A method comprising: obtaining, at a user equipment, information on a cell network slice support; determining, for the user equipment a network slice; and selecting one cell supporting the determined network slice based on the information.

A method, by a first node, for handling provision of an IMS service. A communications network comprises a first slice handling a first IMS service, and a second slice handling a second IMS service. The first node obtains, from a second node at least one of a first and a second indication. The first indication is of a first routing service instance for a third node handling the first service in the first slice. The second indication is of a second routing service instance for a fourth node handling the second service in the second slice. The first node routes a request, to one of the nodes with one of the proviso that when the request is for the first service, the routing is based on the first indication, and when the request is for the second service, the routing is based on the second indication.

A method and apparatus for acquiring a Radio Access Technology (RAT) of a serving cell, a method and apparatus for indicating a RAT of a serving cell, and devices are provided. The method for acquiring a RAT of a serving cell includes: receiving RAT indication information from the relay device, wherein the RAT indication information indicates RAT information of the serving cell where the relay device is located; determining, based on the RAT indication information, a RAT type adopted by a base station to which the serving cell belongs; and communicating with the base station using the RAT appropriate to the RAT type adopted by the base station.

Network Slice Selection Assistance information (NSSA1) may be signaled between U ser Equipment (UE) and a network. NSSA1 sent from the network to the UE may include, for example. Operating Frequency Band (OFB) for each Single NSSAI(S-NSSA1) in the NSSAI, as well as a Radio Access Technology (RAT) Frequency Selection Priority (RFSP) index, which the network configures as a part of UE access and mobility; subscription, during a UE registration procedure. RAT restrictions may be enhanced to indicate to the UE that certain slices are not accessible via certain RATs. A UE may be provided by the network with an alternative NSSAI and corresponding OFBs for each S-NSSAI thereby indicating to the UE that these S-NSSAI would have been allowed had they been requested. A UE may be able to choose an alternative Allowed NSSAI and send a registration update request to the network.

Network Slice Selection Assistance information (NSSA1) may be signaled between U ser Equipment (UE) and a network. NSSA1 sent from the network to the UE may include, for example. Operating Frequency Band (OFB) for each Single NSSAI(S-NSSA1) in the NSSAI, as well as a Radio Access Technology (RAT) Frequency Selection Priority (RFSP) index, which the network configures as a part of UE access and mobility; subscription, during a UE registration procedure. RAT restrictions may be enhanced to indicate to the UE that certain slices are not accessible via certain RATs. A UE may be provided by the network with an alternative NSSAI and corresponding OFBs for each S-NSSAI thereby indicating to the UE that these S-NSSAI would have been allowed had they been requested. A UE may be able to choose an alternative Allowed NSSAI and send a registration update request to the network.

A UE transmits a PDU session establishment request message including an S-NSSAI and a PDU session ID, and receives a PDU session establishment accept message including the S-NSSAI, the PDU session ID, a first cause value, a first back-off timer value, a first Session-AMBR IE, and a second Session-AMBR IE. The UE establishes a PDU session corresponding to the S-NSSAI, configures a back-off timer corresponding to the S-NSSAI to the first back-off timer value, and applies a data rate indicated by the second Session-AMBR IE to the PDU session while the back-off timer is running. In a case that the UE receives a PDU session modification command including the PDU session ID, a second cause value, a second back-off timer value, and a third Session-AMBR IE before expiration of the back-off timer, the UE, in a case that the second back-off timer value indicates other than 0, updates the back-off timer to the second back-off timer value, applies the data rate indicated by the third Session-AMBR IE to the PDU session, and updates, after expiration of the back-off timer, the data rate applied to the PDU session to the data rate indicated by the first Session-AMBR IE. This allows for provision of a communication unit for implementing a function related to management of a maximum number of UEs and/or a maximum number of PDU sessions connected for each network slice in a 5GS.

A UE transmits a PDU session establishment request message including an S-NSSAI and a PDU session ID, and receives a PDU session establishment accept message including the S-NSSAI, the PDU session ID, a first cause value, a first back-off timer value, a first Session-AMBR IE, and a second Session-AMBR IE. The UE establishes a PDU session corresponding to the S-NSSAI, configures a back-off timer corresponding to the S-NSSAI to the first back-off timer value, and applies a data rate indicated by the second Session-AMBR IE to the PDU session while the back-off timer is running. In a case that the UE receives a PDU session modification command including the PDU session ID, a second cause value, a second back-off timer value, and a third Session-AMBR IE before expiration of the back-off timer, the UE, in a case that the second back-off timer value indicates other than 0, updates the back-off timer to the second back-off timer value, applies the data rate indicated by the third Session-AMBR IE to the PDU session, and updates, after expiration of the back-off timer, the data rate applied to the PDU session to the data rate indicated by the first Session-AMBR IE. This allows for provision of a communication unit for implementing a function related to management of a maximum number of UEs and/or a maximum number of PDU sessions connected for each network slice in a 5GS.

A method disclosed herein includes registering, by a UE, with a same PLMN over a 3GPP access and a non-3GPP access. The method includes receiving, by the UE, a notification message from a CN of the PLMN over the non-3GPP access, in response to at least one communication service pending to be delivered to the UE over the 3GPP access. The method includes sending, by the UE, a notification response message to the CN over the non-3GPP access, in response to the received notification message. In order to avoid delay in acquiring downlink communication services, the method includes triggering, by the UE, the registration procedure with the CN to receive communication services over the 3GPP access in response to the UE entering the coverage of the 3GPP access.

A method disclosed herein includes registering, by a UE, with a same PLMN over a 3GPP access and a non-3GPP access. The method includes receiving, by the UE, a notification message from a CN of the PLMN over the non-3GPP access, in response to at least one communication service pending to be delivered to the UE over the 3GPP access. The method includes sending, by the UE, a notification response message to the CN over the non-3GPP access, in response to the received notification message. In order to avoid delay in acquiring downlink communication services, the method includes triggering, by the UE, the registration procedure with the CN to receive communication services over the 3GPP access in response to the UE entering the coverage of the 3GPP access.

Various aspects of the present disclosure generally relate to certificate based application descriptors for network slice selection. In some aspects, a user equipment (UE) may receive a first certificate associated with obtaining a network slice for executing an application. The UE may transmit, to a device, a request for the network slice with the first certificate, and receive an indication that the network slice is available to the UE for the application, based at least in part on the request. Numerous other aspects are provided.