Configuration processing at user equipment

Abstract

A radio access network (RAN) for configuring a user equipment (UE) sends (1802) to the UE (i) a conditional configuration related to a base station operating in the RAN and (ii) a condition to be satisfied by the UE before the UE applies the conditional configuration during a conditional procedure, determines (1804) that the UE is to perform an immediate procedure related to the RAN after the sending, and provides (1806) to the UE an indication that the UE releases the conditional configuration.

Description

Technical Field

[0001] This disclosure generally relates to wireless communications, and more specifically, to the management of configurations related to conditional procedures such as conditional handover, conditional secondary node addition, and conditional primary secondary cell addition procedures. Background Technology

[0002] The purpose of providing this background description is to present the overall context of this disclosure. To the extent described in this background section, the work of the currently named inventors, and other aspects of the description that may otherwise not conform to the prior art at the time of filing, are neither explicitly nor implicitly considered to be prior art to this disclosure.

[0003] In telecommunications systems, the Packet Data Convergence Protocol (PDCP) sublayer of the radio protocol stack provides services such as the delivery, encryption, and integrity protection of user plane data. For example, the PDCP layer, defined for the Evolved Universal Terrestrial Radio Access (EUTRA) radio interface (see 3GPP specification TS 36.323) and New Radio (NR) (see 3GPP specification TS 38.323), provides the ordering of Protocol Data Units (PDUs) in the uplink direction (from the user equipment (UE) to the base station) and in the downlink direction (from the base station to the UE). Furthermore, the PDCP sublayer provides Signaling Radio Bearers (SRBs) and Data Radio Bearers (DRBs) to the Radio Resource Control (RRC) sublayer. Generally, the UE and base station can use SRBs to exchange RRC messages and Non-Access Stratum (NAS) messages, and can use DRBs to transport data on the user plane.

[0004] UEs can use several types of SRBs and DRBs. When operating in dual connectivity (DC), the cell associated with the base station operating as the primary node (MN) defines the primary cell group (MCG), and the cell associated with the base station operating as the secondary node (SN) defines the secondary cell group (SCG). The so-called SRB1 resource carries RRC messages, which in some cases include NAS messages on the dedicated control channel (DCCH), and the SRB2 resource supports RRC messages including recorded measurement information or NAS messages (also on the DCCH, but with a lower priority than the SRB1 resource). More generally, the SRB1 and SRB2 resources allow the UE and MN to exchange MN-related RRC messages as well as embedded SN-related RRC messages, and can also be referred to as MCGSRB. The SRB3 resource allows the UE and SN to exchange SN-related RRC messages and can be referred to as SCG SRB. Separate SRBs allow the UE to exchange RRC messages directly with the MN via lower-layer resources of the MN and SN. Furthermore, a DRB terminated at MN and using only the low-level resources of MN can be called an MCG DRB, a DRB terminated at SN and using only the low-level resources of SN can be called an SCG DRB, and a DRB terminated at MCG but using the low-level resources of MN, SN, or both MN and SN can be called a split DRB.

[0005] In some scenarios, a UE can simultaneously utilize the resources of multiple Radio Access Network (RAN) nodes (e.g., components of base stations or distributed base stations) interconnected via backhaul. This type of connection is called Multiple Radio Dual Connectivity (MR-DC) when these network nodes support different Radio Access Technologies (RATs). When a UE operates in an MR-DC, one base station can operate as the primary node (MN) covering the primary cell (PCell), and another base station can operate as the secondary node (SN) covering the primary secondary cell (PSCell). The UE can communicate with both the MN (via PCell) and the SN (via PSCell). In other scenarios (sometimes called Single Connectivity (SC)), a UE can utilize the resources of only one base station at a time. One base station and / or the UE can determine that the UE should establish a radio connection with another base station. For example, one base station can determine to hand over the UE to a second base station and initiate a handover procedure.

[0006] 3GPP specification TS 37.340 (v15.7.0) describes the procedures for a UE to add or change an SN or PSCell in a DC scenario. These procedures involve message passing between RAN nodes (e.g., RRC signaling and preparation). This message passing typically results in latency, which in turn increases the likelihood that the SN (or PSCell) add or change procedure will fail. Procedures that do not involve checking conditions at the UE can be referred to as "immediate" SN (or PSCell) add and "immediate" SN (or PSCell) change procedures.

[0007] In both SC and DC operations, the UE can also perform a handover procedure to transfer from one cell to another. Depending on the scenario, the UE can transfer from a cell of a first base station to a cell of a second base station, or from a cell of a first distributed element (DU) of a base station to a cell of a second DU of the same base station. 3GPP specifications 36.300v15.6.0 and 38.300v15.6.0 describe a handover procedure involving several steps (RRC signaling and preparation) between RAN nodes, which introduces latency in the handover procedure and thus increases the risk of handover failure. This procedure, which does not involve checking conditions at the UE, can be referred to as an "on-demand" handover procedure.

[0008] Recently, "conditional" procedures (i.e., conditional SN (or PSCell) addition / modification and conditional handover) have been considered for both SN (or PSCell) addition / modification and handover. Unlike the "immediate" procedures discussed above, which are executed unconditionally (i.e., without checking for (multiple) conditions), these procedures do not add or modify the SN (or PSCell) or perform a handover until the UE determines that the condition is met. As used herein, the term "condition" can refer to a single detectable state or event (e.g., a specific signal quality metric exceeds a threshold), or a logical combination of such states or events (e.g., "condition A and condition B" or "(condition A or condition B) and condition C," etc.).

[0009] To configure the conditional procedures, the RAN provides the UE with conditions and configurations (e.g., one or more random access preambles, physical layer configurations, media access control configurations, radio link control configurations, etc.) that, when the conditions are met, enable the UE to communicate with the appropriate base station or via the appropriate cell. For example, for the conditional addition of a base station as an SN (or a candidate cell as a PSCell), the RAN provides the UE with the conditions that must be met before the UE can add a base station as an SN (or a candidate cell as a PSCell), and the configurations that enable the UE to communicate with that base station (or PSCell) after the conditions are met.

[0010] In some cases, the RAN can provide conditional configuration to the UE, and the RAN can configure the UE to execute immediate procedures before the UE completes or initiates the corresponding conditional procedure. However, in some of these scenarios, the UE and / or the RAN do not process the conditional configuration correctly. Summary of the Invention

[0011] Generally, UEs operating in a RAN and one or more base stations implement the techniques of this disclosure to efficiently manage conditional configurations associated with conditional procedures, particularly when the RAN determines that the UE should execute an immediate procedure that replaces the conditional procedure or otherwise makes it unnecessary for the conditional procedure to release the conditional configuration. As used herein, the term "conditional configuration" refers to a configuration associated with a condition that must be met before the UE can communicate with a candidate base station or via a candidate cell when the conditional procedure is executed. In contrast, "immediate configuration" does not require the UE to check for such a condition when executing an immediate procedure. Using these techniques, the UE can, for example, determine whether it should release a received conditional configuration associated with a candidate SN (C-SN) or candidate handover / target cell.

[0012] In some implementations, the RAN notifies the UE whether to release the conditional configuration by providing an indication that the UE releases the conditional configuration. In some implementations, this indication may include a message containing a release indicator that instructs the UE to release the conditional configuration. In other implementations, the indication may include instructions for initiating an immediate procedure, which serves as an implicit instruction for releasing the conditional configuration.

[0013] An example implementation of these technologies is a method in a RAN (Radio Area Network) that includes sending (i) a conditional configuration associated with a base station operating in the RAN and (ii) conditions to be satisfied by the UE before applying the conditional configuration during a conditional procedure. The method also includes determining, after sending, that the UE will execute an immediate procedure related to the RAN. The method further includes providing the UE with an indication from the processing hardware to release the conditional configuration.

[0014] Another example implementation of these technologies is a method for communicating with a base station in a user equipment. The method includes receiving, by processing hardware, (i) a conditional configuration associated with a base station operating in the RAN and (ii) conditions to be satisfied by the UE before applying the conditional configuration during a conditional procedure. The method also includes, after receiving the conditional configuration, receiving from the RAN an instruction from the processing hardware that the UE release the conditional configuration. The method further includes, by the processing hardware, releasing the conditional configuration in response to the instruction. Attached Figure Description

[0015] Figure 1A and Figure 1B This is a block diagram of an example system in which the radio access network (RAN) and user equipment (UE) can implement the techniques of this disclosure to handle configurations associated with conditional handover (CHO), conditional secondary node addition / modification (CSAC), and / or conditional primary / secondary cell (CPAC) procedures;

[0016] Figure 1C This is a block diagram of an example base station, where centralized units (CUs) and distributed units (DUs) can be... Figure 1A or Figure 1B Operating within the system;

[0017] Figure 2 is a block diagram of an example protocol stack. Figure 1A or Figure 1B The UE can use this example protocol stack to communicate with Figure 1A or Figure 1B Communicate with base stations;

[0018] Figure 3A and Figure 3B This is a message passing diagram of an example scenario where the RAN includes the CHO conditional configuration in the "handover request" message to handle the release of the conditional configuration at the UE;

[0019] Figure 4 This is a message passing diagram of an example scenario where the RAN does not include the CHO conditional configuration in the "Handover Request" message to handle the release of the conditional configuration at the UE;

[0020] Figure 5 This is a message passing diagram of an example scenario where the RAN includes the CHO conditional configuration identifier in the RRC reconfiguration message to handle the release of the conditional configuration at the UE;

[0021] Figure 6A and Figure 6B This is a message passing diagram of an example scenario where the RAN includes the CSAC conditional configuration in the "handover request" message to handle the release of the conditional configuration at the UE;

[0022] Figure 7 This is a message passing diagram of an example scenario where the RAN does not include the CSAC conditional configuration in the "handover request" message to handle the release of the conditional configuration at the UE;

[0023] Figure 8 This is a message passing diagram of an example scenario where the RAN includes the identifier of the CSAC conditional configuration in the RRC reconfiguration message to handle the release of the conditional configuration at the UE.

[0024] Figure 9A and Figure 9B This is a message passing diagram of an example scenario in which the RAN includes the conditional configurations of CHO and CSAC in the "handover request" message to handle the release of two conditional configurations at the UE.

[0025] Figure 10 This is a message passing diagram of an example scenario where the RAN includes the CPAC's conditional configuration in the "SN Change requested" message to handle the release of the conditional configuration at the UE;

[0026] Figure 11 This is a message passing diagram of an example scenario where the RAN does not include the CPAC conditional configuration in the "Request SN Change" message to handle the release of the conditional configuration at the UE;

[0027] Figure 12 This is a flowchart depicting an example method implemented in a base station for handling the release of conditional configuration stored at the user equipment by including conditional configuration in the interface message when it is determined that a user equipment is configured to connect to a target base station;

[0028] Figure 13 This is a flowchart depicting an example method implemented in a base station for handling the release of conditional configurations stored at the user equipment upon receiving a "handover request" message or a "SNAddition Request" message;

[0029] Figure 14 This is a flowchart depicting an alternative example method implemented in a base station for handling the release of conditional configurations stored at the user equipment upon receiving a "handover request" message or a "SN add request" message;

[0030] Figure 15 This is a flowchart depicting an example method implemented in a base station for handling the release of conditional configuration stored at the user equipment by not including conditional configuration in the interface message when it is determined that a user equipment is configured to connect to a target base station;

[0031] Figure 16 This is a flowchart depicting an example method implemented in a base station for processing the release of conditional configuration stored at the user equipment by including an identifier of the conditional configuration in the interface message when it is determined that the user equipment is configured to connect to the target base station;

[0032] Figure 17 This is a flowchart depicting an example method implemented in the RAN for handling the release of conditional configurations stored at the user equipment; and

[0033] Figure 18 This is a flowchart depicting an example method implemented in a user device for handling the release of conditional configurations stored at the user device. Detailed Implementation

[0034] Figure 1A An example wireless communication system 100 is depicted, which can implement the conditional configuration management techniques of this disclosure. The wireless communication system 100 includes a UE 102 and base stations 104A, 106A, and 106B connected to a core network (CN) 110. Base stations 104A, 106A, and 106B can be any one or more suitable types of base stations, such as evolved Node B (eNB), next-generation eNB (ng-eNB), or 5G Node B (gNB). As a more specific example only, base station 104A can be an eNB or a gNB, and base stations 106A and 106B can be gNBs.

[0035] Base station 104A supports cell 124A, base station 106A supports cell 126A, and base station 106B supports cell 126B. Cell 124A partially overlaps with cells 126A and 126B, allowing UE 102 to be within range of communication with base station 104A while simultaneously being within range of communication with either base station 106A or 106B (or within range of detecting or measuring signals from both base stations 104A and 106A, etc.). This overlap allows UE 102 to hand over between cells (e.g., from cell 124A to cell 126A or 126B) before experiencing a radio link failure. Furthermore, this overlap enables various dual-connectivity (DC) scenarios discussed below. For example, UE 102 can communicate with base station 104A (operating as MN) and base station 106A (operating as SN) in DC mode, and when an SN change is completed, it can communicate with base station 104A (operating as MN) and base station 106B (operating as SN). More specifically, when UE 102 is in DC mode with base station 104A and base station 106A, base station 104A operates as MeNB, Mng-eNB, or MgNB, and base station 106A operates as SgNB or Sng-eNB. In implementations and scenarios where UE 102 is in SC mode with base station 104A but can operate in DC mode, base station 104A operates as MeNB, Mng-eNB, or MgNB, and base station 106A operates as a candidate SgNB (C-SgNB) or a candidate Sng-eNB (C-Sng-eNB). Although various scenarios are described below in which base station 104A operates as an MN and base station 106A (or 106B) operates as an SN or C-SN, in different scenarios, any one of base stations 104A, 106A, and 106B can typically operate as an MN, SN, or C-SN. Therefore, in some implementations, base stations 104A, 106A, and 106B can implement similar sets of functions and each support MN, SN, and C-SN operations.

[0036] In operation, UE 102 may use radio bearers (e.g., DRB or SRB) terminated at different times to MN (e.g., base station 104A) or SN (e.g., base station 106A). When communicating on the radio bearers in the uplink (from UE 102 to the base station) and / or downlink (from the base station to UE 102) directions, UE 102 may apply one or more security keys.

[0037] Base station 104A includes processing hardware 130, which may include one or more general-purpose processors (e.g., central processing unit (CPU)) and computer-readable memory storing machine-readable instructions that can be executed on the general-purpose processor(s) and / or dedicated processing unit(s). Figure 1A In the example implementation, the processing hardware 130 includes a base station RRC controller 132 configured to manage or control RRC procedures and RRC configurations. For example, the base station RRC controller 132 may be configured to support RRC messaging associated with instant and CHO procedures, instant and CSAC procedures, and / or support operations necessary when the base station 104A operates as an MN, as discussed below. Furthermore, in some implementations and / or scenarios, according to the various implementations discussed below, the base station RRC controller 132 may be responsible for (for UE 102 and...) Figure 1A (Several other UEs not shown in the text) handle the release of the conditional configuration.

