{{Short description|Wireless communication standard for vehicles}} '''IEEE 802.11p''' is an approved amendment to the IEEE 802.11 standard to add '''wireless access in vehicular environments''' ('''WAVE'''), a vehicular communication system. It defines enhancements to 802.11 (the basis of products marketed as Wi-Fi) required to support intelligent transportation systems (ITS) applications. This includes data exchange between high-speed vehicles and between the vehicles and the roadside infrastructure, so called vehicle-to-everything (V2X) communication, in the licensed ITS band of 5.9 GHz (5.85–5.925 GHz). IEEE 1609 is a higher layer standard based on the IEEE 802.11p.<ref>{{cite web | url=http://www.standards.its.dot.gov/Factsheets/Factsheet/80 | archive-url=https://web.archive.org/web/20141127220204/http://www.standards.its.dot.gov/Factsheets/Factsheet/80 | url-status=dead | archive-date=November 27, 2014 | title=IEEE 1609 - Family of Standards for Wireless Access in Vehicular Environments (WAVE) | publisher=U.S. Department of Transportation | date=April 13, 2013 | access-date=2014-11-14}}</ref> It is also the basis of a European standard for vehicular communication known as ETSI ITS-G5.<ref>EN 302 663 Intelligent Transport Systems (ITS); Access layer specification for Intelligent Transport Systems operating in the 5 GHz frequency band (https://www.etsi.org/deliver/etsi_en/302600_302699/302663/01.03.01_30/en_302663v010301v.pdf)</ref>
==Description== 802.11p is the basis for dedicated short-range communications (DSRC), a U.S. Department of Transportation project based on the Communications Access for Land Mobiles (CALM) architecture of the International Organization for Standardization for vehicle-based communication networks, particularly for applications such as toll collection, vehicle safety services, and commerce transactions via cars. The ultimate vision was a nationwide network that enables communications between vehicles and roadside access points or other vehicles. This work built on its predecessor ASTM E2213-03 from ASTM International.<ref>{{cite report| url=http://www.astm.org/cgi-bin/SoftCart.exe/DATABASE.CART/REDLINE_PAGES/E2213.htm?L+mystore+erug6226 | title=E2213-03 Standard Specification for Telecommunications and Information Exchange Between Roadside and Vehicle Systems | publisher=ASTM International |doi= 10.1520/E2213-03R10 | access-date= July 15, 2007 | url-access=subscription }}</ref>
In Europe, 802.11p is used as a basis for the ITS-G5 standard, supporting the GeoNetworking protocol for vehicle to vehicle and vehicle to infrastructure communication.<ref>{{cite web | url=http://www.etsi.org/deliver/etsi_es/202600_202699/202663/01.01.00_50/es_202663v010100m.pdf | title=Final draft ETSI ES 202 663 V1.1.0 (2009-11) | publisher= European Telecommunications Standards Institute | access-date=2013-04-16}}</ref> ITS G5 and GeoNetworking is being standardised by the European Telecommunications Standards Institute group for Intelligent Transport Systems.<ref>{{cite web |title= Intelligent Transport Systems |work= Web site |publisher= ETSI |url= http://www.etsi.org/website/technologies/intelligenttransportsystems.aspx |access-date= September 9, 2013 |archive-url= https://archive.today/20130414180015/http://www.etsi.org/website/technologies/intelligenttransportsystems.aspx |archive-date= April 14, 2013 |url-status= dead }}</ref>
=== Context === Because the communication link between the vehicles and the roadside infrastructure might exist for only a short time interval, the IEEE 802.11p amendment defines a method to exchange data through that link without the need to establish a basic service set (BSS), thus without the need to wait on the association and authentication procedures to complete prior to exchanging data. For that purpose, IEEE 802.11p-enabled stations use the wildcard BSSID (a value of all 1s) in the header of the frames they exchange, and may start sending and receiving data frames as soon as they arrive on the communication channel.
Because such stations are neither associated nor authenticated, the authentication and data confidentiality mechanisms provided by the IEEE 802.11 standard (and its amendments) cannot be used. These kinds of functionality must then be provided by higher network layers.
