Design and Evaluation of Multi-layer NOMA on NR Physical Layer for 5G and Beyond

This paper investigates the integration of multi-layer non-orthogonal multiple access (N-NOMA) into a 5G New Radio (NR) compliant transceiver model, aiming to reveal the full potential of the NOMA technology in practical scenarios. We propose an N-NOMA-aided 5G NR physical layer (PHY) design, where a simplified multi-layer NOMA multiplexer with a one-shot multiplexing technique is developed to reduce the transmitter complexity and thus potential delay for processing the additional NOMA layers. Our design offers a new perspective for the NOMA technology to address various challenging use cases, such as massive machine type communication (mMTC) and enhanced mobile broadband (eMBB) under low signal-to-noise ratio (SNR) regimes. Then, in order to provide a comprehensive error performance evaluation of the proposed N-NOMA PHY design, we take into account various system configurations, e.g., different modulation and coding schemes (MCSs) with low-density parity-check (LDPC) code and different multi-input multi-output (MIMO) configurations. During the evaluation of the proposed design, we uncovered key factors missing from the existing bit error rate (BER) analytical models literature, e.g., the imperfect successive interference cancellation (SIC). The derived BER expressions capture the effect of the SIC errors, which is consistent in our analytical and simulation performance comparison. Through the simulation, we also comprehensively evaluate and discuss the link-level performance of the proposed PHY design.