Method for adding and changing a primary cell in a conditional secondary cell group

Abstract

A master node (MN) may send an SN add request message to a target secondary node (SN), the SN add request message having an indication of the maximum number of candidate PSCells that the target SN may configure. In response to the SN add request message, the MN may receive an SN add request confirmation message from the target SN having at least one candidate PSCell configuration. If data forwarding is required, the MN may send a data forwarding message to the source SN, the data forwarding message having an indication that the data forwarding is for a CPAC-based procedure. The MN may send an RRC message to the wireless communication device, the RRC message including at least one candidate PSCell configuration and one or more associated CPAC execution conditions.

Description

Technical Field

[0001] The present disclosure relates generally to wireless communications, including but not limited to systems and methods for conditional primary cell (PSCell) addition and change in a secondary cell group. Background Art

[0002] The 3rd Generation Partnership Project (3GPP), a standards organization, is currently specifying a new radio interface called 5G New Radio (5GNR) and the Next Generation Packet Core (NG-CN or NGC). 5G NR will have three main components: the 5G Access Network (5G-AN), the 5G Core (5GC), and the User Equipment (UE). To facilitate the implementation of different data services and requirements, the elements of the 5GC (also known as network functions) have been simplified, with some of them being software-based, allowing them to be adjusted as needed. Summary of the Invention

[0003] The example embodiments disclosed herein are intended to address issues related to one or more of the problems existing in the prior art, as well as to provide additional features that will become apparent with reference to the following detailed description when taken in conjunction with the accompanying drawings. According to various embodiments, example systems, methods, devices, and computer program products are disclosed herein. However, it should be understood that these embodiments are presented as examples and not as limitations, and it will be clear to those of ordinary skill in the art reading this disclosure that various modifications may be made to the disclosed embodiments while remaining within the scope of this disclosure.

[0004] At least one aspect relates to a system, method, apparatus, or computer-readable medium. A master node (MN) may send an SN add request message to a target secondary node (SN), the SN add request message having an indication of the maximum number of primary cells (PSCells) in a candidate secondary cell group that can be configured by the target SN. The MN may receive an SN add request confirmation message having at least one candidate PSCell configuration from the target SN in response to the SN add request message. If data forwarding is required, the MN may send a data forwarding message to the source SN, the data forwarding message having an indication that the data forwarding is for a process based on conditional PSCell addition or change (CPAC). The MN may send a radio resource control (RRC) message including at least one candidate PSCell configuration and one or more associated CPAC execution conditions to a wireless communication device to cause the wireless communication device to perform a CPAC process on the target SN when the candidate PSCell satisfies at least one of the one or more CPAC execution conditions.

[0005] In some embodiments, an indication of the maximum number of candidate PSCells may be included in an information element of the SN add request message. In some embodiments, an indication that the data forwarding is for a CPAC procedure may be included in an information element of the data forwarding message. In some embodiments, the wireless communication device may select a candidate PSCell residing in a candidate SN other than the source SN, or a candidate PSCell residing in the source SN when a single radio bearer three (SRB3) is not configured, to perform a CPAC procedure on the selected candidate PSCell.

[0006] In some embodiments, the MN may receive an RRC message from the wireless communication device indicating the execution of the CPAC process for the selected candidate PSCell. In some embodiments, the MN may send an Xn interface or X2 interface message to one or more candidate SNs other than the target SN in response to the RRC message to release the resources reserved for the CPAC process. In some embodiments, the MN may receive an Xn interface or X2 interface message from the target SN indicating the successful completion of the CPAC process, the Xn interface or X2 interface message including the identification information of the selected PSCell. In some embodiments, the MN may send another Xn interface or X2 interface message to one or more candidate SNs other than the target SN to release the resources reserved for the CPAC process.

[0007] In some embodiments, when the selected PSCell is not a candidate PSCell residing in the source SN, the MN may send an SN release message to the source SN to indicate the release of the source SN's resources and cause the source SN to stop providing user data to the wireless communication device. In some embodiments, the MN may determine whether to modify or cancel the CPAC configuration of one or more candidate PSCells based on measurement results related to the target SN. In some embodiments, the MN may send a message to the target SN indicating the modification or cancellation of the CPAC configuration of one or more candidate PSCells, the message including identification information about the one or more candidate PSCells to be modified or canceled.

[0008] In some embodiments, the MN may send measurement results related to the target SN to the target SN, wherein the target SN determines whether to modify or cancel the CPAC configuration of one or more candidate PSCells based on the measurement results related to the target SN. In some embodiments, the target SN may send a message to the MN indicating the modification or cancellation of the CPAC configuration of one or more candidate PSCells, the message including identification information about the one or more candidate PSCells to be modified or canceled. In some embodiments, the MN may send an Xn interface or X2 interface message to the target SN to request the release of the CPAC configuration of the configured candidate PSCell. In some embodiments, the Xn interface or X2 interface message may include at least one of the following: identification information about the configured candidate PSCell, or an indication about releasing the CPAC configuration related to replacing the CPAC configuration with a new CPAC configuration.

[0009] In some embodiments, the MN may receive an Xn interface or X2 interface message from the target SN to request the release of the CPAC configuration of the configured candidate PSCell. In some embodiments, the Xn interface or X2 interface message may include at least one of the following: identification information about the configured candidate PSCell, or an indication about releasing the CPAC configuration related to replacing the CPAC configuration with a new CPAC configuration. In some embodiments, the MN may send an Xn interface or X2 interface message to the target SN to request the addition of a new CPAC configuration. In some embodiments, the Xn interface or X2 interface message may include at least one of the following: identification information of the PSCell to be modified, an updated source secondary cell group (SCG) configuration, a measurement result related to the target SN, or an indication about adding the CPAC configuration related to replacing the CPAC configuration with a new CPAC configuration.

[0010] In some embodiments, an indication of releasing the CPAC configuration associated with replacing the CPAC configuration with a new CPAC configuration may be included in an information element or cause value of an Xn interface or X2 interface request. In some embodiments, an indication of adding the CPAC configuration associated with replacing the CPAC configuration with a new CPAC configuration may be included in an information element or cause value of an Xn interface or X2 interface message. In some embodiments, the MN may send an indication of the maximum number of cells allowed to be configured as candidate cells for the CPAC process to the source SN via an Xn interface or X2 interface message. In some embodiments, the indication of the maximum number of cells may be included in an RRC message, which is included in an Xn interface or X2 interface message.

[0011] In some embodiments, the MN may receive a request from the source SN via an Xn or X2 interface message for a reference number of cells that are allowed to be configured as candidate cells for the CPAC process. In some embodiments, the reference number of cells may be included in an RRC message included in the Xn or X2 interface message. In some embodiments, the MN may determine whether to accept or reject the reference number of cells in the request.

[0012] At least one aspect relates to a system, method, apparatus, or computer-readable medium. A target secondary node (SN) may receive an SN add request message from a primary node, the SN add request message having an indication of the maximum number of primary cells (PSCells) in a candidate secondary cell group that can be configured by the target SN. The target SN may send an SN add request confirmation message with at least one candidate PSCell configuration to the MN in response to the SN add request message. If data forwarding is required, the MN may send a data forwarding message to the source SN, the data forwarding message having an indication that the data forwarding is for a process based on conditional PSCell addition or change (CPAC). The MN may send a radio resource control (RRC) message including at least one candidate PSCell configuration and one or more associated CPAC execution conditions to a wireless communication device to cause the wireless communication device to perform a CPAC process on the target SN when the candidate PSCell satisfies at least one of the one or more CPAC execution conditions.

[0013] In some embodiments, an indication of the maximum number of candidate PSCells may be included in an information element of the SN add request message. In some embodiments, an indication that the data forwarding is for a CPAC procedure may be included in an information element of the data forwarding message. In some embodiments, the wireless communication device may select a candidate PSCell residing in a candidate SN other than the source SN, or a candidate PSCell residing in the source SN when a single radio bearer three (SRB3) is not configured, to perform a CPAC procedure on the selected candidate PSCell.

[0014] In some embodiments, the MN may receive an RRC message from the wireless communication device indicating the execution of the CPAC process for the selected candidate PSCell. In some embodiments, the MN may send an Xn interface or X2 interface message to one or more candidate SNs other than the target SN in response to the RRC message to release the resources reserved for the CPAC process. In some embodiments, the target SN may send an Xn interface or X2 interface message to the MN indicating the successful completion of the CPAC process, the Xn interface or X2 interface message including the identification information of the selected PSCell. In some embodiments, the MN may send another Xn interface or X2 interface message to one or more candidate SNs other than the target SN to release the resources reserved for the CPAC process.

[0015] In some embodiments, when the selected PSCell is not a candidate PSCell residing in the source SN, the MN may send an SN release message to the source SN to indicate the release of the source SN's resources and cause the source SN to stop providing user data to the wireless communication device. In some embodiments, the MN may determine whether to modify or cancel the CPAC configuration of one or more candidate PSCells based on measurement results related to the target SN. In some embodiments, the target SN may receive a message from the MN indicating the modification or cancellation of the CPAC configuration of one or more candidate PSCells, the message including identification information about the one or more candidate PSCells to be modified or canceled.

[0016] In some embodiments, the target SN may receive measurement results related to the target SN from the MN, wherein the target SN determines whether to modify or cancel the CPAC configuration of one or more candidate PSCells based on the measurement results related to the target SN. In some embodiments, the target SN may send a message to the MN indicating modification or cancellation of the CPAC configuration of one or more candidate PSCells, the message including identification information about the one or more candidate PSCells to be modified or canceled. In some embodiments, the target SN may receive an Xn interface or X2 interface message from the MN to request the release of the CPAC configuration of the configured candidate PSCell. In some embodiments, the Xn interface or X2 interface message may include at least one of the following: identification information about the configured candidate PSCell, or an indication of releasing the CPAC configuration related to replacing the CPAC configuration with a new CPAC configuration.

[0017] In some embodiments, the target SN may send an Xn interface or X2 interface message to the MN to request the release of the CPAC configuration of the configured candidate PSCell. In some embodiments, the Xn interface or X2 interface message may include at least one of the following: identification information about the configured candidate PSCell, or an indication about releasing the CPAC configuration related to replacing the CPAC configuration with a new CPAC configuration. In some embodiments, the target SN may receive an Xn interface or X2 interface message from the MN to request the addition of a new CPAC configuration. In some embodiments, the Xn interface or X2 interface message may include at least one of the following: identification information of the PSCell to be modified, an updated source secondary cell group (SCG) configuration, a measurement result related to the target SN, or an indication about adding the CPAC configuration related to replacing the CPAC configuration with a new CPAC configuration.

[0018] In some embodiments, an indication of releasing the CPAC configuration associated with replacing the CPAC configuration with a new CPAC configuration may be included in an information element or cause value of an Xn interface or X2 interface request. In some embodiments, an indication of adding the CPAC configuration associated with replacing the CPAC configuration with a new CPAC configuration may be included in an information element or cause value of an Xn interface or X2 interface message. In some embodiments, the MN may send an indication of the maximum number of cells allowed to be configured as candidate cells for the CPAC process to the source SN via an Xn interface or X2 interface message. In some embodiments, the indication of the maximum number of cells may be included in an RRC message, which is included in an Xn interface or X2 interface message.

[0019] In some embodiments, the MN may receive a request from the source SN via an Xn or X2 interface message for a reference number of cells that are allowed to be configured as candidate cells for the CPAC process. In some embodiments, the reference number of cells may be included in an RRC message included in the Xn or X2 interface message. In some embodiments, the MN may determine whether to accept or reject the reference number of cells in the request.

[0020] At least one aspect relates to a system, method, apparatus, or computer-readable medium. A master node (MN) may receive an SN change required message from a source secondary node (SN). The MN may send an indication of the maximum number of primary cells (PSCells) in a candidate secondary cell group that can be configured by the target SN to a target SN in an SN add request message. In response to the SN add request message, the MN may receive at least one candidate PSCell configuration from the target SN in an SN add request confirm message. The MN may send an indication to the source SN in an Xn interface or X2 interface message that a change from the source SN to the target SN is associated with a process based on conditional PSCell addition or change (CPAC). The MN may send a radio resource control (RRC) message to a wireless communication device, the radio resource control (RRC) message including at least one candidate PSCell configuration and one or more associated CPAC execution conditions to cause the wireless communication device to perform a CPAC process on the target SN when the candidate PSCell satisfies at least one of the one or more CPAC execution conditions.

[0021] In some embodiments, the SN change request message may include an indication of the maximum number of candidate PSCells that can be configured by the target SN. In some embodiments, the indication of the maximum number of candidate PSCells may be included in an information element of the message. In some embodiments, the indication of the change associated with the CPAC-based procedure may be included in an information element of an Xn interface or X2 interface message. In some embodiments, the Xn interface or X2 interface message may include identification information of one or more PSCells that have been configured by the target SN.

[0022] In some embodiments, the Xn interface or X2 interface message may be an address indication message to provide data forwarding information to the source SN. In some embodiments, the Xn interface or X2 interface message may be an SN change confirmation message to confirm the release of resources of the source SN. In some embodiments, the SN change confirmation message may instruct the source SN to continue providing user data to the associated wireless communication device. In some embodiments, the wireless communication device may select a candidate PSCell residing in a candidate SN other than the source SN, or select a candidate PSCell residing in the source SN when a single radio bearer three (SRB3) is not configured, and perform a CPAC process on the selected candidate PSCell.

[0023] In some embodiments, the MN may receive an RRC message from the wireless communication device indicating the execution of the CPAC process for the selected candidate PSCell. In some embodiments, in response to the RRC message, the MN may send an Xn interface or X2 interface message to one or more candidate SNs other than the target SN to release the resources reserved for the CPAC process. In some embodiments, the MN may receive an Xn interface or X2 interface message from the target SN indicating the successful completion of the CPAC process, the Xn interface or X2 interface message including the identification information of the selected candidate PSCell. In some embodiments, the MN may send another Xn interface or X2 interface message to one or more candidate SNs other than the target SN to release the resources reserved for the CPAC process.

[0024] In some embodiments, when the selected candidate PSCell is not a candidate PSCell residing in the source SN, the MN may send another Xn interface or X2 interface message to the source SN to instruct the release of the source SN's resources. In some embodiments, the MN may cause the source SN to stop providing user data to the wireless communication device. In some embodiments, the another Xn interface or X2 interface message may be an SN release message or an SN change confirmation message. In some embodiments, the source SN may determine whether to modify or cancel the CPAC configuration of one or more candidate PSCells based on measurement results related to the target SN. In some embodiments, the source SN may inform the target SN of the identification information of the one or more candidate PSCells to be modified or canceled.

[0025] In some embodiments, the source SN may send measurement results related to the target SN to the target SN. In some embodiments, the target SN may determine whether to modify or cancel the CPAC configuration of one or more candidate PSCells based on the measurement results. In some embodiments, the MN may receive an Xn interface or X2 interface message from the source SN to request the release of the CPAC configuration of the configured candidate PSCell, and the Xn interface or X2 interface message includes at least one of the following: identification information of one or more candidate PSCells to be released or modified, or an indication of the release related to replacing the CPAC configuration with a new CPAC configuration. In some embodiments, the MN may send another Xn interface or X2 interface message to the target SN to request the release of the CPAC configuration of the configured candidate PSCell, and the other Xn interface or X2 interface message includes at least one of the following: identification information of one or more candidate PSCells to be released or modified, or an indication of the release related to replacing the CPAC configuration with a new CPAC configuration.

