窄带COFDM系统的同步与信道估计研究及硬件实现

【作者】 程辉；

【导师】 钱光弟；

【作者基本信息】 电子科技大学 ， 控制理论与控制工程， 2007， 硕士

【摘要】 数字电视地面广播移动传输技术是融合数字电视、纠错编码、数字信号处理、计算机技术、超大规模集成电路、无线通信等高新技术成果而综合发展起来的一项前沿技术。地面移动传输的环境比较复杂,频谱资源有限并且用户比较分散,所以数字电视地面广播尚无统一的国际标准,这一领域还有很大的研发潜力。随着MPEG-4 AVC标准的提出,研究和开发与H.264/MPEG-4 AVC相匹配的窄带数字视频地面移动传输系统具有十分重要的意义。本项目研究了窄带数字视频地面移动传输系统的基本原理及其在片上系统(SOC, System On Chip)上的具体实现。该项目在设计过程中采用了MPEG-4 AVC信源编码标准、窄带编码调制、最新数字上变频器(DUC)和数字下变频器(DDC)分集接收以及自适应复接等多项先进技术。多项先进技术的运用使系统提高了抗瑞利衰落能力,节省了频率资源,并提高了系统抗突发干扰能力,系统的性能得到显著提高。本窄带编码调制系统填补了我国在移动视频领域的空白。窄带数字视频地面移动传输系统(NBCOFDM)的设计包括信源编码和信道编码两部分,信源编码的目的在于将声音图像等信号转换为可进行信号处理的电信号,信道编码的目的在于保证电信号的正确传输。本论文详细论述了信道编码部分的设计。信道编码的主要任务是编码调制,包括RS码与卷积码级联编解码、正交频分复用技术的IFFT/FFT实现、数字上/下变频的设计、同步恢复及信道估计等关键技术的实现。本文最开始阐述了整个系统的设计方案,接下来详细阐述了无线移动信道下的信道估计及同步恢复技术,并且在Matlab软件仿真的基础上,针对同步及信道估计的信号原理、常用算法及典型算法进行了分析,结合XILINX公司的ISE 6.1i仿真环境,采用FPGA实现了适合本系统的同步及信道估计与均衡算法的硬件设计,并在PCB电路板上得到验证。更多还原

【Abstract】 DTTB (Digital Television Terrestrial Broadcasting) technology is a newly developed technology which has comprehensively combined with many Hi-tech productions such as Digital Television, Coding theory, Digital Signal Processing, Computer Technology, SLSI (Super Large-Scale Integration), Communication Technology and so on. In view of current complex terrestrial transmission environment, limited spectrum resource and dispersed users, there is no undisputed international standard of Digital Television Terrestrial Broadcasting up till now. Therefore, rich research potential has been remained in this field. Researching and designing a narrow band Digital Television Terrestrial Broadcasting transmitting system is significant as soon as MPEG-4 AVC standard was put forward.This project has been focused on the research of basic theory of narrow band Digital Television Broadcasting transmitting system and its practical realization on SOC (system on Chip). The system has taken advantage of many advanced technologies including MPEG-4 AVC theory, narrow band coding and modulation, update digital up transducer, and digital down transducer. The application of so many advanced technologies has improved the ability of Rayleigh fading and saved frequency resource. Meanwhile, the capability of system burst interruption and the comprehensive performance of this system has been obviously upgraded. In final analysis, this narrow band coding and modulation system has injected new energy into the weak field of domestic mobile video.The design of Narrow Band Coded Orthogonal Frequency Multiplexing system contains Signal resource encoding and Channel encoding. The order of Signal resource encoding is transferring image and sound signal to electric signal, and the order of channel encoding is making sure of effectual transmission of electric signal. In this paper, the design of Channel encoding is disserted. It contains RS code、convolutional code、the realization of OFDM with IFFT/FFT、DDC/DUC、Synchronization and channel estimator and so on. The scheme of the system is introduced firstly, and then Synchronization and channel estimator are expatiated. Based on the simulation with Matlab, it expatiates signal theory, common arithmetic and typical arithmetic. In the end, FPGA circuit is designed of Synchronization and channel estimator module in ISE6.1i, and the circuit was checked on PCB board.更多还原