Add and modify conditional configurations at user devices

Abstract

The base stations and user equipment (UE) of the present disclosure implement techniques for managing conditional configurations, which enable the UE to determine whether, when the UE receives a conditional configuration from a base station on the RAN, the UE should add the received configuration as a new configuration or instead use the received configuration to modify an existing configuration. In various embodiments, the RAN may provide the UE with a configuration identifier for this purpose, or may provide the UE with a complete list of conditional configurations whenever the RAN configures the UE for a conditional procedure.

Description

[0001] The present disclosure relates generally to wireless communications and, more particularly, to conditional procedures such as conditional handover and conditional auxiliary node addition procedures. Background Art

[0002] This background description is provided to generally present the context of the present disclosure. To the extent described in this background section, the work of the presently named inventors and aspects of the description that may not otherwise be prior art at the time of filing are neither explicitly nor implicitly admitted as prior art against the present disclosure.

[0003] In telecommunications systems, the Packet Data Convergence Protocol (PDCP) sublayer of the radio protocol stack provides services such as transport, encryption, and integrity protection of user plane data. For example, the PDCP layer, defined for the Evolved Universal Terrestrial Radio Access (EUTRA) radio interface (see 3GPP specification TS 36.323) and New Radio (NR) (see 3GPP specification TS 38.323), provides sequencing of protocol data units (PDUs) in the uplink direction (from a user device (also known as user equipment (UE)) to a base station) and in the downlink direction (from a base station to a UE). In addition, the PDCP sublayer provides signaling radio bearers (SRBs) and data radio bearers (DRBs) to the radio resource control (RRC) sublayer. Generally speaking, the UE and the base station can use SRBs to exchange RRC messages and non-access stratum (NAS) messages, and can use DRBs to transport data on the user plane.

[0004] There are several types of SRBs and DRBs that a UE can use. When operating with dual connectivity (DC), cells associated with a base station operating a master node (MN) define a master cell group (MCG), while cells associated with a base station operating as a secondary node (SN) define a secondary cell group (SCG). So-called SRB1 resources carry RRC messages, which in some cases include NAS messages over a dedicated control channel (DCCH), while SRB2 resources support RRC messages, which include logged measurement information or NAS messages, also over the DCCH but with a lower priority than SRB1 resources. More generally, SRB1 and SRB2 resources allow the UE and MN to exchange RRC messages related to the MN and embedded RRC messages related to the SN, and may also be referred to as MCG SRBs. SRB3 resources allow the UE and SN to exchange RRC messages related to the SN, and may be referred to as SCG SRBs. Split SRBs allow the UE to exchange RRC messages directly with the MN via the lower layer resources of the MN and SN. In addition, a DRB that terminates at an MN and uses only the lower layer resources of the MN may be referred to as an MCG DRB, a DRB that terminates at an SN and uses only the lower layer resources of the SN may be referred to as an SCG DRB, and a DRB that terminates at an MCG but uses the lower layer resources of the MN, SN, or both the MN and the SN may be referred to as a split DRB.

[0005] 3GPP specification TS 37.340 (v15.7.0) describes the procedures for a UE to add or change a SN in a DC scenario. These procedures involve messaging (e.g., RRC signaling and preparation) between radio access network (RAN) nodes. This messaging typically results in latency, which in turn increases the probability of failure of the SN add or SN change procedure. These procedures, which do not involve checking conditions at the UE, can be referred to as "immediate" SN add and SN change procedures.

[0006] The UE may also perform a handover procedure to switch from one cell to another, whether in single connectivity (SC) or DC operation. Depending on the scenario, the UE may switch from a cell of a first base station to a cell of a second base station, or from a cell of a first distributed unit (DU) of a base station to a cell of a second DU of the same base station. 3GPP specifications 36.300 v15.6.0 and 38.300 v15.6.0 describe a handover procedure that includes several steps (RRC signaling and preparation) between RAN nodes, which results in latency in the handover procedure and, therefore, increases the risk of handover failure. This procedure, which does not involve conditions checked at the UE, may be referred to as an "immediate" handover procedure.

[0007] Recently, "conditional" procedures (i.e., conditional SN addition / change and conditional switching) have been considered for SN addition / change and switching. Unlike the "immediate" procedures discussed above, these procedures do not add or change the SN, or perform switching, 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 specific signal quality metric exceeding a threshold), or a logical combination of such states or events (e.g., "condition A and condition B" or "(condition A or condition B) and condition C", etc.). In addition, the term "condition" may be used herein to refer to a condition in the abstract (e.g., signal quality is in a specific state), or to refer to a condition configuration (e.g., a digital representation / expression of a condition that can be sent and stored, etc.).

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

[0009] In some scenarios, the UE may store multiple configurations associated with different conditional candidate RAN nodes or different candidate cells. In addition, the UE may modify or release / remove these stored configurations. However, currently, when the RAN sends a configuration for a conditional procedure to the UE, the UE cannot reliably and consistently determine whether the UE should use the received configuration to modify the current configuration or should add the received configuration as a new configuration. As a result, the UE may be incorrectly configured at any given time (e.g., in a manner that does not conform to the network state expected by the RAN). Furthermore, base stations are currently not equipped with any appropriate way to manage configurations for conditional procedures. Both of these issues can lead to significant network inefficiencies (e.g., lower network capacity or average data rate, more radio link failures, etc.). Summary of the Invention

[0010] The base station and UE of the present disclosure implement techniques that enable the UE to determine whether, when the UE receives a conditional configuration from a base station of a RAN, the UE should (1) add the received configuration as a new configuration or instead (2) use the received configuration to modify an existing configuration (i.e., modify a configuration that is already stored at the UE and has not yet been released by the UE). As used herein, the term "conditional configuration" refers to a configuration that is associated with a condition that must be met before the UE can use the configuration to communicate with a candidate base station or via a candidate cell. For example, using these techniques, the UE can determine whether the UE should add a newly received configuration associated with a candidate SN (C-SN) as a new configuration or use the received configuration to modify another conditional configuration already stored at the UE. In other implementations and / or scenarios, the UE can determine whether the UE should add a received configuration associated with a candidate handover / target cell as a new configuration or instead use the received configuration to modify another conditional configuration already stored at the UE.

[0011] In some implementations, the RAN notifies the UE whether a newly sent configuration is a new configuration or a change to an existing configuration by using a configuration identifier. After the RAN assigns a configuration identifier to a particular configuration and sends the identifier and configuration to the UE, the UE can check the identifier to add or modify the configuration appropriately. As used herein, and unless a more specific meaning is clear from the context in which it is used, "assigning" a configuration identifier can refer to the act of initially selecting an identifier (i.e., for a completely new configuration), or to the subsequent selection of a previously selected / used identifier (i.e., when the RAN attempts to modify an existing configuration). In various implementations, the configuration identifier can be an information element that the RAN also uses for other purposes (e.g., a transaction ID, a cell ID, or a measurement identifier), or can be an information element dedicated to the purpose of identifying / managing conditional configurations. The RAN can also use the configuration identifier to indicate to the UE which configurations should be released.

[0012] In other implementations, whenever the RAN decides to send a conditional configuration to the UE, and regardless of whether the conditional configuration is a new configuration or a change to an existing configuration, the RAN sends the entire set of conditional configurations to the UE (e.g., all conditional configurations that the RAN previously sent to the UE and has not yet instructed the UE to release). Thus, the UE can simply replace all existing configurations with all configurations in the received set, rather than having to determine whether the newly received configuration corresponds to (i.e., is intended to be changed to) a specific existing configuration.

[0013] One example implementation of these techniques is a method in a user device in communication with a base station. The method includes receiving, by processing hardware of the user device, from the base station (i) a configuration associated with conditions to be satisfied before the user device can use the configuration to communicate with a candidate base station or via a candidate cell and (ii) a configuration identifier. The method also includes determining, by the processing hardware and based on the configuration identifier, whether the configuration corresponds to any pre-existing configuration stored in the user device. The method also includes (i) storing, by the processing hardware, the configuration as a new configuration in the user device or (ii) using the configuration to modify a pre-existing configuration already stored in the user device based on whether the configuration corresponds to any pre-existing configuration stored in the user device.

[0014] Another example implementation of these techniques is a method in a user device configured to store configurations for communicating with a candidate base station or communicating via a candidate cell. The method includes receiving, by processing hardware of the user device, a conditional configuration set consisting of one or more configurations from a RAN. Each of the one or more configurations is associated with (i) a corresponding candidate base station or a corresponding candidate cell and (ii) a corresponding condition to be satisfied before the user device can communicate with the corresponding candidate base station or communicate via the corresponding candidate cell according to a first type of conditional procedure. The method also includes: in response to receiving the conditional configuration set, replacing (i) all pre-existing configurations stored in the user device and associated with the condition to be satisfied before the user device can communicate with a particular candidate base station or communicate via a particular candidate cell according to the first type of conditional procedure with (ii) one or more configurations in the conditional configuration set, regardless of whether any configuration in the conditional configuration set corresponds to any pre-existing configuration.

[0015] Another example implementation of these techniques is a method that includes determining, by processing hardware of a RAN, a configuration conditional process that enables a user device to conditionally communicate with a candidate base station of the RAN or via a candidate cell of the RAN. The method also includes assigning, by the processing hardware, a configuration identifier to a configuration associated with (i) the candidate base station or candidate cell and (ii) a condition to be satisfied before the user device can use the configuration to communicate with the candidate base station or via the candidate cell. The method also includes causing the user device, at least by sending the configuration and the configuration identifier to the user device, to (i) store the configuration as a new configuration or (ii) use the configuration to modify a pre-existing configuration stored at the user device based on the configuration identifier.

[0016] Another example implementation of these techniques is a method in a RAN that includes maintaining, by processing hardware of the RAN, a set of conditional configurations. The set includes all unreleased configurations associated with (i) a user device and (ii) a condition to be satisfied before the user device can communicate with a corresponding candidate base station or via a corresponding candidate cell according to a first type of conditional procedure. The method also includes determining, by the processing hardware, to configure a first conditional procedure of a first type that enables the user device to conditionally communicate with a first candidate base station of the RAN or via a first candidate cell of the RAN. The method also includes adding, by the processing hardware, a first configuration to the set of conditional configurations, the first configuration associated with (i) the first candidate base station or the first candidate cell and (ii) the condition to be satisfied before the user device can communicate with the first candidate base station or via the first candidate cell using the first configuration and according to the first type of conditional procedure. The method also includes, after adding the first configuration, causing the user device to replace (i) all pre-existing configurations stored in the user device and associated with the condition to be satisfied before the user device can communicate with a particular candidate base station or via a particular candidate cell according to the first type of conditional procedure with (ii) all configurations in the set of conditional configurations, at least by sending the set of conditional configurations to the user device. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1A and 1B is a block diagram of an example system in which a radio access network (RAN) and a user equipment (UE) may implement the presently disclosed techniques for managing configuration associated with conditional handover and / or conditional secondary node (SN) add / change procedures;

[0018] Figure 1C is a block diagram of an example base station where a centralized unit (CU) and a distributed unit (DU) may be located in Figure 1A or Figure 1B Operate in the system;

[0019] FIG2 is a block diagram of an example protocol stack, according to which Figure 1A or Figure 1B The UE can be used with Figure 1A or Figure 1B Base station communication;

[0020] Figures 3A to 3C is an example message sequence corresponding to a scenario and / or implementation where the RAN and UE use a transaction ID as a configuration identifier for a conditional handover procedure;

[0021] Figure 4A and 4B is an example message sequence corresponding to a scenario and / or implementation where the RAN and UE use the cell ID as a configuration identifier for the conditional handover procedure;

[0022] Figures 5A to 5D is an example message sequence corresponding to a scenario and / or implementation of a dedicated configuration identifier for a conditional handover procedure used by the RAN and the UE;

[0023] Figures 6A to 6C is an example message sequence corresponding to a scenario and / or implementation where the RAN and UE use a transaction ID as a configuration identifier for a conditional SN add or SN change procedure;

[0024] Figures 7A to 7C is an example message sequence corresponding to a scenario and / or implementation where the RAN and UE use the cell ID as a configuration identifier for a conditional SN add or SN change procedure;

[0025] Figures 8A to 8F is an example message sequence corresponding to a scenario and / or implementation of a dedicated configuration identifier for use of a conditional SN add or SN change procedure by the RAN and the UE;

[0026] Figures 9A to 9C is an example message sequence corresponding to a scenario and / or implementation where the RAN and UE use a configuration identifier to release a conditional configuration;

[0027] Figure 10A and 10B is an example message sequence corresponding to a scenario and / or implementation in which the RAN provides a full set of conditional handover configurations to the UE;

[0028] Figures 11A to 11D is an example message sequence corresponding to a scenario and / or implementation in which the RAN provides a full set of conditional SN configurations to the UE;

[0029] Figure 12 is a flow chart depicting an example method implemented in a user device to maintain a correct set of conditional configurations using configuration identifiers;

[0030] Figure 13 is a flow chart depicting an example method implemented in a RAN using a configuration identifier to facilitate maintaining a correct set of conditional configurations at a user device;

[0031] Figure 14 is a flow chart depicting an alternative example method of maintaining a correct set of condition configurations implemented in a user device; and

[0032] Figure 15 is a flow chart depicting an alternative example method implemented in a RAN that facilitates maintaining a correct set of conditional configurations at a user device. DETAILED DESCRIPTION

[0033] Figure 1AAn example wireless communication system 100 is depicted in which the conditional configuration management techniques of the present disclosure may be implemented. Wireless communication system 100 includes a UE 102 and base stations 104A, 106A, and 106B connected to a core network (CN) 110. Base stations 104A, 106A, and 106B may be any suitable type or types of base stations, such as, for example, an evolved Node B (eNB), a next-generation eNB (ng-eNB), or a 5G Node B (gNB). As just one more specific example, base station 104A may be an eNB or a gNB, while base stations 106A and 106B may be gNBs.

[0034] Base station 104A supports cell 124A, base station 106A supports cell 126A, and base station 106B supports cell 126B. Cell 124A partially overlaps with both cells 126A and 126B, so that UE 102 can be within the range of communicating with base station 106A while being within the range of communicating with base station 106A or 106B (or within the range of detecting or measuring signals from both base stations 104A and 106A, etc.). The overlap enables UE 102 to switch between cells (e.g., from cell 124A to cell 126A or 126B) before UE 102 experiences a radio link failure. In addition, the overlap allows for various dual connectivity (DC) scenarios discussed below. For example, UE 102 can communicate with base station 104A (operating as a MN) and base station 106A (operating as a SN) in DC, and upon completing an SN change, can communicate with base station 104A (operating as a MN) and base station 106B (operating as a SN). More specifically, when the UE 102 is in DC with the base station 104A and the base station 106A, the base station 104A operates as a MeNB, Mng-eNB, or MgNB, and the base station 106A operates as an SgNB or Sng-eNB. In implementations and scenarios where the UE 102 is in SC with the base station 104A but is capable of DC operation, the base station 104A operates as a MeNB, Mng-eNB, or MgNB, and the base station 106A operates as a candidate SgNB (C-SgNB) or candidate Sng-eNB (C-Sng-eNB). Although various scenarios are described below in which the base station 104A operates as a MN and the base station 106A (or 106B) operates as a SN or C-SN, any of the base stations 104A, 106A, and 106B can generally operate as a MN, SN, or C-SN in different scenarios. Thus, in some implementations, base station 104A, base station 106A, and base station 106B may implement a similar set of functions and each support MN, SN, and C-SN operations.

[0035] In operation, UE 102 may utilize radio bearers (e.g., DRBs or SRBs) that terminate at different times at a MN (e.g., base station 104A) or a SN (e.g., base station 106A). UE 102 may apply one or more security keys when communicating on the radio bearers in the uplink (from UE 102 to the base station) and / or downlink (from the base station to UE 102) directions.

[0036] Base station 104A includes processing hardware 130, which may include one or more general-purpose processors (e.g., central processing units (CPUs)) and computer-readable memory storing machine-readable instructions executable on the general-purpose processors and / or special-purpose processing units. Figure 1A The processing hardware 130 in the example implementation of includes a base station RRC controller 132 configured to manage or control RRC procedures and RRC configuration. For example, the base station RRC controller 132 can be configured to support RRC messaging associated with immediate and conditional handover procedures and / or support necessary operations when the base station 104A operates as a MN, as described below. Furthermore, in some implementations and / or scenarios, the base station RRC controller 132 can be responsible for maintaining (for UE 102 and Figure 1A Multiple other UEs not shown in the current condition configuration set.

[0037] The base station 106A includes processing hardware 140, which may include one or more general-purpose processors (eg, CPUs) and computer-readable memory storing machine-readable instructions executable on the general-purpose processors and / or special-purpose processing units. Figure 1A The processing hardware 140 in the example implementation of includes a base station RRC controller 142 configured to manage or control RRC procedures and RRC configuration. For example, the base station RRC controller 142 can be configured to support RRC messaging associated with immediate and conditional handover procedures and / or support necessary operations when the base station 106A operates as a SN or a candidate SN (C-SN), as described below. Furthermore, in some implementations and / or scenarios, the base station RRC controller 142 can be responsible for maintaining (for UE 102 and Figure 1A Multiple other UEs not shown in the figure) have current condition configuration sets. Figure 1A Not shown, but base station 106B may include processing hardware similar to processing hardware 140 of base station 106A.

[0038] UE 102 includes processing hardware 150, which may include one or more general-purpose processors (eg, CPUs) and computer-readable memory storing machine-readable instructions executable on the general-purpose processors and / or special-purpose processing units. Figure 1AThe processing hardware 150 in an example implementation of includes a UE RRC controller 152 configured to manage or control RRC procedures and RRC configurations. For example, the UE RRC controller 152 may be configured to support RRC messaging associated with immediate and conditional handover and / or secondary node addition / modification procedures, and may also be responsible for maintaining a current set of conditional configurations for the UE 102 (e.g., adding, releasing, or modifying conditional configurations as needed) in accordance with any of the implementations discussed below.

[0039] CN 110 can be either Evolved Packet Core (EPC) 111 or Fifth Generation Core (5GC) 160, both of which are Figure 1A 160. The base station 104A may be 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 an EN-DC gNB (en-gNB) with 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 exchange messages directly with each other during the various scenarios discussed below, the base stations 104A, 106A, 106B may support an X2 or Xn interface.

[0040] Among other components, the EPC 111 may include a serving gateway (S-GW) 112 and a mobility management entity (MME) 114. The S-GW 112 is typically configured to transfer user plane packets related to audio calls, video calls, internet services, etc., and the MME 114 is typically configured to manage authentication, registration, paging, and other related functions. 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. The UPF 162 is typically configured to transfer user plane packets related to audio calls, video calls, internet services, etc., the AMF 164 is typically configured to manage authentication, registration, paging, and other related functions, and the SMF 166 is typically configured to manage PDU sessions.

[0041] In general, the wireless communication system 100 may include any suitable number of base stations supporting NR cells and / or EUTRA cells. More specifically, the EPC 111 or the 5GC 160 may be connected to any suitable number of base stations supporting NR cells and / or EUTRA cells. For example, in the following reference Figure 1BAdditional base stations are considered in the immediate and conditional handover scenarios discussed. Although the examples below specifically relate to specific CN types (EPC, 5GC) and RAT types (5G NR and EUTRA), the techniques of the present disclosure may also be generally applicable to other suitable radio access and / or core network technologies, such as, for example, sixth generation (6G) radio access and / or 6G core network or 5G NR-6G DC.

[0042] As described above, the wireless communication system 100 may support various procedures (eg, handover, SN addition, etc.) and operation modes (eg, SC or DC). Example operations of the various procedures that may be implemented in the wireless communication system 100 will now be described.

[0043] In some implementations, the wireless communication system 100 supports immediate handover between cells. In one scenario, for example, UE 102 initially connects to base station 104A, and base station 104A later performs preparations for immediate handover with base station 106A via an interface (e.g., X2 or Xn). In this scenario, base stations 104A and 106A operate as a source base station and a target base station, respectively. In handover preparation, source base station 104A sends a handover request message to target base station 106A. In response, target base station 106A includes an immediate handover command message in a handover request confirmation message and sends the handover request confirmation message to source base station 104A. Then, in response to receiving the handover request confirmation message, source base station 104A sends a handover command message to UE 102.

[0044] Upon receiving the immediate handover command message, UE 102 immediately reacts to the immediate handover command by attempting to connect to target base station 106A. To connect to target base station 106A, UE 102 may perform a random access procedure with target base station 106A and then (after gaining access to a control channel) (i.e., in response to the immediate handover command) send a handover complete message to target base station 106A via the cell of base station 106A.

[0045] In some implementations, the wireless communication system 100 also supports conditional handover. In one scenario, for example, UE 102 initially connects to base station 104A, and base station 104A later performs a first conditional handover preparation process with base station 106A via an interface (e.g., X2 or Xn) to prepare for a potential handover of UE 102 to base station 106A. In this scenario, base stations 104A and 106A operate a source base station and a target base station, respectively. During the first conditional handover preparation process, source base station 104A sends a handover request message to candidate base station 106A. In response, candidate base station 106A includes a first conditional handover command message in a handover request confirmation message and sends the handover request confirmation message to source base station 104A. Then, in response to receiving the handover request confirmation message, source base station 104A sends the first conditional handover command message to UE 102.

[0046] Upon receiving the first conditional handover command message, UE 102 does not immediately react to the first conditional handover command message by attempting to connect to candidate base station 106A. Instead, only when UE 102 determines that the first condition for handover to candidate cell 126A of candidate base station 106A is met does UE 102 connect to candidate base station 106A in accordance with the first conditional handover command message. Base station 106A provides a configuration for candidate cell 126A in the first conditional handover command message (i.e., a configuration that UE 102 can use to connect to base station 106A via candidate cell 126A).

[0047] Before the first condition is met, the UE 102 is not yet connected to the candidate base station 106A. In other words, the candidate base station 106A is not yet connected to and serving the UE 102. In some implementations, the first condition may be that the signal strength / quality measured by the UE 102 on the candidate cell 126A of the candidate base station 106A is sufficiently "good." For example, the first condition may be met if one or more measurement results obtained by the UE 102 (when performing measurements on the candidate cell 126A) are above a threshold configured by the source base station 104A, or above a predetermined or preconfigured threshold. If the UE 102 determines that the first condition is met, the candidate base station 106A becomes the target base station 106A for the UE 102, and the UE 102 attempts to connect to the target base station 106A. To connect to the target base station 106A, the UE 102 may perform a random access procedure with the target base station 106A and then (after obtaining access to a control channel) send a first handover complete message to the target base station 106A via the candidate cell 126A. After the UE 102 successfully completes the random access procedure and / or sends the first handover complete message, the target base station 106A becomes the source base station 106A for the UE 102, and the UE 102 begins communicating data with the source base station 106A.

[0048] In some implementations and / or scenarios, conditional handoff may occur for more than one candidate cell supported by candidate base station 106A (e.g., cell 126A and Figure 1A In one such scenario, in addition to the configuration of candidate cell 126A, base station 106A may also provide configurations of additional candidate cells for base station 106A in the first conditional handover command message. UE 102 may then monitor whether the additional candidate cells of candidate base station 106A meet the second condition, while also monitoring whether candidate cell 126A meets the first condition. The second condition may be the same as or different from the first condition.

[0049] In another scenario, base station 104A also performs a second conditional handover preparation procedure with base station 106A via an interface (e.g., X2 or Xn) to prepare for a potential handover of UE 102 to base station 106A in a process similar to the process described above. However, in this scenario, base station 104A also sends a second conditional handover command message received by base station 104A from candidate base station 106A to UE 102 for the potential handover in the second conditional handover preparation. Base station 106A may provide additional candidate cells ( Figure 1A UE 102 may monitor whether the additional candidate cells of candidate base station 106A meet a second condition. The second condition may be the same as or different from the first condition.

[0050] Base station 104A may also perform a third conditional handover preparation process with base station 106B via an interface (e.g., X2 or Xn) to prepare for a potential handover of UE 102 to base station 106B in a process similar to the process described above. In this scenario, base station 104A sends a third conditional handover command message received by base station 104A from candidate base station 106B to UE 102 for the potential handover in the third conditional handover preparation. Base station 106A may provide the configuration of candidate cell 126B in the third handover command message. UE 102 may monitor whether the candidate cell 126B of candidate base station 106B satisfies the third condition. The third condition may be the same as or different from the first and / or second condition. The conditional handover command message above may be an RRC reconfiguration message or may be replaced by a conditional handover configuration as an information element (IE).

