Conditional Cell Reconfiguration Initiated by Master Node

Abstract

The present disclosure provides for a conditional cell reconfiguration initiated by a master node. In wireless communication, a device may change, add, or handover between providers (e.g., nodes) of network access. This may include a conditional cell addition / change procedure initiated by the master node. Additionally, a continuous cell addition / change may also be performed. The conditional and / or continuous procedures may reduce handover interruption times and improve reliability.

Description

[Technical field]

[0001] Technical Field This document relates generally to wireless communications and, more specifically, to an enhanced conditional cell addition / change procedure initiated by a master node in a mobile device communication system. [Background technology]

[0002] background Wireless communication technologies are moving the world towards an increasingly connected and networked society. Wireless communication relies on efficient network resource management and allocation between user mobile stations and radio access network nodes (including but not limited to radio base stations). New generation networks are expected to achieve high speed, low latency, and ultra-reliable communication capabilities and meet requirements from 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 new generation network services. Summary of the Invention [Means for solving the problem]

[0003] overview This document relates to methods, systems, and devices for change, addition, or handover between providers (e.g., nodes) of network access in a wireless communication environment. This may include a conditional cell addition / change procedure and / or a conditional handover procedure. Additionally, successive cell addition / change or successive handover may also be performed. Conditional mobility extensions may reduce handover interruption times, improve mobility reliability, and / or enable successive conditional handover or conditional cell change / addition.

[0004] In one embodiment, a method for wireless communication includes: transmitting, by a master node ("MN"), to a target secondary node ("SN"), an SN addition request for a SN change from a source SN or an SN addition of the target SN, the request including candidate cell information of the target SN; and receiving a response from the target SN by the MN including candidate cell configurations, the MN transmitting a radio resource control ("RRC") message to a user equipment ("UE") having at least one of the candidate cell configurations and one or more execution conditions of each candidate cell to cause a change or SN addition from the source SN to the target SN based on the candidate cell configuration if one or more execution conditions of the candidate cell associated with the target SN are satisfied. The candidate cell information includes one or more candidate primary secondary cell ("PSCell") identities. The MN provides measurement results of one or more cells in the target SN, the measurement results of each cell including an indicator of whether the cell is a candidate PSCell. The method includes transmitting, by the MN, a candidate cell identity selected by the target SN to the source SN in response to receiving the response including the candidate cell configuration from the target SN. The method includes receiving an RRC Complete message by the MN from the UE to acknowledge receipt of an RRC message with a candidate cell configuration. The method includes transmitting, in response to receiving the RRC Complete message from the UE, a candidate cell identity selected by the target SN by the MN to the source SN. The candidate cell information includes one or more candidate cell identities configured as candidate PSCells. The SN addition request to the target SN includes at least one of an indication indicating a SN change from the target SN back to the source SN after the SN change to one target SN is allowed to be performed, or an indication indicating a SN change from the target SN to another target SN after the SN change to one target SN is allowed to be performed. The candidate cell configuration includes at least one execution condition of the source PSCell or the candidate cell configured as a PSCell candidate.The RRC message includes, for each candidate cell configuration, an indication of whether the candidate cell configuration is maintained after completion of the change from the source SN to the target SN. The RRC message includes an indication of whether the execution condition of each candidate cell or the indicated candidate cell is maintained after completion of the change from the source SN to the target SN. The method includes receiving an RRC completion message by the UE to the MN to notify the execution of the change from the source SN to the target SN, the RRC completion message includes a second RRC completion message sent to the target SN. The second RRC completion message sent to the target SN includes a candidate PSCell identity for which the candidate cell configuration is maintained at the UE side.

[0005] In another embodiment, a method for wireless communication includes receiving a secondary node ("SN") addition request for SN change or SN addition from a source SN by a target secondary node from a master node ("MN"), the request including candidate cell information of the target SN, and the target SN sending a response including a candidate cell configuration to the MN. The MN sends a radio resource control (RRC) message to a user equipment ("UE") having a candidate cell configuration and at least one of one or more execution conditions of each candidate cell to cause a change from the source SN to the target SN based on the candidate cell configuration when one or more execution conditions of the associated candidate cell are satisfied. The candidate cell information includes one or more candidate primary secondary cell ("PSCell") identification information. The MN provides measurement results of one or more cells in the target SN, the measurement results of each cell including an indicator of whether the cell is a candidate PSCell. In response to receiving the response including the candidate cell configuration from the target SN, the MN sends the candidate cell identification information selected by the target SN to the source SN. The MN receives an RRC completion message from the UE to confirm receipt of the RRC message with the candidate cell configuration, and in response to receiving the RRC completion message from the UE, the MN transmits candidate cell identities selected by the target SN to the source SN. The candidate cell information includes one or more candidate cell identities configured as candidate PSCells. The SN addition request to the target SN includes at least one of an indication indicating an SN change from the target SN back to the source SN after the SN change to one target SN is allowed to be performed, or an indication indicating an SN change from the target SN to another target SN after the SN change to one target SN is allowed to be performed. The candidate cell configuration includes at least one execution condition of the source PSCell or the candidate cell configured as a PSCell candidate. The RRC message includes an indication for each candidate cell configuration indicating whether the candidate cell configuration is maintained after the change from the source SN to the target SN is completed.The RRC message includes an indication of whether the execution condition of each candidate cell or the indicated candidate cell is maintained after the change from the source SN to the target SN is completed. The method includes receiving an RRC completion message for notifying the execution of the change from the source SN to the target SN by the target SN from the UE via the MN, where the RRC completion message includes a candidate PSCell identity for which the candidate cell configuration is maintained at the UE side.

[0006] In another embodiment, a method for wireless communication includes receiving, by a user equipment ("UE"), a radio resource control ("RRC") message from a master node ("MN") having a candidate cell configuration and at least one of one or more execution conditions for each of the at least one candidate cell, and performing, by the UE, a change from a source secondary node to a target secondary node based on the candidate cell configuration if the one or more execution conditions for the associated candidate cell are satisfied. The RRC message includes, for each candidate cell configuration, an indication indicating whether the candidate cell configuration is maintained after completion of the change from the source secondary node to the target secondary node. The RRC message includes an indication indicating whether the execution condition for each candidate cell or the indicated candidate cell is maintained after completion of the change from the source secondary node to the target SN. The method includes transmitting, by the UE, an RRC completion message to the MN to notify the performance of the change from the source secondary node to the target secondary node, the RRC completion message including a second RRC completion message transmitted to the target secondary node. The second RRC Complete message sent to the target secondary node includes the candidate PSCell identities for which the candidate cell configuration is maintained on the UE side.

[0007] In one embodiment, a wireless communications device comprises a processor and a memory, the processor configured to read code from the memory and to implement any of the embodiments described above.

[0008] In one embodiment, a computer program product includes a computer readable program medium code stored thereon which, when executed by a processor, causes the processor to implement any of the embodiments described above.