[0038] Base station 106A includes processing hardware 140, which may include one or more general-purpose processors (e.g., CPUs) and computer-readable memory storing machine-readable instructions that can be executed on the general-purpose processors and / or dedicated processing units. Figure 1A In an example implementation, the processing hardware 140 includes a base station RRC controller 142 configured to manage or control RRC procedures and RRC configurations. For example, the base station RRC controller 142 may be configured to support RRC messaging associated with instant and CHO procedures, CPAC procedures, and / or support operations necessary when the base station 106A operates as an SN or candidate SN (C-SN), as discussed below. Furthermore, in some implementations and / or scenarios, according to the various implementations discussed below, the base station RRC controller 142 may be responsible for (for UE 102 and...) Figure 1A Several other UEs (not shown) handle the release of conditional configurations. Although Figure 1A Although not shown, base station 106B may include processing hardware similar to the processing hardware 140 of base station 106A.

[0039] UE 102 includes processing hardware 150, which may include one or more general-purpose processors (e.g., CPUs) and computer-readable memory storing machine-readable instructions that can be executed on the general-purpose processors and / or dedicated processing units. Figure 1AIn the example implementation, the processing hardware 150 includes a UE RRC controller 152 configured to manage or control RRC procedures and RRC configurations. For example, the UE RRC controller 152 may be configured to support RRC messaging associated with instant and CHO and / or SN add / modify procedures, and may also be responsible for releasing the conditional configuration of the UE 102 as needed, according to any of the implementations discussed below.

[0040] CN 110 can be either the Evolved Packet Core (EPC) 111 or the 5th Generation Core (5GC) 160, both of which are... Figure 1A As shown in the diagram. Base station 104A can be an eNB supporting an S1 interface for communication with EPC 111, an ng-eNB supporting an NG interface for communication with 5GC 160, or a gNB supporting an NR radio interface and an NG interface for communication with 5GC 160. Base station 106A can be an EN-DC gNB (en-gNB) with an S1 interface to EPC 111, an en-gNB not connected to EPC 111, a gNB supporting an NR radio interface and an NG interface to 5GC 160, or an ng-eNB supporting an EUTRA radio interface and an NG interface to 5GC 160. To exchange messages directly with each other during the various scenarios discussed below, base stations 104A, 106A, and 106B can support X2 or Xn interfaces.

[0041] In addition to other components, EPC 111 may include a Serving Gateway (S-GW) 112 and a Mobility Management Entity (MME) 114. S-GW 112 is typically configured to deliver user plane packets related to audio calls, video calls, internet traffic, etc., and MME 114 is typically configured to manage authentication, registration, paging, and other related functions. 5GC 160 includes a User Plane Function (UPF) 162 and Access and Mobility Management Function (AMF) 164 and / or Session Management Function (SMF) 166. UPF 162 is typically configured to deliver user plane packets related to audio calls, video calls, internet traffic, etc., AMF 164 is typically configured to manage authentication, registration, paging, and other related functions, and SMF 166 is typically configured to manage PDU sessions.

[0042] Generally, the wireless communication system 100 may include any suitable number of base stations supporting NR cells and / or EUTRA cells. More specifically, the EPC 111 or 5GC 160 may connect to any suitable number of base stations supporting NR cells and / or EUTRA cells. For example, see the reference below. Figure 1BIn the immediate and CHO scenarios discussed, additional base stations are considered. Although the examples below specifically involve particular CN types (EPC, 5GC) and RAT types (5G NR and EUTRA), in general, the techniques disclosed herein can also be applied to other suitable radio access and / or core network technologies, such as sixth-generation (6G) radio access and / or 6G core networks or 5G NR-6G DC.

[0043] As described above, the wireless communication system 100 can support various procedures (e.g., handover, SN addition, etc.) and operating modes (e.g., SC or DC). Example operations of various procedures that can be implemented in the wireless communication system 100 will now be described.

[0044] In some implementations, the wireless communication system 100 supports immediate handover between cells. For example, in one scenario, UE 102 initially connects to base station 104A, and base station 104A later performs an immediate handover procedure with base station 106A via an interface (e.g., X2 or Xn). In this scenario, base stations 104A and 106A operate as the source base station and the target base station, respectively. During the handover procedure, the source base station 104A sends a handover request message to the target base station 106A. In response, the target base station 106A includes an immediate handover command message in a handover request acknowledgment message and sends a handover request acknowledgment message to the source base station 104A. The source base station 104A then sends a handover command message to UE 102 in response to receiving the handover request acknowledgment message.

[0045] Upon receiving an immediate handover command message, UE 102 responds immediately to the immediate handover command by attempting to connect to the target base station 106A. To connect to the target base station 106A, UE 102 may execute a random access procedure with the target base station 106A, and then (after obtaining access to the control channel) send a handover completion message to the target base station 106A via the cell of base station 106A (i.e., in response to the immediate handover command).

[0046] In some implementations, the wireless communication system 100 also supports CHO (Choice of Handover) messages. For example, in one scenario, UE 102 initially connects to base station 104A, and base station 104A later performs a CHO procedure with base station 106A via an interface (e.g., X2 or Xn) to prepare for a potential handover of UE 102 to base station 106A. In this scenario, base stations 104A and 106A operate as the source base station and candidate base station, respectively. In the CHO procedure, the source base station 104A sends a handover request message to the candidate base station 106A. In response, the candidate base station 106A includes a CHO command message in its handover request response message and sends a handover request response message to the source base station 104A. The source base station 104A then sends a CHO command message to UE 102 in response to receiving the handover request response message.

[0047] Upon receiving a CHO command message, UE 102 does not immediately respond by attempting to connect to candidate base station 106A. Instead, UE 102 only connects to candidate base station 106A according to the CHO command message when UE 102 determines that the conditions for handover to candidate cell 126A are met. Base station 106A provides the configuration for candidate cell 126A in the CHO command message (i.e., the configuration that UE 102 can use to connect to base station 106A via candidate cell 126A).

[0048] Before the condition is met, UE 102 has not yet connected to candidate base station 106A. In other words, candidate base station 106A has not yet connected to and served UE 102. In some implementations, this condition may be that the signal strength / quality measured by UE 102 on candidate cell 126A of candidate base station 106A is "good" enough. For example, the condition can be met if one or more measurement results obtained by UE 102 (when performing measurements on candidate cell 126A) are higher than a threshold configured by source base station 104A, or higher than a predetermined or pre-configured threshold. If UE 102 determines that the condition is met, candidate base station 106A becomes target base station 106A for UE 102, and UE 102 attempts to connect to target base station 106A. To connect to target base station 106A, UE 102 may perform a random access procedure with target base station 106A, and then (after obtaining access to the control channel) send a handover completion message to target base station 106A via candidate cell 126A. After UE 102 successfully completes the random access procedure and / or sends the handover completion message, the target base station 106A becomes the source base station 106A of UE 102, and UE 102 begins to transmit data with the source base station 106A.

[0049] In some implementations, the wireless communication system 100 supports DC operation, including SN addition and SN change procedures. For example, in one scenario, after UE 102 connects to base station 104A, base station 104A can perform an immediate SN addition procedure to add base station 106A as a secondary node, thereby configuring UE 102 to operate in a DC with base stations 104A and 106A. At this time, base stations 104A and 106A operate as MN and SN, respectively. Later, while UE 102 is still in a DC with MN 104A and SN 106A, MN 104A can perform an immediate SN change procedure to change the SN of UE 102 from base station 106A (which may be referred to as the source SN or S-SN) to base station 106B (which may be referred to as the target SN or T-SN).

[0050] In other scenarios, when UE 102 is in a single connection (SC) with base station 104A, or when UE 102 is in a DC with base stations 104A and 106B, and before UE 102 connects to C-SN 106A, base station 104A may execute a CSAC procedure to configure base station 106A as a candidate SN (C-SN) for UE 102. In this case, base stations 104A and 106A operate as the MN and C-SN of UE 102, respectively. When UE 102 receives the configuration for C-SN 106A, UE 102 does not connect to C-SN 106A unless and until UE 102 detects that the corresponding condition is met. If UE 102 determines that the condition is met, then UE 102 connects to C-SN 106A, making C-SN 106A the SN 106A of UE 102.

[0051] In some implementations, the condition may be that the signal strength / quality measured by UE 102 on the candidate primary / secondary cell (C-PSCell) of C-SN 106A is sufficiently "good". For example, the condition can be met if one or more measurements obtained by UE 102 (when performing measurements on the C-PSCell) are higher than a threshold configured by MN 104A, or higher than a predetermined or pre-configured threshold. If UE 102 determines that the condition is met, UE 102 can perform a random access procedure with C-SN 106A to connect to C-SN 106A. Once UE 102 successfully completes the random access procedure, base station 106A becomes the SN of UE 102, and the C-PSCell (e.g., cell 126A) becomes the PSCell of UE 102. SN 106A can then begin transmitting data with UE 102.

[0052] Another scenario involves an immediate PSCell change. In this scenario, UE 102 is initially in communication with MN 104 (via the primary cell (PCell)) and SN 106A (via a PSCell different from cell 126A). Figure 1A In the DC (not shown in the diagram). SN106A can provide UE 102 with the configuration for C-PSCell 126A. If UE 102 is configured to a signaling radio bearer (SRB) (e.g., SRB3) that allows the exchange of RRC messages with SN 106A, then SN 106A can directly send the configuration for C-PSCell 126A to UE 102 via the SRB. Otherwise, SN 106A can send the configuration for C-PSCell 126A to UE 102 via MN 104A. In some scenarios, even if the UE is configured to an SRB, SN 106A can exchange RRC messages with UE 102 via MN 104A. For example, SN 106A can send the configuration in response to one or more measurement results received from UE 102 via the SRB or via MN 104, or in response to one or more measurement results obtained by SN 106A from measurements of signals received from UE 102. Upon receiving the configuration for C-PSCell 126A, UE 102 immediately connects to C-PSCell 126A, causing C-PSCell 126A to begin operating as the PSCell 126A of UE 102. In some implementations, UE 102 disconnects from the PSCell in order to connect to C-PSCell 126A.

[0053] Another scenario involves CPAC. Contrary to the immediate PSCell change discussed above, upon receiving the configuration for C-PSCell 126A, UE 102 does not immediately disconnect from the PSCell and attempt to connect to C-PSCell 126A. Instead, UE 102 does not connect to C-PSCell 126A until UE 102 determines that a certain condition has been met. When UE 102 determines that the condition has been met, UE 102 connects to C-PSCell 126A, causing C-PSCell 126A to begin operating as UE 102's PSCell 126A. In some implementations, UE 102 disconnects from the PSCell in order to connect to C-PSCell 126A.

[0054] In some scenarios, the condition associated with CSAC or conditional PSCell changes may be a signal strength / quality measured by UE 102 on the C-PSCell of C-SN106A exceeding a certain threshold or otherwise corresponding to an acceptable measurement. For example, UE 102 may determine that a condition is met when one or more measurements obtained by UE 102 on C-PSCell 126A are higher than a threshold configured by MN 104 or C-SN106A, or higher than a predetermined or pre-configured threshold. When UE 102 determines that such a condition is met, UE 102 may perform a random access procedure on C-PSCell 126A and with C-SN 106A to connect to C-SN 106A. Once UE 102 successfully completes the random access procedure on C-PSCell 126A, C-PSCell 126A becomes the PSCell 126A of UE 102. C-SN 106A can then begin transmitting data (user plane data and / or control plane data) to UE 102 via PSCell 126A.

[0055] In different configurations or scenarios of the wireless communication system 100, base station 104A can operate as a primary eNB (MeNB) or primary gNB (MgNB), and base station 106A or 106B can be implemented as a secondary gNB (SgNB) or candidate SgNB (C-SgNB). UE 102 can communicate with base station 104A and base station 106A or 106B via the same radio access technology (RAT) (such as EUTRA or NR) or via different RATs. If base station 104A is a MeNB and base station 106A is an SgNB, then UE 102 can be in an EUTRA-NR DC (EN-DC) with both a MeNB and an SgNB. In this scenario, MeNB 104A may or may not configure base station 106B as a C-SgNB for UE 102. When base station 104A is a MeNB and base station 106A is a C-SgNB for UE 102, UE 102 can be in an SC with the MeNB. In this scenario, MeNB 104 may or may not configure base station 106B as another C-SgNB for UE 102.

[0056] In some cases, a MeNB, SeNB, or C-SgNB can be implemented as an ng-eNB instead of an eNB. When base station 104A is the primary ng-eNB (Mng-eNB) and base station 106A is the SgNB, UE 102 can be in a next-generation (NG) EUTRA-NR DC (NGEN-DC) with both the Mng-eNB and the SgNB. In this scenario, MeNB 104A may or may not configure base station 106B as a C-SgNB for UE 102. When base station 104A is an Mng-NB and base station 106A is a C-SgNB for UE 102, UE 102 can be in a SeNB (Search Channel) with the Mng-eNB. In this scenario, Mng-eNB 104A may or may not configure base station 106B as another C-SgNB for UE 102.

[0057] When base station 104A is a MgNB and base station 106A is a SgNB, UE 102 can be in an NR-NR DC (NR-DC) with both the MgNB and SgNB. In this scenario, MgNB 104A may or may not configure base station 106B as another C-SgNB for UE 102. When base station 104A is a MgNB and base station 106A is a C-SgNB for UE 102, UE 102 can be in an SC with the MgNB. In this scenario, MgNB 104A may or may not configure base station 106B as another C-SgNB for UE 102.

[0058] When base station 104A is a MgNB and base station 106A is a secondary ng-eNB (Sng-eNB), UE 102 can be in an NR-EUTRA DC (NE-DC) with both the MgNB and the Sng-eNB. In this scenario, MgNB 104A may or may not configure base station 106B as a C-Sng-eNB for UE 102. When base station 104A is a MgNB and base station 106A is a candidate Sng-eNB (C-Sng-eNB) for UE 102, UE 102 can be in an SC with the MgNB. In this scenario, MgNB 104A may or may not configure base station 106B as another C-Sng-eNB for UE 102.

[0059] Figure 1B Another embodiment of the wireless communication system 100 is shown, wherein in addition to base stations 104A, 106A, and 106B, CN 110 is also connected to base station 104B. Base station 104B can be similar to the one described above. Figure 1ABase station 104A is discussed, and may also be similar to base stations 106A and / or 106B. Base station 104B may support X2 or Xn interfaces to connect to base stations 104A, 106A, and 106B. Base station 104B supports cell 124B. Cells 124B and 124A may partially overlap, allowing UE 102 to detect or measure signals from both base stations 104B and 104A when in a fixed position. In some implementations, base stations 104A, 104B, 106A, and / or 106B support Figure 1B One or more additional cells not shown. Base stations 104A, 104B, 106A, and 106B may support immediate handover, CHO, immediate SN add / change procedures, CSAC procedures, immediate PSCell change procedures, and / or CPAC procedures, such as those discussed above and those discussed in further detail below.

[0060] Figure 1C An exemplary distributed implementation of any one or more of base stations 104A, 104B, 106A, and 106B is depicted. In this implementation, base station 104A, 104B, 106A, or 106B includes a centralized unit (CU) 172 and one or more distributed units (DUs) 174. CU 172 includes processing hardware, such as one or more general-purpose processors (e.g., CPUs), and a computer-readable memory storing machine-readable instructions executable on the general-purpose processor(s) and / or dedicated processing units. For example, CU 172 may include... Figure 1A The processing hardware 130 or 140 may include a base station RRC controller (e.g., controller 142) configured to manage or control one or more RRC configurations and / or RRC procedures when the base station (e.g., base station 106A) operates as an SN or a candidate SN (C-SN).

