Performance Analysis Of NOMA Based On Two-Tier Heterogeneous Cellular Networks

With the improvement of communication level,Internet of Things has become the trend of the future,and the number of terminal access in cellular network also shows explosive growth.Traditional cellular network technology has been unable to meet the existing demand,various technologies have been proposed to solve the network capacity and communication rate,among which,the heterogeneous cellular network is one of the core technologies used to improve the network capacity.Heterogeneous cellular network technology improves the load capacity of the whole network by deploying base stations with different multi-layer densities.In addition,to solve the problem of limited spectrum resources,Non-Orthogonal Multiple Access(NOMA)technology enables multiple users to share the same frequency band through the orthogonal power domain.The receiver demodulates the signal by introducing interference elimination technology,which also satisfies the quality of service of the receiver.Therefore,the combined application of heterogeneous networks and Non-Orthogonal Multiple Access technology has attracted a lot of attention and rich research results.The purpose of this paper is to study the application scenarios and performance of the NOMA technology in the two-tier heterogeneous cellular network.According to the maximum power access strategy,the user will select the base station according to the maximum signal of the receiving end.In this model,different types of users connected to the same base station form the NOMA group.In addition,according to the distribution of heterogeneous network micro base station,it can be divided into two scenarios: the uniform distribution and the non-uniform distribution.In the non-uniform distribution,a user matching scheme is proposed to improve the signal quality of users.In the uniform distribution,to solve the problem of signal quality of edge users,a base station collaboration strategy will be introduced,in which the edge users will receive signals fromboth the macro station and the micro base station at the same time,and the coverage rate and accessible rate of different users will be obtained through NOMA pairing.This paper deduces the coverage probability,accessibility rate and energy efficiency of the whole network under the different scenarios,analyzes the influence of the coverage probability of the different system parameters and other indicators,and uses Monte Carlo simulation to verify the correctness of the results,and compares the performance differences between the orthogonal multiple access technology and the NOMA technology under the same scenario.At the same time,the proposed user matching scheme is compared with other user matching schemes to verify the advantages and the disadvantages of the proposed strategy.Finally,the paper compares the coverage probability,accessibility rate and energy efficiency of two different scenarios,and comprehensively analyzes the difference of network performance in different scenarios.