Managing DAPS Configuration

Abstract

To manage a power coordination configuration when performing a dual active protocol stack (DAPS) procedure, a UE receives (702A) a power coordination configuration from a radio access network (RAN) for the UE to apply when communicating with a source cell and a target cell of the RAN to constrain uplink power; initiates (704A) a DAPS procedure based on the power coordination configuration; and releases (706A) the power coordination configuration in response to detecting a trigger condition.

Description

Technical Field

[0001] The present disclosure relates generally to wireless communications, and more particularly to managing configurations at a user equipment (UE) and a radio access network (RAN). Background Art

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

[0003] In a telecommunications system, the Packet Data Convergence Protocol (PDCP) sublayer of the wireless protocol stack provides services such as user plane data transmission, encryption, integrity protection, etc. For example, the PDCP layer defined for the Evolved Universal Terrestrial Radio Access (EUTRA) radio interface (see 3GPP specification TS 36.323) and the New Radio (NR) (see 3GPP specification TS 38.323) provides sequencing of protocol data units (PDUs) in the uplink direction (from user equipment, also known as user equipment (UE), to the base station) and the downlink direction (from the base station to the UE). In addition, the PDCP sublayer provides services for signaling radio bearers (SRBs) to the radio resource control (RRC) sublayer. The PDCP sublayer also provides data radio bearer (DRB) services to the service data adaptation protocol (SDAP) sublayer or protocol layers such as the Internet Protocol (IP) layer, the Ethernet protocol layer, and the Internet Control Message Protocol (ICMP) layer. In general, the UE and the base station can use SRBs to exchange RRC messages and non-access stratum (NAS) messages, and can use DRBs to transmit data on the user plane.

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

[0005] In some scenarios, the UE can simultaneously utilize the resources of multiple nodes (e.g., base stations or components of distributed base stations) of a radio access network (RAN) interconnected by a backhaul. When these network nodes support different radio access technologies (RATs), this type of connectivity is called multi-radio dual connectivity (MR-DC). When the UE operates in MR-DC, one base station operates as a MN covering a primary cell (PCell), and the other base station operates as a SN covering a primary secondary cell (PSCell). The UE communicates with the MN (via the PCell) and the SN (via the PSCell). In other scenarios, the UE utilizes the resources of one base station at a time. A base station and / or the UE determines that the UE should establish a radio connection with another base station. For example, a base station may determine to switch the UE to a second base station and initiate a switching process. In other scenarios, the UE can simultaneously utilize the resources of a RAN node (e.g., a single base station or a component of a distributed base station), which is interconnected with other network elements via a backhaul.

[0006] Documents 3GPP TS 36.300 v16.0.0, 38.300 v16.0.0 and 38.401 v16.1.0 describe certain procedures related to handover or "reconfiguration with synchronization" scenarios. These procedures involve messaging (e.g., RRC signaling and preparation) between the RAN node and the UE. A UE may perform a handover procedure to switch from one cell to another, whether in single connectivity (SC) or DC or other types of multi-connectivity operation. Depending on the scenario, the UE may switch from a cell of a serving base station to a target cell of a target base station, or from a cell of a first distributed unit (DU) of a serving base station to a target cell of a second DU of the same base station.

[0007] Document 3GPP TS 37.340 v16.0.0 describes certain procedures for a UE to change PSCell in a DC scenario. These procedures involve messaging (e.g., RRC signaling and preparation) between RAN nodes and the UE. Depending on the scenario, the UE may perform a PSCell change from a PSCell of a serving SN to a target PSCell of a target SN or from a PSCell of a source distributed unit (DU) of a base station to a PSCell of a target DU of the same base station.

[0008] Recently, 3GPP has been discussing and standardizing new technologies, including for Release 16 (Rel-16) specifications, such as 3GPP specifications 38.331v16.0.0 and 36.331v16.0.0. The new technologies include dual active protocol stack (DAPS) switching and DAPSP SSCell change procedures, which are used to achieve 0ms user data interruption during switching and PSCell change, respectively. Typically, the length of the interruption experienced at the UE depends on the time difference between the time when the radio link connection at the source cell is released and the time when the radio link connection at the target cell is established. If the release time is not earlier than the establishment time, it is possible to achieve 0ms user data interruption. Using DAPS, when performing DAPS switching and DAPS PSCell change, the UE can communicate with the source cell while the target cell establishes a radio link connection, and then stop communicating with the source cell after the target cell establishes the radio link connection.

[0009] In some cases, the RAN may provide a DAPS power coordination configuration (e.g., daps-PowerCoordinationInfo-r16) to the UE so that the UE performs a DAPS handover or a DAPS PSCell change. The DAPS power coordination configuration typically indicates the maximum power that the UE can transmit on the source PCell and the maximum power that the UE can transmit on the target PCell. The DAPS power coordination configuration may also indicate the power control mode used by the UE during the DAPS handover. Upon receiving the DAPS power coordination configuration, the UE configures its lower layers (e.g., the physical layer) to apply the DAPS power coordination configuration. However, in some of these scenarios, the UE and / or the RAN may incorrectly handle the DAPS power coordination configuration, causing the UE to unnecessarily limit its maximum uplink power. As a result, in some situations, such as cell edge situations, the RAN may not receive transmissions from the UE, and the UE may experience a radio link failure, which causes service interruption.

[0010] In some cases, when a radio link failure is detected while communicating with a source base station of the RAN using a configuration, the UE may suspend the configuration and initiate an RRC connection re-establishment procedure with a target base station of the RAN. However, in some cases, when the UE attempts to resume the configuration with the target base station, a communication error may occur between the UE and the target base station, such as when the target base station does not support a configuration that is otherwise supported by the source base station. Summary of the invention

[0011] In general, a UE and one or more base stations operating in a RAN implement the techniques of the present disclosure to prepare the UE to perform a DAPS procedure (i.e., DAPS handover, DAPS PSCell change). For example, using these techniques, the RAN may provide a DAPS power coordination configuration to the UE to limit the maximum power that the UE can transmit on the source PCell and the target PCell when performing the DAPS procedure. In order to prevent the UE from performing unnecessary communications with the target PCell according to the DAPS power coordination configuration after the UE successfully performs the DAPS procedure, the UE releases the DAPS power coordination configuration. The UE may release the DAPS power coordination configuration in response to: (a) successfully performing a DAPS procedure; (b) receiving a DAPS release indicator from the RAN after successfully performing the DAPS procedure; or (c) failing to successfully perform the DAPS procedure.

[0012] An example embodiment of these techniques is a method in a UE for managing a power coordination configuration when performing a DAPS procedure. The method is implemented using processing hardware and includes: receiving a power coordination configuration from a RAN for the UE to apply when communicating with a source cell and a target cell of the RAN to constrain uplink power; initiating a DAPS procedure according to the power coordination configuration; and releasing the power coordination configuration in response to detecting a trigger condition.

[0013] Another example embodiment of these techniques is a method in a RAN for managing a power coordination configuration when performing a DAPS procedure with a UE. The method is implemented using processing hardware and includes: determining, based on the power coordination configuration, that the UE is to perform a DAPS procedure to connect to a target cell and disconnect from a source cell after connecting to the target cell; transmitting the power coordination configuration to the UE for the UE to apply when communicating with the source cell and the target cell to constrain uplink power; and causing the UE to release the power coordination configuration in response to detecting a trigger condition.

[0014] Yet another embodiment of the techniques is a base station comprising processing hardware and configured to implement one of the methods described above.

[0015] Another embodiment of the techniques is a UE comprising processing hardware and configured to implement one of the methods described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1A is a block diagram of an example system in which a RAN and a UE may implement techniques of this disclosure for managing configuration when performing a DAPS handover, DAPS PSCell change, or RRC re-establishment procedure.

[0017] Figure 1B is a block diagram of an example base station in which a centralized unit (CU) and a distributed unit (DU) may be Figure 1A Operate in a system

[0018] Figure 2 is a block diagram of an example protocol stack, according to which, Figure 1A The UE can be connected with Figure 1A Base station communication;

[0019] Figure 3A and Figure 3B is a message sending diagram for an example scenario, wherein the RAN prepares the UE for a DAPS handover procedure by providing the UE with a DAPS power coordination configuration;

[0020] Figure 4A and Figure 4Bis a messaging diagram for an example scenario, where the RAN prepares the UE for a DAPS PSCell change procedure by providing the UE with a DAPS power coordination configuration;

[0021] Figure 5A is a flow chart of an example scenario in which the UE stops an application and releases a DAPS power coordination configuration in response to receiving a message from the RAN;

[0022] Figure 5B is a flow chart of another example scenario, in which the UE stops and releases the DAPS power coordination configuration after performing a random access procedure with the RAN;

[0023] Figure 5C is a flow chart of another example scenario in which the UE stops and releases the DAPS power coordination configuration after determining that DAPS operation with the RAN has failed;

[0024] Figure 6 is a flow chart of an example scenario in which the RAN provides a DAPS power coordination configuration to a UE and later releases the DAPS power coordination configuration;

[0025] Fig. 7A is a flow chart of an example method in which a UE manages power coordination configuration while performing a DAPS procedure with a RAN; and

[0026] Figure 7B is a flow chart of an example method in which a RAN manages power coordination configuration while performing a DAPS procedure with a UE. DETAILED DESCRIPTION

[0027] Figure 1A An example wireless communication system 100 is depicted in which the configuration handling techniques of the present disclosure may be implemented, such as when performing a DAPS handover, a DAPS PSCell change, or an RRC re-establishment procedure. The wireless communication system 100 includes a UE 102 and a RAN 105 (e.g., base stations 104, 106A, 106B) connected to a core network (CN) 110. For example, the base stations 104, 106A, 106B may be any suitable type or types of base stations, such as an evolved Node B (eNB), a next generation eNB (ng-eNB), or a 5G Node B (gNB). As a more specific example, the base station 104 may be an eNB or a gNB, and the base stations 106A and 106B may be gNBs.

[0028] Base station 104 supports cell 124, base station 106A supports cell 126A, and base station 106B supports cell 126B. Cell 124 partially overlaps with both cells 126A and 126B, so that UE 102 can be within range of communication with base station 104 while being within range of communication with base station 106A or 106B (or within range of detecting or measuring signals from both base stations 106A or 106B, etc.). For example, the overlap can enable UE 102 to switch between cells (e.g., from cell 124 to cell 126A or 126B) or base stations (e.g., from base station 104 to base station 106A or base station 106B) before UE 102 experiences a radio link failure. In addition, the overlap allows various dual connectivity (DC) scenarios discussed below. For example, UE 102 may communicate in DC with base station 104 (operating as a MN) and base station 106A (operating as a SN), and upon completing a handover, may communicate with base station 106B (operating as a MN). As another example, UE 102 may communicate in DC with base station 104 (operating as a MN) and base station 106A (operating as a SN), and upon completing an SN change, may communicate with base station 104 (operating as a MN) and base station 106B (operating as a SN).

