A cell site is a site where antennas and electronic communications equipment are placed to create a cell in a cellular network for the use of mobile phones. A cell site is comprised of an antenna tower (or antennas mounted on an elevated structure, such as a building), transmitter/receivers transceivers, digital signal processors, control electronics, a GPS receiver for timing, regular and backup electrical power sources, and sheltering.

Cell sites are connected via T1s (leased line or microwave) and T3s (leased line, microwave, or optical fiber) to a base station controller (BSC) at the mobile telephone switching office (MTSO). The base station controller is connected to a telephone switch, which is connected to the public switched telephone network (PSTN).

Synonyms for "cell site" include base station, cell tower (although many cell site antennas are not mounted on towers), and mobile phone mast (British English).

A controversial issue is whether there is a correlation between radio transmission and the risk of cancer. Safety regulations exist to protect the public from extensive exposure to radio waves emitted by cell sites.

Cell Site Range

The working range of a cell site - the range within which mobile devices can connect to it reliably is not a fixed figure. It will depend on a number of factors, including

• The type of signal in use (i.e. the underlying technology), similarly to the fact that AM radio waves reach further than FM radio waves.
• The transmitter's rated power.
• The transmitter's height.
• It may also be limited by local geographical or regulatory factors and weather conditions.

Generally, in areas where there are enough cell sites to cover a wide area, the range of each one will be set to:

• Ensure there is enough overlap for "handover" to/from other sites (moving the signal for a mobile device from one cell site to another, for those technologies that can handle it - e.g. making a GSM phone call while in a car or train).
• Ensure that the overlap area is not too large, to minimise interference problems with other sites.

The maximum range of a site (where it is not limited by interference with other sites nearby) depends on the same circumstances. Some technologies, such as GSM, have a fixed maximum range of 35 km, which is imposed by technical limitations. CDMA and iDEN have no built-in limit, but the real limiting factor is really the ability for a low-powered personal cellphone to transmit back to the site. As a rough guide, based on a tall site and flat terrain, it is possible to get between 50 and 70 kilometers. When the terrain is hilly, the maximum distance can vary from as little as 5 to 10 km to about 40 km. ^*

See also

• Base station
• Base Transceiver Station
• Mobile phone
• Cellular repeater
• Portable phone
• Signal strength
• Mobile phone radiation and health

External link

• FCC: Information On Human Exposure To Radiofrequency Fields From Cellular and PCS Radio Transmitters

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