Performance Analysis of Downlink NOMA System with Diversity Combining Schemes over k-µ Fading Channel

The employment of diversity combining methods by each user in a downlink multiuser NOMA system is presented. Each user specifically uses the maximum ratio combining (MRC), equal gain combining (EGC), and selection combining (SC) diversity approaches to boost the system's performance. The presented system's outage analysis for the
$L$
branch diversity combiner over the K-µ fading channel is provided. Additionally, a Laplace transform technique is used to develop an accurate closed-form equation of the probability density function (PDF) of the signal to noise ratio (SNR) at the output of an equal gain combiner for a K-µ fading channel. The given approach outperforms the traditional NOMA system, while NOMA with MRC diversity outperforms all other offered methods. The simulation results are used to confirm the theoretical findings.