[0029] More specifically, when UE 102 is in DC with base station 104 and base station 106A, base station 104 operates as a master eNB (MeNB), a master ng-eNB (Mng-eNB), or a master gNB (MgNB), and base station 106A operates as a secondary gNB (SgNB) or a secondary ng-eNB (Sng-eNB). In embodiments and scenarios where UE 102 is in SC with base station 104 but is capable of DC operation, base station 104 operates as a MeNB, Mng-eNB, or MgNB, and base station 106A operates as a candidate SgNB (C-SgNB) or a candidate Sng-eNB (C-Sng-eNB). Although various scenarios are described below in which base station 104 operates as a MN and base station 106A (or 106B) operates as a SN or T-SN, in different scenarios, any of base stations 104, 106A, 106B may generally operate as a MN, SN, or T-SN. Thus, in some embodiments, base station 104, base station 106A, and base station 106B may implement a similar set of functions and each support MN, SN, and T-SN operations.

[0030] In operation, UE 102 may use radio bearers (e.g., DRBs or SRBs) that terminate at different times at a MN (e.g., base station 104) or a SN (e.g., base station 106A). For example, after handover to base station 106B, UE 102 may use radio bearers (e.g., DRBs or SRBs) that terminate at different times at base station 106B. UE 102 may apply one or more security keys when communicating on the radio bearers in the uplink (from UE 102 to base station) and / or downlink (from base station to UE 102) directions.

[0031] Base station 104 includes processing hardware 130, which may include: one or more general purpose processors (eg, central processing units (CPUs)); and computer readable memory storing machine readable instructions executable on one or more general purpose processors and / or special purpose processing units. Figure 1A The processing hardware 130 in the example implementation of 104 includes a base station RRC controller 132, which is configured to manage or control RRC configuration and RRC procedures. For example, the base station RRC controller 132 can be configured to support RRC messaging associated with DAPS handover and DAPS PSCell change procedures, re-establishment procedures, recovery procedures, and / or support necessary operations when the base station 104 operates as a MN, as described below.

[0032] The base station 106A includes processing hardware 140, which may include one or more general purpose processors (eg, CPUs) and computer readable memory storing machine readable instructions executable on the general purpose processors and / or special purpose processing units. Figure 1A The processing hardware 140 in the example implementation includes a base station RRC controller 142, which is configured to manage or control RRC configuration and RRC procedures. For example, the base station RRC controller 142 can be configured to support RRC message transmission associated with DAPS handover and DAPS PSCell change procedures, re-establishment procedures, recovery procedures, and / or support necessary operations when the base station 106A operates as a SN or a target SN (T-SN), as described below. Although not described in Figure 1A 1 , but base station 106B may include processing hardware similar to processing hardware 140 of base station 106A.

[0033] UE 102 includes processing hardware 150, which may include one or more general-purpose processors (eg, CPUs) and computer-readable memory storing machine-readable instructions executable on the general-purpose processors and / or special-purpose processing units. Figure 1AThe processing hardware 150 in the example embodiment includes a UE RRC controller 152, which is configured to manage or control RRC configuration RRC procedures. For example, according to any of the embodiments discussed below, the UE RRC controller 152 can be configured to support RRC messaging associated with DAPS handover and DAPS PSCell change procedures and / or re-establishment procedures.

[0034] CN 110 may be an evolved packet core (EPC) 111 or a fifth generation core (5GC) 160, both of which are Figure 1A . The base station 104 may be an eNB supporting an S1 interface for communicating with the EPC 111, an ng-eNB supporting an NG interface for communicating with the 5GC 160, or a gNB supporting an NR radio interface and an NG interface for communicating with the 5GC 160. The base stations 106A, 106B may each be an EN-DC gNB (en-gNB) having an S1 interface to the EPC 111, an en-gNB not connected to the EPC 111, a gNB supporting an NR radio interface and an NG interface to the 5GC 160, or an ng-eNB supporting an EUTRA radio interface and an NG interface to the 5GC 160. In order to exchange messages directly with each other during the scenarios discussed below, the base stations 104, 106A, and 106B may support an X2 or Xn interface.

[0035] The EPC 111 may include a serving gateway (S-GW) 112 and a mobility management entity (MME) 114, among other components. The S-GW 112 is typically configured to transmit user plane packets associated with 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 and an access and mobility management (AMF) 164, and / or a session management function (SMF) 166. The UPF 162 is typically configured to transmit user plane packets associated with 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.

[0036] In general, the wireless communication network 100 may include any suitable number of base stations supporting NR cells and / or EUTRA cells. For example, base station 104 and base station 106A may also support cells 122 and 123, respectively. More specifically, EPC 111 or 5GC 160 may be connected to any suitable number of base stations supporting NR cells and / or EUTRA cells. Although the following examples specifically relate to specific CN types (EPC, 5GC) and RAT types (5G NR and EUTRA), in general, the technology of the present disclosure may also be applied to, for example, 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.

[0037] As described above, the wireless communication system 100 may support various procedures (eg, DAPS handover, DAPS PSCell change, re-establishment, etc.) and operation modes (eg, SC or DC). Example operations of various procedures that may be implemented in the wireless communication system 100 will now be described.

[0038] In some embodiments, the wireless communication system 100 supports a conventional handover preparation procedure (i.e., a non-DAPS handover preparation procedure). For example, in one scenario, for example, the base station 104 may perform a non-DAPS handover preparation procedure to configure the UE 102 to be handed over from the cell 124 of the base station 104 to the cell 126A of the base station 106A. In this scenario, the base station 104 and the base station 106A operate as a source base station (S-BS) or a source MN (S-MN) and a target base station (T-BS) or a target MN (T-MN), respectively. In the non-DAPS handover preparation procedure, the base station 104 sends a handover request (Handover Request) message to the base station 106A. In response to the handover request message, the base station 106A includes configuration parameters for configuring radio resources for the UE 102 in a handover command (handover command) message, includes the handover command message in a handover request acknowledgment (Handover Request Acknowledge) message, and sends a handover request acknowledgment message to the base station 104. In turn, base station 104 transmits a handover command message to UE 102 and subsequently suspends (or stops) sending or receiving data to or from UE 102.

[0039] When receiving the handover command message, UE 102 switches to base station 106A via cell 126A and communicates with base station 106A by using the configuration parameters in the handover command message. Specifically, in response to the handover command message, UE 102 disconnects from cell 124 (or base station 104), performs a random access procedure with base station 106A via cell 126A, and transmits a handover complete message to base station 106A via cell 126A.

[0040] In some embodiments, the wireless communication system 100 supports a DAPS handover preparation procedure. In one scenario, for example, the base station 104 may perform a DAPS handover preparation procedure to configure the UE 102 to handover from the cell 124 of the base station 104 to the cell 126B of the base station 106B. In this scenario, the base station 104 and the base station 106B operate as an S-BS or S-MN and a T-BS or T-MN, respectively. In the DAPS handover preparation procedure, the base station 104 sends a handover request message to the base station 106B. In some embodiments, the base station 104 may explicitly request a DAPS handover in the handover request message, for example, by including a DAPS indicator in the handover request message. In response to the handover request message and in order to accept the request for DAPS handover, the base station 106B includes configuration parameters for configuring radio resources for the UE 102 in the handover command, includes a handover command message in the handover request confirmation message, and sends a handover request confirmation message to the base station 104. In some implementations, the base station 106B may indicate a DAPS handover in the handover command message, for example, by including a DAPS configuration or DAPS indicator in the handover command message, or may include an indicator in the handover request confirm message. In turn, the base station 104 transmits the handover command message to the UE 102.

[0041] When receiving the handover command message, UE 102 performs a DAPS handover procedure to handover to base station 106B via cell 126B and communicate with base station 106B by using the configuration parameters in the handover command message. Specifically, in response to the handover command message, although UE 102 is disconnected from cell 124 (or base station 104) in the non-DAPS handover procedure, UE 102 maintains connection to base station 104 via cell 124 in the DAPS handover procedure, performs a random access procedure with base station 106B via cell 126B, and transmits a handover completion message to base station 106B via cell 126B.

[0042] While maintaining the connection to the base station 104 via the cell 124 during the DAPS handover process, the UE 102 effectively has two links, i.e., a source MCG link with the base station 104 and a target MCG link with the base station 106B. The UE 102 may continue to receive data (i.e., downlink data) from the base station 104 until the UE 102 receives an indication from the base station 106B to release the source MCG link with the base station 104. The UE 102 may continue to transmit data (e.g., a new uplink data transmission or a retransmission of a PDCP SDU) to the base station 104 until the UE 102 successfully completes the random access procedure with the base station 106B or receives an indication from the base station 106B to release the MCG link with the base station 104.

[0043] In some embodiments, in the above handover preparation process scenario, the wireless communication system 100 supports DC operation. For example, in one scenario, for example, after UE 102 is connected to base station 104, base station 104 performs an SN addition process to add base station 106A as an SN, thereby configuring UE 102 to operate in DC with base stations 104 and 106A. At this time, base stations 104 and 106A operate as MN and SN, respectively. Later, MN 104 can initiate a non-DAPS or DAPS handover preparation process to handover UE 102 to T-MN 106B.

[0044] In some embodiments, the wireless communication system 100 supports a conventional PSCell change preparation procedure (i.e., a non-DAPS PSCell change preparation procedure). For example, in one scenario, the UE 102 is initially in DC with the MN 104 (e.g., via the PCell 124) and the SN 106A (via the PSCell 123). The SN 106A may provide the UE 102 with a configuration for the T-PSCell 126A. The UE 102 stops communicating with the SN 106A via the PSCell 123, and attempts to connect to the T-PSCell 126A after receiving the configuration for the T-PSCell 126A. In another scenario, for example, when UE 102 is in DC with MN 104 and SN 106A, as part of a non-DAPS PSCell change procedure, MN 104 determines to change the SN of UE 102 from base station 106A (which may be referred to as a source SN or S-SN) to base station 106B (which may be referred to as a target SN or T-SN). UE 102 stops communicating with S-SN 106A via PSCell 123, and after receiving a configuration for T-PSCell 126B, attempts to connect to T-SN 106B via T-PSCell 126B.

