Handling of multiple target secondary nodes in SN-initiated conditional secondary node changes

Abstract

A primary mode (MN) provides a dual connectivity (DC) connection to a user equipment (UE) with a source secondary node (S-SN). A method in an MN comprises: receiving a first message from an S-SN indicating that a UE requires a change in the SN, the message comprising a plurality of information elements (IEs) for a plurality of target SNs, the UE connecting to one of the plurality of target SNs after a respective condition is satisfied, each of the IEs comprising an identifier of a respective one of the plurality of target SNs; and transmitting, to the S-SN, a second message indicating that the change of the SN is validated.

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 / 335,216, filed on April 26, 2022, entitled “HANDLING OF MULTIPLE TARGET SECONDARY NODES IN AN SN-INITIATED CONDITIONAL SECONDARY NODE CHANGE”. The entire contents of said 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 configurations for multiple connectivity, such as a conditional secondary node addition or change procedure. 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 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 connectivity is called multi-radio dual connectivity (MR-DC). When the UE operates under MR-DC, one base station operates as a master node (MN) covering a primary cell (PCell), and another 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 a wireless connection from one base station to another. For example, the serving base station may determine to switch the UE to a target base station and initiate a switching process.

[0006] 3GPP specification TS 37.340 v16.6.0 describes procedures for UE to add or change SN in DC scenario. These procedures involve message transfer (e.g., RRC signaling and preparation) between radio access network (RAN) nodes. Such message transfer generally results in delays, which in turn increases the probability that the SN addition or SN change procedure will fail. These legacy procedures that do not involve conditions checked at the UE may be referred to as "on-the-fly" SN addition 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 a handover, until the UE determines that a condition is met. As used herein, the term "condition" may refer to a single detectable state or event (e.g., a particular signal quality metric exceeds 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 the 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 the configuration that enables the UE to communicate with the base station or PSCell after the conditions have been met.

[0009] In the instant PSCell addition or change process, the RAN (i.e., MN or SN) sends an RRC reconfiguration message including multiple configuration parameters to the UE, 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 by using 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 by using matching security keys and multiple configuration parameters.

[0010] In some cases, a candidate SN (C-SN) (hereinafter also referred to as a target SN (T-SN)) identifies multiple candidate PSCells and generates multiple candidate configurations. When the MN completes preparations for a conditional SN procedure (e.g., conditional SN addition or conditional SN cell change), the MN cannot determine which candidate secondary cell the UE will connect to in the future. In addition, since the UE is connected to the secondary cell only when one or more conditions are met, the MN cannot determine at all whether the UE will connect to any of the candidate cells. Summary of the invention

[0011] An example implementation of the technology disclosed herein is a method in a master mode (MN) of a dual connectivity (DC) connection provided to a user equipment (UE) with a source secondary node (S-SN). The method includes: receiving a first message from the S-SN indicating that the UE requires a change of SN, the message including a plurality of information elements (IEs) for a plurality of target SNs, the UE connecting to one of the plurality of target SNs after corresponding conditions are met, each of the IEs including an identifier of a corresponding one of the plurality of target SNs; and sending a second message to the S-SN indicating that the change of SN is confirmed.

[0012] Another example implementation of these techniques is a method in a source secondary node (S-SN) that provides a dual connectivity (DC) connection to a user equipment (UE) with a primary node (MN). The method includes: sending a first message to the MN indicating that the UE requires a change of SN, the message including a plurality of information elements (IEs) for a plurality of target SNs, the UE connecting to one of the plurality of target SNs after corresponding conditions are met, each of the IEs including an identifier of a corresponding one of the plurality of target SNs; and receiving a second message from the MN indicating that the change of SN is confirmed.

[0013] Yet another example implementation of the techniques is a node in a radio access network (RAN), the node comprising processing hardware and configured to implement one of the methods described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1A is a block diagram of an example system in which a base station and / or a user equipment (UE) may implement the disclosed techniques for managing conditional procedures associated with a master node (MN) or a secondary node (SN);

[0015] Figure 1B is a block diagram of another example system in which a radio access network (RAN) and a user device may implement the techniques of the present disclosure for managing conditional procedures associated with a MN or SN;

[0016] Figure 1C is a block diagram of an example base station, the base station including a Figure 1A or Figure 1B Central Unit (CU) and Distributed Unit (DU) operating in a system;

[0017] 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;

[0018] Figure 3A is a message passing diagram of an example scenario in which a MN receives and processes one or more SN configurations from a C-SN during a conditional SN addition procedure;

[0019] Figure 3B is a message passing diagram of an example scenario in which a MN receives and processes one or more SN configurations from a C-SN during a MN-initiated conditional SN change procedure;

[0020] Figure 3C is a message passing diagram of an example scenario in which a MN receives and processes one or more SN configurations from a C-SN during an SN-initiated conditional SN change procedure;

[0021] Figure 3D is a message passing diagram of an example scenario in which a MN initiates a modification of a prepared conditional configuration following a MN-initiated conditional SN add or change or SN-initiated conditional SN change procedure;

[0022] Figure 3E is a message passing diagram of an example scenario in which the S-SN initiates modification of a prepared conditional configuration following a MN-initiated conditional SN change or SN-initiated conditional SN change procedure;

[0023] Figure 3F is a message passing diagram of an example scenario in which the C-SN initiates modification of a prepared conditional configuration following a MN-initiated conditional SN add or change or SN-initiated conditional SN change procedure;

[0024] Figure 4A is a flow chart of an example method that may be implemented in a C-SN for initiating a conditional SN change procedure associated with one or more C-SNs using one or more CG-Config IEs;

[0025] Figure 4Bis a flow chart of an example method that may be implemented in a C-SN for initiating a conditional SN change procedure associated with one or more C-SNs using a container IE containing one or more CG-Config IEs;

[0026] Figure 4C is a flow chart of an example method that may be implemented in a C-SN for initiating a conditional SN change procedure associated with one or more C-SNs using a container IE containing a single CG-Config IE;

[0027] Figure 5A is a flow chart of an example method that may be implemented in a MN for performing a conditional SN change procedure initiated by an S-SN and associated with one or more C-SNs using one or more CG-Config IEs;

[0028] Figure 5B is a flow chart of an example method that may be implemented in a MN for performing a conditional SN change procedure initiated by an S-SN and associated with one or more C-SNs using a container IE containing one or more CG-Config IEs;

[0029] Figure 5C is a flow chart of an example method that may be implemented in a MN for performing a conditional SN change procedure initiated by an S-SN and associated with one or more C-SNs using a container IE containing a single CG-Config IE;

[0030] Figure 5D is a flow chart of an example method that may be implemented in a MN for performing a conditional SN change procedure initiated by an S-SN and associated with one or more C-SNs using a container IE containing a single CG-Config IE;

[0031] Fig. 6A is a flow chart of an example method that may be implemented in a MN for performing a conditional SN change procedure initiated by an S-SN and associated with one or more C-SNs and maintaining execution conditions for C-SN configuration modification;

[0032] Figure 6B is a flow chart of an example method for performing, for a UE, a conditional SN change procedure initiated by an S-SN and associated with one or more C-SNs, and reacquiring execution conditions for C-SN configuration modification;

[0033] Figure 7 is a flow chart of an example method that may be implemented in a MN for performing a conditional SN procedure with a UE and a SN; and

[0034] Figure 8is a flow chart of an example method that may be implemented in a SN for performing a conditional SN procedure for a UE and a MN; DETAILED DESCRIPTION

[0035] 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) (the description also uses the acronyms CPA and CPC to separately refer to the conditional PSCell addition procedure and the conditional PSCell change procedure, respectively). More specifically, the base station uses a single SN change procedure to prepare multiple C-SNs and exchange information related to the S-SN configuration between the S-SN and the MN during the preparation phase of the CPC initiated by the SN. For example, the S-SN may send a list of proposed candidate PSCells for the C-SN to the MN, wherein the list includes execution conditions for each proposed candidate PSCell. The MN and / or S-SN use certain formats discussed below to manage the list of candidate PSCells and corresponding C-SNs in a single SN change procedure to reduce the complexity of determining which candidate PSCells belong to a specific C-SN at the MN and performing subsequent conditional SN addition preparations with the C-SN.

[0036] 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.

[0037] Among other components, the EPC 111 may include a serving gateway (SGW) 112, a mobility management entity (MME) 114, and a packet data network gateway (PGW) 116. In general, the SGW 112 is 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 and an access and mobility management function (AMF) 164 and / or a session management function (SMF) 166. In general, the UPF 162 is configured to deliver user plane packets related to audio calls, video calls, Internet services, etc.; the AMF 164 is configured to manage authentication, registration, paging, and other related functions; and the SMF 166 is configured to manage PDU sessions.

[0038] 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 with base station 104A and base station 106A operating as a master node (MN) and a secondary node (SN), respectively, under DC. In order to directly exchange messages in the DC scenario and other scenarios discussed below, MN 104A and SN 106A can support X2 or Xn interfaces. In general, CN 110 can be connected to any suitable number of base stations supporting NR cells and / or EUTRA cells. Reference is made below to Figure 1B An example configuration in which EPC 110 connects to additional base stations is discussed.

[0039] 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 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, which 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.

[0040] 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 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, which is configured to manage conditional configuration for one or more conditional processes (such as CHO, CPAC, or CSAC) when the base station 106A operates as a SN.

[0041] Still refer to Figure 1A, the 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 one or more general-purpose processors, and / or a dedicated processing unit. In an example implementation, the processing hardware 150 includes a UE conditional configuration controller 152, which is configured to manage conditional configuration for one or more conditional processes.

[0042] More specifically, conditionally configurable controllers 132, 142, and 152 may implement at least some of the techniques discussed with reference to the messaging and flow charts below. Figure 1A Conditionally configured controllers 132 and 142 are shown as separate components, but in at least some of the 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 conditionally configured controller 132 and conditionally configured controller 142 to support MN and SN functionality, respectively.

[0043] In operation, the UE 102 may use radio bearers (e.g., DRBs or SRBs) that terminate at different times at the MN 104A or the SN 106A. The UE 102 may apply one or more security keys when communicating on the radio bearers in the uplink (from the UE 102 to the BS) and / or downlink (from the base station to the UE 102) directions. In some cases, the UE may communicate with the base stations 104A and 106A using different RATs. Although the following examples may specifically relate to a specific RAT type (5GNR or EUTRA), in general, the techniques of the present disclosure may also be applicable to other suitable radio access and / or core network technologies.

[0044] Figure 1B Additional base stations 104B and 106B are depicted that may be included in the wireless communication system 100. The UE 102 initially connects to the base station 104A. The BSs 104B and 106B may have similar processing hardware as the base station 106A. The UE 102 initially connects to the base station 104A.

