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Weber J.H.,Technical University of Delft | Immink K.A.S.,Turing Inc. | Blackburn S.R.,Royal Holloway, University of London
IEEE Transactions on Information Theory | Year: 2016

The Pearson distance has been advocated for improving the error performance of noisy channels with unknown gain and offset. The Pearson distance can only fruitfully be used for sets of q-ary codewords, called Pearson codes, that satisfy specific properties. We will analyze constructions and properties of optimal Pearson codes. We will compare the redundancy of optimal Pearson codes with the redundancy of prior art T-constrained codes, which consist of q-ary sequences in which T pre-determined reference symbols appear at least once. In particular, it will be shown that for q ≤ 3, the two-constrained codes are optimal Pearson codes, while for q ≥ 4 these codes are not optimal. © 2015 IEEE. Source


Van Wijngaarden A.J.,Alcatel - Lucent | Schouhamer Immink K.A.,Turing Inc. | Schouhamer Immink K.A.,Institute for Experimental Mathematics | Schouhamer Immink K.A.,Data Storage Institute Singapore
IEEE Journal on Selected Areas in Communications | Year: 2010

The sequence replacement technique converts an input sequence into a constrained sequence in which a prescribed subsequence is forbidden to occur. Several coding algorithms are presented that use this technique for the construction of maximum run-length limited sequences. The proposed algorithms show how all forbidden subsequences can be successively or iteratively removed to obtain a constrained sequence and how special subsequences can be inserted at predefined positions in the constrained sequence to represent the indices of the positions where the forbidden subsequences were removed. Several modifications are presented to reduce the impact of transmission errors on the decoding operation, and schemes to provide error control are discussed as well. The proposed algorithms can be implemented efficiently, and the rates of the constructed codes are close to their theoretical maximum. As such, the proposed algorithms are of interest for storage systems and data networks. © 2010 IEEE. Source


Coding schemes for storage channels, such as optical recording and non-volatile memory (Flash), with unknown gain and offset are presented. In its simplest case, the coding schemes guarantee that a symbol with a minimum value (floor) and a symbol with a maximum (ceiling) value are always present in a codeword so that the detection system can estimate the momentary gain and the offset. The results of the computer simulations show the performance of the new coding and detection methods in the presence of additive noise. © The Institution of Engineering and Technology 2014. Source


Immink K.A.S.,Turing Inc. | Immink K.A.S.,Nanyang Technological University
IEEE Transactions on Information Theory | Year: 2012

In this paper, we will present coding techniques for the character-constrained channel, where information is conveyed using $q$-bit characters (nibbles), and where $w$ prescribed characters are disallowed. Using codes for the character-constrained channel, we present simple and systematic constructions of high-rate binary maximum runlength constrained codes. The new constructions have the virtue that large lookup tables for encoding and decoding are not required. We will compare the error propagation performance of codes based on the new construction with that of prior art codes. © 1963-2012 IEEE. Source


Immink K.A.S.,Turing Inc.
IEEE International Symposium on Information Theory - Proceedings | Year: 2013

We will present coding techniques for transmission and storage channels with unknown gain and/or offset. It will be shown that a codebook of length-n q-ary codewords, S, where all codewords in S have equal balance and energy show an intrinsic resistance against unknown gain and/or offset. Generating functions for evaluating the size of S will be presented. We will present an approximate expression for the code redundancy for asymptotically large values of n. © 2013 IEEE. Source

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