Joint Relay Selection and Resource Allocation for D2D-enabled Cellular Communications

Device-to-device (D2D) communications allow direct transmissions between two proximate user equipments (UEs) under the control of base stations (BSs), which can improve local services and spectrum efficiency in cellular networks. In this paper, we propose an efficient resource allocation scheme and a low complexity relay selection strategy for D2D communications enabled cellular networks, where a D2D UE can act as a source as well as a potential relay for other UEs. Consider the selection cooperation (SC) rule which restricts relaying for a D2D transmitter to only one relay (i.e., another D2D transmitter) is imposed. First, we formulate the resource allocation problem for the cooperative D2D transmitters as a bargaining game. By solving the Nash bargaining solution (NBS) of the game, proportional fair (PF) rate allocation for the D2D communications can be achieved. Next, to implement the SC rule, a simple heuristic is proposed which is used to maintain the long-term priority fairness of relay selection for each D2D link. The proposed algorithm has a low computational complexity of O(N-2), where N is the number of cooperative D2D transmitters in a game. Simulation results demonstrate the system efficiency and fairness properties of the proposed scheme.