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JCM 2024 Vol.19(11): 546-557
DOI: 10.12720/jcm.19.11.546-557

Fifth-Generation Low-Density Parity-Check Codes in the Turbo Equalization of Faster-than-Nyquist Signaling

Asma A. Alqudah1*, Khaled F. Hayajneh2, Hasan A. Aldiabat1, and Hazim M. Shakhatreh1
11Department of Telecommunications Engineering, Hijjawi Faculty for Engineering Technology, Yarmouk University, Irbid 21163, Jordan
2Computer Engineering Department, College of Engineering and Technology, American University of the Middle East, Egaila 54200, Kuwait
Email: asma.qudah@yu.edu.jo (A. A. A.); Khaled.hayajneh@aum.edu.kw (K. F. H.); hasan.aldiabat@yu.edu.jo (H. A. A.); hazim.s@yu.edu.jo (H. M. S.)
*Corresponding author

Manuscript received August 2, 2024; revised September 4, 2024, accepted September 13, 2024; published November 25, 2024.

Abstract—The so-called faster-than-Nyquist signaling scheme has recently emerged as a highly promising technique, garnering significant attention for its remarkable ability to efficiently utilize bandwidth by packing more data than conventional systems. In parallel, employing Low-Density Parity-Check (LDPC) codes, a celebrated capacity-approaching forward-error correction (FEC) technique has revolutionized communications. This paper investigates the performance of the 5G new radio layered LDPC codes when employed as the constituent outer block for decoding within the context of the iterative turbo equalization method. The focus lies on effectively mitigating the severe interference introduced by the faster-than-Nyquist (FTN) scheme. The LDPC coding is implemented using parity check matrices derived from the 5G communications standard. To evaluate the system's performance, simulations are conducted using varying sizes of base matrices. Simulations demonstrate the impact of employing different base matrix sizes and quantify the performance gain achieved by employing varying numbers of iterations for the decoding process. The obtained results showcase the superiority of the proposed scheme, as measured by the signal-to-noise ratio (SNR) gain (in dB) when compared to a Nyquist signaling system possessing the same data-carrying capabilities. These findings offer compelling evidence of the potential of our proposed approach in terms of enhancing spectral efficiency and delivering improved performance in the presence of severe interference. The approach utilizes the regularity in the structure of the 5G NR LDPC base matrices and provides efficient layered decoding scheme that contributes to the fast convergence of the decoding process. The proposed scheme of the 5G NR LDPC decoder in the context of severe FTN turbo equalization proves superior to the uncoded QPSK transmission over additive white Gaussian noise (AWGN) channel, with a gain of ~5 dB at the same data rate and the same transmission power. 
 

Keywords—5G low-density parity check, faster-than-Nyquist, belief propagation, iterative decoding, log-likelihood ratio, intersymbol interference, turbo equalization


Cite: Asma A. Alqudah, Khaled F. Hayajneh, Hasan A. Aldiabat, and Hazim M. Shakhatreh, “Fifth-Generation Low-Density Parity-Check Codes in the Turbo Equalization of Faster-than-Nyquist Signaling," Journal of Communications, vol. 19, no. 11, pp. 546-557, 2024.

 

Copyright © 2024 by the authors. This is an open access article distributed under the Creative Commons Attribution License (CC BY-NC-ND 4.0), which permits use, distribution and reproduction in any medium, provided that the article is properly cited, the use is non-commercial and no modifications or adaptations are made.