Mobility for wireless access and backhaul

Abstract

Systems and methods are disclosed herein that relate to mobility for wireless access and backhaul. In one embodiment, a method performed by a first base station part of a Wireless Access and Backhaul (WAB) node comprises determining that a connection change of the first base station part of the WAB node from a first Access and Mobility Management Function (AMF) to a second AMF in a same or different Public Land Mobile Network (PLMN) is needed and performing actions that cause a connection change from the first AMF to the second AMF and handle User Equipment (UE) mobility in association with the connection change from the first AMF to the second AMF. In this manner, UE connectivity is ensured as the first base station part of the WAB node moves.

Description

MOBILITY FOR WIRELESS ACCESS AND BACKHAULRELATED APPLICATIONS

[0001] This application claims the benefit of provisional patent application serial number 63 / 552,963, filed February 13, 2024, the disclosure of which is hereby incorporated herein by reference in its entirety.TECHNICAL FIELD

[0002] The present disclosure relates to Wireless Access and Backhaul (WAB) in a cellular communications system.BACKGROUND

[0003] Third Generation Partnership Project (3 GPP) includes work related to wireless access and backhaul (WAB), such as Rel-19 study item description (SID) for the study on additional topological enhancements for New Radio (NR) in RP -234041. The study consists of two parts: (a) WAB, which refers to a mobile gNodeB (gNB) and (b) fifth generation (5G) femto.

[0004] A justification of the WAB part of the study item (SI) is that the legacy building blocks for 5G radio access network (RAN) topologies should be enhanced to provide a broader range of use cases, such as: (a) 5G access for user equipments (UEs) onboard aircrafts, cruise ships, helicopters, and vehicles in remote areas with limited sky visibility via an onboard gNB; (b) backhauling of next generation (NG) and Xn via terrestrial network (TN) and non-terrestrial network (NTN), including support of NTN <- TN handover for backhaul; (c) support for onboard / on-site mobile edge computing (MEC) and local services; (d) support for backhauling without RAN-sharing or roaming agreements between access public land mobile networks (PLMNs) and backhaul PLMN(s); and (e) backhauling for local gNB deployed in public safety or disaster recovery scenarios.

[0005] WAB may be aligned with vehicle mounted relay (VMR) use cases. It is expected that single-hop backhauling is sufficient for WAB and that there is no impact to UEs at this late stage of 5G deployment.

[0006] The objectives from the SID related to the WAB study are as follows: (a) study the architecture and protocol stack of supporting a gNB with mobile termination (MT) function providing protocol data unit (PDU) session backhaul; (b) study impact of WAB mobility within an existing radio access network (RAN) (e.g., inter-gNB neighbor relations); (c) identify necessary inter-gNB- and gNB-to-core network (CN) signalling to address the support of WAB; and (d) study signalling enhancements on resource multiplexing for WAB.

[0007] The WAB study does not preclude any backhaul scenario (e.g., NTN or TN).

[0008] A potential WAB architecture is illustrated in Figure 1. A key feature of the WAB architecture is that a WAB node consists of a WAB-gNB and a WAB-MT. The WAB-gNB part of an WAB node serves UEs, while the WAB node uses its WAB-MT part to connect with the rest of the mobile network, i.e., to connect to its serving gNB (the backhaul gNB (BH-gNB) in Figure 1). In this architecture, the PDU sessions established between the WAB-MT and the backhaul (BH) user plane function (UPF) are used to carry the NGAP and XnAP connections of the WAB- gNB.

[0009] The 5G core network (5GC) serving the WAB-gNB with its connected UEs (i.e., the UE-5GC, in Figure 1) may be the same as or different from the 5GC serving the WAB-MT (i.e., the BH 5GC in Figure 1).

[0010] Below is an excerpt from 3GPP Technical Specification (TS) 38.413 V18.0.0, which describes the NGAP (i.e., NG-C) interface.»»»»»»>Start of excerpt from TS 38.413 «««««««4.3.1.2 NG Control PlaneThe NG control plane interface (NG-C) is defined between the NG-RAN node and the AMF. The control plane protocol stack of the NG interface is shown on Figure 4.3.1.2-1. The transport network layer is built on IP transport. For the reliable transport of signalling messages, SCTP is added on top of IP. The application layer signalling protocol is referred to as NGAP (NG Application Protocol). The SCTP layer provides guaranteed delivery of application layer messages. In the transport, IP layer point-to-point transmission is used to deliver the signalling PDUs.[REPRODUCED HEREIN AS FIGURE 2]Figure 4.3.1.2-1 : NG-C Protocol StackNG-C provides the following functions:- NG interface management;- UE context management;- UE mobility management;- Transport of NAS messages;- Paging;- PDU Session Management;- Configuration Transfer;- Warning Message Transmission.Further details of NG-C can be found in TS 38.410

[0016] ,»»»»»»>End of excerpt from TS 38.413 «««««««

[0011] Below is an excerpt from 3GPP TS 38.410 vl 8.0.0, which describes the NG user plane(NG-U) interface.»»»»»»>Start of excerpt from TS 38.410 «««««««7.2 NG User PlaneThe NG user plane (NG-U) interface is defined between a NG-RAN node and a UPF. The NG-U interface provides non guaranteed delivery of PDU Session / MBS session user plane PDUs between the NG-RAN node and the UPF.The protocol stack for NG-U is shown in Figure 7.2-1.[REPRODUCED HEREIN AS FIGURE 3]Figure 7.2-1 : NG-U protocol structure for PDU / MBS Session»»»»»»>End of excerpt from TS 38.410 «««««<

[0012] PDU sessions are established in 5G between a UE and a data network to provide connectivity once the UE has been authenticated and established in a network. Further details can be found in the following excerpt from 3GPP TS 23.501.»»»»»»>Start of excerpt from TS 23.501 Section 5.6 «««««<The 5GC supports a PDU Connectivity Service i.e. a service that provides exchange of PDUs between a UE and a data network identified by a DNN. The PDU Connectivity Service is supported via PDU Sessions that are established upon request from the UE.Each PDU Session supports a single PDU Session type i.e. supports the exchange of a single type of PDU requested by the UE at the establishment of the PDU Session. The following PDU Session types are defined: IPv4, IPv6, IPv4v6, Ethernet, Unstructured.PDU Sessions are established (upon UE request), modified (upon UE and 5GC request) and released (upon UE and 5GC request) using NAS SM signalling exchanged over N1 between the UE and the SMF. Upon request from an Application Server, the 5GC is able to trigger a specific application in the UE. When receiving that trigger message, the UE shall pass it to the identified application in the UE. The identified application in the UE may establish a PDU Session to a specific DNN, see clause 4.4.5.In a PDU Session Establishment Request message sent to the network, the UE shall provide a PDU Session ID. The PDU Session ID is unique per UE and is the identifier used to uniquely identify one of a UE's PDU Sessions. The PDU Session ID shall be stored in the UDM to support handover between 3GPP and non-3GPP access when different PLMNs are used for the two accesses. The UE also provides as described in TS 24.501

[0047] :(a) PDU Session Type.(b) S-NSSAI of the HPLMN that matches the application (that is triggering the PDU Session Request) within the NSSP in the URSP rules or within the UE Local Configuration as defined in clause 6.1.2.2.1 ofTS 23.503

[0045] ,NOTE 4: If the UE cannot determine any S-NSSAI after performing the association of the application to a PDU Session, then it does not indicate any S-NSSAI in the PDU Session Establishment procedure as defined in clause 5.15.5.3.(c) S-NSSAI of the Serving PLMN from the Allowed NSSAI, corresponding to the S-NSSAI of the HPLMN (b).NOTE 5: In non-roaming scenario the mapping of the Allowed NSSAI to HPLMN S-NSSAIs is not provided to the UE (because the S-NSSAI of the Serving PLMN (c) has the same value of the S-NSSAI of the HPLMN (b)), therefore the UE provides in the PDU Session Request only the S-NSSAI of the Serving PLMN (c).NOTE 6: In roaming scenarios the UE provides in the PDU Session Request both the S-NSSAI of the HPLMN (b) and the S-NSSAI of the VPLMN from the Allowed NSSAI (c) that maps to the S-NSSAI of the HPLMN.(d) DNN (Data Network Name).(e) SSC mode (Service and Session Continuity mode defined in clause 5.6.9.2).A UE may establish multiple PDU Sessions, to the same data network or to different data networks, via 3 GPP and via and Non-3GPP access networks at the same time.A UE may establish multiple PDU Sessions to the same Data Network and served by different UPF terminating N6.A UE with multiple established PDU Sessions may be served by different SMF.»»»»»»>End of excerpt from TS 23.501 Section 5.6 «««««<

[0013] In 3GPP Technical Report (TR) 23.700-06 V0.1.0 produced by the SA2 3GPP Working Group (WG), a key issue on mobility of WAB nodes (therein referred to as the “MWAB nodes”) was captured. Further details regarding Key Issue #4 identified in 3GPP TR 23.700-06 are provided in the following excerpt.»»»»»»>Start of excerpt from TR 23.700-06 VO.1.0<<<<<<<<<<<5.4 Key Issue #4: Efficient mobility and service continuity when served by MWAB5.4.1 General descriptionWhen the moving vehicles are equipped with MWAB, the MWAB-gNB can provide 5G coverage and communication to UEs (inside the vehicle and / or in its vicinity), and connected wirelessly to the 5G network via a macro NG-RAN node. When one or a group of UEs are already served by the MWAB, there are two mobility scenarios to be studied as the following:- Scenario A (mobility within the same 5GC node): When the UEs are continuously served by a MWAB (e.g. inside the vehicle and / or in its vicinity), and this MWAB-gNB is moving around within a limited geographical area while keeping connecting with the same 5GC nodes (e.g. AMF and UPF). In this case, the UE keeps the connection with the MWAB, and there is no change of the connections as in figure 5.4.1-1. However, the change of the NG-RAN nodes serving the MWAB-UE and the MWAB location may have impact on the mobility or service restrictions to the UE served by the MWAB.- Scenario B (mobility between different 5GC nodes): When the UEs are continuously served by a MWAB (e.g. inside the vehicle and / or in its vicinity), and this MWAB is moving around over a long distance. To continue to provide services to the UEs, the MWAB needs to change the 5GC nodes it connects to. In this case, the UE keeps the connection with the MWAB-gNB, but there is a possible change of the AMF and UPF.NOTE 1 : For the above scenarios, whether the cell information in the System Information Broadcast (e.g. Cell ID, TAC) changes has RAN dependency.[REPRODUCED HEREIN AS FIGURE 4]Figure 5.4.1-1 : Scenarios for efficient mobility and service continuityThe following aspects need to be studied for UEs served by the MW AB in the case of mobility in the scenarios A and B:- Whether and how to enhance current procedures of mobility and service continuity for a UE. The following aspects need to be considered in potential solutions:- how to reflect the change of MW AB serving cell or location in the mobility management of the UEs served by the MW AB.- how to efficiently manage the mobility of the UEs served by the MW AB, when 5GC node change is necessary.NOTE 2: Mechanisms related to mobility management and service continuity have RAN dependency and should align with the progress of RAN WGs.»»»»»»>End of excerpt from TR 23.700-06 VO.1.0<<<<<<<<<<<SUMMARY

[0014] Systems and methods are disclosed herein that relate to mobility for wireless access and backhaul. In one embodiment, a method performed by a first base station part of a Wireless Access and Backhaul (WAB) node comprises determining that a connection change of the first base station part of the WAB node from a first Access and Mobility Management Function (AMF) to a second AMF in a same or different Public Land Mobile Network (PLMN) is needed and performing actions that cause a connection change from the first AMF to the second AMF and handle User Equipment (UE) mobility in association with the connection change from the first AMF to the second AMF. In this manner, UE connectivity is ensured as the first base station part of the WAB node moves.

