Polar Decoder Feedback Architecture for Lower Bit-Update Latency
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Solution Overview
Problem
Conventional bit feedback mechanisms in polar decoding are computationally complex and resource intensive, leading to latency issues in wireless communication systems.
Innovation Solution
A distributed feedback architecture for polar decoding that stores a single state map and bit arrays in memory for each layer, reducing resource usage by updating states only when necessary and sending state maps between layers after completion of sub-decoder invocations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional bit feedback mechanisms are used in polar decoding, then decoding accuracy is maintained, but computational complexity and resource usage increase significantly
Solution Approach 1:
The patent segments the bit feedback mechanism into two distinct components: a compressed state map that tracks path permutations and a separate bit array that stores actual bit values. This segmentation allows the system to maintain decoding accuracy through the state map while reducing computational complexity by only updating the compressed representation rather than all individual bits across all paths.
Solution Approach 2:
The patent creates a compressed copy (state map) of the path permutation information instead of maintaining and updating all original bit feedback data. This copy contains only the essential permutation indices needed to reconstruct the correct bit assignments, significantly reducing the computational burden while preserving decoding accuracy.
2Reliability
If conventional bit feedback mechanisms are used in polar decoding, then decoding accuracy is maintained, but resource consumption increases
Solution Approach 1:
The patent segments the feedback data structure into a compact state map storing only permutation indices and a separate bit array. This segmentation reduces the quantity of data that needs to be stored and transmitted between decoding layers, thereby reducing resource consumption while maintaining the ability to accurately reconstruct decoded bits.
Solution Approach 2:
The patent changes the parameter representation from storing all individual bit values to storing compressed permutation indices in the state map. This parameter transformation reduces the amount of memory and computational resources required while preserving the essential information needed for accurate decoding.
3Reliability
If conventional bit feedback mechanisms are used in polar decoding, then complete path tracking is achieved, but latency increases
Solution Approach 1:
The patent segments the feedback update process into selective updates of the compressed state map based on where path permutations actually occur, rather than updating all bits at every layer. This segmentation enables the system to maintain accurate path tracking while minimizing the time spent on feedback operations, thereby reducing decoding latency.
4Reliability
If bit updating is performed at each layer during decoding, then path information is maintained, but complexity and latency increase
Solution Approach 1:
The patent segments the update operation to occur only at specific points in the decoding process where path permutations are detected, rather than at every layer. The compressed state map allows the system to maintain accurate path information by tracking only the necessary permutation changes, reducing update complexity while preserving path information accuracy.
Data Source
AI summary
A wireless device may decode a polar coded codeword using a successive cancellation list (SCL) decoder. The decoder may implement a distributed feedback architecture, where the decoder stores one or more state maps and a set of bit arrays in memory for each layer of decoding. For different phases of decoding in a layer, the decoder may update the state maps and sets of bit arrays to limit the resources used. Additionally, when performing bit updating following the decoding of a bit of the codeword, the decoder may not update each layer of the decoding process. Instead, each sub-decoder may send a state map up to the calling layer for bit updating when the sub-decoder has completed its invocation, and may not return any intermediate state maps prior to completing invocation. Thus, each decoder and sub-decoder may perform bit updating just twice, reducing the complexity and latency of decoding.