Walsh–Hadamard Transform Based Non-Orthogonal Multiple Access (NOMA) and Interference Rejection Combining in Next-Generation HetNets

M. Rehan Usman, M. Arslan Usman, Soo Young Shin, Gandeva Bayu Satrya, Rizwan A. Naqvi, Maria G. Martini and Christos Politis
Additional contact information
M. Rehan Usman: Department of Electrical Engineering, The Superior College (University Campus), 17 Km Raiwind Road, Lahore 54000, Pakistan
M. Arslan Usman: Department of Research, Business and Innovation, Kingston University London, Kingston upon Thames KT1 2EE, UK
Soo Young Shin: Department of IT Convergence Engineering, Kumoh National Institute of Technology (KIT), Gumi 39177, Korea
Gandeva Bayu Satrya: School of Applied Sciences, Telkom University, Telekomunikasi St. No. 1, Bandung 40257, Indonesia
Rizwan A. Naqvi: Department of Unmanned Vehicle Engineering, Sejong University, 209, Neungdong-ro, Gwangjin-gu, Seoul 05006, Korea
Maria G. Martini: Faculty of Science, Engineering and Computing, Kingston University London, Kingston upon Thames KT1 2EE, UK
Christos Politis: Faculty of Science, Engineering and Computing, Kingston University London, Kingston upon Thames KT1 2EE, UK

Mathematics, 2021, vol. 9, issue 4, 1-26

Abstract: In heterogeneous networks (HetNets), non-orthogonal multiple access (NOMA) has recently been proposed for hybrid-access small-cells, promising a manifold network capacity compared to OMA. One of the major issues with the installation of a hybrid-access mechanism in small-cells is the cross-tier interference (intercell interference (ICI)) caused by the macrocell users (MUs) that are unable to establish a connection to the small-cell base station (SBS). In this paper, a joint strategy is proposed for hybrid-access small-cells using the Walsh–Hadamard transform (WHT) with NOMA and interference rejection combining (IRC) to achieve high performance gains and mitigate intercell interference (ICI), respectively. WHT is applied mathematically as an orthogonal variable spreading factor (OVSF) to achieve diversity in communication systems. When applied jointly with NOMA, it ensures better performance gains than the conventional NOMA. It reduces the bit error rate (BER) and enhances subsequent throughput performance of the system. IRC is used at the receiver side for managing the cross-tier interference caused by MUs that are unable to connect to the small-cell base station (SBS) for hybrid-access. The work considers both ideal and nonideal successive interference cancellation (SIC) conditions for NOMA. Mathematical modeling is provided for the proposed joint strategy for HetNets and the results validate it in terms of BER and subsequent user throughput performance, compared to the conventional NOMA approach.

Keywords: heterogeneous networks (HetNets); non-orthogonal multiple access (NOMA); successive interference cancellation (SIC); interference rejection combining (IRC); Walsh-Hadamard transform (search for similar items in EconPapers)
JEL-codes: C (search for similar items in EconPapers)
Date: 2021
References: View complete reference list from CitEc
Citations: View citations in EconPapers (1)

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