[0015] In one embodiment, performing actions that cause the connection change from the first AMF to the second AMF and handle UE mobility in association with the connection change from the first AMF to the second AMF comprises instantiating a second logical base station part of a WAB node that connects to the second AMF and operates a target cell for handover of UEs served by a source cell operated by the first base station part of a WAB node and performing one or more actions related to handling of connectivity of one or more UEs in relation to the instantiation of the second base station part of a WAB node connected to the second AMF. In one embodiment, the second logical base station part of a WAB is configured with new configuration parameters used to establish a connection to the second AMF and to operate the target cell. In another embodiment, the first AMF and the second AMF are different AMFs, in a same PLMN. In one embodiment, one or more parameters for operation of the second base station part of a WAB nodeconnected to the second AMF are changed, relative to corresponding one or more parameters for operation of the first base station part of a WAB connected to the first AMF, in such a way that one or more UEs served by the first base station part of a WAB node are impacted. In one embodiment, the one or more UEs comprise one or more UEs in a connected state, and performing the one or more actions related to handling of connectivity of the one or more UEs comprises triggering a handover of the one or more UEs in the connected state from a first cell operated by the first base station part of a WAB node to a second cell operated by the second base station part of a WAB node. In one embodiment, the handover of the one or more UEs in the connected state is either NG-based or Xn-based. In one embodiment, the one or more UEs comprise one or more UEs in an idle state, and a Tracking Area Code (TAC) broadcasted on the second cell operated by the second base station part of a WAB node is different than a TAC broadcasted on the first cell operated by the first base station part of a WAB node. In one embodiment, the one or more UEs comprise one or more UEs in an inactive state, and a TAC and / or Radio Access Network (RAN) Notification Area Code (RANAC) broadcasted on the second cell operated by the second base station part of a WAB node is different than a TAC and / or RANAC broadcasted on the first cell operated by the first base station part of a WAB node. In one embodiment, the first base station part removes its connection with the first AMF. In one embodiment, after removing its connection with the first AMF and handover of the UEs in the connected state, the first base station part shuts down.

[0016] In one embodiment, performing actions that cause the connection change from the first AMF to the second AMF and handle UE mobility in association with the connection change from the first AMF to the second AMF comprises obtaining one or more configuration parameters needed to establish a connection to the second AMF, establishing a connection to the second AMF, based on the one or more configuration parameters, and performing one or more actions related to handling of connectivity of one or more UEs served by the first base station part of the WAB node in relation to movement of the first base station part of the WAB node from the first AMF to the second AMF.

[0017] In one embodiment, the first AMF and the second AMF are different AMFs, in a same PLMN. In one embodiment, upon movement of the first base station part of the WAB node from the first AMF to the second AMF, one or more parameters for operation of the first base station part of the WAB node are changed in such a way that the one or more UEs served by the first base station part of the WAB node are impacted. In one embodiment, the one or more UEs comprise one or more UEs in a connected state, and performing the one or more actions comprises triggering a handover of the one or more UEs in the connected state within the first base station part of theWAB node. In one embodiment, the one or more UEs comprise one or more UEs in an idle state, and performing the one or more actions comprises broadcasting a TAC associated to the second AMF. In another embodiment, the one or more UEs comprise one or more UEs in an inactive state, and performing the one or more actions comprises broadcasting a TAC and / or RANAC associated to the second AMF. In another embodiment, upon movement of the first base station part of the WAB node from the first AMF to the second AMF, at least some parameters for operation of the first base station part of the WAB node remain the same after the connection change in such a way that the one or more UEs served by the first base station part of the WAB are not affected by the connection change. In one embodiment, performing the one or more actions comprises triggering transfer of UE contexts of the one or more UEs from the first AMF to the second AMF. In another embodiment, performing the one or more actions comprises sending, to the first AMF, one or more indications to transfer UE contexts of the one or more UEs to the second AMF. In another embodiment, performing the one or more actions comprises sending, to the second AMF, one or more indications to fetch UE contexts of the one or more UEs from the first AMF. In another embodiment, performing the one or more actions comprises triggering release of all connected UEs such transition of the connected UEs to an idle mode.

[0018] In another embodiment, the first AMF is in a first PLMN, and the second AMF is in a second PLMN that is different than the first PLMN. In one embodiment, performing the one or more actions comprises sending to the one or more UEs an indication for the one or more UEs to transition to an idle state.

[0019] In one embodiment, the first base station part removes its connection with the first AMF.

[0020] In one embodiment, determining that the connection change from the first AMF to the second AMF is needed comprises determining that the connection change from the first AMF to the second AMF is needed based on a current location of the first base station part of the WAB node.

[0021] In one embodiment, determining that the connection change from the first AMF to the second AMF is needed comprises determining that the connection change from the first AMF to the second AMF is needed based on a current location of the first base station part of the WAB node and / or one or more additional criteria.

[0022] Corresponding embodiments of a first base station part of a WAB node are also disclosed. In one embodiments, a first base station part of a WAB node is adapted to determine that a connection change of the first base station part from a first AMF to a second AMF in a same or different PLMN is needed and perform actions that cause a connection change from the firstAMF to the second AMF and handle User Equipment, UE, mobility in association with the connection change from the first AMF to the second AMF.BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawing figures incorporated in and forming a part of this specification illustrate several aspects of the disclosure, and together with the description serve to explain the principles of the disclosure.

[0024] Figure 1 illustrates a Wireless Access and Backhaul (WAB) architecture;

[0025] Figure 2 is a reproduction of Figure 4.3.1.2-1 of 3rdGeneration Partnership Project(3GPP) Technical Specification (TS) 38.413 V18.0.0;

[0026] Figure 3 is a reproduction of Figure 7.2-1 of 3GPP TS 38.410 V18.0.0;

[0027] Figure 4 is a reproduction of Figure 5.4.1-1 of 3GPP Technical Report (TR) 23.700-06 V0.1.0;

[0028] Figure 5 is a flow chart that illustrates a procedure performed by a base station part of a WAB node in accordance with an embodiment of the present disclosure;

[0029] Figure 6 is a flow chart that illustrates a procedure performed by a base station part of a WAB node in accordance with another embodiment of the present disclosure;

[0030] Figure 7 is a flow chart that illustrates a procedure performed by a base station part of a WAB node in accordance with another embodiment of the present disclosure;

[0031] Figure 8 shows an example of a communication system in accordance with some embodiments;

[0032] Figure 9 shows a User Equipment (UE) in accordance with some embodiments;

[0033] Figure 10 shows a network node in accordance with some embodiments;

[0034] Figure 11 is a block diagram of a host, which may be an embodiment of the host ofFigure 8, in accordance with various aspects described herein;

[0035] Figure 12 is a block diagram illustrating a virtualization environment in which functions implemented by some embodiments may be virtualized; and

[0036] Figure 13 shows a communication diagram of a host communicating via a network node with a UE over a partially wireless connection in accordance with some embodiments.DETAILED DESCRIPTION

[0037] Some of the embodiments contemplated herein will now be described more fully with reference to the accompanying drawings. Embodiments are provided by way of example to convey the scope of the subject matter to those skilled in the art.

[0038] There currently exist certain challenges. For example, a Wireless Access and Backhaul (WAB) node will likely consist of a WAB-gNodeB (gNB) and a WAB-Mobile Termination (MT) (i.e., WAB-User Equipment (UE)). The WAB-gNB part of a WAB node serves UEs, while the WAB node uses its WAB-MT part to connect with a mobile network (the backhaul (BH)-gNB in Figure 1). Protocol Data Unit (PDU) Session(s) of the WAB-MT provide Internet Protocol (IP) connectivity for the WAB-gNB. In this architecture, the PDU session(s) established between the WAB-MT and the BH-User Plane Function (UPF) (see Figure 1) are used to provide IP connectivity for Next Generation (NG) Application Protocol (NGAP) and Xn Application Protocol (XnAP) connections of the WAB-gNB, as well as to provide connectivity to the Operations and Management (0AM) system. The WAB-gNB may connect to the same Access and Mobility Management Function (AMF) and Core Network (CN) functions as the WAB-MT (and BH-gNB), or it may connect to different AMF(s) and CN functions.

[0039] According to the above, all traffic from the WAB-gNB (including at least the NG, and Xn communication for interface management and individual UE signaling and User Plane (UP) traffic, 0AM connection traffic) will be backhauled through PDU sessions that are established between the WAB-MT and BH-5111Generation Core (5GC).

[0040] Third Generation Partnership Project (3GPP) Technical Report (TR) 23.700-06 vO. l.O produced by the SA23GPP WG defines a key issue on mobility of WAB nodes, with two scenarios (i.e., Scenario A for mobility within the same 5GC node) and Scenario B for mobility between different 5GC nodes), as included in the excerpt from 3GPP TR 23.700-06 included in the Background section above. 3GPP TR 23.700-06 further calls for consideration of the following aspects pertinent to the mobility scenarios:• how to reflect the change of WAB (referred to as “MW AB”) serving cell or location in the mobility management of the UEs served by the MW AB; and• how to efficiently manage the mobility of the UEs served by the MW AB when 5GC node change is necessary.

[0041] Thus, a problem exists regarding how to support handling of UEs connected to the (M)WAB node when the (M)WAB node undergoes mobility between different 5GC nodes.

[0042] Certain aspects of the disclosure and their embodiments may provide solutions to these or other challenges. For example, particular embodiments handle UE connections during WAB node mobility, e.g., the mobility of the WAB-gNB part of the WAB node.

[0043] Certain embodiments may provide one or more of the following technical advantages. For example, particular embodiments ensure the continuity of UE connectivity as the WAB node moves.

[0044] Particular examples are presented on a non-limiting example of WAB nodes, but they apply to any kind of moving Radio Access Network (RAN) node or any RAN node that uses wireless backhaul.

[0045] Particular embodiments described herein apply to both Next Generation (NG) and Xn interface connections as well as for the connection between the WAB-gNB and the 0AM.

[0046] Herein, depending on the scenario, the term “link degradation” means that either the conditions on the link are getting worse (but the link can still be used for communication) or the link has completely failed.

[0047] The procedures used herein may be class- 1 or class-2 procedures. They may be new procedures or enhancements of existing procedures.

[0048] The expressions “X served by Y” or “X is connected to Y” mean that there is a logical interface connection between network nodes X and Y. When X is a UE, this means that node X and the RAN node serving the UE have a logical connection associated to this UE.

[0049] Unless stated otherwise, the WAB-MT and the WAB-gNB are co-located, i.e., they are a part of the same WAB node.

[0050] The WAB-gNB may connect to one or more CN instances (e.g., one or more AMFs). Among these instances, the CN nodes that serve a UE are referred to as, e.g., “UE’s AMF”, “UE’s UPF”, etc.

[0051] Unless stated otherwise, “traffic” refers to both user plane traffic and control plane signaling.

[0052] The terms “CN nodes”, “core network nodes”, and “CN functions” are used interchangeably without losing the meaning, and they may refer to one or more of the following: AMF, User Plane Function (UPF), Session Management Function (SMF), or any other 5GC node / function.

[0053] The term “core network node” or “BH-5GC node” or “UE-5GC node” may refer to the AMF, UPF, SMF or any other 5GC node serving RAN nodes and / or UEs.

[0054] The terms “NG connection”, “NGAP connection” and “NG-C interface instance” are used interchangeably.

[0055] The terms “new AMF” and “target AMF” are used interchangeably.

[0056] Particular embodiments may apply to both single- and dual-connected WAB nodes.

[0057] Particular embodiments apply to both the case when all UEs connected to the WAB- gNB are served by the same AMF, and the case where multiple AMFs serve these UEs. Particular embodiments also apply where the WAB-gNB has an NGAP connection with the AMF serving the WAB-MT, and when it does not.

[0058] The term “different core network” may refer to a core network of another Public Land Mobile Network (PLMN), or it may apply to different part of a core network of the same PLMN (e.g., a different AMF or set of AMFs).

[0059] Particular embodiments apply to New Radio (NR) as well as future Radio Access Technologies (RATs) such as beyond 3 GPP Rel-18.

[0060] The terms “0AM” and “0AM system” are used interchangeably.

[0061] The term “cell ID” may apply to NR Cell Global Identity (NCGI), NR Cell Identity(NCI), or celllD.

[0062] The terms “old AMF” and “new AMF” refer to the AMFs serving the UEs connected to the WAB-gNB before and after WAB-gNB connected to the new AMF, respectively.

[0063] The terms “RRC state” and “RRC mode” are used interchangeably.

[0064] All examples listed herein are non-limiting.

[0065] Different variants and embodiments below may be combined.

