SPR configuration and reporting for MN-initiated pscell change and cpc

Abstract

A UE, connected towards cellular network(s) via a PCell provided by a MN and a PSCell provided by a SN, determines information related to value(s) of timer(s) associated with a connection status of the UE towards the PSCell. The UE generates, in case of a PSCell change procedure, a related successful PSCell change report including configured timer value(s) associated with the PSCell based at least on the information. The UE sends, towards a node of the cellular network(s), the generated successful PSCell change report including the configured timer value(s) associated with the PSCell. The node receives the successful PSCell change report including configured timer value(s) associated with a PSCell. The node stores information including the configured timer value(s) associated with the PSCell.

Description

SPR Configuration and Reporting for MN-Initiated PSCell Change and CPCTECHNICAL FIELD

[0001] Examples of embodiments herein relate generally to wireless communications and, more specifically, relate to changes in cells between master nodes (MNs) and secondary nodes (SNs).BACKGROUND

[0002] A UE undergoes mobility, which is where it moves between cells and has to transfer connection from one cell to another cell. One such time when mobility can occur is in Multi-RAT (multi-radio access technology) Dual Connectivity (MR-DC), which is where a Master Node (MN) functions as the controlling entity that provides control plane connection to the core network, and utilizes a Secondary Node (SN) for additional resources to the UE.

[0003] Typically, there is a primary secondary cell (PSCell) that is one of the SNs and that is part of a secondary cell group (SCG) and is the primary cell of that group. This PSCell can be changed for mobility purposes, such that the PSCell is moved between SNs. For instance, the MN can initial a PSCell change between SNs for a number of reasons, such as an A4 event, when a neighboring cell becomes better than a threshold. Another possibility is inter- SN Conditional PSCell Change (CPC) initiated by the MN. Yet another possibility is an SN- initiated SN change, which causes a change to the PSCell. This SN-initiated change can also be conditional and falls into a CPC to the PSCell.

[0004] These changes may be reported using a Successful PSCell Change Report (SPR). The UE is configured by the network with SPR configuration, and the UE can report what happens during PSCell changes using the SPR. While there are benefits to using the SPR, the use could be improved.BRIEF SUMMARY

[0005] This section is intended to include examples and is not intended to be limiting.

[0006] In an exemplary embodiment, a method is disclosed that includes determining, by a user equipment connected towards at least one cellular network via a primary cell provided by a master node and a primary secondary cell provided by a secondary node, information related to at least one value of at least one timer associated with a connection status of the user equipment towards the primary secondary cell; generating, by the user equipment, in case of a primary secondary cell change procedure, a related successful primary secondary cell change report including at least one configured timer value associated with the primary secondary cell based at least on the information; and sending, by the user equipment towards a node of the at least one cellular network, the generated successful primary secondary cell change report including the at least one configured timer value associated with the primary secondary cell.

[0007] An additional exemplary embodiment includes a computer program, comprising instructions for performing the method of the previous paragraph, when the computer program is run on an apparatus. The computer program according to this paragraph, wherein the computer program is a computer program product comprising a computer-readable medium bearing the instructions embodied therein for use with the apparatus. Another example is the computer program according to this paragraph, wherein the program is directly loadable into an internal memory of the apparatus.

[0008] An exemplary apparatus includes one or more processors and one or more memories storing instructions that, when executed by the one or more processors, cause the apparatus at least to perform: determining, by a user equipment connected towards at least one cellular network via a primary cell provided by a master node and a primary secondary cell provided by a secondary node, information related to at least one value of at least one timer associated with a connection status of the user equipment towards the primary secondary cell; generating, by the user equipment, in case of a primary secondary cell change procedure, a related successful primary secondary cell change report including at least one configured timer value associated with the primary secondary cell based at least on the information; and sending, by the user equipment towards a node of the at least one cellular network, the generated successful primary secondary cell change report including the at least one configured timer value associated with the primary secondary cell.

[0009] An exemplary computer program product includes a computer-readable storage medium bearing instructions that, when executed by an apparatus, cause the apparatus to perform at least the following: determining, by a user equipment connected towards at least one cellular network via a primary cell provided by a master node and a primary secondary cell provided by a secondary node, information related to at least one value of at least one timer associated with a connection status of the user equipment towards the primary secondary cell; generating, by the user equipment, in case of a primary secondary cell change procedure, a related successful primary secondary cell change report including at least one configured timer value associated with the primary secondary cell based at least on the information; and sending, by the user equipment towards a node of the at least one cellular network, the generated successful primary secondary cell change report including the at least one configured timer value associated with the primary secondary cell.

[0010] In another exemplary embodiment, an apparatus comprises means for performing: determining, by a user equipment connected towards at least one cellular network via a primary cell provided by a master node and a primary secondary cell provided by a secondary node, information related to at least one value of at least one timer associated with a connection status of the user equipment towards the primary secondary cell; generating, by the user equipment, in case of a primary secondary cell change procedure, a related successful primary secondary cell change report including at least one configured timer value associated with the primary secondary cell based at least on the information; and sending, by the user equipment towards a node of the at least one cellular network, the generated successful primary secondary cell change report including the at least one configured timer value associated with the primary secondary cell.

[0011] In an exemplary embodiment, a method is disclosed that includes receiving, by a node that provides a primary cell as a master node to a user equipment in at least one cellular network, a successful primary secondary cell change report including at least one configured timer value associated with a primary secondary cell, wherein a secondary node provides the primary secondary cell to the user equipment; and storing, by the node, information comprising the at least one configured timer value associated with the primary secondary cell.

[0012] An additional exemplary embodiment includes a computer program, comprising instructions for performing the method of the previous paragraph, when the computer program is run on an apparatus. The computer program according to this paragraph, wherein the computer program is a computer program product comprising a computer-readable medium bearing the instructions embodied therein for use with the apparatus. Another example is the computer program according to this paragraph, wherein the program is directly loadable into an internal memory of the apparatus.

[0013] An exemplary apparatus includes one or more processors and one or more memories storing instructions that, when executed by the one or more processors, cause the apparatus at least to perform: receiving, by a node that provides a primary cell as a master node to a user equipment in at least one cellular network, a successful primary secondary cell change report including at least one configured timer value associated with a primary secondary cell, wherein a secondary node provides the primary secondary cell to the user equipment; and storing, by the node, information comprising the at least one configured timer value associated with the primary secondary cell.

[0014] An exemplary computer program product includes a computer-readable storage medium bearing instructions that, when executed by an apparatus, cause the apparatus to perform at least the following: receiving, by a node that provides a primary cell as a master node to a user equipment in at least one cellular network, a successful primary secondary cell change report including at least one configured timer value associated with a primary secondary cell, wherein a secondary node provides the primary secondary cell to the user equipment; and storing, by the node, information comprising the at least one configured timer value associated with the primary secondary cell.

[0015] In another exemplary embodiment, an apparatus comprises means for performing: receiving, by a node that provides a primary cell as a master node to a user equipment in at least one cellular network, a successful primary secondary cell change report including at least one configured timer value associated with a primary secondary cell, wherein a secondary node provides the primary secondary cell to the user equipment; and storing, by thenode, information comprising the at least one configured timer value associated with the primary secondary cell.BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In the attached drawings:

[0017] FIG. 1 is a signaling diagram of a SN change procedure that is MN-initiated;

[0018] FIG. 2 is a signaling diagram of conditional SN change procedure that is MN- initiated;

[0019] FIG. 3 is a signaling diagram of SN change procedure that is SN initiated;

[0020] FIG. 4, split over FIGS. 4A and 4B, is a signaling diagram of conditional SN change procedure that is SN initiated;

[0021] FIG. 5 is a logic flow diagram of an overview of an example method for SPR configuration and reporting for MN-initiated PSCell change and CPC;

[0022] FIG. 6 is a logic flow diagram of a first phase of SPR configuration and reporting for MN-initiated PSCell change and CPC;

[0023] FIG. 7 is a logic flow diagram of a second phase of SPR configuration and reporting for MN-initiated PSCell change and CPC;

[0024] FIG. 8 is an example of an IE for a “T310 / 312 timers and threshold Request” message;

[0025] FIG. 9 is an example of an IE for a “T310 / 312 timers and threshold Answer” message; and

[0026] FIG. 10 is a block diagram of one possible and non-limiting exemplary system in which the exemplary embodiments may be practiced.DETAILED DESCRIPTION OF THE DRAWINGS

[0027] Abbreviations that may be found in the specification and / or the drawing figures are defined below, at the end of the detailed description section.

[0028] The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any embodiment described herein as “exemplary” is not necessarily tobe construed as preferred or advantageous over other embodiments. All of the embodiments described in this Detailed Description are exemplary embodiments provided to enable persons skilled in the art to make or use the invention and not to limit the scope of the invention which is defined by the claims.

[0029] When more than one drawing reference numeral, word, or acronym is used within this description withand in general as used within this description, the “ / ” may be interpreted as “or”, “and”, or “both”. As used herein, “at least one of the following: ” and “at least one of ” and similar wording, where the list of two or more elements are joined by “and” or “or,” mean at least any one of the elements, or at least any two or more of the elements, or at least all the elements.

