Exact ber reporting in the presence of CRC termination
AssigneeSK hynix Inc.
InventorsMeysam Asadi, Fan Zhang, Haobo Wang
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Abstract
A method and system for LDPC decoding method. In the method and system, an LDPC codeword is decoded using a quasi-cyclic matrix. A first message for variable nodes in a circulant column of the quasi-cyclic matrix and a second message for check nodes belonging to the circulant column are computed. Parity and syndrome are computed using the computed first and second messages. A bit error rate is calculated for both a first mode with no error in a parity portion of a codeword and a second mode with errors in the parity portion of the codeword.
Claims20
An LDPC decoding method comprising:
- decoding an LDPC codeword into a user portion and a parity portion using a quasi-cyclic matrix, which includes multiple circulant columns;
- wherein the decoding at a particular circulant column of the multiple circulant columns includes:
- computing a message for variable nodes in the particular circulant column and a message for check nodes belonging to a particular circulant row;
- computing cyclic redundancy check (CRC) parity and a syndrome using the computed messages;
- determining a first mode and a second mode, based on the CRC parity and the syndrome;
- and
- calculating a bit error rate (BER) at both the first mode and the second mode,
- wherein the first mode corresponds to when the CRC parity is valid and the syndrome has a particular value, which corresponds to that the user portion of the LDPC codeword has been decoded correctly, and there is no error in the parity portion of the LDPC codeword, and
- wherein the second mode corresponds to when the CRC parity is valid and the syndrome has not the particular value, which corresponds to that the user portion of the LDPC codeword has been decoded correctly, and there are errors in the parity portion of the LDPC codeword.
A system for LDPC decoding, comprising:
- a data source;
- and
- a controller configured to perform LDPC decoding of data bit information from the data source,
- wherein the controller is configured to:
- decode an LDPC codeword using a quasi-cyclic matrix into a user portion and a parity portion;
- compute a first message for variable nodes in a circulant column of the quasi-cyclic matrix and a second message for check nodes belonging to the circulant column;
- compute cyclic redundancy check (CRC) parity and a syndrome using the computed first and second messages;
- determine a first mode and a second mode, based on the CRC parity and the syndrome;
- and
- calculate a bit error rate (BER) for both the first mode and the second mode,
- wherein the first mode corresponds to when the CRC parity is valid and the syndrome has a particular value, which corresponds to that the user portion of the LDPC codeword has been decoded correctly, and there is no error in the parity portion of the LDPC codeword, and
- wherein the second mode corresponds to when the CRC parity is valid and the syndrome has not the particular value, which corresponds to that the user portion of the LDPC codeword has been decoded correctly, and there are errors in the parity portion of the LDPC codeword.
Dependencies are inferred from the claim text.