CRITICAL BSS PARAMETER MANAGEMENT METHOD APPLICABLE TO MULTI-LINK AND RELATED APPARATUS.

Abstract

This application relates to the field of wireless communication, and in particular, to the method of managing critical BSS parameters applicable to multiple links and a related device, which are applied, for example, to a wireless local area network that supports the 802.11be standard. The method includes: A first AP in a first MLD AP generates and sends a first frame, where the first frame indicates update count values ​​for critical BSS parameters corresponding to a plurality of APs in the first MLD AP and update count values ​​for critical BSS parameters corresponding to a plurality of APs in a second MLD AP, and the second MLD AP is an MLD AP to which a non-transmitting AP belongs in a multiple BSSID set including the first AP.This helps some APs or all APs in some MLD APs to notify AP-managed STAs regarding whether critical BSS parameters of AP-managed BSS are up to date, to help STAs in receiving a latest critical BSS parameter.

Description

CRITICAL BSS PARAMETER MANAGEMENT METHOD APPLICABLE TO MULTI-LINK AND RELATED APPARATUS ML / 1 / ¿UZÓ / UÓUO4O FIELD OF INVENTION This application relates to the field of wireless communication technologies, and in particular, to a method of managing critical BSS parameters applicable to multiple links and a related device. BACKGROUND OF THE INVENTION To significantly increase the transmission speed of a wireless local area network (WLAN), orthogonal frequency division multiple access (OFDMA) technology is incorporated into the IEEE 802.11ax standard, building upon existing orthogonal frequency division multiplexing (OFDM) technology. OFDMA supports multiple nodes sending and receiving data simultaneously, achieving multi-station diversity gains. The next-generation Wi-Fi standard, IEEE 802.11be, is referred to as extremely high throughput (EHT) or Wi-Fi 7, and its primary goal is to significantly improve peak throughput. A WLAN device compliant with IEEE 802.11be can improve peak throughput and reduce service transmission latency by utilizing multiple streams (up to 16 spatial streams), multiple frequency bands (e.g., 2.4 GHz, 5 GHz, and 6 GHz), and multiple channels within the same frequency band. These multiple frequency bands or multiple channels can be collectively referred to as multiple links. A station device compliant with IEEE 802.11be that simultaneously supports multiple links is referred to as a multi-link device (MLD). When a BSS on an access point (AP) in a multi-link access point device (MLD AP) is updated, some multi-link station devices or stations may fail to obtain the latest BSS information managed by these APs. Consequently, these multi-link station devices or stations cannot communicate normally with these special APs. BRIEF DESCRIPTION OF THE INVENTION The modalities of this application provide a method for managing critical BSS parameters applicable to multiple links and related equipment, to help some or all APs In some MLDs, APs notify the managed STAs (managed BSS) if critical AP BSS parameters are updated, helping the STA receive the latest critical BSS parameter. Therefore, the STA can typically also communicate with the AP after the AP's critical BSS parameter is updated. The following describes this request from different perspectives. It should be understood that reference can be made to the following implementations and beneficial effects of the different aspects. According to the first aspect, this application provides a BSS parameter management method applicable to multiple links, applied to a first MLD AP, where a first AP is any reporting AP in the first MLD AP. The BSS parameter management method applicable to multiple links includes: The first AP in the first MLD AP generates a first frame and sends the first frame on a link on which the first AP operates. The first frame contains parameter update information for the critical BSS core service set corresponding to a plurality of APs in the first MLD AP and critical BSS parameter update information corresponding to a plurality of APs in a second MLD AP.The second MLD AP is an MLD AP to which an AP not broadcast belongs in a set of multiple BSSID core service set identifiers including the first AP, and a piece of critical BSS parameter update information corresponding to an AP is used to determine if a critical BSS parameter in a BSS managed by the AP is up to date. Optionally, the critical BSS parameter update information includes a critical BSS parameter update count value. Optionally, the critical BSS parameter update count value is incremented by 1 when one or more critical BSS parameter parameters change. In this solution, using the first box, not only are critical BSS parameter update count values ​​indicated for the plurality of APs in the first MLD AP, but also for the plurality of APs in the second MLD AP. This implements a mechanism where one AP assists a plurality of APs in another MLD AP in indicating corresponding critical BSS parameter update count values, so that a STA can compare a currently received critical BSS parameter update count value with a critical BSS parameter update count value received last time, and check if a critical BSS parameter is up to date.Therefore, the STA can be assisted in receiving a final critical BSS parameter, and a non-AP MLD associated with the second MLD AP can listen on a link where a non-transmitting AP is operating on the second MLD AP, and can also function normally. In other words, for the non-AP MLD, there can be more channels available. ML / 1 / ¿UZÓ / UÓUO4O to be listened to for selection. In 802.11be, it is possible that all or some of the APs in an MLD AP may be non-transmitting APs. Therefore, the solution provided in this modality of this request can resolve an issue where some non-transmitting APs cannot send a management box to notify that a critical BSS parameter is updated. Therefore, the integrity and diversity of a critical BSS parameter update indication can be improved. With reference to the first aspect, in a possible implementation, after the first AP in the first MLD AP sends the first frame, the method further includes: The first AP in the first MLD AP generates a second frame, where the second frame indicates critical BSS 10 parameters specific to a plurality of APs in the first MLD AP and critical BSS parameters specific to a plurality of APs in the second MLD AP; and sends the second frame on the link on which the first AP works. This solution can not only help some APs on another MLD AP to indicate whether a critical BSS parameter is up to date, but it also helps some APs on the other MLD AP to indicate a specific critical BSS parameter. This specific critical BSS parameter includes an element related to a channel change. This allows the non-AP MLD to know the channel change status of all APs on the MLD AP in real time when the non-AP MLD is listening on one or more links (not all links), so that the non-AP MLD can function normally. According to a second aspect, this application provides a BSS parameter management method applicable to multiple links, and the method is applied to a first STA. The first STA can be a single-link STA or a STA in a non-AP MLD. The first STA and a first AP operate on a single link. The BSS parameter management method applicable to multiple links includes: The first STA of the non-AP MLD receives a first frame 25 on a link on which the first STA operates, and determines, based on the first frame, whether critical BSS parameters of a plurality of BSS managed by a plurality of APs in an MLD AP associated with the first STA are up to date. The first frame indicates critical BSS parameter update information corresponding to a plurality of APs in the first MLD AP and critical BSS parameter update information corresponding to a plurality of APs in a second MLD AP.The second MLD AP is an MLD AP to which a non-broadcasting AP belongs in a multiple BSSID set, including the first AP. A piece of critical BSS parameter update information corresponding to an AP is used to determine if a critical BSS parameter in a BSS managed by the AP is up to date. It can be understood that, when the first STA is a STA in the non-AP MLD, the MLD AP associated with the first STA may be an MLD AP associated with the non-AP MLD including ML / 1 / ZUZÓ / UÓUO4O the first STA. Optionally, the critical BSS parameter update information includes a critical BSS parameter update count value. Optionally, the critical BSS parameter update count value is incremented by 1 when one or more critical BSS parameter parameters change. With reference to the second aspect, in a possible implementation, after the first STA of the non-AP MLD receives the first frame, the method further includes: The first STA of the non-AP MLD receives a second frame on a link on which the first STA works, where the second frame indicates critical BSS parameters specific to a plurality of APs in the first AP MLD and critical BSS parameters specific to a plurality of APs in the second AP MLD; and analyzes the second frame to obtain critical BSS parameters specific to a plurality of APs in an AP MLD associated with the non-AP MLD. According to a third aspect, this application provides a communication device. The communication device can be a first MLD AP or a chip in a first MLD AP, for example, a Wi-Fi chip, or it can be a first AP in a first MLD AP or a chip in a first AP, and includes: a processing unit, configured to generate a first frame, wherein the first frame indicates parameter update information of the critical BSS core services set respectively corresponding to a plurality of APs in a first MLD AP and critical BSS parameter update information respectively corresponding to a plurality of APs in a second MLD AP, the second MLD AP being an MLD AP to which a non-broadcast AP belongs in a set of multiple BSSID core service set identifiers including a first AP, and a piece of critical BSS parameter update information corresponding to an AP is used to determine if a parameter The critical BSS in an AP-managed BSS is up to date; and a transceiver unit, configured to send the first frame on a link on which the communication apparatus is working. Optionally, the critical BSS parameter update information includes a critical BSS parameter update count value. Optionally, the critical BSS parameter update count value is incremented by 1 when one or more critical BSS parameter parameters change. With reference to the third aspect, in a possible implementation, the processing unit is further configured to generate a second frame, where the second frame indicates specific critical BSS parameters of a plurality of APs in the first MLD AP and critical BSS parameters specific to a plurality of APs in the second MLD AP. The transceiver unit is further configured to send the second frame on a link in ML / 1 / ¿UZÓ / UÓUO4O which works the communication apparatus. According to a fourth aspect, this application provides a communication device. The communication device can be a first STA or a chip within a first STA, for example, a Wi-Fi chip. The first STA can be a single-link STA or an STA within a non-AP MLD. The communication device includes: a transceiver unit, configured to receive a first frame on a link on which the communication apparatus operates, wherein the first frame indicates critical BSS parameter update information respectively corresponding to a plurality of APs in the first MLD AP and critical BSS parameter update information respectively corresponding to a plurality of APs in a second MLD AP, the second MLD AP being an MLD AP to which a non-transmitting AP belongs in a multiple BSSID set including the first AP, and a piece of critical BSS parameter update information corresponding to an AP is used to determine whether a critical BSS parameter in a BSS managed by the AP is updated; and a processing unit, configured to determine, based on the first frame, whether critical BSS parameters of a plurality of BSSs managed by a plurality of APs in an MLD AP associated with the communication apparatus are updated. Optionally, the critical BSS parameter update information includes a critical BSS parameter update count value. Optionally, the critical BSS parameter update count value is incremented by 1 when one or more critical BSS parameter parameters change. With regard to the fourth aspect, in a possible implementation, the transceiver unit is further configured to receive a second frame on a link where the communication device operates. This second frame indicates critical BSS parameters specific to a plurality of APs in the first MLD AP and critical BSS parameters specific to a plurality of APs in the second MLD AP. The processing unit is configured to analyze the second frame to obtain critical BSS parameters specific to a plurality of APs in an MLD AP associated with the non-AP MLD. In any implementation of the above, the first box includes a link identifier field and a multi-link device identifier (MLD) field. The link identifier field indicates a reported AP. The MLD identifier field indicates an MLD AP, including the reported AP. Optionally, the first box also includes a critical BSS parameter count field, and the critical BSS parameter update count value field indicates the critical BSS parameter update count value. In an implementation of any of the above aspects, the critical BSS parameter update count value field, the link identifier field, and the ML / 1 / ZUZÓ / UÓUO4O MLD identifier field are carried in a reduced neighbor report element RNR of the first frame. It can be understood that the three fields—the critical BSS parameter update count value field, the link identifier field, and the MLD 5 identifier field—are independent, and all of them can be carried in the RNR element, or they may not all be carried in the RNR element. In other words, the RNR element can carry some of the three fields. In any of the above implementations, a TBTT target beacon transmission time information field in the RNR element carries a critical BSS parameter update count value, a link identifier field, and an MLD identifier field. A TBTT identifier field corresponds to an AP. In an implementation of any of the above aspects, a value of a short service set identifier field SSID of an AP in the RNR element is obtained based on an SSID of an MLD including the AP. In an implementation of any of the above aspects, a critical BSS parameter specific to an AP in the second box includes one or more of the following: an inclusion of a channel change advertisement element, an inclusion of an extended channel change advertisement element, an inclusion of a 20 wideband channel change element, and an inclusion of a channel change wrapper element. In an implementation of any of the above aspects, the specific critical BSS parameter above is carried in a multi-link ML element. According to a fifth aspect, this request provides a method for updating a critical BSS parameter, applied to a first MLD AP, where a second AP is any AP within the first MLD AP. The method for updating the critical BSS parameter includes: The second AP within the first MLD AP generates a second frame and sends the second frame over a link on which the second AP operates. The second frame indicates critical BSS parameters specific to a plurality of APs within the first MLD AP and / or critical BSS parameters specific to a plurality of APs within the second MLD AP. The second MLD AP is an MLD AP to which a non-transmitting AP belongs in a multiple BSSID set, including the second AP. Optionally, a critical BSS parameter specific to an AP in the second box includes one or more of the following: an inclusion of a channel change advertisement element, an inclusion of an extended channel change advertisement element, an inclusion of a wideband channel change advertisement element, and an inclusion of a 35-channel change wrapper element. Optionally, the specific critical BSS parameter is carried in a multiML element t / ¿UZÓ / UÓUO4O ML link. According to a sixth aspect, this request provides a method for updating a critical BSS parameter, applied to a second STA, where the second STA can be a single-link STA, or it can be an STA in a non-AP MLD. The second STA and a second APs operate on a link. The method for updating the critical BSS parameter includes: The second STA receives a second frame on a link on which the second STA operates and analyzes the second frame to obtain critical BSS parameters specific to a plurality of APs in an MLD AP associated with the second STA. The second frame indicates critical BSS parameters specific to a plurality of APs in the first MLD AP and / or critical BSS parameters specific to a plurality of APs in the second MLD AP. The second MLD AP is an MLD AP to which a non-transmitting AP belongs in a multiple BSSID set including the second AP. It can be understood that when the second STA is an STA in the non-AP MLD, the AP MLD associated with the second STA can be an AP MLD associated with the non-AP MLD including the second STA. Optionally, a critical BSS parameter specific to an AP in the second box includes one or more of the following: an inclusion of a channel change advertisement element, an inclusion of an extended channel change advertisement element, an inclusion of a wideband channel change advertisement element, and an inclusion of a 20-channel change wrapper element. Optionally, the specific critical BSS parameter is carried in a multilink ML element. According to a seventh aspect, this application provides a communication device. The communication device can be a first MLD AP or a chip in a first An MLD AP, for example, is a Wi-Fi chip, or it can be a second AP in a first MLDAP or a chip in a second AP, and includes: a processing unit, configured to generate a second frame, where the second frame indicates critical BSS parameters specific to a plurality of APs in the first MLD AP and / or critical BSS parameters specific to a plurality of APs in the second MLD AP, and the second MLD AP is an MLD AP to which belongs an AP not transmitting in a multiple BSSID set including the second AP; and a transceiver unit, configured to send the second frame on a link on which the communication apparatus works. Optionally, a critical BSS parameter specific to an AP in the second box includes one or more of the following: an inclusion of a 35-channel switch advertisement element, an inclusion of an extended channel switch advertisement element, an inclusion of a wideband channel switch advertisement element, and an inclusion of a channel switch wrapper element. Optionally, the specific critical BSS parameter is carried in a multilink ML element. According to an eighth aspect, this application provides a communication device. The communication device can be a second STA or a chip in a second STA, for example, a Wi-Fi chip. The first STA can be a single-link STA, or it can be an STA in a non-AP MLD. The communication device includes: a transceiver unit, configured to receive a second frame on a link on which the communication apparatus operates, wherein the second frame indicates critical BSS parameters specific to a plurality of APs in the first MLD AP and / or critical BSS parameters specific to a plurality of APs in the second MLD AP, and the second MLD AP is an MLD AP to which a non-transmitting AP belongs in a multiple BSSID set including the second AP; and a processing unit, configured to analyze the second frame to obtain critical BSS parameters specific to a plurality of APs in an MLD AP associated with the non-AP MLD. Optionally, a critical BSS parameter specific to an AP in the second box includes one or more of the following: an inclusion of a channel change advertisement element, an inclusion of an extended channel change advertisement element, an inclusion of a wideband channel change advertisement element, and an inclusion of a 20-channel change wrapper element. Optionally, the specific critical BSS parameter is carried in a multilink ML element. According to a ninth aspect, this application provides a communication apparatus. The communication apparatus is specifically a first MLD AP or a first 25 AP within a first MLD AP, and includes a processor and a transceiver. The processor is configured to support the first MLD AP in performing a corresponding function as described in the first aspect. The transceiver is configured to support communication between the first MLD AP and a non-access point multi-link device (also referred to as a station multi-link device), and to send information, a frame, a data packet, instructions, or the like, as described in the previous method, to the station multi-link device. The first MLD AP may further include a memory. The memory is configured to be coupled to the processor, and the memory stores program instructions and data required by