WO2025194389A1

WO2025194389A1 - Devices and methods of communication

Info

Publication number: WO2025194389A1
Application number: PCT/CN2024/082758
Authority: WO
Inventors: Jinhui WEN; Gang Wang
Original assignee: NEC Corp
Current assignee: NEC Corp
Priority date: 2024-03-20
Filing date: 2024-03-20
Publication date: 2025-09-25
Anticipated expiration: 2026-09-20

Abstract

Embodiments of the present disclosure relate to devices and methods of communication. In one aspect, upon determination that a condition for transmitting first information of flow control for WAB is fulfilled, a first device may transmit, to a second device via at least one of downlink control information, a MAC CE, a MAC subheader or a control PDU, the first information of flow control comprising at least one of the following: an identity of a group or information of a granularity, information of a buffer size, information of a direction of a traffic, or information of a congestion. Based on the first information, the second device may perform the flow control. In this way, a flow control for WAB may be achieved by means of a flow control polling and feedback, and user experience may be improved.

Description

DEVICES AND METHODS OF COMMUNICATION

TECHNICAL FIELD

Embodiments of the present disclosure generally relate to the field of telecommunication, and in particular, to devices and methods of communication for wireless access backhaul (WAB) .

BACKGROUND

In some outdoor environments, availability of vehicles equipped with mobile base station relays (e.g., vehicle-mounted relays (VMR) ) , either following a certain known/predictable itinerary (e.g., buses, trams, etc. ) , or situated in convenient locations (e.g., outside stadiums, hot-spot areas, emergency sites, etc. ) , may provide very opportunistic boost to cellular coverage and capacity. Those relays, using a fifth generation (5G) wireless backhaul toward a macro network, may indeed offer better 5G coverage and connectivity to neighboring user equipment (UE) . In order to support a simplified relay solution and reduce signaling overhead of group handover, it is proposed to study WAB which has full gNB and UE functionality on a vehicle and works as a relay node.

SUMMARY

In general, embodiments of the present disclosure provide methods, devices and computer storage media of communication for WAB.

In a first aspect, there is provided a first device. The first device comprises a processor configured to cause the first device to: determine that a condition for transmitting first information of flow control for WAB is fulfilled; and transmit, to a second device via at least one of downlink control information, a medium access control (MAC) control element (CE) , a MAC subheader or a control protocol data unit (PDU) , the first information of flow control comprising at least one of the following: an identity of a group or information of a granularity, information of a buffer size, information of a direction of a traffic, or information of a congestion.

In a second aspect, there is provided a second device. The second device comprises a processor configured to cause the second device to: receive, from a first device via at least one of downlink control information, a MAC CE, a MAC subheader or a control PDU, first information of flow control for WAB comprising at least one of the following: an identity of a group or information of a granularity, information of a buffer size, information of a direction of a traffic, or information of a congestion; and perform the flow control based on the first information.

In a third aspect, there is provided a third device. The third device comprises a processor configured to cause the third device to: transmit, to a fourth device, fourth information assistant for flow control for WAB, the fourth information comprising at least one of the following: an identity of a first cell in a set of first cells served by the third device, a preferred maximum throughput for the first cell, a preferred maximum bandwidth for the first cell, or a preferred size threshold for a buffer size.

In a fourth aspect, there is provided a fourth device. The fourth device comprises a processor configured to cause the fourth device to: receive, from a third device, fourth information assistant for flow control for WAB, the fourth information comprising at least one of the following: an identity of a first cell in a set of first cells served by the third device, a preferred maximum throughput for the first cell, a preferred maximum bandwidth for the first cell, or a preferred size threshold for a buffer size; and perform the flow control based on the fourth information.

In a fifth aspect, there is provided a method of communication. The method comprises: determining, at a first device, that a condition for transmitting first information of flow control for WAB is fulfilled; and transmitting, to a second device via at least one of downlink control information, a MAC CE, a MAC subheader or a control PDU, the first information of flow control comprising at least one of the following: an identity of a group or information of a granularity, information of a buffer size, information of a direction of a traffic, or information of a congestion.

In a sixth aspect, there is provided a method of communication. The method comprises: receiving, at a second device and from a first device via at least one of downlink control information, a MAC CE, a MAC subheader or a control PDU, first information of flow control for WAB comprising at least one of the following: an identity of a group or information of a granularity, information of a buffer size, information of a direction of a traffic, or information of a congestion; and performing the flow control based on the first information.

In a seventh aspect, there is provided a method of communication. The method comprises: transmitting, at a third device and to a fourth device, fourth information assistant for flow control for WAB, the fourth information comprising at least one of the following: an identity of a first cell in a set of first cells served by the third device, a preferred maximum throughput for the first cell, a preferred maximum bandwidth for the first cell, or a preferred size threshold for a buffer size.

In an eighth aspect, there is provided a method of communication. The method comprises: receiving, at a fourth device and from a third device, fourth information assistant for flow control for WAB, the fourth information comprising at least one of the following: an identity of a first cell in a set of first cells served by the third device, a preferred maximum throughput for the first cell, a preferred maximum bandwidth for the first cell, or a preferred size threshold for a buffer size; and performing the flow control based on the fourth information.

In a ninth aspect, there is provided a computer readable medium having instructions stored thereon. The instructions, when executed on at least one processor, cause the at least one processor to perform the method according to any of the fifth to eighth aspects of the present disclosure.

Other features of the present disclosure will become easily comprehensible through the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

Through the more detailed description of some embodiments of the present disclosure in the accompanying drawings, the above and other objects, features and advantages of the present disclosure will become more apparent, wherein:

FIG. 1 illustrates an example communication network in which some embodiments of the present disclosure can be implemented;

FIG. 2 illustrates a signaling chart illustrating an example process of communication according to embodiments of the present disclosure;

FIG. 3A illustrates a diagram illustrating an example MAC CE for activation or deactivation of a flow control feedback according to embodiments of the present disclosure;

FIG. 3B illustrates a diagram illustrating an example control PDU for activation or deactivation of a flow control feedback according to embodiments of the present disclosure;

FIG. 4A illustrates a diagram illustrating an example MAC subheader for a flow control polling according to embodiments of the present disclosure;

FIG. 4B illustrates a diagram illustrating another example MAC subheader for a flow control polling according to embodiments of the present disclosure;

FIG. 4C illustrates a diagram illustrating an example MAC CE for a flow control polling according to embodiments of the present disclosure;

FIG. 4D illustrates a diagram illustrating an example control PDU for a flow control polling according to embodiments of the present disclosure;

FIG. 5A illustrates a diagram illustrating an example MAC CE for a flow control feedback according to embodiments of the present disclosure;

FIG. 5B illustrates a diagram illustrating an example control PDU for a flow control feedback according to embodiments of the present disclosure;

FIG. 5C illustrates a diagram illustrating another example control PDU for a flow control feedback according to embodiments of the present disclosure;

FIG. 5D illustrates a diagram illustrating an example MAC subheader for a flow control feedback according to embodiments of the present disclosure;

FIG. 5E illustrates a diagram illustrating another example MAC subheader for a flow control feedback according to embodiments of the present disclosure;

FIG. 6 illustrates a signaling chart illustrating another example process of communication according to embodiments of the present disclosure;

FIG. 7 illustrates a signaling chart illustrating still another example process of communication according to embodiments of the present disclosure;

FIG. 8 illustrates a flowchart of an example method of communication implemented at a first device in accordance with some embodiments of the present disclosure;

FIG. 9 illustrates a flowchart of an example method of communication implemented at a second device in accordance with some embodiments of the present disclosure;

FIG. 10 illustrates a flowchart of an example method of communication implemented at a third device in accordance with some embodiments of the present disclosure;

FIG. 11 illustrates a flowchart of an example method of communication implemented at a fourth device in accordance with some embodiments of the present disclosure; and

FIG. 12 is a simplified block diagram of a device that is suitable for implementing embodiments of the present disclosure.

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

DETAILED DESCRIPTION

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

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

As used herein, the term ‘terminal device’ refers to any device having wireless or wired communication capabilities. Examples of the terminal device include, but not limited to, user equipment (UE) , personal computers, desktops, mobile phones, cellular phones, smart phones, personal digital assistants (PDAs) , portable computers, tablets, wearable devices, internet of things (IoT) devices, ultra-reliable and low latency communications (URLLC) devices, Internet of everything (IoE) devices, machine type communication (MTC) devices, device on vehicle for V2X communication where X means pedestrian, vehicle, or infrastructure/network, devices for integrated access and backhaul (IAB) , space borne vehicles or air borne vehicles in non-terrestrial networks (NTN) including satellites and high altitude platforms (HAPs) encompassing unmanned aircraft systems (UAS) , XR devices including different types of realities such as augmented reality (AR) , mixed reality (MR) and virtual reality (VR) , the unmanned aerial vehicle (UAV) commonly known as a drone which is an aircraft without any human pilot, devices on high speed train (HST) , or image capture devices such as digital cameras, sensors, gaming devices, music storage and playback appliances, or Internet appliances enabling wireless or wired Internet access and browsing and the like. The ‘terminal device’ can further has ‘multicast/broadcast’ feature, to support public safety and mission critical, V2X applications, transparent IPv4/IPv6 multicast delivery, IPTV, smart TV, radio services, software delivery over wireless, group communications and IoT applications. It may also incorporate one or multiple subscriber identity module (SIM) as known as multi-SIM. The term ‘terminal device’ can be used interchangeably with a UE, a mobile station, a subscriber station, a mobile terminal, a user terminal or a wireless device.

