The present invention provides a method of estimating a channel quality of a wireless data transmission channel on the basis of channel quality indicators. By means of estimating the channel quality an accurate and momentary channel quality of a data transmission channel can be obtained on the basis of non-momentary CQIs that may be subject to measurement inaccuracies, delay or that may feature unacceptable quality due to e.g. high velocity movement of a mobile station. The invention provides determination of the quality and reliability of an obtained channel quality indicator and to select and to successively apply one or a plurality of various estimation procedures in order to determine an accurate and momentary channel quality indicator. Moreover, by making use of an iterative calibration procedure a CQI is determined such that a systematic offset between a defined transmission quality measure and an actually measured transmission quality can be effectively eliminated.