Apparatus for use in an access node

Abstract

The present application relates to an apparatus for use in an access node (AN) that serves as a master node (MN) connected to a secondary node (SN) over an X2 or Xn interface in a long term evolution-dual connectivity (LTE-DC) or multi-radio access technology-dual connectivity (MR-DC) scenario, the AN comprising processor circuitry configured to cause the AN, during a conditional handover (CHO) procedure of a user equipment (UE): to send a plurality of data forwarding address indication messages to the SN, wherein each data forwarding address indication message of the plurality of data forwarding address indication messages contains a data forwarding address corresponding to a candidate target AN; and for each data forwarding address indication message of the plurality of data forwarding address indication messages, to receive an early status transfer message or a failure report message sent by the SN in response to the data forwarding address indication message.

Description

[0001] Priority requirements

[0002] This application is based on and claims priority to U.S. Patent Application No. 63 / 135,939, filed January 11, 2021, which is incorporated herein by reference in its entirety. Technical Field

[0003] Embodiments of this disclosure generally relate to the field of wireless communication, and more particularly to an apparatus used in an access node (AN). Background Technology

[0004] Mobile communication has evolved from early voice systems to today's highly complex integrated communication platforms. 5G, or New Radio (NR) wireless communication systems, will provide various users and applications with access to information and data sharing anytime, anywhere, and will coexist with 4G or Long Term Evolution (LTE) wireless communication systems for a long time. Attached Figure Description

[0005] Embodiments of this disclosure will be illustrated in the accompanying drawings by way of example rather than limitation, wherein similar reference numerals refer to similar elements.

[0006] Figure 1 An example signaling flow is shown for the MN to ng-eNB / gNB changeover process in an MR-DC scenario with 5GC.

[0007] Figure 2A A flowchart of a method used in an access node (AN) according to some embodiments of the present disclosure is shown, wherein the AN is used as an MN connected to the SN via an X2 or Xn interface in an LTE-DC or MR-DC scenario.

[0008] Figure 2B A flowchart of a method used in an access node (AN) according to some embodiments of the present disclosure is shown, wherein the AN is used as a SN connected to the MN via an X2 or Xn interface in an LTE-DC or MR-DC scenario.

[0009] Figure 3 An example signaling flow is shown for the MN to eNB changeover process in an MR-DC scenario with EPC.

[0010] Figure 4 An example signaling flow for the MeNB to eNB transition process in an LTE-DC scenario is shown.

[0011] Figure 5 An example signaling flow is shown for the MN to ng-eNB / gNB changeover process in an MR-DC scenario with 5GC.

[0012] Figure 6 A schematic diagram of a network according to various embodiments of the present disclosure is shown.

[0013] Figure 7 A schematic diagram of a wireless network according to various embodiments of the present disclosure is shown.

[0014] Figure 8 A block diagram is shown of components according to some example embodiments of the present disclosure that are capable of reading instructions from a machine-readable or computer-readable medium (e.g., a non-transitory machine-readable storage medium) and performing any one or more methods discussed herein. Detailed Implementation

[0015] Various aspects of the illustrative embodiments will be described using terminology commonly used by those skilled in the art to convey the essence of this disclosure to others skilled in the art. However, it will be apparent to those skilled in the art that many alternative embodiments can be implemented using portions of the described aspects. Specific figures, materials, and configurations are given for illustrative purposes to provide a thorough understanding of the illustrative embodiments. However, it will be apparent to those skilled in the art that alternative embodiments can be implemented without these specific details. In other instances, well-known features may be omitted or simplified to avoid obscuring the illustrative embodiments.

[0016] Furthermore, the various operations are described sequentially as a plurality of discrete operations in a manner most conducive to understanding the illustrative embodiments; however, the order of description should not be construed as implying that these operations are necessarily sequentially related. In particular, these operations do not need to be performed in the order presented.

[0017] The phrases “in an embodiment,” “in one embodiment,” and “in some embodiments” are used repeatedly throughout this document. These phrases do not generally refer to the same embodiment; however, they may refer to the same embodiment. Unless the context otherwise requires, the terms “comprising,” “having,” and “including” are synonyms. The phrases “A or B” and “A / B” mean “(A), (B), or (A and B).”

[0018] In dual-connectivity (DC) scenarios, including LTE dual-connectivity (LTE-DC) and multi-radio access technology dual-connectivity (MR-DC) scenarios, conditional handover (CHO) of user equipment (UE) can be supported. For example, in an MR-DC scenario with a 5G core (5GC), when a UE conditionally switches from the source primary node (S-MN) to the target next-generation evolved Node B (ng-eNB) / next-generation node B (gNB), the MN to ng-eNB / gNB change procedure can be used to transfer the UE context data from the S-MN to the target ng-eNB / gNB. Here, the S-MN and the target ng-eNB / gNB can belong to the same radio access technology (i.e., they are both ng-eNBs or both gNBs) or different radio access technologies.

[0019] Figure 1 An example signaling flow is shown for the MN to ng-eNB / gNB changeover process in an MR-DC scenario with 5GC. (Example signaling flow follows.) Figure 1 As shown, the process of changing from MN to ng-eNB / gNB includes:

[0020] S102, S-MN sends a handover request message to the target ng-eNB / gNB to initiate the Xn handover preparation process.

[0021] Note 1: Before step S102, S-MN can trigger the MN-initiated secondary node (SN) modification process to retrieve the secondary cell group (SCG) configuration of the source secondary node (S-SN) and allow the provision of data forwarding related information to the S-SN.

[0022] S104, the target ng-eNB / gNB sends a handover request confirmation message to the S-MN, wherein the handover request confirmation message includes a field indicating the release of the SCG configuration of the S-SN. If it is necessary to perform early data forwarding for the SN-terminated bearer, the target ng-eNB / gNB can also provide a data forwarding address to the S-MN via the handover request confirmation message (i.e., the data forwarding address corresponding to the target ng-eNB / gNB can be included in the handover request confirmation message).

[0023] S106a, if the resource allocation of the target ng-eNB / gNB is successful, the S-MN sends an SN release request message to the S-SN, wherein the SN release request message includes the reason for indicating the mobility of the primary cell group (MCG).

[0024] S106b, the S-SN sends an SN release request confirmation message to the S-MN. Receiving the SN release request message triggers the S-SN to stop providing user data to the UE, and, if applicable, to begin normal data forwarding to the target ng-eNB / gNB.

[0025] S106c, if it is necessary to perform early data forwarding for the bearer terminated by the SN, the S-MN sends an Xn-U address indication message to the S-SN, wherein the Xn-U address indication message contains the data forwarding address corresponding to the target ng-eNB / gNB.

[0026] • Note 1a: In the case of UE's CHO, after S-MN receives an indication that UE has successfully accessed the target ng-eNB / gNB (i.e., after step S112), steps S106a and S106b are executed.

[0027] Note 1b: In the case of a UE's CHO, step S106c is executed immediately after step S104. The Xn-U address indication message is used by the S-MN to notify the S-SN of the UE's CHO and provide the S-SN with the data forwarding address corresponding to the target ng-eNB / gNB. The S-SN can then perform early data forwarding for the bearer terminated by the SN towards the data forwarding address corresponding to the target ng-eNB / gNB and send an early state transition message to the S-MN. If applicable, once the S-MN receives the SN release request message, the S-SN can perform normal data forwarding towards the target ng-eNB / gNB and send an SN state transition message to the S-MN. If the Xn-U address indication message is rejected by the S-SN, the S-MN can retransmit the message after step S106b.

[0028] When the S-MN decides to execute the UE's CHO, it does not immediately release the S-SN's SCG configuration after the CHO is prepared. Instead, the S-MN sends an Xn-U address indication message to the S-SN to provide the data forwarding address corresponding to the target ng-eNB / gNB, and notifies the S-SN of the UE's CHO so that the S-SN can execute early data forwarding for bearers terminated by the SN. If early data forwarding for bearers terminated by the SN is executed, the S-SN sends an extremely early state transition message to the S-MN.

[0029] In principle, the S-MN can prepare multiple candidate target nodes for the UE's CHO (e.g., candidate cell 1 with target gNB 1 and candidate cell 2 with target gNB 2), and the data forwarding addresses for different target nodes will be different. However, currently, the S-MN cannot provide these different data forwarding addresses to the S-SN. Only one Xn-U address indication message is allowed for advance data forwarding from the S-SN, which effectively restricts advance data forwarding to only one of the multiple candidate target nodes. This restriction essentially only supports advance data forwarding to a single candidate target node, or delayed data forwarding to other candidate target nodes besides that single candidate target node.

[0030] Additionally, when a UE's CHO is modified or canceled, any advance data forwarding initiated for bearers terminated by all or some SNs should also be canceled accordingly. However, currently in both LTE-DC and MR-DC scenarios, it is impossible to cancel advance data forwarding initiated for any SN-terminated bearer because the S-MN simply outputs the data forwarding address for advance data forwarding of bearers terminated by the SN via the XnAP Xn-U address indication message for the MR-DC scenario or the X2AP data forwarding address indication message for the LTE-DC scenario.

[0031] Therefore, this disclosure proposes a solution to overcome the above limitations and / or to cancel early data forwarding initiated for certain SN-terminated bearers in the event that the UE's CHO is modified or canceled.

