Wireless battery management system and method of operating the same

Abstract

This disclosure relates to a wireless battery management system and its operation method. The wireless battery management system includes multiple cell monitoring units (CMUs) and a battery management unit (BMU). The multiple CMUs are configured to monitor multiple battery cells, and the BMUs are configured to perform wireless communication with and manage the multiple CMUs. The BMU requests the transmission of cell monitoring information from the multiple CMUs, and, based on any CMU transmission failure, prioritizes requesting retransmission of the cell monitoring information from the CMU that failed to transmit.

Description

[0001] Cross-references to related applications

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2024-0188517, filed with the Korean Intellectual Property Office on December 17, 2024, the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] This disclosure relates to a wireless battery management system and its operating method, and more specifically, to a wireless battery management system and its operating method for controlling high-voltage batteries used in electric vehicles and the like. Background Technology

[0004] The batteries used in environmentally friendly vehicles such as electric vehicles (EVs), hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (PHEVs) are high-voltage batteries that generate high voltage by connecting multiple battery cells of the same specifications in series or parallel.

[0005] A battery management system (BMS) is a device that controls and manages the charging and discharging of a high-voltage battery consisting of multiple battery cells. A BMS includes multiple cell monitoring units (CMUs) that monitor the battery cells and a battery management unit (BMU) that manages the multiple CMUs.

[0006] Based on the communication method between multiple CMUs and BMUs, battery management systems can be classified into wired battery management systems and wireless battery management systems. Wired battery management systems connect multiple CMUs and BMUs via wired cables, providing relatively stable communication; however, the use of multiple cables and connectors increases the vehicle's weight by tens of kilograms. On the other hand, wireless battery management systems interconnect multiple CMUs and BMUs wirelessly, significantly reducing the weight and size of the battery pack; however, communication performance may be impaired by external noise and the installation location / orientation of the CMUs.

[0007] To address these drawbacks, the wireless battery management system requests retransmission of cell monitoring information from CMUs that failed to transmit during the initial transmission cycle (first transmission cycle). However, in the wireless battery management system according to the prior art, regardless of whether the transmission was successful during the initial transmission cycle, all CMUs retransmit the cell monitoring information during the subsequent transmission cycle (second transmission cycle), resulting in a low communication success rate because CMUs that failed to transmit during the first transmission cycle may repeatedly fail to transmit in subsequent transmission cycles.

[0008] The statements in this Background section are provided only as background information in relation to this disclosure and may not constitute prior art. Summary of the Invention

[0009] This disclosure provides a wireless battery management system and its operating method, wherein in wireless communication between multiple CMUs and BMUs, when any CMU fails to transmit, retransmission is preferentially performed on the CMU that failed to transmit.

[0010] This disclosure may also provide a wireless battery management system and its operating method, wherein during wireless communication between multiple CMUs and BMUs, the BMU broadcasts an advertising packet including the identification information of the CMU that failed to transmit, and the CMU that failed to transmit prioritizes retransmitting cell monitoring information to the BMU.

[0011] This disclosure may also provide a wireless battery management system and its operating method, which sets transmission priorities for all CMUs and allows each of the multiple CMUs that have failed to transmit to the BMU based on the transmission priority when there are multiple CMUs that have failed to transmit.

[0012] This disclosure is not limited to the foregoing, and other aspects and advantages not mentioned above should be understood from the following description and will become more apparent from the implementation. Furthermore, aspects of this disclosure can be achieved by the means indicated in the claims and combinations thereof.

[0013] According to one aspect of this disclosure, a wireless battery management system includes: a plurality of cell monitoring units (CMUs) configured to monitor a plurality of battery cells; and a battery management unit (BMU) configured to perform wireless communication with the plurality of CMUs and manage the plurality of CMUs. The BMU requests the transmission of cell monitoring information from the plurality of CMUs, and, based on the failure of transmission from at least one CMU, preferentially requests retransmission of the cell monitoring information from the at least one CMU that experienced the transmission failure (e.g., the at least one CMU that experienced the transmission failure).

[0014] The BMU can broadcast advertising packets requesting the transmission of cell monitoring information to multiple CMUs. Each of the multiple CMUs can transmit cell monitoring information to the BMU during a first transmission cycle. Based on the failure of at least one CMU to transmit, the BMU can broadcast advertising packets including the identification information of the at least one CMU that failed to transmit, and the at least one CMU that failed to transmit can retransmit the cell monitoring information to the BMU during a second transmission cycle.

