From Voice-Centric to Data-Driven Critical Communications

Back in 2024, I came across an excellent GSMA APAC webinar looking at the evolution of critical communications from predominantly voice-centric systems towards broadband, data-driven solutions. I had intended to write about it at the time but, as often happens, it remained on my ever-growing list of potential blog posts.

Watching it again in 2026, what struck me was not how much of it had become dated, but how relevant its central message remains.

The transition is not a simple replacement of TETRA, P25 and other narrowband systems with 4G and 5G. For many public safety and critical industry users, the more realistic path is a long period of coexistence, convergence and interworking.

Traditional narrowband critical communication systems were built around some very demanding requirements. Coverage and availability must be there 24 hours a day, 365 days a year. Different agencies need to communicate during major incidents. Group communications are fundamental. Security, reliability and resilience are essential. Devices must also be fit for purpose, whether they are being used by police officers, firefighters, ambulance crews or workers in other critical industries.

Broadband does not remove any of those requirements. Instead, it adds another layer of expectations.

Public safety and critical industry users increasingly need access to high-resolution video, mapping, live location, sensor information, databases, drones, body-worn cameras and other sources of real-time information. Voice remains essential, but it is no longer sufficient on its own.

This is why 3GPP Mission Critical Services, generally referred to collectively as MCX, are so important. Mission Critical Push-to-Talk, Mission Critical Video and Mission Critical Data provide a standards-based framework for extending critical communications beyond traditional voice services.

The Critical Communications Association, TCCA, highlighted an important reality during the webinar. Narrowband and broadband systems will coexist for many years. Some organisations are augmenting existing systems with commercial mobile networks, others are deploying dedicated broadband networks, and many are adopting hybrid approaches combining dedicated, shared and commercial infrastructure.

There is no single migration model.

One of the most interesting examples came from New Zealand, where the Public Safety Network is being delivered across multiple components rather than as a single replacement network.

The narrowband element uses P25 Phase 2 for mission-critical voice, while the cellular element brings together coverage from the country's major mobile networks. The aim is to allow public safety users to make use of more than one network instead of being limited to the coverage footprint of a single operator.

At the time of the webinar, around 15,000 users were already using the cellular service and more than 430,000 roaming sessions had taken place without major issues. The combined approach was estimated to provide around a 5% improvement in usable coverage.

Interestingly, the improvement was not only in remote rural areas.

Many of the benefits came from small urban coverage gaps where one operator might have poor or no signal because of buildings or local radio conditions, while another operator remained available. For a consumer, this might simply be an inconvenience. For a first responder trying to access operational information during an incident, it can be far more serious.

The webinar gave an example of a firearms incident in a remote area. Only one officer present had migrated to the new public safety SIM, but that user had connectivity from an alternative network and was able to provide access for other personnel. This allowed the team to obtain information about the offender, access intelligence and maintain communications with the command centre.

Another example involved an ambulance crew using improved connectivity to help direct a helicopter to the correct location.

The next step was quality, priority and pre-emption. These capabilities are essential because access to multiple commercial networks is only one part of the problem. During congestion, public safety users need to receive the appropriate treatment ahead of ordinary traffic.

New Zealand was also looking at deployable coverage solutions for situations where cellular coverage does not exist or where infrastructure has been damaged by a natural disaster. Portable systems using satellite backhaul and local cellular coverage can be taken into the field and deployed by first responders without requiring a team of radio engineers.

This is an important part of the changing critical communications architecture.

Coverage is increasingly becoming multi-layered. A user may rely on a terrestrial mobile network under normal conditions, another operator where the primary network is unavailable, a deployable small cell during an emergency, and satellite connectivity when terrestrial infrastructure cannot be reached.

The same principle appeared in a very different example from Australia.

Icon Water provides essential water and wastewater services across the Australian Capital Territory. The organisation had been using an ageing voice-centric narrowband radio system and wanted to move towards broadband critical communications. The challenge was that around 30% of its operational area was not covered by terrestrial mobile networks.