[0032] Figure 2A A flowchart of a method 200A used in an access node (AN) according to some embodiments of the present disclosure is shown, wherein the AN serves as an MN connected to the SN via an X2 or Xn interface in an LTE-DC or MR-DC scenario. Figure 2A As shown, method 200A includes: S202A, during the CHO process of the UE, sending a plurality of data forwarding address indication messages to the SN, wherein each of the plurality of data forwarding address indication messages contains a data forwarding address corresponding to a candidate target AN; S204A, for each of the plurality of data forwarding address indication messages, receiving an early state transition message or a fault report message sent by the SN in response to the data forwarding address indication message.

[0033] Figure 2B A flowchart of method 200B for use in an access node (AN) according to some embodiments of the present disclosure is shown. This AN serves as a SN connected to an MN via an X2 or Xn interface in an LTE-DC or MR-DC scenario. Figure 2BAs shown, method 200B includes: S202B, during the UE's CHO procedure, receiving multiple data forwarding address indication messages from the MN, wherein each of the multiple data forwarding address indication messages contains a data forwarding address corresponding to a candidate target AN; S204B, for each of the multiple data forwarding address indication messages, when early data forwarding for a bearer terminated by the SN is performed toward the data forwarding address contained in the data forwarding address indication message, sending an early state transition message to the MN; S206B, for each of the multiple data forwarding address indication messages, when no early data forwarding for a bearer terminated by the SN is performed toward the data forwarding address contained in the data forwarding address indication message, sending a failure report message to the MN.

[0034] The aforementioned limitations can be mitigated by methods 200A and / or 200B through multiple operations that allow the transmission of data forwarding address indication messages and very early state transition messages between the MN and SN for different candidate target nodes.

[0035] In some embodiments, the data forwarding address indication message may also include a source identifier that uniquely identifies the association between the UE and the MN and a target identifier that uniquely identifies the association between the UE and the candidate target AN, and the very early state transition message may also include a source identifier that uniquely identifies the association between the UE and the MN and a target identifier that uniquely identifies the association between the UE and the candidate target AN.

[0036] In some embodiments, the data forwarding address indication message may further include an early data forwarding stop indication to indicate to the SN whether to stop early data forwarding initiated for bearers terminated by certain SNs. In this case, method 200B may further include: stopping early data forwarding initiated for bearers terminated by certain SNs when the early data forwarding stop indication indicates to stop early data forwarding initiated for bearers terminated by certain SNs.

[0037] The implementation of methods 200A and 200B in LTE-DC and MR-DC scenarios will be described below.

[0038] Methods 200A and 200B in LTE-DC scenarios or MR-DC scenarios with Evolved Packet Core (EPC) accomplish

[0039] In LTE-DC scenarios or MR-DC scenarios with EPC, multiple data forwarding address indication messages can be implemented as DATA FORWARDING ADDRESS INDICATION messages. The source identifier can include at least one of the source eNB UE X2AP identifier (ID) and the source eNB UE X2AP ID extension, and the target identifier can include at least one of the target eNB UE X2AP ID and the target eNB UE X2AP ID extension.

[0040] In LTE-DC scenarios or MR-DC scenarios with EPC, the DATA FORWARDINGADDRESS INDICATION message is used during the UE's CHO to provide the data forwarding address corresponding to different candidate target ANs to the source auxiliary eNB / en-gNB (S-SeNB / en-gNB).

[0041] In LTE-DC scenarios or MR-DC scenarios with EPC, the count (COUNT) value related to the downlink serving data unit (SDU) is transferred and forwarded from the S-SeNB / en-gNB to the source master eNB (S-MeNB) using the very early state transition message during the UE's CHO period.

[0042] The contents of the DATA FORWARDING ADDRESS INDICATION message and the very early state transition message are shown in Table 1-2.

[0043] Table 1-DATA FORWARDING ADDRESS INDICATION

[0044]

[0045] maxnoofBearers The maximum number value for E-RAB is 256.

[0046]

[0047] Table 2 - Very Early State Transitions

[0048]

[0049]

[0050] maxnoofBearers The maximum number value for E-RAB is 256.

[0051] Figure 3 An example signaling flow for the MN to eNB changeover procedure in an MR-DC scenario with EPC is shown. The MN to eNB changeover procedure can be used to transfer UE context data from the S-MN / SN to the target eNB. The MN to eNB changeover procedure includes:

[0052] S302, the S-MN sends a handover request message to the target eNB to initiate the X2 handover preparation process. The handover request message may include both the S-SN's SCG configuration and the S-MN's MCG configuration.

[0053] Note 1: Before step S302, S-MN can trigger the SN modification process initiated by MN to retrieve the SCG configuration of S-SN.

[0054] S304, the target eNB sends a handover request confirmation message to the S-MN. The handover request confirmation message may include a field indicating the release of the SCG configuration of the S-SN, and may also include the data forwarding address corresponding to the target eNB if it is necessary to perform early data forwarding for the bearer terminated by the SN.

[0055] S306a, if the resource allocation of the target eNB is successful, the S-MN sends an SgNB release request message to the S-SN, wherein the SgNB release request message may include a reason indicating the mobility of the MCG.

[0056] S306b, the S-SN sends an SgNB release request confirmation message to the S-MN. Receiving the SgNB release request message triggers the S-SN to stop providing user data to the UE, and, if applicable, to begin normal data forwarding.

[0057] • Note 1a: In the case of UE's CHO, after S-MN receives an indication that UE has successfully accessed the target eNB (i.e., after step S312), steps S306a and S306b are executed.

[0058] Note 1b: In the case of a UE's CHO, if early data forwarding of a bearer terminated by the SN is required, multiple data forwarding address indication messages can be sent from the S-MN to the S-SN immediately after step S304. The data forwarding address indication message is used to notify the S-SN of the UE's CHO and provide the S-SN with data forwarding addresses corresponding to different candidate target ANs. The S-SN can then perform early data forwarding for the bearer terminated by the SN towards the data forwarding addresses corresponding to the different candidate target ANs and send an early state transition message to the S-MN. Source / target UE X2AP ID pairs can be included in each data forwarding address indication message, and these data forwarding address indication messages can be identified by the source / target UE X2AP ID pairs in the multiple data forwarding address indication messages. Source / target UE X2AP ID pairs can also be included in each early state transition message, and these early state transition messages can be identified by the source / target UE X2AP ID pairs in the early state transition messages sent in response to the multiple data forwarding address indication messages. Based on the source / destination UE X2AP ID pair contained in the data forwarding address indication message and the early state transition message, the correspondence between the data forwarding address indication message and the early state transition message can be determined. The data forwarding address indication message may also contain an early data forwarding stop indication to instruct the S-SN to stop early data forwarding already initiated for some SN-terminated bearers (if they no longer require early data forwarding due to modification or cancellation of the UE's CHO). If applicable, once the S-SN receives the SgNB release request message (executed after step S312), the S-SN can perform normal data forwarding and send the SN state transition message to the S-MN.

[0059] S308, S-MN triggers UE to apply new configuration. Upon receiving the new configuration, the UE releases the SCG configuration of S-SN.

[0060] S310-S312, UE synchronizes with the target eNB.

[0061] For S314a-S314b, for a bearer terminating with SN using Radio Link Control Acknowledgment Mode (RLC AM), the S-SN sends an SN state transition message to the S-MN, and then the S-MN sends an SN state transition message to the target eNB.

[0062] S316, if applicable, allows for normal data forwarding from the S-SN.

[0063] S318a, the S-SN sends an auxiliary RAT data usage report message to the S-MN, wherein the auxiliary RAT data usage report message includes information about the amount of data sent to and received from the UE via NR radio resources for the relevant evolved radio access bearer (E-RAB).

[0064] Note 2: The order in which the S-SN sends the auxiliary RAT data usage report message to the S-MN and performs normal data forwarding is not specified. The S-SN may send the auxiliary RAT data usage report message when the relevant E-RAB transmission stops.

[0065] S318b, the S-MN sends an auxiliary RAT data usage report message to the Mobility Management Entity (MME) to provide information about the NR radio resources that will be used to carry data to and from the UE.

[0066] S320-S328, the target eNB initiates the S1 path switching process.

[0067] S330, the target eNB sends a UE context release message to the S-MN.

[0068] S332, upon receiving a UE context release message, the S-MN releases radio and control plane resources associated with the UE context data. Any ongoing data forwarding can continue.

[0069] Note 3: The above MN to eNB change process can also be used for UE inter-system handover from eNB to ng-eNB / gNB.

[0070] Figure 4 This example signaling flow illustrates the MeNB to eNB transition process in an LTE-DC scenario. The MeNB to eNB transition process can be used to transfer UE context data from the source primary eNB / secondary eNB (S-MeNB / SeNB) to the target eNB. The MeNB to eNB transition process includes:

[0071] S402, the S-MeNB sends a handover request message to the target eNB to initiate the X2 handover preparation process. The handover request message may include the SCG configuration of the S-SeNB.

[0072] S404, the target eNB sends a handover request confirmation message to the S-MeNB, wherein the handover request confirmation message may include a field indicating the release of the SCG configuration of the S-MeNB, and may also include the data forwarding address corresponding to the target eNB (if advance data forwarding for bearers terminated by the SN is required).

[0073] S406, if the target eNB's resource allocation is successful, the S-MeNB sends a SeNB release request message to the S-SeNB to initiate the release of S-SeNB's resources. Receiving the SeNB release request message triggers the S-SeNB to stop providing user data to the UE, and, if applicable, to begin normal data forwarding.

