Abstract: A network-based solution of supporting IP multimedia subsystem (IMS) call setup in a next generation system (5GS) is proposed. During an attach or registration area update procedure, a serving base station sends an indication to a UE indicating whether IMS voice over PS session is supported or not. Upon receipt of the indication that IMS VoPS is supported, the UE triggers an IMS registration procedure. However, when an MO/MT call happens, the network determines that the UE may be in conditions where voice service is not supported because the network is not able to provide a successful IMS VoPS over the current serving cell connected to 5G core network. The network then triggers a RAT change or a EPS fallback procedure such that the UE is handover to a target cell that supports IMS VoPS.

Abstract: A method of managing default QoS rules for PDU session is proposed. A PDU session defines the association between the UE and the data network that provides a PDU connectivity service. Each PDU session is identified by a PDU session ID, and may include multiple QoS flows and QoS rules. There can be more than one QoS rule associated with the same QoS flow. A default QoS rule is required to be sent to the UE for every PDU session establishment and it is associated with a QoS flow. Within a PDU session, there should be one and only one default QoS rule. In one novel aspect, UE behavior and error handling for proper QoS rule management is defined for PDU session establishment and modification procedures to enforce the one and only one default QoS rule policy.

Abstract: A method of defining ATtention (AT) commands for 5G session management operations is proposed. In one example, the AT command can be a set command for configuring a PDU session establishment procedure. Additional 5G parameters including PDU session ID, Single-Network Slice Selection Assistance Information (S-NSSAI), Service and Session Continuity (SSC) mode, access type, and Reflective QoS (RQ) indication are defined for AT command +CGDCONT to configure the PDU session. In another example, the AT command can be a read command for querying PDU session and QoS flow parameters. Additional 5G parameters including PDU session ID (PSI), QoS flow ID (QFI), S-NASSI, SSC mode, access type, and RQ timer are defined for AT command +CGCONTRDP or +CGSCONTRDP.

Abstract: Aspects of the disclosure provide an electronic apparatus and a method for wireless communication. The electronic apparatus can include processing circuitry. The processing circuitry can send one or more packet data unit (PDU) session release requests to a wireless communication network system to request a PDU session release procedure. In an embodiment, a timer is used for the one or more PDU session release requests. The processing circuitry can determine whether a network response is received from the wireless communication network system before the timer expires and whether a number of times that the timer expires reaches a predetermined number of times. The processing circuitry can locally release the PDU session when the network response is not received and the number of times that the timer expires reaches the predefined number of times.

Abstract: Aspects of the disclosure can provide an apparatus and method for operating a Protocol Data Unit (PDU) session associated with a non-3GPP access when the apparatus is to perform an inter-system change. The apparatus can include processing circuitry that is configured to connect to a first communication system over a 3GPP access and a non-3GPP access and switch the connection from the first communication system to a second communication system. Further, when in a release mode, the processing circuitry can release a PDU session that is in the first communication system over the non-3GPP access, and when in a transfer mode, the processing circuitry can transfer the PDU session that is in the first communication system over the non-3GPP access to a Packet Data Network (PDN) connection that is in the second communication system over a 3GPP access.

Abstract: A method of defining ATtention (AT) commands for 5G QoS management is proposed. AT commands for modifying PDU sessions, creating and modifying QoS flows and QoS rules, and for querying QoS flow and QoS rule parameters are defined for 5G networks. Specifically, the AT command can be a set command for triggering a PDU session modification procedure and thereby creating and modifying QoS flows and QoS rules. For example, AT command +C5GQOS is introduced for creating and modifying QoS flows, AT command +C5GQOSRDP is introduced for retrieving QoS flow parameters, AT command +CGTFT can be reused for creating and modifying QoS rules, and AT command +CGTFTRDP can be reused for retrieving QoS rule parameters.

