Algebraic LDPC Codes

Download or read book Algebraic LDPC Codes written by Keke Liu and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The algebraic low-density parity-check (LDPC) codes have received great attention in the practical applications to communication and data storage systems due to their fruitful structural properties and excellent overall performances. This dissertation investigates the following topics regarding the construction, analysis and decoding of the algebraic LDPC codes.The first contribution is a comprehensive rank analysis of the algebraic quasi-cyclic (QC) LDPC (QC-LDPC) codes constructed based on two arbitrary subsets of a finite field, which generalizes the rank analysis results in the previous literature. Also investigated is a flexible algebraic construction of QC-LDPC codes with large row redundancy based on field partitions. This construction results in a large class of binary regular QC-LDPC codes with flexible choices of rates and lengths that are shown to perform well over the additive white Gaussian noise (AWGN) channel. Secondly, to resolve the issue of decoder complexity caused by relatively high density of the parity-check matrices of algebraic LDPC codes, an effective revolving iterative decoding (RID) scheme is developed for algebraic cyclic and QC-LDPC codes. The proposed RID scheme significantly reduces the hardware implementation complexities. Also presented is a variation of the RID scheme, called merry-go-round (MGR) decoding scheme, which maintains the circulant permutation matrix (CPM) structure that is desirable for the hardware implementation but lost in the RID scheme, while preserving the merits of reducing decoder complexity. The proposed RID and MGR decoding schemes may enhance the applications of algebraic LDPC codes.Lastly, a general algebraic construction of QC-LDPC convolutional codes, also called spatially coupled (SC) QC-LDPC codes, is proposed. Simulation results show that the constructed algebraic SC-QC-LDPC codes can outperform their non-algebraic counterparts. Also investigated is the rate compatibility of the constructed SC-QC-LDPC codes using the regular puncturing scheme.