Abstract: A method for assigning a location area to a mobile device for use in circuit switched fallback from a first radio access network to a second radio access network. Two counters are implemented at the eNode B—a first counter to count the numbers of times a mobile reports a given last-used location area code and a second counter for counting the numbers of certain unique combinations of location area code and further identifying data. Whenever the eNode B receives a signal incorporating a location area code, checking the respective first counter for that code and conditionally incrementing the first counter such that if the first counter is below a predefined threshold the first counter is incremented. If the first counter is equal to the threshold, obtaining further identifying data in addition to the location area code and incrementing the corresponding second counter.