Method and apparatus for radio link flow control

Abstract

The present disclosure relates to methods and apparatus. According to some embodiments of the present disclosure, a method comprises receiving, at a communication device, a configuration message comprising a threshold value for configuring the communication device; transmitting, from the communication device, a congestion indication if an occupied buffer size of the communication device is equal to or greater than the threshold value.

Description

Technical Field

[0001] This disclosure generally relates to wireless communication technologies, and more specifically to radio link flow control in wireless communication systems. Background Technology

[0002] A wireless communication system may include a base station (hereinafter referred to as a "BS") capable of communicating with user equipment (hereinafter referred to as a "UE"). The UE may include mobile devices (e.g., mobile phones, tablets, laptops, Internet of Things (IoT) devices, etc.). The quality of the communication link or channel between the BS and the UE may be degraded due to various factors, such as, but not limited to, obstructions from buildings, relatively long distances between the BS and the UE, etc. One of several solutions to this problem may include deploying relay nodes (hereinafter referred to as "RNs") in the wireless communication system to enhance and / or extend the coverage of the BS, as disclosed in the 3rd Generation Partnership Project (3GPP).

[0003] A BS that communicates with a UE via one or more RNs can be called a donor BS. These RNs, together with the donor BS, can form a backhaul link that allows the UE to reach the donor BS via one or more RNs. Signals from the UE can also be easily transmitted directly from one RN to the donor BS. An integrated access and backhaul (IAB) architecture, which can evolve from RN deployments in 3GPP, is under development to support multi-hop relays in new radio (NR) communication networks.

[0004] However, RNs may experience congestion under certain circumstances, and therefore a new solution is needed to indicate and control congestion in communication networks. Summary of the Invention

[0005] Some embodiments of this disclosure provide a method comprising: receiving at a communication device a configuration message containing a threshold for configuring the communication device; and transmitting a congestion indication from the communication device if the size of the occupied buffer of the communication device is equal to or greater than the threshold.

[0006] Another embodiment of this disclosure provides a method comprising: receiving a congestion indication from a communication device via a message in a media access control (MAC) unit or an adaptation layer.

[0007] Another embodiment of this disclosure provides an apparatus. According to some embodiments of this disclosure, the apparatus includes: at least one non-transitory computer-readable medium having computer-executable instructions stored therein; at least one receiving circuitry; at least one transmitting circuitry; and at least one processor coupled to the at least one non-transitory computer-readable medium, the at least one receiving circuitry, and the at least one transmitting circuitry, wherein the at least one non-transitory computer-readable medium and the computer-executable instructions are configured to use the at least one processor to cause the apparatus to perform a method according to some embodiments of this disclosure. Attached Figure Description

[0008] In order to describe the advantages and features of this disclosure, the description of this disclosure is presented with reference to specific embodiments thereof, which are illustrated in the accompanying drawings. These drawings depict only exemplary embodiments of this disclosure and are therefore not to be considered as limiting its scope.

[0009] Figure 1 Illustrative wireless communication systems according to some embodiments of this disclosure;

[0010] Figure 2 Illustrative wireless communication systems according to some embodiments of this disclosure;

[0011] Figure 3 Illustrative wireless communication systems according to some embodiments of this disclosure;

[0012] Figure 4 Illustrative wireless communication systems according to some embodiments of this disclosure;

[0013] Figure 5 Illustrative wireless communication systems according to some embodiments of this disclosure;

[0014] Figure 6 This describes an exemplary method for congestion indication according to some embodiments of the present disclosure;

[0015] Figure 7A This describes an exemplary MAC control element according to some embodiments of the present disclosure;

[0016] Figure 7B This describes an exemplary MAC control element according to some embodiments of the present disclosure;

[0017] Figure 7C This describes an exemplary MAC control element according to some embodiments of the present disclosure;

[0018] Figure 7D Explaining exemplary MAC control elements according to some embodiments of this disclosure; and

[0019] Figure 8 Example block diagrams illustrating devices according to some embodiments of the present disclosure. Detailed Implementation

[0020] The detailed description of the accompanying drawings is intended as a description of preferred embodiments of the present disclosure and is not intended to represent the only form in which the present disclosure may be practiced. It should be understood that the same or equivalent functionality may be achieved through different embodiments intended to be covered within the spirit and scope of the present disclosure.

[0021] Figure 1 This invention describes a wireless communication system 100 according to some embodiments of the present disclosure.

[0022] refer to Figure 1 The wireless communication system 100 may include some nodes (e.g., BS 110 and RN 120) and some UEs (e.g., UE 130A and UE 130B). Although for simplicity... Figure 1 Only two nodes are described herein, but considering some other embodiments of this disclosure, the wireless communication system 100 may also include more or fewer nodes. Although for simplicity... Figure 1 Only two UEs are described in this disclosure, but it is also considered that in some other embodiments of this disclosure, the wireless communication system 100 may include more or fewer UEs.

[0023] The BS 110, communicating with the core network (CN) 150, can operate or function under the control of the Mobility Management Entity (MME) 140. The core network may include a Home Subscriber Server (HSS) communicatively coupled to the MME. Figure 1 (Not specified in the text). BS 110 may operate based on, for example, standard protocols such as Long Term Evolution (LTE), Advanced LTE (LTE-A), New Radio (NR), or (some) other suitable protocols. For example, BS 110 may include an eNB or gNB and may define one or more cells (e.g., cell 111). RN 120 may include a relay node or an Integrated Access and Backhaul Node (IAB node). UE 130A may include, for example, but not limited to, computing devices, wearable devices, mobile devices, IoT devices, etc. UE 130B may include devices that are the same as or similar to UE 130A. UE 130B may also include devices that are different from UE 130A. Those skilled in the art will understand that the terminology described in this disclosure may change as technology develops and advances, but this should not affect or limit the principles and spirit of this disclosure.

