Digital audio broadcasting method using puncturable convolutional code

A radio frequency transmitter comprising:

• means for encoding program material using convolutional codes having non-puncturable bits and puncturable bits;
• means for modulating a plurality of orthogonal frequency division multiplexed carrier signals with said convolutional codes, whereby said non-puncturable bits are carried by a first group of said carrier signals and said puncturable bits are carried by a second group of carrier signals, said first group of carrier signals being less susceptible to interference than said second group of carrier signals;
• and
• means for broadcasting said carrier signals.

A radio frequency receiver comprising:

• means for receiving a plurality of orthogonal frequency division multiplexed carrier signals with convolutional codes containing puncturable and non-puncturable bits, wherein said non-puncturable bits are carried by a first group of said carrier signals and said puncturable bits are carried by a second group of said carrier signals, said first group of said carrier signals being less susceptible to interference than said second group of said carrier signals;
• means for determining if carrier signals in said second group of said carrier signals have been corrupted;
• means for erasing puncturable bits carried by any of said carrier signals which have been determined to be corrupted to produce punctured codes;
• and
• means for decoding said punctured codes.

A radio frequency receiver comprising:

• means for receiving a plurality of orthogonal frequency division multiplexed carrier signals with convolutional codes containing puncturable and non-puncturable bits, wherein said non-puncturable bits are carried by a first group of said carrier signals and said puncturable bits are carried by a second group of said carrier signals, said first group of said carrier signals being less susceptible to interference than said second group of said carrier signals;
• means for determining if carrier signals in said second group have been corrupted;
• means for weighting puncturable bits carried by any of said carrier signals which have been determined to be corrupted to produce weighted convolutional codes;
• and
• means for decoding said weighted convolutional codes.

A method of receiving a radio frequency signal comprising the steps of:

• receiving a plurality of orthogonal frequency division multiplexed carrier signals with convolutional codes containing puncturable and non-puncturable bits, wherein said non-puncturable bits are carried by a first group of said carrier signals and said puncturable bits are carried by a second group of said carrier signals, said first group of said carrier signals being less susceptible to interference than said second group of said carrier signals;
• determining if carrier signals in said second group of said carrier signals have been corrupted;
• erasing puncturable bits carried by any of said carrier signals which have been determined to be corrupted to produce punctured codes;
• and
• decoding said punctured codes.

A method for receiving a radio frequency signal comprising the steps of:

• receiving a plurality of orthogonal frequency division multiplexed carrier signals with convolutional codes containing puncturable and non-puncturable bits, wherein said non-puncturable bits are carried by a first group of said carrier signals and said puncturable bits are carried by a second group of said carrier signals, said first group of said carrier signals being less susceptible to interference than said second group of said carrier signals;
• determining if carrier signals in said second group have been corrupted;
• weighting puncturable bits carried by any of said carrier signals which have been determined to be corrupted to produce weighted convolutional codes;
• and
• decoding said weighted convolutional codes.