The term base station can be used in the context of land surveying, wireless computer networking, and wireless communications.

Land surveying

In the context of land surveying, a base station is a GPS receiver at an accurately-known fixed location which is used to derive correction information for nearby portable GPS receivers. This correction data allows propagation and other effects to be corrected out of the position data obtained by the mobile stations, which gives greatly increased location precision and accuracy over the results obtained by uncorrected GPS receivers. Over fifty GPS satellites such as this NAVSTAR have been launched since 1978. ... Radio propagation is a term used to explain how radio waves behave when they are transmitted, or are propagated from one point on the Earth to another. ...

Computer networking

In the area of wireless computer networking, a base station is a radio receiver/transmitter that serves as the hub of the local wireless network, and may also be the gateway between a wired network and the wireless network. It typically consists of a low-power transmitter and wireless router. This article may be too technical for most readers to understand. ...

See also

• Access point base station
• IEEE 802.11
• Signal strength

An Access Point Base Station - sometimes called a femtocell, is a scalable, multi-channel, two-way communication device extending a typical base station by incorporating all of the major components of the telecommunications infrastructure. ... IEEE 802. ... In telecommunications, and particularly in radio, signal strength is the measure of how strongly a transmitted signal is being received, measured, or predicted, at a reference point that is a significant distance from the transmitting antenna. ...

Wireless communications

In radio communications, a base station is a wireless communications station installed at a fixed location and used to communicate as part of either:

• a push-to-talk two-way radio system, or;
• a wireless telephone system such as cellular CDMA or European GSM.

Push-to-Talk (PTT), also known as Press-to-Transmit, is a method of conversing on half-duplex communication lines, including two-way radio, using a momentary button to switch from voice reception mode to transmit mode. ... A two-way radio is simply a radio that can both transmit and receive (a transceiver). ... A radiotelephone is a communications device that allows two or more people to talk using radio. ... Cellular redirects here. ... General Information Generically (as a multiplexing scheme), code division multiple access (CDMA) is any use of any form of spread spectrum by multiple transmitters to send to the same receiver on the same frequency channel at the same time without harmful interference. ... Not to be confused with Get Some Mates The Global System for Mobile Communications (GSM) is the most popular standard for mobile phones in the world. ...

Base station images

Two GSM mobile phone base station towers disguised as trees in Dublin, Ireland. Image File history File linksMetadata Download high resolution version (2045x1363, 573 KB) Summary Two GSM base stations disguised as trees in Dublin, Ireland. ... Not to be confused with Get Some Mates The Global System for Mobile Communications (GSM) is the most popular standard for mobile phones in the world. ... It has been suggested that this article or section be merged with Tree (disambiguation). ... WGS-84 (GPS) Coordinates: 53. ...	A base station disguised as a palm tree in Tucson, Arizona. Image File history File linksMetadata Size of this preview: 418 × 599 pixel Image in higher resolution (766 × 1098 pixel, file size: 545 KB, MIME type: image/jpeg) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Base station Cell... Genera Many; see list of Arecaceae genera Arecaceae (also known as Palmae or Palmaceae), the palm family, is a family of flowering plants, belonging to the monocot order Arecales. ... Nickname: The Old Pueblo Location in Pima County and the state of Arizona Coordinates: Country United States State Arizona Counties Pima Mayor Bob Walkup (R) Area    - City 505. ... Official language(s) English Capital Phoenix Largest city Phoenix Area  Ranked 6th  - Total 113,998 sq mi (295,254 km²)  - Width 310 miles (500 km)  - Length 400 miles (645 km)  - % water 0. ...	Close-up of a base station antenna in Mexico City, Mexico. There are three antennaInsert non-formatted text here#REDIRECT Insert text#REDIRECT Insert texts: each serves a 120-degree segment of the horizon. The microwave dish links the site with the telephone network. Image File history File linksMetadata Download high resolution version (1920x2560, 543 KB) Summary Base station in Pabellón Bosques shopping center, Mexico City, Mexico. ... Nickname: Ciudad de los Palacios Location of Mexico City in central Mexico Coordinates: Country Mexico Federal entity Federal District Boroughs The 16 delegaciones Founded (as Tenochtitlan) c. ... Category: ... Category: ...	A typical consumer-grade CB base station. Image File history File linksMetadata Download high-resolution version (977x633, 296 KB) This is my own work. ...
A professional rack-mount iDEN Base Radio at a Cell Site. Image File history File linksMetadata Iden. ... Iden is also a village in East sussex, England iDEN Base Radio at a Cell Site Integrated Digital Enhanced Network (iDEN) is a mobile telecommunications technology, it is known to eat little children, developed by Motorola, which provides its users the benefits of a trunked radio and a cellular telephone. ...	Trunked systems have groups of base stations configured as repeaters. The center blocks with frequencies in this trunked =jmjm block diagram each represents a base station. Image File history File links Size of this preview: 450 × 599 pixel Image in higher resolution (759 × 1010 pixel, file size: 42 KB, MIME type: image/png) Please credit David Jordan when using this image. ... A trunked radio system is a radio system used to maximize available capacity in a two-way radio system, usually UHF. Groups of users are given a logical talkgroup to share for their communications, rather than a dedicated radio frequency. ... A Radio Repeater is a combination of a radio receiver and a radio transmitter that receives a weak or low-level signal and retransmits it at a higher level or higher power, so that the signal can cover longer distances without degradation. ... A block diagram is a pictorial representation of some process or model of a complex system. ...