the first MLD AP. Specifically, the processor is configured to generate a first frame, where 35 the first frame indicates parameter update information of the critical BSS core services set respectively corresponding to a plurality of APs in a first MLD ML / 1 / ZUZÓ / UÓUO4O AP and critical BSS parameter update information corresponding to a plurality of APs in a second MLD AP. The second MLD AP is an MLD AP to which an AP not transmitting in a set of multiple Basic Service Set Identifiers (BSSIDs) belongs, including a first AP, and a piece of critical BSS parameter update information corresponding to an AP is used to determine if a critical BSS parameter in a BSS managed by the AP is up to date. The transceiver is configured to send the first frame on a link on which the communication appliance is operating. According to a tenth aspect, this application provides a communication apparatus. The communication apparatus is specifically a first STA, including a processor and a transceiver. The processor is configured to support the first STA in performing a corresponding function as described in the second aspect. The transceiver is configured to support communication between the first STA and a first MLD AP, and to receive information, frames, data packets, instructions, and the like from the first MLD AP, as described in the previous method. The first STA may also include a memory. The memory is configured to be coupled to the processor, and it stores program instructions and data required by the first STA. Specifically, the transceiver is configured to receive a first frame on a link on which the communication apparatus operates, where the first frame indicates critical BSS parameter update information respectively corresponding to a plurality of AP in the first MLD AP and critical BSS parameter update information corresponding to a plurality of APs in a second MLD AP. The second MLD AP is an MLD AP to which a non-transmitting AP belongs in a multiple BSSID set, including the first AP, and a piece of critical BSS parameter update information corresponding to an AP is used to determine if a critical BSS parameter in a BSS managed by the AP is updated. The processor is configured to determine, based on the first frame, whether critical BSS parameters of a plurality of BSSs managed by a plurality of APs in an MLD AP associated with the first STA are updated. According to an eleventh aspect, this application provides a communication device. The communication device is specifically a first MLD AP or a second The first MLD AP is a multi-link access point (MLD AP) and includes a processor and a transceiver. The processor is configured to support the first MLD AP in performing a corresponding function as described in the fifth aspect. The transceiver is configured to support communication between the first MLD AP and a non-access point multi-link device (also referred to as a station multi-link device), and to send information, a frame, a data packet, instructions, or similar data as described in the preceding method to the station multi-link device. The first MLD AP may also include memory. The memory is configured to be ML / 1 / ¿UZÓ / UÓUO4O coupled to the processor, and the memory stores program instructions and data that are necessary for the first MLD AP. Specifically, the processor is configured to generate a second frame, where the second frame indicates critical BSS parameters specific to a plurality of APs in the first MLD AP and / or critical BSS parameters specific to a plurality of APs in the second MLD AP. The second MLD AP is an MLD AP to which an AP not transmitting in a multiple BSSID set belongs, including the second AP. The transceiver is configured to send the second frame on a link on which the communication device is operating. According to the twelfth aspect, this application provides a communication apparatus. The communication apparatus is specifically a second STA, including a processor and a transceiver. The processor is configured to support the second STA in performing a corresponding function as described in the sixth aspect. The transceiver is configured to support communication between the second STA and a first MLD AP, and to receive information, frames, data packets, instructions, and the like from the first MLD AP, as described in the previous method. The second STA may also include a memory. The memory is configured to be coupled to the processor, and it stores program instructions and data required by the second STA. Specifically, the transceiver is configured to receive a second frame on a link where the communication device is operating. This second frame contains critical BSS parameters specific to a plurality of access points (APs) on the first multi-level distributed access point (MLDAP) and / or critical BSS parameters specific to a plurality of APs on the second MLDAP. The second MLDAP is an MLDAP to which an AP not transmitting belongs within a multiple BSSID set, including the second AP. The processor is configured to analyze the second frame to obtain critical BSS parameters specific to a plurality of APs on an MLDAP associated with the second STA. According to a thirteenth aspect, this application provides a chip or system-on-a-chip, including an input / output interface and a processing circuit. Specifically, the processing circuit is configured to generate a first frame, where the first frame indicates critical BSS parameter update information corresponding to a plurality of APs in a first MLD AP and critical BSS parameter update information corresponding to a plurality of APs in a second MLD AP. The second MLD AP is an MLD AP to which a non-broadcasting AP belongs in a set of multiple BSSIDs, including a first AP, and a piece of critical BSS parameter update information corresponding to an AP is used to determine whether a critical BSS parameter in a BSS managed by the AP is up to date. The interface of ML / 1 / ZUZÓ / UÓUO4O input / output is configured to send the first frame on a link on which the chip or system-on-chip is working. In a possible design, the input / output interface is configured to receive a first frame on a link where the chip or system-on-a-chip operates. This first frame contains critical BSS parameter update information corresponding to a plurality of APs in the first MLD AP and critical BSS parameter update information corresponding to a plurality of APs in a second MLDAP. The second MLD AP is an MLDAP to which an AP not transmitting belongs within a set of multiple BSSIDs, including the first AP. A piece of critical BSS parameter update information corresponding to an AP is used to determine whether a critical BSS parameter in a BSS managed by the AP is up to date.The processing circuit is configured to determine, based on the first frame, whether critical BSS parameters of a plurality of BSS managed by a plurality of APs in an MLD AP associated with a first STA are up to date. According to a fourteenth aspect, this application provides a chip or system-on-a-chip, including an input / output interface and a processing circuit. The processing circuit is configured to generate a second frame, where the second frame indicates critical BSS parameters specific to a plurality of APs in the first MLD AP and / or critical BSS parameters specific to a plurality of APs in the second MLD AP. The second MLDAP is an MLDAP to which an AP not transmitting belongs in a multiple BSSID set, including the second AP. The input / output interface is configured to send the second frame on a link on which the chip or system-on-a-chip operates. In a possible design, the input / output interface is configured to receive a second frame on a link where the chip or system-on-a-chip operates. This second frame indicates critical BSS parameters specific to a plurality of APs in the first MLD AP and / or critical BSS parameters specific to a plurality of APs in the second MLDAP. The second MLDAP is an MLDAP to which an untransmitted AP belongs within a multiple BSSID set, including the second AP. The processing circuitry is configured to analyze the second frame to obtain critical BSS parameters specific to a plurality of APs in an MLD AP associated with the second STA. According to the fifteenth aspect, this application provides a computer-readable storage medium. The computer-readable storage medium stores instructions. When the instructions are executed on a computer, the computer is enabled to execute the critical BSS parameter management method applicable to multiple links according to either the first or second aspect. According to the sixteenth aspect, this request provides a computer-readable storage medium. The computer-readable storage medium stores instructions. When the instructions are executed on a computer, the computer is enabled to execute the method to update a critical BSS parameter according to the fifth or sixth aspect. According to the seventeenth aspect, this application provides a computer program product, including instructions. When the computer program product runs on a computer, the computer executes the critical BSS parameter management method applicable to multiple links according to either the first or second aspect. According to the eighteenth aspect, this request provides a computer program product, including instructions. When the computer program product runs on a computer, the computer executes the method to update a critical BSS parameter according to the fifth or sixth aspect. Implementing certain modes of this request can help some or all APs in some MLD APs to notify the STAs managed by the APs regarding whether critical AP BSS parameters (managed BSS) are up to date, thus helping the STAs receive the latest critical BSS parameters. Therefore, after the AP's critical BSS parameters are updated, the STA can also communicate with the AP. BRIEF DESCRIPTION OF THE FIGURES To describe the technical solutions in modalities of this application more clearly, the following briefly describes the accompanying drawings used to describe modalities. FIGURE 1 is a schematic diagram of an AP MLD structure and a non-AP MLD structure according to one modality of this application; FIGURE 2 is a schematic diagram of a box format of a multiple BSSID element according to a modality of this application; FIGURE 3A is a schematic diagram of a communication system structure 100 according to one modality of this application; FIGURE 3B is a schematic diagram of a communication system structure 200 according to one modality of this application; FIGURE 3C is a schematic diagram of a communication system structure 300 according to one modality of this application; FIGURE 4 is a schematic architectural diagram of a multiple BSSID set according to a modality of this application; FIGURE 5 is a schematic diagram of a frame structure of a frame ML / 1 / ¿UZÓ / UÓUO4O TIM in accordance with a modality of this request; FIGURE 6 is a schematic diagram of a management chart structure according to one modality of this application; FIGURE 7 is a schematic flowchart of a critical BSS parameter management method applicable to multiple links according to one modality of this application; FIGURE8A is a schematic diagram of a frame structure of an RNR element according to one modality of this application; FIGURE 8B is a schematic diagram of a box structure of a TBTT identifier field in an RNR element according to a modality of this request; FIGURE 9 is a schematic flowchart of a method for updating a critical BSS parameter according to one modality of this request; FIGURE 10A is a schematic diagram of a frame structure of an ML element according to one modality of this application; FIGURE 10B is a schematic diagram of a first part of a box structure of an ML element according to one modality of this request; FIGURE 11A is a schematic diagram of a box structure of an inclusion of a channel change announcement element according to a modality of this ML t / ¿UZÓ / UÓUO4O request; FIGURE 11B is a schematic diagram of a box structure of an inclusion of an extended channel change advertisement element according to a modality of this application; FIGURE 11C is a schematic diagram of a box structure of an inclusion of a wideband channel switching element according to a modality of this application; FIGURE 11D is a schematic diagram of a Quiet Element box structure according to one modality of this application; FIGURE 12 is a schematic diagram of a non-inherited item frame structure according to one modality of this application; FIGURE 13 is a schematic diagram of a communication structure 1 according to one modality of this request; FIGURE 14 is a schematic diagram of a communication structure 2 according to one modality of this request; of a device of FIGURE 15 is a schematic diagram of a communication structure 3 according to one modality of this request; of a device FIGURE 16 is a schematic diagram of a communication apparatus structure 4 according to one modality of this application; and FIGURE 17 is a schematic diagram of a communication apparatus structure 1000 according to one modality of this application. DETAILED DESCRIPTION OF THE INVENTION The following clearly describes the technical solutions in the forms of this application with reference to the accompanying drawings in the forms of this application. To better understand a method for managing critical BSS parameters applicable to multiple links and a related apparatus disclosed in modalities of this application, related concepts are first described in modalities of this application. 1. Multi-link device A wireless communication system applicable to the modalities of this application can be a wireless local area network (WLAN) or a cellular network. A unicast service indication method can be implemented by a communication device in the wireless communication system or by a chip or processor within the communication device. The communication device can be a wireless communication device that supports concurrent transmission over multiple links. For example, the communication device is referred to as a multi-link device or a multi-band device. Compared to a device that supports only single-link transmission, the multi-link device has higher transmission efficiency and superior throughput. The multi-link device includes one or more affiliate stations (affiliate STAs). Affiliate stations are logical stations and can operate on a link. An affiliate station can be an access point (AP) or a non-access point station (non-AP STA). For ease of description, in this application, a multi-link device whose affiliate station is an AP may be referred to as a multi-link AP, a multi-link AP device, or a multi-link AP device (MLD AP), and a multi-link device whose affiliate station is a non-AP STA may be referred to as a non-AP multi-link device, a non-AP multi-link device, or a non-AP multi-link device (MLD no-AP).For ease of description, the multi-link device including an affiliated station is also briefly described as the multi-link device including a station in the modalities of this application. A multi-link device includes one or more affiliated stations (STAs). In other words, a multi-link device can include a plurality of logical stations. Each logical station operates on a link, but a plurality of logical stations can operate on the same link. The multi-link device can implement wireless communication according to the 802.11 standard family. For example, a station that meets a performance ML / 1 / ¿UZÓ / UÓUO4O extremely high throughput (EHT), or a station that complies with or supports 802.11be, implements communication with another device. This other device may or may not be a multi-link device. For example, the multi-link device in the modalities of this application may be a single-antenna device, or it may be a multi-antenna device. For example, the multi-link device may have more than two antennas. The number of antennas included in the multi-link device is not limited in this modality of the application. In the modalities of this application, the multi-link device may allow 10 services of the same access type to be transmitted over different links, or it may even allow the same data packets to be transmitted over different links. Alternatively, the multi-link device may not allow services of the same access type to be transmitted over different links, but it may allow services of different access types to be transmitted over different links. For example, a multi-link device is a device with wireless communication capabilities. This device can be part of a complete system, or it can be a chip, processing unit, or similar component installed within the complete system. The device in which the chip or processing unit is installed can be controlled by the chip or processing unit to implement the methods and functions described in this application. For example, a non-AP MLD in this application functions as a wireless transceiver, supports 802.11 serial protocols, and can communicate with an AP MLD, another non-AP MLD, or a single-link device. A non-AP MLD is any user communication device that allows a user to communicate with an access point (AP) and also with a wireless LAN (WLAN).For example, a non-AP MLD can be user equipment that can be connected to a network, such as a tablet computer, desktop computer, laptop computer, notebook computer, ultra-mobile personal computer (UMPC), handheld computer, netbook, personal digital assistant (PDA), or mobile phone; it can be an Internet of Things node in an Internet of Things; or it can be a vehicle-mounted communication device in an Internet of Vehicles. Alternatively, a non-AP MLD can be a chip and processing system in the aforementioned terminals. The MLD AP in the modalities of this application is an appliance that serves the non-AP MLD and can support the 802.11 serial protocols. For example, the MLD AP may be a communication entity such as a communication server, router, switch, or bridge, or the MLD AP may include various forms of macro base stations, micro base stations, and ML t / ¿UZÓ / UÓUO4O relay stations. Certainly, the MLD AP can alternatively be a chip and a processing system in various processing forms, to implement the method and function in the modalities of this application. In addition, the multi-link device can support high-rate and low-latency transmission. With the continuous evolution of wireless local area network application scenarios, the multi-link device can be used in additional scenarios.For example, the multi-link device serves as a sensor node (e.g., a smart water meter, a smart electricity meter, or a smart air sensing node) in a smart city, a smart device (e.g., a smart camera, a projector, a display screen, a television, a stereo, a refrigerator, or a washing machine) in a smart home, a node in the Internet of Things, an entertainment terminal (e.g., AR, VR, or another wearable device), a smart device (e.g., a printer, or a projector) in a smart office, an Internet of Vehicles device in the Internet of Vehicles, or infrastructure (e.g., a vending machine, a self-service navigation console, a self-checkout device, or a self-service food machine) in everyday life scenarios.Specific forms of non-AP MLDs and AP MLDs are not specifically limited to the modalities of this application and are merely examples for the purposes of this description. The 802.11 protocol may be a protocol that supports 802.11be or is compatible with 802.11be. Frequency bands in which the multi-link device operates may include, but are not limited to, sub-1 GHz, 2.4 GHz, 5 GHz, 6 GHz, and a high frequency of 60 GHz. For example, the multi-link device in the modalities of this application can be a single-antenna device or a multi-antenna device. For example, the multi-link device in this modality of this application can be a device with at least two antennas. The number of antennas included in the multi-link device is not limited in this modality of this application. Figure 1 is a schematic diagram of an MLD AP structure and a non-AP MLD structure according to one modality of this application. Figure 1 is a schematic diagram of a structure in which the MLD AP has a plurality of antennas and a structure in which the non-AP MLD has a single antenna. The 802.11 standard focuses on the Physical Layer (PHY) and Medium Access Control (MAC) layers in the MLD AP and the non-AP MLD. 2. Link identifier A link identifier represents a station operating on a link. In other words, if there is more than one station on a link, more than one link identifier represents more than one station. A link mentioned below sometimes also represents a station operating on the link. ML / 1 / ¿UZÓ / UÓUO4O During data transmission, an MLD AP and a non-AP MLD can use a link identifier to identify a link or a station on a link. Before communication, the MLD AP and the non-AP MLD first negotiate or communicate with each other to establish a mapping between a link identifier and a link or station on a link. Therefore, during data transmission, a link identifier is used to indicate a link or station on a link, so that the transmission of a large amount of signaling information is not required to indicate the link or station on the link. This reduces signaling overhead and improves transmission efficiency. In one example, a management frame sent by the MLD AP when a basic service set (BSS), such as a beacon frame, is established, carries an element, and this element includes multiple link identification information fields. The link identifier information field can indicate a correspondence between a link identifier and a station operating on a link corresponding to that link identifier. The link identification information field not only includes the link identifier but also one or more pieces of the following information: a medium access control (MAC) address, an operational class, and a channel number. One or more of the MAC address, operational class, and channel number can indicate a link.For the AP, the AP's MAC address is also a BSSID (Basic Service Set Identifier). In another example, during a multi-link device association process, an AP MLD and a non-AP MLD negotiate multi-link identification information fields. Multi-link device association means that an AP in the AP MLD is associated with a STA in the non-AP MLD once. This association can allow multiple STAs in the non-AP MLD to be separately associated with multiple APs in the AP MLD, where each STA is associated with one AP. In subsequent communication, the MLD AP or the non-AP MLD represents a station on the non-AP MLD using a link identifier. This link identifier may also represent one or more attributes of the station's MAC address, operational class, or channel number. The MAC address may be replaced with an association identifier of the MLD AP after association. Optionally, if multiple stations operate on a link, the meanings identified by a link identifier (which is a numeric ID) include not only an operational class comprising the link and a channel number, but also an identifier of a station operating on the link, such as a station's MAC address or association identifier (AID). 