多跳CC-HARQ中继网络的频谱有效性跨层设计

在瑞利衰落信道中，为改善采用Chase合并混合自动重传请求( CC-HARQ)协议的多跳中继网络的频谱效率性能，考虑发送帧长和发送功率的跨层优化，研究了提升其频谱效率的跨层优化策略。不同于传统的中断概率分析，通过利用对数域线性阈值的平均误帧率估计方法，给出了多跳CC-HARQ协议频谱效率的精确表达式，在发送功率固定时设计了最优发送帧长策略，在发送帧长固定时设计了最优发送功率分配方案，进一步提出了跨层的联合优化方案。仿真结果验证了所设计优化方案在理论上的正确性和有效性，同时在仿真中可以观察到采用跨层的优化策略后，多跳 CC-HARQ中继网络的频谱效率获得了显著的提升，其中跨层的联合优化方案比传统的固定帧长等功率策略在频谱效率上提升了0.014 b/s·Hz-1。

Cross-layer design of spectral efficiency for multihop CC-HARQ relay networks

Over Rayleigh fading channels,the cross-layer optimum schemes to improve spectral efficiency ( SE ) for a multihop relay network with Chase-combining based hybrid automatic repeat request ( CC-HARQ) are investigated,where the cross-layer optimization of frame length and transmission power is con-sidered. Differing from the conventional analysis of outage probability, via utilizing a log-domain linear threshold method of average frame error rate estimation, an exact expression of SE for a multihop CC-HARQ protocol is presented,by fixing the transmission power or frame length to relatively design the opti-mal frame length scheme and optimal transmission power allocation method,then a cross-layer joint optimi-zation scheme is proposed. Simulation results validate the correctness and effectiveness of the analytical so-lutions,meanwhile,simulation shows that the performance of SE in multihop CC-HARQ relay networks is largely improved by adopting the proposed cross-layer optimization design,the cross-layer joint optimiza-tion scheme is able to achieve extra 0. 014 b/s·Hz-1 improvement of SE compared with the conventional scheme with fixed frame length and equal transmission power.