Study On Multiple Access Technology In UWB Wireless Communication System

Ultra-wide band (UWB) systems have received wide attention both in the U.S. and in Europe. These systems make use of ultra-short duration (<1 ns) pulses which yield a bandwidth on the order of gigahertz signals characterized by extremely low power spectral densities. UWB systems are particularly promising for short-range wireless communications as they potentially combine reduced complexity with low power consumption, low probability of intercept (LPI) and immunity to multi-path fading. The successful deployment of the UWB technology depends strongly on the development of the efficient multiple-access (MA) techniques. The major purpose of investigating the MA techniques is to resolve how to make more people to share the finite frequency resources. The basic idea composes of making the capabilities of systems the largest by reasonably assigning and employing some frequency resources.The MA techniques of UWB are our content. We compare the performance between the TH-UWB scheme and the DS-UWB scheme by simulation, and the results show that the DS-UWB scheme is better than TH-UWB both in capability and in Bit Error Rate (BER). Then we introduce another two methods to implement MA using pseudo-chaotic time hopping multiple access (MA-PCTH) and multistage frequency hopping multiple access (MS/UWB FHMA), and emphasize their principles. When we investigate the MS/UWB FHMA, we compare the BER in three detection algorithms by simulation, and give the optimized method.