Polar Channel Encoding With CRC Bit Positioning for Unequal Protection
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Solution Overview
Problem
Polar codes in wireless communication systems face efficiency issues when used without CRC in scenarios with low information bits, leading to decreased transmission efficiency compared to Tail-Biting Convolutional Codes, and simply removing CRC in traditional LTE systems renders error check and target receiver identification impossible.
Innovation Solution
A method that adjusts the position of bits in a third bit block based on the number of bits in the first and second bit blocks, using CRC bits to generate the second bit block, allowing for unequal error protection and improved decoding accuracy by mapping bits of different importance to sub-channels with varying reliability, while maintaining the functions of traditional CRC through proper positional design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polar code adopts CRC bit for error checking, then reliability is improved, but transmission efficiency deteriorates due to decreased throughput when number of information bits is low
Solution Approach 1:
The patent segments the bit block into information bits and CRC bits with distinct positional arrangements. The CRC bits are positioned at specific locations (e.g., first bit position) while information bits occupy other positions, allowing the decoder to efficiently identify and process CRC bits for error checking without disrupting the overall decoding flow, thus maintaining reliability while improving efficiency.
Solution Approach 2:
The patent performs preliminary positioning of CRC bits within the bit block before transmission. By pre-determining the positions of CRC bits (e.g., placing them at the beginning or at specific intervals), the receiver can quickly locate and extract CRC bits for error checking without requiring complex search procedures, thereby maintaining reliability while reducing processing overhead and improving transmission efficiency.
2Productivity
If polar code does not adopt CRC, then transmission efficiency is improved, but reliability deteriorates as error check and target receiver identification functions become impossible
Solution Approach 1:
The patent segments the bit block into distinct information bits and CRC bits with clear positional separation. This segmentation allows the system to maintain CRC functionality for error checking and receiver identification while using polar code for efficient encoding, thus preserving reliability without sacrificing transmission efficiency.
Solution Approach 2:
The patent applies different functions to different parts of the bit block: CRC bits at specific positions provide error checking and identification, while information bits at other positions carry the actual data. This local differentiation allows each part to optimize its function, maintaining reliability through CRC while achieving high transmission efficiency through polar code encoding of the information bits.
3Device complexity
If bits are mapped to sub-channels without positional adjustment, then device complexity is reduced, but manufacturing precision deteriorates as equal error protection cannot be provided for bits of different importance
Solution Approach 1:
The patent applies different error protection strategies to different bits based on their importance and position. CRC bits at specific positions receive enhanced protection through their strategic placement, while information bits are protected through polar code encoding. This local differentiation provides unequal error protection that matches the importance of different bits, improving overall transmission reliability without requiring complex adaptive mapping mechanisms.
Solution Approach 2:
The patent performs preliminary positioning of bits according to their importance before channel mapping. By pre-arranging CRC bits at protected positions and information bits at other positions, the system ensures that critical bits receive appropriate error protection without requiring complex real-time adjustments during channel mapping, thus maintaining simplicity while achieving precise error protection.
4Productivity
If CRC bits are simply removed from polar code, then transmission efficiency is improved, but adaptability deteriorates as the system cannot maintain traditional CRC functions for various error scenarios
Solution Approach 1:
The patent segments the bit block to preserve CRC bits at specific positions while allowing polar code encoding of information bits. This segmentation maintains the adaptability of traditional CRC functions for error checking and receiver identification while achieving the transmission efficiency benefits of polar code, thus resolving the contradiction between efficiency and adaptability.
Solution Approach 2:
The patent makes the bit block structure universal by incorporating both CRC bits and information bits in a unified polar code framework. The CRC bits maintain their traditional error checking and identification functions across various error scenarios, while the information bits benefit from polar code encoding, achieving both adaptability and efficiency in a single system.
Data Source
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AI summary
The disclosure discloses a method and device in UE and a base station for channel coding. A first node first determines a first bit block and then transmits a first radio signal, wherein bits of the first bit block are used to generate bits of a second bit block, a third bit block comprises bits of the second bit block and the first bit block, and the third bit block is used to generate the first radio signal. The first bit block, the second bit block and the third bit block comprise P1, P2 and P3 bits, respectively.