Method and apparatus for managing UE preferred configurations

Abstract

To manage a preferred configuration indicating a maximum allocation preferred by a UE for at least one resource, the UE sends (802A) the preferred configuration to the RAN, transitions (804A) to a state where the radio connection between the UE and the RAN is suspended, and releases (806A) the preferred configuration before communicating data over the radio connection.

Description

Technical Field

[0001] The present invention generally relates to wireless communication, and more particularly, to managing UE preferred configurations. Background Art

[0002] The purpose of providing this background description is to generally introduce the background of the present invention. As to the scope of what is described in this background section, the work of the currently named inventors, as well as aspects of the descriptions that may not qualify as prior art at the time of application, are neither expressly nor implicitly regarded as prior art against the present invention.

[0003] In some cases, a user equipment (or user device, commonly abbreviated as "UE" for short) may simultaneously use resources of multiple network nodes, such as base stations, interconnected through a backhaul. These network nodes may support the same RAT or different RATs, and when supporting different RATs, this type of connectivity is generally referred to as DC, especially MR-DC. When the UE operates in DC, one base station operates as a master node (MN), and another base station operates as a secondary node (SN). For example, the backhaul may support the X2 or XN interface.

[0004] The MN can provide a control plane connection and a user plane connection to the core network (CN), while the SN generally provides a user plane connection. The cell associated with the MN defines the master cell group (MCG), and the cell associated with the SN defines the secondary cell group (SCG). The UE and the base stations MN and SN can use signaling radio bearers (SRBs) to exchange radio resource control (RRC) messages as well as non-access stratum (NAS) messages.

[0005] The UE can use several types of SRBs when operating in DC. SRB1 and SRB2 resources allow the UE and the MN to exchange RRC messages related to the MN and embed RRC messages related to the SN, and can be referred to as MCG SRBs. SRB3 resources allow the UE and the SN to exchange RRC messages related to the SN, and can be referred to as SCG SRBs. Split SRBs allow the UE to directly exchange RRC messages with the MN by using the radio resources of the MN, the SN, or both the MN and the SN. In addition, the UE and the base stations (such as the MN and the SN) use data radio bearers (DRBs) to transmit data on the user plane. A DRB terminated at the MN but only using the lower-layer resources of the MN can be referred to as an MCG DRB, a DRB terminated at the SN but only using the lower-layer resources of the SN can be referred to as an SCG DRB; a DRB terminated at the MCG but using the lower-layer resources of both the MN and the SN can be referred to as a split DRB.

[0006] In some cases, a base station (e.g., MN, SN) and / or the CN may cause the UE to transition from one state of the Radio Resource Control (RRC) protocol to another. More specifically, the UE may operate in an idle state (e.g., EUTRA-RRC_IDLE, NR-RRC IDLE), where the UE does not have a radio connection with the base station and does not have a pending RRC connection with the base station; a connected state (e.g., EUTRA-RRC_CONNECTED, NR-RRC CONNECTED), where the UE has a radio connection with the base station; or an inactive state (e.g., EUTRA-RRC INACTIVE, NR-RRC INACTIVE), where the UE has a pending radio connection with the base station.

[0007] In some implementations and scenarios, the UE may operate in the connected state and then transition to the inactive state or the idle state. In response to a network-triggered event, such as when the base station paging the UE (e.g., for an incoming phone call), or when the UE is triggered to send data (e.g., an outgoing phone call, browser launch), the UE may transition back to the connected state. To make the transition, the UE may request the base station to resume the pending radio connection (e.g., by sending an RRC resume request message) so that the base station can configure the UE to operate in the connected state again.

[0008] 3GPP TS 36.331 and 38.331 describe the procedures for handling the UE's preferred configuration. These procedures involve the UE sending the preferred configuration to the MN via the UEAssistanceInformation message in the connected state. When sending the preferred configuration, when the UE encounters an overheating situation (e.g., due to heavy application process handling or high ambient temperature), the UE is able to suggest to the MN to temporarily adjust the number of SCell, the number of MIMO layers, and / or the aggregated bandwidth used during the connected state. For example, if the UE and the MN are configured to communicate via the maximum number of SCell, the maximum number of MIMO layers, and / or the maximum aggregated bandwidth, the UE can suggest to the MN to reduce the maximum number of SCell, the maximum number of MIMO layers, and / or the minimum aggregated bandwidth by sending the preferred configuration to the MN. The preferred configuration indicates the preferred maximum number of SCell, the preferred maximum number of MIMO layers, and / or the preferred maximum aggregated bandwidth. Therefore, the preferred configuration represents the maximum allocation of one or more resources preferred by the UE.

[0009] However, when the UE transitions from the connected state to the inactive state, it is not clear how to handle the UE preferred configuration. In addition, in a scenario where the UE is in a DC with the MN and the SN, the UE can indicate, in the UE preferred configuration, the preferred maximum number of SCell, the preferred maximum number of MIMO layers, and / or the preferred maximum aggregated bandwidth specifically for the SN. However, if the SN is a distributed base station including a CU and a DU, it is not clear how the CU and the DU handle the UE preferred configuration. In addition, if the SN does not support the UE Assistance Information message, the SN may not be able to confirm the UE preferred configuration, resulting in the MN not wishing to restore the UE to single connectivity (SC) with the MN. Summary of the Invention

[0010] The base station and UE implementations of the present disclosure enable techniques for the base station and the UE to at least temporarily release or retain the UE preferred configuration when the UE transitions from the connected state to the inactive state. In addition, if the base station is a distributed SN including a CU and a DU, the DU can receive the UE preferred configuration from the CU via an interface message. In addition, in a case where the UE is in a DC connection with the MN and a legacy SN that does not support the UE Assistance Information message to interpret the UE preferred configuration included in the UE Assistance Information message, the MN can convert the UE Assistance Information message into a format readable by the SN, so that the SN can correctly interpret the UE preferred configuration.

[0011] Exemplary embodiments of these techniques are a method in a UE for managing a preferred configuration indicating a preferred maximum allocation of the UE to at least one resource. The method is implemented using processing hardware and includes sending the preferred configuration to the RAN; transitioning to the inactive state, where the radio connection between the UE and the RAN is suspended; and releasing the preferred configuration before communicating data via the radio connection.

[0012] Another example embodiment of these techniques is a method in the DU of a non-aggregated base station including a DU and a central unit CU. The method is implemented using processing hardware and includes receiving from the CU a preferred configuration indicating a preferred maximum allocation of the UE to at least one resource; generating a DU configuration of the UE using the preferred configuration; and sending the CU and DU configurations.

[0013] Another exemplary embodiment of these techniques is a method in the CU of a non-aggregated base station including a CU and a DU. The method is implemented using processing hardware and includes receiving a preferred configuration indicating the maximum preferred allocation of the UE to at least one resource; and sending an indication of the maximum preferred allocation of the UE to the DU.

[0014] Another exemplary embodiment of these techniques is a method for managing the configuration of a secondary node (SN) in a master node (MN) when a user equipment (UE) operates in dual connectivity (DC) with the MN and the SN. The method may be implemented using processing hardware and includes determining, using the capabilities of at least one of the UE or the SN, whether the SN will receive an indication of a maximum allocation preferred by the UE for at least one resource; and providing the indication to the SN in response to determining that the SN will receive the indication.

[0015] Another exemplary embodiment of these techniques is a method for managing a preferred configuration indicating a maximum allocation preferred by a UE for at least one resource in the UE, where the UE operates in DC with an MN and an SN. The method may be implemented by processing hardware and includes sending the preferred configuration to the MN or the SN; receiving an indication that the SN will be released; disconnecting from the SN in response to the indication; and releasing the preferred configuration.

[0016] Another exemplary embodiment of these techniques is a method for managing a preferred configuration indicating a maximum allocation preferred by a UE for at least one resource in the UE, where the UE operates in DC with an MN and a first SN. The method may be implemented by processing hardware and includes sending a first preferred configuration to the first SN; receiving mobility information of a second secondary cell group (SCG) of a second SN from the MN before the first SN successfully receives the first preferred configuration; and determining whether to send a second preferred configuration to the first SN or the second SN based on the mobility information.

[0017] Another embodiment of these techniques is a base station including processing hardware and configured to implement one of the above methods.

[0018] Another embodiment of these techniques is a UE including processing hardware and configured to implement one of the above methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1A and Figure 1B are block diagrams of example systems in which a radio access network (RAN) and a UE may implement the techniques of the present invention for managing UE preferred configurations;

[0020] Figure 1C is Figure 1A or Figure 1B a block diagram of an example base station that may operate in a

[0021] Figure 2 is a block diagram of an example protocol stack according to which a Figure 1A or Figure 1B UE may communicate with a Figure 1A or Figure 1B base station;

[0022] Figure 3AIt is a messaging diagram of an example scenario where the UE releases the preferred configuration after suspending the radio connection with the base station;

[0023] Figure 3B It is a messaging diagram of an example scenario where the UE retains the preferred configuration after suspending the radio connection with the base station and then overwrites the preferred configuration with a new preferred configuration when resuming the radio connection;

[0024] Figure 3C It is a messaging diagram of an example scenario where the UE releases the preferred configuration before suspending the radio connection with the base station;

[0025] Figure 4A It is a messaging diagram of an example scenario where the central unit (CU) of a non-aggregated base station receives the preferred configuration of the UE and sends the preferred configuration to the distributed unit (DU) of the non-aggregated base station;

[0026] Figure 4B It is a messaging diagram of an example scenario where the CU of a non-aggregated base station receives the preferred configuration of the UE and releases the preferred configuration;

[0027] Figure 5A It is a messaging diagram of an example scenario where the UE provides the preferred configuration to the secondary node (SN) through the master node (MN) and then releases the preferred configuration when disconnecting from the SN;

[0028] Figure 5B It is related to Figure 5A A messaging diagram of a scenario similar to the scenario, but the SN directly provides the DU configuration to the UE through the radio interface;

[0029] Figure 5C It is a messaging diagram of an example scenario where the SN initiates the SN release process due to the preferred configuration of the UE, and the UE releases the preferred configuration in response to the initiation of the SN release process;

[0030] Figure 5D It is a messaging diagram of an example scenario where the UE retains the preferred configuration until the UE generates a new preferred configuration in response to the initiation of the SN release process;

[0031] Figure 5E It is a messaging diagram of an example scenario where the SN initiates the SN release process due to the preferred configuration of the UE, but the UE retains the preferred configuration until the UE generates a new preferred configuration in response to the initiation of the SN release process;

[0032] Figure 5F It is a messaging diagram of an example scenario where the MN formats the preferred configuration so that the SN can process the preferred configuration;

[0033] Figure 5GIt is a messaging diagram of an example scenario, where the MN determines to release the SN in response to receiving a preferred configuration from the SN;

[0034] Figure 6A It is a messaging diagram of an example scenario, where the UE retains the preferred configuration until the UE generates a new preferred configuration in response to an indication received from the MN to suspend the radio connection with the RAN;

[0035] Figure 6B It is a messaging diagram of an example scenario, where the UE releases the preferred configuration after receiving an indication from the MN to suspend the radio connection with the SN;

[0036] Figure 6C It is a messaging diagram of an example scenario, where the UE releases the preferred configuration after receiving an indication from the MN to suspend the radio connection with a legacy SN;

[0037] Figure 7 It is a messaging diagram of an example scenario, where the MN forwards the preferred configuration from the source SN to the target SN during the SN change process;

[0038] Figure 8A It is a flowchart of an example method that includes releasing the preferred configuration when the radio connection is suspended, which can be implemented in the UE of Figure 1A and Figure 1B ;

[0039] Figure 8B It is a flowchart of an example method that includes releasing the preferred configuration when resuming a previously suspended radio connection, which can be implemented in the UE of Figure 1A and Figure 1B ;

[0040] Figure 9 It is a flowchart of an example method that includes releasing the preferred configuration when generating a new preferred configuration, which can be implemented in the UE of Figure 1A and Figure 1B ;

[0041] Figure 10A It is a flowchart of an example method that includes releasing the preferred configuration when disconnecting from the SN, which can be implemented in the UE of Figure 1A and Figure 1B ;

[0042] Figure 10B It is a flowchart of an example method that includes releasing the preferred configuration in response to a configuration of the SN, which can be implemented in the UE of Figure 1A and Figure 1B ;

[0043] Figure 11 It is a flowchart of an example method that includes releasing the preferred configuration when generating a new preferred configuration, which can be implemented in the UE of Figure 1A andFigure 1B implemented in the UE;

[0044] Figure 12A is a flowchart of an example method for determining whether a UE should send a preferred configuration to an SN and can be implemented in the Figure 1A and Figure 1B MN;

[0045] Figure 12B is a flowchart of an example method for determining whether an MN should send a preferred configuration to an SN and can be implemented in the Figure 1A and Figure 1B MN;

[0046] Figure 12C is a flowchart of an example method that describes determining whether to generate a DU configuration using a UE preferred configuration received from an MN and can be implemented in the Figure 1A and Figure 1B SN;

[0047] Figure 13 is a flowchart of an example method for processing a UE preferred configuration and can be implemented in the CU of a non - aggregated base station in Figure 1A and Figure 1B ;

[0048] Figure 14A is a flowchart of an example method for analyzing a UE preferred configuration and can be implemented in the Figure 1A and Figure 1B MN;

[0049] Figure 14B is a flowchart of an example method for analyzing a UE preferred configuration and can be implemented in the Figure 1A and Figure 1B SN;

[0050] Figure 15 is a flowchart of an example method for managing a preferred configuration and can be implemented in a suitable UE.

[0051] Figure 16 is a flowchart of an example method for managing a preferred configuration and can be implemented in a suitable UE. DETAILED DESCRIPTION

[0052] Figure 1A Describes an example wireless communication system 100, including a UE 102, base stations (BS) 104A, 106A, and a core network (CN) 110. Base stations 104A and 106A can operate in a RAN 105 connected to the same core network (CN) 110. For example, CN 110 can be implemented as an evolved packet core (EPC) 111 or a fifth - generation (5G) core (5GC) 160.

[0053] 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 generally configured to transport user plane data packets related to audio calls, video calls, Internet traffic, etc., and the MME 114 is configured to manage authentication, registration, paging, and other related functions. The 5GC 160 includes a User Plane Function (UPF) 162, an Access and Mobility Management Function (AMF) 164, and / or a Session Management Function (SMF) 166. Generally, the UPF 162 is configured to transport user plane packets related to audio calls, video calls, Internet traffic, etc., the AMF 164 is configured to manage authentication, registration, paging, and other related functions, and the SMF 166 is configured to manage PDU sessions.

[0054] As Figure 1A shown, base station 104A supports cell 124A, and base station 106A supports cell 126A. Cells 124A and 126A may partially overlap such that the UE 102 may perform DC communication with base stations 104A and 106A operating as a Master Node (MN) and a Secondary Node (SN), respectively. To directly exchange messages in the DC scenario and other scenarios discussed below, the MN 104A and the SN 106A may support an X2 or Xn interface. Generally, the CN 110 may be connected to any suitable number of base stations that support NR cells and / or EUTRA cells. An example configuration of the EPC 110 connected to additional base stations is discussed below with reference to Figure 1B discussed.

[0055] Base station 104A is equipped with processing hardware 130, which may include one or more general-purpose processors, such as a CPU, and a non-transitory computer-readable memory storing machine-readable instructions executable on one or more general-purpose processors and / or dedicated processing units. For example, when base station 104A operates as an MN, the processing hardware 130 in an example implementation includes an RRC controller 132 configured to manage RRC configurations, such as UE preferred configurations.

[0056] Base station 106A is equipped with processing hardware 140, which may also include one or more general-purpose processors, such as a CPU, and a non-transitory computer-readable memory storing machine-readable instructions executable on one or more general-purpose processors and / or dedicated processing units. For example, when base station 106A operates as an SN, the processing hardware 140 in an example implementation includes an RRC controller 142 configured to manage RRC configurations, such as UE preferred configurations.

[0057] Still referring to Figure 1A, the UE 102 is equipped with processing hardware 150, which may include one or more general-purpose processors, such as a CPU, and a non-transitory computer-readable memory that stores machine-readable instructions executable on one or more general-purpose processors and / or dedicated processing units. In an example implementation, the processing hardware 150 includes a UE RRC controller 152, which is configured to manage RRC configurations, such as UE preferred configurations.

[0058] More specifically, the RRC controllers 132, 142, and 152 can at least implement some of the techniques discussed with reference to the messaging and flowcharts below for managing RRC configurations. Although Figure 1A the RRC controllers 132 and 142 are illustrated as separate components, at least in some scenarios, the base stations 104A and 106A can have similar implementations and operate as MN or SN nodes in different scenarios. In these implementations, the base stations 104A and 106A can implement the RRC controller 132 and the RRC controller 142 respectively to support MN and SN functions.

[0059] In operation, the UE 102 can use radio bearers (e.g., DRB or SRB) that terminate at the MN 104A or the SN 106A at different times. The UE 102 can receive radio bearer configurations for configuring radio bearers from the MN 104A or the SN 106A. When the UE 102 communicates on a radio bearer in the uplink (from the UE 102 to the base station) and / or downlink (from the base station to the UE 102) direction, one or more security keys can be applied. In some cases, the UE can communicate with the base stations 104A and 106A using different RATs. Although the following examples specifically relate to a particular RAT type, 5G NR or EUTRA, generally, the techniques of the present invention are also applicable to other suitable radio access and / or core network technologies.

[0060] Figure 1B Another implementation of the example wireless communication system 100 is described, in which communication devices can implement the techniques discussed with reference to the messaging and flowcharts below to manage RRC configurations. As shown, in addition to the base stations 104A and 106A, the CN 110 is also connected to the base stations 104B and 106B. Although not shown to avoid clutter, each of the base stations 104B and 106B is equipped with processing hardware, including an RRC controller similar to the RRC controller 132A or 142A.

[0061] In certain implementations and scenarios, base station 104A may perform an immediate SN addition to configure UE 102 to operate in a dual connection (DC) with base station 104A (via the PCell) and base station 106A (via the PSCell instead of cell 126A). Base stations 104A and 106A serve as the MN and SN for UE 102, respectively. In some cases, UE 102 may operate in the MR-DC connection mode. For example, UE 102 may communicate with base station 104A using 5G NR, communicate with base station 106A using EUTRA, or communicate with base station 104A using EUTRA and communicate with base station 106A using 5G NR.

[0062] At some point, when UE 102 is in DC communication with MN 104A and S-SN 106A, MN 104A may perform an immediate SN change to change the SN of UE 102 from base station 106A (source SN or "S-SN") to base station 104B (target SN or "T-SN"). In another case, SN 106A may perform an immediate PSCell change to change the PSCell of UE 102 to cell 126A. In one implementation, SN 106A may send the configuration to change the PSCell to cell 126A to UE 102 via a signaling radio bearer (SRB) (e.g., SRB3) to immediately change the PSCell. In another implementation, SN 106A may send the configuration to UE 102 via MN 104A to immediately change the PSCell to cell 126A. MN 104A may send the configuration to immediately change the PSCell to cell 126A to UE 102 via SRB1.

[0063] In other cases, base station 104A may perform a conditional SN addition procedure to first configure base station 106B as the C-SN for UE 102, i.e., conditional SN addition or change (CSAC). At this time, UE 102 may be in SC with base station 104A, or in DC with base station 104A and base station 106A. If UE 102 is in DC with base station 104A and base station 106A, MN 104A may determine to perform the conditional SN addition procedure in response to a request received from base station 106A, or in response to one or more measurement results received from UE 102, or in response to one or more measurement results obtained by MN 104A from the measurement of the signal received from UE 101. Contrary to the immediate SN addition case discussed above, UE 102 does not immediately attempt to connect to C-SN106B. In this case, base station 104A operates as the MN again, but base station 106B initially operates as the C-SN instead of the SN.

[0064] More specifically, when the UE 102 receives the configuration of the C-SN 106B, the UE 102 does not connect to the C-SN 106B until the UE 102 determines that a certain condition is met (in some cases, the UE 102 may consider multiple conditions, but for the sake of convenience, the following discussion only involves a single condition). When the UE 102 determines that the condition has been met, the UE 102 connects to the C-SN 106B, and thus the C-SN 06B starts operating as the SN 106B of the UE 102. Therefore, although the base station 106B operates as a C-SN rather than an SN, the base station 106B has not been connected to the UE 102 and thus has not served the UE 102. In some implementations, the UE 102 can disconnect the connection from the SN 106A to the C-SN 106B.

[0065] In other cases, the UE 102 is in DC with the MN 104A (via the PCell) and the SN 106A (via the PSCell rather than 126A, not shown in Figure 1A ). The SN 106A can perform a Conditional PSCell Addition or Change (CPAC) to configure the candidate PSCell (C-PSCell) 126A of the UE102. If the UE 102 is configured with a Signaling Radio Bearer (SRB) (such as SRB3) to exchange RRC messages with the SN 106A, then in response to one or more measurement results that can be received from the UE 102 via the SRB or the MN 104A or that can be obtained by the SN106A from the measurement of the signal received from the UE 102, the SN 106A can send the configuration of the C-PSCell 126A to the UE 102 via the SRB. In the case of passing through the MN 104A, the MN 104B receives the configuration of the C-PSCell 126A. Contrary to the immediate PSCell change case discussed above, the UE 102 does not immediately disconnect from the PSCell and attempt to connect to the C-PSCell 126A.

[0066] More specifically, when the UE 102 receives the configuration of the C-PSCell 126A, the UE 102 does not connect to the C-PSCell 126A until the UE 102 determines that a certain condition is met (in some cases, the UE 102 may consider multiple conditions, but for the sake of convenience, the following discussion only refers to a single condition). When the UE 102 determines that the condition has been met, the UE 102 connects to the C-PSCell 126A, and thus the C-PSCell 126A starts to operate as the PSCell 126A of the UE 102. Therefore, although the cell 126A operates as a C-PSCell rather than a PSCell, the SN 106A may not yet be connected to the UE 102 via the cell 126A. In some implementations, the UE 102 may disconnect the connection from the PSCell to the C-PSCell 126A.

[0067] In some implementations and scenarios, the conditions associated with CSAC or CPAC can be that the signal strength / quality detected by UE 102 on the C-PSCell 126A of SN 106A or the C-PSCell 126B of C-SN 106B exceeds a certain threshold or corresponds to an acceptable measurement. For example, when one or more measurement results obtained by UE 102 on C-PSCell 126A are higher than the threshold configured by MN104A or SN 106A or higher than a predetermined or preconfigured threshold, UE 102 determines that the condition is met. When UE 102 determines that the signal strength / quality on the C-PSCell 126A of SN 106A is good enough (again, measured relative to one or more quantitative thresholds or other quantitative metrics), UE 102 can perform a random access procedure on C-PSCell 126A with SN 106A to connect to SN 106A. After UE 102 successfully completes the random access procedure on C-PSCell 126A, C-PSCell 126A becomes the PSCell26A of UE 102. Then, SN 106A can start communicating data (user plane data and / or control plane data) with UE 102 through PSCell 128A. In another example, when one or more measurement results obtained by UE 102 on C-PSCell 126B are higher than the threshold configured by MN 104A or C-SN 106B or higher than a predetermined or preconfigured threshold, UE 102 determines that the condition is met. When UE 102 determines that the signal strength / quality on the C-PSCell 126B of C-SN 106B is good enough (again, measured relative to one or more quantitative thresholds or other quantitative metrics), UE 102 can perform a random access procedure on C-PSCell 126B with C-SN 106B to connect to C-SN 106B. After UE 102 successfully completes the random access procedure on C-PSCell 126B, C-PSCell 126B becomes the PSCell 126B of UE 102, and C-SN 106B becomes SN 106B. Then, SN 106B can start communicating data (user plane data and / or control plane data) with UE 102 through PSCell126B.

