In today’s world, public transportation, whether high-speed trains, subways or other commuting options, no longer simply face just the task of transporting passengers from point A to point B. Further considerations beyond vehicle operations apply, including public safety as well as passenger’s experience. In the US, most of commuters spend an average of at least one hour a day commuting to and from work.
In Europe, the average stands at 45 minutes and in Asia, the average is even longer. With time being a valuable resource, a commuter’s time on mass transportation is a valuable commodity. In today’s fast paced world, most passengers cannot afford to tune out for such a long periods of time. Passengers utilize this time to unwind, catch up on work or news, listen to music and more, creating a greater demand for wireless solutions in mass transportation.
There are a number of technologies that provide multiple solutions for public transportation broadband wireless. Each technology has its value and limitations. Wireless broadband solutions have multiple functions on trains, metros and buses: the basic, critical function of command, control and operation of the transport; public safety via in-cart video that transmits all onboard activity back to HQ, as well as info regarding driver and passenger experience. We must also keep in mind that the greater the distance and speed covered by the transport, the greater the challenge of providing a reliable broadband wireless solution.
Vehicle-to-ground communication is mostly conducted by radio, which is mostly voice and analog. To overcome this gap between analog radio communications and the current demand for wireless broadband, operators usually deploy several radios, each with a different purpose
Fast handoff requirement for transmitting onboard information back to HQ poses another great challenge for broadband wireless communications. Average handoff time takes a few seconds, however, for instance a high-speed train has less than a second for handoff.
Vehicle -to-ground communications in urban and N-LOS areas poses yet another challenge. In most cases, Professional Mobile Radio (PMR or Private Mobile Radio) combined with TETRA is used. This mostly delivers the demand for voice communications, command and control, but offers very limited bandwidth and a UHF spectrum that is often congested by other users.
To overcome the above challenges, more and more mass transit operators seek LTE based broadband wireless solutions. LTE is basically the global 4G wireless standardization. It provides high performance, fast handoff, high bandwidth, greater coverage, flexibility and easy deployment, and is also embraced by most communications solution providers.
Communication Systems for Railways
The number of applications in the railway environment that could benefit from having a reliable radio data carrier service keeps growing – from train diagnostics, to remote condition monitoring, on-board customer information displays, public announcements, passenger help points connected to centralized helpdesks. Many of these applications are actually not very demanding in terms of bandwidth. Diagnostics and remote condition monitoring typically send even less data than modern train control systems, and with less demanding delay requirements. GSM-R and GPRS are perfectly suited to cater for these applications.
However, as ubiquitous data transmission becomes more and more pervasive in our society, there is an ever-increasing pressure for railway infrastructure managers to provide a number of high bandwidth applications. The most obvious example is the transmission of real time streaming video for both on-board security CCTV and Driver Assisted Video Systems (DAVS) for Driver Only Operation (DOO). GSM-R, even if augmented with packet switching GPRS or EDGE modules, does not provide a data rate that can support real time video streaming.
The GSM-R Industry Group has made a public commitment to support GSM-R at least until 2025, and that commitment has been extended to 2028 during the UIC GSM-R Conference in Paris last September. However, there is still a level of uncertainty about what will happen after those dates. The UIC is currently conducting a study to identify a suitable candidate to be the successor technology for GSM-R, with a very clear front-runner: LTE.
Therefore, in terms of longevity, it is obvious that LTE will still be around years after the last GSM-R base station is decommissioned. As for bandwidth limitations of GSM-R/GPRS, bandwidth is what LTE is all about.
Why LTE for Railways
GSM-R supporters sometimes claim that LTE technology is not optimized for rail systems, and especially that LTE does not provide the same native voice capabilities offered by GSM-R. However, the 3GPP standard offers Voice over LTE (VoLTE) that will eventually replace the current 3G Circuit Switched voice service. Voice over IP applications making use of LTE’s IP Multimedia Subsystem (IMS) platform are currently available.
What is even more interesting for the railways is that 3GPP plans to include Push-To-Talk and voice group functionalities in the standard LTE specification, making any sort of “LTE-R” development unnecessary, and further simplifying a future transition of LTE as a voice operational carrier in a railway environment.
Additionally, LTE could provide significant improvements in capacity that could be the basis of a new paradigm in future train control systems, and allow further innovations in safety, operation, passenger services and security.
Future LTE trends include virtualization and miniaturization. Azcom is already offering commercial solutions that can be implemented in an individual hardware platform, that is, all the functions of the eNB and EPC implemented via software over a single blade. This may facilitate C-RAN solutions for mass transit that is very reliable, flexible and scalable with low CapEx and OpEx requirements.
Azcom solutions portfolio for LTE is a unique opportunity for customers who are interested in exploring experimental scenarios of “moving” LTE cells. This would give the ability to demonstrate the enormous advantages of such emerging concept of wireless coverage, where everyone – end-user, transport operator, mobile network operator – can touch the benefits in terms of connectivity, quality of service, customer satisfaction. Possible use cases encompass railway, urban metro trains, buses and commercial fleets.
In terms of products, Azcom provides all the key hardware and software components required to build C-RANs, Small Cells, Network In a Box, Evolved Packet Core, Test Cells, Multi-UE simulators, UE modems and Relay Nodes that makes it possible to design and develop an end-to-end LTE mass transit railway network. All hardware and software components are Azcom owned Intellectual Property, providing customers with a single point of contact for efficient support and rapid customization that is needed for mass transit networks.
Azcom also provides a complete owned solution for the 4G network including the eNB full stack and an optimized and scalable EPC core network, with 3GPP R9 features and committed roadmap to 3GPP R10 and beyond.