Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

IEEE/CIC International Conference on Communications in China (ICCC)

An LLR-Based Segmented Flipped SCL Decoding Algorithm for Polar Codes

Anqi Cao, Li Guo Zhang, Jian Qiao, Yejun He

Published Aug 1, 2019• 9 citations
Publisher

Abstract

Polar codes have attracted significant attention in the field of communication, for the capacity-achieving under binary-input discrete memoryless channels (BDMCs). On the basis of successive cancellation (SC) decoding algorithm, many excellent methods have been developed to improve the decoding performance on short and medium codes. In this paper, an LLR-based segmented flipped successive cancellation list (LLR-based SF-SCL) decoding algorithm is proposed, where the information bits are divided into segments for early bit-flipping and termination. In order to make the unreliable bits evenly distributed in each sub-block, an LLR-based segmentation scheme is applied. Simulation results show that the proposed segmented flipped algorithm is superior to CRC-aided successive cancellation list (CA-SCL) algorithm in the block error rate (BLER) performance, and LLR-based segmentation scheme has better performance compared to uniform segmentation scheme.

DOI
10.1109/iccchina.2019.8855853

Related papers

An Improved Segmented Flipped Successive Cancellation List Decoder for Polar Codes

Yunlong Peng, Xingcheng Liu, Jingyun Bao

Several studies have documented that segmentation can improve the performance of polar codes based on CRC-aided successive cancellation list (CA-SCL) decoding algorithm. In this paper, we propose a new segmented CA-SCL decoder, referred to as improved segmented flipped successive cancellation list (ISF-SCL) decoder, with a reasonable segmentation strategy and a number of extra flipping attempts. Different from the existing methods, in which the uniform segmentation or LLR based segmentation scheme was adopted, a novel segmentation strategy that we firstly analyzed and proposed is based on the distribution of the correct path elimination. Hence, the segment effectiveness is promoted. In addition, to further improve the error correcting performance, a multi-path flipped strategy is proposed to restore the correct path eliminated from the list. Simulation results show that the performance of the ISF-SCL decoding algorithm is superior to the existing segmented CA-SCL decoding algorithms in the low signal-to-noise ratio regime, while the average computational complexity does not increase significantly.

IEEE International Conference on Computer and Communications (ICCC)•Dec 11, 2020•4 citations

An Error Segment Bit-Flip Algorithm for Successive Cancellation List Decoding of Polar Codes

Jing Zhang, Hongbing Qiu, Ling Zhan +1 more

Polar codes have garnered significant attention since they were proposed due to their capacity-achieving properties and their low-complexity decoding process, and they were selected as the coding scheme for the control channel in 5G mobile communication technology. A successive cancellation list (SCL) decoder, aided by a cyclic redundancy check (CRC), performs the competitive error correcting performance for polar codes compared to other sophisticated codes. The SCL-Flip decoding algorithm is proposed to enhance the error correction performance of the SCL. However, the SCL-Flip is hampered by a high decoding complexity due to the necessary selection and sorting process of path metrics (PMs). Additionally, it requires a large number of iterations to achieve a good error correction performance. In this paper, we propose the error segment bit-flip (ES-SCL-Flip) decoding algorithm, a simplified bit-flip approach for the SCL decoder based on analyzing the distributions of the first error bit. Firstly, we construct an index set with a high probability of the first erroneous bit. Second, a bit-flip criterion is introduced to prevent the costly operation of the PM selection and sorting without compromising the error correction performance. Finally, a search strategy is employed that utilizes segmented error indication to target and rectify the initial error segment sequentially. The simulation results demonstrate that the ES-SCL-Flip decoder provides an improved error correction performance with only a minimal increase in decoding complexity compared to the conventional CRC-aided SCL decoder. This algorithm attains a commendable equilibrium between the error correction performance and decoding complexity.

