Muhammad I Chaudhry

US Patent:

8024641, Sep 20, 2011

Filed:

Feb 12, 2010

Appl. No.:

12/704850

Inventors:

Michael Livshitz - Rockville MD, US
Aleksandar Purkovic - Potomac MD, US
Nina Burns - Columbia MD, US
Sergey Sukhobok - Rockville MD, US
Muhammad Chaudhry - Gaithersburg MD, US

Assignee:

Nortel Networks Limited - St. Laurent
Nortel Networks Inc. - Nashville TN

International Classification:

H03M 13/00

US Classification:

714758, 714752

Abstract:

A method for constructing a low-density parity-check (LDPC) code using a structured base parity check matrix with permutation matrix, pseudo-permutation matrix, or zero matrix as constituent sub-matrices; and expanding the structured base parity check matrix into an expanded parity check matrix. A method for constructing a LDPC code using a structured base parity check matrix H=[H|H], His the data portion, and His the parity portion of the parity check matrix; the parity portion of the structured base parity check matrix is such so that when expanded, an inverse of the parity portion of the expanded parity check matrix is sparse; and expanding the structured base parity check matrix into an expanded parity check matrix. A method for encoding variable sized data by using the expanded LDPC code; and applying shortening, puncturing.

US Patent:

8301975, Oct 30, 2012

Filed:

Jun 9, 2011

Appl. No.:

13/156942

Inventors:

Michael Livshitz - Rockville MD, US
Aleksandar Purkovic - Potomac MD, US
Nina Burns - Columbia MD, US
Sergey Sukhobok - Rockville MD, US
Muhammad Chaudhry - Gaithersburg MD, US

Assignee:

Research In Motion Limited - Waterloo, Ontario

International Classification:

H03M 13/00

US Classification:

714758, 714752

Abstract:

A method for constructing a low-density parity-check (LDPC) code using a structured base parity check matrix with permutation matrix, pseudo-permutation matrix, or zero matrix as constituent sub-matrices; and expanding the structured base parity check matrix into an expanded parity check matrix. A method for constructing a LDPC code using a structured base parity check matrix H=[H|H], His the data portion, and His the parity portion of the parity check matrix; the parity portion of the structured base parity check matrix is such so that when expanded, an inverse of the parity portion of the expanded parity check matrix is sparse; and expanding the structured base parity check matrix into an expanded parity check matrix. A method for encoding variable sized data by using the expanded LDPC code; and applying shortening, puncturing.

US Patent:

7996746, Aug 9, 2011

Filed:

Oct 12, 2005

Appl. No.:

11/665171

Inventors:

Michael Livshitz - Rockville MD, US
Aleksandar Purkovic - Potomac MD, US
Nina Burns - Columbia MD, US
Sergey Sukhobok - Rockville MD, US
Muhammad Chaudhry - Gaithersburg MD, US

Assignee:

Nortel Networks Limited - St. Laurent
Nortel Networks Inc. - Nashville TN

International Classification:

H03M 13/00

US Classification:

714758, 714752

Abstract:

A method for constructing a low-density parity-check (LDPC) code using a structured base parity check matrix with permutation matrix, pseudo-permutation matrix, or zero matrix as constituent sub-matrices; and expanding the structured base parity check matrix into an expanded parity check matrix. A method for constructing a LDPC code using a structured base parity check matrix H=[H|H], His the data portion, and His the parity portion of the parity check matrix; the parity portion of the structured base parity check matrix is such so that when expanded, an inverse of the parity portion of the expanded parity check matrix is sparse; and expanding the structured base parity check matrix into an expanded parity check matrix. A method for encoding variable sized data by using the expanded LDPC code; and applying shortening, puncturing.

US Patent:

20130013983, Jan 10, 2013

Filed:

Sep 14, 2012

Appl. No.:

13/619420

Inventors:

Michael Livshitz - Rockville MD, US
Aleksandar Purkovic - Potomac MD, US
Nina Burns - Columbia MD, US
Sergey Sukhobok - Rockville MD, US
Muhammad Chaudhry - Gaithersburg MD, US

International Classification:

H03M 13/05

US Classification:

714776, 714E11032

Abstract:

Example methods are disclosed for encoding variable sized data using a low-density parity-check (LDPC) code, and transporting the encoded variable sized data in modulated symbols. Example methods involve calculating a minimum number of modulated symbols capable of transmitting a data packet; selecting a codeword size suitable for transmitting the data packet; calculating a number of shortening Nbits; and calculating a number of puncturing Nbits, to thereby produce a shortened and punctured expanded parity check matrix for transmitting the data packet.