正交多用户CD-DCSK方案的设计及性能分析

为了进一步提升现有多用户混沌键控系统的信息传输速率和误码率(BER) 性能，该文提出一种正交多用户CD-DCSK(OMU-CD-DCSK)系统。该系统在差分混沌移位键控(DCSK)的基础上结合了相关延迟移位键控(CDSK)，每个时隙中利用正交的Walsh码序列可以传输N bit的多用户信息，然后通过正交调制技术进一步提升传输速率。在接收端，采用滑动平均滤波器降低噪声方差，改善误码性能，之后进行相关解调即可恢复多用户信息比特。推导了多径瑞利衰落信道下系统的理论BER，并通过蒙特卡罗仿真实验进行了验证。此外，还定义了系统的综合效用，用于评估混沌系统的综合性能。与其他混沌键控系统相比，OMU-CD-DCSK的综合性能有明显优势，因此具有较好的实用价值。

Design and Performance Analysis of Orthogonal Multi-User CD-DCSK Scheme

To improve further the information transmission rate and Bit Error Rate (BER) performance of existing multi-user chaos keying systems, an Orthogonal Multi-User Correlation Delay Differential Chaos Shift Keying (OMU-CD-DCSK) system is proposed in this paper. The system is based on DCSK combined with Correlation Delay Shift Keying (CDSK), which can transmit N bit multi-user information in each time slot using orthogonal Walsh code sequence, and then increase further the transmission rate by quadrature modulation technique. At the receiver, a moving average filter is used to reduce the noise variance and improve the BER performance, followed by correlation demodulation to recover the multi-user information bits. The theoretical BER of the system under multipath Rayleigh fading channel is derived, and verified by Monte Carlo simulation experiments. Furthermore, the integrated utility of the system is defined for evaluating the integrated performance of the chaotic system. Compare with other chaotic keying systems, the integrated performance of OMU-CD-DCSK has obvious advantages. Therefore, it is of great value in application.