Digital Audio Broadcasting (DAB) works by broadcasting digital signals within a given radio frequency range [in the uk its 217.5 - 230.0 MHz]
The audio signal is digitally encoded, transmitted and then decoded by a DAB unit.
DAB can also be used to broadcast data and text and its this facility
that I think can be further exploited.
If a transmitting unit can send data which can be received elsewhere, then it is possible to have these two units bond by via a handshake protocol.
Once bonded, these units could then transmit data/music/text.
Why do i propose this? If there was a single digital frequency made available for local broadcasting [over a 100m range for example], we could all use radio to transmit where we currently use IR or FM broadcasting. Applications could be
speakers around the house
mp3 or portable cd players in cars