[0026] In some embodiments, the MN may receive an Xn interface or X2 interface message from the target SN to request the release of the CPAC configuration of the configured candidate PSCell, the Xn interface or X2 interface message including at least one of the following: identification information of one or more candidate PSCells to be released or modified, or an indication regarding the release of the CPAC configuration associated with replacing the CPAC configuration with a new CPAC configuration. In some embodiments, the MN may send an Xn interface or X2 interface message to the target SN to request the addition of a new CPAC configuration, the Xn interface or X2 interface message including at least one of the following: identification information of one or more candidate PSCells to be added or modified, an updated source secondary cell group (SCG) configuration, a measurement result associated with the target SN, or an indication regarding the addition of the CPAC configuration associated with replacing the CPAC configuration with a new CPAC configuration.

[0027] In some embodiments, an indication regarding the release of the CPAC configuration associated with replacing the CPAC configuration with a new CPAC configuration may be included in an information element or cause value of an Xn interface or X2 interface request. In some embodiments, an indication regarding the addition of the CPAC configuration associated with replacing the CPAC configuration with a new CPAC configuration may be included in an information element or cause value of an Xn interface or X2 interface message.

[0028] In some embodiments, the MN may send an indication of the maximum number of cells allowed to be configured as candidate cells for the CPAC process to the source SN via another Xn interface or X2 interface message. In some embodiments, the indication of the maximum number of cells may be included in an RRC message included in another Xn interface or X2 interface message. In some embodiments, the MN may receive a request from the source SN for a reference number of cells allowed to be configured as candidate cells for the CPAC process. In some embodiments, the reference number of cells may be included in an RRC message included in another Xn interface or X2 interface message. In some embodiments, the MN may determine whether to accept or reject the reference number of cells in the request.

[0029] At least one aspect relates to a system, method, apparatus, or computer-readable medium. A source secondary node (SN) may send an SN change request message to a master node (MN). The MN may send an indication of the maximum number of primary cells (PSCells) in a candidate secondary cell group that can be configured by the target SN to the target SN in an SN add request message. In response to the SN add request message, the MN may receive at least one candidate PSCell configuration from the target SN in an SN add request confirmation message. The SN may receive an indication from the MN in an Xn interface or X2 interface message that the change from the source SN to the target SN is associated with a process based on conditional PSCell addition or change (CPAC). The MN may send a radio resource control (RRC) message including at least one candidate PSCell configuration and one or more associated CPAC execution conditions to a wireless communication device to cause the wireless communication device to perform a CPAC process on the target SN when the candidate PSCell satisfies at least one of the one or more CPAC execution conditions.

[0030] In some embodiments, the SN change request message may include an indication of the maximum number of candidate PSCells that can be configured by the target SN. In some embodiments, the indication of the maximum number of candidate PSCells may be included in an information element of the message. In some embodiments, the indication of the change associated with the CPAC-based procedure may be included in an information element of an Xn interface or X2 interface message. In some embodiments, the Xn interface or X2 interface message may include identification information of one or more PSCells that have been configured by the target SN.

[0031] In some embodiments, the Xn interface or X2 interface message may be an address indication message to provide data forwarding information to the source SN. In some embodiments, the Xn interface or X2 interface message may be an SN change confirmation message to confirm the release of resources of the source SN. In some embodiments, the SN change confirmation message may instruct the source SN to continue providing user data to the associated wireless communication device. In some embodiments, the wireless communication device may select a candidate PSCell residing in a candidate SN other than the source SN, or select a candidate PSCell residing in the source SN when a single radio bearer three (SRB3) is not configured, and perform a CPAC process on the selected candidate PSCell.

[0032] In some embodiments, the MN may receive an RRC message from the wireless communication device indicating the execution of the CPAC process for the selected candidate PSCell. In some embodiments, the MN may send an Xn interface or X2 interface message to one or more candidate SNs other than the target SN in response to the RRC message to release the resources reserved for the CPAC process. In some embodiments, the MN may receive an Xn interface or X2 interface message from the target SN indicating the successful completion of the CPAC process, the Xn interface or X2 interface message including the identification information of the selected candidate PSCell. In some embodiments, the MN may send another Xn interface or X2 interface message to one or more candidate SNs other than the target SN to release the resources reserved for the CPAC process.

[0033] In some embodiments, when the selected candidate PSCell is not a candidate PSCell residing in the source SN, the source SN may receive another Xn interface or X2 interface message from the MN to indicate the release of the resources of the source SN. In some embodiments, the Xn interface or X2 interface message may cause the source SN to stop providing user data to the wireless communication device. In some embodiments, the another Xn interface or X2 interface message may be an SN release message or an SN change confirmation message. In some embodiments, the source SN may determine whether to modify or cancel the CPAC configuration of one or more candidate PSCells based on measurement results related to the target SN. In some embodiments, the source SN may inform the target SN of the identification information of the one or more candidate PSCells to be modified or canceled.

[0034] In some embodiments, the source SN may send measurement results related to the target SN to the target SN. In some embodiments, the target SN may determine whether to modify or cancel the CPAC configuration of one or more candidate PSCells based on the measurement results. In some embodiments, the source SN may send an Xn interface or X2 interface message to the MN to request the release of the CPAC configuration of the configured candidate PSCell, and the Xn interface or X2 interface message includes at least one of the following: identification information of one or more candidate PSCells to be released or modified, or an indication of releasing the CPAC configuration related to replacing the CPAC configuration with a new CPAC configuration. In some embodiments, the MN may send another Xn interface or X2 interface message to the target SN to request the release of the CPAC configuration of the configured candidate PSCell, and the other Xn interface or X2 interface message includes at least one of the following: identification information of one or more candidate PSCells to be released or modified, or an indication of releasing the CPAC configuration related to replacing the CPAC configuration with a new CPAC configuration.

[0035] In some embodiments, the MN may receive an Xn interface or X2 interface message from the target SN to request the release of the CPAC configuration of the configured candidate PSCell, the Xn interface or X2 interface message including at least one of the following: identification information of one or more candidate PSCells to be released or modified, or an indication regarding the release of the CPAC configuration associated with replacing the CPAC configuration with a new CPAC configuration. In some embodiments, the MN may send an Xn interface or X2 interface message to the target SN to request the addition of a new CPAC configuration, the Xn interface or X2 interface message including at least one of the following: identification information of one or more candidate PSCells to be added or modified, an updated source secondary cell group (SCG) configuration, a measurement result associated with the target SN, or an indication regarding the addition of the CPAC configuration associated with replacing the CPAC configuration with a new CPAC configuration.

[0036] In some embodiments, an indication regarding the release of the CPAC configuration associated with replacing the CPAC configuration with a new CPAC configuration may be included in an information element or cause value of an Xn interface or X2 interface request. In some embodiments, an indication regarding the addition of the CPAC configuration associated with replacing the CPAC configuration with a new CPAC configuration may be included in an information element or cause value of an Xn interface or X2 interface message.

[0037] In some embodiments, the source SN may receive an indication of the maximum number of cells allowed to be configured as candidate cells for the CPAC process from the MN via another Xn interface or X2 interface message. In some embodiments, the indication of the maximum number of cells may be included in an RRC message included in another Xn interface or X2 interface message. In some embodiments, the source SN may send a request to the MN for a reference number of cells allowed to be configured as candidate cells for the CPAC process. In some embodiments, the reference number of cells may be included in an RRC message included in another Xn interface or X2 interface message. In some embodiments, the MN may determine whether to accept or reject the reference number of cells in the request. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Various example embodiments of the present solution are described in detail below with reference to the accompanying drawings or figures. The drawings are provided for illustrative purposes only and depict only example embodiments of the present solution to facilitate the reader's understanding of the present solution. Therefore, the drawings should not be considered limiting of the breadth, scope, or applicability of the present solution. It should be noted that for clarity and ease of illustration, the drawings are not necessarily drawn to scale.

[0039] Figure 1 shows an example cellular communication network in which the techniques disclosed herein may be implemented according to embodiments of the present disclosure;

[0040] Figure 2 A block diagram illustrating an example base station and user equipment device according to some embodiments of the present disclosure is shown;

[0041] Figure 3 A block diagram illustrating an example wireless communication environment for secondary node change according to some embodiments of the present disclosure;

[0042] Figure 4-Figure 5 Various methods for a CPAC modification procedure initiated by a MN according to some embodiments of the present disclosure are shown;

[0043] Figure 6-Figure 7 Various methods for a CPAC modification procedure initiated by a source SN according to some embodiments of the present disclosure are shown;

[0044] Figure 8-Figure 9 Various methods for a CPAC modification procedure initiated by a target SN according to some embodiments of the present disclosure are shown;

[0045] Figure 10 An example method for a conditional SN change initiated by a MN according to some embodiments of the present disclosure is shown;

[0046] Figure 11 An example method for conditional SN addition according to some embodiments of the present disclosure is shown;

[0047] Figure 12-14 Various methods for SN-initiated conditional SN change according to some embodiments of the present disclosure are shown;

[0048] Figure 15 An example method of conditional SN modification initiated by an SN with MN participation according to some embodiments of the present disclosure is shown; and

[0049] Figure 16-17 Various flow charts are shown of example methods for adding and changing a conditional primary cell in a secondary cell group according to some embodiments of the present disclosure. DETAILED DESCRIPTION

[0050] Various example embodiments of the present solution are described below in conjunction with the accompanying drawings to enable a person of ordinary skill in the art to make and use the present solution. As will be clear to a person of ordinary skill in the art, after reading this disclosure, various changes or modifications may be made to the examples described herein without departing from the scope of the present solution. Therefore, the present solution is not limited to the example embodiments and applications described and illustrated herein. In addition, the specific order or hierarchy of steps in the methods disclosed herein are merely example methods. Based on design preferences, the specific order or hierarchy of steps of the disclosed methods or processes may be rearranged while remaining within the scope of the present solution. Therefore, unless expressly stated otherwise, a person of ordinary skill in the art will understand that the methods and techniques disclosed herein present various steps or actions in an example order, and that the present solution is not limited to the specific order or hierarchy presented.

[0051] The following acronyms are used throughout this disclosure:

[0052]

[0053]

[0054]

[0055] 1. Mobile communication technology and environment

[0056] Figure 1 An example wireless communication network and / or system 100 is shown in which the techniques disclosed herein may be implemented in accordance with embodiments of the present disclosure. In the following discussion, the wireless communication network 100 may be any wireless network, such as a cellular network or a narrowband Internet of Things (NB-IoT) network, and is referred to herein as "network 100." Such an example network 100 includes a base station 102 (hereinafter "BS 102"; also referred to as a wireless communication node) and a user equipment device 104 (hereinafter "UE 104"; also referred to as a wireless communication device) that may communicate with each other via a communication link 110 (e.g., a wireless communication channel), and a cluster of cells 126, 130, 132, 134, 136, 138, and 140 covering a geographic area 101. Figure 1 1 , BS 102 and UE 104 are contained within the respective geographic boundaries of cell 126. Each of the other cells 130, 132, 134, 136, 138, and 140 may include at least one base station operating within its allocated bandwidth to provide adequate radio coverage to its intended users.

[0057] For example, BS 102 may operate with the allocated channel transmission bandwidth to provide sufficient coverage to UE 104. BS 102 and UE 104 may communicate via downlink radio frames 118 and uplink radio frames 124, respectively. Each radio frame 118 / 124 may be further divided into subframes 120 / 127, which may include data symbols 122 / 128. In the present disclosure, BS 102 and UE 104 are described herein as non-limiting examples of "communication nodes," which may generally practice the methods disclosed herein. According to various embodiments of the present solution, such communication nodes may be capable of wireless and / or wired communication.

[0058] Figure 2 A block diagram of an example wireless communication system 200 for transmitting and receiving wireless communication signals (e.g., OFDM / OFDMA signals) according to some embodiments of the present solution is shown. The system 200 may include components and elements configured to support known or conventional operating features that need not be described in detail herein. In one illustrative embodiment, the system 200 may be used in applications such as Figure 1 Data symbols are communicated (eg, transmitted and received) in a wireless communication environment such as the wireless communication environment 100 of FIG. 1 , as described above.

[0059] System 200 generally includes a base station 202 (hereinafter referred to as "BS 202") and a user equipment device 204 (hereinafter referred to as "UE 204"). BS 202 includes a BS (base station) transceiver module 210, a BS antenna 212, a BS processor module 214, a BS memory module 216, and a network communication module 218, each of which is coupled to and interconnected with each other via a data communication bus 220 as needed. UE 204 includes a UE (user equipment) transceiver module 230, a UE antenna 232, a UE memory module 234, and a UE processor module 236, each of which is coupled to and interconnected with each other via a data communication bus 240 as needed. BS 202 communicates with UE 204 via a communication channel 250, which can be any wireless channel or other medium suitable for data transmission as described herein.

[0060] As will be understood by those skilled in the art, the system 200 may also include Figure 2Any number of other modules outside the modules shown. It will be understood by those skilled in the art that the various illustrative blocks, modules, circuits, and processing logic described in conjunction with the embodiments disclosed herein can be implemented in hardware, computer-readable software, firmware, or any actual combination thereof. In order to clearly illustrate this interchangeability and compatibility of hardware, firmware, and software, various illustrative components, blocks, modules, circuits, and steps are generally described in terms of their functions. Whether such functions are implemented as hardware, firmware, or software can depend on the specific application and the design constraints imposed on the entire system. People familiar with the concepts described herein can implement such functions in an appropriate manner for each specific application, but such implementation decisions should not be interpreted as limiting the scope of this disclosure.

[0061] According to some embodiments, the UE transceiver 230 may be referred to herein as an "uplink" transceiver 230, and includes a radio frequency (RF) transmitter and an RF receiver, each of which includes circuitry coupled to an antenna 232. A duplex switch (not shown) may alternatively couple the uplink transmitter or receiver to the uplink antenna in a time-duplexed manner. Similarly, according to some embodiments, the BS transceiver 210 may be referred to herein as a "downlink" transceiver 210, and includes an RF transmitter and an RF receiver, each of which includes circuitry coupled to an antenna 212. A downlink duplex switch may alternatively couple the downlink transmitter or receiver to the downlink antenna 212 in a time-duplexed manner. The operation of the two transceiver modules 210 and 230 may be coordinated in time such that the uplink receiver circuitry is coupled to the uplink antenna 232 for reception of transmissions via the wireless transmission link 250 when the downlink transmitter is coupled to the downlink antenna 212. Rather, the operation of the two transceivers 210 and 230 may be coordinated in time such that the downlink receiver is coupled to the downlink antenna 212 for reception of transmissions via the wireless transmission link 250 while the uplink transmitter is coupled to the uplink antenna 232. In some embodiments, there is tight time synchronization with minimal guard times between changes in duplex direction.

[0062] The UE transceiver 230 and the base station transceiver 210 are configured to communicate via a wireless data communication link 250 and to cooperate with an appropriately configured RF antenna arrangement 212 / 232 capable of supporting a specific wireless communication protocol and modulation scheme. In some illustrative embodiments, the UE transceiver 210 and the base station transceiver 210 are configured to support industry standards such as Long Term Evolution (LTE) and emerging 5G standards. However, it should be understood that the present disclosure is not necessarily limited to application to specific standards and related protocols. Instead, the UE transceiver 230 and the base station transceiver 210 can be configured to support alternative or additional wireless data communication protocols, including future standards or variants thereof.