[0066] Particular embodiments include a set of methods for handling the connectivity of UEs served by a moving WAB-gNB. In those assumed scenarios in which the change of AMF serving the WAB-gNB is supported, the new AMF is in a different set than the old AMF. Depending on the scenario, the old and the new AMF / AMF set may be in the same or in different PLMNs.

[0067] Particular embodiments include the scenarios in which WAB-gNB moves in the same PLMN:• Scenario 1-1 : The WAB-gNB connects to the same or a new AMF in the same PLMN, and the parameters needed for WAB-gNB operation (e.g., cell ID(s), gNB ID, Physical Cell ID(s) (PCI(s)) and Tracking Area Code (TAC) served by the WAB-gNB) are changed.• Scenario 1-2: The WAB-gNB connects to the same or a new AMF in the same PLMN, and the parameters needed for WAB-gNB operation (e.g., cell ID(s), gNB ID, PCI(s) and TAC served by the WAB-gNB) remain the same.

[0068] Particular embodiments include the scenarios in which WAB-gNB roams to another PLMN:• Scenario 2: The WAB-gNB connects to a PLMN other than its home PLMN. The WAB- MT may be connected to the same or a different PLMN.

[0069] The embodiments described for one scenario may be used in other scenarios as well.

[0070] Upon WAB-gNB mobility, some, or all the following parameters of the WAB-gNB need to be updated, depending on the scenario (non-limiting examples):Cell ID(s). gNB ID.• Global gNB ID.• PCI(s).• PLMN ID.• TAC(s) and RAN-based Notification Area Code(s) (RANAC(s)).• Slice support list.• RAN node name.• Physical layer parameters, such as uplink (UL) / downlink (DL) Time Division Duplexing (TDD) patterns.

[0071] Particular embodiments are for use with Scenario 1-1. In these embodiments, the WAB-gNB connects to the same or a new AMF in the same PLMN, and the parameters needed for WAB-gNB operation are changed in such a way that served UEs are impacted. For example, if the cell ID(s), PCI(s), gNB ID and TAC served by the WAB-gNB are changed, the UEs are impacted, and special handling is needed.

[0072] The steps are illustrated in Figure 5 and described below. Some or all the steps may be optional and may be executed in an order different than presented.

[0073] STEPS 500 and 502: WAB-gNB decides if it needs to connect to a new AMF and provides / receives new configuration. In other words, the WAB-gNB determines whether a handover (also referred to herein as a “connection change” of the WAG-gNB to avoid any confusion with UE handover) from a current AMF to which the WAB-gNB is connected to a new AMF is needed.

[0074] Based on its current location and / or additional criteria, in STEP 500, the WAB-gNB determines if connection to a new AMF (or one or more AMFs) should be established.

[0075] In STEP 502, the WAB-gNB obtains the new configuration parameters needed to establish the connection to the new AMF and the parameters needed for it to operate and serve UEs in the new area (e.g., a new set of cell IDs, gNB ID, PCI(s), TAC and RANAC). The connections towards old AMF(s) may still be maintained, at least for some time, as long as it is required by the steps below. As would be understood by those of skill in the art the WAB-gNB may obtain these new configuration parameters from, e.g., 0AM, either prior to the connection change or some time before (e.g., the new configuration parameters are preconfigured).

[0076] The update of parameters may require powering up of new cells, to avoid loss of UE connectivity.

[0077] STEP 504: WAB-gNB connects to the new AMF(s) and powers up new cells.

[0078] Based on the new configuration, the WAB-gNB connects to one or more new AMFs and may power up (i.e., start serving) one or more new cells with new cell IDs. Besides the cell IDs, additional parameters may be updated.

[0079] When setting up the NG connection to a new AMF, the WAB-gNB indicates to the AMF, among other things, the list of supported TACs and other parameters. This indication can also be done by using other messages, e.g., the RAN CONFIGURATION UPDATE message (e.g., if the AMF is not changed or after the NG setup procedure to a new AMF has been completed).

[0080] Each served cell pertains to a TAC, and, during NG connection setup with a new AMF, the WAB-gNB indicates to the AMF the TAC(s) that the gNB supports.

[0081] STEP 506: Handling of UE connectivity.

[0082] The change of some of the parameters affects the UE connectivity and requires special handling. Depending on the RRC state of each UE, the served UEs are handled as follows.

[0083] For UEs in RRC CONNECTED state, the WAB-gNB triggers intra-WAB-gNB handover (HO) for its served UEs (STEP 506A). The HO may be executed between the old (source) and new (target) cell, both served by the WAB-gNB. This is different than legacy, where intra-gNB HO does not include a change of AMFs. In some embodiments, NG-based HO of UEs with or without AMF change is executed. In some embodiments, Xn-based UE HO may be executed, e.g., if the AMF is not changed.

[0084] If the new cell has a TAC different than the old cell, the UE will detect the new TAC and if the new TAC is outside the UE’ s registration area (RA), the UE will trigger the Non-Access Stratum (NAS) Mobility Registration Update procedure towards the core.

[0085] The NAS message can be carried inside the UL NAS TRANSPORT message or some other message. The UL NAS TRANSPORT message contains the RAN and AMF NGAP UE IDs pertaining to the association with the old AMF. In this case, the new AMF understands that the UE has been connected to another AMF.

[0086] If the UL NAS TRANSPORT message is used for this purpose, the WAB-gNB includes the new TAC in UE location information (ULI) of the UE. As mentioned above, each TAC is supported by an AMF, meaning that the NAS Mobility Registration message will reach the AMF pertaining to the new TAC. If this TAC is not a part of the current registration area (RA) of the UE, the AMF needs to update the UE via NAS with the new TAC.

[0087] The old AMF identifier (e.g., AMF Name, Globally Unique AMF Identity (GUAMI)) is included in the NGAP message, to the new AMF.

[0088] The WAB-gNB may explicitly indicate the need of UE context transfer (e.g., due to intra-WAB-gNB cell mobility but with AMF change).

[0089] Based on the received message and 5G Globally Unique Temporary Identity (5G- GUTI) included in the NAS Mobility Registration Request message, or the old AMF identifier received, the new AMF realizes that it does not have the UE context. Based on the 5G-GUTI in the message, the AMF determines which AMF currently has the UE context (e.g., one of the old AMFs that the WAB-gNB was or still is connected to). The new AMF fetches the UE context from the old AMF. This is different compared to legacy handling, where the UE context is fetched only for UEs that trigger the NAS Mobility Registration Request procedure in RRC IDLE.

[0090] As an additional embodiment, all or a part of UEs in RRC CONNECTED may be handed over from the old cell to the new cell at the same time, e.g., so called group handover. For the former, one group is defined, for the latter, multiple groups are formed wherein each group contains a number of UEs. UEs that are in the same group may belong to the same serving cell, the same TAC, and / or same or similar services (e.g., services associated with similar QoS requirements). With group handover, the required signaling messages between nodes may be minimized (therefore signaling overhead can be reduced). In this case, the same signaling message can contain all UE IDs in the same group, the same cell ID (if the UEs share the same cell ID), the same TAC (if the UEs share the same TAC).

[0091] In an example, handover signaling (e.g., handover command) may be sent to all UEs by the WAB-gNB in the same group using the same signaling.

[0092] In an example, a NGAP signaling message may be exchanged between the WAB-gNB and the AMF (old or new) for the group instead of a single UE (context).

[0093] For UEs in RRC IDLE state, when a UE served by the WAB-gNB detects a new TAC, it triggers the NAS Mobility Update procedure towards the core network, where the NAS message may be carried in, e.g., INITIAL UE MESSAGE or another message towards the same AMF or new AMF. The AMF handles the NAS procedure as normal and retrieves UE context from old AMF if there is AMF change. In other words, for UEs in RRC IDLE state, the WAB-gNB broadcast the TAC in system information (e.g., in the conventional manner) and, if the TAC is a new TAC (i.e., a new TAC broadcasted on the new cell that is different than the TAC previously broadcast on the old cell), this causes the UE to trigger the NAS Mobility Update procedure towards the core network as described above (STEP 506B).

[0094] For UEs in RRC INACTIVE state, when a UE served by the WAB-gNB detects a new TAC / RANAC, it triggers the Access Stratum (AS) RAN Notification Area (RNA) update procedure towards WAB-gNB and NAS Mobility Registration Request towards the core network. The AMF handles the NAS procedure as normal and retrieves UE context from the old AMF if there is AMF change. In other words, for UEs in RRC INACTIVE state, the WAB-gNB broadcastthe TAC / RANAC in system information (e.g., in the conventional manner) and, if the TAC / RANAC is a new TAC / RANAC (i.e., a new TAC / RANAC broadcasted on the new cell that is different than the TAC / RANAC previously broadcast on the old cell), this causes the UE to trigger the AS RNA update procedure towards the WAB-gNB and the NAS Mobility Registration Request towards the core network as described above (STEP 506C).

[0095] With respect to UE handover, several options may be used. In some embodiments, the WAB-gNB serves both the source and target cells for UE handover (see “Alternative 1” noted in Figure 5). In some embodiments, a new, second logical WAB-gNB is powered up (i.e., instantiated) (see “Alternative 2” noted in Figure 5). It connects to the new AMF and powers up the target cells for UE handover. The second logical WAB-gNB connects to the new AMF and powers up the target cells for UE handover using the new configuration parameters (see STEP 502). Then the UEs are handed over between the original WAB-gNB and the second logical WAB-gNB. In other words, as discussed above for UEs in the RRC CONNECTED state, a handover from the old AMF to the new AMF is triggered. However, in the case for the second logical WAB-gNB is used, the handover from the old AMF to the new AMF that is triggered is an inter-WAB-gNB handover rather than an intra-WAB-gNB handover (which was the case described above for the single WAB-gNB scenario). Similarly, as discussed above, for UEs in the RRC IDLE state, the TAC is broadcast by, in this case, the target cell(s) for the UE handover, which is operated by the new, second logical WAB-gNB. Likewise, for UEs in the RRC_INACTIVE state, the TAC / RANAC is broadcast by, in this case, the target cell(s) for the UE handover, which is operated by the new, second logical WAB-gNB. After all intended HOs have been completed, the first WAB-gNB may remove its NG interface connections and it may be shut down. From that point on, the second logical WAB-gNB assumes the role of the “original” WAB-gNB and continues to serve UEs. Thus, in other words, when a second logical WAB-gNB is used for the handover to the new AMF, STEPS 504 and 506 involve the second logical WAB- gNB (e.g., STEPS 506A, 506B, and 506C are performed by the second logical WAB-gNB.

[0096] STEP 508: NGAP removal towards old AMF(s).

[0097] Once all the UEs have been handed over to the new cell(s), the NGAP connections between the WAB-gNB and the AMFs may be removed.

[0098] STEP 508 Alternative: NGAP suspend and resume.

[0099] If WAB-gNB moves with patterns and connects / disconnects to the AMF, the NGAP connection may be suspended and resumed.

[0100] Particular embodiments apply for Scenario 1-2. These embodiments mainly target the case when the WAB-gNB needs to connect to a new AMF in the same PLMN, and at least someof the parameters needed for WAB-gNB operation (e.g., cell ID(s) and TAC served by the WAB- gNB) remain the same in such a way that the UEs are not affected. In other words, it is not necessary to execute intra-WAB-gNB HO to maintain UE connectivity.

[0101] The steps are illustrated in Figure 6 and described below. Some or all the steps may be optional and may be executed in an order different than presented.

[0102] STEPS 600 and 602: WAB-gNB decides to connect to new AMF(s).

[0103] Based on its current location and / or additional criteria, the WAB-gNB determines that connection to a new AMF (or one or more AMFs) should be established (STEP 600).

[0104] The WAB-gNB is provisioned with the configuration parameters to establish the connection to the new AMF (STEP 602). Meanwhile, the parameters needed for the WAB-gNB to operate and serve UEs in the new area remain the same, in such a way that the UE connectivity is not affected (i.e., as discussed above, it is not necessary to execute a handover to maintain UE connectivity). For example, the WAB-gNB is instructed / configured to retain cell IDs, gNB ID, TACs etc. that it previously / currently used.

[0105] STEP 604: WAB-gNB connects to new AMF.

[0106] The WAB-gNB sets up NG connection towards one or more new AMF(s).

[0107] When setting up the NG connection to a new AMF, the WAB-gNB indicates to theAMF the needed parameters, such as the supported PLMN ID(s), TACs and the supported slices.

