一种减小非授权频段HARQ进程时延的方案

针对利用非授权频段发送上行或者下行数据时某些HARQ进程总是在重传时刻没有占用到信道资源而导致时延过大的问题，提出了一种基于HARQ进程优先级分配信道资源的上下行重传方案。根据每个HARQ进程错过传输的次数和时延进行优先级判定，在竞争到信道使用权后按照优先级分配资源，使得各个HARQ进程以一种较为公平的方式使用有限的信道资源。在LTE系统仿真平台上建立非授权频段下的HARQ模型，并结合增量冗余（IR）和Chase合并技术进行性能验证。仿真结果表明所提方案的上下行HARQ进程平均时延有明显的降低，系统平均吞吐量得到一定程度的改善。

Scheme of reducing HARQ process latency in unlicensed spectrum

Concerning the excessive latency of some Hybrid Automatic Repeat reQuest(HARQ) processes resulting from the failure to occupy the channel resource at the transmission moment when Long Term Evolution(LTE) system is working in the unlicensed spectrum, a program to distribute the channel resource based on priority of different HARQ processes was proposed. Every HARQ process will be sequenced according to the times of missing transmission and latency value to occupy the channel after getting the right to use it so that the limited channel resource can be used by different HARQ processes in a fair way. HARQ retransmissions model combined with Incremental Redundancy(IR) and chase combining technology was established on the LTE system simulation platform to verify the performance. Simulation result shows that the average throughput increases significantly and the average HARQ process delay reduces sharply.