[0063] According to various embodiments, for example, BS 202 may be an evolved Node B (eNB), a serving eNB, a target eNB, a femto station, or a pico station. In some embodiments, UE 204 may be embodied in various types of user equipment, such as a mobile phone, a smart phone, a personal digital assistant (PDA), a tablet, a laptop computer, a wearable computing device, or the like. Processor modules 214 and 236 may be implemented or implemented using a general-purpose processor, a content addressable memory, a digital signal processor, an application specific integrated circuit, a field programmable gate array, any suitable programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof, designed to perform the functions described herein. In this manner, the processor may be implemented as a microprocessor, a controller, a microcontroller, a state machine, or the like. The processor may also be implemented as a combination of computing devices, such as a combination of a digital signal processor and a microprocessor, a plurality of microprocessors, one or more microprocessors in combination with a digital signal processor core, or any other such configuration.

[0064] Furthermore, the steps of the methods or algorithms described in conjunction with the embodiments disclosed herein may be embodied directly in hardware, in firmware, in software modules executed by processor modules 214 and 236, respectively, or in any practical combination thereof. Memory modules 216 and 234 may be implemented as RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. In this regard, memory modules 216 and 234 may be coupled to processor modules 210 and 230, respectively, such that processor modules 210 and 230 may read information from and write information to memory modules 216 and 234, respectively. Memory modules 216 and 234 may also be integrated into their respective processor modules 210 and 230. In some embodiments, each of memory modules 216 and 234 may include a cache memory for storing temporary variables or other intermediate information during the execution of instructions to be executed by processor modules 210 and 230, respectively. Memory modules 216 and 234 may also each include non-volatile memory for storing instructions to be executed by processor modules 210 and 230, respectively.

[0065] The network communication module 218 generally represents the hardware, software, firmware, processing logic, and / or other components of the base station 202 for enabling bidirectional communication between the base station transceiver 210 and other network components and communication nodes configured to communicate with the base station 202. For example, the network communication module 218 can be configured to support Internet or WiMAX services. In a typical deployment, and without limitation, the network communication module 218 provides an 802.3 Ethernet interface so that the base station transceiver 210 can communicate with a conventional Ethernet-based computer network. In this manner, the network communication module 218 can include a physical interface for connecting to a computer network (e.g., a mobile switching center (MSC)). As used herein with respect to a specific operation or function, the terms "configured for," "configured to," and their variations refer to a device, component, circuit, structure, machine, signal, etc. that is physically constructed, programmed, formatted, and / or arranged to perform a specific operation or function.

[0066] The Open Systems Interconnection (OSI) model (referred to herein as the "OSI model") is a concept and logical layout that defines network communications used by systems (e.g., wireless communication devices, wireless communication nodes) that are open to interconnection and communication with other systems. The model is divided into seven subcomponents or layers, each of which represents a conceptual set of services provided to its upper and lower layers. The OSI model also defines a logical network and effectively describes computer packet transmission by using different layer protocols. The OSI model may also be referred to as a seven-layer OSI model or a seven-layer model. In some embodiments, the first layer may be a physical layer. In some embodiments, the second layer may be a media access control (MAC) layer. In some embodiments, the third layer may be a radio link control (RLC) layer. In some embodiments, the fourth layer may be a packet data convergence protocol (PDCP) layer. In some embodiments, the fifth layer may be a radio resource control (RRC) layer. In some embodiments, the sixth layer may be a non-access stratum (NAS) layer or an Internet Protocol (IP) layer, and the seventh layer is another layer. 2. Systems and methods for improving mobility reliability in PSCell addition or change

[0067] Mobility performance can be one of the most important performance indicators of Long Term Evolution (LTE) and Fifth Generation (5G) New Radio (NR). In addition to traditional voice and Internet data services, a variety of innovative services with one or more quality of service (QoS) requirements have emerged in recent years. For example, ultra-reliability and / or low latency are very important for the implementation / performance of modern services (e.g., remote control, aviation, industrial automation, industrial control, augmented reality (AR), virtual reality (VR) services and / or other services). The mobility performance of the above services can be guaranteed with very high reliability (robustness) and very low interruption time. For example, during handover, the delay target of the interruption time can be as small as possible (e.g., close to 0ms or 0ms). Therefore, a mechanism may be needed to improve mobility performance and / or achieve minimum interruption and / or high reliability requirements. The systems and methods proposed herein include new methods for mobility control to, for example, improve / increase mobility performance by at least 25% (e.g., 35, 45 or other percentages). For example, the improvement / increase in mobility performance may result in at least a 25% (eg, 35, 45, or other percentage) improvement in mobility reliability for adding or changing a primary cell (PSCell) in a secondary cell group.

[0068] A wireless communication device (e.g., UE, terminal, or served node) in a wireless communication network can operate in dual connectivity (DC), including intra-E-UTRA DC or multi-radio DC (MR-DC). In the case of intra-E-UTRA DC, the MN (master node, such as Figure 1 BS 102 in) and SN (Secondary Node, such as Figure 1 The BS 102 in the MN may provide / supply E-UTRA access. In the case of MR-DC, the first node may provide / supply NR access, and the second node may provide / supply E-UTRA or NR access. One or more service cells may be configured on the MN and / or SN. The service cells configured on the MN may be defined / designated as a primary cell group (MCG). The service cells configured on the SN may be defined / designated as a secondary cell group (SCG). Each cell group includes at least one primary cell and one or more secondary cells. The primary cell in the MCG may be referred to as a PCell. The primary cell in the SCG may be referred to as a PSCell. When operating in DC, radio bearers (RBs) may be configured to utilize MCG resources and / or SCG resources (e.g., MCG bearers, SCG bearers, and / or split bearers).

[0069] Now refer to Figure 3 , depicts a representation 300 of an example wireless communication environment for a secondary node (SN) change according to some embodiments of the present disclosure. The example environment 300 may include a wireless communication device 304, a primary node (MN) 302A ( Figure 3 MN), a “first” secondary wireless communication node 302B (shown as “MN” in FIG. Figure 3 SN1), and a "second" secondary wireless communication node 302C (shown as "SN1" in FIG. Figure 3 In some embodiments, MN 302A, SN 302B, and / or SN 302C may correspond to a ground terminal, a base station, a gNB, an eNB, or a serving node.

[0070] Cell 303A( Figure 3 Shown as "cell 1"), cell 303B ( Figure 3 ) and cell 303C ( Figure 3 Cell 3 (shown as "Cell 3") is a corresponding cell generated by MN 302A, SN 302B, and SN 302C, respectively. The SCG may include / comprise cell 303B and / or cell 303C, each of which is referred to as a primary SCG cell (PSCell). One or more X interfaces may be deployed / established between MN 302A and SN 302B and SN 302C, respectively. At time T1, wireless communication device 304 may operate with dual connectivity (DC) between MN 302A and SN 302B. As wireless communication device 304 moves, at time T2, the SN may change / switch / adjust from SN 302B to SN 302C. The SN change may be initiated / configured by MN 302A or the source SN.

[0071] In the case of SN change or SN addition, conditional PSCell addition or change (CPAC) may be facilitated to improve / increase / enhance mobility reliability (i.e., mobility robustness). CPAC may include a PSCell addition or change performed / configured by the wireless communication device. The wireless communication device may perform a PSCell addition or change if one or more associated CPAC execution conditions are met / satisfied. The wireless communication device may evaluate / evaluate / assess the CPAC execution conditions in response to receiving / obtaining the CPAC configuration. Once the PSCell addition or change is initiated, the wireless communication device may stop the evaluation of the CPAC execution conditions. The CPAC configuration may include a candidate PSCell configuration generated by the candidate SN and / or corresponding execution conditions (multiple) of the candidate PSCells.

[0072] A. Candidate cell coordination between MN and SN

[0073] a. Coordination of the number of PSCell candidates in the case of CPAC process

[0074] In CPAC, a limited number of candidate PSCells (e.g., up to 8 or another number of candidate PSCells) can be configured. The MN and / or SN can initiate / trigger CPAC. In some embodiments, the number of candidate PSCells configured by the MN and / or SN can be coordinated. The embodiments discussed herein are non-limiting examples describing alternatives and options for coordinating the number of candidate PSCells. The alternatives and options presented herein can be independent processes applicable to one or more embodiments.

[0075] ● Alternative 1: The MN may manage / configure one or more candidate PSCells. In some embodiments, regardless of whether the CPAC is involved in the MN, the MN may generate a final radio resource control (RRC) message (or other message) including the CPAC configuration to the wireless communication device.

[0076] ○MN may send / transmit / broadcast an indication (or other information) to the SN. The indication (or other information) may inform / specify to the SN that the MN generates a final RRC message in one or more CPAC situations. Therefore, the SN may transmit / send / transmit one or more execution conditions and / or CPAC containers including the candidate PSCell configuration to the MN. If the CPAC configuration excludes the MN (e.g., conditional PSCell change within the SN (intra-SN) without the participation of the MN), the MN may still receive / acquire (multiple) execution conditions and / or CPAC containers from the SN. The MN may use at least one of the following options to transmit / send / transmit the indication (or other information). The operations and functions described in these options may be combined with Figure 10-15 Any one or more of the components and / or operations described may be performed.

[0077] ■ Option 1: Xn and / or X2 interface messages may include / specify / provide the indication (e.g., MN-controlled CPAC). For example, the SN (SgNB) Add Request message, the SN (SgNB) Modification Request message, and / or other messages may include the indication as one or more information elements.

[0078] Option 2: The RRC message may include / specify / provide the indication (e.g., MN-controlled CPAC). For example, the CG-ConfigInfo message (or other message) may include the indication. The SN (SgNB) Add Request message, the SN (SgNB) Modify Request message, and / or other messages may include the RRC message as one or more information elements.

[0079] ● Alternative 2: The MN and SN may use / generate / implement an inter-node renegotiation solution to allocate / determine / configure the number of candidate PSCells configured / initiated by the SN.

[0080] ○ The MN may indicate / specify / provide to the SN the maximum number of cells that are allowed to be configured as candidate cells for the CPAC process. The MN may use at least one of the following options to send / transmit an indication specifying the maximum number of PSCells. The operations and functions described in these options may be combined with Figure 10-15 Any one or more of the components and / or operations described may be performed.

[0081] ■ Option 1: The Xn and / or X2 interface message may include / specify / provide the indication (e.g., the maximum number of cells). For example, the SN (SgNB) Add Request message, the SN (SgNB) Modify Request message, and / or other messages may include the indication as one or more information elements.

[0082] Option 2: The RRC message may include / specify / provide the indication (e.g., the maximum number of cells). For example, the CG-ConfigInfo message (or other message) may include the indication. The SN (SgNB) Add Request message, the SN (SgNB) Modify Request message, and / or other messages may include the RRC message as one or more information elements.

[0083] In some embodiments, the SN may request one or more additional candidate cells from the MN. Thus, the SN may request the MN to indicate the number of cells that are allowed to be configured as reference candidate cells for the CPAC process. The SN may use at least one of the following options to send / transmit an indication of the reference number of PSCells. The operations and functions described in these options may be combined with Figure 10-15 Any one or more of the components and / or operations described may be performed.

[0084] Option 1: Xn and / or X2 interface messages may include the indication (e.g., the requested number of cells). For example, the SN (SgNB) Add Request Confirm message, the SN (SgNB) Modify Request Confirm message, the SN (SgNB) Modify Required message, and / or other messages may include the indication as one or more information elements.

[0085] Option 2: The RRC message may include the indication (e.g., the requested number of cells). For example, the CG-Config message (or other message) may include the indication. The SN (SgNB) Add Request Confirm message, the SN (SgNB) Modify Request Confirm message, the SN (SgNB) Modify Required message, and / or other messages may include the RRC message as one or more information elements.

[0086] In some embodiments, the MN may accept / approve the referenced number of cells in the request from the SN. If the MN denies / rejects the referenced number of cells, the MN may deny / reject the received Xn or X2 interface message.

[0087] The candidate number of cells for the SN may be considered using at least one of the following options:

[0088] ■ Option 1: Candidate cells for the CPAC process initiated by the SN.

[0089] ■ Option 2: Candidate cells for the CPAC procedure whose final CPAC command may be generated by the SN. This option may be applied to conditional PSCell change (CPC) within a SN without MN participation.

[0090] ● Alternative solution 3: The MN may directly indicate / specify / provide the SN with the number of PSCell candidates allowed to be configured / initiated.

[0091] The MN may indicate / specify / provide to the SN the maximum number of cells that are allowed to be configured as candidate cells for the CPAC process. The MN may send / transmit the indication specifying the maximum number of PSCells using at least one of the following options:

[0092] ■ Option 1: Xn and / or X2 interface messages may include the indication (e.g., the maximum number of cells). For example, an SN (SgNB) Add Request message, an SN (SgNB) Modify Request message, and / or other messages may include the indication as one or more information elements.

[0093] Option 2: The RRC message may include the indication (e.g., the maximum number of cells). For example, the CG-ConfigInfo message (or other message) may include the indication. The SN (SgNB) Add Request message, the SN (SgNB) Modify Request message, and / or other messages may include the RRC message as one or more information elements.

[0094] b. Coordination of the number of candidate cells in the coexistence of conditional handover (CHO) and CPAC

[0095] In some embodiments, the maximum number of candidate cells for the target PCell and PSCell can be limited (for example, up to 8 or other number of candidate cells). Therefore, if the CPAC and CHO processes are configured at the same time, the MN and SN can coordinate / configure the number of candidate cells. The MN can configure / control / determine the candidate number of PCell for CHO and / or the candidate number of PSCell for CPAC initiated by the MN. The SN can configure the candidate number of PSCell for CPAC initiated by the SN. Therefore, if CHO and CPAC are configured at the same time, one or more of the aforementioned solutions for candidate PSCell coordination can be used for candidate cell (for example, including both PCell and PSCell) coordination. In some embodiments, for the coexistence of CHO and CPAC, the candidate PCell and / or PSCell configurations can be encapsulated in the same / corresponding conditional reconfiguration container. The candidate number of cells in the reconfiguration container can correspond to 2 (or other number).

[0096] B. Inter-node interactions during the CPAC preparation phase

[0097] a. Notify the target SN of the maximum number of candidate PSCells allowed to be configured

[0098] During inter-SN CPAC, the target SN may select / identify / specify a target PSCell. The target SN may select a candidate PSCell using one or more measurement results related to the target SN. The MN and / or the source SN may provide / specify (multiple) measurement results to the target SN. The MN and / or the SN may provide one or more measurement results of one or more candidate cells. Thus, the target SN may select one or more cells to be configured as candidate PSCells in one round of SN addition. The source SN and / or the MN may indicate / provide / specify the maximum number of candidate PSCells configured by the target SN when requesting CPAC for the target SN (e.g., sending / transmitting an SN (SgNB) add request message to the target SN).

[0099] One or more procedures may be configured to indicate the maximum number of candidate PSCells to the target SN.The embodiments discussed herein are non-limiting examples describing one or more procedures.

[0100] ● For MN-initiated CPAC, the MN may decide / determine the maximum number of candidate PSCells configured / determines by the target SN. The MN may send / transmit an indication to inform the target SN of the determination. The MN may use at least one of the following options to send / transmit the indication to the target SN. The operations and functions described in these options may be combined with Figure 10 and Figure 11 Any one or more of the components and / or operations described, such as operations 210 and 310, may be performed.

[0101] Option 1: The Xn and / or X2 interface message may include the indication (e.g., the maximum number of candidate PSCells). For example, the SN (SgNB) Add Request message and / or other messages may include the indication as one or more information elements.

[0102] Option 2: The RRC message may include the indication (e.g., the maximum number of candidate PSCells). For example, the CG-ConfigInfo message (or other message) may include the indication. The SN (SgNB) Add Request message and / or other messages may include the RRC message as one or more information elements.

[0103] ●For CPAC initiated by SN, one or more alternatives can be considered.

