This article is about wireless networking in general. For local area network technologies, see Wireless LAN.
Three fixed wireless dishes with protective covers on top of 307 W. 7th Street, Fort Worth, Texas around 2001
Wireless broadband is telecommunications technology that provides high-speed wireless Internet access or computer networking access over a wide area. The term comprises both fixed and mobile broadband.
Contents
1The term broadband
2Technology and speeds
3Development of Wireless Broadband in the United States
3.1Residential Wireless Internet
3.2Business Wireless Internet
3.3Demand for spectrum
4Mobile wireless broadband
5Licensing
6See also
7References
8External links
The term broadband[edit]
Originally the word "broadband" had a technical meaning, but became a marketing term for any kind of relatively high-speed computer network or Internet access technology. According to the 802.16-2004 standard, broadband means "having instantaneous bandwidths greater than 1 MHz and supporting data rates greater than about 1.5 Mbit/s."[1] The Federal Communications Commission (FCC) recently re-defined the definition to mean download speeds of at least 25 Mbit/s and upload speeds of at least 3 Mbit/s.[2]
Technology and speeds[edit]
A typical WISP Customer Premises Equipment (CPE) installed on a residence
A wireless broadband network is an outdoor fixed and/or mobile wireless network providing point-to-multipoint or point-to-point terrestrial wireless links for broadband services.
Wireless networks can feature data rates exceeding 1 Gbit/s.[3] Many fixed wireless networks are exclusively half-duplex (HDX), however, some licensed and unlicensed systems can also operate at full-duplex (FDX)[4] allowing communication in both directions simultaneously.
Outdoor fixed wireless broadband networks commonly utilize a priority TDMA based protocol[5][6][7][8] in order to divide communication into timeslots. This timeslot technique eliminates many of the issues common to 802.11 Wi-Fi protocol in outdoor networks such as the hidden node problem.
Few wireless Internet service providers (WISPs) provide download speeds of over 100 Mbit/s; most broadband wireless access (BWA) services are estimated to have a range of 50 km (31 mi) from a tower.[9] Technologies used include Local Multipoint Distribution Service (LMDS) and Multichannel Multipoint Distribution Service (MMDS), as well as heavy use of the industrial, scientific and medical (ISM) radio bands and one particular access technology was standardized by IEEE 802.16, with products known as WiMAX.[10]
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.[10]
Another system that is popular with cable internet service providers uses point-to-multipoint wireless links that extend the existing wired network using a transparent radio connection. This allows the same DOCSIS modems to be used for both wired and wireless customers.[11]
Development of Wireless Broadband in the United States[edit]
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.[12] In 2010 the FCC adopted the TV White Space Rules (TVWS) and allowed some of the better no line of sight frequency (700 MHz) into the FCC Part-15 Rules.[13] The Wireless Internet Service Providers Association, a national association of WISPs, petitioned the FCC and won.[14]
Initially, WISPs were only found in rural areas not covered by cable or DSL.[15] 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 5 GHz bands with 900 MHz offering better NLOS (non-line-of-sight) performance.
Do'stlaringiz bilan baham: |