Network-triggered inter-cell mobility

Abstract

In wireless communication, devices may change, add, or handover between cells of network access for inter-cell mobility. This may involve Layer 1 and / or Layer 2 (L1 / L2) signaling for a user equipment (UE) moving between cells in a network. The signaling can reduce mobility interruption time and improve handover robustness. The movement may be triggered by the network or the UE. Layer 1 and / or Layer 3 (L1 / L3) measurements are utilized for inter-cell mobility. The mobility may be coordinated based on interactions between a centralized unit (CU) and a distributed unit (DU). This procedure can reduce interruption time and improve reliability.

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates generally to wireless communications and, more particularly, to improved signaling for inter-cell mobility in mobile device communication systems. [Background technology]

[0002] Wireless communication technologies are leading the world towards an increasingly connected and networked society. Wireless communication relies on efficient network resource management and allocation between user mobile stations and radio access network nodes, including but not limited to radio base stations. Next generation networks are expected to provide high speed, low latency, and ultra-reliable communication capabilities to meet the demands from various industries and users. User mobile stations or user equipment (UE) are becoming more complex, and the amount of data communicated is continuously increasing. To improve communication, meet the reliability requirements of vertical industries, and support next generation network services, communication improvements should be made. Summary of the Invention [Problem to be solved by the invention]

[0003] The present specification relates to a method, system and apparatus for Layer 1 and / or Layer 2 (L1 / L2) signaling for a user equipment (UE) moving between cells in a network. The signaling can reduce mobility interruption time and improve handover robustness. The movement may be triggered by the network or the UE. Layer 1 and / or Layer 3 (L1 / L3) measurements are utilized for inter-cell mobility. The mobility may be coordinated based on interactions between a centralized unit (CU) and a distributed unit (DU). [Means for solving the problem]

[0004] In one embodiment, a wireless communication method includes receiving a configuration message including a plurality of candidate cells having configuration and cell identification ("ID") information for each candidate cell; sending a measurement report including at least one of Layer 1 ("L1") or Layer 3 ("L3") measurements for at least one of the candidate cells; receiving a command identifying at least one of the candidate cells based on the measurement report; and sending a communication to the identified at least one candidate cell based on the command and the configuration of the identified candidate cell.

[0005] The measurement reports and communications are sent from a user equipment ("UE") to a base station, where the UE receives configuration messages and commands from the base station. The commands are layer 1 or layer 2 ("L1 / L2") signaling, and the communications sent to the identified candidate cells are L1 / L2 signaling, where the L1 signaling includes at least one of downlink control information ("DCI"), uplink control information ("UCI"), and physical layer acknowledgement ("ACK") signaling, and further, the L2 signaling includes a medium access control element ("MAC CE"). The commands include cell ID information of the identified candidate cells that are to be activated. The cell ID information includes at least one of a candidate cell configuration index, a serving cell ID, a physical cell identity ("PCI"), a PCI and frequency, a reference signal ("RS") ID associated with the candidate cell, or a transmission configuration indicator ("TCI") state ID associated with the candidate cell. The candidate cells include separate lists for any of the candidate cells to be configured as a special cell ("SpCell") or any of the candidate cells to be configured as a secondary cell ("SCell"), and the identification is based on the separate lists. The candidate cells include a list in which each of the candidate cells can be configured as a special cell ("SpCell") or a secondary cell ("SCell"). The candidate cells include a list in which each of the cells can be configured as a candidate cell for both a special cell ("SpCell") and a secondary cell ("SCell").Measurement reporting is triggered from the UE based on at least one of the following conditions: an event met based on Layer 1 measurements of at least one candidate cell, an out of sync indication from a serving cell or special cell ("SpCell"), or a failure of the serving cell or SpCell. The command includes at least one of: a timing advance ("TA") value or a compensation TA value for the identified candidate cell; a cell Radio Network Temporary Identifier ("C-RNTI") for the identified candidate cell; an activation DL / UL bandwidth part ("BWP") ID for the identified candidate cell; an initial TCI state for the identified candidate cell; a serving cell ID for the identified candidate cell; an indication indicating whether the RACH procedure to the identified candidate cell is skipped; an indication indicating whether the UE should maintain a connection with the current serving cell; an indication indicating whether the identified candidate cell is activated as a special cell ("SpCell"); and an indication indicating whether PDCP overlap is activated after accessing the identified candidate cell.

[0006] The method further includes activating a stored cell configuration of the identified candidate cell, applying a stored cell configuration of the identified candidate cell, or performing mobility from a current serving cell to the identified candidate cell. The method further includes starting a timer for the activation or mobility. The timer is a media access control ("MAC") layer timer or a radio resource control ("RRC") layer timer. The timer is stopped based on at least one of a condition including a successful transmission of a communication to the identified candidate cell, a failure of a current serving cell, or information from a higher layer indicating a timer stop. The method further includes determining a failure for the activation or mobility based on an expiration of the timer. The method further includes reporting a failure of the activation or the mobility to the base station, the failure being reported via MAC CE or RRC signaling, notifying a higher layer of the failure of the activation or the mobility, or selecting another cell among the candidate cells and performing another activation of the selected another cell or another mobility to the selected another cell. The method further includes activating the identified candidate cell, where a serving cell identity is set to zero if the identified candidate cell is activated as a primary cell ("PCell"), and where the serving cell identity is set based on a received identity for the identified candidate cell if the identified candidate cell is activated as a secondary cell ("SCell") or primary secondary cell ("PSCell"). The method further includes receiving a message from the base station, and removing the stored candidate cell configuration based on receiving the message.The method further includes receiving a message from the base station including at least one of an indicator to remove all stored candidate cell configurations or to remove a portion of the candidate cells, and removing the stored candidate cell configurations based on the indicator or the indicated candidate cells to be removed, the message being at least one of a handover command, a primary secondary cell ("PSCell") addition or / modification command, or a message ordering a release of a radio resource control ("RRC") connection or a suspension of an RRC connection. The method further includes receiving a message from the base station to resume a suspended radio resource control ("RRC") connection, the message including one or more candidate cells to be resumed, activated, maintained, or restored. A candidate cell refers to a candidate cell group, where the candidate cell group is at least one of a candidate master cell group ("MCG") or a candidate secondary cell group ("SCG").

[0007] In another embodiment, a wireless communication method includes transmitting a configuration message including a plurality of candidate cells having configuration and cell identification (ID) information for each of the candidate cells, receiving a measurement report including at least one of Layer 1 ("L1") or Layer 3 ("L3") measurements for at least one of the candidate cells, transmitting a command identifying at least one of the candidate cells based on the measurement report, and receiving a communication at the identified at least one candidate cell based on the command and the configuration of the identified candidate cell. The configuration message and command are transmitted from a base station to a user equipment ("UE"), where the base station receives the measurement report and communication from the UE. The command is layer 1 or layer 2 ("L1 / L2") signaling, and the communication received at the identified candidate cell is L1 / L2 signaling, where the L1 signaling includes at least one of downlink control information ("DCI"), uplink control information ("UCI"), and physical layer acknowledgement ("ACK") signaling, and further, the L2 signaling includes a medium access control element ("MAC CE"). The command includes cell ID information of the identified candidate cell, which is the cell to be activated. The cell ID information includes at least one of a candidate cell configuration index, a serving cell ID, a physical cell identity ("PCI"), a PCI and frequency, a reference signal ("RS") ID associated with the candidate cell, or a transmission configuration indicator ("TCI") state ID associated with the candidate cell. The candidate cells include separate lists for either candidate cells configured as special cells ("SpCells") or candidate cells configured as secondary cells ("SCells"), and identification is based on the separate lists.The candidate cells include a list of cells each of which can be configured as a special cell ("SpCell") or a secondary cell ("SCell"). The candidate cells include a list of cells each of which can be configured as a candidate cell for both a special cell ("SpCell") and a secondary cell ("SCell"). The command includes at least one of: a timing advance ("TA") value or a compensation TA value of the identified candidate cell; a cell Radio Network Temporary Identifier ("C-RNTI") of the identified candidate cell; an activation DL / UL bandwidth part ("BWP") ID of the identified candidate cell; an initial TCI state of the identified candidate cell; a serving cell ID of the identified candidate cell; an indication indicating whether the RACH procedure to the identified candidate cell is skipped; an indication indicating whether the UE maintains a connection with the current serving cell; an indication indicating whether the identified candidate cell is activated as an SpCell; and an indication indicating whether PDCP overlap is activated after accessing the identified candidate cell.

[0008] The method further includes transmitting a message to the UE including at least one of an indicator to remove all stored candidate cell configurations or a plurality of candidate cells to be removed. The UE removes the stored candidate cell configurations based on the indicator or the indicated plurality of candidate cells to be removed. The message is at least one of a handover command, a primary secondary cell ("PSCell") addition or / modification command, or a message ordering a release of a radio resource control ("RRC") connection or a suspension of an RRC connection. The method further includes transmitting a message to the UE to resume a suspended RRC connection, where the message includes at least one of a candidate cell to be resumed, activated, maintained, or restored. The candidate cell refers to a candidate cell group, where the candidate cell group is at least one of a candidate master cell group ("MCG") or a candidate secondary cell group ("SCG").

[0009] In another embodiment, a wireless communication method includes receiving a configuration message including a plurality of candidate cells having a configuration, cell identification ("ID") information, and one or more performance conditions, evaluating the performance conditions for the candidate cells to identify at least one of the candidate cells, and transmitting a communication to the identified at least one candidate cell based on the configuration of the candidate cell from a user equipment ("UE") to a base station, where the UE receives the configuration message from the base station and the UE evaluates the performance conditions. The communication to the identified at least one candidate cell is layer 1 or layer 2 ("L1 / L2") signaling, where the L1 signaling includes at least one of downlink control information ("DCI"), uplink control information ("UCI"), and physical layer acknowledgement ("ACK") signaling, and further where the L2 signaling includes a medium access control element ("MAC CE"). The evaluation includes comparing the measurement results of the candidate cells with an execution condition, where the identified at least one candidate cell satisfies the execution condition. The execution condition includes at least one of a list of measurement configuration identifier information indicating the execution condition, a measurement event based on L1 measurements for the candidate cell, or a measurement event based on L3 measurements for the candidate cell. The configuration message includes at least one of information indicating that multiple candidate cells can be identified together, or at least one execution condition for identifying multiple candidate cells together. The communication includes cell ID information of the identified at least one candidate cell, or information indicating which of the candidate cells have already been identified together.The cell ID information includes at least one of a candidate cell configuration index, a serving cell ID, a physical cell identity ("PCI"), a PCI and frequency, a reference signal ("RS") ID associated with the candidate cell, or a transmission configuration indicator ("TCI") state ID associated with the candidate cell. Transmitting communication to the identified at least one candidate cell is based on a condition including at least one of an out-of-sync indication from a serving cell or a special cell ("SpCell"), or a failure of the serving cell or the SpCell. The candidate cells include separate lists for any of the candidate cells to be configured as a special cell ("SpCell") and any of the candidate cells to be configured as a secondary cell ("SCell"), and the identification is based on the separate lists. The candidate cells include a list in which each of the candidate cells can be configured as a special cell ("SpCell") or a secondary cell ("SCell"). The candidate cells include a list, each of which can be configured as a candidate cell for both a special cell ("SpCell") and a secondary cell ("SCell").

[0010] The method further includes activating a stored cell configuration of the identified at least one candidate cell, applying a stored cell configuration of the identified at least one candidate cell, or performing mobility from a current serving cell to the identified at least one candidate cell. The method further includes starting a timer for activation or mobility, the timer being a media access control ("MAC") layer timer or a radio resource control ("RRC") layer timer. The timer is stopped based on at least one of the following conditions: successful transmission of a communication to the identified at least one candidate cell, a failure of a current serving cell, or information from a higher layer indicating a timer stop. The method further includes determining a failure for the activation or mobility based on an expiration of the timer. The method further includes reporting a failure of the activation or the mobility to the base station, the failure being reported via MAC CE or RRC signaling, notifying a higher layer of the failure of the activation or the mobility, or selecting another cell from among the stored candidate cells and performing another activation of the selected another cell or another mobility to the selected another cell. The method further includes activating the identified at least one candidate cell, where a serving cell identity is set to zero if the identified at least one candidate cell is activated as a primary cell ("PCell"), and where the serving cell identity is set based on a received identity for the identified at least one candidate cell if the identified at least one candidate cell is activated as a secondary cell ("SCell") or a primary secondary cell ("PSCell"). The method further includes receiving a message from the base station, and removing a stored candidate cell configuration based on receiving the message.The method further includes receiving a message from a base station including at least one of an indicator to remove all stored candidate cell configurations or a plurality of candidate cells to be removed, and removing the stored candidate cell configurations based on the indicator or the indicated candidate cell to be removed, the message being at least one of a handover command, a primary secondary cell ("PSCell") addition or / modification command, or a message ordering a release of a radio resource control ("RRC") connection or a suspension of an RRC connection. The method further includes receiving a message from the base station to resume a suspended RRC connection, the message including at least one of a candidate cell to be resumed, activated, maintained, or restored. The candidate cells include a candidate cell group that is at least one of a candidate master cell group ("MCG") or a candidate secondary cell group ("SCG").

[0011] In another embodiment, a wireless communication method includes transmitting a configuration message including a plurality of candidate cells having a configuration, cell identification ("ID") information, and one or more execution conditions, and receiving a communication at an identified one of the candidate cells, the candidate cell being identified based on an evaluation of the candidate cells and their configurations. The configuration message is transmitted from a base station to a user equipment ("UE"), and the communication is received from the UE at the identified candidate cell of the base station. The communication is layer 1 or layer 2 ("L1 / L2") signaling, where the L1 signaling includes at least one of downlink control information ("DCI"), uplink control information ("UCI"), and physical layer acknowledgement ("ACK") signaling, and further, the L2 signaling includes a medium access control element ("MAC CE"). Receiving the communication at the identified candidate cell is based on a condition including at least one of the following: the identified candidate cell fulfilling a trigger condition, an event triggered from an out-of-sync indication from a serving cell or special cell ("SpCell"), or a failure of the serving cell or SpCell. The execution condition includes at least one of a list of measurement configuration identifier information indicating the execution condition, a measurement event based on L1 measurements on the candidate cell, or a measurement event based on L3 measurements on the candidate cell. The configuration message includes at least one of information indicating that multiple candidate cells can be identified together, or an execution condition for identifying multiple candidate cells together. The communication includes cell ID information of the identified candidate cell, or information indicating that multiple candidate cells have already been identified together.The cell ID information includes at least one of a candidate cell configuration index, a serving cell ID, a physical cell identity ("PCI"), a PCI and frequency, a reference signal ("RS") ID associated with the candidate cell, or a transmission configuration indicator ("TCI") state ID associated with the candidate cell. The candidate cells include separate lists for any of the candidate cells to be configured as a special cell ("SpCell") or any of the candidate cells to be configured as a secondary cell ("SCell"), and the identification is based on the separate lists. The candidate cells include a list in which each of the cells can be configured as a candidate special cell (SpCell) or a candidate secondary cell (SCell). The candidate cells include a list in which each of the candidate cells can be configured as a candidate cell for both a special cell (SpCell) and a secondary cell (SCell).

[0012] The method further includes sending a message to the UE including at least one of an indicator to remove all stored candidate cell configurations or a list of candidate cells to be removed, and the UE removes the stored candidate cell configurations based on the indicator or the indicated list of candidate cells to be removed. The message is at least one of a handover command, a primary secondary cell ("PSCell") addition or / modification command, or a message ordering a release of an RRC connection or a suspension of an RRC connection. The method further includes sending a message to the UE to resume a suspended RRC connection, where the message includes one or a list of candidate cells to be resumed, activated, maintained, or restored. A candidate cell refers to a candidate cell group, where the candidate cell group is at least one of a candidate master cell group ("MCG") or a candidate secondary cell group ("SCG").

[0013] In another embodiment, a wireless communication method includes sending a request message including a plurality of candidate cells from a centralized unit ("CU") to a distributed unit ("DU") to request the DU to configure at least one of the candidate cells for mobility based on Layer 1 or Layer 2 ("L1 / L2") signaling ("L1 / L2 mobility"), and receiving a response message from the DU at the CU including a list of candidate cells that are used to identify at least one of the candidate cells already configured and a configuration for each of the candidate cells. The request message includes at least one of an indication that the procedure is initiated for L1 / L2 mobility or an indication that the procedure is initiated for a type of L1 / L2 mobility. The type of L1 / L2 mobility includes at least one of network ("NW") triggered mobility, CU triggered mobility, DU triggered mobility, or user equipment ("UE") triggered mobility.

