基于星上自适应FEC的卫星数据分发

Satellite Data Distribution Based on Adaptive Packet-level FEC

为了解决卫星数据分发系统中雨衰对下行链路的异构性影响，建立了基于再生转发器和多波束技术的卫星数据分发系统简化模型，提出了采用星上自适应分组级FEC（ForwardErrorContr01）的下行链路差错控制方法，针对下行链路的降雨等级自适应选择纠错码率，在不占用上行共享链路的情况下，实现对下行链路差错控制的动态调整，给出了采用RSE码的星上自适应FEC的算法公式，通过MATAB软件和端到端的FEC技术进行了仿真比较分析，结果表明，当下行链路降雨率小于50％时，网络吞吐率可提高12％～25％。该策略可以为多波束宽带卫星数据分发系统的设计提供参考。

To eliminate the influence of rain attenuation on satellite downlink heterogeneity in satellite data distribution system, a satellite data distribution system model which adopts satellite regenerator and muhi- beam technology is built, and the downlink error control method based on the technology of adaptive packet -level FEC is presented, which changes the correcting code rate according to the rain grade, and realizes the dynamic adjustment of downlink error control with the uplink not being occupied, the arithmetic expres- sions of the satellite adaptive forward error control（FEC） which adopts RSE code are deduced. Finally, the method is compared with the end to end FEC technology by simulating in MATLAB software and the result shows that the scheme can improve the network throughput efficiency by 12% ~ 15% when the downlink rain rate is below 50%. Therefore, the method can be consulted for design of multi-beam satellite data dis- tribution system.