Energy-Efficient Channel Reusing for Device-to-Device Communications Underlying Cellular Networks

Energy efficiency (EE) has become an increasingly important issue in Device-to-Device (D2D) communications since wireless terminals are hand-held equipments with limited battery life. In this paper, an energy-efficient channel reusing scheme for multi-D2D links is proposed. We first analyze the EE of a single D2D link in both non-cooperative mode (NCM) and cooperative mode (CM), and prove that the EE of the D2D link is mainly determined by the location of the cellular user equipment (CUE) that shares resource with the D2D pair. On this basis, a location-based algorithm (LBA) is proposed to select the optimal CUE for each of the D2D pairs, aiming to maximize the sum EE of all D2D links. Numerical results show that the proposed LBA could effectively improve the overall EE of the D2D system while guaranteeing the target rate of each D2D link. Moreover, the proposed LBA does not require the channel state information (CSI) of all the involved links, which could significantly reduce the feedback overhead and computational complexity.