Improved protocols for spreading vehicle emergency messages in mobile ad hoc networks

This paper proposes relay node selection schemes for propagating vehicle emergency messages (EM) in vehicle mobile ad hoc networks (VMANETs). In the majority of VMANET applications, an EM is propagated in the form of broadcasting. But, typical broadcasting schemes cause some problems, such as high network load, delayed multi-hop propagation, and absence of a range control function, and so on. In this paper we present two competition based relay node selection schemes; one scheme is the Stem and Branch (S&B) protocol that makes use of the sender’s location information, the other scheme is the least common neighbor (LCN) protocol that utilizes the neighbor lists. According to simulation results of highway traffic scenarios, the performance of proposed S&B and LCN protocols is better than that of the previous protocols in all areas and the number of forward messages is largely decreased in these proposed protocols.