基于NOMA的全双工多层异构网下行链路覆盖分析

Coverage Probability Analysis of Downlink About Full-Duplex Multi-tier HetNet Based on NOMA

针对异构网(Heterogeneous Network,HetNet)无线回程,现有研究主要集中于提升网络吞吐量,而对回程覆盖性能研究较少.由此,本文构造了一种在小小区基站(Small cell Base Station,SBS)上结合全双工(Full-Duplex,FD)和非正交多址接入(Non-Orthogonal Multiple Access,NOMA)技术的大规模多输入多输出(Multiple Input Multiple Output,MIMO)辅助多层HetNet模型.利用信干比(Signal-to-Interference Ratio,SIR)来模拟有源SBS的分布,得出不同类型接收端的干扰;然后推导了移动用户(Mobile User,MU)下行链路覆盖概率闭合表达式.仿真和数值结果表明,SBS下行链路覆盖概率会随着小小区下行链路功率共享系数的增加而减小;此外,通过对比NOMA和正交多址接入(Orthogonal Multiple Access,OMA)以及FD和半双工(Half-Duplex,HD)对下行链路覆盖性能的影响,本文提出的方案能显著提升网络性能.

For wireless backhaul of heterogeneous networks(HetNet),the existing researches mainly focus on improving the network throughput.However,few research is done on the coverage performance in the backhaul link.Therefore,this paper constructs a massive multiple input multiple output(MIMO)enabled multi-tier heterogeneous network model combing full-duplex(FD)and non-orthogonal multiple access(NOMA)technologies on small cell base stations(SBSs).The signal-to-interference ratio(SIR)is utilized to simulate the distribution of active SBS,and the interference is obtained at different types of receivers.Then,the mobile user(MU)downlink coverage probability closed-form expressions are deduced.Simulation and numerical results show that the SBS downlink coverage probability decreases as the downlink power sharing coefficient of the small cell increases.In addition,by comparing the effects of NOMA and orthogonal multiple access(OMA),FD and half-duplex(HD)on downlink coverage performance,network performance of the proposed scheme is significantly improved.