Wireless Broadband Technologies: Wimax Standards, Wimax Technology
b. WiMAX standards
WiMAX technology is based on IEEE 802.16 . The IEEE standard serve as the basis for the WiMAX Forum's WiMAX air interface specifications at the PHY and MAC layers. Standards evolve through time to support new capabilities and to improve performance. There are three versions of the IEEE 802.16 standard that are key to the WiMAX Forum Certified program:
1. IEEE 802.16-2004 (or 802.16d): Based on Orthogonal Frequency Division Multiplexing (OFDM), it supports fixed and nomadic access. WiMAX Forum Certified equipment was certified for conformance only to this standard until mid-2008
2. IEEE 802.16e-2005 (or 802.16e). Based on Orthogonal Frequency Division Multiple Access (OFDMA), this standard version supports fixed and nomadic access, but it also includes additional capabilities to serve mobile access. The WiMAX Forum Certification program issued the first certifications for the 2.3GHz band in April 2008 and for the 2.5GHz band in June 2008
3. IEEE 802.16m: Currently under development, the new version of the standard will include improved mobile access and voice services and is a candidate for inclusion as one of the future ITU IMT-Advanced technologies. The WiMAX Forum is committed to preserving compatibility with the IEEE 802.16e-2005 standard, which will enable operators to roll out 802.16m-based equipment within their existing networks
On the basis of the IEEE 802.16 standard, the WiMAX Forum develops system profiles, which select a subset of capabilities included in the standard to define the capabilities that all WiMAX products are required to support. There are currently two system profiles: one for Fixed WiMAX (IEEE 802.16d) and one for Mobile WiMAX (IEEE 802.16e-2005). Additional capabilities may be added to the system profiles when a new version of the standard is approved.