[0045] In some embodiments, the wireless communication system 100 supports DAPS PSCell changes. For example, in one scenario, the UE 102 is initially in DC with the MN 104 (e.g., via the PCell 124) and the SN 106A (via the PSCell 123). The SN 106A may provide the UE 102 with a configuration for the T-PSCell 126A. The UE 102 continues to communicate with the SN 106A via the PSCell 123 while simultaneously attempting to connect to the T-PSCell 126A after receiving the configuration for the T-PSCell 126A. After the T-PSCell 126A begins operating as the PSCell 126A for the UE 102, the UE 102 stops communicating with the SN 106A via the PSCell 123. In another scenario, for example, when UE 102 is in DC with MN 104 and SN 106A, MN 104 determines to change the SN of UE 102 from base station 106A (which may be referred to as a source SN or S-SN) to base station 106B (which may be referred to as a target SN or T-SN) as part of a DAPS PSCell change procedure. UE 102 continues to communicate with S-SN 106A via PSCell 123, while at the same time, after receiving a configuration for T-PSCell 126B, attempts to connect to T-SN 106B via T-PSCell 126B. After T-PSCell 126B begins operating as PSCell 126B for UE 102, UE 102 stops communicating with S-SN 106A via PSCell 123.

[0046] In different configurations or scenarios of the wireless communication system 100, the base station 104 can operate as a MeNB, Mng-eNB, or MgNB, the base station 106B can operate as a MeNB, Mng-eNB, MgNB, SgNB, or Sng-eNB, and the base station 106A can operate as an SgNB or Sng-eNB. The UE 102 can communicate with the base station 104 and the base stations 106A or 106B via the same radio access technology (RAT) such as EUTRA or NR, or via different RATs.

[0047] When the base station 104 is a MeNB and the base station 106A is an SgNB, the UE 102 may be in EUTRA-NR DC (EN-DC) with the MeNB 104 and the SgNB 106A. When the base station 104 is a Mng-eNB and the base station 106A is an SgNB, the UE 102 may be in Next Generation (NG) EUTRA-NR DC (NGEN-DC) with the Mng-eNB 104 and the SgNB 106A. When the base station 104 is a MgNB and the base station 106A is an SgNB, the UE 102 may be in NR-NR DC (NR-DC) with the MgNB 104 and the SgNB 106A. When the base station 104 is a MgNB and the base station 106A is an Sng-eNB, the UE 102 may be in NR-EUTRA DC (NE-DC) with the MgNB 104 and the Sng-eNB 106A.

[0048] Figure 1B An exemplary distributed implementation of any one or more of the base stations 104, 106A, 106B is depicted. In this implementation, the base station 104, 106A, or 106B includes a centralized unit (CU) 172 and one or more distributed units (DUs) 174. The CU 172 includes processing hardware such as one or more general-purpose processors (e.g., CPUs), and a computer-readable memory storing machine-readable instructions executable on the general-purpose processors and / or special-purpose processing units. For example, the CU 172 may include Figure 1A The processing hardware 130 or 140. The processing hardware may include a base station RRC controller (e.g., RRC controller 142) configured to manage or control one or more RRC configurations and / or RRC processes when the base station (e.g., base station 106A) operates as a SN.

[0049] Each of the DUs 174 also includes processing hardware that may include one or more general purpose processors (e.g., CPUs) and computer readable memory storing machine readable instructions executable on the one or more general purpose processors and / or special purpose processing units. For example, the processing hardware may include a medium access control (MAC) controller configured to manage or control one or more MAC operations or processes (e.g., random access processes), and a radio link control (RLC) controller configured to manage or control one or more RLC operations or processes when the base station (e.g., base station 106A) operates as a MN or SN. The processing hardware may also include a physical layer controller configured to manage or control one or more physical layer operations or processes.

[0050] Figure 2An example dual-active protocol stack (DAPS) 200 is shown in a simplified manner, according to which the UE 102 can communicate with an eNB / ng-eNB or gNB (e.g., one or more of the base stations 104, 106A, 106B).

[0051] In the example stack 200, the physical layer (PHY) 202A of EUTRA provides transport channels to the EUTRA MAC sublayer 204A, which in turn provides logical channels to the EUTRA RLC sublayer 206A. The EUTRA RLC sublayer 206A in turn provides RLC channels to the EUTRA PDCP sublayer 208, and in some cases, to the NR PDCP sublayer 210. Similarly, the NR RPHY 202B provides transport channels to the NR MAC sublayer 204B, which in turn provides logical channels to the NR RLC sublayer 206B. The NR RLC sublayer 206B in turn provides RLC channels to the NR PDCP sublayer 210. In some embodiments, the UE 102 supports the following: Figure 2 Both the EUTRA and NR stacks shown are provided to support handover between EUTRA and NR base stations and / or to support DC on the EUTRA and NR interfaces. Figure 2 As shown, the UE 102 can support layering of NR PDCP 210 on EUTRA RLC 206A.

[0052] The EUTRA PDCP sublayer 208 and the NR PDCP sublayer 210 receive packets, which may be referred to as service data units (SDUs) (e.g., from an Internet Protocol (IP) layer, layered directly or indirectly on the PDCP layer 208 or 210), and output packets, which may be referred to as protocol data units (PDUs) (e.g., to the RLC layer 206A or 206B). Except where the difference between SDUs and PDUs is relevant, for simplicity, this disclosure refers to SDUs and PDUs as "packets."

[0053] For example, on the control plane, the EUTRA PDCP sublayer 208 and the NR PDCP sublayer 210 may provide SRBs to exchange RRC messages. On the user plane, the EUTRA PDCP sublayer 208 and the NR PDCP sublayer 210 may provide DRBs to support data exchange.

[0054] In a scenario where the UE 102 operates in EUTRA / NR DC (EN-DC) with the base station 104 operating as a MeNB and the base station 106A operating as an SgNB, the wireless communication system 100 can provide the UE 102 with MN-terminated bearers using the EUTRA PDCP sublayer 208, or MN-terminated bearers using the NR PDCP sublayer 210. In various scenarios, the wireless communication system 100 can also provide the UE 102 with SN-terminated bearers, which only use the NR PDCP sublayer 210. The MN-terminated bearer can be an MCG bearer or a separated bearer. The SN-terminated bearer can be an SCG bearer or a separated bearer. The MN-terminated bearer can be an SRB (e.g., SRB1 or SRB2) or a DRB. The SN-terminated bearer can be an SRB or a DRB.

[0055] Figure 3A and Figure 3B This corresponds to a DAPS switching scenario, in which the base station initiates a DAPS switching process for the UE. Figure 4A and Figure 4B This corresponds to the DAPS PSCell change scenario, in which the base station initiates the DAPS PSCell change process for the UE. Figure 3A , Figure 3B , Figure 4A and Figure 4B 1 , but it should be appreciated that the following techniques may be implemented by other components and / or systems besides the wireless communication system 100 of FIG. 1 .

[0056] First reference Figure 3A According to DAPS handover scenario 300A, base station 104 operates as a source MN (S-MN) for UE 102, and base station 106B operates as a target MN (T-MN) for UE 102. Base station 104 and base station 106B may be referred to as MNs in both SC and DC scenarios.

[0057] Initially, UE 102 communicates (302A) data (e.g., uplink (UL) data PDUs and / or downlink (DL) data PDUs) with S-MN 104 by using the S-MN configuration. In some scenarios, UE 102 communicates (302A) data in a SC with S-MN 104 or in a SC with S-MN 104. Figure 3A The S-MN 104 (operating as a MN) and the SN (e.g., base station 106A) (not shown) communicate (302A) data in the DC.

[0058] Later, for example, blindly or in response to detecting a suitable event, S-MN 104 determines (304A) to initiate DAPS handover for T-MN 106B and UE 102 to communicate. For example, the determination of the event (304A) may occur in response to S-MN 104 receiving one or more measurement report results from UE 102 that are above (or below) one or more predetermined thresholds, or calculating (from the measurement results) filtering results that are above (or below) the predetermined thresholds. In another example, the suitable event may be that UE 102 is moving toward T-MN 106B. In yet another example, the suitable event may be that one or more measurement results generated or obtained by S-MN 104 based on measurements of signals received from UE 102 are above (or below) one or more predetermined thresholds.

[0059] After determining (304A) to initiate a DAPS handover, the S-MN 104 sends 312A a handover request message to the T-MN 106B. In some implementations, the handover request message includes an S-MN configuration. In response, the T-MN 106B generates (314A) a handover command message for DAPS handover, the handover command message including a T-MN configuration including a DAPS power coordination configuration (e.g., a DAPS-PowerCoordinationInfo-r16 IE or a DAPS-Configuration-r16 IE); includes the handover command message in a handover request confirmation message, and sends 316A a handover request confirmation message to the S-MN 104. In turn, the S-MN 104 transmits 318A a handover command message to the UE 102. The handover command message also includes one or more random access configurations required for the UE 102 to handover to the T-MN 106B, and in some embodiments, includes additional fields or IEs, such as mobility fields or IEs for the PCell of the T-MN 106B (e.g., mobilityControlInfo field, reconfigurationWithSync field, MobilityControlInfo IE, ReconfigurationWithSyncIE), which may include some or all of the random access configurations. In some embodiments, the T-MN 106B may include a DAPS power coordination configuration in the mobility field or IE.

[0060] In some implementations, the T-MN 106B may include a DAPS configuration (e.g., a daps-Config field or a daps-HO field) in the handover command message indicating that a particular DRB is a DAPS bearer. The DAPS configuration enables the UE 102 to communicate with the S-MN 104 (using the configuration in the S-MN configuration) and the T-MN 106B (using the configuration in the T-MN configuration during and after a successful DAPS handover) using a DAPS for DAPS bearers (e.g., DAPS 200).

[0061] Thus, in response to receiving 318A the handover command message, the UE 102 (e.g., PHY 202) applies (i.e., uses) (352A) the DAPS power coordination configuration and continues (320A) communicating with the S-MN 104 using the S-MN configuration while the UE 102 attempts to handover to the T-MN 106B in accordance with the handover command message. In some implementations, the RRC controller 152 may send DAPS power coordination configuration parameters in the DAPS power coordination configuration to the PHY 202, which in turn applies the DAPS power coordination configuration parameters.

[0062] In attempting to perform a DAPS handover, the UE 102 initiates (322A) a random access procedure with the T-MN 106B via a target cell (e.g., PCell 126B) covered by the T-MN 106B, for example, by using one or more random access configurations in a handover command message received from the S-MN 104 at event 318A. After obtaining access to the channel, during or after successfully completing the random access procedure, the UE 102 sends 324A a handover complete message to the T-MN 106B via the target cell. After the T-MN 106B identifies the UE 102 during the random access procedure (i.e., the UE 102 succeeds in random access contention resolution) or receives 324A the handover complete message, the UE 102 communicates (326A) control signals and data (e.g., UL data PDUs or DL ​​data PDUs) with the T-MN 106B via the target cell by using the configuration indicated in the handover command message. T-MN 106B sends 328A a Handover Success message to S-MN 104. After receiving the Handover Success message, S-MN 104 stops (330A) communicating with UE 102.