[0009] In some embodiments, there is a wireless communication device comprising a processor and a memory, the processor configured to read code from the memory and perform any method described in any of the embodiments. In some embodiments, a computer program product includes computer readable program medium code stored thereon, the code, when executed by the processor, causes the processor to perform any method described in any of the embodiments. The above and other aspects and implementations thereof are described in more detail in the drawings, specification, and claims. The present invention provides, for example, the following: (Item 1) 1. A method for wireless communication, comprising: Sending, by a master node ("MN"), to a target secondary node ("SN"), a SN addition request for SN change from a source SN or SN addition of the target SN, the request including candidate cell information of the target SN; receiving, by the MN, a response from the target SN, the response including at least one candidate cell configuration; sending, by the MN, to a user equipment ("UE"), a radio resource control ("RRC") message having the at least one candidate cell configuration and the one or more execution conditions for each candidate cell, to cause a change from the source SN to the target SN or an SN addition of the target SN based on the candidate cell configuration when one or more execution conditions for one of the candidate cells from the target SN are satisfied; A method comprising: (Item 2) 2. The method of claim 1, wherein the candidate cell information includes one or more candidate primary secondary cell ("PSCell") identification information. (Item 3) 2. The method of claim 1, wherein the MN provides measurement results for one or more cells in the target SN, the measurement results for each cell including an indicator of whether the cell is a candidate PSCell. (Item 4) 2. The method of claim 1, further comprising: transmitting, by the MN to the source SN, the candidate cell identification information selected by the target SN in response to receiving a response including a candidate cell configuration from the target SN. (Item 5) 2. The method of claim 1, further comprising: receiving an RRC completion message from the UE by the MN to confirm receipt of the RRC message having the candidate cell configuration. (Item 6) 6. The method of claim 5, further comprising: transmitting, by the MN, the candidate cell identity information selected by the target SN to the source SN in response to receiving the RRC completion message from the UE. (Item 7) The method according to item 1, wherein the candidate cell information includes one or more candidate cell identification information configured as a candidate PSCell. (Item 8) The method of claim 1, wherein the SN addition request for a target SN includes at least one of an indication indicating an SN change from the target SN back to the source SN after the SN change is allowed to be performed for one target SN, or an indication indicating an SN change from the target SN to another target SN after the SN change is allowed to be performed for one target SN or after the SN addition for the target SN is allowed to be performed. (Item 9) 9. The method of any one of items 1 to 8, wherein the candidate cell configuration includes the execution condition of at least one of the source PSCell or the candidate cell configured as a PSCell candidate. (Item 10) The method according to item 1, wherein the RRC message includes, for each candidate cell configuration, an indication indicating whether the candidate cell configuration is maintained after completion of the change from the source SN to the target SN or after completion of the SN addition of the target SN. (Item 11) The method according to item 1, wherein the RRC message includes an indication of whether the execution condition of each candidate cell or the indicated candidate cell is maintained after completion of the change from the source SN to the target SN or after completion of the SN addition of the target SN. (Item 12) receiving an RRC completion message from the UE by the MN to notify the execution of the change from the source SN to the target SN or the execution of the SN addition of the target SN, the RRC completion message including a second RRC completion message transmitted to the target SN; 12. The method according to any one of items 1 to 11, further comprising: (Item 13) The method according to item 12, wherein the second RRC completion message sent to the target SN includes the candidate PSCell identification information for which a candidate cell configuration is maintained on the UE side. (Item 14) 1. A method for wireless communication, comprising: receiving, from a master node ("MN"), by a target secondary node ("SN"), a SN addition request for SN change from a source SN or SN addition of the target SN, the request including candidate cell information of the target SN; sending, by the target SN, a response to the MN including at least one candidate cell configuration; Including, The method, wherein the MN sends a radio resource control ("RRC") message to a user equipment ("UE") having at least one candidate cell configuration and one or more execution conditions for each candidate cell, and if the one or more execution conditions for one of the candidate cells from the target SN are satisfied, causes a change from the source SN to the target SN or an SN addition of the target SN based on the candidate cell configuration. (Item 15) 15. The method of claim 14, wherein the candidate cell information includes one or more candidate primary secondary cell ("PSCell") identification information. (Item 16) Item 15. The method of item 14, wherein the MN provides measurement results for one or more cells in the target SN, the measurement results for each cell including an indicator of whether the cell is a candidate PSCell. (Item 17) Item 15. The method of item 14, wherein the MN transmits the candidate cell identification information selected by the target SN to the source SN in response to receiving a response including a candidate cell configuration from the target SN. (Item 18) Item 15. The method of item 14, wherein the MN receives an RRC completion message from the UE to confirm receipt of the RRC message having the candidate cell configuration, and in response to receiving the RRC completion message from the UE, the MN transmits the candidate cell identification information selected by the target SN to the source SN. (Item 19) The method of claim 14, wherein the candidate cell information includes one or more candidate cell identification information configured as a candidate PSCell. (Item 20) Item 15. The method of item 14, wherein the SN addition request for a target SN includes at least one of an indication indicating an SN change from the target SN back to the source SN after the SN change is permitted to be performed for one target SN, or an indication indicating an SN change from the target SN to another target SN after the SN change is permitted to be performed for one target SN or after the SN addition for the target SN is permitted to be performed. (Item 21) 21. The method of any one of items 14 to 20, wherein the candidate cell configuration includes the execution condition of at least one of the source PSCell or the candidate cell configured as a PSCell candidate. (Item 22) The method according to claim 14, wherein the RRC message includes, for each candidate cell configuration, an indication indicating whether the candidate cell configuration is maintained after completion of the change from the source SN to the target SN or after completion of the SN addition of the target SN. (Item 23) Item 15. The method according to item 14, wherein the RRC message includes an indication of whether the execution condition of each candidate cell or the indicated candidate cell is maintained after completion of the change from the source SN to the target SN or after completion of the SN addition of the target SN. (Item 24) receiving an RRC completion message from the UE via the MN to notify the target SN of the change from the source SN to the target SN or the addition of the SN to the target SN, the RRC completion message including the candidate PSCell identity information for which a candidate cell configuration is maintained at the UE side; 15. The method of claim 14, further comprising: (Item 25) 1. A method for wireless communication, comprising: receiving, by a user equipment ("UE"), a radio resource control ("RRC") message from a master node ("MN") having at least one candidate cell configuration and one or more execution conditions for each of the at least one candidate cell; When one or more execution conditions for one of the candidate cells from the target SN are satisfied, performing, by the UE, a change from a source secondary node to a target secondary node or a secondary node addition for the target secondary node based on the candidate cell configuration; A method comprising: (Item 26) 26. The method of claim 25, wherein the RRC message includes, for each candidate cell configuration, an indication of whether the candidate cell configuration is maintained after completion of the change from the source secondary node to the target secondary node or whether the candidate cell configuration is maintained after completion of the secondary node addition of the target secondary node. (Item 27) 26. The method of claim 25, wherein the RRC message includes an indication of whether the execution condition of each candidate cell or the indicated candidate cell is maintained after completion of the change from the source secondary node to the target secondary node or after completion of the secondary node addition of the target secondary node. (Item 28) sending an RRC completion message by the UE to the MN to notify the MN of the change from the source secondary node to the target secondary node or the addition of the secondary node to the target secondary node, the RRC completion message including a second RRC completion message sent to the target secondary node; 28. The method according to any one of items 25 to 27, further comprising: (Item 29) 29. The method of claim 28, wherein the second RRC completion message sent to the target secondary node includes the candidate PSCell identification information for which a candidate cell configuration is maintained on the UE side. (Item 30) 30. A wireless communication device comprising a processor and a memory, the processor configured to read a code from the memory and to perform a method according to any one of items 1 to 29. (Item 31) 30. A computer program product having stored thereon a computer readable program medium code, the code being configured to, when executed by a processor, cause the processor to perform a method according to any one of items 1 to 29. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 illustrates an exemplary base station.

[0011] [Diagram 2] FIG. 2 illustrates an exemplary random access (RA) messaging environment.

[0012] [Figure 3A] FIG. 3A illustrates an embodiment of a user equipment (UE) in communication with a node.

[0013] [Figure 3B] FIG. 3B illustrates an embodiment of a user equipment (UE) for changing a secondary node.

[0014] [Figure 4A] FIG. 4A illustrates an embodiment of a secondary node (SN) initiated cell change procedure.

[0015] [Figure 4B] FIG. 4B illustrates additional features of the secondary node (SN) initiated cell change procedure illustrated in FIG. 4A.

[0016] [Figure 5A] FIG. 5A illustrates an embodiment of a master node (MN) initiated cell change procedure.

[0017] [Figure 5B] FIG. 5B illustrates additional features of the master node (MN) initiated cell change procedure illustrated in FIG. 5A.

[0018] [Figure 6A] FIG. 6A illustrates an embodiment of continuous conditional handover (CHO).

[0019] [Figure 6B] FIG. 6B illustrates additional features of the continuous conditional handover (CHO) illustrated in FIG. 6A.

[0020] [Figure 7A] FIG. 7A illustrates an embodiment of a continuous cell change / add procedure.

[0021] [Figure 7B] FIG. 7B illustrates an additional feature of the successive cell change / add procedure illustrated in FIG. 7A. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Detailed Description The present disclosure will now be described in detail with reference to the accompanying drawings, which form a part hereof, and which show, by way of illustration, specific embodiments of the present disclosure. It should be noted, however, that the present disclosure may be embodied in a variety of different forms, and thus, the subject matter embraced or claimed is not intended to be construed as being limited to any of the embodiments described below.

[0023] Throughout this specification and the claims, terms may have subtle meanings that are suggested or implied in the context beyond the explicitly stated meaning. Similarly, the phrases "in one embodiment" or "in some embodiments" used herein do not necessarily refer to the same embodiment, and the phrases "in another embodiment" or "in other embodiments" used herein do not necessarily refer to different embodiments. The phrases "in one implementation" or "in some implementations" used herein do not necessarily refer to the same implementation, and the phrases "in another implementation" or "in other implementations" used herein do not necessarily refer to different implementations. For example, the claimed subject matter is intended to include a combination of example embodiments or implementations in whole or in part.

[0024] Generally, terms may be understood at least in part from their use in context. For example, terms such as "and," "or," or "and / or" as used herein may include various meanings that may depend, at least in part, on the context in which such terms are used. Typically, "or" when used to relate a list such as A, B, or C is intended to mean A, B, and C, which are used herein in an inclusive sense, as well as A, B, or C, which are used herein in an exclusive sense. Additionally, terms such as "one or more" or "at least one" as used herein may be used to describe any feature, structure, or characteristic in a singular sense, or may 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," or "the" may be understood to convey the use of the singular or to convey the use of the plural, depending, at least in part, on the context. Additionally, terms such as "based on" or "determined by" may be understood not to be intended to convey an exclusive set of factors, but instead may allow for the existence of additional factors not necessarily explicitly described, depending, at least in part, on the context.

[0025] Radio Resource Control ("RRC") is a protocol layer between the UE and the base station (network layer) at the IP level. There may be various Radio Resource Control (RRC) states, such as RRC_CONNECTED, RRC_INACTIVE, and RRC_IDLE. RRC messages are transmitted via the Packet Data Convergence Protocol ("PDCP"). As previously mentioned, the UE may transmit data via a Random Access Channel ("RACH") protocol scheme or a Configuration Grant ("CG") scheme. CG may be used to reduce waste of periodically allocated resources by allowing multiple devices to share the periodic resources. A base station or node may allocate CG resources to eliminate packet transmission delays and increase utilization of the allocated periodic radio resources. The CG scheme is only one example of a protocol scheme for communication, and other examples are possible, including but not limited to RACH. The wireless communication described herein may be by radio access.

