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IEEE 802.16 Tutorial

In April 2002, the IEEE concluded a 2-year-long, open consensus process when it published the 802.16 standard. This standard is titled the "Air Interface for fixed Broadband Wireless Access Systems," and is also known as WirelessMAN (metropolitan area network). The standard addresses fixed wireless data networking over the range of miles or kilometers (a metropolitan area), as opposed to the more well-known and shorter range 802.11 standards, which operate over the range of hundreds of feet.

Fixed wireless has a history of providing quickly configured, low-cost data connections from point to point, often as a supplement to existing wireless networks. And, some see point-to-multipoint (also known as broadcast) MAN systems as a likely competitor to existing wired networks for consumer and business connectivity. Furthermore, the proliferation of WLAN hotspots has created a need for quick and cheap back-haul data services. The IEEE and others believe the existence of a MAN standard is an important component of a successful wireless market to meet those needs.

The 802.16 standard defines a medium access control (MAC) networking layer that supports a number of physical layer specifications. The multiple physical layer specifications are a reflection of the huge bandwidth covered by the standard: 10 to 66 GHz. The initial 802.16 standard was followed by several working groups, some of whom have released their amendments to the standard. Most prominent among the amendments is 802.16a, which extends the standard into the spectrum between 2 and 11 GHz.

The standards and groups of the 802.16 Working Group are:

802.16
The original standard, published in April 2002. This defines a MAC layer and several physical layer specifications. The MAC supports frequency-division-duplex (FDD) and time-division-duplex (TDD), as well as real-time adaptive modulation and coding. Single-carrier modulation. The high frequencies limit the use to line-of-sight. The physical layer of the standard covers the spectrum from 10 to 66 GHz, which includes the LMDS bands.

802.16a
A completed amendment that extends the physical layer to the 2 to 11GHz spectrum range (includes both licenses and unlicensed bands in the US).. The 802.16a standard also specifies three possible modulations: single carrier, 256 OFDM, and orthogonal frequency division multiple access (OFDMA). The lower frequencies make non-line of sight a possibility, which can also be helped by OFDM's ability to handle multipath signals. Range can be up to 30 miles, with typical cell footprints in the 4 to 6 mile range. Total data rate can be up to 100 Mb/s in each 20MHz channel. This extension is the focus of the WiMAX Forum.

802.16c
Profiles, conformance standards, and test suites for 802.16 (10-66GHz) implementations. The profiles are completed, but the conformance tests are still in development.

802.16d
System profiles for 802.16a (2-11GHz) implementations. Working group in progress.

802.16e
A nascent effort to extend the 802.16a standard for portability (mobile clients). Still very early in the process.

802.16.2
Recommended practices for MANs in the 10 to 66GHz spectrum to co-exist in the same geographic areas. Completed.

802.16.2a
Recommended practices for MANs in the 10 to 66GHz spectrum to co-exist in the same geographic areas. In progress.

Additional Information:*

IEEE 802.16 WirelessMAN Working Group
802.16 News

* The WAVE Report is not responsible for content on other sites.

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Page updated 1/24/07
Copyright 4th Wave Inc, 2007