WO2024152617A1

WO2024152617A1 - Method and apparatus for du migration of an iab node

Info

Publication number: WO2024152617A1
Application number: PCT/CN2023/122610
Authority: WO
Inventors: Yibin ZHUO; Mingzeng Dai; Lianhai WU
Original assignee: Lenovo Beijing Ltd
Current assignee: Lenovo Beijing Ltd
Priority date: 2023-09-28
Filing date: 2023-09-28
Publication date: 2024-07-25
Anticipated expiration: 2026-03-28
Also published as: WO2024152617A9

Abstract

Embodiments of the present disclosure relate to a method and apparatus for distributed unit (DU) migration of an integrated access and backhaul (IAB) node. According to some embodiments of the disclosure, a wireless network node may: transmit an F1 setup request message to a first base station (BS), the F1 setup request message being for performing a DU migration of the wireless network node from a second BS to the first BS, and wherein the F1 setup request message includes information relating to a UE traffic profile of one or more UEs as served by the wireless network node; and in response to transmitting the F1 setup request message, receive a response message to the F1 setup request message from the first BS.

Description

METHOD AND APPARATUS FOR DU MIGRATION OF AN IAB NODE

TECHNICAL FIELD

Embodiments of the present disclosure generally relate to wireless communication technology, and more particularly to distributed unit (DU) migration of an integrated access and backhaul (IAB) node.

BACKGROUND

A wireless communication system may include one or multiple network communication devices, such as base stations, which may support wireless communication for one or multiple user communication devices, which may be otherwise known as user equipment (UE) , or other suitable terminology. The wireless communication system may support wireless communication with one or multiple user communication devices by utilizing resources of the wireless communication system (e.g., time resources (e.g., symbols, slots, subframes, frames, or the like) or frequency resources (e.g., subcarriers, carriers, or the like) . Additionally, the wireless communication system may support wireless communication across various radio access technologies including third generation (3G) radio access technology, fourth generation (4G) radio access technology, fifth generation (5G) (which is also known as new radio (NR) ) radio access technology, among other suitable radio access technologies beyond 5G (e.g., sixth generation (6G) ) .

To extend the coverage and availability of wireless communication systems, the 3rd generation partnership project (3GPP) is envisioning IAB architecture for supporting multi-hop relays. In an IAB network, an IAB node may hop through one or more IAB nodes before reaching a base station (also referred to as “an IAB donor” or “a donor node” ) . A single hop may be considered a special instance of multiple hops. Multi-hop backhauling is beneficial because it provides a relatively greater coverage extension compared to single-hop backhauling. In a relatively high frequency radio communication system (e.g., radio signals transmitted in frequency bands over 6 GHz) , relatively narrow or less signal coverage may benefit from multi-hop backhauling techniques.

The industry desires technologies for facilitating communications in an IAB network. The industry desires technologies for facilitating DU migration of an IAB node.

SUMMARY

An article "a" before an element is unrestricted and understood to refer to "at least one" of those elements or "one or more" of those elements. The terms "a, " "at least one, " "one or more, " and "at least one of one or more" may be interchangeable. As used herein, including in the claims, "or" as used in a list of items (e.g., a list of items prefaced by a phrase such as "at least one of" or "one or more of" or "one or both of" ) indicates an inclusive list such that, for example, a list of at least one of A, B, or C means A or B or C or AB or AC or BC or ABC (i.e., A and B and C) . Also, as used herein, the phrase "based on" shall not be construed as a reference to a closed set of conditions. For example, an example step that is described as "based on condition A" may be based on both a condition A and a condition B without departing from the scope of the present disclosure. In other words, as used herein, the phrase "based on" shall be construed in the same manner as the phrase "based at least in part on. " Further, as used herein, including in the claims, a "set" may include one or more elements.

Some embodiments of the present disclosure provide a wireless network node. The wireless network node may include: at least one memory; and at least one processor coupled with the at least one memory and configured to cause the wireless network node to: transmit an F1 setup request message to a first base station (BS) , the F1 setup request message being for performing a distributed unit (DU) migration of the wireless network node from a second BS to the first BS, and wherein the F1 setup request message includes information relating to a user equipment (UE) traffic profile of one or more UEs as served by the wireless network node; and in response to transmitting the F1 setup request message, receive a response message to the F1 setup request message from the first BS.

In some embodiments of the present disclosure, the information relating to the UE traffic profile indicates: the number of UEs connected to the wireless network node; the number of UEs connected to the wireless network node and located inside a vehicle on which the wireless network node is mounted; the number of UEs connected to the wireless network node and located outside the vehicle on which the wireless network node is mounted; a volume of downlink traffic for all UEs connected to the wireless network node; a volume of uplink traffic for all UEs connected to the wireless network node; a volume of downlink traffic for all UEs connected to the wireless network node and located inside the vehicle on which the wireless network node is mounted; a volume of uplink traffic for all UEs connected to the wireless network node and located inside the vehicle on which the wireless network node is mounted; a volume of downlink traffic for all UEs connected to the wireless network node and located outside the vehicle on which the wireless network node is mounted; a volume of uplink traffic for all UEs connected to the wireless network node and located outside the vehicle on which the wireless network node is mounted; a bit rate for downlink traffic; a bit rate for uplink traffic; or any combination thereof.

In some embodiments of the present disclosure, the bit rate includes a guaranteed flow bit rate (GFBR) or a maximum flow bit rate (MFBR) .

In some embodiments of the present disclosure, the response message is an F1 setup response message which indicates: the number of UEs allowed to be handed over from the second BS to the first BS; a volume of downlink traffic allowed; or a volume of uplink traffic allowed.

In some embodiments of the present disclosure, the at least one processor is further configured to cause the wireless network node to transmit an F1 setup outcome notification message to the second BS based on the F1 setup response message.

In some embodiments of the present disclosure, the F1 setup outcome notification message indicates: the number of UEs allowed to be handed over from the second BS to the first BS; a volume of downlink traffic allowed; or a volume of uplink traffic allowed.

In some embodiments of the present disclosure, the response message is an F1 setup failure message which indicates: a cause value of the F1 setup failure; or a waiting time before reinitiating another F1 setup procedure or another DU migration procedure to the first BS.

In some embodiments of the present disclosure, the at least one processor is further configured to cause the wireless network node to transmit an F1 setup outcome notification message to the second BS based on the F1 setup failure message.

In some embodiments of the present disclosure, the F1 setup outcome notification message indicates: a cause value of the F1 setup failure; or a waiting time before reinitiating another F1 setup procedure or another DU migration procedure to the first BS.

Some embodiments of the present disclosure provide a first BS. The first BS may include: at least one memory; and at least one processor coupled with the at least one memory and configured to cause the first BS to: receive an F1 setup request message from a wireless network node, the F1 setup request message being for performing a DU migration of the wireless network node from a second BS to the first BS, and wherein the F1 setup request message includes information relating to a UE traffic profile of one or more UEs as served by the wireless network node; and transmit, to the wireless network node, a response message to the F1 setup request message, in response to receiving the F1 setup request message.

In some embodiments of the present disclosure, the bit rate includes a GFBR or an MFBR.

Some embodiments of the present disclosure provide a second BS. The second BS may include: at least one memory; and at least one processor coupled with the at least one memory and configured to cause the second BS to: initiate a DU migration of a wireless network node from the second BS to a first BS; and receive an F1 setup outcome notification message from the wireless network node, wherein the F1 setup outcome notification message indicates: a cause value of an F1 setup failure associated with the DU migration of the wireless network node, or a waiting time before reinitiating another F1 setup procedure or another DU migration procedure to the first BS.

Some embodiments of the present disclosure provide a method for wireless communication, including: transmitting an F1 setup request message to a first BS, the F1 setup request message being for performing a DU migration of the wireless network node from a second BS to the first BS, and wherein the F1 setup request message includes information relating to a UE traffic profile of one or more UEs as served by the wireless network node; and in response to transmitting the F1 setup request message, receiving a response message to the F1 setup request message from the first BS.

In some embodiments of the present disclosure, the method further include transmitting an F1 setup outcome notification message to the second BS based on the response message.

Some embodiments of the present disclosure provide an apparatus. According to some embodiments of the present disclosure, the apparatus may include: at least one non-transitory computer-readable medium having stored thereon computer-executable instructions; at least one receiving circuitry; at least one transmitting circuitry; and at least one processor coupled to the at least one non-transitory computer-readable medium, the at least one receiving circuitry and the at least one transmitting circuitry, wherein the at least one non-transitory computer-readable medium and the computer executable instructions may be configured to, with the at least one processor, cause the apparatus to perform a method according to some embodiments of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to describe the manner in which the advantages and features of the disclosure can be obtained, a description of the disclosure is rendered by reference to specific embodiments thereof, which are illustrated in the appended drawings. These drawings depict only exemplary embodiments of the disclosure and are not therefore to be considered limiting of its scope.

FIG. 1 illustrates a schematic diagram of a wireless communication system in accordance with some embodiments of the present disclosure;

FIGs. 2A and 2B illustrate example block diagrams of a protocol stack for an IAB network in accordance with some embodiments of the present disclosure;

FIG. 3 illustrates an exemplary DU migration procedure in accordance with some embodiments of the present disclosure;

FIGs. 4 and 5 illustrate flow charts of exemplary DU migration procedures in accordance with some embodiments of the present disclosure;

FIGs. 6, 7 and 7A illustrate flowcharts of methods for wireless communication in accordance with some embodiments of the present disclosure;

FIG. 8 illustrates an example of a network equipment (NE) in accordance with some embodiments of the present disclosure; and

FIG. 9 illustrates an example of a processor in accordance with some embodiments of the present disclosure.

DETAILED DESCRIPTION

The detailed description of the appended drawings is intended as a description of the preferred embodiments of the present disclosure and is not intended to represent the only form in which the present disclosure may be practiced. It should be understood that the same or equivalent functions may be accomplished by different embodiments that are intended to be encompassed within the spirit and scope of the present disclosure.

Reference will now be made in detail to some embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. To facilitate understanding, embodiments are provided under a specific network architecture (s) and new service scenarios, such as the 3rd generation partnership project (3GPP) 5G NR or 6G, 3GPP LTE, and so on. It is contemplated that along with the developments of network architectures and new service scenarios, all embodiments in the present disclosure are also applicable to similar technical problems; and moreover, the terminologies recited in the present disclosure may change, which should not affect the principles of the present disclosure.