[0015] When two or more CMUs experience transmission failures, or based on the existence of two or more CMUs experiencing transmission failures, the BMU may broadcast an advertising packet containing identification information of the two or more CMUs that have experienced transmission failures, and each of the two or more CMUs experiencing transmission failures may retransmit cell monitoring information to the BMU during the corresponding time slot of the second transmission cycle. The corresponding time slot of the second transmission cycle may be set based on transmission priority, or may be assigned to each of the two or more CMUs experiencing transmission failures based on transmission priority.

[0016] According to another aspect of this disclosure, the operation method of the wireless battery management system includes: a battery management unit (BMU) requesting the transmission of cell monitoring information from a plurality of cell monitoring units (CMUs); each of the plurality of CMUs transmitting the cell monitoring information to the BMU during a first transmission cycle; the BMU prioritizing the request to retransmit the cell monitoring information from at least one CMU that failed to transmit the information, based on the failure of at least one CMU; and the at least one CMU that failed to transmit the information retransmit the cell monitoring information to the BMU during a second transmission cycle.

[0017] Requesting the transmission of cell monitoring information may include an advertising packet broadcast by the BMU to multiple CMUs requesting the transmission of cell monitoring information. Prioritizing the retransmission of cell monitoring information may include an advertising packet broadcast by the BMU to multiple CMUs, including identification information of at least one CMU whose transmission failed.

[0018] When two or more CMUs experience transmission failures, or based on the existence of two or more CMUs experiencing transmission failures, prioritizing the request to retransmit cell monitoring information may include: the BMU broadcasting an advertising packet containing the identification information of the two or more CMUs that failed to transmit the information to multiple CMUs. Retransmitting cell monitoring information to the BMU may include: each of the two or more CMUs that failed to transmit the information to the BMU during the corresponding time slot of the second transmission cycle. The corresponding time slot of the second transmission cycle can be set based on transmission priority.

[0019] According to one or more embodiments of this disclosure, in wireless communication between multiple CMUs and BMUs, when any CMU transmission fails, retransmission is preferentially performed on the CMU that failed to transmit, thereby mitigating the degradation of communication performance caused by external noise, CMU installation location / orientation, etc. that may occur in the wireless communication environment.

[0020] In addition, according to one or more embodiments of this disclosure, a transmission priority is set for all CMUs, and when there are multiple CMUs that have failed to transmit, each of the multiple CMUs that have failed to transmit retransmits the cell monitoring information based on the transmission priority, thereby significantly improving the communication success rate and correspondingly enhancing the communication performance. Attached Figure Description

[0021] The foregoing and other aspects, features, advantages, and embodiments described below should be better understood when read in conjunction with the accompanying drawings. However, this disclosure is not intended to be limited to the details shown in the drawings, and various modifications and structural changes may be made without departing from the spirit of this disclosure and within the scope and range of the equivalents of the claims. In the various drawings, the same reference numerals and symbols indicate the same elements.

[0022] Figure 1 This is a block diagram of a wireless battery management system according to one embodiment of the present disclosure.

[0023] Figure 2 This is a flowchart illustrating an operation method for a wireless battery management system according to one embodiment of the present disclosure.

[0024] Figure 3 A retransmission method for a wireless battery management system according to the prior art is shown.

[0025] Figure 4 A retransmission method for a wireless battery management system according to one embodiment of the present disclosure is shown. Detailed Implementation

[0026] The embodiments disclosed herein are described in more detail with reference to the accompanying drawings, and throughout the drawings, the same reference numerals are used to indicate the same or similar components, and redundant descriptions are omitted. As used herein, the terms "module" and "unit" used to refer to components are used interchangeably for ease of explanation, and therefore the terms themselves should not be considered to have different meanings or functions. Regarding the description of this disclosure, detailed descriptions of relevant prior art may be omitted when determined to unnecessarily obscure the gist of this disclosure. Furthermore, it should be understood that the drawings are intended only to aid in understanding the embodiments disclosed herein and do not limit the technical principles and scope of this disclosure. Rather, it should be understood that the drawings include all modifications, equivalents, or substitutions described by the technical principles and falling within the technical scope of this disclosure.

[0027] Although the terms first, second, third, etc., may be used herein to describe various elements, components, regions, layers, and / or parts, these elements, components, regions, layers, and / or parts should not be limited by these terms. These terms are used only to distinguish one element from another.

