CN112469078A - Method and network device for transmitting buffer status report in multi-hop wireless network - Google Patents

Abstract

The present disclosure relates to a method used by a network device for transmitting buffer status reports in a multi-hop wireless network and a network device using the method. According to an exemplary embodiment, a method may include (without limitation): receiving priority information of a logical channel having a highest priority among a plurality of logical channels contained in a buffer status report message indicating radio resources required for upstream data from a child node; determining whether a condition is satisfied based on the priority information; and triggering a pre-emptive buffer status report message including priority information in response to the condition having been met.

Description

Method and network device for transmitting buffer status report in multi-hop wireless network

Technical Field

The present disclosure relates to a method used by a network device for transmitting buffer status reports in a multi-hop wireless network and a network device using the method.

Background

Conventionally, a Buffer Status Report (BSR) is transmitted from a mobile electronic device to a network to convey Media Access Control (MAC) Control Elements (CEs) that convey information about the amount of data that the mobile electronic device transmits to the outside. One purpose of the BSR is to subsequently get an Uplink (UL) grant from the network. The UL grant is typically transmitted to the mobile electronic device over a Physical Downlink Control Channel (PDCCH) and indicates radio resources allocated for data corresponding to the BSR that the UL resources are assumed to be available.

Fig. 1 depicts a multi-hop network including an Integrated Access and Backhaul (IAB) donor node and a plurality of IAB nodes (e.g., IAB node 1 and IAB node 2 of fig. 1) acting as hubs and relays. An IAB donor node will use the architecture of a split between a Centralized Unit (CU) and a Distribution Unit (DU), while an IAB node will use the architecture of a split between a Mobile Terminal (MT) and a DU. In the example of fig. 1, the IAB donor is wirelessly connected to IAB node 1, the IAB node 1 is wirelessly connected to IAB 2, the IAB 2 acts as a UE. The principle of operation of the example of fig. 1 is consistent with the current 5G standard (e.g., TR 38.874). Briefly, in order for a UE to transmit data to the network, the UE will transmit a Scheduling Request (SR) to IAB node 2, which then will transmit an UL grant to the UE for transmitting a BSR. The UE will then transmit a BSR to IAB node 2 to indicate the amount of data to be transmitted to the network. Upon receiving the BSR, IAB node 2 will transmit an UL grant to the UE for allocating radio resources for the data corresponding to the BSR to be transmitted. After receiving the UL grant, the UE transmits data in a Protocol Data Unit (PDU). The same signal flow will repeat between IAB node 2 and IAB node 1 and between IAB node 1 and the IAB donor node.

It has been noted that for the signalling flow as described for fig. 1, there will be scheduling delays in UL scheduling here due to the exchange of signalling, and the worst case may occur when no intermediate node has any UL resources allocated to it. Fig. 2A and 2B show two options for improving the signaling flow of a multihop network architecture for a 5G communication network. Fig. 2A depicts a method by which an IAB node may reduce UL scheduling latency through signaling of UL grants. With respect to this approach, transmission of a UL grant would mean that there is data available for transmission. Therefore, after transmitting the UL grant (step S201), IAB node 2 will transmit an SR to IAB node 1. Further, after transmitting the UL grant (step S202), IAB node 1 will transmit an SR to the IAB donor node. Fig. 2B illustrates a method by which an IAB node may reduce UL scheduling latency through signaling of an SR. With this approach, the reception of a BSR would mean that there is data available for transmission. Therefore, upon receiving the BSR (step S203), the IAB node 2 will transmit an SR to the IAB node 1. Further, upon receiving the BSR (step S204), the IAB node 1 will transmit an SR to the IAB donor node.

In order to distinguish between predicted data (i.e. predictive data) of a wireless electronic device to be transmitted in the future and available data of a wireless electronic device currently to be transmitted, a pre-implicit BSR has been proposed to work with a regular BSR. The pre-emptive BSR may be distinguished from the regular BSR based on a Logical Channel Identifier (LCID). The regular BSR has been formulated to limit the frequency with which it is triggered to reduce the signaling overhead of the MAC CE. Currently, a regular BSR may be triggered if UL data for a Logical Channel (LCH) belonging to a Logical Channel Group (LCG) becomes available to a MAC entity, and this UL data belongs to either a LCH having a higher priority than the priority of any LCH containing available UL data or a logical channel not belonging to a LCG containing any available UL data, which belongs to any LCG.

