London was the first to open an underground rail network in 1863, but it seems to be one of the last major routes to support cellular coverage. New York’s subway, Berlin’s U-Bahn and metros in Paris, Barcelona, Tokyo, Hong Kong, Melbourne and more all allow passengers to use their connected devices both on board trains and at station.
The lack of cellular connectivity adds to a list of issues experienced by London Tube users, including delays, cancellations, strikes and over-crowding. Transport for London’s (TfL) plan to bring 4G cellular coverage to the London Underground may therefore be the key to reclaiming the UK’s rail reputation; the olive branch of uninterrupted calls, WhatsApp messages, social media and emails, proffered to the disgruntled commuter!
4G goes Underground
TfL began tendering for service providers at the start of last year, following successful 4G trials on the Waterloo & City line during summer 2017. These included the four major operators, EE, O2, Three and Vodafone, and delivered reliable data services in both tunnels and stations.
But connecting the Tube’s least-used and shortest line is a very different proposition than delivering coverage across 402km of (mostly) subterranean Victorian-era routes, used by 1.37 billion people every year. Dark, dirty, cramped, and with trains (which reach speeds of up to 60kmph) rattling between 270 stations: taking 4G Underground will be no simple feat!
In addition to the problematic underground environment, there’s also the issue of cost – something potential partners will have to demonstrate they can manage. Delays to the UK’s Crossrail project will reportedly cause TfL revenue losses of at least £600 million, placing energy-efficiency and cost-effectiveness atop the company’s list of priorities. TfL will announce winning contractors this year, and Cobham Wireless for one will be keeping a keen eye on developments.
Connected the unconnectable
At Cobham Wireless, we understand the requirements of connecting some of the world’s most challenging environments, and the need to deliver comms solutions quickly and affordably. Cobham Wireless’ solutions have been used to deliver cellular and public safety coverage to infrastructure including the Eurasia Tunnel, the world’s first undersea road structure to link two continents; Chenani Nashri, South Asia’s longest road tunnel; metros in Dubai and Turkey, (the world’s longest fully automated metro network, and the world’s second oldest after London, respectively); as well as the China Metro, an extensive project which began in 2015 and most recently saw Cobham Wireless celebrate its 100th deployment in the country.
Plus, we’ve deployed solutions in Berlin’s U-Bahn; another historic underground rail network which carries hundreds of millions of passengers every year. Not unlike London, then!
An intelligent solution
idDAS (intelligent digital distributed antenna system) is the light at the end of the tunnel. idDAS allows for better noise management and increased throughput in comparison to analogue DAS, which for passengers, translates as clearer voice quality and an improved quality of service. This has been proven in the Berlin U-Bahn deployment, where a signal quality study noted a significant improvement compared with the legacy solution.
Data capacity can be controlled over a wide area, meaning resources can be precisely directed and shifted with ease, as well as scaled up or down depending on the requirements. This means that energy is not wasted on providing coverage for 24 hours a day to a Tube line which closes at night, for example, nor on over-delivering capacity on a line during rush-hour, which is little used by commuters.
DAS also helps to overcome those aforementioned factors which characterise the underground environment. The solution is composed of compact remote units, which can be placed track-side or at underground stations, connected via optical fibres. Leaky feeder cables then run from the remotes, providing coverage inside the tunnel itself. Overlapping coverage exists between repeaters, so if one fails, the adjacent repeater will continue to provide coverage. Dual fibre links also provide reliable back-up, ensuring uninterrupted coverage even if a cable is damaged.
A secure partnership?
Finally, security. The Underground is a key element in London’s transport infrastructure, and deploying 4G is not just a question of keeping passengers connected, but also keeping them safe. The network will support communication between the emergency services, meaning reliability and security of network equipment is crucial.
Tfl can’t afford to take shortcuts when it comes to coverage, and must pick a partner with proven credentials in public safety, and is fully accountable, transparent, and trustworthy.
Today, we expect to be able to use our phones whenever and wherever we are. In the UK, the Tube is one of the last frontiers still to be tackled, yet it’s the project which could also help turn around common perceptions of our rail industry.Back to blog list