3. Multiple Basic Service Set Identifier (Multiple BSSID Set) A set of multiple basic service set identifiers (BSSID set A multiple BSSID set (ML / 1 / ZUZÓ / UÓUO4O, which can be referred to as a multiple BSSID set) can be understood as a set of several cooperative APs. All cooperative APs use the same operating channel number and antenna interface. In the multiple BSSID set, only one AP transmits a BSSID, and all other APs are non-transmitted BSSIDs. Information regarding a multiple BSSID set (i.e., a multiple BSSID element) is carried in a radio beacon chart, a probe response chart, or a neighbor report sent by an AP with a transmitted BSSID. Information regarding the BSSID of the AP with the non-transmitted BSSID is derived by the station using the radio beacon chart, probe response chart, the multiple BSSID element in a neighbor report, or similar means.The AP BSSID with the non-broadcast BSSID is calculated based on an AP BSSID that broadcasts the BSSID and a BSSID index field IN A multiple BSSID index element in a non-broadcast BSSID profile; for details, refer to Version 802.11 REVmd_D3.0. The multiple BSSID set can also be understood as including a plurality of APs. Each AP manages a BSS, and different APs can have different SSIDs and permissions, for example, a security mechanism or a broadcast opportunity. In a multiple BSSID set, only an AP whose BSSID is a transmitted BSSID can send a beacon frame and a probe response frame, and an AP whose BSSID is a non-transmitted BSSID cannot send a beacon frame. Therefore, if a probe request frame sent by an STA is sent to an AP whose BSSID is a non-transmitted BSSID in the multiple BSSID set, the AP whose BSSID is a transmitted BSSID in the multiple BSSID set will assist in responding to the probe response frame. In a plurality of APs in the multiple BSSID set, one AP's BSSID is configured as a Transmitted BSSID, an AP with a Transmitted BSSID can be referred to as a Transmitted AP, the BSSIDs of other APs are configured as Nontransmitted BSSIDs, and an AP with a Nontransmitted BSSID can be referred to as a Nontransmitted AP. The radio beacon frame sent by the transmitting AP may include a multiple BSSID element. A format for the multiple BSSID element frame is shown in Figure 2. Figure 2 is a schematic diagram of a multiple BSSID element frame format according to one modality of this application. The multiple BSSID element includes an element ID field, a length field, a maximum BSSID indication field, and an optional sub-element field. The maximum BSSID indication field indicates a maximum number N of BSSIDs included in the multiple BSSID set, and an optional sub-element field includes information regarding a BSSID of an AP with a non-transmitted BSSID. ML / 1 / ¿UZÓ / UÓUO4O The maximum number of APs allowed in the multiple BSSID set is 2^n, where n is a value indicated by a MaxBSSID Indicator field in the multiple BSSID element shown in Figure 2, and N = 2^n. Therefore, bits 1 through 2^n-1 of a Service Indication virtual bitmap field can be assigned to APs in non-broadcast BSSIDs in the multiple BSSID set to indicate whether APs in non-broadcast BSSIDs with NoTxBSS IDs (identifiers) 1 through 2^n-1 have multicast service. A NoTxBSS ID value is equal to a value in a BSSID Index field in a Multiple BSSID Index element in a non-broadcast BSSID profile in the multiple BSSID element. The non-broadcast BSSID profile is in an optional sub-element field. 4. Critical BSS Parameter For example, a critical BSS parameter may include one or more of the following: an inclusion of a Channel Switch Announcement element, an inclusion of an Extended Channel Switch Announcement element, a modification of the EDCA parameters element, an inclusion of a Quiet element, a modification of the DSSS Parameter Set, a modification of the CF Parameter Set element, a modification of the HT Operation element, or an inclusion of a Wide Bandwidth Channel Switch element.an inclusion of a Channel Switch Wrapper element, an inclusion of an Operating Mode Notification element, an inclusion of a Quiet Channel element, a modification of the VHT (Very High Performance) Operation element, a modification of the HE (High Efficiency) Operation element, an insertion of a Broadcast TWT element, an inclusion of the BSS Color Change Announcement element, a modification of the MU EDCA Parameter Set element.and a modification of the Spatial Reuse Parameter Set element. One or more of the above critical BSS parameters may also be listed as the critical parameter of the link. 5. Specific critical BSS parameter A specific critical BSS parameter can refer to a parameter related to a channel change within critical BSS parameters. Specifically, the critical BSS parameter ML / 1 / ¿UZÓ / UÓUO4O specifically includes one or more of the following: an inclusion of a Channel Switch Announcement element, an inclusion of an Extended Channel Switch Announcement element, an inclusion of a Wide Bandwidth Channel Switch element, and an inclusion of a Channel Switch Wrapper element. Although the modalities of this application are mainly described using a network in which an IEEE 802.11 is deployed as an example, a person skilled in the art readily understands that several aspects of this application can be extended to other networks using various standards or protocols, for example, BLUETOOTH (Bluetooth), a high performance radio LAN (HIPERLAN) (a wireless standard that is similar to the IEEE 802.11 standard, and is mainly used in Europe), a wide area network (WAN), a wireless local area network (WLAN), a personal area network (PAN), or other known or later developed networks. Therefore, the various aspects provided in this application are applicable to any convenient wireless network regardless of coverage and wireless access protocol. Figure 3A is a schematic diagram of a communication system 100 structure according to one modality of this application. In Figure 3A, a wireless local area network is used as an example to describe the communication system 100 to which one modality of this application applies. The communication system 100 includes a station 101 and a station 102. Station 101 can communicate with station 102 through multiple links to improve performance. Station 101 can be a multi-link device, and station 102 can be a single-link device, a multi-link device, or similar. In one scenario, station 101 is a In one scenario, station 101 is a non-AP MLD, and station 102 is either a non-AP MLD or a station (e.g., a single-link station). In another scenario, station 101 is a non-AP MLD, and station 102 is either an AP (e.g., a single-link AP) or an MLD AP. In yet another scenario, station 101 is an MLD AP, and station 102 is either an MLD AP or an AP. In yet another scenario, station 101 is a non-AP MLD, and station 102 is either a non-AP MLD or a STA (e.g., a single-link station). Certainly, the wireless local area network may also include other devices. The number and type of devices shown in Figure 3A are merely examples. Figure 3B is a schematic diagram of a communication system structure 200 according to one modality of this application. Figure 3C is a schematic diagram of a communication system structure 300 according to one modality of this application. Figure 3B and Figure 3C show respectively ML / 1 / ¿UZÓ / UÓUO4O Schematic diagrams of communication system 200 and communication system 300 structures. In communication system 200 and communication system 300, for example, a multi-link device in a wireless local area network communicates with another device through multiple links. Specifically, FIGURE 3B shows a scenario in which an AP MLD and a non-AP MLD communicate with each other. The AP MLD includes an affiliated AP 1 and an affiliated AP 2, and the non-AP MLD includes an STA 1 and an STA 2 to which the non-AP MLD belongs. Furthermore, the AP MLD and the non-AP MLD communicate in parallel via link 1 and link 2. FIGURE 3C shows a scenario in which an MLD AP 601 communicates with a MLD no-AP 602, MLD no-AP 603, and STA 604. MLD AP 601 includes an AP affiliated with AP 6011 and an AP affiliated with AP 601-3. MLD no-AP 602 includes three affiliated STAs: STA 602-1, STA 602-2, and STA 602-3. MLD no-AP 603 includes two affiliated STAs: STA 603-1 and STA 603-2. STA 604-1 and STA 604 are single-link devices. MLD AP 601 can communicate separately with MLD no-AP 602 via link 1, link 2, and a link 3. It can communicate with the non-AP MLD 603 via link 2 and link 3, and with STA 604 via link 1. In one example, STA 604 operates in the 2.4 GHz frequency band. In the non-AP MLD 603, STA 603-1 operates in the 5 GHz frequency band, and STA 603-2 operates in the 6 GHz frequency band. In the non-AP MLD 602, STA 602-1 operates in the 2.4 GHz frequency band, STA 602-2 operates in the 5 GHz frequency band, and STA 602-3 operates in the 6 GHz frequency band. AP 601-1, located in the AP MLD 601 and operating in the 2.4 GHz frequency band, can transmit uplink data. or downlink to STA 604 and STA 602-1 on the non-AP MLD 602 ​​via link 1.AP 601-2, located in MLD AP 601 and operating in the 5 GHz frequency band, can transmit uplink or downlink data to STA 603-1, located in non-AP MLD 603 and operating in the 5 GHz frequency band, via link 2. It can also transmit uplink and downlink data to STA 602-2, located in non-AP MLD 602 ​​and operating in the 5 GHz frequency band, via link 2. AP 601-3, located in MLD AP 601 and operating in the 6 GHz frequency band, can transmit uplink or downlink data to STA 602-3, located in non-AP MLD 602 ​​and operating in the 6 GHz frequency band, via link 3. It can also transmit uplink and downlink data to STA 603-2. MLD no-AP via link 3. It can be understood that FIGURE 3B shows only that the MLD AP supports two frequency bands, and FIGURE 3C shows only that the MLD AP 601 supports three frequency bands (2.4 GHz, 5 GHz, and 6 GHz). Each frequency band corresponds to a ML / 1 / ¿UZÓ / UÓUO4O link. For example, the MLD AP 601 can operate on one or more links of link 1, link 2, or link 3. On the AP side or the STA side, the link here can also be understood as a station operating on the link. In actual application, the MLD AP and the non-AP MLD can also support a greater or lesser number of frequency bands. In other words, the MLD AP and the non-AP MLD can operate on more or fewer links. This is not limited in this application. Figure 4 is a schematic architectural diagram of a multiple BSSID set according to one modality of this application. Specifically, an MLD for each AP shown in Figure 4 is a collocated MLDAP set. BSSID-1x, BSSID-1y, BSSID-2X, BSSID-2y, BSSID-2Z, BSSID-4X, BSSID-4y, BSSID-4z, BSSID-3, and BSSID-5 are MAC address identifiers, respectively, and are used to identify corresponding access points (APs). An AP whose MAC address identifier ends with 'x' is assumed to be a broadcast BSSID, an AP whose MAC address identifier ends with 'yoz' is a non-broadcast BSSID, and an AP whose MAC address identifier ends with only one digit is a common AP. A common AP is defined as an AP that does not belong to the multiple BSSID set. For example, a broadcast BSSID AP in a multiple BSSID set 1 is an AP with the MAC address identifier BSSID_1x. An AP BSSID not broadcast in multiple BSSID set 1 is an AP 1y whose MAC address identifier is BSSID_1y. An AP BSSID broadcast in multiple BSSID set 2 is an AP 2x whose MAC address identifier is BSSID_2x.An AP BSSID not broadcast in multiple BSSID set 2 includes an AP 2y whose address identifier is BSSID_2y and an AP 2z whose MAC address identifier is BSSID_2z. An MLD AP set that shares a location with a reporting AP includes the following APs, where the reporting AP refers to an AP that transmits a management frame. The management frame carries information regarding the following plurality of APs, and the management frame is a radio beacon frame, a probe response frame, or similar. The reporting AP includes a transmitting AP and a common AP in the multiple BSSID set. The MLD AP set that shares the same location with the reporting AP includes the following APs: (1) All APs that belong to the same MLD AP as the reporting AP, or all APs in an MLD AP including the reporting AP. (2) All APs in an MLD AP to which a non-transmitted AP is affiliated in the same multiple BSSID set as the reporting AP (or a transmitted AP); or all APs in an MLD AP to which a non-transmitted AP in the multiple BSSID set belongs to the reporting AP (or a transmitted AP). (3) All APs in an MLDAP that satisfy the following two conditions: (1) At least one AP in the MLDAP is in the same multiple BSSID set as an AP in the MLDAP to which (1) The reporting AP is affiliated with MLD; and (2) no AP in the MLD AP works on the same link as the reporting AP. Optionally, in one implementation, an MLD AP includes only one AP. Optionally, the reporting AP can be a common AP (e.g., in FIGURE 4, an AP 3 whose MAC address identifier is BSSID 3 and an AP 5 whose MAC address identifier is BSSID 5) in the MLD AP or the broadcast AP in the multiple BSSID set, and can send unicast service indication information described in this application. For example, an AP 1x in FIGURE 4 is used as a reporting AP; an MLD AP set that shares a location with AP 1x includes the following APs: (1) All APs in the same MLD AP 1 as AP 1x, i.e., AP 1x, AP 2y, and AP3. (2) All APs in an MLD AP 3 including a non-transmitting AP (i.e., AP 1y) in the same multiple BSSID set 1 as AP 1x are respectively AP 1y, AP 2z, and AP 4y. (3) In FIGURE 4, an MLD AP that meets the above conditions (1) and (2) is an MLD AP 2, i.e., it includes an AP 2x and an AP 4x, the AP 2x in MLD AP 2 and the AP 2y in MLD AP 1 are in the same multiple BSSID set 2, and no AP in MLD AP 2 is on the same link as AP 1x. In the 802.11 protocol, a STA typically has two operating modes: a non-power-saving mode and a power-saving mode. When the STA is operating in non-power-saving mode, it is in an active state (also referred to as a wake-up state) regardless of whether there is data to be transmitted. When the STA is operating in power-saving mode, it can be in an active state when data is being transmitted with an AP. When there is no data transmission between the STA and the AP, the STA can be in a doze state to reduce power consumption. The STA can send a frame to the AP to notify it if it is in power-saving mode. If a power-saving bit in a frame control field in a frame MAC address is set to 1, the AP is notified that the STA is in power-saving mode.If the power saving bit in the frame control field in the frame MAC header is set to 0, the AP is notified that the STA is in non-power saving mode. It can be understood that "data transmission" and "transmission data" mentioned in this application generally refer to communication. "Data" generally refers to communication information, but is not limited to data information and may also include signaling information or similar. In a wireless network management (WNM) or target wake-up time (TWT) power-saving mechanism, a STA can communicate with an AP around a wake-up period. The AP sends a traffic indication map (TIM) frame to a plurality of corresponding STAs at the start of each wake-up period. The TIM frame is much shorter than a beacon frame. A TIM element within the TIM frame is used to notify the plurality of STAs if there are corresponding downlink service indications. Because the TIM frame is much shorter than the beacon frame, the STA can achieve a power-saving effect.In a WNM power-saving mechanism, a TIM broadcast interval field in a TIM request frame sent by the STA or a TIM response returned by the AP indicates the wake-up period. Alternatively, in a TWT power-saving mechanism, the wake-up period corresponds to a TWT wake-up interval, where the TWT wake-up interval is calculated based on a decimal TWT wake-up duration field and a TWT wake-up interval exponent field in a TWT element. Specifically, the TWT wake-up interval = decimal TWT wake-up duration * 2 (TWT wake-up interval exponent). Figure 5 is a schematic diagram of a TIM frame structure according to one modality of this application. As shown in Figure 5, a frame carrier in the TIM frame may include at least one of the following: a type field, an unprotected WNM behavior field, a timestamp field, a radio beacon frame check field, a TIM element field, and a link identification information field. The unprotected WNM action field indicates different action values. The timestamp field indicates clock information. The TIM element field indicates whether a non-AP STA or MLD identified by an AID has a downlink service. The link identification information field indicates a specific link.The Radio Beacon Check field indicates a BSS in which a link indicated by the Link ID Information field is located or is used to indicate whether a critical BSS parameter of an AP indicated by Link ID Information field 30 is up to date. Alternatively, the Radio Beacon Check field indicates whether a critical parameter of a link indicated by the Link ID Information field is up to date. For example, if a critical BSS parameter of a BSS in which the link indicated by the link identification information field is located is updated, or a critical parameter of the link indicated by the link identification information field is updated, a value in the radio beacon check field is incremented by 1. The BSS parameter ML / 1 / ZUZÓ / UÓUO4O can also be understood as a linking parameter. Correspondingly, the critical BSS parameter can be understood as a critical linking parameter. For example, each time a non-AP MLD stores a beacon check value for each link, it records the value of the most recently received beacon check field. If a recently received beacon check value for a link differs from the most recently received beacon check value for that link, the non-AP MLD receives a beacon frame on that link, sent by an AP MLD. Alternatively, the non-AP MLD can send a probe request frame on any link, where the probe request frame is used to request a critical BSS parameter from one or more APs. The probe request frame includes a link identifier for one or more APs. Optionally, the probe request frame also includes an MLD identifier for an MLD including the AP, such as an MLD MAC address or an MLD sequence number of the AP MLD.After receiving the probe request frame, the MLD AP returns an acknowledgment frame and then sends a probe response frame to the non-AP MLD. The probe response frame includes a last critical BSS parameter from one or more APs requested by the non-AP MLD. After receiving the frame, the non-AP MLD responds with the acknowledgment frame. In the probe response frame, a value