A5000976537- Advanced Wireless Communication Techniques
- Error Correcting Code Techniques
- Cellular Automata and Applications
- Coding theory and cryptography
- Magnetic properties of thin films
- Advanced Data Storage Technologies
- Algorithms and Data Compression
- Semiconductor Lasers and Optical Devices
- Wireless Communication Networks Research
- Advancements in PLL and VCO Technologies
- Characterization and Applications of Magnetic Nanoparticles
- DNA and Biological Computing
- Blind Source Separation Techniques
- Ferroelectric and Negative Capacitance Devices
- Adhesion, Friction, and Surface Interactions
- Power Line Communications and Noise
- Iterative Learning Control Systems
- Photonic and Optical Devices
- Spacecraft Design and Technology
- Advanced Adaptive Filtering Techniques
- Satellite Communication Systems
- Advanced Electrical Measurement Techniques
- Interconnection Networks and Systems
- Advanced Wireless Network Optimization
- graph theory and CDMA systems
IBM Research - Zurich
2003-2021
IBM (United States)
1997-2015
Linde (United States)
1987-1989
The realization of a digital recording system using partial-response class-IV signaling with maximum-likelihood sequence detection (MLSD) is described. To perform MLSD at the high data rates encountered in systems, simple implementation Viterbi detector based on difference-metric algorithm developed. Decision-directed schemes for gain control and timing recovery, tracking variations phase during readback, fast initial adjustment from known preamble are presented. dynamic behavior algorithms...
The recording performance of a new magnetic tape based on ultra-fine, perpendicularly-oriented BaFe particles was investigated. Specifically, using low lateral motion demonstration platform, servo pattern written the advanced perpendicularly oriented medium, friction head technology, novel synchronous channel design, and control concepts, we were able to demonstrate record closed-loop track-follow with 23.4 nm standard deviation position-error signal, roughly one order magnitude better than...
The recording performance of a prototype magnetic tape based on perpendicularly oriented barium ferrite particles is investigated using an enhanced field write head and 90 nm wide giant-magnetoresistive reader. A linear density 680 kbits/in with postdetection byte-error rate (BER) <;3.2e-2 demonstrated recorded data processed by software read channel noise-predictive maximum likelihood detection. With this detector error rate, user BER <;1e-20 can be achieved means product correction coding...
A prototype perpendicularly oriented sputtered tape sample was investigated using a high-moment write head and 48 nm-wide tunneling magnetoresistive hard disk drive read head. linear density of 818 kbpi with post-detection byte-error rate <;0.023 demonstrated based on measured recording data software channel that used an extended version the noise-predictive maximum-likelihood detection scheme tracks mean data-dependent noise. Using previously reported iterative decoding architecture, user...
The performance of magnetic recording systems that include conventional modulation codes combined with multiple parity bits is studied. Various measures, including bit error rate at the output time inverse precoder, byte probability input Reed-Solomon (RS) decoder and sector rate, are used to evaluate various coding/detection schemes. Suboptimum detection/decoding schemes consisting a 16-state noise-predictive maximum-likelihood (NPML) detector followed by parity-based post-processing,...
We investigated the performance of a barium ferrite tape medium in linear recording, using giant-magnetoresistive read head 0.5 mum track width. A density 400 kbpi with an error rate 6 times 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-5</sup> was demonstrated based on measured recording data and simulated channel advanced noise predictive maximum likelihood detection schemes. Using timing-based servo format that reduces position signal...
We examine the issue of scaling magnetic tape-recording to higher areal densities, focusing on challenges achieving 100 Gb/in <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> in linear tape format. The current highest achieved density demonstrations 6.7 and 23.0 helical scan format provide a reference for this assessment. argue that controlling head-tape interaction is key high density, whereas track-following reel-to-reel servomechanisms...
The recording performance of a new prototype magnetic tape based on perpendicularly oriented strontium ferrite particles is investigated using 29 nm wide tunneling magnetoresistive reader. At linear density 702 kbpi, post-detection byte-error rate (BER) 2.8e-2 demonstrated measured data and software read channel. channel uses 64-state implementation an extended version data-dependent noise-predictive maximum-likelihood detection scheme that tracks the first- second-order statistics noise....
Multi level sequences with a spectral null of order M at frequency f, meaning that the power density, and its first 2M-1 derivatives vanish are characterized by finite-state transition diagrams (FSTDs) whose edge labels satisfy bounds on variation Mth-order running digital sum (RDS). Necessary sufficient conditions for FSTDs higher constraints DC an arbitrary submultiple symbol derived. Analytical results given concerning performance codes satisfying RDS constraint partial-response channels....
The recording performance of a new magnetic tape based on perpendicularly oriented barium ferrite particles was investigated using 90-nm-wide giant-magnetoresistive reader and prototype enhanced-field write head. A linear density 600 kb/in with postdetection byte-error rate <;3 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup> demonstrated measured data software read channel that used noise-predictive maximum likelihood detection...
This article provides an overview of some the work that is ongoing in IEEE P802.3bj 100 Gb/s Backplane and Copper Cable Task Force. The task force standardizing Ethernet at over a 4-lane backplane channel as well across copper cable. We first describe background market drivers for this technology, then give various technologies are used to solve challenging problems running mediums data rate 25 Gb/s. Also discussed details forward error correction, transcoding physical layer coding employed...
