The market for broadband communications is growing rapidly, and the potential applications and services are numerous and diverse. Several technologies are currently being developed to offer such services. Both wired and wireless system solutions aim to win a share of the market. The wired contenders include digital subscriber lines (xDSL), cable modems and others. The wireless contenders include satellite communications systems, stratospheric communications systems, and terrestrial communications systems, specifically, Multipoint Multichannel Distribution Service (MMDS) and Local Multipoint Distribution Service (LMDS). While these systems do not all target identical market segments, the likely markets do overlap. The various broadband wireless access systems compete therefore more against high-speed wired solutions than against each other. Table III-1 from Allied Business Intelligence, Inc. presents a forecast of market share for various high-speed communication solutions [BWS1]. This forecast projects that wired technologies would command about 75 % of subscribers in the year 2003.
Broadband Subscribers by Technology, US Market, 2003
(source Allied Business Intelligence, Inc.)
ADSL 36 %
Cable Modem 26 %
ISDN 12 %
Satellite 12 %
LMDS 9 %
Others 5 %
A. Terrestrial Broadband Wireless Systems
A common way to classify broadband terrestrial, wireless fixed communications systems is to call systems using frequencies below 10 GHz MMDS systems and to call systems using frequencies above 10 GHz LMDS systems. The motivation for this classification is that the propagation characteristics are quite different at say 30 GHz than at 5 GHz. Equipment and components for frequencies under 10 GHz are mature, while equipment at higher frequencies is based on technology that still is relatively new and expensive. Systems at frequencies above 20 GHz are for fixed users. Systems below 10 GHz are also for fixed users, but may evolve to serve mobile users.
