Research Of MIMO-NOMA Based On Quality Of Service

With the increasing demand for Internet,the continuous innovation and optimization of modern Internet technologies,the emergence of various fields such as smart manufacturing,smart cities,and Internet of everything,the demand for communication systems in various fields is getting higher and higher.People expect communication systems to provide higher capacity and higher spectrum efficiency to support more users and more application scenarios.In this context,the fifth-generation communication technology 5G faces many challenges.In order to meet the demand for communication systems,5G needs to overcome several technical challenges,such as higher spectrum utilization,higher data transmission rates,and lower latency.Only through continuous technological innovation and optimization can 5G truly fulfill people’s expectations for communication systems.Non-Orthogonal Multiple Access(NOMA)technology and Multiple Input Multiple Output(MIMO)technology are the key to 5G technology and the key technology for future mobile communications,which can continuously enhance the additional system capacity by It is a key technology for the future of mobile communications,enabling higher spectral efficiency through multiplexing in the power and air domains while increasing additional system capacity.In the future,the combination of NOMA and MIMO can significantly improve system capacity and spectral efficiency,and provide the basis for the quality of service(Qo S)of users’ information life,driving the digital and intelligent development of society.Each user in the MIMO-NOMA system transmits in the power domain non-orthogonal superposition on the same time-frequency resource block,and multiple signals are superimposed at the transmitter side through power multiplexing,and then demodulated at the receiver side through the Serial Interference Cancellation(SIC)technique.In order to improve system capacity,spectral efficiency and user Qo S,proper user clustering algorithm and power allocation algorithm are essential.The user clustering algorithm can divide users into different user clusters according to different channel differences,and the power allocation algorithm then allocates resources according to different channel differences of users.However,different clustering algorithms and power allocation algorithms have an impact on user Qo S.Therefore,this paper focuses on the research of key technologies in downlink MIMO-NOMA system with user Qo S as the premise,and the main research contents are as follows:(1)The basic principles of NOMA technology and MIMO technology are studied,and NOMA technology and OMA technology are compared.The key technologies of MIMO-NOMA are studied and the system model of downlink MIMO-NOMA system is analyzed,and finally the difference of signal transmission in the system uplink/downlink of MIMO-NOMA system is compared.(2)The power allocation algorithm to maximize the total rate in the downlink two-user MIMO-NOMA system is investigated.First,we elaborate each classical user clustering algorithm and user power allocation algorithm,and analyze the advantages and disadvantages of each power allocation algorithm by simulation.Then,an improved MIMO-NOMA user power allocation algorithm is proposed with the goal of maximizing the total user rate.Simulation results show that the proposed MIMO-NOMA power allocation algorithm further improves the system throughput performance,but fails to guarantee the fairness of users due to its poor fairness.(3)Finally,the focus is on exploring the power allocation scheme to increase the user rate fairly in the downlink two-user MIMO-NOMA system.First,the Jain fairness index is introduced to measure the user fairness in the system,and the classical power allocation algorithm is analyzed and compared for user fairness.Then,the minimum power required for each cluster is calculated based on the channel conditions and the minimum rate demand of each user,and the relationship between the maximum value of the minimum rate increased by two users in a single cluster and the total power of the cluster is derived on the basis of satisfying the minimum rate demand of the users,based on which the power allocation optimization problem of increasing the rate of each user fairly under the condition of satisfying the minimum rate demand of the users is established,and the simulation results show that The simulation results show that the minimum rate increase and the outage probability of users in the proposed scheme further improve the Qo S of users and ensure the user fairness.