MN-initiated inter-SN conditional PS cell change update

Abstract

The method includes transmitting a configuration to a user equipment, the configuration including a master node initiated conditional cell change, and transmitting a notification from the master node to a source secondary node in response to preparing the conditional cell change, the notification relating to the master node initiated conditional cell change, the notification including an indication of whether the source secondary node should perform an early data transfer from the source secondary node to the target secondary node.

Description

[Technical Field]

[0001] Example and non-limiting embodiments relate generally to communications, and more particularly to MN-initiated inter-SN conditional PS cell change updates. [Background technology]

[0002] It is known to facilitate communication between user equipment and base stations, for example to perform handover in a communication network or to perform dual connectivity in a communication network. Summary of the Invention

[0003] According to an aspect, a method includes transmitting a configuration to a user equipment, the configuration including a master node initiated conditional cell change; and transmitting a notification from the master node to a source secondary node in response to preparing the conditional cell change, the notification relating to the master node initiated conditional cell change, the notification including an indication of whether the source secondary node should perform an early data transfer from the source secondary node to the target secondary node.

[0004] According to an aspect, a method includes transmitting a configuration to a user equipment, the configuration including an intra-secondary node conditional cell change associated with a source secondary node; receiving an indication from the user equipment that the intra-secondary node conditional cell change has started to execute; and transmitting a notification from the source secondary node to a master node, the notification to the master node related to a secondary cell group configuration associated with the intra-secondary node conditional cell change, the notification to the master node including an indication of whether the master node should forward the secondary cell group configuration to the user equipment.

[0005] According to an aspect, a method includes receiving a master node-initiated conditional cell change configuration or receiving an intra-secondary-node conditional cell change configuration related to a source secondary node; receiving an indication of a preference to re-initialize the master node-initiated conditional cell change after a user equipment initiates an intra-secondary-node conditional cell change execution; receiving an instruction from the source secondary node to continue inter-secondary-node cell change evaluation based on the preference after the user equipment initiates an intra-secondary-node conditional cell change execution until expiration of a timer; starting a timer for the intra-secondary-node conditional cell change execution after receiving the instruction to continue; monitoring received signaling for at least one command for modification to the at least one pending conditional cell addition or change configuration; and releasing the at least one pending conditional cell addition or change configuration in response to not receiving the at least one command.

[0006] According to an aspect, an apparatus includes at least one processor and at least one memory including computer program code, wherein the at least one memory and the computer program code are configured, using the at least one processor, to cause the apparatus to at least: send a configuration to a user equipment, the configuration including a master node initiated conditional cell change; and send a notification from the master node to a source secondary node in response to preparing the conditional cell change, the notification related to the master node initiated conditional cell change, wherein the notification includes an indication of whether the source secondary node should perform an early data forwarding from the source secondary node to the target secondary node.

[0007] According to an aspect, an apparatus includes at least one processor and at least one memory including computer program code, wherein the at least one memory and the computer program code are configured, using the at least one processor, to cause the apparatus to at least: send a configuration to a user equipment, the configuration including an intra-secondary node conditional cell change associated with a source secondary node; receive an indication from the user equipment that the intra-secondary node conditional cell change has started to execute; and send a notification from the source secondary node to a master node, the notification to the master node related to a secondary cell group configuration associated with the intra-secondary node conditional cell change, wherein the notification to the master node includes an indication of whether the master node should forward the secondary cell group configuration to the user equipment.

[0008] According to an aspect, an apparatus includes at least one processor and at least one memory including computer program code, wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus to at least receive a master node-initiated conditional cell change configuration or receive an intra-secondary node conditional cell change configuration associated with a source secondary node; receive an indication of a preference to re-initialize the master node-initiated conditional cell change after a user equipment has initiated an intra-secondary node conditional cell change execution; receive instructions from the source secondary node to continue inter-secondary node cell change evaluation based on the preference after the user equipment has initiated an intra-secondary node conditional cell change execution until expiration of a timer; start a timer for intra-secondary node conditional cell change execution after receiving the instruction to continue; monitor received signaling for at least one command for modification to the at least one pending conditional cell addition or change configuration; and release the at least one pending conditional cell addition or change configuration in response to not receiving the at least one command.

[0009] According to an aspect, the apparatus includes means for transmitting a configuration to a user equipment, the configuration including a master node initiated conditional cell change, and means for transmitting a notification from the master node to a source secondary node in response to preparing the conditional cell change, the notification relating to the master node initiated conditional cell change, the notification including an indication of whether the source secondary node should perform an early data forwarding from the source secondary node to the target secondary node.

[0010] According to an aspect, the apparatus includes means for transmitting a configuration to a user equipment, the configuration including an intra-secondary node conditional cell change associated with a source secondary node; means for receiving an indication from the user equipment that the intra-secondary node conditional cell change has started to execute; and means for transmitting a notification from the source secondary node to a master node, the notification to the master node related to a secondary cell group configuration associated with the intra-secondary node conditional cell change, the notification to the master node including an indication of whether the master node should forward the secondary cell group configuration to the user equipment.

[0011] According to an aspect, the apparatus includes means for receiving a master node initiated conditional cell change configuration or receiving an intra-secondary node conditional cell change configuration associated with a source secondary node; means for receiving an indication of a preference to reinitialize the master node initiated conditional cell change after a user equipment has initiated an intra-secondary node conditional cell change execution; means for receiving an instruction from the source secondary node to continue inter-secondary node cell change evaluation based on the preference after the user equipment has initiated an intra-secondary node conditional cell change execution until expiration of a timer; means for starting a timer for intra-secondary node conditional cell change execution after receiving the instruction to continue; means for monitoring received signaling for at least one command for modification to at least one pending conditional cell addition or change configuration; and means for releasing the at least one pending conditional cell addition or change configuration in response to not receiving the at least one command.

[0012] According to an aspect, a machine-readable non-transitory program storage device is provided that tangibly embodies a program of instructions executable by a machine to perform operations, the operations including: transmitting a configuration to a user equipment, the configuration including a master node-initiated conditional cell change; and transmitting a notification from the master node to a source secondary node in response to preparing the conditional cell change, the notification related to the master node-initiated conditional cell change, the notification including an indication of whether the source secondary node should perform an early data transfer from the source secondary node to the target secondary node.

[0013] According to an aspect, a machine-readable non-transitory program storage device is provided that tangibly embodies a program of instructions executable by a machine to perform operations, the operations including: transmitting a configuration to a user equipment, the configuration including an intra-secondary node conditional cell change associated with a source secondary node; receiving an indication from the user equipment that the intra-secondary node conditional cell change has begun execution; and transmitting a notification from the source secondary node to a master node, the notification to the master node related to a secondary cell group configuration associated with the intra-secondary node conditional cell change, the notification to the master node including an indication of whether the master node should forward the secondary cell group configuration to the user equipment.