[0026] As described below with respect to Figures 1-3B, a network provider may include multiple network nodes (i.e., base stations) for providing network access to user equipment ("UE") devices. In some embodiments, the network nodes are referred to as base stations. There may be a master node ("MN") and one or more secondary nodes ("SN"). The MN may include a master cell group ("MCG") and the SN may include a secondary cell group ("SCG" respectively). The MCG is a group of cells provided by the master node ("MN") and the SCG is a group of cells provided by the secondary node ("SN"). The MCG may include a primary cell ("PCell") and one or more secondary cells ("SCell"). The SCG may include a primary secondary cell ("PSCell") and one or more secondary cells ("SCell"). Each primary cell may be connected with multiple secondary cells. The primary cell (PCell, PSCell) is the master cell of the respective group (MCG, SCG respectively) and may initiate initial access. The primary cell may be used for signaling and may be called a special cell (spCell), where spCell=PCell+PSCell.

[0027] A user equipment ("UE") device may move between nodes or cells, in which case handover or change / add operations may occur to improve network reliability for the moving UE. The move may be from a source secondary node to a target secondary node. There may be several potential target secondary nodes, called candidates. Similarly, a move between cells may also include several target cells that are potential candidate cells. Conditional Handover ("CHO") and Conditional PSCell Addition / Change ("CPAC") are described below. CPAC may include Conditional PSCell Change ("CPC") and / or Conditional PSCell Addition ("CPA").

[0028] Conditional Handover ("CHO") can reduce handover interruption time and improve mobility reliability. CHO is a handover executed by a UE when one or more execution conditions are met. The UE can evaluate the execution conditions when it receives a CHO configuration and can stop evaluating the execution conditions when a handover is triggered. The CHO configuration can include a candidate PCell configuration generated by a candidate target node and the corresponding execution conditions for that candidate cell.

[0029] Conditional PSCell Addition / Modification ("CPAC") may include a UE having a network configuration to initiate access to a candidate PSCell to consider whether the PSCell is suitable for SN addition or either SN change, including intra-SN change. This consideration may be based on configured conditions. UEs in a wireless network may operate in dual connectivity ("DC"), including intra-E-UTRA DC or multi-radio DC ("MR-DC"). In an example of intra-E-UTRA DC, both the MN and SN provide E-UTRA access. In an example of MR-DC, one node provides New Radio ("NR") access and the other node provides either E-UTRA or NR access.

[0030] In CPAC / CHO, some inter-node interactions may enable transfer of proposed candidate cell information, execution conditions, and / or accepted candidate cell information between the MN, source SN, and target SN. Due to high frequency deployment and smaller cell sizes, PCell / PSCell changes may occur frequently in NR. Thus, continuous handover or PSCell changes may be required to reduce handover interruption time and improve mobility reliability. As described below, conditional mobility extensions may reduce handover interruption time, improve mobility reliability, and / or enable continuous CHO / CPAC.

[0031] FIG. 1 illustrates an exemplary base station 102. A base station may also be referred to as a radio network node, and may be a network node (e.g., a master node ("MN"), a secondary node ("SN"), and a source / target node) illustrated in FIGS. 3A-7B. The base station 102 may be further identified as a nodeB (NB, e.g., eNB or gNB) in the context of mobile communications. The exemplary base station may include wireless Tx / Rx circuitry 113 for transmitting to and receiving 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 interconnects, 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 operations 128 and control parameters 130. The operations 128 may include instructions for execution by one or more of the processors 124 to support the functionality of the base station. For example, these operations may process random access transmission requests from multiple UEs. The control parameters 130 may include parameters that support the execution of the operations 128. For example, the control parameters may include network protocol settings, random access message formatting rules, bandwidth parameters, radio frequency mapping assignments, and / or other parameters.

[0033] 2 illustrates an example random access messaging environment 200. In the random access messaging environment, a UE 104 may 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 a SIM 1202. An electrical and physical interface 206 connects the SIM 1202 to the rest of the user equipment hardware, for example, via a system bus 210.

[0034] The mobile device 200 includes a communication 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, for example, by one or more systems on a chip (SoC), application specific integrated circuits (ASICs), 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 that regard, the system logic 214 may include logic to facilitate music and video decoding and playback, such as MP3, MP4, MPEG, AVI, FLAC, AC3, or WAV decoding and playback; running applications; accepting user input; storing and retrieving application data; establishing, maintaining, and terminating data connections for cellular phone calls or Internet connections, as an example; establishing, maintaining, and terminating wireless network connections, Bluetooth connections, or other connections; and displaying related information on the user interface 218. The 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 may include microphones, video and still image cameras, temperature sensors, vibration sensors, rotation and orientation sensors, headset and microphone input / output jacks, Universal Serial Bus (USB) connectors, memory card slots, radiation sensors (e.g., IR sensors), and other types of inputs.

[0035] The system logic 214 may include one or more processors 216 and a memory 220. The memory 220 stores, for example, control instructions 222 that the processor 216 executes to perform desired functions for the UE 104. Control parameters 224 provide and specify configuration and operation options for the control instructions 222. The memory 220 may also store any BT, WiFi, 3G, 4G, 5G, or other data 226 that the UE 104 transmits or receives via the communication interface 212. In various implementations, 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 may include one or more transceivers. The transceiver may be a wireless transceiver that includes 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 (in the case of some devices) over a physical (e.g., wired) medium.

[0037] The transmitted and received signals may conform to any of a diverse array of formats, protocols, modulations (e.g., QPSK, 16-QAM, 64-QAM, or 256-QAM), frequency channels, bit rates, and coding. As one specific example, the communication interface 212 may include a transceiver supporting transmission and reception under 2G, 3G, BT, WiFi, Universal Mobile Telecommunications System (UMTS), High Speed ​​Packet Access (HSPA)+, 4G / Long Term Evolution (LTE) standards. However, the techniques described below are applicable to other wireless communication technologies, whether arising from 3rd Generation Partnership Project (3GPP), GSM Association, 3GPP2, IEEE, or other partnerships or standards bodies.

[0038] Multiple RAN nodes of the same or different Radio Access Technology ("RAT") (e.g., eNB, gNB) may be located on the same or different frequency carriers in a particular geographical area, and they may interwork with each other via dual connectivity operation to provide joint communication services to the same target UE. A Multi-RAT Dual Connectivity ("MR-DC") architecture may have a non-co-located Master Node ("MN") and Secondary Node ("SN"). An embodiment is shown in Figures 3A-3B. The Access Mobility Function ("AMF") and Session Management Function ("SMF") may be 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") may be a Next Generation-Control Plane ("NG-C") / MN interface. The signaling connection between the MN and the SN may be an Xn Control Plane ("Xn-C") interface. The signaling connection between the MN and the UE is the Uu Control Plane ("UU-C") RRC interface. All these connections govern the configuration and operation of the MR-DC. The user plane connection between the User Plane Function ("UPF") and the MN may be the NG-U(MN) interface instance.

[0039] FIG. 3A illustrates an embodiment of a user equipment (UE) communicating with nodes. A master node ("MN") generates a first cell, cell1. There are two secondary nodes ("SN"), labeled SN1 and SN2. The cell for SN1 is cell2, and the cell for SN2 is cell3. Each of the three network nodes provides a corresponding cell for the user equipment ("UE") to connect to the network. A UE 302 is shown at a first time T1 within range of the MN and SN1. As illustrated, the UE 302 is operating in a dual connection ("DC") between the MN and SN1.

[0040] Figure 3B illustrates an embodiment of a user equipment (UE) changing secondary nodes. The UE 304 is shown moving from time T1 (which was in cell 2) to being in cell 3 at time T2, where it is now in cell 3 or MN+SN2. As the UE moves from 302 to 304 as shown in Figures 3A-3B, the SN changes from SN1 to SN2. As will be described below, the SN change can be initiated by either the MN or the source SN. In Figure 3B, SN1 is the source SN and SN2 is the target SN.

[0041] To reduce the interruption time during SN change or SN addition and improve mobility reliability, a Conditional PSCell Addition / Modification ("CPAC") is described. CPAC may include a PSCell addition / modification that is performed by the UE when one or more execution conditions are met. The UE evaluates the one or more execution conditions upon receiving a CPAC configuration and stops evaluating the one or more execution conditions when a PSCell addition / modification is triggered. The CPAC configuration may include a candidate PSCell configuration generated by a candidate SN and the corresponding one or more execution conditions of the candidate PSCell. The CPAC procedure may be initiated by the SN as shown in Figures 4A-4B or may be initiated by the MN as shown in Figures 5A-5B. In other embodiments, the CPAC procedure may be classified as CPAC with MN involvement or CPAC without MN involvement in case there is intra-SN CPAC without MN involvement. SN Initiated CPAC Procedure

[0042] FIG. 4A illustrates an embodiment of a cell change procedure initiated by a secondary node (SN). FIG. 4A illustrates communication between a user equipment ("UE"), a master node ("MN"), a source secondary node ("S-SN"), a first target secondary node ("T-SN1"), and a second target secondary node ("T-SN2"). The source secondary node S-SN initiates a conditional SN change procedure by sending an SN change request message 402 to the MN. In this message, the source SN may include the proposed candidate PSCell identity, the corresponding execution condition (or conditions), measurement results related to the target SN, and / or a CPAC indication to indicate that it is a condition-based procedure. The source SN may also include an updated source SCG configuration (e.g., measurement configuration) to the MN.

