Research On Relay HARQ Technology Based On LTE-A System

In order to achieve the smooth evolution of LTE system, LTE-Advanced system is considered as an important step by the 3GPP organization. Release 10 introduced the support of Relay. It is possible to improve the system coverage based on the wireless backhaul of relay. It greatly satisfied the requirements of the data rates and the average throughput in the cell edge. The Hybrid Automatic Repeat Request technology can ensure the system's reliability; make up the losses caused by the time varying of wireless channel and the multipath fading in the signal transmission.Some related research and performance evaluation of relay HARQ mechanism of LTE-A system has carried on in this paper. Analyzed the HARQ timing between backhaul link and access link, discussed the possible conflict of them, and then proposed the possible solution. Besides, this paper did deeply research on relay cooperation retransmission, improved the original method. Finally verified the validity of the new method based on the system simulation platform.The main works are as follows:(1) Studied the resource allocation between backhaul link and access link,compared the advantages and disadvantages of FDM?TDM and FDM+TDM mode,what's more, analyzed the different modes may bring the impact to the system.(2) Analyzed the conflict of subframe configuration between backhaul link and access link. And with the further study of HARQ timing, adjust the way of subframe configuration, taking the configuration 3 as an example. Minimize the impact on the access link on the basis of the normal transmission of backhaul link, ensure the backward compatibility of the system.(3) Proposed an improved way of relay coordination on the basis of the two ways of retransmission controlled by terminal and relay. Then proved the scheme is feasible and it can balance the time delay and system bit error rate better.