| CPC H04L 1/0054 (2013.01) [H04B 10/27 (2013.01); H04L 1/0061 (2013.01)] | 18 Claims |
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1. A digital receiver for recovering data from a FEC-encoded signal having a stream of N bits mapped into M transmitted symbols, comprising
a one-dimensional hard demapper for generating a set of K demapped bits for each arriving symbol, where K=ceil(N/M); and
a FEC decoder for producing a stream of decoded data bits from the output of the one-dimensional hard demapper, the FEC decoder including
an apparatus responsive to a set of M*K demapped bits including at least a most-significant bit (MSB) and a least-significant bit (LSB), the apparatus configured to convert the set of M*K demapped bits into a plurality of N log-likelihood ratios (LLRs) associated with the stream of N bits in a one-to-one relationship, the apparatus comprising
at least one processor, and
at least one memory including computer program code, wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus to generate the plurality of N LLRs, each LLR defined by a magnitude and a sign, the magnitude selected from a plurality of predefined, different LLR magnitudes based on at least probability characteristics associated within a bit-specific ordering within the set of M*K demapped bits from the MSB to the LSB, the magnitude of the MSB being greater than at least the magnitude of the LSB; and
a decoding engine responsive to the LLRs generated by the apparatus and producing therefrom an output stream of decoded data bits.
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