自适应混合自动重传请求(hybrid automatic repeat request，HARQ)系统的性能与每次传输中的调制与编码方案(modulation and coding scheme，MCS)、发送功率选择密切相关，通过优化重传时的MCS及发送功率可以提升HARQ系统的吞吐率并降低能耗。由于不同MCS传输合并后的译码性能没有闭式解，这导致自适应HARQ优化问题不易解决。首先基于译码的判决域半径给出了一种HARQ合并后译码错误率的近似公式，进而提出了多种能权衡吞吐率和能耗性能的自适应HARQ优化策略。仿真结果验证了所提错误率估计方法的可靠性以及所提自适应HARQ的性能。与传统HARQ方案相比，所提方案能同时提高吞吐率、降低能耗，实现更好的吞吐率与能耗的性能折中。
Adaptive HARQ based on retransmission error rate estimation
The performance of adaptive hybrid automatic repeat request(HARQ)systems is closely related to the modulation and coding scheme(MCS)and transmit power selected in each transmission.By optimizing the MCS and transmit power of retransmissions,the throughput of the HARQ system can be improved and the energy consumption can be reduced.Since there is no closed-form solution to the decoding performance after combining transmissions using different MCSs,the optimization of adaptive HARQ is limited.An approximate formula for the code error rate after HARQ combining,based on the radius of the decoding decision region is given firstly,and then several novel optimization strategies are proposed for adaptive HARQ that can trade off throughput and energy consumption.Simulation results verify the correctness of the derived formula and the performance of the proposed methods.Compared with the conventional HARQ,the proposed methods can increase the throughput while simultaneously reducing the energy consumption,thus achieving a better throughput-energy consumption tradeoff.
adaptive hybrid automatic repeat request(HARQ)modulation and coding scheme(MCS)throughputenergy consumptionradius of decision region
万方数据
维普
