早期在沒有基地台或存取點的情況下，每個移動節點(Mobile Node)要彼此溝通或傳遞資訊只以其他鄰近的移動節點為跳台的方式傳遞，達到資料傳輸的作用，此特殊傳輸模式的無線網路環境稱之為行動隨意網路(Mobile Ad Hoc Network, MANET)。行動隨意網路的應用，通常運用在例如探險隊、深山救援隊，甚至軍隊中個小隊的通訊方式，皆屬於行動隨意網路的範疇。當行動隨意網路的移動節點從人換成行車時，其特性包括節點移動速度快、拓樸變化性高、連線維持困難等特質，此特殊型態網路稱之為車載網路(Vehicular Ad Hoc Network, VANET)，容易造成網路斷訊和路由錯誤的問題，使得早期車載網路在運用上並無理想與便利的成效，需要另外設計車載網路專用的溝通方式與路由機制設計。

以十字路口為基礎(Intersection Based)的路由機制是近年來車載網路研究的方向主軸，行車在道路上定期將自身蒐集到的環境資訊統整好後透過控制封包(Control Packet)廣播給網路裡的其他行車，提供包括路段連線能力、路段上的行車密度等輔助資訊，讓資料封包(Data Packet)在傳送時，根據這些資訊判斷出一條最合適的路由路徑進行資料傳送。由於車載網路環境變化非常劇烈，即便透過蒐集到的資訊協助判斷仍然容易造成資料封包的傳輸失誤，而傳輸失誤中有個重要的原因，就是協助轉傳的行車離開傳輸範圍。為了有效解決此問題，本論文針這現象提出了一種對環境變化的預判機制來協助判斷，在不需要額外的設備輔助就可以運行，而且也不會更動到原有的控制封包的格式與內容，對網路環境並不會造成額外的負擔的情況下，預先剔除掉一些容易造成傳輸失誤的的傳輸路徑，提升網路傳輸的效率。最後，觀察模擬結果顯示，本論文的機制相較於其他相關的路由機制確實能有效提升網路傳輸的效能。

In the past, each mobile node communicates with each other via neighboring nodes in a wireless environment without base stations or access points. Such a network is called mobile ad hoc network (MANET). Possible applications of MANET can be found in explorer teams, mountain rescue teams, and military fields etc. When mobile nodes are replaced by vehicles, it forms a specific network called vehicular ad hoc network (VANET). VANETs have some intrinsic characteristics, e.g., high node mobility, dynamic topologies, and difficulty in connection maintenance. The problems of frequent network disconnections and routing errors then cause poor performance in early VANETs, necessitating a new dedicated routing protocol.

Recently, the intersection-based routing protocol in which vehicles integrate collected environment information and broadcast to other vehicles via control packets drew attention in VANETs. The integrated information may include road segment connectivity and vehicle density along a road segment etc. to determine an appropriate route for transmission of data packets. Due to frequent topology changes, failure transmissions of data packets occur frequently even if the collected environment information is utilized. Further checking the reason to cause the transmission failure, it is caused by the fact that an assisted vehicle has left that transmission area. To properly tackle such an issue, an environment predicted routing protocol is proposed in this thesis to eliminate some vehicles and routing paths which may bring more transmission failures without extra equipments, changes of control packets, and network overheads. Via simulations, we successfully show the superiority of the proposed routing protocol over the closely related routing protocols in the literature.

[1] C. Suthaputchakun and Z. Sun, “Routing protocol in intervehicle communication systems: a survey,” IEEE Communications Magazine, vol. 49, no. 12, pp. 150–156, Dec. 2011.
[2] V. Vijayalakshmi, M. Sathya, S. Saranya, and C. Selvaroopini, “Survey on
various mechanisms for secure and efficient vanet communication,” Proc. International Conference on Information Communication and Embedded Systems
(ICICES), pp. 1–5, Feb. 2014.