Mathematics•Jul 2, 2024•1 citation

An Improved Multiple Bit-Flipping Successive Cancellation Decoding Algorithm for Polar Codes

Sha Sha, Li Guo Zhang, Yejun He

Although original successive cancellation flip (SCF) decoding of the polar codes can identify the first error position and flip the error, decoding still fails when other errors occur after the corrected error bit. Therefore, the improvement of the block error rate (BLER) performance is limited. In this paper, we present an improved algorithm that can correct multiple error bits, named as improved multiple bit-flipping successive cancellation decoding algorithm. First, multiple sets are constructed by calculating the log likelihood ratio (LLR) of each information bit. Then, a bit is selected and corrected from the first set when original decoding fails; two bits are selected and flipped from the second set when all bits in the first set cannot be successfully decoded; when all bits combinations in the second set are flipped but the output vector still does not match the input vector, three bits are selected and corrected from the third set. Simulation results show that the BLER performance of the improved algorithm is better than that of the successive cancellation list decoding (SCL) decoding algorithm with a list size of L = 8 for N = 256. When N = 1024 and SNR = 3 dB, the BLER performance of improved algorithm is slightly better than that of SCL decoding algorithm with a list size of L = 4.

International Conference on Wireless Communications and Signal Processing (WCSP)•Oct 21, 2020•1 citation

Improved Successive Cancelation List Decoding for Polar Codes Using Vulnerable Frozen Bits LLRs

Qasim Jan, Zakir Ali, Hafeez Anwar +2 more

Successive cancellation list (SCL) decoding for polar codes has the ability to achieve Shannon capacity over the binary discrete memoryless channel. However, a large list size is required to achieve the Shannon capacity limit. Consequently, this paper proposes a novel iterative method for the CA-SCL decoder based on frozen bits to improve the error-correction performance of CA-SCL decoding for polar codes with smaller list sizes. The proposed technique determines the vulnerable channel log-likelihood ratios (LLRs) for frozen bits that degrade the CA-SCL decoding error correction performance and corrects them for the next CA-SCL decoding attempt. We analyze the behavior of wrongly estimated LLRs of frozen bits during CA-SCL decoding and design an attenuation factor set using a greedy algorithm. The proposed technique employs iterative CA-SCL decoding and revises the wrongly estimated frozen bit LLRs using the attenuation factor set during the decoding process. The simulation results show that the proposed technique achieves a block error rate (BLER) performance gain of up to 0.25 compared with the CA-SCL decoder, with a minor increase in computational complexity. Moreover, the attenuation factor set can be adjusted arbitrarily to balance performance and complexity.

IEEE Internet of Things Journal•May 7, 2025•0 citations

Successive Cancellation List Flip Decoding for eBCH-polar Codes

Wei-Cheng Wang, Meng-Ru Wu, Shan Lu +2 more

The eBCH-polar codes is a powerful way to construct polar codes. With high minimum Hamming distance, it outperforms ordinary Polar codes under successive cancellation list (SCL) decoder. However, the absence of cyclic redundancy check (CRC) bits in eBCH-polar codes makes it challenging to adopt SCL-flip (SCLF) decoding scheme. In this research, we propose a flip scheme activated by a Normalized Path Metric (PM) range and a mismatch criterion, which respectively leverage the properties of SCL decoding and dynamic frozen bits of eBCH-polar codes. This work also improves the selection the flipping bits by modifying metric to account for the structure of dynamic frozen bits and reduce the search space. Based on these modifications, we proposed SCLF-1 and SCLF-2 decoding algorithms for eBCH-polar codes. Simulation results show that both of the proposed decoding schemes achieve superior performance compared to other contemporary decoding algorithms for CRC aided polar (CA-polar) codes, demonstrating enhanced error rates performance within the same decoding attempt.

