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IEEE 802.11n is a proposed amendment to the IEEE 802.11-2007 standard to improve system performance.

802.11 is an IEEE standard that allows devices such as laptop computers or cellular phones to join a Wireless LAN widely used in the home, office and some commercial establishments. Although the N standard is still in "draft" stage according to the IEEE, many hardware vendors already sell "pre-N" or "Draft-N" hardware, based on the most recent draft. These vendors anticipate the final version will not be significantly different from the draft, and in a bid to get the early mover advantage, are pushing ahead with the technology.

The 802.11n standard is expected to be significantly faster than previous standards, such as 802.11b and 802.11g, with many experts proclaiming that this wireless technology will finally allow consumers to move beyond traditional wired LAN [1].

Description

802.11n builds on previous 802.11 standards by adding multiple-input multiple-output (MIMO). MIMO uses multiple transmitter and receiver antennas to improve the system performance. The transmitter and receiver use precoding and postcoding techniques, respectively, to achieve the capacity of a MIMO link. Precoding includes spatial beamforming and spatial coding, where spatial beamforming improves the received signal quality at the decoding stage. Spatial coding can increase data throughput via spatial multiplexing and increase range by exploiting the spatial diversity, through techniques such as Alamouti coding. The number of antennas relates to the number of simultaneous streams: two receivers and two transmitters (2x2) or four receivers and four transmitters (4x4). The standards requirement is a 2x2 with a maximum two streams, but allows 4x4.

The Enhanced Wireless Consortium (EWC)[2] was formed to help accelerate the IEEE 802.11n development process and promote a technology specification for interoperability of next-generation wireless local area networking (WLAN) products[3].

An 802.11 access point may operate in one of three modes:
  1. Legacy (only 802.11a, and b/g)
  2. Mixed (802.11a, b/g, and n)
  3. Greenfield (only 802.11n) - maximum performance

Status

Work on the 802.11n standard dates back to 2004. Publication is currently expected in September 2008,[4] but major manufacturers are now releasing 'pre-N', 'draft n' or 'MIMO-based' products based on early specs.

Timeline

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  • January 2004 - IEEE announced that it had formed a new 802.11 Task Group (TGn) to develop a new amendment to the 802.11 standard for wireless local-area networks. The real data throughput will reach a theoretical 270 Mbit/s for the required dual stream MIMO device. (which may require an even higher raw data rate at the physical layer), and should be up to 20 times faster than 802.11b, and up to 3 times faster than 802.11a and up to 4 times faster than 802.11g.
  • July 2005 - Previous competitors TGn Sync, WWiSE, and a third group, MITMOT, said that they would merge their respective proposals as a draft. The standardization process is expected to be completed by the second quarter of 2009.
  • 19 January 2006 - the IEEE 802.11n Task Group approved the Joint Proposal's specification, based on EWC's draft specification.
  • March 2006 - the IEEE 802.11 Working Group sent the 802.11n Draft to its first letter ballot, allowing the 500+ 802.11 voters to review the document and suggest bugfixes, changes and improvements.
  • 2 May 2006 - the IEEE 802.11 Working Group voted not to forward Draft 1.0 of the proposed 802.11n standard. Only 46.6% voted to approve the ballot. To proceed to the next step in the IEEE standards process, a majority vote of 75% is required. This letter ballot also generated approximately 12000 comments -- much more than anticipated.
  • November 2006 - TGn voted to accept draft version 1.06, incorporating all accepted technical and editorial comment resolutions prior to this meeting. An additional 800 comment resolutions were approved during the November session which will be incorporated into the next revision of the draft. As of this meeting, three of the 18 comment topic ad hoc groups chartered in May have had completed their work and 88% of the technical comments had been resolved with approximately 370 remaining.
  • 19 January 2007 - the IEEE 802.11 Working Group unanimously (100 yes, 0 no, 5 abstaining) approved a request by the 802.11n Task Group to issue a new Draft 2.0 of the proposed standard. Draft 2.0 was based on the Task Group's working draft version 1.10. Draft 2.0 was at this point in time the cumulative result of thousands of changes to the 11n document as based on all previous comments.
  • 7 February 2007 - the results of Letter Ballot 95, a 15-day Procedural vote passed with 97.99% approval and 2.01% disapproval. On the same day, 802.11 Working Group announced the opening of Letter Ballot 97. It invited detailed technical comments to closed on 9 March 2007.
  • 9 March 2007 - Letter Ballot 97, the 30-day Technical vote to approve Draft 2.0, closed. They were announced by IEEE 802 leadership during the Orlando Plenary on 12 March 2007. The ballot passed with an 83.4% approval, above the 75% minimum approval threshold. There were still approximately 3,076 unique comments, which will be individually examined for incorporation into the next revision of Draft 2.
  • 22 August 2007 - Almost 70 products certified for compliance with Draft 2.0 of the 802.11n.
See also: 802.11 non-standard equipment#Pre-802.11n equipment