[0043] The S-SN to MN change request message 402 may include a list of proposed CPAC candidate cells. The list of candidate cells may include candidate cell IDs, CGIs, and / or PCI+ frequencies. The list of candidate cells may further include a list of execution conditions. The list of execution conditions may include that each execution condition is linked to a corresponding candidate cell (e.g., candidate cell IDs, CGIs, PCI+ frequencies) and / or may include execution conditions where the input order of each item in the execution conditions list is the same as the input order of each item in the candidate cell list. The S-SN to MN change request message 402 may include an indicator included in the measurement result list provided by the source SN (i.e., candidateCellInfoListSN) to indicate whether the indicated cell is proposed as a CPAC candidate cell. The list may include a list of cell identifiers and corresponding measurements of that list. The items included in the S-SN to MN change request message 402 may be transferred by including each item as one information element (IE) in an Xn / X2 message, e.g., an SN(SgNB) change request message. Alternatively, the items included in the S-SN to MN modification request message 402 may be forwarded by including each item in an RRC message, e.g., a CG-Config message, which may be included as one IE in an Xn / X2 message, e.g., an SN(SgNB) modification request message.

[0044] The MN sends an SN Addition Request message 404 to the target secondary node T-SN1. In this message, the MN may include candidate PSCell identities proposed by the source SN (recommended candidates), measurement results related to the target SN, and / or a CPAC indication indicating that this is a condition-based procedure. T-SN1 responds to the SN Addition Request 404 with an SN Addition Request Acknowledgement message 406 to the MN. The Acknowledgement message 406 includes the candidate PSCell configuration and / or the selected candidate PSCell identities.

[0045] The MN sends an SN change confirmation message 408 (or other Xn / X2 message) to the source secondary node S-SN. The change confirmation message 408 includes the candidate PSCell identities accepted / rejected by the target secondary node T-SN1. After receiving the change confirmation message 408, the S-SN may initiate an SN change procedure to update the S-SN configuration (e.g., measurement configuration, execution conditions).

[0046] The MN sends a reconfiguration message 410 to the UE. The reconfiguration message 410 may be an RRCReconfiguration message including a CPAC configuration for the UE. The CPAC configuration may include at least the candidate PSCell configurations generated by the T-SN1 and the corresponding execution conditions generated by the S-SN. The UE responds to the reconfiguration message 410 to the MN to acknowledge receipt of the reconfiguration message with a reconfiguration complete message 412. The reconfiguration complete message 412 may be an RRCReconfigurationComplete message including an embedded RRCReconfigurationComplete message to the S-SN. The remaining communications of the SN initiated change procedure are shown in FIG. 4B.

[0047] Figure 4B illustrates an additional feature of the secondary node (SN) initiated cell change procedure shown in Figure 4A: After the reconfiguration complete message 412, the MN sends an SN reconfiguration complete message 414 to the source SN if the SN reconfiguration complete message 410 was received.

[0048] The UE maintains a connection with the S-SN and begins evaluating one or more execution conditions 416. If at least one execution condition of the candidate PSCell is satisfied, the UE may select the associated cell as a target PSCell and trigger the execution of CPAC to access the target SN T-SN1. Upon execution of CPAC, the UE sends a reconfiguration complete message 418 to the MN. The reconfiguration complete message 418 may be an RRCReconfigurationComplete message to the MN that includes an embedded RRCReconfigurationComplete to the target SN. In some embodiments, the MN may forward an SN reconfiguration complete message 420 to the target SN T-SN1.

[0049] The UE performs a random access procedure 422 towards the target PSCell of the target SN T-SN1. The order in which the UE sends the RRCReconfigurationComplete message 418 and performs the random access procedure 422 towards the target SN may be changed. The MN initiates an SN release procedure 424 towards the source SN S-SN to release the S-SN resources. The MN initiates an SN release procedure 426 towards another candidate SN (T-SN2) to release the reserved candidate (T-SN2) PSCell resources.

[0050] In some embodiments, since the MN informs the S-SN of the accepted / configured / rejected candidate PSCell identities via the SN reconfiguration complete message (or other Xn / X2 message) as part of the SN reconfiguration complete message 420, the MN shall not send a change confirmation message 408 to the S-SN after the SN addition procedure.

[0051] Referring again to the S-SN to MN change request message 402, which may include a list of proposed CPAC candidate cells, a list of execution conditions, and / or an indication of whether the cell is a CPAC candidate. The S-SN includes one list for candidate cell identifiers (e.g., candidateCellListCPCSSN), one list for execution conditions (e.g., condExecutionCondListCPCSN), and one list for measurements (i.e., candidateCellInfoListSN) in the CG-Config message to the MN. The order of entries in the execution condition list (e.g., condExecutionCondListCPCSN) may be the same as the order of entries in the candidate cell identifier list (e.g., candidateCellInfoListCPCSSN). The following is an example of code for this embodiment: [ka]

[0052] The S-SN includes one list for candidate cell identifiers and corresponding execution conditions (e.g., candidateCellListCPCSN) and one list for measurements in the CG-Config message for the MN (i.e., candidateCellInfoListSN). It may combine the execution conditions and the candidate cell list, but does not include the indicator. The following is an example of code for this embodiment: [ka]

[0053] The S-SN includes one list for candidate cell identifiers and corresponding execution conditions (e.g., candidateCellListCPCSN) in the MN and adds an indicator to the existing measurement list (i.e., candidateCellInfoListSN) in the CG-Config message to indicate whether the cell is a CPC candidate cell or not. In other words, it combines the candidate cell list and the execution conditions. In one example, the list of candidate cell identifiers and the corresponding execution conditions (e.g., candidateCellListCPCSN) can be the same as those shown above. An example of an indicator in the measurement list is shown below: [ka]

[0054] If multiple candidate SNs are prepared by one SN-initiated CPAC procedure, the SN change request message 402 may include a list of candidate SN information (e.g., a list of candidate SN IDs, or / and a list of candidate PSCell information for each candidate SN). There are several options for forwarding the proposed candidate SN information to the MN, including the S-SN sending a list of CG-Config messages to the MN, where each CG-Config message is linked with a candidate SN ID. In another option, the S-SN sends one CG-Config message to the MN, which includes multiple candidate cell lists, execution condition lists, or / and measurement result lists, where each list is linked with a corresponding candidate SN ID.

[0055] Referring back to FIG. 4A, when the MN sends a SN Addition Request message 404 to the target secondary node T-SN1, this message may include candidate PSCell identities (recommended candidates) proposed by the source SN, measurement results related to the target SN and / or CPAC indication to indicate that this is a condition-based procedure. There may be further inter-node interactions between the MN and the T-SN1. The SN Addition Request message 404 includes at least a list of candidate cells (e.g., candidate cell IDs, CGI, frequency+PCI) proposed by the S-SN. This list may be forwarded from the MN to the T-SN1 by including an item as an IE in an Xn / X2 message, e.g., an SN(SgNB) Addition Request message, or by including an item in an RRC message, e.g., a CG-ConfigInfo message. The RRC message may be included as an IE in an Xn / X2 message, e.g., an SN(SgNB) Addition Request message.

[0056] The MN may include one list of candidate cell identifiers (e.g., candidateCellListCPCSN) in a CG-ConfigInfo message to the candidate SN. In one example, it is: [ka] MN Initiated CPAC Procedure

[0057] FIG. 5A illustrates an embodiment of a cell change or addition procedure initiated by a master node (MN). While FIG. 4A-4B illustrated an SN-initiated CPAC procedure, FIG. 5A-5B illustrates an MN-initiated CPAC. FIG. 5A-5B illustrates communication between a user equipment ("UE"), a master node ("MN"), a source secondary node ("S-SN"), a first target secondary node ("T-SN1"), and a second target secondary node ("T-SN2"). The master node MN initiates a conditional SN addition / change procedure by sending an SN addition request message 502 to the target SN T-SN1. This message may include proposed candidate PSCell identities, a corresponding execution condition (or conditions), measurement results related to the target SN, and / or a CPAC indication indicating that it is a condition-based procedure.

[0058] The SN Addition Request message 502 from the MN to the T-SN1 may include a list of proposed CPAC candidate cells proposed by the MN. The list of candidate cells may include candidate cell IDs, CGIs, and / or PCI+ frequencies. The SN Addition Request message 502 may include an indicator included in a measurement result list provided by the MN (i.e., candidateCellInfoListMN) to indicate whether the indicated cell is proposed as a CPAC candidate cell. The list may include a list of cell identifiers and corresponding measurements of the list. Each item included in the SN Addition Request message 502 from the MN may be forwarded by including each item as one information element (IE) in an Xn / X2 message, e.g., an SN(SgNB) Addition Request message. Alternatively, the items included in the SN Addition Request message 502 from the MN may be forwarded by including each item in an RRC message, e.g., a CG-ConfigInfo message. The RRC message may be included as one IE in an Xn / X2 message, e.g., an SN(SgNB) Addition Request message.

[0059] The target SN T-SN1 responds to the MN with a SN Addition Request Acknowledgement 504. The SN Addition Request Acknowledgement 504 includes the candidate PSCell configuration and / or the selected candidate PSCell identity. The MN determines and / or configures the execution conditions 506 of the candidate PSCell. The MN sends an Xn / X2 message 508 (e.g., an Xn-U Address Indication message or other / new Xn / X2 message) to the source SN. The message 508 may include the candidate PSCell identity accepted / configured by T-SN1, e.g., candidate cell ID, CGI, and / or PCI+ frequency.

[0060] The MN sends a cell reconfiguration message 510 to the UE. The cell reconfiguration message 510 may be an RRC Reconfigration message including a CPAC configuration to the UE. The CPAC configuration may include at least the candidate PSCell configurations generated by the T-SN1 and the corresponding execution conditions generated by the MN. The UE responds with a reconfiguration complete message 512. The reconfiguration complete message 512 may include an RRC Reconfiguration Complete message to the MN to acknowledge receipt of the cell reconfiguration message 510 or the RRC Reconfiguration message. The remaining communications for the MN initiated modification / add procedure are shown in FIG. 5B.

