Patent ID: 7058404

Claim:
Method for performing a blind handover in intersystem and interfrequency mobile communication systems, whereby a mobile station is adapted for being supplied with radio signals from base stations of a first mobile communication system and base stations of a second mobile communication system, comprising the steps of: making a mandatory request of the mobile station to perform a measurement of propagation times of the radio signals being transmitted via an air interface from the base stations of the first mobile communication system to the mobile station by providing the mobile station with specific signal level threshold values that compel a position measurement, measuring of propagation times of the radio signals by the mobile station, transmitting the measured propagation times one of the first base stations of the first mobile communication system, determining on the part of the first mobile communication system the residence site of the mobile station on the basis of the propagation time measurement data, selecting, based on the determined residence site of the mobile station and, with the aid of a data base at least one suitable base station of the second communication system for an intersystem or interfrequency handover, transmitting data of the selected base station required for a handover from the first mobile communication system to the mobile station, and performing the handover by the mobile station from a base station of the first mobile communication system to the selected base station of the second mobile communication system ( 20 ).