[0068] In various configurations of the wireless communication system 100, base station 104A can be implemented as a master eNB (MeNB) or a master gNB (MgNB), and base stations 106A or 106B can be implemented as secondary gNBs (SgNBs) or candidate (C-SgNBs). UE 102 can communicate with base station 104A and base stations 106A or 106B (106A / B) via the same RAT (such as EUTRA or NR) or different RATs. When base station 104A is a MeNB and base station 106A is an SgNB, UE 102 can be in EUTRA-NR DC (EN-DC) with the MeNB and the SgNB. In this case, MeNB 104A may or may not configure base station 106B as a C-SgNB for UE 102. In this scenario, SgNBA 106A may configure cell 126A as a C-PSCell for UE 102. When base station 104A is a MeNB and base station 106A is a C-Sg NB in UE 102, UE 102 can be in SC with the MeNB. In this case, MeNB 104A may or may not configure base station 106B as another C-SgNB for UE 102.

[0069] In some cases, the MeNB, SeNB, or C-SgNB is implemented as an ng eNB instead of an eNB. When base station 104A is a master ng-eNB (Mng-eNB) and base station 106A is an SgNB, UE 102 can be in next-generation (NG) EUTRA-NR DC (NGEN-DC) with the Mng eNBA and the SgNB. In this case, Mng-eNB 104A may or may not configure base station 106B as a C-SgNB for UE 102. In this scenario, SgNB-106A may configure cell 126A as a C-PSCell for UE 102. When base station 104A is an Mng NB and base station 106A is a C-Sg NB in UE 102, UE 102 can be in SC with the Mng-NB. In this case, Mng-eNB 104A may or may not configure base station 106B as another C-SgNB for UE 102.

[0070] When base station 104A is a MgNB and base stations 106A / B are SgNBs, the UE 102 can be in NR-NR DC (NR-DC) with the MgNB and the SgNBs. In this case, the MeNB 104A may or may not configure base station 106B as the C-SgNB for the UE 102. In this scenario, the SgNBA 106A may configure cell 126A as the C-PSCell for the UE 102. When base station 104A is a MgNB and base station 106A is the C-Sg NB in the UE 102, the UE 102 may be in SC with the MgNB. In this case, the MgNB 104A may or may not configure base station 106B as another C-SgNB for the UE 102.

[0071] When base station 104A is a MgNB and base stations 106A / B are secondary ng-eNBs (Sng-eNBs), the UE 102 can be in NR-EUTRA DC (NE-DC) with the MgNB and the Sng-eNBs. In this case, the MgNB 104A may or may not configure base station 106B as the C-Sng-eNB for the UE 102. In this scenario, the Sng-eNB 106A may configure cell 126A as the C-PSCell for the UE 102. When base station 104A is a MgNB and base station 106A is the candidate Sng-eNB (C-Sng-eNB) for the UE 102, the UE 102 may be in SC with the MgNB. In this case, the MgNB 104A may or may not configure base station 106B as another C-Sng-eNB for the UE 102.

[0072] Base stations 104A, 104B, 106A, and 106B can be connected to the same core network (CN) 110, which can be an evolved packet core (EPC) 111 or a fifth-generation core (5GC) 160. Base station 104A can be implemented as an eNB supporting the S1 interface for communication with the EPC 111, an ng-eNB supporting the NG interface for communication with the 5GC 160, or a base station supporting the NR radio interface and the NG interface for communication with the 5GC 160. Base station 106A can be implemented as an EN-DC gNB (en-gNB) having an S1 interface with the EPC 111, an en-gNB not connected to the EPC 111, a gNB supporting the NR radio interface and the NG interface for the 5GC160, or an ng-eNB supporting the EUTRA radio interface and the NG interface for the 5GC 160. For direct message exchange in the scenarios discussed below, base stations 104A, 104B, 106A, and 106B can support the X2 or Xn interface.

[0073] AsFigure 1B As shown, base station 104A supports cell 124A, base station 104B supports cell 124B, base station 106A supports cell 126A, and base station 106B supports cell 126B. Cell 124A and 126A can partially overlap, and cell 124A and 124B can also partially overlap. In this way, UE 102 can perform DC communication with base station 104A (operating as an MN) and base station 106A (operating as an SN), and after completing the SN change, can perform DC communication with base station 104A (operating as an MN) and SN 104B. More specifically, when UE 102 operates in DC with base station 104A and base station 106A, base station 104A operates as a MeNB, Mng-eNB, or MgNB, and base station 106A operates as an SgNB or Sng-eNB. Cell 124A and 126B can partially overlap. When UE 102 is in SC with base station 104A, base station 104A operates as a MeNB, Mng-eNB, or MgNB, and base station 106B operates as a C-SgNB or C-Sng-eNB. When UE 102 operates in DC with base station 104A and base station 106A, base station 104A operates as a MeNB, Mng-eNB, or MgNB, base station 106A operates as an SgNB or Sng-eNB, and base station 106B operates as a C-SgNB or C-Sng-eNB.

[0074] Generally, the wireless communication network 100 can include any suitable number of base stations supporting NR cells and / or EUTRA cells. More specifically, EPC 111 or 5GC 160 can be connected to any suitable number of base stations supporting NR cells and / or EUTRA cells. Although the following examples specifically relate to specific CN types (EPC, 5GC) and RAT types (5G NR and EUTRA), generally, the techniques of the present invention are also applicable to other suitable radio access and / or core network technologies, such as sixth-generation (6G) radio access and / or 6G core network or 5G NR-6G DC.

[0075] In other configurations or scenarios of the wireless communication system 100, base stations 104A, 104B can operate as MeNB, Mng-eNB, or MgNB, and base stations 106A, 106B can operate as SgNB or Sng-eNB. UE 102 can communicate with base station 104A or 104B and base station 106A or 106B through the same radio access technology (RAT), such as EUTRA or NR, or through different RATs.

[0076] When base station 104A is a MeNB and base station 106A is an SgNB, UE 102 can be in EN-DC with MeNB 104A and SgNB 106A. When base station 104A is a Mng-eNB and base station 106A is an SgNB, UE 102 can be in NGEN-DC with Mng-eNB 104A and SgNB 106A. When base station 104A is a MgNB and base station 106A is an SgNB, UE 102 can be in NR-DC with MgNB 104A and SgNB 106A. When base station 104A is a MgNB and base station 106A is an Sng-eNB, UE 102 can be in NE-DC with MgNB 104A and Sng-eNB 106A.

[0077] Figure 1C Examples of distributed implementations of base stations (such as base stations 104A, 104B, 106A, or 106B) are described. The base stations in this implementation can include a central unit (CU) 172 and one or more distributed units (DUs) 174. The CU 172 is equipped with processing hardware, which can include one or more general-purpose processors, such as a CPU, and a non-transitory computer-readable memory that stores machine-readable instructions executable on one or more general-purpose processors, and / or a dedicated processing unit. In one example, the CU 172 is equipped with processing hardware 130. In another example, the CU 172 is equipped with processing hardware 140. The processing hardware 140 in the example implementation includes a (C-)SN RRC controller 142, configured to manage or control one or more RRC configurations and / or RRC procedures when base station 106A operates as an SN or a candidate SN (C-SN). Base station 106B can have the same or similar hardware as base station 106A. The DU 174 is also equipped with processing hardware, including one or more general-purpose processors, such as a CPU, and a non-transitory computer-readable memory that stores machine-readable instructions executable on one or more general-purpose processors, and / or a dedicated processing unit. In some examples, the processing hardware in the example implementation includes a media access control (MAC) controller configured to manage or control one or more MAC operations or procedures (e.g., random access procedures) and an RLC controller configured to manage or control one or more radio link control (RLC) operations or procedures when base station 106A operates as an MN, SN, or candidate SN (C-SN). The processing hardware can also include a physical layer controller configured to manage or control one or more physical layer operations or procedures.

[0078] Figure 2An example radio protocol stack 200 is shown in a simplified manner, and the UE 102 can communicate with an eNB / ng-eNB or gNB (e.g., one or more base stations 104A, 104B, 106A, 106B) according to the radio protocol stack 200. In the example stack 200, the physical layer (PHY) 202A of EUTRA provides a transport channel to the EUTRA MAC sublayer 204A, which in turn provides a logical channel to the EUTRA RLC sublayer 206A. The EUTRA RLC sublayer 206A in turn provides an RLC channel to the EUTRA PDCP sublayer 208 and, in some cases, also provides an RLC channel to the NR PDCP sublayer 210. Similarly, the NR PHY 202B provides a transport channel to the NR MAC sublayer 204B, which in turn provides a logical channel to the NR RLC sublayer 206B. The NR RLC sublayer 206B in turn provides an RLC channel to the NR PDCP sublayer 210. In some implementations, the UE 102 supports the EUTRA and NR stacks, as Figure 2 shown, to support handover between EUTRA and NR base stations and / or to support DC on the EUTRA and NR interfaces. Additionally, as Figure 2 shown, the UE 102 can support the NR PDCP sublayer 210 to be layered on the EUTRA RLC sublayer 206A.

[0079] The EUTRA PDCP sublayer 208 and the NR PDCP sublayer 210 receive data packets that can be referred to as service data units (SDUs) (e.g., from the Internet Protocol (IP) layer, directly or indirectly layered above the PDCP layer 208 or 210), and output data packets that can be referred to as protocol data units (PDUs) (e.g., to the RLC layer 206A or 206B). Unless the difference between the SDU and the PDU is relevant, for simplicity, this disclosure refers to both the SDU and the PDF as "data packets".

[0080] For example, on the control plane, the EUTRA PDCP sublayer 208 and the NR PDCP sublayer 210 can provide SRBs to exchange RRC messages. On the user plane, the EUTRA PDCP sublayer 208 and the NR PDCP sublayer 210 can provide DRBs to support data exchange.

[0081] In the case where UE 102 operates in EUTRA / NR DC (EN-DC), and base station 104A operates as a MeNB and base station 106A operates as an SgNB, radio communication system 100 may provide UE 102 with an MN-terminated bearer using the EUTRA PDCP sublayer 208, or an MN-terminated bearer using the NR PDCP sublayer 210. In various cases, radio communication system 100 may also provide UE 102 with an SN-terminated bearer using only the NR PCCP sublayer 210. The MN-terminated bearer may be an MCG bearer, an SCG bearer, or a split bearer. The SN-terminated bearer may be an MCG bearer, an SCG bearer, or a split bearer. The MN-terminated bearer may be an SRB (e.g., SRB1 or SRB2) or a DRB. The SN-terminated bearer may be an SRB or a DRB.

[0082] Next, refer to Figures 3A - 14BDiscuss several example scenarios where UE 102 and / or RAN 105 manage the UE preferred configuration (or interchangeably referred to herein as "preferred configuration" for simplicity). Generally, in these cases, UE 102 may send one or more preferred configurations (i.e., the first preferred configuration, the second preferred configuration, as described below) to the base stations of RAN 105 (e.g., base station 104A, base station 104B, base station 106A) in the UEAssistanceInformation message to suggest a temporary adjustment of the number of SCell, the number of MIMO layers, the aggregated bandwidth of UL and / or DL, and / or other suitable configuration parameters used when communicating with UE 102. Thus, in some implementations, the preferred configuration indicates the maximum number of SCell preferred by UE 102, the maximum number of MIMO layers, and / or the maximum aggregated bandwidth of uplink and downlink communications. As used herein, the "number of SCell" may include the PSCell, or optionally exclude the PSCell. In some implementations, the preferred configuration includes a discontinuous reception (DRX) configuration. The DRX configuration may include a DRX cycle and an on-duration (or off-duration). In other implementations, the preferred configuration includes an indication of enabling / disabling 5G, enabling / disabling DC, or enabling / disabling energy saving. In other implementations, the preferred configuration includes authorization assistance information configured for V2X sidelink communication (e.g., sl-UE-AssistanceInformationNR), the minimum scheduling offset for cross-slot scheduling (e.g., minSchedulingOffsetPreference), and / or an indication of interest in reference time information (e.g., referenceTimeInfoInterest). In some implementations, the UE assistance information message may be an existing RRC message, such as the UEAssistanceInformation message or a newly defined RRC message. In other implementations, the UE assistance information message may be an RRC response message in response to an RRC message that enables UE 102 to send the preferred configuration. In other implementations, UE 102 may indicate the release of the first preferred configuration in the second preferred configuration or the UE assistance information message. In other implementations, UE 102 may indicate the release of some parameters included in the first preferred configuration in the second preferred configuration or the UE assistance information message.

[0083] Now refer to Figures 3A - 3C , in various cases, UE 102 may release the preferred configuration before suspending the radio connection with the base station, or retain the preferred configuration after suspending the radio connection with the base station (and then overwrite the preferred configuration with a new preferred configuration when resuming the radio connection). UE 102 may be in an SC with the base station or in a DC with the base station and another base station. The base station may be an aggregated base station or a distributed base station including a central unit (CU) and a distributed unit (DU).

[0084] First, referring to Figure 3A , in scenario 300A, base station 104A serves as the serving base station for UE 102. In some implementations, base station 104A is a distributed base station, including a central unit (CU) 172 and a distributed unit (DU) 174, as Figure 3A shown. In other implementations, base station 104A is an aggregated base station (i.e., not split into a CU and a DU).

[0085] Initially, UE 102 operates in a connected state (e.g., RRC_CONNECTED) and communicates 302A data (e.g., uplink (UL) PDU and / or downlink (DL) PDU) with CU 172 and DU 174 in SC using a BS configuration that includes multiple configurations, each corresponding to respective configuration parameters. The configuration parameters specify SCell, MIMO layer, aggregated bandwidth, discontinuous reception (DRX) configuration, etc., configured to UE102 in the BS configuration. In other implementations and scenarios, although Figure 3A not shown, UE 102 may communicate 302A data with base station 104A operating as an MN and SN (e.g., base station 106A) in DC, or communicate 302A data with CU 172, DU 174, and a secondary DU in DC. In some implementations, during event 302A, CU 172 may receive the UE capabilities of UE 102 from UE 102, CN 110 (e.g., MME 114 or AMF 164), or another base station (e.g., base station 104B), and forward the UE capabilities to DU 174. In turn, DU 175 may establish multiple configuration parameters based on the UE capabilities. In some implementations, CU 172 may receive the UE capabilities in an information element (IE) (e.g., UE-EUTRA-Capability IE, UE-NR-Capability IE, and UE UE-MRDC-Capability IE) or a UE capability information message including the IE, and forward the IE or the UE capability information message to DU 174.

[0086] Subsequently, CU 172 performs a 304A UE-assisted configuration procedure with UE 102 via DU 174, enabling UE 102 to (i.e., be licensed or permitted to) send a preferred configuration to base station 104A. In some implementations, during the UE-assisted configuration procedure, CU 172 may send an RRC message (e.g., an RRC reconfiguration message or a newly defined RRC message) to UE 102 via DU 174, enabling UE 102 to send the preferred configuration. Subsequently, UE 102 may send an RRC response message (e.g., an RRC reconfiguration complete message or a newly defined RRC response message) to CU 172 via DU 174. CU 172 may include a field or IE (e.g., a newly defined field / IE or an existing field / IE in 3GPP specification 36.331 or 38.331) in the RRC message to enable UE 102 to send the preferred configuration. For example, CU 172 may include an OtherConfig IE, an overheating configuration (e.g., an OverheatingAssistanceIE or an overheatingAssistanceConfig field), an energy-saving configuration (e.g., a PowerPrefIndicationConfigIE), or an OtherConfig IE that includes an OverheatingAssistanceConfig IE, an overheatingAssistanceConfig field, and / or a PowerPrefIndicationConfig IE in the RRC message to enable UE 102 to provide the preferred configuration.In another example, the CU 172 may include in the RRC message a reference time of interest report (e.g., referenceTimeInterestReporting-r16), a sidelink configuration (e.g., sl-AssistanceConfigNR-r16), an in-device coexistence (IDC) configuration (e.g., idc-AssistanceConfig), a Bluetooth configuration (e.g., btNameList-r16), and a wireless local area network (WLAN) configuration (e.g., wlanNameList-r16), a sensor configuration (e.g., sensorNameList-r16), a location configuration (e.g., obtainCommonLocationConfig-r16), and / or at least one power saving configuration (e.g., drx-PreferenceConfig-r16, maxBW-PreferenceConfig-r16, maxCC-PreferenceConfig-r16, maxMIMO-LayerPreferenceConfig-r16, minSchedulingOffsetPreferenceConfig-r16, releasePreferenceConfig-r16) to enable the UE 102 to provide a preferred configuration. In other implementations, during the UE assistance configuration process, the CU 172 may broadcast an RRC message (e.g., a system information block) via the PCell 124A to enable the UE 102 to send a preferred configuration.

[0087] After the UE 102 is enabled to send a preferred configuration, the UE 102 sends 306A a UE assistance information message including the preferred configuration (i.e., the first preferred configuration) to the DU 174. The DU 174 then sends 308A the UE assistance information message to the CU 172. Events 306A and 308A are collectively referred to as the UE assistance information process 372A in Figure 3A which.

[0088] In various scenarios and implementations, the UE 102 may send the first preferred configuration 306A for different reasons. In one implementation, as described in event 302A (i.e., the configuration parameters do not meet the preferences of the UE 102 defined in the first preferred configuration), if the UE 102 does not meet the configuration parameters in the BS configuration used for communication between the UE 1021 and the base station 104A, the UE 102 may send the first preferred configuration. In another implementation, even if the UE 102 is satisfied with the configuration parameters, the UE 102 may send the first preferred configuration to prevent the base station 104A from changing the configuration parameters to a configuration parameter that the UE 102 may not like. In another implementation, if the UE 102 experiences an overheating situation (e.g., due to heavy application process handling), detects a low battery level, or otherwise determines to save energy (e.g., in response to an overheating configuration in an RRC message received from the base station 104A), the UE 102 may send the first preferred configuration. In this way, the UE 102 may send the first preferred configuration for energy-saving purposes (even if the UE 102 does not have an overheating situation), or for overheating purposes, or both.

[0089] In response to receiving the 308A UE assistance information message from the DU 174, the CU 172 sends the 310A first interface message including the first preferred configuration (e.g., UE Context Modification Request message, UE Context Setup Reqeust message) to the DU 174. In some implementations, if the configuration parameters in the BS configuration do not meet the first preferred configuration, or if the DU 174 determines to modify the configuration parameters, although the configuration parameters meet the first preferred configuration, the DU 174 generates the 312A DU configuration for the UE 102 in response to the first preferred configuration. The DU 174 generates the DU configuration in a manner that does not exceed the capabilities of the UE 102, e.g., by considering the UE capabilities included in the first interface message received from the CU 172 in event 310A.

[0090] In some scenarios and implementations, the UE 102 may send a first preferred configuration to the base station 104A to request the base station 104A to generate a DU configuration that does not maximize the capabilities defined in the UE capabilities of the UE 102. For example, in response to receiving the first preferred configuration from the UE 102, indicating a preferred maximum number of SCell, a preferred maximum number of MIMO layers, and / or a maximum aggregated bandwidth of SCell that is less than the maximum number of corresponding SCell supported by the UE capabilities, the base station 104A may generate a DU configuration indicating a preferred maximum number of SCell, MIMO layers, and / or aggregated bandwidth not exceeding that indicated in the first preferred configuration. In fact, the DU configuration for the UE 102 may be generated by the base station 104A (e.g., the DU 174 of the base station 104A) to release a part of the SCell, MIMO layers, and / or aggregated bandwidth indicated for event 302A in the above BS configuration, to ensure that the UE102 communicates with the DU 174 through the preferred maximum number of SCell, MIMO layers, and / or aggregated bandwidth or less than that indicated in the first preferred configuration.

[0091] After the DU 174 generates the DU configuration in event 312A, the DU 174 may send a second interface message (e.g., UE Context Modification Response message, UE Context ModificationRequired message, UE Context Setup Response message) including the DU configuration to the CU 172. In other implementations, in response to receiving the 310A first preferred configuration, if the configuration parameters in the BS configuration meet the first preferred configuration, the DU 174 does not need to generate a DU configuration. In this case, the DU 174 may omit the DU configuration in the second interface message, or include a DU configuration unrelated to the first preferred configuration in the second interface message. In response to the second interface message received from the DU 174, the CU 172 may send a UE context modification confirmation message to the DU 174. Events 310A, 312A, and 314A are collectively referred to as the DU reconfiguration process 374A in Figure 3A which is collectively referred to as the DU reconfiguration process 374A.

[0092] In some implementations, after receiving the DU configuration from the DU 174, the CU 172 sends a 316A RRC reconfiguration message including the DU configuration to the DU 174, which in turn sends a 318A RRC reconfiguration message to the UE 102. In response, the UE 102 may send a 320A RRC reconfiguration complete message to the DU 174, which in turn sends a 322A RRC reconfiguration complete message to the CU 172. By receiving the DU configuration, the UE 102 can update a plurality of configuration parameters provided by the base station 104A before event 302A with the DU configuration and communicate with the DU 174 using the updated configuration parameters. In some implementations, the CU 172 may send a 316A DL RRC Message Transfer message including the RRC reconfiguration message to the DU 174, which in turn sends a 322A UL RRC Message Transfer message including the RRC reconfiguration complete message. Events 316A, 318A, 320A, and 322A are collectively referred to in Figure 3A as the RRC reconfiguration procedure 376A.

[0093] Although the DU 174 is described as generating one DU configuration in step 312A, the DU 174 may generate multiple DU configurations. If the DU 174 generates multiple DU configurations, the CU 172 and the UE 102 may execute the RRC reconfiguration procedure 376A multiple times, enabling the UE 102 to obtain multiple DU configurations.

[0094] In some scenarios and implementations, after receiving a first preferred configuration at event 372A, the CU 172 may perform a DU reconfiguration procedure with a candidate DU (C-DU), e.g., the DU 174 or Figure 3A a DU not shown in, similar to the DU reconfiguration procedure 374A, to prepare a conditional configuration for a conditional handover (CHO) of the UE 102. During the DU reconfiguration procedure, the CU 172 may send a first interface message similar to event 310A to the C-DU to obtain a C-DU configuration generated by the C-DU that meets the first preferred configuration. In other scenarios and implementations, before or after event 372A, the CU 172 may perform a DU reconfiguration procedure with the C-DU, e.g., the DU 174 or Figure 3AThe DU not shown in the figure, similar to the DU reconfiguration procedure 374A, prepares a conditional configuration for the CHO of the UE 102. During the DU reconfiguration procedure, the CU 174 may send a first interface message, similar to event 310A but excluding the first preferred configuration, to obtain a C-DU configuration generated by the C-DU based on the UE capabilities stored in the C-DU or included in the first interface message.

[0095] In any case, after the CU 172 obtains the C-DU configuration, the CU 174 generates an RRC message including the C-DU configuration, including the conditional configuration of the RRC message and the RRC reconfiguration message including the conditional configuration. Then, the CU 172 sends the RRC reconfiguration message to the UE 102 via the DU174. The UE 102 may send an RRC reconfiguration complete message to the CU 172 via the DU 174 as a response. Subsequently, if the UE 102 detects that the conditions for connecting to the candidate cell are met, the UE 102 connects to the C-DU via the candidate cell. The CU 172 may perform a DU reconfiguration procedure and an RRC reconfiguration procedure with the UE 102 and the C-DU to send another DU configuration that meets the first preferred configuration to the UE 102, similar to the DU reconfiguration procedure 374A and the RRC reconfiguration procedure 376A.

[0096] If the CU 172 sends a conditional configuration (i.e., the first conditional configuration) to the UE 102 before receiving the first preferred configuration from the UE 102, then in one implementation, even if the conditional configuration does not meet the first preferred configuration, the CU 172 may not update the conditional configuration. In another implementation, if the conditional configuration does not meet the first preferred configuration, the CU 172 may send an RRC reconfiguration message to the UE 102 to release the conditional configuration. In another implementation, the CU 172 may send an RRC reconfiguration message to the UE 102 in response to the first preferred configuration received from the UE 102 to release the conditional configuration. In another implementation, if the conditional configuration does not meet the first preferred configuration received from the UE 101, the CU 172 may send an RRC reconfiguration message including another conditional configuration (i.e., the second conditional configuration) to the UE 102 to replace the first conditional configuration. The CU 172 may perform a DU reconfiguration procedure with the C-DU to obtain a new C-DU configuration that meets the first preferred configuration and send the second conditional configuration (including the new C-DU configuration) to the UE 102 in a similar manner as described above.

