为了提高扩频通信系统的性能,设计分数阶混沌扩频通信系统.采用Adomain分解算法求解分数阶简化Lorenz系统,推导分数阶系统迭代式,得到系统的数值解.对迭代值进行简单的二值量化,生成多组互不相关的混沌伪随机序列.将混沌伪随机序列作为扩频码应用于扩频通信系统.在不同信噪比时,分析不同扩频码对通信系统性能的影响.研究结果表明:基于分数阶简化Lorenz系统生成的伪随机序列更随机,均通过美国国家科学技术研究所(NIST)的统计测试套件(STS)测试,序列的生成速度快;与整数阶混沌系统相比,分数阶扩频系统具有更大的秘钥空间,具有更好的安全性;分数阶混沌扩频通信系统的性能优于Hénon映射、Chen系统、m序列及Gold序列的性能,并且具有更大的多址容量.%In order to improve the performance of the spread spectrum communication system, a fractional-order chaotic spread spectrum communication system was designed. The fractional-order simplified Lorenz system was solved by adopting Adomian decomposition method. The iteration of the fractional-order system was deduced, and the numerical solution was obtained. Several uncorrelated chaotic pseudo-random sequences were generated by a simple binaryzation algorithm for iterative results. The pseudo-random sequence was used as spread spectrum code in spread spectrum communication system. At different signal-to-noise ratios, the influence of different spread spectrum codes on the performance of the communication system was analyzed. The results show that the pseudo-random sequences based on the fractional-order simplified Lorenz system have good randomness, and all pass statistical test suite(STS) of National Institute of Science and Technology(NIST).The generation of these pseudo-random sequences is fast. They have bigger secret key space and better security than the integer-order counterpart. The performance of the spread spectrum communication system designed is better than that of Hénon map, Chen system, m-sequence and Gold sequence, and has a good multiple access capability.
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