Service following
Service following is the term applied to maintaining the same audio or data content that the user has selected in varying reception conditions when travelling by car or train
Many broadcast network topologies are possible - the tuned service may be carried on an ensemble with multiple tuning frequencies on more than one ensemble, may carry common programming with other DAB services, and for audio services may also be carried on FM-RDS or another bearer.
The best service following experience for the listener is achieved when the broadcaster minimises the timing differences between different bearers, taking into consideration the different coding and decoding delays of the different systems. Reliable service following also requires that all the identifiers used are properly allocated in such a way as to make them unique within their respective scope.
Until DAB coverage has reached sufficient levels in all markets there needs to be provision for broadcasters to implement service following and linking from DAB-FM / FM-DAB, thereby allowing a seamless listening experience on the move.
To assist broadcasters and to ensure that receiver manufacturers worldwide implement service following correctly, WorldDAB has produced the following resources:
Rules of implementation: Service information features ETSI TS 103 176
Service following and traffic announcements technical trial: UK April 2013