Method and apparatus for transmitting radio link information

Abstract

The present disclosure relates to methods and devices. According to some embodiments of the present disclosure, a method includes: transmitting radio link information, wherein the radio link information is associated with a backhaul link.

Description

Technical Field

[0001] The present disclosure relates generally to wireless communication techniques, and more particularly, to radio link information transmission in a wireless communication system. Background Art

[0002] A wireless communication system may include a base station (hereinafter referred to as a "BS") that communicates with user equipment (hereinafter referred to as a "UE"). The UE may include a mobile device (e.g., a phone, a tablet, a laptop, an Internet of Things (IoT) device, 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) being blocked by buildings, a relatively long distance between the BS and the UE, etc. One of several solutions to address this problem may include deploying a relay node (hereinafter referred to as a "RN") in the wireless communication system to enhance and / or expand the coverage of the BS, as disclosed in the 3rd Generation Partnership Project (3GPP).

[0003] A BS that communicates with a UE through one or more RNs may be referred to as a donor BS. These RNs together with the donor BS may form a backhaul link that allows the UE to reach the donor BS through one or more RNs. Signals from the UE may also be simply transmitted directly from one RN to the donor BS. An integrated access and backhaul (hereinafter referred to as "IAB") architecture that may evolve from RN deployment in 3GPP is being developed to support multi-hop relaying in new radio (NR) communication networks.

[0004] However, the backhaul link may fail under certain conditions, and thus a new solution is needed to transmit the radio link status. Summary of the invention

[0005] An embodiment of the present disclosure provides a method, which includes: transmitting radio link information, wherein the radio link information is associated with a backhaul link.

[0006] Another embodiment of the present disclosure provides a method, which includes receiving radio link information associated with a backhaul link at an integrated access and backhaul node.

[0007] Another embodiment of the present disclosure provides an apparatus. According to another embodiment of the present disclosure, the apparatus includes: at least one non-transitory computer-readable medium in which computer-executable instructions are stored; at least one receiving circuit system; at least one transmitting circuit system; and at least one processor coupled to the at least one non-transitory computer-readable medium, the at least one receiving circuit system, and the at least one transmitting circuit system, wherein the at least one non-transitory computer-readable medium and the computer-executable instructions are configured to cause the apparatus to perform a method according to an embodiment of the present disclosure with the at least one processor. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] In order to describe the manner in which the advantages and features of the present disclosure can be obtained, the description of the present disclosure is presented by reference to specific embodiments of the present disclosure illustrated in the accompanying drawings. These drawings depict only exemplary embodiments of the present disclosure and therefore should not be considered limiting of its scope.

[0009] Figure 1 An exemplary wireless communication system according to an embodiment of the present disclosure is described;

[0010] Figure 2 An exemplary wireless communication system according to an embodiment of the present disclosure is described;

[0011] Figure 3 An exemplary wireless communication system according to an embodiment of the present disclosure is described;

[0012] Figure 4 A flowchart illustrating an exemplary procedure for transmitting radio link information according to an embodiment of the present disclosure;

[0013] Figure 5A Describe an exemplary MAC control element according to an embodiment of the present disclosure;

[0014] Figure 5B Describe an exemplary MAC control element according to an embodiment of the present disclosure;

[0015] Figure 5C Describing exemplary MAC control elements according to embodiments of the present disclosure; and

[0016] Figure 6 An example block diagram illustrating an apparatus according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0017] The detailed description of the accompanying drawings is intended as a description of the preferred embodiments of the present disclosure and is not intended to represent the only form in which the present disclosure can be practiced. It should be understood that the same or equivalent functions can be achieved by different embodiments that are intended to be included in the spirit and scope of the present disclosure.

[0018] Figure 1 A wireless communication system 100 according to an embodiment of the present disclosure is described.

[0019] 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). Figure 1 Only two nodes are illustrated in FIG. 1 , but it is contemplated that in some other embodiments of the present disclosure, the wireless communication system 100 may also include more or fewer nodes. Figure 1Only two UEs are illustrated in FIG. 1 , but it is contemplated that the wireless communication system 100 may include more or fewer UEs in some other embodiments of the present disclosure.

[0020] BS 110 in communication with a core network (CN) 150 may operate or work under the control of a mobility management entity (MME) 140. The core network may include a home subscriber server (HSS) ( Figure 1 130B may include a device that is the same as or similar to UE 130A. UE 130B may also include a device that is different from UE 130A. Those skilled in the art should understand that as technology develops and advances, the terms described in the present disclosure may change, but should not affect or limit the principles and spirit of the present disclosure.

[0021] BS 110 (or donor BS) may establish radio connections with UE 130B and RN 120 through an access link (AL) and a backhaul link (BL), respectively, based on protocol layer-1 (physical layer) to layer-3 (radio resource control (RRC) layer).

[0022] In some embodiments of the present disclosure, RN 120 may establish a radio connection with UE 130A through RN-Access Link (AL1) based on protocol layers-1 to 3. In some other embodiments of the present disclosure, RN 120 may establish a radio connection with UE 130A through AL1 based on protocol layers-1 to 2.

[0023] Although for simplicity Figure 1 The donor BS 110 is shown only connected to a single UE, but it is contemplated that the donor BS 110 may provide or establish connections with multiple UEs. Similarly, although for simplicity Figure 1 The RN 120 is only shown connected to a single UE, but it is contemplated that the RN 120 may also provide or establish connections with multiple UEs.

[0024] The deployment of RN helps to enhance and / or expand the coverage of BS through backhaul links. The Evolved Universal Terrestrial Radio Access Network (E-UTRAN) supports relaying by enabling RN to wirelessly connect to the eNB serving RN (called donor eNB (DeNB)) via a modified version of the Evolved Universal Terrestrial Radio Access (E-UTRA) radio interface (i.e. BL, also known as Un interface). The radio interface that provides a radio protocol connection between RN and UE is called Uu interface. The relay function and purpose of the RN / DeNB entity in the network are transparent to the operation of the connected UE.

