Study On Relay Selection In Cellular Multihop Transmission Scenario

With the rapid development of communication industry, the innovation of communication equipment, and the explosive increase of mobile Internet business data, people are enjoying convenience of communication technology, however, the data capacity and transmission rate put forward higher requirements against the existing mobile communication network. The introduction of relay technique can effectively improve the performance of the network system, and thus it has received extensive attention from researchers. Moreover, as a key technique to ensure implementation of the relay technique, relay selection technique has become a research hotspot.This paper conducts the research on relay selection scheme in multi-hop relay network on the basis of extension of the relay selection techniques and the summary and analysis on the multi-hop technology, especially for relay communication and D2D communication techniques. Then, the article respectively designs multi-hop relay selection schemes aiming at two different scenarios in cellular multi-hop transmission network.In order to improve throughput of the wide-area multi-hop transmission network, and guarantee to effectively reduce the BER in the process of data transmission, Alamouti coding based relay selection strategies for wireless multi-hop network is proposed. According to different number of the sending node and the receiving node in each hop in the whole transmission link, the relay selection method is divided into three kinds of situation. Combined with special consideration of known destination node in last hop, relay selection scheme proposed consist of the relay selection in first hop, in middle hops and in last two hops. Specific relay selection in each hop is based on the maximum channel capacity or the conjoint analysis of channel capacity in last two hops. The simulation results show that, Alamouti coding based relay selection strategies for wireless multi-hop network can improve the network throughput and reduce the BER in transmission effectively.For the transmission scenario of the D2D multi-hop relay network coexisting with cellular network, assuming that the cellular base station is aware of the channel state information between users within the cell and between user and base station, the CSI based D2D multi-hop relay selection scheme is proposed. Under the premise of reuse in the cellular uplink time slot resources, according to the effective interference control of cellular base station and under the guarantee of the DF relay protocol, the transmission power of the nodes deployed in D2D multi-hop relay network is limited. At last, according to the optimal channel quality of in each hop and the conjoint judgement of channel quality in last two hops, relay selection is conducted in D2D multi-hop relay network. The simulation results show that, the CSI based D2D multi-hop relay selection scheme can effectively reduce the power consumption of the multi-hop transmission, and the interference with cellular base station in transmission process.