CN114765826A

CN114765826A - Arrangement in an access node

Info

Publication number: CN114765826A
Application number: CN202210019937.8A
Authority: CN
Inventors: 韩载珉
Original assignee: Intel Corp
Current assignee: Intel Corp
Priority date: 2021-01-11
Filing date: 2022-01-10
Publication date: 2022-07-19

Abstract

The present application relates to AN apparatus for use in AN Access Node (AN) acting as a primary 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 a processor circuit configured to cause the AN, during a Conditional Handover (CHO) procedure of a User Equipment (UE): sending a plurality of data forwarding address indication messages to the SN, wherein each data forwarding address indication message in the plurality of data forwarding address indication messages contains a data forwarding address corresponding to the candidate target AN; and for each of the plurality of data forwarding address indication messages, receiving an extremely early state transfer message or a failure report message sent by the SN in response to the data forwarding address indication message.

Description

Arrangement in an access node

Priority requirement

This application is based on and claims priority from U.S. patent application No. 63/135,939, filed on 11/1/2021, which is hereby incorporated by reference in its entirety.

Technical Field

Embodiments of the present disclosure relate generally to the field of wireless communications, and more particularly, to AN apparatus for use in AN Access Node (AN).

Background

Mobile communications have evolved from early speech systems to today's highly sophisticated integrated communication platforms. A 5G or New Radio (NR) wireless communication system will provide access to information and sharing of data by various users and applications anywhere and at anytime and will coexist in the long term with a 4G or Long Term Evolution (LTE) wireless communication system.

Drawings

Embodiments of the present disclosure are illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings in which like reference numerals refer to similar elements.

Fig. 1 shows an example signaling flow for a MN to ng-eNB/gNB change procedure in an MR-DC scenario with 5 GC.

Fig. 2A illustrates a flow diagram of a method for use in AN Access Node (AN) that functions as a MN connected to a SN via AN X2 or Xn interface in AN LTE-DC or MR-DC scenario, in accordance with some embodiments of the present disclosure.

Fig. 2B illustrates a flow diagram of a method for use in AN Access Node (AN) that serves as AN SN for connection with a MN via AN X2 or Xn interface in AN LTE-DC or MR-DC scenario, in accordance with some embodiments of the present disclosure.

Fig. 3 shows an example signaling flow for a MN-to-eNB change procedure in an MR-DC scenario with EPC.

Fig. 4 shows an example signaling flow for MeNB to eNB change procedure in LTE-DC scenarios.

Fig. 5 shows an example signaling flow for a MN to ng-eNB/gNB change procedure in an MR-DC scenario with 5 GC.

Fig. 6 shows a schematic diagram of a network according to various embodiments of the present disclosure.

Fig. 7 shows a schematic diagram of a wireless network in accordance with various embodiments of the present disclosure.

Fig. 8 illustrates a block diagram of 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 methodologies discussed herein, according to some example embodiments of the present disclosure.

Detailed Description

Various aspects of the illustrative embodiments will be described using terms commonly employed by those skilled in the art to convey the substance of the disclosure to others skilled in the art. It will be apparent, however, to one skilled in the art that many alternative embodiments may be practiced using portions of the described aspects. For purposes of explanation, specific numbers, materials, and configurations are set forth in order to provide a thorough understanding of the illustrative embodiments. It will be apparent, however, to one skilled in the art that alternative embodiments may be practiced without these specific details. In other instances, well-known features may be omitted or simplified in order not to obscure the illustrative embodiments.

Further, various operations will be described as multiple discrete operations, in turn, in a manner that is most helpful in understanding the illustrative embodiments; however, the order of description should not be construed as to imply that these operations are necessarily order dependent. In particular, these operations need not be performed in the order of presentation.

The phrases "in an embodiment," "in one embodiment," and "in some embodiments" are used repeatedly herein. Such phrases are not generally referring to the same embodiment; however, they may also refer to the same embodiment. The terms "comprising," "having," and "including" are synonymous, unless the context dictates otherwise. The phrases "A or B" and "A/B" mean "(A), (B), or (A and B)".

Conditional Handover (CHO) of a User Equipment (UE) may be supported in a Dual Connectivity (DC) scenario including an LTE dual connectivity (LTE-DC) scenario and a multi-radio access technology dual connectivity (MR-DC) scenario. For example, in a MR-DC scenario with a 5G core (5GC), when a UE is conditionally handed over from a source primary node (S-MN) to a target next generation evolved node B (ng-eNB)/next generation node B (gNB), a MN-to-ng-eNB/gNB change procedure may be used to transfer UE context data from the S-MN to the target ng-eNB/gNB, where the S-MN and the target ng-eNB/gNB may belong to the same radio access technology (i.e., they are both ng-eNB or both gNB) or to different radio access technologies.

Fig. 1 shows an example signaling flow for a MN to ng-eNB/gNB change procedure in an MR-DC scenario with 5 GC. As shown in fig. 1, the MN-to-ng-eNB/gNB change procedure includes:

s102, the S-MN sends a switching request message to the target ng-eNB/gNB to initiate an Xn switching preparation process.

Note 1: prior to step S102, the S-MN may trigger a MN-initiated Secondary Node (SN) modification procedure to retrieve a Secondary Cell Group (SCG) configuration of the source secondary node (S-SN) and to allow data forwarding related information to be provided to the S-SN.

S104, the target ng-eNB/gNB sends a switching request confirmation message to the S-MN, wherein the switching request confirmation message comprises a field indicating the release of the SCG configuration of the S-SN. The target ng-eNB/gNB may also provide a data forwarding address to the S-MN via a handover request acknowledgement message if early data forwarding is required for the SN terminated bearer (SN-terminated bearer) (i.e., the data forwarding address corresponding to the target ng-eNB/gNB may be included in the handover request acknowledgement message).

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 comprises a reason indicating a Master Cell Group (MCG) mobility.

S106b, the S-SN sends a SN release request acknowledge message to the S-MN. Reception of the SN release request message triggers the S-SN to stop providing user data to the UE and, if applicable, to start normal forwarding of data to the target ng-eNB/gNB.

S106c, if the advanced data forwarding of the SN terminated load bearing is needed, the S-MN sends an Xn-U address indication message to the S-SN, wherein the Xn-U address indication message comprises a data forwarding address corresponding to the target ng-eNB/gNB.

Note 1 a: in the case of CHO of the UE, steps S106a and S106b are performed after the S-MN receives an indication that the UE has successfully accessed the target ng-eNB/gNB (i.e., after step S112).

Note 1 b: in case of CHO of the UE, step S106c is performed immediately after step S104. The Xn-U address indication message is used by the S-MN to inform the S-SN of the CHO of the UE and to provide the S-SN with the data forwarding address corresponding to the target ng-eNB/gNB, and then the S-SN can perform early data forwarding for the SN terminated bearer towards the data forwarding address corresponding to the target ng-eNB/gNB and send an extremely early state transfer message to the S-MN. If applicable, the S-SN may perform normal data forwarding to the target ng-eNB/gNB upon receiving the SN release request message from the S-MN and send an SN status transfer message to the S-MN. In case the Xn-U address indication message is rejected by the S-SN, the S-MN can resend the message after step S106 b.

