NVM Codeword Reconstruction Using Side-Channel LDPC Decoding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Reconstructing data from multiple failed dies in non-volatile memory (NVM) is less successful due to the inability to generate a reliable side channel for iterative decoding, as existing methods rely on XOR results from non-failed dies, which are insufficient when multiple dies fail.
Innovation Solution
Generating a side channel using a combination of hard and soft outputs from successful and unsuccessful decoding attempts on non-failed and failed dies, respectively, to input into an iterative decoder for reconstructing codewords on failed dies, thereby overcoming the limitations of XOR-based reconstruction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If XOR-based reconstruction is used for single die failure, then data recovery is successful, but reconstruction fails when multiple dies fail due to insufficient side channel information
Solution Approach 1:
The patent performs preliminary decoding attempts on all non-failed dies before attempting reconstruction. These preliminary actions generate soft output information that is stored and later used as side channel information for the actual reconstruction process, enabling successful recovery even when multiple dies fail.
Solution Approach 2:
The patent introduces soft output information as an intermediary element between the failed dies and the reconstruction process. This side channel information acts as a mediator that carries useful decoding insights from non-failed dies to assist in reconstructing data from multiple failed dies, overcoming the limitations of direct XOR-based reconstruction.
2Loss of information
If iterative decoding is performed multiple times on failed dies, then more side channel information is generated, but decoding complexity and processing time increase
Solution Approach 1:
The patent extracts only the necessary soft output information from the iterative decoding process without requiring complete successful decoding. By taking out the useful side channel information early in the process and using it for reconstruction, the method avoids the need for multiple complete decoding iterations, thereby reducing complexity while maintaining information availability.
Solution Approach 2:
The patent performs partial decoding attempts on non-failed dies - enough to generate useful soft output information but not necessarily completing full successful decoding for all dies. This partial action provides sufficient side channel information for reconstruction while avoiding the excessive processing that would result from requiring complete decoding of all dies first.
Data Source
AI summary
Embodiments of the present disclosure describe device, methods, computer-readable media and system configurations for decoding codewords using a side channel. In various embodiments, a memory controller may be configured to determine that m of n die of non-volatile memory (“NVM”) have failed iterative decoding. In various embodiments, the memory controller may be further configured to generate a side channel from n-m non-failed die and the m failed die other than a first failed die. In various embodiments, the memory controller may be further configured to reconstruct, using iterative decoding, a codeword stored on the first failed die of the m failed die based on the generated side channel and on soft input to an attempt to iteratively decode data stored on the first failed die. In various embodiments, the iterative decoding may include low-density parity-check decoding. Other embodiments may be described and/or claimed.