5G系统中无线链路控制层ARQ机制的研究及算法优化

Research and algorithm optimization of ARQ mechanism of radio link control layer in 5G system

针对现有ARQ机制在5G系统中实用性低以及流程复杂的缺点,为克服重传机制传输速率低、时延严重以及备份缓存占用时间久的问题,基于无线信道质量提出一种改进型重传方案。首先基于无线信道质量设定信道门限系数,AM发送实体根据调度结果组包,设置轮询后发送数据至对等实体;然后通过实时监控信道系数的幅度与门限系数做比较,自适应选择对等实体的状态报告或HARQ反馈应答;最后解析状态报告和HARQ应答后重发或进入下一帧传输。仿真结果表明,相较于传统ARQ设计方案,此方案能实现无线链路控制层的快速重传,降低传输时延,增加用户数据吞吐量。

In view of the shortcomings of poor practicability and complex process in the existing ARQ(automatic repeat request)mechanism in 5G system,an improved retransmission scheme is proposed for wireless channel quality to solve the problems of the low transmission rate,serious delay and long time occupation taken by backup buffer in the retransmission mechanism.The channel threshold coefficients are set based on wireless channel quality.The AM sending entity is used to assemble data packets according to the scheduling results,set up polling conditions,and then send the data to the peer entity.And then,by comparing the real⁃time monitoring amplitude of the channel coefficient with the threshold coefficient,the status report or HARQ(hybrid automatic repeat request)feedback response of the peer entity is adaptively selected.The status report or HARQ response is analyzed for retransmission or entering the next frame transmission.The simulation results show that,in comparison with the traditional ARQ design scheme,this scheme can achieve fast retransmission of the RLC(radio link control)layer,reduce transmission delay and increase user data throughput.