Method and apparatus for scheduling request and buffer status report transmission

Abstract

The present disclosure relates to a method and an apparatus. According to some embodiments of the present disclosure, a method includes: receiving, at a communication device, a first buffer status report; and triggering, if a triggering condition is satisfied, a preemptive buffer status report based on the first buffer status report.

Description

Technical Field

[0001] The present disclosure generally relates to wireless communication technologies, and more particularly to scheduling request or buffer status report transmissions in a wireless communication system. Background Art

[0002] In a wireless communication system, a buffer status report procedure is used to provide information about the size of data in the uplink (UL) buffer of a user equipment (UE) to a base station (BS) serving the UE. When UL data arrives at the UE transmission buffer, a buffer status report (BSR) may be triggered. A scheduling request (SR) is used to request UL resources. If the UE does not have UL resources available for BSR transmission, then an SR may be triggered.

[0003] When an SR is triggered, it may be considered pending until it is cancelled. In some cases, including for example if new resources become available for the uplink shared channel (UL-SCH), a pending SR may be cancelled, which may be granted by the BS through dynamic scheduling. In some cases, including for example when a BSR is included in a MAC PDU for transmission, a triggered BSR may be cancelled.

[0004] There is a need to efficiently schedule SR and BSR transmissions. Summary of the Invention

[0005] Embodiments of the present disclosure provide a method. The method may include receiving a first buffer status report (BSR) at a communication device; and triggering a pre-emptive buffer status report (Pre-BSR) based on the first BSR if a trigger condition is met. In an embodiment of the present application, the Pre-BSR includes the buffer status of the first BSR and the buffer statuses of one or more second BSRs pending at the communication device.

[0006] In an embodiment of the present application, the step of triggering the Pre-BSR may include triggering the Pre-BSR if the priority level of the logical channel (LCH) associated with the first BSR is higher than a priority threshold. In another embodiment of the present application, the step of triggering the Pre-BSR may include triggering the Pre-BSR if the delay value of the LCH associated with the first BSR is lower than a delay threshold. In yet another embodiment of the present application, the method may include starting a timer in response to triggering the Pre-BSR. The method may include prohibiting another Pre-BSR until the timer expires. The method may include triggering another Pre-BSR while the timer is running if the priority of the LCH included in the received third BSR is higher than the highest priority among the priorities of the LCHs included in the first BSR. The method may include triggering another Pre-BSR while the timer is running if the delay value of the LCH included in the received third BSR is lower than the lowest delay value among the delay values of the LCHs included in the first BSR.

[0007] In another embodiment of the present application, the method may include transmitting the Pre-BSR and starting a retransmission timer in response to the transmission of the Pre-BSR. The method may include retransmitting the Pre-BSR in response to the expiration of the retransmission timer if uplink data is expected to be received at the communication device.

[0008] In yet another embodiment of the present application, the method may include triggering a pre-emptive scheduling request (Pre-SR) if there is no uplink resource available for transmitting the Pre-BSR.

[0009] In an embodiment of the present application, the method may include maintaining the triggered Pre-SR if an uplink resource is granted that is large enough to accommodate all the outstanding data to be transmitted at the communication device but not large enough to accommodate the Pre-BSR. The uplink resource may not be large enough to accommodate the buffer status until the last event that triggered the Pre-BSR. In another embodiment of the present application, the method may include cancelling the triggered Pre-SR if an uplink resource is granted that is large enough to accommodate the Pre-BSR. The uplink resource may be large enough to accommodate the buffer status until the last event that triggered the Pre-BSR.

[0010] In an embodiment of the present application, the Pre-SR may be associated with an egress LCH corresponding to the ingress LCH having the highest priority among at least one ingress LCHs associated with the first BSR. In another embodiment of the present application, the Pre-SR may be associated with an egress LCH corresponding to the ingress LCH having the highest priority among at least one ingress LCHs associated with the first BSR and one or more other BSRs received at the communication device. In yet another embodiment of the present application, the Pre-SR is associated with an egress LCH corresponding to the ingress LCH associated with the SR received at the communication device. In yet another embodiment of the present application, the Pre-SR is associated with the egress LCH having the highest priority among at least one egress LCHs, and wherein the at least one egress LCH is associated with at least one logical channel group (LCG) indicated in the Pre-BSR.

[0011] In an embodiment of the present application, the method may include transmitting the first SR at the transmission opportunity if the Pre-SR is to be transmitted at a transmission opportunity the same as that of the first SR pending at the communication device. The first SR may be associated with an egress LCH having data for transmission. In yet another embodiment of the present application, the method may include transmitting, if the Pre-SR is to be transmitted at a transmission opportunity the same as that of the first SR pending at the communication device, one of the Pre-SR and the first SR of the LCH, which is associated with the LCH having the highest priority among the LCHs associated with the Pre-SR and the first SR. The first SR may be associated with an egress LCH having data for transmission.

[0012] In an embodiment of the present application, the method may include transmitting the PUSCH at the transmission opportunity if the Pre-SR is to be transmitted at a transmission opportunity the same as that of a physical uplink shared channel (PUSCH) without an uplink shared channel (UL-SCH).

[0013] Yet another embodiment of the present disclosure provides an apparatus. According to some embodiments of the present 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 cause the apparatus to perform a method according to some embodiments of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] 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 with reference to specific embodiments thereof, which are illustrated in the accompanying drawings. These drawings depict only exemplary embodiments of the present disclosure and are thus not to be considered as limiting its scope.

[0015] Figure 1 Illustrate a schematic wireless communication system according to some embodiments of the present disclosure;

[0016] Figure 2 Illustrate a schematic wireless communication system according to some embodiments of the present disclosure;

[0017] Figure 3 Illustrate a flowchart of an exemplary procedure for handling UL transmissions according to some embodiments of the present disclosure;

[0018] Figure 4 Illustrate a flowchart of an exemplary procedure for handling UL transmissions according to some embodiments of the present disclosure; and

[0019] Figure 5 Illustrate an exemplary block diagram of a device according to some embodiments of the present disclosure. Detailed Description of the Embodiments

[0020] The detailed description of the 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 implemented. It should be understood that the same or equivalent functions can be achieved by different embodiments that are intended to be covered within the spirit and scope of the present disclosure.

