SCL Decoder Buffer Updates for Low-Latency Path Sorting
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Solution Overview
Problem
Current Successive Cancellation List (SCL) decoders face inefficiencies due to high latency and processing overhead from extensive data copying and sorting operations, which hinder their performance in decoding large block sizes and competing with Turbo or Low Density Parity Check (LDPC) Codes in bit error performance.
Innovation Solution
The proposed solution involves selective replacement and deferred update techniques to optimize buffer management by limiting LLR updates to changed statistics and performing in-place calculations, reducing the need for extensive data copying and sorting, thereby improving computational efficiency and reducing latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional SCL decoder updates entire rows in the buffer based on path metrics, then path metric accuracy is maintained, but data transfer overhead and processing latency increase significantly
Solution Approach 1:
The patent extracts and updates only the changed statistics (specific LLR values) rather than updating entire rows. The buffer management selectively identifies and updates only those path metric entries that have changed since the previous update cycle, eliminating unnecessary data transfers and processing of unchanged values.
Solution Approach 2:
The patent segments the buffer update operation into selective updates of individual changed statistics versus complete row updates. By dividing the update process into granular selective updates, the system reduces the volume of data transferred and processed while maintaining accuracy for only those values that have actually changed.
2Reliability
If SCL decoder performs extensive data copying and sorting operations, then decoding accuracy is improved, but computational complexity and processing time increase
Solution Approach 1:
The patent applies partial action by performing sorting and data copying only on the subset of changed statistics rather than on all buffer data. The selective replacement mechanism identifies only the necessary portion of data that requires sorting and copying, reducing computational complexity while maintaining decoding accuracy.
Solution Approach 2:
The patent performs preliminary identification of changed statistics before executing sorting and copying operations. By pre-identifying which buffer entries have changed, the system prepares a minimized dataset for subsequent sorting and copying, reducing overall computational complexity.
3Stability of the object's composition
If SCL decoder copies input statistics to predetermined buffer locations before LLR updates, then data integrity is ensured, but processing speed decreases due to sequential operations
Solution Approach 1:
The patent enables continuous processing by performing LLR updates in-place without requiring preliminary copying to predetermined locations. The selective replacement mechanism allows the decoder to continue processing with updated values immediately, eliminating idle time associated with sequential copy operations while maintaining data integrity through controlled update sequences.
Solution Approach 2:
The patent inverts the conventional sequence by updating LLR values in-place directly in the buffer rather than copying data first and then updating. This reversal of the operation sequence eliminates the copying step entirely for unchanged values, improving processing speed while maintaining data integrity through the selective update mechanism.
Data Source
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AI summary
Various embodiments are described of a system and method for improved SCL decoder operation. In particular, various embodiments are described which improve the efficiency of the buffer management based on updated path metric statistics. In some embodiments, the SCL decoder may perform selective replacement to limit the extent of LLR updates per row only to the statistics that have changed since the previous update cycle. In some embodiments, the SCL decoder may perform deferred updates, which may involves in-place calculation of both û φ = 0 and û φ = 1 bit estimate (LLR) updates based on the row from which the updated row will be derived.