Dual Active Protocol Stack Handover

Abstract

In wireless communication, the device can perform handover between cells of network access without interruption for inter-cell mobility. In Dual Active Protocol Stack (DAPS) handover, after successfully accessing the target cell, the User Equipment (UE) maintains simultaneous connection with the source node and the target node until releasing the source cell. The source node can generate power and / or resource adjustment parameters or configurations that are transmitted to the target node during handover. If there is a Centralized Unit (CU) separated from the Distributed Unit (DU), the CU or DU can generate and / or transmit the parameters / configurations to the peer node.

Description

[Technical Field]

[0001] Technical Field TECHNICAL FIELD This document relates generally to wireless communications, and more particularly, to communication systems for mobile devices where improved signaling may be required to reduce mobility interruptions. [Background technology]

[0002] background Wireless communication technologies are moving the world towards an increasingly connected and networked society. Wireless communication relies on efficient management and allocation of network resources between user mobile stations and radio access network nodes (including, but not limited to, radio base stations). Next-generation networks are expected to provide high-speed, low-latency, and ultra-reliable communication capabilities to meet the requirements of various industries and users. User mobile stations or User Equipment (UE) are becoming more complex, and the amount of data communicated is constantly increasing. Communication improvements should be made to improve communication, meet the reliability requirements of vertical industries, and support next-generation network services. Summary of the Invention [Means for solving the problem]

[0003] overview This document relates to methods, systems, and devices for wireless communication that allow for seamless mobility of user equipment (UE). As a user moves, the user equipment (UE) may undergo handover procedures. In a Dual Active Protocol Stack (DAPS) handover, the UE maintains simultaneous connections with the source node and the target node after successfully accessing the target cell until it releases the source cell. The source node may generate power and / or resource adjustment parameters or configurations that are transmitted to the target node during handover. If there is a Centralized Unit (CU) separated from a Distributed Unit (DU), the CU or DU may generate and / or transmit the parameters / configurations to the peer node.

[0004] In one embodiment, a wireless communication method includes transmitting a request message including a handover indication and receiving a response message to the request message including handover-related configuration based on the handover indication. The transmitting is from a base station central unit (CU) to a base station distributed unit (DU), and the receiving is received by the base station CU from the base station DU. The handover here is a dual active protocol stack (DAPS) handover, and a user equipment (UE) maintains connections with the source cell and the target cell during handover from the source cell to the target cell. The CU is a source CU, the DU is a source DU, and the source cell is within the source CU and the source DU. The request message is a UE context modification request message, and the response message is a UE context modification response message. The CU is a target CU, the DU is a target DU, and the target cell is within the target CU and the target DU. The request message is a UE context setup request message, and the response message is a UE context setup response message. The target CU and source CU are combined into a single CU. The handover indication includes an indication of DAPS handover initiation, a list of Data Radio Bearers (DRBs) information for which DAPS handover is to be initiated, or the type of DAPS handover to be initiated. The handover-related configuration includes Dual Active Protocol Stack (DAPS) handover-related adjustment configuration. The request message includes Dual Active Protocol Stack (DAPS) handover-related adjustment configuration, and the response message includes handover-related configuration of the target cell configuration. The response message includes an indication of whether the DAPS handover is accepted or rejected, or a list of DRB information indicating whether the DAPS handover is accepted or rejected for the associated DRBs.The method includes disabling, by the DU, multiple transmission and reception point (multi-TRP) operation during handover, or using, by the DU, a dual-active protocol stack (DAPS) handover-related adjustment configuration for power or resource adjustment between the source cell and the target cell during DAPS handover. The method includes transmitting a second request message to the target DU, the second request message including a DAPS handover state indication indicating that the DAPS handover is completed or the source cell is released. The method includes, after handover completion, enabling, by the DU, multiple transmission and reception point (multi-TRP) operation, or discarding, by the DU, a dual-active protocol stack (DAPS) handover-related adjustment configuration for power or resource adjustment between the source cell and the target cell during DAPS handover, the method including transmitting a third request message indicating a dual-active protocol stack (DAPS) handover-related adjustment configuration for power or resource adjustment between the source cell and the target cell during DAPS handover. The handover-related adjustment configuration includes a dual active protocol stack (DAPS) handover-related power adjustment parameter, a DAPS handover-related resource adjustment parameter, or a DAPS handover-related performance indication.

[0005] In another embodiment, a wireless communication method includes receiving a request message including a handover indication and transmitting a response message to the request message including handover-related configuration based on the handover indication. The receiving is from a base station central unit (CU) and occurs at a base station distributed unit (DU), and the transmitting is from the base station DU to the base station CU, the handover being a dual active protocol stack (DAPS) handover, and the user equipment (UE) maintains connections with the source cell and the target cell during the handover from the source cell to the target cell. The CU is a source CU, the DU is a source DU, and the source cell is within the source CU and the source DU. The request message is a UE context modification request message, and the response message is a UE context modification response message. The CU is a target CU, the DU is a target DU, and the target cell is within the target CU and the target DU. The request message is a UE context setup request message, and the response message is a UE context setup response message. The target CU and source CU are combined into a single CU. The handover indication includes an indication of DAPS handover initiation, a list of Data Radio Bearers (DRBs) information for which DAPS handover is to be initiated, or the type of DAPS handover to be initiated. The handover-related configuration includes Dual Active Protocol Stack (DAPS) handover-related adjustment configuration. The request message further includes Dual Active Protocol Stack (DAPS) handover-related adjustment configuration. The response message includes an indication of whether the DAPS handover is accepted or rejected, or a list of DRB information indicating whether the DAPS handover is accepted or rejected for the associated DRBs.The method includes disabling multi-transmit / receive point (multi-TRP) operation during handover or utilizing dual active protocol stack (DAPS) handover-related power adjustment parameters, where the DAPS handover-related resource adjustment parameters are for power or resource adjustment between the source cell and the target cell during the DAPS handover. The method includes receiving a second request message, where the second request message includes a DAPS handover state indication indicating that the DAPS handover is completed or the source cell is released. The method includes enabling multi-transmit / receive point (multi-TRP) operation after handover completion or discarding the dual active protocol stack (DAPS) handover-related power adjustment parameters during the DAPS handover. The DAPS handover-related resource adjustment parameters are for power or resource adjustment between the source cell and the target cell. The method includes receiving a third request message indicating a dual active protocol stack (DAPS) handover-related adjustment configuration for performing power adjustment or resource adjustment between the source cell and the target cell during a DAPS handover, wherein the handover-related adjustment configuration includes a dual active protocol stack (DAPS) handover-related power adjustment parameter, a DAPS handover-related resource adjustment parameter, or a DAPS handover-related capability indication.

[0006] In one embodiment, a wireless communications device includes a processor and a memory, the processor configured to read code from the memory and implement any of the above-described embodiments.

[0007] In one embodiment, a computer program product includes computer readable program medium code stored thereon that, when executed by a processor, causes the processor to implement any of the above-described embodiments.

[0008] In one embodiment, a wireless communication device is provided that includes a processor and a memory, where the processor is configured to read code from the memory and perform any of the methods described in any of the embodiments. In one embodiment, a computer program product includes computer-readable program medium code stored thereon that, when executed by the processor, causes the processor to perform any of the methods described in any of the embodiments. These and other aspects and implementations thereof are described in more detail in the drawings, description, and claims. The present invention provides, for example, the following. (Document title) Claims (Item 1) 1. A wireless communication method, comprising: sending a request message including a handover indication; receiving a response message to the request message including a handover-related configuration based on the handover indication; A method comprising: (Item 2) Item 1. The method according to item 1, wherein the transmitting is from a base station central unit (CU) to a base station distributed unit (DU), the receiving is performed by the base station CU from the base station DU, the handover is a dual active protocol stack (DAPS) handover, and a user equipment (UE) maintains a connection with the source cell and the target cell during the handover from a source cell to a target cell. (Item 3) The method according to item 2, wherein the CU is a source CU, the DU is a source DU, and the source cell is within the source CU and the source DU. (Item 4) Item 4. The method according to item 3, wherein the request message is a UE context modification request message and the response message is a UE context modification response message. (Item 5) The method according to item 2, wherein the CU is a target CU, the DU is a target DU, and the target cell is within the target CU and the target DU. (Item 6) The method according to item 5, wherein the request message is a UE context setting request message and the response message is a UE context setting response message. (Item 7) 6. The method of items 3 and 5, wherein the target CU and the source CU are combined into a single CU. (Item 8) The above handover indication is DAPS handover initiation indication, a list of Data Radio Bearers (DRBs) information for which a DAPS handover is initiated, or Type of DAPS handover to be initiated Item 1. The method according to item 1, comprising at least one of the following: (Item 9) Item 4. The method according to item 3, wherein the handover-related configuration includes a Dual Active Protocol Stack (DAPS) handover-related adjustment configuration. (Item 10) Item 6. The method of item 5, wherein the request message further includes a Dual Active Protocol Stack (DAPS) handover-related adjustment configuration, and the response message includes the handover-related configuration for the target cell configuration. (Item 11) The response message above is An indication that the DAPS handover has been accepted or rejected, or A list of DRB information indicating whether the DAPS handover was approved or rejected for the associated DRB Item 6. The method of item 5, further comprising at least one of: (Item 12) causing the DU to disable multi-transmission / reception point (multi-TRP) operation during the handover; or During a DAPS handover, the DU uses the Dual Active Protocol Stack (DAPS) handover-related adjustment configuration to perform power or resource adjustment between the source cell and the target cell. 6. The method according to item 3 or 5, further comprising at least one of: (Item 13) sending a second request message to the target DU, wherein the second request message includes a DAPS handover status indication indicating that the DAPS handover is completed or the source cell is released; Item 6. The method of item 5, further comprising: (Item 14) After the handover is completed, enabling the DU to operate in multi-transmission / reception point (multi-TRP) mode; or During a DAPS handover, the DU discards the Dual Active Protocol Stack (DAPS) handover-related adjustment configuration for performing power adjustment or resource adjustment between the source cell and the target cell. Item 14. The method of item 13, further comprising at least one of: (Item 15) Sending a third request message indicating a Dual Active Protocol Stack (DAPS) handover-related adjustment configuration for power adjustment or resource adjustment between the source cell and the target cell during a DAPS handover. The method according to item 2, further comprising: (Item 16) The above Dual Active Protocol Stack (DAPS) handover related adjustment configuration is as follows: Dual Active Protocol Stack (DAPS) handover-related power adjustment parameters; DAPS handover related resource adjustment parameters, or DAPS handover related performance indications 16. The method according to any one of items 1 to 15, comprising at least one of: (Item 17) 1. A wireless communication method, comprising: receiving a request message including a handover indication; sending a response message to the request message including a handover-related configuration based on the handover indication; A method comprising: (Item 18) Item 18. The method according to item 17, wherein the receiving is performed from a base station central unit (CU) to a base station distributed unit (DU), the transmitting is transmitted by the base station DU to the base station CU, the handover is a dual active protocol stack (DAPS) handover, and a user equipment (UE) maintains a connection with the source cell and the target cell during the handover from a source cell to a target cell. (Item 19) Item 19. The method according to item 18, wherein the CU is a source CU, the DU is a source DU, and the source cell is within the source CU and the source DU. (Item 20) 20. The method according to item 19, wherein the request message is a UE context modification request message and the response message is a UE context modification response message. (Item 21) Item 19. The method according to item 18, wherein the CU is a target CU, the DU is a target DU, and the target cell is within the target CU and the target DU. (Item 22) Item 22. The method according to item 21, wherein the request message is a UE context setting request message and the response message is a UE context setting response message. (Item 23) 22. The method of claim 19, wherein the target CU and the source CU are combined into a single CU. (Item 24) The above handover indication is DAPS handover initiation indication, a list of Data Radio Bearers (DRBs) information for which a DAPS handover is initiated, or Type of DAPS handover to be initiated Item 18. The method according to item 17, comprising at least one of the following: (Item 25) 20. The method of claim 19, wherein the handover-related configuration includes a Dual Active Protocol Stack (DAPS) handover-related adjustment configuration. (Item 26) 22. The method of claim 21, wherein the request message further includes a Dual Active Protocol Stack (DAPS) handover-related adjustment configuration. (Item 27) The response message above is An indication that the DAPS handover has been accepted or rejected, or A list of DRB information indicating whether the DAPS handover was approved or rejected for the associated DRB 22. The method according to item 21, comprising at least one of the following: (Item 28) Disabling multi-transmit / receive point (multi-TRP) operation during said handover, or Using the above Dual Active Protocol Stack (DAPS) handover-related power adjustment parameters and further comprising at least one of 22. The method according to item 19 or 21, wherein the DAPS handover-related resource adjustment parameters are for performing power adjustment or resource adjustment between the source cell and the target cell during a DAPS handover. (Item 29) receiving a second request message, the second request message including a DAPS handover status indication indicating that the DAPS handover is completed or the source cell is released; 22. The method of claim 21, further comprising: (Item 30) Enabling multi-transmit / receive point (multi-TRP) operation after handover is complete, or Discarding Dual Active Protocol Stack (DAPS) handover-related power adjustment parameters and further comprising at least one of 30. The method according to claim 29, wherein the DAPS handover-related resource adjustment parameters are for performing power adjustment or resource adjustment between the source cell and the target cell during a DAPS handover. (Item 31) Item 19. The method of item 18, further comprising receiving a third request message indicating a dual active protocol stack (DAPS) handover-related adjustment configuration for performing power adjustment or resource adjustment between the source cell and the target cell during a DAPS handover. (Item 32) The above Dual Active Protocol Stack (DAPS) handover related adjustment configuration is as follows: Dual Active Protocol Stack (DAPS) handover-related power adjustment parameters; DAPS handover related resource adjustment parameters, or DAPS handover related performance indications 32. The method according to any one of items 17 to 31, comprising at least one of: (Item 33) 33. A wireless communication device comprising a processor and a memory, the processor configured to read code from the memory and perform a method according to any one of items 1 to 32. (Item 34) 33. A computer program product, the computer program product including computer-readable program medium code stored thereon, the code, when executed by a processor, causing the processor to perform the method of any of items 1 to 32. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 shows an embodiment of a base station.

