A terminal-based service identification method for a wireless cell-based communication system (300) that includes a home domain cell and at least one visitor domain cell. A roaming wireless subscriber terminal is assigned to the home domain cell and roams into a visitor cell (370). The method includes the steps of storing authorization data in the roaming wireless subscriber terminal to allow the roaming wireless subscriber terminal to operate in the visitor domain cell; transmitting the authorization data from the roaming wireless subscriber terminal to a server (420) in the visitor cell (370). The server receives the authorization data from the roaming wireless subscriber terminal and authorizes a service to be provided to the roaming wireless subscriber terminal in the visitor cell (370) in response to the authorization data. This provides the advantages that signalling between the home domain and the visited domain is minimized whilst enabling a user to be dynamically authorized to use services or levels of service within the communication system (300).