in the radio beacon check field corresponding to one or more APs changes. This radio beacon frame can be understood to carry the last critical BSS parameter of the link. It can be understood that, because the TIM table includes the Link Identification Information field, when using the TIM table in a BSS, even if the non-AP MLD includes multiple STAs, only one AID is required. In combination with the Link Identification Information and the AID, a station operating on the link indicated by the Link Identification Information field and providing downlink service can be identified. Furthermore, it can be understood that the radio beacon check field and the link identifier information field, which are included in the TIM table, can alternatively be placed in another management table. The plurality of fields (referring here to the radio beacon check field and the link identifier information field) can be used separately to notify if a critical BSS parameter in a BSS containing the link indicated by the link identifier information field is changed or updated. The above method can also be used to determine if a critical BSS parameter in multiple BSSs containing multiple links is changed or updated. For example, the management table includes a number of links, n radio beacon check fields, and yn link identifier information fields, where n is indicated by a link quantity field.For another example, the management box includes a link identifier bitmap and n radio beacon check fields, and optionally includes a link identifier bitmap length field, where n is the number of first values ​​(for example, 1) in the link identifier bitmap. Values ​​in one or more radio beacon check fields are initialized to 0. In one implementation, FIGURE 6 is a schematic diagram of a management box frame structure according to one modality of this application. As shown in FIGURE 6, a management box frame carrier includes a type field, an unprotected WNM behavior field, a link quantity field, a radio beacon check field, a TIM element field, and a link identification information field.When multiple links are indicated by the number of links field, for each link there is a radio beacon check field, a TIM element field, and a link identification information field. Optionally, the management chart carrier may also include one or more timestamp fields. The management chart shown in Figure 6 may indicate whether a plurality of stations operating on a link indicated by each link identification information field has a downlink service. In conclusion, as shown in Figure 4, some APs (e.g., APs not broadcasting on the same multiple BSSID set) cannot send a management frame. Therefore, these APs cannot notify, by sending a management frame such as a radio beacon frame or probe response frame, an associated non-AP STA / MLD regarding whether critical BSS parameters managed by these APs are up to date. Consequently, the non-AP STA / MLD associated with these APs and listening on operational links from these APs is unaware that the critical BSS parameters of these APs are up to date. As a result, after the critical BSS parameters are updated by these update APs, the non-AP STA / MLD associated with these APs cannot operate normally or communicate with these APs. Therefore, this application provides a method for managing critical BSS parameters applicable to multiple links. One MLD AP can assist another MLD AP in notifying it whether critical BSS parameters from multiple APs in the other MLD AP are up to date, thus resolving the issue where some APs are unable to report that their critical BSS parameters are updated. A STA can be assisted in receiving the latest critical BSS parameter, so that after multiple APs in the other MLD AP update the critical BSS parameter, a non-AP MLD associated with the other MLD AP can still operate normally. The following describes the solutions in detail. ML / 1 / ¿UZÓ / UÓUO4O techniques provided in this application with reference to additional accompanying drawings. Modality 1 Mode 1 of this application describes a method for managing critical BSS parameters applicable to multiple links, specifically relating to a critical BSS parameter update indication applicable to multiple links. Not only can critical BSS parameter update count values ​​be specified for a plurality of APs on a first MLD AP (this value is located in a reduced neighbor report (RNR) element), but critical BSS parameter update count values ​​can also be specified for a plurality of APs on a second MLD AP. Therefore, a non-AP MLD associated with the second MLD AP can listen on a link where a non-transmitting AP on the second MLD AP is operating, and it can also function normally. In other words, the non-AP MLD may have more listening channel options. Each reporting AP in the first MLD AP needs to send, to any non-AP MLD associated with the first MLD AP or a surrounding station (the surrounding station includes a station managed by the reporting AP and a station not associated with the first MLD AP), the critical BSS parameter update count values ​​corresponding to the plurality of APs in the first MLD AP, and send the critical BSS parameter update count values ​​corresponding to the plurality of APs in the second MLD AP. For ease of description, in Mode 1 of this request, a reporting AP is used in the first MLD AP. Figure 7 is a schematic flowchart of a critical BSS parameter management method applicable to multiple links according to one modality of this application. An MLD AP includes one or more APs, and a first AP is any reporting AP in the MLD AP. Optionally, the reporting AP is not a non-transmitting AP in a multiple BSSID set. A first STA can be a single-link STA or any STA in a non-AP MLD. For ease of description, the following uses the first STA in the non-AP MLD as an example. The first AP and the first STA operate on the same link. As shown in Figure 7, an association method applicable to a multi-link device includes, but is not limited to, the following steps. S101: The first AP in the first MLD AP generates a first frame, where the first frame indicates critical BSS parameter update information corresponding to a plurality of APs in the first MLD AP and critical BSS parameter update information corresponding to a plurality of APs in a second MLD AP, and the second MLD AP is an MLD AP to which a non-transmitted AP belongs in a multiple BSSID set including the first AP. A piece of critical BSS parameter update information corresponding to an AP is used to determine if a parameter Critical BSS in an AP-managed BSS is up to date. The first AP can be any reporting AP in the first MLD AP, and the reporting AP can be an AP that sends a management frame (for example, a radio beacon frame or a probe response frame). The critical BSS parameter update information includes a critical BSS parameter update count value. The first table can be the management table, for example, the radio beacon table, the probe response table, or another management table. The first table can indicate critical BSS parameter update count values ​​corresponding to the plurality of APs (the plurality of APs here being all APs in the first MLD AP, or all APs or some APs in the first MLD AP except the first AP) in the first MLD AP and critical BSS parameter update count values ​​corresponding to the plurality of APs (the plurality of APs here being all APs or some APs in the second MLD AP) in the second MLD AP. The second MLD AP is an MLD AP to which a non-transmitting AP belongs in the multiple BSSID sets in which the first AP is located. Optionally, the critical BSS parameter update count value is incremented by 1 when one or more critical BSS parameter values ​​change.A critical BSS parameter update count value for an AP can be used to determine whether a critical BSS parameter in a BSS managed by the AP is up to date. The critical BSS parameter update count value can be a natural number, and it is initialized to 0. When a critical BSS parameter in a BSS managed by the AP changes, the corresponding critical BSS parameter update count value for the AP is incremented by 1. Because there are critical BSS parameter update count values ​​for multiple APs, each critical BSS parameter update count value is one-to-one with an AP identifier. The AP identifier can be an AP MAC address, an AP link identifier, or a combination of an AP operational class, a channel number, and a BSSID.The critical BSS parameter update count value can be carried in a reduced neighbor report element (RNR element) of the first box. The following describes the reduced neighbor report element. Optionally, in addition to a critical BSS parameter update count value field, the RNR element in this application mode can also include a link identifier field and an AP MLD identifier field (for example, an MLD ID field). The link identifier field indicates an AP or station on which a specific link operates. The link identifier field can be understood as a link identifier information field or a bitmap field. The link identifier ML / 1 / ¿UZÓ / UÓUO4O (used to indicate a bitmap in link identifiers corresponding to a plurality of APs) is not limited in this modality of this request. The critical BSS parameter update count value field indicates the critical BSS parameter update count value. It may be understood that the critical BSS parameter update count value field can be referred to as a critical BSS parameter update field. This is not limited in this modality of this request. The MLD AP identifier field can be used to identify a specific MLD AP. It may be understood that the MLD AP identifier field can be an MLD ID field, an MLD index field, an MLD sequence number field, or similar, and the name of the identifier field is not limited. Because the RNR element includes the link identifier field and the MLD AP identifier field (just like the MLD ID field), when using the RNR element, even if each MLD AP includes multiple APs, each MLD AP has an identifier. In combination with a link's identifier information and the MLD AP's identifier information, you can determine which AP is working on a link indicated by the link identifier field and whose critical BSS parameter is being updated. It can be understood that, in order to associate with the AP, the station first needs to perform a scan to report the AP's existence. There are two types of scans: active scans and passive scans. Passive scanning means that a station receives a management frame sent by an access point (AP) on a channel, such as a beacon frame, association response frame, authentication frame, or probe response frame. For example, the station switches between different channels to search for the beacon frame sent by the AP. Once the station obtains admission control information from the AP using the beacon frame, it can also obtain additional information from the AP by exchanging a probe request frame and a probe response frame. Active scanning means that a station actively sends a Probe Request frame when the station does not detect a radio beacon frame, where if a specific condition is met, an AP that receives the probe request frame can initiate random channel access to respond with a probe response frame. In the scanning process, to assist the station in rapid scanning, the AP includes a reduced neighbor reporting element in a management box, such as a beacon box or probe response box, to prevent the station from continuously performing channel scans. This reduces the scanning time of the ML / 1 / ZUZÓ / UÓUO4O station. The AP carries the reduced neighbor reporting element in a management box, for example, a radio beacon box or a probe response box. During a scan, a station receives a management box sent by the AP, obtains information about surrounding APs based on the reduced neighbor reporting element in the management box, and then chooses to associate with an appropriate AP. Specifically, the reduced neighbor report element typically carries one or more Neighbor AP information fields, which are used to describe one or more neighboring APs and information regarding the BSS to which those APs belong. Figure 8A is a schematic diagram of a box structure for an RNR element according to one modality of this request. As shown in Figure 8A, the reduced neighbor report element may include some or all of the following fields: a Target Beacon Transmission Time (TBTT) information header field, an operating class field, a channel number field, and one or more TBTT information set fields.The TBTT information set field includes one or more TBTT information fields, and a TBTT identifier field corresponds to a neighboring AP. The TBTT information header field leads to at least one of the following information: a field of TBTT information field type, indicating a TBTT information type, wherein the field is used in conjunction with a TBTT information length field to indicate a format of the TBTT information field; a filtered neighbor AP field, indicating whether the SSIDs of all BSSs carried in the neighbor AP information field match an SSID in a probe request box; a 1-bit reserved (Reserved field); A TBTT information count field indicates the number of TBTT information fields included in a TBTT information set; and a TBTT information length field indicates the length of each TBTT information field. Table 1 below shows specific information formats carried at different lengths. Table 1 ML / 1 / ¿UZÓ / UÓUO4O TBTT Information Length (bytes) Content Carried in a TBTT Information Field 1 TBTT offset field of a neighboring AP 2 TBTT offset field and BSS parameter field of a neighboring AP 5 TBTT offset field and short SSID field of a neighboring AP 6 TBTT offset field, short SSID field, and BSS parameter field of a neighboring AP 7 TBTT offset field and BSSID field of a neighboring AP 8 TBTT offset field, BSSID field, and BSS parameter field of a neighboring AP 11 TBTT offset field, BSSID field, and short SSID field of a neighboring AP 12 TBTT offset field, BSSID field, short SSID field, and BSS parameter field of a neighboring AP 0, 9-10 Reserved 13-255 Reserved, but information regarding the first 12 bytes is the same as fields carried when TBTT information length is 12. The following provides a specific format for the TBTT Information field present when the TBTT information length is 12 bytes. Neighbor AP TBTT offset field: indicates an offset of a Radiobeacon transmission time between the neighbor AP and the reporting AP: a BSSID (BSS identifier) ​​field, indicating a BSS identifier corresponding to the neighbor AP; a short SSID (short service set identifier) ​​field, indicating a service set identifier to which the neighboring AP belongs; and a BSS parameter field, indicating a related parameter of a neighboring AP. Optionally, in addition to the neighboring AP TBTT compensation field, the field BSSID, the short SSID field, and the BSS parameter field, a TBTT identifier field in the RNR element in this mode of this request includes: at least one of a critical BSS parameter update count value field, a link identifier (Link ID) field, and a multi-link device identifier (MLD ID) field. Figure 8B is a schematic diagram of a box structure for a TBTT identifier field in an RNR element, according to one modality of this application. As shown in Figure 8B, a TBTT identifier field of the RNR element includes at least one of the following fields: a Neighbor AP TBTT Offset field, a BSSID field, a Short SSID field, a BSS Parameter field, a Critical BSS Parameter Update Count Value field, a Link Identifier (Link ID) field, and a Multi-Link Device Identifier (MLD ID) field. It can be understood that Figure 8B is merely an example, and a sequence of the Critical BSS Parameter Update Count Value field, the Link ID field, and the MLD ID field that are included in the TBTT information field, and if another field exists between the Critical BSS Parameter Update Count Value field, the Link ID field, and the MLD ID field, it is not limited. It can be understood that the three fields—the critical BSS parameter update count value field, the link identifier field, and the MLD identifier field—are independent, and all of them can be carried in the RNR element, or they may not all be carried in the RNR element. In other words, the RNR element can carry some of the three fields. The Critical BSS Parameter Update Count Value field indicates the critical BSS parameter update count value. The Link Identifier field indicates a specific link. The MLD ID field indicates a specific MLD AP. It can be understood that a TBTT Identifier field corresponds to an AP, an AP manages a BSS, and each TBTT Identifier field carries an MLD ID field and a Link Identifier field. Therefore, when using a first frame, even if an MLD AP includes multiple APs within a BSS, different APs within the MLD AP can be distinguished based on a link indicated by the Link Identifier field and an MLD indicated by the MLD ID field. In other words, the Link Identifier field, in combination with the MLD ID field, can uniquely identify an AP. The BSS parameter field indicates a related parameter of the neighboring AP. Specifically, a related parameter of the neighboring AP includes the following information: a recommended OCT field (recommended in-channel signaling mechanism), indicating that the neighboring AP expects to exchange a management-type MPDU with the reporting AP using the OCT mechanism; ML / 1 / ¿UZÓ / UÓUO4O the same SSID field (same service set identifier), indicating whether the neighbor AP and the reporting AP have the same SSID; a multiple BSSID (multiple Basic Service Set Identifier) ​​field, indicating whether the neighboring AP is part of a multiple BSSID set; a transmitted BSSID field (transmitted Basic Service Set Identifier) ​​indicating, if the neighbor AP is a transmitted BSSID or a non-transmitted BSSID if the neighbor AP is part of the multiple BSSID set; an ESS element field with co-located 2.4 / 5 GHz AP (extended services set element with co-located 2.4 / 5 GHz AP), indicating whether the neighbor AP is a member of an extended services set with co-located 2.4 / 5 GHz AP (i.e., whether the neighbor AP is a 6 GHz only AP); an unsolicited probe response active field, indicating whether the neighboring AP allows an active probe response; and a co-located AP field, indicating whether the neighboring AP and reporting AP 15 are co-located. It should be noted that, in this form of the request, an AP described in a neighbor report element or a reduced neighbor report element is a reported access point (AP), and a neighbor AP mentioned later may be understood as the reported AP. An AP that sends the neighbor report element or the reduced neighbor report element is a reporting access point (AP). The RNR element was described in the previous content. The following describes a second 25 MLD AP. Optionally, the second MLD AP is an MLD AP to which a non-broadcast AP belongs in the multiple BSSID set including the first AP. For example, as shown in FIGURE 4, an AP 1x is assumed to be a first AP. The first AP sends a management frame, for example, a radio beacon frame or a probe response frame, and carries an RNR element. The RNR element carries critical BSS parameter update count values ​​from a plurality of APs in a first MLD AP, and critical BSS parameter update count values ​​from a plurality of APs in a second MLD AP. An MLD AP 1 is the first MLD AP, and an MLD AP 3 is the second MLD AP. Therefore, the first frame includes critical BSS parameter update count values ​​corresponding to the plurality of APs in MLD AP 1; for example, it includes a critical BSS parameter update count value corresponding to an AP 2y and a critical parameter update count value from an AP 3y. ML / 1 / ZUZÓ / UÓUO4O critical BSS parameter update corresponding to AP 3. The first table also includes critical BSS parameter update count values ​​corresponding to the plurality of APs in the MLD AP 3, for example, it includes a critical BSS parameter update count value corresponding to AP 1y, a critical BSS parameter update count value corresponding to AP 2z, and a critical BSS parameter update count value corresponding to AP4y. Optionally, the management table sent by the first AP also includes a critical BSS parameter update count value corresponding to AP 1x. The critical BSS parameter update count value of AP 1x is located in the common MLD information of a multi-link (ML) element 10 or in an EHT operation element.A common information field of MLD or the EHT operation element in the ML element also carries a link identifier of the first AP, i.e., AP 1x. For another example, as shown in FIGURE 4, it is assumed that AP 2x is the first AP, MLD AP 2 is the first MLD AP, and both MLD AP 1 and MLD AP 3 are the second MLD AP. Therefore, the first table includes critical BSS parameter update count values ​​corresponding to a plurality of APs in MLD AP 2; for example, it