However, to limit the triggering of the pre-emptive BSR, the IAB node is currently unaware of whether the pre-emptive BSR for predictive data is triggered. One possible proposal is to have the preemptive BSR triggered if predictive data is to be transmitted over the LCH with the highest priority. However, this proposal is implemented in other details, may have the drawbacks of triggering a preemptive redundant BSR due to having received a regular BSR, triggering a meaningless preemptive BSR due to receiving a periodic BSR, and causing the parent IAB node to interpret the wrong SR configuration. Thus, unless there are other implementation details here to overcome the difficulties described above, there may be no implementation of a solution to trigger the preemptive BSR when transmitting predictive data over the LCH with the highest priority.

Disclosure of Invention

Accordingly, to limit the pre-emptive BSR to trigger less frequently and for the IAB node to know whether to transmit the pre-emptive BSR, the present disclosure relates to a method used by a network device for transmitting buffer status reports in a multi-hop wireless network and a network device using the method.

In one of the example embodiments, the present disclosure relates to a method for use by a network device for triggering buffer status reports in a multi-hop wireless network. Methods would include (without limitation): receiving first priority information of an LCH having a highest priority among a plurality of LCHs included in a first regular BSR message indicating radio resources required for upstream data from a child node; determining whether a condition is satisfied based on the first priority information; and triggering a pre-emptive BSR message containing the second priority information in response to the condition having been met.

In one of the exemplary embodiments, the present disclosure relates to a network device, comprising (without limitation): a transmitter, a receiver, and a processor coupled to the transmitter and the receiver. The processor is at least configured to: receiving, via a receiver, first priority information for an LCH having a highest priority among a plurality of LCHs contained in a BSR message indicating radio resources required for upstream data from a child node; determining whether a condition is satisfied based on the first priority information; and triggering, via the transmitter, a pre-emptive BSR message containing the second priority information in response to the condition having been satisfied.

In order to facilitate an understanding of the foregoing features and advantages of the disclosure, exemplary embodiments accompanied with figures are described in detail below. It is to be understood that both the foregoing general description and the following detailed description are exemplary and are intended to provide further explanation of the disclosure as claimed.

However, it is understood that this summary may not be free of all aspects and embodiments of the disclosure, and is therefore not intended to be limiting or restrictive in any way. In addition, the present disclosure will encompass improvements and modifications apparent to those skilled in the art.

Drawings

The accompanying drawings are included to provide a further understanding of the disclosure, and are incorporated into and constitute a part of this specification. The drawings illustrate embodiments of the disclosure and together with the description serve to explain the principles of the disclosure.

Fig. 1 shows a signaling flow for a multihop network architecture of a 5G communication network.

Fig. 2A shows an option for an improved signaling flow for a multihop network architecture of a 5G communication network.

Fig. 2B illustrates another option for improved signaling flow for a multihop network architecture of a 5G communication network.

Fig. 3 illustrates a method used by a network device for transmitting buffer status reports in a multi-hop wireless network according to an example embodiment of the present disclosure.

Fig. 4 illustrates a conceptual hardware block diagram of a network device in a multi-hop wireless network according to an example embodiment of the present disclosure.

Fig. 5 is an example illustrating triggering of a preemptive BSR for predictive data with 1-1 bearer mapping according to an exemplary embodiment of the present disclosure.

Fig. 6 illustrates a first example of a mechanism to trigger a preemptive BSR for predictive data according to a first exemplary embodiment of the present disclosure.

Fig. 7 illustrates a first alternative to the mechanism of fig. 6, in accordance with an embodiment of the present disclosure.

Fig. 8 illustrates a second alternative to the mechanism of fig. 6, in accordance with an embodiment of the present disclosure.

Fig. 9 illustrates a second example of a mechanism to trigger a preemptive BSR for predictive data according to a first exemplary embodiment of the present disclosure.

Fig. 10 shows a flow diagram of a trigger for implementing a pre-emptive BSR from the perspective of an intermediate IAB node, according to a second exemplary embodiment of the present disclosure.

