OFDM系统信道估计的实现技术研究
发布时间：2018-08-15 19:18
【摘要】：OFDM系统能够成为当今最有潜力的一种通信系统,是因为其自身固有的抗多径能力强、频带利用率较高,适合高速率的数据通信环境。作为OFDM系统的重要技术之一,信道估计主要完成信号从发射端到接收端的无线信道频率响应的估计。这对于克服无线信道的衰落特性,提高接收机的综合性能有非常重要的意义和研究价值。本文主要研究了OFDM系统的信道估计技术,并依据802.11a的帧结构,设计实现了系统信道估计方案。首先介绍了OFDM系统的工作原理,建立了数据传输的数学模型。依据无线信道的衰落特性,分析了多径衰落和多普勒频移对信号传输过程的影响。其次,讨论了基于OFDM系统的信道估计方法,重点分析了基于导频的信道估计方法。讨论了导频的插入数量和图案,研究了导频位置处的信道估计和数据位置处的插值技术,为后续设计802.11a的信道估计方案提供依据。设计和实现802.11a信道估计方案是本文的重点。依据802.11a的帧结构和导频数量,综合考虑了信道估计性能和实现的可行性,设计了基于长训练序列和导频综合的信道估计方案。对于长训练序列的信道估计,采用基于两个长训练序列的LS估计方法。对于导频的信道估计,采用基于LS准则和线性插值相结合的信道估计方案。最后实现了基于802.11a的OFDM系统的信道估计方案,并对估计模块进行了功能验证和电路验证,以表明了系统信道估计方案的可行性。结合帧检测、载波同步、定时同步等模块进行联调,验证系统接收端的功能。
[Abstract]:OFDM system can become the most potential communication system because of its strong anti-multipath ability, high bandwidth utilization, and suitable for high-speed data communication environment. As one of the most important techniques in OFDM systems, channel estimation mainly completes the estimation of the wireless channel frequency response from the transmitter to the receiver. It is of great significance and research value to overcome the fading characteristic of wireless channel and improve the comprehensive performance of receiver. This paper mainly studies the channel estimation technology of OFDM system, and designs and implements the channel estimation scheme according to the frame structure of 802.11a. Firstly, the working principle of OFDM system is introduced, and the mathematical model of data transmission is established. According to the fading characteristics of wireless channel, the effects of multipath fading and Doppler shift on the signal transmission process are analyzed. Secondly, the channel estimation method based on OFDM system is discussed, and the channel estimation method based on pilot frequency is analyzed. The number and pattern of pilot insertion are discussed, and the channel estimation at pilot position and interpolation technique at data location are studied, which provides the basis for the subsequent design of 802.11a channel estimation scheme. The design and implementation of 802.11a channel estimation scheme is the focus of this paper. According to the frame structure and pilot number of 802.11a, the channel estimation scheme based on long training sequence and pilot synthesis is designed by considering the performance and feasibility of channel estimation. For the channel estimation of long training sequence, LS estimation method based on two long training sequences is adopted. For pilot channel estimation, a channel estimation scheme based on LS criterion and linear interpolation is proposed. Finally, the channel estimation scheme of OFDM system based on 802.11a is implemented, and the function verification and circuit verification of the estimation module are carried out to demonstrate the feasibility of the channel estimation scheme. Combined with frame detection, carrier synchronization, timing synchronization and other modules to verify the functions of the system receiver.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN929.53
本文编号：2185163
[Abstract]:OFDM system can become the most potential communication system because of its strong anti-multipath ability, high bandwidth utilization, and suitable for high-speed data communication environment. As one of the most important techniques in OFDM systems, channel estimation mainly completes the estimation of the wireless channel frequency response from the transmitter to the receiver. It is of great significance and research value to overcome the fading characteristic of wireless channel and improve the comprehensive performance of receiver. This paper mainly studies the channel estimation technology of OFDM system, and designs and implements the channel estimation scheme according to the frame structure of 802.11a. Firstly, the working principle of OFDM system is introduced, and the mathematical model of data transmission is established. According to the fading characteristics of wireless channel, the effects of multipath fading and Doppler shift on the signal transmission process are analyzed. Secondly, the channel estimation method based on OFDM system is discussed, and the channel estimation method based on pilot frequency is analyzed. The number and pattern of pilot insertion are discussed, and the channel estimation at pilot position and interpolation technique at data location are studied, which provides the basis for the subsequent design of 802.11a channel estimation scheme. The design and implementation of 802.11a channel estimation scheme is the focus of this paper. According to the frame structure and pilot number of 802.11a, the channel estimation scheme based on long training sequence and pilot synthesis is designed by considering the performance and feasibility of channel estimation. For the channel estimation of long training sequence, LS estimation method based on two long training sequences is adopted. For pilot channel estimation, a channel estimation scheme based on LS criterion and linear interpolation is proposed. Finally, the channel estimation scheme of OFDM system based on 802.11a is implemented, and the function verification and circuit verification of the estimation module are carried out to demonstrate the feasibility of the channel estimation scheme. Combined with frame detection, carrier synchronization, timing synchronization and other modules to verify the functions of the system receiver.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN929.53
【参考文献】
相关期刊论文 前1条
1 郭士伟;曹雪虹;苏岚;;OFDM系统中基于预编码的时变信道半盲估计方法[J];电力系统通信;2008年03期
，本文编号：2185163
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