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

[0022] Referring 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 illustrated in Figure 1 , it is contemplated that in some other embodiments of the present disclosure, the wireless communication system 100 may also include more or fewer nodes. Although for simplicity,

[0023] the BS 110 that communicates with the 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(not described in the figure), the HSS is communicatively coupled to the MME. The BS 110 can operate based on standard protocols such as, for example, Long Term Evolution (LTE), Advanced LTE (LTE-A), New Radio (NR), or other suitable protocols. For example, the BS 110 can include an eNB or a gNB and can define one or more cells (e.g., cell 111). The RN 120 can include a relay node or an integrated access and backhaul node (IAB node). The UE 130A can include, for example but not limited to, a computing device, a wearable device, a mobile device, an IoT device, etc. The UE 130B can include a device that is the same as or similar to the UE 130A. The UE 130B can also include a device that is different from the UE 130A. Those skilled in the art should understand that as technology develops and progresses, the terms described in this disclosure may change, but should not affect or limit the principles and spirit of this disclosure.

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

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

[0026] Although for simplicity Figure 1 only the donor BS 110 is shown connected to a single UE, it is expected that the donor BS 110 can provide or establish connections with multiple UEs. Similarly, although for simplicity Figure 1 only the RN 120 is shown connected to a single UE, it is expected that the RN 120 can also provide or establish connections with multiple UEs.

[0027] The deployment of (a number of) RNs helps to enhance and / or extend the coverage of the backhaul link to the BS. The evolved universal terrestrial radio access network (E-UTRAN) supports relay via a modified version of the evolved universal terrestrial radio access (E-UTRA) radio interface (i.e., the BL, also known as the Un interface) by wirelessly connecting the RN to the eNB that serves the RN (referred to as the donor eNB (DeNB)). The radio interface that provides a radio protocol connection between the RN and the UE is called the Uu interface. The relay function and use of the RN / DeNB entities in the network are transparent to the operation of the connected UEs.

[0028] 3GPP is envisioning an IAB architecture for 5G (NR) communication networks to support multi-hop relaying. In other words, an IAB node may skip one or more IAB nodes before reaching the IAB donor. A single-hop can be regarded as a special case of multi-hop. Multi-hop backhaul is relatively advantageous as it provides a relatively larger coverage extension compared to single-hop backhaul. In a relatively high-frequency radio communication system (e.g., a radio signal transmitted in a band above 6 GHz), a relatively narrow or small signal coverage may benefit from multi-hop backhaul technology. Multi-hop backhaul further enables backhauling around obstacles (e.g., buildings in a cluttered urban deployment).

[0029] Figure 2 Describe a wireless communication system 200 according to some embodiments of the present disclosure.

[0030] Reference 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, it is expected that the wireless communication system 200 may include more donor nodes in some other embodiments of the present disclosure. Similarly, although for simplicity Figure 2 only four IAB nodes are illustrated in, it is expected that the wireless communication system 200 may include more or fewer IAB nodes in some other embodiments of the present disclosure. Although for simplicity Figure 2 only two UEs are illustrated in, it is expected that the wireless communication system 200 may include more or fewer UEs in some other embodiments of the present disclosure.

[0031] IAB node 220A and IAB node 220B may be directly connected to IAB donor 210. IAB donor 210 is the parent node of IAB node 220A and IAB node 220B. IAB node 220C may reach IAB donor 210 by skipping IAB node 220B. IAB node 220B is the parent IAB node of IAB node 220C. In other words, IAB node 220C may be a child IAB node of IAB node 220B.

[0032] The IAB node 220D can reach the IAB donor 210 by skipping the IAB nodes 220C and 220B. The IAB nodes 220B and 220C can be upstream IAB nodes of the IAB node 220D, and the IAB node 220C can be the parent IAB node of the IAB node 220D. The IAB nodes 220C and 220D can be downstream IAB nodes of the IAB node 220B.

[0033] The UEs 230A and 230B can be directly connected to the IAB node 220C. In other words, the UEs 230A and 230B can be served by the IAB node 220C. The IAB node 220C, the IAB node 220D, the UEs 230A and 230B can be downstream nodes of the IAB node 220B. The IAB node 220D, the UEs 230A and 230B can be child nodes of the IAB node 220C.

[0034] Although the IAB nodes 220A and 220B are connected to the same donor node, i.e., Figure 2 the IAB donor 210 in

[0035] According to some other embodiments of the present disclosure, each of the IAB nodes 220A, 220B, 220C, and 220D can be directly connected to one or more UEs.

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

[0037] Figure 3 A flowchart illustrating an exemplary procedure 300 for handling UL transmissions according to some embodiments of the present disclosure.

[0038] In Figure 3 the communication device 320D can reach the BS 310 by skipping the communication devices 320C and 320B. The communication device 320C can reach the BS 310 by skipping the communication device 320B.

[0039] In some instances, the communication device 320B can be used as Figure 2 the IAB node 220B shown in Figure 2 the communication device 320C can be used as Figure 2the IAB node 220D, UE 230A, or UE 230B shown in Figure 2 the IAB donor 210 shown in

[0040] Reference Figure 3 , the communication device 320D may have UL data to be transmitted on at least one logical channel. In operation 311, the communication device 320D may transmit an SR to its parent node (e.g., the communication device 320C) to request, for example, uplink shared channel (UL-SCH) resources.

[0041] In some embodiments of the present disclosure, the SR may be associated with at least one logical channel having data to be transmitted. Each logical channel may be assigned to a logical channel group (LCG). The parameters for assigning logical channels are defined in 3GPP specification TS 38.321. The LCG may contain at least one logical channel, e.g., four logical channels.

