Analysis Of Effective Capacity Of Downlink In Non-orthogonal Multiple Access Systems

5G can provide a better user experience.NOMA(Non-orthogonal multiple access)technology is one of the important technologies in 5G technology.It can effectively improve the utilization efficiency of spectrum resources and has very important research value.However,the current research on NOMA technology focuses more on its power allocation scheme and user fairness,without much research and analysis on the impact of the delay constraint on the system in practical application.This thesis is to make a comparative analysis of NOMA(Non orthogonal multiple access)scheme and OMA(Orthogonal multiple access)scheme respectively based on the effective capacity theory.The superiority of NOMA scheme over OMA scheme under different SNR and two different delay constraints is discussed.Specifically,by constructing a two-user network,this thesis calculates the data rate and total effective capacity that each user can achieve at the link layer under different schemes and under different delay constraints,deduces the closed expressions of effective capacity for each user under different schemes,and constructs a simulation model for verification.At the beginning of the article,the development of mobile communication is introduced.By discussing the research progress of domestic and foreign research institutions and scholars in mobile communication technology,this thesis summarizes one of the key development directions of mobile communication technology in the emerging stage,namely non-orthogonal multiple access(NOMA),and gives a brief introduction of NOMA technology.At the same time,this thesis introduces the current research status of the effective capacity theory,which is put forward due to the requirements of different social strata on communication technology in different fields.In the theoretical part,the NOMA technical principle and effective capacity theory are explained in detail,and then a two-user network model is constructed.For this network,NOMA technology and traditional OMA technology are respectively proposed.The effective capacity of each user in two different schemes is deduced and the closed expression of effective capacity of each user is derived.On this basis,two schemes with different SNR and delay constraints are compared and analyzed reasonably by numerical calculation.On this basis,we can deduce the performance of a network with M users.Compared with the traditional OMA scheme,the advantages of the proposed two-user network NOMA scheme and multi-group NOMA over network NOMA scheme are obtained.Under high SNR,the NOMA scheme proposed in this thesis has better performance than OMA,and the difference of total effective capacity tends to be stable with the increase of SNR.Finally,the feasibility of the scheme is verified in the experimental simulation.