車用隨意網路在近年來受到相當的矚目，其中車對車傳輸是一個重要的應用。車用網路傳輸中，可分為車間通訊和車輛與基地台的通訊。藉由結合有線與無線傳輸，這些基地台可以提供有線的連線提供更有效率的車間傳輸服務。本文提出了以路段做為車輛的位置標記，當車輛切換路段時，會回報基地台所進入的新路段。因為車用隨意網路的特性，車輛只會行使在固定的道路上，利用這個特性，不需要使用非常精確的位置資訊，只要記錄路段訊息以及移動方向就可以有效的完成車間傳輸，因此這篇論文不需要在都市中設置大量的感應器來追蹤車子的絕對位置。這些資訊集中存放於後端資料庫中，當有車輛想要與另一車通訊時，只需將封包傳送到基地台，基地台會依據車輛所在路段資訊可以估計車輛多久會通過該路段，經過計算之後預測車輛的位置，基地台可以研判車輛是否還在可傳送路段附近。如果研判車輛還在該路段附近基地台才會傳送資料，如果判定車輛已經離開該路段又沒有收到新的位置資訊更新則會先把資料存在基地台直到下次收到遠端車輛的位置資料更新。利用依據路段資訊作為資料傳送依據可以適應車用隨意網路可能暫時性無法連結的問題且對於有效的減少使用的基地台數量。模擬結果顯示即使RSLR 使用的基地台數量只有RAR 的四分之一，但在不同的封包產生率、車輛密度與車輛最大速限的情況下 RSLR 都能比RAR 有更高的傳輸成功率。

Vehicular ad hoc networks (VANETs) have received great attention in recent years. Vehicle-to-vehicle routing is an important application in VANETs. Inter-Vehicle Communications (IVC) and Roadside-to-Vehicle Communications (RVC) based on 802.11p are emerging for future Intelligent Transportation System (ITS). The combination of wire and wireless communication can enlarge the scalability and efficiency of the VANETs. This thesis presents a new efficient routing protocol, called Road Segment based Location routing (RSLR), using road segment as each vehicle’s label of position. In order to transmit data between vehicles, location information of each vehicle is needed. Because of the charactoristic of VANETs, the vehicle will move alone each road segment. It does not need accurate location information to delivery data between vehicles. The location updating occurs when a vehicle enter into a different road segment. The packet will be routed to the intersection that vehicle are toward. Using road segment base routing the transmission of data can be more tolerant of temporarily disconnected networks so the number of RSU can be reduced and can provide a location service without using city scale wireless sensor to track all vehicles. Data forwarding between roadside units (RSUs) and onboard units (OBUs) in RSLR uses improved greedy geographic routing
with carry-and-forward mechanism. In order to reduce the contention near RSU. Every medium access behavior is controlled by RSU in its neighborhood. By allocating time periods to the vehicle can reduce the contention near RSU. Simulation results show that RSLR approach can provide a high packet delivery ratio with different vehicle densities,
data packet load and speed limitation of vehicles in VANETs.

[1] H. Hartenstein and K. Laberteaux, “A Tutorial Survey on Vehicular Ad Hoc Networks,”
IEEE Communications Magazine, vol. 46, no. 6, pp. 164–171, June 2008.
[2] E. Royer and C.-K. Toh, “A Review of Current Routing Protocols for Ad Hoc Mobile
Wireless Networks,” IEEE Personal Communications, vol. 6, no. 2, pp. 46–55, Apr.
1999.
[3] 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, May 2008.
[4] M. Jerbi, S.-M. Senouci, T. Rasheed, and Y. Ghamri-Doudane, “Towards Efficient
Geographic Routing in Urban Vehicular Networks,” IEEE Transactions on Vehicular
Technology, vol. 58, no. 9, pp. 5048–5059, Nov. 2009.
[5] Y. Ding, C. Wang, and L. Xiao, “A Static-Node Assisted Adaptive Routing Protocol
in Vehicular Networks,” in Proceedings of the ACM International Workshop on
Vehicular Ad Hoc Networks, Sept. 2007, pp. 59–68.
[6] Y. Peng, Z. Abichar, and J. Chang, “Roadside-Aided Routing (RAR) in Vehicular
Networks,” in Proceedings of the IEEE International Conference on Communications,
June 2006, pp. 3602–3607.
[7] M. Gerla, B. Zhou, Y.-Z. Lee, F. Soldo, U. Lee, and G. Marfia, “Vehicular Grid
Communications: the Role of the Internet Infrastructure,” in Proceedings of the
Annual International Workshop on Wireless Internet, Aug. 2006, pp. 112–120.
[8] G. Marfia, G. Pau, E. De Sena, E. Giordano, and M. Gerla, “Evaluating Vehicle
Network Strategies for Downtown Portland: Opportunistic Infrastructure and the
Importance of Realistic Mobility Models,” in Proceedings of the International MobiSys
Workshop on Mobile Opportunistic Networking, Jan. 2007, pp. 47–51.
[9] R. He, H. Rutagemwa, and X. Shen, “Differentiated Reliable Routing in Hybrid
Vehicular Ad Hoc Networks,” in Proceedings of the IEEE International Conference
on Communications, May 2008, pp. 2353–2358.
[10] Y.-S. Wang and K.-F. Ssu, “An Infrastructure-Assisted Routing Protocol in Vehicular
Ad Hoc Networks,” Master’s thesis, Institute of Computer and Communication
Engineering, National Cheng Kung University, 2009.
[11] H. Zhu, M. Li, Y. Zhu, and L. Ni, “HERO: Online Real-Time Vehicle Tracking,”
IEEE Transactions on Parallel and Distributed Systems, vol. 20, no. 5, pp. 740–752,
May 2009.
[12] “The CitySense Sensor Network Project.” http://www.citysense.net/, 2010.
[13] V. Naumov and T. Gross, “Connectivity-Aware Routing (CAR) in Vehicular Ad
hoc Networks,” in Proceedings of the IEEE International Conference on Computer
Communications, May 2007, pp. 1919–1927.
[14] C. E. Perkins and E. M. Royer, “Ad-Hoc On-Demand Distance Vector Routing,”
in Proceedings of the IEEE Mobile Computing Systems and Applications, Feb. 1999,
pp. 90–100.
[15] B. Karp and H. T. Kung, “GPSR: Greedy Perimeter Stateless Routing for Wireless
Networks,” in Proceedings of the Annual International Conference on Mobile
Computing and Networking, Aug. 2000, pp. 243–254.
[16] A. Skordylis and N. Trigoni, “Delay-Bounded Routing in Vehicular Ad-Hoc Networks,”
in Proceedings of the ACM International Symposium on Mobile Ad Hoc
Networking and Computing, Mar. 2008, pp. 341–350.
[17] Y. Sun, X. Lin, R. Lu, X. Shen, and J. Su, “Roadside Units Deployment for Efficient
Short-time Certificate Updating in VANETs,” in Proceedings of the IEEE
International Conference on Communications, May 2010.
[18] “The Network Simulator – ns-2,” http://www.isi.edu/nsnam/ns/, 2010.
[19] “MOVE - Mobility Model Generator for Vehicular Networks,”
http://www.csie.ncku.edu.tw/»klan/move/index.htm/, 2010.
[20] F. K. Karnadi, Z. H. Mo, and K.-C. Lan, “Rapid Generation of Realistic Mobility
Models for VANET,” in Proceedings of the IEEE Wireless Communications and
Networking Conference, Mar. 2007, pp. 2506–2511.
[21] “SUMO - Simulation of Urban Mobility,” http://sumo.sourceforge.net/, 2010.