[0025] As mentioned above, 3GPP is envisioning an IAB architecture supporting multi-hop relay for 5G (NR) communication networks. In other words, an IAB node may jump one or more IAB nodes before reaching an IAB donor. A single hop may be considered a special case of a multi-hop. Multi-hop backhaul is relatively beneficial because it provides a relatively larger coverage extension than a single-hop backhaul. In relatively high-frequency radio communication systems (e.g., radio signals transmitted in frequency bands above 6 GHz), relatively narrow or small signal coverage may benefit from multi-hop backhaul technology. Multi-hop backhaul further enables backhaul around obstacles (e.g., buildings in urban environments deployed for clutter).

[0026] The maximum number of jumps in RN deployment may depend on various factors, such as (but not limited to) frequency, cell density, propagation environment, traffic load or other factors. It is expected that these factors will change over time. Therefore, from the perspective of network architecture, it is desirable to ensure the flexibility of jump count. On the other hand, as the number of jumps increases, scalability issues may occur. For example, performance may be degraded and / or network load may increase to an unacceptable level.

[0027] Figure 2 A wireless communication system 200 according to an embodiment of the present disclosure is described.

[0028] refer to Figure 2 , the wireless communication system 200 may include a donor node (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 Only one donor node is illustrated in FIG. 1 , but it is contemplated that in some other embodiments of the present disclosure, the wireless communication system 200 may include more donor nodes. Similarly, although for simplicity in FIG. Figure 2 Only four IAB nodes are illustrated in FIG. 2 , but it is contemplated that the wireless communication system 200 may include more or fewer IAB nodes in some other embodiments of the present disclosure. Figure 2 Only two UEs are illustrated in FIG. 2 , but it is contemplated that the wireless communication system 200 may include more or fewer UEs in some other embodiments of the present disclosure.

[0029] The IAB node 220A and the IAB node 220D may be directly connected to the IAB donor 210. According to some other embodiments of the present disclosure, the IAB node 220A and the IAB node 220D may be connected to different donor nodes.

[0030] IAB node 220C can reach IAB donor 210 by skipping IAB node 220D. IAB node 220D is the father IAB node of IAB node 220C. In other words, IAB node 220C can be the child node of IAB node 220D. IAB node 220B can reach IAB donor 210 by skipping IAB node 220C and IAB node 220D. IAB node 220C and IAB node 220D can be the upstream nodes of IAB node 220B, and IAB node 220C can be the father IAB node of IAB node 220B. In other words, IAB node 220B can be the child node of IAB node 220C. IAB node 220B and IAB node 220C can be the downstream nodes of IAB node 220D. UE 230A can be directly connected to IAB node 220A, and UE 230B can be directly connected to IAB node 220B. In other words, UE 230A and UE 230B may be served by IAB node 220A and IAB node 220B, respectively.

[0031] According to some other embodiments of the present disclosure, each of the IAB node 220A, the IAB node 220B, the IAB node 220C, and the IAB node 220D may be directly connected to one or more UEs.

[0032] According to some other embodiments of the present disclosure, each of the IAB node 220A, the IAB node 220B, the IAB node 220C, and the IAB node 220D may be connected to one or more IAB nodes.

[0033] In a wireless communication system 200 providing multi-hop relay, a wireless backhaul link may fail due to, for example (but not limited to), being blocked by a moving object (e.g., a vehicle), vegetation (caused by seasonal reasons), or a new building (e.g., infrastructure changes). This backhaul link failure may occur on a physically stationary IAB node or a mobile IAB node. Link switching techniques have been developed to solve this problem.

[0034] Assuming that a radio link failure (RLF) occurs on the backhaul link between the IAB donor 210 and the IAB node 220D, the IAB node 220D may establish a connection to another donor node ( Figure 2In other words, the IAB node 220D may switch from the link between the IAB node 220D and the IAB donor 210 to the link between the IAB node 220D and another donor node ( Figure 2 not described in the specification).

[0035] Assuming that RLF occurs on the backhaul link between two IAB nodes (e.g., IAB node 220D and IAB node 220C), IAB node 220C may establish a link to another IAB node (e.g., IAB node 220A). In other words, IAB node 220C may switch from the link between IAB node 220C and IAB donor 220D to the link between IAB node 220C and candidate IAB node 220A.

[0036] Another solution is to perform an alternative route exchange procedure. For example, the IAB donor 210 may configure an alternative route for the IAB node 220C (e.g., alternative route A: IAB donor 210 → IAB node 220A → IAB node 220C, which is Figure 2 In the case where RLF occurs on the backhaul link between the IAB node 220D and the IAB node 220C or between the IAB donor 210 and the IAB node 220D, the IAB node 220C may skip the candidate node selection and directly access the candidate node in the alternative route A (eg, the IAB node 220A).

[0037] In the wireless communication system 200, in order to improve the reliability of data transmission or signaling transmission and to reduce delay, a replication function may be provided. This function is characterized in that a packet and its copy are transmitted through two independent transmission paths respectively. The replication function may be activated or deactivated at the BS side, the IAB node side and / or the UE side.

[0038] Downlink duplication means that the BS can transmit a packet (original packet) and its copy (duplicate packet) to the IAB node through two independent transmission paths, respectively. For example, the IAB donor 210 can transmit the original packet to the IAB node 220C through the IAB node 220A and transmit the duplicate packet to the IAB node 220C through the IAB node 220D. If the IAB node 220C receives one of the original and duplicate packets, it will discard the other.

[0039] On the other hand, uplink duplication means that the IAB node or UE can transmit a packet (original packet) and its copy (duplicate packet) to the BS through two independent transmission paths, respectively. For example, the IAB node 220C can transmit the original packet to the IAB donor 210 through the IAB node 220A and transmit the duplicate packet to the IAB donor 210 through the IAB node 220D. If the IAB donor 210 receives one of the original and duplicate packets, it will discard the other.

[0040] Figure 3 A wireless communication system 300 according to an embodiment of the present disclosure is described.

