Non-orthogonal multiple access (NOMA) stands out as an auspicious technique aimed at improving throughput, enabling maximum data rates (reaching 100+ MBPS), and reducing latency within the context of fifth-generation (5G) wireless communication systems, particularly in scenarios involving massive Internet of Things (IoT) connectivity. NOMA enables users to efficiently utilize shared frequency and time resources through power domain multiplexing. NOMA operates primarily based on two fundamental techniques. The first technique is superposition coding and the second method is successive interference cancelation(SIC). Within this context, the employed modulation schemes encompass binary phase shift keying (BPSK) and quadrature phase shift keying (QPSK). An evaluation and simulation of several key metrics in the NOMA system, such as bit error rate (BER), signal-to-interference noise ratio (SINR), channel capacity, and outage probability, are conducted. Specifically, our study focuses on the power domain downlink NOMA system, and we observe its performance under different channel conditions, including Rayleigh fading, Rician fading, and Additive White Gaussian Noise (AWGN) channel, involving two users. Furthermore, our investigation includes a comparative analysis of channel capacity and outage probability through simulation, contrasting the performance of MIMO NOMA with that of NOMA. The primary goal of NOMA is to promote spectrum sharing, a concept reminiscent of cognitive radio networks. NOMA has the potential to enhance channel capacity in the context of 6G communication systems.