Method and apparatus for handover control in a satellite based telecommunications system

A method and apparatus are provided for controlling mobile and base stations (14 and 16) during satellite (12) based telecommunications to perform scheduled handovers between two communications channels (26 and 27). The base station (16) determines when a handover will be necessary. Once determined, the base station (16) generates a handover scheduling command (node #4) which includes a scheduled handover time representing a time in the future at which the handover will occur. The handover scheduling command is transmitted over the first channel to the mobile station (14). Upon receipt of the handover scheduling command, the mobile station (14) performs steps necessary to establish a second communications link over a second channel (27), prior to the scheduled handover time. At the scheduled handover time (node #21), the mobile and base stations (14 and 16) have established the second communications link on the second channel (27). To establish the second channel the mobile station calculations of the second channels frequency, timing offset and power level (node #11). By using a scheduled handover process, the mobile and base stations (14 and 16) avoid the production of interference and breaks within a conversation transmitted therebetween.