Method and apparatus for decoding an encoded signal

An apparatus for decoding an encoded signal, the encoded signal having been interleaved by a transmitter, the apparatus comprising:

• (a) a receiver for receiving the encoded signal and processing the encoded signal into a form suitable for deinterleaving;
• (b) a deinterleaver, coupled to the receiver, for producing a set of log-likelihood values;
• (c) a conditional soft decision metric generator for generating a set of conditional soft decision metrics from the set of log-likelihood values;
• (d) a bit metric generator for generating bit metrics from the set of conditional soft decision metrics based upon a hard coded symbol value;
• (e) a branch metric generator for generating a plurality of branch metrics from a series of bit metrics;
• (f) a path metric calculator for determining a path metric based on the plurality of branch metrics;
• (g) a trellis calculator for estimating the signal from the path metric;
• and
• (h) a convolutional encoder for encoding a set of path decision history data into the hard coded symbol value supplied to the bit metric generator.

A method of decoding an encoded signal, the encoded signal having been interleaved by a transmitter, the method comprising the steps of:

• (a) receiving the encoded signal and processing the encoded signal into a form suitable for deinterleaving;
• (b) producing a set of log-likelihood values;
• (c) generating a set of conditional soft decision metrics from the set of log-likelihood values;
• (d) generating bit metrics from the set of conditional soft decision metrics based upon a hard coded symbol value;
• (e) generating a plurality of branch metrics from a series of bit metrics;
• (f) determining a path metric based on the plurality of branch metrics;
• (g) estimating the signal from the path metric;
• and
• (h) encoding a set of path decision history data into the hard coded symbol value supplied to a bit metric generator.