WO2023070511A1

WO2023070511A1 - Enhancement on integrated access and backhaul network

Info

Publication number: WO2023070511A1
Application number: PCT/CN2021/127357
Authority: WO
Inventors: Jens Gebert; Ömer BULAKCI; Xiang Xu; Ilkka Antero Keskitalo; Alessio Casati
Original assignee: Nokia Shanghai Bell Co., Ltd.; Nokia Solutions And Networks Oy
Priority date: 2021-10-29
Filing date: 2021-10-29
Publication date: 2023-05-04

Abstract

Example embodiments of the present disclosure relate to devices, methods, apparatuses and computer readable storage media for enhancement on the IAB network. The method comprises: in accordance with a determination that a first terminal device and a first network device roams from a first network to a second network, transmitting a roaming indication to a second network device associated with the second network, the first terminal device and the first network device acting as an IAB node in the first network; causing the roaming of the first network device to be authorized by a third network device of the second network; and communicating in the second network via the first network device, the first network device operating based on parameters associated with the second network. As such, when an IAB node travels across different countries/regions, the service continuity, security, regulatory requirements associated with the IAB node can be guaranteed.

Description

ENHANCEMENT ON INTEGRATED ACCESS AND BACKHAUL NETWORK

FIELD

Embodiments of the present disclosure generally relate to the field of telecommunication and in particular, to devices, methods, apparatus and computer readable storage media for enhancement on integrated access and backhaul (IAB) network.

BACKGROUND

The IAB network is designed to support wireless relaying and backhauling for 5G New Radio (NR) . A relay node in the IAB architecture is called IAB-node, which provides both access and backhaul by using a NR radio access. The network node terminating the wireless backhauling on the network side is called IAB-donor gNB, which is a gNB with added functionalities to support IAB. IAB takes advantage of the split gNB architecture with the central unit (CU) in the IAB-donor and the distributed unit (DU) in the IAB-node, and thus the DU in the IAB-node is also called IAB DU, and the CU in the IAB-donor is also called IAB donor CU. For IAB-node, the F1 interface specified between the gNB CU and gNB DU, is extended over the wireless backhaul connecting IAB DU and the IAB donor CU. The core network interface (e.g., NG interface) terminates at the IAB donor CU. Thus, the IAB node is a radio access network node with a limited visibility to the core network. The IAB network is utilized to support the wireless backhaul.

IAB DU acts as the gNB DU that terminates the NR access interface to UEs. In addition, IAB DU terminates the backhaul link of the next-hop IAB-nodes. IAB-node also supports UE functionality which is referred to as IAB-MT (Mobile Termination) . IAB-MT supports, e.g., physical layer, layer-2, RRC and NAS functionality, and IAB-MT connects with the IAB donor via the serving DU in the IAB-node or the IAB donor. Furthermore, IAB-MT connects to the RRC layer in the IAB donor CU and the NAS layer in the access and mobility management Function (AMF) .

SUMMARY

In general, example embodiments of the present disclosure provide a solution for enhancement on the IAB network.

In a first aspect, there is provided a first terminal device. The first terminal device comprises at least one processor; and at least one memory including computer program codes; the at least one memory and the computer program codes are configured to, with the at least one processor, cause the first terminal device at least to: in accordance with a determination that the first terminal device and a first network device roams from a first network to a second network, transmit a roaming indication to a second network device associated with the second network, the first terminal device and the first network device acting as an integrated access and backhaul, IAB, node in the first network; and cause the roaming of the first network device to be authorized by a third network device of the second network.

In a second aspect, there is provided first network device. The first network device comprises: at least one processor; and at least one memory including computer program codes; the at least one memory and the computer program codes are configured to, with the at least one processor, cause the first network device at least to: in accordance with a determination that a roaming from a first network to a second network is authorized by a third network device of the second network, obtain parameters associated with the second network, the first network device and a first terminal device acting as an integrated access and backhaul, IAB, node in the first network; and enable a communication of a terminal device in the second network based on the parameters associated with the second network, the terminal device being connected to the first network device.

In a third aspect, there is provided a second network device. The second network device comprises: at least one processor; and at least one memory including computer program codes; the at least one memory and the computer program codes are configured to, with the at least one processor, cause the second network device at least to: receive, from a first terminal device, a roaming indication of the first terminal device and a first network device roaming from a first network to a second network, the second network device being associated with the second network, and the first terminal device and the first network device acting as an integrated access and backhaul, IAB, node in the first network; select, based on the roaming indication, a third network device of the second network for determining whether the first network device is authorized to roam in the second network; and in accordance with a determination that the roaming of the first network device is authorized, configure the first network device to be a network device of the second network.

In a fourth aspect, there is provided a third network device. The third network device comprises: at least one processor; and at least one memory including computer program codes; the at least one memory and the computer program codes are configured to, with the at least one processor, cause the third network device at least to: receive, from a second network device of a second network, a first message comprising a roaming indication of a first terminal device and a first network device roaming from a first network to the second network, the third network device being associated with the second network, and the first terminal device and the first network device acting as an integrated access and backhaul, IAB, node in the first network; and in accordance with a determination that the first network device is authorized to roam in the second network, transmit, to the second network device, a second message comprising a roaming authorization indication.

In a fifth aspect, there is provided a method. The method comprises: in accordance with a determination that the first terminal device and a first network device roams from a first network to a second network, transmitting, at a first terminal device, a roaming indication to a second network device associated with the second network, the first terminal device and the first network device acting as an integrated access and backhaul, IAB, node in the first network; and causing the roaming of the first network device to be authorized by a third network device of the second network.

In a sixth aspect, there is provided a method. The method comprises: in accordance with a determination that a roaming from a first network to a second network is authorized by a third network device of the second network, obtaining, at a first network device, parameters associated with the second network, the first network device and a first terminal device acting as an integrated access and backhaul, IAB, node in the first network; and enabling a communication of a terminal device in the second network based on the parameters associated with the second network, the terminal device being connected to the first network device.

In a seventh aspect, there is provided a method. The method comprises: receiving, at a second network device and from a first terminal device, a roaming indication of the first terminal device and a first network device roaming from a first network to a second network, the second network device being associated with the second network, and the first terminal device and the first network device acting as an integrated access and backhaul, IAB, node in the first network; selecting, based on the roaming indication, a third network device of the second network for determining whether the first network device is authorized to roam in the second network; and in accordance with a determination that the roaming of the first network device is authorized, configuring the first network device to be a network device of the second network.

In an eighth aspect, there is provided a method. The method comprises: receiving, at a third network device and from a second network device of a second network, a first message comprising a roaming indication of a first terminal device and a first network device roaming from a first network to the second network, the third network device being associated with the second network, and the first terminal device and the first network device acting as an integrated access and backhaul, IAB, node in the first network; and in accordance with a determination that the first network device is authorized to roam in the second network, transmitting, to the second network device, a second message comprising a roaming authorization indication.

In a nineth aspect, there is provided a first terminal apparatus. The first terminal apparatus comprises: means for in accordance with a determination that the first terminal apparatus and a first network apparatus roams from a first network to a second network, transmitting a roaming indication to a second network apparatus associated with the second network, the first terminal apparatus and the first network apparatus acting as an integrated access and backhaul, IAB, node in the first network; and means for causing the roaming of the first network apparatus to be authorized by a third network apparatus of the second network.

In a tenth aspect, there is provided a first network apparatus. The first network apparatus comprises: means for in accordance with a determination that a roaming from a first network to a second network is authorized by a third network apparatus of the second network, obtaining parameters associated with the second network, the first network apparatus and a first terminal apparatus acting as an integrated access and backhaul, IAB, node in the first network; and means for enabling a communication of a terminal device in the second network based on the parameters associated with the second network, the terminal device being connected to the first network apparatus.

