A Greedy Search Based Method with Optimized Lower Bound for QC-LDPC Codes

Autonomous decentralized system is need of the dynamically varying society. Various autonomous decentralized systems architecture proposed and deployed, use of IEEE 802.11n/ac (Wi-Fi) and IEEE 802.16e (Wi-max) standards for surveillance purposes in different geographical region. These standards use LDPC codes as a channel code having better error correcting performance. This article deals with a construction of less computational complexity method for constructing exponent matrix (3, K) having girth 8, 10, and 12 of quasi-cyclic low-density parity-check (QC-LDPC) codes. In this method, we first generate a base matrix and then the same matrix is further used for expanding till desired size of the exponent matrix. The construction of code deals with the generation of base matrix by a simple algorithm for girth 8, 10, and 12. Our method is flexible for any block-column length K. Finally, a new method is given with less computational complexity with optimized CPM size.