Communication method and apparatus

Abstract

A communication method and apparatus, which relate to the field of communications, and enable a non-access point multi-link device to accurately execute seamless roaming, thereby improving the reliability of communications. The method comprises: an access point multi-link device acquiring first information, wherein the first information indicates the type of a seamless mobility domain (SMD) to which the access point multi-link device belongs, and the type of the SMD is a central SMD or a distributed SMD; and sending the first information to a non-access point multi-link device. Correspondingly, the non-access point multi-link device receives the first information, and executes, on the basis of the first information, a roaming procedure (corresponding to the type of the SMD indicated by the first information). The solution of the present application can be widely applied to the technical fields of communications, artificial intelligence, the Internet of Vehicles, intelligent home networking, etc.

Description

Communication methods and devices

[0001] This application claims priority to Chinese Patent Application No. 202510212014.8, filed on February 24, 2025, entitled "Communication Method and Apparatus", and to Chinese Patent Application No. 202510272895.2, filed on March 7, 2025, entitled "Communication Method and Apparatus", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of communications, and more particularly to communication methods and apparatus. Background Technology

[0003] Roaming refers to the ability of a wireless terminal, such as a non-access point multi-link device (non-AP MLD), to switch from its current AP MLD to an AP MLD with better signal quality or service, such as a target AP MLD, when moving within a network covered by multiple access point multi-link devices (AP MLDs), without interrupting network connectivity or affecting application operation. The current AP MLD refers to the AP MLD currently providing service to the non-AP MLD.

[0004] Currently, a low-latency roaming method has been proposed: seamless roaming. Seamless roaming refers to the ability of a non-AP MLD to quickly and freely switch from the current AP MLD to the target AP MLD while moving. Under seamless roaming, the switching time between AP MLDs for a non-AP MLD can be controlled within milliseconds, with virtually no packet loss.

[0005] However, how to effectively implement seamless roaming in a non-AP MLD is a problem that urgently needs to be solved. Summary of the Invention

[0006] This application provides a communication method and apparatus that enables non-AP MLDs to accurately perform seamless roaming and improve roaming performance.

[0007] Firstly, a communication method is provided. This method can be executed by an AP MLD (Access Point Management Lever), a component of the AP MLD (such as its processor, chip, or chip system), or a logic module or software capable of implementing all or part of the AP MLD's functions. The method includes: acquiring first information, which indicates the type of seamless mobility domain (SMD) to which the AP MLD belongs, wherein the SMD type is a centralized SMD or a distributed SMD; and transmitting the first information.

[0008] In this application, AP MLD refers to an access point multi-link device that supports providing services to non-AP MLDs. For example, AP MLDs include the current AP MLD and neighboring AP MLDs. Neighboring AP MLDs include the target AP MLD. Based on the method described in the first aspect, the non-AP MLD can execute the roaming procedure corresponding to the type of SMD indicated by the first information from the current AP MLD, enabling the non-AP MLD to execute the roaming procedure that meets the requirements of the AP MLD and thereby improving roaming performance.

[0009] In one possible design, the method of the first aspect further includes: sending second information indicating whether the location of the AP MLD is located at the edge of the seamless mobility domain to which the AP MLD belongs.

[0010] Based on this possible design, when the AP MLD is the current AP MLD, the non-AP MLD can determine whether the current AP MLD is located at the edge of its SMD. Then, if the non-AP MLD determines that the current AP MLD is at the edge of its SMD, it can preemptively perform pairwise temporary key renegotiation and installation with the target AP MLD via the current AP MLD. This avoids the situation where the non-AP MLD cannot determine whether the current AP MLD is at the edge of its SMD, and therefore cannot determine the timing for performing pairwise temporary key renegotiation and installation with the target AP MLD. This prevents the non-AP MLD from independently performing these operations after disconnection from the current AP MLD, thus increasing the data interruption time for the non-AP MLD.

[0011] In one possible design, when the AP MLD is a neighboring AP MLD that is a non-AP MLD, the method of the first aspect further includes: sending third information to indicate whether the SMD to which the neighboring AP MLD belongs is the same as the SMD to which the current AP MLD belongs.

[0012] Based on this possible design, the non-AP MLD can better select a suitable neighboring AP MLD as the target AP MLD based on third information. For example, the non-AP MLD determines whether the SMD to which each neighboring AP MLD belongs is the same as the SMD to which the current AP MLD of the non-AP MLD belongs based on the third information of each neighboring AP MLD. Since the non-AP MLD does not need to regenerate or negotiate the pair of temporary keys when switching between two AP MLDs within the same SMD, it can prioritize selecting a neighboring AP MLD belonging to the same SMD as the target AP MLD to reduce the latency of the roaming handover process.

[0013] In one possible design, the method of the first aspect further includes: sending fourth information for providing information about the neighboring AP MLDs of the non-AP MLD; the fourth information includes at least one of a robust secure network sub-element, a robust secure network extension sub-element, a supported rate and basic service set member selector sub-element, and an extended supported rate and basic service set member selector sub-element.

[0014] Based on this possible design, non-AP MLDs can directly obtain relevant information about neighboring AP MLDs through the fourth information. Compared to non-AP MLDs obtaining neighboring AP MLD information by scanning neighboring AP MLDs over the air interface, this reduces latency and improves roaming performance.

[0015] In one possible design, the first information is carried in any one of the following: a beacon frame, a probe request frame, a neighbor report element, or a newly defined seamless mobility domain element; the newly defined seamless mobility domain element is used to carry information related to the SMD to which the AP MLD belongs.

[0016] Based on this possible design, various information formats can be provided to carry the first information, thereby enhancing the diversity and flexibility of the first information transmission.

[0017] In one possible design, the second information is carried in any of the extended service set reporting element, the mobile domain element, or the newly defined seamless mobile domain element.

[0018] Based on this possible design, various types of information can be provided to carry the second information, thereby enhancing the diversity and flexibility of the second information transmission.

[0019] Secondly, a communication method is provided. This method can be executed by a non-AP MLD, or by a component of the non-AP MLD, such as a processor, chip, or chip system of the non-AP MLD, or by a logic module or software capable of implementing all or part of the functions of the non-AP MLD. The method includes: receiving first information, the first information indicating the type of SMD to which the AP MLD belongs, wherein the SMD type is a centralized SMD or a distributed SMD; and, based on the first information, executing a roaming procedure corresponding to the type of SMD indicated by the first information.

[0020] Based on the method described in the second aspect, the non-AP MLD can execute a roaming process that meets the AP MLD requirements based on the first information from the current AP MLD in the first information, and determine an improvement in roaming performance.

[0021] In one possible design, if the type of SMD indicated by the first information is a centralized SMD, the roaming process corresponding to the SMD type is a centralized SMD roaming process; if the type of SMD indicated by the first information is a distributed SMD, the roaming process corresponding to the SMD type is a distributed SMD roaming process.

[0022] Based on this possible design, the non-AP MLD can accurately execute the roaming process of a centralized SMD or a distributed SMD based on the type of SMD indicated by the first information of the current AP MLD, thereby improving roaming performance.

[0023] In one possible design, the method of the second aspect further includes: receiving second information indicating whether the location of the AP MLD is located at the edge of the SMD to which the AP MLD belongs.

[0024] Based on this possible design, the non-AP MLD can determine whether the current AP MLD is located at the edge of its assigned SMD. If the non-AP MLD determines that the current AP MLD is at the edge of its SMD, it can preemptively perform pairwise temporary key renegotiation and installation with the target AP MLD via the current AP MLD. This avoids the situation where the non-AP MLD cannot determine whether the current AP MLD is at the edge of its SMD, thus preventing it from determining the timing for performing pairwise temporary key renegotiation and installation with the target AP MLD. This would prevent the non-AP MLD from independently performing these operations after disconnection from the current AP MLD, increasing the data interruption time for the non-AP MLD.

[0025] In one possible design, when the AP MLD is a neighboring AP MLD of the non-AP MLD, the second aspect of the method further includes: receiving third information indicating whether the SMD to which the neighboring AP MLD belongs is the same as the SMD to which the current AP MLD of the non-AP MLD belongs.

[0026] Based on this possible design, the non-AP MLD can better select a suitable neighboring AP MLD as the target AP MLD based on third information. For example, the non-AP MLD determines whether the SMD to which each neighboring AP MLD belongs is the same as the SMD to which the current AP MLD of the non-AP MLD belongs based on the third information of each neighboring AP MLD. Since the non-AP MLD does not need to regenerate or negotiate the pair of temporary keys when switching between two AP MLDs within the same SMD, it can prioritize selecting a neighboring AP MLD belonging to the same SMD as the target AP MLD to reduce the latency of the roaming handover process.

[0027] In one possible design, the method of the second aspect further includes: receiving fourth information for providing information about neighboring AP MLDs of the non-AP MLD; the fourth information includes at least one of a robust secure network sub-element, a robust secure network extension sub-element, a supported rate and basic service set member selector sub-element, or an extended supported rate and basic service set member selector sub-element.

[0028] Based on this possible design, non-AP MLDs can directly obtain relevant information about neighboring AP MLDs through the fourth information. Compared to non-AP MLDs obtaining neighboring AP MLD information by scanning neighboring AP MLDs over the air interface, this reduces latency and improves roaming performance.

[0029] In one possible design, the first information is carried in any one of the beacon frame, probe request frame, neighbor report element, or newly defined SMD element; the newly defined SMD element is used to carry information related to the SMD to which the access point belongs.

[0030] Based on this possible design, various types of information are provided to carry the first information, thereby enhancing the diversity and flexibility of the first information transmission.

[0031] In one possible design, the second information is carried in any of the extended service set report element, the mobile domain element, or the newly defined SMD element.

[0032] Based on this possible design, various types of information are provided to carry the second information, thereby enhancing the diversity and flexibility of the second information transmission.

[0033] Thirdly, a communication method is provided. This method can be executed by the current AP MLD, or by components of the current AP MLD, such as the processor, chip, or chip system of the current AP MLD, or by a logic module or software capable of implementing all or part of the functions of the current AP MLD. The method includes: acquiring fifth information, which is used by the non-AP MLD to determine whether the clock of the current AP MLD is synchronized with the clock of the neighboring AP MLD; and sending the fifth information.

[0034] Based on the method described in the third aspect, the non-AP MLD can determine whether the clock of the current AP MLD is synchronized with the clock of the reported neighboring AP MLD based on the fifth information. The target AP MLD is one of the reported neighboring AP MLDs. Then, the non-AP MLD can determine whether the clock of the current AP MLD is synchronized with the clock of the target AP MLD based on the fifth information, determine whether the timestamp in the fast transfer probe response frame is accurate, and perform different operations based on the accuracy of the timestamp, so that the non-AP MLD and the target AP MLD can perform time synchronization related operations.

[0035] In one possible design, if the SMD to which the current AP MLD belongs is the same as the SMD to which the neighboring AP MLD belongs, the fifth information indicates that the clocks of each AP MLD in the SMD to which the current AP MLD belongs are synchronized.

[0036] Based on this possible design, when the SMD of the current AP MLD and the SMD of the neighboring AP MLD are the same, the non-AP MLD can indirectly determine that the clock of the current AP MLD is synchronized with the clock of the target AP MLD based on the fifth information.

[0037] In one possible design, the fifth piece of information indicates whether the clock of the current AP MLD is synchronized with the clock of the neighboring AP MLD.

[0038] Based on this possible design, the non-AP MLD can directly determine that the clock of the current AP MLD is synchronized with the clock of the target AP MLD based on the fifth information of the target AP MLD in the fifth information.

[0039] Fourthly, a communication method is provided. This method can be executed by a non-AP MLD, or by components of the non-AP MLD, such as a processor, chip, or chip system of the non-AP MLD, or by a logic module or software capable of implementing all or part of the functions of the non-AP MLD. The method includes: receiving fifth information, which is used by the non-AP MLD to determine whether the clock of the current AP MLD is synchronized with the clock of the neighboring AP MLD.

[0040] Based on the method described in the fourth aspect, the non-AP MLD can determine whether the clock of the current AP MLD is synchronized with the clock of the reported neighboring AP MLD based on the fifth information. The target AP MLD is one of the reported neighboring AP MLDs. Therefore, the non-AP MLD can determine whether the clock of the current AP MLD is synchronized with the clock of the target AP MLD based on the fifth information, determine whether the timestamp in the fast transfer probe response frame is accurate, and perform different operations based on the accuracy of the timestamp so that the non-AP MLD and the target AP MLD can perform time synchronization related operations.

[0041] In one possible design, if the SMD to which the current AP MLD belongs is the same as the SMD to which the neighboring AP MLD belongs, the fifth information indicates that the clocks of each AP MLD in the SMD to which the current AP MLD belongs are synchronized.

[0042] Based on this possible design, when the SMD of the current AP MLD and the SMD of the neighboring AP MLD are the same, the non-AP MLD can indirectly determine that the clock of the current AP MLD is synchronized with the clock of the target AP MLD based on the fifth information.

[0043] In one possible design, the fifth piece of information indicates whether the clock of the current AP MLD is synchronized with the clock of the neighboring AP MLD.

[0044] Based on this possible design, the non-AP MLD can directly determine that the clock of the current AP MLD is synchronized with the clock of the target AP MLD based on the fifth information of the target AP MLD in the fifth information.

[0045] Fifthly, a communication method is provided. This method can be executed by the current AP MLD, or by components of the current AP MLD, such as the processor, chip, or chip system of the current AP MLD, or by a logic module or software capable of implementing all or part of the functions of the current AP MLD. The method includes: obtaining sixth information, which is used by the non-AP MLD to determine whether a new Internet Protocol (IP) address needs to be requested when roaming from the current AP MLD to the target AP MLD; and sending the sixth information and a seventh information based on the sixth information. The seventh information is used by the non-AP MLD to determine whether data forwarding is supported between the current AP MLD and the target AP MLD.

[0046] Based on the method described in the fifth aspect, the non-AP MLD can roam from the current AP MLD to the target AP MLD without requesting a new IP address when it is determined based on the sixth information. When it is determined based on the seventh information that data forwarding is supported between the current AP MLD and the target AP MLD, the non-AP MLD will no longer request a new IP address from the server again, and will use the original IP address for data forwarding, thereby reducing the latency of data forwarding and roaming.

[0047] In one possible design, when a non-AP MLD roams between two AP MLDs in the same SMD while its IP address remains unchanged, the sixth piece of information indicates whether the SMD to which the current AP MLD belongs and the SMD to which the target AP MLD belongs are the same.

[0048] Based on this possible design, when a non-AP MLD roams between two AP MLDs in the same SMD, the IP address remains unchanged. This allows the non-AP MLD to determine, based on the sixth information, whether the SMD to which the current AP MLD belongs is the same as the SMD to which the target AP MLD belongs, and thus determine whether a new IP address needs to be requested when roaming from the current AP MLD to the target AP MLD.

[0049] In one possible design, the sixth piece of information indicates whether a non-AP MLD needs to request a new IP address when roaming from the current AP MLD to the target AP MLD.

[0050] Based on this possible design, the non-AP MLD can directly determine whether a new IP address needs to be requested when roaming from the current AP MLD to the target AP MLD based on the sixth information.

[0051] In one possible design, if the sixth information indicates that the non-AP MLD does not need to request a new IP address when roaming from the current AP MLD to the target AP MLD, the seventh information indicates that data forwarding is supported between the current AP MLD and the target AP MLD;

[0052] In cases where the sixth message indicates that a non-AP MLD needs to request a new IP address when roaming from the current AP MLD to the target AP MLD, the seventh message indicates that data forwarding is not supported between the current AP MLD and the target AP MLD.

[0053] Based on this possible design, when the sixth message indicates that a new IP address does not need to be requested when roaming from the current AP MLD to the target AP MLD, and the seventh message indicates that data fronthaul is supported between the current AP MLD and the target AP MLD, the non-AP MLD will not request a new IP address from the server again, but will use the original IP address for data fronthaul, reducing data fronthaul latency and roaming latency. Conversely, if the sixth message indicates that a new IP address needs to be requested when roaming from the current AP MLD to the target AP MLD, and the seventh message indicates that data fronthaul is not supported between the current AP MLD and the target AP MLD, data fronthaul will not be performed, reducing the roaming process duration.

[0054] In one possible design, when a non-AP MLD roams between two AP MLDs in the same SMD, and data forwarding is supported between the current AP MLD and the target AP MLD, the seventh information indicates whether the SMD to which the current AP MLD belongs and the SMD to which the target AP MLD belongs are the same.

[0055] Based on this possible design, when a non-AP MLD roams between two AP MLDs in the same SMD, and the current AP MLD and the target AP MLD support data forwarding, the non-AP MLD can determine whether the SMD to which the current AP MLD belongs and the SMD to which the target AP MLD belong are the same based on the seventh information, and thus determine whether the current AP MLD and the target AP MLD support data forwarding.

[0056] In one possible design, the seventh piece of information indicates whether data forwarding is supported between the current AP MLD and the target AP MLD.

[0057] Based on this possible design, the non-AP MLD can directly determine whether data forwarding is supported between the current AP MLD and the target AP MLD based on the seventh information.

[0058] In one possible design, the sixth and seventh information are carried in the same information, or the sixth and seventh information are carried in different information.

[0059] Based on this possible design, the sixth and seventh information can be carried in the same information to save signaling overhead; or, the sixth and seventh information can be carried in different information for flexible transmission.

[0060] Sixthly, a communication method is provided, which can be executed by a non-AP MLD, or by components of the non-AP MLD, such as a processor, chip, or chip system of the non-AP MLD, or by a logic module or software capable of implementing all or part of the functions of the non-AP MLD. The method includes receiving sixth information and seventh information. The sixth information is used by the non-AP MLD to determine whether a new Internet Protocol (IP) address needs to be requested when roaming from the current AP MLD to the target AP MLD; the seventh information is used by the non-AP MLD to determine whether data forwarding is supported between the current AP MLD and the target AP MLD.

[0061] Based on the method described in the sixth aspect, when the non-AP MLD roams from the current AP MLD to the target AP MLD based on the sixth information, it does not need to request a new IP address. When it is determined based on the seventh information that data forwarding is supported between the current AP MLD and the target AP MLD, it will no longer request a new IP address from the server again, but will use the original IP address for data forwarding, thereby reducing the latency of data forwarding and roaming.

[0062] In one possible design, when a non-AP MLD roams between two AP MLDs in the same SMD while its IP address remains unchanged, the sixth piece of information indicates whether the SMD to which the current AP MLD belongs and the SMD to which the target AP MLD belongs are the same.