[0108] Herein, it is assumed that the (cell-related) parameters that the UEs observe are identical to the cell-related parameters that were valid at the WAB-gNB prior to connecting to the new AMF(s). Consequently, because cell-related parameters remain the same, the UEs are not affected (i.e., as discussed above, it is not necessary to execute a handover to maintain UE connectivity) - the fact that the WAB-gNB is now connected to new AMF(s) is transparent to the UEs served by the WAB-gNB.

[0109] The connections towards old AMF(s) may still be maintained, at least for some time, as long as it is required by the steps below. However, the WAB-gNB needs to update the old AMF to remove certain information, e.g., supported PLMN IDs, TACs and supported slices by using RAN Configuration Update procedure.

[0110] STEP 606: Triggering of transfer of UE contexts between old and new AMFs.[OHl] After the WAB-gNB has successfully connected to a new AMF, the transfer of UE contexts from the old AMF(s) to new AMF(s) is triggered.

[0112] In one embodiment, the WAB-gNB triggers the UE context transfer from the old AMF to new AMF (STEP 606A). In one embodiment, the WAB-gNB sends an indication to the old AMF(s) that UE contexts should be moved (STEP 606A-1). As discussed below, the indicationmay be a per UE indication (i.e., separate indication for every UE) or a group indication for all UEs.

[0113] In some embodiments, a separate indication for every UE can be sent. In some embodiments, a group indication for all UEs is sent. The group indication may contain an indication “all UEs served by the WAB-gNB”, or a list of RAN and / or AMF NGAP UE IDs or another type of UE ID may be sent.

[0114] All or a part of UEs may be included in the same group. For the former, one group is defined. For the latter, multiple groups are formed wherein each group contains a number of UEs. UEs in the same group may belong to the same serving cell, the same TAC, and / or same or similar services (e.g., services associated with similar QoS requirements). All UEs in the same group may be associated with the same RAN state (e.g., RRC IDLE, RRC INACTIVE or RRC CONNECTED) or CN state (e.g, CM IDLE or CM CONNECTED).

[0115] The indication may be sent in different messages, some (non-limiting) examples:• RAN CONFIGURATION UPDATE• NG RESET• NGAP REMOVAL REQUEST, NGAP SUSPENSION REQUEST,

[0116] In some embodiments, a UE-associated message is used. In some embodiments, a non- UE-associated message is used.

[0117] In some embodiments, the WAB-also sends to the old AMF(s) the ID(s) of the new AMF(s), e g., the GUAMI (STEP 606A-2).

[0118] In some embodiments, the AMF may reject or fail to push / retrieve some of the UE contexts. In some cases, a corresponding message indicating a failure to push / retrieve contexts may be defined.

[0119] The old AMF then sends the UE contexts (either for each UE separately or for a group of UEs) to the new AMF via the Service Based Interface (SBI) based service operation (e.g., either use existing Namf Communication CreateUeContext with new parameter indicating that it is related to WAB-gNB move with AMF change, or by using a newly defined service operation). The old AMF may also include an indicator of the WAB-gNB.

[0120] After receiving the UE context from the old AMF, the new AMF triggers N2 connection rebinding with Stream Control Transmission Protocol (SCTP) association based on the received RAN NGAP ID for the UE provided by the WAB-gNB / Old AMF as part of the UE context.

[0121] In one embodiment, the WAB-gNB triggers the new AMF to fetch UE contexts from the old AMF (STEP 606B).

[0122] In one embodiment, when setting up NG connection to the new AMF, the WAB-gNB explicitly indicates to the new AMF that context fetch is needed.

[0123] In some embodiments, the WAB-gNB triggers NGAP message (e.g., UE context transfer request, or a newly defined or existing UE-associated or non-UE-associated message) towards new AMF for each UE or group of UEs to rebind the UE N2 connection to the new SCTP association and indicates the ID of the old AMF(s), e.g., the GUAMI of the old AMF, old AMF Name.

[0124] In some embodiments, the WAB-gNB may indicate the list of UE IDs whose contexts should be fetched, e.g., their RAN and / or AMF NGAP UE IDs or another type of UE ID. Alternatively, instead of explicitly indication UE IDs, the WAB-gNB may send a general indication “context fetch needed for all UEs served by WAB-gNB”.

[0125] Based on the old AMF info (e.g., GUAMI of the old AMF from WAB-gNB), the new AMF initiates the communication with the old AMF and retrieves the UE contexts (either for each UE separately or for a group of UE) from the old AMF via the SBI based service operation (e.g., either use existing Namf Communication UEContextTransfer with new parameter indicating that it is related to WAB-gNB move with AMF change, or by using a newly defined service operation).

[0126] In some embodiments, the new AMF may also include an indicator of the WAB-gNB.

[0127] The new AMF may respond to WAB-gNB to confirm the rebinding of UE N2 connection.

[0128] As described above, all or a part of UEs may be included in the same group. For the former, one group is defined, for the latter, multiple groups are formed wherein each group contains a number of UEs. UEs in the same group may belong to the same serving cell, the same TAC, and / or same or similar services (e.g., services associated with similar QoS requirements). All UEs in the same group may be associated with the same RAN state (e.g., RRC IDLE, RRC INACTIVE or RRC CONNECTED) or CN state (e g., CM IDLE or CM CONNECTED). In this case, for the UEs in the same group, their contexts can be fetched or moved at the same time.

[0129] These embodiments may also be applied for Scenario 1-1 (e.g., WAB-gNB can initiate the above steps towards the new AMF before the UE triggers the NAS Mobility registration procedure as described with respect to scenario 1-1)

[0130] As an alternative to STEP 606, the WAB-gNB may trigger the release of all connected UE and force the UEs to enter the RRC IDLE mode and trigger NAS Mobility Registration request to switch to the new AMF.

[0131] Particular embodiments apply for Scenario 2. In these embodiments, the WAB-gNB connects to a PLMN other than its home PLMN. The WAB-MT may be connected to the same or a different PLMN.

[0132] The steps are illustrated in Figure 7 and described below. Some or all the steps may be optional and may be executed in an order different than presented.

[0133] STEPS 700 and 702: WAB-gNB decides to connect to new AMF(s) and receives configuration parameters to establish a connection to the new PLMN as well as parameters needed for the WAB-gNB to operate and serve UEs in the new PLMN.

[0134] Based on its current location and / or additional criteria, the WAB-gNB determines that connection to a new PLMN should be established. This may include connecting to one or more new AMFs in the new PLMN (STEP 700).

[0135] The WAB-gNB is provisioned with the configuration parameters to establish the connection to the new PLMN (STEP 702). Meanwhile, the WAB-gNB is also provisioned with the parameters needed for the WAB-gNB to operate and serve UEs in the new PLMN.

[0136] STEP 704: Handling of UEs and connecting to new AMF(s) in the new PLMN.

[0137] In some embodiments, the WAB-gNB sends its served UEs to RRC IDLE state. Once the WAB connects to the new PLMN, the UEs will detect the new PLMN and Tracking Area (TA) and try to connect to the new PLMN. The strongest cell detected by the UEs will likely be one of the cells served by the WAB-gNB, meaning that the UEs will connect to a cell in the new PLMN served by the WAB-gNB.

[0138] For the WAB-gNB to be able to execute the above, the WAB-gNB needs to connect to one or more AMFs in the new PLMN.

[0139] In some variants, the WAB-gNB first sends the UEs to RRC IDLE mode, and then connects to the new PLMN and AMFs. In some variants, the WAB-gNB first connects to the new PLMN and then sends the UEs to RRC IDLE state.

[0140] This can be done, for example, if a new (i.e., second) logical WAB-gNB is powered up. Then the new logical WAB-gNB connects to the new AMF and powers up one or more cells pertaining to the new PLMN. After all intended HOs have connected to the new PLMN, the first WAB-gNB may remove its NG interface connections and it may be shut down. Then the UEs in RRC IDLE mode detect the new PLMN and TA and try to connect. From that point on, the new logical WAB-gNB assumes the role of the “original” WAB-gNB, which now operates in a new PLMN, and continues to serve UEs.

[0141] The embodiment for Scenario 1-1 may be applied to this scenario, e.g., whereas one of the WAB-gNB parameters that change is the PLMN ID of its served cells. Then, the UEs arehanded over from the cells pertaining to the old PLMN ID and old PLMN to the cells pertaining to the new PLMN ID and new PLMN.

[0142] Same as embodiments in other options, some UEs may be included in the same group. In such case, actions can be performed for the group instead of each UE individually. Signaling overhead can be reduced.

[0143] Some embodiments include data forwarding. In one embodiment, the data buffered at the source WAB-gNB is forwarded to the target WAB-gNB by implementation, because it is one physical NG-RAN node. The data buffered at source core network (CN) is forwarded to the target CN via indirect data forward. The data buffered at the BH is forwarded either via the CN nodes, or as in below.

[0144] In one embodiment, when BH has changed, the source BH creates the Xn data forwarding tunnel to the target BH. The source BH-gNB is made aware of the target BH-gNB by WAB-MT, alternatively by CN / OAM. In one embodiment, when BH is the same during mobility, it moves the connection from the source CN to target CN, the data buffered at BH is forwarded by gNB implementation.

[0145] In one embodiment, the source WAB-gNB proposes the data forwarding, (when confirmed), repack the buffered data (to be forwarded) with the target CN node IP address. The source WAB-gNB obtains such information via 0AM or NGAP procedure from the source CN.

[0146] In one embodiment, the source WAB-gNB proposes the data forwarding, (when confirmed) repack the buffered data (to be forwarded) with the target BH-gNB IP address and the target BH PDU session / target WAB-gNB identifier. The source WAB-gNB obtains such information via 0AM or NGAP procedure from the source CN.

[0147] In one embodiment, the uplink data forwarding is sent between the source WAB-gNB and the target CN. The downlink data forwarding is sent between the source WAB-gNB to the target WAB-gNB via the target BH-gNB.

[0148] In one embodiment, a “data forwarding” BH session is setup by the source WAN- gNB, when the data forward proposal is accepted by the target. It is specified that the new destination IP address is indicated for the data forwarding tunnel and the data buffered at the BH could be sent within the data forwarding tunnel.

[0149] Non-limiting implementation examples in TS 38.413 vl8.0.0 are shown below. New part are shown via underlined text.»»»»»»»»»» Start of TS 38.413 implementation exampl C<<<<<<<<<<<<<<<<<9.2.6.1 NG SETUP REQUESTThis message is sent by the NG-RAN node to transfer application layer information for an NG-C interface instance.Direction: NG-RAN node9,3,1.x UE Contexts to be Retrieved This IE indicates the list of UE contexts to be retrieved from another AMF and the identifier of the A MF,»»»»»»»»»»End of TS 38.413 implementation exampl C<<<<<<<<<<<<<<<<<

[0150] Another non-limiting implementation examples in TS 38.413 vl8.0.0 is shown below. In this example, a separate non-UE-associated message is used to trigger UE context retrieval from another AMF. New parts are shown via underlined text.»»»»»»»»»» Start of TS 38.413 implementation exampl C<<<<<<<<<<<<<<<<<9,2 6.x RETRIEVE UE CONTEXTS This message is sent by the NG-RAN node to trigger retrieval of UE contexts from another AMF,Direction: NG-RAN node AMF»»»»»»»»»»End of TS 38.413 implementation exampl C<<<<<<<<<<<<<<<<<

[0151] Another non-limiting implementation examples in TS 38.413 vl8.0.0 is shown below. In this example, a separate non-UE-associated message is used to trigger UE context transfer to another AMF. The new parts are shown in underlined text.»»»»»»»»»» Start of TS 38.413 implementation exampl C<<<<<<<<<<<<<<<<<9,2 6.x TRANSFER UE CONTEXTS This message is sent by the NG-RAN node to trigger transfer of UE contexts to another AMF,Direction: NG-RAN node AMF»»»»»»»»»»End of TS 38.413 implementation exampl C<<<<<<<<<<<<<<<<<

[0152] Another non-limiting implementation examples in TS 38.413 vl8.0.0 is shown below. In this example, a separate UE-associated message is used to transfer of a particular UE context to another AMF. The new parts are shown in underlined text.»»»»»»»»»» Start of TS 38.413 implementation exampl C<<<<<<<<<<<<<<<<<9 2 2.x TRANSFER UE CONTEXTThis message is sent by the NG-RAN node to trigger transfer of UE context to another AMF for a particular UE,Direction: NG-RAN node AMF»»»»»»»»»»End of TS 38.413 implementation exampl C<<<<<<<<<<<<<<<<<

[0153] Another non-limiting implementation examples in TS 38.413 vl8.0.0 is shown below. The new parts are shown via underlined text.