[0041] 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.

[0042] Each of the IAB node 320A and the IAB node 320B may include a distributed unit (DU) and a mobile terminal (MT). In the context of the present disclosure, MT refers to a function residing in the IAB node that terminates the radio interface layer of the backhaul Uu interface toward the IAB donor or other IAB nodes. The IAB node may be connected to an upstream IAB node or BS (e.g., an IAB donor) via the MT function. The IAB node may be connected to a UE and a downstream IAB node via the DU.

[0043] The IAB node 320A may be connected to an upstream IAB node 320B via a MT 322A function. The IAB node 320A may be connected to a UE 330A via a DU 321A function. The IAB node 320B may be connected to an upstream IAB node or an IAB donor 310 via a MT 322B function. The IAB node 320B may be connected to a UE 330B via a DU 321B function. The IAB node 320B may be connected to a downstream IAB node 320A via a DU 321B function.

[0044] In some embodiments of the present disclosure, Figure 3 The IAB nodes shown in may include layer-2 (L2) IAB nodes.

[0045] Return to reference Figure 2 , the IAB nodes (eg, the IAB node 220A, the IAB node 220B, the IAB node 220C, and the IAB node 220D) may include L2 IAB nodes.

[0046] refer to Figure 3, a BS (e.g., IAB donor 310) may include at least one DU to support UEs and MTs of a downstream IAB node. One DU of a BS may support at least one cell. One cell may be supported by only one DU of a BS or a DU of an IAB node.

[0047] A central unit (CU) 311 included 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 co-located or may be located 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 way to interconnect the CUs and DUs of the IAB donor. The F1 application protocol (F1AP) supports the functionality of the F1 interface through a specific F1AP signaling procedure.

[0048] In some embodiments of the present disclosure, each of the DUs of the IAB donor 310, the IAB node 320A, and the IAB node 320B may host an adaptation layer, a radio link control (RLC) layer, a medium access control (MAC) layer, and a physical layer (PHY). The adaptation layer may be configured by a CU of the BS. The adaptation layer performs many functions including routing and bearer mapping (e.g., backhaul RLC channel mapping), and may include a transmission (TX) component and a reception (RX) portion.

[0049] The TX component of the adaptation layer performs routing and "bearer mapping". The RX component of the adaptation layer performs "bearer demapping". For example, the RX component of the adaptation layer can demap the received packet and find that the demapped packet is destined for another node (target node), such as a downstream node or an upstream node. Then, the RX component of the adaptation layer can forward the received packet, the demapped packet, to the TX component of the adaptation layer. The TX component of the adaptation layer can perform routing and "bearer mapping" on the demapped packet and forward it to the target node.

[0050] As mentioned above, in a wireless communication system supporting multi-hop relay, the backhaul link may fail. Figure 2 , the IAB node 220D will know that RLF occurs on the backhaul link between the IAB donor 210 and the IAB node 220D after, for example, detecting a specific problem in its physical layer. However, the downstream nodes of the IAB node 220D may not be aware of this connection loss and therefore cannot perform timely adjustments, which may cause problems such as service interruption and packet loss at these downstream nodes. Therefore, a procedure for notifying the network of changes in the backhaul link is needed.

[0051] The embodiments of the present disclosure propose a technical solution for transmitting radio link information associated with a radio link, which can at least solve the above-mentioned problems in a new generation communication system such as a 5G communication system. More details about the embodiments of the present disclosure will be described in the following text in conjunction with the accompanying drawings.

[0052] Figure 4 Flowchart illustrating an exemplary procedure 400 for transmitting radio link information according to an embodiment of the present disclosure.

[0053] exist Figure 4 In FIG. 4 , IAB node 420D and IAB node 420C are accessing BS 410. IAB node 420C is a child node of IAB node 420D. In other words, IAB node 420C is accessing BS 410 via IAB node 420D. IAB node 420C and IAB node 420D may include corresponding MT and DU ( Figure 4 ), and BS 410 may include at least one DU and CU ( Figure 4 not specified in the table).

[0054] For example, the IAB node 420C may be used as Figure 2 The IAB node 220C shown in FIG. 4 and the IAB node 420D can be used as Figure 2 The IAB node 220D shown in FIG. 1 and the BS 410 may be used as Figure 2 IAB donor 210 is shown in FIG.

[0055] At step 404, RLF may occur on the radio link between BS 410 and IAB node 420D. In some embodiments, IAB node 420D may detect a problem in its physical layer and may declare RLF on the radio link between BS 410 and IAB node 420D. For example, IAB node 420D may start a synchronization timer after detecting a specific problem in its physical layer, may stop the timer after receiving a specific indication, and may declare RLF after the synchronization timer expires. In some embodiments, the synchronization timer may be timer T310, as defined in 3GPP specification TS 38.331. Expiration of timer T310 indicates that RLF occurs on the radio link between IAB node 420D and its parent node (e.g., BS 410).

[0056] In response to the expiration of the synchronization timer, the IAB node 420D may attempt to restore the failed link. For example, the IAB node 420D may initiate an RRC connection reestablishment procedure, after which a reestablishment start timer (e.g., timer T311 defined in 3GPP specification TS38.331) may be started. After selecting a suitable cell, the IAB node 420D may stop the reestablishment start timer (e.g., timer T311).

[0057] During the reestablishment procedure, a reestablishment request timer (e.g., timer T301 defined in 3GPP specification TS 38.331) may be started when the IAB node 420D transmits an RRC connection reestablishment request message to the selected cell. Upon receiving the RRC connection reestablishment message from the selected cell, the IAB node 420D may stop the reestablishment request timer (e.g., timer T301) and may transmit an RRC reestablishment complete message to the selected cell in response.