[0063] Based on this possible design, when a non-AP MLD roams between two AP MLDs in the same SMD with the IP address remaining unchanged, the non-AP MLD can determine whether the SMD to which the current AP MLD belongs and the SMD to which the target AP MLD belongs are the same based on the sixth information, and thus determine whether a new IP address needs to be requested when roaming from the current AP MLD to the target AP MLD.

[0064] In one possible design, the sixth piece of information indicates whether a non-AP MLD needs to request a new IP address when roaming from the current AP MLD to the target AP MLD.

[0065] Based on this possible design, a non-AP MLD can directly determine whether a new IP address needs to be requested when roaming from the current AP MLD to the target AP MLD based on the sixth information.

[0066] In one possible design, the seventh message includes either an indication that data fronthaul is supported between the current AP MLD and the target AP MLD, or that data fronthaul is not supported between the current AP MLD and the target AP MLD.

[0067] Based on this possible design, the non-AP MLD can directly determine whether data forwarding is supported between the current AP MLD and the target AP MLD based on the content of the seventh information.

[0068] In one possible design, when a non-AP MLD roams between two AP MLDs in the same SMD, and data forwarding is supported between the current AP MLD and the target AP MLD, the seventh information indicates whether the SMD to which the current AP MLD belongs and the SMD to which the target AP MLD belongs are the same.

[0069] Based on this possible design, when a non-AP MLD roams between two AP MLDs in the same SMD, and the current AP MLD and the target AP MLD support data forwarding, the non-AP MLD can determine whether the SMD to which the current AP MLD belongs and the SMD to which the target AP MLD belong are the same based on the seventh information, and thus determine whether the current AP MLD and the target AP MLD support data forwarding.

[0070] In one possible design, the seventh piece of information indicates whether data fronthaul is supported between the current AP MLD and the target AP MLD. Based on this possible design, the non-AP MLD can directly determine whether data fronthaul is supported between the current AP MLD and the target AP MLD based on the seventh piece of information.

[0071] In one possible design, the sixth and seventh information are carried in the same information, or the sixth and seventh information are carried in different information.

[0072] Based on this possible design, the sixth and seventh information can be carried in the same information to save signaling overhead; or, the sixth and seventh information can be carried in different information for flexible transmission.

[0073] In a seventh aspect, a communication method is provided. This method can be executed by the current AP MLD, or by components of the current AP MLD, such as the processor, chip, or chip system of the current AP MLD, or by a logic module or software capable of implementing all or part of the functions of the current AP MLD. The method includes: acquiring eighth information and ninth information, wherein the eighth information indicates whether to request data forwarding, and the ninth information indicates whether to request context transfer; and sending the eighth information and the ninth information. Wherein, if the eighth information indicates that data forwarding is enabled, the ninth information indicates that context transfer is enabled.

[0074] Based on the method described in the seventh aspect, the non-AP MLD enables context transfer when the eighth information indicates that data fronthaul should be enabled. This avoids the problem of the non-AP MLD still performing context transfer even when the eighth information indicates that the current AP MLD should not enable (or disable) data fronthaul, thus preventing the waste of air interface resources during roaming.

[0075] In one possible design, if the eighth message indicates that data forwarding is disabled, the ninth message indicates that context transfer is disabled.

[0076] Based on this possible design, the context transfer enabled state indicated by the ninth information is the same as the data forwarding enabled state indicated by the eighth information. This avoids the problem that the non-AP MLD will still perform a context transfer even when the eighth information indicates that the current AP MLD is not enabled (or is disabled).

[0077] In one possible design, the eighth and ninth information are carried in the same information, or the eighth and ninth information are carried in different information.

[0078] Based on this possible design, the eighth and ninth information can be carried in the same information to save signaling overhead; or, the eighth and ninth information can be carried in different information for flexible transmission.

[0079] Eighthly, a communication method is provided, which can be executed by a non-AP MLD, or by a component of the non-AP MLD, such as a processor, chip, or chip system of the non-AP MLD, or by a logic module or software capable of implementing all or part of the functions of the non-AP MLD. The method includes: receiving eighth information and ninth information. The eighth information is used to indicate whether data forwarding is requested, and the ninth information is used to indicate whether context transfer is requested; sending the eighth information and the ninth information. Wherein, if the eighth information indicates that data forwarding is initiated, the ninth information indicates that context transfer is initiated.

[0080] Based on the method described in the eighth aspect, the non-AP MLD initiates context transfer when the eighth information indicates that data fronthaul is enabled. This avoids the problem of the non-AP MLD still performing context transfer even when the eighth information indicates that the current AP MLD is not enabling (or disabling) data fronthaul, thus preventing the waste of air interface resources during roaming.

[0081] In one possible design, if the eighth message indicates that data forwarding is disabled, the ninth message indicates that context transfer is disabled.

[0082] Based on this possible design, the context transfer enabled state indicated by the ninth information is the same as the data forwarding enabled state indicated by the eighth information. This avoids the problem that the non-AP MLD will still perform a context transfer even when the eighth information indicates that the current AP MLD is not enabled (or is disabled).

[0083] In one possible design, the eighth and ninth information are carried in the same information, or the eighth and ninth information are carried in different information.

[0084] Based on this possible design, the eighth and ninth information can be carried in the same information to save signaling overhead; or, the eighth and ninth information can be carried in different information for flexible transmission.

[0085] Ninthly, a communication method is provided. This method can be executed by a target AP MLD, or by a component of the target AP MLD, such as a processor, chip, or chip system of the target AP MLD, or by a logic module or software capable of implementing all or part of the functions of the target AP MLD. The method includes: obtaining a first service start time; and, upon the arrival of the first service start time, initiating scheduling of the non-AP MLD. The first service start time is obtained by calibrating a second service start time using the timing synchronization function (TSF) offset (TSF_offset) between the current AP MLD and the target AP MLD. The second service start time is the service start time negotiated when the non-AP MLD and the current AP MLD establish a stream classification service (SCS) session.

[0086] Based on the method described in the ninth aspect, compared to the target AP MLD scheduling non-AP MLD start time / time obtained from the roaming request frame transmission time, the target AP MLD scheduling non-AP MLD start time / time is obtained after calibrating the second service start time using the TSF_offset between the current AP MLD and the target AP MLD. This makes the target AP MLD scheduling non-AP MLD start time / time no longer change with the roaming request frame transmission time, reducing the complexity of the target AP MLD in determining the scheduling non-AP MLD start time / time.

[0087] In one possible design, obtaining the first service start time includes: obtaining the first service start time and obtaining the reference link identifier of the target AP MLD.

[0088] Based on this possible design, when the first service start time arrives, the target AP MLD can schedule the non-AP MLD in the link corresponding to the reference link identifier of the target AP MLD to ensure the reliability of the scheduling.

[0089] In one possible design, obtaining the first service start time includes: receiving a second service start time and the TSF value of the reference link corresponding to the current AP MLD; and obtaining the first service start time based on the second service start time and the TSF value of the reference link corresponding to the current AP MLD. The reference link is the link corresponding to the service start time link identifier negotiated when the non-AP MLD and the current AP MLD establish an SCS session.

[0090] Based on this possible design, the target AP MLD can indirectly obtain the first service start time by using the second service start time and the TSF value of the reference link corresponding to the current AP MLD, which increases the flexibility of the target AP MLD in obtaining the first service start time.

[0091] In one possible design, the first service start time is obtained by calibrating the second service start time using the TSF_offset between the current AP MLD and the target AP MLD. This includes: the first service start time is obtained by adding the second service start time to the TSF_offset between the current AP MLD and the target AP MLD.

[0092] Based on this possible design, the sum of the TSF_offset between the current AP MLD and the target AP MLD and the second service start time can be used as the first service start time. This allows us to obtain the first service start time.

[0093] In one possible design, the TSF_offset between the current AP MLD and the target AP MLD is obtained by subtracting the TSF value of the reference link corresponding to the current AP MLD from the TSF value of the reference link corresponding to the target AP MLD.

[0094] Based on this possible design, the difference between the TSF value of the reference link corresponding to the target AP MLD and the TSF value of the reference link corresponding to the current AP MLD can be used as the TSF_offset between the current AP MLD and the target AP MLD; then, the TSF_offset can be used to calibrate the second service start time to obtain the first service start time.

[0095] In a tenth aspect, a communication method is provided, which can be executed by a neighboring AP MLD, or by a component of the neighboring AP MLD, such as a processor, chip, or chip system of the neighboring AP MLD, or by a logic module or software capable of implementing all or part of the functions of the neighboring AP MLD. The method includes: receiving a null data packet announcement (NDPA) and a twelfth message from the non-AP MLD; and in response to the NDPA, sending a null data packet (NDP) and the NDPA to the non-AP MLD according to the twelfth message, or sending the NDP. The twelfth message is used to instruct the neighboring AP MLD to send the NDP after receiving the NDPA, or to send both the NDPA and the NDP.

[0096] Based on the method described in the tenth aspect, when the non-AP MLD knows the transmission power of the neighboring AP MLD and maintains time synchronization between the neighboring AP MLD and the current AP MLD, or knows the TSF_offset between the neighboring AP MLD and the current AP MLD, the non-AP MLD sends the twelfth message instructing the neighboring AP MLD to send NDP after receiving NDPA, so that the neighboring AP MLD no longer sends NDPA after responding to NDPA, thereby improving the utilization rate of air interface resources.

[0097] In one possible design, the twelfth message instructs the neighboring AP MLD to send an NDP upon receiving an NDPA, or to send both an NDPA and an NDP. Based on this possible design, the twelfth message directly instructs the neighboring AP MLD to send an NDP upon receiving an NDPA, or to send both an NDPA and an NDP, thus saving signaling overhead.

[0098] In one possible design, if the twelfth message instructs the neighboring AP MLD to send an NDP after receiving an NDPA, or to send both an NDPA and an NDP, the twelfth message is carried in the required NDPA field, which is a field in the newly defined NDPA.

[0099] Based on this possible design, a new NDPA format for carrying the twelfth information is provided, enabling the twelfth information to be carried in NDPA conforming to wireless communication protocol standards.

[0100] In one possible design, the twelfth message instructs the neighboring AP MLD whether to send its own TSF and whether to send its own transmission power after receiving the NDPA; if the twelfth message instructs the neighboring AP MLD not to send its own TSF and not to send its own transmission power after receiving the NDPA, the neighboring AP MLD sends the NDP after receiving the NDPA.

[0101] Based on this possible design, by instructing the neighboring AP MLD whether to send its own TSF after receiving NDPA, and whether to send its own transmission power, the diversity of the twelfth information indication is indirectly increased.

[0102] In one possible design, if the twelfth message instructs the neighboring AP MLD whether to send its own TSF and whether to send its own transmission power after receiving the NDPA, the twelfth message can be carried in the required transmission power (TX power required) field and the required TSF (TSF required) field; the required transmission power field and the required TSF field are fields in the newly defined NDPA.

[0103] Based on this possible design, a new NDPA format for carrying the twelfth information is provided, enabling the twelfth information to be carried in an NDPA that conforms to wireless communication protocol standards.

[0104] Eleventhly, this application provides a communication device, which can be an AP MLD or a chip or system-on-a-chip within the AP MLD, or a functional module within the AP MLD for implementing the methods in the first aspect or any possible design of the first aspect. This communication device can implement the functions performed by the AP MLD in the first aspect or any possible design of the first aspect, and these functions can be implemented by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the aforementioned functions. For example, the communication device may include a processing unit and a transceiver unit.

[0105] The processing unit is used to acquire the first information.

[0106] The transceiver unit is used to send the first information; the first information is used to indicate the type of SMD to which the AP MLD belongs, and the type of SMD is either a centralized SMD or a distributed SMD.

[0107] Specifically, the execution actions of each unit of the communication device can be referred to in the first aspect or any possible design of the first aspect, and will not be repeated here.

[0108] In a twelfth aspect, this application provides a communication device, which can be a non-AP MLD or a chip or system-on-a-chip within a non-AP MLD, and can also be a functional module within a non-AP MLD for implementing the methods of the second aspect or any possible design of the second aspect. This communication device can implement the functions performed by the non-AP MLD in the aforementioned second aspect or possible designs of the second aspect, and these functions can be implemented by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the aforementioned functions. For example, the communication device may include a receiving unit and a processing unit.

[0109] The transceiver unit is used to receive the first information; the first information is used to indicate the type of SMD to which the AP MLD belongs, and the type of SMD is either a centralized SMD or a distributed SMD.

[0110] The processing unit is used to execute the roaming process corresponding to the first information of the current access point and the type of SMD indicated in the first information.

[0111] Specifically, the execution actions of each unit of the communication device can be referred to in the second aspect or any possible design of the second aspect, and will not be repeated here.

[0112] In a thirteenth aspect, this application provides a communication device, which can be a current AP MLD or a chip or system-on-a-chip within the current AP MLD, and can also be a functional module within the current AP MLD for implementing the methods of the third aspect or any possible design of the third aspect. This communication device can implement the functions performed by the current AP MLD in the aforementioned third aspect or possible designs of the third aspect, and these functions can be implemented by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the aforementioned functions. For example, the communication device may include a processing unit and a transceiver unit.

[0113] The processing unit is used to acquire the fifth information, which is used by the non-AP MLD to determine whether the clock of the current AP MLD is synchronized with the clock of the neighboring AP MLD.

[0114] The transceiver unit is used to send the fifth message.

[0115] Specifically, the execution actions of each unit of the communication device can be referred to in the third aspect or any possible design of the third aspect, and will not be elaborated further.

[0116] In a fourteenth aspect, this application provides a communication device, which can be a non-AP MLD or a chip or system-on-a-chip within a non-AP MLD, and can also be a functional module within a non-AP MLD for implementing the methods of the fourth aspect or any possible design of the fourth aspect. This communication device can implement the functions performed by the non-access point multi-link device in the aforementioned fourth aspect or possible designs of the fourth aspect, and these functions can be implemented by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the aforementioned functions. For example, the communication device may include a receiving unit.

[0117] The transceiver unit is used to receive the fifth information, which is used by the non-AP MLD to determine whether the clock of the current AP MLD is synchronized with the clock of the neighboring AP MLD.

[0118] Specifically, the execution actions of each unit of the communication device can be referred to in the fourth aspect or any possible design of the fourth aspect, and will not be repeated here.

[0119] In a fifteenth aspect, this application provides a communication device, which can be a current AP MLD or a chip or system-on-a-chip within the current AP MLD, and can also be a functional module within the current AP MLD for implementing the methods in the fifth aspect or any possible design of the fifth aspect. This communication device can implement the functions performed by the current AP MLD in the aforementioned fifth aspect or possible designs of the fifth aspect, and these functions can be implemented by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the aforementioned functions. For example, the communication device may include a processing unit and a transceiver unit.

[0120] The processing unit is used to obtain the sixth information, which is used by the non-AP MLD to determine whether a new Internet Protocol (IP) address needs to be requested when roaming from the current AP MLD to the target AP MLD.

[0121] The transceiver unit is used to send the sixth and seventh information according to the sixth information; the seventh information is used by the non-AP MLD to determine whether data fronthaul is supported between the current AP MLD and the target AP MLD.

[0122] Specifically, the execution actions of each unit of the communication device can be referred to in the fifth aspect or any possible design of the fifth aspect, and will not be repeated here.

[0123] In a sixteenth aspect, this application provides a communication device, which can be a non-AP MLD or a chip or system-on-a-chip within a non-AP MLD, and can also be a functional module within a non-AP MLD for implementing the methods in the sixth aspect or any possible design of the sixth aspect. This communication device can implement the functions performed by the non-AP MLD in the sixth aspect or any possible design of the sixth aspect, and these functions can be implemented by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the aforementioned functions. For example, the communication device may include a receiving unit.

[0124] The transceiver unit is used to receive the sixth and seventh information. The sixth information is used by the non-AP MLD to determine whether the clock of the current AP MLD is synchronized with the clock of the neighboring AP MLD. The seventh information is used by the non-AP MLD to determine whether data forwarding is supported between the current AP MLD and the target AP MLD.

[0125] Specifically, the execution actions of each unit of the communication device can be referred to in the sixth aspect or any possible design of the sixth aspect, and will not be repeated here.

[0126] In a seventeenth aspect, this application provides a communication device, which can be a current AP MLD or a chip or system-on-a-chip within the current AP MLD, and can also be a functional module within the current AP MLD for implementing the methods in the seventh aspect or any possible design of the seventh aspect. This communication device can implement the functions performed by the current AP MLD in the aforementioned seventh aspect or possible designs of the seventh aspect, and these functions can be implemented by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the aforementioned functions. For example, the communication device may include a processing unit and a transceiver unit.

[0127] The processing unit is used to acquire eighth information and ninth information. The eighth information is used to indicate whether to request data forwarding, and the ninth information is used to indicate whether to request context transfer. When the eighth information indicates that data forwarding is enabled, the ninth information indicates that context transfer is enabled.

[0128] The transceiver unit is used to send the eighth or ninth message.

[0129] Specifically, the execution actions of each unit of the communication device can be referred to in the seventh aspect or any possible design of the seventh aspect, and will not be repeated here.

[0130] In an eighteenth aspect, this application provides a communication device, which can be a non-AP MLD or a chip or system-on-a-chip within a non-AP MLD, and can also be a functional module within a non-AP MLD for implementing the methods of the eighth aspect or any possible design of the eighth aspect. This communication device can implement the functions performed by the non-AP MLD in the aforementioned eighth aspect or possible designs of the eighth aspect, and these functions can be implemented by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the aforementioned functions. For example, the communication device may include a receiving unit.

[0131] The transceiver unit is used to receive the eighth information and the ninth information. The eighth information is used to indicate whether to request data forwarding, and the ninth information is used to indicate whether to request context transfer. In the case that the eighth information indicates to enable data forwarding, the ninth information indicates to enable context transfer.

[0132] Specifically, the execution actions of each unit of the communication device can be referred to in the eighth aspect or any possible design of the eighth aspect, and will not be repeated here.

[0133] In a nineteenth aspect, this application provides a communication device, which can be a target AP MLD or a chip or system-on-a-chip within the target AP MLD, and can also be a functional module within the target AP MLD for implementing the methods in the ninth aspect or any possible design of the ninth aspect. This communication device can implement the functions performed by the target AP MLD in the ninth aspect or any possible design of the ninth aspect, and these functions can be implemented by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the aforementioned functions. For example, the communication device may include a processing unit and a transceiver unit.

[0134] The processing unit is used to obtain the first service start time; the first service start time is obtained by calibrating the second service start time after the TSF_offset between the current AP MLD and the target AP MLD is calibrated; the second service start time is the service start time negotiated when the non-AP MLD and the current AP MLD establish an SCS session.

[0135] The transceiver unit is used to start scheduling non-AP MLD when the first service start time arrives.

[0136] Specifically, the execution actions of each unit of the communication device can be referred to in the ninth aspect or any possible design of the ninth aspect, and will not be repeated here.