As used herein, the term ‘network device’ or ‘network element’ refers to a node in a communication network via which a terminal device accesses the network and receives services from the network. The communication network may be a core network (CN) . The network device or element in CN (also referred to as CN device herein) may refer to a policy control function (PCF) , an access management function (AMF) , a session management function (SMF) , a user plane function (UPF) , unified data management (UDM) , unified data repository (UDR) , an authentication server function (AUSF) , a ProSe key management function (PKMF) , a direct discovery name management function (DDNMF) , a network exposure function (NEF) , etc.

The communication network may be a radio access network (RAN) . The network device or element in RAN (also referred to as a RAN device herein) may refer to a base station (BS) or an access point (AP) , for example, a Node B (NodeB or NB) , an evolved NodeB (eNodeB or eNB) , a next generation NodeB (gNB) , a transmission reception point (TRP) , a remote radio unit (RRU) , a radio head (RH) , a remote radio head (RRH) , an IAB node, a low power node such as a femto node, a pico node, a reconfigurable intelligent surface (RIS) , and the like.

The terminal device or the network device may have artificial intelligence (AI) or machine learning capability. It generally includes a model which has been trained from numerous collected data for a specific function, and can be used to predict some information.

The terminal or the network device may work on several frequency ranges, e.g., FR1 (410 MHz to 7125 MHz) , FR2 (24.25GHz to 71GHz) , frequency band larger than 100GHz as well as Tera Hertz (THz) . It can further work on licensed/unlicensed/shared spectrum. The terminal device may have more than one connection with the network devices under a multi-radio dual connectivity (MR-DC) application scenario. The terminal device or the network device can work on full duplex, flexible duplex and cross division duplex modes.

The embodiments of the present disclosure may be performed in test equipment, e.g., signal generator, signal analyzer, spectrum analyzer, network analyzer, test terminal device, test network device, channel emulator.

In one embodiment, the terminal device may be connected with a first network device and a second network device. One of the first network device and the second network device may be a master node and the other one may be a secondary node. The first network device and the second network device may use different radio access technologies (RATs) . In one embodiment, the first network device may be a first RAT device and the second network device may be a second RAT device. In one embodiment, the first RAT device is eNB and the second RAT device is gNB. Information related with different RATs may be transmitted to the terminal device from at least one of the first network device or the second network device. In one embodiment, first information may be transmitted to the terminal device from the first network device and second information may be transmitted to the terminal device from the second network device directly or via the first network device. In one embodiment, information related with configuration for the terminal device configured by the second network device may be transmitted from the second network device via the first network device. Information related with reconfiguration for the terminal device configured by the second network device may be transmitted to the terminal device from the second network device directly or via the first network device.

As used herein, the singular forms ‘a’ , ‘an’ and ‘the’ are intended to include the plural forms as well, unless the context clearly indicates otherwise. The term ‘includes’ and its variants are to be read as open terms that mean ‘includes, but is not limited to. ’ The term ‘based on’ is to be read as ‘at least in part based on. ’ The term ‘one embodiment’ and ‘an embodiment’ are to be read as ‘at least one embodiment. ’ The term ‘another embodiment’ is to be read as ‘at least one other embodiment. ’ The terms ‘first, ’ ‘second, ’ and the like may refer to different or same objects. Other definitions, explicit and implicit, may be included below.

In some examples, values, procedures, or apparatus are referred to as ‘best, ’ ‘lowest, ’ ‘highest, ’ ‘minimum, ’ ‘maximum, ’ or the like. It will be appreciated that such descriptions are intended to indicate that a selection among many used functional alternatives can be made, and such selections need not be better, smaller, higher, or otherwise preferable to other selections.

In the context of the present disclosure, the term ‘WAB node’ herein refers to a relay that holds full gNB function and UE function. In other words, a WAB node is a RAN node that supports wireless Uu (e.g., new radio (NR) or the sixth generation (6G) ) access links to UEs and wireless Uu links for backhaul to parent RAN nodes. The term ‘WAB node’ may be interchangeably used with ‘VMR’ or ‘relay’ . The term ‘WAB’ may be interchangeably used with ‘wireless backhaul’ .

A WAB node may include a mobile termination and a network termination. For convenience, the mobile termination of the WAB node may also be referred to as a WAB-mobile termination (MT) herein. WAB-MT may refer to a WAB node function that terminates a Uu interface to a parent node using procedures and behaviors specified for UEs unless stated otherwise. In other words, WAB-MT has a UE function.

For convenience, the network termination of the WAB node may also be referred to as a WAB-network termination (NT) herein. WAB-NT refer to a WAB node function that provides a full gNB function for NR access to UE. In other words, WAB-NT has a full gNB function.

In the context of the present disclosure, the term ‘backhaul (BH) base station’ herein may refer to a RAN node that provides NR Uu link for backhauling of a WAB node. The BH base station may be a parent RAN node or cell or gNB of a WAB-MT or WAB node. The term ‘BH base station’ may be interchangeably used with ‘BH gNB’ or ‘RAN device’ or ‘parent RAN node’ or ‘parent node’ or ‘parent gNB’ or ‘cell of WAB-MT’ .

Since a WAB node may serve one or more cells and all data scheduled by the cells may be aggregated on a WAB node/WAB-MT, a link between the WAB node/WAB-MT and its parent node may be a bottleneck for data transmission, and congestion may happen if a data load is huge. Hence, a flow control needs to be considered to improve user experience.

Embodiments of the present disclosure provide solutions of communication for a flow control for WAB. In one aspect, upon determination that a condition for transmitting first information of flow control for WAB is fulfilled, a first device may transmit, to a second device via at least one of downlink control information, a MAC CE, a MAC subheader or a control PDU, the first information of flow control comprising at least one of the following: an identity of a group or information of a granularity, information of a buffer size, information of a direction of a traffic, or information of a congestion. Based on the first information, the second device may perform the flow control. In some embodiments, the first device is a WAB node/WAB-MT, and the second device is a parent node of the WAB node. In some embodiments, the first device is a parent node of a WAB node, and the second device is the WAB node or WAB-MT. In this way, a flow control for WAB may be achieved by means of a flow control polling and feedback, and user experience may be improved.

In another aspect, a third device may transmit, to a fourth device, fourth information assistant for flow control for WAB, the fourth information comprising at least one of the following: an identity of a first cell in a set of first cells served by the third device, a preferred maximum throughput for the first cell, a preferred maximum bandwidth for the first cell, or a preferred size threshold for a buffer size. Based on the fourth information, the fourth device may perform the flow control. In some embodiments, the third device is a WAB node/WAB-MT/WAB-NT, and the fourth device is a parent node of the WAB node. In this way, a scheduling for a maximum data volume for each cell or carrier served by a WAB node may be optimized and a congestion at the WAB node may be avoided. Thus, a flow control for WAB may be achieved.

Principles and implementations of the present disclosure will be described in detail below with reference to the figures.

EXAMPLE OF COMMUNICATION NETWORK

FIG. 1 illustrates a schematic diagram of an example communication network 100 in which some embodiments of the present disclosure can be implemented. As shown in FIG. 1, the communication network 100 may include a terminal device 110, a WAB node 120, a RAN device 130, and a CN device 140. The terminal device 110 may communicate with the RAN device 130 via the WAB node 120, and may communicate with the CN device 140 via the WAB node 120 and the RAN device 130. In this case, the RAN device 130 serves as a parent node of the WAB node 120.

It is to be understood that the number of terminal devices, RAN devices, WAB nodes or CN elements in FIG. 1 is given for the purpose of illustration without suggesting any limitations to the present disclosure. The communication network 100 may include any suitable number of terminal devices and/or RAN devices and/or WAB nodes and/or CN devices adapted for implementing implementations of the present disclosure.

As shown in FIG. 1, the WAB node 120 may include a WAB-MT 121 and a WAB-NT 122. The WAB-MT 121 has a UE function. The WAB-NT 122 has a full gNB function. The terminal device 110 may communicate with the WAB-NT 122 via a wireless Uu access link, and the WAB-MT 121 may communicate with the RAN device 130 via a wireless Uu backhaul link. In some embodiments, a protocol data unit (PDU) session may be established between the WAB-MT 121 and the CN device 140 (e.g., UPF) , and data may be backhauled over the PDU session.

The communications in the communication network 100 may conform to any suitable standards including, but not limited to, global system for mobile communications (GSM) , long term evolution (LTE) , LTE-evolution, LTE-advanced (LTE-A) , NR, wideband code division multiple access (WCDMA) , code division multiple access (CDMA) , GSM EDGE radio access network (GERAN) , machine type communication (MTC) and the like. The embodiments of the present disclosure may be performed according to any generation communication protocols either currently known or to be developed in the future. Examples of the communication protocols include, but not limited to, the first generation (1G) , the second generation (2G) , 2.5G, 2.75G, the third generation (3G) , the fourth generation (4G) , 4.5G, the fifth generation (5G) communication protocols, 5.5G, 5G-advanced networks, or the sixth generation (6G) networks.

In mobile IAB, a mobile IAB node with only IAB-MT and IAB-distributed unit (DU) functionality is mounted on a vehicle. If a mobile IAB-DU migrates from one donor central unit (CU) to another donor CU along movement, all the UEs onboard have to migrate together with the mobile IAB-DU. Such separate MT migration and DU migration together with UE migration make the design very complicated and not easy for implementation. In order to support a simplified VMR solution and reduce signaling overhead of group handover, WAB which has full gNB and UE functionality on the vehicle and works as a relay node is proposed.

