Severe error detectors, methods and computer program products that use constellation specific error event thresholds to detect severe error events during demodulation of a signal comprising symbols from a plurality of symbol constellations

A method of detecting severe error events, comprising the steps of:

• defining a plurality of constellation thresholds that correspond to a plurality of symbol constellations;
• receiving an output signal sample that is associated with one of the plurality of symbol constellations from a decision feedback equalizer, the decision feedback equalizer comprising a digital filter characterized by a set of coefficients;
• comparing an absolute value of the output signal sample with the constellation threshold that corresponds with the symbol constellation associated with the output signal sample;
• recognizing a severe error only if the absolute value of the output signal sample exceeds the constellation threshold that corresponds with the symbol constellation associated with the output signal sample;
• determining if a number of severe error occurrences exceeds a first error event threshold;
• and
• preventing the coefficients from being updated to new values if the number of severe error occurrences exceeds the first error event threshold.

A computer program product for detecting severe error events, comprising:

• a computer readable storage medium having computer readable program code embodied therein, the computer readable program code comprising:
• computer readable program code for defining a plurality of constellation thresholds that correspond to a plurality of symbol constellations;
• computer readable program code for receiving the output signal sample that is associated with one of the plurality of symbol constellations from a decision feedback equalizer, the decision feedback equalizer comprising a digital filter characterized by a set of coefficients;
• computer readable program code for comparing an absolute value of the output signal sample with the constellation threshold that corresponds with the symbol constellation associated with the output signal sample;
• computer readable program code, responsive to the computer readable program code for comparing, for recognizing a severe error only if the absolute value of the output signal sample exceeds the constellation threshold that corresponds with the symbol constellation associated with the output signal sample;
• computer readable program code for determining if a number of severe error occurrences exceeds a first error event threshold;
• and
• computer readable program code, responsive to the computer readable program code for determining, for preventing the coefficients from being updated to new values if the number of severe error occurrences exceeds the first error event threshold.

A severe error detector, comprising:

• means for defining a plurality of constellation thresholds that correspond to a plurality of symbol constellations;
• a decision feedback equalizer that is configured to receive an output signal sample that is associated with one of the plurality of symbol constellations, the decision feedback equalizer comprising a digital filter characterized by a set of coefficients;
• means for comparing an absolute value of the output signal sample with the constellation threshold that corresponds with the symbol constellation associated with the output signal sample;
• means, responsive to the means for comparing, for recognizing a severe error if the absolute value of the output signal sample exceeds the constellation threshold that corresponds with the symbol constellation associated with the output signal sample;
• means for determining if a number of severe error occurrences exceeds an error event threshold;
• and
• means, responsive to the means for determining, for preventing the coefficients from being updated to new values if the number of severe error occurrences exceeds the error event threshold.

A method of detecting severe error events, comprising the steps of:

• defining a plurality of constellation thresholds that correspond to a plurality of symbol constellations;
• receiving an output signal sample that is associated with one of the plurality of symbol constellations from a decision feedback equalizer, the decision feedback equalizer comprising a digital filter characterized by a set of coefficients;
• comparing an absolute value of the output signal sample with the constellation threshold that corresponds with the symbol constellation associated with the output signal sample;
• recognizing a severe error if the absolute value of the output signal sample exceeds the constellation threshold that corresponds with the symbol constellation associated with the output signal sample;
• determining if a number of severe error occurrences exceeds an error event threshold;
• and
• preventing the coefficients from being updated to new values if the number of severe error occurrences exceeds the error event threshold.

A computer program product for detecting severe error events, comprising:

• a computer readable storage medium having computer readable program code embodied therein, the computer readable program code comprising:
• computer readable program code for defining a plurality of constellation thresholds that correspond to a plurality of symbol constellations;
• computer readable program code for receiving an output signal sample that is associated with one of the plurality of symbol constellations from a decision feedback equalizer, the decision feedback equalizer comprising a digital filter characterized by a set of coefficients;
• computer readable program code for comparing an absolute value of the output signal sample with the constellation threshold that corresponds with the symbol constellation associated with the output signal sample;
• computer readable program code, responsive to the computer readable program code for comparing, for recognizing a severe error if the absolute value of the output signal sample exceeds the constellation threshold that corresponds with the symbol constellation associated with the output signal sample;
• computer readable program code for determining if a number of severe error occurrences exceeds an error event threshold;
• and
• computer readable program code, responsive to the computer readable program code for determining, for preventing the coefficients from being updated to new values if the number of severe error occurrences exceeds the error event threshold.