[0014] According to an aspect, a machine-readable non-transitory program storage device is provided that tangibly embodies a program of instructions executable by a machine to perform operations, the operations including receiving a master node-initiated conditional cell change configuration or receiving an intra-secondary node conditional cell change configuration associated with a source secondary node; receiving an indication of a preference to re-initialize the master node-initiated conditional cell change after a user equipment has initiated an intra-secondary node conditional cell change execution; receiving an instruction from the source secondary node to continue inter-secondary node cell change evaluation based on the preference after the user equipment has initiated an intra-secondary node conditional cell change execution until expiration of a timer; starting a timer for intra-secondary node conditional cell change execution after receiving the instruction to continue; monitoring received signaling for at least one command for modification to the at least one pending conditional cell addition or change configuration; and releasing the at least one pending conditional cell addition or change configuration in response to not receiving the at least one command.

[0015] The foregoing aspects and other features are explained in the following description taken in conjunction with the accompanying drawings. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a block diagram of one possible, non-limiting system in which exemplary embodiments may be implemented. [Figure 2] FIG. 10 is a diagram showing notification to an SN regarding an MN-activated CPC. [Figure 3] FIG. 10 is a diagram showing notification to an MN regarding an executed intra-SN CPC. [Figure 4] 1 is an exemplary apparatus configured to implement embodiments described herein. [Figure 5] 1 is an exemplary method performed in a MN to implement embodiments described herein. [Figure 6] 1 is an exemplary method implemented in an SN to implement embodiments described herein. [Figure 7] 1 is an exemplary method performed in a UE to implement embodiments described herein. DETAILED DESCRIPTION OF THE INVENTION

[0017] Referring to FIG. 1, this figure illustrates a block diagram of one possible, non-limiting example in which embodiments may be implemented. Shown is a user equipment (UE) 110, a radio access network (RAN) node 170, and a network element 190. In the example of FIG. 1, the user equipment (UE) 110 is in wireless communication with a wireless network 100. The UE is a wireless device that can access the wireless network 100. The UE 110 includes one or more processors 120, one or more memories 125, and one or more transceivers 130 interconnected through one or more buses 127. Each of the one or more transceivers 130 includes a receiver Rx 132 and a transmitter Tx 133. The one or more buses 127 may be address, data, or control buses and may include any interconnection mechanism, such as a series of wires on a motherboard or integrated circuit, optical fiber, or other optical communication equipment. The one or more transceivers 130 are connected to one or more antennas 128. The one or more memories 125 include computer program code 123. The UE 110 includes a module 140, which may include one or both of components 140-1 and / or 140-2, which may be implemented in many ways. The module 140 may be implemented in hardware as module 140-1, such as implemented as part of one or more processors 120. The module 140-1 may also be implemented as an integrated circuit or through other hardware, such as a programmable gate array. In another example, the module 140 may be implemented as module 140-2, which is implemented as computer program code 123 and executed by one or more processors 120. For example, the one or more memories 125 and the computer program code 123 may be configured to cause the user equipment 110, using the one or more processors 120, to perform one or more of the operations described herein. The UE 110 communicates with the RAN node 170 via a wireless link 111.

[0018] The RAN node 170 in this example is a base station that provides access to the wireless network 100 by wireless devices such as the UE 110. The RAN node 170 may be, for example, a base station for 5G, also known as New Radio (NR). In 5G, the RAN node 170 may be an NG-RAN node, which is defined as either a gNB or an ng-eNB. The gNB is a node that provides NR user plane and control plane protocol termination for UEs and is connected to a 5GC (e.g., network element 190) via an NG interface (e.g., connection 131). The ng-eNB is a node that provides E-UTRA user plane and control plane protocol termination for UEs and is connected to a 5GC via an NG interface (e.g., connection 131). The NG-RAN node may include multiple gNBs, which may also include a central unit (CU) (gNB-CU) 196 and a distributed unit (DU) (gNB-DU), of which DU 195 is shown. It should be noted that the DU 195 may include a radio unit (RU) or may be coupled to and control a radio unit (RU). The gNB-CU 196 is a logical node that hosts the gNB's radio resource control (RRC), SDAP, and PDCP protocols or the en-gNB's RRC and PDCP protocols, which control the operation of one or more gNB-DUs. The gNB-CU 196 terminates an F1 interface connected to the gNB-DU 195. The F1 interface is indicated as reference numeral 198, which also indicates a link between a remote element of the RAN node 170 and a centralized element of the RAN node 170, such as between the gNB-CU 196 and the gNB-DU 195. The gNB-DU 195 is a logical node that hosts the RLC, MAC, and PHY layers of the gNB or en-gNB, and its operation is controlled in part by the gNB-CU 196. One gNB-CU 196 supports one or more cells.One cell may be supported by one gNB-DU 195, or one cell may be supported / shared by multiple DUs under RAN sharing. The gNB-DU 195 terminates an F1 interface 198 connected to the gNB-CU 196. It should be noted that while the DU 195 is considered to include the transceiver 160, e.g., as part of an RU, some embodiments of this may have the transceiver 160 as part of a separate RU, e.g., under the control of and connected to the DU 195. The RAN node 170 may also be an eNB (Evolved Node B) base station for LTE (long term evolution) or any other suitable base station or node.

[0019] The RAN node 170 includes one or more processors 152, one or more memories 155, one or more network interfaces (N / WI / F) 161, and one or more transceivers 160, interconnected through one or more buses 157. Each of the one or more transceivers 160 includes a receiver Rx 162 and a transmitter Tx 163. The one or more transceivers 160 are connected to one or more antennas 158. The one or more memories 155 include computer program code 153. The CU 196 may include the processor 152, the memory 155, and the network interface 161. Note that the DU 195 may also include its own memory / memories and processors, and / or other hardware, which are not shown.

[0020] The RAN node 170 includes a module 150, which may include one or both of components 150-1 and / or 150-2, which may be implemented in many ways. The module 150 may be implemented in hardware as module 150-1, such as implemented as part of one or more processors 152. The module 150-1 may also be implemented as an integrated circuit or through other hardware, such as a programmable gate array. In another example, the module 150 may be implemented as module 150-2, which is implemented as computer program code 153 and executed by one or more processors 152. For example, the one or more memories 155 and the computer program code 153 are configured to cause the RAN node 170, using the one or more processors 152, to perform one or more of the operations described herein. It should be noted that the functionality of the module 150 may be distributed, such as distributed between the DU 195 and the CU 196, or may be implemented solely in the DU 195.

[0021] One or more network interfaces 161 communicate over a network, such as via links 176 and 131. Two or more gNBs 170 may communicate, for example, using link 176. Link 176 may be wired or wireless, or both, and may implement, for example, an Xn interface for 5G, an X2 interface for LTE, or other suitable interface for other standards.

[0022] The one or more buses 157 may be an address bus, a data bus, or a control bus, and may include any interconnection mechanism, such as a set of wires on a motherboard or integrated circuit, optical fiber or other optical communication equipment, a wireless channel, etc. For example, the one or more transceivers 160 may be implemented as a remote radio head (RRH) 195 for LTE or a distributed unit (DU) 195 for a gNB implementation for 5G, where other elements of the RAN node 170 are perhaps in a different physical location than the RRH / DU 195, and the one or more buses 157 may be implemented in part, for example, as optical fiber cables or other suitable network connections for connecting other elements of the RAN node 170 (e.g., a central unit (CU), gNB-CU 196) to the RRH / DU 195. Reference numeral 198 also indicates those suitable network links.

