Non-Orthogonal Multiple Access (NOMA) has been recommended as a feasible multiple access technique that satisfies the constraints of Fifth-generation (5G) communications systems. The upcoming Internet of Things (IoT) based life-enhancing application demands dense connection, maximal throughput, and reduction in latency. The research aims to analyze the Downlink performance of Power Domain NOMA (PD-NOMA) system in terms of Bit Error Rate (BER) under various channel conditions namely AWGN, Rayleigh, Rician and Nakagami-m with 5 User Equipments (UEs) in both Transmitting and Receiving end. The scenario is simulated using MATLAB Version 2021a. As PD-NOMA system allocates UE based on the optimal power of their Channel State Information, the significant enhancement in UE performance is accomplished. From the simulation results, it is found that both the near and far UEs experiences lesser BER under AWGN Channel. However, the same UEs under Rayleigh experiences higher BER with an increase of 40%. The far UEs result with higher BER when compared the near UE as the distance between BS and UE is increased.