[0045] In some scenarios, base station 104A may perform an instant 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 MN and SN of UE 102, respectively. In some cases, UE 102 may operate using MR-DC connectivity 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 can help two base stations coordinate shared UE capabilities, including operating frequencies (e.g., band combinations, frequency ranges), UE measurements and reports (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).

[0046] At a certain point in time, when UE 102 is communicating with MN 104A and S-SN 106A under 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 multiple connectivity coordination may help newly added base stations coordinate shared UE capabilities.

[0047] In other scenarios, the base station 104A may perform a conditional SN addition procedure to first configure the base station 106B as the C-SN of the UE 102, i.e., conditional SN addition or change (CSAC). At this time, the UE 102 may be in single connectivity (SC) with the base station 104A, or in DC with the base station 104A and the base station 106A. If the UE 102 is in DC with the base station 104A and the base station 106A, the MN 104A may determine to perform the conditional SN addition procedure in response to a request received from the base station 106A or in response to one or more measurement results received from the UE 102 (e.g., extracted from a UE measurement report) or obtained by the MN 104A based on measurements of signals received from the UE 102 (e.g., a sounding reference signal (SRS) or an uplink demodulation reference signal (DMRS)). In contrast to the immediate SN addition scenario discussed above, the UE 102 does not immediately attempt to connect to the 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.

[0048] 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 discussion below only relates to a single condition). Multiple connectivity coordination is not necessary before the condition is met; however, it will be helpful once the C-SN becomes connected. When UE 102 determines that the condition has been met, UE 102 connects to C-SN 106B so that C-SN 106B begins to operate 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.

[0049] In yet other scenarios, UE 102 communicates with MN 104A (via PCell) and SN 106A (via a cell other than cell 126A). Figure 1A104A is in DC. SN 106A may perform conditional PSCell addition or change (CPAC) to configure a candidate PSCell (C-PSCell) 126A of 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 SRB, for example, in response to one or more measurement results, which may be received from UE 102 via 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 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 does not immediately disconnect from the PSCell and attempt to connect to the C-PSCell 126A.

[0050] More specifically, when UE 102 receives the configuration for C-PSCell 126A, UE 102 does not connect to C-PSCell 126A until UE 102 has determined that a certain condition is met (in some cases, UE 102 may consider multiple conditions, but for convenience, the discussion below only involves a single condition). When UE 102 determines that the condition has been met, UE 102 connects to C-PSCell 126A so that C-PSCell 126A begins to operate as C-PSCell 126A for UE 102. Therefore, although cell 126A operates as a C-PSCell instead of a PSCell, SN 106A may not yet be connected to UE 102 via cell 126A. In some implementations, UE 102 may disconnect from the PSCell to connect to C-PSCell 126A.

[0051] 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 good enough (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 the UE 102 successfully completes the random access procedure on the C-PSCell 126A, the C-PSCell 126A becomes the PSCell 126A of the UE 102. The SN 106A may then begin communicating data (user plane data or control plane data) with the UE 102 via the PSCell 126A. In another example, the UE 102 determines that the condition is met when one or more measurement results obtained by the UE 102 on the C-PSCell 126B are higher than a threshold configured by the MN 104A or the C-SN 106B or higher than a predetermined or preconfigured threshold. When the UE 102 determines that the signal strength / quality on the C-PSCell 126B of the C-SN 106B is good enough (again, measured relative to one or more quantitative thresholds or other quantitative metrics), the UE 102 may perform a random access procedure on the C-PSCell 126B with the C-SN 106B to connect to the 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 may then begin communicating data (user plane data or control plane data) with UE 102 over PSCell 126B.

[0052] In various configurations of the wireless communication system 100, the base station 104A may be implemented as a master eNB (MeNB) or a master gNB (MgNB), and the base station 106A or 106B may be implemented as a secondary gNB (SgNB) or a candidate SgNB (C-SgNB). The UE 102 may communicate with the base station 104A and the base station 106A or 106B (106A / B) via the same RAT (such as EUTRA or NR) or different RATs. When the base station 104A is a MeNB and the base station 106A is an SgNB, the UE 102 may be in EUTRA-NR DC (EN-DC) with the MeNB and the SgNB. In this scenario, the MeNB 104A may or may not configure the base station 106B as a C-SgNB for the UE 102. In this scenario, the SgNB 106A may configure the cell 126A as a C-PSCell for the UE 102. When base station 104A is a MeNB and base station 106A is a C-SgNB for UE 102, UE 102 may be in SC with the MeNB. In this scenario, MeNB 104A may or may not configure base station 106B as another C-SgNB for UE 102.

[0053] In some cases, the MeNB, SeNB, or C-SgNB is implemented as an ng-eNB instead of an eNB. When the base station 104A is a master ng-eNB (Mng-eNB) and the base station 106A is an SgNB, the UE 102 may be in the next generation (NG) EUTRA-NR DC (NGEN-DC) with the Mng-eNB and the SgNB. In this scenario, the MeNB 104A may or may not configure the base station 106B as the C-SgNB of the UE 102. In this scenario, the SgNB 106A may configure the cell 126A as the C-PSCell of the UE 102. When the base station 104A is a Mng-NB and the base station 106A is the C-SgNB of the UE 102, the UE 102 may be in the SC with the Mng-NB. In this scenario, the Mng-eNB 104A may or may not configure the base station 106B as another C-SgNB of the UE 102.

[0054] When base station 104A is a MgNB and base station 106A / B is an SgNB, UE 102 may be in NR-NR DC (NR-DC) with the MgNB and the SgNB. In this scenario, MeNB 104A may or may not configure base station 106B as a C-SgNB for UE 102. In this scenario, SgNB 106A may 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 may be in SC with the MgNB. In this scenario, MgNB 104A may or may not configure base station 106B as another C-SgNB for UE 102.

[0055] 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 may or may not 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 may or may not configure base station 106B as another C-Sng-eNB for UE 102.

[0056] 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 communicating with the EPC 111, an ng-eNB supporting an NG interface for communicating with the 5GC 160, or a base station supporting an NR radio interface and an NG interface for communicating 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.

[0057] 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 may communicate with base station 104A (operating as MN) and base station 106A (operating as SN) under DC, and after completing the SN change, communicate with base station 104A (operating as MN) and SN 104B. More specifically, when UE 102 operates with base station 104A and base station 106A under DC, base station 104A operates as MeNB, Mng-eNB, or MgNB, and base station 106A operates as 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 MeNB, Mng-eNB or MgNB, and base station 106B operates as C-SgNB or C-Sng-eNB. When UE 102 operates with base station 104A and base station 106A in DC, base station 104A operates as MeNB, Mng-eNB or MgNB, base station 106A operates as SgNB or Sng-eNB, and base station 106B operates as C-SgNB or C-Sng-eNB.

[0058] 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 examples below 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 applicable to other suitable radio access and / or core network technologies, such as sixth generation (6G) radio access and / or 6G core network or 5GNR-6G DC.

[0059] 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 that can be executed on 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 processes when base station 106A operates as a SN or a candidate SN (C-SN). Base station 106B may have the same or similar hardware as base station 106A. 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 executable on 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, the MAC controller is configured to manage or control one or more MAC operations or processes (e.g., random access processes); and a radio link control (RLC) controller, the RLC controller is configured to manage or control one or more RLC operations or processes when the base station 106A operates as a MN, SN, or candidate SN (C-SN). The processing hardware may also include a physical layer controller, the physical layer controller is configured to manage or control one or more physical layer operations or processes.

[0060] Figure 2 An example protocol stack 200 is shown in a simplified manner, according to which the UE 102 can communicate with an eNB / ng-eNB or gNB (e.g., one or more of the base stations 104, 106).

[0061] In the example stack 200, the physical layer (PHY) 202A of EUTRA 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 transfer services to the NR PDCP sublayer 210. The NR PDCP sublayer 210 may in turn provide data transfer services to the Service Data Adaptation Protocol (SDAP) 212 or the Radio Resource Control (RRC) sublayer ( Figure 2 In some implementations, 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 to support DC on EUTRA and NR interfaces. Figure 2 As shown, the UE 102 can support NR PDCP 210 layered on EUTRA RLC 206A, and SDAP sublayer 212 layered on NR PDCP sublayer 210.

[0062] 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 difference between SDUs and PDUs is relevant.

[0063] On the control plane, the EUTRA PDCP sublayer 208 and the NR PDCP sublayer 210 may provide a signaling radio bearer (SRB) or an RRC sublayer ( Figure 2 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.

[0064] Next, refer to FIG. 3A to FIG. 3FLet's discuss several example scenarios where the UE and / or RAN performs the techniques of the present disclosure for supporting conditional procedures. In general, FIG. 3A to FIG. 3F Similar events in the are marked with the same reference numerals, with the differences discussed below where appropriate.

[0065] First reference Figure 3A , in scenario 300A, the MN receives and processes one or more SN configurations from the SN during a conditional SN addition procedure. In scenario 300A, the base station 104A operates as a MN and the base station 106A operates as a C-SN. Initially, the UE 102 operates 302 with the MN 104A in single connectivity (SC). While in SC, the UE 102 communicates UL PDUs and / or DL ​​PDUs with the MN 104A (e.g., via the PCell 124A) according to the MN configuration.

[0066] At a later time, MN 104A determines to configure base station 106A as a C-SN for conditional PSCell addition (CPA). For example, MN 104A may make this determination based on measurement results from UE 102. 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 the determination, MN 104A sends 304 an SN add request message including a conditional PSCell add information request IE to C-SN 106A. In some implementations, the conditional PSCell add information request IE also includes a CPAC indicator for indicating CPAC initiation and a maximum number of PSCells to be prepared (Maximum Number of PSCells To Prepare) IE / field. MN 104A may generate candidate cell information (e.g., CandidateCellInfoListMN) including measurement results of one or more cells and include the candidate cell information in the SN add request message. In addition, MN 104A may determine SN restriction information for limiting (the value of) the configuration parameters that C-SN 106A may configure for UE 102. MN 104A may include the SN restriction information in the SN add request message. The candidate cell information and / or the SN restriction information may be included in the inter-node RRC message CG-ConfigInfo. MN 104A may also include SN restriction information (e.g., the maximum number of PSCells to be prepared) outside of CG-ConfigInfo in the SN add request message. When determining the SN restriction information, MN 104A may determine MN restriction information for limiting (the value of) the configuration parameters that MN 104A may configure for UE 102.

