Research On Relay Selection Optimization Based On Full Duplex Multi-Relay Cooperative SWIPT Network

With the rapid development of wireless communication technology and the large-scale deployment of 5G networks,a new era of the Internet of Everything has opened up.The number of Io T nodes such as sensors and other low-cost and low-power devices is growing exponentially.Most Io T nodes exist in wireless networks in the form of wireless devices,and the continuous operation of wireless devices relies on built-in batteries for power supply.However,since the battery capacity is limited,it is impossible to power wireless devices for a long time without charging or replacing them.Massive wireless devices bring huge labor operation and maintenance costs.Providing energy for wireless devices continuously needs to be solved urgently.The emergence of simultaneous wireless information and power transfer(SWIPT)technology,which takes advantage of the fact that wireless electromagnetic waves can carry information and energy at the same time,provides a new idea for solving the energy supply problem of wireless devices.With the advantages of the convenience of wireless energy transmission and the controllability of radio frequency signals,SWIPT has attracted extensive attention of researchers.In this paper,SWIPT technology is applied to the traditional relay cooperative communication network,and the research is mainly carried out on the full duplex(FD)multi-relay cooperative transmission scheme based on power splitting(PS)strategy.Mainly from the perspective of system capacity and outage probability,this paper firstly studies various relay selection(RS)algorithms in PS-based unidirectional transmission FD multi-relay cooperative SWIPT network,and proposes a HTEA(Harvest then Exhaust All)power consumption scheme to optimize system performance.Then,in the PS-based bidirectional transmission FD multi-relay cooperative SWIPT network,a relay cooperative transmission scheme based on frequency division duplex(FDD)is proposed.By introducing FDD technology,the power redistribution of signals in different frequency bands at the relay is realized.Simulation experiments show that the two optimization schemes have certain practical significance in their respective systems.The main research work and innovation points of this paper are as follows:1.For PS-based unidirectional transmission FD multi-relay cooperative SWIPT network,from the perspective of optimal system capacity,a new HTEA power consumption scheme is proposed.As for the proposed HTEA power consumption scheme,two application scenarios,battery information known at transmitter(BIKT)and battery information unknown at transmitter(BIUT),are considered and analyzed.Simulation experiments show that under the new HTEA power consumption scheme,whether applied to BIKT or BIUT scenarios,multiple RS algorithms can achieve performance improvement in system capacity and outage probability.2.Aiming at PS-based bidirectional transmission FD multi-relay cooperative SWIPT network,a relay cooperative transmission scheme based on FDD is proposed.The scheme can support FDD communication by redesigning the logic structure of the receiver at the relay,and it realizes the power redistribution of signals in different frequency bands at the receiver.Taking the optimal single-link outage probability as the goal,the optimal PS coefficient and the optimal signal power distribution coefficient are obtained.Simulation experiments analyze the performance and applicable scenarios of various RS algorithms under this scheme.