Code Shift Reference Impulse Based Cooperative UWB Communication System

Abstract: Ultra wideband (UWB) is a radio technology in which the transmission of information is done over a large bandwidth with very short pulses at low energy levels. UWB technology has gained a high popularity in the field of short-range wireless communications. UWB provides significant benefits like position location capability, reduced fading effects, and higher channel capacity. UWB technology is very desirable because of its certain characteristics like low power consumption, cost reliability and simple architecture. However, UWB systems face challenges regarding system design to achieve low complexity and low cost. UWB systems need high sampling frequencies and face problems while using digital signal processing technology. In this thesis, first, the comparison of transmitted reference (TR), multi-differential frequency shifted reference (MD-FSR) and code shifted reference (CSR) is done in terms of BER performance and system complexity. The simulation results validate that the CSR-UWB system has better BER performance and lower complexity than MD FSR-UWB system. Secondly, cooperative communication is implemented for CSR-UWB. The system BER performance of the CSR impulse-based cooperative UWB communication system is evaluated for different number of relays and different average distances between source node and destination node. The simulations are carried out under both line of sight (LOS) and non-line of sight (NLOS) environments. The simulation results show that the performance of the system decreases with the increase in average source-to-destination distance. We also observe that the system performs better under an environment of LOS channel than under an environment of NLOS channel. Finally, the results validate that the system performs better as the number of relay nodes increases until it reaches an adequately large number.