol error rate (SER) performance that closely approaches DA-MMSE's. Finally, a few implementation aspects of the new interference-mitigating detector are also discussed.

[C26] R. De Gaudenzi, F. Giannetti, M. Luise, J. Romero-Garcia,"A Frequency Error Resistant Blind Interference-Mitigating CDMA Detector", 6th International Workshop on Digital Signal Processing Techniques Applied to Space Communications, Noordwijk, The Neteherlands, September 23-25, 1998, paper 2.1.

[C27] R. De Gaudenzi, F. Giannetti, M. Luise, J. Romero-Garcia, "New Results on Blind Interference-Mitigating CDMA Detection", URSI ISSSE 1998, Pisa, Italy, September 29-October 2, 1998, pp. 411-415.

[C28] R. De Gaudenzi, F. Giannetti, E. Letta, M. Luise, L. Fanucci, "A Single Chip CDMA Blind Adaptive Interference- Mitigating Detector for Space Applications", 19th AIAA International Communications Satellite Systems Conference, Toulouse, France, April 17-20, 2001, Session No. 19, Paper No. 154.

This paper presents the design and the main performance results of a single-ASIC implementation of the recently-proposed Extended Complex Blind Anchored Interference-mitigating Detector (EC-BAID) for Code Division Multiple Access (CDMA) transmission. Such a detector, which exhibits a remarkable robustness to multiple access interference, operates in blind mode, i.e., it only requires knowledge of the timing of the wanted user's signature code, and it is therefore very well suited for integration into hand-held single-user terminal demodulators for third generation (3G) satcoms. The implementation of the interference-mitigating detector is based on a patented optimized architecture which leads, in 0.25 um CMOS technology, to a roughly 25 Kgate plus 23 Kbit RAM single-chip ASIC supporting chip-rates up to 4 Mchip/s with a maximum internal clock frequency of 32.768 MHz.

[C29] L. Fanucci, E. Letta, M. Rovini. G. Colleoni, R. De Gaudenzi, F. Giannetti, M. Luise, "A Multi-Rate Real-Time Test-Bed for Low-Complexity Adaptive Interference Mitigation in CDMA Transmission", 7th International Workshop on Digital Signal Processing Techniques Applied to Space Communications, Sesimbra, Portugal, October 1-3, 2001, ESA publication WPP-190, paper 6.6.

This paper presents the design and the main performance results of a test-bed for a Code Division Multiple Access (CDMA) digital modem with linear adaptive interference-mitigating detection (IMD) and supporting multi-rate transmission. The aim of this experiment is to demonstrate the suitability of such a receiver architecture, including IMD, to integration into a hand-held user terminal. The test-bed allows for real-time testing of a complete digital CDMA transmission chain, featuring the recently proposed Extended Complex-valued Blind Adaptive Interference-mitigating Detector (EC-BAID) for single-user detection of a CDMA signal. Signal plus Multiple Access Interference (MAI) generation is performed via a computer-controlled arbitrary waveform generator, followed by frequency up-conversion to the standard analogue intermediate frequency (IF) 70 MHz, and by Additive White Gaussian Noise injection with the aid of a precision noise generator. Particular emphasis is devoted to the description of all functions ancillary to IMD, such as generation of the MAI, and robust signature code timing acquisition and tracking under heavy user loading. The test-bed is controlled via IEEE488 bus by a master PC with a dedicated control program specially developed in LabVIEW. This allows maximum configuration control flexibility on one side, and easy derivation of performance results in terms of BER (Bit Error Rate), spectral analysis, sync parameters evolution etc. on the other.

[C30] M. Porretta, P. Nepa, G. Manara, F. Giannetti, "Analysis of Subscriber Radio Location Techniques through a Deterministic Propagation Model", Progress in Electromagnetics Research Symposium (PIERS) 2002, Cambridge, Massachusetts, USA, July 1-5, 2002, page 720.

The interest in radio location algorithms originates from need to guarantee emergency services to calls made by mobile phone users; indeed, beginning October 2001, the FCC requires that, in the US, all emergency calls (911) from cellular phones must be located within 125 m in 67% of the time. Nevertheless, the number of applications for location information is growing rapidly: for example, a location-aware service is to connect the Yellow Pages with a map database giving the information about the address of a certain site (hotel, restaurant, museum) in the closeness of user. Furthermore, location information can be very useful for the network operator, especially in Radio Resource Management (RRM) functions, e.g., selection and handover. A radio location system operates by measuring physical quantities related to radio signals traveling between a mobile station and a set of fixed base stations. The received signal is used to estimate the length and/or direction of arrival of radio paths, and the mobile position is derived from geometrical relationships. In particular, radiolocation systems can be implemented that are based on the angle-of-arrival (AOA), the signal strength, the time-of-arrival (TOA), the time-difference-of-arrival (TDOA), or their combinations (James Caffery, Gordon Stuber, "Subscriber location in CDMA cellular networks" IEEE Transactions on Vehicular Technology, vol. 47, no 2, May 1998). In this work, it is shown that a deterministic simulator of the electromagnetic propagation in urban areas can be usefully employed to optimize and validate a subscriber radio location technique for third generation cellular networks. In particular, a fully three-dimensional simulator based on high-frequency ray-techniques has been applied to validate a TOA radio location algorithm which requires the knowledge of the time of arrival delay at three different base stations. For each mobile position, the received signal is evaluated as the summation of ray contributions reaching the base station after reflections or diffractions, so that non-line-of-sight conditions can be suitably accounted for. Contributions up to the third order for reflections from the walls of the buildings have been also included. Diffractions from the edges of buildings are evaluated through approximate dyadic coefficients which are valid for impedance surface models. Moreover, computer graphics algorithms have been used to speed up the ray-tracing procedure. The algorithm has been tested in a Manhattan-like microcellular environment and the performance have been evaluated in terms of the absolute location error. The effects of the time of arrival quantization are also taken into account. Extensive simulations demonstrated that it is possible to achieve a location error with a mean value of 33 m and a standard deviation of about 20 m. A detailed description of the radio location algorithm implemented will be given at the conference. Work is in progress to include into the algorithm other signal parameters, e.g., amplitude and direction of arrival of the signal received at the base stations, with the specific aim of both increase the accuracy of the algorithm and reduce to less than three the number of base stations required.

[C31] F. Giannetti, P. Grassi, G. Manara, P. Nepa, M. Porretta, "Validazione di Algoritmi di Radio-Localizzazione Mediante un Simulatore della Propagazione Elettromagnetica in Aree Urbane", XIV RiNEm, Ancona, Italy, September 16-19, 2002, pp. 512-515.

Radiolocation techniques open the door to efficient emergency services (E-911/112), as well as to a new world of previously unimagined information services (e.g. electronic yellow pages, "where I am" applications, navigation and personalized traffic). In this paper, it is shown that subscriber radio location techniques may be developed, improved and validated through a deterministic electromagnetic propagation model. Indeed, a numerical code which is able to estimate the main signal parameters (field strength, time delay, direction of arrival) represents an interesting alternative to expensive measurement campaigns. Some numerical results relevant to the location accuracy of a TOA (Time of Arrival) algorithm will be shown. They have been obtained by using a fully 3D electromagnetic propagation model based on an inverse ray tracing algorithm.

[C32] M. Porretta, P. Nepa, G. Manara, F. Giannetti, A.H. Aghvami, M. Dohler, "Validation of a Novel Radio Location Technique by a Deterministic Propagation Model", IEEE Antennas and Propagation Society International Symposium 2003, Columbus, USA, June 22-27, 2003, Vol. 1, pp. 81-84.

A radio location system operates by measuring physical quantities related to radio signals traveling between a mobile terminal (MT) and a set of fixed base stations (BSs). In order to reduce the implementation complexity and the signalling overhead, the solution presented makes use of a single BS to locate unmodified MTs. The novel algorithm applies a triangulation technique supported by minimal information about the environment in the BS neighborhood. The proposed algorithm is compatible with the architecture of 3G cellular networks, as it relies on CDMA (code division multiple access) signalling and a BS array antenna for the estimation of the time delay and of the angle of arrival, respectively. Despite its modest implementation complexity, the proposed algorithm can predict the MT position with a fairly good accuracy, as demonstrated by numerical tests performed by resorting to a fully 3D deterministic propagation model developed at the University of Pisa.

[C33] M. Porretta, P. Nepa, G. Manara, F. Giannetti, M. Dohler, B. Allen, A.H. Aghvami, "A novel single base station mobile location algorithm: description and validation using a deterministic propagation model", IEE Fourth International Conference on 3G Mobile Communication Technologies, London, UK, June 25-27, 2003.

The ability to support position location in wireless networks provides network operators with additional value services, as well users with a host of new applications. This includes navigation, localization based services, network management and security applications. This paper presents a novel algorithm that makes use of a single base Station (BS) to locate Mobile Terminals (MTs) in cellular networks, by utilising a triangulation technique supported by minimal information about the environment in the BS neighbourhood. The algorithm is shown to perform well when operating in a microcellular scenario and perfect channel parameter estimation is assumed. Numerical results for several scenarios relating to 3rd generation (3G) microcellular operating parameters are presented using a 3D deterministic channel model.

[C34] M. Porretta, P. Nepa, G. Manara, F. Giannetti, M. Dohler, B. Allen, A.H. Aghvami, "Estimating Position and Velocity of Mobile Terminals in a Microcellular Network Using an Adaptive Linear Regression Setup", IEEE PIMRC 2004, Barcelona, Spain, September 5-8, 2004.

Mobility tracking enables efficient network control and very useful additional services, although accurate online estimations of both the location and the velocity of a mobile user are required. In this paper, we suggest a method of tracing a mobile by subsequently estimating its position through a Single Base Station Positioning method designed for microcells and third generation (3G) wireless communications systems. Raw data are then smoothed through a linear regression setup which adaptively varies its inertia on the basis of the previous observations. This results in a tracking method which is able to estimate both the location and the velocity of a user with a high accuracy, as proven by numerical results performed in different microcellular scenarios.

[C35] M. Porretta, P. Nepa, G. Manara, F. Giannetti, M. Dohler, B. Allen, A.H. Aghvami, "An Adaptive Linear Regression Scheme for Tracking Mobile Users in a Microcellular Network", Wireless Personal Multimedia Communications 2004 (WPMC'04), Abano Terme (Padua), Italy, September 12-15, 2004.

[C36] V. Lottici, F. Giannetti, "A Nonlinear Channel Compensation Technique for MC-CDMA Communications", Wireless Personal Multimedia Communications 2004 (WPMC'04), Abano Terme (Padua), Italy, September 12-15, 2004.

In this paper a novel nonlinear channel compensation technique based on a data predistortion algorithm is illustrated for the forward link of a wireless MC-CDMA transmission. The proposed method consists in a simple iterative procedure according to which the symbol constellations of all the active users are jointly predistorted taking into account the multiple access interference which degrades the performance of each MC-CDMA terminal unit. The relevant performance evaluated by simulation shows an appreciable reduction of the overall loss and a definite robustness against the different methods for the allocations of the user’s signatures.

[C37] F. Giannetti, M. Luise, "Multi-Rate Modem Front-End for High Speed Satellite Data Transmission", Wireless Personal Multimedia Communications 2004 (WPMC'04), Abano Terme (Padua), Italy, September 12-15, 2004.

Modern communication terminals for wireless communications are based on an all-digital architecture wherein the incoming signal undergoes analog-to-digital conversion (ADC) at intermediate frequency (IF) followed by full-digital frequency down-conversion. Moreover, baseband digital signal processing is typically carried out at 2 samples per symbol so that the high-rate digital stream at the ADC output must be decimated down to twice the symbol rate. This paper describes the architecture of a modem for satellite communications featuring a decimating front-end. Particular emphasis is devoted to the adoption of parallel-processing solutions to overcome the inherent speed limitation of a conventional serial architecture, dictated by the technology of the digital devices. We devise herein a decimator architecture yielding a parallelization by a factor of two while bearing the same implementation complexity as the conventional schemes. Analysis and simulation of the parallelized receiver architecture with multi-level turbo-coded signal exhibit a negligible loss due to the digital front end with respect to “ideal” down-conversion and decimation.

[C38] N.A. D’Andrea, F. Giannetti, G. Manara, M. Michelini, P. Nepa, "Un Laboratorio di Telecomunicazioni ed Elettromagnetismo Applicato per Teledidattica", XV RiNEm, Cagliari, Italy, September 13-16, 2004.

This paper describes the implementation of an educational laboratory yielding both remote control of instruments and data acquisition capabilities through a TCP-IP based network. The system consists of a GPIB interface for connecting the instruments to a PC-server, a server-to-client link based on the TCP-IP protocol, and a virtual instrument, available on each PCc-client, developed using the LabVIEW™ software by National Instruments. The system is being used in the Laboratory of Telecommunication and Applied Electromagnetics of the Faculty of Engineering, at the University of Pisa. At the present it can operate with a vector network analyzer, a spectrum analyzer, a digital oscilloscope and a digital communications analyzer.

[C39] F. Giannetti, P. Nepa, M. Michelini, G. Manara, N.A. D’Andrea, "An Educational Laboratory for Telecommunications Engineering Based on TCP/IP Remote Instrument Control", IADAT International Conference on Education e-2005, Biarritz, France, July 7-8, 2005, pp. 180-184. Proceedings published by International Association for the Development and Advances in Technology IADAT, Bilbao, Spain, 2005, ISBN: 84-933971-6-4.

This paper describes the implementation of an educational laboratory yielding both remote control of instruments and data acquisition capabilities, through a TCP/IP based network. The system consists of a GPIB interface for connecting the instruments to a server PC, a server-to-client link based on the TCP/IP protocol, a network of client PCs, and a virtual instrument application, available on each client PC, developed using the LabVIEW(TM) software by National Instruments. The system is used in the Telecommunication and Applied Electromagnetics Laboratory of the Faculty of Engineering, at the University of Pisa, and supports a wide set of instruments for measurements on communication equipments and microwave devices.

[C40] V. Lottici, F. Giannetti, "Iterative Nonlinear Channel Compensation in MC-CDMA Systems", Fifth International Workshop on Multi-Carrier Spread Spectrum (MC-SS 2005), Oberpfaffenhofen, Germany, September 14-16, 2005, published by Springer, Dordrecht, The Netherlands, 2006, pp. 461-472.

In this contribution we present an efficient multi-user data predistortion algorithm for the compensation of the nonlinear channel in the forward link of a wireless multiple access MC-CDMA system. A simplified method which eases the implementation of the iterative procedure by trading off performance and complexity is also described. Furthermore, we demonstrate that the performance of the proposed compensation scheme can be improved by combining it with a judicious allocation of the spreading signature codes. Computer simulations evidence a significantly better performance with respect to a conventional memoryless pre-distortion technique.

[C41] F. Giannetti, P. Nepa, N.A. D'Andrea, G. Manara, "Coverage Prediction of Cellular MC-CDMA Using a Deterministic Propagation Model", Wireless Personal Multimedia Communications 2005 (WPMC'05), Aalborg, Denmark, September 18-22, 2005, Paper No. 1051.

In this paper cell coverage prediction for a MC-CDMA cellular system is obtained by using an integrated simulation environment developed at the University of Pisa. The simulation environment consists of a propagation tool, developed by the Applied Electromagnetics Research Group, plus a physical layer simulator of MC-CDMA radio links, developed by the Communication System Research Group. The propagation tool features a fully 3D deterministic model based on an inverse ray tracing algorithm, wherein at every observation point the electromagnetic field is given by the vectorial sum of several ray contributions. The multipath propagation parameters are subsequently handled to the transmission physical layer simulator which derives BER performance at the various locations within the cell area, providing accurate radio coverage predictions.

[C42] F. Giannetti, N.A. D'Andrea, "Capacity Evaluation of Cellular MC-CDMA", Wireless Personal Multimedia Communications 2005 (WPMC'05), Aalborg, Denmark, September 18-22, 2005, Paper No. 1055.

In this paper, the down-link of a cellular Multi-Carrier Code-Division Multiple-Access system is considered and investigated in order to derive a quantitative assessment of the impact of multiple-access interference on system performance. The relevant performance figures are expressed in terms of signal quality (i.e., bit error rate) and capacity (i.e., number of users allocated per cell), and are evaluated for a variety of system configurations including power control and interference cancellation.

[C43] V. Lottici, F. Giannetti, "A Novel Adaptive Digital Predistortion Scheme for MC-CDMA Systems", Wireless Personal Multimedia Communications 2005 (WPMC'05), Aalborg, Denmark, September 18-22, 2005, Paper No. 1050.

In this paper we present an efficient scheme employing a multi-user data predistortion algorithm for compensation of the nonlinear channel in the forward link of a wireless multiple access MC-CDMA system. The signal constellations of all the active users are jointly and iteratively optimized by taking into account the multiple access interference degrading the performance at the relevant decision devices. A simplified method is described which makes the iterative procedure simple to implement and enables to trade off performance and complexity. It is shown through simulation that higher performance are achieved with respect to a conventional memoryless predistortion technique.

[C44] A. D'Andrea, F. Giannetti, M. Michelini, "Software Didattico Sviluppato in Ambiente NI LabVIEW per Emulazione di Sistemi di Comunicazione", (in Italian) Forum Tecnologico sulla Strumentazione Virtuale - NIDays 2006, Milan, Italy, February 23, 2006, pp. 134-135.

Un gruppo di docenti del Corso di Studio in Ingegneria delle Telecomunicazioni dell’Università di Pisa ha utilizzato l’ambiente di sviluppo LabVIEW per realizzare una serie di applicativi didattici interattivi per l’emulazione software di sistemi di comunicazione. Tali applicativi sono basati su strumentazione virtuale e riproducono in modo estremamente fedele le funzionalità di strumenti per misure su apparati di telecomunicazione, consentendo agli studenti lo svolgimento delle esercitazioni sperimentali degli insegnamenti professionalizzanti. Gli applicativi possono essere usati sia nell’aula didattica attrezzata, sotto la supervisione del docente, che a casa, tramite CD.

