Multipath query spreading over vehicular ad-hoc networks

Real-time traffic information can effectively be collected from nodes in a vehicular ad hoc network. We consider the problem of spreading a query message from a source node to a destination location over several different paths in the network in order to collect traffic information on road segments in those paths. A query spreading protocol is designed by combining broadcasting and geocasting so that the query message can traverse over a prespecified region between the source node and the destination location. Our simulation result shows that the proposed protocol can cover the segments 80% or more provided that the network has a sufficiently large number of vehicles. However, the variation of the percentage of road segment coverage can highly vary due to an uneven vehicle distribution in the network.