[0061] FIG. 5B illustrates additional features of the master node (MN) initiated cell addition / change procedure illustrated in FIG. 5A. After the UE to MN reconfiguration complete message 512, the MN may send an Xn / X2 message 514 (e.g., Xn-U address indication message or new / other Xn / X2 message) to the source SN including the candidate PSCell identities accepted by the target SN. Messages 508 and 514 may be optional. In one embodiment, only one of the two messages is sent. In some embodiments, the MN may not send a message to the source SN after the SN addition procedure, and the MN shall inform the source SN of the accepted / configured candidate PSCell identities after receiving the reconfiguration complete message 512 from the UE. In some embodiments, the MN shall inform the source SN of the accepted / configured candidate PSCell identities after the SN addition procedure, and the MN may not send a message to the source SN after receiving the reconfiguration complete message 512 from the UE.

[0062] The UE maintains the connection with the source SN and starts evaluating the execution conditions 516. If at least one execution condition of the candidate PSCell is met, the UE selects the associated cell as the target PSCell and triggers the execution of CPAC to access the T-SN1. Upon execution of CPAC, the UE sends a reconfiguration complete message 518 to the MN with an embedded RRCReconfigurationComplete to the target SN. The MN forwards a reconfiguration complete message 520 to the T-SN1. The UE performs a random access procedure 522 towards the target PSCell of the T-SN1. The order in which the UE sends the reconfiguration complete message 518 and performs the random access procedure 522 towards the target SN may be changed. The MN initiates an SN release procedure 524 towards the source SN (S-SN) to release the S-SN resources. The MN initiates an SN release procedure 526 towards other candidate SNs (e.g., T-SN2) to release the reserved candidate PSCell resources.

[0063] For the add procedure, messages related to the source SN ("S-SN") are not required. In other words, for the add procedure, blocks in Figures 5A-5B that can be ignored or skipped include blocks 508, 514, 520, and 524.

[0064] Referring again to the SN Addition Request message 502 from the MN, which may include a list of proposed CPAC candidate cells and / or an indication of whether a cell is a CPAC candidate. The MN includes one list of candidate cell identifiers (e.g., candidateCellListCPCSN) in the CG-Config message to the MN. The following is an example of code for this embodiment: [ka]

[0065] The MN adds an indicator (e.g., cpcCandidate) in the existing measurement list provided by the MN (i.e., candidateCellInfoListMN) to the CG-ConfigInfo message to indicate whether the cell is a CPC candidate cell. The following is an example of code for this embodiment: [ka]

[0066] The MN sends an Xn / X2 message (e.g., Data Forwarding Address Indication message, Xn-U Address Indication message, or other / new Xn / X2 message) to the target SN in response to at least one of the following: 1) upon receiving an SN Addition Acknowledgement message 504 from the T-SN1, or 2) upon receiving a Reconfiguration Complete message 512 from the UE (to acknowledge receipt of the CPAC configuration). The message may include at least one of: 1) a list of candidate PSCells (e.g., candidate cell IDs, CGI, frequency+PCI) accepted / configured by the T-SN1, 2) an indication that a MN-initiated CPAC or CPAC is configured or that the procedure involves a MN-initiated CPAC or CPAC (e.g., a "CPAC indicator"), or 3) data forwarding information T-SN1, e.g., data forwarding address information, which may be provided per candidate SN or per candidate PSCell. The information may be forwarded from the MN to the T-SN1 by including the item as an IE in an Xn / X2 message, e.g., Data Forwarding Address Indication message, Xn-U Address Indication message, or other / new Xn / X2 message, or by including the item in an RRC message, e.g., a CG-ConfigInfo message. The RRC message may be included in the Xn / X2 message as an IE. Upon receiving the configured candidate PSCell information from the MN, the source SN may perform early data forwarding for SN terminated bearers along with sending an EARLY STATUS TRANSFER message to the MN, or the source SN may send an updated SCG configuration to the MN if the source SN decides to modify the source SN configuration, regardless of whether SRB3 is configured or not.

[0067] The MN may include one list of candidate cell identifiers (e.g., candidateCellListCPCSN) in a CG-ConfigInfo message to the source SN. In one example, it is: [ka]

[0068] 4A-4B describe SN-initiated CPAC, while FIG. 5A-5B describe MN-initiated CPAC. To prevent conflicts between initiation of CPAC, inter-node coordination between MN and S-SN may be required to prevent both SN-initiated and MN-initiated CPAC. There are several embodiments to prevent this conflict.

[0069] In a first embodiment, the MN informs the T-SN1 when the MN-initiated CPC is configured, e.g., upon receipt of an SN addition request acknowledgement from the T-SN1 or upon receipt of a reconfiguration complete message from the UE (to confirm receipt of the CPAC configuration). The MN sends an indication to inform the SN about the MN-initiated CPAC via Xn / X2 signaling. This indication may include 1) a list of candidate PSCells configured by the MN-initiated CPC, 2) an indicator indicating a configured MN-initiated CPAC, e.g., setting an "MN-initiated CPAC" indicator as true, or 3) an indicator indicating a SN-initiated CPAC that cannot be configured, e.g., setting an "SN-initiated CPAC" indicator as false. After receiving the indication, the SN shall not configure the SN-initiated CPAC. If the SN-initiated CPAC is configured, the SN shall release the prepared SN-initiated CPAC.

[0070] In a second embodiment, the S-SN notifies the MN when an SN-initiated CPAC is configured, e.g., upon receiving a reconfiguration complete message from the UE (to confirm receipt of the CPAC configuration). In this embodiment, the SN sends an indication via Xn / X2 signaling to inform the MN about the SN-initiated intra-SN CPC. This indication may include 1) a list of candidate PSCells configured via the SN-initiated intra-SN CPC, 2) an indicator indicating a configured SN-initiated intra-SN CPC, e.g., setting "SN-initiated intra-SN CPC indicator" as true, or 3) an indicator indicating a MN-initiated CPC that cannot be configured, e.g., setting "MN-initiated CPC" as false. After receiving the indication, the MN shall not configure the MN-initiated CPC. If the MN-initiated CPC is configured, the MN shall release the prepared MN-initiated CPC.

[0071] In a third embodiment, the MN indicates to the S-SN that the maximum number of candidate PSCells that can be configured by SN-initiated CPAC is set to zero. In this embodiment, the SN cannot subsequently initiate a CPAC procedure.

[0072] In a fourth embodiment, the MN can directly release the candidate PSCell configured by the SN-initiated CPC, for example, can send condReconfigToRemoveList to the UE to delete the stored PSCell configuration. The MN notifies the S-SN of the release of the candidate PSCell configured by the SN-initiated CPC via an Xn / X2 message. In this embodiment, the MN sends a message to the UE to release the candidate PSCell.

[0073] The indication in any of the above-mentioned embodiments can be transferred by including the indication as an IE in an Xn / X2 message, such as an SN(SgNB)ModifyRequest or SN(SgNB)ModifyRequest message, or by including the indication in an RRC message, such as a CG-ConfigInfo or CG-Config message. The RRC message may be included in the Xn / X2 message as an IE. Continuous conditional reconstruction

[0074] Conditional Handover ("CHO") and Conditional PSCell Addition / Modification ("CPAC") may be collectively referred to as conditional reconfiguration. Conditional reconfiguration may be continuous as described below. The network may indicate whether continuous CHO / CPAC is allowed. For CHO, the network may point to the source node, and for CPAC, the network may point to the master node ("MN") or source secondary node ("S-SN"). That continuous CHO / CPAC is possible may be indicated in any of the following embodiments.

[0075] In a first embodiment, the indication process for the network may include the network sending an indication to the UE indicating whether successive CHO / CPAC is allowed (e.g., a "successive CHO / CPAC" or "successive conditional reconfiguration" indicator), in other words, whether CHO / CPAC is allowed from the target PCell / PSCell / node to another target PCell / PSCell / node after performing CHO / CPAC from the source PCell / PSCell / node to the target PCell / PSCell / node.

[0076] In a second embodiment, the network indication process may include the network sending an indication to the UE indicating that the UE will maintain the CHO and / or CPAC candidate cell configuration after completing / performing the handover procedure and / or the PSCell addition / modification procedure (e.g., a “maintain CHO / CPAC” or “maintain conditional reconfiguration” indicator).

[0077] In a third embodiment, the network indication process may include the network sending an indication to the UE indicating whether CHO and / or CPAC return to the source is allowed (e.g., a "return CHO / CPAC" or "return conditional reconfiguration" indicator). In other words, an indication indicating whether CHO / CPAC from the target PCell / PSCell / node back to the source PCell / PSCell / node is allowed after performing CHO / CPAC from the source PCell / PSCell / node to the target PCell / PSCell / node. The indication in these embodiments may be sent via broadcast signaling (e.g., system information) or dedicated RRC signaling (e.g., an RRCReconfiguration message).

[0078] In a fourth embodiment, the network indication process may include the network informing the UE which candidate cell configuration is maintained after completion / execution of the handover procedure and / or PSCell addition / modification procedure. For example, an indication may be added to the RRCReconfigration message in the CHO / CPAC (e.g., a "maintainCondReconfig" indicator under the IE CondReconfigToAddMod) to indicate whether the indicated candidate cell configuration is maintained after completion / execution of the handover procedure and / or PSCell addition / modification procedure.