Simply replacing the radio system with an application running over a commercial 4G network would therefore not have been sufficient.

The solution combined a dedicated MCX platform with multiple forms of connectivity. Where terrestrial 4G was available, users could connect through the mobile network. When vehicles moved outside cellular coverage, smart routers could use LEO satellite connectivity as an alternative backhaul path, with Wi-Fi providing local access for users and devices.

This is a good example of why the future of critical communications should not be viewed as a competition between terrestrial mobile and satellite networks. The two can complement one another.

The Icon Water deployment also demonstrated how broadband expands the communications environment beyond push-to-talk voice. The platform could support video, file sharing, emergency alerting, location information, lone-worker protection and integration with external systems such as body-worn cameras, CCTV, drones and IoT sensors.

At some fixed locations, in-building mobile coverage was also poor. Repeaters were used to improve the coverage at surveyed locations from around 12% to approximately 90%.

Again, there was no single technology solving every problem.

The wider webinar also showed how similar changes are taking place across other critical industries. Mining, energy, utilities and ports are increasingly using private 4G and 5G networks for applications ranging from low-data-rate sensors to high-definition video and remote control.

The Port of Port Hedland example included marine sensor connectivity, worker mobility and connectivity for visiting seafarers. The network had to cover operations extending beyond the traditional office or factory environment and out towards maritime areas.

Rail communications are following a similar path. The Future Railway Mobile Communication System, FRMCS, is being developed around 5G and MCX principles, supporting not only critical voice and signalling but also applications such as CCTV, passenger information, staff communications and future automation.

Some of the deployment timelines discussed in the 2024 webinar have naturally moved on since then, but the technical direction remains clear. Critical communications are becoming increasingly software-driven, data-rich and dependent on a combination of communications technologies.

5G-connected UAVs were another example. A presentation from China Mobile International looked at how network-connected drones could support emergency response, policing, firefighting, monitoring and other low-altitude applications. Instead of the drone being simply a remotely controlled flying camera, it becomes part of a wider communications and information system.

This brings us to what I thought was the strongest message from the panel discussion at the end of the webinar.

Dr Jolly Wong, formerly CTO of the Hong Kong Police Force, described the transition using two Cs: convergence and coexistence.

Narrowband critical communication systems remain highly relevant to organisation-centric group communications. They are built around reliable voice, established operational procedures and communication within defined groups.

Broadband, on the other hand, enables more information-centric operations. Users can access video, data, applications, sensors and other sources of information that improve situational awareness and decision-making.

The two approaches have different strengths.

The migration cannot happen overnight, so narrowband and broadband systems need to work together. Interworking between different systems, networks and groups therefore becomes an essential part of the transition.

Dr Wong used the analogy of yin and yang.

On one side are the traditional strengths of mission-critical voice: resilience, security, availability, reliability and consistency.

On the other side are the strengths of broadband and data-driven communications: multimedia, video, applications, IoT, AI, innovation and agility.

The future is not simply one side replacing the other. It is about finding the right balance between them.

This may also explain why the transition to broadband critical communications has taken longer than some originally expected. Replacing a consumer mobile service is relatively easy. Replacing a communications system that people depend on in fires, floods, terrorist incidents, accidents and other emergencies is completely different.

The technology must work, but that is only the start. Coverage, spectrum, security, interoperability, certification, priority, pre-emption, devices, applications, operational processes and user behaviour all have to be considered.

As critical communications become more data-driven, the network itself is also becoming less visible to the user. A first responder should not need to think about whether connectivity is coming from the primary mobile operator, another operator, a private network, a deployable system or a satellite link.

The objective is reliable access to voice, data and applications wherever they are needed.

Nearly two years after the original webinar, the move from voice-centric to data-driven critical communications is still very much a journey rather than a completed transition. Perhaps the most important lesson is that the future will not be defined by one network or one technology.

It will be defined by how well narrowband, broadband, private networks, public mobile networks and satellite connectivity can work together to provide the coverage, resilience and information that critical users need.

The full GSMA APAC webinar is embedded below.