[0010] [Figure 2] FIG. 2 illustrates one embodiment of a Random Access (RA) messaging environment.

[0011] [Figure 3] FIG. 3 shows the network architecture of the base station central unit (CU) and the base station distributed unit (DU).

[0012] [Figure 4] FIG. 4 illustrates one embodiment of a user equipment (UE) for intra-DU mobility.

[0013] [Figure 5] FIG. 5 illustrates one embodiment of a user equipment (UE) for intra-CU and inter-DU mobility.

[0014] [Figure 6] FIG. 6 illustrates one embodiment of a user equipment (UE) for inter-CU mobility.

[0015] [Figure 7] FIG. 7 illustrates an embodiment of a handover (HO) of a dual active protocol stack (DAPS).

[0016] [Figure 8] FIG. 8 illustrates one embodiment of a string of uplink resource adjustments.

[0017] [Figure 9] FIG. 9 illustrates one embodiment of distributed unit (DU) and central unit (CU) communication for intra-CU and inter-DU handover (HO).

[0018] [Figure 10] FIG. 10 illustrates another embodiment of distributed unit (DU) and central unit (CU) communication for intra-CU and inter-DU handover (HO).

[0019] [Figure 11] FIG. 11 illustrates one embodiment of distributed unit (DU) and central unit (CU) communication for inter-CU handover (HO).

[0020] [Figure 12] FIG. 12 illustrates another embodiment of distributed unit (DU) and central unit (CU) communication for inter-CU handover (HO). DETAILED DESCRIPTION OF THE INVENTION

[0021] Detailed Description A detailed description of the present disclosure will now be provided with reference to the accompanying drawings, which form a part hereof and which show, by way of illustration, specific examples of embodiments. It should be noted, however, that the present disclosure can be embodied in a variety of different forms. Accordingly, it is intended that the subject matter as directed or claimed should not be construed as limited to any of the embodiments described below.

[0022] Throughout this specification and the claims, terms may have subtly different meanings suggested or implied by context beyond their explicitly stated meanings. Similarly, the phrases "in one embodiment" or "in an embodiment" used herein do not necessarily refer to the same embodiment, and the phrases "in another embodiment" or "in another embodiment" used herein do not necessarily refer to different embodiments. The phrases "in one embodiment" or "in an embodiment" used herein do not necessarily refer to the same embodiment, and the phrases "in another embodiment" or "in another embodiment" used herein do not necessarily refer to different embodiments. For example, the claimed subject matter is intended to include any whole or partial combination of exemplary embodiments or implementations.

[0023] Generally, terminology will be understood, at least in part, from its usage in context. For example, terms such as "and," "or," and "and / or" as used herein may have a variety of meanings that may depend, at least in part, on the context in which such terms are used. "Or," typically used to link lists such as A, B, or C, is intended herein to mean A, B, and C, used in an inclusive sense, as well as A, B, or C, used in an exclusive sense. Additionally, the terms "one or more" or "at least one" as used herein can be used to describe any feature, structure, or characteristic in a singular sense, or can be used to describe a combination of features, structures, or characteristics in a plural sense, depending, at least in part, on the context. Similarly, terms such as "a," "an," and "the" are understood to convey singular or plural usage, again, at least in part, depending on the context. Additionally, the terms "based on" or "determined by" are understood not to necessarily convey an exclusive set of factors; instead, they may take into account additional factors, not necessarily explicitly stated, again, depending, at least in part, on the context.

[0024] Radio resource control (RRC) is a protocol layer between a UE and a base station at the IP level (network layer). Various radio resource control (RRC) states are possible, such as RRC_CONNECTED, RRC_INACTIVE, and RRC_IDLE. RRC messages are transmitted via the Packet Data Convergence Protocol (PDCP). As previously mentioned, a UE can transmit data via a Random Access Channel (RACH) protocol or a Configured Grant (CG) protocol. CG may be used to reduce waste of periodically allocated resources by allowing multiple devices to share the periodic resources. To eliminate packet transmission delays and increase utilization of allocated periodic radio resources, a base station or node can allocate CG resources. The CG protocol is merely one example of a communication protocol, and other implementations are possible, including but not limited to RACH. The wireless communication described herein may be by way of wireless access.

[0025] There may be a master node (MN) and one or more secondary nodes (SNs). The MN contains a master cell group (MCG), and each SN may contain a secondary cell group (SCG). The MCG is a cell group provided by the master node (MN), and the SCG is a cell group provided by the secondary node (SN). The MCG contains a primary cell (PCell) and one or more secondary cells (SCells). The SCG may contain a primary secondary cell (PSCell) and one or more secondary cells (SCells). Each primary cell may be connected to multiple secondary cells. The primary cell (PCell, PSCell) is the master cell of its respective group (MCG, SCG, respectively) and can initiate initial access. The primary cell may be used for signaling, which is sometimes called a special cell (spCell), where spCell = PCell + PSCell. The inter-cell mobility described in these embodiments may be based on PCells, PSCells, and / or SCells, which may be referred to as source and target cells as described.

[0026] A user equipment (UE) device may move between nodes or cells, in which case a handover or change / addition procedure may occur to improve network reliability for the moving UE. The movement may be from a source cell to a target cell based on the number of possible target cells, called candidates. Movement between cells may also involve multiple target cells, which are potential candidate cells. Below, a description of conditional handover (CHO) and conditional PSCell addition / change (CPAC) is provided. CPAC may include conditional PSCell change (CPC) and / or conditional PSCell addition (CPA).

[0027] Conditional handover (CHO) can reduce handover interruption time and improve mobility reliability. CHO is a handover that is executed in a UE when one or more execution conditions are met. When the UE receives a CHO configuration, it can evaluate the execution condition(s) and can stop evaluating the execution condition(s) when a handover is triggered. The CHO configuration can include a configuration of a candidate PCell generated by a candidate target node and the execution condition(s) corresponding to the candidate cell.

[0028] Conditional PSCell Addition / Modification (CPAC) can involve a UE having a network configuration to initiate access to a candidate PSCell to consider whether the PSCell is suitable for SN addition or SN change, including intra-SN change. This consideration can be based on configured condition(s). UEs in a wireless network can operate in dual connectivity (DC), including intra-E-UTRA DC or multi-radio DC (MR-DC). In an intra-E-UTRA DC embodiment, both the MN and SN provide E-UTRA access. In an MR-DC embodiment, one node can provide New Radio (NR) access, and another node provides E-UTRA or NR access.

[0029] As described below with respect to FIGS. 1-6, a network provider may include multiple network nodes (i.e., base stations) for providing network access to user equipment (UE) devices. The network nodes are referred to as base stations in some embodiments. FIGS. 4-6 illustrate cell mobility, in which a UE device moves between cells. Control signals may be used to facilitate this mobility. Mobility may also be referred to as handover (HO) or the handover process. Dual Active Protocol Stack (DAPS) handover can reduce mobility interruptions. DAPS HO can perform power and / or resource adjustments between the source and target cells. In a DAPS-based handover procedure, a user equipment (UE) maintains simultaneous connections with the source and target cells after successfully randomly accessing the target cell until it releases the source cell. FIG. 7 illustrates an example of DAPS HO.

[0030] Specifically, during HO preparation, the source node can generate power / resource adjustment parameters / configurations and then transmit them to the target node. If there is a Centralized Unit (CU) separated from the Distributed Unit (DU), the CU or DU can generate and / or transmit the parameters / configurations to the peer node. Furthermore, the target DU may need to know when to begin / complete DAPS HO (e.g., for resource scheduling, disabling / enabling some features that cannot coexist with DAPS HO, etc.). Figures 9-12 illustrate examples of CU / DU communication for DAPS HO.