[0051] In some implementations, the wireless communication system 100 supports DC operation, including SN addition and SN change procedures. In one scenario, for example, after UE 102 connects to base station 104A, base station 104A may perform an immediate SN addition procedure to add base station 106A as a secondary node, thereby configuring UE 102 to operate in DC with base stations 104A and 106A. At this point, base stations 104A and 106A operate as MN and SN, respectively. Later, when UE 102 is still in DC with MN 104A and SN 106A, MN 104A may perform an immediate SN change procedure to change the SN of UE 102 from base station 106A (which may be referred to as a source SN or S-SN) to base station 106B (which may be referred to as a target SN or T-SN).

[0052] In other scenarios, base station 104A may perform a conditional SN addition procedure to configure base station 106A as a candidate SN (C-SN) for UE 102 when UE 102 is in single connectivity (SC) with base station 104A, or when UE 102 is in DC with base stations 104A and 106B, and before UE 102 has connected to C-SN 106A. In this case, base stations 104A and 106A serve as the MN and C-SN of UE 102, respectively. When UE 102 receives the configuration of C-SN 106A, UE 102 does not connect to C-SN 106A unless and until UE 102 detects that a corresponding condition is met. If UE 102 determines that the condition is met, UE 102 connects to C-SN 106A, causing C-SN 106A to become SN 106A for UE 102.

[0053] In some implementations, the condition may be that the signal strength / quality measured by the UE 102 on the candidate primary secondary cell (C-PSCell) of the C-SN 106A is sufficiently "good." For example, if one or more measurement results obtained by the UE 102 (when performing measurements on the C-PSCell) are above a threshold configured by the MN 104A, or above a predetermined or preconfigured threshold, the first condition may be met. If the UE 102 determines that the first condition is met, the UE 102 may perform a random access procedure using the C-SN 106A to connect to the C-SN 106A. When the UE 102 successfully completes the random access procedure, the base station 106A becomes the SN of the UE 102, and the C-PSCell (e.g., cell 126A) becomes the PSCell of the UE 102. The SN 106A may then begin transmitting data with the UE 102.

[0054] Another scenario involves a conditional PSCell change. In this scenario, UE 102 is initially connected to MN 104 (via a primary cell (PCell)) and SN 106A (via a different cell than cell 126A). Figure 1A 126A is in DC. SN 106A may provide UE 102 with the configuration of C-PSCell 126A. If UE 102 is configured with a signaling radio bearer (SRB) that allows the exchange of RRC messages with SN 106A (e.g., SRB3), SN 106A may send the configuration of C-PSCell 126A to UE 102 directly via the SRB or via MN 104. For example, SN 106A may send the configuration in response to one or more measurement results received from UE 102 via the SRB or in response to one or more measurement results obtained by SN 106A from measurements of signals received from UE 102.

[0055] In contrast to the immediate PSCell change scenario discussed above, upon receiving the configuration of the C-PSCell 126A, the UE 102 does not immediately disconnect from the PSCell and attempt to connect to the C-PSCell 126A. Instead, the UE 102 does not connect to the C-PSCell 126A until the UE 102 determines that a certain condition has been met. When the UE 102 determines that the condition has been met, the UE 102 connects to the C-PSCell 126A, causing the C-PSCell 126A to begin operating as the PSCell 126A for the UE 102. In some implementations, the UE 102 disconnects from the PSCell in order to connect to the C-PSCell 126A.

[0056] In some scenarios, a condition associated with a conditional SN addition or conditional PSCell change may be that the signal strength / quality measured by UE 102 on the C-PSCell of C-SN 106A exceeds a certain threshold or otherwise corresponds to an acceptable measurement. For example, when one or more measurement results obtained by UE 102 on C-PSCell 126A exceed a threshold configured by MN 104 or C-SN 106A, or exceed a predetermined or preconfigured threshold, UE 102 may determine that the condition is met. When UE 102 determines that this condition is met, UE 102 may perform a random access procedure on C-PSCell 126A and with C-SN 106A to connect to C-PSCell 106A. When UE 102 successfully completes the random access procedure on C-PSCell 126A, C-PSCell 126A becomes PSCell 126A for UE 102. C-SN 106A may then begin communicating data (user plane data and / or control plane data) with UE 102 via PSCell 126A.

[0057] In different configurations or scenarios of the wireless communication system 100, base station 104A can operate as a master eNB (MeNB) or a master gNB (MgNB), and base stations 106A or 106B can be implemented as secondary gNBs (SgNBs) or candidate SgNBs (C-SgNBs). UE 102 can communicate with base station 104A and base stations 106A or 106B via the same radio access technology (RAT) (e.g., EUTRA or NR) or via different RATs. If base station 104A is a MeNB and base station 106A is an SgNB, UE 102 can be in EUTRA-NR Direct Connection (EN-DC) with the MeNB and the SgNB. In this scenario, MeNB 104A may or may not configure base station 106B as a C-SgNB to UE 102. When base station 104A is the MeNB for UE 102 and base station 106A is the C-SgNB for UE 102, UE 102 may be in SC with the MeNB. In this scenario, MeNB 104 may or may not configure base station 106B as another C-SgNB to UE 102.

[0058] In some cases, the MeNB, SeNB, or C-SgNB may be implemented as an ng-eNB instead of an eNB. When base station 104A is a master ng-eNB (Mng-eNB) and base station 106A is an SgNB, UE 102 may be in Next Generation (NG) EUTRA-NR DC (NGEN-DC) with the Mng-eNB and the SgNB. In this scenario, MeNB 104A may or may not configure base station 106B as a C-SgNB to UE 102. When base station 104A is an Mng-NB for UE 102 and base station 106A is a C-SgNB for UE 102, UE 102 may be in a SC with the Mng-NB. In this scenario, Mng-eNB 104A may or may not configure base station 106B as another C-SgNB to UE 102.

[0059] When base station 104A is a MgNB and base station 106A is an SgNB, UE 102 may be in NR-NRDC (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 to UE 102. When base station 104A is a MgNB for UE 102 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 to UE 102.

[0060] When base station 104A is a MgNB and base station 106A is a secondary ng-eNB (Sng-eNB), UE 102 may 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 to UE 102. When base station 104A is the MgNB for UE 102 and base station 106A is a candidate Sng-eNB (C-Sng-eNB) 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 a C-Sng-eNB to UE 102.

[0061] Figure 1B Another implementation of the wireless communication system 100 is illustrated, in which in addition to the base stations 104A, 106A, 106B, the CN 110 is also connected to the base station 104B. The base station 104B may be similar to the one described above with reference to FIG. Figure 1AThe base station 104A discussed herein may also be similar to the base stations 106A and / or 106B. The base station 104B supports the cell 124B. The cells 124B and 124A may partially overlap, such that the UE 102 may detect or measure signals from both the base station 104B and the base station 104A when in a fixed location. In some implementations, the base stations 104A, 104B, 106A, and / or 106B support Figure 1B The base stations 104A, 104B, 106A, 106B may support immediate handover, conditional handover, immediate SN add / change procedures, and / or conditional SN add / change procedures, such as those discussed above and discussed in further detail below.

[0062] Figure 1C An example distributed implementation of any one or more of the base stations 104A, 104B, 106A, 106B is depicted. In this implementation, the base station 104A, 104B, 106A, or 106B includes a centralized unit (CU) 172 and one or more distributed units (DUs) 174. The CU 172 includes processing hardware, such as one or more general-purpose processors (e.g., CPUs) and computer-readable memory that stores machine-readable instructions that can be executed on the general-purpose processors and / or special-purpose processing units. For example, the CU 172 may include Figure 1A The processing hardware 130 or 140 may include a base station RRC controller (e.g., controller 142) configured to manage or control one or more RRC configurations and / or RRC procedures when a base station (e.g., base station 106A) operates as a SN or a candidate SN (C-SN).

[0063] Each of the DUs 174 also includes processing hardware, which may include one or more general-purpose processors (e.g., CPUs) and computer-readable memory storing machine-readable instructions that are executable on the one or more general-purpose processors and / or special-purpose processing units. For example, the processing hardware may include a medium access control (MAC) controller configured to manage or control one or more MAC operations or procedures (e.g., random access procedures) and a radio link control (RLC) controller configured to manage or control one or more RLC operations or procedures when the base station (e.g., base station 106A) operates as an MN, SN, or C-SN. The processing hardware may also include a physical layer controller configured to manage or control one or more physical layer operations or procedures.

[0064] FIG2 illustrates, in simplified form, an example radio protocol stack 200 by which a UE 102 can communicate with an eNB / ng-eNB or gNB (e.g., one or more of base stations 104A, 104B, 106A, 106B). In the example stack 200, the EUTRA physical layer (PHY) 202A provides transport channels to the EUTRA MAC sublayer 204A, which in turn provides logical channels to the EUTRA RLC sublayer 206A. The EUTRA RLC sublayer 206A, in turn, provides RLC channels to the EUTRA PDCP sublayer 208 and, in some cases, to the NR PDCP sublayer 210. Similarly, the NR PHY 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 RLC channels to the NR PDCP sublayer 210. In some implementations, the UE 102 supports both EUTRA and NR stacks as shown in FIG2 to support handover between EUTRA base stations and NR base stations and / or to support DC over the EUTRA and NR interfaces. In addition, as illustrated in FIG2 , the UE 102 may support layering of the NR PDCP sublayer 210 on the EUTRA RLC sublayer 206A.

[0065] 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 that the difference between SDUs and PDUs is relevant.

[0066] For example, on the control plane, the EUTRA PDCP sublayer 208 and the NR PDCP sublayer 210 may provide SRBs to exchange RRC messages. On the user plane, the EUTRA PDCP sublayer 208 and the NR PDCP sublayer 210 may provide DRBs to support data exchange.

[0067] In a scenario where the UE 102 operates in EUTRA / NR DC (EN-DC), where the base station 104A operates as a MeNB and the base station 106A operates as an SgNB, the wireless communication system 100 can provide the UE 102 with either a MN-terminated bearer using the EUTRA PDCP sublayer 208 or a MN-terminated bearer using the NR PDCP sublayer 210. In various scenarios, the wireless communication system 100 can also provide the UE 102 with an SN-terminated bearer using only the NR PDCP sublayer 210. The MN-terminated bearer can be an MCG bearer or a split bearer. The SN-terminated bearer can be an SCG bearer or a split bearer. The MN-terminated bearer can be an SRB (e.g., SRB1 or SRB2) or a DRB. The SN-terminated bearer can be an SRB or a DRB.

[0068] 3 through 11 illustrate message sequences between the UE 102 and various base stations of the RAN (including base stations 104A, 106A, and / or 106B) for various scenarios and implementations related to conditional configuration management.

[0069] Specifically, Figures 3 to 5 correspond to a conditional handover (CHO) scenario in which the wireless communication system 100 uses a configuration identifier to track candidate cell configurations, Figures 6 to 8 correspond to a conditional SN addition / change scenario in which the wireless communication system 100 uses a configuration identifier to track candidate SN configurations, and Figure 9 (i.e., 9A to 9C) corresponds to a scenario in which the wireless communication system 100 uses a configuration identifier to release a conditional configuration (for CHO or SN addition / change) at the UE 102.

[0070] Figures 10 and 11 correspond to alternative implementations in which the RAN of the wireless communication system 100 provides the full set of conditional handover configurations to the UE 102 to avoid any uncertainty (at the UE 102) about the current full configuration list, where Figure 10 corresponds to a CHO scenario and Figure 11 corresponds to a conditional SN addition or change scenario.

[0071] First reference Figures 3A to 3C , shows a conditional switching scenario where the configuration identifier used to manage / track the configuration is a transaction ID.

[0072] exist Figure 3A In the conditional handover scenario 300A, base station 104A operates as the MN of UE 102, and base station 106A operates as the candidate MN (C-MN) of UE 102. Figures 3A to 3Cand other figures) refer to the source base station as MN, and the candidate or target base station as candidate or target MN, it being understood that in other scenarios, base station 104A may alternatively be a base station operating in the SC with UE 102, and base station 106A may alternatively be a candidate base station which itself will operate in the SC with UE 102 if a handover to base station 106A should occur.

[0073] Initially, UE 102 communicates 302A data (e.g., uplink (UL) data PDUs and / or downlink (DL) data PDUs) with MN 104A. MN 104A then determines 310A at some point to configure a conditional handover to a candidate cell (e.g., a candidate PCell) for UE 102, for example, blindly or in response to detecting a suitable event. For example, determination 310A may occur in response to MN 104A receiving one or more measurement results from UE 102 that are above (or below) one or more predetermined thresholds or calculating a filtering result (based on the measurement results) that is above (or below) a predetermined threshold. In another example, the suitable event may be UE 102 moving toward C-MN 106A. In yet another example, the suitable event may be one or more measurement results generated / obtained by MN 104A based on measurements of signals received from UE 102 that are above (or below) one or more predetermined thresholds.

[0074] After determining 310A to configure conditional handover, MN 104A assigns 320A a specific transaction identifier or identification (transaction ID) to the conditional handover, or equivalently, assigns 320A to the configuration associated with the conditional handover (in a CHO command). In the depicted scenario, the assigned identifier is "transaction ID 1." As described above, as used herein (and unless a more specific meaning is clear from the context of its use), "assigning" a configuration identifier can refer to the act of initially selecting an identifier (i.e., for an entirely new configuration), or to the subsequent selection of a previously selected / used identifier (i.e., when attempting to modify an existing configuration). Thus, depending on the scenario, MN 104A may select transaction ID 1 because MN 104A intends to introduce a new configuration and transaction ID 1 has not yet been used for any conditional configuration currently assigned to UE 102, or because MN 104A intends to modify an existing configuration to which MN 104A (or possibly another network node) previously assigned identifier transaction ID 1.

[0075] In response to determining 310A, and after allocating 320A transaction ID 1, MN 104A sends 326A a handover request message including transaction ID 1 to C-MN 106A. The transaction ID may be an integer or other value generally used to identify a particular RRC procedure (transaction), for example, as specified in 3GPP TS 36.331 or 38.331. In response to the handover request message, C-MN 106A includes the allocated transaction ID (transaction ID 1) in a CHO command and includes the CHO command in a handover request confirm message for UE 102. C-MN 106A sends 330A a handover request confirm message to MN 104A in response to the handover request message. The CHO command includes one or more configurations for a first candidate cell (which may be referred to as a candidate PCell (C-PCell)) of C-MN 106A. The configurations include information that enables UE 102 to communicate with the first candidate cell if corresponding conditions are met. The CHO command including the candidate cell configuration and transaction ID 1 is sent 330A to MN 104A. Figure 3A It is shown as "CHO command 1".

[0076] MN 104A sends 334A CHO Command 1 (including Transaction ID 1) to UE 102. UE 102 identifies the Transaction ID and, based on its value (Transaction ID 1), adds or modifies 340A a configuration. That is, UE 102 adds 340A CHO Command 1 as a new CHO command or uses CHO Command 1 to modify 340A an existing CHO command already stored at UE 102 (i.e., modifies at least a portion of the configuration in the CHO command already stored in the memory of UE 102). In detail, with the received CHO Command 1 334A, UE 102 identifies the Transaction ID to add a CHO command or to modify a CHO command stored in UE 102. If UE 102 determines that Transaction ID 1 has been previously used for a stored CHO command (i.e., Transaction ID 1 is associated with the stored CHO command), UE 102 modifies the stored CHO command with the configuration of CHO Command 1. In some cases, UE 102 replaces the stored CHO command with CHO command 1. In other cases, UE 102 replaces only a subset of the configuration parameters in the stored CHO command with one or more configuration parameters in CHO command 1. As used herein, "modifying" a configuration may refer to replacing the entire pre-existing configuration or only replacing a subset of the pre-existing configuration. If UE 102 instead determines that transaction ID 1 is a new transaction ID, UE 102 stores CHO command 1 as the new CHO command.

[0077] In some scenarios, 310A to 340A may be repeated for additional conditional handovers and CHO commands. For example, MN 104A may later assign "transaction ID 2" to "CHO command 2" received by UE 102 (e.g., after another transmission similar to transmission 334A). UE 102 may then store CHO command 2 as a new configuration (if transaction ID 2 is different from transaction ID 1 and is not used for any other CHO command already stored at UE 102 and not released), or use CHO command 2 to replace part or all of a pre-existing (i.e., already stored and not released) CHO command that also includes transaction ID 2 (or is otherwise associated with transaction ID 2).

[0078] In one implementation and scenario, after UE 102 adds 340A CHO command 1 or modifies 340A the CHO command using CHO command 1, and before UE 102 releases the corresponding configuration, UE 102 determines 360A that conditions for handover to a specific candidate cell of C-MN 106A are met, and in response, initiates 366A a random access procedure on the specific candidate cell. In the depicted scenario, the specific candidate cell is the cell for which MN 104A determines 310A to configure conditional handover.

[0079] UE 102 then performs 370A a random access procedure with C-MN 106A via the candidate cell according to the configuration of CHO command 1 (e.g., random access preamble, etc.), and sends 376A a CHO complete message including transaction ID 1 to C-MN 106A via the candidate cell during or after the random access procedure. If UE 102 instead determines 360A that a different candidate cell is satisfied, UE 102 performs 370A a random access procedure with C-MN 106A (or possibly another base station) via the other candidate cell according to the corresponding CHO command / configuration. Operations 360A, 366A, and 370A and sending 376A are performed in Figure 3A are collectively referred to as process 380A.

[0080] In some implementations, MN 104A may indicate to C-MN 106A in a handover request message that base station 106A is being requested for the purpose of conditional handover of UE 102 (ie, requested to serve as the C-MN for UE 102).

[0081] In one implementation, a CHO command (e.g., CHO command 1) includes information specifying a condition for conditional handover (i.e., a conditional configuration for the condition). MN 104A may generate an RRC container message including the CHO command (without a separate conditional configuration) and send the RRC container message to UE 102 at event 334A. Alternatively, the handover request confirm message and the CHO command may not include a conditional configuration, and MN 104A may generate / configure the conditional configuration. In this implementation, MN 104A generates an RRC container message including the CHO command and the conditional configuration and sends the RRC container message to UE 102 at event 334A. In some implementations, UE 102 sends an RRC container response message to MN 104A in response to the RRC container message.

[0082] In some implementations, the CHO command may include one or more cell group configuration (CellGroupConfig) information elements (IEs) that configure one or more candidate cells. For example, the CHO command may include a CellGroupConfig that configures a specific candidate cell. In another example, the CHO command may include one or more CellGroupConfig IEs that configure one or more candidate cells. For example, the CellGroupConfig IE may be defined in 3GPP TS 38.331. In other implementations, the CHO command is an RRCReconfiguration message, and the CHO completion message is an RRCReconfigurationComplete message, as defined in 3GPP TS 38.331.

[0083] In some implementations, the CHO command may include one or more RRCConnectionReconfiguration-r8-IEs that configure one or more candidate cells. For example, the CHO command may include an RRCConnectionReconfiguration-r8-IE that configures a specific candidate cell. In another example, the CHO command may include more than one RRCConnectionReconfiguration-r8-IE that configures one or more candidate cells. For example, the RRCConnectionReconfiguration-r8-IE may be defined in 3GPP TS 36.331. In other implementations, the CHO command is an RRCConnectionReconfiguration message, as defined in 3GPP TS 36.331. In other implementations, the CHO command may include one or more IE groups that configure one or more candidate cells. For example, each group may include a MobilityControlInfo IE, a RadioResourceConfigDedicated IE, and a SecurityConfigHO IE.

[0084] exist Figure 3B In the conditional handover scenario 300B, base station 104A again operates as the MN of UE 102, and base station 106A again operates as the C-MN of UE 102. Initially, UE 102 communicates 302B data (e.g., UL data PDUs and / or DL data PDUs) with MN 104A. MN 104A then, at some point, for example, blindly or in response to detecting a suitable event (as described above with reference to FIG. 3 ), switches to the C-MN. Figure 3A As discussed above, the UE 102 determines 310B to configure a conditional handover to a candidate cell (eg, a candidate PCell) for the UE 102.

[0085] In response to the determination 310B, the MN 104A sends 326B a handover request message to the C-MN 106A. Figure 3A In the MN 104A, the transaction ID is assigned 320A. Figure 3B In the example, C-MN 106A allocates 320B a transaction ID. Allocation 320B may be otherwise similar to allocation 320A, and the allocated transaction ID may be, for example, the one described above with reference to Figure 3A The ID of any transaction in question.

[0086] In response to the Handover Request message, and after assigning 320B the identifier "Transaction ID 1", C-MN 106A includes Transaction ID 1 in a CHO command ("CHO Command 1") and includes the CHO command in a Handover Request Acknowledge message for UE 102. C-MN 106A sends 330B a Handover Request Acknowledge message to MN 104A in response to the Handover Request message. CHO Command 1 may be similar to the one described above with reference to Figure 3A CHO command discussed1.

[0087] MN 104A sends 334B CHO command 1 (including transaction ID 1) to UE 102. UE 102 identifies the transaction ID and, based on its value (transaction ID 1), adds or modifies 340B the configuration, e.g., as described above with reference to Figure 3A In some scenarios, 310B to 340B may be repeated for additional conditional switches and CHO commands, as discussed above.

[0088] In one implementation and scenario, after the UE 102 adds 340B CHO command 1 or modifies 340B CHO command using CHO command 1, and before the UE 102 releases the corresponding configuration, in process 380B, the UE 102 determines that the conditions for handover to the specific candidate cell of the C-MN 106A are met, and in response, initializes and performs a random access procedure on the specific candidate cell. For example, process 380B may be similar to Figure 3A Process 380A.

[0089] As mentioned above Figure 3A As discussed, in one implementation, a CHO command (e.g., CHO command 1) includes information specifying a condition for conditional handover (i.e., a conditional configuration for the condition). MN 104A may generate an RRC container message including the CHO command and, at event 334B, send the CHO command to UE 102. Alternatively, the handover request confirmation message and the CHO command may not include the conditional configuration, and MN 104A may generate / configure the conditional configuration. In this implementation, MN 104A generates an RRC container message including the CHO command and the conditional configuration and, at event 334B, sends the RRC container message to UE 102. In some implementations, UE 102 sends an RRC container response message to MN 104A in response to the RRC container message.

[0090] exist Figure 3CIn the conditional handover scenario 300C, the base station 104A again operates as the MN of the UE 102. Initially, the UE 102 communicates 302C data (e.g., UL data PDUs and / or DL data PDUs) with the MN 104A. The MN 104A then, at some point, for example, blindly or in response to detecting a suitable event (as described above with reference to FIG. 3 ), switches to the MN 104A. Figure 3A (as discussed) determines 310C to configure conditional handover to a candidate cell (e.g., candidate PCell) of the UE 102.

[0091] In scenario 300C, and unlike scenarios 300A and 300B, the candidate cell is another cell of the same MN 104A, and inter-base station messaging may not be required for conditional handover. Therefore, after MN 104A assigns 320C a configuration identifier "Transaction ID1" (e.g., in a format similar to Figure 3A After the allocation 320A of the MN 104A, the MN 104A generates a CHO command ("CHO Command 1") including the transaction ID 1 and sends 334C the CHO command to the UE 102. The CHO Command 1 and the transaction ID 1 may be similar to those described above with reference to FIG. Figure 3A The CHO command 1 and transaction ID 1 are discussed.

[0092] After receiving the CHO command 1, the UE 102 identifies the transaction ID and, based on its value (transaction ID 1), adds or modifies 340C the configuration, e.g., as described above with reference to Figure 3A In some scenarios, 310C to 340C may be repeated for additional conditional switches and CHO commands, as discussed above.

[0093] In one implementation and scenario, after UE 102 adds 340C CHO command 1 or modifies 340C CHO command using CHO command 1, and before UE 102 releases the corresponding configuration, UE 102 determines 361C that conditions for handover to a specific candidate cell of MN 104A are met, and in response, initiates 367C a random access procedure on the specific candidate cell. In the depicted scenario, the specific candidate cell is the cell for which MN 104A determines 310C to configure conditional handover.

[0094] Then, UE 102 performs 371C a random access procedure with MN 104A via the candidate cell according to the configuration of CHO command 1 (e.g., random access preamble, etc.), and sends 377C a CHO complete message including transaction ID 1 to MN 104A via the candidate cell during or after the random access procedure. If UE 102 instead determines 361C that the conditions of a different candidate cell (of MN 104A or another base station) are met, UE 102 performs 371C a random access procedure with MN 104A or another base station via the other candidate cell according to the corresponding CHO command / configuration. Operations 361C, 367C, and 371C and sending 377C are performed in Figure 3C are collectively referred to as Process 381C.

