RadioScape, the world leader in end-to-end Digital Radio solutions, has provided the Digital Audio Broadcasting (DAB) expertise for a new DAB safety broadcast system for use in road tunnels called RadioScape TunnelAlert. When an incident occurs in a particular tunnel bore, the system is switched in with the effect of replacing the audio on all the DAB audio services being re-broadcast in that tunnel bore with a live emergency message, thus providing the occupants of the vehicles in the tunnel with appropriate instructions. Systems have been in existence to deliver this service on FM for some time but RadioScape is the first company to provide systems for DAB.
Prompted by the Mont Blanc disaster a few years ago, a recent EU mandate requires that long tunnels (over 500 metres) must have an emergency broadcast system that will automatically change the in-car entertainment system to the emergency channel. There are over 2000 tunnels in Europe that will require such a system.
RadioScape has partnered with Tyco Traffic & Transportation, a major systems integration company that specialises in providing radio rebroadcast systems, emergency radio systems and PA/EVAC systems for new and refurbished existing tunnels, to create TunnelAlert. RadioScape used its unique end-to-end systems knowledge of DAB (Digital Audio Broadcast) to create the DAB part of the system. The system provided by RadioScape monitors the specified on-air DAB multiplexes (received outside the tunnel and, in normal conditions, re-broadcast inside), dynamically updating the in-tunnel DAB multiplexer system to follow their configuration. This local multiplexer can then be switched in to replace the rebroadcast signal if an incident occurs, encoding the warning messages in real-time. In this way, all the DAB car radios in the tunnel switch seamlessly from the external service to the warning message.
This was a very complex challenge, explained Les Sabel, Vice President of Development at RadioScape. We have patented the techniques used to effect the seamless and instantaneous transition of all the external DAB broadcasts to the emergency broadcast. David Giles, Business Group Manager for the Wireless Solutions Group at Tyco Traffic & Transportation, added, The EU has recognised the growing importance of DAB in cars and therefore this is a key part of the specifications. Interrupting FM reception is straightforward and we already have systems that can do that part but DAB is more complex requiring the use of a multiplex so we brought in RadioScape. Their Software Defined Digital Radio approach enabled them to create, test and effect all the modifications to their standard equipment via software very quickly.
The first tunnel to have TunnelAlert installed will be the Rotherhithe Tunnel in the UK, which is expected to go live early in the New Year.