[0067] In response to receiving 304 an SN add request message with a CPAC indication, the C-SN 106A determines 306 one or more C-PSCells (C-PSCells) and generates an inter-node RRC message CG-CandidateList to include one or more C-SN configurations (C-SN configurations) for the UE 102, each C-SN configuration being associated with a specific C-PSCell in the C-PSCells. For example, the C-PSCells may be cell 126A and cell 126C. In some implementations, the C-SN 106A determines the C-PSCell and the C-SN configuration taking into account the candidate cell information and the SN restriction information. The CG-CandidateList includes an addition list of CG-CandidateInfo IEs (e.g., cg-CandidateToAddModList), each of which corresponds to a C-PSCell. Each CG-CandidateInfo IE in the added list includes C-PSCell information of the C-PSCell (e.g., SSB frequency information (e.g., ARFCN-ValueNR) and physical cell ID (PCI) or cell global ID (CGI)) and CG-Config IE. Each CG-Config IE includes a C-SN configuration for the corresponding C-PSCell and optional parameters for the MN to prepare conditional configuration. In some implementations, the CG-CandidateInfo IE includes a CG-CandidateInfo ID (e.g., cg-CandidateInfoId or CG-CandidateInfoId), which identifies each CG-CandidateInfo IE or the CG-Config IE in each CG-CandidateInfo IE by including the C-PSCell information of the C-PSCell (e.g., SSB frequency information (e.g., ARFCN-ValueNR) and physical cell ID (PCI) or cell global ID (CGI)) as an ID. The CG-CandidateInfo ID may be used by the C-SN 106A and the MN 104A to manage the CG-CandidateInfo IE in the added list.

[0068] The C-SN 106A sends 308 to the MN 104A an SN add request confirmation message including a CG-CandidateList and / or a conditional PSCell add information confirmation IE including a list of accepted candidate cells (CGI). In another implementation, the C-SN 106A may generate coordination information and include the coordination information in the SN add request confirmation message. In some implementations, the coordination information includes one or more coordination parameters. In some implementations, the C-SN 106A may include one or more coordination parameters in the CG-Config in the CG-CandidateList and / or the SN add request confirmation message. For example, the coordination information may include coordination parameters, such as one or more power coordination parameters (e.g., powerCoordination-FR1 and / or powerCoordination-FR2), or a discontinuous reception (DRX) configuration (e.g., DRX-Info or DRX-Info2). The coordination information may include coordination information for each of the C-PSCells. In some implementations, the C-SN 106A includes SN restriction information in the SN add request confirm message, which the MN 104A can use to determine the MN restriction information. Events 304, 306, 308 collectively define a conditional SN add prepare procedure 392.

[0069] After receiving 308 the SN add request confirmation 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, in the case where the CG-Config IE includes C-SN configurations 1, ..., N (N is an integer greater than zero), the MN 104A may assign configuration IDs 1, ..., N to the C-SN configurations 1, ..., N, respectively. In such a case, the MN 104A may include the configuration IDs 1, ..., N in the RRC reconfiguration message. In such an implementation, the MN 104A includes trigger condition configurations 1, ..., N for the C-SN configurations 1, ..., N, respectively, in the RRC reconfiguration. The MN 104A may generate a trigger condition configuration (e.g., condExecutionCond). 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. In some implementations, the MN 104A may generate conditional (re) configuration fields / IEs (e.g., CondReconfigToAddMod) 1, ..., N including C-SN configurations (e.g., condRRCReconfig) 1, ..., N, configuration IDs (e.g., condReconfigId) 1, ..., N, and trigger condition configurations (e.g., condExecutionCond) 1, ..., N, respectively, and send 312 an RRC reconfiguration message including the conditional (re) configuration fields / IEs to the UE 102. In other implementations, the MN 104A may generate RRC container messages (e.g., RRCConnectionReconfiguration message or RRCReconfiguration message) 1, ..., N respectively including C-SN configurations (e.g., condRRCReconfig) 1, ..., N, generate conditional (re)configuration fields / IEs (e.g., CondReconfigToAddMod) 1, ..., N respectively including RRC container messages 1, ..., N, configuration IDs (e.g., condReconfigId) 1, ..., N and conditional configurations (e.g., condExecutionCond) 1, ..., N, and send 312 an RRC reconfiguration message including the conditional configuration fields / IEs to the UE 102.

[0070] MN 104A may include the C-SN configuration in an RRC reconfiguration message (e.g., an RRCConnectionReconfiguration message or an RRCReconfiguration message) and send 312 the RRC reconfiguration message to UE 102. In response, UE 102 sends 314 an RRC reconfiguration complete message (e.g., an RRCConnectionReconfigurationComplete message or an RRCReconfigurationComplete message) to MN 104A. Events 312 and 314 together define the RRC reconfiguration procedure 310.

[0071] In some implementations, in response to receiving the RRC reconfiguration complete message, or after receiving the RRC reconfiguration complete message, the MN 104A sends an SN message (e.g., an SN Reconfiguration Complete message, not shown) to the C-SN 106A to indicate that the UE 102 has received the C-SN configuration. In other implementations, the MN 104A refrains from sending an SN message to the C-SN 106 to indicate that the UE 102 has received the C-SN configuration. Events 304, 306, 308, 312, and 314 collectively define a MN-initiated conditional SN change (addition) preparation procedure 390, which includes RRC reconfiguration steps not covered in procedure 392.

[0072] After receiving 314 an RRC reconfiguration complete message or an acknowledgement (e.g., an RLC acknowledgement or a hybrid automatic repeat request (HARQ) acknowledgement) to a PDU (e.g., an RLC PDU or a MAC PDU) including the RRC reconfiguration message, the MN 104A may (determine) send 316 an early state transfer message to the C-SN 106A to convey a COUNT value of the first downlink SDU forwarded by the MN 104A to the C-SN 106A or a COUNT value of the forwarded downlink SDUs for discarding each of the DRBs of the UE 102. The early state transfer message may be an early sequence number (SN) state transfer message, where "SN" in this context refers to a sequence number rather than a secondary node. In some implementations, the MN 104A may send 316 the early state transfer message without receiving an interface message indicating that the UE 102 is connected to the C-SN 106A.

[0073] UE 102 may use one or more conditions to determine whether to connect to one of the C-PSCells. If UE 102 detects 318 that the condition for connecting to the C-PSCell is met, UE 102 is connected to the C-PSCell. That is, the condition (or "trigger condition") triggers UE 102 to connect to the C-PSCell or perform C-SN configuration on the C-PSCell. However, if UE 102 does not detect that the condition is met, UE 102 is not connected to the C-PSCell. In response to the detection, UE 102 initiates a random access process on the C-PSCell. In response to the initiation, UE 102 performs 320 a random access process via the C-PSCell and C-SN 106A. In response to the detection or initiation 318, UE 102 sends 322 an RRC reconfiguration completion message to MN 104A. UE 102 may send 322 an RRC reconfiguration completion message before, during, or after the random access process.

[0074] In some implementations, the UE 102 may indicate in the RRC reconfiguration complete message that the UE 102 has performed the specific 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 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.

[0075] In response to receiving 322 the RRC reconfiguration complete message, or after receiving 322 the RRC reconfiguration complete message, the MN 104A may send 324 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 (e.g., an XnAP or X2AP message) defined in 3GPP 38.423 or 36.423 version 17 or future specifications. 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 322. In such a case, the MN 104A may include the SN RRC message in the SN message.

[0076] 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.

[0077] After the C-SN 106A successfully completes the random access procedure with the UE 102, the C-SN 106A may send 326 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, wherein the interface message may include PSCell information of the PSCell (e.g., cell 126A) and / or corresponding CG-Config IE and / or coordination information (e.g., SgNB resource coordination information IE or MR-DC resource coordination information IE) for physical resource block (PRB) coordination. The PSCell information may include a cell global identity (CGI), a physical cell identity (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 326 the interface message in response to receiving an SN message or performing 320 the random access procedure, or after receiving an SN message or performing 320 the random access procedure. 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.

[0078] In response to receiving 322 the RRC reconfiguration complete message or receiving 326 the interface message, or after receiving 322 the RRC reconfiguration complete message or receiving 326 the interface message, the MN 104A applies 328 the coordination information and / or the MN restriction information. In response to applying 328 the coordination information and / or the MN restriction information, the MN 104A may send 330 an RRC reconfiguration message including configuration parameters to the UE 102. In some implementations, the configuration parameters 330 may reconfigure or release (the values ​​of) configuration parameters used by the UE 102 to communicate with the MN 104A. In other implementations, the configuration parameters 330 may be new configuration parameters for configuring the UE 102 to communicate with the MN 104A. In response to the RRC reconfiguration message 330, the UE 102 may send 332 an RRC reconfiguration message to the MN 104A. In response, MN 104A may send 334 an SN modification confirmation message (e.g., an SgNB modification confirmation or an S-Node modification confirmation message). Events 320, 322, 324, 326, 328, 330, 332, and 334 may be sent in response to the SN modification confirmation message. Figure 3AIt is collectively referred to as the conditional SN addition execution process 394.

[0079] In response to or after receiving 322 the RRC reconfiguration complete message or receiving 326 the interface message, the MN 104A may send 336 an SN state transfer message to transfer the uplink PDCP SN and HFN receiver states and / or downlink PDCP SN and HFN transmitter states of each of the DRBs of the UE 102. In contrast to event 316, the MN 104A sends 336 a (non-early) SN state transfer message.

[0080] After the UE 102 successfully completes 320 the random access procedure, the UE 102 communicates 338 with the MN 104A and the C-SN 106A via the C-PSCell according to the C-SN configuration that configures the C-PSCell.

[0081] 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 uses the C-SN configuration to communicate with the SN 106A independently of the SN configuration. On the other hand, in other cases, the C-SN configuration includes an "incremental" configuration or one or more configurations that augment a previously received SN configuration. In these cases, the UE 102 uses the incremental C-SN configuration together with the SN configuration to communicate with the C-SN 106A.

[0082] 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) to 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.

[0083] In some implementations, the C-SN configuration includes configuring the C-PSCell 126A of the C-SN 106A and a group configuration (CellGroupConfig) IE of 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 RRCReconfigurat ion message, an RRCReconfiguration-IE or a CellGroupConfig IE in accordance with 3GPP TS38.331. The full configuration indication may be a field or IE in accordance with 3GPP TS 38.331. In other implementations, the C-SN configuration includes a SCG-ConfigPartSCG-r12 IE that configures the C-PSCell 126A of the C-SN 106A and zero, one, or more C-SCells. In some implementations, the C-SN configuration is an RRCConnectionReconfiguration message, an RRCConnectionReconfiguration-IE, or a ConfigPartSCG-r12 IE in accordance with 3GPP TS 36.331. The full configuration indication may be a field or IE in accordance with 3GPP TS 36.331.