[0030] As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises”, “comprising”, “has”, “having”, “includes” and / or “including”, when used herein, specify the presence of stated features, elements, and / or components etc., but do not preclude the presence or addition of one or more other features, elements, components and / or combinations thereof.

[0031] Any flow diagram (such as FIGS. 5-7) or signaling diagram (such as FIGS. 1- 4) herein is considered to be a logic flow diagram, and illustrates the operation of an exemplary method, results of execution of computer program instructions embodied on a computer readable memory, functions performed by logic implemented in circuitry, and / or interconnected means for performing functions in accordance with an exemplary embodiment. Block diagrams (such as FIG. 10) also illustrate the operation of an exemplary method, results of execution of computer program instructions embodied on a computer readable memory, functions performed by logic implemented in circuitry, and / or interconnected means for performing functions in accordance with an exemplary embodiment.

[0032] Examples herein relate to mobile communication systems. Description of technology that is helpful to understand the examples herein is now presented. The next sections have headings for ease of reference.

[0033] 1. Mobility in MR-DC

[0034] In case of Multi -RAT Dual Connectivity (MR-DC), a Master Node (MN) functions as the controlling entity that provides control plane connection to the core network, and utilizes a Secondary Node (SN) for additional resources to the UE. Secondary Cell Group (SCG) refers to a group of serving cells associated with the SN, and comprises a Primary Secondary Cell (PSCell), which is the primary cell of the SCG.

[0035] 1.1 MN-initiated SN change

[0036] The steps to perform MN-initiated SN change may be described through FIG. 1, FIG. 1 is a signaling diagram of a SN change procedure - MN-initiated (see 3 GPP TS 37.340 V17.6.0 (2023-09), Figure 10.5.2-1). FIG. 1 shows a UE 10 connected to a cellular network 1, which comprises the MN 70-1, a S-SN (source SN) 70-2, a T-SN (target SN) 70-3, a UPF 99-1, and an AMF 99-2.

[0037] The SN change initiated by the MN 70-1 will result in a PSCell change from the Source-SN (S-SN) 70-2 to the Target-SN (T-SN) 70-3. An example signaling flow of this procedure is shown in FIG. 1. This is an extract from 3GPP TS 37.340 with some additional details and is as follows.

[0038] 1 / 2. The trigger for PSCell could be an A4 event (when a neighboring cell becomes better than a threshold), upon which the UE 10 sends an A4 measurement report to the MN 70-1 which is hidden from the SN 70-2. The MN initiates the SN change by requesting the target SN to allocate resources for the UE by means of the SN Addition procedure. The MN 70-1 may include measurement results related to the target SN 70-3. If data forwarding is needed, the target SN 70-3 provides data forwarding addresses to the MN 70-1. The target SN 70-3 includes the indication of the full or delta RRC configuration.

[0039] NOTE 1: The MN 70-1 may trigger the MN-initiated SN Modification procedure (to the source SN) to retrieve the current SCG configuration and to allow provision of data forwarding related information before step 1.

[0040] 2a. For SN terminated bearers using MCG resources, the MN provides Xn-UDL TNL address information in the Xn-U Address Indication message.

[0041] 3. If the allocation of target SN resources was successful, the MN 70-1 initiates the release of the source SN resources including a cause indicating SCG mobility. TheSource SN may reject the release. If data forwarding is needed, the MN 70-1 provides data forwarding addresses to the source SN 70-2. If direct data forwarding is used for SN-terminated bearers, the MN 70-1 provides data forwarding addresses as received from the target SN 70-3 to source SN 70-2. Reception of the SN Release Request message triggers the source SN 70-2 to stop providing user data to the UE 10.

[0042] 4 / 5. The MN 70-1 triggers the UE 10 to apply the new configuration. The MN indicates the new configuration to the UE in the MN RRC reconfiguration message including the target SN RRC reconfiguration message. The UE 10 applies the new configuration and sends the MN RRC reconfiguration complete message, including the SN RRC response message for the target SN, if needed. In case the UE is unable to comply with (part of) the configuration included in the MN RRC reconfiguration message, the UE 10 performs the reconfiguration failure procedure.

[0043] 6. If the RRC connection reconfiguration procedure was successful, the MN informs the target SN via SN Reconfiguration Complete message with the included SN RRC response message for the target SN, if received from the UE.

[0044] 7. If configured with bearers requiring SCG radio resources the UE synchronizes to the target SN via a random access procedure.

[0045] 8. If PDCP termination point is changed for bearers using RLC AM, the source SN sends the SN Status Transfer message, which the MN sends then to the target SN, if needed.

[0046] 9. If applicable, data forwarding from the source SN 70-2 to the T-SN 70-3 takes place. It may be initiated as early as the source SN receives the SN Release Request message from the MN.

[0047] 10. The source SN sends the Secondary RAT Data Usage Report message to the MN and includes the data volumes delivered to and received from the UE as described in clause 10.11.2 of 3GPP TS 37.340.

[0048] NOTE 2: The order the SN sends the Secondary RAT Data Usage Report message and performs data forwarding with MN is not defined. The SN may send the report when the transmission of the related QoS flow is stopped.

[0049] 11 -15. If applicable, a PDU Session path update procedure is triggered by theMN.

[0050] 16. Upon reception of the UE Context Release message, the source SN releases radio and C-plane related resources associated to the UE context. Any ongoing data forwarding may continue.

[0051] 1.2 MN-initiated SN Conditional PSCell Change

[0052] In addition to inter-SN MN-initiated PSCell change, there can be also inter- SN Conditional PSCell Change (CPC) initiated by MN as described in the chapter 10.5.2, Figure 10.5.2-3 in the 3GPP TS 37.340. The same is shown in FIG. 2. This figure, relative to FIG. 1, includes another potential T-SN 70-4. An extract from 3GPP TS 37.340 for Conditional SN change procedure - MN-initiated details is as follows.

[0053] 1 / 2. The MN initiates the conditional SN change by requesting the candidateSN(s) to allocate resources for the UE by means of the SN Addition procedure, indicating that the request is for CP AC. The MN also provides the candidate cells recommended by MN via the latest measurement results for the candidate SN(s) to choose and configure the SCG cell(s), provides the upper limit for the number of PSCells that can be prepared by the candidate SN. Within the list of cells as indicated within the measurement results indicated by the MN, the candidate SN decides the list of PSCell(s) to prepare (considering the maximum number indicated by the MN) and, for each prepared PSCell, the candidate SN decides other SCG SCells and provides the new corresponding SCG radio resource configuration to the MN in an NR RRCReconfiguration** message contained in the SN Addition Request Acknowledge message with the prepared PSCell ID(s). It is noted that the asterisks, such as *, **, or *** along with their corresponding messages are used in the specification, 3 GPP TS 27.340. If data forwarding is needed, the candidate SN provides data forwarding addresses to the MN. The candidate SN includes the indication of the full or delta RRC configuration. The candidate SN can either accept or reject each of the candidate cells listed within the measurement results indicated by the MN, i.e., the candidate SN cannot configure any alternative candidates.

[0054] NOTE 4: The MN may trigger the MN-initiated SN Modification procedure (to the source SN) to retrieve the current SCG configuration and to allow provision of data forwarding related information before step 1.

[0055] 2a. For SN terminated bearers using MCG resources, the MN provides Xn-UDL TNL address information in the Xn-U Address Indication message to the candidate SN(s).

[0056] 3. The MN sends to the UE an RRCReconfiguration message including theCPC configuration, i.e., a list of RRCReconfiguration* messages and associated execution conditions, in which each RRCReconfiguration* message contains the SCG configuration in the RRCReconfiguration** message received from the candidate SN in step 2 and possibly an MCG configuration. Besides, the RRCReconfiguration message can also include an updated MCG configuration, e.g., to configure the required conditional measurements.

[0057] 4. The UE applies the RRCReconfiguration message received in step 3, stores the CPC configuration and replies to the MN with an RRCReconfigurationComplete message. In case the UE is unable to comply with (part of) the configuration included in the RRCReconfiguration message, the UE performs the reconfiguration failure procedure.

[0058] 4a. Upon receiving the MN RRCReconfigurationComplete message from theUE, the MN informs the source SN that the CPC has been configured via Xn-U Address Indication procedure, the source SN, if applicable, together with the Early Status Transfer procedure, starts early data forwarding. The PDCP SDU forwarding may take place during early data forwarding.

[0059] NOTE 4a: Separate Xn-U Address Indication procedures may be invoked to provide different forwarding addresses of the prepared candidate target SNs. In this case, it is up to the MN and the source SN implementations to make sure that the EARLY STATUS TRANSFER message(s) from the source SN, if any, is forwarded to the right target destination. The Xn-U Address Indication procedure may further be invoked to indicate to the source SN to stop already initiated early data forwarding for some SN-terminated bearers if they are no longer subject to data forwarding due to the modification or cancellation of the prepared conditional SN change procedures.

