TETRA poised to take on the world

This overview of TETRA was one of the 26 or so papers on a range of diverse topics that were presented at RadioComms Connect in Melbourne.

What do the following places have in common: the Rio Tinto Mining Group in Perth, the Pacific Fair Shopping Centre and the Hyatt Regency Sanctuary Cove resort hotel on the Gold Coast, and the metropolitan area of Auckland?

They are just a few of the places that operate with the help of TETRA communications. TETRA (terrestrial trunked radio) is the digital trunked professional mobile radio standard developed by ETSI, the European Telecommunications Standards Institute.

TETRA systems are in use across the world, providing secure and robust communications for an increasing number of sectors including public safety, utilities, government, the military, oil and gas, railways, metros, airports, sea ports, hospitality and leisure organisations and many other commercial and industrial organisations.

In the early 1990s, a proposal was made to ETSI to develop a standard for providing a more efficient digital technology for the users of private mobile radio systems. Although initially aimed at shared systems for commercial users, this was later modified to include public safety users and public safety rapidly became TETRA’s largest market.

The technology was initially aimed at satisfying the needs of the European users but ETSI is a developer of standards for world markets, as is evident with such technologies as GSM, and so TETRA was firmly aimed at an international market.

Following much discussion about the relative merits of FDMA (frequency division multiple access) and TDMA (time division multiple access) technologies, the ETSI working group eventually settled on a four-slot TDMA technology based on 25 kHz channels. This was quite forward thinking in those days as it was the first technology to provide good quality audio in 6.25 kHz equivalent channels.

That is four times more efficient than GSM.

Like most PMR technologies, TETRA was aimed at those who work in groups, and therefore need to communicate in groups.

Around the same time, the TIA (Telecommunications Industry Association), the US standards body, was developing a digital technology, this time specifically for public safety use. This became known as Project 25. TIA decided on FDMA technology and this was probably a sensible decision based on its particular user requirements.

I am often asked whether TDMA is better than FDMA or vice versa. Both technologies have their advantages and disadvantages, so no-one can really argue that one is better or worse than the other. It depends on the application.

The TETRA Association, formerly the TETRA MoU, was created by several organisations that were keen to see the ETSI TETRA standard become widely adopted. This was back in 1994. In the beginning the focus of the organisation was to promote the standard, initially within Europe but later throughout the rest of the world.

However, for TETRA to be a success it needed more than just a good set of features. There were several extra ingredients that were vital if TETRA was to go global.

Spectrum is of course a vital ingredient and it was decided that TETRA would offer the greatest benefits if it had dedicated spectrum. Negotiations were held with NATO and with the regulators and, initially, spectrum was made available in the 380-400, 410-430 and 870-921 MHz bands. Since then, TETRA has also been implemented in the 450-470 and 806-870 bands. In China, the public safety bands around 350 MHz have been used.

In theory, TETRA was specified to operate anywhere between 300 and 1000 MHz. More recently there has been some interest in using TETRA in the 200 MHz bands. It is probably unlikely that it would be taken down below that for the time being.

Just as important as spectrum, the early members of the TETRA Association were convinced that, for the system to be a real success, it needed to be supplied in a healthy and competitive market and so this has been one of the association’s primary aims.

The association set up an interoperability process which defines in great detail how equipment should be configured for each of the different pieces of functionality. A testing and certification process is run on our behalf by the Italian government test house ISCOM.

It witnesses and corroborates tests of actual terminals that are taken to different manufacturers’ infrastructures to test true interoperability. It is clear that the open market created by this process has been fundamental to the widespread adoption of TETRA.

Both ETSI and the association are determined to ensure that TETRA has a long-term future and that ongoing development is in place to ensure the standard remains relevant to market needs.

An example of this is the ETSI project known as TETRA Release 2, which looked at a number of enhancements to the existing standard including new codecs and range extension. However, probably the most important enhancement was a high-speed data capability, now known as TEDS: TETRA enhanced data service. This will provide data rates up to around 600 Kbps.

It is actually a suite of data services, with data rates depending on the modulation scheme chosen and the available channel bandwidths.

The table shows the data rates available from different modulation schemes and different channel bandwidths. So far the most popular channel bandwidth used has been at 50 kHz giving data speeds up to 160 Kbps. This provides a very usable transport rate for many applications.

ETSI and the association are in the early stages of a new project to provide users with mobile broadband capability. We will be looking at other broadband technologies such as WiMax and LTE to see how they might integrate with TETRA or whether a bespoke solution would be more effective.

It remains to be seen whether it is viable to build discrete networks based on these technologies and no decisions on this have been taken yet. Defining user requirements is not easy and this is crucial to ensuring that we develop the right technology.

Another initiative is to look at the concept of software defined radios (SDR). These are devices that replace the hardware components of a radio receiver and transmitter and replace them with software algorithms, producing a highly flexible radio that can tune to any band and receive and transmit different protocols.

