慢衰落信道下并行HARQ系统的速率自适应算法

Rate Adaptation Algorithm for Parallel HARQ System over Slow Fading Channel

为提升慢衰落信道下多路并行混合自动重传请求(HARQ)系统的吞吐率性能,提出一种基于实时信道状态信息估计的速率自适应算法。设计适用于多次重传的速率自适应策略,推导系统吞吐率与速率选择的关系,并使用动态规划方法求解最优速率配置。瑞利衰落信道下的仿真结果表明,相比使用非实时信道状态信息的HARQ速率自适应算法,实时信道状态信息估计算法能够有效提升系统吞吐率性能,低信噪比情况下提升效果更明显。

To improve the throughput performance of the multiple parallel Hybrid Automatic Repeat Request(HARQ)systems over a slow fading channel,this paper proposes a rate adaption algorithm based on estimation of real-time Channel State Information(CSI). A rate adaption strategy for multiple retransmissions is designed. The relationship between system throughput and rate selection is deduced theoretically,and the dynamic programming method is used to obtain the optimal rate configuration.Simulation results obtained in a Rayleigh-fading channel show that compared to the HARQ rate adaption algorithm with outdated CSI,the HARQ rate adaption algorithm with estimation of real-time CSI can improve the system throughput effectively. Especially in the case of low Signal-to-Noise Ratio(SNR),the improvement effect is more obvious.