[0042] In operation 313, the communication device 320D may receive a UL grant for UL transmission from the communication device 320C. In operation 315, the communication device 320D may transmit a buffer status report (BSR) to the communication device 320C. The communication device 320C may allocate uplink resources for subsequent data transmission from the communication device 320D.

[0043] In some embodiments of the present disclosure, the BSR may contain the buffer status of at least one LCG. The at least one LCG contains at least one logical channel. The logical channels contained in the at least one LCG may hereinafter be referred to as the logical channels associated with the BSR or the logical channels contained in the BSR.

[0044] In some embodiments of the present disclosure, the BSR may be transmitted in a MAC control element (CE) of a MAC protocol data unit (PDU). In the header of the MAC PDU, there may be a sub-header indicating that the MAC CE contains the BSR. For example, in the header of the MAC PDU, there may be a corresponding field indicating the type of the BSR (e.g., a logical channel ID (LCID) field). The format of the MAC PDU is defined in 3GPP specification TS 38.321.

[0045] In operation 317, the communication device 320C may transmit a UL grant for subsequent data transmission from the communication device 320D to the communication device 320D. In operation 319, the communication device 320D may transmit the UL data together with the uplink resources allocated by the communication device 320C to the communication device 320C.

[0046] After receiving a UL transmission from a child communication device (e.g., communication device 320D), communication device 320C may perform UL scheduling similar to that described above with respect to operations 311 - 319.

[0047] For example, in operation 321, communication device 320C may transmit an SR to its parent node (e.g., communication device 320B). In operation 323, communication device 320C may receive a UL grant for UL data transmission from communication device 320B.

[0048] In operation 325, communication device 320C may transmit a BSR to communication device 320B. Communication device 320B may allocate uplink resources for subsequent data transmissions from communication device 320C.

[0049] In operation 327, communication device 320B may transmit a UL grant for subsequent data transmissions from communication device 320C to communication device 320C. In operation 329, communication device 320C may transmit UL data to communication device 320B using the uplink resources allocated by communication device 320B.

[0050] After receiving a UL data transmission from a child communication device (e.g., communication device 320C), communication device 320B may perform UL scheduling similar to that described above with respect to operations 311 - 319 and operations 321 - 329.

[0051] For example, in operation 331, communication device 320B may transmit an SR to its parent node (e.g., BS 310). In operation 333, communication device 320B may receive a UL grant for UL data transmission from BS 310.

[0052] In operation 335, communication device 320B may transmit a BSR to BS 310. BS 310 may allocate uplink resources for subsequent data transmissions from communication device 320B.

[0053] In operation 337, BS 310 may transmit a UL grant for subsequent data transmissions from communication device 320B to communication device 320B. In operation 339, communication device 320B may transmit UL data together with the uplink resources allocated by BS 310 to BS 310.

[0054] In some embodiments of the present disclosure, when a communication device has available UL resources (e.g., Physical Uplink Shared Channel (PUSCH) resources) to send a BSR, the SR may be cancelled. In this case, operations 311, 313, 321, 323, 331, and 333 described above may be cancelled. Figure 3 Operations

[0055] When the communication device does not have available UL resources to send a BSR, an SR will be sent to the parent node of the communication device to request that the parent node allocate resources for the communication device, as described above with respect to Figure 3 Operations 311, 313, 321, 323, 331, and 333 in

[0056] In Figure 3 In the exemplary procedure 300 shown in

[0057] After the communication device receives UL data from its child node, the communication device may transmit a BSR or an SR to its parent node. That is, the received data is stored in the buffer of the communication device. If not specifically indicated, this BSR or SR may be referred to as a BSR, a regular BSR, an SR, or a regular SR hereinafter. Figure 4 Another solution for handling UL data transmission is to transmit a BSR or an SR to the parent node before the communication device receives UL data from its child node, which can reduce the latency caused by UL scheduling. For example, in some embodiments of the present disclosure, the communication device may transmit a BSR or an SR to its parent node after receiving an SR or a BSR from its child node. In some embodiments of the present disclosure, the parent node may transmit a BSR or an SR to its parent node after it transmits a UL grant to its child node. This BSR and SR transmitted before receiving UL data from the child node are referred to as a preemptive BSR (Pre-BSR) or a preemptive SR (Pre-SR) hereinafter. The UL scheduling procedure using Pre-BSR or Pre-SR will be described in detail below with respect to

[0058] Figure 4 A flowchart illustrating an exemplary procedure 400 for handling UL transmission according to some embodiments of the present disclosure.

[0059] In Figure 4 In

[0060] In some instances, the communication device 420B may be used as Figure 2 the IAB node 220B shown in Figure 2 the communication device 420C may be used as Figure 2 the IAB node 220C shown in Figure 2 the communication device 420D may be used as the IAB node 220D, the UE 240A, or the UE 240B shown in

[0061] Reference Figure 4 , in some embodiments of the present disclosure, the program 400 may include operation 411 (represented by a dashed arrow as an option). In the operation, the BS 410 may transmit information for configuring a triggering condition to at least one communication device served by the BS 410 (e.g., communication device 420C).

[0062] In operation 413, the communication device 420C may receive a BSR from a child node (e.g., communication device 420D). In operation 415, the communication device 420C may transmit a UL grant to the communication device 420D. In some embodiments of the present disclosure, the communication device 420C may also receive a BSR from a child node different from the communication device 420D (e.g., communication device 420E, Figure 4 not shown in the figure). The communication device 420C may transmit a UL grant to the communication device 420E.

[0063] In some embodiments of the present disclosure, before the communication device 420D transmits a BSR to the communication device 420C, if there is no UL resource available for transmitting the BSR, then the communication device 420D may transmit an SR to the communication device 420C( Figure 4 not shown in the figure). After receiving a UL grant for UL transmission( Figure 4 not shown in the figure) from the communication device 420C, the communication device 420D may then transmit a BSR to the communication device 420C.

