Vehicular Ad Hoc Networks (VANETs): Enabling Intelligent Transportation Systems

A vehicular ad-hoc network (VANET) is a subclass of Mobile Ad-Hoc Network (MANET). This technology is important for vehicles and their interaction with the surrounding environment. It has aided in congestion avoidance, intersection control, accident avoidance, and emergency management in the transport sector.

Due to its high level of mobility, increased network traffic, and real-time application, it has made it key in the innovation and actualizing of Intelligent Transport Systems (ITS); that enable communication between nearby vehicles and roadside infrastructure thus aiding in improving automotive vehicles and highway security, traffic reliability, and vehicle and passenger safety are all priorities.

It acts as a self-organizing network, allowing vehicles to act as wireless routers and create a network within a range of approximately 100 to 300 meters in urban areas and up to 1000 meters on highways.

Vehicles are built with wireless units to communicate with neighboring ones directly through single or multi-hops in a vehicle-to-vehicle (V2V) style or Vehicle-to-pedestrian (V2P), or Road Side Units (RSUs) in a Vehicle-to-Infrastructure (V2I) or Infrastructure-to-Vehicle (I2V) style.

The VANET supports traffic management to facilitate navigation, safety, and services to end-users. It uses TDMA (Time Division Multiple access) MAC (Medium Access Control) technology, a protocol used in wireless communication networks to manage how multiple devices share the same communication medium.

There are embedded sensors in vehicles and on roadsides to predict changes that are limited to road and traffic rules. Data is collected about the environment, velocity, density, and direction, which is used to assist in street traffic safety hence proving the workability of the Intelligent Transport System.

VANET is characterized by geographic topology, predictable mobility, vehicle density, and varying channel capacity. This technology consists of groups of moving or stationary vehicles connected by a wireless network, sharing information about road conditions and other vehicles to ensure smooth maneuvering while traveling mostly in the big cities.

Routing packets and information to their destination has been a challenge due to the extreme mobility and dynamism of the nodes. In an approach to solve the issue of data dissemination, the cluster approach is used for improvement, where a virtual collection of vehicles having related characteristics, separates various vehicles into groups according to certain rules to solve the problem of hierarchical network topology. 

Intelligent Transport System is enabled by provision of:

• Vehicle’s location

• Current velocity

• Direction of travel

• Driver’s behavior, i.e., Indicator, and brake lights.

• Traffic conditions, whether there is congestion, an accident, road construction, or road closure.

VANET is formed of vehicles, i.e., cars, buses, tracks, and road signs that are equipped with positioning systems like GPS devices, wireless communication devices (such as IEEE 802.11p/WAVE network interfaces), and digital maps.

DSRC (Dedicated Short-Range Communication) is considered the most appropriate standard for wireless communication in vehicular ad-hoc networks.

Because:

• It provides high data transfer; bandwidth up to 6-27 Mbps

• Low communication latency

• Transmit communication at a reasonable range of 300-1000 meters

• Low power consumption

• Supports vehicle speeds exceeding 200 km/h

The VANET technology has several limitations concerning as far as Intelligent Trasnportation System is concerned:

✓ Medium access control (MAC) in ensuring efficient and fair access to the communication medium.

✓ Physical communication in real-time in dynamic environments.

✓ Routing protocol for changing topologies due to high mobility.

✓ Congestion control to manage data traffic and prevent network congestion.

✓ Fault tolerance to ensure network reliability despite failures.

✓ Multi-modal interactions of different modes of transport and the stationary structure and devices that facilitate the network should be put into consideration for compatibility.

✓ End-to-end data transport that ensures reliable data delivery from source to destination due to the high speeds of some of the vehicles.

✓ Security and privacy in the protection of collected data and the access of automated vehicles without authorization since communication is over the internet.

✓ Simulation and implementation platforms that ensure accurate simulation tools and practical implementation platforms need a lot of serious training before implementing.

✓ Safety and non-safety information management for handling both sensitive and non-sensitive information is questionable.

✓ Quality of Service Assurance (QoA) that ensures high-quality communication services is not assured.

✓ Infotainment Applications that support entertainment and information services for passengers.