Optimal Adaptive Data Dissemination Protocol for VANET Road Safety Using Optimal Congestion Control Algorithm
Authors: Raj Bhavani Sundar , Chandrasekaran Srimathi 
Published: April 2019

Introduction:
VANET is a mobile ad-hoc system (MANET) that concerns vehicle-to-vehicle and
vehicle-to-infrastructure communication. Unique characteristics such as higher node speeds and restricted
road topology extricate VANET from other MANETs. Messages between vehicles and roadside infrastructure
in VANET is over short to medium range wireless technologies. Dedicated Short Range Communications
(DSRC) is a RF technology-based standard that has been designed exclusively for automotive communications.
Like most MANETs, data are broadcasted in VANETs through the exchange of messages between
the nodes. The limited road topology unlike MANETs, executes a directional way to the message flow. It
becomes important that the data to be transmitted in the most effective ways with less delay, due to higher
node speeds and unbalanced connectivity among the nodes. Hence, propagating data to the intended node or
region of interest is a unique problem in VANETs and requires incorporating effective techniques to disseminate
data. Data broadcasted from a vehicle will be received by all the nodes within the broadcast range. The
difficulty of data dissemination is hence related to propagating data, not within but beyond the transmission
range of the sender. An intuitively simple way to disseminate data beyond the transmission range is through
flooding. In flooding each node which receives the message would simply rebroadcast the message without
any regard to its current position or any other factors. Thus, data are propagated beyond the transmission
range when a node at the border of the broadcast range rebroadcasts the message. For effective broadcasting,
each vehicle upon receiving a message would make a decision to rebroadcast the message depending on
whether or not it is the farthest node in the transmission range. Thus, the decision-making ability of each vehicle
on participating in the message propagation is dependent on its awareness of vehicles around it and
determines the overall effectiveness of the technique used in disseminating data.

Objective:
To identify an optimal cluster head based on effective parameters to reduce Control Overhead
messages in a collision based traffic network.

Methods:
The proposed system consists of two processes namely candidate selection and control OH message
reduction. The candidate selection process is carried out by Chaotic Fish Swarm Optimization (CFSO)
algorithm which consists of cluster formation and Cluster Head (CH) selection. The control OH messages
are reduced by a Predictor based Decision Making (PDM) algorithm.

Results:
Based on the performance metrics such as success rate, redundant rate, collision rate, number of control
OH messages, data propagation distance, data propagation time and data dissemination efficiency, the proposed
system is evaluated. The results shows that the proposed system performs well than the existing system.

Conclusion:
In this paper, we have suggested an Optimal Adaptive Data Dissemination Protocol (OAddP)
for VANET road safety. The proposed OAddP mechanism uses the Chaotic Fish Swarm Optimization
(CFSO) algorithm to perform the clustering and uses a Predictor based Decision Making (PDM) algorithm
for control overhead messages reduction.