[0060] NOTE 4b: For the early transmission of MN terminated split / SCG bearers, the MN forwards the PDCP PDU to the candidate SN(s).

[0061] 5. The UE starts evaluating the execution conditions. If the execution condition of one candidate PSCell is satisfied, the UE applies RRCReconfiguration* message corresponding to the selected candidate PSCell, and sends an MN RRCReconfigurationComplete* message, including an NR RRCReconfigurationComplete** message for the selected candidate PSCell, and information enabling the MN to identify the SN of the selected candidate PSCell.

[0062] 6a-6c. The MN triggers the MN-initiated SN Release procedure to inform the source SN to stop providing user data to the UE, and if applicable, triggers the Xn-U Address Indication procedure to inform the source SN the address of the SN of the selected candidate PSCell, to start late data forwarding.

[0063] 7a-7c. If the RRC connection reconfiguration procedure was successful, theMN informs the SN of the selected candidate PSCell via SN Reconfiguration Complete message, including the SN RRCReconfigurationComplete** message. The MN sends the SN Release Request message(s) to cancel CPC in the other candidate SN(s), if configured. The other candidate SN(s) acknowledges the release request.

[0064] 8. The UE synchronizes to the PSCell indicated in the RRCReconfiguration* message applied in step 5.

[0065] 9a-9b. If PDCP termination point is changed for bearers using RLC AM, the source SN sends the message, which the MN sends then to the SN of the selected candidate PSCell, if needed.

[0066] 10. If applicable, data forwarding from the source SN takes place. It may be initiated as early as the source SN receives the early data forwarding address in step 4a.

[0067] 11. The source SN sends the Secondary RAT Data Usage Report message to the MN and includes the data volumes delivered to and received from the UE as described in clause 10.11.2.

[0068] NOTE 5: The order the SN sends the Secondary RAT Data Usage Report message and performs data forwarding with MN is not defined. The SN may send the report when the transmission of the related QoS flow is stopped.

[0069] 12-16. If applicable, a PDU Session path update procedure is triggered by theMN.

[0070] 17. Upon reception of the UE Context Release message, the source SN releases radio and C-plane related resources associated to the UE context. Any ongoing data forwarding may continue.

[0071] 1.3 SN-initiated SN change

[0072] Apart from MN-initiated PSCell change, there is also SN-initiated PSCell change as described in the section 10.5.2, Figure 10.5.2-2. FIG. 3 is a signaling diagram of SN change procedure that is SN initiated (3GPP TS 37.340, Figure 10.5.2-2).

[0073] An example signaling flow for SN initiated PSCell change is shown in FIG. 3. This uses the same entities as in FIG. 1.

[0074] 1. The source SN initiates the SN change procedure by sending the SNChange Required message, which contains a candidate target node ID and may include the SCG configuration (to support delta configuration) and measurement results related to the target SN.

[0075] 2 / 3. The MN requests the target SN to allocate resources for the UE by means of the SN Addition procedure, including the measurement results related to the target SN received from the source SN. If data forwarding is needed, the target SN provides data forwarding addresses to the MN. The target SN includes the indication of the full or delta RRC configuration.

[0076] 3a. For SN terminated bearers using MCG resources, the MN provides Xn-UDL TNL address information in the Xn-U Address Indication message.

[0077] 4 / 5. The MN triggers the UE to apply the new configuration. The MN indicates the new configuration to the UE in the MN RRC reconfiguration message including the SN RRC reconfiguration message generated by the target SN. The UE applies the new configuration and sends the MN RRC reconfiguration complete message, including the SN RRC response message for the target SN, if needed. In case the UE is unable to comply with (part of)the configuration included in the MN RRC reconfiguration message, it performs the reconfiguration failure procedure.

[0078] 6. If the allocation of target SN resources was successful, the MN confirms the change of the source SN. If data forwarding is needed, the MN provides data forwarding addresses to the source SN. If direct data forwarding is used for SN terminated bearers, the MN provides data forwarding addresses as received from the target SN to source SN. Reception of the SN Change Confirm message triggers the source SN to stop providing user data to the UE and, if applicable, to start data forwarding.

[0079] 7. If the RRC connection reconfiguration procedure was successful, the MN informs the target SN via SN Reconfiguration Complete message with the included SN RRC response message for the target SN, if received from the UE.

[0080] 8. The UE synchronizes to the target SN.

[0081] 9. If PDCP termination point is changed for bearers using RLC AM, the source SN sends the SN Status Transfer message, which the MN sends then to the target SN, if needed.

[0082] 10. If applicable, data forwarding from the source SN takes place. It may be initiated as early as the source SN receives the SN Change Confirm message from the MN.

[0083] 11. The source SN sends the Secondary RAT Data Usage Report message to the MN and includes the data volumes delivered to and received from the UE as described in clause 10.11.2 of 3GPP TS 37.340.

[0084] NOTE 3: The order the SN sends the Secondary RAT Data Usage Report message and performs data forwarding with MN / target SN is not defined. The SN may send the report when the transmission of the related QoS flow is stopped.

[0085] 12-16. If applicable, a PDU Session path update procedure is triggered by theMN.

[0086] 17. Upon reception of the UE Context Release message, the source SN releases radio and C-plane related resources associated to the UE context. Any ongoing data forwarding may continue.

[0087] 1.4 SN-initiated SN Conditional PSCell Change

[0088] Similar to MN-initiated SN-conditional PSCell Change, a mobility procedure of SN-conditional PSCell Change, initiated by an SN is defined in section 10.5.2 in 3GPP TS 37.340. An example signaling flow for SN initiated conditional PSCell change is shown in FIG. 4. This uses the same entities as were used in FIG. 2.

[0089] 1. The source SN initiates the conditional SN change procedure by sending the SN Change Required message, which contains a CPC initiation indication. The message also contains candidate node ID(s) and may include the SCG configuration (to support delta configuration), and contains the measurements results which may include cells that are not CPC candidates. The message also includes a list of proposed PSCell candidates recommended by the source SN, including execution conditions, the upper limit for the number of PSCells that can be prepared by each candidate SN, and may also include the SCG measurement configurations for CPC (e.g., measurement ID(s) to be used for CPC).

[0090] 2 / 3. The MN requests each candidate SN(s) (70-3 and 70-4 in this example) to allocate resources for the UE by means of the SN Addition procedure(s), indicating the request is for CP AC, and the measurements results which may include cells that are not CPC candidates received from the source SN to the candidate SN, and indicating a list of proposed PSCell candidates received from the source SN, but not including execution conditions. Within the list of PSCells suggested by the source SN, the candidate SN decides the list of PSCell(s) to prepare (considering the maximum number indicated by the MN) and, for each prepared PSCell, the candidate SN decides SCG SCells and provides the new corresponding SCG radio resource configuration to the MN in an NR RRCReconfiguration* * message contained in the SgNB Addition Request Acknowledge message. If data forwarding is needed, the candidate SN provides data forwarding addresses to the MN. The candidate SN includes the indication of full or delta RRC configuration, and the list of prepared PSCell IDs to the MN. The candidate SN can either accept or reject each of the candidate cells suggested by the source SN, i.e., the candidate SN cannot configure any alternative candidates.

[0091] 3a. For SN-terminated bearers using MCG resources, the MN provides Xn-UDL TNL address information in the Xn-U Address Indication message to the candidate SN(s).

[0092] 4 / 5. The MN may indicate the candidate PSCells accepted by each candidateSN to the source SN via SN Modification Request message before it configures the UE, e.g., when not all candidate PSCells were accepted by the candidate SN(s). If the MN does not send such indication, step 4 and 5 are skipped. If requested, the source SN sends an SN Modification Request Acknowledge message and if needed, provides an updated measurement configurations and / or the execution conditions to the MN.

[0093] 6. The MN sends to the UE an RRCReconfiguration message including theCPC configuration, i.e., a list of RRCReconfiguration* messages and associated execution conditions, in which each RRCReconfiguration* message contains the SCG configuration in the RRCReconfiguration** message received from the candidate SN in step 3 and possibly an MCG configuration. Besides, the RRCReconfiguration message can also include an updated MCG configuration, as well as the NR RRCReconfiguration*** message generated by the source SN, e.g., to configure the required conditional measurements.

[0094] 7. The UE applies the RRCReconfiguration message received in step 6, stores the CPC configuration and replies to the MN with an RRCReconfigurationComplete message, which can include an NR RRCReconfigurationComplete*** message. In case the UE is unable to comply with (part of) the configuration included in the RRCReconfiguration message, the UE performs the reconfiguration failure procedure.

[0095] 8. If an SN RRC response message is included, the MN informs the source SN with the SN RRCReconfigurationComplete*** message via SN Change Confirm message. If step 4 and 5 are skipped, the MN will indicate the candidate PSCells accepted by each candidate SN to the source SN in the SN Change Confirm message.

