DMR Digital Mobile Radio. Glossary of radio communication terms and abbreviations

Digital Mobile Radio (DMR) is an open standard for digital radio communication, developed for users of professional mobile radio (PMR), created by the European Telecommunications Standards Institute (ETSI), and first ratified in 2005.

In 2005, a Memorandum of Understanding formed a group of manufacturers interested in the new standard, which in 2009 united into an Association to ensure interoperability and the exchange of developments. DMR is primarily aimed at small- and medium-sized radio communication systems, allowing for the migration of subscribers from analog to digital systems.

The standard is designed to operate within the existing 12.5 kHz channel spacing used in licensed frequency bands of land mobile radio worldwide, and to meet future regulatory requirements for channels equivalent to 6.25 kHz. The main goal of the standard is to define affordable digital systems with low complexity.

There are three protocol specifications:

DMR Tier I — license-free solutions in the 446 MHz band, 12.5 kHz channel spacing, FDMA access. Device power up to 0.5 W, no external antennas, no repeaters, no interconnects.

DMR Tier II — for professional handheld, mobile radios and repeaters in licensed VHF and UHF frequency bands. Uses 12.5 kHz channel spacing, access — TDMA.

DMR Tier III — for small- and medium-sized trunked solutions.

The DMR technology is based on TDMA (Time Division Multiple Access — multiple access with time-division channels), which enables two time slots (independent logical channels) on a single frequency carrier with 12.5 kHz channel spacing. The modulation type is 4FSK (four-level frequency shift keying).

From the very beginning, Motorola played an active role in developing the standard. Through continuous research and development in mobile radio communications, Motorola holds a large number of patents. Some of these patents are integral to the DMR standard and are used by all DMR equipment manufacturers.