Fig. 11 illustrates a format of a pre-BSR implemented in a MAC CE according to a first exemplary embodiment of the present disclosure.

Fig. 12 illustrates a format of a pre-BSR implemented in a MAC CE according to a second exemplary embodiment of the present disclosure.

Fig. 13 illustrates an example of a mechanism to trigger a preemptive BSR for predictive data according to a second exemplary embodiment of the present disclosure.

Description of the reference numerals

1. 2, IAB-1, IAB-2, IAB-3: integrating access and backhaul nodes;

400: a network device;

401: a hardware processor;

402: a wireless transmitter circuit;

403: a wireless receiver circuit;

404: a non-transitory storage medium;

501: establishing a load bearing;

502: a signaling flow;

1101. 1201: a first alternative;

1102. 1202: a second alternative;

DRB1, DRB2, DRB 3: a data radio bearer;

LCG0, LCG1, LCG 2: a group of logical channels;

LCH1, LCH2, LCH 3: a logical channel;

s201, S202, S203, S204, S301, S302, S303, S600, S601, S602, S603, S604, S605, S606, S608, S609, S610, S702, S703, S705, S708, S709, S710, S808, S810, S900, S901, S902, S903, S904, S905, S906, S908, S909, S910, S1001, S1002, S1003, S1300, S1301, S1302, S1303, S1304, S1305, S1306, S1307, S1308, S1309, S709: a step of;

UE1, UE2, UE 3: a user equipment.

Detailed Description

Reference will now be made in detail to the present exemplary embodiments of the disclosure, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts.

In general, the BSR procedure is used to provide the serving gNB with information about the amount of UL data in the MAC entity. The pre-emptive BSR may additionally be used by an IAB-MT to provide its parent IAB-DU with information about the amount of data expected to arrive at the IAB node's MT from its children and/or UEs attached to it.

To limit triggering of a pre-emptive BSR for predictive data, the present disclosure provides a mechanism to limit transmission of pre-emptive BSRs by a network device (e.g., an IAB node). The pre-emptive BSR for predictive data of an IAB node is triggered according to priority information provided from a child IAB node of the IAB node, and the priority information will indicate the highest priority. A child IAB node refers to an IAB node downstream from the IAB node. For example, IAB node 2 in fig. 1 is a child node of IAB node 1, and IAB node 1 is a parent node of IAB node 2. The priority information indicating the highest priority information refers to the priority of the logical channel having the highest priority in the LCH having the predictive and/or available data contained in the regular BSR provided from its child IAB node. The priority information may be indicated in the MAC CE of the pre-emptive BSR according to two different forms. The first alternate format includes a priority value in a 4-bit field (bit field). The second alternate format contains an LCH Identifier (ID) in a 6-bit field.

In addition, if the pre-emptive BSR and the regular BSR for the predictive data correspond to the same event, the regular BSR will be cancelled or not triggered when the predictive data becomes available. In other words, if a data arrival event has triggered a pre-BSR as expected, then the arrival of data does not trigger a regular BSR when the actual data corresponding to the predictive data has arrived. Thus, if a preemptive BSR is triggered, a regular BSR corresponding to the event is not triggered. When all or high priority expected data has been received after triggering the preemptive BSR, the subsequent BSR may be cancelled and thus no more BSRs will be triggered regardless of which LCH belongs to the LCG with the arriving predictive data.

The definition of the data amount of the predictive data can be defined according to two options. In option 1, the amount of data predicted to become available to the MAC entity may be the same as the amount of data indicated in the UL grant transmitted by the DU of the IAB node. In option 2, the amount of data predicted to become available to the MAC entity may be the same as the amount of data indicated in the BSR from the child IAB node or UE.

Benefits include limiting pre-emptive BSRs to trigger less frequently to reduce signaling overhead associated with transmitting predictive data and accurately determining SR configurations used by SRs triggered by corresponding BSRs for predictive data. The overall performance may depend on the configuration of the LCG and its corresponding LCH. In other words, efficiency may increase as LCGs have more LCHs.