[0031] FIG. 1 illustrates one embodiment of a base station 102. A base station may also be referred to as a radio network node and may be the network nodes (e.g., master node "MN," secondary node "SN," and source / target nodes) illustrated in FIGS. 3A-7B. In a mobile communication context, the base station 102 may be further distinguished as a Node B (NB, e.g., eNB or gNB). An exemplary base station may include wireless Tx / Rx circuitry 113 for receiving and transmitting to and from a user equipment (UE) 104. The base station may also include network interface circuitry 116 for coupling the base station to a core network 110, e.g., optical or wired interconnection, Ethernet, and / or other data transmission media / protocols.

[0032] The base station may also include system circuitry 122. The system circuitry 122 may include a processor 124 and / or a memory 126. The memory 126 may include an operation unit 128 and control parameters 130. The operation unit 128 may include instructions for execution by one or more processors 124 to support base station functionality. For example, the operation unit may process random access transmission requests from multiple UEs. The control parameters 130 may include parameters or support the execution of the operation unit 128. For example, the control parameters may include network protocol settings, random access messaging formatting rules, bandwidth parameters, radio frequency mapping assignments, and / or other parameters.

[0033] 2 illustrates an example of a random access messaging environment 200. In this random access messaging environment, a UE 104 can communicate with a base station 102 over a random access channel 252. In this example, the UE 104 supports one or more subscriber identity modules (SIMs), such as SIM1 202. An electrical and physical interface 206 connects SIM1 202 to the rest of the user equipment hardware, for example, via a system bus 210.

[0034] The mobile device 200 includes a communications interface 212, a system logic 214, and a user interface 218. The system logic 214 may include any combination of hardware, software, firmware, or other logic. The system logic 214 may be implemented using, for example, one or more systems on a chip (SoC), application specific integrated circuits (ASIC), discrete analog and digital circuits, and other circuits. The system logic 214 is part of the implementation of any desired functionality in the UE 104. In this regard, system logic 214 may include, by way of example, logic to facilitate decoding and playing music and video, for example, decoding and playing MP3, MP4, MPEG, AVI, FLAC, AC3, or WAV files, executing applications, accepting user input, saving and retrieving application data, establishing, maintaining, and terminating cellular calls or data connections, for example, Internet connections, establishing, maintaining, and terminating wireless network connections, Bluetooth connections, or other connections, and displaying related information on user interface 218. User interface 218 and input 228 may include a graphical user interface, a touch-sensitive display, haptic feedback or other tactile output, voice or facial recognition input, buttons, switches, speakers, and other user interface elements. Further examples of input 228 include microphones, video and still image cameras, temperature sensors, vibration sensors, rotational and orientation sensors, headset and microphone input / output jacks, universal serial bus (USB) connectors, memory card slots, radiation sensors (such as IR sensors), and other types of input.

[0035] The system logic 214 may include one or more processors 216 and memory 220. The memory 220 stores, for example, control instructions 222 that the processor 216 executes to implement desired functionality of the UE 104. Control parameters 224 provide and define configuration and operational options for the control instructions 222. The memory 220 may also store any BT, Wi-Fi, 3G, 4G, 5G, or other data 226 that the UE 104 transmits or receives via the communication interface 212. In various embodiments, system power may be provided by a power storage device, such as a battery 282.

[0036] In the communications interface 212, radio frequency (RF) transmit (Tx) and receive (Rx) circuitry 230 handles the transmission and reception of signals via one or more antennas 232. The communications interface 212 can include one or more transceivers, which can be wireless transceivers including modulation / demodulation circuitry, digital-to-analog converters (DACs), shaping tables, analog-to-digital converters (ADCs), filters, wave shapers, filters, preamplifiers, power amplifiers, and / or other logic for transmitting and receiving via one or more antennas or (for some devices) over a physical (e.g., wired) medium.

[0037] Transmitted and received signals may conform to any of a variety of formats, protocols, modulation schemes (e.g., QPSK, 16-QAM, 64-QAM, 256-QAM), frequency channels, bit rates, and encodings. As a specific example, communication interface 212 may include a transceiver supporting transmission and reception in 2G, 3G, BT, WiFi, Universal Mobile Telecommunications System (UMTS), High Speed ​​Packet Access (HSPA)+, and 4G / Long Term Evolution (LTE) standards. However, the techniques described below may be applied to other wireless communication technologies, whether or not they originate from the 3rd Generation Partnership Project (3GPP), GSM Association, 3GPP2, IEEE, or other partnership or standardization body.

[0038] Multiple RAN nodes (eNBs, gNBs, etc.) of the same or different radio access technologies (RATs) can be deployed in a specific geographical area on the same or different frequency carriers, interoperating through dual connectivity to provide shared communication services to the same target UE(s). A multi-RAT dual connectivity (MR-DC) architecture allows the master node (MN) and secondary node (SN) to be located in different locations. The Access Mobility Function (AMF) and Session Management Function (SMF) are control plane entities, and the User Plane Function (UPF) is a user plane entity in New Radio (NR) or 5GC. The signaling connection between the AMF / SMF and the master node (MN) can be a Next Generation-Control Plane (NG-C) / MN interface. The signaling connection between the MN and SN can be an Xn-Control Plane (Xn-C) interface. The signaling connection between the MN and the UE is the RRC interface of the Uu-Control Plane (Uu-C). All these connections manage the configuration and operation of the MR-DC. The user plane connection between the User Plane Function (UPF) and the MN can be an instance of the NG-U(MN) interface.

[0039] Figure 3 shows a network architecture of base station central units (CUs) and base station distributed units (DUs). Figure 3 illustrates base stations (denoted gNBs) communicating with an overall network (denoted 5GC). The base stations can communicate with each other via a control plane interface (Xn-C). One base station is shown as having one CU connected to two DUs via an F1 interface. This is just one example of a base station arrangement. In some embodiments, there may be any number of DUs connected to a single CU.

[0040] A base station can be divided into two physical entities: a central unit (CU) and a distributed unit (DU). Generally, the CU supports the upper layers of the protocol stack, such as SDAP, PDCP, and RRC, while the DU provides support for the lower layers of the protocol stack, such as RLC, MAC, and the physical layer. Except for the functions exclusively assigned to the DU, the CU can include operations for user data transfer, mobility control, radio access network sharing, session management, etc. The DU(s) are logical node(s) with a subset of base station functions and can be controlled by the CU.

[0041] A CU may be a logical node that hosts the RRC, SDAP, and PDCP protocols of a base station or that controls the operation of one or more DUs. A DU may be a logical node that hosts the RLC, MAC, and PHY layers of a base station, the operation of which is controlled at least in part by a CU. A single DU may support one or more cells. However, each cell is supported by only a single DU. Each base station may support multiple cells. As described in the embodiments herein, mobility between cells may be from different CUs or DUs, or may be internal to a CU and / or DU.

[0042] Inter-cell mobility as described herein can occur in many different implementations. There can be intra-DU mobility, where the UE changes cells within a single DU. Examples of intra-DU mobility include: 1) PCell change within one DU (which may include PCell change, accompanied by SCell change); 2) PSCell change within one DU (which may include PSCell change, accompanied by SCell change); 3) PCell change within one DU (which may include SCell change within a cell group), accompanied by PScell ​​change within one DU. In another mobility implementation, there can be intra-CU and inter-DU mobility, where the UE changes cells between different DUs but within a single CU. Examples of intra-CU and inter-DU mobility include: 1) PCell change across DUs but within one CU (which may include PCell change, accompanied by SCell change). 2) A PSCell change across DUs but within one CU (with an SCell change, which may include a PSCell change). In another mobility embodiment, there may be inter-CU mobility, where the UE changes cells between different CUs. Examples of inter-CU mobility include: 1) A PCell change across CUs (with an SCell change, which may include a PCell change). 2) A PSCell change across CUs (with an SCell change, which may include a PSCell change). In another embodiment, there may be a SCell change / addition, and examples of this may include an SCell addition / addition within one cell group. Figures 4 to 6 illustrate embodiments of UE mobility between cells.

[0043] FIG. 4 illustrates one embodiment of intra-DU mobility for user equipment (UE). A base station may include a CU and at least one DU. In this embodiment, a single DU with multiple cells is shown. Cell 1 and Cell 2 are both from a single DU. In this example, a UE 402 may move from Cell 1 to Cell 2, and FIG. 4 illustrates the trajectory of the UE from Cell 1 to Cell 2. Inter-cell mobility may occur when the UE 402 is located between two cells and moves to a third location within Cell 2. This is intra-DU mobility because the UE is moving between cells within a single DU.

[0044] FIG. 5 illustrates an embodiment of intra-CU and inter-DU mobility for user equipment (UE). In this embodiment, a base station may include a CU and two DUs (DU_1 and DU_2). While each DU can have multiple cells, in this example, each DU is shown serving a single cell, such as DU_1 serving cell 1 and DU_2 serving cell 2. In this example, a UE 502 can move from cell 1 to cell 2, and FIG. 5 depicts the UE's trajectory from cell 1 to cell 2, which also results in movement from DU_1 to DU_2. Mobility from a cell may occur when a UE 402 is located between two cells and moves to a third location within cell 2. Because the UE is moving between cells within a single CU, this is intra-CU mobility. However, because the UE is moving between different DUs, this is also inter-DU mobility.

[0045] FIG. 6 illustrates an embodiment of inter-CU mobility for a user equipment (UE). In this embodiment, a base station may include multiple CUs (CU_1 and CU_2). While each CU may include multiple DUs, in this example, each CU is shown as having one corresponding DU (CU_1 has DU_1, and CU_2 has DU_2). Each DU is shown with multiple cells. In this example, the UE trajectory of UE 602 passes through Cell_2 to Cell_3, inter-CU location 604 (between CU_1 and CU_2), Cell_5, and Cell_6. As the UE moves, mobility can change cells and move between multiple cells as shown. Because UE 602 switches cells from CU_1 to CU_2 (at inter-CU location 604), this movement is referred to as inter-CU mobility.

[0046] DAPS Handover Dual Active Protocol Stack (DAPS) handover (HO) is one example of a continuous HO type. The embodiments described herein are applicable to any type of HO, whether it is continuous or limited. For simplicity, this embodiment uses DAPS HO, but this is only one example of an HO type. Other HO types may include HO without interruption or HO where the UE maintains connectivity with the source and target cells during HO.