[0063] The DAPS configuration and / or DAPS power coordination configuration enables the UE 102 to continue to communicate with the S-MN 104 while communicating with the T-MN 106B. Because the UE 102 no longer needs to use DAPS to continue communicating with the S-MN 104 after successfully performing the DAPS handover, the UE 102 can stop 354A applying the DAPS power coordination configuration and release the DAPS power coordination configuration. In this way, when communicating with the T-MN 106B, the UE 102 will not unnecessarily limit its maximum uplink power according to the DAPS power coordination configuration, thereby reducing the chance of radio link failure with the T-MN 106B. In some embodiments, the T-MN 106B can send 332A an RRC reconfiguration message including a DAPS release indicator to the UE 102, for example, via the target cell (e.g., PCell 126B) before, after, or at the same time as transmitting 328A a handover success message. In response to the RRC reconfiguration message or the DAPS release indicator, the UE 102 may stop (354A) applying the DAPS power coordination configuration and release the DAPS power coordination configuration. In some embodiments, after successfully performing (322A) the random access procedure, the UE 102 may stop (354A) applying the DAPS power coordination configuration and release the DAPS power coordination configuration. In some embodiments, the RRC controller 152 may send an indication to the PHY 202 of the UE 102 to cause the PHY 202 to stop applying (354A) the DAPS power coordination configuration.

[0064] In some implementations, the T-MN 106B may also release 356A the DAPS power coordination configuration because the UE 102 no longer needs to use the DAPS power coordination configuration and / or the UE 102 releases (354A) the DAPS power coordination configuration. That is, after including the DAPS power coordination configuration in event 316A in the handover command message, the T-MN 106B may release the DAPS power coordination configuration.

[0065] After event 354A, UE 102 may transmit 334A an RRC reconfiguration complete message to T-MN 106B and cease 336A communications (i.e., UL and / or DL ​​communications) with S-MN 104. In some implementations, in response to the DAPS release indicator, an RF chip, receiver, or transceiver of UE 102 used to communicate with S-MN 104 during the DAPS handover may enter a low power mode, a sleep mode, or shut down completely if the DAPS handover is an inter-frequency DAPS handover.

[0066] In some embodiments, the DAPS power coordination configuration includes one or more of the following DAPS power coordination configuration parameters: a maximum total transmission power (or its value) that the UE 102 can use for uplink communication with the S-MN 104 during DAPS handover (interchangeably referred to as "CP1"), a maximum total transmission power (or its value) that the UE 102 can use for uplink communication with the T-MN 106B during DAPS handover (interchangeably referred to as "CP2"), and / or an uplink power sharing mode used by the UE 102 during DAPS handover (interchangeably referred to as "CP3"). In some embodiments, the DAPS power coordination configuration parameters can be included in a field or IE of the DAPS power coordination configuration. For ease of reading throughout the disclosure, a "configuration" (e.g., a DAPS power coordination configuration) refers to one or more parameters included in the configuration. In addition, one or more "parameters" described herein also refer to values ​​relative to the parameters.

[0067] After UE 102 (e.g., PHY 202) applies the DAPS power coordination configuration during DAPS handover, UE 102 (e.g., PHY 202) may determine (or manage or coordinate) its uplink transmission power for transmission to S-MN 104 and its uplink transmission power for transmission to T-MN 106B according to the DAPS power coordination configuration (e.g., according to 3GPP specification 38.213 v16.1.0 or 36.213 v16.1.0). In some embodiments, if the uplink power sharing mode specified in CP3 is the first mode (e.g., semi-static mode 1), UE 102 manages its uplink transmission power to not exceed CP1 when transmitting (320A) to S-MN 104 and not exceed CP2 when transmitting (326A) to T-MN 106B. In other embodiments, if the uplink power sharing mode is the second mode (e.g., semi-static mode 2 or dynamic mode), and the first uplink transmission to the S-MN 104 partially or completely overlaps with the second uplink transmission to the T-MN 106B, the UE 102 manages the uplink transmission powers of the first uplink transmission and the second uplink transmission so as not to exceed CP1 and CP2, respectively. If the uplink power sharing mode is the second mode, and the first uplink transmission to the S-MN 104 does not overlap with the second uplink transmission to the T-MN 106B, the UE 102 manages the uplink transmission powers of the first uplink transmission and the second uplink transmission so as not to exceed corresponding maximum total transmission power values ​​other than those included in the DAPS power coordination configuration.

[0068] In some implementations, the S-MN 104 and the T-MN 106B may provide these respective maximum total transmission power values ​​in respective non-DAPS configurations to the UE 102. In some implementations, the S-MN 104 may send the non-DAPS configuration to the UE 102 in a broadcast message (e.g., a system information block and / or a dedicated message (e.g., an RRC reconfiguration message)), and the T-MN 106B may send the non-DAPS configuration to the UE 102 in a handover command message or a broadcast message (e.g., a system information block) on the PCell 126B.

[0069] In some embodiments, the T-MN 106B receives configuration restrictions for DAPS handover from the S-MN 104 in a handover request message. The T-MN 106B may generate a DAPS power coordination configuration according to the configuration restrictions. In one embodiment, the S-MN 104 may generate preferred power coordination configuration parameters and include them in the configuration restrictions, and in turn the T-MN 106B may include such preferred parameters in the DAPS power coordination configuration. In one embodiment, the S-MN 104 may determine the preferred parameters based on the UE capabilities of the UE 102. For example, the UE capabilities may indicate or include UE power classes and / or DAPS power sharing modes supported by the UE 102. If the UE capabilities include or otherwise indicate supported uplink power sharing modes, the S-MN 104 may set the preferred uplink sharing mode to one of the supported uplink power sharing modes. If UE 102 is configured to implement all uplink sharing modes supported by RAN 105, S-MN 104 may select a specific preferred uplink sharing mode based on one or more of the following preferred power coordination configuration parameters: UE power class (interchangeably referred to as "PCP1") and / or regulatory requirements (interchangeably referred to as "PCP2").

[0070] Similarly, in another embodiment, the T-MN 106B may determine some or all of the DAPS power coordination configuration parameters in the DAPS power coordination configuration based on the preferred power coordination configuration parameters provided by the S-MN 104 and / or the UE capabilities of the UE 102. If the UE capabilities include or otherwise indicate a supported uplink power sharing mode, the T-MN 106B may set the uplink sharing mode to one of the supported uplink power sharing modes or the preferred uplink sharing mode provided by the S-MN 104. If the UE 102 is configured to implement all uplink sharing modes supported by the RAN 105, the T-MN 106B may select a specific uplink sharing mode based on PCP1, PCP2, and / or the same preferred power coordination configuration parameters provided by the S-MN 104.

[0071] In some embodiments, after successfully completing (322A) the random access procedure, the UE 102 stops transmitting and retransmitting UL data PDUs and / or control signals on a physical uplink control channel (PUCCH) to the S-MN 104. In other embodiments, the UE 102 stops transmitting new UL data PDUs to the S-MN 104, but continues to retransmit UL data PDUs to the S-MN 104 if requested by the S-MN 104 after successfully completing (322A) the random access procedure, until event 336A occurs. In such embodiments, the UE 102 may continue DL communications (i.e., receiving control signals, reference signals, DL PDUs, etc.) with the S-MN 104 and / or transmit control signals (e.g., HARQ ACKs, HARQ NAKs, and / or channel state information) to the S-MN 104 on the PUCCH until event 332A occurs or the DAPS release timer at the UE 102 expires. In some embodiments, the T-MN 106B may configure a timer value for the DAPS release timer in the handover command message in event 314A or in the RRC reconfiguration message in event 332A. Upon receiving 318A the handover command message or receiving 332A the RRC reconfiguration message, the UE 102 starts the DAPS release timer. When the DAPS release timer expires, the UE 102 stops (336A) communicating with the S-MN 104. In other embodiments, if the T-MN 106B does not include a timer value in the handover command message or the RRC reconfiguration message, the UE 102 uses a predetermined timer value. The T-MN 106B may include a predetermined timer value in the handover success message, which may be the same as the timer value in the RRC reconfiguration message, or greater than the timer value in the handover command message.

[0072] In some embodiments, the T-MN configuration includes multiple configuration parameters (e.g., corresponding to physical layer, MAC layer, and / or RLC layer configuration) to configure radio resources. The UE 102 may use these multiple configuration parameters to communicate with the T-MN 106B via the target PCell 126B. The multiple configuration parameters may configure zero, one, or more radio bearers, including SRBs (e.g., SRB1, SRB2, and / or SRB4) and / or DRBs. For example, the UE 102 may exchange RRC messages with the T-MN 106B via an SRB (i.e., an SRB of the target PCell), and communicate data with the T-MN 106B via a DRB.

[0073] In some embodiments, the MN configuration (i.e., S-MN configuration or T-MN configuration) may include a CellGroupConfig IE. The MN configuration may be an RRCReconfiguration message, an RRCReconfiguration-IE, or a CellGroupConfig IE in accordance with 3GPP TS 38.331, or an RRCConnectionReconfiguration message or an RRCConnectionReconfiguration-IE in accordance with 3GPP TS 36.331. In some embodiments, the MN configuration may include configurations in a CellGroupConfig IE, an RRCReconfiguration-IE, or an RRCConnectionReconfiguration-IE.

[0074] In some embodiments, Figure 1B As shown, the S-MN 104 is composed of a CU 172 and one or more DUs 174. The DU 174 may generate an S-MN configuration or at least a portion of the S-MN configuration, and send the S-MN configuration (or a portion) to the CU 172. If the DU 174 generates only a portion of the S-MN configuration, the CU 172 may generate the remaining portion of the S-MN configuration. In one embodiment, the DU 174 may communicate with the UE 102 via a portion of the S-MN configuration, and the CU 172 may communicate with the UE 102 via the remaining portion of the S-MN configuration. For example, the S-MN configuration (or a portion) generated by the DU 174 may include one or more random access configurations, physical downlink control channel (PDCCH) configurations, PUCCH configurations, etc. The remaining portion of the S-MN configuration generated by the CU 172 may include an SRB configuration, a DRB configuration, a security configuration, and / or a measurement configuration. In other embodiments, the DU 174 may include a cell group configuration (eg, CellGroupConfig IE) in the S-MN configuration, and the CU 172 may include a radio bearer configuration (RadioBearerConfig IE) in the S-MN configuration.

[0075] Similarly, in some embodiments, Figure 1BAs shown, T-MN 106B consists of CU 172 and one or more DUs 174. UE 102 may employ at least one of DUs 174 to perform (322A) a random access procedure. DU 174 generates some configurations (e.g., one or more random access configurations, PDCCH configurations, PUCCH configurations) and sends these configurations to CU 172. CU 172 may include other configurations (e.g., SRB configurations, DRB configurations, security configurations, and / or measurement configurations) in the handover command message. In other embodiments, DU 174 may generate a cell group configuration (e.g., CellGroupConfig IE) and send the cell group configuration to CU 172, which in turn may include a radio bearer configuration (e.g., RadioBearerConfig IE) and a cell group configuration in the handover command message.