[C45] G. Tiberi, S. Bertini, A. Monorchio, F. Giannetti, G. Manara, "Modeling realistic wide-band indoor propagation channels by using an efficient ray-tracing simulator", IEEE International Symposium on Antennas and Propagation 2006, July 9-14, 2006, Albuquerque, New Mexico, USA.

Recent years witnessed a rapid development of wireless communication systems within buildings. Meanwhile, the increasing demand for high speed data and multimedia services has boosted the research interest in wide-band applications. In such a framework, the investigation of the indoor wide-band propagation channel represents a fundamental step towards the practical implementation of such novel applications. To date, ray tracing (RT) based approaches have been widely used to characterize the indoor channel, for both narrow-band and wide-band systems [1,2,3]. Usually, the wide-band parameters are extracted by properly filtering the RT output at the carrier frequency in order to reproduce the actual bandwidth of the transmitted signal. Obviously this procedure gets less accurate as the bandwidth grows, being the phenomena of reflection, transmission and scattering heavily dependent on the frequency. In this paper, we propose a novel procedure to extract the wide-band propagation channel parameters, that employs a RT simulation carried out at different frequencies followed by a proper processing of the simulated data. An excellent agreement between simulation results and measured data is also shown. The aim of this work is to provide a RT-based tool which can be successfully used for accurate and reliable site-planning in wide-band wireless systems.

[C46] F. Giannetti, V. Lottici, I. Stupia, "Performance Analysis of a MC-CDMA Forward Link over Nonlinear Channels", EUSIPCO 2006, September 4-8, 2006, Florence, Italy.

This paper presents an analytical framework for the performance evaluation of an MC-CDMA forward-link in the presence of nonlinear distortions induced by transmitter's high-power amplifiers. The statistical characterization of the decision variable used for data detection is carried out through the application of the Bussgang theorem. Simulation results validate the accuracy of the proposed method under typical operating conditions.

[C47] F. Giannetti, V. Lottici, I. Stupia, "Iterative Nonlinear Channel Compensation for MC-CDMA Satellite Transmissions", 9th International Workshop on Signal Processing for Space Communications - SPSC 2006, 11-13 September 2006, ESA/ESTEC, Noordwijk, The Netherlands.

In this paper we illustrate an efficient iterative multi-user predistorter scheme for the down-link of a satellite multiple access MC-CDMA which mitigates the nonlinear distortions induced by the power amplifier. Simulation results demonstrate that the proposed scheme can significantly improve the power efficiency of the satellite link.

[C48] F. Giannetti, V. Lottici, I. Stupia, "Theoretical Characterization of Nonlinear Distortion Noise in MC-CDMA Transmissions", PIMRC 2006, September 11-14, 2006, Helsinki, Finland.

This paper presents an analytical framework for the theoretical characterization and performance evaluation of an MC-CDMA forward-link in the presence of nonlinear distortions induced by transmitter's high-power amplifiers. The analytical characterization of the signal features, both in the time and frequency domains, is carried out through the application of the Bussgang theorem. Simulation results are derived to validate the accuracy of the proposed method under typical operating conditions.

[C49] F. Giannetti, V. Lottici, I. Stupia, "Minimum-PAPR Waveform Design for MC-CDMA Transmissions over Nonlinear Channels", Third International Waveform Diversity and Design Conference, June 4-8, 2007, Pisa, Italy.

In this contribution we demonstrate that the peak-to-average power ratio (PAPR) of a Multi-Carrier Code Division Multiple Access (MC-CDMA) signal can be suitably minimized by resorting to a judicious strategy for the allocation of the spreading signature codes. A low-complexity implementation of the proposed strategy is presented and its performance gain over conventional random allocation strategy is numerically assessed.

[C50] F. Giannetti, V. Lottici, I. Stupia, L. Vandendorpe, "A Low-Complexity Spreading-Code Allocation Strategy for Reduced-PAPR MC-CDMA Transmissions", 16th IST Mobile and Wireless Communications Summit, July 1-5, 2007, Budapest, Hungary.

[C51] I. Stupia, L. Vandendorpe, J. Louveaux, F. Giannetti, V. Lottici, N.A. D'Andrea, "Power Allocation for Goodput Optimization in BICM-OFDM systems", IEEE ICC 2008, May 19-23, 2008, Beijing, P.R. China, pp. 3604-3608.

This paper deals with the power allocation problem for coded multicarrier transmission. Specifically, we focus on a bit interleaved coded modulation (BICM) packet transmission implemented with Orthogonal Frequency Division Multiplexing (OFDM) and in the presence of automatic repeat request (ARQ) protocol. Capitalizing on the binary-input output-symmetric (BIOS) nature of the BICM channel it is provided a simple upper-bound of the rate of information bits received without any error, the so called goodput. Based on this theoretical characterization, we develop a power allocation strategy among the different subcarriers so that the system goodput performance metric is maximized. The effectiveness of the proposed method is numerically testified for BICM-OFDM transmission in the context of the typical WLAN scenario.

[C52] I. Stupia, L. Vandendorpe, J. Louveaux, F. Giannetti, V. Lottici, N.A. D'Andrea, "Optimum Goodput-Oriented Power Allocation Policy for BIC-OFDM Packet Transmissions", IEEE ISSSTA 2008, August 25-28, 2008, Bologna, Italy.

In this contribution we study the optimal power allocation scheme for a coded multicarrier transmission. Specifically, we focus on a bit interleaved coded modulation (BICM) packet transmission implemented with Orthogonal Frequency Division Multiplexing (OFDM) and in the presence of automatic repeat request (ARQ) protocol. Based on a simple lower-bound of the rate of information bits received without any error, the so called goodput, we develop a power allocation strategy among the different subcarriers so that the system goodput performance metric is maximized. We also demonstrate the optimality of the solution for the proposed objective function under the given power constraint. The effectiveness of the power allocation policy is numerically testified for BIC-OFDM transmission in the context of typical indoor environment.

[C53] I. Stupia, F. Giannetti, V. Lottici, L. Vandendorpe, J. Louveaux, "Power and Bit Allocation for Goodput Optimization in BIC-OFDM Systems", IEEE PIMRC 2008, September 15-18, 2008, Cannes, France.

This paper contributes with an adaptive modulation scheme intended for bit interleaved coded (BIC) orthogonal frequency division multiplexing (OFDM) packet transmission in the presence of automatic repeat request (ARQ) protocol. The basic idea consists in properly combining the power allocation strategy with a bit-loading procedure among the different subcarriers so that the rate of information bits received without any error is maximized. Numerical simulations corroborate the effectiveness of the proposed scheme when operating over typical wireless environments.

[C54] I. Stupia, F. Giannetti, V. Lottici, L. Vandendorpe, "An Alternative Efficient Approach to Link Error Prediction", NEWCOM++ Dissemination Day, March 31, 2009, Barcelona, Spain.

Coded multicarrier techniques combined together with link resources adaptation algorithms are the key technologies toward efficient high data-rate communications over wireless fading channels. This work contributes with a novel accurate yet simple method to predict the link performance of bit-interleaved coded (BIC) orthogonal frequency division multiplexing (OFDM) links, which offers appealing features when compared with conventional techniques. Its effectiveness is confirmed through extensive simulation results obtained over typical wireless channel environments.

[C55] I. Stupia, F. Giannetti, V. Lottici, L. Vandendorpe, "Futher Results on Link Performance Prediction for Coded Multi-Antenna OFDM Systems", NEWCOM++ - ACoRN Joint Workshop, April 1st, 2009, Barcelona, Spain.

An efficient and flexible air interface is the necessary condition to achieve the high data rate required from the next generation wireless systems. Coded multi-antenna and multicarrier techniques combined together with link resources adaptation algorithms are a practical answer to this need. The practicability of this concept, however, requires that the transmitter can perform accurate and simple evaluation of the actual link performance. This paper contributes to this issue with a novel method specifically developed to predict the link performance of bit-interleaved coded MIMO-OFDM links, which offers improved accuracy with the same degree of complexity when compared with conventional techniques. Its effectiveness is confirmed through extensive simulation results obtained over typical wireless channel environments.

[C56] I. Stupia, F. Giannetti, V. Lottici, L. Vandendorpe, "A Novel Link Performance Prediction Method for Coded MIMO-OFDM Systems", IEEE WCNC 2009, April 5-8, 2009, Budapest, Hungary.

Coded multi-antenna and multi-carrier techniques combined together with link resources adaptation algorithms are the key technologies toward efficient high-data-rate communications over wireless fading channels. The practicability of this concept, however, requires that the transmitter can perform accurate and simple evaluation of the actual link performance. This paper contributes with a novel method specifically developed to predict the link performance of bit-interleaved coded MIMOOFDM links, which offers improved accuracy at the price of lower complexity when compared with conventional techniques. Its effectiveness is confirmed through extensive simulation results obtained over typical wireless channel environments.

[C57] F. Giannetti, V. Lottici, I. Stupia, N.A. D'Andrea, "Reduced-PAPR Code Allocation Strategy for MC-CDMA Transmissions", Multi-Carrier Systems and Solutions 2009 (MC-SS 2009), May 5-6, 2009, Herrsching, Germany. Lecture Notes in Electrical Engineering (LNEE), Vol. 41, 2009, pp. 227-236 - Spinger Verlag, ISSN 1876-1100.

First, an approximate expression for the peak-to-average power ratio (PAPR) of a multi-carrier code-division multiple access (MC-CDMA) signal is analytically derived. Then, it is demonstrated that the PAPR of a MC-CDMA signal can be suitably reduced by resorting to a judi- cious strategy for the allocation of the signature codes. Based on such a result, a low-complexity implementation of the proposed strategy is presented and its performance gain over the random allocation strategy is numerically assessed in terms of PAPR and out-of-band emissions.

[C58] I. Stupia, F. Giannetti, V. Lottici, L. Vandendorpe, "A Novel Exponential Link Error Prediction Method for OFDM Systems", Multi-Carrier Systems and Solutions 2009 (MC-SS 2009), May 5-6, 2009, Herrsching, Germany. Lecture Notes in Electrical Engineering (LNEE), Vol. 41, 2009, pp. 291-300 - Spinger Verlag, ISSN 1876-1100.

Coded multicarrier techniques combined together with link resources adaptation algorithms are the key technologies toward efficient high- data-rate communications over wireless fading channels. This paper contributes with a novel accurate yet simple method to predict at the transmitter the link performance of bit-interleaved coded (BIC) orthog- onal frequency division multiplexing (OFDM) links, which offers ap- pealing features when compared with conventional techniques. Its ef- fectiveness is confirmed through extensive simulation results obtained over typical wireless channel environments.

[C59] F. Giannetti, M. Michelini, N.A. D'Andrea, "Instruments Go Virtual: Experiences on Educational Activities in the Field of Telecommunications at the University of Pisa", Worhshop III "Towards Improving the Engineering Education" under the European Comission project Tempus JEP - 41112 - 2006, Nis, Serbia, June 5-6, 2009.

[C60] I. Stupia, F. Giannetti, V. Lottici, L. Vandendorpe, J. Louveaux, "BICMB-OFDM Link Resource Adaptation", IEEE ICC'09, June 14-18, 2009, Dresden, Germany.

An efficient and flexible air interface is the necessary condition for enabling high data rates next generation wireless systems. A practical answer to this need consists in exploiting channel state information at the transmitter for an adaptive and efficient use of the available radio link resources. This paper contributes with a novel strategy for the allocation of the subcarrier transmit power in the case of a wireless system featuring: i) bit-interleaved coded modulation (BICM); ii) orthogonal frequency division multiplexing (OFDM); iii) multiple antenna profile (MIMO). The proposed power-allocation algorithm aims at maximizing the so-called goodput performance metric for packet transmissions employing automatic repeat request (ARQ) schemes. In addition, it is also proven to be near-optimum in maximizing the input/output mutual information of the MIMOOFDM subchannels. Numerical simulations over typical wireless indoor scenarios confirm the effectiveness of the procedure when applied in the context of MIMO-BICM-OFDM systems.

[C61] I. Stupia, F. Giannetti, V. Lottici, L. Vandendorpe, "A Greedy Algorithm for Goodput-Based Adaptive Modulation and Coding in BIC-OFDM Systems", European Wireless 2010, April 12-15, 2010, Lucca, Italy.

This paper develops cross-layer adaptive modulation and coding as an efficient method for bit interleaved coded OFDM packet transmission. As objective function, we adopt the goodput, or the number of data bits delivered without error per unit of time. After the formalization of the optimization problem through an accurate modeling on the link performance, an iterative solution is derived based on the framework of greedy algorithms. Simulation results show that the proposed method improves upon the performance of static transmission and uniform bit allocation by 2-4 dB.

[C62] I. Stupia, F. Giannetti, V. Lottici, R. Andreotti, L. Vandendorpe, N.A. D'Andrea, "A Greedy Algorithm for Goodput-Oriented AMC in Turbo-Coded OFDM", Future Network & Mobile Summit (FUNEMS) 2010, June 16-18, 2010, Florence, Italy.

This paper presents a novel technique for cross-layer adaptive modulation and coding, suited for bit interleaved turbo-coded OFDM packet transmission, and aimed at maximizing the goodput (i.e., the number of data bits delivered without error per unit of time). The optimization problem is formalized through an accurate modeling on the link performance, and a greedy iterative solution is derived. Simulation results demonstrate that performance improvement provided by the proposed method amount to 4 dB with respect to static transmission and about 1.2 dB with respect to adaptive transmission with uniform bit allocation.

[C63] I. Dagres, A. Zalonis, A. Polydoros, I. Stupia, F. Giannetti, V. Lottici, A. Kliks, "AMC Design Based on Effective SNR Mapping techniques for Multi-Carrier Systems", (poster) Future Network & Mobile Summit (FUNEMS) 2010, June 16-18, 2010, Florence, Italy.

[C64] R. Andreotti, I. Stupia, F. Giannetti, V. Lottici, L. Vandendorpe, "Resource Allocation in OFDMA Underlay Cognitive Radio Systems Based on Ant Colony Optimization", (poster) Future Network & Mobile Summit (FUNEMS) 2010, June 16-18, 2010, Florence, Italy.

[C65] R. Andreotti, I. Stupia, F. Giannetti, V. Lottici, L. Vandendorpe, "Resource Allocation in OFDMA Underlay Cognitive Radio Systems Based on Ant Colony Optimization", SPAWC 2010, June 20-23, 2010, Marrakesh, Morocco.

This paper deals with dynamic resource allocation problem for OFDMA-based cognitive radio systems. The proposed solution is specifically tailored for a secondary base stations (SBS) transmitting to secondary users (SUs) over the same bands of the licensed primary users (PUs) in underlay fashion. The downlink transmission goodput is thereby maximized while keeping the interference on the PUs within a tolerable range. The NP-hard goodput maximization problem is tackled resorting to an efficient meta-heuristic algorithm based on Ant Colony Optimization (ACO) framework.

[C66] R. Andreotti, F. Giannetti, V. Lottici, I. Stupia, L. Vandendorpe, "Resource Allocation in OFDMA Cognitive Radio Systems Based on Ant Colony Optimization", COST2100 and IC0902 Joint Workshop, November 23-25, 2010, Bologna, Italy.

Traditional spectrum management, in order to guarantee the coexistence of the various wireless services, assigns prescribed and fixed frequency bands to licensed users, or, primary users (PUs). Anyway these portions of spectrum are not at all time and in all locations used by PUs, as pointed out by measurements conducted by the Federal Communication Commission. This leads to an inefficient utilization of these bands, creating however an opportunity for unlicensed (secondary) users (SUs) that wish to transmit opportunistically over those bands. To this goal, Mitola, in 1999, proposed the concept of cognitive radio (CR), a device able to sense the environment, find the portions of spectrum temporarily left free by PUs and transmit over them. The proposed work copes with the resource allocation (RA) problem for the downlink of a cognitive secondary base station (SBS) which transmits to its secondary receivers over the licensed frequencies of the PUs, keeping the interference caused to the PUs below a certain threshold called interference temperature. In order to exploit these spectrum opportunities, a CR device needs a highly flexible physical layer, allowing it to adapt its transmission parameters (e.g. modulation order, coding size, power, etc.) to the network conditions. For these reasons, the considered SBS is a bit interleaved coded OFDMA (BIC-OFDMA) system. The multi-channel OFDM(A) modulation allows an efficient transmission over wireless selective channels and the BICM scheme offers a further robustness increase against the harsh propagation conditions of wireless channels. Recently, a huge number of works has been devoted to the problem of managing resources in underlay CR, exploiting different approaches, as for instance capacity maximization, subject to interference power constraints. The Shannon capacity, however, to be achievable, requires independent Gaussian inputs across parallel subchannels and perfect Shannon code knowledge. In practice, it results unfeasible and, for this reason, this work considers an objective function entailing practical modulation and coding schemes, as M-QAM modulation and turbo codes. Moreover the presence of the ARQ retransmission mechanism at the data link layer is taken into account in order to quantify the trade-off between data rate and link reliability. To this goal, a significant figure of metric has been detected in the offered layer 3 data rate, or goodput (GP) for short. Considering the scenario described above, the RA problem at the SBS results in finding how to jointly allocate bits and subcarriers to each secondary user in order to maximize the overall goodput realized by the system. Unfortunately, this problem has a NP-hard complexity. Thus, after a proper analysis of the goodput function, we tackled the RA problem resorting to the Ant Colony Optimization framework, which offers a valid set of tools to solve this kind of combinatorial optimization problems. The proposed algorithm, named max-sum goodput (MSG), is compared with other pragmatic algorithms bearing the same complexity and simulation results show how the MSG can remarkably boost GP performance.

[C67] F. Giannetti, I. Stupia, V. Lottici, R. Andreotti, L. Vandendorpe, "Trading-off Troughput vs. Energy in Adaptive BIC-OFDM over Nonlinear Channels: a Novel Approach", NEWCOM++ / COST 2100 Joint Workshop on Wireless Communications, March 1-2, 2011, Paris, France.

