Читать книгу Mobile Communications Systems Development - Rajib Taid - Страница 119

In an end‐to‐end mobile communications network, one important function of the CN is to protect the real identity of an MS/UE while exchanging information over the air interface. The confidentiality of an MS/UE identity over the air interface is accomplished by allocating a temporary identity to it by the concerned CN element. Also, the temporary network identity is provided by the concerned network element which controls a particular service area. In the case of the GSM system, a VLR controls a location area; in the case of the GPRS system, an SGSN controls a routing area; and in the case of the LTE/EPS system, an MME controls a tracking area. Some of the temporary identities assigned to a mobile device by the concerned CN elements of GSM, GPRS, UMTS, and LTE networks are described below. For more information on these temporary identities, refer to TS 23.003 [30] and TS 23.060 [31].