[0074] Note 1: In the case of UE's CHO, step S406 is executed after the S-MeNB receives an indication that the UE has successfully accessed the target eNB (i.e., after step S412).

[0075] Note 2: In the case of a UE's CHO, if early data forwarding for a bearer terminated by the SN is required, multiple data forwarding address indication messages can be sent from the S-MeNB to the S-SeNB immediately after step S404. The data forwarding address indication messages are used to notify the S-SeNB of the UE's CHO and provide the S-SeNB with data forwarding addresses corresponding to different candidate target ANs. The S-SeNB can then perform early data forwarding for the bearer terminated by the SN towards the data forwarding addresses corresponding to the different candidate target ANs and send an early state transition message to the S-MeNB. Source / target UE X2AP ID pairs can be included in each data forwarding address indication message, and these data forwarding address indication messages can be identified by the source / target UE X2AP ID pairs in the multiple data forwarding address indication messages. Source / target UE X2AP ID pairs can also be included in each early state transition message, and these early state transition messages can be identified by the source / target UE X2AP ID pairs in the early state transition messages sent in response to the multiple data forwarding address indication messages. Based on the source / destination UE X2AP ID pair contained in the data forwarding address indication message and the early state transition message, the correspondence between the data forwarding address indication message and the early state transition message can be determined. The data forwarding address indication message may also contain an early data forwarding stop indication to instruct the S-SN to stop early data forwarding already initiated for some SN-terminated bearers (if they no longer require early data forwarding due to modification or cancellation of the UE's CHO). If applicable, once the S-SeNB receives the SgNB release request message (executed after step S412), the S-SeNB can perform normal data forwarding and send an SN state transition message to the S-MeNB.

[0076] In S408, the S-MeNB triggers the UE to apply a new configuration. Upon receiving the new configuration, the UE releases the SCG configuration of the S-SeNB.

[0077] S410-S412, UE synchronizes with the target eNB.

[0078] S414a-S416, if applicable, allows for normal data forwarding from the S-SeNB. This can begin as early as when the S-SeNB receives the SeNB release request message from the S-MeNB.

[0079] S418-S426, the target eNB initiates the S1 path switching process.

[0080] S428, the target eNB sends a UE context release message to the S-MeNB.

[0081] S430, upon receiving a UE context release message, the S-SeNB can release radio and control plane resources associated with the UE context data. Any ongoing data forwarding can continue.

[0082] Implementation of Methods 200A and 200B in MR-DC and 5GC Scenarios

[0083] In an MR-DC scenario with 5GC, multiple data forwarding address indication messages can be implemented as XN-U ADDRESSINDICATION messages. The source identifier can be the source NG-RAN node UE XnAP identifier (ID), and the target identifier can be the target NG-RAN node UE XnAP ID.

[0084] In MR-DC scenarios with 5GC, the XN-U ADDRESS INDICATION message can be used to provide data forwarding from S-MN to S-SN or Xn-U bearer address.

[0085] In MR-DC scenarios with 5GC, the count value associated with the forwarded downlink serving data unit (SDU) is transferred from S-SN to S-MN using an very early state transition message during the UE's CHO.

[0086] The contents of the XN-U ADDRESS INDICATION message and the very early state transition message are shown in Table 3-4.

[0087] Table 3-XN-U ADDRESS INDICATION

[0088]

[0089] maxnoofPDUSsessions The maximum number value for a PDU session is 256.

[0090] If the CHOMRDC indicator is true If the CHO MR DC indicator IE exists and is set to "true", then IE should exist.

[0091] Table 4 - Very Early State Transitions

[0092]

[0093]

[0094] maxnoofDRBs The maximum DRB number value that can be forwarded to a UE is 32.

[0095] Figure 5 An example signaling flow for the MN to ng-eNB / gNB changeover process in an MR-DC scenario with 5GC is shown. The MN to ng-eNB / gNB changeover process can be used to transfer UE context data from the S-MN / SN to the target ng eNB / gNB, where the S-MN and the target ng-eNB / gNB can belong to the same radio access technology (i.e., they are both ng-eNBs or both gNBs) or different radio access technologies. Figure 5 As shown, the process of changing from MN to ng-eNB / gNB includes:

[0096] S502, S-MN sends a handover request message to the target ng-eNB / gNB to initiate the Xn handover preparation process. The handover request message may include the SCG configuration of S-SN and the MCG configuration of S-MN.

[0097] Note 1: Before step S502, S-MN can trigger the SN modification process initiated by MN to retrieve the SCG configuration of S-SN and allow the provision of data forwarding related information to S-SN.

[0098] S504, the target ng-eNB / gNB sends a handover request confirmation message to the S-MN. The handover request confirmation message may include a field indicating the release of the SCG configuration of the S-SN, and if early data forwarding for the bearer terminated by the SN is required, it may also include the data forwarding address corresponding to the target ng-eNB / gNB.

[0099] S506a, if the resource allocation for the target ng-eNB / gNB is successful, the S-MN sends an SN release request message to the S-SN, wherein the SN release request message may include a reason indicating the mobility of the MCG.

[0100] In S506b, the S-SN sends an SN release request confirmation message to the S-MN. Receiving the SN release request message triggers the S-SN to stop providing user data to the UE, and, if applicable, to begin normal data forwarding.

[0101] S506c, if early data forwarding is required for a bearer terminated by the SN, the S-MN sends multiple Xn-U address indication messages to the S-SN, wherein the multiple Xn-U address indication messages contain data forwarding addresses corresponding to different candidate target ANs.

[0102] • Note 1a: In the case of UE's CHO, after S-MN receives an indication that UE has successfully accessed the target ng-eNB / gNB (i.e., after step S512), steps S506a and S506b are executed.

[0103] Note 1b: In the case of a UE's CHO, step S506c is executed immediately after step S504. The Xn-U address indication message is used to notify the S-SN of the UE's CHO and provide the S-SN with data forwarding addresses corresponding to different candidate target ANs. The S-SN can then perform early data forwarding for bearers terminated by the SN towards the data forwarding addresses corresponding to different candidate target ANs and send an early state transition message to the S-MN. A source / target UE XnAP ID pair can be included in each Xn-U address indication message, and these Xn-U address indication messages can be identified by the source / target UE XnAP ID pairs in multiple Xn-U address indication messages. The source / target UE XnAP ID pair can also be included in each early state transition message, and these early state transition messages can be identified by the source / target UE XnAP ID pairs in the early state transition messages sent in response to multiple Xn-U address indication messages. Based on the source / target UE XnAP ID pair contained in the Xn-U address indication message and the early state transition message, the correspondence between the Xn-U address indication message and the early state transition message can be determined. The Xn-U address indication message may also include an early data forwarding stop indication to instruct the S-SN to stop early data forwarding that has been initiated for some SN-terminated bearers (if they no longer need early data forwarding due to modification or cancellation of the UE's CHO procedure). If applicable, once the S-SN receives the SN release request message, the S-SN can perform normal data forwarding and send the SN state transition message to the S-MN. If the Xn-U address indication message corresponding to the target ng-eNB / gNB to which the UE has successfully accessed is rejected by the S-SN (i.e., the S-MN has not yet received the corresponding early state transition message), the S-MN retransmits the message after step S506b, which is executed after step S512.

[0104] S508, the S-MN triggers the UE to perform a handover and apply the new configuration. Upon receiving the new configuration, the UE releases the SCG configuration of the S-SN.

[0105] S510-S512, UE synchronizes to the target ng-eNB / gNB.

[0106] In S514a-S514b, if the Packet Data Convergence Protocol (PDCP) termination point of the bearer using RLC AM changes, the S-SN sends an SN state transition message to the S-MN, and then the S-MN sends an SN state transition message to the target ng-eNB / gNB.

[0107] S516, if applicable, performs normal data forwarding from the S-SN.

[0108] S518a, the S-SN sends an auxiliary RAT data usage report message to the S-MN, wherein the auxiliary RAT data usage report message includes information about the amount of data delivered to and received from the UE via NR radio resources for the relevant E-RAB.

[0109] Note 2: The order in which the S-SN sends the auxiliary RAT data usage report message and performs normal data forwarding is not specified. The S-SN may send the auxiliary RAT data usage report message when the transmission of the relevant Quality of Service (QoS) stream stops.

[0110] In S518b, the S-MN sends an auxiliary RAT report message to the Authentication Management Function (AMF) entity to provide information about the NR / E-UTRA resources used to carry data delivered to and received from the UE.

[0111] S520-S528, the target ng-eNB / gNB initiates the path switching process.

[0112] S530, the target ng-eNB / gNB sends a UE context release message to the S-MN.

[0113] S532, when a UE context release message is received from the S-MN, the S-SN releases the radio and control plane resources associated with the UE context data. Any ongoing data forwarding can continue.

[0114] Note 3: The above MN to ng-eNB / gNB change process can be used for UE inter-system handover from ng-eNB / gNB to eNB.

[0115] Figure 6-7 Various systems, devices, and components are shown that can implement multiple aspects of the disclosed embodiments.

[0116] Figure 6A schematic diagram of a network 600 according to various embodiments of the present disclosure is shown. Network 600 can operate according to the 3GPP technical specifications of Long Term Evolution (LTE) or 5G / NR systems. However, exemplary embodiments are not limited in this respect, and the described embodiments can be applied to other networks that benefit from the principles described herein, such as future 3GPP systems, etc.

