一种基于预编码的CPM正交扩频系统

针对传统CPM正交扩频系统实现复杂度高的问题，提出了一种基于预编码的CPM正交扩频系统。利用所提的预编码和可变星座映射技术，保证了CPM扩频信号的正交性；接收端采用码片校正技术，同步实现CPM解调和解扩，降低传统CPM扩频系统分步实现的复杂度。理论分析和仿真结果均表明，在AWGN和Rayleigh衰落信道下系统具有良好的误比特率性能。最后针对超短波通信进行应用设计和测试评估，结果表明，本系统优于美军SINCGARS系统约6dB。

Pre encoded CPM orthogonal spread spectrum system

To decrease the implementation complexity of the traditional continuous phase modulation (CPM) orthogonal spread spectrum system, a pre encoded CPM orthogonal spread spectrum system was proposed in this paper. Pre encoding technology and variable constellation mapping were introduced to guarantee the orthogonality of the CPM spread spectrum signal. In the receiver, chip revision was adopted to realize CPM and orthogonal demodulation simultaneously instead of the conventional separate demodulation, and the implementation complexity was also decreased. Both theoretical analysis and simulation results show that the proposed system has favorable BER performances in AWGN and Rayleigh fading channels. Finally, the application design was executed for VHF communication. It is shown that the proposed system outperforms SINCGARS system about 6 dB.