System performance of two-way decode-and-forward relaying assisted D2D communication underlaying cellular networks

In this paper we investigate the achievable sum-rates of device-to-device (D2D) communication assisted by decode-and-forward (DF) relay node. Firstly we introduce the operation principles of three communication transmission modes which are named as classical cellular communication mode, direct D2D communication mode and two-way-DF-relayed D2D communication mode. Then we derive the corresponding expressions for the ergodic achievable sum-rates of each transmission mode. Based on these results, we then show that the D2D communication aided by DF relay node gains advantages over that of the classical strategy. Numerical results demonstrate that by applying two-way-DF-relayed D2D communication mode, the achievable sum-rate of the system achieves a remarkable enhancement.