[0061] Each DU 174 also includes processing hardware that may include one or more general-purpose processors (e.g., CPUs) and computer-readable memory storing machine-readable instructions executable on one or more general-purpose processors and / or dedicated processing units. For example, the processing hardware may include a Media Access Control (MAC) controller configured to manage or control one or more MAC operations or procedures (e.g., random access procedures), and an RLC controller configured to manage or control one or more Radio Link Control (RLC) operations or procedures when the base station (e.g., base station 106A) operates as an MN, SN, or C-SN. The processing hardware may also include a physical layer controller configured to manage or control one or more physical layer operations or procedures.

[0062] Figure 2 illustrates a simplified example radio protocol stack 200, which UE 102 can use to communicate with an eNB / ng-eNB or gNB (e.g., one or more of base stations 104A, 104B, 106A, and 106B). In the example stack 200, the EUTRA physical layer (PHY) 202A provides a transport channel to the EUTRA MAC sublayer 204A, which in turn provides a logical channel to the EUTRA RLC sublayer 206A. The EUTRA RLC sublayer 206A then provides an RLC channel to the EUTRA PDCP sublayer 208, and in some cases, to the NR PDCP sublayer 210. Similarly, the NR PHY 202B provides a transport channel to the NR MAC sublayer 204B, which in turn provides a logical channel to the NR RLC sublayer 206B. The NR RLC sublayer 206B then provides RLC channels to the NR PDCP sublayer 210. In some implementations, the UE 102 supports both the EUTRA stack and the NR stack as shown in FIG2 to support handover between the EUTRA and NR base stations and / or support DC on the EUTRA and NR interfaces. Furthermore, as shown in FIG2, the UE 102 may support the layering of the NR PDCP sublayer 210 on the EUTRA RLC sublayer 206A.

[0063] EUTRA PDCP sublayer 208 and NR PDCP sublayer 210 receive packets that can be referred to as Service Data Units (SDUs) (e.g., from Internet Protocol (IP) layers directly or indirectly layered on PDCP layers 208 or 210), and (e.g., to RLC layers 206A or 206B) output packets that can be referred to as Protocol Data Units (PDUs). Except where the difference between SDU and PDU is relevant, for simplicity, this disclosure refers to both SDU and PDU as "packets".

[0064] For example, on the control plane, EUTRA PDCP sublayer 208 and NR PDCP sublayer 210 can provide SRBs to exchange RRC messages. On the user plane, EUTRA PDCP sublayer 208 and NR PDCP sublayer 210 can provide DRBs to support data exchange.

[0065] In scenarios where UE 102 operates in an EUTRA / NR DC (EN-DC) with base station 104A operating as a MeNB and base station 106A operating as an SgNB, wireless communication system 100 can provide UE 102 with an MN termination bearer using EUTRA PDCP sublayer 208 or an MN termination bearer using NR PDCP sublayer 210. In various scenarios, wireless communication system 100 can also provide UE 102 with an SN termination bearer using only NR PDCP sublayer 210. The MN termination bearer can be an MCG bearer or a separate bearer. The SN termination bearer can be an SCG bearer or a separate bearer. The MN termination bearer can be an SRB (e.g., SRB1 or SRB2) or a DRB. The SN termination bearer can be an SRB or a DRB.

[0066] Figure 3 to Figure 11 The message sequences between UE 102 and various base stations (including base stations 104A, 106A and / or 106B) of the RAN are shown for various scenarios and implementations related to conditional configuration processing.

[0067] Specifically, Figure 3 (i.e., Figure 3A and Figure 3B )to Figure 5 This corresponds to a conditional scenario in which the RAN of the wireless communication system 100 initially provides the conditional configuration of the CHO to the UE 102 and later determines to release the conditional configuration stored at the UE 102 during the immediate handover procedure. Figure 6 (i.e., Figure 6A and Figure 6B )arrive Figure 8 This corresponds to a scenario where the RAN of the wireless communication system 100 initially provides the CSAC conditional configuration to the UE 102 and later determines to release the conditional configuration stored at the UE 102 during the immediate handover procedure. Figure 9 (i.e., Figure 9A and Figure 9B This corresponds to a scenario in which the RAN of the wireless communication system 100 initially provides the UE 102 with a first conditional configuration of CHO and a second conditional configuration of CSAC, and later determines the scenario in which the first and second conditional configurations stored at the UE 102 are released during the immediate handover procedure. Figure 10 and Figure 11 This corresponds to a scenario in which the RAN of the wireless communication system 100 initially provides the CPAC conditional configuration to the UE 102 and later determines to release the conditional configuration stored at the UE 102 during an instant SN add / change procedure.

[0068] First refer to Figures 3A to 5In the scenario shown, the RAN initially provides the CHO conditional configuration to the UE 102 and later determines to release the conditional configuration stored at the UE 102 during the immediate handover procedure.

[0069] according to Figure 3A In scenario 300A, base station 104A operates as the source MN (S-MN) of UE 102, base station 106B operates as the candidate MN (C-MN) of UE 102, and base station 104B operates as the target MN (T-MN) of UE 102.

[0070] Initially, UE 102 transmits 302A data (e.g., uplink (UL) data PDU and / or downlink (DL) data PDU) via the primary cell (e.g., PCell 124A) and S-MN 104A using the S-MN configuration.

[0071] At a certain point, when it is determined that a CHO procedure should be executed to enable communication between C-MN 106B and UE 102, S-MN 104A, for example, requests conditional configuration (e.g., C-MN configuration) from C-MN 106B to provide to UE 102 in response to the detection of a suitable event. For example, determination 304A may occur directly in response to S-MN 104A receiving one or more measurements from UE 102 (e.g., via an SRB established between UE 102 and S-MN 104A or via a physical control channel) that are higher than (or lower than) one or more predetermined thresholds, or in response to S-MN 104A having analyzed measurements received from UE 102 on signals, control channels, or data channels. In another example, a suitable event could be that UE 102 is moving towards C-MN 106B.

[0072] After determining the 304A request for C-MN configuration, S-MN 104A sends a 306A handover request message to C-MN 106B. In response to the handover request message, C-MN 106B generates a 308A C-MN configuration, which includes information enabling UE 102 to communicate with C-MN 106B via a candidate cell (which may be referred to as a candidate PCell (C-PCell)). C-MN 106B includes the C-MN configuration in its handover request response message to UE 102 and subsequently sends a 310A handover request response message to S-MN 104A in response to the handover request message. In some implementations, C-MN 106B may include a CHO command in the handover request response message instead of the C-MN configuration. In other cases, C-MN 106B may include the C-MN configuration in the CHO command and the CHO command in the handover request response message.

[0073] S-MN 104A sends an RRC reconfiguration message (312A) including the C-MN configuration to UE 102. UE 102 may optionally respond to receiving the RRC reconfiguration message by sending an RRC reconfiguration completion message (314A) to S-MN 104A. In some implementations, S-MN 104A includes conditions (or conditions) in the C-MN configuration or RRC reconfiguration message for UE 102 to detect, such that if the conditions are met, UE 102 can communicate with C-MN 106B. S-MN 104A may include the C-MN configuration in the conditional configuration field or information element (IE) of the RRC reconfiguration message. S-MN 104A may also include a configuration identifier / identifier (ID) associated with the C-MN configuration in the conditional configuration field / IE, enabling UE 102 to recognize and store the C-MN configuration. S-MN 104A may assign a configuration ID or receive a configuration ID from C-MN 106B. Events 302A, 304A, 306A, 308A, 310A, 312A, and 314A are in Figure 3A In China, they are collectively referred to as CHO Configuration Program 360A.

[0074] Later, before UE 102 determines that the conditions for handover to C-MN 106B are met, S-MN 104A, for example, in response to detecting a suitable event, determines 316A to perform an immediate handover procedure with T-MN 104B, enabling communication between T-MN 104B and UE 102. For example, determination 316A may occur in response to S-MN 104A receiving one or more measurement results from UE 102 that are higher than (or lower than) one or more predetermined thresholds, or in response to S-MN 104A having analyzed measurements received from UE 102 on signals, control channels, or data channels. In another example, a suitable event could be that UE 102 is moving towards T-MN 104B.

[0075] In response to this determination, S-MN 104A sends a 318A handover request message to T-MN 104B via an interface (e.g., the X2 / Xn interface) to request immediate handover of UE 102. The handover request message includes the S-MN configuration, making T-MN 104B aware of any pre-existing configurations known to UE 102 (e.g., the S-MN configuration) to determine any additional configurations that UE 102 may still require when performing the immediate handover procedure from S-MN 104A to T-MN 104B. Furthermore, because T-MN 104B is not aware of the C-MN configuration stored at UE 102, S-MN 104A also includes the C-MN configuration in the handover request message, making T-MN 104B aware of the C-MN configuration stored at UE 102 upon receiving the handover request message. In some implementations, S-MN 104A may include a configuration ID associated with the C-MN configuration in the handover request message. In some implementations, the S-MN 104A may include the C-MN configuration and S-MN configuration in the HandoverPreparationInfo IE (or RRC inter-node message), and include the HandoverPreparationInfo IE in the handover request message. In other implementations, the S-MN 104A may include the C-MN configuration and S-MN configuration in an RRC message (e.g., an RRC reconfiguration message), include the RRC message in the HandoverPreparationInfo IE, and then include the HandoverPreparationInfo IE in the handover request message. In some implementations, the S-MN 104A may include a configuration ID associated with the C-MN configuration in either the RRC message or the HandoverPreparationInfo IE.

[0076] Upon identifying the C-MN configuration indicated in the handover request message, T-MN 104B determines 320A to release the C-MN configuration stored at UE 102. In response to this determination, T-MN 104B generates a handover command message including the C-MN configuration to release field / IE. The handover command message also includes one or more random access configurations required for UE 102 to hand over to T-MN 104B. In some implementations, the handover command message may have additional fields, such as mobility fields (e.g., a mobilityControlInfo field or a reconfigurationWithSync field). Mobility fields may include some or all of the random access configurations. T-MN 104B then sends a 322A handover request response message, including the handover command message, to S-MN 104A in response to receiving the 318A handover request message. In some implementations, the T-MN 104B may include the configuration ID associated with the C-MN configuration in the C-MN configuration field / IE to be released.

[0077] In embodiments where S-MN 104A does not have a direct interface with T-MN 104B, S-MN 104A, CN 110, and T-MN 104B can jointly execute the CN procedure. To initiate the CN procedure, S-MN 104A can send a handover required message containing the content of a handover request message to CN 110 (e.g., MME 114 or AMF 164) instead of sending the 318A handover request message. CN 110 then includes the handover request message content in a handover request message generated by CN 110. CN 110 sends the generated handover request message to T-MN 104B. T-MN 104B performs action 320A upon receiving the handover request message from CN 110. Then T-MN 104B generates a handover request response message including the aforementioned handover command message, and sends the handover request response message to CN 110 in response to the handover request message received from CN 110. CN 110, in response to the request handover message, sends a handover confirmation message including the handover command message to S-MN 104A, thereby terminating the CN procedure.

[0078] Upon receiving a handover command message (i.e., from CN 110 or T-MN 104B), S-MN 104A sends a 324A handover command message to UE 102, causing UE 102 to release the C-MN configuration stored in 326A. In one implementation, UE 102 can identify the configuration ID included in the C-MN configuration field / IE to be released, and release the C-MN configuration associated with that configuration ID. In some implementations, if UE 102 can identify the configuration ID included in the C-MN configuration field / IE to be released, UE 102 can also release the conditions associated with the C-MN configuration. In other implementations, if UE 102 identifies the configuration ID included in the C-MN configuration field / IE to be released, UE 102 releases the condition configuration field / IE that includes the C-MN configuration and the conditions. In some implementations, this condition may be associated with at least one measurement configuration (e.g., MeasConfig IE) configured by S-MN 104A to UE 102 before sending a handover command message to UE 102. At least one measurement configuration is associated with a measurement identifier (e.g., MeasId IE). In some implementations, if UE 102 identifies a configuration ID included in the C-MN configuration field / IE to be released, UE 102 may release at least one measurement configuration. In other implementations, if UE 102 identifies a configuration ID included in the C-MN configuration field / IE to be released, UE 102 does not release at least one measurement configuration. Instead, if UE 102 identifies a measurement identifier (associated with a measurement configuration in at least one measurement configuration) in the measurement identity toremove list field / IE (e.g., measIdToRemoveList) in the handover command message, UE 102 releases that measurement configuration. The T-MN 104B can determine the release measurement configuration in response to the determination of the 320A release C-MN configuration, and as a result, include the list field of measurement identifiers to be removed / IE in the handover command message.

[0079] UE 102 also performs an immediate handover with T-MN 104B in response to the handover command message. During the handover, UE 102 performs a 328A random access procedure via T-PCell 124B and T-MN 104B, for example, using one or more random access configurations in the handover command message. During or after the random access procedure, UE 102 sends a 330A handover complete message. If UE 102 successfully completes the random access procedure, UE 102 transmits 332A control signals and data via PCell 124B and MN 104B.

[0080] In some scenarios, in response to S-MN 104A determining that 316A is performing an immediate handover or receiving a 322 handover request response message, S-MN 104A can send a 334A handover cancel message to C-MN 106B, causing C-MN 106B to release its C-MN configuration. Therefore, C-MN 106B does not need to waste its resources to maintain the C-MN configuration, because UE 102 is no longer configured to use the C-MN configuration to communicate with C-MN 106B.

[0081] In some implementations, if the S-MN 104A is an eNB or a next-generation eNB (ng-eNB), the RRC reconfiguration message and the RRC reconfiguration complete message can be respectively an RRCConnectionReconfiguration message and an RRCConnectionReconfigurationComplete message. If the S-MN 104A is a gNB, the RRC reconfiguration message and the RRC reconfiguration complete message can be respectively an RRCReconfiguration message and an RRCReconfigurationComplete message.

[0082] In some implementations, if S-MN 104A is an eNB or ng-eNB, the handover command message and the handover completion message can be RRCConnectionReconfiguration and RRCConnectionReconfigurationComplete messages, respectively. If S-MN 104A is a gNB, the handover command message and the handover completion message can be RRCReconfiguration and RRCReconfigurationComplete messages, respectively.

[0083] In some implementations, the C-MN configuration can be a complete and self-contained configuration (i.e., a full configuration). The C-MN configuration may include a full configuration indication (information element (IE) or field) indicating that the C-MN configuration is a full configuration. If UE 102 is connected to C-MN 106B, UE 102 can use the C-MN configuration (i.e., the full configuration) to communicate with C-MN 106B without referencing the S-MN configuration. In other implementations, the C-MN configuration is an incremental configuration because the C-MN configuration may include one or more configurations "above" the S-MN configuration (i.e., one or more configurations not included in the S-MN configuration). If UE 102 is connected to C-MN 106B, UE 102 can use the C-MN configuration (i.e., the incremental configuration) along with the S-MN configuration to communicate with C-MN 106B.