[0058] In step 406, the IAB node 420D may transmit radio link information associated with the radio link between the BS 410 and the IAB node 420D to a downstream node of the IAB node 420D (e.g., the IAB node 420C). In some embodiments of the present disclosure, the radio link information may indicate that an RLF has occurred on the radio link between the BS 410 and the IAB node 420D, and an attempt to recover from the RLF is in progress. In some embodiments of the present disclosure, the MT of the IAB node 420D may instruct the DU of the IAB node 420D to transmit the radio link information to a downstream node of the IAB node 420D.

[0059] In some embodiments of the present disclosure, the radio link information may be transmitted in response to the declaration of RLF between the IAB node 420D and the BS 410. In some embodiments of the present disclosure, the radio link information may be transmitted in response to the expiration of a synchronization timer (e.g., timer T310). In some embodiments of the present disclosure, the radio link information may be transmitted in response to the initiation of an RRC connection reestablishment procedure. In some embodiments, the radio link information may be transmitted in response to the start of a reestablishment start timer (e.g., timer T311). In some embodiments of the present disclosure, the radio link information may be transmitted in response to the transmission of an RRC connection reestablishment request message. In some embodiments, the radio link information may be transmitted in response to the start of a reestablishment request timer (e.g., timer T301).

[0060] In some embodiments of the present disclosure, the radio link information may further include a value of a timer. In some other embodiments of the present disclosure, the procedure 400 may include step 402 (indicated as an option by a dashed arrow). In step 402, the BS 410 may transmit an RRC signaling message including the value of the timer to the IAB node 420C.

[0061] In some embodiments of the present disclosure, the radio link information may further include a pause indication. The pause indication may instruct a node (ie, a receiving node) receiving the pause indication to perform a specific operation at the receiving node.

[0062] In some embodiments of the present disclosure, the suspension indication may indicate whether to suspend a timer in the RLC layer (RLC timer) at the receiving node and prevent the RLC timer from starting. The RLC timer may include at least one of the timer t-pollRetransmit, the timer t-reassembly, or the timer t-prohibitStatus defined in the 3GPP specification TS 38.322.

[0063] In some embodiments of the present disclosure, the suspension indication may indicate whether a specific operation in the MAC layer is allowed or prohibited at the receiving node. The operation in the MAC layer may include, for example, at least one of the following: performing a random access (RA) procedure, transmitting a scheduling request (SR), transmitting a buffer status report (BSR), or using a configuration grant. The definitions of SR, BSR, and configuration grant are defined in 3GPP specification TS 38.321.

[0064] In some embodiments of the present disclosure, the pause indication may include a one-bit indication. In some embodiments, the value of the pause indication is "1" which may indicate that the RLF timer at the receiving node should be paused, stopped, or prohibited from starting depending on the state of the RLC timer, and the value of the pause indication is "0" which may indicate that there is no such effect on the RLF layer; or vice versa. In some embodiments, the value of the pause indication is "1" which may indicate that a specific operation in the MAC layer of the receiving node should be prohibited, and the value of the pause indication is "0" which may indicate that there is no such effect on the MAC layer; or vice versa. In some embodiments, the value of the pause indication is "1" which may indicate the above-described effects on both the RLC layer and the MAC layer; and the value of the pause indication is "0" which may indicate that there is no such effect on the RLC layer or the MAC layer; or vice versa.

[0065] In some embodiments of the present disclosure, the radio link information may further include information indicating two nodes between which the radio link is formed. In some embodiments, the radio link information may further include IDs of the two nodes between which the radio link is formed. The ID of the node may be a cell identifier of the node (e.g., a physical cell identifier (PCI)) or an identifier of a DU of the node (e.g., a gNB-DU ID). For example, the radio link information may include an ID of the IAB node 420D and an ID of the BS 410.

[0066] In step 408, in response to receiving the radio link information, the IAB node 420C may perform a specific operation.

[0067] In some embodiments of the present disclosure, the IAB node 420C may forward the received radio link information to its downstream node (if any). Figure 2In response to receiving the radio link information from the IAB node 220D, the IAB node 220C may forward the received radio link information to the IAB node 220B.

[0068] Return to reference Figure 4 In some embodiments of the present disclosure, in response to receiving the radio link information, the IAB node 420C may suspend or stop any running RLC timer and may prevent the RLC timer from starting. The RLC timer may include, for example, at least one of a timer t-pollRetransmit, a timer t-reassembly, or a timer t-prohibitStatus. In some embodiments, in the case where the radio link information includes the suspend indication described above, the IAB node 420C may determine whether to perform the above operation on the RLC timer based on the suspend indication. For example, the IAB node 420C may determine to suspend or stop any running RLC timer and prevent the RLC timer from starting based on the value of the suspend indication being, for example, "1".

[0069] In some embodiments of the present disclosure, in response to receiving the radio link information, the IAB node 420C may prohibit specific operations in the MAC layer. The operations in the MAC layer may include, for example, at least one of the following: executing an RA procedure, transmitting an SR or a BSR, or using a configuration authorization. In some embodiments, in the case where the radio link information includes the above-described pause indication, the IAB node 420C may prohibit the above-mentioned operations in the MAC layer based on the pause indication. For example, the IAB node 420C may prohibit the above-mentioned operations in the MAC layer based on the value of the pause indication being, for example, "1".

[0070] In some embodiments of the present disclosure, in the case where the radio link information includes the value of the timer or the value of the timer is configured by the BS 410 at the IAB node 420C (as described above), the IAB node 420C may start a timer (timer A) according to the value of the timer after receiving the radio link information. Once the timer A expires, the IAB node 420C may perform a reestablishment procedure with a communication node that is not the current serving cell of the IAB node 420C (i.e., the IAB node 420D). In other words, during the cell selection for reestablishment, the current serving cell of the IAB node 420C (i.e., the IAB node 420D) cannot be selected as a suitable cell for reestablishment.

[0071] In some embodiments of the present disclosure, an alternative route may be configured at IAB node 420C. In these embodiments, in response to receiving the radio link information, IAB node 420C may perform an alternative route exchange procedure in the event that the alternative route configured at IAB node 420C does not include two nodes that terminate the radio link, such as IAB node 420D and BS 410. In this case, steps 412 and 414 will be omitted from exemplary procedure 400.

