Interference management for D2D communications in heterogeneous cellular networks

Abstract

Device-to-device (D2D) communications in cellular networks enable user equipments (UEs) to directly communicate with each other without the relay of base stations (BSs). They can improve network performance, while they also complicate interference management (IM). In this paper, the IM issue is studied for the D2D communications underlaying heterogeneous networks consisting of macro and small cells. Investigation is first made into D2D performance for UEs in different communication modes (D2D mode and device-to-cell modes). Then, a D2D feasible set is defined and derived which gives a region to allow D2D links to share network resource; and a feasible set scheme is proposed to manage the interference among communication links in order for the cellular links and D2D links to satisfy quality of service (QoS) requirements. After this, the optimal deployment of small cells is studied and an optimal deployment scheme is found that maximizes the transmission density while the QoS of links in different communication modes can be guaranteed. The analytical results are obtained and the calculations show that the proposed interference management schemes can effectively mitigate interference among cellular links and D2D links; and all the links (macro cell link, small cell link and D2D link) can satisfy the QoS requirement when they are sharing the resources. Compared to the neighbor based scheme, the proposed scheme can reduce the average outage probability up to 92%. In addition, the proposed deployment scheme can maximize the transmission capacity with guaranteed link QoSs.