Research On The Weighted Least Mean Square Error Relay Emission Beamforming Method Based On A Full-duplex Two-way Relay System

In recent years,with the in-depth research,the full-duplex relay communication system can not only expand the coverage of communication services,but also further improve the spectrum utilization efficiency of the system and the data transmission rate of communication,which has been widely concerned by research scholars all over the world.the full-duplex relay communication system can simultaneously transmit and receive signals at the same frequency and time,so the spectral efficiency can be doubled compared to the half-duplex relay communication system.However,there is signal leakage between the relay transceivers of the full-duplex relay communication system,which will lead to the problem of self-interference,seriously deteriorates the performance of the relay communication system.Therefore,it is a challenge to realize the full-duplex technology is how to effectively eliminate the self-interference caused by full-duplex.This paper mainly focuses on the full-duplex two-way relay system,and focuses on the research on the relay transmit beamformer based on the Weighted minimum mean square error(WMMSE)algorithm.The main research work is as follows:(1)The design of the transmit beamformer at the relay of a full-duplex two-way relay(FD TWR)system with a single pair of information sources is considered.First,a single-pair information source FD TWR system is modeled.Both source nodes of the system are equipped with multiple antennas,and each nearby relay node is equipped with two antennas,one for transmission and the other for reception.Then,an iterative linear relay transmit beamformer based on WMMSE algorithm is designed.Under the constraints of limited transmit power and ZF return to zero at the relay,the initial design model of the transmit beamformer at the relay is established using the criterion of maximizing the weighted information and transmission rate.This design problem is equivalent to a matrix weighted sum MSE minimization problem,which can be solved using the WMMSE algorithm.In order to facilitate the comparison,an iterative linear relay beamformer based on the algorithm of maximizing the small signal-to-noise ratio of the source node and the algorithm of minimizing the mean square error is also designed.Finally,numerical experiments evaluate the effectiveness and efficiency of the WMMSE beamformer by simulating the average sum transfer rate and average running time.(2)Based on the FD TWR system model of a single pair of information sources,the design of the transmit beamformer at the relay of a full-duplex two-way relay system with multiple pairs of information sources is considered.For the distributed realization of FD TWR system with multiple pairs of information sources,three algorithms are proposed,namely distributed WMMSE algorithm,distributed SNRMAXMIN algorithm and distributed MMSE algorithm,and discussed computational complexity of these three distributed algorithms.Finally,the effectiveness and efficiency of the distributed algorithm are verified by weighted average sum rate and CPU running time.