In an eleventh aspect, there is provided a second network apparatus. The second network apparatus comprises: means for receiving, from a first terminal apparatus, an indication of the first terminal apparatus and a first network apparatus roaming from a first network to a second network, the second network apparatus being associated with the second network, and the first terminal apparatus and the first network apparatus acting as an integrated access and backhaul, IAB, node in the first network; means for selecting, based on the roaming indication, a third network apparatus of the second network for determining whether the first network apparatus is authorized to roam in the second network; and means for in accordance with a determination that the roaming of the first network apparatus is authorized, configuring the first network apparatus to be a network device of the second network.

In a twelfth aspect, there is provided a third network apparatus. The third network apparatus comprises: means for receiving, from a second network apparatus of a second network, a first message comprising a roaming indication of a first terminal apparatus and a first network apparatus roaming from a first network to the second network, the third network apparatus being associated with the second network, and the first terminal apparatus and the first network apparatus acting as an integrated access and backhaul, IAB, node in the first network; and means for in accordance with a determination that the first network apparatus is authorized to roam in the second network, transmitting, to the second network apparatus, a second message comprising a roaming authorization indication.

In a thirteenth aspect, there is provided a computer readable medium having a computer program stored thereon which, when executed by at least one processor of a device, causes the device to carry out the method according to the fifth aspect.

In a fourteenth aspect, there is provided a computer readable medium having a computer program stored thereon which, when executed by at least one processor of a device, causes the device to carry out the method according to the sixth aspect.

In a fifteenth aspect, there is provided a computer readable medium having a computer program stored thereon which, when executed by at least one processor of a device, causes the device to carry out the method according to the seventh aspect.

In a sixteenth aspect, there is provided a computer readable medium having a computer program stored thereon which, when executed by at least one processor of a device, causes the device to carry out the method according to the eighth aspect.

In a seventeenth aspect, there is provided an IAB node. The IAB node comprises the first terminal device according to the first aspect and the first network device according to the second aspect.

Other features and advantages of the embodiments of the present disclosure will also be apparent from the following description of specific embodiments when read in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of embodiments of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the disclosure are presented in the sense of examples and their advantages are explained in greater detail below, with reference to the accompanying drawings, where

FIG. 1 illustrates an example roaming scenario in which example embodiments of the present disclosure can be implemented;

FIG. 2 illustrates an example roaming network architecture according to some example embodiments of the present disclosure;

FIG. 3 illustrates a schematic diagram of a roaming process for an IAB node according to some example embodiments of the present disclosure;

FIG. 4 illustrates a signaling chart illustrating a setup process of an IAB-MT according to some example embodiments of the present disclosure;

FIG. 5 illustrates a signaling chart illustrating a setup process of an IAB-DU according to some example embodiments of the present disclosure;

FIG. 6 illustrates a signaling chart illustrating an inter-PLMN handover process according to some example embodiments of the present disclosure;

FIG. 7 illustrates a flowchart of an example method according to some example embodiments of the present disclosure;

FIG. 8 illustrates a flowchart of an example method according to some example embodiments of the present disclosure;

FIG. 9 illustrates a flowchart of an example method according to some example embodiments of the present disclosure;

FIG. 10 illustrates a flowchart of an example method according to some example embodiments of the present disclosure;

FIG. 11 shows a simplified block diagram of a device that is suitable for implementing example embodiments of the present disclosure; and

FIG. 12 shows a block diagram of an example computer readable medium in accordance with some embodiments of the present disclosure.

Throughout the drawings, the same or similar reference numerals represent the same or similar element.

DETAILED DESCRIPTION

Principle of the present disclosure will now be described with reference to some example embodiments. It is to be understood that these embodiments are described only for the purpose of illustration and help those skilled in the art to understand and implement the present disclosure, without suggesting any limitation as to the scope of the disclosure. The disclosure described herein can be implemented in various manners other than the ones described below.

In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skills in the art to which this disclosure belongs.

References in the present disclosure to “one embodiment, ” “an embodiment, ” “an example embodiment, ” and the like indicate that the embodiment described may include a particular feature, structure, or characteristic, but it is not necessary that every embodiment includes the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an example embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

It shall be understood that although the terms “first” and “second” etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish functionalities of various elements. As used herein, the term “and/or” includes any and all combinations of one or more of the listed terms.

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

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

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

(b) combinations of hardware circuits and software, such as (as applicable) :

(i) a combination of analog and/or digital hardware circuit (s) with software/firmware and

(ii) any portions of hardware processor (s) with software (including digital signal processor (s) ) , software, and memory (ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and

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

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

As used herein, the term “communication network” refers to a network following any suitable communication standards, such as fifth generation (5G) systems, Long Term Evolution (LTE) , LTE-Advanced (LTE-A) , Wideband Code Division Multiple Access (WCDMA) , High-Speed Packet Access (HSPA) , Narrow Band Internet of Things (NB-IoT) and so on. Furthermore, the communications between a terminal device and a network device in the communication network may be performed according to any suitable generation communication protocols, including, but not limited to, the first generation (1G) , the second generation (2G) , 2.5G, 2.75G, the third generation (3G) , the fourth generation (4G) , 4.5G, the fifth generation (5G) new radio (NR) communication protocols, a future sixth generation (6G) communication protocols, and/or any other protocols either currently known or to be developed in the future. Embodiments of the present disclosure may be applied in various communication systems. Given the rapid development in communications, there will of course also be future type communication technologies and systems with which the present disclosure may be embodied. It should not be seen as limiting the scope of the present disclosure to only the aforementioned system.

As used herein, the term “network device” refers to a node in a communication network via which a terminal device accesses the network and receives services therefrom. The network device may refer to a base station (BS) or an access point (AP) , for example, a node B (NodeB or NB) , an evolved NodeB (eNodeB or eNB) , a NR Next Generation NodeB (gNB) , a Remote Radio Unit (RRU) , a radio header (RH) , a remote radio head (RRH) , Integrated Access and Backhaul (IAB) node, a relay, a low power node such as a femto, a pico, and so forth, depending on the applied terminology and technology. The network device is allowed to be defined as part of a gNB such as for example in CU/DU split in which case the network device is defined to be either a gNB-CU or a gNB-DU.

The term “terminal device” refers to any end device that may be capable of wireless communication. By way of example rather than limitation, a terminal device may also be referred to as a communication device, user equipment (UE) , a Subscriber Station (SS) , devices such as digital cameras, gaming terminal devices, music storage and playback appliances, vehicle-mounted wireless terminal devices, wireless endpoints, mobile stations, laptop-embedded equipment (LEE) , laptop-mounted equipment (LME) , USB dongles, smart devices, wireless customer-premises equipment (CPE) , an Internet of Things (IoT) device, a watch or other wearable, a head-mounted display (HMD) , a vehicle, a drone, a medical device and applications (e.g., remote surgery) , an industrial device and applications (e.g., a robot and/or other wireless devices operating in an industrial and/or an automated processing chain contexts) , a consumer electronics device, a device operating on commercial and/or industrial wireless networks, and the like. The terminal device may also correspond to Mobile Termination (MT) part of the integrated access and backhaul (IAB) node (a.k.a. a relay node) . In the following description, a Portable Subscriber Station, a Mobile Station (MS) , or an Access Terminal (AT) . The terminal device may include, but not limited to, a mobile phone, a cellular phone, a smart phone, voice over IP (VoIP) phones, wireless local loop phones, a tablet, a wearable terminal device, a personal digital assistant (PDA) , portable computers, desktop computer, image capture terminal, and so on. The terms “terminal device” , “communication device” , “terminal” , “user equipment” and “UE” may be used interchangeably.

Although functionalities described herein can be performed, in various example embodiments, in a fixed and/or a wireless network node, in other example embodiments, functionalities may be implemented in a user equipment apparatus (such as a cell phone or tablet computer or laptop computer or desktop computer or mobile IoT device or fixed IoT device) . This user equipment apparatus can, for example, be furnished with corresponding capabilities as described in connection with the fixed and/or the wireless network node (s) , as appropriate. The user equipment apparatus may be the user equipment and/or or a control device, such as a chipset or processor, configured to control the user equipment when installed therein. Examples of such functionalities include the bootstrapping server function and/or the home subscriber server, which may be implemented in the user equipment apparatus by providing the user equipment apparatus with software configured to cause the user equipment apparatus to perform from the point of view of these functions/nodes.

