Directed information dissemination in vehicular ad-hoc networks

In this article, we utilize the idea of multipoint relays (MPRs) found in literature (Jacquet et al. in Proceedings of IEEE INMIC, 2001), to propagate accident information in a restricted way (e.g., only backwards). We devise an algorithm to identify MPRs that are geographically situated behind a particular node using only its neighbor table, and speed information of the neighboring vehicles. With the identification of the backward MPRs, it is possible to restrict the information dissemination to vehicles behind a particular vehicular ad-hoc network (VANET) node only. This might benefit the approaching vehicles so that the driver could take preventive measures in real-time since he/she will have an indication of the severity of road conditions ahead. We assume that there exists an inter vehicular network using optimized link state routing (OLSR) where accident information can be propagated to all nodes using on-going OLSR control packets. We envision our application will run on top of existing routing protocols (e.g., OLSR), thereby resulting in very little integration effort, and retaining OLSR’s reduced network traffic advantage through the use of MPRs. We analyze our back MPR identification algorithm in a detailed manner. We also show that by using our approach the location of the accident alert instigator node could be pinpointed if a subset of the nodes in the same VANET know their geographical positions. We use VANET mobility models generated by SUMO into NS-3 for our simulations, and also perform preliminary experiments to verify the algorithm's effectiveness. Our analysis and experiments show favorable results

Directed information dissemination in VANET

We assume that there exists an inter vehicular network using OLSR where accident information can be propagated to all nodes using on-going OLSR control packets. In order to ensure relevancy of the information, we want to be able to control the direction to which the information should or should not be sent. In this paper, we discuss our scheme to utilize the network layer information together with the relative speeds of the VANET nodes to identify the entities that are behind a particular vehicle or VANET node without the need of GPS. With this information, we will be able to restrict our information dissemination to vehicles behind a particular VANET node only. We propose an algorithm which identifies the Multi-Point-Relay (MPR) of OLSR that are geographically behind a particular vehicle. We analyze our back MPR identification algorithm in a detailed way. We also show that using our approach the location of the sending node could be pinpointed if a subset of the nodes in the same VANET know their geographical positions. We use VANET mobility models generated by SUMO into NS-3 for our experiments. Our analysis and experiments show favorable results