[0084] Still refer to Figure 3A In some cases, the base station 106A (ie, C-SN) includes a CU 172 and one or more DUs 174, such as Figure 1C As shown. For each of the C-SN configurations, one or more DUs 174 may generate the C-SN configuration. Alternatively, for each of the C-SN configurations, one or more DUs 174 may generate a portion of the C-SN configuration, and the CU 172 may generate the remainder of the C-SN configuration. For example, the UE 102 performs 320 a random access procedure with the first DU 174A operating the (C-)PSCell 126A, and the first DU 174A may identify the UE 102 in the random access procedure. In this case, the UE 102 communicates 338 with the SN 106A via the first DU 174A.

[0085] The first DU 174A operating the C-SN 106A of the C-PSCell 126A may generate a C-SN configuration or a portion of the C-SN configuration configuring the C-PSCell 126A and send the C-SN configuration or the portion of the C-SN configuration to the CU 172. In the case where the DU generates a portion of the C-SN configuration, the CU 172 generates the remaining portion of the C-SN configuration. In some scenarios or implementations, the first DU 174A generates each of the other C-SN configurations. Alternatively, for each of the other C-SN configurations, the first DU 174A generates a portion of the C-SN configuration, and the CU 172 generates the remaining portion of the C-SN configuration. In other scenarios or implementations, the first DU 174A generates at least one first C-SN configuration in the C-SN configuration. Alternatively, for each of the at least one first C-SN configuration, the first DU 174A generates a portion of the C-SN configuration, and the CU 172 generates the remaining portion of the C-SN configuration. The second DU 174B of the C-SN 106A generates at least one second C-SN configuration in the C-SN configuration. Alternatively, for each of the at least one second C-SN configuration, the second DU 174B generates a portion of the C-SN configuration, and the CU 172 generates the remaining portion of the C-SN configuration.

[0086] Next reference Figure 3B In the MN-initiated conditional SN change scenario 300B, the MN 104A initially connects with the source SN (S-SN) 106B and later performs a conditional change procedure with the C-SN 106A. The interaction between the MN 104A and the C-SN 106A is similar to Figure 3A The following describes the interactions described in Figure 3B and Figure 3A The difference between.

[0087] UE 102 is initially in dual connectivity 301 with MN 104A and S-SN 106B, and communicates with S-SN 106B via PSCell according to S-SN configuration. At a later time, MN 104A, C-SN 106A, and UE 102 perform a conditional SN add preparation procedure 390. In the event that early data forwarding is required, MN 104A may send 340 an interface message (e.g., an Xn-U address indication or a data address indication message) to S-SN 106B. S-SN 106B then sends 342 an early state transfer message to MN 104A, and MN 104A then sends 316 an early state transfer message to C-SN 106A.

[0088] and Figure 3ASimilarly, UE 102 later detects 318 that the conditions for connecting to the C-PSCell are met, and in response to the detection, performs a random access procedure with C-SN 106A on the C-PSCell. UE 102, MN 104A, and C-SN 106A perform conditional SN addition execution 394. MN 104A sends 344 an SN release request message (e.g., an SgNB release request or an S-Node release request message) to S-SN 106B. In response, S-SN 106B sends 346 an SN release request confirmation message (e.g., an SgNB release request confirmation or an S-Node release request confirmation message). In the event that data forwarding is required, MN 104A may send 347 an 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 348 an SN state transfer message to MN 104A, and MN 104A may then send 336 an SN state transfer message to C-SN 106A. MN 104A sends 350 a UE context release message to S-SN 106B. Events 344, 346, 347, 348, 336, 350 may be collectively referred to as a SN release and SN state transfer process 396.

[0089] After the UE 102 successfully completes 320 the random access procedure, the UE 102 communicates 338 with the MN and with the SN via the C-PSCell 126A according to the C-SN configuration configuring the C-PSCell 126A.

[0090] Next reference Figure 3C In the SN-initiated conditional SN change scenario 300C, MN 104A initially connects with S-SN 106B, and later, S-SN 106B later triggers MN 104A to perform a conditional change procedure with C-SN 106A and / or an additional C-SN 104B not shown in the figure. The interaction between MN 104A and C-SN 106A (and / or C-SN 104B) is similar to Figure 3A or Figure 3B The following describes the interactions described in Figure 3C and Figure 3A and Figure 3B The difference between.

[0091] The S-SN 106B decides at a certain point in time to initiate a conditional SN change procedure for one or more C-SNs, and sends 303 an SN change required message (e.g., an SgNB change required or S-Node change required message defined in 3GPP TS 36.423 and 38.423, respectively) including one or more candidate target SN IDs (e.g., a global en-gNB ID or a global NG-RAN node ID) and one or more CG-Config IEs. The CG-Config IE includes: 1) candidate cell information (e.g., candidateCellInfoListSN defined in 3GPP TS 38.331), which also includes measurement results received from the UE for immediate PSCell change or CPC operation; 2) a candidate cell information list for CPC (e.g., candidateCellInfoListCPC defined in 3GPP TS 38.331), which also includes 1) candidate cells from which the C-SN is allowed to select and 2) triggering conditions for the corresponding candidate cells of MN 104A (e.g., condExecutionCondSCG or condExecutionCondSN IE defined in 3GPP TS38.331, which may include a measurement ID that references the configured S-SN measurement). The SN may also include corresponding SN limits for each C-SN (e.g., the maximum number of PSCells to be prepared). According to the received target SN ID, MN 104A and C-SN 106A (and / or C-SN 104B) perform conditional SN addition preparation process 392 with the proposed candidate cell information and SN restriction from S-SN 106B. In the CG-ConfigInfo IE included in the SN Add Request message, it includes 1) candidatesCellInfoListSN IE of the measurement result received from S-SN (instead of Figure 3A and Figure 3B 1) candidatesCellInfoListMN IE of the proposed candidate cell list specifically for C-SN 106A (and / or C-SN 104B) from S-SN 106B. 2) candidatesCellListCPC IE of the proposed candidate cell list specifically for C-SN 106A (and / or C-SN 104B) from S-SN 106B.

[0092] The following are example formats of several messages and information elements that the base station may use to correlate the target SN ID with the proposed candidate cell list from the S-SN when preparing the CG-ConfigInfo IE for the corresponding C-SN.

[0093] According to the following format of the Conditional PSCell Change Information Required IE in the SN Change Required message, the S-SN includes a corresponding RRC container that contains only the proposed candidate cells for the corresponding C-SN:

[0094]

[0095]

[0096] According to this format, the target SN ID and the RRC container are in the same multi-target SN node entry and thus form a pair. The MN can use the CandidateCellInfoListCPC-r17 in the corresponding CG-Config to prepare the CandidateCellListCPC-r17 in the CG-ConfigInfo for the corresponding C-SN and include the CG-ConfigInfo in the SN Add Request message.

[0097] Some of the relevant IEs are defined as follows:

[0098]

[0099] Therefore, the S-NODE modification request (direction is M-NG-RAN node → S-NG-RAN node) can have the following format:

[0100]

[0101]

[0102]

[0103] An SN change request may have the following format:

[0104]

[0105]

[0106] According to another example implementation, the S-SN includes the CG-CandidateList in the SN to MN container (e.g., S-NG-RAN node to M-NG-RAN node container or SgNB to MeNB container) in the SN change required message.

[0107]

[0108] According to this format, the sequence of candidateCG-Config-r17 appearing in CG-CandidateList is the same as the sequence of target SN ID appearing in the conditional PSCell change information requirement IE, so that the base station can pair this information. The MN can use the CandidateCellInfoListCPC-r17 in the corresponding CG-Config to prepare the CandidateCellListCPC-r17 in the CG-ConfigInfo for the corresponding C-SN, and include the CG-ConfigInfo in the SN Add Request message.

[0109] According to another example implementation, the S-SN includes the CG-Config with the full candidate cell list in the SN to MN container (e.g., S-NG-RAN node to M-NG-RAN node container or SgNB to MeNB container) in the SN change request message.

[0110]

[0111] Each of the CandidateCell-r17 elements has an additional target SN ID field / IE so that the cell and SNID can form a pair. The MN then divides the CandidateCellInfoListCPC-r17 according to the targetSNId to prepare the CandidateCellListCPC-r17 in the CG-ConfigInfo for the corresponding C-SN, and includes the CG-ConfigInfo in the SN Add Request message.

[0112] According to yet another example implementation, the S-SN includes the CG-CandidateList in a SN to MN container (e.g., S-NG-RAN node to M-NG-RAN node container or SgNB to MeNB container) in the SN change required message.

[0113]

[0114] Each of the CandidateInfo-r17 has an additional target SN ID field / IE so that candidatesCG-Config and targetSNId form a pair. The MN can use the CandidateCellInfoListCPC-r17 in the corresponding CG-Config to prepare the CandidateCellListCPC-r17 in the CG-ConfigInfo for the corresponding C-SN, and include the CG-ConfigInfo in the SN Add Request message.

[0115] According to another implementation, the S-SN includes the CG-Config with the full candidate cell list in the SN to MN container (e.g., S-NG-RAN node to M-NG-RAN node container or SgNB to MeNB container) in the SN Change Required message. In the Conditional PSCell Change Information Required IE in the SN Change Required message, the S-SN may include the corresponding candidate PSCell ID list of the proposed candidate cells with only the corresponding C-SN:

[0116]

[0117]

[0118] According to the PSCell ID PCI in the conditional PSCell change information requirement IE, the MN can pair the target SN with the candidate cell. The MN then divides the CandidateCellInfoListCPC-r17 according to the target SN ID to prepare the CandidateCellListCPC-r17 in the CG-ConfigInfo for the corresponding C-SN, and includes the CG-ConfigInfo in the SN Add Request message.

[0119] According to another example implementation, the S-SN includes a dedicated list (e.g., S-SN-CandidateList) in an SN to MN container (e.g., S-NG-RAN node to M-NG-RAN node container or SgNB to MeNB container) in the SN change required message.

[0120]

[0121] The sequence of candidateCG-Config-r17 in S-SN-CandidateList is the same as the sequence of target SN ID in conditional PSCell change information requirement IE, so that these forming units form a pair. The MN can use CandidateCellInfoListCPC-r17 in the corresponding CG-Config to prepare CandidateCellListCPC-r17 in CG-ConfigInfo for the corresponding C-SN, and include CG-ConfigInfo in the SN Add Request message.

