Linear Regression for Phase Discontinuity Compensation in a Stepped-Carrier OFDM Radar

This article presents a novel real-time calibration technique for addressing the phase discontinuity between contiguous subbands in stepped-carrier orthogonal frequency division multiplexing (SC-OFDM) radar systems. The proposed technique leverages least-squares linear regression to estimate and compensate for the carrier stepping offsets (CSOs) of subbands based on multiband channel phase information obtained from the received signal. Unlike previously reported methods, the proposed technique does not require a reference target or additional radio-frequency (RF) chains and can operate in real-time. To evaluate its effectiveness, we implemented an SC-OFDM radar testbed with eight subbands in the 5 GHz frequency band, capable of estimating target ranges and radial velocities. Computer simulations were also conducted to evaluate performance statistics. The experimental results from the testbed in a real environment as well as the simulation results demonstrate the ability of the proposed technique to achieve clear range spectrums with suppressed spurious targets and improved range estimation performance of the targets.