When the S-MN decides to perform CHO of the UE, it does not release SCG configuration of S-SN immediately after CHO preparation. Instead, the S-MN sends an Xn-U address indication message to the S-SN to provide the S-SN with a data forwarding address corresponding to the target ng-eNB/gNB and informs the S-SN of the UE' S CHO so that the S-SN can perform early data forwarding for SN terminated bearers. The S-SN sends an extremely early state transfer message to the S-MN if early data forwarding for SN terminated bearers is performed.

In principle, the S-MN may prepare multiple candidate target nodes for the CHO of the UE (e.g., candidate cell 1 with target gNB 1 and candidate cell 2 with target gNB 2), and the data forwarding addresses of the different target nodes will be different. Currently, however, the S-MN cannot provide these different data forwarding addresses to the S-SN. There can only be one Xn-U address indication message for early data forwarding from the S-SN, which essentially limits early data forwarding to only one candidate target node of the plurality of candidate target nodes. Such a restriction essentially supports only early data forwarding for one candidate target node or only late data forwarding for other candidate target nodes than the one candidate target node.

In addition, when the CHO of the UE is modified or cancelled, the early data forwarding already initiated for all or part of the SN terminated bearers should also be cancelled accordingly. However, at present in both the LTE-DC scenario and the MR-DC scenario, early data forwarding already initiated for any SN terminated bearer is not possible to cancel because the S-MN simply throws out the data forwarding address for early data forwarding of the SN terminated bearer through 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.

Thus, the present disclosure proposes a solution that overcomes the above limitations and/or is able to cancel early data forwarding that has been initiated for certain SN terminated bearers if the CHO of the UE is modified or cancelled.

Fig. 2A illustrates a flow diagram of a method 200A for use in AN Access Node (AN) that functions as a MN connected to a SN via AN X2 or Xn interface in AN LTE-DC or MR-DC scenario, in accordance with some embodiments of the present disclosure. As shown in fig. 2A, method 200A includes: S202A, during a CHO procedure 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 data forwarding address indication message of the plurality of data forwarding address indication messages, receiving an extremely early state transition message or a failure report message sent by the SN in response to the data forwarding address indication message.

Fig. 2B illustrates a flow diagram of a method 200B for use in AN Access Node (AN) that serves as a SN connected to a MN via AN X2 or Xn interface in AN LTE-DC or MR-DC scenario, in accordance with some embodiments of the present disclosure. As shown in fig. 2B, the method 200B includes: S202B, during a CHO procedure of the UE, receiving a plurality of data forwarding address indication messages from the MN, 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; S204B, for each of the plurality of data forwarding address indication messages, sending an extremely early state transition message to the MN when performing early data forwarding for the SN terminated bearer towards the data forwarding address contained in the data forwarding address indication message; S206B, for each of the plurality of data forwarding address indication messages, sending a failure report message to the MN when early data forwarding for the SN terminated bearer is not performed towards the data forwarding address contained in the data forwarding address indication message.

With method 200A and/or method 200B, the above limitations may be alleviated by allowing multiple operations for communicating data forwarding address indication messages and very early state transfer messages between MNs and SNs for different candidate target nodes.

In some embodiments, the data forwarding address indication message may further 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.

In some embodiments, the data forwarding address indication message may also contain an early data forwarding stop indication to indicate to the SNs whether to stop early data forwarding that has been initiated for certain SN terminated bearers. In this case, the method 200B may further include: and when the early data forwarding stopping indication indicates that the early data forwarding initiated by the bearer terminated by the partial SN is stopped, stopping the early data forwarding initiated by the bearer terminated by the partial SN.

The implementation of the method 200A and the method 200B in the LTE-DC scenario and the MR-DC scenario will be described below.

Method 200A and method 200B in LTE-DC scenarios or MR-DC scenarios with Evolved Packet Core (EPC) Implementation of

In an LTE-DC scenario or an MR-DC scenario with EPC, the plurality of DATA FORWARDING ADDRESS INDICATION messages may be implemented as DATA forward ADDRESS INDICATION messages, the source identifier may include at least one of a source eNB UE X2AP Identification (ID) and a source eNB UE X2AP ID extension, and the target identifier may include at least one of a target eNB UE X2AP ID and a target eNB UE X2AP ID extension.

In AN LTE-DC scenario or AN MR-DC scenario with EPC, DATA Forward Address information messages are used during CHO of the UE to provide DATA FORWARDING addresses corresponding to different candidate target ANs to the source secondary eNB/en-gNB (S-SeNB/en-gNB).

In an LTE-DC scenario or an MR-DC scenario with EPC, a COUNT (COUNT) value related to a forwarded downlink Service Data Unit (SDU) is transferred from the S-SeNB/en-gNB to a source master eNB (S-MeNB) during CHO of the UE using an extremely early state transfer message.

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

TABLE 1 DATA FORWARDING ADDRESS INDICATION

Interval(s)	Description of the invention
		maxnoofBearers	The maximum number value of the E-RAB is 256.

TABLE 2 very early State transitions

Fig. 3 shows an example signaling flow for a MN-to-eNB change procedure in an MR-DC scenario with EPC. The MN-to-eNB change procedure may be used to transfer UE context data from the S-MN/SN to the target eNB. The MN-to-eNB change process comprises the following steps:

s302, the S-MN sends a handover request message to the target eNB to initiate an X2 handover preparation procedure, wherein the handover request message may include both SCG configuration of the S-SN and MCG configuration of the S-MN.

Note 1: before step S302, the S-MN may trigger a MN-initiated SN modification procedure to retrieve the SCG configuration of the S-SN.

S304, the target eNB sends a switching request confirmation message to the S-MN, wherein the switching request confirmation message can comprise a field indicating the release of the SCG configuration of the S-SN and can also comprise a data forwarding address corresponding to the target eNB if advanced data forwarding needs to be carried out on the SN terminated bearer.

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

S306b, the S-SN sends a SgNB release request acknowledgement message to the S-MN. The reception of the SgNB release request message triggers the S-SN to stop providing user data to the UE and, if applicable, to start normal data forwarding.

Note 1 a: in the case of CHO of the UE, steps S306a and S306b are performed after the S-MN receives an indication that the UE has successfully accessed the target eNB (i.e., after step S312).

Note 1 b: in case of CHO by the UE, a plurality of data forwarding address indication messages may be sent from the S-MN to the S-SN immediately after step S304, if early data forwarding for SN terminated bearers is required. The data forwarding address indication message is used to inform the S-SN of the CHO of the UE and provide the S-SN with data forwarding addresses corresponding to different candidate target ANs, and then the S-SN may perform early data forwarding for SN terminated bearers towards the data forwarding addresses corresponding to the different candidate target ANs and send AN extremely early state transfer message to the S-MN. A source/target UE X2AP ID pair may be included in each data forwarding address indication message and may be identified by the source/target UE X2AP ID pair in a plurality of data forwarding address indication messages. Source/target UE X2AP ID pairs may also be included in each very early state transition message and may be identified by the source/target UE X2AP ID pairs in the very early state transition message sent in response to the multiple data forwarding address indication messages. Based on the source/target UE X2AP ID pair contained in the data forwarding address indication message and the very early state transition message, a correspondence between the data forwarding address indication message and the very early state transition message may be determined. The data forwarding address indication message may also contain an early data forwarding stop indication to indicate that the S-SNs stop early data forwarding already initiated for some SN terminated bearers (if they no longer need to do early data forwarding due to modification or cancellation of the CHO by the UE). If applicable, once the S-SN receives the SgNB release request message (performed after step S312), the S-SN can perform normal data forwarding and send an SN status transfer message to the S-MN.