This paper presents an accurate tool yielding a reliable prediction of the link quality for the down-link of a BICOFDM system featuring bandlimited pulse shaping to control spectral sidelobe emission, plus AMC, and operating over a nonlinear channel. The tool enables an effective design of the communication system, with special respect to the setting of the operating point of the transmitter's power amplifier. First, an analytical characterization of the nonlinear distortion effects caused by the amplifier on bandlimited BIC-OFDM signals is carried out by resorting to the extended version of the Bussgang theorem. Then, after a survey of some link quality prediction methods, the equivalent additive noise model provided by the Bussgang-based analysis is taken into account in the derivation of a novel method, named B??ESM. Finally, the novel B??ESM tool is employed in the link design phase for choosing the best amplifier setting, aimed at maximizing the layer-3 offered traffic over a realistic wireless channel, featuring both multipath propagation and nonlinear distortions.

[C68] A. Kliks, I. Stupia, V. Lottici, F. Giannetti, F. Bader, "Generalized Multi-Carrier: an Efficient Platform for Cognitive Wireless Applications", Multi-Carrier Systems and Solutions 2011 (MC-SS 2011), May 3-4, 2011, Herrsching, Germany.

In this paper the Generalized Multicarrier (GMC) based transmission has been proposed as a candidate for wireless cognitive applications. It has been proved that by relaxing the constraints typical for OFDM transmission (such as fixed time and frequency distance between the transmit pulses) one can gain not only in terms of spectral efficiency but also in terms of lower out-of-band radiation. Moreover, it has been proposed to solve one of the main problems of the GMC signaling, that is the presence of the so-called residual self-interference by means of iterative interference cancellation (IIC) methods. The performance in terms of BER and averaged transmit power of the GMC system has been compared with OFDM one in the presence of the fading channel. In both cases, the pragmatic bit and power loading scheme based on the Campello algorithm have been considered and the IIC based receivers have been tested.

[C69] I. Stupia, R. Andreotti, V. Lottici, F. Giannetti, "Adaptive Hybrid ARQ for Goodput Optimization in BIC-OFDM Systems", Multi-Carrier Systems and Solutions 2011 (MC-SS 2011), May 3-4, 2011, Herrsching, Germany.

In next generation wireless networks, high data rates under strict quality of service (QoS) constraints call for flexible radio interfaces capable of adapting their configuration on the fly to the time-varying operating environment. Motivated by this need, this paper first derives a simple link performance prediction model for bit interleaved coded orthogonal frequency division multiplexing (BIC-OFDM) systems using incremental redundancy (IR) hybrid automatic repeat request (HARQ) mechanisms. Then, an adaptive HARQ strategy is formulated whose aim is maximizing the goodput (GP) metric, i.e., the number of error-free information bits delivered to the user by unit of time, over the coding rate, the bit distribution and an on-off power allocation across the active subchannels. Simulation results corroborate the GP performance gains of the proposed approach compared with non-adaptive transmissions, while keeping the computational complexity at affordable levels.

[C70] F. Giannetti, I. Stupia, V. Lottici, R. Andreotti, N.A. D'Andrea, L. Vandendorpe, "A Performance Prediction Model for BIC-OFDM Transmissions with AMC over Nonlinear Fading Channels", Multi-Carrier Systems and Solutions 2011 (MC-SS 2011), May 3-4, 2011, Herrsching, Germany.

This paper presents an accurate tool yielding a reliable prediction of the link quality for the down-link of a BICOFDM system featuring bandlimited pulse shaping to control spectral sidelobe emission, plus AMC, and operating over a nonlinear channel. The tool enables an effective design of the communication system, with special respect to the setting of the operating point of the transmitter’s power amplifier. First, an analytical characterization of the nonlinear distortion effects caused by the amplifier on bandlimited BIC-OFDM signals is carried out by resorting to the extended version of the Bussgang theorem. Then, the equivalent additive noise model provided by the Bussgang-based analysis is taken into account in the derivation of a novel link quality prediction method, named B??ESM. Finally, the novel B??ESM tool is employed in the link design phase for choosing the best amplifier setting, aimed at maximizing the layer-3 offered traffic over a realistic wireless channel, featuring both multipath propagation and nonlinear distortions.

[C71] R. Andreotti, V. Lottici, F. Giannetti, I. Stupia, L. Vandendorpe, "Optimal and sub-optimal power allocation algorithms for goodput optimization in cognitive multi-channel wireless systems", 32nd WIC Symposium on Information Theory in the Benelux - First joint WIC/IEEE SP Symposium on Information Theory and Signal Processing in the Benelux, May 10-11, 2011, Brussels, Belgium.

This paper studies the power allocation problem for a cognitive wireless system transmitting over multiple parallel channels. The goal of the power allocation is to maximize the total system goodput, or, the offered layer 3 data rate, keeping at the same time the interference caused to the licensed users, which transmit over the same bands of the cognitive device, under the prescribed threshold. This optimization problem results to be convex and then solvable with conventional numerical methods. Due to the high computational time required by these methods, a sub-optimal approach is also proposed, offering a good trade-off between quality of solution and speed of the algorithm.

[C72] D. Francesconi, J. Van Hecke, F. Giannetti, V. Lottici, M. Moeneclaey, "Distributed Dynamic Resource Allocation for Cooperative Cognitive Radio", IEEE WCNC 2012, April 1-4, 2012, Paris, France.

We consider a cognitive radio (CR) scenario where the signals transmitted by a secondary user are relayed using an amplify-and forward cooperation protocol. A distributed strategy for power allocation is derived that minimizes the outage probability of the cooperative CR communication system, under the constraint that the interference power experienced by the primary receiver does not exceed a given threshold. First, assuming that each CR node has ideal channel state information about its interference channel, we show that the average interference power constraint gives better outage probability performance than the peak power constraint. Then, when only channel statistics are available for the interference channel, the outage probability is verified to lie in between the results relevant to the average and peak power constraints, respectively, with ideal channel state information.

[C73] R. Andreotti, V. Lottici, F. Giannetti, I. Stupia, L. Vandendorpe, "A Game Theoretical Approach for Reliable Packet Transmission in Noncooperative BIC-OFDM Systems", IEEE ICC'13, June 9-13, 2013, Budapest, Hungary.

In this work, we investigate the power allocation (PA) problem aimed at minimizing the users' packet error rate (PER) over a noncooperative link, i.e., a link where the set of users, employing packet-oriented BIC-OFDM systems, compete for the same bandwidth. For these kind of systems, the PER is not available in closed-form, but a very efficient solution is offered by the effective SNR mapping (ESM) technique. This method allows each user to evaluate a single scalar value, the effective SNR (ESNR), accounting for all the SNIRs experienced over the active subcarriers, and to univocally map it into a PER value. Thus, in order to derive a decentralized strategy allowing each user to minimize its own PER, the problem is described as a strategic game, called min-PER game, with the set of player, utilities and strategies represented by the competitive users, the ESNRs and the set of feasible power allocations, respectively. We will show both the existence of at least one Nash Equilibrium (NE) for the min-PER game and its equivalence with a Nonlinear Variational Inequality (NVI) problem. Finally, relying on the theory of contraction mappings, we will derive a distributed algorithm to reach the NE of the game.

[C74] J. Van Hecke, F. Giannetti, V. Lottici, M. Moeneclaey, "Outage Probability Minimization for Cooperative Cognitive Radio with Best-Relay Selection under an Average Interference Power Constraint", IEEE PIMRC 2013, London, UK, September 8-11, 2013.

In this contribution, a cognitive radio scenario is considered, where a secondary user (SU) cooperative network is allowed to transmit concurrently with a primary user (PU), provided that the resulting average interference power at the PU receiver is kept below a certain threshold. The SU network uses a selection amplify-and-forward protocol. An optimum and a lowcomplexity suboptimum dynamic energy allocation strategy are proposed, that minimize the link outage probability between the source node and the destination node of the SU network under an average interference power constraint. Because the interference channels from the SU nodes to the PU are affected by fast fading, the realistic assumption is made that each SU node has access to the root mean-square value (rather than the instantaneous value) of the gain of its own interference channel to the PU. We show that both dynamic allocation strategies considerably outperform the optimum static allocation strategy, and that the low-complexity dynamic allocation performs nearly as well as the optimum dynamic allocation. Finally, we confirm that our dynamic algorithms show a significant performance improvement as compared to the optimal dynamic algorithm under a peak interference power constraint.

[C75] P. Del Fiorentino, R. Andreotti, V. Lottici, F. Giannetti, J. Van Hecke, M. Moeneclaey, "Link Resource Adaptation for BIC-OFDM Systems with Outdated Channel State Information", European Wireless (EW) Conference 2014, Barcelona, Spain, May 14-16, 2014.

This paper addresses the link resource adaptation (LRA) problem for bit-interleaved coded orthogonal frequency division multiplexing systems when the transmitter makes use of outdated channel state information (CSI). Differently from the capacity-based works recently appeared in the literature, our approach is to optimize the modulation format, coding rate and power distribution across the subcarriers by maximizing the system expected goodput (EGP). The main contributions basically relies on deriving a novel link performance prediction (LPP) method under outdated CSI, based on which an effective LRA strategy is developed. Simulation results corroborate the effectiveness of the proposed method, showing remarkable performance gains compared to the conventional approach which does not care of the outdated CSI.

[C76] P. Del Fiorentino, R. Andreotti, V. Lottici, F. Giannetti, I. Stupia , L. Vandendorpe, "Distributed Power Allocation Based On PER Minimization for Noncooperative Multicarrier Systems Under Interference Constraints", (poster) European Conference on Networks and Communications (EuCNC’2014), Bologna, Italy, June 23-26, 2014.

The cognitive approach, which is a key factor for the reuse available spectrum in wireless networks, enables secondary users (SUs) to share the same band of primary users (PUs) by limiting the interference caused to the latter. Focusing on interference channels, this work develops a distributed power allocation (PA) strategy aimed at minimizing the coded packet error rate (PER) of noncooperative SUs’ links, with the constraint of satisfying the interference limit at PU receivers and considering SUs based on bit-interleaved-coded orthogonal frequency division multiplexing technology. The proposed PA is formulated as a noncooperative game, relaxed by applying a pricing mechanism and solved by an iterative algorithm. Then, given the PA strategy, an adaptive modulation and coding scheme to further improve performance is devised. Finally, numerical simulations show the effectiveness of the proposed algorithms.

[C77] P. Del Fiorentino, R. Andreotti, F. Giannetti, V. Lottici, J. Van Hecke, M. Moeneclaey, "Radio Resource Allocation Algorithms in Cognitive Radio Networks with Outdated CSI", NEWCOM# special session, European Conference on Networks and Communications (EuCNC’2014), Bologna, Italy, June 23-26, 2014.

The presentation will summarize the first two outcomes of the JRA and highlight the open issues currently under investigation. The first part concerns a preliminary work about a link resource adaptation (LRA) problem for point-to-point bit-interleaved coded (BIC) OFDM systems with outdated channel state information (CSI) at the transmitter. The LRA strategy is able to select modulation, coding rate and power distribution of a OFDM system with the aim to maximize the expected goodput (EGP) metric. The main contributions consists in the derivation of a novel link performance prediction (LPP) method under outdated CSI. Based on these findings, an effective LRA strategy is then developed. Simulation results corroborate the effectiveness of the proposed method, showing remarkable performance gains w.r.t. the conventional approach which does not care of the outdated CSI. The main results of this study are reported in a paper to be presented at the forthcoming European Wireless 2014 conference. The second activity deals with a centralized resource allocation problem for multicarrier cooperative cognitive radio networks in the presence of imperfect CSI. The problem considers a cooperative network in a cognitive scenario, in which a secondary user (SU) may gain access to the same bandwidth of a primary user (PU) network, if the interference at the PU receivers is kept below a certain interference threshold. The cooperative network considered in this study includes the source node (SN), the destination node (DN) and M relay nodes (RNs). Direct link is not present between the SN and DN and decode-and-forward protocol is used at RNs. In this scenario, the SN transmits several OFDM symbols to the different RNs. Then each RN decodes the messages of a certain subset of subcarriers, then re-encodes these messages and forwards to the DN them, by using on different subcarriers w.r.t. the SN-RN link. The centralized resource allocation problem selects the subcarrier pairing for the SN-RN and the RN-DN links, and a power allocation for each RN with the aim of keeping the interference at each PU receiver below a certain threshold. Finally, the current research activities on the open issues will be briefly summarized. The goal is to derive a distributed resource allocation problem, by resorting to mathematical theory of convex optimization and game theory, for the scenario described above. The activity will also introduce, as performance metric, the goodput and the packet error rate, which both allow to characterize in more a suitable way the actual performance of a packet-oriented communication system. Moreover, the performance of the SN-RN-DN link will be investigated, in the presence of imperfect CSI.

[C78] R. Andreotti, S. Mijovic , I. Stupia, C. Buratti, F. Giannetti, A. Zanella, "VAA Formation Game for Cooperative Wireless Sensor Networks", European Conference on Networks and Communications (EuCNC’2014), Bologna, Italy, June 23-26, 2014.

In this work we consider a Wireless Sensor Network (WSN), where nodes cooperate to send data to a remote sink. In particular, we assume that sensor nodes form Virtual Antenna Arrrays (VAAs) and use cooperative beamforming to transmit toward the sink. The VAA formation problem is formulated as a noncooperative game with complete information. In fact, on one hand cooperation greatly increases link capacity, but on the other, it introduces a certain overhead. The latter tradeoff is analyzed resorting to a game theoretical approach in which sensor nodes aim at forming VAAs to maximise their own successful transmission rate, while keeping under control the energy consumed for the signaling within VAAs. Based on this analysis, we then introduce a communication protocol for VAA formation. Numerical results show the advantages of cooperation among nodes as well as the impact of considering a realistic communication protocol, accounting for packets losses, with respect to the ideal case achieved through the game.

[C79] J. Van Hecke, P. Del Fiorentino, V. Lottici, M. Moeneclaey, F. Giannetti, "Resource Allocation for Multicarrier Cooperative Cognitive Radio Networks with Imperfect Channel State Information", IEEE PIMRC 2014, September 2-5, 2014, Washinghton DC, USA.

In this paper we consider a decode-and-forward cooperative network, which is active in the same bandwidth as a primary user network. The cooperative or secondary user network applies a dynamic resource allocation algorithm to maximize its own performance while limiting the interference caused at the primary user receivers. The main contribution of this paper is the proposition of a new accurate approximation for the outage probability, which takes into account that the channel state information available at the transmitter is imperfect and outdated. The accuracy of the approximation and the performance of the resource allocation scheme are validated through numerical simulations.

[C80] P. Del Fiorentino, R. Andreotti, V. Lottici, F. Giannetti, I. Stupia, "Distributed Power Allocation for Cognitive Noncooperative BIC-OFDM Systems", ISWCS 2014, August 26-29, 2014, Barcelona, Spain.

The focus of this work is put on a cognitive network wherein the secondary users (SUs), based on bit-interleaved-coded orthogonal frequency division multiplexing, share the same band of primary users (PUs). In this context, we develop a distributed power allocation (PA) strategy which minimizes the coded packet error rate (PER) of the noncooperative SU links under the constraint of satisfying the interference limit at PU receivers. The proposed PA problem is formulated as a noncooperative game, relaxed by applying a pricing mechanism and then solved by an iterative algorithm. On top of the PA strategy, an adaptive modulation and coding scheme is also applied to further boost performance. Numerical simulations show the effectiveness of the proposed algorithms when tested in typical wireless scenarios.

[C81] R. Andreotti, F. Giannetti, M. Luise, "An Energy-Efficient Solution for Packet-Based Transmissions with QoS Constraints in the Multibeam Satellite Downlink", 7th Advanced Satellite Multimedia Systems Conference and 13th Signal Processing for Space Communications Workshop (ASMS/SPSC 2014), Livorno, Italy, September 8-10, 2014.

This paper tackles the issue of boosting the capacity of xDSL networks in the presence of geographical gaps. An effective approach for such a kind of operating scenarios consists in exploiting the downlink of either legacy broadcast or advanced multibeam satellites for the delivering of packed-based traffic. This can be done by resorting to the data link layer protocol named Generic Stream Encapsulation which enables the transport of IP traffic (or any other packet oriented protocol) over the DVB-S2 uni-directional physical layer link. The solution presented in this paper consists first in the derivation of an adaptive coding and modulation (ACM) scheme for such an IP over DVB-S2 system, aimed at maximizing the “goodput” (GP), i.e., the offered layer-3 data rate, net of encapsulation overhead. To this aim, the look-up table for ACM is numerically derived by associating to any signal-to-noise-plus-interference ratio of the satellite downlink, the pair “modulation order/coding rate” yielding the highest value of GP. Then, in case of multibeam coverage, in order to manage the co-channel interference arising from beams exploiting the same band, an adaptive power control is also proposed. The goal of the latter is to maximize the energy-efficiency of the downlink satellite transmission while guaranteeing a given quality-of-service over each link in terms of minimum-GP constraint.

[C82] J. Van Hecke, P. Del Fiorentino, R. Andreotti, V. Lottici, F. Giannetti, L. Vandendorpe, M. Moeneclaey, "Goodput-maximizing Resource Allocation in Cognitive Radio BIC-OFDM systems with DF Relay Selection", IEEE ICC'15, June 8-12, 2015, London, UK.

We propose a novel resource allocation (RA) strategy for a cognitive radio packet-oriented bit-interleaved coded orthogonal frequency division multiplexing (BIC-OFDM) system with decode-and-forward (DF) relays. The aim of the RA is maximizing the goodput (GP) of the source-relay-destination link, which is the number of information bits correctly received at the destination node per unit of time. Therefore, we derive an accurate analytic approximation for this figure of merit, which allows us to find the optimum constellation size, code rate and energy allocation per subcarrier. Further, this expression also serves as a novel relay selection criterion. Finally, we validate the proposed RA method, and compare its performance to capacitymaximizing algorithms through numerical simulations.

[C83] P. Del Fiorentino, J. Van Hecke, V. Lottici, F. Giannetti, M. Moeneclaey, "Goodput-based Resource Allocation and DF Relay Selection for Dual-Hop Transmissions with Packet-oriented Cognitive BIC-OFDM Systems", (poster) Joint NEWCOM/COST Workshop on Wireless Communications JNCW 2015, October 14–15, 2015, Barcelona, Spain.

