On Performance of Downlink NOMA with Equal Gain Combining over κ-μ Fading Channel for limiting value of κ

In this paper, an exact closed-form expression for probability density function (PDF) of signal-to-noise (SNR) at the output of equal gain combiner (EGC) is derived using Laplace transform approach for κ-μ fading channel. The derived expression is valid for κ→0, which is equivalent to Nakagami-m fading. Using on derived the PDF, the outage probability and the average sum-rate analysis of the non-orthogonal multiple access (NOMA) system with equal gain combining at each user are presented. This paper also investigates the impact of fading parameter μ, and diversity branches on the performance of the system under consideration. In addition, the performance of the proposed system is compared with that of the OMA system. Finally, the simulations are carried out to confirm the validity of the analytical expression.