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

S310-S312, the UE synchronizes to the target eNB.

S314a-S314b, for SN terminated bearers using radio Link control acknowledged mode (RLC AM), the S-SN sends an SN status transfer message to the S-MN, which then sends an SN status transfer message to the target eNB.

S316, if applicable, normal data forwarding is performed from the S-SN.

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

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

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

S320-S328, the target eNB initiates S1 a path switching process.

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

S332, upon receiving the UE context release message, the S-MN releases radio and control plane related resources associated with the UE context data. Any ongoing data forwarding may continue.

Note 3: the MN-to-eNB change procedure described above may also be used for inter-system handover of a UE from an eNB to a ng-eNB/gNB.

Fig. 4 shows an example signaling flow for MeNB to eNB change procedure in LTE-DC scenarios. The MeNB to eNB change procedure may be used to transfer UE context data from a source master eNB/secondary eNB (S-MeNB/SeNB) to a target eNB. The MeNB-to-eNB change procedure includes:

s402, the S-MeNB sends a handover request message to the target eNB to initiate an X2 handover preparation procedure, wherein the handover request message may include the SCG configuration of the S-SeNB.

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

S406, if the resource allocation of the target eNB is successful, the S-MeNB sends an SeNB release request message to the S-SeNB to initiate the resource release of the S-SeNB. Reception of the SeNB release request message triggers the S-SeNB to stop providing user data to the UE and, if applicable, to start normal data forwarding.

Note 1: in the case of CHO by the UE, step S406 is performed after the S-MeNB receives an indication that the UE has successfully accessed the target eNB (i.e., after step S412).

Note 2: in case of CHO by the UE, a plurality of data forwarding address indication messages may be sent from the S-MeNB to the S-SeNB immediately after step S404, if early data forwarding for SN terminated bearers is required. The data forwarding address indication message is used to inform the S-SeNB of the CHO of the UE and provide the S-SeNB with data forwarding addresses corresponding to different candidate target ANs, and then the S-SeNB may perform early data forwarding for SN terminated bearers towards the data forwarding addresses corresponding to the different candidate target ANs and send AN extremely early state transfer message to the S-MeNB. A source/target UE X2AP ID pair may be included in each data forwarding address indication message and may be identified by the source/target UE X2AP ID pair in a plurality of data forwarding address indication messages. A source/target UE X2AP ID pair may also be included in each very early state transition message and may be identified by the source/target UE X2AP ID pair in the very early state transition message sent in response to the multiple data forwarding address indication messages. Based on the source/target UE X2AP ID pair contained in the data forwarding address indication message and the very early state transition message, a correspondence between the data forwarding address indication message and the very early state transition message may be determined. The data forwarding address indication message may also contain an early data forwarding stop indication to indicate that the S-SNs stop early data forwarding already initiated for some SN terminated bearers (if they no longer need to do early data forwarding due to modification or cancellation of the CHO by the UE). If applicable, once the S-SeNB receives the SgNB release request message (performed after step S412), the S-SeNB may perform normal data forwarding and send an SN status transfer message to the S-MeNB.

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

S410-S412, the UE synchronizes to the target eNB.

S414a-S416, normal data forwarding from the S-SeNB, if applicable. It may start as early as when the S-SeNB receives the SeNB release request message from the S-MeNB.

S418-S426, the target eNB initiates S1 a path switch procedure.

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

Upon receiving the UE context release message, the S-SeNB may release radio and control plane related resources associated with the UE context data S430. Any ongoing data forwarding may continue.

Implementation of method 200A and method 200B in MR-DC and 5GC scenarios

In a MR-DC scenario with 5GC, the multiple data-forwarding ADDRESS INDICATION messages may be implemented as XN-U ADDRESS INDICATION messages, the source identifier may be a source NG-RAN node UE XnAP Identity (ID), and the target identifier may be a target NG-RAN node UE XnAP ID.

In an MR-DC scenario with 5GC, an XN-U ADDRESS INDICATION message may be used to provide data forwarding or Xn-U bearer addresses from the S-MN to the S-SN.

In an MR-DC scenario with 5GC, the count value related to the forwarded downlink Service Data Units (SDUs) is transferred from the S-SN to the S-MN using an extremely early state transfer message during CHO of the UE.

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

TABLE 3 XN-U ADDRESS INDICATION

Interval(s)	Description of the invention
		maxnoofPDUSsessions	The maximum number value of a PDU session is 256.

Condition	Description of the invention
		If CHOMRDC indicator is true	If the CHO MR DC indicator IE is present and set to "true", then this IE should be present.

TABLE 4 very early State transitions

Interval(s)	Description of the invention
		maxnoofDRBs	The maximum number value of DRBs allowed to be forwarded to one UE is 32.

Fig. 5 shows an example signaling flow for a MN to ng-eNB/gNB change procedure in an MR-DC scenario with 5 GC. The MN-to-ng-eNB/gNB change procedure may 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 may belong to the same radio access technology (i.e., they are both ng-eNBs or both gNBs) or to different radio access technologies. As shown in fig. 5, the MN-to-ng-eNB/gNB change procedure includes:

s502, the S-MN sends a handover request message to the target ng-eNB/gNB to initiate an Xn handover preparation process, wherein the handover request message may include SCG configuration of the S-SN and MCG configuration of the S-MN.

Note 1: prior to step S502, the S-MN may trigger a MN-initiated SN modification procedure to retrieve the SCG configuration of the S-SN and to allow data forwarding related information to be provided to the S-SN.

S504, the target ng-eNB/gNB sends a handover request confirmation message to the S-MN, wherein the handover request confirmation message may include a field indicating release of SCG configuration of the S-SN, and may further include a data forwarding address corresponding to the target ng-eNB/gNB if advanced data forwarding for the SN-terminated bearer is required.

S506a, 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 may include a reason indicating MCG mobility.

At S506b, the S-SN sends a SN release request acknowledge message to the S-MN. The reception of the SN release request message triggers the S-SN to stop providing user data to the UE and, if applicable, to start normal data forwarding.

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

Note 1 a: in the case of CHO of the UE, steps S506a and S506b are performed after the S-MN receives an indication that the UE has successfully accessed the target ng-eNB/gNB (i.e., after step S512).

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

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

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

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

S516, if applicable, normal data forwarding is carried out from the S-SN.

S518a, the S-SN sends a secondary RAT data usage report message to the S-MN, wherein the secondary RAT data usage report message includes information about the amount of data delivered to and received from the UE over NR radio resources for the relevant E-RAB.

