J4 ›› 2010, Vol. 37 ›› Issue (4): 700-704.doi: 10.3969/j.issn.1001-2400.2010.04.021

• Original Articles • Previous Articles     Next Articles

Improved cycle elimination algorithm for construction of QC-LDPC codes

CUI Jun-yun;BAI Bao-ming;GUO Xu-dong   

  1. (State Key Lab. of Integrated Service Networks, Xidian Univ., Xi'an  710071, China)
  • Received:2009-06-24 Online:2010-08-20 Published:2010-10-11
  • Contact: CUI Jun-yun E-mail:02044027@163.com

Abstract:

A novel construction algorithm for quasi-cyclic low-density parity-check codes is proposed, with which we can obtain the improved girth of the corresponding Tanner graph by generalizing Yang et al.'s constraint for any cycle detected in the base matrix to detect and break the cycles in the parity check matrix. Compared with the existing cycle elimination (CE) algorithm, a better error performance can be achieved and cycle-8 free. Simulation results show that the proposed algorithm for constructing the irregular LDPC code of rate 1/2 achieves the performance of codeword error rate of 2×10-6 at Eb/N0=1.5dB with 80 iterations by the belief-propagation decoding algorithm.

Key words: girth, quasi-cyclic low-density parity-check (QC-LDPC) codes, cycle elimination