IEEE Vehicular Technology Conference•Oct 19, 2025•0 citations

An Improved Bit-Flipping Based Decoding Algorithm for Polar Codes

Xiao Hu, Shufeng Li, Mingyu Cai

In this paper, we propose three improved bit flipping algorithms in successive cancellation (SC) decoding and successive cancellation list (SCL) decoding. Weighted single-bit flipping successive cancellation (WSFSC) decoding first performs SC decoding on the output sequence, T bits with the smallest product of channel capacity and absolute value of LLR are regarded as unreliable bits. In multi-bit flipping successive cancellation (MFSC) algorithm, the unreliable bits are respectively corrected according to the single-bit flipping and multi-bit flipping rules. In single flipping successive cancellation list (SFSCL) algorithm, by subtracting a large penalty value from the path metric (PM) value of the unreliable bit, the decoding path corresponding to this bit is more likely to be pruned during path screening, so as to realize bit flipping indirectly. Simulation results show that the proposed WSFSC and MFSC algorithm has a gain of 0.3dB compared with the traditional SC algorithm, SFSCL algorithm has a gain of 0.3dB compared with the traditional SCL algorithm.

IEEE International Conference on Control Science and Systems Engineering (ICCSSE)•Jul 30, 2021•2 citations
Polar codes have attracted significant attention in the field of communication, for the capacity-achieving under binary-input discrete memoryless channels (BDMCs). On the basis of successive cancellation (SC) decoding algorithm, many excellent methods have been developed to improve the decoding performance on short and medium codes. In this paper, an LLR-based segmented flipped successive cancellation list (LLR-based SF-SCL) decoding algorithm is proposed, where the information bits are divided into segments for early bit-flipping and termination. In order to make the unreliable bits evenly distributed in each sub-block, an LLR-based segmentation scheme is applied. Simulation results show that the proposed segmented flipped algorithm is superior to CRC-aided successive cancellation list (CA-SCL) algorithm in the block error rate (BLER) performance, and LLR-based segmentation scheme has better performance compared to uniform segmentation scheme.
Several studies have documented that segmentation can improve the performance of polar codes based on CRC-aided successive cancellation list (CA-SCL) decoding algorithm. In this paper, we propose a new segmented CA-SCL decoder, referred to as improved segmented flipped successive cancellation list (ISF-SCL) decoder, with a reasonable segmentation strategy and a number of extra flipping attempts. Different from the existing methods, in which the uniform segmentation or LLR based segmentation scheme was adopted, a novel segmentation strategy that we firstly analyzed and proposed is based on the distribution of the correct path elimination. Hence, the segment effectiveness is promoted. In addition, to further improve the error correcting performance, a multi-path flipped strategy is proposed to restore the correct path eliminated from the list. Simulation results show that the performance of the ISF-SCL decoding algorithm is superior to the existing segmented CA-SCL decoding algorithms in the low signal-to-noise ratio regime, while the average computational complexity does not increase significantly.
Polar codes have garnered significant attention since they were proposed due to their capacity-achieving properties and their low-complexity decoding process, and they were selected as the coding scheme for the control channel in 5G mobile communication technology. A successive cancellation list (SCL) decoder, aided by a cyclic redundancy check (CRC), performs the competitive error correcting performance for polar codes compared to other sophisticated codes. The SCL-Flip decoding algorithm is proposed to enhance the error correction performance of the SCL. However, the SCL-Flip is hampered by a high decoding complexity due to the necessary selection and sorting process of path metrics (PMs). Additionally, it requires a large number of iterations to achieve a good error correction performance. In this paper, we propose the error segment bit-flip (ES-SCL-Flip) decoding algorithm, a simplified bit-flip approach for the SCL decoder based on analyzing the distributions of the first error bit. Firstly, we construct an index set with a high probability of the first erroneous bit. Second, a bit-flip criterion is introduced to prevent the costly operation of the PM selection and sorting without compromising the error correction performance. Finally, a search strategy is employed that utilizes segmented error indication to target and rectify the initial error segment sequentially. The simulation results demonstrate that the ES-SCL-Flip decoder provides an improved error correction performance with only a minimal increase in decoding complexity compared to the conventional CRC-aided SCL decoder. This algorithm attains a commendable equilibrium between the error correction performance and decoding complexity.
