FCC References Standard on Dedicated Short-Range Communications
Some drivers may breeze through toll booths, with an automatic pass doing all the work, while others are constantly scrambling for change as they approach the toll lane. In either case, its a good bet that not many people have stopped to think much about the technology behind vehicle-to-roadside communications such as those found in toll booths and other types of drive-through payment systems. However, this technology is complex enough that an entire ASTM standard, Specification E 2213, is devoted to some of the future aspects of such communications.
The U.S. Federal Communications Commission is now referencing ASTM Specification E 2213 in its current rules regarding dedicated short-range communication services in the 5.850-5.925 GHz band (5.9 GHz band). E 2213, Specification for Telecommunications and Information Exchange Between Roadside and Vehicle Systems5 GHz Band Dedicated Short Range Communications (DSRC) Medium Access Control (MAC) and Physical Layer (PHY) Specifications, was developed by Committee E17 on Vehicle-Pavement Systems and is under the jurisdiction of E17.51 on Vehicle Roadside Communication.
The purpose of E 2213 is to define the over-the-air radio frequency protocol for a new dedicated short-range communication (DSRC) system. This 75 megahertz range, which was allocated by the FCC in 1998, is used for vehicle-to-vehicle communications, as well as for vehicle-to-roadside communications. These categories cover a wide variety of applications, including vehicle-to-vehicle safety messages, transit vehicle data transfer (gate and yard), traffic information, toll collection, and drive-through payment. The overriding safety issues involved in these applications created the need for a standard way of communicating so that messages would get through quickly and with little interference.
This spectrum is very important, says Richard Doering, Senior Systems Engineer, TransCore. The industry has developed a consensus standard to address the applications with a very robust communications method, following several years of standards meetings.
Specification E 2213 is based on and refers to Institute of Electrical and Electronics Engineers Standards 802.11, Wireless LAN Medium Access Control and Physical Layer Specifications, and 802.11a, Wireless LAN Medium Access Control and Physical Layer Specifications High-Speed Physical Layer in the 5 GHz Band, with permission from IEEE.
According to Doering, the FCCs referencing of E 2213 is a way to guarantee interoperability and minimize interference. Reference of a standard is quite rare by the FCC, Doering says, Many FCC rules for radio communication do not define the communications protocol as is being done for DSRC. .
For further technical information, refer to the DSRC website, www. leearmstrong.com/DSRC/DSRCHomeset. htm, maintained by Lee Armstrong, also an ASTM member, or contact Richard Doering (phone: 858/ 826-4763). Subcommittee E17.51 meets June 8-10 in Detroit, Mich. For membership or meeting details, contact Dan Smith, ASTM International (phone: 610/832-9727). //
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