Based on the inventive concepts described above, the present disclosure provides a method for use by a network device for transmitting buffer status reports in a multi-hop wireless network, as shown in fig. 3, and a corresponding network device, as shown in fig. 4. Referring to the method steps in fig. 3, in step S301, the network device will receive, from the child node, first priority information of an LCH having the highest priority among a plurality of LCHs contained in a first BSR message indicating radio resources required for upstream data from the child node, which may be another IAB node or similar wirelessly connected to the network device from downstream, through the network device. In step S302, the network device will determine whether the condition is satisfied based on the first priority information. In step S303, the network device will trigger a pre-BSR message containing second priority information in response to the condition having been met.

According to an exemplary embodiment, the network device will transmit an UL grant to the child node indicating UL resources. According to an example embodiment, the priority information may include an LCH ID. Alternatively, the priority information may include the priority of the LCH. According to an exemplary embodiment, the condition comprises priority information in a first regular BSR message transmitted from the child node indicating a higher priority than the priority of all other LCHs belonging to the LCG that contain predictive or available UL data. According to an exemplary embodiment, if the pre-emptive BSR and the second BSR correspond to the same event, the second BSR will be cancelled when predictive data becomes available. According to an example embodiment, the second BSR message does not indicate priority information when the priority information of the first BSR message is less than or equal to the priority of any other LCH containing predictive or available data.

According to an exemplary embodiment, the pre-emptive BSR is located in the MAC CE transmitted over PUSCH. The priority information described above may be located in the last octet (octet) of the preemptive BSR.

Referring to fig. 4, a conceptual hardware block diagram of a network apparatus 400 is shown. Network device 400 will include, without limitation, a hardware processor 401 that is electrically connected to a wireless transmitter circuit 402, a wireless receiver circuit 403, and a non-transitory storage medium. Network device 400 may be an IAB node, such as IAB node IAB-1, IAB node IAB-2, etc., as previously described. The network device 400 is at least configured to implement the method as described in fig. 3 and its corresponding exemplary embodiments. Wireless transmitter circuitry 402 may include one or more transmit circuits and receiver circuitry 403 may include one or more receive circuits configured to transmit and receive signals at radio frequencies or at millimeter wave frequencies, respectively. Transmitter circuitry 402 and receiver circuitry 403 may also perform operations such as low noise amplification, impedance matching, frequency mixing, frequency up or down conversion, filtering, amplification, and so forth. Transmitter circuit 402 and receiver circuit 403 may each include one or more digital-to-analog (D/a) or analog-to-digital (a/D) converters configured to convert from a digital signal format to an analog signal format during uplink signal processing or from an analog signal format to a digital signal format during downlink signal processing. Transmitter circuitry 402 and receiver circuitry 403 may each include an antenna array, which may include one or more antennas to transmit and receive an omni-directional antenna beam or a directional antenna beam. Non-transitory storage medium 404 will store programming code, codebook configurations, buffered data, and/or record configurations assigned by hardware processor 401. The hardware processor 401 may be implemented using programmable units such as microprocessors, microcontrollers, DSP chips, FPGAs, etc. The functions of the hardware processor 401 may also be implemented by separate electronic devices or ICs.

To further explain the methods and apparatus described above, the present disclosure provides exemplary embodiments and examples as shown in fig. 5-13 and described in their corresponding written descriptions. Fig. 5 shows an example of bearer establishment 501 and signaling flow 502 for a UE transmitting predictive data in a multi-hop wireless network. For bearer establishment, assume that there are at least three LCHs, with LCH1 being used for communication between the network and UE1, LCH2 being used for communication between the network and UE2, and LCH3 being used for communication between the network and UE 3. LCHs can pass through several hops (hops). For example, LCH1 relates to data traversing between the network and UE1 via at least an IAB donor, IAB node IAB-1, and IAB node IAB-2, and LCH2 and LCH3 relate to data traversing between the network and UE2 and between the network and UE3 via at least an IAB donor, IAB node IAB-1, IAB node IAB-2, and IAB node IAB-3. One or more LCHs can be grouped together into an LCG. In this example, LCG1 contains LCH1, LCH2, and LCH3 until between IAB node IAB-2 and IAB node IAB-3, where LCG1 contains LCH1 and LCH2 when UE1 is its own set LCG0 and communicates with IAB node IAB-2 over a Data Radio Bearer (DRB) 1. At IAB node IAB-3, UE2 and UE3 are each their own LCG group LCG0 and communicate with IAB node IAB-3 over data radio bearer DRB2 and data radio bearer DRB3, respectively.