For WAB, since a WAB node may serve one or more cells and all data scheduled by the cells may be aggregated on a WAB node/WAB-MT, a link between the WAB node/WAB-MT and its parent node may be a bottleneck for data transmission, and congestion may happen if a data load is huge.

In view of this, embodiments of the present disclosure provide solutions of communication for a flow control for WAB so as to improve user experience. The solutions will be described in detail with reference to FIGs. 2 to 7 below.

EXAMPLE IMPLEMENTATION OF FLOW CONTROL FEEDBACK FOR WAB

Embodiments of the present disclosure provide a solution of a flow control feedback. In the solution, if a condition for transmitting information (for convenience, also referred to as first information herein) of flow control for WAB is fulfilled, a first device may transmit such information to a second device for the flow control. In the context of the present disclosure, a transmission of the first information may also be called as a flow control feedback.

In some embodiments, the first device may be a WAB node/WAB-MT, and the second device is a parent node of the WAB node. For these embodiments, more details of the solution of flow control feedback will be described in connection with FIGs. 2 to 5E below.

FIG. 2 illustrates a signaling chart illustrating an example process 200 of communication according to embodiments of the present disclosure. For the purpose of discussion, the process 200 will be described with reference to FIG. 1. The process 200 may involve the WAB node 120/WAB-MT121 and the RAN device 130 as illustrated in FIG. 1. It is to be understood that the steps and the order of the steps in FIG. 2 are merely for illustration, and not for limitation. For example, the order of the steps may be changed. Some of the steps may be omitted or any suitable additional steps may be added. In this example, the RAN device 130 is a parent node of the WAB node 120.

As shown in FIG. 2, the RAN device 130 may transmit 210, to the WAB node 120/WAB-MT121, a configuration for a transmission of the first information, i.e., a configuration for a flow control feedback. In some embodiments, the RAN device 130 may transmit the configuration via a RRC signaling. It is to be understood that any other suitable ways may also be feasible.

In some embodiments, the configuration may comprise an indication of whether the transmission of the first information is enabled or disabled. For example, a field may be introduced to indicate whether the flow control feedback is enabled or disabled.

In some embodiments, the configuration may comprise an identity (ID) of a group. That is, the flow control feedback may be reported per group. In some embodiments, the group may comprise one or more logical channels (LCHs) or radio link control (RLC) channels or quality of service (QoS) flows or logical channel groups (LCGs) or data radio bearers (DRBs) or cells or cell groups or terminal devices or granularities in adaptive layers for WAB (may also referred to as WAB adaptive layers herein) . It is to be understood that the group may also be defined according to any other suitable ways.

In some embodiments, the configuration may comprise information of a granularity. That is, the flow control feedback may be reported according to the granularity. In some embodiments, the information of the granularity may comprise an ID of a LCH or RLC channel or QoS flow or LCG or DRB or cell or cell group or terminal device or granularity in a WAB adaptive layer. Alternatively, the information of the granularity may comprise a bitmap for a set of LCHs or RLC channels or QoS flows or LCGs or DRBs or cells or cell groups or terminal devices or granularities in WAB adaptive layers. In this case, the bitmap may comprise a set of bits, and each bit indicate whether the flow control feedback is performed for a corresponding LCH or RLC channel or QoS flow or LCG or DRB or cell or cell group or terminal device or granularity in a WAB adaptive layer.

In some embodiments, the cell or cell group may be a cell or cell group served by the WAB node 120. In some embodiments, the cell or cell group may be a serving cell or cell group of the WAB-MT 121.

In some embodiments, the granularity in the WAB adaptive layer may comprise a channel or an egress link or a bearer or a route path defined by the WAB adaptive layer. It is to be understood that any other suitable granularities may also be defined by the WAB adaptive layer.

In some embodiments, the configuration may comprise a type of the transmission of the first information, i.e., a flow control feedback type. In some embodiments, a field may be introduced to configure the type or granularity of the flow control feedback. In some embodiments, the type or granularity of the flow control feedback may indicate that the flow control feedback is per LCH or per RLC channel or per QoS flow or per LCG or per DRB or per cell or per cell group or per terminal device or per granularity in a WAB adaptive layer or per group.

It is to be understood that the configuration for flow control feedback may comprise any combination of the above information or any other suitable information or information combination.

For illustration, an example configuration for flow control feedback may be described as below.

WAP-Config :: = SEQUENCE {

flowControlFeedbackType ENUMERATED {perLCH, perRLC-Channel, perQoSFlow, perLCG, perDRB, perCell, perCellGroup, perUE, perWABID, perGroup} //This field is used to configure the type or granularity of flow control feedback. Value perLCH indicates that the WAB node shall provide flow control feedback per logical channel, value perRLC-Channel indicates that the WAB node shall provide flow control feedback per RLC channel, value perQoSFlow indicates that the WAB node shall provide flow control feedback per QoS flow, value perLCG indicates that the WAB node shall provide flow control feedback per LCG, value perDRB indicates that the WAB node shall provide flow control feedback per DRB, value perCell indicates that the WAB node shall provide flow control feedback per cell, value perCellGroup indicates that the WAB node shall provide flow control feedback per cell group, value perUE indicates that the WAB node shall provide flow control feedback per UE, value perWABID indicates that the WAB node shall provide flow control feedback per granularity in WAB adaptive layer, value perGroup indicates that the WAB node shall provide flow control feedback per group.

...

}

In this example configuration, an information element (IE) ‘WAP-Config’ denotes a configuration of a flow control feedback, and an IE ‘flowControlFeedbackType’ denotes a type or granularity of the flow control feedback.

The WAB node 120/WAB-MT 121 may apply the flow control feedback based on the configuration of the flow control feedback. For illustration, an example procedure may be described as below.

The WAB-MT shall:

1> if the wap-Config is set to setup:

2> if flowControlFeedbackType is included:

3> configure the WAB entity or MAC/RLC/PDCP/SDAP entity to apply the flow control feedback according to the configuration.

In this example procedure, an IE ‘wap-Config’ denotes a configuration of a flow control feedback, and an IE ‘flowControlFeedbackType’ denotes a type or granularity of the flow control feedback.

With reference to FIG. 2, the RAN device 130 may transmit 220, to the WAB node 120/WAB-MT 121, information (for convenience, also referred to as third information herein) for activating or deactivating a transmission of the first information (i.e., for activating or deactivating the flow control feedback) .

In some embodiments, the third information may comprise the ID of the group. That is, the activation or deactivation may be performed per group. In some embodiments, the third information may comprise the information of the granularity. That is, the activation or deactivation may be performed according to the granularity or per granularity. In some embodiments, the third information may comprise an indication of activating or deactivating the transmission of the first information. In some embodiments, the third information may comprise a PDU type indicating a control PDU for an activation or deactivation of the transmission of the first information. In some embodiments, the third information may comprise an indication of whether a PDU is a data PDU or control PDU.

In some embodiments, the RAN device 130 may transmit the third information via a MAC CE. In some embodiments, the RAN device 130 may transmit the third information via a control PDU. It is to be understood that any other suitable ways may also be feasible. For illustration, some example embodiments may be described in connection with FIGs. 3A and 3B.

FIG. 3A illustrates a diagram illustrating an example MAC CE 300A for activation or deactivation of a flow control feedback according to embodiments of the present disclosure. As shown in FIG. 3A, the MAC CE 300A may include A/D fields 311 and granularity fields 312. An A/D field 311 may indicate whether to activate or deactivate the flow control feedback of the indicated granularity. For example, the A/D field 311 may be set to 1 to indicate activation, and set to 0 to indicate deactivation. It is to be understood that any other suitable values may also be feasible, and the present disclosure does not limit this aspect. A granularity field 312 may indicate a granularity, e.g., an LCH ID or RLC channel ID or QoS flow ID or LCG ID or DRB ID or cell ID or cell group ID or WAB ID or group ID. Here, the WAB ID refers to an ID of a granularity in a WAB adaptive layer. That is, this field may indicate an ID of a LCH or RLC channel or QoS flow or LCG or DRB or cell or cell group or granularity defined by a WAB adaptive layer whose flow control feedback is activated or deactivated. It is to be noted that one or more types of IDs described here may be in a MAC PDU or control PDU.

With the MAC CE 300A, activation or deactivation status of a set of LCHs or RLC channels or QoS flows or LCGs or DRBs or cells or cell groups or granularities defined by WAB adaptive layers may be indicated.

FIG. 3B illustrates a diagram illustrating an example control PDU 300B for activation or deactivation of a flow control feedback according to embodiments of the present disclosure. As shown in FIG. 3B, the control PDU 300B may include a D/C field 321, a PDU Type field 322, an R field 323, an A/D field 324, and a granularity field 325. The D/C field 321 may indicate whether the PDU is a data PDU or control PDU. The PDU Type field 322 may indicate a specific value used to indicate that the corresponding PDU is a control PDU for flow control feedback activation or deactivation. The R field 323 may indicate a reserved bit, e.g., set to 0. The A/D field 324 may indicate whether to activate or deactivate the flow control feedback of the indicated granularity. For example, the A/D field 324 may be set to 1 to indicate activation, and set to 0 to indicate deactivation. It is to be understood that any other suitable values may also be feasible, and the present disclosure does not limit this aspect. The granularity field 325 may indicate an ID of a LCH or RLC channel or QoS flow or LCG or DRB or cell or cell group or granularity defined by a WAB adaptive layer whose flow control feedback is activated or deactivated. It is to be noted that one or more types of IDs described here may be in a MAC PDU or control PDU.