[0137] In a twentieth aspect, this application provides a communication device, which can be a neighboring AP MLD or a chip or system-on-a-chip within the neighboring AP MLD, and can also be a functional module within the neighboring AP MLD for implementing the methods in the tenth aspect or any possible design of the tenth aspect. This communication device can implement the functions performed by the neighboring AP MLD in the aforementioned tenth aspect or possible design of the tenth aspect, and these functions can be implemented by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the aforementioned functions. For example, the communication device may include a processing unit and a transceiver unit.

[0138] The transceiver unit is used to receive NDPA and the twelfth message. The twelfth message is used to instruct the neighboring AP MLD to send NDP after receiving NDPA, or to send NDPA and NDP.

[0139] The processing unit is used to respond to NDPA by sending NDP and NDPA to the non-AP MLD according to the twelfth information, or by sending NDP.

[0140] Specifically, the execution actions of each unit of the communication device can be referred to in the tenth aspect or any possible design of the tenth aspect, and will not be repeated here.

[0141] In a twentieth aspect, this application provides a communication device, which can be the aforementioned AP MLD (e.g., current AP MLD, neighboring AP MLD, target AP MLD) or non-AP MLD. In one possible design, the communication device includes a processor. The processor is configured to support the communication device in executing the communication methods described in any of the above aspects or any of the possible designs. In yet another possible design, the communication device may further include a memory for storing instructions and / or data. When the communication device is running, the processor executes the computer execution instructions stored in the memory to cause the communication device to perform the communication methods described in any of the above aspects or any of the possible designs.

[0142] In a twentieth aspect, this application provides a communication system comprising an AP MLD (e.g., a current AP MLD, a neighboring AP MLD, and a target AP MLD) and a non-AP MLD. The AP MLD is used to implement the method described in the first aspect and any possible design thereof, and the non-AP MLD is used to implement the method described in the second aspect and any possible design thereof; or, the current AP MLD is used to implement the method described in the third aspect and any possible design thereof, and the non-AP MLD is used to implement the method described in the fourth aspect and any possible design thereof; or, the current AP MLD is used to implement the method described in the fifth aspect and any possible design thereof, and the non-AP MLD is used to implement the method described in the sixth aspect and any possible design thereof; or, the current AP MLD is used to implement the method described in the seventh aspect and any possible design thereof, and the non-AP MLD is used to implement the method described in the eighth aspect and any possible design thereof; or, the target AP MLD is used to implement the method described in the ninth aspect and any possible design thereof, and the non-AP MLD is used to implement the method described in the ninth aspect and any possible design thereof; or, the neighboring AP MLD is used to implement the method described in the tenth aspect and any possible design thereof, and the non-AP MLD is used to implement the method described in the tenth aspect and any possible design thereof.

[0143] In a twentieth aspect, this application provides a computer-readable storage medium storing computer instructions that, when executed on a computer, cause the computer to perform the communication method of the first aspect or any possible design of the first aspect; or, cause the computer to perform the communication method of the second aspect or any possible design of the second aspect; or, cause the computer to perform the communication method of the third aspect or any possible design of the third aspect; or, cause the computer to perform the communication method of the fourth aspect or any possible design of the fourth aspect; or, cause the computer to perform the communication method of the fifth aspect or any possible design of the fifth aspect; or, cause the computer to perform the communication method of the sixth aspect or any possible design of the sixth aspect; or, cause the computer to perform the communication method of the seventh aspect or any possible design of the seventh aspect; or, cause the computer to perform the communication method of the eighth aspect or any possible design of the eighth aspect; or, cause the computer to perform the communication method of the ninth aspect or any possible design of the ninth aspect; or, cause the computer to perform the communication method of the tenth aspect or any possible design of the tenth aspect.

[0144] In a twentieth aspect, this application provides a computer program product comprising computer instructions that, when executed on a computer, cause the computer to perform the communication method of the first aspect or any possible design of the first aspect; or cause the computer to perform the communication method of the second aspect or any possible design of the second aspect; or cause the computer to perform the communication method of the third aspect or any possible design of the third aspect; or cause the computer to perform the communication method of the fourth aspect or any possible design of the fourth aspect; or cause the computer to perform the communication method of the fifth aspect or any possible design of the fifth aspect; or cause the computer to perform the communication method of the sixth aspect or any possible design of the sixth aspect; or cause the computer to perform the communication method of the seventh aspect or any possible design of the seventh aspect; or cause the computer to perform the communication method of the eighth aspect or any possible design of the eighth aspect; or cause the computer to perform the communication method of the ninth aspect or any possible design of the ninth aspect; or cause the computer to perform the communication method of the tenth aspect or any possible design of the tenth aspect. Attached Figure Description

[0145] Figure 1 is a schematic diagram of the interaction between AP MLD and non-AP MLD provided in an embodiment of this application;

[0146] Figure 2 is a schematic diagram of a roaming process for a central SMD provided in an embodiment of this application;

[0147] Figure 3 is a schematic diagram of a distributed SMD roaming process provided in an embodiment of this application;

[0148] Figure 4 is a schematic diagram of a fast BSS switching roaming process provided in an embodiment of this application;

[0149] Figure 5 is a schematic diagram of the architecture of a communication system provided in an embodiment of this application;

[0150] Figure 6 is a schematic diagram of the architecture of a communication system in a roaming scenario provided in an embodiment of this application;

[0151] Figure 7 is a flowchart illustrating a communication method provided in an embodiment of this application;

[0152] Figure 8 is a schematic diagram of the format of a neighbor report element provided in an embodiment of this application;

[0153] Figure 9 is a schematic diagram of the format of an ESS report element provided in an embodiment of this application;

[0154] Figure 10 is a schematic diagram of the format of an ESS information field provided in an embodiment of this application;

[0155] Figure 11 is a flowchart illustrating another communication method provided in an embodiment of this application;

[0156] Figure 12 is a flowchart illustrating another communication method provided in an embodiment of this application;

[0157] Figure 13 is a flowchart illustrating another communication method provided in an embodiment of this application;

[0158] Figure 14 is a schematic diagram of the frame format of an SCS request frame provided in an embodiment of this application;

[0159] Figure 15 is a schematic diagram of the format of an SCS descriptor provided in an embodiment of this application;

[0160] Figure 16 is a schematic diagram of the format of a priority element within an access category provided in an embodiment of this application;

[0161] Figure 17 is a schematic diagram of the frame format of an SCS response frame provided in an embodiment of this application;

[0162] Figure 18 is a flowchart illustrating another communication method provided in an embodiment of this application;

[0163] Figure 19 is a flowchart illustrating another communication method provided in an embodiment of this application;

[0164] Figure 20 is a schematic diagram of a communication device provided in an embodiment of this application;

[0165] Figure 21 is a schematic diagram of another communication device provided in an embodiment of this application;

[0166] Figure 22 is a schematic diagram of the structure of another communication device provided in an embodiment of this application. Detailed Implementation

[0167] Before introducing the embodiments of this application, some technical terms involved in the embodiments of this application will be explained. It should be noted that the following explanations are for the purpose of making the embodiments of this application easier to understand, and should not be regarded as a limitation on the scope of protection claimed by the embodiments of this application.

[0168] 1. Multi-link device (MLD)

[0169] MLD refers to a device capable of communicating through multiple wireless links. Any two of these links support simultaneous transmission and reception (STL, Rx, STR), meaning that while one link is sending information, the other is receiving information.

[0170] MLDs can be divided into AP MLDs and non-AP MLDs based on device type. Non-AP MLDs can also refer to non-access point STA multi-link devices (non-AP STA MLDs).

[0171] Optionally, a Medium Access Control (MAC) address can be used to uniquely identify an MLD. An MLD can include one or more subsidiary nodes, and these subsidiary nodes can have different MAC addresses. Specifically, the number of subsidiary nodes included in an MLD varies depending on the device type.

[0172] For example, an AP MLD can include one or more affiliated APs, which are integrated into or installed in the multi-link device lower MAC sublayer of the AP MLD, with each affiliated AP operating on a different link. Similarly, a non-AP MLD can include one or more affiliated non-AP STAs, each operating on a different link. If a non-AP MLD comprises multiple affiliated non-AP MLDs, which are integrated into or installed in the MLD lower MAC sublayer of the non-AP MLD, and the channel spacing between the different affiliated non-AP MLDs is sufficiently large, then the multiple affiliated non-AP MLDs can operate independently without interfering with each other.

[0173] The MAC layer of MLD can be divided into the MLD upper MAC sublayer and the MLD lower MAC sublayer.

[0174] AP MLDs can be divided into collocated AP MLDs and non-collocated AP MLDs (NC AP MLDs). In a collocated AP MLD, both the MLD upper MAC sublayer and the MLD lower MAC sublayer are deployed in a single physical entity, and the multiple auxiliary APs included in a collocated AP MLD are located on the same physical entity or even a single chip. In an NC AP MLD, the MLD upper MAC sublayer and the MLD lower MAC sublayer are deployed in different physical entities, and the MLD upper MAC sublayer and the MLD lower MAC sublayer communicate with each other via a wired interface.

[0175] Figure 1 illustrates the interaction between AP MLD and non-AP MLD. In Figure 1, AP MLD includes three auxiliary APs: Auxiliary Access Point 1 (Auxiliary AP1), Auxiliary Access Point 2 (Auxiliary AP2), and Auxiliary Access Point 3 (Auxiliary AP3). Non-AP MLD includes three auxiliary STAs: Auxiliary Site 1 (Auxiliary STA1), Auxiliary Site 2 (Auxiliary STA2), and Auxiliary Site 3 (Auxiliary STA3). As shown in Figure 1, at the same time, Auxiliary STA1 of non-AP MLD can transmit data with Auxiliary AP1 of AP MLD1 via the first link; Auxiliary STA2 of non-AP MLD can transmit data with Auxiliary AP2 of AP MLD2 via the second link; and Auxiliary STA3 of non-AP MLD can transmit data with Auxiliary AP3 of AP MLD2 via the third link.

[0176] 2. Roaming

[0177] Roaming refers to the ability of a wireless terminal, such as a non-AP MLD, to switch from the current AP MLD to an AP MLD with better signal quality or service, such as a target AP MLD, when moving within a network covered by multiple AP MLDs, without interrupting network connectivity or affecting application operation.

[0178] In this application, "current AP MLD" refers to the AP MLD currently providing service to the non-AP MLD. "Target AP MLD" refers to the AP MLD that will take over the service from the current AP MLD to the non-AP MLD. AP MLD can be abbreviated as AP, and non-AP MLD can be abbreviated as non-AP or STA.

[0179] Currently, a low-latency roaming technology has been proposed: seamless roaming. Seamless roaming refers to the ability of a non-AP MLD to quickly and freely switch from the current AP MLD to the target AP MLD while moving. Under seamless roaming, the switching time between AP MLDs for a non-AP MLD can be controlled in the millisecond range, with virtually no packet loss.

[0180] Seamless roaming processes are divided into two categories: roaming processes based on the Seamless Mobility Domain (SMD) and roaming processes based on the Basic Service Set (BSS) handover. SMD-based roaming processes include centralized SMD roaming processes and distributed SMD roaming processes. Different seamless roaming processes have different characteristics.

[0181] (1) Roaming process of central SMD

[0182] The roaming process of a centralized SMD is the roaming process executed by non-AP MLDs and AP MLDs under the centralized SMD architecture. The centralized SMD architecture can consist of multiple NC AP MLDs and multiple non-AP MLDs. Each non-AP MLD can be connected to the distributed system (DS) through association with NC AP MLDs.

[0183] Figure 2 is a schematic diagram of the centralized SMD roaming process. As shown in Figure 2, the roaming process of the centralized SMD includes S201-S204.

[0184] S201: The non-AP MLD sends a probe request frame to the current AP MLD, and the current AP MLD receives the probe request frame.

[0185] The probe request frame is used to request information about the target AP MLD within the current AP MLD. The frame body format of the probe request frame is shown in Table 1 below.

[0186] Table 1. Frame body format of probe request frames.

[0187] Optionally, prior to step S201, both the non-AP MLD and the current AP MLD perform operations related to the 802.11K / V / R protocol. The relevant operations of the 802.11K / V / R protocol are described in existing technology and will not be repeated here.

[0188] S202: The current AP MLD sends a probe response frame to the non-AP MLD, and the non-AP MLD receives the probe response frame.

[0189] The probe response frame is used to respond to the probe request frame. The frame body format of the probe response frame is shown in Table 2 below.

[0190] Table 2. Frame body format of the probe response frame

[0191] S203: The non-AP MLD sends a link reconfiguration establishment request frame to the current AP MLD, and the current AP MLD receives the link reconfiguration establishment request frame.

[0192] The link reconfiguration setup request frame can be used to request the establishment of a link between a non-AP MLD and a target AP MLD, as well as to perform operations such as static context transfer and data forwarding.

[0193] Data fronthaul includes the current AP MLD forwarding any uncompleted downlink data to the target AP MLD, which then continues to send the uncompleted downlink data to the non-AP MLD; it may even include the target AP MLD forwarding uplink data received from the non-AP MLD to the current AP MLD, which then delivers the uplink data to its own logical link control (LLC) layer and DS layer in sequence.

[0194] The target AP MLD is the AP MLD that takes over the service of the non-AP MLD from the current AP MLD. That is, the non-AP MLD will roam from the current AP MLD to the target AP MLD.

[0195] S204: The current AP MLD sends a link reconfiguration establishment response frame to the non-AP MLD, and the non-AP MLD receives the link reconfiguration establishment response frame.

[0196] The link reconfiguration setup response frame is used to respond to the link reconfiguration setup request frame.

[0197] It should be understood that S201-S204 describes the air interface interaction process between the non-AP MLD and the current AP MLD. In addition, it may also involve the interaction between the current AP MLD and the target AP MLD. For details, please refer to the existing technology, which will not be elaborated here.

[0198] (2) Roaming process of distributed SMD

[0199] The roaming process of a distributed SMD is the roaming process executed by non-AP MLDs and AP MLDs under a distributed SMD architecture. A distributed SMD architecture can consist of multiple co-located AP MLDs and multiple non-AP MLDs. Each non-AP MLD can be connected to the DS through the MAC SAP associated with the AP MLD.

[0200] Figure 3 is a schematic diagram of the distributed SMD roaming process. As shown in Figure 3, the distributed SMD roaming process includes S301-S309.

[0201] S301: The non-AP MLD sends a probe request frame to the current AP MLD, and the current AP MLD receives the probe request frame.

[0202] S302: The current AP MLD sends a probe response frame to the non-AP MLD, and the non-AP MLD receives the probe response frame.

[0203] S303: The non-AP MLD sends a link reconfiguration establishment request frame to the current AP MLD, and the current AP MLD receives the link reconfiguration establishment request frame.

[0204] S304: The current AP MLD sends a link reconfiguration establishment response frame to the non-AP MLD, and the non-AP MLD receives the link reconfiguration establishment response frame.

[0205] S301-S304 are the same as S201-S204 above, and will not be repeated here.

[0206] S305: The non-AP MLD sends a roaming request frame to the target AP MLD, and the target AP MLD receives the roaming request frame.

[0207] The process of the non-AP MLD sending a roaming request frame to the target AP MLD includes: the non-AP MLD detecting the link signal quality between the non-AP MLD and the target AP MLD, and if the link signal quality reaches a preset threshold, the non-AP MLD sending a roaming request frame to the target AP MLD.

[0208] Among them, the romaning request frame is used to trigger the target AP MLD's dynamic context transfer, DS mapping switching, and possible data forwarding.

[0209] Dynamic context transfer is used for the interaction between the target AP MLD and the current AP MLD. Configuration information related to the non-AP MLD within the current AP MLD, such as block acknowledgment protocol information, is transferred. The target AP MLD performs dynamic context transfer via steps S306 and S308 below.

[0210] The DS mapping switch is used to update the packet forwarding path of the non-AP MLD in the DS. The target AP MLD performs the DS mapping switch via S307 below.

[0211] S306: The target AP MLD sends a context transfer request frame to the current AP MLD, and the current AP MLD receives the context transfer request frame.

[0212] S307: The target AP MLD sends a DS-STA notification request (DS-STA-notify.request) to the DS, and the DS receives the DS-STA notification request.

[0213] S308: The current AP MLD sends a context transfer response frame to the target AP MLD, and the target AP MLD receives the context transfer response frame.

[0214] S309: The target AP MLD sends a roaming response frame to the non-AP MLD, and the non-AP MLD receives the roaming response frame.

[0215] The romaning response frame is used to respond to the romancing request frame.

[0216] It should be understood that S301-S309 above describes the air interface interaction between the non-AP MLD and the current AP MLD. In addition, there may also be wired interaction between the current AP MLD and the target AP MLD. For details, please refer to the existing technology, which will not be elaborated here.

[0217] (3) Roaming process for fast BSS switching

[0218] The roaming process for fast BSS handover is the roaming process performed between non-AP MLDs under the fast BSS transition architecture. Similar to the distributed SMD architecture, the fast BSS transition architecture can consist of multiple co-located AP MLDs and multiple non-AP MLDs. Each non-AP MLD can access the DS through the MAC SAP associated with the AP MLD.

[0219] Figure 4 is a schematic diagram of the roaming process for fast BSS handover. As shown in Figure 4, the roaming process for fast BSS handover includes S401-S411.

[0220] S401: The non-AP MLD sends a fast transfer probe request frame to the current AP MLD, and the current AP MLD receives the fast transfer probe request frame.

[0221] The fast transition (FT) probe request frame functions similarly to the probe request frame, also used to request information about the target AP MLD within the current AP MLD. The difference between the fast transition probe request frame and the probe request frame lies in their frame format, as shown in Table 3 below.

[0222] Table 3. Frame format of fast transfer probe request frames.

[0223] In Table 3, the FT action is used to indicate that the fast transfer probe request frame is an FT action frame. The MAC address of the non-AP MLD is set to the MLD MAC address of the non-AP MLD, and the MAC address of the target AP MLD is set to the MLD MAC address of the target AP MLD. The format of the frame body is the same as the frame body format of the probe request frame in S201, and will not be described again here.

[0224] S402: The current AP MLD forwards the Fast Transfer Probe Request (FTP) frame to the target AP MLD via DS pass-through, and the target AP MLD receives the FTP frame.

[0225] Specifically, the current AP MLD sending a fast transfer probe request frame to the target AP MLD via DS transparent transmission (tunneled) means that the current AP MLD will receive the fast transfer probe request frame, encapsulate it after certain modifications, and then forward it to the target AP MLD. In other words, the fast transfer probe request frame forwarded by the current AP MLD may be a processed and encapsulated fast transfer probe request frame by the current AP MLD.

