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How do you keep your passengers connected, even while travelling at high-speed?

Posted by Luke Upton on Feb 23, 2017

How do you keep your passenger connected, even at high-speed?The number of mobile phone users in the world is expected to pass the five billion mark by 2019 and most of this huge growth can be attributed to the increasing popularity of smartphones. In 2012, about a quarter of all mobile users were smartphone users, and by 2018 this number is expected to double. And if you are anything like me, your smartphone plays an important part in most aspects of your day. From business e-mails and diary planning to socialising and playing games, the description of your phone as the “remote control for your life” is an accurate one. So it always frustrating when signal disappears or weakens, voice quality fades and data transmissions becomes difficult and your phone becomes an unconnected device. This is something which is all too frequent on-board trains, and not just when going through tunnels either.

But not for passengers on approximately 400 trains and 3,800 carriages owned by Deutsche Bahn (DB) with the German rail giant having signed an agreement in October 2016 with COMLAB for a high quality and modular InTrain mobile telecommunications repeater system. Very simply, a repeater receive a weak or low-level signal and retransmits it at a higher level or higher power. Today we learn more about this technology and how the team at COMLAB are helping ensuring the digital passenger stays connected throughout their journey.

A partnership drawn from the demands of rail passengers, the priority for this project is to increase the levels of on-board satisfaction. Passengers, and especially business travellers using DB trains, expect high quality mobile telecommunications when they travel. This means perfect voice quality and straightforward data transmission.

With very specific demands, a guaranteed solution is required and DB partnered with the Swiss headquartered COMLAB to use their InTrain Repeaters that are designed especially for the sophisticated requirements of high-speed trains. COMLAB’s repeaters compensate for the high levels of signal loss which are caused due to the high isolation levels in modern trains. They also compensate for the extreme variations in the signal levels which are caused by the high-speed trains and the forwarding of one network cell to the next. Plus an Intrain repeater improves the radio link between the passenger’s mobile device and the terrestrial mobile radio station and guarantees undisturbed communication. By overcoming these obstacles, an excellent level of radio communication in the trains can be maintained.

Chapter 4 - DB Trains.jpgThe repeater system satisfies the strict requirements of both the mobile telecommunications network operators and DB. Around 1,200 of the carriages belong to the ICE 4 fleet, the latest generation of Intercity Express high speed trains unveiled at InnoTrans 2016, which will be travelling at speeds of up to 250 km/h (160 mph). The InTrain Repeater System supplies train passengers travelling on DB with 2G, 3G and 4G signals from the mobile telecommunications operators Deutsche Telecom, Telefonica and Vodafone.

The challenge for Comlab, as a company was to bring up the necessary speed and production capacity for the rollout, said Peter Härdi, the new elected CEO of the Comlab Group; “From a technical standpoint Comlab was able to use the broad knowledge and the long history of high frequency projects as a base to fulfil all the highly sophisticated requests from the telecom provider and the German Railways. But the biggest challenge will be to satisfy passenger on-board using their smartphone.”

The team at COMLAB ( @COMLAB_AG ) have over forty years of experience on radio frequency (RF) technology. Their involvement includes design, development, production and installation of turnkey high-frequency radio systems. This expertise and many years of experience ensure they can support their customers in discovering solutions for all of their problems. COMLAB offers systems that are available for all customary frequency ranges and they have the knowledge to bundle different radio technologies into one communication system.

Canva ComLab2.jpgIt’s not just German rail passengers that are benefiting from COMLAB’s solutions, since 2013 their technology has been providing connectivity to travellers on rail-airport link Aeroexpress ( @aeroexpress ) in Moscow, Russia. A new fleet of 25 double-decker trains was ordered from the largest Swiss builder of railway rolling stock, Stadler Rail and these new trains demanded high levels of connectivity.

This project had some major challenges to overcome; airport rail lines generally present significant obstacles to mobile connectivity. The trains carry large numbers of passengers, about 2000 people per journey, the majority of whom will use their phones whilst on-board, and often run through several tunnels. The line also runs and at high speeds of up to 160km/h and these Russian trains that operate in cold weather are well-insulated but this can also block signal.

In order to overcome these challenges and ensure connectivity was available to each passenger, COMLAB employed high-performance and innovative repeaters. They developed an InTrain radio coverage in the form of a highly modular and expandable on-board digital repeater system. Each of the two roof antennas on each trainset receives signals from various landside base stations and forwards them via a coaxial cable to an InTrain repeater inside the train. Each trainset is equipped with two 3-band repeaters. The repeaters first use a band-blocking digital filter to eliminate unwanted signals. In order to use the full capacity of the desired GSM, UMTS and LTE signals in downlink, the repeater amplifies those signals individually for each operator, then forwards the signals via coaxial cable to the InTrain antennas and onto the passengers (read more details on the solution here).

The many customers of the Russian Aeroexpress now benefit from distortion-free and qualitatively outstanding mobile reception, high availability of data services and no dropped calls.

Peter Härdi concludes by telling us about the bright future for this area of the industry; “Today’s phone user is more interested in using the smartphone as a television, watching live events or as a gaming platform and no longer is just focussed on ‘the classics’ like phone-calls or emails on the move. So therefore the bandwidth generated with the 4 and 5G Networks needs to be sufficient not only in centres like Berlin, Frankfurt or Munich, but also on the road and train tracks in between. The challenges are open for the suppliers of Repeater systems and the providers to satisfy that market with generating the necessary network coverage in long distance and local trains, so the end-user is satisfied and can use its product at any time and any situation.”

RTEmagicC_Comlab_03.jpg.jpgThe ability to have high quality and consistent connectivity whilst on-board trains is a key demand for passengers, and an important driver in boosting ridership (and revenue) for rail and metro operators. And with the growth of mobile phone users set to continue to grow, and what they can offer continuing to expand, the ability to use them whilst on a train journey is now an essential offering, and one which COMLAB are helping to offer a growing number of passengers around the world.

For more on the work of COMLAB visit: 

For more railway telecommunications innovations like this... 

Download SmartRail World's FREE and exclusive digital guide - 'Keeping Pace with the Demands of the Digital Passenger' 

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Topics: Telecommunications, Passenger Information Systems

Luke Upton

Written by Luke Upton

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