Research On Novel Non-orthogonal Multiple Access And Precoding Technology

With the development of communication technology,especially the popularization of intelligent mobile terminal equipment,there has been an increasing demand for the data volume transmitted by the next generation wireless network,which urgently requires the wireless communication system to solve some major demands,such as improving spectrum efficiency,increasing system capacity,reducing delay and improving service quality.However,due to the user exclusivity of orthogonal resources,the existing orthogonal multiple access technology with its current user volume and spectrum efficiency cannot meet the application requirements of the next generation wireless communication.Novel non-orthogonal multiple access and MU-MIMO technology allows non-orthogonal resource allocation to control interference,which makes the resources in the same block capable of providing service for multiple users at the same time.Compared with the traditional orthogonal multiple access technology,non-orthogonal multiple access technology and MU-MIMO technology have the advantages of improved spectrum efficiency,the connectedness of mass,low transmission delay and signaling cost.Therefore,non-orthogonal multiple access technology and MU-MIMO technology have become a key focus of academia and industry,as well as the research and applicaiton of the next generation of wireless communication technology.This paper mainly makes an in-depth study of the novel non-orthogonal multiple access technology and the precoding technology in the MU-MIMO system.The main work and innovations are summarized as follows:1.This paper studied the three types of popular non-orthogonal multiple access technology.On this basis,in order to further improve spectrum efficiency and better performance of the system,this paper proposes a non-orthogonal multiple access technology combined with universal filtered multi-carrier.According to theoretical analysis and experimental simulation results,the proposed sparse code multiple access combined with universal filtered multi-carrier scheme can effectively improve the system spectrum efficiency,and reduce the system bit error rate.The rationale behind this is that the code book sparse characteristics,the universal filtered multi-carrier multiplexing of the modulator and demodulator,as well as the system approximate optimal information transfer detection algorithm and other characteristics together make the system have better performance.2.In 5G/B5G mobile communication system,MU-MIMO system is also a non-orthogonal access method.The biggest challenge in the MU-MIMO system is to design an optimal precoding scheme for users to reduce interference from other users.In this paper,an improved channel matrix based on the minimum mean square error is considered.In the case of incomplete channel state information,a precoding scheme based on SLNR criterion is proposed.Compared with the traditional precoding algorithm,this scheme can effectively reduce the bit error rate of the system without the loss of sum rate.3.In non-orthogonal multiple access scheme,user scheduling is very important in the actual communication process because of the limitation of system resources.However,due to its high computational complexity,the optimal exhaustive search user scheduling algorithm is difficult to implement.Therefore,based on the above precoding scheme,this paper proposes a new user scheduling scheme based on the SLNR criterion.By using the SLNR criterion to maximize the weighted sum rate,the complexity of the system is effectively reduced.The average sum rate performance is basically the same as the traditional approximate optimal algorithm,and a trade-off between performance and complexity is realized.