[0014] The method further includes transmitting one or more trigger events from the CU to the DU, the trigger events enabling the DU to trigger the L1 / L2 mobility. The method further includes receiving, at the CU, one or more trigger events enabling the CU to trigger the L1 / L2 mobility from the DU. The method further includes transmitting, from the CU to the DU, a configuration message for the L1 / L2 mobility to be transmitted to the UE, the configuration message including at least one of the list of candidate cells, the identified at least one of the candidate cells, a configuration for each of the candidate cells, or one or more execution conditions for each of the candidate cells, and receiving, from the UE, via the DU, a confirmation of the configuration message. The method further includes transmitting, from the CU to the DU, at least one of the candidate cells to request the DU to activate the candidate cell via the L1 / L2 mobility. The DU sends L1 / L2 signaling to the UE to indicate at least one of the candidate cells to be activated via the L1 / L2 mobility.

[0015] The method further includes receiving at least one of the candidate cells at the CU from the DU to identify the at least one of the candidate cells that has already been successfully activated via the L1 / L2 mobility. The DU receives L1 / L2 signaling from the UE to identify that at least one of the candidate cells has already been successfully activated via L1 / L2 mobility. The method further includes sending an instruction from the CU to the DU to indicate the DU to stop transmitting L1 / L2 signaling for triggering the L1 / L2 mobility. The method further includes sending an instruction from the CU to the DU to indicate the DU to restart transmitting L1 / L2 signaling for triggering the L1 / L2 mobility. The CU and DU are parts of a base station for communicating with a user equipment ("UE"), and further, the L1 / L2 signaling is communicated with the UE. The CU provides higher layer support including PDCP and RRC layers, and the DU provides lower layer support including RLC, MAC and physical layers, and one or more DUs are configured to link with one shared CU.

[0016] In another embodiment, a wireless communication method includes receiving a request message at a distributed unit ("DU") from a centralized unit ("CU") including a plurality of candidate cells to request the DU to configure at least one of the candidate cells for mobility based on Layer 1 or Layer 2 ("L1 / L2") signaling ("L1 / L2 mobility"), and transmitting a response message from the DU to the CU including a list of candidate cells used to identify at least one of the candidate cells already configured and a configuration for each of the candidate cells. The request message includes at least one of an indication that a procedure is initiated for L1 / L2 mobility or an indication that a procedure is initiated for a type of L1 / L2 mobility. The type of L1 / L2 mobility includes at least one of network ("NW") triggered mobility, CU triggered mobility, DU triggered mobility, or user equipment ("UE") triggered mobility.

[0017] The method further includes receiving, at the DU, from the CU, one or more trigger events that the DU can trigger the L1 / L2 mobility. The method further includes transmitting, from the DU to the CU, one or more trigger events that the CU can trigger the L1 / L2 mobility. The method further includes receiving, at the DU, from the CU, a configuration message for the L1 / L2 mobility, the configuration message including at least one of the list of candidate cells, the identified at least one of the candidate cells, a configuration for each of the candidate cells, or one or more execution conditions for each of the candidate cells, transmitting the configuration message for L1 / L2 mobility from the DU to the UE, receiving, at the DU, a confirmation of the configuration message from the UE, and transmitting a confirmation of the configuration message from the DU to the CU. The method further includes receiving, at the DU, at least one of the candidate cells from the CU to request the DU to activate the candidate cell via the L1 / L2 mobility. The method further includes transmitting L1 / L2 signaling from the DU to the UE to indicate at least one of the candidate cells to be activated via the L1 / L2 mobility. The method further includes receiving L1 / L2 signaling at the DU from the UE to identify the at least one of the candidate cells already successfully activated via the L1 / L2 mobility. The method further includes transmitting at least one of the candidate cells from the DU to the CU to identify the at least one of the candidate cells already successfully activated via the L1 / L2 mobility. The method further includes receiving an indication from the CU at the DU that the DU should stop transmitting L1 / L2 signaling for triggering L1 / L2 mobility, and stopping the transmission of L1 / L2 signaling for triggering the L1 / L2 mobility from the DU to the UE.The method further includes receiving an indication from the CU at the DU indicating that the DU should restart transmission of L1 / L2 signaling for triggering the L1 / L2 mobility, and restarting transmission of the L1 / L2 signaling from the DU to the UE for triggering the L1 / L2 mobility. The CU and DU are parts of a base station for communicating with a user equipment ("UE"), and further, the L1 / L2 signaling is communicated with the UE. The CU provides higher layer support including PDCP and RRC layers, and the DU provides lower layer support including RLC, MAC and physical layers, and one or more DUs are configured to link with a shared CU.

[0018] In another embodiment, a wireless communication method includes receiving a configuration message including a plurality of candidate cells having a configuration for each of the candidate cells and a measurement configuration for at least one of the candidate cells, and performing measurements for the at least one candidate cell based on the measurement configuration. The method further includes receiving a command to identify at least one of the candidate cells based on the measurements, and triggering Layer 1 or Layer 2 ("L1 / L2") mobility from a current serving cell to the identified candidate cell based on the command and the configuration of the identified candidate cell. The method further includes evaluating measurements for the candidate cells to identify at least one of the candidate cells, and triggering Layer 1 or Layer 2 ("L1 / L2") mobility from a current serving cell to the identified candidate cell based on evaluating whether the measurements of the identified candidate cell satisfy an execution condition included in a configuration message for each of the candidate cells and the configuration of the identified candidate cell. Performing measurements, evaluating measurements, or triggering L1 / L2 mobility is performed in a device ("UE").

[0019] Additionally, the UE receives a configuration message or command from the base station, the measurement configuration including at least one of a Layer 1 ("L1") measurement configuration or a Layer 3 ("L3") measurement configuration for at least one of the candidate cells or the neighboring cell.

[0020] The L1 measurement configuration includes reference signal ("RS") resources for each candidate or neighbor cell. The RS resources include RS resource identity and at least one of synchronization signal block ("SSB") resources, channel state information reference signal ("CSI-RS") resources, or temporary reference signal ("TRS") resources. RS resources for candidate or neighbor cells are configured within a set of RS resources for a current serving cell or via a separate structure for listing RS resources for candidate or neighbor cells. The L1 measurement configuration includes a threshold for L1 Reference Signal Received Power ("RSRP") measurements of a serving cell to control L1 measurements for the candidate or neighbor cell. The method further includes performing, by the UE, L1 measurements for the candidate or neighbor cell when it is determined that an L1 RSRP measurement result for the serving cell becomes worse than a threshold.

[0021] The L1 measurement configuration includes a reporting configuration for triggering a measurement report based on an L1 measurement for a candidate cell or a neighboring cell, where the reporting configuration includes a reporting configuration identity and an identity report type. The measurement report type includes a type of report triggered based on a measurement reporting event, where the measurement reporting event includes a neighboring cell L1 measurement being better than a threshold, a neighboring cell L1 measurement being better than a serving cell L1 measurement plus an offset, a serving cell L1 measurement being worse than a first threshold and a neighboring cell L1 measurement being better than a second threshold, or a serving cell L1 measurement being worse than a first threshold and a neighboring cell L3 measurement being better than a second threshold. The method further includes triggering the measurement report based on comparing whether a measurement for at least one of the candidate cell or the neighboring cell satisfies at least one of the measurement reporting events. The method further includes receiving a second command identifying at least one of the at least one RS resource identity or the at least one cell identity of the candidate cell or the neighboring cell. The method further includes performing the measurement based on the identified RS resource identity or cell identity of the candidate cell or the neighboring cell, or reporting the measurement based on the identified RS resource identity or the identified RS resource of the cell identity of the candidate cell or the neighboring cell. The command or the second command is Layer 1 or Layer 2 ("L1 / L2") signaling, where L1 signaling includes Downlink Control Information ("DCI") and L2 signaling includes Media Access Control Element ("MAC CE"). An L3 measurement configuration includes a list of measurement information, where the measurement information includes a candidate cell identity or a cell-based offset based on an L3 measurement threshold for the candidate cell. The L3 measurement configuration includes a list of measurement information including at least one of a candidate cell identity, a list of frequency information, or a list of measurement target information. The frequency information includes at least one of a frequency or a frequency-based offset based on the L3 measurement threshold for the candidate cell.wherein the measurement object information includes at least one of: measurement object identity, or a measurement object based offset based on the L3 measurement threshold for the candidate cell. The method further includes applying the L3 measurement configuration associated with the identified candidate cell based on triggering L1 / L2 mobility to the identified candidate cell.

[0022] In another embodiment, a wireless communication method includes transmitting a configuration message including a plurality of candidate cells having a configuration for each and a measurement configuration for at least one of the candidate cells, and receiving a measurement report for the at least one candidate cell based on the measurement configuration. The method further includes transmitting a command identifying at least one of the candidate cells based on the measurement report, where the command is configured to trigger a layer 1 or layer 2 ("L1 / L2") mobility from a current serving cell to the identified candidate cell based on the command and the configuration of the identified candidate cell. The transmitting of the configuration message and the command is from a base station to a user equipment ("UE"), and the base station receives the measurement report from the UE. The measurement configuration includes at least one of a layer 1 ("L1") measurement configuration or a layer 3 ("L3") measurement configuration for at least one of the candidate cells or a neighboring cell. The method further includes an RS resource identification and at least one of a synchronization signal block ("SSB") resource, a channel state information reference signal ("CSI-RS") resource, or a temporary reference signal ("TRS") resource. The RS resources for the candidate or neighboring cell are configured within a set of RS resources for the current serving cell, or via a separate structure for listing RS resources for the candidate or neighboring cell. The L1 measurement configuration includes a threshold for L1 Reference Signal Received Power ("RSRP") measurements of the serving cell for controlling L1 measurements for the candidate or neighboring cell. The L1 measurement configuration includes a reporting configuration for triggering measurement reports based on the L1 measurements for the candidate or neighboring cell. The reporting configuration includes a reporting configuration identification and an identified report type.

[0023] The measurement report type includes a type of report triggered based on a measurement report event, which includes a neighbor cell L1 measurement becoming better than a threshold, a neighbor cell L1 measurement becoming better than a serving cell L1 measurement plus an offset, a serving cell L1 measurement becoming worse than a first threshold and a neighbor cell L1 measurement becoming better than a second threshold, or a serving cell L1 measurement becoming worse than the first threshold and a neighbor cell L3 measurement becoming better than the second threshold. The method further includes transmitting a second command identifying at least one of the at least one RS resource identity or the at least one cell identity of the candidate cell or the neighbor cell. The method further includes receiving the measurement based on the identified RS resource identity or an identified RS resource of the identified cell identity of the candidate cell or the neighbor cell. The command or the second command is Layer 1 or Layer 2 ("L1 / L2") signaling, where L1 signaling includes Downlink Control Information ("DCI") and L2 signaling includes Media Access Control Element ("MAC CE"). The L3 measurement configuration includes a list of measurement information, where the measurement information includes a candidate cell identity or a cell-based offset based on an L3 measurement threshold for the candidate cell. The L3 measurement configuration includes a list of measurement information including at least one of a candidate cell identity, a list of frequency information, or a list of measurement object information. The frequency information includes at least one of a frequency, or a frequency-based offset based on the L3 measurement threshold for the candidate cell. Wherein the measurement object information includes at least one of a measurement object identity, or a measurement object-based offset based on the L3 measurement threshold for the candidate cell.

[0024] In one embodiment, a wireless communication device comprises a processor and a memory, the processor configured to read code from the memory and implement any of the embodiments described above.

[0025] In one embodiment, a computer program product includes a computer readable program medium having stored thereon code which, when executed by a processor, causes the processor to implement any of the embodiments described above.

[0026] In some embodiments, there is a wireless communication device comprising a processor and a memory, the processor configured to read code from the memory and implement any of the methods described in any of the embodiments. In some embodiments, a computer program product includes a computer readable program medium having code stored thereon, the code, when executed by a processor, causing the processor to implement any of the methods described in any of the embodiments. These and other aspects and their implementations are described in more detail in the drawings, specification and claims. [Brief description of the drawings]

[0027] [Figure 1] FIG. 2 illustrates an exemplary base station. [Diagram 2] FIG. 1 illustrates an example random access (RA) messaging environment. [Diagram 3] FIG. 1 is a diagram showing a network architecture of a base station centralized unit (CU) and a base station distributed unit (DU). [Figure 4] A diagram showing an embodiment of intra-DU mobility of a user equipment (UE). [Diagram 5] A diagram showing an embodiment of intra-DU and inter-DU mobility of a user equipment (UE). [Figure 6] FIG. 1 illustrates an embodiment of inter-CU mobility of a user equipment (UE). [Figure 7] FIG. 1 illustrates an embodiment of network triggered inter-cell mobility. [Figure 8] FIG. 1 illustrates an embodiment of user equipment (UE) triggered inter-cell mobility. [Figure 9]A diagram showing an embodiment of intra-DU mobility based on candidate cell preparation initiated by a CU. [Figure 10] A diagram showing an embodiment of intra-DU mobility based on candidate cell preparation initiated by the DU. [Figure 11] A diagram showing an embodiment of inter-DU mobility based on candidate cell preparation initiated by a CU. [Figure 12] A diagram showing an embodiment of inter-DU mobility based on candidate cell preparation initiated by the DU. [Figure 13] A diagram showing an embodiment of intra-DU mobility based on a decision triggered by a CU. [Figure 14] A diagram showing an embodiment of intra-DU mobility based on a decision triggered by a DU. [Figure 15] A diagram showing an embodiment of intra-DU mobility based on a decision triggered by a UE. [Figure 16] FIG. 1 illustrates an embodiment of inter-DU mobility based on a decision triggered by a CU. [Figure 17] A diagram showing an embodiment of inter-DU mobility based on a decision triggered by a DU. [Figure 18] FIG. 1 illustrates an embodiment of inter-DU mobility based on a UE triggered decision. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] The present disclosure will now be described in detail with reference to the accompanying drawings, which form a part hereof, and which show, by way of illustration, specific embodiments of the present disclosure, and which illustrate, by way of illustration, the subject matter covered or claimed may be embodied in various different forms, and it is intended that the subject matter covered or claimed be not construed as being limited to any of the embodiments set forth below.

[0029] Throughout the specification and claims, terms may have subtle meanings suggested or implied by the context beyond the explicitly stated meaning. Similarly, the phrases "in one embodiment" or "in some embodiments" as used herein do not necessarily refer to the same embodiment, and "in another embodiment" or "in other embodiments" as used herein do not necessarily refer to different embodiments. The phrases "in one implementation" or "in some implementations" as used herein do not necessarily refer to the same implementation, and the phrases "in another implementation" or "in other implementations" as used herein do not necessarily refer to different implementations. For example, the claimed subject matter is intended to include combinations of all or part of the example embodiments or implementations.

[0030] Generally, a term can be understood, at least in part, from its use in context. For example, the terms "and," "or," or "and / or" as used herein may include various meanings that depend, at least in part, on the context in which such terms are used. Typically, when used to relate a list such as A, B, or C, "or" can mean A, B, and C (used herein in an inclusive sense) or A, B, or C (used herein in an exclusive sense). Also, the terms "one or more" or "at least one," as used herein, may be used to describe any feature, structure, or characteristic in a singular sense or may be used to describe a combination of features, structures, or characteristics in a plural sense, at least in part, depending on the context. Similarly, the terms "one," "one," "the," and the like, may be understood to convey a singular usage or to convey a plural usage, at least in part, depending on the context. It should also be understood that the terms "based on" or "determined by" are not necessarily intended to convey an exclusive set of factors, but instead may allow for the existence of additional factors not necessarily explicitly recited, which may also depend, at least in part, on the context.

[0031] Radio Resource Control ("RRC") is a protocol layer between the UE and the base station at the IP level (network layer). There can be various Radio Resource Control (RRC) states, such as RRC_CONNECTED, RRC_INACTIVE, and RRC_IDLE states. RRC messages are transmitted via the Packet Data Convergence Protocol ("PDCP"). As described, the UE can transmit data via a Random Access Channel ("RACH") protocol method or a Configured Grant ("CG") method. The CG can be used to reduce waste of periodically allocated resources by allowing multiple devices to share the periodic resources. The base station or node may allocate CG resources to eliminate packet transmission delays and increase utilization of the allocated periodic radio resources. The CG method is just one example of a protocol method for communication, and other examples are possible, including but not limited to RACH. The wireless communication described herein may occur via wireless access.

[0032] As described below with respect to FIGS. 1-6, a network provider may include multiple network nodes (i.e., base stations) for providing network access to user equipment ("UE") devices. The network nodes are referred to as base stations in some embodiments. FIGS. 4-6 illustrate cell mobility, in which a UE device moves between cells. To facilitate this mobility, control signaling may be used. The control signaling supports transmission of downlink and uplink transmission channels and may be referred to as Layer 1 and / or Layer 2 ("L1 / L2") signaling, indicating that corresponding information originates partly from the physical layer (Layer 1) and partly from the media access control (MAC) (Layer 2). Specifically, Layer 1 may include the physical layer, and Layer 2 may include MAC, RLC, and PDCP. L1 / L2 mobility based on L1 / L2 signaling may have lower latency, lower overhead, and reduced disruption time.