[0097] In certain scenarios and implementations, after receiving the first preferred configuration in event 372A, the CU 172 may communicate with a candidate base station (C-BS) (e.g., Figure 3AThe base station 106B (not shown in Figure 3A the figure) performs a handover preparation process to prepare the conditional configuration for the CHO of the UE 102. During the handover preparation reconfiguration process, the CU 172 may send a Handover Request message (i.e., a CHO command) to the C-BS to obtain the C-BS configuration. The C-BS may generate a C-BS configuration that meets the first preferred configuration and send a Handover Request Acknowledge message including the C-BS configuration to the CU 172 in response to the handover request message. In other scenarios and implementations, before or after event 372A, the CU 172 may communicate with the C-BS (e.g.,

[0098] the base station 106B not shown in the figure) to perform a handover preparation process to prepare the conditional configuration for the CHO of the UE 102. During the handover preparation reconfiguration process, the CU 172 may send a handover request message that does not include the first preferred configuration to the C-BS to obtain the C-BS configuration. The C-BS may generate a C-BS configuration based on the UE capabilities included in the handover request message and send a handover request acknowledgment message including the C-BS configuration to the CU 172 in response to the handover request message.

[0099] If the CU 172 sends a conditional configuration (i.e., the first conditional configuration) to the UE 102 before receiving the first preferred configuration from the UE 102, then in one implementation, even if the conditional configuration does not meet the first preferred configuration, the CU 172 may not update the conditional configuration. In another implementation, if the conditional configuration does not meet the first preferred configuration, the CU 172 may send an RRC reconfiguration message to the UE 102 to release the conditional configuration. In another implementation, the CU 172 may send an RRC reconfiguration message to the UE 102 to release the conditional configuration in response to the first preferred configuration received from the UE 102. In another implementation, if the conditional configuration does not meet the first preferred configuration received from the UE 101, the CU 172 may send an RRC reconfiguration message including another conditional configuration (i.e., the second conditional configuration) to the UE 102 to replace the first conditional configuration. The CU 172 may perform a DU reconfiguration process with the C-DU to obtain a new C-DU configuration that meets the first preferred configuration and send the second conditional configuration (including the new C-DU configuration) to the UE 102 in a similar manner as described above.

[0100] At a later time (e.g., after the CU 172 detects that the traffic of the UE 102 is inactive on the radio bearer(s) received at the BS side), the CU 172 determines to suspend the radio connection (e.g., including the RRC connection) with the UE 102. Then, the CU 174 sends a 324A RRC suspension (RRC suspend) message (e.g., RRCRelease message, RRCConnectionRelease message) to the DU 174, which in turn sends a 326A RRC suspension message to the UE 102. Accordingly, the UE 102 suspends the 328A radio connection and may transition to the inactive state or the idle state. In some implementations, the CU 172 may send a 324A UE Context Release Command (UE context release command) message including the RRC suspension message to the DU174, which may in turn send a UE Context Release Complete (UE context release complete) message to the CU 172 as a response. The RRC suspension message may include a SuspendConfigIE, an RRC-InactiveConfig-r15 IE, or a ResumeIdentity-r13 IE. Events 324A, 326A, and 328A are collectively referred to as the RRC suspension process 378A in Figure 3A which is collectively referred to as the RRC suspension process 378A.

[0101] As described above, in some implementations, in response to receiving the first preferred configuration 310A, if the configuration parameters in the BS configuration meet the first preferred configuration, the DU 174 does not need to generate a DU configuration. In these implementations, the base station 104A does not need to perform the DU reconfiguration process 374A and the RRC reconfiguration process 376A before the RRC suspension process 378A. The base station 104A may not perform the DU reconfiguration process 374A and the RRC reconfiguration process 376A for other reasons, such as when the CU 172 transmits a large amount of data to the UE 102, or when it is busy for other reasons.

[0102] Later, after suspending the radio connection 328A, the UE 102 can perform the RRC resume process 380A to transition from the inactive or idle state to the connected state. For example, in response to determining to initiate data transmission with the base station 104A, or in response to a Paging message received from the base station 104A. In the RRC resume process 380A, the UE 102 sends a 330A RRC resume request message to the DU 174, which in turn sends a 332A RRC resume request message to the CU 172. In response, the CU 174 sends a 334A RRC resume message to the DU 174, which in turn sends a 336A RRC resume message to the UE 102. Therefore, the UE 102 resumes the suspended radio connection 338A in response to the RRC resume message and transitions to the connected state. The UE 102 can send a 340A RRC resume complete message to the DU 174, and in turn can send a 342A RRC resume complete message to the CU 172. Although the UE 102 is described as using the DU 174 to perform the RRC resume process 380A, in other implementations, the UE 102 can perform the RRC resume process 380A with another DU (i.e., different from the DU 174) connected to the CU 172.

[0103] In some implementations, after the UE 102 and the base station 104A perform the RRC suspension procedure 378A, the UE 102 may release 352A the first preferred configuration (e.g., in response to receiving the 326A RRC suspension message). Similarly, in some implementations, the CU 172 may release 351A the first preferred configuration in response to determining to suspend the radio connection with the UE 102. In other implementations, during the RRC resume procedure 380A (e.g., in response to receiving the 336A RRC resume message), or after sending the 340A RRC resume complete message, the UE 102 may release 352A the first preferred configuration in response to initiating the RRC resume procedure 380A (e.g., sending the 330A RRC resume request message). Similarly, in some implementations, during the RRC resume procedure 380A (e.g., in response to receiving the 332A RRC resume request message and sending the 334A RRC resume message), or after receiving the 342A RRC resume complete message, the CU 172 may release 351A the first preferred configuration.

[0104] By releasing the first preferred configuration at the UE 102 and the CU 172, when resuming the suspended radio connection, the communication between the UE 102 and the CU 172 does not have to be limited to communicating with each other according to the first preferred configuration. For example, the UE 102 may have recovered from an overheating condition or an increase in battery power since the inactive state or the idle state, such that the UE 102 can utilize more SCell, MIMO layers, and / or aggregated bandwidth than indicated in the first preferred configuration after transitioning back to the connected state. For example, since the UE 102 and the CU 172 still know the BS configuration (including the updated configuration parameters configured through the RRC reconfiguration procedure 376A), the UE 102 and the CU 1722 can continue to communicate using the BS configuration.

[0105] In some implementations, in addition to releasing the first preferred configuration, the UE 102 may also release or retain some or all of the configurations in the BS configuration in response to receiving the 326A RRC suspension (RRC suspension) message (i.e., when the UE 102 is in the inactive state or the idle state). Similarly, in addition to releasing the first preferred configuration, when the UE 102 is in the inactive state or the idle state, the CU 172 may also release or retain some or all of the configurations in the BS configuration. In some implementations, if the UE 102 receives the configuration in the RRC resume message from the base station 104A at event 336A, the UE 102 may release or update the configurations retained in the BS configuration. In one such implementation, the CU 172 may obtain another DU configuration (i.e., the second DU setting) from the DU 174, for example, by using the UE context establishment procedure (as follows Figure 4Aas described), and include the second DU configuration in the RRC resume message. In another such implementation, the CU 172 may generate a configuration and include the generated configuration in the RRC resume message. In other implementations, after receiving the RRC resume complete message, the CU 172 may obtain another DU configuration (i.e., the second DU setting) from the DU 174, e.g., by using a DU reconfiguration procedure similar to the DU reconfiguration procedure 374A, and perform an RRC reconfiguration procedure with the UE 102, similar to the RRC reconfiguration procedure 376A. The CU 172 may include the second DU configuration in the RRC reconfiguration message of the RRC reconfiguration procedure. Since the CU 172 releases the first preferred configuration at event 351A, during the DU reconfiguration procedure or the UE context establishment procedure, the CU 172s do not send the first preferred configuration to the DU 174 (see Figure 4A ). Therefore, the DU 174 generates the second DU configuration in a manner that does not underestimate the capabilities of the UE 102, e.g., by considering the UE capabilities rather than the first preferred configuration.

[0106] In some implementations, when the UE 102 is in the inactive state or the idle state, the UE 102 may retain the current security keys (e.g., K gNB and K RRCint keys), may retain the robust header compression (ROHC) state if the UE 102 is configured with ROHC, the QoS flow to DRB mapping rules, the cell radio network temporary identifier (C-RNTI) used in the source PCell (e.g., PCell 124A), the cell identity and the physical cell identity of the source PCell, and other configuration parameters in the radio link control (RLC) configuration (e.g., RLCBearerConfig IE), the media access control (MAC) configuration (e.g., MAC-CellGroupConfig IE), and / or the physical layer configuration (e.g., PhysicalCellGroupConfig IE). In some implementations, when the UE 102 is in the inactive state or the idle state, the UE 102 may retain the fields or IEs that enable the UE 102 to send the first preferred configuration. In other implementations, in response to the RRC suspend message in the RRC suspend procedure 378A or during the RRC resume procedure 380A, the UE 102 may release the configuration and / or the fields or IEs that enable the UE 102 to send the first preferred configuration within the ReconfigurationWithSync IE and / or the ServingCellConfigCommonSIB IE.

[0107] In some implementations, after the RRC Suspend procedure 378A is performed between the base station 104A and the UE 102, the UE 102 may release the OtherConfig IE, overheat configuration, and / or power saving configuration (e.g., in response to receiving the 326A RRC Suspend message). Similarly, in some implementations, in response to determining to suspend the radio connection with the UE 102, the CU 172 may release the OtherConfig IE, overheat configuration, and / or power saving configuration. In other implementations, during the RRC Resume procedure 380A (e.g., in response to receiving the 336A RRC Resume message), or after sending the 340A RRC Reply Complete message, in response to initiating the RRC Resume procedure 380A (e.g., sending the 330A RRC Resume Request message), the UE 102 may release the OtherConfig IE, overheat configuration, and / or power saving configuration. Similarly, in some implementations, during the RRC Resume procedure 380A (e.g., in response to receiving the 332A RRC Resume Request message, sending the 334A RRC Resume message), or after receiving the 342A RRC Resume Complete message, the CU 172 may release the OtherConfig IE, overheat configuration, and / or power saving configuration. The UE 102 may disable the transmission of UE assistance information messages in response to releasing the OtherConfig IE, overheat configuration, and / or power saving configuration.

[0108] In the first preferred configuration or the UE assistance information message, the UE 102 may include the reducedCCsDL field to indicate the preferred maximum number of SCell. The UE 102 may or may not include the reducedCCsUL field in the first preferred configuration or the UE assistance information message. If the CU 172 or the DU 174 receives the reducedCCsDL field with a value of X and the reducedCCsUL field with a value of Y, and X is less than Y, then the CU 172 or the DU 175 may ignore the reducedCCsUL field.

[0109] In some implementations, the above DU configuration includes at least one of a physical configuration, a media access control (MAC) configuration, and a radio link configuration. The DU configuration may not include a radio bearer configuration. For example, the DU configuration may be a CellGroupConfig IE, a RadioResourceConfigDedicated IE, an RRCConnectionReconfiguration-r8-IEs IE, or an RRCReconfiguration-IEs IE.

[0110] In some implementations, the above BS configuration may be an RRCReconfiguration message, RRCReconfiguration-IEs, or CellGroupConfig IE that complies with 3GPP TS 38.331, or an RRCConnectionReconfiguration message or RRCConnectionReconfiguration-IEs that complies with 3GPP TS 36.331. In other implementations, the BS configuration may include configurations in CellGroupConfig IE, RRCReconfiguration-IEs, or RRCConnectionReconfiguration-IEs. In other implementations, the base station configuration may include configurations in ServingCellConfigCommonSIB IE. In other implementations, the BS configuration may further include radio bearer configurations (RadioBearerConfig IE, DRB-ToAddMod IE, and / or SRB-ToAddMod IE) and / or measurement configurations (MeasConfig IE).

[0111] In some implementations, if base station 104A is a gNB, the RRC reconfiguration message and the RRC reconfiguration complete message may be an RRCReconfiguration message and an RRCReconfigurationComplete message, respectively. In other implementations, if base station 104A is an eNB or ng-eNB, the RRC reconfiguration message and the RRC reconfiguration complete message may be an RRCConnectionReconfiguration message and an RRCConnectionReconfigurationComplete message, respectively.

[0112] In some implementations, if base station 104A is a gNB, the RRC resume request message, the RRC resume message, and the RRC resume complete message may be an RRCResumeRequest message, an RRCResume message, and an RRCResumeComplete message, respectively. In other implementations, if base station 104A is an eNB or ng-eNB, the RRC resume request message, the RRC resume message, and the RRC resume complete message may be an RRCConnectionResumeReuquest message, an RRCConnectionResume message, and an RRCConnectionResumeComplete message, respectively.

[0113] Now refer to Figure 3B, in scenario 300B, base station 104A operates as the serving base station of UE 102 again, similar to scenario 300A. However, in Figure 3A , when UE 102 and CU 172 resume communicating with each other, they release the first preferred configuration to resume using the BS configuration, while in Figure 3B , UE 102 and base station 104A retain the first preferred configuration. Subsequently, UE 102 provides a second preferred configuration to overwrite the retained first preferred configuration when resuming the connection with CU 172. Therefore, UE 101 initially retained the first preferred configuration, but still released the first preferred configuration before communicating data with RAN 105 via the radio connection.

[0114] Generally, Figure 3B the CU 172 and DU 174 in Figure 3A can perform similar actions to the CU 172 and DU 174 in

[0115] Initially, UE 102 operates in the connected state and communicates 302B data with CU 172 and DU 174 via cell 124A using a BS configuration that includes multiple configurations (each configuration corresponding to corresponding configuration parameters), similar to event 302A.

[0116] Later, CU 172 performs a 304B UE-assisted configuration procedure with UE 102 via DU 174 to enable UE 102 to send a preferred configuration to base station 104A, similar to event 304A.

[0117] After UE 102 is able to send the preferred configuration, UE 102 performs a UE-assisted information procedure 372B with DU 174 and CU 172, similar to the UE-assisted signal procedure 372A, thereby providing the preferred configuration (i.e., the first preferred configuration) to DU 174 and further providing the first preferred configuration to CU 172.

[0118] In response to receiving the first preferred configuration from DU 174, CU 172 performs a DU reconfiguration procedure 374B with DU 174, similar to the DU reconfiguration procedure 374A, thereby receiving from DU 175 a DU configuration (i.e., the first DU configuration) indicating a preferred maximum number of SCell, MIMO layers, and / or aggregated bandwidth not exceeding that indicated in the first preferred configuration.

[0119] In some implementations, after receiving the first DU configuration from DU 174, CU 172 performs an RRC reconfiguration procedure 376B with DU 174 and UE 102, similar to RRC reconfiguration procedure 376A. Thus, UE 102 can use the first DU configuration to update multiple configuration parameters previously provided by base station 104A in event 302B and communicate with DU 174 using the updated configuration parameters.

[0120] At a later time (e.g., after CU 172 detects that the traffic of UE 102 is inactive on the radio bearer at the BS side), CU 172 determines to suspend the radio connection (e.g., including the RRC connection) with UE 102. In response to determining to suspend the radio connection, CU 174 performs an RRC suspension procedure 378B, similar to RRC suspension procedure 378A. Thus, UE 102 suspends the radio connection and can transition to an inactive state or an idle state.

[0121] At a later time, after suspending the radio connection, UE 102 can perform an RRC resume procedure 380B to transition from an inactive or idle state to a connected state, similar to RRC resume procedure 380A. As a result, UE 102 resumes the suspended radio connection 338B and transitions to the connected state. UE 102 can send an RRC resume complete message 340B to DU 174, which in turn can send an RRC resume complete message 342B to CU 172, similar to events 340A and 342A respectively.

[0122] In some implementations, after the base station 104A and UE 102 perform the RRC suspension procedure 378B, UE 102 can retain 354B the first preferred configuration (e.g., in response to receiving an RRC suspension message during the RRC suspension procedure 378B). Similarly, in some implementations, CU 172 can retain 353B the first preferred configuration in response to determining to suspend the radio connection with UE 102. In other implementations, UE 102 can retain 354B the first preferred setting in response to initiating the RRC resume procedure 380B or during the RRC resume procedure 380B. Similarly, in some implementations, CU 172 can retain 353B the first preferred configuration during the RRC resume procedure 380B.

[0123] After UE 102 resumes the suspended radio connection 338B and transitions to the connected state, UE 102 sends another UE assistance information message 344B to DU 174, including another preferred configuration (i.e., the second preferred configuration). DU 174 in turn sends a UE assistance information message 346B to CU 172.

[0124] By sending a second preferred configuration to CU 172 via DU 174, UE 102 can overwrite the first preferred configuration reserved at CU 172 so that when reconnecting with CU 174, UE 101 and CU 172 can communicate using the second preferred configuration. Thus, contrary to the first preferred configuration released as described above with respect to Figure 3A UE 102 and CU 172 may alternatively retain the first preferred configuration but overwrite the first preferred configuration with the second preferred configuration for use after reconnecting.

[0125] In various scenarios and implementations, UE 102 may send the 344B second preferred configuration for different reasons. In one implementation, as described in event 302A, if UE 102 meets the configuration parameters in the BS configuration used for UE 102 to communicate with base station 104A, then UE 102 may send the second preferred configuration, as described in event 320A (i.e., the configuration parameters meet the preferences of UE 102 defined in the second preferred configuration). In another implementation, if UE 102 no longer experiences an overheating situation, no longer detects a low battery level, or no longer decides to conserve energy, then UE 102 may send the second preferred configuration. In another implementation, if UE 102 experiences a different overheating situation (e.g., a less severe or more severe situation) or decides to conserve less or more power, then UE 102 may send the second preferred configuration. In another implementation, if the degree of overheating that UE 102 experiences is greater than the overheating situation that triggers UE 102 to generate the first preferred configuration, then UE 102 may send the second preferred configuration.

[0126] In response to receiving the 346B UE assistance information message from DU 174, CU 172 sends a 362B fourth interface message (e.g., UE context modification request message) including the second preferred configuration to DU 174. In some implementations, if the configuration parameters of UE 102 updated during the RRC reconfiguration process 376B due to receiving the first DU configuration do not meet the second preferred configuration, or if although the configuration parameters meet the second preferred configuration but DU 174 determines to modify the configuration parameters, then DU 174 generates a 364B another DU configuration (i.e., the second DU configuration) for UE 102. For example, by considering UE capabilities, DU 174 generates the second DU configuration in a manner that does not exceed the capabilities of UE 102.

[0127] In certain scenarios and implementations, the UE 102 may send a second preferred configuration to the base station 104A to request the base station 104A to generate a second DU configuration that does not maximize the capabilities of the UE 102 as defined in the UE capabilities. For example, in response to receiving the second preferred configuration from the UE 102, indicating a preferred maximum number of SCell, MIMO layers, and / or aggregated bandwidth that is less than the corresponding maximum number supported by the UE capabilities, but greater than the corresponding maximum number of SCell, MIMO layers, and / or aggregated bandwidth indicated in the first preferred configuration, the base station 104A may generate a second DU configuration indicating a preferred maximum number of SCell, MIMO layers, and / or aggregated bandwidth not exceeding that indicated in the second preferred configuration. As another example, the second preferred configuration may indicate the same number of SCell, MIMO layers, and / or aggregated bandwidth supported by the UE capabilities or indicated in the BS configuration.

[0128] After the DU 174 generates the second DU configuration in event 364B, the DU 174 may send a fourth interface message (e.g., UE context modification response message, UE context modification request message) including the second DU configuration to the CU 172. In other implementations, in response to receiving the second preferred configuration 362B, if the configuration parameters in the first preferred configuration meet the second preferred configuration, the DU 174 does not need to generate the second DU configuration. In this case, the DU 174 may omit the second DU configuration in the fourth interface message or may include a second DU configuration unrelated to the first preferred configuration in the fourth interface message. In response to receiving the fourth interface message from the DU 174, the CU 172 may send a UE context modification confirmation message to the DU 174. Events 362B, 364B, and 366B are collectively referred to as the second DU reconfiguration process 382B in Figure 3B which is collectively referred to as the second DU reconfiguration process 382B.

[0129] In some implementations, after CU 172 receives a second DU configuration from DU 174, it sends a 317B RRC reconfiguration message including the second DU configuration to DU 174, which in turn sends a 319B RRC reconfiguration message to UE 102. In response, UE 102 may send a 321B RRC reconfiguration complete message to DU 174, which in turn sends a 323B RRC reconfiguration complete message to CU 172. Thus, UE 102 can update multiple configuration parameters previously updated according to the first preferred configuration with the second DU configuration and communicate with DU 174 by using the updated configuration parameters. In some implementations, CU 172 may send a 317B DL RRC message transmission message including an RRC reconfiguration message to DU 174, and may in turn send a 323B UL RRC information transmission message including an RRC reconfiguration complete message. Events 317B, 319B, 321B, and 323B are collectively referred to as the second RRC reconfiguration process 384B in Figure 3B which is collectively referred to as the second RRC reconfiguration process 384B.

[0130] Now referring to Figure 3C , in scenario 300C, base station 104A again operates as the serving base station of UE 102, similar to scenario 300A. While in Figure 3A , UE 102 and base station 104A perform an RRC suspension process before UE 102 and base station 104A release the first preferred configuration, and in Figure 3C , UE 102 and base station 104 release the first preferred configuration before performing the RRC suspension process. Generally, Figure 3C the CU 172 and DU 174 in Figure 3A can perform actions similar to those of PU 172 and DU 174 in

[0131] Initially, UE 102 operates in the connected state and communicates 302C data with CU 172 and DU 174 through cell 124A by using a BS configuration including multiple configurations, each corresponding to a respective configuration parameter, similar to event 302A.

[0132] Later, UE 102 and base station 104A respectively perform a UE assisted configuration process 304C, a UE assisted information process 372C, a DU reconfiguration process 374C, and an RRC reconfiguration process 376C, similar to events 304A, 372A, 374A, and 376A.

[0133] After performing the RRC reconfiguration procedure 376C, the UE 102 and the base station 104A perform the 382C UE-assisted release procedure. In some implementations, during the UE-assisted release procedure, the CU 172 may send an RRC message (e.g., an RRC reconfiguration message or a newly defined RRC message) to the UE 102 via the DU 174 to instruct the UE 102 to release the first preferred configuration. Subsequently, in some implementations, the UE 102 may release the 352C first preferred configuration, and the CU 172 may release the 351C first preferred configuration, similar to events 352A and 351A respectively. In some implementations, the UE 102 may release the OtherConfig IE, overheat configuration, and / or energy-saving configuration in response to the UE-assisted release procedure. The UE 102 may disable the transmission of the UE-assisted information message in response to the release of the OtherConfig IE, overheat configuration, and / or energy-saving configuration. Similarly, in some implementations, the CU 172 may release the OtherConfig IE, IE, overheat configuration, and / or energy-saving configuration in response to the UE-assisted release procedure.

[0134] At a later time (e.g., after the CU 172 detects that the traffic of the UE 102 is inactive on the bearer received at the BS), the CU 172 determines to suspend the radio connection with the UE 102 (e.g., including the RRC connection). In response to determining to suspend the radio connection, the CU 174 performs the RRC suspension procedure 378C, similar to the RRC suspension procedure 378A. Accordingly, the UE 102 suspends the radio connection and may transition to the inactive state or the idle state.

[0135] After suspending the radio connection, the UE 102 may perform the RRC resume procedure 380C to transition from the inactive or idle state to the connected state, similar to the RRC resume procedure 380A. As a result, the UE 102 resumes the 338C suspended radio connection and transitions to the connected state. The UE 102 may send a 340C RRC resume complete message to the DU 174, which may in turn send a 342C RRC resume complete message to the CU 172, similar to events 340A and 342A respectively.

[0136] Now referring to Figures 4A - 4B , the UE 102 resumes the suspended radio connection with the non-aggregated base station and subsequently provides the preferred configuration to the CU of the non-aggregated base station. The CU may send the preferred configuration to the DU of the non-aggregated base station or release the preferred configuration.

