Cobham Wireless launched a new mobile tester for railway GSM-R communications systems at PMRExpo in Cologne, Germany (24-26 November 2015). Safety considerations are of major importance to railway network operators, so testing of their communications systems is vital.
The new Cobham Wireless 2201R is designed to connect directly to GSM-R device types including high-powered Class 2 radios, and is a replacement for the previous-generation 4202R tester. It enables railway operators and suppliers of GSM-R radios and modems to validate the correct operation of GSM-R radios, both in the laboratory and in the field.
The tester features an easy-to-use interface and it provides fast and accurate RF measurements and a full range of features including voice, data and SMS testing. The tester has handles at each corner, and the battery is conveniently located on the rear panel so that it can be unclipped for easy field replacement
Featuring optional battery operation with up to 2.5 hours life, the 2201R has a compact form-factor and is light weight—just 6.2 kg including the battery, thereby making it easy to perform full testing of the radio within the confines of a locomotive cab.
Comprehensive GSM-R validation
Speaking to Wireless at PMRExpo, David Asquith, product manager at Cobham Wireless, said. ‘The 2201R provides the test engineer with everything that is needed for comprehensive GSM-R validation.’
He explained that along each railway line is a series of GSM-R base stations, which enable the driver to communicate. ‘Essentially we test the validation of the functionality of the GSM-R radios in-cab, in the control room and handheld terminals,’ said Asquith.
‘You can pick the tester up by the handles, so it is very portable and it runs on battery power. Typically, what we do is set up with, for example, a cab radio, as we have in our demonstration at PMRExpo.’
The radio can do basic GSM calls and Edge (which is also part of GSM-R set up) and GSM-R of course. It can support group call testing, emergency call function testing and SMS, so you can send texts and test that aspect. Call types include: point-to-point call; voice group call system, featuring push-to-talk; voice broadcast system; railways emergency call; and shunting emergency call.
Three types of test mode
Asquith explained that the 2201R can be used in three different modes: manual, autotest and remote control. ‘With the manual mode you use front panel controls to set up the call, make the call and take the measurements.
‘The Autotest mode allows you to create a test script using Lector on a PC. Lector is a software programme we use to control the tester remotely. It’s a management tool with a wide ranging software that interfaces with all our test products.
‘You load the test-script into the tester and push one button to start the test, which it will then run through it. What this allows you to do is take the tester from radio to radio and test them all in the same way. You then load up the measurements you’ve taken back at the depot.
‘Or you can run tests under remote control using the 7310 Lector and Scriptor product family, where test scripts may be created, modified and run,’ said Asquith, who added that any test scripts created for the previous-generation 4202R tester model can be run on the new model.
2201R features and benefits
The 2201R features the simulation of group calls (VGCS) at various priority levels—including emergency calls—to verify the performance of not the only cab and mobile radios but also peripherals such as optical and acoustical alarms. These tests ensure proper performance of the overall radio system and help to verify that safety functions will work in an emergency.
The 2201R also allows voice group calls to and from the mobile to validate bi-directional communication. For the mobile originated call, the tester decodes the group ID and priority level while performing measurements.
The short message service (SMS) function in the 2201R takes testing further by focusing on retrieving all the necessary parameters used by the phone for transferring messages that will help the technician to analyse faulty behaviour.
GSM-R operates in the same bands as GSM: 900 MHz and 1800 MHz and replaces earlier analogue VHF railway communication systems. Although the GSM-R specification was finalised in 2000 and some European networks began deployment from 2006 onwards, networks are still being extended and continue to be rolled out.
‘The biggest regions outside of Europe are China, which is a key Cobham customer, as is India. GSM-R is also used in Australia, although it uses a different band to Europe – the DCS 1800 MHz band, as opposed to the most commonly used GSM 900 MHz band,’ said Asquith.
‘There is still a lot of GSM-R going in now,’ he continues. ‘Poland and Greece are new markets, for example. Finland is an odd exception in Europe in that it found it was cheaper to re-purpose its rail communications using the TETRA radio standard.’
Asquith pointed out that one thing GSM-R does suffer from is interference from commercial mobile networks and that will be a key driver of any replacement technology, because where safety is of paramount importance you don’t want interference affecting an emergency call.
The 2201R Mobile Tester is available now, and includes GSM, GSM-R, Autotest and GSM-R test USIM card, with options for GPRS and EDGE plus an assortment of accessories.