[0084] In some implementations, the C-MN configuration may include multiple configuration parameters for UE 102 to communicate with C-MN 106B via C-PCell 126B. These multiple configuration parameters may configure radio resources for UE 102 to communicate with C-MN 106B via C-PCell 126B and zero or more candidate secondary cells (C-SCells) of C-MN 106B. The multiple configuration parameters may configure zero or more radio bearers. The one or more radio bearers may include SRBs and / or / multiple DRBs. Similarly, the S-MN configuration may include multiple configuration parameters for UE 102 to communicate with S-MN 104A via PCell 124A and zero or more secondary cells (SCells) of S-MN 104A. These multiple configuration parameters may configure radio resources for UE 102 to communicate with S-MN 104A via PCell 124A and zero or more SCells of S-MN 104A. Multiple configuration parameters can be configured to specify zero, one, or more radio bearers. One or more radio bearers may include SRBs and / or (multiple) DRBs.

[0085] In some implementations, C-MN configuration may include configuring the CellGroupConfig IE for C-PCell 126B and may configure zero or one C-SCell for C-MN 106B. In one implementation, C-MN configuration may be an RRCReconfiguration message, RRCReconfiguration-IE, or CellGroupConfig IE conforming to 3GPP TS 38.331. A complete configuration indication may be a field or IE conforming to 3GPP TS 38.331. In other implementations, C-MN configuration may be an RRCConnectionReconfiguration message or RRCConnectionReconfiguration-IE conforming to 3GPP TS 36.331. A complete configuration indication may be a field or IE conforming to 3GPP TS 36.331. In another implementation, the C-MN configuration may be included in a conditional configuration field or information element (IE), and the conditional configuration field / IE may also be included in an RRCReconfiguration message conforming to 3GPP TS 38.331, an RRCReconfiguration-IE, or a CellGroupConfig IE. In other implementations, the C-MN configuration may be an RRCConnectionReconfiguration message conforming to 3GPP TS 36.331 or an RRCConnectionReconfiguration-IE. The conditional configuration field / IE may be a CHO-Config (CHO configuration) for NR configuration (e.g., CHO-Config-r16) or a ConditionalReconfiguration (Conditional Reconfiguration-r16) for EUTRA configuration. The conditional configuration field / IE may include at least a list of conditional configurations to be removed (e.g., cho-ConfigToRemoveList or condReconfigurationToRemoveList), a list of conditional configurations to be added or modified (e.g., cho-ConfigToAddModList or condReconfigurationToAddModList), and an attemptCHO field / IE.The list of conditional configurations to be added or modified can contain configuration IDs (e.g., cho-ConfigId-r16 or condReconfigurationId-r16), execution conditions (e.g., cho-ExecutionCond-r16 or triggerCondition-r16), and C-MN configurations (i.e., the configurations to be applied when the execution conditions are met or triggered (e.g., cho-RRCReconfig-r16, condReconfigurationToApply-r16)). In one implementation, the C-MN configuration field / IE to be released can be a list of conditional configurations to be removed, and it can consist of a list of configuration IDs.

[0086] In some implementations, the S-MN configuration may include configuring the CellGroupConfig IE for PCell 124A, and may configure zero or one or more SCells for S-MN 104A. In one implementation, the S-MN configuration may be an RRCReconfiguration message, RRCReconfiguration-IE, or CellGroupConfig IE conforming to 3GPP TS 38.331. In other implementations, the S-MN configuration may be an RRCConnectionReconfiguration message or RRCConnectionReconfiguration-IE conforming to 3GPP TS 36.331.

[0087] In some implementations, C-MN 106B may include CU 172 and one or more DU 174, such as Figure 1C As shown. DU 174 can generate a C-MN configuration or at least a portion of a C-MN configuration and send the C-MN configuration (or a portion) to CU 172. If DU 174 generates only a portion of the C-MN configuration, CU 172 can generate the remaining portion of the C-MN configuration. In some implementations, T-MN 106B may include CU 172 and one or more DU 174s, such as Figure 1CAs shown. DU 174 can generate some configurations in the handover command and send these configurations to CU 172. For example, the configurations generated by DU 174 may include one or more random access configurations, physical downlink control channel (PDCCH) configurations, physical uplink control channel (PUCCH) configurations, etc. CU 172 can generate other configurations (e.g., SRB configuration, DRB configuration, security configuration, and / or measurement configuration) in the handover command. In other embodiments, DU 174 can generate the CellGroupConfig IE in the handover command, and CU 172 can generate the RadioBearerConfig IE.

[0088] exist Figure 3B In scenario 300B, similar to event 360A, UE 102, S-MN 104A and C-MN 106B jointly execute the 360B conditional handover configuration procedure.

[0089] Subsequently, and before UE 102 determines that the conditions for handover to C-MN 106B are met, similar to events 316A and 318A respectively, S-MN 104A determines that 316B performs an immediate handover procedure with T-MN 104B, and then sends a 318B handover request message to T-MN 104B via an interface (e.g., the X2 / Xn interface) to request immediate handover from UE 102.

[0090] exist Figure 3A In this scenario, T-MN 104B identifies the C-MN configuration indicated in the handover request message to determine whether 320A releases the C-MN configuration stored at UE 102. Figure 3B In this scenario, the T-MN 104B ignores (or discards) the C-MN configuration indicated in the 320B handover request message. Therefore, in Figure 3A In the process, T-MN 104B generates a handover command message that includes the C-MN configuration field / IE to be released, while... Figure 3B In this process, T-MN 104B generates a handover command message that does not include the C-MN configuration field / IE to be released. T-MN 104B then responds to receiving the 318B handover request message by sending a 322B handover request response message to S-MN 104A, which includes the handover command message.

[0091] In implementations where S-MN 104A does not have a direct interface with T-MN 104B, S-MN 104A, CN 110, and T-MN 104B can jointly execute a CN program similar to that described above for scenario 300A.

[0092] Upon receiving a handover command message (i.e., from CN 110 or T-MN 104B), S-MN 104A sends a 324B handover command message to UE 102, causing UE 102 to release the C-MN configuration stored in 326B. In one embodiment, UE 102 is configured to release the stored C-MN configuration when it is recognized that the handover command message does not include the C-MN configuration field / IE to be released. In some embodiments, UE 102 may also be configured to release the conditions associated with the stored C-MN configuration when it is recognized that the handover command message does not include the C-MN configuration field / IE to be released. In other embodiments, UE 102 releases a condition configuration field / IE that includes the C-MN configuration and the conditions when it is recognized that the handover command message does not include the C-MN configuration field / IE to be released. In some embodiments, the condition may be associated with at least one measurement configuration (e.g., MeasConfig IE) configured to UE 102 by S-MN 104A before sending the handover command message to UE 102. At least one measurement configuration is associated with a measurement identifier (e.g., MeasId IE). In some implementations, UE 102 may release at least one measurement configuration if it recognizes that the handover command message does not include the C-MN configuration field / IE to be released. In other implementations, UE 102 does not release at least one measurement configuration if it recognizes that the handover command message does not include the C-MN configuration field / IE to be released. Instead, if UE 102 recognizes a measurement identifier (associated with a measurement configuration in at least one measurement configuration) in the list of measurement identifiers to be removed field / IE (e.g., measIdToRemoveList) in the handover command message, then UE 102 releases the measurement configuration. That is, T-MN 104B determines to release the measurement configuration in response to ignoring the 320B C-MN configuration.

[0093] UE 102 then performs immediate handover with T-MN 104B by executing a random access procedure (328B) with T-MN 104B via T-PCell 124B, sending a 330B handover completion message during or after the random access procedure, and transmitting 332B control signals and data with MN 104B via PCell 124B if UE 102 successfully completes the random access procedure (similar to events 328A, 330A, and 332A, respectively). In some scenarios, similar to event 334A, S-MN 104A can send a 334B handover cancellation message to C-MN 106B, causing C-MN 106B to release the C-MN configuration.

[0094] exist Figure 4In scenario 400, similar to event 360A, UE 102, S-MN 104A and C-MN 106B jointly execute the 460 conditional handover configuration procedure.

[0095] Later, and before UE 102 determines that the conditions for handover to C-MN 106B are met, similar to event 316A, S-MN 104A determines 416 to perform an immediate handover procedure with T-MN 104B. Figure 3A In this scenario, S-MN 104A sends a 318A handover request message, including S-MN configuration and C-MN configuration, to T-MN 104B, while... Figure 4 In this scenario, S-MN 104A generates an RRC message (e.g., an RRC reconfiguration message) that includes S-MN configuration but not C-MN configuration (417), and then sends a handover request message (418) including the RRC message to T-MN 104B. In some implementations, S-MN 104A may include the RRC message in the HandoverPreparationInfo IE and include the HandoverPreparationInfo IE in the handover request message.

[0096] Therefore, in Figure 3A In the process, T-MN 104B generates a handover command message including the C-MN configuration field / IE to be released, and in response to receiving the 318 handover request message, sends a 322A handover request response message including the handover command message to S-MN 104A. Figure 4 In this process, T-MN 104B generates a handover command message that does not include the C-MN configuration field / IE to be released, and in response to receiving the 418 handover request message, sends a 422 handover request response message including the handover command message to S-MN 104A.

[0097] When S-MN 104A does not have a direct interface with T-MN 104B, S-MN 104A, CN 110 and T-MN 104B can jointly execute a CN program similar to that described above for scenario 300A.

[0098] Upon receiving a handover command message (i.e., from CN 110 or T-MN 104B), similar to event 326B, S-MN104A sends a 424 handover command message to UE 102, causing UE 102 to release the C-MN configuration stored in 426.

[0099] UE 102 then performs immediate handover with T-MN 104B by executing the random access procedure 428 with T-MN 104B via T-PCell 124B, sending a handover completion message 430 during or after the random access procedure, and transmitting control signals and data 432 with MN 104B via PCell 124B if UE 102 successfully completes the random access procedure (similar to events 328B, 330B, and 332B, respectively). In some scenarios, similar to event 334B, S-MN 104A can send a handover cancellation message 434 to C-MN 106B, causing C-MN 106B to release the C-MN configuration.

[0100] exist Figure 5 In scenario 500, similar to event 360A, UE 102, S-MN 104A and C-MN 106B jointly execute the 560 conditional handover configuration procedure.

[0101] Later, and before UE 102 determines that the conditions for handover to C-MN 106B are met, similar to event 416, S-MN 104A determines 516 to perform the immediate handover procedure with T-MN 104B. Figure 4 In this scenario, S-MN 104A and T-MN104B jointly execute immediate handover events 417, 418, 422, and 424 to cause UE 102 to release the C-MN configuration stored in 426. Figure 5In this scenario, before initiating an immediate handover procedure, S-MN 104A sends an RRC reconfiguration message (517) to UE 102, including the C-MN configuration field / IE to be released, causing UE 102 to release the C-MN configuration stored (526). In response to receiving the RRC reconfiguration message, UE 102 releases the C-MN configuration (526) and sends an RRC reconfiguration complete message (519) back to S-MN 104A. In one implementation, UE 102 can identify the configuration ID included in the C-MN configuration field / IE to be released, and release the C-MN configuration associated with that configuration ID. In some implementations, if UE 102 identifies the configuration ID included in the C-MN configuration field / IE to be released, UE 102 can also release the conditions associated with the C-MN configuration. In other implementations, if UE 102 identifies the configuration ID included in the C-MN configuration field / IE to be released, UE 102 releases the condition configuration field / IE that includes the C-MN configuration and the conditions. In some implementations, this condition may be associated with at least one measurement configuration (e.g., MeasConfig IE) configured by S-MN 104A to UE 102 before sending an RRC reconfiguration message to UE 102. At least one measurement configuration is associated with a measurement identifier (e.g., MeasId IE). In some implementations, UE 102 may release at least one measurement configuration if it identifies a configuration ID included in the C-MN configuration field / IE to be released. In other implementations, UE 102 does not release at least one measurement configuration if it identifies a configuration ID included in the C-MN configuration field / IE to be released. Instead, UE 102 releases the measurement configuration if it identifies a measurement identifier (associated with a measurement configuration in at least one measurement configuration) in the list of measurement identifiers to be removed field / IE (e.g., measIdToRemoveList) in the RRC reconfiguration message. The S-MN 104A can determine the release of measurement configurations in response to determining 516 to perform immediate handover, and as a result, include the list field of measurement identifiers to be removed / IE in the RRC reconfiguration message.

[0102] Next, similar to event 418, S-MN 104A initiates an immediate handover procedure by sending a handover request message 518, including the S-MN configuration, to T-MN 104B to request immediate handover of UE 102. In some implementations, S-MN 104A may include the S-MN configuration in the HandoverPreparationInfo IE and also include the HandoverPreparationInfo IE in the handover request message. In some implementations, S-MN 104A may include the S-MN configuration in an RRC message (e.g., an RRC reconfiguration message) within the HandoverPreparationInfo IE and also include the HandoverPreparationInfo IE in the handover request message.

[0103] Similar to event 422, in response to receiving the handover request message, T-MN 104B generates a handover command message that does not include the C-MN configuration field / IE to be released, and sends a handover request response message 522, including the handover command message, to S-MN 104A. In other embodiments, event 518 may occur before events 519 or 517, such that event 518 may not respond to event 519.

[0104] In implementations where S-MN 104A does not have a direct interface with T-MN 104B, S-MN 104A, CN 110, and T-MN 104B can jointly execute a CN program similar to that described above for scenario 300A.

[0105] Next, upon receiving a handover command message (i.e., from CN 110 or T-MN 104B), S-MN 104A sends a 524 handover command message to UE 102. UE 102 then performs immediate handover with T-MN 104B by executing a 528 random access procedure with T-MN 104B via T-PCell 124B, sending a 530 handover completion message during or after the random access procedure, and, if UE 102 successfully completes the random access procedure, transmitting 532 control signals and data with MN 104B via PCell 124B (similar to events 428, 430, and 432, respectively). In some scenarios, similar to event 434, S-MN 104A can send a 534 handover cancellation message to C-MN 106B, causing C-MN 106B to release the C-MN configuration.

[0106] refer to Figures 6A to 8In these scenarios, the RAN initially provides the CSAC conditional configuration to the UE 102 and later determines to release the conditional configuration stored at the UE 102 during the immediate handover procedure.

[0107] refer to Figure 6A In scenario 600A, base station 104A operates as the S-MN of UE 102, base station 106A operates as the SN of UE 102, base station 106B operates as the C-SN of UE 102, and base station 104B operates as the T-MN of UE 102.

[0108] Initially, UE 102 in the SC transmits 602A data (e.g., UL data PDU and / or DL ​​data PDU) via the primary cell (e.g., PCell 124A) and S-MN104A using the S-MN configuration. Alternatively, UE 102 in the DC transmits 602A data via PCell 124A and S-MN 104A using the S-MN configuration, and transmits 602A data via PSCell 126A and SN 106A using the SN configuration.

[0109] Later, when determining to execute the CSAC procedure that enables communication between C-SN 106B and UE 102, S-MN 104A, for example blindly or in response to detecting a suitable event, determines 604A to request conditional configurations (e.g., C-SN configurations) provided to UE 102 from C-SN 106B. For example, determination 604A may occur in response to S-MN 104A receiving one or more measurements above (or below) one or more predetermined thresholds directly from UE 102 (e.g., via an SRB established between UE 102 and S-MN 104A or via a physical control channel), or in response to S-MN 104A having analyzed measurements received from UE 102 on signals, control channels, or data channels. In another example, a suitable event could be that UE 102 is moving towards C-SN 106B.

