A method for a source-controlled channel-decoding of data in a frame format includes the steps of channel-decoding a given frame of data, determining an a-posteriori information based on a reliability decision of the channel-decoding and/or a source-decoding subsequent to the 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.