[0095] As mentioned above Figure 3A As discussed, in one implementation, a CHO command (e.g., CHO command 1) includes information specifying a condition for conditional handover (i.e., a conditional configuration for the condition). MN 104A may generate an RRC container message including the CHO command and, at event 334C, send the CHO command to UE 102. In this implementation, MN 104A generates an RRC container message including the CHO command and the conditional configuration and, at event 334C, sends the RRC container message to UE 102. In some implementations, UE 102 sends an RRC container response message to MN 104A in response to the RRC container message.

[0096] Next reference Figure 4A and 4B , shows a conditional handover scenario, where the configuration identifier used for management / tracking configuration is the cell ID.

[0097] exist Figure 4A In the conditional handover scenario 400A, base station 104A operates as the MN of UE 102, and base station 106A operates as the C-MN of UE 102. Initially, UE 102 communicates 402A data (e.g., UL data PDUs and / or DL data PDUs) with MN 104A. MN 104A then switches to the MN at some point, e.g., blindly or in response to detecting a suitable event (as described above with reference to FIG. 4 ). Figure 3A As discussed above, the system determines 410A to configure a conditional handover to a candidate cell (eg, candidate PCell) for the UE 102.

[0098] After determining 410A, the MN 104A assigns 420A a cell ID to the conditional configuration. The assignment 420A may be similar to Figure 3A420A, except that the MN 104A assigns a cell ID instead of a transaction ID. In the example scenario 400A, the MN 104A assigns 420A an identifier "Cell ID1" to the conditional handover configuration, where Cell ID1 identifies a candidate cell (e.g., a C-PCell) for which the MN 104A is configuring conditional handover. In various implementations, the cell ID may be a physical cell ID (PCI, e.g., as specified in 3GPP TS 36.323 or 38.423), a cell global ID (CGI), or another suitable identifier for a particular cell in the wireless communication system 100. In some implementations, as discussed further below, the MN 104A does not assign 420A Cell ID1, but instead includes a cell identifier from which Cell ID1 may be later derived (e.g., by the C-MN 106A).

[0099] After allocating 420A cell ID1 (or including a corresponding cell identifier from which cell ID1 can be derived), MN 104A sends 426A a handover request message including cell ID1 (or a corresponding cell identifier) to C-MN 106A. In response to the handover request message, C-MN 106A includes cell ID1 in a CHO command ("CHO Command 1"), includes the CHO command in a handover request confirm message, and sends 430A the handover request confirm message to MN 104A. In some implementations, cell ID1 is a specific PCI value that C-MN 106A derives from the CGI value included in the handover request message by MN 104A. In this implementation, the "allocation" at event 420A can be considered a combination of (1) determining the CGI at MN 104A and (2) deriving the PCI from the CGI at C-MN 106A. In other implementations, the same cell identifier (e.g., CGI or PCI) is included in both the handover request message and the handover request confirm message. For example, CHO command 1 may be similar to the one described above with reference to FIG. 1 , except that the cell ID is used as the configuration identifier. Figure 3A The CHO command 1 discussed above and the handover request and handover request confirmation messages may be similar to those in the reference Figure 3A The Handover Request and Handover Request Confirmation messages are discussed.

[0100] MN 104A sends 434A CHO command 1 (including cell ID 1) to UE 102. UE 102 identifies the cell ID and based on its value (cell ID 1), adds or modifies 440A the configuration, e.g., as described above with reference to Figure 3A as discussed, but based on cell ID instead of transaction ID.

[0101] In some scenarios, 410A to 440A may be repeated for additional conditional handovers and CHO commands. For example, MN 104A may later assign "cell ID 2" to "CHO command 2" received by UE 102 (e.g., after another transmission similar to transmission 434A). UE 102 may then store CHO command 2 as a new configuration (if cell ID 2 is different from cell ID 1 and is not used in any other CHO command already stored at UE 102 and not released), or use CHO command 2 to replace part or all of a pre-existing (i.e., already stored and not released) CHO command that also includes cell ID 2 (or is otherwise associated with cell ID 2).

[0102] In one implementation and scenario, after the UE 102 adds 440A a CHO command 1 or modifies 440A the CHO command using the CHO command 1, and before the UE 102 releases the corresponding configuration, the UE 102 determines 460A that conditions for handover to a specific candidate cell of the C-MN 106A are met, and in response, initiates 466A a random access procedure on the specific candidate cell. In the depicted scenario, the specific candidate cell is the cell for which the MN 104A determines 410A to configure conditional handover.

[0103] The UE 102 then performs 470A a random access procedure with the C-MN 106A via the candidate cell according to the configuration of the CHO command 1 (e.g., random access preamble, etc.), and sends 476A a CHO complete message to the C-MN 106A via the candidate cell during or after the random access procedure. If the UE 102 instead determines 460A that it meets the conditions of a different candidate cell, the UE 102 performs 470A a random access procedure with the C-MN 106A (or possibly another base station) via the other candidate cell according to the corresponding CHO command / configuration. Operations 460A, 466A, and 470A and sending 476A are performed in Figure 4A are collectively referred to as Process 482A.

[0104] As mentioned above Figure 3AAs discussed, in one implementation, a CHO command (e.g., CHO command 1) includes information specifying a condition for conditional handover (i.e., a conditional configuration for the condition). MN 104A may generate an RRC container message including the CHO command and, at event 434A, send the CHO command to UE 102. Alternatively, the handover request confirm message and the CHO command may not include the conditional configuration, and MN 104A may generate / configure the conditional configuration. In this implementation, MN 104A generates an RRC container message including the CHO command and the conditional configuration and, at event 434A, sends the RRC container message to UE 102. In some implementations, UE 102 sends an RRC container response message to MN 104A in response to the RRC container message.

[0105] exist Figure 4B In the conditional handover scenario 400B, the base station 104A again operates as the MN of the UE 102. Initially, the UE 102 communicates 402B data (e.g., UL data PDUs and / or DL data PDUs) with the MN 104A. The MN 104A then, at some point, for example, blindly or in response to detecting a suitable event (as described above with reference to FIG. 4B ), switches to the MN 104A. Figure 3A As discussed above, the UE 102 determines 410B to configure a conditional handover to a candidate cell (eg, a candidate PCell) for the UE 102.

[0106] In scenario 400B, and unlike scenario 400A, the candidate cell is another cell of the same MN 104A, and inter-base station messaging may not be required for conditional handover. Therefore, after MN 104A assigns 420B a configuration identifier "Cell ID1" (e.g., in a format similar to Figure 4A After the allocation 420A of the cell ID, the MN 104A generates a CHO command ("CHO command 1") including the cell ID 1 and sends 434B the CHO command to the UE 102. The CHO command 1 may be similar to the CHO command described above with reference to FIG. Figure 3A The CHO command 1 discussed above and the cell ID 1 can be similar to the Figure 4A The cell ID 1 in question (eg, PCI derived from CGI).

[0107] After receiving CHO command 1, UE 102 identifies the cell ID and adds or modifies 440B configuration based on its value (cell ID 1), e.g., as described above with reference to Figure 3A In some scenarios, 410B to 440B may be repeated for additional conditional switches and CHO commands, as discussed above.

[0108] In one implementation and scenario, after UE 102 adds 440B CHO command 1 or modifies 440B the CHO command using CHO command 1, and before UE 102 releases the corresponding configuration, UE 102 determines 461B that conditions for handover to a specific candidate cell of MN 104A are met, and in response, initiates 467B a random access procedure on the specific candidate cell. In the depicted scenario, the specific candidate cell is the cell for which MN 104A determines 410B to configure conditional handover.

[0109] Then, UE 102 performs 471B a random access procedure with MN 104A via the candidate cell according to the configuration of CHO command 1 (e.g., random access preamble, etc.), and sends 477B a CHO complete message to MN 104A via the candidate cell during or after the random access procedure. If UE 102 instead determines 461B that the conditions of a different candidate cell (of MN 104A or another base station) are met, UE 102 performs 471B a random access procedure with MN 104A or another base station via the other candidate cell according to the corresponding CHO command / configuration. Operations 461B, 467B, and 471B and sending 477B are performed in Figure 4B are collectively referred to as Process 483B.

[0110] As mentioned above Figure 3A As discussed, in one implementation, a CHO command (e.g., CHO command 1) includes information specifying a condition for conditional handover (i.e., a conditional configuration for the condition). MN 104A may generate an RRC container message including the CHO command and, at event 434B, send the CHO command to UE 102. In this implementation, MN 104A generates an RRC container message including the CHO command and the conditional configuration and, at event 434B, sends the RRC container message to UE 102. In some implementations, UE 102 sends an RRC container response message to MN 104A in response to the RRC container message.

[0111] Next reference Figures 5A to 5D , shows a conditional handover scenario, where the configuration identifier used to manage / track the configuration is a dedicated configuration identifier (ie, an information element dedicated to identifying a conditional handover configuration).

[0112] exist Figure 5A In the conditional handover scenario 500A, base station 104A operates as the MN of UE 102, and base station 106A operates as the C-MN of UE 102. Initially, UE 102 communicates 502A data (e.g., UL data PDUs and / or DL data PDUs) with MN 104A. MN 104A then switches to the MN at some point, e.g., blindly or in response to detecting a suitable event (as described above with reference to FIG. 5 ). Figure 3A As discussed above, the UE 102 determines 510A to configure a conditional handover to a candidate cell (eg, a candidate PCell) for the UE 102.

[0113] After determining 510A, the MN 104A assigns 520A a configuration ID to the conditional configuration. The assignment 520A may be similar to the assignment 510A, except that the MN 104A assigns a dedicated configuration identifier instead of a transaction ID or cell ID. Figure 3A Assignment 320A or Figure 4A In the example scenario 500A, the MN 104A assigns 520A the identifier "Configuration ID1" to the conditional handover configuration. For example, a dedicated configuration identifier may be an integer or other value used to identify a specific CHO command.

[0114] After allocating 520A configuration ID 1, MN 104A sends 526A a handover request message to C-MN 106A including configuration ID 1. In response to the handover request message, C-MN 106A includes configuration ID 1 in a CHO command ("CHO Command 1"), includes the CHO command in a handover request confirm message, and sends 530A the handover request confirm message to MN 104A. CHO Command 1 may be similar to the one described above with reference to FIG. 5 , except that a dedicated configuration identifier is used. Figure 3A The CHO command 1 discussed above and the handover request and handover request confirmation messages may be similar to those in the reference Figure 3A The Handover Request and Handover Request Confirmation messages are discussed.

[0115] MN 104A sends 534A CHO command 1 (including configuration ID 1) to UE 102. UE 102 identifies the configuration ID and based on its value (configuration ID 1), adds or modifies 540A the configuration, e.g., as described above with reference to Figure 3A as discussed, but based on dedicated configuration identifiers instead of transaction IDs.

[0116] In some scenarios, 510A to 540A may be repeated for additional conditional handovers and CHO commands. For example, MN 104A may later assign "Configuration ID 2" to "CHO Command 2" received by UE 102 (e.g., after another transmission similar to transmission 534A). UE 102 may then store CHO Command 2 as a new configuration (if Configuration ID 2 is different from Configuration ID 1 and is not used in any other CHO command already stored at UE 102 and not yet released), or use CHO Command 2 to replace part or all of a pre-existing (i.e., already stored and not released) CHO command that also includes (or is otherwise associated with) Configuration ID 2.

[0117] In one implementation and scenario, after the UE 102 adds 540A a CHO command 1 or modifies 540A a CHO command using a CHO command 1, and before the UE 102 releases the corresponding configuration, in process 582A, the UE 102 determines that the conditions for handover to the candidate cell of the C-MN 106A are met, and in response, initiates and performs a random access procedure on the candidate cell. For example, process 582A may be similar to Figure 4A Process 482A.

[0118] As mentioned above Figure 3A As discussed, in one implementation, a CHO command (e.g., CHO command 1) includes information specifying a condition for conditional handover (i.e., a conditional configuration for the condition). MN 104A may generate an RRC container message including the CHO command and send the CHO command to UE 102 at event 534A. Alternatively, the handover request confirm message and the CHO command may not include the conditional configuration, and MN 104A may generate / configure the conditional configuration. In this implementation, MN 104A generates an RRC container message including the CHO command and the conditional configuration and sends the RRC container message to UE 102 at event 534A. In some implementations, UE 102 sends an RRC container response message to MN 104A in response to the RRC container message.

[0119] exist Figure 5B In the conditional handover scenario 500B, the base station 104A again operates as the MN of the UE 102, and the base station 106A again operates as the C-MN of the UE 102. Initially, the UE 102 communicates 502B data (e.g., UL data PDUs and / or DL data PDUs) with the MN 104A. Then, at some point, for example, blindly or in response to detecting a suitable event (as described above with reference to FIG. 5 ), the MN 104A switches to the C-MN. Figure 3A As discussed above, the UE 102 determines 510B to configure a conditional handover to a candidate cell (eg, a candidate PCell) for the UE 102.

[0120] In response to the determination 510B, the MN 104A sends 526B a handover request message to the C-MN 106A. Figure 5A In the example, after receiving the handover request message, MN 104A allocates 520A a dedicated configuration identifier. Figure 5B In the example, C-MN 106A allocates 520B a dedicated configuration identifier. Allocation 520B may be otherwise similar to allocation 520A, and the allocated configuration identifier may be, for example, the one described above with reference to Figure 5A Identifier of any configuration in question.

[0121] In response to the Handover Request message, and after assigning 520B the identifier "Configuration ID 1", the C-MN 106A includes the Configuration ID 1 in a CHO command ("CHO Command 1") and includes the CHO command in a Handover Request Acknowledge message for the UE 102. The C-MN 106A sends 530B a Handover Request Acknowledge message to the MN 104A in response to the Handover Request message. For example, the CHO Command 1 may be similar to the one described above with reference to FIG. 5 , except that a dedicated configuration identifier is used. Figure 3A The CHO command 1 discussed above and the handover request and handover request confirmation messages may be similar to those in the reference Figure 3B The Handover Request and Handover Request Confirmation messages are discussed.

[0122] MN 104A sends 534B CHO command 1 (including configuration ID 1) to UE 102. UE 102 identifies the configuration identifier and based on its value (configuration ID 1), adds or modifies 540B the configuration, e.g., as described above with reference to Figure 3A In some scenarios, 510B to 540B may be repeated for additional conditional switches and CHO commands, as discussed above.

[0123] In one implementation and scenario, after the UE 102 adds 540B CHO command 1 or modifies 540B CHO command using CHO command 1, and before the UE 102 releases the corresponding configuration, in process 582B, the UE 102 determines that the conditions for handover to the specific candidate cell of the C-MN 106A are met, and in response, initializes and performs a random access procedure on the specific candidate cell. For example, process 582B may be similar to Figure 4A Process 482A.

[0124] As mentioned above Figure 3A As discussed, in one implementation, a CHO command (e.g., CHO command 1) includes information specifying a condition for conditional handover (i.e., a conditional configuration for the condition). MN 104A may generate an RRC container message including the CHO command and, at event 534B, send the CHO command to UE 102. Alternatively, the handover request confirmation message and the CHO command may not include a conditional configuration, and MN 104A may generate / configure the conditional configuration. In this implementation, MN 104A generates an RRC container message including the CHO command and the conditional configuration and, at event 534B, sends the RRC container message to UE 102. In some implementations, UE 102 sends an RRC container response message to MN 104A in response to the RRC container message.

[0125] exist Figure 5CIn the conditional handover scenario 500C, the base station 104A again operates as the MN of the UE 102. Initially, the UE 102 communicates 502C data (e.g., UL data PDUs and / or DL data PDUs) with the MN 104A. The MN 104A then, at some point, for example, blindly or in response to detecting a suitable event (as described above with reference to FIG. 5 ), switches to the MN 104A. Figure 3A As discussed above, the UE 102 determines 510C to configure a conditional handover to a candidate cell (eg, a candidate PCell) for the UE 102.

[0126] In scenario 500C, and unlike scenarios 500A and 500B, the candidate cell is another cell of the same MN 104A, and inter-base station messaging may not be required for conditional handover. Therefore, the MN 104A assigns 520C a configuration identifier "Configuration ID1" (e.g., in a format similar to Figure 5A After the MN 104A generates a CHO command ("CHO Command 1") including the configuration ID1, and sends 334C the CHO command to the UE 102. The CHO Command 1 and the configuration ID1 may be similar to those described above with reference to FIG. Figure 5A Discuss CHO command 1 and configuration ID 1.

[0127] After receiving the CHO command 1, the UE 102 identifies the configuration identifier and, based on its value (Configuration ID1), adds or modifies 540C the configuration, e.g., as described above with reference to Figure 3A In some scenarios, 510C to 540C may be repeated for additional conditional switches and CHO commands, as discussed above.

[0128] In one implementation and scenario, after UE 102 adds 540C CHO command 1 or modifies 540C CHO command using CHO command 1, and before UE 102 releases the corresponding configuration, in process 583C, UE 102 determines that the conditions for handover to the candidate cell of MN 104A are met, and initializes and performs a random access procedure on the candidate cell. For example, process 583C may be similar to Figure 4B Process 483B.

[0129] exist Figure 5D In the conditional handover scenario 500D, the base station 104A again operates as the MN of the UE 102. Initially, the UE 102 communicates 502D data (e.g., UL data PDUs and / or DL data PDUs) with the MN 104A. The MN 104A then, at some point, for example, blindly or in response to detecting a suitable event (as described above with reference to FIG. 5 ), switches to the MN 104A. Figure 3A As discussed above, the system determines 510D to configure or reconfigure a conditional handover to a candidate cell (eg, candidate PCell) of the UE 102.

[0130] In response to the determination 510D, the MN 104A sends 526D a handover request message including a cell ID corresponding to the determination to the C-MN 106A. In response to the handover request message, the C-MN 106A includes a CHO command ("CHO Command 1") and cell ID 1 in a handover request confirm message and sends 530D the handover request confirm message to the MN 104A. For example, the CHO Command 1 may be similar to the one described above with reference to FIG. 5 , except that the dedicated transaction identifier is not included. Figure 3A The CHO command 1 discussed above and the handover request and handover request confirmation messages may be similar to those in the reference Figure 3A The Handover Request and Handover Request Confirmation messages are discussed.

[0131] MN 104A selects 532D a dedicated configuration identifier (Configuration ID 1) for the CHO command. "Selecting" Configuration ID 1 may be assigning a new Configuration ID, or selecting an existing Configuration ID (detailed example implementations are described below). MN 104A sends 534D the CHO command (e.g., CHO Command 1) and Configuration ID 1 to UE 102. UE 102 adds or modifies (e.g., replaces) 540D the CHO command, e.g., as described above with reference to Figure 3A discussed.

[0132] In some scenarios, 510D to 540D may be repeated for additional conditional handovers and CHO commands. For example, MN 104A may later assign "Configuration ID 2" to "CHO Command 2" received by UE 102 (e.g., after another transmission similar to transmission 534D). UE 102 may then store CHO Command 2 as a new configuration (if Configuration ID 2 is different from Configuration ID 1 and is not used for any other CHO command already stored at UE 102 and not yet released), or use CHO Command 2 to replace part or all of a pre-existing (i.e., already stored and not released) CHO command that also includes (or is otherwise associated with) Configuration ID 2.

[0133] In one implementation and scenario, after the UE 102 adds 540D CHO command 1 or modifies (or replaces) 540D CHO command 1 with CHO command 1, and before the UE 102 releases the corresponding configuration, in process 582D, the UE 102 determines that the conditions for handover to the candidate cell of the C-MN 106A are met, and in response, initializes and performs a random access procedure on the candidate cell. For example, process 582D may be similar to Figure 4A Process 482A.

[0134] In some implementations, the MN 104A has (i.e., stores) a table (e.g., Table 1-1) for selecting a configuration ID for a CHO command for the UE 102. The table includes entries for a cell ID, a configuration ID, and a configuration state (e.g., whether the cell has been configured for the UE 102 for CHO). In some implementations, the MN 104A can be configured by an operations and maintenance (O&M) node using the table. The O&M node can reconfigure (e.g., update) the table. For example, the O&M node can reconfigure the table by adding a new entry including a new cell ID with a configuration state of "unconfigured" and a new configuration ID. In other implementations, the MN 104A can be configured by default or manually using the table.

[0135] Table 1-1

[0136]

[0137] Table 1-2

[0138]

[0139]

[0140] In one example, the MN 104A may initialize the table to Table 1-2 when or before the MN 104A receives a CHO command. If the cell ID of the candidate cell 510D is cell ID 1, the MN 104A sets the configuration state of cell ID 1 to "configured" in response to determining 510D or receiving 530D a CHO command (e.g., CHO command 1), as shown in Table 1-3. The MN 104A uses configuration ID 1 for CHO command 1 (because CHO command 1 is for cell ID 1) according to the table, and the MN 104A in turn sends configuration ID 1 and CHO command 1 at event 534D. That is, if the MN 104A determines to configure a conditional handover to a cell identified by a specific cell ID, or if the MN 104A receives a CHO command for a specific cell ID, the MN 104A uses the specific cell ID (e.g., cell ID 1) as an index to look up the table.

[0141] Table 1-3

[0142]

[0143] In another example, before MN 104A receives CHO command 530D, MN 104A has / stores a table as Table 1-3. If the cell ID of candidate cell 510D is cell ID1, MN 104A may or may not set the configuration state of cell ID1 to "configured" in response to determining 510D or receiving 530D a CHO command (e.g., CHO command 1), as shown in Table 1-3. MN 104A uses configuration ID1 for CHO command 1 (because CHO command 1 is for cell ID1) according to the table and sends configuration ID1 and CHO command 1 at event 534D. If the cell ID of candidate cell 510D is cell ID2, MN 104A sets the configuration state of cell ID2 to "configured" in response to determining 510D or receiving 530D a CHO command (e.g., CHO command 2), as shown in Table 1-4. MN 104A uses configuration ID 2 for CHO command 2 (because CHO command 2 is for cell ID 2) according to the table, and sends configuration ID 2 and CHO command 2 at event 534D. That is, if MN 104A determines to configure a conditional handover to a specific cell ID, or if MN 104A receives a CHO command for a specific cell ID, MN 104A uses the specific cell ID (e.g., cell ID 1) as an index to look up the table.

[0144] Table 1-4

[0145]

[0146] If MN 104A determines to release the CHO command for a cell ID with a configuration state of "Configured," MN 104A searches the table using the cell ID as an index to find the configuration ID for the cell ID and may send a CHO release configuration including the configuration ID. UE 102 releases the CHO command based on the configuration ID in the CHO release configuration. For example, MN 104A may determine to release the CHO command for cell ID 1. In response to this determination, MN 104A searches the table (e.g., Table 1-3 or Table 1-4) and identifies that the configuration ID for cell ID 1 is configuration ID 1. MN 104A then includes configuration ID 1 in the CHO release configuration and sends the CHO release configuration to UE 102. UE 102 releases CHO command 1 based on configuration ID 1 in the CHO release configuration. If the cell ID has a configuration state of "Unconfigured" or is not found in the table, MN 104A may not send any CHO release configuration to UE 102 to release the CHO command for the cell ID.

[0147] In other implementations, MN 104A has / stores a table (eg, Table 2-1) that selects a configuration ID for a CHO command (ie, assigns a new configuration ID or identifies an existing configuration ID) for UE 102. The table includes entries for cell IDs and configuration IDs.

[0148] Table 2-1

[0149] Cell ID Configuration ID

[0150] In one example, before the MN 104A receives a CHO command (e.g., CHO command 1 530D), the MN 104A may initialize the table to Table 2-1 (i.e., empty). If the cell ID of the candidate cell 510D is cell ID 1 and cell ID 1 is not in the table, the MN 104A assigns a new configuration ID (e.g., configuration ID 1) of cell ID 1 or CHO command 1 in response to the determination 510D or receipt of CHO command 1, as shown in Table 2-2.

[0151] Table 2-2

[0152] Cell ID Configuration ID Cell ID 1 Configuration ID1

[0153] In another example, before MN 104A receives CHO command 530D (e.g., CHO command 2), MN 104A has a table as shown in Table 2-2. If the cell ID of candidate cell 510D is cell ID 1, MN 104A uses configuration ID 1 for CHO command 2 according to the table and sends configuration ID 1 and CHO command 2 at event 534D. If the cell ID of candidate cell 510D is cell ID 2 and cell ID 2 is not in the table, MN 104A allocates a new configuration ID (e.g., configuration ID 2) for cell ID 2 or CHO command 2 in response to determination 510D or receipt 530D of CHO command 2, as shown in Table 2-3, and sends configuration ID 2 and CHO command 2 at event 534D. That is, if the MN 104A determines to configure a conditional handover to a specific cell ID, or if the MN 104A receives a CHO command for a specific cell ID, the MN 104A looks up the table using the specific cell ID (eg, cell ID1) as an index.

