Adaptable overlays for forward error correction schemes based on trellis codes

An apparatus for generating and transmitting auxiliary coded digital information in a communication system, comprising:

• a digital signal source for providing digital signals;
• a convolutional coder connected to the digital signal source, wherein the convolutional coder processes the digital signals to produce a standard set of coded signals and an auxiliary set of coded signals, wherein the standard set of coded signals is created from a first connection polynomial and a second connection polynomial and the auxiliary set of coded signals is created from a third connection polynomial and a fourth connection polynomial;
• a transmission control function connected to the convolutional coder for determining whether to transmit the auxiliary set of coded signals;
• and
• a puncturing function in communication with the convolutional coder, wherein the auxiliary set of coded signals are coupled to the puncturing function.

A method of decoding digitally-encoded data that are received on a plurality of time slots, comprising the steps of:

• collecting data from the plurality of time slots;
• calculating path metrics relevant to a first class of data in a first section of a decoder trellis;
• splitting the first section of the decoder trellis into a second section of a decoder trellis and a third section of a decoder trellis;
• updating the second section of the decoder trellis with the path metrics;
• updating the third section of the decoder trellis with the path metrics;
• identifying a first maximum likelihood path corresponding to the second section of the decoder trellis and a second maximum likelihood path corresponding to the third section of the decoder trellis, both the first maximum likelihood path and the second likelihood path traversing the first section of the decoder trellis;
• identifying a set of decoded data bits from the first maximum likelihood path and the second maximum likelihood path, wherein the bits associated with the first maximum likelihood path pertain to a first class of data and the bits associated with the second maximum likelihood path pertain to a second class of data and the bits pertaining to a third class of data are associated with one of the first maximum likelihood path and the second maximum likelihood path.

An apparatus for generating and transmitting auxiliary coded digital information in a communication system, comprising:

• a digital signal source for providing digital signals;
• a convolutional coder connected to the digital signal source, wherein the convolutional coder processes the digital signals to produce a standard set of coded signals and an auxiliary set of coded signals, wherein the standard set of coded signals is created from a first connection polynomial and a second connection polynomial and the auxiliary set of coded signals is created from a third connection polynomial and a fourth connection polynomial;
• a transmitter, adapted to broadcast the standard set of coded signals in a first transmission slot and the auxiliary set of coded signals in a second transmission slot;
• and
• a transmission control function, coupled to the convolutional coder and adapted to determine whether to transmit the auxiliary set of coded signals.