The IAB technology enables a flexible and dense deployment of NR cells without densifying the transport network proportionately. A diverse range of deployment scenarios can be envisioned including support for outdoor small cell deployments, indoors (e.g., shopping centers) , or even mobile relays (e.g., in a car, bus, train, or unmanned aerial vehicle, UAV, such as a drone) . A typical use case of mobile relay may be the vehicle mounted relay (VMR) , which includes potential new requirements for 5G system (5GS) support of mobile base station relays mounted on vehicles, using 5G NR over radio links toward UEs and a macro RAN that is connected to 5G core (5GC) . A vehicle can be any entity that may host/carry the access node, e.g., relay, functionality. For example, a vehicle can be a car, bus, train, or unmanned aerial vehicle, UAV, such as a drone. This covers aspects related to:

● vehicle base station relays providing services to the UEs inside the vehicle or in the vicinity of the vehicle;

● the end-to-end service continuity during mobility scenarios including mobility of the relays; and

● aspects related to roaming of relays, security, regulatory requirements (e.g., for emergency services) , charging, spectrum interference.

An IAB node may serve as a vehicle mounted relay in the mobility scenario, and roaming of the IAB node may occur, for example, when the bus/car/train equipped with the IAB node moves from one country/region to another country/region. In a case where the IAB node roams from a home Public Land Mobile Network (HPLMN) to a visited PLMN (VPLMN) , or from one VPLMN to another VPLMN, it may be first configured by a first operator of the HPLMN and then reconfigured by a second operator of the VPLMN. Accordingly, the IAB node should be reconfigured to be compatible with existing deployments and regulations in the visited country/region, for example, without interfering with the second operator’s network, properly using radio resources of the VPLMN and so on. Thus, an enhanced roaming procedure for the IAB node is required.

Principle and embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. FIG 1 illustrates an example roaming scenario in which example embodiments of the present disclosure can be implemented.

The roaming scenario roaming may be based on a 5GS architecture 100, and an IAB node 110 including IAB-DU 106 and IAB-MT 105 may be deployed inside a vehicle 107 that moves from a coverage of a first network 101 (e.g., the HPLMN) to a coverage of a second network 102 (e.g., the VPLMN) . The terminal device 108 (e.g., UE) inside the vehicle 107 may be served by the IAB node 110. As shown in FIG. 1, there may be a plurality of

base stations

103 and 104 which provides the coverage of the first network 101. In addition, there may be at least one network device 120 that provides the coverage of the second network 102, and a core network (CN) device 130 in the second network 102. The CN device 130 is connected to the Internet 140.

FIG. 2 illustrates an example roaming network architecture 200 according to some example embodiments of the present disclosure. As shown in FIG. 2, the IAB node 110 may consist of an IAB mobile terminal (IAB-MT) 105 and an IAB distributed unit (IAB-DU) 106, which are separately configured in the roaming procedure. The network device 120 may be referred to a IAB donor, which is located at the RAN side. The IAB donor consists of an IAB donor-DU and an IAB donor-CU. The functionalities of IAB donor-CU may be further divided into an IAB donor-CU control plane (IAB donor-CU-CP) and an IAB donor-CU user plane (IAB donor-CU-UP) . The CN device 130 may include one or more of AMF, SMF, UPF and so on.

The first network 101 and the second network 102 may be operated by different operators (e.g., a first operator and a second operator) , and an IAB roaming agreement may be reached between the first and second operators. In particular, upon roaming in the second network 102, the IAB node 110 may be reconfigured in such a way that the IAB-DU 106, as a part of the IAB node 110, acts as a base station of the VPLMN. That is, the roaming IAB-DU 106 should operate based on parameters associated with the second network 102, such as, a maximum transmission power, a maximum bandwidth, antenna configurations, slicing support, and so on.

In the following descriptions, two possible procedures for roaming between the first network 101 and the second network 102 need to be considered, that is, the IAB node 110 switches on in the second network 102, and the IAB node 110 performs inter-PLMN handover between the first network 101 and the second network 102.

It is to be understood that the numbers of IAB nodes, and network devices in both the RAN and CN shown in FIG. 1 are given for the purpose of illustration without suggesting any limitations. The network system 100 may include any suitable number of IAB nodes, network devices and additional devices adapted for implementations of the present disclosure.

Depending on the communication technologies, the network system 100 may be a Code Division Multiple Access (CDMA) network, a Time Division Multiple Address (TDMA) network, a Frequency Division Multiple Access (FDMA) network, an Orthogonal Frequency-Division Multiple Access (OFDMA) network, a Single Carrier-Frequency Division Multiple Access (SC-FDMA) network or any others. Communications discussed in the network 100 may conform to any suitable standards including, but not limited to, New Radio Access (NR) , Long Term Evolution (LTE) , LTE-Evolution, LTE-Advanced (LTE-A) , Wideband Code Division Multiple Access (WCDMA) , Code Division Multiple Access (CDMA) , cdma2000, and Global System for Mobile Communications (GSM) and the like. Furthermore, the communications may be performed according to any generation communication protocols either currently known or to be developed in the future. Examples of the communication protocols include, but not limited to, the first generation (1G) , the second generation (2G) , 2.5G, 2.75G, the third generation (3G) , the fourth generation (4G) , 4.5G, the fifth generation (5G) communication protocols, or any communication protocols to be developed in the future. The techniques described herein may be used for the wireless networks and radio technologies mentioned above as well as other wireless networks and radio technologies. For clarity, certain aspects of the techniques are described below for NR, and NR terminology is used in much of the description below.

As previously described, the IAB-MT part and the IAB-DU part of the roaming IAB node are separately reconfigured in the new PLMN. In the following, the setup and reconfigurations for the roaming process will be discussed in connection with FIGs. 3 to 6. FIG. 3 illustrates a schematic diagram of a roaming process 300 of the IAB node which switches on in the new PLMN according to some example embodiments of the present disclosure. The process 300 may involve the IAB node 110, the IAB donor 120, the CN device 130 as shown in FIG. 1. For the purpose of discussion, the process 300 will be described with reference to FIG. 1.

As shown in FIG. 3, the process 300 may include a phase 1 of IAB-MT 105 setup, a phase 2-1 of backhaul radio link control (RLC) channel establishment for IAB-MT 105, a phase 2-2 of routing update for the IAB-DU 106, and a phase 3 of IAB-DU 106 setup.

Turning to FIG. 4, which illustrates a signaling chart illustrating a setup process of the IAB-MT in the scenario shown in FIG. 3. The process 400 may involve the IAB-MT 105, the serving DU 421 which may be a DU in an IAB node (in multi-hop case) or an IAB-donor DU included in, the IAB-donor 120, the IAB donor CU 421 which includes the IAB-donor CU-CP and the IAB-donor CU-UP (not shown) , and the CN device 130 which may include the AMF, SMF, UPF and so on.

As shown in FIG. 4, upon switching on in the coverage of the second network 102, the IAB-MT 105 performs a 405 RRC setup procedure with the serving DU 421. The RRC setup procedure may include, for example,

1) the IAB-MT 105 in RRC_IDLE mode transmitting a RRCSetupRequest with an identity of the IAB node 110 to the serving DU 421;

2) if the IAB-MT 105 is allowed to access the second network 102, the serving DU 421 transmitting the F1AP initial UL RRC message transfer including C-RNTI to the IAB-donor CU-CP of the IAB-donor CU 422;

3) the IAB-donor CU-CP of the IAB-donor CU 422 allocating a gNB-CU UE F1AP identity for the IAB-MT 105, and transmitting the F1AP DL RRC message transfer including RRCSetup and the gNB-CU UE F1AP identity to the serving DU 421; and

4) the serving DU 421 transmitting the RRCSetup message to the IAB-MT 105.

5) the IAB-MT reply with a RRCSetupComplete to the serving DU 421, which is further forwarded to the IAB-donor CU-CP of the IAB-donor CU 422. As a result, a RRC connection is established between the IAB-MT 105 and the IAB-donor 120, and the IAB-MT operates in RRC_CONNECTED mode.

