Energy-Efficiency of Full-Duplex-Enabled D2D Communications Underlaying Cellular Networks

This paper investigates the energy efficiency (EE) of device-to-device (D2D) communications underlaying cellular networks. Two transmission modes, full-duplex (FD) underlay mode and half-duplex (HD) underlay mode are considered. For each mode, we maximize the system EE while fulfilling the minimum rate requirements and maximum transmit power constraints for both cellular and D2D users. The parametric Drinklbach method is adopted to transform the optimal functions into a more tractable form. Then, we use the concave-convex procedure (CCCP) algorithm to obtain the optimal solution as the optimization problem can be transformed into a difference of convex functions (D.C.) programming. Finally, numerical results reveal how the channel gains and self-interference (SI) cancellation ability influence the EE.