[0064] In operation 417, the communication device 420C may determine whether a triggering condition for transmitting a Pre-BSR or a Pre-SR is satisfied. If the communication device 420C determines that the triggering condition for transmitting a Pre-BSR or a Pre-SR is not satisfied, then the communication device 420C may not be triggered for Pre-BSR or Pre-SR transmission, and the program 400 may go to operation 437 and wait for subsequent operations. If the communication device 420C determines that the triggering condition for transmitting a Pre-BSR or a Pre-SR is satisfied, then the program 400 may go to operation 419.

[0065] In some embodiments of the present disclosure, the communication device 420C may determine whether the triggering condition is satisfied by determining whether the priority level of the logical channel associated with the BSR from the communication device 420D is higher than a priority threshold. If the priority level of the logical channel associated with the BSR from the communication device 420D is higher than the priority threshold, then the communication device 420C may determine that the triggering condition is satisfied.

[0066] For example, the value range of the priority of a logical channel can be from "0" to "7", where "0" can represent the highest priority level and "7" can represent the lowest priority level. The priority threshold can be set to "4". If the value of the priority of the logical channel associated with the BSR is "3", then the triggering condition is met because the priority level of the logical channel is higher than the priority threshold.

[0067] In some embodiments of the present disclosure, the communication device 420C can determine whether the triggering condition is met by determining whether the delay value of the logical channel associated with the BSR from the communication device 420D is lower than the delay threshold. If the delay value of the logical channel associated with the BSR from the communication device 420D is lower than the delay threshold, then the communication device 420C can determine that the triggering condition is met.

[0068] For example, the delay threshold can be set to 10 ms (milliseconds). If the delay value of the logical channel associated with the BSR from the communication device 420D is 9 ms, then the triggering condition is met because the delay value of the logical channel is lower than the delay threshold.

[0069] In some embodiments of the present disclosure, the communication device 420C can determine whether the triggering condition is met by determining whether the timer (T1) for prohibiting Pre-BSR is running. The communication device can start this timer each time it triggers a Pre-BSR and can prohibit another Pre-BSR until the timer T1 expires. For example, before receiving the BSR from the communication device 420D, the communication device 420C can trigger a Pre-BSR based on the BSR from a child node of the communication device 420C (e.g., the communication device 420E, which is not shown in Figure 4 ), and can start the timer T1 in response to triggering the above-mentioned Pre-BSR based on the BSR from the communication device 420E.

[0070] In some embodiments of the present disclosure, if the communication device 420C determines that the timer T1 is running, then the communication device 420C can determine that the triggering condition is not met. That is, the communication device 420C can prohibit any Pre-BSR. Otherwise, if the communication device 420C determines that the timer T1 has expired, then the communication device 420C can determine that the triggering condition is met. The communication device 420C can trigger a Pre-BSR accordingly.

[0071] In some embodiments of the present disclosure, although the timer (T1) for prohibiting Pre-BSR is running, if one or more other criteria are met, then the communication device 420C can still determine that the triggering condition is met. For example, the one or more other criteria can be related to the priority threshold, the delay threshold, or both.

[0072] In some embodiments of the present disclosure, if the priority level of the logical channels included in the BSR from communication device 420D is higher than the highest priority among the priorities of the logical channels included in the above-mentioned BSR from communication device 420E, then communication device 420C may determine that the trigger condition is met when timer Tl is running.

[0073] In some embodiments of the present disclosure, if the delay value of the logical channels included in the BSR from communication device 420D is lower than the lowest delay value among the delay values of the logical channels included in the above-mentioned BSR from communication device 420E, then communication device 420C may determine that the trigger condition is met when timer Tl is running.

[0074] Other criteria for determining whether the trigger condition is met may also be employed. These criteria may be employed alone or in any combination thereof.

[0075] In some embodiments of the present disclosure, the trigger condition may be configured by BS 410 via RRC signaling or F1 signaling, etc., as described above with respect to operation 411. The F1 interface is a point-to-point interface between endpoints. In some embodiments, the F1 interface may support the exchange of signaling information (i.e., (a)n F1 signaling) between endpoints and may support data transmission to the corresponding endpoints. For example, the F1 interface between BS 410 and communication device 420C may support the exchange of signaling information and data transmission between BS 410 and communication device 420C. In some embodiments of the present disclosure, the RRC signaling or F1 signaling from BS 410 may include configuration information indicating one or more of the following parameters: a priority threshold, a delay threshold, or a timer value. The definitions of these parameters are described above with respect to operation 417 and are thus omitted here. Other parameters may also be indicated in the configuration information. In some other embodiments, the trigger condition may be pre-configured.

[0076] Employing a trigger condition for transmitting a Pre-BSR or Pre-SR may be helpful because it may allow for the transmission of a Pre-BSR or Pre-SR in a more efficient manner.

[0077] In some embodiments of the present disclosure, the trigger condition may not be applied to communication device 420C. In other words, the above-described operation 417 may be eliminated, and communication device 420C may trigger a Pre-BSR or Pre-SR under any circumstances.

[0078] In operation 419, communication device 420C may determine whether there is UL resource available for Pre-BSR transmission. If UL resource is available for Pre-BSR transmission, then program 400 may proceed to operation 426. Otherwise, if there is no UL resource available for transmitting Pre-BSR, then program 400 may proceed to operation 421 to trigger Pre-SR.

[0079] At the communication device, a logical channel (ingress logical channel) from a sub-communication device of the communication device may be mapped to a corresponding logical channel (egress logical channel) leading to a parent node of the communication device.