[0096] The MN sends the SN Change Confirm message towards the source SN to indicate that CPC is prepared, and in such case the source SN continues providing user data to the UE. If early data forwarding is applied, the MN informs the source SN the data forwarding addresses as received from the candidate SN(s), the source SN, if applicable, together with the Early Status Transfer procedure, starts early data forwarding. The PDCP SDU forwarding may take place during early data forwarding. In case multiple candidate SNs are prepared, the MN includes a list of Target SN ID(s) and list of data forwarding addresses to the source SN.

[0097] NOTE 5a: The Xn-U Address Indication procedure may further be invoked to indicate to the source SN to stop already initiated early data forwarding for some PDCP SDUs if they are no longer subject to data forwarding due to the modification or cancellation of the prepared conditional PSCell change.

[0098] NOTE 5b: For the early transmission of MN terminated split / SCG bearers, the MN forwads the PDCP PDU to the candidate SN(s).

[0099] 9a-9d. The source SN may send the SN Modification Required message to trigger an update of CPC execution condition and / or corresponding SCG measurement configuration for CPC. In such case in step 9b, the MN reconfigures the UE and in step 9c the UE responds with RRCReconfigurationComplete, similarly as in steps 6 and 7.

[0100] 10. The UE starts evaluating the execution conditions. If the execution condition of one candidate PSCell is satisfied, the UE applies RRCReconfiguration* message corresponding to the selected candidate PSCell, and sends an RRCReconfigurationComplete* message, including an RRCReconfigurationComplete** message for the selected candidate PSCell, and information enabling the MN to identify the SN of the selected candidate PSCell.

[0101] 1 la-11c. The MN triggers the MN-initiated SN Release procedure to inform the source SN to stop providing user data to the UE, and triggers the Xn-U Address Indication procedure to inform the source SN the address of the SN of the selected candidate PSCell and if applicable, starts late data forwarding.

[0102] 12a- 12c. If the RRC connection reconfiguration procedure was successful, theMN informs the SN of the selected candidate PSCell via SN Reconfiguration Complete message, including the SN RRCReconfigurationComplete** message. The MN sends the SN Release Request message(s) to cancel CPC in the other candidate SN(s), if configured. The other candidate SN(s) acknowledges the release request.

[0103] 13. The UE synchronizes to the PSCell indicated in the RRCReconfiguration* message applied in step 10.

[0104] 14. If PDCP termination point is changed for bearers using RLC AM, the source SN sends the SN Status Transfer message, which the MN sends then to the SN of the selected candidate PSCell, if needed.

[0105] 15. If applicable, data forwarding from the source SN takes place. It may be initiated as early as the source SN receives the data forwarding address related information from the MN.

[0106] 16. The source SN sends the Secondary RAT Data Usage Report message to the MN and includes the data volumes delivered to and received from the UE as described in clause 10.11.2 of 3GPP TS 37.340.

[0107] NOTE 6: The order the SN sends the Secondary RAT Data Usage Report message and performs data forwarding with MN / target SN is not defined. The SN may send the report when the transmission of the related QoS flow is stopped.

[0108] 17-21. If applicable, a PDU Session path update procedure is triggered by theMN.

[0109] 22. Upon reception of the UE Context Release message, the source SN releases radio and C-plane related resources associated to the UE context. Any ongoing data forwarding may continue.

[0110] 2. Successful PSCell Change Report (SPR)

[0111] As examples herein relate to SPR (a.k.a. SPCR), which was defined in 3 GPP Rel. 18 as follows. That is, successful PSCell Change Report (SPR) in Rel-18 may be described as follows.

[0112] Although an SN change initiated by MN may result in a PSCell change that may be successful, there may be still outages during the PSCell change. For instance, in case of CPC, timer T310 could have been running for some time before the CPC is successfully executed. In another example, the UE might not succeed to perform random access to the target PSCell from the first random access attempts. For these reasons, Successful PSCell Change Report (SPR) was introduced in Rel-18 to further optimize the timing of the PSCell change.

[0113] SPR configuration is sent within RRC Connection Reconfiguration message to the UE. The SPR is fetched by the receiving MN node using UEInformationRequest / UEInformationResponse procedure. In case the receiving MN is different than the initiating MN (which triggered the PSCell change), the SPR is forwarded back to the initiating MN node, by the ACCESS AND MOBILITY INDICATION message. If the UE has available SPR to bereported, the UE includes the “successHO-InfoAvailable” IE indicating the availability of SPR to the network in RRC Reconfiguration Complete message, i.e., RRCReconfigurationComplete, or RRCReestablishmentComplete, or RRCSetupComplete, or RRCResumeComplete message. The UE may discard the SPR, i.e., release the UE variable VarSuccHO-Report, 48 hours after the SPR is stored.

[0114] UE only logs SPR if configuration of SPR is received and at least one of the following criteria is / are satisfied:

[0115] 1) T310 timer of the UE exceeds the configured threshold by the source node,

[0116] 2) T312 timer of the UE exceeds the configured threshold by the source node, and / or

[0117] 3) T304 timer of the UE exceeds the configured threshold by the target node.

[0118] These timers are associated with connection status of the UE, e.g., towards an SN. Regarding timers in general, a timer might be used by the UE for different purposes. For instance, a timer may relate to or be associated with a connection status of the UE towards a PSCell, e.g., on the physical layer (layer 1). In case of physical layer problems, e.g., UE connection towards source PSCell, the UE may start a timer and until expiration of the timer is enabled to recover from the physical layer problems without the duty to, e.g., start a reestablishment action requiring additional signaling and delay and interruption of the connection.

[0119] Such timer as, e.g., used in 3 GPP TS 38 series could, e.g.. be further described as:

[0120] T310 - a timer used to allow the UE to recover physical layer problems on the source PSCell;

[0121] T312 - a timer used to allow measurement reporting for UE in physical layer problems on the source PSCell; or

[0122] T304 - a timer used for successful completion of random access on the targetPSCell.

[0123] A timer may be associated with a source PSCell, or a target PSCell, a PCell, or the like. A timer might be configured by the access node providing the respective Cell, e.g., a Secondary node SN providing a PSCell, e.g., source and / or target PSCell. Or a timer might havea pre-configured default value, or else. Further details, e.g.; related to definition of timers, use of timers, determination of UE actions based on timer status, may be found in the citations: sections 5.7.10, 6.3.2, 7.1.1, and 9.2.3 of 3GPP TS 38.331 vl7.6.0 (2023-06).

[0124] Note that there are separate (potentially in parallel) configurable thresholds for T310 / T312 / T304, and those can be percentage values of 40%, 60%, 80%. For threshold for T312, the percentage value also includes 20%. The percentage is to indicate the ratio of the threshold value (unit: ms) over the signaled T310 / T312 / T304 value (unit: ms). Note also that these timers are defined in chapter 7.1.1 of 3GPP TS 38.331.

[0125] The currently agreed content of SPR in Rel. 18 includes the following:

[0126] 1) Source and target cell IDs of the PSCell change,

[0127] 2) Latest radio link measurements of all measurement IDs available at the time PSCell change is executed for all handover types (including CPC),

[0128] 3) A cause that was the trigger for generating the SPCR, i.e., t310-cause, t312- cause, t304-cause,

[0129] 4) Latest radio measurement results of the candidate target cells in case of conditional PSCell change (CPC),

[0130] ) Time elapsed between CPC execution towards target cell and corresponding latest configuration received for the selected target cell,

[0131] 6) RA-InformationCommon when T304 is above a threshold,

[0132] 7) Available location information,

[0133] 8) CGI of PCell, and / or

[0134] 9) Indication of whether PSCell change is MN-initiated or SN-initiated.

[0135] 2. Current discussions

[0136] The MN-initiated PSCell change and CPC has been discussed over multiple RAN3 meetings. The outcome of the latest RAN3 # 121 bis meeting is following:

[0137] Views from multiple companies include that such assistance information is beneficial, not only for setting the T310 / 312 thresholds but also for consequent SPR related optimization. Other companies had a different view which may be summarized into the following points:

[0138] 1 ) the MN may not need to know the T310 / 312 threshold and timer values from source SN for proper SPR configuration. MN may decide on the T310 / 312 thresholds by itself even the time needed for finding the proper values may take some time.

[0139] 2) Even the knowing of the T310 / 312 timer values may be useful for MN for consequent optimization based on SPR, they do not see as proper solution to communicate the T310 / 312 timer values from SN to MN, which requires MN-initiated SN modification procedure for each MN-initiated PSCell change, as only a fraction of the executed PSCell changes will result into reporting SPR from UE to network.

[0140] 3. Issues with current technology

[0141] As stated above, the MN-initiated PSCell change is triggered by the MN as the change is based on the A4 measurement report, which is hidden for the SN. All the SPR configuration related to T310 / 312 thresholds may be provided by the MN without any further assistance information from Source-SN. One issue is that even the T310 / 312 timers are known by UE as they are communicated via ue-TimersAndConstants received in SIB1 in PSCell level or rlf-TimersAndConstants per individual UE (see 3GPP TS 38.331) they are hidden for the MN. However, it is important for the MN to know the T310 / 312 timer values to properly tune the T310 / 312 thresholds and consequently provide optimization related to SPR. As described above,providing the assistance information from source SN to MN for MN-initiated PSCell change is a possible improvement, but, due to opposing view of some companies, this might not be implemented.

