PAC Fano Decoding with Thresholded LLR Bit Decisions
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Solution Overview
Problem
In 6G wireless communication systems, the high latency and high block error rate (BLER) associated with polarization-adjusted convolutional (PAC) Fano decoding are significant challenges due to frequent reliability tests, which are necessary for decoding multiple information bits in a search tree manner.
Innovation Solution
A method and apparatus for a receiving node in a wireless communication system that estimates bit values of information bits based on log-likelihood ratios (LLRs), determining bit values by comparing reliability values with thresholds, reducing the need for frequent reliability tests and thereby minimizing latency and BLER.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If frequent reliability tests are performed during PAC Fano decoding, then decoding accuracy is improved, but latency increases
Solution Approach 1:
The patent segments the reliability test process by identifying specific decision points in the Fano decoding algorithm where reliability tests are performed. By dividing the decoding process into stages and applying reliability tests only at critical decision points rather than continuously, the system maintains decoding accuracy while reducing the frequency of tests, thereby lowering latency.
Solution Approach 2:
The patent applies partial reliability testing by performing reliability tests only when necessary during the Fano decoding process, rather than at every step. This selective approach uses sufficient (but not excessive) reliability checks to maintain decoding accuracy while avoiding unnecessary tests that would increase latency.
2Reliability
If frequent reliability tests are performed during PAC Fano decoding, then decoding accuracy is improved, but processing speed decreases
Solution Approach 1:
The patent segments the decoding process to identify critical decision points where reliability tests provide maximum benefit. By applying reliability tests only at these segmented points rather than uniformly throughout the process, the system maintains low block error rates while minimizing the impact on processing speed.
Solution Approach 2:
The patent dynamically adjusts the reliability test threshold parameter during the Fano decoding process. By changing the threshold parameter based on the current decoding state and LLR values, the system optimizes the balance between maintaining decoding accuracy (low BLER) and preserving processing speed, performing tests only when the parameter conditions warrant them.
3Loss of time
If threshold comparison method is used to determine bit values, then latency is reduced, but decoding complexity changes
Solution Approach 1:
The patent extracts and removes unnecessary reliability test operations from the Fano decoding algorithm, keeping only the essential threshold comparison operations. By taking out the excessive complexity of frequent reliability tests and retaining only the critical threshold comparisons at key decision points, the system reduces latency while managing decoding complexity effectively.
Solution Approach 2:
The patent employs simple threshold comparison operations as lightweight, disposable decision-making mechanisms during decoding. These simple comparisons serve as efficient substitutes for complex reliability tests, providing sufficient decoding performance with minimal computational overhead and reduced latency.
Data Source
AI summary
The present disclosure relates to a 5G communication system or a 6G communication system for supporting higher data rates beyond a 4G communication system such as long term evolution (LTE). A method performed by a receiving node in a wireless communication system is provided. The method comprises receiving, from a transmitting node, a codeword comprising at least one information bit, estimating a bit value of a first information bit of the at least one information bit as a first estimation bit value, and determining whether a log-likelihood ratio (LLR) indicating a probability ratio between bit values that are able to be estimated as the bit value of the first information bit is included in a first interval. In case that the LLR is included in the first interval, the method further comprises determining the bit value of the first information bit as a first estimation bit value or a second estimation bit value which is different from the first estimation bit value, by comparing a reliability value determined based on the LLR with at least one threshold.