Non-time-Sharing Full-Duplex SWIPT Relay System with Energy Access Point

Abstract

Utilizing the idle wireless devices with energy as an additional energy access point (EAP) to supplement energy for the relay, a non-time-sharing full-duplex amplification and forwarding (AF) relay system with energy access points based on radio frequency (RF) signals in wireless networks is proposed. Using AF protocol to cooperative transmit information and simultaneous wireless information and power transfer (SWIPT) technology to realize information and energy synchronous transmission in the energy-constrained relay system. The relay can eliminate the self-interference signal through self-energy recycling in the loop channel, and adopts power splitting scheme for information decoding and energy harvest for RF signals. Moreover, due to the non-time-sharing transmission characteristics, information transmission, energy harvest and cooperative transmission are completed synchronously in a time block. Taking maximize system throughput as optimization target, jointly optimizing the relay transmit power, the relay transmit beamforming vector and the power splitting ratio, and the system transforms the original multivariate non-convex problem into a semi-definite programming problem by using quadratic optimization, variable reduction methods and Lagrange method. Simulation experiments show that under the condition that the total energy harvested is fixed, the operation rate of the system can be promoted effectively by increasing the energy harvested from EAP. And the self-energy recycling of the relay can promote the throughput gain of the system. The experimental results also verify that our proposal the system based on applying non-time-sharing transmission protocol and SWIPT technology has more significant gains in improving system performance than HD-SWIPT and FD-no-SWIPT relay systems.