[0117] Network 600 may include UE 602, which may include any mobile or non-mobile computing device designed to communicate with Radio Access Network (RAN) 604 via an over-the-air connection. UE 602 may be, but is not limited to, smartphones, tablets, wearable computing devices, desktop computers, laptops, in-vehicle infotainment devices, in-vehicle entertainment devices, dashboards, head-up displays, in-vehicle diagnostic devices, dashboard mobile devices, mobile data terminals, electronic engine management systems, electronic / engine control units, electronic / engine control modules, embedded systems, sensors, microcontrollers, control modules, engine management systems, network devices, machine-to-machine (M2M) or device-to-device (D2D) devices, Internet of Things (IoT) devices, etc.

[0118] In some embodiments, network 600 may include multiple UEs that are directly coupled to each other via secondary link interfaces. The UEs may be M2M / D2D devices that communicate using physical secondary link channels (e.g., but not limited to physical secondary link broadcast channel (PSBCH), physical secondary link discovery channel (PSDCH), physical secondary link shared channel (PSSCH), physical secondary link control channel (PSCCH), physical secondary link basic channel (PSFCH), etc.).

[0119] In some embodiments, UE 602 can also communicate with access point (AP) 606 via an over-the-air connection. AP 606 can manage wireless local area network (WLAN) connections and can be used to offload some / all network traffic from RAN 604. The connection between UE 602 and AP 606 can be consistent with any IEEE 802.11 protocol, wherein AP 606 can be Wireless Fibre Channel. Router. In some embodiments, UE 602, RAN 604, and AP 606 may utilize cellular WLAN aggregation (e.g., LTE-WLAN aggregation (LWA) / Lightweight IP (LWIP)). Cellular WLAN aggregation may involve RAN 604 configuring UE 602 to utilize both cellular radio resources and WLAN resources.

[0120] RAN 604 may include one or more access nodes, such as Access Node (AN) 608. AN 608 can terminate the air interface protocol of UE 602 by providing access layer protocols including Radio Resource Control (RRC), Packet Data Convergence Protocol (PDCP), Radio Link Control (RLC), Media Access Control (MAC), and L1 protocol. In this way, AN 608 enables data / voice connectivity between Core Network (CN) 620 and UE 602. In some embodiments, AN 608 may be implemented in discrete devices or as one or more software entities running on a server computer (as part of, for example, a virtual network, which may be referred to as a Distributed RAN (CRAN) or a virtual baseband unit pool). AN 608 may be referred to as a Base Station (BS), Next Generation Base Station (gNB), RAN Node, Evolved Node B (eNB), Next Generation eNB (ng eNB), Node B (NodeB), Roadside Unit (RSU), Transmit Receive Point (TRxP), Transmit Point (TRP), etc. AN608 can be a macro cell base station or a low-power base station, used to provide microcells, picocells, or other similar cells with smaller coverage areas, smaller user capacity, or higher bandwidth compared to macrocells.

[0121] In embodiments where RAN 604 includes multiple ANs, they can be coupled to each other via an X2 interface (if RAN 604 is an LTE RAN) or an Xn interface (if RAN 604 is a 5G RAN). In some embodiments, the X2 / Xn interfaces, which can be separated into control / user plane interfaces, can allow ANs to transmit and handover, data / context transfer, mobility, load management, interference coordination, and other related information.

[0122] The AN of RAN 604 can manage one or more cells, cell groups, component carriers, etc., to provide an air interface for network access to UE 602. UE 602 can simultaneously connect to multiple cells provided by the same or different ANs of RAN 604. For example, UE 602 and RAN 604 can use carrier aggregation to allow UE 602 to connect to multiple component carriers, each component carrier corresponding to a primary cell (PCell) or a secondary cell (SCell). In a dual-connectivity scenario, the first AN can be the primary network node providing the primary cell group (MCG), and the second AN can be the secondary network node providing the secondary cell group (SCG). The first / second AN can be any combination of eNB, gNB, ng-eNB, etc.

[0123] RAN 604 can provide an air interface on either licensed or unlicensed spectrum. To operate in unlicensed spectrum, nodes can use Licensed Assisted Access (LAA), enhanced LAA (eLAA), and / or further enhanced LAA (feLAA) mechanisms based on PCell / Scell ​​carrier aggregation (CA) technology. Before accessing unlicensed spectrum, nodes can perform medium / carrier sensing operations based on, for example, a Listen-After-Speak (LBT) protocol.

[0124] In a vehicle-to-everything (V2X) scenario, UE 602 or AN 608 can be or act as a roadside unit (RSU), which can refer to any transportation infrastructure entity used for V2X communication. The RSU can be implemented in or by a suitable AN or a stationary (or relatively stationary) UE. An RSU implemented in or by a UE can be referred to as a "UE-type RSU"; an RSU implemented in or by an eNB can be referred to as an "eNB-type RSU"; an RSU implemented in or by a next-generation NodeB (gNB) can be referred to as a "gNB-type RSU," and so on. In one example, the RSU is a computing device coupled to radio frequency circuitry located on the roadside, providing connectivity support to passing vehicle UEs. The RSU may also include internal data storage circuitry for storing intersection map geometry, traffic statistics, media, and applications / software for sensing and controlling ongoing vehicle and pedestrian traffic. The RSU can provide very low-latency communication required for high-speed events such as collision avoidance, traffic warnings, etc. Alternatively or additionally, the RSU can provide other cellular / WLAN communication services. RSU components can be enclosed in a weatherproof enclosure suitable for outdoor installation and may include a network interface controller to provide wired connectivity (e.g., Ethernet) to traffic signal controllers or backhaul networks.

[0125] In some embodiments, RAN 604 may be LTE RAN 610, which includes an evolved Node B (eNB), such as eNB 612. LTE RAN 610 can provide an LTE air interface with the following characteristics: a 15 kHz subcarrier spacing (SCS); a single-carrier frequency division multiple access (SC-FDMA) waveform for uplink (UL) and a cyclic prefix orthogonal frequency division multiplexing (CP-OFDM) waveform for downlink (DL); turbo codes for data and TBCC for control, etc. The LTE air interface may rely on Channel State Information Reference Signal (CSI-RS) for CSI acquisition and beam management; rely on Physical Downlink Shared Channel (PDSCH) / Physical Downlink Control Channel (PDCCH) Demodulation Reference Signal (DMRS) for PDSCH / PDCCH demodulation; and rely on Cell Reference Signal (CRS) for cell search and initial acquisition, channel quality measurement, and channel estimation, and rely on channel estimation for coherent demodulation / detection at the UE. The LTE air interface can operate on a 6 GHz subband.

[0126] In some embodiments, RAN 604 may be a next-generation (NG) RAN 614 with a gNB (e.g., gNB 616) or a gn-eNB (e.g., ng-eNB 618). gNB 616 can connect to a 5G-enabled UE using a 5G NR interface. gNB 616 can connect to the 5G core via an NG interface, which may include an N2 interface or an N3 interface. ng-eNB 618 can also connect to the 5G core via an NG interface, but can connect to the UE via an LTE air interface. gNB 616 and ng-eNB 618 can connect to each other via an Xn interface.

[0127] In some embodiments, the NG interface can be divided into two parts: the NG user plane (NG-U) interface and the NG control plane (NG-C) interface. The former carries traffic data between the nodes of UPF 648 and NG-RAN 614 (e.g., the N3 interface), while the latter is the signaling interface between the nodes of Access and Mobility Management Function (AMF) 644 and NG-RAN 614 (e.g., the N2 interface).

[0128] NG-RAN 614 can provide a 5G-NR air interface with the following features: Variable Subcarrier Spacing (SCS); Cyclic Prefix-Orthogonal Frequency Division Multiplexing (CP-OFDM) for downlink (DL), CP-OFDM and DFT-s-OFDM for UL; Polarity, Repetition, Simplex, and Reed-Muller codes for control; and Low-Density Parity-Check (LDPC) codes for data. The 5G-NR air interface can rely on Channel State Reference Signals (CSI-RS) and PDSCH / PDCCH Demodulation Reference Signals (DMRS), similar to the LTE air interface. The 5G-NR air interface may not use Cell Reference Signals (CRS), but can use Physical Broadcast Channel (PBCH) Demodulation Reference Signals (DMRS) for PBCH demodulation; Phase Tracking Reference Signals (PTRS) for PDSCH phase tracking; and Tracking Reference Signals for time tracking. The 5G-NR air interface can operate on the FR1 band, which includes the 6GHz sub-band, or the FR2 band, which includes the 24.25GHz to 52.6GHz band. The 5G-NR air interface can include synchronization signals and PBCH blocks (SSBs), where an SSB is an area of ​​the downlink resource grid that includes the primary synchronization signal (PSS), secondary synchronization signal (SSS), and PBCH.

[0129] In some embodiments, the 5G-NR air interface can use the bandwidth portion (BWP) for various purposes. For example, the BWP can be used for dynamic adaptation of the SCS. For instance, UE 602 can be configured with multiple BWPs, each configured with a different SCS. When UE 602 is instructed to change a BWP, the transmitted SCS also changes. Another use case for BWPs relates to power saving. Specifically, multiple BWPs with different numbers of frequency resources (e.g., PRBs) can be configured for UE 602 to support data transmission under different traffic load scenarios. A BWP containing fewer PRBs can be used for data transmission with lower traffic loads, while allowing power saving at UE 602 and, in some cases, at gNB 616. A BWP containing more PRBs can be used for scenarios with higher traffic loads.

