RFS: Europe’s unrivalled in-tunnel communications expert

Firmly established in Europe for over 70 years, Radio Frequency Systems, the wireless infrastructure specialist, matches the continent's transportation build-out with the world's most advanced coverage systems.

The European continent, rapidly converging around matters as diverse as the economy, policy, culture, science and technology, is also leading the world in fast, safe and convenient high-speed rail and expressway build-out. Europe's high-speed trains have become a sure reference for like-minded projects around the world, its capitals have continued to flourish and can table sustainability goals thanks enhanced metro systems, forward-thinking road projects have lifted trade and tourism.

However, despite the sustained and parallel growth of Europe's transportation and communication networks, wireless services are in danger of lagging behind high-speed travellers. The truth is that the sudden growth of data traffic past voice traffic levels in many European countries caught operators off-guard and is straining their networks. While highly sophisticated wireless services are overrunning spectrum capacity, they are also in ever higher demand among travellers.

Tunnels, an inseparable part of high-speed rail and expressways, add a level of complexity to the challenge mobile operators and infrastructure owners face. In-tunnel communication systems were once reserved to emergency responders and public transportation personnel, but must now include diverse commercial services for the general public. Defining and implementing in-tunnel wireless coverage systems, which satisfy all the needs of travellers, personnel and emergency units, is an urgent matter calling for expert knowledge.

A full wireless range to cover all tunnels

From an RF communications perspective, there is no "standard" tunnel. All are unique; all demand  purpose-built solutions and attention to design detail. Radio Frequency Systems, firmly established in Europe for over 70 years as a wireless infrastructure leader, developed its indoor coverage capability from this starting point. RFS' technological advantage is based on its customized approach, advanced RF technologies and its full range of value-added services.

A tunnel's shape and length have a direct influence on appropriate coverage methods. As suggested by RFS' many wireless indoor coverage implementation projects around the world, it is necessary to scale coverage solutions according to tunnel field circumstances. A variety of passive and active wireless technology is needed to provide consistent and quality coverage.

Premium products and services

Modern RF communication systems incorporate an increasingly complex "mix" of services. This is particularly so in tunnels, where wireless services may include FM Radio, UHF emergency services and paging along with CDMA800, GSM900, GSM1800, PCS1900  and  W-CDMA2100 (or AWS). In addition there may be a number of operators in some of these bands. In such complex multi-user applications, advanced filter and combiner technology is crucial to total system performance. RFS boasts a leading in-house design competence for such cutting edge point of interface technology.

RFS' RADIAFLEX® range of radiating cables are designed to work as RF broadband, distributed antennas for use in physical spaces that provide extreme challenges to traditional point antenna solutions. These unique cables use a special low loss flexible coaxial cable construction, which includes radiating apertures in the cable's outer conductor. The amount of radiation can be controlled by adjusting the aperture parameters, allowing for performance to be easily tailored for a wide range of application-specific requirements. The cable's low weight and small minimum bend radius expedite installation in locations with restricted access.

In longer tunnels wireless distributed communication systems may require the installation of repeaters. One method of achieving this is to use a fibre-optic backbone system. In support of this constraint and the escalating demand to new data-rich services inside tunnels, RFS has developed the ClearFill suite. RF system requirements can differ greatly from one tunnel to the next, so the ClearFill suite was conceived to provide a range of flexible options to suit all major tunnel systems.

RFS provides the complete bill of material for distributed antenna systems. Commonly these  systems require the distribution of  800-2500 MHz cellular services, but some applications call for additional bands as low as 70 MHz or as high as 6000 MHz. In addition, when all the components are RF broadband, such as RFS product range, wireless in-tunnel systems can simultaneously support multiple applications such as 2G, 3G and WiFi. This way, in-tunnel solution is also future-proof, to support smooth network evolution for example towards 4G/LTE applications in 700 MHz and 2600 MHz.

Decades of experience in delivering high performance RF equipment and skilled services have made RFS very successful around the world. The company has a sound knowledge of international markets, and precise local needs. RFS' truly global services include consulting, site survey, system design, project management, installation, supervision, commissioning, acceptance tests, training and maintenance.

Bringing European technology to the wireless world

In 2008 RFS successfully installed a powerful in-tunnel wireless coverage systems in the stage two development of the UK end of the channel tunnel rail link. The new link runs between the centre of London and Southfleet Junction, approximately 40km (25 miles) to the south-east. Courtesy of a 900MHz Global System for Mobile communications-Railway (GSM-R) upgrade, trains can now travel at 230km/h (143mph). The entire journey from Paris to London now takes only two hours and 15 minutes.

The emerging use of GSM-R for train control in the channel tunnel and other links opens the way for harmonized communications systems throughout the entire pan-European rail network. GSM-R is also gaining acceptance elsewhere, with plans for its implementation throughout Asia. This standard-coupled with premium infrastructure such as RFS ClearFill solution set-stands ready for a key role in enabling trains to move freely across national borders and continents around the world.

Indeed, RFS cable and antenna systems were deployed along Beijing's Metro Line 10 and the Olympic Branch Line, as part of critical upgrades ahead of the 2008 Olympics. In 2009 alone, RFS brought its European technology to the Shenzhen Metro, the Ningbo-Taizhou-Wenzhou Railway and the Wenzhou-Fuzhou High-Speed Railway, and most recently the company outfitted the Shanghai Metro with expert in-tunnel wireless solutions in record time for the World Expo 2010.