Patent ID: 9094254
Filing Date: 2015-07-28
Classification: H04B,H04L

Abstract:
1. A method for calibrating an antenna array of a base station to remove distortion incurred by transmit paths in the base station, the antenna array including a plurality of sub-arrays coupled to the transmit paths for transmitting outbound traffic signals to a wireless network, the method comprising the steps of: capturing the outbound traffic signals for use as a feedback after the outbound traffic signals exit the transmit paths; capturing the outbound traffic signals for use as reference signals before the outbound traffic signals enter the transmit paths, each of the reference signals being one of the outbound traffic signals that is to be transmitted via one of the sub-arrays; performing an impairment estimation for each of the outbound traffic signals based on the feedback and the reference signals; determining, for each of the transmit paths, a set of weights of an all-pass filter, wherein the all-pass filter has a frequency response that approximates the impairment estimation in an occupied frequency region where signal power of the reference signals is above a threshold; inversing the set of weights to obtain equalizer taps for each of the transmit paths; and applying the equalizer taps to the outbound traffic signals before the outbound traffic signals enter the transmit paths to thereby remove the distortion incurred by the transmit paths.