Energy efficiency optimization of relay-assisted D2D two-way communications with SWIPT

Aiming at the energy consumption of long-distance device-to-device(D2D) devices for two-way communications in a cellular network,this paper proposes a strategy that combines two-way relay technology(TWRT) and simultaneous wireless information and power transfer(SWIPT) technology to achieve high energy efficiency(EE) communication.The scheme first establishes a fractional programming problem to maximize EE of D2D,and transforms it into a non-fractional optimization problem that can be solved easily.Then the problem is divided into three sub-problems:power control,power splitting ratios optimization,and relay selection.In order to maximize EE of the D2D pair,the Dinkelbach iterative algorithm is used to optimize the transmitted power of two D2D devices simultaneously;the one-dimensional search algorithm is proposed to optimize power splitting ratios;an improved optimal relay selection scheme based on EE is proposed to select relay.Finally,experiments are carried out on the Matlab simulation platform.The simulation results show that the proposed algorithm has faster convergence.Compared with the one-way relay transmission and fixed relay algorithms,the proposed scheme has higher EE.