Memory Controller Cross-Coupling Interference Cancellation
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Solution Overview
Problem
Existing memory systems face challenges in effectively canceling cross-coupling interference among memory cells, which leads to read errors and performance degradation, especially in three-dimensional configurations where memory cells are closely organized, and current CCI cancellation features are insufficient in removing interference from multiple neighbor cells.
Innovation Solution
A memory controller is designed to estimate and cancel cross-coupling interference by calculating Cross-Coupling Coefficients (CCFs) that model the interference caused by neighbor memory cells, using observation samples from target and neighbor memory cells, and applying these coefficients to produce enhanced readout samples that minimize square distances, thereby reducing CCI effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If memory cells are organized in three-dimensional configurations with close spacing, then storage capacity increases, but cross-coupling interference among memory cells increases
Solution Approach 1:
The patent introduces an intermediary cancellation signal that represents the estimated cross-coupling interference from neighbor memory cells. This cancellation signal is generated based on observed neighbor cell values and applied to the target cell readout to抵消 the harmful interference, enabling reliable reading in densely packed three-dimensional memory configurations
Solution Approach 2:
The system employs feedback by observing the actual values in neighbor memory cells and using this information to generate appropriate cancellation signals. The controller continuously monitors neighbor cell states and adjusts the cancellation signals accordingly, creating a closed-loop system that adapts to changing interference conditions
2Object-affected harmful factors
If conventional CCI cancellation techniques are used, then some interference is reduced, but interference from multiple neighbor cells cannot be effectively removed
Solution Approach 1:
The patent segments the interference cancellation process by treating each neighbor memory cell independently. The controller identifies individual neighbor cells, estimates their respective interference contributions separately, and generates distinct cancellation signals for each, allowing effective handling of multiple interferers simultaneously
Solution Approach 2:
The cancellation signal generation mechanism is designed to be universal and adaptable to any number of neighbor cells. The same basic approach of observing neighbor values and generating cancellation signals works regardless of how many neighbor cells are present, making the solution versatile for different memory configurations
3Ease of operation
If cross-coupling interference is not canceled, then read operations are simpler, but read errors increase and performance degrades
Solution Approach 1:
The system performs self-service by automatically generating and applying cancellation signals without requiring external intervention. The memory controller autonomously observes neighbor cell values, estimates interference, generates cancellation signals, and applies them to the target cell readout, maintaining both simplicity and reliability
Data Source
AI summary
A memory controller includes an interface and a processor. The interface communicates with memory cells that store data in predefined Programming Voltages (PVs). The processor is configured to produce observation samples that each includes (i) a target sample read from a target memory cell in a target Word Line (WL), and (ii) neighbor samples read from neighbor memory cells. Based on the observation samples, the processor is further configured to jointly estimate Cross-Coupling Coefficients (CCFs), by searching for CCFs that aim to minimize a predefined function of distances calculated between transformed observation samples that have been transformed using the CCFs and combinations of PVs that are closest to the respective transformed observation samples, to apply, based on the CCFs, cross-coupling cancelation to readout samples retrieved from the memory cells to produce enhanced readout samples, and to perform a storage operation related to reading data, using the enhanced readout samples.