definitions

2GConstituting one of the first digital mobile systems, 2G is the second generation of mobile phone technology. The main 2G standards are GSM, IS-95 which is used mainly in the Americas, and PDC which is used exclusively in Japan.

3G3G refers to the third generation of mobile phone standards, mainly represented by the UMTS and CDMA2000 standards. It consists of digital mobile voice and data systems supporting broadband data services, and allows more efficient and faster outputs than the previous generation.

4GFourth generation of mobile phone standards, it marks the advent of « mobile broadband », much superior to 3G. The current 4G standard is Long Term Evolution (LTE) and LTE-Advanced.

amplitudeAmplitude describes the size of a wave, namely the maximum (minimum) value that it can reach.

antennaA radio antenna is a device used to transmit or receive electromagnetic waves.

bluetoothShort-range radio technology making it possible to connect multiple types of wireless device.

cellMaps out a geographic area covered by a base station. The cell size can range from a few tens of metres to tens of kilometres.

electromagnetic fieldOf natural or artificial origin, electromagnetic fields appear when electric charges move. They result from the combination of two waves, one magnetic and the other electric, which propagate at the speed of light. Electromagnetic waves are used in particular to transmit and receive signals from mobile phones and their base stations.

coverageTerritory over which a specific mobile network is available.

SARThe index of specific absorption rate (SAR) which quantifies the level of exposure of the human body to radio waves locally or globally. For a mobile phone, it quantifies the maximum exposure level when the unit is placed against the ear and working at maximum power. It is measured in W/kg.

deploymentAction to extend a wireless network.

dosimetryDetermination, by calculation or measurement, of exposure to radio waves.

epidemiologyStudy of the frequency, geographical distribution and conditions of appearance of disease.

exposureTerm used to describe the total quantity of energy of an electromagnetic field received in a location. See also SAR.

femtocellA femtocell is a low-power access point to mobile networks intended to provide limited radio coverage and often dedicated to residential or business use.

frequencyNumber of identical waves (oscillations or vibrations) in a given unit of time. The unit of frequency is the hertz.

GSMThe second-generation standard (2G) the best known and most widespread in the world for mobile phone systems. GSM stands for “Global System for Mobile communications”.

handoverThe transfer of information (communication, localisation, etc.) of a mobile from one cell to another.

hertzThe frequency unit used internationally, equal to one period per second. Its symbol is Hz.

wavelengthThe wavelength is the distance travelled by a wave in the time between two successive peaks.

LTELTE or “Long Term Evolution” is a fourth-generation standard (4G) defined by the 3rd Generation Partnership Project consortium (3GPP).

radio waveA radio wave is an electromagnetic wave whose frequency is conventionally between 9 kHz and 300 GHz.

WHOThe World Health Organization is an agency of the United Nations (UN) specialised in public health issues.

radio frequencySee radio wave.

ionising radiationIonizing radiation is a wave that is sufficiently energetic to break atoms or molecules (ionisation): UV, X rays, gamma rays.

non-ionising radiationNon-ionising radiation does not carry sufficient electromagnetic energy to cause ionisation. Such radiation includes microwaves, radio waves, infrared waves or visible light.

electromagnetic spectrumRefers to the range of wavelengths for electromagnetic waves – from the longest to the shortest. The lowest part of the spectrum with significant wave lengths is non-ionising, while the upper part of the spectrum with very short wave lengths is ionising (X-rays, gamma rays).

base stationA radio transmitter and receiver equipments with antenna used to transmit and receive voice and data to and from mobile phones in a given cell.An equivalent term is relay antenna.

HandoffSee « handover ».

UMTSUMTS or “Universal Mobile Telecommunications System” is one of the standards corresponding to 3rd generation mobile phones.

limit valueLevel of maximum permitted exposure to radio waves expressed in W/kg.

Wi-FiWireless technology to connect several devices to each other through an access point to internet.