We propose a novel resource allocation (RA) strategy for a cognitive radio packet-oriented bit-interleaved coded orthogonal frequency division multiplexing (BIC-OFDM) system with decode-and-forward (DF) relays. The aim of the RA is maximizing the goodput (GP) of the source-relay-destination link, which is the number of information bits correctly received at the destination node per unit of time. Therefore, we derive an accurate analytic approximation for this figure of merit, which allows us to find the optimum constellation size, code rate and energy allocation per subcarrier. Further, this expression also serves as a novel relay selection criterion. Finally, we validate the proposed RA method, and compare its performance to capacity-maximizing algorithms through numerical simulations.

[C84] P. Del Fiorentino, J. Van Hecke, V. Lottici, F. Giannetti, M. Moeneclaey, "Radio resource allocation algorithms in cognitive radio networks with outdated CSI", (invited presentation) Joint NEWCOM/COST Workshop on Wireless Communications JNCW 2015, October 14–15, 2015, Barcelona, Spain.

[C85] J. Van Hecke, P. Del Fiorentino, R. Andreotti, V. Lottici, F. Giannetti, L. Vandendorpe, M. Moeneclaey, "Accurate modeling of the predicted kESM-based link performance metric for BIC-OFDM systems," 22nd IEEE Symposium on Communications and Vehicular Technology in the Benelux 2015 (SCVT 2015), Luxembourg, November 24, 2015.

Effective SNR mapping (ESM) is a powerful technique for optimizing the performance of orthogonal frequency division multiplexing (OFDM) based wireless systems. ESM transforms a vector of subcarrier SNRs into a scalar effective SNR, which represents the SNR that would yield the same error performance in an equivalent system operating over an additive white Gaussian noise (AWGN) channel. This technique significantly simplifies the development of adaptive coding and modulation (ACM) algorithms. As the distribution of the effective SNR, when only imperfect and outdated channel state information (CSI) is available, cannot be expressed in closed form, we develop an approximate statistical model which is based on the beta distribution. Our model is compared in terms of approximation accuracy against models based on the Gaussian distribution, the gamma distribution and the more complex Pearson and generalized extreme value (GEV) distributions.

[C86] P. Del Fiorentino, C. Vitiello, V. Lottici, F. Giannetti, M. Luise, “A Robust Resource Allocation Algorithm for Packet BIC-UFMC 5G Wireless Communications,” EUSIPCO 2016, Budapest, Hungary, August 29-September 2, 2016.

In this paper, we present a novel resource allocation (RA) algorithm for packet Universal Filtered Multi-Carrier (UFMC) BIC-based communications, the latter being a novel modulation format possibly envisaged to be applied in 5G wireless systems. Assuming the perfect knowledge of the channel and capitalizing on the specific UFMC signal waveform, the proposed RA strategy optimizes the coding rate and bit loading within the overall bandwidth along with the per-subband power distribution. In the presence of a carrier offset and over fading selective channels, the results we obtained are twofold: i) the UFMC format reveals to be more robust than the conventional OFDM scheme; ii) the performance of the UFMC system itself is further boosted by the optimal choice of radio resources evaluated by the proposed RA algorithm.

[C87] C. Vitiello, P. Del Fiorentino, V. Lottici, F. Giannetti, M. Luise, E. Debels, M. Moeneclaey, “Two-Step Resource Allocation for BIC-UFMC Wireless Communications,” 13th International Symposium on Wireless Communication Systems (ISWCS’16), Poznan, Poland, September 20–23, 2016.

This paper outlines an efficient resource allocation (RA) algorithm for packet-oriented Universal Filtered Multi-Carrier (UFMC) communications with bit interleaved coded (BIC) modulation. Assuming perfect synchronization and perfect knowledge of the channel, the proposed RA strategy optimizes the coding rate, bit loading and power distribution within the subbands and the subcarriers of the BIC-UFMC system maximizing the goodput (GP) metric. The bit loading operation is implemented by means of a greedy algorithm in order to reduce the computational complexity of the overall RA. In the presence of a frequency-selective fading channel, we show an improvement of the GP around 0.5 bit/s/Hz in comparison with a uniform bit and power allocation.

[C88] S. Saponara, F. Giannetti, B. Neri, “Design Exploration for Millimeter-Wave Short-Range Industrial Wireless Communications,” 42nd Annual Industrial Electronics Conference (IECON2016), Florence, Italy, October 24-27, 2016. Best Session Presentation Award.

This work proposes models and a link design method to exploit the potentiality of millimeter waves (mmW) as physical layer of industrial networking protocols. This work shows that, even taking into account harsh operating conditions, a transmitted power of 10 dBm allows for reliable connections at a distance of tens of meters. With respect to traditional sub-3 GHz wireless connections used in indoor industrial environments, mmW links feature worldwide-unlicensed ISM (Industrial Scientific Medical) wideband. This can be exploited to implement frequency-hopping and frequency-diversity techniques to increase link robustness. Operating at mmW allows for inherent interference separation from operating frequencies of electrical machine, power switching converters and other wireless connections. Implementation results of key hardware building blocks with CMOS and PCB technologies prove the feasibility of mmW nodes with low-power and low size.

[C89] E. Debels, P. Del Fiorentino, C. Vitiello, J. Van Hecke, F. Giannetti, M. Luise, V. Lottici, M. Moeneclaey, "Adaptive modulation and coding for BIC-UFMC and BIC-OFDM systems taking CFO into account," 23rd IEEE Symposium on Communications and Vehicular Technology in the Benelux 2016 (SCVT 2016), Mons, Belgium, November 22, 2016.

The performance of multicarrier systems can be considerably degraded because of inter-carrier interference (ICI) caused by a carrier frequency offset (CFO) between the transmitter and the receiver. A recently developed multicarrier modulation technique, referred to as uniform filtered multicarrier (UFMC), improves the robustness against CFO, thereby relaxing the synchronization requirements, consequently providing energy efficient and low latency transmissions. However, the goodput (GP) of the system still rapidly drops with increasing CFO when using the classical adaptive modulation and coding (AMC) schemes based on the SNRs of the subcarriers, because they ignore the presence of the CFO-induced ICI. To tackle this problem, this contribution performs the AMC, also taking into account the ICI caused by the CFO, and thereby achieving a significant increase of the GP.

[C90] P. Del Fiorentino, C. Vitiello, V. Lottici, F. Giannetti, M. Luise, E. Debels. J. Van Hecke, M. Moeneclaey, “Resource Allocation in Short Packets BIC-UFMC Transmission for Internet of Things,” IEEE GLOBECOM 2016, International Workshop on Emerging Technologies for 5G Wireless Cellular Networks, Washington, DC, USA, December 4, 2016.

This paper presents a resource allocation (RA) strategy for bit interleaved coded UFMC (BIC-UFMC) communications to be applied in an Internet of Things scenario characterized by short packets. The proposed RA strategy selects the best transmission parameters (TPs), i.e. code rate, bit loading (BL), power allocation (PA) and number of multicarrier symbols, by maximizing the goodput (GP) metric over a frequency-selective fading channel. The results are twofold: i) the GP performance of the BIC-UFMC system is further boosted by the best choice of the TPs compared to the case of Uniform PA and BL and a previous GP-based RA solution, named Classical RA; ii) considering the frequency offset, the combination of RA and BIC-UFMC reveals to be more robust than the Uniform and Classical cases.

[C91] S. Saponara, F. Giannetti, “Radio Link Design Framework for WSN Deployment and Performance Prediction,” in the proceedings of SPIE 2017 Microtechnologies, Vol. 10246 "Smart Sensors, Actuators, and MEMS VIII," 102461J (2017), Barcelona, Spain, May 8-10, 2017, pp. 1-7.

For an easy implementation of wireless sensor and actuator networks (WSAN), the state-of-the-art is offering single-chip solutions embedding in the same device a microcontroller core with a wireless transceiver. These internet-on-chip devices support different protocols (Bluetooth, ZigBee, Bluetooth Low Energy, sub- GHz links), from about 300 MHz to 6 GHz, with max. sustained bit-rates from 250 kb/s (sub-GHz links) to 4 Mb/s (Wi-Fi), and different trade-offs between RX sensitivity (from -74 to -100 dBm), RX noise figure (few dB to 10 dB), maximum TX power (from 0 to 22 dBm), link distances, power consumption levels (from few mW to several hundreds of mW). One limit for their successful application is the missing of an easy-to-use modeling and simulation environment to plan their deployment. The need is to predict, before installing a network, at which distances the sensors can be deployed, the real achievable bit-rate, communication latency, outage probability, power consumption, battery duration. To this aim, this paper presents the H2AWKS (Harsh environment and Hardware Aware Wireless linK Simulator) simulator, which allows the planning of a WSAN taking into account environment constraints and hardware parameters. Applications of H2AWKS to real WSAN case studies prove that it is an easy to use simulation environment, which allows design exploration of the system performance of a WSAN as a function of the operating environment and of the hardware parameters of the used devices.

[C92] G. Bacci, F. Binaglia, L. Facheris, D.V. Finocchiaro, F. Giannetti , M. Moretti, A. Ortolani, A. Petrolino, R. Reggiannini, A. Vaccaro, "The NEFOCAST project: A nowcasting weather platform based on dual-frequency interactive satellite terminals," in the proceedings of the 32nd International Union of Radio Science General Assembly & Scientific Symposium (URSI GASS), Montreal, Canada, August 19–26, 2017, pp. 1-4.

In this paper, we present a research project named NEFOCAST, that targets a very-short-term forecasting platform with high accuracy and small-scale spatial resolution. The innovative solution lies in adopting a new generation of interactive satellite terminals, called SmartLNB, that serves both as a weather sensor and the transceiver for the forecasting platform. Throughout the paper, we highlight the main features of the system, including the advantages compared to state-of-the-art solutions, the expected results, and the market perspectives.

[C93] E. Adirosi, L. Facheris, A. Petrolino, F. Giannetti, R. Reggiannini, M. Moretti, S. Scarfone, S. Melani, F. Collard, G. Bacci, "Exploiting satellite Ka and Ku links for the real-time estimation of rain intensity," in the proceedings of the 32nd International Union of Radio Science General Assembly & Scientific Symposium (URSI GASS), Montreal, Canada, August 19–26, 2017, pp. 1-4.

In this paper we describe a statistical and a physically based approaches to retrieve 2D rainfall fields exploiting the attenuation measurements made along satellite links at Ka and Ku bands, in the framework of the research project NEFOCAST. The retrieval algorithms, the main results obtained so far, and the on going test campaign are presented and discussed.

[C94] M. Moretti, F. Giannetti, R. Reggiannini, L. Baldini, E. Adirosi, A. Petrolino, A. Antonini, A. Mazza, A. Colicelli, "The NEFOCAST project: Quantitative precipitation estimation based on interactive satellite terminals," in the proceedings of the 35th AIAA International Communications Satellite Systems Conference (ICSSC), Trieste, Italy, October 16-19, 2017, pp. 1-7.

In this paper we describe an algorithm to retrieve 2D rainfall fields exploiting the attenuation measurements made along satellite links. This algorithm has been developed in the framework of the project NEFOCAST, a research project funded by Tuscany region. Preliminary results show that there is a good matching between the rain rate retrieved from the satellite links’ attenuation and the rain rate measured by rain gauges and weather radar. In the future, the installation of additional devices will enable the implementation of a more sophisticated algorithm for assessing the rain rate, allowing a detailed reconstruction of the rainfall field.

[C95] S. Melo, S. Maresca, S. Pinna, F. Scotti, M. Khosravanian, Arismar Cerqueira S. Jr., F. Giannetti, A. Das Barmann, A. Bogoni, "High Precision Displacement Measurements in presence of Multiple Scatterers using a Photonics-based Dual-band Radar," in the proceedings of the International Conference on Radar Systems (Radar 2017), October 23-26, 2017, Belfast, UK, pp. 1-6.

In this work, a dual-band photonics-based radar system is described for precise displacement measures in a multi-target scenario. The radar has been designed for application of monitoring and prevention of possible structural failures of buildings and landslides. The radar system exploits the Stepped Frequency Continuous Wave (SFCW) signal modulation and differential phase measurements are carried out on each range bin to evaluate target displacements. The system effectiveness has been already demonstrated in presence of a single target. Here we present a numerical and experimental evaluation of the displacement estimation accuracy in the case of a multi-target scenario. Our study is focused to understand how the presence of multiple targets impacts on their displacement estimates. Simulation results show a typical accuracy of less than 0.2 mm for distances up to 400 m. These results are confirmed by preliminary experimental outcomes, which take into account different operative conditions in a first measure campaign with multiple targets. Finally, concluding remarks and perspectives draw the agenda for our future investigations.

[C96] F. Caparrini, S. Melani, A. Antonini, A. Mazza, A. Ortolani, F. Giannetti, M. Moretti, R. Reggiannini, A. Colicelli, L. Facheris, G. Bacci, A. Petrolino, A. Vaccaro, "Real-time high resolution rainfall maps from a network of ground-based interactive satellite terminals: the NEFOCAST project," in the proceedings of the IEEE IoT Vertical and Topical Summit on Agriculture - Tuscany (Tuscany2018), Monteriggioni (SI), Italy, May 8–9, 2018, pp. 1-2.

Rainfall estimation and its spatial distribution are key elements for agriculture. Actually, rainfall maps over cultivated areas are needed for efficient water resources management, while prediction and monitoring of severe precipitation events are required for the estimation of possible damages and risks for crops, animals and infrastructures. Spatial and temporal accuracies of rainfall estimates are crucial, especially in case of intense and localized phenomena. Conventional instruments such as rain gauges provide point estimations, but the setup of a dense network requires high installation and maintenance costs. On the other hand, techniques based on satellite remote sensing or weather radars present specific limitations either in terms of data availability, sources of error, cost, or spatial and temporal resolution. A promising alternative is the exploitation of modern telecommunication technologies that, albeit not specifically developed for rainfall estimation, can bring relevant information through the measurement of the attenuation caused by raindrops on broadcast satellite signals. NEFOCAST1 is a research project funded by Tuscany Region (Italy) which implements such an approach based upon a dense population of ground-based Interactive Satellite Terminals (ISTs). The IST employed in the project is an innovative two-way (i.e., transmit/receive) device named Smart Low-Noise Block converter (SmartLNB). Usage of smart LNBs has many advantages in terms of cost and setup and has a great potential for application worldwide including areas where hydro-meteorological networks are not fully developed. In the framework of this project, an experimental network of SmartLNBs has been installed in Tuscany Region in Central Italy and a dedicated platform (NEFOCAST Service Center) has been set up where the data is collected (via ground-to-satellite link), processed and shared with a number of value-added service providers (VASPs). Real-time estimates (with 1 minute update) of rain rates as ‘seen’ by the SmartLNBs are produced through a processing algorithm based on the relationship between the rain rate and the signal attenuation with respect to clear-sky conditions. The real-time point estimates are filtered with a space-time Kalman filter to predict the pattern and evolution of the rainfall field and produce high resolution maps. This work is focused on the simulation of a set of case studies, featuring several storms with different spatial-temporal patterns and intensities. The 3D simulated rainfall fields are used as a virtual reality for the synthetic reconstruction of a set of SmartLNBs measurements over randomly located points. The relevant rainfall maps are then produced by use of the above mentioned Kalman filter approach over the set of synthetic SmartLNBs measurements. Finally a simple linear model of the storm evolution is introduced to test the ability of such algorithm to reconstruct the dynamic of the precipitation system. The impacts of various factors such as SmartLNB density, satellite link geometry, rainfall characteristics (e.g. horizontal/vertical structure, convective/stratiform event), are investigated and the potential for practical applications is eventually discussed.

[C97] E. Adirosi, A. Antonini, G. Bacci, F. Caparrini, L. Facheris, F. Giannetti, A. Mazza, M. Moretti, A. Petrolino, R. Reggiannini, A. Vaccaro, L. Baldini. "NEFOCAST project for real-time precipitation estimation from Ku satellite links: Preliminary results of the validation field campaign," in the proceedings of the 2nd URSI Atlantic Radio Science Conference (URSI AT-RASC), May 28 - June 1, 2018, Meloneras, Gran Canaria, Spain, pp. 1-4.

NEFOCAST is a project funded by the Tuscany Region Government (Italy) that aims at setting up, and demonstrating through field experiments, the concept of a system able to provide precipitation maps in real-time based on the attenuation measurements collected by a dense population of interactive satellite terminals (called SmartLNB, smart Low-Noise Block converter) commercially used as bidirectional modems. The system does not require the set-up of specific precipitation measuring instruments, but uses telecommunication links. An algorithm that converts the SmartLNB raw data into attenuation values, and infers rainfall rate from the total signal attenuation provided by the devices and from the knowledge of the link geometry, has been developed. An experimental campaign will take place in 2018 in Tuscany with the purpose of validating the NEFOCAST estimates, obtained through a dense population of smartLNBs and an X-band dual-polarization weather radar, purposely installed. During a preliminary test phase, performance of the algorithm has been assessed tested by comparing data from individual smartLNBs with tipping bucket rain gauge and a co-located laser disdrometer. This study presents and discusses results obtained during the test phase, focusing on disdrometer evaluation.

[C98] F. Giannetti, M. Moretti, R. Reggiannini, A. Petrolino, G. Bacci, E. Adirosi, L. Baldini, L. Facheris, S. Melani, A. Ortolani, "The Potential of SmartLNB Networks for Rainfall Estimation," in the proceedings of the 2018 IEEE Statistical Signal Processing Workshop (SSP), Freiburg, Germany, June 10-13, 2018, pp. 120-124.

NEFOCAST is a research project that aims at retrieving rainfall fields from channel attenuation measurements on satellite links. Rainfall estimation algorithms rely on the deviation of the measured E_s /N_0 from the clear-sky conditions. Unfortunately, clear-sky measurements exhibit signal fluctuations (due to a variety of causes) which could generate false rain detections and reduce estimation accuracy. In this paper we first review the main causes of random amplitude fluctuations in the received E_s /N_0 , and then we present an adaptive tracking algorithm based on two Kalman filters: one that tracks slow changes in E_s /N_0 due to external causes and another which tracks fast E_s /N_0 variations due to rain. A comparison of the outputs of the two filters confirms the reliability of the rainfall rate estimate.

