Low complexity LDCP decoding
AssigneeQuantenna Communications, Inc.
InventorsFredrik Brannstrom, Andrea Goldsmith
Life of this patent
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Abstract
A technique for low-density parity-check (LDPC) coding involves utilizing a fixed point implementation in order to reduce or eliminate reliance on floating point operations. The fixed point implementation can be used to calculate check node extrinsic L-value as part of an LDPC decoder in an LDPC system. The technique can include one or more of linear approximations, offset approximations, and node-limiting approximation. A system constructed according to the technique implements one or more of linear approximations, offset approximations, and node-limiting approximation.
Claims21
A method comprising:
- receiving a codeword;
- repeating until no new values for an extrinsic L-value computation (ELC) parameter are called for in association with decoding the codeword:
- selecting an ELC parameter value from a plurality of values based upon a variable;
- computing extrinsic L-values for low-density parity-check (LDPC) check nodes and variable nodes using the ELC parameter for one or more iterations;
- calculating a posteriori probability (APP) L-values for the codeword;
- extracting information bits associated with the decoded codeword;
- forwarding the information bits.
A system comprising:
- a codeword buffer;
- an offset engine;
- a low density parity-check (LDPC) decoding engine coupled to the codeword buffer and the offset engine;
- a data buffer coupled to the LDPC decoding engine;
- wherein, in operation,
- the codeword buffer contains a codeword;
- the offset engine provides a bias parameter, B, where 0≦B≦ln(dc−1) to the LDPC decoding engine;
- the LDPC decoding engine computes extrinsic L-values for low-density parity-check (LDPC) check nodes and variable nodes using the bias parameter;
- the LDPC decoding engine calculates a posteriori probability (APP) L-values for the codeword and extracts information bits associated with the decoded codeword;
- the data buffer has the information bits associated with the decoded codeword.
A system comprising:
- a codeword buffer;
- an approximation engine;
- a low density parity-check (LDPC) decoding engine coupled to the codeword buffer and the approximation engine;
- a data buffer coupled to the LDPC decoding engine;
- wherein, in operation,
- the codeword buffer contains a codeword;
- the offset engine provides a node-limiting parameter (Q) to the LDPC decoding engine;
- the LDPC decoding engine computes extrinsic L-values for check nodes and variable nodes, excluding a set of nodes in accordance with the node-limiting parameter;
- the LDPC decoding engine calculates a posteriori probability (APP) L-values for the codeword and extracts information bits associated with the decoded codeword;
- the data buffer has the information bits associated with the decoded codeword.
Dependencies are inferred from the claim text.