[0076] In some implementations, if the S-MN 104 is a gNB, the handover command message may be an RRCReconfiguration message, the handover completion message may be an RRCReconfigurationComplete message, and the RRC reconfiguration message and the RRC reconfiguration completion message may be an RRCReconfiguration message and an RRCReconfigurationComplete message, respectively.

[0077] In some implementations, if the S-MN 104 is an eNB or an ng-eNB, the handover command message may be an RRCConnectionReconfiguration message, the handover completion message may be an RRCConnectionReconfigurationComplete message, and the RRC reconfiguration message and the RRC reconfiguration completion message may be an RRCConnectionReconfiguration message and an RRCConnectionReconfigurationComplete message, respectively.

[0078] Now go to Figure 3B , according to DAPS switching scenario 300B, similar to Figure 3A In the DAPS handover scenario 300A, base station 104 operates as an S-MN for UE 102 and base station 106B operates as a T-MN for UE 102. Figure 3A In FIG. 1 , UE 102 successfully performs DAPS handover to T-MN 106B before stopping and releasing the power coordination configuration, but Figure 3B , UE 102 fails to successfully perform DAPS handover.

[0079] Initially, similar to event 302A, UE 102 communicates (302B) data with S-MN 104 using the S-MN configuration. Later, S-MN 104 determines (304B) to initiate a DAPS handover for T-MN 106B and UE 102 to communicate, similar to event 304A.

[0080] Similar to events 312A, 314A, 316A, and 318A, respectively, after determining (304B) to initiate a DAPS handover, the S-MN 104 sends 312B a handover request message to the T-MN 106B, the T-MN 106B generates (314B) a handover command message for DAPS handover, the handover command message including the T-MN configuration including the DAPS power coordination configuration, the T-MN 106B sends 316B the handover command message to the S-MN 104 in a handover request confirm message, and the S-MN 104 transmits 318B the handover command message to the UE 102.

[0081] Similar to events 352A and 320A, respectively, in response to receiving 318B the handover command message, UE 102 applies (352B) the DAPS power coordination configuration and continues (320B) to communicate with S-MN 104 using the S-MN configuration while UE 102 attempts to handover to T-MN 106B in accordance with the handover command message.

[0082] After UE 102 applies (352B) the DAPS power coordination configuration or continues (320B) to communicate with S-MN 104, UE 102 determines (321B) that the DAPS handover has failed, i.e., UE 102 has failed (e.g., within a certain duration) to perform a DAPS handover to T-MN 106B using a random access procedure similar to 322A. In response to the determination at event 321B, UE 102 stops 354B applying the DAPS power coordination configuration and releases the DAPS power coordination configuration. In some embodiments, RRC controller 152 may send an indication to PHY 202 of UE 102 to cause PHY 202 to stop applying the DAPS power coordination configuration. In some embodiments, in response to the determination at event 321B, UE 102 releases the T-MN configuration received in event 318B.

[0083] If the radio link between the UE 102 and the S-MN 104 is available (i.e., no radio link failure occurs on the radio link between the UE 102 and the S-MN 104), the UE 102 may transmit 342B to the S-MN 104, for example, via SRB1, a failure information message (e.g., FailureInformation) indicating a DAPS handover failure with respect to the T-MN 106B. In some embodiments, the UE 102 may then perform (348B) an RRC re-establishment procedure with the T-MN 106B on the cell 126B or another cell. If the radio link between the UE 102 and the S-MN 104 is not available, the UE 102 does not transmit a failure information message to the S-MN 104. To perform the RRC re-establishment procedure, the UE 102 transmits an RRC re-establishment request message to the T-MN 106B, which in turn transmits an RRC re-establishment message to the UE 102. In response to the RRC re-establishment message, UE 102 may transmit an RRC re-establishment complete message to T-MN 106B.

[0084] Because the UE 102 has stopped 354B applying the DAPS power coordination configuration and released the DAPS power coordination configuration, the UE 102 advantageously does not unnecessarily limit its maximum uplink power according to the DAPS power coordination configuration (e.g., CP1 and / or CP2) when communicating with the S-MN 104, such as when transmitting 342B a failure information message to the S-MNB 104, and / or when communicating with the T-MN 106B, such as during or after performing (348B) an RRC re-establishment procedure with the T-MN 106B.

[0085] In some embodiments, the T-MN 106B may release (356B) the DAPS power coordination configuration at some time after generating or transmitting the handover command message to the S-MN 104. In some embodiments, the T-MN 106B may release the DAPS power coordination configuration if the UE 102 does not successfully handover to the T-MN 106B within a period of time. In other embodiments, the T-MN 106B may release the DAPS power coordination configuration in response to an RRC re-establishment procedure.

[0086] In some implementations, UE 102 may perform an RRC re-establishment procedure with S-MN 104 instead of T-MN 106B via cell 122 or cell 124. Therefore, because UE 102 has stopped (354B) applying the DAPS power coordination configuration and released the DAPS power coordination configuration, UE 102 is also not restricted by DAPS power coordination configuration parameter CP1 during and after performing the RRC re-establishment procedure with S-MN 104.

[0087] In some implementations, if the T-MN 104 is a gNB, the RRC reestablishment request message, the RRC reestablishment message, and the RRC reestablishment complete message may be an RRCReestablishmentRequet message, an RRCReestablishment message, and an RRCReestablishmentComplete message, respectively. If the T-MN 106B is an eNB or an ng-eNB, the RRC reestablishment request message, the RRC reestablishment message, and the RRC reestablishment complete message may be an RRCConnectionReestablishmentRequest message, an RRCConnectionReestablishment message, and an RRCConnectionReestablishmentComplete message, respectively.

[0088] although Figure 3A and Figure 3B The DAPS handover scenarios 300A and 300B are depicted as occurring between two base stations (e.g., base stations 104, 106B) relative to the UE 102, but in some embodiments, the DAPS handover scenarios 300A and 300B may be performed within a single base station (e.g., S-MN 104) relative to the UE 102. In such a scenario, the messages exchanged between the S-MN 104 and the T-MN 106B (e.g., events 312A, 312B, 316A, 316B, 328A) may be omitted, and the events performed or otherwise involving the T-MN 106B (e.g., events 314A, 314B, 322A, 324A, 326A, 332A, 356A, 356B, 334A, 348B) may be performed or otherwise involving the S-MN 104.

[0089] Reference now Figure 4A According to the DAPS PSCell change scenario 400A, the base station 104 operates as the MN for the UE 102, the base station 106A operates as the S-SN for the UE 102, and the base station 106B operates as the T-SN for the UE 102.

[0090] Initially, the UE 102 in DC communicates (402A) data with the MN 104 via the PCell 124 by using the MN configuration, and communicates (402A) data with the S-SN 106A via the PSCell 126A by using the S-SN configuration.

[0091] Later, either blindly or in response to detecting an appropriate event (similar to Figure 3A ), or in response to an SN Change Required message received from S-SN 106A, MN 104 determines (404A) to initiate a DAPS PSCell change involving an SN change (i.e., a MN-initiated DAPS SN addition or change procedure) for T-SN 106B and UE 102 to communicate via T-PSCell 126B.

[0092] In response to the determination at event 404A, MN 104 sends 412A an SN Addition Request message to T-SN 106B. In response, T-SN 106B generates (414A) a T-SN configuration for the DAPS PSCell change and sends 416A the T-SN configuration in an SN Addition Request Acknowledge message to MN 104. In other embodiments, in response to the determination at event 404A, MN 104 may send an SN Release Request message (or alternatively, an SN Modification Request message) to S-SN 106A to request S-SN 106A to perform a DAPS PSCell change or continue to communicate with UE 102, respectively. S-SN 106A may then send an SN Release Request Acknowledge message or an SN Modification Request Acknowledge message to MN 104 in response to the SN Release Request message or the SN Modification Request message, respectively. In other embodiments, MN 104 may not send an SN Release Request message (or alternatively, an SN Modification Request message) to S-SN 106A, allowing S-SN 106A to continue communicating with UE 102, because S-SN 106A is unaware of the DAPS SN change and therefore behaves as usual. In still other embodiments, if MN 104 makes a determination at event 404A in response to the SN Change Required message, MN 104 may send an SN Change Acknowledge message to S-SN 106A to request S-SN 106A to perform a DAPS PSCell change or continue communicating with UE 102.

[0093] In response to receiving 416A the T-SN configuration from the T-SN 106B, the MN 104 generates a DAPS power coordination and includes both the T-SN configuration and the DAPS power coordination configuration in an RRC container message, and transmits 417A the RRC container message to the UE 102. In response to receiving 417A the DAPS power coordination configuration, the UE 102 applies (452A) the DAPS power coordination configuration. In some embodiments, the RRC controller 152 may send the DAPS power coordination configuration parameters to the PHY 202 of the UE 102 in the DAPS power coordination configuration, and the PHY in turn applies the DAPS power coordination configuration parameters. In response to receiving 417A the RRC container message, the UE 102 also transmits 418A an RRC container response message including an RRC reconfiguration complete message to the MN 104. In some implementations, in response to the RRC container response message, the MN 104 may send 419A an SN Reconfiguration Complete message to the T-SN 106B. Events 404A, 412A, 414A, 416A, 417A, 452A, 418A, and 419A may be performed in Figure 4A Collectively referred to as DAPS PSCell change preparation process 460A.

[0094] In some embodiments, the MN 104 receives the DAPS power coordination configuration from the T-SN 106B in the SN Add Request Confirm message instead of generating the DAPS power coordination configuration at event 417A. In one such embodiment, the T-SN 106B may generate the DAPS power coordination configuration (e.g., DAPS-PowerCoordinationInfo-r16 IE or DAPS-Configuration-r16 IE) and include it in the T-SN Configuration or SN Add Request Confirm message. In other embodiments, the S-SN 106A may generate the DAPS power coordination configuration and send it to the MN 104 in the SN Change Required message or the SN Modify Request Confirm message.

[0095] In some embodiments, the T-SN 106B may send a DAPS PSCell change configuration (e.g., daps-Config field) to the MN 104 in the SN Add Request Ack message or in the T-SN configuration, indicating that the particular DRB is a DAPS bearer, which in turn may include the DAPS PSCell change configuration in the RRC container message. The DAPS PSCell change configuration enables the UE 102 to communicate with the S-SN 106A (using the S-SN configuration) and the T-SN 106B (during and after a successful DAPS PSCell change) using DAPS for DAPS bearers (e.g., DAPS 200). Thus, in response to receiving 417 the RRC container message, the UE 102 and the S-SN 106A continue (420A) to communicate with each other (i.e., with the MN 104 in DC) using the S-SN configuration, while the UE 102 attempts to perform a DAPS PSCell change to the T-SN 106B via the T-PSCell 126B according to the T-SN configuration.