[0154] Table 2-3

[0155] Cell ID Configuration ID Cell ID 1 Configuration ID1 Cell ID2 Configuring ID2

[0156] If MN 104A determines to release a CHO command for a cell ID or receives a request from C-MN 106A to release a CHO command for a cell ID, MN 104A searches the table using the cell ID as an index to find the configuration ID for the cell ID and may send a CHO release configuration including the configuration ID. UE 102 releases the CHO command based on the configuration ID in the CHO release configuration. For example, MN 104A may determine to release a CHO command for cell ID 1. In response to this determination, MN 104A searches the table (e.g., Table 1-3 or Table 1-4) and identifies that the configuration ID for cell ID 1 is configuration ID 1. MN 104A then includes configuration ID 1 in the CHO release configuration and sends the CHO release configuration to UE 102. UE 102 releases CHO command 1 based on configuration ID 1 in the CHO release configuration. If the cell ID is not found in the table, MN 104A may not send any CHO release configuration to UE 102 to release the CHO command for the cell ID.

[0157] As mentioned above Figure 3A As discussed, in one implementation, a CHO command (e.g., CHO command 1) includes information specifying a condition for conditional handover (i.e., a conditional configuration for the condition). MN 104A may generate an RRC container message including the CHO command and, at event 534D, send the CHO command to UE 102. In this implementation, MN 104A generates an RRC container message including the CHO command and the conditional configuration and, at event 534D, sends the RRC container message to UE 102. In some implementations, UE 102 sends an RRC container response message to MN 104A in response to the RRC container message.

[0158] As described above, Figures 6 to 8 correspond to the conditional SN add / change scenario where the wireless communication system 100 uses the configuration identifier to track the candidate SN configuration. Figures 6A to 6C , shows a conditional SN add or change scenario, where the configuration identifier used to manage / track the configuration is a transaction ID.

[0159] exist Figure 6A In the conditional SN add or SN change scenario 600A, the base station 104A operates as the MN of the UE 102, and the base station 106A operates as the candidate SN (C-SN) of the UE 102. Initially, the UE 102 is in single connectivity (SC) operation with the MN 104A or with the Figure 6A SN 104B, not shown in FIG, transmits 602A data (e.g., UL data PDUs and / or DL data PDUs) in dual connectivity. MN 104A then, at some point, for example, blindly or in response to detecting a suitable event (e.g., as described above with reference to FIG). Figure 3A (as discussed) determine 612A configure the conditional SN of UE 102 to be added or changed.

[0160] After determining 612A that a conditional SN addition or change is configured, the MN 104A assigns 620A a specific transaction ID to the conditional SN addition / change or, equivalently, assigns 620A to the C-SN configuration associated with the conditional SN addition / change. In the depicted scenario, the assigned identifier is "transaction ID1." As described above, as used herein, (and unless a more specific meaning is clear from the context in which it is used) "assigning" a configuration identifier may refer to the act of initially selecting an identifier (i.e., for a completely new configuration), or to the subsequent selection of a previously selected / used identifier (i.e., when attempting to modify an existing configuration). For example, a transaction ID may be similar to that described above with reference to Figure 3A The transaction ID in question (e.g., the transaction ID specified in 3GPP TS 36.331 or 38.331).

[0161] In response to determining 612A, and after assigning 620A transaction ID 1, MN 104A sends 628A an SN request message (e.g., an SN add request or an SN modify request message) including transaction ID 1 to C-SN 106A. In response to the SN request message, C-SN 106A includes the assigned transaction ID (transaction ID 1) in or via a C-SN configuration ("C-SN configuration 1"). That is, C-SN configuration 1 is identified by or associated with transaction ID 1. C-SN 106A includes C-SN configuration 1 in an SN request confirm message (e.g., an SN add request confirm or an SN modify request confirm message) and sends 632A an SN request confirm message to MN 104A in response to the SN request message. C-SN configuration 1 includes one or more configurations of candidate cells (e.g., candidate PSCells (C-PSCells)) for C-MN 106A.

[0162] MN 104A then sends 636A C-SN configuration 1 (including transaction ID 1) to UE 102. UE 102 identifies the transaction ID and, based on its value (transaction ID 1), adds or modifies 642A the configuration. Specifically, using the received C-SN configuration, UE 102 identifies the transaction ID to add a C-SN configuration or to modify a C-SN configuration stored in UE 102. If UE 102 identifies a stored C-SN configuration that has previously been used with the transaction ID (i.e., transaction ID 1 is associated with the stored C-SN configuration), UE 102 modifies the stored C-SN configuration with C-SN configuration 1. In some cases, UE 102 replaces the stored C-SN configuration with C-SN configuration 1. In other cases, UE 102 replaces only a subset of the configuration parameters in the stored C-SN configuration with one or more configuration parameters in C-SN configuration 1. If UE 102 instead determines that transaction ID 1 is a new transaction ID, UE 102 stores C-SN configuration 1 as the new C-SN configuration.

[0163] In some scenarios, 612A to 642A may be repeated for one or more conditional SN additions and / or changes. For example, MN 104A may later assign "transaction ID 2" to "C-SN configuration 2" received by UE 102 (e.g., after another transmission similar to transmission 636A). UE 102 may then store C-SN configuration 2 as a new configuration (if transaction ID 2 is different from transaction ID 1 and is not used for any other C-SN configuration already stored at UE 102 and not yet released), or use C-SN configuration 2 to replace part or all of a pre-existing (i.e., already stored and not released) C-SN configuration that also includes (or is otherwise associated with) transaction ID 2.

[0164] In one implementation and scenario, after UE 102 adds 642A C-SN configuration 1 or modifies 642A the C-SN configuration using C-SN configuration 1, and before UE 102 releases C-SN configuration 1, UE 102 determines 646A that the cell satisfies the conditions for accessing a candidate cell of C-SN 106A and, in response, initiates 650A a random access procedure on the candidate cell. In the depicted scenario, the candidate cell is the cell for which MN 104A determines 612A that the configuration conditions SN are added or changed.

[0165] UE 102 then performs 654A a random access procedure with C-SN 106A via the candidate cell according to the configuration of C-SN configuration 1 (e.g., random access preamble, etc.). If UE 102 instead determines 646A that conditions for a different candidate cell are met, UE 102 performs 654A a random access procedure with C-SN 106A (or possibly another base station) via the other candidate cell according to the corresponding C-SN configuration. Operations 646A, 650A, and 654A are performed in Figure 6A are collectively referred to as Process 690A.

[0166] In some implementations, the MN 104A indicates to the C-SN 106A in the SN request message that the base station 106A is being requested for the purpose of conditional PSCell addition / change for the UE 102 (ie, requested to be the C-SN for the UE 102).

[0167] In one implementation, the C-SN configuration includes information specifying a condition for conditional SN addition or change (i.e., a conditional configuration for the condition). At event 636A, MN 104A may generate an RRC container message including the C-SN configuration and send the RRC container message (without a separate conditional configuration) to UE 102. Alternatively, the C-SN configuration may not include the conditional configuration, and MN 104A includes the conditional configuration along with the C-SN configuration in an SN request confirm message. In this implementation, MN 104A generates an RRC container message including the C-SN configuration and the conditional configuration and sends the RRC container message to UE 102 at event 636A. In yet another implementation, the SN request confirm message and the C-SN configuration do not include the conditional configuration, and MN 104A configures the condition. In such an implementation, MN 104A also generates an RRC container message including the C-SN configuration and the conditional configuration and sends the RRC container message to UE 102 at event 636A. In either of these implementations, UE 102 may send an RRC container response message to MN 104A in response to receiving the RRC container message. Additionally, MN 104A may send an SN reconfiguration complete message to C-SN 106A in response to receiving the RRC container message.

[0168] In some implementations (e.g., for (NG)EN-DC and NR-NR DC operations), the C-SN configuration includes one or more cell group configuration (CellGroupConfig) information elements (IEs). In one implementation, the C-SN 106A includes an RRCReconfiguration message that includes the CellGroupConfig IE in an SN Request Ack message and sends the RRCReconfiguration message to the UE 102 at event 636A. In other implementations, the C-SN configuration is an RRCReconfiguration message that includes the CellGroupConfig IE. For example, the RRCReconfiguration message and the CellGroupConfig IE may be as defined in 3GPP TS 38.331.

[0169] In some implementations (e.g., for NE-DC operation), the C-SN configuration is the SCG-ConfigPartSCG-r12 IE. In one implementation, the C-SN 106A includes an RRCConnectionReconfiguration message that includes the ConfigPartSCG-r12 IE in the SN Add Request Confirm message. In other implementations, the C-SN configuration is an RRCConnectionReconfiguration message that includes the ConfigPartSCG-r12 IE. For example, the RRCConnectionReconfiguration message and the SCG-ConfigPartSCG-r12 IE may be as defined in 3GPP TS 36.331.

[0170] Figure 6A Starting with UE 102 communicating in SC operation, Figure 6B Depicts a conditional SN change scenario 600B, where the UE 102 initially communicates in DC operation. Figure 6B 6, base station 104A acts as the MN for UE 102, and base station 106A acts as the SN for UE 102 (supporting PSCell), wherein UE 102 communicates 603B with MN 104A and SN 106A while operating in DC. SN 106A then, at some point, for example, blindly or in response to detecting a suitable event (e.g., as described above with reference to FIG. 6, ). Figure 3A (as discussed) determines 612B to configure a conditional SN change for UE 102. In the depicted scenario, the SN change is to a different PSCell also supported by SN 106A.

[0171] After determining 612B that the conditional SN change has been configured, the SN 106A assigns 620B a specific transaction ID to the conditional SN change or equivalently assigns 620B to the C-SN configuration associated with the conditional SN change. In the depicted scenario, the assigned identifier is "transaction ID 1". For example, the transaction ID may be similar to that described above with reference to Figure 3A The transaction ID discussed herein (e.g., the transaction ID specified in 3GPP TS 36.331 or 38.331). It should be understood that in other scenarios, MN 104A may instead perform 612B and 620B (e.g., as Figure 6A ), even though UE 102 operates in DC with MN 104A and SN (e.g., base station 106B).

[0172] In response to determining 612B, and after assigning 620B transaction ID 1, SN 106A sends 629A a C-SN configuration ("C-SN configuration 1") including transaction ID 1 to MN 104A. For example, the C-SN configuration may be similar to that described above with reference to Figure 6A After receiving C-SN configuration 1, MN 104A sends C-SN configuration 1 (including transaction ID 1) to UE 102. UE 102 then identifies the transaction ID and, based on its value (transaction ID 1), adds or modifies 642B configuration (e.g., as described above with reference to Figure 6A In some scenarios, 612B to 642B may be repeated for one or more conditional SN changes, as discussed above.

[0173] In one implementation and scenario, after UE 102 adds 642B C-SN configuration 1 or modifies 642B the C-SN configuration using C-SN configuration 1, and before UE 102 releases C-SN configuration 1, UE 102 determines 647B that conditions for connecting to a candidate PSCell are met, and in response, initiates 651B a random access procedure on the candidate PSCell. In the depicted scenario, the candidate PSCell is the cell for which SN 106A determines 612B that the configuration conditions are changed.

[0174] UE 102 then performs 655B a random access procedure with SN 106A via the candidate PSCell according to the configuration of C-SN configuration 1 (e.g., random access preamble, etc.), and thereafter communicates 656B with MN 104A and SN 106A via the PSCell using C-SN configuration 1 in DC operation. If UE 102 instead determines 647B that the conditions of a different candidate PSCell are met, then in DC operation, UE 102 performs 655B a random access procedure via the other PSCell, and thereafter communicates 656B with MN 104A and SN 106A via the other PSCell using the corresponding C-SN configuration. Operations 647B, 651B, 655B, and 656B are performed in Figure 6B are collectively referred to as Process 691B.

[0175] In one implementation, the C-SN configuration generated by SN 106A includes information specifying the conditions for the conditional SN change (i.e., the conditional configuration for the condition). At event 636B, MN 104A may generate an RRC container message including the C-SN configuration and send the RRC container message (without the separate conditional configuration) to UE 102. Alternatively, the C-SN configuration provided by SN 106A may not include the conditional configuration, and MN 104A includes the conditional configuration along with the C-SN configuration in the RRC container message that MN 104A sends to UE 102 at event 636B. In either of these implementations, UE 102 may send an RRC container response message to MN 104A in response to receiving the RRC container message.

[0176] Figure 6C A conditional SN change scenario 600C is depicted that is similar to scenario 600B, but in which UE 102 is configured to an SRB through an SN and can therefore receive a C-SN configuration directly from the SN. In scenario 600C, UE 102 initially communicates in DC operation. Specifically, Figure 6C 6, base station 104A acts as the MN for UE 102, and base station 106A acts as the SN for UE 102 (supporting PSCell), wherein UE 102 communicates 603B with MN 104A and SN 106A while operating in DC. SN 106A then, at some point, for example, blindly or in response to detecting a suitable event (e.g., as described above with reference to FIG. 6, ). Figure 3A (as discussed) determines 612C to configure a conditional SN change for UE 102. In the depicted scenario, the SN change is to a different PSCell also supported by SN 106A.

[0177] After determining 612C that the conditional SN change has been configured, the SN 106A assigns 620C a specific transaction ID to the conditional SN change or equivalently assigns 620C to the C-SN configuration associated with the conditional SN change. In the depicted scenario, the assigned identifier is "transaction ID 1". For example, the transaction ID may be similar to that described above with reference to Figure 3A The transaction ID in question (eg, the transaction ID specified in 3GPP TS 36.331 or 38.331).

[0178] In response to determining 612C, and after allocating 620C transaction ID 1, SN 106A sends 637C a C-SN configuration ("C-SN configuration 1") including transaction ID 1 to UE 102. For example, the C-SN configuration may be similar to that described above with reference to Figure 6A After receiving C-SN configuration 1, UE 102 identifies the transaction ID and, based on its value (transaction ID 1), adds or modifies 642 the C configuration (e.g., as described above with reference to Figure 6A In some scenarios, 612C to 642C may be repeated for one or more conditional SN changes, as discussed above.

[0179] In one implementation and scenario, after the UE 102 adds 642C C-SN configuration 1 or modifies 642C C-SN configuration using C-SN configuration 1, and before the UE 102 releases C-SN configuration 1, in process 691C, the UE 102 determines that the conditions for connecting to the candidate PSCell are met, initializes and performs a random access procedure on the candidate PSCell, and communicates with the SN 106A (via the candidate PSCell) and the MN 104A in DC. For example, process 691C may be similar to Figure 6B Process 691B.

[0180] Next reference Figures 7A to 7C , shows a conditional SN add or SN change scenario, where the configuration identifier used to manage / track the configuration is the cell ID.

[0181] exist Figure 7A In the conditional SN add or SN change scenario 700A, the base station 104A operates as the MN of the UE 102, and the base station 106A operates as the C-SN of the UE 102. Initially, the UE 102 is in single connectivity (SC) operation with the MN 104A or with the Figure 7A SN 104B, not shown in FIG, transmits 702A data (eg, UL data PDUs and / or DL data PDUs) with dual connectivity. MN 104A then at some point, for example, blindly or in response to detecting a suitable event (as described above with reference to FIG. Figure 3AAs discussed, determine 712A to configure a conditional SN addition or SN change for the UE 102 (eg, to a candidate PSCell).

[0182] After determining 712A, the MN 104A assigns 720A a cell ID to the C-SN configuration. In the depicted scenario, the MN 104A assigns an identifier "Cell ID 1" to the C-SN configuration, where Cell ID 1 identifies a candidate cell (e.g., a C-PSCell) for which the MN 104A is configuring a conditional SN add or SN change. In various implementations, the cell ID can be a physical cell ID (PCI, e.g., as specified in 3GPP TS 36.323 or 38.423), a cell global ID (CGI), or another suitable identifier for a specific cell in the wireless communication system 100. In some implementations, as discussed further below, the MN 104A does not assign 720A Cell ID 1, but instead includes a cell identifier from which Cell ID 1 can be later derived (e.g., by the C-SN 106A).

[0183] In response to determining 712A, and after assigning 720A cell ID 1, MN 104A sends 728A an SN request message (e.g., an SN add request or an SN modify request message) to C-SN 106A, including cell ID 1. In response, C-SN 106A includes the assigned cell ID (cell ID 1) in or via a C-SN configuration ("C-SN configuration 1"). C-SN 106A includes C-SN configuration 1 in an SN request confirm message (e.g., an SN add request confirm or an SN modify request confirm message) and sends 732A an SN request confirm message to MN 104A in response to the SN request message. In some implementations, cell ID 1 is a specific PCI value that C-SN 106A derives from the CGI value that MN 104A included in the SN request message. In this implementation, the "allocation" at event 720A may be considered to be a combination of (1) determining the CGI at MN 104A and (2) deriving the PCI from the CGI at C-SN 106A. In other implementations, the same cell identifier (e.g., CGI or PCI) is included in both the SN Request message and the SN Request Ack message. For example, C-SN Configuration 1 may be similar to that described above with reference to FIG. 1 , except that the cell ID is used as the configuration identifier. Figure 6A The C-SN configuration 1 discussed above and the SN request and SN request confirmation messages may be similar to those in the reference Figure 6A Discuss the SN request and SN request confirmation messages.

[0184] MN 104A then sends 736A C-SN configuration 1 (including cell ID 1) to UE 102. UE 102 identifies the cell ID and, based on its value (cell ID 1), adds or modifies 742A the configuration (e.g., to match the configuration described above with reference to Figure 6A 736A). In some scenarios, 712A to 742A may be repeated for one or more conditional SN additions and / or changes. For example, MN 104A may later assign "cell ID 2" to "C-SN configuration 2" received by UE 102 (e.g., after another transmission similar to transmission 736A). UE 102 may then store C-SN configuration 2 as a new configuration (if cell ID 2 is different from cell ID 1 and is not used for any other C-SN configuration already stored at UE 102 and not released), or use C-SN configuration 2 to replace part or all of a pre-existing (i.e., already stored and not released) C-SN configuration that also includes (or is otherwise associated with) cell ID 2.

[0185] In one implementation and scenario, after the UE 102 adds 742A C-SN configuration 1 or modifies 742A C-SN configuration using C-SN configuration 1, and before the UE 102 releases C-SN configuration 1, in process 790A (e.g., similar to Figure 6A In process 690A), UE 102 determines that the conditions for accessing a candidate cell of C-SN 106A are met, and in response, initializes and performs a random access procedure on the candidate cell.

[0186] In one implementation, the C-SN configuration includes information specifying a condition for conditional SN addition or change (i.e., a conditional configuration for the condition). At event 736A, MN 104A may generate an RRC container message including the C-SN configuration and send the RRC container message (without a separate conditional configuration) to UE 102. Alternatively, the C-SN configuration may not include the conditional configuration, and MN 104A includes the conditional configuration along with the C-SN configuration in an SN request confirm message. In this implementation, MN 104A generates an RRC container message including the C-SN configuration and the conditional configuration and sends the RRC container message to UE 102 at event 736A. In yet another implementation, the SN request confirm message and the C-SN configuration do not include the conditional configuration, and MN 104A configures the condition. In this implementation, MN 104A also generates an RRC container message including the C-SN configuration and the conditional configuration and sends the RRC container message to UE 102 at event 736A. In either of these implementations, UE 102 may send an RRC container response message to MN 104A in response to receiving the RRC container message. Additionally, MN 104A may send an SN reconfiguration complete message to C-SN 106A in response to receiving the RRC container message.

[0187] exist Figure 7B 104A acts as the MN for UE 102, and base station 106A acts as the SN for UE 102 (supporting PSCell), wherein UE 102 communicates 703B with MN 104A and SN 106A while operating in DC. SN 106A then, at some point, for example, blindly or in response to detecting a suitable event (e.g., as described above with reference to FIG. 104B ), initiates a call to the MN 104A and SN 106A. Figure 3A (as discussed) determines 712B to configure a conditional SN change for UE 102. In the depicted scenario, the SN change is to a different PSCell also supported by SN 106A.

[0188] After determining 712B that the configuration conditional SN change has occurred, the SN 106A assigns 720B a specific cell ID to the C-SN configuration associated with the conditional SN change. In the depicted scenario, the assigned identifier is "Cell ID 1". The cell ID may be similar to that described above with reference to Figure 7AAfter allocating 720B cell ID 1, SN 106A sends 729B a C-SN configuration including cell ID 1 ("C-SN configuration 1") to MN 104A. After receiving C-SN configuration 1, MN 104A sends 736B C-SN configuration 1 (including cell ID 1) to UE 102. UE 102 then identifies the cell ID and, based on its value (cell ID 1), adds or modifies 742B a configuration (e.g., as described above with reference to FIG). Figure 6A In some scenarios, 712B to 742B may be repeated for one or more conditional SN changes, as discussed above.

[0189] In one implementation and scenario, after the UE 102 adds 742B C-SN configuration 1 or modifies 742B C-SN configuration using C-SN configuration 1, and before the UE 102 releases C-SN configuration 1, in process 791B (e.g., similar to process 691B), the UE 102 determines that conditions for connecting to the candidate PSCell are met, initializes and performs a random access procedure on the candidate PSCell, and then communicates with the SN 106A on the candidate PSCell using C-SN configuration 1.

[0190] In one implementation, the C-SN configuration generated by SN 106A includes information specifying the conditions for the conditional SN change (i.e., the conditional configuration for the condition). At event 736B, MN 104A may generate an RRC container message including the C-SN configuration and send the RRC container message (without the separate conditional configuration) to UE 102. Alternatively, the C-SN configuration provided by SN 106A may not include the conditional configuration, and MN 104A includes the conditional configuration along with the C-SN configuration in the RRC container message that MN 104A sends to UE 102 at event 736B. In either of these implementations, UE 102 may send an RRC container response message to MN 104A in response to receiving the RRC container message.

[0191] Figure 7C A conditional SN change scenario 700C is depicted that is similar to scenario 700B, but in which the UE 102 is configured to an SRB through the SN and can therefore receive a C-SN configuration directly from the SN. In scenario 700C, the UE 102 initially communicates in DC operation. Specifically, Figure 7C104A acts as the MN for UE 102, and base station 106A acts as the SN for UE 102 (supporting PSCell), wherein UE 102 communicates 703C with MN 104A and SN 106A while operating in DC. SN 106A then, at some point, for example, blindly or in response to detecting a suitable event (e.g., as described above with reference to FIG. 104A ), initiates a call to the MN 104A and SN 106A. Figure 3A (as discussed) determines 712C to configure a conditional SN change for UE 102. In the depicted scenario, the SN change is to a different PSCell also supported by SN 106A.

[0192] After determining 712C that the conditional SN configuration has changed, the SN 106A assigns 720C a specific cell ID to the C-SN configuration associated with the conditional SN change. In the depicted scenario, the assigned identifier is "Cell ID 1". For example, the cell ID may be similar to that described above with reference to Figure 7A The cell ID in question (e.g., PCI or CGI).

[0193] After allocating 720C cell ID 1, SN 106A sends 737C a C-SN configuration ("C-SN configuration 1") including cell ID 1 to UE 102. For example, the C-SN configuration may be similar to that described above with reference to Figure 7A After receiving C-SN configuration 1, UE 102 identifies the cell ID and, based on its value (cell ID 1), adds or modifies 742 the C configuration (e.g., as described above with reference to Figure 6A In some scenarios, 712C to 742C may be repeated for one or more conditional SN changes, as discussed above.

[0194] In one implementation and scenario, after the UE 102 adds 742C C-SN configuration 1 or modifies 742C C-SN configuration using C-SN configuration 1, and before the UE 102 releases C-SN configuration 1, in process 791C, the UE 102 determines that the conditions for connecting to the candidate PSCell are met, initializes and performs a random access procedure on the candidate PSCell, and communicates with the SN 106A (via the candidate PSCell) and the MN 104A in DC. For example, process 791C may be similar to Figure 6B Process 691B.

[0195] Next reference Figures 8A to 8F , shows a conditional SN add or SN change scenario, where the configuration identifier used to manage / track the configuration is a dedicated configuration identifier.

