透過無線傳輸來收看視訊影片成為近年來相當熱門的網路應用之ㄧ，但是無線網路通道環境與多媒體影像資料的特性嚴重導致播放品質下降，然而近年來MIMO系統的發展越來越成熟，大大改善了無線網路的傳輸效果，本論將提出一個視訊封包的排程演算法，應用在MIMO系統上傳送視訊資料。這個排程演算法會同時考慮多路徑狀態，視訊封包的相依特性，選擇適合的錯誤更正碼，重傳機制以及最佳的傳輸路徑。這個演算發主要分成三個階段來發展，第一階段，MIMO系統會先找尋最佳的傳輸路徑。第二階段，排程器會考慮多路徑狀態與封包之間特性，以及系統的傳輸平衡狀態，有效率地決定每一個可能傳送封包的傳送天線與適當的錯誤更正碼。最後會根據頻寬的限制要求以及每個封包的解碼期限，傳送出最佳的封包群組。根據實驗結果與前人提出的方法比較，本方法有較佳的播放品質。

Video streaming over wireless networks becomes a popular network application in recent years, however, characteristics of wireless channel conditions and video data make reliable transmission streaming video over wireless networks still a challenge issue. The mature of wireless MIMO systems can significantly improve the quality wireless video. Hence, the objective of this research is to investigate a rate-distortion optimized framework for downlink of video streams over MIMO wireless systems, which cover antenna selection, FEC rate decision and video packet scheduling. The rate-distortion optimized framework adopts cross-layer design to determine optimal FEC/ARQ mechanism and transmission path. The proposed algorithm can be divided into three stages: (1) MIMO systems find optimal antenna selection based on Hungarian algorithm. (2) The scheduler uses multiple channel conditions, dependency between video packets, and transmission balance to determine appropriate transmit antenna and FEC for each possible transmitted packet. Finally, the scheduler uses a greedy approach to transmit a group of the packets that minimize expected distortion and satisfy rate constraints and deadline constraints. We compare the performance of the proposed algorithm to pervious schemes by computer simulations. The simulation results show that our scheme achieves better performance than others in terms of PSNR.

[1] T. Wiegand, G. J. Sullivan, G. Bjøntegaard, and A. Luthra: “Overview of the H.264/AVC Video Coding Standard”, in IEEE Transactions on Circuits and Systems for Video Technology, vol. 13, pp. 560–576, July 2003.
[2] Paolo Bucciol, Enrico Masala and Juan Carlos De Martin, “Perceptual ARQ for H.264 Video Streaming over 3G Wireless Networks”, Proceedings of IEEE Int. Conf. on Communications (ICC), vol. 3, pp. 1288-1292, June 2004.
[3] M. U. Demircin and Y. Altunbasak, “Finite horizon FEC rate adaptation for real time wireless multimedia,” in IEEE Wireless Communications and Networking Conference, pp. 1770-1775, 2004.
[4] X. Liu and W. Badawy, “A novel Adaptive error control scheme for real-time wireless video streaming,” IEEE Wireless Communication and Networking Conference, pp. 460-463, Aug. 2003.
[5] P. A. Chou and Z. Miao, “Rate-Distortion Optimized Streaming of Packetized Media,” Microsoft Research tech. rep. MSR-TR-2001-35, Feb. 2001.
[6] H. Seferoglu, Y. Altunbasak, O. Gurbuz and O. Ercetin, “Rate Distortion optimized joint ARQ-FEC scheme for real-time wireless multimedia,” IEEE International Conference on Communications, vol. 2, pp. 1190-1194, May 2005.
[7] J. Chakareski and P. A. Chou, “Application layer error-correction coding for rate distortion optimized streaming to wireless clients,” IEEE Transactions on Communications, vol. 52, no. 10, Oct. 2004.
[8] J. Chakareski and B. Girod, “Rate-distortion optimized packet scheduling and routing for media streaming with path diversity” Proceeding of the Data Compression Conference, pp. 203-212, Mar. 2003.
[9] P. Pahalawatta, R. Berry, T. Pappas, and A. Katsaggelos, “Content-aware resource allocation and packet scheduling for video transmission over wireless networks”,. IEEE J. Sel. Areas Commun., vol. 25, no. 4, pp. 749.759, May 2007.
[10] Y.-J. Choi, J. Kim, and S. Bahk, “Downlink Scheduling with Fairness and Optimal Antenna Assignment for MIMO Cellular Systems,” in Proc. IEEE Globecom, vol. 5, pp. 3165-3169, Nov 2004.
[11] D. Song and C. W. Chen, “Scalable H.264/AVC video transmission over MIMO wireless systems with adaptive channel selection based on partial channel information,” IEEE Trans. Circuits Syst. Video Technol., vol. 17, no. 9, pp. 1218–1226, Sep. 2007.
[12] T. Yoo and A. Goldsmith, “On the optimality of multiantenna broadcast scheduling using zero-forcing beamforming,” IEEE J. Select. Areas Commun., vol. 24, pp. 528–541, Mar. 2006.
[13] Bernard Sklar, “Reed-Solomon Codes” Prentic-Hall,2001.
[14] http://iphome.hhi.de/suehring/tml/download/ , JM H.264/AVC Software
[15] Andrea Goldsmith “Wireless Communications”, Cambridge University Press, 2005.
[16] H. Seferoglu, O. Gurbuz, O. Ercetin, Y. Altunbasak, “Rate-distortion based real-time wireless video streaming”, Signal Processing: Image Communications 529–542, 22 (July 2007)