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Migrating to digtal

When a group of leading mobile radio fi gures met at Land Mobile’s table last month, the topic was how digital technologies will address users’ requirements

table session in London at which some leading personalities from the mobile communications world off ered their perspectives on the future of the technology and considered some of the questions yet to be answered. T is time there were no direct comparisons


of the various digital PMR technologies avail- able on the market; instead, participants con- sidered the wider aspects of digital, including future communications needs, the balance be- tween voice and data requirements and – inevi- tably – the need for spectrum. First to speak was David Taylor, of the tele-

communications consultants Analysys Mason, who provided a useful summary of the reasons for moving to digital, both technical and com- mercial. But he opened lightheartedly with a very brief history of radio. “When you think about it, it has gone full circle”, he said. “T e fi rst Marconi spark transmitter was digital: ones and zeroes. A colleague of mine pointed out that it is also broadband – spread spectrum!” More like smeared spectrum, someone ob-

served, unfeelingly. But Mr Taylor went on: “It is an important factor. Analogue radio trans- mission is ineffi cient and digital can occupy the spectrum much better. So that’s why digital has come along.”

or Land Mobile’s third Migrating to Digital event, the format changed from conference presentations to a round-

For the user, he said, digital radio meant in-

creased functionality and clearer voice, though not necessarily range (digital tended to fall off abruptly at the edge of the coverage area) and it was better for the non-expert user. Most sig- nifi cant was easy integration with the growing wealth of IP data applications, plus encryption. With the coming of the Data Protection Act, encryption was penetrating more and more towards the end user. In particular, there was now a responsibility to protect personal data – for instance, when sending patients’ medical records to an ambulance paramedic.

Showing a benefi t For the regulator – in the UK, Ofcom – dig- ital’s better spectrum effi ciency would allow us- ers to be packed more tightly into the available channels. And when we eventually reached an all-digital radio environment, it should be pos- sible to control interference better. For employers, digital will allow closer con-

trol of their workforce. “T e workforce doesn’t like to be controlled but it is important”. Mr Taylor said. “If you can actually show that they are making a benefi t, they will embrace it. I remember we did some work on the West Midlands Gas in introducing data, and when they found they could do to more jobs a day, and it meant they were getting more money, they were very keen to have the data system.

‘We don’t really have the take-up of the small or the private Tetra systems that are commonplace in Europe and Asia’


Whereas if they thought it was intrusive and going to trap them, they didn’t want it.” Yet data transmission does not meet every

communication requirement and instant voice contact will remain vitally important in many applications. “If you are in the warehouse and there’s a forklift truck moving and you can see somebody in the way, sending a text message doesn’t really work”, he went on. “Data is im- portant, but voice – whether it’s analogue voice or whether it’s carried over voice-over-IP – has got a function in business radio.” Why, then, should users migrate? Mr Taylor

off ered several possible reasons. T eir equip- ment might be outdated and expensive to maintain. Newer equipment would be greener, with lower support costs, and would occupy less space on the fl oor. T ere might not be enough channel capacity to expand. Or busi- ness needs might have changed.

Access to spectrum But while digital is making headway into ‘con- ventional’ PMR installations, lack of spectrum in the UK is a barrier to its use for large net- works. “We don’t really have the take-up of the small or the private Tetra systems that are com- monplace in Europe and Asia”, Mr Taylor com- mented. “T ere’s a lot of municipality systems, a lot of small transport systems. In the Middle East, we are seeing refi nery systems; an awful lot of Tetra. One hospital in Australia has got a three-channel Tetra system. We are not seeing that in the UK.” Instead, Mr Taylor regards DMR – the ETSI

TDMA standard which fi ts two time-slots for voice or data into a 12·5 kHz business radio

LAND mobile October 2011

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