Lowering the Error-Floor of CRC-Concatenated Polar Codes with Improved Partial Protection

• Published in: 2021 IEEE 94th Vehicular Technology Conference (VTC2021-Fall) pp. 1 - 6
• Main Authors: Ju, Hyosang, Park, Jisang, Chung, Min-Young, Kim, Sang-Hyo
• Format: Conference Proceeding
• Language: English
• Published: IEEE 01.09.2021
• Subjects: blind protection; Channel coding; cyclic redundancy check; Error probability; Generators; partial protection; Polar codes; Redundancy; Simulation; Vehicular and wireless technologies
• ISSN: 2577-2465
• DOI: 10.1109/VTC2021-Fall52928.2021.9625418

Unlike conventional cyclic redundancy check concatenated polar codes, selectively applying the CRC protection only to the crucial information bits (CIBs), namely 'partial protection', has an effect of lowering the error floor by reducing the number of low Hamming-weight codewords. In the conventional partial protection scheme, CRC is partially concatenated to the information bits whose corresponding row weight of the generator matrix is minimal. However, we observed that the performance even degrades when the protection range (i.e. related to the number of protected information bits) is low compared to the conventional CRC-concatenated polar codes. Therefore, in this paper, we propose a modified partial protection scheme based on a new CIB selection rule. We not only consider the row weight of the generator matrix, but also utilize the polarization weight which is a tool for assessing the quality of the split-channels of polar codes. Simulation results show that the proposed scheme can recover the weak point of the conventional partial protection scheme, thereby obtaining similar or better error-rate performance over all code parameters compared to the standard concatenation schemes.