[0024] BS 110 (or donor BS) can establish radio connections with UE 130B and RN 120 via access link (AL) and backhaul link (BL) based on layers 1 (physical layer) to 3 (radio resource control (RRC) layer) of the protocol.

[0025] In some embodiments of this disclosure, RN 120 may establish a radio connection with UE 130A via RN access link (AL1) based on protocol layers 1 to 3. In some other embodiments of this disclosure, RN 120 may establish a radio connection with UE 130A via AL1 based on protocol layers 1 to 2.

[0026] Although for the sake of simplicity, Figure 1 This only shows the donor BS 110 connected to a single UE, but consider that the donor BS 110 can provide or establish connections with multiple UEs. Similarly, although for simplicity, Figure 1 This only shows that the RN 120 is connected to a single UE, but it is worth considering that the RN 120 can also provide or establish connections with multiple UEs.

[0027] (Several) The deployment of the RN helps to enhance and / or extend the coverage of the BS through backhaul links. The Evolved Universal Terrestrial Radio Access Network (E-UTRAN) supports relaying by allowing the RN to wirelessly connect to the eNB serving the RN (referred to as the donor eNB (DeNB)) via a modified version of the Evolved Universal Terrestrial Radio Access (E-UTRA) radio interface (i.e., BL, also known as the Un interface). The radio interface that provides the radio protocol connection between the RN and the UE is called the Uu interface. The relay functionality and the use of RN / DeNB entities in the network are transparent to the operation of the connected UEs.

[0028] As mentioned above, 3GPP is envisioning an IAB architecture for supporting multi-hop relay in 5G (NR) communication networks. In other words, an IAB node may hop over one or more IAB nodes before reaching the IAB donor. Single-hop can be considered a special case of multi-hop. Multi-hop backhaul is relatively advantageous because it provides a relatively larger coverage extension compared to single-hop backhaul. In relatively high-frequency radio communication systems (e.g., radio signals transmitted in bands above 6 GHz), relatively narrow or small signal coverage areas can benefit from multi-hop backhaul technology. Multi-hop backhaul further enables backhauling around obstacles (e.g., buildings in an urban environment for cluttered deployments).

[0029] The maximum number of hops in an RN deployment can depend on various factors, such as, but not limited to, frequency, cell density, propagation environment, traffic load, or other factors. These factors are expected to change over time. Therefore, from a network architecture perspective, it is desirable to ensure flexibility in hop counting. On the other hand, as the number of hops increases, scalability issues may arise. For example, performance may degrade or network load may increase to unacceptable levels.

[0030] Figure 2 This invention describes a wireless communication system 200 according to some embodiments of the present disclosure.

[0031] refer to Figure 2 The wireless communication system 200 may include donor nodes (e.g., IAB donor 210), some IAB nodes (e.g., IAB node 220A, IAB node 220B, IAB node 220C, and IAB node 220D), and some UEs (e.g., UE 230A and UE 230B). Although for simplicity... Figure 2 This disclosure only describes one donor node, but considering some other embodiments of this disclosure, the wireless communication system 200 may include (a number of) more donor nodes. Similarly, although for simplicity, Figure 2 Only four IAB nodes are described herein, but considering some other embodiments of this disclosure, the wireless communication system 200 may include more or fewer IAB nodes. Although for simplicity... Figure 2 Only two UEs are described in this disclosure, but considering some other embodiments of this disclosure, the wireless communication system 200 may include more or fewer UEs.

[0032] IAB node 220A can be directly connected to IAB donor 210. IAB node 220B can reach IAB donor 210 by bypassing IAB node 220A. IAB node 220A is the parent IAB node of IAB node 220B. In other words, IAB node 220B can be a child IAB node of IAB node 220A.

[0033] IAB nodes 220C and 220D can reach IAB donor 210 by skipping IAB nodes 220B and 220A. IAB nodes 220A and 220B can be upstream IAB nodes of IAB nodes 220C and 220D, and IAB node 220B can be the parent IAB node of IAB nodes 220C and 220D. IAB nodes 220B, 220C, and 220D can be downstream IAB nodes of IAB node 220A.

[0034] UE 230A can be directly connected to IAB node 220C, and UE 230B can be directly connected to IAB node 220B. In other words, UE 230A and UE 230B can be served by IAB node 220C and IAB node 220B, respectively. IAB node 220C, IAB node 220D, UE 230A, and UE 230B can be downstream nodes of IAB node 220B. IAB node 220C, IAB node 220D, and UE 230B can be child nodes of IAB node 220B. The radio links between IAB node 220B and IAB node 220C, between IAB node 220B and IAB node 220D, and between IAB node 220B and UE 230B are referred to as downstream links of IAB node 220B.

[0035] According to some other embodiments of this disclosure, each of IAB node 220A, IAB node 220B, IAB node 220C and IAB node 220D may be directly connected to one or more UEs.

[0036] According to some other embodiments of this disclosure, each of IAB node 220A, IAB node 220B, IAB node 220C and IAB node 220D may be directly connected to one or more IAB nodes.

[0037] Figure 3 This invention describes a wireless communication system 300 according to some embodiments of the present disclosure.

[0038] refer to Figure 3 The wireless communication system 300 may include an IAB donor 310, an IAB node 320A, an IAB node 320B, a UE 330A, a UE 330B, a UE 330C, and a next-generation core (NGC) 350.