[0104] ○ Alternative 1: The source SN may decide / determine the maximum number of candidate PSCells to be configured by the target SN. The source SN may send / transmit an indication to inform the MN of the determination. The MN may send / transmit / broadcast the indication to the target SN. The indication may be similar to the indication corresponding to the CPAC procedure initiated by the MN. The source SN and / or the MN may send / transmit the indication using at least one of the following options. The operations and functions described in these options may be combined with Figure 12 、 Figure 13 and Figure 14 Any one or more of the components and / or operations described, such as operations 410, 510, and 610, may be performed.

[0105] ■ Option 1: Xn and / or X2 interface messages may include the indication (e.g., the maximum number of candidate PSCells). For example, the SN (SgNB) Change Required message and / or other messages may include the indication as one or more information elements.

[0106] ■ Option 2: The RRC message may include the indication (e.g., the maximum number of candidate PSCells). For example, the CG-Config message (or other message) may include the indication. The SN (SgNB) Change Required message and / or other messages may include the RRC message as one or more information elements.

[0107] ○ Alternative Solution 2: The MN may decide / determine the maximum number of candidate PSCells to be configured by the target SN. The MN may send / transmit / broadcast this indication to the target SN. This indication may be similar to the indication corresponding to the CPAC procedure initiated by the MN. The operations and functions described in this alternative solution may be combined with Figure 12 、 Figure 13 and Figure 14 Any one or more of the components and / or operations described, such as operations 420, 520, and 620, may be performed.

[0108] b. Notify the source SN of CPAC related information

[0109] In some embodiments of the MN-initiated SN change procedure, the MN may initiate / trigger an SN release procedure to release / make available the source SN resources (e.g., sending / transmitting an SN (SgNB) Release Request message to the source SN). The MN may initiate the SN release procedure in response to completing / finalizing the SN add procedure (e.g., receiving / obtaining an SN (SgNB) Add Request Confirmation message from the target SN). The source SN may receive / obtain an SN (SgNB) Release Request message (or other message). In response to receiving the Release Request message, the source SN may stop providing user data (or other information) to the wireless communication device. For conditional SN changes, the wireless communication device may maintain data transmission and / or reception with the source SN until one or more execution conditions are met. For example, the wireless communication device may continue data transmission and / or reception with the source SN upon receiving / obtaining one or more CPAC commands. Thus, the MN may initiate / trigger the SN release procedure in response to confirming the completion of CPAC execution (e.g., successful completion of random access to the target PSCell).

[0110] In some embodiments, the MN may enable early data forwarding for a bearer terminated at an SN. In this case, the MN may provide / indicate / specify a data forwarding address to the source SN. The MN may inform / specify the data forwarding address in connection with the CPAC procedure. The MN may provide the data forwarding address in response to completing / finalizing the SN add procedure.

[0111] In some embodiments, one or more procedures (e.g., a CPAC procedure initiated by the MN) may be used / enabled / implemented to transmit / send / transmit data forwarding information to the source SN. Data forwarding information (e.g., forwarding address, transport layer address, and / or other information) may be transmitted in response to completing the SN add procedure. The embodiments discussed herein are non-limiting examples describing one or more procedures.

[0112] ● Step 1: If data forwarding is enabled, the MN may send / transmit / deliver a message to provide data forwarding information to the source SN. The message may include an indication for specifying that the process is a CPAC-based process. The MN may send / transmit the indication to the source SN using at least one of the following options. The operations and functions described in these options may be combined with Figure 10 、 Figure 13 and Figure 14 Any one or more of the components and / or operations described, such as operations 220, 540, and 640, may be performed.

[0113] Option 1: An Xn or X2 interface message (or other message) may include the indication. For example, an Xn-U address indication message, a data forwarding address indication message, and / or other messages may include the CPAC indicator as one or more information elements.

[0114] Option 2: An Xn or X2 interface message may include this indication as a "cause" value (or other value). For example, an Xn-U Address Indication message, a Data Forwarding Address Indication message, and / or other messages may include / specify a "cause" value. The "cause" value may be set / modified to indicate / specify "conditional SN mobility."

[0115] ● Step 2: In response to receiving / obtaining the message, the source SN may perform / enable early data forwarding for the bearer terminated at the SN. In some embodiments, the source SN may send / transmit an early state transfer message (or other message) to the source MN and / or the target SN.

[0116] In some embodiments of the SN-initiated SN change procedure, the MN may confirm the release of the source SN resources by sending / transmitting an SN (SgNB) change confirmation message (or other message) to the source SN. The MN may send / transmit this message in response to the successful allocation of the target SN resources (e.g., receiving / obtaining an RRCReconfigurationComplete message from the wireless communication device). In response to receiving the SN (SgNB) change confirmation message, the source SN may stop providing user data (or other information) to the wireless communication device. For conditional SN changes, the wireless communication device may maintain data transmission and / or reception with the source SN until one or more execution conditions are met. For example, the wireless communication device may continue data transmission / reception with the source SN upon receiving / obtaining one or more CPAC commands. Thus, the MN may indicate / inform / specify to the source SN that the release of resources is enabled by a CPAC-based procedure. The SN may continue to provide user data (or other information) to the wireless communication device.

[0117] In some embodiments, one or more procedures (e.g., SN-initiated CPAC procedures) may be used / enabled / implemented to inform the source SN of the CPAC-based procedures in the SN change confirmation. The embodiments discussed herein are non-limiting examples describing one or more procedures.

[0118] ● Step 1: In the SN change confirmation, the MN may send / transmit the indication to the source SN. The indication may specify / inform that the process is a CPAC-based process. The MN may send / transmit the indication to the source SN using at least one of the following options. The operations and functions described in these options may be combined with Figure 12 and Figure 13Any one or more of the components and / or operations described, such as operations 440 and 590, may be performed.

[0119] Option 1: The Xn or X2 interface message (or other message) may include the indication. For example, the SN (SgNB) change confirmation message and / or other messages may include the CPAC indicator as one or more information elements.

[0120] Option 2: The SN (SgNB) Change Confirm message (or other message) may include this indication as a "Cause" value (or other value). For example, the "Cause" value may be set / modified to indicate / specify "Conditional SN Mobility".

[0121] Option 3: The RRC message (or other message) may include / specify the indication. For example, the CG-ConfigInfo message may include the indication. The SN (SgNB) Change Confirmation message (or other message) may include the RRC message as one or more information elements.

[0122] ● Step 2: In response to receiving / obtaining the SN (SgNB) change confirmation message with this indication, the source SN may continue to provide user data (or other information) to the wireless communication device. In some embodiments, if applicable, the source SN may initiate data forwarding.

[0123] In some embodiments of the SN-initiated conditional SN change procedure, the target SN may provide the identification information of the selected candidate PSCell to the MN. The target SN may provide the identification information via the SN (SgNB Add Request Confirmation) message (see Figure 12 、 Figure 13 and Figure 14 The target SN may provide identification information in response to completing / finalizing the candidate PSCell configuration. The MN may send / transmit / transmit the PSCell identification information to the source SN for subsequent candidate PSCell control.

[0124] One or more procedures (eg, SN initiated conditional SN change) may be configured / enabled / implemented / used to inform the source SN of the identification information of the selected candidate PSCell. The embodiments discussed herein are non-limiting examples describing one or more procedures.

[0125] ● Alternative 1: The MN may send / transmit PSCell identification information and / or PSCell identification information list to the source SN. The MN may send this information via a message to provide / specify / indicate data forwarding information. The operations and functions described in the following options may be combined with Figure 13 and Figure 14Any one or more of the components and / or operations described, such as operations 540 and 640, may be performed.

[0126] Option 1: Xn or X2 interface messages may include / provide / specify PSCell identification information. For example, an Xn-U address indication message, a data forwarding address indication message, and / or other messages may include PSCell identification information as one or more information elements.

[0127] Option 2: The RRC message may include / provide / specify PSCell identification information. For example, the CG-ConfigInfo message may include PSCell identification information. The Xn-U Address Indication message, the Data Forwarding Address Indication message, and / or other messages may include the RRC message as one or more information elements.

[0128] ● Alternative 2: The MN may send / transmit PSCell identification information and / or PSCell identification information list to the source SN. The MN may send this information via a message to confirm the successful allocation of target SN resources and / or the release of source SN resources. The operations and functions described in the following options may be combined with Figure 12 Any one or more of the components and / or operations described may be performed, such as operation 440 .

[0129] Option 1: Xn or X2 interface messages may include / provide / specify PSCell identification information. For example, the SN (SgNB) change confirmation message and / or other messages may include PSCell identification information as one or more information elements.

[0130] Option 2: The RRC message may include / provide / specify PSCell identification information. For example, the CG-ConfigInfo message may include PSCell identification information. The SN (SgNB) Change Confirm message and / or other messages may include the RRC message as one or more information elements.

[0131] The PSCell identification information may be indicated / specified using one or more of the following options:

[0132] Option 1: The PSCell identification information may be indicated using the frequency of the PSCell (or other frequencies).

[0133] ○ Option 2: The PSCell identification information may be indicated using the frequency and / or Physical Cell Identity (PCI) of the PSCell.

[0134] Option 3: The PSCell identification information may be indicated using the Cell Global Identifier (CGI) (or other identifiers) of the PSCell.

[0135] In some embodiments, the source SN may add, modify and / or release one or more execution conditions for each PSCell identification information (e.g., for each frequency, for each PCI and frequency, and / or other information). The source SN may add, modify and / or release (multiple) execution conditions in response to receiving / obtaining candidate PSCell identification information. The source SN may send / transmit / transmit one or more execution conditions to the MN through an SN modification procedure initiated by the initiating SN. The source SN may provide / specify (multiple) execution conditions for each PSCell identification information via a message (e.g., an SN (SgNB) modification request message or other message). The source SN may use one or more options to provide (multiple) execution conditions.

[0136] Option 1: An Xn or X2 interface message may include / provide / specify execution condition(s). For example, an SN (SgNB) Modification Required message and / or other messages may include execution condition(s) as one or more information elements.

[0137] Option 2: The RRC message may include / provide / specify execution condition(s). For example, the CG-Config message may include execution condition(s). The SN (SgNB) Modification Required message and / or other messages may include the RRC message as one or more information elements.

[0138] c. Associate relevant execution conditions with candidate PSCells

[0139] The MN and / or SN may initiate / trigger a conditional PSCell change. The MN and / or SN may provide / indicate measurement results related to the target SN when requesting CPAC for the target SN. The target SN may simultaneously select / identify candidate PSCells having relevant measurement results provided / specified by the MN and / or SN (e.g., PSCell information may be included in candidateCellInfoListMN and candidateCellInfoListSN). In the above case, the MN and / or source SN may provide / specify / indicate (multiple) execution conditions for each cell. Therefore, one or more methods for linking / associating (multiple) execution conditions to candidate PSCells may be considered. For example, the method may include including (multiple) corresponding execution conditions in the final RRC message for the CPAC process. In some embodiments, one or more options for including (multiple) execution conditions may be utilized.

[0140] • Option 1: The final RRC message for CPAC may include / indicate execution condition(s) generated by the MN or SN. The MN may determine one or more execution conditions to be included in the message.

[0141] • Option 2: The final RRC message for CPAC may include / indicate execution condition(s) generated simultaneously by the MN and the SN.

[0142] c. Instruct the candidate SN to release candidate PSCell resources when CPAC is executed

[0143] In CPAC, the wireless communication network can configure one or more candidate SNs. In some embodiments, the wireless communication device can select, identify, or designate at least one candidate PSCell to perform a random access procedure toward the target SN. Therefore, the mobile network can notify, instruct, or command one or more candidate SNs to release reserved candidate PSCell resources, thus avoiding resource waste.

[0144] The wireless communication device may send a first RRCReconfigurationComplete message (or other message) to the MN in response to receiving / obtaining an RRCReconfiguration message (or other message) including a CPAC configuration. During the execution of CPAC (e.g., one or more CPAC execution conditions are met), the wireless communication device may send / transmit a second RRCReconfigurationComplete message, a ULInformationTransferMRDC message, and / or other messages to the MN. The (multiple) second messages may include an embedded RRCReconfigurationComplete message (or other message) to the SN. In some embodiments, if configured, the wireless communication device may send / transmit a second RRCReconfigurationComplete message (or other message) to the target SN via a single radio bearer three (SRB3).

[0145] Depending on whether CPAC is involved / related / associated with MN and / or SRB3 configuration, at least two cases and / or alternatives may be considered / evaluated. The embodiments discussed herein are non-limiting examples describing at least two cases / alternatives. The operations and functions described in these cases / alternatives may be combined with Figure 10 、 Figure 11 、 Figure 12 、 Figure 13 and Figure 14 Any one or more of the components and / or operations described, such as operations 2120 to 2140, 3110, 4130 to 4160, 5140 to 5170, and 6130 to 6150, may be performed.

[0146] Case 1: The wireless communication device may select / identify a candidate PSCell whose CPAC configuration is related / associated / related to the MN (e.g., an inter-SN candidate PSCell). In some embodiments, the wireless communication device may select / identify a candidate PSCell whose CPAC configuration is not related / associated / related to the MN (e.g., an intra-SN CPC without MN participation) and has no SRB3 configuration. At least two alternatives may be considered / used to notify one or more candidate SNs.

[0147] ○ Alternative Solution 1: The MN may notify / instruct / command one or more candidate SNs to release resources reserved for the CPAC via a new Xn or X2 interface message (e.g., a CPAC Cancel message) or other message. If the selected / identified PSCell is different from the candidate PSCell within the SN, the MN may send / transmit an SN Release message (or other message) to the source SN. The MN may notify the candidate SNs and / or send a Release message to the source SN in response to receiving / obtaining a second RRCReconfigurationComplete message, a ULInformationTransferMRDC message, and / or other message from the wireless communication device.

[0148] ○Alternative 2: The target SN may send / transmit a new Xn or X2 interface message (e.g., a CPAC success message) to inform the MN of the successful completion of CPAC. The target SN may send / transmit identification information of the target PSCell (e.g., target PSCell frequency and PCI, CGI, and / or other information) to the MN. The target SN may send the message and / or information in response to the completion of random access to the target PSCell. In some embodiments, the MN may notify / inform one or more candidate SNs to release resources reserved for CPAC via a new Xn or X2 interface message (e.g., a CPAC cancellation message) or other message. If the selected / identified PSCell is different from the candidate PSCell within the SN, the MN may send an SN release message (or other message) to the source SN. The MN may inform the candidate SN and / or send a release message to the source SN in response to receiving / obtaining an Xn or X2 interface message from the target SN.

[0149] ● Case 2: The wireless communication device may select / identify a candidate PSCell whose CPAC configuration is not related / independent / unassociated with the MN (eg, no intra-SN CPC in which the MN participates) and has an SRB3 configuration. At least three alternatives may be considered / used to inform the MN.

[0150] ○Alternative 1: The wireless communication device may send / transmit identification information of the target PSCell (e.g., target PSCell frequency and PCI, candidate cell ID, candidate conditional reconfiguration index, and / or other information) to the MN via an RRC message (e.g., an RRCReconfigurationComplete message or other message). The wireless communication device may send this information in response to the completion of random access to the target PSCell. In some embodiments, the MN may notify / inform one or more candidate SNs to release resources reserved for CPAC via a new Xn or X2 interface message (e.g., a CPAC Cancel message) or other message. The MN may inform the candidate SNs in response to receiving / obtaining an RRC message from the wireless communication device.