[0110] After determining the 604A request for C-SN configuration, S-MN 104A sends a 606A SN request message to C-SN 106B. In response to the SN request message, C-SN 106B generates a 608A C-SN configuration, which includes information enabling UE 102 to communicate with C-SN 106B via a candidate cell (which may be referred to as a candidate PSCell (C-PSCell)). C-SN 106B includes the C-SN configuration in its SN request response message to UE 102, and subsequently sends a 610A SN request response message to S-MN 104A in response to the SN request message. In some implementations, the SN request message may be an SN add request or an SN modify request message, and the SN request response message may be an SN add request response or an SN modify request response message.

[0111] S-MN 104A sends an RRC reconfiguration message (612A) including the C-SN configuration to UE 102. UE 102 may optionally respond to receiving the RRC reconfiguration message by sending an RRC reconfiguration completion message (614A) to S-MN 104A. In some implementations, S-MN 104A may include the C-SN configuration message in the RRC container message and then include the RRC container message in the RRC reconfiguration message. In some implementations, S-MN 104A includes the RRC container message in the C-SN configuration or includes conditions (or conditions) for UE 102 to detect in the RRC reconfiguration message, such that if the conditions are met, UE 102 can communicate with C-SN 106B. S-MN 104A may include the C-SN configuration in the conditional configuration field or IE of the RRC reconfiguration message. S-MN 104A may also include a configuration ID associated with the C-SN configuration in the conditional configuration field / IE, enabling UE 102 to identify and store the C-SN configuration. S-MN 104A can assign configuration IDs or receive configuration IDs from C-SN 106B. Events 602A, 604A, 606A, 608A, 610A, 612A, and 614A are... Figure 6A In general, they are referred to as CSAC Configuration Program 670A.

[0112] Later, and before UE 102 determines that the conditions for condition SN change are met, S-MN 104A, either blindly or in response to detecting a suitable event, determines 616A to perform an immediate handover procedure with T-MN 104B to enable communication between T-MN 104B and UE 102. For example, determination 616A may occur in response to S-MN 104A receiving one or more measurements from UE 102 that are above (or below) one or more predetermined thresholds, or in response to S-MN 104A having analyzed measurements received from UE 102 on signals, control channels, or data channels. In another example, a suitable event could be that UE 102 is moving towards T-MN 104B.

[0113] In response to this determination, S-MN 104A sends a 618A handover request message to T-MN 104B via an interface (e.g., the X2 / Xn interface) to request immediate handover of UE 102. The handover request message includes the S-MN configuration, making T-MN 104B aware of any pre-existing configurations known to UE 102 (e.g., the S-MN configuration) to determine the additional configuration(s) still required by UE 102 when performing the immediate handover procedure from S-MN 104A to T-MN 104B. Furthermore, because T-MN 104B is unaware of the C-SN configuration stored at UE 102, S-MN 104A also includes the C-SN configuration in the handover request message, making T-MN 104B aware of the C-SN configuration stored at UE 102 upon receiving the handover request message. In some implementations, S-MN 104A may include a configuration ID associated with the C-SN configuration in the handover request message. In some implementations, the S-MN 104A may include the C-SN configuration and S-MN configuration in the HandoverPreparationInfo IE (or RRC inter-node message), and also include the HandoverPreparationInfo IE in the handover request message. In other implementations, the S-MN 104A may include the C-SN configuration and S-MN configuration in an RRC message (e.g., an RRC reconfiguration message), include the RRC message in the HandoverPreparationInfo IE, and then include the HandoverPreparationInfo IE in the handover request message. In some implementations, the S-MN 104A may include a configuration ID associated with the C-SN configuration in either the RRC message or the HandoverPreparationInfo IE.

[0114] Upon identifying the C-SN configuration indicated in the handover request message, T-MN 104B determines 620A to release the C-SN configuration stored at UE 102. In response to this determination, T-MN 104B generates a handover command message including the C-SN configuration field / IE to be released. The handover command message also includes one or more random access configurations required for UE 102 to be handed over to T-MN 104B. In some implementations, the handover command message may have additional fields, such as mobility fields (e.g., the mobilityControlInfo field or the reconfigurationWithSync field). T-MN 104B then sends a 622A handover request response message including the handover command message to S-MN 104A in response to receiving the 618A handover request message. In some implementations, T-MN 104B may include a configuration ID associated with the C-SN configuration in the C-SN configuration field / IE to be released.

[0115] In implementations where S-MN 104A does not have a direct interface with T-MN 104B, S-MN 104A, CN 110, and T-MN 104B can jointly execute a CN program similar to that described above for scenario 300A.

[0116] Next, upon receiving a handover command message (i.e., from CN 110 or T-MN 104B), S-MN 104A sends a 624A handover command message to UE 102, causing UE 102 to release the C-SN configuration stored in 626A. In one embodiment, UE 102 can identify the configuration ID included in the C-SN configuration field / IE to be released, and release the C-SN configuration associated with that configuration ID. In some embodiments, if UE 102 can identify the configuration ID included in the C-SN configuration field / IE to be released, UE 102 can also release the conditions associated with the C-SN configuration. In other embodiments, if UE 102 can identify the configuration ID included in the C-SN configuration field / IE to be released, UE 102 releases the condition configuration field / IE that includes the C-SN configuration and the conditions. In some implementations, this condition may be associated with at least one measurement configuration (e.g., MeasConfig IE) configured by S-MN 104A to UE 102 before sending a handover command message to UE 102. At least one measurement configuration is associated with a measurement identifier (e.g., MeasId IE). In some implementations, UE 102 may release at least one measurement configuration if it can identify the configuration ID included in the C-SN configuration field / IE to be released. In other implementations, UE 102 does not release at least one measurement configuration if it identifies the configuration ID included in the C-SN configuration field / IE to be released. Instead, UE 102 releases the measurement configuration if it identifies a measurement identifier (associated with a measurement configuration in at least one measurement configuration) in the list of measurement identifiers to be removed field / IE (e.g., measIdToRemoveList) in the handover command message. T-MN 104B can determine the release measurement configuration in response to determining the 620A release C-SN configuration, and as a result, include the list field / IE of measurement identifiers to be removed in the handover command message. In some scenarios, if UE 102 initiates a random access procedure when it detects that the conditions are met according to the C-SN configuration and receives the 624A handover command, the UE can abort the random access procedure in response to the handover command.

[0117] UE 102 also performs an immediate handover with T-MN 104B in response to a handover command message. During the handover, UE 102 performs a random access procedure (628A) with T-MN 104B via T-PCell 124B, for example, using one or more random access configurations in the handover command message. During or after the random access procedure, UE 102 sends a handover completion message (630A). If UE 102 successfully completes the random access procedure, UE 102 transmits control signals and data (632A) via PCell 124B and MN 104B.

[0118] In some scenarios, in response to S-MN 104A determining that 616A is performing immediate handover or receiving a 622 handover request response message, S-MN 104A can send a 634A SN release request message to C-SN 106B, causing C-SN 106B to release its C-SN configuration. Therefore, C-SN 106B does not need to waste its resources maintaining the C-SN configuration, because UE 102 is no longer configured to use the C-SN configuration to communicate with C-SN 106B. C-SN 106B can then send a 636A SN release request response message to S-MN 104A. Events 634A and 636A occur in... Figure 6A They are collectively referred to as the Conditional SN Release Procedure 680A.

[0119] In some implementations, if S-MN 104A is an eNB or a next-generation eNB (ng-eNB), the RRC reconfiguration message and the RRC reconfiguration complete message can be respectively an RRCConnectionReconfiguration message and an RRCConnectionReconfigurationComplete message. If S-MN 104A is a gNB, the RRC reconfiguration message and the RRC reconfiguration complete message can be respectively an RRCReconfiguration message and an RRCReconfigurationComplete message.

[0120] In some implementations, if S-MN 104A is an eNB or ng-eNB, the handover command message and the handover completion message can be RRCConnectionReconfiguration and RRCConnectionReconfigurationComplete messages, respectively. If S-MN 104A is a gNB, the handover command message and the handover completion message can be RRCReconfiguration and RRCReconfigurationComplete messages, respectively.

[0121] In some implementations, the C-SN configuration may be a complete and self-contained configuration (i.e., a full configuration). The C-SN configuration may include a full configuration indication (IE or field) indicating that the C-SN configuration is a full configuration. If UE 102 is connected to C-SN 106B, UE 102 may use the C-SN configuration (i.e., the full configuration) to communicate with C-SN 106B without referencing the SN configuration. In other implementations, the C-SN configuration is an incremental configuration because the C-SN configuration may include one or more configurations "above" the SN configuration (i.e., one or more configurations not included in the SN configuration). If UE 102 is connected to C-SN 106B, UE 102 may use the C-SN configuration (i.e., the incremental configuration) along with the SN configuration to communicate with C-SN 106B.

[0122] In some implementations, the C-SN configuration may include multiple configuration parameters for UE 102 to communicate with C-SN 106B via C-PSCell 126B. These multiple configuration parameters may configure radio resources for UE 102 to communicate with C-SN 106B via C-PSCell 126B and zero or more candidate secondary cells (C-SCells) of C-SN 106B. These multiple configuration parameters may configure zero or more radio bearers. The one or more radio bearers may include SRBs and / or / multiple DRBs. Similarly, the SN configuration may include multiple configuration parameters for UE 102 to communicate with SN 106A via PSCell 126A and zero or more secondary cells (SCells) of SN 106A. These multiple configuration parameters may configure radio resources for UE 102 to communicate with SN 106A via PSCell 126A and zero or more SCells of SN 106A. These multiple configuration parameters may configure zero or more radio bearers. One or more radio bearers may include SRBs and / or (multiple) DRBs.

[0123] In some implementations, C-SN configuration may include configuring a group configuration (CellGroupConfig) IE for C-PSCell 126B, and may configure zero or one or more C-SCells of C-SN 106B. In one implementation, C-SN configuration may be an RRCReconfiguration message, RRCReconfiguration-IE, or CellGroupConfig IE conforming to 3GPP TS 38.331. A complete configuration indication may be a field or IE conforming to 3GPP TS 38.331. In other implementations, C-SN configuration may include configuring an SCG-ConfigPartSCG-r12 IE for C-PSCell 126B, and may configure zero or one or more C-SCells of C-SN 106B. In one implementation, C-SN configuration may be an RRCConnectionReconfiguration message, RRCConnectionReconfiguration-IE, or ConfigPartSCG-r12 IE conforming to 3GPP TS 36.331. The full configuration instruction can be a field or IE conforming to 3GPP TS 36.331. In another implementation, the C-MN configuration can be included in a conditional configuration field or IE, and the conditional configuration field / IE can also be included in an RRCReconfiguration message, RRCReconfiguration-IE, or CellGroupConfig IE conforming to 3GPP TS 38.331. In other implementations, the C-MN configuration can be an RRCConnectionReconfiguration message, RRCConnectionReconfiguration-IE, or ConfigPartSCG-r12IE conforming to 3GPP TS 36.331.

[0124] In some implementations, the SN configuration may include configuring the CellGroupConfig IE for PSCell 126A, and may configure zero or one or more SCells for SN 106A. In one implementation, the SN configuration may be an RRCReconfiguration message, RRCReconfiguration-IE, or CellGroupConfig IE conforming to 3GPPTS 38.331. In other implementations, the SN configuration may include configuring the SCG-ConfigPartSCG-r12IE for PSCell 126A, and may configure zero or one or more SCells for SN 106A. In one implementation, the SN configuration may be an RRCConnectionReconfiguration message, RRCConnectionReconfiguration-IE, or ConfigPartSCG-r12IE conforming to 3GPPTS 36.331.

[0125] exist Figure 6B In scenario 600B, similar to event 670A, UE 102, S-MN 104A, C-SN 106B and SN106A jointly execute the 670B CSAC configuration procedure.

[0126] Later, and before UE 102 determines that the conditions for condition SN change are met, similar to events 616A and 618A respectively, S-MN 104A determines that 616B performs an immediate handover procedure with T-MN 104B, and subsequently sends a 618B handover request message to T-MN 104B via an interface (e.g., the X2 / Xn interface) to request immediate handover of UE 102.

[0127] exist Figure 6A In the process, T-MN 104B identifies the C-SN configuration indicated in the handover request message to determine whether 620A releases the C-SN configuration stored at UE 102, while Figure 6B In this context, the T-MN 104B ignores (or discards) the C-SN configuration indicated in the 620B handover request message. Therefore, in... Figure 6A In the process, T-MN 104B generates a handover command message that includes the C-SN configuration field / IE to be released, while... Figure 6B In this process, T-MN 104B generates a handover command message that does not include the C-SN configuration field / IE to be released. T-MN 104B then responds to receiving the 618B handover request message by sending a 622B handover request response message to S-MN 104A, which includes the handover command message.

[0128] In implementations where S-MN 104A does not have a direct interface with T-MN 104B, S-MN 104A, CN 110, and T-MN 104B can jointly execute a CN program similar to that described above for scenario 300A.

[0129] Next, upon receiving a handover command message (i.e., from CN 110 or T-MN 104B), S-MN 104A sends a 624B handover command message to UE 102, causing UE 102 to release the C-SN configuration stored in 626B. In one embodiment, UE 102 is configured to release the stored C-SN configuration when it is recognized that the handover command message does not include the C-SN configuration field / IE to be released. In some embodiments, UE 102 may also be configured to release the conditions associated with the stored C-SN configuration when it is recognized that the handover command message does not include the C-SN configuration field / IE to be released. In other embodiments, UE 102 releases a condition configuration field / IE that includes the C-SN configuration and the conditions when it is recognized that the handover command message does not include the C-SN configuration field / IE to be released. In some implementations, this condition may be associated with at least one measurement configuration (e.g., MeasConfig IE) configured by S-MN 104A to UE 102 before sending a handover command message to UE 102. At least one measurement configuration is associated with a measurement identifier (e.g., MeasId IE). In some implementations, UE 102 may release at least one measurement configuration if it recognizes that the handover command message does not include the C-SN configuration field / IE to be released. In other implementations, UE 102 does not release at least one measurement configuration if it recognizes that the handover command message does not include the C-SN configuration field / IE to be released. Instead, if UE 102 recognizes a measurement identifier (associated with a measurement configuration in at least one measurement configuration) in the list of measurement identifiers to be removed field / IE (e.g., measIdToRemoveList) in the handover command message, UE 102 releases the measurement configuration. T-MN 104B may determine to release a measurement configuration in response to ignoring the 620B C-SN configuration, and as a result, include the list of measurement identifiers to be removed field / IE in the handover command message.

[0130] UE 102 then performs immediate handover with T-MN 104B by executing the 628B random access procedure with T-MN 104B via T-PCell 124B, sending a 630B handover completion message during or after the random access procedure, and transmitting 632B control signals and data via PCell 124B and MN 104B (similar to events 628A, 630A, and 632A, respectively) if UE 102 successfully completes the random access procedure. In some scenarios, similar to event 680A, S-MN 104A and C-SN 106B jointly execute the 680B conditional SN release procedure, causing C-SN 106B to release the C-SN configuration.

[0131] exist Figure 7 In scenario 700, similar to event 670A, UE 102, S-MN 104A, C-SN 106B and SN106A jointly execute the 760CSAC configuration procedure.

