| |
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。
|
| 关键词 ：单频网,云传输,多业务,扩频 |
Abstract：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 cloud transmission systems with a spread spectrum 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-multipath 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.
|
| Key words：single frequency networkscloud-transmissionmulti-servicespread spectrum |
| 收稿日期: 2014-01-14 出版日期: 2015-04-16 |
| 基金资助:国家自然科学基金资助项目 (61271266);国家 “八六三” 高技术项目(2012AA011704) |
| [1] | Dai L, Wang Z, Yang Z. Next-generation digital television terrestrial broadcasting systems: key technologies and research trends [J]. IEEE Communications Magazine, 2012, 50(6): 150-158. |
| [2] | Wu Y, Rong B, Salehian K, et al.Cloud transmission: a new spectrum-reuse friendly digital terrestrial broadcasting transmission system[J]. IEEE Trans. on Broadcasting, 2012, 58(3): 329-337. |
| [3] | DVB Document 302 755. Frame Structure Channel Coding and Modulation for a Second Generation Digital Terrestrial Television Broadcasting System (DVB-T2)[S]. Europe: ETSI Std., 2012. |
| [4] | GB 20600-2006. 数字电视地面广播传输系统帧结构、信道编码和调制 20600-2006. 数字电视地面广播传输系统帧结构、信道编码和调制[S]. 中国: 全国广播电视标准化委员会, 2006. GB 20600-2006. Frame Structure, Channel Coding and Modulation of Digital Television Terrestrial Broadcasting System 20600-2006. Frame Structure, Channel Coding and Modulation of Digital Television Terrestrial Broadcasting System[S]. China: National Television Standards Committee, 2006. (in Chinese) |
| [5] | Montalban J, Rong B, Park S, et al. Cloud transmission: system simulation and performance analysis [C]// IEEE International Symposium on Broadband Multimedia Systems and Broadcasting (BMSB). London, UK: IEEE Press, 2013: 1-5. |
| [6] | Proakis J. Digital Communications[M]. 4th ED. Ohio, USA: McGraw-Hill, 2001. |
| [7] | Hara S, Prasad R. Design and performance of multicarrier CDMA system in frequency-selective Rayleigh fading channels[J]. IEEE Trans. on Vehicular Technology, 1999, 48(5): 1584-1595. |
| [8] | 郝博, 王军, 王昭诚. OFDM系统中基于序列组间距离传输信令信息[J]. 清华大学学报(自然科学版), 2013, 53(7): 972-976. HAO Bo, WANG Jun, WANG Zhaocheng. Signalling transmission based on the distances between training sequences for OFDM systems[J]. J Tsinghua Univ (Sci and Tech), 2013, 53(7): 972-976. (in Chinese) |
| [9] | Appe1 K, Haken W. Every planar map is four colorable: Part 1, discharging[J]. Illinois Journal of Mathemathics, 1977, 21(3): 429-490. |
| [10] | Montalban J, Rong B, Wu Y, et al.Cloud transmission frequency domain cancellation [C]// IEEE International Symposium on Broadband Multimedia Systems and Broadcasting (BMSB). London, UK: IEEE Press, 2013: 1-4. |
),王昭诚