Two-way radio

Professional

In professional two-way radio systems, a base station is used to maintain contact with a dispatch fleet of hand-held or mobile radios, and/or to activate one-way paging receivers. The base station is one end of a communications link. The other end is a movable vehicle-mounted radio or walkie-talkie.^[1] Examples of base station uses in two-way radio include the dispatch of tow trucks and taxicabs. Dispatch is a procedure for assigning customers to taxicabs, couriers, emergency services, and other mobile units. ... Recreational, toy and amateur radio walkie talkies A walkie-talkie or two-way radio is a hand-held portable, bi-directional radio transceiver. ... It has been suggested that this article or section be merged with Mobile radio telephone. ... Heavy Tow truck A tow truck (also called a wrecker, a breakdown truck or a breakdown lorry), is a vehicle used to take disabled motor vehicles off a roadway to another location in case of breakdown or collision, or to impound illegally parked vehicles on public or (more commonly) private... Taxicab, short forms taxi or cab, is a type of public transport for a single passenger, or small group of passengers, typically for a non-shared ride. ...

Basic base station elements used in a remote-controlled installation. Selective calling options such as CTCSS are optional.

Professional base station radios are often one channel. In lightly-used base stations, a multi-channel unit may be employed.^[2] In heavily-used systems, the capability for additional channels, where needed, is accomplished by installing an additional base station for each channel. Each base station appears as a single channel on the dispatch center control console. In a properly designed dispatch center with several staff members, this allows each dispatcher to communicate simultaneously, independently of one another, on a different channel as necessary. For example, a taxi company dispatch center may have one base station on a high-rise building in Boston and another on a different channel in Providence. Each taxi dispatcher could communicate with taxis in either Boston or Providence by selecting the respective base station on his or her console.^[3] Image File history File links Size of this preview: 800 × 344 pixel Image in higher resolution (2000 × 860 pixel, file size: 104 KB, MIME type: image/png) Block diagram is from: Figure 2: Two Channel VHF Base Station, Planning Emergency Medical Communications: Volume 2, Local/Regional Level Planning Guide, (Washington... Image File history File links Size of this preview: 800 × 344 pixel Image in higher resolution (2000 × 860 pixel, file size: 104 KB, MIME type: image/png) Block diagram is from: Figure 2: Two Channel VHF Base Station, Planning Emergency Medical Communications: Volume 2, Local/Regional Level Planning Guide, (Washington... In a conventional, analog two-way radio system, a standard radio has noise squelch or carrier squelch which allows a radio to receive all transmissions on a channel. ... Nickname: City on the Hill, Beantown, Athens of America, The Hub (of the Universe)1 Location in Massachusetts, USA Coordinates: Country United States State Massachusetts County Suffolk County Government  - Mayor Thomas M. Menino (D) Area  - City  89. ... Nickname: Beehive of Industry, The Renaissance City, The Divine City Location in Rhode Island Coordinates: Country United States State Rhode Island County Providence Government  - Mayor David N. Cicilline (D) Area  - City  20. ...

