在這篇論文當中，我們在一由車用網路及3G/3.5G行動網路所構成之複合式網路下提出一個利用H.264/SVC可調式壓縮編碼技術之多躍點成員協力式視訊多媒體串流服務系統。在這一車隊的成員中，成員彼此互相認識。這車隊可能是由一個家族或者一群朋友，當他們開著車經由相同的路徑前往同一個目的地時所組成。在這篇論文所假設的協力式串流情境中，我們假設在車隊前往目的地的旅程中，有某一車隊成員想要透過其3G/3.5G行動網路去觀看一段影片。然而，由於3G/3.5G行動網路頻寬的限制，此車隊成員在觀看的過程當中並不能擁有較高的觀看影片品質。為了增進串流播放過程中的觀看品質，此稱為要求者(Requester)的車隊成員可以要求其它在同一車隊中稱為幫忙者(Helper)的車隊成員，利用他們的3G/3.5G 介面去幫忙下載串流影片資料並再透過其DSRC車用網路介面透過多躍點的方式傳回其下載之資料給要求者。為了要在車隊成員當中選出適當的車隊成員作為幫忙者，去幫忙下載以及傳回串流影片資料；以及使得要求者的串流播放過程中能擁有順暢的播放品質，我們設計並提出了下列相關機制。(1)一個稱作Bags的多躍點頻寬集結機制來在車隊的成員當中挑選適當的成員來作為幫忙者來幫忙下載及傳回串流影片資料。(2)一個能適應車用網路之動態變化環境的串流工作分配機制來分配串流工作至所選出來的幫忙者上，(3) 以及當串流資料透過車用網路傳回至要求者時，路徑上的中介轉傳點用來決定透過其DSRC網路介面優先轉傳之暫存資料的封包轉傳策略。在最後的部分，我們透過NS2網路模擬環境來分析並探討我們所提的系統並做個結論。

In this study, we proposed a K-hop member-based cooperative video streaming system using H.264/SVC over hybrid networks, i.e. cellular network (3G/3.5G) and DSRC network. Each member in the same group is known with each other, e.g., they may be a family or a group of friends driving their sedans to the same destination along the same path. In the cooperative video streaming scenario, when a member in a vehicle wants to watch video during travelling, he will request video through 3G/3.5G network. However, the limited bandwidth of 3G/3.5G network is not enough to support higher resolution or higher video quality. In order to enhance the quality of video playback, the member called requester in one vehicle can ask other members called helpers of the same group in other vehicles to cooperatively download video through their 3G/3.5G networks and then forward their downloaded video hop by hop to the requester over the DSRC-based ad hoc network. In order to select suitable members as helpers to download and forward the video and make the requester’s playback more smoothly over the DSRC-based ad hoc network, following terms are devised. (1) A K-hop bandwidth aggregation scheme called Bags is devised to select suitable helpers to download and forward their downloaded video data to the requester through the DSRC ad hoc network, (2) a streaming task assignment scheme that has the adaptation capability in the dynamic environment of VANET is designed to schedule the streaming task to each helper, and (3) a packet forwarding scheme, which is adopted by each intermediary node in the forwarding path, that can decide which buffered video data have higher priority to be forwarded to the next forwarder through the limited DSRC network. Finally, we use the NS2 simulation tool to analyze our proposed system and conclude our work.

[1]IEEE Working Group, Standard Specification for Telecommunications and Information Exchange Between Roadside and Vehicle Systems - 5 GHz Band Dedicated Short Range Communications (DSRC) Medium Access Control (MAC) and Physical Layer (PHY) Specifications, ASTM DSR STD E2313-02, 2002.
[2]J. Luo and D. Guo, “Neighbor Discovery in Wireless Ad Hoc Networks based on Group Testing,” Proceedings of the 46th Annual Allerton Conference on Communication, Control, and Computing, pp. 791–797, Sep. 2008.
[3]H.-W. Tsai, C. Chen, C.-C. Shen, R.-H. Jan, and H.-H. Li, “Maintaining Cohesive Fleets via Swarming with Small-World Communications,” Proceedings of IEEE Vehicular Networking Conference (VNC), pp. 1–8, Oct. 2009.
[4]R. Khalili, D. L. Goeckel, D. Towsley, and A. Swami, “Neighbor Discovery with Reception Status Feedback to Transmitters,” Proceedings of the 29th IEEE Conference on Computer Communications (INFOCOM), pp. 2375–2383, Mar. 2010.
[5]T. Taleb, E. Sakhaee, A. Jamalipour, K. Hashimoto, N. Kato, and Y. Nemoto, “A Stable Routing Protocol to Support ITS Services in VANET Networks,” IEEE Transactions on Vehicular Technology, vol. 56, no. 6, pp. 3337–3347, Nov. 2007.
[6]T. Okamura, T. Ideguchi, X. Tian, and T. Okuda, “Traffic Evaluation of Group Communication Mechanism among Vehicles,” Proceedings of the 4th International Conference on Computer Sciences and Convergence Information Technology (ICCIT), pp. 223–226, Nov. 2009.
