Research On Relaying Strategies For Two-way Full Duplex Relay System

Two-way full duplex(FD)relay,which allowing two communication nodes to perform bidirectional transmission through the FD relay at the same time and frequency,has become one of the most important research subjects of 5G system as a kind of efficient communication ways.This thesis mainly investigates two-way FD relaying strategy,which aims to give full play to the advantages of high spectral-efficiency(SE)and energy-efficiency(EE)of the system under complex self-interference introduced by FD technology.Firstly,a high-spectrum link selection strategy based on joint relay and transmit/receive(Tx/Rx)antenna selection is proposed for the two-way FD AF multi-relay system with two separated antennas at each node.In this strategy,each node adaptively selects its Tx antenna and Rx antenna based on max-min signal to interference and noise ratio(SINR),and the optimal relay and the best Tx/Rx antenna configuration is selected jointly in optimizing system performance.Then,its upper bound of achievable rate and the closed-form expression of the symbol error rate is analytical derived.Monte-Carlo simulations are fulfilled to verify the analytical expressions and make the comparison with traditional scheme.The results reveal that the proposed scheme can obtain 75%data rate gain and several times bit error rate decreased.Secondly,for the two-way FD AF MIMO relay system with multiple shared antennas at each node,an energy-efficient relaying strategy based on joint relay antenna selection and power adaption is proposed,which aims at maximizing EE with limited SE and node power constraints.In this strategy,it selects the best subset of Tx/Rx antennas at relay nodes,and determine the optimal transmit power at each node.Specifically,the proposed strategy is based on the idea of loop iteration and selects a pair of Tx/Rx relay antenna that achieves the largest increment of EE at each iteration.The optimal transmission power at each node is updated immediately by using the tool of fractional programming under certain selection.Simulation results show that the proposed scheme can achieve significant EE improvement and power consumption degradation with lower complexity than conventional scheme.In conclusion,the two-way FD relaying strategies proposed in this paper has great advantages in improving system SE and EE,and ensure communication reliability.These schemes provides theoretical support for two-way FD relay transmission in the actual system environment in the future,and has certain application value.