自适应HEC在卫星移动通信中的应用研究

卫星陆地移动通信LMS信道电波传播由于阴影效应引起的慢衰落特性具有高动态性。当采用功率控制时。长的回路时延容易产生功率控制间隙。从而在状态过渡时引起大量的突发性差错．为了解决这个问题。先纠错后检错再重发的传统混合纠错方法。当存在大量突发性差错时。会带来时延增大和吞吐率的下降。本文提出一种自适应混合纠错(HEC)方案。通过帧的平均可靠度和一个指定的门限值进行比较来自适应选择FEC和ARQ，这个方案能达成高的吞吐率，非常适合于对传输有严格时延要求和合适误码率要求的卫星话音和图像通信．

Application of Adaptive HEC in Satellite Mobile Communication

Since there exists high dynamics in the slow fades of LMS (land mobile satellite)propagation due to the shadow of environment When power control is employed, the long loop lag induces power control gaps during channel state transition, which results in long bursterrors To combat it the conventional method will result in long delay and low throughout when long bursterrors exist Aadaptive hybrid error correction scheme is proposed in this paper FEC and ARQ is adaptive according to the comparison between the mean reliability of the frame (LLR l )and a appointed threshold The scheme can achieve high throughout, so it is very fit for satellite voice and image communication that needs high delay demand and adequate BER