[0047] FIG. 7 illustrates an embodiment of a Dual Active Protocol Stack (DAPS) Handover (HO). To reduce mobility interruptions, a Dual Active Protocol Stack (DAPS)-based handover procedure can be used. In the DAPS-based handover procedure, after a UE successfully randomly accesses the target cell, it maintains simultaneous connections with the source cell and the target cell until it releases the source cell. FIG. 7 illustrates that, in block 1, the source node configures a UE measurement procedure and the UE reports according to the measurement configuration. In block 2, based on the Measurement Report and RRM information, the source node decides to hand over the UE. In block 3, the source node sends a Handover Request message to the target node, including a DAPS indicator indicating that a DAPS HO is requested. In block 4, admission control is performed by the target node. In block 5, the target node decides to accept the DAPS HO and sends a Handover Request Acknowledge to the source node, including a DAPS response indicator indicating whether the DAPS HO is accepted. In block 6, the source node triggers Uu handover by sending an RRCReconfiguration message to the UE. In the case of a DAPS-configured DRB, the source node does not stop transmitting downlink packets until it receives a Handover Success message from the target node in step 9a. In block 7a, the source node sends an Early Status Transfer message to communicate the uplink / downlink PDCP SN status. Alternatively, in block 7, the source node sends an SN Status Transfer message to the target node to communicate the uplink / downlink PDCP SN status.In block 8, the UE initiates random access to the target cell and completes the RRC handover procedure by sending an RRCReconfigurationComplete message to the target node. In a DAPS HO embodiment, the UE may not detach from the source cell upon receiving the RRCReconfiguration message. Upon receiving an explicit release from the target node in step 9c, the UE releases the source connection and configuration. For DAPS HO, in block 9a, the target node sends a Handover Success message to the source node to notify that the UE has successfully accessed the target cell. In response, in block 9b, the source node sends an SN Status Transfer message for the DAPS-configured DRB. In block 9c, the target node sends an RRCReconfiguration message to the UE, including a DAPS source release indication to indicate the source connection and configuration. In response, in block 10, a path switch may occur.

[0048] Adjustment configuration 3 illustrates an embodiment in which the CU and DU are split (i.e., a CU / DU split case), and the source CU / DU or target CU / DU can determine / generate the DAPS-related coordination configuration to be used in the source cell and the target cell during DAPS HO. As described below, CU / DU coordination and / or interaction can be for DAPS-related coordination configuration.

[0049] The DAPS-related adjustment configuration may include at least one of the following configurations: ·DAPS related UL power adjustment parameters / configuration. ·DAPS related resource tuning parameters / configurations. DAPS-related performance indications, e.g., the index of FeatureSetUplinkPerCC and / or FeatureSetDownlinkPerCC selected by the source cell.

[0050] There can be several alternative embodiments for generating the DAPS-related adjustment configuration and transferring it between the CU and the DU. Four exemplary embodiment examples are described below. In a first alternative embodiment, the DU decides on the DAPS-related adjustment configuration. In this embodiment, the CU sends a DAPS HO indication to the DU. This indication, also called an indicator, can be part of the handover. It is sometimes called a DAPS HO indication. This indication indicates at least one of the following: ·DAPS HO is prepared / configured / requested / started. · A list of DRB information for which DAPS HOs are prepared, configured, requested, and / or initiated for the relevant DRBs. The type of DAPS HO being prepared, configured, requested, and / or initiated (e.g., inter-frequency DAPS HO, intra-frequency DAPS HO); or ·DAPS HO specific configurations (UL power adjustment configuration, resource adjustment configuration, DAPS related performance indications, etc.).

[0051] The DU may generate a DAPS-related adjustment configuration and send it to the CU (eg, in response to receiving a DAPS HO indicator from the CU, or an inter-frequency DAPS HO indicator).

[0052] In a second alternative embodiment, the CU can determine the DAPS-related adjustment configuration. In this embodiment, the CU generates the DAPS-related adjustment configuration and sends it to the DU.

[0053] In a third alternative embodiment, the DU generates a DAPS-related adjustment configuration and sends it to the CU (e.g., in response to receiving a DAPS HO indicator from the CU or an inter-frequency DAPS HO indicator). If the CU wants to update or change this configuration, the CU can generate and send an updated DAPS-related adjustment configuration to the DU.

[0054] In a fourth alternative embodiment, the CU generates a DAPS-related adjustment configuration and sends it to the DU. If the DU wants to update / change this configuration, the DU can generate an updated DAPS-related adjustment configuration and send it to the CU.

[0055] The indication transferred from the CU to the DU can be configured in several ways. In a first embodiment, this indication can be configured by the F1 interface. This indication (e.g., DAPS HO Indicator or DAPS HO Type) is configured as an information element in an F1-C message (e.g., a UE CONTEXT MODIFICATION REQUEST message or a UE CONTEXT SETUP REQUEST message). In a second embodiment, this indication can be configured for an RRC message. In other words, this indication (e.g., DAPS HO Indicator or DAPS HO Type) is in an RRC message (e.g., a CG-ConfigInfo, CG-Config, or HandoverPreparationInformation message). The RRC message can be encapsulated as an OCTET STRING / container in an F1-C message (e.g., a UE CONTEXT MODIFICATION REQUEST message or a UE CONTEXT SETUP REQUEST message).

[0056] The DAPS-related adjustment configuration transferred between the DU and the CU can be configured in various ways. In a first embodiment, the DAPS-related adjustment configuration is directly included as an information element (e.g., DAPS HO Power Coordination, DAPS HO Resource Coordination) in the F1-C message (e.g., UE CONTEXT MODIFICATION REQUEST / RESPONSE message or UE CONTEXT SETUP REQUEST / RESPONSE message). This information element can be included in the DU in the CU RRC Information IE in the F1-C message. In a second embodiment, the DAPS-related adjustment configuration encapsulated as an OCTET STRING / container (e.g., powerCoordination, ConfigRestrictInfoDAPS, DAPS Resource Coordination Transfer Container) can be included in the F1-C message (e.g., UE CONTEXT MODIFICATION REQUEST / RESPONSE message or UE CONTEXT SETUP REQUEST / RESPONSE message). The OCTET STRING / container can be included in the CU RRC Information IE in the F1-C message within the DU.

[0057] The DAPS-related adjustment configurations described herein may include various parameters, example parameters include power adjustment parameters and / or resource adjustment parameters, example parameters for each of which are described below.

[0058] Power Adjustment Parameters DAPS-related uplink (UL) power adjustment parameters / configurations may include various information. Power adjustment may also be referred to as at least one of the following items: ·The maximum total transmit power used by the UE in the source cell group during a DAPS handover (e.g., DAPS Source Power, or p-DAPS-Source). · The maximum total transmission power used by the UE in the target cell group during DAPS handover (e.g., DAPS Target Power, or p-DAPS-Target). The uplink power sharing mode (Uplink Power Sharing DAPS Mode, or uplinkPowerSharingDAPS-Mode) that the UE uses in DAPS handover. This mode can be semi-static-mode1, semi-static-mode2, or dynamic. Alternatively, It may be adjustment support information indicating whether UL power adjustment between the source cell and the target cell is required.

[0059] Resource Tuning Parameters The HO indication may include resource adjustment parameters in addition to power adjustment parameters. In some embodiments, these parameters may be combined or may be separate parameters. DAPS-related resource adjustment parameters / configurations include at least one of the following: · Source / target cell ID (e.g. CGI, PCI with carrier frequency). · Uplink (UL) coordination information. Downlink (DL) coordination information. Coordination assistance information indicating whether coordination of resource utilization between the source and target cells is required; or Time Division Multiplexing (TDM) pattern information, including UL / DL reference configuration, indicating when a DAPS HO-configured UE can transmit (e.g., for a single UL transmission).

[0060] The UL / DL coordination information may include a bitmap / bit string indicating whether a particular frequency and time resource is intended for use by the source / target cell. The target node then considers resources not intended for use by the source cell as available for use by the target cell, and the source node considers resources not intended for use by the target cell as available for use by the source cell. Figure 8 shows one embodiment of an uplink resource coordination string. This string may be an example of UL coordination information.

[0061] Each position in the bitmap may represent a pair of physical resource blocks (PRBs) within a subframe. A value of "0" indicates an SpCell resource not intended for use by the transmitting / target / source node for transmission, and a value of "1" indicates an SpCell resource intended for use by the transmitting / target / source node for transmission. In other embodiments, the values ​​may be swapped. The bit string moves from the first PRB pair of the first represented subframe to the last PRB pair of the same subframe, and then in the same order to the next PRB in the next subframe. Each position may only apply in positions corresponding to UL subframes. The bit string may span multiple consecutive subframes (e.g., up to 40). The first position of the UL Coordination Information may correspond to subframe 0 of the receiving node in the receiving node's radio frame with System Frame Number (SFN) = 0. The bit string may span N subframes and be N*M bits in length, where M is the PRB number within a single subframe. The UL coordination information may be repeated continuously. The same embodiment can be applied to DL resource adjustment, and each position can be applied only at the position corresponding to the DL subframe.

[0062] Referring back to the resource adjustment parameters, one example was TDM pattern information. The TDM pattern information may include at least one of the following: Subframe allocation (e.g., allocation shown in the table below) indicating the DL / UL subframe configuration, or ·HarqOffset, indicating the HARQ subframe offset that applies to the subframe designated as UL in the associated subframe allocation. [Table 1]

[0063] An example of a signaling structure for DAPS HO indication may include the following: [Table 2] [Table 3] [Table 4]

[0064] Examples of signaling structures for UL power adjustment parameters / configurations related to DAPS may include the examples shown in Tables 5-6. [Table 5] [Table 6]

[0065] In one embodiment, a HO preparation information message (e.g., HandoverPreparationInformation) may be transmitted. An example code for the message is shown below: [ka] [ka] [ka]

[0066] The following table illustrates exemplary field descriptions: [Table 7] [Table 8]

[0067] Example of signaling structure for DAPS related resource adjustment parameters / configuration: [Table 9-1] [Table 9-2] [Table 10]

[0068] In the case of inter-CU mobility, there may be several embodiments for generating / transferring DAPS-related coordination configurations between a source CU / source node and a target CU / target node. Exemplary embodiments of this generation / transfer include the following: · Option 1: The source CU / source node transfers the generated DAPS-related adjustment configuration to the target CU / target node by means of an Xn / X2 message, e.g., a handover request message. Option 1a: When the target CU / target node wants to update / change the DAPS-related coordination configuration, the target CU / target node sends the updated DAPS-related coordination configuration to the source CU / source node by an Xn / X2 message, e.g., a Handover Request Acknowledge message. · Option 2: The target CU / target node forwards the generated DAPS-related adjustment configuration to the source CU / source node by an Xn / X2 message, e.g., a Handover Request Acknowledge message. · Option 2a: When the source CU / source node wants to update / change the DAPS-related adjustment configuration, the source CU / source node sends the updated DAPS-related adjustment configuration to the target CU / node by Xn / X2 message.

[0069] DAPS related adjustment configuration can be transferred by one of the following options: Option 1: Including the configuration as an information element in the Xn / X2 message (e.g., Handover Request message or Handover Request Acknowledge message). Option 2: Include the configuration in an RRC message, e.g., a Handover Preparation Information message. The RRC message is encapsulated as an OCTET STRING / container in an Xn / X2 message, e.g., a Handover Request message.

