[This article belongs to Volume - 56, Issue - 01, 2024]
Gongcheng Kexue Yu Jishu/Advanced Engineering Science
Journal ID : AES-09-05-2024-45

Anil Kumar T, N Sathisha

Abstract :

This study explores the integration of Non-Orthogonal Multiple Access (NOMA) and Multiple Input Multiple Output (MIMO) technologies to enhance communication systems' performance metrics in both downlink (DL) and uplink (UL) scenarios. Specifically, the research focuses on improving bit error rates, spectrum efficiency, and average capacity rates, while also examining the reduction in outage probability. By leveraging the inherent advantages of NOMA in increasing user capacity and spectrum efficiency, and combining these with the spatial multiplexing and diversity gains provided by MIMO technology, this paper proposes a novel framework that optimally utilizes the spectral resources and enhances the reliability of wireless networks. Extensive simulations and analytical evaluations demonstrate significant improvements in system throughput and robustness, providing a comprehensive solution that could be pivotal for future wireless communication systems, particularly in the context of 5G and beyond. The results highlight not only the theoretical advancements but also practical considerations for implementation, offering valuable insights for both academia and industry in the field of wireless communications. Methods: The transmission subcarriers for each user are allocated according to their optimal power in NOMA-MIMO. Superposition coding is used at the transmitter and successive interference cancellation at the receiver. It includes uplinks, downlinks, and MIMO extensions for NOMA. With QPSK modulation, four users with varying power coefficients, a SNR and transmit power, and two contrasting bandwidths 90 and 210 MHz, the model uses selective frequency Rayleigh fading. Findings: The DL results found that the BER and SE against transmitted power showed the MIMO-NOMA enhanced the BER performance for the best user U4 from 10−1.7 to 10−5.2 at 90 MHz bandwidth , and from 10−1.5 to 10−5 at 210 MHz for transmitting power of 40 dBm. In contrast, the SE performance for the best user U4 is enhanced from 24 × 10−3 to 25 × 10−3 bits/second/Hz at 90 MHz BW and from 19.8 × 10−3 to 20 × 10−3 bps/Hz at 210 MHz BW. Although the outcomes for the UL were obtained in terms of average capacity rate and OP versus SNR at 90, and 210 MHz BW, the MIMO-NOMA result showed that the average capacity rate for the best user U4 performance improves by 12 bps/Hz for 1 dB SNR and the OP is reduced by 15 × 10−3 for 90 MHz BW and by 12 × 10−3 for 210 MHz BW at an SNR of 0.17 dB. Novelty: Two different bandwidths were investigated for the system over a Rayleigh fading channel; and a new power domain scheme was proposed for NOMA-MIMO to increase data rate, throughput, and capacity.