Adaptive SCL Polar Decoder With Dynamic List Size Control
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Solution Overview
Problem
Current successive cancellation list (SCL) decoders for wireless communications face challenges in balancing latency and error-correction performance, particularly for large block lengths, where implementation complexity and resource overhead are high, and existing methods do not efficiently manage list size to optimize decoding efficiency.
Innovation Solution
A method is introduced to dynamically change the list size of the SCL decoder based on differential path metric thresholds, allowing for adaptive list size adjustment at each decoding stage to maintain sensitivity and balance latency and error-correction performance, by comparing median and lowest path metrics and adjusting the number of paths accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed large list size is used in SCL decoder to improve error-correction performance, then decoding sensitivity is improved, but latency and implementation complexity increase significantly
Solution Approach 1:
The patent applies dynamics by making the list size adaptive rather than fixed. The list size L is dynamically adjusted at each decoding stage based on the differential path metric threshold and current path metrics. This allows the decoder to use larger list sizes when error-correction performance is critical and smaller list sizes when latency is more important, resolving the contradiction between reliability and time loss.
Solution Approach 2:
The patent changes the parameter of list size from a static value to a dynamic value that varies with decoding stage and channel conditions. By computing the differential path metric threshold and comparing it with current path metrics, the system adaptively selects the appropriate list size, thereby optimizing both error-correction performance and latency according to actual decoding needs.
2Reliability
If a fixed large list size is used in SCL decoder to maintain decoding sensitivity, then error-correction performance is improved, but implementation complexity and resource overhead increase
Solution Approach 1:
The patent makes the list size dynamic based on actual decoding needs rather than using a fixed large value. The differential path metric threshold computation and comparison mechanism enables the decoder to use only the necessary number of paths at each stage, reducing implementation complexity while maintaining decoding sensitivity when needed.
Solution Approach 2:
The list size parameter is changed from a fixed large value to an adaptive parameter that adjusts according to the differential path metric threshold and current path metrics. This parameter change reduces the average list size and associated computational complexity while preserving decoding sensitivity in critical scenarios.
3Reliability
If a fixed large list size is used in SCL decoder, then error-correction performance is maintained, but resource overhead such as silicon area and PCB real-estate increase
Solution Approach 1:
The patent applies dynamics by making the list size adaptive rather than fixed. The resource requirements (silicon area, PCB real-estate) are directly related to the list size. By dynamically adjusting the list size based on the differential path metric threshold and current path metrics, the system reduces average resource usage while maintaining error-correction performance when needed.
Solution Approach 2:
The list size parameter is dynamically changed based on decoding stage and channel conditions. This parameter change directly reduces the average resource overhead (silicon area, PCB real-estate) required for the decoder while preserving error-correction performance in scenarios where it is critical.
4Device complexity
If sequential bit estimation is performed in SC decoder to maintain simplicity, then implementation complexity is reduced, but latency increases for large block lengths
Solution Approach 1:
The patent applies dynamics by making the list size adaptive rather than fixed. The list size L is dynamically adjusted at each decoding stage based on the differential path metric threshold and current path metrics. This allows the decoder to use larger list sizes when error-correction performance is critical and smaller list sizes when latency is more important, resolving the contradiction between reliability and time loss.
Solution Approach 2:
The patent changes the parameter of list size from a static value to a dynamic value that varies with decoding stage and channel conditions. By computing the differential path metric threshold and comparing it with current path metrics, the system adaptively selects the appropriate list size, thereby optimizing both error-correction performance and latency according to actual decoding needs.
Data Source
AI summary
A method of dynamically changing the list size of a successive cancellation list (SCL) decoder, the SCL decoder arranged to decode data received from a wireless communications system, the method comprising at each successive cancellation stage of the SCL decoder, determining a path metric of each path of the SCL decoder, selecting a differential path metric threshold, and dynamically changing the list size of the SCL decoder based on the differential path metric threshold and the path metric of each path of the cancellation stage, such that decoding sensitivity of the decoder is maintained and/or latency and error-correction performance of the decoder are balanced.