n 10 Gbps, which means that any local loop solution that operates slower than any of those poses a restrictive barrier to the overall performance of the system. LMDS offers a good alternative to wired options. Originally offered as Cellular Vision, it was seen by its inventor, Bernard Bossard, as a way to provide cellular television as an alternative to cable. It is, in effect, wireless DSL. Operating in the 28 GHz range, LMDS offers data rates as high as 155 Mbps, the equivalent of SONET OC-3c. Because it is a wireless solution, it requires minimal infrastructure and can be deployed quickly and cost effectively as an alternative to the wired infrastructure provided by incumbent service providers. After all, the highest cost component when building networks is not the distribution facility, but rather the labor required to trench it into the ground or build aerial facilities. Thus, any access alternative that minimizes the cost of labor will garner significant attention. LMDS relies on a cellular-like deployment strategy under which the cells are approximately three miles in diameter. Unlike cellular service, however, users are stationary. Consequently there is no need for LMDS cells to support roaming. Antenna/transceiver units are generally placed on rooftops as they need unobstructed line of sight to operate properly. In fact, this is one of the disadvantages of LMDS (and a number of other Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. Access Technologies Chapter 6 wireless technologies): Besides suffering from unexpected physical obstructions, the service suffers from "rain fade" caused by absorption and scattering of the transmitted microwave signal because of atmos- pheric moisture. Even some forms of foliage will cause interference for LMDS, so the transmission and reception equipment must be mounted high enough to avoid such obstacl