Polar List Decoder Early Termination Using Spread Metrics
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Solution Overview
Problem
Existing early-termination techniques for polar list decoders in wireless communication systems face challenges in differentiating when to terminate decoding processes to conserve power without prematurely stopping successful decodings, often increasing decoding complexity and reducing benefits.
Innovation Solution
A method that determines whether to terminate the decoding process based on a spread metric calculated from path metrics associated with decoding path candidates, comparing it to a threshold to decide on early termination before or after completing the cyclic redundancy check (CRC) or list decoding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If early termination is implemented to reduce power consumption, then energy efficiency improves, but false alarm rate increases due to premature termination of successful decodings
Solution Approach 1:
The patent implements feedback by continuously monitoring the spread metric during the decoding process and using this information to dynamically adjust the decoding continuation decision. The spread metric provides real-time feedback about the convergence state of path metrics, enabling the system to distinguish between legitimate decoding failures and successful decodings, thereby reducing false alarms while maintaining power savings.
Solution Approach 2:
The patent changes the parameter being monitored from simple path metric values to the spread metric (difference between maximum and minimum path metrics). This parameter transformation enables more accurate detection of decoding failure conditions, allowing the system to terminate early with higher confidence and reduce false alarm rates while still achieving power consumption benefits.
2Use of energy by moving object
If existing early-termination techniques are used, then power consumption reduces, but decoding complexity increases
Solution Approach 1:
The patent extracts only the essential information needed for early termination decision-making by focusing solely on the spread metric (difference between max and min path metrics) rather than analyzing all path metric details. This extraction approach reduces computational complexity while maintaining the power-saving benefits of early termination.
Solution Approach 2:
The patent performs a partial analysis by calculating only the spread metric rather than进行全面 path metric analysis. This partial action is sufficient to detect decoding failures and enable early termination, reducing complexity while still achieving the desired power consumption reduction.
3Reliability
If decoding continues to completion to ensure accuracy, then false alarm rate decreases, but decoding latency increases
Solution Approach 1:
The patent performs preliminary monitoring of the spread metric during the decoding process to identify decoding failures before completion. This preliminary detection action allows the system to terminate early when failures are detected, reducing latency for failed decodings while maintaining accuracy for successful decodings through the reliability of the spread metric criterion.
Solution Approach 2:
The patent implements dynamic early termination by continuously evaluating the spread metric throughout the decoding process rather than using a static termination rule. This dynamic approach allows the system to adaptively terminate early when decoding failures are detected, reducing latency, while continuing to completion when successful decoding is likely, maintaining low false alarm rates.
Data Source
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.