Study Of Full-Duplex Relay System Based On Swipt And Self-Energy Recycling

An energy harvesting wireless network is a wireless network with energy harvesting devices at the nodes.It can convert many forms of wireless energy harvested from the surrounding environment into power that can be supplied,and instead of traditional wired electricity or batteries to power wireless devices in the network.Information transmission and energy harvest technology based on radio frequency signals has become an alternative method of transmitting data and providing power in a new generation of wireless communication networks,and exploring new methods or technologies to improve the performance of wireless systems to promote wireless networks development plays a vital role.Because the RF signal in a wireless energy harvest network that supports radio frequency is both a carrier of information and a carrier of energy,the use of SWIPT technology to realize the synchronous transmission of information and energy in wireless networks has become the development trend of future research.In this era of high-speed Internet development,higher requirements are placed on the operating efficiency and system performance of wireless networks.However,in the current research on wireless relay systems,there is no in-depth discussion on the application scenario of SWIPT technology combined with self-energy recycling technology,and the relay transmission protocol adopted by the system is based on time-segment transmission.This leads us to make further research on the wireless relay system to meet the current needs of people on the network.This paper aims at improving the transmission efficiency and performance of the wireless relay system,and conducts theoretical analysis and application research on the full-duplex relay system with self-energy recycling using SWIPT technology.Through the introduction of full-duplex relays in wireless networks for cooperative transmission,the application of SWIPT technology realizes the transmission of information and energy based on RF signals.The thesis mainly carried out research work in the following two aspects:(1)Aiming at minimizing the system transmission power sum as an optimization goal,a two-way transmission full-duplex relay system based on SWIPT and self-energy recycling is proposed.And the logical structure of the full-duplex relay system and the physical structure of the destination node with limited energy are given.In this two-way transmission relay system,the relay sends dedicated energy to the energy-constrained destination node,and the destination node can recover energy from the loop channel.A power splitting scheme is used for information decoding and energy harvest,and a mathematical model for communication transmission is established.For problem solving,the semi-definite programming and rank relaxation methods are used to convert the original non-convex optimization equation into a solvable convex optimization problem for solving,and the relay transmit power,transmit beamforming vector and power splitting ratio are jointly optimized to improve the performance of the system gain.Comparing the simulation experiment results,it is shown that the two-way transmission full-duplex relay system based on SWIPT and self-energy recycling proposed in this paper can not only eliminate self-interference but also significantly optimize the system transmission power sum by using self-energy recycling technology.What’s more,due to the combination of SWIPT technology and full-duplex relay system,the performance of the system is better than the traditional two-way transmission relay system.(2)To maximize system throughput as an optimization goal,a non-time-sharing SWIPT full-duplex relay system with an energy access points in a radio frequency network is proposed.In order to make full use of the energy resources in the energy harvesting wireless network,the system uses idle wireless terminal equipment that can store electrical energy as an EAP to provide supplementary energy for the relay,and the energy-constrained relay can harvest proprietary energy from the source node or harvest supplementary energy from external EAP to supply the power consumption for the relay to work normally.The system considers a full-duplex relay system with a single EAP and multiple EAPs,and analyzes the relationship between the proprietary energy harvested by the relay from the source node and the supplementary energy harvested from the EAP.What’s more,a model of a full-duplex relay system is constructed,and a non-time-sharing relay system transmission protocol is proposed,which realizes that information transmission,energy harvesting and cooperative transmission are synchronized in the same time slot block,which improves the efficiency and performance of the relay system.The system uses a power splitting scheme to separately perform decode information and harvest energy on the RF signals transmitted by the SWIPT technology,and relays forwards the received information signals to the destination node.Moreover,the system performs self-energy recycling through the loop channel at the relay,and at the same time achieves the purpose of the system eliminating self-interference signals.The system uses quadratic optimization,variable reduction and other methods to convert the original multivariate non-convex problems into semi-definite programming problems,and uses the Lagrange method to solve the problem.The simulation experiment results show that the non-time-sharing SWIPT full-duplex relay system with energy access point proposed in this paper has better throughput under the DF protocol than the system throughput under AF protocol;and when the energy harvested by the relay from the source node is limited,increasing the energy harvested from the EAP can effectively increase the operating speed of the proposed relay system.The experiment also verifies that compared with HD-SWIPT and FD-No-SWIPT relay system,the proposed non-time-sharing SWIPT full-duplex relay system has better gain in improving system performance.The research work in this paper has made some progress.A two-way transmission full-duplex relay system based on SWIPT and self-energy recycling,and a non-time-sharing SWIPT full-duplex relay system with energy access points are proposed.In order to apply SWIPT technology,non-time-sharing transmission protocol,energy access point and self-energy recycling in wireless relay systems to realize the synchronous transmission of wireless information and energy in wireless systems,improve system throughput and performance,and expand wireless network transmission,providing new research ideas and technical means.Research work has academic value and scientific significance.