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  • 學位論文

車載網路路由機制之改進

On Advancing Routing Protocols in Vehicular Ad-hoc Networks

指導教授 : 莊博任

摘要


在這個資訊爆炸的時代,隨著行動隨意網路架構出現之後,首先便是承襲舊有有線網路架構,需要整個拓樸資訊的之基於拓撲(Topology-based)的路由協定,由於這類的協定是針對有線網路的架構設計的,所以當節點要傳送封包時,必須仰賴是先建立好的路徑來幫助傳送資料封包,這導致在傳送資料之前必須先耗費大量的控制封包來建立路徑。 由於現今的車輛搭載全球定位系統(Global Positioning System,簡稱GPS)已經是現今車輛的基本配備了,也因此在取得車輛即時地理位置的座標是沒有問題的,因此便衍伸出了Position-based的路由協定,而Position-based傳統的做法有限制廣播區域、Greedy Forwarding以及劃分區塊等等,但是在VANET中,由於節點移動速度較快加上城市環境格局的限制,上述的做法可能會遇到控制封包損耗過大,或是最短路徑無法順利到達目的地等等問題。 根據VANET中城市環境的格局限制的特性,近年的研究多半是以街道及路口的特性為基礎而衍伸出來的路由協定我們稱為基於路口(Junction-based)的路由協議,加上近年來圖資系統的普及,使得這類的路由協定不需要再進行是否位於路口的判斷。 我們的研究目標為設計一個倚靠路口位置資訊(Junction-based)建立之依照local端紀錄傳輸路徑的VANET路由協定,以提升VANET傳輸路徑的穩定度,在我們的研究中,利用固定的街道與路口資訊結合動態的節點資訊,使封包的傳輸更有效率,由於在都市環境中,車輛行進的叉路,也就是封包傳遞方向的改變,主要發生在路口處,並非在筆直的街道上,因此可以利用我們提出的方法,將節點與所在路口配對,改善以往方法重新搜尋路徑或是找不到適合節點轉傳的問題,因為將節點與路口做了配對,也能改善雖然指定了路口,但是卻沒有節點可以轉傳的問題。 在我們的模擬中,可以看出我們的方法在VANET這樣節點移動頻繁的環境中,不需要增加額外的網路成本,也能準確的搜尋到可以轉傳的節點,進而增進效率。

關鍵字

車載網路 路由 路口

並列摘要


Nowadays vehicles are usually equipped with Global Positioning System (GPS). The protocol that uses GPS in VANET is called Position-based. The Position-based approaches include limited broadcast area, greedy forwarding and dividing the blocks, etc. Because nodes move quickly due to characteristics of the city scenario in VANET, the methods described previously may incur high control packet overhead, with the shortest paths unable to reach the destination successfully. According to the characteristics of the city scenario in VANET, the existing routing protocols divide the city scenarios into streets and junctions. These are called Junction-based routing protocols. With digital maps, the Junction-based protocols in more recent literature do not need to judge the junctions. Designing a Junction-based routing protocol for VANET is our researching target. Using junctions and node information to forward packets, this method can enhance the stability of the transmission paths and can reduce the waste of resources caused by searching paths again and again. In city scenarios, packets change path directions at junctions, not on streets. We use the junction and node information to improve the stability of the transmission paths. The simulation of our research proves our method is suitable for frequent use in mobile V2V environments. The results show that our method can find the node to forward the data accurately and enhance transmission efficiently, without increasing network cost.

並列關鍵字

VANET Routing Junction

參考文獻


[1].F. Li and Y. Wang, “Routing in Vehicular Ad Hoc Networks : A Survey,” IEEE Vehicular Technology Magazine, June 2007, Vol. 2, No. 2, pp. 12 - 22.
[4].M. Mauve, A. Widmer ,and H. Hartenstein, "A Survey on Position-Based Routing in Mobile Ad-Hoc Networks.", IEEE Network Magazine 15 (6) , November 2001, pp. 30-39.
[5].Stojmenovic, "Position-based routing in ad hoc networks.", IEEE. Communications Magazine, 2002, vol. 40, Issue 7, pp. 128-134.
[13].S Tsiachris, G Koltsidas,and FN Pavlidou,” Junction-based geographic routing algorithm for vehicular ad hoc networks.” Wirel. Pers. Commun. 71, 955–973 (2012). doi:10.1007/s11277-012-0854-5
[14].P Sermpezis, G Koltsidas,and F-N Pavlidou,” Investigating a junction-based multipath source routing algorithm for VANETs,” Wireless Commun. IEEE 17, 600–603 (2013)

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