[0154] In the example below, an IE is proposed to set up the data forwarding between the source WAB-gNB and the Target CN / Target BH in Handover procedure. In this example, when the Target WAB-gNB accepts the data forwarding, the data forwarding tunnels are set up between the source WAB-gNB and the target CN / target BH.»»»»»»»»»» Start of TS 38.413 implementation exampl C<<<<<<<<<<<<<<<<<9.3.4.14 Handover Required Transfer»»»»»»»»»»End of TS 38.413 implementation exampl C<<<<<<<<<<<<<<<<<

[0155] Another non-limiting implementation examples in TS 38.413 vl8.0.0 is shown below.The new parts are shown in underlined text.

[0156] In the example below, an IE is proposed to set up the data forwarding between the source WAB-gNB and the Target CN. In this example, the Target WAB-gNB accepts the data forwarding, and indicates to the target CN to provide the data forwarding tunnels. Upon the reception, the source WAB-gNB repacks the data to be forwarded to the correct address.»»»»»»»»»» Start of TS 38.413 implementation exampl C<<<<<<<<<<<<<<<<< 9.3.4.11 Handover Request Acknowledge Transfer»»»»»»»»»»End of TS 38.413 implementation exampl C<<<<<<<<<<<<<<<<<

[0157] Figure 8 shows an example of a communication system 800 in accordance with some embodiments. In the example, the communication system 800 includes a telecommunication network 802 that includes an access network 804, such as a radio access network (RAN), and a core network 806, which includes one or more core network nodes 808. The access network 804 includes one or more access network nodes, such as network nodes 810a and 810b (one or more of which may be generally referred to as network nodes 810), or any other similar 3rd Generation Partnership Project (3 GPP) access node or non-3GPP access point. The network nodes 810 facilitate direct or indirect connection of user equipment (UE), such as by connecting UEs 812a, 812b, 812c, and 812d (one or more of which may be generally referred to as UEs 812) to the core network 806 over one or more wireless connections.

[0158] Example wireless communications over a wireless connection include transmitting and / or receiving wireless signals using electromagnetic waves, radio waves, infrared waves, and / or other types of signals suitable for conveying information without the use of wires, cables, or other material conductors. Moreover, in different embodiments, the communication system 800 may include any number of wired or wireless networks, network nodes, UEs, and / or any other components or systems that may facilitate or participate in the communication of data and / or signals whether via wired or wireless connections. The communication system 800 may includeand / or interface with any type of communication, telecommunication, data, cellular, radio network, and / or other similar type of system.

[0159] The UEs 812 may be any of a wide variety of communication devices, including wireless devices arranged, configured, and / or operable to communicate wirelessly with the network nodes 810 and other communication devices. Similarly, the network nodes 810 are arranged, capable, configured, and / or operable to communicate directly or indirectly with the UEs 812 and / or with other network nodes or equipment in the telecommunication network 802 to enable and / or provide network access, such as wireless network access, and / or to perform other functions, such as administration in the telecommunication network 802.

[0160] In the depicted example, the core network 806 connects the network nodes 810 to one or more hosts, such as host 816. These connections may be direct or indirect via one or more intermediary networks or devices. In other examples, network nodes may be directly coupled to hosts. The core network 806 includes one more core network nodes (e.g., core network node 808) that are structured with hardware and software components. Features of these components may be substantially similar to those described with respect to the UEs, network nodes, and / or hosts, such that the descriptions thereof are generally applicable to the corresponding components of the core network node 808. Example core network nodes include functions of one or more of a Mobile Switching Center (MSC), Mobility Management Entity (MME), Home Subscriber Server (HSS), Access and Mobility Management Function (AMF), Session Management Function (SMF), Authentication Server Function (AUSF), Subscription Identifier De-concealing function (SIDF), Unified Data Management (UDM), Security Edge Protection Proxy (SEPP), Network Exposure Function (NEF), and / or a User Plane Function (UPF).

[0161] The host 816 may be under the ownership or control of a service provider other than an operator or provider of the access network 804 and / or the telecommunication network 802, and may be operated by the service provider or on behalf of the service provider. The host 816 may host a variety of applications to provide one or more service. Examples of such applications include live and pre-recorded audio / video content, data collection services such as retrieving and compiling data on various ambient conditions detected by a plurality of UEs, analytics functionality, social media, functions for controlling or otherwise interacting with remote devices, functions for an alarm and surveillance center, or any other such function performed by a server.

[0162] As a whole, the communication system 800 of Figure 8 enables connectivity between the UEs, network nodes, and hosts. In that sense, the communication system may be configured to operate according to predefined rules or procedures, such as specific standards that include, but are not limited to: Global System for Mobile Communications (GSM); Universal MobileTelecommunications System (UMTS); Long Term Evolution (LTE), and / or other suitable 2G, 3G, 4G, 5G standards, or any applicable future generation standard (e.g., 6G); wireless local area network (WLAN) standards, such as the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards (WiFi); and / or any other appropriate wireless communication standard, such as the Worldwide Interoperability for Microwave Access (WiMax), Bluetooth, Z-Wave, Near Field Communication (NFC) ZigBee, LiFi, and / or any low-power wide-area network (LPWAN) standards such as LoRa and Sigfox.

[0163] In some examples, the telecommunication network 802 is a cellular network that implements 3GPP standardized features. Accordingly, the telecommunications network 802 may support network slicing to provide different logical networks to different devices that are connected to the telecommunication network 802. For example, the telecommunications network 802 may provide Ultra Reliable Low Latency Communication (URLLC) services to some UEs, while providing Enhanced Mobile Broadband (eMBB) services to other UEs, and / or Massive Machine Type Communication (mMTC) / Massive loT services to yet further UEs.

[0164] In some examples, the UEs 812 are configured to transmit and / or receive information without direct human interaction. For instance, a UE may be designed to transmit information to the access network 804 on a predetermined schedule, when triggered by an internal or external event, or in response to requests from the access network 804. Additionally, a UE may be configured for operating in single- or multi -RAT or multi-standard mode. For example, a UE may operate with any one or combination of Wi-Fi, NR (New Radio) and LTE, i.e. being configured for multi -radio dual connectivity (MR-DC), such as E-UTRAN (Evolved-UMTS Terrestrial Radio Access Network) New Radio - Dual Connectivity (EN-DC).

[0165] In the example, the hub 814 communicates with the access network 804 to facilitate indirect communication between one or more UEs (e.g., UE 812c and / or 812d) and network nodes (e.g., network node 810b). In some examples, the hub 814 may be a controller, router, content source and analytics, or any of the other communication devices described herein regarding UEs. For example, the hub 814 may be a broadband router enabling access to the core network 806 for the UEs. As another example, the hub 814 may be a controller that sends commands or instructions to one or more actuators in the UEs. Commands or instructions may be received from the UEs, network nodes 810, or by executable code, script, process, or other instructions in the hub 814. As another example, the hub 814 may be a data collector that acts as temporary storage for UE data and, in some embodiments, may perform analysis or other processing of the data. As another example, the hub 814 may be a content source. For example, for a UE that is a VR headset, display, loudspeaker or other media delivery device, the hub 814 may retrieve VR assets, video, audio, orother media or data related to sensory information via a network node, which the hub 814 then provides to the UE either directly, after performing local processing, and / or after adding additional local content. In still another example, the hub 814 acts as a proxy server or orchestrator for the UEs, in particular in if one or more of the UEs are low energy loT devices.

[0166] The hub 814 may have a constant / persistent or intermittent connection to the network node 810b. The hub 814 may also allow for a different communication scheme and / or schedule between the hub 814 and UEs (e.g., UE 812c and / or 812d), and between the hub 814 and the core network 806. In other examples, the hub 814 is connected to the core network 806 and / or one or more UEs via a wired connection. Moreover, the hub 814 may be configured to connect to an M2M service provider over the access network 804 and / or to another UE over a direct connection. In some scenarios, UEs may establish a wireless connection with the network nodes 810 while still connected via the hub 814 via a wired or wireless connection. In some embodiments, the hub 814 may be a dedicated hub - that is, a hub whose primary function is to route communications to / from the UEs from / to the network node 810b. In other embodiments, the hub 814 may be a nondedicated hub - that is, a device which is capable of operating to route communications between the UEs and network node 810b, but which is additionally capable of operating as a communication start and / or end point for certain data channels.

[0167] Figure 9 shows a UE 900 in accordance with some embodiments. As used herein, a UE refers to a device capable, configured, arranged and / or operable to communicate wirelessly with network nodes and / or other UEs. Examples of a UE include, but are not limited to, a smart phone, mobile phone, cell phone, voice over IP (VoIP) phone, wireless local loop phone, desktop computer, personal digital assistant (PDA), wireless cameras, gaming console or device, music storage device, playback appliance, wearable terminal device, wireless endpoint, mobile station, tablet, laptop, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), smart device, wireless customer-premise equipment (CPE), vehicle-mounted or vehicle embedded / integrated wireless device, etc. Other examples include any UE identified by the 3rd Generation Partnership Project (3 GPP), including a narrow band internet of things (NB-IoT) UE, a machine type communication (MTC) UE, and / or an enhanced MTC (eMTC) UE.

[0168] A UE may support device-to-device (D2D) communication, for example by implementing a 3 GPP standard for sidelink communication, Dedicated Short-Range Communication (DSRC), vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), or vehicle-to- everything (V2X). In other examples, a UE may not necessarily have a user in the sense of a human user who owns and / or operates the relevant device. Instead, a UE may represent a device that is intended for sale to, or operation by, a human user but which may not, or which may not initially,be associated with a specific human user (e.g., a smart sprinkler controller). Alternatively, a UE may represent a device that is not intended for sale to, or operation by, an end user but which may be associated with or operated for the benefit of a user (e.g., a smart power meter).

[0169] The UE 900 includes processing circuitry 902 that is operatively coupled via a bus 904 to an input / output interface 906, a power source 908, a memory 910, a communication interface 912, and / or any other component, or any combination thereof. Certain UEs may utilize all or a subset of the components shown in Figure 9. The level of integration between the components may vary from one UE to another UE. Further, certain UEs may contain multiple instances of a component, such as multiple processors, memories, transceivers, transmitters, receivers, etc.

[0170] The processing circuitry 902 is configured to process instructions and data and may be configured to implement any sequential state machine operative to execute instructions stored as machine-readable computer programs in the memory 910. The processing circuitry 902 may be implemented as one or more hardware-implemented state machines (e.g., in discrete logic, field- programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), etc.); programmable logic together with appropriate firmware; one or more stored computer programs, general-purpose processors, such as a microprocessor or digital signal processor (DSP), together with appropriate software; or any combination of the above. For example, the processing circuitry 902 may include multiple central processing units (CPUs).

[0171] In the example, the input / output interface 906 may be configured to provide an interface or interfaces to an input device, output device, or one or more input and / or output devices. Examples of an output device include a speaker, a sound card, a video card, a display, a monitor, a printer, an actuator, an emitter, a smartcard, another output device, or any combination thereof. An input device may allow a user to capture information into the UE 900. Examples of an input device include a touch-sensitive or presence-sensitive display, a camera (e.g., a digital camera, a digital video camera, a web camera, etc.), a microphone, a sensor, a mouse, a trackball, a directional pad, a trackpad, a scroll wheel, a smartcard, and the like. The presence-sensitive display may include a capacitive or resistive touch sensor to sense input from a user. A sensor may be, for instance, an accelerometer, a gyroscope, a tilt sensor, a force sensor, a magnetometer, an optical sensor, a proximity sensor, a biometric sensor, etc., or any combination thereof. An output device may use the same type of interface port as an input device. For example, a Universal Serial Bus (USB) port may be used to provide an input device and an output device.