[0039] Each of IAB nodes 320A and 320B may include a distributed unit (DU) and a mobile terminal (MT). In the context of this disclosure, the MT refers to the function of the radio interface layer residing in the IAB node to terminate the backhaul Uu interface toward the IAB donor or other IAB nodes. The IAB node may connect to an upstream IAB node or BS (e.g., an IAB donor) via the MT function. The IAB node may connect to the UE and downstream IAB nodes via the DU.

[0040] IAB node 320A can connect to upstream IAB node 320B via MT 322A. IAB node 320A can connect to UE 330A via DU 321A. IAB node 320B can connect to upstream IAB node or IAB donor 310 via MT 322B. IAB node 320B can connect to UE 330B via DU 321B. IAB node 320B can connect to downstream IAB node 320A via DU 321B.

[0041] Still referencing Figure 3 A BS (e.g., IAB donor 310) may contain at least one DU to support the UE and MT of the downstream IAB node. A DU of the BS may support at least one cell. A cell may be supported by only one DU of the BS or by a DU of the IAB node.

[0042] The central unit (CU) 311 contained in the IAB donor 310 controls the DUs of all IAB nodes (e.g., IAB node 320A and IAB node 320B) and the DUs residing in the IAB donor 310. The DUs and CUs of the IAB donor may be located together or in different locations. The DUs and CUs of the IAB donor are connected via an F1 interface. In other words, the F1 interface provides a method for interconnecting the CUs and DUs of the IAB donor. The F1 Application Protocol (F1AP) supports the functionality of the F1 interface through certain F1AP signaling procedures.

[0043] In some embodiments of this disclosure, each of the DUs of IAB donor 310, IAB node 320A, and IAB node 320B may host an adaptation layer, a radio link control (RLC) layer, a media access control (MAC) layer, and a physical layer (PHY). The adaptation layer may be configured by the CU of the BS. The adaptation layer performs a number of functions, including routing and bearer mapping (e.g., mapping of backhaul RLC channels), and may include transport (TX) components and receive (RX) components.

[0044] Return to reference Figure 2 IAB nodes (e.g., IAB node 220A, IAB node 220B, IAB node 220C, and IAB node 220D) may contain corresponding MT and DU ( Figure 2 (not specified in the text), and IAB donor 210 may include at least one DU and CU ( Figure 2 (Not specified in the text).

[0045] Still referencing Figure 2The downlink capacity between IAB node 220A and IAB node 220B may be relatively larger than the downlink capacity between IAB node 220B and each of its child nodes (e.g., IAB node 220C, IAB node 220D, and UE 230B). In this case, the ingress data rate scheduled by IAB node 220A to enter IAB node 220B may be relatively higher than the egress data rate scheduled by IAB node 220B from IAB node 220B to its child nodes. This may lead to downlink data congestion at IAB node 220B, and in some cases, may cause packet retransmissions or even packet dropping. Various flow control techniques have been developed to address this issue. In data communication, flow control can be used to manage the data transmission rate between two nodes to control or mitigate congestion.

[0046] End-to-end follow-control technology can be used to alleviate congestion. In this solution, if congestion occurs at the communication device, the communication device can report its congestion status to the BS to which it is connected. Upon receiving the congestion status report, the BS can alleviate the congestion at the communication device by, for example, allocating more resources to the communication device.

[0047] Hop-by-hop follow-up control techniques can be used to alleviate congestion. In this solution, if congestion occurs at a communication device, the communication device can report the congestion status to its parent node (e.g., another upstream communication device or BS) and its child nodes (e.g., another downstream communication device or UE). Upon receiving the congestion status report, the parent node can attempt to resolve the issue by, for example, transmitting data to the communication device (which is experiencing congestion) at a relatively low data rate or transmitting the received congestion status report to the BS. Upon receiving the congestion status report, the child nodes of the communication device (which is experiencing congestion) can, for example, schedule a relatively fast data egress rate to alleviate or reduce congestion at the communication device (which is experiencing congestion).

[0048] Figure 4 This invention describes a wireless communication system 400 according to some embodiments of the present disclosure.

[0049] exist Figure 4 In this context, communication devices 420A, 420B, 420C, and 420D are accessing BS 410, and UE 430A is connected to communication device 420C, while UE 430B is connected to communication device 420B. For example, communication device 420A can be used as... Figure 2 The IAB node 220A and communication device 420B shown can be used as Figure 2 The IAB node 220B and communication device 420C shown can be used as Figure 2The IAB node 220C and communication device 420D shown can be used as Figure 2 The IAB node 220D shown in the image, and BS 410 can be used as Figure 2 The IAB donor 210 is shown in the image.

[0050] End-to-end follow control techniques can be used to control congestion in the wireless communication system 400. For example, as Figure 4 As shown, when congestion occurs at communication device 420B, communication device 420B can transmit a congestion indication to BS 410. In other words, communication device 420B can transmit the congestion indication directly to BS 410 without relaying it through communication device 420A. Upon receiving the congestion indication, the BS can alleviate the congestion at the communication device by, for example, allocating more resources to the communication device.

[0051] For example, such as Figure 4 As shown, when congestion occurs at communication device 420B towards the downstream child node (i.e., communication device 420C), communication device 420B can directly transmit a congestion indication to BS 410. After receiving the congestion indication from communication device 420B, BS 410 can handle the congestion problem. For example, more resources can be allocated to communication device 420B.