includes a critical BSS parameter update count value corresponding to AP 4x. The first table also includes critical BSS parameter update count values ​​corresponding to the plurality of APs in MLD AP 1; for example, it includes the critical BSS parameter update count value corresponding to AP 1x, the critical BSS parameter update count value corresponding to AP 2y, and the critical BSS parameter update count value corresponding to AP 3.The first table also includes critical BSS parameter update count values ​​corresponding to a plurality of APs in MLD AP 3; for example, it includes the critical BSS parameter update count value of 25 for AP 1y, the critical BSS parameter update count value for AP 2z, and the critical BSS parameter update count value for AP 4y. Optionally, the management table sent by the first AP also includes the critical BSS parameter update count value for AP 2x. The critical BSS parameter update count value for AP 2x is located in the common MLD information of the common ML element or the EHT operation element. The common information field of the MLD or the EHT operation element in the ML element also carries the link identifier of the first AP, i.e., AP 2x. For another example, as shown in FIGURE 4, it is assumed that AP 4x is the first AP, MLD AP 2 is the first MLD AP, and both MLD AP 3 and MLD AP 4 are the second MLD AP. Therefore, the first table includes critical BSS parameter update count values ​​corresponding to a plurality of APs in MLD AP 2; for example, it includes a critical BSS parameter update count value corresponding to AP 2x. The first table also includes critical BSS parameter update count values ​​corresponding to the plurality of APs in MLD AP 3; for example, it includes the critical BSS parameter update count value corresponding to AP 1y, the critical BSS parameter update count value corresponding to AP 2z, and the critical BSS parameter update count value corresponding to AP 4y.The first table also includes critical BSS parameter update count values ​​corresponding to a plurality of APs in MLD AP 4; for example, it includes the critical BSS parameter update count value corresponding to AP 4z and the critical BSS parameter update count value corresponding to AP 5. Optionally, the management table sent by the first AP also includes the critical BSS parameter update count value corresponding to AP 4x. The critical BSS parameter update count value for AP 4x is located in the common MLD information of the common ML element or the EHT operation element. The common MLD information field or the EHT operation element in the ML element also carries the link identifier of the first AP, i.e., AP 4x. For another example, as shown in FIGURE 4, it is assumed that AP 3 is the first AP, MLD AP 1 is the first MLD AP, and there is no second MLD AP. Therefore, the first management box includes the critical BSS parameter update count values ​​corresponding to the plurality of APs in MLD AP 1; for example, it includes the critical BSS parameter update count value 20 corresponding to AP 1x and the critical BSS parameter update count value corresponding to AP 2y. Optionally, the management box sent by the first AP also includes the critical BSS parameter update count value corresponding to AP 3. The BSS parameter update count value of AP 3 is located in the common MLD information of the common ML element or the EHT operation element. The common information field of the MLD or the EHT operation element in the ML element also carries the link identifier of the first AP, which is AP3. S102: The first AP in the first MLD AP sends the first frame on a link on which the first AP works. Specifically, the first AP in the first MLD AP needs to send, on the link where the first MLD AP operates, the first frame to a non-AP MLD associated with the first MLD AP or to a station around the first AP. A station around the first AP includes a station managed by the first AP and a non-associated station. The following uses the AP-managed station as an example to describe the critical BSS parameter management method applicable to multiple links in this application mode. It can be understood that the first frame can be sent in either a single-broadcast or multi-broadcast manner. ML t / ¿UZÓ / UÓUO4O Furthermore, the non-AP MLD associated with the first AP MLD in this application modality can be understood in two ways: (1) All non-AP MLDs that establish a multi-link association with the first AP MLD. The non-AP MLD can establish associations with some APs in the first AP MLD, or it can establish associations with all APs. (2) A non-AP MLD associated with the first AP exists in the first AP MLD. The non-AP MLD can establish associations with some APs in the first AP MLD, or it can establish associations with all APs, but some or all APs need to include the first AP. The first AP is a reporting AP. S103: A first STA of the non-AP MLD receives the first frame on a link on which the first STA works. The first STA can be a station managed by the first AP or a station located near the first AP, and it can learn if a critical BSS parameter of a BSS to which the first STA belongs is up to date. The first STA and the first AP operate on the same link / frequency band / channel. S104: The first STA of the non-AP MLD determines, based on the first table, whether critical BSS parameters of a plurality of BSS managed by a plurality of APs in an AP MLD associated with the non-AP MLD are up to date. Specifically, after receiving the first frame, the first STA of the non-AP MLD can analyze the first frame to obtain critical BSS parameter update count values ​​corresponding to the plurality of APs in the first AP MLD and the critical BSS parameter update count values ​​corresponding to the plurality of APs in the second AP MLD. The non-AP MLD analyzes, starting from the first frame, M critical BSS parameter update count values ​​corresponding to M APs (the M APs have an association relationship with the non-AP MLD) in the AP MLD associated with the non-AP MLD.For each AP in the M APs, the non-AP MLD compares a value ratio between a critical BSS parameter update count value received at this time and a critical BSS parameter update count value received last time; or it compares whether the critical BSS parameter update count value received at this time is the same as the critical BSS parameter update count value received last time. If the critical BSS parameter update count value received at this time is different from the critical BSS parameter update count value received last time, the non-AP MLD determines that the critical BSS parameter in the BSS managed by the AP is up to date.Optionally, when the critical BSS parameter update count received at this time differs from the critical BSS parameter update count received last time, the non-AP MLD can listen to the beacon box on the link where the AP is operating. The beacon box carries the latest critical BSS parameter from the AP. Alternatively, a STA. MLD non-AP ML / 1 / ZUZÓ / UÓUO4O can obtain a final critical BSS parameter from the AP by sending a probe request box with reference to the above description. If the critical BSS parameter update count value received at this time is the same as the critical BSS parameter update count value received last time, this indicates that the AP-managed BSS is not updating the critical BSS parameter, and the non-AP MLD cannot perform processing. Optionally, each time the non-AP MLD records a critical BSS parameter update count value corresponding to each link received last time. For example, as shown in FIGURE 4, the first AP is assumed to be AP 1x, MLD AP 1 is the first MLD AP, and MLD AP 3 is the second MLD AP. It is assumed that non-AP MLD 1 is associated with AP 1y, AP 2z, and AP 4y of MLD AP 3, M equals 3, and the APs associated with non-AP MLD 1 are AP 1y, AP 2z, and AP 4y. The first table includes the critical BSS parameter update count value corresponding to AP 1x of MLD AP 1, the critical BSS parameter update count value corresponding to AP 2y, and the critical BSS parameter update count value corresponding to AP 3. The first table also includes the critical BSS parameter update count value corresponding to AP 1y, the critical BSS parameter update count value corresponding to AP 2z, and the critical BSS parameter update count value corresponding to AP 4y of MLD AP 3. In other words, N equals 6.Starting with the first frame, non-AP MLD 1 analyzes three critical BSS parameter update count values ​​corresponding to AP 1y, AP 2z, and AP 4y in AP MLD 3, which is associated with non-AP MLD 1. For AP 1y, non-AP MLD 2 compares whether the critical BSS parameter update count value for AP 1y received at this time is the same as the critical BSS parameter update count value for AP 1y received last time. If the critical BSS parameter update count value for AP 1y received at this time and the critical BSS parameter update count value for AP 1y received last time are different, this indicates that the critical BSS parameters of the BSS managed by AP 1y are up to date. Non-AP MLD 1 can listen, on link 1 where AP 1y is located, for a radio beacon frame carrying a last critical BSS parameter.For AP 2z, non-AP MLD 1 compares whether the critical BSS parameter update count value for AP 2z received at this time is the same as the critical BSS parameter update count value for AP 2z received last time. If the critical BSS parameter update count value for AP 2z received at this time and the critical BSS parameter update count value for AP 2z received last time are different, this indicates that critical BSS parameters of the BSS managed by AP 2z are up to date. MLD no38. AP 1 can listen, on link 2 where AP 2z is located, for the radio beacon frame carrying the last critical BSS parameter. For AP 4y, the non-AP 1 MLD compares whether the critical BSS parameter update count value received by AP 4y at this time is the same as the critical BSS parameter update count value received by AP 4y at the last time. If the critical BSS parameter update count value received by AP 4y at this time and the critical BSS parameter update count value received by AP 4y at the last time are different, this indicates that the critical BSS parameters of the BSS managed by AP 4y are up to date. The non-AP 1 MLD can listen, on link 4 where AP 4y is located, for the radio beacon frame carrying the last critical BSS parameter. For another example, assume that non-AP MLD 2 is associated with AP 1y and AP 4y of MLD AP 3. In this case, M equals 2, and the APs that have an association relationship with non-AP MLD 2 are AP 1y and AP 4y. Therefore, for AP 1y, non-AP MLD 2 compares whether the critical BSS parameter update count value corresponding to AP 1y received at this time is the same as the critical BSS parameter update count value corresponding to AP 1y received last time. If the critical BSS parameter update count value corresponding to AP 1y received at this time and the critical BSS parameter update count value corresponding to AP 1y received last time are different, this indicates that the critical BSS parameters of the BSS managed by AP 1y are up to date.The non-AP MLD 2 can listen, on link 1 where AP 1y is located, for a radio beacon frame carrying a critical BSS parameter. For AP 4y, the non-AP MLD 2 compares whether the critical BSS parameter update count value for AP 4y received at this time is the same as the critical BSS parameter update count value for AP 4y received last time. If the critical BSS parameter update count value for AP 4y received at this time and the critical BSS parameter update count value for AP 4y received last time are different, this indicates that the critical BSS parameters of the BSS managed by AP 4y are up to date. The non-AP MLD 2 can listen, on link 4 where AP 4y is located, for the radio beacon frame carrying the critical BSS parameter. It can be understood that when the first STA is a single-link STA, when the first STA switches from one link to another link to work, the first STA can obtain a critical BSS parameter update count value using the method in this mode of this request. It can be learned that in this modality of this request, using the first table 35 sent by the first AP, not only are critical BSS parameter update count values ​​corresponding to the plurality of APs in the first MLD AP indicated, but also ML / 1 / ZUZÓ / UÓUO4O critical BSS parameter update count values ​​corresponding to the plurality of APs on the second MLD AP. This implements that one AP assists a plurality of APs on another MLD AP in indicating corresponding critical BSS parameter update count values, so that a STA can compare a currently received critical BSS parameter update count value with a critical BSS parameter update count value received last time, and check if a critical BSS parameter is up to date. Therefore, the STA can be assisted in receiving the latest critical BSS parameter, and a non-AP MLD associated with the second MLD AP can listen on a link where a non-transmitting AP on the second MLD AP is operating, and can also operate normally. In other words, for the non-AP MLD, there can be more channels to be listened to for selection. In 802.11. It is possible that all or some APs in an MLD AP may be non-transmitting APs. Therefore, the solution provided in this modality of this request can resolve the issue of some non-transmitting APs being unable to send a management box to notify that a critical BSS parameter has been updated. This can thus improve the integrity and diversity of a critical BSS parameter update indication. In an optional mode, a method for each non-AP MLD to obtain initial values ​​of the critical BSS parameter update count values ​​of the AP plurality in the AP MLD associated with the non-AP MLD is as follows. 1. In an association phase, an association response frame sent by an AP in the MLDAP carries current critical BSS parameter update count values ​​from the plurality of APs in the MLDAP. 2. When a STA on the non-AP MLD requests to switch to another link, the channel switch signaling implicitly indicates a request to the MLDAP for a critical BSS parameter update count value from an AP operating on the link. A response frame with which the associated MLD AP responds on the link corresponding to the STA needs to carry the latest critical BSS parameter update count value from the AP operating on the other link at that time. The channel change signaling includes a link identifier corresponding to the AP to which the STA needs to switch. For example, as shown in Figure 4, assuming that STA 1 on a non-AP MLD 1 requests a switch from link 1 to link 2, the channel change signaling includes a link identifier for link 2. Assuming that non-AP MLD 1 is associated with the MLDAP, the channel change signaling implicitly indicates a request to AP 1 for a critical BSS parameter update count value from AP 2 operating on link 2. The response box returned by AP 1 on link 1 to STA 1 needs to carry the latest critical BSS parameter update count value from AP 2 operating on link 2 at that time. When the critical BSS parameter update count value received and sent by the AP is different from the critical BSS parameter update count value received last time, in addition to acquiring a last critical BSS parameter by receiving a radio beacon frame and sending a probe request, a locally stored critical BSS parameter update count value of 5 needs to be updated to a critical BSS parameter update count value received at this time. In another optional mode, an MLD AP has a common SSID, and optionally, each AP has a separate SSID. During an MLD discovery phase of neighbor or APs, the non-AP MLD can discover an optimal MLD AP for association as soon as possible, including the discovery of a preferred SSID. For a reported AP (i.e., a neighbor AP) in the MLD AP, a short SSID field for each reported AP (i.e., a neighbor AP) in the RNR element in this mode of this request carries: a short SSID calculated based on the SSID of the MLD AP in which the reported AP (i.e., the neighbor AP) is located. For details regarding how to calculate the short SSID, refer to the 802.11-2016 protocol. It can be understood that this modality of this request can be implemented separately, or it can be implemented with reference to the method shown in FIGURE 7. This is not limited in this modality of this request. It can be learned that compared to a case in which the short SSID of the reported AP is directly carried in the RNR element, in the non-AP MLD in this modality of this request, an optimal MLD AP can be quickly selected for association in a discovery phase using a short SSID of the MLD AP to which the reported AP belongs, thus improving the efficiency of the association. In another optional mode, the first box can also be used to specify critical BSS parameters specific to the AP plurality in the first MLD AP and 25 critical BSS parameters specific to the AP plurality in the second MLD AP. A specific critical BSS parameter is a BSS parameter related to a channel change. Specific critical BSS parameters can include one or more of the following: an inclusion of a channel change advertisement element, an inclusion of an extended channel change advertisement element, an inclusion of a wideband channel change element, and an inclusion of a channel change wrapper element. Mode 2 Mode 2 of this application provides a method for updating a critical BSS parameter, applied to a multi-link device, to describe how to update a critical BSS parameter. It can be understood that, in actual application, Mode 2 of this application may be implemented separately, or it may be implemented with reference to Mode 1. This is not limited in this application. ML / 1 / ZUZÓ / UÓUO4O Figure 9 is a schematic flowchart of a method for updating a critical BSS parameter according to one modality of this request. An MLD AP includes one or more APs; a second AP is any AP within the MLD AP, and the second AP may or may not be a reporting AP. The second STA may be a single-link STA, or it may be any STA within a non-AP MLD. For ease of description, the following uses a second STA within the non-AP MLD as an example. The second AP and the second STA operate on the same link. As shown in Figure 9, the method for updating a critical BSS parameter includes, but is not limited to, the following steps. S201: A second AP in a first MLD AP generates a second frame, wherein the second frame indicates critical BSS parameters specific to a plurality of APs in the first MLD AP and / or critical BSS parameters specific to a plurality of APs in a second MLD AP, and the second MLD AP is an MLD AP to which a non-transmitted AP belongs in a multiple BSSID set including the second AP. The second panel can be a management panel, such as a radio beacon panel, or it can be another panel. The second panel and the first panel in Mode 1 can be one panel, or they can be different panels. This is not limited in this mode of this application. The second panel can indicate critical BSS parameters specific to the plurality of APs in the first MLD AP (the plurality of APs here is all the APs in the first MLD AP, or all the APs or some APs in the first MLD AP except the first AP), and / or critical BSS parameters specific to the plurality of APs in the second MLD AP (the plurality of APs here is all or some APs in the second MLD AP). The specific critical BSS parameter may include one or more of the following: an inclusion of a Channel Switch Announcement element, an inclusion of an Extended Channel Switch Announcement element, an inclusion of a Wide Bandwidth Channel Switch element, and an inclusion of a Channel Switch Wrapper element. If all or some of the above four elements are changed / updated, but a station is not notified of the change / update in time (possibly because the station does not receive the updated elements), the station cannot find a corresponding AP in the MLD AP. As a result, a terminal cannot communicate with a corresponding AP in the MLD AP.Therefore, the specific critical BSS parameter needs to be carried over. Optionally, the specific critical BSS parameter may also include one or more of the following: an inclusion of a quiet element and an inclusion of a quiet channel element. Optionally, the A specific critical BSS parameter may also include one or more of the following: an EDCA parameter element modification, a DSSS parameter set modification, a CF parameter set element modification, an HT operation element modification, an operating mode notification element inclusion, a VHT operation element modification, an HE operation element modification, a transmission TWT element insertion, a BSS color change announcement element inclusion, an EDCA MU parameter set element modification, and a spatial reuse parameter set element modification. One or more of the above specific critical BSS parameters may also be listed as a critical