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What is the DMR Digital Mobile Radio Standard?
Time：
2020-12-11 14:30
Source：
DMR(Digital Mobile Radio) digital trunking communication standard is an open standard designed and formulated by ETSI(European Communication Standards Association) to meet the needs of middle and low end professional and business users in Europe for mobile communication.
The digital mobile wireless system standard was introduced in April 2005. The latest version was released in December 2007.
The DMR Association is an alliance of major manufacturers of DMR products, including Motorola, Hytera, Selex, Tait, and others. Key members of the Alliance: Aeroflex, CML, Democom, Funkwerk Koelleda, Fylde, Hytera, ICOM, KENWOOD, MOTOROLA, Radio Activity, Team Simoco, SELEX, Tait, Vertex, Professioneller Mobilfunk.
DMR standards are drafted for the middle and low end professional and business needs, applicable to utilities, schools, hospitals, hotels, property and other industries.
DMR standard uses TDMA(dual slot) multiple access mode, 12.5KHz channel interval, 4FSK modulation mode, data transmission rate of 9.6Kb/s. This standard is divided into three phases: the first phase is the digital standard of free frequency band, the second phase is the digital standard, and the third phase is the cluster phase.
This standard is designed to operate within the 12.5KHz channel intervals used in the existing global licensed terrestrial mobile frequency bands and to meet future regulatory requirements for channel equalization at 6.25kHz. The main goal is to specify a low complexity, affordable number system. DMR provide voice, data, and other ancillary services. Today, products designed to its specifications are sold around the world.
The DMR protocol covers three operation modes: unauthorized (Layer 1), authorized general (Layer 2) and authorized cluster (Layer 3). The commercial application focuses on authorized general (Layer 2) and authorized cluster (Layer 3).
DMR has the advantages of efficient utilization of spectrum resources, regional networking mode and compatibility with conventional simulation. Its service features are rich, scalable, and backward compatible. At the same time, the system and terminal costs are low, the network construction speed is fast, and the overall operation and maintenance cost is low.
Other key technical features of the DMR standard include:
Dual time slot Time division Multiple access (TDMA) operation
4 stage FSK modulation
State-of-the-art forward error correction
There are three levels of DMR standards.
DMR Layer I: unauthorized
DMR Layer I products are available for license-free use in the 446MHz band.
Tier I provides consumer and low-power commercial applications with a maximum RF power of 0.5W. With limited channels and no use of Repeaters, telephone interconnections, and fixed/integrated antennas, Layer I DMR devices are best suited for personal, entertainment, small retail, and other environments that do not require wide area coverage or advanced features.
DMR Layer II: DMR routine
Tier II includes licensed conventional radio systems, cell phones and portable devices operating in the 66-960mhz PMR band. ETSI's DMR Tier II standard is targeted at users who require spectrum efficiency, advanced voice capabilities and integrated IP data services for high power communication over licensed frequency bands. The DMR Layer II of ETSI specifies the operation of a two-slot TDMA in a 12.5KHz channel.
DMR Layer III: DMR cluster
DMR Layer III products can be clustered in the 66-960mhz band. The Tier III standard specifies dual-slot TDMA operating in 12.5KHz channels. Layer III supports voice and short message processing similar to the MPT-1327, with built-in 128-character status messages and short messages in various formats up to 288 digits. It also supports packet data services in multiple formats, including IPv4 and IPv6.
The DMR Association is a global organization that promotes DMR as the most widely supported 21st century digital radio standard in business. Through interoperability testing, certification, education and awareness efforts, the DMR Institute is committed to ensuring that today's commercial buyers of digital radio technology can extract value from the open and multi-vendor value chains through competition and choice.
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