Over recent years, much of the discussion among the mission-critical comms community has revolved around an anticipated, imminent, embrace of broadband technology.
There are many reasons for this, not least the number of high-profile national projects – particularly in the public safety sector – now focused on rolling out LTE. As is well known, this included the UK, South Korea and the US in the early going, followed in turn by France, Finland and so on.
While that is, of course, hugely exciting, the other side of the discussion has inevitably focused on what broadband might be replacing, particularly when it comes to mission-critical voice.
And as longtime readers of CCT will know, in Europe (and elsewhere around the world) this invariably means TETRA.
Referring back to some of the original programmes mentioned above, this is probably no surprise given that a key driver for those such as the UK was – and still is – the desire to turn off the TETRA-based Airwave network. This continues to be a massively high-profile project after all, not just for what it has set out to achieve but also the difficulties that have been encountered in achieving it.
Having said all that, however, over a decade after the original ‘broadband for public safety’ discussions began, it is apparent that an immediate swop from TETRA to LTE might be more difficult than first envisioned. We shall explore this more as the piece progresses.
With that in mind, there are several countries taking a more hybrid-based approach to MCX roll-out. Furthermore, there are also countries that have not fully completed their TETRA roll-out yet.
Taking all that into account, the question then becomes how does the sector, and indeed public safety organisations, proceed in the intervening years prior to MCX being fully adopted across the globe? More to the point, how does the TETRA standard itself need to evolve in the coming decades, during which it will likely remain the go-to technology for mission-critical voice?
These are the questions which this article sets out to answer.
The need to evolve
Francesco Pasquali is a TCCA Board member, as well as chair of the association’s TETRA Industry Group. Discussing the necessary evolution of the technology, he believes that this will take place across two broad areas – the security piece, and ‘hybridisation’ to enable simultaneous working
with broadband.
Beginning with security in the first instance, he says: “In my opinion, TETRA will remain the optimal [voice] technology solution for many years. In the meantime, however, the cyber threat is growing.
“For instance, freely available computational power is increasing, making it easier to crack encryption systems through brute force attacks. It’s clear, therefore, that TETRA needed to evolve and be upgraded in this regard.”
Illustrating this, he highlights the recent introduction of a new set of TETRA security algorithms, developed in conjunction with ETSI. These, he says, have been designed to resist even brute force attacks, as well as taking into account any future threat
potential from quantum computing. TCCA is already working on the TETRA interoperability certification needed for this.
Readers will also recall that ETSI recently made the decision to publish the TETRA security algorithms in the public domain. The rationale for this was to demonstrate their quality as well as make them available for peer review, following the Midnight Blue ‘TETRA:Burst’ findings published in the summer of 2023.
Discussing this, a statement released by ETSI at the time said: “Keeping cryptographic algorithms a secret was common practice in the early 1990s when the original TETRA algorithms were designed.
“[However], public domain algorithms are now widely used to protect government and critical infrastructure networks, for example AES [Advanced Encryption Standard], standardised by the US government. Effective scrutiny of public domain algorithms allows for any flaws to be uncovered and mitigated before widespread deployment occurs.”
According to Pasquali, meanwhile, alongside efforts by ETSI and its partners such as TCCA, the industry itself is also busy evolving the security piece on its own behalf. “Far beyond what the standards provide,” he says, “all the TETRA industries
have been making efforts to strengthen and protect their own solutions against cyber threats. That could mean both intentional [threats] and unintentional, like any other
ICT infrastructure.”
Moving onto hybridisation, meanwhile, Pasquali believes that interoperability between broadband and TETRA will be necessary for the foreseeable future, particularly when it comes to the public safety space. He cites many reasons for this, including questions around network resilience, availability of spectrum, as well as aspects of the functionality and standardisation piece, which is still very much a work in progress.
Discussing functionality in particular, he continues: “It is important to highlight that TETRA and broadband are not competing technologies. Rather, they complement each other, and it can be expected that both will be used together to provide mission-critical services.
