FIC, FIB, FIG
The FIC constitutes, next to MSC, one of three separate DAB data channels which conveys, among other, binary information on how the DAB multiplex is organized. Every DAB receiver must process this essential on-air tuning data. The service list for the desired DAB service selection is built by the DAB receiver upon FIC decoding.
The FIC is a non-time-interleaved data channel with fixed equal error protection. In each Transmission frame the FIC is adjacent to the Synchronization channel in the Transmission frame.
The FIC consists of multiple FIBs. As  describes it, FIB is a
data burst of 256 bits. Each FIB contains 30 bytes of data and 16 bits of CRC. The number of FIBs per transmission frame in particular mode is shown in Table 1.
|Number of FIBs||12||3||4||6|
|Number of CIFs||4||1||1||2|
Modes that feature multiple CIFs allocate FIBs evenly to each CIF, i.e. for mode IV: FIB#0-2 → CIF#0, FIB#3-5 → CIF#1.
DataDecoder class is used to extract information from FIC. It consists of functions realizing such tasks as de-puncturing, Viterbi decoder, energy de-dispersal, CRC checking of FIBS and FIBs building.
Each FIB is divided into Fast Information Groups (FIGs), which include specific information about transmission, available stations, their names and their configuration.
typeis a number between 0 and 7. For transmission 0 and 1 are most important, but type 5 is expected to contain information about traffic or emergency messages, and data channel should be carried in type 6. In the light of the implementation the division is more simple; 3 cases need to be considered:
- extension 0,
- extensions 1, 2, 5, 6,
- extension 7, where resides information about the end marker, if
datafield equals 31.
Picture above illustrates organization of FIG type 0, other types are almost the same. The differences are:
extension is smaller (3 bits instead of 5) and there are different parameters in the beginning.
FIG type 0 extension 1 and 2 deserve special attention, as they convey information about channels (stations) and their attributes. Also, in extension 2 there are fields which can be used to link a sub channel with its id, and hence with station name from FIG type 1 extensions 0 and 1. Other data, like current time or transmitter coordinates, can be found in other extensions of FIG type 0. On the other hand FIG type 1 handles simple labels like multiplex name or station name.
- ETSI EN 300 401
- ETSI TR 101 496-2