A method for access to a Core Network CN via an Unlicensed Mobile Access Network/Generic Access Network UMAN/GAN, by a dual mode Mobile Station MS supporting access to said CN either via said UMAN/GAN or via a Radio Access Network RAN, said method comprising the steps of, in a non active state of said MS: detecting if said MS is under coverage of both UMAN/GAN and RAN, if it is detected that said MS is under coverage of both UMAN/GAN and RAN, selecting a RAN cell for camping on by the MS.