What is DMR Radio?
16 Jul. 2016 Information
Digital mobile radio
(DMR) is an open digital mobile radio standard defined in the European Telecommunications Standards Institute (ETSI) Standard TS 102 361 parts 1–4 and used in commercial products around the world. DMR, along with P25 phase II and NXDN are the main competitor technologies in achieving 6.25 kHz equivalent bandwidth using the proprietary AMBE+2 vocoder. DMR and P25 II both use two-slot TDMA in a 12.5 kHz channel, while NXDN uses discrete 6.25 kHz channels using frequency division.
DMR was designed with three tiers. DMR tiers I and II (conventional) were first published in 2005, and DMR III (trunked) was published in 2012, with manufacturers producing products within a few years of each publication.
The primary goal of the standard is to specify a digital system with low complexity, low cost and interoperability across brands, so radio communications purchasers are not locked into a proprietary solution. In practice, many brands have not adhered to this open standard and have introduced proprietary features that make their product offerings non-interoperable.
The DMR interface is defined by the following ETSI standards:
TS 102 361-1: Air interface protocol
TS 102 361-2: Voice and generis services and facilities
TS 102 361-3: Data protocol
TS 102 361-4: Trunking protocol
DMR Tier I
DMR Tier I products are for licence-free use in the European 446 MHz band. In the US, the 446 MHz range is primary US Government with the amateur radio service a heavy secondary user. Some DMR radios that make it across the ocean have caused interference issues with licensed amateur operations. Tier 1 equipment is FDMA.
This part of the standard provides for consumer applications and low-power commercial applications, using a maximum of 0.5 watt RF power.
DMR Tier II
DMR Tier II covers licensed conventional radio systems, mobiles and hand portables operating in PMR frequency bands from 66–960 MHz. The ETSI DMR Tier II standard is targeted at those users who need spectral efficiency, advanced voice features and integrated IP data services in licensed bands for high-power communications. ETSI DMR Tier II specifies two slot TDMA in 12.5 kHz channels. A number of manufacturers have DMR Tier II compliant products on the market. HQT has developed private network solutions with integrated hardware and software and provides product series covering DMR Tier-II radios
DMR Tier III
DMR Tier III covers trunking operation in frequency bands 66–960 MHz. The Tier III standard specifies two slot TDMA in 12.5 kHz channels. Tier III supports voice and short messaging handling similar to TETRA with built-in 128 character status messaging and short messaging with up to 288 bits of data in a variety of formats. It also supports packet data service in a variety of formats, including support for IPv4 and IPv6. Tier III compliant products were launched in 2012.
HQT TI OMAP SERIES products are fully self-developed and high-end digital, which are completely compliant with ETSI TS 102 361 protocol. Besides, all HQT TI OMAP SERIES products can be upgraded to DMR Tier III without buying any new devices.
The DMR Association
The DMR Association was first set up in 2005 as the DMR-MOU Association by a group of leading public mobile radio manufacturers to support ETSI during the DMR standardisation process. The DMR Association is open to any organisation or individual interested in using or building DMR products or in supporting the DMR standard in other ways. The Association maintains links with regulators, trade bodies and standards organisations around the world.
As a member of the DMR Association, HQT has been devoting all efforts to developing DMR-related technologies and solutions as well as the technologies of combining the private and public networks.
(Source: the Digital mobile radio part is from Wikipedia and the DMR Association part is from its official website.)