Low complexity decoding of finite geometry LDPC codes

We develop a new low complexity algorithm for decoding low-density parity-check (LDPC) codes. The developments are oriented specifically toward the low cost -yet effectivedecoding of (high rate) finite geometry LDPC codes. The decoding procedure updates the hard-decision received vector iteratively in search of a valid codeword in the vector space. Only one bit is changed in each iteration and the bit selection criterion combines the number of failed checks and the reliability of the received bits. Prior knowledge of the signal amplitude and noise power is not required. An optional mechanism to avoid infinite loops in the search is also proposed. Our studies show that the algorithm achieves an appealing performance versus complexity trade-off for finite geometry LDPC codes.