[0142] 4. Overview of the examples

[0143] Examples herein provide an alternative way of providing the assistance information to MN. For instance, one example provides assistance information in the form of used T310 / 312 threshold and timer values to the MN in case of MN-initiated PSCell change or CPC, which is based on storing (e.g., in a database of) T310 / 312 threshold and timer values per source PSCell and per UE (in case the T312 / 310 thresholds and timers are UE relevant) in the MN. This may be achieved in two phases, which are also described by FIG. 5, which is a logic flow diagram of an overview of an example method for SPR configuration and reporting for MN-initiated PSCell change and CPC.

[0144] Phase 1 550: The UE in block 510 logs information in the SPR that is delivered to the network (e.g., MN). Examples of the information include the following:

[0145] 1) the used T310 / 312 thresholds in case of SN initiated PSCell change, see block 520; and / or

[0146] 2) T310 / 312 timer values for all PScell changes (MN or SN initiated), see block 530.

[0147] Phase 2 560: the stored information in the MN can be exchanged with another MN (MN2), see block 540. For example, MN1 may request via a message(s) another MN2 to report the T310 / 312 timer values and possibly also T310 / 312 threshold values if available for the cells, which may also act as PSCell for MN1. This or these messages may be dedicated for this purpose, such as using existing messages but with IE(s) introduced for this purpose or new messages for this purpose. This option is applicable for scenarios when MN2 (or MN1) has enough data stored, e.g., in a database, to be shared with another MN1 (or MN2).

[0148] In block 570, the MN, based on its stored information (e.g., in a database), filled either from direct UE reports or by information exchange with neighboring MNs, determines the settings for T310 / T312 threshold values.

[0149] 4. Additional details1

[0150] Further description of phase 1 is as follows and is illustrated in part by FIG. 6, which is a logic flow diagram of a first phase of SPR configuration and reporting for MN- initiated PSCell change and CPC.

[0151] In phase 1 , the content of SPR may be extended with two additional elements as indicated by references 520 and 530 (see block 610 for examples of possible content of the SPR):

[0152] 1) Source and target cell IDs of the PSCell change,

[0153] 2) Latest radio link measurements of all measurement IDs available at the time PSCell change is executed for all handover types (including CPC),

[0154] 3) A cause that was the trigger for generating the SPCR, i.e., t310-cause, t312- cause, t304-cause,

[0155] 4) Latest radio measurement results of the candidate target cells in case of conditional PSCell change (CPC),

[0156] 5) Time elapsed between CPC execution towards target cell and corresponding latest configuration received for the selected target cell,

[0157] 6) RA-InformationCommon when T304 is above a threshold,

[0158] 7) Available location information,

[0159] 8) CGI of PCell,

[0160] 9) Indication of whether PSCell change is MN-initiated or SN-initiated,

[0161] 10) T310 / 312 Timer thresholds of the source PSCell (reported for SN initiatedPSCell change) (520), and

[0162] 11) T310 / 312 Timer values of the source PSCell (reported both for MN andSN initiated PSCell change) (530).

[0163] As indicated, number (10) corresponds to block 520 from FIG. 5, and number (11) corresponds to block 530 from FIG. 5. Furthermore, in this example, reference 510 has been split into references 510-1, where the UE logs information in the SPR, and 510-2, where the UE delivers the SPR to the network.

[0164] Each SPR, regardless whether the SPR is related to MN- or SN-initiatedPSCell change, is retrieved by / forwarded to the source MN containing the PCell. See block 620.In block 630, the MN opens the SPR, and may obtain the information of the T310 / 312 timer values and in addition the T310 / 312 thresholds if the PSCell change is initiated by the SN. The MN may then internally store (e.g., in a database) the T310 / 312 threshold and timer values per each cell acting as source PSCell. See block 640. The longer the time the MN receives SPRs, for more PSCells, then typical T310 / 312 thresholds and timer values will be able to be determined. Then, as in block 650, for MN-initiated PSCell change or CPC, the MN may use the assistance information for the source PSCell if available and properly use this information for tuning the T310 / 312 thresholds and using the T310 / 312 timer values for proper optimization based on the SPR.

[0165] Phase 2 is now described in more detail. This involves a message exchange (see block 710, which is an example of block 540) between the MN (MN1) and another MN (e.g., MN2). MN1 may request, e.g., via dedicated message, another MN2 to report the T310 / 312 timer values and possibly also T310 / 312 threshold values if available for the cells which may also act as PSCell for the related MN1. See block 720. To implement this, messages could be defined to exchange such information on, e.g., an Xn interface. The exact name and form of the messages is for future study. The following is a proposal of the messages name and their content. In block 730, the “T310 / 312 timers and threshold Request” message is requested by the MN. FIG. 8 is an example of an IE 800 for a “T310 / 312 timers and threshold Request” message as in block 730. In block 740, the MN2 replies with a “T310 / 312 timers and threshold Answer” message. FIG. 9 is an example of an IE 900 for the “T310 / 312 timers and threshold Answer” as in block 740. In the example of FIG. 9, the lE / group name of T310 has a presence of mandatory (M) (instead of optional, O), meaning that it must be included, and the range has these possible enumerations: msO; ms50; mslOO; ms200; ms500; mslOOO; ms2000; ms4000; or ms6000. These are indications of millisecond (ms) values, and a zero value basically it means that once T310 started, it leads to an RLF declaration on UE side. Also, the lE / group name of T312 has a presence of mandatory (M) (instead of optional, O), and the range has these possible enumerations: msO; ms50; mslOO; ms300; ms400; ms500; or mslOOO. The thresholdPercentageT310 has a presence of optional, O, and has enumerated ranges of the following: p40; p60; p80. As described previously, these are percentages to indicate the ratio ofthe threshold value (unit: ms) over the signaled T310 / T312 / T304 value (unit: ms). The thresholdPercentageT312 has a presence of optional, O, and has enumerated ranges of the following: p20; p40; p60; p80.

[0166] The MN1 node may request, via the “T310 / 312 timers and threshold Request” message, e.g., with IE 800, another MN2 node to report T310 / 312 timer and threshold values for the list of cells acting as PSCells in the MN1 node (PSCell List). The MN2 node may report within the “T310 / 312 timers and threshold Answer” message, with, e.g., IE 900, the T310 / 312 timer and threshold values for the cells from the PSCell List requested by MN1 node, if available.

[0167] Block 750 is similar to block 570 of FIG. 5. In block 750, the MN, based on its stored information (e.g., in a database), filled either from direct UE reports or by information exchange with neighboring MNs from 710-740, determines the settings for T310 / T312 threshold values. In more detail, the MN, based on the assistant information in the form of timer values, may evaluate the threshold for SPR configuration. One idea is that the thresholds in the source PSCell may be set to lower value but also to a higher value. The MN, based on the known timer value, may decide the most appropriate timer threshold for SPR. Without knowledge of the timer values, the MN may just blindly decide on proper threshold timer values which prolongs the time need to properly tune the timer thresholds.

[0168] Phase 2 may be preferably used after the MN storage (e.g., database) is filled in with T310 / 312 timer and thresholds values per PSCell but also per UE (in case the T312 / 310 thresholds and timers are UE specific) in phase 1. The information from the MN database then can be shared in phase 2 to another MN.

[0169] One advantage of using this method, as opposed to MN blindly setting T310 / T312 thresholds, is that a better and more meaningful threshold can be set by MN based on the acquired information. This will also mean that the optimization algorithm (SON, AI / ML or any other algorithm) that is using the SPR will converge in less time to stable settings. Also, by forwarding the available information from one MN to another MN also decreases the amount of time and number of gathered SPRs needed for reaching a proper setting of the T310 / T312 thresholds across the network.

[0170] Turning to FIG. 10, this figure shows a block diagram of one possible and non-limiting example of a cellular network 1 that is connected to a user equipment (UE) 10. A number of network elements are shown in the cellular network 1 of FIG. 10: base stations 70 (including 70-1, 70-2, 70-3, and 70-4); and a core network 90.

[0171] In FIG. 10, a user equipment (UE) 10 is in wireless communication via radio link 11-1 with the base station 70-1 and via radio link 11-2 with the base station 70-2 of the cellular network 1. The base station (BS) 70-1 illustrates the MN, the BS 70-2 illustrates the S- SN, the BS 70-3 illustrates the T-Sn, the BS 70-4 illustrates the other T-SN, and there could be additional BSs that are not shown. The UE may also connect to BSs 70-3 and / or 70-4 via corresponding links 11, but these are not shown.