[0028] When a component or layer is referred to as being "attached to," "connected to," "coupled to," or "on" another component or layer, it may be directly attached to, directly connected to, or directly coupled to the other component or layer, or directly on the other component or layer, or there may be intermediate components or layers. Conversely, when a component or layer is referred to as being "directly attached to," "directly connected to," "directly coupled to," or "directly on" another component or layer, there may be no intermediate components or layers.

[0029] When a component, unit, controller, device, element, or apparatus of this disclosure is described as having a purpose or performing an operation or function, the component, unit, controller, device, element, or apparatus shall be regarded herein as "configured" to satisfy that purpose or perform that operation or function. Each component, unit, controller, device, element, or apparatus may be individually embodied as a processor and memory (such as a non-transitory computer-readable medium) or may be included together with a processor and memory as part of an apparatus.

[0030] As used in this specification, the terms "unit" or "module" refer to a single unit that performs at least one function or operation and can be implemented by hardware, software, or a combination of hardware and software. The operation or function of the methods described in conjunction with the forms disclosed herein can be directly embodied in hardware or software modules executed by a processor, or in a combination thereof.

[0031] In the following text, reference will be made to Figures 1 to 4 A wireless battery management system and its operation method according to embodiments of the present disclosure are described in detail.

[0032] Figure 1 This is a block diagram illustrating a wireless battery management system according to one embodiment of the present disclosure.

[0033] refer to Figure 1 According to one embodiment of the present disclosure, a wireless battery management system (100) includes multiple battery modules (110-1, 110-2, ..., 110-n), multiple cell monitoring units (CMUs) (120-1, 120-2, ..., 120-n), and a battery management unit (BMU) (130).

[0034] A battery module (110-1, 110-2, ..., 110-n) is a battery assembly consisting of one or more battery cells (e.g., 32 battery cells) connected in series and / or in parallel.

[0035] The CMU (120-1, 120-2, ..., 120-n) is a device for monitoring the battery cells of the battery modules (110-1, 110-2, ..., 110-n).

[0036] For example, the CMU (120-1, 120-2, ..., 120-n) senses the voltage, temperature, etc. of the battery cells of the battery module (110-1, 110-2, ..., 110-n) and generates cell monitoring information, and transmits the cell monitoring information to the BMU (130) according to the request of the BMU (130).

[0037] BMU (130) is a device that manages CMUs (120-1, 120-2, ..., 120-n) by communicating wirelessly with multiple CMUs (120-1, 120-2, ..., 120-n).

[0038] For example, the BMU (130) broadcasts an advertisement packet requesting the transmission of cell monitoring information to multiple CMUs (120-1, 120-2, ..., 120-n), and controls multiple CMUs (120-1, 120-2, ..., 120-n) based on the cell monitoring information received from multiple CMUs (120-1, 120-2, ..., 120-n), thereby performing charging / discharging control and cell balancing on the battery cells.

[0039] Additionally, if cell monitoring information transmission fails for any CMU (120-1, 120-2, ..., 120-n), the BMU (130) broadcasts an advertising packet containing the identification information of the failed CMU, enabling priority retransmission of cell monitoring information from the failed CMU. Using the node information of the CMU as the identification information of the CMU is advantageous.

[0040] Figure 2 This is a flowchart illustrating an operation method for a wireless battery management system according to one embodiment of the present disclosure.

[0041] First, in step S210, the BMU (130) requests the transmission of cell monitoring information from multiple CMUs (120-1, 120-2, ..., 120-n).

[0042] For example, BMU (130) broadcasts an ad packet requesting the transmission of cell monitoring information to multiple CMUs (120-1, 120-2, ..., 120-n).

[0043] Among the ADV_IND, ADV_DIRECT_IND, ADV_NONCONN_IND, and ADV_SCAN_IND packet types, the ADV_IND packet type is advantageous because it does not specify a device and can be connected to all nearby devices. The payload of the ADV packet includes information requesting the transmission of cell monitoring information from all CMUs (120-1, 120-2, ..., 120-n).

[0044] According to one embodiment of this disclosure, the information requesting the transmission of cell monitoring information from all CMUs (120-1, 120-2, ..., 120-n) can be implemented in the form of a specific command (e.g., all CMUs), or it can be implemented in the form of a flag identifying the CMUs (120-1, 120-2, ..., 120-n) to transmit cell monitoring information.