Abstract: Aspects of the disclosure can provide an apparatus and method for voice domain selection (VDS). A processing circuitry of user equipment (UE) is configured to receive an indication that an internet protocol (IP) multimedia core network subsystem (IMS) voice is unsupported over a 3GPP access, but is supported over a non-3GPP access in a first communication system. Then, the processing circuitry is configured to register to an IMS via the non-3GPP access in the first communication system and perform an IMS voice service over the non-3GPP access in the first communication system. The processing circuitry of the UE is further configured to switch to a second communication system when voice domain management (VDM) is set to the second communication system.

Abstract: A method of managing default QoS rules for PDU session is proposed. A PDU session defines the association between the UE and the data network that provides a PDU connectivity service. Each PDU session is identified by a PDU session ID, and may include multiple QoS flows and QoS rules. There can be more than one QoS rule associated with the same QoS flow. A default QoS rule is required to be sent to the UE for every PDU session establishment and it is associated with a QoS flow. Within a PDU session, there should be one and only one default QoS rule. In one novel aspect, UE behavior and error handling for proper QoS rule management is defined for PDU session establishment and modification procedures to enforce the one and only one default QoS rule policy.

Abstract: A User Equipment (UE) including a wireless transceiver and a controller is provided. The wireless transceiver performs wireless transmission and reception to and from a first cell of a first Public Land Mobile Network (PLMN) and a second cell of a second PLMN. The controller performs a Location Update (LU) procedure with the second cell via the wireless transceiver in response to an inter-PLMN handover of the UE from the first cell of the first PLMN to the second cell of the second PLMN, and obtains one or more Session Management (SM), Evolved SM (ESM), or 5GSM parameters of the second PLMN from a Protocol Data Unit (PDU) session modification command, a bearer modification command, or a Packet Data Protocol (PDP) context modification command which is received from the second cell via the wireless transceiver in response to completing the LU procedure caused by the inter-PLMN handover.

Abstract: A User Equipment (UE) including a wireless transceiver and a controller is provided. The wireless transceiver performs wireless transmission and reception to and from a service network. The controller receives a response message of a Non-Access Stratum (NAS) procedure for establishing or modifying a Protocol Data Unit (PDU) session from the service network via the wireless transceiver, and determines that Reflective Quality of Service (RQoS) is not applied for the PDU session in response to the response message including an RQoS timer (RQ timer) value set to zero or deactivated.

Abstract: A mobile communication device including a wireless transceiver and a controller is provided. The wireless transceiver performs wireless transmission and reception to and from a first network supporting only Packet-Switched (PS) services or a second network supporting Circuit-Switched (CS) services. The controller receives a rejection message of a Tracking Area Updating (TAU) procedure from the first network via the wireless transceiver when a Circuit Switch Fallback (CSFB)-related call originated from or terminated to the mobile communication device is pending, determines whether the rejection message includes a predetermined rejection cause, and in response to the rejection message including the predetermined rejection cause, selects the second network to make the CSFB-related call via the wireless transceiver without re-attaching to the first network.

Abstract: Aspects of the disclosure can provide an apparatus and method for communicating with core network of a fifth generation system. The method includes transmitting, by a processing circuitry of a user equipment, a non-access stratum transport message to the core network to initiate a non-access stratum transport procedure with the core network, and receiving an indication message from the core network when a network function of the core network is unable to process the non-access stratum transport message, wherein the indication message includes at least one of a payload type, a cause value, and timer information.

Abstract: Aspects of the disclosure provide an electronic apparatus and methods for wireless communication. The electronic apparatus can include processing circuitry configured to identify, during an inter-system change of the electronic apparatus from a source network system to a target network system, at least one source session bearer between the electronic apparatus and the source network system. The processing circuitry can further map the at least one identified source session bearer to at least one target session bearer based on a mapping relationship that matches the at least one identified source session bearer with the at least one target session bearer to be established between the electronic apparatus and the target network system.

