車載網路上快速與高成功率路由修復演算法之研究

A Fast and High Reconnection Probability Routing Repairing Algorithm for Vehicular Area Networks

鄭宇倫(Yu-Lun Cheng)

指導教授 ： 黃世昌

國立虎尾科技大學/電機資訊學院/光電與材料科技研究所/碩士(2013年)

https://doi.org/10.6827/NFU.2013.00015

摘要

隨著無線通訊技術的快速發展，車載通訊網路近年來也成為無線網路技術中被關注的議題，車輛之間透過分享即時路況資訊至駕駛者，幫助駕駛者迴避擁塞或事故路段，以提升行車安全。這樣的技術亦可提供乘客上網服務、即時資訊的擷取與即時聊天等等，讓行車的旅程更舒適，當然這些服務需要穩定的無線網路通訊連線，確保資料傳遞的成功。而車載通訊網路快速變化的網路拓樸容易導致不穩定的通訊連線，致使多數應用在行動隨意網路(Ad Hoc Network)的路由技術無法適用，所以在高速移動的環境保持穩定的連線已成為車載網路重要的研究議題。目前大多數的研究都是依據連線壽命以及最短路徑來設計，而在高移動性的環境下，若只依車輛之間的連線壽命作為連線重建的依據，忽略節點身旁是否有足夠的車輛，容易產生連線失敗造成更大的通訊成本。因此，本篇論文將著重於設計高速移動的環境下維護車輛之間通訊路徑的方法，藉由改良AODV (ad-hoc on-demand distance vector)的路由機制，建立一條最短路徑以及最長連線壽命網路拓撲。當連線即將斷裂時，所提出的方法會預估連線剩餘可用的時間，提前啟動區域性路由修復，讓發送端與接收端感受不到斷線，達到無接縫連線再建。連線的方式採用雙向啟動，降低單邊連線建立所產生的延遲，同時也控制建立連線時發送的通訊封包數量降低通訊負載。在選取連線重建的位置上，所提出的方法參考鄰近車輛的密度來選擇，降低路由重建時因為節點不足所造成的連線失敗次數。

關鍵字

隨意網路 ； 連線壽命 ； 車輛密度 ； AODV ； 路由修復

並列摘要

The quickly development of wireless communication technology makes the vehicular ad-hoc networks (VANETs) popularly been discussed in the recent year. In the inter-vehicle communication, the vehicles share the real-time traffic information for drivers to avoid road congestions and accidents to increase the safety effectively. For the passengers, VANETs can provide Internet services, real-time information and live-chat. These benefits let passengers feel more convenient in the journey. These services need a stable wireless network communication connection to ensure the success of data delivery. In VANETs, the high-speed mobile environment may cause communication connection becoming unstable. Many technologies used in ad-hoc network are unsuitable for VANETs. How to keep a stable communication connection on the high mobile environment has become an important topic. Current, most of the research focuses on extending the lifetime of path and finding the shortest path. However, in the high mobile environment, considering only the lifetime of path but ignoring the number of nearby vehicles of a node will make connection failed more frequently. The payment introduces greater cost on communication. Therefore, this paper focuses on designing the methods to retain the communication path in the high mobility communication environment. Firstly, we build the shortest path that has a long lifetime. Next, the remaining connection time will be estimated and trigger the local route repair procedure before the communication connection between inter-vehicle fails. The sender and the receiver will not feel the disconnection, and the route can be repaired seamlessly. The bidirectional local route repair is used to reduce the route reconnection time of the unidirectional route rebuilding procedure used in AODV. At the same time, the number of communication packets is also decreased. A method referring to the density of the nearby vehicles for choosing proper nodes to rebuild the route is proposed. The number of times to rebuild the route from source to destination that causes by lacking nodes while performing the route rebuilding can be reduced.

並列關鍵字

VANETs ； Ad-hoc Network ； Route Repair ； AODV ； Vehicle Density

參考文獻

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