Patent application number | Description | Published |
20100042897 | SELECTIVELY STRENGTHENING AND WEAKENING CHECK-NODE MESSAGES IN ERROR-CORRECTION DECODERS - In one embodiment, an LDPC decoder has a plurality of check-node units (CNUs) and a controller. Initially, the CNUs generate check-node messages based on an initial offset value selected by the controller. If the decoder converges on a trapping set, then the controller selects new offset values for missatisfied check nodes (MSCs), the locations of which are approximated, and/or unsatisfied check nodes (USCs). In particular, offset values are selected such that (i) the messages corresponding to the MSCs are decreased relative to the messages that would be generated using the initial offset value and/or (ii) the messages corresponding to the USCs are increased relative to the messages that would be generated using the initial offset value. Decoding is then continued for a specified number of iterations to break the trapping set. In other embodiments, the controller selects scaling factors rather than, or in addition to, offset values. | 02-18-2010 |
20110029826 | Systems and Methods for Re-using Decoding Parity in a Detector Circuit - Various embodiments of the present invention provide systems and methods for data processing. For example, a method for data processing is disclosed that includes receiving an LDPC codeword, and grouping active bits from the LDPC codeword into a series of data bits including one or more user data bits including and at least one LDPC parity bit. The series of data bits satisfies an LDPC parity equation. | 02-03-2011 |
20110029835 | Systems and Methods for Quasi-Cyclic LDPC Code Production and Decoding - Various embodiments of the present invention provide systems and methods for generating a parity check matrix used in data processing. As an example, a method for generating a parity check matrix including selecting a non-affiliated variable node; identifying a check node of the lowest degree; connecting a first edge of the non-affiliated variable node to the identified check node; and connecting one or more additional edges of the non-affiliated variable node to check nodes in accordance with a quasi-cyclic constraint associated with a circulant is disclosed. | 02-03-2011 |
20110029839 | Systems and Methods for Utilizing Circulant Parity in a Data Processing System - Various embodiments of the present invention provide systems and methods for data processing. For example, a method for data processing is disclosed that includes receiving a codeword that has at least a first circulant with a plurality of data bits and a first circulant parity bit, a second circulant with a plurality of data bits and a second circulant parity bit, and one or more codeword parity bits. The methods further include decoding the codeword using the one or more codeword parity bits to access the first circulant and the second circulant, performing a first circulant parity check on the first circulant, and performing a second circulant parity check on the second circulant. | 02-03-2011 |
20110119553 | SUBWORDS CODING USING DIFFERENT ENCODING/DECODING MATRICES - In a communications system that demultiplexes user data words into multiple sub-words for encoding and decoding within different subword-processing paths, the minimum distance between bit errors in an extrinsic codeword can be increased by having corresponding subword encoders/decoders in the different subword-processing paths perform subword encoding/decoding with different encoder/decoder matrices. | 05-19-2011 |
20110199699 | FREQUENCY-BASED APPROACH FOR DETECTION AND CLASSIFICATION OF HARD-DISC DEFECT REGIONS - In a hard-disc drive read channel, frequency-based measures are generated at two different data frequencies (e.g., 2T and DC) by applying a transform, such as a discrete Fourier transform (DFT), to signal values, such as ADC or equalizer output values, corresponding to, e.g., a 2T data pattern stored on the hard disc. The frequency-based measures are used to detect defect regions on the hard disc and/or to classify defect regions as being due to either thermal asperity (TA) or drop-out media defect (MD). | 08-18-2011 |
20110235490 | AMPLITUDE-BASED APPROACH FOR DETECTION AND CLASSIFICATION OF HARD-DISC DEFECT REGIONS - In a hard-disc drive, a defect region on the hard disc is classified as corresponding to either thermal asperity (TA) or media defect (MD) by generating two statistical measures. A first measure (e.g., ∝ | 09-29-2011 |
20110311002 | Turbo-Equalization Methods For Iterative Decoders - Certain embodiments of the present invention are improved turbo-equalization methods for decoding encoded codewords. In one embodiment, in global decoding iteration i, the magnitude values of all decoder-input LLR values (L | 12-22-2011 |
20120079340 | COMMUNICATIONS SYSTEM EMPLOYING LOCAL AND GLOBAL INTERLEAVING/DE-INTERLEAVING - In one embodiment, a communications system has a write path and a read path. In the write path, a local/global interleaver interleaves a user data stream, and an error-correction (EC) encoder encodes the user data stream to generate an EC codeword. A local/global de-interleaver de-interleaves the parity bits of the EC codeword, and both the original un-interleaved user data and the de-interleaved parity bits are transmitted via a noisy channel. In the read path, a channel detector recovers channel soft-output values corresponding to the codeword. A local/global interleaver interleaves the channel values, and an EC decoder decodes the interleaved values to recover the original codeword generated in the write path. A de-multiplexer de-multiplexes the user data from the parity bits. Then, a local/global de-interleaver de-interleaves the user data to obtain the original sequence of user data that was originally received at the write path. | 03-29-2012 |