In radio transmission systems with point-to-point and point-to-multipoint topology a master station and one or several terminal stations are defined as well as a downstream channel from the master station to the terminal stations and an upstream channel from the terminal stations to the master station. In such systems, in order to send traffic to several terminal stations, the downstream channel is used by the master station in time division multiplexing.In some cases, the modulation type and the forward error correction, jointly called phy mode, depend on the addressed terminal. These systems are called adaptive phy mode systems.The present invention relates to adaptive phy mode systems, and it defines a power control technique for the terminal stations that also commands the phy mode switching and optimizes the system in terms of coverage, capacity and interference. In particular the terminal stations transmit with the several phy modes so that the signals are received at the master station making a performance related parameter equal. Then a hysteresis based on two different parameters (received power and available unused transmit power) is defined which regulates the phy mode switching.