[0172] A UE 10 is a wireless communication device, such as a mobile device, that is configured to access a cellular network. The UE 10 is illustrated with one or more antennas 28. The ellipses 2 indicate there could be multiple UEs 10 in wireless communication via radio links with the base station 70. The UE 10 includes one or more processors 13, one or more memories 15, and other circuitry 16. The other circuitry 16 includes one or more receivers (Rx(s)) 17 and one or more transmitters (Tx(s)) 18. A program 12 is used to cause the UE 10 to perform the operations described herein. For a UE 10, the other circuitry 16 could include circuitry such as for user interface elements (not shown) like a display.

[0173] The base stations 70, as network nodes of the cellular network 1, provide the UE 10 access to cellular network 1 and to the data network 91 via the core network 90 (e.g., via a user plane function (UPF) of the core network 90). As such, the base station 70 may be considered to be a node of the cellular network 1, and in particular an access node, which provides access by UE(s) 10 to the cellular network 1. A single base station 70 is considered to be representative and is illustrated as having one or more antennas 58. In general, the base station 70 may be referred to as RAN node 70, although many will make reference to this as a gNB (gNode B, a base station for NR, new radio) instead. There are, however, many other examples of RAN nodes including an eNB (evolved Node B) or TRP (Transmission-Reception Point). The base station 70 includes one or more processors 73, one or more memories 75, and other circuitry 76. The other circuitry 76 includes one or more receivers (Rx(s)) 77 and one or more transmitters(Tx(s)) 78. A program 72 is used to cause the base station 70 to perform the operations described herein.

[0174] It is noted that the base station 70 may instead be implemented via other wireless technologies, such as 6G where the DC is likely to be re-used. Other technologies are possible too.

[0175] Two or more base stations 70 communicate using, e.g., link(s) 79. The link(s) 79 may be wired or wireless or both and may implement, e.g., an Xn interface for 5G (fifth generation), an X2 interface for LTE (Long Term Evolution), or other suitable interface for other standards.

[0176] The cellular network 1 may include a core network 90, as one network element or multiple network elements, that may include core network functionality, and which provide connectivity via a link or links 81 with a data network 91, such as a telephone network and / or a data communications network (e.g., the Internet). The core network 90 includes one or more processors 93, one or more memories 95, and other circuitry 96. The other circuitry 96 includes one or more receivers (Rx(s)) 97 and one or more transmitters (Tx(s)) 98. A program 92 is used to cause the core network 90 to perform the operations described herein.

[0177] The core network 90 could be a 5GC (5G core network). The core network 90 can implement or comprise multiple network functions (NF(s)) 99, and the program 92 may comprise one or more of the NFs 99. A 5G core network may use hardware such as memory and processors and a virtualization layer. It could be a single standalone computing system, a distributed computing system, or a cloud computing system. The NFs 99, as network elements, of the core network could be containers or virtual machines running on the hardware of the computing system(s) making up the core network 90.

[0178] Core network functionality for 5G may include access and mobility management functionality that is provided by a network function 99 such as an access and mobility management function (AMF), a user plane function (UPF), session management functionality that is provided by a network function such as a session management function (SMF). Core network functionality for access and mobility management in an LTE (Long Term Evolution) network may be provided by an MME (Mobility Management Entity) and / or SGW(Serving Gateway) functionality, which routes data to the data network. Many others are possible, as illustrated by the examples in FIG. 10: AMF; SMF; MME; SGW; GMLC (Gateway Mobile Location Center); LMF (Location Management Function); UDM (Unified Data Management) / UDR (Unified Data Repository); NRF (Network Repository Function); and / or E- SMLC (Evolved Serving Mobile Location Center). These are merely exemplary core network functionality that may be provided by the core network 90, and note that both 5G and LTE core network functionality might be provided by the core network 90. The base station 70 is coupled via a backhaul link 31 to the core network 90. The base station 70 and the core network 90 may include an NG (Next Generation) interface for 5G, or an SI interface for LTE, or other suitable interface for other radio access technologies for communicating via the backhaul link 31.

[0179] In the data network 91, there is a computer-readable medium 94. The computer-readable medium 94 contains instructions that, when downloaded and installed into the memories 15, 75, or 95 of the corresponding UE 10, base station 70, and / or core network 90 and corresponding element(s), and executed by processor(s) 13, 73, or 93, cause the respective device to perform corresponding actions described herein. The computer-readable medium 94 may be implemented in other forms, such as via a compact disc or memory stick.

[0180] The programs 12, 72, and 92 contain instructions stored by corresponding one or more memories 15, 75, or 95. These instructions, when executed by the corresponding one or more processors 13, 73, or 93, cause the corresponding apparatus 10, 70, or 90, to perform the operations described herein. The computer readable memories 15, 75, or 95 are circuitry and may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, flash memory, firmware, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. The computer readable memories 15, 75, and 95 may be means for performing storage functions. The processors 13, 73, and 93, are circuitry and may be of any type suitable to the local technical environment. For example, these processors may include one or more of general-purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs), processors based on a multi-core processor architecture, and may also include specialized circuits such as field-programmable gate arrays(FPGAs), application specific circuits (ASICs), signal processing devices and other devices, or combinations of these devices, as non-limiting examples. The processors 13, 73, and 93 may be means for causing their respective apparatus to perform functions, such as those described herein.

[0181] The receivers 17, 77, and 97, and the transmitters 18, 78, and 98 may implement wired or wireless interfaces. The receivers and transmitters may be grouped together as transceivers.

[0182] The cellular network 1 may implement network virtualization, which is the process of combining hardware and software network resources and network functionality into a single, software-based administrative 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 parts of networks, into a virtual unit, or internal, providing network-like functionality to software containers on a single system. Note that the virtualized entities (such as network functions 99) that result from the network virtualization are still implemented, at some level, using hardware such as processors 73 and / or 93 and memories 75 and / or 95, and also such virtualized entities create technical effects.

[0183] It is noted that description herein indicates that “cells” perform functions, but it should be clear that the base station that forms the cell will perform the functions. The cell makes up part of a base station. That is, there can be multiple cells per base station. For instance, there could be three cells for a single carrier frequency and associated bandwidth, each cell covering one-third of a 360-degree area so that the single base station’s coverage area covers an approximate oval or circle. Furthermore, each cell can correspond to a single carrier and a base station may use multiple carriers. So, if there are three 120-degree cells per carrier and two carriers, then the base station has a total of six cells.

[0184] In general, the various embodiments of the user equipment 10 can include, but are not limited to, cellular telephones (such as smart phones, mobile phones, cellular phones, voice over Internet Protocol (IP) (VoIP) phones, and / or wireless local loop phones), tablets, portable computers, vehicles or vehicle-mounted devices for, e.g., wireless V2X (vehicle-to- everything) communication, image capture devices such as digital cameras, gaming devices,music storage and playback appliances, Internet appliances (including Internet of Things, loT, devices), loT devices with sensors and / or actuators for, e.g., automation applications, as well as portable units or terminals that incorporate combinations of such functions, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), Universal Serial Bus (USB) dongles, smart devices, wireless customer-premises equipment (CPE), an Internet of Things (loT) device, a watch or other wearable, a head-mounted display (HMD), a vehicle, a drone, a medical device and applications (e.g., remote surgery), an industrial device and applications (e.g., a robot and / or other wireless devices operating in an industrial and / or an automated processing chain contexts), a consumer electronics device, a device operating on commercial and / or industrial wireless networks, and the like. That is, the UE 10 could be any end device that may be capable of wireless communication. By way of example rather than limitation, the UE may also be referred to as a communication device, terminal device (MT), a Subscriber Station (SS), a Portable Subscriber Station, a Mobile Station (MS), or an Access Terminal (AT).

[0185] Without in any way limiting the scope, interpretation, or application of the claims appearing below, a technical effect and / or advantage of one or more of the example embodiments disclosed herein is it makes it feasible for the MN to configure the proper T310 / 312 thresholds for MN initiated PSCell change. Another technical effect and / or advantage of one or more of the example embodiments disclosed herein is related to previous point, where the method is performing the techniques without any additional information exchange between source SN and MN, but re-uses the SPR which, with added new assistance informationT310 / 312 timer / thresholds for SN initiated PSCell change), is already reported in case T310 / 312 triggering criteria are met, which is based on building an internal store such as a database in the MN. Another technical effect and / or advantage of one or more of the example embodiments disclosed herein is related to previous point where the database info may be shared with another MN. Another technical effect and / or advantage of one or more of the example embodiments disclosed herein applies to the overall scenario, where the method makes it feasible for the MN to configure the proper T310 / 312 thresholds for MN-initiated PSCell change without any extra information exchange on the Xn interface.

[0186] The following are additional examples.

[0187] Example 1. A method, comprising: determining, by a user equipment connected towards at least one cellular network via a primary cell provided by a master node and a primary secondary cell provided by a secondary node, information related to at least one value of at least one timer associated with a connection status of the user equipment towards the primary secondary cell; generating, by the user equipment, in case of a primary secondary cell change procedure, a related successful primary secondary cell change report including at least one configured timer value associated with the primary secondary cell based at least on the information; and sending, by the user equipment towards a node of the at least one cellular network, the generated successful primary secondary cell change report including the at least one configured timer value associated with the primary secondary cell.

