Low density parity check decoder for irregular LDPC codes
AssigneeThe Texas A&M University System
InventorsKiran Kumar Gunnam, Gwan S. Choi
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Abstract
A method and system for decoding low density parity check (“LDPC”) codes. An LDPC decoder includes a control unit that controls decoder processing, the control unit causing the decoder to process the blocks of a low density parity check (“LDPC”) matrix out of order. A decoder embodiment may process the layers of the LDPC matrix out of order and/or perform partial state processing on out of order blocks of the LDPC matrix and/or generate R messages out of order.
Claims22
A low density parity check (LDPC) code decoder, comprising:
- a control unit that controls decoder processing, the control unit configured to cause the decoder to process blocks of an LDPC matrix in a first sequence, and to compute R messages for the blocks in a second sequence that is different from the first sequence, wherein the first sequence specifies a first set of blocks of a given layer to be processed at a given time and a second set of blocks of the given layer to be processed after the first set of blocks;
- wherein the first set specifies only blocks of the given layer that are not dependent on a result of a previously processed layer and the second set specifies blocks of the given layer that are dependent on a result of the previously processed layer.
A method for decoding a low density parity check (LDPC) code, comprising:
- processing blocks of an LDPC matrix in a first sequence;
- computing R messages for the blocks in a second sequence that is different from the first sequence;
- specifying, via the first sequence, a first set of blocks of a given layer to be processed at a given time and a second set of blocks of the given layer to be processed after the first set of blocks;
- wherein the first set specifies only blocks of the given layer that are not dependent on a result of a previously processed layer and the second set specifies blocks of the given layer that are dependent on a result of the previously processed layer.
A low density parity check (LDPC) code decoder, comprising:
- a control unit that controls decoder processing, the control unit configured to cause the decoder to:
- process blocks of an LDPC matrix out of order;
- and
- process each block of the matrix in processing substeps comprising:
- an R new update substep that produces an R new message for a block of a different layer of the matrix from a layer containing a block currently being processed;
- an R old update substep that selects an R old message for a layer of the matrix currently being processed;
- a P message substep that generates updated P messages;
- and
- a Q message substep that computes variable node messages (Qmessages);
- a first permuter that permutes a P message, wherein the permuter permutes the P message by the difference of the permutation of a block currently being processed and the permutation of a block previously processed;
- wherein the block currently being processed and the block previously processed are in a same block column.
A method for decoding a low density parity check (LDPC) code, comprising:
- processing blocks of an LDPC matrix out of order;
- and
- processing each block of the matrix in processing substeps comprising:
- an R new update substep that produces an R new message for a block of a different layer of the matrix from a layer containing a block currently being processed;
- an R old update substep that selects an R old message for a layer of the matrix currently being processed;
- a P message substep that generates updated P messages;
- and
- a Q message substep that computes variable node messages (Q messages);
- permuting a P message, wherein the permuting comprises permuting the P message by the difference of the permutation of a block currently being processed and the permutation of a block previously processed;
- wherein the block currently being processed and the block previously processed are in a same block column.
Dependencies are inferred from the claim text.