INCREASING ERROR CORRECTION IN DATA STREAMS ENCODED WITH LINEAR BLOCK CODE
First Claim
1. A receiver that receives a data stream of modulated data symbols that have been encoded with a linear block code comprising:
- a comparator that compares said data symbols with at least one limit that indicates impairment of said data symbols;
an output control signal generated by said comparator that marks said corrupt data symbols in said data stream; and
a decoder that is connected to said comparator that receives said output control signal and erases said corrupt data symbols that are marked by said output control signal prior to performing error corrections so as to increase error correction capabilities of said decoder.
2 Assignments
0 Petitions
Accused Products
Abstract
Disclosed is an apparatus and method for increasing the error correction capabilities of a receiver circuit that receives a data stream of encoded data symbols that are encoded with a linear block code. Analog and digital comparator circuits are used to detect laser clipping or analog to digital converter overloading. Corrupted symbols are detected by comparing in-phase and/or quadrature phase baseband signals with pre-determined threshold limits that indicate that the in-phase and quadrature phase signals have exceeded the normal signal trajectory of an unimpaired signal. Corrupted symbols may also be detected by determining that the laser has been clipped. Corrupted symbols are marked for erasure prior to decoding and error correction. Erasure of corrupted signals increases the error correction capabilities of the decoder circuit.
14 Citations
28 Claims
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1. A receiver that receives a data stream of modulated data symbols that have been encoded with a linear block code comprising:
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a comparator that compares said data symbols with at least one limit that indicates impairment of said data symbols; an output control signal generated by said comparator that marks said corrupt data symbols in said data stream; and a decoder that is connected to said comparator that receives said output control signal and erases said corrupt data symbols that are marked by said output control signal prior to performing error corrections so as to increase error correction capabilities of said decoder. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A communication system for transmitting and receiving a stream of data comprising:
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an encoder that encodes said stream of data into data symbols using a linear block code; a transmitter that transmits said data symbols over an optical communication link using lasers; a clipping detector that compares said data symbols with at least one threshold value that is determined in accordance with clipping levels of said lasers, and generates a clipping control signal that marks said corrupted data symbols; a decoder that receives said clipping control signal that erases said corrupted data symbols in response to said clipping control signal prior to performing error correction to increase correction capabilities of said decoder. - View Dependent Claims (8, 9)
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10. A receiver for receiving a data stream of data symbols that have been encoded with a linear block code comprising:
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a complex demodulator that demodulates said data symbols to produce an in-phase component and a quadrature phase component; detectors that detect if said in-phase component and said quadrature phase component exceed thresholds that indicate in-band impairment of said data symbols and generate control signals that identify data symbols for erasure selected from the group consisting of data symbols that have;
in-phase components that exceed said predetermined thresholds, and quadrature phase components that exceed said predetermined thresholds;a decoder that erases said data symbols that have been identified by said control signals prior to decoding by said decoder to increase data correction capabilities of said decoder. - View Dependent Claims (11, 12, 13, 14)
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15. A method of increasing error correction capabilities of a decoder that decodes and corrects linear block encoded symbols comprising:
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transmitting said linear block encoded symbols in a composite signal through an optical transmission line using lasers; comparing a composite signal level of said composite signal with at least one limit to identify corrupt data symbols in said data stream, said limit corresponding to at least one of the group consisting of;
a saturation limit of said lasers and a threshold limit of said lasers;generating a control signal that marks said corrupt data symbols; erasing said corrupt data symbols that have been marked by said control signal; decoding said data stream after said corrupt data symbols have been erased from said data stream to increase said error correction capabilities of said decoder. - View Dependent Claims (16, 17)
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18. A method of increasing error correction capabilities of a decoder that decodes and corrects linear block encoded symbols comprising:
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converting an analog composite signal containing said linear block encoded symbols to a digital composite signal containing said linear block encoded symbols using an analog to digital converter; comparing said digital composite signal with at least one limit to identify corrupt data symbols in said digital composite signal containing said linear block encoded symbols, said limit corresponding to clipping levels of said analog to digital converter; generating a control signal that marks said corrupt data symbols; erasing said corrupt data symbols that have been marked by said control signal; decoding said digital composite signal containing said linear block encoded symbols after said corrupt data symbols have been erased from said digital composite signal to increase said error correction capabilities of said decoder. - View Dependent Claims (19, 20, 21)
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22. A method of increasing error correction capabilities of a receiver that receives a data stream of data symbols that have been encoded with a linear block code comprising:
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demodulating said data stream of said data symbols such that said data symbols have an in-phase component and a quadrature phase component; detecting if said in-phase component exceeds in-phase limits that indicate an in-band impairment of said in-phase component; detecting if said quadrature phase component exceeds quadrature phase limits that indicate in-band impairment of said quadrature phase component; generating a control signal that identifies corrupt data symbols for erasure that have an in-phase component that exceeds said in-phase limits or a quadrature phase component that exceeds said quadrature phase limits; erasing said corrupt data symbols that have been identified by said control signal; decoding said data symbols after said corrupt data symbols that have been identified by said control signal have been erased, so as to increase data correction capabilities of said receiver. - View Dependent Claims (23, 24, 25, 26, 27, 28)
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Specification