Enhancing Negative Messages Broadcasting with Meet-Table and TTL in VANET.

Abstract A negative message has an objective vehicle and describes the negative attributes of the vehicle. Broadcasting negative messages in VANET is essential to make the VANET secure for these messages are about the untrustworthy vehicles. The Epidemic model can distribute negative messages rapidly with unlimited broadcasting, but uncontrolled Epidemic may cause flooding storm. TTL can be used to control broadcasting, but it may heavily decrease the coverage of negative messages in VANET. Meet-Table is used with TTL to solve the problem. A Meet-Table is a data structure held by a vehicle to record vehicles it met. When a vehicle receives a message, it checks to see if the message’s objective vehicle is in its Meet-Table. If the result is true, the vehicle resets the TTL of the message to the maximum TTL to extend the transmission of the message. Simulation results show that Meet-Table with TTL for the broadcasting of negative messages has high coverage percentage, high accurate coverage percentage, and low delay of time.