[0079] In a fifth embodiment, the network indication process may include the network informing the UE whether the execution conditions set by the initiating node (e.g., source node for CHO, MN for MN initiated CPAC, S-SN for SN initiated CPAC) for all candidate cells or indicated candidate cells are maintained after completion / execution of the handover procedure and / or PSCell addition / modification procedure. For example, an indication is added to the RRC Reconfigration message of the CHO / CPAC to indicate whether the execution conditions are maintained after completion / execution of the handover procedure and / or PSCell addition / modification procedure. In some embodiments, an indication is added to the RRC Reconfigration message of each candidate cell (e.g., "maintainCondReconfigExecCond" indicator under IE CondReconfigToAddMod) to indicate whether the execution conditions of the indicated candidate cells are maintained after completion / execution of the handover procedure and / or PSCell addition / modification procedure.

[0080] In case of consecutive CHO / CPAC, the execution conditions of the subsequent CHO / CPAC may be configured. Since the execution conditions are provided by the source node for CHO or the initiating node for CPAC, when a successful completion of CHO / CPAC to the target cell occurs, the pre-configured execution conditions for the previous CHO / CPAC evaluation may become invalid. The network may need to provide the UE with updated / new execution conditions for the subsequent CHO / CPAC evaluation. Providing the execution conditions of the subsequent CHO / CPAC may be performed according to the following embodiments.

[0081] In the first embodiment, the source node informs the target node about other prepared candidate cell information when requesting a CHO / CPAC procedure. The target node generates execution conditions corresponding to the other candidate cells and forwards the execution conditions to the source node. The execution conditions can be included in the candidate cell configuration (e.g., an RRCReconfiguration message).

[0082] In the second embodiment, when the UE successfully completes the CHO / CPAC procedure to the target cell, or the UE triggers the execution of the CHO / CPAC procedure but has the configuration of another candidate cell, the UE notifies these candidate cell information (e.g., candidate cell ID, CGI, or / and PCI+frequency of the cell whose configuration of the candidate cell is maintained at the UE side) to the target cell or the cell indicated by the NW whose configuration of the candidate cell is to be maintained after the completion / execution of CHO / CPAC. The target cell can configure or update the execution conditions of these candidate cells via the RRCReconfigration message.

[0083] In a third embodiment, upon successful completion / execution of the handover procedure or PSCell addition / modification procedure to the target cell, the source node informs the target cell of other candidate cell information (e.g., candidate cell ID, CGI, and / or PCI+frequency of the candidate cell). The target cell can configure or update the execution conditions of these candidate cells via an RRCReconfigration message.

[0084] In case of conditional handover ("CHO"), there may be two alternatives to inform the target cell about other candidate cell information. First, the UE informs the target cell of the candidate cell information (e.g., candidate cell ID; frequency + PCI; CGI) stored in the target cell via an RRCReconfigurationComplete message upon execution / completion of CHO to the target cell. Second, upon receiving an HO success message from the target node (i.e., the first CHO execution to the target is successful), the source node informs the target node of all other configured candidate cell information (e.g., candidate cell ID; frequency + PCI; CGI) via an Xn / X2 message.

[0085] In the case of CPAC, the UE informs the target PSCell of the stored candidate cell information (e.g., candidate cell ID; frequency + PCI; CGI) via an RRCReconfigurationComplete message to the target SN upon execution / completion of CPAC to the target PSCell. The RRCReconfigurationComplete message to the target SN is included in an RRC Reconfiguration Complete message to the MN. The MN then forwards the RRCReconfigurationComplete message to the target SN.

[0086] Multiple CHO / CPAC configurations may require signaling optimization. A cell configuration template (e.g., source cell configuration or defined common part configuration for multiple cell configurations) can be defined. It can use the template to configure multiple cells based on similar configurations. When requesting CHO to a candidate node, the source node sends the configuration template to the candidate node via a HO Request message. The configuration template is included in an inter-node RRC message (e.g., Handover Preparation Information message) in the HO Request message. When requesting SN-initiated CPC to a candidate node, the source SN sends the configuration template to the MN via a SN Change Request message. The MN sends the received configuration template to the candidate SN via a SN Add Request message. The configuration template may be included in an inter-node RRC message (e.g., a CG-Config message in a SN Change Request message, or a CG-ConfigInfo message in a SN Add Request message). When requesting MN-initiated CPC / CPA to a candidate node, the MN sends the configuration template to the candidate SN via a SN Add Request message. The configuration template may be included in an inter-node RRC message (eg, a CG-ConfigInfo message) within an SN addition request message.

[0087] When multiple candidate cells are configured, each cell configuration can be a delta configuration based on a configuration template. After a handover or PSCell addition / modification execution is successfully completed, the UE should retain the source configuration or cell configuration template and other candidate cell configurations. When the next CHO or CPAC execution condition is met, the UE should apply the corresponding candidate cell configuration based on the original source configuration or cell configuration template.

[0088] 6A-6B illustrate continuous conditional handover (CHO). In FIG. 6A, a source node ("source") transmits handover ("HO") request messages 602, 604, 606 to a target node to request a CHO. A CHO request message is transmitted for each candidate cell. HO request 1 602 is for cell 1 and includes other candidate cell information (e.g., cell 2 and cell 3), HO request 2 604 is for cell 2 and includes other candidate cell information (e.g., cell 1 and cell 3), and HO request 3 606 is for cell 3 and includes other candidate cell information (e.g., cell 1 and cell 2). The HO request messages may include an indication to request continuous CHO (e.g., a "continuous CHO request" indicator), other candidate target node information (e.g., candidate node ID), or / and other candidate PCell information (e.g., candidate cell ID, PCI+frequency, CGI).

[0089] The target node sends a CHO response 608, 610, 612 (i.e., HO request acknowledgement message) to the source node, including the configuration of the CHO candidate cells. A CHO response message is sent for each candidate cell. The execution conditions for subsequent CHO based on other candidate cells may be pre-configured. When an indication to request successive CHO is received, the target cell generates a set of execution conditions, which are linked for each other candidate cell. The set of execution conditions is included in the generated candidate cell configuration (e.g., RRC Reconfiguration message). For example, for candidate cell 1, the target 1 node provides the candidate cell configuration for cell 1 to the source node as part of the HO request 1 acknowledgement message 608, and provides the source node with an execution condition set including the execution conditions for cell 2 and cell 3. The execution condition set is also included in the RRC Reconfiguration message for the candidate cell configuration. The remaining communications of the successive CHO procedure are shown in FIG. 6B.

[0090] Figure 6B illustrates additional features of the continuous conditional handover (CHO) illustrated in Figure 6A. The source node sends a reconfiguration message 614 (e.g., an RRCReconfiguration message) to the UE, including the configuration of CHO candidate cells and the corresponding CHO execution condition for each CHO candidate cell. The message 614 may include an indication associated with each candidate cell to indicate whether the indicated candidate cell configuration can be maintained after completion / execution of the handover procedure. The UE responds with a reconfiguration complete message 616 (e.g., an RRCReconfigurationComplete message) to the source node.

[0091] The UE maintains a connection with the source node after receiving the CHO configuration and starts evaluating the CHO execution conditions of the candidate cells 618. In one embodiment, the UE evaluates whether the execution conditions of candidate cell 1 are met, and then the UE triggers a CHO for candidate cell 1. The UE applies the corresponding configuration stored in its selected candidate cell (e.g., cell 1), synchronizes to the candidate cell, and completes the CHO procedure by sending a reconfiguration complete message 620 (e.g., an RRCReconfigurationComplete message) to the target node (e.g., target 1). The target node sends a HO success message 622 to the source node to inform that the UE has successfully accessed the target cell.

[0092] The UE keeps all other candidate cell configurations (e.g., cell 2, cell 3 configurations) or keeps the candidate cell configurations indicated as "keep" in the reconfiguration message for CHO 614 and starts evaluating the CHO execution conditions preconfigured by the target cell (i.e., cell 1) 624. If the UE determines that the execution conditions for candidate cell 3 are met, the UE triggers CHO for candidate cell 3 626. The UE completes the CHO procedure by sending a reconfiguration complete message 628 (e.g., RRCReconfigurationComplete message) to the target node (e.g., target 2). The target node sends a HO success message 630 to the source node to inform that the UE has successfully accessed the target cell. The UE keeps other candidate cell configurations (e.g., cell 1, cell 2 configurations) and starts evaluating the CHO execution conditions preconfigured by cell 3 632.

[0093] In some embodiments, the source node may not inform the target node of other candidate cell information when requesting CHO 602, 604, 606. In some embodiments, the target node shall not generate execution conditions for other candidate cells 608, 610, 612. In some embodiments, the UE shall inform the target cell (e.g., target 1) of all other candidate cell information whose candidate cell configurations are maintained at the UE side via a reconfiguration complete message 622. In some embodiments, after receiving the HO success message 622 from the target node, the source node informs the target node of all other candidate cell information via Xn / X2 messages.

