Research On Relay Techniques Based On LTE-Advanced Systems

Relay Technology is one of the key technologies in LTE- Advanced, which can increase the system coverage, improve the link performance. Distributed Relay Assisted communication is an important technology that can meet the QoS requirement of terminal users. The main purpose of Relay Assisted communication can be summarized as extending the user coverage and increasing the system capacity. The distributed virtual MIMO system relies on the close cooperation among the independent relay nodes which randomly located nodes in space, which inducing the relay selection problem. This thesis will focus on the relay selection problem.1) Summarize physical layer concept of the LTE-Advanced system.Then, detailed analysis of cooperative communication in both AF and DF relay method.2) Current research on the relay selection is based on certain criteria to meet the requirements of the node selected as relay node collaboration. Common choice is based on the average channel state information and the instantaneous channel state information. This paper analyzes the three basic relay selection strategy that based on the average channel state information, that is distance-based relay selection, path loss-based relay selection and the SINR-based relay selection. In the establishment of the cell simulation model, we analysis and comparison these three fixed relay selection strategy. For the relay selection that based on the instantaneous channel state information, analysis the two relay selection method strategy.3) most of the studies did not consider the impact of interference on the relay selection, but the actual communication, the interference is inevitable. When the relay has interference, proposed the relay selection method, and analyze the performance. When considering the impact of interference on the relay node,proposed the relay selection method, and analyze the performance.4) In the relay network, the opportunistic relay selection in a manner that can obtain better performance, and opportunistic relay selection strategy need to get the full channel information. when there are too many relay nodes, the actual operation is quite difficult. Here given a relay selection strategy, according to set the decision threshold by the relay node to decide whether to forward the data sent from the source.