External links

References

1. ^ [1] 802.11n to overtake wired Ethernet
2. ^ [2] Enhanced Wireless Consortium
3. ^ 802.11n to overtake wired Ethernet (2007-10-08). Retrieved on 2007-10-08.
4. ^ Official IEEE 802.11 working group project timelines (2007-07-02). Retrieved on 2007-07-09.
IEEE 802.11 is a set of standards for wireless local area network (WLAN) computer communication, developed by the IEEE LAN/MAN Standards Committee (IEEE 802) in the 5 GHz and 2.4 GHz public spectrum bands.

Although the terms 802.
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IEEE 802.11 is a set of standards for wireless local area network (WLAN) computer communication, developed by the IEEE LAN/MAN Standards Committee (IEEE 802) in the 5 GHz and 2.4 GHz public spectrum bands.

Although the terms 802.
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Institute of Electrical and Electronics Engineers

Type Professional Organization
Founded January 1, 1963
Origins Merger of the American Institute of Electrical Engineers and the Institute of Radio Engineers
Key people Leah H.
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standardization or standardisation can have several meanings depending on its context. Common use of the word standard implies that it is a universally agreed-upon set of guidelines for interoperability.
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wireless LAN or WLAN is a wireless local area network, which is the linking of two or more computers without using wires. WLAN utilizes spread-spectrum or OFDM modulation technology based on radio waves to enable communication between devices in a limited area, also known as
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IEEE 802.11b-1999 or 802.11b, is an amendment to the IEEE 802.11 specification that extended throughput to up to 11 Mbit/s using the same 2.4 Ghz band. This specification under the marketing name of Wi-Fi has been implemented all over the world.
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This aricle needs sources or references that appear in reliable, third-party publications. Alone, primary sources and sources affiliated with the subject of this article are not sufficient for an accurate encyclopedia article.
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local area network (LAN) is a computer network covering a small geographic area, like a home, office, or group of buildings. The defining characteristics of LANs, in contrast to Wide Area Networks (WANs), include their much higher data transfer rates, smaller geographic range, and
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Multiple-input and multiple-output, or MIMO, (pronounced mee-moh or mai-moh) refers to the use of multiple antennas both at the transmitter and receiver to improve the performance of radio communication systems.
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transmitter (sometimes abbreviated XMTR) is an electronic device which with the aid of an antenna propagates an electromagnetic signal such as radio, television, or other telecommunications.
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A radio receiver is an electronic circuit that receives its input from an antenna, uses electronic filters to separate a wanted radio signal from all other signals picked up by this antenna, amplifies it to a level suitable for further processing, and finally converts through
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antenna is a transducer designed to transmit or receive radio waves which are a class of electromagnetic waves. In other words, antennas convert radio frequency electrical currents into electromagnetic waves and vice versa.
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6 (3): 311–335.
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Beamforming is a signal processing technique used with arrays of transmitting or receiving transducers that control the directionality of, or sensitivity to, a radiation pattern.
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Spatial multiplexing is a transmission technique in MIMO wireless communication to transmit independent and separately encoded data signals, so called streams, from each of the multiple transmit antennas.
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greenfield is a project which lacks any constraints imposed by prior work. The image is that of construction on greenfield land, where there is no need to remodel or demolish an existing structure.
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Prose is writing distinguished from poetry by its greater variety of rhythm and its closer resemblance to the patterns of everyday speech. The word prose comes from the Latin prosa, meaning straightforward, hence the term "prosaic," which is often seen as pejorative.
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physical layer is level one in the seven-level OSI model of computer networking as well as in the five-layer TCP/IP reference model. It performs services requested by the data link layer.
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MITMOT ("Mac and mImo Technologies for More Throughput") proposal for IEEE 802.11n, the high throughput Wi-Fi MIMO standard has been initiated jointly by Motorola and Mitsubishi in order to propose a new PHY and MAC layer specification competing
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