[0137] First referring to Figure 4A , in the resume scenario 400A, the source base station (S-BS) 104B serves as the serving base station for the UE 102, similar to the serving base station 104A in scenario 300B. While in Figure 3BIn [description], UE 102 resumes the suspended radio connection with the same serving base station 104A and then provides a second preferred configuration to the serving base station 104A. In Figure 4A In a handover scenario, UE 102 resumes the suspended radio connection with the target base station (e.g., T-BS104A) and then provides a second preferred configuration to the target base station. In some implementations, Figure 4A The S-BS104B in [description] can be a distributed base station, just like the base station 104A in scenario 300B, and thus can perform operations similar to those of the Figure 3B CU 172 and DU 174 in [description] respectively. In another implementation, S-BS104B is an aggregated base station. In another implementation, S-BS104B and T-BS104A can share the same CU (i.e., T-CU 172), so S-BS104B and T-BS104A can be the same base station with two DUs. Therefore, in this implementation, there is no need to exchange the messages described below that are exchanged between S-BS104B and T-BS104A as separate base stations. For ease of explanation, in Figure 4A S-BS104B is described as an aggregated base station, and T-BS104A is described as a distributed base station including T-CU 172 and T-DU 174.

[0138] Initially, UE 102 operates in a connected state and communicates data 402A with S-BS104B through cell 124B using an S-BS configuration including multiple configurations (each configuration corresponding to respective configuration parameters), similar to event 302B.

[0139] Later, S-BS104B and UE 102 perform a 404A UE-assisted configuration procedure to enable UE 102 to send a preferred configuration to S-BS104B, similar to event 304B.

[0140] After UE 102 is able to send the preferred configuration, UE 102 and S-BS104B perform a UE-assisted information procedure 472A, similar to the UE-assisted information message procedure 372B, to provide the preferred configuration (i.e., the first preferred configuration) to S-BS104B.

[0141] In response to receiving the first preferred configuration from UE 102, S-BS104B performs a DU reconfiguration procedure 474A, similar to the DU reconfiguration procedure 374B, to generate a DU configuration (i.e., the first DU configuration), indicating a preferred maximum number not exceeding the SCell, MIMO layer, and / or aggregated bandwidth indicated in the first preferred configuration.

[0142] In some implementations, after generating the first DU configuration, S-BS104B and UE 102 perform an RRC reconfiguration procedure 476A, similar to the RRC reconfiguration procedure 376B. Thus, UE 102 can use the first DU configuration to update a plurality of configuration parameters previously provided by S-BS104B in event 402A, and communicate with S-BS104B using the updated configuration parameters.

[0143] At a later time (e.g., after S-BS104B detects that the traffic of UE 102 is inactive on the S-BS terminated radio bearer), S-BS104B determines to suspend the radio connection (e.g., including the RRC connection) between it and UE 102. In response to determining to suspend the radio connection, S-BS104B performs an RRC suspension procedure 478A, similar to the RRC suspension procedure 378B. Thus, UE 102 suspends the radio connection and can transition to an inactive state or an idle state.

[0144] In some implementations, if the configuration parameters in the S-BS configuration meet the first preferred configuration, S-BS104B does not need to generate the first DU configuration. In these implementations, S-BS104B does not need to perform the DU reconfiguration procedure 474A and the RRC reconfiguration procedure 476A before the RRC suspension procedure 478A. S-BS104B may not perform the DU reconfiguration procedure 474A and the RRC reconfiguration procedure 476A for other reasons, such as when S-BS104B is transmitting a large amount of data to UE 102, or when it is busy for other reasons.

[0145] At a later time, after suspending the radio connection, UE 102 can perform an RRC resume procedure 480A to transition from an inactive or idle state to a connected state. Opposed to UE 102 performing an RRC resume procedure 380B with the same serving base station 104A as described in Figure 3B Figure 4AThe UE 102 in [the relevant context] performs the RRC resume procedure 480A with the T-BS104A. In particular, during the RRC resume procedure 480A, the UE 102 sends a 430A RRC resume request message to the T-DU 174, which in turn sends a 432A RRC resume request message to the T-CU 172. Based on the RRC resume request message, the T-CU 172 addresses the S-BS104B (e.g., the source CU of the S-BS104B) and sends a 492A Retrieve UE Context Request message to the S-BS104B to retrieve the UE context of the UE 102. The S-BS104B sends a 494A Retrieve UE ContextResponse message including the first preferred configuration to the T-CU 174. The S-BS104B may also include the S-BS configuration in the Retrieve UE Context Response message. Then, the T-CU 172 may send a 496A UE context establishment request message including the first preferred configuration to the T-DU 174. In some implementations, if the Retrieve UE Context Response message includes the S-BS configuration, the T-CU 174 may include the S-DU configuration included in the S-BS configuration in the UE context establishment request message and send a 496A UE context establishment request message to the T-DU 174, enabling the T-DU 74 to generate a T-DU configuration, i.e., an incremental T-DU configuration that adds the S-DU configuration. In other implementations, the T-CU 172 omits the S-DU configuration to enable the T-DU 174 to generate a complete T-DU configuration (i.e., a fully self-contained T-DU configuration). Then, the T-DU 174 sends a 498A UE context establishment response message including the T-DU configuration to the T-CU 172.

[0146] In response to receiving the RRC resume request message in event 432A, the T-CU 172 sends a 434A RRC resume message including the T-DU configuration to the T-DU 174, which in turn sends a 436A RRC resume message to the UE 102, thus completing the RRC resume procedure 480A. As a result, the UE 102 resumes the suspended radio connection with the T-BS 104A and transitions to the connected state. The UE 102 may send a 440A RRC resume complete message to the T-DU 174, which in turn may send a 442A RRC resume complete message to the T-CU 172, similar to events 340B and 342B.

[0147] In some implementations, after the S-BS 104B and the UE 102 perform the RRC suspension procedure 478A, the UE 102 may retain the 454A first preferred configuration (e.g., in response to receiving an RRC suspension message during the RRC suspension procedure 478A). Similarly, in some implementations, the S-BS 104B may retain the 453A first preferred configuration in response to determining to suspend the radio connection with the UE 102. In other implementations, the UE 102 may retain the 454A first preferred configuration in response to initiating or during the RRC resume procedure 480A. Also, in some implementations, the S-BS 104B may retain the 453A first preferred configuration during the RRC resume procedure 480A.

[0148] As described above Figure 3B In some implementations, Figure 4A the UE 102 and the S-BS 104B in may release or retain some or all of the configurations in the S-BS configuration. Additionally, in some implementations, when the UE 102 is in the inactive state or the idle state, the UE 102 may retain the current security key, retain the ROHC state if the UE 102 is configured with ROHC, the QoS flow to DRB mapping rule, the C-RNTI used in the source PCell (e.g., PCell 124B), the cell identity and physical cell identity of the source PCcell, and other configuration parameters in the RLC configuration, the MAC configuration, and / or the physical layer configuration. In some implementations, when the UE 102 is in the inactive state or the idle state, the UE 102 may retain the fields or IEs that enable the UE 102 to send the first preferred configuration. In other implementations, in response to an RRC suspension message in the RRC suspension procedure 478A or during the RRC resume procedure 480A, the UE 102 may release the configuration in the ReconfigurationWithSync IE and / or the ServingCellConfigCommonSIB IE and / or the fields or IEs that enable the UE 102 to send the first preferred configuration.

[0149] After the UE 102 resumes the suspended radio connection 438A and transitions to the connected state, the UE 102 sends a 444A another UE assistance information message including another preferred configuration (i.e., the second preferred configuration) to the T-DU 174, similar to event 344B, for reasons similar to those described above regarding Figure 3BSimilar to the description. T-DU 174 then sends a 446A UE assistance information message to T-CU 172, similar to event 346B. By sending a second preferred configuration to T-CU 172, UE 102 can overwrite the first preferred configuration reserved on T-CU 172, so that when reconnecting to T-CU 171, UE 102 and T-CU 182 can communicate using the second preferred configuration. Then, T-CU 172 and T-DU 174 perform a 482A DU reconfiguration process, thus generating a second DU configuration, similar to process 382B, which causes T-CU 172 and UE 102 to perform a 484A RRC reconfiguration process, similar to RRC reconfiguration process 384B. Therefore, UE 102 can update multiple configuration parameters previously updated according to the first preferred configuration with the second DU configuration and communicate with T-DU 174 by using the updated configuration parameters.

[0150] Now refer to Figure 4B , in the recovery scenario 400B, S-BS104B operates as the serving base station of UE 102 again. While in Figure 4A , UE 102 and S-BS104B retain the first preferred configuration, and in Figure 4B , UE 102 and S-BS104B release the first preferred configuration. Generally, Figure 4B the S-BS 104B and T-BS104A in Figure 4A can respectively perform actions similar to those of the S-BS104B and T-BS104A in

[0151] Initially, UE 102 operates in the connected state and communicates 402B data with S-BS104B through cell 124B by using an S-BS configuration including multiple configurations (each configuration corresponding to a corresponding configuration parameter), similar to event 402A.

[0152] Later, S-BS104B and UE 102 perform a 404B A UE assistance configuration process to enable UE 102 to send a preferred configuration to S-BS104B, similar to event 404A.

[0153] After UE 102 is able to send the preferred configuration, UE 102 and S-BS104B perform a UE assistance information process 472B, similar to the UE assistance information message process 472A, thus providing the preferred configuration (i.e., the first preferred configuration) to S-BS104B.

[0154] In response to receiving a first preferred configuration from UE 102, S-BS 104B performs DU reconfiguration procedure 474B, similar to DU reconfiguration procedure 474A, to generate a DU configuration (i.e., the first DU configuration), indicating a preferred maximum number not exceeding the SCell, MIMO layers, and / or aggregated bandwidth indicated in the first preferred configuration.

[0155] In some implementations, after generating the first DU configuration, S-BS 104B performs an RRC reconfiguration procedure 476B with UE 102, similar to RRC reconfiguration procedure 476A. Thus, UE 102 can use the first DU configuration to update multiple configuration parameters previously provided by S-BS 104B in event 402B and communicate with S-BS 104B using the updated configuration parameters.

[0156] At a later time (e.g., after S-BS 104B detects that the traffic of UE 102 is inactive on the S-BS terminated radio bearer), S-BS 104B determines to suspend the radio connection (e.g., including the RRC connection) with UE 102. In response to determining to suspend the radio connection, S-BS 104B performs an RRC suspension procedure 478B, similar to RRC suspension procedure 478A. Thus, UE 102 suspends the radio connection and can transition to an inactive state or an idle state.

[0157] In some implementations, after S-BS 104B and UE 102 perform the RRC suspension procedure 478B, UE 102 may release 456B the first preferred configuration (e.g., in response to receiving an RRC suspension message during the RRC suspension procedure 478B). In other implementations, UE 102 may release 456B the first preferred configuration in response to initiating an RRC resume procedure 480B or during the RRC resume procedure 480B, as described below.

[0158] Subsequently, after suspending the radio connection, the UE 102 may perform an RRC resume procedure 480B to transition from an inactive or idle state to a connected state. In particular, during the RRC resume procedure 480B, the UE 102 sends an RRC resume request message 430B to the T-DU 174, which in turn sends an RRC resume request message to the T-CU 172. Based on the RRC resume request message, the T-CU 172 addresses the S-BS 104B and sends a retrieve UE context request message 492B to the S-BS 104B to retrieve the UE context of the UE 102. The S-BS 104B sends a retrieve UE context response message 494B including a first preferred configuration to the T-CU 172. The S-BS 104B may also include the S-BS configuration in the retrieve UE context response message. Then, the T-CU 172 releases the first preferred configuration 455B and sends a UE context establishment request message 496B (i.e., omitting the first preferred configuration) to the T-DU 174. In some implementations, if the retrieve UE context response message includes the S-BS configuration, the T-CU 172 may include the S-DU configuration included in the S-BS configuration in the UE context establishment request message and send a UE context establishment request message 496B to the T-DU 174, enabling the T-DU 74 to generate a T-DU configuration (i.e., an incremental T-DU configuration that adds the S-DU configuration). In other implementations, the T-CU 172 omits the S-DU configuration to enable the T-DU 174 to generate a complete T-DU configuration (i.e., a fully self-contained T-DU configuration). Then, the T-DU 174 sends a UE context establishment response message 498B including the T-DU configuration to the T-CU 172.

[0159] In response to receiving the RRC resume request message in event 432B, the T-CU 172 sends an RRC resume message 434B including the T-DU configuration to the T-DU 174, which in turn sends an RRC resume message 436B to the UE 102, thus completing the RRC resume procedure 480B. As a result, the UE 102 resumes the suspended radio connection with the T-BS 104A and transitions to the connected state. The UE 102 may send an RRC resume complete message 440B to the T-DU 174, and in turn may send a resume complete message 442B to the T-CU 172, similar to events 440A and 442A respectively.

[0160] By releasing the first preferred configuration at UE 102 and T-CU 172 at events 456B and 455B respectively, UE 102 and T-CU 174 are not required to communicate with each other according to the first preferred configuration when resuming a suspended radio connection. For example, UE 102 may have recovered from an overheating situation or a situation where the battery power has increased since the inactivity state or the idle state, such that UE 102 is able to utilize more SCell, MIMO layers, and / or aggregated bandwidth after transitioning back to the connected state than indicated in the first preferred configuration. For example, since UE 102 and T-CU 172 still know the S-BS configuration (including the updated configuration parameters configured by the RRC reconfiguration procedure 476B), UE 102 and T-CU 174 can continue to communicate using the S-BS configuration.

[0161] In some implementations, T-CU 172 may obtain another DU configuration (i.e., the second DU configuration) from T-DU 174, e.g., by using the UE context establishment procedure (as described above) Figure 4A and including the second DU configuration in the RRC resume message. In another such implementation, CU 172 may generate a configuration and include the generated configuration in the RRC resume message. In other implementations, after receiving the RRC resume complete message, T-CU 172 may obtain another DU configuration (i.e., the second DU configuration) from T-DU 174, e.g., by using a DU reconfiguration procedure (similar to the DU reconfiguration procedure 374A), and perform an RRC reconfiguration procedure with UE 102, similar to the RRC reconfiguration procedure 376A. CU 172 may include the second DU configuration in the RRC reconfiguration message during the RRC reconfiguration procedure. Since T-CU 172 releases the first preferred configuration at event 455B, T-CU 72 does not send the first preferred configuration to T-DU 174 during the DU reconfiguration procedure or the UE context establishment procedure. Thus, T-DU 174 generates the second DU configuration in a manner that does not underestimate the capabilities of UE 102, e.g., by considering UE capabilities rather than the first preferred configuration.

[0162] Now referring to Figures 5A - 5G , UE 102 is in DC with MN and SN and subsequently disconnects from SN. In various cases, UE 102 may release or retain the preferred configuration when disconnecting from SN.

[0163] First referring to Figure 5A, in scenario 500A, base station 104A operates as the MN for UE 102, and base station 106A operates as the SN for UE 102. In some implementations, SN 106A is a distributed base station including a CU and a DU, where the CU can exchange SN messages with MN 104A and exchange RRC messages with UE 102 through MN 104A, as described below. For ease of illustration, SN 106A is described as an aggregated base station. In this implementation, UE 102 releases the first preferred configuration upon SN release.

[0164] Initially, for example, UE 102 communicates 502A data with MN 104A in the SC through cell 124A using the MN configuration, similar to the BS configuration described above with respect to Figure 3A In other implementations and scenarios, UE 102 communicates 502A data with MN 104A in the DC through PCell 124A using the MN configuration and communicates with the source SN (S-SN) (e.g., with S-SN 106B through PSCell126B) in the DC using the S-SN configuration. In this case, Figure 5A the SN 106A shown in is the target SN (T-SN). In some implementations, during event 502A, MN 104A can receive the UE capabilities of UE 102 from UE 102, CN 110 (e.g., MME 114 or AMF 164), or another base station (e.g., base station 104B).

[0165] Later, for example, MN 104A blindly or in response to detecting an appropriate event determines 504A to initiate the SN addition procedure for communicating with SN 106A and UE 102. For example, the determination 504A can occur in response to MN 104A receiving one or more measurement results from UE 102 that are higher (or lower) than one or more predetermined thresholds or a filtered result calculated (from the measurement results) that is higher (or lower) than a predetermined threshold. In another example, the appropriate event can be that UE 102 is moving towards SN 106A. In yet another example, the appropriate event can be that one or more measurement results generated or obtained by MN 104A based on the measurement of the signal received from UE 102 are higher (or lower) than one or more predetermined thresholds. In yet another example, the determination 504A can occur in response to MN 104A receiving an SN change request message from the S-SN (e.g., S-SN 106B).

[0166] After determining to initiate the SN addition process, MN 104A sends a SN addition request message 506A including the UE capabilities of UE 102 to SN 106A. Further, SN 106A can generate a DU configuration (i.e., the first DU configuration) in a manner not exceeding the capabilities of UE 102, e.g., by considering the UE capabilities. In some implementations, if SN 106A is a T-SN, MN 104A can also include in the SN addition request message an S-SN configuration associated with an S-SN (e.g., S-SN 106B).

[0167] If SN 106A is a distributed base station composed of a CU and a DU, in response to receiving the SN addition request message, the CU sends a UE context establishment request message to the DU to obtain the first DU configuration of UE 102. In response to the UE context establishment request message, the DU sends a UE context establishment response message including the first DU configuration to the CU. The CU can include the UE capabilities in the UE context establishment request message, and the DU can generate the first DU configuration in a manner not exceeding the UE capabilities. In some implementations, the CU can include an S-SN configuration or an S-DU configuration in the S-SN configuration of the UE context establishment request message. The DU can generate the first DU configuration as an incremental DU configuration, adding a part of the S-SN configuration or the S-DU configuration. In other implementations, the DU can generate the first DU configuration as a complete DU configuration, which is a complete and self - contained DU configuration. The first DU configuration and the S-DU configuration are similar to Figure 3A the DU configuration described above.

[0168] In response to receiving a SN Addition Request message, SN 106A sends a SN Addition Request Acknowledge message including a first DU configuration to MN 104A. Further, MN 104A sends a RRC container message including the first DU configuration to UE 102. In response to the RRC container message, UE 102 sends a RRC container response message to MN 104A and then sends a SN Reconfigration Complete message to SN 106A. In some implementations, SN 106A generates a RRC reconfiguration message including the first DU configuration, includes the RRC reconfiguration message in the SN addition request acknowledge message, and sends the SN addition request acknowledge message information to MN 104A. Further, MN 104A sends a RRC container message including the RRC reconfiguration message to UE 102. In some implementations, UE 102 may include a RRC reconfiguration complete message in the RRC container response message, and then MN 104A includes the RRC reconfiguration complete message in the SN reconfiguration complete message in event 520A. In some implementations, SN 106A may include a measurement configuration (e.g., MeasConfig IE) in the RRC reconfiguration message.

[0169] In an implementation where MN 104A receives a SN change request message from an S-SN (e.g., S-SN 106B), in response to the SN change request message, e.g., before or after receiving the RRC container response message or the SN addition request acknowledge message, MN 104A may send a SN change confirmation message to the S-SN. In some implementations, after determining to initiate the SN addition process at 504A, MN 104A may send a SN release request message to the S-SN. The S-SN may send a SN release request acknowledgement message as a response to MN 104A.

[0170] In some implementations, SN 106A (e.g., the CU of SN 06A) may generate a CU configuration. For example, the CU configuration may be a Radio Bearer Configuration (RadioBeareConfig IE). At event 516A, SN 106A may include the CU configuration in the SN addition request confirmation message, and at event 517A, MN 104A may include the CU configuration in the RRC container message. The CU configuration may be a complete CU configuration, which is a fully self - contained CU configuration, or an incremental CU configuration that adds to the source CU configuration (e.g., RadioBeareConfig IE) in the S - SN configuration.

[0171] The above - mentioned first DU configuration or RRC re - configuration message also includes one or more random access configurations required for the UE 102 to connect to SN 106A (e.g., the DU of SN 106A), and in some implementations, also includes other fields, such as a mobility field (e.g., the mobilityControlInfoSCG field or ReconfigurationWithSync IE), which may include part or all of the random access configuration.

[0172] In response to receiving the 517A first DU configuration or RRC re - configuration message, UE 102 performs a 522A random access procedure with SN 106A (e.g., the DU of SN106A), for example, by using one or more random access configurations in the first DU configuration or RRC re - configuration message. After SN 106A (e.g., the DU of SN 106A) identifies UE 102 during the random access configuration (e.g., UE 102 successfully resolves contention), UE 102 communicates 526A control signals and data with MN 104A and SN 106B (e.g., the DU of SN106A) in DC by using the first DU configuration. In an implementation where MN 104A includes the CU configuration in the RRC container message at event 517A, UE 102 may communicate 526A data with SN 106A (e.g., the CU of SN 106A) by using the complete CU configuration or the incremental CU configuration and a part of the source CU configuration. After SN 106A (e.g., the DU of SN06A) identifies UE 102 during the random access configuration (e.g., UE 102 successfully resolves contention), in response to the DU of SN 106 identifying UE 02 during random access, a downlink data transfer status message may be sent to the CU of SN 106A. Events 504A, 506A, 516A, 512A, 518A, 520A, 522A, and 526A are Figure 5A collectively referred to as the DC configuration process 560A.

[0173] After the UE 102 connects to the SN 106A in event 522A, the MN 104A or the SN 106A may initiate a UE-assisted configuration procedure 528A with the UE 102 to enable the UE 102 to send a preferred configuration, similar to event 304A. In the UE-assisted configuration procedure initiated by the MN, the MN 104A configures the UE 102 to indirectly provide the preferred configuration to the SN 106A through the MN 104A. In the UE-assisted configuration procedure initiated by the SN, the SN 106A may configure the UE 102 to directly provide the preferred configuration to the SN 106A or indirectly provide the preferred configuration to the SN 06A through the MN 104A.

[0174] For example, in some implementations, in the UE-assisted configuration procedure initiated by the SN, the SN 106A may send an RRC message to the UE 102 through the MN 104A or broadcast an RRC message through the PSCell 126A to enable the UE 102 to send a preferred configuration. Subsequently, the UE 102 may send an RRC response message to the SN 106A through the MN 104A. In other implementations, the SN 106A may include a field / IE in the RRC reconfiguration message in event 516A to enable the transmission of the preferred configuration.

[0175] If the UE capability indicates support for sending the preferred configuration to the SN 106A, the SN 106A may enable the UE 102 to send the preferred configuration. In some implementations, the UE 102 may indicate support for sending the preferred configuration to the SN 106A in the capability IE of the SN 106A. For example, if the SN 106A is a gNB, the capability IE is UE-NR-Capability or UE-MRDC-Capability. If the SN 106A is an ng-eNB, the capability IE is UE-EUTRA-Capability or UE-MRDC-Capability. In some implementations, the UE 102 may indicate support for sending the preferred configuration to the SN 106A in the capability IE of the MN 104A.

[0176] If the UE capability does not indicate support for sending the preferred configuration to SN 106A, then SN 106A cannot cause UE 102 to send the preferred configuration to SN 06A. For example, if the UE capability indicates support for sending the preferred configuration only to MN 104A, then SN 106A cannot cause UE 102 to send the preferred configuration to SN 106A. In some implementations, UE 102 may support sending the preferred configuration to MN 104A in the capability IE of MN 104A. For example, if MN 104A is a gNB, the capability IE is UE-NR-Capability. If MN is an eNB or ng-eNB, the capability IE is UE-EUTRA-Capability. In some implementations, UE 102 may indicate support for indirectly sending the preferred configuration to SN 106A through MN 104A in the capability IE of MN 104A. For example, if MN 104A is a gNB, the capability IE is UE-NR-Capability. If MN is an eNB or ng-eNB, the capability IE is UE-EUTRA-Capability.

