Research On Uplink Multi-user Resource Allocation In Massive Mimo Systems

Massive MIMO(Massive Multiple input multiple output,MIMO)has become one of the key technologies of the fifth-generation mobile communication system(5G)because of its great advantages in improving spectral efficiency,energy efficiency and reducing inter-user interference.In the uplink transmission of a massive MIMO system,basestation is usually equipped with tens or even hundreds of antennas so that the transmission condition of users is greatly improved.As a result,the number of users reusing the same time-fr-equency resource can reach several tens.Therefore,when there are a large number of users in the cell,how to allocate limited time-frequency resources among users while considering factors such as algorithm complexity,user fairness,and user service priority,plays an important role in uplink massive MIMO system performance.In this paper,uplink multi-user resource allocation problem in massive MIMO systems is studied.This paper fir-st introduces the research background and significance of uplink multi-user resource allocation in massive MIMO systems.The intorduction focuses mainly on MIMO,which is the origin of massive MIMO technology.System model,channel capacity and capacity achived key transmission technologies of MIMO systems are introduced.Classic multi-user scheduling algorithms are introduced as well.Based on the above research,this paper proposes a channel correlation based uplink user grouping and resource allocation algorithm.The algorithm uses the proposed channel correlation and power based transmission quality factor to estimate the inter-user interference between multiplexed users,so as to avoid accurate user signal to interference and noise ratio calculation.The proposed algorithm considers the impact of uplink power control process when determining the number of time-frequency resources.Simulation results show that the proposed algorithm achieves an effective reduction of complexity with acceptable loss of performance.Next,based on the new scenario of the coexistence of eMBB and URLLC services required by 5G,this paper proposes two schemes for uplink eMBB and URLLC user multiplexing.The proposed algorithm takes the advantages of massive MIMO which supports large number of users reusing the same time-frequency resources.At the same time,in order to measure the efficiency of the use of system resources by URLLC users,a new criterion named URLLC user remain throughput is proposed.Simulation results show that the proposed criterion can truly reflect the spectrum utilization of URLLC UEs.Finally,the contribution of this paper is summarized and the future research direction is forecasted.