What is dPMR, dPMR Radio and dPMR446?

21 Sep. 2016   Information

Digital Private Mobile Radio (dPMR) is a Common Air Interface (CAI) for digital mobile communications. dPMR is an open, non-proprietary standard that was developed by ETSI and published under the reference ETSI TS 102 658. A simplified version of the dPMR protocol intended for licence-free applications was also published by ETSI under the reference TS 102 490.
dPMR is a Frequency-Division Multiple Access (FDMA) system offering the lowest cost digital voice and data solutions for PMR. PMR technology that used Time-Division Multiple Access (TDMA) was more spectrum-efficient at wider channel spacings such as 25kHz. The ETSI dPMR standard solves the problem of shortage of radio channels by introducing 6,25kHz FDMA radios with a 4FSK modulation scheme. This newly-developed narrowband 6,25kHz FDMA technology, as used by dPMR, brings greater spectrum efficiency with lower infrastructure cost.
Although the market landscape for two-way radio varies somewhat throughout the world, markets can be roughly divided into three broad categories. In reality the vast majority of systems deployed are DMR. dPMR however does have a niche market with the advocates citing the greater range offered by the true 6.25khz channel spacing and the better spectral efficiency for congested areas. Therefore neither system has "won" the market, with DMR having a large market share, but dPMR looks like it will be around for many years to come.
dPMR has the universal capability to serve them all :
(1) Consumer (and short-range industrial);
(2) Professional/Business-Critical applications;
(3) Public Safety/Mission-Critical applications.

dPMR Functionality
dPMR446
dPMR446 radios are licence-free products for use in the 446.1–446.2 MHz band within Europe. These are fully digital versions of PMR446 radios. dPMR446 radios comply with the ETSI TS 102 490 open standard and are limited to 500 mW RF power with fixed antennas per ECC Decision (05)12. They are ideally suited to recreational and professional users who do not need wide area coverage with base stations and repeaters. dPMR446 equipment is capable of voice, data and voice+data modes of operation. This means that dPMR446 can provide voice calls, text messaging (SMS), status and embedded data such as GPS position etc.
dPMR Mode 1
This is the peer to peer mode of dPMR (without repeaters or infrastructure) but without the limitations of the licence-free counterpart. It can operate all typical licensed PMR frequency bands and without the RF power limits of dPMR446. As well as offering voice and data, dPMR446 Mode 1 also supports combined voice+data so it is possible to embed data into a voice call or automatically append it at the end of a call.
dPMR Mode 2
dPMR Mode 2 operations include repeaters and other infrastructure. This brings extra functionality such as analogue or digital network interfaces which can be IP based. Inclusion of repeaters and base stations means that wide area coverage is possible even more so when multiple repeaters are used. Such multiple repeaters can be managed by dynamic channel selection or they can be part of a co-channel wide area network.
dPMR Mode 3
dPMR Mode 3 can offer multichannel, multisite trunked radio networks. This ensures optimum use of spectrum and optimum density of radio traffic.
Management of the radio network starts from the authentication of radios that wish to connect. Calls are set up by the infrastructure when both parties have responded to the call request ensuring optimum use of the radio resource. Calls may be diverted to other radios, landline numbers or even IP addresses. The infrastructure managing these beacon channels would be capable of placing a call to another radio whether that radio is using the same site or another site within the network.

The Importance of Interoperability
Operators, vendors and manufacturers need to be assured, as early as possible in their development lifecycles, of the interoperability of their products and systems. To facilitate this assurance, ETSI produces test specifications that accompany the core technology standards.
The dPMR Memorandum of Understanding Group has adopted the developed ETSI dPMR conformance and interoperability standards for the purposes of trademarking products. Members of the Group are committed to supporting the use of those standards. This is vital for true competition and interoperability among different manufacturers. As a result, users can have the highest confidence in sourcing equipment from any vendor who has received the Trade Mark from the dPMR Memorandum of Understanding Group.
The Group is active in ensuring an independent validation of interworking between dPMR products from different manufacturers and authorising the use of a specific dPMR logo for compliant equipment. These interoperability and conformance procedures are based on the ETSI dPMR test specification suites TS 102 587 (for Tier 1) and TS102 726 (for Tier 2). The test suites detail the requirements and procedures for any manufacturer developing a dPMR product, and allow them to determine, even during the product’s development phase, whether it is compliant with the standards. With all forms of technology it is vital that products from any manufacturer will interoperate without conflict. 
To ensure that this will be the case, ETSI has also developed and published a range of European standards for compliance and interoperability testing.These standards are the ETSI TS 102 587 series for dPMR446 and the ETSI TS 102 726 series for licensed dPMR Mode1, 2 and 3 products.

(Source: Abstracted from ETSI and Wikipedia)