In this paper we address one research challenges in vehicular ad hoc networks (VANETs), Safety message dissemination as follows. We investigate the quality of service for beacon based safety applications in VANETs. We point out the fact that safety applications have some distinctiveness which is not addressed in the current literature. We therefore propose a new metric focusing on the significance of coverage in safety scenarios called effective range which is based on the satisfaction of very restrict quality of service. We also emphasis that beacon based safety applications may tolerate some message loss Beacon safety message dissemination in Vehicular Ad-hoc Networks (VANETs) suffers from poor reliability especially in congested road traffics. The main origin of this problem is CSMA nature of Dedicated Short Range Communications (DSRC) in MAC layer. In this paper, a scheduling algorithm in the application layer is proposed to alleviate the problem. We first divide the road into a number of geographical sections. In each section, we form a cluster between moving vehicles. Then we perform a scheduling algorithm including two levels. In the first level, nonadjacent clusters can transmit at the same time. While the second level of scheduling deals with inside of each cluster in which we implement a TDMA-like approach. Simulation results show that the proposed algorithm improves the reliability in beacon message dissemination. Moreover, the accuracy of the information which each vehicle can obtain from its neighboring vehicles is significantly increased. Thus the proposed scheduling scheme leads to considerable enhancement of the safety level provided by Beacon Safety Messages (BSMs).
Comments: 9 Pages.
[v1] 2012-08-18 21:42:29
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