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Spectrum Management: Into the 21st Century
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Italics indicate terms defined in the glossary.
Allocation
a) The process of identifying specific frequency ranges for specific
applications; or
b) a frequency band entered in a table of frequency allocations for use by one or more terrestrial or space radiocommunications services or the radioastronomy service under specified conditions.
Assignment
Authorisation given by a licensing authority for a radio station to use a
specific radio frequency or channel under specified conditions.
Attenuation
Reduction in strength of a radio signal as a result of atmospheric absorption,
obstruction by buildings etc.
Availability (of a fixed link)
A measure of the probability that communication will not be prevented by
propagation conditions or interference. There are three grades of
availability: 99.9%, 99.99% and 99.999%.
Bandwidth
The range of frequencies occupied by a radio signal or the range of frequencies
over which a radio receiver operates.
Cellular radio
A mobile radio system, usually one providing public telephone services, in which
the service area is divided into a number of smaller areas (‘cells’), the base
stations of each cell generally being interconnected to provide continuity of
communications from cell to cell. Civil radio use
Use of radio spectrum by non-military commercial and government users, including
broadcasting, telecommunications, police, fire, ambulance, coastguard etc.
Common base station (cbs)
a) A single channel base station for pbr shared by users (also known as a community
repeater); or
b) a pbr installation giving wide area coverage under the control of one or more operators offering mobile communications on a commercial basis to a number of independent (usually business) users.
Digital
A technique or signal in which the information (voice, data etc) is transformed into a
stream of binary code for transmission, as opposed to analogue in which the radio output
signal varies continuously in line with the input. Digital techniques can offer increased
quality, security and spectrum efficiency compared to the analogue alternative.
Earth station
Centre for communicating by radio with a space satellite.
Electronic news gathering
Television coverage of news events etc by means of television cameras (as opposed to film
cameras) generally using equipment sufficiently lightweight to be carried by one or two
operators, the signal being either recorded or transmitted via a radio link to a base
station.
Federal Communications Commission (FCC)
An independent federal agency in the USA reporting to Congress and responsible for
managing all frequencies assigned to users other than federal administrations.
Fixed link
A communications link between two fixed points. Such links may be uni-directional (eg
carrying television programme material to a transmitter) or bi-directional (eg carrying
telephone traffic), and may be point to point or point to multipoint.
Frequency
Radio signals are electromagnetic waves that travel at the speed of light and vary
periodically in time and over distance. Frequency, measured in Hertz
denotes the rate at which the signal varies in time. Radio frequencies are
conventionally taken to range from 3 kHz to 3,000 GHz. Wavelength is the
periodicity in space. The two measures are related by the formula:
(Frequency)x(Wavelength) = (Speed of light).
GigaHertz (GHz)
A frequency of one thousand million Hertz.
Hertz (Hz)
Measure of frequency named after a German physicist. 1 Hz corresponds to
a frequency of one cycle per second.
Interference
The effect of unwanted signals on reception of wanted signals in a radio system,
resulting in degradation of performance, misinterpretation or loss of information.
International Telecommunication Union (ITU)
The United Nations agency that coordinates and manages radio use worldwide
through the international Radio Regulations that it promulgates. These have the status of
an international treaty and are binding on member states.
KiloHertz (kHz)
A frequency of 1,000 Hertz.
MegaHertz (MHz)
A frequency of one million Hertz.
Microwave frequencies
Radio frequencies at the higher end of the radio spectrum, generally above 1 GHz
(1,000 MHz).
Military use
Use of spectrum by the armed forces, including the Ministry of Defence, for internal
communications.
Millimetre wavelengths
Frequencies towards the upper end of the radio spectrum (above 30 GHz) with a
wavelength on a scale of millimetres.
Multipoint video distribution system (MVDS)
A system that uses microwaves to distribute television programmes either to the
general public or to cable television systems over a relatively small area.
Opportunity cost
The return from the use of an asset or resource in the next best alternative that is
foregone by virtue of its actual use.
Optical fibre
Very fine (hairsbreadth) strands of pure glass that carry light signals and can be used
for very high capacity telecommunications links.
Paging
A service in which short messages are sent to a portable receiver, which may store or
display them in alphanumeric form.
Personal communications network (PCN)
In the UK, the term is used to describe cellular mobile telephone networks
licensed at higher frequencies (around 1.8 GHz).
Point to multipoint fixed link
Fixed link having at one end a multi-directional antenna for communication with a
number of users over a relatively small area. Used, for example, for MVDS and radio
fixed access for telecommunications.
Point to point fixed link
Fixed link, generally using highly directional antennas at each end, for
communication between two fixed points.
Private business radio (pbr) - previously known as private
mobile radio (pmr)
A private radio service installed and operated by business or public sector organisations
to provide mobile communications for their own workforces. A base station is installed by
the organisation on a suitable site to provide local coverage and used to communicate with
mobile units.
Propagation
The transmission of radio waves. Propagation characteristics depend on frequency
and are affected by the environmental conditions, such as terrain and atmospheric
conditions, encountered on the path.
Public access mobile radio (pamr)
Regional or national systems with wide area coverage and similar functionality to pbr
but provided on a commercial basis by a third party and supporting a number of users,
generally businesses.
Radio fixed access Use of point to multipoint fixed links to connect subscribers to a telecommunications network.
Radioastronomy
The study of radio signals from space.
Service provider
a) Public or private sector organisation providing radiocommunication services; or
b) the intermediary between a network operator and subscribers.
Services ancillary to broadcasting and programme making Radio services used in the production of programmes for broadcasting or other entertainment purposes to carry programme material (eg radio microphones) or control channels.
Spectrum management organisation (SMO)
An organisation that undertakes the administrative and technical management of part of the
radio spectrum, usually limited to the identification of suitable assignments,
record keeping, calculation of interference risks etc and also the distribution
of licences.
Trunked radio
A system in which users share or pool a number of radio channels. Frequencies are
distributed by the system according to demand and traffic levels. Trunking can enhance
spectrum efficiency in some circumstances.
Wavelength
The periodicity of a radio wave in space. Measured in units of distance and
related to frequency. Radio wavelengths range from millimetres to kilometres.
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