Certain aspects of the present disclosure provide a protocol for calibration of an access point in a wireless network. An access point transmits a training request message followed by a downlink sounding frame to a station to initiate the colibration procedure. The access point receives uplink sounding packets and channel state information (CSI) feedback from the station. The access point estimates the uplink channel from the uplink sounding packets and calibration coefficients from the received uplink sounding packets and the CSI feedback message. The calibration coefficients are applied to the channel estimated from the uplink sounding packets to correct the estimated channel; and a calibrated precoding matrix based on the corrected channel estimate is constructed in order to perform downlink transmissions.