[0122] Another example implementation is shown in the following table:

[0123]

[0124] The S-SN includes a CG-Config with a full candidate cell list with only cell PCI information in the SN to MN container (e.g., S-NG-RAN node to M-NG-RAN node container or SgNB to MeNB container) in the SN change request message. In this example implementation, the MN should first maintain a table of paired cell CGI and PCI (and / or ARFCN) of neighboring nodes (e.g., via an Xn or X2 setup procedure, an NG-RAN node configuration update procedure, an eNB configuration update procedure, or a CGI report from a UE). Based on the table and the received candidate cell ID (i.e., the CGI received in the conditional PSCell change information request IE or the PCI and ARFCN received in CandidateCellInfoListCPC), the MN looks up the table and pairs the target SN with the candidate cell. The MN then divides the CandidateCellInfoListCPC-r17 according to the target SN ID to prepare the CandidateCellListCPC-r17 in the CG-ConfigInfo for the corresponding C-SN, and includes the CG-ConfigInfo in the SN add request message.

[0125] MN 104A may send 352 an SN request message (e.g., an SgNB modification request or an S-Node modification request message) to S-SN 106B to provide candidate PSCells accepted by C-SN 106A (and / or C-SN 104B). In some implementations, the SN request message includes a conditional PSCell change information update IE, which also includes a cell CGI list of candidate cells accepted by the C-SN. In response, S-SN 106B may send 354 an SN request confirmation message (e.g., an SgNB modification request confirmation or an S-Node modification request confirmation message) to provide updated measurement configurations and / or triggering conditions. In some implementations, the SN request confirmation message may include a conditional PSCell change information update response IE, which also includes the updated measurement configurations and / or triggering conditions in one or more CG-Config IEs. One or more CG-Config IEs may each be included in a container in the conditional PSCell change information update response IE. In other implementations, the SN request confirmation message may not include a conditional PSCell change information update response IE, and the S-SN 106B includes a single CG-Config IE in the SN to MN container to include the updated measurement configuration and / or triggering conditions. The MN 104A performs 310 an RRC reconfiguration process with the UE 102 to configure the conditional configuration. The MN 104A sends 309 an SN change confirmation message (e.g., an SgNB change confirmation or an S-Node change confirmation message) to the S-SN 106B. If the MN does not send 352 an SN request message, the SN change confirmation message may include the candidate cells accepted by the C-SN. If the SN request confirmation message at event 354 includes an RRC reconfiguration message, the SN change confirmation message may include an RRC reconfiguration completion message for the S-SN 106B. Events 303, 392, 352, 354, 310, and 309 may be collectively referred to as a conditional SN change preparation process 393 initiated by the SN.

[0126] In some implementations, after event 393, S-SN 106B may also send an SN modification required message to UE 102 to trigger the CPC execution condition of CPC or the update of the corresponding SCG measurement configuration (if any). In this case, MN 104A reconfigures UE 102 as in event 310. MN 104A may send an SN modification confirmation message including an SN RRC reconfiguration complete message to S-SN 106B.

[0127] If UE 102 later detects 318 that the conditions for connecting to the C-PSCell are met, then similarly, UE 102 performs a random access procedure with C-SN 106A via the C-PSCell and performs a conditional SN addition execution procedure 394. MN 104A, S-SN 106B, and C-SN 106A may perform 396 SN release and SN state transfer procedures.

[0128] Go to Figures 3D to 3F , scenarios 300D to 300F are substantially similar to scenarios 300A to 300C. However, scenarios 300D to 300F involve modifications (eg, addition, replacement, or cancellation) to the prepared conditional SN addition or change configuration.

[0129] First reference Figure 3D In scenario 300D, UE 102 initially operates 302 with MN 104A in single connectivity (SC) or 301 with MN 104A and S-SN 106B in DC, and communicates with S-SN 106B via PSCell according to S-SN configuration. UE 102 later operates 302 with MN 104A in single connectivity (SC) or 301 with MN 104A and S-SN 106B in DC. Figure 3A Execute the CPA conditional SN addition preparation process 390, or follow Figure 3B May be performed as part of a MN-initiated conditional SN change preparation procedure, or in accordance with Figure 3C The CPC's SN initiated conditional SN change preparation procedure 393 is performed together with the MN 104A, (S-SN 106B) and C-SN 106A.

[0130] At a later time, MN 104A determines to change the SN limit (e.g., change the maximum number of PSCells to be prepared) or update one or more measurement results (e.g., update the candidate cell information to include additional, different, or fewer candidate cell measurement results compared to the previous preparation in event 390 or 393). For example, a first candidate cell not considered during process 390 or 393 may have a signal strength above a certain signal strength threshold, while a second candidate cell configured during event 390 or 393 may have a signal strength below another signal strength threshold. MN 104A sends 356 an SN request message (e.g., an SgNB modification request or an S-Node modification request message) including the updated SN limit and / or measurement results. In some implementations, the updated SN limit (e.g., the maximum number of PSCells to be prepared) is included in a conditional PSCell addition information modification request IE in the SN request message. The C-SN 106A performs 358 addition, replacement (i.e., modification), or cancellation (i.e., release) of a CG-Config IE or a CG-CandidateInfo IE associated with the C-PSCell of the UE 102 based on the updated information. More specifically, the C-SN 106A may generate an add list, a modify list, or a release list to respectively add, modify, or release one or more CG-Config IEs or CG-CandidateInfo IEs associated with the C-PSCell of the UE 102. In response to receiving 356 the SN request message, the C-SN 106A may send 360 an SN request confirmation message (e.g., an SgNB modification request confirmation message or an S-Node modification request confirmation message) including the add list, the modify list, and / or the release list to the MN 104A. In some implementations, the C-SN 106A may generate a CG-CandidateList including the add list, the modify list, and / or the release list, and include the CG-CandidateList in the SN request confirmation message. In other implementations, C-SN 106A includes the release list in the SN request confirmation message as an IE separate from the CG-CandidateList, for example. In some implementations, the SN request confirmation message includes a conditional PSCell add information modification confirmation IE, which also includes the full list of currently prepared PSCells.

[0131] The following paragraphs respectively describe example implementations of adding a list, modifying a list, and releasing a list, and how the MN 104A updates the CG-Config IE.

[0132] To add one or more CG-Config IEs or CG-CandidateInfo IEs associated with the C-PSCell of the UE 102, in one implementation, the C-SN 106A generates an add list, the add list including all previous CG-CandidateInfo IEs sent to the MN 104A in event 390 or 393 and the CG-CandidateInfo IEs to be added in addition, wherein each CG-CandidateInfo IE contains new C-PSCell information (e.g., SSB frequency information (e.g., ARFCN-ValueNR) and physical cell ID (PCI) or cell global ID (CGI)) of the new C-PSCell and the new CG-Config IE. After receiving 360 the add list, the MN 104A replaces the previous CG-CandidateList of event 390 or 393 with the add list. In an alternative implementation, C-SN 106A includes new CG-CandidateInfo IEs in the added list, where each CG-CandidateInfo IE contains new C-PSCell information and / or a new CG-Config IE and a new CG-CandidateInfo ID for a new C-PSCell. In such a case, C-SN 106A may or may not include all previous CG-CandidateInfo IEs sent to MN 104A in event 390 or 393 in the added list. Due to the new CG-CandidateInfo ID, MN 104A retains the previous CG-CandidateInfo IEs of event 390 or 393 and stores (i.e., adds) the new CG-CandidateInfo IEs.

[0133] In order to modify one or more of the previous CG-CandidateInfo IEs in the CG-CandidateList of event 390 or 393, each CG-CandidateInfo IE including C-PSCell information of the configured C-PSCell (e.g., SSB frequency information (e.g., ARFCN-ValueNR) and physical cell ID (PCI) or cell global ID (CGI)), in one implementation, C-SN 106A generates a modification list including new CG-CandidateInfo IEs, wherein each CG-CandidateInfo IE includes C-PSCell information of the configured C-PSCell and a new CG-Config IE. C-SN 106A may also include other previous CG-CandidateInfo IEs in the CG-CandidateList of event 390 or 393 that C-SN 106A determines not to modify in the modification list. After receiving 360 to the modification list, the MN 104A replaces all previous CG-Config IEs or CG-CandidateInfo IEs in the CG-CandidateList of the event 390 or 393 with the CG-Config IE or CG-CandidateInfo IE in the modification list. Alternatively, after receiving 360 to the modification list, the MN 104A replaces the CG-CandidateList of the event 390 or 393 with the modification list. In an alternative implementation, the C-SN 106A includes new CG-CandidateInfo IEs (where each CG-CandidateInfo IE contains C-PSCell information and / or CG-Config IE) and the existing CG-CandidateInfo ID in the CG-CandidateInfo IE of the event 390 or 393 in the modification list. Based on the CG-CandidateInfo ID, the MN 104A identifies and modifies (or replaces) the CG-Config IE and / or CG-CandidateInfo IE of the event 390 or 393. In such cases, C-SN 106A may or may not include the unmodified CG-CandidateInfo IE that C-SN 106A sent to MN 104A in event 390 or 393 in the modification list.

[0134] In some implementations, C-SN 106A may combine the addition list and the modification list in a single list (e.g., CG-CandidateToAddModList). In such a case, based on the cell ID and / or SSB frequency information and / or CG-CandidateInfo ID, MN 104A identifies and adds (or modifies) the (existing) CG-Config IE and / or CG-CandidateInfo IE associated with the cell ID and / or SSB frequency information and / or CG-CandidateInfo ID. For example, if the cell ID and / or SSB frequency information and / or CG-CandidateInfo ID does not exist after event 390 or 393, MN 104A adds the CG-Config IE and / or CG-CandidateInfo IE; otherwise, MN 104A modifies (or replaces) the existing CG-Config IE and / or CG-CandidateInfo IE.

[0135] In order to release one or more CG-Config IEs or CG-CandidateInfo IEs associated with the C-PSCell of the UE 102, in one implementation, the C-SN 106A generates a release list that includes all previous CG-Config IEs or CG-CandidateInfo IEs sent to the MN 104A in addition to those to be released. After receiving 360 the updated CG-CandidateList, the MN 104A replaces the previous CG-CandidateList of event 390 or 393 with the release list. In an alternative implementation, the C-SN 106A includes the cell ID information (e.g., PCI or CGI) of the C-PSCell and / or the SSB frequency information associated with the C-PSCell in the release list (e.g., cg-CandidateToReleaseList-r17) to indicate the CG-Config IE or CG-CandidateInfo IE to be released. According to the cell ID and / or SSB frequency information, the MN 104A identifies and releases the CG-Config IE and / or CG-CandidateInfo IE associated with the cell ID and / or SSB frequency information.

[0136] In some implementations, if the C-SN cancels or releases all previously prepared C-SN configurations, the 356SN request message may be an SgNB release request message or an S-Node release request message excluding the updated information, rather than an SN modification request message, and the 360SN request confirmation message may be an SgNB release request confirmation message or an S-Node release request confirmation message excluding the updated CG-CandidateList or release list.