[0196] exist Figure 8AIn the conditional SN add or SN change scenario 800A, the base station 104A operates as the MN of the UE 102, and the base station 106A operates as the C-SN of the UE 102. Initially, the UE 102 is in single connectivity (SC) operation with the MN 104A or with the Figure 8A SN 104B, not shown in FIG, transmits 802A data (eg, UL data PDUs and / or DL data PDUs) with dual connectivity. MN 104A then at some point, for example, blindly or in response to detecting a suitable event (as described above with reference to FIG. Figure 3A (as discussed) determines 812A to configure a conditional SN addition or SN change for the UE 102.

[0197] After determining 812A, the MN 104A assigns 820A a dedicated configuration identifier to the C-SN configuration. In the depicted scenario, the MN 104A assigns the identifier "Configuration ID1" to the C-SN configuration. For example, the dedicated configuration identifier may be similar to that described above with reference to Figure 5A Described dedicated configuration identifier.

[0198] After assigning 820A configuration ID 1, MN 104A sends 828A an SN request message (e.g., an SN add request or an SN modify request message) including configuration ID 1 to C-SN 106A. In one implementation, MN 104A determines a candidate PSCell at event 812A. In another implementation, C-SN 106A configures the candidate PSCell in the C-SN configuration. The candidate PSCell is associated with a cell ID (e.g., cell ID 1). In some implementations, C-SN 106A determines the candidate PSCell based on RRC configuration information (e.g., CG-ConfigInfo as defined in TS 38.331) received (from MN 104A to C-SN 106A) in SN request message 828A. In response, the C-SN 106A includes the assigned configuration ID (Configuration ID 1) in or via the C-SN configuration ("C-SN Configuration 1"). The C-SN 106A includes the C-SN Configuration 1 in an SN Request Confirmation message (e.g., an SN Add Request Confirmation message or an SN Modify Request Confirmation message) and sends an SN Request Confirmation message 832A to the MN 104A in response to the SN Request message. For example, the C-SN Configuration 1 may be similar to the configuration ID described above with reference to FIG. 1 , except that a dedicated configuration identifier is used. Figure 6A The C-SN configuration 1 discussed above and the SN request and SN request confirmation messages may be similar to those in the reference Figure 6A Discuss the SN request and SN request confirmation messages.

[0199] MN 104A then sends 836A C-SN configuration 1 (including configuration ID 1) to UE 102. UE 102 identifies the configuration identifier and, based on its value (configuration ID 1), adds or modifies 842A the configuration (e.g., to match the configuration ID 1 described above). Figure 6A 836A). In some scenarios, 812A to 842A may be repeated for one or more conditional SN additions and / or changes. For example, MN 104A may later assign "configuration ID 2" to "C-SN configuration 2" received by UE 102 (e.g., after another transmission similar to transmission 836A). UE 102 may then store C-SN configuration 2 as a new configuration (if configuration ID 2 is different from configuration ID 1 and is not used in any other CHO command already stored at UE 102 and not yet released), or use C-SN configuration 2 to replace part or all of a pre-existing (i.e., already stored and not released) C-SN configuration that also includes (or is otherwise associated with) configuration ID 2.

[0200] In one implementation and scenario, after the UE 102 adds 842A C-SN configuration 1 or modifies 842A C-SN configuration using C-SN configuration 1, and before the UE 102 releases C-SN configuration 1, in process 890A (e.g., similar to Figure 6A In process 690A), UE 102 determines that the conditions for accessing a candidate cell of C-SN 106A are met, and in response, initializes and performs a random access procedure on the candidate cell.

[0201] In one implementation, the C-SN configuration includes information specifying a condition for conditional SN addition or change (i.e., a conditional configuration for the condition). At event 836A, MN 104A may generate an RRC container message including the C-SN configuration and send the RRC container message (without a separate conditional configuration) to UE 102. Alternatively, the C-SN configuration may not include the conditional configuration, and MN 104A includes the conditional configuration along with the C-SN configuration in an SN request confirm message. In this implementation, MN 104A generates an RRC container message including the C-SN configuration and the conditional configuration and sends the RRC container message to UE 102 at event 836A. In yet another implementation, the SN request confirm message and the C-SN configuration do not include the conditional configuration, and MN 104A configures the condition. In this implementation, MN 104A also generates an RRC container message including the C-SN configuration and the conditional configuration and sends the RRC container message to UE 102 at event 836A. In either of these implementations, UE 102 may send an RRC container response message to MN 104A in response to receiving the RRC container message. Additionally, MN 104A may send an SN reconfiguration complete message to C-SN 106A in response to receiving the RRC container message.

[0202] exist Figure 8B 803B, SN 106A may then, at some point, for example, blindly or in response to detecting a suitable event (e.g., as described above with reference to FIGURE 804B), communicate with MN 104A and SN 106A. Figure 3A (as discussed) determines 812B to configure a conditional SN change for UE 102. In the depicted scenario, the SN change is to a different PSCell (e.g., a candidate PSCell) that is also supported by SN 106A.

[0203] After determining 812B that a conditional SN change has been configured, SN 106A assigns 820B a dedicated configuration identifier to the C-SN configuration associated with the conditional SN change. SN 106A configures a candidate PSCell in the C-SN configuration. The candidate PSCell is associated with a cell ID (e.g., cell ID 1). In some implementations, SN 106A determines the candidate PSCell based on one or more measurements received from UE 102 (e.g., via SRB3, MN 104A, or a physical uplink control channel) or measured by SN 106A on one or more transmissions from UE 102. In the depicted scenario, the assigned identifier is "Configuration ID 1." For example, the dedicated configuration identifier may be similar to that described above with reference to FIG. Figure 5A Described dedicated configuration identifier.

[0204] After allocating 820B configuration ID 1, SN 106A sends 829B the C-SN configuration and configuration ID 1 to MN 104A. In some implementations, SN 106A includes configuration ID 1 in the C-SN configuration ("C-SN Configuration 1"). In some implementations, SN 106A may send an SN message including C-SN Configuration 1 to MN 104A at event 829B. After receiving C-SN Configuration 1, MN 104A sends 836B C-SN Configuration 1 (including configuration ID 1) to UE 102. In other implementations, SN 106A does not include configuration ID 1 in C-SN Configuration 1. Instead, in some implementations, SN 106A sends an SN message including C-SN Configuration 1 and configuration ID 1 to MN 104A at event 829B. After receiving C-SN configuration 1 and configuration ID 1, MN 104A includes configuration ID 1 and C-SN configuration 1 in an RRC container message instead of C-SN configuration 1 alone, and sends 836B the RRC container message to UE 102. In some implementations, the SN message may be an SN modification request message (e.g., S-NODE MODIFICATION REQUIRED or SgNB MODIFICATION REQUIRED), an SN modification request confirmation message (e.g., S-NODE MODIFICATION REQUEST ACKNOWLEDGE or SgNB MODIFICATION REQUEST ACKNOWLEDGE), or an SN change request message (e.g., S-NODE CHANGE REQUIRED or SgNB CHANGE REQUIRED), an SN release request message (e.g., S-NODE RELEASE REQUIRED or SgNB RELEASE REQUIRED), or an SN release request confirmation message (e.g., S-NODERELEASE REQUEST ACKNOWLEDGE or SgNB RELEASE REQUEST ACKNOWLEDGE).

[0205] The UE 102 then identifies the configuration identifier and, based on its value (Configuration ID 1), adds or modifies (e.g., replaces) 842B the stored C-SN configuration (e.g., adds C-SN configuration 1 or replaces the stored C-SN configuration with C-SN configuration 1, e.g., as described above with reference to Figure 6AIn some scenarios, 812B to 842B may be repeated for one or more conditional SN changes, as discussed above. In one implementation and scenario, after UE 102 adds 842B C-SN configuration 1 or modifies 842B C-SN configuration using C-SN configuration 1, and before UE 102 releases C-SN configuration 1, in process 891B (e.g., similar to Figure 6B In process 691B), UE 102 determines that conditions for connecting to a candidate PSCell are met, initializes and performs a random access procedure on the candidate PSCell, and then communicates with SN 106A on the candidate PSCell using C-SN configuration 1.

[0206] In one implementation, the C-SN configuration generated by SN 106A includes information specifying the conditions for the conditional SN change (i.e., the conditional configuration for the condition). At event 836B, MN 104A may generate an RRC container message including the C-SN configuration and send the RRC container message (without the separate conditional configuration) to UE 102. Alternatively, the C-SN configuration provided by SN 106A may not include the conditional configuration, and MN 104A includes the conditional configuration along with the C-SN configuration in the RRC container message that MN 104A sends to UE 102 at event 836B. In either of these implementations, UE 102 may send an RRC container response message to MN 104A in response to receiving the RRC container message.

[0207] In some implementations, the SN 106A includes a table of configuration IDs (e.g., Table 1-1) for the UE 102 to select and configure the C-SN configuration of a candidate PSCell associated with a cell ID. The table includes entries for the cell ID, configuration ID, and configuration status (e.g., whether the cell has been configured for the UE 102 for conditional PSCell addition or change (CPAC)). In some implementations, the MN 104A or the SN 106A can be configured by the O&M node using the table. The O&M node can reconfigure (e.g., update) the table. For example, the O&M node can reconfigure the table by adding a new entry including a new cell ID with a configuration status of "unconfigured" and a new configuration ID. In other implementations, the SN 106A can be configured by default or manually using the table.

[0208] In one example, SN 106A maintains the table, and SN 106A may initialize the table to Table 1-2 before SN 106A generates the C-SN configuration. If the cell ID of the candidate PSCell is cell ID 1, SN 106A sets the configuration state of cell ID 1 to "configured" in response to determination 812B, as shown in Table 1-3. SN 106A uses configuration ID 1 for C-SN configuration 1 according to the table because C-SN configuration 1 is used for cell ID 1, and MN 104A in turn sends configuration ID 1 and C-SN configuration 1 at event 836B. That is, if SN 106A determines to configure CPAC to a cell identified by a specific cell ID, SN 106A uses the specific cell ID (e.g., cell ID 1) as an index to look up the table.

[0209] In another example, before SN 106A generates the C-SN configuration sent at event 829B, SN 106A has / stores the table shown in Table 1-3. If the cell ID of the candidate PSCell is cell ID 1, SN 106A may or may not set the configuration state of cell ID 1 to "configured" in response to determination 812B, as shown in Table 1-3. Because C-SN configuration 1 is for cell ID 1, SN 106A uses configuration ID 1 for C-SN configuration 1 according to the table and sends configuration ID 1 and C-SN configuration 1 at event 829B. If the cell ID of the candidate PSCell is cell ID 2, SN 106A sets the configuration state of cell ID 2 to "configured" in response to determination 812B, as shown in Table 1-4. Because C-SN configuration 2 is for cell ID 2, SN 106A uses configuration ID 2 for C-SN configuration 2 according to the table and sends configuration ID 2 and C-SN configuration 2 at event 829B. That is, if the SN 106A determines to configure the CPAC to a specific cell ID, the SN 106A looks up the table using the specific cell ID (eg, cell ID 1) as an index.

[0210] If SN 106A determines to release the C-SN configuration for the cell ID with the configuration state "Configured," SN 106A finds the configuration ID for the cell ID by looking up the table using the cell ID as an index, and may send a CPAC release configuration including the configuration ID to UE 102 via MN 104A. For example, SN 106A includes the CPAC release configuration at event 829B, while MN 104A includes the CPAC release configuration at event 836B. UE 102 releases the C-SN configuration based on the configuration ID in the CPAC release configuration. For example, SN 106A determines to release the C-SN configuration for cell ID 1. In response to the determination, SN 106A looks up the table (e.g., Table 1-3 or Table 1-4) and identifies that the configuration ID for cell ID 1 is configuration ID 1. SN 106A then includes configuration ID 1 in the CPAC release configuration and sends the CPAC release configuration to UE 102 via MN 104A. For example, SN 106A includes a CPAC release configuration at event 829B, while MN 104 includes a CPAC release configuration at event 836B. UE 102 releases C-SN configuration 1 according to configuration ID 1 in the CPAC release configuration. If the cell ID has a configuration state of "unconfigured" or is not found in the table, SN 106A may not send any CPAC release configuration to UE 102 to release the C-SN configuration for the cell ID.

[0211] In other implementations, SN 106A has / stores a table (eg, Table 2-1) of configuration IDs for UE 102 to select C-SN configurations (ie, assign new configuration IDs or identify existing configuration IDs). The table includes entries for cell IDs and configuration IDs.

[0212] In one example, before SN 106A generates a C-SN configuration (e.g., C-SN configuration 1 sent at event 829B), SN 106A may initialize the table to Table 2-1 (i.e., empty). If the cell ID of the candidate PSCell is cell ID 1 and cell ID 1 is not in the table, SN 106A assigns a new configuration ID (e.g., configuration ID 1) to cell ID 1 or the C-SN configuration in response to determination 812B, as shown in Table 2-2.

[0213] In another example, before SN 106A generates the C-SN configuration (e.g., C-SN configuration 2) sent at event 829B, SN 106A has / stores a table as Table 2-2. If the cell ID of the candidate PSCell is cell ID 1, SN 106A uses configuration ID 1 for C-SN configuration 2 according to the table and sends configuration ID 1 and C-SN configuration 2 at event 836B. If the cell ID of the candidate PSCell is cell ID 2 and cell ID 2 is not in the table, SN 106A assigns a new configuration ID (e.g., configuration ID 2) to cell ID 2 or C-SN configuration 2 in response to determination 812B, as shown in Table 2-3, and MN 104A sends configuration ID 2 and C-SN configuration 2 at event 836B. That is, if SN 106A determines to configure CPAC to a specific cell ID, SN 106A uses the specific cell ID (e.g., cell ID 1) as an index to look up the table.

[0214] If SN 106A determines to release the C-SN configuration for the cell ID, SN 106A searches the table to find the configuration ID for the cell ID using the cell ID as an index, and may send a CPAC release configuration including the configuration ID. UE 102 releases the C-SN configuration according to the configuration ID in the CPAC release configuration. For example, SN 106A determines to release the C-SN configuration for cell ID 1. In response to the determination, SN 106A searches the table (e.g., Table 1-3 or Table 1-4) and identifies that the configuration ID for cell ID 1 is configuration ID 1. SN 106A then includes configuration ID 1 in the CPAC release configuration and sends the CPAC release configuration to UE 102. UE 102 releases C-SN configuration 1 according to configuration ID 1 in the CPAC release configuration. If the cell ID is not found in the table, SN 106A may not send any CPAC release configuration to UE 102 to release the C-SN configuration for the cell ID.

[0215] Figure 8C A conditional SN change scenario 800C is depicted that is similar to scenario 800B, but in which the UE 102 is configured to an SRB through the SN and can therefore receive a C-SN configuration directly from the SN. In scenario 800C, the UE 102 initially communicates in DC operation. Specifically, Figure 8C 803C, UE 102 communicates with MN 104A and SN 106A while operating in DC. SN 106A then, at some point, for example, blindly or in response to detecting a suitable event (e.g., as described above with reference to FIG. 804C), initiates a call to MN 104A and SN 106A. Figure 3A(as discussed) determines 812C to configure a conditional SN change for UE 102. In the depicted scenario, the SN change is to a different PSCell also supported by SN 106A.

[0216] After determining 812C that the configuration conditional SN has changed, the SN 106A assigns 820C a dedicated configuration identifier to the C-SN configuration associated with the conditional SN change. In the depicted scenario, the assigned identifier is "Configuration ID1". For example, the dedicated configuration identifier may be similar to that described above with reference to Figure 5A The identifier of the dedicated configuration in question.

[0217] After allocating 820C cell ID 1, SN 106A sends 837C a C-SN configuration including configuration ID 1 ("C-SN configuration 1") to UE 102. For example, the C-SN configuration may be similar to that described above with reference to Figure 8A After receiving C-SN configuration 1, UE 102 identifies the configuration identifier and, based on its value (configuration ID 1), adds or modifies 842 the C configuration (e.g., as described above with reference to Figure 6A In some scenarios, 812C to 842C may be repeated for one or more conditional SN changes, as discussed above.

[0218] In one implementation and scenario, after the UE 102 adds 842C C-SN configuration 1 or modifies 842C C-SN configuration using C-SN configuration 1, and before the UE 102 releases C-SN configuration 1, in process 891C (e.g., similar to Figure 6B In process 691B), UE 102 determines that conditions for connecting to a candidate PSCell are met, initializes and performs a random access procedure on the candidate PSCell, and communicates with SN 106A (via the candidate PSCell) and MN 104A in DC.

[0219] In some implementations, the SN 106A has / stores a table (e.g., Table 1-1) of configuration IDs that the UE 102 selects for C-SN configuration. The table includes entries for a cell ID, a configuration ID, and a configuration status (e.g., whether the cell has been configured for CPAC to the UE 102). In some implementations, the SN 106A can be configured by the O&M node using the table. The O&M node can reconfigure (e.g., update) the table. For example, the O&M node can reconfigure the table by adding a new entry including a new cell ID with a configuration status of "unconfigured" and a new configuration ID. In other implementations, the SN 106A can be configured by default or manually using the table.

[0220] In one example, SN 106A maintains the table, and SN 106A may initialize the table to Table 1-2 before SN 106A generates the C-SN configuration. If the cell ID of the candidate PSCell is cell ID 1, SN 106A sets the configuration state of cell ID 1 to "configured" in response to determination 812C, as shown in Table 1-3. Because C-SN configuration 1 is for cell ID 1, SN 106A uses configuration ID 1 for C-SN configuration 1 according to the table, and in turn transmits configuration ID 1 and C-SN configuration 1 at event 837C. That is, if SN 106A determines to configure CPAC to a specific cell ID using SRB3, SN 106A uses the specific cell ID (e.g., cell ID 1) as an index to look up the table.

[0221] In another example, before SN 106A generates the C-SN configuration sent at event 837C, SN 106A has / stores the table shown in Table 1-3. If the cell ID of the candidate PSCell is cell ID 1, SN 106A may or may not set the configuration state of cell ID 1 to "configured" in response to determination 812C, as shown in Table 1-3. Because C-SN configuration 1 is for cell ID 1, SN 106A uses configuration ID 1 for C-SN configuration 1 according to the table and sends configuration ID 1 and C-SN configuration 1 at event 837C. If the cell ID of the candidate PSCell is cell ID 2, SN 106A sets the configuration state of cell ID 2 to "configured" in response to determination 812C, as shown in Table 1-4. Because C-SN configuration 2 is for cell ID 2, SN 106A uses configuration ID 2 for C-SN configuration 2 according to the table and sends configuration ID 2 and C-SN configuration 2 at event 837C. That is, if the SN 106A determines to configure the CPAC to a specific cell ID, the SN 106A looks up the table using the specific cell ID (eg, cell ID 1) as an index.

[0222] If SN 106A determines to release the C-SN configuration for a cell ID with a configuration state of "Configured," SN 106A searches the table to find the configuration ID for the cell ID using the cell ID as an index, and may send a CPAC release configuration including the configuration ID. UE 102 releases the C-SN configuration based on the configuration ID in the CPAC release configuration. For example, SN 106A determines to release the C-SN configuration for cell ID 1. In response to this determination, SN 106A searches the table (e.g., Table 1-3 or Table 1-4) and identifies that the configuration ID for cell ID 1 is configuration ID 1. SN 106A then includes configuration ID 1 in the CPAC release configuration and sends the CPAC release configuration to UE 102. UE 102 releases C-SN configuration 1 based on configuration ID 1 in the CPAC release configuration. If the cell ID has a configuration state of "Unconfigured" or is not found in the table, SN 106A may not send any CPAC release configuration to UE 102 to release the C-SN configuration for the cell ID.

[0223] In other implementations, SN 106A has / stores a table (eg, Table 2-1) of configuration IDs for UE 102 to select C-SN configurations (ie, assign new configuration IDs or identify existing configuration IDs). The table includes entries for cell IDs and configuration IDs.

[0224] In one example, before the SN 106A generates a C-SN configuration (e.g., C-SN configuration 1 sent at 837C), the SN 106A may initialize the table to Table 2-1 (i.e., empty). If the cell ID of the candidate PSCell is cell ID 1 and cell ID 1 is not in the table, the SN 106A assigns a new configuration ID (e.g., configuration ID 1) to cell ID 1 or the C-SN configuration in response to determination 812C, as shown in Table 2-2.

[0225] In another example, before SN 106A generates C-SN configuration 837C (e.g., C-SN configuration 2), SN 106A has / stores a table as Table 2-2. If the cell ID of the candidate PSCell is cell ID 1, SN 106A uses configuration ID 1 for C-SN configuration 2 according to the table and transmits configuration ID 1 and C-SN configuration 2 at event 837C. If the cell ID of the candidate PSCell is cell ID 2 and cell ID 2 is not in the table, SN 106A assigns a new configuration ID (e.g., configuration ID 2) to cell ID 2 or C-SN configuration 2 in response to determination 812C, as shown in Table 2-3, and transmits configuration ID 2 and C-SN configuration 2 at event 837C. That is, if SN 106A determines to configure CPAC to a specific cell ID, SN 106A uses the specific cell ID (e.g., cell ID 1) as an index to look up the table.

[0226] If SN 106A determines to release the C-SN configuration for the cell ID, SN 106A searches the table to find the configuration ID for the cell ID using the cell ID as an index, and may send a CPAC release configuration including the configuration ID. UE 102 releases the C-SN configuration according to the configuration ID in the CPAC release configuration. For example, SN 106A determines to release the C-SN configuration for cell ID 1. In response to the determination, SN 106A searches the table (e.g., Table 1-3 or Table 1-4) and identifies that the configuration ID for cell ID 1 is configuration ID 1. SN 106A then includes configuration ID 1 in the CPAC release configuration and sends the CPAC release configuration to UE 102. UE 102 releases C-SN configuration 1 according to configuration ID 1 in the CPAC release configuration. If the cell ID is not found in the table, SN 106A may not send any CPAC release configuration to UE 102 to release the C-SN configuration for the cell ID.

[0227] exist Figure 8D In the conditional SN add or SN change scenario 800D, the base station 104A operates as the MN of the UE 102, and the base station 106A operates as the C-SN of the UE 102. Initially, the UE 102 is in single connectivity (SC) operation with the MN 104A or with the Figure 8D SN 104B, not shown in FIG, transmits 802D data (eg, UL data PDUs and / or DL data PDUs) with dual connectivity. MN 104A then at some point, for example, blindly or in response to detecting a suitable event (as described above with reference to FIG. Figure 3A (as discussed) determines 812D to configure the conditional SN addition or SN change of the UE 102.

[0228] After determining 812D, MN 104A sends 828D an SN request message (e.g., an SN add request or SN modify request message) to C-SN 106A that does not include a dedicated configuration identifier. In one implementation, MN 104A determines a candidate PSCell at event 812D. In another implementation, C-SN 106A configures the candidate PSCell in the C-SN configuration. The candidate PSCell is associated with a cell ID (e.g., cell ID 1). In some implementations, C-SN 106A determines the candidate PSCell based on MN-to-SNRRC configuration information (e.g., CG-ConfigInfo as defined in TS 38.331) received in SN request message 828D. In response, C-SN 106A sends 832D an SN request confirm message (e.g., an SN add request confirm or SN modify request confirm message) to MN 104A that includes the C-SN configuration for C-SN 106A ("C-SN Configuration 1"). For example, C-SN configuration 1 may be similar to that described above with reference to Figure 6A The C-SN configuration 1 discussed above and the SN request and SN request confirmation messages may be similar to those in the reference Figure 6A SN Request and SN Request Confirm messages discussed. In one implementation, along with the C-SN configuration, the SN Request Confirm message contains the cell ID.

[0229] After receiving the SN request confirmation message, the MN 104A assigns 820D a dedicated configuration identifier to the C-SN configuration. In the depicted scenario, the MN 104A assigns the identifier "Configuration ID1" to the C-SN configuration. For example, the dedicated configuration identifier may be similar to that described above with reference to Figure 5A Described dedicated configuration identifier.

[0230] MN 104A then sends 836D C-SN configuration 1 to UE 102, but now wherein C-SN configuration 1 includes configuration ID 1, or wherein both configuration ID 1 and C-SN configuration 1 are included in the same RRC container message. UE 102 identifies the configuration identifier and, based on its value (configuration ID 1), adds or modifies 842D the configuration (e.g., to match the configuration ID 1 described above). Figure 6A In some scenarios, repetitions 812D to 842D may be added and / or changed for one or more conditional SNs, as discussed above.

