車用網路中低負載的訊息整合傳遞機制

A Low-Overhead message Integration Mechanism in VANETs

陳奕燁(Yi-Yeh Chen)

指導教授 ： 郭文興

元智大學/電機通訊學院/電機工程學系/碩士(2012年)

https://doi.org/10.6838/YZU.2012.00052

摘要

近年來車用網路(VANET)在即時訊息的應用方面相當的盛行。尤其對於緊急訊息的傳遞與路況的分析也越來越多。而在市區道路中，由於有較多的移動車輛，如果缺乏整合機制可能會有過多的訊息及嚴重的碰撞情形產生。因此，本文提出一種低負載的整合傳遞機制，稱為LOIM。將RSU管理範圍內的道路訊息作有效的更新與管理，而藉由合作的傳遞，車輛可以獲得即時的附近道路訊息，同時也可以查詢遠處道路訊息，並且利用冷卻訊息與整合性廣播訊息來減少系統內訊息的傳遞量。
在模擬方面，我們使用NS2模擬此系統的效能，藉由改變地圖上的節點密度與路口密度，來觀察傳遞的成功率、廣播的涵蓋率、訊息查詢的Delay以及RSU上道路訊息的更新狀況。同時，我們也分析比較有無使用整合性傳遞機制的訊息總量。而結果顯示我們的研究不僅可以讓車輛有效獲得即時交通訊息，並且大幅降低系統負載。

關鍵字

車用網路 ； 訊息整合 ； 低負載

並列摘要

In recent years, the applications of real-time messages is very popular in VANET. In particular, the transmission of emergency messages and traffic information has more research. Because of there are many vehicles on the urban roads, it could be too much sending packets and serious collisions if the lack of integration mechanism. Therefore , we propose a Low-overhead Message Integration Mechanism (LOIM) which can managed traffic messages effectively in RSU’s managing range. Vehicle can obtained real-time traffic messages nearby roads and surveyed far traffic messages due to cooperative communication , also reduced sending packets in system using cooldown mechanism and integration broadcasting.
We conduct simulations to evaluate the performance via NS2. We observe successful rate, node receiving rate , delay and traffic message’s updating under different node density and block density. Also , we compared the total messages with and without LOIM. The results showed that our scheme not only provides effective traffic messages to node and significantly reduced system’s overhead.

並列關鍵字

VANET ； message integration ； low-overhead

參考文獻

[3] T. Nadeem, P. Shankar, and L. Iftode, “A comparative study of data dissemination models for VANETs,” in Proceedings of the 3rd Annual International Conference on Mobile and Ubiquitous Systems: Networking & Services, 17-21 July 2006.

[4] Dedicated Short Range Communications Working Group, [Online],Available: http://grouper.ieee.org/groups/scc32/dsrc/.

[5] B. Karp, H.T. Kung, “GPSR: greedy perimeter stateless routing for wireless networks,” Mobile Computing and Networking, 2000, pp. 243–254

[6] Lee K.C., Lee U., Gerla M., “Geo-Opportunistic Routing for Vehicular Networks” Communications Magazine, IEEE ,p.164-170, May ,2010.

[7] G. Korkmaz, E. Ekici, F. O¨ zgu¨ner, “Black-burst-based multihop broadcast protocols for vehicular networks,” IEEE Transactions on Vehicular Technology, vol. 56, no. 5, pp. 3159–3167, 2007.