[0137] After receiving 360 the SN request confirmation message, the MN 104A may perform 362 an update of the (stored) C-SN configuration according to the received information (e.g., the updated CG-CandidateList, including the add, modify, or release list or a separate release / modify list IE), as described above in the example implementation for the add, modify, or release list. In some implementations, to update the conditional configuration at the UE 102, the MN 104A (which does not recognize and associate the CG-Config and) treats the received information (e.g., the updated CG-CandidateList) as a new preparation for the conditional configuration, and performs the update according to the Figure 3A 308 in the RRC reconfiguration process. In some implementations, depending on the addition, modification, or release list, the MN 104A may associate the updated C-SN configuration with an existing conditional configuration ID (e.g., condReconfigId or CondReconfigurationId), or assign a new conditional configuration ID in the case of adding a new C-SN configuration. The updated C-SN configuration is included in the RRC reconfiguration message. In some implementations, for CPAC replacement or addition, the updated C-SN configuration is included in CondReconfigToAddModList, where each entry includes a configuration ID (e.g., condReconfigId or CondReconfigurationId), a trigger condition configuration (e.g., condExecutionCond), and a C-SN configuration (e.g., condRRCReconfig). For CPAC cancellation, the updated C-SN configuration is included in CondReconfigToRemoveList, where each entry includes a configuration ID (e.g., condReconfigId or CondReconfigurationId). MN 104A sends 364 an RRC reconfiguration message including the updated C-SN configuration to UE 102. UE 102 applies the reconfiguration and sends 366 an RRC reconfiguration complete message to MN 104A.

[0138] In the case of a SN initiated conditional SN change situation (ie, performing process 393), the MN 104A may send 368 a conditional PSCell change cancel message to the S-SN 106B to inform the S-SN 106B that the prepared PSCell list is cancelled in the C-SN 106A.

[0139] and Figure 3A or Figure 3B Similarly, if conditional configuration is still configured at UE 102 after event 364, UE 102 can later detect that the conditions for connecting to C-PSCell are met and perform a random access procedure with C-SN 106A via C-PSCell. Conditional SN addition execution procedure 394 and / or SN release and SN state transfer procedure 396 are also performed.

[0140] Next reference Figure 3E Scenario 300E is similar to scenario 300D; however, in scenario 300E, after the MN-initiated CPC conditional SN addition preparation process 390 or the SN-initiated conditional SN change preparation process 393, the S-SN 106B decides to initiate a modification of the (prepared conditional) configuration. Figure 3D and Figure 3E Another difference between .

[0141] In some implementations, the SN initiated conditional SN change preparation process 393 is performed, and later, the S-SN 106B, for example, updates one or more measurement results (e.g., updates the candidate cell information to include additional, different, or fewer candidate cells than the previous preparation in event 390 or 393) or changes the SN limit at the C-SN 106A (e.g., the maximum number of PSCells to be prepared). In other implementations, the MN initiated conditional SN change preparation 390 is performed, and later, the S-SN 106B, for example, decides to modify one or more configurations at the S-SN 106B. Therefore, the S-SN 106B sends 370 an SN required message (e.g., an SgNB modification required, an S-Node modification required, an SgNB change required, or an S-Node change required message) to the MN 104A, wherein the SN required message may include updated measurement results and / or updated SN restrictions (e.g., the maximum number of PSCells that may be prepared by each target SN) and / or updated trigger conditions corresponding to candidate cells and target SN IDs and / or updated S-SN configurations. For updates / modifications of the previous CPC configuration provided in CPC preparation, the S-SN 106B may or may not include the RRC container for the CG-Config in the SN change required message. (In the case where the S-SN configuration is to be updated, the MN 104A may perform an RRC reconfiguration procedure with the UE 102, Figure 3E MN 104A sends 356 an SN request message (e.g., an SgNB modification request message or an S-Node modification request message) including the updated measurement result and / or the updated SN restriction and / or the updated S-SN configuration to C-SN 106A. C-SN 106A performs 358 addition, replacement (i.e., modification) or cancellation (i.e., release) of the CG-Config IE or CG-CandidateInfo IE associated with the C-PSCell of UE 102 based on the updated information. C-SN 106A sends 360 an SN request confirmation message (e.g., an SgNB modification request confirmation message or an S-Node modification request confirmation message) including the updated CG-CandidateList to MN 104A, as shown in FIG. Figure 3D As described in Figure 3D After updating 362 the C-SN configuration as described and performing RRC reconfiguration procedures 364 and 366 to update the C-SN configuration at the UE 102, the MN 104A may send 374 an SN confirmation message (e.g., SgNB modification confirmation, S-Node modification confirmation, SgNB change confirmation, S-Node change confirmation message) to the S-SN 106B.

[0142] If UE 102 later successfully detects that the conditions for connecting to C-PSCell are met and performs conditional SN addition execution procedure 394, MN 104A performs SN release and SN state transfer procedure 396 with S-SN 106B and C-SN 106A. In the case where the SN initiated conditional SN change preparation procedure 393 is performed, MN 104A may not send 344 an SN release request message, and therefore, S-SN 106B may not send 346 an SN release request confirmation message in the SN release and SN state transfer procedure 396.

[0143] Next reference Figure 3F , scenario 300F is similar to scenario 300D or 300E; however, in scenario 300F, C-SN 106A may decide to modify one or more of the conditional configurations after performing the conditional SN addition preparation process 390 or the SN-initiated conditional SN change preparation process 393. In one example, C-SN 106A determines to cancel one or more of the conditional configurations in response to detecting congestion or resource shortage. In another example, C-SN 106A determines to modify one or more of the conditional configurations in response to detecting resource shortage. In yet another example, C-SN 106A determines to configure a new additional conditional configuration in response to detecting that more resources are available. C-SN 106A performs 358 the addition, replacement (i.e., modification) or cancellation (i.e., release) of the CG-Config IE or CG-CandidateInfo IE associated with the C-PSCell of UE 102. C-SN 106A sends 371 an SN Required message (e.g., SgNB Modify / Release Required or S-Node Modify / Release Required message), which may include an updated CG-CandidateList similar to event 360. In some implementations, the SN Required message includes a Conditional PSCell Add Information Required IE, which also includes a full list of currently prepared PSCells. Figure 3D or Figure 3ESimilarly, MN 104A updates 362 the C-SN configuration and performs 364 and 366 the RRC reconfiguration procedure with UE 102 to reconfigure the C-SN configuration. MN 104A sends 372 an SN confirmation message (e.g., an SgNB modification / release confirmation or an S-Node modification / release confirmation message) to C-SN 106A. In the case of a conditional SN change initiated by the SN, MN 104A may send 368 a conditional PSCell change cancellation message to S-SN 106B to inform S-SN 106B that the prepared PSCell list is cancelled in C-SN 106A. If UE 102 detects that the conditions for connecting to the C-PSCell are met, UE 102 performs 394 a conditional SN addition execution procedure. MN 104A, S-SN 106B, and C-SN 106A may then perform an SN release and SN state transfer procedure 396.

[0144] Figure 4 to Figure 8 300A to 300F described above may implement some or all of these methods. FIG. 4A to FIG. 4C Methods that an S-SN may implement to initiate a conditional SN change toward one or more C-SNs are respectively shown. FIG. 5A to FIG. 5D Methods that a MN may implement to perform a conditional SN change toward one or more C-SNs in response to a request from an S-SN are respectively shown. FIG. 6A to FIG. 6B A method that a MN may implement to maintain or reacquire execution conditions from an S-SN for C-SN configuration modifications is shown. Figure 7 Methods are shown that a MN may implement to perform SN modification during a CPAC procedure to provide a cell list prepared for some or all of the target SNs or a request for modification. Figure 8 Methods that a SN may implement to provide updated measurement configurations or execution conditions or execution modifications during a CPAC procedure are shown.

[0145] refer to Figure 4A , an S-SN (e.g., S-SN 106B) may implement method 400A to initiate a conditional SN change procedure with a MN (e.g., MN 104A) toward one or more C-SNs (e.g., C-SN 106A or 104B) using one or more CG-Configs for a UE (e.g., UE 102).

[0146] Specifically, at box 402, the S-SN determines to initiate a conditional SN change. At box 404, the S-SN generates CG-Config IE 1, ..., N for target SNs (i.e., C-SNs) 1, ..., N, respectively, where N≥1. At box 406, the S-SN generates target SN information (e.g., IE) 1, ..., N including IDs 1, ..., N (i.e., T-SN IDs 1, ..., N) of target SNs 1, ..., N and CG-Config IE 1, ..., N for target SNs 1, ..., N, respectively. At box 408, the S-SN sends an SN change requirement message including target SN information 1, ..., N to the MN in response to the determination (e.g., event 303). At box 410, the S-SN may receive an SN modification request message (e.g., event 352) from the MN including a cell list prepared for some or all of the target SNs. At block 412, in response to 410, the S-SN sends an SN modification request confirmation message to the MN including one or more CG-Config IEs, each of which includes an updated measurement configuration (e.g., event 354). At block 414, the S-SN receives an SN change confirmation message from the MN in response to the SN change request message (e.g., event 309).

[0147] In some implementations, CG-Config IE 1, ..., N includes candidate cell information lists 1, ..., N for target SNs 1, ..., N. In some implementations, the candidate cell information list for a specific target SN includes 1) measurement results of candidate cells for immediate PCell change or CPC operation received from the UE (e.g., candidateCellInfoListSN) and / or 2) a candidate cell information list for CPC (e.g., candidateCellInfoListCPC or candidatesCellListCPC). The candidate cell information list for CPC includes a list of candidate cells that the C-SN can select as the C-PSCell of the UE. In some implementations, for each of the candidate cells, the S-SN may include a trigger condition (e.g., condExecutionCondSCG or condExecutionCondSN IE) in the candidate cell information list.

[0148] In some implementations, the CG-Config IE for a specific target SN includes configuration parameters configured by the S-SN for the UE. Before initiating or determining to initiate a conditional SN change, the S-SN may send the configuration parameters to the UE directly (e.g., via SRB3) or via the MN. The S-SN communicates with the UE based on the configuration parameters. For example, the CG-Config IE may include an RRCReconfiguration message including the configuration parameters. In another example, the CG-Config IE includes a CellGroupConfig IE including the configuration parameters.

[0149] In some implementations, the S-SN may generate a container IE including target SN information 1, ..., N, and include the container IE in a new field or IE of the SN change required message.

[0150] In some implementations, the S-SN includes the SN to MN container IE in the SN change required message because the SN to MN container IE is a mandatory IE of the SN change required message according to 3GPP TS 36.423 and 38.423. In some implementations, the S-SN may generate a SN to MN container with a zero bit length to prevent the MN from using the SN to MN container IE. In other implementations, the S-SN includes the CG-Config IE in the SN to MN container IE, and the MN ignores or discards the CG-Config IE.