[0052] Figure 5 This describes a wireless communication system 500 according to some embodiments of the present disclosure. Figure 5 In this context, communication devices 520A, 520B, 520C, and 520D are accessing BS 510, and UE 530A is connected to communication device 520C, while UE 530B is connected to communication device 520B. For example, communication device 520A can be used as... Figure 2 The IAB node 220A and communication device 520B shown can be used as Figure 2 The IAB node 220B and communication device 520C shown can be used as Figure 2 The IAB node 220C and communication device 520D shown can be used as Figure 2 The IAB node 220D shown in the image, and BS 510 can be used as Figure 2 The IAB donor 210 is shown in the image.

[0053] Hop-by-hop follow-up control techniques can be used to control congestion in the wireless communication system 500. For example, Figure 5As shown, when congestion occurs at communication device 520B, communication device 520B may transmit a congestion indication to its parent node (e.g., communication device 520A). Communication device 520A may transmit the received congestion indication to BS 510 (indicated by the dashed line). Communication device 520A may not transmit the received congestion indication to BS 510. Communication device 520B may transmit the congestion indication to its child node (e.g., communication device 520C).

[0054] This disclosure presents a technical solution for transmission congestion indication, which can facilitate flow control in next-generation communication systems, such as 5G communication systems. The proposed technical solution can be applied to various flow control techniques, such as the end-to-end and hop-by-hop follow control techniques described above. Further details regarding embodiments of this disclosure will be described below with reference to the accompanying drawings.

[0055] Figure 6 An exemplary method 600 for congestion indication according to some embodiments of the present disclosure is described.

[0056] At step 602, the communication device may include Figure 2 The IAB node 220B shown in the document Figure 4 The communication device 420B shown in the document or Figure 5 The communication device 520B shown herein can receive a configuration message from a BS containing a threshold for triggering a congestion indication report, the BS possibly containing Figure 2 The IAB donor 210 shown in the document Figure 4 The BS 410 or shown in the document Figure 5 The BS 510 shown in the image.

[0057] In some embodiments of this disclosure, thresholds may be configured according to the downstream link of the communication device.

[0058] For example, return to reference Figure 2 IAB node 220B may have three downstream links, such as a radio link between IAB node 220B and IAB node 220C, a radio link between IAB node 220B and IAB node 220D, and a radio link between IAB node 220B and UE 230B. IAB donor 210 may configure a corresponding threshold for each of the three downstream links. A threshold configured for one downstream link may be different from a threshold configured for another downstream link. A threshold configured for one downstream link may be the same as a threshold configured for another downstream link.

[0059] In some embodiments of this disclosure, the threshold can be configured to be applied to all downstream links of the communication device. For example, refer to Figure 2The IAB donor 210 can configure a uniform or identical threshold for all three downstream links of the IAB node 220B.

[0060] refer to Figure 6 At step 604, the communication device may determine whether the size of the communication device's occupied buffer is equal to or greater than a threshold. If it is determined that the size of the communication device's occupied buffer is equal to or greater than the threshold, then at step 606, the communication device may, depending on which flow control technology is used, transmit a congestion indication to the BS, the communication device's parent node, the communication device's child node, both the BS and the communication device's parent node, both the communication device's parent node and the communication device's child node, both the BS and the communication device's child node, or all the BS, the communication device's parent node, and the communication device's child node.

[0061] For example, return to reference Figure 4 The communication device 420B can determine that the size of its occupied buffer is equal to or greater than a threshold configured by the BS 410. Then, the communication device 420B can transmit a congestion indication to the BS 410. In some embodiments of this disclosure, the congestion indication can be transmitted to the BS via RRC signaling or F1AP signaling.

[0062] For example, refer to Figure 5 Communication device 520B can determine that the size of its occupied buffer is equal to or greater than a threshold configured by BS 510. Then, communication device 520B can transmit a congestion indication to its parent node (e.g., communication device 520A). Communication device 520B can also transmit the congestion indication to a child node (e.g., communication device 520C) of communication device 520B that is experiencing congestion.

[0063] In some embodiments of this disclosure, congestion indications may be transmitted to the parent node, child node, or both via messages in the MAC unit or adaptation layer.

[0064] In some embodiments of this disclosure, a congestion indication may be included in the MAC control element (CE) of a MAC Protocol Data Unit (PDU). In these embodiments, information or data may be included in the MAC header of the MAC PDU to indicate the MAC CE containing the congestion indication. For example, the MAC header of the MAC PDU may contain a corresponding field (e.g., a Logical Channel ID (LCID) field) indicating the type of each MAC CE. A dedicated LCID value may be assigned to indicate the MAC CE containing the congestion indication.

[0065] In some embodiments of this disclosure, when a congestion indication is transmitted to a child node via a MAC PDU, the header of the MAC PDU may include a dedicated LCID. In some embodiments of this disclosure, the MAC CE corresponding to the dedicated LCID may be empty. The child node will know which MAC CE is used for the congestion indication based on the dedicated LCID.

[0066] The following will combine Figures 7A to 7D Describe in detail the format of the MAC CE transmitted to the parent node.

[0067] Return to reference Figure 6 In some embodiments of this disclosure, the congestion indication may include the identity of a child node of a communication device experiencing congestion. The node's identity may be the node's cell identity (e.g., Physical Cell Identity (PCI)), the node's DU identity, a Cell Radio Network Temporary Identifier (C-RNTI), or any other ID(s) that can be used to identify the node.

[0068] For example, return to reference Figure 2 IAB node 220B may contain a corresponding buffer for each downstream link. If it is determined that the occupancy of the buffer of the radio link between IAB node 220B and IAB node 220C is equal to or greater than the threshold configured by IAB donor 210, then it can be determined that IAB node 220C is experiencing congestion, and the congestion indication to be transmitted by IAB node 220B may contain the identity of IAB node 220C.