[0033] There may be a master node ("MN") and one or more secondary nodes ("SN"). The MN may include a master cell group ("MCG") and the SN may include a secondary cell group ("SCG"). The MCG is a group of cells served by the master node ("MN") and the SCG is a group of cells served by the secondary node ("SN"). The MCG may include a primary cell ("PCell") and one or more secondary cells ("SCell"). The SCG may include a primary secondary cell ("PSCell") and one or more secondary cells ("SCell"). Each primary cell may be connected to multiple secondary cells. The primary cell (PCell, PSCell) is the master cell of the respective group (MCG, SCG respectively) and may initiate the initial access. The primary cell may be used for signaling and may be referred to as a special cell ("spCell"), where spCell=PCell+PSCell. The inter-cell mobility described in these embodiments may be based on a PCell, a PSCell and / or a SCell.

[0034] A user equipment ("UE") device may move between nodes or cells. In this case, handover or change / add operations may occur to improve network reliability for the UE during the move. The move may be from a source cell to a target cell based on multiple potential target cells, called candidates. Movement between cells may also include multiple target cells that are potential candidate cells. Below, conditional handover ("CHO") and conditional PSCell addition / change ("CPAC") are described. CPAC may include conditional PSCell change ("CPC") and / or conditional PSCell addition ("CPA").

[0035] A conditional handover ("CHO") can reduce handover interruption time and improve mobility reliability. CHO is a handover executed by the UE if one or more execution conditions are met. The UE can evaluate the execution conditions when it receives a CHO configuration and can stop evaluating the execution conditions when a handover is triggered. The CHO configuration may include a candidate PCell configuration generated by a candidate target node and the corresponding execution conditions for the candidate cell.

[0036] A conditional PSCell addition / change ("CPAC") may include a UE having a network configuration to initiate access to a candidate PSCell to consider whether the PSCell is suitable for SN change, including SN addition or intra-SN change. The consideration may be based on configured conditions. A UE in a wireless network may operate under dual connectivity ("DC"), including intra-E-UTRA DC or Multi-Radio DC ("MR-DC"). In an example of intra-E-UTRA DC, both the MN and the SN provide E-UTRA access. In an example of MR-DC, one node may provide New Radio ("NR") access and another node may provide E-UTRA or NR access.

[0037] FIG. 1 illustrates an exemplary base station 102. The base station may also be referred to as a radio network node and may be a network node (e.g., a master node ("MN"), a secondary node ("SN"), and a source / target node) as illustrated in FIGS. 3A-7B. The base station 102 may be further identified as a Node B (NB, e.g., eNB or gNB) in the context of mobile communications. The exemplary base station may include wireless Tx / Rx circuitry 113 for transmitting and receiving to and from a user equipment (UE) 104. The base station may include network interface circuitry 116, e.g., optical or wired interconnects, Ethernet, and / or other data transmission media / protocols, to couple the base station to a core network 110.

[0038] The base station may also include system circuitry 122. The system circuitry 122 may include a processor 124 and / or a memory 126. The memory 126 may include operations 128 and control parameters 130. The operations 128 may include instructions for execution on one or more of the processors 124 to support the functionality of the base station. For example, the operations may handle random access transmission requests from multiple UEs. The control parameters 130 may include parameters and may support the execution of the operations 128. For example, the control parameters may include network protocol settings, random access messaging format rules, bandwidth parameters, radio frequency mapping allocations, and / or other parameters.

[0039] 2 illustrates an example random access messaging environment 200. In the random access messaging environment, a UE 104 may communicate with a base station 102 over a random access channel 252. In this example, the UE 104 supports one or more Subscriber Identity Modules (SIMs), such as SIM1 202. An electrical and physical interface 206 connects SIM1 202 to the rest of the user equipment hardware, such as via a system bus 210.

[0040] Mobile device 200 includes a communications interface 212, a system logic 214, and a user interface 218. System logic 214 may include any combination of hardware, software, firmware, or other logic. System logic 214 may be implemented using, for example, one or more systems on a chip (SoC), application specific integrated circuits (ASICs), discrete analog and digital circuits, and other circuits. System logic 214 is part of the implementation of any desired functionality within UE 104. In this regard, system logic 214 may include logic to facilitate, for example, MP3, MP4, MPEG, AVI, FLAC, AC3, etc., music and video decoding and playback or WAV decoding and playback, application execution, acceptance of user input, storage and retrieval of application data, establishment, maintenance, and termination of cellular telephone calls or data connections, such as Internet connections, establishment, maintenance, and termination of wireless network connections, Bluetooth connections, or other connections, and displaying related information on user interface 218. User interface 218 and input 228 may include graphical user interfaces, touch-sensitive displays, haptic feedback or other tactile output, voice or facial recognition input, buttons, switches, speakers, and other user interface elements. Additional examples of input 228 include microphones, video and still camera, temperature sensors, vibration sensors, rotation and orientation sensors, headset and microphone input and output jacks, Universal Serial Bus (USB) connectors, memory card slots, radiation sensors (e.g., IR sensors), and other types of inputs.

[0041] The system logic 214 may include one or more processors 216 and a memory 220. The memory 220 stores, for example, control instructions 222 for the processor 216 to execute to perform desired functions for the UE 104. Control parameters 224 provide and define configuration and operation options for the control instructions 222. The memory 220 may store BT, WiFi, 3G, 4G, 5G, or other data 226 that the UE 104 transmits or has already received via the communication interface 212. In various implementations, system power may be provided by a power storage device, such as a battery 282.

[0042] In the communications interface 212, radio frequency (RF) transmit (Tx) and receive (Rx) circuitry 230 handles the transmission and reception of signals via one or more antennas 232. The communications interface 212 may include one or more transceivers. The transceivers may be wireless transceivers that include modulation / demodulation circuitry, digital to analog converters (DACs), shaping tables, analog to digital converters (ADCs), filters, wave shapers, filters, preamplifiers, power amplifiers, and / or other logic for transmitting and receiving via one or more antennas or (in the case of some devices) over a physical (e.g., wired) medium.

[0043] The transmitted and received signals may conform to any of a wide variety of formats, protocols, modulations (e.g., QPSK, 16-QAM, 64-QAM, or 256-QAM), frequency channels, bit rates, and encoding. As one specific example, the communication interface 212 may include a transceiver supporting transmission and reception under the 2G, 3G, BT, WiFi, Universal Mobile Telecommunications System (UMTS), High Speed ​​Packet Access (HSPA)+, and 4G / Long Term Evolution (LTE) standards. However, the techniques described below are also applicable to other wireless communication technologies, whether they are produced by the 3rd Generation Partnership Project (3GPP), GSM Association, 3GPP2, IEEE, or other partnerships or standards bodies.

[0044] Multiple RAN nodes (e.g., eNB, gNB) of the same or different radio access technology ("RAT") may be deployed in the same or different frequency carriers in a particular geographical area, and they may interact via dual connectivity operations to provide joint communication services to the same target UE. A multi-RAT dual connectivity ("MR-DC") architecture may have non-quasi-colocated master nodes ("MN") and secondary nodes ("SN"). The Access Mobility Function ("AMF") and Session Management Function ("SMF") may be control plane entities, and the User Plane Function ("UPF") is a user plane entity in New Radio ("NR") or 5GC. The signaling connection between the AMF / SMF and the Master Node ("MN") may be a Next Generation-Control Plane ("NG-C") / MN interface. The signaling connection between the MN and the SN may be an Xn-Control Plane ("Xn-C") interface. The signaling connection between the MN and the UE is a Uu-Control Plane ("Uu-C") RRC interface. All these connections manage the configuration and operation of the MR-DC. The user plane connection between the User Plane Function ("UPF") and the MN may be an NG-U(MN) interface instance.

[0045] FIG. 3 illustrates a network architecture of a base station centralized unit (CU) and a base station distributed unit (DU). FIG. 3 illustrates a base station (denoted as "gNB") in communication with an overall network (denoted as "5GC"). The base stations can communicate with each other via a control plane interface ("Xn-C"). One base station is shown as having one CU connected to two DUs via an F1 interface. This is only one example of a base station arrangement. In some embodiments, there may be one or any number of DUs connected to a single CU.

[0046] A base station may be divided into two physical entities named a centralized unit ("CU") and a distributed unit ("DU"). In general, the CU may provide support for the higher layers of the protocol stack, e.g., SDAP, PDCP, and RRC, and the DU may provide support for the lower layers of the protocol stack, e.g., RLC, MAC, and physical layers. The CU may include operations for user data transmission, mobility control, radio access network sharing, session management, etc., other than the functions dedicated to the DU. The DU is a logical node having a subset of base station functions and may be controlled by the CU.

[0047] A CU may be a logical node hosting the RRC, SDAP and PDCP protocols of a base station, or the RRC and PDCP protocols of a base station, controlling the operation of one or more DUs. A DU may be a logical node hosting the RLC, MAC and PHY layers of a base station, the operation of which may be at least partially controlled by a CU. A single DU may support one or more cells. However, each cell is only supported by a single DU. Each base station may support multiple cells. As described in the embodiments herein, cell mobility between cells may be from different CUs or DUs, or may be internal to a CU and / or DU.

[0048] L1 / L2 Mobility

[0049] Inter-cell mobility based on L1 / L2 described herein may occur in several different examples. For L1 / L2 mobility, there may be intra-DU mobility where a UE changes cells within a single DU. Examples of intra-DU mobility include 1) PCell change within one DU (which may include PCell change with SCell change), 2) PSCell change within one DU (which may also include PSCell change with SCell change), and 3) PCell change within one DU (which may include SCell change within one cell group) with PSCell change within one DU. In another L1 / L2 mobility embodiment, there may be intra-CU and inter-DU mobility where a UE changes cells between different DUs but within a single CU. Examples of intra-CU and inter-DU mobility include 1) PCell change across DUs but within one CU (which may include PCell change with SCell change), and 2) PSCell change across DUs but within one CU (which may include PSCell change with SCell change). In another L1 / L2 mobility embodiment, there may be inter-CU mobility where a UE changes cells between different CUs. Examples of inter-CU mobility include 1) PCell change across CUs (which may include PCell change with SCell change), and 2) PSCell change across CUs (which may include PSCell change with SCell change). In another embodiment, there may be SCell change / addition, which may include SCell addition / change within one cell group. Figures 4 to 6 show an embodiment of UE mobility between cells.

[0050] FIG. 4 illustrates an embodiment of intra-DU mobility of a user equipment (UE). A base station may include a CU and at least one DU. In this embodiment, a single DU with multiple cells is illustrated. Cell 1 and cell 2 are both from a single DU. In this example, a UE 402 may move from cell 1 to cell 2, and the UE trajectory from cell 1 to cell 2 is illustrated in FIG. 4. Mobility from a cell may occur when the UE 402 is in a position between two cells and heading to a third position in cell 2. This is intra-DU mobility because the UE is moving between cells within a single DU.

[0051] FIG. 5 illustrates an embodiment of intra-DU and inter-DU mobility of user equipment (UE). In this embodiment, a base station may include a CU and two DUs (DU_1 and DU_2). Although each DU may have multiple cells, in this example, each DU is shown to provide one cell, such that DU_1 provides cell 1 and DU_2 provides cell 2. In this example, UE 502 may move from cell 1 to cell 2, and the UE trajectory from cell 1 to cell 2 is shown in FIG. 5, which also causes a transition from DU_1 to DU_2. Mobility from a cell may occur when UE 402 is in a position between two cells and heading to a third position in cell 2. This is intra-CU mobility because the UE is moving between cells in a single CU. However, this is also inter-DU mobility because the UE is moving between different DUs.

[0052] FIG. 6 illustrates an embodiment of inter-CU mobility of a user equipment (UE). In this embodiment, a base station may include multiple CUs (CU_1 and CU_2). Although each CU may include multiple DUs, in this example, each CU is shown to have one corresponding DU (CU_1 has DU_1, and CU_2 has DU_2). Each of the DUs is shown to have multiple cells. In this example, the UE trajectory of UE 602 passes through Cell_2 to Cell_3, inter-CU location 604 (between CU_1 and CU_2), CU_5, and Cell_6. As the UE moves, the mobility may change cells as shown, or may transition between multiple cells. Because UE 602 (at inter-CU location 604) switches cells from CU_1 to CU_2, this transition is referred to as inter-CU mobility.

[0053] Network-triggered L1 / L2 mobility

[0054] Mobility between cells can be triggered by the network (e.g., base station) or by the UE. As described, L1 / L2 signaling is used for improved mobility between cells. The examples described throughout may be triggered by the network or by the UE, and the embodiments shown in Figures 7-8 are applicable to other embodiments.

[0055] FIG. 7 illustrates an embodiment of network-triggered inter-cell mobility. This embodiment illustrates communication or signaling between the UE, the source cell, and the target cell. The communication illustrates how the UE can move from the source cell to the target cell, and the L1 / L2 signaling used as part of the transition. In block 702, the network ("NW") pre-configures one or more candidate / neighboring cells for inter-cell mobility via RRC signaling (e.g., RRCReconfiguration message). The candidate cell configuration may include multiple candidates to act as the target cell. In the following, different embodiments and examples are described regarding the candidate list and what the configuration includes. In block 704, the UE responds to the RRC message with a confirmation / completion message to the network in the source cell. This message may be RRCReconfigurationComplete in one embodiment. In block 706, the UE reports L1 and / or L3 measurements on neighboring cells (i.e., potential candidate cells) to the network. Further embodiments and examples regarding measurements and neighbors / candidates are described below.

[0056] In one embodiment, in block 708, the source cell of the network determines at least one of the candidate cells to be activated based on the measurements. The candidate cell to be activated may be referred to as an identified cell or an identified candidate cell. The identification process is further described below. Based on the identification of the at least one target cell, the source cell sends a trigger command to the UE in block 710, including the identification information of the at least one target cell. The trigger command is an L1 / L2 command. Based on receiving the L1 / L2 command, the UE switches to the target cell in block 712 and communicates with the target cell in block 714. The communication between the UE and the target cell is via L1 / L2 signaling. As described, using L1 / L2 signaling for cell mobility can provide several advantages. In some embodiments, configuration details of neighbor / candidate cells (including the target cell) may be provided to identify or determine the target cell. This information may be further utilized to establish L1 / L2 communication in block 714 after identification by the UE.

[0057] UE triggered L1 / L2 mobility

[0058] Mobility between cells can be triggered by the network (e.g., base station) or by the UE. As described, L1 / L2 signaling is used for improved mobility between cells. The examples described throughout may be triggered by the network or by the UE, and the embodiments shown in Figures 7-8 are applicable to other embodiments.

[0059] FIG. 8 illustrates an embodiment of user equipment (UE) triggered inter-cell mobility. This embodiment illustrates communication or signaling between the UE, the source cell, and the target cell. The communication illustrates how the UE can move from the source cell to the target cell, and the L1 / L2 signaling used as part of the transition. In block 802, the network ("NW") pre-configures one or more candidate / neighboring cells for inter-cell mobility via RRC signaling (e.g., RRCReconfiguration message). The candidate cell configuration may include multiple candidates to act as the target cell. Furthermore, the configuration message includes trigger conditions that are also used by the UE to trigger mobility based on the configuration for the candidate cells. In the following, different embodiments and examples are described with respect to the candidate list, configuration, and trigger conditions. In block 804, the UE responds to the RRC message with a confirmation / completion message to the network in the source cell. This message may be RRCReconfigurationComplete in one embodiment.

[0060] For the UE-triggered example, the UE evaluates a trigger condition in block 806. The evaluation of the trigger condition is utilized to identify a target cell among the candidate cells in block 808. The trigger condition may be referred to as an execution condition. Specifically, if at least one candidate cell satisfies the trigger condition, the UE may switch to that candidate cell. That is, the UE may not switch to a candidate cell if the candidate cell does not satisfy the trigger condition. The identification in block 808 may also include activating or switching to the target cell, and the UE may communicate with the target cell in block 810. The communication between the UE and the target cell is via L1 / L2 signaling. As described, using L1 / L2 signaling for cell mobility may provide several advantages. In some embodiments, configuration details of neighbor / candidate cells (including the target cell) may be provided to identify or determine the target cell. This information may be further utilized to establish L1 / L2 communication in block 810 after identification by the UE.

[0061] Candidate cell setting

[0062] As described with respect to Figures 7-8, the candidate cell may include a transmitted configuration. The configuration may include configuration parameters provided to identify the candidate cell (e.g., the target cell). The candidate cell configuration may include lower layer configuration (e.g., RLC layer configuration, MAC layer configuration, and / or physical layer configuration). In some embodiments, the candidate cell configuration may include at least one of the following information elements (IEs): CellCroupConfig, SpCellConfig, ServingCellConfigCommon, and / or ServingCellConfig.

[0063] The candidate cell configurations may be provided via different options: in one embodiment, each candidate cell configuration may be included in one RRC container and associated with cell identity (ID) information (e.g., as in CHO / HO based solutions); in another embodiment, the candidate cell configurations may be included as a cell list in an RRC message and each cell configuration may be associated with cell identity information (e.g., as in cell activation / deactivation based solutions).