Note 2: the order in which the S-SN transmits the supplementary RAT data usage report message and performs normal data forwarding is not limited. The S-SN may send a secondary RAT data usage report message when transmission of a related quality of service (QoS) flow stops.

S518b, the S-MN sends a supplementary RAT report message to an Authentication Management Function (AMF) entity to provide information on NR/E-UTRA resources used to carry data delivered to and received from the UE.

S520-S528, the target ng-eNB/gNB initiates a path switching process.

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

S532, the S-SN releases radio and control plane related resources associated with the UE context data upon receiving the UE context release message from the S-MN. Any ongoing data forwarding may continue.

Note 3: the MN to ng-eNB/gNB change procedure described above may be used for inter-system handover of a UE from ng-eNB/gNB to an eNB.

Fig. 6-7 illustrate various systems, devices, and components that can implement aspects of the disclosed embodiments.

Fig. 6 shows a schematic diagram of a network 600 according to various embodiments of the present disclosure. The network 600 may operate in accordance with 3GPP technical specifications for Long Term Evolution (LTE) or 5G/NR systems. However, the exemplary embodiments are not limited in this respect and the described embodiments may be applied to other networks, such as future 3GPP systems and the like, which benefit from the principles described herein.

Network 600 may include a UE 602, which may include any mobile or non-mobile computing device designed to communicate with a Radio Access Network (RAN)604 via an over-the-air connection. The UE 602 may be, but is not limited to, a smartphone, a tablet computer, a wearable computer device, a desktop computer, a laptop computer, an in-vehicle infotainment device, an in-vehicle entertainment device, a dashboard, a heads-up display device, an in-vehicle diagnostic device, a dashboard mobile device, a mobile data terminal, an electronic engine management system, an electronic/engine control unit, an electronic/engine control module, an embedded system, a sensor, a microcontroller, a control module, an engine management system, a network device, a machine-to-machine communication device, a machine-to-machine (M2M) or device-to-device (D2D) device, an internet of things (IoT) device, and/or the like.

In some embodiments, network 600 may include multiple UEs directly coupled to each other through sidelink interfaces. The UE may be an M2M/D2D device that communicates using a physical secondary link channel (e.g., without limitation, a physical secondary link broadcast channel (PSBCH), a physical secondary link discovery channel (PSDCH), a physical secondary link shared channel (PSSCH), a physical secondary link control channel (PSCCH), a physical secondary link fundamental channel (PSFCH), etc.).

In some embodiments, the UE 602 may also communicate with an Access Point (AP)606 over an over-the-air connection. The AP 606 may manage Wireless Local Area Network (WLAN) connections, which may be used to offload some/all network traffic from the RAN 604. The connection between the UE 602 and the AP 606 may be consistent with any IEEE 802.11 protocol, where the AP 606 may be wireless fidelity

A router. In some embodiments, the 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 configuring, by the RAN 604, the UE 602 to utilize both cellular radio resources and WLAN resources.

The RAN 604 may include one or more access nodes, e.g., AN Access Node (AN) 608. AN 608 may terminate the air interface protocols of UE 602 by providing access stratum protocols including a Radio Resource Control (RRC) protocol, a Packet Data Convergence Protocol (PDCP), a Radio Link Control (RLC) protocol, a Medium Access Control (MAC) protocol, and AN L1 protocol. In this manner, the AN 608 may enable a data/voice connection between the Core Network (CN)620 and the UE 602. In some embodiments, AN 608 may be implemented in a discrete device or as one or more software entities running on a server computer (a virtual network may be referred to as a distributed ran (cran) or virtual baseband unit pool, as part of a virtual network, for example). 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), and so on. The AN 608 may be a macrocell base station or a low power base station that provides a microcell, picocell, or other similar cell with a smaller coverage area, smaller user capacity, or higher bandwidth than a macrocell.

In embodiments where the RAN 604 comprises multiple ANs, they may be coupled to each other through AN X2 interface (if the RAN 604 is AN LTE RAN) or AN Xn interface (if the RAN 604 is a 5G RAN). In some embodiments, the X2/Xn interface, which may be separated into a control/user plane interface, may allow the AN to communicate information related to handover, data/context transfer, mobility, load management, interference coordination, etc.

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

The RAN 604 may provide an air interface over a licensed spectrum or an unlicensed spectrum. To operate in unlicensed spectrum, the node may use a License Assisted Access (LAA), enhanced LAA (elaa), and/or further enhanced LAA (felaa) mechanism based on the Carrier Aggregation (CA) technique of PCell/Scell. Prior to accessing the unlicensed spectrum, the node may perform a media/carrier sensing operation based on, for example, a Listen Before Talk (LBT) protocol.

In a vehicle-to-all (V2X) scenario, the UE 602 or AN 608 may be or act as a roadside unit (RSU), which may refer to any transport infrastructure entity for V2X communications. The RSU may be implemented in or by AN appropriate AN or stationary (or relatively stationary) UE. An RSU implemented in or by a UE may be referred to as a "UE-type RSU"; an RSU implemented in or by an eNB may be referred to as an "eNB-type RSU"; RSUs implemented in the next generation nodeb (gNB) or implemented by the gNB may be referred to as "gNB-type RSUs" or the like. In one example, the RSU is a computing device coupled with radio frequency circuitry located at the curb side that provides connection 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 may provide very low latency communications required for high speed events (e.g., collision avoidance, traffic warnings, etc.). Additionally or alternatively, the RSU may provide other cellular/WLAN communication services. The components of the RSU may be enclosed in a weatherproof enclosure suitable for outdoor installation and may include a network interface controller to provide a wired connection (e.g., ethernet) to a traffic signal controller or backhaul network.

In some embodiments, RAN 604 may be an LTE RAN 610 including an evolved node b (eNB), e.g., eNB 612. The LTE RAN 610 may provide an LTE air interface with the following features: subcarrier spacing (SCS) of 15 kHz; 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 signals (CSI-RS) for CSI acquisition and beam management; relying on a Physical Downlink Shared Channel (PDSCH)/Physical Downlink Control Channel (PDCCH) demodulation reference signal (DMRS) for PDSCH/PDCCH demodulation; and relying on Cell Reference Signals (CRS) for cell search and initial acquisition, channel quality measurements, and channel estimation, and on channel estimation for coherent demodulation/detection at the UE. The LTE air interface may operate on the 6GHz sub-band.

In some embodiments, RAN 604 may be a Next Generation (NG) -RAN 614 having a gNB (e.g., gNB 616) or a gn-eNB (e.g., NG-eNB 618). The gNB 616 may connect with 5G-enabled UEs using a 5G NR interface. The gNB 616 may connect with the 5G core through an NG interface, which may include an N2 interface or an N3 interface. The NG-eNB 618 may also be connected with the 5G core over the NG interface, but may be connected with the UE over the LTE air interface. The gNB 616 and ng-eNB 618 may be connected to each other over an Xn interface.

