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1.1.1 Narrowband Wireless Local-Loop Systems
Naturally, the first application for which a wireless alternative was developed and deployed was voice telephony. These systems, called wireless local-loop (WLL), were quite successful in developing countries such as China, India, Indonesia, Brazil, and Russia, whose high demand for basic telephone services could not be served using existing infrastructure. In fact, WLL systems based on the digital-enhanced cordless telephony (DECT) and code division multiple access (CDMA) standards continue to be deployed in these markets.
In markets in which a robust local-loop infrastructure already existed for voice telephony, WLL systems had to offer additional value to be competitive. Following the commercialization of the Internet in 1993, the demand for Internet-access services began to surge, and many saw providing high-speed Internet-access as a way for wireless systems to differentiate themselves. For example, in February 1997, AT&T announced that it had developed a wireless access system for the 1,900MHz PCS (personal communications services) band that could deliver two voice lines and a 128kbps data connection to subscribers. This system, developed under the code name "Project Angel," also had the distinction of being one of the first commercial wireless systems to use adaptive antenna technology. After field trials for a few years and a brief commercial offering, AT&T discontinued the service in December 2001, citing cost run-ups and poor take-rate as reasons.
During the same time, several small start-up companies focused solely on providing Internet-access services using wireless. These wireless Internet service provider (WISP) companies typically deployed systems in the license-exempt 900MHz and 2.4GHz bands. Most of these systems required antennas to be installed at the customer premises, either on rooftops or under the eaves of their buildings. Deployments were limited mostly to select neighborhoods and small towns. These early systems typically offered speeds up to a few hundred kilobits per second. Later evolutions of license-exempt systems were able to provide higher speeds.
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