[0064] The cell ID information utilized for the configuration and maintenance of the candidate cell may include a candidate cell configuration index (e.g., CandReconfigId), a candidate / serving cell ID (e.g., ServCellIndex), a physical cell ID (PCI), a PCI+frequency, or a reference signal (RS) ID associated with the candidate cell (e.g., an RS ID associated with the candidate cell via a PCI that is configured as part of the current serving cell configuration). The RS may be at least one of a synchronization signal block (SSB), a channel state information (CSI) reference signal (CSI-RS), and a temporary / tracking reference signal (TRS). In other embodiments, a transmission configuration indicator (TCI) state ID associated with the candidate cell may be utilized. The TCI state may be associated with the candidate cell (e.g., via a PCI) or configured as part of the current serving cell configuration.

[0065] The stored candidate cell can be activated as an SpCell or an SCell. In some embodiments, the cell may be activated as both. In the following, examples of cases where the cell is activated as an SpCell, an SCell, or both are described.

[0066] In one embodiment for identifying candidate cells, there may be separate structures / lists for candidate SpCells (i.e., PCell, PSCell) and candidate SCells, such as a candidate SpCell list (e.g., candidateSpCellToAddModList, candidateSpCellToReleaseList) and a candidate SCell list (candidateSCellToAddModList, candidateSCellToReleaseList).

[0067] In another embodiment for identifying candidate cells, there may be a common structure / list for candidate cells (e.g., candidateCellToAddModList, candidateCellToReleaseList). Each entry may be set as either a candidate SpCell or a candidate SCell. In this example, there may be an indicator / flag (e.g., candidateCellType, candidateSpCell, or candidateSCell) that indicates whether the cell can be a candidate SpCell or a candidate SCell. In another alternative of this example, there may be different cell ID ranges that are allocated to candidate SpCells and candidate SCells (e.g., values ​​0 to X are allocated to candidate SpCells and values ​​X+1 to N are allocated to candidate SCells). In another alternative of this example, there may be a bitmap that is used to indicate which cells can be activated as SpCells (e.g., a bit in the bitmap set to 1 indicates that the cell can be activated as a SpCell). In another alternative of this example, within the candidate cell configuration, there may be SpCell-specific configurations (e.g., SpCellConfig, reconfigurationWithSync, PUCCH-Config) that can be used to distinguish whether the candidate cell can be activated as an SpCell or a SCell. For example, if the candidate cell configuration includes a SpCell-specific command, the candidate cell is used as a candidate SpCell. Otherwise, it is used as a candidate SCell.

[0068] In another embodiment for identifying candidate cells, there may be a common structure / list for candidate cells (e.g., candidateCellToAddModList, candidateCellToReleaseList). Each entry may be configured as a candidate cell for both SpCell and SCell. In an alternative embodiment of this embodiment, for example, for an entry that includes SpCell-specific configuration (e.g., SpCellConfig, reconfigurationWithSync, PUCCH-Config), the associated candidate cell may be used as both a candidate SpCell and a candidate SCell. Otherwise, this entry may be used as a candidate SCell. In another alternative embodiment of this embodiment, this entry includes two sub-entries, one sub-entry includes configurations used for candidate SpCells (e.g., including SpCell-specific configurations) and another sub-entry includes configurations used for candidate SCells (e.g., not including SpCell-specific configurations). It may be up to the network ("NW") to decide how to use a candidate cell as an SpCell or SCell.

[0069] In another embodiment, an indicator or flag in the mobility triggering L1 / L2 command may also indicate whether the cell is activated as an SpCell or not. SpCell specific configuration may be used / applied by the UE if the cell is activated as an SpCell.

[0070] In some embodiments, the NW may also provide information about which cells can be activated simultaneously. The candidate cell mapping / combination information can be provided via several different methods. In one example, there may be a cell combination list (e.g., candidateCellCombinationList) that indicates which candidate cells can be activated simultaneously. Each item in this list may include a cell combination that includes a cell combination ID (to identify any potential cell combination) and / or multiple candidate cell IDs. In another example, there may be a bitmap that indicates which candidate cells can be activated simultaneously (e.g., to indicate N candidate cells, the size of the bitmap is N bits). A bit set to 1 in the bitmap indicates that the cells can be activated simultaneously, or a bit set to 0 indicates that the cells cannot be activated simultaneously.

[0071] [Table 1]

[0072] In this example with four candidate cells preconfigured by the NW, only 1+2+3, 1+3+4, 1+2+4 are allowed to be activated at the same time. The NW can provide the above bitmap table as part of the configuration. Alternatively, the NW may provide a list of candidate cell ID combinations, e.g., {Cell_1, Cell_2, Cell_3}, {Cell_1, Cell_3, Cell_4}, {Cell_1, Cell_2, Cell_4}.

[0073] There may be various embodiments to reduce the signaling overhead for candidate cell configuration. In one embodiment, one or more individual common sets / templates are defined as a baseline for candidate cell configuration, and candidate cells are configured based on the baseline configuration and the delta configuration added to the baseline configuration. In another embodiment, one or more serving / candidate cells are identified as reference cells (e.g., including a reference ID for the current serving cell ID or another candidate cell ID) and configured candidate cells in a candidate cell configuration entry in a candidate cell list based on the reference cell configuration and the delta configuration for the reference cell configuration. In this embodiment, a serving cell may be considered to be reused as a candidate cell, or vice versa. Specifically, a reference cell indicator (e.g., referenceCell) is included in the candidate cell configuration or serving cell configuration. For example, for a candidate cell entry, a serving cell ID (e.g., SCellIndex or ServCellIndex) may be included to indicate that the referenced serving cell is also considered as a candidate cell for L1 / L2 mobility. The candidate cell ID may be indicated in the current serving cell configuration (eg, SpCellConfig or SCellConfig) to indicate that this candidate cell is to be added as a serving cell (eg, via an RRC reconfiguration message).

[0074] L1 / L3 measurements

[0075] 7 illustrates L1 / L3 measurements used for measurement reporting to help determine / distinguish a target cell from a candidate cell. In some embodiments, the L1 / L3 measurement configuration may be provided to the UE by the network.

[0076] The NW may provide the L1 measurement configuration for the candidate cell or neighbor cell to the UE via at least one of the following alternatives 1) to 3): 1) configure / add L1 measurements for the candidate cell in the current L1 measurement configuration (e.g., channel state information measurement configuration CSI-MeasConfig) on ​​the serving cell; 2) configure or reuse L1 measurements for the candidate cell in the RRM measurement configuration (e.g., MeasConfig); 3) define a separate structure for providing L1 measurements for the candidate cell; or 4) configure or include L1 measurement configuration for the candidate cell in the respective candidate cell configuration.

[0077] The L1 measurement configuration may include at least one of the following items: an addition / modification list for L1 measurement objects / resources, a removal list for L1 measurement objects / resources, an addition / modification list for L1 measurement IDs (measurement IDs are the link between measurement objects / resources and reporting configurations), a removal list for L1 measurement IDs, an addition / modification list for L1 reporting configurations, a removal list for L1 reporting configurations, a measurement gap configuration for L1 measurements, or a threshold for SpCell / serving cell RSRP measurement control (e.g., L1 SSB RSRP threshold or L1 CSI-RS RSRP threshold) if the UE is requested to perform L1 measurements for non-serving / candidate cells. If the serving cell becomes worse than the threshold, the UE may be requested to perform L1 measurements for non-serving / candidate / neighboring cells. These measurements are then used to select / identify a target cell among the candidate cells.

[0078] L1 measurements can be provided or activated in different embodiments. Measurements may be referred to as objects / resources (e.g., reference signal resources used for L1 measurements). They may be provided in the following alternatives 1)-3): 1) configure or add reference signal (RS) resources related to candidate / neighboring cells in the L1 measurement configuration (e.g., CSI-ResourceConfig) for the current serving cell; 2) reuse RS resources related to candidate / neighboring cells in the L3 / RRM measurements or configure / add additional RS resources related to candidate / neighboring cells (e.g., CSI-RS-ResourceConfigMobility) in the L3 / RRM measurement configuration; 3) define a separate structure providing RS resources for candidate / neighboring cells; or 4) configure / include RS resources for candidate cells in each candidate cell configuration. The RS type may include at least one of SSB, CSI-RS, and TRS. In some embodiments, the RS resource may include at least one of: 1) RS resource ID, 2) frequency domain resource of the RS, 3) time domain resource of the RS, or 4) resource type (e.g., aperiodic, semi-persistent, or periodic). For RS measurement resource activation to be configured, the RS / measurement resource may be considered as activated (e.g., detectable or measurable by the UE) when configured. Or, the RS / measurement resource may be considered as deactivated (e.g., not detectable or measurable by the UE) when configured. The NW may explicitly indicate (e.g., via L1 / L2 command or RRC signaling) which RS resource related to the neighbor / candidate cell should be activated (e.g., indicate RS resource ID, candidate cell ID). If the RS resource related to the neighbor / candidate cell is activated, the UE may be requested to perform L1 measurements on the RS resource related to the neighbor / candidate cell. If the RS resources related to the neighbor / candidate cell are deactivated, the UE may not be required to perform L1 measurements on the RS resources related to the neighbor / candidate cell.

[0079] L1 measurement reporting may be configured in various ways. An L1 measurement reporting configuration (e.g., CSI-ReportConfig) may be used to configure L1 measurement reporting on the current serving cell. This may include at least one of a reporting configuration ID, or a reporting type (e.g., aperiodic, semi-persistent, periodic, or event triggered). For the event triggered type, the triggering event may be established as a new event based on the L1 measurement. For example, the neighbor cell's L1 measurement becomes better than a threshold (e.g., A4 event, RSRP, RSRQ, and / or SINR values). In another example, the neighbor cell's L1 measurement becomes better than the SpCell / serving cell's L1 measurement by more than an offset (e.g., A3 event). In another example, the L1 measurement of the SpCell / serving cell becomes worse than a first threshold and the L1 measurement of the neighbor cell becomes better than a second threshold (e.g., A5 event). The L1 measurement report can be further configured by reusing the L3 based measurement event (e.g., event A3 / A4 / A5, etc.), but with additional parameter values ​​for L1 / L2 mobility (e.g., additional hysteresis, timeToTrigger, threshold). More flexible values ​​can make L1 / L2 mobility easier to trigger. The L1 measurement report can be further configured based on the L1 measurement on the serving cell and the L3 measurement on the candidate / neighbor cell due to a new event. For example, the L1 measurement of the SpCell / serving cell becomes worse than a first threshold and the L3 measurement of the neighbor cell becomes better than a second threshold (e.g., A5-like event).

[0080] The L1 measurement gap may be configured to define a window in which the UE can perform inter-frequency and / or intra-frequency L1 measurements. The measurement gap may be provided by reusing the measurement gap configuration for L3 / RRM measurements (e.g., MeasGapConfig). Additional parameter values ​​may be configured for L1 measurements (e.g., additional gapOffset, mgl, mgrp, mgta, etc.). The offset values ​​may be based on the parameter values ​​for L3 measurements (e.g., offset values ​​for gapOffset, mgl, mgrp, mgta, etc.). The L1 measurement gap may be configured to define a separate measurement gap configuration for L1 measurements (e.g., L1MeasGapConfig). The L1 measurement gap configuration may be configured to define a separate measurement gap configuration for L1 measurements (e.g., L1MeasGapConfig). The L1 measurement gap configuration may be configured to define a separate measurement gap configuration for L1 measurements (e.g., L1MeasGapConfig). ● Gap type (e.g. gap every FR1, gap every FR2, gap every UE), ● Gap offset, ● Measurement gap repetition period, ● Measurement gap length, ● Measurement gap timing advance, or ● The reference serving cell whose SFN and subframe are used for the gap calculation for this gap pattern; may include at least one of the following items.

[0081] In Fig. 8, trigger conditions are provided to the UE. The trigger conditions, also referred to as execution conditions, define conditions or thresholds under which mobility can be triggered. In one embodiment, the trigger conditions include a list of measurement identifiers measIds that may be associated with L1 / L3 measurement objects / resources and reporting configurations as described above. In another embodiment, the trigger conditions include any of the measurement events listed above.

[0082] A candidate cell may be associated with a trigger condition. Specifically, one or more execution conditions are associated with one candidate cell. In another embodiment, one or more execution conditions are associated with multiple candidate cells (e.g., one or more conditions for a candidate cell combination that includes both an SpCell and an associated SCell). When multiple conditions are associated with a candidate cell / cell combination, the UE may consider the condition to be satisfied if all conditions are satisfied (e.g., each condition relationship is "AND") or if one of the conditions is satisfied (e.g., each condition relationship is "OR").

[0083] The configured radio resource management (RRM) measurements may be affected by the execution of L1 / L2 mobility (e.g., change between inter-frequency and intra-frequency measurements). UE-side triggering events (e.g., for other candidate cells or CHOs, when coexistence with CHO is allowed) should be taken into account to ensure that the events are still valid after the execution of L1 / L2 mobility. The updated RRM measurement configurations (e.g., measurement target configuration, measurement report configuration, measurement gap configuration) may be provided in different ways in various embodiments. In one embodiment, the NW pre-configures the UE with the measurement configurations to be updated associated with each candidate cell. For example, the measurement configurations are included in each candidate cell configuration or a separate structure for measurement configuration updates is defined (e.g., a list of measurement configurations, each associated with a candidate cell ID). Upon triggering L1 / L2-based mobility, the UE applies the corresponding measurement configuration of the target cell. In another embodiment, the UE automatically triggers measurement configuration switching when L1 / L2-based mobility is triggered or upon successful completion of mobility (e.g., the measId associated with the measObjectId value corresponding to the source frequency is associated with the measObjectId value corresponding to the target frequency). In another embodiment combining the above-mentioned embodiments, the NW pre-configures the UE with a part of the measurement configuration (e.g., gap configuration, reporting configuration) associated with each candidate cell to be updated. Upon triggering L1 / L2-based mobility, the UE performs automatic mobility switching and applies the corresponding measurement configuration of the target cell based on the baseline / source measurement configuration.

[0084] For reporting configuration (e.g., including trigger / execution conditions) updates, the source configuration can be saved as a template / baseline, or the NW provides a separate set of reporting configurations as the template / baseline. For each candidate cell, the NW provides a set of delta configurations that can be applied based on the template / baseline when triggering L1 / L2 mobility. The delta configurations may include a list of cell-based offset values ​​(e.g., RSRP, RSRQ, SINR values), each associated with each candidate cell. When a candidate cell is selected / indicated to be activated / switched as a target cell, the UE adds the cell-based offset value associated with the cell to the threshold / offset value in the template / baseline configuration to generate a new reporting configuration for the target cell. An exemplary signaling configuration is shown in Table 2 below.

[0085] [Table 2]

[0086] In Table 2, the measurement information for the delta configuration includes a list of candidate cell IDs and associated cell-based offset values. The delta configuration may further include a set of frequency / MO-based offset values ​​(e.g., RSRP, RSRQ, SINR values) for each candidate cell. When a candidate cell is selected / indicated to be activated / switched as a target cell, the UE adds the frequency-based offset value associated with the cell to the threshold / offset value associated with the corresponding frequency in the template / baseline configuration. An example signaling configuration is shown in Table 3 below.

[0087] [Table 3]

[0088] In Table 3, the measurement information for delta configuration includes a list of candidate cell IDs and an associated measurement object / frequency information list. Each measurement object / frequency information includes a list of measurement object IDs or frequencies and an associated measurement object / frequency value.

[0089] To provide measurement gap configuration updates, there may be a list of measurement gap configurations (e.g., measGapConfigList) each associated with a set of candidate cells (e.g., a candidate cell list in GapConfig). In another embodiment for providing measurement gap configuration updates, there may be a list of candidate cells, each associated with one measurement gap configuration or a set of measurement gap configurations. In another embodiment for providing measurement gap configuration updates, there may be a template / baseline measurement gap configuration (e.g., a source measurement gap configuration), and the list of updated measurement configurations are delta configurations based on the template / baseline. When a candidate cell is activated, the UE autonomously applies / activates the associated measurement gap configuration.

[0090] Network-triggered for L1 / L2 mobility

[0091] Returning to FIG. 7, L1 / L2 mobility may be triggered by the network. In block 706, L1 / L3 measurements on neighboring cells (including candidate cells) are reported by the UE to the NW. The NW selects a target candidate cell based on the measurement report in block 708, and sends a trigger command (e.g., L1 / L2 command) in block 710 to instruct the UE to select the indicated cell and perform inter-cell mobility. In the following, another example of triggering L1 / L3 measurement reporting is described. When a condition / event for a configured report type (e.g., aperiodic, semi-persistent, periodic, or event-triggered) is met, the UE can trigger L1 / L3 measurement reporting. For the aperiodic type, when a DCI trigger for an L1 measurement report request is received, the UE should send an aperiodic L1 measurement report (e.g., CSI report) on the PUSCH. For the semi-persistent type, when a DCI trigger for an L1 measurement report request is received, the UE may send a semi-persistent L1 measurement report (e.g., CSI report) on the PUSCH. For the semi-persistent type, when a MAC CE for an L1 measurement report request is received, the UE should send a semi-persistent L1 measurement report (e.g., CSI report) on the PUCCH. For the periodic type, the UE should send a periodic L1 measurement report (e.g., CSI report) on the PUCCH according to a configured / defined periodicity. For the event-triggered type, when an L1 measurement that satisfies a configured condition / event is determined / detected, the UE should send an L1 measurement report (e.g., via a CSI report or MAC CE).

