Co-site Interference Suppression of Airborne Joint Communication and Sensing Platform Based on NYFR

The reconnaissance sensing equipment of the airborne anti-terrorism integrated sensing and communication (ISAC) platform is susceptible to interference from the co-platform communication signals, and interference reconstruction and suppression can overcome this problem. However, influenced by the channel change and algorithm accuracy, there is always a timing error between the co-platform interference reconstruction and the received signal. This causes a decrease in interference suppression performance. Motivated by this problem, the paper investigates the effect of timing errors on the performance of Nyquist folding receiver (NYFR) based co-site interference suppression. First, the airborne anti-terrorism ISAC platform is designed to include the command message transmitter and reconnaissance receiver. The reconnaissance receiver contains signal compression, co-site interference suppression, and signal-of-interest (SOI) reconstruction. Then, the effect of timing error on the performance of co-site interference suppression is theoretically analyzed, and the closed expression of the co-site interference suppression performance is derived. Theoretical analysis results show that the performance of NYFR-based co-site interference suppression is sensitive to timing errors. When the normalized timing error is 1%, and the power ratio of the co-site interference signal to noise (INR) is 40 dB, the interference suppression performance drops by 26 dB. Finally, the software radio platform is utilized to complete the experimental verification of NYFR-based co-site interference suppression.