Speed-Aware Flow Management with Packet Classification to Mitigate Congestion in VANETs.

Due to service diversity, there may be many packet flows with different urgency and importance in a vehicular ad hoc network (VANET). In a traffic jam, numerous vehicles vie to send packets, which leads to network congestion. Moreover, when accidents occur, the vehicles detecting them will broadcast safety-critical messages to warn others, which could worsen congestion and thus cause the loss of many messages. To this end, the paper proposes a speed-aware flow management with packet classification (SFM-PC) scheme. In SFM-PC, packets will be classified by their services. According to its speed, each vehicle gauges the traffic conditions locally and adjusts the transmission rate of packets by itself. On receiving the packets of safety-critical messages, vehicles use packet consolidation to reduce the dissemination of duplicate messages. Through simulations, we demonstrate that the SFM-PC scheme can efficiently mitigate congestion in a VANET, where it has a much lower packet loss rate than other methods.