Iterative metric updating when decoding LDPC (low density parity check) coded signals and LDPC coded modulation signals
First Claim
1. A method for operating a decoder to decode an LDPC (Low Density Parity Check) coded signal, the method comprising:
- employing a bit node processing module and a check node processing module to perform bit node processing and check node processing, respectively, during a first decoding iteration in which the bit node processing employs a first plurality of bit metrics and the decoder generates a first soft estimate of a bit within the LDPC coded signal, wherein the plurality of bit metrics corresponds to a bit within the LDPC coded signal;
updating the first plurality of bit metrics using the first soft estimate thereby generating a second plurality of bit metrics; and
employing the bit node processing module and the check node processing module to perform bit node processing and check node processing, respectively, during a second decoding iteration in which the bit node processing employs the second plurality of bit metrics and the decoder generates a second soft estimate of the bit within the LDPC coded signal.
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Abstract
Iterative metric updating when decoding LDPC (Low Density Parity Check) coded signals and LDPC coded modulation signals. A novel approach is presented for updating the bit metrics employed when performing iterative decoding of LDPC coded signals. This bit metric updating is also applicable to decoding of signals that have been generated using combined LDPC coding and modulation encoding to generate LDPC coded modulation signals. In addition, the bit metric updating is also extendible to decoding of LDPC variable code rate and/or variable modulation signals whose code rate and/or modulation may vary as frequently as on a symbol by symbol basis. By ensuring that the bit metrics are updated during the various iterations of the iterative decoding processing, a higher performance can be achieved than when the bit metrics remain as fixed values during the iterative decoding processing.
9 Citations
20 Claims
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1. A method for operating a decoder to decode an LDPC (Low Density Parity Check) coded signal, the method comprising:
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employing a bit node processing module and a check node processing module to perform bit node processing and check node processing, respectively, during a first decoding iteration in which the bit node processing employs a first plurality of bit metrics and the decoder generates a first soft estimate of a bit within the LDPC coded signal, wherein the plurality of bit metrics corresponds to a bit within the LDPC coded signal; updating the first plurality of bit metrics using the first soft estimate thereby generating a second plurality of bit metrics; and employing the bit node processing module and the check node processing module to perform bit node processing and check node processing, respectively, during a second decoding iteration in which the bit node processing employs the second plurality of bit metrics and the decoder generates a second soft estimate of the bit within the LDPC coded signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for operating a decoder to decode an LDPC (Low Density Parity Check) coded signal, the method comprising:
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during a first decoding iteration; employing a bit node processing module to perform bit node processing that involves using a first plurality of bit metrics when updating a first plurality of bit messages thereby generating a second plurality of bit edge messages, wherein the first plurality of bit metrics corresponds to a bit within the LDPC coded signal; employing a check node processing module to perform check node processing that involves using the second plurality of bit edge messages when updating a first plurality of check edge messages thereby generating a second plurality of check edge messages; and computing a first soft estimate of the bit within the LDPC coded signal using the second plurality of check edge messages; and during a second decoding iteration; updating the first plurality of bit metrics using the soft estimate thereby generating a second plurality of bit metrics; employing the bit node processing module to perform bit node processing that involves using the second plurality of bit metrics when updating the second plurality of bit messages thereby generating a third plurality of bit edge messages; employing the check node processing module to perform check node processing that involves using the third plurality of bit edge messages when updating the second plurality of check edge messages thereby generating a third plurality of check edge messages; and computing a second soft estimate of the bit within the LDPC coded signal using the third plurality of check edge messages. - View Dependent Claims (12, 13, 14, 15, 16)
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17. A decoder that is operable to decode an LDPC (Low Density Parity Check) coded signal, the decoder comprising:
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a bit node processing module that is operable to employ a first plurality of bit metrics when updating a first plurality of bit edge messages thereby generating a second plurality of bit edge messages, wherein the plurality of bit metrics corresponds to a bit within the LDPC coded signal; and a check node processing module that is operable to employ the second plurality of bit edge messages when updating a first plurality of check edge messages thereby generating a second plurality of check edge messages; and
wherein;the bit node processing module is operable to process the second plurality of check edge messages thereby generating a first soft estimate of the bit within the LDPC coded signal; the decoder is operable to update the first plurality of bit metrics using the first soft estimate thereby generating a second plurality of bit metrics; the bit node processing module is operable to employ the second plurality of bit metrics when updating the second plurality of bit edge messages thereby generating a third plurality of bit edge messages; the check node processing module is operable to employ the third plurality of bit edge messages when updating the second plurality of check edge messages thereby generating a third plurality of check edge messages; and the bit node processing module is operable to process the third plurality of check edge messages thereby generating a second soft estimate of the bit within the LDPC coded signal. - View Dependent Claims (18, 19, 20)
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Specification