[0130] RAN 604 is communicatively coupled to CN 620, which includes network elements, to provide various functions supporting data and telecommunications services to customers / subscribers (e.g., users of UE 602). Components of CN 620 can be implemented in a single physical node or in different physical nodes. In some embodiments, network function virtualization (NFV) can be used to virtualize any or all of the functions provided by the network elements of CN 620 onto physical compute / storage resources such as servers, switches, etc. Logical instances of CN 620 can be referred to as network slices, and logical instances of a portion of CN 620 can be referred to as network subslices.

[0131] In some embodiments, CN 620 may be LTE CN 622, or may also be referred to as EPC. LTE CN 622 may include a Mobility Management Entity (MME) 624, a Serving Gateway (SGW) 626, a Serving General Packet Radio Service (GPRS) Support Node (SGSN) 628, a Home Subscriber Server (HSS) 630, a Proxy Gateway (PGW) 632, and a Policy Control and Charging Rules Function (PCRF) 634, as shown in the figure. These components are coupled to each other through interfaces (or “reference points”). The functions of the elements of LTE CN 622 can be briefly described below.

[0132] The MME 624 enables mobility management functions to track the current location of the UE 602, thereby facilitating paging, bearer activation / deactivation, handover, gateway selection, authentication, and other functions.

[0133] The SGW 626 can terminate the S1 interface toward the RAN and route data packets between the RAN and the LTE CN 622. The SGW 626 can serve as a local mobility anchor for inter-RAN node handover and can also provide anchoring for inter-3GPP mobility. Other responsibilities may include lawful interception, charging, and some policy enforcement.

[0134] SGSN 628 can track the location of UE 602 and perform security functions and access control. Additionally, SGSN 628 can perform EPC inter-node signaling for mobility between different RAT networks; PDN and S-GW selection specified by MME 624; MME selection for handover, etc. The S3 reference point between MME 624 and SGSN 628 enables the exchange of user and bearer information for 3GPP indirect access network mobility in idle / active states.

[0135] The HSS 630 may include a database for network users, containing subscription-related information that supports network entities in handling communication sessions. The HSS 630 can provide support for routing / roaming, authentication, authorization, naming / addressing resolution, location dependencies, etc. An S6a reference point between the HSS 630 and the MME 624 enables the transmission of subscription and authentication data for authenticating / authorizing user access to the LTE CN 620.

[0136] The PGW 632 can terminate the SGi interface toward a data network (DN) 636, which may include an application / content server 638. The PGW 632 can route data packets between the LTE CN 622 and the data network 636. The PGW 632 can be coupled to the SGW 626 via an S5 reference point to facilitate user plane tunneling and tunnel management. The PGW 632 may also include nodes for policy enforcement and charging data collection (e.g., PCEF). Additionally, the SGi reference point between the PGW 632 and the data network 636 can be, for example, an external public or private PDN or an internal packet data network for providing IP Multimedia Subsystem (IMS) services. The PGW 632 can be coupled to the PCRF 634 via a Gx reference point.

[0137] PCRF 634 is the policy and charging control element of LTE CN 622. PCRF 634 can be communicatively coupled to application / content server 638 to determine appropriate Quality of Service (QoS) and charging parameters for service flows. PCRF 632 can provide relevant rules to PCEF (via Gx reference point) with appropriate Service Flow Template (TFT) and QoS Class Identifier (QCI).

[0138] In some embodiments, CN 620 may be a 5G core network (5GC) 640. 5GC 640 may include an Authentication Server Function (AUSF) 642, Access and Mobility Management Function (AMF) 644, Session Management Function (SMF) 646, User Plane Function (UPF) 648, Network Slice Selection Function (NSSF) 650, Network Open Function (NEF) 652, Network NF Storage Function (NRF) 654, Policy Control Function (PCF) 656, Unified Data Management (UDM) 658, and Application Function (AF) 660, as shown in the figure. These functions are coupled to each other through interfaces (or "reference points"). The functions of the components of 5GC 640 can be briefly described below.

[0139] The AUSF 642 can store data for UE 602 authentication and handle authentication-related functions. The AUSF 642 facilitates a common authentication framework for various access types. In addition to communicating with other components of the 5GC 640 via a reference point, as shown in the figure, the AUSF 642 can also demonstrate an interface based on Nausf services.

[0140] AMF 644 allows 5GC 640 to communicate with UE 602 and RAN 604, and subscribe to notifications regarding mobility events for UE 602. AMF 644 can handle registration management (e.g., registering UE 602), connection management, reachability management, mobility management, lawful interception of AMF-related events, and access authentication and authorization. AMF 644 can provide the transmission of Session Management (SM) messages between UE 602 and SMF 646, and acts as a transparent broker for routing SM messages. AMF 644 can also provide the transmission of SMS messages between UE 602 and SMSF. AMF 644 can interact with AMFF 642 and UE 602 to perform various security anchoring and context management functions. Furthermore, AMF 644 can be the termination point of the RAN CP interface, which may include or be the N2 reference point between RAN 604 and AMF 644; AMF 644 can serve as the termination point for NAS (N1) signaling and perform NAS encryption and integrity protection. The AMF 644 can also support NAS signaling with the UE 602 via the N3 IWF interface.

[0141] SMF 646 can be responsible for SM (e.g., tunnel management and session establishment between UPF 648 and AN 608); UE IP address allocation and management (including optional authorization); selection and control of UP functions; configuring flow control at UPF 648 to route traffic to appropriate destinations; termination of interfaces to policy control functions; control of policy enforcement, charging, and QoS as a part; lawful interception (for SM events and interfaces to the LI system); termination of the SM portion of NAS messages; downlink data notification; initiating AN-specific SM information (sent to AN 608 on N2 via AMF 644); and determining the SSC mode of the session. SM can refer to the management of PDU sessions, and a PDU session or "session" can refer to the PDU connectivity service that provides or enables PDU exchange between UE 602 and data network 636.

[0142] The UPF 648 can be used as an anchor point for mobility within and between RATs, an external PDU session point interconnecting with the data network 636, and a branch point supporting multi-homed PDU sessions. The UPF 648 can also perform packet routing and forwarding, packet inspection, user plane portion of policy rules, lawful packet interception (UP collection), traffic usage reporting, QoS processing for the user plane (e.g., packet filtering, gating, UL / DL rate enforcement), uplink traffic authentication (e.g., SDF-to-QoS flow mapping), transport-level packet marking in uplink and downlink, and downlink packet buffering and downlink data notification triggering. The UPF 648 may include an uplink classifier to support traffic flow routing to the data network.

[0143] NSSF 650 can select a set of network slice instances to serve UE 602. If needed, NSSF 650 can also determine the allowed network slice selection assistance information (NSSAI) and the mapping to the subscribed individual NSSAI (S-NSSAI). NSSF 650 can also determine the set of AMFs to be used to serve UE 602 based on appropriate configuration and possibly by querying NRF 654, or determine a list of candidate AMFs. The selection of a set of network slice instances for UE 602 can be triggered by AMF 644 (to which UE 602 registers by interacting with NSSF 650), resulting in a change of AMF. NSSF 650 can interact with AMF 644 via reference point N22; and can communicate with another NSSF in the access network via reference point N31 (not shown). Furthermore, NSSF 650 can expose an interface based on NNSSF services.

[0144] NEF 652 can securely expose services and capabilities provided by 3GPP network functions to third parties, internal exposure / re-exposure, AFs (e.g., AF 660), edge computing, or fog computing systems. In these embodiments, NEF 652 can authenticate, authorize, or restrict AFs. NEF 652 can also translate information exchanged with AF 660 and information exchanged with internal network functions. For example, NEF 652 can translate between AF service identifiers and internal 5GC information. NEF 652 can also receive information from other NFs based on their exposed capabilities. This information can be stored as structured data at NEF 652 or stored at a data storage NF using a standardized interface. NEF 652 can then re-expose the stored information to other NFs and AFs, or use it for other purposes such as analytics. Additionally, NEF 652 can expose interfaces based on Nnef services.

[0145] NRF 654 supports service discovery, receiving NF discovery requests from NF instances and providing information about discovered NF instances to those instances. NRF 654 also maintains information about available NF instances and the services they support. As used herein, the terms "instantiation," "instance," etc., can refer to the creation of an instance, and an "instance" can refer to the concrete occurrence of an object, such as during program code execution. Furthermore, NRF 654 can demonstrate interfaces based on NRF services.

[0146] PCF 656 can provide policy rules to control plane functions for enforcement and supports a unified policy framework for managing network behavior. PCF 656 can also implement a front-end to access subscription information related to policy decisions in the UDR of UDM 658. In addition to communicating with functions via reference points as shown in the figure, PCF 656 also demonstrates an interface based on NPCF services.