[0231] In one implementation and scenario, after the UE 102 adds 842D C-SN configuration 1 or modifies 842D C-SN configuration using C-SN configuration 1, and before the UE 102 releases C-SN configuration 1, in process 890D (e.g., similar to Figure 6AIn process 690A), UE 102 determines that the conditions for accessing a candidate cell of C-SN 106A are met, and in response, initializes and performs a random access procedure on the candidate cell.

[0232] In one implementation, the C-SN configuration includes information specifying a condition for conditional SN addition or change (i.e., a conditional configuration for the condition). At event 836D, MN 104A may generate an RRC container message including the C-SN configuration and send the RRC container message (without a separate conditional configuration) to UE 102. Alternatively, the C-SN configuration may not include the conditional configuration, and C-SN 106A includes the conditional configuration along with the C-SN configuration in an SN request confirm message. In this implementation, MN 104A generates an RRC container message including the C-SN configuration and the conditional configuration and sends the RRC container message to UE 102 at event 836D. In yet another implementation, the SN request confirm message and the C-SN configuration do not include the conditional configuration, and MN 104A configures the condition. In this implementation, MN 104A also generates an RRC container message including the C-SN configuration and the conditional configuration and sends the RRC container message to UE 102 at event 836D. In any of these implementations, UE 102 may send an RRC container response message to MN 104A in response to receiving the RRC container message. Furthermore, MN 104A may send an SN reconfiguration complete message to C-SN 106A in response to receiving the RRC container message. If both Configuration ID 1 and C-SN Configuration 1 are included in the RRC container message (i.e., the Configuration ID is not included in the C-SN configuration), MN 104A includes the Configuration ID in the RRC container message.

[0233] In some implementations, the MN 104A has / stores a table of configuration IDs (e.g., Table 1-1) for the UE 102 to select and configure the C-SN configuration of a candidate PSCell associated with a cell ID. The table consists of entries for the cell ID, configuration ID, and configuration status (e.g., whether the cell has been configured for CPAC for the UE 102). In some implementations, the MN 104A can be configured by an operations and maintenance (O&M) node using the table. The O&M node can reconfigure (e.g., update) the table. For example, the O&M node can reconfigure the table by adding a new entry including a new cell ID with a configuration status of "unconfigured" and a new configuration ID. In other implementations, the MN 104A can be configured by default or manually using the table.

[0234] In one example, MN 104A maintains the table and can initialize the table to Table 1-2 before MN 104A receives the C-SN configuration. If the cell ID of the candidate PSCell received at event 832D is cell ID 1, MN 104A sets the configuration state of cell ID 1 to "configured," as shown in Table 1-3. Because C-SN configuration 1 is for cell ID 1, MN 104A uses configuration ID 1 for C-SN configuration 1 according to the table, and then MN 104A sends configuration ID 1 and C-SN configuration 1 at event 836D. That is, if C-SN 106A configures CPAC to a specific cell ID, MN 104A uses the specific cell ID (e.g., cell ID 1) as an index to look up the table.

[0235] In another example, before MN 104A receives the C-SN configuration sent at event 832D, MN 104A has the table shown in Table 1-3. If the cell ID of the candidate PSCell is Cell ID 1, MN 104A may or may not set the configuration state of Cell ID 1 to "Configured," as shown in Table 1-3. Because C-SN configuration 1 is used for Cell ID 1, MN 104A uses configuration ID 1 for C-SN configuration 1 according to the table and sends configuration ID 1 and C-SN configuration 1 at event 836D. If the cell ID of the candidate PSCell is Cell ID 2, MN 104A sets the configuration state of Cell ID 2 to "Configured," as shown in Table 1-4. Because C-SN configuration 2 is used for Cell ID 2, MN 104A uses configuration ID 2 for C-SN configuration 2 according to the table and sends configuration ID 2 and C-SN configuration 2 at event 836D. That is, if the C-SN 106A determines to configure CPAC to a specific cell ID, the MN 104A looks up the table using the specific cell ID (eg, cell ID 1) as an index.

[0236] If C-SN 106A determines to release the C-SN configuration of the cell ID with the configuration state "Configured", MN 104A searches the table to find the configuration ID of the cell ID using the cell ID as an index, and may send a CPAC release configuration including the configuration ID. UE 102 releases the C-SN configuration according to the configuration ID in the CPAC release configuration. For example, C-SN 106A determines to release the C-SN configuration of cell ID 1. After receiving the PSCell to release, MN 104A searches the table (e.g., Table 1-3 or Table 1-4) and identifies that the configuration ID of cell ID 1 is configuration ID 1. MN 104A then includes configuration ID 1 in the CPAC release configuration and sends the CPAC release configuration to UE 102. UE 102 releases C-SN configuration 1 according to configuration ID 1 in the CPAC release configuration. If the cell ID has a configuration status of "unconfigured" or is not found in the table, the MN 104A may not send any CPAC release configuration to the UE 102 to release the C-SN configuration for the cell ID.

[0237] In other implementations, MN 104A has a table (eg, Table 2-1) for selecting a configuration ID for a C-SN configuration (ie, assigning a new configuration ID or identifying an existing configuration ID) for UE 102. The table includes entries for cell IDs and configuration IDs.

[0238] In one example, before MN 104A receives a C-SN configuration (e.g., C-SN configuration 1 sent at event 832D), MN 104A may initialize the table to Table 2-1 (i.e., empty). If the cell ID of the candidate PSCell is cell ID 1 and cell ID 1 is not in the table, MN 104A assigns a new configuration ID (e.g., configuration ID 1) to cell ID 1 or the C-SN configuration, as shown in Table 2-2.

[0239] In another example, before MN 104A receives the C-SN configuration (e.g., C-SN configuration 2) sent at event 832D, MN 104A has / stores a table as Table 2-2. If the cell ID of the candidate PSCell is cell ID 1, MN 104A uses configuration ID 1 for C-SN configuration 2 according to the table and sends configuration ID 1 and C-SN configuration 2 at event 836D. If the cell ID of the candidate PSCell is cell ID 2 and cell ID 2 is not in the table, MN 104A assigns a new configuration ID (e.g., configuration ID 2) to cell ID 2 or C-SN configuration 2, as shown in Table 2-3, and MN 104A sends configuration ID 2 and C-SN configuration 2 at event 836D. That is, if MN 104A determines to configure CPAC to a specific cell ID, MN 104A uses the specific cell ID (e.g., cell ID 1) as an index to look up the table.

[0240] If C-SN 106A determines to release the C-SN configuration for the cell ID, MN 104A searches the table to find the configuration ID for the cell ID using the cell ID as an index and may send a CPAC release configuration including the configuration ID. UE 102 releases the C-SN configuration based on the configuration ID in the CPAC release configuration. For example, C-SN 106A determines to release the C-SN configuration for cell ID 1. In response to the determination, MN 104A searches the table (e.g., Table 1-3 or Table 1-4) and identifies that the configuration ID for cell ID 1 is configuration ID 1. MN 104A then includes configuration ID 1 in the CPAC release configuration and sends the CPAC release configuration to UE 102. UE 102 releases C-SN configuration 1 based on configuration ID 1 in the CPAC release configuration. If the cell ID is not found in the table, MN 104A may not send any CPAC release configuration to UE 102 to release the C-SN configuration for the cell ID.

[0241] exist Figure 8E 8, base station 104A acts as the MN for UE 102, and base station 106A acts as the SN for UE 102 (providing a PSCell), wherein UE 102 communicates 803E with MN 104A and SN 106A while operating in DC. SN 106A then, at some point, for example, blindly or in response to detecting a suitable event (e.g., as described above with reference to FIG. 8, 104A), initiates a call to the MN 104A and SN 106A. Figure 3A8 (discussed) determines 812E to configure a conditional SN change for UE 102. In the depicted scenario, the SN change is to a different PSCell (i.e., a candidate PSCell) also supported by SN 106A. In some implementations, the candidate PSCell may belong to SN 106A. In other implementations, the candidate PSCell may belong to base station 106B.

[0242] After determining 812E that the conditional SN change has been configured, SN 106A generates a C-SN configuration associated with the conditional SN change (e.g., C-SN configuration 1). SN 106A configures a candidate PSCell in the C-SN configuration. The candidate PSCell is associated with a cell ID (e.g., cell ID 1). In some implementations, SN 106A determines the candidate PSCell based on one or more measurements received from UE 102 (e.g., via SRB3, MN 104A, or a physical uplink control channel) or measured by SN 106A on one or more transmissions from UE 102.

[0243] After generating C-SN Configuration 1, SN 106A sends 829E the C-SN configuration to MN 104A. MN 104A then assigns 820E a dedicated configuration ID ("Configuration ID 1") to the C-SN configuration. In some implementations, SN 106A includes Configuration ID 1 ("C-SN Configuration 1") in the C-SN configuration. In some implementations, SN 106A may send an SN message including C-SN Configuration 1 to MN 104A at event 829E. After receiving C-SN Configuration 1, MN 104A sends 836E C-SN Configuration 1 (including Configuration ID 1) to UE 102. In other implementations, SN 106A does not include Configuration ID 1 in C-SN Configuration 1. Instead, in some implementations, SN 106A sends an SN message including C-SN Configuration 1 and Configuration ID 1 to MN 104A at event 829E. After receiving C-SN configuration 1 and configuration ID 1, MN 104A includes configuration ID 1 and C-SN configuration 1 (instead of C-SN configuration 1 alone) in an RRC container message and sends 836E the RRC container message to UE 102. In some implementations, the SN message may be an SN modification request message (e.g., S-NODE MODIFICATION REQUIRED or SgNB MODIFICATION REQUIRED), an SN modification request confirmation message (e.g., S-NODE MODIFICATION REQUEST ACKNOWLEDGE or SgNB MODIFICATION REQUEST ACKNOWLEDGE), or an SN change request message (e.g., S-NODE CHANGEREQUIRED or SgNB CHANGE REQUIRED), an SN release request message (e.g., S-NODE RELEASE REQUIRED or SgNB RELEASE REQUIRED), or an SN release request confirmation message (e.g., S-NODE RELEASE REQUEST ACKNOWLEDGE or SgNB RELEASE REQUEST ACKNOWLEDGE).

[0244] The UE 102 then identifies the configuration identifier and, based on its value (Configuration ID 1), adds or modifies (e.g., replaces) 842E the stored C-SN configuration (e.g., adds C-SN configuration 1 or replaces the stored C-SN configuration with C-SN configuration 1), e.g., as described above with reference to Figure 6AIn some scenarios, 812E to 842E may be repeated for one or more conditional SN changes, as discussed above. In one implementation and scenario, after UE 102 adds 842E C-SN configuration 1 or modifies (e.g., replaces) 842E a stored C-SN configuration with C-SN configuration 1, and before UE 102 releases C-SN configuration 1, in process 891E (e.g., similar to Figure 6B In process 691B), UE 102 determines that conditions for connecting to a candidate PSCell are met, initializes and performs a random access procedure on the candidate PSCell, and then communicates with SN 106A using C-SN configuration 1 on the candidate PSCell.

[0245] In one implementation, the C-SN configuration generated by SN 106A includes information specifying the condition for the conditional SN change (i.e., the conditional configuration for the condition). At event 836E, MN 104A may generate an RRC container message including the C-SN configuration and send the RRC container message (without the separate conditional configuration) to UE 102. Alternatively, the C-SN configuration provided by SN 106A may not include the conditional configuration, and MN 104A includes the conditional configuration along with the C-SN configuration in the RRC container message that MN 104A sends to UE 102 at event 836E. In either of these implementations, UE 102 may send an RRC container response message to MN 104A in response to receiving the RRC container message.

[0246] In some implementations, MN 104A has / stores a table and selects a configuration ID for UE 102 based on the received cell ID and the C-SN configuration from SN 106A. In one example, MN 104A maintains the table and can initialize the table to Table 1-2 when or before MN 104A receives the C-SN configuration. If the cell ID of the candidate PSCell received at event 829E is cell ID 1, MN 104A sets the configuration state of cell ID 1 to "configured," as shown in Table 1-3. At event 820E, because C-SN configuration 1 is for cell ID 1, MN 104A uses configuration ID 1 for C-SN configuration 1 according to the table, and MN 104A in turn sends configuration ID 1 and C-SN configuration 1 at event 836E. That is, if SN 106A configures a conditional SN change (eg, CPAC) to a specific cell ID, MN 104A looks up the table using the specific cell ID (eg, cell ID1) received in event 829E as an index.

[0247] In another example, before MN 104A receives C-SN configuration 830B, MN 104A has / stores the table shown in Table 1-3. If the cell ID of the candidate PSCell received at event 829E is cell ID 1, MN 104A may or may not set the configuration state of cell ID 1 to "configured," as shown in Table 1-3. At event 820E, because C-SN configuration 1 is used for cell ID 1, MN 104A uses configuration ID 1 for C-SN configuration 1 according to the table and transmits configuration ID 1 and C-SN configuration 1 at event 836E. If the cell ID of the candidate PSCell received at event 829E is cell ID 2, MN 104A sets the configuration state of cell ID 2 to "configured," as shown in Table 1-4. At event 820E, because C-SN configuration 2 is for cell ID 2, MN 104A uses configuration ID 2 for C-SN configuration 2 according to the table and transmits configuration ID 2 and C-SN configuration 2 at event 836E. That is, if SN 106A determines to configure CPAC to a specific cell ID, MN 104A uses the specific cell ID (e.g., cell ID 1) as an index to look up the table.

[0248] If SN 106A determines to release the C-SN configuration for the cell ID with the configuration state "Configured," MN 104A looks up the table to find the configuration ID for the cell ID using the cell ID received at 829E as an index and may send a CPAC release configuration including the configuration ID. UE 102 releases the C-SN configuration according to the configuration ID in the CPAC release configuration. For example, SN 106A determines to release the C-SN configuration for cell ID 1. After receiving the PSCell to release, at event 820E, MN 104A looks up the table (e.g., Table 1-3 or Table 1-4) and identifies that the configuration ID for cell ID 1 is configuration ID 1. MN 104A then includes configuration ID 1 in the CPAC release configuration and sends the CPAC release configuration to UE 102. UE 102 releases C-SN configuration 1 according to configuration ID 1 in the CPAC release configuration. If the cell ID has a configuration status of "unconfigured" or is not found in the table, the MN 104A may not send any CPAC release configuration to the UE 102 to release the C-SN configuration for the cell ID.

[0249] In other implementations, MN 104A has a table (eg, Table 2-1) for selecting a configuration ID for a C-SN configuration (ie, assigning a new configuration ID or identifying an existing configuration ID) for UE 102. The table includes entries for cell IDs and configuration IDs.

[0250] In one example, before MN 104A receives a C-SN configuration (e.g., C-SN configuration 1 received at event 829E), MN 104A may initialize the table to Table 2-1 (i.e., empty). If the cell ID of the candidate PSCell received at event 829E is cell ID 1 and cell ID 1 is not in the table, MN 104A assigns a new configuration ID (e.g., configuration ID 1) to cell ID 1 or the C-SN configuration, as shown in Table 2-2.

[0251] In another example, at event 829E, before MN 104A receives a C-SN configuration (e.g., C-SN configuration 2), MN 104A has a table as Table 2-2. If the cell ID of the candidate PSCell received at event 829E is cell ID 1, MN 104A uses configuration ID 1 for C-SN configuration 2 according to the table and sends configuration ID 1 and C-SN configuration 2 at event 836E. If the cell ID of the candidate PSCell received at event 829E is cell ID 2 and cell ID 2 is not in the table, MN 104A assigns a new configuration ID (e.g., configuration ID 2) to cell ID 2 or C-SN configuration 2, as shown in Table 2-3, and MN 104A sends configuration ID 1 and C-SN configuration 2 at event 836E. That is, if the MN 104A determines to configure CPAC to a specific cell ID, the MN 104A uses the specific cell ID (eg, cell ID 1) received in event 829E as an index to look up the table.

[0252] If SN 106A determines to release the C-SN configuration for the cell ID, MN 104A searches the table to find the configuration ID for the cell ID using the cell ID as an index and may send a CPAC release configuration including the configuration ID. UE 102 releases the C-SN configuration according to the configuration ID in the CPAC release configuration. For example, SN 106A determines to release the C-SN configuration for cell ID 1. In response to this determination, at event 820E, MN 104A searches the table (e.g., Table 1-3 or Table 1-4) and identifies that the configuration ID for cell ID 1 is configuration ID 1. MN 104A then includes configuration ID 1 in the CPAC release configuration and sends the CPAC release configuration to UE 102. UE 102 releases C-SN configuration 1 according to configuration ID 1 in the CPAC release configuration. If the cell ID is not found in the table, MN 104A may not send any CPAC release configuration to UE 102 to release the C-SN configuration for the cell ID.

[0253] exist Figure 8FIn the conditional SN add or SN change scenario 800F, base station 104A operates as the MN of UE 102, and base station 106A operates as the C-SN of UE 102. Initially, UE 102 operates in single connectivity with MN 104A or with SN 104B ( Figure 8F ) transmits 802F data (e.g., UL data PDUs and / or DL data PDUs) with dual connectivity. The MN 104A then at some point, for example blindly or in response to detecting a suitable event (as described above with reference to Figure 3A (as discussed) determines 812F to configure the conditional SN addition or SN change of UE 102.

[0254] After determining 812F, the MN 104A sends 828F an SN request message (e.g., an SN add request or SN modify request message) to the C-SN 106A that does not include a dedicated configuration identifier. The C-SN 106A configures the candidate PSCell in the C-SN configuration. The candidate PSCell is associated with a cell ID (e.g., cell ID 1). In some implementations, the C-SN 106A determines the candidate PSCell based on the MN-to-SN RRC configuration information (e.g., CG-ConfigInfo defined in TS 38.331) received in the SN request message sent 828F. In response, the C-SN 106A sends 832F an SN request confirm message (e.g., an SN add request confirm or SN modify request confirm message) to the MN 104A that includes the C-SN configuration for the C-SN 106A ("C-SN Configuration 1"). SN 106A allocates 820F a dedicated configuration identifier ("C-SN configuration ID1") for C-SN configuration 1 and may include the configuration identifier in the C-SN configuration or in the SN request confirmation message. For example, C-SN configuration 1 may be similar to that described above with reference to Figure 6A The C-SN configuration 1 discussed above and the SN request and SN request confirmation messages may be similar to those in the reference Figure 6A The SN request and SN request confirmation messages discussed. In one implementation, the SN request confirmation message includes the cell ID and the C-SN configuration.

[0255] MN 104A then sends 836F C-SN configuration 1 to UE 102, but now wherein C-SN configuration 1 includes configuration ID 1, or wherein both configuration ID 1 and C-SN configuration 1 are included in the same RRC container message. UE 102 identifies the configuration identifier and, based on its value (configuration ID 1), adds or modifies (e.g., replaces) 842F the configuration (e.g., to match the configuration ID 1 described above). Figure 6AIn some scenarios, repetitions 812F to 842F may be added and / or changed for one or more conditional SNs, as discussed above.

[0256] In one implementation and scenario, after UE 102 adds 842F C-SN configuration 1 or modifies (e.g., replaces) 842F C-SN configuration with C-SN configuration 1, and before UE 102 releases C-SN configuration 1, in process 890F (e.g., similar to Figure 6A In process 690A), UE 102 determines that the conditions for accessing a candidate cell of C-SN 106A are met, and in response, initializes and performs a random access procedure on the candidate cell.

[0257] In one implementation, the C-SN configuration includes information specifying the condition for conditional SN addition or change (i.e., the conditional configuration for the condition). MN 104A may generate an RRC container message including the C-SN configuration and, at event 836F, send the RRC container message (without the separate conditional configuration) to UE 102. Alternatively, the C-SN configuration may not include the conditional configuration, and C-SN 106A includes the conditional configuration along with the C-SN configuration in the SN Request Confirm message. In this implementation, MN 104A generates an RRC container message including the C-SN configuration and the conditional configuration and, at event 836F, sends the RRC container message to UE 102. In yet another implementation, the SN Request Confirm message and the C-SN configuration do not include the conditional configuration, and MN 104A configures the condition. In such an implementation, MN 104A also generates an RRC container message including the C-SN configuration and the conditional configuration and, at event 836F, sends the RRC container message to UE 102. In any of these implementations, in response to receiving the RRC container message, UE 102 may send an RRC container response message to MN 104A. Furthermore, in response to receiving the RRC container message, MN 104A may send an SN reconfiguration complete message to C-SN 106A. If both Configuration ID 1 and C-SN Configuration 1 are included in the RRC container message (i.e., the Configuration ID is not included in the C-SN configuration), MN 104A includes the Configuration ID in the RRC container message.

[0258] In some implementations, the C-SN 106A has / stores a table of configuration IDs (e.g., Table 1-1) for the UE 102 to select and configure the C-SN configuration of a candidate PSCell associated with a cell ID. The table consists of entries for the cell ID, configuration ID, and configuration status (e.g., whether the cell has been configured for CPAC for the UE 102). In some implementations, the MN 104A or the C-SN 106A can be configured by the O&M node using the table. The O&M node can reconfigure (e.g., update) the table. For example, the O&M node can reconfigure the table by adding a new entry including a new cell ID with a configuration status of "unconfigured" and a new configuration ID. In other implementations, the C-SN 106A can be configured by default or manually using the table.

[0259] In one example, C-SN 106A maintains the table and may initialize the table to Table 1-2 before generating the C-SN configuration. If the cell ID of the candidate PSCell is cell ID 1, C-SN 106A sets the configuration state of cell ID 1 to "configured," as shown in Table 1-3. Because C-SN configuration 1 is for cell ID 1, C-SN 106A uses configuration ID 1 for C-SN configuration 1 according to the table and sends configuration ID 1 and C-SN configuration 1 to MN 104A at event 832F. MN 104A then sends configuration ID 1 and C-SN configuration 1 at event 836F. That is, if C-SN 106A determines to configure CPAC to a cell identified by a specific cell ID, C-SN 106A uses the specific cell ID (e.g., cell ID 1) as an index to look up the table.

[0260] In another example, before C-SN 106A generates the C-SN configuration sent at event 832F, C-SN 106A has / stores the table shown in Table 1-3. If the cell ID of the candidate PSCell is cell ID 1, C-SN 106A may or may not set the configuration state of cell ID 1 to "configured." Because C-SN configuration 1 is used for cell ID 1, C-SN 106A uses configuration ID 1 for C-SN configuration 1 according to the table and sends configuration ID 1 and C-SN configuration 1 to MN 104A at event 832F. MN 104A then sends configuration ID 1 and C-SN configuration 1 at event 836F. If the cell ID of the candidate PSCell is cell ID 2, C-SN 106A sets the configuration state of cell ID 2 to "configured," as shown in Table 1-4. Because C-SN configuration 2 is for cell ID 2, C-SN 106A uses configuration ID 2 for C-SN configuration 2 according to the table and transmits configuration ID 2 and C-SN configuration 2 at event 832F. That is, if C-SN 106A determines to configure CPAC to a specific cell ID, C-SN 106A uses the specific cell ID (e.g., cell ID 1) as an index to look up the table.

[0261] If the C-SN 106A determines to release the C-SN configuration of the cell ID having the configuration state "configured", the C-SN 106A looks up the table to find the configuration ID of the cell ID by using the cell ID as an index, and may send a CPAC release configuration including the configuration ID to the UE 102 via the MN 104A. For example, the C-SN 106A includes the CPAC release configuration at event 832F or in an SN message (e.g., as shown in FIG. Figure 8E ), and then, MN 104 includes a CPAC release configuration at event 836F or in another RRC container message. UE 102 releases the C-SN configuration according to the configuration ID in the CPAC release configuration. For example, C-SN 106A determines to release the C-SN configuration of cell ID 1. In response to the determination, C-SN 106A looks up the table (e.g., Table 1-3 or Table 1-4) and identifies that the configuration ID of cell ID 1 is configuration ID 1. C-SN 106A then includes configuration ID 1 in the CPAC release configuration and sends the CPAC release configuration to UE 102 via MN 104A. UE 102 releases C-SN configuration 1 according to configuration ID 1 in the CPAC release configuration. If the cell ID has a configuration state of "unconfigured" or is not found in the table, SN 106A may not send any CPAC release configuration to UE 102 to release the C-SN configuration for the cell ID.

[0262] In other implementations, C-SN 106A has / stores a table (eg, Table 2-1) of configuration IDs for UE 102 to select C-SN configurations (ie, assign new configuration IDs or identify existing configuration IDs). The table includes entries for cell IDs and configuration IDs.

