Resource Allocation Algorithms For Power-Domain NOMA Based Ultra Dense Networks

In order to realize the interconnection of all things,the 5th generation wireless mobile communication system(5G)needs access mode that can support massive links.Non-orthogonal Multiple Access(NOMA)technology in power domain,as an alternative technology for 5G multiple access,can make the system overload,increase the number of users serving the system,and thus improve the spectral efficiency of the system.Moreover,the receiver adopts Successive Interference Cancellation(SIC)detection,which makes the design of the receiver simple and low complexity.Ultra-Dense Network(UDN),as one of the key technologies of 5G,improves the system's regional spectrum efficiency by densification of base stations and rational allocation of resources in the cell.Combining power domain NOMA with ultra-dense networking can further improve the number of service users and spectral efficiency of the system.This thesis mainly studies the resource allocation algorithm and performance of ultra-dense networking based on power domain NOMA.Firstly,by analyzing the power allocation mode of two-user NOMA,this thesis proposes an optimal power allocation scheme to ensure the quality of user communication,named Threshold Power(TP)allocation scheme,and then deduces the capacity gain based on this power allocation scheme.Furthermore,the error performance of two-user NOMA is further studied,and the closed expression of theoretical error rate is given.Then the spectrum efficiency and energy efficiency of power domain NOMA combined with ultradense networking are analyzed and verified by simulations.Secondly,aiming at the problem of resource allocation in heterogeneous networks with single-rate services,the heterogeneous network system combining power domain NOMA with ultra-dense network is proposed.Aiming at this system,user selection matching and power allocation of macro-base station and micro-base station are discussed.Suboptimal user matching algorithm and optimal power allocation algorithm based on Hungarian algorithm are given,and macro-base station and micro-base station are given.Base station cooperative game algorithm has approached the local optimal solution of the system.Finally,aiming at the resource allocation problem of heterogeneous network systems with multi-rate services,the effects of three kinds of services on resource allocation schemes of heterogeneous network systems are discussed.According to the different service rates and bandwidth of different services,the Business Replacement Matching(BRM)algorithm based on greedy algorithm and the Ladder Waterfilling Power Allocation(LWPA)algorithm are proposed in this thesis.And simulations analyse of different business requirements on the performance of the system.