SWIPT-Assisted Device-to-Device Communications Underlaying a Cellular System

Abstract

This paper considers device-to-device (D2D) communications assisted by simultaneous wireless information and power transfer underlaying a cellular multiple-input single-output system. In such a scenario, D2Ds are enabled to harvest the energy from the base station (BS) in the downlink (DL) transmission, and then D2Ds use the harvested energy for data transmission in the uplink (UL) transmission. The benefits of this model are not only to utilize the DL beamforming for energy harvesting but also to exploit the proximity connectivity of D2Ds for the reuse of energy in the data transmission. Accordingly, a two-stage scheme is proposed under the quality-of-service requirement of the both DL and UL cellular users, which is derived as the non-convex problems. Then, we propose the low-complexity algorithms based on an inner convex approximation to solve these problems. Numerical results verify that the energy harvested by D2D is efficiently reused for data transmission even under the realistic path loss model.