Читать книгу Mobile Communications Systems Development - Rajib Taid - Страница 111

In the LTE or 5G system also, piggybacking of a signaling message, e.g. piggybacking an SM layer message to an MM layer message, is used. In the LTE/EPS, piggybacking of NAS messages is used for the bearer management procedure in the downlink direction. In the uplink direction, piggybacking of the NAS message is used only for transferring the initial NAS message during connection setup. For example, the LTE/EPS ATTACH Request message is send piggybacked with the RRCConnectionSetupComplete message over the LTE air interface between UE and E‐UTRAN.

Similarly, in the 5G NR system, the NAS layer RegistrationRequest (toward the 5G Core Access and Mobility Management Function (AMF)) message is piggybacked to the RRCSetupComplete message from a UE to the NG‐RAN.

 CN Signaling Messages