A runlength limited low-density parity-check coding scheme

Abstract

In this paper we propose a novel approach to modulation and error control coding. The idea is to completely eliminate a constrained code and, instead, impose the constraint by the deliberate introduction of bit errors before transmission. The redundancy that would have been used for imposing the constraint is used in our scheme to strengthen the error control code (ECC), in such a way that the ECC becomes capable of correcting both deliberate errors as well as channel errors that occurs during the detection. The proposed ECC-modulation scheme is based on iterative decoding of low-density parity-check codes (LDPC) and a runlength constraint.

Maximum a Posteriori Estimation With Vector Autoregressive Models for Digital Magnetic Recording Channels

“…Moreover, to satisfy the column weights are the another parity column with index is given as (26) If it is assumed that the symbols which gives in (23) are known nonzero values in advance, these parity diagonal symbols do not need to be transmitted and it is possible to except them from a codeword and they are considered to be dummy symbols in this array. Moreover, to give the condition of run-length limited constraint (RLL) [24]- [26] for this -ary code, the information symbols except these dummy symbols are encoded by the 64/65 (0,8) RLL encoder [27] for each codewords where defines the largest integer smaller than . This generated (0,8) constraint sequences are an inner codeword.…”

The Maximum A Posteriori Decoding Using Variational Bayes Methods for Digital Magnetic Recording Channels

“…1 shows the block diagram of the LDPC coded PR system with the proposed MAP decoding system. In this read/write system, a raw data sequence {ak} with bit rate fb is inputted into the modulation encoder which gives runlength limited (0, k) constraints (RLL (0, k)) for output sequences [15], [16]. The run-length limited sequence from this modulation encoder is transformed into the codeword sequence at the LDPC encoder.…”

Maximum a posteriori estimation using ARCH models and burst error correcting array codes for burst-erasure recording channels

“…Moreover, to give the condition of run-length limited constraint (RLL) [24]- [27] for this q-ary code, the information symbols are encoded by the k 0 /n 0 (0,k ) RLL encoder [28] for each M = qk/n 0 codewords where x defines the largest integer smaller than x. This generated (0,k ) constraint sequences are an inner codeword.…”