Combined PMR and cellular is the future for critical comms

These are interesting times for suppliers in the narrowband two-way radio market. Their traditional customers are increasingly looking to see how they can access the multitude of data applications readily available to consumers via cellular broadband and Wi-Fi networks. How do they enable this while still providing all the benefits that private two-way radio networks provide?

Ross Spearman, the new chief technology officer of professional mobile radio (PMR) vendor Tait Communications, certainly has a view on this as he has spent much of his professional life with Ericsson, the largest supplier of cellular infrastructure to the mobile phone industry.

Speaking to Wireless earlier this year, he observed: ‘What was interesting for me coming from a 3G and 4G cellular communications background was that I came into the PMR world with a “why not just use LTE for everything” mindset.

‘But the more you learn about PMR the more you realise that these two things are quite orthogonal. PMR has huge coverage, very high reliability and very low capacity, and the other is exactly the opposite, smaller cells, high capacity and let’s say consumer grade reliability. What is obvious to me is that if you put the two together you would have a really good network,’ says Spearman.

He adds that he has heard a lot of ‘either/or’ discussions when it comes to the two technologies, but to him this does not seem to be a sensible argument. ‘It would be better to use a combination of both,’ he asserts, pointing to the example of a New Zealand utility Tait is working with that has deployed both Digital Mobile Radio (DMR) and LTE base stations to both augment coverage and to be able to run data applications.

Unified comms solutions

‘At Tait we have the UnifyVoice solution,’ points out Spearman. UnifyVoice integrates push-to-talk over broadband cellular (and Wi-Fi) with Tait narrowband PMR systems. This has now been extended to vehicles with UnifyVehicle.

‘The solution enables radio users to extend coverage outside of PMR range, and allows those without radios to communicate with PMR users, and that seems to me to be exactly how it should work,’ says Spearman.

Judd Cain, regional manager EMEA at Tait, adds: We have customers in all the different verticals we support who already use cellular mobility and PMR today and have been for a while. They are using smartphones, maybe with some applications on top, or they are using them to make calls in areas where they do not have PMR coverage, such as at the bottom of the car park or shopping mall.

‘Seamless roaming is a really nice application for keeping people connected and it keeps users off the mobile network, as that’s what costs the business money. You use it when necessary, but it is not always required. So both user management and resilience is addressed. It is quite an elegant solution that we have evolved further over the last year since it was first launched.’

Spearman observes: ‘The key thing here is that communications shouldn’t be limited to just PMR and cellular. The main thing is getting access to whatever connectivity is available in the background. The user shouldn’t need to know what the bearer is; they should just be able to push the button.

‘Take an emergency room in a hospital; that tends to be quite well shielded, so you might not get cellular or PMR coverage, but it is likely they will have Wi-Fi, so there is no reason why your radio shouldn’t switch over to Wi-Fi.’

Tait’s aim is to evolve the solution to the point where when the user pushes the PTT button, the intelligent UnifyVoice software automatically detects the best available network and connects the user by pairing a smart device with a radio, so users can move between radio, cellular and Wi-Fi. When the PTT button is pushed, the intelligent UnifyVoice software will automatically detect the best available network and connect to it.

Bearer choice

‘The great advantage of UnifyVoice in the wireless world,’ points out Spearman‘ is that if you are on a 4G network you are in a “break before make” situation where you need to be on this network or on that network. But if you have a radio and a cellphone you’ve got two networks up at the same time and you don’t have to jump blindly between them. You can choose which one you want based on signal quality, or enable streams over both networks to make sure you get the best connection.’

He adds that there are several different ways of automatically selecting the best bearer network depending on whose infrastructure, network and radios are involved. ‘You can either do it at the start of the call by looking at the signal strength, quality and so on. Or you can look at a pre-set policy and decide which way to go.

‘Or with our seamless solution we can send streams over both the PMR and LTE networks in parallel. As both streams come back into our PMR network we can then choose which has the best quality. We can do that on a 20 millisecond basis and switch between the two streams such that the network changeover is completely seamless to the end user,’ explains Spearman.

Jamie Bishop, EMEA marketing manager at Tait, adds that there is a cost discussion to be factored in here too where for economic and mission critical reasons you might use one bearer or another at different time and for different applications. You might want to keep mission critical transmissions on PMR and push less mission critical traffic off to cellular, for example.

‘And it is not just about the wireless side,’ he points out. ‘It is also about leveraging the value of the interface of the smartphone to access pictures, maps and other data applications, so you can really make use of that capability. If you look at Transport for London, since 2007 they have had GPRS for data running on the buses. The difference now is that you can provide that service to a user walking down the street, whereas before you needed several devices to do that – and now you can combine all that with a PMR system.’

Working with end users

Tait has some of its people embedded with the New Zealand police to help them figure out the right interfaces and see what works best for them in operational terms. Spearman thinks the way the police work will change hugely thanks to new communication technology. ‘The police study we are doing is all about ensuring officers can use the equipment while keeping their eyes up focused on the suspect.’

But police now have two devices – a smartphone and a two-way radio. The question is how the radio with its big battery pack and 5W output can best be integrated with the smartphone. Perhaps all that is required is a PTT lapel mic with UnifyVoice capability, which could be the interface for everything – not just the radio.

