Method and apparatus for enhanced performance in a system employing convolutional decoding

A method of decoding an incoming symbol stream, said incoming symbol stream comprising an original symbol stream comprising a first plurality of bits, the first plurality of bits comprising an original plurality of bits with ones of said original plurality of bits deleted, comprising the steps of:

• filling said first plurality of bits with a first set of replacement values which replace the deleted ones of said original plurality of bits to create a first modified symbol stream;
• convolutionally decoding said first modified symbol stream to produce a first decoded information bit stream;
• performing error detection on said first decoded information bit stream;
• and
• if errors are present in said decoded information bit stream, said method further comprising the steps of:
• filling said first plurality of bits with a second set of replacement values to replace the deleted ones of said original plurality of bits, said second set of replacement values different, at least in part, from said first set of replacement values to generate a second modified symbol stream;
• convolutionally decoding said second modified symbol stream to produce a second decoded information bit stream;
• and
• performing said error detection on said second decoded information bit stream.

A method of decoding an incoming symbol stream comprising a first plurality of bits, the first plurality of bits comprising an original plurality of bits with ones of said original plurality of bits overwritten with alternative bits, said method comprising the steps of:

• receiving said incoming symbol stream;
• replacing said alternative bits with a first set of replacement values to generate a first reconstructed approximation of said original plurality of bits;
• convolutionally decoding said first reconstructed approximation to produce a first decoded information bit stream;
• performing error detection on said first decoded information bit stream to ascertain whether errors are present in said first decoded information bit stream;
• and
• replacing said alternative bits with a second set of replacement values to generate a second reconstructed approximation of said original plurality of bits if an error is detected.

An apparatus for decoding an incoming symbol stream having a plurality of known missing symbols, said apparatus comprising:

• means for replacing said plurality of known missing symbols with a first set of values to create a first modified symbol stream;
• means for convolutional decoding said first modified symbol stream to produce a first decoded information bit stream;
• means for performing error detection on said first decoded information bit stream;
• means for re-encoding said first decoded information bit stream to produce a first re-encoded symbol stream if said first decoded information bit stream fails said error detection;
• means for replacing said plurality of known missing symbols within the re-encoded symbol stream with a second set of values to create a second modified symbol stream;
• means for convolutional decoding said second modified symbol stream to produce a second decoded information bit stream;
• and
• means for performing error detection on said second decoded information bit stream.

An apparatus for decoding convolutionally encoded symbol data having a plurality of punctured symbols, said apparatus comprising:

• a demodulator having a soft decision symbol output;
• a depuncture logic having a symbol input in communication with said soft decision symbol output of said demodulator, said depuncture logic configured to replace said punctured symbols with at least one non-zero soft decision value, said depuncture logic having a modified symbol stream output;
• a convolutional decoder having a symbol input in communication with said modified symbol stream output of said depuncture logic and having a decoded information bit stream output;
• a processing unit having a data input in communication with said decoded information bit stream output of said convolutional decoder;
• an encoder having a bit input in communication with said decoded information bit stream output of said convolutional decoder and a symbol output in communication with said symbol input of said depuncture logic;
• and
• an error detection module in said processing unit, said error detection module configured to determine whether errors are present in said decoded information bit stream output of said convolutional decoder, said depuncture logic configured to successively replace said puncture symbols with alternate soft decision values until an error-free decoded information bit stream is detected or a maximum number of trials is reached.