[0096] In attempting to perform a DAPS PSCell change, the UE 102 initiates 422A a random access procedure with the T-SN 106B via the T-PSCell 126B, e.g., by using one or more random access configurations in the T-SN configuration. After the T-SN 106B identifies the UE 102 during the random access procedure (e.g., the UE 102 successfully resolves contention), the UE 102 communicates 426A in DC with the MN 104 via the PCell 124 and with the T-SN 106B via the T-PSCell 126B, while continuing to communicate with the S-SN 106A via the PSCell 126A, using the configurations in the T-SN configuration.

[0097] After receiving 418A the RRC container response message, the MN 104 may send 428A a UE Context Release message to the S-SN 106A. In response to or after receiving the UE Context Release message, the S-SN 106A stops (430A) communicating with the UE 102. Alternatively, if the S-SN 106A does not receive DL data packets from the CN 110 (e.g., the S-GW 112 or the UPF 162), the S-SN 106A stops (430A) communicating with the UE 102.

[0098] The DAPS PSCell change configuration and / or the DAPS power coordination configuration enables the UE 102 to continue to communicate with the S-SN 106A while communicating with the T-SN 106B. Since the UE 102 no longer needs to use DAPS to continue to communicate with the S-SN 106A after successfully performing the DAPS PSCell change, the UE 102 can stop (454A) applying the DAPS power coordination configuration and release the DAPS power coordination configuration. In this way, when communicating with the T-SN 106B, the UE 102 will not unnecessarily limit its maximum uplink power according to the DAPS power coordination configuration, thereby reducing the risk of radio link failure with the T-SN 106B. In some embodiments, the T-SN 106B can transmit 432A an RRC reconfiguration message including a DAPS release indicator to the UE 102, for example, via an SRB (e.g., SRB3) between the UE 102 and the T-SN 106B or via the MN 104. In response to the RRC reconfiguration message, the UE 102 may stop (454A) applying the DAPS power coordination configuration and release the DAPS power coordination configuration. In some implementations, the RRC controller 152 may send an indication to the PHY 202 of the UE 102 to cause the PHY 202 to stop applying (454A) the power coordination configuration.

[0099] In some implementations, the T-SN 106B may also release (456A) the DAPS power coordination configuration because the UE 102 no longer needs to use the DAPS power coordination configuration and / or the DAPS power coordination configuration is released by the UE 102. That is, after event 414A of including the DAPS power coordination configuration in the T-SN configuration, the T-SN 106B may release the DAPS power coordination configuration.

[0100] After event 454A, UE 102 may send 434A an RRC reconfiguration complete message to T-SN 106B via an SRB (e.g., SRB3) between UE 102 and T-SN 106B or via MN 104, and cease (436A) communication with S-SN 106A. In some implementations, in response to the DAPS release indicator, an RF chip, receiver, or transceiver of UE 102 used to communicate with S-SN 106A during the DAPS PSCell change may enter a low power mode, a sleep mode, or shut down completely if the DAPS PSCell change is an inter-frequency DAPS PSCell change.

[0101] In some embodiments, the DAPS power coordination configuration includes one or more of the following DAPS power coordination configuration parameters: a maximum total transmission power (or its value) that the UE 102 can use for uplink communications with the S-SN 106A during a DAPS PSCell change (interchangeably referred to as "CP4"), a maximum total transmission power (or its value) that the UE 102 can use for uplink communications with the T-SN 106B during a DAPS PSCell change (interchangeably referred to as "CP5"), and / or an uplink power sharing mode used by the UE 102 during a DAPS PSCell (interchangeably referred to as "CP6"). In some embodiments, the DAPS power coordination configuration parameters can be included in a field or IE of the DAPS power coordination configuration.

[0102] After UE 102 (e.g., PHY 202) applies the DAPS power coordination configuration during the DAPS PSCell change, UE 102 (e.g., PHY 202) may determine (or manage or coordinate) its uplink transmission power for transmission to S-SN 106A and its uplink transmission power for transmission to T-SN 106B according to the DAPS power coordination configuration (e.g., according to 3GPP specification 38.331 v16.1.0 or 36.331 v16.1.0). In some embodiments, if the uplink power sharing mode specified in CP6 is the first mode (e.g., semi-static mode 1), UE 102 manages its uplink transmission power to not exceed CP4 when transmitting (420A) to S-SN 106A and not exceed CP5 when transmitting (426A) to T-SN 106B. In other embodiments, if the uplink power sharing mode is the second mode (e.g., semi-static mode 2 or dynamic mode), and the first uplink transmission to the S-SN 106A partially or completely overlaps with the second uplink transmission to the T-SN 106B, the UE 102 manages the uplink transmission powers of the first uplink transmission and the second uplink transmission so as not to exceed CP4 and CP5, respectively. If the uplink power sharing mode is the second mode, and the first uplink transmission to the S-SN 106A does not overlap with the second uplink transmission to the T-MN 106B, the UE 102 manages the uplink transmission powers of the first uplink transmission and the second uplink transmission so as not to exceed corresponding maximum total transmission power values ​​other than those included in the DAPS power coordination configuration.

[0103] In some embodiments, the S-SN 106A and the T-SN 106B may provide these respective maximum total transmit power values ​​to the UE 102 in the respective non-DAPS configurations via SRB 3 or via the MN 104. In some embodiments, the S-SN 106A may send the non-DAPS configuration to the UE 102 in a dedicated message (e.g., an RRC reconfiguration message), and the T-SN 106B may send the non-DAPS configuration to the UE 102 in a dedicated message (e.g., an RRC reconfiguration message). In other embodiments, the MN 104 may provide the maximum total transmit power values ​​directly to the UE 102 in the non-DAPS configuration in a dedicated message (e.g., an RRC reconfiguration message).

[0104] In some embodiments, the T-SN 106B receives configuration restrictions for DAPS PSCell changes from the MN 104 in an SN add request message. The T-SN 106B may generate a DAPS power coordination configuration according to the configuration restrictions. In one embodiment, the MN 104 may generate preferred power coordination configuration parameters and include them in the configuration restrictions. In another embodiment, the MN 104 may receive preferred power coordination configuration parameters from the S-SN 106A and include them in the configuration restrictions. In any event, the T-SN 106B may include such preferred parameters in the DAPS power coordination configuration. In one embodiment, the MN 104 or the S-SN 106A may determine the preferred parameters based on the UE capabilities of the UE 102. For example, the UE capabilities may indicate or include the UE power class and / or DAPS power sharing mode supported by the UE 102. If the UE capabilities include or otherwise indicate the supported uplink power sharing mode, the MN 104 may set the preferred uplink sharing mode to one of the supported uplink power sharing modes. If UE 102 is configured to implement all uplink sharing modes supported by RAN 105, MN 104 or S-SN 106A may implement the uplink sharing modes supported by RAN 105 according to the above reference. Figure 3A At least one of the described PCP1 and / or PCP2 parameters is used to select a specific preferred uplink sharing mode.

[0105] Similarly, in another embodiment, MN 104 or T-SN 106B may determine some or all of the DAPS power coordination configuration parameters in the DAPS power coordination configuration based on the preferred power coordination configuration parameters and / or the UE capabilities of UE 102. If the UE capabilities include or otherwise indicate a supported uplink power sharing mode, MN 104 or T-SN 106B may set the uplink sharing mode to one of the supported uplink power sharing modes or the preferred uplink sharing mode provided by MN 104 or S-SN 106A. If UE 102 is configured to implement all uplink sharing modes supported by RAN 105, T-SN 106B may select a specific uplink sharing mode based on PCP1, PCP2, and / or the same preferred power coordination configuration parameters provided by MN 104 or S-SN 106A.

[0106] In some embodiments, after successfully completing (422A) the random access procedure, UE 102 may begin transmitting UL data PDUs to T-SN 106B via cell 126B, stop transmitting and retransmitting UL data PDUs to S-SN 106A, stop transmitting control signals to S-SN 106A on the PUCCH, stop transmitting new UL data PDUs to S-SN 106A while continuing to retransmit UL data PDUs to S-SN 106A, continue DL communications with S-SN 106A, and / or keep transmitting control signals to S-SN 106A until event 432A occurs or a DAPS release timer at UE 102 expires, as described above with reference to FIG. Figure 3A As described. In some embodiments, the T-SN 106B may configure a timer value for the DAPS release timer in an RRC reconfiguration message or in a T-SN configuration. In other embodiments, the MN 104 configures a timer value for the DAPS release timer in an RRC container message. Upon receiving the timer value, the UE 102 starts a DAPS release timer to count the timer value. When the DAPS release timer expires, the UE 102 stops (436A) communicating with the S-SN 106A. In other embodiments, if the MN 104 or T-SN 106B does not provide a timer value to the UE 102, the UE 102 uses a predetermined timer value.

[0107] In some embodiments, T-SN 106B includes multiple configuration parameters in the T-SN configuration to configure radio resources for UE 102 to communicate with T-SN 106B via T-PSCell 126B. Multiple configuration parameters can configure the physical layer, the media access control (MAC) layer, and the radio link control bearer. The DAPS PSCell change configuration can be associated with a radio bearer (e.g., a DRB) or specific to a radio bearer. For example, at event 416A, T-SN 106B can include the DAPS PSCell change configuration in the RB configuration (e.g., RadioBearerConfig IE, DRB-ToAddModList IE, or DRB-ToAddMod IE) in the SN add request confirmation message; and at event 417A, MN 104 can include the RB configuration in the RRC container message. S-SN 106A can also configure a specific DRB and transmit the RB configuration configuring the specific DRB to UE 102.

[0108] In some implementations, T-SN 106B may not configure the SCell for UE 102 in the T-SN configuration. T-SN 106B may later transmit an RRC reconfiguration message to UE 102 to configure the SCell of T-SN 106B. In response, UE 102 may transmit an RRC reconfiguration complete message to T-SN 106B via T-PSCell 126B or the SCell configured for each in the RRC reconfiguration message.

[0109] In some embodiments, the SN configuration (i.e., S-SN configuration or T-SN configuration) may include a CellGroupConfig IE. The SN configuration may be an RRCReconfiguration message, an RRCReconfiguration-IE, or a CellGroupConfig IE in accordance with 3GPP TS 38.331, or an RRCConnectionReconfiguration message or an RRCConnectionReconfiguration-IE in accordance with 3GPP TS 36.331. In some embodiments, the MN configuration may include configurations in a CellGroupConfig IE, an RRCReconfiguration-IE, or an RRCConnectionReconfiguration-IE.

[0110] If the S-SN 106A is a gNB, the T-SN configuration or RRC reconfiguration message may be an RRCReconfiguration message, and the RRC reconfiguration complete message may be an RRCReconfigurationComplete message defined in 3GPP TS 38.331. If the S-SN 106A is an ng-eNB, the T-SN configuration or RRC reconfiguration message may be an RRC connection RRCConnectionReconfiguration message, and the RRC reconfiguration complete message may be an RRCConnectionReconfigurationComplete message defined in 3GPP TS 36.331.