[0023] Note that while the description herein indicates that a "cell" performs a function, it should be clear that the equipment forming the cell may perform the function. A cell constitutes part of a base station. That is, there may be multiple cells per base station. For example, there may be three cells for a single carrier frequency and associated bandwidth, each covering one-third of a 360-degree area, such that the coverage area of ​​a single base station covers approximately an oval or circle. Furthermore, each cell may correspond to a single carrier, or a base station may use multiple carriers. If there are three 120-degree cells and two carriers per carrier, the base station has a total of six cells.

[0024] The wireless network 100 may include one or more network elements 190 that may include core network functionality, which provides connectivity to additional networks, such as telephone networks and / or data communication networks (e.g., the Internet), via one or more links 181. Such core network functionality for 5G may include a Location Management Function (LMF) and / or an Access and Mobility Management Function (AMF) and / or a User Plane Function (UPF) and / or a Session Management Function (SMF). Such core network functionality for LTE may include MME (Mobility Management Entity) / SGW (Serving Gateway) functionality. Such core network functionality may include SON (Self-Organizing / Optimizing Network) functionality. Note that these are merely example functions that may be supported by the network element 190, and that both 5G and LTE functions may be supported. The RAN node 170 is coupled to the network element 190 via link 131. Link 131 may implement, for example, an NG interface for 5G or an S1 interface for LTE, or other appropriate interfaces for other standards. Network element 190 includes one or more processors 175, one or more memories 171, and one or more network interfaces (N / WI / F) 180 interconnected through one or more buses 185. The one or more memories 171 include computer program code 173.

[0025] Wireless network 100 may implement network virtualization, which is the process of combining hardware and software network resources and network functionality into a single software-based management entity, a virtual network. Network virtualization involves platform virtualization, often combined with resource virtualization. Network virtualization is categorized as either external, combining many networks or portions of networks into virtual units, or internal, providing network-like functionality to software containers on a single system. It should be noted that the virtualized entities resulting from network virtualization are still implemented, at some level, using hardware, such as processor 152 or 175 and memory 155 and 171, and that it is such virtualized entities that produce the technical effect.

[0026] The computer-readable memories 125, 155, and 171 may be of any type suitable for the local technology environment and may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, flash memory, magnetic memory devices and systems, optical memory devices and systems, non-transitory memory, transient memory, fixed memory, and removable memory. The computer-readable memories 125, 155, and 171 may be means for performing storage functions. The processors 120, 152, and 175 may be of any type suitable for the local technology environment and may include, by way of non-limiting examples, one or more of a general-purpose computer, a special-purpose computer, a microprocessor, a digital signal processor (DSP), and a processor based on a multi-core processor architecture. The processors 120, 152, and 175 may be means for performing functions, such as controlling the UE 110, the RAN node 170, the network element 190, and other functions described herein.

[0027] In general, various embodiments of user equipment 110 may include, but are not limited to, cellular phones such as smartphones, tablets, personal digital assistants (PDAs) with wireless communication capabilities, portable computers with wireless communication capabilities, image capture devices such as digital cameras with wireless communication capabilities, gaming devices with wireless communication capabilities, music storage and playback devices with wireless communication capabilities, internet appliances that enable wireless internet access and browsing, tablets with wireless communication capabilities, head-mounted displays such as those implementing virtual / augmented / mixed reality, and portable units or terminals incorporating a combination of such functionality.

[0028] UE 110, RAN node 170, and / or network element 190 (and associated memory, computer program code, and modules) may be configured to implement (e.g., in part) the methods described herein, including MN-initiated inter-SN conditional PS cell change updates. Accordingly, computer program code 123, module 140-1, module 140-2, and other elements / features shown in FIG. 1 of UE 110 may implement user equipment-related aspects of the methods described herein. Similarly, computer program code 153, module 150-1, module 150-2, and other elements / features shown in FIG. 1 of RAN node 170 may implement gNB / TRP-related aspects of the methods described herein. Computer program code 173 and other elements / features shown in FIG. 1 of network element 190 may be configured to implement network element-related aspects of the methods described herein.

[0029] Having introduced a suitable, but non-limiting, technical context for the practice of the exemplary embodiments, the exemplary embodiments will now be described with greater particularity.

[0030] The embodiments described herein relate to cellular wireless network implementations, and in particular to multi-RAT mobility (MRM).

[0031] More specifically, the embodiments described herein relate to intra-Secondary Node (SN) conditional primary secondary cell (PS cell) change (CPC). CPC is a PS cell change performed by a UE when one or more execution conditions are met. When the UE receives a CPC configuration, it starts evaluating the execution conditions and stops evaluating the execution conditions when a PS cell change is triggered. In Release 17, it may occur that the SN and master node (MN) independently prepare a CPC for the same UE, thereby requiring further coordination between nodes to avoid conflicts and ambiguity. Described herein is a method by which an MN notifies an SN about an intended MN-activated CPC when the CPC is prepared. The notification of the actual trigger of the MN-activated CPC is separate from this, which may trigger early data transfer. Once notified, the SN provides the MN with information about the performed PS cell change (both classical and conditional) along with a new secondary cell group (SCG) configuration in the future.

[0032] Intra-SN CPC refers to a CPC performed or configured between cells of the same node, such as a secondary node, where the cells provide a cellular coverage area for user equipment that is given access to the communication network. Inter-SN CPC refers to a CPC performed or configured between two different secondary nodes, such as between a source secondary node and a target secondary node, which may be initiated at / by the master node. As in the intra-SN case, in the inter-SN case, cells of two different secondary nodes, such as a cell of a source secondary node and a cell of a target secondary node, provide a cellular coverage area for user equipment that is given access to the communication network.

[0033] If the SN configures the UE for intra-SN CPCs, the MN is unaware of the configuration. If the MN then prepares inter-SN CPCs, and the UE subsequently runs the intra-SN CPCs prepared by the SN, the MN is unaware that those CPCs have become invalid.

[0034] To solve this problem, the method described herein provides for the MN to notify the SN about the intended MN-activated CPC when the CPC is prepared. The notification of the actual triggering of the MN-activated CPC is separate from this. The solution further includes providing, after notification, by the SN to the MN, information about the performed PS cell change together with the new Secondary Cell Group (SCG) configuration.

[0035] In Release 16, 3GPP RAN2 enabled conditional reconfiguration, where the network provides up to eight RRC reconfigurations with associated conditions. The UE initiates the evaluation of the conditions, and if one of them is met, the UE performs the reconfiguration (and deletes the others). Once complete, the UE notifies the network. In Release 16, this feature was used to enable conditional HO (CHO) and, in the case of dual connectivity, intra-SN conditional PS cell change.

[0036] In Release 17, the idea to fully enable CPC is further developed. This means that apart from the existing intra-SN CPC (controlled only in the secondary node SN), inter-SN CPC should also be allowed and it can be initiated by the SN and by the MN. Nevertheless, the solution is built on the principles of CPC defined in Release 16. It is made explicit in Release 16 that when a UE performs one of the conditional reconfigurations, all other conditional reconfigurations are cancelled in the UE. In Release 16, this only concerns intra-SN CPC, but the same rule is observed for inter-SN CPC in Release 17.