[0151] In some implementations, the MN includes a cell list prepared for some or all of the target SNs in the SN change confirmation message. In the case where the MN sends the SN modification request message of block 410, the MN may avoid including a cell list prepared for some or all of the target SNs in the SN change confirmation message. In such a case, the MN instead includes a cell list prepared for some or all of the target SNs in the SN change confirmation message.

[0152] Figure 4B is a flow chart of an example method 400B that is substantially similar to method 400A, except that method 400B includes blocks 407 and 409 instead of blocks 406 and 408 .

[0153] At block 407, the S-SN generates target SN information (e.g., IE) 1, ..., N including IDs 1, ..., N of the target SNs 1, ..., N, respectively, for the target SNs 1, ..., N. At block 409, the S-SN sends an SN change required message including target SN information 1, ..., N and CG-Config IEs 1, ..., N to the MN in response to the determination (e.g., event 303).

[0154] In some embodiments, the target SN information 1, ..., N and CG-Config IE 1, ..., N of block 409 are included in the SN change required message in the same sequence so that the MN can pair them based on the sequence (e.g., as in Figure 3C CG-Config IE 1, ..., N may be included in a container IE (e.g., as in Figure 3C In some implementations, the CG-Config IE 1, ..., N is included in a container IE that also includes companion T-SN ID 1, ..., N, so that the MN can pair the target SN information with the CG-Config (e.g., as in Figure 3C 4).

[0155] Figure 4C is a flow chart of an example method 400C that is substantially similar to methods 400A and 400B, except that method 400C includes blocks 405 and 411 instead of blocks 404 and 408 .

[0156] At block 405, the S-SN generates a single CG-Config IE for target SNs (i.e., C-SNs) 1, ..., N, respectively, where N ≥ 1. In some implementations, the S-SN includes candidate cell information lists 1, ..., N for target SNs 1, ..., N, respectively, in the CG-Config IE. At block 407, the S-SN generates target SN information 1, ..., N including IDs 1, ..., N of target SNs 1, ..., N, respectively, for target SNs 1, ..., N. At block 411, the S-SN sends an SN change requirement message including target SN information 1, ..., N and the CG-Config IE to the MN in response to the determination (e.g., event 303).

[0157] In some implementations, the candidate cell information in the CG-Config IE of block 405 includes a companion T-SN ID so that the MN can find the corresponding target SN for each candidate cell (e.g., as in Figure 3C 3).

[0158] Go to Figure 5A , a MN (e.g., MN 104A) may implement method 500A to perform a conditional SN change procedure initiated by an S-SN (e.g., S-SN 106B) to one or more C-SNs (e.g., C-SN 106A or 104B) of a UE (e.g., UE 102) using one or more CG-Configs for the UE (e.g., UE 102).

[0159] Method 500A starts at box 502, where the MN receives an SN change requirement message including target SN information (e.g., IE) 1, ..., N for target SNs 1, ..., N, respectively, from an S-SN, wherein the target SN information includes CG-Config IEs 1, ..., N and IDs 1, ..., N of the target SNs 1, ..., N, where N≥1. In some implementations, the CG-Config IEs 1, ..., N include candidate cell information lists 1, ..., N for the target SNs 1, ..., N, respectively (e.g., event 303). At box 504, the MN generates CG-ConfigInfo IEs 1, ..., N for the target SNs 1, ..., N, respectively, based on the CG-Config IEs. In some implementations, the MN includes the candidate cell information lists 1, ..., N in the CG-Config IEs 1, ..., N, respectively. In some implementations, the MN retrieves information from the candidate cell information list received from the S-SN, and includes the retrieved information in the candidate cell information list generated by the MN. In some implementations, the retrieved information does not include a trigger condition.

[0160] At block 506, the MN sends SN add request messages 1, ..., N including CG-ConfigInfo IEs 1, ..., N to the target SNs 1, ..., N, respectively (e.g., event 304 or 392). In some implementations, the MN determines addresses 1, ..., N of the target SNs 1, ..., N according to IDs 1, ..., N, and sends SN add request messages 1, ..., N to the addresses 1, ..., N of the target SNs, respectively. In some implementations, the addresses 1, ..., N may be IP addresses 1, ..., N, respectively. In such implementations, the MN may generate IP packets 1, ..., N, respectively, including the SN add request messages and the IP addresses 1, ..., N (i.e., as the destination IP addresses) and the IP address of the MN (i.e., as the source IP address), and send the IP packets on the interfaces with the target SNs 1, ..., N.

[0161] At box 508, the MN receives SN add request confirmation messages 1, ..., N including CG-CandidateList IE 1, ..., N from the target SN 1, ..., N, respectively. At box 510, the MN may send an SN modification request message including a cell list prepared for some or all of the target SNs to the S-SN (e.g., event 352). At box 512, the MN may receive an SN modification request confirmation message including one or more CG-Config IEs from the S-SN, each of which includes an updated measurement configuration (e.g., event 354). At box 514, the MN sends an SN change confirmation message to the S-SN in response to the SN change request message (e.g., event 309).

[0162] against Figure 4A The examples and implementations described can be applied to Figure 5A .

[0163] Figure 5B is a flow chart of an example method 500B that is substantially similar to method 500A, except that method 500B includes block 503 instead of block 502 .

[0164] At block 503, the MN receives an SN change request message including target SN information 1, ..., N and CG-Config IEs 1, ..., N for target SNs 1, ..., N, respectively, from the S-SN, where N ≥ 1 (e.g., event 303). The target SN information 1, ..., N includes IDs 1, ..., N of the target SNs 1, ..., N, respectively. To generate the CG-ConfigInfo IEs 1, ..., N, in some implementations, the MN associates candidate cell information with a specific target SN according to the sequence of CG-Config IEs that appear in the container IE (e.g., as in Figure 3C In other implementations, the MN associates the candidate cell information with a specific target SN according to the target SN ID included in the CG-Config IE (e.g., as in Figure 3C 4).

[0165] In some implementations, the S-SN may generate a container IE including target SN information 1, ..., N, and include the container IE in a new field or IE of the SN change required message.

[0166] In some implementations, the S-SN may include the SN to MN container IE in the SN change required message, because the SN to MN container IE is a mandatory IE of the SN change required message according to 3GPP TS 36.423 and 38.423. In some implementations, the S-SN may generate a SN to MN container with a zero bit length to prevent the MN from using the SN to MN container IE. In other implementations, the S-SN may include the CG-Config in the SN to MN container IE, and the MN ignores or discards the CG-Config IE.

[0167] In some implementations, the MN may include a cell list prepared for some or all of the target SNs in the SN change confirmation message. In the case where the MN sends the SN modification request message of block 410, the MN may avoid including a cell list prepared for some or all of the target SNs in the SN change confirmation message. In such a case, the MN instead includes a cell list prepared for some or all of the target SNs in the SN change confirmation message.

[0168] Figure 5C is a flow chart of an example method 500C that is substantially similar to methods 500A and 500B, except that method 500C includes blocks 505 and 507 instead of blocks 502 / 503 and 504 .

[0169] At block 505, the MN receives from the S-SN an SN change required message including target SN information 1, ..., N and a single CG-Config IE including a list of candidate cell information for the target SNs 1, ..., N, where N ≥ 1 (e.g., event 303). In some implementations, the target SN information 1, ..., N includes IDs 1, ..., N of the target SNs 1, ..., N, respectively, and the CG-Config IE includes target SN ID information (e.g., T-SN ID or CGI) and candidate cells (e.g., as in Figure 3C In other implementations, the target SN information 1, ..., N respectively includes the IDs 1, ..., N of the target SN 1, ..., N and the candidate cell PCI information list (for example, as in Figure 3C5). Using the information obtained at box 505, the MN can associate the candidate cell information with the specific target SN. The MN associates the candidate cell information with the specific target SN according to the target SN ID information included in the CG-Config or the cell PCI information included in the target SN 1, ..., N. The MN generates CG-ConfigInfo1, ..., N for the target SN 1, ..., N, respectively, wherein each of CG-ConfigInfo1, ..., N includes a corresponding candidate cell information list from CG-Config for the specific target SN. At box 507, the MN generates CG-ConfigInfo IE 1, ..., N with corresponding candidate cell information for the target SN 1, ..., N based on the CG-Config IE.

[0170] In some implementations, the S-SN may generate a container IE including target SN information 1, ..., N, and include the container IE in a new field or IE of the SN change required message.

[0171] In some implementations, the S-SN may include the SN to MN container IE in the SN change required message, because the SN to MN container IE is a mandatory IE of the SN change required message according to 3GPP TS 36.423 and 38.423. In some implementations, the S-SN may generate a SN to MN container with a zero bit length to prevent the MN from using the SN to MN container IE. In other implementations, the S-SN may include the CG-Config in the SN to MN container IE, and the MN ignores or discards the CG-Config IE.

[0172] In some implementations, the MN may include a cell list prepared for some or all of the target SNs in the SN change confirmation message. In the case where the MN sends the SN modification request message of block 410, the MN may avoid including a cell list prepared for some or all of the target SNs in the SN change confirmation message. In such a case, the MN instead includes a cell list prepared for some or all of the target SNs in the SN change confirmation message.

[0173] Figure 5D is a flow chart of an example method 500D that is substantially similar to methods 500A to 500C, except that method 500D includes additional blocks 501 and 511 and blocks 509 and 507 instead of blocks 502 / 503 / 505 and 504. Unlike methods 500A to 500C, in method 500D, the MN does not rely on information provided in the SN Change Required message to figure out corresponding candidate cells and target SNs.

[0174] At block 501, the MN may maintain a relationship between the served cell PCI, CGI, and / or neighboring RAN node ID (e.g., a data structure or mapping table of cell CGI and PCI of neighboring cells belonging to neighboring nodes, such as in Figure 3C 7). In some implementations, for box 501, the MN maintains the relationship of the paired cell CGI and PCI of the neighboring node via, for example, an Xn or X2 setup procedure, an NG-RAN node configuration update procedure, an eNB configuration update procedure, or a CGI report from the UE. At box 509, the MN receives from the S-SN an SN change request message including target SN information 1, ..., N having IDs 1, ..., N, respectively, and a single CG-Config IE including a list of candidate cell information for target SNs 1, ..., N having only cell PCIs, where N≥1 (e.g., event 303). At box 511, using the maintained relationship, the MN, for example, searches a mapping table for the received candidate cell information with PCI, and finds the corresponding CGI and the target SN to which each candidate cell belongs (e.g., as in Figure 3C In the example implementation 7). At box 507, the MN generates CG-ConfigInfo1, ..., N for target SN1, ..., N respectively, wherein each of CG-ConfigInfo 1, ..., N includes a corresponding candidate cell information list from the CG-Config IE for a specific target SN.

