On the Performance of Uplink ISAC Systems

TL;DR

This paper evaluates uplink ISAC system performance with NOMA, deriving key metrics and showing it outperforms traditional FDSAC in sensing rate when maintaining the same communication rate.

Contribution

It introduces novel analytical expressions for outage, ergodic rate, and sensing rate in uplink ISAC with NOMA, providing new insights into system performance.

Findings

ISAC achieves higher sensing rate than FDSAC at same communication rate

Derived expressions accurately predict outage probability and ergodic rate

Validated results through numerical simulations with excellent agreement

Abstract

This letter analyzes the performance of uplink integrated sensing and communications (ISAC) systems where communication users (CUs) and radar targets (RTs) share the same frequency band. A non-orthogonal multiple access (NOMA) protocol is adopted in the communication procedure of the ISAC system. Novel expressions are derived to characterize the outage probability, ergodic communication rate, and sensing rate. Besides, the diversity order and high signal-to-noise ratio (SNR) slope are unveiled to gain further insights. It is found that when achieving the same communication rate, the ISAC system enjoys a higher sensing rate than the conventional frequency-division sensing and communications (FDSAC) system where CUs and RTs share isolated bands. All the results are validated by numerical simulations and are in excellent agreement.