[0177] In some implementations, SN 106A may send an RRC reconfiguration message to UE 102 through MN 104A to selectively update the first DU configuration (e.g., add a new configuration to the first DU configuration or modify the configuration in the first DU configuration). In response, UE 102 may send an RRC reconfiguration complete message to SN 106A through MN 104A. For simplicity, Figure 5A the first DU configuration described in

[0178] After the UE 102 is able to send the preferred configuration, the UE 102 sends a UE assistance information message including the first preferred configuration to the MN 104A. In various scenarios and implementations, the UE 102 may send the first preferred configuration for different reasons. In one implementation, as described in event 526A (i.e., the configuration parameters do not meet the preferences of the UE 102 defined in the first preferred configuration), if the UE 102 is not satisfied with the configuration parameters in the first DU configuration used by the UE 102 to communicate with the SN 106A, the UE 102 may send the first preferred configuration. In another implementation, even if the UE 102 is satisfied with the configuration parameters, the UE 102 may send the first preferred configuration to prevent the SN 106A from changing the configuration parameters that the UE 102 may not like. In certain implementations, if the UE 102 experiences an overheating situation (e.g., due to heavy application process handling), detects low battery power, or determines to conserve energy, the UE 102 may send the first preferred configuration. The UE 102 may send the first preferred configuration for energy conservation purposes (even if the UE 102 does not experience an overheating situation), overheating purposes, or both purposes.

[0179] In response to receiving the 532A UE assistance information message from the UE 102, the MN 104A then sends a 534A UE assistance information message to the SN 106A. Events 532A and 534A are in Figure 5ACollectively referred to as the UE assistance information procedure 530A in the present disclosure. In some implementations, if SRB3 between UE 102 and SN 106A is not configured, UE 102 may send a ULInformationTransferMRDC message 532A including a UE assistance information message to MN 104A via SRB1. In some implementations, if SRB3 between UE 102 and SN 106A is configured and not suspended, UE 102 may send a UE assistance information message 531A to SN 106A via SRB3 instead of sending a UE assistance information message to SN 06A via MN 104A (events 532A and 534A). In other implementations, if SRB3 between UE 102 and SN 106A is configured and suspended, UE 102 may send a ULInformationTransferMRDC message 532A including a UE assistance information message to MN 104A via SRB1. In this case, UE 102 cannot send a ULInformationTransferMRDC message including a MeasurementReport message associated with the measurement configuration configured with SN 106A to MN 104A via SRB1. In other implementations, if SRB3 between UE 102 and SN 106A is configured and suspended, UE 102 may suspend the transmission of the UE assistance information message (i.e., UE 102 neither sends a UE assistance information message to MN 104A nor to SN 106A). After SRB3 is resumed, if UE 102 determines that the conditions for sending the UE assistance information message are still met, UE 102 may send a UE assistance information message to SN 106A on SRB3. After SRB2 is resumed, if UE 102 determines that the conditions for sending the UE assistance information message are not met, UE 102 abandons the transmission of the UE assistance information message. If UE 102 has generated a UE assistance information message and determines that the conditions for sending the UE assistance information message are not met, UE 102 may discard the UE assistance information message.

[0180] In response to receiving the UE assistance information message, SN 106A then generates a second DU configuration 536A in response to receiving the first preferred configuration, similar to the base station 104A in the above regarding Figure 3AThe manner of generating the DU configuration in the DU reconfiguration procedure 374A. That is, in the embodiment where the SN 106A is a distributed base station, the CU of the SN 106A sends a first interface message including a first preferred configuration to the DU of the SN 106B, the DU generates a second DU configuration, and the DU sends the second DU configuration to the CU in the second interface message. In some implementations, the SN 106A may omit the second DU configuration in the second interface message, or may include a second DU configuration unrelated to the first preferred configuration in the second interface message, similar to the manner in which the base station 104A omits the DU configuration or includes a DU configuration unrelated to the first preferred configuration in the second interface message of the DU reconfiguration procedure 374A.

[0181] In some implementations, after generating the second DU configuration, the SN 106A sends an RRC reconfiguration message 538A including the second DU configuration to the MN 104A, and then sends an RRC reconfiguration message 540A to the UE 102. In response, the UE 102 may send an RRC reconfiguration complete message 542A to the MN 104A, and then send an RRC reconfiguration complete message 544A to the SN 106A. Therefore, the UE 102 can update multiple configuration parameters previously provided by the SN 106A in the first DU configuration using the second DU configuration, and communicate with the SN 106A (e.g., the DU of the SN 106B) by using the updated configuration parameters. In some implementations, the SN 106A may send an SN message (e.g., an SN modification request message, an SN modification request confirmation message, or an RRC transmission message) including an RRC reconfiguration message to the MN 104A, and then may send an RRC container message 540A including an RRC reconfiguration message to the UE 102. Then, the UE 102 may send an RRC container response message 542A including an RRC reconfiguration complete message to the MN 104A, and then may send an SN message (e.g., an SN modification request message, an RRC transmission message, or an SN reconfiguration complete message) 544A including an RRC reconfiguration complete message to the SN 106A. Events 538A, 540A, 542A, and 544A are collectively referred to as the RRC reconfiguration procedure 570A in Figure 5A are collectively referred to as the RRC reconfiguration procedure 570A.

[0182] Although the SN 106A is described as generating one second DU configuration at event 536A, the SN 106A may generate multiple second DU configurations. If the SN 106A generates multiple second DU configurations, the SN 106A and the UE 102 may perform the RRC reconfiguration procedure 570A multiple times, so that the UE 102 can obtain multiple second DU configurations.

[0183] As described above, in some implementations, in response to receiving the first preferred configuration 534A, the SN 106A does not need to generate the second DU configuration. In these implementations, the SN 106A does not need to perform the DU reconfiguration process 536A and the RRC reconfiguration process 570A before the SN release process 546A. The SN 106A does not need to perform the DU reconfiguration process 536A and the RRC reconfiguration process 570A for other reasons, for example, when the SN 106A transmits a large amount of data to the UE 102 or is busy in other aspects.

[0184] In some scenarios and implementations, after receiving the first preferred configuration at event 530A, the SN 106A may generate a C-DU configuration, similar to Figure 3A the way the base station 104A generates a DU configuration in the DU reconfiguration process 374A, to prepare a conditional configuration for adding or changing (CPAC) the conditional PSCell of the UE 102. The SN 106A may generate a C-DU configuration that meets the first preferred configuration. In other scenarios and implementations, whether before or after event 530A, the SN 106A may generate a C-DU configuration according to the UE capabilities stored in the SN 106A, without considering the first preferred configuration. After the SN 106A obtains the C-DU configuration, the SN 106A generates an RRC message including the C-DU configuration, a conditional configuration including the RRC message, and an RRC reconfiguration message including the conditional configuration. Then, the SN 106A sends the RRC reconfiguration message to the UE 102 through the MN 104A or an SRB (such as SRB3). Subsequently, if the UE 102 detects that the conditions for the candidate cell to connect to the SN 106A are met, the UE 102 connects to the SN 106A through the candidate cell (i.e., the candidate PSCell). The SN 106A may perform an RRC reconfiguration process with the UE 102 through the MN 104A or an SRB to send another DU configuration that meets the first preferred configuration to the UE 102, similar to the DU reconfiguration process 536A or 536B and the RRC reconfiguration process 570A or 571B.

[0185] In one implementation, if SN 106A sends a conditional configuration (i.e., the first conditional configuration) to UE 102 before receiving the first preferred configuration from UE 102, SN 106A will not update the conditional configuration even if the conditional configuration does not meet the first preferred configuration. In another implementation, if the conditional configuration does not meet the first preferred configuration, SN 106A may send an RRC reconfiguration message to UE 102 via MN 104A or an SRB to release the conditional configuration. In another implementation, CU 172 may send an RRC reconfiguration message to UE 102 via MN 104A or an SRB to release the conditional configuration in response to receiving the first preferred configuration from UE 102. In another implementation, if the conditional configuration does not meet the first preferred configuration received from UE 102, SN 106A may send an RRC reconfiguration message including another conditional configuration (i.e., the second conditional configuration) to UE 102 via MN 104A or an SRB to replace the first conditional configuration. SN 106A may obtain a new C-DU configuration that meets the first preferred configuration and send the second conditional configuration including the new C-DU configuration to UE 102 in a similar manner as described above.

[0186] In some scenarios and implementations, UE 102 may be in SC with MN 104A or in DC with MN 104A and SN106A, as Figure 5A shown. After receiving the first preferred configuration from UE 102, MN 104A may perform a conditional DC configuration process (i.e., CSAC configuration process) with a candidate SN (C-SN) (e.g., C-SN 106B) and UE 102, similar to the DC configuration process 560A, and send a conditional configuration of CSAC to UE 102. MN 104A may include the first preferred configuration in the SN addition request message during the CSAC configuration process. Then, the C-SN may generate a C-DU configuration that meets the first preferred configuration and generate an RRC reconfiguration message including the C-DU configuration. The C-SN may send an SN addition request confirmation message including the RRC reconfiguration message to MN 104A in response to the SN addition request message. Further, MN 104A generates a conditional configuration including the RRC reconfiguration message and sends an RRC container message including the conditional configuration to UE 102.

[0187] In other scenarios and implementations, UE 102 may be in SC with MN 104A or in DC with MN 104A and SN106A, as Figure 5AAs shown. Before or after receiving the first preferred configuration, MN 104A can perform a CSAC configuration process with C-SN (such as C-SN 106B) and UE 102, similar to the DC configuration process 560A, to send a conditional configuration of CSAC to UE 102. MN 104A can send an SN addition request message that does not include the first preferred configuration during the CSAC configuration process. Then, the C-SN can generate a C-DU configuration according to the UE capabilities and generate an RRC reconfiguration message including the C-DU configuration. The C-SN can send an SN addition request confirmation message including the RRC reconfiguration message to MN 104A in response to the SN addition request message. Further, MN 104A generates a conditional configuration including the RRC reconfiguration message and sends an RRC container message including the conditional configuration to UE 102. Subsequently, if UE 102 detects that the conditions for a candidate cell connected to the C-SN are met, UE 102 connects to the C-SN through the candidate cell (i.e., the candidate PSCell). If the C-SN receives the first preferred configuration from UE 102 or MN 104A, the C-SN can perform an RRC reconfiguration process with UE 102 through MN 104A or SRB to send another DU configuration that meets the first preferred configuration to UE 102, similar to the DU reconfiguration process 536A or 536B and the RRC reconfiguration process 570A or 571B.

[0188] In one implementation, if MN 104A sends a conditional configuration (i.e., the first conditional configuration) to UE 102 before receiving the first preferred configuration from UE 102, MN 104A will not update the conditional configuration even if the conditional configuration does not meet the first preferred configuration. In another implementation, if the conditional configuration does not meet the first preferred configuration, MN 104A can send an RRC container message to UE 102 to release the conditional configuration. In another implementation, MN 104A can send an RRC container message to UE 102 to release the conditional configuration in response to receiving the first preferred configuration from UE 102. In another implementation, if the conditional configuration does not meet the first preferred configuration received from UE101, MN 104A can send an RRC container message including another conditional configuration (i.e., the second conditional configuration) to UE 102 to replace the first conditional configuration. MN 104A can obtain an RRC reconfiguration message including a new C-DU configuration that meets the first preferred configuration from the C-SN and send a second conditional configuration including the RRC reconfiguration information to UE 102 in a similar manner as described above.

[0189] At a later time (e.g., after MN 104A or SN 106A detects that the traffic of UE 102 is inactive on the SN terminated radio bearer), MN 104A or SN 106A determines to release SN 106A of UE 102. During the MN initiated SN release procedure, MN104A may initiate a 546A SN release procedure with SN 106A to release SN 106A of UE 102 (i.e., configure UE 102 to be in SC). MN 104A sends an SN release request message to SN 106A, and in turn SN 106A sends an SN release request confirmation message to MN 104A. Optionally, during the SN initiated SN release procedure, SN 106A may initiate a 546A SN release procedure with MN 104A to release SN 106A of UE 102. SN 106A sends an SN release requirement message to MN 104A, and in turn MN 104A sends an SN release confirmation message to SN 106A. After MN 104A or SN 106A determines to release SN 106A, MN 104A sends an RRC reconfiguration message to UE 102548A indicating the release of SN 106B. That is, during the MN initiated SN release procedure or the SN initiated SN release procedure, MN 104A may send a 548A RRC reconfiguration message to UE 102. As a result, UE 102 disconnects 550A from SN 106A and releases the first preferred configuration in response to the release of SN 106A. Since the second DU configuration received at event 540A is unnecessary as a result of disconnecting 550A from SN 106A, UE 102 also releases the second DU configuration. Then, UE 102 sends a 552A RRC reconfiguration complete message to MN 104A in response to the RRC reconfiguration message. Thus, UE 102 in SC communicates 554A with MN 104A after disconnecting from SN 106A.

[0190] In some implementations, in response to receiving an RRC reconfiguration message at event 548A or in response to releasing SN 106A, UE 102 may release or retain some or all of the configurations in the second DU configuration. If there are configurations in the first DU configuration that are not updated by the second DU configuration, UE 102 may also release the configurations in the first DU configuration in response to the RRC reconfiguration message at event 548A or in response to releasing SN 106A. In some implementations, in response to receiving an RRC reconfiguration message at event 548A or in response to releasing SN 106A, UE 102 may release configurations in the ReconfigurationWithSync IE and / or ServingCellConfigCommonSIB IE, and / or release or retain fields or IEs that enable UE 102 to send the first preferred configuration. In some implementations, if UE 102 receives fields or IEs that enable UE 102 to send the first preferred configuration during a UE-assisted configuration procedure initiated by the MN, then in response to receiving an RRC reconfiguration message at event 548A or in response to releasing SN 106A, UE 102 may retain the fields or IEs. In other implementations, if UE 102 receives fields or IEs that enable UE 102 to send the first preferred configuration during a UE-assisted configuration procedure initiated by the SN, then in response to receiving an RRC reconfiguration message at event 548A or in response to releasing SN 106A, UE 102 may release the fields or IEs.

[0191] In some implementations, if MN 104A is a gNB, the RRC container message may be an RRCReconfiguration message and the RRC container response message may be an RRCReconfigurationComplete message. In other implementations, if MN 104A is an eNB or ng-eNB, the RRC container message may be an RRCConnectionReconfiguration message and the RRC container response message may be an RRCConnectionReconfigurationComplete message.

[0192] In some implementations, if SN 106A is a gNB, the RRC reconfiguration message and the RRC reconfiguration complete message can be the RRCReconfiguration message and the RRCReconfigurationComplete message, respectively. In other implementations, if SN 106B is an eNB or an ng-eNB, the RRC reconfiguration message and the RRC reconfiguration complete message can be the RRCConnectionReconfiguration message and the RRCConnectionReconfigurationComplete message, respectively.

[0193] Now referring to Figure 5B , in scenario 500B, base station 104A operates as the MN of UE 102 again, and base station 106A operates as the SN of EU 102 again. And in Figure 5A , UE 102 sends a first preferred configuration to SN 106A via MN 104A, and in Figure 5B , UE 102 sends the first preferred configuration directly to SN 106A. Accordingly, SN 106A sends a second DU configuration directly to UE 102.

[0194] Initially, UE 102 communicates 502B data with MN 104A in the SC via cell 124A by using the MN configuration, similar to event 502A. Later, MN 104A performs a DC configuration procedure 560B, similar to the DC configuration procedure 590A. As a result, UE 102 sends control signals and data in the DC with MN 104A and SN 106A (e.g., the DU of SN 106A) by using the first DU configuration received from MN 104A during the DC configuration procedure 560B.

[0195] After UE 102 is connected to SN 106A, MN 104A or SN 106A can initiate 528B a UE-assisted configuration procedure with UE 102, similar to event 528A, to enable UE 102 to send a preferred configuration directly to SN 106A. After UE 102 is able to send a preferred configuration, UE 102 performs a UE-assisted information procedure 531B by sending a UE-assisted information message including the first preferred configuration directly to SN 106A for different reasons in different scenarios and implementations, as described above with respect to Figure 5A . Then, in response to receiving the first preferred configuration, SN 106A generates 536B a second DU configuration, similar to event 536A.

[0196] In some implementations, after generating the second DU configuration, SN 106A directly sends an RRC reconfiguration message 539B including the second DU configuration to UE 102. In response, UE 102 may directly send an RRC reconfiguration complete message 543B to SN 106A. The SRB3 resource may enable UE 102 and SN 106A to exchange the RRC reconfiguration message and the RRC reconfiguration complete message. Therefore, UE 102 may use the second DU configuration to update multiple configuration parameters previously provided by SN 106A during the DC configuration procedure 560B in the first DU configuration, and communicate with SN 106A by using the updated configuration parameters. Events 539B and 543B are collectively referred to as the RRC reconfiguration procedure 571B in Figure 5B which is collectively referred to as the RRC reconfiguration procedure 571B.

[0197] At a later time (e.g., after MN 104A or SN 106A detects that the traffic of UE 102 is inactive on the SN-terminated radio bearer), MN 104A or SN 06A may initiate an SN release procedure 546B to release SN 106A in UE 102, similar to event 546A. After MN 104A or SN 106A determines to release SN 106A, MN 104A sends an RRC reconfiguration message 548B to UE 102, indicating the release of SN 06A, similar to event 548A. As a result, UE 102 disconnects 550B from SN 106A and releases the first preferred configuration in response to the release of SN 106A, similar to event 550A. Then, UE 102 sends an RRC reconfiguration complete message 552B to MN 104A in response to the RRC reconfiguration message, similar to event 552A. Therefore, after disconnecting from SN 106A, UE 102 performs SC communication 554B with MN 104A, similar to event 554A.

[0198] Now referring to Figure 5C , in scenario 500C, base station 104A operates again as the MN of UE 102, and base station 106A operates again as the SN of EU 102. While in Figure 5A or Figure 5B , MN 104A or SN 106A initiates the SN release procedure independently of the first preferred configuration received from UE 102. In Figure 5C , UE 102 notifies SN 106A to initiate the SN release procedure by sending the first preferred configuration to SN 106A.

[0199] Initially, UE 102 communicates 502C data with MN 104A in the SC via cell 124A using the MN configuration, similar to event 502A. Later, MN 104A performs a DC configuration procedure 560C, similar to the DC configuration procedure 590A. As a result, UE 102 communicates control signals and data with MN 104A and SN 106A in the DC by using the first DU configuration received from MN 104A during the DC configuration procedure 560C.

[0200] After UE 102 connects to SN 106A, either MN 104A or SN 106A can initiate 528C a UE-assisted configuration procedure with UE 102, similar to event 528A, to enable UE 102 to send a preferred configuration. After UE 102 is able to send the preferred configuration, UE 102 performs a UE-assisted information procedure 530C, similar to event 530A or 531B, thereby providing a first preferred configuration to SN 106A. In some implementations, the first preferred configuration generated by UE 102 may include an indication for releasing SN 106A. For example, if SN 106A is a 5G base station, such as a gNB, the first preferred configuration includes an indication to disable 5G. As another example, the first preferred configuration includes a zero SCell indication associated with SN 106A. For example, the indication may be a reducedCCsDL and / or a reducedCCsUL field. In one implementation, in the first preferred configuration or the UE-assisted information message, UE102 may include a reducedCCsDL field with a value of "0" to indicate a zero SCell associated with SN 106A. In this implementation, UE 102 may or may not include a reducedCCsUL field in the first preferred configuration or the UE-assisted information message. If UE 102 includes a reducedCCsUL field, it may have a value of "0" or a non-"0" value. If SN 106A receives a reducedCCsDL field with a value of "0" and a reducedCCsUL field with a non-"0" value, SN 106A may determine based on the reducedCCsDL field that UE 102 indicates a zero SCell associated with SN 106A and ignore the reducedCCsUL field. After receiving the first preferred configuration, SN 106A determines 537C to perform an SN release procedure in response to the first preferred configuration, rather than generating a second DU configuration as in event 536A or 536B.

[0201] Therefore, SN 106A can initiate the 546C SN release procedure to release the SN 106A of UE 102. After SN 106C determines to release SN 106B, MN 104A sends an RRC reconfiguration message to 548C, indicating the release of SN 106A, similar to event 548A. As a result, UE 102 disconnects from SN 106A at 550C and releases the first preferred configuration in response to the release of SN 106A, similar to event 550A. Then, in response to the RRC reconfiguration message, UE 102 sends a 552C RRC reconfiguration complete message to MN 104A, similar to event 552A. Therefore, after disconnecting from SN 106A, UE 102 communicates with MN 104A in the SC at 554C, similar to event 554A.

[0202] Now refer to Figure 5D , in scenario 500D, base station 104A operates as the MN of UE 102 again, and base station 106A operates as the SN of UE 102 again. While in Figure 5A , UE 102 releases the first preferred configuration in event 550A, and in Figure 5D , UE 102 retains the first preferred configuration.

[0203] Initially, UE 102 communicates data with MN 104A in the SC through cell 124A by using the MN configuration, similar to event 502A. Later, MN 104A performs the DC configuration procedure 560D, similar to the DC configuration procedure 590A. As a result, UE 102 communicates control signals and data with MN 104A and SN 106A in the DC by using the first DU configuration received from MN 104A during the DC configuration procedure 560D.

[0204] After UE 102 connects to SN 106A, while in Figure 5A , MN 104A or SN 106A can initiate the 528A UE-assisted configuration procedure, and in Figure 5D , only MN 104A can initiate the 528D UE-assisted establishment procedure to enable UE 102 to send the preferred configuration. After UE 102 is able to send the preferred configuration, UE 102 performs the UE-assisted information procedure 530D by sending a UE-assisted information message including the first preferred configuration to SN 106A through MN 104A for different reasons in different scenarios and implementations, as described above regarding Figure 5A . Then, in response to receiving the first preferred configuration, SN 106A generates the second DU configuration 536D, similar to event 536A.

[0205] In some implementations, after generating the second DU configuration, SN 106A and UE 102 perform an RRC reconfiguration procedure 570D, similar to event 570A or 571B. Thus, UE 102 can update multiple configuration parameters previously provided by SN 106A during the DC configuration procedure 560D in the first DU configuration with the second DU configuration, and communicate with SN 106A by using the updated configuration parameters.

[0206] At a later time (e.g., after MN 104A or SN 106A detects that the traffic of UE 102 is inactive on the SN-terminated radio bearer), MN 104A or SN 06A can initiate a 546D SN release procedure to release SN 106A in UE 102, similar to event 546A. After MN 104A or SN 106A determines to release SN 106A, MN 104A sends an RRC reconfiguration message 548D to UE 102, indicating the release of SN 06A, similar to event 548A. As a result, UE 102 disconnects from SN 106A 550D, similar to event 550A, but retains the first preferred configuration in response to the release of SN 106A. Then, in response to the RRC reconfiguration message, UE102 sends a 552D RRC reconfiguration complete message to MN 104A, similar to event 552A. Thus, after disconnecting from SN 106A, UE 102 performs SC communication 554D with MN 104A, similar to event 554A.

[0207] At a later time, UE 102 can send a 556D another UE assistance information message including another preferred configuration (i.e., the second preferred configuration) to MN 104A, similar to the way UE 102 sends the 344B second preferred configuration to the DU 174 of base station 104A as discussed above with respect to Figure 3B By sending the second preferred configuration to MN 104A, UE 102 can overwrite the first preferred configuration retained at MN 104A during the UE assistance information procedure 530D, so that UE 102 and MN 104B can subsequently communicate using the second preferred configuration. MN 104A can also store the 558D second preferred configuration. In some implementations, MN 104A can release the first preferred configuration in event 558D. In other implementations, MN 104A can store preferred parameters where the second preferred configuration remains unchanged in event 558D.

[0208] UE 102 can send the 556D second preferred configuration for the same reasons as those described above with respect to Figure 3BSimilar to the above. In a specific example, UE 102 may send a second preferred configuration to adjust (e.g., increase or decrease) the number of SCell associated with SN 106A indicated in the first preferred configuration, or release the first preferred configuration. Thus, since MN 104A may store the second preferred configuration, if MN 104A subsequently determines to perform a DC configuration process, MN 104B may adapt to the preference of UE 102 related to SN 106A, similar to event 560D.

