Performance of NOMA-Enabled Integrated Sensing and Communication System with Imperfect CSI

Abstract

This work explores an integrated sensing and communication (ISAC) system where the base station operates in full-duplex mode, and simultaneously serves both uplink and downlink devices for communications, and also detects the presence of a target. Improving both communication and sensing performance, as well as spectral usage, motivates the adoption of non-orthogonal multiple access (NOMA) techniques in the ISAC system. Here, NOMA-ISAC integration is leveraged to maximize spectral efficiency, and with ISAC, we get greater data rates in future 6 G wireless technologies. This paper investigates and compares the performance of NOMA-ISAC and orthogonal multiple access (OMA)-ISAC frameworks under both perfect and imperfect channel state information, focusing on outage probability and spectral efficiency for communication, as well as the probability of detection and false alarm for sensing the targets. Both the theoretical and simulated results verify that ISAC-NOMA surpasses ISAC-OMA in outage probability and the probability of detection across both perfect and imperfect channel state information. © 2025 IEEE.