To communicate the UE3 with the network, the signaling flow 502 is as follows. The UE3 will first transmit a regular BSR to the IAB node IAB-3 indicating the amount of predictive data to be transmitted. After receiving the regular BSR, IAB node IAB-3 will transmit an UL grant to UE3 indicating radio resources for transmitting predictive data to the network. In response to transmitting the UL grant, IAB node IAB-3 will transmit a pre-emptive BSR from UE3 to IAB node IAB-2 indicating the number of data expected. IAB node IAB-3 will then receive an UL grant from IAB node IAB-2 for transmitting predictive data to IAB node IAB-2. The IAB node IAB-3 will then receive the actual data from the UE 3. The IAB node IAB-3 will then forward the actual data to IAB node IAB-2 by using the UL grant received from IAB node IAB-2. The same flow will apply between IAB node IAB-2 and IAB node IAB-1 and between IAB node IAB-1 and the IAB donor.

For the first exemplary embodiment, fig. 6 shows a first example of a mechanism to trigger a pre-emptive BSR from the point of view of the IAB node IAB-1. Assume that LCH1 has a higher LCH priority than LCH2 and LCH2 has a higher LCH priority than LCH 3. In step S600, assume that LCG1 has LCH1, LCH2, and LCH3, and LCH2 carries 5 data units. In step S601, IAB node IAB-1 receives a regular BSR from IAB node IAB-2 indicating that 3 data elements in LCG1 are to be received. Notably, the BSR logs the data to be transmitted for the entire LCG. In step S602, IAB node IAB-1 will determine whether the data belongs to the LCH with the highest priority in LCG 1. In step S603, if the data belongs to LCH1, a preemptive BSR is triggered, but if the data belongs to LCH2 or LCH3, the preemptive BSR is not triggered. In step S604, IAB node IAB-1 will transmit an UL grant for the data to be received to IAB node IAB-2. In step S605, IAB node IAB-1 will transmit an SR for LCH1 to the IAB donor, and will subsequently receive an UL grant for a regular BSR from the IAB donor. In step S606, IAB node IAB-1 will receive the actual 3 data units from IAB node IAB-2 through LCH 3. In step S608, the IAB node IAB-1 will transmit a regular BSR to the IAB donor over PUSCH by using the UL grant received from the IAB donor, and the BSR will indicate 5 data units in LCH2 and 3 data units in LCH 3. In step S609, IAB node IAB-1 will receive UL grants from the IAB donor for 5 data units in LCH2 and 3 data units in LCH 3. In step S610, the IAB node IAB-1 will transmit data to the IAB donor over PUSCH.

Fig. 7 illustrates a first alternative to the mechanism of fig. 6, in accordance with an embodiment of the present disclosure. The steps of fig. 7 are similar to those of fig. 6, except as described below. In step S702, IAB node IAB-1 will receive regular BSRs from IAB node IAB-2 indicating three other future data units of LCH3 of LCG1 to be transmitted, except for 5 data units from LCH 2. The 5 data units from LCH2 in this example may be data to be transmitted periodically and that would require a periodic BSR to transmit in the absence of conditions to trigger a BSR. In step S703, IAB node IAB-1 will determine whether there is any highest priority LCH information for LCG 1. For IAB node IAB-1, the highest priority LCH information refers to one of LCH1, LCH2, and LCH3 that has the highest priority and has predictive and/or available data contained in the BSR provided from IAB node IAB-2. In step S703, IAB-1 has determined that there is no highest priority LCH information in LCG1 because the priority of LCH1 is highest in LCG1 but there is no data to be transmitted through LCH 1. Subsequently, a periodic (regular) BSR will be transmitted to inform that there will be 5 data units to be transmitted via LCH2 and 3 data units to be transmitted via LCH 3. In step S705, IAB node IAB-1 will transmit an SR for LCH2 to the IAB donor, and will then receive an UL grant for periodic BSR from the IAB donor. In step S708, the IAB node IAB-1 will transmit a periodic BSR to the IAB donor over the PUSCH indicating 5 data units to be transmitted via LCH2 and 3 data units to be transmitted via LCH3 by using the UL grant received from the IAB donor. Furthermore, in step S708, the BSR will indicate an LCH (i.e., LCH information: LCH2 in FIG. 7) for carrying the 5 data units indicated in the BSR. In this example, the LCH information would be the ID of LCH 2. In step S709, IAB node IAB-1 will receive UL grants from the IAB donor for 5 data units in LCH2 and 3 data units in LCH 3. In step S710, IAB node IAB-1 will transmit a BSR to the IAB donor indicating 3 data units to be transmitted via LCH3 of LCG1, and the BSR will indicate an LCH (i.e., LCH information: LCH3 in FIG. 7) for carrying the 3 data units indicated in the BSR.