[C99] S. Melani, A. Antonini, A. Ortolani, L. Baldini, E. Adirosi, L. Facheris, F. Giannetti, A. Petrolino, “Studies of the Melting Layer of Precipitative Systems Using X-Band Dual Polarization Weather Radar and SmartLNB Network,” in the proceedings of the 10th European Conference on Radar in Meteorology and Hydrology (ERAD 2018), Ede-Wageningen, The Netherlands, July 1–6, 2018, pp. 274-275 (poster presentation).

The characterization of the melting layer (ML) is an important task for operational radar meteorology. Melting layer identi?cation may be used to establish distances at which radar rainfall estimates become affected by melting hydrometeors, with bene?ts for operational hydrometeor classi?cation, as snowfall, freezing rain and liquid precipitation. Consequently, this yields a significant performance improvement in radar-based quantitative precipitation estimation (QPE) on ground. Furthermore, knowledge of the ML location is also important for microphysical cloud characterization and the evaluation of icing potential. Several studies and algorithms exist in literature for characterizing ML through radar measurement signature, the most popular being the increase in the radar reflectivity factor known as bright. For dual polarization radar, ML detection can be pursued using specific signatures of dual polarization measurements, such as differential reflectivity ZDR, co-polar correlation coefficient ?HV, specific differential phase KDP, and linear depolarization ratio LDR that exhibit well-pronounced ML signatures both in stratiform and even in convective situations. Moreover, ML and rainfall have a strong influence on satellite links signals, as they are attenuated due to the presence of hydrometeors along the propagation path. In stratiform precipitation systems, the ML is the upper limit of the rainfall column height that is responsible of the attenuation of radio signals. Therefore, ML climatology is proficiently used for designing satellites links relative to a specific area. Very recently, a new X-band Doppler, dual-polarization weather radar system has been installed in Florence funded by the Tuscany Region Government within the NEFOCAST project. The latter investigates a new concept system that aims at providing real time precipitation maps trough the attenuation measurements collected by a dense population of new-generation interactive satellite terminals (called SmartLNB, Smart Low-Noise Block converter). A number of SmartLNB has been deployed in the Tuscany region and a test bed has been established in cooperation with the schools of the Florence Metropolitan city. In the present study, the potential of the new weather radar system is investigated for characterizing the ML in terms of height and thickness under different meteorological conditions and cloud systems. Measurements collected in the Range–Height Indicator (RHI) scan mode along the direction to the Eutelsat 10A satellite (used for the experimental campaign of the NEFOCAST project) have been analysed with the simultaneous attenuation estimation obtained by the SmartLNBs with radar coverage during selected precipitative events. Statistical analyses have been performed based on both weather radar and SmartLNB measurements, supplemented by ancillary observations from some raingauges (both impact and tipping-bucket types) co-located with SmartLNBs. In addition, a C-band radar system (Polar 55C) located in Rome has also been used for this work. Polar 55C dual polarization measurements have been analysed with respect to co-located SmartLNBs and laser disdrometer. The results of this analysis highlight the effects of ML on radio signal attenuation, as the total attenuation of signal increases also with the increase of ML vertical thickness. Therefore, the characterization of the vertical profile of precipitation is mandatory for implementing accurate QPE on ground, both from radars and satellite links.

[C100] F. Giannetti, R. Reggiannini, M. Moretti, S. Scarfone, A. Colicelli, E. Adirosi, F. Caparrini, A. Mazza, G. Bacci, A. Petrolino, A. Vaccaro, L. Facheris, "Kalman Tracking of GEO Satellite Signal for Opportunistic Rain Rate Estimation," in the proceedings of the 2018 15th International Symposium on Wireless Communication Systems (ISWCS), Lisbon, Portugal, August 28-31, 2018, pp. 1-5.

In the NEFOCAST project we aim at estimating rainfall by the opportunistic use of the signal attenuation due to the propagation channel in satellite communications. The estimation is performed by reverse engineering the effects of the various propagation phenomena on the satellite signal. However, the accuracy of the estimation is affected by several factors: in first place the rapid fluctuations in signal amplitude caused by small-scale irregularities in the tropospheric refractive index; secondly, the perturbations of the orbit of GEO satellites, such as the gravitational effects of the moon and the sun, which, even if periodically counteracted by correction maneuvers, nevertheless cause residual orbit inclinations. The problem with all these factors is that they can cause large deviations in the clear-sky measurements that can be misinterpreted as rain events. In this paper we address these problems by employing two Kalman filters designed to track slow and fast changes of the received signal energy, so that the rain events can be reliably estimated.

[C101] A. Ortolani, S. Melani, A. Antonini, A. Mazza, F. Caparrini, S. Scarfone, F. Giannetti, L. Facheris, Luca Baldini, A. Vaccaro, A. Petrolino, "Real-time rainfall maps based on satellite broadcast signal attenuation," in the proceedings of the 1^ Congresso Nazionale della Associazione Italiana Scienze dell'Atmosfera e Meteorologia (CN1-AISAM), Bologna, Italy, September 10–13, 2018, pp. 157-159 (poster presentation).

In spite of the variety of existing methods to measure precipitation, the retrieval of rainfall fields is still a matter of research, because of the high number of applications in different fields critically dependent on rainfall data and thus demanding for upgraded precisions in quantity estimation, spatial distribution and resolution, as well as for homogeneous retrieval over large domains. Telecommunication technologies can bring relevant information on rainfall rate, through the measurement of the attenuation caused by raindrops on broadcast satellite signals, albeit not specifically developed for this. NEFOCAST is a FAR-FAS research project funded by Regione Toscana, which exploits this feature through innovative two-way (i.e., transmit/receive) devices named Smart Low-Noise Block converter (SmartLNB), that are going to constitute a free-of-charge network of sensors, densely distributed in urbanised areas. Usage of smart LNBs has many advantages in terms of cost and setup and has a great potential for application worldwide including areas lacking of meteorological data, providing also an efficient data transmission solution. In NEFOCAST an experimental network of SmartLNBs has been deployed in Florence and analysed through a co-located rain gauge network and a Doppler polarimetric X-band radar for cal/val objectives. The high rate of attenuation measurements provided by the SmartLNBs (in our case 1 min.), suggests to approach the rainfall retrieval problem similarly to a trajectory assessment in a phase space, using a Kalman filter to achieve the rainfall field over a target domain. SmartLNBs provide an average measurement along a non-nadir path, so that information on the structure of the intercepted rainfall system are needed to retrieve ground precipitation, and MSG satellite observations can be used at the purpose. In this work we will present the measurement concept, the signal processing algorithm, and the method to estimate the rainfall fields. Firstly, some significant synthetic case studies will be introduced, featuring some events with different precipitation patterns; then, real SmartLNB measurements, acquired during different meteorological conditions, will be discussed, analysing also the impacts of SmartLNB density, satellite link geometry and structure of rainfall systems.

[C102] E. Adirosi,, L. Baldini, L. Facheris, F. Giannetti, A. Antonini, S. Melani, A. Vaccaro, A. Petrolino, “Validation of rainfall estimation derived from commercial DVB received signal with disdrometer, rain gauges and ground based radar,” in the proceedings of the 3rd Italian Workshop on Radar and Remote Sensing, Rome, Italy, May 30–31, 2019, pp. 1 (poster presentation).

An accurate measurement and monitoring of precipitation events is closely linked with different applications that have an impact on human welfare such as water resources management, and floods, landslides or wildfire risk assessments. Currently rain gauges, disdrometers, ground-based weather radars and satellite sensors (both active and passive) can be considered the conventional devices for precipitation measurements that are worldwide adopted. These devices have different measurement principles, time and space resolution, and accuracy (Gebremichael and Testik, 2013). In the last decade, a new technology that exploits the microwave satellite links has been investigated to retrieve precipitation information. The idea is to estimate the precipitation starting from the attenuation of the signal along its propagation path. Few studies have been carried out in this direction (such as Barthès and Mallet, 2013 and Mercier et al., 2015), showing promising results. In that regards, recently, an Italian project called NEFOCAST, funded by Tuscany Region (Italy), has been carried out with the aim of estimating rainfall rate from attenuation measurements made available by commercial interactive digital video broadcasting (DVB) receivers, called smartLNBs. During the NEFOCAST project, an ad hoc rainfall retrieval algorithm has been developed, tuned and tested. It allows to estimate, with 1-minute rate, the instantaneous rainfall rate (R, in mm/h) from the ratio \eta = E_s/N_0 between the received energy-per-symbol E_s and the one-sided power spectral density of the additive white Gaussian noise N_0, (Giannetti et al. 2017). To validate the algorithm, a 1-year field campaign (from January 2018 to January 2019) was conducted. The collected data allow to compare the SmartLNB precipitation estimates with the measurements gathered by ‘conventional’ meteorological devices such as rain gauges, weather radar and disdrometer. A network of 24 smartLNBs was deployed in Tuscany, along with 11 rain gauges and one X-band dual-polarization weather radar. Furthermore, the performance of the NEFOCAST algorithm has been preliminarily tested by comparing data provided from one SmartLNB installed at the Institute of Atmospheric Sciences and Climate (ISAC) of CNR in Rome (Italy) with a co-located laser disdrometer. For this site, data from a dual polarization C-band weather radar (Polar55C) could be compared with SmartLNB measurements along the Earth-satellite link. In fact, during the project the Polar55C has been aimed in the same direction as the SmartLNB, with the same elevation angle, thus scanning the same portion of atmosphere where the SmartLNB signal was propagating. Preliminary results show a good agreement between the total cumulative precipitation (in mm) obtained from SmartLNB data and the one collected by the co-located disdrometer during different rainfall events. The corresponding values of Normalized Mean Absolute Error (NMAE) and Root Mean Square Error (RMSE) obtained comparing the total cumulative precipitations obtained from SmartLNB and disdrometer are 41% and 4.71 mm, respectively. Encouraging results come also from the comparison of the total precipitation amounts as measured by the network of SmartLNBs and rain gauges, with values of NMAE (RMSE) that range between 39% and 53% (2.8 mm and 8.0 mm), depending on the specific site.

[C103] A. Ortolani, S. Melani, A. Antonini, A. Mazza, F. Caparrini, F. Giannetti, L. Facheris, L. Baldini, A. Vaccaro, “Real-time precipitation maps from satellite broadcast signals,” in the proceedings of the 12th International Precipitation Conference (IPC12), Irvine, USA, June 19 - 21, 2019, pp. 140 (poster presentation).

Broadcast satellite telecommunication bring information on rainfall rates along their path, through the signal attenuation, caused by raindrops. We exploited this feature with new two-way (transmit-receive) devices named SmartLNB (Smart Low-Noise Block converter), that are going to constitute networks of sensors of opportunity, in any urbanised areas. Albeit not specifically developed for meteorology, two-way receivers centralise attenuation data, ready to be processed for rainfall estimation, every minute. The high rate of real-time measurements provided by SmartLNBs suggested approaching the rainfall retrieval problem as a trajectory assessment in a phase space, using an ensemble Kalman filter, to produce rainfall fields over a given spatial domain. SmartLNBs provide average measurements along quasi-parallel non-nadir satellite-receiver paths, so that information on the structure of the intercepted rainfall system have to be known to retrieve ground precipitation. MSG satellite observations can be used at the purpose and as initial and boundary conditions, while atmospheric motion vectors from the same data source are used in the propagation model of the Kalman filter. A cross-shaped experimental network of a dozen SmartLNBs has been deployed in Florence (Italy) with co-located raingauges and one doppler polarimetric X-band radar for cal/val objectives. In this work, we present the measurement concept, the signal processing algorithm, the method to estimate the rainfall fields and the results, notable over the expectations. Firstly, some significant synthetic case studies are illustrated, for various precipitative events with different intensity, dynamics and morphology and for various sensor distributions. Then real measurement retrievals (single and collective) from the project network are shown and results discussed, with attention to the sensitivity of the technique to receiver density, satellite link geometry and rainfall systems characteristics.

[C104] F. Saggese, F. Giannetti, V. Lottici, "3-D Rain Rate Estimation from Integrated Measurements of Commercial Wireless and Satellite Links: an Overview," Symposium on the hydrometeorological usage of data from commercial microwave link networks, Contribution ID: 29, KIT Campus Alpin, Garmish Partenkirken, Germany, June 25-28, 2019, pp. 1-2.

In the last decade, various algorithms have been developed to provide accurate rainfall maps from measurements of rain-induced attenuation on commercial wireless links (CWLs). These solutions are able to give precise results but they also require dense terrestrial microwave networks, which have non negligible installation and operating costs. A cheaper alternative for rainfall estimation is represented by broadcast satellites links (BSLs). However, estimation of the rain-induced attenuation on satellite links requires complex signal processing techniques, due to the physical structure of these links. Furthermore, to the best of authors’ knowledge, data provided by satellite links only cannot be used to properly estimate a precise rainfall map of an area. To overcome these problems, we studied a mixed approach based on data given by both CML and BSL, able to provide a three-dimensional (3-D) rain rate map of a monitored area. The proposed joint approach gives us remarkable appealing advantages: 1. Efficiency: both CWLs and BSLs exploit already existing wireless infrastructure, at no extra costs for the required equipments, the installation and operating conditions. 2. Coverage: CWL coverage can be improved by including satellite terminals already installed at domestic premises for TV reception. Additionally, more satellite devices can be purposely installed in areas not adequately covered by terrestrial microwave links, where the deployment of conventional methods of observation, as rain gauges and weather radars, is impractical. 3. Diversity: measuring the signal levels coming from different links, terrestrial and satellite, provides a diversity gain which is the key to improve the accuracy and reliability of the overall joint system. 4. Accuracy: the numerical results obtained by simulations corroborate the effectiveness of the proposed mixed 3-D strategy and quantify the improvements over the conventional systems based on CWLs only. Our contribution lies in the description of the data processing schemes developed to retrieve these maps. In particular, the first part consist in pointing out the problems connected to the satellites links and a signal processing approach able to provide precise data of estimated rainfall. Then, a summary of the algorithm will given and preliminary results obtained by the proposed approach will be presented, in order to show the effectiveness of our approach.

[C105] F. Saggese, F. Giannetti, V. Lottici, "3-D Rain Rate Estimation from Integrated Measurements of Commercial Wireless and Satellite Links," Symposium on the hydrometeorological usage of data from commercial microwave link networks, Contribution ID: 46, KIT Campus Alpin, Garmish Partenkirken, Germany, June 25-28, 2019, pp. 1-2.

In the last decade, various algorithms have been developed to provide accurate rainfall maps from measurements of rain-induced attenuation on commercial wireless links (CWLs), such as [1]. These solutions provide precise results but they also require dense terrestrial microwave networks, which have non negligible installation and operating costs. A cheaper alternative for rainfall estimation is represented by broadcast satellites links (BSLs). However, to the best of authors’ knowledge, these approaches are able to estimate the rainfall rate on a single point only [2]-[4]. To gain all the benefits provided by both the cited schemes, we propose an adaptation of the state-of-the-art algorithm in [1] which is able to integrate the data provided by both the CWLs and BSLs, yielding a threedimensional (3-D) rain rate map of a monitored area. Our contribution lies in the technical description of the data processing schemes developed to retrieve these maps, with particular interest in the 3-D system model. In the following, we summary the machinery of our approach. Let us consider a monitored zone, where N = Nw + Ns communication links are active, with Nw and Ns are the number of CWLs and BSLs, respectively. It is worth noting that rain is assumed only present below the 0 degree isotherm height. We divide then the vertical dimension into H fixed heights, from ground level up to the 0 degree isotherm height. Hence, by implementing the algorithm in [1] for each height, we obtain a set of H rain maps, one for each height value, yielding to a 3-D description of the phenomena. The effectiveness of novel approach is assessed using a simulator able to set up a configuration of the coordinates for both CWL and BSL terminals, and an instance of a simulated rain in a randomly-generated position. Preliminary results are given in Figures 1 and 2 (presented into the attached file) which illustrate different scenarios in the presence of the same rain conditions. In the scenario of Fig. 1, the estimation is performed using only 21 CWLs, while Fig. 2 presents the estimation results using 13 BSLs and 8 CWLs. Though the position of the rain column with diameter 3 km is correctly estimated in both cases, it can be nevertheless noted that the joint utilization of both CWL and BSL provides a more accurate estimation of the rain intensity. To show a more general prove of effectiveness, the near-to-the-ground RMSE between actual and estimated rain rate is plotted for different scenarios. In Fig. 3, the RMSE is shown as a function of the number of wireless links, randomly chosen from the arrangement presented in Fig. 1. The curves are plotted for different numbers of satellite receivers, i.e., 0, 4, 8 and 16 randomly-positioned on the maps. It is apparent that even a few number of satellites can be of great help in reducing the RMSE.

[C106] L. Baldini, E. Adirosi, A. Antonini, S. Melani, F. Caparrini, A Mazza, A. Ortolani, L. Facheris, F. Giannetti, A. Vaccaro, "Validazione di una innovativa rete di rilevamento pluviometrica basata sulla misura opportunistica di segnali televisivi diffusi da satellite," (in Italian) in the proceedings of the Convegno Nazionale di Radarmeteorologia (Radmet2019.IT), Turin, Italy, July 3-4, 2019. pp. 1-2.

