A Fair Comparison Between OMA and NOMA For Cell-Free Massive MIMO Systems

Ruan Victor Pereira Failache, Aline A Ohashi, André Fernandes, Roberto Menezes Rodrigues, Andre Mendes Cavalcante, Joao Weyl Costa

DOI: 10.14209/sbrt.2021.1570724206

Evento: XXXIX Simpósio Brasileiro de Telecomunicações e Processamento de Sinais (SBrT2021)

Keywords: Cell-free massive MIMO Fair comparison NOMA Pilot contamination

Abstract

Non-orthogonal multiple access (NOMA) can improve the performance of cell-free massive MIMO systems by reducing the effects of pilot contamination. To assess NOMA performance most of the literature compares it with orthogonal multiple access (OMA). However, these works comparisons are unfair. From the authors' perspective, a fair comparison should consider the same number of users and pilots for NOMA and OMA. In this work, we evaluate these multiple access schemes under our envisioned fair terms. Our results show that NOMA provides gains of user spectral efficiency (SE) and aggregate sum-rate superior to OMA in normal and stressed scenarios.

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