o whatever will be deployed in the 2010-2015 time frame. The introduction of 3G technology provides a huge expansion in mobile capacity and bandwidth. 4G will do the same for the spectrum of broadband com- munications. By supporting mobility, and by being faster and cheaper to deploy, it is expected that 4G will disrupt today's wired broadband access alternatives, including DSL and cable modems. 4G is also expected to serve the next billion 4G: Wireless Broadband Web users in developing countries. Generally speaking, 4G is an evolution not only to move beyond the limitations and problems associated with 3G but also increase the bandwidth, enhance the quality of services, and reduce the cost of the resource. The main distinguishing characteristics between 3G and 4G will be increased data rates, enhanced multimedia services, new transmission techniques, new Internet access technology, greater compatibility in interfacing with wired backbone networks, and the addition of QoS and security mechanisms. 4G should also be able to provide smooth global roaming ubiquitously, at lower cost. At the very least, this means a new air interface supporting higher data rates and also a change in the way data transport is handled end to end. Unlike 3G networks, which are a mix of circuit-switched and packet-switched networks, 4G will be based solely on packet switching. The major telecommunications players are already lining up behind their picks for success in the next generation. Intel (www.intel.com), working with startup Beceem Communications, Inc. (www.beceem.com), will begin putting WiMax sili- con in notebooks starting in 2007, while Qualcomm (www.qualcomm.com) is expected to put the Flash-OFDM technology in handset chips. Sprint Nextel (www.sprint.com) is studying both technologies, as well as options on the CDMA and GSM roadmaps, as it plans to upgrade its CDMA cellular network in 2008 to 3Mbps in an attempt to compete with DSL and cable. Sprint Nextel conducted one successful trial of the Flash-OFDM technology in 2005 and