近年來，道路上車輛數量快速增長，增加了對行動通訊的需求，故有文獻
提出車載隨意網路網絡(vehicular ad hoc network)的新型網絡架構。其具有
提高車輛行駛在道路上的交通效率以及便利性，並且能夠提供駕駛一個更安
全的行車環境。然而，車載隨意網路網絡的要求不僅要符合高變化的拓樸以
及兼顧穩定度，更要兼顧延遲時間、網路頻寬、跟網路負擔…等。因此，如
何在車載網路建立良好的路由且兼顧通訊品質，且提供駕駛一個便利且安全
的行車環境，便是需要深究的主題。迄今，絕大多數的相關研究都集中在路
由協議領域，因為車載隨意網路的路由協議具有極高的挑戰性。車輛行駛快
速，且網路拓撲變化頻繁，更有現實行駛中車輛的間移動性可能導致車輛位
置識別的不正確，以至於傳輸品質不良，導致封包遺失或是傳輸時間延遲增
加。而該如何解決上述問題，便是此本篇論文強調的重點。
本篇論文提出一個新的路由協議，稱enhanced greedy premier stateless
routing protocols (E-GPSR)，此路由是改善 Brad Karp 所提出的 GPSR 的協
議轉發機制，用速率以及調整Hello封包格式，並且用獲得的資訊去預測鄰居
車輛的位置，進而選出最佳的中繼車輛。並且透過實際的城市街景圖比較 E
GPSR 與原本 GPSR 以及二種不同的路由協議，其中路由協議包含著名的 mobile
ad-hoc network (MANET) 中的路由 on demand ad hoc routing (AODV)及
destination sequenced distance vector routing (DSDV)。
本篇論文將與 AODV、GPSR 和 DSDV 相比，E-GPSR 的封包傳遞率平均高於
GPSR 20%，略高於 AODV 以及 DSDV 2.11%。在延遲時間上，E-GPSR 減少 GPSR
約 8%的時間，而和 AODV 相比則平均減少 11.6%。在平均吞吐量上，E-GPSR 高
於 GPSR 30% ，而 E-GPSR 和 AODV 相比，則略高於 AODV 14%。最後，在路由封
包數目方面，E-GPSR 相較於 GPSR 減少了 26 % 的路由封包數目。

In recent years, rapid growth of vehicles on the road has increased demands for mobile-communication. Thus, a new kind ad-hoc network among vehicles has been proposed and it is called vehicular ad-hoc network (VANET). It has strong potential to improve the efficiency and convenience of traffic, and it can provide a safer driving. However, routing in VANETs is challenging. It is not only because of the high-speed movements which results in frequent network topology changes, but also the unstable scalability which may cause loss of the packets and increase the transmission delay time. Moreover, the mobility in real vehicle scenario may cause inaccuracy in the identification of vehicle’s position. Therefore, how to establish a robust path with stable communication quality is main purpose. This thesis proposes a new routing protocol, called enhanced greedy premier stateless routing protocols (E-GPSR), which improves the GPSR proposed by Brad Karp. It obtains the location and velocity to predict the future location of neighboring vehicles by periodically receiving hello packet and using the information to choose the best relay vehicle. Compared E-GPSR to well-known mobile ad hoc routing protocol (MANET) including on demand ad hoc routing (AODV) and destination sequenced distance vector routing (DSDV). When it comes to packet delivery ratio, E-GPSR improves GPSR by 20%, and E-GPSR is better than AODV and DSDV by 2.11%. In terms of delay time, E-GPSR reduces original GPSR about 8% and it is better AODV by 11.6%. And when it comes to throughput, E-GPSR is 30% higher than GPSR, it is higher than AODV 14%, and it is six times better than DSDV. Finally, in the case of routing overheads, E-GPSR reduces original GPSR by 26%.

[1] Duc Ngoc Minh Dang, Hanh Ngoc Dang, Cuong The Do, Choong Seon Hong "An Enhanced Multi-channel MAC for Vehicular Ad Hoc Networks," 2013 IEEE Wireless Communications and Networking Conference (WCNC).

