Managing contiguous condition cell changes and related configurations

Abstract

A first node of a radio access network (RAN) sends (304) to a second node a request to operate as a secondary node (SN) and to provide dual connectivity (DC) to a user equipment (UE), where the first node operates as a primary node (MN), the request comprising an indication of continuous condition secondary cell addition or change (CPAC); receiving (306) a first conditional SN (C-SN) configuration from the second node in response to the request; and transmitting (308) the first conditional SN configuration and a second conditional SN configuration related to at least one cell not associated with the second node to the UE.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of the filing date of Provisional U.S. Patent Application No. 63 / 480,950, entitled “Managing Continuous Conditional Cell Changes and Related Configurations,” filed on January 20, 2023. The entire contents of that provisional application are hereby expressly incorporated herein by reference. Technical Field

[0003] The present disclosure relates generally to wireless communications and, more particularly, to managing conditional configuration to enable continuous conditional cell changes. Background Art

[0004] This background description is provided for the purpose of generally presenting the context of the present disclosure. The work of the presently named inventors, to the extent that it is described in this background section, and aspects of the specification that might not have been considered prior art at the time of filing are neither explicitly nor implicitly admitted to be prior art with respect to the present disclosure.

[0005] In a telecommunications system, a user equipment (UE) can sometimes concurrently utilize resources of multiple radio access network (RAN) nodes (such as components of a base station or a distributed base station) interconnected by a backhaul. When these network nodes support different radio access technologies (RATs), this type of connection is called multi-radio dual connectivity (MR-DC). When the UE operates in MR-DC, one base station operates as a master node (MN) covering a primary cell (PCell), and the other base station operates as a secondary node (SN) covering a primary secondary cell (PSCell). The UE communicates with the MN (via the PCell) and the SN (via the PSCell). In other scenarios, the UE transfers the wireless connection from one base station to another. For example, the serving base station may determine to hand over the UE to the target base station and initiate a handover process.

[0006] 3GPP specification TS 37.340 v16.6.0 describes the procedures for a UE to add or change a SN in a DC scenario. These procedures involve messaging (e.g., RRC signaling and preparation) between radio access network (RAN) nodes. This messaging generally results in latency, which in turn increases the probability that the SN add or SN change procedure will fail. These legacy procedures, which do not involve conditions checked at the UE, can be referred to as "immediate" SN add and SN change procedures.

[0007] Recently, "conditional" procedures (i.e., conditional SN or PSCell addition / change) have been considered for both SN or PSCell addition / change. Unlike the "immediate" procedures discussed above, these procedures do not add or change the SN or PSCell or perform handover until the UE determines that a condition is met. As used herein, the term "condition" can refer to a single detectable state or event (e.g., a particular signal quality metric exceeding a threshold), or to 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.).

[0008] To configure the conditional procedure, the RAN provides the UE with the conditions and a configuration (e.g., one or more random access preambles, etc.) that will enable the UE to communicate with an appropriate base station or via an appropriate cell when the conditions are met. For conditional addition of a base station as an SN or a candidate cell as a PSCell, for example, the RAN provides the UE with the conditions to be met before the UE can add the base station as an SN or the candidate cell as a PSCell, and a configuration that enables the UE to communicate with the base station or PSCell after the conditions have been met.

[0009] During an instant PSCell addition or change, the RAN (i.e., MN or SN) sends an RRC reconfiguration message to the UE, including multiple configuration parameters, and the UE attempts to connect to the (target) PSCell configured by the RRC reconfiguration message. After the UE successfully connects to the SN via the PSCell, the UE communicates with the SN on the PSCell using the multiple configuration parameters and security keys associated with the PSCell and derived from one or more security configuration parameters in the RRC reconfiguration message. The SN also derives security keys that match the security keys derived from the UE. After the UE successfully connects to the PSCell, the RAN (e.g., SN) communicates data with the UE using the matching security keys and the multiple configuration parameters.

[0010] In some cases, when, for example, multiple candidate PSCells are available, a candidate SN (C-SN) or target SN (T-SN) (these two terms are used interchangeably herein) provides multiple candidate configurations. When the mobile network completes preparations for a conditional SN procedure (e.g., conditional SN add or conditional SN cell change), the mobile network cannot determine which candidate secondary cell the UE will connect to in the future. Furthermore, since the UE only connects to a secondary cell when one or more conditions are met, the mobile network cannot even determine whether the UE will connect to any of the candidate cells in the future.

[0011] According to the 3GPP Release 17 Conditional PSCell Change (CPC) / Conditional PSCell Addition or Change (CPAC) procedure group, the RAN (e.g., MN or SN) can send multiple candidate configurations to the UE. However, when the UE determines that a trigger condition is met for a specific candidate configuration among the candidate configurations, the UE executes the specific candidate configuration and performs random access to the candidate PSCell configured in the specific candidate configuration. After completing random access to the candidate PSCell, the UE releases the configuration. Since the UE releases all candidate configurations, it cannot perform subsequent CPAC without receiving a new candidate configuration from the network.

[0012] Recently, 3GPP has proposed developing continuous CPAC (i.e., subsequent CPACs following a CPAC) that does not require new CPAC preparation from the network. "Continuous CPAC," also known as MR-DC with cell group selective activation, aims to reduce signaling overhead between the mobile network (MN) and the C-SN, as well as between the MN and the UE, and to reduce the disruption time associated with SCG changes. However, it remains unclear how the MN can ensure that the RAN and the UE communicate using the same candidate configuration when trigger conditions are met during continuous CPAC operation, nor how the MN should prepare the conditional configuration for continuous CPAC, particularly for multiple candidate SNs. Summary of the Invention

[0013] An example embodiment of the technology disclosed herein is a method implemented in a first node of a radio access network (RAN). The method includes: sending a request to a second node to operate as a secondary node (SN) and provide dual connectivity (DC) to a user equipment (UE), wherein the first node operates as a primary node (MN), the request including an indication of a continuous conditional secondary cell addition or change (CPAC); receiving a first conditional SN (C-SN) configuration from the second node in response to the request; and sending the first conditional SN configuration and a second conditional SN configuration related to at least one cell not associated with the second node to the UE.

[0014] Another example embodiment of these techniques is a method implemented in a first node of a RAN, the method comprising: sending, to a UE in DC communication with the first node as a mobile node (MN) and a second node of the RAN as a network node (SN), a C-SN configuration associated with a plurality of candidate cells for connection when one or more corresponding conditions are met, the plurality of candidate cells including a candidate cell of a candidate SN; receiving an indication that the UE is connected to the candidate cell; and sending a notification to the SN based on whether the C-SN is used for a continuous conditional cell change, the continuous conditional cell change being associated with the UE performing subsequent conditional cell changes based on the C-SN configuration.

[0015] Yet another example embodiment of these techniques is a node in a RAN, the node comprising a transceiver and configured to implement one of the above methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1A is a block diagram of an example system in which a base station and / or user equipment (UE) may implement the disclosed techniques for managing conditional procedures associated with a master node (MN) or a secondary node (SN);

[0017] Figure 1B is another block diagram of an example system in which a radio access network (RAN) and a user device may implement the techniques of this disclosure for managing conditional procedures associated with a MN or SN;

[0018] Figure 1C Yes, you can Figure 1A or Figure 1B A block diagram of an example base station including a central unit (CU) and a distributed unit (DU) operating in a system;

[0019] Figure 2 is a block diagram of an example protocol stack, according to which Figure 1A to Figure 1B The UE can communicate with the base station;

[0020] Figure 3A is a message passing diagram of an example scenario in which, to implement continuous CPAC, a MN receives and processes one or more SN configurations from a C-SN during a conditional SN add procedure;

[0021] Figure 3B is a message passing diagram of an example scenario in which, to implement continuous CPAC, a MN receives and processes one or more SN configurations from a C-SN during a MN-initiated conditional SN change procedure;

[0022] Figure 3C is a message passing diagram of an example scenario in which, to achieve continuous CPAC, the MN receives and processes one or more SN configurations from the C-SN during an SN-initiated conditional SN change scenario;

[0023] Figure 4A is a message passing diagram of an example scenario in which the SN initiates intra-SN continuous CPAC via the MN;

[0024] Figure 4B is a message passing diagram for an example scenario in which the SN initiates intra-SN continuous CPAC without involving the MN;

[0025] Figures 5A to 5C is a flow chart of an example method for a MN to perform continuous CPAC with a candidate SN (C-SN);

[0026] 6A to 6D is a flow chart of an example method for a MN to perform a conditional SN procedure with a C-SN and handle a UE context at a source SN (S-SN);

[0027] Figure 7 is a flow chart of an example method for a C-SN to perform continuous CPAC with a MN and handle UE context;

[0028] Figure 8A and Figure 8B is a flow chart of an example method for a C-SN to perform a conditional SN procedure with a MN and handle a response to the MN; and

[0029] Figure 9 is a flow chart of an example method for a SN and a MN to perform a conditional SN procedure. DETAILED DESCRIPTION

[0030] As discussed in detail below, the UE and / or one or more base stations manage conditional procedures, such as Conditional PSCell Addition or Change (CPAC). This disclosure may also use the acronyms CPA and CPC to separately refer to the Conditional PSCell Addition Procedure and the Conditional PSCell Change Procedure, respectively.

[0031] First reference Figure 1A , the example wireless communication system 100 includes a UE 102, a base station (BS) 104A, a base station 106A, and a core network (CN) 110. The base stations 104A and 106A may operate in a RAN 105 connected to the same core network (CN) 110. For example, the CN 110 may be implemented as an evolved packet core (EPC) 111 or a fifth generation (5G) core (5GC) 160.

[0032] Among other components, the EPC 111 may also include a serving gateway (SGW) 112, a mobility management entity (MME) 114, and a packet data network gateway (PGW) 116. The SGW 112 is generally configured to deliver user plane packets related to audio calls, video calls, Internet services, etc., and the MME 114 is configured to manage authentication, registration, paging, and other related functions. The PGW 116 provides connectivity from the UE to one or more external packet data networks (e.g., an Internet network and / or an Internet Protocol (IP) Multimedia Subsystem (IMS) network). The 5GC 160 includes a user plane function (UPF) 162, an access and mobility management function (AMF) 164, and / or a session management function (SMF) 166. Generally speaking, UPF 162 is configured to deliver user plane packets associated with audio calls, video calls, Internet services, etc.; AMF 164 is configured to manage authentication, registration, paging and other related functions; and SMF 166 is configured to manage PDU sessions.

[0033] like Figure 1A As shown, base station 104A supports cell 124A, and base station 106A supports cell 126A. In addition, each of base stations 104A, 106A can support more than one cell. For example, base station 106A can also support cell 126C. Cells 124A and 126A can partially overlap, so that UE 102 can communicate in DC with base station 104A and base station 106A operating as a master node (MN) and a secondary node (SN), respectively. In order to directly exchange messages during the DC scenario and other scenarios discussed below, MN 104A and SN 106A can support X2 or Xn interface. In general, CN 110 can be connected to any suitable number of base stations that support NR cells and / or EUTRA cells. Figure 1B An example configuration in which EPC 110 is connected to additional base stations is discussed.

