Receiver LLR Sign Adjustment for Faster, More Reliable Decoding
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Solution Overview
Problem
Existing receivers in wireless communication systems face challenges in achieving accurate and rapid decoding of signals due to inconsistencies in the signs of log likelihood ratios, which affect decoding performance when they differ, leading to unreliable decoding results.
Innovation Solution
A receiver is configured to adjust the extrinsic log likelihood ratio by comparing its sign with a reference value, applying scaled values based on the comparison, and generating priori log likelihood ratios to improve decoding accuracy and speed by stabilizing the sign changes in the extrinsic log likelihood ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the receiver uses standard log likelihood ratio generation without sign adjustment, then the decoding process is simpler, but the decoding accuracy deteriorates when signs of log likelihood ratios differ
Solution Approach 1:
The patent applies preliminary action by adjusting the sign of the extrinsic log likelihood ratio before it is used in subsequent decoding operations. The sign adjustment is performed in advance based on comparison with a reference value, ensuring that the log likelihood ratio has the correct sign orientation before participating in the decoding process, thereby preventing accuracy deterioration without requiring complex post-processing corrections
Solution Approach 2:
The patent changes the parameter of the log likelihood ratio by adjusting its sign based on a comparison with a reference value. When the sign of the extrinsic log likelihood ratio differs from the reference value, the patent applies a scaled value to flip or adjust the sign, transforming the parameter state to ensure consistency and improve decoding accuracy while maintaining relatively simple operational complexity
2Productivity
If the receiver repeatedly generates log likelihood ratios without sign stabilization, then more decoding iterations are performed, but the decoding speed decreases due to inconsistent signs
Solution Approach 1:
The patent implements feedback by comparing the sign of the extrinsic log likelihood ratio with a reference value and using this comparison result to determine the sign adjustment. This feedback mechanism ensures that the log likelihood ratio maintains consistent sign orientation across iterations, enabling the decoder to converge faster and improving decoding speed while maintaining reliable decoding results
Solution Approach 2:
By performing sign adjustment in advance before each decoding iteration, the patent prevents inconsistent signs from causing unnecessary iterative repetitions. The preliminary sign stabilization ensures that each decoding iteration progresses toward convergence efficiently, thereby improving decoding speed without sacrificing reliability
3Measurement precision
If the receiver applies sign adjustment to extrinsic log likelihood ratio, then decoding accuracy improves, but the processing complexity increases
Solution Approach 1:
The patent applies local quality by performing sign adjustment only on the extrinsic log likelihood ratio where it is most needed, rather than processing all log likelihood ratios uniformly. The adjustment is localized to specific components of the decoding process where sign consistency has the greatest impact on accuracy, thereby improving decoding accuracy while minimizing the increase in processing complexity
Data Source
AI summary
A receiver configured to receive a signal may include a symbol, the receiver may include: at least one memory storing instructions; and at least one processor configured to execute the instructions to: generate a first posteriori log likelihood ratio corresponding to a bit in the symbol based on a channel log likelihood ratio corresponding to the bit; apply a first scaled value to a first extrinsic log likelihood ratio in the first posteriori log likelihood ratio; generate a first priori log likelihood ratio by selectively using a first reference value based on a comparison result; generate a second posteriori log likelihood ratio corresponding to the bit based on the first priori log likelihood ratio and the channel log likelihood ratio; and decode the signal based on the second posteriori log likelihood ratio.