Multi-Level Cell Flash Memory Cross-Page Sector Storage
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Solution Overview
Problem
Existing multi-level cell flash memory devices face challenges with high error rates, limited storage capacity, and inflexible read/write access techniques, particularly in managing multiple sectors across pages and varying code rates.
Innovation Solution
The implementation of cross-page sector storage, multi-page coding, and per-page coding techniques, allowing for variable code rates and decoding schemes, enables efficient storage and retrieval of data by treating each page as a unique unit with customizable encoding and decoding parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multi-level cell flash memory devices store two or more bits per memory cell by dividing the operating range into multiple threshold levels, then storage capacity is increased, but reliability of individual bits deteriorates due to smaller state ranges and higher error rates
Solution Approach 1:
The patent divides the flash memory into multiple pages, with each page storing a portion of sectors. This segmentation allows independent encoding and error correction for each page, improving reliability while maintaining high storage capacity. Each page can be managed separately with its own code rate, preventing error propagation across the entire memory space.
Solution Approach 2:
The patent applies different code rates to different pages based on their specific requirements. Each page can have customized encoding parameters tailored to its data importance and error susceptibility. This local optimization allows critical data to receive stronger error protection while less critical data uses lighter encoding, overall improving system reliability without sacrificing storage efficiency.
2Device complexity
If existing flash devices use page level access techniques where pages are written and read independently with the same code and code rate, then device complexity is reduced, but adaptability to different data requirements deteriorates
Solution Approach 1:
The patent introduces dynamic code rate selection for each page, allowing the encoding parameters to be adjusted based on data requirements. The system can selectively apply different code rates to different pages within the same memory device, providing adaptability while maintaining manageable complexity through systematic page-level organization.
Solution Approach 2:
The patent changes the coding parameters (code rate, encoding scheme) on a per-page basis rather than applying a uniform code to all pages. This parameter variation allows optimization for different data types and importance levels, enhancing adaptability while the page structure keeps the complexity manageable through modular processing.
3Device complexity
If one page comprises eight sectors of user information and a full page is read to retrieve a single sector, then device complexity is simplified with uniform page structure, but loss of time increases due to reading unnecessary data
Solution Approach 1:
The patent segments the page into distinct sectors with clear boundaries and metadata markers. This segmentation enables the system to identify and retrieve only the specific sector containing the desired data, rather than reading the entire page. The sector-level addressing and identification structures allow rapid localization of data within the page, reducing retrieval time while maintaining simple page organization.
4Ease of operation
If multi-level cell flash memory devices employ the same code and code rate for all pages, then ease of operation is improved with uniform encoding, but reliability deteriorates due to inability to optimize for different data requirements
Solution Approach 1:
The patent applies different code rates and encoding schemes to different pages based on their specific data requirements. Each page can be independently configured with optimal error correction parameters, improving overall data integrity. The page-level encoding flexibility allows critical data to receive stronger protection while maintaining ease of operation through systematic management of encoding parameters.
Data Source
AI summary
Methods and apparatus are provided for storing data in a multi-level cell flash memory device with cross-page sectors, multi-page coding and per-page coding. A single sector can be stored across a plurality of pages in the flash memory device. Per-page control is provided of the number of sectors in each page, as well the code and/or code rate used for encoding and decoding a given page, and the decoder or decoding algorithm used for decoding a given page. Multi-page and wordline level access schemes are also provided.