Performance analysis of DS/SSMA with error correcting code in Rayleigh fading channel

In this paper, we analyze the bit error rate (BER) performance of DS/SSMA with error correcting code in Rayleigh fading channel. We derive an upper bound on the BER by Chernoff bound approximation and the Gaussian assumption of the variance of interferences. The bound is much similar to the one derived for a trellis coded MPSK system, therefore, the performance improvement of DS/SSMA may be determined by the result obtained for a trellis coded MPSK system. Motivated by this, we propose a system with repetitive code in conjunction with error correcting code. As the repetitive code increases the order of time diversity, we can improve the performance. As a result, it is shown that the proposed system can increase the maximum number of allowable transmissions to twice of that previously estimated for fading channel