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AFRICON Conference

作者： Djuric, Nikola Senk, Vojin Univ Novi Sad Fac Tech Sci Novi Sad 21000 Serbia

ISBN: (纸本)9781467359405

The constrained capability of maximum-transition-run (MTR) codes are well known in magnetic recording systems. Unfortunately, these codes possess just a modest error correcting ability and thus they have to be used in combination with proven and powerful error correcting codes. In modern, iterative decoding framework, two decoders exchange soft-information, in order to improve their decisions. Thus, the utilization of MTR codes in such framework requires some approaches for their soft-decision decoding. Recently, the MAP in LC method is proposed for such purpose, enabling propagation of soft-values through the MTR decoder. Substantial benefits have been noticed when the MAP in LC was used in a one-track MTR encoded E(2)PR4 magnetic recording channel. In this paper, performance and benefits of the MAP in LC, along with its two subversions, are considered over a multiple-track E(2)PR4 channel, encoded by the in-track MTR code. In case of the low-level inter-track interference, the subversion named as max-log MAP in LC shows nearly 0.85 dB of decoding gain, for BER = 10(-5), when 4/5 (2, 8) MTR code was used.

关键词： constrained coding MTR codes soft-decision decoding multiple-head recording

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constrained Rank Modulation Schemes

Constrained Rank Modulation Schemes

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IEEE Information Theory Workshop (ITW)

作者： Sala, Frederic Dolecek, Lara Univ Calif Los Angeles EE Dept Los Angeles CA 90095 USA

ISBN: (纸本)9781479913213

Rank modulation schemes for non-volatile memories (NVMs) represent information by the relative rankings of cell charge levels. This approach has several benefits;in particular, the scheme resolves the "write-asymmetry" limitation that NVMs suffer from. However, cell writing is still affected by a common NVM problem: inter-cell coupling, which can result in inadvertently increasing the charge level of neighboring cells. This is a potential source of error in the rank modulation scheme. In this paper, we explore the idea of constrained coding over permutations. These constraints minimize the impact of inter-cell coupling while still allowing the use of the rank modulation scheme. We study various constraints and their resulting rates, capacities, and other properties, and introduce an explicit constrained rank modulation code construction.

关键词： Rank modulation constrained coding coding for storage permutations sequences

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Bits Through Deterministic Relay Cascades With Half-Duplex Constraint

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IEEE TRANSACTIONS ON INFORMATION THEORY 2012年第1期58卷 369-381页

作者： Lutz, Tobias Hausl, Christoph Koetter, Ralf Tech Univ Munich Inst Commun Engn D-80290 Munich Germany

Consider a relay cascade, i.e., a network where a source node, a sink node and a certain number of intermediate source/relay nodes are arranged on a line and where adjacent node pairs are connected by error-free (q + 1)-ary pipes. Suppose the source and a subset of the relays wish to communicate independent information to the sink under the condition that each relay in the cascade is half-duplex constrained. A coding scheme is developed which transfers information by an information-dependent allocation of the transmission and reception slots of the relays. The coding scheme requires synchronization on the symbol level through a shared clock. The coding strategy achieves capacity for a single source. Numerical values for the capacity of cascades of various lengths are provided, and the capacities are significantly higher than the rates which are achievable with a predetermined time-sharing approach. If the cascade includes a source and a certain number of relays with their own information, the strategy achieves the cut-set bound when the rates of the relay sources fall below certain thresholds. For cascades composed of an infinite number of half-duplex constrained relays and a single source, we derive an explicit capacity expression. Remarkably, the capacity in bits/use for q = 1 is equal to the logarithm of the golden ratio, and the capacity for q = 2 is 1 bit/use.