[0147] UDM 658 can process subscription-related information to support network entities in handling communication sessions and can store subscription data for UE 602. For example, subscription data can be transmitted via the N8 reference point between UDM 658 and AMF 644. UDM 658 can include two parts: an application front-end and a User Data Record (UDR). The UDR can store policy data and subscription data for UDM 658 and PCF 656, and / or structured data and application data for exposure (including PFDs for application detection and application request information for multiple UEs 602) for NEF 652. UDR 221 can expose a Nudr service-based interface to allow UDM 658, PCF 656, and NEF 652 to access specific sets of stored data, as well as to read, update (e.g., add, modify), delete, and subscribe to notifications of relevant data changes in the UDR. UDM may include UDM-FE (UDM front-end), which is responsible for handling credentials, location management, subscription management, etc. Several different front-ends can provide services to the same user in different transactions. The UDM-FE accesses subscription information stored in the UDR and performs authentication credential processing, user identification processing, access authorization, registration / mobility management, and subscription management. In addition to communicating with other NFs via reference points as shown in the figure, the UDM 658 can also demonstrate interfaces based on Nudm services.

[0148] The AF 660 can provide application impact on service routing, provide access to NEF, and interact with the policy framework for policy control.

[0149] In some embodiments, 5GC 640 can enable edge computing by selecting an operator / third-party service that is geographically close to the point where UE 602 connects to the network. This can reduce latency and load on the network. To provide edge computing implementation, 5GC 640 can select a UPF 648 close to UE 602 and perform traffic routing from UPF 648 to data network 636 via the N6 interface. This can be based on UE subscription data, UE location, and information provided by AF 660. In this way, AF 660 can influence UPF (re)selection and service routing. Based on operator deployment, when AF 660 is considered a trusted entity, the network operator can allow AF 660 to interact directly with the relevant NF. Additionally, AF 660 can expose interfaces based on Naf services.

[0150] Data network 636 can represent various network operator services, Internet access, or third-party services that can be provided by one or more servers (including, for example, application / content server 638).

[0151] Figure 7 A wireless network 700 according to various embodiments is schematically illustrated. The wireless network 700 may include a UE 702 that communicates wirelessly with an AN 704. The UE 702 and the AN 704 may be similar to and substantially interchangeable with components of the same name described elsewhere herein.

[0152] UE 702 can be communicatively coupled to AN 704 via connection 706. Connection 706 is shown as an air interface to enable communication coupling and can operate at millimeter wave or sub-6 GHz frequencies according to cellular communication protocols such as LTE or 5G NR.

[0153] UE 702 may include a host platform 708 coupled to a modem platform 710. Host platform 708 may include application processing circuitry 712, which may be coupled to protocol processing circuitry 714 of the modem platform 710. Application processing circuitry 712 may run various applications for UE 702 to acquire / receive its application data. Application processing circuitry 712 may also implement one or more layer operations to send / receive application data to / from a data network. These layer operations may include transport (e.g., UDP) and Internet (e.g., IP) operations.

[0154] Protocol processing circuitry 714 can implement one or more layer operations to facilitate the transmission or reception of data via connection 706. Layer operations implemented by protocol processing circuitry 714 may include, for example, Media Access Control (MAC), Radio Link Control (RLC), Packet Data Convergence Protocol (PDCP), Radio Resource Control (RRC), and Non-Access Stratum (NAS) operations.

[0155] The modem platform 710 may further include a digital baseband circuit 716 that can implement one or more layer operations "below" the layer operations performed by the protocol processing circuit 714 in the network protocol stack. These operations may include, for example, one or more of the following PHY operations: HARQ-ACK function, scrambling / descrambling, encoding / decoding, layer mapping / demapping, modulation symbol mapping, received symbol / bit metric determination, multi-antenna port precoding / decoding. These functions may include one or more of the following: space-time, space-frequency, or spatial coding; reference signal generation / detection; preamble sequence generation and / or decoding; synchronization sequence generation / detection; blind decoding of control channel signals; and other related functions.

[0156] The modem platform 710 may further include transmitting circuitry 718, receiving circuitry 720, RF circuitry 722, and RF front-end (RFFE) circuitry 724, which may include or be connected to one or more antenna panels 726. In short, transmitting circuitry 718 may include a digital-to-analog converter, mixer, intermediate frequency (IF) component, etc.; receiving circuitry 720 may include an analog-to-digital converter, mixer, IF component, etc.; RF circuitry 722 may include a low-noise amplifier, power amplifier, power point tracking component, etc.; RFFE circuitry 724 may include filters (e.g., surface acoustic wave filters), switches, antenna tuners, beamforming components (e.g., phased array antenna components), etc. The selection and arrangement of the components of transmitting circuitry 718, receiving circuitry 720, RF circuitry 722, RFFE circuitry 724, and antenna panels 726 (collectively, the "transmit / receive assembly") may be specific to implementation details, such as whether the communication is time-division multiplexing (TDM) or frequency-division multiplexing (FDM), at mmWave or below 6 GHz frequencies, etc. In some embodiments, the transmit / receive components may be arranged in multiple parallel transmit / receive chains and may be arranged in the same or different chips / modules, etc.

[0157] In some embodiments, the protocol processing circuit 714 may include one or more instances of control circuitry (not shown) to provide control functions for the transmitting / receiving components.

[0158] UE reception can be established via and through antenna panel 726, RFFE circuit 724, RF circuit 722, receiving circuit 720, digital baseband circuit 716, and protocol processing circuit 714. In some embodiments, antenna panel 726 can receive transmissions from AN 704 by receiving beamforming signals received by a plurality of antennas / antenna elements of one or more antenna panels 726.

[0159] UE transmission can be established via and through protocol processing circuitry 714, digital baseband circuitry 716, transmission circuitry 718, RF circuitry 722, RFFE circuitry 724, and antenna panel 726. In some embodiments, the transmission component of UE 702 can apply spatial filtering to the data to be transmitted to form a transmission beam emitted by the antenna elements of antenna panel 726.

[0160] Similar to UE 702, AN 704 may include a host platform 728 coupled to a modem platform 730. The host platform 728 may include application processing circuitry 732 coupled to protocol processing circuitry 734 of the modem platform 730. The modem platform may also include digital baseband circuitry 736, transmit circuitry 738, receive circuitry 740, RF circuitry 742, RFFE circuitry 744, and antenna panel 746. Components of AN 704 may be similar to their namesakes in UE 702 and are substantially interchangeable with their namesakes in UE 702. In addition to performing data transmission / reception as described above, components of AN 704 may perform various logical functions, including, for example, Radio Network Controller (RNC) functions such as radio bearer management, uplink and downlink dynamic radio resource management, and packet scheduling.

[0161] Figure 8 This is a block diagram illustrating components capable of reading instructions from a machine-readable or computer-readable medium (e.g., a non-transitory machine-readable storage medium) and performing any one or more of the methods discussed herein, according to some example embodiments. Specifically, Figure 8 A schematic diagram of hardware resource 800 is shown, which includes one or more processors (or processor cores) 810, one or more memory / storage devices 820, and one or more communication resources 830, wherein each of these processors, memory / storage devices, and communication resources can be communicatively coupled via bus 840 or other interface circuitry. For embodiments utilizing node virtualization (e.g., Network Functions Virtualization (NFV)), a hypervisor 802 can be executed to provide an execution environment for one or more network slices / subslices, thereby utilizing hardware resource 800.

[0162] Processor 810 may include, for example, processor 812 and processor 814. Processor 810 may be, for example, a central processing unit (CPU), a reduced instruction set computing (RISC) processor, a complex instruction set computing (CISC) processor, a graphics processing unit (GPU), a digital signal processor (DSP) such as a baseband processor, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a radio frequency integrated circuit (RFIC), another processor (including those discussed herein), or any suitable combination thereof.

[0163] The memory / storage device 820 may include main memory, disk storage devices, or any suitable combination thereof. The memory / storage device 820 may include, but is not limited to, any type of volatile, non-volatile, or semi-volatile memory, such as dynamic random access memory (DRAM), static random access memory (SRAM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), flash memory, solid-state memory, etc.

[0164] Communication resource 830 may include an interconnect or network interface controller, component, or other suitable device for communicating via network 808 with one or more peripheral devices 804 or one or more databases 806 or other network elements. For example, communication resource 830 may include wired communication components (e.g., for coupling via USB, Ethernet, etc.), cellular communication components, near field communication (NFC) components, etc. (or Low-energy components Components and other communication components.

[0165] Instruction 850 may include software, a program, application program, applet, or other executable code for causing at least any one of the processors 810 to perform any one or more of the methods discussed herein. Instruction 850 may reside wholly or partially within processor 810 (e.g., in the processor's cache), memory / storage device 820, or any suitable combination thereof. Furthermore, any portion of instruction 850 may be transferred from any combination of peripheral device 804 or database 806 to hardware resource 800. Therefore, the memory of processor 810, memory / storage device 820, peripheral device 804, and database 806 are examples of computer-readable and machine-readable media.

[0166] The following paragraphs describe examples of various embodiments.

[0167] Example 1 includes an apparatus for use in an access node (AN), wherein the AN functions as a primary node (MN) connected to a secondary node (SN) via an X2 or Xn interface in a Long Term Evolution-Dual Connectivity (LTE-DC) or Multiple Radio Access Technology-Dual Connectivity (MR-DC) scenario. The AN includes processor circuitry configured such that, during a Conditional Handover (CHO) process of a user equipment (UE), the AN: sends a plurality of data forwarding address indication messages to the SN, wherein each of the plurality of data forwarding address indication messages contains a data forwarding address corresponding to a candidate target AN; and for each of the plurality of data forwarding address indication messages, receives an early state transition message or a fault report message sent by the SN in response to that data forwarding address indication message.