In dispatching centers it is common for eight or more radio base stations to be connected to a single dispatching console. Dispatching personnel can tell which channel a message is being received on by a combination of local protocol, unit identifiers, volume settings, and busy indicator lights. A typical console has two speakers identified as select and unselect. Audio from a primary selected channel is routed to the select speaker and to a headset. Each channel has a busy light which flashes when someone talks on the associated channel.^[4]

Base stations can be local controlled or remote controlled. Local controlled base stations are operated by front panel controls on the base station cabinet. Remote control base stations can be operated over tone- or DC-remote circuits. The dispatch point console and remote base station are connected by leased private line telephone circuits, (sometimes called RTO circuits), a DS-1, or radio links.^[5] The consoles multiplex transmit commands onto remote control circuits. Some system configurations require duplex, or four wire, audio paths from the base station to the console. Others require only a two-wire or half duplex link.^[6] 4-20 ma is an analog electrical transmission standard for industrial instrumentation. ... ...

The diagram shows a band-pass filter used to reduce the base station receiver's exposure to unwanted signals. It also reduces the transmission of undesired signals. The isolator is a one-way device which reduces the ease of signals from nearby transmitters going up the antenna line and into the base station transmitter. This prevents the unwanted mixing of signals inside the base station transmitter which can generate interference.

Interference could be defined as receiving any signal other than from a radio in your own system. To avoid interference from users on the same channel, or interference from nearby strong signals on another channel, professional base stations use a combination of:^{[7] [8]} Image File history File links Size of this preview: 696 × 600 pixel Image in higher resolution (4824 × 4158 pixel, file size: 1. ... Image File history File links Size of this preview: 696 × 600 pixel Image in higher resolution (4824 × 4158 pixel, file size: 1. ... The frequency axis of this symbolic diagram would be logarithmically scaled. ... The word receiver has a number of different meanings: In communications and information processing, a receiver is the recipient (observer) of a message (information), which is sent from a source (object). ... In telecommunication, the term circulator has the following meanings: 1. ... Antenna tower of Crystal Palace transmitter, London A transmitter (sometimes abbreviated XMTR) is an electronic device which with the aid of an antenna propagates an electromagnetic signal such as radio, television, or other telecommunications. ...

• minimum receiver specifications and filtering.^[9][10][11]
• analysis of other frequencies in use nearby.
• in the US, coordination of shared frequencies by coordinating agencies.^[12]
• locating equipment so that terrain blocks interfering signals.
• use of directional antennas to reduce unwanted signals.

Base stations are sometimes called control or fixed stations in US Federal Communications Commission licensing. These terms are defined in regulations inside Part 90 of the commissions regulations. In US licensing jargon, types of base stations include: The FCCs official seal. ...

• A fixed station is a base station used in a system intended only to communicate with other base stations. A fixed station can also be radio link used to operate a distant base station by remote control. (No mobile or hand-held radios are involved in the system.)
• A control station is a base station used in a system with a repeater where the base station is used to communicate through the repeater.
• A temporary base is a base station used in one location for less than a year.
• A repeater is a type of base station that extends the range of hand-held and mobile radios.

A Radio Repeater is a combination of a radio receiver and a radio transmitter that receives a weak or low-level signal and retransmits it at a higher level or higher power, so that the signal can cover longer distances without degradation. ...

Amateur and hobby

In Amateur radio, a base station also communicates with mobile rigs but for hobby or family communications. Amateur systems sometimes serve as dispatch radio systems during disasters, search and rescue mobilizations, or other emergencies. Ham radio station with modern solid-state transceiver featuring LCD display and DSP capabilities Ham radio station with vintage vacuum tube gear featuring separate transmitter, receiver and power supply Amateur radio, often called Ham radio, is a hobby and public service enjoyed by about 6 million people throughout the world. ... Mobile surveillance camera watching over passengers in a taxicab A mobile rig (or automobile rig) is a class of communications system that is midway between a base station (building-mounted) and portable (body mounted). ...

An Australian UHF CB base station is another example of part of a system used for hobby or family communications. UHF CB is a licence-free citizens band radio service authorised by the government of Australia in the UHF 477MHz band. ...

Wireless telephone

Wireless telephone differ from two-way radios in that: A radiotelephone is a communications device that allows two or more people to talk using radio. ...

• wireless telephones are circuit switched: the communications paths are set up by dialing at the start of a call and the path remains in place until one of the callers hangs up.
• wireless telephones communicate with other telephones usually over the public switched telephone network.

