An Analytical Approach for Performance Evaluation of Bit-Patterned Media Channels

Nabavi, S.; Jeon, Seungjune; Kumar, B. V. K. Vijaya

doi:10.1109/jsac.2010.100202

Cited by 13 publications

(4 citation statements)

References 19 publications

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“…Chapter 2 was published in [44], it was shown that the method can be successfully extended and applied to another type of channel, bit pattern media channels, by Nabavi in [72].…”

Section: Thesis Contributionsmentioning

confidence: 99%

“…The proposed method is a useful technique when we extend the Viterbi detectors to soft output Viterbi algorithm (SOVA) detectors, which can be used with LDPC codes, because the hard decision part of the output of the SOVA is the same as that of the conventional Viterbi detectors. After the proposed method in Chapter 2 was published in [44], it was shown that the method can be successfully extended and applied to another type of channel, bit pattern media channels, by Nabavi in [72].…”

Section: Thesis Contributionsmentioning

confidence: 99%

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Low-Density Parity Check Codes

Wu¹

2009

Contemporary Coding Techniques and Applications for Mobile Communications

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For high density magnetic recording channels and memory systems, low-density parity-check (LDPC) codes with probabilistic decoding are replacing Reed-Solomon (RS) codes or Bose-Chaudhuri-Hocquenghem (BCH) codes with conventional algebraic decoding. The main benefit of LDPC codes over the RS and BCH codes is that LDPC codes can provide lower error probabilities than equivalent conventional codes if the conditions of magnetic recording channels or memory systems are the same. In other words, in order to achieve the same error probabilities, LDPC codes can tolerate lower signal-to-noise-ratio conditions than the conventional codes, which can imply higher densities and lower media costs. These advantages of LDPC codes are possible at the cost of the increased decoder complexity over the conventional decoding.The main themes of this thesis are (1) to determine probabilistic input to the LDPC decoders from the channel detectors in magnetic recording channels or memory systems with low complexity and (2) AcknowledgmentsI would like to thank Prof. Kumar for providing me with a unique opportunity and an ideal environment to study signal processing and error correcting codes for data storage and memory systems. I respect his patience and believing in students. I was very lucky and I will miss the time I stayed here.I would like to thank Prof. Bain, Prof. Li, and Dr. Cheng for reading my thesis during their busiest time and providing many suggestions and very detailed feedback.I would also like to thank Dr. Cheng for bringing my interest into the fascinating problem of protecting memory systems on spacecraft and for his very detailed comments on the manuscripts of the papers on this topic.

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“…Chapter 2 was published in [44], it was shown that the method can be successfully extended and applied to another type of channel, bit pattern media channels, by Nabavi in [72].…”

Section: Thesis Contributionsmentioning

confidence: 99%

Section: Thesis Contributionsmentioning

confidence: 99%

Low-Density Parity Check Codes

Wu¹

2009

Contemporary Coding Techniques and Applications for Mobile Communications

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“…Motivated by the superiority of data-storage density, large attention has been turned to 2D-ISI channels. The symmetric information rate (SIR) and the error performance of such channels have been thoroughly analysed in [9][10][11][12]. Parallel with the information-theoretical advancements, several sub-optimal detecting algorithms have been developed so as to reduce the complexity of BCJR detector without sacrificing much performance, e.g.…”

Section: Introductionmentioning

confidence: 99%

Finite‐length extrinsic information transfer analysis and design of protograph low‐density parity‐check codes for ultra‐high‐density magnetic recording channels