[0151] ○Alternative 2: The wireless communication device may send / transmit identification information of the target PSCell (e.g., target PSCell frequency and PCI, candidate cell ID, candidate conditional reconfiguration index and / or other information) to the MN via an RRC message (e.g., an RRCReconfigurationComplete message or other message). The wireless communication device may send this information in response to a trigger of CPAC execution (e.g., at least one CPAC execution condition is met / satisfied). In some embodiments, the MN may notify / inform one or more candidate SNs to release resources reserved for CPAC via a new Xn or X2 interface message (e.g., a CPAC cancel message) or other message. The MN may inform the candidate SNs in response to receiving / obtaining an RRC message from the wireless communication device.

[0152] ○Alternative 3: The SN may send a new Xn or X2 message (e.g., a CPAC success message or other message) to inform the MN of the successful completion of the CPAC. The SN may send identification information of the target PSCell (e.g., target PSCell frequency and PCI, CGI, and / or other information) to the MN. The SN may send the message and / or the information in response to receiving / obtaining an RRCReconfigurationComplete message via SRB3. In some embodiments, the MN may notify / inform one or more candidate SNs to release resources reserved for CPAC via a new Xn or X2 interface message (e.g., a CPAC cancel message) or other message. The MN may inform the candidate SNs in response to receiving / obtaining an Xn or X2 interface message from the target SN.

[0153] The PSCell identification information may be sent / transmitted / delivered to the MN using at least one of the following options:

[0154] Option 1: The Xn or X2 interface message (or other message) may include / provide / specify the target PSCell identification information. For example, the CPAC success message (or other message) may include the PSCell identification information as one or more information elements.

[0155] ○ Option 2: RRC message (eg, CG-Config message or other message) may include / provide / specify target PSCell identification information. In some embodiments, the CPAC success message (or other message) may include the RRC message as one or more information elements.

[0156] D. Modify or cancel the configured candidate PSCell

[0157] In some embodiments, both the initiating node (e.g., the MN and / or the source SN) and the target node (e.g., the target SN) can trigger / initiate modification and / or cancellation of the CPAC configuration. If the node receives updated measurement results related to / associated with the target SN from the wireless communication device, the initiating node can trigger / initiate modification and / or cancellation. In some embodiments, the CPAC modification and / or cancellation process can be performed using at least one of the following alternatives. The embodiments discussed herein are non-limiting examples describing alternatives.

[0158] ● Alternative Solution 1: The initiating node may decide / determine to modify / cancel one or more configured candidate PSCells based on the updated measurement results. The initiating node may inform / instruct / command the target SN to modify / cancel the CPAC configuration of the relevant PSCell (e.g., triggering a CPAC modification / cancellation procedure initiated by the initiating node). The message may include an instruction to the target SN specifying the PSCell information to be modified / cancelled (e.g., frequency, frequency and PCI, CGI, and / or other information).

[0159] ●Alternative Solution 2: The initiating node may send / transmit the updated measurement results (e.g., candidateCellInfoListMN, candidateCellInfoListSN, and / or other information) to the target SN. In some embodiments, the target SN may modify / cancel the configured candidate PSCells on its own (e.g., triggering a CPAC modification / cancellation procedure initiated by the target SN).

[0160] In some embodiments, the initiating node may correspond to the source SN. Thus, the source SN may send / transmit information to the target SN via the MN.

[0161] In the case of CPAC modification initiated by an initiating node, the CPAC modification and / or cancellation process may be performed using at least one of the following alternatives. The embodiments discussed herein are non-limiting examples describing the alternatives.

[0162] ●Alternative 1: The initiating node can request to modify the CPAC configuration.

[0163] The initiating node may send / transmit an Xn or X2 interface message (e.g., a CPAC modification request message or other message) to the target SN to request modification of the CPAC configuration. The message may include measurement results related to / associated with the target SN, the updated source secondary cell group (SCG) configuration, identification information of the PSCell to be modified (e.g., frequency, frequency and PCI, or CGI), and / or other information.

[0164] In some embodiments, the initiating node may correspond to a source SN. Therefore, the source SN may send / transmit this message (e.g., an SN change request message, a CPAC modification request message, or other message) to the mobile node. The mobile node may transmit / transmit this message to the target SN to request modification / cancellation of the CPAC configuration of the associated PSCell.

[0165] • Alternative 2: The initiating node may request to release the previous CPAC configuration and add the new CPAC configuration (eg, replace the previous CPAC configuration with the new CPAC configuration).

[0166] Step 1: The initiating node may send / transmit an Xn or X2 interface message (e.g., a CPAC cancel message) or other message to the target SN to release the CPAC configuration of the relevant PSCell. The message may include identification information (e.g., frequency, frequency and PCI, CGI, or other information) of the PSCell to be released / modified, and / or an indication that the release process is related / associated with CPAC modification.

[0167] Step 2: The initiating node may send an Xn or X2 interface message (e.g., an SN add request message and / or an SN change request message) or other message to the target SN to request a new CPAC configuration for the associated PSCell. The message may include identification information of the PSCell to be added / modified (e.g., frequency, frequency and PCI, CGI, and / or other information), the updated source SCG configuration, updated measurement results related / associated with the target SN (e.g., candidateCellInfoListMN, candidateCellInfoListSN, and / or other information), and / or an indication that the addition process is related to CPAC modification.

[0168] ○ The indication specifying that the release / addition process is related to CPAC modification may be transmitted / sent to the target SN using at least one of the following options:

[0169] ■Option 1: The Xn or X2 interface message may include the indication (e.g., including CPAC replacement) as one or more information elements in the SN (SgNB) Add Request message, SN (SgNB) Change Required message, CPAC Cancel message, and / or other messages.

[0170] ■Option 2: The Xn or X2 interface message may include this indication as a “cause” value (e.g., setting the “cause” value to CPAC replacement) in the SN (SgNB) add request message, SN (SgNB) change required message, CPAC cancel message, and / or other messages.

[0171] In some embodiments, the initiating node may correspond to a source SN. Therefore, the source SN may send / transmit / deliver a message (e.g., an SN change request message, a CPAC cancellation message, or other message) to the MN. The MN may send a message (e.g., an SN add request message, a CPAC cancellation message, or other message) to the target SN to request modification / cancellation of the CPAC configuration of the associated / associated PSCell.

[0172] a. Example 1: MN-initiated CPAC modification

[0173] Now refer to Figure 4 , depicts a communication diagram of an embodiment of a process 400 for CPAC modification initiated by MN 402. An embodiment of process 400 may be used for Alternative 1 described above. Under process 400, MN 402 may send / transmit / transmit a CPAC modification request message (610) to target SN 404. The CPAC modification request message (or other message) may specify / provide a request to modify the CPAC configuration of one or more candidate PSCells. The message may include measurement results related to the target SN 404, the source SCG configuration, identification information of the PSCell to be modified (e.g., frequency, frequency and PCI, and / or CGI), and / or other information. SN 404 may send / transmit a CPAC modification request confirmation message (or other message) (620) to MN 402. The CPAC modification request confirmation message (or other message) may include the updated CPAC configuration of the relevant candidate PSCells.

[0174] b. Example 2: MN-initiated CPAC modification

[0175] Now refer to Figure 5, depicts a communication diagram of an embodiment of a process 500 for CPAC modification initiated by MN 502. Embodiments of process 500 may be used in alternative 2 described above. Under process 500, MN 502 may send / transmit / transmit a CPAC cancel message (710) to target SN 504. In response to receiving the message, target SN 504 may release the CPAC configuration of the PSCell to be modified. The message may include identification information (e.g., frequency, frequency and PCI, and / or CGI) of the PSCell to be released / modified, an indication (e.g., an indication specifying that the release process is related to the CPAC configuration), and / or other information.

[0176] In some embodiments, the MN 502 may send / transmit an X2 or Xn interface message (e.g., an SN add request message) (720) to the target SN 504. The SN add request message (or other message) may provide / specify a request for a new CPAC configuration for the associated PSCell. The message may include identification information (e.g., frequency, frequency and PCI, and / or CGI) of the PSCell to be added / modified, an updated SCG configuration, updated measurement results associated with the target SN 504 (e.g., candidateCellInfoListMN, candidateCellInfoListSN, or other results), an indication (e.g., an indication specifying that the addition process is associated with a CPAC modification), and / or other information. The target SN 504 may send / transmit an SN add request message (730) to the MN 502. The message may include the updated CPAC configuration for the associated candidate PSCell.

[0177] c. Example 3: CPAC modification initiated by the source SN

[0178] Now refer to Figure 6 , depicts a communication diagram of an embodiment of a process 600 for CPAC modification initiated by a source SN 604. Embodiments of process 600 may be used in alternative 1 described above. Under process 600, the source SN 604 may send / transmit a message (e.g., an SN change request message, a CPAC modification request message, and / or other message) to the MN 602 (810). The message may provide / specify a request to modify the CPAC configuration of one or more candidate PSCells. The message may include measurement results related to the target SN 606, the source SCG configuration, identification information of the PSCell to be modified (e.g., frequency, frequency and PCI, and / or CGI), and / or other information.

[0179] In some embodiments, the MN 602 sends / transmits a CPAC Modification Request message (or other message) (820) to the target SN 606. The message may provide a request to modify the CPAC configuration of one or more candidate PSCells. The message may include measurement results related to the target SN 606, the source SCG configuration, identification information of the PSCell to be modified (e.g., frequency, frequency and PCI, and / or CGI), and / or other information. The target SN 606 may send / transmit a CPAC Modification Request Acknowledgement message (or other message) (830) to the MN 602. The message may include the updated CPAC configuration of the relevant candidate PSCells, and / or other information.

[0180] d. Example 4: CPAC modification initiated by the source SN

[0181] Now refer to Figure 7 , depicts a communication diagram of an embodiment of a process 700 for CPAC modification initiated by a source SN 704. Embodiments of the process 700 may be used for Alternative 2 described above. Under the process 700, the source SN 704 may send / transmit a message (e.g., a CPAC cancel message, an SN change request message, and / or other message) to the MN 702 (910). The message may provide a request to release the CPAC configuration of the PSCell to be modified. The message may include identification information of the PSCell to be modified (e.g., frequency, frequency and PCI, and / or CGI), an updated source SCG configuration, updated measurement results associated with the target SN 706 (e.g., candidateCellInfoListMN, candidateCellInfoListSN, and / or other results), an indication (e.g., an indication specifying that the process is related to CPAC modification), and / or other information.

[0182] In some embodiments, the MN 702 may send / transmit a CPAC cancellation message (or other message) (920) to the target SN 706. In response to receiving the message, the target SN 706 may release the CPAC configuration of the PSCell to be modified. The message may include identification information (e.g., frequency, frequency and PCI, and / or CGI) of the PSCell to be released / modified, an indication (e.g., an indication specifying that the release process is related to CPAC modification), and / or other information.

[0183] MN 702 may send an SN add request message (or other message) to target SN 706 (930). The message may provide a request for a new CPAC configuration for the associated PSCell. The message may include identification information of the PSCell to be added / modified (e.g., frequency, frequency and PCI, and / or CGI), an updated source SCG configuration, updated measurement results associated with target SN 706 (e.g., candidateCellInfoListMN, candidateCellInfoListSN, and / or other results), an indication (e.g., an indication specifying that the addition process is associated with CPAC modification), and / or other information. Target SN 706 may send / transmit an SN add request confirmation message (or other message) to MN 702 (940). The message may include the updated CPAC configuration for the associated candidate PSCell, and / or other information.

[0184] At least one of the following alternatives may be used to perform CPAC modification initiated by the target SN: The embodiments discussed herein are non-limiting examples describing the alternatives.

[0185] ●Alternative 1: The target SN may request to modify the CPAC configuration.

[0186] The target SN may send / transmit an Xn or X2 interface message (e.g., a CPAC modification message or other message) to the MN to request modification of the CPAC configuration of the relevant PSCell. The message may include the updated CPAC configuration, identification information of the PSCell to be modified (e.g., frequency, frequency and PCI, or CGI), and / or other information.

[0187] ● Alternative 2: The target SN may request the MN to cancel / remove the previous CPAC configuration of the relevant PSCell. The MN may request the target SN to add a new CPAC configuration for the relevant PSCell (eg, replace the previous CPAC configuration with the new CPAC configuration).

[0188] Step 1: The target SN may send / transmit an Xn or X2 interface message (e.g., a CPAC cancel message) or other message to the MN to release the CPAC configuration of the relevant PSCell. The message may include identification information (e.g., frequency, frequency and PCI, CGI, or other information) of the PSCell to be released / modified, and / or an indication that the release procedure is related / associated with CPAC modification.

[0189] Step 2: The MN may send an Xn or X2 interface message (e.g., an SN Add Request message) or other message to the target SN to request a new CPAC configuration for the associated PSCell. The message may include identification information of the PSCell to be added / modified (e.g., frequency, frequency and PCI, CGI, and / or other information), the updated source SCG configuration, updated measurement results related / associated with the target SN (e.g., candidateCellInfoListMN, candidateCellInfoListSN, and / or other information), and / or an indication that the addition procedure is related to CPAC modification.

[0190] o The indication specifying that the release / addition procedure is related to CPAC modification may be transmitted / sent to the MN and / or the target SN using at least one of the following options:

[0191] ■Option 1: Xn or X2 interface message may include the indication (e.g., including CPAC replacement) as one or more information elements in the SN (SgNB) add request message, CPAC cancel message, and / or other messages.

[0192] ■Option 2: The Xn or X2 interface message may include this indication as a “cause” value (e.g., setting the “cause” value to CPAC replacement) in the SN (SgNB) add request message, CPAC cancel message, and / or other messages.

[0193] e. Example 5: CPAC modification initiated by the target SN

[0194] Now refer to Figure 8 , depicts a communication diagram of an embodiment of a process 800 for CPAC modification initiated by a target SN 804. Embodiments of process 800 may be used in alternative 1 described above. Under process 800, the target SN 804 may send / transmit a CPAC modification request message (or other message) to the MN 802 (1010). The message may provide a request to modify the CPAC configuration of the associated PSCell. The message may include the updated CPAC configuration, identification information of the PSCell to be modified (e.g., frequency, frequency and PCI, and / or CGI), and / or other information. The MN 802 may send / transmit a CPAC modification request confirmation message to the target SN 804 to confirm the modification (1020).

[0195] f. Example 6: CPAC modification initiated by the target SN

[0196] Now refer to Figure 9, depicts a communication diagram of an embodiment of a process 900 for CPAC modification initiated by a target SN 904. Embodiments of process 900 may be used in alternative 2 described above. Under process 900, the target SN 904 may send / transmit a CPAC cancel message (or other message) to the MN 902 (1110). The message may provide a request to release the CPAC configuration of the associated PSCell. The message may include identification information (e.g., frequency, frequency and PCI, and / or CGI) of the PSCell to be released / modified, an indication specifying that the release process is associated with CPAC modification, and / or other information.

[0197] In some embodiments, the MN 902 may send an SN Add Request message (or other message) to the target SN 904 (1120). The message may provide a request for a new CPAC configuration for the associated PSCell. The message may include information indicating the PSCell to be added / modified (e.g., frequency, frequency and PCI, and / or CGI), an updated source SCG configuration, updated measurement results associated with the target SN 904 (e.g., candidateCellInfoListMN, candidateCellInfoListSN, and / or other results), an indication (e.g., an indication specifying that the addition process is associated with a CPAC modification), and / or other information. The target SN 904 may send an SN Add Request Acknowledge message (or other message) to the MN 902 (1130). The message may include the updated CPAC configuration for the associated candidate PSCell.

