DMR vs dPMR | difference between DMR and dPMR technologies
Introduction : DMR (Digital Mobile Radio) and dPMR (digital Private Mobile Radio) are two different digital radio communication protocols. They are similar in their usage of TDMA for spectrum efficiency and support for encryption and data services. They are distinct standards with their own specific implementations.
What is DMR ?
The DMR stands for "Digital Mobile Radio". It is developed and supported by ETSI and DMR association. It is designed for two-way radio applications and operates in VHF/UHF frequency bands. It utilizes Time Division Multiple Access (TDMA) technology to allow two channels to share same radio frequency band. This doubles the number of users that can be accommodated and increases spectrum efficiency.
Refer DMR tutorial which describes DMR system basics. It also covers DMR Radio features, network architecture, air interface, channel types, advantages of DMR and so on.
What is dPMR ?
The full form of dPMR is "digital Private Mobile Radio". It is digital radio communication protocol which is used as two-way radio communication for commercial and professional. It is an open standard developed by ETSI to provide efficient and secure voice and data communication for various applications.
The key features of dPMR are as follows.
• dPMR uses digital modulation techniques to provide clear audio quality.
• It allows more efficient use of radio spectrum by accommodating more channels within same frequency band.
• It supports encryption which ensures secure communication for sensitive information and prevents any unauthorized access.
• It supports various data services such as text messaging, status updates, data transmission etc.
• It is primarily used in Europe and some other regions.
• dPMR is designed to be backward compatible with existing analog PMR systems which makes migration easier.
Difference between DMR and dPMR
Let us compare DMR vs dPMR and understand the similarities and difference between DMR and dPMR protocols based on their benefits or advantages and respective features in the table format below.
| Specifications | DMR | dPMR |
|---|---|---|
| Full Form | Digital Mobile Radio | Digital Private Mobile Radio |
| Bandwidth | Typically 12.5 KHz per channel (DMR Tier I/II), 6.25 KHz (DMR Tier III) | Typically 6.25 KHz per channel, other licensed dPMR may use wider BWs |
| Operating frequency bands | 446.00625 MHz to 446.19375 MHz (Europe) for DMR Tier-I, VHF (136-174 MHz) and UHF (403-470 MHz) for DMR Tier-II/III | 446.00625 MHz to 446.19375 MHz (Europe) and other licensed bands such as VHF (136 to 174 MHz) and UHF (403 to 470 MHz) |
| Access scheme for resource allocation | Uses TDMA in which each channel is divided into two time slots, typically referred to as Time Slot 1 and Time Slot 2 | Uses TDMA in which each channel is divided into two time slots, typically referred to as Time Slot 1 and Time Slot 2 |
| Data rate | About 9.6 Kbps (Voice and data) | About 4.8 kbps (Voice and data) |
| Encryption | Supports optional encryption | Supports basic encryption |
| Modes | DMR is categorized into three tiers Tier-I, Tier-II and Tier-III based on features, Refer DMR Tier-1 to 3➤. | There two modes in dPMR viz. tier 2/mode 2 and tier 2/mode 3 |
| Migration from analog FM | The migration from analog FM system is simple and requires 1 repeater, 1 antenna and 1 duplexer as it uses same frequency channels with same bandwidth | Migration from analog system to dPMR needs two repeater, one for each of the 6.25 KHz channels, extra RF combiners to combine these two channels in order to utilize single Base Station transceiver or single antenna. |
| Examples | Motorola MOTOTRBO | Kenwood NX-300G |
| ETSI standard references | TS 102 361-1 to 4 documents, TIA-102 and TIA-102.CAAA (For DMR requirements in USA) | TS 102 490 (Primary Standard), TS 102 658 (dPMR radio equipment's interference cancellation system (ICS) |
Conclusion: As digital radio protocols, both dPMR and DMR benefit from features like reduction in background noise, immunity against analog signal distortions and consistent voice quality over the range of the radio signal. After understanding comparison between DMR and dPMR technologies, the choice between DMR vs dPMR will depend on factors such as regional availability, specific application requirements and compatibility with existing radio systems or technologies.
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