The IAB-MT 105 transmits 410 a roaming indication to the serving DU 421. For example, the roaming indication may be the IAB node indication and transmitted in a RRC message, such as, the RRCSetupComplete message. Such an indication may cause the serving DU 421 to select an AMF supporting IAB. The roaming restrictions and access restrictions for the IAB-MT 105 may be provided in the UE context from the CN device 130 to the IAB donor 120 at registration/connection establishment or TA update.

The serving DU 421 transmits 415 the IAB node indication to the IAB-donor CU-CP of the IAB-donor CU 422. For example, the IAB-donor DU 421 may encapsulate the RRC connection setup complete message and the IAB node indication in a F1AP UL RRC message transfer to the IAB-donor CU-CP of the IAB-donor CU 422.

The IAB-donor CU-CP of the IAB-donor CU 422 transmits 420 the IAB node indication to the CN device 130, for example, the AMF. For example, the IAB-donor CU-CP of the IAB-donor CU 422 may generate an initial UE message including the IAB node indication, registration request, RAN UE NGAP ID and so on.

If needed, the CN device 130 performs 425 the PDU session establishment and update for the IAB node 110. To this end, several signaling may be exchanged among the AMF, SMF and UPF including PDU Session UpdateSMContext Request and Response, Session Modification Request and Response, etc., which are not described in details, since the present disclosure is not limited in this regard.

The CN device 130 transmits 430 an IAB node allowed indication indicating whether the IAB node 110 is authorized to roam in the second network 102 to the IAB-donor CU-CP of the IAB-donor CU 422. In some example embodiments, the IAB node allowed indication may be added to the roaming restrictions and access restrictions, and transmitted by the CN device 13 (for example, AMF) . Alternatively, in some other embodiments, the IAB node allowed indication may be transmitted as independent information transmitted from the UDM to the AMF, and the AMF transmits this information with an indication of the PLMN identity of the first network 101 to the IAB-donor 120.

In particular, if the IAB node allowed indication is set to true, it indicates that the IAB node 110 is allowed to roam in the VPLMN. Upon receipt of the IAB node allowed indication, a bearer context is setup 435 between the IAB-donor CU-CP and the IAB-donor CU-UP of the IAB-donor CU 422, which may be, for example, based on the E1AP protocol.

Otherwise, if the IAB node allowed indication is set to false, the process 400 for IAB node 110 ends.

Turning to FIG. 5, which illustrates a signaling chart illustrating a setup process of the IAB-DU in the scenario shown in FIG. 3. The process 500 may involve the IAB-DU 106, the IAB donor 120 including the IAB-donor DU 521 and the IAB-donor CU 522, and the CN device 130 which may include the AMF, SMF, UPF and so on.

Typically, an initial configuration of the IAB-DU 106 is configured by an operation, administration, and maintenance (OAM) node (not shown) of the first network 101. However, the settings of the initial configuration may be unsuitable for the second network 102, for example, in terms of spectrum, bandwidth, transmission power and so on. Accordingly, the IAB-DU 106 needs to be reconfigured with suitable parameters and to act as a base station of the second network 102.

As shown in FIG. 5, the IAB-DU 106 connects with the IAB-donor CU 522 via the IAB-donor DU 521. It is to be understood that the IAB-DU 106 may also connect with the IAB-donor CU 522 via the IAB-donor DU 521, and one or more intermediate IABs (not shown in the figure) . The IAB-DU 106 sets up 505 the transport network connection with the IAB-donor CU 522.

In some example embodiments, the reconfiguration of the IAB-DU 106 may be performed via a F1 procedure. In particular, the IAB-DU 106 transmits 510 a F1AP message (for example, a F1AP setup request message) to the IAB-donor CU 522. The F1AP message (for example, a F1AP setup request message) may include, for example, a network identity of the first network 101, a name of the IAB-DU 106, a list of served cells of the IAB-DU 106, system information of the IAB-DU 106, and so on.

In some example embodiments, an agreement on the configuration for VPLMN may be negotiated between the HPLMN (i.e., the first network 101) and a set of VPLMNs, and in this case, the HPLMN may preconfigure the IAB-DU 106 with profiles of relevant VPLMNs where the IAB-DU 106 is allowed to operate.

In some example embodiments, the first network 106 may provide a pre-configuration for a given VPLMN or pre-configurations for each of the allowed PLMNs to the IAB-DU 106. This pre-configuration may be modified by respective VPLMNs. If the IAB node 110 is authorized to roam in a specific VPLMN, a name or an IP address for the OAM server and authentication information needed to get authorization for OAM transactions in the VPLMN may be provided to the IAB-MT 105 in a message (for example, the registration accept message) . This allows the IAB node 110 to be configured with the necessary CU address.

Upon receipt of the F1AP message (for example, a F1AP setup request message) , the IAB-donor CU 522 initiates 515 a setup/configuration update procedure with the CN device 130.

In some example embodiments, the second network 102 may activate certain CU features and donor DU features based on the received network identity of the first network 101 (e.g., HPLMN ID) , and potentially any additional configuration profile for a specific type of IAB-DU 106 which is, for example, in the vehicle mounted Relay (VMR) . This configuration profile may be associated with a type ID of the IAB Node 110 provided in the registration message.

The IAB-donor CU 522 may transmit 520 a message to the IAB-DU 106, such as, a F1AP F1 Setup Response message, or a F1AP gNB-CU configuration update message, or any other F1AP message. The message may include the parameters to be configured in the IAB-DU 106, in order for the IAB-DU 106 to work in the second network 102. The message may also include a list of cells to be activated, for example, the cells not activated in previous F1 Setup Response message.

The IAB-DU 106 may transmit an update acknowledge message to the IAB-donor CU 522, such as, a gNB-CU configuration update acknowledge message. The configuration update acknowledge message may include, for example, a list of cells that is not activated. The IAB-DU 106 may use the configured parameters, and start 525 the operation in the second network 102.

In some example embodiments, an Xn/X2 setup procedure may be executed between the IAB-donor CU 522 and neighboring gNB-CUs (not shown in the figure) . The Xn/X2 setup procedure may follow a currently known implementation or any implementation to be developed in the future. The present disclosure is not limited in this regard.

Alternatively, in a case where the OAM of the second network 102 is compatible with the IAB-DU 106, the reconfiguration of the IAB-DU 106 may be performed via the OAM.

According to the example embodiments of the present disclosure, there is provided a roaming mechanism for the IAB node. The roaming mechanism can support for reconfigurations of a roaming IAB node that switch on in coverage of a new PLMN. The IAB node is reconfigured with the parameters suitable for the new VPLMN, and thus can operate as a base station of the VPLMN. In addition, the reconfiguration can be implemented via the E1 and F1 procedures, and thus the roaming mechanism would not increase the signaling overhead.

FIG. 6 illustrates a signaling chart illustrating an inter-PLMN handover process 600 according to some example embodiments of the present disclosure. The process 600 may involve the IAB node 110 consisting of the IAB-MT 105 and the IAB-DU 106, the IAB donor 120 and the CN device 130 as shown in FIG. 1. For the purpose of discussion, the process 600 will be described with reference to FIG. 1.

The IAB node 110 may move from the coverage of the first network 101 to the coverage of the second network 102, which initiates the inter-PLMN handover procedure 600. In the inter-PLMN handover scenario, the first network 101 may be the HPLMN of the IAB node 110 or a first VPLMN, and the second network 102 may be a second VPLMN different from the first VPLMN.