Nonostante la varieta' di metodi e strumenti esistenti per la misura di precipitazioni, non esiste un metodo che funzioni meglio di tutti gli altri in tutte le condizioni operative. I pluviometri sono gli strumenti tradizionalmente utilizzati per ottenere misure puntuali con elevata precisione del quantitativo d’acqua che precipita in un determinato intervallo di tempo. I sistemi radar meteorologici consentono invece di stimare la distribuzione spaziale della precipitazione e di monitorarne la dinamica, pur se con precisioni minori. Infine i satelliti consentono in maniera indiretta di stimare la precipitazione su scale molto più ampie, ma al prezzo di un aumento dell’incertezza e di una minor risoluzione spazio temporale. Rispetto a questi strumenti tradizionali ve ne sono alcuni che derivano da un uso opportunistico di sistemi progettati e realizzati per altri scopi, ma che possono comunque fornire informazioni utili alla stima della precipitazione. In particolare, i sistemi di telecomunicazione che impiegano radiocollegamenti con frequenze superiori al GHz possono fornire informazioni rilevanti sulle precipitazioni, attraverso la misurazione dell'attenuazione del segnale trasmesso causata dalle gocce di pioggia nella tratta dal trasmettitore al ricevitore. NEFOCAST e' un progetto di ricerca FAR-FAS finanziato dalla Regione Toscana, che sfrutta questa opportunita' attraverso innovativi dispositivi satellitari bidirezionali (cioè trasmettitori/ricevitori) denominati Smart Low-Noise Block converter (SmartLNB), concepiti per l’interazione ubiquitaria via satellite ma in grado di rilevare il valore di attenuazione del segnale ricevuto e di trasmetterlo direttamente ad un centro di raccolta. L'utilizzo di SmartLNB presenta significativi vantaggi in termini di costi e facilita' di installazione/configurazione e fornisce la possibilità di applicazione in qualsiasi area coperta dal segnale satellitare, offrendo al tempo stesso un'efficiente soluzione “embedded” per la trasmissione dei dati, senza necessita' di ricorrere a ricevitori dedicati per la stima della pioggia. L’algoritmo di stima della precipitazione di NEFOCAST e' stato studiato basandosi su modelli fisici e su modelli empirico-statistici. Per tale scopo sono state effettuate delle campagne di misura utilizzando uno SmartLNB, un radar meteorologico (puntato nella stessa direzione del satellite) ed un disdrometro co-locati presso la sede del CNR-ISAC di Roma. L’algoritmo di stima dei campi di precipitazione e' stato implementato attraverso un filtro di Kalman che utilizza come dati di input le misure degli SmartLNB e dati ausiliari da osservazioni satellitari. Durante il progetto NEFOCAST e' stata infine condotta una campagna di test e validazione dell’algoritmo messo a punto per la stima della precipitazione a partire da misure di attenuazione effettuate con gli SmartLNB. Durante tale campagna di misura, della durata di un anno circa, sono stati dislocati sul territorio della Regione Toscana un numero significativo di SmartLNB. Le stime di precipitazione ottenute dalla rete di SmartLNB, opportunamente densa di terminali nell’area di Firenze, sono state analizzate attraverso i confronti con una rete di pluviometri co-locata e un radar polarimetrico X-band Doppler installato per gli obiettivi di calibrazione/validazione.

[C107] E. Adirosi, L. Baldini, L. Facheris, F. Giannetti, A. Antonini, S. Melani, A. Ortolani, A. Vaccaro, A. Petrolino, “Rainfall estimation from commercial DVB-S2 receivers for interactive broadcast applications,” in the proceedings of the 39th AMS International Conference on Radar Meteorology, Nara, Japan, September 16-20, 2019, pp. 1-2.

Accurate measurement and monitoring of precipitation events is closely linked with different applications that have an impact on human welfare such as water resources management, and floods, landslides or wildfire risk assessments. The conventional devices for the measurement or estimation of precipitation currently adopted worldwide are rain gauges, disdrometers, ground-based weather radars and satellite sensors (both active and passive) and each of them has a different measurement principle, time and space resolution, and accuracy. In the last decades, the opportunistic use of microwave telecommunication signals for meteorological applications received a growing interest. Maybe the most popular example of these unconventional approaches is the use of radio links connecting base stations of cellular networks to obtain an attenuation-based rainfall estimation. In this paper, a new technology that exploits the microwave satellite links for direct-to-home TV broadcast has been investigated to retrieve precipitation information. The idea is to estimate the precipitation starting from the attenuation of the signal along the propagation path from satellite to a user's receiver. Few studies have been carried out in this direction (such as Barthès and Mallet 2013, Mercier et al. 2015, Arslan et al., 2018) and show promising results. The regional administration of Tuscany (Italy) funded the NEFOCAST project with the aim of estimating rainfall rate from attenuation measurements made available by commercial-grade interactive receivers for digital video broadcasting via satellite (DVB-S2), called SmartLNBs. During the NEFOCAST project, an ad hoc rainfall retrieval algorithm has been developed, tuned and tested (Giannetti et al. 2017). To validate the rain retrieval algorithm, a 1-year field campaign (from January 2018 to January 2019) was conducted to compare the SmartLNB precipitation estimates with the measurements gathered by ‘conventional’ meteorological devices such as rain gauges, weather radar and disdrometer. A network of 24 smartLNBs was deployed in the Greater Florence area (Tuscany, Italy) along with 11 rain gauges and one X-band dual-polarization weather radar. Furthermore, the performance of the NEFOCAST algorithm was preliminarily tested by comparing data provided from one SmartLNB installed at the Institute of Atmospheric Sciences and Climate (ISAC) of CNR in Rome (Italy) with a co-located laser disdrometer. At this site, data from the dual polarization C-band weather radar Polar55C could be compared with SmartLNB measurements along the Earth-satellite link that was operated to collect data in the same direction as the SmartLNB, thus scanning the same portion of atmosphere where the SmartLNB signal was propagating. The results show a good agreement between the total cumulative precipitation (in mm) obtained from SmartLNB data and the one collected by the co-located disdrometer during different rainfall events. The corresponding values of Normalized Mean Absolute Error (NMAE) and Root Mean Square Error (RMSE) obtained comparing the total cumulative precipitations measured by the SmartLNB and the disdrometer are 41% and 4.71 mm, respectively. Encouraging results come also from the comparison of the total precipitation amounts as measured by the SmartLNB and by the rain gauges, with values of NMAE (RMSE) that range between 39% and 53% (2.8 mm and 8.0 mm), depending on the site.

[C108] F. Giannetti, "Radici marconiane per una realta' di eccellenza nella ricerca e nella formazione nel settore ICT," (in Italian) in the proceedings of the XV Forum Italradio, Coltano (Pisa), Italy, December 12, 2018, in F. Giannetti, L. Cobisi, P. Morandotti eds., "Da Marconi al 5G. Prospettive per le Comunicazioni Globali," printed by Nardini Editore, Florence, Italy, November 2019, pp. 9-14, ISBN-10: 8840473769, ISBN-13: 9788840473765.

Al termine delle prove sperimentali condotte con successo nel golfo della Spezia tra il 10 ed il 19 luglio 1897 con la collaborazione ed il supporto logistico della Regia Marina (RM), Guglielmo Marconi (Bologna 1874 – Roma 1937) lascio' i suoi apparati al laboratorio dell’Arsenale, dando istruzioni sul loro utilizzo e su come migliorarne le prestazioni. Grazie a ciò, la RM, che continuo' a mantenere stretti rapporti di collaborazione scientifica con Marconi, pote' iniziare anche una propria autonoma ed intensa attività di ricerca nel campo delle radiocomunicazioni a grande distanza. E fu così che nel giugno 1899 venne attrezzata una stazione radio presso l’Accademia Navale (AN) di Livorno allo scopo di avvicinare gli allievi ufficiali alla nuova disciplina, che per l’epoca rappresentava la frontiera più avanzata della tecnologia. L’AN si candidava così a diventare il più importante centro nazionale di formazione e di sperimentazione nel campo delle radiocomunicazioni.

[C109] F. Giannetti, "Marconi e l’innovativo parco antenne di Coltano," (in Italian) in the proceedings of the XV Forum Italradio, Coltano (Pisa), Italy, December 12, 2018, in F. Giannetti, L. Cobisi, P. Morandotti eds., "Da Marconi al 5G. Prospettive per le Comunicazioni Globali," printed by Nardini Editore, Florence, Italy, November 2019, pp. 35-40, ISBN-10: 8840473769, ISBN-13: 9788840473765.

Tra la fine del 1902 e l’inizio del 1903, Guglielmo Marconi manifesto' la sua intenzione di costruire una potente stazione radiotelegrafica intercontinentale in Italia ed avvio' per questo scopo dei contatti con le autorita' italiane. L’intento originario di Marconi, illustrato anche al re Vittorio Emanuele III, era quello di costruire una stazione radio “ultra potente” (cioe' concepita per servizi intercontinentali), in grado di collegare l’Italia con il Sud America. Tuttavia, questo ambizioso obiettivo venne presto abbandonato, probabilmente a causa della difficolta' tecnica di una trasmissione wireless su una così grande distanza e la stazione venne quindi proposta per fornire collegamenti radio con l’America del Nord e le colonie italiane nell’Africa Orientale. Per apprezzare quanto fosse innovativo questo progetto di Marconi, basti ricordare che nel 1903, esistevano nel Mondo solo tre stazioni ultra potenti: una in Gran Bretagna, una negli Stati Uniti ed una in Canada.

[C110] A. Ortolani, F. Caparrini, S. Melani, A. Antonini, A. Mazza, L. Baldini, F. Giannetti, L. Facheris, A. Vaccaro, “Real-time rainfall maps from satellite telecommunication signals,” in the proceedings of EGU 2020 GA - 2020 European Geoscience Union General Assembly, Online, March 4-8, 2020, pag. 1.

Modern ways to measure rainfall provide a variety of different solutions, direct and indirect, with respect to the standard approach that is the raingauge method. Retrieving the actual rain fallen on a target domain is not in fact as easy task due to its temporal and spatial variability, but its importance is paramount for meteorology and for the effects on human lives and the environment. Rainfall regimes are changing almost at every latitude with dramatic effects, with a complex connection to climate change in large part to be still understood.

[C111] F. Giannetti, M. Moretti, R. Reggiannini, A. Vaccaro, S. Scarfone, A. Ortolani, “On the Opportunistic Use of Commercial Ku and Ka Band Satcom Networks for Rain Rate Estimation: Potentials and Critical Issues,” in the proceedings of ICASSP 2020 - 2020 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), Barcelona, Spain, Online, May 4-8, 2020, pp. 9011-9015.

In this paper we study the opportunistic use of microwave satellite signals in the Ku and Ka bands to detect the presence of rain events and to estimate their intensity. This approach, based on measuring the excess signal attenuation due to rain, has the advantage that the potential number of sensors over the territory could be increased dramatically also allowing prospectively the realization of accurate regional rain maps. Moreover, employing the same satellite network whose signals are opportunistically used, the measurements can be easily fed back and universally distributed, contributing to the effective implementation of a nowcasting platform, which could help the timely detection of catastrophic rain events. Results are very promising and show that the already good estimates obtained by using signals in the Ku band can be further improved by using signals in the Ka band. Unfortunately, as of today, the frequency with which the receivers on the Ka band provide signal measurements is too low for fast changing rain events and how to address this problem is the object of future research.

[C112] V. Lottici, F. Giannetti, “Efficient Distributed Joint Path Selection and Resource Allocation in Non-Cooperative Wireless Relay Networks,” in the proceedings of URSI GASS 2020 - 2020 XXXIIIrd General Assembly and Scientific Symposium of the International Union of Radio Science, Rome, Italy, online, August 29 to September 5, 2020, pp. 1-4.

This paper proposes a distributed approach based on the network formation game (NFG) framework to joint path selection and resource allocation for a noncooperative multi-hop coded multicarrier relay network under outdated and imperfect channel state information. Simulation results corroborate the effectiveness of the proposed strategies, which offer goodput performance very close to the benchmark centralized case even with a considerable reduction in signalling and computational complexity.

[C113] F. Saggese, F. Giannetti, V. Lottici, “Novel Approach to Rainfall Rate Estimation based on Fusing Measurements from Terrestrial Microwave and Satellite Links,” in the proceedings of URSI GASS 2020 - 2020 XXXIIIrd General Assembly and Scientific Symposium of the International Union of Radio Science, Rome, Italy, online, August 29 to September 5, 2020, pp. 1-4.

Reliable, cheap and accurate measurements of rainfall rate are growing to be more and more important in many sectors as: meteorology, agriculture, flood warning, and weather forecasting. Recently, indeed, the development of novel competitive techniques has been pushed in order to improve accuracy and reliability performance, such as commercial microwave links and broadcast satellite links. The aim of the current paper is to extend previous works of the literature based on land wireless links only. The basic idea consists in synergically employing both land and satellite based approaches together, by collecting and properly fusing the corresponding measurements. To this end, an iterative optimization procedure has been developed. As shown by numerical results, the proposed procedure gives the estimated rainfall map with a considerable accuracy and improved performance respect to the conventional algorithm based on terrestrial link only.

[C114] E. Adirosi, L. Facheris, A. Antonini, F. Caparrini, F. Giannetti, A. Vaccaro, L. Baldini, “Exploiting the synergy between weather radar measurements and digital broadcasting satellite receivers to improve radar retrievals,” in the proceedings of ERAD 2020 - 11th European Conference on Radar in Meteorology and Hydrology, Locarno, Switzerland, Online, 31st Aug. - 4th Sep. 2020, pag. 1.

Nowadays, both operational and research C-band and X-band weather radars are widely used worldwide to estimate precipitation with a high temporal and spatial resolution. However, at those frequencies, both the horizontal and differential reflectivity can be altered by the effect of attenuation of waves propagating through precipitation. The latter effect can be particularly severe in case of intense precipitation and is more pronounced for X-band that for C-band. In the practice, ad hoc correction algorithms, such as those based on a relation between specific attenuation and differential phase shift, are adopted to compensate for attenuation effects. However, the verification of the accuracy of the latter algorithm is a challenging task basically due to the absence of a set of data that can be used as the reference. In this paper, we present the results of a preliminary analysis that, exploiting the synergy of weather radar and digital broadcasting satellite receivers data, aims to check and validate, and possibly tune, the attenuation correction algorithms adopted for C- and X-band weather radars.

[C115] F. Saggese, F. Giannetti, V. Lottici, “Novel Approach to Rainfall Rate Estimation based on Fusing Measurements from Terrestrial Microwave and Satellite Links,” oral communication, CML Community (virtual) meeting, Online, October 14th, 2020.

TECHNICAL REPORTS

[R1] F. Giannetti, M. Luise, R. Reggiannini, "Recupero del Sincronismo di Codice in un Modem Numerico per Sistemi CDMA/CPM", (in Italian) published by Edizioni ETS, Pisa, Italy, January 1992.

In questo rapporto viene studiato il funzionamento del circuito per il recupero del sincronismo di codice in sistemi CDMA asincroni impieganti formati di modulazione di tipo CPM. Il circuito in esame, un anello digitale detto DDLL, viene completamente analizzato per via teorica e le sue prestazioni verificate tramite simulazioni al calcolatore. Alcune modifiche alla struttura base del DDLL vengono ugualmente studiate ed analizzate.

[R2] F. Giannetti, M. Luise, R. Reggiannini, "Acquisizione del Sincronismo di Codice in un Modem Numerico per Sistemi CDMA/CPM", (in Italian) published by Edizioni ETS, Pisa, Italy, February 1992.

In questo rapporto viene studiato il funzionamento del circuito per l'acquisizione del sincronismo di codice in sistemi CDMA asincroni impieganti formati di modulazione di tipo CPM. Il circuito in esame viene completamente analizzato per via teorica e le sue prestazioni verificate tramite simulazioni al calcolatore.

[R3] F. Giannetti, "Simulazione Tramite Calcolatore di Sistemi in Ponte Radio Operanti in Condizioni di Background B.E.R.", (in Italian) published by Edizioni ETS, Pisa, Italy, February 1992.

In questo lavoro vengono presentati alcuni modelli che descrivono il comportamento di un sistema di trasmissione numerico basato su ponte radio ed operante in condizioni di background BER. Viene inoltre preso in considerazione l'utilizzo di tecniche di codifica per correzione di errore (FEC). I modelli di canale descritti sono implementati in software mediante programmi FORTRAN impieganti il pacchetto SPACE, sviluppato presso il Dipartimeno di Ingegneria dell'Informazione dell'Universita' degli Studi di Pisa. I programmi, di cui viene riportata una descrizione dettagliata, forniscono in uscita i dati relativi alle statistiche di eventi errore verificatisi sul canale con o senza FEC, consentendo cosi' di effettuare delle valutazioni sulle prestazioni complessive del sistema di comunicazione.

[R4] R. De Gaudenzi, F. Giannetti, "Analysis of an Advanced Satellite Digital Audio Broadcasting System and Complementary Terrestrial Gap-Filler Single Frequency Network", ESA/ESTEC EWP 1690, European Space Research and Technology Centre (ESA/ESTEC), Noordwijk, The Netherlands, November 1992.

Digital Audio Broadcasting (DAB) to mobile and fixed users exploiting the latest advances in compression, coding and transmission techniques represents an appealing application for future satellite systems. This paper introduces Coded Quasi-Orthogonal Code Division Multiplexing (CQO-CDM) as transmission technique for digital audio broadcasting. The proposed technique performs well over both the L-band satellite fading channel and the terrestrial gap-filler type of transmission. Preliminary link budgets based on extensive computer simulation results are also provided. Numerical results show that a remarkable overall capacity can be achieved by using a constellation of satellites in Highly Elliptical Orbit (HEO) complemented by terrestrial gap-filler network. A variety of transmission rates, and hence broadcasting services, can be realized with the proposed transmission technique. It is shown that a Geostationary Orbit (GEO) satellite can provide limited service availability to mobile user, but it can also be used for experimental purposes.

[R5] R. De Gaudenzi, F. Giannetti, "Analysis and Performance Evaluation of Synchronous Trellis-Coded CDMA for Satellite Applications", ESA/ESTEC EWP 1691, European Space Research and Technology Centre (ESA/ESTEC), Noordwijk, The Netherlands, November 1992.

In this paper synchronous trellis-coded code-division multiple-access (S-TC-CDMA) is introduced and analyzed. Compared with asynchronous CDMA (A-CDMA) and uncoded synchronous CDMA (S-CDMA) systems, S-TC-CDMA improves the power and/or the bandwidth efficiency by using trellis-coded PSK or QAM modulation in conjunction with independent quasi-orthogonal I-Q direct-sequence spectrum spreading (DS/SS). An approximate formula for the bit error rate performances of S-TC-CDMA in the AWGN channel with co-channel interference has been derived and favorably compares to computer simulation results. Fianlly, we investigate the impairements due to satellite nonlinearities and multipath fading and the system performance is reported.

