Exact modeling of multiple access interference, ber derivation and a method to improve the performance of UWB communication systems

Abstract

The scope of this work is to evaluate the performance of ultra-wideband (UWB) communication systems, and to find methods to improve the performance. In this work, exact statistical models for the multiple access interference in TH-PPM, TH-PAM, and DS-PAM UWB systems are derived under AWGN channel. Based on these models, using characteristic function method, the BER performances of these systems are expressed in simple formulas. These models are extended for multipath fading channels with single correlator receiver to find an approximate solution for the BER performance. Analytical results are verified by computer simulations. In the final part of the thesis, a transmit diversity scheme is introduced to improve the UWB system performance. It is based on coherent combining of signals in space. The proposed transmit diversity scheme shows significant advantage in performance and reduces the receiver complexity. Performance of the proposed scheme is compared with few other systems.