[7]R. Zoican and D. Galatchi, “Analysis and simulation of a Predictable Routing Protocol for VANETs,” Proceedings of the 9th International Symposium on Electronics and Telecommunications (ISETC), pp. 153–156, Nov. 2010.
[8]A. Nandan, S. Das, G. Pau, M. Gerla, and M.Y. Sanadidi, "Co-operative Downloading in Vehicular Ad-hoc Wireless Networks," Proceedings of the 2nd Annual Conference on Wireless On-demand Network Systems and Services (WONS'05), pp.32-41, 2005.
[9]Y. Liu and M. Hefeeda, "Video Streaming over Cooperative Wireless Networks," Proceedings of the 1st annual ACM SIGMM conference on Multimedia systems, pp. 99-110, 2010.
[10]G. Ananthanarayanan, V. Padmanabhan, C. Thekkath, and L. Ravindranath, “Collaborative Downloading for Multi-homed Wireless Devices,” Proceedings of the 8th IEEE Workshop on Mobile Computing Systems and Applications (HotMobile), pp. 79–84, Mar. 2007.
[11]M.-F. Leung and S.-H. G. Chan, “Broadcast-Based Peer-to-Peer Collaborative Video Streaming Among Mobiles,” IEEE Transactions on Broadcasting, vol. 53, no. 1, pp. 350–361, Mar. 2007.
[12]D. Fan, V. Le, Z. Feng, Z. Hu, and X. Wang, “Adaptive Joint Session Scheduling for Multimedia Services in Heterogeneous Wireless Networks,” Proceedings of the 70th IEEE Vehicular Technology Conference (VTC), pp. 1–5, Sep. 2009.
[13]M. Y. Hsieh, Y. M. Huang, and T. C. Chiang, "Transmission of layered video streaming via multi-path on ad hoc networks," Multimedia Tools and Applications, Vol, 34, No, 2, pp. 155-177, 2007.
[14]M. F. Tsai, N. Chilamkurti, J. H. Park, and C. K. Shieh, "Multi-path transmission control scheme combining bandwidth aggregation and packet scheduling for real-time streaming in multi-path environment," Institution of Engineering and Technology Communications, Vol.4, No.8, pp.937-945, 2010.
[15]K. Rojviboonchai, Y. Fan, Z. Qian, H. Aida, and W. Zhu, "AMTP: a multipath multimedia streaming protocol for mobile ad hoc networks," Proceedings of IEEE International Conference on Communications, pp. 1246- 1250, 2005.
[16]M. Lindeberg, S. Kristiansen, T. Plagemann and V. Goebel, "Challenges and techniques for video streaming over mobile ad hoc networks, " Multimedia Systems, Vol. 17, No. 1, pp. 51-82, 2009.
[17]J. Zhao and G. Cao, "VADD: Vehicle-Assisted Data Delivery in Vehicular Ad Hoc Networks," IEEE Transactions on Vehicular Technology, Vol.57, No.3, pp.1910-1922, 2008.
[18]I. Leontiadis and C. Mascolo, "GeOpps: Geographical Opportunistic Routing for Vehicular Networks," Proceeding of IEEE International Symposium on World of Wireless, Mobile and Multimedia Networks, pp. 1-6, 2007.
[19]K. Chebrolu and R. Rao, "Bandwidth aggregation for real-time applications in heterogeneous wireless networks," IEEE Transactions on Mobile Computing, Vol. 5, No. 4, pp. 388–403, April 2006.
[20]D. Y. Zhu, M. W. Mutka, and Z. W. Cen, "QoS aware wireless bandwidth aggregation (QAWBA) by integrating cellular and ad-hoc networks," Proceedings of the 1st International Conference on Quality of Service in Heterogeneous Wired/Wireless Networks, pp. 156-163, Oct. 2004.
[21]P. Sharma, S. J. Lee, J. Brassil, and K. Shin, "Handheld routers: intelligent bandwidth aggregation for mobile collaborative communities," Proceedings of the 1st International Conference on Broadband Networks, pp. 537-547, Oct. 2004.
[22]S.k. Kwon, A. Tamhankar, K.R. Rao, “Overview of H.264/MPEG-4 part 10”, Journal of Visual Communication and Image Representation, vol. 17, no. 2, pp. 186-216, 2006.
[23]T. Wiegand, G.J. Sullivan, G. Bjontegaard, A. Luthra, "Overview of the H.264/AVC video coding standard," IEEE Transactions on Circuits and Systems for Video Technology, vol.13, no.7, pp.560-576, 2003.
[24]G. Bianchi, "Performance analysis of the IEEE 802.11 distributed coordination function," IEEE Journal on Selected Areas in Communications, Vol.18, No.3, pp.535-547, 2000.
[25]C. Han, M. Dianati, R. Tafazolli, R. Kernchen , “Throughput Analysis of the IEEE 802.11p Enhanced Distributed Channel Access Function in Vehicular Environment, ” Proceedings of the 72nd IEEE Conference on Vehicular Technology, pp.1-5, 6-9, Sept. 2010.