A RAN handover procedure 605 is performed, and the IAB-MT 105 connects with the IAB donor 120. For example, an Inter NG-RAN node N2 based handover may be executed to support the switching between different operators. During the handover of the IAB-MT 105 or upon the handover of the IAB-MT 105 is completed, the IAB-DU 106 stops 610 operations in the first network 101. The IAB-DU 106 then performs 615 a roaming authorization procedure similar to the steps discussed in connection with FIG. 5. Once the roaming is authorized by the second network 102, the IAB donor 120 configures 620 the IAB-DU 106 to be a base station of the second network 102. For example, the IAB donor 120 may configure the IAB-DU 106 with parameters, such as, the spectrum, bandwidth, quality of service (QoS) , transmission power, slice support information, a Synchronization Signal and PBCH block (SSB) configuration, a physical cell identity (PCI) , etc. to be used in the second network 102. The IAB-DU 106 operates 625 based on the parameters associated with the second network 102.

According to the example embodiments of the present disclosure, there is provided a roaming mechanism for IAB node. The roaming mechanism can support either a roaming IAB node that switch on in coverage of a new PLMN operating by a different operator from the HPLMN’s operator, or a roaming IAB moving from one PLMN to another one.

In addition, the roaming mechanism takes differences in terms of QoS, traffic parameters, charging policy, slice configurations of the HPLMN and the VPLMN, and/or a current VPLMN and a VPLMN allowed for roaming into account. In the enhanced mechanism, it is able to reconfigure the IAB-DU to be a base station of the VPLMN where the IAB node is moving to. As such, when the IAB node travels across different countries or regions, the service continuity, compatibility, performance, security, regulatory requirements associated with the IAB node can be guaranteed.

FIG. 7 illustrates a flowchart of an example method 700 according to some example embodiments of the present disclosure. The method 700 can be implemented at a first terminal device, which may be an IAB node including an IAB-MT, for example, the IAB-MT 105 described with reference to FIGs. 1, 2, 4 and 6. For the purpose of discussion, the method 700 will be described with reference to FIG. 1.

At 710, the first terminal device 105 determines that the first terminal device 105 and a first network device 106 roams from a first network 101 to a second network 102. The first terminal device 105 and the first network device 106 acts as an IAB node 110 in the first network 101.

The first network 101 and the second network 102 are operated by different operators and even deployed in different countries or regions. The second network device 120 may be the IAB donor of the second network 102, which includes a serving DU (e.g. an IAB-DU, or an IAB-doner DU) , an IAB-donor CU. The IAB-donor CU may include an IAB-donor CU-CP and an IAB-donor CU-UP. The third network device 130 may be a core network device of the second network 102, for example, one or more of the AMF, SMF, UPF and so on.

In some other example embodiments, the IAB node 110 including the first terminal device 105 and the first network device 106 may move from the first network 101 to the second network 102, and the first terminal device 105 may determine the inter-PLMN handover to be performed. In this case, the first network 101 may be either the HPLMN or a first VPLMN, and the second network 102 may be a second VPLMN.

In some example embodiments, the first terminal device 105 may determine the roaming from the HPLMN to the VPLMN upon switching on in the coverage of the second network 102.

In some other example embodiments, the first terminal device 105 may determine the roaming from the HPLMN to the VPLMN upon moving from coverage of the first network 101 to coverage of the second network 102.

Upon determining the roaming of the IAB node 110, the first terminal device 105, at 720, transmits a roaming indication to a second network device 120 associated with the second network 102.

In some example embodiments, the transmission of the roaming indication may cause the second network device 120 to select the third network device 130 for determining whether the first network device 106 is authorized to roam in the second network 102. The roaming indication may be the IAB Node Indication and transmitted in a RRC message, for example, the RRC setup complete message.

In some example embodiments, the roaming indication may be an IAB node indication and is transmitted in a RRC message.

In the embodiments where the IAB node 110 moves from the coverage of the first network 101 to the second network 102, before transmitting the roaming indication, the first terminal device 105 may perform a N2 based handover procedure with the second network device 120.

At 730, the first terminal device 105 causes the roaming of the first network device 106 to be authorized by the third network device 130 of the second network 102. In some example embodiments,

The first network device 106 may then communicate in the second network 102 via the first terminal device 105. The first network device 106 may operate based on parameters associated with the second network 102. In some example embodiments, the first network device 106 may be configured by the second network device 120 and the third network device 130 to operate as a network device of the second network 102.

In some example embodiments, the parameters associated with the second network 102 may be preconfigured at the second network device 120, and provided to the first network device 106 upon the roaming is authorized.

In some example embodiments, the first terminal device 105 may receive, from the second network 102, a message (for example, registration accept message) comprising a name or IP address for the OAM node and authentication information for OAM transaction in the second network 102.

In some example embodiments, the third network device 130 may comprise a core network device of the second network 102, and the parameters may be determined by the core network or the OAM node of the second network 102.

In some example embodiments, the parameters may be determined based on a type of the first network device 106 or a type of the IAB node 110.

In some example embodiments, the parameters associated with the second network 102 may comprise at least one of a spectrum, a bandwidth, a transmission power, quality of service, traffic parameters, a slice configuration, a SSB configuration or a PCI to be used by the first network device 106 in the second network 102.

In some example embodiments, the first terminal device may be the IAB-MT, the first network device may be the IAB-DU, the second network device may be the IAB donor, and the third network device may be the core network device of the second network 102.

FIG. 8 illustrates a flowchart of an example method 800 according to some example embodiments of the present disclosure. The method 800 can be implemented at a first network device, which may be an IAB node including an IAB-DU, for example, the IAB-DU 106 described with reference to FIGs. 1, 2, 5 and 6. For the purpose of discussion, the method 800 will be described with reference to FIG. 1.

At 810, the first network device 106 determines that a first terminal device 105 and the first network device 106 is roaming from a first network 101 to a second network 102 is authorized by a third network device 130 of the second network 102. The first network device 106 and the first terminal device 105 may act as the IAB node 110 in the first network 101.

In some example embodiments, the first network 101 may be a HPLMN of the IAB node 110, and the second network 102 may be the VPLMN of the IAB node 110.

In some example embodiments, the first network 101 may be a first VPLMN, and the second network 102 may be a different second VPLMN.

At 820, the first network device 106 obtains parameters associated with the second network 102. The parameters may be obtained via a F1 procedure with the second network device 120 of the second network 102. The second network device 120 may be an IAB donor, or a gNB, or a gNB-DU of the second network 102.

In some example embodiments, to obtain the parameters, the first network device 110 may transmit, to the second network device 120, a F1 setup request comprising parameters associated with the first network 101. In addition, the first network device 110 may receive, from the second network device 120, a F1 setup response comprising the parameters associated with the second network 102.

In some example embodiments, the parameters may be included in configuration profiles preconfigured by the first network 101. The first network device 110 may determine whether the roaming is authorized. If the roaming is authorized, the first network device 106 may activate the parameters associated with the second network 102. In this example, the parameters may be preconfigured at the first network device 106.

In some example embodiments, the third network device 130 may be a core network device of the second network 102, and the parameters may be determined by the core network device based on a type of the first network device 106 or a type of IAB node 110.

In some example embodiments, the parameters may be obtained from the OAM, node of the second network 102.

In some example embodiments, the first network device 106 may stop operating in the first network 101 upon moving from the coverage of the first network 101 to the coverage of the second network 102.

At 830, the first network device 106 enables a communication of a terminal device 108 in the second network 102 based on the parameters associated with the second network 102. The terminal device 108 is connected to the second network 102 via the first network device 106.

In some example embodiments, the first terminal device 105 may be an IAB-MT, the first network device 106 may be an IAB-DU, the connected terminal device may be a UE 107, and the third network device 130 may be a core network device of the second network 102.

FIG. 9 illustrates a flowchart of an example method 900 according to some example embodiments of the present disclosure. The method 900 can be implemented at a second network device, which may be an IAB-donor as shown in FIGs. 1 to 6. The IAB-donor may include an IAB-donor DU and the IAB-donor CU, which may further include the IAB-donor CU-CP and the IAB-donor CU-UP. For the purpose of discussion, the method 900 will be described with reference to FIG. 1.

At 910, the second network device 120 receives, from a first terminal device 105, a roaming indication of the first terminal device 105 and a first network device 106 roaming from a first network 101 to a second network 102. The second network device 120 is associated with the second network 102, and the first terminal device 105 and the first network device 106 may act as the IAB node 110 in the first network 101.

