基于LDPC码和喷泉码的卫星动中通链路拥塞控制研究

项目名称： 基于LDPC码和喷泉码的卫星动中通链路拥塞控制研究

项目编号： No.61501469

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 无线电电子学、电信技术

项目作者： 戴精科

作者单位： 中国人民解放军火箭军工程大学

项目金额： 21万元

中文摘要： 以卫星动中通为背景，针对信号易被遮挡而产生阴影效应的问题，本项目拟设计鲁棒性强的前向纠错编码方案，重点研究阴影遮挡信道中的LDPC码性能分析与度分布设计；并解决在长时阴影条件下，因一帧错误比特过多而无法恢复数据的问题。理论上：①基于密度进化理论，分析不同信道状态的软信息在译码器中的演进，设计混合信道密度进化算法；②对LDPC码在阴影信道中的理论性能进行分析，并对其节点度分布进行优化；③为降低长时阴影下的误帧率，研究抗长时阴影的数字喷泉码方案。工程上：验证在实际阴影条件下，本项目所提前向纠错方案的有效性；进一步研究前向纠错与自动请求重传技术的组合，提高系统的抗阴影能力。本项目提出的链路拥塞控制方法不仅可以有效缓解阴影效应对动中通系统的影响，还能提高卫星通信系统在恶劣天气条件下的传输可靠性。项目研究成果拓展了LDPC码性能分析方法，并为动中通系统对抗阴影效应提供了有效的技术途径。

中文关键词： 卫星移动通信；宽带卫星通信

英文摘要： Under the background of the satellite communications on the move (SOTM) and aiming at the shadow problem caused by signal blockage, the robust forward error correction coding scheme will be proposed accordingly. The research focuses on the performance analysis and degree distribution of LDPC code under blockage channel. Furthermore, the data can not be recovered under long time shadow because of overmuch error bits in one frame, the problem of which is also considered. In theory, ① based on the density evolution theory, the gradual progress of soft information in decoder is analyzed under various channel states. ② the theoretical performance of LDPC code under shadow channel is investigated and the degree distribution is optimized. ③ the digital fountain code scheme is proposed to counteract long time shadow and decrease frame error rate. In engineering, the effectiveness of proposed forward error correction scheme is verified under the practical shadow condition. The proposed link blockage mitigation method based on LDPC and fountain code not only decreases the effect of shadow to the SOTM system, but also improves the transmission reliability of satellite system under severe weather. The project achievement will extend the performance analysis methods of LDPC code, and provide a new technical approach to combat shadow effect for SOTM system.

英文关键词： Satellite Mobile Communication;Satellite Broadband Communication