Why TETRA for the European urban public transport market?
Why is TETRA chosen for communications across urban public transport markets? This article takes a look at the reasons behind the technology choice for the bus, tram and metro sectors.
TETRA – the choice for urban transport market communications
The European Telecommunications Standards Institute (ETSI)’s digital trunked radio standard, TETRA (Terrestrial Trunked Radio) is today the most widely used open standard in its field in the world. TETRA’s major strength is the provision of highly resilient, functionally-rich mission-critical voice and data for public safety, public transportation (including heavy railways, light-rail, metros, trams, buses, seaports and airports), utilities, oil & gas, industry, and an increasing number of other sectors looking for the best critical communications available.
The global TETRA market has grown exponentially year on year since the technology’s early successes in Europe. A large number of equipment manufacturers and specialised solutions providers were attracted by the huge potential of the TETRA market. They created a vibrant ecosystem and made TETRA the de facto radio technology for the many markets that it serves today. For example, TETRA has allowed governments around the world to implement large-scale, nation- and region-wide shared public safety systems which provide enormous benefits to their societies. Regarding the transport sector, the majority of urban transport operators today will specify TETRA as best meeting its operational, safety and security requirements. In fact, although largescale public safety projects drove TETRA’s early applications development, the transportation sector has now overtaken the public safety market in terms of the number of individual networks deployed around the world. The transportation industry is playing a key role in this new reality as the list of successes grows. Just a few examples of successfully deployed TETRA networks in Europe alone include:
- London Underground
- Madrid Metro
- BKV – Budapest Public Transport
- Several light railways in Spain (Alicante, Tenerife, Parla)
- Movia Public Transport, Denmark
- STIB/MIVB – the Brussels public transport company
- BVG – Berlin Transport Services
- Värmlandstrafik, the public transport organisation for the Värmland region in western Sweden.
Why TETRA has been adopted for transport operations
In looking at any new or replacement radio communications network, today’s transport operators need to consider a fully operational end-to-end system, with easy integration and secure features. Any communications system deployed on a transport system has to be reliable: failure to route buses or control trains can be catastrophic, not just to the transport operators but to the country, town or city economy. The need for secure, reliable, featurerich communications is therefore paramount. Any solution has to work, and it has to work 24/7/365. The reliability, availability, security and interoperability functions offered by TETRA are key reasons why TETRA is chosen. The added benefit of TETRA interoperability in the event of a major incident means that public safety agencies such as police, fire and ambulance services can instantly communicate with transport staff.
TETRA offers a complete, totally secure, resilient, service-rich communications solution for the full range of professional user groups across both private and service provider-based operations. Predominantly IP-based infra - structure, a wide range of fixed units, mobile and hand-held devices (with integrated GPS), radio modems, dispatch facilities, large and smaller-scale control centre functionality and hundreds of applications tailored to specific industry segments provide a rich, futureproof PMR communications environment for increasingly demanding, security-conscious customers. TETRA also integrates seamlessly with other existing and emerging IT and communications technologies to create a total communications solution.
In developing the TETRA standard to meet the needs of traditional PMR user organisations, numerous services and facilities have been provided that clearly differentiate TETRA from other wireless technologies. These include:
Voice Group calls; individual calls; emergency call (pre-emptive priority call); priority calling; busy queuing; Dynamic Group Number Assignment (DGNA); ambience listening; area selection; late entry; authentication; air interface & end-to-end encryption; direct mode operation (DMO); and terminal disable.
Data Status messages; Short Data Service (SDS); circuit mode data; Packet Data Service (PDS); multi-slot packet data; and TETRA Enhanced Data Service (TEDS).
Services such as group calling, direct mode operation (DMO), packet data services and TETRA Enhanced Data Service (TEDS) are all integral to the TETRA standard, having been seamlessly designed into the system core.
TETRA and wider integration with data systems
The requirements for data across transport operations have grown, but whilst some say that TETRA’s data capability is limited, transport operators have found that it is ideal for meeting their needs for machine-to-machine communi - cations systems and telemetry. That is not to say that designing these critical communications systems is as easy as it sounds. From bus, tram and train fixed mobiles through to handhelds, voice and data, passenger information systems, telemetry and signalling, all modes of transport status information and alarm information is needed. All this functionality contributes to a very complex set of requirements for the TETRA communications system. Reliability and security is therefore essential for communi - cations in this environment.
The multi-functionality voice and data capability of TETRA is ideal for urban transport applications. Operations require high levels of safety and security for passengers, vehicles, rolling stock and staff. Information delivery to passengers and staff is vital for timetables, passenger safety, operational and maintenance staff, and telemetry from and to the trains themselves. The trains, trams and buses have sophisticated control and monitoring systems derived from on-board computers interfaced to the TETRA comm - unications system.
A large number of transit operators are considering TETRA for safety-critical signalling applications. This has been a subject of research by the TCCA Transportation Group, with the result that ETCS (European Train Control System) compliant signalling is now implemented over the TETRA system.
Urban transport operators that have adopted TETRA have found that it is able to provide seamless and secure operations, ensuring smooth, reliable and efficient services both in operational and passenger areas. TETRA has proven that it is able to provide transport operators with all of the following:
- Comprehensive, inherent, built-in PMR (private mobile radio) functionality which is essential for railway operation
- Direct Mode Operation, for direct comm - unications outside the main radio network, essential for operations such as shunting
- Fast and consistent voice call set-up even over wide area connections ● Flexibility in choice of frequency bands, especially in UHF – e.g. 350-370, 380-400, 410-430 and 450-470 MHz bands
- Improved spectrum efficiency (four times more channels for communications using an equivalent amount of spectrum) and reduced bandwidth requirements compared with 200kHz GSM-R channels
- Operation at the lower end of UHF band – resulting in better coverage and leading to fewer base stations to cover the same length of railway
- High-speed packet data services (multi-slot packet data and TEDS) for mission-critical and safety critical applications support
- Multi-vendor support and competition for the core system, subscriber radios and peripherals.
Robin Davis is the Chairman of the TCCA Transportation Group and a Project Director and Management Consultant at Actica Consulting based in the UK. Initially qualifying as a railway signalling engineer, Robin went on to advise various government organisa - tions around the world on the specification, procurement and delivery of advanced ICT technology, mission critical control room applications and TETRA. Specific to transpor - tation, Robin has advised various transportation companies on the procurement of digital radio systems, notable projects include the Malaysia Express Rail Link, one of the first TETRA systems operational in the region, and Taiwan High-Speed rail. In the UK Robin has advised various transport operators, the Highways Agency, London Underground and Transport for London.
