The increasing percentage of people depending upon vehicular transportation has steered issues related to safety and traffic jams.VANET is a variant of MANET in which nodes are replaced by vehicles. VANET is a primary component of intelligent transportation systems (ITS) that is envisioned towards providing road safety and comfort zones to their users. Apart from safety VANET also provides several value-added services like audio/video sharing and other multimedia applications etc.
VANETs are self-organized communication networks with minimal deployment cost. Each vehicle in VANETs is equipped with wireless devices to communicate with each other and exchange some data between vehicles and Road Side Units (RSUs) without any infrastructure. VANET systems offered a number of applications including a lot of benefits for administration, driving, and convenience in vehicles.
VANET architecture divides into three types of networks:
1. Vehicle-to-Vehicle (V2V) ad-hoc network: it is a network in which nodes communicate with each other directly without a fixed infrastructure.
2. Vehicle-to-Infrastructure (V2I) network: it is a network in which nodes communicate with the roadside unit.
3. Hybrid network: it combines both V2V and V2I networks.
The important task of VANET is providing data communication in vehicular areas using a wireless transmission to avoid accidents by sending data of vehicle’s speed and position to another over a network. To achieve this goal, needs to design routing protocols considering factors such as the security, mobility, and scalability of vehicular communication. There are many routing protocols in an ad hoc environment, but in VANET, routing is a difficult task to achieve because of its high mobility, low latency, and high growth in size, network, privacy, and security requirements.
Routing messages from one vehicle to another is one of the most significant problems in VANETs. Traditional routing and transmitting protocols are designed for completely connected networks or MANETs. Therefore, those protocols cannot be used effectively and efficiently in vehicular ad hoc networks (VANETs). The routing protocols for VANETs are expected to support vehicular traffic on a large scale, high mobility behavior of vehicles, and frequent link breakage. Routing protocol in such an environment defines some path to establish peer-to-peer connectivity among network nodes.
The main objective of any routing approach is to define the best path from the source to destination node with minimal overhead. There are several routing approaches that have been designed for vehicular network environments. These approaches have been analyzed properly by their advantages and shortcomings. Therefore, all approaches can be classified based on different parameters such as, based on routing characteristics, routing strategies, routing information, quality of services and network structure etc. Several classifications of routing protocols have been suggested based on different perspectives.
VANET routing protocols are extensively categorized into Topology based, Position based, Cluster based, Broadcast and Geocast based protocols. Article presents a detailed discussion of the routing protocols for VANETs and their characteristics.
1. Topology-Based Routing Protocols
2. Position based routing protocol.
3. Broadcast routing protocol
4. Cluster Routing protocols
5. Geo-Cast routing protocols
Dr. Mukesh Dixit
SAGE School of Engineering and Technology