Compared with the 4G communication system, the 5G communication system has raised more stringent requirements for various network performance indicators, for example, a 1000-time capacity increase, wider coverage requirements, ultra-high reliability, ultra-low latency, etc. Considering the rich frequency resources of high-frequency carriers, the use of high-frequency small station deployments is becoming more and more popular in hotspot areas in order to meet the needs of 5G ultra-high capacity. However, high-frequency carriers have poor propagation characteristics, severe attenuation due to obstructions, and limited coverage. Therefore, the dense deployment of small stations is required. In addition, the deployment of optical fiber may be difficult and costly for these small stations. Therefore, an economical and convenient backhaul scheme is needed. IAB technology, whose access link (s) and backhaul link (s) may both use wireless transmission solutions to avoid fiber deployment, provides ideas for solving the above problems.

In an IAB network, a wireless network node such as a relay node (RN) or an IAB node or a wireless backhaul node/device can provide wireless access services for UEs. For example, a UE can connect to an IAB donor relayed by one or more IAB nodes. The IAB donor may also be called a donor node or a donor base station (e.g., DgNB, Donor gNodeB) . In addition, the wireless link between an IAB donor and an IAB node, or the wireless link between different IAB nodes can be referred to as a “backhaul link. ” The wireless network node in an IAB network may be stationary or mobile. Embodiments of the present disclosure can be applied to the wireless network node regardless of whether it is stationary or mobile.

An IAB node may include an IAB mobile terminal (MT) part and an IAB distributed unit (DU) part. When an IAB node connects to its parent node (which may be another IAB node or an IAB donor) , it can be regarded as a UE, i.e., the role of an MT. When an IAB node provides service to its child node (which may be another IAB node or a UE) , it can be regarded as a network device, i.e., the role of a DU.

An IAB donor can be an access network element with a complete base station function, or an access network element with a separate form of a centralized unit (CU) and a DU. The IAB donor may be connected to the core network (for example, connected to the 5G core (5GC) network) , and provide the wireless backhaul function for the IAB nodes. The CU of an IAB donor may be referred to as an “IAB donor-CU” (or directly referred to as a “CU” ) , and the DU of the IAB donor may be referred to as an “IAB donor-DU. ” The IAB donor-CU may be separated into a control plane (CP) and a user plane (UP) . For example, a CU may include one CU-CP and one or more CU-UPs.

Considering the limited coverage of a high frequency band, and in order to ensure coverage performance of the network, multi-hop networking may be adopted in an IAB network. Taking into account the requirements of service transmission reliability, IAB nodes can support dual connectivity (DC) or multi-connectivity to improve transmission reliability, so as to deal with abnormal situations that may occur on the backhaul (BH) link, such as radio link failure (RLF) or blockage, load fluctuations, etc.

In the case where an IAB network supports multi-hop and dual-connection networking, there may be multiple transmission paths between the UE and the IAB donor. A transmission path may include multiple nodes, such as a UE, one or more IAB nodes, and an IAB donor (if the IAB donor is in the form of a separate CU and DU, it may also contain an IAB donor-DU and an IAB donor-CU) . Each IAB node may treat the neighboring node that provides backhaul services for it as a parent node (or parent IAB node) , and each IAB node can be regarded as a child node (or child IAB node) of its parent node.

Improvements to an IAB network are desired. For example, various issues may occur during the DU migration of an IAB node from a source IAB donor to a target IAB donor. For example, UEs served by the IAB node need to be handed over from the source IAB donor to the target IAB donor. In certain cases, the target IAB donor may refuse the UE handover due to, for example, traffic overload and that the UE (s) loses connection to the source IAB donor because F1 connection between the IAB node and the source IAB donor will be release after the DU migration. Enhancement is required to facilitate the DU migration to avoid traffic interruption of the UEs as served by the IAB node. For example, when the source IAB donor triggers the DU migration of the IAB node, the source IAB donor may only have limited information of the outcome of the F1 setup during the DU migration. It would be beneficial if the source IAB donor can have more information in the case of a failed F1 setup.

Embodiments of the present disclosure provide solutions for facilitating the DU migration of an IAB node. By adopting the proposed solutions, admission control for the DU migration of the wireless network node can be enhanced and smarter DU migration can be achieved.

FIG. 1 illustrates a schematic diagram of wireless communication system 100 in accordance with some embodiments of the present disclosure.

As shown in FIG. 1, wireless communication system 100 may include some base stations (e.g., IAB donor 110A and IAB donor 110B) , some IAB nodes (e.g., IAB node 120A, IAB node 120B, and IAB node 120C) , and some UEs (e.g., UE 130A and UE 130B) . Although a specific number of UEs, IAB nodes, and IAB donors is depicted in FIG. 1, it is contemplated that any number of UEs, IAB nodes, and IAB donors may be included in wireless communication system 100. Each of IAB donor 110A, IAB donor 110B, IAB node 120A, IAB node 120B, and IAB node 120C may be directly connected to one or more IAB nodes in accordance with some other embodiments of the present disclosure. Each of IAB donor 110A, IAB donor 110B, IAB node 120A, IAB node 120B, and IAB node 120C may be directly connected to one or more UEs in accordance with some other embodiments of the present disclosure.

Wireless communication system 100 may be compatible with any type of network that is capable of transmitting and receiving wireless communication signals. Wireless communication system 100 may support various radio access technologies. In some implementations, wireless communication system 100 may be a 4G network, such as an LTE network or an LTE-Advanced (LTE-A) network. In some other implementations, wireless communication system 100 may be a NR network, such as a 5G network, a 5G-Advanced (5G-A) network, or a 5G ultra-wideband (5G-UWB) network. In other implementations, wireless communication system 100 may be a combination of a 4G network and a 5G network, or other suitable radio access technology including Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi) , IEEE 802.16 (WiMAX) , and IEEE 802.20. Wireless communication system 100 may support radio access technologies beyond 5G, for example, 6G. Additionally, wireless communication system 100 may support technologies, such as time division multiple access (TDMA) , frequency division multiple access (FDMA) , or code division multiple access (CDMA) , etc.

In the context of the present disclosure, an IAB node (e.g., IAB node 120A, IAB node 120B, or IAB node 120C in FIG. 1) or an IAB donor (e.g., IAB donor 110A and IAB donor 110B in FIG. 1) may also be referred to an NE. An NE may be dispersed throughout a geographic region to form wireless communication system 100. An NE may provide a geographic coverage area for which the NE may support services for one or more UEs within the geographic coverage area. For example, an NE and a UE may support wireless communication of signals related to services (e.g., voice, video, packet data, messaging, broadcast, etc. ) according to one or multiple radio access technologies. In some implementations, an NE may be moveable, for example, a satellite associated with a non-terrestrial network (NTN) or a relay mounted on a moving vehicle. In some implementations, different geographic coverage areas associated with the same or different radio access technologies may overlap, but the different geographic coverage areas may be associated with a different NE.

UE 130A and UE 130B may be dispersed throughout a geographic region of wireless communication system 100. UE 130A and UE 130B may be any type of device configured to operate and/or communicate in a wireless environment. For example, UE 130A or UE 130B may include or may be referred to as a remote unit, a mobile device, a wireless device, a remote device, a subscriber device, a transmitter device, a receiver device, or some other suitable terminology. In some implementations, UE 130A or UE 130B may be referred to as a unit, a station, a terminal, or a client, among other examples. Additionally, or alternatively, UE 130A or UE 130B may be referred to as an Internet-of-Things (IoT) device, an Internet-of-Everything (IoE) device, or machine-type communication (MTC) device, among other examples.

An IAB donor may support communication with a core network (CN) , or with another IAB donor, or both. For example, IAB donor 110A may interface with IAB donor 110B or the CN (not shown in FIG. 1) through one or more backhaul links (e.g., S1, X2, NG, Xn, or other network interface) . In some implementations, IAB donors may communicate with each other directly. In some other implementations, IAB donors may communicate with each other indirectly (e.g., via the CN) .

The CN may support user authentication, access authorization, tracking, connectivity, and other access, routing, or mobility functions. The CN may be an evolved packet core (EPC) , or a 5G core (5GC) , which may include a control plane entity that manages access and mobility (e.g., a mobility management entity (MME) , an access and mobility management functions (AMF) ) and a user plane entity that routes packets or interconnects to external networks (e.g., a serving gateway (S-GW) , a Packet Data Network (PDN) gateway (P-GW) , or a user plane function (UPF) ) . In some implementations, the control plane entity may manage non-access stratum (NAS) functions, such as mobility, authentication, and bearer management (e.g., data bearers, signal bearers, etc. ) for UEs served by an IAB node or an IAB donor associated with the CN.

The CN may communicate with a packet data network over one or more backhaul links (e.g., via an N6 or another network interface) . The packet data network may include an application server. In some implementations, one or more UEs may communicate with the application server. A UE may establish a session (e.g., a protocol data unit (PDU) session, or the like) with the CN via, for example, an IAB donor. The CN may route traffic (e.g., control information, data, and the like) between the UE and the application server using the established session (e.g., the established PDU session) . The PDU session may be an example of a logical connection between the UE and the CN (e.g., one or more network functions of the CN) .

In wireless communication system 100, NEs (e.g., IAB donors and IAB nodes) and UEs may use resources of wireless communication system 100 (e.g., time resources (e.g., symbols, slots, subframes, frames, or the like) or frequency resources (e.g., subcarriers, carriers) ) to perform various operations (e.g., wireless communication) .

In wireless communication system 100, an electromagnetic (EM) spectrum may be split, based on frequency or wavelength, into various classes, frequency bands, frequency channels, etc. By way of example, wireless communication system 100 may support one or multiple operating frequency bands, such as frequency range designations FR1 (410 MHz –7.125 GHz) , FR2 (24.25 GHz –52.6 GHz) , FR3 (7.125 GHz –24.25 GHz) , FR4 (52.6 GHz –114.25 GHz) , FR4a or FR4-1 (52.6 GHz –71 GHz) , and FR5 (114.25 GHz –300 GHz) . In some implementations, NEs and UEs may perform wireless communication over one or more of the operating frequency bands. In some implementations, FR1 may be used by NEs and UEs, among other equipment or devices for cellular communication traffic (e.g., control information, data) . In some implementations, FR2 may be used by NEs and UEs, among other equipment or devices for short-range, high data rate capabilities.

