Mode selection and resource allocation for device-to-device communications in 5G cellular networks

To meet the increasing demand of wireless broadband applications in future 5G cellular networks, Device-to-Device (D2D) communications serve as a candidate paradigm to improve spectrum efficiency. Considering the challenges after D2D transmission is introduced for future cellular networks, this paper deals with mode selection and resource allocation issues related with D2D communications. First, we propose a mode selection scheme which aims at guaranteeing the transmission of cellular users and also considering the potential interference. We analyze the condition under which D2D underlay mode should be used. Second, we answer the question of “how to effectively reuse cellular resource once underlaying mode is adopted”. We further present a resource allocation scheme that focuses on minimizing overall interference as well as a power control method to improve the performance of D2D systems. Simulation results demonstrate that system parameters greatly affect the switching condition of mode selection and probability of choosing underlay mode. Furthermore, for D2D underlaying scenario, the proposed resource allocation algorithm guarantees the transmission of cellular users with consideration of transmission requirements of D2D users. Hence, the proposed scheme can achieve better user experience.