=== Timing advertisement === This amendment adds a new management frame for timing advertisement, which allows IEEE 802.11p enabled stations to synchronize themselves with a common time reference. The only time reference defined in the IEEE 802.11p amendment is UTC.
=== Receiver performance === Some optional enhanced channel rejection requirements (for both adjacent and nonadjacent channels) are specified in this amendment in order to improve the immunity of the communication system to out-of-channel interference. They only apply to OFDM transmissions in the 5 GHz band used by the IEEE 802.11a physical layer.
=== Frequency band ===
IEEE 802.11p standard typically uses channels of 10 MHz bandwidth in the 5.9 GHz band (5.850–5.925 GHz). This is half the bandwidth as used in 802.11a, or double the transmission time per data symbol. This allows the receiver to better cope with the characteristics of the radio channel in vehicular communications environments, especially echoes of signals reflected by moving objects.<ref name="autogenerated344">{{cite book |author1= Sebastian Grafling |author2=Petri Mahonen |author3= Janne Riihijarvi |title= 2010 Second International Conference on Ubiquitous and Future Networks (ICUFN) |chapter= Performance evaluation of IEEE 1609 WAVE and IEEE 802.11p for vehicular communications |date= June 2010 |pages=344–348 |doi= 10.1109/ICUFN.2010.5547184 |isbn= 978-1-4244-8088-3 |s2cid= 18350900 }}</ref>
== History== The 802.11p Task Group was formed in November 2004. Lee Armstrong was chair and Wayne Fisher technical editor. Drafts were developed from 2005 through 2009. By April 2010 draft 11 was approved by 99% affirmative votes and no comments.<ref>{{cite web |title= Status of Project IEEE 802.11 Task Group p: Wireless Access in Vehicular Environments |date= 2004–2010 |publisher=IEEE |url= https://grouper.ieee.org/groups/802/11/Reports/tgp_update.htm |access-date= August 10, 2011 }}</ref> The approved amendment was published July 15, 2010; its title was "Amendment 6: Wireless Access in Vehicular Environments".<ref name="official">{{cite web |title= Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications Amendment 6: Wireless Access in Vehicular Environments |date= July 15, 2010 |work= IEEE 802.11p published standard |publisher=IEEE |url= http://standards.ieee.org/getieee802/download/802.11p-2010.pdf |archive-url= https://web.archive.org/web/20110203012901/http://standards.ieee.org/getieee802/download/802.11p-2010.pdf |url-status= dead |archive-date= February 3, 2011 |access-date= August 10, 2011 }}</ref>
In August 2008, the European Commission allocated part of the 5.9 GHz band for priority transport safety applications<ref>{{CELEX|32008D0671|text=2008/671/EC: Commission Decision of 5 August 2008 on the harmonised use of radio spectrum in the 5875 - 5905 MHz frequency band for safety-related applications of Intelligent Transport Systems (ITS)}}</ref> and inter-vehicle, infrastructure communications.<ref>{{cite web | url=http://europa.eu/rapid/pressReleasesAction.do?reference=IP/08/1240&format=HTML&aged=0&language=EN&guiLanguage=en | title=Cars that talk: Commission earmarks single radio frequency for road safety and traffic management | publisher=European Commission | date=2008-08-05 | access-date=2008-08-23}}</ref> The intention is that compatibility with the USA will be ensured even if the allocation is not exactly the same; frequencies will be sufficiently close to enable the use of the same antenna and radio transmitter/receiver.