In some embodiments, the NG interface may be divided into two parts, a NG user plane (NG-U) interface, which carries traffic data between the UPF 648 and the nodes of the NG-RAN 614 (e.g., the N3 interface), and a NG control plane (NG-C) interface, which is a signaling interface between the access and mobility management function (AMF)644 and the nodes of the NG-RAN 614 (e.g., the N2 interface).

NG-RAN 614 may 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 a low density parity check code (LDPC) for the data. The 5G-NR air interface may rely on channel state reference signals (CSI-RS), 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 may use Physical Broadcast Channel (PBCH) demodulation reference signals (DMRS) for PBCH demodulation; performing phase tracking of the PDSCH using a Phase Tracking Reference Signal (PTRS); and time tracking using the tracking reference signal. The 5G-NR air interface may operate over the FR1 frequency band, which includes the 6GHz sub-band, or the FR2 frequency band, which includes the 24.25GHz to 52.6GHz frequency band. The 5G-NR air interface may include synchronization signals and PBCH blocks (SSBs), which are regions of a downlink resource grid including Primary Synchronization Signals (PSS)/Secondary Synchronization Signals (SSS)/PBCH.

In some embodiments, the 5G-NR air interface may use a bandwidth portion (BWP) for various purposes. For example, BWP may be used for dynamic adaptation of SCS. For example, the UE 602 may be configured with multiple BWPs, where each BWP configuration has a different SCS. When the BWP is indicated to the UE 602 to change, the SCS of the transmission also changes. Another use case for BWP is related to power saving. In particular, the UE 602 may be configured with multiple BWPs with different numbers of frequency resources (e.g., PRBs) to support data transmission in different traffic load scenarios. BWPs containing a smaller number of PRBs may be used for data transmission with smaller traffic load while allowing power savings at UE 602 and, in some cases, at gNB 616. BWPs containing a large number of PRBs may be used in scenarios with higher traffic loads.

The RAN 604 is communicatively coupled to a CN 620, which includes network elements, to provide various functions to support data and telecommunications services to customers/subscribers (e.g., users of the UE 602). The components of the CN 620 may be implemented in one physical node or in different physical nodes. In some embodiments, Network Function Virtualization (NFV) may be used to virtualize any or all functions provided by the network elements of the CN 620 onto physical computing/storage resources in servers, switches, and the like. The logical instances of the CN 620 may be referred to as network slices, and the logical instances of a portion of the CN 620 may be referred to as network subslices.

In some embodiments, the CN 620 may be an LTE CN 622, which may also be referred to as an EPC. LTE CN 622 may include Mobility Management Entity (MME)624, Serving Gateway (SGW)626, serving General Packet Radio Service (GPRS) support node (SGSN)628, Home Subscriber Server (HSS)630, Proxy Gateway (PGW)632, and policy control and charging rules function (PCRF)634, which are coupled to each other by an interface (or "reference point") as shown. The functionality of the elements of LTE CN 622 may be briefly introduced as follows.

The MME 624 may implement mobility management functions to track the current location of the UE 602 to facilitate paging, bearer activation/deactivation, handover, gateway selection, authentication, etc.

The SGW 626 may terminate the S1 interface towards the RAN and route data packets between the RAN and the LTE CN 622. SGW 626 may be a local mobility anchor for inter-RAN node handovers and may also provide an anchor for inter-3 GPP mobility. Other responsibilities may include lawful interception, billing, and some policy enforcement.

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

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

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

PCRF 634 is the policy and charging control element of LTE CN 622. PCRF 634 may be communicatively coupled to application/content server 638 to determine appropriate quality of service (QoS) and charging parameters for a service flow. The PCRF 632 may provide the relevant rules to the PCEF (via the Gx reference point) with the appropriate Traffic Flow Template (TFT) and QoS Class Identifier (QCI).

In some embodiments, the CN 620 may be a 5G core network (5GC) 640. The 5GC 640 may include an authentication server function (AUSF)642, an access and mobility management function (AMF)644, a Session Management Function (SMF)646, a User Plane Function (UPF)648, a Network Slice Selection Function (NSSF)650, a network open function (NEF)652, an NF storage function (NRF)654, a Policy Control Function (PCF)656, a Unified Data Management (UDM)658, and an Application Function (AF)660, which are coupled to each other by interfaces (or "reference points") as shown. The functions of the elements of the 5GC 640 may be briefly described as follows.

The AUSF 642 may store data for authentication of the UE 602 and handle authentication related functions. The AUSF 642 may facilitate a common authentication framework for various access types. The AUSF 642 may also expose a Nausf service based interface in addition to communicating with other elements of the 5GC 640 through reference points as shown.

The AMF 644 may allow other functions of the 5GC 640 to communicate with the UE 602 and the RAN 604 and subscribe to notifications of mobility events for the UE 602. The AMF 644 may be responsible for registration management (e.g., registering the UE 602), connection management, reachability management, mobility management, lawful interception of AMF-related events, and access authentication and authorization. AMF 644 may provide for the transmission of Session Management (SM) messages between UE 602 and SMF646, and act as a transparent proxy for routing SM messages. The AMF 644 may also provide for the transmission of SMS messages between the UE 602 and the SMSF. The AMF 644 may interact with the AUSF 642 and the UE 602 to perform various security anchoring and context management functions. Further, AMF 644 may be a termination point of the RAN CP interface, which may include or be an N2 reference point between RAN 604 and AMF 644; the AMF 644 may act as a termination point for NAS (N1) signaling and perform NAS ciphering and integrity protection. The AMF 644 may also support NAS signaling with the UE 602 over the N3 IWF interface.

SMF646 may be responsible for SM (e.g., tunnel management between UPF 648 and AN 608, session establishment); UE IP address assignment and management (including optional authorization); selection and control of the UP function; configuring flow control at the UPF 648 to route the flow to the appropriate destination; termination of the interface to the policy control function; controlling a portion of policy enforcement, charging, and QoS; lawful interception (for SM events and interface to the LI system); terminate the SM portion of the NAS message; a downlink data notification; initiating AN-specific SM message (sent to AN 608 over N2 through AMF 644); and determining an SSC pattern for the session. SM may refer to management of PDU sessions, and a PDU session or "session" may refer to a PDU connection service that provides or enables exchange of PDUs between the UE 602 and the data network 636.

The UPF 648 may serve as an anchor point for intra-RAT and inter-RAT mobility, an external PDU session point interconnected with the data network 636, and a branch point to support multi-homed PDU sessions. The UPF 648 may also perform packet routing and forwarding, perform packet inspection, perform the user plane part of policy rules, lawful intercepted packets (UP collection), perform traffic usage reporting, perform QoS processing for the user plane (e.g., packet filtering, gating, UL/DL rate enforcement), perform uplink traffic validation (e.g., SDF to QoS flow mapping), transport level packet marking in uplink and downlink, and perform downlink packet buffering and downlink data notification triggering. The UPF 648 may include an uplink classifier to support routing traffic flows to the data network.

