Abstract: Examples pertaining to secure transmission in mobile communications are described. A UE receives an RRC reconfiguration message from a master network node. The RRC reconfiguration message comprises information regarding candidate cells and predefined reconfigurations, and each candidate cell is associated with one predefined reconfiguration. The UE evaluates a triggering condition for at least one candidate cell to determine whether to trigger a conditional cell change procedure and performs the conditional cell change procedure to switch a PSCell associated with the apparatus to a target cell in an event that the triggering condition for the target cell is met. The UE derives a security key according to a counter value and a key of the master network node. The counter value is obtained from a sequence of distinct counter values of the target cell or of a target secondary node stored by the processor or is generated by the processor.

Abstract: In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be a UE. In certain configurations, the UE enters a first radio resource control (RRC) connection with a first base station of a first network. The UE receives, from the first base station, an indication that enables the UE to send a first request for deactivating or releasing resources used for communications with the first base station. In response to a determination to enter a second RRC connection with a second base station of a second network, the UE sends, to the first base station, the first request for deactivating or releasing the resources. The UE enters the second RRC connection with the second base station while maintaining the first RRC connection with the first base station.

Abstract: A method of L1/L2-based mobility with signaling optimization using base (reference) configuration and replaceable (delta) configuration for candidate cells is proposed. All candidates can be configured at different levels provided by Radio Resource Control (RRC) signaling. To support L1/L2-triggered mobility (LTM), there is a common base configuration for candidates, and the candidates are modelled as replaceable configurations which are delta configurations on top of the common base configuration (instead of UE's current RRC configuration). The common and replaceable configurations are also referred to as reference configuration and candidate delta configuration. The candidate delta configuration is applied on top of the reference configuration to form a complete candidate configuration for handover.

Abstract: Aspects of the disclosure provide a method to activate secondary cell group (SCG) selectively. For example, the method can include receiving a radio resource control (RRC) reconfiguration message including first and second radio resource configurations of first and second primary secondary cells (PSCells) and conditional PSCell addition (CPA) and conditional PSCell change (CPC) triggering conditions, setting a current triggering condition to be the CPA triggering condition, evaluating the current triggering condition and determining that the first PSCell satisfies the current triggering condition, and performing a CPA step to add the first PSCell as a current SCG, updating the current triggering condition to be the CPC triggering condition, the UE still keeping the first and second radio resource configurations and the CPA and CPC triggering conditions for subsequent CPC step, without releasing the second radio resource configuration and the CPA and CPC triggering conditions associated with the second PSCell.

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 service network utilizing a first RAT or a second service network utilizing a second RAT. The controller sends an indicator of a connection release request to the first service network via the wireless transceiver in response to terminating a first communication service with the first service network or in response to leaving the first service network for the second service network. Also, the controller releases a Radio Resource Control (RRC) connection with the first service network after sending the indicator of the connection release request.

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 service network utilizing a first RAT or a second service network utilizing a second RAT. The controller sends an indicator of a connection release request to the first service network via the wireless transceiver in response to terminating a first communication service with the first service network or in response to leaving the first service network for the second service network. Also, the controller releases a Radio Resource Control (RRC) connection with the first service network after sending the indicator of the connection release request.

Abstract: A method for expediting Secondary Cell (SCell) activation is proposed. Under the proposed enhanced direct SCell activation procedure, while adding an SCell to be activated state, the network can add transmission configuration indication (TCI) state information for the SCell in a radio resource control (RRC) signaling message, in addition to TCI state information for a list of candidate TCI states. Upon receiving the RRC signaling message, UE adds the SCell accordingly, and then activates the SCell based on the received TCI state information. Because there is no additional time required for receiving and processing the TCI state information via a media access control (MAC) control element (CE), the SCell activation time is reduced.

Abstract: A method for expediting Secondary Cell (SCell) or Primary cell of a secondary cell group (PSCell) addition or activation is proposed. A User Equipment (UE) receives a command that indicates adding or activating an SCell or a PSCell, wherein the command comprises information of a temporary Reference Signal (RS). The UE detects the temporary RS according to the information, and uses the temporary RS to add or activate the SCell or the PSCell.

Abstract: A method of UE-initiated radio resource control (RRC) connection release procedure in LTE/5G network is proposed. A UE is required to establish RRC connection and enter RRC_Connected state for data communication. However, power consumption from functions for UE mobility can be significant, especially in RRC_Connected state. It is thus desirable for the UE to be able leave the RRC_Connected state by triggering an RRC connection release procedure. The triggering conditions may include: 1) UE has no data transmission for quite some time; 2) UE is in low battery status; 3) UE has incoming voice/video call from another USIM; or 4) UE has outgoing voice/video call in another USIM.

Abstract: A method for handling a measurement configuration including: determining a measurement configuration, wherein the measurement configuration includes a measurement object and a plurality of reporting configurations; performing at least one first measurement for the measurement object, to generate at least one first measurement result; and transmitting the at least one first measurement result to a network device according to a reporting configuration of the plurality of reporting configurations in response to the reporting configuration being satisfied; wherein the plurality of reporting configurations correspond to the measurement object.

Abstract: A method of acquiring timing advance (TA) for neighbor cells to reduce latency and interruption for inter-cell mobility is proposed. A UE is configured with a set of active cells for fast cell-switching. To reduce handover interruption, UE performs early RACH for potential target cells and obtains the TA of the potential target cells. In one novel aspect, for overhead reduction, a single RACH preamble may be received by multiple cells. Using a single RACH preamble, UE acquires TA for multiple cells, aiming at reducing the interruption due to RACH during handover. In another novel aspect, UE reports DL reception timing difference between the serving cell and the neighbor cell, and then adjust the TA for the neighbor cell accordingly.

