Research On Relay Selection And Resource Allocation Algorithm Based On D2D Communication

Device-to-Device(D2D)technology can improve spectrum utilization and reduce the burden on base stations by multiplexing channel resources of cellular communication users.When some users who are greatly affected by channel fading cannot communicate normally,the relay node can assist in information transmission.The addition of relay nodes will make the interference more complicated.Therefore,selecting the appropriate relay node and allocating reasonable channel resources can effectively expand the network coverage and optimize system performance.In order to solve the problems of poor communication between users at the cell edge and complex interference in D2 D relay systems,this thesis studies relay selection and resource allocation algorithms that support relay-assisted communication technology based on the characteristics of D2 D communication.The main research contents and work results are as follows:1.According to the main characteristics of D2 D relay communication technology,a single-cell system model of relay-assisted cellular communication is established.This thesis analyzes the interference situation of a D2 D user multiplexing a cellular user's uplink resources,and converts the relay selection and resource allocation problems into mathematical models for optimizing link capacity and scheduling priority,respectively.2.Aiming at the problem of poor communication quality of users at the cell edge,a relay selection algorithm combining the principle of auction is proposed.The algorithm first analyzes the triggering conditions of the relay,and finds idle devices for each edge user as an alternative relay set;then calculates the transmission rate of each node in the set in the communication link,and find the solution that maximizes the transmission rate;finally,considering the case where multiple edge users choose the same node,the auction principle of edge user bids is adopted for relay auctions.Simulation results show that the proposed algorithm effectively improves the throughput of edge users,and ensures the probability of system outage.3.Aiming at the problem of complicated interference in D2 D relay system,a resource allocation algorithm based on proportional fairness is proposed.The algorithm first determines the feasible range of transmit power through linear programming;then sets the service rate satisfaction degree function in the first slot,designs a weight factor that considers the fairness of the scheduling of cellular users and D2 D users,and determines the multiplexing combination according to the weight factor;finally,in the second time slot,resources are allocated with the goal of maximizing system throughput.Simulation results show that the proposed algorithm effectively improves the throughput of the system and improves the fairness of resource allocation.