Performance Analysis Of Ris-aided Massive MIMO Systems With Transceiver Hardware Impairments

The explosive growth of mobile data traffic,as well as the emergence and popularization of innovative applications such as fully immersive virtual reality,holographic communications,smart transportation systems and drone-delivery systems make the future wireless communication system not only need extremely high data rate and ultra-low delay,but also ensure seamless coverage,uninterrupted connection and ultra-high reliability.Reconfigurable Intelligent Surface(RIS)can help future wireless communication systems meet the above requirements.It has low hardware cost and power consumption,and can reconfigure the wireless propagation environment.More importantly,it can be seamlessly integrated into existing cellular networks or Wi Fi systems.On the other hand,wireless spectrum resources are increasingly scarce.Compared with seeking spectrum resources from Tera Hertz(THz)and other high-frequency bands,Full-Duplex(FD)is considered to be a more feasible and effective method to improve spectrum utilization.In addition,in the practical scenario,the transceiver hardware impairments(THWIs)are inevitable.Therefore,this paper studies an RISaided m MIMO communication system based on THWIs in multi-cell and FD scenarios,where the channel is modeled as Rician fading channel,and the phase shifts of RIS are designed by the more practical and feasible two-time scale schem.This paper first considers an RIS-aided uplink massive multiple input multiple output(m MIMO)communication system with THWIs,and the maximum ratio combining(MRC)technology is used to process the signals at the base station(BS)when the channel state information(CSI)is available,the expression of uplink achievable rate is derived and analyzed.Then,only based on statistical CSI,genetic algorithm(GA)is used to optimize the phase shift at RIS to maximize the sum rate and maximize the minimum user rate.Finally,Monte-Carlo(MC)simulation is used to verify the accuracy of the derivation.The research shows that in the RIS-aided uplink m MIMO system with THWIs,we can greatly reduce the demand for the number of BS antennas by appropriately increasing the number of RIS’s elements,which will effectively reduce the hardware cost of BS;When both the number of reflecting elements N and the number of BS antennas M maintain a large value,the fairness of users can be guaranteed while the sum rate is maximized,and the objective function ’ max-sum rate ’ can be replaced by ’max min-rate’,which can significantly reduce the optimization cost and time.Secondly,this paper studies an RIS-aided uplink multi-cell m MIMO communication system with THWIs,where the inter-cell interference is considered.MRC technology is used to process the signal at the BS.The expression of uplink achievable rate is derived and analyzed,and GA is used to optimize the phase shift of RIS.Finally,the accuracy of the derivation is verified by MC simulation.The research results show that in the RIS-aided uplink multi-cell m MIMO system with THWIs,through increasing the number of RIS’s elements,the performance loss caused by inter-cell interference and THWIs can be compensated,and the demand for the number of BS antennas can be greatly reduced;When the number of reflecting elements N and the number of BS antennas M are both large,the maximum sum rate and fairness of users can be guaranteed at the same time,and the objective function ’ max-sum rate ’ can be replaced by ’max min-rate’,which can significantly reduce the optimization cost and time.Finally,an RIS-assisted FD m MIMO communication system with THWIs is proposed in this paper.MRC/Maximum Ratio Transmission(MRT)technology is used at BS to process the received and transmitted signals.The expressions of the uplink and downlink achievable rate are derived and analyzed.Then,based on statistical CSI,the phase shift of RIS is optimized by GA.The accuracy of the derived expression is verified by simulation.The simulation results show that in the RIS-aided FD m MIMO system with THWIs,we can greatly reduce the demand for the number of BS transceiver antennas by appropriately increasing the number of RIS’s elements,which will significantly reduce the hardware cost at BS.