[0092] In an alternative embodiment, the UE may trigger an L1 / L3 measurement report upon detection of N consecutive L1 measurements that satisfy a condition (e.g., for the types triggered by the events listed above). In an alternative embodiment, the UE may trigger an L1 / L3 measurement report upon detection of N consecutive "out of sync" indications for the SpCell / serving cell from lower layers (i.e., upon detection of a physical layer problem). In an alternative embodiment, the UE may trigger an L1 / L3 measurement report upon detection of a radio link failure (RLF) or beam failure recovery (BFR) on the SpCell / serving cell, e.g., T310 expiration, T312 expiration, random access problem, maximum retransmissions reached, or listen before talk (LBT) failure.

[0093] The measurement report can be sent via L1 signaling (e.g., via CSI report) or MAC CE. The measurement report may include at least one of L1 SSB RSRP, L1 SSB RSRQ, L1 SSB SINR, L1 CSI-RS RSRP, L1 CSI-RS RSRQ, L1 CSI-RS SINR for neighbor / candidate cells or / and serving cell. The NW may also indicate (e.g., via RS resource ID, candidate cell ID) which measurements related to neighbor / candidate cells are requested to be reported, e.g., via L1 / L2 commands (Downlink Control Information (DCI), MAC Control Element (MAC CE)). The UE may send a measurement report including only the measurement results for the indicated neighbor / candidate cells.

[0094] The trigger command may be at least one of a physical layer DCI, a MAC CE, or an RRC signaling. The trigger command may include at least one of the following information of one or more selected cells to indicate that the UE activates or switches to the indicated cell: ● Candidate cell configuration index (for example, CandReconfigId). ● Candidate / serving cell ID (eg ServCellIndex). ● PCI or PCI+ frequency. ● A reference signal (RS) ID related to the candidate cell, e.g., an RS ID associated with the candidate cell (e.g., via a Physical Cell ID (PCI)) is already configured as part of the current serving cell configuration. The RS may be at least one of a synchronization signal block (SSB), a channel state information reference signal (CSI-RS), and a tracking / temporary reference signal (TRS). ● A Transmission Configuration Indicator (TCI) state ID related to the candidate cell (e.g. a TCI state associated with the candidate cell via a PCI) is already configured as part of the current serving cell configuration, or ● Candidate cell combination IDs (eg, to indicate which candidate cells can be activated simultaneously).

[0095] The trigger command also ● The Timing Advance (TA) value or compensation TA value of the selected / indicated candidate cell; ● The Cell Radio Network Temporary Identifier (C-RNTI) of the selected / indicated candidate cell; ● Activation DL / UL BWP ID of selected / indicated candidate cell; ● An indication / flag indicating whether the UE can maintain connection with the source / current SpCell / serving cell during L1 / L2 based inter-cell mobility (i.e. like DAPS HO); An indication or flag indicating whether a RACH procedure to the selected / indicated candidate cell is required / skipped or whether a RACH-less procedure is allowed; ● The initial TCI state of the selected / indicated candidate cell; ● Serving cell ID for the selected / indicated candidate cell; ● A PDCP overlap activation / deactivation indication, indicating whether PDCP overlap is activated / maintained / deactivated after completion of L1 / L2 based inter-cell mobility, or An indication or flag indicating whether the selected / indicated candidate cell has been activated as an SpCell; The information may include at least one of the following:

[0096] UE triggered for L1 / L2 mobility

[0097] Returning to FIG. 8, L1 / L2 mobility may be triggered by a user equipment (UE). In block 806, the UE starts evaluating the execution / triggering conditions for the candidate cells. If at least one candidate cell satisfies the corresponding execution condition, the UE connects to the target candidate cell in block 808 based on the stored cell configuration. L1 / L2 mobility execution may be triggered when at least one of the following conditions is met: ● If at least one candidate cell / cell combination satisfies the corresponding execution condition, ● If at least one candidate cell / cell combination satisfies the corresponding execution condition N times in a row, When N consecutive "out of sync" indications are detected from lower layers for the SpCell / serving cell (i.e. when a physical layer problem is detected), ● Upon detection of a Radio Link Failure (RLF) or Beam Failure Recovery (BFR) on the SpCell / serving cell (e.g. T310 expiry, T312 expiry, random access problem, maximum number of RLC retransmissions reached, or LBT failure).

[0098] UE behavior upon trigger

[0099] Although the above example is for the UE triggering case, the following description of UE behavior when triggering L1 / L2-based inter-cell mobility is also applicable to both UE-triggered mobility and NW-triggered mobility. When L1 / L2-based inter-cell mobility is triggered (e.g., upon receiving an L1 / L2 trigger command or detecting that an execution condition is met), the UE may perform at least one of the following operations: ● Apply / activate the memorized cell settings of the indicated / selected candidate / target cell. ● When a cell is instructed by the NW to be activated as an SpCell (e.g. via a trigger command indication), apply / activate the stored SpCell configurations (i.e. configurations including SpCell specific configurations) of the instructed / selected candidate / target cell. ● If instructed by the NW (e.g. via an instruction in a trigger command), apply new TA values ​​or apply compensation TA values ​​based on the current TA values ​​for the indicated / selected candidate / target cells. ● If instructed by the NW (eg via an indication in a trigger command), apply C-RNTI or / and Serving Cell ID for the indicated / selected candidate / target cell. ● When instructed by the NW (e.g. via an indication in a trigger command), switch / activate the Uplink (UP) / Downlink (DL) / Bandwidth Part (BWP) according to the activating DL / UL BWP Identifier (ID). Activate timers for L1 / L2 mobility (eg MAC layer timers or RRC layer timers, such as T304). Detach from the source / current SpCell / serving cell and synchronize and attach to the indicated / selected candidate / target cell, or ● If instructed by the NW (e.g. via an indication in a trigger command), maintain connection with the source / current SpCell / serving cell and synchronize and connect to an indicated / selected candidate / target cell.

[0100] For connecting to the target cell, the UE may perform the following process. In one embodiment, if RACH-less is not configured / allowed, the UE accesses the target cell via a RACH procedure (e.g., CBRA, CFRA, 2-step RA) and completes the L1 / L2-based inter-cell mobility procedure by transmitting L1 / L2 signaling to the target cell. In an alternative embodiment, if RACH-less is configured / allowed (e.g., via an indication in a trigger command), the UE transmits L1 / L2 signaling to the target cell via a pre-assigned uplink grant. In another embodiment, the UE monitors a physical downlink control channel (PDCCH) of the target cell to receive an uplink grant, and transmits L1 / L2 signaling to the target cell via the received uplink grant. In another embodiment, the UE transmits a Scheduling Request (SR) to the target cell, starts monitoring a PDCCH of the target cell to receive an uplink grant, and transmits L1 / L2 signaling to the target cell via the received uplink grant. In another embodiment, the UE monitors the PDCCH of the target cell with the indicated TCI state in the received L1 / L2 trigger command to receive an uplink grant, and the UE transmits L1 / L2 signaling to the target cell via the received uplink grant. In another embodiment, the UE transmits an SR to the target cell, starts monitoring the PDCCH of the target cell with the TCI state indicated in the received L1 / L2 trigger command to receive an uplink grant, and transmits L1 / L2 signaling to the target cell via the received uplink grant.

[0101] The L1 / L2 signaling may be at least one of a physical layer uplink control information (UCI), an ACK, or a MAC CE. The L1 / L2 signaling may also include an activation / selected candidate / target cell ID or an activation / selected candidate cell combination ID to the NW.

[0102] To switch from a current / source serving cell to a target cell, the UE performs switching between the candidate cell ID and the serving cell ID. When L1 / L2-based inter-cell mobility is triggered, the UE can automatically switch between the candidate cell ID (used for the configuration and maintenance of the candidate cell) and the serving cell ID (used for subsequent cell operations, e.g., in the SCell activation / deactivation MAC CE) if the serving cell ID is not explicitly provided by the NW (e.g., not pre-configured with the candidate cell configuration and / or not indicated in the trigger command). For each candidate cell, if the candidate cell is activated as a PCell, the UE sets the serving cell ID for that cell as 0 (i.e., ServCellIndex=0), but if the candidate cell is activated as a SCell or PSCell, the UE uses the previously allocated candidate cell ID for the candidate cell (e.g., the candidate cell ID included in the RRC message with the candidate cell configuration) as the serving cell ID (ServCellIndex=Candidate Cell ID).

[0103] Detecting / Responding to L1 / L2 Mobility Failures

[0104] A new timer may be used for L1 / L2 based inter-cell mobility (e.g., a timer like T304). The timer may be an RRC layer timer or a MAC layer timer. In one embodiment, the timer starts when triggering L1 / L2 based inter-cell mobility (e.g., upon receipt of an L1 / L2 command or upon execution of UE triggered L1 / L2 mobility (i.e., upon applying a stored candidate cell configuration or upon detection that an execution condition is met)). The timer: ● Upon successful completion of L1 / L2 based inter-cell mobility, e.g., upon successful completion of random access on the corresponding candidate cell or when sending L1 / L2 indications (e.g. UCI, ACK, MAC CE) to the corresponding candidate / target cell; Upon detection of RLF / BFR on the current / source serving cell, ● When releasing the candidate cell setting, ● If the timer is configured as a MAC layer timer, when the RRC layer notifies the MAC layer to stop the timer, ● If the timer is an RRC layer timer, when the MAC layer informs the RRC layer about the successful completion of the L1 / L2-based inter-cell mobility; It stops if at least one of the following conditions is met:

[0105] If the timer is a MAC layer timer and the timer expires, the UE may trigger / send a MAC CE to report the L1 / L2 mobility failure. In another embodiment, if the timer is a MAC layer timer and the timer expires, the UE may notify a higher layer (e.g., the RRC layer) about the detection of the L1 / L2 mobility failure. The RRC layer may then trigger an RRC re-establishment procedure and report the L1 / L2 mobility failure to the NW, or select another candidate cell from the stored candidate cells and perform a second L1 / L2 inter-cell mobility (e.g., activate or switch to another candidate cell).

[0106] If the timer is an RRC layer timer and the timer expires, the UE may trigger an RRC re-establishment procedure. In another embodiment, if the timer is an RRC layer timer and the timer expires, the UE may report an L1 / L2 mobility failure to the NW. In another embodiment, if the timer is an RRC layer timer and the timer expires, the UE may select another candidate cell among the stored candidate cells and perform a second L1 / L2 inter-cell mobility (e.g., activate or switch to another candidate cell).

[0107] The above-mentioned L1 / L2 mobility failure report can be sent to the NW via L1 / L2 signaling (e.g., UCI, MAC CE), or via RRC signaling (e.g., reusing existing RRC messages including FailureInformation message, MCGFailureInformation message, or SCGFailureInformation message), or by defining a new RRC message. The failure report may include a failure type (e.g., L1 / L2 mobility failure) and / or failed candidate cell ID or failed candidate cell combination ID information.

[0108] In one embodiment, there may be a CHO-based recovery solution. If the UE fails to access a candidate cell and detects that at least one of the other candidate cells meets the corresponding trigger condition or an individual condition / threshold set by the NW (e.g., a condition / threshold used only for cell selection during failure recovery), the UE may automatically trigger a second L1 / L2 mobility to the selected candidate cell. If the failed cell is a candidate PCell (e.g., DAPS) and the source cell connection is maintained during L1 / L2 mobility, the UE may fall back to the source cell and report an L1 / L2 mobility failure to the source cell. If the failed cell is a candidate PSCell or a candidate SCell, the UE reports the failure information to the NW via RRC signaling (e.g., FailureInformation message, or SCGFailureInformation message) or MAC CE (e.g., new failure report MAC CE).

[0109] If Packet Data Convergence Protocol (PDCP) overlap is configured for the UE, several alternatives may be considered for handling the PDCP overlap when triggering L1 / L2-based inter-cell mobility or upon completion of L1 / L2-based inter-cell mobility. In one embodiment, the UE autonomously deactivates the PDCP overlap when triggering L1 / L2 mobility. In another embodiment, the NW explicitly indicates (e.g., via an L1 / L2 mobility trigger command) whether to activate / deactivate / maintain the PDCP overlap. In another embodiment, upon execution / completion of L1 / L2 mobility, if the previous logical channel (LCH) is removed (e.g., there is no serving cell associated with the previous LCH), the UE autonomously switches the primaryPath to refer to another LCH (e.g., the LCH associated with the activated candidate cell).

[0110] CU / DU cooperation

[0111] As described above with respect to FIG. 3, a network (NW) or base station may include a centralized unit (CU) and a distributed unit (DU). In general, a CU may provide support for higher layers of a protocol stack, such as SDAP, PDCP, and RRC, and a DU may provide support for lower layers of the protocol stack, such as RLC, MAC, and physical layers. A CU may include operations for user data transmission, mobility control, radio access network sharing, session management, etc., other than the functions dedicated to the DU. A single DU may support one or multiple cells. However, each cell is only supported by a single DU. Cell mobility between cells may be from different CUs or DUs, or may be limited to within a CU and / or DU.

[0112] There are several examples as shown in Figures 4 to 6. Figure 4 shows an embodiment of intra-DU mobility. Figure 5 shows an embodiment of intra-CU and inter-DU mobility. Figure 6 shows an embodiment of inter-CU mobility. In these examples, mobility may be network-triggered as in Figure 7, or user equipment (UE)-triggered as in Figure 8. The NW-triggered mobility from Figure 7 may be further modified depending on whether it is DU-triggered mobility or CU-triggered mobility.

[0113] Specifically, the CU and DU cooperate to add / modify / release candidate cell configuration and trigger events. There are at least four embodiments for the cooperation on candidate cell configuration initiation / preparation. In embodiment 1, the CU determines the proposed candidate cell, and the CU determines the trigger event. In embodiment 2, the CU determines the proposed candidate cell, and the DU determines the trigger event. In embodiment 3, the DU determines the proposed candidate cell, and the DU determines the trigger event. In embodiment 4, the DU determines the proposed candidate cell, and the CU determines the trigger event.

[0114] [Table 4]

[0115] For embodiment 1 and embodiment 2 in which the CU determines the proposed candidate cells, the CU sends the proposed candidate cell list to the DU via an F1 message (e.g., a UE CONTEXT MODIFICATION REQUEST message or other message) to request the DU to configure or set. This message may also include an indication indicating that the procedure is for L1 / L2 mobility, and / or an indication indicating which type of L1 / L2 mobility the procedure is for (e.g., "UE triggered L1 / L2 mobility", "NW triggered L1 / L2 mobility", "CU triggered L1 / L2 mobility", or "DU triggered L1 / L2 mobility"). In embodiment 1, the CU may also send a trigger event to the DU (e.g., in the case of DU triggered mobility).

[0116] For embodiment 1 and embodiment 2 in which the CU determines the proposed candidate cells, the DU sends the accepted or failed / rejected candidate cell list and / or the candidate cell configuration for each accepted candidate cell to the CU via an F1 message (e.g., UE CONTEXT MODIFICATION RESPONSE message or other message). If the DU accepts all the proposed candidate cells, the accepted or failed / rejected candidate cell list is not provided. If the DU fails to configure or configure some candidate cells, the failed / rejected candidate cell list (including the failed candidate cell) or the accepted candidate cell list (including the accepted candidate cell) is provided. The candidate cell configuration may be encapsulated in an RRC container (such as a Handover Preparation Information, CG-Config, or CG-ConfigInfo message). In embodiment 2, the DU may also send a trigger event to the CU (e.g., in the case of UE-triggered mobility or CU-triggered mobility).

[0117] For embodiments 3 and 4 in which the DU determines the proposed candidate cells, the DU sends the requested candidate cell list to the CU via an F1 message (e.g., a UE CONTEXT MODIFICATION REQUIRED message or other message) to request the CU to allow the DU to configure. This message may also include an indication indicating that the procedure is for L1 / L2 mobility and / or an indication indicating which type of L1 / L2 mobility the procedure is for (e.g., "UE triggered L1 / L2 mobility", "NW triggered L1 / L2 mobility", "CU triggered L1 / L2 mobility", or "DU triggered L1 / L2 mobility"). The DU may also provide a candidate cell configuration for each requested candidate cell. The candidate cell configuration may be encapsulated in an RRC container (such as a Handover Preparation Information, CG-Config, or CG-ConfigInfo message). In embodiment 3, the DU may also send a trigger event to the CU (for example, in the case of UE-triggered mobility or CU-triggered mobility).