In some example embodiments, the roaming indication may be the IAB node indication and transmitted in a RRC message.

At 920, the second network device 120 selects, based on the roaming indication, a third network device 130 of the second network 102 for determining whether the first network device 106 is authorized to roam in the second network 102.

At 930, the second network device 120 determines whether the roaming of the first network device 106 is authorized.

In some example embodiments, the second network device 120 may transmit a first message comprising the roaming indication to the third network device 130. The second network device 120 may receive, from the third network device 130, a second message comprising a roaming authorization indication. The second network device 120 may then determine whether the first network device 106 is authorized based on the roaming authorization indication.

If the roaming is authorized, at 940, the second network device 120 may configure the first network device 106 to be a network device of the second network 102. The configuring of the first network device 106 may be performed via a F1AP procedure.

In some example embodiments, to configure the first network device 106, the second network device 120 may receive, from the first network device 106, a F1AP setup request comprising parameters associated with the first network 101. The second network device 120 may then transmit, to the first network device 106, a F1AP setup response comprising the parameters associated with the second network 102.

In some example embodiments, the first message may be a NGAP INITIAL UE MESSAGE, which may include a registration request from the IAB node 110, and the second message may be a NGAP message including roaming restrictions and access restrictions.

In some example embodiments, the parameters associated with the second network 102 are preconfigured at the first network device 106.

In some example embodiments, the second network device 120 may transmit parameters associated with the second network 102 to the first network device 106. The roaming authorization indication may include an identification of the first network 101. The second network device 120 may be configured with the parameters to be transmitted to the first network device 106. Based on the roaming authorization indication, the second network device 120 may determine the parameters to be transmitted to the first network device 106. For example, the second network device 120 may be configured with one set of parameters to be transmitted to a network device from one network, and another set of parameters to be transmitted to a network device from another network. Based on the identification of the network (e.g., the identification of the first network 101) , the second network device 120 may determine a specific set of parameters to be transmitted to the network device (e.g., first network device 106) . The parameters transmitted to the first network device 106 are associated with the second network 102, or to be used by the first network device 102 in the second network 102. The first network device 106 may then operate as a base station of the second network 102 based on the parameters.

In some example embodiments, the second network device 120 may transmit, to the first terminal device 105, a message (for example, registration accept message) comprising a name or an IP address for OAM node and authentication information for OAM transaction in the second network 102. In this example, the parameters associated with the second network 102 are determined by the OAM node.

In some example embodiments, the parameters associated with the second network 102 are preconfigured at the second network device 120, and the parameters are determined based on a type of the first network device 106 or a type of the IAB node 110.

In some example embodiments, the second network device 120 may perform a N2 based handover procedure for the first terminal device 105.

In some example embodiments, the first terminal device 105 may be an IAB-MT, the first network device 106 may be an IAB-DU, the second network device may be the IAB-donor of the second network 102, and the third network device 130 may be a core network device of the second network 102.

FIG. 10 illustrates a flowchart of an example method 1000 according to some example embodiments of the present disclosure. The method 1000 can be implemented at a third network device, which may be a CN device as shown in FIGs. 1 to 6. The CN device may include one or more of AMF, SMF, UPF and so on. For the purpose of discussion, the method 1000 will be described with reference to FIG. 1.

At 1010, the third network device 130 receives, from a second network device 120 of a second network 102, a first message comprising a roaming indication of a first terminal device 105 and a first network device 106 roaming from a first network 101 to the second network 102. The first terminal device 105 and the first network device 106 may act as the IAB node 110 in the first network 101.

In some example embodiments, the first message may include a registration request from the IAB node 110, and the second message may be roaming restrictions and access restrictions.

At 1020, the third network device 130 determines whether to authorize the roaming IAB node 110.

If the IAB node 110 is authorized to roam in the second network 102, at 1030, the third network device 130 transmits, to the second network device 120, a second message comprising a roaming authorization indication.

In some example embodiments, the transmission of the roaming authorization indication may cause the second network device 120 to configure the first network device 106 to be a network device of the second network 102.

In some example embodiments, the roaming authorization indication may include an identification of the first network, parameters corresponding to identification of the first network 101 is preconfigured at the second network device 102. In this example, the transmission of the roaming authorization indication may cause the second network device 120 to determine the parameters (for example, based on the identification of the first network) , and configure the first network device 106 with the parameters to be used in the second network 102.

In some example embodiments, the third network device 130 may perform a N2 based handover procedure for the first terminal device 105.

In some example embodiments, a first terminal apparatus capable of performing the method 700 (for example, the IAB-MT 105) may comprise means for performing the respective steps of the method 700. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module. In some embodiments, the means may comprise at least one processor and at least one memory including computer program code. The at least one memory and computer program code are configured to, with the at least one processor, cause performance of the first terminal apparatus.

In some example embodiments, the first terminal apparatus comprises: means for in accordance with a determination that the first terminal apparatus and a first network apparatus roams from a first network to a second network, transmitting, at a first terminal apparatus, a roaming indication to a second network apparatus associated with the second network, the first terminal apparatus and the first network apparatus acting as an integrated access and backhaul, IAB, node in the first network; causing the roaming of the first network apparatus to be authorized by a third network apparatus of the second network; and communicating in the second network via the first network apparatus, the first network apparatus operating based on parameters associated with the second network.

In some example embodiments, the parameters associated with the second network are preconfigured at the first network apparatus, and the parameters are activated upon the roaming of the first network apparatus is authorized.

In some example embodiments, the parameters associated with the second network are preconfigured at the second network apparatus, and provided to the first network apparatus upon the roaming is authorized.

In some example embodiments, the first terminal apparatus further comprises: means for receiving, from the second network, a message comprising a name or an address for an operation administrator and maintenance, OAM, node and authentication information for OAM transaction in the second network.

In some example embodiments, the third network apparatus comprises a core network apparatus of the second network, and the parameters are determined by the core network or an operation administrator and maintenance, OAM, node of the second network.

In some example embodiments, a first network apparatus capable of performing the method 800 (for example, the IAB-DU 106) may comprise means for performing the respective steps of the method 800. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module. In some embodiments, the means may comprise at least one processor and at least one memory including computer program code. The at least one memory and computer program code are configured to, with the at least one processor, cause performance of the first network apparatus.

In some example embodiments, the first network apparatus comprises: means for in accordance with a determination that a roaming from a first network to a second network is authorized by a third network apparatus of the second network, obtaining, at a first network apparatus, parameters associated with the second network, the first network apparatus and a first terminal apparatus acting as an integrated access and backhaul, IAB, node in the first network; and means for enabling a communication of a terminal device in the second network based on the parameters associated with the second network, the terminal device is connected to the first network apparatus.

In some example embodiments, the parameters are obtained via a F1 procedure with a second network apparatus of the second network, and the second network apparatus comprises an integrated access and backhaul, IAB, donor of the second network.

In some example embodiments, the means for obtaining the parameters comprises: means for transmitting, to the second network apparatus, a F1 setup request comprising parameters associated with the first network; and means for receiving, from the second network apparatus, a F1 setup response comprising the parameters associated with the second network.

In some example embodiments, the means for obtaining the parameters comprises: means for in accordance with a determination that the roaming is authorized, activating the parameters associated with the second network, the parameters being preconfigured at the first network apparatus.

In some example embodiments, the third network apparatus comprises a core network apparatus of the second network and the parameters are determined by the core network apparatus based on a type of the first network apparatus.

In some example embodiments, the parameters are obtained from an operation administrator and maintenance, OAM, node of the second network.

In some example embodiments, a second network apparatus capable of performing the method 900 (for example, the IAB-donor 120) may comprise means for performing the respective steps of the method 900. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module. In some embodiments, the means may comprise at least one processor and at least one memory including computer program code. The at least one memory and computer program code are configured to, with the at least one processor, cause performance of the second network apparatus.