[0045] When the identification information of the CMUs (120-1, 120-2, ..., 120-n) to transmit cell monitoring information is implemented in the form of a flag, the BMU (130) can indicate the transmission request to the corresponding CMU by using bits corresponding to the number of CMUs (120-1, 120-2, ..., 120-n). For example, if there are 16 CMUs (CMU #1, CMU #2, ..., CMU #16), the BMU (130) can request all 16 CMUs to transmit cell monitoring information by indicating "1111 1111 1111 1111".

[0046] Then, in step S220, each of the multiple CMUs (120-1, 120-2, ..., 120-n) transmits cell monitoring information to the BMU (130) during the first transmission cycle.

[0047] For example, multiple CMUs (120-1, 120-2, ..., 120-n) receive advertising packets broadcast by BMU (130) and analyze the information included in the payload of the advertising packets to determine whether there is a request for transmission of cell monitoring information. As in step S210, when there is a request for transmission of cell monitoring information for all CMUs (120-1, 120-2, ..., 120-n), each CMU in the CMUs (120-1, 120-2, ..., 120-n) transmits its cell monitoring information to BMU (130) during a predetermined time slot period of that CMU in the first transmission cycle (i.e., the time slot period allocated to that CMU in the first transmission cycle). For reference, the transmission cycle consists of n time slots corresponding to the number of CMUs.

[0048] During the sequential transmission of cell monitoring information from all CMUs (120-1, 120-2, ..., 120-n) to BMU (130), transmission failures may occur due to external noise environment, CMU installation location / orientation, etc.

[0049] In this situation, as mentioned above, it is necessary to retransmit the CMU that failed to transmit.

[0050] Regarding this point, Figure 3 A retransmission method for a wireless battery management system according to the prior art is shown, and Figure 4 A retransmission method for a wireless battery management system according to one embodiment of the present disclosure is shown.

[0051] refer to Figure 3 In a wireless battery management system according to the prior art, during the first transmission cycle, any CMU ( Figure 3 When cell monitoring information transmission fails for CMU #2, another request for retransmission of cell monitoring information is made to all CMUs (CMU #1 to CMU #n) during the subsequent second transmission cycle. However, in this case, the CMU that failed to transmit may repeatedly fail, resulting in the low communication success rate in the prior art.

[0052] However, the wireless battery management system according to embodiments of this disclosure significantly improves the communication success rate by prioritizing requests to retransmit only from the CMU that failed to transmit during the second transmission cycle.

[0053] refer to Figure 2 and Figure 4 In step S230, when any CMU transmission fails, the BMU (130) preferentially requests transmission from the CMU that failed ( Figure 4 The CMU (Cell Monitoring Unit) in the system (CMU #2) retransmits cell monitoring information.

[0054] For example, BMU (130) broadcasts an advertising packet to all CMUs (120-1, 120-2, ..., 120-n) containing the identification information of the CMU that failed to transmit.

[0055] In this case, it is advantageous for the advertising packet to be of the ADV_IND packet type, which does not specify a particular device and can be received by all nearby devices, and the payload of the advertising packet includes the identification information of the CMU that failed to transmit.

[0056] According to one embodiment of this disclosure, the identification information of the CMU that failed to transmit can be implemented in the form of a flag. For example, if CMU #2 out of 16 CMUs (CMU #1, CMU #2, ..., CMU #16) fails to transmit, BMU (130) indicates this as "0000 0000 0000 0010", and if CMU #2, CMU #9 and CMU #16 fail to transmit, BMU (130) indicates this as "1000 0001 0000 0010", thereby notifying all CMUs (120-1, 120-2, ..., 120-n) of the CMU that failed to transmit.

[0057] Then, in step S240, the CMU that failed to transmit the cell monitoring information retransmits it to the BMU (130) during the second transmission cycle. If there are multiple CMUs that failed to transmit the information, each of the multiple CMUs that failed to transmit the information retransmits it to the BMU (130) during its own allocated time slot in the second transmission cycle based on the transmission priority.

[0058] Specifically, all CMUs (120-1, 120-2, ..., 120-n) receive advertising packets broadcast by BMU (130) and analyze the information included in the payload of the advertising packets to determine the CMUs that failed to transmit during the first transmission period.

[0059] The CMU that fails to transmit then checks all CMUs that have failed to transmit (including itself), determines the time slot allocated to that CMU in the second transmission cycle based on the transmission priority (i.e., the time slot allocated to itself during the second transmission cycle), and retransmits the cell monitoring information during that CMU's time slot.