关键词： Capacity capacity region constrained coding golden ratio half-duplex constraint method of types network coding relay networks timing

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coding for Inductively Coupled Channels

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IEEE TRANSACTIONS ON INFORMATION THEORY 2012年第8期58卷 5418-5436页

作者： Rosnes, Eirik Barbero, Angela I. Ytrehus, Oyvind Univ Bergen Dept Informat Selmer Ctr N-5020 Bergen Norway Univ Valladolid Dept Appl Math E-47011 Valladolid Spain

Inductive coupling is a technique wherein one device (the reader) induces an electrical current in another device (the tag), thereby providing not only power for the tag, but also a communication channel. In this paper, we focus exclusively on the reader-to-tag channel. The first part of this paper presents modulation codes that possess a high minimum and a high average power. This is important, since the tag gets its entire power from the received signal, and the information should be modulated in a way that maximizes the power transferred to the tag. The presented modulation codes compare favorably to codes used in radio frequency identification applications today. The second part of the paper describes modulation codes with some error-correcting capabilities. In fact, most errors in the reader-to-tag channel are due to incorrect timing. Here, we propose to model the timing errors in the reader-to-tag communication channel by a simple bit-shift channel, and we will present optimal (in the sense of maximizing the code rate for a given block length) single bit-shift error-correcting codes for this simple bit-shift channel that also have large average power.

关键词： Bit-shift channel constrained coding error-correcting codes inductive coupling modulation codes radio frequency identification (RFID) reader-to-tag channel synchronization errors

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MTR Decoding Employing MAP algorithm in Boolean Logic Circuits

MTR Decoding Employing MAP algorithm in Boolean Logic Circui...

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20th Telecommunications Forum

作者： Djuric, N. Senk, V. Univ Novi Sad Fac Tech Sci Novi Sad 21000 Serbia

ISBN: (纸本)9781467329842;9781467329835

Soft-decision decoding of maximum-transition-run (MTR) codes have been required in order to utilize those codes in modern data storage systems. The maximum a posteriori (MAP) algorithm, based on Bayesian algorithm, computing a posteriori information using set of valid MTR code-words, already has been presented. The MAP method proves as a valuable for the MTR decoding in several magnetic recording applications. In this paper, the MAP approach has been considered for utilization in basic Boolean logic circuits, trying to assemble a new low-complex and soft-decision MTR decoder. The proposed idea was considered with simple and well known rate 4/5 (2, k = 8) MTR code, without loosing in generality, over E(2)PR4 magnetic recording channel.

关键词： constrained coding MTR codes soft-decision

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The MAP Implementation in Logic Circuits for Soft-decision Decoding of MTR Codes

The MAP Implementation in Logic Circuits for Soft-decision D...

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6th UKSim/AMSS European Symposium on Computer Modeling and Simulation (EMS)

作者： Djuric, Nikola Senk, Vojin Univ Novi Sad Fac Tech Sci Trg D Obradovica 6 Novi Sad 21000 Serbia

ISBN: (纸本)9780769549262

Maximum a posteriori (MAP) algorithm and decoding with min-max approximations in Boolean logic circuits, had been independently considered as soft-decision decoding methods for maximum-transition-run (MTR) codes. These two approaches are confirmed as quite valuable, enabling MTR decoder to handle soft-values in framework of iterative decoding. In this paper further research of these methods has been made and novel idea of MAP algorithm utilization into logic circuits, of new MTR soft-decision decoder, is presented. The proposed concept is considered with simple and well know rate 4/5 (2, k = 8) MTR code over E(2)PR4 magnetic recording channel. The non-log and log MAP implementation results with equal performance, while max-log version results with 1.6 dB of coding gain, for BER = 10(-5)

关键词： MTR codes constrained coding soft-decision

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New Bounds on the Capacity of Multidimensional Run-Length Constraints

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IEEE TRANSACTIONS ON INFORMATION THEORY 2011年第7期57卷 4373-4382页

作者： Schwartz, Moshe Vardy, Alexander Ben Gurion Univ Negev Dept Elect & Comp Engn IL-84105 Beer Sheva Israel Univ Calif San Diego Dept Elect & Comp Engn Dept Comp Sci & Engn La Jolla CA 92093 USA Univ Calif San Diego Dept Math La Jolla CA 92093 USA

We examine the well-known problem of determining the capacity of multidimensional run-length-limited constrained systems. By recasting the problem, which is essentially a combinatorial counting problem, into a probabilistic setting, we are able to derive new lower and upper bounds on the capacity of (0, k)-RLL systems. These bounds are better than all previously-known analytical bounds for k >= 2, and are tight asymptotically. Thus, we settle the open question: what is the rate at which the capacity of (0, k)-RLL systems converges to 1 as k -> infinity? We also provide the first nontrivial upper bound on the capacity of general (d, k)-RLL systems.

