在車用網路下基於IEEE 802.11 的車間通訊和基地台與車間通訊是智慧運輸系統的新興科技。伴隨著這些科技，車輛可以透過開放式的存取點來利用基礎建設有效地與其他車輛通訊。這可以避免長時間無線任意的路徑，並減輕無線頻寬壅塞的問題。在本文中提出了基礎建設佈建的策略，用來幫助資料傳輸到任何的車輛。有了這些在路口的基礎建設幫助之下，封包可以透過有線網路傳到目的地附近的基地台。這不僅可以減少資料傳輸的延遲，也可以增加資料傳輸率。模擬結果顯示在高車輛密度與低封包產生率的情況下IAR可以達到與RAR相同的效能，即使只使用了58%的基礎建設，亦即效益比上IAR 表現地比RAR 來得優異。另外相較其他路由協定也有較好的表現，尤其是在網路經常中斷的較低密度車用隨意網路當中。

Inter-Vehicle Communications (IVC) and Roadside-to-Vehicle Communications (RVC) in vehicular networks based on IEEE 802.11 are emerging technologies for Intelligence Transportation System (ITS). With them vehicles can opportunistically exploit infrastructures through open Access Points (APs) to efficiently communicate with other vehicles. This is to avoid long wireless ad hoc paths, and to alleviate congestion in the wireless bandwidth. In this thesis, the strategy of infrastructure deployment which can use fewer infrastructures to cover all intersections helping relay data to every road segment is introduced. With the assistance of infrastructures at intersections, the packets can be transmitted to the infrastructures nearby the destination through the wired network. This not only reduces the overall data delivery delay but also increases the data delivery ratio. The simulation results show that IAR can achieve the same performance though the infrastructures which is much fewer than RAR in the condition of high vehicle density and low packet rate, which means the ratio of benefit to cost in IAR is better than RAR. Besides, IAR outperforms the other protocols, especially under lower vehicle density where the network is frequently partitioned.

[1] 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, pp. 59-68, Sept. 2007.
[2] Y. Peng, Z. Abichar, and J. Chang, “Roadside-Aided Routing (RAR) in Vehicular Networks,” in IEEE International Conference on Communications, vol. 8, pp. 3602-3607, June 2006.
[3] 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 2nd Annual International Workshop on Wireless Internet, vol. 220, Aug. 2006.
[4] 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 1st International MobiSys Workshop on Mobile Opportunistic Networking, pp. 47-51, Jan. 2007.
[5] R. He, H. Rutagemwa, and X. Shen, “Differentiated Reliable Routing in Hybrid Vehicular Ad Hoc Networks,” in IEEE International Conference on Communications, pp. 2353-2358, May 2008.
[6] C. E. Perkins and E. M. Royer, “Ad-hoc On-demand Distance Vector Routing,”Mobile Computing Systems and Applications, pp. 90-100, Feb. 1999.
[7] “NS2 simulator,” http://www.isi.edu/nsnam/ns/, 2009.
[8] “MOVE -MObility model generator for VEhicular networks,” http://www.csie.ncku.edu.tw/ klan/move/index.htm/, 2009.
[9] F. Karnadi, Z. H. Mo, and K.-C. Lan, “Rapid Generation of Realistic Mobility Models for VANET,” in IEEE Wireless Communications and Networking Conference, pp. 2506-2511, Mar. 2007.
[10] “SUMO - Simulation of Urban Mobility,” http://sumo.sourceforge.net/, 2009.
[11] “TraNS - Traffic and Network Simulation Environment,” http://trans.epfl.ch/, 2009.