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在无法获得稳定的全网同步特殊情况下,异步DS-CDMA系统是一种维持通信网络畅通的有效途径。该文首先分析了异步DS-CDMA多用户系统下多用户干扰(MAI)产生机理以及对系统性能带来的影响,在仿真环境下建立了异步DS-CDMA多用户系统模型,然后对三种扩频序列的相关特性进行仿真分析。比较分析了不同接入时延误差和不同失步用户数两种情况下,系统使用不同扩频序列时在AWGN信道下的误码率特性。分析表明,混沌序列是更加满足异步DS-CDMA系统的扩频序列,论文结果对可靠通信系统研究具有参考价值。
Asynchronous DS-CDMA system is an effective way to maintain the smooth communication network under the condition of not being able to obtain stable whole network synchronization. In this paper, the mechanism of multi-user interference (MAI) and the impact on system performance under asynchronous DS-CDMA multi-user system are analyzed firstly. Asynchronous DS-CDMA multi-user system model is established under the simulation environment, Frequency sequence of the relevant characteristics of simulation analysis. The bit error rate (BER) performance under AWGN channel with different spreading sequences is compared under different situations of different access delay errors and different number of out-of-step users. The analysis shows that the chaotic sequence is more satisfactory for the spreading sequence of the asynchronous DS-CDMA system. The results of the dissertation have a reference value for the research of reliable communication system.