[0132] Later, and before UE 102 determines that the conditions for condition SN change are met, similar to event 616A, S-MN104A determines 716 to execute the immediate handover procedure with T-MN 104B. Figure 6A In the process, S-MN 104A sends a 618A handover request message, including S-MN configuration and C-SN configuration, to T-MN 104B, while... Figure 7 In this process, S-MN 104A generates an RRC message (e.g., an RRC reconfiguration message) that includes S-MN configuration but not C-SN configuration (717), and then sends a handover request message (718) including the RRC message to T-MN 104B. In some implementations, S-MN 104A may include the RRC message in the HandoverPreparationInfoIE and include the HandoverPreparationInfoIE in the handover request message.

[0133] Therefore, in Figure 6A In the process, T-MN 104B generates a handover command message including the C-SN configuration field / IE to be released, and in response to receiving the 618 handover request message, sends a 622A handover request response message including the handover command message to S-MN 104A. Figure 7 In this process, T-MN 104B generates a handover command message that does not include the C-SN configuration field / IE to be released, and in response to receiving the 718 handover request message, sends a 722 handover request response message including the handover command message to S-MN 104A.

[0134] In implementations where S-MN 104A does not have a direct interface with T-MN 104B, S-MN 104A, CN 110, and T-MN 104B can jointly execute a CN program similar to that described above for scenario 300A.

[0135] Then, upon receiving a handover command message (i.e., from CN 110 or T-MN 104B), similar to event 626B, S-MN 104A sends a handover command message 724 to UE 102, causing UE 102 to release the C-SN configuration stored in 726.

[0136] UE 102 then performs immediate handover with T-MN 104B by executing the random access procedure 728 with T-MN 104B via T-PCell 124B, sending a 730 handover completion message during or after the random access procedure, and transmitting 732 control signals and data via PCell 124B and MN 104B (similar to events 628B, 630B, and 632B, respectively) if UE 102 successfully completes the random access procedure. In some scenarios, similar to event 680B, S-MN 104A and C-SN 106B jointly execute the 780 conditional SN release procedure, causing C-SN 106B to release the C-SN configuration.

[0137] exist Figure 8 In scenario 800, similar to event 670A, UE 102, S-MN 104A, C-SN 106B and SN106A jointly execute the 860CSAC configuration procedure.

[0138] Later, and before UE 102 determines that the conditions for condition SN change are met, similar to event 716, S-MN104A determines 816 to perform the immediate handover procedure with T-MN 104B. Figure 7 In the process, S-MN 104A and T-MN 104B jointly execute immediate handover events 717, 718, 722, and 724 to cause UE 102 to release the C-SN configuration stored in 726, while Figure 8In the process, before initiating an immediate handover procedure, S-MN 104A sends an RRC reconfiguration message (817) to UE 102, including the C-SN configuration field / IE to be released, causing UE 102 to release the C-SN configuration stored (826). In response to receiving the RRC reconfiguration message, UE 102 releases the C-SN configuration (826) and sends an RRC reconfiguration complete message (819) back to S-MN 104A. In one implementation, UE 102 can identify the configuration ID included in the C-SN configuration field / IE to be released, and release the C-SN configuration associated with that configuration ID. In some implementations, if UE 102 identifies the configuration ID included in the C-SN configuration field / IE to be released, UE 102 can also release the conditions associated with the C-SN configuration. In other implementations, if UE 102 identifies the configuration ID included in the C-SN configuration field / IE to be released, UE 102 releases the condition configuration field / IE that includes the C-SN configuration and the conditions. In some implementations, this condition may be associated with at least one measurement configuration (e.g., MeasConfig IE) configured by S-MN 104A to UE 102 before sending an RRC reconfiguration message to UE 102. At least one measurement configuration is associated with a measurement identifier (e.g., MeasId IE). In some implementations, UE 102 may release at least one measurement configuration if it identifies a configuration ID included in the C-SN configuration field / IE to be released. In other implementations, UE 102 does not release at least one measurement configuration if it identifies a configuration ID included in the C-SN configuration field / IE to be released. Instead, UE 102 releases the measurement configuration if it identifies a measurement identifier (associated with a measurement configuration in at least one measurement configuration) in the list of measurement identifiers to be removed field / IE (e.g., measIdToRemoveList) in the RRC reconfiguration message. The S-MN 104A can determine the release of measurement configurations in response to the determination 816 performing an immediate handover, and as a result, include the list field of measurement identifiers to be removed / IE in the RRC reconfiguration message.

[0139] Next, similar to event 718, S-MN 104A initiates an immediate handover procedure by sending a handover request message (818) including the S-MN configuration to T-MN 104B to request immediate handover of UE 102. In some implementations, S-MN 104A may include the S-MN configuration in the HandoverPreparationInfo IE and also include the HandoverPreparationInfo IE in the handover request message. In some implementations, S-MN 104A may include the S-MN configuration in an RRC message (e.g., an RRC reconfiguration message) within the HandoverPreparationInfo IE and also include the HandoverPreparationInfo IE in the handover request message.

[0140] Similar to event 722, in response to receiving the handover request message, T-MN 104B generates a handover command message that does not include the C-SN configuration field / IE to be released, and sends a handover request response message 822, including the handover command message, to S-MN 104A. In other embodiments, event 818 may occur before event 819 or 817, such that event 818 may not respond to event 819.

[0141] In implementations where S-MN 104A does not have a direct interface with T-MN 104B, S-MN 104A, CN 110, and T-MN 104B can jointly execute a CN program similar to that described above for scenario 300A.

[0142] Next, upon receiving a handover command message (i.e., from CN 110 or T-MN 104B), S-MN 104A sends a handover command message 824 to UE 102. UE 102 then performs immediate handover with T-MN 104B by executing a random access procedure with T-MN 104B via T-PCell 124B (step 828), sending a handover completion message during or after the random access procedure, and transmitting control signals and data with MN 104B via PCell 124B (similar to events 728, 730, and 732, respectively) if UE 102 successfully completes the random access procedure. In some scenarios, similar to event 780, S-MN 104A and C-SN 106B jointly execute a conditional SN release procedure (step 880), causing C-SN 106B to release the C-SN configuration.

[0143] refer to Figure 9A and Figure 9BThe diagram illustrates a scenario in which the RAN initially provides the UE 102 with the conditional configurations for CHO and CSAC and later determines to release the two conditional configurations stored at the UE 102 during the immediate handover procedure.

[0144] exist Figure 9A In scenario 900A, similar to event 360A, UE 102, S-MN 104A, and C-MN 108 jointly execute the 960A conditional handover configuration procedure. Similar to event 670A, UE 102, S-MN 104A, C-SN 106B, and SN 106A jointly execute the 970A CSAC configuration procedure.

[0145] Later, and before UE 102 determines that the conditions for handover to C-MN 108 and / or the conditions for condition SN change are met, similar to events 316A, 616A and 318A, 618A respectively, S-MN 104A determines that 916A performs an immediate handover procedure with T-MN 104B, and subsequently sends a 918A handover request message to T-MN 104B via an interface (e.g., the X2 / Xn interface) to request immediate handover of UE 102. The handover request message includes S-MN configurations that make T-MN 104B aware of any pre-existing configurations known to UE 102 (e.g., S-MN configurations) to determine the additional configurations(s) still required by UE 102 when performing the immediate handover procedure from S-MN 104A to T-MN 104B. Furthermore, because T-MN 104B is unaware of the C-MN and C-SN configurations stored at UE 102, S-MN 104A also includes the C-MN and C-SN configurations in the handover request message, so that T-MN 104B is aware of the C-MN and C-SN configurations stored at UE 102 when the handover request message is received.

[0146] Upon identifying the C-MN and C-SN configurations indicated in the handover request message, similar to events 320A and 620A, T-MN 104B determines that 920A releases the C-MN and C-SN configurations stored at UE 102.

[0147] In response to this determination, T-MN 104B generates a handover command message, which includes the C-MN configuration field / IE to be released, the C-SN configuration field / IE to be released, and one or more random access configurations required for UE 102 to be handed over to T-MN 104B. Similar to events 322A and 622A, T-MN 104B then sends a 922A handover request response message, including the handover command message, to S-MN 104A in response to receiving a 918A handover request message. In implementations where S-MN 104A does not have a direct interface with T-MN 104B, S-MN 104A, CN 110, and T-MN 104B can jointly execute a CN procedure similar to that described above for scenario 300A.

[0148] Next, upon receiving a handover command message (i.e., from CN 110 or T-MN 104B), similar to events 324A and 624A, S-MN 104A sends a 924A handover command message to UE 102, causing UE 102 to release the C-MN configuration and C-SN configuration stored in 926A, similar to events 326A and 626A.

[0149] UE 102 then performs immediate handover with T-MN 104B by executing a 928A random access procedure with T-MN 104B via T-PCell 124B, sending a 930A handover completion message during or after the random access procedure, and transmitting 932A control signals and data via PCell 124B and MN 104B (similar to events 328A, 330A, and 332A, respectively) if UE 102 successfully completes the random access procedure. In some scenarios, similar to event 334A, S-MN 104A can send a 934A handover cancellation message to C-MN 108, causing C-MN 108 to release the C-MN configuration. In some scenarios, similar to event 680A, S-MN 104A and C-SN 106B jointly execute a 980A conditional SN release procedure, causing C-SN 106B to release the C-SN configuration.

[0150] exist Figure 9B In scenario 900B, similar to event 960A, UE 102, S-MN 104A, and C-MN 108 jointly execute the 960B conditional handover configuration procedure. Similar to event 970A, UE 102, S-MN 104A, C-SN 106B, and SN 106A jointly execute the 970B CSAC configuration procedure.

[0151] Later, and before UE 102 determines that the conditions for handover to C-MN 108 and / or the conditions for condition SN change are met, similar to events 916A and 918A respectively, S-MN 104A determines that 916B performs an immediate handover procedure with T-MN 104B, and subsequently sends a 918B handover request message to T-MN 104B via an interface (e.g., the X2 / Xn interface) to request immediate handover of UE 102. Figure 9A In the process, T-MN 104B identifies the C-MN configuration and C-SN configuration indicated in the handover request message to determine whether 920A releases the C-MN configuration and C-SN configuration stored at UE 102, while Figure 9B In this context, the T-MN 104B ignores (or discards) the C-MN and C-SN configurations indicated in the 920B handover request message. Therefore, in... Figure 9A In the process, T-MN 104B generates a handover command message that includes the C-MN configuration field / IE to be released and the C-SN configuration field / IE to be released, while... Figure 9B In this process, T-MN 104B generates a handover command message that does not include the C-MN configuration field / IE to be released and the C-SN configuration field / IE to be released. Similar to events 322B and 622B, T-MN 104B then responds to receiving the 918B handover request message by sending a 922B handover request response message to S-MN 104A, which includes the handover command message.

[0152] In implementations where S-MN 104A does not have a direct interface with T-MN 104B, S-MN 104A, CN 110, and T-MN 104B can jointly execute a CN program similar to that described above for scenario 300A.

[0153] Next, upon receiving a handover command message (i.e., from CN 110 or T-MN 104B), similar to events 324B and 624B, S-MN 104A sends a handover command message 924B to UE 102, causing UE 102 to release the C-MN configuration and C-SN configuration stored in 926B, similar to events 326B and 626B.

[0154] UE 102 then performs immediate handover with T-MN 104B by executing a 928B random access procedure with T-MN 104B via T-PCell 124B, sending a 930B handover completion message during or after the random access procedure, and transmitting 932B control signals and data via PCell 124B and MN 104B if UE 102 successfully completes the random access procedure (similar to events 928A, 930A, and 932A, respectively). In some scenarios, similar to event 934A, S-MN 104A can send a 934B handover cancellation message to C-MN 108, causing C-MN 108 to release the C-MN configuration. In some scenarios, similar to event 980A, S-MN 104A and C-SN 106B jointly execute a 980B conditional SN release procedure, causing C-SN 106B to release the C-SN configuration.

[0155] In some alternative implementations of events 918A, 918B, 920A, 920B, 922A, 922B, 924A, and 924B, similar to events 417, 418, 717, and 718, S-MN 104A may generate an RRC message (e.g., an RRC reconfiguration message) that includes the S-MN configuration but excludes the C-MN and C-SN configurations, and then send a handover request message including the RRC message to T-MN 104B. Therefore, similar to events 422, 424, 722, and 724, T-MN 104B generates a handover command message that excludes the C-MN configuration field / IE to be released and the C-SN configuration field / IE to be released, and in response to receiving the handover request message, sends a handover request response message including the handover command message to S-MN 104A.

[0156] refer to Figure 10 and Figure 11 The diagram illustrates a scenario where the RAN initially provides the CPAC conditional configuration to the UE 102 and later determines to release the conditional configuration stored at the UE 102 during an instant SN add / change procedure.

[0157] exist Figure 10 In scenario 1000, base station 104A operates as the MN of UE 102, base station 106A operates as the S-SN of UE 102, and base station 104B operates as the T-SN of UE 102.

[0158] Initially, UE 102 in DC transmits 1002 data via PCell 124A and MN 104A using MN configuration, and transmits 1002 data via PSCell (e.g., different from PSCell 126A) and S-SN 106A using SN configuration.

[0159] Later, when determining that 1004 is configuring the C-SN configuration for CPAC procedures for UE 102, S-SN 106A provides the C-SN configuration to UE 102. The C-SN configuration includes information that will enable UE 102 to communicate with S-SN 106A via C-PSCell (e.g., C-PSCell 126A). S-SN 106A includes the C-SN configuration in an RRC reconfiguration message for UE 102 and subsequently sends the RRC reconfiguration message to UE 102. In some implementations, S-SN 106A may include the RRC reconfiguration message in an SN add request response message, SN modify request response message, SN modify request message, or SN change request message. The SN add request response message, SN modify request response message, SN modify request message, or SN change request message may conform to 3GPP TS 36.423 or TS 38.423.

[0160] To provide C-SN configuration to UE 102, in some implementations, S-SN 106A sends an RRC reconfiguration message 1012A, including the C-SN configuration, to MN 104A, which in turn sends an RRC reconfiguration message 1013A to UE 102. MN 104A may send the 1013RRC reconfiguration message in a first RRC container message and send a first RRC container message to UE 102. In response to receiving the RRC reconfiguration message, UE 102 may optionally send an RRC reconfiguration completion message 1014A to MN 104A. UE 102 may include the RRC reconfiguration completion message in a first RRC container response message and send a first RRC container response message to MN 104A. Upon receiving the 1014A RRC reconfiguration completion message, MN 104A may optionally send an SN reconfiguration completion message 1015A to S-SN 106A. Events 1012A, 1013A, 1014A, and 1015A are in Figure 10 They are collectively referred to as CPAC program 1060A.

[0161] As an alternative to executing CPAC procedure 1060A, in other implementations, S-SN 106A uses SRB3 to directly send an RRC reconfiguration message including C-SN configuration to UE 102 via SRB3. UE 102 then optionally responds by sending an RRC reconfiguration complete message via S-SN 1014B to S-SN 106A upon receiving the RRC reconfiguration message. Events 1012B and 1014B occur in... Figure 10 In this context, it is collectively referred to as CPAC program 1060B.

