Store-Carry-Forward Message Dissemination in Vehicular Ad-Hoc Networks with Local Density Estimation

In vehicular ad hoc networks, node density is highly variable in time and space. Communication success depends on the density of nodes, as a higher density increases the reliability of wireless links. Thus knowing the density of a vehicular communication system is important as better opportunities for wireless communication can be realized. In this paper, Velocity Aware Density Estimation (VADE) is introduced. In VADE, a car estimates the density of neighboring vehicles by tracking its own velocity and acceleration pattern. VADE is accurate because it employs sufficient information for density estimation. An opportunistic forwarding procedure, based on VADE estimation, is also proposed. In this procedure, data forwarding is done when the probability of having a neighbor is high, which dramatically reduces the probability of packets being dropped. Simulation results are presented which confirm the validity of our approach.