“With the prospect of TETRA and MCX operating in parallel for many years, it’s clear that the interworking function is a crucial part of TETRA’s evolution. This is why ETSI’s TETRA interworking function has been conceived and published.
“The industry itself will continue to incorporate interfacing, interworking and gateway functionality into its products.”
The work on the TETRA Interworking Function (IWF) started in a TCCA Critical Communications Broadband Group (CCBG) task force, and has gained momentum with the aim of facilitating the transition from narrowband TETRA to broadband MCX. TCCA has now created a formal IWF working group to continue the work.
Asked how he believes that interworking will work from an operational perspective, Pasquali goes into more detail about functionality itself, including the ability to have “mixed technology talk groups” in the field.
“It will be a different story, however,” he continues, “for all the other features which are not covered by the standards but are still important. For instance, management and administrative stuff, around things like user privilege.
“If a unique management platform is desired by a specific user organisation, that would fall to individual industries to provide a propriety interface.”
Disruptive technology
Winner of the best TETRA solution category at last year’s International Critical Communications Awards, Teltronic’s MCBS base station is a product which is indeed helping to evolve the standard.
The device offers multi-TETRA carrier capacity as well as RF power of up to 40 watts, thereby – according to the company’s website – “matching the performance of cabinet format base stations in a compact unit of reduced weight and size”.
It accomplishes this through the use of software defined radio
(SDR) technology.
The website continues: “The great strength of the MCBS lie in the use of SDR technology, [enabling] the components that have been typically implemented in hardware [to be] implemented by means of software.
“Thanks to these SDR techniques, the MCBS is capable of incorporating up to four TETRA carriers, presenting itself in different configurations to be able to adapt to the characteristics of each deployment.” SDR also enables the unit to be configured and monitored remotely, via the use of the company’s IP infrastructure, Nebula.
Discussing the development of the product, Teltronic director of research and development, Alfredo Calderón, says: “The development of the MCBS started around 2018, and a little less than two years later we were presenting it at Critical Communications World 2020.”
He continues: “It is a truly disruptive product. Our goal was to match the performance of a fixed indoor base station in a single compact device that was ready to operate outdoors in the most extreme environmental conditions without requiring civil works for installation. This unit has changed the way TETRA deployments are made.”
Elaborating on the deployment piece, Calderón states that the ability to mount the unit on a mast or wall due to its size has simplified installation considerably. At the same time, “being able to operate with [both] batteries and solar panels” means that the MCBS doesn’t need to be situated in an environment with what he calls a conventional power supply.
“Moreover,” he continues, “as fewer units are required to cover the same coverage area, its use significantly reduces the cost of TETRA infrastructure. [It also] shortens deployment, maintenance and upgrade times, and reduces the carbon footprint.
“Also, in terms of energy, MCBS consumes much less power than a base station in a cabinet, to deliver the same number of carriers and RF power. This reduces the OPEX cost of operating the TETRA infrastructure.
“The MCBS has contributed significantly to the evolution of TETRA by driving innovation, optimising processes and creating new market demands.
“TETRA still has a long way to go, and we believe that its evolution will involve improving the efficiency of the systems and – in a global context of great awareness of environmental issues – improving energy consumption and reducing the carbon footprint of the systems.”
Coming back to our earlier discussions with Pasquali around the industry’s efforts in relation to security, meanwhile, Calderón also touches on the aforementioned Nebula infrastructure.
This, he says, is already certified according to the IEC 62443 security standard.
Another product paving the way for TETRA evolution is Sepura’s SCL3, which is a TETRA and 4G/5G handset, launched earlier this year. The company’s website describes the product as being “carefully designed to meet the needs of users at every stage of the journey to mission critical services [MCX].”
“It delivers,” the website adds, “everything you would expect from a rugged body-worn device, along with Android OS, a 5 inch display, an optional TETRA module, and extensive portfolio of accessories.”
While discussing the development of the SCL3, Sepura’s chief technology officer, Peter Hudson, makes explicit that technological evolution is always intimately bound up with user need.
