5G移动通信网络中非正交多址接入技术系统级性能仿真分析

发布时间：2018-11-05 07:21

【摘要】：作为移动通信系统最核心的技术,多址技术直接决定了系统的性能与容量。前四代移动通信系统均基于正交多址接入技术,用户间互不干扰,不需要复杂的多用户检测因而降低了系统复杂度。然而,随着移动通信系统用户数量与高速率业务需求的迅速增长,这些正交多址技术受限于频谱效率与接入能力而难以满足未来移动通信需求。因此,面向第五代移动通信系统(5G),有效提升系统容量的非正交多址技术研究受到广泛关注。本论文针对 SCMA(Sparse Code Multiple Access)和 NOMA(Non-orthogonal MultipleAccess)这两种最具代表性的非正交多址技术进行了仿真,基于仿真结果,分析了干扰、功率分配等对系统性能的影响。论文首先对SCMA系统模型与关键技术进行了简要分析,并以此为基础介绍了SCMA系统仿真平台,包括平台基本参数和平台仿真流程图等,特别讨论了基于平台的SCMA非正交多址技术仿真实现。基于平台,论文仿真了 OFDMA(Orthogonal Frequency Division Multiplexing Access)和 SCMA 两种系统,仿真结果表明,SCMA 在接入用户数量和系统吞吐量方面较OFDMA有更出色的表现。进一步,论文仿真分析了自适应调制编码对SCMA系统性能提升的影响以及小区内干扰对有用信号的影响。随后论文基于NOMA系统模型开展了 NOMA系统用户间公平性研究。基于拉格朗日乘子法以及小区公平指数(cell fairness index,CFI)和α效用函数,论文仿真了公平性约束下的功率分配优化算法,得到了在不同的小区用户数、不同的小区半径和不同的发射功率下,小区的小区公平指数、频谱效率和能量效率的变化曲线,得到的结论对于NOMA系统设计具有指导意义。
[Abstract]:As the core technology of mobile communication system, multiple access technology directly determines the performance and capacity of the system. The previous four generation mobile communication systems are based on orthogonal multiple access technology, which does not require complex multiuser detection, so the complexity of the system is reduced. However, with the rapid growth of the number of users and the demand of high-speed services in mobile communication systems, these orthogonal multiple access technologies are limited by spectrum efficiency and access ability to meet future mobile communication requirements. Therefore, the research of non-orthogonal multiple access (NOAA) for the fifth generation mobile communication system (5G), which can effectively enhance the capacity of the system, has been paid more and more attention. SCMA (Sparse Code Multiple Access) and NOMA (Non-orthogonal MultipleAccess), two most representative non-orthogonal multiple access technologies, are simulated in this paper. Based on the simulation results, the effects of interference and power allocation on the performance of the system are analyzed. Firstly, the paper briefly analyzes the SCMA system model and key technologies, and then introduces the SCMA system simulation platform, including the basic parameters of the platform and the platform simulation flow chart. In particular, the platform-based simulation of SCMA non-orthogonal multiple access technology is discussed. Based on the platform, two kinds of systems, OFDMA (Orthogonal Frequency Division Multiplexing Access) and SCMA, are simulated in this paper. The simulation results show that SCMA has a better performance than OFDMA in terms of the number of access users and the throughput of the system. Furthermore, the effect of adaptive modulation coding on the performance of SCMA system and the influence of intra-cell interference on the useful signal are analyzed. Then, based on the NOMA system model, the research on the fairness between users in NOMA system is carried out. Based on Lagrange multiplier method, cell fairness index (cell fairness index,CFI) and 伪 utility function, the power allocation optimization algorithm under fairness constraints is simulated, and the number of users in different cells is obtained. Under different cell radius and different transmit power, the change curves of cell fairness index, spectrum efficiency and energy efficiency of the cell are obtained, and the conclusions are instructive for the design of NOMA system.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN929.5

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