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Author : Mohammed Dikko Almustapha
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (11 download)
Download or read book On Coding and Detection Techniques for Two-dimensional Magnetic Recording written by Mohammed Dikko Almustapha and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Morteza Mehrnoush
Publisher :
ISBN 13 :
Total Pages : 167 pages
Book Rating : 4.:/5 (969 download)
Download or read book Signal Processing and Coding for Two-dimensional Magnetic Recording written by Morteza Mehrnoush and published by . This book was released on 2016 with total page 167 pages. Available in PDF, EPUB and Kindle. Book excerpt: Initially, several turbo equalization systems for two-dimensional intersymbol interference (2D-ISI) channels are proposed. The systems' receivers consist of joint 2D-ISI equalizers with an irregular repeat accumulate (IRA) LDPC code.
Author : Zining Wu
Publisher : Springer Science & Business Media
ISBN 13 : 146154565X
Total Pages : 165 pages
Book Rating : 4.4/5 (615 download)
Download or read book Coding and Iterative Detection for Magnetic Recording Channels written by Zining Wu and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 165 pages. Available in PDF, EPUB and Kindle. Book excerpt: The advent of the internet age has produced enormous demand for in creased storage capacity and for the consequent increases in the amount of information that can be stored in a small space. While physical and media improvements have driven the majority of improvement in modern storage systems, signal processing and coding methods have increasing ly been used to augment those improvements. Run-length-limited codes and partial-response detection methods have come to be the norm in an industry that once rejected any sophistication in the read or write pro cessing circuits. VLSI advances now enable increasingly sophisticated signal processing methods for negligible cost and complexity, a trend sure to continue even as disk access speeds progress to billions of bits per second and terabits per square inch in the new millennium of the in formation age. This new book representing the Ph. D. dissertation work of Stanford's recent graduate Dr. Zining Wu is an up-to-date and fo cused review of the area that should be of value to those just starting in this area and as well those with considerable expertise. The use of saturation recording, i. e. the mandated restriction of two-level inputs, creates interesting twists on the use of communica tion/transmission methods in recording.
Author : Anantha Raman Krishnan
Publisher :
ISBN 13 :
Total Pages : 198 pages
Book Rating : 4.:/5 (78 download)
Download or read book Signal Processing for Two-Dimensional Magnetic Recording written by Anantha Raman Krishnan and published by . This book was released on 2011 with total page 198 pages. Available in PDF, EPUB and Kindle. Book excerpt: With magnetic storage devices already achieving storage densities of up to 400 Gigabits per square inch (Gb/in2), the state of the art is rapidly approaching theoretical limits (dictated by thermal stability concerns). Hence, there is an eort in the industry to develop alternative magnetic storage technologies. Two-dimensional magnetic recording (TDMR) is one such candidate technology. In contrast to other technologies(e.g. heat-assisted magnetic recording [1], bit-patterned media [2]) which rely on signicant changes being made to the recording medium, TDMR relies on the use of traditional recording media, while relying on signal processing to make improvements in the recording density. Though advantageous due to the fact that no drastic re-engineering of media is required, there are signicant challenges that need to be addressed in order to make TDMR a viable candidate for next-generation recordingsystems. The main challenges involved in TDMR arise due to (i) the small bit-area, along with an aggressive write/read process, which leads to a large amount of noise, and (ii) the two-dimensional nature of the recording process { so far not encountered in today's systems. Thus, a gamut of 2D signal processing algorithms need be developed for the compensation of errors occurring due to the aggressive write/read processes. In this dissertation, we present some of the work done with regard to the signal processing tasks involved in TDMR. In particular, we describe our work on (i) channel modelling, (ii) detection strategies, and (iii) error-correction coding strategies targetted at TDMR.
Author : Bane Vasic
Publisher : CRC Press
ISBN 13 : 0203490312
Total Pages : 742 pages
Book Rating : 4.2/5 (34 download)
Download or read book Coding and Signal Processing for Magnetic Recording Systems written by Bane Vasic and published by CRC Press. This book was released on 2004-11-09 with total page 742 pages. Available in PDF, EPUB and Kindle. Book excerpt: Implementing new architectures and designs for the magnetic recording read channel have been pushed to the limits of modern integrated circuit manufacturing technology. This book reviews advanced coding and signal processing techniques and architectures for magnetic recording systems. Beginning with the basic principles, it examines read/write operations, data organization, head positioning, sensing, timing recovery, data detection, and error correction. It also provides an in-depth treatment of all recording channel subsystems inside a read channel and hard disk drive controller. The final section reviews new trends in coding, particularly emerging codes for recording channels.
