Patent ID: 9647696
Date: 2017-05-09
CPC Classifications: H03M,H04L

Claim:
1. A method comprising: obtaining a forward error corrected and differentially encoded signal received via a communication channel; supplying the differentially encoded signal to a soft-input soft-output (SISO) differential decoder that is bi-directionally coupled to a SISO forward error correction decoder; and over a first and initial portion of a plurality of decoding iterations for a given frame of the differentially encoded signal, operating the SISO differential decoder and the SISO forward error correction decoder in a turbo decoding mode in which soft-decision messages generated by the SISO differential decoder are passed to the SISO forward error correction decoder and forward error correction messages generated by the SISO forward error correction decoder are passed to the SISO differential decoder; and over a second and final portion of the plurality of decoding iterations for the given frame of the differentially encoded signal, operating the SISO differential decoder and the SISO forward error correction decoder in a non-turbo decoding mode in which the SISO forward error correction decoder operates without any messages passing to and from the SISO differential decoder; and obtaining decoder output from the SISO forward error correction decoder; wherein the first and initial portion of decoding iterations comprises a first predetermined number of decoding iterations for the given frame and the second and final portion of decoding iterations comprises a second predetermined number of decoding iterations for the given frame, and wherein operating in the non-turbo decoding mode for the second predetermined number of decoding iterations is performed after operating in the turbo decoding mode for the first predetermined number of decoding iterations.