Fast wideband networks may be a mirage
Terrestrial Trunked Radio, or Tetra, will remain the preferred radio communication standard for internal security and emergency services, at least for the next 20 years, even if in the commercial sector wideband networks like Long Term Evolution (LTE) 4G are becoming a nearer-term reality.
The message coming from the Tetra World Congress, held in Dubai, United Arab Emirates, in May, is clear. Neither customers nor the industry have defined what they specifically want in terms of next-generation communications for fire and police forces. Meanwhile, Tetra-based systems are becoming widespread, year after year. Indeed, in many parts of the world the “migration” from analog to digital radio communication is still to happen. According to IP Multimedia Subsystems (IMS) researchers, there are still 23 million analog terminals in service against 13 million digital systems.
While there is growing interest in improving existing networks and adding capabilities by overlaying LTE on Tetra, so far operators tend to consider real-time video as a “nice to have,” but not a mission-critical feature. In turn, most existing operational requirements can be met by the current Tetra systems or its successor, the Tetra Enhanced Data Services (TEDS). TEDS increases speed and can add slow-video—5 frames/sec. versus LTE 20 frames/sec.—functionalities, wireless application protocol (WAP) and maps, likely satisfying 80% of the customer's core needs.
Beyond that there is LTE, but the public service community will find it difficult to secure enough dedicated bandwidth via national governments. The situation is even more complicated in Europe, where, according to industry sources, no decision on a common wideband will be endorsed for another 10-15 years, at best. Not surprisingly, some European countries are tempted to go it alone, as happened before for early digital radio systems. Some government bodies are unwilling to upgrade their network to TEDS and are still betting on LTE, or at least a commercial version initially. Others, as Norway has done for its national network, think LTE is still too far in the future, and for a limited investment it is more convenient to simply upgrade Tetra and obtain much of what the operators would like now.
Industry, of course, would like to see a single wideband frequency set aside for public emergency use worldwide. This would bring down costs and better exploit research and development investments. But it would be a miracle if a world standard emerges any time soon.
Still, some of the main communications companies, including Motorola Solutions and Selex Elsag, believe that professional operators could exploit commercial LTE, even if not fully integrated. Selex, for instance, unveiled in Dubai its Professional and Emergency Resilient System Enabling Ubiquitous Service, which allows integration of different access technologies for voice, video, multimedia and data communications. Alcatel-Lucent and- Cassidian have instead proposed two different “combined” systems, one working at 400 MHz the other at 2600 MHz. But while potential customers are interested, sources say, most of them are waiting for the commercial world to develop LTE infrastructure with widespread coverage instead of paying for their own private LTE.
Tetra remains a valid mid-to-long-term answer, which is why Motorola Solutions has introduced a new radio line, MTP 3000, which goes “above” pure Tetra specifications with a 2-dB gain improvement and transmitting power up to 1.8 watts, for a 14% range increase and up to 30% better coverage.
But there is another facet sustaining Tetra business. So far, no one seems ready to provide a Tetra radio terminal combined with the functionalities and the screen of a personal tablet. In fact, the tendency has been to equip personnel with separate devices: a Tetra radio and a rugged, tactical tablet. In Dubai, Motorola introduced its LEX 700 tablet, which brings full LTE and a full keyboard. But some operators insist that while losing an LTE tablet's connectivity would be bad, losing the Tetra radio could cost lives.