What do these metro companies have in common: Shenzhen Metro in China, RATP Paris in France, Malaga Metro in Spain, and BVG Berlin Metro in Germany? And how is the Helsinki metro the same with a difference?
They all have three vital needs for professional communications, but these companies have something else in common as well.
They all use a TETRA system for their professional communications.
Case: Shenzhen Metro network
Shenzhen Metro network is the first city in China where all TETRA radio communication systems from all metro lines are interconnected. Shenzhen has 5 metro lines operational, spanning around 178 km. Every day, the metro lines serve around 2 million passengers.
Metro staff in Shenzhen enjoy seamless roaming and TETRA communications services along all metro lines. For them, there is no longer a boundary between metro lines. With the benefits from the interconnected TETRA network, Shenzhen metro has achieved a united, safe and efficient operation.
Case: RATP Paris
RATP completes around 3 billion customer journeys a year. In addition to running metro trains, RATP also operates buses, tramways and mass rapid transit for Paris, as well as an automatic shuttle service that connects the Paris Orly airport to the capital.
RATP’s public transportation network is one of the densest in the world, serving 11 million residents concentrated in a 12,000 square-kilometre area.
To support 1,000 trains, 300 stations and 4,500 buses, RATP has a large team of engineering and maintenance personnel, as well as its own 1,000 strong security department. Add in drivers, ticketing and station staff and that’s a lot of people who need constant, reliable communications to ensure the transport network runs smoothly.
RATP employees rely on a fully integrated TETRA network from Airbus. They use talk groups that let staff from all areas of the system communicate when needed, both for routine jobs and in an emergency.
Case: Berlin metro
Berliner Verkehrsbetriebe (BVG) is the leading municipal public transport company in Germany. Special indoor location solution has been integrated into their TETRA network.
Case: Malaga Metro
Malaga on the Costa del Sol is one of the most popular tourist destinations in Spain. Metro Málaga runs two lines, one in the city and one along the coast and opened in the summer of 2014. The metro network uses a Claricor TETRA system for its radio communications.
Case: Helsinki metro
Helsinki metro has this in common with the four others: it also uses a TETRA system. There's a difference, though: this metro company has adopted the use of Finland’s nationwide public safety network, Virve.
Helsinki metro made the switch to digital radio to improve internal communications, but it was also seen as a way to enable closer cooperation with other Virve users, such as the police and rescue services. Get the details from this article: "Virve helps Helsinki keep the wheels turning"
The three vital needs for radio communications
Any metro company needs a reliable, stable and flexible communication system with rich applications. TETRA technology can satisfy the three vital needs of metro communications:
- Keeping in touch. Drivers are on the move and change cells frequently. They may work on a different train every day and even switch trains during a shift.
- Excellent coverage. For metros, radio coverage is needed in tunnels, which limit the propagation of radio waves.
- Reliable contact. Whether trains run on the ground or under it (or both), public safety demands instant, reliable, two-way communication between drivers and dispatchers, stations and security personnel.
How best to keep in touch over radio?
1. Seamless call handovers are a must. The system and the radio terminal both need to use Type 1 Handover, ensuring connections continue unbroken, even when users move between cells.
2. When the driver of a particular train needs to be reached, it is important that either the train number or the train line number can be used. It is also essential to reach the driver of the train even if the person changes as people change shifts.
3. Role-based numbering ensures that the correct driver can be reached using the train/line number even when the driver uses a handheld radio.
Three ways to ensure excellent coverage
1. When building radio coverage, the trick is to balance the uplink - traffic from a radio terminal to the base station - and downlink - from a base station to the radio terminal. The uplink is far more critical, so a base station should have signifi cantly better than average uplink connection. The better coverage with fewer base stations helps cut costs.
2. Setting up a network in difficult locations such as tunnels can be challenging. Sensitive, powerful base stations with low power consumption and small physical size are important. It must also be possible to operate and maintain them remotely.
3. While regular RF repeaters are an option for tunnels, a miniature base station can be so much better. For example, you can set one TB3p base station up on a metro station to provide coverage in two directions into the metro tunnels.
How to ensure reliable contact
1. Instant connections are essential in the fast-moving rail environment. TETRA group calls save time, and the best TETRA systems can connect a group call in less than half a second.
2. Free mobility within the network is also important for the users. They need to be able to move anywhere within the network, yet use the same services in the same way.
3. Another must is priority scanning. Normal scanning allows the radio users to monitor their own talk groups. Priority scanning means that talk groups each have a priority that is specific to an organisation. A radio can scan two or more talk groups while it is engaged in a call. When a higher priority call starts, the radio may leave a current call to join this new call.
A metro company of any size will be well served by a TETRA system. TETRA is truly mission-critical technology and it has been developed to meet the needs of demanding professionals. TETRA systems from Airbus do meet the three vital needs - and much more.
There are five things to consider when investing in radio communications. Download this free guide: it will help you make an informed decision:
Airbus / Secure Land Communications has delivered TETRA radio coverage to more than 70 metro lines around the world.