Author : İsmail Demirkan
Publisher :
ISBN 13 :
Total Pages : 165 pages
Book Rating : 4.:/5 (713 download)
Download or read book Coding and Detection for 2-dimensional Channels written by İsmail Demirkan and published by . This book was released on 2006 with total page 165 pages. Available in PDF, EPUB and Kindle. Book excerpt: Coding and detection techniques for one-dimensional (1-D) intersymbol interference (ISI) channels, particularly magnetic and optical recording channels, have been studied extensively for almost three decades. On the modulation coding side, the state-splitting algorithm has been developed to design efficient systematic modulation codes. On the detection side, Viterbi detector and decision-feedback equalization (DFE) have been well-understood. Two-dimensional (2-D) holographic data storage, has been developed to store the information page-wise instead of on 1-D tracks. This will signifficantly increase the storage density and read/write access of the information. However, most of the modulation coding and detection techniques for 1-D recording systems are unusable for 2-D holographic data storage. In this work, we present various methods for modelling and equalizing 2-D ISI channels. Some low complexity detectors, such as a threshold detector, have been proposed for certain 2-D ISI channels. One of the main problems of the holographic data storage is the misalignment between written and sampled data pages. This problem is addressed by using more detector pixels than data points, which is called oversampling. We also attempted to characterize the distance properties of certain 2-D ISI channels. An algorithm for finding error events is developed for any 2-D ISI channel. Unlike the 1-D constrained systems, the capacity of most 2-D constrained systems is not analytically known due to the lack of graph-based descriptions of such channels. This also complicates the design of efficient modulation codes. We propose algorithms for finding single-state and finite-state block codes for the hard-square constraint. The encoding and decoding of the modulation codes can be performed easily using codeword generating templates. We also propose an algorithm for finding single-state block codes for any 2-D constrained system represented by a set of forbidden patterns. For 1-D recording, we designed block codes satisfying the running digital sum (RDS) and time-varying maximum transition run (TMTR) constraints for perpendicular recording channels. The graphs of these constraints are combined to understand the design trade-off between the achievable coding rate and constraint parameters. The spectra of the combined constraints shows the properties of the constituent constraints. The modulations codes are designed by searching for all codewords satisfying certain constraint properties.
Author : Enfeng Jiang
Publisher :
ISBN 13 :
Total Pages : 136 pages
Book Rating : 4.:/5 (876 download)
Download or read book Channel Detection on Two-dimensional Magnetic Recording written by Enfeng Jiang and published by . This book was released on 2013 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author :
Publisher :
ISBN 13 :
Total Pages : 344 pages
Book Rating : 4.:/5 (659 download)
Download or read book Detection and Decoding for Magnetic Storage Systems written by and published by . This book was released on 2009 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt: The hard-disk storage industry is at a critical time as the current technologies are incapable of achieving densities beyond 500 Gb/in2, which will be reached in a few years. Many radically new storage architectures have been proposed, which along with advanced signal processing algorithms are expected to achieve much higher densities. In this dissertation, various signal processing algorithms are developed to improve the performance of current and next-generation magnetic storage systems. Low-density parity-check (LDPC) error correction codes are known to provide excellent performance in magnetic storage systems and are likely to replace or supplement currently used algebraic codes. Two methods are described to improve their performance in such systems. In the first method, the detector is modified to incorporate auxiliary LDPC parity checks. Using graph theoretical algorithms, a method to incorporate maximum number of such checks for a given complexity is provided. In the second method, a joint detection and decoding algorithm is developed that, unlike all other schemes, operates on the non-binary channel output symbols rather than input bits. Though sub-optimal, it is shown to provide the best known decoding performance for channels with memory more than 1, which are practically the most important. This dissertation also proposes a ternary magnetic recording system from a signal processing perspective. The advantage of this novel scheme is that it is capable of making magnetic transitions with two different but predetermined gradients. By developing optimal signal processing components like receivers, equalizers and detectors for this channel, the equivalence of this system to a two-track/two-head system is determined and its performance is analyzed. Consequently, it is shown that it is preferable to store information using this system, than to store using a binary system with inter-track interference. Finally, this dissertation provides a number of insights into the unique characteristics of heat-assisted magnetic recording (HAMR) and two-dimensional magnetic recording (TDMR) channels. For HAMR channels, the effects of laser spot on transition characteristics and non-linear transition shift are investigated. For TDMR channels, a suitable channel model is developed to investigate the two-dimensional nature of the noise.