The NSSF 650 may select a set of network slice instances that serve the UE 602. NSSF 650 may also determine allowed Network Slice Selection Assistance Information (NSSAI) and mapping to a single NSSAI (S-NSSAI) of the subscription, if desired. The NSSF 650 may also determine a set of AMFs to use for serving the UE 602, or determine a list of candidate AMFs, based on a suitable configuration and possibly by querying the NRF 654. The selection of a set of network slice instances for the UE 602 may be triggered by the AMF 644 (to which the UE 602 registers by interacting with the NSSF 650), which may result in a change in the AMF. NSSF 650 may interact with AMF 644 via the N22 reference point; and may communicate with another NSSF in the visited network via an N31 reference point (not shown). Further, NSSF 650 may expose an interface based on the NSSF service.

NEF 652 may securely expose services and capabilities provided by 3GPP network functions for third parties, internal exposure/re-exposure, AF (e.g., AF 660), edge computing or fog computing systems, and the like. In these embodiments, NEF 652 may authenticate, authorize, or restrict AF. NEF 652 may also translate information exchanged with AF 660 and information exchanged with internal network functions. For example, the NEF 652 may convert between an AF service identifier and internal 5GC information. NEF 652 may also receive information from other NFs based on the public capabilities of the other NFs. This information may be stored as structured data at NEF 652 or at data store NF using a standardized interface. NEF 652 may then re-expose the stored information to other NFs and AFs, or for other purposes such as analysis. In addition, NEF 652 may expose an interface based on the Nnef service.

NRF 654 may support a service discovery function, receive NF discovery requests from NF instances, and provide information of discovered NF instances to NF instances. NRF 654 also maintains information of available NF instances and the services that it supports. As used herein, the terms "instantiate," "instance," and the like may refer to creating an instance, "instance" may refer to a specific occurrence of an object, which may occur, for example, during execution of program code. Further, NRF 654 may expose an interface based on the nrrf service.

PCF 656 may provide policy rules to control plane functions to enforce these policy rules and may also support a unified policy framework to manage network behavior. The PCF 656 may 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 through reference points as shown, the PCF 656 also exposes an Npcf service-based interface.

UDM 658 may process subscription-related information to support network entities in handling communication sessions and may store subscription data for UE 602. For example, subscription data may be communicated via an N8 reference point between UDM 658 and AMF 644. UDM 658 can include two parts: application front end and User Data Record (UDR). The UDR may store policy data and subscription data for UDMs 658 and PCF 656 and/or structured data and application data for exposure for NEF 652 (including PFD for application detection, application request information for multiple UEs 602). UDR 221 may expose a Nudr service-based interface to allow UDM 658, PCF 656, and NEF 652 to access a particular set of stored data, as well as read, update (e.g., add, modify), delete, and subscribe to notifications of relevant data changes in the UDR. The UDM may include a UDM-FE (UDM front end) that is responsible for handling credentials, location management, subscription management, and the like. Several different front ends may serve 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. UDM 658 may expose a numm service based interface in addition to communicating with other NFs through reference points as shown.

AF 660 may provide application impact on traffic routing, provide access to NEF, and interact with policy framework for policy control.

In some embodiments, the 5GC 640 may enable edge computing by selecting operator/third party services that are geographically close to the point at which the UE 602 connects to the network. This may reduce delay and load on the network. To provide an edge computation implementation, the 5GC 640 may select the UPF 648 near the UE 602 and perform traffic steering from the UPF 648 to the data network 636 over an N6 interface. This may be based on UE subscription data, UE location, and information provided by AF 660. In this way, the AF 660 can affect UPF (re) selection and traffic routing. Based on operator deployment, the network operator may allow AF 660 to interact directly with the relevant NFs when AF 660 is considered a trusted entity. In addition, AF 660 may expose a Naf service based interface.

The data network 636 may represent various network operator services, internet access, or third party services that may be provided by one or more servers, including, for example, an application/content server 638.

Fig. 7 schematically illustrates a wireless network 700 in accordance with various embodiments. The wireless network 700 may include a UE 702 in wireless communication with AN 704. The UE 702 and the AN 704 may be similar to and substantially interchangeable with like-named components described elsewhere herein.

The UE 702 may be communicatively coupled with the AN 704 via a connection 706. Connection 706 is shown as an air interface to enable communication coupling and may operate at millimeter wave or below 6GHz frequencies according to a cellular communication protocol such as the LTE protocol or the 5G NR protocol.

UE 702 may include a host platform 708 coupled with a modem platform 710. Host platform 708 may include application processing circuitry 712, which may be coupled with protocol processing circuitry 714 of modem platform 710. The application processing circuitry 712 may run various applications for the UE 702 that obtain/receive its application data. The application processing circuitry 712 may also implement one or more layers of 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.

Protocol processing circuitry 714 may implement one or more layer operations to facilitate the transmission or reception of data over connection 706. Layer operations implemented by the protocol processing circuit 714 may include, for example, Medium Access Control (MAC), Radio Link Control (RLC), Packet Data Convergence Protocol (PDCP), Radio Resource Control (RRC), and non-access stratum (NAS) operations.

Modem platform 710 may further include digital baseband circuitry 716, which digital baseband circuitry 716 may implement one or more layer operations "below" the layer operations performed by protocol processing circuitry 714 in the network protocol stack. These operations may include, for example, PHY operations including one or more of HARQ-ACK functions, scrambling/descrambling, encoding/decoding, layer mapping/demapping, modulation symbol mapping, received symbol/bit metric determination, multi-antenna port precoding/decoding, wherein these functions may include one or more of space-time, space-frequency, or spatial coding, reference signal generation/detection, preamble sequence generation and/or decoding, synchronization sequence generation/detection, control channel signal blind decoding, and other related functions.

Modem platform 710 may further include transmit circuitry 718, receive 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. Briefly, the transmit circuit 718 may include a digital-to-analog converter, a mixer, an Intermediate Frequency (IF) component, and the like; the receiving circuit 720 may include analog-to-digital converters, mixers, IF components, etc.; RF circuit 722 may include low noise amplifiers, power tracking components, and the like; RFFE circuitry 724 may include filters (e.g., surface/bulk acoustic wave filters), switches, antenna tuners, beam forming components (e.g., phased array antenna components), and so on. The selection and arrangement of components of transmit circuitry 718, receive circuitry 720, RF circuitry 722, RFFE circuitry 724, and antenna panel 726 (collectively, "transmit/receive components") may be specific to details of the particular implementation, e.g., whether the communication is Time Division Multiplexed (TDM) or Frequency Division Multiplexed (FDM), at mmWave or below 6GHz frequencies, etc. In some embodiments, the transmit/receive components may be arranged in a plurality of parallel transmit/receive chains, and may be arranged in the same or different chips/modules, etc.

In some embodiments, the protocol processing circuit 714 may include one or more instances of control circuitry (not shown) to provide control functionality for the transmit/receive components.

UE reception may be established by and via antenna panel 726, RFFE circuitry 724, RF circuitry 722, receive circuitry 720, digital baseband circuitry 716, and protocol processing circuitry 714. In some embodiments, antenna panels 726 may receive transmissions from AN 704 by receiving beamformed signals received by multiple antennas/antenna elements of one or more antenna panels 726.

