This disclosure provides a device and method for synchronizing local oscillator (LO) chains. The method can include sampling first I-data and first Q-data to generate first sampled I-data and first sampled Q-data based on a sampling clock signal. The method can also include calibrating the sampling clock signal based on the first sampled I-data and the first sampled Q-data to generate a first calibrated sampling clock signal, the first calibrated sampling clock signal indicating an optimal sample position to sample the first I-data and the first Q-data. The method can also include synchronizing a phase of the first LO chain and a second LO chain based on the first calibrated sampling clock signal.