Digital Audio Broadcasting - DAB - Digital Video and Audio Broadcasting Technology - page 488

The details described in the following section can be found in the
[ETS300401] (DAB), [ETS300799] (ETI) and [ETS300797] (STI) stan-
dards.

DAB data signal

Main Service
Channel MSC

Fast Information
Channel FIC

Up to 64
Subchannels

Multiplex
Configuration
Information
MCI

Fast Information
Data Channel

Audio Data

Stream
Mode

Stream
Mode

Packet
Mode

Fig. 26.24. DAB data structure

A DAB data signal (ETI) is composed of the Fast Information Channel
(FIC) and the Main Service channel (MSC). In the Fast Information Chan-
nel, the modulator and the receiver are informed about the composition of
the multiplexed data stream by means of the Multiplex Configuration In-
formation (MCI). The Main Service Channel contains up to 64 subchan-
nels with a data rate of n•8 kbit/s each. In the subchannels audio signals
and data are transmitted. The modulator and receiver obtain the informa-
tion about the composition of the Main Service Channel from the Multi-
plex Configuration Information (MCI). The transmission in the subchan-
nels can be carried out in Stream Mode and in packet mode. In Stream
Mode, data are transmitted continuously. In Packet Mode, the subchannel
is additionally sub divided into sub-packets with a constant length. Audio
is always transmitted in Stream Mode. The data structure is here pre-
determined by the audio coding (24/48 ms pattern). Data can be transmit-
ted in Packet Mode (e.g. MOT - Multimedia Object Transfer) or in Stream
Mode (e.g. T-DMB). In Packet Mode, the most varied data streams can be
transmitted within a subchannel.
In Stream Mode, a subchannel is used completely for a continuous data
stream. This is the case e.g. during audio transmission. Data can also be