Continuing to refer to FIG. 2, based on an indication of the third information from the RAN device 130, the WAB node 120/WAB-MT 121 may activate or deactivate 222 the flow control feedback. In some alternative embodiments, the WAB node 120/WAB-MT 121 may activate or deactivate 222 the flow control feedback without the indication of the third information. In some embodiments, upon reception of the configuration for the flow control feedback, the WAB node 120/WAB-MT 121 may consider that the flow control feedback is activated.

Upon activation of the flow control feedback, the WAB node 120/WAB-MT 121 may apply the flow control feedback. With reference to FIG. 2, the WAB node 120/WAB-MT 121 may determine 230 that a condition for transmitting first information of flow control for WAB is fulfilled.

As shown in FIG. 2, in some embodiments, the RAN device 130 may transmit 231 information (for convenience, also referred to as second information herein) of a flow control polling to the WAB node 120/WAB-MT 121. Upon reception of the second information of the flow control polling, the WAB node 120/WAB-MT 121 may determine that the condition for transmitting the first information is fulfilled.

In some embodiments, the second information may comprise an indication of whether the first information is requested (i.e., whether flow control feedback information is requested) . In some embodiments, the second information may comprise a logical channel identity (LCID) or extended LCID (eLCID) value for the flow control polling. In some embodiments, the second information may comprise a PDU type indicating a control PDU for the flow control polling. In some embodiments, the second information may comprise an indication of whether a PDU is a data PDU or control PDU. It is to be understood that the second information may comprise any combination of the above information or any other suitable information or information combination.

In some embodiments, the RAN device 130 may transmit the second information of the flow control polling via at least one of DCI, a MAC CE, a MAC subheader or a control PDU. For illustration, some example embodiments will be described in connection with FIGs. 4A to 4D below.

FIG. 4A illustrates a diagram illustrating an example MAC subheader 400A for a flow control polling according to embodiments of the present disclosure. As shown in FIG. 4A, the MAC subheader 400A may include a R field 411, a R or Polling field 412 and a LCID field 413. The R field 411 is a reserved bit, e.g., set to 0. The R or Polling field 412 is a reserved bit or indicates whether to request flow control feedback information. For example, value 0 may be used to indicate that the flow control feedback information is not requested, and value 1 may be used to indicate that the flow control feedback information is requested. The LCID field 413 indicates a dedicated LCID value for flow control polling.

FIG. 4B illustrates a diagram illustrating another example MAC subheader 400B for a flow control polling according to embodiments of the present disclosure. As shown in FIG. 4B, the MAC subheader 400B may include a R field 421, a R or Polling field 422, a LCID field 423 and eLCID field 424. The R field 421 is a reserved bit, e.g., set to 0. The R or Polling field 422 is a reserved bit or indicates whether to request flow control feedback information. For example, value 0 may be used to indicate that the flow control feedback information is not requested, and value 1 may be used to indicate that the flow control feedback information is requested. It is to be understood that any other suitable values may also be feasible. The LCID field 423 and the eLCID field 424 indicate a dedicated eLCID value for flow control polling.

FIG. 4C illustrates a diagram illustrating an example MAC CE 400C for a flow control polling according to embodiments of the present disclosure. As shown in FIG. 4C, the MAC CE 400C may include a Polling field 431 and R fields 432. The Polling field 431 indicates whether to request flow control feedback information. For example, value 0 may be used to indicate that the flow control feedback information is not requested, and value 1 may be used to indicate that the flow control feedback information is requested. It is to be understood that any other suitable values may also be feasible. The R fields 432 are reserved bits, e.g., set to 0.

FIG. 4D illustrates a diagram illustrating an example control PDU 400D for a flow control polling according to embodiments of the present disclosure. As shown in FIG. 4D, the control PDU 400D may include a D/C field 441, a PDU Type field 442, a R or polling field 443, and R fields 444. The D/C field 441 may indicate whether the PDU is a data PDU or control PDU. The PDU Type field 442 may indicate a specific value used to indicate that the corresponding PDU is a control PDU for flow control polling. The R fields 444 may indicate reserved bits, e.g., set to 0. It is to be noted that the control PDU for flow control polling may be defined in a RLC or packet data convergence protocol (PDCP) or service data adaptation protocol (SDAP) layer, or a newly defined WAB adaptive layer, etc.

Continuing to refer to FIG. 2, in some embodiments, the WAB node 120/WAB-MT 121 may determine 232 that a buffer load at the WAB node 120/WAB-MT 121 is higher than or equal to a load threshold. In this case, the WAB node 120/WAB-MT 121 may determine that the condition for transmitting the first information is fulfilled. In the context of the present disclosure, the term ‘buffer load’ may be interchangeably used with ‘buffer size’ , and the term ‘load threshold’ may be interchangeably used with ‘load level’ or ‘load ratio’ or ‘size threshold’ or ‘size level’ or ‘size ratio’ .

In some embodiments, the load threshold may be configured. For example, the WAB node 120/WAB-MT 121 may receive a configuration of the load threshold from the RAN device 130 via a RRC signaling. In another example, the WAB node 120/WAB-NT 121 may receive a configuration of the load threshold from the RAN device 130 via a non-access stratum (NAS) signaling. In some embodiments, the load threshold may be predefined. In some embodiments, the load threshold may be determined by WAB node/WAB-MT implementation.

In some embodiments, the buffer load may be calculated per UE or per LCH or per RLC channel or per QoS flow or per LCG or per DRB or per cell or per cell group or per ID/granularity defined by a WAB adaptive Layer (e.g., per channel, bearer, egress link or route path ID) or per group. In some embodiments, the load threshold may be configured per UE or per LCH or per RLC channel or per QoS flow or per LCG or per DRB or per cell or per cell group or per ID/granularity defined by a WAB adaptive Layer (e.g., per channel, bearer, egress link or route path ID) or per group.

Continuing to refer to FIG. 2, in some embodiments, the WAB node 120/WAB-MT 121 may receive 233, from the WAB-NT 122, a request for reporting the first information of flow control. In this case, the WAB node 120/WAB-MT 121 may determine that the condition for transmitting the first information is fulfilled. In some embodiments, the WAB node 120 or the parent node may collect flow control information and then trigger the WAB-MT 121 or the parent node to send the flow control feedback information (i.e., the first information) .

As shown in FIG. 2, if the condition for transmitting the first information is fulfilled, the WAB node 120/WAB-MT 121 may transmit 240 the first information of flow control to the RAN device 130.

In some embodiments, the first information may comprise information of a granularity for the flow control feedback. In some embodiments, the information of the granularity may comprise an ID of a LCH or RLC channel or QoS flow or LCG or DRB or cell or cell group or terminal device or granularity in a WAB adaptive layer. Alternatively, the information of the granularity may comprise a bitmap for a set of LCHs or RLC channels or QoS flows or LCGs or DRBs or cells or cell groups or terminal devices or granularities in WAB adaptive layers.

In some embodiments, the first information may comprise the ID of the group. The group may contain one or more granularities as described above.

In some embodiments, the first information may comprise information of a buffer size (e.g., for the corresponding granularity or MAC entity/terminal device) . In some embodiments, the information of the buffer size of the group may comprise at least one of the following: an available or remaining buffer size, an occupied or predicted buffer size, or an index (also referred to as BS index herein) of a buffer size level in a buffer size table.

In some embodiments, the buffer size table may indicate an available or remaining buffer size or traffic volume the WAB node 120/WAB-MT 121 should or can send. In some embodiments, the buffer size table may indicate an occupied or predicted buffer size or traffic volume the WAB node 120/WAB-MT 121 should or can send. In some embodiments, the buffer size table may be introduced to indicate buffer size levels or traffic volumes for the flow control feedback.

In some embodiments, the first information may comprise information of a direction of a traffic that the flow control reports. For example, the information of the direction of the traffic may comprise an ingress or egress indication. In another example, the information of the direction of the traffic may comprise an uplink or downlink indication.

In some embodiments, the first information may comprise information of a congestion. That is, the WAB node 120/WAB-MT 121 may determine whether the congestion happens or flow control should be performed. In some embodiments, the information of the congestion may comprise at least one of the following: an indication of whether the congestion happens, or a LCH or RLC channel or QoS flow or LCG or DRB or cell or cell group or terminal device or granularity in a WAB adaptive layer that is congested.

It is to be understood that the first information may comprise any suitable combinations of the above information and any other suitable information or information combination.

In some embodiments, the WAB node 120/WAB-MT 121 may transmit the first information via at least one of DCI, a MAC CE, a MAC subheader or a control PDU. For illustration, some example embodiments will be described in connection with FIGs. 5A to 5E below.

FIG. 5A illustrates a diagram illustrating an example MAC CE 500A for a flow control feedback according to embodiments of the present disclosure. As shown in FIG. 5A, the MAC CE 500A may include a granularity field 511 and an information field 512. The granularity field 511 may indicate a granularity, e.g., an LCH ID or RLC channel ID or QoS flow ID or LCG ID or DRB ID or cell ID or cell group ID or WAB ID or group ID. That is, this field may indicate an ID of a LCH or RLC channel or QoS flow or LCG or DRB or cell or cell group or granularity defined by a WAB adaptive layer whose flow control information is provided in the flow control feedback. It is to be noted that one or more types of IDs described here may be in a MAC PDU or control PDU.

The information field 512 may indicate the information of buffer size (BS) such as a predicted/available buffer size or a BS index. Alternatively, the information field 512 may indicate the information of congestion, e.g., whether the congestion happens. For example, value 1 may be used to indicate congested, and value 0 may be used to indicate not congested. It is to be understood that any other suitable values may also be feasible.