A UE may include computing devices, such as desktop computers, laptop computers, personal digital assistants (PDAs) , tablet computers, smart televisions (e.g., televisions connected to the Internet) , set-top boxes, game consoles, security systems (including security cameras) , vehicle on-board computers, network devices (e.g., routers, switches, and modems) , vehicles or the like. According to some embodiments of the present disclosure, a UE may include a portable wireless communication device, a smart phone, a cellular telephone, a flip phone, a device having a subscriber identity module, a personal computer, a selective call receiver, or any other device that is capable of sending and receiving communication signals on a wireless network. In some embodiments of the present disclosure, a UE includes wearable devices, such as smart watches, fitness bands, optical head-mounted displays, or the like. Moreover, a UE may be referred to as a subscriber unit, a mobile, a mobile station, a user, a terminal, a mobile terminal, a wireless terminal, a fixed terminal, a subscriber station, a user terminal, or a device, or described using other terminology used in the art. A UE may communicate with an NE (e.g., an IAB donor or an IAB node) via uplink (UL) communication signals. An NE may communicate with a UE via downlink (DL) communication signals.

In some embodiments of the present disclosure, an NE (e.g., a wireless network node, a BS, an IAB donor or an IAB node) and a UE may communicate over licensed spectrums, whereas in some other embodiments, an NE and a UE may communicate over unlicensed spectrums. The present disclosure is not intended to be limited to the implementation of any particular wireless communication system architecture or protocol.

Persons skilled in the art should understand that as technology develops and advances, the terminologies described in the present disclosure may change, but should not affect or limit the principles and spirit of the present disclosure.

Referring to FIG. 1, IAB node 120A can be directly connected to IAB donors 110A and 110B, and IAB node 120B can be directly connected to IAB donor 110A. IAB donors 110A and 110B are parent nodes of IAB node 120A, and IAB donor 110A is a parent node of IAB node 120B. In other words, IAB nodes 120A and 120B are child IAB nodes of IAB donor 110A, and IAB node 120A is also a child IAB node of IAB donor 110B. IAB node 120C can reach IAB donor 110A by hopping through IAB node 120B. IAB node 120B is a parent IAB node of IAB node 120C. In other words, IAB node 120C is a child IAB node of IAB node 120B.

In some other embodiments of the present disclosure, an IAB node may be connected to IAB node 120C so it can reach IAB donor 110A by hopping through IAB node 120C and IAB node 120B. This IAB node and IAB node 120C may be referred to as the descendant IAB nodes of IAB node 120B.

UEs 130A and 130B can be connected to IAB nodes 120A and 120C, respectively. IAB nodes 120A and 120C may therefore be referred to as access IAB nodes. UL packets (e.g., data or signaling) from UE 130A or UE 130B can be transmitted to an IAB donor (e.g., IAB donor 110A or 110B) via one or more IAB nodes, and then transmitted by the IAB donor to a mobile gateway device (such as the UPF in the 5GC) . DL packets (e.g., data or signaling) can be transmitted from the IAB donor (e.g., IAB donor 110A or 110B) after being received by the gateway device, and then transmitted to UE 130A or 130B through one or more IAB nodes.

For example, referring to FIG. 1, UE 130A may transmit UL data to IAB donor 110A or 110B or receive DL data therefrom via IAB node 120A. UE 130B may transmit UL data to IAB donor 110A or receive DL data therefrom via IAB node 120C and IAB node 120B.

In an IAB deployment such as the wireless communication system 100, the radio link between an IAB donor (e.g., IAB donor 110A or 110B in FIG. 1) and an IAB node or between two IAB nodes may be referred to as a backhaul link (BL) . The radio link between an IAB donor (e.g., IAB donor 110A or 110B in FIG. 1) and a UE or between an IAB node and a UE may be referred to as an access link (AL) . For example, in FIG. 1, radio links 140A to 140D are BLs and radio links 150A and 150B are ALs.

A protocol layer, the backhaul adaptation protocol (BAP) layer, located above the radio link control (RLC) layer, is introduced in an IAB system and can be used to realize packet routing, bearer mapping and flow control on a wireless backhaul link.

An F1 interface may be established between an IAB node (e.g., DU part of the IAB node) and an IAB donor (e.g., IAB donor-CU) . The F1 interface may support both a user plane protocol (e.g., F1-U) and a control plane protocol (e.g., F1-C) . The user plane protocol of the F1 interface may include one or more of a general packet radio service (GPRS) tunneling protocol user plane (GTP-U) , user datagram protocol (UDP) , internet protocol (IP) and other protocols. The control plane protocol of the F1 interface may include one or more of an F1 application protocol (F1AP) , stream control transport protocol (SCTP) , IP, and other protocols.

Through the control plane of the F1 interface, an IAB node and an IAB donor can perform, for example, interface management, IAB-DU management, and a UE context-related configuration. Through the user plane of the F1 interface, an IAB node and an IAB donor can perform, for example, user plane data transmission and downlink transmission status feedback functions.

FIG. 2A illustrates an example block diagram of user plane (UP) protocol stack 200A for an IAB network according to some embodiments of the present disclosure. FIG. 2B illustrates an example block diagram of control plane (CP) protocol stack 200B for an IAB network according to some embodiments of the present disclosure. In FIGs. 2A and 2B, a UE may be connected to an IAB donor via IAB node 2 and IAB node 1. In some other embodiments of the present disclosure, a UE may be connected to an IAB donor via more or less IAB nodes.

Referring to FIG. 2A, the UP protocol stack of the UE may include a service data adaptation protocol (SDAP) layer, a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, a medium access control (MAC) layer, and a physical (PHY) layer. The UP protocol stack of the DU of IAB node 2 may include a GTP-U layer, a UDP layer, an IP layer, an RLC layer, a MAC layer, and a PHY layer. The UP protocol stack of the MT of IAB node 2 or the DU or MT of IAB node 1 may include a BAP layer, an RLC layer, a MAC layer, and a PHY layer. The UP protocol stack of the DU of the IAB donor may include an IP layer, a BAP layer, an RLC layer, a MAC layer, and a PHY layer, where the PHY layer belongs to layer 1 (L1) , and the BAP layer, the RLC layer, and the MAC layer belong to layer 2 (L2) . The protocol stack of the CU-UP of the IAB donor may include a GTP-U layer, a UDP layer, an IP layer, an SDAP layer, a PDCP layer, an L2 layer (s) , and an L1 layer.

Referring to FIG. 2B, the CP protocol stack of the UE may include a radio resource control (RRC) layer, a PDCP layer, an RLC layer, a MAC layer, and a physical (PHY) layer. The CP protocol stack of the DU of IAB node 2 may include an F1AP layer, an SCTP layer, an IP layer, an RLC layer, a MAC layer, and a PHY layer. The CP protocol stack of the MT of IAB node 2 or the DU or MT of IAB node 1 may include a BAP layer, an RLC layer, a MAC layer, and a PHY layer. The CP protocol stack of the DU of the IAB donor may include an IP layer, a BAP layer, an RLC layer, a MAC layer, and a PHY layer, where the PHY layer belongs to L1, and the BAP layer, the RLC layer, and the MAC layer belong to L2. The protocol stack of the CU-CP of the IAB donor may include an RRC layer, a PDCP layer, an F1AP layer, an SCTP layer, an IP layer, an L2 layer (s) , and an L1 layer.

The protocol stacks shown in FIGs. 2A and 2B are only for illustrative purposes. For example, the sequences of some of the protocol layers in the protocol stacks of FIGs. 2A and 2B may be rearranged for illustrative purposes. For example, although the SDAP and PDCP layers belong to L2, they are shown above the GTP-U layer, the UDP layer and the IP layer in the protocol stack of the CU-UP of the IAB donor in FIG. 2A.

The signals between each node in an IAB network may include, for example, the following and can be applied to the present disclosure:

- an IAB donor-CU and an IAB donor-DU: an F1AP message;

- an IAB donor-CU and an IAB node: an F1AP message between the CU and the IAB-DU or an RRC message between the CU and the IAB-MT;

- an IAB donor-CU and a UE: an RRC message;

- an access IAB node and a UE: L2-control PDU, such as a MAC control element (CE) or a RLC control PDU; and

- an IAB node and another child or parent IAB node: L2-control PDU, such as a MAC CE, a RLC control PDU, or a BAP control PDU.

As demand for improved cellular coverage and connectivity continues to increase, communications in outdoor and mobility scenarios may face more challenges. In some embodiments of the present disclosure, a mobile wireless network node which acts as a relay between a UE and the 3GPP communication network (e.g., 5G) may be employed to facilitate communications in such scenarios. The mobile wireless network node may provide, for example, an access link to UEs and connected wirelessly (e.g., using NR) through a BS (e.g., donor next-generation radio access network (NG-RAN) ) to the core network. In some examples, such mobile wireless network node may also be referred to as a mobile base station relay or mobile relay. The above descriptions with respect to the wireless network node and the IAB node can be applied to the mobile base station relay. That is, a mobile base station relay can be a mobile IAB node.

In some examples, the mobile base station relay may be mounted on a vehicle. The mobile base station relay may serve UEs that are located inside (onboard) or outside (surrounding) the vehicle, or UEs that enter or leave the vehicle. In the context of the present disclosure, inside or outside of a mobile base station relay may mean inside or outside of a vehicle or other device (s) on which the mobile wireless network node is mounted.

In some examples, the radio link used between a mobile base station relay and the served UEs, as well as between the mobile base station relay and the BS, may be a Uu link (e.g., NR-Uu) , which is different from a UE relay (which uses a PC5-based link to provide, for example, an indirect connection to remote UEs) . In some examples, there may be at least one hop between a UE and a mobile base station relay. In some examples, there may be at least one hop between a mobile base station relay and a BS.

The employment of such mobile wireless network node is advantageous in various aspects and can be applied to various scenarios. For example, in some outdoor environments, the availability of vehicles equipped with mobile base station relays, either following a certain known/predictable itinerary (e.g., buses, trams, etc. ) , or situated in convenient locations (e.g., outside stadiums, hot-spot areas, or emergency sites) , may provide a very opportunistic boost to cellular coverage and capacity when or where needed. Those relays may use, for example, a 5G wireless backhaul toward the macro network, and thus can offer better coverage and connectivity to neighboring UEs. Mobile relays are also very suitable for improving connectivity for users or devices inside a vehicle on which the mobile relay is mounted in different environments, for example, for passengers in buses, cars/taxis, or trains, ad-hoc/professional personnel or equipment. Such mobile wireless network node can also be used for reaching users or devices that would otherwise have no or very poor macro coverage, for example, in the case of first responders dislocated in indoor buildings/areas, using relays placed on their nearby or outside vehicles to get required coverage and connectivity.

The technical benefits of using such a mobile wireless network node (s) further include, among others, the ability to get better macro coverage than a nearby UE, for example, exploiting better radio frequency, antenna and power capabilities. In addition, besides the value for network operators and end users, worthy incentives may be found for other parties as well, for example, for vehicle manufacturers, and vehicle and fleet owners or providers, to install and operate relays in their vehicles.

In the context of the present disclosure, a wireless network node may refer to either a stationary or mobile wireless network node.

