基于CQI辅助的协作HARQ实现策略*

传统的中继HARQ通信方案中,目的端会对源端和中继端首次传输的数据进行最大比合并译码,但是Turbo译码是一个非常繁杂的迭代译码,会消耗用户大量的时间和功率,当目的端在译码失败请求重传时,这一次译码将直接导致系统的时延增加。针对这一问题,提出了在传统中继HARQ通信系统中引入CQI辅助译码的HARQ通信策略,并在此基础上给出了门限自适应设定方法,解决了CQI辅助中继HARQ通信方案中难以在瑞利衰落信道下准确设定辅助门限的问题。该策略在译码前通过CQI信息对数据包的好坏作出预判断,从而确定下一步是直接译码数据包还是跳过译码环节直接发送NACK请求重传,进而减少系统时延。通过理论和仿真分析,比较了CQI辅助中继HARQ通信方案的时延和误包率等系统性能指标,验证了CQI辅助中继HARQ通信方案有着更好的时延性能。

Cooperative HARQ implementation strategy based on CQI

In traditional cooperative HARQ communication system,signal from source and relay would be maximal ratio combined by destination.However,turbo decoding that consumes a large number of UE’s time and power is very complicated.The decoding will directly cause delay of the system when destination requires retransmission after decoding fails.To solve this problem,this paper introduced the channel quality information(CQI) to assist the HARQ decoding,and proposed an auxiliary threshold adaptive set method.It judged the quality of packet before decoding by the scheme,in order to determine whether directly decode the packet or skip the decoding and feedback NACK,for reducing transfer delay.At the same time,solving the difficulty of accurately setting the auxiliary channel threshold in the CQI auxiliary relay HARQ scheme.At last,analyzed the performance of the CQI auxiliary relay HARQ scheme such as delay,package error rate and so on,it is verified that the CQI auxiliary relay HARQ scheme has a better delay performance.