parameter of a link. Optionally, the specific critical BSS parameter can be carried in the AP information of a multi-link (ML) element in the second frame. The specific critical BSS parameter for each AP is carried in the respective AP information of the ML element. The following describes a multi-linked element. Figure 10A is a schematic diagram of a box structure for an ML element according to one modality of this application. As shown in Figure 10A, the ML element includes a common control field, common MLD information, and one or more optional sub-elements. Optionally, the common MLD information includes an MLD MAC address field, and optionally includes an authentication algorithm field and a link identifier (link ID) field. The MLD MAC address field indicates an address of the MLD, and this address is used to identify the MLD. Optionally, the MLD address is a MAC address of the MLD. In other words, the MAC address is used to identify an MLDAP management entity. The MAC address of the MLD AP can be the same as the MAC address of any n APs included in the MLD AP, or it can be different from all the MAC addresses of the n APs.For example, the MAC address of the MLD AP is a public MAC address, and it can identify the MLD AP. Optionally, the common control field may include an MLD MAC address existence field (also referred to as an MLD MAC address presence field or MLD MAC address presence identifier), used to indicate whether an MLD MAC address field exists in the common MLD information. Optionally, the common control field may also include an authentication algorithm presence field, to indicate whether an authentication algorithm field exists in the common MLD information. Optionally, the presence field may include a bit. A first value indicates that a corresponding field is present, and a second value indicates that the corresponding field is not present. For example, the first value is 1, and the second value is 0. Optionally, the common control field may also include a link ID presence field, used to indicate whether a ML / 1 / ¿UZÓ / UÓUO4O link field ID in common information MLD. Optionally, an ML element also includes one or more subelements, and a subelement describes information about an AP in an MLD AP. The content of each subelement includes an AP link identifier. Optionally, each subelement also includes AP-related fields, such as an SSID field, a timestamp field, a beacon interval field, and an AP element. The AP element is, for example, a BSS load element, an EHT capacity element, or an EHT operation element. Figure 10B is a schematic diagram of the first part of a box structure for an ML element according to one modality of this application. As shown in Figure 10B, the first part of the ML element does not include the AP information sub-element in the MLD AP. The first part of the ML element includes a common control field and common MLD information. The common control field includes one or more, or all, of an MLD MAC address presence field, a link ID presence field, an MLD sequence number presence field, and a sub-element presence field. Optionally, an authentication algorithm presence field is included. The MLD MAC address presence field indicates whether the common MLD information includes an MLD MAC address field. The link ID presence field is used to indicate whether the public MLD information includes a link ID field.The MLD Sequence Number Presence field indicates whether the common MLD information includes an MLD Sequence Number field. The above fields can be indicated separately using a single bit. For example, 1 indicates that the field is present, and 0 indicates that the field is not present. Alternatively, two values ​​for a field can be used separately for indication, where the first value indicates that the field is present, and the second value indicates that the field is not present. Optionally, the first part (here referring to the common control field and common MLD information shown in FIGURE 10A) of the ML element shown in FIGURE 10A can alternatively be the first part (here referring to the common control field and common MLD information shown in FIGURE 10B) of the ML element shown in FIGURE 10B. The MLD AP can be used to provide additional detailed information for a non-AP MLD station, for example, placed in a probe response box or an association response box.Optionally, the common control field includes a common MLD information presence field, used to indicate whether common MLD information is present, or whether a field other than the MLD MAC address or MLD sequence number is present in the common MLD information, to further reduce duplicate information (it is assumed that the non-AP MLD has learned an authentication algorithm and a link identifier). In a radio beacon box, to avoid excessive content and to prevent repetition of information for each AP in an RNR element, the radio beacon box needs to carry only the common MLD information in the MLD element or some fields in the common MLD information. In this case, the common control field includes a subelement presence field, which means that a subelement used to indicate specific information from a plurality of APs in the ML element is not present, as shown in FIGURE 10B. If the reporting AP belongs to a multiple BSSID set, the reporting AP also needs to send multiple BSSID elements, including a nontransmitted profile, to indicate information about one or more nontransmitted APs. If a nontransmitted AP is from an MLD AP, the first part of the ML element shown in Figure 10B or a complete part of the ML element shown in Figure 10A can be added to the information referencing the nontransmitted AP. The following describes several elements included in the specific critical BSS parameter. Figure 11A is a schematic diagram of a box structure for including a Channel Switch Advertisement element according to a modality of this application. As shown in Figure 11A, including a Channel Switch Advertisement element includes a Channel Switch Mode field, a New Channel Number field, and a Channel Switch Count field. The Channel Switch Mode field indicates a transmission restriction prior to the channel switch (the Channel Switch Mode field indicates any transmission restrictions until a channel switch occurs). The New Channel Number field indicates the channel number to which a station is switching (the New Channel Number field is set to the channel number to which the station is moving).The Channel Change Count field indicates how many Target Beacon Frame Transmission Time (TBTT) is required by the station to send the item to change to the new channel. If the Channel Change Count field is set to 0, this indicates that the change occurs before the next TBTT. If the Channel Change Count field is set to 1, this indicates that the change can occur at any time after the item is sent (the Channel Change Count field indicates the number of Target Beacon Frame Transmission Time (TBTT) until the station sending the Channel Change Count field switches to the new channel). A Channel Change Count field set to 1 indicates that the change occurs immediately before the next TBTT.A Channel Change Count field set to 0 indicates that the change occurs at any time after the box containing the Channel Change Count field is transmitted. Figure 11B is a schematic diagram of a box structure for an extended channel switch advertisement element inclusion, according to a modality of this application. As shown in Figure 11B, the extended channel switch advertisement element inclusion includes a Channel Switch Mode field, a New Operating Class field, a New Channel Number field, and a Channel Switch Count field. The Channel Switch Mode field indicates a transmission restriction before the channel switch. The New Operating Class field indicates a set of operations to which the station switches (the New Operating Class field is set to the operating class number after the channel switch). The New Channel Number field indicates a channel number to which the station will switch.The channel change count field indicates the number of TBTTs required after an item is sent by the station to change to the channel. If the channel change count field is set to 0, this indicates that the change occurs before the next TBTT. If the channel change count field is set to 1, this indicates that the change can occur at any time after the item is sent. Figure 11C is a schematic diagram of a box structure for a wideband channel switch element inclusion, according to a modality of this application. As shown in Figure 11C, the wideband channel switch element inclusion includes a New Channel Width field, a New Channel Center Frequency Segment 0 field, and a New Channel Center Frequency Segment 1 field. The New Channel Width field defines a BSS bandwidth. The new channel 0 center frequency segment defines a center frequency for a BSS bandwidth of 20, 40, 80, 160, or 80+80 MHz (New Channel 0 Center Frequency Segment Defines a channel center frequency for a BSS of 20, 40, 80, 160, or 80+80 MHz).The center frequency segment of new channel 1 defines a center frequency of a BSS bandwidth of 160 or 80 + 80 MHz (Center Frequency Segment of New Channel 1 Defines a channel center frequency for a BSS of 160 or 80+80 MHz). Figure 11D is a schematic diagram of a Quiet Element box structure according to one modality of this application. As shown in Figure 11D, the Quiet Element includes a Quiet Count field, a Quiet Period field, a Quiet Duration field, and a Quiet Offset field. The Quiet Count field ML / 1 / ¿UZÓ / UÓUO4O is set to a number of TBTTs, up to a radio beacon interval during which the next quiet interval begins (the Quiet Count field is set to the number of TBTTs up to the radio beacon interval during which the next quiet interval begins). The Quiet Period field is set to a number of 5 radio beacon frame intervals between the start of regularly scheduled quiet intervals defined by the quiet element. A Quiet Period field set to 0 indicates that no periodic quiet interval is defined (the Quiet Period field is set to the number of radio beacon intervals between the start of regularly scheduled quiet intervals defined by this quiet element. A Quiet Period field set to 0 indicates that no periodic quiet interval is defined).The Quiet Duration field is set to the duration of the quiet interval, in TU units (the Quiet Duration field is set to the duration of the quiet interval, expressed in TU). The Quiet Compensation field is set to the offset of the start of the TBTT quiet interval specified by the Quiet Count field, in TU units. A Quiet Compensation field value less than one beacon frame interval (the Quiet Compensation field is set to the offset of the start of the TBTT quiet interval specified by the Quiet Count field, expressed in TU. The Quiet Compensation field value is less than one beacon frame interval). It can be understood that, after the quiet element takes effect, the APya does not communicate with the STA, and the STA maintains a quiet state, so that the STA can execute another operation. Optionally, the second MLD AP is an MLD AP to which a non-broadcast AP belongs in the multiple BSSID set including the second AP. Specifically, for the meaning of the second MLD AP, refer to the related description in Mode 25 above 1. S202: The second AP in the first MLD AP sends the second frame on a link on which the second AP works. The second AP in the first MLD AP needs to send, on the link where the second MLD AP operates, the second frame to a non-AP MLD associated with the first MLD AP or to a station around the second AP. The stations around the second AP include a station managed by the second AP and a non-associated station. It can be understood that the second frame can be sent in a broadcast, multicast, or unicast manner. S203: A second non-AP MLD STA receives the second frame on a link on which the second STA is working. The second STA can be a station managed by the second AP or a station around the second AP, and it can learn from critical BSS parameters specific to a ML / 1 / ZUZÓ / UÓUO4O plurality of APs in an MLD AP associated with an MLD including the first STA. The second STA and the second AP work on the same link / frequency band / channel. S204: The second STA of the non-AP MLD analyzes the second chart to obtain 5 critical BSS parameters specific to a plurality of APs in an AP MLD associated with the non-AP MLD. Specifically, after receiving the second frame, the second STA of the non-AP MLD can analyze the second frame to obtain, from an ML element of the second frame, critical BSS parameters specific to K APs (KAPs have an association relationship with the non-AP MLD, and K is a positive integer) in the AP MLD associated with the non-AP MLD. For each AP-specific critical BSS parameter in the KAPs, the non-AP MLD can adjust, based on an indication of each AP-specific critical BSS parameter, channel information from a STA corresponding to each AP. For example, as shown in FIGURE 4, AP 2x is assumed to be the second AP, MLD AP 2 is the first MLD AP, and both MLD AP 1 and MLD AP 3 are the second MLD AP. Non-AP MLD 1 is assumed to be associated with AP 1x and AP 2y of MLD AP 1, K is equal to 2, and the APs that have an association relationship with non-AP MLD 1 are AP 1x and AP 2y. The second table separately carries critical BSS parameters specific to a plurality of APs (which may be all APs or some APs) in MLD AP 1, MLD AP 2, and MLD AP 3. For example, the second table carries critical BSS parameters specific to all APs in MLD AP 1, and also carries critical parameters specific to all APs in MLD AP 2 and MLD AP 3.Therefore, for AP 1x in MLD AP 1, assuming that the critical BSS parameter specific to AP 1x indicates that the station will switch to channel number 9, MLD non-AP 1 switches, based on the indication of the critical BSS parameter 25 specific to AP 1x, a STA corresponding to AP 1x to a channel where channel number 9 is located for communication. For AP 2y in MLD AP 1, assuming that a critical BSS parameter specific to AP 2y indicates that the station will switch to an operational class A, MLD non-AP 1 switches, based on an indication of the critical BSS parameter specific to AP 2y, a STA corresponding to AP 2y from its current operational class to an operational class A. It can be understood that in Mode 2 of this application, an AP in the MLDAP is used as an example for description purposes. In the actual application, each AP in the MLDAP can execute steps S201 through S202 as shown in Figure 9. It can be understood that the second STA can be a single-link STA, or it can be an STA in a non-AP MLD. When the second STA is a single-link STA, when the second STA switches from one link to another for operation, the second STA can ML / 1 / ZUZÓ / UÓUO4O obtain a specific critical BSS parameter using the method in this mode of this request. It can be learned that, in this mode of this request, a second frame sent by the AP in the MLD AP not only explicitly carries critical BSS parameters specific to a plurality of APs in the MLD AP, but also explicitly carries critical BSS parameters specific to a plurality of APs in another MLD AP. The specific critical BSS parameter includes an element related to a channel switch. This can help the non-AP MLD know the operational channel switch status of all APs in the MLD AP in real time when the non-AP MLD is listening on one or more links (not all links), so that the non-AP MLD can function normally. In an optional mode, when the STA on the non-AP MLD requests a switch to another link for operation, the channel switch signaling implicitly requests a specific critical BSS parameter from the MLD AP operating on the link. Alternatively, specific signaling is explicitly carried to indicate a specifically required critical BSS parameter. For example, one or more Element IDs are used. Optionally, one or more element ID extensions are carried in addition. Alternatively, a non-legacy element in the 802.11-2016 protocol is directly reused to obtain a parameter from a corresponding element in the non-legacy element. A response frame with which the associated MLD AP responds on link 20 corresponding to the STA needs to carry a specific BSS parameter from an AP operating on the other link at that time. Optionally, the channel change signaling also includes an AP identifier, for example, a link identifier; and an MLD identifier including the AP, for example, an MLD sequence number or an MLD MAC address. Figure 12 is a schematic diagram of a box structure for a non-inherited element according to one modality of this request. As shown in Figure 12, the non-inherited element includes an Element ID, a Length, an Element ID Extension, one or more Element IDs, and one or more Element ID Extensions. The Element ID and Element ID Extension are used to indicate that the element is the non-inherited element. The Length indicates a length after an Element Length field. Optionally, the Element ID(s) and Element ID Extension(s) are used to indicate the content of one or more specific requested elements. An Element ID Extension number also exists only when an Element ID value is 255. Otherwise, the Element ID can independently indicate an element. ML / 1 / ¿UZÓ / UÓUO4O The content above describes in detail the methods provided in this application. To better implement the above solutions in modalities of this application, modalities of this application additionally provide corresponding apparatus or devices. In the modalities of this application, functional modules in the multi-link device 5 can be defined based on the examples in the previous method. For example, each functional module can be defined as corresponding to each function, or two or more functions can be integrated into a single processing module. The integrated module can be implemented in hardware form or as a software functional module. It should be noted that, in the modalities of this application, the division into modules 10 is an example and is simply a logical function division. In an actual implementation, a different method of division can be used. The following describes in detail the communication devices in the modalities of this application with reference to Figures 13 through 17. The communication device is an access point in an access-point multi-link device or a station in a non-access-point multi-link device. Furthermore, the communication device can be a device in an MLD AP, or a device in a non-AP MLD. When an integrated unit is used, FIGURE 13 is a schematic diagram of the structure of a communication device 1 according to one modality of this application. The communication device 1 may be a first MLD AP or a chip in a first MLD AP, for example, a Wi-Fi chip, or it may be a first AP in a first MLD AP or a chip in a first AP. The first AP is a reporting AP and belongs to the first MLD AP. As shown in FIGURE 13, the communication device 1 includes a processing unit 11 and a transceiver unit 12. The processing unit 11 is configured to generate a first frame, where 25 the first frame contains critical BSS parameter update information corresponding to a plurality of APs in a first MLD AP and critical BSS parameter update information corresponding to a plurality of APs in a second MLD AP. The second MLD AP is an MLD AP to which a non-transmitting AP belongs in a multiple BSSID set including a first AP, and a piece of critical BSS parameter update information 30 corresponding to an AP is used to determine whether a critical BSS parameter in a BSS managed by the AP is up to date. The transceiver unit 12 is configured to send the first frame on a link on which communication apparatus 1 is operating. Optionally, the critical BSS parameter update information includes a 35 critical BSS parameter update count value. It can be learned that in communication device 1, the first frame generated by The processing unit 11 can not only indicate critical BSS parameter update count values ​​corresponding to the plurality of APs in the first MLD AP, but can also indicate critical BSS parameter update count values ​​corresponding to the plurality of APs in the second MLD AP. This implements that one AP assists a plurality of APs in another MLD AP in indicating corresponding critical BSS parameter update count values, so that a STA can compare a currently received critical BSS parameter update count value with a critical BSS parameter update count value received last time, and can check if a critical BSS parameter is up to date.Therefore, the STA can be assisted in receiving a final critical BSS parameter, and a non-AP MLD associated with the second MLD AP can listen on a link where a non-transmitting AP is working on the second MLDAP, and can also work normally. Optionally, processing unit 11 is further configured to generate a second frame, where the second frame indicates critical BSS parameters specific