[0168] Example 2 includes the apparatus described in Example 1, wherein each of the plurality of data forwarding address indication messages further includes a source identifier and a target identifier, the source identifier uniquely identifying the association between the UE and the MN, and the target identifier uniquely identifying the association between the UE and the candidate target AN.

[0169] Example 3 includes the apparatus described in Example 1, wherein the very early state transition message includes a source identifier and a target identifier, the source identifier uniquely identifying the association between the UE and the MN, and the target identifier uniquely identifying the association between the UE and the candidate target AN.

[0170] Example 4 includes the apparatus described in Example 1, wherein each of the plurality of data forwarding address indication messages further includes an early data forwarding stop indication to indicate to the SN whether to stop early data forwarding that has been initiated for bearers terminated by some SNs.

[0171] Example 5 includes the apparatus described in Example 1, wherein, in an MR-DC scenario with a 5G core (5GC), the plurality of data forwarding address indication messages are implemented as XN-UADDRESS INDICATION messages.

[0172] Example 6 includes the apparatus described in Example 1, wherein, in the LTE-DC scenario or the MR-DC scenario with an evolved packet core (EPC), the plurality of data forwarding address indication messages are implemented as DATA FORWARDING ADDRESSINDICATION messages.

[0173] Example 7 includes the apparatus described in Example 2 or 3, wherein, in an MR-DC scenario with a 5G core (5GC), the source identifier is the source NG-RAN node UE XnAP identifier (ID) and the target identifier is the target NG-RAN node UE XnAPID.

[0174] Example 8 includes the apparatus described in Example 2 or 3, wherein, in the LTE-DC scenario or the MR-DC scenario with an evolved packet core (EPC), the source identifier includes at least one of a source eNB UE X2AP identifier (ID) and a source eNB UE X2AP ID extension, and the target identifier includes at least one of a target eNB UE X2AP ID and a target eNB UE X2AP ID extension.

[0175] Example 9 includes an apparatus for use in an access node (AN), wherein the AN is used as a secondary node (SN) connected to a primary node (MN) via an X2 or Xn interface in a Long Term Evolution-Dual Connectivity (LTE-DC) or Multiple Radio Access Technology-Dual Connectivity (MR-DC) scenario, the AN including processor circuitry configured such that, during a Conditional Handover (CHO) procedure of a user equipment (UE): the AN receives from the MN a plurality of data forwarding address indication messages, wherein each of the plurality of data forwarding address indication messages contains a data forwarding address corresponding to a candidate target AN; and for each of the plurality of data forwarding address indication messages, when performing early data forwarding for a bearer terminated by the SN toward the data forwarding address contained in the data forwarding address indication message, the AN sends an early state transition message to the MN.

[0176] Example 10 includes the apparatus of Example 9, wherein the processor circuitry is further configured such that the AN: when no advance data forwarding for a bearer terminated by the SN is performed toward the data forwarding address contained in the data forwarding address indication message, sends a fault report message to the MN.

[0177] Example 11 includes the apparatus of Example 9, wherein each of the plurality of data forwarding address indication messages further includes a source identifier and a target identifier, the source identifier uniquely identifying the association between the UE and the MN, and the target identifier uniquely identifying the association between the UE and the candidate target AN.

[0178] Example 12 includes the apparatus described in Example 9, wherein the very early state transition message includes a source identifier and a target identifier, the source identifier uniquely identifying the association between the UE and the MN, and the target identifier uniquely identifying the association between the UE and the candidate target AN.

[0179] Example 13 includes the apparatus of Example 9, wherein each of the plurality of data forwarding address indication messages further includes an early data forwarding stop indication to indicate to the SN whether to stop early data forwarding that has been initiated for a portion of a bearer terminated by the SN.

[0180] Example 14 includes the apparatus described in Example 9, wherein, in an MR-DC scenario with a 5G core (5GC), the plurality of data forwarding address indication messages are implemented as XN-UADDRESS INDICATION messages.

[0181] Example 15 includes the apparatus described in Example 9, wherein, in the LTE-DC or MR-DC scenario with Evolved Packet Core (EPC), the plurality of data forwarding address indication messages are implemented as DATA FORWARDING ADDRESSINDICATION messages.

[0182] Example 16 includes the apparatus described in Example 11 or 12, wherein, in an MR-DC scenario with a 5G core (5GC), the source identifier is the source NG-RAN node UE XnAP identifier (ID) and the target identifier is the target NG-RAN node UE XnAPID.

[0183] Example 17 includes the apparatus described in Example 11 or 12, wherein, in the LTE-DC scenario or the MR-DC scenario with an evolved packet core (EPC), the source identifier includes at least one of a source eNB UE X2AP identifier (ID) and a source eNB UE X2AP ID extension, and the target identifier includes at least one of a target eNB UE X2AP ID and a target eNB UE X2AP ID extension.

[0184] Example 18 includes the apparatus described in Example 13, wherein the processor circuitry is further configured such that the AN: when the advance data forwarding stop indication indicates to stop advance data forwarding already initiated for a portion of the bearer terminated by the SN, stops advance data forwarding already initiated for that portion of the bearer terminated by the SN.

[0185] Example 19 includes a method for use in an access node (AN), wherein the AN is used as a master node (MN) connected to a secondary node (SN) via an X2 or Xn interface in a Long Term Evolution-Dual Connectivity (LTE-DC) or Multiple Radio Access Technology-Dual Connectivity (MR-DC) scenario, the method comprising: providing a plurality of data forwarding address indication messages to the radio interface for transmission to the SN during a Conditional Handover (CHO) procedure of a user equipment (UE), wherein each of the plurality of data forwarding address indication messages contains a data forwarding address corresponding to a candidate target AN; and for each of the plurality of data forwarding address indication messages, receiving an early state transition message or a fault report message transmitted by the SN in response to the data forwarding address indication message.

[0186] Example 20 includes the method of Example 19, wherein each of the plurality of data forwarding address indication messages further includes a source identifier and a target identifier, the source identifier uniquely identifying the association between the UE and the MN, and the target identifier uniquely identifying the association between the UE and the candidate target AN.

[0187] Example 21 includes the method described in Example 19, wherein the very early state transition message includes a source identifier and a target identifier, the source identifier uniquely identifying the association between the UE and the MN, and the target identifier uniquely identifying the association between the UE and the candidate target AN.

[0188] Example 22 includes the method of Example 19, wherein each of the plurality of data forwarding address indication messages further includes an early data forwarding stop indication to indicate to the SN whether to stop early data forwarding that has been initiated for some SN-terminated bearers.

[0189] Example 23 includes the method described in Example 19, wherein, in an MR-DC scenario with a 5G core (5GC), the plurality of data forwarding address indication messages are implemented as XN-UADDRESS INDICATION messages.

[0190] Example 24 includes the method described in Example 19, wherein, in the LTE-DC scenario or the MR-DC scenario with an evolved packet core (EPC), the plurality of data forwarding address indication messages are implemented as DATA FORWARDINGADDRESS INDICATION messages.

[0191] Example 25 includes the method described in Example 20 or 21, wherein, in an MR-DC scenario with a 5G core (5GC), the source identifier is the source NG-RAN node UE XnAP identifier (ID), and the target identifier is the target NG-RAN node UE XnAPID.

[0192] Example 26 includes the method described in Example 20 or 21, wherein, in the LTE-DC scenario or the MR-DC scenario with an evolved packet core (EPC), the source identifier includes at least one of a source eNB UE X2AP identifier (ID) and a source eNB UE X2AP ID extension, and the target identifier includes at least one of a target eNB UE X2AP ID and a target eNB UE X2AP ID extension.

[0193] Example 27 includes a method for use in an access node (AN), wherein the AN is used as a secondary node (SN) connected to a primary node (MN) via an X2 or Xn interface in a Long Term Evolution-Dual Connectivity (LTE-DC) or Multiple Radio Access Technology-Dual Connectivity (MR-DC) scenario, the AN including processor circuitry configured such that, during a Conditional Handover (CHO) procedure of a user equipment (UE): the AN receives from the MN a plurality of data forwarding address indication messages, wherein each of the plurality of data forwarding address indication messages contains a data forwarding address corresponding to a candidate target AN; and for each of the plurality of data forwarding address indication messages, when performing early data forwarding toward a bearer terminated by the SN toward the data forwarding address contained in the data forwarding address indication message, the AN provides an early state transition message to the radio interface to be sent to the MN.

[0194] Example 28 includes the method of Example 27, further comprising: sending a fault report message to the MN when no advance data forwarding for a bearer terminated by the SN is performed toward the data forwarding address contained in the data forwarding address indication message.

[0195] Example 29 includes the method described in Example 27, wherein each of the plurality of data forwarding address indication messages further includes a source identifier and a target identifier, the source identifier uniquely identifying the association between the UE and the MN, and the target identifier uniquely identifying the association between the UE and the candidate target AN.

[0196] Example 30 includes the method described in Example 27, wherein the very early state transition message includes a source identifier and a target identifier, the source identifier uniquely identifying the association between the UE and the MN, and the target identifier uniquely identifying the association between the UE and the candidate target AN.