[0162] In some implementations, S-SN 106A includes conditions (or conditions) for UE 102 to detect in the C-SN configuration or RRC reconfiguration message, such that if the conditions are met, UE 102 can communicate with S-SN 106A via C-PSCell 126A. S-SN 106A may include the C-SN configuration in the condition configuration field or IE of the RRC reconfiguration message. S-SN 106A may also include a configuration ID associated with the C-SN configuration in the condition configuration field / IE, enabling UE 102 to recognize and store the C-SN configuration. S-SN 104A may assign a configuration ID.

[0163] Later, and before UE 102 determines that the CPAC conditions are met, S-SN 106A or MN 104A initiates an immediate SN addition or modification procedure with T-SN 104B, either blindly or in response to detecting a suitable event, to enable communication between T-SN 104B and UE 102. For example, S-SN 106A may determine to perform the immediate SN addition or modification procedure in response to one or more measurement results received from UE 102 or obtained by S-SN 106A from measurements of signals received from UE 102. As another example, MN 104A may determine to perform the immediate SN addition or modification procedure in response to one or more measurement results received from UE 102 or obtained by MN 104A from measurements of signals received from UE 102.

[0164] If S-SN 106A initiates an immediate SN add or change procedure (i.e., an SN-initiated SN add or change procedure), S-SN 106A can send a Request SN Change message (1015) including the C-SN configuration to MN 104A, and MN 104A then determines to execute the immediate SN add or change procedure (1016). In some implementations, S-SN 106A can include the C-SN configuration in a CG-Config IE (or an RRC inter-node message) and include the CG-Config IE in the Request SN Change message. If the configuration ID associated with the C-SN configuration is assigned by S-SN 106A, the Request SN Change message can also include that configuration ID. In some implementations, the configuration ID can be included in the CG-Config IE. In one implementation, S-SN 106A can generate an RRC message (e.g., an RRC reconfiguration message) including the C-SN configuration and include the RRC message in the CG-Config IE. The CG-Config IE can conform to 3GPP TS 38.331.

[0165] As an alternative to an SN-initiated SN addition or modification procedure, for example, in response to one or more measurement results received from UE 102; or in response to receiving a CG-Config IE in an SN message (e.g., a request for SN modification message or an SN modification request response message) from S-SN 106A, MN 104A may determine that 1016 performs an immediate SN addition or modification procedure (i.e., an MN-initiated SN addition or modification procedure).

[0166] In response to receiving a 1015 request for SN change message or determining 1016 to perform an immediate SN add or change procedure, MN104A sends a 1018 SN add request message to T-SN 104B via an interface (e.g., the X2 / Xn interface). The SN add request message includes the SN configuration, making T-MN 104B aware of any pre-existing configurations (e.g., SN configurations) known to UE 102, to determine the additional configuration(s) that UE 102 still needs when performing an immediate SN add or change. Furthermore, because T-SN 104B is not aware of the C-SN configuration stored at UE 102, S-MN 104A includes the C-SN configuration in the SN add request message, so that T-SN 104B is aware of the C-SN configuration stored at UE 102 upon receiving the SN add request message. In some implementations, MN 104A may include a configuration ID associated with the C-SN configuration in the SN add request message. In some implementations, the MN 104A may include the C-SN configuration in the CG-ConfigInfo IE (or RRC inter-node message) and also in the SN add request message. In other implementations, the configuration ID may be included in the CG-ConfigInfo IE. In some implementations, the MN 104A may include the RRC message received in the CG-Config IE in the request SN change message or the SN message. That is, the MN 104A receives the SN message before sending the SN add request message 1018. The CG-ConfigInfo IE may conform to 3GPP TS 38.331.

[0167] Upon identifying the C-SN configuration indicated in the SN Add Request message, T-SN 104B determines 1020 to release the C-SN configuration stored at UE 102. In response to this determination, T-SN 104B generates an RRC reconfiguration message including the C-SN configuration field / IE to be released. The RRC reconfiguration message also includes one or more random access configurations required by UE 102 to perform an on-the-spot SN add or change procedure with T-SN 104B. T-SN 104B then sends an SN Add Request Response message 1022, including the RRC reconfiguration message, to MN 104A in response to receiving the SN Add Request message 1018. In some implementations, T-SN 104B may include the RRC reconfiguration message in the CG-Config IE and the CG-Config IE in the SN Add Request Response message. T-SN 104B may include the configuration ID associated with the C-SN configuration in the C-SN configuration field / IE to be released.

[0168] Next, MN 104A sends a 1024RRC reconfiguration message to UE 102, causing UE 102 to release the C-SN configuration stored in 1026. MN 104A may send the 1024RRC reconfiguration message in a second RRC container message and also send a second RRC container message to UE 102. In one implementation, UE 102 may identify the configuration ID included in the C-SN configuration field / IE to be released, and release the C-SN configuration associated with that configuration ID. Before or after sending the 1024RRC reconfiguration message to UE 102, MN 104 may optionally send a 1023SN change confirmation message to S-SN 106A in response to receiving a 1015 request SN change message. In some implementations, if UE 102 identifies the configuration ID included in the C-SN configuration field / IE to be released, UE 102 may also release the conditions associated with the C-SN configuration. In other implementations, if UE 102 identifies a configuration ID included in the C-SN configuration field / IE to be released, then UE 102 releases the condition configuration field / IE that includes the C-SN configuration and a condition. In some implementations, this condition may be associated with at least one measurement configuration (e.g., MeasConfig IE) configured to UE 102 by S-SN 106A before sending an RRC reconfiguration message to UE 102. At least one measurement configuration is associated with a measurement identifier (e.g., MeasId IE). In some implementations, if UE 102 identifies a configuration ID included in the C-SN configuration field / IE to be released, then UE 102 may release at least one measurement configuration. In other implementations, if UE 102 identifies a configuration ID included in the C-SN configuration field / IE to be released, then UE 102 does not release at least one measurement configuration. Conversely, if UE 102 identifies a measurement identifier (associated with a measurement configuration in at least one measurement configuration) in the To-Remove Measurement Identifier List field / IE (e.g., measIdToRemoveList) in the RRC reconfiguration message, then UE 102 releases the measurement configuration. T-SN 104B may determine to release the measurement configuration in response to determining 1020 to release the C-SN configuration, such that T-SN 104B includes the To-Remove Measurement Identifier List field / IE in the RRC reconfiguration message.

[0169] In response to releasing the 1026C-SN configuration, UE 102 can send a 1027RRC reconfiguration complete message to MN 104A. UE 102 can include the RRC reconfiguration complete message in a second RRC container response message and send a second RRC container response message to MN 104A. Upon receiving the 1027RRC reconfiguration complete message, MN 104A sends a 1029SN reconfiguration complete message to T-SN 104B.

[0170] UE 102 also responds to a handover command message to perform an immediate SN addition or change procedure with T-MN 104B. During the SN addition or change procedure, UE 102 (e.g., by using one or more random access configurations in an RRC reconfiguration message) performs a random access procedure with T-SN 104B via T-PSCell 124B 1028. If UE 102 successfully completes the random access procedure, UE 102 communicates with MN 104A and SN 104B in the DC via PSCell 126A 1032. To perform the random access procedure, UE 102 can disconnect from either PSCell (e.g., different from PSCell 126A) or S-SN 106A.

[0171] In some implementations, the RRC reconfiguration message may include an RRCReconfiguration-IE or CellGroupConfig IE configuring PSCell 124B, and may configure zero or one or more SCells of T-SN 104B. The RRC reconfiguration message may include a RadioBearerConfig IE. In other implementations, the RRC reconfiguration message 1024 may include an SCG-ConfigPartSCG-r12IE configuring PSCell 124B, and may configure zero or one or more SCells of T-SN 104B.

[0172] In some implementations, if MN 104A is an eNB or a next-generation eNB (ng-eNB), the RRC reconfiguration message, RRC reconfiguration complete message, RRC container messages (i.e., the first RRC container message and the second RRC container message), and RRC container response messages (i.e., the first RRC container response message and the second RRC container response message) can be respectively an RRCConnectionReconfiguration message, an RRCConnectionReconfigurationComplete message, an RRCConnectionReconfiguration message, and an RRCConnectionReconfigurationComplete message. If MN 104A is a gNB, the RRC reconfiguration message, RRC reconfiguration complete message, RRC container messages (i.e., the first RRC container message and the second RRC container message), and RRC container response messages (i.e., the first RRC container response message and the second RRC container response message) can be respectively an RRCReconfiguration message, an RRCReconfigurationComplete message, an RRCReconfiguration message, and an RRCReconfigurationComplete message.

[0173] In some implementations, such as Figure 1C As shown, T-SN 104B may include CU 172 and one or more DU 174s. DU 174 may include some configurations (e.g., one or more random access configurations, Physical Downlink Control Channel (PDCCH) configurations, Physical Uplink Control Channel (PUCCH) configurations, etc.) in the RRC reconfiguration message and send these configurations to CU 172. UE 102 can perform a random access procedure with DU 172 by using one or more random access configurations. CU 172 may include other configurations (e.g., SRB configuration, DRB configuration, security configuration, and / or measurement configuration) in the RRC reconfiguration message. In other embodiments, DU 174 may generate a CellGroupConfig IE in the RRC reconfiguration message, and CU 172 may generate a RadioBearerConfig IE.

[0174] exist Figure 11 In scenario 1100, similar to event 1012, UE 102 in DC transmits 1102 data via PCell 124A and MN 104A using MN configuration, and transmits 1102 data via PSCell (e.g., different from PSCell 126A) and S-SN 106A using SN configuration.

[0175] Later, when determining that 1104 is configuring the C-SN configuration for the CPAC procedure for UE 102, similar to event 1060A or alternatively similar to event 1060B, S-SN 106A provides the C-SN configuration to UE 102 by executing the 1160 CPAC procedure.

[0176] Later, and before UE 102 determines that the conditions for CPAC are met, in Figure 10 In response to receiving the CG-Config IE from the SN message from S-SN106A, MN 104A determines that 1016 will execute an immediate SN addition or change procedure (i.e., an SN addition or change procedure initiated by MN), while Figure 11 In the process, S-SN 106A determines that 1116 performs an instant SN addition or change procedure.

[0177] S-SN 106A then generates 1117, which includes the SN configuration but does not include the C-SN configuration (e.g., an RRC reconfiguration message), and then sends 1115, a request for SN change message including the RRC message, to MN 104A. In one implementation, the RRC message is included in the CG-Config IE, and the request for SN change message includes the CG-Config IE.

[0178] Similar to event 1018, in response to receiving the 1115 request SN change message, MN 104A sends the 1118 SN Add Request message, which includes an RRC message, to T-SN 104B via an interface (e.g., the X2 / Xn interface).

[0179] Upon receiving an SN Add Request message, in response to receiving SN Add Request message 1118 (similar to event 1022), T-SN 104B sends SN Add Request Response message 1122, which includes an RRC reconfiguration message, to MN 104A. Similar to event 1023, MN 104 may optionally send SN Change Confirmation message 1123 to S-SN 106A.

[0180] Next, similar to event 1024, MN 104A sends an RRC reconfiguration message 1124 to UE 102, causing UE 102 to release the C-SN configuration stored in 1126. In one implementation, UE 102 is configured to release the stored C-SN configuration when it is recognized that the RRC reconfiguration message does not include the C-SN configuration field / IE to be released. Before or after sending the RRC reconfiguration message 1124 to UE 102, in response to receiving a request for SN change message 1115, similar to event 1023, MN 104 may optionally send an SN change confirmation message 1123 to S-SN 106A. In some implementations, UE 102 may also release the conditions associated with the C-SN configuration when it is recognized that the RRC reconfiguration message does not include the C-SN configuration field / IE to be released. In other implementations, UE 102 releases the condition configuration field / IE that includes the C-SN configuration and the conditions when it is recognized that the RRC reconfiguration message does not include the C-SN configuration field / IE to be released. In some implementations, this condition may be associated with at least one measurement configuration (e.g., MeasConfig IE) configured by S-SN 106A to UE 102 before sending an RRC reconfiguration message to UE 102. At least one measurement configuration is associated with a measurement identifier (e.g., MeasId IE). In some implementations, UE 102 may release at least one measurement configuration if it recognizes that the RRC reconfiguration message does not include a C-SN configuration field / IE to be released. In other implementations, UE 102 does not release at least one measurement configuration if it recognizes that the RRC reconfiguration message does not include a C-SN configuration field / IE to be released. Instead, if UE 102 recognizes a measurement identifier (associated with a measurement configuration in at least one measurement configuration) in the list of measurement identifiers to be removed field / IE (e.g., measIdToRemoveList) in the RRC reconfiguration message, then UE 102 releases that measurement configuration. T-SN 104B can determine the change of 1116 from S-SN 106A to T-SN 106B in response to S-SN 106A, or in response to receiving an SN Add Request message, to determine the release of the measurement configuration, and as a result, include the list field of measurement identifiers to be removed / IE in the RRC reconfiguration message.

[0181] In response to the release of the 1126C-SN configuration, similar to event 1027, UE 102 can send a 1127RRC reconfiguration complete message to MN 104A, similar to event 1029, and MN 104A then sends a 1129SN reconfiguration complete message to T-SN 104B.

[0182] UE 102 also responds to the handover command message to perform an immediate SN addition or modification procedure with T-MN 104B. During the SN addition or modification procedure, similar to event 1028, UE 102 performs a random access procedure with T-SN 104B via T-PSCell 124B (1128). If UE 102 successfully completes the random access procedure, similar to event 1032, UE 102 communicates with the DCs of MN 104A and SN 104B (1132).

[0183] Figure 12 This is a flowchart depicting an example method 1200 implemented in a base station (e.g., MN 104A) for processing the release of conditional configuration stored at the user equipment (e.g., UE 102) when determining to configure a user equipment to connect to a target base station by including conditional configuration in an interface message.

[0184] In box 1201, the base station determines to configure the user equipment to connect to the target base station (e.g., in any of events 316A, 316B, 616A, 616B, 916A, 916B, 1016). This configuration may correspond to immediate procedures such as handover, SN addition or change, or PScell ​​addition or change.

[0185] In blocks 1202-1206, the base station generates an interface message and sends it to the target base station to request configuration from the user equipment (UE) to connect to the target base station (e.g., in any of events 318A, 318B, 618A, 618B, 918A, 918B, and 1018). The base station generates the interface message in block 1202 and includes the source base station configuration in the interface message. If the base station determines in block 1203 that the RAN previously provided conditional configuration to the UE, the process proceeds to block 1204, where the base station also includes the conditional configuration in the interface message. Otherwise, the process proceeds directly to block 1206, where the base station sends the interface message to the target base station. When the interface message includes the conditional configuration, the target base station becomes aware of the conditional configuration stored at the UE and can subsequently initiate the release of the conditional configuration at the UE.

[0186] In at least some cases, in box 1207, the base station receives an interface response message from the target base station. The interface response message may include an RRC message with an explicit or implicit release indicator for the conditional configuration, for connecting the UE to the target base station and releasing the conditional configuration at the UE (e.g., in any of events 322A, 322B, 622A, 622B, 922A, 922B, 1022).

[0187] In box 1208, the base station sends an interface response message to the UE with an explicit or implicit release indicator for the conditional configuration (e.g., in any of events 324A, 324B, 624A, 624B, 924A, 924B, 1024), causing the UE to release the conditional configuration.

[0188] Figure 13 This is a flowchart depicting an example method 1300 implemented in a base station (e.g., T-MN 104B, T-SN 104B) for processing the release of conditional configurations stored at a user equipment (e.g., UE 102) upon receiving a handover request message or an SN add request message.