关键词： constrained coding multidimensional constraints run-length limited coding 2-D constrained coding

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THE TRADEOFF FUNCTION FOR A CLASS OF RLL(d, k) CONSTRAINTS

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SIAM JOURNAL ON DISCRETE MATHEMATICS 2010年第4期24卷 1371-1398页

作者： Louidor, Erez Univ British Columbia Dept Math Vancouver BC V6K 2J7 Canada

A reverse concatenation coding scheme for storage systems in which the information is encoded first by a modulation (constraint) code and then by a systematic error-correcting code is considered. In this scheme, the output of the modulation coding stage has certain positions left "unconstrained" in the sense that any way of filling them with bits results in a sequence that satisfies the constraint. These positions are then used to store the parity-check bits of the error-correcting code so that the result is a valid constrained sequence. The tradeoff function defines the maximum overall rate of the encoding scheme for a given density of unconstrained positions. This function is determined for two families of run length limited (RLL) constraints: RLL(d, infinity) and RLL(d, 2d + 2). For RLL(d, 2d + 2), a curious dichotomy in the shape of the tradeoff function between different ranges of values of d is shown to exist.

关键词： constrained coding reverse concatenation tradeoff function run length limited Perron-Frobenius

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On the Capacity of the Precision-Resolution System

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IEEE TRANSACTIONS ON INFORMATION THEORY 2010年第3期56卷 1028-1037页

作者： Schwartz, Moshe Bruck, Jehoshua Ben Gurion Univ Negev Dept Elect & Comp Engn IL-84105 Beer Sheva Israel CALTECH Dept Elect Engn Pasadena CA 91125 USA

Arguably, the most prominent constrained system in storage applications is the (d, k)-run-length limited (RLL) system, where every binary sequence obeys the constraint that every two adjacent 1's are separated by at least d consecutive 0's and at most k consecutive 0's, namely, runs of 0's are length limited. The motivation for the RLL constraint arises mainly from the physical limitations of the read and write technologies in magnetic and optical storage systems. We revisit the rationale for the RLL system, reevaluate its relationship to the constraints of the physical media and propose a new framework that we call the Precision-Resolution (PR) system. Specifically, in the PR system there is a separation between the encoder constraints (which relate to the precision of writing information into the physical media) and the decoder constraints (which relate to its resolution, namely, the ability to distinguish between two different signals received by reading the physical media). We compute the capacity of a general PR system and compare it to the traditional RLL system.

关键词： Run-length limited (RLL) constrained coding capacity of constrained channels

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constrained coding for quasi-linear optical data transmission systems

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JOURNAL OF LIGHTWAVE TECHNOLOGY 2006年第12期24卷 4895-4902页

作者： Pechenkin, Vladimir Kschischang, Frank R. Univ Toronto Edward S Rogers Sr Dept Elect & Comp Engn Toronto ON M5S 3G4 Canada

This paper considers the application of constrained coding to 40-Gb/s dispersion-managed single-channel optical communication systems limited by intrachannel four-wave mixing (IFWM). It is shown that when transmitted sequences obey the so-called (2, infinity) constraint, runlength-limited codes can be designed to not only suppress ghost pulse formation but also improve the data rate by as much as 50% without increasing the transmission bandwidth. Since IFWM is a highly pattern-dependent effect, coding schemes with certain characteristics are preferable. Two different codes with simple encoding and decoding algorithms are constructed, and their performance is analyzed and compared to that of a realistic benchmark system. One of the codes turns out to be consistently better than the other due to its superior statistical properties. The qualitative conclusions are confirmed by numerical simulations. An extension of the method to multichannel links is also considered, and similar gain in data rate is demonstrated.

关键词： constrained coding fiber-optic communications ghost pulses intrachannel four-wave mixing (IFWM)

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