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Glossary
Key terms and abbreviations used in this site are explained below.
A more extensive glossary of EMF specific terms is available from EMF-Portal.
The GSM Association main site has a glossary of mobile communications technology terms.2G 3G A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
2G
2G, the Second Generation of mobile communications systems, is the technology currently used in the operation of mobile phones.
3G
3G, or Third Generation, is the generic term used for the next generation of mobile communications systems. It is sometimes called UMTS in Europe. The new systems will enhance the services available today and offer multimedia and internet access and the ability to view video footage.
A
Antenna; Aerial
A metallic rod or wire for sending and receiving radio waves. There are different designs in operation.Analogue
First mobile phone technology which was phased out in favour of Second Generation digital technology.
B
Base Station
Radio transmitter and receiver used for transmitting and receiving voice and data to and from mobile phones in a particular cell. See here.Basic Restriction
Restrictions on exposure to electromagnetic fields that are based on established health effects and biological considerationsBlood Brain Barrier
The blood-brain barrier (BBB) is a layer between the walls of the blood vessels and brain tissue that is impermeable to certain molecules.Bluetooth
Based on a low-cost, short-range radio link, Bluetooth technology can connect many types of digital devices without a single cable in sight, giving more freedom to roam.
C
Cabin
A structure which protects transmitters and receivers from damage. They can be in the form of large Cabins or smaller cabinets.Carcinogenic
A substance, factor or situation that causes or induces cancer.Case Control Study
Case control studies are epidemiological studies in which patients who already have a certain condition are compared with people who do not. Just because there is a statistical relationship between two conditions does not mean that one condition actually caused the other.Confirmation Study
Follow-up to a prior experiment using methods that may differ from the original study but that are expected to test for the same result.CDMA
Code Division Multiple Access. A technology used for some 2G and 3G mobile communications.Cell
A geographic area of coverage that a Radio Base Stations covers.CW
Continuous Wave. An RF signal without modulation.
D
DNA
Deoxyribonucleic acid, the chemical name for genetic material.Dosimetry
Determination by measurements or calculations of the amount and distribution of radio frequency energy absorbed in a human body exposed to electromagnetic fields.
E
Electromagnetic spectrum
The complete range of stored or propagating electric and magnetic field energies. This includes: power line frequencies, RF, infra-red (IR), visible light, UV, X-rays and gamma rays. A major distinction is made in the spectrum between ionising and non-ionising forms. Read moreElectric Field
A field of force surrounding a charged body or associated with a fluctuating magnetic field, with which charged particles interact.EMC
Electromagnetic compatibility. See here for information on GSMA supported research.EMF, Electromagnetic Fields; Waves
Electromagnetic field. Electromagnetic waves are emitted by many natural and man-made sources and play a very important part in our lives. Electromagnetic waves are used to transmit and receive signals from mobiles phones and their base stations. The type of electromagnetic waves mobile phones use is called radio frequency (RF) waves/fields.EMR
Electromagnetic radiation. Energy stored in alternating electric and magnetic fields that can propagate (travel) through space.Epidemiology
Study of the cause and distribution of diseases in human populations.Exposure
External electromagnetic fields incident to a person. The quantity of an exposure depends on the duration and strengths of the fields.
F
Far field
The area extending from an antenna where the electric fields and the magnetic fields are in phase with each other and are related by the characteristic impedance of free space.Feeder Cable
The co-axial cable which connects an antenna to a base station transmitter or receiver.Field strength
The amplitude of the electric or magnetic fields. Related to the Power density through the impedance of free space.Frequency
Frequency is the number of times per second at which an electromagnetic wave oscillates. It determines the wave’s properties and usage. Frequencies are measured in hertz (Hz). 1 Hz is one oscillation per second, 1 kHz a thousand, 1 MHz is a million and 1GHz is a thousand million. Frequencies between 30 kHz and 300 GHz are widely used for telecommunication, including broadcast radio and television, and comprise the radio frequency band. Mobile telephone systems currently operate in the 800 MHz, 900MHz, 1800MHz, 1900 MHz and 2100 MHz bands.
G
General Public Exposure
All exposure to electromagnetic fields experiences by members of the general public, excluding occupational exposure or exposure during medical treatment.Genotoxicity
Substances that are genotoxic directly or indirectly lead to DNA damage. Genotoxic substances are not necessarily carcinogenic.GPRS
General Packet Radio Service (GPRS) is the world's most ubiquitous wireless data service, available now with almost every GSM network.GSM
GSM (Global System for Mobile communications) is the technology that underpins most of the world's mobile phone networks.
I
In Vitro
These studies use isolated cells or similar preparations and can provide important insights into fundamental mechanisms, however, they cannot generally provide convincing evidence of adverse health consequences due to their isolated and artificial nature.In Vivo
Studies using animals that are more informative for risk assessment than in vitro studies but there remain uncertainties due to biological differences with humans and aspects of RF energy absorption.Intentional Radiators Intentional radiators are designed to radiate EMF and the levels they emit are strictly controlled by EMC and EMF guidelines.
