SWITZERLAND: Ericsson and Swiss national operator SBB are on the brink of completing what they say is Europe’s first live integration of GSM-R with an advanced IP Multimedia Subsystem platform featuring Voice over LTE functionality.
The work to modernise SBB’s telecoms infrastructure covers 3 100 km of the national network, and was required because telecoms company Swisscom is planning to decommission its 3G services by the end of 2025.
Voice roaming for Swiss rail operations has for several years relied on Swisscom’s public 3G network in areas where GSM-R coverage was not available. With Swisscom’s decision to decommission its 3G services, Swiss rail operators faced a choice of whether to further upgrade the legacy GSM-R network to provide more coverage. However, SBB agreed a contract with Ericsson to deliver IMS and VoLTE, bridging GSM-R’s rail specific functions with modern mobile and fixed telephony systems.
Ericsson says it has integrated multiple vendor technologies into a converged IMS Core. This ensures continuous end-to-end rail communication, while the deployment strategy prioritised zero service interruptions and robust safety compliance. Key features of the implementation included IMS-GSM-R interworking, GSM-R numbering adaptation and mandatory safety-critical functions like emergency stop calls. Starting in June 2023, the IMS/VoLTE integration progressed through rigorous testing phases that culminated in the new telecoms architecture going live in April.
With the Swisscom switch-off approaching, Ericsson says the infrastructure is now fully operational across approximately 450 trains and 1 000 operational devices using VoLTE technology. Full migration of train fleet communications and smartphone operations is expected before the December 2025 target completion date.
The telecoms supplier says its live IMS/VoLTE platform offers scalable, modern dispatcher telephony, with key rail-specific functions — including European Integrated Radio Enhanced Network functional numbering, emergency stop calls, group calls, and onboard announcements all being maintained during the transition.
The switchover also helps SBB to prepare for future 5G-based Future Railway Mobile Communication System innovations. ‘Our work with SBB demonstrates our capability to deliver complex digital transformations under tight timelines. We look forward to setting benchmarks in railway communication innovation and supporting the transition to FRMCS in the coming years’, says Nicolas Segond, Head of Mission Critical Communications for Railways in Europe, Middle East & Africa at Ericsson.
