Performance analysis and comparisons of different ultra-wideband multiple access modulation schemes

The multiuser performance of two kinds of ultra-wideband (UWB) systems, namely, multi-carrier frequency-hopping-UWB and time-hopping-UWB, is evaluated. We derive the bit error rate of these systems in both AWGN and fading channels. Our numerical results show that the TH-UWB system always outperforms the MC-FH-UWB system with non-coherent detection. However, the MC-FH-UWB system with coherent detection presents a better performance than TH-UWB in a very few cases. Then, we use a practical low-rate convolutional error correcting code, which does not require any extra bandwidth further than that needed by the uncoded scheme, to improve the system performance. The results show that the coded scheme significantly outperforms the uncoded scheme in both AWGN and fading channels. Furthermore, the results indicate that, like in the uncoded scheme, in the coded scheme the TH-UWB system performs better than the MC-FH-UWB system