The subject of this paper is the design of lowdensity parity-check (LDPC) codes concatenated with a Gray mapped quaternary phase shift keying (QPSK) modulator for transmission over inter-symbol (ISI) channels. In particular, we will present several results considering important partial response channels (PRCs). Using an extrinsic information transfer (EXIT) chart-based analysis, we give insight...

We investigate the construction of quantum low-density parity-check (LDPC) codes from classical quasi-cyclic (QC) LDPC codes with girth greater than or equal to 6. We have shown that the classical codes in the generalized Calderbank-Shor-Steane (CSS) construction do not need to satisfy the dual-containing property as long as pre-shared entanglement is available to both sender and receiver. We c...

This paper presents a construction of low-density parity-check (LDPC) codes based on the incidence matrices of oval designs. The new LDPC codes have regular parity-check matrices and Tanner graphs free of 4-cycles. Like the finite geometry codes, the codes from oval designs have parity-check matrices with a large proportion of linearly dependent rows and can achieve significantly better minimum...

A turbo block code (TBC) technique for improving the performance of a multi-carrier code division multiple access (MC-CDMA) system in terms of bit error rate (BER) is proposed in this paper. The objective of this work is to develop a coding scheme that generates low BER code-words. By implementing a time domain TBC, designed using powerful low density parity check (LDPC) code, the BER performan...

In this paper we evaluate the performance of Gallager-B algorithm, used for decoding low-density paritycheck (LDPC) codes, under unreliable message computation. Our analysis is restricted to LDPC codes constructed from circular matrices (QC-LDPC codes). Using Monte Carlo simulation we investigate the effects of different code parameters on coding system performance, under a binary symmetric com...

In this paper, we propose to leverage the simple and explicit parity checks inherent in low-density parity-check (LDPC) codes to realize dominant error events detection without code rate penalty. This is enabled by enforcing a very weak constraint on LDPC code parity check matrix structure. Such a constraint can be readily satisfied by most structured LDPC codes ever studied in the open literat...

For an arbitrary (3,L) QC-LDPC code with a girth of twelve, a tight lower bound of the consecutive lengths is proposed. For an arbitrary length above the bound the resultant code necessarily has a girth of twelve, and for the length meeting the bound, the corresponding code inevitably has a girth smaller than twelve. The conclusion can play an important role in the proofs of the existence of la...

A low-density parity-check (LDPC) code is a linear error correcting code, and is used for transmitting message over a noisy transmission channel. A new class of error correcting codes called EG-LDPC (Euclidean Geometry-LDPC) codes and its encoder and decoder architectures for nanomemory applications is designed. EG-LDPC codes also have fault secure detection capability. One step majority logic ...

In this paper, a serial concatenation scheme and its iterative decoding algorithm between Low Density Parity Check codes (LDPC) and Reed-Solomon codes are proposed. For the decoder, the soft output values delivered by LDPC are used as reliability values to perform the Chase decoding of Reed-Solomon (RS) codes which return soft information to LDPC decoder. This approach presents an option scheme...

LDPC codes are one of the hottest topics in coding theory today. Originally invented in the early 1960’s, they have experienced an amazing comeback in the last few years. Unlike many other classes of codes LDPC codes are already equipped with very fast (probabilistic) encoding and decoding algorithms. The question is that of the design of the codes such that these algorithms can recover the ori...