[0069] Similarly, if it is determined that the occupancy of the buffer of the radio link between IAB node 220B and UE 230B is equal to or greater than the threshold configured by IAB donor 210, this indicates that UE 230B is experiencing congestion, and the congestion indication to be transmitted by IAB node 220B may include the identity of UE 230B.

[0070] refer to Figure 6 In some embodiments of this disclosure, the congestion indication may include the size of the occupied buffer of the communication device. In some embodiments, the size of the occupied buffer of the communication device may be the number of bits, bytes, etc., occupied by data in the RLC transmission buffer of the communication device. In some embodiments, the RLC transmission buffer may refer to the RLC transmission buffer in the DU of the communication device.

[0071] For example, return to reference Figure 3 The occupied buffer size of IAB node 320A can include the number of bytes occupied by the data in the RLC transfer buffer of DU321A of IAB node 320A.

[0072] refer to Figure 6In some embodiments of this disclosure, before transmitting the congestion indication at step 606, the communication device may transmit a message containing the total buffer size of the communication device. In some embodiments, the total buffer size of the communication device is transmitted during the setup procedure of the communication device. In some embodiments, the total buffer size of the communication device is included in the capability information element (IE) of the communication device.

[0073] For example, return to reference Figure 4 The communication device 420B can transmit the total buffer size of the communication device 420B to the BS410.

[0074] For example, refer to Figure 5 The communication device 520B can transmit the total buffer size of the communication device 520B to its parent node (e.g., the communication device 520A).

[0075] From a communication device (e.g., Figure 4 Communication device 420B or Figure 5 After the communication device 520B in the middle receives the congestion indication, the BS (e.g., Figure 4 BS 410 in the middle) or the parent node of the communication device (e.g., Figure 5 The remaining buffer size of the communication device (520A) can be determined by subtracting the occupied buffer size of the communication device from the total buffer size of the communication device.

[0076] Knowing the remaining buffer size is advantageous because it indicates whether the buffer at the communication device will overflow, and the BS can determine whether the Quality of Service (QoS) requirements for a given traffic will be met.

[0077] refer to Figure 6 In some embodiments of this disclosure, the communication device may determine the remaining buffer size by subtracting the occupied buffer size of the communication device from the total buffer size of the communication device. In these embodiments, the congestion indication may include the remaining buffer size of the communication device. In these embodiments, it may not be necessary to pre-transmit the total buffer size of the communication device.

[0078] In some embodiments of this disclosure, the total buffer size of the communication device may be the size of the RLC transmission buffer of the communication device. In some embodiments, the RLC transmission buffer may refer to the RLC transmission buffer in the DU of the communication device.

[0079] In some embodiments of this disclosure, the total buffer size of the communication device may be the sum of the size of the RLC transmission buffer and the size of the RLC reception buffer of the communication device. In some embodiments, the RLC transmission buffer may refer to the RLC transmission buffer in the DU of the communication device, and the RLC reception buffer may refer to the RLC reception buffer in the MT of the communication device.

[0080] Still referencing Figure 6 At step 608, the communication device may determine whether the content of the congestion indication has changed. If it is determined that the content of the congestion indication has changed, then at step 612, the communication device may, depending on which flow control technology is used, transmit the congestion indication to the BS, the parent node of the communication device, the child node of the communication device, both the BS and the parent node of the communication device, both the parent node of the communication device and the child node of the communication device, both the BS and the child node of the communication device, or all the BS, the parent node of the communication device, and the child node of the communication device.

[0081] In some embodiments of this disclosure, changes in the content of the congestion indication may include changes in the congestion state of the child nodes of the communication device.

[0082] For example, return to reference Figure 2 If it is determined that the amount of occupancy in the buffer of the radio link between IAB node 220B and IAB node 220C is equal to or greater than the corresponding threshold configured by IAB donor 210, then IAB node 220B may transmit a relatively early congestion indication containing the identity of IAB node 220C.

[0083] After a period of time, the congestion on the radio link between IAB node 220B and IAB node 220C can be resolved. That is, the congestion state of IAB node 220C can change from congested to non-congested. IAB node 220B can then transmit an updated congestion indication.

[0084] In another instance, an earlier congestion indication may not include the identity of IAB node 220C. However, after a period of time, the congestion state of IAB node 220C may change from non-congested to congested. For example, the occupancy of the buffer in the radio link between IAB node 220B and IAB node 220C may now be equal to or greater than the corresponding threshold configured by IAB donor 210. IAB node 220B may then transmit an updated congestion indication.

[0085] refer to Figure 4 The communication device 420B can transmit the updated congestion indication to BS 410.

[0086] refer to Figure 5Communication device 520B can transmit the updated congestion indication to its parent node (e.g., communication device 520A) and / or related child nodes (e.g., communication device 520C).

[0087] refer to Figure 6 In some embodiments of this disclosure, in response to transmitting a congestion indication at step 606, the communication device may start a timer (T1). When timer T1 expires, the communication device may determine whether the congestion at the communication device has been resolved; if not, the communication device may, depending on the flow control technique employed, transmit the congestion indication to the BS, the communication device's parent node, the communication device's child nodes, both the BS and the communication device's parent node, both the communication device's parent node and the communication device's child nodes, both the BS and the communication device's child nodes, or all BS, the communication device's parent node, and the communication device's child nodes. For example, if the size of the communication device's occupied buffer is equal to or greater than a threshold configured by the BS, the communication device may determine that the congestion at the communication device has not been resolved.

[0088] Figures 7A to 7D This describes an instance format of a MAC CE according to an embodiment of the present disclosure.