Although original successive cancellation flip (SCF) decoding of the polar codes can identify the first error position and flip the error, decoding still fails when other errors occur after the corrected error bit. Therefore, the improvement of the block error rate (BLER) performance is limited. In this paper, we present an improved algorithm that can correct multiple error bits, named as improved multiple bit-flipping successive cancellation decoding algorithm. First, multiple sets are constructed by calculating the log likelihood ratio (LLR) of each information bit. Then, a bit is selected and corrected from the first set when original decoding fails; two bits are selected and flipped from the second set when all bits in the first set cannot be successfully decoded; when all bits combinations in the second set are flipped but the output vector still does not match the input vector, three bits are selected and corrected from the third set. Simulation results show that the BLER performance of the improved algorithm is better than that of the successive cancellation list decoding (SCL) decoding algorithm with a list size of L = 8 for N = 256. When N = 1024 and SNR = 3 dB, the BLER performance of improved algorithm is slightly better than that of SCL decoding algorithm with a list size of L = 4.
Successive cancellation list (SCL) decoding for polar codes has the ability to achieve Shannon capacity over the binary discrete memoryless channel. However, a large list size is required to achieve the Shannon capacity limit. Consequently, this paper proposes a novel iterative method for the CA-SCL decoder based on frozen bits to improve the error-correction performance of CA-SCL decoding for polar codes with smaller list sizes. The proposed technique determines the vulnerable channel log-likelihood ratios (LLRs) for frozen bits that degrade the CA-SCL decoding error correction performance and corrects them for the next CA-SCL decoding attempt. We analyze the behavior of wrongly estimated LLRs of frozen bits during CA-SCL decoding and design an attenuation factor set using a greedy algorithm. The proposed technique employs iterative CA-SCL decoding and revises the wrongly estimated frozen bit LLRs using the attenuation factor set during the decoding process. The simulation results show that the proposed technique achieves a block error rate (BLER) performance gain of up to 0.25 compared with the CA-SCL decoder, with a minor increase in computational complexity. Moreover, the attenuation factor set can be adjusted arbitrarily to balance performance and complexity.
The eBCH-polar codes is a powerful way to construct polar codes. With high minimum Hamming distance, it outperforms ordinary Polar codes under successive cancellation list (SCL) decoder. However, the absence of cyclic redundancy check (CRC) bits in eBCH-polar codes makes it challenging to adopt SCL-flip (SCLF) decoding scheme. In this research, we propose a flip scheme activated by a Normalized Path Metric (PM) range and a mismatch criterion, which respectively leverage the properties of SCL decoding and dynamic frozen bits of eBCH-polar codes. This work also improves the selection the flipping bits by modifying metric to account for the structure of dynamic frozen bits and reduce the search space. Based on these modifications, we proposed SCLF-1 and SCLF-2 decoding algorithms for eBCH-polar codes. Simulation results show that both of the proposed decoding schemes achieve superior performance compared to other contemporary decoding algorithms for CRC aided polar (CA-polar) codes, demonstrating enhanced error rates performance within the same decoding attempt.
In this paper, we propose three improved bit flipping algorithms in successive cancellation (SC) decoding and successive cancellation list (SCL) decoding. Weighted single-bit flipping successive cancellation (WSFSC) decoding first performs SC decoding on the output sequence, T bits with the smallest product of channel capacity and absolute value of LLR are regarded as unreliable bits. In multi-bit flipping successive cancellation (MFSC) algorithm, the unreliable bits are respectively corrected according to the single-bit flipping and multi-bit flipping rules. In single flipping successive cancellation list (SFSCL) algorithm, by subtracting a large penalty value from the path metric (PM) value of the unreliable bit, the decoding path corresponding to this bit is more likely to be pruned during path screening, so as to realize bit flipping indirectly. Simulation results show that the proposed WSFSC and MFSC algorithm has a gain of 0.3dB compared with the traditional SC algorithm, SFSCL algorithm has a gain of 0.3dB compared with the traditional SCL algorithm.