[3] P. Nithya Darisini and N. S. Kumari, “A survey of routing protocols for vanet in urban scenarios,” Proc. International Conference on Pattern Recognition, Informatics and Mobile Engineering (PRIME), pp. 464–467, Feb. 2013.
[4] X. Ma, X. Yin, and K. Trivedi, “A robust broadcast scheme for vanet one-hop emergency services,” Proc. IEEE Vehicular Technology Conference (VTC
Fall), pp. 1–5, Sep. 2011.
[5] G. S. Khekare, “Design of emergency system for intelligent traffic system using vanet,” Proc. International Conference on Information Communication and Embedded Systems (ICICES), pp. 1–7, Feb. 2014.
[6] M. M. Taha and Y. M. Hasan, “Vanet-dsrc protocol for reliable broadcasting of life safety messages,” IEEE International Symposium on Signal Processing and Information Technology, pp. 104–109, Dec. 2007.
[7] S. Bitam, A. Mellouk, and S. Zeadally, “Vanet-cloud: A generic cloud computing model for vehicular ad hoc networks,” IEEE Wireless Communications, vol. 22, no. 1, pp. 96–102, Feb. 2015.
[8] R. Bala and C. R. Krishna, “Performance analysis of topology based routing in a vanet,” Proc. International Conference on Advances in Computing, Communications and Informatics (ICACCI), pp. 2180–2184, Sep. 2014.
[9] J.-L. Lee, D. Kim, L. Fan, and H. J. Chang, “Barrier-coverage for city block monitoring in bandwidth sensitive vehicular adhoc networks,” Proc. International Conference on Mobile Ad-hoc and Sensor Networks (MSN), pp. 80–
87, Dec. 2014.
[10] O. Abedi, R. Berangi, and M. A. Azgomi, “Improving route stability and overhead on aodv routing protocol and make it usable for vanet,” Proc. International Conference on Distributed Computing Systems Workshops (ICDCS),
pp. 464–467, Jun. 2009.
[11] B. Vidhale and S. S. Dorle, “Performance analysis of routing protocols in realistic environment for vehicular ad hoc networks,” Proc. International Conference on Systems Engineering (ICSEng), pp. 267–272, Aug. 2011.
[12] Y. Mingchuan, Y. Liang, G. Qing, et al., “Congestion-aware and hybrid routing protocol for vehicular ad hoc network,” Proc. International Conference on Computer Science and Network Technology (ICCSNT), pp. 349–353, Dec. 2012.
[13] I. D. Chakeres and E. M. Belding-Royer, “Aodv routing protocol implementation design,” Proc. International Conference on Distributed Computing Systems Workshops, pp. 698–703, Mar. 2004.
[14] B. Karp and H.-T. Kung, “Gpsr: Greedy perimeter stateless routing for wireless networks,” Proc. International Conference on Mobile Computing and
Networking, pp. 243–254, Aug. 2000.
[15] H. Noori and B. B. Olyaei, “A novel study on beaconing for vanet-based vehicle to vehicle communication: Probability of beacon delivery in realistic large-scale urban area using 802.11 p,” Proc. International Conference on Smart Communications in Network Technologies (SCNT), vol. 1, pp. 1–6, Jun. 2013.
[16] R. Bala and C. R. Krishna, “Scenario based performance analysis of aodv
and gpsr routing protocols in a vanet,” Proc. International Conference on
Computational Intelligence and Communication Technology (CICT), pp. 432–
437, Feb. 2015.
[17] A. Takano, H. Okada, and K. Mase, “Performance comparison of a positionbased routing protocol for vanet,” Proc. International Conference on Mobile Adhoc and Sensor Systems, pp. 1–6, Oct. 2007.
[18] M. G. de La Fuente and H. Labiod, “Performance analysis of position-based routing approaches in vanets,” Proc. International Conference on Mobile Wireless Communications Networks, pp. 16–20, Sep. 2007.
[19] G. Fenu and M. Nitti, “Strategies to carry and forward packets in vanet,” Communications in Computer and Information Science, pp. 662–674, 2011.
