Patent ID: 6690953
Filing Date: 2004-02-10
Classification: H01Q,H04B

Abstract:
A method for calibration of an adaptive antenna array connected via possible filters to receivers and transmitters of a radio base station, comprising the steps ofperforming a first step of receive branch calibration by tuning one of the transmitters to a receive frequency and feeding the transmit signal to all receiver branches via respective possible filters in the signal path; comparing received signals on a channel basis to obtain differences between receive branches at a receive frequency; performing a second step of pre-transmit calibration by tuning one transmitter to a transmit frequency and injecting the transmit signal to all receiver branches tuned to the transmit frequency while excluding respective possible filters in the signal path; performing a third step of transmit branch calibration by connecting each transmit branch to one of the receive branches via respective possible filters in the signal path; subtracting pre-transmit calibration from the transmit calibration result to obtain a residue value for amplitude and phase to be compared on a channel base to obtain differences between transmit branches at a transmit frequency; compiling correlation factors between signals from all antenna branches in a matrix for implementation in a control unit for obtaining an ability to correct errors in phase and amplitude in the adaptive antenna array.