[0080] For example, communication device 420C may receive data from logical channels LCH#D-1 and LCH#D-2 from communication device 420D, and may receive data from logical channels LCH#E-1, LCH#E-2, and LCH#E-3 from different sub-nodes (eg, communication device 420E, which is not shown in Figure 4 ). Logical channels LCH#D-1 and LCH#D-2 may be associated with logical channel group LCG#D-1, logical channels LCH#E-1 and LCH#E-2 may be associated with logical channel group LCG#E-1, and logical channel LCH#E-3 may be associated with logical channel group LCG#E-2. Communication device 420C may transmit data to the parent node (eg, communication device 420B) via logical channels LCH#C-1, LCH#C-2, and LCH#C-3 that may be associated with logical channel groups LCG#C-1, LCG#C-2, and LCG#C-3, respectively. Logical channels LCH#C-1, LCH#C-2, and LCH#C-3 may also be referred to as backhaul (BH) logical channels. Ingress logical channels LCH#D-1 and LCH#E-1 may be mapped to egress logical channel LCH#C-1, ingress logical channels LCH#D-2 and LCH#E-2 may be mapped to egress logical channel LCH#C-2, and ingress logical channel LCH#E-3 may be mapped to egress logical channel LCH#C-3. The mapping of ingress logical channels and egress logical channels is as follows.

[0081]

[0082] Table 1

[0083] As mentioned above, a BSR may be associated with at least one logical channel group, each logical channel group containing at least one logical channel. Similar to a conventional SR, a Pre-SR may be associated with at least one logical channel. After receiving a BSR from a sub-node (eg, communication device 420D), communication device 420C may determine a Pre-SR associated with the egress logical channel used to request UL resource for Pre-BSR transmission.

[0084] In operation 421, communication device 420C may determine a Pre-SR and may trigger the Pre-SR. The Pre-SR may be determined based on a received BSR or SR, a Pre-BSR that triggers the Pre-SR, or other suitable criteria.

[0085] In some embodiments of the present disclosure, communication device 420C may trigger a Pre-SR associated with an exit logical signal corresponding to an ingress logical channel having the highest priority among at least one ingress logical channel associated with a BSR received from a child node.

[0086] For example, communication device 420C may receive a BSR from communication device 420D indicating the buffer status of logical channel group LCG#D-1, which includes logical channels LCH#D-1 and LCH#D-2. Assuming that the priority level of logical channel LCH#D-1 is higher than that of logical channel LCH#D-2, then communication device 420C may trigger a Pre-SR associated with exit logical channel LCH#C-1, which corresponds to ingress logical channel LCH#D-1 as shown in Table 1.

[0087] In some embodiments of the present disclosure, communication device 420C may trigger a Pre-SR associated with an exit logical channel corresponding to an ingress logical channel having the highest priority among at least one ingress logical channel associated with a BSR from a child node and one or more other BSRs received at the communication device.

[0088] For example, communication device 420C may receive a BSR from communication device 420E ( Figure 4 not shown) indicating the buffer status of logical channel group LCG#E-1, which includes logical channels LCH#E-1 and LCH#E-2. Communication device 420C may also receive a BSR from communication device 420D indicating the buffer status of logical channel group LCG#D-1, which includes logical channels LCH#D-1 and LCH#D-2. Communication device 420C may determine to trigger a Pre-SR in response to the BSR from communication device 420D. Assuming that the priority level of logical channel LCH#D-1 is the highest among the priority levels of logical channels LCH#D-2, LCH#E-1, and LCH#E-2, then communication device 420C may trigger a Pre-SR associated with exit logical channel LCH#C-1, which corresponds to ingress logical channel LCH#D-1 as shown in Table 1.

[0089] In some embodiments of the present disclosure, the communication device 420C may trigger a Pre-SR associated with an exit logical channel associated with an entrance logical channel corresponding to an SR received at the communication device.

[0090] For example, the communication device 420C may receive an SR from the communication device 420D to request a UL grant for BSR transmission ( Figure 4 not shown in ). The SR may be associated with at least one of the logical channels LCH#D-1 and LCH#D-2. After receiving the UL grant, the communication device 420D may then transmit a BSR to the communication device 420C. The communication device 420C may determine to trigger a Pre-SR in response to the BSR from the communication device 420D. Assuming the SR from the communication device 420D is associated with the logical channel LCH#D-1, the communication device 420C may trigger a Pre-SR associated with the exit logical channel LCH#C-1, which corresponds to the entrance logical channel LCH#D-1 as shown in Table 1.

[0091] In some embodiments of the present disclosure, an SR received from a child node may be associated with two or more entrance logical channels, and the two or more entrance logical channels may correspond to two or more different exit logical channels. The communication device 420C may determine to trigger a Pre-SR associated with one of these exit logical channels. In some instances, the communication device 420C may trigger a Pre-SR associated with the exit logical channel having the highest priority among these exit logical channels. In some instances, the communication device 420C may trigger a Pre-SR associated with the exit logical channel corresponding to the entrance logical channel having the highest priority among the two or more entrance logical channels. In some instances, the communication device 420C may randomly trigger a Pre-SR associated with one of the exit logical channels.

[0092] In some embodiments of the present disclosure, the communication device 420C may trigger a Pre-SR associated with the exit logical channel having the highest priority among at least one of the exit logical channels associated with at least one logical channel group indicated in the Pre-BSR.

[0093] For example, the communication device 420C may determine to trigger a Pre-SR to request UL resources for Pre-BSR transmission. Similar to a regular BSR, a Pre-BSR may be associated with at least one logical channel group, and each logical channel group includes at least one logical channel. For example, the Pre-BSR may indicate the buffer status of LCG#C-1, LCG#C-2, and LCG#C-3, where LCG#C-1, LCG#C-2, and LCG#C-3 include the egress logical channels LCH#C-1, LCH#C-2, and LCH#C-3, respectively. Assuming that the priority level of the egress logical channel LCH#C-1 is the highest among the priority levels of the egress logical channels LCH#C-1, LCH#C-2, and LCH#C-3, the communication device 420C may trigger a Pre-SR associated with the egress logical channel LCH#C-1.

