Performance Comparison of DPS in NOMA for Different MIMO Antenna Configurations

The demand for an ever-increasing data rate and the growing number of users means that newer multiple-access technologies need to be developed. The paper considers how multiple input and multiple output (MIMO) systems can be implemented with non-orthogonal multiple access (NOMA) to determine the performance shift for dynamic power allocation schemes (DPS). Dynamic power allocation scheme is considered due to the wireless medium’s volatile nature. Monte-Carlo simulation has been used in this study and log-normal shadowing has been used as the path loss model. Rayleigh fading channel is considered for non-line of sight communication. The goal is to find the average spectral efficiency and outage probability for this setup for a range of antenna configurations from $2 \times 1$ to $4 \times 4$ and observe the variation across different antenna numbers. Both the near and the far users’ performance has been investigated. The findings show that although there is a definite pattern in MIMO for the far users, there is no such pattern for the near users. For a single antenna system, the near user performs better in average spectral efficiency up to a designated power level, after which MIMO takes over. For the far user, MIMO always outperforms the single antenna system. Also, several MIMO configurations are simulated to find the best-performing antenna system. The results conclude that as the transmitted power increases, the MIMO systems with the greater number of antennas perform better. However, this is not the case for the lower power level.