Nopparit Intharasombat

Least square equalization and variable thresholding for 3D page-oriented optical data storage systems

We describe equalization and detection techniques that overcome both inter-page interference (IPI) and intersymbol interference (ISI) in volumetric (3D) page-oriented optical data storage (PODS) systems.

Iterative detection for interpage interference in imaging page-oriented optical data storage

Page-oriented optical data storage (PODS) has advantages in data transfer rate and storage capacity over planar type data storage. The increase in capacity comes from the use of the third spatial dimension and increased packing density from reduced pixel pitch and inter-page spacing. We present a low complexity iterative detection procedure that combats inter-page interference (IPI) and intersymbol interference (ISI) while maintaining acceptable bit error rate performance.

Iterative detection for imaging page-oriented optical data storage

We present iterative modulation decoding and detection techniques that overcome effects of intersymbol interference in imaging page-oriented optical data storage to improve the usable density and capacity while maintaining acceptable bit-error rates.

Variable threshold detection for 3D page-oriented optical data storage systems

We propose a new method to determine dynamically the threshold in volumetric (3D) page-oriented optical data storage (PODS) systems that use an incoherent (non-holographic) imaging format. In these systems, the inter-symbol interference (ISI) and inter-page interference (IPI) that occurs with very high data packing density are two major sources of error during data retrieval. Traditional readout systems based on a fixed binary decision threshold provide poor results. Our variable threshold detection method identifies the amount of interference from three dimensions for each data element (pixel) and adjusts the threshold value based on that information. In simulation results, the variable threshold method exhibits significant improvement over traditional detection methods.

Iterative detection for imaging page-oriented optical data storage systems

Imaging page-oriented optical data storage, with its high bit packing density and many parallel readout channels, offers a solution for high capacity data storage with fast data transfer rate. As in any data storage system, increasing the packing density increases the effect of inter-symbol interference (ISI) and inter-page interference (IPI). We describe a combination of modulation encoding/decoding and error correction that overcomes this interference allowing high packing density in the presence of noise while maintaining acceptable bit error rate (BER). We also describe an extension of the algorithm to multi-level (grayscale) encoding.

Variable Threshold and Fixed-Point Arithmetic Least Square Equalization in Page-Oriented Optical Data Storage

We describe significant improvements from novel variable threshold and fixed-point arithmetic least square equalization modulation detection for volumetric (3D) page-oriented optical data storage (PODS) systems with extreme intersymbol interference (ISI) and interpage interference (IPI).

Multi-Level Encoding and Detection for Imaging Page-Oriented Optical Data Storage

Imaging page-oriented optical data storage can record data bits in grayscale, with potential total capacity benefits. We describe an extension of our binary iterative decision feedback modulation detection technique to multi-level operation.

Least square equalization for multi-level 3D page-oriented optical data storage systems

We describe non-adaptive and adaptive least square equalization and detection techniques for two-level and multi-level volumetric (3D) page-oriented optical data storage (PODS) systems. The procedures overcome the effects of noise and both inter-page interference (IPI) and intersymbol interference (ISI) to reduce system bit-error-rate (BER).

Iterative decision feedback processing for 3D imaging page-oriented optical data storage

We describe iterative decision feedback 3D signal processing techniques that overcome inter-page interference (IPI) and inter-symbol interference (ISI) in imaging page-oriented optical data storage systems. We compare their performance with alternative equalization and maximum-likelihood detection, describe resulting capacity improvements, and extensions to multi-level systems.

Modulation encoding and iterative detection for imaging page-oriented optical data storage

Various types of holographic and imaging volumetric page-oriented optical data storage (PODS) systems have great potential to provide data storage with larger capacity, faster access time, and higher transfer rates [1]. The usable data capacity is quantified by the code rate, or percentage of theoretical storage capacity that is actually useable for storing information at a minimum acceptable bit-error rate (BER). The BER is controlled by using a combination of channel coding (error-correcting coding or ECC) on the digital data, and a modulation coding procedure that formats the data for the physical storage medium. For a given coding scheme and level of signal processing, increasing the data packing density increases the code rate at the expense of lower BER due to the presence of spatial intersymbol interference (ISI), interpage interference (IPI) and noise. ISI and IPI are due to the point-spread function of the recording and readout optics. Some modulation codes [2] add redundant information to preserve the signal integrity and simplify the detection procedure. We describe a n iterative computational imaging technique that maintains a minimum required modulation coding BER (generally 10-3 or better) while improving the overall code rate and capacity of a page-oriented imaging optical data storage system