非理想连续干扰消除下非正交多址接入上行传输系统性能分析

Performances Analysis in Uplink Non-Orthogonal Multiple Access System with Imperfect Successive Interference Cancellation

非正交多址接入(NOMA)技术允许多个发送方共用同一个资源块,接收方通过连续干扰消除(SIC)解码出不同发送方的信息。然而,目前针对NOMA系统的研究大多基于理想SIC的假设,而没有考虑非理想SIC对系统性能带来的影响。针对此问题,该文在非理想SIC的假设下,针对单小区上行NOMA系统提出一套性能分析框架。首先,采用二项式点过程(BPP)对上行NOMA系统中基站和用户设备的空间分布进行建模。基于此模型,采用基于大尺度衰落的干扰消除顺序,对干扰消除的误差情况进行分析。进一步,基于随机几何理论和次序统计理论,推导出距基站由近至远次序为k的用户设备的覆盖概率,并采用平均覆盖概率衡量整个NOMA传输系统的可靠性。理论和仿真结果分析了远近次序、基站半径和发射功率等系统参数对传输可靠性的影响,并验证了理论推导的准确性。

Non-Orthogonal Multiple Access(NOMA)serves multiple transmitters using the same resource block,and the receiver decodes the information from different transmitters through Successive Interference Cancellation(SIC).However,most of the researches on NOMA systems are based on perfect SIC assumption,in which the impact of imperfect SIC on NOMA system is not considered.Focusing on this problem,a framework is provided to analyze the performance of single-cell uplink NOMA system under the assumption of imperfect SIC.Firstly,the Binomial Point Process(BPP)is used to model the spatial distribution of base station and user equipment in uplink NOMA system.Based on this model,the interference cancellation order which is based on large-scale fading is adopted,and then the error of interference cancellation is analyzed.Then,based on stochastic geometry theory and order statistics theory,the expression of coverage probability of user equipment which is at rank k in terms of the distance from the base station is derived,besides,the average coverage probability is adopted to reflect the reliability of NOMA transmission system.The analytical and simulation results show the influence of system parameters such as distance order and base station radius on transmission reliability.Also,the validity of theoretical deduction is verified.