Digital Mobile Radio (DMR) is a digital radio standard developed by the European Telecommunications Standards Institute (ETSI) specifically for professional mobile radio users.
DMR devices are categorized into three tiers
1. Tier 1 devices are used for cost-effective digital walkie-talkie applications.
2. Tier 2 devices are prepared for professional modes like peer-to-peer and relay modes.
3. Tier 3 devices are for professional cluster communication modes, where Tier 1 and Tier 2 devices use confirmed and unconfirmed data transmission services, as well as short data transmission services.
What are the characteristics of DMR digital radios?
1. Excellent Audio Performance
DMR’s digital technology better suppresses noise, particularly at the coverage edges, providing superior voice quality compared to analog technology. This advantage is due to the application of narrowband codecs and digital error correction techniques.
Digital processing filters noise and reconstructs signals from degraded transmissions, resulting in clearer conversations. DMR improves the effective coverage range of wireless communication, allowing users to handle changing work conditions seamlessly.
2. Doubled User Capacity
A key advantage of DMR is that a single 12.5kHz channel can support two synchronous or separate conversations. Time Division Multiple Access (TDMA) in DMR retains the 12.5kHz bandwidth and divides it into two alternating time slots. Each time slot operates as an independent communication channel with an equivalent bandwidth of 6.25kHz. This compatibility with existing authorized PMR frequencies eliminates the need for reconfiguration or additional frequency purchases, effectively doubling the 12.5kHz bandwidth capacity.
3. Reduced Infrastructure Costs
Another advantage of DMR’s TDMA technology is that it only requires one repeater, one antenna, and one duplexer for two channels. Compared to Frequency Division Multiple Access (FDMA), the dual-slot TDMA provides twice the bandwidth efficiency at 6.25kHz, while minimizing investments in repeaters and combining equipment.
4. Extended Battery Life
Mobile devices have long faced the issue of short battery life. However, the emergence of dual-slot TDMA addresses this problem. Each conversation uses only one time slot, utilizing half the transmitter’s capacity. As slots alternate, the transmitter spends half its time in idle mode.
5. Enhanced Privacy
While analog channels are susceptible to eavesdropping, DMR’s advanced digital technology ensures voice signals cannot be intercept if signals or IDs (with up to 16,776,415 possibilities) do not match, maximizing communication privacy.
6. Gradual Compatibility with Existing Analog Systems
DMR supports operation in analog or digital mode. Therefore, compatibility concerns with your current analog system are alleviated, allowing you to fully enjoy the benefits it offers.