[0070] DAPS HO Status CU / DU coordination / interaction may depend on the DAPS HO state. The DAPS HO state may be used to inform the DU when to begin / complete the DAPS HO, e.g. for resource scheduling, disabling / enabling some features that cannot coexist with DAPS HO. This may be the start of the DAPS HO. The CU sends a DAPS HO indication to the DU to indicate that the DAPS HO is prepared, configured, requested or started. The DAPS HO start indication may indicate at least one of the following: ·DAPS HO is prepared / configured / requested / started. · A list of DRB information for which the DAPS HO is prepared, configured, requested or initiated for the relevant DRB. · The type of DAPS HO being prepared, configured, requested, or initiated (e.g., inter-frequency DAPS HO, intra-frequency DAPS HO). · DAPS HO specific configurations (e.g. UL power adjustment configuration, resource adjustment configuration, or DAPS related performance indications).

[0071] In response to receiving the DAPS HO indication, the DU may perform at least one of the following: ·Consider preparing / configuring / requesting / starting DAPS HO. ·Using the received / generated DAPS related adjustment parameters / configurations for power adjustment and / or resource adjustment between the source cell and the target cell in the DAPS HO. Disable / prohibit functions / operations that cannot coexist with DAPS HO (e.g., multi-TRP). For example, the DU can disable SDM-based single DCI-based multi-TRP for a UE-specific PDSCH MAC CE by using Enhanced TCI States Activation / Deactivation.

[0072] In the DAPS HO response to receiving the DAPS HO indication from the CU, the DU can approve / reject the DAPS request or partial DAPS request (e.g., approve the DAPS request for some DRBs in the DRB list for DAPS requests and reject the DAPS request for other DRBs in the DRB list for DAPS requests). The DU sends a DAPS HO response indication to the CU. The DAPS HO response indication may include at least one of the following: · Indication that DAPS HO has been approved / rejected. · A list of DRB information indicating whether the DAPS HO has been approved / rejected by the relevant DRB.

[0073] In the case of inter-CU mobility, in response to receiving a DAPS HO response indication from the target CU, the source CU may send a DAPS HO response indication to the source DU. If the DAPS HO response indication indicates that the DAPS HO is rejected, the source DU may discard / release any previously generated / received DAPS-related coordination configuration. Figures 9-12 illustrate example communications, including the DAPS HO initiation and DAPS HO response described above.

[0074] The UE successfully transfers / switches to the target node, e.g., successfully completes a random access procedure to the target cell. The CU sends an indication to the DU indicating that the DAPS HO is completed or the source cell is released (e.g., DAPS HO Completion Indication, Source Cell Release Indication, or setting the value of DAPS HO Indication to "Complete / Release / Stop") (e.g., when the CU decides to release the source cell or generates / sends an RRC reconfiguration message including the daps-SourceRelease IE). In an embodiment, this may be when the CU successfully releases the source cell (e.g., after sending an RRC reconfiguration message including the daps-SourceRelease IE to the UE). In response to receiving the DAPS HO completion / source cell release indication, the DU may perform at least one of the following: · Consider whether the DAPS HO is completed or the source cell is released. Stop using the received / generated DAPS related adjustment parameters / configurations for power and / or resource adjustment between the source and target cells in DAPS HO. The DU can replace the old configuration with the newly received / generated configuration. Enabling / allowing features / operations that cannot coexist with DAPS HO (e.g., multi-TRP). For example, the DU can enable SDM-based single-DCI-based multi-TRP with Enhanced TCI States Activation / Deactivation for UE-specific PDSCH MAC CE.

[0075] The DAPS HO related indications transferred between the CU and the DU can be configured by one of the following options: Option 1: Including the indication (e.g., DAPS HO Indicator) as one information element in the F1-C message (e.g., UE CONTEXT MODIFICATION REQUEST / RESPONSE message or UE CONTEXT SETUP REQUEST / RESPONSE message). Option 2: Include the indication (e.g., DAPS HO Indicator) in an RRC message (e.g., CG-ConfigInfo, CG-Config, or HandoverPreparationInformation message), which is encapsulated as an OCTET STRING in an F1-C message (e.g., UE CONTEXT MODIFICATION REQUEST message or UE CONTEXT SETUP REQUEST message).

[0076] The following is an example of a signaling structure for a DAPS HO related indication: [Table 11] [Table 12] [Table 13]

[0077] The above description of DAPS HO includes transmitted indications or indicators, which may include parameters such as power and / or resource adjustments to improve performance during handover. The above description applies to the following communication embodiments described with respect to Figures 9-12.

[0078] Figure 9 shows one embodiment of communication between a distributed unit (DU) and a central unit (CU) for handover (HO). The CU and DU are described above with respect to Figure 3 and are an example of a base station. Figure 9 illustrates communication between a user equipment (UE), a source DU, a target DU, and a CU. The example shown in Figure 11 is similar to Figure 9, except that there is a source CU and a target CU.

[0079] 9 shows that downlink (DL) user data is from the CU to the source DU or UE, and uplink (UL) user data is from the UE to the source DU or CU. In block 902, a Measurement Report message is sent from the UE to the source DU. In block 904, the source DU sends a UL RRC MESSAGE TRANSFER message to the CU to convey the received Measurement Report message.

[0080] In block 906, the CU sends a UE CONTEXT MODIFICATION REQUEST message to the source DU to inquire about the latest configuration. This message may include a DAPS HO indication to the source DU to indicate that a DAPS HO is prepared, configured, initiated, or requested. The DAPS HO indication may be the HO indication / indicator described above. This indication may include a list of DRB information and / or DAPS HO-specific configuration, such as that a DAPS HO is prepared, configured, initiated, or requested for the associated DRB, or which type of DAPS HO (e.g., inter-frequency DAPS HO, intra-frequency DAPS HO) is prepared, configured, initiated, or requested.

[0081] In block 908, the source DU responds with a UE CONTEXT MODIFICATION RESPONSE message containing the complete configuration information. If a DAPS HO indication or an inter-frequency DAPS HO indication is received, the source DU may generate DAPS-related adjustment configurations (e.g., UL power adjustment parameters or configurations and / or resource adjustment parameters or configurations) and include them in the message. During the DAPS HO, the DU uses the generated adjustment configurations for power and / or resource adjustment. If a DAPS HO indication is received, the source DU may disable multi-TRP operation during the DAPS HO (e.g., disable SDM-based single DCI-based multi-TRP by Enhanced TCI States Activation / Deactivation for the UE-specific PDSCH MAC CE).

[0082] In block 910, the CU sends a UE CONTEXT SETUP REQUEST message to the target DU to create a UE context and set up one or more data bearers. The UE CONTEXT SETUP REQUEST message may include a HandoverPreparationInformation message. The UE CONTEXT SETUP REQUEST message or the HandoverPreparationInformation message may include DAPS-related adjustment configuration. This adjustment configuration may also be referred to as HO-related configuration. The UE CONTEXT SETUP REQUEST message may include a DAPS HO indication to the target DU to indicate that a DAPS HO is prepared, configured, initiated, or requested. The UE CONTEXT SETUP REQUEST message may also include a list of DRB information and / or DAPS HO-specific configuration regarding whether a DAPS HO is prepared, configured, initiated, or requested for the associated DRBs and / or which type of DAPS HO (e.g., inter-frequency DAPS HO, intra-frequency DAPS HO) is prepared, configured, initiated, or requested.

[0083] In block 912, the target DU responds to the CU with a UE CONTEXT SETUP RESPONSE message. If a DAPS HO indication is received, the target DU can disable multi-TRP operation during DAPS HO (e.g., disable SDM-based single DCI-based multi-TRP by Enhanced TCI States Activation / Deactivation for UE-specific PDSCH MAC CE). If a DAPS-related adjustment configuration is received, the target DU uses the received adjustment configuration to perform either power or resource adjustment during DAPS HO.

[0084] In block 914, the CU sends a UE CONTEXT MODIFICATION REQUEST message to the source DU. This message includes the generated RRC Reconfiguration message and indicates that data transmission to the UE is to be stopped. The RRC Reconfiguration message may include the DAPS-related adjustment configuration of the UE. The source DU also sends a Downlink Data Delivery Status frame to notify the CU of the failed downlink data transmission to the UE. In the case of a DAPS handover, the UE CONTEXT MODIFICATION REQUEST message in block 914 can indicate that data transmission is to be stopped only for DRB(s) not subject to the DAPS handover, or can indicate no data transmission at all. Alternatively, the DL RRC Message Transfer procedure can be used to convey the handover command to the UE. Once the CU learns that the UE has successfully accessed the target DU, a UE CONTEXT MODIFICATION REQUEST message is sent to the source DU indicating that data transmission for the UE is to be stopped, and the source DU sends a DDDS frame to the CU for the downlink data that was not successfully transmitted.

[0085] In block 916, the source DU forwards the received RRCReconfiguration message to the UE. In block 918, the source DU responds to the CU with a UE CONTEXT MODIFICATION RESPONSE message. In some cases, there may be an optional downlink data delivery status sent from the source DU to the CU. In block 920, the target DU performs a random access procedure. The target DU sends a Downlink Data Delivery Status frame to notify the CU. Downlink packets (e.g., PDCP PDUs) that were not successfully transmitted by the source DU are sent from the CU to the target DU. In an embodiment, it is up to the CU implementation whether the UE begins transmitting DL User Data to the DU before or after receiving the Downlink Data Delivery Status. In block 922, the UE responds to the target DU with an RRCReconfigurationComplete message. In block 924, the target DU sends a UL RRC MESSAGE TRANSFER message to the CU to convey the received RRCReconfigurationComplete message. Downlink packets are sent to the UE and / or uplink packets are sent from the UE and forwarded to the CU via the target DU.

[0086] In block 926, the target CU decides to release the source cell connection. The target CU sends a UE CONTEXT MODIFICATION REQUEST message to the source DU. This UE CONTEXT MODIFICATION REQUEST message includes the generated RRCReconfiguration message, which includes a DAPS-SourceRelease information element (IE) indicating the release of the source cell connection. The UE CONTEXT MODIFICATION REQUEST message may include an indication to the source DU that the DAPS HO is complete or that the source cell is released (e.g., by setting the value of the DAPS HO indication to "Complete / Released / Stop"). If the indication is received, the target DU may stop using DAPS-related adjustment configurations for power and / or resource adjustment during DAPS HO and / or enable multi-TRP operation during DAPS HO (e.g., by enabling SDM-based single-DCI-based multi-TRP with Enhanced TCI States Activation / Deactivation for the UE-specific PDSCH MAC CE).

[0087] In block 928, the target DU forwards the received RRCReconfiguration message to the UE. In block 930, the source DU responds to the CU with a UE CONTEXT MODIFICATION RESPONSE message. In block 932, the UE responds to the target DU with an RRCReconfigurationComplete message. In block 934, the target DU sends a UL RRC MESSAGE TRANSFER message to the CU to convey the received RRCReconfigurationComplete message. In block 936, the CU sends a UE CONTEXT RELEASE COMMAND message to the source DU. In block 938, the source DU releases the UE context and responds to the CU with a UE CONTEXT RELEASE COMPLETE message. In alternative embodiments, the order of blocks 924-938 may be different.

