infrastructure as they must consider the implications of excluding a large number of their customers from being able to use the network. Similarly, host neutral systems deployed by third-parties can prove highly expensive for operators and can make future network expansion a very complicated business. The optimum solution is cooperation
Wireless systems on trains are far from widespread.
(typically around 800 to 1000 metres apart) and coverage in the tunnels is provided by radiating cable between these repeaters. Another solution is distributed
antenna systems (DAS) which can cover multiple bands across the entire spectrum, as well as being a viable multi- operator solution that is fully compatible with the future deployment of WiMAX and LTE. This makes the technology highly suited to both large volumes of data and public safety transmissions. This is particularly relevant for metro networks, which must handle both a high volume of network traffi c from commuters, as well as ensuring safety through robust communications systems. In addition to the obvious benefi ts to
commuters who desire uninterrupted wireless network access, wireless coverage in metro networks can also offer a host of capabilities that will help improve railway operations. GSM-R is an industry standard that supports high reliability, but low bandwidth transmissions. It can be used for rail operators’ communications needs, such as transmissions between the train driver and the dispatcher. Additionally, the ability for commuters to telephone for assistance can substantially improve
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their sense of safety underground. Also of particular interest to rail companies is Moving Block Operations, which facilitates quicker, more frequent trains by accurately locating and monitoring their positions to the point where they narrowly miss each other, rather than having to occupy specifi c sections of the track.
Operator Cooperation The technical challenges of providing wireless coverage to public transport systems can be overcome with existing technology. Yet, despite this, wireless systems on trains are far from widespread. Many major metro systems around the world do not currently support wireless coverage – perhaps most notably the London Underground, which missed out on gaining coverage after talks fell apart in April last year. While part of the problem has been
a question of engineering, deciding who should actually pay for and install the system has been another. This is primarily a problem for underground deployments, since these are more expensive and present the greatest logistical diffi culties. It is illogical for railway networks to opt for single operator-owned
between a number of operators and stakeholders, who can share the costs of deployment. If operators are able to directly cooperate, installations tend to happen more quickly, at lower costs and result in higher service quality at the end of the project. By sharing the network infrastructure deployed on public transport networks, carriers also share the costs, which can substantially reduce capital and operational expenditure. These savings can then be used to subsidise further network improvements, expansion and next-generation deployments. Such multi-carrier models also mean that commuters can expect ubiquitous connectivity, whatever their network operator. However, this process of cooperation
can be complex and require signifi cant negotiation. For example, one operator might take the lead from a technical perspective, another might cover the initial CapEx investment, while still another might take on the burden of on-going OpEx. Nevertheless, the benefi ts are clear and such joint projects are becoming increasingly common. We recently installed in-train repeaters across a high-speed rail network in Germany as part of a common project between Deutsche Bahn and the German mobile network operators T-Mobile, Vodafone, the E-Plus Group and O2. Despite the hurdles of deploying
public transport wireless coverage, the benefi ts are wide-ranging. Subscribers benefi t from the ability to work or play on the move, operators can harness a new lucrative revenue stream and train operators can promote their networks over those of competitors by advertising their wireless connectivity. Given these advantages, there can be little doubt that those deploying wireless coverage are on the right track.
NETCOMMS europe Volume II Issue 3 2012 19
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