to a plurality of APs in the first MLD AP and critical BSS parameters specific to a plurality of APs in the second MLD AP. Transceiver unit 12 is further configured to send the second frame on a link on which communication apparatus 1 is operating. It should be understood that communication apparatus 1 can correspondingly execute Mode 1, and the above operations or unit functions in communication apparatus 1 are used separately to implement corresponding operations of the first AP in the first MLD AP in Mode 1. For brevity, the details are not described again here. Figure 14 is a schematic diagram of a communication device 2 structure according to one modality of this application. The communication device 2 may be a first STA or a chip within a first STA, for example, a Wi-Fi chip. The first STA may be a single-link STA or an STA within a non-AP MLD. As shown in Figure 14, the communication device 2 includes a transceiver unit 21 and a processing unit 22. Transceiver unit 21 is configured to receive a first frame on a link operated by communication device 2. This first frame contains critical BSS parameter update information corresponding to a plurality of APs in the first MLD AP and critical BSS parameter update information corresponding to a plurality of APs in a second MLD AP. The second MLD AP is an MLD AP to which an AP not transmitting belongs within a multiple BSSID set, including the first AP. A piece of critical BSS parameter update information corresponding to an AP is used to determine if a critical BSS parameter in a BSS managed by that AP is present. ML / 1 / ¿UZÓ / UÓUO4O is updated. Processing unit 22 is configured to determine, based on the first frame, whether critical BSS parameters of a plurality of BSS managed by a plurality of APs in an MLD AP associated with communication apparatus 2 are updated. Optionally, the critical BSS parameter update information includes a 5 critical BSS parameter update count value. It can be learned that in communication apparatus 2, processing unit 22 can know, based on the critical BSS parameter update count value indicated by the first box, whether the BSS to which processing unit 22 belongs is updated with a critical BSS parameter, to ensure that processing unit 22 10 can receive a final critical BSS parameter. Optionally, the transceiver unit 21 is further configured to receive a second frame on a link operated by communication apparatus 2, where the second frame indicates critical BSS parameters specific to a plurality of APs in the first MLD AP and critical BSS parameters specific to a plurality of APs in the second MLD AP. The processing unit 22 is configured to analyze the second frame to obtain critical BSS parameters specific to a plurality of APs in an MLD AP associated with communication apparatus 2. It should be understood that communication apparatus 2 can correspondingly execute Mode 1, and the previous operations or functions of the units in communication apparatus 2 are separately used to implement corresponding operations of the first STA in the non-AP MLD in Mode 1. For brevity, the details are not described again here. Figure 15 is a schematic diagram of a communication device 3 structure according to one modality of this application. The communication device 3 can be a first MLD AP or a chip in a first MLD AP, for example, a Wi-Fi chip, or it can be a second AP in a first MLD AP or a chip in a second AP. The second AP is any AP in the first MLD AP. As shown in Figure 15, the communication device 3 includes a processing unit 31 and a transceiver unit 32. The processing unit 31 is configured to generate a second frame, 30, where the second frame indicates critical BSS parameters specific to a plurality of APs in the first MLD AP and / or critical BSS parameters specific to a plurality of APs in the second MLD AP. The second MLD AP is an MLD AP to which an AP not transmitting in a multiple BSSID set belongs, including the second AP. The transceiver unit 32 is configured to send the second frame on a link on which communication device 35 is operating. It can be learned that, in communication device 3, the second generated frame ML / 1 / ZUZÓ / UÓUO4O by processing unit 31 not only explicitly carries the critical BSS parameters specific to the plurality of APs in the MLD AP, but also explicitly carries the critical BSS parameters specific to the plurality of APs in another MLD AP. The specific critical BSS parameter includes an element related to a channel change. This can help the non-AP MLD know the operating channel change status of all APs in the MLD AP in time when the non-AP MLD is listening to one or more links (not all links), so that the non-AP MLD can function normally. It should be understood that the communication apparatus 3 described in this modality of this application can correspondingly execute Modality 2, and the operations or 10 functions above of the units in communication apparatus 3 are separately used to implement corresponding operations of the second AP in the first MLD AP in Modality 2. For brevity, the details are not described again here. Figure 16 is a schematic diagram of a communication device 4 structure according to one modality of this application. The communication device 4 15 may be a second STA or a chip in a second STA, for example, a Wi-Fi chip. The second STA may be a single-link STA, or it may be an STA in a non-AP MLD. As shown in Figure 16, the communication device 4 includes a transceiver unit 41 and a processing unit 42. Transceiver unit 41 is configured to receive a second frame on a link 20 on which communication apparatus 4 operates, where the second frame indicates critical BSS parameters specific to a plurality of APs in a first MLD AP and / or critical BSS parameters specific to a plurality of APs in a second MLD AP. The second MLDAP is an MLDAP to which an AP not transmitting in a multiple BSSID set, including the second AP, belongs. Processing unit 42 is configured to analyze the second frame to obtain critical BSS parameters specific to a plurality of APs in an MLD AP associated with the second STA. It can be learned that in communication apparatus 4, processing unit 42 analyzes the second frame to learn a final critical BSS parameter from the plurality of APs in an MLDAP associated with an MLD in which processing unit 30 42 is located, and can execute corresponding processing based on the final critical BSS parameter received, to ensure normal communication. It should be understood that the communication apparatus 4 described in this modality of this application can correspondingly execute Modality 2, and the above operations or functions of the units in communication apparatus 4 are separately used to implement corresponding operations of the second STA of the non-AP MLD in Modality 2. For brevity, the details are not described again here. ML / 1 / ¿UZÓ / UÓUO4O The foregoing describes the MLD AP and STA in the forms covered by this application. The following describes possible product forms of the MLD AP and STA. It should be understood that any product form having the function of the MLD AP in FIGURE 13 or FIGURE 15 and any product form having the function of the STA in FIGURE 14 or FIGURE 16 falls within the scope of protection of the forms covered by this application. Furthermore, it should be understood that the following description is merely an example, and the product forms of the MLD AP and STA in the forms covered by this application are not limited to it. As a possible product form, the MLD AP and STA described in the modalities of this application can be implemented using a general bus architecture. Figure 17 is a schematic diagram of a communication apparatus 1000 structure according to one modality of this application. The communication apparatus 1000 may be an MLD AP, an STA, or an apparatus within an MLD AP or an STA. As shown in Figure 17, the communication apparatus 1000 includes a processor 1001 and a transceiver 1002 that is internally connected to and communicates with the processor. The processor 1001 is a general-purpose processor, a dedicated processor, or the like. For example, the processor may be a baseband processor or a central processing unit.The baseband processor can be configured to process a communication protocol and communication data, and the central processing unit can be configured to control a communication device (e.g., a base station, a baseband chip, a terminal, a terminal chip, a DU, or a CU) to execute a computer program or to process computer program data. The 1002 transceiver can be referred to as a transceiver unit, a transceiver, a transceiver circuit, or similarly, and is configured to implement a transceiver function. The 1002 transceiver can include a receiver and a transmitter. The receiver can be referred to as a receiving machine, a receiving circuit, or similarly, and is configured to implement a receiving function. The transmitter can be referred to as a transmitting machine, a transmitting circuit, or similarly, and is configured to implement a transmitting function.Optionally, the communication device 1000 may also include an antenna 1003 and / or a radio frequency unit (not shown in the figure). The antenna 1003 and / or the radio frequency unit may be located inside the communication device 1000, or they may be separate from the communication device 1000. In other words, the antenna 1003 and / or the radio frequency unit may be deployed remotely or in a distributed manner. Optionally, the communication device 1000 may include one or more memories 1004. Memory 1004 can store instructions. The instructions may be a computer program. The computer program can run on the communication device 1000, so that the communication device 1000 executes the described method. ML / 1 / ¿UZÓ / UÓUO4O in the modes of the previous method. Optionally, memory 1004 can also store data. The communication device 1000 and memory 1004 can be separately located, or they can be integrated. The processor 1001, the transceiver 1002, and the memory 1004 can be connected to 5 via a communication bus. In one design, the communication device 1000 can be configured to perform a function of the first AP on the first MLD AP in Mode 1 above. The processor 1001 can be configured to perform step S101 in Figure 7 and / or another process of the technology described in this specification. The transceiver 1002 can be configured to perform step S102 in Figure 7 and / or another process of the technology described in this specification. In one design, the communication device 1000 can be configured to perform a function of the first STA of the non-AP MLD in Mode 1. The processor 1001 can be configured to perform step S104 in FIGURE 7 and / or another process of the technology described in this specification. The transceiver 1002 can be configured to perform step S103 in FIGURE 7 and / or another process of the technology described in this specification. In one design, the communication device 1000 can be configured to perform a function of the second AP on the first MLD AP in Mode 2. The processor 1001 can be configured to perform step S201 in FIGURE 9 and / or another process of the technology described in this specification. The transceiver 1002 can be configured to perform step S202 in FIGURE 9 and / or another process of the technology described in this specification. In one design, the communication device 1000 can be configured to execute a function of the non-AP MLD STA in Mode 2. The processor 1001 can be configured to execute step S204 in FIGURE 9 and / or another process of the technology described in this specification. The transceiver 1002 can be configured to execute step S203 in FIGURE 9 and / or another process of the technology described in this specification. In any of the above designs, the 1001 processor can include a transceiver configured to perform send and receive functions. For example, the transceiver can be a transceiver circuit, an interface, or an interface circuit. The transceiver circuit, interface, or interface circuit configured to perform send and receive functions can be separate or integrated. The transceiver circuit, interface, or interface circuit can be configured to read and / or write code / data. Alternatively, the transceiver circuit, interface, or interface circuit can be configured to transmit or transfer a signal. In any of the above designs, the 1001 processor can store instructions. The instruction can be a computer program. The program of The computer program ML / 1 / ZUZÓ / UÓUO4O is run on processor 1001, so that communication device 1000 can execute the method described in the previous method's modalities. The computer program can be fixed on processor 1001, and in this case, processor 1001 can be implemented in hardware. In one implementation, the communication apparatus 1000 may include a circuit, and the circuit may implement a transmit, receive, or communicate function in any of the modes of the preceding method. The processor and transceiver described in this application may be implemented on an integrated circuit (IC), an analog IC, a radio frequency integrated circuit (RFIC), a mixed-signal IC, an application-specific integrated circuit (ASIC), or a printed circuit board (PCB), an electronic device, and the like.The processor and transceiver can be fabricated using various IC technologies, for example, a complementary metal oxide semiconductor (CMOS), an N-type metal oxide semiconductor (NMOS), a positive channel metal oxide semiconductor (PMOS), a bipolar junction transistor (BJT), a bipolar CMOS (BICMOS), silicon germanium (SiGe), and gallium arsenide (GaAs). The scope of the communication apparatus described in this application is not limited to that shown, and the structure of the communication apparatus cannot be limited by FIGURE 17. The communication apparatus may be a standalone device or it may be part of a larger device. For example, the communication apparatus may be: (1) a stand-alone integrated circuit IC, a chip, or a system-on-chip or subsystem; (2) an assembly including one or more ICs, wherein, optionally, the IC assembly may further include a storage component configured to store data and a computer program; (3) an ASIC, for example, a modem (Modem); (4) a module that can be incorporated into another device; (5) a receiver, a terminal, a smart terminal, a cell phone, a wireless device, a handheld device, a mobile unit, a vehicle-mounted device, a network device, a cloud device, an artificial intelligence device, or the like; or (6) another device or the like. In one possible product form, MLDAP and STA in modalities of this request can be implemented by a general-purpose processor. The general-purpose processor for implementing MLDAP includes a processing circuit and an input / output interface internally connected to and communicating with the processing circuit. In one design, the general-purpose processor can be configured to execute a function of the first AP in the first MLD AP in the mode described above. Specifically, the processing circuit is configured to execute step S101 in Figure 7 and / or another process of the technology described in this specification. The input / output interface is configured to execute step S102 in Figure 7 and / or another process of the technology described in this specification. In another design, the general-purpose processor can be configured to execute a function of the second AP on the first MLD AP in Mode 2 above. Specifically, the processing circuit is configured to execute step S201 in Figure 9 and / or another process of the technology described in this specification. The input / output interface is configured to execute step S202 in Figure 9 and / or another process of the technology described in this specification. The general-purpose processor for implementing the non-AP MLD includes a processing circuit and an internally connected input / output interface communicating with the processing circuit. In one design, the general-purpose processor can be configured to execute a function of the first STA of the non-AP MLD in Mode 1. Specifically, the processing circuit is configured to execute step S104 in Figure 7 and / or another process of the technology described in this specification. The input / output interface is configured to execute step S103 in Figure 7 and / or another process of the technology described in this specification. In another design, the general-purpose processor can be configured to execute a function of the second STA of the non-AP MLD in Mode 2. Specifically, the processing circuit is configured to execute step S204 in Figure 9 and / or another process of the technology described in this specification. The input / output interface is configured to execute step S203 in Figure 9 and / or another process of the technology described in this specification. As a possible product form, the MLDAP or STA described in this modality of this application may also be implemented using the following components: one or more FPGAs (field programmable gate arrays), a PLD (programmable logic device), a controller, a state machine, gate logic, a discrete hardware component, any other convenient circuit, or any combination of circuits that can perform various functions described in this application. It should be understood that the communication devices in the various forms of the 35 products mentioned above have any function of the MLD AP or STA in the method modalities. The details are not described again here. ML / 1 / ¿UZÓ / UÓUO4O One form of this request also provides a computer-readable storage medium. The computer-readable storage medium stores computer program code. When the processor executes the computer program code, an electronic device executes the method in any of the five modes described above. One form of this request also provides a computer program product. When the computer program product runs on a computer, the computer is enabled to execute the method in any of the above forms. One modality of this application further provides a communication device. The device may exist in a one-chip product form. One device structure includes a processor and an interface circuit. The processor is configured to communicate with another device through the interface circuit, to enable the device to execute the method in any of the above modalities. One modality of this application further provides a wireless communication system, including a first MLD AP and a STA. The first MLD AP and the STA can execute the method in any of the above modalities. The steps of the method or algorithm described in combination with the content disclosed in this application may be implemented by hardware, or they may be implemented by a processor executing software instructions. The software instructions may include a corresponding software module. The software module may be stored in random access memory (RAM), flash memory, erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), a register, a hard disk, a removable hard disk, a compact disc read-only memory (CD-ROM), or any other form of storage medium widely known in the art.For example, a storage medium is coupled to a processor so that the processor can read information from the storage medium or write information to the storage medium. The storage medium can certainly be a component of the processor. The processor and the storage medium can be placed in an ASIC. Furthermore, the ASIC can be located in a core network interface device. The processor and the storage medium can certainly exist as discrete components within the core network interface device. A person skilled in the art should be aware that in one or more of the preceding examples, the functions described in this application may be implemented by hardware, software, firmware, or any combination thereof. When the functions are implemented by software, the above functions may be stored on a computer-readable medium or may be transmitted as one or more instructions or code on a computer-readable medium. The computer-readable medium includes a computer-readable storage medium and a communication medium, where the communication medium includes any means that facilitates the transmission of a computer program from one location to another. The storage medium may be any available medium accessible to a general-purpose or special-purpose computer. In the specific implementations above, the objectives, technical solutions, and beneficial effects of this application are further described in detail. It should be understood that the above descriptions are merely specific implementations of this application, but are not intended to limit the scope of protection of this application. Any modification, equivalent replacement, improvement, or similar action based on the technical solutions of this application shall fall within the scope of protection of this application.

