PERFORMANCE EVALUATION OF TRANSMITTED REFERENCE, FREQUENCY-SHIFTED REFERENCE AND CODE-SHIFTED REFERENCE MULTI-USER UWB SYSTEMS
Ultra wideband (UWB) is based on transmission with very short pulses of low energy. The use of UWB technology will increase in the fields of wireless communication in the near future. The wider bandwidth of UWB technology has several advantages such as excellent penetration ability, multi-user support and high channel capacity. UWB has many applications due to its low power consumption, low cost and low interference. UWB poses design challenges for low power and low complex systems at wider bandwidth. For digital systems, it also requires high sampling rate and intensive computation to estimate gain and delay of multipath channel. In this thesis, the performance of non-coherent transmitted- reference (TR), frequency-shifted reference (FSR) and code-shifted reference (CR) systems are compared with the orthogonal Gold code (OG) code reference (CR) systems for single and multi-user for low data rates. First, the performance of non-coherent receivers for single-user system working in residential line of sight (LOS) is evaluated. The results and performance comparisons are presented for TR, FSR, CR and OG-CR systems. Secondly, the performance comparison of TR, FSR, CR and OG-CR are presented in multi-user environment. The simulation results validate that CR and OG-CR have better performance than TR and FSR in multi-user environment. Finally, results show that CR shows better performance than OG-CR for few users and almost same performance as OG-CR at high SNR with more number of users.
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