[R6] R. De Gaudenzi, F. Giannetti, M. Luise, "The Effect of Signal Quantization on the Performance of Data Receivers for DS/SS-CDMA Transmission Systems", ESA/ESTEC EWP 1755, European Space Research and Technology Centre (ESA/ESTEC), Noordwijk, The Netherlands, December 1993.

In an all-digital implementation of a data modem for Direct-Sequence Spread Spectrum (DS/SS) Code-Division Multiple Access (CDMA) systems, the in-phase and quadrature components of the received signal are usually digitized just after IF matched filtering and baseband conversion. To reduce the processing effort in the data demodulator, it is of interest to represent the signals in the digital domain with as little a number of bits as possible. On the other hand, coarse signal quantization (down to 2-3 bits/sample) causes a non-negligible performance degradation as far as the receiver BER is concerned. The aim of this paper is thus the investigation of the impact of signal quantization on the BER performance of a DS/SS CDMA receiver in the presence of Gaussian noise and co-channel interference. Based on a general theoretical analysis, a few multiple access strategies are taken into consideration, and some simple design hints are derived and verified by computer simulation.

[R7] R. De Gaudenzi, T. Garde, F. Giannetti, M. Luise, "Performance Comparison of Orthogonal Code Division Multiple Access Techniques for Satellite Communications", ESA/ESTEC EWP 1765, European Space Research and Technology Centre (ESA/ESTEC), Noordwijk, The Netherlands, February 1994.

Recently, Code Division Multiple Access (CDMA) techniques have received a great deal of attention for mobile terrestrial/satellite communication systems. Primarily considered for the noteworthy features of low power flux density emission and robustness to interference and multipath, CDMA is known to bear reduced bandwidth and power efficiency when compared to traditional TDMA and FDMA due to the intrinsic co-channel self-noise. Early attempts to increase the capacity of CDMA-based systems for commercial applications relied on voice activation and frequency reuse. More recently, practical solutions to implement (synchronous) orthogonal CDMA signalling are being developed independently in Europe and in the USA. This paper is focused on the comparative performance analysis of those two orthogonal CDMA schemes in the operating conditions of a mobile satellite communications system. In particular, starting from the analysis of the classical additive white Gaussian noise (AWGN) environment, the two CDMA systems are compared in the presence of carrier phase offset, frequency-selective multipath fading, and a typical satellite transponder nonlinearity. As a final implementation aspect, the bit error rate degradation of a quantized digital demodulator with respect to the ideal system is also taken into account.

[R8] R. De Gaudenzi, F. Giannetti, M. Luise, "Optimization of Signal Sense and Code Acquisition for CDMA Receivers", ESA/ESTEC EWP 1792, European Space Research and Technology Centre (ESA/ESTEC), Noordwijk, The Netherlands, August 1994.

Fast and reliable signal sense and signature code synchronization for Direct-Sequence Spread Spectrum (DS-SS) signals are key issues in the design of the receiver for modern packet Code-Division Multiple Access (CDMA) radio networks; this motivates the study of the signal recognition and code acquisition (SR/CA) scheme we describe in this paper. Specifically, starting form elementary estimation theory criteria, we work out a non-coherent parallel SR/CA algorithm that is easily suited to a low-complexity full-digital implementation, possibly in a single Application-Specific Integrated Circuit (ASIC). The results of a theoretical analysis of such a scheme, encompassing Additive White Gaussian Noise (AWGN) and Multiple Access Interference (MAI), are integrated and validated by an overall time-domain system simulation. We also evaluate through a simplified approach the impact of some degradation factors on the overall circuit performance, namely sampling epoch and carrier frequency offset, and one-bit signal quantization, to allow optimization of the design parameters as a function of the characteristics of the received signal.

[R9] F. Giannetti, "Performance of an Asynchronous CDMA Cellular System Operating in the Oxygen Absorption Band", published by Edizioni ETS, Pisa, Italy, October 1994.

In this report a cellular code-division multiple access (CDMA) system operating in the 63-64 GHz band for short-range fixed-to-mobile communications is analyzed. A handful propagation model for the 63-64 GHz band is first introduced and discussed. The system capacity, expressed as the number of users per cell, is then analytically derived and compared with other CDMA schemes operating in conventional frequency bands (i.e. below 2 GHz). Finally, power requirements are derived and the impact of atmospheric conditions is evaluated. It turns out that the use of 63-64 GHz band greatly increases the capacity of asynchronous CDMA (A-CDMA) systems, and reveals suitable for cellular and/or vehicular communications and personal communication networks (PCNs).

[R10] R. De Gaudenzi, F. Giannetti, "DS-CDMA Satellite Diversity Reception for Personal Satellite Communication: Downlink Performance Analysis", ESA/ESTEC EWP 1812, European Space Research and Technology Centre (ESA/ESTEC), Noordwijk, The Netherlands, January 1995.

The downlink of a satellite-mobile personal communication system employing power-controlled Direct-Sequence Code Division Multiple Access (DS-CDMA) and exploiting satellite-diversity is analyzed and its performance compared with a more traditional communication system utilizing single satellite reception. The analytical model developed has been thoroughly validated by means of extensive Monte Carlo computer simulations. It is shown how the capacity gain provided by diversity reception shrinks considerably in presence of increasing traffic or in the case of light shadowing conditions. Moreover, the quantitative results tend to indicate that to combat system capacity reduction due to the intra-system interference, no more than two satellites shall be active over the same region. To achieve higher system capacity, differently from terrestrial cellular systems, Multi-User Detection (MUD) techniques are likely to be required in the mobile user terminal, thus considerably increasing its complexity.

[R11] R. De Gaudenzi, F. Giannetti, M. Luise, "Analysis and Design of a Low-Complexity Adaptive Interference-Rejection Detector for DS/SS CDMA Receiver", ESA/ESTEC EWP 1865, European Space Research and Technology Centre (ESA/ESTEC), The Netherlands, September 1995.

Code Division Multiple Access (CDMA) has emerged as a strong candidate for the air interface of the universal wireless personal communication system planned for the end of the century. In the latest years, a huge research effort has thus been devoted to find new viable techniques to increase the capacity of CDMA radio networks. In particular, different methods to counteract the near-far effect and to diminish the influence of asynchronous Multiple-Access Interference (MAI) have been investigated with the ambition to make CDMA competitive vis-a-vis more conventional access techniques. In this paper, we take into consideration a recently-proposed low-complexity Blind Adaptive Interference-rejection Detector (BAID) scheme that minimizes the detrimental effect of the MAI on the Bit-Error Rate (BER) performance of the data demodulator for Direct-Sequence/Spread-Spectrum (DS/SS) signals. Specifically, we describe a few modifications to the original algorithm that make it more suitable to a practical implementation with QPSK-modulated DS/SS signals and asynchronous multiplexing, and we evaluate the performance of such extended detector in the case of coherent and differential signal detection.

[R12] F. Giannetti, "Capacity Evaluation of a CDMA-Based Wireless LAN", published by Edizioni ETS, Pisa, Italy, April 1996.

This report presents the capacity evaluation of a cellular network using DS/SS-CDMA transmission for wireless local area networks (W-LANs). The capacity, expressed as the number of users per cell, is derived by means of analytical techniques, taking into account for same- and other-cell interference, antenna radiation patterns, synchronous or asynchronous code-division multiplexing and forward error correction (FEC) techniques. The propagation model used takes into account for atmospheric attenuation and it is suited also for the analysis of a W-LAN operating in the millimetre-wave band. The BER is also evaluated, and its sensitivity to cell loading and antenna directivity assessed.

[R13] M. Luise, F. Giannetti, R. Reggiannini, "DSP Techniques for the Design of Digital CDMA Demodulators", ESA/ESTEC P.O. 153177, 31.10.95, Final Report, Consorzio Pisa Ricerche, February 1997.

The widespread diffusion of mobile and personal communication services during the recent years has disclosed new promising perspectives for communication satellites. The unique feature of satellite-based networks to provide continuous wireless coverage to a large number of portable mobile terminals spread over a wide geographical area, gave the spur for the design of new satellite-based communication services. Nowadays, several mobile satellite communication systems are in advanced development status or even close to starting commercial service, and most of them feature Code-Division Multiple Access (CDMA) as transmission/multiplexing technique. The ambitious goal of a global seamless coverage of Earth (or at least of its major economic areas), pursued by all the candidate service providers, is pushing towards the use of complex satellite constellations. However, since most of the satellites are not geostationary, the signal received by an earth-located portable terminal suffers from a non negligible amount of carrier frequency Doppler shift because of the relative satellite-receiver motion. The possible motion of the mobile terminal causes additional Doppler phenomena, and the relative frequency instabilities between the transmitter and the receiver oscillators further aggravate the situation. As an additional degradation factor, the signal received by a ground portable/mobile terminal may be affected by multipath propagation, interference and shadowing, particularly in densely populated urban areas and/or for satellites in visibility at low-elevation angles. Multipath propagation may introduce distortion in the received waveform if the channel delay spread is not negligible with respect to the signaling interval (channel frequency selectivity). Also, the combined effect of the terminal motion and of multipath propagation causes the received signal to be affected by Doppler spread, giving rise to randomly varying attenuation and phase rotation (channel time-selectivity). Since all the impairments outlined above can seriously affect the link performance, some adequate countermeasures are in order. This report investigates the architecture and performance of a mobile satellite CDMA modem suited for application in the abovementioned scenarios. In particular, we give up coherent reception from the outset in view of the difficulties encountered in tracking a time-varying channel, especially when the mobile terminal moves at high speed. We rely instead upon differential encoding/detection (DED) which avoids the need of carrier phase recovery and also provides good resistance versus channel time variability. A further important issue to be investigated pertains to the presence of a frequency offset in the baseband-converted signal at the receiver site. The presence of such an offset is almost inevitable in view of the great difficulty, over the fading channel, to generate at the receiver a stable oscillation, synchronous with the incoming carrier. Therefore a commonly preferred solution is to shift the received signal spectrum in the vicinity of, though not exactly on, the frequency origin, by utilizing at the receiver a free-running oscillator, nominally tuned on the carrier frequency. The residual frequency offset left after this baseband conversion stage may seriously impair the subsequent receiver functions (matched filtering, sampling, data detection etc.). Therefore, either a frequency control loop operating at baseband is to be employed or some measures must be adopted to make data detection least sensitive to the above phenomenon.

[R14] R. De Gaudenzi, F. Giannetti, M. Luise, "Capacity of a Multi-Beam, Multi-Satellite CDMA Mobile Radio Networks with Interference-Mitigating Receivers", ESA/ESTEC EWP 1939, European Space Research and Technology Centre (ESA/ESTEC), Noordwijk, The Netherlands, January 1997.

More and more interference-mitigating algorithms are being investigated in an attempt to increase the capacity of code-division multiple access radio networks. At the moment, the main question about interference-resilient receivers is: do they really bring forth the capacity increase they promise on theoretical grounds ? The aim of this study is to give a preliminary answer to such a question, through the capacity analysis of the forward link ofa multi-satellite, multi-beam, radio communication network at S-band. Specifically, starting from simplified yet realistic assumptions on the beam layout, the antenna footprint shape, and the coding/multiplexing/modulation strategies, it is shown that the blind, adaptive, interference-mitigation receiver, selected as representative of the lot, can indeed boost the system quality of service in terms of outage probability. The results are derived after a mix of theoretical analysis (as far as the detector performance evaluation is concerned) and simulation (to examine a number of different random system configurations) to circumvent the inherent complexity of the issue.

[R15] J. Romero-Garcia, R. De Gaudenzi, F. Giannetti, M. Luise, "A Low-Complexity Adaptive Interference-Mitigating CDMA Detector", ESA/ESTEC EWP 1981, European Space Research and Technology Centre (ESA/ESTEC), Noordwijk, The Netherlands, December 1997.

Code Division Multiple Access (CDMA) with Direct-Sequence/Spread-Spectrum (DS/SS) modulated signals has emerged as a strong candidate for the air interface of the universal wireless personal communication network planned for the end of the century. CDMA radio networks are said to bear a modest overall capacity in terms of number of users/bandwidth, unless tight power control and forward error-correcting codes are used. The main factor that causes such throughput limitation is MAI, that constrains the number of active users operating at a specified system Bit Error Rate (BER). A real breakthrough in this respect was the introduction of the Multi User Detector (MUD), i.e., the optimum receiver for the joint demodulation of all user data streams. One of the main outputs of the vast research activity inspired by the discovery of MUD was recognition that the sensitivity to MAI of CDMA is not inherent to the access method itself, rather it is essentially related to the incorrect utilization in a multiple-access environment of the single-user Correlation Receiver (CR), that actually represents the optimum scheme for the case of a single DS/SS signal in the Additive White Gaussian Noise (AWGN) channel. Despite the impressive amount of investigation on the MUD field, no CDMA system applying this novel demodulation techniques has been demonstrated yet. The present invention deals with an extension of a recently-proposed low-complexity Blind Adaptive Interference-mitigating Detector (BAID) scheme that minimizes the detrimental effect of the Multiple Access Interference (MAI) on the Bit-Error Rate (BER) performance of a CDMA data demodulator. We describe an enhanced version of the original algorithm that makes it robust to the interferers frequency error, more suitable to a practical implementation with symbol-based carrier phase estimation and easily applicable to dual- BPSK-modulated DS/SS signals. Specifically, we show how to make the BAID invariant to a possible carrier phase offset introduced in the front-end of the data demodulator, and we also suggest how to practically enhance the robustness of such detector to asynchronous MAI. The main features of the invention are: 1) adaptive blind detector, i.e., no need for training sequences to help algorithm convergence nor knowledge of interferer parameters: the only parameters required are the useful channel signature sequence and chip timing information as for a conventional detector; 2) robustness to asynchronous CDMA interference even for large interferer power unbalance and carrier frequency offsets; 3) the detector is insensitive to the unknown phase of the useful signal and can adopt conventional BPSK symbol rate phase estimators; 4) increased robustness to the residual baseband useful channel carrier frequency error compared to conventional data-aided Minimum Mean Square Equalizer (DA-MMSE); 5) system performance are very close to the optimum DA-MMSE linear detector in the SNR region of practical interest for a coded system; 6) the adaptive detector can operate at very low SNR typical of a coded system and supports more spectral efficient Dual-BPSK Spread Spectrum signal formats (d-BPSK/SS); 7) well suited for a compact ASIC digital implementation on a user terminal. The invention can find practical applications in the following domains: i) fixed and mobile satellite communication networks; ii) CDMA-based positioning systems; iii) terrestrial CDMA networks.

[R16] G. Gelli, F. Giannetti, A. Napolitano, M. Tanda, "Sistemi OFDM con Applicazione alle Reti WLAN: Caratterizzazione del Canale", (in Italian) Rapporto Progetto PRIN 2000, February 2001.

Parte I: La Propagazione in Ambiente Indoor. Questa parte contiene una descrizione dei modelli del canale radiomobile presentati recentemente in letteratura, con particolare attenzione ai sistemi indoor. Altre tipiche cause di degradazione del segnale, quali errori di fase/frequenza e non linearità sono brevemente passate in rassegna. Parte II: Standard WLAN Basati su OFDM e Modelli di Canale. Questa parte descrive sinteticamente gli standard HIPERLAN 2 e IEEE 802.11a, ed i criteri ed i modelli di canale proposti dall'ETSI/BRAN per la valutazione delle prestazioni di HIPERLAN 2.

[R17] F. Giannetti, "MUSIC System Architecture", Consorzio Pisa Ricerche, Pisa, January 2002.

This document describes the architecture of the MUSIC receiver (Multi-USer and Interference Cancellation) developed according to the specifications issued by the European Space Agency (ESA) The MUSIC project is targeted towards the field of satellite communications for 3G mobile wireless services (S-UMTS) with a twofold goal. On the one hand, it is aimed at demonstrating the feasibility of a single-ASIC (Application Specific Integrated Circuit) implementation of an innovative interference-mitigating technique named EC-BAID, thus paving the way for the development of high-performance low-complexity user terminal equipment suited for S-UMTS. On the other hand, the project is intended to provide a quantitative assessment of the benefits provided by such novel receiver architecture, as far as the QoS of the satellite link in terms of Bit Error Rate (BER) is concerned. This QoS improvement can be read also as a considerable increase in system capacity in terms of number of users supported by the network.

[R18] N.A. D'Andrea, F. Giannetti, V. Lottici, M. Luise, U. Mengali, M. Morelli, R. Reggiannini, "Research Activity Done by the University of Pisa", in the Proceedings of the PRIN 2000 project's final workshop (edited by S. Pupolin), Rome, Italy, December 17-18, 2002, pp. 91-110, published by the University of Padova, Padova, Italy, 2002.