Abstract: A method of maintaining a proper forbidden tracking area identifier (TAI) list is proposed. A UE receives a service area list comprising one or more allowed tracking areas. The service area list may be carried by a configuration update command. UE compares if any of the allowed tracking area having a matching TAI in the forbidden TAI list. Accordingly, UE removes any allowed tracking areas having a matching TAI from the forbidden TAI list. In one embodiment, UE sends a REGISTERATION REQUEST message to initiate a registration procedure. In response, UE receives a REGISTRATION ACCEPT message, which may also carry a service area list. UE may remove the allowed tracking area having a matching TAI from the forbidden TAI list. However, if UE is registered for emergency services, then UE shall not remove the allowed tracking area from the forbidden TAI list.

Abstract: A method of providing assistance information to improve the performance of Public Land Mobile Network (PLMN) selection is proposed. UE starts to perform PLMN selection procedure and searches for the first cell. The first cell can be an LTE cell or an NR cell served by a first base station. UE receives assistance information via system information broadcasted by the first base station. The assistance information comprises frequency band of NR/LTE cells, PLMN ID, subcarrier spacing (SCS) for NR cells, and RAT/system priority. UE then determines its PLMN/RAT preference, e.g., based on the availability of NR cells or LTE ENDC cells. Finally, UE continues the PLMN selection procedure searching for NR cell or LTE cell based on the assistance information.

Abstract: Various solutions for avoiding circuit-switched call drop with respect to user equipment and network apparatus in mobile communications are described. An apparatus transmits a non-access stratum (NAS) message in a NAS signaling connection. The apparatus receives a NAS response message. The apparatus initiates a timer to control the NAS signaling connection. The apparatus further receives a circuit-switched (CS) service notification. The apparatus then stops the timer and execute a CS service procedure.

Abstract: Various examples pertaining to reflective quality of service (QoS) control in wireless communications are described. A user equipment (UE) receives from a wireless network control signaling that activates support of reflective QoS by the UE. The UE determines whether a predefined condition exists. The UE then indicates to the wireless network a change in a capability of the UE to support the reflective QoS responsive to the determining indicating that the predefined condition exists. When the UE receives from the wireless network control signaling that activates support of reflective QoS by the UE, the UE deletes one or more UE-derived QoS rules among a plurality of active UE-derived QoS rules each with a respective reflective QoS (RQ) timer running.

Abstract: A method of improving initial IMS registration after 403 Forbidden response is proposed. A UE sends a SIP register to an IMS server for initiating IMS registration. The initial IMS registration fails and the UE receives a SIP message with a 403 Forbidden response code. In the 403 Forbidden response code, the IMS server includes an XML body and uses the <reason> header value of the XML body to indicate an error type (e.g., temporary or permanent) followed by a retry-after timer value. As a result, the network can indicate to UE whether the IMS registration rejection is permanent or is due to some temporary internal failure. By adding the retry-after timer value, the network can indicate to UE when to retry the next IMS registration.

Abstract: Various solutions for avoiding circuit-switched call drop with respect to user equipment and network apparatus in mobile communications are described. An apparatus may transmit a non-access stratum (NAS) message in a NAS signaling connection. The apparatus may receive a NAS response message. The apparatus may initiate a timer to control the NAS signaling connection. The apparatus may further receive a circuit-switched (CS) service notification. The apparatus may stop the timer and execute a CS service procedure.

Abstract: Apparatus and methods are provided for sim-less subscription mechanism for mobile cellular networks. In novel aspect, the mobile device supporting the e-SIM is provisioned with the assistance the UE by obtaining subscription information from the UE. In one embodiment, UE retrieves an ID from the mobile device. The UE sends a subscription request to the e-SIM platform, wherein the subscription request includes information of the retrieved ID of the mobile device and the subscription information of the UE. In another embodiment, the mobile device retrieves subscription information from the UE. The mobile device sends a subscription request to the e-SIM platform, wherein the subscription request includes information of the subscription information retrieved from the UE and the ID of the mobile device. The mobile device receives a subscription response from the e-SIM platform and enables the mobile device through mobile device's e-SIM based on the subscription response.