[0034] The base station 104A is equipped with processing hardware 130, which may include one or more general-purpose processors (such as CPUs) and non-transitory computer-readable memory storing machine-readable instructions executable on the one or more general-purpose processors, and / or a dedicated processing unit. In an example implementation, the processing hardware 130 includes a conditional configuration controller 132 that is configured to manage conditional configuration for one or more conditional procedures (such as conditional handover (CHO), conditional PSCell addition or change (CPAC), or conditional SN addition or change (CSAC)) when the base station 104A operates as a MN.

[0035] The base station 106A is equipped with processing hardware 140, which may also include one or more general-purpose processors (such as CPUs) and non-transitory computer-readable memory storing machine-readable instructions executable on the one or more general-purpose processors, and / or a dedicated processing unit. In an example implementation, the processing hardware 140 includes a conditional configuration controller 142 that is configured to manage conditional configurations for one or more conditional processes (such as CHO, CPAC, or CSAC) when the base station 106A operates as an SN.

[0036] Still refer to Figure 1A UE 102 is equipped with processing hardware 150, which may include one or more general-purpose processors (such as CPUs) and non-transitory computer-readable memory storing machine-readable instructions executable on the one or more general-purpose processors, and / or special-purpose processing units. In an example implementation, the processing hardware 150 includes a UE condition configuration controller 152, which is configured to manage conditional configuration for one or more conditional processes.

[0037] More particularly, conditional configuration controllers 132, 142, and 152 may implement at least some of the techniques discussed below with reference to the message passing diagrams and flow charts. Figure 1A Conditional configuration controllers 132 and 142 are shown as separate components, but in at least some scenarios, base stations 104A and 106A may have similar implementations and operate as MN or SN nodes in different scenarios. In these implementations, each of base stations 104A and 106A may implement both conditional configuration controller 132 and conditional configuration controller 142 to support MN and SN functionality, respectively.

[0038] In operation, UE 102 may use radio bearers (e.g., DRBs or SRBs) that terminate at different times at MN 104A or SN 106A. UE 102 may apply one or more security keys when communicating on the radio bearers in the uplink (from UE 102 to BS) and / or downlink (from base station to UE 102) directions. In some cases, the UE may use different RATs to communicate with base stations 104A and 106A. Although the following examples may specifically relate to a particular RAT type (5G NR or EUTRA), generally, the techniques of this disclosure may also be applied to other suitable radio access and / or core network technologies.

[0039] Figure 1BDepicted are additional base stations 104B and 106B that may be included in wireless communication system 100. UE 102 initially connects to base station 104A. BSs 104B and 106B may have similar processing hardware as base station 106A. UE 102 initially connects to base station 104A.

[0040] In some scenarios, base station 104A may perform an on-the-fly SN addition to configure UE 102 to operate in dual connectivity (DC) with base station 104A (via PCell) and base station 106A (via PSCell other than cell 126A). Base stations 104A and 106A operate as the MN and SN, respectively, of UE 102. In some cases, UE 102 may operate in MR-DC connection mode, for example, communicating with base station 104A using 5G NR and communicating with base station 106A using EUTRA, or communicating with base station 104A using EUTRA and communicating with base station 106A using 5G NR. Multi-connectivity coordination may help the two base stations coordinate shared UE capabilities, including operating frequencies (e.g., band combinations, frequency ranges), UE measurements and reporting (e.g., intra-frequency measurements, inter-frequency measurements, inter-RAT measurements, measurement gaps), receive timing (e.g., DRX configuration, offset timing), and uplink power control (e.g., power headroom, maximum transmit power).

[0041] At a certain point in time, when UE 102 is communicating with MN 104A and S-SN 106A in DC, MN 104A may perform an immediate SN change to change the SN of UE 102 from base station 106A (source SN or "S-SN") to base station 104B (target SN or "T-SN"). In another scenario, SN 106A may perform an immediate PSCell change to change the PSCell of UE 102 to cell 126A. In one implementation, SN 106A may send a configuration to change the PSCell to cell 126A to UE 102 via a signaling radio bearer (SRB) (e.g., SRB3) for the immediate PSCell change. In another implementation, SN 106A may send a configuration to change the PSCell to cell 126A to UE 102 via MN 104A for the immediate PSCell change. MN 104A may send a configuration to UE 102 via SRB1 to immediately change the PSCell to cell 126A. Extended multi-connectivity coordination may help newly added base stations coordinate shared UE capabilities.

[0042] In other scenarios, base station 104A may perform a conditional SN addition procedure to first configure base station 106B as the C-SN of UE 102, i.e., conditional SN addition or change (CSAC). At this time, UE 102 may be in single connectivity (SC) with base station 104A, or in direct connectivity with base station 104A and base station 106A. If UE 102 is in direct connectivity with base station 104A and base station 106A, MN 104A may determine to perform the conditional SN addition procedure in response to a request received from base station 106A or in response to one or more measurement results received from UE 102 (e.g., extracted from a UE measurement report) or obtained by MN 104A based on measurements of signals received from UE 102 (e.g., sounding reference signal (SRS) or uplink demodulation reference signal (DMRS)). In contrast to the immediate SN addition scenario discussed above, UE 102 does not immediately attempt to connect to C-SN 106B. In this scenario, base station 104A again operates as a MN, but base station 106B initially operates as a C-SN instead of a SN.

[0043] More specifically, when UE 102 receives the configuration for C-SN 106B, UE 102 does not connect to C-SN 106B until UE 102 has determined that a certain condition is met (in some cases, UE 102 may consider multiple conditions, but for convenience, the following discussion only refers to a single condition). Multi-connectivity coordination is not necessary before the condition is met; however, it is helpful once the C-SN becomes connected. When UE 102 determines that the condition has been met, UE 102 connects to C-SN 106B, causing C-SN 106B to begin operating as SN 106B for UE 102. Therefore, although base station 106B operates as a C-SN rather than an SN, base station 106B is not yet connected to UE 102 and, therefore, is not yet serving UE 102. In some implementations, UE 102 may disconnect from SN 106A to connect to C-SN 106B.

[0044] In yet other scenarios, UE 102 communicates with MN 104A (via PCell) and SN 106A (via a cell other than cell 126A and Figure 1A104A is in DC. SN 106A may perform a conditional PSCell addition or change (CPAC) to configure a candidate PSCell (C-PSCell) 126A for UE 102. If UE 102 is configured with a signaling radio bearer (SRB) (e.g., SRB3) to exchange RRC messages with SN 106A, SN 106A may send a configuration for C-PSCell 126A to UE 102 via the SRB, for example, in response to one or more measurement results, which may be received from UE 102 via the SRB or via MN 104A or may be obtained by SN 106A based on measurements of signals received from UE 102. In the case of receiving the configuration via MN 104A, MN 104A receives the configuration for C-PSCell 126A. In contrast to the immediate PSCell change scenario discussed above, the UE 102 is not immediately disconnected from the PSCell and does not attempt to connect to the C-PSCell 126A.

[0045] More specifically, when the UE 102 receives the configuration for the C-PSCell 126A, the UE 102 does not connect to the C-PSCell 126A until the UE 102 has determined that a certain condition is met (in some cases, the UE 102 may consider multiple conditions, but for convenience, the following discussion only relates to a single condition). When the UE 102 determines that the condition has been met, the UE 102 connects to the C-PSCell 126A, causing the C-PSCell 126A to begin operating as the C-PSCell 126A for the UE 102. Thus, although the cell 126A operates as a C-PSCell rather than a PSCell, the SN 106A may not yet be connected to the UE 102 via the cell 126A. In some implementations, the UE 102 may disconnect from the PSCell to connect to the C-PSCell 126A.

[0046] In some scenarios, a condition associated with CSAC or CPAC may be that the signal strength / quality detected by the UE 102 on the C-PSCell 126A of the SN 106A or on the C-PSCell 126B of the C-SN 106B exceeds a certain threshold or otherwise corresponds to an acceptable measurement. For example, when one or more measurement results obtained by the UE 102 on the C-PSCell 126A are above a threshold configured by the MN 104A or the SN 106A or above a predetermined or preconfigured threshold, the UE 102 determines that the condition is met. When the UE 102 determines that the signal strength / quality on the C-PSCell 126A of the SN 106A is sufficiently good (again, measured relative to one or more quantitative thresholds or other quantitative metrics), the UE 102 may perform a random access procedure with the SN 106A on the C-PSCell 126A to connect to the SN 106A. After UE 102 successfully completes the random access procedure on C-PSCell 126A, C-PSCell 126A becomes PSCell 126A for UE 102. SN 106A can then begin data communications (user plane data or control plane data) with UE 102 via PSCell 126A. In another example, UE 102 determines that the condition is met when one or more measurement results obtained by UE 102 on C-PSCell 126B are above a threshold configured by MN 104A or C-SN 106B or above a predetermined or preconfigured threshold. When UE 102 determines that the signal strength / quality on C-PSCell 126B of C-SN 106B is sufficiently good (again, measured relative to one or more quantitative thresholds or other quantitative metrics), UE 102 can perform a random access procedure on C-PSCell 126B with C-SN 106B to connect to C-SN 106B. After UE 102 successfully completes the random access procedure on C-PSCell 126B, C-PSCell 126B becomes PSCell 126B for UE 102 and C-SN 106B becomes SN 106B. SN 106B can then begin data communications (user plane data or control plane data) with UE 102 via PSCell 126B.

[0047] In various configurations of the wireless communication system 100, base station 104A can be implemented as a master eNB (MeNB) or a master gNB (MgNB), and base stations 106A or 106B can be implemented as a secondary gNB (SgNB) or a candidate SgNB (C-SgNB). UE 102 can communicate with base station 104A and base stations 106A or 106B (106A / B) via the same RAT (such as EUTRA or NR) or different RATs. When base station 104A is a MeNB and base station 106A is an SgNB, UE 102 can be in EUTRA-NR DC (EN-DC) with the MeNB and the SgNB. In this scenario, MeNB 104A can configure base station 106B as the C-SgNB for UE 102. In this scenario, SgNB 106A can configure cell 126A as the C-PSCell 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 SC with the MeNB. In this scenario, MeNB 104A can configure base station 106B as another C-SgNB for UE 102.

[0048] In some cases, the MeNB, SeNB, or C-SgNB is implemented as an ng-eNB instead of an eNB. When base station 104A is a master ng-eNB (Mng-eNB) and base station 106A is an SgNB, UE 102 can be in Next Generation (NG) EUTRA-NR DC (NGEN-DC) with the Mng-eNB and the SgNB. In this scenario, MeNB 104A can configure base station 106B as the C-SgNB for UE 102. In this scenario, SgNB 106A can configure cell 126A as the C-PSCell for UE 102. When base station 104A is a Mng-NB and base station 106A is the C-SgNB for UE 102, UE 102 can be in SC with the Mng-NB. In this scenario, Mng-eNB 104A can configure base station 106B as another C-SgNB for UE 102.

