Phase Noise Mitigation in Bi-static OFDM-JCAS by Exploiting Static Clutter

Multi-static sensing via the existing communication infrastructure is a key enabler for joint communication and sensing (JCAS) in future wireless networks. Phase noise (PN), a critical hardware impairment, introduces range-Doppler sidelobes and necessitates precise compensation for reliable sensing. This work proposes a PN mitigation technique for bi-static sensing using orthogonal frequency division multiplexing (OFDM). Our approach leverages clutter to estimate and suppress PN effects from independent local oscillators at the transmitter (Tx) and receiver (Rx). By extracting clutter phase information in the range domain, the method effectively compensates the common phase error (CPE), enhancing target detectability and reducing sidelobe interference. Simulation results confirm the efficacy of the proposed method, achieving up to 30 dB suppression of PN-induced Doppler sidelobes and demonstrating its suitability for JCAS under realistic PN conditions.