l a service provider comes up with a compelling argument for Wi-Fi's per- formance superiority, the only companies that will make money on it will be those building wireless access points and routers. Worldwide Interoperability for Microwave Access (WiMAX) In April 2002, the IEEE published their 802.16 standard for broadband wireless access (BWA), also known as WiMAX. 802.16 specifies the details of the air interfaces for wireless metropolitan area networks (MANs). And while there are some similarities between Wi-Fi and WiMAX, in other respects they could not be more different. First of all, WiMAX was not created as a "goat trail" technology. Instead, developers first quietly created standards that were socialized through other stan- dards bodies such as the ITU-TSS. As a result of this strategy, spectrum was allocated globally for 802.16 implementation through a 2-year, open-consensus procedure that involved hundreds of engineers from major operators and vendors around the world. Consequently, 802.16, while still a nascent technology, enjoys global acceptance and what will be a relatively trivial implementation phase once it becomes more widely deployed. Furthermore, the capabilities of the standard are impressive. Whereas Wi-Fi offers megabits of nominal bandwidth over service distances of 300 feet, WiMAX offers 100 Mbps over a service radius of several miles. And because it is orthogonal, it does not require line of sight for connectivity. 802.16 is initially targeted at the "first mile" challenge for metropoli- tan area networks. It operates between 10 and 66 GHz (the 2 to 11 GHz spectrum with point-to-multipoint and optional mesh topologies) and defines a MAC layer that supports multiple physical layer specifica- tions specific to each frequency band. The 10 to 66 GHz standard sup- ports two-way transmission options at a variety of frequencies Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use 