We present hereafter a brief overview of the work we carried out during the project that was focused on Orthogonal Frequency Division Multiplexing (OFDM) transmissions for wireless local area networks (WLANs). Besides many well-known appealing properties, the OFDM technique exhibits some critical aspects, among which we mention first its extreme sensitivity to the nonlinear distortion introduced by high power amplifiers (HPAs) that give rise to intermodulation products. This intrinsic vulnerability of OFDM to nonlinear distortion is to be ascribed to its multicarrier structure as well as to the possible use of amplitude-modulated subcarriers, the above features concurring to heavily randomize the signal amplitude. Therefore, the research activity carried out in the framework of the Task 1, was aimed at the derivation of efficient techniques to counteracting detrimental effects caused by transmitter's nonlinear amplifier on OFDM transmissions over frequency-selective channels. In particular, we investigated an Amplitude and Phase (A&P) predistortion technique which is shown to provide a major enhancement in power efficiency with respect to the unprotected system, as well as a non-negligible gain over alternative linearization strategies. More details about this study are reported in the Contribution to Task 1. Reliable data detection in OFDM transmissions over frequency-selective channels also requires precise channel estimation/equalization and accurate receiver syncronization, especially as far as carrier frequency recovery is concerned. Therefore, the research activity carried out within the framework of Task 2, dealt with the following two topics: channel estimation and frequency synchronization in OFDM terminals for transmissions over frequency-selective channels. Concerning channel estimation, we focused on two pilot-aided schemes: the maximum likelihood estimator (MLE), which is simpler to implement as it needs no information on the channel statistics, and the Bayesian minimum mean square error estimator (MMSEE), which was expected to have better performance as it exploits prior information about the channel. Theoretical analysis and computer simulations have been therefore used to derive performance comparisons between the two estimators. Numerical results showed that for SNR values of practical interest the two schemes exhibit nearly equal performance, provided that the number of pilot tones is sufficiently greater than the length of the channel response. Otherwise, the MMSEE revealed superior performance, but at the expense of a greater implementation complexity. Some comparisons with other algorithms known in the literature have been finally performed. More details about this study are reported in the Contribution to Task 2. Concerning frequency synchronization, the research activity was aimed at the derivation of a non-data-aided (i.e., blind) frequency offset recovery strategy in a severe frequency-selective fading environment. The subject has been tackled through a two-step approach. First, we focused on the estimation and compensation of the fractional part of the frequency offset by means of algorithms not affected by the presence of a subcarrier ambiguity. Next, once the fractional offset was removed from the signal, we proceeded with estimation and compensation of the subcarrier ambiguity. A blind algorithm for the fractional frequency offset estimation has been derived by exploiting the time-frequency domain exchange inherent to the modulation scheme. Actually, due to this feature, a carrier frequency offset has a similar impact on OFDM as a clock timing offset has in a Quadrature Amplitude Modulation (QAM) system. As a consequence, we started considering the Oerder-Meyr's feedforward clock recovery and we re-worked it in order to devise a novel frequency recovery scheme for OFDM, whose performance has been assessed over frequency-selective fading channels. Performance comparison with some algorithms available in the literature has also been carried out. Eventually, we investigated the issue of offset correction. More details about this study are reported in the Contribution to Task 2. A blind algorithm for subcarrier frequency ambiguity resolution over frequency-selective radio channels has been derived starting from a ML approach, whereby the selectivity of the channel was also kept into account. This led to a criterion for the search of the correct frequency alignment that uses a properly shaped windowing of the samples at the receiver DFT output. Simulation results showed a remarkable improvement over other existing techniques, especially at high signal-to-noise ratios. More details about this study are reported in the Contribution to Task 2.

[R19] F. Giannetti, C. Carbonelli, A.A. D'Amico, N.A. D'Andrea, U. Mengali, M. Morelli, R. Reggiannini, "Contribution of the University of Pisa to the PRIN 2002 Project", in the final report of PRIN 2002 project (edited by S. Pupolin) "MC-CDMA: An Air Interface for the 4th Generation of Wireless Systems", pp. 153-173, published by the University of Padova, Padova, Italy, 2005.

Within the Project, the research unit of the University of Pisa conducted extensive research on transmission/multiple access techniques for 4G wireless networks, with special emphasis on MC-CDMA applied to cellular scenarios and derived the relevant performance figures in terms of error rate, outage probability and cell capacity. Furthermore, the issues of channel estimation and interference cancellation form MC-CDMA have been addressed. Moreover, an algorithm for the estimation of directions of arrival at the base station was also derived and successfully employed for the implementation of a novel technique for locating and tracking a mobile terminal inside a cell.

THESIS

[T1] F. Giannetti, "Applicazioni dei Codici a Blocco per la Correzione di Pacchetti di Errori", (in Italian) Electronic Engineering Master Degree Thesis, Pisa, Italy, June 1989.

Nel presente lavoro viene esaminato l'impiego di un codice correttore di pacchetti di errore nella trasmissione su ponte radio delle trame della gerarchia SONET, individuandone le possibili collocazioni entro la struttura di trama e valutandone le prestazioni ottenibili. L'interesse di questo studio deriva dal crescente impiego di codici per correzione d'errore, dall'originalita' della soluzione proposta che colloca il codice direttamente entro la trama e dalle prospettive di affermazione del SONET come standard internazionale nel prossimo futuro.

[T2] F. Giannetti, "Sistemi di Comunicazione con Accesso Multiplo a Divisione di Codice", (in Italian) Electronic Engineering Doctorate Thesis, Padova, Italy, February 1993.

Gli ultimi anni sono stati caratterizzati da una crescente domanda di sistemi di radiocomunicazione digitale in grado di offrire all'utenza una piu' marcata diversificazione dei servizi, migliore qualita' e maggiori capacita' di traffico. Come conseguenza, e' stato dato un forte impulso allo sviluppo ed alla diffusione di sistemi di radiocomunicazione, quali i sistemi radiomobili, i sistemi di comunicazione personale (PCN) e la diffusione di programmi radiotelevisivi (broadcasting) da satellite. In questo contesto si fa sentire sempre piu' forte l'esigenza di studiare e di proporre soluzioni nuove in grado di soddisfare alle sempre crescenti richieste da parte dell'utenza. Il progetto di nuovi sistemi di radiocomunicazione si presenta come un compito impegnativo anche perche' ci si deve confrontare con il crescente affollamento delle frequenze radio, con il conseguente aumento del livello di interferenza e con i canali di propagazione caratterizzati da effetto Doppler, cammini multipli, fenomeni di fading e di oscuramento. Le soluzioni proposte per quanto riguarda le tecniche di trasmissione e di multiplazione da impiegare nei nuovi sistemi di comunicazione dovranno percio' essere improntate alla massima resistenza nei confronti di interferenze e disturbi di canale. Esse dovranno altresi' garantire un elevato grado di flessibilita' per quanto riguarda l'allocazione di nuovi canali in vista di possibili future espansioni del sistema, stante l'attuale tendenza di crescita del settore, ed offrire un efficiente utilizzo di risorse quali la banda di frequenza e la potenza.

PATENTS

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TEXTBOOKS (in Italian)

[X1] F. Giannetti, M. Luise, R. Reggiannini, "Esercizi e Complementi di Teoria dei Segnali", Servizio Editoriale Universitario, Pisa, Italy, March 1996.

[X2] E. Amodei, A. D'Andrea, F. Giannetti, "Guida alle Esercitazioni Sperimentali di Comunicazioni Elettriche", Edizioni ETS, Pisa, Italy, March 1996.

[X3] E. Amodei, A. D'Andrea, F. Giannetti, "Guida alle Esercitazioni Sperimentali di Comunicazioni Elettriche - Manuale per l'Istruttore", Edizioni ETS, Pisa, Italy, March 1996.

[X4] F. Berizzi, G. Corsini, F. Giannetti, M. Luise, G.M. Vitetta, "Esercizi di Teoria dei Segnali", Edizioni ETS, Pisa, Italy, May 1996.

[X5] F. Giannetti, M.V. Greco, L. Verrazzani, "Appunti di Comunicazioni Elettriche", Edizioni ETS, Pisa, Italy, 2000.

[X6] F. Giannetti, F. Lombardini, M. Moretti, L. Sanguinetti, "Esercizi di Sistemi di Telecomunicazione", Edizioni ETS, Pisa, Italy, 2005.

RADIOASCOLTO, STORIA DELLA RADIODIFFUSIONE, DIVULGAZIONE (in Italian)

[H1] F. Giannetti, "Il Servizio di Diffusione Radiotelevisiva per le Forze Armate USA", Radiorama, 1-2001, pp. 7-8.

Il Ministero della Difesa (Department of Defense, DoD) degli Stati Uniti dispone di un servizio di diffusione radiotelevisiva per il proprio numeroso personale sparso in varie (e spesso remote) località di tutto il mondo. Si tratta di una vera e propria rete globale capace di servire circa 1.000.000 di persone, tra dipendenti militari e civili, con i rispettivi familiari, dislocati in oltre 150 paesi o imbarcati su navi della marina militare. Il servizio radiotelevisivo militare trasmette sia produzioni proprie, realizzate in appositi studi presso installazioni negli Stati Uniti o all'estero, che programmi ripresi dalle principali reti private statunitensi o da enti del servizio pubblico come la National Public Radio (NPR). I programmi comprendono principalmente notizie, sport e intrattenimento in puro stile USA ("a touch of home"), ma anche informazioni di servizio riguardanti la vita militare o i vari eventi sociali che occupano il tempo libero nelle basi USA, come ad esempio gare sportive amatoriali, iniziative di beneficienza, attività di volontariato ecc.. Il servizio di radiodiffusione per i militari USA è una struttura assai complessa che si articola in vari organismi. Il coordinamento e comando è affidato ad un ente, denominato Army Broadcasting Service (ABS) [1], il quale svolge attività di direzione operativa e di gestione delle risorse per le varie stazioni e reti radiotelevisive militari operanti al di fuori del territorio continentale degli Stati Uniti. L'ABS gestisce le seguenti cinque reti di diffusione regionale: American Forces Network Europe (AFN-E) che è la più grande e serve il continente europeo ed il bacino del Mediterraneo, AFN-Honduras, AFN-Alaska, American Forces Korea Network e Central Pacific Network. Il principale compito operativo dell'ABS consiste nel fornire alle varie stazioni radiotelevisive militari americane sparse nel mondo un adeguato supporto durante l'installazione degli apparati satellitari per la ricezione dei programmi provenienti dagli Stati Uniti e che dovranno essere poi rediffusi ai militari dislocati all'estero. In estrema sintesi, l'ABS fornisce risorse, sia umane che materiali, per la diffusione radiotelevisiva.

[H2] F. Giannetti, "Worldspace: la Radio Direttamente dal Satellite", Radiorama, 4-2001, pp. 10-13.

WorldSpace è una società fondata nel 1990 da Noah A. Samara con lo scopo di fornire attraverso il mezzo satellitare una grande quantità di programmi radiofonici contenenti informazione, cultura e intrattenimento per quelle popolazioni che vivono nelle aree meno sviluppate del pianeta e quindi sono poco (o per niente) servite dai comuni mezzi comunicazione radiotelevisivi. Per raggiungere un così ambizioso obiettivo, rivolto a tre quarti della popolazione mondiale, WorldSpace si è affidata alle più moderne tecnologie digitali nel campo della radiodiffusione da satellite, sviluppate in cooperazione con alcune industrie leader mondiali dell'elettronica e delle telecomunicazioni, tra cui Alcatel Space, Fraunhofer Institut Integrierte Schaltungen, Micronas Intermetall, Matra Marconi Space, e STMicroelectronics. La produzione dei ricevitori portatili è stata invece affidata a marche del calibro di Hitachi, JVC, Panasonic e Sanyo. Le principali tappe dell'avventura umana ed imprenditoriale del 'sognatore' Samara sono brevemente ripercorse in un articolo consultabile sul sito di Radio Nederland Wereldomroep (RNW).

[H3] F. Giannetti, "La Voce del Tatarstan", Radiorama, 6-2001, pag. 8.

La Repubblica del Tatarstan è una repubblica autonoma situata nella parte centro-occidentale della Federazione Russa: la figura 1 ne mostra l'esatta posizione geografica. Il suo teriritorio si trova in corrispondenza della confluenza dei fiumi Volga e Kama ed è mostrato con maggior dettaglio in figura 2 insieme alle regioni circostanti. La Repubblica del Tatarstan si estende per 67.836 chilometri quadrati ed ha una popolazione di 3.766.500 abitanti, in massima parte Tatari e Russi, ma con una ricca presenza di minoranze etniche in rappresentanza di oltre 70 nazionalità. La capitale è la città di Kazan che conta 1.200.000 abitanti. Dal Tatarstan opera l'emittente radio "Tatarstan Awazy" ("Voce del Tatarstan") che trasmette in onde corte e onde lunghe programmi destinati alla numerosa comunità Tatara dispersa negli stati della ex-Unione Sovietica.

[H4] F. Giannetti, "Radio in Italiano: Il Caso Germania", Forum Italradio 2006, Firenze, 27 Gennaio 2006.

[H5] F. Giannetti, "La Radiodiffusione Italofona in Germania", Italradio - Rivista di radiofonia in lingua italiana, ISSN 1973-7920, Anno 2, No. 2, Inverno 2006, pp. 21-50.

L’anno appena trascorso ha rappresentato un’eccezionale ricorrenza per quanto riguarda la storia della radiodiffusione italofona in Germania. Il 2005 è stato infatti celebrato il 60-esimo anniversario della fine della II Guerra Mondiale, con la quale si concluse l’epoca delle trasmissioni di propaganda nazi-fascista irradiate in italiano dal suolo del Terzo Reich fin dagli anni ‘30 del XX secolo. Le trasmissioni di propaganda politica sarebbero poi riprese negli anni ‘50, nel nuovo scenario internazionale caratterizzato dalla contrapposizione tra Est ed Ovest che aveva proprio nella Germania, divisa in due, la sua rappresentazione più palese e drammatica. Ma il 2005 ha rappresentato anche il 50-esimo anniversario di un altro fondamentale avvenimento che ha marcato in modo decisivo la storia della radiodiffusione in lingua italiana in Germania. Il 20 Dicembre 1955, a Roma, il presidente del consiglio dei ministri italiano Alcide De Gasperi ed il cancelliere tedesco Konrad Adenauer firmarono l’accordo italo-tedesco di reclutamento di manodopera, con il quale si aprirono le porte della Repubblica Federale Tedesca (RFT) ai lavoratori italiani. Grazie a questo accordo, il numero di Italiani residenti in Germania crebbe rapidamente e nel giro di qualche anno anche le emittenti radiofoniche pubbliche tedesche dovettero adeguarsi a questa nuova realtà sociale attivando varie trasmissioni in lingua italiana rivolte ai lavoratori immigrati, alcune delle quali sono tutt’ora operative. A cinquant’anni da quel fatidico 1955, intendiamo ripercorrere le principali tappe storiche e fare il punto sullo stato attuale della radiodiffusione in lingua italiana in Germania. Data la diversa tipologia di contenuti e di “target” di ascolto, le trasmissioni di propaganda, e più in generale quelle a carattere politico-informativo saranno trattate separatamente rispetto a quelle per gli immigrati. Le prime, progressivamente chiuse dalla caduta del Muro di Berlino in poi, sono attualmente del tutto scomparse, mentre le seconde, sia pure in mezzo a molte difficoltà, sono attive ancora oggi e cercano di mantenere vivo il contatto con la numerosa comunità degli Italiani di Germania.

[H6] F. Giannetti, "50 Anni di Straordinari Progressi nello Spazio", Programma radiofonico in due puntate realizzato per l'emittente "La Voce della Russia", trasmesso il 2 e 3 Ottobre 2007, replicato il 4 e 5 Ottobre 2007.

1^ Puntata: Testo, Audio
2^ Puntata: Testo, Audio

[H7] F. Giannetti, "Radio in Italiano via Satellite", Forum Italradio 2007, Firenze, 23 Novembre 2007.

[H8] F. Giannetti, "60 Anni di Evoluzione nelle Tecnologie delle Telecomunicazioni: dalle Valvole ai Videofonini", Convegno internazionale "60 Anni di Radio tra Voi", Negli atti del convegno internazionale "60 Anni di Radio tra Voi" svoltosi a Capodistria, Slovenia, il 29 Maggio 2009, pubblicati da RTV Slovenija-Radio Capodistria, 2011, pp. 37-40. ISBN 978-961-92841-1-7.

[H9] F. Giannetti, "L’Italiano nel Panorama Mondiale della Radiodiffusione: Emergenza Linguistica o Lingua Emergente?", Forum Italradio 2009, Firenze, 12 Novembre 2009.

[H10] F. Giannetti, "Marconisti: storie di uomini, tra le onde radio e le onde del mare", Recensione del ciclo di 5 puntate intitolato Marconisti trasmesso da RAI Radio 3 tra il 22 ed il 27 Marzo 2010, pubblicata su Italradio - Rivista di radiofonia in lingua italiana, ISSN 1973-7920, Anno 6, No. 11, pp. 47-49

[H11] F. Giannetti, "Forte Dei Marmi: Ricordo dell'ammiraglio Morin", Italradio - Rivista di radiofonia in lingua italiana, ISSN 1973-7920, Anno 7, No. 12, Gennaio-Aprile 2011, pp. 41-45.

Forte dei Marmi ha dedicato la scorsa estate una mostra all'ammiraglio Morin (Genova, 15 maggio 1841 - Forte dei Marmi 13 settembre 1910) nel centenario della morte del ministro della Marina e degli Esteri all'inizio del Novencento e destinatario del telegramma con cui Marconi assegno' all'Italia il libero utilizzo della radio.

[H12] F. Giannetti, "Vecchia Radio, Nuova Radio: Idee, Desideri e Sogni per la Tecnologia della Radio del XXI Secolo", Forum Italradio 2011, S.M. di Galeria (Roma), 26 Novembre 2011.

[H13] F. Giannetti, "Vecchia Radio, Nuova Radio: le Tecnologie per la Radiodiffusione del XXI Secolo", convegno "1a Giornata Mondiale della Radio: Trasmettere e ascoltare, per una diffusione davvero universale", Pisa, 13 Febbraio 2012.

[H14] L. Cobisi, F. Giannetti, P. Morandotti, "Pillole di Radio", Programma radiofonico in 16 puntate realizzato per la "Radio della Svizzera Italiana", trasmesso nel mese di settembre 2012 (Podcast).

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[H15] F. Giannetti, "18 Modi di Ascoltare la Radio: Come Orientarsi (o Disorientarsi)", Negli atti del Forum Italradio 2012 svoltosi a Lugano (Svizzera), il 21 Settembre 2012, pubblicati su Italradio - Rivista di radiofonia in lingua italiana, ISSN 1973-7920, Anno 9, No. 15, pp. 23-28

Sono presentati i vari modi di ascoltare la radio in formato analogico e digitale, mettendo in evidenza vantaggi e svantaggi di ciascuna modalita', seguendo un percorso storico e tecnologico.

[H16] F. Giannetti, S. Selleri, "Stazione Radio Dimostrativa per Trasmissioni Sperimentali a Bassissima Potenza in Onde Medie", Giornata Mondiale della Radio 2013, Firenze, Hotel Mediterraneo, 14 Febbraio 2013.

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