TETRA and LTE interconnectivity: helping public safety organisations meet the challenges

Paul Ward, our International Sales Director, recently spoke at BAPCO 2019. His theme? How public safety organisations can best meet the challenges of TETRA and LTE interconnectivity.

TETRA, a European standard for a trunked radio system, and LTE, a standard for wireless cellular communication for mobile devices, both have highly useful applications in mission-critical spaces. However, there are some key differences in their functionality, and Paul began by exploring these.

Comparing Data Rates

From a data perspective, TETRA offers low speed data services with narrowband limitations, whilst LTE can support high speed mobile data and new MCDATA standards. TETRA does not support video, whilst LTE does, including real-time high definition video and advanced high-speed data applications TETRA, at 25KHz, is spectrum-efficient, whilst LTE is more spectrum-demanding, though new spectrum discussions are ongoing. TETRA was specifically designed for mission-critical contexts, and therefore offers ideal voice functionality for public safety and emergency services, whilst LTE’s mission-critical functionality is more of a work in progress.

As data-rich applications such as live video and artificial intelligence become more prevalent in public safety contexts, it makes sense to augment purpose-built TETRA technology with newer LTE services. Integration between TETRA and LTE is a powerful strategy because it enables public safety organisations to undertake a more gradual and therefore cost-effective and efficient migration to new technology. New technologies can be used in a complementary way, ensuring familiarity for users and retaining the best features of both the old and the new technologies.

TETRA and LTE interconnectivity in practice

What are the practical options for connecting TETRA to LTE?

Paul went through three core options. Firstly there are proprietary gateways offering interconnection between separate TETRA and LTE networks. These are available from specific vendors but are based on separate networks and separate databases for subscriber management.

Secondly, there is a standards approach currently being developed by 3GPP and TCCA for Inter Working between separate technologies [IWF]. Again, this is a gateway between two separate networks and will be included in the 3PP Standards Release 16, which is expected at the end of this year with systems expected by 2022.

Etelm’s 4GLinked approach however, is based on existing LTE standards and allows our TETRA base stations to connect directly to the Standard LTE core network. This means that there is only one transmission network for both technologies and the subscribers are managed using a single database on the LTE core. The communications between TETRA & 4G subscribers are far more seamless and there is no gateway and no extra latency for inter-system communications, even for group calls.

Using the standard LTE Core for both TETRA & LTE also means that private users have a futureproof solution as they introduce LTE services and makes TETRA services more accessible to Mobile Network Operators as they can simply add TETRA to their existing LTE Core network.

There is a choice for public safety organisations to make between taking services from a commercial operator – which uses existing national infrastructure but means they have less influence over technology – and using private, dedicated networks, which are purpose-designed and give full control over the technology, but require extensive new infrastructure.

Ultimately, whichever route is chosen, organisations must remember that while they can outsource technology, they cannot outsource responsibility. In the public safety context, emergency services agencies are ultimately responsible for a vital service provision, which means that any operators and services chosen must be fully committed to this highly specialist, mission-critical sector.

A new critical communications era

We are entering a new era for emergency services communications, and the mission-critical standards for LTE are evolving quickly. The lowest risk approach for organisations is to undertake a gradual transition of critical communications, and carefully weigh up the different interconnection options available over both the long and the short term.

ETELM is best-placed to support public safety organisations through this transition and guide them through the multitude of options available. For more information, contact us today.