Performance of Multiuser Uplink Underlay NOMA Networks With Channel Knowledge

The performance of a multiuser underlay uplink non-orthogonal multiple access network is investigated for the case when channel knowledge to selected users is present. A throughput optimal user subset selection scheme is developed for concurrent uplink transmission in any coherence interval while satisfying the interference temperature limit (ITL) of the primary receiver due to combined interference of all the transmitting users. Analytical expressions are derived for non-outage probability and throughput of the secondary network while accounting for successive interference cancellation (SIC) errors. A novel channel-aware ITL apportioning (CA-ITLA) scheme is proposed utilizing channel knowledge for intelligent apportioning of the ITL between all transmitting nodes. Performance of the proposed scheme is compared to benchmark schemes like random selection scheme (RSS) with CA-ITLA, static ITL apportioning (S-ITLA), RSS with S-ITLA, and orthogonal multiple access (OMA). It is shown that exploiting channel state information (CSI) enables CA-ITLA to accomplish significant throughput gains. It is shown that even better throughputs may be achieved by indirectly exploiting primary channel knowledge through a CSI-dependent ITL. Useful upper bounds on performance are also derived with static and CSI-dependent ITL. Monte Carlo simulations validate the presented analysis.