具天線分集之DVB-T基頻接收機系統設計

歐規數位電視地面廣播(DVB-T)採用正交分頻多工(OFDM)的技術，它在無線通道的傳輸下具有高速率傳輸、高頻譜使用效率以及抵抗多重路徑衰減等優異特性。DVB-T系統擁有比傳統類比電視更高畫質的收視品質並已於2004年正式在台灣開播。　　起初，DVB-T的制定上僅針對固定式與攜帶式接收作設計。然而隨著行動接收需求量的增加，DVB-T在行動接收的環境中便產生了許多侷限。相較於手持行動裝置，由於空間不受限制，將多根天線分集的技術應用於DVB-T系統中來抵抗都卜勒的影響是相當有效率的。在本論文中，我們藉由訊號處理的方式來設計並驗證一套具雙根天線分集技術的DVB-T基頻接收機。我們針對台灣地區所使用的8K傳輸模式，並考慮DVB-T行動接收如安裝在市區環境行駛的車輛上作一研究。系統傳輸的信號格式是依據ETSI EN300 744中制定的規格所設計。再者，我們建立了在接收端為雙根天線下的市區通道模型。另外，在接收機的架構設計上，符元時間同步、載波頻率同步及通道估測，我們皆加以分析以及討論其對於系統所造成的影響，並提出有效的方式來改善。　　由模擬結果顯示，當DVB-T接收端使用雙根天線及最大比值合併的技術下，在市區高速移動的環境中仍可達到良好的收視品質。我們也得知在DVB-T接收端使用雙根天線分集的技術比傳統單根天線能提供更好的接收效能。此外，由模擬結果也驗證了DVB-T 2K模式比8K模式具有更好的行動接收能力。

關鍵字

歐規數位電視地面廣播；正交分頻多工；天線分集；市區通道模型；最大比值合併；符元時間同步；載波頻率同步；通道估測

並列摘要

Digital Video Broadcasting-Terrestrial (DVB-T) adopted Orthogonal Frequency Division Multiplexing (OFDM) technique which exhibits superior characteristics in terms of high-bit-rate transmission, efficiency in spectral utilization and simplicity in combating multi-path fading for broadcasting over wideband wireless channels. The DVB-T system has higher quality (HDTV、SDTV) than the traditional analogue TV and it had been formally started broadcasting in Taiwan on 2004. Primarily, DVB-T was designated to the fixed and portable reception of video services. However, by the increasing demand for mobile reception, there are limitations of the available DVB-T system operated in a mobile environment. As compared with handheld mobile devices, because of space limitations, mobile DVB-T with multi-antenna diversity technique is an effective approach to combat Doppler effects. In this thesis, we design and verify a DVB-T baseband receiver with dual-antenna diversity by signal processing procedure. The investigation major focuses on the 8k transmission mode operated in Taiwan and the mobile DVB-T device employed such as in a vehicle is moving in Typical Urban (TU6) environment. The signal format of the transmission mode is based on the DVB-T standard specified by ETSI. Furthermore, we establish the TU6 channel model with dual-antenna reception. In addition, symbol timing synchronization, carrier frequency synchronization and channel estimation are designed and discussed in the architecture of the receiver.　　　　　　　　　 From the simulation results, it shows that the DVB-T dual-antenna receiver with Maximal Ratio Combining (MRC) can achieve excellent system performance in a mobile environment. We also know that the DVB-T dual-antenna receiver with MRC outperforms the conventional single-antenna receiver. Besides, the simulation results demonstrate that the DVB-T 2k mode exhibits higher mobility than 8k mode as well.

並列關鍵字

Digital Video Broadcasting-Terrestrial (DVB-T) ； Orthogonal Frequency Division Multiplexing (OFDM) ； Antenna diversity ； Typical Urban (TU6) channel model ； Maximal Ratio Combining (MRC) ； Symbol timing synchronization ； Carrier frequency synchronization ； Channel estimation

參考文獻

[11] H. J. Tseng, "DVB-T Mobile Reception Performance Analysis," M.S. thesis, Graduate Institute of Communication Engineering, National Taiwan University, January 2003.

[33] Louis L. Scharf, Statistical Signal Processing, Addison-Wesley, 1991.

[04] U. Ladebusch , C. A. Liss, "Terrestrial DVB (DVB-T): A Broadcast Technology for Stationary Portable and Mobile Use," Proc. IEEE vol. 94, no. 1, pp. 183-193, Jan. 2006.

[09] A. Dammann and S. Kaiser, "Transmit/Receive Antenna Diversity Techniques for OFDM Systems," European Transactions on Telecommunications, vol. 13, no.5, pp. 531-538, September/October 2002.

[16] S .R .Saunders , Antennas and Propagation for Wireless Communication System, John Wiley & Sons, 1999.

國際替代計量

具天線分集之DVB-T基頻接收機系統設計

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