[0037] As long as a CPC could be scheduled only by (and only involve) the SN, there was no need to coordinate the preparation with other nodes. However, in Release 17, scenarios where an SN and an MN independently prepare CPCs for the same UE must be considered. In particular, when one of the prepared CPCs is executed, other nodes that controlled some other prepared CPCs must be notified that those CPCs have been removed from the UE at the time of CPC execution.

[0038] If the inter-SN CPC is executed first, there is no problem because the source SN will discover it when the MN releases the source SCG operation. However, if the SN configures the UE for an intra-SN CPC, the MN is unaware of that configuration. If the MN then prepares an inter-SN CPC and then the UE executes the intra-SN CPC prepared by the SN, the MN will not notice that the CPC has become invalid (because the inter-SN CPC has been released by the UE).

[0039] The solution to the above situation described herein is that the SN notifies the MN when it receives information from the UE about a completed intra-SN CPC (this is already possible based on existing signaling that allows the SN to notify the MN about a performed intra-SN PS cell change). However, a simple notification is not enough. The SN also provides the current (post-CPC) SCG configuration so that the MN can re-provision its CPC if necessary.

[0040] However, to do so, several conditions must be met (i-iii): i) The SN should know about the MN-initiated inter-SN CPC; ii) The MN should know the current SCG configuration in the UE; and iii) The coordination must not confuse the UE.

[0041] The problem addressed by the embodiments described herein is how to ensure that the above requirements are met.

[0042] From Release 15 onwards, the SN may inform the MN about an SN-initiated PS cell change by including the newly configured PS cell in the MODIFICATION REQUIRED message. Successful handling of the message, however, requires that the MN forward the SCG reconfiguration to the UE (via SRB1) if included in the MODIFICATION REQUIRED message by the source SN. Thus, the SN may either (1) reconfigure the UE using the same message, or (2) send a message after the reconfiguration has taken place on SRB3, but it should not then include the current configuration (to avoid it being forwarded to the UE again). Also, the feature is optional and is typically only used when location tracking is required for the UE.

[0043] At the 3GPP RAN3#112 meeting, it was agreed that when an inter-SN CPC is prepared, the MN may notify the SN about it. However, this signaling (details are not defined) is meant to enable early data transfer from the SN (if the SN hosts PDCP). Therefore, the MN may not use the feature if PDCP is not hosted in the SN or if early data transfer is not required.

[0044] The overall solution defines the following elements (1-2):

[0045] 1) Even when early data transfer is not required or possible (no PDCP in the SN), a notification about an MN-initiated CPC is given to the SN when such a CPC is prepared. This means that the notification should contain a separate item of information about the triggering of the MN-initiated CPC, thereby allowing it to be sent without triggering data transfer.

[0046] 2) When informed about the MN-activated CPC, the SN may provide information about the performed PS cell change (both classical or conditional) along with the new SCG configuration, but providing information about the performed PS cell change must be done in such a way that the MN does not forward it to the UE (the UE already knows it).

[0047] Further features can be added to allow for the "survival" of measurements scheduled by the MN.

[0048] In step (1) above, the MN may indicate its preference to reinitialize the inter-SN CPAC after a possible intra-SN change.

[0049] Once the SN configures intra-SN CPC for the UE based on this preference, the SN instructs the UE to continue inter-SN CPAC evaluation after intra-SN CPC is performed until the defined timer duration. The UE receives new information via SN RRC signaling to continue inter-SN CPAC evaluation. The UE starts a timer for intra-SN cell change execution and waits for a modification to the CPAC command. If not received within the timer duration, the UE releases the pending CPAC configuration.

[0050] Implementation of the method described herein may be based on the following flags:

[0051] (Notification to SN regarding MN-initiated CPC)

[0052] The notification may use existing procedures (e.g., MODIFICATION REQUIRED message / procedure with information about the prepared inter-SN CPC, or ADDRESS INDICATION message / procedure) or may use a new procedure. However, it should always be sent and should include an additional flag indicating whether early data transfer is required or not (alternatively, the use of other IEs, e.g., the TEID address, may be defined so that it is clear whether early data transfer is required or not).

[0053] A proposal is shown in Figure 2. Figure 2 is a notification signaling diagram illustrating notification to an SN regarding an MN-activated CPC. In 201, an MN-activated CPC is configured for the UE 110. As an example, the MN 170-1 configures the UE 110 for the MN-activated CPC. In 202, the MN 170-1 notifies the SN 170-2 regarding the MN-activated CPC. For example, in 203, the MN 170-1 provides a flag to the source SN 170-2 indicating whether early data transfer is required. As shown in Figure 2, in item 203, the notification to the SN 170-2 regarding the MN-activated CPC may be a modification required message or procedure, an address indication message or procedure, or a new message or procedure. In 204, indicating case 1, if the flag is set to one (1), the source SN 170-2 performs early data transfer. In 205, indicating case 2, if the flag is set to zero (0), the source SN 170-2 does not perform early data transfer.

[0054] Additionally, another flag may indicate that the UE 110 must be instructed to keep the MN's (170-1) measurements alive when the intra-SN CPC is executed. Instead of a flag, the MN may also provide time information. If included, the SN should instruct the UE when configuring the intra-SN CPC not to delete the MN's measurements for a given duration (predefined or explicitly provided) when the intra-SN CPC is executed.

[0055] (Notification to MN regarding executed intra-SN CPC)

[0056] The notification may use the existing MODIFICATION REQUIRED procedure, but in that case the notification should include a flag indicating that the contained SCG configuration should not be forwarded to the UE. The notification to the MN may also use a new procedure defined to allow the notification to provide the current SCG configuration, but also to prevent the MN from forwarding the SCG configuration to the UE. The proposal is shown in Figure 3. Here, case 1 applies since intra-SN CPC is performed.

[0057] Thus, as shown in FIG. 3, in 301, intra-SN CPC is configured for UE 110. For example, source SN 170-2 configures the UE for intra-SN CPC. In 302, intra-SN CPC is executed by UE 110 and source SN 170-2. In 302, UE 110 may notify source SN 170-2 regarding the completion or execution of intra-SN CPC. In 303, source SN 170-2 notifies MN 170-1 regarding the latest SCG configuration. In 304, for example, to implement 303, source SN 170-2 sends a flag to MN 170-1 indicating whether the SCG configuration should be transferred to UE 110. Sending the flag in 304 can be performed using a modification required message / procedure or a new message or procedure. In 305, which indicates case 1, if the flag is set to zero (0), MN 170-1 does not transfer the SCG configuration to UE 110. In 306 , which shows case 2, if the flag is set to 1, the MN 170 - 1 transfers the SCG configuration to the UE 110 .

[0058] There are several advantages and technical effects of the embodiments described herein: By using the procedure of Figure 2, the SN is informed about the MN-initiated CPC even if an early data transfer should not be performed. By using the procedure of Figure 3, the MN is informed about the latest SCG configuration that should not be transferred to the UE (and can rather be used to reconfigure the inter-SN CPC).