UE transmissions may be established via and through protocol processing circuitry 714, digital baseband circuitry 716, transmit circuitry 718, RF circuitry 722, RFFE circuitry 724, and antenna panel 726. In some embodiments, a transmit component of UE 702 may apply spatial filtering to data to be transmitted to form a transmit beam transmitted by an antenna element of antenna panel 726.

Similar to UE 702, AN 704 may include a host platform 728 coupled with a modem platform 730. The host platform 728 may include an application processing circuit 732 coupled with a protocol processing circuit 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. The components of the AN 704 may be similar to, and substantially interchangeable with, the synonymous components of the UE 702. In addition to performing data transmission/reception as described above, the 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 data packet scheduling.

Fig. 8 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 methodologies discussed herein, according to some example embodiments. In particular, fig. 8 shows a schematic diagram of hardware resources 800, hardware resources 800 including one or more processors (or processor cores) 810, one or more memory/storage devices 820, and one or more communication resources 830, where each of these processors, memory/storage devices, and communication resources may be communicatively coupled via a bus 840 or other interface circuitry. For embodiments utilizing node virtualization (e.g., Network Function Virtualization (NFV)), hypervisor 802 may be executed to provide an execution environment for one or more network slices/subslices to utilize hardware resources 800.

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.

Memory/storage 820 may include a main memory, a disk storage device, or any suitable combination thereof. The memory/storage 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, or the like.

The communication resources 830 may include interconnection or network interface controllers, components, or other suitable devices to communicate with one or more peripherals 804 or one or more numbers via the network 808A database 806, or other network element. For example, communication resources 830 may include wired communication components (e.g., for coupling via USB, ethernet, etc.), cellular communication components, Near Field Communication (NFC) components, a network interface component, and/or a network interface component,

(or

Low energy) assembly,

Components, and other communication components.

The instructions 850 may include software, a program, an application, an applet, an app, 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. The instructions 850 may reside, completely or partially, within at least one of the processor 810 (e.g., in a cache of the processor), the memory/storage 820, or any suitable combination thereof. Further, any portion of instructions 850 may be communicated to hardware resource 800 from any combination of peripherals 804 or database 806. Thus, the memory of processor 810, memory/storage 820, peripherals 804, and database 806 are examples of computer-readable and machine-readable media.

The following paragraphs describe examples of various embodiments.

Example 1 includes AN apparatus for use in AN Access Node (AN) that functions as a primary 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): 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; and for each of the plurality of data forwarding address indication messages, receiving an extremely early state transition message or a failure report message sent by the SN in response to the data forwarding address indication message.

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

Example 3 includes the apparatus of example 1, wherein the very early state transition message contains 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 a candidate target AN.

Example 4 includes the apparatus of 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 some SN terminated bearers.

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

Example 6 includes the apparatus of example 1, wherein the plurality of DATA FORWARDING ADDRESS INDICATION messages are implemented as DATA forward ADDRESS INDICATION messages in the LTE-DC scenario or MR-DC scenario with an Evolved Packet Core (EPC).

Example 7 includes the apparatus of example 2 or 3, wherein, in the MR-DC scenario with the 5G core (5GC), the source identifier is a source NG-RAN node UE XnAP Identity (ID) and the target identifier is a target NG-RAN node UE XnAP ID.

Example 8 includes the apparatus of examples 2 or 3, wherein, in the LTE-DC scenario or MR-DC scenario with an Evolved Packet Core (EPC), the source identifier includes at least one of a source eNB UE X2AP Identification (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.

Example 9 includes AN apparatus for use in AN Access Node (AN) that functions as a Secondary Node (SN) connected to a primary node (MN) 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): receiving a plurality of data forwarding address indication messages from the MN, wherein each of the plurality of data forwarding address indication messages contains a data forwarding address corresponding to a candidate target AN; for each of the plurality of data forwarding address indication messages, sending an extremely early state transition message to the MN when performing early data forwarding for SN terminated bearers towards a data forwarding address contained in the data forwarding address indication message.

Example 10 includes the apparatus of example 9, wherein the processor circuit is further configured to cause the AN to: sending a failure report message to the MN when early data forwarding for the SN-terminated bearer is not performed towards the data forwarding address contained in the data forwarding address indication message.

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

Example 12 includes the apparatus of example 9, wherein the very early state transition message includes 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 a candidate target AN.

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 the SN terminated bearer.

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

Example 15 includes the apparatus of example 9, wherein the plurality of DATA FORWARDING ADDRESS INDICATION messages are implemented as DATA forward ADDRESS INDICATION messages in the LTE-DC or MR-DC scenarios with Evolved Packet Core (EPC).

Example 16 includes the apparatus of example 11 or 12, wherein, in the MR-DC scenario with the 5G core (5GC), the source identifier is a source NG-RAN node UE XnAP Identity (ID) and the target identifier is a target NG-RAN node UE XnAP ID.

Example 17 includes the apparatus of examples 11 or 12, wherein, in the LTE-DC scenario or MR-DC scenario with Evolved Packet Core (EPC), the source identifier includes at least one of a source eNB UE X2AP Identification (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.

Example 18 includes the apparatus of example 13, wherein the processor circuit is further configured to cause the AN to: stopping the early data forwarding already initiated for a part of the SN terminated bearers when the early data forwarding stop indication indicates to stop the early data forwarding already initiated for the part of the SN terminated bearers.

Example 19 includes a method for use in AN Access Node (AN) that operates as a primary 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, comprising: providing a plurality of data forwarding address indication messages to a wireless 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 extremely early state transition message or a failure report message sent by the SN in response to the data forwarding address indication message.

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

Example 21 includes the method of example 19, wherein the very early state transition message includes a source identifier that uniquely identifies AN association between the UE and the MN and a target identifier that uniquely identifies AN association between the UE and a candidate target AN.

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 already initiated for some SN terminated bearers.

Example 23 includes the method of 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.

Example 24 includes the method of example 19, wherein the plurality of DATA FORWARDING ADDRESS INDICATION messages are implemented as DATA forward ADDRESS INDICATION messages in the LTE-DC scenario or MR-DC scenario with Evolved Packet Core (EPC).

Example 25 includes the method of example 20 or 21, wherein, in the MR-DC scenario with the 5G core (5GC), the source identifier is a source NG-RAN node UE XnAP Identity (ID) and the target identifier is a target NG-RAN node UE XnAP ID.

Example 26 includes the method of example 20 or 21, wherein, in the LTE-DC scenario or MR-DC scenario with Evolved Packet Core (EPC), the source identifier includes at least one of a source eNB UE X2AP Identification (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.

Example 27 includes a method for use in AN Access Node (AN) that functions as a Secondary Node (SN) connected to a primary node (MN) 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): receiving a plurality of data forwarding address indication messages from the MN, 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; for each of the plurality of data forwarding address indication messages, providing an extremely early state transfer message to a radio interface for sending to the MN when performing early data forwarding for SN terminated bearers towards a data forwarding address contained in the data forwarding address indication message.

Example 28 includes the method of example 27, further comprising: sending a failure report message to the MN when early data forwarding for the SN-terminated bearer is not performed towards the data forwarding address contained in the data forwarding address indication message.