[0111] Now go to Figure 4B According to DAPS PSCell change scenario 400B, base station 104 operates as a MN for UE 102, base station 106A operates as an S-SN, and base station 106B operates as a T-SN for UE 102, similar to Figure 4A The DAPSP Cell changes to 400A. Figure 4A In FIG. 1 , UE 102 successfully performs a DAPS PSCell change to T-SN 106B before stopping and releasing the power coordination configuration, but Figure 4B , UE 102 fails to successfully perform DAPS PSCell change.

[0112] Initially, similar to event 402A, UE 102 in DC communicates (402B) data with MN 104 via PCell 124 by using the MN configuration, and with S-SN 106A via PSCell 126A by using the S-SN configuration.

[0113] Later, similar to event 460A, MN 104, S-SN 106A and T-SN 106B jointly perform (460B) a DAP SSCell change preparation procedure. Similar to event 420A, using the S-SN configuration, UE 102 and S-SN 106A continue 420B to communicate with each other (i.e., communicate with MN 104 in DC), while UE 102 attempts to perform a DAPS PSCell change to T-SN 106B via T-PSCell 126B according to the T-SN configuration received in event 460B.

[0114] After UE 102 applies the DAPS power coordination configuration during the SN change process in event 460B, or continues (420B) to communicate with S-SN 106A by using the S-SN configuration, UE 102 determines (421B) that the DAPS PSCell change failed, that is, UE 102 failed to perform the DAPS PSCell change to T-SN 106B (e.g., within a specific duration). In response to the determination at event 421B, UE 102 stops (454B) applying the DAPS power coordination configuration and releases the DAPS power coordination configuration. In some embodiments, RRC controller 152 can send an indication to PHY 202 of UE 102 to cause PHY 202 to stop applying the DAPS power coordination configuration. In some embodiments, in response to the determination at event 421B, UE 102 releases the T-SN configuration received in event 460B.

[0115] If the radio link between UE 102 and S-SN 106A is available (i.e., no radio link failure occurs on the radio link between UE 102 and S-SN 106A), and the SRB (e.g., SRB3) between UE 102 and S-SN 106A is not available, UE 102 may transmit a failure information message (e.g., FailureInformation) to MN 104 via SRB (e.g., SRB1), for example, at time 452B, or transmit an SCG failure information message (e.g., SCGFailureINformation) indicating a DAPSPSCell change failure with respect to T-SN 106B at event 472B. In one embodiment, after receiving 452B the failure information message from UE 102 in an RRC container message (e.g., ULInformationTransferMRDC), MN 104 extracts the failure information message from the RRC container message and sends 453B the failure information message to S-SN 106A in an RRC transfer (RRC Transfer) message. In another embodiment, MN 104 does not send a failure information message to S-SN 106A.

[0116] If the radio link between UE 102 and S-SN 106A is available, and the SRB (e.g., SRB3) between UE 102 and S-SN 106A is available, then at event 455B, UE 102 may transmit a failure information message indicating a DAPS PSCell change failure relative to T-SN 106B to S-SN 106A via the available SRB. In response, S-SN 106A may send an SN message (e.g., an SN modification required message) to MN 104 to notify MN 104 of the DAPS PS cell change failure.

[0117] If the radio link between UE 102 and S-SN 106A is unavailable, UE 102 may transmit 472B an SCG Failure Information message to MN 104 to inform MN 104 of the DAPS PSCell change failure.

[0118] Because UE 102 has stopped (454B) applying the DAPS power coordination configuration and released the DAPS power coordination configuration, UE 102 advantageously will not unnecessarily limit its maximum uplink power according to the DAPS power coordination configuration when communicating with MN 104, such as when transmitting a failure information message or an SCG failure information message, and / or when communicating with S-SN 106A, such as when transmitting a failure information message.

[0119] In some embodiments, the T-SN 106B may release (456B) the DAPS power coordination configuration after generating the T-SN configuration or transmitting the T-SN configuration to the MN 104. In some embodiments, the T-SN 106B may release the DAPS power coordination configuration if the UE 102 does not successfully perform a DAPS PSCell change to the T-SN 106B within a period of time. In other embodiments, the MN 104 may release the DAPS power coordination configuration in response to receiving 452B a failure information message, or in response to receiving an SN message from the S-SN 106A notifying that the DAPS PSCell change failed.

[0120] although Figure 4A and Figure 4BThe DAPS PSCell change scenarios 400A and 400B are depicted as occurring between two SNs (e.g., base stations 106A, 106B) relative to the UE 102, but in some embodiments, the DAPS PSCell change scenarios 400A and 400B may be performed within a single SN (e.g., S-SN 106A) relative to the UE 102. In such a scenario, messages exchanged between the MN 104 and the T-SN 106B (e.g., events 412A, 416A, 419A) may be omitted, and events (e.g., 414A, 419A, 422A, 426A, 432A, 456A, 434A, 460B) involving the S-SN 106A may be performed or otherwise.

[0121] Figure 5A is a flow chart depicting an example method 500A implemented in a user equipment (e.g., UE 102) for applying and later releasing a DAPS power coordination configuration when switching from a source base station (e.g., S-MN 104, S-SN 106A) to a target base station (e.g., T-MN 106B, T-SN 106B).

[0122] At block 502A, the user equipment receives a first message from a source base station, the first message including a DAPS power coordination configuration for DAPS operation with the source base station and the target station (e.g., in any of events 318A, 417A). According to the DAPS operation, the user equipment (e.g., via DAPS 200) may perform a DAPS handover or a DAPS PSCell change. In some embodiments, the first message may be a handover command message or an RRC container message.

[0123] At block 504A, the user equipment applies the DAPS power coordination configuration to communicate with the source base station and the target base station (e.g., in either of events 352A, 452A). According to the DAPS power coordination configuration, the user equipment limits the respective maximum total transmission uplink powers when communicating with the source base station and the target base station.

[0124] At block 506A, the user equipment receives a second message from the target base station indicating release of DAPS operation (e.g., in any of events 332A, 432A). Thus, the target base station explicitly provides the second message to the user equipment to indicate that the user equipment should stop communicating with the source base station and continue communicating with the target base station. In some embodiments, the second message may be an RRC reconfiguration message.

[0125] In block 508A, in response to receiving the second message, the user equipment disconnects from the source base station (i.e., stops communicating with the source base station), stops applying the DAPS power coordination configuration, and releases the DAPS power coordination configuration (e.g., in any of events 336A, 354A, 436A, 454A). When the DAPS power coordination configuration is released, when communicating with the target base station after successfully performing a DAPS handover or a DAPS PSCell change, the user equipment will not continue to limit its maximum uplink power according to the DAPS power coordination configuration. Because the DAPS power limitation has been removed, the user equipment can increase its uplink power to its maximum uplink power, and the user equipment can reduce the chance of a radio link failure with the target base station.

[0126] Figure 5B 1 is a flow chart depicting another example method 500B implemented in a user equipment (e.g., UE 102) for applying and later releasing a DAPS power coordination configuration when switching from a source base station (e.g., S-MN 104, S-SN 106A) to a target station (e.g., T-MN 106B, T-SN 106B). Figure 5A In the embodiment, the user equipment releases the DAPS power coordination configuration in response to an explicit message (e.g., an RRC reconfiguration message) from the target base station, but in Figure 5B In the embodiment, UE 102 releases the DAPS power coordination configuration after performing a random access procedure with the target base station.

[0127] At block 502B, similar to block 502A, the user equipment receives a first message from a source base station, the first message including a DAPS power coordination configuration for DAPS operation with the source base station and a target station (eg, in any of events 318A, 417A).

[0128] At block 504B, similar to block 504A, the user equipment applies the DAPS power coordination configuration to communicate with the source base station and the target base station (eg, in any of events 352A, 452A).

[0129] At block 506B, in response to the first message, the user equipment performs a random access procedure with the target base station (eg, in any of events 322A, 422A).

[0130] At block 508B, after performing the random access procedure, the user equipment stops applying the DAPS power coordination configuration and releases the DAPS power coordination configuration (eg, in any of events 354A, 454A).

[0131] At block 510B, similar to block 506A, the user equipment receives a second message (eg, event 332A or 432A) indicating release of DAPS operation.

[0132] At block 512B, the user equipment disconnects from the source base station (ie, stops communicating with the source base station) in response to the second message, thereby successfully performing the DAPS operation (eg, in any of events 336A, 436A).

[0133] Figure 5C 1 is a flow chart depicting another example method 500C implemented in a user equipment (e.g., UE 102) for applying and releasing a DAPS power coordination configuration when switching from a source base station (e.g., S-MN 104, S-SN 106A) to a target station (e.g., T-MN 106B, T-SN 106B). Figure 5A and Figure 5B In the example, the user equipment successfully performs a DAPS handover or a DAPS PSCell change to the target base station, but Figure 5C In the example, the user equipment fails to successfully perform DAPS handover or DAPS PSCell change.

[0134] At block 502C, similar to blocks 502A and 502B, the user equipment receives a first message from a source base station including a DAPS power coordination configuration for DAPS operation with the source base station and a target station (eg, in any of events 318B, 460B).

[0135] At block 504C, similar to blocks 504A and 504B, the user equipment applies the DAPS power coordination configuration to communicate with the source base station and the target base station (eg, in any of events 352B, 460B).

[0136] At block 506C, the user equipment determines a failure (eg, radio link failure) when performing DAPS operation (eg, in any of events 321B, 421B). That is, the user equipment fails to perform a DAPS handover or DAPS PSCell change to a target base station.

[0137] In response to determining the failure, at block 508C, the user equipment stops applying the DAPS power coordination configuration and releases the DAPS power coordination configuration (e.g., in any of events 354B, 454B). In this manner, for example, if the user equipment later performs an RRC re-establishment procedure with the source base station or the target source base station, the user equipment is not limited by the maximum uplink power specified in the DAPS power coordination configuration during and after performing the RRC re-establishment procedure with the source base station or the target base station. Because the user equipment can increase its uplink power to exceed the maximum uplink power indicated in the DAPS power coordination configuration, the user equipment can reduce the chance of a radio link failure with the source base station or the target base station.

[0138] Figure 6 is a flow chart depicting an example method 600 implemented in a RAN (e.g., RAN 105) for providing a reference Figure 5A , Figure 5B and Figure 5C A user equipment (eg, UE 102) is described that provides a DAPS power coordination configuration and later releases the DAPS power coordination configuration.

