基于完全伸展映射混沌二值序列的设计

Designing of chaotic binary spreading sequences based-on fully stretching piecewise-linear maps

混沌序列具有相关性好、数目众多等特点,很适合作为DS-CDMA系统中的扩频码。文中对基于完全伸展的分段线性映射进行了设计,得到了自相关函数为符号交替、负指数衰减的混沌二值序列,理论分析表明该序列相对于独立同分布的纯随机序列可以提高15.5%的系统容量。在matlab中将这种序列作为异步DS-CDMA的扩频码进行系统误码率仿真,仿真结果与理论分析一致,这种序列非常适合做扩频码。

Chaotic spreading sequences have good performance of auto-correlation, which make the ideal candidates of spreading sequences for asynchronous DS-CDMA systems. A discussion of the design of chaotic binary sequences based on fully stretching piecewise-linear maps is presented. Study results showed that the capacity of these sequences with alternating signs and exponentially decaying auto-correlation is bigger than that of Random sequence by 15.5%. The result of simulation of DS-CDMA using the designed sequences is in tandem with the theoretical analysis. It is shown that the designed sequence is suitable to be spreading sequence.