[0049] When base station 104A is a MgNB and base stations 106A / B are SgNBs, UE 102 can be in NR-NR DC (NR-DC) with the MgNB and SgNB. In this scenario, MeNB 104A, in some cases, configures base station 106B as a C-SgNB for UE 102. In this scenario, SgNB 106A can configure cell 126A as a C-PSCell 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 SC with the MgNB. In this scenario, MgNB 104A can configure base station 106B as another C-SgNB for UE 102.

[0050] When base station 104A is a MgNB and base station 106A / B is a secondary ng-eNB (Sng-eNB), UE 102 can be in NR-EUTRA DC (NE-DC) with the MgNB and the Sng-eNB. In this scenario, MgNB 104A can configure base station 106B as a C-Sng-eNB for UE 102. In this scenario, Sng-eNB 106A can configure cell 126A as a C-PSCell 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 SC with the MgNB. In this scenario, MgNB 104A can configure base station 106B as another C-Sng-eNB for UE 102.

[0051] The base stations 104A, 106A, and 106B may be connected to the same core network (CN) 110, which may be an evolved packet core (EPC) 111 or a fifth generation core (5GC) 160. The base station 104A may be implemented as an eNB supporting an S1 interface for communication with the EPC 111, an ng-eNB supporting an NG interface for communication with the 5GC 160, or a base station supporting an NR radio interface and an NG interface for communication with the 5GC 160. The base station 106A may be implemented as an EN-DC gNB (en-gNB) having an S1 interface to the EPC 111, an en-gNB not connected to the EPC 111, a gNB supporting an NR radio interface and an NG interface to the 5GC 160, or an ng-eNB supporting an EUTRA radio interface and an NG interface to the 5GC 160. To directly exchange messages during the scenarios discussed below, base stations 104A, 106A, and 106B may support an X2 or Xn interface.

[0052] like Figure 1BAs shown, base station 104A supports cell 124A, base station 104B supports cell 124B, base station 106A supports cell 126A, and base station 106B supports cell 126B. Cells 124A and 126A may partially overlap, and cells 124A and 124B may also partially overlap, so that UE 102 can communicate with base station 104A (operating as a MN) and base station 106A (operating as a SN) in DC mode, and after completing an SN change, communicate with base station 104A (operating as a MN) and SN 104B in DC mode. More specifically, when UE 102 operates in DC mode with base station 104A and base station 106A, base station 104A operates as a MeNB, Mng-eNB, or MgNB, and base station 106A operates as an SgNB or Sng-eNB. Cells 124A and 126B may partially overlap. When UE 102 is in SC with base station 104A, base station 104A operates as a MeNB, Mng-eNB, or MgNB, and base station 106B operates as a C-SgNB or C-Sng-eNB. When UE 102 is in DC with base station 104A and base station 106A, base station 104A operates as a MeNB, Mng-eNB, or MgNB, base station 106A operates as an SgNB or Sng-eNB, and base station 106B operates as a C-SgNB or C-Sng-eNB.

[0053] In general, the wireless communication network 100 may include any suitable number of base stations supporting NR cells and / or EUTRA cells. More specifically, the EPC 111 or the 5GC 160 may be connected to any suitable number of base stations supporting NR cells and / or EUTRA cells. Although the following examples specifically relate to specific CN types (EPC, 5GC) and RAT types (5G NR and EUTRA), in general, the techniques of the present disclosure may also be applied to other suitable radio access and / or core network technologies, such as sixth generation (6G) radio access and / or 6G core network or 5G NR-6G DC.

[0054] Figure 1CAn example distributed implementation of a base station, such as base station 104A, 104B, 106A, or 106B, is depicted. In this implementation, the base station may include a central unit (CU) 172 and one or more distributed units (DUs) 174. CU 172 is equipped with processing hardware, which may include one or more general-purpose processors (such as CPUs) and non-transitory computer-readable memory storing machine-readable instructions executable on the one or more general-purpose processors, and / or dedicated processing units. In one example, CU 172 is equipped with processing hardware 130. In another example, CU 172 is equipped with processing hardware 140. In an example implementation, processing hardware 140 includes a (C-)SN RRC controller configured to manage or control one or more RRC configurations and / or RRC procedures when base station 106A operates as an SN or a candidate SN (C-SN). Base station 106B may have the same or similar hardware as base station 106A. The DU 174 is also equipped with processing hardware, which may include one or more general-purpose processors (such as CPUs) and non-transitory computer-readable memory storing machine-readable instructions that can be executed on the one or more general-purpose processors, and / or dedicated processing units. In some examples, in an example implementation, the processing hardware includes: a medium access control (MAC) controller configured to manage or control one or more MAC operations or procedures (e.g., random access procedures); and a radio link control (RLC) controller configured to manage or control one or more RLC operations or procedures when the base station 106A operates as an MN, SN, or candidate SN (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.

[0055] Figure 2 An example protocol stack 200 is shown in simplified form according to which a UE 102 may communicate with an eNB / ng-eNB or gNB (e.g., one or more of base stations 104, 106).

[0056] In the example stack 200, the EUTRA physical layer (PHY) 202A provides transport channels to the EUTRA MAC sublayer 204A, which in turn provides logical channels to the EUTRA RLC sublayer 206A. The EUTRA RLC sublayer 206A in turn provides RLC channels to the EUTRA PDCP sublayer 208 and, in some cases, to the NR PDCP sublayer 210. Similarly, the NRRPHY 202B provides transport channels to the NR MAC sublayer 204B, which in turn provides logical channels to the NR RLC sublayer 206B. The NR RLC sublayer 206B in turn provides data delivery services to the NR PDCP sublayer 210. The NR PDCP sublayer 210 can then provide data delivery services to the Service Data Adaptation Protocol (SDAP) 212 or the Radio Resource Control (RRC) sublayer ( Figure 2 In some implementations, the UE 102 supports both EUTRA and NR stacks, such as Figure 2 As shown, to support switching between EUTRA and NR base stations and / or support DC through EUTRA and NR interfaces. Figure 2 As shown, the UE 102 may support NR PDCP 210 layered on top of the EUTRA RLC 206A, and the SDAP sublayer 212 layered on top of the NR PDCP sublayer 210.

[0057] The EUTRA PDCP sublayer 208 and the NR PDCP sublayer 210 receive packets, which may be referred to as service data units (SDUs) (e.g., from an Internet Protocol (IP) layer layered directly or indirectly on the PDCP layer 208 or 210), and output packets, which may be referred to as protocol data units (PDUs) (e.g., to the RLC layer 206A or 206B). For simplicity, this disclosure refers to both SDUs and PDUs as "packets," except where the distinction between SDUs and PDUs is important.

[0058] On the control plane, the EUTRA PDCP sublayer 208 and the NR PDCP sublayer 210 may provide signaling radio bearers (SRBs) or RRC sublayers ( Figure 2 The EUTRA PDCP sublayer 208 and the NR PDCP sublayer 210 may exchange data (e.g., RRC messages or non-access stratum (NAS) messages) on the user plane. The EUTRA PDCP sublayer 208 and the NR PDCP sublayer 210 may provide data radio bearers (DRBs) to support data exchange. The data exchanged on the NR PDCP sublayer 210 may be SDAP PDUs, Internet Protocol (IP) packets, or Ethernet packets.

[0059] Next, refer to Figures 3A to 3C and Figures 4A to 4B Let's discuss several example scenarios where the UE and / or RAN performs the disclosed techniques for supporting conditional procedures. Figures 3A to 3C and Figures 4A to 4B Similar events in FIG. 5 are labeled with the same reference numerals, and the differences are discussed below where appropriate.

[0060] First reference Figure 3A In scenario 300A, base station 104A operates as a MN and base station 106A operates as a C-SN. In this scenario, MN 104A receives and processes one or more C-SN configurations from C-SN 106A during the conditional SN addition procedure. Initially, UE 102 operates 302 with MN 104A in single connectivity (SC). While in SC, UE 102 transmits UL PDUs and / or DL ​​PDUs with MN 104A (e.g., via PCell 124A) according to the MN configuration.

[0061] Later, MN 104A determines to configure base station 106A as the C-SN of UE 102 for conditional PSCell addition (CPA). For example, MN 104A may make this determination based on measurement results from UE 102. In some implementations, UE 102 performs measurements and sends the measurement results according to the measurement configuration configured by MN 104A. In some implementations, MN 104A may detect or estimate that UE 102 is moving toward the coverage area (i.e., one or more cells) of base station 106A based on uplink signals received from UE 102 or positioning measurement results received from UE 102. In response to this determination, MN 104A sends 304 an SN Addition Request message including a first indication for continuous CPAC (e.g., a Selective Activation Indication IE) to C-SN 106A. As used in this disclosure, continuous CPAC may also be referred to as MR-DC with cell group selective activation.

[0062] In some implementations, the MN 104A includes conditional PSCell Addition (CPA) information (e.g., a Conditional PSCell Addition Information Request IE) in the SN Addition Request message. In one implementation, the Conditional PSCell Addition Information Request IE includes a Maximum Number of PSCells to Prepare IE / field. In some implementations, the MN 104A includes the first indication in the Conditional PSCell Addition Information Request IE. In other implementations, the MN 104A includes the first indication and the Conditional PSCell Addition Information Request IE as different IEs (e.g., XnAP or X2AP IEs) in the SN Addition Request message.

[0063] In some implementations, the MN 104A generates candidate cell information (e.g., CandidateCellInfoListMN) including measurement results for one or more cells and includes the candidate cell information in an SN Add Request message. In some implementations, the MN 104A determines SN restriction information for limiting (the values ​​of) configuration parameters that the C-SN 106A can configure for the UE 102, and includes the SN restriction information in the SN Add Request message. In some implementations, the MN 104A includes the candidate cell information and / or SN restriction information in an inter-node RRC message (i.e., a CG-ConfigInfo IE) and includes the inter-node RRC message in the SN Add Request message. Alternatively, the MN 104A includes the SN restriction information outside of the CG-ConfigInfo in the SN Add Request message. When determining the SN restriction information, the MN 104A may determine MN restriction information for limiting (the values ​​of) configuration parameters that the MN 104A can configure for the UE 102. In some implementations, the MN 104A includes CPA information in the SN Add Request message. For example, the CPA information (eg, the conditional PSCell add information request IE) includes an IE indicating the maximum number of PSCells that the C-SN 106A can prepare.

[0064] In some implementations, the MN 104A includes a reference C-SN configuration in the SN Add Request message for the purpose of continuous CPAC. The MN 104A may obtain the reference C-SN configuration (e.g., C-SN configuration 0) from the C-SN (e.g., C-SN 0). Alternatively, the MN 104A may be pre-configured with the reference C-SN configuration. As another alternative, the MN 104A generates the reference C-SN configuration. In other implementations, when the MN 104A decides to perform CPA with the C-SN 106A and no reference C-SN configuration is available, the MN 104A avoids including the reference C-SN configuration in the SN Add Request message.