[0088] In an embodiment, the CU may update and / or modify the DAPS-related adjustment configuration and may send the requested / updated / new DAPS-related adjustment configuration (e.g., requested / new values ​​for DAPS-related adjustment parameters) to the source DU (e.g., via a UE CONTEXT MODIFICATION REQUEST message) in block 914. Upon receiving the requested / new / updated configuration, the source DU uses the received configuration to perform either power or resource adjustment during the DAPS HO.

[0089] FIG. 10 illustrates another embodiment of communication between a distributed unit (DU) and a central unit (CU) for handover (HO). The CU and DU are as described above with reference to FIG. 3 and are an example of a base station. FIG. 10 illustrates communication between a user equipment (UE), a source DU, a target DU, and a CU. In block 1002, a Measurement Report message is sent from the UE to the source DU. In block 1004, the source DU sends a UL RRC MESSAGE TRANSFER message to the CU to convey the received Measurement Report message. In block 1006, the CU sends a UE CONTEXT MODIFICATION REQUEST message to the source DU to inquire about the latest configuration. In block 1008, the source DU responds with a UE CONTEXT MODIFICATION RESPONSE message containing the complete configuration information.

[0090] In block 1010, the CU sends a UE CONTEXT SETUP REQUEST message to the target DU to create a UE context and set up one or more data bearers. This message may include a DAPS HO indication to the source DU to indicate that a DAPS HO is prepared, configured, initiated, or requested. The DAPS HO indication may be the HO indication / indicator described above. This indication may include a list of DRB information and / or DAPS HO-specific configuration, such as that a DAPS HO is prepared, configured, initiated, or requested for the associated DRB, or which type of DAPS HO (e.g., inter-frequency DAPS HO, intra-frequency DAPS HO) is prepared, configured, initiated, or requested.

[0091] The UE CONTEXT SETUP REQUEST message may include a HandoverPreparationInformation message. The UE CONTEXT SETUP REQUEST message or the HandoverPreparationInformation message may include DAPS-related adjustment configurations. This adjustment configuration may also be referred to as HO-related configurations.

[0092] In block 1012, the target DU responds to the CU with a UE CONTEXT SETUP RESPONSE message. If a DAPS HO indication is received, the target DU can disable multi-TRP operation during DAPS HO (e.g., disable SDM-based single DCI-based multi-TRP by Enhanced TCI States Activation / Deactivation for UE-specific PDSCH MAC CE). If a DAPS-related adjustment configuration is received, the target DU uses the received adjustment configuration to perform power and / or resource adjustment during DAPS HO.

[0093] In block 1014, the CU sends a UE CONTEXT MODIFICATION REQUEST message to the source DU. This UE CONTEXT MODIFICATION REQUEST message includes the generated RRC Reconfiguration message and indicates that data transmission for the UE is to be stopped. The RRC Reconfiguration message may include a DAPS-related adjustment configuration for the UE. The CU may include a DAPS HO indication and / or a DAPS-related adjustment configuration in the message. If an adjustment configuration is received, the source DU uses the received configuration to perform power and / or resource adjustment during DAPS HO. To notify the CU that downlink data transmission to the UE has failed, the source DU may send a Downlink Data Delivery Status frame. If the source DU receives DAPS-related information (e.g., DAPS HO indication, DAPS-related resource / power adjustment configuration, transmission stop indicator), it can disable multi-TRP operation during DAPS HO (e.g., disable SDM-based single-DCI-based multi-TRP by Enhanced TCI States Activation / Deactivation of the UE-specific PDSCH MAC CE). When the CU learns that the UE has successfully accessed the target DU, the UE CONTEXT MODIFICATION REQUEST message can indicate that the UE should stop transmitting data to the source DU, and the source DU will send a DDDS frame to the CU regarding the downlink data that was not successfully transmitted.

[0094] In an embodiment, the CU may send the generated DAPS-related adjustment configuration to the source DU (e.g., by a UE CONTEXT MODIFICATION REQUEST message in block 1006). In an embodiment, the source DU may update / modify the DAPS-related adjustment configuration and send the requested / updated / new adjustment configuration to the CU (e.g., by a UE CONTEXT MODIFICATION RESPONSE message in block 1008).

[0095] In block 1016, the source DU forwards the received RRC Reconfiguration message to the UE. In block 1018, the source DU responds to the CU with a UE CONTEXT MODIFICATION RESPONSE message. In some cases, there may be a downlink data delivery status sent from the source DU to the CU. In block 1020, the random access procedure is performed with the target DU. The target DU sends a Downlink Data Delivery Status frame to notify the CU. Downlink packets (e.g., PDCP PDUs) that were not successfully transmitted by the source DU are sent from the CU to the target DU. In an embodiment, it is up to the CU implementation whether the UE starts transmitting DL User Data to the DU before or after receiving the Downlink Data Delivery Status. In block 1022, the UE responds to the target DU with an RRC Reconfiguration Complete message. In block 1024, the target DU sends a UL RRC MESSAGE TRANSFER message to the CU to convey the received RRC Reconfiguration Complete message. Downlink packets are sent to the UE and / or uplink packets are sent from the UE and forwarded to the CU via the target DU.

[0096] In block 1026, the target CU decides to release the source cell connection. The target CU sends a UE CONTEXT MODIFICATION REQUEST message to the source DU. This UE CONTEXT MODIFICATION REQUEST message includes the generated RRCReconfiguration message, which includes a DAPS-SourceRelease information element (IE) indicating the release of the source cell connection. The UE CONTEXT MODIFICATION REQUEST message may include an indication to the source DU that the DAPS HO is complete or that the source cell is released (e.g., by setting the DAPS HO indication value to "Complete / Released / Stop"). If the indication is received, the target DU may stop using the configuration for power and / or resource adjustment during DAPS HO and / or enable multi-TRP operation during DAPS HO (e.g., by enabling SDM-based single-DCI-based multi-TRP via Enhanced TCI States Activation / Deactivation for the UE-specific PDSCH MAC CE).

[0097] In block 1028, the target DU forwards the received RRCReconfiguration message to the UE. In block 1030, the source DU responds to the CU with a UE CONTEXT MODIFICATION RESPONSE message. In block 1032, the UE responds to the target DU with an RRCReconfigurationComplete message. In block 1034, the target DU sends a UL RRC MESSAGE TRANSFER message to the CU to convey the received RRCReconfigurationComplete message. In block 1036, the CU sends a UE CONTEXT RELEASE COMMAND message to the source DU. In block 1038, the source DU releases the UE context and responds to the CU with a UE CONTEXT RELEASE COMPLETE message. In alternative embodiments, the order of blocks 1024-1038 may be different.

[0098] In an embodiment, the CU may send the generated DAPS-related adjustment configuration to the source DU, e.g., by a UE CONTEXT MODIFICATION REQUEST message at 1006. In an embodiment, the source DU may update / modify the DAPS-related adjustment configuration and send the requested / updated / new adjustment configuration to the CU, e.g., by a UE CONTEXT MODIFICATION RESPONSE message at 1008.

[0099] In one embodiment, the target DU can accept or reject a partial DAPS request (e.g., accept the DAPS request for some DRBs in the DAPS request DRB list and reject the DAPS request for other DRBs in the DAPS request DRB list). In an alternative embodiment, the DAPS-related adjustment configuration received from the CU can be updated / modified. The target DU can send a DAPS HO response indication (e.g., an approved / rejected DAPS request DRB information list) to the CU (e.g., by a UE CONTEXT SETUP RESPONSE message in block 912 or 1012). The target DU can generate a requested / updated / new DAPS-related adjustment configuration (e.g., based on the approved / rejected DAPS request DRB information) and send the configuration to the CU (e.g., by a UE CONTEXT SETUP RESPONSE message in block 912 or 1012). The CU sends the requested / updated / new DAPS-related adjustment configuration to the source DU (e.g., via a UE CONTEXT MODIFICATION REQUEST message in block 914 or 1014). The source DU applies the requested / updated / new DAPS-related adjustment configuration and can use this configuration to perform power and / or resource adjustments during DAPS HO.

[0100] In an embodiment, the target DU may reject the DAPS request (e.g., reject the DAPS request at all DRBs in the DRB list for the DAPS request) and send DAPS HO reject / response information to the CU (e.g., by a UE CONTEXT SETUP RESPONSE message in block 912 or 1012). The CU sends the DAPS reject / response information to the source DU (e.g., by a UE CONTEXT MODIFICATION REQUEST message in block 914 or 1014). If the DAPS reject information is received, the source DU may discard / release the previously generated DAPS-related adjustment configuration.

[0101] 11 shows one embodiment of distributed unit (DU) and target central unit (CU) communication for inter-CU handover (HO). The CU and DU are as described above with respect to FIG. 3 and are an example of a base station. FIG. 11 illustrates communication between a user equipment (UE), a source DU, a target DU, a source CU, and a target CU.

[0102] 11 illustrates that downlink (DL) user data is from the source CU to the source DU or UE, while uplink (UL) user data is from the UE to the source DU or source CU. In block 1102, a Measurement Report message is sent from the UE to the source DU. In block 1104, the source DU sends a UL RRC MESSAGE TRANSFER message to the source CU to convey the received Measurement Report message.

[0103] In block 1106, the source CU sends a UE CONTEXT MODIFICATION REQUEST message to the source DU to inquire about the latest configuration. This message may include a DAPS HO indication to the source DU to indicate that a DAPS HO is prepared, configured, initiated, or requested. The DAPS HO indication may be the HO indication / indicator described above. This indication may include a list of DRB information and / or DAPS HO-specific configuration, such as that a DAPS HO is prepared, configured, initiated, or requested for the associated DRB, or which type of DAPS HO (e.g., inter-frequency DAPS HO, intra-frequency DAPS HO) is prepared, configured, initiated, or requested.

[0104] In block 1108, the source DU responds with a UE CONTEXT MODIFICATION RESPONSE message containing the complete configuration information. If a DAPS HO indication or an inter-frequency DAPS HO indication is received, the source DU can generate DAPS HO-related adjustment configurations (e.g., UL power adjustment parameters or configurations and / or resource adjustment parameters or configurations) and include them in the message. During DAPS HO, the DU uses the generated adjustment configurations for power and / or resource adjustment. If a DAPS HO indication is received, the source DU can disable multi-TRP operation during DAPS HO (e.g., disable SDM-based single DCI-based multi-TRP with Enhanced TCI States Activation / Deactivation for the UE-specific PDSCH MAC CE).

[0105] In block 1110, the source CU sends a Handover Request message to the target CU. This message may include a Handover Preparation Information message. This message may include a DAPS HO indication indicating that a DAPS HO is prepared, configured, initiated, or requested, a list of DRB information for which a DAPS HO is prepared, configured, initiated, or requested, and which type of DAPS HO (e.g., inter-frequency DAPS HO, intra-frequency DAPS HO) is prepared, configured, initiated, or requested, and / or DAPS-specific configurations. This message may include DAPS HO-related adjustment configurations (e.g., UL power adjustment parameters / configurations and / or resource adjustment parameters / configurations).

