Applying TETRA at your airport

TETRA is more than just a digital radio communications system. A growing number of airport users are discovering that the rich feature set of TETRA and its broad range of data services can be used to improve the efficiency of daily tasks and workflows.

This is important because the total number of flight passengers is increasing every year, but the number of airports is not; existing airports therefore need to improve their efficiency to handle more and more passengers. TETRA applications help to improve the efficiency at airports.

In the first months after the roll-out of a new radio communication system it is mostly used as a replacement for the old analogue system, utilising mainly voice services like group calls and individual point-to-point calls. Airport communication is mission critical for the airport organisations and therefore extra care has to be taken during the migration phase. An additional source of uncertainty can be avoided by replacing in the first project phase only the services which are known to the users from their old system. After the users are accustomed to their new radios, the next project phases introduce new services and new applications. This is a natural evolution we see very often when an organisation starts using a digital radio system.

TETRA is an open standard from ETSI, the European Telecommunications Standards Institute. It was specifically developed for professional mobile radio users and is now used in more than 85 countries worldwide. TETRA is employ by a broad range of both large and small organisations. The big nation-wide public safety networks are using it as well as professional users in smaller on-site networks. The transportation sector, which includes metros, public transport trams, buses and airports, is one of the fastest growing sectors in TETRA. As a true, multi-vendor open standard, TETRA is the preferred choice for airports.

Airports are a very complex environment for communications. Radio communications at major airports may be compared to a big event like the Olympic Games. They have to be available 24 hours, 7 days a week and 365 days a year. There are no other facilities worldwide, requiring so many subscribers on such a limited geographical area, coupled with such a huge quantity of calls. In addition, a typical major airport will have in the region of 30-40 km of in-building coverage systems providing radio coverage to all areas of the airport, including underground car parks, baggage and cargo facilities and aircraft repair hangars.

Mission critical and safety critical communications have to be handled by the radio system. Users like security personnel, the fire department and the people working on the apron need reliable and dependable communications because it can save lives. For other organisations like ramp agents, airline personnel, the fuelling, baggage handling, catering and cleaning teams and many others, radio communication is critical in fulfilling their daily work on time.

What are the typical applications for airports and what are their benefits?

One application that is a big improvement in airport communications is the dynamic assignment of talk groups, sometimes referred to as Object Call or Flight Oriented Dialling. For each flight at the airport a dedicated talk group is created in real-time, which includes all the relevant people necessary to handle the flight on the ground and to prepare it for take-off. In most cases the flight number, e.g. “AF241,” is used as the name of the talk group. This talk group assignment can be done semi-automatically, i.e. each radio user requests his inclusion into the talk group for a specific flight according to his daily schedule by sending a short data message to the airport management system when he is ready for the next task. The user is then included into the talk group. Alternatively, the assignment of the talk group is done automatically via the AODB (airport operational data base). The database triggers the creation of the dynamic talk groups and all users responsible for that flight are automatically included in the talk group for a specific flight. In case the flight is delayed or the arrival gate is changed, all radio users are notified about the changes with a text message.

According to Etelm, the supplier of the TETRA System for Air France at Roissy Charles de Gaulle Airport, the dynamic talk group assignment is the main feature of the system. This 12 site system, operational since 2005, handles 2000 radio users and 16000 calls per day; half of them are group calls, the other half are individual calls. Status messages are another important feature. Each state change of a flight is reported via the radio system with a short status message. Sending of pre-defined status messages is very quick and often requires only one or two key hits on the radio.

Integration of TETRA with other communication systems may help to simplify procedures. By dialling a specific number, radio users can, for example, access the public announce system in the terminal building to broadcast important information to the passengers.

On the other hand, the automatic broadcast channels which are used for airport information or weather information can be through-connected to TETRA talk groups. Each authorised TETRA radio user may switch to Page 3 of one of those talk group channels to listen to the announcements. There is no limit on the number of TETRA channels which can be used for broadcasting information because TETRA utilises radio resources very efficiently.

For the air traffic controllers in the tower it is important to be able to communicate with the people on the apron. Connecting the TETRA system with the air traffic communication system allows the air traffic controller to speak into the TETRA talk groups used by the apron people. In case of an emergency, the air traffic controllers can warn and instruct people on the apron very fast.

TETRA systems are also integrated with airport IT systems. Air IT, the network operator at Hannover airport, uses a Rohde & Schwarz TETRA System with Sepura terminals. With the help of an application the efficiency of the de-icing procedure is improved. In the past, the scheduling of the planes for the de-icing procedure was done by voice communication between the tower, the pilots and the de-icing teams. After de-icing, a plane has to takeoff within a certain time. If this time is exceeded the de-icing has to be started again, thus delaying the take-off. Therefore, an efficient communication is crucial to minimise delays. The integration of the flight information system, together with the usage of short data messages instead of voice communication, has improved the de-icing procedure. The dispatcher takes the order of the queued planes for take-off from the flight information system and schedules the de-icing teams accordingly. The de-icing personnel receive instructions for the next plane on their radios via a short text message. An acknowledgement is sent back at the start and at the end of the de-icing. This data is used to trigger an alarm to the tower in case the plane will exceed the available time until take-off after de-icing. This application also allows logging of the data for the creation of reports, statistics and invoicing.

Integration of airport communications systems with the various IT systems is becoming more and more important. Closer integration can improve the efficiency of work flows and will enable Collaborative Decision Making. EADS Secure Networks, one of the major suppliers of TETRA systems, and SITA, a leading service provider of IT business solutions and communications services to the air transport industry, have recently announced plans to work together to provide integrated solutions for airports.

There are many fields where system integration and applications can improve performance, such as surveillance systems, biometric access systems and RFID systems. Secure, RFID-based entry systems allowing drivers to authenticate, automatically open the entry door and enter the facility without leaving the car, bus disposition systems and applications for the support of the fuelling teams are in operation at many airports.

The deployment of Wi-Fi systems on airports might indicate that those systems are used for all data applications. Wi-Fi systems can provide high data rates but usually do not cover all geographical areas at an airport. Mission and safety critical data applications are using the digital radio communication system instead of the Wi-Fi system.

Not only major airports are deploying TETRA systems. An increasing number of airports like Birmingham, Salzburg, Frankfurt Hahn, Granada, Seville and Ibiza are migrating to a digital radio system as well. In many cases, their old analogue radio systems have reached the end of their lifetime. Spare parts and maintenance support is often not available any more. With the change to digital often comes a change in the way that the radio system is operated. Analogue radio systems are traditionally purchased and operated by the airport authorities. With digital systems, many airports decide to buy a service from an operator rather than the system. Because of the success of TETRA they have a wider range of radio products to choose from.

Interoperability amongst the equipment of different suppliers was key for the success of TETRA as a multi-vendor standard. The TETRA MoU Association has established the TETRA interoperability process and is currently extending the testing and certification activities beyond Europe to other parts of the world. Especially in Asia, we see a number of new manufacturers launching their TETRA products. This will further stimulate competition and innovation, which is for the benefit of both the operators and users. I am sure that we will see many more airports joining the TETRA community in the future.

Harald Ludwig

Harald Ludwig has more than ten years of experience in the professional mobile radio industry and worked several years for a company developing safety-critical communication systems. In 2006, he was appointed chairman of the TETRA MoU Association Technical Forum, which is responsible for the technical interoperability of TETRA systems and terminals.