[0226] S403: The target AP MLD sends a fast transfer probe response frame to the current AP MLD via the wired network, and the current AP MLD receives the fast transfer probe response frame.

[0227] The Fast Transfer Probe Response (FT probe response) frame is used to respond to the Fast Transfer Probe Request frame. The Fast Transfer Probe Response frame differs from the probe response frame in its frame format, as shown in Table 4 below.

[0228] Table 4. Frame format of fast transfer probe response frames.

[0229] The FT action in Table 4 indicates that the fast transfer probe response frame is an FT action frame. The MAC addresses of the non-AP MLD and target AP MLD in Table 4 are described in Table 3 and will not be repeated here. The format of the frame body in Table 4 is the same as the frame body format of the probe response frame in S202 and will not be repeated here.

[0230] S404: The current AP MLD sends a fast transfer probe response frame to the non-AP MLD, and the non-AP MLD receives the fast probe response frame.

[0231] The current AP MLD sends fast probe response frames to the non-AP MLD via the air interface.

[0232] S405: The non-AP MLD sends a Fast Transfer Multi-Link Establishment Request Frame to the current AP MLD, and the current AP MLD receives the Fast Transfer Multi-Link Establishment Request Frame.

[0233] The Fast Transfer Multi-Link Setup Request (FT multi-link setup request) frame is used for operations such as multi-link establishment, pairwise temporary key negotiation, static context transfer indication, context renegotiation, and data forwarding indication. Its frame format is shown in Table 5 below.

[0234] Table 5. Frame format of the Fast Transfer Multi-Link Establishment Request Frame

[0235] The FT action in Table 5 indicates that the Fast Transfer Multi-Link Establishment Request frame is an FT action frame. The MAC addresses of the non-AP MLD and target AP MLD in Table 5 are described in Table 3 and will not be repeated here. The format of the frame body in Table 5 is the same as the frame body format of the reassociation request frame, which is shown in Table 6.

[0236] Table 6 shows the frame body format of the association request frame.

[0237] S406: The current AP MLD sends a Fast Transfer Multi-Link Establishment Response Frame to the non-AP MLD, and the non-AP MLD receives the Fast Transfer Multi-Link Establishment Response Frame.

[0238] The frame format of the Fast Transfer Multi-Link Setup Response (FT) frame is shown in Table 7 below.

[0239] Table 7. Frame format of fast transfer multi-link establishment response frames

[0240] The FT action in Table 5 indicates that the Fast Transfer Multi-Link Response Request frame is an FT action frame. The MAC addresses of the non-AP MLD and target AP MLD in Table 7 are described in Table 3 and will not be repeated here. The format of the frame body in Table 7 is the same as the frame body format of the reassociation response frame, which is shown in Table 8.

[0241] Table 8: Frame Body Format of Related Response Frames

[0242] S407: The non-AP MLD sends a roaming request frame to the target AP MLD, and the target AP MLD receives the roaming request frame.

[0243] S408: The target AP MLD sends a context transfer request frame to the current AP MLD, and the current AP MLD receives the context transfer request frame.

[0244] S409: The target AP MLD sends a DS-STA notification request to the DS, and the DS receives the DS-STA notification request.

[0245] S410: The current AP MLD sends a context transfer response frame to the target AP MLD, and the target AP MLD receives the context transfer response frame.

[0246] S411: The target AP MLD sends a roaming response frame to the non-AP MLD, and the non-AP MLD receives the roaming response frame.

[0247] S407-S411 refer to S305-S309 above, and will not be repeated here.

[0248] The roaming process of the centralized SMD shown in Figure 2, the roaming process of the distributed SMD shown in Figure 3, and the roaming process of the fast BSS switching shown in Figure 4 can be implemented with reference to existing technologies and will not be described in detail.

[0249] The method for generating pairwise temporary keys in the fast basic BSS handover roaming process differs from that in the SMD-based roaming process. The following describes the pairwise temporary key generation methods for both processes:

[0250] In the roaming process of Fast Basic BSS handover, the pairwise temporary keys are generated based on the MLD MAC address of the co-located AP MLD. For example, one input of the pairwise temporary key generation formula for the current AP MLD is the MLD MAC address of the current AP MLD, and one input of the pairwise temporary key generation formula for the target AP MLD is the MLD MAC address of the target AP MLD. Therefore, when a non-AP MLD switches from the current AP MLD to the target AP MLD, the pairwise temporary key must be re-negotiated and bound to the MLD MAC address of the target AP MLD.

[0251] It is worth noting that when a non-AP MLD switches from the current AP MLD to the target AP MLD, in addition to renegotiating the pairwise temporary key, a new multicast key also needs to be negotiated. Therefore, the description of renegotiating the pairwise temporary key in this application embodiment can be replaced by describing renegotiating both the pairwise temporary key and the multicast key, and the description of renegotiation of the pairwise temporary key can be replaced by describing renegotiation of both the pairwise temporary key and the multicast key.

[0252] In SMD-based roaming processes, the paired temporary keys are generated based on the SMD's MAC address. Specifically, in both centralized and distributed SMD architectures, each SMD broadcasts its own MAC address. Each AP MLD managed by an SMD generates a paired temporary key with a non-AP MLD based on the broadcast SMD's MAC address. Optionally, in one scenario, when a non-AP MLD switches between two AP MLDs within the same SMD, the paired temporary key is not regenerated or negotiated; that is, the non-AP MLD can use the same paired temporary key to transmit information with different AP MLDs managed by the same SMD. In another scenario, when a non-AP MLD switches between two AP MLDs within the same SMD, the paired temporary key is regenerated or negotiated, but the SMD's MAC address is still used during the regeneration or negotiation process.

[0253] As discussed above, the roaming processes of centralized SMD and distributed SMD differ in their steps. Specifically, the centralized SMD roaming process does not involve switching DS mappings (i.e., it does not involve the aforementioned DS-STA notification request interaction) or context transfer. Furthermore, in SMD-based roaming processes, the SMD broadcasts its own MAC address. For example, in both centralized and distributed SMD roaming processes, the SMD broadcasts its own MAC address for generating paired temporary keys. However, non-AP MLD cannot determine whether to execute a centralized or distributed SMD roaming process based on the SMD's address. Therefore, non-AP MLD cannot effectively perform seamless roaming.

[0254] To address the aforementioned issues, this application provides a communication method comprising: an access point multi-link device (APM) acquiring first information indicating the type of the SMD to which the APM belongs, wherein the SMD type is either centralized SMD or distributed SMD; and sending the first information to a non-access point multi-link device. Correspondingly, the non-access point multi-link device receives the first information and, based on the first information, executes the roaming procedure corresponding to the SMD type. Thus, the non-access point multi-link device can accurately determine whether to execute a centralized SMD roaming procedure or a distributed SMD roaming procedure based on the SMD type indicated by the first information, thereby improving roaming performance.

[0255] The communication method provided in the embodiments of this application will be described below with reference to the accompanying drawings.

[0256] The communication method provided in this application is applicable to wireless local area networks (WLANs) that support relevant standards of the Institute of Electrical and Electronics Engineers (IEEE). These IEEE standards include, but are not limited to, 802.11a / b / g, 802.11n, 802.11ac, 802.11ax, 802.11be, 802.11bn / UHR / WiFi8, 802.11ad, 802.11ay, 802.11bf / sensing, UWB / 802.15, etc.

[0257] The communication system provided in the embodiments of this application will be described below with reference to Figure 5.

[0258] Figure 5 is a schematic diagram of the architecture of a communication system provided in an embodiment of this application. As shown in Figure 5, the communication system may include a non-access point multi-link device and multiple access point multi-link devices (e.g., access point multi-link device 1 (AP MLD1) and access point multi-link device 2 (AP MLD2)). Each access point multi-link device and the non-access point multi-link device can communicate with each other through any of the multiple supported links. Optionally, AP MLD1 is the current AP MLD, and AP MLD2 is the neighboring AP MLD.

[0259] For example, Figure 6 is a schematic diagram of the architecture of a communication system in a roaming scenario provided by an embodiment of this application. In a roaming scenario, the communication system shown in Figure 6 includes an access point multi-link device 1 (AP MLD 1), an access point multi-link device 2 (AP MLD 2), and a non-access point multi-link device (non-AP MLD). The non-AP MLD includes two auxiliary STAs, such as auxiliary site 1 and auxiliary site 2; AP MLD 1 includes two auxiliary access points, such as auxiliary access point 1 and auxiliary access point 2; AP MLD 2 includes two auxiliary APs, such as auxiliary access point 1 and auxiliary access point 2.

[0260] In Figure 6, non-AP MLD, AP MLD 1, and AP MLD 2 all support two links, such as a first link and a second link. The first link and the second link operate on different frequency bands; for example, the first link operates at 2.4 GHz, and the second link operates at 5 GHz. For instance, auxiliary site 1 included in non-AP MLD 1 in Figure 6 can communicate with auxiliary access point 1 included in AP MLD 1 through the first link, and auxiliary site 2 included in non-AP MLD 1 in Figure 6 can communicate with auxiliary access point 2 included in AP MLD 1 through the second link.

[0261] In Figure 6, AP MLD 1 is the current AP MLD of the non-AP MLD, and AP MLD 2 is the target AP MLD of the non-AP MLD. That is, as the non-AP MLD moves, the non-AP MLD will roam from AP MLD 1 to AP MLD 2. At this time, the auxiliary site 1 included in the non-AP MLD will switch from the auxiliary access point 1 included in AP MLD 1 to the auxiliary access point 1 included in AP MLD 2, and the auxiliary site 2 included in the non-AP MLD will switch from the auxiliary access point 2 included in AP MLD 1 to the auxiliary access point 2 included in AP MLD 2.

[0262] Optionally, AP MLD 1 and AP MLD2 in Figure 6 may belong to the same mobility domain (MD), or the same centralized SMD, or the same distributed SMD.

[0263] The aforementioned AP MLD can communicate with one or more non-AP MLDs, and the AP MLD can also communicate with one or more other AP MLDs, and the non-AP MLD can also communicate with one or more other non-AP MLDs.

[0264] For example, the AP MLD can be a device that supports the 802.11be standard or the future Wireless Fidelity (Wi-Fi) standard, or a device that supports multiple WLAN standards; it can also be a device that supports the 802.11a / b / g, 802.11n, 802.11ac, 802.11ax, 802.11bf, 802.11be, 802.11bn / UHR / WiFi8 standards, without limitation.

[0265] For example, an AP MLD can be a terminal device with a Wi-Fi chip, network device, communication server, router, switch, bridge, computer, etc. AP MLDs can also serve as multi-link access points for mobile users to access wired networks, primarily deployed in homes, buildings, and campuses, with a typical coverage radius of tens to hundreds of meters. Of course, they can also be deployed outdoors. An AP MLD acts as a bridge connecting wired and wireless networks, its main function being to connect various wireless network clients together and then connect the wireless network to the Ethernet.

[0266] For example, a non-AP MLD can be a device that supports multiple WLAN standards such as the 802.11be standard or future Wi-Fi standards; it can also be a device that supports the 802.11a / b / g, 802.11n, 802.11ac, 802.11ax, 802.11bf, 802.11be, 802.11bn / UHR / WiFi8 standards, without limitation.

[0267] For example, a non-AP MLD can be a wireless communication chip, wireless sensor, wireless communication terminal, communication server, router, switch, bridge, computer, etc. For example, a STA MLD can be a mobile phone supporting Wi-Fi communication, a tablet computer supporting Wi-Fi communication, a set-top box supporting Wi-Fi communication, a smart TV supporting Wi-Fi communication, a smart wearable device supporting Wi-Fi communication, an in-vehicle communication device supporting Wi-Fi communication, and a computer supporting Wi-Fi communication, etc., without restriction.

[0268] It is understood that Figure 5 above is a schematic diagram and does not constitute a limitation on the applicable scenarios of the technical solutions provided in this application. Those skilled in the art should understand that in the specific implementation process, the communication system shown in Figure 5 may include fewer devices than those shown in Figure 5, or the communication system shown in Figure 5 may also include other devices. At the same time, the number of devices in the communication system shown in Figure 5 can be determined according to specific needs and is not limited.

[0269] Optionally, the devices in Figure 5 (e.g., access point multilink devices, non-access point multilink devices) can also be referred to as communication devices. They can be general-purpose devices or special-purpose devices. This application embodiment does not specifically limit them.

[0270] Optionally, the functions of each device in Figure 5 of this application can be implemented by one device, multiple devices working together, or one or more functional modules within a single device. This application does not specifically limit these functions. It is understood that the aforementioned functions can be network elements in hardware devices, software functions running on dedicated hardware, a combination of hardware and software, or virtualization functions instantiated on a platform (e.g., a cloud platform).

[0271] The communication method provided in the embodiments of this application will be described below with reference to the communication system shown in Figure 5. Actions, terminology, etc., involved in the following embodiments can be referenced interchangeably. The message names or parameter names in the messages exchanged between devices in each embodiment are merely examples, and other names may be used in specific implementations. For example, "corresponding" in the following embodiments can be replaced by "associating," etc., and "sending" in the following embodiments can be replaced by "transmitting," etc.

[0272] The following describes a communication method provided by an embodiment of this application. As shown in Figure 7, the method may include the following steps:

[0273] S701: AP MLD obtains first information.

[0274] For example, AP MLD refers to AP MLD 1 and / or AP MLD 2 in Figure 6.

[0275] The first piece of information indicates the type of SMD to which the AP MLD belongs, which is either a centralized SMD or a distributed SMD.

[0276] Optionally, the first information can be carried in any of the following: a beacon frame, a probe request frame, a neighbor report element, a reduced neighbor report element, or a newly defined seamless mobility domain element (SMD element).

[0277] The newly defined SMD element is used to carry information related to the SMD to which the AP MLD belongs. Optionally, in addition to carrying the first information, the newly defined SMD element can also carry the MAC address of the SMD to which the AP MLD belongs, and can also carry second information. The relevant description of the second information is given below and will not be repeated here.

[0278] The beacon frame is a broadcast frame periodically sent by the AP MLD. Beacon frames are primarily used for time synchronization, waking up terminals, and periodically announcing the presence of a wireless network (such as a WLAN). See the relevant description in S201 above for the probe request frame. The neighbor report element is carried in the BSS transition candidate list field of the bandwidth transfer management (BTM) query frame.

[0279] Figure 8 is a schematic diagram of the format of a neighbor report element. The neighbor report element in Figure 8 may include the following fields: element ID, length, basic service set identifier (BSS identifier, BSSID), BSSID information, operating class, channel number, physical layer type ((physical, PHY) type), and optional subelements.

[0280] The BSSID field is used to indicate the BSSID of the neighboring AP that was reported.

[0281] The BSSID information field indicates relevant information about the reported BSSID. The Operation Category field and Channel Number field indicate the channel to which the reported BSSID belongs. Optionally, the BSSID information field may include the following fields: AP reachability, security, key scope, capabilities, mobility domain, high throughput, very high throughput, fine timing measurement (FTM), high efficiency, extended range BSS (ER BSS), co-located AP, unsolicited probe response active, co-located with a 2.4 / 5GHz AP and a member of an extended service set, on-channel tunneling (OCT) supported with the reporting AP, co-located with a 6GHz AP, and reserved fields.

[0282] The Physical Layer Type field is used to indicate the physical layer type of the AP corresponding to the reported BSSID.

[0283] S702: The AP MLD sends the first message to the non-AP MLD, and the non-AP MLD receives the first message from the AP MLD.

[0284] The AP MLD and the non-AP MLD can communicate through any of the multiple links. Multiple links refer to the multiple links supported by both the AP MLD and the non-AP MLD. Therefore, the AP MLD sending the first message to the non-AP MLD can mean that the AP MLD sends the first message to the non-AP MLD through any or all of the multiple links, or it can mean that an affiliated AP included in the AP MLD sends the first message to an affiliated STA included in the non-AP MLD through the first link. The first link is the link through which the affiliated AP and the affiliated STA communicate.

[0285] Optionally, in this application, the AP MLD can transmit the information provided in the embodiments of this application, such as first information, second information, third information, fourth information, and fifth information, through broadcasting, or through signaling, without limitation. The second, third, fourth, and fifth information are described in detail below and will not be repeated here.

[0286] S703: The non-AP MLD executes the roaming process corresponding to the type of SMD indicated by the first information based on the first information.

[0287] The non-AP MLD, based on the first information, executes the roaming process corresponding to the SMD type indicated by the first information, including: if the SMD type indicated by the first information of the current AP MLD in the first information is a centralized SMD, the non-AP MLD executes the roaming process corresponding to the centralized SMD, i.e., the centralized SMD roaming process; if the SMD type indicated by the first information of the current AP MLD in the first information is a distributed SMD, the non-AP MLD executes the roaming process corresponding to the distributed SMD, i.e., the distributed SMD roaming process. The non-AP MLD can execute the centralized SMD roaming process with reference to existing technologies, such as the centralized SMD roaming process shown in Figure 2. The non-AP MLD can execute the distributed SMD roaming process with reference to existing technologies, such as the distributed SMD roaming process shown in Figure 3.

[0288] Based on the communication method shown in Figure 7, each AP MLD that provides services to the non-AP MLD sends first information indicating the type of SMD to which the AP MLD belongs. The non-AP MLD receives the first information and can then accurately determine whether to execute the roaming process of a centralized SMD or a distributed SMD based on the type of SMD indicated by the first information of the current AP MLD, thereby improving roaming performance.

[0289] When the current AP MLD is located at the edge of its SMD but not at the edge of its Extended Service Set (ESS), the non-AP MLD may need to renegotiate pairwise temporary keys when roaming to another SMD. This requires requesting the installation of the negotiated pairwise temporary key. If the non-AP MLD initiates this operation late during roaming, it may increase the duration of data transmission interruptions. However, if the non-AP MLD performs this operation earlier during roaming—for example, when connecting to the current AP MLD—the data transmission interruption duration will not be increased due to pairwise temporary key renegotiation.

[0290] For non-AP MLDs, the ESS (Essential Service Provider) edge field in the ESS report element can be used to determine whether the current AP MLD is located on the edge of the ESS to which it belongs. For example, when the ESS edge field is 0, the current AP MLD is not located on the edge of the ESS to which it belongs; when the ESS edge field is 1, the current AP MLD is located on the edge of the ESS to which it belongs. The format of the ESS report element is shown in Figure 9, and related descriptions are provided below and will not be repeated here.

[0291] However, the current AP MLD does not currently indicate to the non-AP MLD whether the current AP MLD is located at the edge of its SMD. This makes it difficult for the non-AP MLD to determine when to re-negotiate the pairwise temporary key and install the negotiated pairwise temporary key. This leads to the time spent by the non-AP MLD and the target AP MLD in performing the aforementioned operations, increasing the data interruption duration of the non-AP MLD.