[0094] In some embodiments of the present disclosure, a triggered Pre-SR may be cancelled. For example, after triggering a Pre-SR, the communication device 420C may receive a UL grant from its parent node. The UL grant may indicate UL resources for UL transmission (transmission opportunity) having a certain size and time. The communication device 420C may determine whether the UL resources are large enough to accommodate all the pending data and the Pre-BSR for transmission at the communication device 420C. If the UL resources are not large enough to accommodate the Pre-BSR, the triggered Pre-SR may be maintained. For example, if the UL resources are large enough to accommodate all the pending data for transmission but not large enough to further accommodate the Pre-BSR, or if the UL resources are not large enough to accommodate all the pending data for transmission, the triggered Pre-SR may be maintained. Otherwise, if the UL resources are large enough to accommodate the Pre-BSR, the triggered Pre-SR may be cancelled. If the UL resources are large enough to accommodate all the pending data for transmission but not large enough to accommodate the Pre-BSR, the pending SR may be cancelled.

[0095] In some embodiments of the present disclosure, the communication device 420C may determine whether the UL resources are large enough to accommodate the buffer status up to the last event that triggered the Pre-BSR. If the UL resources are not large enough to accommodate the buffer status up to the last event that triggered the Pre-BSR, the triggered Pre-SR may be maintained. Otherwise, if the UL resources are large enough to accommodate the buffer status up to the last event that triggered the Pre-BSR, the triggered Pre-SR may be cancelled.

[0096] For example, the communication device 420C may determine whether the UL resource is large enough to accommodate the buffer status of all triggered Pre-BSRs pending at the communication device. If the UL resource is not large enough to accommodate the buffer status of all triggered Pre-BSRs pending at the communication device, then the triggered Pre-SR may be maintained. Otherwise, if the UL resource is large enough to accommodate the buffer status of all triggered Pre-BSRs pending at the communication device, then the triggered Pre-SR may be maintained.

[0097] In operation 423, the communication device 420C may transmit the Pre-SR to the parent node of the communication device 420C (e.g., the communication device 420B) at a transmission opportunity. In operation 425, in response, the communication device 420B may transmit a UL grant.

[0098] In some embodiments of the present disclosure, the communication device 420C may determine that a regular SR is pending at the communication device. The regular SR may be associated with at least one exit logical channel having data to be transmitted. The communication device 420C may determine that the Pre-SR and the regular SR may be transmitted at the same transmission opportunity (e.g., TO0). In other words, the transmission of the Pre-SR may conflict with the transmission of the regular SR. In this case, the communication device 420C must select one of the Pre-SR and the regular SR to transmit at a given time (e.g., one at transmission opportunity TO0 and the other at a transmission opportunity after TO0).

[0099] In some embodiments of the present disclosure, the regular SR may be given a transmission priority. For example, the communication device 420C transmits the regular SR at transmission opportunity TO0 and transmits the Pre-SR at a transmission opportunity after TO0.

[0100] In some embodiments of the present disclosure, one of the Pre-SR and the regular SR associated with the logical channel having the highest priority among the logical channels associated with the Pre-SR and the regular SR may be given a transmission priority. For example, if the communication device 420C determines that the Pre-SR is associated with a logical channel having a priority higher than the highest priority among the logical channels associated with the regular SR, then the Pre-SR may be given a transmission priority. For example, the communication device 420C transmits the Pre-SR at transmission opportunity TO0 and transmits the regular SR at a transmission opportunity after TO0. Otherwise, the communication device 420C transmits the regular SR at transmission opportunity TO0 and transmits the Pre-SR at a transmission opportunity after TO0.

[0101] In some embodiments of the present disclosure, the communication device 420C may select one of the Pre-SR and the regular SR according to other suitable criteria.

[0102] In some embodiments of the present disclosure, the communication device 420C may determine to transmit a PUSCH without UL-SCH. For example, the communication device 420C may determine to report channel state information (CSI) without data.

[0103] In some embodiments of the present disclosure, the communication device 420C may determine to transmit a PUSCH without UL-SCH at a transmission opportunity (TO0) that is the same as the transmission opportunity of the Pre-SR. In other words, the transmission of the Pre-SR may conflict with the transmission of the PUSCH without UL-SCH. In some embodiments, the PUSCH without UL-SCH may be given a transmission priority. For example, the communication device 420C may transmit the PUSCH at the transmission opportunity TO0 and may transmit the Pre-SR at a transmission opportunity after the transmission opportunity TO0. In some embodiments, the Pre-SR may be given a transmission priority.

[0104] In some embodiments of the present disclosure, a regular SR may be transmitted at a transmission opportunity (TO0) that is the same as the transmission opportunity of the PUSCH without UL-SCH. In other words, the transmission of the regular SR may conflict with the transmission of the PUSCH without UL-SCH. In some embodiments, the regular SR may be given a transmission priority. For example, the communication device 420C may transmit the regular SR at the transmission opportunity TO0 and may transmit the PUSCH at a transmission opportunity after the transmission opportunity TO0. In some embodiments, the PUSCH without UL-SCH may be given a transmission priority.

[0105] In operation 426, the communication device 420C may trigger a Pre-BSR based on the BSR received from the communication device 420D. The Pre-BSR may include the buffer status of the BSR received from the communication device 420D. In some embodiments of the present disclosure, the Pre-BSR may further include the buffer status of one or more other BSRs pending at the communication device. For example, the communication device 420B may receive a BSR from a different sub-node (e.g., the communication device 420E, which is not shown in Figure 4 ). The Pre-BSR may include the buffer status of the BSR received from the communication device 420D and the buffer status of the BSR received from the communication device 420E.

[0106] In some embodiments of the present disclosure, the communication device 420C may start a timer (T1) for prohibiting another Pre-BSR in response to triggering the Pre-BSR in operation 426. The mechanism of the timer T1 is described above with respect to operation 417 and is thus omitted here.

