The cellular system has a radio access network comprising base stations and a controller to which a wireless local area network is linked. A terminal is authenticated with the cellular system through the radio access network, and in response an authentication token allocated thereto. The allocated token is transmitted from the controller to the terminal through the radio access network. The allocated token and an identifier of the terminal are further transmitted from the controller to an authentication server accessible through said wireless network. The terminal is authenticated with the wireless network by verifying that the terminal possesses the token transmitted to said authentication server.