Cluster Merging Weight Factors Study

One of the goals of intelligent communication systems (ITSs) is to improve traffic safety. This can be accomplished by using the communication capabilities made available by vehicular ad-hoc networks (VANETs) to disseminate warning messages to avoid traffic accidents. However, the first proposals were acceptable only up to a certain vehicle density. Above that point, a large number of simultaneous warning message broadcasts, also known as a broadcast storm, rendered the communication medium unusable. Several proposals in the literature came up with ways to limit the number of broadcasts according to some parameter, for instance, a minimum distance from the last broadcaster or a maximum number of hops a message has already traversed on the network, or even clustering vehicles to limit the range of broadcast domains. Notwithstanding, high densities would still form a large number of clusters, which could cause communication problems on cluster boundaries. To alleviate the issue, this work builds on our previously proposed cluster merging scheme combined with several communication chains, focusing on different combinations of weight factors that change the importance of a vehicle number of neighbors, speed difference to the cluster average, and received power from the closest base station when electing a cluster master for a merged cluster. The presented results show that such factors have great impact on the number of informed vehicles on the VANET and on the delay to warn the last vehicle.