[0172] In some embodiments, the power source 908 is structured as a battery or battery pack. Other types of power sources, such as an external power source (e.g., an electricity outlet), photovoltaic device, or power cell, may be used. The power source 908 may further include powercircuitry for delivering power from the power source 908 itself, and / or an external power source, to the various parts of the UE 900 via input circuitry or an interface such as an electrical power cable. Delivering power may be, for example, for charging of the power source 908. Power circuitry may perform any formatting, converting, or other modification to the power from the power source 908 to make the power suitable for the respective components of the UE 900 to which power is supplied.

[0173] The memory 910 may be or be configured to include memory such as random access memory (RAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), magnetic disks, optical disks, hard disks, removable cartridges, flash drives, and so forth. In one example, the memory 910 includes one or more application programs 914, such as an operating system, web browser application, a widget, gadget engine, or other application, and corresponding data 916. The memory 910 may store, for use by the UE 900, any of a variety of various operating systems or combinations of operating systems.

[0174] The memory 910 may be configured to include a number of physical drive units, such as redundant array of independent disks (RAID), flash memory, USB flash drive, external hard disk drive, thumb drive, pen drive, key drive, high-density digital versatile disc (HD-DVD) optical disc drive, internal hard disk drive, Blu-Ray optical disc drive, holographic digital data storage (HDDS) optical disc drive, external mini-dual in-line memory module (DIMM), synchronous dynamic random access memory (SDRAM), external micro-DIMM SDRAM, smartcard memory such as tamper resistant module in the form of a universal integrated circuit card (UICC) including one or more subscriber identity modules (SIMs), such as a USIM and / or ISIM, other memory, or any combination thereof. The UICC may for example be an embedded UICC (eUICC), integrated UICC (iUICC) or a removable UICC commonly known as ‘SIM card.’ The memory 910 may allow the UE 900 to access instructions, application programs and the like, stored on transitory or non-transitory memory media, to off-load data, or to upload data. An article of manufacture, such as one utilizing a communication system may be tangibly embodied as or in the memory 910, which may be or comprise a device-readable storage medium.

[0175] The processing circuitry 902 may be configured to communicate with an access network or other network using the communication interface 912. The communication interface 912 may comprise one or more communication subsystems and may include or be communicatively coupled to an antenna 922. The communication interface 912 may include one or more transceivers used to communicate, such as by communicating with one or more remote transceivers of another device capable of wireless communication (e.g., another UE or a networknode in an access network). Each transceiver may include a transmitter 918 and / or a receiver 920 appropriate to provide network communications (e.g., optical, electrical, frequency allocations, and so forth). Moreover, the transmitter 918 and receiver 920 may be coupled to one or more antennas (e.g., antenna 922) and may share circuit components, software or firmware, or alternatively be implemented separately.

[0176] In the illustrated embodiment, communication functions of the communication interface 912 may include cellular communication, Wi-Fi communication, LPWAN communication, data communication, voice communication, multimedia communication, short- range communications such as Bluetooth, near-field communication, location-based communication such as the use of the global positioning system (GPS) to determine a location, another like communication function, or any combination thereof. Communications may be implemented in according to one or more communication protocols and / or standards, such as IEEE 802.11, Code Division Multiplexing Access (CDMA), Wideband Code Division Multiple Access (WCDMA), GSM, LTE, New Radio (NR), UMTS, WiMax, Ethernet, transmission control protocol / intemet protocol (TCP / IP), synchronous optical networking (SONET), Asynchronous Transfer Mode (ATM), QUIC, Hypertext Transfer Protocol (HTTP), and so forth.

[0177] Regardless of the type of sensor, a UE may provide an output of data captured by its sensors, through its communication interface 912, via a wireless connection to a network node. Data captured by sensors of a UE can be communicated through a wireless connection to a network node via another UE. The output may be periodic (e.g., once every 15 minutes if it reports the sensed temperature), random (e.g., to even out the load from reporting from several sensors), in response to a triggering event (e.g., when moisture is detected, an alert is sent), in response to a request (e.g., a user initiated request), or a continuous stream (e.g., a live video feed of a patient).

[0178] As another example, a UE comprises an actuator, a motor, or a switch, related to a communication interface configured to receive wireless input from a network node via a wireless connection. In response to the received wireless input the states of the actuator, the motor, or the switch may change. For example, the UE may comprise a motor that adjusts the control surfaces or rotors of a drone in flight according to the received input or to a robotic arm performing a medical procedure according to the received input.

[0179] A UE, when in the form of an Internet of Things (loT) device, may be a device for use in one or more application domains, these domains comprising, but not limited to, city wearable technology, extended industrial application and healthcare. Non-limiting examples of such an loT device are a device which is or which is embedded in: a connected refrigerator or freezer, a TV, a connected lighting device, an electricity meter, a robot vacuum cleaner, a voice controlled smartspeaker, a home security camera, a motion detector, a thermostat, a smoke detector, a door / window sensor, a flood / moisture sensor, an electrical door lock, a connected doorbell, an air conditioning system like a heat pump, an autonomous vehicle, a surveillance system, a weather monitoring device, a vehicle parking monitoring device, an electric vehicle charging station, a smart watch, a fitness tracker, a head-mounted display for Augmented Reality (AR) or Virtual Reality (VR), a wearable for tactile augmentation or sensory enhancement, a water sprinkler, an animal- or itemtracking device, a sensor for monitoring a plant or animal, an industrial robot, an Unmanned Aerial Vehicle (UAV), and any kind of medical device, like a heart rate monitor or a remote controlled surgical robot. A UE in the form of an loT device comprises circuitry and / or software in dependence of the intended application of the loT device in addition to other components as described in relation to the UE 900 shown in Figure 9.

[0180] As yet another specific example, in an loT scenario, a UE may represent a machine or other device that performs monitoring and / or measurements, and transmits the results of such monitoring and / or measurements to another UE and / or a network node. The UE may in this case be an M2M device, which may in a 3GPP context be referred to as an MTC device. As one particular example, the UE may implement the 3 GPP NB-IoT standard. In other scenarios, a UE may represent a vehicle, such as a car, a bus, a truck, a ship and an airplane, or other equipment that is capable of monitoring and / or reporting on its operational status or other functions associated with its operation.

[0181] In practice, any number of UEs may be used together with respect to a single use case. For example, a first UE might be or be integrated in a drone and provide the drone’s speed information (obtained through a speed sensor) to a second UE that is a remote controller operating the drone. When the user makes changes from the remote controller, the first UE may adjust the throttle on the drone (e.g. by controlling an actuator) to increase or decrease the drone’s speed. The first and / or the second UE can also include more than one of the functionalities described above. For example, a UE might comprise the sensor and the actuator, and handle communication of data for both the speed sensor and the actuators.

[0182] Figure 10 shows a network node 1000 in accordance with some embodiments. As used herein, network node refers to equipment capable, configured, arranged and / or operable to communicate directly or indirectly with a UE and / or with other network nodes or equipment, in a telecommunication network. Examples of network nodes include, but are not limited to, access points (APs) (e.g., radio access points), base stations (BSs) (e.g., radio base stations, Node Bs, evolved Node Bs (eNBs) and NR NodeBs (gNBs)).

[0183] Base stations may be categorized based on the amount of coverage they provide (or, stated differently, their transmit power level) and so, depending on the provided amount of coverage, may be referred to as femto base stations, pico base stations, micro base stations, or macro base stations. A base station may be a relay node or a relay donor node controlling a relay. A network node may also include one or more (or all) parts of a distributed radio base station such as centralized digital units and / or remote radio units (RRUs), sometimes referred to as Remote Radio Heads (RRHs). Such remote radio units may or may not be integrated with an antenna as an antenna integrated radio. Parts of a distributed radio base station may also be referred to as nodes in a distributed antenna system (DAS).

[0184] Other examples of network nodes include multiple transmission point (multi-TRP) 5G access nodes, multi-standard radio (MSR) equipment such as MSR BSs, network controllers such as radio network controllers (RNCs) or base station controllers (BSCs), base transceiver stations (BTSs), transmission points, transmission nodes, multi-cell / multicast coordination entities (MCEs), Operation and Maintenance (O&M) nodes, Operations Support System (OSS) nodes, Self-Organizing Network (SON) nodes, positioning nodes (e.g., Evolved Serving Mobile Location Centers (E-SMLCs)), and / or Minimization of Drive Tests (MDTs).

[0185] The network node 1000 includes a processing circuitry 1002, a memory 1004, a communication interface 1006, and a power source 1008. The network node 1000 may be composed of multiple physically separate components (e.g., a NodeB component and a RNC component, or a BTS component and a BSC component, etc.), which may each have their own respective components. In certain scenarios in which the network node 1000 comprises multiple separate components (e.g., BTS and BSC components), one or more of the separate components may be shared among several network nodes. For example, a single RNC may control multiple NodeB s. In such a scenario, each unique NodeB and RNC pair, may in some instances be considered a single separate network node. In some embodiments, the network node 1000 may be configured to support multiple radio access technologies (RATs). In such embodiments, some components may be duplicated (e.g., separate memory 1004 for different RATs) and some components may be reused (e.g., a same antenna 1010 may be shared by different RATs). The network node 1000 may also include multiple sets of the various illustrated components for different wireless technologies integrated into network node 1000, for example GSM, WCDMA, LTE, NR, WiFi, Zigbee, Z-wave, LoRaWAN, Radio Frequency Identification (RFID) or Bluetooth wireless technologies. These wireless technologies may be integrated into the same or different chip or set of chips and other components within network node 1000.

[0186] The processing circuitry 1002 may comprise a combination of one or more of a microprocessor, controller, microcontroller, central processing unit, digital signal processor, application-specific integrated circuit, field programmable gate array, or any other suitable computing device, resource, or combination of hardware, software and / or encoded logic operable to provide, either alone or in conjunction with other network node 1000 components, such as the memory 1004, to provide network node 1000 functionality.

[0187] In some embodiments, the processing circuitry 1002 includes a system on a chip (SOC). In some embodiments, the processing circuitry 1002 includes one or more of radio frequency (RF) transceiver circuitry 1012 and baseband processing circuitry 1014. In some embodiments, the radio frequency (RF) transceiver circuitry 1012 and the baseband processing circuitry 1014 may be on separate chips (or sets of chips), boards, or units, such as radio units and digital units. In alternative embodiments, part or all of RF transceiver circuitry 1012 and baseband processing circuitry 1014 may be on the same chip or set of chips, boards, or units.

[0188] The memory 1004 may comprise any form of volatile or non-volatile computer- readable memory including, without limitation, persistent storage, solid-state memory, remotely mounted memory, magnetic media, optical media, random access memory (RAM), read-only memory (ROM), mass storage media (for example, a hard disk), removable storage media (for example, a flash drive, a Compact Disk (CD) or a Digital Video Disk (DVD)), and / or any other volatile or non-volatile, non-transitory device-readable and / or computer-executable memory devices that store information, data, and / or instructions that may be used by the processing circuitry 1002. The memory 1004 may store any suitable instructions, data, or information, including a computer program, software, an application including one or more of logic, rules, code, tables, and / or other instructions capable of being executed by the processing circuitry 1002 and utilized by the network node 1000. The memory 1004 may be used to store any calculations made by the processing circuitry 1002 and / or any data received via the communication interface 1006. In some embodiments, the processing circuitry 1002 and memory 1004 is integrated.

[0189] The communication interface 1006 is used in wired or wireless communication of signaling and / or data between a network node, access network, and / or UE. As illustrated, the communication interface 1006 comprises port(s) / terminal(s) 1016 to send and receive data, for example to and from a network over a wired connection. The communication interface 1006 also includes radio front-end circuitry 1018 that may be coupled to, or in certain embodiments a part of, the antenna 1010. Radio front-end circuitry 1018 comprises filters 1020 and amplifiers 1022. The radio front-end circuitry 1018 may be connected to an antenna 1010 and processing circuitry 1002. The radio front-end circuitry may be configured to condition signals communicated betweenantenna 1010 and processing circuitry 1002. The radio front-end circuitry 1018 may receive digital data that is to be sent out to other network nodes or UEs via a wireless connection. The radio frontend circuitry 1018 may convert the digital data into a radio signal having the appropriate channel and bandwidth parameters using a combination of filters 1020 and / or amplifiers 1022. The radio signal may then be transmitted via the antenna 1010. Similarly, when receiving data, the antenna 1010 may collect radio signals which are then converted into digital data by the radio front-end circuitry 1018. The digital data may be passed to the processing circuitry 1002. In other embodiments, the communication interface may comprise different components and / or different combinations of components.