[0189] In method 1300, at block 1302, the base station receives a first interface message from the source base station, the first interface message requesting radio resources for the user equipment and including conditional configuration for the user equipment (e.g., in any of events 318A, 618A, 918A, 1018).

[0190] In box 1304, the base station determines to generate an RRC message that includes a target base station configuration for the user equipment and a condition configuration field to be released for releasing the condition configuration at the user equipment (e.g., in any of events 320A, 620A, 920A, 1020).

[0191] In box 1306, the base station transmits a second interface message, including an RRC message, to the source base station (e.g., in any of events 322A, 622A, 922A, and 1022).

[0192] Figure 14 This is a flowchart depicting an example method 1400 implemented in a base station (e.g., T-MN 104B, T-SN 104B) for processing the release of conditional configurations stored at a user equipment (e.g., UE 102) upon receiving a handover request message or an SN add request message.

[0193] In method 1400, at block 1402, the base station receives a first interface message from the source base station, the first interface message requesting radio resources for the user equipment and including conditional configuration for the user equipment (e.g., in any of events 318B, 618B, and 918B).

[0194] In box 1404, the base station ignores conditional configurations (e.g., in any of events 320B, 620B, and 920B).

[0195] In box 1406, the base station determines to generate an RRC message that includes the target base station configuration for the user equipment (e.g., in any of events 320B, 620B, and 920B).

[0196] In box 1408, the base station sends a second interface message, including an RRC message, to the source base station (e.g., in any of events 322B, 622B, and 922B).

[0197] Figure 15 This is a flowchart depicting an example method 1500 implemented in a base station (e.g., MN 104A, SN 106A) for processing the release of conditional configuration stored at the user equipment (e.g., UE 102) when determining to configure a user equipment to connect to a target base station by not including conditional configuration in the interface message.

[0198] In method 1500, at block 1502, the base station determines to configure the user equipment to connect to the target base station (e.g., in any of events 416, 716, and 1116).

[0199] In box 1504, the base station generates a first RRC message that includes the source base station configuration but does not include the condition configuration (e.g., in any of events 417, 717, and 1117).

[0200] In box 1506, the base station transmits an interface message including a first RRC message to the target base station to request that the user equipment be configured to connect to the target base station (e.g., in any of events 418, 718, and 1118).

[0201] In block 1508, the base station receives an interface response message from the target base station, which includes a second RRC message for connecting the UE to the target base station and releasing the conditional configuration at the UE (e.g., in any of events 422, 722, and 1122).

[0202] In box 1510, the base station sends a second RRC message to the UE (e.g., in any of events 424, 724, and 1124) causing the UE to release the conditional configuration.

[0203] Figure 16 This is a flowchart depicting an example method 1600 implemented in a base station (e.g., MN 104A) for processing the release of conditional configuration stored at a user equipment (e.g., UE 102) when determining to configure a user equipment to connect to a target base station by including an identifier of the conditional configuration in an interface message.

[0204] In method 1600, at block 1602, the base station determines to configure the user equipment to connect to the target base station (e.g., in either event 516 or 816).

[0205] In box 1604, the base station generates a first RRC message including the condition configuration field to be released and sends it to the user equipment (e.g., in either event 517 or 817), causing the user equipment to release the condition configuration.

[0206] In box 1606, the base station sends a second RRC message to the user equipment to configure the user equipment to connect to the target base station (e.g., in either event 524 or 824).

[0207] Figure 17 This is a flowchart depicting an example method 1700 implemented in the RAN (e.g., base stations 104A and 104B) for processing the release of conditional configurations stored at a user equipment (e.g., UE 102).

[0208] In method 1700, at block 1702, the RAN sends to the user equipment (i) a conditional configuration related to the base station operating in the RAN and (ii) a condition to be satisfied by the UE before the conditional configuration is applied during the conditional procedure (e.g., in any one of events 360A, 360B, 460, 560, 670A, 670B, 760, 860, 960A, 960B, 970A, 970B, 1060A, 1060B, 1160).

[0209] In box 1704, the RAN then determines that the UE will execute an immediate procedure related to the RAN (e.g., in any of events 316A, 316B, 416, 516, 616A, 616B, 716, 816, 916A, 916B, 1016, 1116).

[0210] In box 1706, the RAN provides the user equipment with an indication of the UE release condition configuration (e.g., in any of events 324A, 324B, 424, 524, 624A, 624B, 724, 824, 924A, 924B, 1024, 1124).

[0211] Figure 18 This is a flowchart depicting an example method 1800 implemented in a user equipment (e.g., UE 102) for processing the release of conditional configurations stored at the user equipment.

[0212] In method 1800, at block 1802, the user equipment receives from the base station (i) a conditional configuration associated with the base station operating in the RAN and (ii) a condition to be satisfied by the UE before applying the conditional configuration during the conditional procedure (e.g., in any one of events 360A, 360B, 460, 560, 670A, 670B, 760, 860, 960A, 960B, 970A, 970B, 1013A, 1012B, 1160).

[0213] In box 1804, the user equipment receives from the base station an implicit or explicit indication of the UE release condition configuration (e.g., in any one of events 324A, 324B, 424, 517, 624A, 624B, 724, 817, 924A, 924B, 1024, 1124).

[0214] In box 1806, the user equipment responds to the indication to release the conditional configuration (e.g., in any of events 326A, 326B, 426, 526, 626A, 626B, 726, 826, 926A, 926B, 1026, 1126).

[0215] The following description can be applied to the description above.

[0216] A user equipment in which the technologies of this disclosure can be implemented (e.g., UE 102) can be any suitable device capable of wireless communication, such as a smartphone, tablet computer, laptop computer, mobile game console, point-of-sale (POS) terminal, health monitoring device, drone, camera, media streaming dongle or other personal media device, wearable device (such as a smartwatch), wireless hotspot, femtocell, or broadband router. Furthermore, in some cases, the user equipment can be embedded in an electronic system (such as a head unit of a vehicle or an advanced driver assistance system (ADAS)). Additionally, the user equipment can operate as an Internet of Things (IoT) device or a mobile internet device (MID). Depending on the type, the user equipment may include one or more general-purpose processors, computer-readable storage, a user interface, one or more network interfaces, one or more sensors, etc.

[0217] Some embodiments described in this disclosure include logic or multiple components or modules. A module can be a software module (e.g., code or machine-readable instructions stored on a non-transitory machine-readable medium) or a hardware module. A hardware module is a tangible unit capable of performing certain operations and can be configured or arranged in a particular manner. A hardware module may include dedicated circuitry or logic permanently configured (e.g., as a dedicated processor such as a field-programmable gate array (FPGA) or application-specific integrated circuit (ASIC)), digital signal processor (DSP), etc.) to perform certain operations. A hardware module may also include programmable logic or circuitry temporarily configured by software to perform certain operations (e.g., contained within a general-purpose processor or other programmable processor). The decision to implement a hardware module in dedicated and permanently configured circuitry or in temporarily configured (e.g., software-configured) circuitry may be driven by cost and time considerations.

[0218] When implemented in software, these technologies can be provided as part of an operating system, a library used by multiple applications, or a specific software application. The software can be executed by one or more general-purpose processors or one or more dedicated processors.

[0219] Aspect 1. A method for configuring a user equipment (UE) in a radio access network (RAN), the method comprising: sending (i) a conditional configuration associated with a base station operating in the RAN, and (ii) conditions to be satisfied by the UE before applying the conditional configuration during a conditional procedure, by processing hardware; determining, after sending, that the UE will execute an immediate procedure associated with the RAN; and providing the UE with an indication from the processing hardware to release the conditional configuration.

[0220] Aspect 2. The method according to aspect 1, wherein providing the indication includes sending a message to the UE including a release indicator instructing the UE to release the condition configuration.

[0221] Aspect 3. The method according to aspect 2, wherein sending the message includes: sending a handover command from a source base station that is different from the base station associated with the condition configuration.

[0222] Aspect 4. The method according to aspect 3, wherein determining that the UE will perform an immediate procedure related to the RAN includes determining at the source base station that the UE will perform an immediate procedure, the method further comprising: sending a handover request message including conditional configuration from the source base station to the target base station; and receiving at the source base station a handover request response message including a handover command from the target base station.

[0223] Aspect 5. The method according to aspect 3, comprising: receiving a handover request from a source base station at a target base station, the handover request including (i) conditional configuration and (ii) configuration associated with the source base station; determining at the target base station to discard the conditional configuration; generating a handover command including a release indicator at the target base station; and sending a handover request response message including the handover command from the target base station to the source base station.

[0224] Aspect 6, according to the method of aspect 2, wherein sending the message includes: sending a radio resource control (RRC) message from the RAN to the UE.

[0225] Aspect 7. The method according to aspect 6 further includes: sending a secondary node (SN) addition request including conditional configuration from a source base station to a target base station; and receiving a response message including a release indicator from the target base station at the source base station; wherein sending an RRC message is in response to receiving the response message.

[0226] Aspect 8. The method according to aspect 1, wherein providing the instruction includes: sending an instruction to the UE for initiating an immediate procedure, wherein the UE responds to the instruction to release the conditional configuration.

[0227] Aspect 9. The method according to aspect 8, wherein the instruction is one of: (i) a handover command or (ii) an RRC message including information related to a new SN or a new primary / secondary cell (PScell).

[0228] Aspect 10. The method according to aspect 1, wherein providing the indication includes providing the indication from the master node (MN); the method further includes: receiving conditional configuration from the MN at a target base station that is different from the base station associated with the conditional configuration; and sending a message from the target base station to the MN including a release indicator instructing the UE to release the conditional configuration.

[0229] Aspect 11. The method according to aspect 10, wherein generating the message includes generating a handover command.

[0230] Aspect 12. The method according to aspect 10, wherein generating the message includes generating an RRC reconfiguration message.

[0231] Aspect 13. The method according to aspect 1 further includes: sending an instruction from a base station that provides an indication to a base station associated with the conditional configuration for releasing the conditional configuration.

[0232] Aspect 14. The method according to any one of the preceding aspects, wherein: the base station associated with the condition configuration is a first base station; and the instantaneous procedure is associated with a second base station different from the first base station.

[0233] Aspect 15. The method according to any one of the preceding aspects, wherein the condition procedure is one of: (i) condition handover, (ii) condition SN change or addition, or (iii) condition PScell ​​change or addition.

[0234] Aspect 16. A RAN comprising processing hardware and configured to perform the method according to any one of the preceding aspects.

[0235] Aspect 17. A method for processing configuration in a user equipment (UE), the method comprising: receiving, by processing hardware, (i) a conditional configuration associated with a base station operating in the RAN and (ii) a condition to be satisfied by the UE before applying the conditional configuration during a conditional procedure; receiving, by processing hardware, an instruction from the RAN for the UE to release the conditional configuration after receiving the conditional configuration; and releasing the conditional configuration by processing hardware in response to the instruction.

[0236] Aspect 18. The method according to aspect 17, wherein receiving the indication includes receiving from the RAN a message including a release indicator indicating the UE release condition configuration.

[0237] Aspect 19. The method according to aspect 18, wherein receiving the message includes: receiving a handover command from a source base station that is different from the base station associated with the condition configuration.

[0238] Aspect 20. The method according to aspect 18, wherein receiving the message includes: receiving a Radio Resource Control (RRC) message from the RAN.

[0239] Aspect 21. The method according to aspect 17, wherein receiving the instruction includes: receiving from the RAN an instruction for initiating an immediate procedure.

[0240] Aspect 22. The method according to aspect 21, wherein the instruction is one of: (i) a handover command or (ii) an RRC message including information related to a new SN or a new primary / secondary cell (PScell).

[0241] Aspect 23. The method according to aspect 21, wherein the condition procedure is one of the following: (i) condition handover, (ii) condition SN change or addition, or (iii) condition PScell ​​change or addition.

[0242] Aspect 24. A UE, including processing hardware and configured to perform the method according to any one of aspects 17 to 23.

Claims

1. A method for configuring a user equipment (UE) performed in a radio access network (RAN), the method comprising: The source base station operating in the RAN sends (i) a conditional configuration related to a base station operating in the RAN that is different from the source base station and (ii) a condition to be satisfied by the UE before the conditional configuration is applied during a procedure in the conditional secondary node SN change or add procedure or the conditional primary and secondary cell PScell ​​change or add procedure. The source base station determines after the transmission that the UE will unconditionally execute the immediate procedures related to the RAN; as well as The source base station provides the UE with an indication that the UE will unconditionally execute the immediate procedure and release the conditional configuration.

2. The method according to claim 1, wherein, Providing the instruction includes sending a command to the UE to initiate the immediate procedure; and The instruction includes an implicit release indicator that instructs the UE to release the conditional configuration.

3. The method according to claim 2, wherein, Sending the instruction includes: sending a handover command from the source base station.

4. The method according to claim 3, further comprising: Send a handover request message, including the condition configuration, from the source base station to the target base station; as well as At the source base station, a handover request response message including the handover command is received from the target base station.

5. The method according to claim 2, wherein, Sending the instruction includes: sending a Radio Resource Control (RRC) message from the source base station to the UE, and the method further includes: Sending a secondary node SN addition request, including the condition configuration, from the source base station to the target base station; and At the source base station, a response message including the release indicator is received from the target base station; Sending an RRC message is in response to receiving the response message.

6. The method according to claim 1, wherein, Providing the instruction includes sending a message to the UE that includes an instruction for the UE to release the condition configuration display release indicator.

7. The method according to claim 1, wherein, Providing the instruction includes providing the instruction from the master node MN; the method further includes: Receive the condition configuration from the MN at a target base station that is different from the base station associated with the condition configuration; and A message is sent from the target base station to the MN, the message including a release indicator instructing the UE to release the condition configuration.

8. The method according to any one of the preceding claims, wherein: The base station associated with the aforementioned condition configuration is the first base station; and The instant procedure is associated with a second base station that is different from the first base station.

9. A radio access network (RAN) including processing hardware of a source base station and configured to perform the method according to any one of the preceding claims.

10. A method for processing configuration executed by a user equipment (UE), the method comprising: The UE receives (i) a conditional configuration associated with a base station operating in the radio access network (RAN) that is different from the source base station, and (ii) a condition to be satisfied before the UE applies the conditional configuration during a procedure in the conditional secondary node (SN) change or add procedure or the conditional primary / secondary cell (PScell) change or add procedure. Upon receiving the conditional configuration, the UE receives from the source base station an instruction that the UE will unconditionally execute an immediate procedure and release the conditional configuration; as well as The UE releases the conditional configuration in response to the indication.

11. The method according to claim 10, wherein, Receiving an instruction to unconditionally execute an immediate procedure and release the conditional configuration includes: receiving a message from the source base station, the message including an instruction to initiate the immediate procedure and including an implicit release indicator instructing the UE to release the conditional configuration.

12. The method according to claim 11, wherein, Receiving the instruction includes receiving a handover command from the source base station.

13. The method according to claim 11, wherein, Receiving the instruction includes receiving a Radio Resource Control (RRC) reconfiguration message that includes information related to a new SN or a new PScell.

14. The method according to claim 11, wherein, Releasing the conditional configuration includes releasing the measurement configuration.

15. A user equipment (UE) comprising processing hardware and configured to perform the method according to any one of claims 10 to 14.

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