The Technology

Satellite x Cellular Antennas: High-Capacity Aggregated Connectivity

The GZ-30 trial provided a means of demonstrating the viability of Low Earth Orbit (LEO) satellite constellations to reach gigabit connectivity on high-speed rail vehicles.

Icomera and Deutsche Bahn installed 2 Starlink satellite antenna tiles onto the vehicle and seamlessly aggregated satellite and cellular communication links using its SureWAN™ algorithm, supporting the hardware using its ICONIC network monitoring software suite.

Starlink “Tile” antenna on the roof of the Advanced Train Lab (left), A flat high-Performance satellite antenna in an enclosure on the roof of the Advanced Train Lab, pictured in the background (right).

Low Earth Orbit Satellite Connectivity: The Sky’s (No Longer) the Limit

As an authorised reseller of Starlink for rail, Icomera demonstrated how its satellite connectivity solution for trains can enhance transport operators’ digital strategies by integrating high-throughput, low-latency satellite Internet connectivity with its robust onboard network platform.

Sectorised Antennas

Omni-directional antennas have historically been a mainstay for public transport connectivity solutions due to their simplicity and broad coverage. However, their all-encompassing design often yields interference, reduced signal quality, and limited throughput, particularly when multiple frequency bands or networks vie for bandwidth at the same time.

For the trial, Icomera deployed sectorised antenna technology, which resolve these challenges by dividing the coverage area into discrete segments or “sectors,” each optimised to track signals from a particular direction or frequency band.

Icomera X7: Scalable, Future-Proof Connectivity for Rail

At the heart of the Gigabit Zug network was the X7: Icomera’s flagship high-performance mobile connectivity and applications hosting platform, purpose-built for public transport. It unifies future-proof aggregated connectivity, secure virtualised application hosting, and robust built-in storage to satisfy even the most demanding requirements.

Two Icomera A2 Wi-Fi 7 Access Points on board the DB advanced TrainLab delivered maximum wireless capacity to onboard smart devices.

The onboard gateway utilised SureWAN™, Icomera’s industry-leading connectivity technology protocol for combining multiple networks (cellular, satellite, trackside) in parallel, providing the fastest, most reliable connection available for onboard systems.

Wi-Fi 7 Access Points: Harnessing the Latest Wireless Standard

An onboard network is only as powerful as its weakest point. Icomera’s A2 Wi-Fi 7 Access Points enhance stability and prevent bottlenecks using wider channels and multi-link technology, while leveraging Wi-Fi 7 (the latest standard in wireless connectivity), ensuring that connected onboard devices receive maximum throughput, even in congested conditions.

• Higher Data Rates: Wi-Fi 7’s improved channel bandwidth (up to 320 MHz) enables gigabit data throughput on each AP.

• Reduced Congestion: Multi-link capabilities help distribute traffic more effectively, so that real-time services (video calls, conferencing) experience minimal jitter or delay.

• Optimised Performance: Advanced modulation techniques, such as 4K-QAM, further improve spectral efficiency, ensuring that each connection is utilised to its maximum potential.

The Implications for Public Transport

Filling in the Not-Spots

While terrestrial networks are comparatively well-developed throughout Germany, in most cases, train routes pass through large swathes of rural terrain where cellular coverage and capacity along the track may be inconsistent or entirely absent.

In the case of the GZ-30 test, Starlink connectivity was used to fill in regions with sparse cellular availability, however in most other cases, LEO satellites can be used as a primary source of connectivity for the majority of routes, with terrestrial networks taking over when satellite availability drops, particularly in regions like the Arctic Circle where Starlink has lower comparative availability.

Therefore, by aggregating Starlink for rail with other networks, operators can deliver seamless passenger Wi-Fi and operational connectivity, even in the most remote and challenging environments.

The Gigabit Train: A Present-Day Reality

The GZ-30 trial demonstrated that a ‘Gigabit Train’ can become a reality within weeks, rather than years, underscoring the benefits of aggregating multiple technologies to address the challenges of modern rail. The ability to combine disparate sources of connectivity in real-time, even uncorrelated terrestrial and satellite networks, provides a powerful blueprint for digital trains of the future, even far beyond 2030.