s solution to supplement xDSL and cable modems in delivering broadband access to homes and small businesses. A wireless solution for "last mile" broadband access has the advantage of being able to provide wide geographical coverage with minimal infrastructure cost, and therefore brings with it the potential to accelerate broadband uptake. The evolving suite of IEEE 802.16 standards is shown in Table 12-1. The 10-66 GHz frequency range was the initial focus of the IEEE Working Group on broadband wireless access (BWA) which developed the standards. This was largely motivated by worldwide spectrum availability in this frequency range, and led to the approval of the initial IEEE 802.16 standard in 2001 and its publication in March 2002. The Working Group then turned its attention to the 2-11 GHz range, where the advantages of lower cost implementation and non line-of-sight transmission outweighed the potential difficulties in this crowded piece of RF spectrum. The result was the IEEE 802.16a standard, approved in 2002 and published in January 2003. IEEE 802.16 has been designed to offer considerable flexibility in the specification of the PHY layer, in order to accommodate varying requirements (such as channel widths) in different regulatory regimes. Chapter Twelve Table 12-1: The IEEE 802.16 Standard Suite Standard Key features 802.16 Original standard, approved in 2001. 10-66 GHz spectrum, line-of-sight links up to 134 Mbps. 802.16a Approved in 2002. 2-11 GHz. Non line-of-sight links up to 70 Mbps. 802.16b Update to 802.16a dealing with unlicensed applications in the 5 GHz band. 802.16c Update to 802.16 addressing interoperability of 10-66 GHz systems. 802.16d The basis of "WiMAX", replaces 802.16a and includes support for advanced antenna systems (MIMO). Approved in June 2004 as 802.16-2004. 802.16e Extension to provide mobility, including rapid adaptation to the changing propagation environment. 802.16f Extension to support multi-hop capabilities required for mesh networking. 802.16g Addresses efficient handover 