Tuesday, May 5, 2009

Wireless broadband

Few WISPs provide download speeds of over 100 Mbit/s; most broadband wireless access services are estimated to have a range of 50 km (30 miles) from a tower.[1] Technologies used include LMDS and MMDS, as well as heavy use of the ISM bands and one particular access technology is being standardized by IEEE 802.16, also known as WiMAX. WiMAX is highly popular in Europe but has not met full acceptance in the United States because cost of deployment does not meet return on investment figures. In 2005 the Federal Communications Commission adopted a Report and Order that revised the FCC’s rules to open the 3650 MHz band for terrestrial wireless broadband operations.[2] On November 14, 2007 the Commission released Public Notice DA 07-4605 in which the Wireless Telecommunications Bureau announced the start date for licensing and registration process for the 3650-3700 MHz band.[3]

Initially, Wireless Internet Service Providers (WISPs) were only found in rural areas not covered by cable or DSL.[4] These early WISPs would employ a high-capacity T-carrier, such as a T1 or DS3 connection, and then broadcast the signal from a high elevation, such as at the top of a water tower. To receive this type of Internet connection, consumers mount a small dish to the roof of their home or office and point it to the transmitter. Line of sight is usually necessary for WISPs operating in the 2.4 and 5GHz bands with 900MHz offering better NLOS performance.

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