The link between the fast-moving train and the broader fixed trackside
infrastructure has always been one of the key components of a train communications network. A major rail operator in Japan sought to build a trackside
infrastructure that will offer a corridor of wireless coverage on and around the track.
This would give the wireless clients on the train constant high-speed connectivity
to support applications both onboard and along the rail line. There are numerous
issues to face before this network is ready to tackle challenging CBTC operations:
seamless roaming is needed to provide uninterrupted communications,
and EMI/EMC compliance is critical to ensure that there is no system performance
degradation due to harsh wayside operating conditions.
Application Requirements
• Constant high-speed connectivity along the track
• Optimized AP coverage along a 20 km route
• Seamless roaming between trackside APs
• Open standards secure future upgrade path
• Compliant with rolling stock and trackside standards
System Description
In this application, the backhaul network needed to be powerful enough to support
communications between the on-train data network and the track-side fiber network.
The trackside infrastructure consisted of ten stations placed along a 20 km route.
Multiple AWK-6222s outdoor dual RF access points were deployed at 200 to 400 m
intervals on poles. The data from each AWK-6222 is routed to different operational
control sites via a fiber network connection, which was formed with two IMC-101
media converters. This provides each AP with fast and reliable connection to the
wired backbone.
Onboard the train, a AWK-5222 dual RF client was installed in the front and rear
carriage to support the passenger information system and provide control and
monitoring links with the trackside network. Moxa's fast Turbo Roaming technology
and redundant RF mode secure the train-to-trackside communications link.
With Turbo Roaming technology, the onboard clients are agile enough to keep up
with the fast-moving train and can seamlessly maintain a connection with the
trackside network. What's more, Moxa's AWK series products have undergone
extensive vibration, shock, and EMC testing to confirm their resilience in demanding
railway environments.
Moxa Solutions
• Continuous WLAN coverage along the track
• Wireless roaming with fast handoff in redundant
RF mode
• Support high-speed data links up to 120 km/h
for trains
• Media converters form fiber optic backhaul
networks to interconnect APs
• Outdoor rated and extended operating
temperature
• EN50155 for rolling stock and EN50121 for
trackside applications