In some embodiments, due to, for example, the mobility of a wireless network node (e.g., an IAB node) , the wireless network node may need to migrate (or hand over) from one IAB donor to another IAB donor (i.e., inter-donor migration) .

In some embodiments, a wireless network node may perform a DU migration from an initial (source) IAB donor to a new (target) IAB donor. This migration may be referred to as inter-donor IAB-DU migration. In some embodiments, to execute the handover of the UEs served by a wireless network node (e.g., its DU) , the wireless network node may concurrently support two logical DUs (e.g., DU #1 and DU #2) , which may have F1AP associations with the source IAB donor (e.g., CU of the source IAB donor) and the target IAB donor (e.g., CU of the target IAB donor) , respectively. The UEs connected to the wireless network node may be handed over from a cell (s) of DU #1 (i.e., the source DU of the wireless network node) to a cell (s) of DU #2 (i.e., the target DU of the wireless network node) . After the migration of the DU of the wireless network node, the F1 interface between DU #1 and the source IAB donor can be released.

In the context of the present disclosure, the terms "handover" and "migration" may be used interchangeably. It should be noted that, although embodiments of the present disclosure may be discussed under a specific network architecture (e.g., the IAB architecture) and based on certain specific components (e.g., an IAB donor or an IAB node) , embodiments of the present disclosure are also applicable to other similar network architectures and new service scenarios. It should be noted that although in the context of the present disclosure, both a BS (e.g., an IAB donor) and a network node (e.g., an IAB node) may include a DU, the DU of a BS and the DU of a network node generally function differently.

FIG. 3 illustrates exemplary DU migration procedure 300 in accordance with some embodiments of the present disclosure. In the example of FIG. 3, a wireless network node performs a DU migration from a BS (source BS) to another BS (target BS) while the BS to which the MT of the wireless network node connects does not change. Details described in all of the foregoing embodiments of the present disclosure are applicable for the embodiments shown in FIG. 3.

BS 310A, BS 310B, and BS 310C may function as the IAB donors as described above and may include a CU and at least one DU. Network nodes 320A-320D may function as the IAB nodes as described above, and may include an MT and at least one DU. For example, network node 320D may include one DU before and after DU migration or two DUs during the DU migration.

Referring to FIG. 3, BS 310A may include CU 375 and DU 365, BS 310B may include CU 376 and DU 366, and BS 310C may include CU 377 and DU 367. Network node 320A may be directly connected to BS 310A and may include MT 351 and DU 361. Network node 320B may be directly connected to BS 310B and may include MT 352 and DU 362. Network node 320C may be directly connected to BS 310C and may include MT 353 and DU 363. Network node 320D may include MT 354 and two DUs (DU 364a and DU 364b) , and UE 330 may be connected to network node 320D. Network node 320D may be referred to as an access network node of UE 330.

MT 354 of network node 320D may be anchored at BS 310B (e.g., CU 376) . BS 310B may be referred to as the RRC-terminating BS of network node 320D. Network node 320D may perform a DU migration from BS 310A (i.e., source F1-terminating BS) to BS 310C (i.e., target F1-terminating BS) . MT 354 of network node 320D may retain its connection with BS 310B. In some embodiments, BS 310A may be BS 310B. In some embodiments, BS 310C may be BS 310B.

Before the DU migration, only DU 364a of the network node 320D has an F1 connection to BS 310A (e.g., denoted by signaling flow 340A) . During the DU migration, network node 320D may have two DUs (e.g., DU 364a and DU 364b as shown in FIG. 3) . DU 364a may have an F1 connection to BS 310A and DU 364b may have an F1 connection to BS 310C (e.g., denoted by signaling flow 340B) . And after the DU migration, only DU 364b of the network node 320D has an F1 connection to BS 310C. Both F1 connections are transported via the topology of BS 310B.

Embodiments of the present disclosure provide solutions for facilitating the DU migration of a wireless network node. For example, solutions for facilitating the F1 setup procedure during the DU migration of the wireless network node are provided.

For example, a DU migration of a wireless network node may always be accompanied with handovers for UEs served by the wireless network node. After the DU migration is triggered, the wireless network node may transmit an F1 setup request message to the target BS (e.g., CU of the target BS) . For example, referring to FIG. 3, DU 364b may transmit an F1 setup request message to BS 310C (e.g., CU 377) . This is the first F1AP procedure triggered for the F1-C interface instance after a transport network layer (TNL) association has become operational. At this moment, DU 364b does not have any served UEs. After the F1 setup completion between the wireless network node and the target BS (e.g., CU of the target BS) , the source BS (e.g., BS 310A in FIG. 3) or CU of the source BS (e.g., CU 375 in FIG. 3) may perform a handover for the served UE (s) (e.g., UE 330 served by DU 364a in FIG. 3) from the source BS (e.g., CU of the target BS) to the target BS (e.g., CU of the target BS) . However, the target BS (e.g., CU of the target BS) may refuse the UE handover due to, for example, traffic overload and that the UE (s) loses connection to the source BS because F1 connection between the wireless network node and the source BS will be release after the DU migration. Embodiments of the present disclosure provide an enhancement to the above F1 setup procedure for performing admission control for the DU migration of the wireless network node. For example, in the case of DU migration of a mobile IAB mode, it would be beneficial that the on-board UEs can be handed over together. Such an enhancement can facilitate the handover of the on-board UEs and avoid traffic interruption of on-board UEs.

For example, after the F1 setup between the DU (e.g., DU 364b in FIG. 3) of a wireless network node and the target BS (e.g., CU of the target BS such as CU 377 in FIG. 3) , the wireless network node (e.g., DU 364a in FIG. 3) may transmit the outcome of the F1 setup procedure to the source BS (e.g., CU of the source BS such as CU 375 in FIG. 3) via the F1AP. Based on the outcome, the source BS (e.g., the CU of the source BS) can determine to perform handover for the UEs served by the wireless network node (e.g., UEs served by DU 364a in FIG. 3) . In the case that the DU migration of the wireless network node is triggered by the source BS (e.g., the CU of the source BS) and the F1 setup fails with the target BS (e.g., CU of the target BS) , the source BS (e.g., the CU of the source BS) may only be aware of the failed outcome. However, as the triggering node, it would be beneficial if the source BS (e.g., the CU of the source BS) can be aware of additional information of the failed F1 setup. Embodiments of the present disclosure provide a mechanism to provide additional information of the failed F1 setup that occurred during the DU migration of the wireless network node. Based on such information, the source BS (e.g., the CU of the source BS) can perform a smarter operation for the DU migration of a wireless network node.

More details on the embodiments of the present disclosure will be illustrated in the following text in combination with the appended drawings.

FIG. 4 illustrates a flow chart of exemplary DU migration procedure 400 in accordance with some embodiments of the present disclosure. Details described in all of the foregoing embodiments of the present disclosure are applicable for the embodiments shown in FIG. 4. For example, BSs 410A-410C may function as the IAB donors or the BSs as described above, and network node 420 may function as the IAB nodes or the wireless network nodes as described above.

Referring to FIG. 4, before the DU migration of network node 420, the MT of network node 420 connects to BS 410B and the DU of network node 420 connects to BS 410A. For example, network node 420 (e.g., DU of network node 420) may have an F1 connection with BS 410A (e.g., CU of BS 410A) . Network node 420 (e.g., MT of network node 420) may have an RRC connection with BS 410B (e.g., CU of BS 410B) . BS 410A and BS 410B may be referred to as an F1 terminating BS and an RRC terminating BS, respectively. The CU of BS 410A and the CU of BS 410B may be referred to as an F1 terminating BS-CU and an RRC terminating BS-CU, respectively.

In some embodiments, network node 420 may perform a DU migration from BS 410A to a target BS (e.g., BS 410C) while the MT of network node 420 retains its connection with BS 410B.

For convenience, FIG. 4 shows that the MT and DU of network node 420 connect to two BSs, i.e., BS 410A and BS 410B, before the DU migration and connect to two BSs, BS 410C and BS 410B, after the DU migration. It should be noted that BS 410B may be the same as or different from BS 410A or BS 410C, without departing from the spirit and scope of the disclosure. For example, BS 410B may be the same as BS 410A and the MT and DU of network node 420 may be connected to the same BS before the DU migration, and in this case any coordination between BS 410A and BS 410B is not needed. For example, BS 410C may be the same as BS 410B and the MT and DU of network node 420 may be connected to the same BS after the DU migration, and in this case any coordination between BS 410B and BS 410C is not needed (e.g., operations 421 and 423 can be omitted) .

In some embodiments, BS 410A (e.g., CU of BS 410A) may trigger the DU migration of network node 420. For example, in operation 411 (denoted by a dotted arrow as an option) , BS 410A (e.g., CU of BS 410A) may transmit an F1AP message to indicate network node 420 to trigger a DU migration. For example, network node 420 may include a DU (denoted as DU #A1) having an F1 connection with BS 410A (e.g., CU of BS 410A) . BS 410A (e.g., CU of BS 410A) may transmit the F1AP message to DU #A1.

In some embodiments, the F1AP message may include the ID of BS 410C (e.g., CU of BS 410C) . The ID of BS 410C can be a gNB ID of BS 410C, gNB-CU ID of the CU of BS 410C, an IP address of the CU of BS 410C, or any ID that can identify BS 410C (e.g., CU of BS 410C) .

In some other embodiments, the migration may be triggered by an operation administration and maintenance (OAM) entity or network node 420 itself (e.g., based on a pre-configuration on network node 420) . In these embodiments, operation 411 can be omitted.

During the DU migration of network node 420, network node 420 may have an additional logical DU (denoted as DU #A2) besides DU #A1, wherein network node 420 (e.g., DU #A2) may need to set up an F1 connection to BS 410C (e.g., CU of BS 410C) . In response to the initiating or triggering of the DU migration, network node 420 (e.g., DU #A2) may transmit an F1 setup request message to BS 410C (e.g., CU of BS 410C) in operation 413. For example, the F1 setup request message may be firstly transmitted to BS 410B (e.g., DU of BS 410B) and then delivered to BS 410C (e.g., CU of BS 410C) via IP routing.

In some embodiments, the F1 setup request message may include the ID of BS 410B (e.g., CU of BS 410B) , such that BS 410C (e.g., CU of BS 410C) can trigger a transport migration management (TMM) procedure to the correct RRC-terminating BS (e.g., RRC-terminating CU such as CU of BS 410B) . The ID of BS 410B can be a gNB ID of BS 410B, gNB-CU ID of the CU of BS 410B, an IP address of the CU of BS 410B, or any ID that can identify BS 410B (e.g., CU of BS 410B) .

