Turbo码在数字视频广播中的应用

【作者】 闫东；

【导师】 姜威；

【作者基本信息】 山东大学 ， 通信与信息系统， 2006， 硕士

【摘要】 DTTB(数字电视地面广播)是现有数字电视广播方式中的一种，它的传输是通过地面无线进行的，其独具的简单接受和移动接收的能力，能够满足现代信息化社会所要求的“信息到人”的基本需求。并且地面数字广播可以在原普通模拟电视频道内播出完整的高清晰电视节目，使清晰度和声音质量得到大幅改善，能最终实现真正的高清晰度电视。数字电视广播发展十几年来，卫星和有线电缆广播的基本传输体制已确定，而地面广播由于传输环境恶劣，频谱资源有限，应用需求分散，其标准在各国仍有极大的争议，因为目前没有一套标准能解决实际地面传输中的所有问题，因此数字电视地面广播在许多方面都有很大的改进潜力。 DVB-T(Digital Video Broadcasting)是目前国际认可的数字电视地面广播标准之一，也是广播电视业及多国数字地面电视接收测试中评价最高的地面电视广播标准。本文基于COFDM传输方案，主要论述了数字地面广播COFDM传输系统中信道编解码技术，信道编解码技术是COFDM传输系统中非常重要的部分，编解码的性能对整个传输系统影响很大，我们可以通过对各模块电路参数的选择来提高性能，同时也可以将其它优秀的编解码方案用于数字地面广播COFDM传输系统中，将会更大程度地提高系统的性能。本文介绍了COFDM传输原理和数字电视地面广播系统的COFDM实现方案。分析了COFDM传输系统中基于串行级联码的信道编解码性能并进行Matlab仿真。Turbo码自1993年提出后就一直是通信领域的研究热点，而Turbo译码更是研究热点中的热点，本文首先从编码器、译码器和格栅截断方面介绍了Turbo码的原理，并对Turbo码的性能进行了分析，在此基础上，对影响Turbo码性能的几种因素进行了仿真。随后，本文在分析了几种Turbo译码算法的基础上，对它们的性能和复杂度进行了比较。最后在此基础上，提出了用并行级联的Turbo码来替代串行级联码的方案，并通过性能仿真探讨了该方案实施的可行性。更多还原

【Abstract】 DTTB(Digital Television Terrestrial Broadcasting) is one of the present digital television broadcasting modes, whose transmission media is earth. After a decade of intense research and development, the standards of Digital Television Satellite Broadcasting and Digital Television Cable Broadcasting have been confirmed. But the standard of Digital Television Terrestrial Broadcasting is still in disputation, for its transmission environment is rather awful, its spectrum resource is very limited and its service required is disperse, so it is potential to be improved in many aspects.DVB-T (Digital Video Broadcasting) specification is one of the DTTB standards. It has better results in digital television program terrestrial reception test and has good appraisement in digital television broadcasting industry. This paper based on COFDM transmission scheme, expround the encode/decode technology in channel of DVB-T COFDM transmission system,it is very important in DVB-T COFDM transmission system. The performance of encode/decode will have a tremendous influence to the whole transmission system, we can improve performance through the choice to every module circuit parameter, and we can use other outstanding encode/decode schemes too, it will improve the performance of the whole system greater. This paper gives the COFDM transmission principle and DVB-T COFDM scheme. On the basis of theory about channel coding, simulation of the performance on SCCC based with Matlab has been done. Turbo codes have been the hot research area in communication since it was proposed in 1993. Turbo decoding has been paid more attention. The principle of Turbo codes is introduced in the following aspects: encoder, decoder structure and trellis termination. Some performance effect factors are simulated based on the performance analysis. And then, this paper analyses the turbo decoding algorithms from the aspects of performance and complexity. Finally, Turbo coding applied in COFDM is discussed, and its feasibility also tested by lots of performance analysis.更多还原