Performance of NOMA-Based Spectrally-Efficient Uplink Underlay Multiuser Networks With Imperfect SIC

This paper analyzes the performance of a spectrally-efficient non-orthogonal multiple access (NOMA) based signalling scheme in which two selected users are scheduled for uplink transmissions in an underlay multiuser network, taking successive interference cancellation (SIC) errors into account. The transmit powers of users are adjusted to maximize throughput while jointly satisfying the interference temperature limit (ITL) imposed by the primary receiver. The ITL is first assumed to be a statistically fixed quantity. Analytical expressions are derived for outage and throughput. Performance is then analyzed for the case of channel state information (CSI) dependent ITL. It is demonstrated that by indirectly exploiting primary channel knowledge, CSI dependent ITL ensures large throughput gains. Our results show the superiority of the proposed scheme using NOMA compared to conventional underlay orthogonal multiple access (OMA). Computer simulations confirm accuracy of the derived expressions.