[0209] Now refer to Figure 5E , in scenario 500E, base station 104A operates as the MN of UE 102 again, and base station 106A operates as the SN of UE 102 again. While in Figure 5C , UE 102 disconnects from SN 106A and releases the first preferred configuration, and in Figure 5E , UE 102 disconnects from SN 106A and retains the first preferred configuration.

[0210] Initially, similar to event 502C, UE 102 communicates 502E data with MN 104A in the SC through cell 124A using the MN configuration. Later, MN 104A performs a DC configuration process 560E, similar to the DC configuration process 590C. As a result, UE 102 communicates control signals and data with MN 104A and SN 106A in the DC by using the first DU configuration received from MN 104A during the DC configuration process 560E.

[0211] After UE 102 connects to SN 106A, while in Figure 5C , MN 104A or SN 106A may initiate a 528C UE-assisted configuration process, and in Figure 5E , only MN 104A can initiate a 528E UE-assisted configuration process, similar to event 528D, to enable UE 102 to send a preferred configuration. After UE 102 is able to send a preferred configuration, UE 102 performs a UE-assisted information process 530E, similar to event 530D, thereby providing the first preferred configuration to SN 106A. In some implementations, the first preferred configuration generated by UE 102 may include an indication for releasing SN 106A. For example, if SN 106A is a gNB, the first preferred configuration includes an indication for disabling 5G. As another example, the first preferred configuration includes an indication of zero SCell associated with SN 106A (e.g., the reducedCCsDL and / or reducedCCsUL fields discussed above). After receiving the first preferred configuration, in response to the first preferred configuration, SN 106A determines to perform a SN release process 537E, similar to event 537C.

[0212] Therefore, SN 106A can initiate a 546E SN release procedure to release SN 106A of UE 102, similar to event 546C. After SN 106A determines to release SN 106A, MN 104A sends a 548E RRC reconfiguration message to UE 102, indicating the release of SN 106B, similar to event 548C. As a result, UE 102 disconnects from SN 106A at 550E, similar to event 550D, but retains the first preferred configuration in response to the release of SN 106A. Then, in response to the RRC reconfiguration message, UE 102 sends a 552E RRC reconfiguration complete message to MN 104A, similar to event 552D. Therefore, after disconnecting from SN 106A, UE 102 performs SC communication with MN 104A at 554E, similar to event 554D.

[0213] Later, UE 102 can send a 556E another UE assistance information message (i.e., the second preferred configuration) including another preferred configuration to MN 104A, similar to event 556D. By sending the second preferred configuration to MN 104A, UE 102 can overwrite the first preferred configuration retained at MN 104A during the UE assistance information procedure 530E, so that UE 102 and MN 104B can subsequently communicate using the second preferred configuration. UE 102 can send the 556E second preferred configuration for reasons similar to those described above with respect to Figure 5D MN 104A can also store the 558E second preferred configuration, similar to event 558D.

[0214] Now referring to Figure 5F , in scenario 500F, base station 104A operates as the MN of UE 102 again, and base station 106A operates as the SN of EU 102 again. And in Figure 5D , in event 536D, SN 106A is able to receive a UE Assistance Information message including the first preferred configuration from MN 104A to generate a second DU configuration. In Figure 5F , SN 106A is a legacy base station that cannot interpret the UE Assistance Information message. To provide the first preferred configuration to the legacy SN 106A, MN 104A can send the first preferred configuration to SN 106A through an SN modification request message.

[0215] Initially, UE 102 communicates data 502F with MN 104A in SC via cell 124A using the MN configuration, similar to event 502D. Later, MN 104A performs a DC configuration procedure 560F, similar to the DC configuration procedure 590D. As a result, UE 102 communicates control signals and data with MN 104A and SN 106A in DC using the first DU configuration received from MN 104A during the DC configuration procedure 560D.

[0216] After UE 102 connects to SN 106A, MN 104A initiates 528F a UE-assisted configuration procedure to enable UE 102 to send a preferred configuration, similar to event 528D. After UE 102 is able to send a preferred configuration, UE sends 532F a UE-assisted information message including the first preferred configuration to MN 104, similar to event 532A. Further, MN 104A converts 533F the first preferred configuration into an IE that SN 106A can read. For example, the IE can be the ConfigRestrictInfoSCG IE defined in 3GPP TS 36.331 and 38.331. Subsequently, as opposed to sending the first preferred configuration in the UE-assisted information message like event 534A, MN 104A sends 535F an SN modification request message including the IE to SN 106A. Thus, even if SN 106A is a legacy base station that cannot interpret the UE-assisted information message, SN 106A can interpret the SN modification request message and generate 536F a second DU configuration in response to receiving the first preferred configuration via the SN modification request message.

[0217] In some implementations, after generating the second DU configuration, SN 106A sends 538F an RRC reconfiguration message including the second DU configuration to MN104A via an SN modification request confirmation message, and then sends 540F an RRC reconfiguration message to UE 102 via an RRC container message. In response, UE 102 can send 542F an RRC reconfiguration complete message to MN 104A via an RRC container response message, and then send 544F an RRC reconfiguration complete message to SN 106A via an SN reconfiguration complete information. Thus, UE 102 can update multiple configuration parameters previously provided by SN 106A during the DC configuration procedure 560F in the first DU configuration using the second DU configuration, and communicate with SN 106A using the updated configuration parameters. Events 528F, 532F, 533F, 535F, 536F, 538F, 540F, 542F, and 544F are collectively referred to as the legacy UE-assisted information procedure 572F in Figure 5F are collectively referred to as the legacy UE-assisted information procedure 572F.

[0218] At a later time (e.g., after MN 104A or SN 106A detects that the traffic of UE 102 is inactive on the SN terminated radio bearer), MN 104A or SN 06A may initiate a 546F SN release procedure to release SN 106A in UE 102, similar to event 546D. After MN 104A or SN 106A determines to release SN 106A, MN 104A sends a 548F RRC reconfiguration message to UE 102, indicating the release of SN 106B, similar to event 548D. As a result, UE 102 disconnects 550F from SN 106A and retains the first preferred configuration in response to the release of SN 106A, similar to event 550D. Then, in response to the RRC reconfiguration message, UE 102 sends a 552F RRC reconfiguration complete message to MN 104A, similar to event 552D. Thus, after disconnecting from SN106A, UE 102 communicates 554F with MN 104A SC, similar to event 554D.

[0219] At a later time, UE 102 may send a 556F another UE assistance information message including another preferred configuration (i.e., the second preferred configuration) to MN 104A, similar to event 556D, for reasons similar to those described above regarding Figure 5D By sending the second preferred configuration to MN 104A, UE 102 may overwrite the first preferred configuration retained at MN 104A during the legacy UE assistance information procedure 572F, so that UE 102 and MN 104B may communicate using the second preferred configuration. MN 104A may store 558F the second preferred configuration, similar to event 558D. In this way, if MN 104A later determines to perform a DC configuration procedure, MN 104A may adapt to the preferences of UE 102 related to SN 106A, similar to event 560F. In some implementations, MN 104A may release the first preferred configuration at event 558F.

[0220] Later, MN 104A can perform a DC configuration process with an SN (such as SN 106A or SN 106B), similar to DC configuration process 560A. In one implementation, MN 104A can convert a second preferred configuration into an IE (such as a ConfigRestrictInfoSCG IE) that the SN can read, and send an SN addition request message including the IE to the SN during the DC configuration process. Thus, the SN can generate a DU configuration based on the IE to meet the second preferred configuration of UE 102, and send the DU configuration to UE 102 through MN 104A, similar to events 516A and 517A. In another implementation, if MN 104A releases the first preferred configuration, MN 104A can convert the UE capabilities into an IE (such as a ConfigRestrictInfoSCG IE) that the SN can read, and send an SN addition request message including the IE to the SN during the DC configuration process.

[0221] Now refer to Figure 5G , in scenario 500G, base station 104A operates again as the MN of UE 102, and base station 106A operates again as the SN of UE 102. While in Figure 5E , SN 106A determines to perform an SN release process at event 537E, and in Figure 5G , MN 104A determines to perform an SN release process.

[0222] Initially, UE 102 communicates 502G data with MN 104A in the SC through cell 124A by using the MN configuration, similar to event 502E. Later, MN 104A performs a DC configuration process 560G, similar to DC configuration process 590E. As a result, UE 102 communicates control signals and data with MN 104A and SN 106A in the DC by using the first DU configuration received from MN 104A during the DC configuration process 560G.

[0223] After the UE 102 connects to the SN 106A, the MN 104A can initiate a 528G UE-assisted configuration process, similar to event 528E, to enable the UE 102 to send a preferred configuration. After the UE 102 is able to send a preferred configuration, the UE 102 sends a 532G UE-assisted information message including a first preferred configuration to the MN 104, similar to event 532A. The first preferred configuration may include an indication to release the SN 106A or disable 5G. Further, in response to the first preferred configuration, the MN 104A determines to perform a 537G SN release process. Subsequently, the MN 104A sends a 539G SN release request message to the SN 106A, and in turn, the SN 106A sends a 547G SN release request confirmation message to the MN 104A. Further, the MN 104A sends a 548G RRC reconfiguration message to the UE 102, indicating the release of the SN 106A, similar to event 548E. As a result, the UE 102 disconnects from the SN 106A at 550G and, in response to the release of the SN 106A, retains the first preferred configuration, similar to event 550E. Then, in response to the RRC reconfiguration message, the UE 102 sends a 552G RRC reconfiguration complete message to the MN 104A, similar to event 552E. Thus, after disconnecting from the SN 106A, the UE 102 communicates with the MN 104A over SC at 554G, similar to event 554E.

[0224] Later, the UE 102 can send another 556G UE-assisted information message including another preferred configuration (i.e., the second preferred configuration) to the MN 104A, similar to event 556E. For example, the second preferred configuration may include an indication to add the SN 106A that was previously indicated to be released in the first preferred configuration. By sending the second preferred configuration to the MN 104A, the UE 102 can overwrite the first preferred configuration stored in the MN 104A in event 532G, so that the UE 102 and the MN 104B can subsequently communicate using the second preferred configuration. The UE 102 may send the 556G second preferred configuration for reasons similar to those described above with respect to Figure 5E The MN 104A can store the 558G second preferred configuration, similar to event 558E. In this way, if the MN 104A subsequently determines to perform a DC configuration process, the MN 104A can perform the DC configuration process for the UE 102 or adapt the preference related to the SN 106A for the UE 102. In some implementations, the MN 104A may release the first preferred configuration in event 558G.

[0225] Now refer to Figures 6A - 6C , in response to suspending the radio connection to the RAN, the UE 102 retains or releases the preferred configuration.

[0226] First refer toFigure 6A In scenario 600A, base station 104A again operates as the MN of UE 102, and base station 106A again operates as the SN of EU 102. Subsequently, for example, due to data inactivity between UE 102 and SN 106A, the radio connection between UE 102 and SN 106A is suspended. UE 102 and SN 106A retain the first preferred configuration, and subsequently UE 102 provides a second preferred configuration to overwrite the retained first preferred configuration when reconnecting to SN 106A.

[0227] Initially, UE 102 communicates data 602A with MN 104A in the SC via cell 124A using the MN configuration, similar to event 502D. Later, MN 104A performs a DC configuration procedure 660A, similar to DC configuration procedure 560D. As a result, UE 102 communicates control signals and data with MN 104A and SN 106A in the DC using the first DU configuration received from MN 104A during the DC configuration procedure 660A.

[0228] After UE 102 connects to SN 106A, SN 106A initiates a UE-assisted configuration procedure 628A to enable UE 102 to send a preferred configuration. After UE 102 is able to send a preferred configuration, UE 102 performs a UE-assisted information procedure 630A by sending a UE-assisted information message including the first preferred configuration to SN 106A via MN 104A directly or based on different reasons in different scenarios and implementations, similar to event 530A or 531B, as described above. Figure 5A In response to receiving the first preferred configuration, SN 106A then generates 636A a second DU configuration, similar to event 536D.

[0229] In some implementations, after generating the second DU configuration, SN 106A performs an RRC reconfiguration procedure 670A with UE 102, similar to event 570D. Thus, UE 102 can update multiple configuration parameters previously provided by SN 106A during the DC configuration procedure 660A in the first DU configuration using the second DU configuration, and communicate with SN 106A using the updated configuration parameters.

[0230] At a later time (e.g., after SN 106A detects that the traffic of UE 102 is inactive on the SN-terminated radio bearers), SN 106A sends a 682A Activity Notification message to MN 104A, indicating that the traffic of UE 102 is inactive on some or all of the SN-terminated radio bearers. After receiving the Activity Notification message, MN 104A determines that UE 102 should transition to an inactive state. In response to this determination or in response to receiving the Activity Notification message, MN 104A sends a 684A SN Modification Request message for UE 102 to SN 106A. The SN Modification Request message includes an indication that SN 106A should suspend the lower layers of the SN-terminated radio bearers. For example, the SN Modification Request message may indicate that SN 106A should suspend resources of the PHY layer, MAC layer, and / or RLC layer. In response to receiving the SN Modification Request message, SN 106A suspends the lower layers of the SN-terminated radio bearers and sends a 686A SN Modification Application Confirmation message to MN 104A.

[0231] In response to receiving the SN Modification Request Confirmation message, MN 104A performs an RRC suspension procedure 678A, similar to the RRC suspension procedure 378A. As a result, UE 102 suspends the radio connection associated with SN 106A and may transition to an inactive state or an idle state.

[0232] In some implementations, after MN 104A and UE 102 perform the RRC suspension procedure 678A, UE 102 may retain 654A a first preferred configuration (e.g., in response to receiving an RRC suspension message during the RRC suspension procedure 678A). Similarly, in some implementations, SN 106A may retain 653A a first preferred configuration.

[0233] At a later time (e.g., after SN 106A detects that the traffic of UE 102 is active on the SN-terminated radio bearers), in some implementations, SN 106A may send a 688A Activity Notification message to MN 104A, indicating that the traffic of UE 102 is active on some or all of the SN-terminated radio bearers. Subsequently, MN 104A sends a 689A Paging message to UE 102. In response to the Paging message, UE 102 may send a 631A RRC Resume Request message to MN 104A. In other implementations, when determining to initiate data transmission with SN 106A instead of in response to a Paging message, UE 102 may send a 631A RRC Resume Request message to MN 104A.

[0234] In response to receiving an activity notification message from SN 106A or an RRC resume request message from UE 102, MN104A determines that UE 102 should transition back to the connected state. In response to this determination or in response to receiving the activity notification message, MN104A sends a SN modification request message for UE 102 to SN 106A. The SN modification request message includes an indication that SN 106A should resume the lower layer of the SN-terminated radio bearer that was previously suspended in event 684A. For example, the SN modification request message may indicate that SN 106A should resume resources of the PHY layer, MAC layer, and / or RLC layer. In response to receiving the SN modification request message, SN 106A resumes the lower layer of the SN-terminated radio bearer and sends an RRC reconfiguration message 692A to MN 104A via a SN modification application confirmation message, enabling UE 102 to communicate with SN 106A again. Further, MN 104A sends an RRC reconfiguration message 637A to UE 102 via an RRC resume message. As a result, UE 102 resumes the suspended radio connection and transitions to the connected state. UE102 may send an RRC reconfiguration complete message 640A to MN 104A via an RRC resume complete message, and may further send an RRC reconfiguration complete message 694A to SN 106A via a SN reconfiguration complete message.

[0235] Then, UE 102 initiates a random access procedure with SN 106A, for example, by using one or more random access configurations included in the RRC reconfiguration message. After granting access to the channel, SN 106A identifies UE 102 during the random access procedure (e.g., UE 102 successfully resolves contention), and as a result, UE 02 communicates control signals and data with SN 106A.

[0236] Later, UE 102 may directly (not shown) or via MN 104A send another UE assistance information message including another preferred configuration (i.e., the second preferred configuration) to SN 106A in event 657A. By sending the second preferred configuration to SN106A, UE 102 may overwrite the first preferred configuration reserved at SN 106A in event 653A, such that UE 102 and SN106B may subsequently communicate using the second preferred configuration. UE 102 may send the second preferred configuration 656A based on similar reasons described above regarding Figure 3B and Figure 5D In a specific example, UE 102 may send the second preferred configuration to adjust (e.g., increase or decrease) the number of SCell associated with SN 106A, as shown in the first preferred configuration.

[0237] AlthoughFigure 6A Not shown in Figure 6A , SN 106A can continue to perform the second DU reconfiguration process and the second RRC reconfiguration process, which are respectively similar to the second DU reconfiguration process 382B and the second RRC reconfiguration process 384B. Therefore, UE102 can update multiple configuration parameters previously updated according to the first preferred configuration with the second DU configuration generated in the second DU reconfiguration process, and use the updated configuration parameters to communicate with SN 106A.

[0238] Now refer to Figure 6B , in scenario 600B, base station 104A operates as the MN of UE 102 again, and base station 106A operates as the SN of EU 102 again. And in Figure 6A , UE 102 and SN 106A retain the first preferred configuration, and in Figure 6B , UE 102 and SN 106A release the first preferred configuration.

[0239] Initially, UE 102 communicates data 602B with MN 104A in the SC through cell 124A by using the MN configuration, similar to event 602A. Later, MN 104A performs the DC configuration process 660B, similar to the DC configuration process 660A. As a result, UE 102 communicates control signals and data with MN 104A and SN 106A in the DC by using the first DU configuration received from MN 104A during the DC configuration process 660B.

[0240] After UE 102 is connected to SN 106A, MN 104A initiates the 628B UE-assisted configuration process, similar to event 528D, to enable UE 102 to send the preferred configuration. After UE 102 is able to send the preferred configuration, UE 102 performs the UE-assisted information process 630B, similar to event 530A, and sends a UE-assisted information message including the first preferred configuration to SN 106A through MN 104A for different reasons in different scenarios and implementations, as described above regarding Figure 5A . In response to receiving the first preferred configuration, SN 106A then generates 636B the second DU configuration, similar to event 636A.

[0241] In some implementations, after generating the second DU configuration, SN 106A performs the RRC reconfiguration process 670B with UE 102, similar to event 670A. Therefore, UE 102 can update multiple configuration parameters previously provided by SN 106A during the DC configuration process 660B in the first DU configuration with the second DU configuration, and use the updated configuration parameters to communicate with SN 106A.

[0242] At a later time (e.g., after SN 106A detects that the traffic of UE 102 is inactive on the SN-terminated radio bearer), SN 106A sends a 682B activity notification message to MN 104A, similar to event 682A. Then, MN 104A sends a 684B SN modification request message for UE 102 to SN 106A, and in turn, SN 106A sends a 686B SN modification request confirmation message to MN 104A, similar to events 684A and 686A respectively.

[0243] In response to receiving the SN modification request confirmation message, MN 104A performs an RRC suspension procedure 678B, similar to the RRC suspension procedure 678A. As a result, UE 102 suspends the radio connection associated with SN 106A and can transition to an inactive state or an idle state.

[0244] In some implementations, after MN 104A and UE 102 perform the RRC suspension procedure 678B, UE 102 may release the 652B first preferred configuration (e.g., in response to receiving an RRC suspension message during the RRC suspension procedure 678B). Similarly, in some implementations, MN 104A may optionally release the first preferred configuration in event 651B, similar to event 351A. In some implementations, SN 106A may release the first preferred configuration in event 653B, as described below.

[0245] At a later time (e.g., after SN 106A detects that the traffic of UE 102 is active on the SN-terminated radio bearer), SN 106A may send a 688B activity notification message to MN 104A, similar to event 688A. In turn, MN 104A sends a 689B paging message to UE 102, similar to event 689A. In response to the paging message, UE 102 may send a 631B RRC resume request message to MN 104A, similar to event 631A. In other implementations, UE 102 may send a 631B RRC resume request message to MN 104A when determining to initiate data transmission with SN 106A rather than in response to the paging message.

[0246] In response to receiving an activity notification message from SN 106A or an RRC resume request message from UE 102, MN104A determines that UE 102 should transition back to the connected state. In response to this determination or in response to receiving the activity notification message, MN104A sends a SN modification request message for UE 102 to SN 106A, similar to event 690A. In response to receiving the SN modification request message, SN 106A resumes the lower layer of the SN-terminated radio bearer and sends an RRC reconfiguration message 692B to MN 104A via a SN modification application confirmation message to enable UE 102 to communicate with SN 106A again, similar to event 692A. Further, MN 104A sends an RRC reconfiguration message 637B to UE 102 via an RRC resume message, similar to event 637A. As a result, UE102 resumes the suspended radio connection 638B and transitions to the connected state, similar to event 638A. Then, UE 102 can send an RRC reconfiguration complete message 640B to MN 104A via an RRC resume complete message, similar to event 640A, and further can send an RRC reconfiguration complete message 694B to SN 106A via a SN reconfiguration complete message, similar to event 694A.

[0247] Instead of releasing the first preferred configuration in response to an RRC suspension procedure in event 652B, UE 102 receives RRC resume information in response to the initial transmission of an RRC resume message or an RRC resume complete message, or releases the first preferred configuration during the RRC resume procedure, similar to events 352A and 456B.

[0248] In one implementation, after receiving a SN modification request message at event 684B or event 690B, after receiving a SN reconfiguration complete message at event 694B, or at any time between any two of events 682B, 684B, 686B, 688B, 690B, 692B, 694B, SN 106A may release the first preferred configuration 653B after sending an activity notification message 682B.

[0249] Then, UE 102 initiates a random access procedure 696B with SN 106A, similar to event 696A, for example, by using one or more random access configurations included in the RRC reconfiguration message. After granting access to the channel, SN 106A identifies UE 102 in the random access procedure (e.g., UE 102 successfully resolves contention), and thus, UE 02 communicates control signals and data with SN 106A.

[0250] By releasing the first preferred configuration at UE 102, MN 104A, and SN 106A in events 652B, 651B, and 653B respectively, UE 102, MN 104A, and SN 06A do not need to communicate with each other according to the first preferred configuration when resuming a suspended radio connection. For example, UE 102 may have recovered from an overheating situation or a situation where the battery power has increased since the inactive state or the idle state, such that UE 102 can utilize more SCell, MIMO layers, and / or aggregated bandwidth than indicated in the first preferred configuration after transitioning back to the connected state.

[0251] Now referring to Figure 6C , in scenario 600C, base station 104A operates as the MN of UE 102 again, and base station 106A operates as the SN of EU 102 again. And in Figure 6B , SN 106A can receive a UEAssistanceInformation message including the first preferred configuration from MN 104A to generate a second DU configuration in event 636B. In Figure 6C , SN 106A is a legacy base station that cannot interpret the UEAssistanceInformation message. To provide the first preferred configuration to the legacy SN 106A, MN 104A can send the first preferred configuration to SN 104A via an SN modification request message.

[0252] Initially, UE 102 communicates 602C data with MN 104A in the SC via cell 124A by using the MN configuration, similar to event 602B. Later, MN 104A performs a DC configuration procedure 660C, similar to the DC configuration procedure 660B. As a result, UE 102 communicates control signals and data with MN 104A and SN 106A in the DC by using the first DU configuration received from MN 104A during the DC configuration procedure 660C.

[0253] After the UE 102 is connected to the SN 106A, the MN 104A, the SN 106A, and the UE 102 jointly perform a legacy UE-assisted information procedure 672C, similar to the legacy UE-assisted information procedure 572F. In the legacy UE-assisted information procedure 672C, the MN 104A may convert a first preferred configuration included in a UE-assisted information message into an IE (e.g., a ConfigRestrictInfoSCG IE) that the SN 106A can read. Thus, even if the SN 106A is a legacy base station that cannot interpret the UE-assisted information message, the SN 106A can interpret the IE and generate a second DU configuration based on the first preferred configuration. Accordingly, the UE 102 may update a plurality of configuration parameters previously provided by the SN 106A during the DC configuration procedure 660C in the first DU configuration with the second DU configuration, and communicate with the SN 106A using the updated configuration parameters.

[0254] At a later time (e.g., after the SN 106A detects that the traffic of the UE 102 is inactive on the SN-terminated radio bearer), the SN 106A sends a 682C activity notification message to the MN 104A, similar to event 682B. Then, the MN 104A sends a 684C SN modification request message for the UE 102 to the SN 106A, and in turn, the SN 106A sends a 686C SN modification request confirmation message to the MN 104A, similar to events 684B and 686B, respectively.