[0059] Further advantages and technical effects of the embodiments described herein include that the methods help avoid conflicts between MN-initiated inter-SN CPC and SN-initiated intra-SN CPC. Thus, the embodiments described herein help improve mobility robustness in 5G networks.

[0060] The embodiments described herein may be standardized within, for example, TS 38.423 / 36.423, TS 38.300 / 36.300, or any applicable 3GPP specification.

[0061] 4 illustrates an exemplary apparatus 400 configured to implement embodiments described herein, which may be implemented in hardware. The apparatus 400 includes at least one processor 402 (FPGA and / or CPU) and at least one memory 404 including computer program code 405, where the at least one memory 404 and the computer program code 405 are configured to cause the apparatus 400, using the at least one processor 402, to implement circuits, processes, components, modules, or functions (collectively, control 406) for implementing embodiments described herein, including MN-initiated inter-SN conditional PS cell change updates. The memory 404 may be non-transitory, transient, volatile, or non-volatile memory.

[0062] The device 400 optionally includes a display and / or I / O interface 408 that can be used to display aspects or status of the methods described herein (e.g., as one of the methods is being performed or at a later time) or to receive input from a user, such as using a keypad. The device 400 includes one or more network (N / W) interfaces (I / Fs) 410. The N / W / I / Fs 410 may be wired and / or wireless and may communicate over the Internet / other networks via any communication technology. The N / W / I / Fs 410 may include one or more transmitters and one or more receivers. The N / W / I / Fs 410 may include standard, well-known components such as amplifiers, filters, frequency converters, modulators (demodulators), and encoder / decoder circuits, as well as one or more antennas.

[0063] The apparatus 400 for performing the functionality of the control 206 may be the UE 110, the RAN node 170, or the network element 190. Accordingly, the processor 402 may correspond to the processor 120, the processor 152, and / or the processor 175, respectively; the memory 404 may correspond to the memory 125, the memory 155, and / or the memory 171, respectively; the computer program code 405 may correspond to the computer program code 123, the module 140-1, the module 140-2, and / or the computer program code 153, the module 150-1, the module 150-2, and / or the computer program code 173, respectively; and the N / WI / F 410 may correspond to the N / WI / F 161 and / or the N / WI / F 180, respectively. Alternatively, the device 400 may be part of a self-organizing / optimizing network (SON) node, such as in a cloud, and thus may not correspond to any of the UE 110, RAN node 170, or network element 190. The device 400 may also be distributed throughout the network 100, including within and between the device 400 and any network elements (such as the network control element (NCE) 190 and / or RAN node 170 and / or UE 110).

[0064] 4 , interface 412 allows for data communication between various items of device 400. For example, interface 412 may be one or more buses, such as an address bus, a data bus, or a control bus, and may include any interconnection mechanism, such as a series of wires on a motherboard or integrated circuit, optical fiber, or other optical communication equipment. Computer program code 405, including control 406, may include object-oriented software configured to pass data / messages between objects in computer program code 405. Device 400 may include none of the features described, or may include other features as well.

[0065] 5 is an example method 500 for implementing example embodiments described herein. At 502, the method includes transmitting a configuration to a user equipment, the configuration including a master node-initiated conditional cell change. At 504, the method includes transmitting a notification from the master node to a source secondary node in response to preparing the conditional cell change, the notification related to the master node-initiated conditional cell change. At 506, the method includes the notification including an indication of whether the source secondary node should perform an early data transfer from the source secondary node to the target secondary node. Method 500 may be performed by the gNB 170, the MN 170-1, the device 400, or a combination thereof.

[0066] 6 is an example method 600 for implementing example embodiments described herein. At 602, the method includes transmitting a configuration to a user equipment, the configuration including an intra-secondary node conditional cell change associated with a source secondary node. At 604, the method includes receiving an indication from the user equipment that an intra-secondary node conditional cell change has begun execution. At 606, the method includes transmitting a notification from the source secondary node to a master node, the notification to the master node related to a secondary cell group configuration associated with the intra-secondary node conditional cell change. At 608, the method includes the notification to the master node including an indication of whether the master node should forward the secondary cell group configuration to the user equipment. Method 600 may be performed by the gNB 170, the SN 170-2, the apparatus 400, or a combination thereof.

[0067] FIG. 7 illustrates an example method 700 for implementing example embodiments described herein. At 702, the method includes receiving a master node-initiated conditional cell change configuration or receiving an intra-secondary node conditional cell change configuration associated with a source secondary node. At 704, the method includes receiving an indication of a preference to reinitialize the master node-initiated conditional cell change after the user equipment initiates execution of the intra-secondary node conditional cell change. At 706, the method includes receiving an instruction from the source secondary node to continue inter-secondary node cell change evaluation based on the preference after the user equipment initiates execution of the intra-secondary node conditional cell change until expiration of the timer. At 708, the method includes starting a timer for execution of the intra-secondary node conditional cell change after receiving the instruction to continue. At 710, the method includes monitoring received signaling for at least one command for modification to at least one pending conditional cell addition or change configuration. At 712, the method includes releasing at least one pending conditional cell addition or change configuration in response to not receiving the at least one command. Method 700 may be performed by UE 110, apparatus 400, or a combination thereof.

[0068] References to "computer," "processor," etc. should be understood to encompass computers having different architectures, such as single / multi-processor architectures and serial or parallel architectures, as well as special purpose circuitry, such as field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), signal processing devices, and other processing circuitry. References to computer programs, instructions, code, etc. should be understood to encompass software for programmable processors or firmware, e.g., the programmable contents of a hardware device, whether instructions for a processor, or configuration settings for a fixed function device, gate array, or programmable logic device.

[0069] The memories described herein may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, flash memory, magnetic memory devices and systems, optical memory devices and systems, non-transitory memory, transient memory, fixed memory and removable memory, etc. The memories may include databases for storing data.

[0070] The term "circuit" as used herein may refer to (a) hardware circuit implementations, such as implementations in analog and / or digital circuitry, and (b) combinations of circuitry and software (and / or firmware), such as (where applicable) (i) a combination of a processor, or (ii) a portion of a processor / software, including a digital signal processor, software, and memory, that work together to cause a device to perform various functions, and (c) a circuit, such as a microprocessor or portion of a microprocessor, that requires software or firmware for operation, even if the software or firmware is not physically present. As a further example, the term "circuit" as used herein also encompasses implementations of just a processor (or processors), or portion of a processor, and its (or their) accompanying software and / or firmware. The term "circuit" also encompasses, for example, and where applicable to the particular element, a baseband integrated circuit or an application processor integrated circuit for a mobile phone, or a similar integrated circuit in a server, cellular network device, or another network device.

[0071] An example method includes transmitting a configuration to a user equipment, the configuration including a master node initiated conditional cell change, and transmitting a notification from the master node to a source secondary node in response to preparing the conditional cell change, the notification relating to the master node initiated conditional cell change, the notification including an indication of whether the source secondary node should perform an early data transfer from the source secondary node to the target secondary node.

[0072] The method may further include the conditional cell change including a conditional primary-secondary cell change.