Fig. 8 illustrates a second alternative to the mechanism of fig. 6, in accordance with an embodiment of the present disclosure. The mechanism of fig. 8 is the same as that of fig. 7 except for steps S808 and S810, and the BSR does not carry any LCH information. The BSR will only carry LCH information when the LCH priority of the preemptive BSR is greater than the LCH priority of the regular or periodic BSR. Because LCH1 is empty, there is no pre-emptive BSR to be triggered, and therefore, the BSRs in step S808 and step S810 do not contain any LCH information.

Fig. 9 shows a second example of a mechanism to trigger pre-BSR for predictive data. In this example, assume that LCH1 has a higher LCH priority than LCH2, and LCH2 has a higher LCH priority than LCH3, and LCH1, LCH2, and LCH3 are in the same LCG (i.e., LCG 1). In step S900, assume LCG2 carries 5 data units to be transmitted. In step S901, IAB node IAB-1 receives a regular BSR from IAB node IAB-2 indicating that 3 data elements in LCG1 are to be received. In step S902, IAB node IAB-1 will determine which LCH has the highest priority LCH information, and in this example, the LCH with the highest priority LCH information is LCH 1. In step S903, because LCH1 has the highest LCH priority in LCG1 and there is data to be transmitted via LCH1, the condition that triggers the pre-BSR has been met, and thus the pre-BSR will be transmitted. In step S904, IAB node IAB-1 will transmit an UL grant for the data to be received to IAB node IAB-2. In step S905, IAB node IAB-1 will transmit an SR for LCH1 to the IAB donor, and will subsequently receive an UL grant for the preemptive BSR from the IAB donor. In step S906, IAB node IAB-1 will receive the actual 3 data units from IAB node IAB-2. In step S908, the IAB node IAB-1 will transmit the pre-emptive BSR to the IAB donor over PUSCH by using the UL grant received from the IAB donor, and the pre-emptive BSR will indicate 5 data units in LCH2 and 3 data units in LCH 1. Further, in step S908, the pre-emptive BSR will indicate the LCH with the highest priority LCH information, which in this example is LCH 1. In step S909, IAB node IAB-1 will receive UL grants from the IAB donor for 5 data units in LCH2 and 3 data units in LCH 1. In step S910, the IAB node IAB-1 will transmit data to the IAB donor over PUSCH.

From the perspective of a network device, which may be any intermediate IAB node (e.g., IAB node IAB-1, IAB node IAB-2, IAB node IAB-3, etc.), a flow diagram for the case of triggering a pre-BSR is depicted in fig. 10. Referring to fig. 10, in step S1001, the intermediate IAB node will receive a BSR having priority information from the child IAB node. In step S1002, the intermediate IAB node will determine whether the condition has been satisfied based on the priority information. If the condition of step S1002 is not satisfied, the preemptive BSR is not triggered, but instead, the regular BSR or the periodic BSR is triggered. If the conditions of step S1002 have been met, the intermediate IAB node will trigger a pre-emptive BSR which may contain priority information for predictive data in step S1003. The priority information may be an LCH ID of an LCH to be used for transmitting predictive data or a priority value of an LCH to be used for transmitting predictive data.

