International Journal of Electrical and Computer Engineering (IJECE) Vol. 13, No. 2, April 2023, pp. 1639~1646 ISSN: 2088-8708, DOI: 10.11591/ijece.v13i2.pp1639-1646  1639 Journal homepage: http://ijece.iaescore.com New low-density-parity-check decoding approach based on the hard and soft decisions algorithms Hajar El Ouakili 1 , Hassan Touati 1 , Abdelilah Kadi 2 , Youness Mehdaoui 3 , Rachid El Alami 1 1 LISAC Laboratory, Faculty of Sciences, Sidi Mohamed Ben Abdellah University, Fez, Moroco 2 LSIA Laboratory, Faculty of Sciences and technology, Sidi Mohamed Ben Abdellah University, Fez, Moroco 3 Research team in Electronics, Instrumentation and Measurements, Université Sultan Moulay Slimane, Beni-Mellal, Morocco Article Info ABSTRACT Article history: Received Feb 27, 2022 Revised Sep 12, 2022 Accepted Oct 10, 2022 It is proved that hard decision algorithms are more appropriate than a soft decision for low-density parity-check (LDPC) decoding since they are less complex at the decoding level. On the other hand, it is notable that the soft decision algorithm outperforms the hard decision one in terms of the bit error rate (BER) gap. In order to minimize the BER and the gap between these two families of LDPC codes, a new LDPC decoding algorithm is suggested in this paper, which is based on both the normalized min-sum (NMS) and modified-weighted bit-flipping (MWBF). The proposed algorithm is named normalized min sum- modified weighted bit flipping (NMSMWBF). The MWBF is executed after the NMS algorithm. The simulations show that our algorithm outperforms the NMS in terms of BER at 10-8 over the additive white gaussian noise (AWGN) channel by 0.25 dB. Furthermore, the proposed NMSMWBF and the NMS are both at the same level of decoding difficulty. Keywords: Bit error rate Improved modified weighted bit flipping Low density parity check Modified weighted bit flipping Normalized min-sum This is an open access article under the CC BY-SA license. Corresponding Author: Hajar El Ouakili LISAC Laboratory, Faculty of Sciences, Sidi Mohamed Ben Abdellah University (USMBA) Fez, Moroco Email: hajar.elouakili@usmba.ac.ma 1. INTRODUCTION The low-density-parity-check (LDPC) codes are used in the next generation of optical communication organisms, as they are incorporated in the International Telecommunication Union Telecommunication (ITU-T) standards, like G.709 and G.975. LDPC codes are known by their highest coding gains and are suitable for any code-word length. They are generally iterative and based on information exchanged between the variable and check nodes. Indeed, many worldwide wireless application researchers have been drawn to the LDPC codes because of their importance in communication standards [1]. The min-sum (MS) algorithm is obtained by simplifying the check node processing of the sum-product (SP) algorithm, which also gives good results, and they belong to the soft decision algorithm which is based on the “extrinsic log likelihood ratio (LLRs) [2]–[6]. However, these algorithms require significant arithmetic operations with parallel implementation [7], [8] making them highly complex [9], [10]. Hard decision decoders, on the other hand, are similar to bit-flipping decoders [4], [11], [12] and they have a lower performance bit error rate (BER) than the min–sum (MS) and sum–product (SP) algorithms. However, they are less efficient computationally. Initially [4] proposed a weighted bit flipping (WBF) method as an upgrade to the bit flipping algorithm (BFA) in order to reduce error rates and boost a decoding stability. Following that, other WBF algorithm advancements were proposed, such as the modified weighted bit flipping (MWBF) algorithm [13], improved modified WBF (IMWBF) algorithm [14], improved reliability ratio WBF (RRWBF) algorithm [15], mixed modified weighted bit flipping (MMWBF) algorithm [16], improved low complex hybrid WBF (ILCHWBF)