Energy efficiency optimization of D2D communications with SWIPT and NOMA

Abstract

In order to balance the relationship between D2D users' capacity and energy consumption in a cellular network, an energy-saving transmission mechanism based on non-orthogonal multiple-access (NOMA) enhancement is designed in this paper to increase the number of D2D multiplexing of limited cellular resources. At the same time, to reduce the energy overhead of relay, the idle D2D is used as a relay node and the simultaneous wireless information and power transfer (SWIPT) technology is used to compensate its own energy consumption in the forwarding process. In this paper, a nonlinear fractional programming problem is established to maximize the energy efficiency (EE) of D2D clusters. To overcome the non-convexity of the objective function and the coupling of parameters, we solve the approximation of the original optimization problem based on fractional programming and sequential convex approximation theory. First, the maximum energy efficiency is obtained by dichotomy; Then the sequential convex approximation method is used to solve the corresponding optimal transmitting power; Finally, genetic algorithm is used to get the optimal configuration parameters of the system; The above steps are alternately iterated until convergence to obtain the optimal solution. The simulation results show that the algorithm we proposed has faster convergence and is better than the orthogonal multiple access (OMA) technology in the improvement of energy efficiency performance.