A wireless telephone base station communicates with a mobile or hand-held phone. For example, in a wireless telephone system, the signals from one or more mobile telephones in an area are received at a nearby base station, which then connects the call to the land-line network. Other equipment is involved depending on the system architecture. Mobile telephone provider networks, such as European GSM networks, may involve carrier, microwave radio, and switching facilities to connect the call. In the case of a portable phone such as a US cordless phone, the connection is directly connected to a wired land line. It has been suggested that Office classification be merged into this article or section. ... In telecommunications, multiplexing (also muxing or MUXing) is the combining of two or more information channels onto a common transmission medium using hardware called a multiplexer or (MUX). ... This article or section does not cite its references or sources. ... A telephone operator manually connecting calls with patch cables at a telephone switchboard. ...

Emissions issues

While low levels of radio-frequency power are usually considered to have negligible effects on health, national and local regulations restrict the design of base stations to limit exposure to electromagnetic fields. Technical measures to limit exposure include restricting the radio frequency power emitted by the station, elevating the antenna above ground level, changes to the antenna pattern, and barriers to foot or road traffic. For typical base stations, significant electromagnetic energy is only emitted at the antenna, not along the length of the antenna tower. This article or section may be confusing or unclear for some readers, and should be edited to rectify this. ... A Yagi-Uda beam antenna Short Wave Curtain Antenna (Moosbrunn, Austria) A building rooftop supporting numerous dish and sectored mobile telecommunications antennas (Doncaster, Victoria, Australia) An antenna or aerial is an arrangement of aerial electrical conductors designed to transmit or receive radio waves which is a class of electromagnetic waves. ...

Because mobile phones and their base stations are two-way radios, they produce radio-frequency (RF) radiation (that's how they communicate), and they expose people near them to RF radiation giving concerns about mobile phone radiation and health. Hand-held mobile telephones are relatively low power so the RF radiation exposures from them are generally low. It has been suggested that this article or section be merged with Radio waves. ... Electromagnetic radiation or EM radiation is a combination (cross product) of oscillating electric and magnetic fields perpendicular to each other, moving through space as a wave, effectively transporting energy and momentum. ... A Greenfield-type tower used in base stations for mobile telephony A modern mobile phone (Samsung) Mobile phone radiation and health concerns have been raised, especially following the enormous increase in the use of wireless mobile telephony throughout the world (as of August 2005, there were more than 2 billion...

The consensus of the scientific community is that the power from these mobile phone base station antennas is too low to produce health hazards as long as people are kept away from direct access to the antennas. However, current international exposure guidelines (INCIRP) are based largely on the thermal effects of base station emissions. Some scientists have questioned whether there are non thermal effects from being exposed to low level RF such as are transmitted from mobile phone base stations. Such 'non-thermal' effects include how the actual frequencies interfere with the human brain and all other cells in the human body. Sources for consideration can be found here. In animals the brain, or encephalon (Greek for in the head), is the control center of the central nervous system, responsible for thought. ...

See also

• Base Transceiver Station
• Base Station Controller
• Mobile Switching Center
• Macrocell
• Microcell
• Picocell
• Femtocell
• Access point base station
• Cell site
• Cellular repeater
• Mobile phone
• Mobile phone radiation and health
• Portable phone
• Signal strength
• Audio level compression

A typical BTS tower which holds the antenna. ... The Base Station Subsystem (BSS) is the section of a GSM network which is responsible for transmitting to and receiving radio signals from the mobile phone. ... The GSM Core network is the heart of a GSM system, the most common mobile phone system in the world. ... Microcell Telecommunications is a Canadian wireless PCS telecommunications service provider. ... A Picocell is wireless communication system typically covering a small area, such as in-building (offices, shopping malls, train stations, etc. ... An Access Point Base Station - sometimes called a femtocell, is a scalable, multi-channel, two-way communication device extending a typical base station by incorporating all of the major components of the telecommunications infrastructure. ... An Access Point Base Station - sometimes called a femtocell, is a scalable, multi-channel, two-way communication device extending a typical base station by incorporating all of the major components of the telecommunications infrastructure. ... A cell site is a site where a wireless antenna and network communications equipment are placed to create the network cells for the use of mobile phones. ... A compact cellular repeater including a directiona antenna, an amplifier and a monopole rebroadcast antenna. ... A Greenfield-type tower used in base stations for mobile telephony A modern mobile phone (Samsung) Mobile phone radiation and health concerns have been raised, especially following the enormous increase in the use of wireless mobile telephony throughout the world (as of August 2005, there were more than 2 billion... A portable phone or cordless phone is a wireless telephone which is associated with a fixed telephone landline (POTS) and can only be operated close to (typically less than 100 metres of) its base station, such as in and around the house. ... In telecommunications, and particularly in radio, signal strength is the measure of how strongly a transmitted signal is being received, measured, or predicted, at a reference point that is a significant distance from the transmitting antenna. ... Audio level compression, also called dynamic range compression, volume compression, compression, limiting, or DRC (often seen in DVD player settings) is a process that manipulates the dynamic range of an audio signal. ...