[0073] The method may further include a notification including an indication of whether the source secondary node should perform an early data forwarding being sent using at least one of a modification required procedure or message, an address indication procedure or message, or a new message or procedure.

[0074] The method may further include the indication of whether the source secondary node should perform early data transfer includes the presence or absence of a parameter, wherein the presence of the parameter having a first value indicates that early data transfer should be performed from the source secondary node to the target secondary node, and the absence of the parameter or the parameter having a second value indicates that early data transfer should not be performed from the source secondary node to the target secondary node.

[0075] The method may further include a notification related to the master node initiated conditional cell change being sent to the source secondary node when the source secondary node is not configured with early data forwarding.

[0076] The method may further include the source secondary node not being configured with early data forwarding due to the source secondary node not being configured with a packet data convergence protocol.

[0077] The method may further include receiving a notification related to the secondary cell group configuration from the source secondary node after the user equipment initiates execution of the intra-secondary node conditional cell change, and may further include the notification received from the source secondary node including an indication of whether the secondary cell group configuration should be transferred from the master node to the user equipment.

[0078] The method may further include the notification received from the source secondary node being received using at least one of a modification required message or procedure or a new message or procedure.

[0079] The method may further include transferring the secondary cell group configuration to the user equipment or not transferring the secondary cell group configuration to the user equipment based on the indication of whether the secondary cell group configuration should be transferred from the master node to the user equipment.

[0080] The method may further include the indication of whether the secondary cell group configuration should be transferred from the master node to the user equipment comprising the presence or absence of a parameter, the presence of the parameter having a first value indicating to the master node that the secondary cell group configuration should be transferred from the master node to the user equipment, and the absence of the parameter or the parameter having a second value indicating to the master node that the secondary cell group configuration should not be transferred from the master node to the user equipment.

[0081] The method may further include, after the user equipment initiates execution of the intra-secondary-node conditional cell change, indicating to the user equipment a preference for reinitializing the conditional cell change initiated at the master node; after the user equipment initiates execution of the intra-secondary-node conditional cell change until expiration of a timer, the source secondary node instructing the user equipment to continue inter-secondary-node cell change evaluation based on the preference; after receiving the instruction to continue, the user equipment starting a timer for execution of the intra-secondary-node conditional cell change; the user equipment monitoring received signaling for at least one command for modification to the at least one pending conditional cell addition or change configuration; and in response to not receiving the at least one command, the user equipment releasing the at least one pending conditional cell addition or change configuration.

[0082] An example method includes transmitting a configuration to a user equipment, the configuration including an intra-secondary node conditional cell change associated with a source secondary node; receiving an indication from the user equipment that the intra-secondary node conditional cell change has begun execution; and transmitting a notification from the source secondary node to a master node, the notification to the master node related to a secondary cell group configuration associated with the intra-secondary node conditional cell change, the notification to the master node including an indication of whether the master node should forward the secondary cell group configuration to the user equipment.

[0083] The method may further include the intra-secondary node conditional cell change including a conditional primary-secondary cell change.

[0084] The method may further include a notification including an indication of whether the master node should transfer the secondary cell group configuration to the user equipment being sent using at least one of a modification required procedure or message, or a new message or procedure.

[0085] The method may further include the indication of whether the master node should forward the secondary cell group configuration to the user equipment includes the presence or absence of a parameter, where the presence of the parameter having a first value indicates that the master node should forward the secondary cell group configuration to the user equipment, and where the absence of the parameter or the parameter having a second value indicates that the master node should not forward the secondary cell group configuration to the user equipment.

[0086] The method may further include receiving a notification from the master node related to a master node-initiated conditional cell change when the source secondary node is not configured for early data forwarding.

[0087] The method may further include the source secondary node not being configured with early data forwarding due to the source secondary node not being configured with a packet data convergence protocol.

[0088] The method may further include receiving a notification from the master node related to the master node-initiated conditional cell change, and the notification received from the master node may further include an indication of whether the source secondary node should perform an early data transfer from the source secondary node to the target secondary node.

[0089] The method may further include the notification received from the master node being received using at least one of a modification required procedure or message, an address indication procedure or message, or a new message or procedure.

[0090] The method may further include performing the early data transfer or not performing the early data transfer based on the indication of whether the source secondary node should perform the early data transfer.

[0091] The method may further include the indication of whether the source secondary node should perform early data transfer comprising the presence or absence of a parameter, the presence of the parameter having a first value indicating to the source secondary node to perform early data transfer, and the absence of the parameter or the parameter having a second value indicating to the source secondary node not to perform early data transfer.

[0092] The method may further include, after the user equipment initiates execution of the intra-secondary node conditional cell change, the master node indicating to the user equipment a preference for reinitializing the master node-initiated conditional cell change, and instructing the user equipment to continue inter-secondary node cell change evaluation based on the preference after the user equipment initiates execution of the intra-secondary node conditional cell change until expiration of a timer, wherein after receiving the instruction to continue, the user equipment starts a timer for execution of the intra-secondary node conditional cell change, the user equipment monitoring received signaling for at least one command for modification to the at least one pending conditional cell addition or change configuration, and in response to not receiving the at least one command, the user equipment releases the at least one pending conditional cell addition or change configuration.

[0093] An example method includes receiving a master node-initiated conditional cell change configuration or receiving an intra-secondary node conditional cell change configuration associated with a source secondary node; receiving an indication of a preference to reinitialize the master node-initiated conditional cell change after the user equipment has initiated execution of the intra-secondary node conditional cell change; receiving an instruction from the source secondary node to continue inter-secondary node cell change evaluation based on the preference after the user equipment has initiated execution of the intra-secondary node conditional cell change until expiration of a timer; starting a timer for execution of the intra-secondary node conditional cell change after receiving the instruction to continue; monitoring received signaling for at least one command for modification to the at least one pending conditional cell addition or change configuration; and releasing the at least one pending conditional cell addition or change configuration in response to not receiving the at least one command.

[0094] The method may further include the conditional cell change including a conditional primary secondary cell change, and the intra-secondary node conditional cell change including an intra-secondary node conditional primary secondary cell change.

[0095] The method may further include sending a notification from the master node to the source secondary node using at least one of a first modification required procedure or message, a first address indication procedure or message, or a first new message or procedure, including an indication of whether the master node should forward the secondary cell group configuration to the user equipment, and sending a notification from the source secondary node to the master node using at least one of a second modification required procedure or message, or a second new message or procedure, including an indication of whether the master node should forward the secondary cell group configuration to the user equipment.

[0096] The method may further include: the indication sent from the master node to the source secondary node of whether the source secondary node should perform early data forwarding from the source secondary node to the target secondary node comprises the presence or absence of a parameter, where the presence of the parameter having a first value indicates that early data forwarding should be performed from the source secondary node to the target secondary node, and the absence of the parameter or the parameter having a second value indicates that early data forwarding should not be performed from the source secondary node to the target secondary node; and the indication sent from the source secondary node to the master node of whether the master node should forward the secondary cell group configuration to the user equipment comprises the presence or absence of a parameter, where the presence of the parameter having a first value indicates that the master node should forward the secondary cell group configuration to the user equipment, and the absence of the parameter or the parameter having the second value indicates that the master node should not forward the secondary cell group configuration to the user equipment.

