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A constrained-coding Alternative to MPPM

IEEE TRANSACTIONS ON COMMUNICATIONS 2012年第4期60卷 1013-1019页

作者： Liu, Siyu Kschischang, Frank R. Univ Toronto Dept Elect & Comp Engn Toronto ON M5S 3G4 Canada

Multipulse pulse position modulation (MPPM) has been widely proposed to improve data rate over traditional pulse position modulation (PPM) in free-space optical communication systems. Encoders for MPPM are typically lookup-table-based, thus restricting the practical size of MPPM codebooks. Power-of-two-sized MPPM codebooks typically do not have an efficient soft-in soft-out decoder, making them poorly suited for concatenation with an outer code under iterative decoding. In this paper, a new coding technique based on constrained coding is introduced that allows construction of codes which have an efficient encoding algorithm. More importantly, these new codes are suitable for iterative soft-decision decoding in concatenation with an outer error-correcting code. Simulation results for both the Gaussian and Poisson channels show that a serial concatenation with an outer low-density parity-check code (LDPC) can achieve between 2 to 3 dB coding gain over comparable Reed-Solomon and LDPC-coded MPPM systems.

关键词： Multipulse pulse-position modulation free-space optical communication constrained coding LDPC codes Poisson channel iterative decoding

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The Feedback Capacity of the Binary Erasure Channel With a No-Consecutive-Ones Input Constraint

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IEEE TRANSACTIONS ON INFORMATION THEORY 2016年第1期62卷 8-22页

作者： Sabag, Oron Permuter, Haim H. Kashyap, Navin Ben Gurion Univ Negev Dept Elect & Comp Engn IL-8410501 Beer Sheva Israel Indian Inst Sci Dept Elect Commun Engn Bangalore 560012 Karnataka India

The input-constrained erasure channel with feedback is considered, where the binary input sequence contains no consecutive ones, i.e., it satisfies the (1, infinity)-RLL constraint. We derive the capacity for this setting, which can be expressed as C-is an element of = max(0 <= p <= 0.5) (1-is an element of) H-b (p)/1+(1-is an element of) p, where is an element of is the erasure probability and Hb(.) is the binary entropy function. Moreover, we prove that a priori knowledge of the erasure at the encoder does not increase the feedback capacity. The feedback capacity was calculated using an equivalent dynamic programming (DP) formulation with an optimal average-reward that is equal to the capacity. Furthermore, we obtained an optimal encoding procedure from the solution of the DP, leading to a capacity-achieving, zero-error coding scheme for our setting. DP is, thus, shown to be a tool not only for solving optimization problems, such as capacity calculation, but also for constructing optimal coding schemes. The derived capacity expression also serves as the only non-trivial upper bound known on the capacity of the input-constrained erasure channel without feedback, a problem that is still open.

关键词： Feedback capacity constrained coding dynamic programming binary erasure channel runlength-limited (RLL) constraints

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The Capacity of String-Duplication Systems

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IEEE TRANSACTIONS ON INFORMATION THEORY 2016年第2期62卷 811-824页

作者： Farnoud (Hassanzadeh), Farzad Schwartz, Moshe Bruck, Jehoshua CALTECH Dept Elect Engn Pasadena CA 91125 USA Ben Gurion Univ Negev Dept Elect & Comp Engn IL-8410501 Beer Sheva Israel

It is known that the majority of the human genome consists of duplicated sequences. Furthermore, it is believed that a significant part of the rest of the genome also originated from duplicated sequences and has mutated to its current form. In this paper, we investigate the possibility of constructing an exponentially large number of sequences from a short initial sequence using simple duplication rules, including those resembling genomic-duplication processes. In other words, our goal is to find the capacity, or the expressive power, of these string-duplication systems. Our results include exact capacities, and bounds on the capacities, of four fundamental string-duplication systems. The study of these fundamental biologically inspired systems is an important step toward modeling and analyzing more complex biological processes.

