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Similar points about the potential of TETRA data applications to improve operations are made by Stephen Northcott, senior manager at Motorola Solutions, who also highlights the importance of customer satisfaction. This is an especially important issue if the wider population is to be persuaded away from using alternative forms of transport such as cars – especially in cultures unused to mass transit services. “The user’s whole travelling experience must be enhanced”, Northcott says. “And TETRA can achieve this in a number of ways, both by collecting real time information from on-board diagnostic systems and trackside sensors and by returning real-time information to the travelling public in the form of digital displays on platforms and in carriages. Adding RFID Other wireless technologies also have a role to play here – most notably RFID, which is currently being exploited by companies like Tagmaster to automatically identify and position rolling stock even under the extreme conditions found within underground Metro systems. Already implemented on the London Underground system in a Motorola project, RFID readers are mounted underneath the train cabs to identify ID tags mounted on sleepers and enable the radio system to automatically change talk group as the train enters a new zone. In another project, this time for the overland Netherlands railway, a system using Tagmaster technology enables wheel pairs suffering from faults and flats to be identified automatically and accurately, and quickly taken out of service before further damage is done to track or train. Integration of metro TETRA systems with other communications networks and applications – most significantly those supporting public security and safety – is a recurring theme in longer term plans, and the newer distributed architectures using IP have a key role to play in enabling interconnection. TETRA – or GSM-R? Two questions, however, remain to be resolved. Firstly there is the issue of how TETRA will coexist alongside GSM-R, the version of GSM developed for the rail sector to handle voice, signalling and telemetry and currently in place in around 30 countries around the world. Debate continues to recur about the viability of GSM-R in the longer term, especially where short-haul travel is involved such as on urban commuter routes. One new TETRA functionality – Expedited Handover – is particularly relevant to both rail and metro systems because it enhances the ability of radios to hand over to a new cell quickly as the train moves along. “GSM-R specifies certain parameters for handover, essentially blocking TETRA solutions from that marketplace”, comments Cassidian’s Pesonen. “Important questions exist as to why those particular parameters have been set as they are and what their exact and continuing justification is.” Finding bandwidth The second issue – a recurring one as far as the wider, longer term future of TETRA is concerned – concerns bandwidth and the current drivers in the public security and safety sector which naturally interact with the metro market. Sébastien Sabatier, a TETRA expert at Thales, comments: “Mass transit applications – and especially train and metro applications – are mission-critical, just like public safety. In this context, it’s important to watch what’s happening in the USA with their 4G public safety project and President Obama’s call earlier this year for an investment of $7.5 billion in this area using LTE as an access technology. “We’re currently co-operating with Samsung, developing LTE and WiMAX on a TETRA core and the size of the US market alone is likely to have a huge impact on the cost and performance of solutions in other mission-critical areas – such as metro solutions.” Faced with continuous growth in passenger numbers, the Moscow Metro needed to modernize its radiocommunications to meet the demands of safety and operational efficiency. Opened in 1935, the Moscow network is the second most heavily used rapid transit system in the world. With 12 lines, 182 stations and more than 300 km of track, it carries between seven and nine million passengers each day. After investigating the available options, Moscow Metro chose TETRA as the technology which best suited its requirements for security, reliability and the flexibility to meet changing communication demands in In a project awarded to Integra Pro Co in Russia, the TetraFlex communication system from Damm Cellular Systems was chosen to provide the TETRA infrastructure. TetraFlex offers a wide range of integrated software tools, include dispatcher systems, network management tools, voice and data logging and replay facilities, as well as APIs for easy integration with third-party applications.
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