In some embodiments, the F1 setup request message may include an ID associated with network node 420. The ID associated with network node 420 may be used for BS 410B (e.g., CU of BS 410B) to identify network node 420 in a TMM request message from BS 410C (e.g., CU of BS 410C) . That is, any ID associated with network node 420 that is known by BS 410B (e.g., CU of BS 410B) can be employed. For example, the ID associated with network node 420 may be an ID of the MT of network node 420, an ID of the DU (e.g., DU #A1) of network node 420, or an ID of network node 420. The ID associated with network node 420 can be an XnAP UE ID or a BAP address allocated by BS 410B.

In some embodiments of the present disclosure, information for facilitating admission control during the DU migration of network node 420 may be included in the F1 setup request message. Such information can be used by the target BS (e.g., BS 410C or CU of BS 410C in FIG. 4) of the DU migration to perform admission control for the DU migration.

For example, in some embodiments, the F1 setup request message may include information relating to a UE traffic profile of one or more UEs as served by network node 420. In some examples, the information relating to a UE traffic profile may indicate: (1) the number of UEs connected to network node 420; (2) the number of UEs connected to network node 420 and located inside a vehicle on which network node 420 is mounted; (3) the number of UEs connected to network node 420 and located outside the vehicle on which network node 420 is mounted; (4) a volume of downlink traffic for all UEs connected to network node 420; (5) a volume of uplink traffic for all UEs connected to network node 420; (6) a volume of downlink traffic for all UEs connected to network node 420 and located inside the vehicle on which network node 420 is mounted; (7) a volume of uplink traffic for all UEs connected to network node 420 and located inside the vehicle on which network node 420 is mounted; (8) a volume of downlink traffic for all UEs connected to network node 420 and located outside the vehicle on which network node 420 is mounted; (9) a volume of uplink traffic for all UEs connected to network node 420 and located outside the vehicle on which network node 420 is mounted; (10) a bit rate for downlink traffic; (11) a bit rate for uplink traffic; or any combination thereof. In some embodiments, the bit rate may include a guaranteed flow bit rate (GFBR) or a maximum flow bit rate (MFBR) .

Among the above information (1) - (11) , information (2) , (3) and (6) - (9) can be applied to mobile network node (i.e., mobile IAB node) and the remaining can be applied to both stationary and mobile network nodes.

In response to receiving the F1 setup request message, BS 410C (e.g., CU of BS 410C) may determine to accept or reject the DU migration of network node 420. For example, based on the information relating to the UE traffic profile in the F1 setup request message, BS 410C (e.g., CU of BS 410C) may determine to accept or reject the DU migration of network node 420, and may transmit an F1 setup response message or an F1 setup failure message to network node 420.

For example, in the case of F1 setup success, BS 410C (e.g., CU of BS 410C) may transmit an F1 setup response message to network node 420 (e.g., DU #A2) in operation 415. The F1 setup response message may include a list of cells (denoted as list #A) that BS 410C (e.g., CU of BS 410C) requests network node 420 (e.g., DU #A2) to activate. For example, the F1 setup response message may be firstly delivered to BS 410B (e.g., DU of BS 410B) via IP routing and then transmitted to network node 420 via BAP routing.

In some embodiments of the present disclosure, the F1 setup response message may further indicate: the number of UEs allowed to be handed over from BS 410A to BS 410C, a volume of downlink traffic allowed, a volume of uplink traffic allowed, or any combination thereof.

In some embodiments, after the F1 setup procedure between DU #A2 and BS 410C (e.g., CU of BS 410C) , network node 420 (e.g., DU #A1) may, in operation 417, indicate to BS 410A (e.g., CU of BS 410A) the outcome of the F1 setup procedure to BS 410C (e.g., CU of BS 410C) . For example, in operation 417, network node 420 (e.g., DU #A1) may transmit an F1 setup outcome notification message to BS 410A (e.g., CU of BS 410A) . In some embodiments, the F1 setup outcome notification message may be based on the F1 setup response message in the case of F1 setup success (or an F1 setup failure message in the case of F1 setup failure) .

For example, in some embodiments, the F1 setup outcome notification message may indicate whether the F1 setup is successful or has failed. For example, the F1 setup outcome notification message may include an information element (denoted as "F1 Setup Outcome" IE) indicating the "success" or "failure" of the F1 setup between network node 420 (e.g., DU #A2) and BS 410C (e.g., CU of BS 410C) .

For example, in some embodiments, the F1 setup outcome notification message may inform BS 410A (e.g., CU of BS 410A) of the list of cells that BS 410C (e.g., CU of BS 410C) requests network node 420 (e.g., DU #A2) to activate if the outcome of the F1 setup is successful. For example, the F1 setup outcome notification message may include list #Ain the F1 setup response message.

For example, in some embodiments, the F1 setup outcome notification message may indicate: the number of UEs allowed to be handed over from BS 410A to BS 410C, a volume of downlink traffic allowed, a volume of uplink traffic allowed, or any combination thereof. As described with respect to operation 415, the F1 setup response message may indicate the above information.

In some embodiments, in response to receiving the F1 setup outcome notification message, BS 410A (e.g., CU of BS 410A) may, in operation 419, trigger a handover (s) of UE (s) served by network node 420 (e.g., DU #A1) from BS 410A (e.g., CU of BS 410A) to BS 410C (e.g., CU of BS 410C) . The UE handover may be based on information indicated in the F1 setup outcome notification message, for example, the number of UEs allowed to be handed over from BS 410A to BS 410C, a volume of downlink traffic allowed, or a volume of uplink traffic allowed.

In some embodiments, BS 410C (e.g., CU of BS 410C) may trigger a TMM procedure (e.g., IAB TMM procedure) to exchange information between BS 410C (e.g., CU of BS 410C) and BS 410B (e.g., CU of BS 410B) of network node 420 and to manage the migration of network node 420 and descendant node traffic between the topologies managed by the two BSs (e.g., the two CUs) .

For example, in operation 421, BS 410C (e.g., CU of BS 410C) may transmit a TMM request message to BS 410B (e.g., CU of BS 410B) . In some embodiments, the TMM request message may include the ID associated with network node 420 as described above with respect to operation 413. In some embodiments, based on the ID associated with network node 420 in the TMM request message, BS 410B (e.g., CU of BS 410B) can recognize network node 420.

In operation 423, BS 410B (e.g., CU of BS 410B) may transmit a TMM response message to BS 410C (e.g., CU of BS 410C) as a response to the TMM request message.

In some embodiments, after the TMM procedure, BS 410B (e.g., CU of BS 410B) may update the BAP configuration and the F1 traffic between network node 420 and BS 410C (e.g., CU of BS 410C) can be transported via the BH links under BS 410B (e.g., CU of BS 410B) .

It should be appreciated by persons skilled in the art that the sequence of the operations in exemplary procedure 400 may be changed and some of the operations in exemplary procedure 400 may be eliminated or modified, without departing from the spirit and scope of the disclosure. For example, operations 417 and 419 may be performed in parallel with or after operations 421 and 423. For example, operation 421 may be performed in parallel with or before operation 415.

FIG. 5 illustrates a flow chart of exemplary DU migration procedure 500 in accordance with some embodiments of the present disclosure. Details described in all of the foregoing embodiments of the present disclosure are applicable for the embodiments shown in FIG. 5. For example, BSs 510A-510C may function as the IAB donors or the BSs as described above, and network node 520 may function as the IAB nodes or the wireless network nodes as described above.

Referring to FIG. 5, before the DU migration of network node 520, the MT of network node 520 connects to BS 510B and the DU of network node 520 connects to BS 510A. For example, network node 520 (e.g., DU of network node 520) may have an F1 connection with BS 510A (e.g., CU of BS 510A) . Network node 520 (e.g., MT of network node 520) may have an RRC connection with BS 510B (e.g., CU of BS 510B) . BS 510A and BS 510B may be referred to as an F1 terminating BS and an RRC terminating BS, respectively. The CU of BS 510A and the CU of BS 510B may be referred to as an F1 terminating BS-CU and an RRC terminating BS-CU, respectively.

In some embodiments, network node 520 may perform a DU migration from BS 510A to a target BS (e.g., BS 510C) while the MT of network node 520 retains its connection with BS 510B. It should be noted that BS 510B may be the same as or different from BS 510A or BS 510C, without departing from the spirit and scope of the disclosure.

In some embodiments, BS 510A (e.g., CU of BS 510A) may trigger the DU migration of network node 520. For example, in operation 511, BS 510A (e.g., CU of BS 510A) may transmit an F1AP message to indicate network node 520 to trigger a DU migration. For example, network node 520 may include a DU (denoted as DU #B1) having an F1 connection with BS 510A (e.g., CU of BS 510A) . BS 510A (e.g., CU of BS 510A) may transmit the F1AP message to DU #B1.

In some embodiments, the F1AP message may include the ID of BS 510C (e.g., CU of BS 510C) . The ID of BS 510C can be a gNB ID of BS 510C, gNB-CU ID of the CU of BS 510C, an IP address of the CU of BS 510C, or any ID that can identify BS 510C (e.g., CU of BS 510C) .

During the DU migration of network node 520, network node 520 may have an additional logical DU (denoted as DU #B2) besides DU #B1, wherein network node 520 (e.g., DU #B2) may need to set up an F1 connection to BS 510C (e.g., CU of BS 510C) . In response to the initiating or triggering of the DU migration, network node 520 (e.g., DU #B2) may transmit an F1 setup request message to BS 510C (e.g., CU of BS 510C) in operation 513. For example, the F1 setup request message may be firstly transmitted to BS 510B (e.g., DU of BS 510B) and then delivered to BS 510C (e.g., CU of BS 510C) via IP routing.

In some embodiments, the F1 setup request message may include the ID of BS 510B (e.g., CU of BS 510B) , such that BS 510C (e.g., CU of BS 510C) can trigger a transport migration management (TMM) procedure to the correct RRC-terminating BS (e.g., RRC-terminating CU such as CU of BS 510B) . The ID of BS 510B can be a gNB ID of BS 510B, gNB-CU ID of the CU of BS 510B, an IP address of the CU of BS 510B, or any ID that can identify BS 510B (e.g., CU of BS 510B) .

In some embodiments, the F1 setup request message may include an ID associated with network node 520. The ID associated with network node 520 may be used for BS 510B (e.g., CU of BS 510B) to identify network node 520 in a TMM request message from BS 510C (e.g., CU of BS 510C) . That is, any ID associated with network node 520 that is known by BS 510B (e.g., CU of BS 510B) can be employed. For example, the ID associated with network node 520 may be an ID of the MT of network node 520, an ID of the DU (e.g., DU #B1) of network node 520, or an ID of network node 520. The ID associated with network node 520 can be an XnAP UE ID or a BAP address allocated by BS 510B.

