Editing IEEE 802.11 (section)

===802.11af===
{{Main|IEEE 802.11af}}

IEEE 802.11af, also referred to as "White-Fi" and "[[Super Wi-Fi]]",<ref name="80211afLekomtcev">{{cite magazine|title=Comparison of 802.11af and 802.22 standards – physical layer and cognitive functionality|url=http://www.elektrorevue.cz/file.php?id=200000861-9a19f9b13f|date=June 2012|access-date=2013-12-29|last1=Lekomtcev|first1=Demain|last2=Maršálek|first2=Roman|magazine=Elektrorevue|volume=3|issue=2|issn=1213-1539}}</ref> is an amendment, approved in February 2014, that allows WLAN operation in TV [[White spaces (radio)|white space spectrum]] in the [[VHF]] and [[UHF]] bands between 54 and 790&nbsp;MHz.<ref name="80211timeline"/><ref name="80211afflores">{{cite web|title=IEEE 802.11af: A Standard for TV White Space Spectrum Sharing|url=http://networks.rice.edu/papers/FINAL_article_80211af.pdf|publisher=IEEE|last1=Flores|first1=Adriana B.|last2=Guerra|first2=Ryan E.|last3=Knightly|first3=Edward W.|last4=Ecclesine|first4=Peter|last5=Pandey|first5=Santosh|date=October 2013|access-date=2013-12-29|url-status=dead|archive-url=https://web.archive.org/web/20131230232954/http://networks.rice.edu/papers/FINAL_article_80211af.pdf|archive-date=2013-12-30}}</ref> It uses [[cognitive radio]] technology to transmit on unused TV channels, with the standard taking measures to limit interference for primary users, such as analog TV, digital TV, and wireless microphones.<ref name="80211afflores"/> Access points and stations determine their position using a satellite positioning system such as [[GPS]], and use the Internet to query a [[TV White Space Database|geolocation database (GDB)]] provided by a regional regulatory agency to discover what frequency channels are available for use at a given time and position.<ref name="80211afflores"/> The physical layer uses OFDM and is based on 802.11ac.<ref name="80211afLim">{{cite web|url=http://edu.tta.or.kr/sub3/down.php?No=139&file=1-4_TVWS_Regulation_and_Standardization_%C0%D3%B5%BF%B1%B9.pdf|first=Dongguk|last=Lim|title=TVWS Regulation and Standardization (IEEE 802.11af)|date=2013-05-23|access-date=2013-12-29|archive-url=https://web.archive.org/web/20131231001459/http://edu.tta.or.kr/sub3/down.php?No=139&file=1-4_TVWS_Regulation_and_Standardization_%C0%D3%B5%BF%B1%B9.pdf|archive-date=2013-12-31|url-status=dead}}</ref> The propagation path loss as well as the attenuation by materials such as brick and concrete is lower in the UHF and VHF bands than in the 2.4&nbsp;GHz and 5&nbsp;GHz bands, which increases the possible range.<ref name="80211afflores"/> The frequency channels are 6 to 8&nbsp;MHz wide, depending on the regulatory domain.<ref name="80211afflores"/> Up to four channels may be bonded in either one or two contiguous blocks.<ref name="80211afflores"/> MIMO operation is possible with up to four streams used for either [[space–time block code]] (STBC) or multi-user (MU) operation.<ref name="80211afflores"/> The achievable data rate per spatial stream is 26.7&nbsp;Mbit/s for 6 and 7&nbsp;MHz channels, and 35.6&nbsp;Mbit/s for 8&nbsp;MHz channels.<ref name="80211afDraft"/> With four spatial streams and four bonded channels, the maximum data rate is 426.7&nbsp;Mbit/s for 6 and 7&nbsp;MHz channels and 568.9&nbsp;Mbit/s for 8&nbsp;MHz channels.<ref name="80211afDraft"/>