In some example embodiments, the second network apparatus comprises: means for receiving, at a second network apparatus and from a first terminal apparatus, an indication of the first terminal apparatus and a first network apparatus roaming from a first network to a second network, the second network apparatus being associated with the second network, and the first terminal apparatus and the first network apparatus acting as an integrated access and backhaul, IAB, node in the first network; means for selecting, based on the indication, a third network apparatus of the second network for determining whether the first network apparatus is authorized to roam in the second network; and means for in accordance with a determination that the roaming of the first network apparatus is authorized, configuring the first network apparatus to be a network device of the second network.

In some example embodiments, the second network apparatus further comprises: means for transmitting a first message comprising the roaming indication to the third network apparatus; means for receiving, from the third network apparatus, a second message comprising a roaming authorization indication; and means for determining whether the first network apparatus is authorized based on the roaming authorization indication.

In some example embodiments, the first message comprises a registration message, and the second message comprises roaming restrictions and access restrictions.

In some example embodiments, the roaming authorization indication comprises an identification of the first network.

In some example embodiments, the second network apparatus further comprises: means for determining parameters based on the identification of the first network; and means for transmitting parameters to be used in the second network to the first network apparatus.

In some example embodiments, the second network apparatus further comprises: means for transmitting, to the first terminal network, a message comprising a name or an IP address for an operation administrator and maintenance, OAM, node and authentication information for OAM transaction in the second network, and the parameters are determined by the OAM node.

In some example embodiments, wherein the parameters associated with the second network are preconfigured at the second network apparatus, and the parameters are determined based on a type of the first network apparatus.

In some example embodiments, a third network apparatus capable of performing the method 1000 (for example, the CN device 130) may comprise means for performing the respective steps of the method 1000. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module. In some embodiments, the means may comprise at least one processor and at least one memory including computer program code. The at least one memory and computer program code are configured to, with the at least one processor, cause performance of the third network apparatus.

In some example embodiments, the third network apparatus comprises: means for receiving, at a third network apparatus and from a second network apparatus of a second network, a first message comprising an indication of a first terminal apparatus and a first network apparatus roaming from a first network to the second network, the third network device being associated with the second network, and the first terminal apparatus and the first network apparatus acting as an integrated access and backhaul, IAB, node in the first network; and means for in accordance with a determination that the first network apparatus is authorized to roam in the second network, transmitting, to the second network apparatus, a second message comprising a roaming authorization indication.

In some example embodiments, the transmission of the roaming authorization indication causes the second network apparatus to configure the first network apparatus to be a network device of the second network.

In some example embodiments, the roaming authorization indication comprises an identification of the first network, parameters corresponding to identification of the first network is preconfigured at the second network apparatus, and the transmission of the roaming authorization indication causes the second network apparatus to configure the first network apparatus with the parameters associated with the second network.

FIG. 11 is a simplified block diagram of a device 1100 that is suitable for implementing embodiments of the present disclosure. The device 1100 may be provided to implement the communication device, for example the IAB-MT 105, the IAB-DU 106, the IAB-node 110, the IAB donor 120, the IAB donor-DU, the IAB donor CU, and the AMF 130 as shown in FIGs. 1 to 6. As shown, the device 1100 includes one or more processors 1110, one or more memories 1140 coupled to the processor 1110, and one or more transmitters and/or receivers (TX/RX) 1140 coupled to the processor 1110.

The TX/RX 1140 is for bidirectional communications. The TX/RX 1140 has at least one antenna to facilitate communication. The communication interface may represent any interface that is necessary for communication with other network elements.

The processor 1110 may be of any type suitable to the local technical network and may include one or more of the following: general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples. The device 1100 may have multiple processors, such as an application specific integrated circuit chip that is slaved in time to a clock which synchronizes the main processor.

The memory 1120 may include one or more non-volatile memories and one or more volatile memories. Examples of the non-volatile memories include, but are not limited to, a Read Only Memory (ROM) 1124, an electrically programmable read only memory (EPROM) , a flash memory, a hard disk, a compact disc (CD) , a digital video disk (DVD) , and other magnetic storage and/or optical storage. Examples of the volatile memories include, but are not limited to, a random access memory (RAM) 1122 and other volatile memories that will not last in the power-down duration.

A computer program 1130 includes computer executable instructions that are executed by the associated processor 1110. The program 1130 may be stored in the ROM 1124. The processor 1110 may perform any suitable actions and processing by loading the program 1130 into the RAM 1122.

The embodiments of the present disclosure may be implemented by means of the program 1130 so that the device 1100 may perform any process of the disclosure as discussed with reference to FIGs. 3-6. The embodiments of the present disclosure may also be implemented by hardware or by a combination of software and hardware.

In some embodiments, the program 1130 may be tangibly contained in a computer readable medium which may be included in the device 1100 (such as in the memory 1120) or other storage devices that are accessible by the device 1100. The device 1100 may load the program 930 from the computer readable medium to the RAM 1122 for execution. The computer readable medium may include any types of tangible non-volatile storage, such as ROM, EPROM, a flash memory, a hard disk, CD, DVD, and the like.

FIG. 12 shows an example of the computer readable medium 1200 in form of CD or DVD. The computer readable medium has the program 1130 stored thereon.

Generally, various embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device. While various aspects of embodiments of the present disclosure are illustrated and described as block diagrams, flowcharts, or using some other pictorial representations, it is to be understood that the block, device, system, technique or method described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer readable storage medium. The computer program product includes computer-executable instructions, such as those included in program modules, being executed in a device on a target real or virtual processor, to carry out the methods 700 to 1000 as described above with reference to FIGs. 7 to 10. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, or the like that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split between program modules as desired in various embodiments. Machine-executable instructions for program modules may be executed within a local or distributed device. In a distributed device, program modules may be located in both local and remote storage media.

Program code for carrying out methods of the present disclosure may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing device, such that the program codes, when executed by the processor or controller, cause the functions/operations specified in the flowcharts and/or block diagrams to be implemented. The program code may execute entirely on a machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.

In the context of the present disclosure, the computer program codes or related data may be carried by any suitable carrier to enable the device, device or processor to perform various processes and operations as described above. Examples of the carrier include a signal, computer readable medium, and the like.

The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable medium may include but not limited to an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, device, or device, or any suitable combination of the foregoing. More specific examples of the computer readable storage medium would include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM) , a read-only memory (ROM) , an erasable programmable read-only memory (EPROM or Flash memory) , an optical fiber, a portable compact disc read-only memory (CD-ROM) , an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

Further, while operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Likewise, while several specific implementation details are contained in the above discussions, these should not be construed as limitations on the scope of the present disclosure, but rather as descriptions of features that may be specific to particular embodiments. Certain features that are described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment may also be implemented in multiple embodiments separately or in any suitable sub-combination.

Although the present disclosure has been described in languages specific to structural features and/or methodological acts, it is to be understood that the present disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

A first terminal device, comprising:

at least one processor; and

at least one memory including computer program codes;

the at least one memory and the computer program codes are configured to, with the at least one processor, cause the first terminal device at least to:

in accordance with a determination that the first terminal device and a first network device roam from a first network to a second network, transmit a roaming indication to a second network device associated with the second network, the first terminal device and the first network device acting as an integrated access and backhaul, IAB, node in the first network; and

cause the roaming of the first network device to be authorized by a third network device of the second network.
The first terminal device of Claim 1, wherein the parameters associated with the second network are preconfigured at the first network device, and the parameters are activated upon the roaming of the first network device is authorized.
The first terminal device of Claim 1, wherein the parameters associated with the second network are preconfigured at the second network device, and provided to the first network device upon the roaming is authorized.
The first terminal device of Claim 1, wherein the at least one memory and the computer program codes are configured to, with the at least one processor, further cause the first terminal device to:

receive, from the second network, a message comprising a name or an address for an operation administration and maintenance, OAM, node and authentication information for OAM transaction in the second network.
The first terminal device of Claim 1, wherein the third network device comprises a core network device of the second network, and the parameters are determined by the core network or an operation administration and maintenance, OAM, node of the second network.
A first network device, comprising:

at least one processor; and

at least one memory including computer program codes;

