channel decoding calculating an a priori information based on the a posteriori information and based on a residual redundancy of the data and channel decoding the given frame once more using the a priori information the method thus uses the residual correlation between bits in a frame the method preferably uses the intra frame correlation in a gsm system a channel decoder configuration is also provided application_number US 46034599 A description referring now to the figures of the drawings in detail and first particularly to fig1 thereof there is shown a basic structure of a source controlled channel decoder according to the invention as has already been stated above according to the invention the residual redundance between bits of a parameter is evaluated within one frame in order to perform source controlled channel decoding in order to determine this intra frame correlation of the bits the invention proposes a method based on a repeated channel decoding as illustrated in fig1 encoded data are fed on a transmission channel 4 to a channel decoder 1 in a frame format for example the gsm standard this channel decoder 1 may be for example a so called sova soft decision viterbi algorithm or a map a posteriori maximum probability decoder in these decoders the received signal is compared with all the basically possible signals and the signal which is most similar to the received signal is then selected according to this example the encoded data which are supplied on the transmission channel 4 are.