Resource Sharing Scheme for Device-to-Device Communication Underlaying Cellular Networks

Device-to-device (D2D) communication is deemed as a promising technology to improve the spectrum efficiency of the cellular systems. In this paper, we study a resource sharing scheme for the D2D communication underlaying cellular networks, where multiple D2D pairs can share subchannels with multiple cellular users (CUs). Our optimization task is to maximize the sum rate of D2D pairs while satisfying the rate requirements of all CUs. The formulated problem falls naturally into a mixed integer programming form that is intractable. We first develop a subchannel sharing protocol, by which we can determine whether or not a subchannel can be reused by two D2D pairs. Then, we prove that the problem can be well approximated by ignoring the mutual interference among the D2D pairs that share the same subchannels without deteriorating the performance of both the CUs and the D2D pairs. Based on the analysis results, we propose an efficient subchannel allocation scheme by employing a simple greedy strategy, as well as a power distribution algorithm that can work out almost the optimal solution to the original problem. Numerical results show that our proposal can significantly increase spectrum efficiency of the cellular system. Furthermore, our proposed subchannel sharing protocol is effective and efficient for practical communication scenarios.