An evolution of public safety communications from today’s TETRA mobile radio system towards a unified network solution combining TETRA with LTE was the topic for Richard Bennett on the Motorola Solutions stand.

“Everybody understands why we need TETRA private mobile radio for public safety; everybody understands mission-critical needs, security, resilience, coverage”, he said. “So we are talking about TETRA with TEDS and LTE working together. You create your own secure private data network for public safety and it gives you control of the operations around that network. So as opposed to having a commercial network which you are kind of using for public safety, over-the-top or just having a roaming agreement, it gives you complete control over what is going on.

“If you build a TETRA network now, you need to make sure it’s future-proof, future-ready. And that might mean having a physical network that’s built with LTE and TETRA in mind – you would have dual base station sites so you have the ability to use the same mast or base site for TETRA and LTE.

“When we talk about public safety LTE, we’re not just talking about a dedicated network. We are talking about a public safety core which gives you the ability to do things like multimedia talk groups, resource tracking – and it gives you the kind of functionality you would expect from a TETRA system. So it’s not just an LTE system – it’s public safety LTE with LTE core.

“Everything you would expect from a TETRA network, you can get from an LTE network with a dedicated public safety LTE core. For example, we have a partnership with Ericsson on LTE. One of my Ericsson colleagues talks about LTE being like a six-lane motorway. If it is commercial LTE, all six lanes could be jam-packed. If you have public safety LTE, you have the ability to put the blue lights on a message, clear the traffic and send it straight through! And that’s why you need a dedicated public safety LTE core.

“Rather than revolution, we expect evolution. So initially you could have a TETRA system and an LTE system. With the core that we have, you can plug it into a commercial RAN [radio access network] or you can plug it into a commercial network’s core. You have either option, depending on how you want to work it.”

Public safety core

Already Motorola Solutions is pursuing this approach in the US, where it has been awarded seven of the first nine contracts for public safety LTE deployments. “The one that is probably the most progressed is Harris County, which is Houston, in Texas”, Mr Bennett said. “As I understand it, the urban area is covered by the public safety LTE network whereas the more rural area of the county is covered by Verizon’s LTE network. So it’s about giving you that coverage.

“I see it working that way in most places. You could basically run a TETRA network, implement the public safety LTE core, plug it into a commercial network and then you could add your own dedicated public safety network at a later stage. So there will definitely be an evolution. I think most people will take a commercial network partner first and then build their own dedicated network. I think there’s going to be some caution. And also, spectrum: commercial spectrum is going to be available first.”