Abstract: A method for identifying a mobile communications device in a mobile communications network is provided. The method comprises determining an identifier for a mobile communications device, the identifier comprising at least one of a first field, a second field, and a third field; including in the first field a mobile country code (MCC) for identifying a country to which the mobile communications device belongs; including in the second field a mobile network code (MNC) for identifying a network to which the mobile communications device belongs in the country; including in the third field a mobile station identification number (MSIN) for identifying the mobile communications device in the network; and including padding values in the third field, when the length of the MSIN is less than the length of the third field.