Method and apparatus for implementing a low density parity check code in a wireless system

• US 7,665,008 B2
• Filed: 03/31/2004
• Issued: 02/16/2010
• Est. Priority Date: 01/12/2004
• Status: Expired due to Fees

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Xia, Bo, Jacobsen, Eric A.
• Primary Examiner(s): Torres; Joseph D
• Application Number:
  US10/815,133
• Publication Number:
  US 20050166131A1
• Time in Patent Office: 2,148 Days
• Field of Search: 714/758, 714/781
• US Class Current: 714/758
• CPC Class Codes: H03M 13/036 Heuristic code construction methods, i.e. code construction or code search based on using trial-and-error
• CPC Class Codes: H03M 13/118 Parity check matrix structured for simplifying encoding, e.g. by having a triangular or an approximate triangular structure H03M13/1165 takes precedence
• CPC Class Codes: H03M 13/1194 Repeat-accumulate [RA] codes
• 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
• CPC Class Codes: H04L 1/0041 Arrangements at the transmitter end
• CPC Class Codes: H04L 1/0057 Block codes H04L1/0061, H04L1/0064 take precedence

Abstract

A low density parity check (LDPC) code is used within a wireless apparatus to perform forward error correction (FEC) coding. In at least embodiment of the invention, a (2000, 1600) bit-length LDPC code is used.

Claims

1. A wireless apparatus comprising:

a forward error correction (FEC) coder to encode digital data using a low density parity check (LDPC) code, said FEC coder including;

a computer readable storage medium storing at least a first portion of a parity check matrix, wherein said first portion of said parity check matrix includes at least half of said parity check matrix;

a matrix multiplication unit to multiply input data by a transpose of said first portion of said parity check matrix to generate modified data;

a differential encoder to differentially encode said modified data to generate coded data; and

a concatenation unit to concatenate the input data and the coded data to form a code word; and

a wireless transmitter to transmit a wireless signal that includes said code word;

wherein said parity check matrix, in list file form, is substantially as follows;

2. The wireless apparatus of claim 1, wherein:

said wireless signal is an orthogonal frequency division multiplexing (OFDM) signal.

3. The wireless apparatus of claim 1, further comprising:

a mapper, between said FEC coder and said wireless transmitter, to map said code word based on a predetermined modulation scheme; and

an inverse discrete Fourier transform unit to convert mapped data from a frequency domain representation to a time domain representation.

4. The wireless apparatus of claim 1, wherein:

said first portion of said parity check matrix is a portion that includes columns of said parity check matrix having a column weight of 4.

5. The wireless apparatus of claim 1, wherein:

said first portion of said parity check matrix includes said entire parity check matrix.

6. The wireless apparatus of claim 1, wherein:

said LDPC code is a (2000,

     1600) LDPC code.

7. The wireless apparatus of claim 1, wherein:

said wireless apparatus is a wireless user device for use in a wireless network.

8. The wireless apparatus of claim 1, wherein:

said wireless apparatus is a wireless access point.

9. The wireless apparatus of claim 1, wherein:

said wireless apparatus is a wireless network interface module.

10. The wireless apparatus of claim 1, wherein:

said wireless apparatus is an integrated circuit.

11. A computer implemented method comprising:

accessing a computer readable storage medium storing a representation of at least a first portion of a parity check matrix, wherein said said first portion of said parity check matrix includes at least half of said parity check matrix;

matrix multiplying input data by a transpose of said first portion of said parity check matrix;

processing a result of said matrix multiplication using differential encoding to generate coded data;

concatenating said input data and said coded data to form a code word; and

generating and transmitting a wireless signal that includes said code word;

wherein said parity check matrix, in list file form, is substantially as follows;

12. The method of claim 11, wherein:

said wireless signal is an orthogonal frequency division multiplexing (OFDM) signal.

13. The method of claim 11, wherein:

said first portion of said parity check matrix is a portion that includes columns of said parity check matrix having a column weight of 4.

14. The method of claim 11, wherein:

said parity check matrix defines a (2000,

     1600) LDPC code.

15. The method of claim 11, wherein:

generating and transmitting a wireless signal includes mapping said code word into modulation symbols and processing said modulation symbols using an inverse discrete Fourier transform.

16. A system comprising:

a forward error correction (FEC) coder to encode digital data using a low density parity check (LDPC) code, said FEC coder including;

a computer readable storage medium storing at least a first portion of a parity check matrix, wherein said first portion of said parity check matrix includes at least half of said parity check matrix;

a matrix multiplication unit to multiply input data by a transpose of said first portion of said parity check matrix to generate modified data;

a differential encoder to differentially encode said modified data to generate coded data; and

a concatenation unit to concatenate the input data and the coded data to form a code word;

a wireless transmitter to transmit a wireless signal that includes said code word; and

at least one dipole antenna coupled to said wireless transmitter to facilitate transmission of said wireless signal;

wherein said parity check matrix, in list file form, is substantially as follows;

17. The system of claim 16, wherein:

said wireless signal is an orthogonal frequency division multiplexing (OFDM) signal.

18. The system of claim 16, wherein:

said first portion of said parity check matrix is a portion that includes columns of said parity check matrix having a column weight of 4.

19. An article comprising a computer readable storage medium having instructions stored thereon that, when executed by a computing platform, operate to:

matrix multiply input data by a transpose of a first portion of a parity check matrix, wherein said first portion of said parity check matrix includes at least half of said parity check matrix;

process a result of said matrix multiplication using differential encoding to generate coded data;

concatenate said input data and said coded data to form a code word; and

generate and transmit a wireless signal that includes said code word;

wherein said parity check matrix, in list file form, is substantially as follows;

20. The article of claim 19, wherein:

said wireless signal is an orthogonal frequency division multiplexing (OFDM) signal.

21. The article of claim 19, wherein said instructions, when executed by the computing platform, further operate to:

access a storage medium having at least a portion of said parity check matrix stored thereon before matrix multiplying.

22. The article of claim 19, wherein:

said first portion of said parity check matrix is a portion that includes columns of said parity check matrix having a column weight of 4.

23. The article of claim 19, wherein:

said parity check matrix defines a (2000,

     1600) LDPC code.