People traveling through the Channel Tunnel can now access mobile services 100 meters under the sea -- as long as they are heading to the U.K., rather than crossing over to France.
French operators Bouygues Telecom, Orange and SFR have all started providing 2G and 3G services in the south tunnel -- which runs from France to the U.K. -- enabling passengers and drivers on the Eurostar, Shuttle and Freight service to use their phones under the English Channel.
However, British operators will not begin offering similar services in the north tunnel -- taken when traveling from the U.K. to France -- until the Olympic games are over.
"Eurotunnel is proud to be able regularly to improve the services we offer to our customers through major technological innovation, this time based on the expertise of Alcatel-Lucent," Groupe Eurotunnel technical director Jacques Gounon said.
A special regulatory framework had been agreed to by both Ofcom and the French regulator equivalents -- Arcep and ANFR -- in order to allocate the required spectrum, according to Orange, with installation of the system along the 53km tunnel taking 10 months.
Transmission proved an obstacle for the operators involved in the scheme. One problem in particular was how to synchronize the GSM-P (primary GSM) and GSM-R (railway GSM) systems to work together inside the tunnel.
"Leaky feeder" technology was implemented in order to cross this bridge and keep connectivity going under the stretch of water -- which basically involves the use of a long broadcast cable that serves as an antenna. The cable both "leaks" and receives radio signals, secured through 72 optical repeaters spaced out every 750 meters. Base stations were then constructed by Orange at either end of the south tunnel to fully connect the network.
"As a result of this collaboration with Eurotunnel, and which has used many of the different technical skills we have at Alcatel-Lucent, we are very proud to have contributed to the provision of new communication services on board the trains in the Channel Tunnel," Alcatel-Lucent France chief Pascal Homsy said.
However, the Brits need to be aware that while French customers of Orange will enjoy mobile services on the Channel Tunnel as part and parcel of their standard tariffs, for now at least, U.K. customers using 2G or 3G are subject to roaming charges -- despite half of the journey being under U.K. jurisdiction.