[0094] In some embodiments, there may be a return of CHO to the source. The difference is that the source node may include an indication of CHO return. If CHO return to the source is allowed, the source node includes an indication (e.g., "CHO_return" indicator) in the HO request message 602, 604, 606 indicating that CHO return to the source is allowed / requested. This indication can be forwarded as an IE in the Xn / X2 message (e.g., HO request message) or as an IE in the RRC message in the Xn / X2 message (e.g., Handover Preparation Information message). The target node generates an execution condition for the source cell and includes the execution condition in the reconfiguration message of the candidate cell. The target node transmits the message to the source cell. At 624, after completion / execution of CHO to the target cell (e.g., selected candidate cell 1), the UE maintains the source cell configuration. The UE starts CHO evaluation based on the execution condition preconfigured by the target cell. At 626, if the UE evaluates that the execution conditions of the source cell are met, the UE triggers the CHO back to the source cell.

[0095] 7A-7B illustrate continuous conditional PSCell addition / modification ("CPAC"). In FIG. 7A, the MN initiates a conditional SN addition / modification procedure (CPAC) by sending a SN addition request message to a target SN. An SN addition request 1 message 702 is sent from the MN to target 1, and an SN addition request 2 message 704 is sent from the MN to target 2. In each message, the MN may include an indication to request continuous CPAC (e.g., a "continuous CPAC request" indicator), other candidate SN node information (e.g., candidate node ID), or / and other candidate PSCell information (e.g., candidate cell ID, PCI+ frequency, CGI).

[0096] The target SN node sends an SN Addition Request Acknowledgement message to the MN, including the configuration of the candidate PSCell. An SN Addition Request 1 Acknowledgement message 706 is sent from Target 1 to the MN, and an SN Addition Request 2 Acknowledgement message 708 is sent from Target 2 to the MN. If an indication to request / allow successive CPAC is received, the target SN node shall generate a set of execution conditions, which are linked for each other candidate PSCell. The set of execution conditions is included in the generated candidate cell configuration (e.g., RRCReconfiguration message). For example, for candidate cell 1, the target 1 node provides the MN with an execution condition set including the candidate cell configuration of cell 1 and the execution conditions of cell 2. The execution condition set is also included in the RRCReconfiguration message of the candidate cell configuration. When the MN initiates CPAC, the MN determines the execution conditions of the candidate PSCell 710. The remaining communications of the successive CPAC procedure are shown in FIG. 7B.

[0097] Figure 7B illustrates additional features of the successive cell change / addition procedure illustrated in Figure 7A. The MN sends a reconfiguration message 714 (e.g., RRCReconfiguration message) to the UE including the CPAC candidate cell configuration and corresponding execution conditions for each candidate cell. In the reconfiguration message, the MN may indicate which candidate cells and / or execution conditions may be maintained after completion / execution of CPAC for the target cell. The UE responds with a reconfiguration complete message 716 (e.g., RRCReconfigurationComplete) to the MN. The UE starts evaluating the CPA / CPC execution conditions for the candidate cells. If the UE determines that the execution conditions for candidate cell 1 are met, the UE triggers CPAC for candidate cell 1 718.

[0098] The UE applies the corresponding configuration stored for its selected candidate PSCell (e.g., Cell 1), synchronizes to the candidate PSCell, and sends a reconfiguration complete message 720 to the MN, including the RRCReconfigurationComplete message embedded with the target SN. The MN forwards the SN reconfiguration complete message 722 to the target SN (e.g., Target 1). The UE maintains the other candidate PSCell configuration (e.g., Cell 2 configuration) or maintains the candidate cell configuration indicated as "maintained" in the RRCReconfigration message of the CPAC 724. The UE deletes the execution conditions set by the MN and starts evaluating the CPAC execution conditions preconfigured by Cell 1. If the UE determines that the execution conditions of candidate cell 2 are met, the UE triggers CPAC for candidate cell 2 726. The UE sends a reconfiguration complete message 728 to the MN. The MN forwards the SN reconfiguration complete message 730 to the target SN (e.g., Target 2). The UE maintains 732 other candidate PSCell configurations (eg, cell 1 configuration) and begins evaluating the CPAC execution conditions preconfigured by cell 2.

[0099] In some embodiments, for SN-initiated CPAC, the source SN sends an SN Change Request message to the MN to request an SN-initiated SN change procedure, and the execution conditions for the first CPAC execution are generated by the source SN. In some embodiments, the MN shall not inform the target SN of other candidate cell information when requesting CPA / CPC 702, 704. In some embodiments, the target SN shall not generate execution conditions for other candidate cells 706, 708. In some embodiments, after triggering the first CPA for the target cell, the UE shall keep the execution conditions provided by the MN or keep the execution conditions indicated as "maintained" in the RRCReconfigration message of CPAC, and continue to evaluate other candidate cells for CPC execution based on the configured execution conditions. In some embodiments, the UE shall inform the target SN node (e.g., target SN_1) of all other candidate cell information via the SN RRCReconfigurationComplete message embedded in the RRC reconfiguration complete to the MN 720, 728.

[0100] CPAC may be returned to the source. If CPAC return to the source is allowed, the MN may include an indication (e.g., "CPAC_return" indicator) in the SN Addition Request message 702, 704 indicating that CPAC return to the source is allowed / requested. This indication can be forwarded as an IE in the Xn / X2 message (e.g., SN Addition Request message) or as an IE in the RRC message in the Xn / X2 message (e.g., CG-ConfigInfo message). At 706, 708, the target node generates execution conditions for the source cell and includes the execution conditions in the RRCReconfigration message of the candidate cell. At 724, after completion / execution of CPAC to the target cell (e.g., selected candidate cell 1), the UE maintains the source cell configuration. The UE starts CPAC evaluation based on the execution conditions preconfigured by the target cell. At 726, when the execution conditions of the source cell are met, the UE triggers CPAC back to the source cell.

[0101] The above-described systems and processes may be encoded in a computer-readable medium, such as a signal-carrying medium, a memory, or may be programmed into a device, such as one or more integrated circuits, one or more processors, or may be processed by a controller or computer. The data may be analyzed in a computer system and used to generate a spectrum. If the method is performed by software, the software may reside in a non-volatile or volatile memory that communicates with or is interfaced to a storage device, a synchronization device, a communication interface, or a transmitter. The circuit or electronic device is designed to transmit the data to another location. The memory may include an ordered list of executable instructions to perform the logic functions. The described logic functions or any system elements may be implemented via optical circuits, digital circuits, source code, analog circuits, analog sources such as analog electrical signals, audio signals, video signals, or combinations thereof. The software may be embodied in any computer-readable medium or signal-carrying medium for use by or in association 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 that may selectively fetch instructions from an instruction-executable system, apparatus, or device that may also execute instructions.

[0102] A "computer-readable medium", "machine-readable medium", "propagating signal" medium, and / or "signal-bearing medium" may include any device that stores, communicates, propagates, or transports software for use by or in connection with an instruction-executable system, apparatus, or device. A machine-readable medium may 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 examples of machine-readable media includes an electrical connection "electronic" having one or more wires, a portable magnetic or optical disk, a random access memory "RAM", a read-only memory "ROM", a volatile memory such as an erasable programmable read-only memory (EPROM or flash memory), or an optical fiber. A machine-readable medium may also include a tangible medium on which the software is printed, so that the software may be stored electronically as an image or in another format (e.g., via optical scanning) and then compiled and / or interpreted, or otherwise processed. The processed medium may then be stored in a computer and / or machine memory.

[0103] The illustrations of the embodiments described herein are intended to provide a general understanding of the structures of the various embodiments. The illustrations are not intended to serve as a complete description of all of the elements and features of the apparatus and systems that utilize the structures or methods described herein. Many other embodiments will be apparent to those skilled in the art upon review of the present disclosure. Other embodiments may be utilized and derived from the present disclosure, such that structural and logical substitutions and modifications may be made without departing from the scope of the present disclosure. Furthermore, the figures are merely representative and may not be drawn to scale. Certain proportions within the illustrations may be exaggerated, while other proportions may be minimized. Thus, the present disclosure and the drawings should be considered illustrative rather than limiting.

[0104] 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 spontaneously limit the scope of the present application to any particular invention or inventive concept. Furthermore, although specific embodiments have been illustrated and described herein, it should be understood that any subsequent configurations 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 subsequent adaptations or modifications of the various embodiments. Combinations of the above embodiments, as well as other embodiments not specifically described herein, will be apparent to those of skill in the art upon review of the description.

[0105] 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. Changes in the arrangement and type of components may be made without departing from the spirit or scope of the claims as set forth herein. Additional, different, or fewer components may be provided.

[0106] The subject matter disclosed above should be considered as 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 present invention. Thus, to the maximum extent permitted by law, the scope of the present invention should be determined by the broadest permissible interpretation of the following claims and their equivalents, and should not be limited or restricted by the foregoing detailed description. Although various embodiments of the present 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 present invention. Thus, the present invention should not be limited in light of the appended claims and their equivalents.

Claims

1. 1. A method for wireless communication, comprising: Sending a secondary node (SN) addition request by a master node (MN) to a first target secondary node (SN) for SN change from a source SN or SN addition of the first target SN, the request including candidate cell information of the first target SN; receiving, by the MN, a response from the first target SN, the response including at least one candidate cell configuration; transmitting, by the MN, to a user equipment (UE), a radio resource control (RRC) message having the at least one candidate cell configuration and the one or more execution conditions for each of a plurality of candidate cells, to cause the UE to: trigger a change from the source SN to the first target SN or an SN addition of the first target SN based on a candidate cell configuration of the at least one candidate cell configuration when one or more execution conditions for one of the candidate cells from the first target SN are satisfied; and then trigger a change from the source SN to the second target SN or an SN addition of the second target SN based on another candidate cell configuration of the at least one candidate cell configuration when an execution condition for a second target SN provided by the first target SN is satisfied; and wherein the at least one candidate cell configuration is maintained after completion of the change from the source SN to the first target SN or after completion of the SN addition of the first target SN in order to perform the change from the source SN to the second target SN or the SN addition of the second target SN.