[0106] In block 1112, the target DU sends a UE CONTEXT SETUP REQUEST message to the target CU to create a UE context and set up one or more data bearers. The UE CONTEXT SETUP REQUEST message may include a HandoverPreparationInformation message. The UE CONTEXT SETUP REQUEST message or the HandoverPreparationInformation message may include DAPS-related adjustment configuration. This adjustment configuration may also be referred to as HO-related configuration. The UE CONTEXT SETUP REQUEST message may include a DAPS HO indication to the target CU to indicate that a DAPS HO is prepared, configured, initiated, or requested. The UE CONTEXT SETUP REQUEST message may also include a list of DRB information and / or DAPS HO-specific configuration regarding whether a DAPS HO is prepared, configured, initiated, or requested for the associated DRBs and / or which type of DAPS HO (e.g., inter-frequency DAPS HO, intra-frequency DAPS HO) is prepared, configured, initiated, or requested.

[0107] In block 1114, the target CU responds to the target DU with a UE CONTEXT SETUP RESPONSE message. If a DAPS HO indication is received, the target CU can disable multi-TRP operation during DAPS HO (e.g., disable SDM-based Single-DCI-based multi-TRP with Enhanced TCI States Activation / Deactivation for UE-specific PDSCH MAC CE). If a DAPS-related adjustment configuration is received, the target CU uses the received adjustment configuration to perform power or resource adjustment during DAPS HO.

[0108] In block 1116, the target CU decides whether to accept the DAPS HO and sends a Handover Request Acknowledge message to the source CU. This message may include a handover command (i.e., an RRC reconfiguration message). This message may include DAPS response information indicating whether the DAPS HO is approved / rejected or whether the DAPS HO is approved / rejected for the associated DRBs (e.g., a list of DRB information indicating whether the DAPS HO is approved / rejected for the associated DRBs). This message may also include requested / updated / new DAPS-related coordination configurations generated / requested by the target CU and / or target DU.

[0109] In block 1118, the source CU sends a UE CONTEXT MODIFICATION REQUEST message to the source DU, including the generated RRC Reconfiguration message and indicating that data transmission for the UE should be stopped. The RRC Reconfiguration message may include the DAPS-related adjustment configuration of the UE. The source DU also sends a Downlink Data Delivery Status frame to notify the CU of the failed downlink data transmission to the UE. In the case of a DAPS handover, the UE CONTEXT MODIFICATION REQUEST message in block 1118 may indicate that data transmission should be stopped only for DRB(s) not undergoing DAPS handover, or may not indicate that data transmission should be stopped at all. Alternatively, the DL RRC Message Transfer procedure may be used to convey the handover command to the UE. Once the source CU recognizes that the UE has successfully accessed the target DU, a UE CONTEXT MODIFICATION REQUEST message is sent to the source DU, indicating that data transmission for the UE should be stopped, and the source DU sends a DDDS frame to the source CU for the downlink data that was not successfully transmitted.

[0110] In block 1120, the source DU forwards the received RRCReconfiguration message to the UE. In block 1122, the source DU responds to the source CU with a UE CONTEXT MODIFICATION RESPONSE message. There may be an optional downlink data delivery status sent from the source DU to the source CU. In block 1124, a random access procedure is performed in the target DU. The target DU sends a Downlink Data Delivery Status frame to notify the source CU. Downlink packets (e.g., PDCP PDUs) that were not successfully transmitted by the source DU are sent from the source CU to the target DU. In an embodiment, it is up to the implementation of the source CU whether the UE starts transmitting DL User Data to the DU before or after receiving the Downlink Data Delivery Status. In block 1126, the UE responds to the target DU with an RRCReconfigurationComplete message. In block 1128, the target DU sends a UL RRC MESSAGE TRANSFER message to the source CU to convey the received RRCReconfigurationComplete message, where downlink packets are sent to the UE and / or uplink packets are sent from the UE and forwarded to the source CU via the target DU.

[0111] In block 1130, in the case of a DAPS handover, the target CU sends a Handover Success message to the source CU to notify it that the UE has successfully accessed the target cell. In response, in block 1132, the source CU sends an SN Status Transfer message to the DAPS-configured DRB for data transfer to the target CU.

[0112] In block 1134, the target CU decides to release the source cell connection. The target CU sends a UE CONTEXT MODIFICATION REQUEST message to the source DU. This UE CONTEXT MODIFICATION REQUEST message includes the generated RRCReconfiguration message, which includes a DAPS-SourceRelease information element (IE) indicating the release of the source cell connection. The UE CONTEXT MODIFICATION REQUEST message may include an indication to the source DU that the DAPS HO is completed or that the source cell is released (e.g., by setting the value of the DAPS HO indication to "Complete / Released / Stop"). If the indication is received, the target DU may stop using DAPS-related adjustment configurations for power and / or resource adjustment during DAPS HO and / or enable multi-TRP operation during DAPS HO (e.g., by enabling SDM-based single-DCI-based multi-TRP via TCI States Activation / Deactivation for the UE-specific PDSCH MAC CE).

[0113] In block 1136, the target DU forwards the received RRC Reconfiguration message to the UE. In block 1138, the source DU responds to the target CU with a UE CONTEXT MODIFICATION RESPONSE message. In block 1140, the UE responds to the target DU with an RRC Reconfiguration Complete message. In block 1142, the target DU sends a UL RRC MESSAGE TRANSFER message to the target CU to convey the received RRC Reconfiguration Complete message. In block 1144, the target CU sends a UE CONTEXT RELEASE COMMAND message to the source CU. In block 1146, the source CU releases the UE context, and in block 1148, receives a response from the source DU that includes a UE CONTEXT RELEASE COMPLETE message. In alternative embodiments, the order of blocks 1132 through 1148 may be different.

[0114] In an embodiment, the source CU may update and / or modify the DAPS-related adjustment configuration, send the requested / updated / new DAPS-related adjustment configuration (e.g., requested / new values ​​of DAPS-related adjustment parameters from the target CU), and send the requested / updated / new adjustment configuration to the source DU (e.g., via a UE CONTEXT MODIFICATION REQUEST message in block 1118 or 1218). If the requested / new / updated adjustment configuration is received, the source DU uses the received configuration to perform power and / or resource adjustment during DAPS HO.

[0115] In an embodiment, the source CU may send the DAPS HO response information received from the target CU and / or the requested / updated / new adjustment configuration to the source DU. This may be sent in a UE CONTEXT MODIFICATION REQUEST message in block 1118 or 1218. If the requested / new / updated adjustment configuration is received, the source DU uses the received configuration to perform power and / or resource adjustment during the DAPS HO. If the DAPS HO response information indicates that the DAPS HO is rejected, the source DU may discard / release any previously generated / received DAPS-related adjustment configurations.

[0116] 12 shows another embodiment of distributed unit (DU) and target central unit (CU) communication for inter-CU handover (HO). The CU and DU are as described above with respect to FIG. 3 and are an example of a base station. FIG. 12 illustrates communication between a user equipment (UE), a source DU, a target DU, a source CU, and a target CU.

[0117] 12 illustrates that downlink (DL) user data is from a source CU to a source DU or UE, and uplink (UL) user data is from a UE to a source DU or source CU. In block 1202, a Measurement Report message is sent from the UE to the source DU. In block 1204, the source DU sends a UL RRC MESSAGE TRANSFER message to the source CU to convey the received Measurement Report message.

[0118] In block 1206, the source CU sends a UE CONTEXT MODIFICATION REQUEST message to the source DU to inquire about the latest configuration. This message may include a DAPS HO indication to the source DU to indicate that a DAPS HO is prepared, configured, initiated, or requested. The DAPS HO indication may be the HO indication / indicator described above. This indication may include a list of DRB information and / or DAPS HO-specific configuration, such as that a DAPS HO is prepared, configured, initiated, or requested for the associated DRB, or which type of DAPS HO (e.g., inter-frequency DAPS HO, intra-frequency DAPS HO) is prepared, configured, initiated, or requested.

[0119] In block 1208, the source DU responds with a UE CONTEXT MODIFICATION RESPONSE message containing complete configuration information. If a DAPS HO indication or an inter-frequency DAPS HO indication is received, the source DU may generate DAPS-related adjustment configurations (e.g., UL power adjustment parameters or configurations and / or resource adjustment parameters or configurations) and include them in the message. During the DAPS HO, the DU uses the generated adjustment configurations for power and / or resource adjustment. If a DAPS HO indication is received, the source DU may disable multi-TRP operation during the DAPS HO (e.g., disable SDM-based single DCI-based multi-TRP with Enhanced TCI States Activation / Deactivation for the UE-specific PDSCH MAC CE).

[0120] In block 1210, the source CU sends a Handover Request message to the target CU. This message may include a Handover Preparation Information message. This message may include a DAPS HO indication indicating that a DAPS HO is prepared, configured, initiated, or requested, a list of DRB information for which a DAPS HO is prepared, configured, initiated, or requested, and which type of DAPS HO (e.g., inter-frequency DAPS HO, intra-frequency DAPS HO) is prepared, configured, initiated, or requested, and / or DAPS-specific configuration. This message may include DAPS-related adjustment configurations (e.g., UL power adjustment parameters / configuration and / or resource adjustment parameters / configuration).

[0121] In block 1212, the target DU sends a UE CONTEXT SETUP REQUEST message to the target CU to create a UE context and set up one or more data bearers. The UE CONTEXT SETUP REQUEST message may include a HandoverPreparationInformation message. The UE CONTEXT SETUP REQUEST message or the HandoverPreparationInformation message may include DAPS-related adjustment configuration. This adjustment configuration may also be referred to as HO-related configuration. The UE CONTEXT SETUP REQUEST message may include a DAPS HO indication to the target CU to indicate that a DAPS HO is prepared, configured, initiated, or requested. The UE CONTEXT SETUP REQUEST message may also include a list of DRB information and / or DAPS HO-specific configuration regarding whether a DAPS HO is prepared, configured, initiated, or requested for the associated DRBs and / or which type of DAPS HO (e.g., inter-frequency DAPS HO, intra-frequency DAPS HO) is prepared, configured, initiated, or requested.

[0122] In block 1214, the target CU responds to the target DU with a UE CONTEXT SETUP RESPONSE message. If a DAPS HO indication is received, the target CU can disable multi-TRP operation during DAPS HO (e.g., disable SDM-based Single-DCI-based multi-TRP with Enhanced TCI States Activation / Deactivation for UE-specific PDSCH MAC CE). If a DAPS-related adjustment configuration is received, the target CU uses the received adjustment configuration to perform power or resource adjustment during DAPS HO.

[0123] In block 1216, the target CU decides whether to accept the DAPS HO and sends a Handover Request Acknowledge message to the source CU. This message may include a handover command (i.e., an RRC reconfiguration message). This message may include DAPS response information indicating whether the DAPS HO is approved / rejected or whether the DAPS HO is approved / rejected for the associated DRBs (e.g., a list of DRB information indicating whether the DAPS HO is approved / rejected for the associated DRBs). This message may also include requested / updated / new DAPS-related coordination configurations generated / requested by the target CU and / or target DU.