关键词： Capacity DNA string duplication formal languages constrained coding

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Semiconstrained Systems

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IEEE TRANSACTIONS ON INFORMATION THEORY 2016年第4期62卷 1688-1702页

作者： Elishco, Ohad Meyerovitch, Tom Schwartz, Moshe Ben Gurion Univ Negev Dept Elect & Comp Engn POB 653 IL-84105 Beer Sheva Israel Ben Gurion Univ Negev Dept Math IL-84105 Beer Sheva Israel

When transmitting information over a noisy channel, two approaches, dating back to Shannon's work, are common: assuming the channel errors are independent of the transmitted content and devising an error-correcting code or assuming the errors are data dependent and devising a constrained-coding scheme that eliminates all offending data patterns. In this paper, we analyze a middle road, which we call a semiconstrained system. In such a system, which is an extension of the channel with the cost constraints model, we do not eliminate the error-causing sequences entirely, but rather restrict the frequency in which they appear. We address several key issues in this paper. The first is proving closed-form bounds on the capacity, which allow us to bound the asymptotics of the capacity. In particular, we bound the rate at which the capacity of the semiconstrained (0, k)-RLL tends to 1 as k grows. The second key issue is devising efficient encoding and decoding procedures that asymptotically achieve capacity with vanishing error. Finally, we consider delicate issues involving the continuity of the capacity and a relaxation of the definition of semiconstrained systems.

关键词： constrained coding capacity large deviations encoder construction

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Minimum Pearson Distance Detection Using Mass-Centered Codewords in the Presence of Unknown Varying Offset

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IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS 2016年第9期34卷 2510-2517页

作者： Immink, Kees Schouhamer Skachek, Vitaly Turing Machines Inc NL-3016 DK Rotterdam Netherlands Univ Tartu Inst Comp Sci EE-50409 Tartu Estonia

We consider the transmission and storage of data that use coded binary symbols over a channel, where a Pearson-distance-based detector is used for achieving resilience against additive noise, unknown channel gain, and varying offset. We study minimum Pearson distance (MPD) detection in conjunction with a set, S, of codewords satisfying a center-of-mass constraint. We investigate the properties of the codewords in S, compute the size of S, and derive its redundancy for asymptotically large values of the codeword length n. The redundancy of S is approximately (3/2) log(2) n + alpha, where alpha = log(2)(pi/24)(1/2) = -1.467.. for n odd and alpha = -0.467.. for n even. We describe a simple encoding algorithm whose redundancy equals 2 log(2) n+o(log n). We also compute the word error rate of the MPD detector when the channel is corrupted with additive Gaussian noise.

关键词： constrained coding storage systems flash memories minimum Pearson distance detection Euclidean distance baseline wander jamming channel mismatch

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Generalized Belief Propagation based Deliberate Bit Flipping Modulation coding 59

Generalized Belief Propagation based Deliberate Bit Flipping...

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59th Annual IEEE Global Communications Conference (IEEE GLOBECOM)

作者： Bahrami, Mohsen Vasic, Bane Univ Arizona Dept Elect & Comp Engn Tucson AZ 85721 USA

ISBN: (纸本)9781509013289

We propose a novel approach to modulation coding using the Generalized Belief Propagation (GBP) algorithm. The idea is to completely eliminate a constrained encoder and, instead, embed a constraint into an error correction codeword by deliberately flipping the bits that violate the constraint. The GBP algorithm is used to keep the number of flipped bits small in order not to overburden the decoder. We incorporate our method to impose the two-dimensional (2D) no isolated bit constraint on a low-density parity check (LDPC) coded 2D data array. Furthermore, we show that the number of flipped bits can be optimized so that it is not beyond the error correcting capability of the code. Applied to Two Dimensional Magnetic Recording (TDMR) systems, our approach results in an order of magnitude gain in the frame error rate.

关键词： Generalized Belief Propagation deliberate bit flipping constrained coding Two Dimensional Magnetic Recording low-density parity check codes

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Generalized Belief Propagation based Deliberate Bit Flipping Modulation coding

Generalized Belief Propagation based Deliberate Bit Flipping...