Abstract: Apparatus and methods are provided for sidelink relay-based UE-to-network communication. In one novel aspect, the relay UE performs delayed relay forwarding upon determining the remote UE is in the DRX cycle based on the PC5 configuration. The relay UE buffers the relay traffic and/or sends a suspending indication to the base station to request the base station to suspend the relay traffic to the remote UE. In another novel aspect, the relay UE monitors paging occasions configured for itself and receives paging message from the network intended for the remote UE in one non-connected RRC state. The relay UE sends a PC5 paging message to the remote UE that is in the non-connected RRC state through the established SL based on the received paging message. In one embodiment, the network stores the SL association between the relay UE and the remote UE to the network.

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 cellular station and a second cellular station. The controller continues to send or receive UP data to or from the first cellular station via the wireless transceiver after receiving a handover command message for a handover of the UE from the first cellular station to the second cellular station, and receives a Radio Resource Control (RRC) request message from the second cellular station via the wireless transceiver after sending a handover complete message to the second cellular station. Also, the controller detaches from the first cellular station in response to receiving the RRC request message.

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 base station. The controller is coupled to the wireless transceiver, and configured to receive an RRC reconfiguration message from the first base station via the wireless transceiver, and in response to the UE being configured to provide measurement gap requirement information of NR target bands, send an RRC reconfiguration complete message including the measurement gap requirement information to the first base station via the wireless transceiver.

Abstract: Apparatus and methods are provided to reduce mobility interruption time through dual-protocol stacks for mobility enhancement. In novel aspect, the UE configures a target protocol stack for a target gNB upon receiving a reconfiguration message from a source gNB, performs random access procedure and establishes RRC connection with the target gNB through the target protocol stack while simultaneously maintaining data transmission and reception with the source gNB, and releases the source RRC connection with the source gNB and performs data transmission and reception with the target gNB upon detecting one or more predefined release triggering event. In one embodiment, the target protocol stack includes a PHY layer, a MAC layer, and RLC layer, a PDCP and optionally a SDAP. In one embodiment, the UE enables a PDCP reordering, wherein the PDCP reordering is performed on PDCP packet data units received from the source and the target protocol stacks.

Abstract: A method, executed by a User Equipment (UE) communicatively connected to a Secondary Cell Group (SCG) of a mobile communication network, is provided. The method includes the following steps: receiving a first Radio Resource Control (RRC) message or a Media Access Control (MAC) Control Element (CE) including an indicator for suspension or resumption of the SCG or for deactivation or activation of a Primary Secondary Cell (PSCell) of the SCG from the mobile communication network; suspending SCG transmission for all radio bearers in response to the first RRC message or the MAC CE including an indicator for suspension of the SCG or deactivation of the PSCell; and resuming SCG transmission for all radio bearers in response to the first RRC message or the MAC CE including an indicator for resumption of the SCG or activation of the PSCell.

Abstract: Apparatus and methods are provided for multiple concurrent gap configuration. In one novel aspect, the UE obtains the concurrent gap configuration which configures a concurrent measurement gap and one or more associated usages for the concurrent measurement gap, configures the concurrent measurement gap. In one embodiment, the UE reports a UE concurrent gap support capability to the wireless network indicating a concurrent measurement gap is supported by the UE and/or indicates one or more associated usages supported by the UE. In another embodiment, a measurement prioritization is performed when the concurrent measurement gap overlaps with another MG. The measurement prioritization is based on a measurement priority indication from the NW or determined by the UE or based on a set of preconfigured multiple gap sharing factors indicating a set of percentages for each corresponding measurement gap.

Abstract: A method of providing UE-initiated PDCP status report to reduce packet latency under Multi-RAT Dual Connectivity (MR-DC) is proposed. UE initializes PDCP status report based on some predefined condition configured by the network. The PDCP status report indicates which PDCP SDU is still not received by the UE via one radio link control (RLC) entity, and the network can retransmit the missing PDCP SDU via another RLC entity quickly. The network can enable/disable the PDCP status report via PDCP control PDU or via radio resource control (RRC) signaling. The PDCP status can be used for re-transmission of PDCP SDU on another RLC entity. The PDCP status can also be used as an indication of issues on one RLC entity, resulting in duplication being activated thereafter. The PDCP status report should be sent to the RLC entity that does not suffer from the PDCP packet loss.

Abstract: A method of performing a group handover procedure in a layer 2 relaying architecture is proposed to meet the group handover timing constraints. A relay device and one or more remote devices are collectively relocated from a source network node to a target network node, where messages of the group handover procedure are selectively delayed or omitted to ensure synchronisation of the handover operations at the various devices.

Abstract: A method for recovering from Sidelink relay failure is provided. A relay User Equipment (UE) detects a Radio Link Failure (RLF) or a Handover (HO) failure associated with a first base station when providing a relay service for a remote UE to indirectly communicate with the first base station. The relay UE sends a first command to the remote UE to indicate suspension of the relay service. The relay UE performs a Radio Resource Control (RRC) re-establishment procedure with the first base station or a second base station based on a cell search result. The relay UE sends a second command to the remote UE to indicate that the relay service is associated with the first base station or the second base station with which the RRC re-establishment procedure is performed.