Spatiotemporal chaotic sequences for asynchronous DS-UWB systems

In this study, we address the effect of spreading sequences on the performance of asynchronous direct-sequence (DS) ultra-wideband (UWB) systems. We consider the two cases of short and long sequences in a multipath environment. In particular, we propose the use of sequences generated with a family of spatiotemporal chaotic systems, namely Piecewise Coupled Map Lattices (PCML), as spreading sequences. Such sequences are shown to reduce the MUI variance with regard to i.i.d. and Gold sets for both short and long sequences. Furthermore, simulation results show that the use of long PCML codes improves the average bit error rate (BER) of the system, which hence can accomodate more active users.