With the MAC CE 500A, flow control information of a set of groups or LCHs or RLC channels or QoS flows or LCGs or DRBs or cells or cell groups or granularities defined by WAB adaptive layers may be indicated.

FIG. 5B illustrates a diagram illustrating an example control PDU 500B for a flow control feedback according to embodiments of the present disclosure. As shown in FIG. 5B, the control PDU 500B may include a D/C field 521, a PDU Type field 522, and an information field 523. The D/C field 521 may indicate whether the PDU is a data PDU or control PDU. The PDU Type field 522 may indicate a specific value used to indicate that the corresponding PDU is a control PDU for flow control feedback. The information field 523 may indicate the information of BS such as a predicted/available buffer size or a BS index. Alternatively, the information field 523 may indicate the information of congestion, e.g., whether the congestion happens. For example, value 1 may be used to indicate congested, and value 0 may be used to indicate not congested. It is to be understood that any other suitable values may also be feasible.

In some embodiments, the control PDU may be defined in RLC or PDCP or SDAP layer or newly defined WAB adaptive layer. FIG. 5C illustrates a diagram illustrating another example control PDU 500C for a flow control feedback according to embodiments of the present disclosure. As shown in FIG. 5C, the control PDU 500C may include a D/C field 531, a PDU Type field 532, an ID field 533 and an information field 534. The D/C field 531 may indicate whether the PDU is a data PDU or control PDU. The PDU Type field 532 may indicate a specific value used to indicate that the corresponding PDU is a control PDU for flow control feedback. The ID field 533 may indicate an ID or granularity defined in a WAB adaptive layer. The information field 534 may indicate the information of BS such as a predicted/available buffer size or a BS index. Alternatively, the information field 534 may indicate the information of congestion, e.g., whether the congestion happens. For example, value 1 may be used to indicate congested, and value 0 may be used to indicate not congested. It is to be understood that any other suitable values may also be feasible.

FIG. 5D illustrates a diagram illustrating an example MAC subheader 500D for a flow control feedback according to embodiments of the present disclosure. As shown in FIG. 5D, the MAC subheader 500D may include a R field 541, a R or congested field 542, and a LCID field 543. The R field 541 is a reserved bit, e.g., set to 0. The R or congested field 542 is a reserved bit or indicates whether a congestion happens. For example, value 0 may be used to indicate that the congestion does not happen, and value 1 may be used to indicate that the congestion happens. It is to be understood that any other suitable values may also be feasible. The LCID field 543 indicates a dedicated LCID value for flow control feedback. The dedicated LCID value may indicate that the congestion happens or flow control is needed.

FIG. 5E illustrates a diagram illustrating another example MAC subheader 500E for a flow control feedback according to embodiments of the present disclosure. As shown in FIG. 5E, the MAC subheader 500E may include a R field 551, a R or congested field 552, and a LCID field 553 and eLCID field 554. The R field 551 is a reserved bit, e.g., set to 0. The R or congested field 552 is a reserved bit or indicates whether a congestion happens. For example, value 0 may be used to indicate that the congestion does not happen, and value 1 may be used to indicate that the congestion happens. It is to be understood that any other suitable values may also be feasible. The LCID field 553 and the eLCID field 554 indicate a dedicated eLCID value for flow control feedback. The dedicated eLCID value may indicate that the congestion happens or flow control is needed.

For illustration, an example procedure of flow control feedback may be described as below.

If at least one of the following conditions is satisfied,

- when a flow control polling (e.g., via a DCI, MAC subheader, MAC CE or Control PDU) is received, or

- when a flow control feedback is triggered due to the buffer load exceeding a certain level or threshold, or

- when a flow control report request is received at WAB-MT,

at least one of the following actions shall be performed (e.g., by MAC /RLC /PDCP /SDAP entity or WAP entity (e.g., entity defined in WAB adaptive layer) )

- construct a MAC CE or Control PDU for flow control feedback;

- submit the MAC CE or Control PDU to lower layer or the egress channel/link.

Continuing to refer to FIG. 2, upon reception of the first information, the RAN device 130 may perform 250 the flow control based on the first information. In some embodiments, if an available or remaining buffer size indicated in the first information is smaller than or equal to a size threshold, the RAN device 130 may determine that the congestion happens. For example, if a traffic volume/buffer size (e.g., available/remaining traffic volume/buffer size) indicated by a DCI, MAC CE or control PDU for flow control feedback is smaller than or equal to the size threshold, a corresponding entity may consider that the congestion happens (e.g., consider a corresponding link/cell/path or other granularity as congested) , and/or indicate the congestion information to an upper layer.

In some embodiments, if an occupied or predicted buffer size indicated in the first information is greater than or equal to the size threshold, the RAN device 130 may determine that the congestion happens. For example, if a traffic volume/buffer size (e.g., current buffer status) indicated by a DCI, MAC CE or control PDU for flow control feedback is greater than or equal to the size threshold, a corresponding entity may consider that the congestion happens (e.g., consider a corresponding link/cell/path or other granularity as congested) , and/or indicate the congestion information to an upper layer.

In some embodiments, the size threshold may be configured. For example, the RAN device 130 may receive a configuration of the size threshold from the CN device 140 via a F1 application protocol (F1AP) signaling. In some embodiments, the size threshold may be predefined. In some embodiments, the size threshold may be determined by network implementation.

With the process 200, a flow control for WAB may be achieved by means of a flow control polling from a parent node to a WAB node/WAB-MT and feedback from the WAB node/WAB-MT to the parent node. Accordingly, user experience may be improved.

In some alternative embodiments for the solution of flow control feedback as described above, the first device may be a parent node of a WAB node, and the second device may be the WAB node or WAB-MT. For these embodiments, more details of the solution of flow control feedback will be described in connection with FIG. 6 below.

FIG. 6 illustrates a signaling chart illustrating another example process 600 of communication according to embodiments of the present disclosure. For the purpose of discussion, the process 600 will be described with reference to FIG. 1. The process 600 may involve the WAB node 120/WAB-MT 121 and the RAN device 130 as illustrated in FIG. 1. It is to be understood that the steps and the order of the steps in FIG. 6 are merely for illustration, and not for limitation. For example, the order of the steps may be changed. Some of the steps may be omitted or any suitable additional steps may be added. In this example, the RAN device 130 is a parent node of the WAB node 120.

As shown in FIG. 6, the RAN device 130 may determine 610 that a condition for transmitting sixth information of flow control for WAB is fulfilled. The sixth information is similar to the first information, and thus details of the sixth information are not repeated here for conciseness.

With reference to FIG. 6, in some embodiments, the WAB node 120/WAB-MT 121 may transmit 611 seventh information of a flow control polling to the RAN device 130. Upon reception of the information of the flow control polling, the RAN device 130 may determine that the condition for transmitting the first information is fulfilled. The seventh information is similar to the second information, and thus details of the seventh information are not repeated here for conciseness.

With reference to FIG. 6, in some embodiments, the RAN node 130 may determine 612 that a buffer load at the RAN node 130 is higher than or equal to a further load threshold. In this case, the RAN node 130 may determine that the condition for transmitting the first information is fulfilled.

In some embodiments, the further load threshold may be configured. For example, the RAN device 130 may receive a configuration of the further load threshold from the CN device 140 via a F1AP signaling. In some embodiments, the further load threshold may be predefined. In some embodiments, the further load threshold may be determined by network implementation.

Continuing to refer to FIG. 6, if the condition for transmitting the first information is fulfilled, the RAN device 130 may transmit 620 the sixth information of flow control to the WAB node 120/WAB-MT 121.

Continuing to refer to FIG. 6, upon reception of the sixth information, the WAB node 120/WAB-MT 121 may perform 630 the flow control based on the sixth information. In some embodiments, if an available or remaining buffer size indicated in the sixth information is smaller than or equal to a further size threshold, the RAN device 130 may determine that the congestion happens. For example, if a traffic volume/buffer size (e.g., available/remaining traffic volume/buffer size) indicated by a DCI, MAC CE or control PDU for flow control feedback is smaller than or equal to the further size threshold, a corresponding entity may consider that the congestion happens (e.g., consider a corresponding link/cell/path or other granularity as congested) , and/or indicate the congestion information to an upper layer.

In some embodiments, if an occupied or predicted buffer size indicated in the sixth information is greater than or equal to the further size threshold, the RAN device 130 may determine that the congestion happens. For example, if a traffic volume/buffer size (e.g., current buffer status) indicated by a DCI, MAC CE or control PDU for flow control feedback is greater than or equal to the further size threshold, a corresponding entity may consider that the congestion happens (e.g., consider a corresponding link/cell/path or other granularity as congested) , and/or indicate the congestion information to an upper layer.

In some embodiments, the further size threshold may be configured. For example, the RAN device 130 may receive a configuration of the further size threshold from the CN device 140 via a F1AP signaling. In some embodiments, the further size threshold may be predefined. In some embodiments, the further size threshold may be determined by network implementation.

It is to be understood that a transmission of the sixth information is similar to that of the first information, and thus is not repeated here for conciseness. The transmission of the seventh information is similar to that of the second information, and thus is also not repeated here for conciseness.

With the process 600, a flow control for WAB may be achieved by means of a flow control polling from a WAB node/WAB-MT to a parent node and feedback from the parent node to the WAB node/WAB-MT. Accordingly, user experience may be improved.

