S-T线性耦合级联混沌扩频码及其性能分析

针对传统混沌映射迭代生成的时间序列复杂度低且序列取值范围受映射参数控制的问题,提出了一种基于S-T耦合级联混沌映射的扩频码生成算法。先通过引入耦合控制因子对满映射条件下的Sine映射和Tent映射进行线性耦合,在保持系统动力学结构完整性的前提下减弱了混沌参数取值对序列取值范围带来的影响,极大地增加了扩频码的地址空间。进一步,继续将耦合映射与Sine映射级联后作为扩频码生成器的驱动内核,通过级联的方式显著提升了映射迭代生成时间序列的复杂度,使得所生成的扩频码具有更强的伪随机特性。最后,基于Simulink平台搭建了加载S-T混沌扩频码的直序扩频系统,测试了在不同噪声环境下系统的误码率。实验结果表明,与基于原有传统映射的扩频系统相比较,基于线性耦合级联映射的扩频系统具有更低的误码率。

S-T Linear Coupled Cascade Chaos Spread Spectrum Code and Its Performance Analysis

For the problem that the low complexity of time series generated by traditional chaos mapping iteration is low and the range of sequence values is controlled by mapping parameters,a spread spectrum code generation algorithm based on Sine-Tent(S-T) coupled cascade chaos mapping is proposed.Firstly,the control factor is introduced to couple full Sine mapping and Tent mapping linearly on the premise of maintaining the integrity of the system dynamics structure,which eliminates the influence of parameter value on the range of sequence value,and greatly increases the address space of spreading code.Further,the algorithm continues to concatenate the coupled mapping and Sine mapping as the driving core of the spread spectrum generator.Finally,based on Simulink platform,a direct sequence spread spectrum system loaded with S-T chaos spreading code is built,and the bit error rate(BER) of the system in different noise environments is tested.The experimental results show that spread spectrum system loaded with the new mapping has lower BER than the one loaded with the traditional mapping spread spectrum system.