Coding and Iterative Detection for Magnetic Recording Channels: (531 The Springer International Series in Engineering and Computer Science)

This text should be a useful tool for researchers in both academia and industry who are interested in improving the performances of magnetic recording systems using new coding schemes. It proposes several new approaches for enhancing the performance of magnetic recording systems by coding and interpolated timing recovery. It provides a tutorial introduction to turbo codes, LDPC codes and their iterative detection schemes. The main emphasis, however, is placed on the simplification of the detector structures for the implementation of various codes. Chapter 1 introduces the model for magnetic recording channels and the challenges to the read channel detector designs. Chapter 2 discusses the turbo codes and the turbo equalization structure for ISI channels. Chapter 3 summarizes the major concepts of LDPC codes and their iterative detection algorithms based on belief propagation. Chapter 4 introduces the Decision Aid Equalization (DAE) structure to simplify iterative detection for ISI channels. Chapter 5 proposes an interpolated timing recovery scheme that facilitates symbol timing recovery by its `re-sampling' capability. The combination of the above-mentioned chapters leads to a new structure for implementing iterative detection on recording channels. Chapter 6 deviates from iterative detection to propose a simple code, the Interleaved Parity Check (IPC) code, and its reduced-complexity decoder, which is considered practical for implementation with currently available integrated circuit technology. Chapter 7 summarizes the book with a discussion on future research topics in this field. This text should be a useful reference for researchers and design engineers working on signal processing and coding for magnetic recording channels. It may also be used as a graduate text for courses on turbo codes.

Table of Contents:
1. Introduction to Magnetic Recording Channels.- 1. Magnetic Recoding Systems.- 2. Magnetic Recording Channel Model.- 3. Challenges in Read/Write Electronics Design.- 4. Read Channel Detectors.- 5. Outline of Book.- 2. Turbo Codes and Turbo Equalization.- 1. Introduction.- 2. Turbo Encoder and Coding Gain.- 3. Soft Iterative Decoding with BCJR Algorithm.- 4. Turbo Equalization for Magnetic Recording Channels.- 5. Summary.- APPENDIX 2.A Recursive Algorithms for ?’s and ?’s.- APPENDIX 2.B Approximation for the Log-Sum operation.- 3. Low-Density Parity-Check Codes.- 1. Introduction.- 2. Low-Density Parity-Check Codes.- 3. Iterative Detection and Belief Propagation.- 4. LDPC Codes for Magnetic Recording Channels.- 5. Summary and Discussion.- 4. Turbo Decision Aided Equalization.- 1. Decision Aided Equalization for Channel APP Detection.- 2. Implementation and Analysis of Turbo-DAE.- 3. Simulation Results.- 4. Turbo-DAE with Local BCJR.- 5. Summary and Conclusion.- APPENDIX 4.A APP Detection for Binary Markov Source with Finite Input Memory.- 1. Markov Source with Finite Input Memory.- 2. Modified BCJR Algorithm for Binary Markov Source with Finite Input Memory.- 5. Interleaved Parity Check Codes and Reduced Complexity Detection.- 1. Introduction.- 2. Error-events for the E2PR4 Channel.- 3. Interleaved Parity Check Codes.- 4. Reduced Complexity Detection for Interleaved Parity Check Codes.- 5. Performance of Interleaved Parity Check Codes.- 6. Summary and Conclusion.- 6. Interpolated Timing Recovery.- 1. Introduction.- 2. Conventional VCO-based Timing Recovery Loop.- 3. MMSE Interpolation Filter.- 4. FIR-ITR Loop Structure.- 5. Practical Issues.- 6. Simulation Results.- 7. Summary and Conclusion.- 7. Summary and Discussion.- 1. Speeding Turbo Decoding.- 2. TimingRecovery Schemes for Low SNR Channels.- 3. Turbo Decision Aided Equalization for Other Types of Channels.- References.