[0072] For example, refer to Figure 2 , the IAB donor 210 may configure an alternative route for the IAB node 220B (eg, an alternative route: IAB donor 210 → IAB node 220A → IAB node 220B, which is Figure 2 The RLF may occur on the radio link between the IAB node 220D and the IAB node 220C. In response to receiving the radio link information from the IAB node 220C, the IAB node 220B may perform an alternative route exchange procedure to access the IAB node 220A in the configured alternative route, because the IAB node 220D and the IAB node 220C are not included in the alternative route of the IAB node 220B.

[0073] Return to reference Figure 4 In some embodiments of the present disclosure, uplink duplication may be configured at the IAB node 420C. In these embodiments, in the case where the uplink duplication is in a deactivated state, the IAB node 420C may activate the uplink duplication in response to receiving the radio link information.

[0074] For example, refer to Figure 2 , uplink replication may be configured and may be in a deactivated state at the IAB node 220C. RLF may occur on the radio link between the IAB node 220D and the IAB donor 210. In response to receiving the radio link information from the IAB node 220D, the IAB node 220C may activate uplink replication so that data may be transmitted to the IAB donor 210 via, for example, the IAB node 220A.

[0075] Return to reference Figure 4 In step 412, the IAB node 420D may transmit radio link information associated with the radio link between the BS 410 and the IAB node 420D to a downstream node of the IAB node 420D (eg, the IAB node 420C).

[0076] In some embodiments of the present disclosure, the radio link information transmitted at step 412 may indicate that the failed radio link has been successfully restored. In these embodiments, the radio link information may be transmitted in response to the reception of an RRC connection reestablishment message or in response to the transmission of an RRC reestablishment complete message.

[0077] In some embodiments of the present disclosure, the radio link information transmitted at step 412 may further include information indicating two nodes between which the radio link is formed. In some embodiments, the radio link information may further include IDs of the two nodes between which the radio link is formed. For example, the radio link information may include an ID of the IAB node 420D and an ID of the BS 410.

[0078] In some embodiments of the present disclosure, the radio link information transmitted at step 412 may indicate that an attempt to recover from RLF at the IAB node 420D has failed. In these embodiments, the radio link information may be transmitted in response to the expiration of a reestablishment start timer (e.g., timer T311) or in response to the expiration of a reestablishment request timer (e.g., timer T301).

[0079] In some embodiments of the present disclosure, the radio link information transmitted at step 412 may further include information indicating two nodes between which the radio link is formed. In some embodiments, the radio link information may further include IDs of the two nodes between which the radio link is formed. For example, the radio link information may include an ID of the IAB node 420D and an ID of the BS 410.

[0080] In step 414, in response to receiving the radio link information, the IAB node 420C may perform a specific operation.

[0081] In some embodiments of the present disclosure, in the case where timer A is started, the IAB node 420D may stop timer A at step 414 .

[0082] In some embodiments of the present disclosure, in the event that the received radio link information indicates a successful RLF recovery, the IAB node 420C may allow an RLC timer to be started and may additionally resume a suspended RLC timer of the IAB node 420C, if any. The RLC timer may include, for example, at least one of a timer t-pollRetransmit, a timer t-reassembly, or a timer t-prohibitStatus.

[0083] In some embodiments of the present disclosure, upon receiving radio link information indicating successful RLF recovery, the IAB node 420C may allow specific operations in the MAC layer. The operations in the MAC layer may include, for example, at least one of: performing an RA procedure, transmitting an SR or BSR, or using a configuration authorization.

[0084] In some embodiments of the present disclosure, in the event that the received radio link information indicates a successful RLF recovery and uplink duplication is activated at the IAB node 420C, the IAB node 420C may deactivate the uplink duplication at the IAB node 420C.

[0085] In some embodiments of the present disclosure, in the case where radio link information indicating RLF recovery failure is received, the IAB node 420C may perform an alternative route exchange procedure or a re-establishment procedure. For example, in some embodiments, in the case where an alternative route is configured at the IAB node 420C and does not include two nodes (e.g., the IAB node 420D and the BS 410) between which a radio link is formed, the IAB node 420C may perform an alternative route exchange procedure. In some embodiments, the IAB node 420C may perform a re-establishment procedure with a communication node that is not the current serving cell of the IAB node 420C (i.e., the IAB node 420D). In other words, during cell selection, the current serving cell of the IAB node 420C (i.e., the IAB node 420D) cannot be selected as a suitable node for re-establishment.

[0086] Although the exemplary procedure 400 described herein may include steps 402, 404, 406, 408, 412, and 414, those skilled in the art will appreciate that some of the above steps in the exemplary procedure may be optionally omitted without departing from the spirit and scope of the present disclosure. For example, in some embodiments, steps 402 to 408 may be omitted so that the IAB node 420D transmits the radio link information only when the RLF recovery failure occurs, as described above.

[0087] In some embodiments of the present disclosure, the radio link information mentioned above may be transmitted via a MAC message. In some embodiments, the radio link information may be included in a MAC control element (CE) of a MAC protocol data unit (PDU), and a dedicated type may be included in a MAC header of the MAC PDU to indicate a MAC CE containing radio link information. For example, in the MAC header of the MAC PDU, there may be 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 a MAC CE containing radio link information. The format of this MAC CE will be described in detail in the following text.

[0088] Figures 5A to 5C An exemplary format of a MAC CE according to an embodiment of the present disclosure is described.

[0089] Figure 5A An exemplary MAC CE 500A according to an embodiment of the present disclosure is illustrated; MAC CE 500A may include field 502A, field 504A-1, field 504A-2, field 504A-3, field 504A-4, field 504A-5, and field 504A-6. Field 502A may include two bits, and each of fields 504A-1 to 504A-6 may include one bit. Thus, MAC CE 500A may include eight bits (i.e., 1 byte) and is therefore eight-bit aligned. Although for simplicity, Figure 5A MAC CE 500A is shown starting with field 502A, but it is contemplated that field 502A may be located anywhere in MAC CE 500A.

