Patent ID: 6600445
Filing Date: 2003-07-29
Classification: H01Q

Abstract:
A method for calibrating a smart antenna array comprising N receiving and transmitting links, each link comprising an antenna unit and a radio frequency transceiver connected via a feeder cable, the method comprising:providing a calibration link comprising a coupling structure, a feeder cable and a pilot transceiver, wherein the coupling structure is coupled with N antenna units of the smart antenna array and the pilot transceiver is connected to a baseband processor of a base station by a digital bus; calibrating the coupling structure before the smart antenna array is put into operation, recording its receiving transmission coefficient and its transmitting transmission coefficient, respectively; calibrating receiving links: transmitting a defined voltage level calibrating signal at a set working carrier frequency by the pilot transceiver; receiving the signal at the same time by N receiving links of the smart antenna array to be calibrated; choosing a receiving link as a reference link, and equalizing the amplitude of the receiving transmission coefficient of each receiving link of the smart antenna array with the receiving transmission coefficient of the reference link, then calculating the phase difference &PHgr; between each receiving link and the reference link by using the recorded transmitting transmission coefficient of the coupling structure; and calibrating transmitting links: transmitting a defined voltage level calibrating signal at a set working carrier frequency by only one transmitting link, and setting all other transmitting links in a closing state at the same time; receiving signals coming from each transmitting link by the pilot transceiver, respectively; choosing a transmitting link as a reference link, and equalizing the amplitude of the transmitting transmission coefficient of each transmitting link of the smart antenna array with the transmitting transmission coefficient of the reference link, then calculating the phase difference &psgr; between each transmitting link and the reference link by using the recorded receiving transmission coefficient of the coupling structure.