正交多载波降噪差分混沌键控通信系统

为解决多载波差分混沌移位键控(MC-DCSK)系统传输速率低和误码性能差的缺点，该文提出一种正交多载波降噪差分混沌移位键控(QMC-NR-DCSK)系统。在发送端，预定义载波用于发送参考信号，剩余M-1个不同中心频率的载波及其经正交调制技术后得到的频率相同但相位正交的载波都用于传输信息信号，此外，通过进一步引入Hilbert变换，将系统的频带利用率和传输速率提升为MC-DCSK系统的4倍。在接收端引入滑动平均滤波器的降噪操作降低了噪声的方差，从而改善了系统误码性能。推导了QMC-NR-DCSK系统在加性高斯白噪声(AWGN)信道和多径瑞利衰落(RFC)信道下的比特误码率公式并进行了仿真。仿真结果和理论分析表明：QMC-NR-DCSK系统能有效提升传输速率、带宽效率和误码性能，为该系统应用于多载波无线通信提供理论参考。

Quadrature Multicarrier Noise Reduction Differential Chaos Shift Keying System

The major drawbacks of MultiCarrier Differential Chaos Shift Keying (MC-DCSK) system are relating to low data rate and poor bit error performance. Therefore a Quadrature MultiCarrier Noise Reduction Differential Chaos Shift Keying (QMC-NR-DCSK) system is proposed to improve the performances of MC-DCSK system. At the transmitter, reference signal is transmitted on the predefined carrier. While the remaining M-1 carriers and the carriers with orthogonal phase at the same frequency are all used to transmit information signals by using Quadrature Modulation technology, and the data-rate to bandwidth ratio and transmission rate of which are four times higher than that of MC-DCSK system by further introducing Hilbert transformation. The noise reduction operation of the moving average filter is introduced to reduce the variance of noise at the receiver, thereby improving the bit error performance of the QMC-NR-DCSK system. The bit error rate formula and simulations of QMC-NR-DCSK system under Additive White Gaussian Noise (AWGN) channel and multi-path Rayleigh Fading Channel (RFC) are carried out respectively. The results show that QMC-NR-DCSK system can effectively improve the transmission rate, data-rate to bandwidth ratio and bit error performance, which provides a theoretical reference for the application of the multicarrier communication systems.