Polar SCL Decoder Special-Node Processing for Lower Latency
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Solution Overview
Problem
Conventional successive cancellation (SC) and simplified successive cancellation list (SCL) decoding methods for polar codes suffer from high latency, which limits their practical applications, and lack a well-established logic for determining path splitting in special nodes, leading to potential performance degradation.
Innovation Solution
An apparatus and method for constituent code processing in polar SCL decoding that determines the number of candidate paths and their metrics, selecting the most probable paths based on path metrics to improve decoding efficiency and reduce latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If conventional successive cancellation (SC) and simplified successive cancellation list (SCL) decoding methods are used, then the decoding process is simple to implement, but the latency is high which limits practical applications
Solution Approach 1:
The patent segments the polar code decoding process by identifying and separately processing special nodes (constituent codes) from general nodes. Special nodes are detected based on their constituent code properties, and a dedicated processing path is applied to them, while general nodes follow the conventional SCL decoding path. This segmentation allows latency reduction in special nodes without increasing overall decoder complexity.
Solution Approach 2:
The patent applies local quality by implementing different processing strategies for different types of nodes within the same decoding framework. Special nodes receive optimized processing with simplified path metric calculations and candidate path selection, while general nodes maintain the full SCL decoding process. This localized optimization reduces overall latency without compromising the reliability of general node decoding.
2Reliability
If path splitting in special nodes is not well-established, then the decoder structure remains simple, but performance degradation occurs
Solution Approach 1:
The patent applies preliminary action by pre-determining the processing strategy for special nodes based on their constituent code type. The decoder identifies special nodes and pre-calculates the appropriate number of candidate paths and path metric update rules before actual decoding occurs. This preliminary preparation ensures optimal performance without requiring complex real-time decisions during decoding.
Solution Approach 2:
The patent changes parameters specifically for special node processing, including the number of candidate paths maintained, the path metric calculation method, and the splitting behavior. These parameter changes are applied selectively to special nodes based on their constituent code properties, improving decoding performance without affecting the overall decoder architecture or general node processing.
3Productivity
If there is no differentiation within each special node type, then the processing logic is simplified, but the different polarization features of special nodes are not captured
Solution Approach 1:
The patent implements local quality by differentiating processing within special node types based on their specific polarization features and constituent code properties. Each special node type (e.g., Rate-0, Rate-1, Repetition, Single Parity Check) receives tailored processing parameters such as candidate path counts and metric update rules, maximizing decoding efficiency for each node type without requiring complex universal processing logic.
Data Source
AI summary
An apparatus and a method for constituent code processing in polar successive cancellation list (SCL) decoding and a method thereof. The apparatus includes a processor configured to determine a number of r candidate paths, wherein r is an integer; determine path metrics PMt<sub2>j </sub2>of a codeword j for each candidate path t; and select r most probable paths based on the path metrics PMt<sub2>j</sub2>. The method includes determining q indicies min1, min2, . . . , minq of least reliable bits in the constituent code, wherein q is a number; determining a number of r candidate paths, wherein r is an integer; determining path metrics PMt<sub2>j </sub2>of a codeword j for each candidate path t; and selecting r most probable paths based on the path metrics PMt<sub2>j</sub2>.