Selective message relaying for multi-hopping vehicular networks

Multi-hopping vehicular networks (VANETs) provide environmental awareness across large regions even if there does not exist direct communication between several vehicles within the region. However, the volume of messages that are received and rebroadcasted via the relay vehicles can cause broadcast storms and network jams. In this paper, we propose a selective message relaying algorithm to enable efficient information sharing of multi-hopping VANETs. The proposed algorithm is very general so that it can be applied to many real-world applications. We use a clustering mechanism to group messages that include the same or very similar information, and the number of clusters is adaptively varied based on the proximity of the messages. Supported by the clustering mechanism, each relay vehicle only rebroadcasts a few messages from each cluster. Numerical results show that the proposed algorithm reduces 75% message rebroadcasting but still keeps 98% environmental awareness on average. It can support trade-off analysis between design metrics and assist in future system-level design.