Author : Lu Pan
Publisher :
ISBN 13 :
Total Pages : 216 pages
Book Rating : 4.:/5 (852 download)
Download or read book Coding and Signal Processing Techniques for High Efficiency Data Storage and Transmission Systems written by Lu Pan and published by . This book was released on 2013 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt: Generally speaking, a communication channel refers to a medium through which an information-bearing signal is corrupted by noise and distortion. A communication channel may result from data storage over time or data transmission through space. A primary task for communication engineers is to mathematically characterize the channel to facilitate the design of appropriate detection and coding systems. In this dissertation, two different channel modeling challenges for ultra-high density magnetic storage are investigated: two-dimensional magnetic recording (TDMR) and bit-patterned magnetic recording (BPMR). In the case of TDMR, we characterize the error mechanisms during the write/read process of data on a TDMR medium by a finite-state machine, and then design a state-based detector that provides soft decisions for use by an outer decoder. In the case of BPMR, we employ an insertion/deletion (I/D) model. We propose a LDPC-CRC product coding scheme that enables the error detection without the involvement of Marker codes specifically designed for an I/D channel. We also propose a generalized Gilbert-Elliott (GE) channel to approximate the I/D channel in the sense of an equivalent I/D event rate. A lower bound of the channel capacity for the BPMR channel is derived, which supports our claim that commonly used error-correction codes are effective on the I/D channel under the assumption that I/D events are limited to a finite length. Another channel model we investigated is perpendicular magnetic recording model. Advanced signal processing for the pattern-dependent-noise-predictive channel detectors is our focus. Specifically, we propose an adaptive scheme for a hardware design that reduces the complexity of the detector and the truncation/saturation error caused by a fix-point representation of values in the detector. Lastly, we designed a sequence detector for compressively sampled Bluetooth signals, thus allowing data recovery via sub-Nyquist sampling. This detector skips the conventional step of reconstructing the original signal from compressive samples prior to detection. We also propose an adaptive design of the sampling matrix, which almost achieves Nyquist sampling performance with a relatively high compression ratio. Additionally, this adaptive scheme can automatically choose an appropriate compression ratio as a function of.
Author :
Publisher :
ISBN 13 :
Total Pages : 564 pages
Book Rating : 4.:/5 (31 download)
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 564 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Bing Fan
Publisher :
ISBN 13 :
Total Pages : 146 pages
Book Rating : 4.:/5 (992 download)
Download or read book Multihead Multitrack Detection for Next Generation Magnetic Recording Systems written by Bing Fan and published by . This book was released on 2017 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt: Two dimensional magnetic recording (TDMR) is one of the leading technologies proposed to achieve ultra high storage density in the next generation hard disk drives. A typical read channel of TDMR can be approximated by a multihead multitrack (MHMT) model which is characterized by the intersymbol interference (ISI) in the downtrack direction and intertrack interference (ITI) in the crosstrack direction. In this dissertation, we aim to address two challenging problems that can potentially make the maximum likelihood (ML) detection for the MHMT channel impractical. One problem associated with the conventional ML detector is the ITI dependency of the ML trellis, which makes it inefficient to adapt to a time-varying ITI environment. We propose a novel detection method, called the weighted sum-subtract joint detection (WSSJD), to solve this issue. We show that the ITI interfering channels in MHMT system can be transformed to several parallel subchannels, whose joint trellis is independent of ITI. For the case when the receiver lacks the knowledge of ITI, we propose a gain loop structure which can be incorporated into WSSJD to efficiently track the ITI estimates. We present the implementation of WSSJD and simulation results for several widely-studied MHMT models including the 2H2T channel, the 3H3T channel, and the 3H2T channel. Another challenging problem is the exponentially increased computational complexity of the ML detector due to its multitrack processing scheme. We propose to use the reduced-state sequence estimation (RSSE) to mitigate this issue. The underlying idea is to drop less likely paths at early state during the detection by using a heavily reduced subset trellis. To apply RSSE to the MHMT channel, we find that the channel transformation developed in WSSJD offers a natural set partition principle on the input constellation that is necessary to successfully implement RSSE. The theoretical error event analysis shows a good consistency with the simulation results. Flash memory has faster access speed, lower power consumption, and better data integrity, which make it more attractive than the magnetic recording in many applications. However, the lifetime of flash memory is limited by the program/erase cycles. Write-once memory (WOM) codes are proposed to extend the flash memory lifetime by constraining the unidirectional changes of cell levels. In this work, we study the expected performance of WOM codes. Dynamic programming based algorithm is proposed to construct the optimal WOM updating function of a given labeling function.
