Studies On Interference Elimination Technology Of Multicell Massive MIMO Systems With Dual Antenna Users

With development and progress in society,people's demand for the performance of wireless communication system is growing.Achieving a high-rate,high-stability and low-power comsumption wireless mobile communication network to meet the increasing need of people,is an opportunity and also a challenge for researchers.Currently,the research about the fifth-generation(5G)wireless communication network has attracted many focuses.The 5G system will be deployed and used for commercial applications by the year of 2020.There are a lot of key technologies which has been many focused in the 5G system.Among that,massive Multiple-input multiple-output(MIMO)technology gets most of the attention due to its outstanding advantages.Although significantly improving system performance,massive MIMO technology also faces many challenges.The interference in massive MIMO system which is also known as pilot contamination,is one of them.Therefore,under the premise of ensuring system performance,how to overcome the effects of pilot contamination and eliminate the interference in massive MIMO is a problem to be solved.Based on the key technologies in massive MIMO system,this paper analyzed the mechanism of pilot contamination in multicell massive MIMO system.The aim of this paper is to eliminate or mitigate the effects of the system,so as to achieve the purpose to enhance the system performance.The main contents are as follows.Firstly,we propose an approach to eliminate or mitigate the effects of pilot contamination in multicell massive MIMO system with dual antenna user equipment.Given the spatial correlation of channel matrix between two user antennas,the optimal beamforming weight vector is obtained explicitly.By leveraging the proposed beamforming weight vector we can achieve the purposes of mitigating channel estimation error and improving the system rate.Simulation results show that compared with the existing single-antenna user equipment,the proposed method can greatly reduce the impact of pilot contamination.Secondly,we introduce the pilot scheduling schemes into the proposed method above and we propose the pilot assignment based on greedy algorithm and Tabu search algorithm.Combined with the dual antenna user equipment,we further mitigate the impact of pilot contamination.Simulation results show that the proposed method can improve the system performance no matter in channel estimation error or achievable sum rate.