A simulation comparison of time-hopping PAM and interference suppressing OFDM in multiuser ultra wideband communications systems

In this paper we present a side-by-side comparison between time-hopping (TH) impulse radios (IR) based on pulse amplitude modulation (PAM) and interference suppressing (IS) OFDM-based ultra wideband (UWB) systems in multi-user scenarios. For both systems we use minimum mean squared error (MMSE) receivers, and look at the raw bit error rate (BER) at the physical layer as performance criterion. This is evaluated using simulations for various scenarios that include additive white Gaussian noise (AWGN), multipath and/or multiple access interference, and narrowband interference. Numerical results indicate that in the presence of AWGN only, the two systems display similar performance, while for multipath propagation the TH-PAM IR system outperforms the IS-OFDM system. However, in the presence of narrowband interference the IS-OFDM system outperforms the TH-PAM IR system which displays poor performance in this case.