[0292] Optionally, based on the above, in order to reduce the data interruption duration of non-AP MLD during roaming, the communication method shown in Figure 7 may also include step S704 (not shown in Figure 7):

[0293] S704: The AP MLD sends a second message to the non-AP MLD, and the non-AP MLD receives the second message.

[0294] The second piece of information is used to indicate whether the location of the AP MLD is located at the edge of its SMD.

[0295] Furthermore, optionally, when the second information of the current AP MLD indicates that the current AP MLD is located at the edge of its SMD, and the ESS edge field of the current AP MLD indicates that the current AP MLD is not located at the edge of its ESS, the non-AP MLD can re-negotiate and install pairwise temporary keys with the target AP MLD before connecting to the current AP MLD. This reduces the data transmission interruption time that may occur when the non-AP MLD roams to the target AP MLD. When the second information of the current AP MLD indicates that the AP MLD is not located at the edge of its SMD, the non-AP MLD does not need to re-negotiate and install pairwise temporary keys during roaming, further reducing the data interruption time of the non-AP MLD.

[0296] In this application, there are no restrictions on the information carrying the second information and the bits occupied by the second information. For example, the second information may be carried in any of the following: an ESS report element, a mobility domain element, or a newly defined SMD element.

[0297] Optionally, the first information and the second information can be carried within the same information or within different information, without restriction. For example, when the first and second information are carried within the same information, both the first and second information can be carried in any one of the beacon frame, probe request frame, neighbor report element, or newly defined SMD element. When the first and second information are carried within different information, the first information can be carried in the beacon frame, and the second information can be carried in the mobility domain element.

[0298] Figure 9 is a schematic diagram of the format of an ESS report element. The ESS report element shown in Figure 9 includes four fields, each occupying one byte (octets). The four fields are: element ID, length, element ID extension, and ESS information.

[0299] Figure 10 is a schematic diagram of the format of the ESS information field. The ESS information field shown in Figure 10 includes the following three fields: planned ESS, ESS of edge, and recommended BSS transition RSSI threshold within ESS.

[0300] The planned ESS field occupies 1 bit. The planned ESS field indicates whether the BSS is part of an overlapping ESS deployment containing multiple BSSs. A planned ESS field set to 1 indicates that the deployed ESS can guarantee coverage of the AP MLD. If the planned ESS field is set to 0, the ESS edge field and the received signal strength indication threshold field for recommended BSS transfer within the ESS are reserved.

[0301] The ESS edge field occupies 1 bit. The ESS edge field indicates whether the BSS is at the edge of the ESS. A value of 1 indicates that the BSS is at the ESS edge. A value of 0 indicates that the BSS is not at the ESS edge.

[0302] A BSS (Basic Service Unit) is a wireless network consisting of one AP MLD (Multi-Access Point) and several non-AP MLDs. Specifically, the area covered by one AP MLD constitutes a BSS, and all non-AP MLDs within the BSS communicate through that AP. Therefore, non-AP MLDs can determine whether the AP MLD is located at the ESS (Essential Service Module) edge using the ESS edge field. For example, an ESS edge field set to 1 indicates that both the BSS and the AP MLD are located at the ESS edge. An ESS edge field set to 0 indicates that neither the BSS nor the AP MLD is located at the ESS edge.

[0303] The Received Signal Strength Indication (RSSI) threshold field for recommending BSS transfer within an ESS occupies 6 bits. This field indicates the RSSI. If the RSSI measured by the current AP MLD is below this threshold, the STA associated with the current AP MLD is recommended to initiate a BSS transfer; that is, the associated STA transfers from its current BSS to a neighboring BSS within the same ESS.

[0304] In this application, when the AP MLD shown in Figure 7 is the current AP MLD, the execution order of step S704 and steps S701-S703 is not limited. For example, step S704 can be executed before any of the steps between S701-S703; or step S704 can be executed after step S703; or step S704 can be executed simultaneously with step S702.

[0305] Optionally, to prevent the non-AP MLD from obtaining information about neighboring AP MLDs by scanning neighboring AP MLDs over the air interface, or to enable the non-AP MLD to select a suitable target AP MLD based on relevant information of neighboring AP MLDs, the communication method shown in Figure 7 may also include S705 and / or S706 (not shown in Figure 7):

[0306] S705: When AP MLD is a neighboring AP MLD of non-AP MLD, AP MLD sends third information to non-AP MLD, and non-AP MLD receives the third information.

[0307] The third piece of information is used to indicate whether the SMD of the neighboring AP MLD is the same as the SMD of the current AP MLD of the non-AP MLD.

[0308] Based on the S705 procedure, non-AP MLDs can better select suitable neighboring AP MLDs as target AP MLDs. For example, based on the third information of each neighboring AP MLD, the non-AP MLD determines whether the SMD to which each neighboring AP MLD belongs is the same as the SMD to which the current AP MLD of the non-AP MLD belongs. Since the non-AP MLD does not need to regenerate or negotiate paired temporary keys when switching between two AP MLDs within the same SMD, it can prioritize selecting neighboring AP MLDs belonging to the same SMD as target AP MLDs to reduce the latency of the roaming handover process.

[0309] Optionally, the third information can be carried in the neighbor report element. The neighbor report element is described in S701 and will not be repeated here. In this application, there is no limitation on the number of bits occupied by the third information; for example, the third information can occupy 1 bit in the neighbor report element.

[0310] In this application, when the AP MLD shown in Figure 7 is a neighboring AP MLD, the execution order of step S704 and steps S701-S703 is not limited. For example, step S704 can be executed before any of the steps between S701-S703; or step S704 can be executed after step S703; or step S704 can be executed simultaneously with step S702.

[0311] S706: The AP MLD sends the fourth message to the non-AP MLD, and the non-AP MLD receives the fourth message.

[0312] Similarly, step S706 may include: each AP MLD that supports providing services to the non-AP MLD sends its own fourth information to the non-AP MLD, and correspondingly, the non-AP MLD receives the fourth information from each AP MLD that supports providing services to the non-AP MLD.

[0313] The fourth information is used to provide information about neighboring AP MLDs for non-AP MLDs. The fourth information includes at least one of the following: a robust secure network subelement (RSN subelement), a robust secure network extension subelement (RSN extension subelement), a support rates and BSS membership selectors subelement (support rates and BSS membership selectors subelement), and an extended support rates and BSS membership selectors subelement (extended support rates and BSS membership selectors subelement). The robust secure network subelement, the robust secure network extension subelement, the support rates and BSS membership selectors subelement, and the extended support rates and BSS membership selectors subelement are described in the protocol and will not be repeated here.

[0314] Optionally, the fourth piece of information can be carried in the neighbor report element. See the relevant description in S701 for the neighbor report element; it will not be repeated here.

[0315] Based on step S706, compared to non-AP MLD obtaining information about neighboring AP MLDs by scanning neighboring AP MLDs over the air interface, non-AP MLD directly obtains relevant information about each neighboring AP MLD through the fourth information sent by the current AP MLD. Thus, non-AP MLD can select a suitable neighboring AP MLD as the target AP MLD based on the content carried by the fourth information, reducing the latency of the roaming handover process.

[0316] In this application, there is no restriction on the execution order between step S706 and steps S701-S703. For example, step S706 may be executed before any of the steps between S701-S703; or step S706 may be executed after step S703; or step S704 may be executed simultaneously with step S702.

[0317] In the roaming process of fast BSS handover described above (see Figure 4), since the target AP MLD sends the fast transfer probe response frame to the current AP MLD not through the air interface but through the wired network, a random delay is introduced, namely the delay caused by wired transmission. This results in the timestamp in the fast transfer probe response frame received by the current AP MLD being inaccurate. At this time, depending on whether the target AP MLD and the current AP MLD follow the wired time synchronization protocol, the current AP MLD sends a fast probe response frame to the non-AP MLD, i.e., step S404. There are two possible scenarios:

[0318] Scenario 1: If the target AP MLD and the current AP MLD follow a wired time synchronization protocol, such as the 802.1 precision time protocol (802.1AS), and the current AP MLD sends a multi-link element with a time synchronization function (TSF) offset present of 0, then after receiving the fast transfer probe response frame, the current AP MLD needs to replace the timestamp in the fast transfer probe response frame with the timestamp of the current link in the current AP MLD. The current link refers to the link currently in use between the current AP MLD and the non-AP MLD. Then, it sends the fast transfer probe response frame with the replaced timestamp to the non-AP MLD via the air interface.

[0319] Scenario 2: If the target AP MLD and the current AP MLD do not follow the wired time synchronization protocol, after the current AP MLD receives the fast transfer probe response frame, it can set the timestamp in the fast transfer probe response frame to a special value (such as all 1s) to indicate that the time error is invalid, and then fast transfer and send the fast transfer probe response frame to the non-AP MLD through the air interface.

[0320] As mentioned above, the non-AP MLD needs to know whether the target AP MLD and the current AP MLD follow a wired time synchronization protocol to determine if the timestamp in the Fast Transfer Probe Response (FTP) frame is accurate. If the timestamp in the FTP frame is accurate, the non-AP MLD can perform time synchronization based on that timestamp. Otherwise, it needs to perform time synchronization with the target AP MLD via the air interface.

[0321] To address the aforementioned issues, this application provides another communication method. The method includes: the current AP MLD acquiring fifth information, which is used by the non-AP MLD to determine whether the clock of the current AP MLD is synchronized with the clock of a neighboring AP MLD; the current AP MLD sending the fifth information to the non-AP MLD, and the non-AP MLD receiving the fifth information from the current AP MLD. Both the current AP MLD and the non-AP MLD are MLDs. Thus, the non-AP MLD can determine, based on the fifth information, whether the clock of the current AP MLD is synchronized with the clock of a reported neighboring AP MLD. The target AP MLD is one of the reported neighboring AP MLDs. Furthermore, the non-AP MLD can determine, based on the fifth information, whether the clock of the current AP MLD is synchronized with the clock of the target AP MLD, determine whether the timestamp in the fast transfer probe response frame is accurate, and perform different operations based on the accuracy of the timestamp, so that the non-AP MLD and the target AP MLD can perform time synchronization-related operations. For example, if the timestamp in the fast transfer probe response frame is accurate, the non-AP MLD can directly perform time synchronization-related operations based on that timestamp and the target AP MLD; if the timestamp in the fast transfer probe response frame is inaccurate, the non-AP MLD can obtain the accurate timestamp of the target AP MLD through the air interface, and then perform time synchronization-related operations based on the timestamp obtained through the air interface and the target AP MLD. Another communication method provided by an embodiment of this application is described below. As shown in Figure 11, this method may include the following steps:

[0322] S1101: The current AP MLD obtains the fifth information.

[0323] Specifically, the fifth piece of information obtained by the current AP MLD includes: the fifth piece of information obtained by the current AP MLD for each neighboring AP MLD. The neighboring AP MLDs include the target AP MLD.

[0324] The fifth piece of information is used by the non-AP MLD to determine whether the clock of the current AP MLD is synchronized with the clock of the neighboring AP MLD. A detailed description of the fifth piece of information can be found in the relevant description in S1102.

[0325] S1102: The current AP MLD sends the fifth message to the non-AP MLD, and the non-AP MLD receives the fifth message.

[0326] S1102 includes: the current AP MLD sending the reported fifth information of the neighboring AP MLD to the non-AP MLD, and the non-AP MLD receiving the reported fifth information of the neighboring AP MLD.

[0327] The reported neighbor AP MLDs can be some or all of the neighbor AP MLDs, without restriction. For example, if the fifth information is carried in the neighbor report element, the corresponding neighbor AP MLD is the neighbor AP MLD indicated by the neighbor report element; if the fifth information is carried in the beacon frame, or if the fifth information indicates that the clocks of each AP MLD in the SMD to which the current AP MLD belongs are synchronized, the corresponding neighbor AP MLD is all of the neighbor AP MLDs.

[0328] In this application, the current AP MLD can directly or indirectly indicate to the non-AP MLD, based on the fifth information, whether the clock of the current AP MLD and the clock of the neighboring AP MLD are the same. The specific indication methods include the following two cases:

[0329] Scenario 1: If the SMD to which the current AP MLD belongs is the same as the SMD to which each neighboring AP MLD belongs, the fifth information indicates that the clocks of each AP MLD in the SMD to which the current AP MLD belongs are synchronized.

[0330] In this scenario, after receiving the fifth information, the non-AP MLD can determine, based on this information, that the clocks of each AP MLD within the SMD to which the current AP MLD belongs are synchronized. Each neighboring AP MLD is an AP MLD within the SMD to which the current AP MLD belongs. Thus, the non-AP MLD can indirectly determine that the clocks of the current AP MLD and neighboring AP MLDs are synchronized. Since the neighboring AP MLD includes the target AP MLD, the non-AP MLD can further determine that the clocks of the current AP MLD and the target AP MLD are synchronized, thus confirming the accuracy of the timestamp in the received fast transfer probe response frame.

[0331] Optionally, in this case, the fifth piece of information can be carried in a mobile domain element or a newly defined SMD element.

[0332] Case 2: The fifth information indicates whether the clocks of the current AP MLD and the neighboring AP MLD are synchronized.

[0333] In this scenario, after the non-AP MLD receives the fifth information from each neighboring AP MLD, which includes the fifth information of the target AP MLD, the non-AP MLD directly determines whether the clocks of the current AP MLD and the target AP MLD are the same based on the indication of the target AP MLD's fifth information. If the target AP MLD's fifth information indicates that the clocks of the current AP MLD and the target AP MLD are the same, the current time synchronization function offset in the multi-link element sent by the current AP MLD is set to 0, and the timestamp in the fast transfer probe response frame is both the current AP MLD's and the target AP MLD's timestamp. The non-AP MLD directly performs time-related operations based on the timestamp in the fast transfer probe response frame and the target AP MLD. If the target AP MLD's fifth information indicates that the clocks of the current AP MLD and the target AP MLD are different, the current time synchronization function offset in the multi-link element sent by the current AP MLD is set to 1, and the timestamp in the fast transfer probe response frame can be set to 0. In this case, the non-AP MLD needs to obtain the target AP MLD's information via the air interface. The accurate timestamp of the MLD, and then operations related to the time of the target AP MLD execution based on the timestamp obtained from the air interface.

[0334] Optionally, in this case, the fifth piece of information can be carried in a neighbor report element or a reduced neighbor report element. The reduced neighbor report element is described in the protocol and will not be repeated here.

[0335] In this application, there is no limit to the number of bits occupied by the fifth piece of information. For example, the fifth piece of information can occupy 1 bit.

[0336] Optionally, the communication method shown in Figure 11 can be executed before, simultaneously with, or after step S404 in Figure 4, without restriction.

[0337] In addition to the seamless roaming process shown in Figures 2 to 11 above, the seamless roaming process may also include the following operations: context transfer, Internet Protocol (IP) address continuation, and data forwarding.

[0338] Context transfer can be used to transmit configuration information for the current AP MLD, such as the block acknowledgment session context. Context transfer is described in the relevant documentation and will not be elaborated upon here.

[0339] The Internet Protocol address remains unchanged, which can be used to indicate that when roaming from the current AP MLD to the target AP MLD, the IP address of the non-AP MLD does not need to be updated. That is, the non-AP MLD does not need to request a new IP address from the server and continues to use the original IP address to send data to the target AP MLD.

[0340] Data fronthaul includes the current AP MLD forwarding any untransmitted downlink MAC service data unit (MSDU) to the target AP MLD, and then the target AP MLD sending the untransmitted downlink MSDU from the current AP MLD to the non-AP MLD; it may even include the target AP MLD forwarding the received uplink MSDU to the current AP MLD, and then the current AP MLD delivering the received uplink MSDU to the LLC layer and DS in sequence.

[0341] Currently, the 802.11 protocol does not explicitly define the relationship between Internet Protocol address immutability and data fronthaul. For example, when a non-AP MLD roams from the current AP MLD to the target AP MLD, it needs to request a new IP address from the server again. That is, the non-AP MLD needs to update its IP address. Furthermore, the non-AP MLD uses the new IP address to send information to the target AP MLD, and the current AP MLD initiates data fronthaul. After the current AP MLD initiates data fronthaul, it forwards any untransmitted downlink MSDUs to the target AP MLD. The target AP MLD then uses the new IP address to send the untransmitted downlink MSDUs from the current AP MLD to the non-AP MLD. However, when the current AP MLD and the target AP MLD are connected to the same AP address server, the non-AP MLD does not need to request a new IP address from the server again. In other words, the IP address of the non-AP MLD can remain unchanged. If the non-AP MLD still roams from the current AP MLD to the target AP MLD according to the above operation, it will request a new IP address from the server again. Then the current AP MLD will start data forwarding again, introducing additional latency, increasing the latency of data forwarding and the duration of the roaming process.

[0342] To address the aforementioned issues, this application provides another communication method, comprising: the current AP MLD acquiring sixth information; determining the content of seventh information based on the sixth information; and sending the sixth and seventh information. Correspondingly, the non-AP MLD receives the sixth and seventh information. The sixth information is used by the non-AP MLD to determine whether a new IP address needs to be requested when roaming from the current AP MLD to the target AP MLD, and the seventh information is used by the non-AP MLD to determine whether data forwarding is supported between the current AP MLD and the target AP MLD. Thus, if the non-AP MLD determines, based on the sixth information, that a new IP address is not needed when roaming from the current AP MLD to the target AP MLD, and based on the seventh information, that data forwarding is supported between the current AP MLD and the target AP MLD, then the non-AP MLD will not request a new IP address from the server again, but will use the original IP address for data forwarding, reducing data forwarding latency and roaming latency.

[0343] The following describes another communication method provided by an embodiment of this application. As shown in Figure 12, the method may include the following steps:

[0344] S1201: The current AP MLD obtains the sixth information.

[0345] The sixth piece of information is used by the non-AP MLD to determine whether a new IP address needs to be requested when roaming from the current AP MLD to the target AP MLD.

[0346] In this application, the current AP MLD can directly or indirectly instruct the non-AP MLD, based on the sixth information, whether a new IP address needs to be requested when roaming from the current AP MLD to the target AP MLD. The specific instruction methods include the following two cases:

[0347] Scenario 1: When a non-AP MLD roams between two AP MLDs within the same SMD (Site Detail), and the IP address of the non-AP MLD remains unchanged or does not need to be updated, the sixth information indicates whether the SMD of the current AP MLD and the SMD of the target AP MLD are the same. This indirectly indicates whether the non-AP MLD needs to request a new IP address when roaming from the current AP MLD to the target AP MLD. For example, if the sixth information indicates that the SMD of the current AP MLD and the SMD of the target AP MLD are the same, it indirectly indicates that the non-AP MLD does not need to request a new IP address when roaming from the current AP MLD to the target AP MLD. If the sixth information indicates that the SMD of the current AP MLD and the SMD of the target AP MLD are different, it indirectly indicates that the non-AP MLD needs to request a new IP address when roaming from the current AP MLD to the target AP MLD.