[0139] At block 602, the RAN transmits a first message to a user equipment, the first message including a DAPS power coordination configuration for DAPS operation with a source base station and a target base station of the RAN (e.g., in any of events 318A, 318B, 417A, 460B). According to the DAPS operation, the user equipment (e.g., via DAPS 200) may perform a DAPS handover or a DAPS PSCell change. In some embodiments, the first message may be a handover command message or an RRC container message. The first message may also include a plurality of configuration parameters for configuring radio resources, so that the user equipment may communicate with the RAN using these plurality of configuration parameters during and after successful execution of the DAPS handover or the DAPS PSCell change.

[0140] At block 604, after transmitting the first message, the RAN releases the DAPS power coordination configuration (e.g., in any of events 356A, 356B, 456A, 456B). In some embodiments, the RAN releases the DAPS power coordination configuration (e.g., in any of events 332A, 432A) after transmitting the first message and the second message (e.g., an RRC reconfiguration message) to the user equipment to request the user equipment to disconnect from the source base station. In another embodiment, the RAN releases the DAPS power coordination configuration (e.g., in event 342B) after transmitting the first message to the user equipment and after receiving a third message (e.g., a failure information message) from the user equipment. In some embodiments, the RAN may retain a plurality of configuration parameters provided to the user equipment in the first message.

[0141] Next, Fig. 7A An example method 700A is shown for managing power coordination configuration while performing DAPS procedures, which may be implemented in a suitable UE, such as UE 102 .

[0142] At block 702A, the UE receives a power coordination configuration from the RAN for the UE to apply to constrain uplink power when communicating with a source cell and a target cell of the RAN (eg, events 318A, 318B, 460A, 460B).

[0143] At block 704A, the UE initiates a DAPS procedure according to the power coordination configuration (eg, events 320A, 320B, 420A, 420B).

[0144] At block 706A, in response to detecting the triggering condition, the UE releases the power coordination configuration (e.g., events 354A, 354B, 454A, 454B). In some embodiments, the UE releases the power coordination configuration when the UE is connected to the target cell while performing the DAPS procedure. In other embodiments, the UE releases the power coordination configuration when the UE receives an indication from the RAN via the target cell that the UE is to release the power coordination configuration. In yet other embodiments, the UE releases the power coordination configuration when the UE fails to connect to the target cell while performing the DAPS procedure.

[0145] Next, Figure 7B An example method 700B is shown for managing power coordination configuration when performing a DAPS procedure with a UE (eg, UE 102), which may be implemented in a suitable RAN such as RAN 105.

[0146] At block 702B, the RAN determines that the UE will perform a DAPS procedure according to the power coordination configuration to connect to the target cell and disconnect from the source cell after connecting to the target cell (eg, events 304A, 304B, 460A, 460B).

[0147] At block 704B, the RAN transmits a power coordination configuration to the UE for the UE to apply to constrain uplink power when communicating with the source cell and the target cell (eg, events 318A, 318B, 460A, 460B).

[0148] At block 706B, in response to detecting the trigger condition, the RAN causes the UE to release the power coordination configuration (e.g., events 332A, 332B, 432A, 432B). In some embodiments, the RAN causes the UE to release the power coordination configuration when the RAN determines that the UE is connected to the RAN via the target cell after performing the DAPS procedure. In other embodiments, the RAN causes the UE to release the power coordination configuration when the RAN transmits an indication to the UE via the target cell that the UE is to release the power coordination configuration.

[0149] The following description can be applied to the above description.

[0150] The user equipment (e.g., UE 102) in which the technology of the present disclosure can be implemented can be any suitable device capable of wireless communication, such as a smart phone, a tablet computer, a laptop computer, a mobile game console, a point of sale (POS) terminal, a health monitoring device, a drone, a camera, a media streaming dongle or another personal media device, a wearable device such as a smart watch, a wireless hotspot, a femtocell base station, or a broadband router. In addition, in some cases, the user equipment can be embedded in an electronic system, such as a head unit or an advanced driver assistance system (ADAS) of a vehicle. In addition, the user equipment can be operated as an Internet of Things (IoT) device or a mobile Internet device (MID). Depending on the type, the user equipment may include one or more general-purpose processors, a computer-readable memory, a user interface, one or more network interfaces, one or more sensors, etc.

[0151] Certain embodiments are described in the present disclosure as including logic or multiple components or modules. A module may be a software module (e.g., a code or machine-readable instruction stored on a non-transitory machine-readable medium) or a hardware module. A hardware module is a tangible unit that is capable of performing a specific operation and may be configured or arranged in a specific manner. A hardware module may include permanently configured dedicated circuits 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 may also include programmable logic or circuits (e.g., contained in a general-purpose processor or other programmable processor) that are temporarily configured by software to perform certain operations. The decision to implement a hardware module in a dedicated and permanently configured circuit or in a temporarily configured circuit (e.g., configured by software) may be driven by cost and time considerations.

[0152] When implemented in software, the techniques may be provided as part of an operating system, a library used by multiple applications, a specific software application, etc. The software may be executed by one or more general-purpose processors or one or more special-purpose processors.

[0153] After reading this disclosure, those skilled in the art will appreciate additional additional and alternative structural and functional designs for handling mobility between base stations through the principles disclosed herein. Therefore, although specific embodiments and applications have been shown and described, it is to be understood that the disclosed embodiments are not limited to the precise constructions and components disclosed herein. Various modifications, changes and variations may be made to the arrangement, operation and details of the methods and devices disclosed herein without departing from the spirit and scope defined in the appended claims, which will be apparent to those of ordinary skill in the art.

[0154] Example 1. A method in a user equipment (UE) for managing a power coordination configuration when performing a dual active protocol stack (DAPS) procedure, the method comprising: receiving, by processing hardware and from a radio access network (RAN), a power coordination configuration for the UE to apply when communicating with a source cell and a target cell of the RAN to constrain uplink power; initiating, by the processing hardware, the DAPS procedure according to the power coordination configuration; and releasing, by the processing hardware, the power coordination configuration in response to detecting a trigger condition.

[0155] Example 2. The method according to Example 1, wherein the trigger condition comprises: connecting to the target cell when performing a DAPS procedure.

[0156] Example 3. The method according to Example 1 or 2, wherein the triggering condition comprises: receiving an indication from the RAN via the target cell that the UE is to release the power coordination configuration.

[0157] Example 4. The method according to Example 1, wherein the trigger condition comprises: failure to connect to the target cell when performing the DAPS procedure.

[0158] Example 5. The method according to Example 4, further comprising: re-establishing a radio connection between the UE and the RAN.

[0159] Example 6. The method according to example 4 or 5 further comprises: transmitting, via the source cell, to the RAN an indication that the UE has failed to connect to the target cell.

[0160] Example 7. The method according to any of the preceding examples, wherein: the DAPS process is a DAPS handover process.

[0161] Example 8. The method according to Example 7, wherein the DAPS switching process causes the UE to switch between: (i) between a first MN and a second MN when the UE operates in an SC; (ii) between a first SN and a second SN when the UE operates in a DC; (iii) between a source cell of the MN and a target cell of the MN when the UE operates in an SC; or (iv) between a first distributed unit (DU) of a distributed base station and a second DU of the distributed base station.

[0162] Example 9. The method of any one of Examples 1-6, wherein: the DAPS procedure is a DAPS primary-secondary cell (PSCell) change procedure.

[0163] Example 10. The method according to Example 9, wherein the DAPS PSCell change procedure causes the UE to switch between: (i) between a first SN and a second SN; (ii) between a source cell of the SN and a target cell of the SN; or (iii) between a first distributed unit (DU) of a distributed base station and a second DU of the distributed base station.

[0164] Example 11. A method in a RAN for managing a power coordination configuration when performing a DAPS procedure with a UE, the method comprising: determining, by processing hardware, that the UE will perform a DAPS procedure according to the power coordination configuration to connect to a target cell and disconnect from a source cell after connecting to the target cell; transmitting, by processing hardware, the power coordination configuration to the UE for the UE to apply when communicating with the source cell and the target cell to constrain uplink power; and causing the UE to release the power coordination configuration in response to detecting a trigger condition.

[0165] Example 12. The method according to Example 11, wherein the trigger condition comprises: after performing the DAPS procedure, determining that the UE is connected to the RAN via the target cell.

[0166] Example 13. The method according to Example 11 or 12, wherein the triggering condition comprises: transmitting, via the target cell, to the UE an indication that the UE is to release the power coordination configuration.

[0167] Example 14. The method of any of Examples 11-13, wherein transmitting the power coordination configuration comprises transmitting the power coordination configuration to the UE in a handover command message or an RRC container message.

[0168] Example 15. The method of any of Examples 11-14, further comprising: releasing, by the processing hardware, the power coordination configuration at the RAN after transmitting the power coordination configuration.

[0169] Example 16. The method of Example 15, wherein releasing the power coordination configuration comprises releasing the power coordination configuration in response to receiving a failure information message from the UE.

[0170] Example 17. The method of any of Examples 11-16, wherein: the DAPS procedure is a DAPS handover procedure.

[0171] Example 18. The method of any one of Examples 11-16, wherein: the DAPS procedure is a DAPS primary secondary cell (PSCell) change procedure.

Claims

1. A method for managing power coordination configuration in a user equipment UE when performing a dual active protocol stack DAPS process, the method comprising: receiving, by a UE from a radio access network RAN, a power coordination configuration for application by the UE to constrain uplink power when communicating with a source cell and a target cell of the RAN; The UE initiates a DAPS process according to the power coordination configuration; as well as In response to detecting a failure when performing the DAPS procedure, releasing, by the UE, the power coordination configuration.

2. The method according to claim 1, wherein: The failures include: The UE fails to connect to the target cell when performing the DAPS procedure.

3. The method according to claim 2, further comprising: An indication that the UE failed to connect to the target cell is transmitted by the UE to the RAN via the source cell.

4. The method according to any preceding claim, further comprising: A radio connection is re-established between the UE and the RAN.

5. The method according to any one of claims 1 to 3, wherein: The DAPS procedure is one of a DAPS switching procedure and a DAPS primary / secondary cell PSCell change procedure.

6. A UE comprising processing hardware and configured to implement the method according to any one of claims 1-3.

7. A method in a RAN for managing power coordination configuration when performing a DAPS procedure with a UE, the method comprising: determining, by the RAN, that the UE will perform the DAPS procedure according to the power coordination configuration to connect to a target cell and disconnect from a source cell after connecting to the target cell; transmitting, by the RAN, the power coordination configuration to the UE, for the UE to apply to constrain uplink power when communicating with the source cell and the target cell; and In response to receiving a failure information message from the UE, causing the UE to release the power coordination configuration.

8. The method according to claim 7, wherein: The RAN transmitting the power coordination configuration includes transmitting the power coordination configuration to the UE in a handover command message or an RRC container message.

9. The method according to claim 7, wherein: The DAPS process is a DAPS switching process or a DAPS primary / secondary cell PSCell change process.

10. A base station comprising processing hardware and configured to implement the method of any one of claims 7-9.

Images