DMR:A better digital platform for large and high capacity networks.

By Monique Princen

Since its inception in 2005, conventional DMR (Digital Mobile Radio) has become the world’s most widely-deployed digital PMR radio technology. Small-to-medium sized businesses around the planet have enthusiastically adopted and exploited the significant capabilities offered by the DMR standard.

The release by Tait in 2012 of a “Tier 3” trunked DMR solution will see the next step in the evolution of digital radio communications for large and multi-use networks. Trunked DMR Tier 3 is simply the most cost-effective successor to MPT and other analog trunked networks.

DMR Tier 3 offers easy migration from MPT 1327, preserving the familiar MPT user interface while adding the significant operational benefits of DMR’s data capabilities.

What does DMR Tier 3 offer the professional mobile radio user?

Greater spectral efficiency

The DMR standard already offers effective 6.25 KHz channel spacing. By adding Tier 3 trunking capabilities to DMR, the available spectrum will be used even more efficiently. Trunking technology dynamically assigns channels to users to ensure no channel will ever be disused as long as there is an active requirement for channels.

Increased privacy and security of conversations

With DMR trunked networks only designated group participants can listen into any communication. Eavesdropping on a trunked DMR conversation is a significantly more difficult technical challenge than eavesdropping on conventional networks. This is because trunking technology dynamically assigns channels to new conversations. It is therefore never known in advance of any communication what channel the group will be allocated. Such a task would require specialised scanners.

Improved reliability

Because trunking technology dynamically allocates the available channels in real time to the users requesting communication, there is no permanent allocation of channels to individuals or groups. This dynamic assignment ensures that no user is ever left without access to communications because one channel has failed or become unavailable.

Improved security

Because the DMR network will only grant access to terminals that pass an authentication test the risk of unauthorised access to the network is dramatically reduced.

Cost efficient

Because a trunked DMR network dynamically assigns channels to users in real time managing users on a trunked network is a great deal easier and simpler than on a conventional network.

Additional DMR advantages include:

• Significantly clearer voice communications
• More advanced control features
• Longer battery life
• Combined voice and data networks

Rolling out Trunked DMR Tier 3 in a real world utility situation

To paint a picture of the adoption of Trunked DMR into a typical utility environment, let’s imagine a large utility that has been operating an analog radio network for voice communications...

The network is now due for replacement as it no longer meets the utility’s needs.

To replace the radio network, the utility first undertook detailed analysis of how a new communication system would improve the efficiency and safety of their workforce. They discovered that a new digital radio system could provide truly innovative operating applications, significant operational efficiencies and advantages by supporting location awareness and job dispatch alongside their emergency voice communications.

During an outage, a communication system with these capabilities would allow the utility to direct the closest crew to the outage location and resolve the problem rapidly, with minimal travel time. Sending an IP data message to the DMR mobile radios with detailed job information will mean the crew will know the exact nature, location and other critical information required to resolve the outage.

Workforce safety will also be improved. In an emergency, the utility will know the exact location of the affected crew and will be able to immediately send the closest support team to assist.

The utility has calculated that the new system will require additional channels to support data. Part of this additional capacity requirement will already be met by DMR’s 2-slot TDMA operation, but an increase in the number of channels is still needed for maximum benefits.

Replacing the utility’s legacy conventional network with a digital trunked network will make it easier to manage the radio network, dynamically configuring channels for voice or data depending on need. Emergency voice will always receive priority to ensure the safety of the workforce, thanks to DMR reverse signalling.

The Tait approach to network migration offers the utility a staged migration path that guarantees service throughout the change process. DMR Tier 3 also offers this utility maximum re-use of their existing equipment to deliver the best possible return on their investment, actively contributing to the efficiency of their organization.

Looking to the future, the new DMR Tier 3 system will support the utility’s need for capacity expansion, for security features including encryption and authentication when these become necessary and it will help to ensure the utility’s critical infrastructure remains protected.

While DMR Tier 2 has proven its capabilities in the past few years, for wide area and multi-use networks DMR Tier 3 significantly raises the bar, providing maximum efficiency, security and future-proofing.

source: TAIT