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Receiver architectures and ranging algorithms for UWB sensor networks

Prof. Umberto Mengali
Dipartimento di Ingegneria dell'Informazione: Elettronica, Informatica, Telecomunicazioni, Università di Pisa

12 hours, 3 credits

May 2 - May 5, 2011

Dipartimento di Ingegneria dell'Informazione: Elettronica, Informatica, Telecomunicazioni, via Caruso, meeting room, ground floor

Abstract

Ultra-wideband (UWB) radios have relative bandwidths larger than 20% or absolute bandwidths of more than 500 MHz. These features offer many potential advantages including: (i) low interference to and from other systems; (ii) low sensitivity to fading; (iii) accurate position location and ranging due to the fine time resolution; (iv) easier material penetration.

Interesting applications of UWB are in the area of sensor networks, where low-to-medium rate communications and position capabilities are combined for monitoring and control purposes. UWB signaling is very suitable in this context as it allows centimeter accuracy in ranging and promises the realization of low-power and low-cost communication systems.

The achievement of the above goals, however, poses a number of technical challenges. Indeed, whereas low-complexity transmitters are quite feasible with current technology, there are a number of processing tasks that, as a consequence of the large signal bandwidth, make the implementation of the receivers and of the ranging operations extremely complex.

For example, a fully digital receiver requires signal sampling at Nyquist rate, which may be in the order of the GHz. Analog-to-digital converters working at such a rate are expensive and power consuming. On the other hand, analog receivers may require wideband delay lines that are very difficult to implement in integrated form. Finally, very sophisticated algorithms are needed to perform signal synchronization and ranging measurements with nanosecond accuracy.

The aim of this series of lectures is to review the problems encountered in the implementation of UWB receivers and in the design of synchronization and ranging algorithms.

Syllabus

FCC emission regulations
UWB channel model
UWB signaling formats
Optimum and suboptimum receivers
Synchronization algorithms
Time-of-arrival estimation
Estimation bounds
Localization algorithms