Equalization and noise prediction followed by sequence detection postprocessing are studied for double-layer perpendicular recording channels that corrupted electronics transition noise. The performance of various outer coding schemes, such as conventional Reed-Solomon codes with 8and 10-bit symbols low-density parity check codes, is evaluated, a signal-processing perspective presented both longitudinal channels. Finally, the capacity characterized.
A robust error control scheme for data transmission in CDMA-based cellular systems is proposed which employs outer Reed-Solomon codes concatenated with inner convolutional codes. The performance of this analyzed assuming nonperiodic random spreading sequences and a Rake receiver perfect knowledge the channel. In particular, simple model memoryless coding channel that encompasses effects multiple access interference, self-noise thermal noise first derived. Using new tight upper bounds on bit-...
A new twins constraint for maximum transition run (MTR) codes is introduced to eliminate quasi-catastrophic error propagation in sequence detectors generalized partial response channels with spectral nulls both at dc and the Nyquist frequency. Two variants of that depend on whether detector trellis unconstrained or j-constrained are studied. Deterministic finite-state diagrams present specified, capacity class MTR constraints computed. The connection between (G,I) MTR(j) clarified. Code...
Timing-based servo (TBS) is a powerful technology widely used in state-of-the-art tape systems for track following. To optimize TBS future operating points with aggressive track-density scaling, an accurate model needed to characterize how the read head geometry, format parameters, and magnetic media properties affect readback signal. In this paper, we derive new analytical closed-form expressions signal of shielded magneto-resistive (MR) heads scanning over transitions patterns. The...
For 2-D product codes used in tape storage, the mapping of error-correction-coding (ECC) blocks (EBs) into physical (PBs) on magnetic is generalized. The 3-D that have same code rate and EB size as interleaved currently storage are proposed. codes, a new family mappings EBs PBs introduced, which fulfills stringent burst-error-correction requirements storage. capability words recorded analyzed function track rotation, linear density, ECC parameters. performance limits tape-storage channel...
We present a reverse concatenation (RC) architecture using Reed-Solomon (RS) error-correction codes (ECCs). The scheme employs very-high-rate pre-RS modulation followed by RS parity symbol insertion. in the RC scheme, which facilitate timing recovery and automatic gain control reduce detector path memory, are of same type as that have been used generalized partial-response maximum-likelihood (PRML) detection systems
The implementation of a 25.6-Gb/s four-level pulse-amplitude-modulation (4-PAM) reduced-state sliding-block Viterbi detector (VD) is presented. power consumption the VD 105mW at supply voltage 0.7 V, corresponding to an energy efficiency 4.1 pJ/b. A data rate 30.4 Gb/s achieved with 5.3 pJ/b 0.8 V. VD, implemented in experimental chip fabricated 14-nm CMOS FINFET, exploits set-partitioning principles and embedded per-survivor decision feedback reduce complexity consumption. active area 12...
The implementation of a digital four-level pulse-amplitude-modulation reduced-state sliding-block Viterbi detector (VD) with two substates and embedded per-survivor decision-feedback taps operating at one-eighth the modulation rate is described. Implemented in an experimental chip fabricated 14nm CMOS, VD designed to recover data 25.6 Gb/s over emulated time-dispersive channel. power consumption together test circuitry 105mW supply 0.7V, achieving overall energy efficiency 4.1 pJ/b. At 0.8V,...
New tight upper bounds on the performance or convolutional codes over Rayleigh and Rician fading channels are presented. These can be expressed in terms of generating function particularly for bit error rates lower than 10/sup -3/.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>
Two types of master-slave networks are investigated: oneway and two-way networks. The one-way System is a generalization the well-known hierarchical tree system. system novel concept. Sufficient stability conditions given for both network types. After synchronization achieved, frequency drift rate all oscillators in approaches master oscillator. steady-state differences between their variances computed six configurations practical interest. A performance comparison different connectivities...
We investigate the impact of synchronization and survivor path memory lengths on latency error rate a sliding-block receiver that implements Viterbi algorithm for high-speed data transmission over dispersive channels. All previous work detection has assumed length equals length. However, we demonstrate both these differ significantly from each other in an optimized parallelized detector design which minimizes implementation complexity while achieving error-rate performance with very long...
Timing-based servo signals, which are read back from dedicated patterns on tape to generate estimates for the operation of reel-to-reel and track-follow servomechanisms, characterized by a first-order position jitter noise pulse-width variation model. A method identification signal parameters evaluation relative contributions additive medium components is presented. The performance matched-filter detection binary symbols that embedded in recorded using pulse-position modulation investigated,...
An error control scheme for data transmission in code division multiple access (CDMA) cellular systems is proposed. The forward correction employs Reed-Solomon (RS) outer codes concatenated with convolutional inner codes. New tight upper bounds on the performance independent Rayleigh fading multipath channels are derived. Using these and invoking Gaussian assumption interference, of coding evaluated. Furthermore, design examples RS at 9.6 128 kbit/s CDMA presented. Finally, capacity a system...