Polar Code Rewriting for Flash Memory Without Block Erasure
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Solution Overview
Problem
Conventional flash memory devices require resource-intensive block erasure operations to change data values, which is inefficient in terms of time and electrical power consumption.
Innovation Solution
The development of block erasure-avoiding codes that encode binary digits in a way that once a memory cell value is changed from logic '0' to logic '1', it remains at '1' until a block erasure operation, allowing data to be stored and transferred without the need for frequent erasures, using non-linear polar codes and multicoding schemes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If block erasure operation is performed to change data values in flash memory, then data values can be changed from logic '1' to logic '0', but time consumption and electrical power consumption increase significantly
Solution Approach 1:
The invention divides the data storage into multiple codewords, where each codeword is stored in a separate memory cell. This segmentation allows individual bits to be flipped without requiring block erasure of entire groups, thus reducing time consumption while maintaining data value changing capability
Solution Approach 2:
The invention employs asymmetric coding schemes where the encoding and decoding processes are optimized for the specific constraints of flash memory. By using asymmetric error correction codes, the system can efficiently handle the asymmetric cost of bit flips (0→1 being cheaper than 1→0), thereby reducing overall time consumption for data operations
2Ease of operation
If block erasure operation is performed to change data values in flash memory, then data values can be changed from logic '1' to logic '0', but electrical power consumption increases significantly
Solution Approach 1:
By segmenting data into individual codewords stored in separate cells, the system enables targeted bit flips without powering up entire blocks for erasure operations. This significantly reduces electrical power consumption while preserving the ability to change data values
Solution Approach 2:
The invention changes the fundamental parameter of data representation by using codeword-based encoding schemes that are optimized for low-power operations. This allows the system to perform data value changes with minimal power expenditure by avoiding high-power block erasure operations
3Productivity
If conventional coding schemes are used in flash memory, then implementation is simpler, but data bit transfer rate and channel capacity are lower
Solution Approach 1:
The invention employs polar codes that serve multiple functions simultaneously: they provide error correction, enable efficient data encoding/decoding, and are optimized for the specific characteristics of flash memory channels. This multi-functionality increases data bit transfer rate while managing complexity through a unified coding framework
Solution Approach 2:
The invention replaces conventional mechanical/block-based erasure operations with a sophisticated coding/decoding system. By substituting the physical erasure mechanism with intelligent code-based error correction, the system achieves higher data bit transfer rates while the complexity is managed through algorithmic efficiency
Data Source
AI summary
Techniques are disclosed for generating codes for representation of data in memory devices that may avoid the block erasure operation in changing data values. Data values comprising binary digits (bits) can be encoded and decoded using the generated codes, referred to as codewords, such that the codewords may comprise a block erasure-avoiding code, in which the binary digits of a data message m can be encoded such that the encoded data message can be stored into multiple memory cells of a data device and, once a memory cell value is changed from a first logic value to a second logic value, the value of the memory cell may remain at the second logic value, regardless of subsequently received messages, until a block erasure operation on the memory cell. Similarly, a received data message comprising an input codeword, in which source data values of multiple binary digits have been encoded with the disclosed block erasure-avoiding code, can be decoded in the data device to recover an estimated source data message.