Author : Erozan M. Kurtas
Publisher : CRC Press
ISBN 13 : 1420036491
Total Pages : 288 pages
Book Rating : 4.4/5 (2 download)
Download or read book Advanced Error Control Techniques for Data Storage Systems written by Erozan M. Kurtas and published by CRC Press. This book was released on 2018-10-03 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt: With the massive amount of data produced and stored each year, reliable storage and retrieval of information is more crucial than ever. Robust coding and decoding techniques are critical for correcting errors and maintaining data integrity. Comprising chapters thoughtfully selected from the highly popular Coding and Signal Processing for Magnetic Recording Systems, Advanced Error Control Techniques for Data Storage Systems is a finely focused reference to the state-of-the-art error control and modulation techniques used in storage devices. The book begins with an introduction to error control codes, explaining the theory and basic concepts underlying the codes. Building on these concepts, the discussion turns to modulation codes, paying special attention to run-length limited sequences, followed by maximum transition run (MTR) and spectrum shaping codes. It examines the relationship between constrained codes and error control and correction systems from both code-design and architectural perspectives as well as techniques based on convolution codes. With a focus on increasing data density, the book also explores multi-track systems, soft decision decoding, and iteratively decodable codes such as Low-Density Parity-Check (LDPC) Codes, Turbo codes, and Turbo Product Codes. Advanced Error Control Techniques for Data Storage Systems offers a comprehensive collection of theory and techniques that is ideal for specialists working in the field of data storage systems.
Author : Gee-Swee Poo
Publisher : Institute of Electrical & Electronics Engineers(IEEE)
ISBN 13 :
Total Pages : 790 pages
Book Rating : 4.3/5 (91 download)
Download or read book Proceedings of IEEE Singapore International Conference on Networks/International Conference on Information Engineering written by Gee-Swee Poo and published by Institute of Electrical & Electronics Engineers(IEEE). This book was released on 1995 with total page 790 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Bruce Edward B. Moision
Publisher :
ISBN 13 :
Total Pages : 252 pages
Book Rating : 4.:/5 (318 download)
Download or read book Constrained Coding and Detection for Magnetic Recording Channels written by Bruce Edward B. Moision and published by . This book was released on 2000 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Zheng Wu
Publisher :
ISBN 13 :
Total Pages : 122 pages
Book Rating : 4.:/5 (312 download)
Download or read book Channel Modeling, Signal Processing and Coding for Perpendicular Magnetic Recording written by Zheng Wu and published by . This book was released on 2009 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt: With the increasing areal density in magnetic recording systems, perpendicular recording has replaced longitudinal recording to overcome the superparamagnetic limit. Studies on perpendicular recording channels including aspects of channel modeling, signal processing and coding techniques are presented in this dissertation. To optimize a high density perpendicular magnetic recording system, one needs to know the tradeoffs between various components of the system including the read/write transducers, the magnetic medium, and the read channel. We extend the work by Chaichanavong on the parameter optimization for systems via design curves. Different signal processing and coding techniques are studied. Information-theoretic tools are utilized to determine the acceptable region for the channel parameters when optimal detection and linear coding techniques are used. Our results show that a considerable gain can be achieved by the optimal detection and coding techniques. The read-write process in perpendicular magnetic recording channels includes a number of nonlinear effects. Nonlinear transition shift (NLTS) is one of them. The signal distortion induced by NLTS can be reduced by write precompensation during data recording. We numerically evaluate the effect of NLTS on the read-back signal and examine the effectiveness of several write precompensation schemes in combating NLTS in a channel characterized by both transition jitter noise and additive white Gaussian electronics noise. We also present an analytical method to estimate the bit-error-rate and use it to help determine the optimal write precompensation values in multi-level precompensation schemes. We propose a mean-adjusted pattern-dependent noise predictive (PDNP) detection algorithm for use on the channel with NLTS. We show that this detector can offer significant improvements in bit-error-rate (BER) compared to conventional Viterbi and PDNP detectors. Moreover, the system performance can be further improved by combining the new detector with a simple write precompensation scheme. Soft-decision decoding for algebraic codes can improve performance for magnetic recording systems. In this dissertation, we propose two soft-decision decoding methods for tensor-product parity codes. We also present a list decoding algorithm for generalized error locating codes.
