Study On Multipair Relaying System Performance With Massive MIMO

Multiple-input multiple-output(MIMO)technology has now become an integral feature of many advanced communication systems.Massive MIMO is one of the most promising core technologies in 5G.Relaying technology has also been extensively ex-plored to provide expanded coverage and high throught,especially at the cell edge.Massive MIMO combined with cooperative relaying is a strong candidate for the de-velopment of future celluar networks.Therefore,this thesis focuses on multi-pair relay-ing systems with Massive MIMO.Firstly,the thesis considers a multi-pair amplify-and-forward(AF)relay channel and the relay station uses maximum ratio combining/maximum ratio transmission(MRC/MRT)and zero-forcing(ZF)with Orthogonal Scheme to process the signals.The thesis researches the asymptotic achievable rates of MRC/MRT,ZF and Orthogonal Scheme in three different power scaling laws and analyzes the system achievable rate and bit error rate in the regimes of different antenna number of relaying and transmit power.The simulation results show that the sum rate(bit error rate)in three different power scaling laws is increasing(decreasing)with the increase of the number of anten-nas firstly,then tends to a certain value;The certain value is the asymptotic achievable rate;The asymptotic achievable rates of MRC/MRT and ZF processing depend on the large scale fading effect.Secondly,the thesis considers a multi-pair full-duplex relaing system and assumes that the relay station employs MRC/MRT or ZF to process the sig-nals.The thesis researches an exact achievable rate expression in closed-form for MRC/MRT processing and an analytical approximation of the achievable rate for ZF processing.These closed-form expressions enable us to determine the regions where the full-duplex mode outperforms the half-duplex mode.The thesis analyzes the system performance in the regimes of different antenna number of relaying,transmit power and loop interference level.The simulation results show that increasing the number of transmit/receive antennas at the relay station can reduce the transmit power of each source and of the relay station while maintaining a given quality of service;At low loop interference level,the spectral efficiency of full-duplex relaying outperforms the spec-tral efficiency of half-duplex mode.However,when loop interference level is high,loop interference dominates the spectral efficiency of full-duplex mode and,hence,the spec-tral efficiency of half-duplex mode is superior;Using large antenna arrays at the relay station can reduce the effect of the loop interference;With the increase of antenna num-ber of relaying,the bit error rates of MRC/MRT and ZF processing will gradually ap-proach to a certain value in three different power scaling laws;By configuring a large number of antennas at the relaying,significant energy savings can be achieved without reducing the bit error rate.