[0263] In one example, before the C-SN 106A generates a C-SN configuration (e.g., C-SN Configuration 1 sent at event 832F), the C-SN 106A may initialize the table to Table 2-1 (i.e., empty). If the cell ID of the candidate PSCell is Cell ID 1 and Cell ID 1 is not in the table, the C-SN 106A assigns a new configuration ID (e.g., Configuration ID 1) to Cell ID 1 or the C-SN configuration in response to the SN Request message 828F, as shown in Table 2-2.

[0264] In another example, before C-SN 106A generates the C-SN configuration (e.g., C-SN configuration 2) sent at event 832F, SN 106A has / stores a table as Table 2-2. If the cell ID of the candidate PSCell is cell ID 1, C-SN 106A uses configuration ID 1 for C-SN configuration 2 according to the table and sends configuration ID 1 and C-SN configuration 2 to MN 104A at event 832F. MN 104A then sends configuration ID 1 and C-SN configuration 1 at event 836F. If the cell ID of the candidate PSCell is cell ID 2 and cell ID 2 is not in the table, C-SN 106A assigns a new configuration ID (e.g., configuration ID 2) to cell ID 2 or C-SN configuration 2, as shown in Table 2-3, and MN 104A sends configuration ID 2 and C-SN configuration 2 at event 836F. That is, if the C-SN 106A determines to configure the CPAC to a specific cell ID, the C-SN 106A uses the specific cell ID (eg, cell ID 1) as an index to look up the table.

[0265] If the C-SN 106A determines to release the C-SN configuration of the cell ID, the C-SN 106A looks up the table to find the configuration ID of the cell ID by using the cell ID as an index, and may send a CPAC release configuration including the configuration ID. The UE 102 releases the C-SN configuration according to the configuration ID in the CPAC release configuration. For example, the C-SN 106A determines to release the C-SN configuration of the cell ID1. In response to the determination, the C-SN 106A looks up the table (e.g., Table 1-3 or Table 1-4) and identifies that the configuration ID of the cell ID1 is configuration ID1. The C-SN 106A then includes configuration ID1 in the CPAC release configuration and sends the CPAC release configuration to the UE 102 via the MN 104A. For example, the C-SN 106A includes the CPAC release configuration in the transmission or SN message at event 832F (e.g., as Figure 8E 836F). UE 102 releases C-SN configuration 1 according to configuration ID 1 in the CPAC release configuration. If the cell ID is not found in the table, C-SN 106A may not send any CPAC release configuration to UE 102 to release the C-SN configuration for the cell ID.

[0266] As mentioned above, Figures 9A to 9C This corresponds to a scenario where the wireless communication system 100 uses a configuration identifier to release (rather than add or modify) a conditional configuration at the UE 102 .

[0267] First reference Figure 9AIn example scenario 900A, base station 104A operates as a MN for UE 102. In scenario 900A, UE 102 communicates 904A with MN 104A, and MN 104A configures a conditional configuration (e.g., by sending a CHO command or C-SN configuration to UE 102 as described above). MN 104 then sends 914A an RRC message to UE 102 including a configuration identifier for the conditional configuration to indicate to UE 102 that UE 102 should release the identified conditional configuration. For example, the configuration identifier can be any of the identifier types discussed above (e.g., a transaction ID, a cell ID, a dedicated configuration identifier, or a measurement identity). In other implementations, the identifier in transmission 914A can be a sequence number identifying the sequential position of the conditional configuration in a list. For example, if UE 102 receives CHO command 1 and CHO command 2 at event 914A, the sequence number can be 1 (or 0) for CHO command 1 and 2 (or 1) for CHO command 2. In response to receiving the RRC message, and based on the identifier in the RRC message, the UE 102 releases 944A the CHO command or C-SN configuration identified.

[0268] exist Figure 9B In example scenario 900B, base station 104A operates as the MN for UE 102, and base station 106A operates as the SN (e.g., for a PSCell) and the C-SN (e.g., for a C-PSCell) for UE 102. In scenario 900B, UE 102 communicates 905B with MN 104A and SN 106A, and MN 104A or SN 106A configures a conditional configuration by sending the C-SN configuration to UE 102 as described above.

[0269] At some point thereafter, SN 106A determines 916B to release a particular C-SN configuration associated with a C-PSCell that SN 106A also supports. In response to determination 916B, SN 106A sends 931B an SN Release / Modify Request message to MN 104A that includes an identifier of the C-SN configuration to be released. MN 104A then sends 914B an RRC message to UE 102 that includes an identifier of the C-SN configuration to be released. For example, the identifier may be the C-PSCell described above with reference to FIG. Figure 9A In response to receiving the RRC message, and based on the identifier in the RRC message, the UE 102 releases 944B the C-SN configuration identified.

[0270] exist Figure 9CIn example scenario 900C, base station 104A operates as the MN for UE 102, and base station 106A operates as the SN (e.g., for a PSCell) and the C-SN (e.g., for a C-PSCell) for UE 102. In scenario 900C, UE 102 communicates 905C with MN 104A and SN 106A, and MN 104A or SN 106A configures a conditional configuration by sending the C-SN configuration to UE 102 as described above.

[0271] At some point thereafter, SN 106A determines 916C to release a particular C-SN configuration associated with a C-PSCell that SN 106A also supports. In example scenario 900C, UE 102 is configured to an SRB through SN 106A and can therefore receive the C-SN configuration directly from SN 106A. Therefore, in response to determining 916C, SN 106A sends 915C an RRC message to UE 102 including an identifier of the C-SN configuration to be released. For example, the identifier can be the one described above with reference to Figure 9A In response to receiving the RRC message, and based on the identifier in the RRC message, the UE 102 releases 944C the C-SN configuration identified.

[0272] As described above, Figures 10 and 11 correspond to alternative implementations in which the RAN of the wireless communication system 100 provides the UE 102 with a full set of conditional handover configurations to avoid any uncertainty (at the UE 102) about the current full configuration list, where Figure 10 corresponds to a CHO scenario and Figure 11 corresponds to a conditional SN addition or change scenario.

[0273] First reference Figure 10A In example scenario 1000A, base station 104A operates as the MN for UE 102, and base station 106A operates as the C-MN for UE 102. Initially, UE 102 communicates 1006A data (e.g., UL data PDUs and / or DL data PDUs) with MN 104A, and MN 104A configures UE 102 with a CHO command 1 that configures a first candidate cell for UE 102. In scenario 1000A, it is assumed that UE 102 has not been configured with any other CHO command prior to event 1006A, or that UE 102 has released any such previous configuration.

[0274] Later, MN 104A determines 1010A to configure conditional handover for UE 102 to a second candidate cell associated with C-MN 106A. In response, the MN sends 1026A a Handover Request message to C-MN 106A, which responds by generating 1038 a CHO Command 2 (i.e., the configuration of the second candidate cell). C-MN 106A then sends 1030A a Handover Request Acknowledge message to MN 104A, including the CHO Command 2.

[0275] In this implementation, when the MN 104A receives CHO Command 2, the MN 104A generates a complete conditional configuration list or set, which in this scenario 1000A includes only CHO Command 1 and CHO Command 2. The MN 104A sends 1039A the complete conditional configuration set (i.e., CHO Command 1 and CHO Command 2) to the UE 102. In response, the UE 102 replaces 1045A all CHO commands stored in memory at the UE 102 with the received CHO commands (i.e., CHO Command 1 and CHO Command 2). Because all pre-existing CHO commands are replaced by the received set, the UE 102 does not need to determine whether the received CHO command is intended to update an existing CHO command stored in the UE 102 or is intended to be a new CHO command.

[0276] In some implementations, the MN 104A also sends the conditions associated with CHO command 1 and the conditions associated with CHO command 2 along with CHO command 1 and CHO command 2 to the UE 102. In this implementation, the UE 102 replaces all existing conditions associated with the existing CHO command with all received conditions associated with the CHO command received in transmission 1039A. Therefore, the UE 102 does not need to determine the association between pre-existing / stored conditions and the received CHO command.

[0277] Events 1060A, 1066A, 1070A, and 1076A may be similar to Figure 3A Events 360A, 366A, 370A, and 376A of FIG. 10A, but wherein the CHO completion message does not include a transaction ID (or, in some implementations, any other configuration identifier).

[0278] Figure 10BAn example scenario 1000B is depicted in which the "winning" candidate cell for conditional handover is supported by the same base station (104A) that supports the cell with which UE 102 is currently communicating (e.g., with base station 104A acting as the MN). Initially, UE 102 communicates 1006B data (e.g., UL data PDUs and / or DL data PDUs) with MN 104A, and MN 104A configures UE 102 with a CHO command 1 that configures a first candidate cell for UE 102, where the first candidate cell is another cell supported by MN 104A. In scenario 1000B, it is assumed that UE 102 has not been configured with any other CHO commands prior to event 1006B, or that UE 102 has released any such previous configuration.

[0279] 104B . MN 104A then determines 1010B to configure conditional handover for UE 102 to a second candidate cell, which may or may not be associated with MN 104A. In response, MN 104A generates 1038B CHO Command 2 (i.e., the configuration for the second candidate cell). In this implementation, in response to determination 1010B, MN 104A generates a complete list or set of conditional configurations, which in this scenario 1000B includes only CHO Command 1 and CHO Command 2. MN 104A sends 1039B the complete set of conditional configurations (i.e., CHO Command 1 and CHO Command 2) to UE 102. In response, UE 102 replaces 1045B all CHO commands (here, only CHO Command 1) stored in memory at UE 102 with the received CHO commands (i.e., CHO Command 1 and CHO Command 2). Because all pre-existing CHO commands are replaced by the received set, the UE 102 does not need to determine whether the received CHO command is intended to update an existing CHO command stored in the UE 102 or is intended to be a new CHO command.

[0280] In some implementations, the MN 104A also sends the conditions associated with CHO command 1 and the conditions associated with CHO command 2 along with CHO command 1 and CHO command 2 to the UE 102. In this implementation, the UE 102 replaces all existing conditions associated with the existing CHO command with all received conditions associated with the CHO command received in transmission 1039B. Therefore, the UE 102 does not need to determine the association between pre-existing / stored conditions and the received CHO command.

[0281] Events 1061B, 1067B, 1071B, and 1077B may be similar to Figure 3BEvents 361B, 367B, 371B, and 377B of FIG. 10 , but wherein the CHO completion message does not include the transaction ID (or, in some implementations, any other configuration identifier).

[0282] exist Figure 11A In example scenario 1100A, base station 104A operates as the MN of UE 102, base station 106A operates as the SN of UE 102, and base station 104B operates as the C-SN of UE 102. Initially, UE 102 communicates 1108A data (e.g., UL data PDUs and / or DL data PDUs) with MN 104A and SN 106A, and SN 106A configures C-SN configuration 1 for a first candidate cell for UE 102 via SRB3 (i.e., a direct SRB between SN 106A and UE 102). In scenario 1100A, it is assumed that UE 102 has not been configured with any other C-SN configuration before event 1108A, or that UE 102 has released any such previous configuration.

[0283] SN 106A later determines 1111A to configure C-SN configuration 2 of the second candidate cell to UE 102. In this implementation, SN 106A generates a complete list of conditional configurations in response to determining 1111A.

[0284] or a set, in this scenario 1100A, the list or set only includes C-SN configuration 1 and C-SN configuration

[0285] 2. SN 106A sends 1137A the complete set of conditional configurations (ie, C-SN configuration 1 and C-SN configuration 2) to UE 102 via SRB3.

[0286] In response to receiving the conditional configuration set, UE 102 replaces 1148A all stored C-SN configurations (here, only C-SN configuration 1) with the received C-SN configurations (i.e., C-SN configuration 1 and C-SN configuration 2). UE 102 does not need to determine whether the received C-SN configuration is intended to update a pre-existing C-SN configuration stored in UE 102 or is intended to be a new C-SN configuration.

[0287] Later, MN 104A determines 1113A that base station 104B is configured as the C-SN for UE 102. In response to determination 1113A, MN 104A sends 1128A an SN request message (e.g., an SN add request or an SN modify request message) to base station 104B. In response to the SN request message, base station 104B generates 1143A a C-SN configuration ("C-SN configuration X") and includes C-SN configuration X in an SN request confirm message (e.g., an SN add request confirm or an SN modify request confirm message). Base station 104B sends 1143A an SN request confirm message to MN 104A. MN 104A then sends 1149A C-SN configuration X to UE 102.

[0288] In this implementation, UE 102 adds C-SN configuration X via SRB1, but keeps the stored C-SN configurations (C-SN configuration 1 and C-SN configuration 2) unchanged via SRB3. That is, the technique for replacing all C-SN configurations can be divided according to SRB or some other suitable factor. If there are additional C-SN configurations to be delivered via SRB1, MN 104A can send C-SN configuration X and C-SN configuration Y to UE 102, so that UE 102 replaces all stored C-SN configurations via SRB1 with the C-SN configuration received via SRB1.

[0289] In some implementations, the MN 104A may also send the conditions associated with C-SN configuration 1 and the conditions associated with C-SN configuration 2, as well as C-SN configuration 1 and C-SN configuration 2, to the UE 102. In this implementation, the UE 102 replaces all existing conditions associated with the existing C-SN configuration (at least for the SRB3 C-SN configuration) with all received conditions associated with the received C-SN configuration. Therefore, the UE 102 does not need to determine whether the pre-existing conditions are associated with the received C-SN configuration.

[0290] exist Figure 11B In example scenario 1100B, base station 104A operates as the MN of UE 102, and base station 106A operates as the C-SN of UE 102. Initially, UE 102 communicates 1107B data (e.g., UL data PDUs and / or DL data PDUs) with MN 104A, and MN 104A configures C-SN configuration 1 of a first candidate cell to UE 102. In scenario 1100B, it is assumed that UE 102 has not been configured with any other C-SN configuration before event 1107B, or that UE 102 has released any such previous configuration.

[0291] MN 104A later determines 1111B to configure C-SN configuration 2 of the second candidate cell for UE 102, and in response, sends 1128B an SN request message to C-SN 106A associated with the second candidate cell. In response to the SN request message, C-SN 106A generates 1138B C-SN configuration 2 for the second candidate cell and sends 1132B an SN request confirm message including C-SN configuration 2 to MN 104A.

[0292] In this implementation, in response to receiving the SN Request Confirm message, the MN 104A generates a complete list or set of conditional configurations, which in this scenario 1100B includes only C-SN configuration 1 and C-SN configuration 2. The MN 104A sends 1141B the complete set of conditional configurations (i.e., C-SN configuration 1 and C-SN configuration 2) to the UE 102.

[0293] In response to receiving the conditional configuration set, UE 102 replaces 1148B all stored C-SN configurations (here, only C-SN configuration 1) with the received C-SN configurations (i.e., C-SN configuration 1 and C-SN configuration 2). UE 102 does not need to determine whether the received C-SN configuration is intended to update a pre-existing C-SN configuration stored in UE 102 or is intended to be a new C-SN configuration.

[0294] In some implementations, the MN 104A may also send the conditions associated with C-SN configuration 1 and the conditions associated with C-SN configuration 2, as well as C-SN configuration 1 and C-SN configuration 2, to the UE 102. In this implementation, the UE 102 replaces all existing conditions associated with the existing C-SN configuration with all received conditions associated with the received C-SN configuration. Therefore, the UE 102 does not need to determine whether the pre-existing conditions are associated with the received C-SN configuration.

[0295] Later, UE 102 determines 1160B that the conditions for accessing the second candidate cell are met, and in response, initiates 1166B a random access procedure on the second candidate cell. UE 102 then performs 1154B a random access procedure with C-SN 106A via the second candidate cell. Events 1148B, 1160B, 1166B, and 1154B occur at Figure 11B are collectively referred to as process 1192B.

[0296] exist Figure 11CIn example scenario 1100C, base station 104A operates as the MN for UE 102, and base station 106A operates as both the SN and C-SN for UE 102. Initially, UE 102 communicates 1108C with MN 104A and base station 106A, and either MN 104A or base station (as SN) 106A configures C-SN configuration 1 for a first candidate cell to UE 102. In scenario 1100C, it is assumed that UE 102 has not been configured with any other C-SN configuration prior to event 1108C, or that UE 102 has released any such previous configuration.

[0297] The base station 106A later determines 1111C to configure the C-SN configuration 2 of the second candidate cell for the UE 102 and, in response, generates 1138C the C-SN configuration 2 of the second candidate cell. The base station 106A then sends 1129C a message including the C-SN configuration 2 to the MN 104A.

[0298] In this implementation, in response to receiving the message including C-SN configuration 2, MN 104A generates a complete list or set of conditional configurations, which in this scenario 1100C includes only C-SN configuration 1 and C-SN configuration 2. MN 104A sends 1141C the complete set of conditional configurations (i.e., C-SN configuration 1 and C-SN configuration 2) to UE 102.

[0299] In some implementations, the MN 104A may also send the conditions associated with C-SN configuration 1 and the conditions associated with C-SN configuration 2, as well as C-SN configuration 1 and C-SN configuration 2, to the UE 102. In this implementation, the UE 102 replaces all existing conditions associated with the existing C-SN configuration with all received conditions associated with the received C-SN configuration. Therefore, the UE 102 does not need to determine whether the pre-existing conditions are associated with the received C-SN configuration.

[0300] In response to receiving the conditional configuration set, UE 102 replaces all stored C-SN configurations (here, only C-SN configuration 1) with the received C-SN configurations (i.e., C-SN configuration 1 and C-SN configuration 2), determines that the conditions for accessing the second candidate cell are met, and initializes and performs a random access procedure in process 1192C (e.g., similar to 1192B).

[0301] exist Figure 11DIn example scenario 1100D, base station 104A operates as the MN for UE 102, and base station 106A operates as both the SN and C-SN for UE 102. Initially, UE 102 communicates 1108D with MN 104A and base station (as SN) 106A, and either MN 104A or base station (as SN) 106A configures C-SN configuration 1 for a first candidate cell to UE 102. In scenario 1100D, it is assumed that UE 102 has not been configured with any other C-SN configuration prior to event 1108D, or that UE 102 has released any such previous configuration.

[0302] Base station 106A later determines 1111D to configure C-SN configuration 2 of the second candidate cell for UE 102, and in response, generates 1138D a complete list or set of conditional configurations, which in scenario 1100D includes only C-SN configuration 1 and C-SN configuration 2. Base station 106A sends 1137D the complete set of conditional configurations (i.e., C-SN configuration 1 and C-SN configuration 2) to UE 102 (e.g., via SRB3).

[0303] In some implementations, the base station 106A may also send the conditions associated with C-SN configuration 1 and the conditions associated with C-SN configuration 2, as well as C-SN configuration 1 and C-SN configuration 2, to the UE 102. In this implementation, the UE 102 replaces all existing conditions associated with the existing C-SN configuration with all received conditions associated with the received C-SN configuration. Therefore, the UE 102 does not need to determine whether the pre-existing conditions are associated with the received C-SN configuration.

[0304] In response to receiving the conditional configuration set, UE 102 replaces all stored C-SN configurations (here, only C-SN configuration 1) with the received C-SN configurations (i.e., C-SN configuration 1 and C-SN configuration 2), determines that the conditions for accessing the second candidate cell are met, and initializes and performs a random access procedure in process 1192D (e.g., similar to 1192B).

[0305] Figure 12 is a flow diagram illustrating an example method 1200 implemented in a user device (eg, UE 102) for maintaining a correct set of conditional configurations using configuration identifiers.

[0306] In method 1200, at block 1202, a user device receives a configuration and a configuration identifier from a base station (e.g., in any of transmissions 334A-C, 434A-B, 534A-C, 636A-B, 637C, 736A-B, 737C, 836A-B, 837C, 836D). The configuration is associated with conditions that must be met before the user device can use the configuration to communicate with a candidate base station (e.g., base station 106A) or via a candidate cell (e.g., cell 126A). For example, the configuration identifier can be a transaction ID, a cell ID, or a dedicated conditional configuration identifier.

[0307] At block 1204, the user device determines whether the configuration identifier corresponds to any pre-existing configuration stored in the user device. If not, the process proceeds to block 1206, where the user device stores the configuration as a new configuration in the user device. However, if the configuration identifier does correspond to a pre-existing configuration, at block 1208, the user device uses the received configuration to modify the pre-existing configuration. For example, blocks 1204, 1206, and 1208 may collectively correspond to any of events 340A-C, 440A-B, 540A-C, 642A-C, 742A-C, and 842A-D.

[0308] Figure 13 is a flow diagram illustrating an example method 1300 implemented in a RAN (eg, base station 104A and / or 106A) for utilizing configuration identifiers to facilitate maintaining a correct set of conditional configurations at a user device (eg, UE 102).

[0309] In the method 1300, at block 1302, the RAN (e.g., base station 104A or 106A) determines to configure a conditional procedure (e.g., conditional handover, conditional SN addition, or conditional SN change). For example, the determination at block 1302 may correspond to any one of determinations 310A-C, 410A-B, 510A-C, 612A-C, 712A-C, and 812A-D.

[0310] At block 1304, the RAN (e.g., base station 104A and / or 106A) assigns a configuration identifier (e.g., a transaction ID, a cell ID, a dedicated configuration identifier, etc.) to the configuration. For example, the assignment at block 1304 may correspond to any of events 320A-C, 420A-B, 520A-C, 620A-C, 720A-C, and 820A-D. Alternatively, the assignment at block 1304 in conjunction with subsequent identification of a configuration identifier corresponding to the first identifier (e.g., PCI) may correspond to an initial determination of the first identifier (e.g., CGI), such as described above in conjunction with Figure 4A 、 4B and 7A to 7C.

[0311] At block 1306, the RAN (e.g., base station 104A or 106A) causes the user device to store the configuration as a new configuration or use the configuration to modify a pre-existing configuration already stored at the user device based on the configuration identifier. Block 1306 includes the RAN sending the configuration identifier to the user device (e.g., sending any of 334A-C, 434A-B, 534A-C, 636A-B, 637C, 736A-B, 737C, 836A-B, 837C, 836D).

[0312] Figure 14 is a flow chart depicting an alternative example method 1400 implemented in a user device (eg, UE 102) of maintaining a correct set of condition configurations.

[0313] In method 1400, at block 1402, the user equipment receives (e.g., in any one of transmissions 1039A-B, 1137A, 1141B-C, 1137D) a conditional configuration set from the RAN (e.g., base station 104A). The set consists of one or more configurations, each corresponding to a specific type of conditional procedure (e.g., conditional handover, conditional SN addition, conditional SN addition or SN change, conditional SN addition or SN change via SRB3, conditional SN addition or SN change via SRB1, etc.).

[0314] At block 1404, the user device replaces all pre-existing conditional configurations corresponding to a particular type of conditional process with one or more configurations from the set of conditional configurations. For example, block 1404 may correspond to any of events 1045A-B or 1148A-B, or to a replacement occurring during process 1192C or 1192D.

[0315] Figure 15 is a flow chart depicting an alternative example method 1500 implemented in a RAN (eg, base station 104A and / or 106A) that facilitates maintaining a correct set of conditional configurations at a user device (eg, UE 102).

[0316] In method 1500, at box 1502, the RAN (e.g., base station 104A) maintains a conditional configuration set, which includes all unreleased conditional configurations associated with a specific user device and a specific type of conditional procedure (e.g., conditional handover, conditional SN add, conditional SN add or SN change, conditional SN add or SN change through SRB3, conditional SN add or SN change through SRB1, etc.).

[0317] At block 1504, the RAN (eg, base station 104A or 106A) determines to configure a conditional procedure (of the same specific type) for the user device. For example, block 1504 may correspond to any of events 1010A-B or 1111A-D.

[0318] At block 1506, the RAN (e.g., base station 104A) adds the first configuration to the set of conditional configurations. For example, block 1506 may include updating a memory in a base station of the RAN to add the first configuration.

[0319] At block 1508, the RAN (e.g., base station 104A or 106A) causes the user device to replace all pre-existing conditional configurations (corresponding to a particular type of conditional procedure) with all configurations in the conditional configuration set. Block 1508 includes the RAN sending the conditional configuration set to the user device (e.g., sending any of 1039A-B, 1137A, 1141B-C, 1137D).

[0320] By way of example and not limitation, the disclosure herein contemplates at least the following:

[0321] Aspect 1 - A method in a user device communicating with a base station, the method comprising: receiving, by processing hardware of the user device, from the base station (i) a configuration associated with a condition to be satisfied before the user device can use the configuration to communicate with a candidate base station or via a candidate cell and (ii) a configuration identifier; determining, by the processing hardware and based on the configuration identifier, whether the configuration corresponds to any pre-existing configuration stored in the user device; and (i) storing, by the processing hardware, the configuration as a new configuration in the user device or (ii) using the configuration to modify a pre-existing configuration stored in the user device based on whether the configuration corresponds to any pre-existing configuration stored in the user device.