Author : K.H.J. Buschow
Publisher : Elsevier
ISBN 13 : 0080457657
Total Pages : 1361 pages
Book Rating : 4.0/5 (84 download)
Download or read book Concise Encyclopedia of Magnetic and Superconducting Materials written by K.H.J. Buschow and published by Elsevier. This book was released on 2005-12-28 with total page 1361 pages. Available in PDF, EPUB and Kindle. Book excerpt: Magnetic and superconducting materials pervade every avenue of the technological world – from microelectronics and mass-data storage to medicine and heavy engineering. Both areas have experienced a recent revitalisation of interest due to the discovery of new materials, and the re-evaluation of a wide range of basic mechanisms and phenomena.This Concise Encyclopedia draws its material from the award-winning Encyclopedia of Materials and Engineering, and includes updates and revisions not available in the original set -- making it the ideal reference companion for materials scientists and engineers with an interest in magnetic and superconducting materials. - Contains in excess of 130 articles, taken from the award-winning Encyclopedia of Materials: Science and Technology, including ScienceDirect updates not available in the original set - Each article discusses one aspect of magnetic and superconducting materials and includes photographs, line drawings and tables to aid the understanding of the topic at hand - Cross-referencing guides readers to articles covering subjects of related interest
Author : Sharon Aviran
Publisher :
ISBN 13 :
Total Pages : 136 pages
Book Rating : 4.:/5 (734 download)
Download or read book Constrained Coding and Signal Processing for Data Storage Systems written by Sharon Aviran and published by . This book was released on 2006 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt: Constrained codes for digital storage systems are studied. A method for improving signal detection in digital magnetic recording systems is also investigated. The bit stuffing algorithm is a technique for coding constrained sequences by the insertion of bits into an arbitrary data sequence. This approach was previously introduced and applied to the family of $(d, k)$ constraints. Results show that the maximum average rate of the bit stuffing code achieves the Shannon capacity when $k=d+1$ or $k=\infty$, and fails to achieve capacity for all other $(d, k)$ pairs. A modification to the bit stuffing algorithm is proposed that is based on the addition of controlled bit flipping. It is shown that the modified scheme achieves improved average rates over bit stuffing for most $(d, k)$ constraints. All $(d, k)$ constraints for which this scheme produces codes with an average rate equal to the Shannon capacity are determined. A general framework for the construction of $(d, k)$-constrained codes from variable-length source codes is presented. Optimal variable-length codes under the general framework are investigated. The construction of constrained codes from variable-length source codes for encoding unconstrained sequences of independent but biased (as opposed to equiprobable) bits is also considered. It is shown that one can use the Tunstall source coding algorithm to generate optimal codes for a partial class of $(d, k)$ constraints. Bit-stuffing schemes which encode arbitrary inputs into two-dimensional (2-D) constrained arrays are presented. The class of 2-D $(d, \infty)$ constraints as well as the `no isolated bits' constraint are considered. The proposed schemes are based on interleaving biased bits with multiple biases into a 2-D array, while stuffing extra bits when necessary. The performance of the suggested schemes is studied through simulations. A method for joint detection and decoding of coded transmission over magnetic recording channels is considered. The standard framework of turbo equalization is modified to account for the colored noise present in high-density magnetic recording systems. The modified scheme incorporates a noise prediction algorithm, which iteratively and selectively whitens the noise, while utilizing the information produced by the turbo equalization scheme. Simulation results demonstrate the performance improvements obtained by the proposed scheme.
