A method and arrangement for improving channel decoding performance in a radio receiver. Data bits from previously decoded messages are analyzed to provide a priori information to a channel decoder which is decoding a currently received message of the same type. The invention may analyze both the header and data fields of the previously decoded message frames to detect fields that are unchanging or rarely changing from one frame to the next. Probabilistic knowledge (a) of the bits in these unchanging or rarely changing fields is then used to improve the decoding performance for the current message. If a message cannot be successfully decoded, soft values of the bits are stored and then soft-combined with selected bits in the next message received prior to decoding. The invention is applicable to any type of message that has data components that are repeated with varying degrees of probability in successive transmissions.