Efficient Clock Offset Calibration Method for Uplink Sensing in Asynchronous ISAC System

Integrated sensing and communication attracts a lot of attentions due to its high spectrum efficiency. In this paper, a scenario of uplink sensing in perceptive mobile network is considered, where time offset (TO) and carrier frequency offset (CFO) are introduced into the signal due to the clock asynchronism between the transceiver. A clock offset calibration based method is proposed to solve the problem. The delay of line-of-sight (LOS) path is estimated first and the TO is calculated and compensated. Then, the received signal of LOS path is separated and correlated with the mixed signal to remove the CFO. Parameters can be estimated directly with the recovered signal. Numerical results verify the correctness of the method and demonstrate its high accuracy.