Codan Radio P25 Training Guide - Manual (Page 20)

TRAINING GUIDE | P25 RADIO SYSTEMS
Chapter 1: Introduction To P25 Page 12
OTHER DIGITAL STANDARDS
Although P25 is the focus of this document, it is important to understand that there are many different
digital radio standards in use around the world. P25 has primarily been adopted for use in North
America, while another leading digital standard, TETRA (Terrestrial Trunked Radio) has primarily been
adopted for use in Europe.
While P25 and TETRA appear to be the two leading digital Land Mobile Radio standards in the
world today, there are other digital, spectrally-effi cient radio systems that have been submitted to the
International Telecommunication Union’s Radiocommunication Sector’s (ITU-R) Study Group 8 and its
Working Party 8A.
ITU-R is charged with determining the technical characteristics and operational procedures for a growing
range of wireless services. The Radiocommunication Sector also plays a vital role in the management
of the radio-frequency spectrum. Study Group 8 and its Working Party 8A is responsible for studies
related to the land mobile service, excluding cellular, and to the amateur and amateur-satellite services.
Digital radio systems can operate using different channel access methods such as FDMA (Frequency
Division Multiple Access), TDMA (Time Division Multiple Access), or other methods (FHMA - Frequency
Hopping Multiple Access).
Project 25, Tetrapol, and EDACS® (Enhanced Digital Access Communications System) Aegis™ are
three different FDMA systems. TETRA, DIMRS (Digital Integrated Mobile Radio System), and IDRA
(Integrated Digital Radio) are three different TDMA systems.
Tetrapol
France submitted Tetrapol to ITU-R Working Party 8A. It uses a constant-envelope modulation technique
that fi ts within a 10 kHz channel mask. Systems are in use in a number of countries in Europe and
around the world. EADS is the principal manufacturer of this equipment.
EDACS® Aegis™
L.M. Ericsson AB (with support from the Swedish Administration) submitted EDACS® Aegis™ to ITU-R
Working Party 8A. It uses a constant-envelope modulation technique and has four different selectable
levels of deviation and fi ltering that can result in the signal fi tting within 25 kHz and 12.5 kHz channel
masks. Systems are in use in a number of countries around the world. M/A-COM, Inc. is the principal
manufacturer of this equipment.