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.

The present disclosure relates to a communication technique that combines a 5G communication system for supporting a higher data transmission rate than a 4G system with IoT technology, and a system therefor. The present disclosure may be applied to intelligent services (e.g. smart homes, smart buildings, smart cities, smart cars or connected cars, healthcare, digital education, retail businesses, security and safety-related services, etc.) on the basis of 5G communication technology and IoT-related technology. A method performed by a session management function (SMF) entity in a communication system, according to one embodiment of the present disclosure, may comprise the steps of: performing a packet data unit (PDU) session establishment procedure; identifying a QoS flow generated for ultra reliable low latency communication (URLLC) in a PDU session; identifying whether an indicator indicating that the PDU session is an Always-on PDU Session has ever been transmitted to a terminal; and when it is identified that the indicator has not been transmitted to the terminal, transmitting the indicator to the terminal.

A method of signaling enhancement for an always-on PDU session is provided. A User Equipment (UE) transmits a Non-Access Stratum (NAS) request message to a mobile communication network. The NAS request message includes an Always-on PDU Session Requested (APSR) Information Element (IE). The UE receives a NAS response message including an Always-on PDU Session Indication (APSI) IE from the mobile communication network. The APSI IE includes a time length indicator. In response to the APSI IE indicating that the always-on PDU session is not allowed, the UE starts a timer based on the time length indicator and retransmits the NAS request message to the mobile communication network when the timer expires.

A method of handling invalid PDU session during handover procedure between non-3GPP access and 3GPP access in a mobile communication network is proposed. A UE establishes a PDU session over a first RAT, and then tries to handover the PDU session from the first RAT to a second RAT. However, at the network side, the PDU session over the first RAT does not exist anymore and the network considers the PDU session to be invalid. The network thus sends a PDU session establishment reject message back to the UE, with a 5GSM status message cause value #54 indicating “PDU session does not exist”. At the UE side, the PDU session over the first RAT is still valid (e.g., not inactive). In order to resynchronize with the network, the UE performs a PDU session release procedure to release the PDU session over the first RAT.

Systems, methods and computer software are disclosed for providing multi-User Equipment (UE) and multi-message support in tunnel management messages. In one embodiment, a method is disclosed, comprising: determining, for a first node and a second node using GPRS Tunneling Protocol (GTP) tunneling support for UE management, if the first node and the second node support multi-UE messaging; when the first node and the second node support multi-UE messaging, then switching to multi-UE multi-messaging mode wherein a chain of messages are formed; and when at least one of the first node and second node do not support multi-UE messaging, then using conventional tunnel management messaging.

One aspect provides a method performed by a radio access network node in a telecommunications network. The method comprises: responsive to detection of a trigger event associated with a wireless device having a connection to the telecommunications network via the radio access network node or seeking to establish a connection to the telecommunications network via the radio access network node, transmitting, directly to a user plane core network node, a message initiating establishment of a user-plane tunnel for the connection between the radio access network node and the user plane core network node. The message comprises one or more of: an indication of an identifier of the wireless device; and an indication of an identifier of a session for the wireless device, and further comprises an indication of a downlink tunnel endpoint identifier of the radio access network node.

An information processing method and a terminal are provided, so as to solve a problem how to implement duplication of a sidelink communication interface when SLRB configuration is configured or preconfigured by a network and LCID is selected by the terminal. The method includes: obtaining target information, where the target information is configured to configure a PDCP duplication for a SLRB; determining a quantity of RLC entities corresponding to the SLRB PDCP duplication according to the target information; and determining a LCID corresponding to each RLC entity according to the quantity of the RLC entities corresponding to the SLRB PDCP duplication.

A terminal apparatus for communicating with a base station apparatus is provided. The terminal apparatus includes a receiver configured to receive a Radio Resource Control (RRC) reconfiguration message including a parameter related to a first configuration from the base station apparatus, and a processing unit configured to perform configuration in accordance with the RRC reconfiguration message received. In a case that a first timer of an RRC protocol expires, a radio link failure of a source primary cell is not detected, and configuration related to Dual Active Protocol Stack (DAPS) handover is performed for the terminal apparatus, the processing unit reconfigures all of state variables configured for a Radio Link Control (RLC) entity of a Signaling Radio Bearer (SRB) in the source primary cell to respective initial values, resumes the SRB suspended in the source primary cell, and transmits an RRC message for notifying the base station apparatus that the DAPS handover has failed.

Aspects relate to a relay device detecting a change in a protocol data unit (PDU) session configuration that the relay device has established for a user equipment (UE) that accesses a network via the relay device. Upon detecting this change, the relay device signals an indication of the change to the UE. Aspects also relate to UE that is connected to a relay device and that reselects an interworking function (e.g., a non-3.sup.rd Generation Partnership Project interworking function (N3IWF)). In some examples, the UE receives an indication from the relay device that a serving relay PDU session configuration has changed and, in response, the UE selects a new interworking function.

Aspects relate to a relay device detecting a change in a protocol data unit (PDU) session configuration that the relay device has established for a user equipment (UE) that accesses a network via the relay device. Upon detecting this change, the relay device signals an indication of the change to the UE. Aspects also relate to UE that is connected to a relay device and that reselects an interworking function (e.g., a non-3.sup.rd Generation Partnership Project interworking function (N3IWF)). In some examples, the UE receives an indication from the relay device that a serving relay PDU session configuration has changed and, in response, the UE selects a new interworking function.