Simulations published in 2010 predict delays of at the most tens of milliseconds for high-priority traffic.<ref name="autogenerated344"/>
In November 2020, the FCC reallocated the lower 45 MHz half of the DSRC spectrum (5.850–5.895 GHz) for Wi-Fi and other unlicensed uses,<ref>{{Cite web |date=2020-11-18 |title=FCC Modernizes 5.9 GHz Band to Improve Wi-Fi and Automotive Safety |url=https://www.fcc.gov/document/fcc-modernizes-59-ghz-band-improve-wi-fi-and-automotive-safety |access-date=2022-04-27 |website=Federal Communications Commission |language=en |archive-date=2022-04-27 |archive-url=https://web.archive.org/web/20220427135830/https://www.fcc.gov/document/fcc-modernizes-59-ghz-band-improve-wi-fi-and-automotive-safety |url-status=dead }}</ref> arguing that the auto industry had largely failed to make use of the DSRC spectrum in its 21 years of existence, with only 15,506 vehicles in the US{{spaced ndash}}0.0057% of the total{{spaced ndash}}equipped for DSRC.<ref>{{cite web | url=https://arstechnica.com/tech-policy/2020/11/fcc-adds-45mhz-to-wi-fi-promising-supersize-networks-on-5ghz-band/ | title=FCC takes spectrum from auto industry in plan to "supersize" Wi-Fi | date=18 November 2020 }}</ref>
== Implementations ==
In the Portuguese city of Porto, it is used as a mesh to provide vehicle data between public vehicles and wifi access for its passengers <ref>{{cite web |url=https://www.b2match.eu/m4g-portugal/participants/768 |title=Mission for Growth Portugal – B2B Meetings |publisher=B2match.eu |access-date=2016-05-16 |archive-url=https://archive.today/20150111225520/https://www.b2match.eu/m4g-portugal/participants/768 |archive-date=2015-01-11 |url-status=dead }}</ref>
In Europe, it is foreseen to implement a set of use cases was outlined in the European Commission document "5G Global Developments".<ref>5G Global Developments – SWD (2016) 306, page 9 (http://ec.europa.eu/newsroom/dae/document.cfm?doc_id=17132)</ref>
== See also == *Vehicular Reactive Routing protocol
== References == {{reflist}}
== External links == * {{cite book |doi=10.1109/IEEESTD.2010.5514475 |title=IEEE Std 802.11p-2010 (Amendment to IEEE Std 802.11-2007) |date=15 July 2010 |isbn=978-0-7381-6324-6 }} * [https://web.archive.org/web/20080401144332/http://www.unwired.ee.ucla.edu/dsrc/dsrc_testbed_simple.htm What is DSRC/WAVE?] UCLA article about their testbed (Link not working May 16, 2016) * [http://www.dailywireless.org/2004/07/15/intelligent-transportation-gets-80211p/ Intelligent Transportation gets 802.11p] ''Daily Wireless'' July 15, 2004 * [https://web.archive.org/web/20110514233832/http://www.wi-fiplanet.com/columns/article.php/3422251 When Wi-Fi Will Drive] Adam Stone ''Wi-Fi Planet'' * [https://web.archive.org/web/20181129132433/http://www.vehicularlab.org/ UCLA on campus vehicular testbed] * [https://web.archive.org/web/20180808181432/http://drive-c2x.eu/ Drive C2X] European Integrated Project focussed on rolling out cooperative systems * [http://www.scoref.fr/ SCORE@F] {{Webarchive|url=https://web.archive.org/web/20181228164916/http://www.scoref.fr/ |date=2018-12-28 }} ''(Link not working)'' French FOT on Cooperative System/ Système COopératif Routier Expérimental Français * [http://www.safespot-eu.org/ SAFESPOT] {{Webarchive|url=https://web.archive.org/web/20110301080934/http://www.safespot-eu.org/ |date=2011-03-01 }} European Integrated Project on cooperative vehicular systems for road safety * [http://cvisproject.org/ CVIS] Cooperative Vehicle Infrastructure Systems * [http://www.preserve-project.eu/ PRESERVE] European Project focused on Security and Privacy of V2X communications * [http://etexas.harmonia.com/blog/ DSRC/Wave Vehicle Communication and Traffic Simulator eTEXAS] {{Webarchive|url=https://web.archive.org/web/20190910234424/http://etexas.harmonia.com/blog/ |date=2019-09-10 }}
{{IEEE standards}} {{Autonomous cars and enabling technologies}} {{Authority control}}
{{DEFAULTSORT:Ieee 802.11p}} P