[0060] For example, such as Figure 4 As shown, if only one CMU (CMU #2) fails to transmit, the transmission priority is meaningless, and CMU #2 will determine all time slots in the second transmission cycle as its own time slots, and repeatedly retransmit its cell monitoring information during all time slots of the second transmission cycle.

[0061] If CMU #2, CMU #9, and CMU #16 out of the 16 CMUs fail to transmit, then CMU #2, CMU #9, and CMU #16 each determine their own time slot based on transmission priority and transmit cell monitoring information during their own time slot in the second transmission cycle.

[0062] For example, if the transmission priority is set to CMU #2, CMU #9, and CMU #16, then CMU #2 is allocated 6 out of the 16 time slots in the second transmission cycle, and CMU #9 and CMU #16 are each allocated 5 time slots. Then, according to the preset transmission order algorithm, CMU #2 is retransmitted 6 times consecutively, CMU #9 is retransmitted 5 times consecutively, and CMU #16 is retransmitted 5 times consecutively, or CMU #2, CMU #9, and CMU #16 are each retransmitted 5 times sequentially, and finally CMU #2 is retransmitted 6 times.

[0063] According to an embodiment of this disclosure, time slots in the second transmission cycle are allocated based on the number of CMUs that failed to transmit and their transmission priority, thereby allocating time slots differentially to the multiple CMUs that failed to transmit.

[0064] Furthermore, the greater the transmission distance between the CMU and BMU, the higher the transmission priority can be set; or the higher the number of transmission failures of the corresponding CMU, the higher the transmission priority can be set. This allows higher transmission priority to be allocated to the CMU, which is more likely to fail, thereby improving the communication success rate.

[0065] In addition, if the number of retransmission failures of the CMU based on the transmission failure is equal to or greater than a preset threshold, the BMU (130) can diagnose the CMU as faulty and notify the user, thereby preventing potential safety incidents in advance.

[0066] As used in this disclosure (especially in the appended claims), unless the context clearly indicates otherwise, the terms “a” and “the” include both singular and plural indicators. Furthermore, it should be understood that any numerical range recited in this disclosure is intended to include all subranges contained therein (unless otherwise explicitly indicated), and therefore, the disclosed numerical range includes each individual value between the minimum and maximum values ​​of the numerical range.

[0067] Unless a specific order is described or otherwise specified, the steps constituting a method according to an embodiment of this disclosure may be performed in a suitable order. In other words, this disclosure is not necessarily limited to the order in which the steps are described. All examples or indicative terms (“e.g.,” “such as”) described in this disclosure are used only to describe this disclosure in more detail. Therefore, it should be understood that the scope of this disclosure is not limited to the exemplary embodiments described above or the use of such terms unless limited by the appended claims. Moreover, various modifications, combinations, and substitutions can be made within the scope of the appended claims or their equivalents, depending on design conditions and factors, and should be apparent to those skilled in the art.

[0068] Therefore, this disclosure is not limited to the embodiments described above, but is intended to include all modifications, equivalents and alternatives that fall within the spirit and scope of the appended claims.

Claims

1. A wireless battery management system, comprising: Multiple cell monitoring units (CMUs) are configured to monitor multiple battery cells; as well as The battery management unit (BMU) is configured to perform wireless communication with and manage the multiple CMUs. The BMU is also configured as follows: The request is to transmit cell monitoring information of the multiple battery cells from the multiple CMUs, and If the cell monitoring information transmission fails at at least one of the plurality of CMUs, a priority request is made to retransmit the cell monitoring information from the at least one CMU that failed to transmit.

2. The wireless battery management system according to claim 1, wherein: The BMU is also configured to broadcast an advertising packet requesting the transmission of the cell monitoring information to the plurality of CMUs; Each of the plurality of CMUs is configured to transmit the cell monitoring information to the BMU during the first transmission cycle; as well as Based on the failure of at least one CMU transmission, the BMU is further configured to broadcast an advertising packet including the identification information of the at least one CMU that failed to transmit, and the at least one CMU that failed to transmit is configured to retransmit the cell monitoring information to the BMU during a second transmission cycle.

