US Patent 11451312 Mobile-assisted phase calibration method and system

Disclosed is a method of calibrating phase alignment of signals from multiple transmit antennas on multiple channels during OTA testing of a MIMO DUT, including generating a noisy test signal by adding noise to a signal pattern and transmitting the noisy test signal to the DUT on first and second channels OTA and sweeping a relative phase of the signal pattern, but not the added noise, in the first and second channels, while receiving from the DUT reports of a SNR for a received signal on at least one of the first channel and subsequently on the second channels. The method also includes analyzing variation in the SNR to determine phase alignment of the first and second channels, as received and processed by the DUT and using the determined phase alignment to perform OTA testing of the DUT. The method can also include receiving a RSRP and/or a RSSI.