[0065] In response to receiving 304 the SN Add Request message with the CPAC indication and / or the first indication and / or the reference C-SN configuration, C-SN 106A determines M1 C-PSCells (where M1 is a positive integer) and generates an inter-node message (e.g., CG-CandidateList) to include C-SN configurations 1, ..., M1 for UE 102, where each C-SN configuration is associated with a specific C-PSCell among the M1 C-PSCells (i.e., C-PSCell 1, ..., M1). For example, the C-PSCells include cell 126A and / or cell 126C. In some implementations, M1 is not greater than the maximum number of PSCells that can be received in the SN Add Request message or determined by C-SN 106A. In some implementations, C-SN 106A determines the C-PSCells and C-SN configurations 1, ..., M1 based on candidate cell information and SN restriction information. The inter-node message includes an addition list of CG-CandidateInfo IEs (e.g., cg-CandidateToAddModList), where each CG-CandidateInfo IE corresponds to a C-PSCell. Each CG-CandidateInfo IE in the addition list includes a CG-CandidateInfo ID (e.g., cg-CandidateInfoId or CG-CandidateInfoId including C-PSCell information (e.g., SSB frequency information (e.g., ARFCN-ValueNR)) and physical cell ID (PCI) of the C-PSCell) and a CG-Config IE. Each CG-Config IE includes the C-SN configuration of the corresponding C-PSCell, and optional parameters for allowing MN 104A to prepare the corresponding MN configuration to coordinate with the C-SN configuration when necessary. The CG-CandidateInfo ID can be used by C-SN 106A and MN 104A to manage the CG-CandidateInfo IEs in the addition list. In some implementations, the MN 104A uses the first indication to indicate to the C-SN 106A that, unlike conventional or 3GPP Release 17 CPAC procedures, the UE 102 will not release the prepared C-SN configuration when the UE 102 accesses one of the C-SN configurations from the C-SN 106A or another C-SN.

[0066] In response to the SN Add Request message, the C-SN 106A sends 306 an SN Add Request Confirm message to the MN 104A. The SN Add Request Confirm message includes: a CG-CandidateList; and / or a Conditional PSCell Add Information Confirm IE including a list of accepted candidate cells (CGIs). The C-SN 106A includes the M1 C-SN configurations in the CG-CandidateList. In some implementations, the C-SN 106A includes a reference C-SN configuration (e.g., Ref C-SN-config) in the SN Add Request Confirm message for use by the MN 104A in preparing CPAC with other C-SNs of the UE 102, as described below. In some implementations, the C-SN 106A includes the reference C-SN configuration and the CG-CandidateList in separate IEs (e.g., XnAP or X2AP IEs) in the SN Add Request Confirm message. In other implementations, the C-SN 106A includes the reference C-SN configuration in the CG-CandidateList IE.

[0067] In some implementations, MN 104A includes an indication requesting a reference C-SN configuration. In response to this indication, C-SN 106A includes the reference C-SN configuration in the SN Add Request Confirmation message. This indication can be an IE such as a query IE (e.g., a reference C-SN configuration query), a reference configuration request IE, or a reference configuration indication IE. In some implementations, each of the M1 C-SN configurations is an incremental configuration that enhances the reference C-SN configuration. In other words, the M1 C-SN configurations are associated with the reference C-SN configuration. In other implementations, C-SN 106A refrains from including the reference C-SN configuration in the SN Add Request Confirmation message.

[0068] After receiving 306 the SN Add Request Confirm message including the CG-CandidateList, the MN 104A may assign a specific configuration ID (e.g., condReconfigId or CondReconfigurationId) to each of the C-SN configurations in the CG-Config IE. For example, if the CG-Config IEs 1, ..., M1 include C-SN configurations 1, ..., M1, the MN 104A may assign configuration IDs 1, ..., M1 to the C-SN configurations 1, ..., M1, respectively. The MN 104A may generate trigger condition configurations (e.g., condExecutionCond fields / IEs) for the C-SN configurations 1, ..., M1, respectively. Each of the trigger condition configurations may configure one or more conditions that trigger the UE 102 to connect to the C-SN 106A via a specific C-PSCell configured in the specific C-SN configuration. The MN 104A may generate corresponding MN configurations 1, ..., M1 based on the parameters received in the CG-Config IEs 1, ..., M1 to coordinate with the C-SN configurations 1, ..., M1, respectively. In some implementations, the MN 104A may generate MN messages or RRC container messages (e.g., RRCConnectionReconfiguration messages or RRCReconfiguration messages) 1, ..., M1, respectively including the C-SN configurations and / or the corresponding MN configurations 1, ..., M1. The MN 104A generates the condRRCReconfig fields / IEs 1, ..., M1 to include the MN messages or RRC container messages 1, ..., M1, respectively. MN 104A generates conditional (re)configuration fields / IEs (e.g., CondReconfigToAddMod fields / IEs) 1, ..., M1, respectively including condRRCReconfig fields / IEs 1, ..., M1, configuration IDs (e.g., condReconfigId) 1, ..., M1, and triggering condition configurations (e.g., condExecutionCond) 1, ..., M1.

[0069] MN 104A sends 308 an RRC reconfiguration message to UE 102 that includes conditional (re)configuration fields / IEs 1, ..., M1. For example, the RRC reconfiguration message is an RRCConnectionReconfiguration message or an RRCReconfiguration message. In some implementations, MN 104A generates a first list (e.g., CondReconfigToAddModList) of conditional (re)configuration fields / IEs (e.g., CondReconfigToAddMod). MN 104A sends 308 an RRC reconfiguration message to UE 102 that includes the first list.

[0070] In some implementations, the MN 104A includes the reference C-SN configuration in the RRC reconfiguration message in event 308. In other implementations, the MN 104A includes the reference C-SN configuration in a separate RRC reconfiguration message in addition to the RRC reconfiguration message in event 308 and sends the separate RRC reconfiguration message to the UE 102. In some implementations, the MN 104A includes the reference C-SN configuration in the first list. In other implementations, the MN 104A does not include the reference C-SN configuration in the first list but includes it in a separate field / IE in the RRC reconfiguration message in event 308. In response, the UE 102 sends 312 an RRC reconfiguration complete message (e.g., an RRCConnectionReconfigurationComplete message or an RRCReconfigurationComplete message) to the MN 104A. Events 308 and 312 together define the RRC reconfiguration procedure 310.

[0071] In some implementations, based on determining that continuous CPAC is to be performed, MN 104A determines to configure an additional N-1 C-SNs for UE 102, where N is a positive integer greater than 1. In such a case, C-SN 106A is the first C-SN (i.e., C-SN 1) among the total N C-SNs. The interactions between MN 104A and C-SNs 2, ..., N are similar to the interactions between MN 104A and C-SN 1 described above for events 304, 306, 308, and 310. If, as described above, C-SN 1 (i.e., C-SN 106A) includes a reference C-SN configuration in the SN add request confirm message 306 to MN 104A, MN 104A may include the reference C-SN configuration in the SN add request messages that MN 104A sends to C-SNs 2, ..., N, respectively. Thus, each of C-SNs 2, ..., N generates a C-SN configuration based on the reference C-SN configuration. In some implementations, each of the C-SN configurations is an incremental configuration that enhances a reference C-SN configuration.

[0072] In some implementations, for each of the N-1 C-SNs, the MN 104A performs an RRC reconfiguration procedure with the UE 102 similar to event 310. In other implementations, the MN 104A includes the C-SN configurations received from the N-1 C-SNs in the RRC reconfiguration message at event 308, similar to including C-SN configurations 1, ..., M1 as described above.

[0073] In some implementations, as discussed below, the MN 104A may manage C-SN configurations of N C-SNs from the UE 102, assuming there are M1 C-SN configurations from C-SN 1, M2 C-SN configurations from C-SN 2, ..., and M from C-SN N. N C-SN configuration, where M i is a positive integer and I is a number between 1 and N. For example, the MN 104A may assign configuration IDs 1, ..., M1 to M1 C-SN configurations (and corresponding MN configurations) from C-SN 1, configuration IDs (M1+1), ..., (M1+M2) to M2 C-SN configurations (and corresponding MN configurations) from C-SN 2, and configuration IDs (M1+M2+...+M1+M2) to M2 C-SN configurations (and corresponding MN configurations) from C-SN 2. N-1 +1),...,(M1+M2+...+M N ) assigned to M from C-SN N NC-SN configurations (and corresponding MN configurations). MN 104A sends (M1+M2+...+M N ) C-SN configurations (and corresponding MN configurations). For example, MN 104A sends C-SN configurations with configuration IDs 1, ..., M1 to UE 102 in a first CondReconfigToAddModList and sends C-SN configurations with configuration IDs (M1+1), ..., (M1+M2+ ... + M1) to UE 102 in a second CondReconfigToAddModList. N )’s C-SN configuration.

[0074] After receiving 312 the RRC reconfiguration complete message or an acknowledgement (e.g., an RLC acknowledgement or a hybrid automatic repeat request (HARQ) acknowledgement) for a PDU (e.g., an RLC PDU or a MAC PDU) including the RRC reconfiguration message 308, the MN 104A may (determine to) send 314 an Early Status Transfer message to the C-SN 106A and / or C-SNs 2, ..., N to transfer a COUNT value of first downlink SDUs forwarded by the MN 104A to the C-SN 106A and / or C-SNs 2, ..., N or a COUNT value of already forwarded downlink SDUs for each DRB discarded for the UE 102. The early status transfer message may be an Early Sequence Number (SN) Status Transfer message, where "SN" in this context refers to a sequence number rather than a secondary node. MN 104A may send 314 an early status transfer message without receiving an interface message indicating that UE 102 is connected to C-SN 106A and / or N-1 C-SNs.

[0075] UE 102 may use one or more conditions to determine whether to connect to one of the C-PSCells. If UE 102 detects 316 that a condition for connecting to a first C-PSCell (e.g., C-PSCell 1 of C-SN 106A) is met, UE 102 is connected to the first C-PSCell. That is, the condition (i.e., "trigger condition") triggers UE 102 to connect to the first C-PSCell or perform C-SN configuration on the first C-PSCell. However, if UE 102 does not detect that the condition is met, UE 102 is not connected to the first C-PSCell. In response to the detection, UE 102 initiates a random access procedure on the first C-PSCell. In response to the initiation, UE 102 performs 318 a random access procedure with C-SN 106A via the first C-PSCell (e.g., cell 126A). In response to the detection or initiation 316, UE 102 sends 320 an RRC reconfiguration complete message to MN 104A. The UE 102 may send 320 the RRC reconfiguration complete message before, during, or after the random access procedure.

