Performance Analysis of Time-Hopping Ultra-Wideband Systems in Multipath Fading Channels (Uncoded and Coded Schemes)

In this paper, the performances of both uncoded and coded multiple access TH-UWB systems, introduced in [1-3] in multipath Rayleigh fading channels, are evaluated. The receiver is a selective diversity combining receiver, known as SRake. Based on a Gaussian distribution assumption for the multiple access interference at the output of the SRake receiver and by using a virtual branch technique, as introduced in [4,5], the bit error rates for uncoded and coded schemes are derived. The performance analysis shows that the effective order of diversity achieved by the coded scheme is the product of the number of branches of the SRake receiver and the Hamming distance of the code applied. Furthermore, the results indicate that the coded scheme significantly outperforms the uncoded scheme without requiring any extra bandwidth, further than what is required by the uncoded system.