Efficient Resource Allocation and Power Control for LTE-A D2D Communication With Pure D2D Model

To support the rising number of user equipments (UEs), LTE-A allows some UEs directly talking with each other to facilitate spectrum reuse, which is known as device-to-device (D2D) communication. Since D2D UEs (DUEs) consume resources and bring out interference, how to allocate resources and power is important. Existing studies seek to make more DUEs reuse resources of cellular UEs (CUEs, which are the UEs talking with the eNB) to increase throughput. However, it is inefficient for some CUEs (e.g., those near cell edge) to share resources with others due to high interference. Thus, a new sharing paradigm, called the pure D2D model, is proposed to allow DUEs sharing resources without involving CUEs for flexibility. This new model is helpful to IoT (Internet of Things) applications, where the overwhelming majority of devices are usually DUEs. The paper defines an optimization problem to maximize links supported in the network, and proposes a D2D resource allocation and power control (DRAPC) framework. By vertex coloring, DRAPC gives a preliminary grouping of UEs for resource allocation. Then, each group is carefully reformed by exchanging members and adding new ones, so as to increase signal quality and degree of resource sharing. Simulation results show that DRAPC not only improves network performance but also guarantees fairness among links.