Polar Code CRC Bit Spreading for Lower-Complexity Decoding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Polar coding in communication systems faces challenges with high decoding complexity and increased power consumption due to large list sizes required for satisfactory performance, particularly in machine type communication (mMTC) terminals, where large list sizes lead to increased storage space and longer decoding latency, and existing solutions like PC-Polar have high false alarm rates and inefficient code construction.
Innovation Solution
The method involves using polar encoding with error detection bits, where frozen bits are added to information bits, and CRC bits are distributed and transformed within the CRC generator matrix to improve decoding performance and error detection capability, reducing complexity and false alarm rates by optimizing the distribution and use of CRC bits during the decoding process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large list size is used in polar code decoding, then decoding performance is improved, but complexity and storage space increase
Solution Approach 1:
The patent segments the decoding process by introducing CRC check points at specific positions in the list decoding process. The decoding is divided into multiple stages with intermediate verification, allowing early elimination of erroneous paths without requiring a complete large-list decoding. This segmentation enables using a smaller list size while maintaining performance through staged verification.
Solution Approach 2:
The patent introduces CRC (cyclic redundancy check) bits as an intermediary mechanism between the encoder and decoder. These CRC bits serve as a mediator that enables verification of decoding paths without requiring the decoder to maintain a large list of all possible paths. The CRC acts as a filter that eliminates incorrect paths early in the decoding process.
2Reliability
If a large list size is used in polar code decoding, then decoding performance is improved, but power consumption increases
Solution Approach 1:
The patent segments the decoding process into multiple stages with intermediate CRC verification points. This segmentation allows the decoder to stop processing erroneous paths early rather than completing full decoding of all list elements, significantly reducing the computational energy required. The staged approach with verification points enables energy-efficient decoding by avoiding unnecessary computations on incorrect paths.
Solution Approach 2:
The patent applies partial action by performing CRC verification at intermediate stages rather than completing full list decoding. This allows the system to achieve satisfactory performance by processing only the necessary portion of the decoding task, eliminating the need to compute and store all L decoding paths when fewer are actually needed for achieving the target performance.
3Device complexity
If PC-Polar is used, then complexity is reduced, but false alarm rate increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing the CRC generator matrix and its properties before the actual decoding process. The system prepares the CRC verification mechanism in advance with optimized parameters and lookup tables, enabling efficient false alarm detection during decoding without adding runtime complexity. This preliminary preparation allows the system to maintain low operational complexity while achieving reliable false alarm reduction.
Data Source
Figure 1A~1B
Figure 2~3
Figure 4
AI summary
Embodiments of the present disclosure provide methods and apparatuses for data processing in a communication system. For example, the method comprises: generating, based on an intended performance, an error detection code to be used; distributing bits of the error detection code in information bits to be coded; and perform polar encoding on the information bits together with the error detection code distributed in the information bits. The embodiments of the present disclosure also provide a communication device capable of implementing the method.