高移动性无线通信中的编码调制系统性能研究

发布时间：2018-02-02 16:23

本文关键词： 高速移动列车均衡编码调制系统 Turbo码低密度奇偶校验码　出处：《西安电子科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：信道编码是提高信息传输的可靠技术,在通信系统中充当着重要的角色。在高铁日益普及的今天,对高移动环境下的高可靠性、高谱效率通信技术的研究将有助于给高速移动列车上的乘客提供更好的通信服务质量。本文根据适用于高速移动列车通信的信道模型,主要研究高移动性环境下编码调制系统的性能。在高斯信道下,Turbo码、二元/多元LDPC码的都具有十分有益的性能,采用OFDM技术可以有效抵抗多径衰落对通信系统所带来的影响,因此,对于高移动环境下的通信系统,找到基于OFDM传输下在快速变化信道中性能良好的信道编码技术显得至关重要。本文对一种非平稳基于几何随机模型的高移动信道的各统计特性进行了仿真与分析。接着,研究了OFDM系统中适用于快速变化信道的信道估计技术与信道均衡技术,对它们的特点、计算复杂度等进行了详细的介绍与对比。在此基础上,本文给出了高移动性环境下,基于OFDM技术的编码调制系统的结构框图与仿真流程图,重点对Turbo码、二元LDPC码和多元LDPC码分别结合QPSK、16QAM和64QAM所组成的编码调制系统在快变信道下的性能进行了仿真分析。实际结果表明,对于360km/h及以上的列车移动速度,限于均衡能力有限,64QAM的高阶数调制已经不再适用;在各种编码方式中,相比于Turbo码与二元LDPC码,多元LDPC码在列车高速运行的信道状况下的性能具有明显的优势,是5G高移动通信系统强有力的一种备选编码方案。
[Abstract]:Channel coding is a reliable technology to improve the transmission of information, which plays an important role in the communication system. The research of high spectral efficiency communication technology will help to provide better communication quality of service for passengers on high-speed mobile train. This paper is based on the channel model suitable for high-speed mobile train communication. This paper mainly studies the performance of coded modulation system in high mobility environment. In Gao Si channel, the binary / multivariate LDPC codes have very beneficial performance. OFDM technology can effectively resist the impact of multipath fading on the communication system, therefore, for the communication system in high mobile environment. It is very important to find a channel coding technique with good performance in fast changing channel based on OFDM transmission. In this paper, the statistical characteristics of a non-stationary high mobile channel based on geometric random model are simulated. And analysis. Then. The channel estimation technology and channel equalization technique suitable for fast changing channel in OFDM system are studied. Their characteristics, computational complexity and so on are introduced and compared in detail. In this paper, the structure block diagram and simulation flow chart of the coded modulation system based on OFDM technology are given under the environment of high mobility. The emphasis is on the Turbo code. The performance of the coded modulation system composed of binary LDPC code and multivariate LDPC code combined with QPSKN 16QAM and 64QAM is simulated and analyzed in fast variable channel. For 360 km / h and above, the high order modulation with limited equalization capacity is no longer applicable. Compared with Turbo codes and binary LDPC codes, the performance of multivariate LDPC codes in high-speed train running channel has obvious advantages. It is a powerful alternative coding scheme for 5 G high mobile communication system.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN911.22

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