Research On Relay Selection Strategy For Device-to-device Communication System

D2D(Device-to-Device) technology enable terminals communication directly. It eases the burden of cellular network and enlarges the capacity of communication system. By introducing relay technology into D2 D communication system, the utilization rate of resource increased and the reliability of the system enhanced.Single relay selection strategy for D2 D communication system is studied in this paper first. This thesis analysis the signal retransmission modes of D2 D relay, and deduce the system performance index of AF mode and DF mode. This thesis does its research on relay selection strategy by the parameters of SINR, distance and energy consumption. Comprehensive relay selection strategy is researched for multiple scenarios. This strategy can obtain network’s optimal performance by automatic correcting parameters. The simulation result shows comprehensive relay selection strategy behaves well in different occasions by a low BER and a long service life.N-hop relay selection strategy for D2 D communication system is studied in this paper second. This thesis takes the interference between terminals into consideration when discussing the performance of the system, and derives the formula of SINR and channel capacity. N-hop relay selection strategy based on greedy algorithm and de-hole algorithm is research in this thesis. It increases utilization rate of idle terminals by N-hop technology and solves the problem of unreachable terminals by de-hole algorithm. The simulation results show that the N-hop relay selection strategy can increase the utilization rate of system, and enhance the reliability of the system.Multicast relay selection strategy for D2 D communication system is studied in this paper at last. This thesis does its research on D2 D virtual MIMO technology. It derives the formula of SINR and channel capacity by analyzing the interference between terminals and the MIMO technology. Intra-cluster multicast relay cooperative algorithm and virtual MIMO algorithm are research in this thesis. It decreases the resource cost of system and improve the performance of system. The simulation results shows, the algorithm can save resources of system and improver the data rates of network.