Claims

1. A method for updating a critical Basic Service Set (BSS) parameter, characterized in that it comprises: generating, through an access point (AP) in a first multi-link access point device (MLD AP), a frame, wherein the second frame indicates at least one of the following parameters: critical BSS parameters specific to a plurality of APs in the first MLD AP, critical BSS parameters specific to a plurality of APs in a second MLD AP, and the second MLD AP is an MLD AP to which an AP not broadcasting belongs in a multiple Basic Service Set Identifier (BSSID) comprising the second AP; and sending, through the second AP in the first MLD AP, the second frame on the link on which the second AP operates.

2. A method for updating a specific critical Basic Service Set (BSS) parameter, characterized in that it comprises: receiving, through a station (STA), a frame on a link on which a second STA operates, wherein the second frame indicates at least one of the following parameters: specific critical BSS parameters of a plurality of access points (APs) on a first multi-link access point device (MLD AP), specific critical BSS parameters of a plurality of APs on a second MLD AP, and the second MLD AP is an MLDAP to which an AP not broadcast on a multiple Basic Service Set Identifier (BSSID) belongs, comprising an AP broadcast on the first MLDAP; and analyzing, through the STA, the frame to obtain specific critical BSS parameters of a plurality of APs on an MLDAP associated with the STA.

3. The method according to claim 1 or 2, characterized in that a specific critical BSS parameter of an AP in the box comprises one or more of the following: 25 an inclusion of a channel change advertisement element, an inclusion of an extended channel change advertisement element, an inclusion of a wideband channel change element, and an inclusion of a channel change wrapper element.

4. The method in accordance with any of claims 1 to 3, characterized in that the critical BSS parameter specific to an AP in the box further comprises one or more of the following: an inclusion of a quiet element and an inclusion of a quiet channel element.

5. The method in accordance with any of claims 1 to 4, characterized in that the specific critical BSS parameter is carried in a multi-link element, ML.

6. A communication apparatus, characterized in that it comprises: 35 a processing unit, configured to generate a frame, wherein the frame indicates at least one of the following parameters: critical BSS parameters, MLD / 1 / ZUZÓ / UÓUO4O specific to a plurality of access points, APs, in a first multi-link access point device, MLD AP; critical BSS parameters specific to a plurality of APs in a second MLD AP; and the second MLD AP is an MLD AP to which belongs an AP not transmitted in a multiple BSSID set comprising the communication apparatus as a transmitted AP in the first MLD AP; and a transceiver unit, configured to send the frame on a link on which the communication apparatus operates.

7. A communication apparatus, characterized in that it comprises: a transceiver unit, configured to receive a frame on a link on which the transceiver unit operates, wherein the frame indicates at least one of the following parameters: critical Basic Service Set (BSS) parameters specific to a plurality of access points (APs) in a first multi-link access point device (MLD AP), critical BSS parameters specific to a plurality of APs in a second MLD AP, and the second MLD AP is an MLD AP to which an AP not transmitted belongs in a multiple Basic Service Set Identifier (BSSID) set comprising an AP transmitted in the first MLD AP; and a processing unit, configured to analyze the frame to obtain critical BSS parameters specific to a plurality of APs in an MLD AP associated with the communication apparatus.

8. The communication apparatus according to claim 6 or 7, characterized in that a critical BSS parameter specific to an AP in the box comprises one or more of the following: an inclusion of a channel change announcement element, an inclusion of an extended channel change announcement element, an inclusion of a wideband channel change announcement element, and an inclusion of a channel change wrapper element.

9. The communication apparatus according to any of claims 6 to 8, characterized in that the critical BSS parameter specific to an AP in the box further comprises one or more of the following: an inclusion of a quiet element and an inclusion of a quiet channel element.

10. The communication apparatus according to any of claims 6 to 9, characterized in that the specific critical BSS parameter is carried in a multilink element, ML.

11. A computer-readable storage medium, characterized in that the computer-readable storage medium stores instructions, and when the instructions are run on a computer, the computer is enabled to execute the method in accordance with any one of claims 1 to 5.

12. A computer program product characterized in that it comprises instructions, wherein, when the instructions are run on a computer, the computer is enabled to execute the method in accordance with any one of claims 1 to 5.

13. A chip or chip system, characterized in that it comprises an input / output interface and a processing circuit, wherein the input / output interface is configured to receive code instructions and transmit the code instructions to the processing circuit, and the processing circuit is configured to run the code instructions to execute the method in accordance with any one of claims 1 to 5.

14. A first multi-link access point device, MLD AP, characterized in that it comprises a first access point, AP, and a second AP, the second AP comprising a processing unit and a transceiver unit, wherein the transceiver unit and the processing unit are configured to execute the method in accordance with any of claims 1, 3 to 5.

15. A first non-access point multi-link device, MLD no-AP, characterized in that it comprises a first station, STA, and a second STA, the second STA comprising a processing unit and a transceiver unit, wherein the transceiver unit and the processing unit are configured to execute the method in accordance with any of claims 2 to 5.

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