Control Overhead Reduction in Cluster-Based VANET Routing Protocol

Vehicular Ad-Hoc NETworks (VANETs) are unique form of Mobile Ad-Hoc NETworks (MANETs), where the nodes act as vehicles moving with relatively high mobility, and moving in a predefined routes. The mobility in VANETs causes high topology changes and in turn leads to excessive control overhead and frequent link communication failures. Traditionally, clustering techniques have been used as the main solution to reduce the control overhead messages in VANET, in which the network is divided into multiple clusters and selecting one of the Cluster Members (CMs) as a Cluster Head (CH). Still, a problem occurs when the control overhead messages increase due to periodically forwarding of CM HELLO (CMHELLO) messages between the CMs and the CH, and when the CH periodically broadcasts an CH advertisement (CHADS) messages to declare itself to the CMs. In this paper, we propose a Control Overhead Reduction Algorithm (CORA) which aims to reduce the control overhead messages in a clustered topology. Therefore, we develop a new mechanism for calculating the optimal period for updating or forwarding the CMHELLO messages between the CMs and the CH. Finally, we evaluate the performance of our proposed work by comparing with other recent researches that published in this field. Based on the simulation results, the CORA algorithm significantly reduces the CMHELLO messages, where it generates the minimum percentage of CMHELLO messages compared with other techniques proposed on this field.