Polar List Decoding Early Termination Using Spread Metrics
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Solution Overview
Problem
Existing wireless communication systems face challenges in differentiating when early termination of polar list decoders is appropriate, leading to increased decoding complexity and power consumption, especially in cases where decoding may still be successful.
Innovation Solution
A wireless device calculates a spread metric based on the range of path metrics across multiple decoding paths and compares it to a threshold, allowing for early termination of the decoding process when the spread metric is below a certain threshold, thereby reducing processing overhead and improving latency and false alarm reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If early termination is applied to polar list decoders, then decoding latency and power consumption are reduced, but false alarm reliability deteriorates due to inability to accurately differentiate unsuccessful decoding attempts
Solution Approach 1:
The patent replaces the conventional early termination mechanism (which relies on simple path metric thresholds) with a statistical hypothesis testing framework. This substitution introduces a more sophisticated decision-making system that calculates spread metrics and compares them against dynamically determined thresholds based on desired false alarm probabilities, thereby maintaining reliability while enabling early termination.
Solution Approach 2:
The patent dynamically adjusts the termination threshold parameter based on the desired false alarm probability. By changing the threshold parameter according to different reliability requirements, the system can adaptively balance between early termination benefits and false alarm control, allowing flexible optimization for different operating conditions.
2Productivity
If conventional early termination criteria are used, then processing overhead is reduced, but decoding complexity increases due to inability to accurately identify unsuccessful decoding attempts
Solution Approach 1:
The patent replaces ad-hoc early termination heuristics with a systematic statistical hypothesis testing approach. This substitution provides a clear mathematical framework for determining when to terminate decoding, reducing the need for complex heuristic logic while maintaining accurate identification of unsuccessful decoding attempts.
Solution Approach 2:
The patent implements feedback mechanisms where the spread metric calculations and hypothesis test results inform the termination decision. This feedback loop allows the system to continuously assess decoding success probability and adjust termination decisions accordingly, simplifying the overall control logic while improving accuracy.
Data Source
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AI summary
Methods, systems, and devices for wireless communication are described. In a new radio (NR) system, a wireless device may identify a candidate codeword for a channel employing polar coding. The wireless device may perform a decoding operation on the candidate codeword to determine candidate decoding paths corresponding to encoded information bits. The decoding operation may include multiple decoding path candidates, each of which is associated with a path metric. The wireless device may evaluate a spread metric to determine if a decoding hypothesis is incorrect or if the received codeword is too corrupted for decoding. The spread metric may be based on the path metrics of the decoding paths or soft metrics of the decoding paths determined based on a subset of bit channels of the polar code. The wireless device may normalize the spread metric to compensate for signal-to-noise ratio (SNR) variation.