[0097] The method may further include a notification related to the master node-initiated conditional cell change being sent from the master node to the source secondary node when the source secondary node is not configured with early data forwarding.

[0098] The method may further include the source secondary node not being configured with early data forwarding due to the source secondary node not being configured with a packet data convergence protocol.

[0099] The method may further include: a notification being received at the master node from the source secondary node, the notification received from the source secondary node relating to a secondary cell group configuration after the user equipment has initiated execution of an intra-secondary node conditional cell change, the notification received from the source secondary node including an indication of whether the secondary cell group configuration should be transferred from the master node to the user equipment; and a notification related to the master node-initiated conditional cell change being received at the source secondary node from the master node, the notification received from the master node including an indication of whether the source secondary node should perform an early data transfer from the source secondary node to the target secondary node.

[0100] The method may further include the notification received from the source secondary node being received using at least one of a first modification required message or procedure, or a first new message or procedure, and the notification received from the master node being received using at least one of a second modification required procedure or message, an address indication procedure or message, or a second new message or procedure.

[0101] The method may further include, based on the indication of whether the secondary cell group configuration should be transferred from the master node to the user equipment, the secondary cell group configuration is transferred from the master node to the user equipment, or the secondary cell group configuration is not transferred from the master node to the user equipment, and based on the indication of whether the source secondary node should perform early data forwarding to the target secondary node, an early data forwarding is performed from the source secondary node to the target secondary node, or an early data forwarding is not performed from the source secondary node to the target secondary node.

[0102] The method may further include the indication of whether the secondary cell group configuration should be transferred from the master node to the user equipment comprising the presence or absence of a parameter, wherein the presence of the parameter having a first value indicates to the master node that the secondary cell group configuration should be transferred from the master node to the user equipment, and the absence of the parameter or the parameter having a second value indicates to the master node that the secondary cell group configuration should not be transferred from the master node to the user equipment, and the indication of whether the source secondary node should perform early data forwarding comprises the presence or absence of a parameter, wherein the presence of the parameter having the first value indicates to the source secondary node to perform early data forwarding to the target secondary node, and the absence of the parameter or the parameter having the second value indicates to the source secondary node not to perform early data forwarding to the target secondary node.

[0103] The method may further include performing a handover from the source secondary node to the target secondary node.

[0104] An exemplary apparatus includes at least one processor and at least one memory including computer program code, wherein the at least one memory and the computer program code are configured, using the at least one processor, to cause the apparatus to at least: send a configuration to a user equipment, the configuration including a master node-initiated conditional cell change; and send a notification from the master node to a source secondary node in response to preparing the conditional cell change, the notification related to the master node-initiated conditional cell change, wherein the notification includes an indication of whether the source secondary node should perform an early data transfer from the source secondary node to the target secondary node.

[0105] An example apparatus includes at least one processor and at least one memory including computer program code, wherein the at least one memory and the computer program code are configured, using the at least one processor, to cause the apparatus to at least: send a configuration to a user equipment, the configuration including an intra-secondary node conditional cell change associated with a source secondary node; receive an indication from the user equipment that the intra-secondary node conditional cell change has begun execution; and send a notification from the source secondary node to a master node related to a secondary cell group configuration associated with the intra-secondary node conditional cell change, the notification to the master node including an indication of whether the master node should forward the secondary cell group configuration to the user equipment.

[0106] An example apparatus includes at least one processor and at least one memory containing computer program code, wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus to at least receive a master node-initiated conditional cell change configuration or receive an intra-secondary node conditional cell change configuration associated with a source secondary node; receive an indication of a preference to reinitialize the master node-initiated conditional cell change after a user equipment has initiated an intra-secondary node conditional cell change execution; receive instructions from the source secondary node to continue inter-secondary node cell change evaluation based on the preference after the user equipment has initiated an intra-secondary node conditional cell change execution until expiration of a timer; start a timer for intra-secondary node conditional cell change execution after receiving the instruction to continue; monitor received signaling for at least one command for modification to the at least one pending conditional cell addition or change configuration; and release the at least one pending conditional cell addition or change configuration in response to not receiving the at least one command.

[0107] An exemplary apparatus includes means for transmitting a configuration to a user equipment, the configuration including a master node initiated conditional cell change, and means for transmitting a notification from the master node to a source secondary node in response to preparing the conditional cell change, the notification relating to the master node initiated conditional cell change, the notification including an indication of whether the source secondary node should perform an early data transfer from the source secondary node to the target secondary node.

[0108] An exemplary apparatus includes: means for transmitting a configuration to a user equipment, the configuration including an intra-secondary node conditional cell change associated with a source secondary node; means for receiving an indication from the user equipment that the intra-secondary node conditional cell change has begun execution; and means for transmitting a notification from the source secondary node to a master node, the notification to the master node related to a secondary cell group configuration associated with the intra-secondary node conditional cell change, the notification to the master node including an indication of whether the master node should forward the secondary cell group configuration to the user equipment.

[0109] An exemplary apparatus includes means for receiving a master node initiated conditional cell change configuration or receiving an intra-secondary node conditional cell change configuration associated with a source secondary node; means for receiving an indication of a preference to reinitialize the master node initiated conditional cell change after a user equipment initiates an intra-secondary node conditional cell change execution; means for receiving an instruction from the source secondary node to continue inter-secondary node cell change evaluation based on the preference after the user equipment initiates an intra-secondary node conditional cell change execution until expiration of a timer; means for starting a timer for intra-secondary node conditional cell change execution after receiving the instruction to continue; means for monitoring received signaling for at least one command for modification to at least one pending conditional cell addition or change configuration; and means for releasing the at least one pending conditional cell addition or change configuration in response to not receiving the at least one command.

[0110] An exemplary machine-readable non-transitory program storage device is provided that tangibly embodies a program of instructions executable by the machine to perform operations, the operations including: transmitting a configuration to a user equipment, the configuration including a master node-initiated conditional cell change; and transmitting a notification from the master node to a source secondary node in response to preparing the conditional cell change, the notification relating to the master node-initiated conditional cell change, the notification including an indication of whether the source secondary node should perform an early data transfer from the source secondary node to the target secondary node.

[0111] An exemplary machine-readable non-transitory program storage device is provided that tangibly embodies a program of instructions executable by the machine to perform operations, the operations including: transmitting a configuration to a user equipment, the configuration including an intra-secondary node conditional cell change associated with a source secondary node; receiving an indication from the user equipment that the intra-secondary node conditional cell change has begun execution; and transmitting a notification from the source secondary node to a master node, the notification to the master node related to a secondary cell group configuration associated with the intra-secondary node conditional cell change, the notification to the master node including an indication of whether the master node should forward the secondary cell group configuration to the user equipment.