[2] Harding, J., Powell, G., R., Yoon, R., Fikentscher, J., Doyle, C., Sade, D., Lukuc, M., Simons, J., & Wang, J. (2014, August), "Vehicle-to-vehicle communications: Readiness of V2V technology for application." (Report No. DOT HS 812 014). Washington, DC: National Highway Traffic Safety Administration.

[3] Fan Li , Yu Wang ,"Routing in vehicular ad hoc networks: A survey" IEEE Vehicular Technology Magazine ( Volume: 2, Issue: 2, June 2007 ).

[4] Ian Ku, You Lu, Mario Gerla, Rafael L. Gomes, Francesco Ongaro and Eduardo Cerqueira, In Software-Defined VANET Communications - "Towards softwaredefined VANET: Architecture and services" 2014 13th Annual Mediterranean Ad Hoc Networking Workshop (MED-HOC-NET).

[5] J. Harri, F. Filali, C. Bonnet, "Mobility models for vehicular ad hoc networks: a survey and taxonomy", IEEE Communications Surveys and Tutorials, vol. 11, no. 4, pp. 19-41, 2009.

[6] C. Pathak, A. Shrivastava and A. Jain, "Ad-hoc on demand distance vector routing protocol using Dijkastra's algorithm (AODV-D) for high throughput in VANET (Vehicular Ad-hoc Network)," 2016 11th International Conference on Industrial and Information Systems (ICIIS), Roorkee, 2016, pp. 355-359.

40
[7] B. Hamid and E. N. E. Mokhtar, "Performance analysis of the Vehicular Ad hoc Networks (VANET) routing protocols AODV, DSDV and OLSR," 2015 5th International Conference on Information & Communication Technology and Accessibility (ICTA), Marrakech, 2015, pp. 1-6.

[8] R. Anggoro, M. Husni and R. Bastian, "Source route implementation using intersection node on GPSR protocol to increase VANET's data transmission reliability," 2017 International Conference on Advanced Mechatronics, Intelligent Manufacture, and Industrial Automation (ICAMIMIA), Surabaya, 2017.

[9] F. Bai and H. Krishnan, "Reliability Analysis of DSRC Wireless Communication for Vehicle Safety Applications," in Intelligent Transportation Systems Conference, 2006. ITSC '06. IEEE, Toronto, Ont., Sept. 2006.

[10] V. K. AryaMol and S. Sharma, "A hybrid approach for intelligent communication and performance analysis over DSRC VANET," 2017 International Conference on Intelligent Sustainable Systems (ICISS), Palladam, 2017.

[11] M. Wang, Y. Zhang, C. Li, X. Wang and L. Zhu, "A survey on intersectionbased routing protocols in city scenario of VANETs," 2014 International Conference on Connected Vehicles and Expo (ICCVE), Vienna, 2014, pp. 821-826.

[12] Lichuan Liu , Zhigang Wang , Wern-Kueir Jehng, "A geographic source routing protocol for traffic sensing in urban environment". 2008 IEEE International Conference on Automation Science and Engineering.

[13] Mengkun Li, Huan Li , and Huiying , Xiangjie Kong, Bin Feng, Tanggao Nong, Shijian Gao." An Improved GPSR Protocol Based on Stratification of Traffic Density". 2017 IEEE International Conference on Information and Automation (ICIA).

41
[14] C. Lochert, H. Hartenstein, J. Tian, H. Fussler, D. Hermann and M. Mauve, "A routing strategy for vehicular ad hoc networks in city environments," IEEE IV2003 Intelligent Vehicles Symposium. Proceedings (Cat. No.03TH8683), 2003.

[15] The Network Simulator - ns-2. http://www.isi.edu/nsnam/ns/.

[16] D. Krajzewicz, J. Erdmann, M. Behrisch and L. Bieker, "Recent Development and Applications of SUMO - Simulation of Urban Mobility," International Journal on Advances in Systems and Measurements, vol. 5, no. 3&4, pp. 128-138, 2012.

[17] https://www.openstreetmap.org/#map=8/23.611/120.768

[18] N. Ababneh and H. Labiod, "A performance analysis of VANETs routing protocols using different mobility models," 2010 IEEE International Conference on Wireless Communications, Networking and Information Security, Beijing, China, 2010, pp. 498-502