In some embodiments of the present disclosure, information for facilitating admission control during the DU migration of network node 520 may be included in the F1 setup request message. Such information can be used by the target BS (e.g., BS 510C or CU of BS 510C in FIG. 5) of the DU migration to perform admission control for the DU migration. For example, in some embodiments, the F1 setup request message may include information relating to a UE traffic profile of one or more UEs as served by network node 520. The information relating to a UE traffic profile as described above with respect to FIG. 4 may apply here.

In some other embodiments of the present disclosure, the F1 setup request message may not include the above information for facilitating admission control.

In response to receiving the F1 setup request message, BS 510C (e.g., CU of BS 510C) may determine to accept or reject the DU migration of network node 520.

In some embodiments, based on the information relating to the UE traffic profile (if included) in the F1 setup request message, BS 510C (e.g., CU of BS 510C) may determine to accept or reject the DU migration of network node 520, and may transmit an F1 setup response message or an F1 setup failure message to network node 520.

In some embodiments, BS 510C (e.g., CU of BS 510C) may determine to reject the DU migration of network node 520 and transmit an F1 setup failure message to network node 520 (e.g., DU #B2) in operation 515.

In some embodiments, the F1 setup failure message may indicate a cause value (hereinafter, info #A1) of the F1 setup failure. For example, the F1 setup failure message may include a "cause" IE indicating the cause of the F1 setup failure. For example, the value of the “cause” IE may be “No Radio Resources Available” or “gNB-CU Cell Capacity Exceeded” or any other reasons that BS 510C fails to accept the F1 setup request. In some embodiments, the F1 setup failure message may indicate a waiting time (hereinafter, info #A2) before initiating or reinitiating another F1 setup procedure or another DU migration procedure to BS 510C (e.g., CU of BS 510C) . For example, the F1 setup failure message may include a "Time To Wait" IE indicating a waiting time. Network node 520 (e.g., DU #B2) may wait at least for the indicated waiting time before initiating or reinitiating another F1 setup towards BS 510C (e.g., CU of BS 510C) . That is, the indicated waiting time is the minimum waiting time before initiating or reinitiating another F1 setup towards BS 510C (e.g., CU of BS 510C) .

In some embodiments, after the F1 setup procedure between DU #B2 and BS 510C (e.g., CU of BS 510C) , network node 520 (e.g., DU #B1) may, in operation 517, indicate to BS 510A (e.g., CU of BS 510A) the outcome of the F1 setup procedure to BS 510C (e.g., CU of BS 510C) . For example, in operation 517, network node 520 (e.g., DU #B1) may transmit an F1 setup outcome notification message to BS 510A (e.g., CU of BS 510A) . In some embodiments, the F1 setup outcome notification message may be based on the F1 setup failure message in the case of F1 setup failure (or an F1 setup response message in the case of F1 setup success) .

For example, in some embodiments, the F1 setup outcome notification message may indicate whether the F1 setup is successful or has failed. For example, the F1 setup outcome notification message may include an information element (denoted as "F1 Setup Outcome" IE) indicating the "success" or "failure" of the F1 setup between network node 520 (e.g., DU #B2) and BS 510C (e.g., CU of BS 510C) . In the case that the F1 setup failure message is received, the "F1 Setup Outcome" IE may be set to "failure. "

As mentioned before, if the source BS which triggers the DU migration of a wireless network node can be aware of information of a failed F1 setup, it can perform a smarter DU migration of the wireless network node. To gain this end, in some embodiments, the F1 setup outcome notification message transmitted in operation 517 may include additional information of the failed F1 setup that occurred during the DU migration of network node 520. For example, the F1 setup outcome notification message may indicate a cause value of the F1 setup failure; a waiting time before reinitiating another F1 setup procedure or another DU migration procedure to BS 510C (e.g., CU of BS 510C) , or both. The above additional information may be based on the F1 setup failure message, for example, info #A1 and info #A2.

In some examples, the F1 setup outcome notification message may include a "cause" IE. The value of the "cause" IE may be based on info #A1. For example, network node 520 can copy info #A1 in the F1 setup failure message and paste it in the F1 setup outcome notification message. In some examples, the F1 setup outcome notification message may include a "Time To Wait" IE. The value of the "Time To Wait" IE may be based on info #A2. For example, network node 520 can copy info #A2 in the F1 setup failure message and paste it in the F1 setup outcome notification message.

In some examples, when the "F1 Setup Outcome" IE is included in the F1 setup outcome notification message and is set to "failure" (or put another way, the F1 setup outcome notification message includes an indication indicating the failure of the F1 setup) , network node 520 (e.g., DU #B1) may include the cause value of the F1 setup (e.g., a "cause" IE) , the waiting time (e.g., "Time To Wait" IE) or both in the F1 setup outcome notification message. In some examples, the "cause" IE and the "F1 Setup Outcome" IE may be merged into one IE (or a single indication in the F1 setup outcome notification message) , which can indicate F1 Setup success and various failure causes for an F1 setup.

In some embodiments, BS 510A (e.g., CU of BS 510A) may, in operation 519, act according to the F1 setup outcome notification message. For example, BS 510A (e.g., CU of BS 510A) may select another target BS (e.g., BS-CU) for network node 520. For example, BS 510A (e.g., CU of BS 510A) may trigger another F1 setup procedure to the same target BS (i.e., BS 510C or CU of BS 510C) after a period of time. The time period may be based on the "Time To Wait" IE in the F1 setup outcome notification message.

It should be appreciated by persons skilled in the art that the sequence of the operations in exemplary procedure 500 may be changed and some of the operations in exemplary procedure 500 may be eliminated or modified, without departing from the spirit and scope of the disclosure.

FIG. 6 illustrates a flow chart of exemplary method 600 for wireless communications in accordance with some embodiments of the present disclosure. Details described in all of the foregoing embodiments of the present disclosure are applicable for the embodiments shown in FIG. 6. In some examples, method 600 may be performed by a NE such as a network node, a wireless network node or an IAB node. In some embodiments, the NE may execute a set of instructions to control the functional elements of the network node to perform the described functions or operations. For the sake of simplicity, the operations in method 600 are described as follows with respect to a wireless network node.

At 611, a wireless network node may transmit an F1 setup request message to a first BS, the F1 setup request message being for performing a DU migration of the wireless network node from a second BS to the first BS. In some embodiments, the F1 setup request message may include information relating to a UE traffic profile of one or more UEs as served by the wireless network node.

In some embodiments, the information relating to the UE traffic profile may indicate: the number of UEs connected to the wireless network node; the number of UEs connected to the wireless network node and located inside a vehicle on which the wireless network node is mounted; the number of UEs connected to the wireless network node and located outside the vehicle on which the wireless network node is mounted; a volume of downlink traffic for all UEs connected to the wireless network node; a volume of uplink traffic for all UEs connected to the wireless network node; a volume of downlink traffic for all UEs connected to the wireless network node and located inside the vehicle on which the wireless network node is mounted; a volume of uplink traffic for all UEs connected to the wireless network node and located inside the vehicle on which the wireless network node is mounted; a volume of downlink traffic for all UEs connected to the wireless network node and located outside the vehicle on which the wireless network node is mounted; a volume of uplink traffic for all UEs connected to the wireless network node and located outside the vehicle on which the wireless network node is mounted; a bit rate for downlink traffic; a bit rate for uplink traffic; or any combination thereof.

In some embodiments, the bit rate may include a GFBR or an MFBR. For example, the information relating to the UE traffic profile may indicate a GFBR of the downlink traffic, a GFBR of the uplink traffic, or both. For example, the information relating to the UE traffic profile may indicate an MFBR of the downlink traffic, an MFBR of the uplink traffic, or both.

At 613, in response to transmitting the F1 setup request message, the wireless network node may receive a response message to the F1 setup request message from the first BS.

In some embodiments, the response message may be an F1 setup response message which may indicate: the number of UEs allowed to be handed over from the second BS to the first BS; a volume of downlink traffic allowed; a volume of uplink traffic allowed; or any combination thereof. In some embodiments, the wireless network node may transmit an F1 setup outcome notification message to the second BS based on the F1 setup response message. In some embodiments, the F1 setup outcome notification message may indicate: the number of UEs allowed to be handed over from the second BS to the first BS; a volume of downlink traffic allowed; a volume of uplink traffic allowed; or any combination thereof.

In some embodiments, the response message may be an F1 setup failure message which may indicate: a cause value of the F1 setup failure; or a waiting time before reinitiating another F1 setup procedure or another DU migration procedure to the first BS; or both. In some embodiments, the wireless network node may transmit an F1 setup outcome notification message to the second BS based on the F1 setup failure message. In some embodiments, the F1 setup outcome notification message may indicate: a cause value of the F1 setup failure; or a waiting time before reinitiating another F1 setup procedure or another DU migration procedure to the first BS;or both.

It should be appreciated by persons skilled in the art that the sequence of the operations in exemplary method 600 may be changed and some of the operations in exemplary method 600 may be eliminated or modified, without departing from the spirit and scope of the disclosure.

FIG. 7 illustrates a flow chart of exemplary method 700 for wireless communications in accordance with some embodiments of the present disclosure. Details described in all of the foregoing embodiments of the present disclosure are applicable for the embodiments shown in FIG. 7. In some examples, method 700 may be performed by a NE such as a BS or an IAB donor. In some embodiments, the NE may execute a set of instructions to control the functional elements of the network node to perform the described functions or operations. For the sake of simplicity, the operations in method 700 are described as follows with respect to a BS.

At 711, a first BS may receive an F1 setup request message from a wireless network node, the F1 setup request message being for performing a DU migration of the wireless network node from a second BS to the first BS. In some embodiments, the F1 setup request message may include information relating to a UE traffic profile of one or more UEs as served by the wireless network node.

At 713, the first BS may transmit, to the wireless network node, a response message to the F1 setup request message, in response to receiving the F1 setup request message.

In some embodiments, the response message may be an F1 setup response message which may indicate: the number of UEs allowed to be handed over from the second BS to the first BS; a volume of downlink traffic allowed; a volume of uplink traffic allowed; or any combination thereof.

It should be appreciated by persons skilled in the art that the sequence of the operations in exemplary method 700 may be changed and some of the operations in exemplary method 700 may be eliminated or modified, without departing from the spirit and scope of the disclosure.

