Mobile communications for rail passengers: objectives, challenges and solutions.

SBB's mobile telecommunications strategy is centred on maximising customer benefits: on board trains we are using repeaters, and at railway stations we are focusing on free Internet access. We are also in regular contact with mobile telecommunications providers with regard to provision across the rail network.

At stations.

SBB offers free wi-fi to customers at its busiest stations so that they can surf the web, work and synchronise e-mails at the station.

Key figures: Investments of over CHF 10 million. Equipping the 80 or so busiest stations from September 2013 until November 2015.

In trains.

To ensure that passengers can enjoy mobile reception inside trains as well as outside, all planned long-distance coaches have been fitted with state-of-the-art repeaters (2G/3G/4G). Mobile telecommunications providers, SBB and the FOT are also planning to equip regional rolling stock with repeaters.

Key figures: Signal loss amounts to around 30 dB; long-distance fleet of approximately 1,083 coaches and 51 multiple-unit trains equipped with repeaters since the end of 2014; it will be possible to fit out the regional rolling stock between 2016 and 2020.

Across the rail network.

Three mobile telecommunications suppliers provide passengers with mobile connectivity while they are on the move. This calls for adequate, stable network coverage for the high numbers of passengers involved. In this context, SBB is representing rail passengers' interests and maintaining contact with all three mobile telecommunications providers to ensure that sufficient investment planning priority is given to covering railway lines, which act as an important link between populated areas. SBB also supports mobile telecommunications providers by enabling them to locate their antennae on SBB infrastructure where this is operationally feasible.

Key figures: Most main railway lines including tunnels are now covered by 3G, and 4G coverage is underway; regional lines still have varying degrees of coverage, in particular outlying areas. For details of current network coverage, please contact the relevant mobile telecommunications providers.

At stations.

SBB WiFi – where is this service provided and how does it work?

SBB provides the free service SBB WiFi at around 80 of the most frequented railway stations. Customers have to personally activate each of their mobile devices in order to use the service – this is a legal requirement and is clearly stated in the terms and conditions of use. Activation takes just two clicks, via a text message and an access code. Following this registration procedure, SBB WiFi can be used at all suitably equipped railway stations with no need to re-register. The service is restricted to 60 minutes of uninterrupted Internet access. Customers can then continue surfing at a different station, or at the same station following a two-hour break.

Data protection – what data does SBB gather, why, and what does it do with it?

As an Internet service provider, SBB is legally required to register and identify every one of its customers. This is done via SMS as each SIM card can now be uniquely associated with a single person. According to the federal law on the surveillance of post and telecommunications traffic, Internet service providers are also required to collect usage data so that illegal activities can be traced if necessary. The usage data that is collected includes:

• MAC address
• Current IP address
• Sources: IP and MAC address
• Source and destination port (TCP/UDP)
• Login / logout time

No content data, e.g. e-mails or transmitted content, is recorded during the registration process. This data is not passed on to any third parties and is stored in accordance with statutory requirements.

SBB wants to expand the personalised, location-specific information and services it provides – this is a clear customer requirement. SBB will display advertising and customer information on the home page for the free service (pop-ups and banners), but there are no plans to send any promotional mailshots or make any phone calls.

On trains.

SBB has opted to use modern signal amplifiers (repeaters). How do these work?

Signal amplifiers (repeaters) are used where insulation severely suppresses mobile phone signals (the Faraday cage effect). This is often the case in modern office buildings and also in air-conditioned trains. In such cases, repeaters are the key to mobile Internet access. They bridge the train's metal exterior and insulated windows, which block off most of the mobile phone signal. Three key components are needed:

• An external antenna: A small antenna is mounted on the outside of the train. This connects directly to the mobile phone network.
• Internal antennae: An antenna cable is inserted into each coach (and on each deck). This ensures even coverage throughout the coach and connects directly to passengers' mobile devices.
• Repeater: The repeater links the external antenna and the internal antennae and boosts the signal so that passengers get reception that is as good as they would receive outside the train.

Incidentally, when it comes to upgrading to the latest generation of repeaters, Switzerland leads the way in Europe. Customers on a number of routes can already surf the web using 4G LTE technology.

Concerns that such systems lead to increased radiation emissions are unfounded. On the contrary, without repeaters, all active mobile devices in a coach will switch to full power in order to use the (very weak) phone signal that is available. In coaches that have repeaters, all equipment reduces its transmission power to a minimum.

Customers want wi-fi on trains – why has SBB not opted to use this technology?

SBB has made a conscious decision not to have wi-fi on trains because the repeaters it has installed already provide good reception on the move.

There are two main reasons for deciding against having wi-fi on trains:

1. An on-board wi-fi service would also use mobile telecommunications networks outside the train itself, and would provide passengers with very little extra bandwidth over and above that provided by a good direct 3G/4G connection thanks to repeaters. Any wi-fi system would be installed in addition to repeaters rather than as an alternative.
2. Customer surveys clearly show that wi-fi would only be used if it were free of charge. Since wi-fi systems use 3G/4G to access the Internet, they would incur hefty charges for the 3G/4G data volumes used by passengers, which SBB would have to pay to the mobile telecommunications providers. Calculations show that these costs would rapidly rise into the hundreds of millions of Swiss francs. The general public would have to fund these additional costs, with due consideration of cost transparency and the «user pays» principle. SBB is opposed to this type of subsidy for mobile telecommunication services.