The next logical step is to have what is called a cognitive radio. This is one that scans around to see what spectrum is unused, what technologies are appropriate and then intelligently uses the spectrum.

TETRA is one that has been considered a candidate technology for SDR and cognitive radios and the association has joined a new project in ETSI called Re-configurable Radio System or RRS.

One of the association’s major focus areas is spectrum availability and this is arguably our biggest concern. With the expectation of increasing demand for data services in the years to come, the association has been lobbying hard for new spectrum, especially for future broadband services.

Regulators in several countries are trying to decide what to do with the so called digital dividend. That is the spare spectrum that will be released from within the 500-900 MHz channels by the switch-off of analog TV services.

As one might expect there is strong lobbying, from mobile operators especially, for mobile TV. There is also substantial pressure to use this spectrum to provide wireless internet services especially for rural areas. However, the public safety community has now taken up this fight and is working hard to obtain some of this spectrum for future public safety services, especially for broadband data.

Traditionally a public safety communications system, in the last few years TETRA has expanded both its markets and its appeal. I have outlined here a very few of the thousands of applications.

China Light and Power, now known as CLP, uses TETRA not just for voice but also to control its transmission network.

The Russian Federal Space Agency is using TETRA at the Baikonur Cosmodrome in Kazakhstan. Perhaps a time will come when we find TETRA in outer space Â… I am not sure how the spectrum regulators would deal with that situation!

The world’s largest flower auction run by Flora Holland is another user of TETRA. This organisation sells more than 12 billion flowers each year with a turnover of $7 billion, so it is not a small business.

It is a big responsibility to look after the safety and security of visitors, competitors and staff at a major sporting event. At the Pan American Games in Rio de Janeiro, a TETRA system did just that; and, of course, TETRA helped to manage the Beijing Olympic Games in 2008.

TETRA is used in major hotels and resorts, including the Atlantis Hotel on Palm Island in Dubai - and while on the subject of the rich and famous, perhaps one of the most glamorous uses of TETRA is by the Formula 1 Ferrari team. Sexy it may be, but this has to be one of the harshest and noisiest environments for any radio system.

Indeed, one of the key benefits of TETRA is the robustness of the codec. This codec was developed by Thomson in France and has proved to be excellent in voice quality but particularly good at working in the high ambient noise levels often encountered by our users.

Mass transit is perhaps one of the more well known applications for TETRA and the metro in Mexico is an excellent example. It is the second largest metro system in North America after the New York city subway, and serves 1.5 billion passengers in a year, placing it as the fifth highest passenger count in the world.

Airports have proved a spectacular success for TETRA. The ability to cope with high traffic demands along with dynamic grouping and a GPS positioning capability makes the technology ideal for helping to manage busy airports.

TETRA is now present in well over 100 countries of the world, but users in the US and Canada have so far been denied access to the technology. The association has been working hard trying to resolve the issues in these two countries particularly over the last 12 months.

US public safety users have already decided on their own Project25 technology. However, there is considerable interest in TETRA from other user groups including transport and the utilities.

Detailed discussions are being held with the regulators in both countries, the FCC in the US and Industry Canada. Both are receptive to seeing TETRA in their respective countries and both recognise the value to them of the improved spectrum efficiency that TETRA provides.

The first pilot system has already been delivered in Canada and discussions with other users, especially from members of the Utilities Telecom Council, are under way.

The interests of TETRA technology in Australasia are represented by the Australasian TETRA Forum, the local industry organisation that works with the TETRA Association to promote the benefits of TETRA and advance the standard and its markets.

Members of the Australasian Forum include Ansaldo STS, ComGroup, GMG Solutions, Harris, MCS Digital, Motorola, National Wireless, Panorama Antennas, Radlink Communications, RFI, Sepura, Teltronic and Zetron.

From half a dozen members in 1994, the TETRA Association has now grown to represent more than 150 organisations in 37 countries with new members coming on board all the time. The association put substantial effort into promoting the standard through conferences and exhibitions throughout the world.

The main event of each year is the TETRA World Congress and, recognising that Asia Pacific is the fastest growing region for TETRA, the next Congress will be held at the Suntec International Convention and Exhibition Centre in Singapore from 25-27 May 2010.

The association has an ongoing program of events designed to take TETRA to its markets. Our 2009 schedule included participating in and/or organising conferences and exhibitions in Australia, Brazil, Britain, Canada, Chile, China, Hungary, Germany, Italy, India, Norway, Russia, Singapore, South Africa, Turkey and the US.

Our program of events for next year will be similar and we welcome participation from industry and users at these events. Full details along with a wealth of other information is available on our website - www.tetra-association.com.

Presented by Phil Godfrey, chairman, TETRA Association - www.tetra-association.com.