[0348] Scenario 2: The sixth information indicates whether a non-AP MLD needs to request a new IP address when roaming from the current AP MLD to the target AP MLD.

[0349] Optionally, in this possible case, the sixth information may be carried in at least one of the neighbor report element and the simplified neighbor report element.

[0350] S1202: The current AP MLD sends the sixth and seventh information based on the sixth information; the non-AP MLD receives the sixth and seventh information.

[0351] The seventh piece of information is used by the non-AP MLD to determine whether data forwarding is supported between the current AP MLD and the target AP MLD.

[0352] In this application, the current AP MLD can directly or indirectly indicate to the non-AP MLD, based on the seventh information, whether data fronthaul is supported between the current AP MLD and the target AP MLD. The specific indication methods include the following two cases:

[0353] Scenario 1: When two AP MLDs within the same SMD (Signal Module) roam between a predefined / default non-AP MLD, and the current AP MLD and target AP MLD support data fronthaul, the seventh information indicates whether the SMD of the current AP MLD and the target AP MLD are the same, indirectly indicating whether data fronthaul is supported between them. For example, if the seventh information indicates that the SMD of the current AP MLD and the target AP MLD are the same, it indirectly indicates that data fronthaul is supported between them. If the seventh information indicates that the SMD of the current AP MLD and the target AP MLD are different, it indirectly indicates that data fronthaul is not supported between them.

[0354] Case 2: The seventh information indicates whether data forwarding is supported between the current AP MLD and the target AP MLD.

[0355] Optionally, in this possible case, the seventh information may be carried in at least one of the neighbor report element and the simplified neighbor report element.

[0356] Specifically, the current AP MLD sends the sixth and seventh messages based on the sixth message, including: if the sixth message indicates that the non-AP MLD does not need to request a new IP address when roaming from the current AP MLD to the target AP MLD, the seventh message indicates that data forwarding is supported between the current AP MLD and the target AP MLD; if the sixth message indicates that the non-AP MLD needs to request a new IP address when roaming from the current AP MLD to the target AP MLD, the seventh message indicates that data forwarding is not supported between the current AP MLD and the target AP MLD.

[0357] In this application, the sixth and seventh information can be carried in the same information or in different information. For example, if the sixth information indicates whether a new IP address needs to be requested when a non-AP MLD roams from the current AP MLD to the target AP MLD, and the seventh information indicates whether data forwarding is supported between the current AP MLD and the target AP MLD, then if the sixth and seventh information are carried in the same information, both information is carried in the neighbor report element; if the sixth and seventh information are carried in different information, the sixth information can be carried in the neighbor report element and the seventh information in the mobility domain element; or the sixth information can be carried in the simplified neighbor report element and the seventh information in the mobility domain element; or the sixth information can be carried in the simplified neighbor report element and the seventh information in the neighbor report element, without restriction.

[0358] Optionally, this application does not limit the number of bits occupied by the sixth information. For example, the sixth information occupies 1 bit.

[0359] Optionally, this application does not limit the number of bits occupied by the seventh information. For example, the seventh information may occupy 1 bit.

[0360] In a special design, the sixth and seventh information are carried in the same message and shared by one bit. This message can be used to indicate whether data fronthaul is supported between the current AP MLD and the target AP MLD. When this message indicates that data fronthaul is supported between the current AP MLD and the target AP MLD, by default, the non-AP MLD does not need to request a new IP address when roaming from the current AP MLD to the target AP MLD. In other words, the non-AP MLD does not need to request a new IP address when roaming from the current AP MLD to the target AP MLD, or its IP address remains unchanged or is not updated. This is a prerequisite for supporting data fronthaul between the current AP MLD and the target AP MLD.

[0361] Optionally, when a non-AP MLD determines, based on the sixth piece of information, that it is roaming from the current AP MLD to the target AP MLD, it does not need to request a new IP address. If, based on the seventh piece of information, it determines that data fronthaul is supported between the current AP MLD and the target AP MLD, the non-AP MLD will not request a new IP address from the server again, but will use the original IP address for data fronthaul, reducing data fronthaul latency and roaming latency, and will request the current AP MLD to enable data fronthaul. Conversely, if, based on the sixth piece of information, it determines that it needs to request a new IP address when roaming from the current AP MLD to the target AP MLD, and based on the seventh piece of information, it determines whether data fronthaul is supported or not between the current AP MLD and the target AP MLD, then the non-AP MLD will prohibit or not allow requests for data fronthaul from the current AP MLD, reducing the roaming process time.

[0362] Furthermore, the 802.11 protocol does not explicitly define the relationship between context transfer and data fronthaul, which can easily lead to a situation where, even if the current AP MLD does not enable (or disables) data fronthaul, context transfer still occurs between the non-AP MLD, the current AP MLD, and the target AP MLD during roaming, resulting in a waste of air interface resources during roaming.

[0363] To address the aforementioned issues, this application provides another communication method, comprising: the current AP MLD acquiring eighth and ninth information, sending the eighth and ninth information to the non-AP MLD, and correspondingly, the non-AP MLD receiving the eighth and ninth information. The eighth information indicates whether to request data forwarding, and the ninth information indicates whether to request context transfer. One possible implementation is that when the eighth information indicates enabling data forwarding, the ninth information must indicate enabling context transfer; when the eighth information indicates disabling forwarding, the ninth information can indicate disabling context transfer. This ensures that the non-AP MLD enables context transfer when the eighth information indicates enabling data forwarding. This avoids the problem of the non-AP MLD still performing context transfer even when the eighth information indicates that the current AP MLD does not enable (or disables) data forwarding, thus preventing the waste of air interface resources during roaming.

[0364] The following describes another communication method provided by an embodiment of this application. As shown in Figure 13, the method may include the following steps:

[0365] S1301: The current AP MLD obtains the eighth and ninth information.

[0366] The eighth piece of information is used to indicate whether to request data forwarding.

[0367] Optionally, the eighth piece of information can be carried in / beared in one of the following frames: Fast Transfer Multi-Link Setup Request (FT), Link Reconfiguration Request (LRP), or Roaming Request (ROAM). When the current AP MLD receives a request to enable data fronthaul, it utilizes the newly defined MAC data fronthaul service, such as the defined MA-UNITDATA-FORWARDING.Request.

[0368] (

[0369] source address

[0370] Destination address

[0371] Routing information

[0372] data

[0373] Priority

[0374] Drop instructions (drop eligible)

[0375] Service class

[0376] station vector

[0377] MSDU format

[0378] Radio environment request vector (11bd)

[0379] Stream classification service identifier (SCSID)

[0380] Serial number (SN)

[0381] )

[0382] The serial number SN in the MA-UNITDATA-FORWARDING.Request defined above is used to ensure on-demand delivery. The information other than the serial number SN has the same meaning as the corresponding information in the existing MA-UNITDATA.Request.

[0383] The ninth piece of information is used to indicate whether to request context transmission.

[0384] In this application, when the eighth information indicates that data forwarding is enabled, the ninth information indicates that context transfer is enabled; when the eighth information indicates that data forwarding is disabled, the ninth information may indicate that context transfer is enabled or disabled.

[0385] S1302: The current AP MLD sends the eighth and ninth messages, and the non-AP MLD receives the eighth and ninth messages.

[0386] Optionally, the eighth and ninth information can be carried in the same information and sent, or they can be carried in different information and sent. For example, if the eighth and ninth information are carried in the same information and sent, both the eighth and ninth information are carried in the mobile domain element and sent.

[0387] In a special design, the eighth and ninth messages are carried in the same message and sent together. For example, they can both be carried in the newly defined data forwarding and context transfer support field in the mobile domain element, and the eighth and ninth messages share 1 bit. For example, the newly defined data forwarding and context transfer support field occupies 1 bit. In this case, the message is used to indicate whether data forwarding and context transfer are supported.

[0388] The roaming process in any of Figures 2-13 above can also include a stream classification service (SCS) mechanism. Under the SCS mechanism, the AP MLD associated with the non-AP MLD, such as the current AP MLD and / or the target AP MLD, can optimize the scheduling of the non-AP MLD by using the quality of service (QoS) parameters corresponding to the low-latency service flow reported by the non-AP MLD, thereby reducing the latency of the low-latency service flow.

[0389] The SCS mechanism includes: the non-AP MLD sending an SCS request frame to the current AP MLD. Correspondingly, the current AP MLD receives the SCS request frame and, in response, sends an SCS response frame to the non-AP MLD.

[0390] Optionally, the SCS mechanism can be applied to the roaming preparation phase of any of the roaming flows shown in Figures 2-13. For example, the SCS request frame is carried in the link reconfiguration establishment request frame in the roaming flows shown in Figures 2 and 3, and correspondingly, the SCS response frame is carried in the link reconfiguration establishment response frame in the roaming flows shown in Figures 2 and 3. As another example, the SCS request frame is carried in the fast transfer multi-link establishment request frame in the roaming flow shown in Figure 4, and correspondingly, the SCS response frame is carried in the fast transfer multi-link establishment response frame in the roaming flow shown in Figure 4.

[0391] An SCS request frame is used to indicate a low-latency service flow and the corresponding QoS parameters. The frame format of an SCS request frame is shown in Figure 14. The SCS request frame includes the following fields: category, robust action, dialog token, and SCS descriptor list. The category field indicates the category to which the action frame belongs. The robust action field distinguishes different frames within the same category. The dialog token field ensures the order and association of frames. The SCS descriptor list field contains one or more SCS descriptors.

[0392] The format of the SCS descriptor is shown in Figure 15. The SCS descriptor includes: element ID, length, SCS ID, request type, intra-access category priority element (optional), TCLAS element, TCLAS processing element (optional), QoS characteristics element, and optional subelements.

[0393] The SCS identifier indicates the identifier assigned to the SCS stream, and the SCS identifier occupies 1 byte. The SCS stream refers to the low-latency service stream indicated by the SCS request frame.

[0394] The request type indicates the type of request, occupying 1 byte. The request type is one of add, remove, or change. When the request type is set to 0, the request type is add; when the request type is set to 1, the request type is remove; and when the request type is set to 2, the request type is change.

[0395] The format of the priority element within an access category is shown in Figure 16. The priority element within an access category occupies 1 byte and includes: element ID, length, and intra-access priority. The intra-access priority includes user priority, alternate queue, drop eligibility, and reserved. User priority occupies 3 bits, indicating the user's priority. Alternate queue occupies 1 bit, indicating whether a new alternate queue should be created for this SCS flow. Drop eligibility occupies 1 bit, indicating whether packets for this SCS flow can be dropped when there are insufficient resources.

[0396] The flow classification element indicates how to identify the SCS flow. The flow classification element carries the criteria for determining the SCS flow. An SCS descriptor can carry one or more flow classification elements.

[0397] The stream classification processing element indicates how to process multiple stream classification elements when they exist.

[0398] The Quality of Service (QoS) feature element is used to indicate the TID (traffic identifier) ​​mapped to the SCS flow and the corresponding QoS parameters. See Table 9 for the format of the QoS feature element.

[0399] Table 9: Format of Service Quality Feature Elements

[0400] In Table 9, the delay bound indicates the maximum allowed delay for low-latency traffic flows (or low-latency packets), in microseconds. MSDU delivery information includes the MSDU delivery ratio and the MSDU count exponent. The MSDU delivery ratio indicates the required MSDU delivery rate under a given delay bound. The service start time is an unsigned integer specifying the expected time for the start of traffic for the associated TID, in microseconds. Control information includes direction, service identifier (TID), user priority, a presence bitmap of additional parameters, link ID, and reserved. The format of the control information is shown in Table 10. Other information in Table 9 is described in the relevant prior art and will not be repeated here.

[0401] Table 10: Format of Control Information

[0402] In Table 10, the direction indicates the transmission direction of the SCS stream. The direction can be set to one of 00, 10, 01, or 11, with 11 being a reserved value. When the direction is set to 00, the transmission direction of the SCS stream is uplink; when the direction is set to 10, the transmission direction is downlink; and when the direction is set to 01, the transmission direction is a direct link (peer-to-peer, P2P). The service identifier can be set to any integer from 0 to 15, with 8-15 being reserved values. The user priority can be set to any integer from 0 to 7. The user priority is set to the same value as the service identifier. The link identifier indicates the link corresponding to the direct link transmission.

[0403] The frame format of the SCS response frame is shown in Figure 17. The SCS response frame includes the following fields: category, robust action, dialog token, count, SCS status list, and SCS descriptor list. The category field indicates the category to which the action frame belongs. The robust action field is used to distinguish different frames within the same category. The dialog token field is consistent with the dialog token field in the SCS request frame. The count field indicates the number of SCS identifiers (SCS IDs) and status codes contained in the SCS status list field. The SCS status list field contains one or more SCS status groups, each carrying two subfields: SCS identifier (SCS ID) and status code. The SCS identifier indicates the identifier of the SCS. The status code indicates whether the requested SCS ID is accepted. The SCS descriptor list field contains one or more SCS descriptors. See the related descriptions above for details on SCS descriptors.

[0404] Optionally, the SCS mechanism also includes one or more of the following: SCS context transfer and SCS context renegotiation. SCS context transfer refers to the current AP MLD forwarding part of the information carried in the SCS request frame to the target AP MLD, so that the target AP MLD can accurately schedule the non-AP MLD. SCS context renegotiation refers to the non-AP MLD and the target AP MLD renegotiating the QoS parameters under the SCS mechanism.

[0405] In one example, either the current AP MLD or the target AP MLD receives a roaming request frame from a non-AP MLD carrying a time indication information. This time indication information indicates the start time / moment for the target AP MLD to schedule the non-AP MLD. Accordingly, when the time / moment indicated by the time indication information arrives, the target AP MLD schedules the non-AP MLD. However, the start time / moment for the target AP MLD to schedule the corresponding SCS flow service for the non-AP MLD is related to the transmission time of the roaming request frame. This causes the start time / moment for the target AP MLD to schedule the corresponding SCS flow service for the non-AP MLD to change with the transmission time of the roaming request frame. For different transmission times of the roaming request frame, the start time / moment for the target AP MLD to schedule the corresponding SCS flow service for the non-AP MLD needs to be updated in a timely manner, making the determination of the start time / moment for the target AP MLD to schedule the non-AP MLD quite complex.

[0406] To reduce the complexity of determining the start time / moment of scheduling non-AP MLDs by the target AP MLD, embodiments of this application provide a communication method. This method includes: the target AP MLD acquiring a first service start time; and, upon reaching the first service start time, initiating the scheduling of the non-AP MLD. The first service start time is obtained by calibrating a second service start time using the timing synchronization function (TSF_offset) offset between the current AP MLD and the target AP MLD. The second service start time is the service start time negotiated when the non-AP MLD and the current AP MLD establish an SCS session. The service start time negotiated when the non-AP MLD and the current AP MLD establish an SCS session is the same as the service start time in the aforementioned SCS request frame. Thus, compared to the target AP MLD scheduling non-AP MLD start time / time being obtained from the roaming request frame transmission time, the target AP MLD scheduling non-AP MLD start time / time is obtained after calibrating the second service start time using the TSF_offset between the current AP MLD and the target AP MLD. The target AP MLD scheduling non-AP MLD start time / time no longer changes with the roaming request frame transmission time, reducing the complexity of the target AP MLD determining the scheduling start time / time of the non-AP MLD. Figure 18 shows another communication method provided by an embodiment of this application, which includes S1801 and S1802:

[0407] S1801: target AP MLD obtains the first service start time.

[0408] The first service start time is obtained by calibrating the second service start time using the TSF_offset between the current AP MLD and the target AP MLD. The second service start time (denoted as T0) is the service start time negotiated when the non-AP MLD and the current AP MLD establish an SCS session.

[0409] In one example, the first service start time is obtained by calibrating the second service start time using the TSF_offset between the current AP MLD and the target AP MLD. This includes the first service start time being the sum of the TSF_offset between the current AP MLD and the target AP MLD and the second service start time. In other words, the first service start time equals the sum of the TSF_offset between the current AP MLD and the target AP MLD plus the second service start time; that is, first service start time = TSF_offset between the current AP MLD and the target AP MLD + T0.

[0410] Optionally, the naming of the first service start time is not limited in this application; for example, the first service start time can be named the target service start time or the calibrated service start time. The naming of the second service start time is also not limited in this application; for example, the second service start time can be named the initial service start time or the service start time before calibration.

[0411] The TSF_offset between the current AP MLD and the target AP MLD is obtained by subtracting the TSF value of the reference link corresponding to the current AP MLD (denoted as TSF_current) from the TSF value of the reference link (or other link) corresponding to the target AP MLD (denoted as TSF_target). The reference link is the link corresponding to the service start time link ID negotiated when the non-AP MLD and the current AP MLD establish an SCS session. The service start time link ID negotiated when the non-AP MLD and the current AP MLD establish an SCS session is the link identifier of the current AP MLD; that is, the reference link is the link corresponding to the link identifier of the current AP MLD. The reference link can be alternatively described as the SCS flow service start time reference link. Other links are any links between the non-AP MLD and the target AP MLD other than the reference link.

[0412] In one example, the TSF_offset between the current AP MLD and the target AP MLD is obtained by directly subtracting TSF_current and TSF_target. For example, the TSF_offset between the current AP MLD and the target AP MLD is the difference between TSF_current and TSF_target, that is, TSF_offset = TSF_target - TSF_current.

[0413] In another example, the TSF_offset between the current AP MLD and the target AP MLD is the result of subtracting TSF_current and TSF_target, followed by other operations. For instance, with two's complement encoding and a service start time unit of 2 microseconds (μs), the TSF offset between the current AP MLD and the target AP MLD is the difference between TSF_current and TSF_target, divided by 2, and then rounded down.

[0414] This application does not limit the method by which the target AP MLD obtains the first service start time. For example, the target AP MLD can directly obtain the first service start time through the current AP MLD, as described in the first implementation method below; or the target AP MLD can indirectly obtain the first service start time by obtaining the TSF_offset between the current AP MLD and the target AP MLD and the second service start time, as described in the second or third implementation method below; or the target AP MLD can directly obtain the first service start time through the non-AP MLD, as described in the fourth implementation method below.

[0415] Optionally, the target AP MLD's acquisition of the first service start time includes: the target AP MLD's acquisition of the first service start time, and the acquisition of the reference link identifier of the target AP MLD. The reference link identifier of the target AP MLD refers to the link identifier corresponding to TSF_target. For example, if TSF_target is the TSF of link 1 (i.e., link identifier 1) of the target AP MLD, then the reference link identifier of TSF_target is 1.

