Performance of Semi-Grant Free Uplink with Non-Orthogonal Multiple Access

In this paper we analyze the outage and throughput performance of a semi-grant free uplink based on non-orthogonal multiple access. We assume that the grant based user is selected in an opportunistic manner. We use underlay cognitive radio principles to manage interference to the grant based user. Expressions are derived for throughput of the non-grant based user. We show how power should be allocated to the opportunistically selected non-grant based uplink users to optimize their throughput performance while ensuring that performance of the grant-based user is maintained at the desired level. Computer simulations demonstrate accuracy of the derived expressions.