[0198] E. Handling stored CPAC configuration in case of PCell changes

[0199] In CPAC, the network may send / transmit a PCell change command (e.g., an RRCReconfiguration message) to the wireless communication device. The network may send the command before the execution condition(s) of CPAC are met. In some embodiments, the wireless communication device may immediately perform / execute the PCell change. The execution of the PCell change may affect the stored configuration of the wireless communication device. Therefore, one or more methods for performing the PCell change and processing the CPAC configuration stored by the wireless communication device may be considered.

[0200] In some embodiments, the wireless communication device may delete / remove the CPAC configuration in response to a PCell change. In a PCell change without SN participation (e.g., an intra-MN PCell change without a PSCell change), the stored CPAC configuration may be used after the PCell change is completed. In some embodiments, the SN may not be aware of the PCell change process. Therefore, the SN may not know whether the stored CPAC configuration is released by the wireless communication device. A configuration mismatch between the SN and the wireless communication device may cause subsequent configuration failures. Therefore, an information exchange process may be required / enabled / implemented (e.g., using X2 or Xn interface messages or other messages) to inform the SN of the performed PCell change. The information exchange process can be used for PCell changes without SN participation. The network can configure the release of the stored CPAC configuration (e.g., in response to a PCell change) to avoid unnecessary release of the CPAC configuration.

[0201] The network (e.g., source / target MN and / or source SN) may send / transmit an indicator to the wireless communication device via a dedicated RRC message (e.g., RRCReconfiguration message) and / or broadcast signaling (e.g., system information block). This indicator may cause the wireless communication device to maintain / store the CPAC configuration in response to the PCell change. For example, the RRCReconfiguration message and / or system information block message (or other message) may include the indicator as one or more information elements. In another example, the conditionalReconfiguration IE in the RRCReconfiguration message may include the indicator as one or more information elements.

[0202] In some embodiments, inter-node interactions may be used to determine whether to maintain / store the CPAC configuration.

[0203] a. MN and SN interaction in the case of PCell change without SN participation

[0204] At least one of the following alternatives may be used to perform the interaction between the MN and the SN. The embodiments discussed herein are non-limiting examples describing the alternatives.

[0205] • Alternative 1: The MN may inform / instruct the SN of the PCell change without the SN's involvement.

[0206] Step 1: The MN may send / transmit an indication to the SN. The indication may inform the SN of the PCell change without the SN's involvement. In some embodiments, the MN may send the indication via an X2 or Xn interface message (or other message).

[0207] Step 2: The SN may determine that the CPAC configuration should be released. If the SN determines that the CPAC configuration should be retained, the SN may inform / instruct the wireless communication device to retain / store the CPAC configuration. The SN may inform the wireless communication device by generating an RRCReconfiguration message (or other message) including an indicator.

[0208] ● Alternative 2: The MN may inform / instruct the SN of the PCell change without the SN's involvement. The MN may inform / instruct / request the SN to release the CPAC configuration.

[0209] o Step 1: MN may send a request to release the pre-configured CPAC configuration to SN using an indication. The indication may inform SN of the PCell change without SN participation via an X2 or Xn interface message (or other message).

[0210] o Step 2: The SN may determine that the request from the MN should be accepted / received. If the MN rejects the request from the MN, the SN may send / transmit a rejection message (or other message) to the MN.

[0211] Step 3: In some embodiments, the MN may receive / obtain a rejection message from the SN. If the MN receives the rejection message, the MN may send an indicator to the wireless communication device via an RRCReconfiguration message (or other message). The indicator may inform / instruct / request the wireless communication device to maintain / store the CPAC configuration.

[0212] • An indication of a PCell change without SN participation may be transmitted / sent to the SN using at least one of the following options.

[0213] Option 1: An Xn or X2 interface message (or other message) may include this indication (e.g., PCell change without SN participation). For example, an SN (SgNB) modification request message and / or other messages may include this indicator as one or more information elements.

[0214] Option 2: The Xn or X2 interface message (or other message) may include this indication as a "cause" value (or other value). For example, the "cause" value of the SN (SgNB) Modify Request message may be set / modified to indicate / specify "MN mobility without SN participation".

[0215] Option 3: The RRC message (or other message) may include / specify the indication (e.g., PCell change without SN participation). For example, the CG-ConfigInfo message may include the indication. The SN (SgNB) Modification Request message (or other message) may include the RRC message as one or more information elements.

[0216] b. Source and target interactions in the case of CPAC with MN participation

[0217] In a CPAC without MN participation, the MN can generate / configure a final RRC message (or other message) that includes the CPAC configuration. Thus, the MN can determine whether the wireless communication device stores / maintains the CPAC configuration. If the MN initiates / triggers a PCell change, the source MN can send / transmit / transmit CPAC-related information to the target MN. In response to receiving this information, the target MN can determine that the CPAC configuration stored / maintained by the wireless communication device should be released.

[0218] In some embodiments, the source MN may send / transmit a handover request message (or other message) including CPAC-related information to the target MN. The CPAC-related information may include a CPAC indicator for specifying that a CPAC has been configured, a CPAC configuration, and / or other information. The target MN may send / transmit the CPAC-related information using at least one of the following options:

[0219] Option 1: An Xn or X2 interface message (or other message) may include CPAC-related information (e.g., a CPAC indicator, a CPAC configuration encapsulated in a container, and / or other information). For example, a handover request message and / or other message may include this information as one or more information elements.

[0220] ● Option 2: The RRC message (e.g., HandoverPreparationInformation message or other message) may include / specify CPAC-related information (e.g., CPAC indicator, CPAC configuration encapsulated in a container, and / or other information). The handover request message (or other message) may include the RRC message as one or more information elements.

[0221] In some embodiments, the target MN may determine that the CPAC configuration should be released. If the MN determines that the CPAC configuration should be retained / stored, the MN may inform / instruct the wireless communication device to retain the CPAC configuration. The MN may use an indicator in an RRCReconfiguration message (or other message) to inform the wireless communication device.

[0222] In some embodiments, the target MN may transmit / transmit / send the received CPAC information to the target SN. The MN may transmit the CPAC information to the target SN using at least one of the following options.

[0223] Option 1: An Xn or X2 interface message (or other message) may include CPAC-related information (e.g., a CPAC indicator, a CPAC configuration encapsulated in a container, and / or other information). For example, an SN (SgNB) Add Request message and / or other messages may include this information as one or more information elements.

[0224] ● Option 2: The RRC message (e.g., CG-ConfigInfo message or other message) may include / specify CPAC-related information (e.g., CPAC indicator, CPAC configuration encapsulated in a container, and / or other information). The SN (SgNB) Add Request message (or other message) may include the RRC message as one or more information elements.

[0225] F. Overall Process of CPAC

[0226] a. Example 1: MN-initiated conditional SN change (MN-initiated cross-SN CPC)

[0227] Now refer to Figure 10 , depicts a communication diagram of an embodiment of a process 1000 for a conditional SN change initiated by a MN 1004. During an SN change initiated by the MN 1004, a target SN 1008 may select / identify / determine a target PSCell. The target SN 1008 may utilize measurement results associated with the target SN 1008 to select a candidate PSCell. The MN 1004 may provide / specify the measurement results to the target SN 1008. During an MN-initiated SN change, the target SN 1008 may generate / configure a configuration of candidate PSCells. During an MN-initiated SN change, one or more target SNs may be considered.

[0228] Under process 1000, the MN 1004 may initiate / trigger an SN change (210) by sending a request to the target SN 1008. The request may include a request to allocate one or more resources to the wireless communication device 1002 using an SN add procedure. The MN 1004 may send / transmit an SN add request message (or other message) to the target SN 1008. The message may include measurement results related to the target SN 1008, an indication (e.g., a CPAC indication and / or an indication specifying that the procedure corresponds to a condition-based procedure), and / or other information. In some embodiments, the MN 1004 may include in the message an indication specifying a maximum number of candidate PSCells to be configured by the target SN 1008.

[0229] In some embodiments, the target SN 1008 may receive / obtain an SN add request and / or select a candidate PSCell and SCell. The target SN 1008 may select / identify a PSCell and / or SCell by using measurement results related to the target SN 1008. The target SN 1008 may allocate one or more resources to the wireless communication device 1002. The target SN 1008 may generate / determine the configuration of the target PSCell and / or SCell. The target SN 1008 may send / transmit an SN add request confirmation (or other message) to the MN 1004 (220). The SN add request confirmation may include identification information of the target PSCell (e.g., PSCell frequency, PSCell frequency and PCI, CGI, and / or other information).

[0230] In some embodiments, the MN 1004 may send / transmit a message (e.g., an Xn-U address indication message or other message) to the source SN 1006 (230). If data forwarding is used, the message may provide / specify one or more data forwarding addresses. In response to receiving the message, the source SN 1006 may perform early data forwarding for the bearer terminated at the SN. If applicable, the source SN 1004 may send / transmit an early state transfer message (or other message) to the source MN. The message transmitted by the MN 1004 (e.g., to the source SN 1006) may include an indicator for specifying whether the process is a CPAC-based process. For example, the message may include a CPAC indicator. The MN 1004 may determine the execution condition(s) of the candidate PSCell specified in operation 220 (240).

[0231] In some embodiments, the MN 1004 may send an RRCReconfiguration message (or other message) including the CPAC configuration to the wireless communication device 1002 (250). The CPAC configuration may include at least the configuration of the candidate PSCell (e.g., the RRCReconfiguration message generated by the target SN 1008) and / or corresponding execution condition(s). The wireless communication device 1002 may send an RRCReconfigurationComplete message (or other message) to the MN 1004 to acknowledge receipt of the RRCReconfiguration message (260).

[0232] In some embodiments, the wireless communication device 1002 may maintain communication with the source SN 1006 and / or evaluate execution conditions (270). If at least one execution condition is met / satisfied, the wireless communication device 1002 may select / identify / determine the associated cell as the target PSCell. The wireless communication device may trigger / initiate execution of CPAC to access the target SN 1008.

[0233] During the execution of CPAC, the wireless communication device 1002 may send / transmit an RRCReconfigurationComplete message (or other message) to the MN 1004 (280). The message may include an embedded RRCReconfigurationComplete and / or other information to the target SN 1008. The message may indicate / include selected candidate PSCell information (e.g., target PSCell frequency and PCI, candidate cell ID and / or candidate conditional reconfiguration index), and / or other information. In response to receiving the RRCReconfigurationComplete message from the wireless communication device 1002, the MN 1002 may start forwarding data to the target SN 1008, notify the source SN 1006 to release the wireless communication device 1002 connection, and / or notify another candidate SN to release the PSCell resources reserved for CPAC.

[0234] In some embodiments, the MN 1004 may send / transmit an SN reconfiguration complete message (or other message) (290) to the target SN 1008. The MN 1004 may send the message based on the designated candidate PSCell information. The wireless communication device 1002 may perform a random access procedure (2100) toward the target PSCell of the SN 1008. The wireless communication device 1002 may send the RRCReconfigurationComplete message and / or perform the random access procedure in any order (e.g., the order of operations 280, 290, and 2100 is arbitrary).

[0235] If the random access procedure is completed, the target SN 1008 may send a message (e.g., a CPAC success message or other message) to the MN 1004 (2110). The message may inform the MN 1004 of the completion of the CPAC procedure. The message may include identification information of the target PSCell (e.g., PSCell frequency, PSCell frequency and PCI, and / or CGI), and / or other information. In response to receiving the success message, the MN 1004 may begin forwarding data toward the target SN 1008, notify / instruct the source SN 1006 to release the wireless communication device 1002 connection, and / or notify / instruct another candidate SN to release the PSCell resources reserved for CPAC.

[0236] In some embodiments, the MN 1004 may initiate / trigger the release of resources by the source SN 1006 (2120). For example, the MN 1004 may send an SN release request (or other message) to the source SN 1006 to initiate the release of resources. The source SN 1006 may confirm the release of the SN resources by sending an SN release request confirmation message (or other message) to the MN 1004 (2130). The MN 1004 may send an Xn or X2 interface message (e.g., a CPAC cancellation message or other message) to another candidate SN 1010 (2140). This message may inform / instruct / notify the other candidate SN 1010 to release the reserved candidate PSCell resources. The order of operations 2120, 2130, and 2140 is arbitrary.

[0237] b. Example 2: Conditional SN Addition (Conditional PSCell Addition Initiated by MN)

[0238] Now refer to Figure 11 , depicts a communication diagram of an embodiment of a process 1100 for conditional SN addition. In some embodiments, one or more target SNs may be considered / evaluated during the process. The steps / operations of process 1100 (e.g., steps 310 to 3110) may each include a combination of Figure 10 One or more characteristics of a description.

[0239] c. Example 3 (Solution 1): SN-initiated conditional SN change (SN-initiated cross-SN CPC)

[0240] Now refer to Figure 12, depicts a communication diagram of an embodiment of a process 1200 for a conditional SN change initiated by an SN. During an SN-initiated SN change, a target SN may select / identify / determine a target PSCell. The target SN may determine candidate PSCells by using / analyzing measurement results related to the target SN. The source SN may provide the measurement results to the target SN. In some embodiments, the target SN may generate a configuration for the candidate PSCells. One or more target SNs may be considered / evaluated during process 1200.

[0241] Under process 1200, the source SN 1206 may initiate a conditional SN change procedure (410) by sending / transmitting an SN change request message (or other message) to the MN 1204. The message may include a candidate target SN ID, the SCG configuration of the source SN 1206, measurement results related to / associated with the target SN, and / or other information. The message may include (multiple) execution conditions for the candidate PSCells, an indication that the procedure is a conditional procedure (e.g., a CPAC indication or other indication), and / or other information. In the message, the source SN 1206 may include an indication specifying the maximum number of candidate PSCells that can be configured by the target SN.

[0242] In some embodiments, the MN 1204 may send a request to a candidate target SN 1208 to allocate one or more resources for the wireless communication device 1202 (420). The candidate target SN 1208 may allocate the resources by using an SN add procedure. In some embodiments, the target SN 1208 may receive / obtain the SN add request and / or select candidate PSCells and SCells. The target SN 1208 may select / identify the PSCell and / or SCell by using measurement results related to the target SN 1208. The target SN 1208 may allocate one or more resources for the wireless communication device 1202. The target SN 1208 may generate / determine the configuration of the target PSCell and / or SCell. The target SN 1208 may send / transmit an SN add request confirmation (or other message) to the MN 1204 (430). The SN add request confirmation may include identification information of the target PSCell (e.g., PSCell frequency, PSCell frequency and PCI, CGI, and / or other information).

[0243] MN 1204 may send / transmit an SN change confirmation message (or other message) to source SN 1206 (440). The message may confirm the change of source SN 1206. If data forwarding is required, MN 1204 may provide one or more data forwarding addresses to source SN 1206. In some embodiments, the message may include identification information of the candidate PSCell selected by target SN 1208 (e.g., PSCell frequency, PSCell frequency and PCI, and / or CGI), an indicator indicating to source SN 1206 that the process is a conditional process (e.g., the indicator may include a "CPAC indicator"), and / or other information. If source SN 1206 receives / obtains a message with a CPAC indication, source SN 1206 may continue to provide user data (or other information) to wireless communication device 1202.

[0244] In some embodiments, the source SN 1206 may not be able to provide the execution condition(s) of the candidate PSCell in the SN change request message. Therefore, the source SN 1206 may initiate an SN-initiated SN modification process (450 / 460). The source SN 1206 may initiate / trigger / cause the process by sending an SN modification request message (or other message) to the MN 1204. The message may provide / indicate / specify the execution condition(s). The message may include the execution condition(s) related / associated with the candidate PSCell (e.g., a list of execution conditions for each frequency and / or each frequency and PCI), and / or other information. In response to receiving the message, the MN 1204 may send / transmit an SN modification confirmation message (or other message) to the source SN 1206. Each of operations 470 to 4160 may include Figure 10 The characteristic or characteristics that are relevant.