[0089] As described above, in some embodiments of this disclosure, the congestion indication may include the identity of a child node of the communication device experiencing congestion. In some embodiments of this disclosure, the congestion indication may include buffer size information (e.g., occupied buffer size, remaining buffer size, or both) of the communication device associated with the child node. A MAC CE may be used to carry the congestion indication.

[0090] Although for the sake of simplicity, Figures 7A to 7D The node identity shown contains 8 bits, but considering some other embodiments of this disclosure, the node identity may contain more or fewer bits. Although for simplicity... Figure 7C and 7D The buffer size information contains 4 bits, but considering some other embodiments of this disclosure, the buffer size information may contain more or fewer bits. In some other embodiments of this disclosure, Figures 7A to 7D The instance format of MAC CE shown in the document may be modified or changed with regard.

[0091] Figure 7A This description illustrates an exemplary MAC CE 700A according to some embodiments of the present disclosure. The MAC CE 700A can be used to indicate the identity of only one child node of a communication device experiencing congestion. Specifically, as... Figure 7A As shown, the MAC CE700A is an octet aligned array and may contain field 702A. Therefore, the 8-bit field 702A is used to indicate the node's identity.

[0092] For example, return to reference Figure 5 Communication device 520B may transmit a MAC CE containing the identity of one of its child nodes experiencing congestion (e.g., communication device 520C) to its parent node (e.g., communication device 520A). In cases where there are more than one child node of communication device 520B experiencing congestion, such as UE 530B also experiencing congestion in addition to communication device 520C, communication device 520B may transmit an additional MAC CE containing the identity of UE 530B to communication device 520A in a different MAC PDU.

[0093] Figure 7B An exemplary MAC CE 700B according to some embodiments of this disclosure is described. The MAC CE 700B can be used to indicate the identity of each of the child nodes of a communication device experiencing congestion.

[0094] Specifically, such as Figure 7B As shown in the diagram, the MAC CE 700B is octet aligned and contains 4 bytes. The first, second, third, and fourth bytes in the diagram are referred to as "Oct 1", "Oct 2", "Oct 3", and "Oct 4", respectively.

[0095] The MAC CE 700B may contain fields 704B, 702B-1, 702B-2, 702B-3, and 706B. Field 704B may contain 4 bits, each of fields 702B-1, 702B-2, and 702B-3 may contain 8 bits, and field 706B may contain 4 bits. Therefore, field 702B-1 occupies 4 bits of byte "Oct 1" and 4 bits of byte "Oct 2"; field 702B-2 occupies 4 bits of byte "Oct 2" and 4 bits of byte "Oct 3"; and field 702B-3 occupies 4 bits of byte "Oct 3" and 4 bits of byte "Oct 4".

[0096] Fields 702B-1, 702B-2, and 702B-3 can be used to indicate the corresponding identity of a child node experiencing congestion. Field 704B can be used to indicate the number of node identities included in MAC CE 700B. Field 706B can be reserved for future use and can be set to the value "0". The value of the number of node identities included in MAC CE 700B can be equal to or greater than "0". Figure 7B In this case, the MAC CE 700B contains three node identities, and therefore the 704B field can be set to "0011" (equivalent to the decimal value "3").

[0097] In some embodiments of this disclosure, field 704B may be set to "0000" (equivalent to the decimal value "0"). This indicates that all downstream links of the communication device are not congested. In these embodiments, MAC CE 700B may not contain any node identity. That is, MAC CE 700B may not contain fields 702B-1, 702B-2, and 702B-3.

[0098] Although for the sake of simplicity, Figure 7B The field indicating the number of nodes is shown; that is, field 704B contains 4 bits, but considering some other embodiments of this disclosure, this field may contain more or fewer bits. Although for simplicity... Figure 7B The MAC CE 700B is shown to contain three node identities, but considering some other embodiments of this disclosure, the MAC CE 700B may contain more or fewer node identities. Although for the sake of explanation... Figure 7B The MAC CE 700B is shown to begin with field 704B, followed by fields 702B-1, 702B-2, 702B-3, and 706B. However, in some other embodiments of this application, the MAC CE 700B may contain other formats.

[0099] For example, return to reference Figure 5 If, in addition to communication device 520C, UE 530B and communication device 520D are also experiencing congestion (not shown), then communication device 520B can transmit a MAC CE containing the identity of each of the three child nodes experiencing congestion (i.e., communication device 520C, communication device 520D, and UE 530B) to its parent node (e.g., communication device 520A).

[0100] Figure 7C This describes an exemplary MAC CE 700C according to some embodiments of the present disclosure. Figure 7A Similarly, the MAC CE700C can be used to indicate the identity of only one child node of a communication device experiencing congestion. However, the MAC CE 700C can further include buffer size information of the communication device associated with the identified child node.

[0101] Specifically, such as Figure 7C As shown, the MAC CE 700C is octet aligned and contains 2 bytes. In the diagram, the first and second bytes are referred to as "Oct 1" and "Oct 2" respectively.

[0102] The MAC CE 700C can contain fields 702C, 708C, and 706C. Field 702C can contain 8 bits, field 708C can contain 4 bits, and field 706C can contain 4 bits. Therefore, field 702C occupies all 8 bits of byte "Oct 1"; field 708C occupies 4 bits of byte "Oct 2"; and field 706C occupies 4 bits of byte "Oct 2".

[0103] Field 702C can be used to indicate node identity, field 708C can be used to indicate buffer size information, and field 706C can be reserved for future use and can be set to the value "0".

[0104] The buffer size information may include the occupied buffer size of the communication device associated with the child node, the remaining buffer size of the communication device associated with the child node, or both.

