To enhance decoding method, when the decoding method of information subjected to turbo coding does not converge.

First information with a set of initial weights is received from a demodulator input and fed to a turbo decoder 70. The decoded information is fed to an error detector 71 which controls a switch 72 and is re-coded for a caption 73 when the information has no error or for a turbo coder 74, corresponding to the turbo decoder 70 when an error exists in the information and an operator 75 converts the coded information into a weighted value. The weighted value is multiplied with an attenuation coefficient α (76), before it is subtracted from the initial weight value, the corrected input information is again turbo-decoded and an error is detected newly. This detection is continued, until error is no longer found in the turbo decoded information, or the information reaches a certain value of service quality.