Vehicular communication systems

Vehicular communication systems are computer networks in which vehicles and roadside units are the communicating nodes, providing each other with information, such as safety warnings and traffic information. They can be effective in avoiding accidents and traffic congestion. Both types of nodes are dedicated short-range communications (DSRC) devices. DSRC works in 5.9 GHz band with bandwidth of 75 MHz and approximate range of . Vehicular communications is usually developed as a part of intelligent transportation systems (ITS). The beginnings of vehicular communications go back to the 1970s. Work began on projects such as Electronic Route Guidance System (ERGS) and CACS in the United States and Japan respectively. While the term Inter-Vehicle Communications (IVC) began to circulate in the early 1980s. Various media were used before the standardization activities began, such as lasers, infrared, and radio waves. The PATH project in the United States between 1986 and 1997 was an important breakthrough in vehicular communications projects. Projects related to vehicular communications in Europe were launched with the PROMETHEUS project between 1986 and 1995. Numerous subsequent projects have been implemented all over the world such as the Advanced Safety Vehicle (ASV) program, CHAUFFEUR I and II, FleetNet, CarTALK 2000, etc. In the early 2000s, the term Vehicular Ad Hoc Network (VANET) was introduced as an application of the principles of Mobile Ad-Hoc Networks (MANETs) to the vehicular field. The terms VANET and IVC do not differ and are used interchangeably to refer to communications between vehicles with or without reliance on roadside infrastructure, although some have argued that IVC refers to direct V2V connections only. Many projects have appeared in EU, Japan, USA and other parts of the world for example, ETC, SAFESPOT, PReVENT, COMeSafety, NoW, IVI. Several terms have been used to refer to vehicular communications. These acronyms differ from each other either in historical context, technology used, standard, or country (vehicle telematics, DSRC, WAVE, VANET, IoV, 802.