[0416] Optionally, the target AP MLD can obtain the reference link identifier of the target AP MLD through the non-AP MLD or the current AP MLD. For example, the target AP MLD receives the updated QoS characteristic element from the current AP MLD; or, the target AP MLD receives the eleventh piece of information from the non-AP MLD, which carries the reference link identifier of the target AP MLD; or, the target AP MLD receives the updated QoS characteristic element from the non-AP MLD. In this case, the service start time link identifier in the updated QoS characteristic element is the reference link identifier of the target AP MLD. The updated QoS characteristic element and the eleventh piece of information are described in the relevant descriptions below and will not be repeated here.

[0417] S1802: When the target AP MLD arrives at the first service start time, the non-AP MLD will be scheduled.

[0418] Among them, non-AP MLD refers to the non-AP MLD that is about to roam from the current AP MLD to the target AP MLD.

[0419] The process of scheduling non-AP MLDs when the target AP MLD arrives at the first service start time includes: when the target AP MLD arrives at the first service start time, scheduling non-AP MLDs in the link corresponding to the reference link identifier of the target AP MLD.

[0420] Optionally, the method shown in Figure 18 corresponds to different implementations under different operations in the SCS mechanism. For example, under SCS context transfer in the SCS mechanism, the method shown in Figure 18 corresponds to any one of the first to third implementations described below; under SCS context renegotiation in the SCS mechanism, the method shown in Figure 18 corresponds to the fourth implementation described below. The various implementations are described below.

[0421] In the first implementation: The current AP MLD receives the TSF_offset between the current AP MLD and the target AP MLD from the non-AP MLD, as well as the reference link identifier (link ID) of the target AP MLD. Further, before performing an SCS context transfer, the current AP MLD updates the service start time in the QoS feature element to a first service start time, and updates the service start time link identifier in the QoS feature element to the reference link identifier of the target AP MLD. Then, during the SCS context transfer, the current AP MLD sends the updated QoS feature element to the target AP MLD, enabling the target AP MLD to obtain the first service start time and the reference link identifier of the target AP MLD. Specifically, the updated QoS feature element contains the first service start time as the service start time and the reference link identifier as the reference link identifier of the target AP MLD.

[0422] For example, the first implementation may include the following steps 1-5:

[0423] Step 1: The non-AP MLD sends a first request message to the current AP MLD, and the current AP MLD receives the first request message.

[0424] The first request information is used to request an SCS context transfer. In this application, there are no restrictions on the naming of the first request information; for example, it can be named SCS Context Transfer Request Information.

[0425] Step 2: The non-AP MLD sends the tenth message to the current AP MLD, and the current AP MLD receives the tenth message.

[0426] The tenth piece of information contains the TSF_offset between the current AP MLD and the target AP MLD, as well as the reference link identifier (link ID) of the target AP MLD.

[0427] Optionally, the tenth information can be carried in the link reconfiguration request frame or the fast transfer multilink establishment request frame.

[0428] Optionally, the non-AP MLD can obtain the TSF_offset between the current AP MLD and the target AP MLD in the following way: The non-AP MLD receives a management frame, such as a beacon frame or probe response frame, from the target AP MLD in the reference link and obtains the timestamp carried in the management frame; the timestamp in the beacon frame sent by the current AP MLD in the reference link is subtracted from the timestamp to obtain the TSF_offset between the current AP MLD and the target AP MLD. The reference link is described above and will not be repeated here.

[0429] Step 3: Before performing SCS context transfer, the current AP MLD updates the service start time and the service start time link identifier in the quality of service characteristic element.

[0430] Specifically, before performing SCS context transfer, the current AP MLD adds the second service start time and the TSF_offset between the current AP MLD and the target AP MLD to obtain the first service start time. That is, the first service start time is the sum of the second service start time and the TSF_offset between the current AP MLD and the target AP MLD. Further, the service start time in the quality of service feature element is updated to the first service start time, and the service start time link identifier in the quality of service feature element is updated to the reference link identifier of the target AP MLD.

[0431] Step 4: During the SCS context transition, the current AP MLD sends the updated service feature elements to the target AP MLD; correspondingly, the target AP MLD receives the updated service feature elements.

[0432] In the updated service quality feature element, the service start time is the first service start time, and the service start time link identifier is the reference link identifier of the target AP MLD. Thus, the target AP MLD obtains the first service start time and the target AP MLD's reference link identifier from the received updated service feature element.

[0433] Step 5: When the first service start time arrives, the non-AP MLD is scheduled in the link corresponding to the reference link identifier of the target AP MLD.

[0434] The second implementation: The non-AP MLD sends the TSF_offset between the current AP MLD and the target AP MLD, as well as the reference link identifier of the target AP MLD, to the target AP MLD. Before the SCS context transfer, the current AP MLD does not update the service start time and the service start time link identifier in the QoS feature element. In other words, the service start time in the QoS feature element remains the service start time negotiated when the non-AP MLD and the current AP MLD establish an SCS session; that is, the service start time in the QoS feature element is the second service start time. The service start time link identifier in the QoS feature element is the service start time link identifier negotiated when the non-AP MLD and the current AP MLD establish an SCS session; that is, the service start time link identifier is the link identifier corresponding to the current AP MLD. Then, during the SCS context transfer, the current AP MLD sends the QoS feature element to the target AP MLD, where the service start time is the second service start time, and the service start time link identifier is the link identifier of the current AP MLD. Accordingly, the target AP MLD receives the quality of service feature element and obtains the first service start time based on the second service start time in the quality of service feature element and the TSF_offset between the current AP MLD and the target AP MLD from the non-AP MLD.

[0435] For example, the second implementation may include the following steps 1-5:

[0436] Step 1: The non-AP MLD sends a first request message to the current AP MLD, and the current AP MLD receives the first request message.

[0437] The first request information is used to request an SCS context transfer. In this application, there are no restrictions on the naming of the first request information; for example, it can be named SCS Context Transfer Request Information.

[0438] Step 2: The non-AP MLD sends the eleventh message to the target AP MLD, and the target AP MLD receives the eleventh message.

[0439] The eleventh piece of information contains the TSF_offset between the current AP MLD and the target AP MLD, as well as the reference link identifier (link ID) of the target AP MLD.

[0440] Step 3: During the SCS context transition, the current AP MLD sends the service feature elements to the target AP MLD; correspondingly, the target AP MLD receives the service feature elements.

[0441] Specifically, the service start time in the quality of service (QoS) characteristic element is the service start time negotiated when the non-AP MLD and the current AP MLD establish an SCS session, and the service start time link identifier in the QoS characteristic element is the service start time link identifier negotiated when the non-AP MLD and the current AP MLD establish an SCS session. In other words, the service start time in the QoS characteristic element is the second service start time, and the service start time link identifier is the link identifier of the current AP MLD.

[0442] Step 4: The target AP MLD obtains the first service start time based on the eleventh information and the service start time in the quality of service feature element.

[0443] Specifically, the target AP MLD adds the service start time (second service start time) in the quality of service feature element and the TSF_offset between the current AP MLD and the target AP MLD to obtain the first service start time. That is, the first service start time is the sum of the second service start time and the TSF_offset between the current AP MLD and the target AP MLD.

[0444] Step 5: When the first service start time arrives, the non-AP MLD is scheduled in the link corresponding to the reference link identifier of the target AP MLD.

[0445] Unlike the two implementation methods described above, in the third implementation method, the TSF_offset between the current AP MLD and the target AP MLD is no longer provided by the non-AP MLD, but is determined by the target AP MLD based on the service feature element sent by the current AP MLD and the TSF value of the reference link corresponding to the current AP MLD. Furthermore, the target AP MLD obtains the first service start time based on its own determined TSF_offset between the current AP MLD and the target AP MLD, and the service start time in the service feature element. The reference link is described above and will not be repeated here.

[0446] For example, the third implementation may include the following steps 1-4:

[0447] Step 1: The non-AP MLD sends a first request message to the current AP MLD, and the current AP MLD receives the first request message.

[0448] The first request information is used to request an SCS context transfer. In this application, there are no restrictions on the naming of the first request information; for example, it can be named SCS Context Transfer Request Information.

[0449] Step 2: During SCS context transfer, the current AP MLD sends the Quality of Service (QoS) feature element and the TSF value (denoted as TSF_current) of the reference link corresponding to the current AP MLD to the target AP MLD. Correspondingly, the target AP MLD receives the QoS feature element and the TSF value of the reference link corresponding to the current AP MLD.

[0450] Specifically, the service start time in the quality of service (QoS) characteristic element is the service start time negotiated when the non-AP MLD and the current AP MLD establish an SCS session, and the service start time link identifier in the QoS characteristic element is the service start time link identifier negotiated when the non-AP MLD and the current AP MLD establish an SCS session. In other words, the service start time in the QoS characteristic element is the second service start time, and the service start time link identifier is the link identifier of the current AP MLD.

[0451] The reference link is described above and will not be repeated here.

[0452] Step 3: The target AP MLD obtains the first service start time based on the service start time in the service quality feature element and the TSF value of the reference link corresponding to the current AP MLD.

[0453] Specifically, the target AP MLD subtracts the TSF value (TSF_target) of the reference link corresponding to the current AP MLD from the TSF value (TSF_current) of the reference link corresponding to the current AP MLD to obtain the TSF_offset between the current AP MLD and the target AP MLD. Further, the target AP MLD adds the TSF_offset between the current AP MLD and the target AP MLD to the service start time in the service quality feature element to obtain the first service start time.

[0454] Step 4: When the first service start time arrives, the non-AP MLD is scheduled at the corresponding time, with the TSF of the reference link of the target AP MLD as a reference.

[0455] The reference link for the target AP MLD is the link corresponding to the link identifier at the service start time.

[0456] The corresponding time referenced to the TSF of the target AP MLD's reference link includes: the time obtained by taking the first service start time T0' as the first scheduling point, and using the minimum service interval (interval_min) and maximum service interval (interval_max) as constraints. For example, the first scheduling point is T0', the second scheduling time is any time within the time period T1, T1 = [T0' + interval_min, T0' + interval_max], the third scheduling time is any time within the time period T2, T2 = [T1 + interval_min, T1 + interval_max], ..., and so on, until the SCS flow service ends, and the scheduling ends.

[0457] Unlike the three implementation methods described above, in the fourth implementation method, the target AP MLD no longer obtains the first service time through SCS context transfer, but instead obtains the first service time from the non-AP MLD through SCS context renegotiation.

[0458] For example, the fourth implementation may include the following steps 1-3:

[0459] Step 1: The non-AP MLD sends a second request message to the target AP MLD, and the target AP MLD receives the second request message.

[0460] The second request information is used to request SCS context renegotiation. In this application, there are no restrictions on the naming of the second request information; for example, it can be named SCS context renegotiation request information.

[0461] Optionally, the second request information may be a link reconfiguration request frame carrying an SCS descriptor element, or a Fast Transfer Multi-Link Setup Request frame carrying an SCS descriptor element.

[0462] Step 2: The non-AP MLD updates the Quality of Service (QoS) feature elements and sends the updated QoS feature elements to the target AP MLD. The target AP MLD receives the updated QoS feature elements accordingly.

[0463] The non-AP MLD update of the quality of service feature elements includes: the non-AP MLD obtaining the TSF_offset between the current AP MLD and the target AP MLD; adding the TSF_offset and the service start time in the quality of service feature elements to obtain the first service start time; further, updating the service start time in the quality of service feature elements to the first service start time, and updating the service start time link identifier in the quality of service feature elements to the reference link identifier of the target AP MLD.

[0464] In the updated quality of service (QoS) feature elements, the service start time is the first service start time, and the service start time link identifier is the reference link identifier of the target AP MLD.

[0465] Step 3: When the first service start time arrives, the non-AP MLD is scheduled in the link corresponding to the reference link identifier of the target AP MLD.

[0466] The roaming process in any of Figures 2-13 above also includes an RSSI measurement process. The RSSI measurement process is used to obtain the link quality between the non-AP MLD and the AP MLD (e.g., the current AP MLD, a neighboring AP MLD). For example, before steps S203 and S303 above, the non-AP MLD performs an RSSI measurement process to obtain the link quality between itself and the neighboring AP MLD, then selects the neighboring AP MLD with better link quality as the target AP MLD, and roams to that target AP MLD. As another example, in steps S305 and S407 above, the non-AP MLD performs an RSSI measurement process to obtain the link signal quality between itself and the target AP MLD. If the link signal quality reaches a preset threshold, the non-AP MLD sends a roaming request frame to the target AP MLD.

[0467] The RSSI measurement process between the non-AP MLD and the neighboring AP MLD includes: the non-AP MLD sending a null data packet announcement (NDPA) to the neighboring AP MLD, with the receiving address of the NDPA being the AP MLD's MAC address. Correspondingly, the neighboring AP MLD receives the NDPA and, in response, sends both the NDPA and a null data packet (NDP) to the non-AP MLD. The NDPA sent by the neighboring AP MLD may carry the neighboring AP MLD's transmit power and its own TSF value. The neighboring AP MLD's transmit power refers to the transmit power used by the neighboring AP MLD to send the NDPA and NDP. This transmit power is the same as the transmit power used by the neighboring AP MLD when sending beacon frames. The neighboring AP MLD's own TSF value is used for time synchronization by the non-AP MLD.

[0468] One possible scenario is that the non-AP MLD knows the transmit power of the neighboring AP MLD through other means, such as obtaining AP transmit power information through over-the-DS probing. Furthermore, if the neighboring AP MLD maintains time synchronization with the current AP MLD, or if the non-AP MLD knows the TSF_offset between the neighboring AP MLD and the current AP MLD, the neighboring AP MLD will still send an NDPA carrying its transmit power and its own TSF value to the non-AP MLD if the neighboring AP MLD follows the RSSI measurement procedure described above. However, since the neighboring AP MLD's transmit power and its own TSF value carried in this NDPA are known information to the non-AP MLD, the neighboring AP MLD still sends the NDPA, reducing the utilization of air interface resources.

[0469] To improve the utilization of air interface resources, this application provides another communication method, which includes: a non-AP MLD sending NDPA to a neighboring AP MLD and sending a twelfth message, the twelfth message instructing the neighboring AP MLD to send NDP after receiving NDPA, or to send both NDPA and NDP. Correspondingly, the neighboring AP MLD receives NDPA and the twelfth message; in response to NDPA, it sends the information indicated by the twelfth message. Thus, when the non-AP MLD knows the transmission power of the neighboring AP MLD, and that the neighboring AP MLD and the current AP MLD maintain time synchronization, or knows the TSF_offset between the neighboring AP MLD and the current AP MLD, the non-AP MLD sending the twelfth message instructing the neighboring AP MLD to send NDP after receiving NDPA causes the neighboring AP MLD to stop sending NDPA after receiving it, thereby improving the utilization of air interface resources.

[0470] Figure 19 illustrates another communication method provided in an embodiment of this application, the method including S1901 and S1902:

[0471] S1901: The non-AP MLD sends an NDPA and a twelfth message to its neighboring AP MLD. Correspondingly, the neighboring AP MLD receives the NDPA and the twelfth message.

[0472] The NDPA contains information about the neighboring AP MLD, such as the MAC address of the neighboring AP MLD.

[0473] The twelfth piece of information is used to instruct the neighboring AP MLD to send an NDP after receiving an NDPA, or to send both an NDPA and an NDP. The NDP is an empty frame that does not carry data, but it contains a long training field for calculating channel information.

[0474] Optionally, if the non-AP MLD knows the transmit power of the neighboring AP MLD through other means, and the neighboring AP MLD and the current AP MLD maintain time synchronization; or, if the non-AP MLD knows the transmit power of the neighboring AP MLD through other means, and the non-AP MLD knows the TSF_offset between the neighboring AP MLD and the current AP MLD, the twelfth message instructs the neighboring AP MLD to send an NDP after receiving an NDPA. If the neighboring AP MLD and the current AP MLD are not in time synchronization, or the non-AP MLD cannot determine the TSF_offset between the neighboring AP MLD and the current AP MLD, the twelfth message instructs the neighboring AP MLD to send both an NDPA and an NDP after receiving an NDPA, and the neighboring AP MLD carries transmit power information and / or TSF information in the transmitted NDPA frame.

[0475] In this application, the twelfth message may directly or indirectly instruct the neighboring AP MLD to send an NDP after receiving an NDPA, or to send both an NDPA and an NDP.

[0476] In one example, the twelfth message instructs the neighboring AP MLD to send an NDP after receiving the NDPA, or to send both the NDPA and the NDP.

[0477] Optionally, in this example, the twelfth information can be carried in the required NDPA field, which is a field in the newly defined NDPA.

[0478] One possible design is that when the NDPA required field has the first value, the neighboring AP MLD is instructed to send both NDPA and NDP upon receiving the NDPA; when the NDPA required field has the second value, the neighboring AP MLD is instructed to send NDP upon receiving the NDPA. The first and second values ​​can be different; for example, the first value can be 1 and the second value 0, or the first value can be 0 and the second value 1.

[0479] In another example, the twelfth message indirectly instructs the neighboring AP MLD to send an NDP after receiving an NDPA by indicating whether it should send its own TSF and its own transmission power after receiving the NDPA. Specifically, if the twelfth message instructs the neighboring AP MLD not to send its own TSF and its own transmission power after receiving the NDPA, the neighboring AP MLD will send an NDP after receiving the NDPA; otherwise, the neighboring AP MLD will send both the NDPA and the NDP after receiving the NDPA.

[0480] Optionally, in this example, the twelfth information can be carried in the TX power required field and the TSF required field. The TX power required field and the TSF required field are newly defined fields in the NDPA. The TSF required field carries information from the twelfth information indicating whether the neighboring AP MLD should transmit its own TSF after receiving the NDPA, and the TX power required field carries information from the twelfth information indicating whether the neighboring AP MLD should transmit its own transmission power after receiving the NDPA.

[0481] One possible design is that the TSF required field has a third value, indicating that the neighboring AP MLD does not send its own TSF after receiving the NDPA; the TSF required field has a fourth value, indicating that the neighboring AP MLD sends its own TSF after receiving the NDPA. The third and fourth values ​​can be different, for example, the third value is 1 and the fourth value is 0; or the third value is 0 and the fourth value is 1.

[0482] In one possible design, the TX power required field takes the fifth value, indicating that the neighboring AP MLD will not transmit its own transmission power after receiving the NDPA; the TX power required field takes the sixth value, indicating that the neighboring AP MLD will transmit its own transmission power after receiving the NDPA. The fifth and sixth values ​​can be different; for example, the fifth value can be 1 and the sixth value 0; or the fifth value can be 0 and the sixth value 1.

