Parameters of radio propagation between a mobile terminal and at least one fixed transceiver are measured. Report messages indicating at least a part of the measured parameters, in accordance with a mode of reporting specified by the radio network controller are transmitted to the radio network controller. An estimate of speed of movement of the mobile terminal is obtained at the radio network controller. The report messages are processed at the radio network controller so as to determine, by taking account of the said estimate of speed, a mode of reporting to be specified for a part at least of the report messages.