[0076] In some implementations, the UE 102 may indicate in the RRC reconfiguration complete message that the UE 102 has performed a particular C-SN configuration by including a configuration ID corresponding to one of the C-SN configurations. If the MN 104A performs multiple CPA procedures with different C-SNs, the MN 104A may use the configuration ID to identify or determine the ID of the C-PSCell (e.g., the PCI and / or CGI of the C-PSCell 126A) and / or the ID of the C-SN. The MN 104A may also use the configuration ID to identify or determine the C-SN configuration or the CG-Config IE including the C-SN configuration.

[0077] In response to receiving 320 the RRC Reconfiguration Complete message or after receiving the RRC Reconfiguration Complete message, the MN 104A may send 322 an SN message to the C-SN 106A. In some implementations, the SN message may be an SgNB Reconfiguration Complete or S-Node Reconfiguration Complete message. In other implementations, the SN message may be an RRC Transfer message. In still other implementations, the SN message may be a new interface message defined in 3GPP 38.423 or 36.423 Release 17 or future specifications (e.g., an XnAP or X2AP message). In some implementations, the UE 102 may include an SN RRC message (e.g., an RRCReconfigurationComplete message) in the RRC Reconfiguration Complete message sent by the UE 102 at event 320. In such cases, the MN 104A may include the SN RRC message in the SN message.

[0078] In some implementations, the random access procedure may be a four-step random access procedure or a two-step random access procedure. In other implementations, the random access procedure may be a contention-based random access procedure or a contention-free random access procedure. For example, the UE 102 may include the RRC reconfiguration complete message in message 3 of the four-step random access procedure or in message A of the two-step random access procedure.

[0079] After the C-SN 106A successfully completes the random access procedure with the UE 102, the C-SN 106A may send 324 an interface message (e.g., an SN modification request message, an NG-RAN node configuration update message, an E-UTRA-NR cell resource coordination request message, or a success indication message) to the MN 104A. The interface message may include PSCell information of the PSCell (e.g., cell 126A) and / or corresponding CG-Config IE and / or coordination information for physical resource block (PRB) coordination (e.g., SgNB resource coordination information IE or MR-DC resource coordination information IE). The PSCell information may include a cell global identifier (CGI), a physical cell identifier (PCI), and / or an absolute radio frequency channel number (ARFCN) identifying the DL carrier frequency of the PSCell. In some implementations, the C-SN 106A may send 324 the interface message in response to or after receiving the SN message or performing the random access procedure 318. In some implementations, the interface message also includes SN restriction information. The MN 104A may use the SN restriction information to determine the MN restriction information.

[0080] In response to receiving 320 the RRC reconfiguration complete message or receiving 324 the interface message, or after receiving 320 the RRC reconfiguration complete message or receiving 324 the interface message, MN 104A applies 326 the corresponding conditional MN configuration. In response to applying 326 the corresponding conditional MN configuration, MN 104A may send 328 an RRC reconfiguration message including configuration parameters to UE 102. In some implementations, configuration parameters 328 may reconfigure or release (the values ​​of) configuration parameters used by UE 102 to communicate with MN 104A. In other implementations, configuration parameters 328 may be new configuration parameters used to configure UE 102 to communicate with MN 104A. In response to RRC reconfiguration message 328, UE 102 may send 330 an RRC reconfiguration complete message to MN 104A. In response, MN 104A may send 332 an SN modification confirmation message (e.g., an SgNB modification confirmation message or an S-node modification confirmation message).

[0081] In response to receiving 320 the RRC reconfiguration complete message or receiving 324 the interface message, or after receiving 320 the RRC reconfiguration complete message or receiving 324 the interface message, the MN 104A may send 334 an SN status transfer message to transfer the uplink PDCP SN and HFN receiver status and / or the downlink PDCP SN and HFN transmitter status for each of the DRBs of the UE 102. In contrast to event 314, the MN 104A sends 334 the (non-early) SN status transfer message.

[0082] After UE 102 successfully completes 318 the random access procedure, UE 102 communicates 336 with MN 104A according to the (updated) MN configuration and communicates 337 with C-SN 106A via the first C-PSCell according to the C-SN configuration configuring the first C-PSCell. Events 318, 320, 322, 324, 326, 328, 330, 332, 334, and 336 occur in the Figure 3A 394. Similar to event 316, UE 102 may later detect 338 that a condition for connecting to a second C-PSCell belonging to C-SN 106A is met. Therefore, similar to process 394, UE 102, MN 104A, and C-SN 106A may perform 395 a CPAC execution procedure for the second C-PSCell. If MN 104A is configured with an additional C-SN (e.g., C-SN 2), similar to event 316 or 338, UE 102 may later (or instead, before event 338) detect that a condition for connecting to a C-PSCell belonging to C-SN 2 is met. Therefore, similar to event 394 or 395, UE 102, MN 104A, and C-SN may perform a CPAC execution procedure for the C-PSCell of C-SN 2.

[0083] Continue to refer Figure 3A In some implementations, the C-SN configuration may be a complete and independent configuration (i.e., a full configuration). The C-SN configuration may include a full configuration indication (information element (IE) or field) identifying the C-SN configuration as a full configuration. In this case, the UE 102 may use the C-SN configuration to communicate with the SN 106A independently of the SN configuration. In other implementations, the C-SN configuration may include one or more configurations that are "delta" configurations or enhance the reference C-SN configuration. In these cases, the UE 102 may use the delta C-SN configuration together with the reference C-SN configuration to communicate with the C-SN 106A.

[0084] The C-SN configuration may include a plurality of configuration parameters for the UE 102 to apply when communicating with the SN 106A via the C-PSCell 126A. The plurality of configuration parameters may configure the C-PSCell 126A of the SN 106A and zero, one, or more candidate secondary cells (C-SCells) for the UE 102. The plurality of configuration parameters may configure radio resources for the UE 102 to communicate with the C-SN 106A via the C-PSCell 126A of the C-SN 106A and zero, one, or more C-SCells. The plurality of configuration parameters may configure zero, one, or more radio bearers. The one or more radio bearers may include SRBs and / or one or more DRBs.

[0085] In some implementations, the C-SN configuration may include a C-PSCell 126A that configures the C-SN 106A and a cell group configuration (CellGroupConfig) IE for zero, one, or more C-SCells. In one implementation, the C-SN configuration includes a radio bearer configuration. In another implementation, the C-SN configuration does not include a radio bearer configuration. For example, the radio bearer configuration may be a RadioBearerConfig IE, a DRB-ToAddModList IE or an SRB-ToAddModList IE, a DRB-ToAddMod IE, or an SRB-ToAddMod IE. In various implementations, the C-SN configuration may be an RRCReconfiguration message, an RRCReconfiguration-IE, or a CellGroupConfig IE in accordance with 3GPP TS 38.331. The full configuration indication may be a field or IE in accordance with 3GPP TS 38.331. In some implementations, the reference C-SN configuration may include a C-PSCell 126A that configures the C-SN 106A and a cell group configuration (CellGroupConfig) IE for zero, one, or more C-SCells. In one implementation, the reference C-SN configuration includes a radio bearer configuration. In another implementation, the reference C-SN configuration does not include a radio bearer configuration. In various implementations, the reference C-SN configuration may be an RRCReconfiguration message, an RRCReconfiguration-IE, or a CellGroupConfig IE in accordance with 3GPP Technical Specification (TS) 38.331. Alternatively, the reference C-SN configuration is a new field or IE in 3GPP Release 18 or later specifications (e.g., TS 38.331), including an RRCReconfiguration message, an RRCReconfiguration-IE, or a CellGroupConfig IE. The full configuration indication may be a field or IE in accordance with 3GPP TS 38.331.

[0086] In some implementations, the MN 104A determines that a reference C-SN configuration (i.e., the first reference C-SN configuration) is to be updated. In response to this determination, similar to process 310, the MN 104A sends a second reference C-SN configuration to the UE 102. If the second reference C-SN configuration is a full configuration, the UE 102 replaces the first reference C-SN configuration with the second reference C-SN configuration. If, similar to event 316 or 338, the conditions for connecting to the C-PSCell are met, similar to event 318 and events 336, 394, or 395, respectively, the UE 102 performs a random access procedure on the C-PSCell and applies the C-SN configuration (configuring the C-PSCell or associating with the C-PSCell) and the second reference C-SN configuration.

[0087] In the case where the reference C-SN configuration is an incremental configuration, UE 102 utilizes the second reference C-SN configuration to enhance the first reference C-SN configuration to obtain an updated reference C-SN configuration. Similar to event 316 or 338, if the conditions for connecting to the C-PSCell are met, similar to event 318 and events 336, 394, or 395, respectively, UE 102 performs a random access procedure on the C-PSCell and applies the C-SN configuration (configured C-PSCell or associated with the C-PSCell) and the updated reference C-SN configuration.

[0088] As described above, after UE 102 applies the C-SN configuration, the applied C-SN configuration becomes the SN configuration (i.e., the serving or source SN configuration) or part of the SN configuration. After applying the C-SN configuration (e.g., in response to applying the C-SN configuration), UE 102 avoids deleting the conditional (re)configuration field / IE associated with the reference C-SN configuration.

[0089] In some implementations, similar to events 304, 306, and 310, MN 104A obtains a C-SN configuration for a specific C-PSCell configured for non-contiguous CPAC (e.g., Release 17 CPAC) from the C-SN and sends the C-SN configuration to UE 102. In such cases, the C-SN configuration for non-contiguous CPAC is not associated with the reference C-SN configuration. If, similar to event 316 or 338, the conditions for connecting to a specific C-PSCell are met, similar to event 318 and events 336, 394, or 395, respectively, UE 102 performs a random access procedure on the specific C-PSCell and applies the C-SN configuration to communicate with the C-SN on the specific C-PSCell. After applying the C-SN configuration, UE 102 deletes the conditional (re)configuration field / IE.

[0090] In some implementations, trigger condition configuration 1 configures the evaluation and detection conditions for CPA in event 316. At event 308, UE 102 receives an additional trigger condition configuration for applying the C-SN configuration for CPC in event 336. After UE 102 detects that the conditions are met in event 316 or applies the C-SN configuration in event 336, UE 102 replaces trigger condition configuration 1 with the additional trigger condition configuration. When communicating with SN 106A in event 336, UE 102 evaluates whether the conditions configured in the additional trigger condition are met.

[0091] Figure 3B Depicts the Figure 3A A similar scenario 300B, i.e., MN-initiated conditional SN change for continuous CPC is described below. Figure 3B and Figure 3A The difference between.

[0092] UE 102 initially operates 301 with MN 104A and S-SN 106B in DC, and communicates with S-SN 106B via PSCell 126B according to a first SN configuration (i.e., current SN configuration, serving SN configuration, or source SN configuration). Later, MN 104A determines to perform a conditional SN change (preparation) procedure with C-SN 106A to achieve continuous CPC.