[0090] As mentioned above about Figure 4 Description, the radio link information may indicate the current state of the radio link, namely: state (1): a failure has occurred on the radio link and an attempt to recover from the failure is in progress; state (2): the radio link has been successfully recovered; or state (3): an attempt to recover from RLF has failed. Return to reference Figure 5A , field 502A may be used to indicate radio link information. For example, the values ​​of field 502A are "00", "01", and "10" may represent state (1), state (2), and state (3), respectively. Other variations may be readily envisioned by those skilled in the art. Fields 504A-1 to 504A-6 may be reserved for future use and may be set to a value of "0".

[0091] In some embodiments of the present disclosure, the radio link information may further include additional assistance information which may be indicated by at least one of fields 504A-1 to 504A-6. Fields not used to include additional assistance information may be reserved for future use and may be set to a value of "0".

[0092] For example, in some embodiments, the radio link information may further include a value of a timer, and at least one of fields 504A-1 to 504A-6 may be used to indicate the value of the timer. For example, fields 504A-1 and 504A-2 may be used to indicate the value of the timer.

[0093] In some embodiments, the radio link information may further include a pause indication, and at least one of fields 504A-1 to 504A-6 may be used to indicate the pause indication. For example, in the case where the pause indication is a one-bit indication, field 504A-6 may be used to indicate the pause indication.

[0094] In some embodiments, the radio link information may further include both the value of the timer and the pause indication, and the corresponding fields of fields 504A-1 to 504A-6 may be used to indicate the value of the timer and the pause indication, respectively. For example, field 504A-1 may be used to indicate the value of the timer, and field 504A-2 may be used to indicate the pause indication.

[0095] In some embodiments of the present disclosure, the radio link information may further include information indicating two nodes between which the radio link is formed. In some embodiments, the radio link information may further include IDs of the two nodes between which the radio link is formed. For example, referring to Figure 4 , the radio link information may include the ID of the IAB node 420D and the ID of the BS 410. Figure 5B An exemplary MAC CE 500B applicable to the above-described embodiment will be described.

[0096] refer to Figure 5B , MAC CE 500B is octet aligned and specifically includes 3 bytes, the first, second and third bytes are referred to as "Oct 1", "Oct 2" and "Oct 3" in the figure, respectively. MAC CE 500B may include field 502B, field 504B-1, field 504B-2, field 506B-1 and field 506B-2. Field 502B may include two bits, each of field 504B-1 and field 504B-2 may include one bit, and each of field 506B-1 and field 506B-2 may include 10 bits. Therefore, field 506B-1 occupies 4 bits of byte "Oct 1" and 6 bits of byte "Oct 2"; field 506B-2 occupies 2 bits of byte "Oct 2" and all 8 bits of byte "Oct 3".

[0097] Field 502B may be used to communicate with the above description regarding Figure 5A A similar manner is described to indicate the current state of the radio link. Field 506B-1 and field 506B-2 may be used to indicate the IDs of the two nodes between which the radio link is formed, respectively. Field 504B-1 and field 504B-2 may be reserved for future use and may be set to a value of "0".

[0098] In some embodiments of the present disclosure, the radio link information may further include additional assistance information that may be carried by at least one of field 504B-1 and field 504B-2. Fields not used to indicate additional assistance information may be reserved for future use and may be set to a value of "0".

[0099] For example, in some embodiments, the radio link information may further include a value of a timer, and at least one of the field 504B-1 and the field 504B-2 may be used to indicate the value of the timer. For example, the field 504B-1 may be used to indicate the value of the timer.

[0100] In some embodiments, the radio link information may further include a pause indication, and at least one of field 504B-1 and field 504B-2 may be used to indicate the pause indication. For example, in the case where the pause indication is a one-bit indication, field 504B-2 may be used to indicate the pause indication.

[0101] In some embodiments, the radio link information may further include both the value of the timer and the pause indication. In these embodiments, one of field 504B-1 and field 504B-2 may be used to indicate the value of the timer, and the other may be used to indicate the pause indication.

[0102] Although for simplicity, Figure 5B MAC CE 500B is shown starting with field 502B, followed by fields 504B-1, 504B-2, 506B-1, and 506B-2, but various modifications of this arrangement should be readily apparent to those skilled in the art. For example, MAC CE 500B may start with field 502B, followed by 506B-1, 506B-2, 504B-1, and 504B-2.

[0103] Furthermore, although for simplicity, Figure 5B The node ID is shown to include 10 bits, but it is contemplated that the node ID may include more or less than 10 bits. For example, the node ID may include 32 bits. Those skilled in the art will readily appreciate corresponding modifications to the exemplary formats described above.

[0104] refer to Figure 4 As mentioned above, in some embodiments of the present disclosure, the IAB node 420D transmits the radio link information only when a RLF recovery failure occurs. In these embodiments, the radio link information may be implemented by a dedicated type in the MAC header of the MAC PDU. For example, a dedicated LCID value may be specified in the MAC header to indicate a RLF recovery failure. The MAC PDU may or may not include a MAC CE corresponding to a dedicated LCID depending on the presence of additional assistance information, as will be described below.

[0105] For example, in some embodiments, the radio link information may further include additional auxiliary information, such as information indicating two nodes between which the radio link is formed. Figure 5C An exemplary MAC CE 500C applicable to the above-described embodiment will be described.

[0106] refer to Figure 5C , MAC CE 500C is octet aligned and specifically includes 3 bytes, the first, second and third bytes are referred to as "Oct 1", "Oct 2" and "Oct 3" in the figure, respectively. MAC CE 500C may include fields field 506C-1, field 506C-2, field 504C-1, field 504C-2, field 504C-3 and field 504C-4. Each of field 506C-1 and field 506C-2 may include 10 bits, and each of field 504C-1, field 504C-2, field 504C-3 and field 504C-4 may include one bit. Therefore, field 506C-1 occupies all 8 bits of byte "Oct 3" and 2 bits of byte "Oct 2"; field 506C-2 occupies 6 bits of byte "Oct 2" and 4 bits of byte "Oct 3".