EXAMPLE IMPLEMENTATION OF ASSISTANCE INFORMATION FOR FLOW CONTROL OF WAB

Embodiments of the present disclosure also provide a solution of a flow control based on assistance information. The solution will be described in connection with FIG. 7.

FIG. 7 illustrates a signaling chart illustrating still another example process 700 of communication according to embodiments of the present disclosure. For the purpose of discussion, the process 700 will be described with reference to FIG. 1. The process 700 may involve the WAB node 120 and the RAN device 130 as illustrated in FIG. 1. It is to be understood that the steps and the order of the steps in FIG. 7 are merely for illustration, and not for limitation. For example, the order of the steps may be changed. Some of the steps may be omitted or any suitable additional steps may be added. In this example, the RAN device 130 is a parent node of the WAB node 120.

As shown in FIG. 7, the WAB node 120 may transmit 710 information (also referred to as fourth information herein) assistant for flow control for WAB. In some embodiments, the WAB-MT 121 may report 711 the fourth information to the RAN device 130 via a RRC signaling such as a UE assistance information message. In some embodiments, the WAB- NT 122 may report 712 the fourth information to the RAN device 130 via a Xn signaling such as a XnAP signaling.

In some embodiments, the fourth information may comprise an ID of a first cell (e.g., each first cell or carrier) in a set of first cells served by the WAB node 120/WAB-NT 122. For example, the ID of the first cell may be a cell ID or physical cell identity (PCI) . In some embodiments, the fourth information may comprise a predicted or preferred maximum throughput for the first cell. In some embodiments, the fourth information may comprise a preferred maximum bandwidth (e.g., for frequency (FR) 1 or FR2) for the first cell. In some embodiments, the fourth information may comprise a preferred size threshold for a buffer size. In some embodiments, the preferred size threshold may be reported per UE or per LCH or per RLC channel or per QoS flow or per LCG or per DRB or per cell or per cell group or per ID/granularity defined in a WAB adaptive layer (e.g., per channel, egress link or route path ID) .

Continuing to refer to FIG. 7, upon reception of the fourth information, the RAN device 130 may perform 720 the flow control based on the fourth information.

With reference to FIG. 7, in some embodiments, if the buffer size received from the WAB node 120 is greater than or equal to the preferred size threshold, the RAN device 130 may determine 721 that the flow control needs to be performed or that a congestion happens for the WAB node 120/WAB-MT 121. In this way, the flow control may be facilitated.

In some embodiments, based on the fourth information, the RAN device 130 may do better scheduling accordingly and assign a proper resource for each cell. With reference to FIG. 7, the RAN device 130 may transmit 722, to the WAB node 120/WAB-MT 121, fifth information comprising at least one of the following: an ID of a second cell in a set of second cells scheduled by the WAB node 120/WAB-MT 121, or maximum data volume for the first cell served by the WAB node 120.

As shown in FIG. 7, the WAB node 120/WAB-MT 121 may forward 723 the fifth information to the WAB-NT 122 so as to perform a scheduling based on the fifth information. For example, the second cell served by the WAB node 120 may not schedule data exceeding the maximum data volume.

In this way, a scheduling for a maximum data volume for each cell or carrier served by a WAB node may be optimized and a congestion at the WAB node may be avoided. Thus, a flow control for WAB may be achieved.

It is to be understood that processes or operations in the processes as described in connection with FIGs. 2 to 7 may be separately carried out or in any suitable combinations. The present disclosure does not limit this aspect.

EXAMPLE IMPLEMENTATION OF METHODS

Corresponding to the above processes, embodiments of the present disclosure provide methods of communication implemented at a first device, a second device, a third device and a fourth device. These methods will be described below with reference to FIGs. 8 to 11.

FIG. 8 illustrates a flowchart of an example method 800 of communication implemented at a first device in accordance with some embodiments of the present disclosure. The first device is a WAB node/WAB-MT or a parent node of the WAB node. The WAB node supports wireless access to a terminal device and wireless backhaul to the parent node. For example, the method 800 may be performed at the WAB node 120/WAB-MT 121 or the RAN device 130 as shown in FIG. 1. It is to be understood that the method 800 may include additional blocks not shown and/or may omit some blocks as shown, and the scope of the present disclosure is not limited in this regard.

At block 810, a first device may determine that a condition for transmitting first information of flow control for WAB is fulfilled.

In some embodiments, the first device may be a parent node of a WAB node, and the second device may be the WAB node or a WAB-MT of the WAB node. In these embodiments, the condition may comprise at least one of the following: second information of a flow control polling is received from the second device; or a buffer load at the first device is higher than or equal to a load threshold.

In some embodiments, the first device may be a WAB node or a WAB-MT of the WAB node, and the second device may be a parent node of the WAB node. In these embodiments, the condition may comprise at least one of the following: second information of a flow control polling is received from the second device; a buffer load at the first device is higher than or equal to a load threshold; or a request for reporting the first information of flow control is received from a network termination of the WAB node.

In some embodiments, the second information may comprise at least one of the following: an indication of whether the first information is requested; a LCID or eLCID value for the flow control polling; a PDU type indicating a control PDU for the flow control polling; or an indication of whether a PDU is a data PDU or control PDU.

At block 820, the first device may transmit the first information of flow control to a second device via at least one of downlink control information, a MAC CE, a MAC subheader or a control PDU. In some embodiments, the first information may comprise at least one of the following: an identity of a group or information of a granularity, information of a buffer size, information of a direction of a traffic, or information of a congestion.

In some embodiments, the information of the granularity may comprise one of the following: an identity of a LCH, an identity of a RLC channel, an identity of a QoS flow, an identity of a LCG, an identity of a DRB, an identity of a cell, an identity of a cell group, an identity of a terminal device, an identity of a granularity in an adaptive layer for WAB, or a bitmap for a set of LCHs or RLC channels or QoS flows or LCGs or DRBs or cells or cell groups or terminal devices or granularities in adaptive layers for WAB.

In some embodiments, the information of the buffer size of the group may comprise at least one of the following: an available or remaining buffer size, an occupied or predicted buffer size, or an index of a buffer size level in a buffer size table.

In some embodiments, the information of the congestion may comprise at least one of the following: an indication of whether the congestion happens, or a LCH or a RLC channel or a QoS flow or a LCG or a DRB or a cell or a cell group or a terminal device or a granularity in an adaptive layer for WAB that is congested.

In some embodiments where the first device is a WAB node or a WAB-MT of the WAB node and the second device is a parent node of the WAB node, the first device may further receive, from the second device, a configuration for a transmission of the first information. In some embodiments, the configuration may comprise at least one of the following: an indication of whether the transmission of the first information is enabled or disabled, the identity of the group or the information of the granularity, or a type of the transmission of the first information.

In some embodiments where the first device is a WAB node or a WAB-MT of the WAB node and the second device is a parent node of the WAB node, the first device may further receive, from the second device, third information for activating or deactivating a transmission of the first information. In some embodiments, the third information may comprise at least one of the following: the identity of the group or the information of the granularity; an indication of activating or deactivating the transmission of the first information; a PDU type indicating a control PDU for an activation or deactivation of the transmission of the first information; or an indication of whether a PDU is a data PDU or control PDU.

With the method 800, a flow control feedback for WAB may be carried out.

FIG. 9 illustrates a flowchart of an example method 900 of communication implemented at a second device in accordance with some embodiments of the present disclosure. The second device is a parent node of a WAB node or the WAB node/WAB-MT. The WAB node supports wireless access to a terminal device and wireless backhaul to the parent node. For example, the method 900 may be performed at the RAN device 130 or the WAB node 120/WAB-MT 121 as shown in FIG. 1. It is to be understood that the method 900 may include additional blocks not shown and/or may omit some blocks as shown, and the scope of the present disclosure is not limited in this regard.

At block 910, a second device may receive first information of flow control for WAB from a first device via at least one of downlink control information, a MAC CE, a MAC subheader or a control PDU. In some embodiments, the first device may be a parent node of a WAB node, and the second device may be the WAB node or a WAB-MT of the WAB node. In some embodiments, the first device may be a WAB node or a WAB-MT of the WAB node, and the second device may be a parent node of the WAB node.

In some embodiments, the first information may comprise at least one of the following: an identity of a group or information of a granularity, information of a buffer size, information of a direction of a traffic, or information of a congestion.

At block 920, the second device may perform the flow control based on the first information. In some embodiments, the second device may perform the flow control by: determining that the congestion happens based on at least one of the following: an available or remaining buffer size indicated in the first information is smaller than or equal to a size threshold; or an occupied or predicted buffer size indicated in the first information is greater than or equal to the size threshold.

In some embodiments where the first device is a WAB node or a WAB-MT of the WAB node and the second device is a parent node of the WAB node, the second device may further transmit, to the first device, a configuration for a transmission of the first information. In some embodiments, the configuration may comprise at least one of the following: an indication of whether the transmission of the first information is enabled or disabled, the identity of the group or the information of the granularity, or a type of the transmission of the first information.

In some embodiments where the first device is a WAB node or a WAB-MT of the WAB node and the second device is a parent node of the WAB node, the second device may further transmit, to the first device, third information for activating or deactivating a transmission of the first information. In some embodiments, the third information may comprise at least one of the following: the identity of the group or the information of the granularity; an indication of activating or deactivating the transmission of the first information; a PDU type indicating a control PDU for an activation or deactivation of the transmission of the first information; or an indication of whether a PDU is a data PDU or control PDU.

With the method 900, a flow control for WAB may be carried out based on a flow control feedback information.