[0093] and Figure 3A Unlike scenario 300A in FIG3 (where the reference C-SN configuration can come from C-SN 0, MN 104A, or C-SN 1), in scenario 300B, MN 104A obtains the reference C-SN configuration from S-SN 106B. Specifically, MN 104A may send 340 an SN Modify Request message to S-SN 106B to query the reference C-SN configuration using a specific IE (e.g., SCG Configuration Query or a newly defined IE specifically for continuous CPAC, such as Reference C-SN Configuration Query). In response, S-SN 106B sends 342 an SN Modify Request Acknowledge message to MN 104A, including the reference C-SN configuration. In some implementations, the reference C-SN configuration is the first SN configuration. In other implementations, the reference C-SN configuration is different from the first SN configuration. In still other implementations, the reference C-SN configuration is a subset of the first SN configuration. In some implementations, the reference C-SN configuration is the full configuration. In other implementations, the reference C-SN configuration is an incremental configuration that enhances the first SN configuration.

[0094] Similar to event 304, MN 104A sends 305 an SN Add Request message to C-SN 106A, which includes the reference C-SN configuration obtained from S-SN 106B in event 342. In response, similar to event 306, C-SN 106A sends 307 an SN Add Request Confirm message to MN 104A, which includes M1 C-SN configurations based on the reference C-SN configuration. In some implementations, each of the M1 C-SN configurations is an incremental configuration that enhances the reference C-SN configuration from S-SN 106B. In some implementations, C-SN 106A refrains from including the reference C-SN configuration in the SN Add Request Confirm message in event 307. MN 104A performs 310 an RRC reconfiguration procedure with UE 102. If early data forwarding is required, the MN 104A may send 344 an interface message (e.g., an Xn-U address indication or a data address indication message) to the S-SN 106B. The S-SN 106B then sends 346 an early status transfer message to the MN 104A, and the MN 104A then sends 314 an early status transfer message to the C-SN 106A.

[0095] In some implementations, such as Figure 3A As described in , based on determining to perform continuous CPAC, MN 104A also determines to configure additional N-1 C-SNs for MN-initiated CPC. N is a positive integer greater than 1. The interactions between MN 104A, C-SN 2, ..., N, and UE 102 are similar to those described above for events 305, 307, and 310 and Figure 3A The interactions between MN 104A, C-SN 1 and UE 102 are similar to those described in .

[0096] and Figure 3ASimilarly, UE 102 later detects 316 that the conditions for connecting to the first C-PSCell are met, and in response to the detection, performs a random access procedure with C-SN 106A on the first C-PSCell. UE 102, MN 104A, and C-SN 106A perform a CPAC execution procedure 394. After (e.g., in response to) procedure 394, MN 104A sends 348 an SN release request message (e.g., an SgNB release request or an S-node release request message) for UE 102 to S-SN 106B. In response, S-SN 106B stops communicating with UE 102 and sends 350 an SN release request confirmation message (e.g., an SgNB release request confirmation or an S-node release request confirmation message) to MN 104A. In some implementations, if S-SN 106B has prepared the C-SN configuration for continuous CPAC, MN 104A may include an indicator or cause value in the SN Release Request message indicating that the SN release procedure involves continuous CPAC. Therefore, S-SN 106B does not anticipate a subsequent UE context release procedure from MN 104A (i.e., MN 104A does not send a UE Context Release message to S-SN 106B after the SN Release Request message). Upon receiving the SN Release Request message, indicator, or cause value, S-SN 106B maintains the UE context of UE 102 and / or the UE-associated signaling connection between MN 104A and S-SN 106B. In the event that data forwarding is required, MN 104A may send a 351 interface message (e.g., an Xn-U Address Indication or a Data Address Indication message) to S-SN 106B. S-SN 106B may then send 352 an SN Status Transfer message to MN 104A, and MN 104A may then send 334 an SN Status Transfer message to C-SN 106A. In some implementations, for example, if S-SN 106B has not yet prepared the C-SN configuration for continuous CPAC, MN 104A may send 356 a UE Context Release message to S-SN 106B. Events 348, 350, 351, 352, 334, and 356 may be collectively referred to as an SN Release and SN Status Transfer process 396.

[0097] Figure 3C Depicts the Figure 3A and Figure 3B A similar scenario 300C, i.e., SN-initiated conditional SN change for continuous CPC is described below. Figure 3C and Figure 3A and Figure 3B The difference between.

[0098] At a certain point in time, S-SN 106B determines that a conditional SN change (preparation) procedure for continuous CPC should be initiated for one or more C-SNs. For example, S-SN 106B may make this determination based on measurement results from UE 102. In some implementations, UE 102 performs measurements on cells of one or more C-SNs according to the measurement configuration in the first SN configuration and sends the measurement results to S-SN 106B. In response to this determination, S-SN 106B sends 303 an SN Change Required message that includes the target SN ID of C-SN 106A, the CG-Config IE of C-SN 106A, and a reference C-SN configuration. In some implementations, S-SN 106B includes CPC information for C-SN 106A in the SN Change Required message. For example, the CPC information (e.g., the Conditional PSCell Change Information Required IE) includes an IE indicating the maximum number of PSCells that C-SN 106A can prepare. In such cases, S-SN 106B includes the CG-Config IE in the CPC information. The reference C-SN configuration in SN Change Required message 303 is similar to the reference C-SN configuration in event 342. In some implementations, S-SN 106B includes the reference C-SN configuration in the CG-Config IE. In other implementations, S-SN 106B includes the reference C-SN configuration in an X2AP / XnAP IE of the SN Change Required message, which is different from the X2AP / XnAP IE that carries the CG-Config IE. In some implementations, the SN Change Required message includes a second indication of continuous CPC for UE 102 (e.g., a Selective Activation Indication IE). In some implementations, S-SN 106B includes the trigger condition configuration for the condition to be detected for UE 102 in event 316 in the CG-Config IE.

[0099] After receiving the SN Change Required message, similar to event 304, MN 104A sends 305 a CSN Add Request message to C-SN 106A. In scenarios 300A and 300B, MN 104A derives the ID of C-SN 106A based on measurement results (received from UE 102) and association information pre-configured in MN 104A. For example, the association information indicates which cell is associated with which base station. In scenario 300C, MN 104A sends SN Add Request message 305 to C-SN 106A based on the target SN ID of C-SN 106A. In some implementations, MN 104A generates an inter-node RRC message (i.e., a CG-ConfigInfo IE) based on the CG-Config IE and includes the CG-ConfigInfo IE in the SN Add Request message. In some implementations, the CG-Config IE includes 1) a candidateCellInfoListSN IE, which includes measurement results for one or more cells of the C-SN 106A (e.g., cells 126A and / or 126C), and / or 2) a candidateCellListCPC IE, which indicates that the S-SN 106B proposes one or more cells (e.g., cells 126A and / or 126C) for the C-SN 106A to consider as a C-PSCell. The MN 104A includes the candidateCellInfoListSN IE and / or the candidateCellListCPC IE in the CG-ConfigInfo IE. In some implementations, the CG-Config IE includes a trigger condition configuration for connecting to the one or more cells (e.g., a CondReconfigExecCondSCG IE). Alternatively, the MN 104A includes the trigger condition configuration in a separate X2AP / XnAP IE in the SN Add Request message. In other implementations, the MN 104A avoids including the triggering condition in the SN Add Request message.

[0100] In some implementations, as described for event 304, the MN 104A includes the reference C-SN configuration in the SN Add Request message in event 305. In some implementations, the MN 104A includes the first indication (e.g., the Selective Activation Indication IE) for continuous CPAC in the SN Add Request message based on the second indication or in response to the second indication in event 305. In some implementations, if the MN 104A does not support the SN-initiated conditional SN change (preparation) procedure for continuous CPC and receives an SN change required message for continuous CPAC (e.g., the SN change required message in event 303) from the SN, the MN 104A may send an SN change reject message to the SN (e.g., S-SN 106B). In such a case, the MN 104A may support the SN-initiated conditional SN change (preparation) procedure for non-contiguous CPC (e.g., 3GPP Release 17 CPC).

[0101] In some implementations, S-SN 106B is permitted to initiate such a conditional SN change (preparation) procedure for continuous CPC with MN 104A because S-SN 106B previously received an SN add request message or an SN modify request message from MN 104A including an indication (e.g., a selective activation indication IE) before or during event 301. Based on the indication, S-SN 106B determines that MN 104A permits S-SN 106B to initiate an SN-initiated conditional SN change (preparation) procedure for continuous CPC with MN 104A. Therefore, S-SN 106B determines to send or sends an SN change required message in event 303. If S-SN 106B does not receive the indication, S-SN 106B refrains from initiating an SN-initiated conditional SN change (preparation) procedure for continuous CPC with MN 104A. In this case, S-SN 106B refrains from sending an SN change required message such as the message in event 303.

[0102] Similar to event 306, C-SN 106A sends 307 an SN Add Request Confirm message including M1 C-SN configurations to MN 104A in response to the SN Add Request message. MN 104A then sends the M1 C-SN configurations to UE 102 in process 310. In some implementations, based on the C-SN configurations, C-SN 106A generates each of the M1 C-SN configurations as an incremental configuration to enhance the reference C-SN configuration. Unlike scenarios 300A and 300B, in the RRC reconfiguration message of process 310, each of the conditional (re)configuration fields / IEs includes the triggering condition configuration received from S-SN 106B. After receiving the SN Add Request Confirm message or after or simultaneously with performing process 310 with UE 102, MN 104A sends 309 an SN Change Confirm message to S-SN 106B.

[0103] In some implementations, the target SN ID includes the IDs of C-SNs 2, ..., N, which are used for the SN-initiated conditional SN change (preparation) procedure for continuous CPC for C-SNs 2, ..., N. Therefore, as described above, the MN 104A may send an SN add request message to each of the C-SNs 2, ..., N.

[0104] Go to Figures 4A to 4B , scenarios 400A to 400B are generally similar to scenarios 300A to 300C. However, scenarios 400A to 400B involve intra-base station CPC, while scenarios 300A to 300C are related to CPA or inter-base station CPC.

[0105] Figure 4A Scenario 400A, ie, intra-SN continuous CPC, is depicted. Here, similar to event 301, UE 102 initially operates 402 with MN 104A and SN 106A in DC and communicates with SN 106A via PSCell 126B according to a first SN configuration.

[0106] Later, SN 106A determines to configure C-PSCells 1, ..., M1 for UE 102 to achieve inter-SN continuous CPC, where M1 is a positive integer. For example, SN 106A may make this determination based on measurement results from UE 102. In some implementations, UE 102 performs measurements on cells of SN 106A according to the measurement configuration in the first SN configuration and sends the measurement results to SN 106A. In response to this determination, similar to event 308, SN 106A generates a first SN RRC reconfiguration message including M1 C-SN configurations (i.e., C-SN configurations 1, ..., M1) and / or a reference C-SN configuration, and sends 406 the first SN RRC reconfiguration message to MN 104A. C-SN configurations 1, ..., M1 configure or are associated with C-PSCells 1, ..., M1, respectively. In some implementations, each of the M1 C-SN configurations is an incremental configuration that enhances the reference C-SN configuration. In some implementations, the reference C-SN configuration is a first SN configuration. In other implementations, the reference C-SN configuration is different from the first SN configuration. In still other implementations, the reference C-SN configuration is a subset of the first SN configuration. In some implementations, the reference C-SN configuration is a full configuration. In other implementations, the reference C-SN configuration is an incremental configuration that enhances the first SN configuration. In some implementations, the SN 106A sends an SN message (e.g., an SN modification request message) including a first SN RRC reconfiguration message to the MN 104A at event 406. Subsequently, the MN 104A sends 408 the first SN RRC reconfiguration message to the UE 102. UE 102, in response to the SN RRC reconfiguration message, UE 102 sends 412 a first SN RRC reconfiguration complete message to MN 104A, which in turn sends 413 a first SN RRC reconfiguration complete message to SN 106A. In some implementations, MN 104A may include the first SN RRC reconfiguration complete message in event 413 in the SN reconfiguration complete message.

