Patent ID: 7596355

Claim:
A method of closed loop MIMO calibration in a wireless communication system, comprising: using mutual calibration in said wireless communication system by detecting that station calibration is obsolete and requires calibration; determining a range of automatic gain control which said station wants to calibrate and determining a list of transmission power for an Access Point (AP) in communication with said station; initiating by said station the calibration by sending said power list and N channel sounding preambles, where N is the number of transmit antennas at the station; receiving from said AP a channel matrix and L sets of channel sounding preambles with a different transmission power level for each set, where L is the number of entries in the power list; switching to an automatic gain control level of the station in response to the transmission power level received from said AP; and sending calibration data to said AP to calibrate a range of automatic gain control for the AP to transmit to the station.