[0197] Example 31 includes the method of Example 27, wherein each of the plurality of data forwarding address indication messages further includes an early data forwarding stop indication to indicate to the SN whether to stop early data forwarding that has been initiated for a portion of a bearer terminated by the SN.

[0198] Example 32 includes the method described in Example 27, wherein, in an MR-DC scenario with a 5G core (5GC), the plurality of data forwarding address indication messages are implemented as XN-UADDRESS INDICATION messages.

[0199] Example 33 includes the method described in Example 27, wherein, in the LTE-DC or MR-DC scenario with Evolved Packet Core (EPC), the plurality of data forwarding address indication messages are implemented as DATA FORWARDING ADDRESSINDICATION messages.

[0200] Example 34 includes the method described in Example 29 or 30, wherein, in an MR-DC scenario with a 5G core (5GC), the source identifier is the source NG-RAN node UE XnAP identifier (ID) and the target identifier is the target NG-RAN node UE XnAPID.

[0201] Example 35 includes the method described in Example 29 or 30, wherein, in the LTE-DC scenario or the MR-DC scenario with an evolved packet core (EPC), the source identifier includes at least one of a source eNB UE X2AP identifier (ID) and a source eNB UE X2AP ID extension, and the target identifier includes at least one of a target eNB UE X2AP ID and a target eNB UE X2AP ID extension.

[0202] Example 36 includes the method of Example 31, further comprising: stopping the advance data forwarding already initiated for a portion of the bearer terminated by the SN when the advance data forwarding stop indication indicates to stop advance data forwarding already initiated for a portion of the bearer terminated by the SN.

[0203] Example 37 includes an access node (AN) comprising: means for performing the method of any one of Examples 19 to 36.

[0204] Example 38 includes an access node (AN) comprising: a memory storing instructions thereon; and processor circuitry coupled to the memory, wherein the instructions, when executed by the processor circuitry, cause the processor circuitry to perform the method of any one of Examples 18 to 36.

[0205] While certain embodiments have been illustrated and described herein for purposes of description, various alternative and / or equivalent embodiments or implementations that achieve the same purpose may be substituted for the illustrated and described embodiments without departing from the scope of the invention. This application is intended to cover any adaptations or variations of the embodiments discussed herein. Therefore, the embodiments described herein are clearly limited only by the appended claims and their equivalents.

Claims

1. An apparatus for use in an access node (AN), wherein, The AN, in Long Term Evolution-Dual Connectivity (LTE-DC) or Multiple Radio Access Technology-Dual Connectivity (MR-DC) scenarios, serves as a master node (MN) connected to a secondary node (SN) via an X2 or Xn interface. The AN includes processor circuitry configured to enable the AN to: During a Conditional Handover (CHO) process of a User Equipment (UE): Multiple data forwarding address indication messages are sent to the SN, wherein each data forwarding address indication message contains a data forwarding address corresponding to a candidate target AN and an early data forwarding stop indication, the early data forwarding stop indication being used to indicate to the SN whether to stop early data forwarding initiated for some SN-terminated bearers; and For each of the plurality of data forwarding address indication messages, receive an early state transition message or a fault report message sent by the SN in response to the data forwarding address indication message.

2. The apparatus of claim 1, wherein, Each of the plurality of data forwarding address indication messages further includes a source identifier and a target identifier, wherein the source identifier uniquely identifies the association between the UE and the MN, and the target identifier uniquely identifies the association between the UE and the candidate target AN.

3. The apparatus of claim 1, wherein, The very early state transition message includes a source identifier and a target identifier. The source identifier uniquely identifies the association between the UE and the MN, and the target identifier uniquely identifies the association between the UE and the candidate target AN.

4. The apparatus of claim 1, wherein, In MR-DC scenarios with 5G core (5GC), the multiple data forwarding address indication messages are implemented as XN-U ADDRESS INDICATION messages.

5. The apparatus of claim 1, wherein, In the LTE-DC scenario or the MR-DC scenario with Evolved Packet Core (EPC), the multiple data forwarding address indication messages are implemented as DATA FORWARDING ADDRESSINDICATION messages.

6. The apparatus as claimed in claim 2 or 3, wherein, In an MR-DC scenario with a 5G core (5GC), the source identifier is the source NG-RAN node UE XnAP identifier (ID), and the target identifier is the target NG-RAN node UE XnAP ID.

7. The apparatus as claimed in claim 2 or 3, wherein, In the LTE-DC scenario or the MR-DC scenario with an evolved packet core (EPC), the source identifier includes at least one of the source eNB UE X2AP identifier (ID) and the source eNB UE X2AP ID extension, and the target identifier includes at least one of the target eNB UE X2AP ID and the target eNB UE X2AP ID extension.

8. An apparatus for use in an access node (AN), wherein, The AN is used as a secondary node (SN) connected to the primary node (MN) via an X2 or Xn interface in Long Term Evolution-Dual Connectivity (LTE-DC) or Multiple Radio Access Technology-Dual Connectivity (MR-DC) scenarios. The AN includes processor circuitry configured to enable the AN to: The MN receives a plurality of data forwarding address indication messages, wherein each of the plurality of data forwarding address indication messages contains a data forwarding address corresponding to a candidate target AN and an early data forwarding stop indication, the early data forwarding stop indication being used to indicate to the SN whether to stop early data forwarding that has been initiated for a portion of the bearer terminated by the SN; For each of the plurality of data forwarding address indication messages, when early data forwarding for a bearer terminated by the SN is performed toward the data forwarding address contained in the data forwarding address indication message, an early state transition message is sent to the MN.

9. The apparatus of claim 8, wherein, The processor circuit is further configured such that the AN: When no advance data forwarding is performed for the bearer terminated by the SN toward the data forwarding address indicated in the data forwarding address indication message, a fault report message is sent to the MN.

10. The apparatus of claim 8, wherein, Each of the plurality of data forwarding address indication messages further includes a source identifier and a target identifier, wherein the source identifier uniquely identifies the association between the UE and the MN, and the target identifier uniquely identifies the association between the UE and the candidate target AN.

11. The apparatus of claim 8, wherein, The very early state transition message includes a source identifier and a target identifier. The source identifier uniquely identifies the association between the UE and the MN, and the target identifier uniquely identifies the association between the UE and the candidate target AN.

12. The apparatus of claim 8, wherein, In MR-DC scenarios with 5G core (5GC), the multiple data forwarding address indication messages are implemented as XN-U ADDRESS INDICATION messages.

13. The apparatus of claim 8, wherein, In the LTE-DC or MR-DC scenario with Evolved Packet Core (EPC), the multiple data forwarding address indication messages are implemented as DATA FORWARDING ADDRESS INDICATION messages.

14. The apparatus of claim 10 or 11, wherein, In an MR-DC scenario with a 5G core (5GC), the source identifier is the source NG-RAN node UE XnAP identifier (ID), and the target identifier is the target NG-RAN node UE XnAP ID.

15. The apparatus of claim 10 or 11, wherein, In the LTE-DC scenario or the MR-DC scenario with an evolved packet core (EPC), the source identifier includes at least one of the source eNB UE X2AP identifier (ID) and the source eNB UE X2AP ID extension, and the target identifier includes at least one of the target eNB UE X2AP ID and the target eNB UE X2AP ID extension.

16. The apparatus of claim 8, wherein, The processor circuit is further configured such that the AN: When the advance data forwarding stop indication indicates to stop advance data forwarding already initiated for a portion of the bearer terminated by the SN, advance data forwarding already initiated for that portion of the bearer terminated by the SN is stopped.

17. A method for use in an access node (AN), wherein, The AN is used as a master node (MN) connected to a secondary node (SN) via an X2 or Xn interface in a Long Term Evolution-Dual Connectivity (LTE-DC) or Multiple Radio Access Technology-Dual Connectivity (MR-DC) scenario, and the method includes: During a Conditional Handover (CHO) procedure for a User Equipment (UE), a plurality of Data Forwarding Address Indication (DIO) messages are provided to the radio interface for transmission to the SN. Each DIO message contains a data forwarding address corresponding to a candidate target AN and an early data forwarding stop indication. The early data forwarding stop indication is used to indicate to the SN whether to stop early data forwarding initiated for bearers terminated by some SNs. For each of the plurality of data forwarding address indication messages, receive an early state transition message or a fault report message sent by the SN in response to the data forwarding address indication message.

18. The method of claim 17, wherein, Each of the plurality of data forwarding address indication messages further includes a source identifier and a target identifier, wherein the source identifier uniquely identifies the association between the UE and the MN, and the target identifier uniquely identifies the association between the UE and the candidate target AN.

19. The method of claim 17, wherein, The very early state transition message includes a source identifier and a target identifier. The source identifier uniquely identifies the association between the UE and the MN, and the target identifier uniquely identifies the association between the UE and the candidate target AN.

20. The method of claim 17, wherein, In MR-DC scenarios with 5G core (5GC), the multiple data forwarding address indication messages are implemented as XN-U ADDRESS INDICATION messages.

21. The method of claim 17, wherein, In the LTE-DC scenario or the MR-DC scenario with Evolved Packet Core (EPC), the multiple data forwarding address indication messages are implemented as DATA FORWARDING ADDRESSINDICATION messages.

22. The method of claim 18 or 19, wherein, In an MR-DC scenario with a 5G core (5GC), the source identifier is the source NG-RAN node UE XnAP identifier (ID), and the target identifier is the target NG-RAN node UE XnAP ID.

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