[0107] In some implementations, the MN 104A generates an MN RRC message (e.g., an RRC reconfiguration message) including the first SN RRC reconfiguration message and sends the MN RRC message to the UE 102 at event 408. In such a case, the UE 102 sends an MN RRC response message (e.g., an RRC reconfiguration complete message) including the first SN RRC reconfiguration complete message to the MN 104A at event 412 in response to the MN RRC message.

[0108] UE 102 may later detect 416 that a condition for connecting to a first C-PSCell (e.g., C-PSCell 1) is met. In response to the detection, UE 102 performs 418 a random access procedure with SN 106A via the first C-PSCell and sends 420 a second SN RRC reconfiguration complete message to MN 104A, which in turn sends 422 the second SN RRC reconfiguration complete message to SN 106A. In some implementations, the second SN RRC reconfiguration complete message includes a configuration ID that indicates C-SN configuration 1 of the first C-PSCell to MN 104A. In some implementations, UE 102 includes the second SN RRC reconfiguration complete message in a ULInformationTransferMRDC message. In some implementations, MN 104A sends an SN message (e.g., an RRC transfer message) including the second SN RRC reconfiguration complete message to SN 106A at event 422.

[0109] After successfully completing the random access procedure, UE 102 communicates 436 with MN 104A and SN 106A in DC and communicates with SN 106A via the first C-PSCell according to the C-SN configuration. Events 418, 420, 422, and 436 may be collectively referred to as an (intra-SN) CPC execution procedure 494. Similar to event 418, UE 102 may later detect 438 that a condition for connecting to a second C-PSCell is met. Similar to event 494, UE 102, MN 104A, and SN 106A perform 495 an (intra-SN) CPC execution procedure for the second C-PSCell.

[0110] Next reference Figure 4B Scenario 400B is similar to scenario 400A, except that SN 106A sends 409 a first SN RRC reconfiguration message directly to UE 102 (e.g., via SRB3), and in response, UE 102 sends 411 a first RRC reconfiguration complete message directly to SN 106A (e.g., via SRB3). In response to detection 416, UE 102 performs 418 a random access procedure with SN 106A via the first C-PSCell and sends 421 a second SN RRC reconfiguration complete message directly to SN 106A (e.g., via SRB3).

[0111] Events 418, 421, 422, and 436 may be collectively referred to as an (intra-SN) CPC execution procedure 496. Similar to event 418, UE 102 may later detect 438 that a condition for connecting to a second C-PSCell is met. Similar to event 496, UE 102, MN 104A, and SN 106A perform 497 an (intra-SN) CPC execution procedure for the second C-PSCell.

[0112] In some implementations, SN 106A determines that a reference C-SN configuration (i.e., a first reference C-SN configuration) is to be updated. In response to this determination, similar to event 408 or 409, SN 106A sends a second reference C-SN configuration. If the second reference C-SN configuration is a full configuration, UE 102 replaces the first reference C-SN configuration with the second reference C-SN configuration. If, similar to event 416 or 438, the conditions for connecting to a C-PSCell are met, similar to events 418 and 436, 494, 495, 496, or 497, UE 102 performs a random access procedure on the C-PSCell and applies the C-SN configuration (configured C-PSCell or associated with a C-PSCell) and the second C-SN configuration to communicate with SN 106A.

[0113] In the case where the second reference C-SN configuration is an incremental configuration, UE 102 utilizes the second reference C-SN configuration to enhance the first reference C-SN configuration to obtain an updated reference C-SN configuration. Similar to event 416 or 438, if the conditions for connecting to the C-PSCell are met, similar to event 418 and events 436, 494, 495, 496, or 497, respectively, UE 102 performs a random access procedure on the C-PSCell and applies the C-SN configuration (configured C-PSCell or associated with C-PSCell) and the updated C-SN configuration to communicate with SN 106A.

[0114] As described above, after UE 102 applies the C-SN configuration, the applied C-SN configuration becomes the SN configuration (i.e., the serving or source SN configuration) or part of the SN configuration. After applying the C-SN configuration (e.g., in response to applying the C-SN configuration), UE 102 avoids deleting the conditional (re)configuration field / IE associated with the reference C-SN configuration.

[0115] In some implementations, similar to events 406 and 408 or event 409, SN 106A may generate a C-SN configuration that configures a specific C-PSCell for non-contiguous CPAC and send the C-SN configuration to UE 102. In such cases, the C-SN configuration for non-contiguous CPAC is not associated with the reference C-SN configuration. If, similar to event 416 or 438, the conditions for connecting to a specific C-PSCell are met, similar to event 318 and events 336, 394, or 395, respectively, UE 102 performs a random access procedure on the specific C-PSCell and applies the C-SN configuration to communicate with SN 106A on the specific C-PSCell. After applying the C-SN configuration, UE 102 deletes the conditional (re)configuration field / IE.

[0116] Figures 5A to 9 is a flow chart depicting example methods according to the techniques of this disclosure that a base station (e.g., base station 104A, 104B, 106A, or 106B) may implement to support a continuous CPAC process. As indicated throughout this disclosure, Figures 5A to 9 The example method depicted in FIG. 4 may be implemented during scenarios 300A to 300C and 400A to 400B described above.

[0117] Figure 5A A method 500A is shown for performing a conditional SN procedure with a C-SN (eg, C-SN 106A), which may be implemented by a MN (eg, MN 104A).

[0118] Method 500A begins at block 502, where the MN initiates a conditional SN procedure for the UE. At block 504, the MN 104A includes at least one of a selective activation indication, a reference C-SN configuration, and / or a conditional configuration in an SN request message. At block 506, the MN may include CPA information in the SN request message. At block 508, the MN sends an SN request message to the SN (e.g., event 304, 305, or 305C). At block 510, the MN receives an SN request acknowledgement message from the SN that includes the C-SN configuration (e.g., event 306 or 307). At block 512, the MN sends a message to the UE that includes the C-SN configuration (e.g., event 308 or 310). At block 514, the MN may receive a message from the UE that instructs the UE to apply the C-SN configuration (e.g., event 320, 394, or 395).

[0119] In some implementations, the CPA information includes a maximum number of PSCells to prepare IE and / or an estimated probability of arrival IE.

[0120] In some implementations, the CPA information is a conditional PSCell add information request IE. In some implementations, the selective activation indication is an IE other than the conditional PSCell add information request IE. In other implementations, the selective activation indication is included in the conditional PSCell add information request IE.

[0121] In some implementations, the reference C-SN configuration is an IE in addition to the conditional PSCell add information request IE. In other implementations, the reference C-SN configuration is included in the conditional PSCell add information request IE.

[0122] In some implementations, the conditional configuration configures one or more conditions for the UE to detect. The one or more conditions are similar to the conditions described for event 308.

[0123] In some implementations, the SN request confirm message includes an indication indicating a C-SN configuration for selective activation.

[0124] Figure 5B A method 500B is shown that is similar to 500A, except that method 500B additionally includes a decision block 503 that determines further process flow. At block 503, the MN determines whether the conditional SN procedure is for selective activation. If the MN determines that the conditional SN procedure is for selective activation, the process proceeds to block 504 and then as in 500A. Otherwise, if the MN determines that the conditional SN procedure is not for selective activation, the process proceeds to block 506 and then as in 500A.

[0125] Figure 5C Method 500C is shown, which is similar to 500B or 500A, except that method 500C provides an alternative flow process after decision block 503. At block 503, the MN determines whether the conditional SN procedure is for selective activation. If the MN determines that the conditional SN procedure is for selective activation, the flow proceeds to block 504. However, unlike 500A or 500B, the flow further proceeds directly to block 508 instead of block 506 (i.e., in the case where the conditional procedure is for selective activation, the MN does not include CPA information in the SN request message) and then proceeds as in 500A. Otherwise, if the MN determines that the conditional SN procedure is not for selective activation, the flow proceeds to block 506 as described in 500B.

[0126] Figure 6A A method 600A is shown for performing a conditional SN procedure with a C-SN (eg, C-SN 106A), which may be implemented by a MN (eg, MN 104A).

[0127] Method 600A begins at block 602, where the MN communicates with the UE, and the UE operates in a DC with the MN and the SN (e.g., event 302 or 402). At block 604, the MN receives a C-SN configuration from the C-SN (e.g., events 306, 307). At block 606, the MN sends the C-SN configuration to the UE (e.g., events 308, 310). At block 608, the MN receives a message from the UE or C-SN indicating that the UE is connected to the C-SN (e.g., event 320 or 324). At block 610, the MN sends an SN release request message to the SN (e.g., event 348). At block 612, the MN refrains from sending a UE context release message to the SN to release the UE context.

[0128] Figure 6B A method 600B is shown that is similar to 600A, except that method 600B includes block 611 instead of blocks 610 and 612. After block 608, flow proceeds to block 611 where the MN sends an SN Modify Request message to the SN to instruct the SN to cease communicating with the UE.

[0129] Figure 6C A method 600C is shown that is similar to 600A or 600B, except that method 600C includes a decision block 613 for further process flow. At block 610, flow proceeds to block 613, where the MN determines whether the C-SN configuration is for selective activation. If the MN determines that the C-SN configuration is for selective activation, flow proceeds to block 612. Otherwise, if the MN determines that the C-SN configuration is not for selective activation, flow proceeds to block 614, where the MN sends a UE context release message to the SN to release the UE context of the UE (e.g., event 356).

[0130] Figure 6D A method 600D is shown that is similar to 600C, 600B, or 600A, except that method 600D provides an alternative flow process after decision block 613. At block 613, the MN determines whether the C-SN configuration is for selective activation. If the MN determines that the C-SN configuration is for selective activation, the flow proceeds further to block 611. Otherwise, if the MN determines that the C-SN configuration is not for selective activation, the flow proceeds further to block 610, where the MN sends an SN Release Request message to the SN (e.g., event 348). The flow proceeds further to block 614, where the MN sends a UE Context Release message to the SN to release the UE context of the UE (e.g., event 356).

[0131] Figure 7A method 700 is shown for performing a conditional SN procedure with a MN (eg, MN 104A), which may be implemented by a C-SN (eg, C-SN 106A).

