 to data networking standards. ArrayComm is working to standardize the remaining components, espe- cially the air interface, through the IEEE 802.20 Working Group. The air interface combines smart antenna techniques with industry best practices for wireless data, including adaptive modulation, fast ARQ, and a QoS-cognizant scheduler, to create a high-performance, reliable, and high-capacity data delivery mechanism. In most respects, iBurst appears to most closely align itself-with respect to factors such as bandwidth, distance covered, and cost-with 3G+ technology. However, it works on current 2.5G platforms, and it can extend the life of these platforms, resulting in substantial cost savings. Chapter 15 WMANs, WLANs, and WPANs Flash-OFDM Flarion, which was acquired by Qualcomm (www.qualcomm.com), developed a variant of 802.20 called Flash-OFDM. Flash-OFDM (which stands for Fast Low- Latency Access with Seamless Handoff OFDM) uses a technique called fast hop- ping, a new signal-processing scheme that supports high data rates with very low packet and delay losses (i.e., latencies) over a distributed all-IP wireless network. OFDM is nothing new; its core multiplexing principles have been applied to everything from satellite broadcast to ADSL. It has played a critical role in wireless, forming the basis of the IEEE 802.11a standard, and a crucial role in the WiMax Forum's multiplexing scheme. Lucent Technologies (www.lucent.com) modified OFDM by improving the signal-processing scheme and adding other improvements. To further this research and development and to commercialize the enhanced OFDM, Lucent formed Flarion Technologies in 2000. Because Flash-OFDM is not compatible with 2.5G or 3G technology, the business model requires carriers to move in a new direction. Flarion's argument is that conventional wireless systems, including 3G, have been designed primarily at the physical layer. But mobile users, demanding very high-speed applications, require new air interfaces at all protocol layers, including the MAC, data