Efficient Coding And Modulation Design In Satellite System

In the research of satellite mobile communication system, coding and modulation have important influence to the performance of the entire system. This paper analyzes the different combination schemes of Turbo codes/LDPC codes and APSK/CPM modulation, analyzes the performance and complexity of these combination schemes in Rician fading channel, and determines a group of efficient coding and modulation schemes applied to satellite communication system.This paper emphatically analyzes and studies the following contents:1. Based on the non-linear property of satellite channel, the APSK constellation is optimized to minimize the non-linear distortion caused by satellite transponder. According to the research of the performance and complexity of the system composed of Turbo codes/LDPC codes and APSK modulation in Rician fading channel, the appropriate code pattern of Turbo codes/LDPC codes is selected. By means of the comparison of the two different combination schemes, corresponding solution schemes are proposed, according to different application background such as synchronous satellite, low orbit satellite, high-speed communication, low-speed communication and etc.2. This thesis proposes an acquisition method of soft decision information in 16APSK modulation, which simplifies calculating complexity.3. We study the characteristics of CPM modulation, and focus on the modulation and demodulation principles of MSK which is the most widely used. Based on the performance and complexity of the system composed of Turbo codes/LDPC codes and MSK modulation in Rician fading channel, the appropriate code pattern of Turbo codes/LDPC codes is selected. By means of the comparison of the two different combination schemes, corresponding solution schemes are proposed according to different application background.The simulation results show that the combination scheme mentioned above can improve reliability and efficiency of the system, and is a very attractive technical solution for satellite mobile communication system.