[0255] In response to receiving the SN modification request confirmation message, the MN 104A performs an RRC suspension procedure 678C, similar to the RRC suspension procedure 678B. As a result, the UE 102 suspends the radio connection associated with the SN 106A and may transition to an inactive state or an idle state.

[0256] In some implementations, after the MN 104A performs the RRC suspension procedure 678C for the UE 102, the UE 102 may release 652C the first preferred configuration (e.g., in response to receiving an RRC suspension message during the RRC suspension procedure 678C). Similarly, in some implementations, the MN 104A may release 651C the first preferred configuration.

[0257] At a later time (e.g., after SN 106A detects that the traffic of UE 102 is active on the SN-terminated radio bearer), SN 106A may send a 688C activity notification message to MN 104A, similar to event 688B. Subsequently, MN 104A sends a 689C paging message to UE 102, similar to event 689B. In response to the paging message, UE 102 may send a 631C RRC resume request message to MN 104A, similar to event 631B. In other implementations, UE 102 may send a 631C RRC resume request message to MN 104A when determining to initiate data transmission with SN 106A rather than in response to a paging message.

[0258] In response to receiving an activity notification message from SN 106A or an RRC resume request message from UE 102, MN 104A determines that UE 102 should transition back to the connected state. In response to this determination or in response to receiving an activity notification message, MN 104A sends a 690C SN modification request message for UE 102 to SN 106A. The SN modification request message may include IEs generated by MN 104A during the legacy UE assistance information procedure 672C or otherwise include modified IEs to adjust (e.g., increase or decrease) the number of SCell associated with SN 106A, as shown in the first preferred configuration. In response to receiving the SN modification request message, SN 106A resumes the lower layer of the SN-terminated radio bearer and sends a 692C RRC reconfiguration message to MN 104A via an SN modification application confirmation message to enable UE 102 to communicate with SN 106A again, similar to event 692B. Subsequently, MN 104A sends a 637C RRC reconfiguration message to UE 102 via an RRC resume message, similar to event 637B. As a result, UE 102 resumes the 638C suspended radio connection and transitions to the connected state, similar to event 638B. UE 102 may send a 640C RRC reconfiguration complete message to MN 104A via an RRC resume complete message, similar to event 640B, and subsequently MN 104B may send a 694C RRC reconfiguration complete message to SN 106A via an SN reconfiguration complete message, similar to event 694B.

[0259] Then, UE 102 initiates a random access procedure with SN 106A, similar to event 696B. After granting access to the channel, SN 106A identifies UE 102 in the random access procedure (e.g., UE 102 successfully resolves contention), and thus, UE 02 communicates control signals and data with SN 106A.

[0260] By releasing the first preferred configuration at UE 102 and MN 104A in events 652C and 651C respectively, UE 102, MN 104A, and SN 106A do not need to communicate with each other according to the first preferred configuration when resuming a suspended radio connection. For example, UE 102 may have recovered from an overheating situation or a situation where the battery power has increased since the inactive state or the idle state, such that UE 102 can utilize more SCell, MIMO layers, and / or aggregated bandwidth than indicated in the first preferred configuration after transitioning back to the connected state.

[0261] Now referring to Figure 7 , in the PSCell change scenario 700, base station 104A operates again as the MN of UE 102, and base station 106A operates again as the SN of UE 102. In the PSCell change scenario 700, SN 106A (i.e., S-SN) can forward the first preferred configuration to the T-SN (e.g., T-SN 106B) through MN 104A, so that when UE 102 performs the PSCell change procedure from the PSCell of S-SN 106A to the target PSCell of T-SN 106, SN 106B can know the first preferred configuration.

[0262] Initially, UE 102 communicates data 702 with MN 104A in the SC through cell 124A by using the MN configuration, similar to event 502A. Later, MN 104A performs the DC configuration procedure 760, similar to the DC configuration procedure 560A. As a result, UE 102 communicates control signals and data with MN 104A and S-SN 106A in the DC by using the first DU configuration received from MN 104A during the DC configuration procedure 760.

[0263] After UE 102 is connected to S-SN 106A, MN 104A or S-SN 106A initiates 728 the UE-assisted configuration procedure to enable UE 102 to send the preferred configuration. After UE 102 is able to send the preferred configuration, UE 102 performs the UE-assisted information procedure 730, similar to event 530A or 531B, to send a UE-assisted information message including the first preferred configuration to S-SN 106A through MN 104A directly or for different reasons in different scenarios and implementations, as described above Figure 5A stated. Then, in response to receiving the first preferred configuration, S-SN 106A generates 736 the second DU configuration, similar to event 536A.

[0264] In some implementations, after generating the second DU configuration, S-SN 106A and UE 102 perform an RRC reconfiguration procedure 770, similar to event 570A or 571B. Accordingly, UE 102 can update the plurality of configuration parameters previously provided by S-SN 106A during the DC configuration procedure 760 in the first DU configuration with the second DU configuration, and communicate with S-SN 06A using the updated configuration parameters.

[0265] Later, MN 104A determines to initiate a PSCell change involving an SN change of T-SN 106B and UE 102 (i.e., an MN-initiated SN addition or change procedure) to communicate via T-PSCell 126B, e.g., blindly or in response to detecting an appropriate event. For example, the determination can be made in response to MN 104A receiving one or more measurement results from UE 102 that are higher (or lower) than one or more predetermined thresholds, or calculating a filtered result (from the measurement results) that is higher (or less) than a predetermined threshold. In another example, the appropriate event can be UE 102 moving towards T-SN 106B. In yet another example, the appropriate event can be one or more measurement results generated or obtained by MN 104A based on measurements of signals received from UE 102 that are higher (or lower) than one or more predetermined thresholds.

[0266] In response to determining to initiate a PSCell change, MN 104A sends a 740 SN addition request message to T-SN 106B. In some implementations, the SN addition request message includes the UE capabilities and the first preferred configuration received in events 702 and 738. In some implementations, if T-SN 106B is a legacy base station that cannot interpret the first preferred configuration, the SN addition request message can include an IE (e.g., ConfigRestrictInfoSCG IE) corresponding to the transformation of the first preferred configuration. In some implementations, if MN104A does not receive the first preferred configuration in event 730 (e.g., similar to event 531B), then MN 104A can receive the first preferred configuration in event 738 in the SN message from S-SN 106A. In some implementations, the SN message can be an SN change request message, an SN modification request message, an SN modification request confirmation message. In other implementations, SN 106A can include the first preferred configuration or a UE assistance information message including the first preferred configuration in the CG-Config IE in the SN message.

[0267] In response, T-SN 106B generates a third DU configuration and sends the third DU configuration in the RRC reconfiguration message to MN 104A via the SN addition request confirmation message. T-SN 106B generates the third DU configuration in response to the first preferred configuration in a manner not exceeding the capabilities of UE 102, e.g., by considering the UE capabilities included in the SN addition request message.

[0268] In response to receiving the 742 SN addition request confirmation message from T-SN 106B, MN 104A includes the RRC reconfiguration message in the RRC container message and sends the 744 RRC container message to UE 102. In some implementations, the RRC container message may include one or more random access configurations required for UE 102 to connect to T-SN 106B, and in some implementations, may also include other fields, such as a mobility field (e.g., the mobilityControlInfoSCG field or the reconfigurationWithSync field), which may include part or all of the random access configuration.

[0269] In response to receiving the 744 RRC container message, UE 102 sends an RRC container response message including an RRC reconfiguration complete message to MN 104A. In some implementations, MN 104A may, in response to the RRC container response message, send an SN message (e.g., an SN reconfiguration complete message or an SN confirmation message) including the RRC reconfiguration complete message to T-SN 106B.

[0270] In response to receiving the 744 RRC container message, UE 102 attempts to change the PSCell to T-SN 106B via T-PSCell 126B according to the configuration included in the RRC reconfiguration message. When attempting to perform the PSCell change, UE 102 initiates a 750 random access procedure with T-SN 106B via T-PSCell 126B, e.g., by using one or more random access configurations in the RRC reconfiguration message. After T-SN 106B identifies UE 102 during the random access procedure (e.g., UE 102 successfully resolves contention), UE 102 communicates 752 with MN 104A and T-SN 06B in DC via T-PSCell 126B using the configuration in the RRC reconfiguration message included in the RRC container message. Later, UE 102 may provide a second preferred configuration to override the first preferred configuration to T-SN 106B, e.g., in a similar manner as described for event 530A. UE 102 may send the second preferred configuration for different reasons in various scenarios and implementations as described above.

[0271] In some scenarios and implementations, S-SN 106A receives a first UE preferred configuration and does not provide the first UE preferred configuration to MN 104A, such that MN 104A cannot provide the first UE-preferred configuration to T-SN 106B. After the UE 102 successfully executes the 752 random access procedure, the UE 102 may provide a second preferred configuration to T-SN 106B, for example, in a manner similar to that described for event 530A or 531B. Due to the same or different reasons as when the UE 102 sent the first preferred configuration, the UE 102 may send the second preferred configuration. The second preferred configuration may be the same as or different from the first preferred configuration.

[0272] In some scenarios and implementations, the UE 102 may receive an RRC reconfiguration message (similar to event 531B) in event 744 either simultaneously or immediately after sending a UE assistance information message to the S-SN 106A via SRB3. Before successfully sending the UE assistance information message to the S-SN 106A, the UE 102 may disconnect from the S-SN 106A and perform a 750 random access procedure on cell 126B. In other scenarios and implementations, after the MN 104A sends a 740 SN addition request message, the UE 102 sends a UE assistance information message to the MN 104A (similar to event 532A) or to the S-SN 106A (similar to event 531B). In these scenarios and implementations, the UE 102 cannot ensure that the T-SN 106B receives the UE assistance information message from the S-SN 106A. After the UE 102 successfully executes the 752 random access procedure, the UE 102 may provide a second preferred configuration to the T-SN 106B, for example, in a manner similar to that described for event 530A or 531B. The second preferred configuration may be the same as or different from the first preferred configuration. If the MN 104A receives a UE assistance information message or a first UE preferred configuration after sending the 740 SN addition request message, the MN 104A may send another SN message (i.e., a second SN message) including the UE assistance information message or the first UE preferred configuration to the T-MN 106B. More specifically, before sending the 746 RRC container message, the UE 102 sends a UE assistance information message or a first UE preferred configuration to the MN 104A.

[0273] In some implementations, if the RRC reconfiguration message enables the UE 102 to send a preferred configuration or enables the UE 102 to send a UE assistance information message, the UE 102 sends a second preferred configuration (similar to event 530A or 531B) to the T-SN 106B. Otherwise, the UE 102 prohibits the transmission of the preferred configuration or the UE assistance information message. If the UE 102 sends a UE assistance information message (similar to event 531B) to the S-SN 106A via SRB3 immediately when receiving the RRC reconfiguration message or immediately before receiving the RRC reconfiguration message, the UE 102 may re-send the UE assistance information message (i.e., the first preferred configuration) to the T-SN 106B. If the UE 102 sends a UE assistance information message to the S-SN 106A via the MN 104 immediately when receiving the RRC reconfiguration message or immediately before receiving the RRC reconfiguration message, the UE 102 does not re-send the UE assistance information message to the T-SN 106B. "Immediately" used in this paragraph may be a short duration, such as X seconds (e.g., X = 1 or 0 < X < 10, such as X = 1, 1.1, 1.2…, 2… or 9).

[0274] In one implementation, if the UE 102 receives an RRC reconfiguration message including a secondary cell group configuration (e.g., secondaryCellGroup) from the S-SN 106A on SRB3 or via the MN 104A, and the UE 102 has sent a UE assistance information message during the last X seconds (e.g., X = 1, 0 < X < 10, such as X = 1, 1.1, 1.2…, 2… or 9), and is still configured to send a preferred configuration via the RRC reconfiguration message, the UE 102 may re-send the UE assistance information message to the T-SN 106B (similar to event 530A or 531B) after completing the random access procedure. Optionally, instead of re-sending, the UE 102 may send another UE assistance information message to the T-SN 106B including content similar to the previously sent UE assistance information message. Otherwise, after completing the random access procedure, the UE 102 cannot re-send the UE assistance information message to the MN 104A or the T-SN 106B, or send another UE assistance information message to the MN 104A or the T-SN 106B including content similar to the previously sent UE assistance information message.

[0275] In another implementation, when the UE 102 receives an RRC reconfiguration message including a secondary cell group configuration (e.g., secondaryCellGroup) from the S-SN 106A on SRB3 or via the MN 104A, and if the UE 102 has sent a UE assistance information message and has not received an acknowledgement message (e.g., RLC control PDU, PDCP control PDU, or HARQ acknowledgement) for the UE assistance information message from the MN 104A or the S-SN 106A, after completing the random access procedure, the UE 102 may re-transmit the UE assistance information message to the T-SN 106B (similar to event 530A or 531B). Optionally, instead of re-transmitting, the UE 102 may send another UE assistance information message including content similar to the previously sent UE assistance information message to the T-SN 106B (similar to event 530A or 531B). Otherwise, after completing the random access procedure, the UE 102 does not re-transmit the UE assistance information message to the MN 104A or the T-SN 106B, or sends another UE assistance information message including content similar to the previously sent UE assistance information message to the MN 104A or the T-SN 106B.

[0276] However, in Figure 7 for the UE 102, the PSCell change scenario 700 occurs between two base stations (e.g., base stations 104A, 106A). For the UE 02, the above description can be applied to the PSCell change scenario within a single base station (e.g., base station 106A). The description for the UE 102 and the T-SN 106B can be applied to the UE 102 and the S-SN 106A. For example, the S-SN 106A may send an RRC reconfiguration message to the UE 102 via SRB3 to configure the UE 102 to perform a PSCell change from the PSCell 126A to a new PSCell (i.e., the second cell operated by the S-SN 06A, not shown in FIG. 1). In response, the UE 102 may send an RRC reconfiguration complete message to the S-SN 106A via SRB3. In another example, the S-SN 106A may send an RRC reconfiguration message to the UE 102 via the MN104A to configure the UE 102 to perform a PSCell change from the PSCell 126A to another cell (not shown in FIG. 1). In response, the UE 102 may send an RRC reconfiguration complete message to the S-SN 106A via the MN 104A.

[0277] In some scenarios and implementations, the UE 102 may receive an RRC reconfiguration message (similar to event 531B) while or immediately after sending a UE assistance information message to the S-SN 106A via SRB3. Before successfully sending the UE assistance information message to the S-SN 106A, the UE 102 may disconnect from the PSCell 126A and perform a random access procedure on a new PSCell. In such a scenario and implementation, the UE 102 cannot ensure that the S-SN 106A receives the UE assistance information message from the PSCell 126A. After the UE 102 successfully performs a random access procedure on the new PSCell, the UE 102 may provide a second preferred configuration to the S-SN 106A, for example, in a manner similar to that described for event 531B. The second preferred configuration may be the same as or different from the first preferred configuration.

[0278] In some implementations, if the RRC reconfiguration message enables the UE 102 to send a preferred configuration or enables the UE 102 to send a UE assistance information message, the UE 102 sends the second preferred configuration to the S-SN 106A via the new PSCell (similar to event 530A or 531B). Otherwise, the UE 102 prohibits the transmission of the preferred configuration or the UE assistance information message. If the UE 102 sends the UE assistance information message to the S-SN 106A via the PSCell 126A (similar to event 531B) via SRB3 when or before receiving the RRC reconfiguration message, the UE 102 may re-send the UE assistance information message (i.e., the first preferred configuration) to the S-SN 106A via the new PSCell. If the UE 102 sends the UE assistance information message to the S-SN 106A via the MN 104 when or before receiving the RRC reconfiguration message, the UE 102 does not re-send the UE assistance information message to the S-SN 106A. As described above, "immediately" used in this paragraph may be a short duration, such as X seconds (e.g., X = 1 or 0 < X < 10, e.g., X = 1, 1.1, 1.2…, 2, … or 9).

[0279] In one implementation, if UE 102 receives an RRC reconfiguration message including a secondary cell group configuration (e.g., secondaryCellGroup) from S-SN 106A on SRB3 or via MN 104A, and UE 102 has sent a UE assistance information message within the last X seconds (e.g., X = 1 or 0 < X < 10, e.g., X = 1, 1.1, 1.2…, 2, … or 9), and is still configured to send the preferred configuration via the RRC reconfiguration message, then after completing the random access procedure on the new PSCell, UE 102 may retransmit the UE assistance information message to S-SN 106A via SRB3 on the new PSCell (similar to 531B). Optionally, instead of retransmitting, UE 102 may send another UE assistance information message including content similar to the previously sent UE assistance information message to S-SN 106A on the new PSCell. Otherwise, after completing the random access procedure on the new PSCell, UE 102 does not retransmit the UE assistance information message to MN 104A or S-SN 106A, nor does it send another UE assistance information message including content similar to the previously sent UE assistance information message to MN 104A or -SN 106A.

[0280] In another implementation, when UE 102 receives an RRC reconfiguration message including a secondary cell group configuration (e.g., secondaryCellGroup) from S-SN 106A on SRB3 or via MN 104A, if UE 102 has sent a UE assistance information message on SRB3 and has not received an acknowledgement message (e.g., RLC control PDU, PDCP control PDU or HARQ acknowledgement) of the UE assistance information message from S-SN 106A, then after completing the random access procedure on the new PSCell, UE 102 may retransmit the UE assistance information message to S-SN 106A via SRB3 on the new PSCell (similar to event 531B). Optionally, instead of retransmitting, UE 102 may send another UE assistance information message including content similar to the previously sent UE assistance information message to S-SN 106A. Otherwise, after completing the random access procedure on the new PSCell, UE 102 does not retransmit the UE assistance information message to MN 104A or S-SN 106A on the new PSCell, nor does it send another UE assistance information message including content similar to the previously sent UE assistance information message to MN 104A or S-SN106A on the new PSCell.

[0281] After completing the random access procedure with S-SN 106A on the new PSCell, UE 102 may retransmit the UE assistance information message to S-SN 106 via the new PSCell (similar to event 530A or 531B). Optionally, instead of retransmitting, UE 102 may send another UE assistance information message to S-SN 106B that includes similar content to the previously transmitted UE assistance information message.

[0282] Figure 8A It is a flowchart depicting an example method 800A for releasing a preferred configuration implemented in a UE (such as UE 102).

[0283] At block 802A, the UE transmits the preferred configuration (e.g., in any one of events 372A, 372C, 472B). In various implementations, the UE may transmit the preferred configuration directly or via MN 104A to a base station (e.g., base station 104A, S-BS 104B, or SN 106A).

[0284] At block 804A, the UE receives an RRC suspension message and suspends the radio connection in response to the RRC suspension information (e.g., in any one of events 378A, 378C, 478B).

[0285] At block 806A, in some implementations, the UE releases the preferred configuration in response to the RRC suspension message (e.g., in any one of 352A, 456B). In other implementations, before receiving the RRC suspension message at block 804A, the UE releases the preferred configuration (e.g., in event 356C). For example, during the UE-assisted release procedure, the base station may send an RRC message to the UE to indicate that the UE releases the first preferred configuration.

[0286] Figure 8B It is a flowchart depicting an example method 800B for releasing a preferred configuration as an alternative to example method 800A implemented in a UE (such as UE 102).

[0287] At block 802B, similar to block 802A, the UE transmits the preferred configuration (e.g., in any one of events 372A, 372C, 472B).

[0288] At block 804B, similar to block 804A, the UE receives an RRC suspension message and suspends the radio connection in response to the RRC suspension information (in any one of events 378A, 378C, 478B).

[0289] At block 806B, the UE performs an RRC resume procedure to resume a suspended radio connection (e.g., in any one of 380A, 380C, 480B). For example, the UE may perform the RRC resume procedure in response to determining to initiate data transmission with the base station, or in response to a paging message received from the base station.

[0290] Whereas in block 806A, the UE releases the preferred configuration in response to an RRC suspend message, and in block 808B, the UE releases the preferred configuration in response to (or during) the RRC resume procedure.

[0291] Figure 9 is a flowchart depicting an example method 900 implemented in a UE (e.g., UE 102) for maintaining a preferred configuration. Thus, as opposed to releasing the preferred configuration related above Figure 8A and Figure 8B the UE and the base station may alternately retain the preferred configuration, but may overwrite the preferred configuration with another preferred configuration if necessary.

[0292] At block 902, similar to block 802A, the UE transmits the preferred configuration (e.g., in any one of event 372B, 472A). In various implementations, the UE may directly or via the MN 104A transmit the preferred configuration to the base station (e.g., base station 104A, S - BS104B or SN 106A).

[0293] At block 904, similar to block 804A, the UE receives an RRC suspend message and suspends the radio connection in response to the RRC suspend information (e.g., in any one of event 378B, 478A).

[0294] However, in block 806A, the UE releases the preferred configuration in response to the RRC suspend message, while in block 906 the UE retains the preferred configuration in response to the RRC suspend message (e.g., in any one of event 354B, 454A).

[0295] At block 908, similar to block 806B, the UE performs an RRC resume procedure to resume the suspended radio connection (e.g., in any one of 380B, 480A).

[0296] At block 910, the UE sends another (i.e., second) preferred configuration to the base station to update the previously transmitted preferred configuration (e.g., in any one of 344B, 444A). By sending the second preferred configuration to the base station, the UE may overwrite the previously transmitted preferred configuration retained at the base station, such that when resuming the connection with the base station, the UE and the base station may communicate using the second preferred configuration, for example.

[0297] Figure 10AIt is a flowchart depicting an example method 1000A implemented in a UE (e.g., UE 102) for disconnecting from and releasing a preferred configuration with an SN (e.g., SN 106A).

[0298] At block 1002A, the UE sends the preferred configuration to the SN (e.g., in any one of events 530A, 531B, 530C). In various implementations, the UE can send the preferred configuration directly to the SN or via an MN (e.g., MN 104A).

[0299] At block 1004A, the UE receives an RRC message (e.g., an RRC reconfiguration message) from the MN indicating the release of the SN (e.g., in any one of events 548A, 548B, 548C).

[0300] At block 1006A, the UE disconnects from the SN and releases the preferred configuration in response to the RRC message (e.g., in any one of events 550A, 550B, 550C).

[0301] Figure 10B It is a flowchart depicting an example method 1000B, which is an alternative to example method 1000A, implemented in a UE (e.g., UE 102) for disconnecting from and releasing a preferred configuration with an SN (e.g., SN 106A).

[0302] At block 1002B, similar to block 1002A, the UE sends the preferred configuration to the SN (e.g., in any one of events 530A, 531B, 530C).

[0303] At block 1004B, similar to block 1004A, the UE receives an RRC message (e.g., an RRC reconfiguration message) indicating the release of the SN (e.g., in any one of events 548A, 548B, 548C).

[0304] However, in block 1006A, the UE disconnects from the SN and releases the preferred configuration in response to the RRC message. In block 1006B, the UE disconnects from the SN but has not yet released the preferred configuration. Instead, at block 1008B, the UE receives another (i.e., a second) RRC message (e.g., an RRC resume message) indicating the addition of an SN (e.g., an SN that is the same as or different from SN 106A), and subsequently at block 1010B, releases the preferred configuration in response to the second RRC message.

[0305] Figure 11 It is a flowchart depicting an example method 1100 implemented in a UE (e.g., UE 102) for disconnecting from an SN (e.g., SN 106A) and retaining the preferred configuration. Thus, as opposed to releasing the above regarding Figure 10A and 10BRelative to the preferred configuration, the UE and the base station can alternatively retain the preferred configuration, but if necessary, the preferred configuration can be overwritten with another preferred configuration.

[0306] In block 1102, similar to block 1002A, the UE sends the preferred configuration to the SN (e.g., in event 630A).

[0307] In block 1104, similar to block 1004A, the UE receives a first RRC message (e.g., an RRC reconfiguration message) from the MN indicating the release of the SN (e.g., in event 678A).

[0308] While in block 1006A, in response to the first RRC message, the UE disconnects from the SN and releases the preferred configuration, in block 1106, in response to the first RRC message, the UE disconnects from the SN and retains the preferred configuration (e.g., in event 654A).