[0107] Similar to the regular BSR, the Pre-BSR can also be transmitted in the MAC CE of the MAC PDU. In the header of the MAC PDU, there may be a sub-header indicating that the MAC CE contains the Pre-BSR. In some embodiments of the present disclosure, the triggered Pre-BSR or regular BSR can be cancelled.

[0108] In some embodiments of the present disclosure, the Pre-BSR and the regular BSR can be transmitted in a separate MAC CE. In some instances, if the UL resources are large enough to accommodate all the pending data available for transmission but not large enough to additionally accommodate the MAC CE for the regular BSR plus the sub-header for the MAC CE, then all the triggered regular BSRs can be cancelled. In some instances, if a MAC PDU is transmitted and this MAC PDU contains an early BSR MAC CE for the Pre-BSR that contains the buffer status up to (and including) the last event that triggered the Pre-BSR before the MAC PDU assembly, then all the Pre-BSRs triggered before the MAC PDU assembly can be cancelled.

[0109] In some embodiments of the present disclosure, the Pre-BSR and the regular BSR can be combined for transmission in the MAC CE for the BSR (combined BSR MAC CE). In other words, the combined BSR or the combined BSR MAC CE can contain the buffer status corresponding to the pending data available for transmission and the buffer status corresponding to the data to be received (pre-emptive buffer status). In some instances, if the BSR is not triggered by the pre-emptive buffer status, then all the triggered BSRs can be cancelled provided that the UL resources are large enough to accommodate all the pending data available for transmission but not large enough to additionally accommodate the MAC CE for the BSR plus the sub-header for the MAC CE. In some instances, if a MAC PDU is transmitted and this MAC PDU contains a combined BSR MAC CE that contains the buffer status up to (and including) the last event that triggered the BSR (Pre-BSR or regular BSR) before the MAC PDU assembly, then all the BSRs (including Pre-BSR and regular BSR) triggered before the MAC PDU assembly can be cancelled.

[0110] In operation 427, the communication device 420C can transmit the Pre-BSR to the communication device 420B at a transmission opportunity, and the communication device 420B can transmit a UL grant in response in operation 429.

[0111] In operation 431, in response to the transmission of the Pre-BSR, the communication device 420C may start a retransmission timer. In operation 433, the communication device 420C may determine whether to retransmit the Pre-BSR to the communication device 420B in response to the expiration of the retransmission timer. If the communication device 420C determines that the Pre-BSR does not need to be retransmitted, then the program 400 may proceed to operation 437 and wait for subsequent operations. Otherwise, in operation 435, the communication device 420C may retransmit the Pre-BSR to the communication device 420B.

[0112] In some embodiments of the present disclosure, the communication device 420C may determine whether to retransmit the Pre-BSR at the expiration of the retransmission timer by determining whether UL data is expected to be received at the communication device 420C. If it is determined that UL data is expected to be received at the communication device 420C, then the communication device 420C may retransmit the Pre-BSR to the communication device 420B.

[0113] For example, the communication device 420C may learn the amount of data initially expected from its child nodes (e.g., the communication device 420D) based on the BSRs received from its child nodes. At the expiration of the retransmission timer, the communication device 420C may receive all or part of the data initially expected from the child nodes and may transmit all or part of the received data to the corresponding parent nodes (e.g., the communication device 420B).

[0114] The communication device 420C may determine whether UL data is to be received at the communication device 420C by, for example, comparing the initially expected amount of data with the amount of data received. If it is determined that the initially expected amount of data is greater than the amount of data received, i.e., UL data is to be received at the communication device 420C, then in operation 435 the communication device 420C may retransmit the Pre-BSR to the corresponding parent nodes (e.g., the communication device 420B).

[0115] In some embodiments of the present disclosure, the transmitted Pre-BSR may indicate the amount of UL data received at the communication device 420C. For example, the transmitted Pre-BSR may indicate the difference between the initially expected amount of data and the amount of data received.

[0116] Although the exemplary program 400 shows operation 417 occurring after operation 415, i.e., in response to transmitting a UL grant to a child node, those skilled in the art will appreciate that, without departing from the spirit and scope of the present disclosure, operation 417 may occur at various stages of the UL transmission. For example, operation 417 may occur after operation 413, i.e., in response to receiving a BSR from a child node.

[0117] Although illustrative program 400 shows operations 411-437, those skilled in the art will appreciate that some of the operations 411-437 may be eliminated without departing from the spirit and scope of the present disclosure.

[0118] Figure 5 Example block diagram illustrating device 500 according to some embodiments of the present disclosure.

[0119] As Figure 5 shown, device 500 may include at least one non-transitory computer-readable medium ( Figure 5 not shown in Figure 5 ), receiving circuitry 502, transmitting circuitry 504, and a processor 506 coupled to the non-transitory computer-readable medium ( Figure 5 not shown in

[0120] ), receiving circuitry 502, and transmitting circuitry 504. Device 500 may be a BS or a communication device (e.g., an IAB node or a UE).

[0120] Although in this figure, elements such as processor 506, transmitting circuitry 504, and receiving circuitry 502 are described in the singular, plural forms are contemplated unless explicitly stated to be limited to the singular. In some embodiments of the present disclosure, receiving circuitry 502 and transmitting circuitry 504 are combined into a single device, such as a transceiver. In certain embodiments of the present disclosure, device 500 may further include an input device, a memory, and / or other components.

[0121] In some embodiments of the present disclosure, the non-transitory computer-readable medium may store computer-executable instructions thereon to cause the processor to implement a method regarding a communication device as described above. For example, the computer-executable instructions, when executed, cause processor 506 to interact with receiving circuitry 502 and transmitting circuitry 504 to perform steps regarding Figure 2 the IAB nodes and UEs depicted in Figure 3 and 4 the communication devices depicted in

[0122] In some embodiments of the present disclosure, the non-transitory computer-readable medium may store computer-executable instructions thereon to cause the processor to implement the method as described above regarding a BS. For example, the computer-executable instructions, when executed, cause processor 506 to interact with receiving circuitry 502 and transmitting circuitry 504 to perform steps regarding Figure 2 the IAB donor depicted in Figure 3 and 4 the BSs depicted in

[0123] One of ordinary skill in the art will appreciate that the steps of the methods described in connection with the aspects disclosed herein can be embodied directly in hardware, in software modules executed by a processor, or in a combination of both. The software modules can 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 can reside as code and / or instructions on a non-transitory computer-readable medium, which can be incorporated into a computer program product.