He says: “The device concept came out of a market requirements research exercise spanning several years, involving discussions with end-user groups and staging workshops across our customer base worldwide.
“The results of this process enabled us to better understand the use-cases, how the devices will be deployed and what accessories and support services will be required to support the device when in use.”
He adds: “Introducing a new product with new technology and capabilities obviously offers new benefits and opportunities. However, the end-user also has to be able to seamlessly continue their day job while adopting the device and any new benefits or features it brings.
“That can take time, particularly given that [onboarding new kit] is not normally top of the priority list when
it comes to the day job. Therefore, the design of the product needs to facilitate that transition in as easy manner as possible.”
Hudson illustrates this further by hinting at a certain amount of back and forth taking place during the market research activities mentioned above, claiming that “we have seen requirements go full circle several times as our users develop understanding of their future device needs”.
One key outcome of these discussions, naturally, was the need for broadband-enabled functionality, such as data transfer, video and so on. At the same time, it was also clear that users wanted to undergo little or no disruption when it came to ‘business as usual’ working.
Hudson elaborates on this via a discussion of the SCL3’s push-to-talk functionality, with the device including a large button positioned similarly to the company’s other TETRA solutions.
“The devices also still have physical keys, so users can operate them ‘eyes free’,” he says. “This enables them to accept or reject a call without having to look at the screen. The keys are likewise programmed to do everything from sending a message to taking a photo with the camera.”
All this leads neatly onto a discussion of the transition to broadband in and of itself, which in the UK, of course, means the Emergency Services Network.
Discussing how the SCL3 might fit in with organisations’ procurement strategies, Hudson says: “From our point of view, we’re now getting close enough to broadband transition that this is about the right time [to launch the product].
“People are starting to understand what they’re going to buy, and how they’re going to use it.”
The foreseeable future
Earlier in the piece, TCCA’s Pasquali spoke of his belief that TETRA would remain the optimal mission-critical voice technology for many years to come. This was due to lingering questions around leveraging commercial broadband networks for mission-critical use, as well as the different needs and requirements of each country.
That being the case, how does he see this ultimately playing out a decade or even more down the line? Can he envisage a situation where some nations will simply refuse altogether to give up TETRA, choosing to run both technologies in parallel, in perpetuity?
Giving a background to this, he says: “It has become quite clear in the last few years that the replacement of TETRA is a much more complex task than [was originally] expected. There are many technical and operation considerations to address to make sure that any new network delivers the same mission-critical quality of service.
“For instance, all the elements of the end-to-end system must be made resilient, as well as being able to deliver high-density and robust communication even in the event of a crisis. This is particularly crucial, because in most cases, the user organisation and national administration are going to be using a commercial [broadband] network, which has been designed for a completely different purpose.”
He continues: “There are also many commercial factors to be considered. For example, all suppliers in the mission-critical ecosystem must clearly understand their responsibilities, dependencies and deliverables. And not all have the same expertise from that point of view.
“Once again, commercial operators don’t usually have any expertise of what the mission-critical service is. Therefore, the deployment and running of a mission-critical broadband service must be treated as any other ICT project, integral to which will be high-quality programme management. This is a very complex and long task.”
Last but by no means least, meanwhile, is that public safety users themselves invariably demonstrate – quite understandably – extreme reluctance to give up any frontline technology which they already trust. (This was certainly the case early on in the ESN project, for instance, as anyone who attended the British APCO event Home Office Q&A sessions at the time will remember).
Answering the questions posed above, Pasquali says these decisions will be entirely for public safety user organisations and their respective “national administrations” to make.
He is less circumspect when it comes to other mission-critical verticals, however.
He says: “The big push for the move to broadband has come from the public safety sector, particularly in relation to national public safety networks. By contrast, many other market sectors will probably decide to remain on narrowband, at least in the next decade.
“Voice services still represent the main operational needs for non-public-safety operations, after all. And TETRA is still the optimal solution for that.”
