Software-Defined Vehicular Adhoc Network: A Theoretical Approach

1. Introduction

In recent years, traffic safety has been major concern. Not even traffic safety, the manufactures are concerning to provide many applications which could make travelling effortlessly and conveniently. In order to achieve these, road safety and other application, it is necessary to have a network which is capable of providing all the data efficiently to the vehicles. A network with the capability of mobile ad-hoc network in vehicles can give the solution of required network such type of network is Vehicular Ad-hoc Network. The nodes in VANET is equipped with the Wireless communication system. The nodes in VANET are fast moving hence, unlike the conventional network, each node has the capability of routing and end system working. To achieve the proper communication among vehicles, all vehicles are equipped with OBU (On Board Unit) by which vehicles can directly communicate with the vehicles. There is another infrastructure, RSU (Road Side Unit), installed along road side to communicate vehicles.

To standardise these communications, IEEE communication society has approved a standard 802.11p for DSRC (Dedicated Short-Range Communication) / WAVE (Wireless Access in Vehicular Environment) Protocol. The 802.11p facilitates the communication between high speed vehicles and between road side infrastructure and vehicles i.e. V2X.

The IEEE defines the architecture and standardizes the services and interface in 1609 family for WAVE Protocol stack, for high speed, short range and low latency wireless communication in the vehicular environment. The WAVE protocol stack along with the standards is given in figure.

Figure 1.

DSRC/WAVE Protocol Stack

1.1 Network Architectures of VANET

The architecture of VANET falls within three categories first a pure wireless ad hoc network where vehicle to vehicle without any support of infrastructure. Second a wired backbone network with wireless hops that give an impression of wireless vehicular network and third is hybrid structure, the communication between the roadside units (RSU), a fixed infrastructure.

1.1.1 Pure Cellular/WLAN

Like the cellular network, Cellular gateways or access point is installed on roadside or traffic intersection. When a vehicle enters into the access point range, it connects to the access point. Vehicle node can communicate through these access point only as the nodes don’t have any gateway capabilities.

1.1.2 Pure Ad Hoc

This architecture does not follow the concept of the cellular network. All vehicles along with roadside wireless unit form a mobile ad-hoc network. All moving nodes have the gateway capability. Any moving vehicle can communicate with other moving vehicle using the ad-hoc network.

1.1.3 Hybrid

This network architecture uses the benefit of cellular and ad-hoc network architecture. All moving vehicles have the capability of gateway and network routers by which they are capable of communicating each vehicle inside the ad-hoc network. The roadside unit gives the facility of the cellular network. The roadside unit is connected to the outside world using the internet. Hence, the moving vehicle can be connected to the outside world through a roadside unit.

Figure 2.

The C2C -CC reference communications