【作者】 管仲；

【导师】 蔡德林；

【作者基本信息】 安徽大学 ， 通信与信息系统， 2010， 硕士

【摘要】 随着通信技术的发展,无线视频传输技术已广泛应用于工业和社会生活的各个领域.公共安全领域的救援和监控要求在高速移动的环境中实现视频、语音、数据等宽带多媒体业务的实时、同步传输。而无线信道带宽资源有限,干扰因素多,视频信号数据量大,实时性要求高。针对这些问题,本文探讨将COFDM技术用于高速移动条件下无线图像传输的实现方案。文中介绍了COFDM的技术原理、主要优点及存在的不足,重点讨论了基于COFDM技术的图像传输系统的整体设计。COFDM系统是信道编码和OFDM技术的结合,重点介绍了信道编码,包括外编码和内编码,数据交织,包括外交织和内交织,讨论了系统如何通过信道编码来对抗无线信道带来的各种衰落。系统采用结构化设计,根据系统整体要求和指标分配将系统分为多个模块,包括编码模块,数据复用模块,COFDM调制模块,滤波器单元,低噪放单元等。文中描述了各模块单元的功能,并结合具体技术指标给出了各个单元电路的设计。系统在硬件实现后进行了一系列测试和环境试验,进一步验证了系统设计的合理性和可靠性.测试结果表明,系统基本满足了设计要求,实现了在典型城市环境下,在150km/h的移动速度下图像的可靠传输。目前,该系统已广泛应用于指挥,抢险等公共安全领域。更多还原

【Abstract】 With the development of communication technology, wireless video transmission technology has been widely used in industry and in all areas of social life. The rescue and monitoring in the field of Public safety require the transmission of the video, the voice and data in real-time and synchronously. However,there are limited resources and much interfernce in wireless channnels,and heavy traffic and high real-time demand for video signals.Aiming at these problems,this thesis analyzes how COFDM technelogy is used to implement wireless video transmission under the condition of high moving speed.After briefly intruducing COFDM technelogy theories,its major advantages and shortcomings,this thesis focuses on the whole design of COFDM-baced clear video transmission system. The COFDM system is the union of channel coding and the OFDM technology.The article introduced the channel coding and discussed how the system to resist each kind of decline through the channel coding.The system uses the structurization design. According to the system whole request and the target assignmen,the system is divided in to many modules, including the code module, the data multiplying module, the COFDM modulation module, the filter unit, the low noise amplifier unit and so on.The article described various modules unit function and gave each unit electric circuit’s design.After a series of hardware tests and environmental testing, the system further verifies the rationality and feasibility of the design. Test results show that the system basically meets the design requirements, the image can transport at the speed of 150km/h reliablely in a typical urban environment. Currently, the system has been widely used in command, rescue and other public safety fields.更多还原