Notes

1. ^ "Evaluating Regional Alternatives: Systems Design Considerations," Planning Emergency Medical Communications: Volume 2, Local/Regional Level Planning Guide, (Washington, D.C.: National Highway Traffic Safety Administration, US Department of Transportation, 1995) pp. 39-43.
2. ^ Block diagram is from: "Figure 2: Two Channel VHF Base Station," Planning Emergency Medical Communications: Volume 2, Local/Regional Level Planning Guide, (Washington, D.C.: National Highway Traffic Safety Administration, US Department of Transportation, 1995) pp. 42.
3. ^ Base stations in land mobile systems are often located at remote sites such as hilltops or water towers. Some are controlled from two or more locations. For example, a base station used to communicate with taxis may be connected to remote control consoles at both a taxi company office and an answering service for after-hours calls. The taxi company and answering service may be miles apart. Single channel base stations reduce confusion by eliminating the possibility that the wrong channel may be selected.
4. ^ To read more about multi-channel consoles, look at the service manual for a relatively simple console: 8-Channel Remote Console, 120, 220, 240 V AC or 12 V DC T16167 AM or BM, 68-81021E80, (Schaumburg, Illinois: Motorola, Inc. 1980.) This is a relatively simple analog console compared to large, enterprise-level Centracom-series units.
5. ^ The term RTO circuit is legacy jargon and comes from Bell System billing terminology. RTO circuits refer to analog radio remote control and radio broadcast leased telephone circuits.
6. ^ For a brief discussion of remote controlled base stations, see: "Evaluating Regional Alternatives: Systems Design Considerations," Planning Emergency Medical Communications: Volume 2, Local/Regional Level Planning Guide, (Washington, D.C.: National Highway Traffic Safety Administration, US Department of Transportation, 1995) pp. 39-41. Tone remote controls are described in this section.
7. ^ Block diagram is from: "Figure 8: Bandpass Cavity/Isolator Location," Planning Emergency Medical Communications: Volume 2, Local/Regional Level Planning Guide, (Washington, D.C.: National Highway Traffic Safety Administration, US Department of Transportation, 1995) pp. 57.
8. ^ Bulleted items condensed from, "EMS Communications," "System Coordination," and "Site Engineering," in Planning Emergency Medical Communications: Volume 2, Local/Regional Level Planning Guide, (Washington, D.C.: National Highway Traffic Safety Administration, US Department of Transportation, 1995) pp. 10-19, 55-58.
9. ^ For an example of receiver specifications, see, "Table 9-3," 800 MHz Trunked Radio Request for Proposals: Public Safety Projects Office, (Oklahoma City, Oklahoma: Oklahoma City Municipal Facilities Authority, 2000, pp. 181.
10. ^ A list of types of filtering used to prevent interference between equipment at the same site is included in "6.2.4 Electromagnetic Compatibility Studies," 800 MHz Trunked Radio Request for Proposals: Public Safety Projects Office, (Oklahoma City, Oklahoma: Oklahoma City Municipal Facilities Authority, 2000, pp. 119.
11. ^ More detail of interference reduction equipment is provided in, "9.1.2 Base Station/Mobile Relay, 800 MHz," 800 MHz Trunked Radio Request for Proposals: Public Safety Projects Office, (Oklahoma City, Oklahoma: Oklahoma City Municipal Facilities Authority, 2000, pp. 165-168.
12. ^ For example, US federal government systems are coordinated and licensed by the National Telecommunications and Information Administration. Business/Industrial Pool licences are coordinated by the Personal Communications Industry Association (PCIA) and licensed by the Federal Communicastions Commission.

The National Telecommunications and Information Administration (NTIA) is an agency of the United States Department of Commerce that serves as the Presidents principal adviser on telecommunications policies pertaining to the United States economic and technological advancement and to regulation of the telecommunications industry. ... The business band is the name used by US scanner hobbyists who listen to Federal Communications Commission licensees using Industrial/Business pool frequencies. ...

External links

• Occupational Safety and Health Admin. Non-Ionizing Radiation Exposure Guidelines.