Ionising Radiation Electromagnetic energy with sufficient photon (intrinsic) energy to break chemical bonds. This occurs partway through the UV portion of the electromagnetic spectrum, e.g. X-rays or gamma rays. Ionisation is a process in which an atom or molecule loses or gains electrons, acquiring an electric charge or changing an existing charge.
M
Macrocell
A macrocell provides the largest area of coverage within a mobile network. The antennas for macrocells can be mounted on ground-based masts, rooftops or other existing structures. They must be positioned at a height that is not obstructed by terrain or buildings. Macrocells provide radio coverage over varying distances depending on the frequency used, the number of calls made and the physical terrain. Macrocell base stations have a typical power output in tens of watts.Mast
A ground-based structure that supports antennas at a height where they can satisfactorily send and receive radio waves. A typical mast is 15m high, and of steel lattice or tubular steel construction. New slimmer versions of masts are now available which can be painted to blend in with their surroundings, disguised as trees or used in conjunction with street lighting and CCTV cameras. Masts themselves play no part in the transmission of the radio waves.Microcell
Microcells provide additional coverage and capacity where there are high numbers of users within urban and suburban macrocells. The antennas for microcells are mounted at street level, typically on the external walls of existing structures, lamp-posts and other street furniture. Microcell antennas are smaller than macrocell antennas and when mounted on existing structures can often be disguised as building features. Microcells provide radio coverage over distances, typically between 300m and 1000m and have lower output powers compared to macrocells, usually a few watts.Modulation
Modulation is the addition of information to an RF signal by changing some aspect such as the amplitude, frequency or phase.
N
Near Field
The near field is the region close to an antenna, where the electric and magnetic fields are not related to each other solely by the characteristic impedance of free space.
O
Occupational Exposure
Exposure to electromagnetic fields during work that are experiences by people having appropriate knowledge about EMF.ODC (ornithine decarboxylase)
A chemical marker of cell proliferation or growth.
P
Picocell
A picocell provides more localised coverage than a microcell. These are normally found inside buildings where coverage is poor or where there are a high number of users such as airport terminals, train stations or shopping centres.Power Density
The energy flowing from an antenna through a unit area normal to the direction of propagation in a unit time. This is measured in Watts per square meter.PPS
Pulses per second.
R
Radio Base Station
Radiation
Technical term to describe energy travelling through space, equally applicable to infra-red (IR), light, RF or ultra-violet (UV).
A radio base station is a macrocell, microcell or picocell site and consists of transmitters and receivers in a cabin or cabinet connected to antennas by feeder cable. See more here.
Reference Levels
These are generally derived from relevant basic restrictions using measurement and/or computational techniques. Compliance with the reference level will ensure compliance with the relevant basic restriction. If the measured or calculated value exceeds the reference level, it does not necessarily follow that the basic restriction will be exceeded. However, whenever a reference level is exceeded, it is necessary to test compliance with the relevant basic restriction and to determine whether additional protective measures are necessary.Replication Study
The duplication of a prior experiment using methods very similar to the original study. If the method changes then it may be described as a confirmation study.RF
Radio Frequency. That portion of the electromagnetic spectrum between about 3 kHz and 300 GHz generally used for radiocommunications purposes.
S
SAR
SAR (Specific Absorption Rate) is a measure of the amount of RF power absorbed in any part of the human body due to the use of equipment such as mobile phones or by human exposure close to other transmitting sources. The units are Watts per kilogram (W/kg).Sectored Antenna
Antenna which transmits or receives higher signal levels in a horizontal direction. The base station is split into several sectors (typically 3 or 6) to provide 360 degree coverage.Stub Mast
A roof-mounted mast structure which supports multiple antennas at a height where it can satisfactorily send and receive radio waves. A stub mast is typically 4m – 6m high and of steel lattice construction. Stub masts themselves play no part in the transmission of radio waves.
T
TETRA
TErrestrial Trunked RAdio, typically used by utilities and emergency services.Total Band Exposure Quotient
The sum of the frequency exposure quotients of all the bands at a single location.Transmitter
Electronic equipment that generates radio frequency electromagnetic energy and is connected to an antenna via a feeder cable.
U
Unintentional Radiators
Unintentional radiators are not designed to radiate EMF. Any EMF they do emit are controlled by EMC guidelines
W
Wavelength
Wavelength is the distance in metres between any two ‘similar’ points on a radio wave. This portion of the wave is referred to as one complete cycle. The lower the frequency of a wave the longer the wavelength. For example, the wavelength of ocean waves is the distance between one crest and the next, or one trough and the next.WLAN
Wireless local area network (WLAN) is a low power radio technology which provides special zones for accessing a local area network over a short range, for instance at airports or hotels.WMAN
Wireless metropolitan area network (WMAN) is providing wireless connection for broadband or multimedia users over a medium range, for instance covering small urban areas.
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