[0107] Field 506C-1 and field 506C-2 may be used to indicate the IDs of two nodes between which a radio link is formed, respectively.Field 504C-1, field 504C-2, field 504C-3, and field 504C-4 may be reserved for future use and may be set to a value of "0".

[0108] Although for simplicity, Figure 5C MAC CE 500C is shown starting with field 502C-1, followed by fields 506C-2, 504C-1, 504C-2, 504C-3, and 504C-4, but various modifications of this arrangement should be readily apparent to those skilled in the art. For example, MAC CE 500C may start with field 504C-1, followed by 504C-2, 504C-3, 504C-4, 506C-1, and 506C-2.

[0109] Furthermore, although for simplicity, Figure 5C The node ID is shown to include 10 bits, but it is contemplated that the node ID may include more or less than 10 bits. For example, the node ID may include 32 bits. Those skilled in the art will readily appreciate corresponding modifications to the exemplary formats described above.

[0110] In some embodiments of the present disclosure, the above-mentioned radio link information may be transmitted via an adaptation layer message.

[0111] In some embodiments, as described above with respect to Figure 4In the embodiment described above, the radio link information may indicate the current state of the radio link, namely: state (1): a failure has occurred on the radio link and an attempt to recover from the failure is in progress; state (2): the radio link has been successfully recovered; or state (3): an attempt to recover from RLF has failed. In these embodiments, the adaptation layer message may include a two-bit state indication to indicate the current state of the radio link. For example, the values ​​of the two-bit state indication are "00", "01", and "10", which may represent state (1), state (2), and state (3), respectively. Those skilled in the art may easily conceive of other variations.

[0112] In some embodiments, as described above with respect to Figure 4 Description, radio link information may be transmitted only when RLF recovery failure occurs. In these embodiments, the adaptation layer message may include a one-bit status indication to indicate RLF recovery failure.

[0113] In the above embodiment, the radio link information may further include additional auxiliary information, such as information indicating two nodes between which the radio link is formed. In this case, information indicating the two nodes (such as the IDs of the two nodes) should also be included in the adaptation layer message.

[0114] Figure 6 An example block diagram illustrating a device 600 according to an embodiment of the present disclosure.

[0115] like Figure 6 As shown in FIG. 6 , the apparatus 600 may include at least one non-transitory computer-readable medium ( Figure 6 ), receiving circuit system 602, transmitting circuit system 604 and coupling to the non-transitory computer-readable medium ( Figure 6 ), a processor 606 of a receiving circuit system 602 and a transmitting circuit system 604. Apparatus 600 may be a BS or an IAB node.

[0116] Although elements such as processor 606, transmit circuit system 604, and receive circuit system 602 are described in singular form in this figure, plural form is contemplated unless limitation to singular form is explicitly stated. In some embodiments of the present disclosure, receive circuit system 602 and transmit circuit system 604 are combined into a single device, such as a transceiver. In a specific embodiment of the present disclosure, apparatus 600 may further include an input device, a memory, and / or other components.

[0117] In some embodiments of the present disclosure, a non-transitory computer-readable medium may store thereon computer-executable instructions that cause a processor to implement the method for the IAB node described above. For example, when the computer-executable instructions are executed, the processor 606 interacts with the receiving circuit system 602 and the transmitting circuit system 604 to perform the method for transmitting the IAB node described above. Figures 2 to 4 The steps of the IAB node are depicted in FIG.

[0118] In some embodiments of the present disclosure, a non-transitory computer-readable medium may store thereon computer-executable instructions that cause a processor to implement the method for the BS described above. For example, when the computer-executable instructions are executed, the processor 606 interacts with the receiving circuit system 602 and the transmitting circuit system 604 to perform the method for transmitting the BS in the above-described manner. Figures 2 to 4 The steps of BS are depicted in FIG.

[0119] It will be understood by those of ordinary skill in the art that the steps of the methods described in conjunction with the aspects disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. The software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. Additionally, in some aspects, the steps of the methods may reside as one or any combination or set of codes and / or instructions on a non-transitory computer-readable medium, which may be incorporated into a computer program product.

[0120] Although the present disclosure has been described with reference to specific embodiments of the present disclosure, it is apparent that many substitutions, modifications, and variations may be apparent to those skilled in the art. For example, the various components of the embodiments may be interchanged, added, or substituted in other embodiments. Moreover, all elements of each figure are not necessary for the operation of the disclosed embodiments. For example, a person of ordinary skill in the field of the disclosed embodiments will be able to make and use the teachings of the present disclosure by simply adopting the elements of the independent claims. Therefore, the embodiments of the present disclosure set forth herein are intended to be illustrative rather than restrictive. Various changes may be made without departing from the spirit and scope of the present disclosure.

[0121] In this file, the term "includes / including" or any other variation thereof is intended to cover non-exclusive inclusion, so that the process, method, article or equipment containing a list of elements not only contains those elements but also may contain other elements that are not explicitly listed or inherent to this process, method, article or equipment. Elements beginning with "a / an" or the like (without more constraints) do not exclude the presence of additional identical elements in the process, method, article or equipment containing the element. Moreover, the term "another" is defined as at least a second or more. As used herein, the term "having" and the like are defined as "comprising".

Claims

1. A method for transmitting radio link information, comprising: transmitting, at a second integrated access and backhaul node, the radio link information to the first integrated access and backhaul node, wherein the radio link information is associated with a backhaul link, The radio link information includes a status indication of the backhaul link, wherein the status indication is used to indicate a radio link failure recovery failure, and wherein the radio link information is transmitted in response to expiration of a reestablishment start timer or expiration of a reestablishment request timer. 2 . The method according to claim 1 , wherein the radio link information includes information indicating two nodes terminating the backhaul link.

