反馈时延对短波跨层通信吞吐率影响

为实现和提高短波通信中跨层设计的性能，针对短波跨层通信系统中反馈延时不能忽略的问题，研究了反馈延时对系统吞吐率所产生的影响。首先研究不同系统中反馈延时由于增大总的传输时间，带来吞吐率的下降，认为固定发送时间比固定数据帧结构具有更大的系统吞吐率性能。其次分析反馈延时对接收端信噪比估计的有效性影响，带来传输模式选择上的误差，影响系统的吞吐率性能。最后分析得到在反馈信噪比情况下，根据反馈信噪比误比特性能计算的信噪比判决区间与根据理想信噪比误比特率性能计算的信噪比区间相比，会带来系统吞吐率的提升。

Feedback Delay Impact the Throughput of the Cross-Layer Designfor HF Communication

In order to realise and improve the performance of cross-layer design in HF communication, feedback delay problem was studied which could not be ignored. The influence of the feedback delay on the throughput was mainly researched. First the feedback delay would reduce the throughput by increasing the total transmission time. And the conclusion of fixed frame transmission delay could get higher throughput performance than fixed frame structure was found out. Second the feedback delay would bring error to the SNR estimate in receiver, which would degade the throughput. What was more, under the situation of SNR estimation, the SNR selection range calculated by the estimated SNR could have a higher performance compared with which was calculated by the ideal SNR..