Tuesday, May 6, 2008

IEEE 802.16 and WiMAX

The IEEE 802.16 group was formed in 1998 to develop an air-interface standard for wireless broadband. The group’s initial focus was the development of a Line-Of-Sight (LOS)-based point-to-multipoint wireless broadband system for operation in the 10GHz–66GHz millimeter wave band. The resulting standard—the original 802.16 standard, completed in December 2001—was based on a single-carrier PHY layer with a burst Time Division Multiplexed (TDM) Media Access Control (MAC) layer. The IEEE 802.16 group subsequently produced 802.16a, an amendment to the standard, to include NLOS applications in the 2GHz–11GHz band, using an Orthogonal Frequency Division Multiplexing (OFDM)-based PHY layer. Further revisions resulted in a new standard in 2004, called IEEE 802.16d-2004, which replaced all prior versions and formed the basis for the first WiMAX solution. In December 2005, the IEEE group completed and approved IEEE 802.16e-2005, an amendment to the IEEE 802.16d-2004 standard that added mobility support. Currently, the WiMAX Forum has two different system profiles:

one based on IEEE 802.16d-2004, OFDM PHY, called the fixed system profile; the other one based on IEEE 802.16e-2005 scalable OFDMA PHY, called the mobility system profile

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