Research On Device-to-Device Communication Technologies Underlaying LTE Networks

To satisfy the increasing demand for higher data rates, Device-to-Device (D2D) communicationas an underlay to cellular networks has been proposed. It allows user equipments (UEs) in closeproximity to communicate directly without through the evolved NodeB (eNB). These UEs can sharethe same resources with cellular users to improve resource utilization. But the resource sharing willbring interference to cellular users, thus interference management is one of the most critical issuesfor D2D communications underlaying cellular networks.D2D communications underlaying LTE networks is considered in this paper. First of all, LTEnetwork architecture and radio resource management are outlined. Then the paper introduces thekey technologies of D2D communications and focuses on various researches of interferencemanagement, including resource allocation and power control. Furthermore, a D2D system-levelsimulation platform is described. At last, two interference management shemes are proposed, toprotect the fairness of cellular networks with proportional fair (PF) algorithm.One of the shemes has three steps. It first performs admission control to guarantee thequality-of-service (QoS) requirements for both D2D users and regular cellular users (CUs), and thenallocates powers for each admissible D2D pair and its potential CU partners. Next, a minimumweight bipartite matching based scheme is developed to select a suitable CU partner for eachadmissible D2D pair to minimize the overall variation of cellular network schedule metric.Numerical results show that the proposed scheme can significantly improve the fainess andthroughput of the cellular network.Another solution with a new scheme is proposed in order to recover the fairness betweencellular users. In this scheme, D2D users are firstly scheduled, and then cellular users are scheduledknowing the interference from D2D users. Power control is used for enhancing the overallthroughput. Simulation results show that, compared with the common scheme, the proposed methodcan achieve better fairness by25%.