[0190] In certain alternative embodiments, the network node 1000 does not include separate radio front-end circuitry 1018, instead, the processing circuitry 1002 includes radio front-end circuitry and is connected to the antenna 1010. Similarly, in some embodiments, all or some of the RF transceiver circuitry 1012 is part of the communication interface 1006. In still other embodiments, the communication interface 1006 includes one or more ports or terminals 1016, the radio front-end circuitry 1018, and the RF transceiver circuitry 1012, as part of a radio unit (not shown), and the communication interface 1006 communicates with the baseband processing circuitry 1014, which is part of a digital unit (not shown).

[0191] The antenna 1010 may include one or more antennas, or antenna arrays, configured to send and / or receive wireless signals. The antenna 1010 may be coupled to the radio front-end circuitry 1018 and may be any type of antenna capable of transmitting and receiving data and / or signals wirelessly. In certain embodiments, the antenna 1010 is separate from the network node 1000 and connectable to the network node 1000 through an interface or port.

[0192] The antenna 1010, communication interface 1006, and / or the processing circuitry 1002 may be configured to perform any receiving operations and / or certain obtaining operations described herein as being performed by the network node. Any information, data and / or signals may be received from a UE, another network node and / or any other network equipment. Similarly, the antenna 1010, the communication interface 1006, and / or the processing circuitry 1002 may be configured to perform any transmitting operations described herein as being performed by the network node. Any information, data and / or signals may be transmitted to a UE, another network node and / or any other network equipment.

[0193] The power source 1008 provides power to the various components of network node 1000 in a form suitable for the respective components (e.g., at a voltage and current level needed for each respective component). The power source 1008 may further comprise, or be coupled to, power management circuitry to supply the components of the network node 1000 with power forperforming the functionality described herein. For example, the network node 1000 may be connectable to an external power source (e.g., the power grid, an electricity outlet) via an input circuitry or interface such as an electrical cable, whereby the external power source supplies power to power circuitry of the power source 1008. As a further example, the power source 1008 may comprise a source of power in the form of a battery or battery pack which is connected to, or integrated in, power circuitry. The battery may provide backup power should the external power source fail.

[0194] Embodiments of the network node 1000 may include additional components beyond those shown in Figure 10 for providing certain aspects of the network node’s functionality, including any of the functionality described herein and / or any functionality necessary to support the subject matter described herein. For example, the network node 1000 may include user interface equipment to allow input of information into the network node 1000 and to allow output of information from the network node 1000. This may allow a user to perform diagnostic, maintenance, repair, and other administrative functions for the network node 1000.

[0195] Figure 11 is a block diagram of a host 1100, which may be an embodiment of the host 816 of Figure 8, in accordance with various aspects described herein. As used herein, the host 1100 may be or comprise various combinations of hardware and / or software, including a standalone server, a blade server, a cloud-implemented server, a distributed server, a virtual machine, container, or processing resources in a server farm. The host 1100 may provide one or more services to one or more UEs.

[0196] The host 1100 includes processing circuitry 1102 that is operatively coupled via a bus 1104 to an input / output interface 1106, a network interface 1108, a power source 1110, and a memory 1112. Other components may be included in other embodiments. Features of these components may be substantially similar to those described with respect to the devices of previous figures, such as Figures 9 and 10, such that the descriptions thereof are generally applicable to the corresponding components of host 1100.

[0197] The memory 1112 may include one or more computer programs including one or more host application programs 1114 and data 1116, which may include user data, e.g., data generated by a UE for the host 1100 or data generated by the host 1100 for a UE. Embodiments of the host 1100 may utilize only a subset or all of the components shown. The host application programs 1114 may be implemented in a container-based architecture and may provide support for video codecs (e.g., Versatile Video Coding (VVC), High Efficiency Video Coding (HEVC), Advanced Video Coding (AVC), MPEG, VP9) and audio codecs (e.g., FLAC, Advanced Audio Coding (AAC), MPEG, G.711), including transcoding for multiple different classes, types, orimplementations of UEs (e.g., handsets, desktop computers, wearable display systems, heads-up display systems). The host application programs 1114 may also provide for user authentication and licensing checks and may periodically report health, routes, and content availability to a central node, such as a device in or on the edge of a core network. Accordingly, the host 1100 may select and / or indicate a different host for over-the-top services for a UE. The host application programs 1114 may support various protocols, such as the HTTP Live Streaming (HLS) protocol, Real-Time Messaging Protocol (RTMP), Real-Time Streaming Protocol (RTSP), Dynamic Adaptive Streaming over HTTP (MPEG-DASH), etc.

[0198] Figure 12 is a block diagram illustrating a virtualization environment 1200 in which functions implemented by some embodiments may be virtualized. In the present context, virtualizing means creating virtual versions of apparatuses or devices which may include virtualizing hardware platforms, storage devices and networking resources. As used herein, virtualization can be applied to any device described herein, or components thereof, and relates to an implementation in which at least a portion of the functionality is implemented as one or more virtual components. Some or all of the functions described herein may be implemented as virtual components executed by one or more virtual machines (VMs) implemented in one or more virtual environments 1200 hosted by one or more of hardware nodes, such as a hardware computing device that operates as a network node, UE, core network node, or host. Further, in embodiments in which the virtual node does not require radio connectivity (e.g., a core network node or host), then the node may be entirely virtualized.

[0199] Applications 1202 (which may alternatively be called software instances, virtual appliances, network functions, virtual nodes, virtual network functions, etc.) are run in the virtualization environment 1200 to implement some of the features, functions, and / or benefits of some of the embodiments disclosed herein.

[0200] Hardware 1204 includes processing circuitry, memory that stores software and / or instructions executable by hardware processing circuitry, and / or other hardware devices as described herein, such as a network interface, input / output interface, and so forth. Software may be executed by the processing circuitry to instantiate one or more virtualization layers 1206 (also referred to as hypervisors or virtual machine monitors (VMMs)), provide VMs 1208a and 1208b (one or more of which may be generally referred to as VMs 1208), and / or perform any of the functions, features and / or benefits described in relation with some embodiments described herein. The virtualization layer 1206 may present a virtual operating platform that appears like networking hardware to the VMs 1208.

[0201] The VMs 1208 comprise virtual processing, virtual memory, virtual networking or interface and virtual storage, and may be run by a corresponding virtualization layer 1206. Different embodiments of the instance of a virtual appliance 1202 may be implemented on one or more of VMs 1208, and the implementations may be made in different ways. Virtualization of the hardware is in some contexts referred to as network function virtualization (NFV). NFV may be used to consolidate many network equipment types onto industry standard high volume server hardware, physical switches, and physical storage, which can be located in data centers, and customer premise equipment.

[0202] In the context of NFV, a VM 1208 may be a software implementation of a physical machine that runs programs as if they were executing on a physical, non-virtualized machine. Each of the VMs 1208, and that part of hardware 1204 that executes that VM, be it hardware dedicated to that VM and / or hardware shared by that VM with others of the VMs, forms separate virtual network elements. Still in the context of NFV, a virtual network function is responsible for handling specific network functions that run in one or more VMs 1208 on top of the hardware 1204 and corresponds to the application 1202.

[0203] Hardware 1204 may be implemented in a standalone network node with generic or specific components. Hardware 1204 may implement some functions via virtualization. Alternatively, hardware 1204 may be part of a larger cluster of hardware (e.g. such as in a data center or CPE) where many hardware nodes work together and are managed via management and orchestration 1210, which, among others, oversees lifecycle management of applications 1202. In some embodiments, hardware 1204 is coupled to one or more radio units that each include one or more transmitters and one or more receivers that may be coupled to one or more antennas. Radio units may communicate directly with other hardware nodes via one or more appropriate network interfaces and may be used in combination with the virtual components to provide a virtual node with radio capabilities, such as a radio access node or a base station. In some embodiments, some signaling can be provided with the use of a control system 1212 which may alternatively be used for communication between hardware nodes and radio units.

[0204] Figure 13 shows a communication diagram of a host 1302 communicating via a network node 1304 with a UE 1306 over a partially wireless connection in accordance with some embodiments. Example implementations, in accordance with various embodiments, of the UE (such as a UE 812a of Figure 8 and / or UE 900 of Figure 9), network node (such as network node 810a of Figure 8 and / or network node 1000 of Figure 10), and host (such as host 816 of Figure 8 and / or host 1100 of Figure 11) discussed in the preceding paragraphs will now be described with reference to Figure 13.

[0205] Like host 1100, embodiments of host 1302 include hardware, such as a communication interface, processing circuitry, and memory. The host 1302 also includes software, which is stored in or accessible by the host 1302 and executable by the processing circuitry. The software includes a host application that may be operable to provide a service to a remote user, such as the UE 1306 connecting via an over-the-top (OTT) connection 1350 extending between the UE 1306 and host 1302. In providing the service to the remote user, a host application may provide user data which is transmitted using the OTT connection 1350.

[0206] The network node 1304 includes hardware enabling it to communicate with the host 1302 and UE 1306. The connection 1360 may be direct or pass through a core network (like core network 806 of Figure 8) and / or one or more other intermediate networks, such as one or more public, private, or hosted networks. For example, an intermediate network may be a backbone network or the Internet.

[0207] The UE 1306 includes hardware and software, which is stored in or accessible by UE 1306 and executable by the UE’s processing circuitry. The software includes a client application, such as a web browser or operator-specific “app” that may be operable to provide a service to a human or non-human user via UE 1306 with the support of the host 1302. In the host 1302, an executing host application may communicate with the executing client application via the OTT connection 1350 terminating at the UE 1306 and host 1302. In providing the service to the user, the UE's client application may receive request data from the host's host application and provide user data in response to the request data. The OTT connection 1350 may transfer both the request data and the user data. The UE's client application may interact with the user to generate the user data that it provides to the host application through the OTT connection 1350.

[0208] The OTT connection 1350 may extend via a connection 1360 between the host 1302 and the network node 1304 and via a wireless connection 1370 between the network node 1304 and the UE 1306 to provide the connection between the host 1302 and the UE 1306. The connection 1360 and wireless connection 1370, over which the OTT connection 1350 may be provided, have been drawn abstractly to illustrate the communication between the host 1302 and the UE 1306 via the network node 1304, without explicit reference to any intermediary devices and the precise routing of messages via these devices.

[0209] As an example of transmitting data via the OTT connection 1350, in step 1308, the host 1302 provides user data, which may be performed by executing a host application. In some embodiments, the user data is associated with a particular human user interacting with the UE 1306. In other embodiments, the user data is associated with a UE 1306 that shares data with the host 1302 without explicit human interaction. In step 1310, the host 1302 initiates a transmissioncarrying the user data towards the UE 1306. The host 1302 may initiate the transmission responsive to a request transmitted by the UE 1306. The request may be caused by human interaction with the UE 1306 or by operation of the client application executing on the UE 1306. The transmission may pass via the network node 1304, in accordance with the teachings of the embodiments described throughout this disclosure. Accordingly, in step 1312, the network node 1304 transmits to the UE 1306 the user data that was carried in the transmission that the host 1302 initiated, in accordance with the teachings of the embodiments described throughout this disclosure. In step 1314, the UE 1306 receives the user data carried in the transmission, which may be performed by a client application executed on the UE 1306 associated with the host application executed by the host 1302.

[0210] In some examples, the UE 1306 executes a client application which provides user data to the host 1302. The user data may be provided in reaction or response to the data received from the host 1302. Accordingly, in step 1316, the UE 1306 may provide user data, which may be performed by executing the client application. In providing the user data, the client application may further consider user input received from the user via an input / output interface of the UE 1306. Regardless of the specific manner in which the user data was provided, the UE 1306 initiates, in step 1318, transmission of the user data towards the host 1302 via the network node 1304. In step 1320, in accordance with the teachings of the embodiments described throughout this disclosure, the network node 1304 receives user data from the UE 1306 and initiates transmission of the received user data towards the host 1302. In step 1322, the host 1302 receives the user data carried in the transmission initiated by the UE 1306.