[0175] In other implementations, the MN generates CG-ConfigInfo 1, ..., N for target SNs 1, ..., N, respectively, wherein each of CG-ConfigInfo 1, ..., N includes the same full candidate cell information list from the CG-Config IE for all target SNs. In this case, each of the target SNs finds the candidate cell operated by the target SN from the list.

[0176] Next reference Fig. 6A , a MN (e.g., MN 104A) may implement method 600A to perform a conditional SN change procedure initiated by an S-SN (e.g., S-SN 106B) toward one or more C-SNs (e.g., C-SN 106A or 104B) for a UE (e.g., UE 102), and maintain execution conditions for C-SN configuration modification.

[0177] Method 600A begins at box 602, where the MN receives an SN change request message including candidate cell IDs 1, ..., K and execution conditions 1, ..., K for a target SN from an S-SN, where K≥1 (e.g., event 303). In some implementations, the SN change request message includes similar information for one or more target SNs, as described for methods 400A to 400C and 500A to 500D. At box 604, the MN sends an SN add request message including a CG-ConfigInfo including candidate cell IDs 1, ..., K to the target SN (e.g., event 304). At box 606, the MN receives an SN add request confirmation message including a CG-CandidateList with accepted candidate cell IDs 1, ..., M from the target SN, where 1≤M<K (e.g., event 308). At block 608, the MN configures the conditional configuration for the prepared candidate cells with cell IDs 1, ..., M to the UE, and stores the execution conditions for the candidate cell IDs M+1, M+2, ..., K. The process proceeds to block 610 or block 612. At block 610, the MN receives an SN modification requirement message including additional conditional configurations for additional candidate cells with cell IDs M+1, M+2, ..., O from the target SN, where O≤K (e.g., event 371). At block 612, the MN sends an SN modification request message to the target SN to update the previous conditional configuration (e.g., the maximum number of PSCells that can be prepared by the target SN) (e.g., event 356). At block 614, the MN receives an SN modification request confirmation message including additional conditional configurations for additional candidate cells with cell IDs M+1, M+2, ..., O from the target SN, where O≤K (e.g., event 360). At block 616, the MN configures the UE with additional conditional configurations for the additional candidate cells and the stored execution conditions M+1, M+2, ..., O (eg, event 364).

[0178] Figure 6B is a flow chart of an example method 600B that is substantially similar to method 600A, except that method 600B includes blocks 607 , 615 , 617 , 618 instead of blocks 608 and 616 .

[0179] At box 607, the MN configures the conditional configuration for the prepared candidate cells to the UE (without storing the execution conditions for the candidate cell IDs M+1, M+2, ..., K. At box 615, the MN sends an SN modification request message including additional candidate cells with cell IDs M+1, M+2, ..., O to the S-SN, where O≤K. At box 617, the MN receives an SN modification request confirmation message in response to the SN modification request message from the S-SN to provide the execution conditions M+1, M+2, ..., O. At box 618, the MN configures the additional conditional configuration for the additional candidate cells and the re-acquired execution conditions M+1, M+2, ..., O to the UE (e.g., event 364).

[0180] Next reference Figure 7 , a MN (eg, MN 104A) may implement method 700 to perform a conditional SN procedure for a UE (eg, UE 102) and a SN (eg, S-SN 106B or C-SN 106A or 104B).

[0181] Method 700 begins at box 702, where the MN determines to send an SN modification request message to the SN for the UE to perform a conditional SN process (e.g., event 352 or 356). At box 704, the MN determines whether to include a cell list prepared for some or all of the target SNs in the SN modification request message. If the MN determines that a cell list prepared for some or all of the target SNs is not included, the process proceeds to box 706, where the MN includes a conditional PSCell addition information modification request IE in the SN modification request message. At box 708, the MN sends an SN modification request message to the SN (e.g., event 356). At box 710, the MN receives an SN modification request confirmation message including a CG-CandidateList IE from the SN.

[0182] If the MN determines to include a cell list prepared for some or all of the target SNs, the process proceeds to block 712, where the MN includes the cell list prepared for some or all of the target SNs in a conditional PSCell change information update IE and includes the conditional PSCell change information update IE in the SN modification request message. At block 714, the MN sends an SN modification request message to the SN (e.g., event 352). At block 716, the MN receives an SN modification request confirmation including a CG-Config IE from the SN. In some implementations, at block 716, the MN receives an SN modification request confirmation including one or more CG-Config IEs in a separate RRC container.

[0183] Next reference Figure 8, a SN (eg, S-SN 106B or C-SN 106A or 104B) may implement method 800 to perform a conditional SN procedure for a UE (eg, UE 102) and a MN (eg, MN 104A).

[0184] Method 800 begins at box 802, where the SN receives an SN modification request message for a conditional SN procedure from a MN for a UE (e.g., event 352 or 356). At box 804, the SN determines whether the SN modification request message includes a conditional PSCell addition information modification request IE. If the SN determines that the SN modification request message does not include a conditional PSCell addition information modification request IE, the process proceeds to box 806, where the SN generates a CG-Config IE. Then at box 808, the SN sends an SN modification request confirmation including a CG-Config IE to the MN (e.g., event 354). If the SN determines that the SN modification request message includes a conditional PSCell addition information modification request IE, the process proceeds to box 810, where the SN generates a CG-CandidiateList IE. Then at box 812, an SN modification request confirmation including a CG-CandidateList IE is sent to the MN (e.g., event 360).

[0185] In some implementations, the SN modification request message includes a conditional PSCell add information modification request IE. In other implementations, the SN modification request message includes a conditional PSCell change information update IE.

[0186] In some implementations, the RAN node generates one or more containers at block 806, each of which includes a specific CG-Config IE, and includes the one or more containers in the SN modification request confirmation message at block 808. In some implementations, the RAN node generates a single container at block 806 to include a single CG-Config IE, and includes the container in the SN modification request confirmation message at block 808.

[0187] In some implementations, the RAN node includes the CG-Config IE in the CG-CandidateList IE in the SN Modification Request Confirm message at block 810. In some implementations, the container may be a cg-CandidateList field, a cg-CandidateList field-r17, a CG-CandidateList-IEs IE, a CG-CandidateList-r17IE, a cg-CandidateToAddModList field, a cg-CandidateToAddModList fiel d-r17, a CG-CandidateToAddModList-r17 IE.

[0188] The following description can be applied to the above description.

[0189] In general, the description of one of the above figures may apply to another of the above figures. The events or boxes described above may be optional or omitted. For example, the events or boxes with dotted lines in the figures may be optional. In some implementations, "message" is used and "information element (IE)" can be used to replace "message". In some implementations, "IE" is used and "field" can be used to replace "IE". In some implementations, "configuration" or "configuration parameter" can be used to replace "CG-CandidateInfo ID". In some implementations, "CG-Config ID" or another IE name can be used to replace "CG-CandidateInfo ID".

[0190] The user device (e.g., UE 102) in which the technology of the present disclosure can be implemented can be any suitable device capable of wireless communication, such as a smart phone, a tablet computer, a laptop computer, a mobile game console, a point of sale (POS) terminal, a health monitoring device, a drone, a camera, a media streaming dongle or another personal media device, a wearable device (such as a smart watch), a wireless hotspot, a femtocell or a broadband router. In addition, in some cases, the user device can be embedded in an electronic system (such as a head unit of a vehicle or an advanced driver assistance system (ADAS)). Further, the user device can be operated 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.

[0191] Certain embodiments are described in the present disclosure as including logic or multiple components or modules. A module may be a software module (e.g., a code or machine-readable instruction stored on a non-temporary machine-readable medium) or a hardware module. A hardware module is a tangible unit that is capable of performing certain operations and may be configured or arranged in a certain manner. A hardware module may include a dedicated circuit system 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 an application-specific integrated circuit (ASIC), a digital signal processor (DSP), etc.). A hardware module may also include a programmable logic or circuit system that is temporarily configured by software to perform certain operations (e.g., as contained in a general-purpose processor or other programmable processor). The decision to implement a hardware module in a dedicated and permanently configured circuit system or in a temporarily configured circuit system (e.g., configured by software) may be driven by cost and time considerations.

[0192] When implemented in software, the techniques may be provided as part of an operating system, a library used by multiple applications, 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 in a master mode (MN) providing a dual connectivity (DC) connection to a user equipment (UE) with a source secondary node (S-SN), the method comprising: receiving, from the S-SN, a first message indicating that the UE requires a change of the SN, the message comprising a plurality of information elements (IEs) for a plurality of target SNs, the UE being connected to one of the plurality of target SNs after a corresponding condition is satisfied, each of the IEs comprising an identifier of a corresponding one of the plurality of target SNs; as well as A second message is sent to the S-SN indicating that the change of the SN is confirmed.

2. The method of claim 1, further comprising: In response to determining that the first message includes the IE for the plurality of target SNs: The target S-NG-RAN node identifier information IE included in the first message is ignored.

3. The method according to claim 1 or 2, further comprising: In response to determining that the first message includes the IE for the plurality of target SNs: The S-NG-RAN node to M-NG-RAN node container IE included in the first message is ignored.

4. A method as claimed in any one of the preceding claims, wherein: The first message includes candidate cell information related to the multiple target SNs. The method of claim 4 , wherein the candidate cell information is included in a CG-Config IE. The method of claim 5 , wherein the candidate cell information is included in an RRC container.

7. The method according to any one of claims 4 to 6, wherein the candidate cell information includes a trigger condition of the corresponding candidate cell.

8. A method as claimed in any one of the preceding claims, wherein: The first message is an S-Node change request message.

9. A method as claimed in any one of the preceding claims, wherein: The first message is an SgNB change request message.

10. A method in a source secondary node (S-SN) providing a dual connectivity (DC) connection to a user equipment (UE) with a master node (MN), the method comprising: sending a first message to the MN indicating that the UE requires a change of the SN, the message comprising a plurality of information elements (IEs) for a plurality of target SNs, the UE connecting to one of the plurality of target SNs after a corresponding condition is satisfied, each of the IEs comprising an identifier of a corresponding one of the plurality of target SNs; as well as A second message is received from the MN indicating that the change of the SN is confirmed.

11. The method of claim 10, wherein: The first message includes candidate cell information related to the multiple target SNs.

12. The method of claim 11, wherein the candidate cell information is included in a CG-Config IE.

13. The method of claim 12, wherein the candidate cell information is included in an RRC container.

14. The method according to any one of claims 11 to 13, wherein the candidate cell information comprises a trigger condition of the corresponding candidate cell.

15. A node in a Radio Access Network (RAN) comprising processing hardware and configured to implement the method according to any one of the pending claims.

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