FIG. 7A illustrates a flow chart of exemplary method 700A for wireless communications in accordance with some embodiments of the present disclosure. Details described in all of the foregoing embodiments of the present disclosure are applicable for the embodiments shown in FIG. 7A. In some examples, method 700A may be performed by a NE such as a BS or an IAB donor. In some embodiments, the NE may execute a set of instructions to control the functional elements of the network node to perform the described functions or operations. For the sake of simplicity, the operations in method 700A are described as follows with respect to a BS.

At 731, a second BS may initiate a DU migration of a wireless network node from the second BS to a first BS. At 733, the second BS may receive an F1 setup outcome notification message from the wireless network node, wherein the F1 setup outcome notification message indicates: a cause value of an F1 setup failure associated with the DU migration of the wireless network node, or a waiting time before reinitiating another F1 setup procedure or another DU migration procedure to the first BS.

It should be appreciated by persons skilled in the art that the sequence of the operations in exemplary method 700A may be changed and some of the operations in exemplary method 700A may be eliminated or modified, without departing from the spirit and scope of the disclosure.

FIG. 8 illustrates an example of an NE 800 in accordance with aspects of the present disclosure. NE 800 may be a network node, a wireless network node, an IAB node, a BS or an IAB donor. The NE 800 may include a processor 802, a memory 804, a controller 806, and a transceiver 808. The processor 802, the memory 804, the controller 806, or the transceiver 808, or various combinations thereof or various components thereof may be examples of means for performing various aspects of the present disclosure as described herein. These components may be coupled (e.g., operatively, communicatively, functionally, electronically, electrically) via one or more interfaces.

The processor 802, the memory 804, the controller 806, or the transceiver 808, or various combinations or components thereof may be implemented in hardware (e.g., circuitry) . The hardware may include a processor, a DSP, an ASIC, or other programmable logic device, or any combination thereof configured as or otherwise supporting a means for performing the functions described in the present disclosure.

The processor 802 may include an intelligent hardware device (e.g., a general-purpose processor, a DSP, a CPU, an ASIC, an FPGA, or any combination thereof) . In some implementations, the processor 802 may be configured to operate the memory 804. In some other implementations, the memory 804 may be integrated into the processor 802. The processor 802 may be configured to execute computer-readable instructions stored in the memory 804 to cause the NE 800 to perform various functions of the present disclosure.

The memory 804 may include volatile or non-volatile memory. The memory 804 may store computer-readable, computer-executable code including instructions when executed by the processor 802 cause the NE 800 to perform various functions described herein. The code may be stored in a non-transitory computer-readable medium such as the memory 804 or another type of memory. Computer-readable media includes both non-transitory computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A non-transitory storage medium may be any available medium that may be accessed by a general-purpose or special-purpose computer.

In some implementations, the processor 802 and the memory 804 coupled with the processor 802 may be configured to cause the NE 800 to perform one or more of the functions described herein (e.g., executing, by the processor 802, instructions stored in the memory 804) . For example, the processor 802 may support wireless communication at the NE 800 in accordance with examples as disclosed herein.

For example, the NE 800 may be configured to support means for performing the operations as described with respect to FIG. 6. For example, the NE 800 may be configured to support: a means for transmitting an F1 setup request message to a first BS, the F1 setup request message being for performing a DU migration of the NE 800 from a second BS to the first BS, and wherein the F1 setup request message may include information relating to a UE traffic profile of one or more UEs as served by the NE 800; and a means for receiving a response message to the F1 setup request message from the first BS in response to transmitting the F1 setup request message.

For example, the NE 800 may be configured to support means for performing the operations as described with respect to FIG. 7. For example, the NE 800 may be configured to support: a means for receiving an F1 setup request message from a wireless network node, the F1 setup request message being for performing a DU migration of the wireless network node from a second BS to the NE 800, and wherein the F1 setup request message may include information relating to a UE traffic profile of one or more UEs as served by the wireless network node; and a means for transmitting, to the wireless network node, a response message to the F1 setup request message, in response to receiving the F1 setup request message.

For example, the NE 800 may be configured to support means for performing the operations as described with respect to FIG. 7A. For example, the NE 800 may be configured to support: a means for initiating a DU migration of a wireless network node from the NE 800 to a first BS; and a means for receiving an F1 setup outcome notification message from the wireless network node, wherein the F1 setup outcome notification message may indicate: a cause value of an F1 setup failure associated with the DU migration of the wireless network node, or a waiting time before reinitiating another F1 setup procedure or another DU migration procedure to the first BS, or both.

The controller 806 may manage input and output signals for the NE 800. The controller 806 may also manage peripherals not integrated into the NE 800. In some implementations, the controller 806 may utilize an operating system such as or other operating systems. In some implementations, the controller 806 may be implemented as part of the processor 802.

In some implementations, the NE 800 may include at least one transceiver 808. In some other implementations, the NE 800 may have more than one transceiver 808. The transceiver 808 may represent a wireless transceiver. The transceiver 808 may include one or more receiver chains 810, one or more transmitter chains 812, or a combination thereof.

A receiver chain 810 may be configured to receive signals (e.g., control information, data, or packets) over a wireless medium. For example, the receiver chain 810 may include one or more antennas for receive the signal over the air or wireless medium. The receiver chain 810 may include at least one amplifier (e.g., an LNA) configured to amplify the received signal. The receiver chain 810 may include at least one demodulator configured to demodulate the receive signal and obtain the transmitted data by reversing the modulation technique applied during transmission of the signal. The receiver chain 810 may include at least one decoder for decoding the processing the demodulated signal to receive the transmitted data.

A transmitter chain 812 may be configured to generate and transmit signals (e.g., control information, data, or packets) . The transmitter chain 812 may include at least one modulator for modulating data onto a carrier signal, preparing the signal for transmission over a wireless medium. The at least one modulator may be configured to support one or more techniques such as AM, FM, or digital modulation schemes like PSK or QAM. The transmitter chain 812 may also include at least one power amplifier configured to amplify the modulated signal to an appropriate power level suitable for transmission over the wireless medium. The transmitter chain 812 may also include one or more antennas for transmitting the amplified signal into the air or wireless medium.

It should be appreciated by persons skilled in the art that the components in exemplary NE 800 may be changed, for example, some of the components in exemplary NE 800 may be omitted or modified or a new component (s) may be added to exemplary NE 800, without departing from the spirit and scope of the disclosure. For example, in some embodiments, the NE 800 may not include the controller 806.

FIG. 9 illustrates an example of a processor 900 in accordance with aspects of the present disclosure. The processor 900 may be an example of a processor configured to perform various operations in accordance with examples as described herein. The processor 900 may include a controller 902 configured to perform various operations in accordance with examples as described herein. The processor 900 may optionally include at least one memory 904, which may be, for example, an L1/L2/L3 cache. Additionally, or alternatively, the processor 900 may optionally include one or more arithmetic-logic units (ALUs) 906. One or more of these components may be in electronic communication or otherwise coupled (e.g., operatively, communicatively, functionally, electronically, electrically) via one or more interfaces (e.g., buses) .

The processor 900 may be a processor chipset and include a protocol stack (e.g., a software stack) executed by the processor chipset to perform various operations (e.g., receiving, obtaining, retrieving, transmitting, outputting, forwarding, storing, determining, identifying, accessing, writing, reading) in accordance with examples as described herein. The processor chipset may include one or more cores, one or more caches (e.g., memory local to or included in the processor chipset (e.g., the processor 900) or other memory (e.g., random access memory (RAM) , read-only memory (ROM) , dynamic RAM (DRAM) , synchronous dynamic RAM (SDRAM) , static RAM (SRAM) , ferroelectric RAM (FeRAM) , magnetic RAM (MRAM) , resistive RAM (RRAM) , flash memory, phase change memory (PCM) , and others) .

The controller 902 may be configured to manage and coordinate various operations (e.g., signaling, receiving, obtaining, retrieving, transmitting, outputting, forwarding, storing, determining, identifying, accessing, writing, reading) of the processor 900 to cause the processor 900 to support various operations in accordance with examples as described herein. For example, the controller 902 may operate as a control unit of the processor 900, generating control signals that manage the operation of various components of the processor 900. These control signals include enabling or disabling functional units, selecting data paths, initiating memory access, and coordinating timing of operations.

The controller 902 may be configured to fetch (e.g., obtain, retrieve, receive) instructions from the memory 904 and determine a subsequent instruction (s) to be executed to cause the processor 900 to support various operations in accordance with examples as described herein. The controller 902 may be configured to track memory address of instructions associated with the memory 904. The controller 902 may be configured to decode instructions to determine the operation to be performed and the operands involved. For example, the controller 902 may be configured to interpret the instruction and determine control signals to be output to other components of the processor 900 to cause the processor 900 to support various operations in accordance with examples as described herein. Additionally, or alternatively, the controller 902 may be configured to manage flow of data within the processor 900. The controller 902 may be configured to control transfer of data between registers, ALUs, and other functional units of the processor 900.

The memory 904 may include one or more caches (e.g., memory local to or included in the processor 900 or other memory, such RAM, ROM, DRAM, SDRAM, SRAM, MRAM, flash memory, etc. In some implementations, the memory 904 may reside within or on a processor chipset (e.g., local to the processor 900) . In some other implementations, the memory 904 may reside external to the processor chipset (e.g., remote to the processor 900) .

The memory 904 may store computer-readable, computer-executable code including instructions that, when executed by the processor 900, cause the processor 900 to perform various functions described herein. The code may be stored in a non-transitory computer-readable medium such as system memory or another type of memory. The controller 902 and/or the processor 900 may be configured to execute computer-readable instructions stored in the memory 904 to cause the processor 900 to perform various functions. For example, the processor 900 and/or the controller 902 may be coupled with or to the memory 904, the processor 900, the controller 902, and the memory 904 may be configured to perform various functions described herein. In some examples, the processor 900 may include multiple processors and the memory 904 may include multiple memories. One or more of the multiple processors may be coupled with one or more of the multiple memories, which may, individually or collectively, be configured to perform various functions herein.

The one or more ALUs 906 may be configured to support various operations in accordance with examples as described herein. In some implementations, the one or more ALUs 906 may reside within or on a processor chipset (e.g., the processor 900) . In some other implementations, the one or more ALUs 906 may reside external to the processor chipset (e.g., the processor 900) . One or more ALUs 906 may perform one or more computations such as addition, subtraction, multiplication, and division on data. For example, one or more ALUs 906 may receive input operands and an operation code, which determines an operation to be executed. One or more ALUs 906 be configured with a variety of logical and arithmetic circuits, including adders, subtractors, shifters, and logic gates, to process and manipulate the data according to the operation. Additionally, or alternatively, the one or more ALUs 906 may support logical operations such as AND, OR, exclusive-OR (XOR) , not-OR (NOR) , and not-AND (NAND) , enabling the one or more ALUs 906 to handle conditional operations, comparisons, and bitwise operations.