[0132] Method 700 begins at block 702, where the C-SN receives an SN request message from the MN, the SN request message including a selective activation indication, a reference C-SN configuration, a conditional configuration, and / or CPA information for the UE (e.g., event 304, 305, or 305C). At block 704, the C-SN sends an SN request confirmation message to the MN including at least one C-SN configuration (e.g., event 306 or 307). At block 706, the C-SN may communicate with the UE using a first of the reference C-SN configuration and the at least one C-SN configuration. At block 708, the C-SN may receive an SN message from the MN to release resources configured for the UE (e.g., event 348). At block 710, the C-SN may maintain the at least one C-SN configuration in response to receiving the SN message.

[0133] In some implementations, the C-SN includes an indication of the C-SN configuration for selective activation in an SN request confirm message. In some implementations, the SN message is an SN release request message. In other implementations, the SN message is an SN modify request message.

[0134] In some implementations, the C-SN determines (e.g., selects or identifies) a first C-SN configuration from at least one C-SN configuration. For example, the C-SN receives an RRC message (e.g., an RRC reconfiguration complete message) from the UE directly or via the MN, the RRC message including a configuration ID identifying the first C-SN configuration. The RRC message and / or the configuration ID instructs the UE to execute or apply the first C-SN configuration. In another example, the C-SN receives an SN message (e.g., an SN reconfiguration complete message or an SN modification request message), the SN message including a configuration ID identifying the first C-SN configuration. The SN message and / or the configuration ID instructs the UE to execute or apply the first C-SN configuration. Regardless of which of the above examples, the C-SN determines the first C-SN configuration based on or according to the configuration ID, the RRC message, or the SN message. In some implementations, when the UE detects conditions for connecting to a C-PSCell, the UE performs a random access procedure with the C-SN on the C-PSCell configured in the first C-SN configuration. In such a case, when the C-SN recognizes that the UE performs a random access procedure on the C-PSCell, the C-SN determines the first C-SN configuration.

[0135] Figure 8AA method 800A is shown for performing a conditional SN procedure with a MN (eg, MN 104A), which may be implemented by a C-SN (eg, C-SN 106A).

[0136] Method 800A begins at block 802, where the C-SN receives an SN request message including CPA information from the MN (e.g., event 304, 305, or 305C). At block 804, the C-SN includes the C-SN configuration in an SN request confirmation message. At block 806, the C-SN determines whether the SN request message includes a selective activation indication. If the C-SN determines that the SN request message includes a selective activation indication, the process proceeds to block 808, where the C-SN includes the selective activation indication and / or a reference C-SN configuration in the SN request confirmation message. The process further proceeds to block 810, where the C-SN sends an SN request confirmation message to the MN (e.g., event 306 or 307). Otherwise, if the C-SN determines that the SN request message does not include a selective activation indication, the process proceeds to block 810 (e.g., event 306 or 307).

[0137] Figure 8B A method 800B is shown that is similar to 800A, except that method 800B has a different decision block 807 instead of block 806 to facilitate further process flow. At block 807, the C-SN determines whether the SN request message includes a reference C-SN configuration. If the C-SN determines that the SN request message includes a reference C-SN configuration, the process proceeds to block 809, where the C-SN includes a selective activation indication and / or a reference C-SN configuration in an SN request confirmation message. The process further proceeds to block 810, where the C-SN sends an SN request confirmation message to the MN (e.g., event 306 or 307). Otherwise, if the C-SN determines that the SN request message does not include a reference C-SN configuration, the process proceeds to block 810.

[0138] In some implementations, the CPA indication is a conditional PSCell add information request IE.

[0139] Figure 9 A method 900 is shown for performing a conditional SN procedure with a MN (eg, MN 104A), which may be implemented by a SN (eg, S-SN 106B).

[0140] Method 900 begins at block 902, where the SN initiates a conditional SN procedure. At block 904, the SN includes at least one of a selective activation indication, a reference C-SN configuration, and / or a conditional configuration in an SN request message. At block 906, the SN may include CPC information in the SN request message. At block 908, the SN sends an SN request message to the MN (e.g., event 303). At block 910, the SN receives an SN confirmation message from the MN (e.g., event 309).

[0141] In some implementations, the CPC information is a Conditional PSCell Change Information Required IE. In some implementations, the Selective Activation Indication is an IE other than the Conditional PSCell Change Information Required IE. In other implementations, the Selective Activation Indication is included in the Conditional PSCell Change Information Required IE.

[0142] In some implementations, the reference C-SN configuration is an IE in addition to the Conditional PSCell Change Information Required IE. In other implementations, the reference C-SN configuration is included in the Conditional PSCell Change Information Required IE.

[0143] The following description can be applied to the above description.

[0144] In general, the description of one of the above figures may apply to another of the above figures. The examples, implementations, and methods described above may be combined unless there is a conflict. Events or blocks described above may be optional or omitted. For example, events or blocks with dashed lines in the figures may be optional. In some implementations, the term "message" may be used and "information element (IE)" may be substituted for "message." In some implementations, the term "IE" may be used and "field" may be substituted for "IE." In some implementations, the term "configuration" may be substituted for "multiple configurations" or configuration parameters. In some implementations, the terms "CPAC," "CPA," and / or "CPC" may be interchangeable. In some implementations, the term "reference C-SN configuration" may be substituted for "reference C-SN configuration" or "reference configuration." In some implementations, the terms "trigger condition" and "trigger condition configuration" may be substituted for "execution condition" and "execution condition configuration," respectively.

[0145] The user device (e.g., UE 102) in which the technology of the present disclosure may be implemented may 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 another personal media device, wearable device such as a smart watch, wireless hotspot, femtocell or broadband router. Further, in some cases, the user device may be embedded in an electronic system such as a head unit or an advanced driver assistance system (ADAS) of a vehicle. Further, the user device may operate as an Internet of Things (IoT) device or a mobile internet device (MID). Depending on the type, the user device may include one or more general-purpose processors, a computer-readable memory, a user interface, one or more network interfaces, one or more sensors, etc.

[0146] Certain embodiments are described in this disclosure as including 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 that is capable of performing certain operations and can be configured or arranged in a particular manner. A hardware module can include dedicated circuitry or logic that is permanently configured to perform certain operations (e.g., as a dedicated processor, such as a field programmable gate array (FPGA) or application-specific integrated circuit (ASIC), a digital signal processor (DSP), etc.). A hardware module can also include programmable logic or circuitry that is temporarily configured by software to perform certain operations (e.g., as contained within a general-purpose processor or other programmable processor). The decision to implement a hardware module using dedicated and permanently configured circuitry or using temporarily configured circuitry (e.g., circuitry configured by software) can be driven by cost and time considerations.

[0147] As used herein, the term "or" should be interpreted as inclusive, or to mean any one or any combination, unless expressly stated otherwise, mutually exclusive, or the context indicates otherwise. Thus, herein, the expression "A or B" means "A, B, or both A and B."

[0148] When implemented in software, the techniques may be provided as part of the operating system, as a library used by multiple applications, as a specific software application, etc. The software may be executed by one or more general-purpose processors or one or more special-purpose processors.

Claims

1. A method implemented in a first node of a radio access network RAN, the method comprising: Sending a request to a second node to operate as a secondary node (SN) and provide dual connectivity (DC) to a user equipment (UE), wherein the first node operates as a master node (MN), and the request includes an indication of adding or changing a continuous conditional secondary cell (CPAC); receiving a first conditional SN C-SN configuration from the second node in response to the request; as well as The first conditional SN configuration and a second conditional SN configuration related to at least one cell not associated with the second node are sent to the UE.

2. The method of claim 1, wherein: The request includes a reference C-SN configuration.

3. The method of claim 2, further comprising: The reference C-SN configuration is received from a third node of the RAN.

4. The method of claim 3, wherein the third node operates as one of: (i) Second C-SN, or (ii) providing the current SN of the DC to the UE before the UE sends the request to the second node.

5. A method as claimed in any one of the preceding claims, wherein: The request includes an indication of a maximum number of candidate cells to be prepared.

6. The method of any one of claims 1 to 3 or 5, further comprising, before said sending of said request: The current SN communicates with the UE using the DC; and An SN change request message is received from the current SN.

7. A method as claimed in any one of the preceding claims, wherein: The request is an SN add request message.

8. The method according to any one of the preceding claims, wherein the request is a first request, and the second node is a first candidate SN; The method further comprises: Sending a second request to another candidate SN; as well as In response to the second request, the second conditional SN configuration is received.

9. The method according to any one of the preceding claims, further comprising: An indication of a candidate cell to which the UE is connected is received from the UE, the candidate cell being referenced in the first conditional SN configuration or the second conditional SN configuration.

10. The method of claim 9, further comprising: At the first node, assigning a corresponding identifier to each conditional cell configuration included in the first conditional SN configuration and the second conditional SN configuration; wherein the indication of the candidate cell to which the UE is connected comprises a corresponding identifier assigned at the first node.

11. The method according to claim 9 or 10, wherein: The receiving of the indication comprises receiving an RRC reconfiguration complete message.

12. A method implemented in a first node of a Radio Access Network (RAN), the method comprising: sending, to a user equipment UE communicating in dual connectivity DC with the first node as a master node MN and the second node of the RAN as a secondary node SN, a conditional secondary node C-SN configuration related to a plurality of candidate cells for connection when one or more corresponding conditions are met, the plurality of candidate cells including a candidate cell of the candidate SN; receiving an indication that the UE is connected to the candidate cell; as well as A notification is sent to the SN based on whether the C-SN is used for continuous conditional cell changes, the continuous conditional cell changes being associated with the UE performing subsequent conditional cell changes based on the C-SN configuration.

13. The method of claim 12, wherein the sending comprises: In response to determining that the C-SN is for continuous conditional cell change, sending an SN modification request to the SN.

14. The method of claim 12, wherein the sending comprises: In response to determining that the C-SN is for a continuous conditional cell change, an indication is sent that the SN will stop communicating with the UE.

15. The method of claim 12, wherein the sending comprises: In response to determining that the C-SN is for a non-contiguous conditional cell change, an SN release request is sent to the SN.

16. The method of claim 15, further comprising: In response to determining that the C-SN is for a discontinuous cell change, a UE context release message for the UE is sent to the SN.

17. The method of claim 15, further comprising: An interface message including an Xn-U address indication is sent to the second node.

18. The method according to any one of claims 12 to 17, further comprising, before sending the C-SN configuration to the UE: Send an indication of adding or changing CPAC of a continuous conditional secondary cell to the SN.

19. The method according to any one of claims 12 to 17, further comprising, before sending the C-SN configuration to the UE: Sending a request for the C-SN operation to the C-SN, where the request for the C-SN operation includes an indication of adding or changing a continuous conditional secondary cell (CPAC).

20. The method of claim 19, wherein: The request for the C-SN operation further includes a reference C-SN configuration.

21. The method of claim 20, further comprising: The reference C-SN configuration is received from the SN.

22. A node in a Radio Access Network, RAN, the node comprising a transceiver and configured to implement the method of any preceding claim.

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