[0118] For embodiment 3 and embodiment 4 in which the DU determines the proposed candidate cells, the CU sends the accepted or failed / rejected candidate cell list to the DU via an F1 message (e.g., a UE CONTEXT MODIFICATION CONFIRM message). If the CU accepts all requested candidate cells, the accepted or failed / rejected candidate cell list is not provided. If the CU rejects some candidate cells, the failed / rejected candidate cell list (including the failed / rejected candidate cells) or the accepted candidate cell list (including the accepted candidate cells) is provided. In embodiment 4, the CU may also send a trigger event to the DU (e.g., in the case of mobility triggered by the DU).

[0119] The triggering event may include an L1 measurement based event, for example, when the neighbor cell's L1 measurement becomes better than a threshold (e.g., RSRP, RSRQ, or / and SINR values ​​for an A4-like event). In another example, when the neighbor cell's L1 measurement becomes better than the SpCell / serving cell's L1 measurement by more than an offset (e.g., an A3-like event). In another example, when the SpCell / serving cell's L1 measurement becomes worse than a first threshold and the neighbor cell's L1 measurement becomes better than a second threshold (e.g., an A5-like event). In the alternative, the triggering event may include an event based on the L1 measurement on the serving cell and the L3 measurement on the candidate / neighbor cell, for example, when the SpCell / serving cell's L1 measurement becomes worse than a first threshold and the neighbor cell's L3 measurement becomes better than a second threshold (e.g., an A5-like event). In another alternative, the trigger event may include a list of measIds associated with L1 / L3 measurement objects / resources and reporting configurations.

[0120] In embodiments where the information (e.g., triggering event, indication for L1 / L2 mobility) is provided, the information may remain in an F1 message (e.g., UE CONTEXT MODIFICATION REQUEST / RESPONSE, UE CONTEXT MODIFICATION REQUIRED / CONFIRM message) and be forwarded directly to the CU or DU. In another embodiment, the information (e.g., triggering event, indication for L1 / L2 mobility) may be provided in an RRC message (e.g., Handover Preparation Information, CG-Config, or CG-Config Info message), which may be included as an information element (IE) in the F1 message.

[0121] FIG. 9 illustrates an embodiment of intra-DU mobility based on candidate cell preparation initiated by a CU. FIG. 9 is applicable to embodiment 1 and embodiment 2 from Table 4. A user equipment (UE) communicates with a base station distributed unit (DU) and a base station centralized unit (CU). FIG. 4 illustrates intra-DU mobility, and FIG. 9 illustrates intra-DU mobility based on candidate cell preparation initiated by a CU. In block 902, the CU determines proposed candidate cells (eg, according to RRM measurements). The CU sends a proposed candidate cell list to the DU via an F1 message (eg, a UE CONTEXT MODIFICATION REQUEST message or other message) to request the DU to configure or set the candidate cells. This message may also include an indication indicating that the procedure is for L1 / L2 mobility and / or an indication indicating which type of L1 / L2 mobility the procedure is for.

[0122] In block 904, the DU decides whether to configure or set the proposed candidate cells and sends the generated candidate cell configuration (e.g., CellGroupConfig) to the CU (e.g., via a UE CONTEXT MODIFICATION RESPONSE message). If the DU fails to configure or set some candidate cells, the DU may also include in the message an accepted cell list (e.g., containing a list of already successfully configured cells) or a failed / rejected cell list (e.g., containing a list of cells that failed to be configured). The DU may also include in the message the generated triggering events / execution conditions (e.g., in case of mobility triggered by the UE or CU).

[0123] In block 906, the CU sends the generated RRCReconfiguration message to the DU (e.g., via a DL RRC MESSAGE TRANSFER message). The RRC message includes the candidate cell configuration and may also include trigger events / conditions associated with the candidate cell (e.g., in case of UE triggered mobility). In block 908, the DU forwards the received RRCReconfiguration message to the UE. In block 910, the UE responds with an RRCReconfigurationComplete message to the DU, which in turn forwards to the CU in block 912 (e.g., via a UL RRC MESSAGE TRANSFER message). In some embodiments, in block 906, the CU sends the generated trigger event to the DU. In alternative embodiments, blocks 906 and 912 may include a UE CONTEXT MODIFICATION REQUEST message and a UE CONTEXT MODIFICATION RESPONSE message.

[0124] FIG. 10 shows an embodiment of intra-DU mobility based on candidate cell preparation initiated by the DU. FIG. 10 is applicable to embodiment 3 and embodiment 4 from Table 4. FIG. 4 shows intra-DU mobility, and FIG. 10 shows intra-DU mobility based on candidate cell preparation initiated by the DU. In block 1002, the DU determines a proposed candidate cell (eg, according to L1 measurements). The DU sends a requested candidate cell list to the CU via an F1 message (eg, a UE CONTEXT MODIFICATION REQUIRED message or other message) to request the CU to configure or set the candidate cell. The DU may include the generated candidate cell configuration (eg, CellGroupConfig) and / or a trigger event (eg, in case of mobility triggered by the CU or UE) in the message. The message may also include an indication indicating that the procedure is for L1 / L2 mobility and / or an indication indicating which type of L1 / L2 mobility the procedure is for.

[0125] In block 1004, the CU decides whether to accept the candidate cells as requested. If the CU rejects some candidate cells, the CU may also include in the message an accepted cell list (e.g., including a list of already accepted cell IDs) or a failed / rejected cell list (e.g., including a list of already rejected cell IDs). The CU may generate an RRCReconfiguration message including the candidate cell configuration for each accepted cell, and may also include in this message the generated trigger event / execution condition (e.g., in case of UE-triggered mobility), and send the RRC message to the DU via an F1 message (e.g., UE CONTEXT MODIFICATION CONFIRM message or other message). The F1 message may also include the trigger event to the DU (e.g., in case of DU-triggered mobility).

[0126] In block 1006, the DU forwards the received RRCReconfiguration message to the UE. In block 1008, the UE responds with an RRCReconfigurationComplete message to the DU, which the DU forwards to the CU in block 1010 (e.g., via a UL RRC MESSAGE TRANSFER message). In some embodiments, the DU may generate a trigger event after the CU accepts the required candidate cell (e.g., after block 1004) and send the generated trigger event to the CU via a UE CONTEXT MODIFICATION REQUIRED message. The CU then generates and sends an RRC reconfiguration message to the UE via the DU (e.g., sends the generated RRCReconfiguration message to the DU via a DL RRC MESSAGE TRANSFER message), and the DU forwards the received RRCReconfiguration message to the UE.

[0127] Figure 11 shows an embodiment of inter-DU mobility based on candidate cell preparation initiated by a CU. Figure 11 is applicable to embodiment 1 and embodiment 2 from Table 4. Figure 5 shows inter-DU mobility, and Figure 11 shows inter-DU mobility based on candidate cell preparation initiated by a CU. There may be a source DU from which a UE transfers to a candidate DU (also called a target DU). In this example, the CU does not change because this is intra-CU inter-DU mobility.

[0128] In block 1102, the CU determines proposed candidate cells (e.g., according to RRM measurements). The CU sends the proposed candidate cell list to the candidate DU via an F1 message (e.g., a UE CONTEXT SETUP REQUEST message or other message) to request the candidate DU to configure or set the candidate cells. This message may also include an indication that the procedure is for L1 / L2 mobility and / or an indication of what type of L1 / L2 mobility the procedure is for. Before block 1102, in some embodiments, the CU may send a UE CONTEXT MODIFICATION REQUEST message to the source DU to inquire about the latest configuration. The source DU responds with a UE CONTEXT MODIFICATION RESPONSE message that includes the complete configuration information.

[0129] In block 1104, the target DU decides whether to configure or set the proposed candidate cells and sends the generated candidate cell configuration (e.g., CellGroupConfig) to the CU (e.g., via a UE CONTEXT SETUP RESPONSE message). If the target DU fails to configure some candidate cells, the DU may also include in the message an accepted cell list (e.g., containing a list of already successfully configured cells) or a failed / rejected cell list (e.g., containing a list of cells that failed to be configured). In block 1106, the CU may send the configured candidate cell list to the source DU via an F1 message (e.g., UE CONTEXT MODIFICATION REQUEST message). This message may also include a triggering event / execution condition generated by the CU (e.g., in case of DU-triggered mobility). In block 1108, the source DU responds with a UE CONTEXT MODIFICATION RESPONSE message. This message may also include a triggering event / execution condition generated by the DU (e.g., in case of UE-triggered mobility or CU-triggered mobility).

[0130] In block 1110, the CU sends the generated RRC Reconfiguration message to the DU (e.g., via a DL RRC MESSAGE TRANSFER message). The RRC message includes the candidate cell configuration and may also include a triggering event / condition associated with the candidate cell (e.g., in case of UE-triggered mobility). In block 1112, the DU forwards the received RRC Reconfiguration message to the UE. In block 1114, the UE responds with an RRC Reconfiguration Complete message to the DU, which the DU forwards to the CU in block 1116 (e.g., via a UL RRC MESSAGE TRANSFER message). In some embodiments, blocks 1106, 1108 may be skipped. In block 1104, the CU may send the generated RRC reconfiguration message to the source DU (e.g., via a UE CONTEXT MODIFICATION REQUEST message). This message may include the configured candidate cell list and / or triggering events / execution conditions generated by the CU (eg, in case of DU triggered mobility).

[0131] FIG. 12 shows an embodiment of inter-DU mobility based on candidate cell preparation initiated by the DU. FIG. 12 is applicable to embodiment 3 and embodiment 4 from Table 4. FIG. 5 shows inter-DU mobility, and FIG. 12 shows inter-DU mobility based on candidate cell preparation initiated by the DU. In block 1202, the source DU determines a candidate cell (e.g., according to L1 measurements). The DU sends a proposed candidate cell list or / and candidate DU ID to the CU via an F1 message (e.g., UE CONTEXT MODIFICATION REQUIRED message or other message) to request to configure the candidate cell. This message may also include an indication indicating that the procedure is for L1 / L2 mobility and / or an indication indicating which type of L1 / L2 mobility the procedure is for.

[0132] In block 1204, the CU sends the proposed candidate cell list to the candidate DU via an F1 message (e.g., a UE CONTEXT SETUP REQUEST message or other message) to request the candidate DU to configure the candidate cells. This message may also include an indication that this procedure is for L1 / L2 mobility, e.g., an "L1 / L2 Mobility" indicator. In some embodiments, before block 1204, the CU sends a UE CONTEXT MODIFICATION REQUEST message to the source DU to inquire about the latest configuration, and the source DU responds with a UE CONTEXT MODIFICATION RESPONSE message containing the complete configuration information.

[0133] In block 1206, the target DU decides to configure the proposed candidate cells and sends the generated candidate cell configuration (e.g., CellGroupConfig) to the CU (e.g., via a UE CONTEXT SETUP RESPONSE message). If the target DU fails to configure some candidate cells, the DU may also include an accepted cell list (e.g., including a list of already successfully configured cells) or a failed / rejected cell list (e.g., including a list of cells that failed to be configured) in the message. In block 1208, the CU sends the generated RRCReconfiguration message to the DU via an F1 message (e.g., a UE CONTEXT MODIFICATION CONFIRM message). The RRC message includes the candidate cell configuration and may also include trigger events / execution conditions associated with the candidate cells (e.g., in case of UE-triggered mobility). The F1 message may include the configured candidate cell list and / or the trigger events / conditions (e.g., in case of DU-triggered mobility). In block 1210, the DU forwards the received RRCReconfiguration message to the UE. In block 1212, the UE responds with an RRCReconfigurationComplete message to the DU, which in turn transfers to the CU in block 1214 (eg, via a UL RRC MESSAGE TRANSFER message).

[0134] In some embodiments, after block 1206, the CU may send a UE CONTEXT MODIFICATION REQUEST message to the source DU to inform it of the configured / accepted candidate cell list. This message also includes the triggering event / execution condition generated by the CU (e.g., in case of DU triggered mobility), and the source DU responds to the CU with a UE CONTEXT MODIFICATION RESPONSE message. This message includes the triggering event / execution condition generated by the DU (e.g., in case of UE triggered mobility or DU triggered mobility), and the CU sends the generated RRCReconfiguration message to the source DU via an F1 message (e.g., DL RRC MESSAGE TRANSFER message).

[0135] 9-12 can be considered as part of the candidate cell configuration initiation / preparation phase, and FIG. 13-18 can be considered as part of the L1 / L2 mobility trigger phase. The overall procedure of L1 / L2 mobility may be any one of the combinations of part of the candidate cell configuration initiation / preparation phase and part of the L1 / L2 mobility trigger phase. There are several options to trigger L1 / L2 mobility. As mentioned above, there may be NW triggered mobility or UE triggered mobility. For NW triggered mobility, it may be triggered by CU or DU. For CU triggered mobility, CU sends candidate cells to be activated / switched to DU, and DU sends L1 / L2 command to UE to indicate the candidate cells to be activated / switched to. For DU-triggered mobility, the DU sends L1 / L2 commands to the UE to indicate the candidate cells to be activated / switched, and after completion of L1 / L2 mobility (e.g., successful completion of RA to the DU or successful reception of L1 / L2 signaling from the UE at the DU), the DU may notify the CU of the activated or target cells. In one embodiment, the DU only notifies the CU of the activated or target SpCell, but does not notify the CU of the activated or target SCell. If all the candidate cells are activated as SCells (i.e., L1 / L2 mobility is triggered due to addition / change of SCell), the DU may not notify the CU. In another embodiment, the DU notifies all the candidate cells to be activated, including both SpCells and SCells.

[0136] For UE-triggered mobility, the UE directly triggers L1 / L2 mobility when at least one of the execution conditions is met. After completion of L1 / L2 mobility (e.g., successful completion of RA to DU or successful reception of L1 / L2 signaling from UE to DU), the DU may notify the CU of the activated cell or target cell. In one embodiment, the DU only notifies the CU of the activated cell or target SpCell, but does not notify the CU of the activated cell or target SCell. If all the candidate cells are activated as SCells (i.e., L1 / L2 mobility is triggered for adding / changing SCells), the DU should notify the CU. In another embodiment, the DU notifies all the candidate cells to be activated, including both SpCells and SCells.

[0137] FIG. 13 illustrates an embodiment of intra-DU mobility based on a decision triggered by a CU. FIG. 13 is applicable to embodiment 1 and embodiment 4 from Table 4. FIG. 4 illustrates intra-DU mobility, and FIG. 13 illustrates intra-DU mobility based on a decision triggered by a CU. In block 1302, an L1 / L3 measurement report is provided from the UE to the DU, and forwarded to the CU in block 1304. The measurement report is used to determine a candidate cell in block 1306. Blocks 1302 to 1306 have been described in other embodiments.

[0138] In block 1308, after the CU determines the candidate cell to be activated / switched to, for example, according to L1 or / and L3 measurement reports or load balancing, the CU sends the candidate cell to be activated / switched to the DU via an F1 message (e.g., UE CONTEXT MODIFICATION REQUEST message or other message). In block 1310, the DU sends an L1 / L2 command to the UE indicating the candidate cell to be activated / switched to. In block 1312, the UE activates or accesses the target cell (e.g., via a random access procedure) and in block 1314 sends L1 / L2 signaling (e.g., via ACK, UCI, MAC CE) to the DU to complete the L1 / L2 mobility procedure. In block 1316, the DU responds to the CU (e.g., via a UE CONTEXT MODIFICATION RESPONSE message or other message). This message may include the activated cell ID or the target cell ID.

[0139] FIG. 14 illustrates an embodiment of intra-DU mobility based on a decision triggered by the DU. FIG. 14 is applicable to embodiment 2 and embodiment 3 from Table 4. FIG. 4 illustrates intra-DU mobility, and FIG. 14 illustrates intra-DU mobility based on a decision triggered by the DU. In block 1402, a L1 measurement report is provided from the UE to the DU. In block 1404, the DU determines a candidate cell to be activated based on the measurement. In block 1406, after the DU determines the candidate cell to be activated / switched, the DU sends an L1 / L2 command to the UE to indicate the candidate cell to be activated / switched. In block 1408, the UE activates / accesses the target cell (e.g., via a random access procedure), and in block 1410, sends L1 / L2 signaling to the DU to complete the L1 / L2 mobility procedure. In block 1412, the DU may inform the CU of the activated cell or the target cell (e.g., via an ACCESS SUCCESS message).

[0140] FIG. 15 illustrates an embodiment of intra-DU mobility based on a decision triggered by a UE. FIG. 4 illustrates intra-DU mobility, and FIG. 15 illustrates intra-DU mobility based on a decision triggered by a UE. In block 1502, the UE evaluates execution conditions for candidate cells. If at least one candidate cell satisfies the corresponding execution condition, the UE applies / activates the corresponding candidate cell configuration. In block 1504, the UE activates / accesses the target cell (e.g., via a random access procedure) and in block 1506, sends L1 / L2 signaling (e.g., via ACK, UCI, MAC CE) to the DU to complete the L1 / L2 mobility procedure. In block 1508, the DU informs the CU about the successful completion of the L1 / L2 mobility (e.g., via an ACCESS SUCCESS message or other message). This message may include the activated cell ID or the target cell ID.

