面向光通信的物理帧格式设计与同步算法研究
Exploring Physical Frame Format Design and Synchronization Algorithm for Optical Communication

空间光通信具有保密性好，信息容量大，抗干扰能力强等优点，是现代通信系统研究的热点之一。脉冲位置调制（pulse position modulation，PPM）是空间光通信系统中一种性能优良的调制方式。针对空间光通信系统中信息传输速率低，设计了一种改进的"空-空-零"的物理帧格式，以提高空间光通信系统的传输速率。针对实际空间激光数字接收机，深入开展了帧同步算法设计研究。结合设计的物理帧格式，重点研究了帧同步算法的设计，为了应对噪声等参数的变化，提出自适应相关阈值设置；考虑到工程实现，提出了一种相关滤波简化实现方法等。最后，基于FPGA完成了接收机原型系统设计，经Matlab仿真、在线仿真以及实际测试表明了该设计方案的正确性和可靠性。
Space optical communication has been a hot topic in modern communication system research, because it has many advantages, such as good secrecy, large information capacity, strong anti-interference ability, and so on. Pulse position modulation (PPM) is an excellent modulation method. In view of the low rate of information transmission by a space optical communication system, an improved "empty-empty-zero" physical frame format is designed to improve its transmission rate. In view of the actual space laser digital receiver, the frame synchronization algorithm is designed in this paper. Based on the physical frame format, this paper focuses on the design of frame synchronization algorithm. In order to deal with the change of noise and other parameters, an adaptive threshold setting is proposed. Considering the engineering implementation, a simplified correlation filtering implementation method is proposed. Finally, we designed the reception prototype system based on FPGA. The Matlab simulation, online simulation and experimental verification prove that the proposed method is correct and reliable