[0112] An exemplary machine-readable non-transitory program storage device is provided that tangibly embodies a program of instructions executable by a machine to perform operations, the operations including receiving a master node-initiated conditional cell change configuration or receiving an intra-secondary node conditional cell change configuration associated with a source secondary node; receiving an indication of a preference to reinitialize the master node-initiated conditional cell change after a user equipment has initiated an intra-secondary node conditional cell change execution; receiving an instruction from the source secondary node to continue inter-secondary node cell change evaluation based on the preference after the user equipment has initiated an intra-secondary node conditional cell change execution until expiration of a timer; starting a timer for intra-secondary node conditional cell change execution after receiving the instruction to continue; monitoring received signaling for at least one command for modification to the at least one pending conditional cell addition or change configuration; and releasing the at least one pending conditional cell addition or change configuration in response to not receiving the at least one command.

[0113] It should be understood that the foregoing description is merely illustrative. Various alternatives and modifications may be devised by those skilled in the art. For example, features recited in various dependent claims may be combined with each other in any suitable combination. In addition, features from different embodiments described above may be selectively combined to form new embodiments. Accordingly, this description is intended to embrace all such alternatives, modifications, and variations that fall within the scope of the appended claims.

[0114] When a reference number used herein is of the form yx, this means that the referenced item is an instantiation (or type) of reference number y. For example, MN 170-1 and source SN 170-2 in Figures 2 and 3 are instantiations (e.g., first and second instantiations) of gNB 170 shown in Figure 1.

[0115] The following acronyms and abbreviations that may be found in the specification and / or drawings are defined as follows: 3GPP 3rd Generation Partnership Project 4G 4th Generation 5G (5th Generation) 5GC 5G Core Network AMF Access and Mobility Management Functions ASIC Application Specific Integrated Circuit CHO Conditional Handover CPAC Conditional PS Cell Addition / Change CPC Conditional PS Cell Change CPU Central Processing Unit CU Central Unit or Centralized Unit DC Dual Connectivity DCCH Dedicated Control Channel DSP Digital Signal Processor DU Distributed Unit eNB Evolved Node B (e.g., LTE base station) EN-DC E-UTRA-NR dual connectivity en-gNB: A node that provides NR user plane and control plane protocol termination for UEs and acts as a secondary node in the EN-DC. E-UTRA Evolved Universal Terrestrial Radio Access, i.e. LTE radio access technology F1 Control interface between CU and DU FPGA Field Programmable Gate Array gNB: A base station for 5G / NR, i.e., a node that provides NR user plane and control plane protocol termination for UEs and is connected to 5GC via the NG interface. HO Handover IE Information Elements I / F interface I / O Input / Output LMF location management function LTE Long Term Evolution (4G) MAC Media Access Control MME Mobility Management Entity MN Master Node, e.g., MgNB or MeNB MRM Multi-RAT Mobility NAS non-access layer NCE Network Control Element ng or NG New Generation ng-eNB New generation eNB NG-RAN New Generation Radio Access Network NR New Radio (5G) N / W Network PSCell Primary Secondary Cell PDA Personal Digital Assistant PDCP Packet Data Convergence Protocol PHY physical layer RAN Radio Access Network RAN2 RAN WG2 RAN3 RAN WG3 Rel Release RLC Radio Link Control RRC Radio Resource Control (protocol) RRH Remote Radio Head RU Wireless Unit Rx Receiver or receiver SCG Secondary Cell Group SGW Serving Gateway SN Secondary Node, e.g., en-gNB SON Self-organizing / optimizing network SRB1 Signalling Radio Bearer (for RRC messages (which may include NAS messages) and for NAS messages before the establishment of SRB2, using the DCCH logical channel) SRB2 Signalling Radio Bearer (for NAS messages using the DCCH logical channel). SRB2 has a lower priority than SRB1 and is configured by the network after security activation. SRB3 Signalling Radio Bearer (for specific RRC messages when the UE is in EN-DC using the DCCH logical channel) TEID Tunnel End Point Identifier TRP sending and / or receiving points TS Technical Specifications Tx Transmitter or Transmit UE User Equipment (e.g., wireless, typically mobile device) UPF User Plane Function WG Working Group X2 Network interface between RAN nodes and between RAN and core network Network interface between Xn NG-RAN nodes

Claims

1. 1. A method (500) comprising: transmitting (502), by a master node (170-1) to a user equipment (110), the configuration including a conditional cell change initiated by the master node; sending (504), by the master node, a notification to a source secondary node (170-2) in response to preparing the conditional cell change, the notification relating to the conditional cell change initiated by the master node; Including, the notification includes an indication of whether the source secondary node (170-2) should perform an early data transfer from the source secondary node to the target secondary node (506), the indication of whether the source secondary node should perform an early data transfer includes the presence or absence of a parameter, the presence of the parameter having a first value indicating that an early data transfer should be performed from the source secondary node to the target secondary node, and the absence of the parameter or the parameter having a second value indicating that an early data transfer should not be performed from the source secondary node to the target secondary node; and indicating, by the master node, to the user equipment, a preference for reinitializing the conditional cell change initiated at the master node after the user equipment initiates execution of an intra-secondary node conditional cell change; after the user equipment has initiated the intra-secondary node conditional cell change execution until expiry of a timer, the source secondary node instructs the user equipment to continue inter-secondary node cell change evaluation based on the preference; and wherein, after receiving the instruction to continue, the user equipment starts a timer for the execution of the intra-secondary node conditional cell change, the user equipment monitors received signaling for at least one command for modification to at least one pending conditional cell addition or modification configuration, and in response to not receiving the at least one command, the user equipment releases the at least one pending conditional cell addition or modification configuration.

2. The method (500) of claim 1 , wherein the conditional cell change comprises a conditional primary-secondary cell change.

3. the notification including the indication of whether the source secondary node should perform an early data transfer; modification required procedure or message, address indication procedures or messages, or New messages or procedures, 3. The method (500) of claim 1 or 2, wherein the signal is transmitted using at least one of:

4. 2. The method (500) of claim 1, wherein the notification related to the conditional cell change initiated by the master node is sent to the source secondary node when the source secondary node is not configured for early data forwarding.

5. 5. The method (500) of claim 4, wherein the source secondary node is not configured with early data forwarding due to the source secondary node not being configured with a packet data convergence protocol.

6. and further comprising receiving, by the master node, a notification related to a secondary cell group configuration from the source secondary node after the user equipment initiates execution of an intra-secondary node conditional cell change; the notification received from the source secondary node includes an indication of whether a secondary cell group configuration should be transferred from the master node to the user equipment. The method (500) of claim 1.

7. the notification received from the source secondary node: modification required message or procedure, or New messages or procedures, 7. The method (500) of claim 6, wherein the signal is received using at least one of:

8. 8. The method (500) of claim 6 or 7, further comprising: transferring, by the master node, the secondary cell group configuration to the user equipment based on the indication of whether the secondary cell group configuration should be transferred from the master node to the user equipment, or not transferring the secondary cell group configuration to the user equipment.

9. 7. The method (500) of claim 6, wherein the indication of whether the secondary cell group configuration should be transferred from the master node to the user equipment comprises the presence or absence of a parameter, the presence of the parameter having a first value indicating to the master node that the secondary cell group configuration should be transferred from the master node to the user equipment, and the absence of the parameter or the parameter having a second value indicating to the master node that the secondary cell group configuration should not be transferred from the master node to the user equipment.

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