The processor 900 may support wireless communication in accordance with examples as disclosed herein.

For example, the processor 900 may be configured to support means for performing the operations as described with respect to FIG. 6. For example, the processor 900 may be configured to or operable to support: a means for transmitting an F1 setup request message to a first BS, the F1 setup request message being for performing a DU migration of a wireless network node from a second BS to the first BS, and wherein the F1 setup request message may include information relating to a UE traffic profile of one or more UEs as served by the wireless network node; and a means for receiving a response message to the F1 setup request message from the first BS in response to transmitting the F1 setup request message.

For example, the processor 900 may be configured to support means for performing the operations as described with respect to FIG. 7. For example, the processor 900 may be configured to or operable to support: a means for receiving an F1 setup request message from a wireless network node, the F1 setup request message being for performing a DU migration of the wireless network node from a second BS to a first BS, and wherein the F1 setup request message may include information relating to a UE traffic profile of one or more UEs as served by the wireless network node; and a means for transmitting, to the wireless network node, a response message to the F1 setup request message, in response to receiving the F1 setup request message.

For example, the processor 900 may be configured to support: a means for initiating a DU migration of a wireless network node from a second BS to a first BS; and a means for receiving an F1 setup outcome notification message from the wireless network node, wherein the F1 setup outcome notification message may indicate: a cause value of an F1 setup failure associated with the DU migration of the wireless network node, or a waiting time before reinitiating another F1 setup procedure or another DU migration procedure to the first BS, or both.

It should be appreciated by persons skilled in the art that the components in exemplary processor 900 may be changed, for example, some of the components in exemplary processor 900 may be omitted or modified or a new component (s) may be added to exemplary processor 900, without departing from the spirit and scope of the disclosure. For example, in some embodiments, the processor 900 may not include the ALUs 906.

Those having ordinary skill in the art would understand that the operations or steps of the methods described in connection with the aspects disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. Additionally, in some aspects, the operations or steps of the methods may reside as one or any combination or set of codes and/or instructions on a non-transitory computer-readable medium, which may be incorporated into a computer program product.

While this disclosure has been described with specific embodiments thereof, it is evident that many alternatives, modifications, and variations may be apparent to those skilled in the art. The disclosure is not limited to the examples and designs described herein but is to be accorded with the broadest scope consistent with the principles and novel features disclosed herein. For example, various components of the embodiments may be interchanged, added, or substituted in other embodiments. Also, all of the elements of each figure are not necessary for the operation of the disclosed embodiments. For example, one of ordinary skill in the art of the disclosed embodiments would be enabled to make and use the teachings of the disclosure by simply employing the elements of the independent claims. Accordingly, embodiments of the disclosure as set forth herein are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the disclosure.

In this document, this document, the terms "includes, " "including, " or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "a, " "an, " or the like does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that includes the element. Also, the term "another" is defined as at least a second or more. The term "having" or the like, as used herein, is defined as "including. " Expressions such as "A and/or B" or "at least one of A and B" may include any and all combinations of words enumerated along with the expression. For instance, the expression "A and/or B" or "at least one of A and B" may include A, B, or both A and B. The wording "the first, " "the second" or the like is only used to clearly illustrate the embodiments of the present disclosure, but is not used to limit the substance of the present disclosure.

Claims

A wireless network node, comprising:

at least one memory; and

at least one processor coupled with the at least one memory and configured to cause the wireless network node to:

transmit an F1 setup request message to a first base station (BS) , the F1 setup request message being for performing a distributed unit (DU) migration of the wireless network node from a second BS to the first BS, and wherein the F1 setup request message comprises information relating to a user equipment (UE) traffic profile of one or more UEs as served by the wireless network node; and

in response to transmitting the F1 setup request message, receive a response message to the F1 setup request message from the first BS.
The wireless network node of Claim 1, wherein the information relating to the UE traffic profile indicates:

the number of UEs connected to the wireless network node;

the number of UEs connected to the wireless network node and located inside a vehicle on which the wireless network node is mounted;

the number of UEs connected to the wireless network node and located outside the vehicle on which the wireless network node is mounted;

a volume of downlink traffic for all UEs connected to the wireless network node;

a volume of uplink traffic for all UEs connected to the wireless network node;

a volume of downlink traffic for all UEs connected to the wireless network node and located inside the vehicle on which the wireless network node is mounted;

a volume of uplink traffic for all UEs connected to the wireless network node and located inside the vehicle on which the wireless network node is mounted;

a volume of downlink traffic for all UEs connected to the wireless network node and located outside the vehicle on which the wireless network node is mounted;

a volume of uplink traffic for all UEs connected to the wireless network node and located outside the vehicle on which the wireless network node is mounted;

a bit rate for downlink traffic;

a bit rate for uplink traffic; or

any combination thereof.
The wireless network node of Claim 2, wherein the bit rate comprises a guaranteed flow bit rate (GFBR) or a maximum flow bit rate (MFBR) .
The wireless network node of any of Claims 1-3, wherein the response message is an F1 setup response message which indicates:

the number of UEs allowed to be handed over from the second BS to the first BS;

a volume of downlink traffic allowed; or

a volume of uplink traffic allowed.
The wireless network node of Claim 4, wherein the at least one processor is further configured to cause the wireless network node to transmit an F1 setup outcome notification message to the second BS based on the F1 setup response message.
The wireless network node of Claim 5, wherein the F1 setup outcome notification message indicates:

the number of UEs allowed to be handed over from the second BS to the first BS;

a volume of downlink traffic allowed; or

a volume of uplink traffic allowed.
The wireless network node of any of Claims 1-3, wherein the response message is an F1 setup failure message which indicates:

a cause value of the F1 setup failure; or

a waiting time before reinitiating another F1 setup procedure or another DU migration procedure to the first BS.
The wireless network node of Claim 7, wherein the at least one processor is further configured to cause the wireless network node to transmit an F1 setup outcome notification message to the second BS based on the F1 setup failure message.
The wireless network node of Claim 8, wherein the F1 setup outcome notification message indicates:

a cause value of the F1 setup failure; or

a waiting time before reinitiating another F1 setup procedure or another DU migration procedure to the first BS.
A first base station (BS) , comprising:

at least one memory; and

at least one processor coupled with the at least one memory and configured to cause the first BS to:

receive an F1 setup request message from a wireless network node, the F1 setup request message being for performing a distributed unit (DU) migration of the wireless network node from a second BS to the first BS, and wherein the F1 setup request message comprises information relating to a user equipment (UE) traffic profile of one or more UEs as served by the wireless network node; and

transmit, to the wireless network node, a response message to the F1 setup request message, in response to receiving the F1 setup request message.
The first BS of Claim 10, wherein the information relating to the UE traffic profile indicates:

the number of UEs connected to the wireless network node;

the number of UEs connected to the wireless network node and located inside a vehicle on which the wireless network node is mounted;

the number of UEs connected to the wireless network node and located outside the vehicle on which the wireless network node is mounted;

a volume of downlink traffic for all UEs connected to the wireless network node;

a volume of uplink traffic for all UEs connected to the wireless network node;

a volume of downlink traffic for all UEs connected to the wireless network node and located inside the vehicle on which the wireless network node is mounted;

a volume of uplink traffic for all UEs connected to the wireless network node and located inside the vehicle on which the wireless network node is mounted;

a volume of downlink traffic for all UEs connected to the wireless network node and located outside the vehicle on which the wireless network node is mounted;

a volume of uplink traffic for all UEs connected to the wireless network node and located outside the vehicle on which the wireless network node is mounted;

a bit rate for downlink traffic;

a bit rate for uplink traffic; or

any combination thereof.
The first BS of Claim 11, wherein the bit rate comprises a guaranteed flow bit rate (GFBR) or a maximum flow bit rate (MFBR) .
The first BS of any of Claims 10-12, wherein the response message is an F1 setup response message which indicates:

the number of UEs allowed to be handed over from the second BS to the first BS;

a volume of downlink traffic allowed; or

a volume of uplink traffic allowed.
A second base station (BS) , comprising:

at least one memory; and

at least one processor coupled with the at least one memory and configured to cause the second BS to:

initiate a distributed unit (DU) migration of a wireless network node from the second BS to a first BS; and

receive an F1 setup outcome notification message from the wireless network node, wherein the F1 setup outcome notification message indicates: a cause value of an F1 setup failure associated with the DU migration of the wireless network node, or a waiting time before reinitiating another F1 setup procedure or another DU migration procedure to the first BS.
A method for wireless communication, comprising:

transmitting an F1 setup request message to a first base station (BS) , the F1 setup request message being for performing a distributed unit (DU) migration of the wireless network node from a second BS to the first BS, and wherein the F1 setup request message comprises information relating to a user equipment (UE) traffic profile of one or more UEs as served by the wireless network node; and

in response to transmitting the F1 setup request message, receiving a response message to the F1 setup request message from the first BS.
The method of Claim 15, wherein the information relating to the UE traffic profile indicates:

the number of UEs connected to the wireless network node;

the number of UEs connected to the wireless network node and located inside a vehicle on which the wireless network node is mounted;

the number of UEs connected to the wireless network node and located outside the vehicle on which the wireless network node is mounted;

a volume of downlink traffic for all UEs connected to the wireless network node;

a volume of uplink traffic for all UEs connected to the wireless network node;

a volume of downlink traffic for all UEs connected to the wireless network node and located inside the vehicle on which the wireless network node is mounted;

a volume of uplink traffic for all UEs connected to the wireless network node and located inside the vehicle on which the wireless network node is mounted;

a volume of downlink traffic for all UEs connected to the wireless network node and located outside the vehicle on which the wireless network node is mounted;

a volume of uplink traffic for all UEs connected to the wireless network node and located outside the vehicle on which the wireless network node is mounted;

a bit rate for downlink traffic;

a bit rate for uplink traffic; or

any combination thereof.
The method of Claim 16, wherein the bit rate comprises a guaranteed flow bit rate (GFBR) or a maximum flow bit rate (MFBR) .
The method of any of Claims 15-17, wherein the response message is an F1 setup response message which indicates:

the number of UEs allowed to be handed over from the second BS to the first BS;

a volume of downlink traffic allowed; or

a volume of uplink traffic allowed.
The method of any of Claims 15-17, wherein the response message is an F1 setup failure message which indicates:

a cause value of the F1 setup failure; or

a waiting time before reinitiating another F1 setup procedure or another DU migration procedure to the first BS.
The method of any of Claims 15-17, further comprising transmitting an F1 setup outcome notification message to the second BS based on the response message.