Cellular Base Stations – Cellular Sites

A cellular communication base station is an apparatus for transmitting and receiving electromagnetic waves in the radiofrequency (RF) range and it is the site through which cellular devices communicate with communication systems deployed throughout the world. The antennas of a cellular base station are the source of radiofrequency radiation that is transmitted through the spatial volume of the cell that it serves.

Although the term 'base station' usually refers to cellular communication, base stations serve all types of wireless communication.  A base station generally constitutes a link in a network of additional base stations, as part of a communication system covering a wide geographic area, providing cellular and other communication services.

• Components of a cellular base station
• The base station and the cellular communications network
• Designated functions of a cellular base station
• Exposure to radiation from cellular base stations

Components of a cellular base station

A base station (cellular site) comprises the following instruments and technologies:

• Antennas: serve for the transmission and reception of signals.  In order to supply good transmission and reception conditions, the antennas are placed high off the ground – on top of a tower, on roofs of buildings or close to them.  The antennas may be of different types and sizes, e.g. tilting antenna, wireless access device, mast antenna. The antennas may be directional, adaptive (power adapted to distance-direction conditions) or of other kinds, in accordance with the communication generation and its technologies.
• Communications room: the location for storage of electronic equipment, e.g. communication apparatus, receivers, transmitters and amplifiers.
• Computer system: contains the monitors that control transmitters and receivers.  The computer system relays links to the communication switches (line or wireless) and contains the interface with it, according to the relevant communication technology.  The switch systems enable the control and monitoring of the passage of a large number of communications through the network.
• Integration of the base station in the global network: the integration of a single cellular site (base station) into the general cellular network may be performed by regular line telephony, by optic fibers, or by microwave/satellite communication intended for rapid communication.
• Electricity supply systems: such as power systems and backup systems in the case of power failures.

[Back]

Base stations and cellular communication networks

The infrastructure for the network that provides wireless cellular communication for subscribers usually comprises four main components, which are coordinated and interrelated.

• Public Switched Telephone Network (PSTN) – the infrastructure of the line network provides the interface between the cellular communication systems and the line communication systems.
• Mobile Station Center (MSC) supports about 100,000 subscribers and about 5,000 connections conducted simultaneously.  The station center performs the functions of communication control and finance management.
• Cellular site also known as base station
  To read about exposure to radiation from cellular base stations
• End user devices – such as mobile phones, tablets, laptops and portable terminals. 

[Back]

Designated functions of cellular base stations 

Base stations may perform one or more of the following functions:

• Cellular communication: this is the main function of the base station as part of the cellular communication network.
• Wireless access point: a base station may serve as a point enabling access to computer communication networks (such as the Internet and wireless networks, through modems), and to personal digital accessories (PDAs) such as palm computers, tablets and mobile phones, and smart meters.
• Charting and navigation: a base station may complement a satellite navigation system: the geographic location of base stations is known precisely, and they constantly monitor the difference in distance between this location and the data on locations received through satellite navigation systems. The base stations send the information on the varying distances to the navigation system, and the corrections received through its instruments enable the navigation programs to find the location more precisely.
• Mediation between communication devices: base stations may serve as mediators in autonomic wireless communication systems (such as two-way radios or handheld transceivers). If one transmitter in this system moves away from the reception range of the communication system, the communication may be enabled through one or more base stations.

[Back]