[0124] Although the present disclosure has been described in terms of its specific embodiments, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art. For example, various components of the embodiments may be interchanged, added, or replaced in other embodiments. Also, all elements of each figure are not necessary for the operation of the disclosed embodiments. For example, one of ordinary skill in the art in the field of the disclosed embodiments will be able to make and use the teachings of the present disclosure by simply employing the elements of the independent claims. Thus, the embodiments of the present disclosure as set forth herein are intended to be illustrative and not restrictive. Various changes can be made without departing from the spirit and scope of the present disclosure.

[0125] In this document, the term "includes", "including", or any other variant thereof is intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element preceded by "a", "an", etc. does not, without further limitation, preclude the presence of additional identical elements in the process, method, article, or apparatus that includes the element. Also, the term "another" is defined as at least a second or more. As used herein, the term "has", etc. is defined as "includes".

Claims

1. A method performed by a communication device, comprising: Receiving, at the communication device, a first buffer status report (BSR); Triggering a pre-emptive buffer status report (Pre-BSR) based on the first BSR if a triggering condition is met; Triggering a pre-emptive scheduling request (Pre-SR) if there is no uplink resource available for transmitting the Pre-BSR; And Canceling the triggered Pre-SR if an uplink resource is granted large enough to accommodate the Pre-BSR.

2. The method according to claim 1, wherein the Pre-BSR includes the buffer status of the first BSR and the buffer statuses of one or more second BSRs pending at the communication device.

3. The method according to claim 1 or 2, wherein: Triggering the Pre-BSR includes triggering the Pre-BSR if a priority level of a logical channel (LCH) associated with the first BSR is higher than a priority threshold.

4. The method according to claim 1 or 2, wherein: Triggering the Pre-BSR includes triggering the Pre-BSR if a delay value of a logical channel (LCH) associated with the first BSR is lower than a delay threshold.

5. The method according to claim 1 or 2, further comprising: Starting a timer in response to triggering the Pre-BSR.

6. The method according to claim 5, further comprising: Forbidding another Pre-BSR until the timer expires.

7. The method according to claim 5, further comprising: Triggering another Pre-BSR when the timer is running if a priority of a logical channel (LCH) included in a received third BSR is higher than the highest priority among the priorities of the LCHs included in the first BSR.

8. The method according to claim 5, further comprising: Triggering another Pre-BSR when the timer is running if a delay value of a logical channel (LCH) included in a received third BSR is lower than the lowest delay value among the delay values of the LCHs included in the first BSR.

9. The method according to claim 1 or 2, further comprising: Transmitting the Pre-BSR; And Starting a retransmission timer in response to the transmission of the Pre-BSR.

10. The method according to claim 9, further comprising: Retransmitting the Pre-BSR in response to expiration of the retransmission timer if uplink data is expected to be received at the communication device.

11. The method according to claim 1, further comprising: Maintaining the triggered Pre-SR if an uplink resource is granted large enough to accommodate all pending data for transmission at the communication device but not large enough to accommodate the Pre-BSR.

12. The method according to claim 11, wherein the uplink resource is not large enough to accommodate the buffer status until the last event that triggers the Pre-BSR.

13. The method according to claim 1, wherein the uplink resource is large enough to accommodate the buffer status until the last event that triggers a Pre-BSR.

14. The method according to claim 1, wherein the Pre-SR is associated with an exit LCH corresponding to an entry LCH having the highest priority among at least one entry logical channel LCHs associated with the first BSR.

15. The method according to claim 1, wherein the Pre-SR is associated with an exit LCH corresponding to an entry LCH having the highest priority among at least one entry logical channel LCHs associated with the first BSR and one or more other BSRs received at the communication device.

16. The method according to claim 1, wherein the Pre-SR is associated with an exit LCH corresponding to an entry logical channel LCH associated with a scheduling request SR received at the communication device.

17. The method according to claim 1, wherein the Pre-SR is associated with an exit LCH having the highest priority among at least one exit logical channel LCHs, and wherein the at least one exit LCH is associated with at least one logical channel group LCG indicated in the Pre-BSR.

18. The method according to claim 1, further comprising: If the Pre-SR is to be transmitted at a transmission opportunity that is the same as the transmission opportunity of a first SR pending at the communication device, then transmit the first SR at the transmission opportunity.

19. The method according to claim 18, wherein the first SR is associated with an exit logical channel LCH having data to be transmitted.

20. The method according to claim 1, further comprising: If the Pre-SR is to be transmitted at a transmission opportunity that is the same as the transmission opportunity of a first SR pending at the communication device, then transmit one of the Pre-SR and the first SR, which is associated with an LCH having the highest priority among the logical channel LCHs associated with the Pre-SR and the first SR.

21. The method according to claim 20, wherein the first SR is associated with an exit logical channel LCH having data to be transmitted.

22. The method according to claim 1, further comprising: If the Pre-SR is to be transmitted at a transmission opportunity that is the same as the transmission opportunity of a physical uplink shared channel PUSCH without an uplink shared channel UL-SCH, then transmit the PUSCH at the transmission opportunity.

23. A communication device, comprising: At least one non-transitory computer-readable medium storing computer-executable instructions; At least one receiving circuitry; At least one transmitting circuitry; And At least one processor coupled to the at least one non-transitory computer-readable medium, the at least one receiving circuitry, and the at least one transmitting circuitry, Wherein the at least one non-transitory computer-readable medium and the computer-executable instructions are configured to cause the communication device to perform the method according to any one of claims 1-22 using the at least one processor.

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