Fixed wireless is a method of transmission of high speed data traffic via a wireless connection between two fixed points. Subscriber service consists of a microwave antenna and radio on customer's rooftop for transmitting and receiving RF signals. The customer's antenna points to the service provider's RF transceiver (Access Point) located on the radio tower or tall building. Fixed wireless connection with customer has clear Line of Sight (LOS) to the Access Point can reach distance up to 50 miles and data rate up to hundreds of Mbps.
Fixed Wireless has two configurations, point-to-point (PtP) or point-to-multipoint (PtMP). PtP networking connects two locations by using two radios and two antennas dedicated to only each other. PtMP networking refers to communications between one access point and multiple customer radios. Fixed wireless can use frequency either in licensed band or unlicensed band. Unlicensed band frequencies of 900MHz (902-928), 2.4GHz, 5.3GHz, 5.4GHz, 5.8GHz, 24GHz, and 60GHz are exempt from FCC licensing requirement. Unlicensed wireless systems, although quick to deploy, do not promise exclusive use of the band and are susceptible to potential interference. Licensed microwave wireless systems operate within parts of the radio spectrum (VHF, 900MHz, 2GHz, 3.65GHz, 4.9GHz, 6GHz, 7GHz, 11GHz, 13GHz, 18GHz, 23GHz, and 80GHz) designated by the FCC. To operate a licensed microwave fixed wireless radio system, one must apply for a license from the FCC. Licensed operators are permitted exclusive use of part of the band over an assigned geographic area.
Fixed Wireless Broadband is designed to emulate coaxial cable connection and support both TDM and packet traffic such as T1, T3, frame relay, Ethernet and ATM. High-capacity carrier-grade wireless backhaul radio combines TDM with Ethernet to provide smooth evolution to advanced, packet-based radio performance and facilitating cost effective, risk-free migration to IP/Ethernet. Enhanced Fixed Wireless can deliver Internet, Voice and MPLS, all with guaranteed Service Level Agreements. The advantages of fixed wireless include lower costs, greater flexibility, and faster deployment. Reliability is on a par with wireline networks and can be engineered to achieve 99.999% availability. Service carriers go to great lengths to ensure secure data transmission through the use of high-gain directional antennas tightly focusing the signal and directing it precisely at the customer's CPE. Fixed Wireless Broadband transmits and receives encrypted signals from specific, authenticated devices only. It employs the Advanced Encryption Standard (AES), which is the standard adopted by the U.S. government to protect its data. Hence, fixed-wireless data transmission using AES are as secure as any transmission in the world.
Latest technology innovation has made fixed wireless a competitive mode of broadband delivery in increasingly high density environments such as the suburban, urban, and enterprise customers. Multiple Input Multiple Output or MIMO technology has enabled the rapid growth in bandwidth capacity by continually improving spectrum efficiency with the addition of more and more MIMO streams and smart antenna array technologies. Antenna beamforming is a crucial technology enabling the spectrum used by an access point to be reused by multiple clients simultaneously. Beamforming uses precise geoposition information from each wireless client to focus wireless antenna transmit signals towards each unique client, achieving improved focused wireless signals, and significantly reducing interference in the spectrum. Because beamforming isolates client signals, it creates spatial opportunities in the spectrum for additional MIMO streams to be used simultaneously using SDMA (Space Division Multiple Access). This is called Multi-User (MU-) MIMO. When downstream traffic arrives for multiple clients, the access point identifies geolocation based beamforming opportunities to service those clients simultaneously, drastically improves the capacity of the radios. MU-MINO enables fixed wireless to deliver fiberlike broadband connectivity at a fraction of the cost of traditional wireline solutions, in any environment, from low-density rural broadband to high-capacity, high-reliability business connectivity for the enterprise.
Paul Ngai, P.E. is a telecom consultant specialized in
RF and Fiber Optic Networks. He is also the principal of Network Systems Technologies LLC
http://www.nstecs.net, a telecommunications consulting firm provides planning, analysis, design, testing and operation support services.