[0105] When the buffer size information includes both the occupied buffer size and the remaining buffer size, field 708C may contain two subfields (not shown). Each of the two subfields may contain 2 bits and can be used to indicate the corresponding of the occupied buffer size and the remaining buffer size. Although for simplicity, each of the two subfields of field 708C contains 2 bits, in some other embodiments of this disclosure, the subfields may contain more or fewer bits.

[0106] although Figure 7C The MAC CE 700C is shown to begin with field 702C, followed by fields 708C and 706C, but according to some other embodiments of this application, the MAC CE 700C may contain several other formats.

[0107] For example, refer to Figure 5 Communication device 520B can transmit a MAC CE containing the identity of one of its child nodes (e.g., communication device 520C) experiencing congestion to its parent node (e.g., communication device 520A). The MAC CE also contains buffer size information for communication device 520B associated with communication device 520C. The buffer size information may include the occupied buffer size of communication device 520B associated with communication device 520C, the remaining buffer size of communication device 520B associated with communication device 520C, or both.

[0108] In the presence of more than one child node of communication device 520B experiencing congestion, such as UE 530B also experiencing congestion in addition to communication device 520C, communication device 520B can transmit an additional MACCE containing the identity of UE 530B to communication device 520A and transmit the corresponding buffer size information in different MAC PDUs.

[0109] Figure 7D This describes an exemplary MAC CE 700D according to some embodiments of the present disclosure. Figure 7B Similarly, the MAC CE700D can be used to indicate the identity of each of the child nodes of a communication device experiencing congestion. However, the MAC CE 700D can further include the corresponding buffer size information associated with each of the child nodes.

[0110] Specifically, such as Figure 7D As shown, the MAC CE 700D is octet aligned and contains 4 bytes. In the diagram, the first, second, third, and fourth bytes are referred to as "Oct 1", "Oct 2", "Oct 3", and "Oct 4", respectively.

[0111] The MAC CE 700D may include fields 704D, 702D-1, 708D-1, 702D-2, 708D-2, and 706D. Field 704D may contain 4 bits, each of fields 702D-1 and 702D-2 may contain 8 bits, each of fields 708D-1 and 708D-2 may contain 4 bits, and field 706D may contain 4 bits. Therefore, field 704D occupies 4 bits of byte "Oct 1"; field 702D-1 occupies 4 bits of byte "Oct 1" and 4 bits of byte "Oct 2"; field 708D-1 occupies 4 bits of byte "Oct 2"; field 702D-2 occupies all 8 bits of byte "Oct 3"; field 708D-2 occupies 4 bits of byte "Oct 4"; and field 706D occupies 4 bits of byte "Oct 4".

[0112] Fields 702D-1 and 702D-2 can be used to indicate the corresponding identity of a child node experiencing congestion; fields 708D-1 and 708D-2 can be used to indicate the corresponding buffer size information associated with the child node; field 704D can be used to indicate the number of node identities included in MAC CE 700D; and field 706D can be reserved for future use and can be set to the value "0". Figure 7D In this case, MAC CE 700D contains two node identities, and therefore the field 704D can be set to "0010" (equivalent to the decimal value "2").

[0113] and Figure 7B Similar to field 704B, field 704D can be set to "0000" (equivalent to the decimal value "0"). This indicates that all downstream links of the communication device are not congested. In these embodiments, MAC CE 700D may not contain any node identity. That is, MAC CE 700D may not contain fields 702D-1 and 702D-2.

[0114] The buffer size information indicated in each of fields 708D-1 and 708D-2 may include the corresponding occupied buffer size, the corresponding remaining buffer size, or both. When the buffer size information includes both the occupied buffer size and the remaining buffer size, ... Figure 7C Similar to field 708C, each of fields 708D-1 and 708D-2 may contain two subfields (not shown), which can be used to indicate the corresponding one of the occupied buffer size and the remaining buffer size.

[0115] Although for the sake of simplicity, Figure 7D The field indicating the number of nodes is shown; that is, field 704D contains 4 bits, but considering some other embodiments of this disclosure, this field may contain more or fewer bits. Although for simplicity... Figure 7D The MAC CE 700D is shown to contain two node identities, but considering some other embodiments in this disclosure, the MAC CE 700D may contain more or fewer node identities. Although Figure 7D The MAC CE 700D is shown to begin with field 704D, followed by fields 702D-1, 708D-1, 702D-2, 708D-2, and 706D, but according to some other embodiments of this application, the MAC CE 700D may contain several other formats.

[0116] For example, return to reference Figure 5Assuming that UE 530B is also experiencing congestion (not shown) in addition to communication device 520C, communication device 520B can transmit a MAC CE containing the identity of each of the two child nodes experiencing congestion (i.e., communication device 520C and UE 530B) to its parent node (e.g., communication device 520A). For example, in the MAC CE, field 704D can be set to "0010", field 702D-1 can contain the identity of communication device 520C, field 708D-1 can contain the buffer size information of communication device 520B associated with communication device 520C, field 702D-2 can contain the identity of UE 530B, field 708D-2 can contain the buffer size information of communication device 520B associated with UE 530B, and field 706D can be set to "0000".

[0117] Figure 8 Example block diagrams illustrating a device 800 according to some embodiments of the present disclosure.

[0118] like Figure 8 As shown, device 800 may include at least one non-transitory computer-readable medium. Figure 8 (Not specified in the text), receiving circuitry 802, transmitting circuitry 804, and processor 806 coupled to the non-transitory computer-readable medium receiving circuitry 802 and transmitting circuitry 804. Figure 8 (Not specified in the text). Device 800 may be a BS, a communication device (e.g., an IAB node), or a UE.