The present disclosure provides a BSR format to accommodate the pre-emptive BSR, and the BSR format is illustrated in fig. 11 and 12. In general, the BSR may be located in the MAC CE, there may be a short BSR format as shown in fig. 11 and a long BSR format as shown in fig. 12. Referring to fig. 11, the short BSR format of the preemptive BSR will further include a single octet (i.e., an 8-bit field) containing priority information. The new octet may be one of two alternatives. For the first alternative 1101, an 8-bit field would include 4 spare field bits and 4 bits to indicate the priority value of the LCH. For the second alternative 1102, the 8-bit field would include 2 spare field bits and 6 bits to indicate the LCH ID. Thus, the priority information may be a priority value or LCH ID depending on which alternative is being used.

Referring to fig. 12, the long BSR format of the preemptive BSR will further include a single octet (i.e., an 8-bit field) containing priority information. Octets will be attached towards the end of the long BSR format. The new octet may also be one of two alternatives. For the first alternative 1201, the 8-bit field would include 4 spare field bits and 4 bits to indicate the priority value of the LCH. For second alternative 1202, the 8-bit field would include 2 spare field bits and 6 bits to indicate the LCH ID. Thus, the priority information may also be a priority value or LCH ID depending on which alternative is being used.

The present disclosure provides a second exemplary embodiment of a mechanism to trigger a pre-emptive BSR for predictive data. For the second exemplary embodiment, if the pre-emptive BSR and the regular BSR for the predictive data correspond to the same event, the regular BSR will be cancelled or not triggered when the predictive data becomes available. Thus, when a pre-emptive BSR is triggered, the regular BSR corresponding to the same event is cancelled, since it is no longer considered necessary. Thus, the triggering of the pre-emptive BSR will replace the regular or periodic BSR when the actual data has arrived.

Fig. 13 depicts an example of cancelling a BSR as a result of triggering a preemptive BSR for predictive data according to the second exemplary embodiment. This example assumes the same situation as the first exemplary embodiment: LCH1 has a higher LCH priority than LCH2 and LCH2 has a higher LCH priority than LCH3, and LCH1, LCH2, and LCH3 are in the same LCG (i.e., LCG 1). In step S1300, assume LCG2 carries 5 data units to be transmitted. In step S1301, IAB node IAB-1 receives a regular BSR from IAB node IAB-2 indicating that 3 data elements in LCG1 are to be received. In step S1302, IAB node IAB-1 will determine that LCH1 has the highest priority LCH information. In step S1303, the pre-emptive BSR will be transmitted because of the priority information of the LCH1 indicating matching conditions of fig. 10. In step S1304, IAB node IAB-1 will transmit an UL grant for the data to be received to IAB node IAB-2. In step S1305, IAB node IAB-1 will transmit an SR for LCH1 to the IAB donor, and will subsequently receive an UL grant for the preemptive BSR from the IAB donor. In step S1306, IAB node IAB-1 will receive the actual 3 data units from IAB node IAB-2. In step S1307, since the pre-BSR is triggered in step S1303, the regular BSR is no longer necessary and is thus cancelled. In step S1308, the IAB node IAB-1 will transmit a pre-emptive BSR to the IAB donor over PUSCH by using the UL grant received from the IAB donor, and the pre-emptive BSR will indicate 5 data units in LCH2 and 3 data units in LCH1 of LCG 1. Further, in step S1308, the pre-emptive BSR will indicate the LCH with the highest priority LCH information, which in this example is LCH 1. In step S1309, IAB node IAB-1 will receive an UL grant for 8 data units of LCG1 from the IAB donor. In step S1310, the IAB node IAB-1 will transmit data to the IAB donor over PUSCH.

In view of the foregoing description, the present disclosure is applicable for use in a 5G multihop wireless communication system and is capable of limiting the triggering of a pre-emptive BSR to reduce signaling overhead associated with transmitting predictive data.

No element, act, or instruction used in the detailed description of the disclosed embodiments of the present application should be construed as critical or essential to the disclosure unless explicitly described as such. Also, as used herein, each of the indefinite articles "a" or "an" can comprise more than one item. If only one item is intended, the term "single" or similar language will be used. Further, as used herein, the term "any of" preceding a list of a plurality of items and/or a plurality of categories of items is intended to encompass any combination of the items and/or categories of items "any of", "any combination of", "any plurality of" and/or "a plurality of the other items and/or categories of items, either individually or in combination with other items and/or categories of items. Additionally, as used herein, the term "set" is intended to encompass any number of items, including zero. Additionally, as used herein, the term "number" is intended to include any number, including zero.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims (19)

1. A method for use by a network device for triggering buffer status reports in a multi-hop wireless network, the method comprising:

receiving first priority information of a logical channel having a highest priority among a plurality of Logical Channels (LCHs) contained in a first Buffer Status Report (BSR) message indicating radio resources required for upstream data from a child node;

determining whether a condition is satisfied based on the first priority information; and

triggering a pre-emptive buffer status report message comprising second priority information in response to the condition having been met.

