Beyond TETRA

A session on the future shape of mission critical communications for the UK’s emergency services held at the British APCO show hinted at a probable broadband solution, but left many public safety practitioners looking for further reassurance, reports James Atkinson

Beyond TETRA

The UK Government is currently trying to identify the future shape of mission critical communications for its Blue Light services under the Emergency Services Mobile Communications Programme (ESMCP), which is likely to go out to tender in 2015.

At the moment, the police, fire and ambulance services receive voice and limited data services from a private, dedicated TETRA two-way radio network, funded, built and managed under a private finance initiative contract by Airwave Solutions.

Contracts with Airwave will begin to run out in 2016 with the last ones terminating at the end of 2020. The received wisdom is that at some point in the future the emergency services will augment and eventually replace existing TETRA narrowband services with broadband services – most probably a form of the cellular radio standard 4G LTE (long term evolution).

This can probably only be provided by a partnership of existing commercial cellular operators, as a direct result of cost constraints (the equivalent of the PFI investment presently on narrowband), as the US experience has shown.

Mission critical LTE

The Critical Communications Broadband Group (CCBG), a Working Group of the TETRA + Critical Communications Association, is working with the standards body 3GPP to incorporate mission critical functionality into the LTE standard. 

CCBG has identified four key areas to be addressed within the LTE standards to enable a suitable foundation for critical communications services. These are:

Group communications system enablers for LTE

Proximity-based services 

Public safety networks resiliency

Push-to-talk (PTT) voice application standard over LTE and its evolution toward multimedia (voice, data, video, etc.) group communications.

In March this year, CCBG published a timeline for when these key functions might be incorporated in the LTE standard. It believes that LTE-based data services for mission critical communications will not be available until 2018 at the earliest and that acceptable quality voice services over LTE for mission critical users are not expected
until at least 2020.

What is clear, therefore, is that the range of essential mission critical functions provided by TETRA, and deemed necessary by the emergency services to do their job, will not be available on LTE by the time the ESMCP contract has to be let. What then is the UK Government to do in the interim? Another equally vexed question is: who will provide the broadband network for the emergency services? 

The two main choices are: build a new dedicated broadband network for exclusive use by the emergency services and perhaps other organisations and industries deemed vital to the national interest; or, use an existing network supplier – probably one or more of the UK’s commercial mobile phone operators, who are currently building out 4G LTE networks.

The first option (provided the spectrum can be found to run the new network on – see box) ensures the emergency services have a robust and resilient network that they can control. But it will be very expensive to build and the UK exchequer is hardly overflowing with surplus cash at the moment.

Commercial options

The second option makes use of existing commercial cellular networks (and potentially Wi-Fi), but ones that lack the necessary resilience for mission critical services. A major concern for public safety organisations with this arrangement is that it may not give them enough control of spectrum resources when they need them.

What became apparent at the B-APCO session, if unsaid directly by anyone, was that if the emergency services want access to broadband data services in the near future, then there is only one realistic bearer option – namely, commercial mobile operators.

The O2 and Vodafone representatives at the session explained that their joint Beacon project would provide 18,500 2G, 3G and 4G masts by 2015. Voice over LTE services would be available by 2015 for the emergency services, but what this means in reality is a fallback service to 2G/3G.

Very little detail was offered on just how commercial bearers would go about providing the public safety community with the services identified by CCBG above; or how, or when, they would meet the requirements for a resilient network.

What was clear from the audience questions is that there is considerable unease among public safety professionals as to the current fitness for purpose of the LTE standard and the adequacy of using commercial bearers. 

Speaking to Wireless after the event, British APCO chief executive Tony Antoniou, summed up this concern by saying: ‘There is a huge credibility gap. Technologists have their clear vision of how the mission critical capabilities can be provided over a new technology like LTE. But unless they can engender belief and assurance, among the professional practitioners of public safety, the gap can generate damaging doubt.

‘So, some intense work is needed to reassure our community as to how and why the technology works and is able to deliver the service that we need to save lives on a 24/7 basis, irrespective of any scenario, including 7/7 and worse.’ 

Antoniou points out that if commercial networks are used then Quality of Service (QoS) will be one of the most critical factors in maintaining the emergency service ‘pipe within the pipe’ that represents both a guaranteed ‘amount’ of throughput, and provides priority over other traffic types and other sources and destinations. 

Quality of service

‘QoS works,’ says Antoniou, ‘but it’s only as good as the implementation. We need reassurance here. We also have a huge gap in belief.’ Public safety users will need to be convinced that their commercial partners will recognise when their priority is paramount. The concern is that commercial networks will be reluctant to override the needs of their large corporate customers and ordinary subscribers.

To provide this reassurance Antoniou believes QoS must be backed up by some serious law, but are there any existing written legal precedents that can be used as a model? He also questions who is going to ensure that this is fit for purpose across all the component services and agencies.

Antoniou feels strongly that if the emergency services are to make a major step-change to a new technology by 2016, then all parties need to get behind it to make it a success. A great deal of work needs to be done to ensure the right technical solution is established and underpinned by the right legal framework. 

Above all the emergency services need reassuring that the tools they are going to get are the right ones for them to continue saving lives. The culture change will be considerable, so Government needs to take the emergency services with them when it finally decides on what its ESMCP solution will be.

To do this he says Government must mandate the successful implementation of what he calls the four Cs: 

Capacity

Capability: the minimum requirement is the capabilities public safety has today with TETRA – talk groups, red button, push-to-talk, priority, pre-emption, etc

Coverage: solid reassurance that if anything coverage will benefit from moving to a new technology – e.g. better in-building coverage and it ought to cover existing challenges over coverage in remote locations, open spaces and locations incorporating critical national infrastructure and assets 

Criticality: a guarantee that when the emergency services need the network it is there and they can do what they need to – priority, pre-emption, smart implementation of QoS etc; resilience – that there is a planned fallback if emergency service communication devices do not work, so they can still save lives.

‘My own view is that we haven’t got to get into a crusade here. I think these messages are already understood, but it is not just a case of implementing a clever technical solution; hearts and minds need to be won, so the support of all parties is really necessary,’ says Antoniou.

‘We think B-APCO can help here and we are actively planning events to help people understand the issues. We have close ties with the APCO in the US, so we hope to bring experiences and learnings from the roll-out of the US FirstNet LTE public safety network to the UK.’

Written by Wireless magazine
Wireless magazine

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