The only equipment not covered by this arrangement is those devices that do not have SIM cards. These cannot establish a direct connection to the Internet, and instead have to use a WLAN. Around 70 percent of passengers today have access to a smart phone that can be converted into a wi-fi antenna using «mobile hotspot» functionality. Passengers can use this functionality (known as tethering) to connect their laptops or tablets to the Internet, but they have to pay the connection costs themselves via their mobile phone contract.

SBB's decision is the correct one given the situation in Switzerland with its relatively short journey times and three well-established mobile telecommunications networks. In other countries, however, WLANs on trains might be absolutely the right way to go:

• In countries where mobile telecommunications networks are not as well established, wi-fi can improve the quality of connectivity significantly because wi-fi systems always select the best network and therefore generally establish more stable connections. However, this effect is negligible in Switzerland due to the excellent coverage supplied by all three providers.
• In countries with long journey times, wi-fi systems are combined with in-train infotainment systems so that passengers on multi-hour journeys can view films or play games (usually for a charge).
• In countries where there is fierce competition in the mobile telecommunications market, there are also situations in which mobile telecommunications providers will cover the costs for on-board wi-fi systems for marketing reasons, to secure a competitive advantage.

Added to this, roaming prices across Europe are coming under pressure and flat rates are set to become more widespread. In the interests of its customers, SBB is pursuing a long-term strategy and is convinced that the demand for free wi-fi will decrease over the next few years.

Why is Internet access on trains so slow compared with at home or in the office?

Due to high train speeds and the large number of users sharing bandwidth, it is never going to be possible for on-board access to be as fast as stationary access.

The two hurdles faced on trains are the high number of users and the speed.

• If a train is full of passengers who all want to be online at the same time, up to 1,200 passengers will be using the mobile telecommunications network. On a mobile network, capacity is shared amongst all subscribers, so there won't be much available for each individual person.
• If a train is travelling at 200 km/h, mobile customers will be passed from one cell to the next every 20 seconds. And this will be happening to up to 1,200 people per train (400m) at the same time. (In an extreme case where two trains are passing each other in opposite directions there could be 2 x 1,200 = 2,400 people).

Various subscriptions offered by Swiss mobile telecommunications providers are resulting in many customers using their smartphones and tablets extensively on the train, leading to a rapid growth in data volumes.

Swiss legislation is also having a significant impact on the situation, as it massively reduces the transmission power of mobile phone antennae compared with that in other European countries. Swiss mobile phone antennae have one tenth of the transmission power of comparable antennae abroad, making it very difficult and expensive to provide good uninterrupted connectivity across the rail network. And since people are opposing the construction of new antennae, data capacity will remain restricted in the future too.

Facts on mobile phones.

SBB rolling stock.

Long-distance services: 1,083 air-conditioned coaches and 51 multiple-unit trains are equipped with repeaters.

Regional services: SBB and the Mobilfunkanbieter plan on installing repeater in about 1700 coaches of the regional services by 2022.

Status of upgrade to long-distance services.

To date, all of the long-distance trains (EC, ICN, EWIV and IC2000, excluding 19 ETR 610 trains) have been fitted out, with the upgrade programme having been completed at the end of 2014.

InTrainCom.

Consortium of three mobile telecommunications providers, Swisscom, Sunrise and Salt, that is operating and (partially) funding the repeaters.

Repeater / signal amplifier.

System for bridging insulation that suppresses mobile phone signals. Modern signal amplifiers improve 2G/3G/4G transmission by mobile devices using the rapid data standards GSM, EDGE, UMTS, HSPA, HSPA+ and LTE.

Wi-fi on trains.

SBB has made a conscious decision not to have wi-fi on trains because the repeaters it has installed already provide good reception on the move. The value added by wi-fi would therefore be limited, but the costs (of purchasing mobile bandwidth from providers) would be very high.

When it comes to upgrading to the latest generation of repeaters, Switzerland leads the way in Europe. Customers on a number of routes can already surf the web using 4G LTE technology.

Mobile phone antennae in Switzerland.

Their transmission power is around one tenth of that of comparable antennae in neighbouring countries. This is due to the requirements of the Ordinance on Non-Ionising Radiation (ONIR).

Power sockets next to seats.

28,500 power sockets on trains for charging laptops, mobile phones and tablets.

Difference compared with wi-fi projects run by bus and municipal tram operators.

It is significantly easier to transmit data from road vehicles due to the slower speeds and smaller numbers of users involved. The bandwidth is restricted even in buses that have wi-fi. Fewer capacity bottlenecks occur due to the significantly smaller number of users per vehicle.

Facts on wi-fi at stations.

Wi-fi at stations.

SBB provides the free service SBB WiFi at around 80 of the most frequented railway stations. After registering just once, free Internet access is available at all suitably equipped stations. Time restriction: 60 minutes, followed by a two-hour break or use at another station.

Investment in the wi-fi service.

A low eight-figure sum is being invested in this service

The cost of operating the wi-fi service.

The operating costs, which are into the low single-digit millions of Swiss francs, are largely covered by advertising revenue.

Wi-fi / WLAN.

In many countries (including the USA, the UK, France, Italy and latterly also Germany), the term wi-fi is used synonymously with WLAN.