Impact of Phase Noise and Power Amplifier Nonlinearity on Realistic ISAC Networks from 3.5 GHz to 60 GHz

Abstract

Integrated Sensing and Communication (ISAC) systems impose more stringent requirements than communication only systems. They require absolute phase coherence across the OFDM frame for reliable Doppler and angle estimation. They further rely on sub-sample timing precision to achieve fine range resolution. Additionally, ISAC systems demand a high dynamic range to detect weak targets in the presence of strong reflections. In this study, we evaluate and characterise the impact of two of the most prominent hardware limitations, Local Oscillator (LO) Phase Noise and Power Amplifier (PA) nonlinearity on ISAC performance across five significant frequency bands (FR1 3.5 GHz New Radio (NR), outdoor 6 GHz WiFi 7, future 15 GHz cellular, FR2 26 GHz NR, and outdoor 60 GHz Wireless Gigabit (WiGig)). The simulation results quantify the extent impairment severity increases with operating frequency and illustrate the resulting trade-offs between communication reliability and sensing accuracy. Furthermore, the results identify, for each frequency band, the operational conditions under which both communication and sensing can successfully coexist and simultaneously satisfy their respective Service Level Agreements (SLAs).