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IEEE Global Communications Conference

作者： Mohsen Bahrami Bane Vasic Department of Electrical and Computer Engineering University of Arizona

ISBN: (纸本)9781509013296

关键词： Generalized Belief Propagation Deliberate bit flipping constrained coding Two Dimensional Magnetic Recording Low-density parity check codes

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coding with Constraints: Minimum Distance Bounds and Systematic Constructions

Coding with Constraints: Minimum Distance Bounds and Systema...

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IEEE International Symposium on Information Theory (ISIT)

作者： Halbawi, Wael Thill, Matthew Hassibi, Babak CALTECH Dept Elect Engn Pasadena CA 91125 USA

ISBN: (纸本)9781467377041

We examine an error-correcting coding framework in which each coded symbol is constrained to be a function of a fixed subset of the message symbols. With an eye toward distributed storage applications, we seek to design systematic codes with good minimum distance that can be decoded efficiently. On this note, we provide theoretical bounds on the minimum distance of such a code based on the coded symbol constraints. We refine these bounds in the case where we demand a systematic linear code. Finally, we provide conditions under which each of these bounds can be achieved by choosing our code to be a subcode of a Reed-Solomon code, allowing for efficient decoding. This problem has been considered in multisource multicast network error correction. The problem setup is also reminiscent of locally repairable codes.

关键词： constrained coding distributed storage systematic code error-correcting code Reed-Solomon code

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Near-Field Passive RFID Communication: Channel Model and Code Design

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IEEE TRANSACTIONS ON COMMUNICATIONS 2014年第5期62卷 1716-1727页

作者： Barbero, Angela I. Rosnes, Eirik Yang, Guang Ytrehus, Oyvind Univ Valladolid Dept Matemat Aplicada E-47011 Valladolid Spain Univ Bergen Dept Informat Selmer Ctr N-5020 Bergen Norway Simula Res Lab Oslo Norway

This paper discusses a new channel model and code design for the reader-to-tag channel in near-field passive radio frequency identification (RFID) systems using inductive coupling as a power transfer mechanism. If the receiver resynchronizes its internal clock each time a bit is detected, the bit-shift channel used previously in the literature to model the reader-to-tag channel needs to be modified. In particular, we propose a discretized Gaussian shift channel as a new channel model in this scenario. We introduce the concept of quantifiable error avoidance, which is much simpler than error correction. The capacity is computed numerically, and we also design some new simple codes for error avoidance on this channel model based on insights gained from the capacity calculations. Finally, some simulation results are presented to compare the proposed codes to the Manchester code and two previously proposed codes for the bit-shift channel model.

关键词： Bit-shift channel channel capacity code design coding for error avoidance constrained coding discretized Gaussian shift channel inductive coupling radio frequency identification (RFID) reader-to-tag channel synchronization errors

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Code Rate of constrained Code for Phase Change Memories

Code Rate of Constrained Code for Phase Change Memories

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International Symposium on Information Theory and its Applications (ISITA)

作者： Takeyama, Shohei Kamabe, Hiroshi Gifu Univ Sch Informat Sci Gifu 5011193 Japan Gifu Univ Dept Informat Sci Gifu 5011193 Japan

ISBN: (纸本)9784885522925

Non-volatile memories, e.g., flash memories and phase change memories (PCM), have been widely used in computers and especially mobile computing devices because they have no mechanical components, they consume less power, and the access speeds of them are very high in comparison with hard disc drives. In magnetic recording systems, constrained codes are used so that stored data sequences are easily and correctly retrieved. In storage systems using non-volatile solid state memory, the constrained codes may also be employed but for different input constraints, e.g., (alpha, beta, p)-constraints introduced by A. Jiang et al. [4]. In this paper, two code construction methods for the (alpha, beta, p)-constraints for PCM are given. Next, a new constraint for PCM is introduced so that a constrained code with a higher code rate can be constructed from the constraint.

关键词： Non-volatile Memory Phase change memory constrained coding Two-dimensional constraint

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