Mapping a route to 5G rail corridors
Europe’s rail networks could provide a sustainable alternative to short-haul flights, supporting the EU's goal of achieving net zero emissions by 2050. However, attracting greater passenger numbers, while maintaining competitiveness and reliability, will require a step-change in performance.
As a result, the rail industry has intensified its interest in digitization, exploring how technology can be used to improve operational efficiencies, reinforce network security, enhance customer experience and reduce costs. Barriers to success include aging infrastructure, a vast and complex array of network and a lack of funds.
One of the most promising approaches is the creation of 5G corridors – bespoke networks specifically designed to deliver reliable mobile broadband connectivity to support the creation of digital railway infrastructure.
At the heart of this activity is the Future Railway Mobile Communication System (FRMCS), an international wireless communications standard for railway communication and applications. Its implementation is reliant on 5G technology.
Lining the corridors
A number of 5G corridors are already under development including the Gigabit Innovation Track (GINT), a €6.4m research project in Germany, funded by the Federal Ministry for Digital and Transport (BMDV). It combines the expertise of Deutsche Bahn, Ericsson, O2 Telefónica and Vantage Towers to create mobile communications with gigabit data rates along one test track in the south of Mecklenburg-Vorpommern.
The 3.6 gigahertz frequencies from O2 Telefónica and the industrial spectrum used in the GINT project enable fast mobile data transmission, albeit with a shorter range than the lower frequencies currently used for 4G mobile communications, with the radio masts covering a radius of around one kilometer.
Around 20,000 new masts will be needed for FRMCS along the railway tracks throughout Germany in the coming years. They could also form the basis for high-performance mobile radio and data services for rail travelers.
Uninterrupted mobile phone coverage and greater bandwidth
Swisscom engineers made a major breakthrough on a test route between Biberlikopf and Kerenzerberg at Lake Walen with a four-kilometer antenna corridor, which achieved a 1.2 Gbit/s connection on a moving train. The long-term goal is to deliver uninterrupted mobile phone coverage along the main routes for all mobile phone users in Switzerland.
The test corridor along the railway line at Lake Walen was built in conjunction with Ericsson. A range of parameters were checked for both 4 and 5G networks, including seating position, type of train car, transmitting power and mast antennas. The 5G response time was four times shorter than 4G – an impressive 8 milliseconds.
Back in 2022 Swisscom was uncertain about the technology’s potential. It now has a solution that provides stable and reliable coverage for passengers as well as important insights for safety-relevant applications in rail transport.
Ericsson partners with ADIF for the 5G technology deployment on high-speed lines
Spanish state-owned railway infrastructure manager, Administrador de Infraestructuras Ferroviarias (ADIF), is deploying 5G network across the country’s high speed-lines with the support of Ericsson. The project aims to create the network infrastructure necessary for 5G coverage for mobile telephone operators, guaranteeing quality voice and data services across designated areas.
Ericsson’s equipment will be used along Spain’s high-speed lines, making 5G technology a critical catalyst for the on-going digitization of the economy. For rail operators its potential includes the delivery of advanced logistics services and rail operations, next generation communications, enhanced infrastructure management and maintenance, autonomous trains and a range of end-user applications.
Aligning the funding
The development and implementation of these 5G corridors will require substantial investments from the private sector as well as support from public institutions. The scale was made clear in a recent study published by the European Commission as part of its Digital Decade Policy Program. The research estimated that it will cost between €26.3bn and €78.9bn (depending on deployment scenario) to rollout 5G along 15,700 km of water ways, 106,600 km of highways and 113,000 km of railways.
Part of the solution is the Connecting Europe Facility (CEF), a European Union co-financing program managed by the European Commission. It supports the deployment of high-quality, sustainable infrastructure in the transport, energy and digital sectors by encouraging both public and private investment. It has been supporting large-scale deployment of 5G corridors since 2021, with a planned budget of around €780m.
Overall, thanks to the support of enhanced cross-border cooperation, EU Research and Innovation Funding, and most of all the substantial funding under CEF Digital, a new map of 5G corridor deployment projects is taking shape across Europe.
5G corridors for shared infrastructure
There are two ways to divide up a 5G corridor network: passive sharing and active sharing. The first involves the sharing of passive infrastructure (such as sites, towers, power supply installations and fiber transmission systems) between railways and mobile network operators. This approach increases cost efficiency by sharing the investment needed to deploy additional infrastructure. It could, in some business models, also provide an additional revenue stream for operators to cover the cost of the 5G corridor.
Since many operators may be sharing the same passive infrastructure, its ownership could vary through applying different business models. For instance, the railway infrastructure manager could play the role of neutral host, or ownership could be passed on to a tower company, which would lease capacity to the railway to establish the FRMCS coverage.
Active sharing involves the division of either active equipment (Radio Access Network) owned by one player (railway or tower company for instance) serving different Public Operators, or division of spectrum between railways and mobile operators, which can generally be implemented in two ways: multiple operator core networks (MOCN) or prioritized national roaming.
In the MOCN scenario, the operator has a separate backhaul to both its own commercial core and to the railways’ FRMCS infrastructure. Based on an agreed service level agreement, the railway is assigned an access category and prioritized bearers for its FRMCS users. Network slicing can be introduced to provide the railway with the required isolation and guaranteed resources for its mission critical services.
The national roaming scenario enables the railway user to use the operator’s 5G corridor radio access. The FRMCS traffic is routed via the operator’s core to the FRMCS core, which requires less investment as dedicated backhaul is not required from each gNodeB in the 5G corridor. However, it carries the risk of loss of connectivity in case of an operator network outage. Network slicing can be implemented for railway in the roaming scenario based on an agreed service level agreement.
Ensuring quality of experience
To realize the vision of a gigabit-connected train corridor, there are three key considerations that directly impact the quality of service and the passenger experience that need to be studied: onboard service requirements, service assurance in tunnels and station and ensured connectivity in high-speed corridors.
A clear assessment of the type of onboard services, such as passenger internet, infotainment and ticketing, as well as tracks surveillance, passenger information and announcement system, is key to any corridor deployments. The resulting service throughput will be the main design parameter but the maximum throughput along the corridor is heavily influenced by the spectrum to be used and the available channel bandwidth.
To overcome potential challenges impacting the ability to reach the target throughput per train, commercial mobile network operators (MNOs) should consider MORAN-type deployment to combine the spectrum from different MNOs. Providers could also use new lasered radio transparent windows that have 20 dB less attenuation (for 3,5 GHz) than standard windows.
Tunnels – a main component in any rail network – are another challenge. This can be overcome by the use radio and antenna systems designed to tunnel and indoor coverage. However, the main challenge for performance at high speeds is the Doppler effect, which occurs when a train is travelling at high speed towards or away from a cell. Fortunately, onboard and network-side technology can compensate for excessive Doppler shifts for trains moving at speeds up to 350Kmh.
What is clear is that all the elements are available to make 5G rail corridors a reality. The core technology, funding and vision are increasingly aligned and the benefits, including support for FRMCS, are coming to the fore.
Full steam ahead
The rail sector cannot afford delay the creation of 5G corridors. Helping the EU reach its emission reduction objectives will require a modern, well-managed and attractive rail transport network. A key factor is connectivity – with the always-on phenomena of today, customers want to be able to leave the home and step onto a train, without sacrificing any ability to work, learn, communicate, play and be entertained.
The 5G corridor infrastructure will not only enable a broad range of digital services that will bring greater comfort and flexibility for customers travelling on trains, it will also pave the way for increased automation of services to reduce costs over the coming years.
We’re excited for the journey ahead.
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