A self-calibration algorithm for an asynchronous CDMA-based antenna array

A new iterative calibration algorithm for an asynchronous CDMA-based antenna array in the presence of unknown gain and phase errors is presented. The algorithm is applicable to a nonuniform array where the number of users could be greater than the number of antennas, and does not require a prior knowledge of the DOAs of the signals of any user. The method requires the code sequence of a reference user only. The proposed algorithm provides us with the joint estimates of the spatial signature and the channel impulse response of the used signal sources as well as the calibration of the sensor gains and phases, even under multiple access interference. The algorithm is near-far resistant and thus well suited for the multipath fading channel.