In a method and a transmitter data is transmitted to two mobile stations sharing the same frequency band and the same timeslot. The data is modulated using a quaternary symbol constellation. Further, the data is transmitted to two mobile stations multiplexed on a shared channel comprising two branches and the transmission power for the transmitted data is set in response to the relative gain of the two branches. Hereby, the total system interference is reduced. The method and transmitter further allows for a cellular radio system individual power control loops for the two sub-channels when the system uses MUROS.