Dedicated short-range communications (DSRC) is a technology for direct wireless exchange of vehicle-to-everything (V2X) and other intelligent transportation systems (ITS) data between vehicles, other road users (pedestrians, cyclists, etc.), and roadside infrastructure (traffic signals, electronic message signs, etc.). [1] DSRC, which can be used for both one- and two-way data exchanges, uses channels in the licensed 5.9 GHz band. DSRC is based on IEEE 802.11p.
In October 1999, the United States Federal Communications Commission (FCC) allocated 75 MHz of spectrum in the 5.9 GHz band for DSRC-based ITS uses. [2] [3] By 2003, DSRC was used in Europe and Japan for electronic toll collection. [4] In August 2008, the European Telecommunications Standards Institute (ETSI) allocated 30 MHz of spectrum in the 5.9 GHz band for ITS. [5]
In November 2020, the FCC reallocated the lower 45 MHz of the 75 MHz spectrum to the neighboring 5.8 GHz ISM band for unlicensed non-ITS uses, citing DSRC's lack of adoption. Of the 30 MHz that remained for licensed ITS uses, 10 MHz was kept for DSRC (Channel 180, 5.895–5.905 GHz) and 20 MHz was reserved for a successor to DSRC, LTE-CV2X (Channel 183, 5.905–5.925 GHz). [6] [7] [3]
Singapore's Electronic Road Pricing scheme plans to use DSRC technology for road use measurement (ERP2) to replace its ERP1 overhead gantry method. [8]
In June 2017, the Utah Department of Transportation and the Utah Transit Authority (UTA) demonstrated the use of DSRC for transit signal priority on SR-68 (Redwood Road) in Salt Lake City, whereby several UTA transit buses equipped with DSRC equipment could request changes to signal timing if they were running behind schedule.
Other applications include:
DSRC systems in Europe, Japan and the U.S. are incompatible and have significant differences, including spectrum and channels (5.8 GHz RF, 5.9 GHz RF, infrared), data transmission rates, and protocols.[ citation needed ]
The European standardization organisation European Committee for Standardization (CEN), sometimes in co-operation with the International Organization for Standardization (ISO) developed some DSRC standards:
Each standard addresses different layers in the OSI model communication stack.
Digital Enhanced Cordless Telecommunications, usually known by the acronym DECT, is a standard used for creating cordless telephone systems and for IoT systems. It originated in Europe, where it is the common standard, replacing earlier cordless phone standards, such as 900 MHz CT1 and CT2.. The IoT usage relies on the new DECT-2020 standard.
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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 300 metres (980 ft). Vehicular communications is usually developed as a part of intelligent transportation systems (ITS).
Vehicular ad hoc networks (VANETs) are created by applying the principles of mobile ad hoc networks (MANETs) – the spontaneous creation of a wireless network of mobile devices – to the domain of vehicles. VANETs were first mentioned and introduced in 2001 under "car-to-car ad-hoc mobile communication and networking" applications, where networks can be formed and information can be relayed among cars. It was shown that vehicle-to-vehicle and vehicle-to-roadside communications architectures will co-exist in VANETs to provide road safety, navigation, and other roadside services. VANETs are a key part of the intelligent transportation systems (ITS) framework. Sometimes, VANETs are referred as Intelligent Transportation Networks. They are understood as having evolved into a broader "Internet of vehicles". which itself is expected to ultimately evolve into an "Internet of autonomous vehicles".
Communications access for land mobiles (CALM) is an initiative by the ISO TC 204/Working Group 16 to define a set of wireless communication protocols and air interfaces for a variety of communication scenarios spanning multiple modes of communications and multiple methods of transmissions in Intelligent Transportation System (ITS). The CALM architecture is based on an IPv6 convergence layer that decouples applications from the communication infrastructure. A standardized set of air interface protocols is provided for the best use of resources available for short, medium and long-range, safety critical communications, using one or more of several media, with multipoint (mesh) transfer.
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IEEE 802.11af, also referred to as White-Fi and Super Wi-Fi, is a wireless computer networking standard in the 802.11 family, that allows wireless local area network (WLAN) operation in TV white space spectrum in the VHF and UHF bands between 54 and 790 MHz. The standard was approved in February 2014. Cognitive radio technology is used to transmit on unused portions of TV channel band allocations, with the standard taking measures to limit interference for primary users, such as analog TV, digital TV, and wireless microphones.
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