Patent ID: 8880073

Claim:
A method implemented by a Mobile Management Entity, MME, for preventing a circuit switched, CS, domain call of a user equipment, UE from being dropped during a handover procedure, where the UE registered with one of a plurality of Generic Access Network Controllers, GANCs, based on Long-Term Evolution, LTE, and Generic Access Network, GAN, technology, the method implemented by the MME comprising the steps of: controlling, by the MME, a bearer used within the CS domain call of the UE which involves the registered GANC, where the registered GANC holds a UE GAN registration context and the CS domain call for the UE; and upon the UE moving towards a GSM Radio Access Network/UMTS Radio Access Network, GERAN/UTRAN, selecting, by the MME, one of the plurality of GANCs based on a GERAN/UTRAN cell identifier or a Location Area Identifier, LAI, associated with a location of the UE when the UE moves towards the GERAN/UTRAN, and sending, by the MME, a handover request to the selected GANC which checks to see if the UE GAN registration context and the CS domain call for the UE are held therein where if the result is yes then the selected GANC handles the handover request for the CS domain call of the UE otherwise the selected GANC forwards the handover request to other GANCs which could possibly hold the UE GAN registration context and the CS domain call for the UE and the one of the other GANCs which holds the UE GAN registration context and the CS domain call for the UE handles the handover request for the CS domain call of the UE.