[0188] Example 2. The method according to example 1, wherein one of the at least one configured timer value comprises a configured timer value used for timer T310.

[0189] Example 3. The method according to example 2, wherein the configured timer value used for timer T310 is indicated in the generated successful primary secondary cell change report using a range in milliseconds selected from a plurality of range values.

[0190] Example 4. The method according to any of examples 1 to 3, wherein one of the at least one configured timer value comprises a configured timer value used for timer T312 in case of secondary node-initiated primary secondary cell changes.

[0191] Example 5. The method according to example 4, wherein the configured timer value used for timer T312 is indicated in the generated successful primary secondary cell change report using a range in milliseconds selected from a plurality of range values.

[0192] Example 6. The method according to either example 3 or 5, wherein presence of the configured timer value used for a corresponding timer is mandatory in the generated successful primary secondary cell change report.

[0193] Example 7. The method according to any of examples 1 to 6, wherein the information further comprises a timer threshold for a corresponding one of the at least one configured timer value associated with the primary secondary cell.

[0194] Example 8. The method according to example 7, wherein the generated successful primary secondary cell change report further comprises a timer threshold generated using the information, expressed as a percentage, and used for timer T310.

[0195] Example 9. The method according to any of examples 7 or 8, wherein the generated successful primary secondary cell change report further comprises a timer threshold generated using the information, expressed as a percentage, and used for timer T312.

[0196] Example 10. A method, comprising: receiving, by a node that provides a primary cell as a master node to a user equipment in at least one cellular network, a successful primary secondary cell change report including at least one configured timer value associated with a primary secondary cell, wherein a secondary node provides the primary secondary cell to the user equipment; and storing, by the node, information comprising the at least one configured timer value associated with the primary secondary cell.

[0197] Example 11. The method according to example 10, further comprising: using, by the node for master node-initiated primary secondary cell change or conditional primary secondary cell change, the stored information for a source primary secondary cell.

[0198] Example 12. The method according to any of examples 10 or 11, further comprising: using, by the node, the stored information for tuning the at least one configured timer value associated with the primary secondary cell and using the at least one configured timer value associated with the primary secondary cell for optimization via the tuning based on the stored information.

[0199] Example 13. The method according to any of examples 10 to 30, further comprising: exchanging, by the node, the stored information in the node with another node in the at least one cellular network.

[0200] Example 14. The method according to example 13, wherein the exchanging comprises requesting, via a message by the node to the other node, to report one or more timer values, and receiving by the node the one or more timer values from the other node.

[0201] Example 15. The method according to example 14, wherein the exchanging comprises requesting, via a message by the node to the other node, to report one or morethreshold values, and receiving by the node the one or more threshold values from the other node.

[0202] Example 16. A computer program, comprising instructions for performing the methods of any of examples 1 to 15, when the computer program is run on an apparatus.

[0203] Example 17. The computer program according to example 16, wherein the computer program is a computer program product comprising a computer-readable medium bearing instructions embodied therein for use with the apparatus.

[0204] Example 18. The computer program according to example 16, wherein the computer program is directly loadable into an internal memory of the apparatus.

[0205] Example 19. An apparatus, comprising means for performing: determining, by a user equipment connected towards at least one cellular network via a primary cell provided by a master node and a primary secondary cell provided by a secondary node, information related to at least one value of at least one timer associated with a connection status of the user equipment towards the primary secondary cell; generating, by the user equipment, in case of a primary secondary cell change procedure, a related successful primary secondary cell change report including at least one configured timer value associated with the primary secondary cell based at least on the information; and sending, by the user equipment towards a node of the at least one cellular network, the generated successful primary secondary cell change report including the at least one configured timer value associated with the primary secondary cell.

[0206] Example 20. The apparatus according to example 19, wherein one of the at least one configured timer value comprises a configured timer value used for timer T310.

[0207] Example 21. The apparatus according to example 20, wherein the configured timer value used for timer T310 is indicated in the generated successful primary secondary cell change report using a range in milliseconds selected from a plurality of range values.

[0208] Example 22. The apparatus according to any of examples 19 to 21, wherein one of the at least one configured timer value comprises a configured timer value used for timer T312 in case of secondary node-initiated primary secondary cell changes.

[0209] Example 23. The apparatus according to example 22, wherein the configured timer value used for timer T312 is indicated in the generated successful primary secondary cell change report using a range in milliseconds selected from a plurality of range values.

[0210] Example 24. The apparatus according to either example 21 or 23, wherein presence of the configured timer value used for a corresponding timer is mandatory in the generated successful primary secondary cell change report.

[0211] Example 25. The apparatus according to any of examples 19 to 24, wherein the information further comprises a timer threshold for a corresponding one of the at least one configured timer value associated with the primary secondary cell.

[0212] Example 26. The apparatus according to example 25, wherein the generated successful primary secondary cell change report further comprises a timer threshold generated using the information, expressed as a percentage, and used for timer T310.

[0213] Example 27. The apparatus according to any of examples 25 or 26, wherein the generated successful primary secondary cell change report further comprises a timer threshold generated using the information, expressed as a percentage, and used for timer T312.

[0214] Example 28. An apparatus, comprising means for performing: receiving, by a node that provides a primary cell as a master node to a user equipment in at least one cellular network, a successful primary secondary cell change report including at least one configured timer value associated with a primary secondary cell, wherein a secondary node provides the primary secondary cell to the user equipment; and storing, by the node, information comprising the at least one configured timer value associated with the primary secondary cell.

[0215] Example 29. The apparatus according to example 28, wherein the means are further configured for performing: using, by the node for master node-initiated primary secondary cell change or conditional primary secondary cell change, the stored information for a source primary secondary cell.

[0216] Example 30. The apparatus according to any of examples 28 to 29, wherein the means are further configured for performing: using, by the node, the stored information for tuning the at least one configured timer value associated with the primary secondary cell andusing the at least one configured timer value associated with the primary secondary cell for optimization via the tuning based on the stored information.

[0217] Example 31. The apparatus according to any of examples 28 to 30, wherein the means are further configured for performing: exchanging, by the node, the stored information in the node with another node in the at least one cellular network.

[0218] Example 32. The apparatus according to example 31, wherein the exchanging comprises requesting, via a message by the node to the other node, to report one or more timer values, and receiving by the node the one or more timer values from the other node.

[0219] Example 33. The apparatus according to example 32, wherein the exchanging comprises requesting, via a message by the node to the other node, to report one or more threshold values, and receiving by the node the one or more threshold values from the other node.

[0220] Example 34. The apparatus of any preceding apparatus example, wherein the means comprises: at least one processor; and at least one memory storing instructions that, when executed by at least one processor, cause the performance of the apparatus.

[0221] Example 35. An apparatus, comprising: one or more processors; and one or more memories storing instructions that, when executed by the one or more processors, cause the apparatus at least to perform: determining, by a user equipment connected towards at least one cellular network via a primary cell provided by a master node and a primary secondary cell provided by a secondary node, information related to at least one value of at least one timer associated with a connection status of the user equipment towards the primary secondary cell; generating, by the user equipment, in case of a primary secondary cell change procedure, a related successful primary secondary cell change report including at least one configured timer value associated with the primary secondary cell based at least on the information; and sending, by the user equipment towards a node of the at least one cellular network, the generated successful primary secondary cell change report including the at least one configured timer value associated with the primary secondary cell.

[0222] Example 36. The apparatus according to example 35, wherein one of the at least one configured timer value comprises a configured timer value used for timer T310.

[0223] Example 37. The apparatus according to example 36, wherein the configured timer value used for timer T310 is indicated in the generated successful primary secondary cell change report using a range in milliseconds selected from a plurality of range values.

[0224] Example 38. The apparatus according to any of examples 35 to 37, wherein one of the at least one configured timer value comprises a configured timer value used for timer T312 in case of secondary node-initiated primary secondary cell changes.

[0225] Example 39. The apparatus according to example 38, wherein the configured timer value used for timer T312 is indicated in the generated successful primary secondary cell change report using a range in milliseconds selected from a plurality of range values.

[0226] Example 40. The apparatus according to either example 37 or 39, wherein presence of the configured timer value used for a corresponding timer is mandatory in the generated successful primary secondary cell change report.

[0227] Example 41. The apparatus according to any of examples 35 to 40, wherein the information further comprises a timer threshold for a corresponding one of the at least one configured timer value associated with the primary secondary cell.

[0228] Example 42. The apparatus according to example 41, wherein the generated successful primary secondary cell change report further comprises a timer threshold generated using the information, expressed as a percentage, and used for timer T310.

[0229] Example 43. The apparatus according to any of examples 42 or 43, wherein the generated successful primary secondary cell change report further comprises a timer threshold generated using the information, expressed as a percentage, and used for timer T312.

[0230] Example 44. An apparatus, comprising: one or more processors; and one or more memories storing instructions that, when executed by the one or more processors, cause the apparatus at least to perform: receiving, by a node that provides a primary cell as a master node to a user equipment in at least one cellular network, a successful primary secondary cell change report including at least one configured timer value associated with a primary secondary cell, wherein a secondary node provides the primary secondary cell to the user equipment; and storing, by the node, information comprising the at least one configured timer value associated with the primary secondary cell.

