Code generator and decoder for communications systems operating using hybrid codes to allow for multiple efficient users of the communications systems

An encoder that encodes data for transmission from a source to a destination over a communications channel, the encoder comprising:

• an input for receiving an ordered set of source symbols representing the data to be encoded;
• first logic for generating a first set of repair data generated from the source symbols according to a first FEC code;
• second logic for generating a second set of repair data generated from the source symbols according to a second FEC code, the second FEC code being more complex than the first FEC code where complexity is a measure of computational effort required to generate repair symbols;
• and
• an output for outputting at least the first set of repair data and the second set of repair data,
• wherein the first and second sets of repair data are constructed such that the original ordered set of source symbols is recoverable with less information than would be required if using the received FEC repair data from only one of the first and second set of repair data.

A decoder for decoding information received over a communications channel, possibly with errors and/or erasures and/or lost or missing information, from an encoder, the decoder comprising:

• an input for receiving symbols from the communications channel;
• logic for identifying whether a received symbol represents a source symbol of the encoded data, a first type of repair symbol for recovering lost, incorrect or missing information of the encoded data or a second type of repair symbol for recovering lost, incorrect or missing information of the encoded data, wherein the first type of repair symbol is a repair symbol generated from the source symbols according to a first FEC code and the second type of repair symbol is a repair symbol generated from the source symbols according to a second FEC code, the second FEC code being more complex than the first FEC code where complexity is a measure of computational effort required to generate repair symbols;
• and
• logic for using at least the received source symbols, at least one repair symbol of the first type and at least one repair symbol of the second type to recover the encoded data, such that the encoded data is recovered with less information than would be required if only one of the first type of repair symbol or the second type of repair symbol are used.

A method of decoding transmitted data that encodes for a set of source symbols transmitted over a communications channel, the method comprising:

• receiving symbols from the communications channel;
• identifying whether a received symbol represents a source symbol of the encoded data, a first type of repair symbol for recovering lost, incorrect or missing information of the encoded data or a second type of repair symbol for recovering lost, incorrect or missing information of the encoded data, wherein the first type of repair symbol is a repair symbol generated from the source symbols according to a first FEC code and the second type of repair symbol is a repair symbol generated from the source symbols according to a second FEC code, the second FEC code being more complex than the first FEC code where complexity is a measure of computational effort required to generate repair symbols;
• and
• using at least the received source symbols, at least one repair symbol of the first type and at least one repair symbol of the second type to recover the encoded data, such that the encoded data is recovered with less information than would be required if only one of the first type of repair symbol or the second type of repair symbol are used.

A system for encoding data for transmission from a source to a destination over a communications channel, the system comprising:

• means for generating from an ordered set of source symbols FEC repair data according to a first code, the ordered set of source symbols representing the data to be encoded;
• means for generating from the ordered set of source symbols FEC repair data according to a second code, the second code being more complex than the first code;
• and
• means for sending the source symbols, the first set of FEC repair data and the second set of FEC repair data, such that received data that includes some or all of the sent data is decodable and the original source block of data is recoverable, wherein the first and second sets of FEC repair data are constructed such that the original source block of data is recoverable with less information than would be required if using the received FEC repair data from only one of the two FEC codes and the FEC decoder for that FEC code and the received original source block data.

A system for decoding transmitted data that encodes for a set of source symbols transmitted over a communications channel, the system comprising:

• means for receiving symbols from the communications channel;
• means for identifying whether a received symbol represents a source symbol of the encoded data, a first type of repair symbol for recovering lost, incorrect or missing information of the encoded data or a second type of repair symbol for recovering lost, incorrect or missing information of the encoded data, wherein the first type of repair symbol is a repair symbol generated from the source symbols according to a first FEC code and the second type of repair symbol is a repair symbol generated from the source symbols according to a second FEC code, the second FEC code being more complex than the first FEC code where complexity is a measure of computational effort required to generate repair symbols;
• and
• means for using at least the received source symbols, at least one repair symbol of the first type and at least one repair symbol of the second type to recover the encoded data, such that the encoded data is recovered with less information than would be required if only one of the first type of repair symbol or the second type of repair symbol are used.

A computer program product for encoding data for transmission from a source to a destination over a communications channel, the product comprising:

• a processor-readable medium storing processor-readable instructions configured to cause a processor to:
• obtain an ordered set of source symbols representing the data to be encoded using the generated output symbols and an encoding for the data;
• generate FEC repair data according to a first code;
• generate FEC repair data according to a second code, the second code being more complex than the first code;
• and
• provide for sending the source symbols, the first set of FEC repair data and the second set of FEC repair data, such that received data that includes some or all of the sent data is decodable and the original source block of data is recoverable, wherein the first and second sets of FEC repair data are constructed such that the original source block of data is recoverable with less information than would be required if using the received FEC repair data from only one of the two FEC codes and the FEC decoder for that FEC code and the received original source block data.

A computer program product for decoding transmitted data that encodes for a set of source symbols transmitted over a communications channel, the product comprising:

• a processor-readable medium storing processor-readable instructions configured to cause a processor to:
• obtain symbols received from the communications channel;
• identify whether a received symbol represents a source symbol of the encoded data, a first type of repair symbol for recovering lost, incorrect or missing information of the encoded data or a second type of repair symbol for recovering lost, incorrect or missing information of the encoded data, wherein the first type of repair symbol is a repair symbol generated from the source symbols according to a first FEC code and the second type of repair symbol is a repair symbol generated from the source symbols according to a second FEC code, the second FEC code being more complex than the first FEC code where complexity is a measure of computational effort required to generate repair symbols;
• and
• use at least the received source symbols, at least one repair symbol of the first type and at least one repair symbol of the second type to recover the encoded data, such that the encoded data is recovered with less information than would be required if only one of the first type of repair symbol or the second type of repair symbol are used.