Performance of User-Assisted Nonlinear Energy Harvesting NOMA Network with Alamouti/MRC

This paper focuses on evaluating the outage performance of a dual-hop single-phase non-orthogonal multiple-access (NOMA) system. The base station employs the Alamouti space-time block coding technique (Alamouti-STBC), enabling simultaneous communication with two mobile users, and the far user employs a maximal ratio combining (MRC) scheme. In this setup, the near user serves as a full-duplex (FD) (or half-duplex (HD)) energy harvesting (EH) relay, adopting decode-and-forward (DF) protocol for the far user. The study involves the development of a system model and the closed-form equations of exact and asymptotic outage probabilities (OP) over Nakagami-m fading channels with and without direct link considering a threshold-based nonlinear EH relaying model. We verify analytical results by Monte Carlo simulations and show that the presence of a direct link in the system enhances the performance of the far user considerably by mitigating the degradation caused by the self-interference in the near user.