FIG. 10 illustrates a flowchart of an example method 1000 of communication implemented at a third device in accordance with some embodiments of the present disclosure. The third device is a WAB node. The WAB node supports wireless access to a terminal device and wireless backhaul to a parent node. For example, the method 1000 may be performed at the WAB node 120 as shown in FIG. 1. It is to be understood that the method 1000 may include additional blocks not shown and/or may omit some blocks as shown, and the scope of the present disclosure is not limited in this regard.

At block 1010, a third device may transmit, to a fourth device, fourth information assistant for flow control for WAB. In some embodiments, the fourth information may comprise at least one of the following: an identity of a first cell in a set of first cells served by the third device, a preferred maximum throughput for the first cell, a preferred maximum bandwidth for the first cell, or a preferred size threshold for a buffer size.

In some embodiments, the third device may be a WAB node, and the fourth device may be a parent node of the WAB node. In some embodiments, the third device may be a WAB-MT of the WAB node, and the third device may transmit the fourth information by transmitting the fourth information via a RRC signaling. In some embodiments, the third device may be a WAB-NT of the WAB node, and the third device may transmit the fourth information by transmitting the fourth information via a Xn signaling.

In some embodiments, the third device may further receive, from the fourth device, fifth information comprising at least one of the following: an identity of a second cell in a set of second cells scheduled by the third device, or maximum data volume for the first cell.

With the method 1000, assistance information for a flow control for WAB may be provided to a parent node of a WAB node, and the flow control of the parent node may be facilitated.

FIG. 11 illustrates a flowchart of an example method 1100 of communication implemented at a fourth device in accordance with some embodiments of the present disclosure. The fourth device is a parent node of a WAB node. The WAB node supports wireless access to a terminal device and wireless backhaul to a parent node. For example, the method 1100 may be performed at the RAN device 130 as shown in FIG. 1. It is to be understood that the method 1100 may include additional blocks not shown and/or may omit some blocks as shown, and the scope of the present disclosure is not limited in this regard.

At block 1110, a fourth device may receive, from a third device, fourth information assistant for flow control for WAB. In some embodiments, the fourth information may comprise at least one of the following: an identity of a first cell in a set of first cells served by the third device, a preferred maximum throughput for the first cell, a preferred maximum bandwidth for the first cell, or a preferred size threshold for a buffer size.

In some embodiments, the third device may be a WAB node, and the fourth device may be a parent node of the WAB node. In some embodiments, the third device may be a WAB-MT of the WAB node, and the fourth device may receive the fourth information by receiving the fourth information via a RRC signaling. In some embodiments, the third device may be a WAB-NT of the WAB node, and the fourth device may receive the fourth information by receiving the fourth information via a Xn signaling.

At block 1120, a fourth device may perform the flow control based on the fourth information.

In some embodiments, the fourth device may further transmit, to the third device, fifth information comprising at least one of the following: an identity of a second cell in a set of second cells scheduled by the third device, or maximum data volume for the first cell.

With the method 1100, a parent node of a WAB node may perform a flow control for the WAB node based on assistance information received from the WAB node.

It is to be understood that operations of the methods 800 to 1100 correspond to the processes described in connection with FIGs. 2 to 7, and thus other details are not repeated here for conciseness.

EXAMPLE IMPLEMENTATION OF DEVICES

FIG. 12 is a simplified block diagram of a device 1200 that is suitable for implementing embodiments of the present disclosure. The device 1200 can be considered as a further example implementation of the WAB node 120 or the WAB-MT 121 or the WAB-NT 122 or the RAN device 130 or the CN device 140 as shown in FIG. 1. Accordingly, the device 1200 can be implemented at or as at least a part of the WAB node 120 or the WAB-MT 121 or the WAB-NT 122 or the RAN device 130 or the CN device 140.

As shown, the device 1200 includes a processor 1210, a memory 1220 coupled to the processor 1210, a suitable transceiver 1240 coupled to the processor 1210, and a communication interface coupled to the transceiver 1240. The memory 1210 stores at least a part of a program 1230. The transceiver 1240 may be for bidirectional communications or a unidirectional communication based on requirements. The transceiver 1240 may include at least one of a transmitter 1242 or a receiver 1244. The transmitter 1242 and the receiver 1244 may be functional modules or physical entities. The transceiver 1240 has at least one antenna to facilitate communication, though in practice an Access Node mentioned in this application may have several ones. The communication interface may represent any interface that is necessary for communication with other network elements, such as X2/Xn interface for bidirectional communications between eNBs/gNBs, S1/NG interface for communication between a mobility management entity (MME) /access and mobility management function (AMF) /SGW/UPF and the eNB/gNB, Un interface for communication between the eNB/gNB and a relay node (RN) , or Uu interface for communication between the eNB/gNB and a terminal device.

The program 1230 is assumed to include program instructions that, when executed by the associated processor 1210, enable the device 1200 to operate in accordance with the embodiments of the present disclosure, as discussed herein with reference to FIGs. 1 to 11. The embodiments herein may be implemented by computer software executable by the processor 1210 of the device 1200, or by hardware, or by a combination of software and hardware. The processor 1210 may be configured to implement various embodiments of the present disclosure. Furthermore, a combination of the processor 1210 and memory 1220 may form processing means 1250 adapted to implement various embodiments of the present disclosure.

The memory 1220 may be of any type suitable to the local technical network and may be implemented using any suitable data storage technology, such as a non-transitory computer readable storage medium, semiconductor based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory, as non-limiting examples. While only one memory 1220 is shown in the device 1200, there may be several physically distinct memory modules in the device 1200. The processor 1210 may be of any type suitable to the local technical network, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples. The device 1200 may have multiple processors, such as an application specific integrated circuit chip that is slaved in time to a clock which synchronizes the main processor.

In some embodiments, a first device comprises a circuitry configured to: determine that a condition for transmitting first information of flow control for WAB is fulfilled; and transmit, to a second device via at least one of downlink control information, a MAC CE, a MAC subheader or a control PDU, the first information of flow control comprising at least one of the following: an identity of a group or information of a granularity, information of a buffer size, information of a direction of a traffic, or information of a congestion.

In some embodiments, a second device comprises a circuitry configured to: receive, from a first device via at least one of downlink control information, a MAC CE, a MAC subheader or a control PDU, first information of flow control for WAB comprising at least one of the following: an identity of a group or information of a granularity, information of a buffer size, information of a direction of a traffic, or information of a congestion; and perform the flow control based on the first information.

In some embodiments, a third device comprises a circuitry configured to: transmit, to a fourth device, fourth information assistant for flow control for WAB, the fourth information comprising at least one of the following: an identity of a first cell in a set of first cells served by the third device, a preferred maximum throughput for the first cell, a preferred maximum bandwidth for the first cell, or a preferred size threshold for a buffer size.

In some embodiments, a fourth device comprises a circuitry configured to: receive, from a third device, fourth information assistant for flow control for WAB, the fourth information comprising at least one of the following: an identity of a first cell in a set of first cells served by the third device, a preferred maximum throughput for the first cell, a preferred maximum bandwidth for the first cell, or a preferred size threshold for a buffer size; and perform the flow control based on the fourth information.

The term ‘circuitry’ used herein may refer to hardware circuits and/or combinations of hardware circuits and software. For example, the circuitry may be a combination of analog and/or digital hardware circuits with software/firmware. As a further example, the circuitry may be any portions of hardware processors with software including digital signal processor (s) , software, and memory (ies) that work together to cause an apparatus, such as a terminal device or a network device, to perform various functions. In a still further example, the circuitry may be hardware circuits and or processors, such as a microprocessor or a portion of a microprocessor, that requires software/firmware for operation, but the software may not be present when it is not needed for operation. As used herein, the term circuitry also covers an implementation of merely a hardware circuit or processor (s) or a portion of a hardware circuit or processor (s) and its (or their) accompanying software and/or firmware.

Generally, various embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device. While various aspects of embodiments of the present disclosure are illustrated and described as block diagrams, flowcharts, or using some other pictorial representation, it will be appreciated that the blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer readable storage medium. The computer program product includes computer-executable instructions, such as those included in program modules, being executed in a device on a target real or virtual processor, to carry out the process or method as described above with reference to FIGs. 1 to 11. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, or the like that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split between program modules as desired in various embodiments. Machine-executable instructions for program modules may be executed within a local or distributed device. In a distributed device, program modules may be located in both local and remote storage media.