[0211] In an example scenario, factory status information may be collected and analyzed by the host 1302. As another example, the host 1302 may process audio and video data which may have been retrieved from a UE for use in creating maps. As another example, the host 1302 may collect and analyze real-time data to assist in controlling vehicle congestion (e.g., controlling traffic lights). As another example, the host 1302 may store surveillance video uploaded by a UE. As another example, the host 1302 may store or control access to media content such as video, audio, VR or AR which it can broadcast, multicast or unicast to UEs. As other examples, the host 1302 may be used for energy pricing, remote control of non-time critical electrical load to balance power generation needs, location services, presentation services (such as compiling diagrams etc. from data collected from remote devices), or any other function of collecting, retrieving, storing, analyzing and / or transmitting data.

[0212] In some examples, a measurement procedure may be provided for the purpose of monitoring data rate, latency and other factors on which the one or more embodiments improve.There may further be an optional network functionality for reconfiguring the OTT connection 1350 between the host 1302 and UE 1306, in response to variations in the measurement results. The measurement procedure and / or the network functionality for reconfiguring the OTT connection may be implemented in software and hardware of the host 1302 and / or UE 1306. In some embodiments, sensors (not shown) may be deployed in or in association with other devices through which the OTT connection 1350 passes; the sensors may participate in the measurement procedure by supplying values of the monitored quantities exemplified above, or supplying values of other physical quantities from which software may compute or estimate the monitored quantities. The reconfiguring of the OTT connection 1350 may include message format, retransmission settings, preferred routing etc.; the reconfiguring need not directly alter the operation of the network node 1304. Such procedures and functionalities may be known and practiced in the art. In certain embodiments, measurements may involve proprietary UE signaling that facilitates measurements of throughput, propagation times, latency and the like, by the host 1302. The measurements may be implemented in that software causes messages to be transmitted, in particular empty or ‘dummy’ messages, using the OTT connection 1350 while monitoring propagation times, errors, etc.

[0213] Although the computing devices described herein (e.g., UEs, network nodes, hosts) may include the illustrated combination of hardware components, other embodiments may comprise computing devices with different combinations of components. It is to be understood that these computing devices may comprise any suitable combination of hardware and / or software needed to perform the tasks, features, functions and methods disclosed herein. Determining, calculating, obtaining or similar operations described herein may be performed by processing circuitry, which may process information by, for example, converting the obtained information into other information, comparing the obtained information or converted information to information stored in the network node, and / or performing one or more operations based on the obtained information or converted information, and as a result of said processing making a determination. Moreover, while components are depicted as single boxes located within a larger box, or nested within multiple boxes, in practice, computing devices may comprise multiple different physical components that make up a single illustrated component, and functionality may be partitioned between separate components. For example, a communication interface may be configured to include any of the components described herein, and / or the functionality of the components may be partitioned between the processing circuitry and the communication interface. In another example, non-computationally intensive functions of any of such components may beimplemented in software or firmware and computationally intensive functions may be implemented in hardware.

[0214] In certain embodiments, some or all of the functionality described herein may be provided by processing circuitry executing instructions stored on in memory, which in certain embodiments may be a computer program product in the form of a non-transitory computer- readable storage medium. In alternative embodiments, some or all of the functionality may be provided by the processing circuitry without executing instructions stored on a separate or discrete device-readable storage medium, such as in a hard-wired manner. In any of those particular embodiments, whether executing instructions stored on a non-transitory computer-readable storage medium or not, the processing circuitry can be configured to perform the described functionality. The benefits provided by such functionality are not limited to the processing circuitry alone or to other components of the computing device, but are enjoyed by the computing device as a whole, and / or by end users and a wireless network generally.

Claims

CLAIMS1. A method performed by a first base station part of a Wireless Access and Backhaul, WAB, node, the method comprising: determining (500; 600; 700) that a connection change of the first base station part of the WAB node from a first Access and Mobility Management Function, AMF, to a second AMF in a same or different Public Land Mobile Network, PLMN, is needed; and performing (502-506; 602-606; 702-704) actions that cause a connection change from the first AMF to the second AMF and handle User Equipment, UE, mobility in association with the connection change from the first AMF to the second AMF.

2. The method of claim 1, wherein performing (502-506; 602-606; 702-704) actions that cause the connection change from the first AMF to the second AMF and handle UE mobility in association with the connection change from the first AMF to the second AMF comprises: instantiating a second logical base station part of a WAB node that connects to the second AMF and operates a target cell for handover of UEs served by a source cell operated by the first base station part of a WAB node; and performing (506) one or more actions related to handling of connectivity of one or more UEs in relation to the instantiation of the second base station part of a WAB node connected to the second AMF.

3. The method of claim 2, wherein the second logical base station part of a WAB is configured with new configuration parameters used to establish a connection to the second AMF and to operate the target cell.

4. The method of claim 2, wherein the first AMF and the second AMF are different AMFs, in a same PLMN.

5. The method of claim 4, wherein one or more parameters for operation of the second base station part of a WAB node connected to the second AMF are changed, relative to corresponding one or more parameters for operation of the first base station part of a WAB connected to the first AMF, in such a way that one or more UEs served by the first base station part of a WAB node are impacted.

6. The method of claim 5, wherein the one or more UEs comprise one or more UEs in a connected state, and performing (506) the one or more actions related to handling of connectivity of the one or more UEs comprises triggering (506 A) a handover of the one or more UEs in the connected state from a first cell operated by the first base station part of a WAB node to a second cell operated by the second base station part of a WAB node.

7. The method of claim 6, wherein the handover of the one or more UEs in the connected state is either NG-based or Xn-based.

8. The method of claim 5 or 6, wherein the one or more UEs comprise one or more UEs in an idle state, and a Tracking Area Code, TAC, broadcasted on the second cell operated by the second base station part of a WAB node is different than a TAC broadcasted on the first cell operated by the first base station part of a WAB node.

9. The method of any of claims 5 to 7, wherein the one or more UEs comprise one or more UEs in an inactive state, and a Tracking Area Code, TAC, and / or Radio Access Network, RAN, Notification Area Code, RANAC, broadcasted on the second cell operated by the second base station part of a WAB node is different than a TAC and / or RANAC broadcasted on the first cell operated by the first base station part of a WAB node.

10. The method of any of claims 2 to 9, wherein the first base station part removes its connection with the first AMF.

11. The method of claim 10, wherein after removing its connection with the first AMF and handover of the UEs in the connected state, the first base station part shuts down.

12. The method of claim 1, wherein performing (502-506; 602-606; 702-704) actions that cause the connection change from the first AMF to the second AMF and handle UE mobility in association with the connection change from the first AMF to the second AMF comprises: obtaining (502; 602; 702) one or more configuration parameters needed to establish a connection to the second AMF; establishing (504; 604; 704) a connection to the second AMF, based on the one or more configuration parameters; andperforming (506; 606; 704) one or more actions related to handling of connectivity of one or more UEs served by the first base station part of the WAB node in relation to movement of the first base station part of the WAB node from the first AMF to the second AMF.

13. The method of claim 12, wherein the first AMF and the second AMF are different AMFs, in a same PLMN.

14. The method of claim 13, wherein upon movement of the first base station part of the WAB node from the first AMF to the second AMF, one or more parameters for operation of the first base station part of the WAB node are changed in such a way that the one or more UEs served by the first base station part of the WAB node are impacted.

15. The method of claim 14, wherein the one or more UEs comprise one or more UEs in a connected state, and performing (506) the one or more actions comprises triggering (506A) a handover of the one or more UEs in the connected state within the first base station part of the WAB node.

16. The method of claim 14 or 15, wherein the one or more UEs comprise one or more UEs in an idle state, and performing (506) the one or more actions comprises broadcasting (506B) a Tracking Area Code, TAC, associated to the second AMF.

17. The method of any of claims 14 to 16, wherein the one or more UEs comprise one or more UEs in an inactive state, and performing (506) the one or more actions comprises broadcasting (506B) a Tracking Area Code, TAC, and / or Radio Access Network, RAN, Notification Area Code, RANAC, associated to the second AMF.

18. The method of claim 13, wherein upon movement of the first base station part of the WAB node from the first AMF to the second AMF, at least some parameters for operation of the first base station part of the WAB node remain the same after the connection change in such a way that the one or more UEs served by the first base station part of the WAB are not affected by the connection change.

19. The method of claim 18, wherein performing (606) the one or more actions comprises triggering (606) transfer of UE contexts of the one or more UEs from the first AMF to the second AMF.

20. The method of claim 18, wherein performing (606) the one or more actions comprises sending (606A-1), to the first AMF, one or more indications to transfer UE contexts of the one or more UEs to the second AMF.

21. The method of claim 18, wherein performing (606) the one or more actions comprises sending (606B), to the second AMF, one or more indications to fetch UE contexts of the one or more UEs from the first AMF.

22. The method of claim 18, wherein performing (606) the one or more actions comprises triggering release of all connected UEs such transition of the connected UEs to an idle mode.

23. The method of claim 12, wherein the first AMF is in a first PLMN, and the second AMF is in a second PLMN that is different than the first PLMN.

24. The method of claim 23, wherein performing (704) the one or more actions comprises sending (704) to the one or more UEs an indication for the one or more UEs to transition to an idle state.

25. The method of any of claims 12 to 24, wherein the first base station part removes its connection with the first AMF.

26. The method of any of claims 1 to 25, wherein determining (500; 600; 700) that the connection change from the first AMF to the second AMF is needed comprises determining (500; 600; 700) that the connection change from the first AMF to the second AMF is needed based on a current location of the first base station part of the WAB node.

27. The method of any of claims 1 to 25, wherein determining (500; 600; 700) that the connection change from the first AMF to the second AMF is needed comprises determining (500; 600; 700) that the connection change from the first AMF to the second AMF is neededbased on a current location of the first base station part of the WAB node and / or one or more additional criteria.

28. A first base station part of a Wireless Access and Backhaul, WAB, node adapted to: determine (500; 600; 700) that a connection change of the first base station part from a first Access and Mobility Management Function, AMF, to a second AMF in a same or different Public Land Mobile Network, PLMN, is needed; and perform (502-506; 602-606; 702-704) actions that cause a connection change from the first AMF to the second AMF and handle User Equipment, UE, mobility in association with the connection change from the first AMF to the second AMF.

29. The first base station part of a WAB node of claim 28, wherein in order to perform (502, 504, 506) actions that cause the connection change from the first AMF to the second AMF and handle UE mobility in association with the connection change from the first AMF to the second AMF, the first base station part of a WAB is further adapted to: instantiate a second logical base station part of a WAB node that connects to the second AMF and operates a target cell for handover of UEs served by a source cell operated by the first base station part of a WAB node; perform (506) one or more actions related to handling of connectivity of one or more UEs in relation to the instantiation of the second base station part of a WAB node connected to the second AMF.

30. The method of claim 29, wherein the second logical base station part of a WAB is configured with new configuration parameters used to establish a connection to the second AMF and to operate the target cell.

31. The first base station part of a WAB node of claim 28, wherein in order to perform (502, 504, 506) actions that cause the connection change from the first AMF to the second AMF and handle UE mobility in association with the connection change from the first AMF to the second AMF, the first base station part of a WAB is further adapted to: obtain (502; 602; 702) one or more configuration parameters needed to establish a connection to the second AMF; establish (504; 604; 704) a connection to the second AMF, based on the one or more configuration parameters; andperform (506; 606; 704) one or more actions related to handling of connectivity of one or more UEs served by the first base station part of the WAB node in relation to movement of the first base station part of the WAB node from the first AMF to the second AMF.

32. A computer program comprising instructions which, when executed on at least one processor, cause the processor to carry out the method according to any of claims 1 to 27.

33. A carrier containing the computer program of claim 32, wherein the carrier is one of an electronic signal, an optical signal, a radio signal, or a computer readable storage medium.

34. A non-transitory computer-readable medium comprising instructions executable by processing circuitry of a first base station part of a Wireless Access and Backhaul, WAB, node, whereby the first base station part of the WAB node is operable to: determine (500; 600; 700) that a connection change from a first Access and Mobility Management Function, AMF, to a second AMF in a same or different Public Land Mobile Network, PLMN, is needed; perform (502-506; 602-606; 702-704) actions that cause a connection change from the first AMF to the second AMF and handle User Equipment, UE, mobility in association with the connection change from the first AMF to the second AMF.

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