[0141] FIG. 16 illustrates an embodiment of inter-DU mobility based on a decision triggered by a CU. FIG. 16 is applicable to embodiment 1 and embodiment 4 from Table 4. FIG. 5 illustrates inter-DU mobility, and FIG. 16 illustrates inter-DU mobility based on a decision triggered by a CU. In block 1602, an L1 / L3 measurement report is provided from the UE to the source DU, and forwarded to the CU in block 1604. The measurement report is used to determine a candidate cell in block 1606. Blocks 1602-1606 have been described in other embodiments. In block 1608, the CU determines a candidate cell to be activated / switched (e.g., according to the L1 or / and L3 measurement report, or / and load condition), and the CU sends the candidate cell to be activated / switched to the source DU via an F1 message (e.g., UE CONTEXT MODIFICATION REQUEST message or other message). In block 1610, the source DU sends an L1 / L2 command to the UE indicating the candidate cell to be activated / switched to. The source DU may also send a Downlink Data Delivery Status frame in block 1612 to inform the CU about the downlink data to the UE that has failed to be transmitted. In block 1614, the source DU responds to the CU (e.g., via a UE CONTEXT MODIFICATION RESPONSE message or other message). In block 1616, the UE activates or accesses the target cell (e.g., via a random access procedure) and sends L1 / L2 signaling to the DU in block 1622 to complete the L1 / L2 mobility procedure. After block 1616, the target DU may send a Downlink Data Delivery Status frame in block 1618 to inform the CU. Downlink packets may be sent from the CU to the target DU, including the PDCP PDUs that were not successfully transmitted in the source DU.The target DU may also inform the CU about the successful completion of the L1 / L2 mobility (e.g., via an "ACCESS SUCCESS" message) in block 1620. This message may also include the activated cell or the target cell.

[0142] FIG. 17 illustrates an embodiment of inter-DU mobility based on a decision triggered by a DU. FIG. 17 is applicable to embodiment 2 and embodiment 3 from Table 4. FIG. 5 illustrates inter-DU mobility, and FIG. 17 illustrates inter-DU mobility based on a decision triggered by a DU. In block 1702, an L1 measurement report is provided from the UE to the source DU. In block 1704, the source DU determines a candidate cell to be activated based on the measurement. In block 1706, after the source DU determines a candidate cell to be activated / switched, the source DU sends an L1 / L2 command to the UE to indicate the candidate cell to be activated / switched. The source DU determines a candidate cell to be activated / switched (for example, according to the L1 measurement report), and the source DU sends an L1 / L2 command to the UE to indicate the candidate cell to be activated / switched. The source DU may also send a downlink data delivery status frame in block 1708 to inform the CU about the downlink data to the UE that has failed to be transmitted. In block 1710, the UE activates or accesses the target cell (e.g., via a random access procedure) and sends L1 / L2 signaling to the DU in block 1716 to complete the L1 / L2 mobility procedure. After block 1710, the target DU may send a downlink data delivery status frame in block 1712 to inform the CU. Downlink packets may be sent from the CU to the target DU, including the PDCP PDUs that were not successfully transmitted in the source DU. The target DU may also inform the CU about the successful completion of the L1 / L2 mobility in block 1714 (e.g., via an ACCESS SUCCESS message). This message may also include the activated / target cell.

[0143] FIG. 18 illustrates an embodiment of inter-DU mobility based on a decision triggered by a UE. FIG. 5 illustrates inter-DU mobility, and FIG. 18 illustrates inter-DU mobility based on a decision triggered by a UE. In block 1802, the UE evaluates execution conditions for the candidate cells. If at least one candidate cell satisfies the corresponding execution condition, the UE applies / activates the corresponding candidate cell configuration. In block 1804, the UE activates or accesses the target cell (e.g., via a random access procedure) and sends L1 / L2 signaling to the DU in block 1810 to complete the L1 / L2 mobility procedure. After block 1804, the target DU may notify the CU by sending a downlink data delivery status frame in block 1806. A downlink packet may be sent from the CU to the target DU, including the PDCP PDU that was not successfully transmitted in the source DU. The target DU may also inform the CU about the successful completion of the L1 / L2 mobility (e.g., via an ACCESS SUCCESS message) in block 1808. This message may also include the activated cell or the target cell.

[0144] In block 1812, the CU may also initiate a UE context modification procedure to the source DU to stop data transmission for the UE. The CU sends a UE CONTEXT MODIFICATION REQUEST message to the source DU to instruct it to stop data transmission for the UE. The source DU also sends a downlink data delivery status frame in block 1814 to inform the CU about the downlink data to the UE that has failed to be transmitted. In block 1822, the source DU responds to the CU with a UE CONTEXT MODIFICATION RESPONSE message. In some embodiments, the downlink user data is provided by the CU to the candidate DU in block 1816 and to the UE in block 1818. In block 1820, the uplink user data is provided from the UE to the source DU.

[0145] Control of L1 / L2 mobility triggers

[0146] The CU can control whether the DU is allowed to trigger L1 / L2 mobility (i.e., send L1 / L2 mobility triggering command to the UE). When the CU decides to stop / suspend L1 / L2 mobility triggering (e.g., when the CU decides to trigger L3 mobility via conventional HO (i.e., PCell change), DAPS HO, conventional PSCell addition / change, etc.), the CU sends an indication (e.g., "L / L2 mobility triggering indicator", this indicator is set as "stop / suspend") via an F1 message (e.g., UE CONTEXT MODIFICATION REQUEST message or other message) to indicate to the DU to stop / suspend L1 / L2 mobility triggering. Upon / after receiving the indication, the DU should not send L1 / L2 mobility triggering command to the UE. When the CU decides to resume / restart the L1 / L2 mobility trigger (e.g., upon completion of L3 mobility), the CU sends an indication (e.g., "L / L2 mobility triggering indicator", which is set as "restart / resume") via an F1 message (e.g., UE CONTEXT MODIFICATION REQUEST message or other message) to indicate to the DU to resume / restart the L1 / L2 mobility trigger. Upon / after receiving the indication, the DU can resume sending L1 / L2 mobility trigger commands to the UE, e.g., if it is determined that a trigger event is met.

[0147] The DU may request to restart / resume the L1 / L2 mobility trigger, for example, when it is determined that a triggering event is met. The DU sends an indication (e.g., an "L / L2 mobility triggering request indicator") via an F1 message (e.g., a UE CONTEXT MODIFICATION REQUIRED message or other message) to request the CU to allow the restart of the L1 / L2 mobility trigger. The CU decides whether to accept the request or not and sends a response to the DU via an F1 message (e.g., a UE CONTEXT MODIFICATION CONFIRM or UE CONTEXT MODIFICATION REFUSE message). If the CU rejects the request, it may also include a cause (e.g., L3 mobility triggered) in the response message.

[0148] Mobility Exchange

[0149] In alternative embodiments, L1 / L2 mobility may interact with other functions such as handover (HO), conditional handover (CHO), conditional PSCell addition / modification (CPAC), dual active protocol stack (DAPS), or other functions. In one embodiment, L1 / L2 mobility configuration may include these other functions. L1 / L2 mobility may be combined with CHO / CPAC (i.e., UE-triggered L1 / L2 mobility), where the UE automatically triggers L1 / L2 mobility based on pre-configured execution conditions and stored candidate cell configuration. In another example, L1 / L2 mobility may be combined with DAPS, such that the UE maintains source cell connection when triggering L1 / L2 mobility to a target candidate cell.

[0150] In alternative embodiments, these other functions may be modified to include L1 / L2 mobility configuration. For example, conventional HO, conventional PSCell addition / modification, CHO, CPAC, DAPS, or HO configuration may be modified to include candidate cell configuration for L1 / L2 mobility. In other words, L1 / L2 mobility configuration is based on target cell configuration, and L1 / L2 mobility (if triggered) can be performed after the completion of the other functions. Alternatively, L1 / L2 mobility and other functions may be independently configured in the UE.

[0151] If L1 / L2 mobility is already configured (i.e. the UE has a stored candidate cell configuration), the source cell / node may want to initiate or prepare an L3 PCell modification (e.g. conventional HO, CHO, DAPS, etc.) and / or an L3 PSCell addition / modification (e.g. conventional PSCell addition / modification, CPAC, etc.). The source cell / node may send information to the target cell / node to transfer / maintain / remove the candidate cell configuration. In one embodiment, this information may include the candidate cell configuration, e.g. candidate cell ID and each cell configuration. In some embodiments, there may be a list of candidate cells to be maintained / removed. In another embodiment, this information may include an indication of whether to maintain / remove the candidate cell configuration within the configuration of other functions. For example, the indication may indicate whether to maintain / remove the candidate PCell configuration, the candidate PSCell configuration, the candidate SpCell configuration, and / or the candidate SCell configuration (e.g. "maintainCandidatePCell", "maintainCandidatePSCell", "maintainCandidateSpCell", "maintainCandidateSCell"). In another embodiment, this information may include an indication as to which candidate cell configurations may be considered as baseline / reference for delta configuration of the target cell configuration in the configuration of other functions (e.g., the indication indicates one or more candidate cell IDs as baseline cells). For example, the indication may indicate which candidate cell configurations may be considered as baseline / reference for delta configuration of the target PCell, target PSCell, target SpCell, or / and target SCell (e.g., "baselineForPCell", "baselineForPSCell", "baselineForSpCell", "baselineForSCell"). Other functions may have different configurations (e.g., conventional HO / conventional PSCell addition / modification / CHO / CPAC / DAPS HO configuration).

[0152] In embodiments where the information is provided, the information may be forwarded directly to the target cell / node by including the information in an Xn / X2 message (e.g., an HO request message, an SN addition request message, or an SN change required message). In another embodiment, the information may be provided in an RRC message (e.g., a Handover Preparation Information, a CG-Config, or a CG-Config Info message), which may be included as an information element in the Xn / X2 message.

[0153] There may be alternatives for what to do with the stored L1 / L2 mobility configuration when the other functions are triggered or executed first. In one embodiment, the UE may remove the stored L1 / L2 mobility configuration (e.g., candidate cell configuration). For example, the UE may remove the stored L1 / L2 mobility configuration following an explicit instruction from the source cell. Here, the source cell explicitly releases the candidate cell configuration via an RRC message (e.g., an RRC reconfiguration message) before sending the HO / PSCell addition / modification command to the UE. In an alternative embodiment, the UE may remove the stored L1 / L2 mobility configuration following an explicit instruction from the target cell. For example, the target cell explicitly releases the candidate cell configuration within the command of the other functions (e.g., includes an indication indicating the removal of the stored candidate cell configuration within the RRC reconfiguration message). In another example, the target cell may explicitly indicate within the command of the other functions which candidate cell configuration should be released (e.g., includes a list of candidate cells to be released within the RRC reconfiguration message). In another example, the UE autonomously removes the stored L1 / L2 mobility configuration when execution of other functions is triggered, for example, when it receives an L3 mobility command (e.g., an RRC reconfiguration message for HO and / or PSCell addition / modification) or when it triggers execution of conditional L3 mobility (e.g., execution conditions for CHO / CPAC are met). In another example, the UE autonomously removes the stored L1 / L2 mobility configuration when execution of other functions is completed, for example, upon completion of RA to the target cell.

[0154] In other embodiments where other functions are triggered or executed first, the L1 / L2 mobility configuration may be maintained by the UE through the stored L1 / L2 mobility configuration. For example, the UE maintains the stored L1 / L2 mobility configuration according to an explicit instruction from the target cell. This explicit instruction may be from the target cell, which explicitly instructs the other functions' command to maintain the candidate cell configuration (e.g., includes an instruction in an RRC reconfiguration message to maintain the stored candidate cell configuration). In another example, the target cell explicitly instructs the other functions' command which candidate cell configurations should be maintained (e.g., includes a list of released / maintained candidate cells in an RRC reconfiguration message).

[0155] In another embodiment, the UE may maintain the stored L1 / L2 mobility configuration without an explicit instruction. When maintaining the L1 / L2 mobility configuration, other functions may be triggered / executed first, as described above. The handling of the execution condition evaluation (i.e., in case of UE-triggered L1 / L2 mobility) may be handled when the execution of other functions is triggered. For example, the UE automatically stops the evaluation of the execution condition (e.g., for all candidate cells, for only L1 / L2 mobility candidate cells in the MCG, or for only L1 / L2 mobility candidate cells in the SCG). Alternatively, the UE may stop the evaluation of the execution condition following an explicit instruction from the network (e.g., the target cell). The instruction may be an explicit instruction in an RRC message (e.g., an RRC reconfiguration message) or in a MAC CE to stop the execution condition evaluation for candidate cells (e.g., for all candidate cells, for only L1 / L2 mobility candidate cells in the MCG, or for only L1 / L2 mobility candidate cells in the SCG).

[0156] If the UE successfully completes the execution of other functions (e.g., completing an RA to the target cell), the UE may remove the stored L1 / L2 mobility configuration. Alternatively, the UE may re-initiate evaluation of the execution conditions for UE-triggered L1 / L2 mobility (e.g., for all candidate cells, for only L1 / L2 mobility candidate cells in the MCG, or for only L1 / L2 mobility candidate cells in the SCG).

[0157] In some embodiments, the removal of stored L1 / L2 mobility configurations may depend on what type of function was performed. For example, if the function is related to MCG (e.g., HO / CHO / DAPS), the UE may remove only L1 / L2 mobility configurations in MCG, only L1 / L2 mobility configurations in SCG, or both MCG and SCG (i.e., all candidate cell configurations). In another example, if the function is related to SCG (e.g., PSCell Addition / Modification / CPACS), the UE may remove only L1 / L2 mobility configurations in MCG, only L1 / L2 mobility configurations in SCG, or both MCG and SCG (i.e., all candidate cell configurations).

[0158] The above embodiment relates to L1 / L2 mobility being triggered first. In alternative embodiments, other functions may be triggered or executed first. There may be different alternatives when other functions are triggered first, such as when CHO / CPAC and L1 / L2 mobility are independently configured for the UE (e.g., the UE stores both CHO / CPAC candidate cell configuration and L1 / L2 mobility candidate cell configuration), or when the UE triggers L1 / L2 mobility (e.g., receives NW-triggered 1 / L2 command or triggers UE-triggered L1 / L2 mobility execution). The alternatives include whether the UE removes the stored CHO / CPAC configuration, or whether the UE keeps the stored CHO / CPAC configuration but stops evaluating CHO / CPAC. If the UE successfully completes the L1 / L2 mobility (e.g., completing an RA to the target cell or sending L1 / L2 signaling to the target cell), the UE may remove the stored CHO / CPAC configuration. Alternatively, the UE may restart the evaluation of CHO / CPAC. In some embodiments, the removal of the stored CHO / CPAC configuration may depend on what type of L1 / L2 mobility is performed. For example, if the L1 / L2 mobility is for a cell change within the MCG (e.g., PCell change, MCG SCell addition / change), the UE may remove only the CHO configuration, only the CPAC configuration, or both the CHO and CPAC configurations. In another example, if the L1 / L2 mobility is for a cell change within the SCG (e.g., PSCell addition / change, SCG SCell addition / change), the UE may remove only the CPAC configuration, or both the CHO and CPAC configurations.

[0159] The above-mentioned embodiments relate to L1 / L2 mobility being triggered first, or other functions being triggered first. However, there are also embodiments in which other functions and L1 / L2 mobility are triggered simultaneously or substantially simultaneously. If the trigger conditions for CHO / CPAC and L1 / L2 mobility are met simultaneously (e.g., the UE detects that a CHO / CPAC execution condition is met and detects that an L1 / L2 mobility execution condition is met or receives an L1 / L2 mobility command from the NW), the UE may execute one function first according to the following alternatives regarding priority: ● CHO>L1 / L2 mobility for PCell change>CPAC>L1 / L2 mobility for PSCell change>L1 / L2 mobility for SCell change ● L1 / L2 mobility for PCell change > CHO > L1 / L2 mobility for PSCell change > CPAC > L1 / L2 mobility for SCell change.

[0160] Dealing with mobility interaction failures

[0161] When conditional L3 mobility (e.g., CHO, CPAC) and L1 / L2 mobility are configured simultaneously, upon detecting L1 / L2 mobility failure, the UE may continue conditional L3 mobility evaluation and select one conditional L3 mobility candidate cell to perform conditional L3 mobility when an execution condition (e.g., conditional L3 mobility execution condition or additional pre-configured threshold for failure recovery) is met. In one embodiment, upon detecting L1 / L2 mobility for PCell change failure, the UE continues CHO evaluation and selects one CHO candidate cell to perform CHO when an execution condition (e.g., CHO execution condition or additional pre-configured threshold for failure recovery) is met. In one embodiment, upon detecting L1 / L2 mobility for PSCell change failure, the UE continues CPAC evaluation and selects one CPAC candidate cell to perform CPAC when an execution condition (e.g., CPAC execution condition or additional pre-configured threshold for failure recovery) is met.

