码复用差分混沌键控性能分析与同步算法

码复用差分混沌键控(code-shifted differential chaos shift keying,CS-DCSK)是一种具有优良抗多径衰落能力的非相干混沌调制技术,虽然非相干混沌调制技术不需要在接收端恢复混沌载波,但准确的符号同步是保证系统性能的前提.介绍了CS-DCSK系统的结构模型,包括发射机和接收机原理以及CS-DCSK独特的信号帧结构,然后采用高斯近似法(Gaussian approximation,GA)分析了高斯信道和Nakagami-m衰落信道下符号同步误差对CS-DC-SK误码性能的影响,最后提出一种符号同步算法,该算法通过发送训练序列首先完成帧间的粗同步,在粗同步的基础上完成帧内的细同步.仿真结果表明,在高斯信道和Nakagami-m衰落信道下,仿真结果与理论分析基本一致.通过与理想同步情况下的误码率性能比较,提出的同步算法存在2 dB左右的性能损失.

Performance analysis and synchronization algorithm for CS-DCSK system

Code-shifted differential chaos shift keying (CS-DCSK) is a non-coherent chaotic demodulation technology that has low complexity and good performance of anti-multipath fading channels. It does not require recover chaos carrier at receiver, but the accurate symbol synchronization is the prerequisite to guarantee the performance of the system. This paper firstly introduces the structure of CS-DCSK system including transmitter, receiver and the unique signal frames of CS-DC-SK. Then it investigates BER performance of CS-DCSK with synchronization error in AWGN and Nakagami-m channel respectively using gaussian approximation (GA) method. At last, an efficient synchronization algorithm is proposed for CS-DCSK. In the algorithm, firstly we use training symbols to complete inter-frame coarse timing, then to finish fine timing on the basis of the coarse timing. Simulation results show that the simulation and the theoretical analysis are basically consistent with both AWGN and Nakagami-m channels. Compared with the perfect synchronization, the BER performance of the proposed synchronization algorithm has about 2dB performance loss.