Exact BER Performance of RQAM in TAS/MRC Diversity over Arbitrary Nakagami-m Fading Channels

• Main Authors: Ta-Li Liao, 廖大利
• Other Authors: Ching-Tai Chiang
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/92427890935253479117

碩士 === 義守大學 === 電機工程學系碩士班 === 96 === In this thesis, we derive a simple expression of exact bit error rate (BER) performance in a closed-form for rectangular QAM (RQAM) in the TAS/MRC scheme over arbitrary Nakagami-m fading channels. The QAM technique becomes attractive due to the high bandwidth efficiency. Thus, the 16-QAM and 64-QAM technique are adopted for the WiMAX systems. In addition, an integration of selection combining (SC) at the transmitter and maximum-ratio combining (MRC) at the receiver (labeled TAS/MRC) has been proposed to answer the demand of ever increasing spectrum efficiency. The quotation of Nakagami model lies in its general physical description for both severe and weak fading. With specified bandwidth efficiency and BER performance as the system guidance, the analytical results are helpful to evaluate the required constellation size of RQAM and the infrastructure of the TAS/MRC scheme under the impact of arbitrary Nakagami-m fading channels. The analytical BER results deduce that the M-ary square QAM system outperforms the I*Q rectangular QAM system for the same constellation size. Similarly, the I*Q rectangular QAM system with the combination of closet size for I and Q achieves the best BER performance. By the way, the advantage of diversity becomes clearer over the severe fading channels. All the analytical results are verified by Monte Carlo simulations.