3. The wireless battery management system according to claim 1, wherein: The BMU is also configured to broadcast an advertising packet requesting the transmission of the cell monitoring information to the plurality of CMUs; Each of the plurality of CMUs is configured to transmit the cell monitoring information to the BMU during the first transmission cycle; Based on the existence of two or more CMUs experiencing transmission failures, the BMU is also configured to broadcast advertising packets that include identification information of the two or more CMUs experiencing transmission failures. and Each of the two or more CMUs that failed to transmit is configured to retransmit the cell monitoring information to the BMU during the corresponding time slot of the second transmission cycle, wherein the corresponding time slot of the second transmission cycle is allocated to each of the two or more CMUs that failed to transmit based on transmission priority.

4. The wireless battery management system according to claim 3, wherein, The time slots of the second transmission cycle are differentiated and allocated to the two or more CMUs that have experienced transmission failures based on the transmission priority.

5. The wireless battery management system according to claim 3, wherein, The transmission priority is determined based on the transmission distance between the BMU and the corresponding CMU among the two or more CMUs.

6. The wireless battery management system according to claim 3, wherein, The transmission priority is determined based on the number of transmission failures of the corresponding CMU among the two or more CMUs.

7. The wireless battery management system according to claim 2, wherein, The advertising packet, which includes the identification information of the at least one CMU that has failed to transmit, includes an advertising indication (ADV_IND) packet.

8. The wireless battery management system according to claim 2, wherein, The advertising packet, which includes the identification information of the at least one CMU whose transmission failed, includes the identification information of the at least one CMU whose transmission failed in the form of a flag in its payload.

9. The wireless battery management system according to claim 2, wherein, The identification information of the at least one CMU that failed to transmit includes the node information of the at least one CMU that failed to transmit.

10. The wireless battery management system according to claim 1, wherein, The BMU is also configured to diagnose the at least one CMU that has failed to retransmit as a fault, based on the fact that the number of retransmission failures of the at least one CMU is equal to or greater than a preset threshold.

11. A method of operating a wireless battery management system, the method comprising: The Battery Management Unit (BMU) requests the transmission of cell monitoring information from multiple Cell Monitoring Units (CMUs). During the first transmission cycle, each of the multiple CMUs transmits the cell monitoring information to the BMU; If the BMU fails to transmit the cell monitoring information based on at least one CMU transmission failure, it shall first request the retransmission of the cell monitoring information from the at least one CMU that failed to transmit the information. as well as The cell monitoring information is retransmitted to the BMU by the at least one CMU that failed to transmit the data during the second transmission cycle.

12. The method according to claim 11, wherein: The request to transmit the cell monitoring information includes: The BMU broadcasts an advertising packet requesting the transmission of the cell monitoring information to the plurality of CMUs, and Priority requests to retransmit the cell monitoring information include: The BMU broadcasts an advertising packet, including identification information of at least one CMU that failed to transmit, to the plurality of CMUs.

13. The method according to claim 11, wherein, The request to transmit the cell monitoring information includes: The BMU broadcasts an advertising packet requesting the transmission of the cell monitoring information to the plurality of CMUs; and Based on the presence of two or more CMUs experiencing transmission failures, priority requests for retransmission of the cell monitoring information include: The BMU broadcasts an advertising packet, including identification information of two or more CMUs whose transmission failed, to the plurality of CMUs. The process of retransmitting the cell monitoring information to the BMU includes: each of the two or more CMUs that failed to transmit the cell monitoring information to the BMU during a corresponding time slot of the second transmission cycle, wherein the corresponding time slot of the second transmission cycle is set based on transmission priority.

14. The method according to claim 13, wherein, Based on the transmission priority, the time slots of the second transmission cycle are differentiatedly allocated to the two or more CMUs that have failed to transmit.

15. The method according to claim 13, wherein, The transmission priority is determined based on the transmission distance between the corresponding CMU and the BMU.

16. The method according to claim 13, wherein, The transmission priority is determined based on the number of transmission failures of the corresponding CMU.

17. The method according to claim 12, wherein, The advertising packet, which includes the identification information of the at least one CMU that has failed to transmit, includes an advertising indication (ADV_IND) packet.

18. The method according to claim 12, wherein, The advertising packet, which includes the identification information of the at least one CMU whose transmission failed, includes the identification information of the at least one CMU whose transmission failed in the form of a flag in its payload.

19. The method according to claim 12, wherein, The identification information of the at least one CMU that failed to transmit includes the node information of the at least one CMU that failed to transmit.

20. The method of claim 11, further comprising: The BMU diagnoses the at least one CMU that has failed to retransmit as a fault based on the number of retransmission failures of the at least one CMU being equal to or greater than a preset threshold.

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