Transmission power levels of uplink/downlink communication is controlled in a wireless communication system. A receiving station produces and provides to a transmitting station power control information based upon received signals from the transmitting station. A measured block error rate (BLER.sub.msr) is obtained from the number of erroneous blocks in a sliding window of the last N received data blocks and SIR adjustments are set based upon the BLER.sub.msr and a target BLER (BLER.sub.target). A target SIR of received signals is adjusted according to the SIR adjustments.