Bit Flipping Decoder Criteria for Latency-Error Rate Balance
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Solution Overview
Problem
Bit flipping decoders used in memory subsystems face a trade-off between latency and error correction capability, with fixed criteria leading to variable performance across different bit error rates, resulting in either high latency or high codeword error rates.
Innovation Solution
A dynamic bit flipping criterion is introduced, adjusting the aggressiveness of bit flipping based on estimated bit error rates, using syndrome information from the decoding process to set more aggressive criteria at low error rates and less aggressive criteria at high error rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If fixed bit flipping criteria are used, then decoder implementation is simple, but performance varies with bit error rate resulting in high latency or high codeword error rates
Solution Approach 1:
The patent implements dynamic bit flipping criteria that adapt based on the estimated bit error rate. The decoder transitions from fixed criteria to dynamic criteria where the bit flipping threshold is adjusted according to channel conditions, allowing the system to optimize performance across varying error rates while maintaining reasonable implementation complexity through structured adaptation mechanisms.
2Loss of time
If aggressive bit flipping criteria are used, then decoder latency is reduced, but codeword error rate increases
Solution Approach 1:
The patent changes the bit flipping threshold parameter dynamically based on estimated bit error rate. When error rate is low, more aggressive criteria (lower threshold) are applied to reduce latency. When error rate is high, less aggressive criteria (higher threshold) are applied to maintain reliability. This parameter adaptation resolves the contradiction between speed and accuracy.
Solution Approach 2:
The system uses feedback from syndrome information to estimate bit error rate and adjust bit flipping criteria accordingly. The decoder monitors decoding progress and channel conditions, then adapts its flipping threshold in response, creating a closed-loop system that balances latency and error rate based on real-time conditions.
3Reliability
If less aggressive bit flipping criteria are used, then codeword error rate is reduced, but decoder latency increases
Solution Approach 1:
The patent implements parameter changes in the opposite direction from the previous contradiction. When bit error rate is estimated to be high, the system adopts less aggressive criteria (higher threshold) to reduce codeword error rate, accepting increased latency as necessary for reliability. When error rate is low, the system switches to aggressive criteria to minimize latency. This dynamic adjustment resolves the trade-off.
Data Source
AI summary
Methods, systems, and apparatuses include receiving a codeword stored in a memory device. Syndrome information and energy function values are determined for bits of the codeword. A bit flipping criterion is selected using the syndrome information from a plurality of values. A bit of the codeword is flipped when the energy function values for a bit of the codeword satisfies the bit flipping criterion. A corrected codeword that results from the flipping of the bits is returned.