2. The method of claim 1 , wherein the candidate cell information includes one or more candidate primary secondary cell (PSCell) identities.

3. A method for wireless communication, comprising: Sending a secondary node (SN) addition request by a master node (MN) to a target secondary node (SN) for SN change from a source SN or SN addition of the target SN, the request including candidate cell information of the target SN; receiving, by the MN, a response from the target SN, the response including at least one candidate cell configuration; sending, by the MN to a user equipment (UE), a radio resource control (RRC) message having at least one candidate cell configuration and the one or more execution conditions for each candidate cell, to cause a change from the source SN to the target SN or an SN addition of the target SN based on a candidate cell configuration of the at least one candidate cell configuration when one or more execution conditions for one of the candidate cells from the target SN are satisfied; wherein the MN provides measurement results for one or more cells in the target SN, the measurement results for each cell including an indicator of whether the cell is a candidate PSCell.

4. A method for wireless communication, comprising: Sending a secondary node (SN) addition request by a master node (MN) to a target secondary node (SN) for SN change from a source SN or SN addition of the target SN, the request including candidate cell information of the target SN; receiving, by the MN, a response from the target SN, the response including at least one candidate cell configuration; sending, by the MN to a user equipment (UE), a radio resource control (RRC) message having at least one candidate cell configuration and the one or more execution conditions for each candidate cell, to cause a change from the source SN to the target SN or an SN addition of the target SN based on a candidate cell configuration of the at least one candidate cell configuration when one or more execution conditions for one of the candidate cells from the target SN are satisfied; wherein the SN addition request for a target SN includes at least one of an indication indicating an SN change from the target SN back to the source SN after the SN change is allowed to be performed on the target SN, or an indication indicating an SN change from the target SN to another target SN after the SN change is allowed to be performed on the target SN or after the SN addition of the target SN is allowed to be performed.

5. A method for wireless communication, comprising: Sending a secondary node (SN) addition request by a master node (MN) to a target secondary node (SN) for SN change from a source SN or SN addition of the target SN, the request including candidate cell information of the target SN; receiving, by the MN, a response from the target SN, the response including at least one candidate cell configuration; sending, by the MN to a user equipment (UE), a radio resource control (RRC) message having at least one candidate cell configuration and the one or more execution conditions for each candidate cell, to cause a change from the source SN to the target SN or an SN addition of the target SN based on a candidate cell configuration of the at least one candidate cell configuration when one or more execution conditions for one of the candidate cells from the target SN are satisfied; and the RRC message includes: For the candidate cell configuration of the at least one candidate cell configuration, an indication indicating whether the candidate cell configuration of the at least one candidate cell configuration is maintained after completion of the change from the source SN to the target SN or is maintained after completion of the SN addition of the target SN; and an indication of whether the one or more performance conditions for each candidate cell or the one or more performance conditions for an indicated candidate cell are maintained after completion of the change from the source SN to the target SN or after completion of the SN addition of the target SN. The method includes at least one of the following:

6. 1. A method for wireless communication, comprising: receiving, from a master node (MN), by a first target secondary node (SN), a secondary node (SN) addition request for SN change from a source SN or SN addition of the first target SN, the request including candidate cell information of the first target SN; sending, by the first target SN, a response to the MN including at least one candidate cell configuration; Including, the MN transmits a Radio Resource Control (RRC) message to a User Equipment (UE) having the at least one candidate cell configuration and one or more execution conditions for each of a plurality of candidate cells, causing the UE to trigger a change from the source SN to the first target SN or an SN addition of the first target SN based on a candidate cell configuration of the at least one candidate cell configuration when the one or more execution conditions for one of the candidate cells from the first target SN are satisfied, and then trigger a change from the source SN to the second target SN or an SN addition of the second target SN based on another candidate cell configuration of the at least one candidate cell configuration when an execution condition for a second target SN provided by the first target SN is satisfied; A method in which the at least one candidate cell configuration is maintained after completion of the change from the source SN to the first target SN or after completion of the SN addition of the first target SN, in order to perform the change from the source SN to the second target SN or the SN addition of the second target SN.

7. The method of claim 6 , wherein the candidate cell information includes one or more candidate primary secondary cell (PSCell) identities.

8. A method for wireless communication comprising: receiving, from a master node (MN), by a target secondary node (SN), a secondary node (SN) addition request for SN change from a source SN or SN addition of the target SN, the request including candidate cell information of the target SN; sending, by the target SN, a response to the MN including at least one candidate cell configuration; Including, The MN sends a radio resource control (RRC) message to a user equipment (UE) having at least one candidate cell configuration and one or more execution conditions for each candidate cell, and if the one or more execution conditions for one of the candidate cells from the target SN are met, triggers a change from the source SN to the target SN or an SN addition of the target SN based on the candidate cell configuration, and the MN provides measurement results of one or more cells in the target SN, the measurement results for each cell including an indicator of whether the cell is a candidate PSCell.

9. The method of claim 6 , wherein the candidate cell information includes one or more candidate cell identities configured as candidate PSCells.

10. A method for wireless communication, comprising: receiving, from a master node (MN), by a target secondary node (SN), a secondary node (SN) addition request for SN change from a source SN or SN addition of the target SN, the request including candidate cell information of the target SN; sending, by the target SN, a response to the MN including at least one candidate cell configuration; Including, The MN sends a Radio Resource Control (RRC) message to a user equipment (UE) having at least one candidate cell configuration and one or more execution conditions for each candidate cell, and if the one or more execution conditions for one of the candidate cells from the target SN are met, triggers a change from the source SN to the target SN or an SN addition of the target SN based on the candidate cell configuration, wherein the SN addition request for a target SN includes at least one of an indication indicating an SN change from the target SN back to the source SN after SN change execution for one target SN is allowed, or an indication indicating an SN change from the target SN to another target SN after SN change execution for one target SN or SN addition for the target SN is allowed.

11. A method for wireless communication, comprising: receiving, from a master node (MN), by a target secondary node (SN), a secondary node (SN) addition request for SN change from a source SN or SN addition of the target SN, the request including candidate cell information of the target SN; sending, by the target SN, a response to the MN including at least one candidate cell configuration; Including, The MN transmits a Radio Resource Control (RRC) message to a user equipment (UE) having at least one candidate cell configuration and one or more execution conditions for each candidate cell, and triggers a change from the source SN to the target SN or an SN addition of the target SN based on the candidate cell configuration if the one or more execution conditions for one of the candidate cells from the target SN are satisfied, the RRC message comprising: For each candidate cell configuration, an indication of whether the candidate cell configuration is to be maintained after completion of the change from the source SN to the target SN or after completion of the SN addition of the target SN; or an indication of whether the one or more performance conditions for each candidate cell or the one or more performance conditions for an indicated candidate cell are maintained after completion of the change from the source SN to the target SN or after completion of the SN addition of the target SN. The method includes at least one of the following:

12. 1. A method for wireless communication, comprising: receiving, by a user equipment (UE), a radio resource control (RRC) message from a master node (MN) having at least one candidate cell configuration and one or more execution conditions for each of the at least one candidate cell; When the one or more execution conditions for one of the candidate cells from a first target secondary node (SN) are satisfied, performing, by the UE, a change from a source secondary node (SN) to the first target SN or a secondary node (SN) addition of the first target SN based on a candidate cell configuration of the at least one candidate cell configuration; When an execution condition for a second target SN provided by the first target SN is satisfied, performing a change from the source SN to the second target SN or an SN addition of the second target SN based on another candidate cell configuration of the at least one candidate cell configuration by the UE; and wherein the at least one candidate cell configuration is maintained after completion of the change from the source SN to the first target SN or after completion of the SN addition of the first target SN in order to perform the change from the source SN to the second target SN or the SN addition of the second target SN.

13. A method for wireless communication comprising: receiving, by a user equipment (UE), a radio resource control (RRC) message from a master node (MN) having at least one candidate cell configuration and one or more execution conditions for each of the at least one candidate cell; When the one or more execution conditions for one of the candidate cells from a target secondary node (SN) are satisfied, a change from a source secondary node (SN) to a target SN or a secondary node (SN) addition of the target secondary node is performed by the UE based on the candidate cell configuration. and the RRC message includes: for each candidate cell configuration, an indication of whether the candidate cell configuration will be maintained after completion of the change from the source secondary node to the target secondary node or whether the candidate cell configuration will be maintained after completion of the secondary node addition of the target secondary node; or an indication of whether the one or more performance conditions for each candidate cell or the one or more performance conditions for an indicated candidate cell are maintained after completion of the change from the source SN to the target SN or after completion of the SN addition of the target SN. The method includes at least one of the following:

14. sending an RRC completion message by the UE to the MN to notify the MN of the change from the source secondary node to the target secondary node or the addition of the secondary node of the first target SN, the RRC completion message including a second RRC completion message sent to the first target SN; The method of claim 12 further comprising:

15. A wireless communication device comprising a processor and a memory, the processor configured to read a code from the memory and to perform a method according to any one of claims 1 to 5.

16. A wireless communication device comprising a processor and a memory, the processor configured to read a code from the memory and to perform a method according to any one of claims 6 to 11.

17. A wireless communication device comprising a processor and a memory, the processor configured to read a code from the memory and to perform a method according to any one of claims 12 to 14.

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