A method and system for determining the synchronized value of a first counter of a wireless communication system serving a user station which moves at a time of handover from a first coverage area controlled by a first controller into a second coverage area controlled by a second controller. A value of the first counter is maintained in the first controller up to the time of the handover. During handover a request is sent to the user station for a constant value representing the difference between the first counter and a second counter, the value of the second counter being maintained in the second coverage area. At a later time the second controller receives an updated value of the second counter and determines an updated value of the first counter at that later time using the constant value.