the at least one memory and the computer program codes are configured to, with the at least one processor, cause the first network device at least to:

in accordance with a determination that a roaming from a first network to a second network is authorized by a third network device of the second network, obtain parameters associated with the second network, the first network device and a first terminal device acting as an integrated access and backhaul, IAB, node in the second network; and

enable a communication of a terminal device in the second network based on the parameters associated with the second network, the terminal device being connected to the first network device.
The first network device of Claim 6, wherein the parameters are obtained via a F1 procedure with a second network device of the second network, and the second network device comprises an integrated access and backhaul, IAB, donor of the second network.
The first network device of Claim 7, wherein the at least one memory and the computer program codes are configured to, with the at least one processor, cause the first network device to obtain the parameters by:

transmitting, to the second network device, a F1 setup request comprising parameters associated with the first network; and

receiving, from the second network device, a F1 setup response comprising the parameters associated with the second network.
The first network device of Claim 6, wherein the at least one memory and the computer program codes are configured to, with the at least one processor, cause the first network device to obtain the parameters by:

in accordance with a determination that the roaming is authorized, activating the parameters associated with the second network, the parameters being preconfigured at the first network device.
The first network device of Claim 6, wherein the third network device comprises a core network device of the second network and the parameters are determined by the core network device based on a type of the first network device.
The first network device of Claim 6, wherein the parameters are obtained from an operation administrator and maintenance, OAM, node of the second network.
A second network device, comprising:

at least one processor; and

at least one memory including computer program codes;

the at least one memory and the computer program codes are configured to, with the at least one processor, cause the second network device at least to:

receive, from a first terminal device, a roaming indication of the first terminal device and a first network device roaming from a first network to a second network, the second network device being associated with the second network, and the first terminal device and the first network device acting as an integrated access and backhaul, IAB, node in the second network;

select, based on the roaming indication, a third network device of the second network for determining whether the first network device is authorized to roam in the second network; and

in accordance with a determination that the roaming of the first network device is authorized, configuring the first network device to be a network device of the second network.
The second network device of Claim 12, wherein the at least one memory and the computer program codes are configured to, with the at least one processor, further cause the second network device to:

transmit a first message comprising the roaming indication to the third network device;

receive, from the third network device, a second message comprising a roaming authorization indication; and

determine whether the first network device is authorized based on the roaming authorization indication.
The second network device of Claim 13, wherein the first message comprises a registration message, and the second message comprises roaming restrictions and access restrictions.
The second network device of Claim 14, wherein the roaming authorization indication comprises an identification of the first network.
The second network device of Claim 15, wherein the at least one memory and the computer program codes are configured to, with the at least one processor, further cause the second network device to:

determine parameters based on the identification of the first network; and

transmit parameters to be used in the second network to the first network device.
The second network device of Claim 13, wherein the at least one memory and the computer program codes are configured to, with the at least one processor, further cause the second network device to:

transmit, to the first terminal network, a message comprising a name or an IP address for an operation administration and maintenance, OAM, node and authentication information for OAM transaction in the second network, and the parameters are determined by the OAM node.
The second network device of Claim 13, wherein the parameters associated with the second network are preconfigured at the second network device, and the parameters are determined based on a type of the first network device.
A third network device, comprising:

at least one processor; and

at least one memory including computer program codes;

the at least one memory and the computer program codes are configured to, with the at least one processor, cause the third network device at least to:

receive, from a second network device of a second network, a first message comprising a roaming indication of a first terminal device and a first network device roaming from a first network to the second network, the third network device being associated with the second network, and the first terminal device and the first network device acting as an integrated access and backhaul, IAB, node in the first network; and

in accordance with a determination that the first network device is authorized to roam in the second network, transmit, to the second network device, a second message comprising a roaming authorization indication.
The third network device of Claim 19, wherein the transmission of the roaming authorization indication causes the second network device to configure the first network device to be a network device of the second network.
The third network device of Claim 20, wherein the roaming authorization indication comprises an identification of the first network, parameters corresponding to identification of the first network is preconfigured at the second network device, and the transmission of the roaming authorization indication causes the second network device to configure the first network device with the parameters associated with the second network.
An integrated access and backhaul, IAB, node comprising:

a first terminal device according to any of Claims 1 to 5; and

a first network device according to any of Claims 6 to 11.
A method comprising:

in accordance with a determination that the first terminal device and a first network device roam from a first network to a second network, transmitting, at a first terminal device, a roaming indication to a second network device associated with the second network, the first terminal device and the first network device acting as an integrated access and backhaul, IAB, node in the first network;

causing the roaming of the first network device to be authorized by a third network device of the second network; and

communicating in the second network via the first terminal device, the first network device operating based on parameters associated with the second network.
A method comprising:

in accordance with a determination that a roaming from a first network to a second network is authorized by a third network device of the second network, obtaining, at a first network device, parameters associated with the second network, the first network device and a first terminal device acting as an integrated access and backhaul, IAB, node in the second network; and

enabling a communication of a terminal device in the second network based on the parameters associated with the second network, the terminal device being connected to the first network device.
A method comprising:

receiving, at a second network device and from a first terminal device, a roaming indication of the first terminal device and a first network device roaming from a first network to a second network, the second network device being associated with the second network, and the first terminal device and the first network device acting as an integrated access and backhaul, IAB, node in the second network;

selecting, based on the roaming indication, a third network device of the second network for determining whether the first network device is authorized to roam in the second network; and

in accordance with a determination that the roaming of the first network device is authorized, configuring the first network device to be a network device of the second network.
A method comprising:

receiving, at a third network device and from a second network device of a second network, a first message comprising a roaming indication of a first terminal device and a first network device roaming from a first network to the second network, the third network device being associated with the second network, and the first terminal device and the first network device acting as an integrated access and backhaul, IAB, node in the first network; and

in accordance with a determination that the first network device is authorized to roam in the second network, transmitting, to the second network device, a second message comprising a roaming authorization indication.
A first terminal apparatus comprising:

means for in accordance with a determination that the first terminal apparatus and a first network apparatus roams from a first network to a second network, transmitting, at a first terminal apparatus, a roaming indication to a second network apparatus associated with the second network, the first terminal apparatus and the first network apparatus acting as an integrated access and backhaul, IAB, node in the first network;

means for causing the roaming of the first network apparatus to be authorized by a third network apparatus of the second network; and

means for communicating in the second network via the first terminal apparatus, the first network apparatus operating based on parameters associated with the second network.
A first network apparatus comprising:

means for in accordance with a determination that a roaming from a first network to a second network is authorized by a third network apparatus of the second network, obtaining, at a first network apparatus, parameters associated with the second network, the first network apparatus and a first terminal apparatus acting as an integrated access and backhaul, IAB, node in the second network; and

means for enabling a communication of a terminal device in the second network based on the parameters associated with the second network, the terminal device being connected to the first network apparatus.
A second network apparatus comprising:

means for receiving, at a second network apparatus and from a first terminal apparatus, a roaming indication of the first terminal apparatus and a first network apparatus roaming from a first network to a second network, the second network apparatus being associated with the second network, and the first terminal apparatus and the first network apparatus acting as an integrated access and backhaul, IAB, node in the second network;

means for selecting, based on the roaming indication, a third network apparatus of the second network for determining whether the first network apparatus is authorized to roam in the second network; and

means for in accordance with a determination that the roaming of the first network apparatus is authorized, configuring the first network apparatus to be a network device of the second network.
A third network apparatus comprising:

means for receiving, at a third network apparatus and from a second network apparatus of a second network, a first message comprising a roaming indication of a first terminal apparatus and a first network apparatus roaming from a first network to the second network, the third network apparatus being associated with the second network, and the first terminal apparatus and the first network apparatus acting as an integrated access and backhaul, IAB, node in the first network; and

means for in accordance with a determination that the first network apparatus is authorized to roam in the second network, transmitting, to the second network apparatus, a second message comprising a roaming authorization indication.
A computer readable medium comprising program instructions for causing an apparatus to perform at least any of the methods of Claims 23 to 26.