[0309] In block 1108, the UE receives a second RRC message (e.g., an RRC resume message) indicating the addition of the SN (e.g., an SN that is the same as or different from SN 106A) (e.g., in event 637A).

[0310] In block 1110, in response to the second RRC message (e.g., in event 656A), the UE sends another (i.e., a second) preferred configuration to the SN to update the previously sent preferred configuration. By sending the second preferred configuration to the SN, the UE can overwrite the previously sent preferred configuration retained on the SN, so that when reconnecting to the SN, the UE and the SN can communicate using the second preferred configuration, for example.

[0311] Figure 12A Is a flowchart of an example method 1200A implemented in the MN (e.g., MN 104A) for determining whether to perform a UE-assisted configuration process to enable a UE (e.g., UE 102) to send a preferred configuration to an SN (e.g., SN 106A).

[0312] In block 1202A, the MN receives the UE capabilities of the UE. In various implementations, the MN can receive the UE capabilities from the UE, the CN (e.g., CN 110), or another base station (e.g., base station 104B).

[0313] In block 1204A, the MN determines whether the UE capabilities indicate that the UE supports sending the preferred configuration. If in block 1204A, the MN determines that the UE capabilities indicate that the UE cannot send the preferred configuration, then in block 1210A, the MN does not perform the UE-assisted configuration process.

[0314] If at block 1204A, the MN determines that the UE capabilities indicate that the UE is capable of sending a preferred configuration, then at block 1206A, the MN determines whether the SN is capable of handling the preferred configuration. For example, the MN may be preconfigured to know the capabilities of the SN. In another example, a network node (e.g., an operations and maintenance (O&M) node) may notify the MN of the capabilities of the SN.

[0315] If at block 1206A, the MN determines that the SN is not capable of handling the preferred configuration, then at block 1210A, the MN does not perform the UE-assisted configuration procedure. If at block 1206A, the MN determines that the SN is capable of handling the preferred configuration, then at block 1208A, the MN performs the UE-assisted configuration procedure (e.g., in any of events 528A, 528B, 528C, 528D, 528E, 528F, 528G, 628A, 628B, 672C, 728). During the UE-assisted configuration procedure, the MN may send an RRC message to the UE, enabling the UE to send the preferred configuration to the SN.

[0316] Figure 12B is a flowchart depicting an example method 1200B implemented in the MN (e.g., MN 104A) for determining whether to send a preferred configuration to the SN (e.g., SN 106A).

[0317] At block 1202B, the MN receives the UE preferred configuration (e.g., in any of events 530A, 530C, 530D, 530E, 630A, 630B, 672C, 730). For example, the MN may receive the UE preferred configuration from the UE via a UE-assisted information message.

[0318] At block 1204B, similar to block 1206A, the MN determines whether the SN is capable of handling the UE preferred configuration.

[0319] If at block 1204B, the MN determines that the SN is unable to handle the preferred configuration, then at block 1208B, the MN does not send the preferred configuration to the SN. If at block 1204B, the MN determines that the SN is capable of handling the preferred configuration, then at block 1206B, the MN sends the preferred configuration to the SN (e.g., in any of events 530A, 530C, 530D, 530E, 630A, 630B, 730).

[0320] Figure 12C is a flowchart depicting an example method 1200C implemented in the SN (e.g., SN 106A) for determining whether to act on a UE preferred configuration received from the MN (e.g., MN 104A).

[0321] At block 1202C, the SN receives a UE preferred configuration from the MN (e.g., in any of events 530A, 530D, 630A, 630B, 730).

[0322] At block 1204C, the SN determines whether it can process the UE preferred configuration. For example, if the SN cannot understand the UE preferred configuration, or understands the UE preferred configuration but cannot generate a DU configuration in response to receiving the UE preferred configuration, the SN determines that it cannot process the UE preferred configuration.

[0323] If at block 1204C, the SN determines that it cannot process the UE preferred configuration, then at block 1208C, the SN ignores the UE preferred configuration. In some implementations, the SN does not send an error message to the MN indicating that the SN cannot process the UE preferred configuration. For example, the SN may send an SN add request confirmation message to the MN instead of an SN add rejection message.

[0324] If at block 1204C, the SN determines that it can process the UE preferred configuration, then at block 1206C, the SN generates a DU configuration based on the UE preferred configuration (e.g., in any of events 536A, 536D, 636A, 636B, 736).

[0325] Figure 13 is a flowchart depicting an example method 1300 implemented in a distributed SN (e.g., SN 106A) for processing a UE preferred configuration received from an MN (e.g., MN 104A) within the distributed SN.

[0326] At block 1302, the CU of the distributed SN receives a UE preferred configuration from the MN (e.g., in any of events 530A, 530D, 630A, 630B, 730).

[0327] At block 1304, the CU sends the UE preferred configuration to the DU (e.g., in any of 536A, 536D, 636A, 636B, 736).

[0328] At block 1306, in response to the UE preferred configuration, the CU receives a DU configuration from the DU (e.g., in any of 536A, 536D, 636A, 636B, 736).

[0329] Figure 14A is a flowchart depicting an example method 1400A implemented in an MN (e.g., MN 104A) for analyzing a UE preferred configuration.

[0330] At block 1402A, the MN receives a UE preferred configuration (e.g., in event 532F). For example, the MN may receive the UE preferred configuration from the UE (e.g., UE 102) via a UE assistance information message.

[0331] At block 1404A, the MN determines whether the reducedCCsDL IE in the UE preferred configuration is set to 0. The reducedCCsDL IE indicates the maximum number of SCell(s) that the UE desires to be configured temporarily in the downlink communication with the SN (e.g., SN 106A). Thus, if the reducedCCsDL IE is set to 0 in the UE preferred configuration, the UE indicates that it does not prefer to connect to the SN.

[0332] If at block 1404A, the MN determines that the reducedCCsDL IE is set to 0, then at block 1406A, the MN sends an SN release request message to the SN to release the SN. If at block 1404A, the MN determines that the reducedCCsDL IE is not set to 0, then at block 1408A, the MN generates a ConfigRestrictInfoSCG IE from the UE preferred configuration and sends the ConfigRestrictInfoSCG IE (e.g., in an SN modification request message) to the SN (e.g., for events 533F, 535F). Thus, even if the SN is a legacy base station that cannot interpret a UE assistance information message including the UE preferred configuration, the SN can interpret the SN modification request message to read the UE preferred configuration.

[0333] Figure 14B is a flowchart depicting an example method 1400B implemented in the SN (e.g., SN 106A) for analyzing the UE preferred configuration.

[0334] At block 1402B, the SN receives the UE preferred configuration from the MN (e.g., in any one of events 530A, 530C, 530D, 530E, 535F, 630A, 630B, 730).

[0335] At block 1404B, the SN determines whether the reducedCCsDL IE in the UE preferred configuration is set to 0.

[0336] If, at block 1404B, the SN determines that the reducedCCsDL IE is set to 0, then at block 1406B, the SN sends a SN release request message to the MN, requesting the MN to release the SN (e.g., in events 546C, 546E). If, at block 1404B, the SN determines that the reducedCCsDL IE is not set to 0, then at block 1408B, the SN generates a DU configuration according to a preferred configuration (e.g., in any one of events 536A, 536D, 536F, 636A, 636B, 736), and sends the DU configuration to the UE directly or via the MN (e.g., in any one of events 570A, 570D, 538F, 670A, 670B, 770).

[0337] Next, Figure 15 An example method 1500 for managing a preferred configuration that can be implemented in a suitable UE (such as UE 102) is shown. At block 1502, the UE sends a preferred configuration to a base station in the RAN, as discussed, for example, with reference to blocks 802A, 802B, or 902. At block 1504, the UE transitions to a state where the radio connection between the UE and the RAN is suspended, such as RRC_INACTIVE (e.g., block 806A, 806B, or 906). At block 1506, the UE releases the preferred configuration before communicating data via the radio connection (e.g., block 806A, 810B, 910).

[0338] Next, Figure 16 An example method 1600 for managing a preferred configuration that can be implemented in a suitable UE (e.g., UE 102) is shown.

[0339] At block 1602, the UE performs DC communication with the MN and the SN (e.g., in event 560A).

[0340] Then, at block 1604, the UE sends a UE assistance information message to the SN in the RAN in DC (e.g., in any one of 530A, 531B).

[0341] At block 1606, the UE receives an RRC message including mobility information of the SCG when sending or after sending the UE assistance information message (e.g., in event 744).

[0342] At block 1608, in response to the RRC message (i.e., according to the mobility information), the UE performs a mobility operation (e.g., in event 750).

[0343] At block 1610, the UE determines whether the RRC message enables the transmission of the UE assistance information message. If at block 1610, the UE determines that the RRC message disables the transmission of the UE assistance information message, then at block 1612, in response to the RRC message, the transmission of the UE assistance information message is disabled. If at block 1610, the UE determines that the RRC message enables the transmission of the UE assistance information message, then at block 1614, the UE determines that the UE assistance information message is being sent to the SN via the MN (i.e., via SRB1) or SRB3. If the UE assistance information is being sent to the SN via SRB3, then at block 1616, the UE re - sends the UE assistance information message to the SN. If the UE assistance information message is being sent to the SN via the MN (i.e., via SRB1), then at block 1618, the UE prohibits re - sending the UE assistance information message to the SN.

[0344] In some implementations, the mobility information of the SCG can be the secondary cell group configuration (e.g., secondaryCellGroup) in the RRC message, or the ReconfiguraitonWithSync IE included in the secondary cell group configuration of the RRC message. The mobility operation can be a PSCell change or an SN change.

[0345] The following description may apply to the above description.

[0346] The user equipment (e.g., UE 102) that can implement the technology of the present invention can be any suitable device capable of wireless communication, such as a smart phone, a tablet computer, a laptop computer, a mobile game console, a point - of - sale (POS) terminal, a health monitoring device, a drone, a camera, a media streaming dongle or other personal media devices, wearable devices such as smart watches, wireless hotspots, femtocells or broadband routers. In addition, in some cases, the user equipment can be embedded in an electronic system, such as the head unit of a vehicle or an advanced driver assistance system (ADAS). In addition, the user equipment can operate as an Internet of Things (IoT) device or a mobile Internet device (MID). Depending on the type, the user equipment can include one or more general - purpose processors, computer - readable memory, a user interface, one or more network interfaces, multiple sensors, etc.

[0347] The present invention describes certain implementations, 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 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 an 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., included in 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 dedicated and permanently configured circuitry or temporarily configured circuitry (e.g., configured by software) may be influenced by cost and time factors.

[0348] When implemented in software, these techniques can be provided as part of an operating system, a library used by multiple application processes, a specific software application process, etc. The software can be executed by one or more general-purpose processors or one or more dedicated processors.

[0349] Example 1. A method for managing a preferred configuration indicating a maximum allocation preferred by a UE for at least one resource, the method comprising: sending the preferred configuration to a radio access network (RAN) by processing hardware; transitioning by the processing hardware to a state in which a radio connection between the UE and the RAN is suspended; and releasing the preferred configuration by the processing hardware before communicating data via the radio connection.

[0350] Example 2. The method according to Example 1, wherein the release is in response to receiving an indication that the radio connection is suspended from the RAN.

[0351] Example 3. The method according to Example 1, further comprising retaining the preferred configuration in response to receiving an indication that the radio connection is suspended from the RAN; wherein the release is in response to receiving an indication that the radio connection is resumed from the RAN.

[0352] Example 4. The method according to Example 3, wherein: an indication that the radio connection is suspended is received from a source base station; and an indication that the radio connection is resumed is received from a target base station.

[0353] Example 5. The method according to Example 1, further comprising: sending a new preferred configuration to the RAN by processing hardware, wherein the release is in response to generating the new preferred configuration.

[0354] Example 6. The method according to Example 5, wherein: the preferred configuration is sent to a source base station; and the new preferred configuration is sent to a target base station.

[0355] Example 7. The method according to Example 1, wherein the release is in response to a command for releasing a preferred configuration of the RAN.

[0356] Example 8. The method according to Example 7, wherein: the UE operates in a dual connection (DC) with a master node (MN) and a secondary node (SN), and receives a command for releasing a preferred configuration from the MN.

[0357] Example 9. The method according to any of the above examples, wherein the preferred configuration indicates at least one of the following: (i) the maximum number of secondary cells (SCells), (ii) the maximum number of multiple-input multiple-output (MIMO) layers, or (iii) the maximum aggregated bandwidth.

[0358] Example 10. The method according to any of the above examples, further comprising: generating a preferred configuration by processing hardware in response to detecting overheating.

[0359] Example 11. A method in a distributed unit (DU) of a non-aggregated base station comprising a DU and a central unit (CU), the method comprising: receiving, by processing hardware, from the CU a preferred configuration representing a maximum allocation preferred by the UE for at least one resource; generating, by processing hardware and using the preferred configuration, a DU configuration of the UE; and sending, by processing hardware, the DU configuration to the CU.

[0360] Example 12. The method according to Example 11, wherein: the non-aggregated base station is a master node (MN), and the UE operates in a dual connection (DC) with the MN and a secondary node (SN).

[0361] Example 13. The method according to Example 11, wherein the UE performs a handover procedure, wherein the non-aggregated base station is the source base station.

[0362] Example 14. The method according to Example 11, wherein the UE performs a handover procedure, wherein the non-aggregated base station is the target base station.

[0363] Example 15. The method according to Example 14, wherein: receiving the preferred configuration includes receiving a request for establishing a context for the UE.

[0364] Example 16. The method according to Example 15, wherein: the preferred configuration is a first preferred configuration; the method further comprises: receiving a second preferred configuration from the UE.

[0365] Example 17. The method according to Example 16, wherein the second preferred configuration is received in a message specifying UE assistance information.

[0366] Example 18. The method according to Example 16, further comprising: sending, by processing hardware, a request to the UE to resume a previously suspended radio connection; wherein the second preferred configuration is received in response to sending the request.

[0367] Example 19. A method in a Central Unit (CU) of a non-aggregated base station comprising a CU and a Distributed Unit (DU), the method comprising: receiving, by processing hardware, a preference configuration indicating a maximum allocation preferred by a UE for at least one resource; and sending, by the processing hardware, an indication of the maximum allocation preferred by the UE to the DU.

[0368] Example 20. The method according to Example 19, comprising receiving the preference configuration from the UE via a radio interface.

[0369] Example 21. The method according to Example 20, wherein the preference configuration is received in a message specifying UE assistance information.

[0370] Example 22. The method according to Example 19, comprising receiving the preference configuration from a source base station, wherein, during a handover procedure, the non-aggregated base station operates as a target base station.

[0371] Example 23. The method according to Example 22, further comprising: sending a request to the source base station to retrieve the context of the UE; and wherein the preference configuration is received in response to the request.

[0372] Example 24. The method according to Example 19, further comprising: receiving, from the DU, a conditional DU configuration that meets the maximum allocation preferred by the UE; and sending the conditional DU configuration to the UE, wherein the UE connects to the DU according to the conditional DU configuration when one or more conditions for connecting to the DU are met.

[0373] Example 25. The method according to Example 19, further comprising: sending a conditional configuration to the UE before receiving the preference configuration, wherein the UE connects to the non-aggregated base station according to the conditional configuration when one or more conditions for connecting to the non-aggregated base station are met; and releasing the preference configuration in response to determining that the conditional configuration does not meet the preference configuration.

[0374] Example 26. The method according to Example 19, further comprising: sending a conditional DU configuration to the UE before receiving the preference configuration, wherein the UE connects to the DU according to the conditional DU configuration when one or more conditions for connecting to the DU are met; generating a new conditional DU configuration that meets the preference configuration in response to determining that the conditional configuration does not meet the preference configuration; and sending the new conditional DU configuration to the UE.

[0375] Example 27. The method according to Example 19, further comprising: sending a conditional DU configuration to the UE before receiving the preference configuration, wherein the UE connects to the DU according to the conditional DU configuration when one or more conditions for connecting to the DU are met; retaining the preference configuration in response to determining that the conditional configuration does not meet the preference configuration; and applying the preference configuration in response to the UE connecting to the DU.

[0376] Example 28. A method for managing the configuration of a secondary node (SN) in a master node (MN) when a UE operates with the MN and the SN in a dual connection (DC), the method comprising: determining, by processing hardware and using the capabilities of at least one of the UE or the SN, whether the SN receives an indication of a maximum allocation preferred by the UE for at least one resource; and providing the indication to the SN in response to determining that the SN will receive the indication.

[0377] Example 29. The method according to Example 28, wherein providing the indication to the SN comprises: receiving, by processing hardware, a preferred configuration information element (IE) from the UE, the preferred configuration IE comprising the indication; and sending the indication to the SN by processing hardware.

[0378] Example 30. The method according to Example 29, wherein sending the indication comprises forwarding the preferred configuration IE to the SN.

[0379] Example 31. The method according to Example 30, wherein determining comprises: determining that the SN supports the preferred configuration IE.

[0380] Example 32. The method according to Example 29, wherein sending the indication comprises: generating a second IE of a type other than the preferred configuration IE; including the indication in the second IE; and sending the second IE to the SN by processing hardware.

[0381] Example 33. The method according to Example 29, further comprising: determining, by processing hardware, that the SN is a legacy base station that does not support the preferred configuration IE.

[0382] Example 34. The method according to Example 29, wherein providing the indication to the SN comprises: sending, by processing hardware, to the UE that the UE will send an indication to the SN via a radio interface between the UE and the SN.

[0383] Example 35. The method according to Example 34, wherein determining comprises: using the capabilities of the UE to determine that the UE is capable of sending a preferred UE to the SN, the preferred configuration IE comprising the indication.

[0384] Example 36. The method according to Example 34, wherein determining comprises: using the capabilities of the SN to determine that the SN supports the preferred configuration IE.

[0385] Example 37. The method according to Example 28, further comprising: in a second instance, in response to determining that the SN does not receive the indication: sending, by processing hardware, a request to release the SN from the DC to the SN.

[0386] Example 38. A method for managing a preferred configuration indicating a preferred maximum allocation of at least one resource in a user equipment (UE), where the UE operates in a dual connection (DC) with a master node (MN) and a secondary node (SN), the method comprising: sending the preferred configuration to the MN or the SN by processing hardware; receiving an indication to release the SN by processing hardware; disconnecting from the SN in response to the indication; and releasing the preferred configuration by processing hardware.

[0387] Example 39. The method according to Example 38, wherein the release is in response to a command to reconfigure a radio connection, the command including an indication to release the SN.

[0388] Example 40. The method according to Example 38, wherein the preferred configuration is sent to the MN.

[0389] Example 41. The method according to Example 38, wherein the preferred configuration is sent to the SN.

[0390] Example 42. The method according to Example 38, further comprising: retaining the preferred configuration by processing hardware in response to an indication to release the SN; and releasing the preferred configuration in response to generating a new preferred configuration.

[0391] Example 43. The method according to Example 42, further comprising: sending the new preferred configuration to the MN by processing hardware.

[0392] Example 44. The method according to Example 43, wherein the new preferred configuration is sent in a UE assistance information message.

[0393] Example 45. The method according to Example 38, wherein: the SN is a first SN and the preferred configuration is a first preferred configuration; the method further comprising: receiving mobility information of a second cell group (SCG) of a second SN from the MN by processing hardware during or after sending the first preferred configuration; and determining whether to send a second preferred configuration to the first SN or the second SN based on the mobility information.

[0394] Example 46. The method according to Example 45, further comprising: being able to directly transmit the second preferred configuration to the first SN or the second SN according to the mobility information.

[0395] Example 47. The method according to Example 45, further comprising: disabling direct transmission of the second preferred configuration to the first SN or the second SN according to the mobility information.

[0396] Example 48. The method according to any one of Examples 45 to 47, wherein the second preferred configuration is the same as the first preferred configuration.

[0397] Example 49. A user equipment (UE) comprising processing hardware and configured to implement the method according to any one of Examples 1 - 10 or 38 - 48.

[0398] Example 50. A base station includes processing hardware and is configured to implement the method of any one of Examples 11-37.

Claims

1. A method performed by a master node MN for managing the configuration of a UE when the UE operates in a dual connection DC with the MN and a source secondary node SN, the method comprising: Receiving, by the MN and from the source SN or the UE, a UE assistance information message, the UE assistance information message including a preferred power saving configuration indicating a preferred maximum allocation of the UE for at least one resource; Determining, by the MN, to initiate a process for changing the UE from the source SN to a target SN; And In response to the determination, sending, by the MN and to the target SN, the preferred power saving configuration.

2. The method according to claim 1, wherein: The preferred power saving configuration is one of a plurality of preferred configurations indicating a preferred corresponding maximum allocation of the UE for at least one resource; The UE assistance information message includes a plurality of preferred configurations; and The method further comprises, in response to the determination, sending, by the MN, the plurality of preferred configurations to the target SN.

3. The method according to claim 2, wherein The plurality of preferred configurations include corresponding preferred configurations for each of at least one of the following: uplink and downlink, discontinuous reception DRX, fifth generation 5G, dual connection DC, or sidelink communication.

4. The method according to any one of claims 1-3, wherein The UE assistance information message includes an information element IE containing the preferred power saving configuration.

5. The method according to claim 4, wherein The IE is a CG-Config IE.

6. The method according to any one of claims 1-3, wherein Receiving the UE assistance information message includes: receiving one of an SN change request message, an SN modification request message, or an SN modification request confirmation message including the UE assistance information message.

7. The method according to any one of claims 1-3, wherein, Sending the preferred power saving configuration includes: sending an SN addition request including the preferred power saving configuration.

8. The method according to claim 7, wherein The SN addition request includes the capabilities of the UE.

9. The method according to claim 7, further comprising: Determining, by the MN, that the target SN is a legacy base station that does not support the preferred power saving configuration.

10. The method according to claim 9, wherein, The SN addition request includes an IE corresponding to a format readable by the target SN for the conversion of the preferred power saving configuration.

11. The method according to any one of claims 1-3, wherein, The preferred power saving configuration indicates at least one of the following: (i) The maximum number of secondary cells SCell, (ii) The maximum number of multiple input multiple output MIMO layers, or (iii) The maximum aggregation bandwidth.

12. A method performed by a source secondary node SN for managing the configuration of a UE when the UE operates in a dual connection DC with a master node MN and the source SN, the method comprising: Receiving, by the source SN from the UE, a preferred power saving configuration indicating a preferred maximum allocation of the UE for at least one resource; And After the MN initiates a process for changing the UE from the source SN to a target SN, sending, by the source SN via the MN, a UE assistance information message including the preferred power saving configuration to the target SN.

13. The method according to claim 12, wherein, The UE assistance information message includes a plurality of preferred configurations indicating a preferred corresponding maximum allocation of the UE for at least one resource, the plurality of preferred configurations being received by the source SN from the UE and including the preferred power saving configuration.

14. The method according to claim 13, wherein, The plurality of preferred configurations include corresponding preferred configurations for each of at least one of the following: uplink and downlink, discontinuous reception DRX, fifth generation 5G, dual connection DC, or sidelink communication.

15. The method according to any one of claims 12 - 14, wherein The UE assistance information message includes an information element IE containing the preferred power saving configuration.

16. The method according to claim 15, wherein, The IE is a CG-Config IE.

17. The method according to any one of claims 12-14, wherein, Sending the UE assistance information message includes sending one of an SN change requirement message, an SN modification requirement message, or an SN modification request confirmation message including the UE assistance information message.

18. The method according to any one of claims 12-14, wherein, Receiving the preferred power saving configuration indicates that the UE has determined to change to power saving.

19. The method according to any one of claims 12 - 14, wherein The preferred power saving configuration indicates at least one of the following: (i) The maximum number of secondary cells (SCells), (ii) The maximum number of multiple-input multiple-output (MIMO) layers, or (iii) The maximum aggregation bandwidth.

20. A base station includes processing hardware and is configured to implement the method according to any one of claims 1-3 and 12-14. The processing hardware includes at least one of the following: a radio resource control (RRC) controller or a radio link control (RLC) controller.

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