Abstract: During the route maintenance phase, the AODV routing protocol adopts a link repair mechanism. However, this mechanism can’t avoid the rising of packet loss rate and the increasing of transmission delay. To address the issues, this paper proposes an improved method for route maintenance of AODV routing protocol. This method uses the priority nodes judging mechanism in routing discovery phase to prevent the flooding caused by RREQ message, and uses the break link avoiding mechanism in routing maintenance phase to decrease the rate of the packet loss. The two mechanisms are both carried out by calculating link expiration time. The simulation results from the Network Simulator Version 2 (NS2) show that the improved AODV routing protocol performance well in the dense and fast motion VANET.

Key words: AODV, link expiration time, break link avoiding mechanism; priority nodes judging mechanism