Izvorni znanstveni članak
https://doi.org/10.24138/jcomss.v2i3.283
Design of LDPC Codes: A Survey and New Results
Gianluigi Liva
; University of Bologna
Shumei Song
; University of California at Davis
Lan Lan
; University of California at Davis
Yifei Zhang
; University of Arizona, U.S.A
Shu Lin
; University of California at Davis
William E. Ryan
; University of Arizona, U.S.A
Sažetak
This survey paper provides fundamentals in the design of LDPC codes. To provide a target for the code designer, we first summarize the EXIT chart technique for determining (near-)optimal degree distributions for LDPC code ensembles. We also demonstrate the simplicity of representing codes by protographs and how this naturally leads to quasi-cyclic LDPC codes. The EXIT chart technique is then extended to the special case of protograph-based LDPC codes. Next, we present several design approaches for LDPC codes which incorporate one or more accumulators, including quasi-cyclic accumulatorbased codes. The second half the paper then surveys several algebraic LDPC code design techniques. First, codes based on finite geometries are discussed and then codes whose designs are based on Reed-Solomon codes are covered. The algebraic designs lead to cyclic, quasi-cyclic, and structured codes. The masking technique for converting regular quasi-cyclic LDPC codes to irregular codes is also presented. Some of these results and codes have not been presented elsewhere. The paper focuses on the binary-input AWGN channel (BI-AWGNC). However, as discussed in the paper, good BI-AWGNC codes tend to be universally good across many channels. Alternatively, the reader may treat this paper as a starting point for extensions to more advanced channels. The paper concludes with a brief discussion of open problems.
Ključne riječi
Hrčak ID:
180850
URI
Datum izdavanja:
22.9.2006.
Posjeta: 5.151 *