Example 29 includes the method of example 27, wherein each of the plurality of data forwarding address indication messages further includes a source identifier that uniquely identifies AN association between the UE and the MN and a target identifier that uniquely identifies AN association between the UE and a candidate target AN.

Example 30 includes the method of example 27, wherein the very early state transition message includes a source identifier that uniquely identifies AN association between the UE and the MN and a target identifier that uniquely identifies AN association between the UE and a candidate target AN.

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 the SN terminated bearer.

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

Example 33 includes the method of example 27, wherein the plurality of DATA FORWARDING ADDRESS INDICATION messages are implemented as DATA forward ADDRESS INDICATION messages in the LTE-DC or MR-DC scenarios with Evolved Packet Core (EPC).

Example 34 includes the method of example 29 or 30, wherein, in the MR-DC scenario with the 5G core (5GC), the source identifier is a source NG-RAN node UE XnAP Identity (ID) and the target identifier is a target NG-RAN node UE XnAP ID.

Example 35 includes the method of example 29 or 30, wherein, in the LTE-DC scenario or MR-DC scenario with Evolved Packet Core (EPC), the source identifier includes at least one of a source eNB UE X2AP Identification (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.

Example 36 includes the method of example 31, further comprising: stopping the early data forwarding already initiated for a part of the SN terminated bearers when the early data forwarding stop indication indicates to stop the early data forwarding already initiated for the part of the SN terminated bearers.

Example 37 includes AN Access Node (AN), comprising: apparatus for performing the method of any one of examples 19 to 36.

Example 38 includes AN Access Node (AN), comprising: a memory having instructions stored thereon; and a processor circuit coupled to the memory, wherein the instructions, when executed by the processor circuit, cause the processor circuit to perform the method of any of examples 18-36.

Although certain embodiments have been illustrated and described herein for purposes of description, a wide variety of alternate and/or equivalent embodiments or implementations calculated to achieve the same purposes may be substituted for the embodiments shown and described without departing from the scope of the present invention. This application is intended to cover any adaptations or variations of the embodiments discussed herein. Therefore, it is manifestly intended that the embodiments described herein be limited only by the claims and the equivalents thereof.

Claims

1. AN apparatus for use in AN Access Node (AN) that functions as a primary node (MN) connected with 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 to, during a Conditional Handover (CHO) procedure of a User Equipment (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; and

for each of the plurality of data forwarding address indication messages, receiving an extremely early state transfer message or a failure 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 comprises a source identifier that uniquely identifies AN association between the UE and the MN and a target identifier that uniquely identifies AN association between the UE and a candidate target AN.

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

4. The apparatus of claim 1, wherein each of the plurality of data forwarding address indication messages further comprises 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.

5. The apparatus of claim 1, wherein the plurality of data forwarding ADDRESS INDICATION messages are implemented as XN-U ADDRESS INDICATION messages in a MR-DC scenario with a 5G core (5 GC).

6. The apparatus of claim 1, wherein the plurality of DATA FORWARDING ADDRESS INDICATION messages are implemented as DATA forward ADDRESS INDICATION messages in the LTE-DC scenario or MR-DC scenario with Evolved Packet Core (EPC).

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

8. The apparatus of claim 2 or 3, wherein, in the LTE-DC scenario or MR-DC scenario with Evolved Packet Core (EPC), the source identifier includes at least one of a source eNB UE X2AP Identification (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.

9. AN apparatus for use in AN Access Node (AN) that functions as a Secondary Node (SN) connected with a primary node (MN) 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 to, during a Conditional Handover (CHO) procedure of a User Equipment (UE):

receiving a plurality of data forwarding address indication messages from the MN, wherein each of the plurality of data forwarding address indication messages contains a data forwarding address corresponding to a candidate target AN;

for each of the plurality of data forwarding address indication messages, sending an extremely early state transition message to the MN when performing early data forwarding for SN terminated bearers towards a data forwarding address contained in the data forwarding address indication message.

10. The apparatus of claim 9, wherein the processor circuit is further configured to cause the AN to:

sending a failure report message to the MN when early data forwarding for the SN-terminated bearer is not performed towards the data forwarding address contained in the data forwarding address indication message.

11. The apparatus of claim 9, wherein each of the plurality of data forwarding address indication messages further comprises a source identifier that uniquely identifies AN association between the UE and the MN and a target identifier that uniquely identifies AN association between the UE and a candidate target AN.

12. The apparatus of claim 9, wherein the very early state transition message comprises a source identifier that uniquely identifies AN association between the UE and the MN and a target identifier that uniquely identifies AN association between the UE and a candidate target AN.

13. The apparatus of claim 9, wherein each of the plurality of data forwarding address indication messages further comprises 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 the SN terminated bearer.

14. The apparatus of claim 9, wherein the plurality of data forwarding ADDRESS INDICATION messages are implemented as XN-U ADDRESS INDICATION messages in a MR-DC scenario with a 5G core (5 GC).

15. The apparatus of claim 9, wherein the plurality of DATA FORWARDING ADDRESS INDICATION messages are implemented as DATA forward ADDRESS INDICATION messages in the LTE-DC or MR-DC scenarios with Evolved Packet Core (EPC).

16. The apparatus according to claim 11 or 12, wherein, in a MR-DC scenario with a 5G core (5GC), the source identifier is a source NG-RAN node UE XnAP Identity (ID) and the target identifier is a target NG-RAN node UE XnAP ID.

17. The apparatus of claim 11 or 12, wherein, in the LTE-DC scenario or MR-DC scenario with Evolved Packet Core (EPC), the source identifier includes at least one of a source eNB UE X2AP Identification (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.

18. The apparatus of claim 13, wherein the processor circuit is further configured to cause the AN to:

stopping the early data forwarding already initiated for a part of the SN terminated bearers when the early data forwarding stop indication indicates to stop the early data forwarding already initiated for the part of the SN terminated bearers.

19. A method in AN Access Node (AN), wherein the AN functions as a primary node (MN) connected with 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 method comprising:

providing a plurality of data forwarding address indication messages to a wireless 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 extremely early state transition message or a failure report message sent by the SN in response to the data forwarding address indication message.

20. The method of claim 19, wherein each of the plurality of data forwarding address indication messages further comprises a source identifier that uniquely identifies AN association between the UE and the MN and a target identifier that uniquely identifies AN association between the UE and a candidate target AN.

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

22. The method of claim 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.

23. The method of claim 19, wherein the plurality of data forwarding address INDICATION messages are implemented as XN-UADDRESS INDICATION messages in an MR-DC scenario with a 5G core (5 GC).

24. The method of claim 19, wherein the plurality of DATA FORWARDING ADDRESS INDICATION messages are implemented as DATA forward ADDRESS INDICATION messages in the LTE-DC scenario or MR-DC scenario with Evolved Packet Core (EPC).

25. The method according to claim 20 or 21, wherein in a MR-DC scenario with a 5G core (5GC), the source identifier is a source NG-RAN node UE XnAP Identity (ID) and the target identifier is a target NG-RAN node UE XnAP ID.