Within the UE, if dedicated signaling from the RAN node to the UE is used to indicate that NSSAI information is required in the RRC connection establishment signaling for the service request procedure, such as the second solution, the NAS layer can send the NSSAI information to the AS layer and the AS layer can decide which information to include in the RRC signaling, for example as in RRC msg 5, such as all accepted slice IDs or the particular slice ID relevant for this service request as indicated by the NAS to the Access Stratum.

The potential benefits of the proposed solutions can include the ability to configure the UEs for sending NSSAI information in the Access Stratum connection establishment signaling caused by a service request in a flexible manner, such as including or changing the broadcasted SI, and for limited topological locations, such as for a single cell or group of cells in the registration area. Such a configuration of the UEs can be performed based on the network operator needs and regional load conditions.

It is noted that the disclosed solution(s) are described mainly using New Radio (NR) RAT terminology, but the solution(s) are not limited to NR and may also apply to other radio access technologies (RATs) or communication systems, e.g. LTE/EPS, or UTRAN/UMTS, etc.