NOMA Systems over Fluctuating Nakagami-m Fading Channels

Non-orthogonal multiple access (NOMA) is an emerging promising technology for beyond 5G and 6G networks. However, it is essential to investigate its performance over various fading channels. In this work, we shed light on the efficiency of downlink transmission of NOMA systems over the recently proposed Fluctuating Nakagami-m fading channels whose applications cover vehicle-to-vehicle (V2V) communications, and device-to-device (D2D) communications among others. Specifically, we consider an analytical study on the performance of a NOMA transmission in terms of the outage probability, diversity gain, coding gain, and ergodic capacity. The results show that the diversity gain of each user depends on the total number of multipath clusters ($m$) of the Fluctuating Nakagami-m fading channel, while the coding gain depends on several parameters including $m$, the fading severity parameter ($ms$), power allocation scheme, imperfection of the successive interference cancellation (SIC) scheme, and the QoS constraint. Two power allocation schemes have been investigated and compared. Representative simulations have validated the accuracy of the analytical derivations.