NAND Wordline Codeword Partitioning for Faster, Lower-Error Programming
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Solution Overview
Problem
Conventional NAND Flash memory systems face inefficiencies in the programming step and varying error rates across different pages, leading to increased time and complexity in data storage and retrieval.
Innovation Solution
The method involves reformulating codewords into partitions and storing them across different pages or Logical Unit Numbers (LUNs, using a chopping logic controller, extra buffer, or permutor to optimize data distribution and reduce error rates by averaging Raw Bit Error Rates (RBER) across pages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If codewords are stored sequentially in the page register and transferred to NAND memory in one step, then the storage process is simple, but the programming step becomes time-consuming and complex
Solution Approach 1:
The patent divides each codeword into multiple partitions (e.g., first partition and second partition) and distributes them across different pages in the NAND memory. This segmentation allows parallel programming operations and reduces the time required for the programming step while maintaining manageable complexity through systematic organization of data partitions.
2Reliability
If all codewords are stored in the same page, then the storage structure is simple, but error rates vary significantly across different pages
Solution Approach 1:
The patent applies local quality by distributing different partitions of codewords to different pages based on their specific error rate characteristics. Each page receives data partitions that are optimized for its error profile, thereby improving overall reliability by matching data placement with page-specific quality characteristics rather than using a uniform storage approach.
Solution Approach 2:
The patent transitions from a single-dimension storage approach (all codewords in one page) to a multi-dimensional approach by distributing partitions across multiple pages. This dimensional expansion allows the system to exploit variations in error rates across different pages, improving reliability through diversified data placement strategies.
3Loss of time
If the entire first codeword is stored before the second codeword in the page register, then the buffering process is straightforward, but the programming time increases
Solution Approach 1:
The patent performs preliminary actions by partitioning codewords and pre-positioning them in the buffer memory in a distributed manner across different pages before the actual programming operation. This preliminary organization enables parallel programming execution and reduces the overall programming time, while the buffer management complexity is handled through systematic partitioning rules.
Data Source
AI summary
Systems and methods are disclosed for storing codewords in NAND memory. The method includes receiving a first and second codeword. The method includes storing a partition of the first codeword and a partition of the second codeword in a buffer. The method includes transferring the partition of the first codeword and the partition of the second codeword to a page in NAND memory.