ng signal transmission. In Equation (10-20), SINRtarget is replaced with the sounding channel target SINR. The quality of sounding channel measurements is maintained by assigning different target SINR values according to the downlink SIR of each mobile station, i.e., a relatively higher target SINR is set for the MS with a higher downlink SIR. The SINRtarget for the sounding channel is calculated based on the values of SINR min (the minimum SINR requirement for the sounding channel), r (the IoT control factor for sounding channel), and SIRDL (the ratio of the downlink signal to interference power) with a and set to zero. Some of these parameters are signaled through the AAI_SCD MAC control message. In the case of simultaneous transmission of several uplink control channels, the transmission power of each channel is appropriately set in a certain order (i.e., HARQ feedback, PFBCH/SFBCH, synchronized ranging, sounding, traffic channels, bandwidth request) provided that the total transmit power does not exceed the maximum power limit of the MS (typically 24 dBm). The base uplink transmission Power Spectral Density (PSD) and the SIRD are two parameters that are measured and reported by the MS to the serving BS. The base uplink transmission PSD is derived from Equation (10-19) by setting SINR target and Poffset to zero. The PSD value is reported in 0.5 dBm steps ranging from -74 dBm to 53.5 dBm, and is encoded in 8 bits. The value of SIRD is encoded using 10 bits in 0.05 dB steps ranging from -10 dB to 41.15 dB. Link Adaptation Link adaptation schemes adaptively adjust over-the-air transmission parameters in response to a change of radio channel for both downlink and uplink. The IEEE 802.16m supports an Adaptive Modulation and Coding (AMC) scheme for downlink and uplink transmissions. The serving BS can adapt the MCS level based on the DL channel quality reports and HARQ feedback from the MS in the downlink. The transmit power of downlink control channels is adapted based on channel quality reports from the MS. The MI