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

The above program code may be embodied on a machine readable medium, which may be any tangible medium that may contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device. The machine readable medium may be a machine readable signal medium or a machine readable storage medium. A machine readable medium may include but not limited to an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of the machine readable storage medium would include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM) , a read-only memory (ROM) , an erasable programmable read-only memory (EPROM or Flash memory) , an optical fiber, a portable compact disc read-only memory (CD-ROM) , an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

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

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

Claims

A first device, comprising:

a processor configured to cause the first device to:

determine that a condition for transmitting first information of flow control for wireless access backhaul (WAB) is fulfilled; and

transmit, to a second device via at least one of downlink control information, a medium access control (MAC) control element (CE) , a MAC subheader or a control protocol data unit (PDU) , the first information of flow control comprising at least one of the following:

an identity of a group or information of a granularity,

information of a buffer size,

information of a direction of a traffic, or

information of a congestion.
The first device of claim 1, wherein the information of the granularity comprises one of the following:

an identity of a logical channel (LCH) ,

an identity of a radio link control (RLC) channel,

an identity of a quality of service (QoS) flow,

an identity of a logical channel group (LCG) ,

an identity of a data radio bearer (DRB) ,

an identity of a cell,

an identity of a cell group,

an identity of a terminal device,

an identity of a granularity in an adaptive layer for WAB, or

a bitmap for a set of LCHs or RLC channels or QoS flows or LCGs or DRBs or cells or cell groups or terminal devices or granularities in adaptive layers for WAB.
The first device of claim 1, wherein the information of the buffer size of the group comprises at least one of the following:

an available or remaining buffer size,

an occupied or predicted buffer size, or

an index of a buffer size level in a buffer size table.
The first device of claim 1, wherein the information of the congestion comprises at least one of the following:

an indication of whether the congestion happens, or

a logical channel (LCH) or a radio link control (RLC) channel or a quality of service (QoS) flow or a logical channel group (LCG) or a data radio bearer (DRB) or a cell or a cell group or a terminal device or a granularity in an adaptive layer for WAB that is congested.
The first device of claim 1, wherein the condition comprises at least one of the following:

second information of a flow control polling is received from the second device; or

a buffer load at the first device is higher than or equal to a load threshold.
The first device of claim 1, wherein the first device is a parent node of a WAB node, and the second device is the WAB node or a mobile termination of the WAB node, the WAB node supporting wireless access to a terminal device and wireless backhaul to the parent node.
The first device of claim 1, wherein the first device is a WAB node or a mobile termination of the WAB node, and the second device is a parent node of the WAB node, the WAB node supporting wireless access to a terminal device and wireless backhaul to the parent node.
The first device of claim 7, wherein the condition comprises at least one of the following:

second information of a flow control polling is received from the second device;

a buffer load at the first device is higher than or equal to a load threshold; or

a request for reporting the first information of flow control is received from a network termination of the WAB node.
The first device of claim 5 or 8, wherein the second information comprises at least one of the following:

an indication of whether the first information is requested;

a logical channel identity (LCID) or extended LCID value for the flow control polling;

a protocol data unit (PDU) type indicating a control PDU for the flow control polling; or

an indication of whether a PDU is a data PDU or control PDU.
The first device of claim 7, wherein the first device is further caused to:

receive, from the second device, a configuration for a transmission of the first information, the configuration comprising at least one of the following:

an indication of whether the transmission of the first information is enabled or disabled,

the identity of the group or the information of the granularity, or

a type of the transmission of the first information.
The first device of claim 7, wherein the first device is further caused to:

receive, from the second device, third information for activating or deactivating a transmission of the first information, the third information comprising at least one of the following:

the identity of the group or the information of the granularity;

an indication of activating or deactivating the transmission of the first information;

a protocol data unit (PDU) type indicating a control PDU for an activation or deactivation of the transmission of the first information; or

an indication of whether a PDU is a data PDU or control PDU.
A second device, comprising:

a processor configured to cause the second device to:

receive, from a first device via at least one of downlink control information, a medium access control (MAC) control element (CE) , a MAC subheader or a control protocol data unit (PDU) , first information of flow control for wireless access backhaul (WAB) comprising at least one of the following:

an identity of a group or information of a granularity,

information of a buffer size,

information of a direction of a traffic, or

information of a congestion; and

perform the flow control based on the first information.
The second device of claim 12, wherein the information of granularity of the group comprises one of the following:

an identity of a logical channel (LCH) ,

an identity of radio link control (RLC) channel,

an identity of a quality of service (QoS) flow,

an identity of a logical channel group (LCG) ,

an identity of a data radio bearer (DRB) ,

an identity of a cell,

an identity of a cell group,

an identity of a terminal device,

an identity of a granularity in an adaptive layer for WAB, or

a bitmap for a set of LCHs or RLC channels or QoS flows or LCGs or DRBs or cells or cell groups or terminal devices or granularities in adaptive layers for WAB.
The second device of claim 12, wherein the information of the buffer size of the group comprises at least one of the following:

an available or remaining buffer size,

an occupied or predicted buffer size, or

an index of a buffer size level in a buffer size table.
The second device of claim 12, wherein the information of the congestion comprises at least one of the following:

an indication of whether the congestion happens, or

a logical channel (LCH) or a radio link control (RLC) channel or a quality of service (QoS) flow or a logical channel group (LCG) or a data radio bearer (DRB) or a cell or a cell group or a terminal device or a granularity in an adaptive layer for WAB that is congested.
The second device of claim 12, wherein the first device is a parent node of a WAB node, and the second device is the WAB node or a mobile termination of the WAB node, the WAB node supporting wireless access to a terminal device and wireless backhaul to the parent node.
The second device of claim 12, wherein the first device is a WAB node or a mobile termination of the WAB node, and the second device is a parent node of the WAB node, the WAB node supporting wireless access to a terminal device and wireless backhaul to the parent node.
The second device of claim 17, wherein the second device is further caused to:

transmit, to the first device, a configuration for a transmission of the first information, the configuration comprising at least one of the following:

an indication of whether the transmission of the first information is enabled or disabled,

the identity of the group or the information of the granularity, or

a type of the transmission of the first information.
The second device of claim 17, wherein the second device is further caused to:

transmit, to the first device, third information for activating or deactivating a transmission of the first information, the third information comprising at least one of the following:

the identity of the group or the information of the granularity;

an indication of activating or deactivating the transmission of the first information;

a protocol data unit (PDU) type indicating a control PDU for an activation or deactivation of the transmission of the first information; or

an indication of whether a PDU is a data PDU or control PDU.
The second device of claim 12, wherein the second device is caused to perform the flow control by:

determining that the congestion happens based on at least one of the following:

an available or remaining buffer size indicated in the first information is smaller than or equal to a size threshold; or

an occupied or predicted buffer size indicated in the first information is greater than or equal to the size threshold.
A third device, comprising:

a processor configured to cause the third device to:

transmit, to a fourth device, fourth information assistant for flow control for wireless access backhaul (WAB) , the fourth information comprising at least one of the following:

an identity of a first cell in a set of first cells served by the third device,

a preferred maximum throughput for the first cell,

a preferred maximum bandwidth for the first cell, or

a preferred size threshold for a buffer size.
The third device of claim 21, wherein the third device is a WAB node, and the fourth device is a parent node of the WAB node, the WAB node supporting wireless access to a terminal device and wireless backhaul to the parent node.
The third device of claim 22, wherein the third device is a mobile termination of the WAB node, and the third device is caused to transmit the fourth information by transmitting the fourth information via a radio resource control (RRC) signaling, or

wherein the third device is a network termination of the WAB node, and the third device is caused to transmit the fourth information by transmitting the fourth information via a Xn signaling.
The third device of claim 21, wherein the third device is further caused to:

receive, from the fourth device, fifth information comprising at least one of the following:

an identity of a second cell in a set of second cells scheduled by the third device, or

maximum data volume for the first cell.
A fourth device, comprising:

a processor configured to cause the fourth device to:

receive, from a third device, fourth information assistant for flow control for wireless access backhaul (WAB) , the fourth information comprising at least one of the following:

an identity of a first cell in a set of first cells served by the third device,

a preferred maximum throughput for the first cell,

a preferred maximum bandwidth for the first cell, or

a preferred size threshold for a buffer size; and

perform the flow control based on the fourth information.
The fourth device of claim 25, wherein the third device is a WAB node, and the fourth device is a parent node of the WAB node, the WAB node supporting wireless access to a terminal device and wireless backhaul to the parent node.
The fourth device of claim 26, wherein the third device is a mobile termination of the WAB node, and the fourth device is caused to receive the fourth information by receiving the fourth information via a radio resource control (RRC) signaling, or

wherein the third device is a network termination of the WAB node, and the fourth device is caused to receive the fourth information by receiving the fourth information via a Xn signaling.
The fourth device of claim 25, wherein the fourth device is caused to perform the flow control by at least one of the following:

in accordance with a determination that the buffer size reported by the third device is greater than or equal to the preferred size threshold, determining that a congestion happens; or

transmitting, to the third device, fifth information comprising at least one of the following:

an identity of a second cell in a set of second cells scheduled by the third device, or

maximum data volume for the first cell.
A method of communication comprising:

determining, at a first device, that a condition for transmitting first information of flow control for wireless access backhaul (WAB) is fulfilled; and

transmitting, to a second device via at least one of downlink control information, a medium access control (MAC) control element (CE) , a MAC subheader or a control protocol data unit (PDU) , the first information of flow control comprising at least one of the following:

an identity of a group or information of a granularity,

information of a buffer size,

information of a direction of a traffic, or

information of a congestion.
A method of communication comprising:

receiving, at a second device and from a first device via at least one of downlink control information, a medium access control (MAC) control element (CE) , a MAC subheader or a control protocol data unit (PDU) , first information of flow control for wireless access backhaul (WAB) comprising at least one of the following:

an identity of a group or information of a granularity,

information of a buffer size,

information of a direction of a traffic, or

information of a congestion; and

performing the flow control based on the first information.
A method of communication comprising:

transmitting, at a third device and to a fourth device, fourth information assistant for flow control for wireless access backhaul (WAB) , the fourth information comprising at least one of the following:

an identity of a first cell in a set of first cells served by the third device,

a preferred maximum throughput for the first cell,

a preferred maximum bandwidth for the first cell, or

a preferred size threshold for a buffer size.
A method of communication comprising:

receiving, at a fourth device and from a third device, fourth information assistant for flow control for wireless access backhaul (WAB) , the fourth information comprising at least one of the following:

an identity of a first cell in a set of first cells served by the third device,

a preferred maximum throughput for the first cell,

a preferred maximum bandwidth for the first cell, or

a preferred size threshold for a buffer size; and

performing the flow control based on the fourth information.