Rail
is transmitting the data aggregated by the train control
management system (TCMS) from the “millions of sensors
onboard” to allow real-time fault reporting (currently the data
is downloaded at a depot when the train is temporarily out of
service). Given the amount of power available on a passenger
train, this wouldn’t require the use of low-power wide-area
technologies, but the same wouldn’t be true for freight
wagons. Rothbaum adds that one interesting application
would be to have a location update unit, like a reliable
low-power IoT device at the end of a train. “Once you have
that in place you could then introduce ETCS Level 3 across
Europe, as one of its big challenges is determining reliably
the end of the train’s location.”
A bit of further explanation is called for here. ETCS
Level 3 supports the moving block concept – the idea that if
trains’ locations are known at all times then it is possible to
have trains running closer together without compromising
safety, thereby increasing railways’ capacity.
Myslivec’s view that a dedicated network will still be
required is supported by the current CCS TSI and shared
by the UIC’s Sarfati. Wendler highlights the difference
between public mobile network operators’ traditional besteffort
approach to providing quality of service and the ‘very
deterministic quality of service’ that the rail sector requires.
He adds that while network slicing may be able to provide
this from a resource management perspective, it doesn’t
change the coverage requirements.
The key issue here is the way that public mobile network
operators’ business model is typically concerned with
providing coverage to areas of high population density, rather
than unbroken coverage along railway corridors (train control
systems require there to be no coverage holes whatsoever).
However, Ericsson’s Rothbaum highlights the way
in which the French and German spectrum regulators
are requiring MNOs as part of their spectrum licence
obligations to provide rail passenger connectivity along the
whole rail corridor. “Now that’s not to the same level as for
critical communications,” he says, “but if they’re already
making that investment towards passenger connectivity
coverage as their licence requirements mandate, the extra
investment required to provide adequate coverage with no
coverage holes is probably small.” He also says that in two
years it is likely that many railway corridors will be covered
by MNOs’ 5G capabilities.
He adds that another problem with relying on MNOs
to provide the connectivity for critical rail communication
services is a legal one – ie, who would be criminally
responsible in the event of a communications failure that
resulted in a “life or death situation”?
Rothbaum also points out that given the EU’s goal is to
retain the harmonisation we have today (ie, a train with
GSM-R can travel across Europe with no issues), if MNOs
are to provide this service, they would need to be using the
same dedicated band of spectrum to do so.
There are other issues that may arise were MNOs to be
used by train operators in the context of FRMCS, according
to ECC Report 294 – Assessment of the spectrum needs for
future railway communications. These include whether it
would require certification of the MNO’s software updates
and its implementation of new 3GPP releases, prior to them
being deployed on the live network, which “could have a
major impact on MNO evolutions and operations”, along
with concerns over MNO lock-in, given the investments
that an MNO would have to make (and which would
have to be made again when switching to another MNO),
together with the need for a “stable long-term relationship”
between the train operator and the MNO – which creates
risk given that the MNO could be bought by one of
its competitors. The report adds that “when an MNO
is acquired by another one, the new entity inherits the
previous commitments. But a risk exists that services are
terminated and existing contracts are not prolonged.”
Of course, it is not only Europe that is looking to
embrace 3GPP technology for railway use. Rothbaum
highlights Indian Railways’ request for proposals (RFP) for
ECTS over LTE as a sign of its confidence in the technology,
and adds that signalling vendors are developing ECTS
products that will work over LTE in order to respond to
the RFP.
In addition, Frequentis is delivering end-to-end 3GPPcompliant
mission-critical communications over a private
LTE network, using a public network as a fallback, for a
major transport operator in the Asia Pacific region. This
includes the user working positions and key technology
applications such as mission-critical push-to-talk (MCPTT).
“We’re delivering all the mobile apps, the SDKs for the
cab radios, all the application servers, the security measures
for the applications, the dispatch system, the voice and
messaging recording, the integration with the legacy system,
and GIS integration,” says Myslivec.
We have seen that FRMCS has a lot to offer the railway
community, its development is aiding the wider missioncritical
communication sector, and the work to iron out
the practicalities around the migration from GSM-R is
gathering a head of steam. Given MNOs’ enthusiasm to
serve many different industries, as opposed to just
consumer and generic business communications, it will be
interesting to see if this, coupled with networking slicing
and other innovative techniques, can overcome some of the
challenges around the use of public networks for missioncritical
use. While the public safety world is coming to
terms with using MNOs for mission-critical broadband,
control of objects weighing hundreds, if not thousands,
of tonnes may require even more confidence on the part of
train operators.
Over in Asia, train
operators are also
turning to mobile
broadband
20 www.criticalcomms.com October 2019
/www.criticalcomms.com