OTFS-Based Method for Interference Suppression in Integrated Communication and Sensing Systems

The orthogonal time frequency space (OTFS) modulation is a promising modulation scheme for next-generation integrated sensing and communication (ISAC) system. Nevertheless, there exists a problem of mutual interference between uplink communication signals and sensing echo signals, which leads to the degradation of both communication and sensing performance. For this reason, a successive interference cancellation (SIC) method based on the delay-Doppler (DD) domain to ensure the coexistence of communication and sensing is investigated in this paper. Firstly, the sensing echo signal is treated as interference to the communication signal, which is detected using a threshold-based channel estimation method and the Message Passing (MP) algorithm. The communication signal is then reconstructed and subtracted from the mixed signal. At last, the remaining signal is then subjected to parameter estimation with the Maximum Likelihood (ML) algorithm. Simulation results demonstrate that this method enables the ISAC system to function effectively in both communication and sensing. Additionally, compared to traditional interference suppression methods belong to TF domain, the performance of sensing parameter estimation is improved by approximately 2 dB.