802.11j-2004 or 802.11j is an amendment to the
IEEE 802.11
IEEE 802.11 is part of the IEEE 802 set of local area network (LAN) technical standards, and specifies the set of media access control (MAC) and physical layer (PHY) protocols for implementing wireless local area network (WLAN) computer commun ...
standard designed specially for Japanese market. It allows
Wireless LAN
A wireless LAN (WLAN) is a wireless computer network that links two or more devices using wireless communication to form a local area network (LAN) within a limited area such as a home, school, computer laboratory, campus, or office buildi ...
operation in the 4.9 to 5
GHz
The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), equivalent to one event (or cycle) per second. The hertz is an SI derived unit whose expression in terms of SI base units is s−1, meaning that one he ...
band to conform to the Japanese rules for radio operation for indoor, outdoor and mobile applications. The amendment has been incorporated into the published
IEEE 802.11-2007 standard.
802.11
IEEE 802.11 is part of the IEEE 802 set of local area network (LAN) technical standards, and specifies the set of media access control (MAC) and physical layer (PHY) protocols for implementing wireless local area network (WLAN) computer com ...
is a set of
IEEE
The Institute of Electrical and Electronics Engineers (IEEE) is a 501(c)(3) professional association for electronic engineering and electrical engineering (and associated disciplines) with its corporate office in New York City and its operat ...
standards that govern
wireless networking
A wireless network is a computer network that uses wireless data connections between network nodes.
Wireless networking is a method by which homes, telecommunications networks and business installations avoid the costly process of introducing c ...
transmission methods. They are commonly used today in their
802.11a
IEEE 802.11a-1999 or 802.11a was an amendment to the IEEE 802.11 wireless local network specifications that defined requirements for an orthogonal frequency-division multiplexing (OFDM) communication system. It was originally designed to support ...
,
802.11b
IEEE 802.11b-1999 or 802.11b is an amendment to the IEEE 802.11 wireless networking specification that extends throughput up to 11 Mbit/s using the same 2.4 GHz band. A related amendment was incorporated into the IEEE 802.11-2007 standard. ...
,
802.11g and
802.11n
IEEE 802.11n-2009 or 802.11n is a wireless-networking standard that uses multiple antennas to increase data rates. The Wi-Fi Alliance has also retroactively labelled the technology for the standard as Wi-Fi 4. It standardized support for multipl ...
versions to provide wireless connectivity in the home, office and some commercial establishments.
4.9–5 GHz operation in Japan
The 802.11j standard "Wireless LAN Medium Access Control (
MAC) and Physical Layer (
PHY
PHY is an abbreviation for the physical layer of the OSI model and refers to the circuitry required to implement physical layer functions.
PHY or Phy may also refer to:
* Phy, the drug methadone
* Phetchabun Airport (IATA code), Thailand
See ...
) Specifications: 4.9 to 5 GHz Operation in Japan" is designed specially for the Japanese market. Finalized in 2004, the standard works in the 4.9 GHz to 5 GHz band to conform to the Japanese rules for radio operation for indoor, outdoor and mobile applications.
802.11j defines uniform methods that let APs move to new frequencies or change channel width for better performance or capacity—for example, to avoid interference with other wireless applications.
Registration is necessary to use this frequency band. Currently the 4900–5000 MHz spectrum is available for use while 5030–5091 MHz spectrum have been revoked.
In the United States
In the United States, the 4.9 GHz band is reserved for use by public safety wireless applications. The transmission mask is narrower for the public safety band than for consumer part 15 applications. Thus one cannot simply operate 802.11j equipment in the public safety band and be FCC compliant. Public safety agencies are working with manufacturers and the FCC in order to leverage commercial off-the-shelf (COTS) equipment. there were public safety groups working closely with the manufacturing community, federal interests, and standards bodies to create an 802.11 series standard for public safety.
See also
*
IEEE 802.11a
*
IEEE 802.11h
*
IEEE 802.11p IEEE 802.11p is an approved amendment to the IEEE 802.11 standardization, standard to add wireless access in vehicular environments (WAVE), a vehicular communication systems, vehicular communication system. It defines enhancements to 802.11 (the bas ...
References
External links
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