[0245] In some embodiments, the wireless communication device 1202 may send / transmit an RRCReconfigurationComplete message (or other message) to the target SN via SRB3 (eg, combining 4100 and 4110 into a single step).

[0246] d. Example 4 (Solution 2): SN-initiated conditional SN change (SN-initiated cross-SN CPC)

[0247] Now refer to Figure 13 , depicts a communication diagram of an embodiment of a process 1300 for conditional SN change initiated by an SN. One or more operations / steps of process 1300 (e.g., operations 510 to 530, 550 to 580, and 5100 to 5170) may each include Figure 12 The characteristic or characteristics that are relevant.

[0248] If data forwarding is required, the MN 1304 may send / transmit a message (e.g., an Xn-U Address Indication message) to provide one or more data forwarding addresses to the source SN 1306 (540). In response to receiving the message, the source SN 1306 may perform early data forwarding for the bearer terminated at the SN. The source SN 1306 may send / transmit an Early State Transfer message (or other message) to the source MN 1304. The message may include an indicator specifying that the process is a conditional process (e.g., the message may include a "CPAC indicator"), identification information of the candidate PSCell selected by the target SN (e.g., PSCell frequency, PSCell frequency and PCI, and / or CGI), and / or other information.

[0249] In some embodiments, the MN 1304 may send / transmit an SN change confirmation message (or other message) (590) to the source SN 1306. The message may provide / indicate / specify confirmation of the change of the source SN 1306. The message may include an indicator indicating that the process is a conditional process (e.g., the message may include a "CPAC indicator"), and / or other information. If the source SN 1306 receives the message with the CPAC indication, the source SN 1306 may continue to provide user data (or other information) to the wireless communication device 1302.

[0250] e. Example 5 (Solution 3): SN-initiated conditional SN change (SN-initiated cross-SN CPC)

[0251] Now refer to Figure 14 , depicts a communication diagram of an embodiment of a process 1400 for conditional SN change initiated by an SN. One or more operations / steps of process 1400 (e.g., operations 610 to 6130 and 6150) may each include Figure 13 The characteristic or characteristics that are relevant.

[0252] In some embodiments, in response to receiving a message (e.g., a CPAC success message or other message) from the target SN, the MN 1404 may send / transmit an SN change confirmation message (or other message) (6140) to the source SN 1406. The message may provide confirmation of releasing resources of the source SN 1406. In response to receiving the message, the source SN 1406 may be caused to stop providing user data (or other information) to the wireless communication device 1402. In some embodiments, the source SN 1406 may start / initiate data forwarding.

[0253] f. Example 6: Conditional SN modification initiated by SN with MN participation (CPC within SN initiated by MN participation)

[0254] Now refer to Figure 15 , depicts a communication diagram of an embodiment of a process 1500 for conditional SN modification initiated by an SN with MN participation. During SN modification initiated by a source SN without MN participation, the source SN 1506 may select / identify / determine a candidate PSCell. The source SN 1506 may generate / configure the configuration of the candidate PSCell and / or corresponding execution conditions. One or more operations / steps of process 1500 (e.g., operations 720 to 730 and 750 to 760) may each include the following: Figure 14 The characteristic or characteristics that are relevant.

[0255] In some embodiments, the source SN 1506 may send / transmit an SN modification request message (or other message) (710) to the MN 1504. The message may cause the initiation of CPC within the SN with the MN participating. The message may include one or more candidate PSCell configurations, execution conditions (multiple) of the candidate PSCells, an indication that the procedure is a conditional procedure (e.g., a CPAC indication), and / or other information.

[0256] In response to receiving the SN modification request message, MN 1504 may send / transmit an SN modification confirmation message (or other message) to source SN 1506 (740). In some embodiments, the transmission of the SN modification confirmation message may be excluded from operation 740 of the process. MN 1504 may send a confirmation message (e.g., in operation 770) in response to receiving / obtaining the second RRCReconfigurationComplete message from wireless communication device 1502. In some embodiments, MN 1504 may transmit / send / transmit an SN reconfiguration completion message (or other message) to source SN 1506 (770). The message may indicate / signal the success of the CPAC process. In some embodiments, MN 1504 may send an SN modification confirmation message including the SN RRCReconfigurationComplete message to source SN 1506.

[0257] In some embodiments, the wireless communication device 1502 may perform synchronization toward the PSCell configured by the SN (780). In some embodiments, the wireless communication device 1502 may perform uplink transmissions after applying the new configuration. The MN 1504 may send / transmit an Xn or X2 interface message (e.g., a CPAC cancellation message or other message) to the other potential SN(s) 1508 (790). The message may inform the other potential SN(s) 1508 to release the reserved candidate PSCell resources.

[0258] G. Methods for Improving Mobility Reliability During PSCell Addition or Change

[0259] Figure 16 A flow chart of a method 1600 for improving mobility reliability in PSCell addition or change is shown. The method 1600 may be used in conjunction with the Figures 1-15 In general, the method 1600 may include sending a maximum number of PSCells (1652). The method 1600 may include receiving a message with at least one PSCell configuration (1654). The method 1600 may include determining whether data forwarding is required (1656). The method 1600 may include sending a data forwarding message (1658). The method 1600 may include omitting the data forwarding message (1660). The method 1600 may include sending an RRC message (1662).

[0260] Now referring to operation (1652), and in some embodiments, a master node (MN) may send and / or transmit an indication of the maximum number of primary cells (PSCells) in a candidate secondary cell group. Before sending the indication, the MN may determine the maximum number of candidate PSCells that can be configured by the target secondary node (SN). The target SN may receive / obtain the indication from the MN. The maximum number of candidate PSCells may be configured by the target SN. The MN may send / transmit the indication in an SN add request message (or other message). In some embodiments, the SN add request message may include / provide / specify the indication of the maximum number of candidate PSCells in an information element.

[0261] Referring now to operation (1654), in some embodiments, the MN may receive a message with at least one candidate PSCell configuration. The target SN may send / transmit the message to the MN. The message may include an SN Add Request Confirmation message (or other message). The MN may receive / obtain the message from the target SN in response to sending / transmitting the SN Add Request message (or other message).

[0262] Referring now to operation (1656), in some embodiments, the MN may determine whether data forwarding is required. If data forwarding is required, the MN may send / transmit a data forwarding message with an indication to the source SN (1658). The MN may send the data forwarding message in response to determining that data forwarding is required. The data forwarding message may include an indication that the data forwarding is for a procedure based on conditional PSCell addition or change (CPAC). The MN may send / transmit / transmit the indication using an Xn interface or X2 interface message (e.g., as in an information element or "cause" value) and / or other messages. In response to receiving the message, the source SN may decide that early data forwarding should be performed for the bearer terminated at the SN. If the MN determines that data forwarding is unnecessary / unnecessary, the MN may omit / skip the data forwarding message (1660). The data forwarding message (e.g., an RRC message or other message) may include / provide / specify in an information element an indication that the data forwarding is for a CPAC procedure.

[0263] Now referring to operation (1662), and in some embodiments, the MN may send / transmit an RRC message. The MN may send an RRC message to the wireless communication device, the RRC message including at least one candidate PSCell configuration and / or one or more associated CPAC execution conditions. In response to sending the RRC message, the MN may cause the wireless communication device to perform a CPAC process on the target SN. The candidate PSCell may meet / satisfy at least one CPAC execution condition of the one or more CPAC execution conditions. If the candidate PSCell satisfies at least one condition, the wireless communication device may perform the CPAC process on the target SN. The wireless communication device may select / identify a candidate PSCell residing in a candidate SN other than the source SN. When single radio bearer three (SRB3) is not configured, the wireless communication device may select a candidate PSCell residing in the source SN. The wireless communication device may select a candidate PSCell to perform / execute the CPAC process on the selected candidate PSCell.

[0264] In some embodiments, the MN may receive / obtain an RRC message (or other message) from a wireless communication device. This message may indicate the execution of the CPAC procedure for the selected candidate PSCell. In response to receiving the RRC message, the MN may send / transmit / communicate an Xn interface or X2 interface message (or other message) to one or more candidate SNs other than the target SN. The Xn interface or X2 interface message may cause the release of resources reserved for the CPAC procedure. In some embodiments, the MN may receive / obtain an Xn interface or X2 interface message (or other message) from the target SN. This message may indicate the successful completion of the CPAC procedure. This message may include identification information and / or other information of the selected PSCell. The MN may send / transmit / broadcast another Xn interface or X2 interface message to one or more candidate SNs other than the target SN. This message may cause / trigger the release of resources reserved for the CPAC procedure. In some embodiments, the MN may send an SN release message (or other message) to the source SN. The MN may send this message when the selected PSCell is not a candidate PSCell residing in the source SN. This message may indicate the release of resources of the source SN. This message may cause / trigger the source SN to stop providing user data (or other information) to the wireless communication device.

[0265] In some embodiments, the MN may determine whether the CPAC configuration of one or more candidate PSCells should be modified and / or canceled. The MN may utilize / analyze measurement results associated with the target SN to determine whether the configuration(s) should be modified and / or canceled. The MN may send / transmit a message to the target SN. The message may indicate the modification and / or cancellation of the CPAC configuration of one or more candidate PSCells. The message may include / provide identification information (e.g., frequency, frequency and PCI, CGI, and / or other information) regarding the one or more candidate PSCells to be modified and / or canceled. In some embodiments, the target SN may receive / obtain measurement results associated with the target SN from the MN. The target SN may determine whether the CPAC configuration of one or more candidate PSCells should be modified and / or canceled based on the measurement results (or other information). The target SN may send / transmit a message to the MN. The message may indicate the modification or cancellation of the CPAC configuration of one or more candidate PSCells. The message may include / provide identification information (e.g., frequency, frequency and PCI, CGI, and / or other information) regarding the one or more candidate PSCells to be modified and / or canceled.

[0266] In some embodiments, the MN may send / transmit / broadcast an Xn interface or X2 interface message (or other message) to the target SN. The message may include / provide a request to release the CPAC configuration of the configured candidate PSCell. The Xn interface or X2 interface message may include at least one of the following: identification information about the configured candidate PSCell (e.g., frequency, frequency and PCI, CGI, and / or other information), and / or an indication about releasing the CPAC configuration related to replacing the CPAC configuration with a new CPAC configuration. In some embodiments, the target SN may send / transmit an Xn interface or X2 interface message (or other message) to the MN. The message may include / provide a request to release the CPAC configuration of the configured candidate PSCell. The message may include at least one of the following: identification information about the configured candidate PSCell, and / or an indication about releasing the CPAC configuration related to replacing the CPAC configuration with a new CPAC configuration.

[0267] In some embodiments, the target SN may receive / obtain an Xn interface or X2 interface message (or other message) from the MN. The message may include a request to add a new CPAC configuration. The message may include at least one of the following: identification information of the PSCell to be modified (e.g., frequency, frequency and PCI, CGI, and / or other information), an updated source secondary cell group (SCG) configuration, measurement results related to the target SN, and / or instructions for adding and replacing the CPAC configuration with a new CPAC configuration. The Xn interface or X2 interface request / message may include an indication of releasing and replacing the CPAC configuration with a new CPAC configuration. The Xn interface or X2 interface request / message may include the indication of the release in one or more information elements and / or cause values. The Xn interface or X2 interface request / message may include an indication of adding and replacing the CPAC configuration with a new CPAC configuration. The Xn interface or X2 interface request / message may include the indication of the addition in one or more information elements and / or cause values.

[0268] In some embodiments, the MN may send / transmit / broadcast an Xn interface or X2 interface message (or other message) to the source SN. The message may include an indication of the maximum number of cells allowed to be configured as candidate cells for the CPAC process. The RRC message (or other message) may include an indication of the maximum number of cells. The Xn interface or X2 interface message (or other message) may include / provide an RRC message. In some embodiments, the MN may receive / obtain a request from the source SN via an Xn interface or X2 interface message (or other message). If the source SN determines that more candidate cells are needed, the source SN may send the request. The request may include a request for a reference number of cells (e.g., the total number of cells and / or an increased number) allowed to be configured as candidate cells for the CPAC process. The RRC message may include / provide / specify the reference number of cells. The Xn interface or X2 interface message may include / provide an RRC message. In some embodiments, the MN may determine whether the reference number of cells in the request should be accepted or rejected.

[0269] Figure 17 A flow chart of a method 1700 for improving mobility reliability in PSCell addition or change is shown. The method 1700 may be used in conjunction with the Figures 1-15 In general, method 1700 may include receiving an SN change request message (1752). Method 1700 may include sending a maximum number of candidate PSCells (1754). Method 1700 may include receiving at least one configuration (1756). Method 1700 may include sending an RRC message (1758).

[0270] Now referring to operation (1752), in some embodiments, the MN may receive an SN change request message. The source SN may send / transmit the SN change request message (or other message) to the MN. The MN may receive / obtain the SN change request message (or other message) from the source SN. The SN change request message may include / provide an indication of the maximum number of candidate PSCells that can be configured by the target SN and / or other information. In some embodiments, the MN may receive / obtain an Xn interface or X2 interface message (or other message) from the source SN (e.g., an SN-initiated CPAC). The Xn interface or X2 interface message may provide a request to release the CPAC configuration of the configured candidate PSCells. The Xn interface or X2 interface message may include identification information (e.g., frequency, frequency and PCI, CGI, and / or other information) of one or more candidate PSCells to be released or modified, an indication regarding the release and replacement of the CPAC configuration with a new CPAC configuration, and / or other information. The MN may send / transmit another Xn interface or X2 interface message (or other message) to the target SN. The other Xn interface or X2 interface message may provide a request to release the CPAC configuration of the configured candidate PSCells. Another Xn interface message or X2 interface message may include identification information (e.g., frequency, frequency and PCI, CGI, and / or other information) of one or more candidate PSCells to be released or modified, an indication of the release associated with replacing the CPAC configuration with a new CPAC configuration, and / or other information. In some embodiments, one or more information elements and / or cause values ​​of the Xn interface or X2 interface message may include / provide an indication of the release associated with replacing the CPAC configuration with a new CPAC configuration.

[0271] Now referring to operation (1754), and in some embodiments, the MN may send a maximum number of candidate PSCells. The MN may send / transmit / broadcast an indication of the maximum number of candidate PSCells to the target SN. The maximum number of candidate PSCells may be configured by the target SN. The SN add request message (or other message) may include / provide / specify the indication. In some embodiments, one or more information elements of the message (e.g., the SN add request message or other message) may include / provide / specify an indication of the maximum number of candidate PSCells and / or other information. In some embodiments, the MN may send / transmit an indication to the source SN. The indication may specify the maximum number of cells allowed to be configured as candidate cells for the CPAC process. The MN may send the indication via another Xn interface or X2 interface message (or other message). The RRC message (or other message) may include / provide an indication of the maximum number of cells. The another Xn interface or X2 interface message may include / provide / specify the RRC message.

[0272] Referring now to operation (1756), in some embodiments, the MN may receive a message with at least one PSCell configuration. The MN may receive at least one candidate PSCell configuration from the target SN in response to the SN Add Request message. The SN Add Request Confirmation message (or other message) may include / provide / indicate / specify at least one candidate PSCell configuration. In some embodiments, the source SN may send / transmit measurement results (or other information) related to / associated with the target SN (e.g., SN-initiated CPAC) to the target SN. The target SN may utilize the measurement results to determine whether the CPAC configuration of one or more candidate PSCells should be modified and / or canceled.

