Mobility-Aware Mode Selection, Relay Selection, and Resource Allocation for D2D Communication

Mobility management and radio resource management are critical aspects of device-to-device (D2D) communication due to the coexistence of cellular user equipments (CUEs) and D2D user equipments (DUEs) operating within the same spectrum. Therefore, in this paper, we target a problem of D2D communication for mobile users and we address it via joint selection of communication mode (i.e., cellular mode, relay mode, D2D mode), selection of relay, and allocation of resources to maximize the sum rate of D2D pairs while ensuring quality of service for all CUEs. As the formulated problem is a binary integer nonlinear programming problem, which is of very high complexity, we first develop a preliminary greedy approach virtually pre-selecting only mode and relay for each D2D pair. Then, we enhance the preliminary approach towards a comprehensive greedy algorithm for joint mode selection, relay selection, and resource allocation. We also address implementation aspects, including complexity, channel quality acquisition, and signaling message exchange for the management of the proposed solution for mobile users. The simulations demonstrate that our proposed scheme increases the sum rate of D2D pairs by approximately 20% if compared to the best performing related work.