3. The method of claim 1, further comprising transmitting second radio link information associated with the backhaul link, wherein the second radio link information comprises a second status indication indicating that a failure has occurred on the backhaul link and an attempt to recover from the failure is in progress.

4. The method of claim 3, wherein the second radio link information is transmitted in response to: expiration of a synchronization timer; declaration of failure of said radio link; initiation of the RRC connection re-establishment procedure; or Transmission of a Radio Resource Control Reestablishment Request message. The method of claim 1 , wherein the radio link information is transmitted via an adaptation layer message.

6. The method of claim 1 , further comprising transmitting third radio link information associated with the backhaul link, wherein the third radio link information comprises a third status indication indicating recovery from a radio link failure, wherein the third radio link information is transmitted in response to: Receipt of a RRC connection re-establishment message; or Transmission of the RRC Connection Reestablishment Complete message.

7. A method for receiving radio link information, comprising: receiving, at the first integrated access and backhaul node, the radio link information associated with the backhaul link from the second integrated access and backhaul node, The radio link information includes a state indication of the backhaul link, wherein the state indication is used to indicate one of a first state, a second state, or a third state, wherein: The first status indicates that a failure has occurred on the backhaul link and an attempt to recover from the failure is in progress; The second state indicates recovery from a radio link failure; and The third state indicates a radio link failure recovery failure; and Wherein the state indication indicates the third state in response to expiration of a re-establishment start timer at the second integrated access and backhaul node or expiration of a re-establishment request timer at the second integrated access and backhaul node.

8. The method of claim 7, wherein the status indication indicates the first status in response to: expiration of a synchronization timer at the second integrated access and backhaul node; a declaration of the radio link failure at the second integrated access and backhaul node; initiation of a radio resource control connection re-establishment procedure at the second integrated access and backhaul node; or Transmission of a radio resource control re-establishment request message at the second integrated access and backhaul node. 9 . The method according to claim 7 , wherein the radio link information includes information indicating two nodes terminating the backhaul link.

10. The method of claim 7, wherein in a case where the status indication is for indicating the first status, the radio link information further comprises a value of a timer, and the method further comprises starting the timer in response to receiving the radio link information. 11 . The method of claim 10 , wherein in a case where the status indication is used to indicate the second status, the method further comprises stopping the timer in response to receiving the radio link information.

12. The method according to claim 7, further comprising: receiving a radio resource control signaling message including a value of a timer; starting the timer in response to receiving the radio link information in the case where the status indication is for indicating the first status; and The timer is stopped in response to receiving the radio link information in the case where the state indication is for indicating the second state.

13. The method of claim 10 or 12, wherein in response to expiration of the timer, the method further comprises: A reestablishment procedure is performed with a communication node that does not include a current serving cell of the first integrated access and backhaul node.

14. The method according to claim 7, wherein in the case where the state indication is used to indicate the first state, the radio link information further includes a pause indication indicating whether to pause a timer in a radio link control layer of the first integrated access and backhaul node.

15. The method according to claim 7, wherein in the case where the status indication is used to indicate the first status, the method further comprises: pausing or stopping a timer in a radio link control layer of the first integrated access and backhaul node; and The timer in the radio link control layer is prevented from starting.

16. The method according to claim 7, wherein in the case where the status indication is used to indicate the first status, the method further comprises: At least one of the following is prohibited: performing a random access procedure; transmission scheduling requests or buffer status reports; or Use configuration authorization.

17. The method according to claim 7, wherein in the case where the state indication is used to indicate the first state or the third state, the method further comprises: An alternate route exchange is performed where an alternate route is configured at the first integrated access and backhaul node and the alternate route does not include two nodes terminating the backhaul link.

18. The method according to claim 7, wherein in the case where the status indication is used to indicate the first status, the method further comprises: The uplink duplication is activated in a case where uplink duplication is configured at the first integrated access and backhaul node and is in a deactivated state.

19. The method according to claim 7, wherein in the case where the state indication is used to indicate the second state, the method further comprises: resuming a suspended timer in a radio link control layer of said first integrated access and backhaul node, or The timer in the radio link control layer is allowed to start.

20. The method according to claim 7, wherein in the case where the state indication is used to indicate the second state, the method further comprises: deactivating uplink duplication in a case where uplink duplication is activated at the first integrated access and backhaul node; and Allow at least one of the following: performing a random access procedure; transmission scheduling request or buffer status report; or Use configuration authorization.

21. The method according to claim 7, wherein in the case where the status indication is used to indicate the third status, the method further comprises: A reestablishment procedure is performed with a communication node that does not include a current serving cell of the first integrated access and backhaul node.

22. The method of claim 7, wherein the radio link information is received via an adaptation layer message.

23. The method of claim 7, wherein the first status further indicates that an attempt to recover from the failure is in progress.

24. An apparatus for transmitting radio link information, comprising: at least one receiving circuit system; at least one transmission circuit system; and at least one processor coupled to the at least one receive circuitry and the at least one transmit circuitry and configured to: transmitting the radio link information to an integrated access and backhaul node, wherein the radio link information is associated with a backhaul link, The radio link information includes a status indication of the backhaul link, wherein the status indication is used to indicate a radio link failure recovery failure, and wherein the radio link information is transmitted in response to expiration of a reestablishment start timer or expiration of a reestablishment request timer.

25. An apparatus for receiving radio link information, comprising: at least one receiving circuit system; at least one transmission circuit system; and at least one processor coupled to the at least one receive circuitry and the at least one transmit circuitry and configured to: receiving radio link information associated with a backhaul link from an integrated access and backhaul node, The radio link information includes a state indication of the backhaul link, wherein the state indication is used to indicate one of a first state, a second state, or a third state, wherein: The first status indicates that a failure has occurred on the backhaul link and an attempt to recover from the failure is in progress; The second state indicates recovery from a radio link failure; and The third state indicates a radio link failure recovery failure; and Wherein the status indication indicates the third status in response to expiration of a re-establishment start timer at the integrated access and backhaul node or expiration of a re-establishment request timer at the integrated access and backhaul node.

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