[0231] Example 45. The apparatus according to example 44, wherein the one or more memories further store instructions that, when executed by the one or more processors, cause the apparatus at least to perform: using, by the node for master node-initiated primary secondary cell change or conditional primary secondary cell change, the stored information for a source primary secondary cell.

[0232] Example 46. The apparatus according to any of examples 44 or 45, wherein the one or more memories further store instructions that, when executed by the one or more processors, cause the apparatus at least to perform: using, by the node, the stored information for tuning the at least one configured timer value associated with the primary secondary cell and using the at least one configured timer value associated with the primary secondary cell for optimization via the tuning based on the stored information.

[0233] Example 47. The apparatus according to any of examples 44 to 46, wherein the one or more memories further store instructions that, when executed by the one or more processors, cause the apparatus at least to perform: exchanging, by the node, the stored information in the node with another node in the at least one cellular network.

[0234] Example 48. The apparatus according to example 47, wherein the exchanging comprises requesting, via a message by the node to the other node, to report one or more timer values, and receiving by the node the one or more timer values from the other node.

[0235] Example 49. The apparatus according to example 48, wherein the exchanging comprises requesting, via a message by the node to the other node, to report one or more threshold values, and receiving by the node the one or more threshold values from the other node.

[0236] As used in this application, the term “circuitry” may refer to one or more or all of the following:

[0237] (a) hardware-only circuit implementations (such as implementations in only analog and / or digital circuitry) and

[0238] (b) combinations of hardware circuits and software, such as (as applicable): (i) a combination of analog and / or digital hardware circuit(s) with software / firmware and (ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software,and memory(ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and

[0239] (c) hardware circuit(s) and or processor(s), such as a microprocessor(s) or a portion of a microprocessor(s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.

[0240] This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and / or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device.

[0241] Embodiments herein may be implemented in software (executed by one or more processors), hardware (e.g., an application specific integrated circuit), or a combination of software and hardware. In an example embodiment, the software (e.g., application logic, an instruction set) is maintained on any one of various conventional computer-readable media. In the context of this document, a “computer-readable medium” may be any media or means that can contain, store, communicate, propagate or transport the instructions for use by or in connection with an instruction execution system, apparatus, or device, such as a computer, with one example of a computer described and depicted, e.g., in FIG. 10. A computer-readable medium may comprise a computer-readable storage medium (e.g., memories 15, 75, and 95 or other device) that may be any media or means that can contain, store, and / or transport the instructions for use by or in connection with an instruction execution system, apparatus, or device, such as a computer. A computer-readable storage medium does not comprise propagating signals, and therefore may be considered to be non-transitory. The term “non-transitory”, as used herein, is a limitation of the medium itself (i.e., tangible, not a signal) as opposed to a limitation on data storage persistency (e.g., RAM, random access memory, versus ROM, readonly memory).

[0242] If desired, the different functions discussed herein may be performed in a different order and / or concurrently with each other. Furthermore, if desired, one or more of the above-described functions may be optional or may be combined.

[0243] Although various aspects of the invention are set out in the independent claims, other aspects of the invention comprise other combinations of features from the described embodiments and / or the dependent claims with the features of the independent claims, and not solely the combinations explicitly set out in the claims.

[0244] It is also noted herein that while the above describes example embodiments of the invention, these descriptions should not be viewed in a limiting sense. Rather, there are several variations and modifications which may be made without departing from the scope of the present invention as defined in the appended claims.

[0245] The following abbreviations that may be found in the specification and / or the drawing figures are defined as follows:

[0246] 5G fifth generation

[0247] a.k.a also known as

[0248] Al Artificial Intelligence

[0249] AM Acknowledge Mode

[0250] AMF access and mobility management function

[0251] BS base station

[0252] CGI cell global identity

[0253] CPAC Conditional primary secondary cell (PSCell) addition and change

[0254] CPC Conditional PSCell Change

[0255] DC Dual Connectivity

[0256] DL downlink

[0257] E-SMLC evolved serving mobile location center

[0258] GMLC Gateway Mobile Location Center

[0259] eNB (or eNodeB) evolved Node B (e.g., an LTE base station)

[0260] gNB (or gNodeB) base station for 5G / NR

[0261] ID identification

[0262] IE information element

[0263] I / F interface

[0264] LMF Location Management Function

[0265] LIE long term evolution

[0266] MCG Master Cell Group

[0267] ML Machine Learning

[0268] MME mobility management entity

[0269] MN Master node

[0270] NF network function

[0271] ng or NG next generation

[0272] NR new radio

[0273] NRF Network Repository Function

[0274] N / W or NW network

[0275] PDCP packet data convergence protocol

[0276] PSCell primary secondary cell

[0277] QoS quality of service

[0278] RAN radio access network

[0279] RAT radio access technology

[0280] Rx receiver

[0281] SCG Secondary Cell Group

[0282] SCell secondary cell

[0283] SDU service data unit

[0284] SGW serving gateway

[0285] SIB system information block

[0286] SPCR another acronym for SPR

[0287] SPR Successful PSCell Change Report

[0288] SMF session management function

[0289] SN Secondary node

[0290] S-SN source SN

[0291] TNL transport network layer

[0292] T-SN target SN

[0293] TRP transmission-reception point

[0294] Tx transmitter

[0295] UDM unified data management

[0296] UDR unified data repository

[0297] UE user equipment (e.g., a wireless, typically mobile device)

[0298] UPF user plane function

[0299] Xn interface between the two NG RAN nodes

Claims

What is claimed is:

1. An apparatus, comprising means for performing: determining, by a user equipment connected towards at least one cellular network via a primary cell provided by a master node and a primary secondary cell provided by a secondary node, information related to at least one value of at least one timer associated with a connection status of the user equipment towards the primary secondary cell; generating, by the user equipment, in case of a primary secondary cell change procedure, a related successful primary secondary cell change report including at least one configured timer value associated with the primary secondary cell based at least on the information; and sending, by the user equipment towards a node of the at least one cellular network, the generated successful primary secondary cell change report including the at least one configured timer value associated with the primary secondary cell.

2. The apparatus according to claim 1, wherein one of the at least one configured timer value comprises a configured timer value used for timer T310.

3. The apparatus according to claim 2, wherein the configured timer value used for timer T310 is indicated in the generated successful primary secondary cell change report using a range in milliseconds selected from a plurality of range values.

4. The apparatus according to any of claims 1 to 3, wherein one of the at least one configured timer value comprises a configured timer value used for timer T312 in case of secondary node-initiated primary secondary cell changes.

5. The apparatus according to claim 4, wherein the configured timer value used for timer T312 is indicated in the generated successful primary secondary cell change report using a range in milliseconds selected from a plurality of range values.

6. The apparatus according to either claim 3 or 5, wherein presence of the configured timer value used for a corresponding timer is mandatory in the generated successful primary secondary cell change report.

7. The apparatus according to any of claims 1 to 6, wherein the information further comprises a timer threshold for a corresponding one of the at least one configured timer value associated with the primary secondary cell.

8. The apparatus according to claim 7, wherein the generated successful primary secondary cell change report further comprises a timer threshold generated using the information, expressed as a percentage, and used for timer T310.

9. The apparatus according to any of claims 7 or 8, wherein the generated successful primary secondary cell change report further comprises a timer threshold generated using the information, expressed as a percentage, and used for timer T312.

10. An apparatus, comprising means for performing: receiving, by a node that provides a primary cell as a master node to a user equipment in at least one cellular network, a successful primary secondary cell change report including at least one configured timer value associated with a primary secondary cell, wherein a secondary node provides the primary secondary cell to the user equipment; and storing, by the node, information comprising the at least one configured timer value associated with the primary secondary cell.

11. The apparatus according to claim 10, wherein the means are further configured for performing: using, by the node for master node-initiated primary secondary cell change or conditional primary secondary cell change, the stored information for a source primary secondary cell.

12. The apparatus according to any of claims 10 to 11, wherein the means are further configured for performing: using, by the node, the stored information for tuning the at least one configured timer value associated with the primary secondary cell and using the at least one configured timer value associated with the primary secondary cell for optimization via the tuning based on the stored information.

13. The apparatus according to any of claims 10 to 12, wherein the means are further configured for performing: exchanging, by the node, the stored information in the node with another node in the at least one cellular network.

14. The apparatus according to claim 13, wherein the exchanging comprises requesting, via a message by the node to the other node, to report one or more timer values, and receiving by the node the one or more timer values from the other node.

15. The apparatus according to claim 14, wherein the exchanging comprises requesting, via a message by the node to the other node, to report one or more threshold values, and receiving by the node the one or more threshold values from the other node.

16. The apparatus of any preceding apparatus claim, wherein the means comprises: at least one processor; andat least one memory storing instructions that, when executed by at least one processor, cause the performance of the apparatus.

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