Multiple access performance of UWB M-ary impulse radio systems with diversity reception

Impulse radio (IR) is based on ultra-wideband (UWB) time-hopping spread spectrum technology. The influence of temporal and spatial diversities on the multiple access performance of M-ary pulse position modulation (PPM) IR systems in multipath environments is analyzed. We investigate the used of an antenna array at the receiver to improve the multiple access performance of the system in terms of the number of active users supported by the system for a given bit error rate and bit transmission rate. Numerical results show that the bit error rate performance and multiple access capacity of the M-ary IR system can be improved by increasing the number of antenna array elements and selected multipaths at the receiver.