Abstract: A UE performs up to a threshold number of attempts to transmit a default capability message to a base station, the default capability message representing a default set of CA combinations supported by the UE. If transmission is unsuccessful, the UE switches to a compact capability mode in which the UE attempts to transmit compacted UE capability messages representing successively smaller subsets of the default set of CA combinations until either a capability message is successfully received by the base station or a second threshold number of unsuccessful transmission attempts is performed. To facilitate configuration of an initial compacted capability message, the UE maintains a PC list that lists one or more cells that have been identified previously as incapable of receiving default-sized capability messages and that further identifies a representation of a limited subset of CA combinations to include in capability messages sent to a corresponding listed cell.

Abstract: In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be a UE. The UE establishes a connection with a base station on a cell of the base station. The UE connects, through the cell, to a packet data network (PDN) gateway to access a PDN. The UE communicates with a security gateway via the PDN gateway and the PDN. The UE transfers, using a first source IP address, a secure tunnel between the UE and the security gateway initiated over a wireless access network to the PDN accessed through the cell.

Abstract: A method for handling network feature capabilities is provided. The method includes a UE determining whether a first access network with a first access type and a second access network with a second access type are registered on the same PLMN; if the first access network and the second access network register on the same PLMN, the UE determines whether a first registration procedure over the first access network occurred earlier than the second registration procedure over the second access network. The first registration procedure corresponds to first setting values for a plurality of network feature capabilities and the second registration procedure corresponds to second setting values for the network feature capabilities. If the first registration procedure over the first access network occurred earlier than the second registration procedure over the second access network, the UE adopts the second setting values for the network feature capabilities.

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: In an aspect of the disclosure, an apparatus is provided. The apparatus connects to a security gateway via a packet data network (PDN) gateway. The apparatus further establishes a secure tunnel between the apparatus and the security gateway using a first source IP address.

Abstract: A method for handling network feature capabilities is provided. The method includes a UE determining whether a first access network with a first access type and a second access network with a second access type are registered on the same PLMN; if the first access network and the second access network register on the same PLMN, the UE determines whether a first registration procedure over the first access network occurred earlier than the second registration procedure over the second access network. The first registration procedure corresponds to first setting values for a plurality of network feature capabilities and the second registration procedure corresponds to second setting values for the network feature capabilities. If the first registration procedure over the first access network occurred earlier than the second registration procedure over the second access network, the UE adopts the second setting values for the network feature capabilities.

Abstract: A method for handling a PDN disconnection request performed by a communications apparatus communicating with a network device includes transmitting a PDN disconnect request message to the network device to request to disconnect a predetermined PDN connection; receiving a PDN disconnect reject message from the network device; obtaining a reject cause carried in the PDN disconnect reject message; and locally deactivating all other PDN connection(s) other than the predetermined PDN connection when the reject cause carried in the PDN disconnect reject message indicates that the last PDN disconnection is not allowed.

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: 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 dual SIM user equipment and a re-synchronizing method thereof are provided. The dual SIM user equipment includes a single radio frequency module, a first SIM and a second SIM. The first SIM connects with a first network via utilizing the single radio frequency module at first. The second SIM then connects with a second network via utilizing the single radio frequency module. The first SIM monitors the second SIM for determining that the second SIM disconnects from the second network. The first SIM then transmits a synchronization information to the first network for re-synchronizing to the first network while the first SIM determines that there is no data to be transmitted to the first network.

Abstract: A method of performing volunteer domain-change to support multiple services with service continuity in a heterogeneous network is proposed. A user equipment (UE) establishes a first connection for transmitting and receiving voice or data in a first service domain in a heterogeneous network. The UE is equipped with one or multiple radio frequency (RF) transceivers. The UE triggers a volunteer domain-change of the first connection from the first service domain to a second service domain based on a detected condition. The detected condition indicates that a second connection is not supported in the first service domain, establishing the second connection failed in the first service domain, or establishing the second connection is predicted to fail in the first service domain. The UE then establishes the second connection for transmitting and receiving voice or data in the second service domain while simultaneously continuing the first connection without service interruption.

Abstract: A solution for synchronizing capability and registration status between a user equipment (UE) and a network application server is provided. After a UE registers with an IMS/RCS server for SIP-based application services, the UE capability and registration status is synchronized between the UE and the network. Later, the UE capability may change and the UE will try to send a SIP message to the network with an updated UE capability. However, error may occur due to UE out of service or network error, which requires the UE to re-sync with the network. Upon detecting a re-sync condition, the UE will then trigger re-sending the SIP message to the network or releasing the PDN connection such that the updated UE capability and registration status will be synchronized with the network.

Abstract: A solution of establishing a data radio bearer via location update such that a user equipment (UE) can synchronize the UE capability with a network application server is provided. When a UE location changes, the UE will send a location update request to the network for such change including RAT change or service capability change etc. The UE can notify the network to establish the DRB by setting a flag in the location update request while in RRC Idle mode. The UE will set this flag when there is pending uplink data, e.g., a new SIP REGISTER message. As a result, the network can establish the DRB upon receiving the location update request, and then the UE is able to send the new SIP REGISTER message to the application server to synchronize the UE capability without incurring additional delay.

Abstract: A method of performing volunteer domain-change to support multiple services with service continuity in a heterogeneous network is proposed. A user equipment (UE) establishes a first connection for transmitting and receiving voice or data in a first service domain in a heterogeneous network. The UE is equipped with one or multiple radio frequency (RF) transceivers. The UE triggers a volunteer domain-change of the first connection from the first service domain to a second service domain based on a detected condition. The detected condition indicates that a second connection is not supported in the first service domain, establishing the second connection failed in the first service domain, or establishing the second connection is predicted to fail in the first service domain. The UE then establishes the second connection for transmitting and receiving voice or data in the second service domain while simultaneously continuing the first connection without service interruption.

Abstract: A method for handling a PDN disconnection request performed by a communications apparatus communicating with a network device includes transmitting a PDN disconnect request message to the network device to request to disconnect a predetermined PDN connection; receiving a PDN disconnect reject message from the network device; obtaining a reject cause carried in the PDN disconnect reject message; and locally deactivating all other PDN connection(s) other than the predetermined PDN connection when the reject cause carried in the PDN disconnect reject message indicates that the last PDN disconnection is not allowed.