[0119] Although elements such as processor 806, transmission circuitry 804, and receiver circuitry 802 are described in the singular in this figure, plural forms are also contemplated unless explicitly stated otherwise. In some embodiments of this disclosure, receiver circuitry 802 and transmission circuitry 804 are combined into a single device, such as a transceiver. In some embodiments of this disclosure, device 800 may further include input devices, memory, and / or other components.

[0120] In some embodiments of this disclosure, a non-transitory computer-readable medium may store computer-executable instructions thereon to cause a processor to perform the methods relating to a communication apparatus as described above. For example, when executed, the computer-executable instructions cause processor 806 to interact with receiving circuitry system 802 and transmitting circuitry system 804 to perform actions relating to... Figure 2 and 3 The IAB nodes depicted in the document and Figures 4 to 6 The steps of the communication device described in the document.

[0121] In some embodiments of this disclosure, a non-transitory computer-readable medium may store computer-executable instructions thereon to cause a processor to perform the methods regarding the BS as described above. For example, when executed, the computer-executable instructions cause processor 806 to interact with receive circuitry system 802 and transmit circuitry system 804 to perform the methods regarding the BS. Figure 2 and 3 The IAB donors depicted in the text and Figures 4 to 6 The steps of BS described in the document.

[0122] Those skilled in the art will understand that the steps of the methods described in connection with the aspects disclosed herein can be directly embodied in hardware, a software module executed by a processor, or a combination of both. The software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art. Additionally, in some aspects, the steps of the method may reside as one or any combination or set of code and / or instructions on a non-transitory computer-readable medium, which may be incorporated into a computer program product.

[0123] While this disclosure has been described using specific embodiments thereof, it will be apparent to those skilled in the art that many alternatives, modifications, and variations will be readily apparent. For example, various components of the described embodiments may be interchanged, added to, or substituted in other embodiments. Moreover, not all elements in each figure are essential to the operation of the disclosed embodiments. For example, those skilled in the art will be able to make and use the teachings of this disclosure by simply employing the elements of the independent claims. Therefore, the embodiments of this disclosure as set forth herein are intended to be illustrative rather than restrictive. Various changes may be made without departing from the spirit and scope of this disclosure.

[0124] In this document, the term "include / including" or any other variation thereof is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but may also include other elements not expressly listed or inherent to the process, method, article, or apparatus. Elements beginning with "a / an" do not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes said element, unless further constraints are imposed. Furthermore, the term "another" is defined as at least one second or more. As used herein, the terms "having" are defined as "includes".

Claims

1. A method for wireless communication, comprising: During the setup procedure for the integrated access and backhaul IAB node, the total buffer size of the IAB node is transmitted, wherein the total buffer size of the IAB node is included in the capability information element of the IAB node. At the IAB node, a configuration message containing a threshold for configuring the IAB node is received. and If the occupied buffer size of the IAB node is equal to or greater than the threshold, then a congestion indication is transmitted from the IAB node to the parent node of the IAB node, wherein the congestion indication includes the remaining buffer size of the IAB node and is transmitted via message transmission in the adaptation layer of the IAB node.

2. The method of claim 1, wherein the congestion indication is further transmitted to one of the following: a base station and a child node of the IAB node.

3. The method of claim 1, wherein the congestion indication includes the occupied buffer size of the IAB node.

4. The method according to claim 1, wherein the remaining buffer size of the IAB node is determined by subtracting the occupied buffer size of the IAB node from the total buffer size of the IAB node.

5. The method according to claim 1 or 4, wherein the total buffer size is determined by the size of the radio link control (RLC) transmission buffer in the distributed unit of the IAB node or the sum of the size of the RLC transmission buffer in the distributed unit of the IAB node and the size of the RLC receive buffer in the mobile terminal of the IAB node.

6. The method of claim 1, further comprising: If the content of the congestion indication changes, then the congestion indication is transmitted.

7. The method of claim 6, wherein the change in the content of the congestion indication includes a change in the congestion state of the child nodes of the IAB node.

8. A method for wireless communication, comprising: The total buffer size of the IAB node is received from the integrated access and backhaul IAB node during the setup procedure of the IAB node, wherein the total buffer size of the IAB node is included in the capability information element of the IAB node. and A congestion indication is received from the IAB node via a message in the adaptation layer, wherein the congestion indication indicates that the occupied buffer size of the IAB node is equal to or greater than a threshold, and the congestion indication includes the remaining buffer size of the IAB node.

9. The method of claim 8, further comprising receiving an updated congestion indication, the content of which differs from the original congestion indication.

10. The method of claim 9, wherein the difference in the content includes changes in the congestion state of the child nodes of the IAB node.

11. An integrated access and backhaul (IAB) node for wireless communication, comprising: At least one non-transitory computer-readable medium having computer-executable instructions stored thereon; At least one receiving circuit system; At least one transmission circuit system; and At least one processor, coupled to the at least one non-transitory computer-readable medium, the at least one receiving circuitry, and the at least one transmitting circuitry. The at least one non-transitory computer-readable medium and the computer-executable instructions are configured to cause the IAB node to perform the method according to any one of claims 1 to 7 using the at least one processor.

12. An integrated access and backhaul (IAB) node for wireless communication, comprising: At least one non-transitory computer-readable medium having computer-executable instructions stored thereon; At least one receiving circuit system; At least one transmission circuit system; and At least one processor, coupled to the at least one non-transitory computer-readable medium, the at least one receiving circuitry, and the at least one transmitting circuitry. The at least one non-transitory computer-readable medium and the computer-executable instructions are configured to cause the IAB node to perform the method according to any one of claims 8 to 10 using the at least one processor.

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