On the Performance of NOMA Networks Supported by RIS in a Cooperative Environment

This paper consider a reconfigurable intelligent surface (RIS)-assisted non-orthogonal multiple access (NOMA) system in the cooperative scenarios. The RIS is deployed to assist far user under severe channel fading conditions. Near user act as cooperative relays in network, providing more options for the establishment of far user communication links. We derived the exact outage probabilities of the network under the assumption of Nakagami-m fading in the channel. Furthermore, the asymptotic expression of outage probability is derived and the factors affecting the diversity order of the system are found.