Integrated Device Technology, Inc.

Pmc-sierra Us, Inc.

Microsemi Storage Solutions (u.s.), Inc.

Microsemi Solutions (us), Inc.

Rise Technology Company

Zettacom, Inc.

Christopher I W Norrie

Rino Micheloni

Alessia Marelli

Peter Onufryk

Matthew D Ornes

Gene K Chui

Robert James Divivier

Ihab Jaser

Onchuen (Daryn) Lau

Chris D Bergen

King-Shing (Frank) Chui

Luca Crippa

Christopher Bergen

Thomas J Norrie

Kenneth K Munson

Lambert Fong

Sean P Cummins

Methods and apparatus are disclosed for decoding low-density parity check (LDPC) encoded data using a parity check matrix having a plurality of layers. The apparatus includes a decoder having circuitry to decode, layer by layer, a LDPC codeword utilizing functional adjustments and an algorithmic approximation to belief propagation to provide an estimate of the LDPC codeword, the functional adjustments including layer specific parameters for at least two layers of the parity check matrix associated with the LDPC codeword.

Method and apparatus for layer-specific LDPC decoding

A method to decode low-density parity check (LDPC) encoded data using a parity check matrix having a plurality of layers, includes receiving a plurality of values at a decoder. Each value of the plurality of values represents one of a plurality of bits of an LDPC codeword encoded using the parity check matrix. The LDPC codeword is decoded using layered scheduling. A functional adjustment is applied to an approximation of belief propagation used during the decoding. At least one layer specific functional adjustment is used to provide an estimate of the codeword. An apparatus to decode low-density parity check (LDPC) encoded data using a parity check matrix having a plurality of layers includes a decoder. The decoder includes circuitry to decode, layer by layer, the LDPC encoded data utilizing functional adjustments and an algorithmic approximation to belief propagation to provide an estimate of the LDPC codeword. The functional adjustments include layer specific parameters for at least two layers of the parity check matrix associated with the codeword.

Layer specific LDPC decoder

A nonvolatile memory storage controller is provided for delivering log likelihood ratios (LLRs) to a low-density parity check (LDPC) decoder for use in the decoding of an LDPC encoded codeword. The controller includes read circuitry for reading an LDPC encoded codeword stored in a nonvolatile memory storage module using a plurality of soft-decision reference voltages to provide a plurality of soft-decision bits representative of the codeword. The controller further includes a plurality of neighboring cell contribution LLR look-up tables representative of the contribution of the neighboring cells to threshold voltage distribution of the memory storage module. The controller provides the LLRs from the appropriate LLR look-up table to an LDPC decoder for the subsequent decoding of the codeword.

System and method for higher quality log likelihood ratios in LDPC decoding

A system and method reading, accumulating and processing soft information for use in LDPC decoding. In accordance with the present invention, an LDPC decoder includes accumulation circuitry to receive soft reads of a cell of the nonvolatile memory storage module and to produce an accumulated soft read that can be used to identify an appropriate LLR for the cell. The accumulation circuitry of the present invention may include, an accumulation RAM, an arithmetic logic unit (ALU) and a soft accumulation control and sequencing module for accumulating and processing soft information for use in LDPC decoding.

System and method for accumulating soft information in LDPC decoding

A nonvolatile memory controller includes memory storage configured to store a two-index look-up table that includes a Log-Likelihood Ratio (LLR), hard-and-soft-decision bits associate with the LLR and a neighboring cell read pattern associated with the LLR. Read circuitry is configured to perform a plurality of reads of a cell of a nonvolatile memory storage module at different read voltage levels to generate target cell hard-and-soft-decision bits and configured to read neighboring cells to generate neighboring cell reads. Neighboring cell processing circuitry combines the neighboring cell reads to generate a neighboring cell read pattern. Look-up circuitry accesses the two-index look-up table using the target cell hard-and-soft-decision bits and the neighboring cell read pattern to identify the corresponding LLR for use in Low-Density Parity Check (LDPC) decoding of a codeword stored in the nonvolatile memory storage module.

High quality log likelihood ratios determined using two-index look-up table

An integrated circuit device for correcting errors in data read from memory cells includes a decoder, an encoder and a data management module. The data management module is configured to select a correctable raw bit error rate limit from a plurality of raw bit error rate limits by changing a code-rate used by the encoder, wherein a virtual change to the decoder and the encoder occur to change the code rate.