[0162] Measurement measures for conditional mobility

[0163] In conditional mobility (e.g., CHO, CPAC, UE-triggered L1 / L2 mobility), the NW (e.g., MN, SN) may generate / configure individual measurement gaps for the UE and send them to the UE via RRC signaling (e.g., RRCReconfiguration message with conditional mobility configuration). For example, introduce conditional reconfiguration related measurement gaps (e.g., conditionalReconfigurationGap) in the existing conditionalReconfiguration IE. The conditional reconfiguration related measurement gaps are used by the UE only during conditional mobility evaluation. During conditional mobility preparation, the source node (e.g., source SN, source MN) may send original / source measurement gap configurations to the target node (e.g., target SN, target MN). The target node generates measurement gaps for candidate cells (i.e., measurement gap configurations included in the candidate cell configuration) based on the original / source measurement gap configurations.

[0164] When the UE receives a conditional reconfiguration related measurement gap, the UE may ignore the original / source measurement gap but may store two sets of measurement gap configurations (i.e., the original measurement gap configuration and the conditional reconfiguration related measurement gap). When the execution of conditional mobility is triggered, the UE applies the measurement gap configuration for the candidate cell based on the original / source measurement gap configuration. Upon successful completion of conditional mobility or when the execution of conditional mobility is triggered, the UE may remove the conditional reconfiguration related measurement gap.

[0165] Mobility interactions in idle / inactive state

[0166] There are several alternative embodiments for dealing with L1 / L2 mobility configurations (e.g., candidate cell configurations) when the UE enters the RRC_INACTIVE / IDLE state. In a first embodiment, the NW explicitly indicates via RRC signaling whether the UE should store / maintain / retain or remove candidate cell configurations when it enters the RRC_INACTIVE / IDLE state (e.g., includes an indicator in the RRCRelease message). The UE stores / maintains / retains or removes the stored candidate cell configurations when it enters the RRC_INACTIVE / IDLE state based on the explicit indication. In a second embodiment, the NW explicitly indicates via RRC signaling which candidate cell configurations the UE can store / maintain / retain or remove when it enters the RRC_INACTIVE / IDLE state (e.g., includes a list of cell IDs to be kept or a list of cell IDs to be removed in the RRCRelease message). The UE stores / maintains / retains or removes the indicated candidate cell configurations when it enters the RRC_INACTIVE / IDLE state based on the explicit indication. In a third embodiment, the UE autonomously deletes the stored candidate cell configuration upon entering the RRC_INACTIVE / IDLE state (e.g., upon receiving an RRCRelease message with / without suspendConfig). In a fourth embodiment, the UE maintains the stored candidate cell configuration upon entering the RRC_INACTIVE / IDLE state.

[0167] If the L1 / L2 mobility configuration is maintained during RRC_INACTIVE, there are several alternative embodiments for handling the stored configuration upon RRC connection resumption (e.g., transition from RRC_INACTIVE to RRC_CONNECTED state). In a first embodiment, the NW explicitly instructs the UE to resume / activate one or more candidate cells via RRC signaling (e.g., includes one or more candidate cell IDs to be resumed / activated in the RRCResume message). The UE resumes / activates the indicated candidate cells upon receipt of the RRC signaling based on the explicit instruction. In a second embodiment, the NW explicitly instructs the UE to restore one or more candidate cell configurations, which may be a baseline for subsequent delta configurations to add / modify serving cells (e.g., includes one or more candidate cell IDs to be restored in the RRCResume message). Also, the NW may include delta configurations based on the indicated cell configurations via RRC signaling. The UE restores the indicated candidate cell configuration upon receipt of the RRC signaling based on the explicit instruction. The UE may apply the received delta configuration based on the indicated cell configuration (if any).

[0168] Multi-Connection

[0169] The L1 / L2 based inter-cell mobility mechanism may also be used in a multi-connection architecture (i.e., multiple cell group configurations can be pre-configured by the NW). Multi-connection may be referred to as Multi-Radio Dual Connectivity (MR-DC). The embodiments described throughout may be applied to any multi-connection / MR-DC environment or architecture. Here, a "candidate cell" may be referred to as a "candidate cell group" (e.g., MCG, SCG) for multi-connection / MR-DC. Dynamic cell group activation / switching may be triggered by the NW via RRC signaling (e.g., RRC reconfiguration message) or L1 / L2 command (e.g., DCI, MAC CE). The UE may also trigger cell group activation / switching based on pre-configured execution conditions and candidate cell group configurations. Applying the embodiments to multi-connection / MR-DC may include selective activation / switching. Here, a "candidate cell" may be referred to as a "candidate cell group" (e.g., MCG, SCG) for multi-connection / MR-DC.

[0170] The systems and processes described above may be encoded in a signal-bearing medium, a computer-readable medium such as a memory, programmed in a device such as one or more integrated circuits, one or more processors, or processed by a controller or computer. The data may be analyzed in a computer system and used to generate a spectrum. If the method is performed by software, the software may reside in a memory embedded in or interconnected with a storage device, a synchronization device, a communication interface, or a non-volatile or volatile memory in communication with a transmitter. A circuit or electronic device is provided to transmit the data to another location. The memory may include an ordered list of executable instructions to implement a logical function. The described logical functions or system elements may be implemented through optical circuitry, digital circuitry, through source code, through analog circuitry, through analog sources such as analog electrical, audio or video signals, or a combination. The software may be implemented in any computer-readable or signal-bearing medium for use by or in connection with an instruction-executable system, device, or apparatus. Such a system may comprise a computer-based system, a processor-equipped system, or another system that may selectively obtain instructions from an instruction-executable system, device, or appliance capable of executing the instructions.

[0171] "Computer-readable medium", "machine-readable medium", "propagating signal" medium, and / or "signal-bearing medium" may include any device that stores, communicates, propagates, or transmits software for use by or in connection with an instruction-executable system, apparatus, or device. The machine-readable medium may optionally be, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, device, or propagation medium. A non-exhaustive list of examples of machine-readable media includes an electrical connection having one or more wires, a portable magnetic or optical disk, a random access memory "RAM", a read-only memory "ROM", a volatile memory such as an erasable programmable read-only memory (EPROM or flash memory), or an optical fiber. The machine-readable medium may also include a tangible medium on which the software is printed, since the software may be stored electronically as an image or in another form (e.g., through optical scanning), compiled, and / or interpreted or otherwise processed. The processed medium may then be stored in the computer and / or machine memory.

[0172] The illustrations of the embodiments described herein are intended to provide a general understanding of the configuration of the various embodiments. The illustrations do not completely describe all elements and features of the apparatus and systems that utilize the configurations or methods described herein. Upon reading this disclosure, many other embodiments may be apparent to those skilled in the art. Other embodiments may be utilized and derived from this disclosure, such that structural and logical substitutions and modifications may be made without departing from the scope of the disclosure. Furthermore, the illustrations are merely representative and may not be drawn to scale. Certain proportions within the illustrations may be exaggerated and other proportions may be minimized. Thus, the disclosure and drawings should be considered illustrative and not limiting.

[0173] One or more embodiments of the present disclosure may be referred to herein by the term "invention", individually and / or collectively, merely for convenience and without any intention to limit the scope of the present application to any particular invention or inventive concept. Also, although specific embodiments have been illustrated and described herein, it should be understood that any subsequent arrangements designed to achieve the same or similar purpose may be substituted for the specific embodiment shown. The present disclosure is intended to cover all subsequent adaptations or modifications of the various embodiments. Combinations of the above embodiments with other embodiments not specifically described herein will be apparent to those skilled in the art upon reading the specification.

[0174] "Coupled to" means directly connected or indirectly connected through one or more intermediate components. Such intermediate components may include both hardware and software based components. The arrangement and type of components may be changed without departing from the spirit or scope of the claims as set forth herein. Additional, different, or fewer components may be provided.

[0175] The subject matter disclosed above should be considered as illustrative and not restrictive, and the appended claims are intended to cover all modifications, extensions and other embodiments as falling within the true spirit and scope of the present invention. Accordingly, the scope of the present invention is to be determined by the broadest permissible interpretation of the following claims and their equivalents, as permitted by law, and is not to be limited or restricted by the above detailed description. Although various embodiments of the present invention have been described, it will be apparent to those skilled in the art that many more embodiments and implementations are possible within the scope of the present invention. Accordingly, the present invention is not to be limited, except in light of the appended claims and their equivalents.

Claims

1. 1. A method for wireless communication, comprising: receiving a configuration message including a plurality of candidate cells having configuration and cell identification ("ID") information for each of the plurality of candidate cells; transmitting a measurement report including at least one of a Layer 1 ("L1") measurement or a Layer 3 ("L3") measurement for at least one of the candidate cells; receiving a command identifying at least one of the candidate cells based on the measurement report; transmitting a communication to the identified at least one candidate cell based on the command and the configuration of the identified candidate cell; The method includes:

2. The measurement reports and the communications are sent from a user equipment ("UE") to a base station, and the UE receives the configuration messages and the commands from the base station. The method of claim 1.

3. The command is Layer 1 or Layer 2 ("L1 / L2") signaling, and the communication sent to the identified candidate cell is L1 / L2 signaling, the L1 signaling including at least one of Downlink Control Information ("DCI"), Uplink Control Information ("UCI"), and Physical Layer Acknowledgement ("ACK") signaling, and the L2 signaling including Media Access Control Element ("MAC CE"). The method of claim 1.

4. The command includes cell ID information of the identified candidate cell that is to be activated. The method according to claim 1 or 3.

5. The cell ID information includes at least one of a candidate cell configuration index, a serving cell ID, a physical cell identity ("PCI"), a PCI and frequency, a reference signal ("RS") ID associated with the candidate cell, or a transmission configuration indicator ("TCI") state ID associated with the candidate cell. The method according to claim 1 or 4.

6. The candidate cells include separate lists for any of the candidate cells configured as special cells ("SpCells") or any of the candidate cells configured as secondary cells ("SCells"), and the identification is based on the separate lists. The method of claim 1.

7. The candidate cells include a list, each of which can be configured as a special cell ("SpCell") or a secondary cell ("SCell"). The method of claim 1.

8. The candidate cells include a list, each of which can be configured as a candidate cell for both a special cell ("SpCell") and a secondary cell ("SCell"). The method of claim 1.

9. The measurement report is triggered based on a condition from the UE, the condition including at least one of an event being met based on Layer 1 measurements of at least one candidate cell, an out of sync indication from a serving cell or a special cell ("SpCell"), or a failure of a serving cell or the SpCell. The method of claim 1.

10. The command: a timing advance ("TA") value or a compensated TA value of the identified candidate cell; and a Cell Radio Network Temporary Identifier ("C-RNTI") of the identified candidate cell; and an activation DL / UL bandwidth part ("BWP") ID of the identified candidate cell; and an initial TCI state of the identified candidate cell; a serving cell ID of the identified candidate cell; an indication indicating whether a RACH procedure to the identified candidate cell is skipped; and an indication of whether the UE should maintain a connection with the current serving cell; and an indication of whether the identified candidate cell is to be activated as a special cell ("SpCell"); and an indication indicating whether PDCP overlap is activated after accessing the identified candidate cell; and The method of claim 1 , comprising at least one of:

11. activating a stored cell configuration of the identified candidate cell; applying a stored cell configuration of the identified candidate cell; or performing mobility from the current serving cell to the identified candidate cell; The method of claim 1 , further comprising at least one of:

12. and starting a timer for the activation or the mobility, the timer being a media access control ("MAC") layer timer or a radio resource control ("RRC") layer timer. The method of claim 11.

13. The timer is stopped based on a condition, the condition including at least one of a successful transmission of a communication to the identified candidate cell, a failure of a current serving cell, or information from a higher layer indicating the stopping of the timer. The method of claim 12.

14. determining a failure for the activation or the mobility based on expiration of the timer; The method of claim 12 further comprising:

15. reporting a failure of the activation or the mobility to the base station, the failure being reported via a MAC CE or an RRC signaling; notifying a higher layer of the failure of the activation or the mobility; or selecting another cell from the candidate cells and performing another activation of the selected another cell or another mobility to the selected another cell; The method of claim 14 , further comprising at least one of:

16. activating the identified candidate cell; If the identified candidate cell is to be activated as a primary cell ("PCell"), a serving cell identity is set to zero, and if the identified candidate cell is to be activated as a secondary cell ("SCell") or a primary secondary cell ("PSCell"), the serving cell identity is set based on the received identity information for the identified candidate cell. The method of claim 1.

17. receiving a message from the base station; removing the stored candidate cell configuration based on receipt of the message; and The method of claim 1 further comprising:

18. receiving a message from the base station including at least one of an indicator to remove all stored candidate cell configurations or to remove a portion of the candidate cells; removing the stored candidate cell configuration based on the indicator or an indicated candidate cell to be removed; The method of claim 1 further comprising:

19. The message is at least one of a handover command, a primary secondary cell ("PSCell") addition / modification command, or a message ordering the release of a radio resource control ("RRC") connection or the suspension of the RRC connection.

19. The method according to claim 17 or 18.

20. receiving a message from the base station resuming a suspended radio resource control ("RRC") connection; The message includes one or more candidate cells to be resumed, activated, maintained, or restored. The method of claim 1.

21. The candidate cell refers to a candidate cell group; The candidate cell group is at least one of a candidate master cell group ("MCG") or a candidate secondary cell group ("SCG").

21. The method according to any one of claims 1 to 20.

22. 1. A method for wireless communication, comprising: transmitting a configuration message including a plurality of candidate cells having configuration and cell identification (ID) information for each of the plurality of candidate cells; receiving a measurement report for at least one of the candidate cells, the measurement report including at least one of a Layer 1 ("L1") measurement or a Layer 3 ("L3") measurement; transmitting a command identifying at least one of the candidate cells based on the measurement report; receiving, at the identified at least one candidate cell, a communication based on the command and the configuration of the identified candidate cell; A method comprising:

23. The configuration messages and the commands are sent from a base station to a user equipment ("UE"), and the base station receives the measurement reports and the communications from the UE.

23. The method of claim 22.

24. The command is Layer 1 or Layer 2 ("L1 / L2") signaling, and the communication received at the identified candidate cell is L1 / L2 signaling, the L1 signaling including at least one of Downlink Control Information ("DCI"), Uplink Control Information ("UCI"), and Physical Layer Acknowledgement ("ACK") signaling, and the L2 signaling including Media Access Control Element ("MAC CE").

24. The method of claim 23.

25. The command includes cell ID information of the identified candidate cell that is to be activated.

25. The method of claim 22 or 24.

26. The cell ID information includes at least one of a candidate cell configuration index, a serving cell ID, a physical cell identity ("PCI"), a PCI and frequency, a reference signal ("RS") ID associated with the candidate cell, or a transmission configuration indicator ("TCI") state ID associated with the candidate cell.

26. The method of claim 22 or 25.

27. The candidate cells include separate lists for any of the candidate cells configured as special cells ("SpCells") or any of the candidate cells configured as secondary cells ("SCells"), and the identification is based on the separate lists.

23. The method of claim 22.

28. The candidate cells include a list, each of which can be configured as a special cell ("SpCell") or a secondary cell ("SCell").

23. The method of claim 22.

29. The candidate cells include a list, each of which can be configured as a candidate cell for both a special cell ("SpCell") and a secondary cell ("SCell").

23. The method of claim 22.

30. The command: a timing advance ("TA") value or a compensated TA value of the identified candidate cell; and a Cell Radio Network Temporary Identifier ("C-RNTI") of the identified candidate cell; and an activation DL / UL bandwidth part ("BWP") ID of the identified candidate cell; and an initial TCI state of the identified candidate cell; a serving cell ID of the identified candidate cell; an indication indicating whether a RACH procedure to the identified candidate cell is skipped; and an indication of whether the UE should maintain a connection with the current serving cell; and an indication of whether the identified candidate cell is to be activated as an SpCell; and an indication indicating whether PDCP overlap is activated after accessing the identified candidate cell; and 23. The method of claim 22, comprising at least one of:

31. and transmitting a message to the UE including at least one of an indicator to remove all stored candidate cell configurations or a plurality of candidate cells to be removed; The UE removes the stored candidate cell configuration based on the indicator or the indicated candidate cells to be removed.

24. The method of claim 23.

32. The message is at least one of a handover command, a primary secondary cell ("PSCell") addition / modification command, or a message ordering the release of a radio resource control ("RRC") connection or the suspension of the RRC connection.

32. The method of claim 31 .

33. and transmitting to the UE a message resuming a suspended RRC connection, the message including at least one of a candidate cell to be resumed, activated, maintained, or restored.

24. The method of claim 23.

34. The candidate cell refers to a candidate cell group; The candidate cell group is at least one of a candidate master cell group ("MCG") or a candidate secondary cell group ("SCG"). The method according to any one of claims 22 to 33.

35. A wireless communication device comprising a processor and a memory, The processor is configured to read code from the memory and to implement a method according to any one of claims 1 to 34. Wireless communication device.

36. A computer program product including a computer-readable program medium having code stored thereon. The code, when executed by a processor, causes the processor to implement the method of any one of claims 1 to 34. Computer program products.

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