Glossary

Amplitude Modulation

A way of using variation in the amplitude (height) of a wave in order to carry meaningful information.

Analogue radio system

A radio system that transmits information using continuously variable signals. Analogue radio systems, because they are less efficient, are being phased out in favour of digital radio systems.

Base station

The mast and radio part of the network infrastructure. A single base station usually contains several radio transmitters, receivers, control sections and power supplies.

Conventional/traditional procurement

A procurement for a contract in which the public sector customer, using Government finance, pays the contractor as the works progress. Such projects are fully paid for on completion. Operation and maintenance of the resulting assets are dealt with in separate contracts.

Digital radio system

In relation to Airwave, a radio system that transmits information in time-wise discontinuous signals. These systems encode information into a binary "1" or "0" code and can transmit more information over a given radio frequency band width than analogue radio systems.

Encryption

Conversion of plain language into a coded signal. The greater the sophistication of the encryption, the greater the security so keeping communication private. Only other users or devices that have the key to the encryption can access the information.

Financial models

Spreadsheets designed to show the financial outcome of a particular set of estimated costs, revenues and fixed and capital charges for delivering a service over time.

Group calls and talkgroups

A group call is a call to a pre-set group of terminal users called a talkgroup (usually including a radio dispatcher) and works in a similar way to a traditional channel. When using a selected talkgroup everyone in that talkgroup receives the communication.

GSM

Global System for Mobile Communications -The digital cellular telephone system employed by most private mobile phones.

Non-ionising radiation

In general, light, microwaves and radio frequencies.

Output specification

In relation to Airwave, the specified aspect of PITO's service requirements and performance specification, for which PITO set minimum quality standards to be met by bids.

PITO

Police Information and Technology Organisation.

Police authority

A body that oversees target setting and budgets for its local police force and which monitors delivery of service and conducts reviews of Best Value. It is the means of achieving local accountability for its police force.

Police force

Headed by a Chief Police Officer, each police force is responsible for the maintenance of public peace and order, enforcement of laws, and prevention and detection of crime within the force's boundaries.

Private Finance Initiative (PFI)

A policy introduced by the Government in 1992 to harness private sector management and expertise in the delivery of public services.

Public sector comparator

An estimate of what the project would cost if traditional procurement methods were used. This is used to determine whether private finance offers better value for money than traditional procurement.

Repeater

On the Airwave service this is a device which receives the signal and retransmits it so it can be picked up by nearby units.

Roaming

Ability of police officers to move around the country and still be in radio contact with their control rooms and with other officers in their forces.

Should-cost model

In the case of the Airwave procurement, PITO's model that calculated the approximate cost to O2 of providing the assets and services needed to deliver Airwave. Input quantities of components and labour were provided by O2 from its design. Input costs were repeatedly renewed by PITO.

Terminals

A generic term for any device that can be used to access the Airwave service. These include handheld and vehicle-mounted radios as well as other devices such as Mobile Data Terminals.

TETRA

Terrestrial Trunked Radio - A European open standard for digital trunked radio systems, designed primarily for public safety organisations.