Performance Analysis for DS-SSMA using Convolutional Codes and Diversity in Nakagami Fading Channels

• Main Authors: Kuo, Hsi Chen, 郭喜振
• Other Authors: Wu, Kou Tan
• Format: Others
• Language: en_US
• Published: 1994
• Online Access: http://ndltd.ncl.edu.tw/handle/17941462917549853843

碩士 === 國立中正大學 === 電機工程研究所 === 82 === In mobile communications, multipath fading is a fundamental limitation to system performance and spread spectrum is a well- known technique to combat interference. CDMA technique is clai- med to increase the capacity by 20 times compared with the FDMA and about 4 times compared with the TDMA. With the high growth of wireless service, a third-generation wireless system begins to adapt code division multiple access technique. In this thesis, DS-SSMA with BPSK and QPSK modulation in Nakagami fading channels is considered. The primary interest is in the evaluation of average error probability, outage probabi- lity and irreducible error probability. Two approximation meth- ods are employed to evaluate these probabilities. One method is the Gaussian quadrature rule, and the other is the series expa- nsion method. Moreover, convolutional code and diversity are used to improve the performance. Fairly general upper bound on the convolutional codes and hence on the bit error probability are used. It is found that convolutional codes can improve the performance when the fading is not severe; the diversity can improve performance at deep fade but shows no improvement when when fading is not severe. Results also indicate that the com- bination of convolutonal codes and diversity is more effective in mitigating multipath fading. CDMA environments shown to be interference-limited.