[0124] In block 1218, the source CU sends a UE CONTEXT MODIFICATION REQUEST message to the source DU, including the generated RRC Reconfiguration message and indicating to stop data transmission for the UE. The RRC Reconfiguration message may include a DAPS-related adjustment configuration for the UE. The source CU may include a DAPS HO indication and / or a DAPS-related adjustment configuration in the message. If an adjustment configuration is received, the source DU uses the received configuration to perform power and / or resource adjustment during DAPS HO. To notify the CU of a failed downlink data transmission to the UE, the source DU may send a Downlink Data Delivery Status frame. If the source DU receives DAPS-related information (e.g., a DAPS HO indication, a DAPS-related resource / power adjustment configuration, a transmission stop indicator), the source DU may disable multi-TRP operation during DAPS HO (e.g., disable SDM-based single-DCI-based multi-TRP via Enhanced TCI States Activation / Deactivation of the UE-specific PDSCH MAC CE). When the source CU learns that the UE has successfully accessed the target DU, the UE CONTEXT MODIFICATION REQUEST message can indicate that data transmission for the UE should stop being sent to the source DU, and the source DU sends a DDDS frame to the source CU regarding the downlink data that was not successfully transmitted.

[0125] In block 1220, the source DU forwards the received RRCReconfiguration message to the UE. In block 1222, the source DU responds to the source CU with a UE CONTEXT MODIFICATION RESPONSE message. There may be an optional downlink data delivery status sent from the source DU to the source CU. In block 1224, a random access procedure is performed in the target DU. The target DU sends a Downlink Data Delivery Status frame to notify the source CU. Downlink packets (e.g., PDCP PDUs) that were not successfully transmitted by the source DU are sent from the source CU to the target DU. In an embodiment, it is up to the implementation of the source CU to start transmitting DL User Data to the DU before or after receiving the Downlink Data Delivery Status. In block 1226, the UE responds to the target DU with an RRCReconfigurationComplete message. In block 1228, the target DU sends a UL RRC MESSAGE TRANSFER message to the source CU to convey the received RRCReconfigurationComplete message, where downlink packets are sent to the UE and / or uplink packets are sent from the UE and forwarded to the source CU via the target DU.

[0126] In block 1230, for a DAPS handover, the target CU sends a Handover Success message to the source CU to notify the UE that it has successfully accessed the target cell. In response, in block 1232, the source CU sends an SN Status Transfer message to the DAPS-configured DRB to transfer data to the target CU.

[0127] In block 1234, the target CU decides to release the source cell connection. The target CU sends a UE CONTEXT MODIFICATION REQUEST message to the source DU. This UE CONTEXT MODIFICATION REQUEST message includes the generated RRCReconfiguration message, which includes a DAPS-SourceRelease information element (IE) indicating the release of the source cell connection. The UE CONTEXT MODIFICATION REQUEST message may include an indication to the source DU that the DAPS HO is completed or that the source cell is released (e.g., by setting the value of the DAPS HO indication to "Complete / Released / Stop"). If the indication is received, the target DU may stop using DAPS-related adjustment configurations for power and / or resource adjustment during DAPS HO and / or enable multi-TRP operation during DAPS HO (e.g., by enabling SDM-based single-DCI-based multi-TRP via EnhancedTCI States Activation / Deactivation for the UE-specific PDSCH MAC CE).

[0128] In block 1236, the target DU forwards the received RRC Reconfiguration message to the UE. In block 1238, the source DU responds to the target CU with a UE CONTEXT MODIFICATION RESPONSE message. In block 1240, the UE responds to the target DU with an RRC Reconfiguration Complete message. In block 1242, the target DU sends a UL RRC MESSAGE TRANSFER message to the target CU to convey the received RRC Reconfiguration Complete message. In block 1244, the target CU sends a UE CONTEXT RELEASE COMMAND message to the source CU. In block 1246, the source CU releases the UE context, and in block 1248, receives a response from the source DU that includes a UE CONTEXT RELEASE COMPLETE message. In alternative embodiments, the order of blocks 1232 through 1248 may be different.

[0129] The systems and processes described above can be encoded on computer-readable media, such as signal-carrying media or memory, programmed into devices such as one or more integrated circuits or one or more processors, or processed by a controller or computer. The data can be analyzed by a computer system and used to generate a spectrum. When the method is performed by software, the software can reside in a non-volatile or volatile memory that communicates with or interfaces to a storage device, synchronizer, communication interface, or transmitter. The circuit or electronic device is designed to transmit data to another location. The memory can contain an ordered list of executable instructions for performing logical functions. The described logical functions or any system elements can be implemented by optical circuits, digital circuits, source code, analog circuits, analog sources such as analog electrical signals, audio signals, video signals, or combinations thereof. The software can be embodied in any computer-readable or signal-carrying medium for use by or in connection with an instruction-executable system, apparatus, or device. Such a system may include a computer-based system, a system including a processor, or another system capable of selectively fetching instructions from an instruction-executable system, apparatus, or device that is also capable of executing the instructions.

[0130] "Computer-readable medium," "machine-readable medium," "propagating signal" medium, and / or "signal-bearing medium" can include any device that stores, communicates, propagates, or transports software for use by or in connection with an instruction-executable system, apparatus, or device. The machine-readable medium may optionally be, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, device, or propagation medium. A non-exhaustive list of machine-readable media might include electrically connected "electronic equipment" having one or more wires, portable magnetic or optical disks, random access memory "RAM," read-only memory "ROM," volatile memory such as erasable programmable read-only memory (EPROM or flash memory), or optical fiber. Machine-readable media can also include tangible media onto which software is written so that it can be stored electronically as an image or in another format (e.g., by optical scanning) and then compiled and / or interpreted, or otherwise processed. The processed media can then be stored in computer and / or machine memory.

[0131] The illustrations of the embodiments described herein are intended to provide a general understanding of the structures of various embodiments. These illustrations are not intended to serve as a complete description of all elements and features of apparatus and systems that utilize the structures or methods described herein. Many other embodiments will be apparent to those skilled in the art upon reviewing the present disclosure. Other embodiments may be utilized and derived from the present disclosure, and structural and logical substitutions and changes may be made without departing from the scope of the present disclosure. Furthermore, the figures are merely for illustrative purposes and may not be drawn to scale. Certain parts within the illustrations may be exaggerated, while other parts may be minimized. Therefore, the present disclosure and the figures should be considered illustrative and not restrictive.

[0132] One or more embodiments of the present disclosure may be referred to herein, individually and / or collectively, by the term "invention," merely for convenience and without any intention to intentionally limit the scope of the present application to any particular invention or inventive concept. Furthermore, while specific embodiments have been illustrated and described herein, it should be understood that any subsequent device designed to achieve the same or similar purpose may be substituted for the specific embodiment shown. The present disclosure is intended to cover any and all modifications or variations that follow from the various embodiments. Combinations of the above embodiments, as well as other embodiments not specifically described herein, will be apparent to those skilled in the art upon reviewing the description.

[0133] The term "coupled" is defined to mean directly connected to or indirectly connected through one or more intermediate components. Such intermediate components may include both hardware-based and software-based components. The arrangement and type of these components may be varied without departing from the spirit or scope of the claims set forth herein. Additional, different, or fewer components may be provided.

[0134] The subject matter disclosed above should be considered illustrative rather than limiting, and the appended claims are intended to cover all such modifications, extensions, and other embodiments that fall within the true spirit and scope of the invention. Accordingly, to the maximum extent permitted by law, the scope of the invention should be determined by the broadest permissible interpretation of the following claims and their equivalents, and should not be restricted or limited by the foregoing detailed description. While various embodiments of the invention have been described, it will be apparent to those skilled in the art that many more embodiments and implementations are possible within the scope of the invention. Accordingly, the invention should not be limited except in light of the appended claims and their equivalents.

Claims

1. 1. A wireless communication method, comprising: Sending a first request message for handover from a source central unit (CU) to a target CU, the first request message including a handover indication; receiving, by the source CU from the target CU, a response message responding to the first request message, the response message including a handover-related configuration based on the handover indication, the handover being a Dual Active Protocol Stack (DAPS) handover of a user equipment (UE) from a source cell to a target cell, during the DAPS handover, the UE maintaining a connection with the source cell and the target cell, the source cell being within the source CU, and the target cell being within the target CU; sending, by the source CU, to a source distribution unit (DU), a third request message indicating a DAPS handover-related adjustment configuration for performing power adjustment between the source cell and the target cell during the DAPS handover; A method comprising:

2. The method of claim 1 , wherein the first request message is a handover request message and the response message is a handover request acknowledgement message.

3. The handover indication may include: An indication of DAPS handover initiation, or A list of data radio bearer (DRB) information for which a DAPS handover is initiated. The method of claim 1 , comprising at least one of:

4. The method of claim 1 , wherein the first request message further includes the DAPS handover-related adjustment configuration, and the response message includes the handover-related configuration for the target cell.

5. The DAPS handover related adjustment configuration includes: DAPS Handover Related Power Adjustment Parameters The method of claim 4, comprising:

6. 1. A wireless communication method, comprising: receiving, by a target central unit (CU), from a source CU, a first request message for handover including a handover indication; sending, by the target CU to the source CU, a response message responding to the first request message, the response message including a handover-related configuration based on the handover indication, the handover being a Dual Active Protocol Stack (DAPS) handover of a user equipment (UE) from a source cell to a target cell, during the DAPS handover, the UE maintaining a connection with the source cell and the target cell, the source cell being within the source CU, and the target cell being within the target CU; Including, The response message causes the source CU to send a third request message to a source distribution unit (DU), the third request message indicating a DAPS handover-related adjustment configuration for performing power adjustment between the source cell and the target cell during a DAPS handover.

7. The method of claim 6 , wherein the first request message is a handover request message and the response message is a handover request acknowledgement message.

8. The handover indication may include: An indication of DAPS handover initiation, or A list of data radio bearer (DRB) information for which a DAPS handover is initiated. The method of claim 6 , comprising at least one of:

9. The method of claim 6 , wherein the first request message further includes the DAPS handover-related adjustment configuration, and the response message includes the handover-related configuration for the target cell.

10. The DAPS handover related adjustment configuration includes: DAPS Handover Related Power Adjustment Parameters The method of claim 6, comprising:

11. 10. A wireless communication device comprising a processor and a memory, the processor configured to read code from the memory to perform the method of claim 1.

12. A computer-readable storage medium having stored thereon code that, when executed by a processor, causes the processor to perform the method of claim 1.

13. sending a second request message by the source CU to a source distribution unit (DU), the second request message including a DAPS handover status indication to indicate that the DAPS handover has been initiated; The method of claim 1 further comprising:

14. The method of claim 13 , wherein the second request message is a UE context modification message.

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