2. The method for use by a network device for triggering buffer status reports in a multi-hop wireless network of claim 1, further comprising:

transmitting an uplink grant to the child node indicating uplink resources.

3. The method for use by a network device for triggering buffer status reports in a multi-hop wireless network of claim 1, wherein said priority information comprises:

an Identifier (ID) of a logical channel.

4. The method for use by a network device for triggering buffer status reports in a multi-hop wireless network of claim 1, wherein said priority information comprises:

priority information of logical channels.

5. The method for use by a network device for triggering buffer status reports in a multi-hop wireless network of claim 1, wherein the conditions comprise:

whether the first priority information in the first buffer status report message indicates a higher priority than the priority of any other logical channel containing predictive or available data.

6. The method used by a network apparatus for triggering buffer status reports in a multi-hop wireless network of claim 5, wherein the preemptive buffer status report indicates the priority information of the first buffer status report message when the priority information is greater than a priority of any other logical channel containing predictive or available data.

7. The method used by a network apparatus for triggering buffer status reports in a multi-hop wireless network of claim 5, wherein the second buffer status report message does not indicate the priority information of the first buffer status report message when the priority information is less than or equal to a priority of any other logical channel containing predictive or available data.

8. The method for use by a network device for triggering buffer status reports in a multi-hop wireless network, according to claim 1, wherein the pre-emptive buffer status report is located in a Medium Access Control (MAC) Control Element (CE) transmitted over a Physical Uplink Shared Channel (PUSCH).

9. The method for use by a network device for triggering buffer status reports in a multi-hop wireless network of claim 1, wherein the priority information is located in the last octet of the preemptive buffer status report.

10. A method for use by a network device for cancelling a triggered buffer status report in a multi-hop wireless network, the method comprising:

receiving a first Buffer Status Report (BSR) message indicating radio resources required for upstream data from a child node;

triggering a pre-emptive buffer status report message in response to the first buffer status report;

receiving the upstream data from the child node;

triggering a second buffer status report message in response to the upstream data; and

canceling the second buffer status report in response to the pre-emptive buffer status report message and the second buffer status report message corresponding to the same upstream data.

11. A network device, comprising:

a transmitter;

a receiver; and

a processor coupled to the transmitter and the receiver and configured at least to:

receiving, via the receiver, first priority information of a logical channel having a highest priority among a plurality of Logical Channels (LCHs) included in a first Buffer Status Report (BSR) message indicating radio resources required for upstream data from a child node;

determining whether a condition is satisfied based on the first priority information; and

triggering a preemption buffer status report message including the second priority information in response to the condition having been met.

12. The network device of claim 11, wherein the processor is further configured to:

transmitting, by the transmitter, an uplink grant indicating the uplink resource to the child node.

13. The network device of claim 12, wherein the priority information comprises:

an Identifier (ID) of a logical channel.

14. The network device of claim 12, wherein the priority information comprises:

priority information of logical channels.

15. The network device of claim 11, wherein the condition comprises:

whether the first priority information in the first buffer status report message indicates a higher priority than the priority of any other logical channel containing predictive or available data.

16. The network apparatus of claim 15, wherein the preemptive buffer status report indicates the priority information of the first buffer status report message when the priority information is greater than a priority of any other logical channel containing predictive or available data.

17. The network apparatus of claim 15, wherein the second buffer status report message does not indicate the priority information of the first buffer status report message when the priority information is less than or equal to a priority of any other logical channel containing predictive or available data.

18. The network device of claim 11, wherein the pre-emptive BSR is located in a Medium Access Control (MAC) Control Element (CE) transmitted over a Physical Uplink Shared Channel (PUSCH).

19. The network device of claim 11, wherein the priority information is located in a last octet of the preemptive buffer status report.

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