Performance Analysis and Evaluation of Multi-User Coded Hybrid Spread Spectrum System using Improved Chaotic Sequences

Abstract

Although spread spectrum technique is considered as an old technique, however it still has wide applications in designing reliable and secure communication systems. Due to the recent developments, it becomes not sufficient to full fill all the security and applications requirements, especially from the point of view of the spreading codes. As an alternative solution, chaotic spreading codes appeared to solve most of the problems of the traditional spreading codes. Chaotic codes have better properties from the security point of view. Also, chaotic maps can be used to produce a huge number of sequences; this feature is very desirable in the applications of the multiple accesses. In this paper, the performance of a multi-user hybrid spread spectrum system is presented, an analysis and evaluation of the presented system is performed under fading channel. The system is coded with Viterbi decoder, and has three types of spreading techniques. A performance analysis, evaluation and comparison are performed between different types of improved chaotic codes and Pseudo Noise codes as spreading codes in the Direct Sequence Spread Spectrum. The results show that the chaotic codes give better performance than the Pseudo Noise codes.