Capacity Analysis of Non-Orthogonal Multiple Access Systems over N-Nakagami Fading Channels for 5G and Beyond

Non-Orthogonal multiple access (NOMA) provides massive connectivity with high spectral efficiency. This makes it very appealing for fifth generation (5G) networks and beyond. In this paper, we derive the statistics in terms of probability density function (pdf) of the signal to noise ratio of every user assuming independent but not necessarily identical N-Nakagami-$m$ fading channels. Moreover, we derive analytical expressions for the capacity of each user. Numerical results are also provided to show the effects of different fading scenarios as well as different number of users on the capacity.