[0273] In some embodiments, the MN may receive / obtain an Xn interface or X2 interface message (or other message) from a target SN (e.g., a CPAC modification initiated by the target SN). The message may provide a request to release the CPAC configuration of a configured candidate PSCell. The Xn interface or X2 interface message may include identification information of one or more candidate PSCells to be released or modified, an indication regarding the release associated with replacing the CPAC configuration with a new CPAC configuration, and / or other information. In some embodiments, one or more information elements and / or cause values ​​of the Xn interface or X2 interface message may include / provide an indication regarding the release associated with replacing the CPAC configuration with a new CPAC configuration. In some embodiments, the MN may send / transmit an Xn interface or X2 interface message (or other message) to the target SN (e.g., a CPAC initiated by the SN). The Xn interface or X2 interface message may provide a request to add a new CPAC configuration. The Xn interface or X2 interface message may include / provide identification information (e.g., frequency, frequency and PCI, CGI, and / or other information) of one or more candidate PSCells to be added or modified, an updated SCG configuration, measurement results related to the target SN, an indication related to adding or replacing a CPAC configuration with a new CPAC configuration, and / or other information. In some embodiments, one or more information elements and / or cause values ​​of the Xn interface or X2 interface message may include / provide an indication related to adding or replacing a CPAC configuration with a new CPAC configuration.

[0274] In some embodiments, the MN may send an indication of a change association. The MN may send / transmit / broadcast an indication to the source SN. The source SN may receive / obtain the indication from the MN. The indication may specify that the change from the source SN to the target SN is associated with a CPAC-based process. In some embodiments, an Xn interface or X2 interface message (or other message) may provide / specify the indication. The MN may send the indication to the source SN using an SN change confirmation message (or other message) to inform the source SN of the CPAC-based process. In some embodiments, the source SN may determine whether the CPAC configuration of one or more candidate PSCells should be modified and / or canceled. The source SN may utilize / analyze measurement results related to the target SN to determine whether the CPAC configuration should be modified and / or canceled. The source SN may inform the target SN of the identification information of one or more candidate PSCells to be modified and / or canceled.

[0275] One or more information elements of an Xn or X2 interface message (or other message) may include / provide / specify an indication regarding a change associated with a CPAC-based procedure. In some embodiments, an Xn or X2 interface message (or other message) may include / provide / specify identification information (e.g., frequency, frequency and PCI, CGI, and / or other information) of one or more PSCells already configured by the target SN. The message may include / initiate a procedure for notifying the source SN of the identification information in the case of an SN-initiated conditional SN change. In some embodiments, an Xn or X2 interface message (or other message) may be an address indication message. The message may provide / specify / instruct data forwarding information (or other information) to the source SN. In some embodiments, the Xn or X2 interface message is an SN change confirmation message (or other message). The SN change confirmation message may confirm / verify / authenticate the release of resources of the source SN. The SN change confirmation message may instruct the source SN to continue providing user data (or other information) to the associated wireless communication device.

[0276] Now referring to operation (1758), and in some embodiments, the MN may send an RRC message. The MN may send / transmit an RRC message (or other message) to the wireless communication device. The RRC message may include at least one candidate PSCell configuration, one or more associated CPAC execution conditions and / or other information. In response to receiving the message, when the candidate PSCell satisfies at least one of the one or more CPAC execution conditions, the wireless communication device may perform a CPAC process on the target SN. In some embodiments, the wireless communication device may select / identify / determine a candidate PSCell residing in a candidate SN other than the source SN. When single radio bearer three (SRB3) is not configured, the wireless communication device may select a candidate PSCell residing in the source SN. The wireless communication device may select a candidate PSCell to perform a CPAC process on the selected candidate PSCell.

[0277] In response to selecting a candidate PSCell, the wireless communication device may send / transmit an RRC message (or other message) to the MN. The RRC message may indicate / specify the execution of the CPAC procedure for the selected candidate PSCell. In response to the RRC message, the MN may send / transmit an Xn interface or X2 interface message (or other message) to one or more candidate SNs other than the target SN. The MN may cause / trigger the release of resources reserved for the CPAC procedure by sending this message. In some embodiments, once the wireless communication device selects a candidate PSCell, the MN may receive / obtain an Xn interface or X2 interface message (or other message) from the target SN. The Xn interface or X2 interface message may indicate / specify the successful completion of the CPAC procedure. In some embodiments, the Xn interface or X2 interface message may include / provide identification information (e.g., frequency, frequency and PCI, CGI, and / or other information) of the selected candidate PSCell. The MN may send / transmit another Xn interface or X2 interface message (or other message) to one or more candidate SNs other than the target SN. The MN may cause / trigger the release of resources reserved for the CPAC procedure by sending the Xn interface or X2 interface message.

[0278] In some embodiments, the source SN may receive / obtain another Xn interface or X2 interface message (or other message) from the MN. The MN may send / transmit this message when the selected candidate PSCell is not a candidate PSCell residing in the source SN. The MN may send this message to indicate / specify / instruct the release of resources of the source SN. In response to receiving this message, the source SN may stop providing user data (or other information) to the wireless communication device. In some embodiments, the other Xn interface or X2 interface message may include an SN release message, an SN change confirmation message, and / or other messages.

[0279] In some embodiments, the source SN may send / transmit a request to the MN. The request may include a request for a reference number of cells (e.g., a total number of cells or an increased number of cells) that are allowed to be configured as candidate cells for the CPAC process. If the SN needs / wants more candidate cells, the SN may send the request. The SN may send the request before initiating / triggering a MN-initiated or SN-initiated CPAC process. In some embodiments, an RRC message (or other message) may include the reference number of cells. Another Xn interface or X2 interface message may include / provide the RRC message. In some embodiments, the MN may determine whether the reference number of cells in the request should be accepted or rejected.

[0280] Although various embodiments of the present solution have been described above, it should be understood that they are presented as examples only and not as limitations. Similarly, various figures may depict example architectures or configurations, which are provided to enable those of ordinary skill in the art to understand the example features and functions of the present solution. However, such persons will understand that the solution is not limited to the example architectures or configurations shown, but can be implemented using various alternative architectures and configurations. In addition, as those of ordinary skill in the art will understand, one or more features of one embodiment may be combined with one or more features of another embodiment described herein. Therefore, the breadth and scope of the present disclosure should not be limited by any of the above-described illustrative embodiments.

[0281] It should also be understood that any reference to an element herein using names such as "first," "second," etc. does not generally limit the number or order of those elements. Rather, these names may be used herein as a convenient means of distinguishing between two or more elements or instances of an element. Thus, a reference to a first element and a second element does not imply that only two elements may be used, or that the first element must precede the second element in some manner.

[0282] Furthermore, persons of ordinary skill in the art will appreciate that information and signals may be represented using any of a variety of different methods and techniques. For example, data, instructions, commands, information, signals, bits, and symbols, etc., as referenced in the above description, may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0283] Those of ordinary skill in the art will further understand that any of the various illustrative logical blocks, modules, processors, components, circuits, methods, and functions described in conjunction with the aspects disclosed herein may be implemented by electronic hardware (e.g., digital implementation, analog implementation, or a combination of the two), firmware, various forms of programs or design code incorporating instructions (which, for convenience, may be referred to herein as "software" or "software modules"), or any combination of these technologies. To clearly illustrate this interchangeability of hardware, firmware, and software, various illustrative components, blocks, modules, circuits, and steps have been generally described above in terms of their functionality. Whether such functionality is implemented as hardware, firmware, software, or a combination of these technologies depends on the specific application and the design constraints imposed on the overall system. A skilled person may implement the described functionality in various ways for each specific application, but such implementation decisions do not result in a departure from the scope of this disclosure.

[0284] In addition, it will be understood by those skilled in the art that the various illustrative logic blocks, modules, devices, components, and circuits described herein may be implemented within or performed by an integrated circuit (IC), which may include a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic device, or any combination thereof. The logic blocks, modules, and circuits may also include an antenna and / or a transceiver to communicate with various components within a network or within a device. The general-purpose processor may be a microprocessor, but in an alternative, the processor may be any conventional processor, controller, or state machine. The processor may also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in combination with a DSP core, or any other suitable configuration for performing the functions described herein.

[0285] If implemented in software, these functions can be stored as one or more instructions or codes on a computer-readable medium. Therefore, the steps of the method or algorithm disclosed herein can be implemented as software stored on a computer-readable medium. Computer-readable media include both computer storage media and communication media, including any medium capable of transferring a computer program or code from one place to another. The storage medium can be any available medium that a computer can access. By way of example and not limitation, such computer-readable media can include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage device, or any other medium that can be used to store the desired program code in the form of instructions or data structures and that can be accessed by a computer.

[0286] In this document, the term "module" as used herein refers to software, firmware, hardware, and any combination of these elements for performing the relevant functions described herein. In addition, for the purpose of discussion, various modules are described as discrete modules; however, as is clear to one of ordinary skill in the art, two or more modules can be combined to form a single module that performs the associated functions according to embodiments of the present solution.

[0287] In addition, memory or other storage devices and communication components may be used in embodiments of the present solution. It should be understood that for clarity, the above description has described embodiments of the present solution with reference to different functional units and processors. However, it is clear that any suitable distribution of functionality between different functional units, processing logic elements or domains may be used without departing from the present solution. For example, functions illustrated as being performed by separate processing logic elements or controllers may be performed by the same processing logic element or controller. Therefore, references to specific functional units are merely references to appropriate means for providing the described functionality, rather than representing a strict logical or physical structure or organization.

[0288] Various modifications to the embodiments described in this disclosure will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments without departing from the scope of this disclosure. Therefore, the present disclosure is not intended to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the novel features and principles disclosed herein, as set forth in the following claims.

Claims

1. A method for conditional primary cell addition or change (CPAC) in a secondary cell group, the method comprising: In a secondary node (SN) add request message, a master node (MN) sends an indication of the maximum number of primary cells (PSCells) in a candidate secondary cell group that can be configured by the target SN to the target SN; In response to the SN add request message, the MN receives an SN add request confirm message having at least one candidate PSCell configuration from the target SN; as well as The MN sends a radio resource control (RRC) message including the at least one candidate PSCell configuration and one or more associated CPAC execution conditions to the wireless communication device, so as to cause the wireless communication device to perform a CPAC process on the target SN when the candidate PSCell satisfies the one or more associated CPAC execution conditions; as well as If data forwarding is to be performed, the MN sends a data forwarding message to the source SN, wherein the data forwarding message has an indication that the data forwarding is for the CPAC process, wherein the indication that the data forwarding is for the CPAC process is included in the information element of the data forwarding message. 2 . The method according to claim 1 , wherein the indication of the maximum number of candidate PSCells is included in an information element of the SN add request message. 3 . The method according to claim 1 , wherein the wireless communication device selects a candidate PSCell to perform a CPAC process on the selected candidate PSCell.

4. The method according to claim 3, comprising: Receiving, by the MN, an RRC message from the wireless communication device, the RRC message indicating execution of the CPAC procedure for the selected candidate PSCell; as well as The MN sends an Xn interface or X2 interface message to one or more candidate SNs other than the target SN in response to the RRC message to release resources reserved for the CPAC process.

5. The method according to claim 4, comprising: The MN sends an SN release message to the source SN to indicate the release of the resources of the source SN and cause the source SN to stop providing user data to the wireless communication device.

6. The method according to claim 1, comprising: The MN sends an indication of the maximum number of cells allowed to be configured as candidate cells for the CPAC process to the source SN via an Xn interface or an X2 interface message, wherein the CPAC process is initiated by the source SN.

7. The method according to claim 6, wherein the indication of the maximum number of cells is included in an RRC message, the RRC message is included in the Xn interface or X2 interface message, and the RRC message is a CG-ConfigInfo message.

8. A method for conditional primary cell addition or change (CPAC) in a secondary cell group, the method comprising: receiving, by a target SN from a master node (MN) in a secondary node (SN) add request message, an indication of a maximum number of primary cells (PSCells) in a candidate secondary cell group that can be configured by the target SN; as well as In response to the SN add request message, the target SN sends an SN add request confirmation message with at least one candidate PSCell configuration to the MN, The MN sends a radio resource control (RRC) message including the at least one candidate PSCell configuration and one or more associated CPAC execution conditions to the wireless communication device, so as to cause the wireless communication device to perform a CPAC process on the target SN when the candidate PSCell satisfies the one or more associated CPAC execution conditions; If data forwarding is to be performed, the MN sends a data forwarding message to the source SN, wherein the data forwarding message has an indication that the data forwarding is for the CPAC process, and wherein the indication that the data forwarding is for the CPAC process is included in the information element of the data forwarding message.

9. The method of claim 8, wherein the indication of the maximum number of candidate PSCells is included in an information element of the SN add request message. 10 . The method according to claim 8 , wherein the wireless communication device selects a candidate PSCell to perform a CPAC process on the selected candidate PSCell.

11. The method according to claim 10, wherein The MN receives an RRC message from the wireless communication device, the RRC message indicating the execution of the CPAC process on the selected candidate PSCell, and in response to the RRC message, sends an Xn interface or X2 interface message to one or more candidate SNs other than the target SN to release resources reserved for the CPAC process.

12. The method according to claim 11, wherein the MN sends an SN release message to the source SN to indicate the release of resources of the source SN and to cause the source SN to stop providing user data to the wireless communication device.

13. The method according to claim 8, wherein the MN sends an indication of the maximum number of cells allowed to be configured as candidate cells for the CPAC process to the source SN via an Xn interface or an X2 interface message, wherein the CPAC process is initiated by the source SN.

14. The method according to claim 13, wherein the indication of the maximum number of cells is included in an RRC message, the RRC message is included in the Xn interface or X2 interface message, and the RRC message is a CG-ConfigInfo message.

15. A master node (MN), comprising: at least one processor configured to: sending, in a secondary node (SN) add request message, to a target SN via a transceiver, an indication of a maximum number of primary cells (PSCells) in a candidate secondary cell group that can be configured by the target SN; receiving, in response to the SN add request message, an SN add request confirm message having at least one candidate PSCell configuration from the target SN via the transceiver; as well as sending, via the transceiver, a radio resource control (RRC) message including the at least one candidate PSCell configuration and one or more associated conditional PSCell addition and change CPAC execution conditions to a wireless communication device, to cause the wireless communication device to perform a CPAC procedure on the target SN when the candidate PSCell satisfies the one or more associated CPAC execution conditions; as well as If data forwarding is to be performed, the MN sends a data forwarding message to the source SN, wherein the data forwarding message has an indication that the data forwarding is for a process based on conditional PSCell addition or change (CPAC), wherein the indication that the data forwarding is for the CPAC process is included in the information element of the data forwarding message.

16. A target secondary node (SN), comprising: at least one processor configured to: receiving, in an SN add request message, from a master node (MN) via a transceiver, an indication of a maximum number of primary cells (PSCells) in a candidate secondary cell group that can be configured by the target SN; In response to the SN add request message, sending an SN add request confirm message having at least one candidate PSCell configuration to the MN via the transceiver, wherein the MN sends a radio resource control (RRC) message to the wireless communication device to cause the wireless communication device to perform a CPAC procedure on the target SN when a candidate PSCell satisfies one or more associated conditional PSCell addition or change (CPAC) execution conditions, the RRC message including the at least one candidate PSCell configuration and the one or more associated CPAC execution conditions; and If data forwarding is to be performed, the MN sends a data forwarding message to the source SN, wherein the data forwarding message has an indication that the data forwarding is for a CPAC process, and wherein the indication that the data forwarding is for the CPAC process is included in an information element of the data forwarding message.

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