Memory controller and integrated circuit device for correcting errors in data read from memory cells

A nonvolatile memory storage controller is provided for delivering log likelihood ratios (LLRs) to a low-density parity check (LDPC) decoder for use in the decoding of an LDPC encoded codeword. The controller includes read circuitry for reading an LDPC encoded codeword stored in a nonvolatile memory storage module using a plurality of soft-decision reference voltages to provide a plurality of soft-decision bits representative of the codeword. The controller further includes a plurality of lifetime specific LLR look-up tables representative of the lifetime threshold voltage distribution of the memory storage module, wherein each of the plurality of lifetime specific LLR look-up tables comprises a plurality of LLRs representative of a specific point in the lifetime of the memory storage module for each of the plurality of soft-decision bits. The controller provides the LLRs from the appropriate LLR look-up table to an LDPC decoder for the subsequent decoding of the codeword.

System and method for lifetime specific LDPC decoding

A random noise generation module for generating noisy LLRs for testing an error correction circuit of a nonvolatile memory storage module. The random noise generation module includes a coefficient generator for generating one or a plurality of coefficients, each of the plurality of coefficients associated with one region of a plurality of regions defining a linear space proportionately divided according to an area under a probability distribution curve for a nonvolatile memory storage module. The random noise generation module further includes a linear random number generator for generating a linear random number and a comparator for comparing the linear random number to one or more of the plurality of coefficients to identify the region of the plurality of regions of the probability distribution curve in which the linear random number belongs to generate a noisy LLR for testing an error correction circuit of a nonvolatile memory storage module.

System and method for random noise generation

Apparatuses and methods for correcting errors in data read from memory cells of an integrated circuit device includes an encoder. The encoder is configured from a single parity check matrix and the encoder is configured to be virtually adjustable by setting a number of bits in the encoder to zero. A decoder is configured from the single parity check matrix and the decoder is configured to be virtually adjustable by setting a log-likelihood ratio (LLR) for a number of bits in the decoder to a strong value. A code-rate that the encoder and decoder uses can be changed by adjusting the number of bits in the encoder that are set to zero and the number of bits in the decoder that are set to the strong LLR value.

Apparatus and method for adjusting a correctable raw bit error rate limit in a memory system using strong log-likelihood (LLR) values

Systems and methods for correcting errors in data read from memory cells include a memory controller, which includes an encoder, and a decoder. The memory controller is configured to adjust a correctable raw bit error rate limit to correct different bit error rates occurring in data read from the memory cells. The correctable raw bit error rate limit is adjusted by switching the decoding between hard-decision decoding and soft-decision decoding, wherein a number of soft bits allocated for message values can be changed during soft-decision decoding. The correctable raw bit error rate is adjusted by changing the code-rate within the memory system while making virtual adjustments to the same encoder and decoder.

Apparatus and method based on LDPC codes for adjusting a correctable raw bit error rate limit in a memory system

A low-density parity check (LDPC) decoder is provided for decoding low-density parity check (LDPC) encoded data wherein a layer specific attenuation factor is provided for each layer of the LDPC parity check matrix. An attenuation factor matrix comprising a plurality of coefficients specifies the specific attenuation factor for each layer and each iteration of the decoding process. A check node processor performs check node processing for each layer of the parity check matrix associated with the LDPC encoded codeword utilizing the normalized layered min-sum algorithm wherein the attenuation factor of the min-sum algorithm is determined by the coefficients of the attenuation factor matrix.

Layer specific attenuation factor LDPC decoder

A low-density parity check (LDPC) decoder is provided for decoding low-density parity check (LDPC) encoded data wherein the processing order of the layers of the LDPC parity check matrix are rearranged during the decode process in an attempt to avoid error mechanisms brought about by the iterative nature of the LDPC belief propagation decoding process, such as stopping sets and trapping sets.

System and method for avoiding error mechanisms in layered iterative decoding

A low-density parity check (LDPC) decoder is provided that eliminates the need to calculate customized check node codeword estimates by considering the check node processor and the variable node processor as a single processer having a shared memory for storing common variables to be used during both the check node processing and the variable node processing of the iterative decoding method.

System and method for reduced memory storage in LDPC decoding

A low-density parity check (LDPC) decoder is provided for decoding low-density parity check (LDPC) encoded data wherein an adaptive check node approximation is performed at the check node processor utilizing the smallest magnitude log-likelihood ratio (LLR) and the second smallest magnitude log-likelihood ratio (LLR) to adapt to the current conditions at the check node.

System and method for adaptive check node approximation in LDPC decoding

A nonvolatile memory controller generates an error correction code for each data unit in a data stripe and generates a parity unit based on the data units of the data stripe. If a data unit of the data stripe has a number of data bit errors not exceeding the error correction capacity of the nonvolatile memory controller, the nonvolatile memory controller corrects any data bit errors in the data unit based on the error correction code of the data unit. Otherwise, if a data unit of the data stripe has a number of data bit error exceeding the error correction capacity of the nonvolatile memory controller, the nonvolatile memory controller recovers the data unit based on the other data units of the data stripe and the parity unit.

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San Jose, CA, United States of America

Christopher I W Norrie