Systems and methods for processing LDPC codes with different circulant sizes

• US 9,548,759 B1
• Filed: 11/26/2014
• Issued: 01/17/2017
• Est. Priority Date: 11/26/2013
• Status: Active Grant

• Current Assignee: Marvell Asia Pte Limited (Marvell Technology Group Limited)
• Original Assignee: Marvell International Limited (Marvell Technology Group Limited)
• Inventors: Rad, Farshid Rafiee
• Primary Examiner(s): Alphonse, Fritz
• Application Number:
  US14/554,845
• Time in Patent Office: 783 Days
• Field of Search: 714/780, 714/752, 714/755, 714/810, 714/776, 714/774, 714/794
• US Class Current: 1/1
• CPC Class Codes: H03M 13/1137 Partly parallel processing, i.e. sub-blocks or sub-groups of nodes being processed in parallel
• CPC Class Codes: H03M 13/114 Shuffled, staggered, layered or turbo decoding schedules
• CPC Class Codes: H03M 13/116 Quasi-cyclic LDPC [QC-LDPC] codes, i.e. the parity-check matrix being composed of permutation or circulant sub-matrices
• CPC Class Codes: H03M 13/6516 Support of multiple code parameters, e.g. generalized Reed-Solomon decoder for a variety of generator polynomials or Galois fields

Abstract

Systems and methods are provided for decoding low density parity check (LDPC) codes with different circulant sizes using common decoding circuitry. The systems and methods include receiving a plurality of codewords corresponding to an LDPC code and determining a circulant size associated with the plurality of received codewords. In response to determining the circulant size associated with the plurality of received codewords, the systems and methods partition processing resources of the common decoding circuitry into a plurality of cells based on the determined circulant size and processing the plurality of received codewords simultaneously using the plurality of cells.

Claims

1. A method for decoding low density parity check (LDPC) codes with different circulant sizes using common decoding circuitry, the method comprising:

receiving a plurality of codewords;

determining, using control circuitry, one of a first mode of operation and a second mode of operation based on a circulant size associated with the plurality of received codewords, wherein;

the first mode of operation is associated with receiving a plurality of codewords of a first LDPC code and

the second mode of operation is associated with receiving a single codeword of a second LDPC code;

in response to determining the circulant size associated with the plurality of received codewords, partitioning processing resources of the common decoding circuitry into a plurality of cells based on the determined circulant size; and

processing the plurality of received codewords using the plurality of cells.

2. The method of claim 1, wherein a number of cells in the plurality of cells is selected to be equal to a number of codewords in the plurality of received codewords.

3. The method of claim 1, wherein processing the plurality of received codewords comprises processing the plurality of codewords using an iterative message-passing algorithm.

4. The method of claim 1, wherein the plurality of codewords corresponds to the first LDPC code, the plurality of codewords is of a first type, and the method further comprises:

receiving a codeword of a second type corresponding to the second LDPC code;

determining a circulant size associated with the received codeword of the second type, wherein the circulant size associated with the received codeword of the second type is larger than the circulant size associated with the plurality of received codewords of the first type;

in response to determining the circulant size associated with the received codeword of the second type, processing the received codeword of the second type jointly using the partitioned processing resources of the common decoding circuitry.

5. The method of claim 1, wherein the first LDPC code is associated with a code rate of 75% and the second LDPC code is associated with a code rate of 85%.

6. The method of claim 1, wherein the first LDPC code is associated with a circulant size that is smaller than a circulant size associated with the second LDPC code.

7. The method of claim 1, wherein processing the plurality of codewords comprises:

processing the plurality of codewords simultaneously using the plurality of cells to obtain a plurality of processed codewords; and

circularly shifting the plurality of processed codewords using a circular shifter based on the determined circulant size associated with the plurality of codewords.

8. The method of claim 1, wherein the circulant size associated with the plurality of codewords is determined based on a control signal.

9. The method of claim 1, wherein processing the plurality of codewords comprises:

determining whether an early termination criterion is satisfied, wherein the early termination criterion is based on the circulant size associated with the plurality of codewords.

10. A system for decoding low density parity check (LDPC) codes with different circulant sizes, the system comprising:

common decoding circuitry configured to process a plurality of codewords; and

control circuitry configured to;

receive the plurality of codewords;

determine one of a first mode of operation and a second mode of operation based on a circulant size associated with the plurality of received codewords, wherein;

the first mode of operation is associated with receiving a plurality of codewords associated with a first LDPC code and

the second mode of operation is associated with receiving a single codeword associated with a second LDPC code;

partition processing resources of the common decoding circuitry into a plurality of cells based on the determined circulant size, in response to determining the circulant size associated with the plurality of received codewords; and

cause the common decoding circuitry to process the plurality of received codewords using the plurality of cells.

11. The system of claim 10, wherein a number of cells in the plurality of cells is selected to be equal to a number of codewords in the plurality of received codewords.

12. The system of claim 10, wherein the common decoding circuitry is further configured to process the plurality of codewords using an iterative message-passing algorithm.

13. The system of claim 10, wherein the plurality of codewords corresponds to the first LDPC code, the plurality of codewords is of a first type, and the control circuitry is further configured to:

receive a codeword of a second type corresponding to the second LDPC code;

determine a circulant size associated with the received codeword of the second type, wherein the circulant size associated with the received codeword of the second type is larger than the circulant size associated with the plurality of received codewords of the first type; and

cause the common decoding circuitry to process the received codeword of the second type jointly using the partitioned processing resources of the common decoding circuitry, in response to determining the circulant size associated with the received codeword of the second type.

14. The system of claim 10, wherein the first LDPC code is associated with a code rate of 75% and the second LDPC code is associated with a code rate of 85%.

15. The system of claim 10, wherein the first LDPC code is associated with a circulant size that is smaller than a circulant size associated with the second LDPC code.

16. The system of claim 10, wherein the common decoding circuitry is further configured to process the plurality of codewords by:

processing the plurality of codewords simultaneously using the plurality of cells to obtain a plurality of processed codewords; and

circularly shifting the plurality of processed codewords using a circular shifter based on the determined circulant size associated with the plurality of codewords.

17. The system of claim 10, wherein the circulant size associated with the plurality of codewords is determined based on a control signal.

18. The system of claim 10, wherein the control circuitry is further configured to:

determine whether an early termination criterion is satisfied, wherein the early termination criterion is based on the circulant size associated with the plurality of codewords.

19. A method for decoding low density parity check (LDPC) codes with different circulant sizes using common decoding circuitry, the method comprising:

receiving a plurality of codewords;

determining, using control circuitry, a circulant size associated with the plurality of received codewords;

in response to determining the circulant size associated with the plurality of received codewords, partitioning processing resources of the common decoding circuitry into a plurality of cells based on the determined circulant size;

processing the plurality of codewords concurrently using the plurality of cells to obtain a plurality of processed codewords; and

circularly shifting the plurality of processed codewords using a circular shifter based on the determined circulant size associated with the plurality of codewords.

20. A system for decoding low density parity check (LDPC) codes with different circulant sizes, the system comprising:

common decoding circuitry configured to process a plurality of codewords; and

control circuitry configured to;

receive the plurality of codewords;

determine a circulant size associated with the plurality of received codewords;

partition processing resources of the common decoding circuitry into a plurality of cells based on the determined circulant size, in response to determining the circulant size associated with the plurality of received codewords;

process the plurality of codewords concurrently using the plurality of cells to obtain a plurality of processed codewords; and

circularly shift the plurality of processed codewords using a circular shifter based on the determined circulant size associated with the plurality of codewords.