[20] L.-D. Chou, J.-Y. Yang, Y.-C. Hsieh, D.-C. Chang, and C.-F. Tung,
“Intersection-based routing protocol for vanets,” Wireless personal communications, vol. 60, no. 1, pp. 105–124, Mar. 2011.
[21] R. Tavakoli and M. Nabi, “Tiger: A traffic-aware intersection-based geographical routing protocol for urban vanets,” Proc. IEEE Vehicular Technology Conference (VTC Spring), pp. 1–5, Jun. 2013.
[22] S. Sukumaran, L. Ramachandran, and S. R. Sunny, “Intersection based
traffic aware routing in vanet,” Proc. International Conference on Advances
in Computing, Communications and Informatics (ICACCI), pp. 1414–1417,
Aug. 2013.
[23] W. Wang, F. Xie, and M. Chatterjee, “Small-scale and large-scale routing in vehicular ad hoc networks,” IEEE Transactions on Vehicular Technology, vol. 58, no. 9, pp. 5200–5213, Jun. 2009.
[24] N. Brahmi, M. Boussedjra, J. Mouzna, and M. Bayart, “Road connectivitybased routing for vehicular ad hoc networks,” Proc. International Conference on Advanced Technologies for Communications (ATC), pp. 255–259, Oct.2010.
[25] H. Saleet, R. Langar, K. Naik, R. Boutaba, A. Nayak, and N. Goel,
“Intersection-based geographical routing protocol for vanets: A proposal
and analysis,” IEEE Transactions on Vehicular Technology, vol. 60, no. 9,
pp. 4560–4574, Oct. 2011.
[26] J.-J. Chang, Y.-H. Li, W. Liao, and C. Chang, “Intersection-based routing for urban vehicular communications with traffic-light considerations,” IEEE Wireless Communications, vol. 19, no. 1, pp. 82–88, Feb. 2012.
[27] P. K. Sahu, E. Wu, J. Sahoo, and M. Gerla, “Bahg: Back-bone-assisted hop greedy routing for vanet’s city environments,” IEEE Transactions on Intelligent Transportation Systems, vol. 14, no. 1, pp. 199–213, Feb. 2013.
[28] I. Rubin, A. Horng, and C.-Y. Yang, “Lane based backbone synthesis protocols for vehicular ad hoc networks,” Annual Mediterranean on Ad Hoc Networking Workshop, pp. 95–102, Jun. 2014.
[29] Q. Yang, A. Lim, S. Li, J. Fang, and P. Agrawal, “Acar: Adaptive connectivity aware routing for vehicular ad hoc networks in city scenarios,” Mobile Networks and Applications, vol. 15, no. 1, pp. 36–60, Feb. 2010.
[30] M. Slavik and I. Mahgoub, “Spatial distribution and channel quality adaptive protocol for multihop wireless broadcast routing in vanet,” IEEE Transactions on Mobile Intersection-based routing protocol for VANETs, vol. 12, no. 4, pp. 722–734, Feb. 2013.
[31] W. Cha, J. Jeong, J. Kim, and S. Yu, “An adaptive link management for vehicular ad hoc networks,” Proc. International Conference on Wireless Communications and Signal Processing (WCSP), pp. 1–4, Oct. 2010.
[32] J. Nzouonta, N. Rajgure, G. Wang, and C. Borcea, “Vanet routing on city
roads using real-time vehicular traffic information,” IEEE Transactions on Vehicular Technology, vol. 58, no. 7, pp. 3609–3626, Feb. 2009.
[33] “The network simulator - ns-2,” www.isi.edu/nsnam/ns/, 2010.
[34] J. Ai, A. A. Abouzeid, and Z. Ye, “Cross-layer optimal decision policies for spatial diversity forwarding in wireless ad hoc networks,” IEEE International Conference on Mobile Adhoc and Sensor Systems (MASS), pp. 150–159, Oct. 2006.