Spearman suggests that applications like voice recognition for things like status reports could cut out the need for bringing in dispatchers, although it will still need a connection to the network.

‘You could embed a very small set of phrases into the microphone, like “I want to run a numberplate check”, and the application would convert the speech to text then transmit that over the LTE or LMR network. The requisite data base takes the request, sorts it out, and sends back an answer either as text or speech without the need to involve a dispatcher,’ he says.

‘All of this is about meeting the user experience and providing the right form factor for the role,’ interjects Cain. ‘Some users will still need the traditional brick-style radio for IP67 protection reasons, for example. But others won’t need that, so we might see a real explosion in form factors coming down the line.’

Internet of Things

This kind of technology is also important in the M2M space, which uses this kind of messaging. Tait has developed its GridLink solution for distribution automation in SCADA systems for use by utilities in particular.

Spearman cautions that you have to careful with Internet of Things applications because of the huge range of disparate use cases. ‘For some applications the “dollar values per bit” is extremely high, so organisations are willing to pay that to ensure critical infrastructure works. But for accessing data from temperature sensors in a vineyard you need a very different cost model.’

Many IoT applications are connected to equipment with 25 to 50-year lifecycles, so the IoT devices monitoring that equipment must have a long life too. Bishop says: ‘A lot of companies and utilities of different types have invested in cellular technology, 2G GPRS in particular, but in some countries mobile operators are turning off their 2G networks and are refarming the spectrum.

‘So, the end users that have relied on those 2G networks are trying to re-align themselves. What they want is security of supply for a long time and a lot of the devices they have installed have only been out there for five years, so having to replace them all with a different connectivity IoT device is way out of whack for what they need.

‘The last thing they want is to have to replace all their wireless devices out in the field every five-year regulatory period. The other key driver for utilities and power companies is to reduce the outage penalties. By meeting the outage restoration targets they can save millions by just investing in a few thousand IoT devices,’ says Bishop.

Critical comms supplier

To Spearman what this means is that Tait is not in the DMR and P25 radio business; rather it is in the critical communications business. ‘It is not about building radios, it is about providing a solution. We are the glue between the networks.

‘No, we are not going to build an LTE base station and go into competition against Ericsson or Nokia, but we still expect to look after the same people we always have. Now it is more about what you put at the ends of the radio system, than the radio system itself.’

Cain adds that the closer Tait is to its end users the better it is for them and the company’s resellers. The point being that Tait has the expertise and critical communications know-how from working closely with those end users for years. Mobile operators and some of their key vendors lack this knowledge and this is where the likes of Tait can help.

Spearman acknowledges that the company must continue to evolve its hardware to make sure it is state-of-the-art and up to date, but more and more it is the software capabilities in the radios and interfaces into back office systems that will differentiate it.

‘I took a look internally when I arrived at Tait and the majority of our R&D spend is on software development, so adapting to this new world is not such a change as you might think for a PMR vendor. The difference is that we are writing code that end users interact with. It may only have been a couple of lines on a radio display before, but now we are writing code for smartphones that makes the apps work.

‘So, that is different,’ he acknowledges, ‘and that is why we are working closely with police and utility companies to make sure we tailor our solutions closely to what they need. There are many different roles within the police. For example, a covert officer might want to have a PTT app open, but he wants it to look like he is on Facebook, so nobody knows what he is up to.’

Cain adds: ‘Yes, our core competency is hardware, but it is really about understanding how something is going to be used by the end users. We have to create something that really makes them safer and work better, so that’s why we work closely with them.’

New attitudes

In the past, the likes of Tait were dominated by radio engineers, but that is changing over time. Spearman points out that his future technology team uses a lot of interns who come in with completely different ideas about how things should work and with very different expectations.

‘They have no patience for doing things the old way,’ he says. ‘Take something like that voice to text app I mentioned earlier. A recent graduate will just go on line, grab some software and set up a demo, and ask: is this what you mean?’

How about the sales channel and the resellers: are they keeping up with this change? Cain says the company has to strike a careful balance, as a lot of Tait’s customers are not looking to jump straight into the next technological innovation all the time.

‘Change is good,’ he asserts, ‘but resellers help to moderate the pace of change by telling us what end users are ready for. But our end mission is to deliver the communications that they need and can use.’

Affirming this, Spearman adds: ‘I was in Orlando, Florida recently with our US dealers and the feedback was phenomenal. They said: when we met you two years ago and we gave you a list of the areas in your portfolio that needed filling, you’ve done it. So, when we spoke to them about UnifyVoice and the future they had no trouble taking that on board at all.’

‘But they are also building services and apps around our products,’ says Cain. ‘We have no monopoly on good ideas as we have seen in the UK and other markets and that is heartening to see, so I think our reseller community is on board with this new world.’

Spearman concludes: ‘It’s an exciting time to be working with PMR and maybe that’s not something I’d have said two years ago. There are all sorts of things coming in the area of personal area networks and the same for vehicle area networks, along with the whole software development and software controlled world.’

Image Credit: Billion Photos / Shutterstock

Desire Athow
Managing Editor, TechRadar Pro

Désiré has been musing and writing about technology during a career spanning four decades. He dabbled in website builders and web hosting when DHTML and frames were in vogue and started narrating about the impact of technology on society just before the start of the Y2K hysteria at the turn of the last millennium.