Shiwani
Computer Science and Engineering Dept.
DCRUSTM
Murthal, Sonipat, India
shiwanijaglan@gmail.com
Dinesh Singh
Computer science and Engineering Dept.
DCRUSTM
Murthal, Sonipat, India
Dinesh.madhav@gmail.com
ABSTRACT
Vehicular ad hoc networks (VANETs) are an application of mobile ad hoc network (MANET) that improve road safety and provide travelers comfort. However they differ from MANET by their architecture, threats, attributes and applications. In this paper we present information related to the field, distinguish the main features surrounding VANET, and a review of different routing protocols used.
INTRODUCTION
VANETs stand for the Vehicular Ad-hoc Networks. A VANET is a type of Mobile Ad-hoc Network (MANET). A MANET is a self forming
network and very flexible, which has some characteristics like dynamic topologies, less bandwidth and energy consumption and it can function without the need of any centralized control. So VANET is wireless communication between vehicle to vehicle and vehicle to roadside infrastructure based on wireless local area network (WLAN) technology. Each node in an ad hoc network acts as both a data terminal and a router [2]. The nodes in the network then use the wireless medium to communicate with other nodes in their radio range. The advantage of using ad hoc networks is it is possible to deploy these networks in areas where it isn't feasible to install the needed infrastructure. Another advantage of ad hoc networks is they can be quickly deployed with no administrator involvement. The legislation of a large scale vehicular network would be a difficult task. These reasons contribute to the ad hoc networks being applied to vehicular environments.
Components of VANETs
There are three components of VANET:
(i) On-Board Unit (OBU)
The OBU is equipped on a vehicle for inter-vehicles communications or communications between the vehicle and roadside units. An antenna is equipped in an OBU such that the vehicle communications with each other or the roadside units can be made.
(ii) Road Side Unit (RSU)
The RSU are allocated along the roads. The main function of the roadside units is to bypass the messages between the vehicles and trust authority.
(iii) Trust Authority (TA)
The Trust Authority is a server which is managed by a service provider or the government. The function of a trust authority is to maintain the service, to keep the records of each vehicle or to issue the certificate for each vehicle.
Figure 1 Vehicular Ad Hoc Network (ref. to 22)
VANET Communication Domains
In- Vehicle Domain
This domain consists of an OBU and one or multiple AUs.
The OBU provides a communication link to the AU in order to execute one or more of a set of applications provided by the application provider using the communication capabilities of the OBU.
ADHOC Domain
The ad hoc domain on VANET consists of vehicles equipped with OBUs and a station along the road side, the RSU.
Two types of communications are there in the ad hoc domain:
1. Vehicle to vehicle communication (V2V)
2. Vehicle to infrastructure communication (V2I)
Infrastructural Domain
The RSU can connect to the infrastructural networks or to the Internet, allowing the OBU to access the infrastructure network.
AUs are registered with the OBU to connect to any internet based host. OBU can also communicate with other hosts
for non-safety applications, using the communication of cellular radio networks (GSM, GPRS, UMTS, HSDPA, WiMax and 4G)
Fig 2(ref. to 23)