unequal error protection (audio codec) (UEP)

Unequal Error Protection (UEP) is a technique used in DigitalAudio Broadcast(DAB) whose protection is controlled by the priority of the transmitted bits. This contrasts with Equal Error Protection ( EEP), where all data bits are given the same redundancy.

In the DAB data frame, the first bit group is very important because it contains the header with the bit allocation information( BAL) and information about the number of transmitted scale factors (SCFSI). The second bit group contains the scale factors and the third contains the audio data which has the least error protection. The fourth bit group contains the program accompanying data( PAD) and the cyclic block check(CRC), which in turn have higher error protection.

The advantage of the imbalance is the reduction of the data rate. If all bit groups had the same error protection, the data volume would be much higher.