Polar Code CRC Segmentation for Lower-Latency Decoding
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Solution Overview
Problem
Polar codes face challenges with finite-length performance and high decoder latency due to serial decoding and energy expenditure on cyclic redundancy checks (CRCs), especially for short-to-medium block lengths.
Innovation Solution
The strategic placement of CRC bits within a polar code codeword, using a multi-dimensional interpretation of polar codes, and further encoding with non-polar codes to reduce decoding latency and improve performance, including distributed parity checks and selective insertion of error correction codes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If CRC bits are appended at the end of polar code codeword, then error detection capability is provided, but decoding latency increases due to serial decoding processing the entire codeword
Solution Approach 1:
The patent divides the polar code codeword into multiple segments and inserts CRC bits at specific positions within these segments rather than appending at the end. This segmentation allows the decoder to verify error detection earlier in the decoding process, reducing the effective latency while maintaining reliability.
Solution Approach 2:
The patent performs error detection checks at intermediate positions during the decoding process rather than waiting until the end. By placing CRC bits strategically within the codeword structure, the system can detect errors preliminarily and potentially terminate decoding early, reducing overall latency.
2Reliability
If CRC bits are inserted in multiple locations within codeword, then decoding performance is improved by maintaining correct path longer, but device complexity increases
Solution Approach 1:
The patent applies different CRC insertion strategies to different segments or regions of the polar code codeword based on their specific characteristics. By tailoring the CRC placement to local requirements of different code segments, the system optimizes decoding performance without uniformly increasing complexity across the entire system.
Solution Approach 2:
The patent views the polar code structure in a multi-dimensional framework, considering both the time/position dimension and the hierarchical code structure dimension. This dimensional perspective enables strategic CRC placement that maintains performance while managing complexity through structured design.
3Use of energy by moving object
If strategic placement of CRC bits is implemented, then energy expenditure is reduced, but manufacturing precision requirements increase for accurate CRC positioning
Solution Approach 1:
The patent pre-determines and stores the optimal positions for CRC bits based on the polar code structure and channel characteristics. This preliminary determination of CRC positions eliminates the need for complex real-time calculations during encoding and decoding, reducing energy expenditure while maintaining positioning accuracy through pre-computed tables or formulas.
Solution Approach 2:
The patent adjusts the parameters of CRC placement based on code length, rate, and channel conditions. By changing these parameters systematically rather than requiring precise manual positioning, the system reduces energy consumption while achieving accurate CRC placement through parameter-driven design.
Data Source
AI summary
Certain aspects of the present disclosure relate to techniques and apparatus for improving decoding latency and performance of Polar codes. An exemplary method generally includes generating a codeword by encoding information bits, using a multi-dimensional interpretation of a polar code of length N, determining, based on one or more criteria, a plurality of locations within the codeword to insert error correction codes generating the error correction codes based on corresponding portions of the information bits, inserting the error correction codes at the determined plurality of locations, and transmitting the codeword. Other aspects, embodiments, and features are also claimed and described.