Opportunistic resource scheduling for D2D communication in OFDMA networks

In this paper, we study a resource scheduling problem for D2D communication in OFDMA cellular networks. In addition to opportunistically scheduling power and subchannels to users as in the conventional OFDMA network, we also consider two distinguishing features for D2D communication to fully utilize the advantages of D2D communication: transmission mode selection and channel reuse. First, we allow each D2D user to opportunistically select its transmission mode between direct one-hop transmission and indirect two-hop transmission through the BS. Second, we allow channel reuse within a cell such that users can share the same subchannel within a cell. We formulate an optimization problem that aims at maximizing the average weighted sum-rate of users, while satisfying the QoS requirement of each user. Our problem is a non-convex and coupled optimization problem, which is inherently difficult to solve, especially due to channel reuse within a cell. Despite of it, we develop an optimal opportunistic resource scheduling algorithm that solves the problem. In addition, we also propose two simple heuristic algorithms to reduce the computational complexity of the optimal algorithm. Through simulations, we show our opportunistic scheduling algorithms achieve a high performance with appropriately utilizing the advantages of D2D communication.