Multi-User Performance Issues in Wireless Impulse Radio Networks

摘要

There has been a growing interest in Ultra Wide Band (UWB) communication technologies over the last ten years. Motivated by advances in narrow pulse generation techniques and the potential for VLSI digital receivers, much fundamental research has been devoted to UWB. Most of the research to date has been dedicated to the potential for dense multi-user environments, narrow band interference issues, and multi-path considerations. While Impulse Radio (IR) has shown tremendous potential for high throughput local area networks based on time domain separation techniques, the stringent parametric assumptions required for practical implementation have not been clearly evaluated. Specifically, two of the more common constraints required to meet the projected UWB performance measures are timing tolerances and multi-user interference control. The work here has addressed both of these critical issues. Our work is the first to quantify the effects of timing jitter and tracking on time-hopping UWB multi-user performance. The investigations of these issues show that the performance of binary and 4-ary impulse radio is very sensitive to timing jitter and tracking errors. Supported multi-user performance is quantified through simulation and finds orthogonal pulse position modulation (PPM) out performed binary offset PPM at all jitter levels in thermal and pulse noise. We also compare accepted narrowband tracking techniques to an efficient error tracking method adapted to UWB.