802.11


Also found in: Dictionary, Thesaurus, Medical, Legal, Acronyms, Wikipedia.

802.11

Commonly known as "Wi-Fi," the IEEE 802.11 standards provide the wireless counterpart to Ethernet, and the Wi-Fi Alliance certifies products. All versions use OFDM encoding except for the earlier 802.11b, which uses DSSS (see OFDM and spread spectrum). For details about each standard, see table below and 802.11 versions.

Infrastructure and Ad Hoc Modes
In "infrastructure" mode, Wi-Fi devices transmit to an "access point" (base station), which may be a stand-alone unit or built into a wireless router. In "ad hoc" mode, two wireless devices communicate peer-to-peer without an access point in between. Another direct connection mode is also available (see Wi-Fi Direct).

Throughput Varies
Speed is distance dependent. The farther away the device from the base station, the lower the speed. Also, the actual throughput is generally half of the rated speed because 802.11 uses collision "avoidance" (see CSMA/CA) rather than Ethernet's collision "detection" method (see CSMA/CD). For example, a rated 54 Mbps may yield 27 Mbps in real data throughput. For more about Wi-Fi networks, see wireless LAN and Wi-Fi. See Wi-Fi hotspot, 802.11 timeline, wireless router, ISM band, 802.16 and 802.15.

    802.11 SPECIFICATIONS              Max    Indoor  Channel    Bands   Speed   Range*   Width    (GHz)   (Mbps)  (ft)     (MHz)11ac      5  433***  230   20/40/80/160
 11n  2.4, 5  150**   230   20/40
 11a       5   54      95   20
 11g  2.4      54     170   20
 11b  2.4      11     150   20

   * = Up to 4x farther outdoors.
  ** = Per antenna at 40 MHz channels.
 *** = Per antenna at 80 MHz channels.


Wi-Fi Access Points
Wi-Fi devices transmit to central base stations called "access points" (APs), such as these ceiling-mounted and desktop examples (bottom). The circuitry in an access point is also built into a wireless router.


Wi-Fi Access Points
Wi-Fi devices transmit to central base stations called "access points" (APs), such as these ceiling-mounted and desktop examples (bottom). The circuitry in an access point is also built into a wireless router.







Wi-Fi Adapters
The adapter (top) adds Wi-Fi to any computer via USB, while the card on the bottom plugs into a PCI slot inside a desktop computer. (Images courtesy of D-Link Corporation and TP-LINK Technologies Co., Ltd.)
References in periodicals archive ?
PacketGenie(TM) along with the accompanying software stack provides a flexible multi-protocol MAC and baseband implementation, which can be configured to work with all planned variants of the 802.
The Fiercest 15 companies all combine breakthrough technology with smart strategy and solid management," said Ben Frankel, Editor of The 802.
Quatech is pleased to deliver a line of highly reliable 802.
AIRONET will continue to work closely with companies such as NCR Corporation and Proxim to develop truly interoperable standards through the group efforts of the IEEE 802.
the leader in third-generation wireless mesh products for high performance data, video, and voice applications, also announced new features in its MD4000 family of Structured Mesh(TM) wireless nodes to bolster security and fine-tune performance in demanding outdoor 802.
As a leading supplier in machine-to-machine connectivity, Quatech is pleased our 802.
Wireless ePULSE solutions have been reporting data over Michigan roadways for the past year and have helped validate Michigan Department of Transportation 802.
OTCBB: DPAC) and a leader in high performance device networking solutions, announced the launch of the next generation of its entire family of Airborne(TM) 802.