基于Walsh序列的云传输广播网的扩频编码  

Spread spectrum coding in a cloud-transmission broadcasting network based on Walsh sequences

作　　者：郝博[1] 王军[1] 王昭诚[1] 

机构地区：[1]清华大学电子工程系清华信息科学与技术国家实验室,北京数字电视国家工程实验室,北京100084

出　　处：《清华大学学报（自然科学版）》2014年第4期413-418,共6页Journal of Tsinghua University(Science and Technology)

基　　金：国家自然科学基金资助项目(61271266);国家"八六三"高技术项目(2012AA011704)

摘　　要：在宽带地面数字广播领域,单频网(single frequency network,SFN)由于具有更高的频谱效率而逐渐替代多频网(multi-frequency network,MFN)成为实际系统布网的首选。但随着移动业务的增长、城市楼宇环境的日趋复杂,传统SFN内容单一、交叠区域信号衰减剧烈的弊端也限制着它的进一步应用。新近提出的云传输SFN由于简单的组网规范、灵活的传输体制以及更高的频率复用率而引起广泛的重视。云传输网络负的信号接收门限保证了两基站重叠区域强回波信道下系统的性能。该文针对云传输体制部署时面临的多基站重叠的挑战,提出一种基于Walsh序列扩频的编码方案,并分析了交叠区域以及叠加多业务后的系统性能,仿真表明:该方案在抗多径和多业务传输方面符合云传输广播网的组网要求,并有实现简单、兼容性好的特点,可同时满足下一代数字广播网高清传输与支持移动的需求,具有良好的应用前景。Single frequency networks （SFN） have gradually replaced multi-frequency networks （MFN） for broadband digital terrestrial broadcasting due to their higher spectral efficiency. However, the growth of mobile services and the complexity of city building environments limit single frequency content with severe attenuation within the overlap region. Recently the cloud-transmission broadcast networks have attracted much attention because of their simple networking specifications, flexible transmission systems and higher reuse frequency. The negative signal receive threshold of cloud transmission networks ensures system performance in the overlap region between two base stations for a strong echo channel. This study focuses on the challenge of the overlap region between multiple base stations for eloud transmission systems with a spread speetrum coding scheme based on Walsh sequences. Simulations of the system performance in the overlap region as well as multi-service superposition show that the cloud transmission broadcasting network scheme has improved anti muhipath fading and multi-service transmission. The scheme is easy to implement and compatible with other broadcasting protocols, which allows it to meet the requirement of high-definition transmissions and mobile support of the next generation digital broadcasting networks.

关 键 词：单频网 云传输 多业务 扩频 

分 类 号：TN945.4[电子电信—信号与信息处理]