Fang

Han

Guan³

et al. 2016

IET Communications

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The authors study the performance of protograph low-density parity-check (LDPC) codes over two-dimensional (2D) intersymbol interference (ISI) channels in this study. To begin with, the authors propose a modified version of finitelength (FL) extrinsic information transfer (EXIT) algorithm so as to facilitate the convergence analysis of protograph codes. Exploiting the FL-EXIT analyses, the authors observe that the protograph codes optimised for 1D ISI channels, e.g. the 1D-ISI protograph code, cannot maintain their advantages in the 2D-ISI scenarios. To address this problem, the authors develop a simple design scheme for constructing a family of rate-compatible improved protograph (RCIP) codes particularly for 2D-ISI channels, which not only outperform the 1D-ISI protograph code, but also are superior to the regular column-weight-3 code and optimised irregular LDPC codes in terms of the convergence speed and error performance. More importantly, such RCIP codes benefit from relatively lower error-floor as well as linear encoding and fast decoding. Thanks to these advantages, the proposed RCIP codes stand out as better alternatives in comparison with other error-correction codes for ultra-high-density data storage systems. IET CommunicationsResearch Article

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“…The modified VA takes into account the contribution of ITI and works on a complicated trellis with more branches entering and leaving each state. In [79] and [80] [66]. Unlike the equalizers described in [9] and [78] in which only the main track was equalized to a 1-D target, this equalizer equalized all three tracks to a 2-D target.…”

Section: Suboptimal Equalization and Detectionmentioning

confidence: 99%

Detection and decoding for two-dimensional interference channels

Yao¹

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In this thesis, we study the problem of communication over two-dimensional (2-D) interference channels which represent an important class of data storage and communication systems. The maximum-likelihood page detection (MLPD) for 2-D interference channels is firstly studied and the lower and upper performance bounds are derived. Although MLPD is computationally prohibitive and unachievable in practice, the performance bound of MLPD provides a benchmark of the optimal detection of 2-D interference channels. We also propose an approximated bounding method which can accurately predict the performance bound while greatly reducing the computational complexity. A joint iterative detection/decoding scheme (JIDDS) is proposed for 2-D interference system with low-density parity-check (LDPC) codes. The channel detector is composed of two constituent detectors that both adopt trellis-based maximum a posteriori probability (MAP) algorithms and they work in the down-track direction and cross-track direction, respectively. To achieve better performance, iterations are introduced between the two constituent detectors and among the constituent detectors with LDPC decoder. Simulation results show that the proposed scheme outperforms some existing algorithms. The better performance of JIDDS is achieved at the cost of higher computational complexity. A reduced-state channel detector is also proposed to save considerable complexity of the system but only degrade system performance marginally. In JIDDS, the channel detector and LDPC decoder work individually, which may result in some delays in detection/decoding. An appealing practical aspect of the decoding of LDPC codes is that it consists of many small, independent decoding functions (i.e., the variable nodes and check nodes) which can work in parallel. In order to make use of the low-delay advantage of LDPC codes, a joint message-passing decoding alvi gorithm (JMPDA) of LDPC codes and 2-D interference channels is proposed. The channel detector consists of many state-processing nodes which can be implemented in a completely parallel manner in conjunction with the decoding of LDPC codes. The performance of the JMPDA is almost the same as that of the JIDDS. An advantage of the JMPDA is its parallel implementation, leading to a high-speed decoder. Lastly, the extrinsic information transfer (EXIT) chart and density evolution (DE) are adopted in the analysis of the decoding of LDPC coded 2-D interference systems. The EXIT chart visualizes the evolution of mutual information between channel detection and LDPC decoding during the iterations. The effects of parameters to the decoding system are investigated by analyzing the EXIT curves. It is shown that given a good combination of parameters, the proposed algorithm will converge to the correct result. A graph representation of the JMPDA is explained. It is proved that the message-flow neighborhood of the JMPDA will be tree-like for a sufficiently long code length. It is further proved that the average performance of the JMPDA will concent...

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An Analytical Approach for Performance Evaluation of Bit-Patterned Media Channels

Cited by 13 publications

References 19 publications

Low-Density Parity Check Codes

Low-Density Parity Check Codes

Finite‐length extrinsic information transfer analysis and design of protograph low‐density parity‐check codes for ultra‐high‐density magnetic recording channels

Detection and decoding for two-dimensional interference channels

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