Statistical Analysis and Performance Comparison of Improved and Optimized CSC using Different Chaotic Maps under Different Fading Channels

摘要

Spread spectrum technique becomes one of the most important secure communication techniques in the recent decades. One of the most important parameter in spread spectrum is the spreading sequence, especially in the direct sequence spread spectrum. Due to the huge increase in the applications and the demanded users, the traditional spreading codes become not sufficient to fulfill the development requirements. As an alternative solution, the chaotic codes appeared to solve most problems of the traditional spreading codes. Recently, many researches focused on the chaotic codes, due to its attractive security properties, in addition to its availability to generate a huge number of spreading codes, which is very useful in the multi-access applications. However, as the number of the multiple access interference is increased, the performance of the chaotic codes is degraded. One of the degradation reasons is the assigning of the initial condition of the chaotic map. This paper presents a comprehensive statistical analysis of an improved and optimized chaotic sequence code. In addition to the traditional chaotic code; the analysis is performed over improved codes such as the self-balanced, the zero mean, and the self-balanced zero mean chaotic code. The spreading chaotic codes are generated from optimized maps with optimum initial conditions. The analysis consists of the balance, orthogonality, the normalized maximum autocorrelation side lobe, and the normalized average cross correlation property. In addition, the performance of the mentioned code is evaluated and compared with the Gold code for different code lengths over different fading channel.