PMR Summit: Bringing broadband LTE and PMR together

The hot topic at this year’s PMR Summit/Professional LTE event was how broadband services can be brought into PMR. Cassidian’s Philippe Devos, who chairs the CCBG Working Group for Systems & Architecture, brings James Atkinson up to date on the work to develop common global mobile broadband standards and solutions for mission and business critical users

PMR Summit: Bringing broadband LTE and PMR together

The search to find a way to bring broadband solutions into the mission and business critical environment has been a hot topic over the past few years, as users watch the ever-increasing rollout of commercial 4G LTE services across the world.

The TETRA and Critical Communications Association (TCCA) has identified 4G LTE as the most likely broadband solution. The problem is that at present LTE lacks many of the particular capabilities required by mission critical users, which are provided by narrowband digital standards such as TETRA, Tetrapol and P25. 

To tackle this problem the TCCA set up the Critical Communications Broadband Group (CCBG) earlier this year to provide a forum for the different mission and business critical user groups to articulate their needs to standards bodies, regulators, national governments and the EU. 

Working groups

One working group, chaired by Hans Borgonjen of the Netherlands Police, is collecting the user requirements. Another, chaired by Jason Johur of Motorola Solutions and Robin Davis of Actica Consulting, is preparing the Strategic Case to present to the EU, governments and national regulators.

The third working group covering Systems & Architecture is chaired by Philippe Devos, VP market & technology – secure communications at Cassidian. Its job is to incorporate mission critical features into the LTE standard as it evolves. To do this it is engaging with the 3GPP partnership of international telecoms standards bodies, which sets the standards for LTE, and ETSI (European Telecommunications Standards Institute), which manages TETRA standards.

The CCBG’s aim is to include at least some of the key functional and performance enablers for Critical Communications in the next evolution of the LTE standard, 3GPP Release 12, which is due to be published in Q2 2014.‘We need enhancements into LTE to allow it to support mission critical communications applications such as TETRA, Tetrapol, P25 and GSM-R, for efficient group communications,’ says Devos. 

‘So, in the first part of this year, we have established working groups and we have posted our first contributions to 3GPP Stage 1 Release 12,’ says Devos.

Group communication

Key work items that need to find their way into the LTE standard include efficient group communication (e.g broadcast feature for voice) and proximity services, such as direct mode operation, as the need for users to be able to communicate with each other at an incident even if they are out of network coverage is viewed as essential. Both are common features of the way that mission critical users typically work today when using PMR systems.

A third item covers how to implement a resilient architecture – a key requirement for mission critical communications. CCBG introduced a contribution describing group call requirements when an eNodeB becomes disconnected from the EPC (e.g link broken) and provides local services only.

One other aspect focusing on the user equipment and worth noting is the introduction of a higher-powered class of device (> 1 watt). The LTE standard for mobile phones is designed around low-power devices, but professional mobile radios operate at a higher power, so this kind of device should be included in the LTE standard to provide efficient coverage in rural areas or for direct mode operation. 

The point is that mission critical networks have to be available to the emergency services everywhere geographically. An incident cannot be moved. ‘This is why we can’t rely on commercial mobile services as currently deployed for mission critical use: they are not available everywhere and are not resilient enough,’ says Devos. 

Capacity limitations

Of course, there are various ways to overcome these coverage and capacity limitations, for example, in using deployable eNodeB on a truck, as described in the resilient architecture work item. 

‘The purpose of this group (Systems & Architecture) is to prepare contributions to 3GPP working groups with one single powerful voice, because we have already reached agreement on what we need,’ Davos says. 

One important discussion now under way centres around trying to define what the borders are between the 3GPP domain and PMR applications. The CCBG is contributing in this consensus building process for the functional split between the two domains says Devos.

‘This is very important for the situation in Europe, where there currently exists a large installed base of [TETRA, Tetrapol and GSM-R] networks. We will have to manage the co-existence of these networks for many years while we manage the migration to broadband-dedicated networks together with the use of commercial services for some non-critical applications,’ he says.

Further, the emergency services and business critical industries need to document their needs for multi-media applications, but the challenge here is that some of those needs are still unknown. ‘New ways of working in communications with video in 10 years’ time is something that is not known today,’ points out Devos.  

Moving pictures

He has some doubts about the validity of transmitting video footage to public safety personnel at the scene of an incident. ‘It means that the user will need to stop working to watch the video, but from an operational point of view it’s very different with voice because you can listen and have your eyes free to do what you need to do.’

The key issue is about selecting the right contextual information for the right people at the right time. Otherwise personnel are looking at video, but have no idea what to do with the information. 
If multiple media-rich communications are all trying to connect simultaneously then there will be severe competition for the available bandwidth, which will be overwhelmed as a result and collapse.

‘We have to have a layer that prioritises the traffic according to the criticality of the missions being undertaken by the groups and the ability to broadcast voice and data information to specific groups, areas of incident or responsibility, as we have in our systems today,’ explains Devos. 

Devos believes that this PMR-LTE interface is a reasonable request to make to 3GPP and that is what the CCBG contribution describes. ‘As with voice, we need a mission critical communication application domain with an interface to the enhanced 3GPP domain to support our future critical communications.  

‘The good news is that we have started and the way it is done will provide native interoperability, smooth migration and preserve the investments of our customers. I think globally we have made progress,’ says Devos. ‘Just two years ago we could not imagine having this discussion in 3GPP, so I am more optimistic, but it takes time.’

The other challenge is to persuade European governments and the EU of the necessity to continue investments in their existing networks for use by mission critical users and business critical industries and to integrate new broadband capabilities. But in Europe that means more spectrum will have to be found – and that will not be easy. Devos say the CCBG is now fully engaged in drawing up the strategic case to justify the implementation options for mission critical broadband networks and is preparing the standards requirements for 3GPP. 

Cohesive vision

Devos laments the lack of cohesion and political vision in Europe, pointing out that China has already developed a strong view of the need for broadband for security. It is rolling out 200 sites for broadband in Beijing already. The USA has allocated 2 x 10MHz of spectrum and $7bn (£4.4bn) towards its First Responder broadband network.  

‘Maybe we need to not just get the political support, but turn broadband networks into an advantage for the economy and this is what the CCBG business working group is trying to get positioned as a strategic case in front of decision makers,’ he says. 

‘We need to make sure we also have funding available not just for spectrum. We have to solve a political problem. We have to connect this to the political agenda – broadband for critical users will provide better connections, energy protection, boost the economy – we need to find a champion in Europe,’ concludes Devos.

Written by Wireless magazine
Wireless magazine

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