One of the biggest success stories in rail communications has been the phenomenal across-the-board deployment of the GSM-based Push-to-Talk (PTT) system that has been broadly accepted throughout the rail sector. However, as the sector transitions to 5G rail communications, it’s imperative to find the right test, validation, and active monitoring solution.

GSM-R (for “Rail”) is part of the European Rail Traffic Management System (ERTMS) standard and carries signalling information directly to the train driver, which enables communication at high train speeds and traffic density. It has become a huge success story for the industry. One of the many functionalities it brings is Push-to-Talk (PTT), which enables group calls, voice broadcast between multiple users, location-based data, and emergency calls.

PTT is a duplex system that supports group voice calls with great clarity, as only one person can speak at any given time, and is therefore viewed as a mission-critical application (MCX) from an operational, security, and safety perspective in the rail sector.

The rail sector is moving to 5G-based FRMCS

PTT is used by both “train-side” personnel (drivers, conductors), as well as “on the ground”, or “trackside”, employees such as dispatchers, shunting team members, train engineers, and station controllers, among others. For the same reasons, different PTT variants have been broadly adopted by other industries, including the emergency services, the building sector, maritime, and aviation, to name a few.

However, the rail sector is currently undergoing a communications transformation. Used for over 20 years, GSM-R will reach end-of-life status by 2030, as it’s being replaced by the Future Railway Mobile Communication System (FRMCS) – which, effectively, will skip 3G and 4G LTE and move to “5G Rail”.

Version V1 of the Functional Requirements Specifications (FRS) and System Requirements Specifications (SRS) were published in June 2023 and version V2 specifications are likely to be published by June 2024, with the aim of rolling out the technology towards the end of this year and into 2025.

Testing and validating MXC applications

It means that, as an MCX application, the new FRMCS must meet (and exceed) the exacting performance, security, and quality standards that GSM-R, and PTT, has been providing for decades. It must also enable new classes of use cases (such as autonomous trains), the IoT, predictive maintenance, and be able to handle ever-faster train speeds, at higher densities with larger volumes of data, with absolute reliability and security.

However, with an estimated 150,000km of GSM-R-supported railway lines in Europe and 250,000km of lines elsewhere in the world, the switchover will not be instant, and will no doubt need to support hybrid legacy technologies as the transformation begins.

4G LTE may need to be used, for example, as a stop-gap solution. This means that comprehensive testing and validation of the FRMCS using realistic data and scenarios – across legacy and hybrid environments in the near-term – is imperative to ensure that the network continues to meet all performance, safety, security, and operational targets.

The railway sector has unique challenges, not least the safety aspect in terms of high-velocity trains (which may in future be automated or autonomous) – mobile communications (carrying large volumes data for passengers, drivers, and operators), which must be resilient, reliable, and secure across the entire network.

So, how can MCX network providers, and operators, test and validate FRMCS before and after deployment, on a continuous basis?

Emblasoft Evolver: Functional and performance testing, and active monitoring

Such a solution needs to support functional and performance testing for pre-service updates, and new service functions, as well as enabling real-time active monitoring to continuously assure that performance, reliability, safety, and security levels are meeting expected KPIs and service quality parameters throughout the lifecycle of the service. If they are not, then the system needs to provide an alert so that any issues can be rectified before they have any impact on the users.

Essentially, a testing solution should provide all the capabilities required to test and validate pre-service and to continuously validate and assure MCX PTT, in-service and throughout its lifecycle.

Emblasoft Evolver is a comprehensive, end-to-end test and validation platform for testing and validating new services pre-launch, while incorporating active monitoring to ensure network performance, KPIs, and quality of service levels are maintained throughout the lifecycle of any service or network slice.

It can provide functional and performance testing to validate scenarios under any condition pre-launch, while network-based probes actively monitor live traffic and send real-time alerts when performance levels drop throughout the service or slice lifecycle.

Evolver can simulate and emulate millions of users and scenarios and offers a library of pre-defined test scenarios – which can also be created from scratch and reused as a new test scenario, cutting time to market and service launch schedules. It can just as easily be applied to other sectors, including ‘blue light’ organisations, for public safety at large events, aviation, maritime, construction, and more.

To find out more about how Emblasoft Evolver can help the transition to 5G Rail and support the testing, validation, and continuous monitoring of other MCX applications, download our latest paper here.