[0322] Aspect 2 - The method of aspect 1, wherein: the condition is a condition to be satisfied before the user equipment can perform a handover to the candidate cell; and receiving the configuration includes receiving the configuration in a conditional handover command.

[0323] Aspect 3 - The method of aspect 2, wherein receiving the configuration identifier comprises receiving a transaction identifier or a measurement identifier in a conditional handover command.

[0324] Aspect 4 - The method according to aspect 2, wherein receiving the configuration identifier includes receiving a cell identifier of the candidate cell in a conditional handover command.

[0325] Aspect 5 - The method of aspect 4, wherein receiving the cell identifier comprises receiving a physical cell identifier (PCI) of the candidate cell in a conditional handover command.

[0326] Aspect 6 - The method according to aspect 2, wherein receiving the configuration identifier comprises (i) receiving the configuration identifier in an information element of a conditional handover command dedicated to the configuration identifier or (ii) receiving the configuration identifier in a message of a radio resource control (RRC) container that separately includes the conditional handover command.

[0327] Aspect 7 - The method of aspect 2, wherein: receiving the configuration and configuration identifier from the base station comprises receiving the configuration and configuration identifier from a first distributed unit of the base station; and the candidate cell is associated with a second distributed unit of the base station.

[0328] Aspect 8 - The method according to aspect 2, wherein the candidate cells are associated with different base stations.

[0329] Aspect 9 - A method according to Aspect 1, wherein: the condition is a condition to be satisfied before the user device is able to add the candidate base station as an auxiliary node to operate with dual connectivity with the base station and the candidate base station; and the method includes receiving at least the configuration in a conditional auxiliary node configuration message from the base station.

[0330] Aspect 10 - The method of aspect 9, wherein receiving the configuration identifier comprises receiving a transaction identifier or a measurement identifier in a conditional assisting node configuration message.

[0331] Aspect 11 - The method of aspect 9, wherein receiving the configuration identifier comprises receiving a cell identifier of a cell associated with the candidate base station in a conditional assisting node configuration message.

[0332] Aspect 12—The method of aspect 9, wherein receiving the configuration identifier comprises (i) receiving the configuration identifier in an information element of a conditional assisting node configuration message dedicated to the configuration identifier or (ii) receiving the configuration identifier in a message of a radio resource control (RRC) container that separately includes the conditional assisting node configuration message.

[0333] Aspect 13 - The method according to aspect 9, comprising: receiving the configuration and the configuration identifier from the base station when the base station operates as a master node with which the user device operates in dual connectivity.

[0334] Aspect 14 - The method of aspect 9, comprising: receiving the configuration and the configuration identifier from the base station when the base station operates as an assisting node with which the user device operates in dual connectivity.

[0335] Aspect 15 - The method according to aspect 1, further comprising: determining, by processing hardware, that a condition is satisfied; and in response to determining that the condition is satisfied, performing a random access procedure to communicate with the candidate base station or a base station associated with the candidate cell.

[0336] Aspect 16 - The method according to aspect 1, further comprising: receiving a configuration release message including a configuration identifier from the base station or a different base station; and releasing the configuration by the processing hardware in response to receiving the configuration release message.

[0337] Aspect 17 - A method in a user device configured to store configurations for communicating with a candidate base station or communicating via a candidate cell, the method comprising: receiving, by processing hardware of the user device, a conditional configuration set consisting of one or more configurations from a radio access network (RAN), each of the one or more configurations being associated with (i) a corresponding candidate base station or a corresponding candidate cell and (ii) a corresponding condition to be satisfied before the user device can communicate with the corresponding candidate base station or communicate via the corresponding candidate cell according to a first type of conditional procedure; and in response to receiving the conditional configuration set, replacing (i) all pre-existing configurations stored in the user device and associated with the condition to be satisfied before the user device can communicate with a particular candidate base station or communicate via a particular candidate cell according to the first type of conditional procedure with (ii) one or more configurations in the conditional configuration set, regardless of whether any configuration in the conditional configuration set corresponds to any pre-existing configuration.

[0338] Aspect 18 - A method according to Aspect 17, wherein: the first type of conditional procedure is a conditional handover procedure; for each of the one or more configurations, the corresponding condition is a condition to be satisfied before the user device can perform a handover to the corresponding candidate cell; and receiving the set of conditional configurations includes receiving one or more conditional handover commands from the RAN.

[0339] Aspect 19 - A method according to Aspect 17, wherein: the first type of conditional procedure is a conditional auxiliary node addition procedure; for each of one or more configurations, the corresponding condition is a condition to be met before the user device is able to add the corresponding candidate base station as an auxiliary node to operate with dual connectivity with the primary node and the auxiliary node; and receiving the conditional configuration set includes receiving one or more conditional auxiliary node configuration messages from the RAN.

[0340] Aspect 20 - The method according to Aspect 19, comprising: receiving the conditional configuration set from a base station operating as a master node.

[0341] Aspect 21 - The method according to Aspect 19, comprising: receiving a conditional configuration set from a base station operating as a current assisting node.

[0342] Aspect 22 - The method according to Aspect 17 further includes: determining, by processing hardware, that a first condition associated with one of the one or more configurations is satisfied; and in response to determining that the first condition is satisfied, performing a random access procedure to communicate with a candidate base station corresponding to the first condition or via a candidate cell corresponding to the first condition.

[0343] Aspect 23—The method of Aspect 17, wherein replacing all pre-existing configurations with one or more configurations in the conditional configuration set comprises: for a first pre-existing configuration comprising a plurality of configuration parameters, replacing only a subset of the plurality of configuration parameters.

[0344] Aspect 24 - The method according to aspect 1, wherein the first type of conditional procedure is a procedure in which the base station configures the user equipment via one or more specific types of signaling radio bearers (SRBs).

[0345] Aspect 25 - A user device comprising hardware and configured to perform the method according to any one of aspects 1 to 24.

[0346] Aspect 26 - A method in a radio access network (RAN), the method comprising: determining, by processing hardware of the RAN, a configuration conditional procedure that enables a user device to conditionally communicate with a candidate base station of the RAN or communicate via a candidate cell of the RAN; assigning, by the processing hardware, a configuration identifier to a configuration associated with (i) the candidate base station or candidate cell and (ii) a condition to be satisfied before the user device can use the configuration to communicate with the candidate base station or communicate via the candidate cell; and causing the user device to, based on at least the configuration identifier, (i) store the configuration as a new configuration or (ii) use the configuration to modify a pre-existing configuration stored at the user device.

[0347] Aspect 27 - The method according to Aspect 26, wherein the process enables the user equipment to conditionally hand over to the candidate cell.

[0348] Aspect 28 - The method of Aspect 27, wherein assigning a configuration identifier to the configuration comprises assigning a transaction identifier or a measurement identifier to the configuration.

[0349] Aspect 29 - The method according to Aspect 27, wherein assigning the configuration identifier to the configuration comprises assigning a cell identifier of a candidate cell to the configuration.

[0350] Aspect 30—A method according to Aspect 27, wherein assigning the cell identifier to the configuration comprises: determining, at a first base station of the RAN, a cell global identifier (CGI) of the candidate cell; and determining, at a base station corresponding to the candidate cell, a physical cell identifier (PCI) corresponding to the CGI, wherein sending the configuration identifier to the user device comprises sending, by the base station corresponding to the candidate cell, the PCI of the candidate cell to the user device.

[0351] Aspect 31 - A method according to aspect 27, wherein assigning the configuration identifier to the configuration comprises assigning (i) a value of an information element in a conditional handover command dedicated to the configuration identifier or (ii) a value in a message of a radio resource control (RRC) container that separately includes the conditional handover command.

[0352] Aspect 32 - The method of aspect 27, wherein: determining the configuration process is performed at a first base station of the RAN; sending the configuration and the configuration identifier to the user device is performed by the first base station; and the candidate cell is associated with a second base station of the RAN.

[0353] Aspect 33 - A method according to Aspect 32, wherein: assigning a configuration identifier to the configuration is performed at the first base station; the method also includes sending a handover request including the configuration identifier by the first base station to the second base station; and the method also includes sending a handover request confirmation including the configuration by the second base station to the first base station.

[0354] Aspect 34 - A method according to Aspect 32, wherein: the method further comprises sending a handover request by the first base station to the second base station; assigning a configuration identifier to the configuration is performed at the second base station; and the method further comprises sending a handover request confirmation including the configuration and the configuration identifier by the second base station to the first base station.

[0355] Aspect 35 - The method of aspect 27, wherein: determining the configuration process is performed at a first base station of the RAN; sending the configuration and the configuration identifier to the user device is performed by the first base station; and the first candidate cell is associated with the first base station.

[0356] Aspect 36 - The method of aspect 26, wherein the process enables the user device to conditionally add a candidate base station as a secondary node to operate in dual connectivity with the primary node and the secondary node.

[0357] Aspect 37—The method according to Aspect 36, wherein assigning a configuration identifier to the configuration comprises assigning a transaction identifier or a measurement identifier to the configuration.

[0358] Aspect 38 - The method of Aspect 36, wherein assigning the configuration identifier to the configuration comprises assigning a cell identifier of a cell associated with the candidate base station to the configuration.

[0359] Aspect 39 - A method according to Aspect 36, wherein assigning a cell identifier to the configuration comprises: determining, at a first base station of the RAN, a cell global identifier (CGI) of a cell associated with the candidate base station; and determining, at the candidate base station, a physical cell identifier (PCI) corresponding to the CGI, wherein sending the configuration identifier to the user device comprises sending the PCI of the candidate cell to the user device.

[0360] Aspect 40—A method according to aspect 36, wherein assigning the configuration identifier to the configuration comprises assigning (i) a value of an information element of a conditional assisting node configuration message dedicated to the configuration identifier or (ii) a value in a message of a radio resource control (RRC) container that separately includes the assisting node configuration message.

[0361] Aspect 41 - The method of Aspect 36, wherein: determining the configuration process is performed at a first base station of the RAN; and sending the configuration and the configuration identifier to the user device is performed by the first base station.

[0362] Aspect 42 - A method according to Aspect 41, wherein: assigning a configuration identifier to a configuration is performed at a first base station; the method further comprises sending, by the first base station, an auxiliary node add or change request including the configuration identifier to a candidate base station; and the method further comprises sending, by the candidate base station, an auxiliary node add or change request including the configuration to the first base station.

[0363] Aspect 43 - A method according to Aspect 41, wherein: the method also includes sending an auxiliary node add or change request by the first base station to the candidate base station; assigning a configuration identifier to the configuration is performed at the candidate base station; and the method also includes sending an auxiliary node add or change request confirmation including the configuration and the configuration identifier by the candidate base station to the first base station.

[0364] Aspect 44 - The method of aspect 36, wherein determining the configuration procedure and assigning the configuration identifier to the configuration is performed at a first base station of the RAN operating as a current assisting node.

[0365] Aspect 45 - The method according to Aspect 44, wherein: the method further comprises sending, by the first base station, the configuration and the configuration identifier to a second base station of the RAN operating as a master node; and sending the configuration and the configuration identifier to the user device is performed by the second base station.

[0366] Aspect 46 - The method of Aspect 44, wherein sending the configuration and the configuration identifier to the user equipment is performed at the first base station.

[0367] Aspect 47 - The method according to Aspect 26, further comprising: causing the user device to release the configuration at least by sending a configuration release message including the configuration identifier to the user device.

[0368] Aspect 47 - A method in a radio access network (RAN), the method comprising maintaining, by processing hardware of the RAN, a set of conditional configurations, the set comprising all unreleased configurations associated with (i) a user device and (ii) a condition to be satisfied before the user device can communicate with a corresponding candidate base station or via a corresponding candidate cell according to a first type of conditional procedure; determining, by the processing hardware, to configure a first conditional procedure of a first type, the first conditional procedure enabling the user device to conditionally communicate with a first candidate base station of the RAN or via a first candidate cell of the RAN; adding, by the processing hardware, a first configuration to the set of conditional configurations, the first configuration associated with (i) the first candidate base station or the first candidate cell and (ii) the condition to be satisfied before the user device can communicate with the first candidate base station or via the first candidate cell using the first configuration and according to the first type of conditional procedure; and, after adding the first configuration, causing the user device to replace (i) all pre-existing configurations stored in the user device and associated with the condition to be satisfied before the user device can communicate with a particular candidate base station or via a particular candidate cell according to the first type of conditional procedure with (ii) all configurations in the set of conditional configurations, at least by sending the set of conditional configurations to the user device.

[0369] Aspect 49 - A method according to Aspect 48, wherein: the first type of conditional procedure is a conditional handover procedure; the first conditional procedure enables the user device to conditionally handover to the first candidate cell; determining to configure the first conditional procedure, adding the first configuration to a conditional configuration set, and sending the conditional configuration set to the user device are performed at a first base station of the RAN.

[0370] Aspect 50 - The method according to aspect 49, further comprising: sending, by the first base station, a handover request to a second base station of the RAN associated with the first candidate cell; and sending, by the second base station, a handover request confirmation including the first configuration to the first base station.

[0371] Aspect 51 - The method according to Aspect 49, wherein the first candidate cell is associated with the first base station.

[0372] Aspect 52—The method according to Aspect 48, wherein: the first type of conditional procedure is a conditional secondary node addition procedure; and the first conditional procedure enables the user device to conditionally add the first candidate base station as a secondary node to operate with dual connectivity with the primary node and the secondary node.

[0373] Aspect 53 - A method according to Aspect 52, wherein: determining the configuration of the first conditional process is performed at a first base station of the RAN operating as a master node; the method also includes sending a conditional auxiliary node addition request by the first base station to a first candidate base station; the method also includes sending a conditional auxiliary node addition request confirmation including the first configuration by the first candidate base station to the first base station; adding the first configuration to the conditional configuration set is performed at the first base station; and sending the conditional configuration to the user device is performed by the first base station.

[0374] Aspect 54 - A method according to Aspect 52, wherein: determining the configuration first condition process is performed at a first base station of the RAN operating as a current auxiliary node; the method also includes sending the first configuration by the first base station to a second base station of the RAN operating as a primary node; adding the first configuration to the conditional configuration set is performed at the second base station; and sending the conditional configuration set to the user device is performed by the second base station.

[0375] Aspect 55 - A method according to Aspect 52, wherein: determining the configuration first condition process is performed at a first base station of the RAN operating as a current auxiliary node; adding the first configuration to the conditional configuration set is performed at the first base station; and sending the conditional configuration set to the user device is performed by the first base station.

[0376] Aspect 56 - The method according to aspect 48 further includes: determining, by the processing hardware, to release the first configuration; in response to determining to release the first configuration, removing, by the processing hardware, the first configuration from the conditional configuration set; and after removing the first configuration, sending the conditional configuration set to the user device.

[0377] Aspect 57 - The method according to aspect 48, wherein the first type of conditional procedure is a procedure in which the RAN configures the user equipment via one or more specific types of signaling radio bearers (SRBs).

[0378] Aspect 58 - A radio access network (RAN) comprising hardware and configured to perform a method according to any one of aspects 26 to 57.

[0379] In the above description, the terms "conditional SN addition / change" and "conditional PSCell addition / change" may be used interchangeably. For example, the conditional configuration may be a CHO command or a C-SN configuration.

[0380] The user device (e.g., UE 102) that can implement the technology of the present disclosure can be any suitable device capable of wireless communication, such as a smartphone, tablet computer, laptop computer, mobile game console, point of sale (POS) terminal, health monitoring device, drone, camera, media streaming dongle or another personal media device, wearable device such as smart watch, wireless hotspot, femtocell or broadband router. In addition, in some cases, the user device can be embedded in an electronic system, such as the main unit of a vehicle or an advanced driver assistance system (ADAS). In addition, the user device can operate as an Internet of Things (IoT) device or a mobile Internet device (MID). Depending on the type, the user device may include one or more general-purpose processors, a computer-readable memory, a user interface, one or more network interfaces, one or more sensors, etc.

[0381] Certain embodiments are described in this disclosure as including logic or multiple components or modules. A module can be a software module (e.g., code or machine-readable instructions stored on a non-transitory machine-readable medium) or a hardware module. A hardware module is a tangible unit that is capable of performing certain operations and can be configured or arranged in a certain manner. A hardware module can include permanently configured dedicated circuitry or logic (e.g., as a dedicated processor, such as a field programmable gate array (FPGA) or application-specific integrated circuit (ASIC), a digital signal processor (DSP), etc.) to perform certain operations. A hardware module can also include programmable logic or circuitry (e.g., contained within a general-purpose processor or other programmable processor) that is temporarily configured by software to perform certain operations. The decision to implement a hardware module in a dedicated and permanently configured circuitry or in a temporarily configured circuitry (e.g., configured by software) can be driven by cost and time considerations.

[0382] When implemented in software, the techniques may be provided as part of an operating system, in a library used by multiple applications, in 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 performed by a user device communicating with a base station, the method comprising: receiving from the base station (i) the configuration associated with conditions to be satisfied before the user device can communicate with a candidate base station or via a candidate cell using the configuration and (ii) a dedicated configuration identifier specifically for identifying the configuration; storing the configuration as a new configuration in the user device when the dedicated configuration identifier does not correspond to any pre-existing configuration stored in the user device; as well as When the dedicated configuration identifier corresponds to a pre-existing configuration stored in the user device, the pre-existing configuration stored in the user device is modified using the configuration.

2. The method according to claim 1, wherein: The condition is a condition to be satisfied before the user equipment can perform handover to the candidate cell; as well as Receiving the configuration includes receiving the configuration in a conditional switch command.

3. The method according to claim 2, wherein: Receiving the dedicated configuration identifier includes receiving the dedicated configuration identifier in an information element of the conditional handover command.

4. The method according to claim 2, wherein: Receiving the dedicated configuration identifier includes receiving the dedicated configuration identifier in a message of a radio resource control (RRC) container that solely includes the conditional handover command.

5. The method according to claim 2, wherein: Receiving the configuration and the dedicated configuration identifier from the base station comprises receiving the configuration and the dedicated configuration identifier from a first distributed unit of the base station; and The candidate cell is associated with a second distributed unit of the base station.

6. The method according to claim 1, wherein: The condition is a condition to be satisfied before the user device can add the candidate base station as an auxiliary node to operate with dual connectivity with the base station and the candidate base station; as well as The method comprises receiving at least the configuration in a conditional assisting node configuration message from the base station.

7. The method according to claim 6, wherein: Receiving the dedicated configuration identifier includes receiving the dedicated configuration identifier in an information element of the conditional assisting node configuration message.

8. The method according to claim 6, wherein: Receiving the dedicated configuration identifier includes receiving the dedicated configuration identifier in a message of a radio resource control (RRC) container that solely includes the conditional assisting node configuration message.

9. The method according to claim 6, comprising: When the base station operates as a master node, the configuration and the dedicated configuration identifier are received from the base station, and the user device operates with the master node in dual connectivity.

10. The method according to claim 6, comprising: The configuration and the dedicated configuration identifier are received from the base station when the base station operates as an assisting node, and the user device operates with the assisting node in dual connectivity.

11. The method according to any one of claims 1 to 10, further comprising: When the condition is satisfied, a random access procedure is performed to communicate with the candidate base station or a base station associated with the candidate cell.

12. The method according to claim 1, further comprising: receiving a configuration release message including the dedicated configuration identifier from the base station or a different base station; as well as In response to receiving the configuration release message including the dedicated configuration identifier, the configuration is released.

13. The method of any one of claims 1 to 10, wherein modifying a pre-existing configuration using the configuration comprises: At least a portion of a pre-existing configuration is replaced with the configuration associated with the condition to be satisfied.

14. The method according to any one of claims 1 to 10, wherein storing the configuration as a new configuration at the user device occurs when the dedicated configuration identifier is different from a pre-existing configuration stored at the user device; and Modifying a pre-existing configuration stored in the user device using the configuration occurs when the dedicated configuration identifier is not different from a pre-existing configuration stored in the user device.

15. A user device comprising hardware and configured to perform the method according to any one of claims 1 to 14.

16. A method performed by a Radio Access Network (RAN), the method comprising: assigning a dedicated configuration identifier to a configuration associated with (i) the candidate base station or the candidate cell in a conditional process for enabling a user device to conditionally communicate with the candidate base station of the RAN or the candidate cell of the RAN and (ii) a condition to be satisfied before the user device can communicate with the candidate base station or via the candidate cell using the configuration; as well as The configuration and the dedicated configuration identifier are sent to the user device, instructing the user device to (i) store the configuration as a new configuration when the dedicated configuration identifier does not correspond to any pre-existing configuration stored in the user device and (ii) modify the pre-existing configuration stored in the user device using the configuration when the dedicated configuration identifier corresponds to a pre-existing configuration stored in the user device.

17. The method according to claim 16, wherein The conditional process enables the user device to conditionally handover to the candidate cell.

18. The method according to claim 17, wherein Assigning the dedicated configuration identifier to the configuration comprises assigning a value of an information element in a conditional handover command.

19. The method according to claim 17, wherein Assigning the dedicated configuration identifier to the configuration comprises assigning a value in a message of a Radio Resource Control (RRC) container comprising solely the conditional handover command.

20. The method according to claim 17, wherein Sending the configuration and the dedicated configuration identifier to the user device is performed by a first base station of the RAN; and The candidate cell is associated with the first base station.

21. The method of claim 17, wherein: Sending the configuration and the dedicated configuration identifier to the user equipment is performed by a first base station of the RAN; and The candidate cell is associated with a second base station of the RAN.

22. The method of claim 21, wherein: assigning the dedicated configuration identifier to the configuration is performed at the first base station; The method further includes sending, by the first base station to the second base station, a handover request including the dedicated configuration identifier; and The method further includes sending, by the second base station to the first base station, a handover request confirmation including the configuration.

23. The method of claim 21, wherein: The method further includes sending, by the first base station, a handover request to the second base station; assigning the dedicated configuration identifier to the configuration is performed at the second base station; and The method further includes sending, by the second base station to the first base station, a handover request acknowledgement including the configuration and the dedicated configuration identifier.

24. The method according to claim 16, wherein The conditional process enables the user device to conditionally add the candidate base station as a secondary node to operate in dual connectivity with a primary node and the secondary node.

25. The method according to claim 24, wherein Assigning the dedicated configuration identifier to the configuration comprises any of the following: (i) assigning a value to an information element of a conditional assistance node configuration message; or (ii) allocating a value in a message of a Radio Resource Control (RRC) container that separately includes the assisting node configuration message.

26. The method of claim 24, wherein: assigning the dedicated configuration identifier to the configuration is performed at a first base station; performing, at the first base station, transmitting the configuration and the dedicated configuration identifier to the user device; The method further includes sending, by the first base station to the candidate base station, an assisting node add or change request including the dedicated configuration identifier; and The method further includes sending, by the candidate base station to the first base station, an auxiliary node addition or change request confirmation including the configuration.

27. The method of claim 24, wherein: The first base station sends the configuration and the dedicated configuration identifier to the user equipment; The method further includes sending, by the first base station, an auxiliary node addition or change request to the candidate base station; assigning the dedicated configuration identifier to the configuration is performed at the candidate base station; and The method further includes sending, by the candidate base station to the first base station, an auxiliary node add or change request confirmation including the configuration and the dedicated configuration identifier.

28. The method according to claim 24, wherein assigning the dedicated configuration identifier to the configuration is performed at a first base station of the RAN operating as a current assisting node; The method further comprises sending, by the first base station, the configuration and the dedicated configuration identifier to a second base station of the RAN operating as a master node; as well as The sending of the configuration and the dedicated configuration identifier to the user equipment is performed by the second base station.

29. The method according to claim 24, wherein assigning the dedicated configuration identifier to the configuration is performed at a first base station of the RAN operating as a current assisting node; as well as Sending the configuration and the dedicated configuration identifier to the user equipment is performed by the first base station.

30. The method of claim 29, further comprising: A configuration release message including the dedicated configuration identifier is sent to the user device, instructing the user device to release the configuration.

31. The method according to any one of claims 16 to 30, wherein: Sending the configuration and the dedicated configuration identifier to the user device instructs the user device to (i) store the configuration as a new configuration when the dedicated configuration identifier is different from any pre-existing configuration stored in the user device and (ii) modify the pre-existing configuration already stored in the user device using the configuration when the dedicated configuration identifier is not different from the pre-existing configuration stored in the user device.

32. A radio access network comprising hardware and configured to perform the method according to any one of claims 16 to 31.

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