igenda (i.e., fixing errors and minor updates) may need to be developed that offer minor revisions to the base standard. If there is a need to significantly update the base standard or any of its published amendments or corrigenda, the sponsor may consider the revision process. It is important to note that at the end of the five year validity period, an IEEE standard has to be revised, reaffirmed, or withdrawn. The development of the IEEE 802.16 standards, along with associated amendments and revi- sions, is the responsibility of the IEEE Working Group 802.16. The IEEE 802.16 Working Group is a member of the IEEE 802 group for Wireless Metropolitan Area Networks, in particular Part 16: Air Interface for Broadband Wireless Access Systems. The working group develops standards and recommended practices to support the development and deployment of fixed and mobile broadband wireless access systems. The IEEE 802.16 activities were initiated in August 1998. The Working Group's initial interest was the 10-66 GHz range. The 2-11 GHz amendment project that led to the IEEE 802.16a was approved in March 2000. The 802.16a project primarily involved the devel- opment of new physical layer specifications, with supporting enhancements to the basic data link layer. In addition, the Working Group completed the IEEE 802.16.2 standard (Recommended Practice for Coexistence of Fixed Broadband Wireless Access Systems) to address 10-66 GHz coexistence and, through the amendment, project 802.16.2a, expanded its recommendations to include licensed bands from 2 to 11 GHz. The mobility management capabilities were added to the Table 1-3 IEEE 802 Working Groups Working Group Charter and Scope Link to Resources Executive 802.1 Bridging and The IEEE 802.1 Working Group develops standards http://grouper.ieee.org/groups/ Committee (EC) Architecture and recommended practices in the areas of 802 LAN/ 802/1/ MAN architecture, internetworking among 802 LANs, MANs and other wide area networks, 802 Security, 802 overall network management, and protoc