[0483] Optionally, NDPA and the twelfth message can be carried in the same message or in different messages. For example, NDPA and the twelfth message can be carried in a newly defined NDPA.

[0484] S1902: In response to NDPA, the neighboring AP MLD sends NDP and NDPA to the non-AP MLD according to the twelfth information, or sends NDP. Accordingly, the non-AP MLD receives the information from the neighboring AP MLD.

[0485] In this scenario, the neighboring AP MLD responds to NDPA by sending NDP and NDPA to the non-AP MLD according to the twelfth information, or sending NDP includes: if the neighboring AP MLD responds to NDPA and, in accordance with the twelfth information instructing the neighboring AP MLD to send NDP after receiving NDPA, sending NDP to the non-AP MLD; or if, in accordance with the twelfth information instructing the neighboring AP MLD to send both NDP and NDPA after receiving NDPA, sending both NDPA and NDP to the non-AP MLD. The information from the neighboring AP MLD may include NDP and NDPA, or the information from the neighboring AP MLD may include only NDP.

[0486] The above primarily describes the solutions provided in this application from the perspective of interaction between various devices. It is understood that each device, such as an Access Point Multi-Link Device (AP MLD), including the current AP MLD, neighboring AP MLD, target AP MLD, and non-AP MLD, includes corresponding hardware structures and / or software modules to perform the aforementioned functions. Those skilled in the art should readily recognize that, based on the algorithm steps of the examples described in conjunction with the embodiments disclosed herein, this application can be implemented in hardware or a combination of hardware and computer software. Whether a function is executed in hardware or by computer software driving hardware depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0487] This application embodiment can group functional modules of access point multi-link devices, non-access point multi-link devices, etc., according to the above method examples. For example, each functional group can correspond to a functional module, or two or more functions can be integrated into one processing module. The integrated module can be implemented in hardware or as a software functional module. The grouping of modules in this application embodiment is illustrative and only represents one logical functional grouping; other grouping methods may be used in actual implementation.

[0488] Figure 20 shows a schematic diagram of a communication device 2000, which can be used to perform the functions of the access point multi-link device involved in the above embodiments, such as the function of the access point multi-link device in the method shown in Figure 7, or the function of the current access point multi-link device in the methods shown in Figures 11-13, or the function of the target access point multi-link device in Figure 18, or the function of the neighboring access point multi-link device in Figure 19. As one possible implementation, the communication device 2000 shown in Figure 20 includes: a processing unit 2001 and a transceiver unit 2002;

[0489] In one example, the processing unit 2001 is used to obtain first information, which indicates the type of SMD to which the AP MLD belongs, and the type of SMD is a centralized SMD or a distributed SMD; for example, the processing unit 2001 may support the communication device 2000 to execute S701.

[0490] Transceiver unit 2002: used to send first information; for example, transceiver unit 2002 may support communication device 2000 to execute S702.

[0491] Optionally, the transceiver unit 2002 is also used to send a second message, which indicates whether the location of the AP MLD is located at the edge of its SMD; for example, the transceiver unit 2002 may support the communication device 2000 to execute S704.

[0492] Optionally, when the AP MLD is a neighboring AP MLD of the non-AP MLD, the transceiver unit 2002 is also used to send third information, which is used to indicate whether the SMD to which the neighboring AP MLD belongs is the same as the SMD to which the current AP MLD of the non-AP MLD belongs; for example, the transceiver unit 2002 may support the communication device 2000 to execute S705.

[0493] Optionally, transceiver unit 2002 is also used to send a fourth message, which is used to provide information about neighboring AP MLDs for non-AP MLDs; for example, transceiver unit 2002 may support communication device 2000 to execute S706.

[0494] In another example, the AP MLD is the current AP MLD, and the processing unit 2001 is used to obtain the fifth information, which is used by the non-AP MLD to determine whether the clock of the current AP MLD is synchronized with the clock of the neighboring AP MLD; for example, the processing unit 2001 can support the communication device 2000 to execute S1101.

[0495] Transceiver unit 2002: used to send the fifth information; for example, transceiver unit 2002 may support communication device 2000 to execute S1102.

[0496] In another example, the AP MLD is the current AP MLD, and the processing unit 2001 is used to obtain the sixth information; the sixth information is used by the non-AP MLD to determine whether a new IP address needs to be requested when roaming from the current AP MLD to the target AP MLD. For example, the processing unit 2001 can support the communication device 2000 to execute S1201.

[0497] Transceiver unit 2002: is used to send the sixth information and the seventh information according to the sixth information. The seventh information is used by the non-AP MLD to determine whether data fronthaul is supported between the current AP MLD and the target AP MLD. For example, transceiver unit 2002 can support communication device 2000 to execute S1202.

[0498] In another example, the AP MLD is the current AP MLD, and the processing unit 2001 is used to obtain the eighth information and the ninth information; the eighth information is used to indicate whether to request data forwarding, and the ninth information is used to indicate whether to request context transmission; for example, the processing unit 2001 can support the communication device 2000 to execute S1301.

[0499] Transceiver unit 2002: used to send the eighth and ninth information; for example, transceiver unit 2002 can support communication device 2000 to execute S1302.

[0500] In another example, the AP MLD is the target AP MLD, and the processing unit 2001 is used to obtain the first service start time; the first service start time is obtained by calibrating the second service start time after the TSF_offset between the current AP MLD and the target AP MLD is calibrated; the second service start time is the service start time negotiated when the non-AP MLD establishes an SCS session with the current AP MLD; for example, the processing unit 2001 can support the communication device 2000 to execute S1801.

[0501] Transceiver unit 2002: Used to start scheduling non-AP MLD when the first service start time arrives; for example, transceiver unit 2002 can support communication device 2000 to execute S1802.

[0502] In another example, the AP MLD is a neighboring AP MLD, and the processing unit 2001 is used to send NDP and NDPA to the non-AP MLD according to the twelfth information in response to NDPA, or to send NDP; for example, the processing unit 2001 may support the communication device 2000 to perform S1902.

[0503] Transceiver unit 2002: Used to receive NDPA and twelfth information, the twelfth information being used to instruct the neighboring AP MLD to send NDP after receiving NDPA, or to send NDPA and NDP; for example, transceiver unit 2002 can support communication device 2000 to execute S1901.

[0504] The descriptions of the first to ninth information and the twelfth information can be referred to in the above method embodiments.

[0505] Specifically, all relevant content regarding each step of the AP MLD involved in the method embodiment shown in Figure 7, the current AP MLD involved in the method embodiments shown in Figures 11-13, the target AP MLD involved in the method embodiment shown in Figure 18, and the neighbor AP MLD involved in the method embodiment shown in Figure 19 can be referenced from the functional descriptions of the corresponding functional modules, and will not be repeated here. The communication device 2000 is used to execute the functions of the AP MLD in the method shown in Figure 7, the current AP MLD in the methods shown in Figures 11-13, the target AP MLD involved in the method embodiment shown in Figure 18, and the neighbor AP MLD involved in the method embodiment shown in Figure 19, thus achieving the same effect as the above-described communication method.

[0506] Figure 21 shows a schematic diagram of a communication device 2100, which can be used to perform the functions of a non-access point multilink device (non-AP MLD) involved in the above embodiments, such as the functions of the non-AP MLD in the methods shown in Figures 7, 11-13, 18, and 19. As one possible implementation, the communication device 2100 shown in Figure 21 includes: a transceiver unit 2101 and / or a processing unit 2102;

[0507] In one example, transceiver unit 2101 is used to receive first information; for example, transceiver unit 2101 may support communication device 2100 in executing S702.

[0508] Processing unit 2102: is used to execute the roaming process corresponding to the type of SMD indicated by the first information based on the first information; for example, processing unit 2102 may support communication device 2100 to execute S703.

[0509] Optionally, the transceiver unit 2101 is also configured to receive second information, which indicates whether the location of the AP MLD is located at the edge of its SMD; for example, the transceiver unit 2101 may support the communication device 2100 in executing S704.

[0510] Optionally, when the AP MLD is a neighboring AP MLD of the non-AP MLD, the transceiver unit 2101 is further configured to receive third information, which indicates whether the SMD to which the neighboring AP MLD belongs is the same as the SMD to which the current AP MLD of the non-AP MLD belongs; for example, the transceiver unit 2101 may support the communication device 2100 to execute S705.

[0511] Optionally, transceiver unit 2101 is also used to receive fourth information, which is used to provide information about neighboring AP MLDs for non-AP MLDs; for example, transceiver unit 2101 may support communication device 2100 to execute S706.

[0512] In another example, transceiver unit 2101 is used to receive the fifth information; for example, transceiver unit 2101 may support communication device 2100 in performing S1102.

[0513] In another example, transceiver unit 2101 is used to receive sixth and seventh information; the sixth information is used by the non-AP MLD to determine whether a new IP address needs to be requested when roaming from the current AP MLD to the target AP MLD, and the seventh information is used by the non-AP MLD to determine whether data forwarding is supported between the current AP MLD and the target AP MLD; for example, transceiver unit 2101 can support communication device 2100 to perform S1202.

[0514] In another example, transceiver unit 2101 is used to receive eighth information and ninth information; the eighth information is used to indicate whether to request data forwarding, and the ninth information is used to indicate whether to request context transmission; for example, transceiver unit 2101 may support communication device 2100 in performing S1302.

[0515] In another example, transceiver unit 2101 is used to send NDPA and twelfth information; the twelfth information is used to instruct the neighboring AP MLD to send NDP after receiving NDPA, or to send NDPA and NDP; for example, transceiver unit 2101 may support communication device 2100 to perform S1901.

[0516] In this example, transceiver unit 2101 is also used to receive information from neighboring AP MLD; the information of neighboring AP MLD includes NDP and NDPA, or the information of neighboring AP MLD includes NDP; for example, transceiver unit 2101 may support communication device 2100 to perform S1902.

[0517] The descriptions of the first to ninth and twelfth information can be found in the above method embodiments.

[0518] Specifically, all relevant content regarding each step of the non-AP MLD involved in the method embodiments shown in Figure 7, Figures 11-13, and Figure 19 can be referenced from the functional descriptions of the corresponding functional modules, and will not be repeated here. The communication device 2100 is used to execute the functions of the non-AP MLD in the method shown in Figure 7, the methods shown in Figures 11-13, and the method shown in Figure 19, thus achieving the same effect as the aforementioned communication methods.

[0519] The aforementioned processing unit can be a processor or a controller. It can implement or execute various exemplary logic blocks, modules, and circuits described in conjunction with the disclosure of this application. The processor can also be a combination that implements computing functions, such as a combination of one or more microprocessors, a combination of a DSP and a microprocessor, etc. The communication module can be a transceiver circuit or a communication interface, etc. The storage module can be a memory. When the processing module is a processor, the communication unit is a communication interface, and the storage module is a memory, the communication device 2000 and communication device 2100 involved in the embodiments of this application can be the communication device 2200 shown in FIG. 22. For example, the aforementioned AP MLD, current AP MLD, and non-AP MLD can adopt the composition structure shown in FIG. 22 or include the components shown in FIG. 22. FIG. 22 is a schematic diagram of the composition of a communication device 2200 provided in an embodiment of this application. As shown in FIG. 22, the communication device 2200 can include a processor 2201, a communication line 2202, and a communication interface 2203.

[0520] Furthermore, the communication device 2200 may also include a memory 2204. The processor 2201, the memory 2204, and the communication interface 2203 can be connected via a communication line 2202.

[0521] The processor 2201 can be a central processing unit (CPU), a network processor (NP), a digital signal processor (DSP), a microprocessor, a microcontroller, a programmable logic device (PLD), or any combination thereof. The processor 2201 can also be other communication devices with processing capabilities, such as circuits, devices, or software modules.

[0522] Communication line 2202 is used to transmit information between the components included in communication device 2200.

[0523] Communication interface 2203 is used for communication with other devices or other communication networks. These other communication networks can be Ethernet, radio access network (RAN), wireless local area network (WLAN), etc. Communication interface 2203 can be a radio frequency module, transceiver, or any communication device capable of communication. This application embodiment uses a radio frequency module as an example to illustrate communication interface 2203. The radio frequency module can include an antenna, radio frequency circuitry, etc., and the radio frequency circuitry can include a radio frequency integrated chip, a power amplifier, etc.

[0524] The memory 2204 is used to store instructions. These instructions can be computer programs.

[0525] The memory 2204 can be a read-only memory (ROM) or other type of static storage device that can store static information and / or instructions; it can also be a random access memory (RAM) or other type of dynamic storage device that can store information and / or instructions; it can also be an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disc storage, optical disc storage, magnetic disk storage medium or other magnetic storage device. Optical disc storage includes compressed optical discs, laser discs, optical discs, digital universal optical discs, Blu-ray discs, etc.

[0526] The memory 2204 can exist independently of the processor 2201 or be integrated with the processor 2201. The memory 2204 can be used to store instructions, program code, or some data. The memory 2204 can be located inside or outside the communication device 2200, without limitation. The processor 2201 is used to execute the instructions stored in the memory 2204 to implement the random access procedure preamble transmission method provided in the following embodiments of this application.

[0527] In one example, processor 2201 may include one or more CPUs, such as CPU0 and CPU1 in Figure 22.

[0528] As an optional implementation, the communication device 2200 may include multiple processors, for example, in addition to the processor 2201 in FIG22, it may also include a processor 2207 (not shown in FIG22).

[0529] As an optional implementation, the communication device 2200 also includes an output device 2205 and an input device 2206. The input device 2206 is a keyboard, mouse, microphone, or joystick, etc., and the output device 2205 is a display screen, speaker, etc.

[0530] The communication device 2200 may be a desktop computer, a portable computer, a web server, a mobile phone, a tablet computer, a wireless terminal device, an embedded device, a chip system, or a device with a similar structure to that shown in FIG22. Furthermore, the composition shown in FIG22 does not constitute a limitation on the communication device; in addition to the components shown in FIG22, the communication device may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0531] In this embodiment of the application, the chip system may be composed of chips or may include chips and other discrete devices.

[0532] This application also provides a computer-readable storage medium. All or part of the processes in the above method embodiments can be implemented by a computer program instructing related hardware. This program can be stored in the computer-readable storage medium, and when executed, it can include the processes of the above method embodiments. The computer-readable storage medium can be an access point multi-link device or a non-access point multi-link device of any of the foregoing embodiments, such as an internal storage unit including a data transmission end and / or a data receiving end, such as a hard disk or memory of the access point multi-link device or non-access point multi-link device. The computer-readable storage medium can also be an external storage device of the access point multi-link device or non-access point multi-link device, such as a pluggable hard disk, smart media card (SMC), secure digital (SD) card, flash card, etc., equipped on the access point multi-link device or non-access point multi-link device. Further, the computer-readable storage medium can include both internal storage units and external storage devices of the access point multi-link device or non-access point multi-link device. The aforementioned computer-readable storage medium is used to store the aforementioned computer program, as well as other programs and data required by the aforementioned access point multi-link device or non-access point multi-link device. The aforementioned computer-readable storage medium can also be used to temporarily store data that has been output or will be output.

[0533] It should be understood that the collection, storage, use, processing, transmission, provision, and disclosure of user personal information involved in the technical solution of this application all comply with relevant laws and regulations and do not violate public order and good morals. For example, in the technical solution of this application, the processing of user personal information is carried out with the user's authorization, and this will not be repeated hereafter.

[0534] The terms "first" and "second," etc., used in the specification, claims, and drawings of this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or apparatuses.

[0535] It should be understood that in this application, "at least one (item)" means one or more, "more than one" means two or more, "at least two (items)" means two or three or more, and "and / or" is used to describe the relationship between related objects, indicating that there can be three relationships. For example, "A and / or B" can mean: only A exists, only B exists, and A and B exist simultaneously, where A and B can be singular or plural. The character " / " generally indicates that the related objects before and after are in an "or" relationship. "At least one (item) of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one (item) of a, b, or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0536] It should be understood that in the embodiments of this application, "B corresponding to A" means that B is associated with A. For example, B can be determined based on A. It should also be understood that determining B based on A does not mean that B is determined solely based on A; B can also be determined based on A and / or other information. Furthermore, the term "connection" in the embodiments of this application refers to various connection methods, such as direct connection or indirect connection, to achieve communication between devices, and the embodiments of this application do not impose any limitations on this.

[0537] Unless otherwise specified, the term "transmission" in the embodiments of this application refers to bidirectional transmission, encompassing the actions of sending and / or receiving. Specifically, "transmission" in the embodiments of this application includes sending data, receiving data, or both sending and receiving data. In other words, data transmission here includes uplink and / or downlink data transmission. Data may include channels and / or signals; uplink data transmission refers to uplink channel and / or uplink signal transmission, and downlink data transmission refers to downlink channel and / or downlink signal transmission. The terms "network" and "system" in the embodiments of this application refer to the same concept; a communication system is a communication network.

[0538] Through the above description of the embodiments, those skilled in the art can clearly understand that, for the sake of convenience and brevity, only the grouping of the above functional modules is used as an example. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above.

[0539] In the several embodiments provided in this application, it should be understood that the disclosed communication devices and methods can be implemented in other ways. For example, the communication device embodiments described above are merely illustrative. For instance, the grouping of modules or units is only a logical functional grouping, and in actual implementation, there may be other grouping methods. For example, multiple units or components may be combined or integrated into another device, or some features may be ignored or not executed. Furthermore, the mutual coupling or direct coupling or communication connection shown or discussed may be through some interfaces, or indirect coupling or communication connection between devices or units, and may be electrical, mechanical, or other forms.

[0540] The units described as separate components may or may not be physically separate. A component shown as a unit can be one or more physical units; that is, it can be located in one place or distributed in multiple different locations. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0541] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0542] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a readable storage medium. Based on this understanding, the technical solutions of the embodiments of this application, essentially, or the parts that contribute to the prior art, or all or part of the technical solutions, can be embodied in the form of a software product. This software product is stored in a storage medium and includes several instructions to cause a device, such as a microcontroller, chip, or processor, to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media for storing program code, such as USB flash drives, portable hard drives, ROM, RAM, magnetic disks, or optical disks.

[0543] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A communication method characterized by comprising: The method is applied to access point multi-link devices, and the method includes: Obtain first information, which is used to indicate the type of Seamless Mobility Domain (SMD) to which the access point multilink device belongs, wherein the type of the Seamless Mobility Domain is a centralized Seamless Mobility Domain or a distributed Seamless Mobility Domain. Send the first message.

2. The method of claim 1, wherein, The roaming process of the centralized seamless mobile domain is the roaming process executed by non-AP MLD and AP MLD under the centralized SMD architecture. The centralized SMD architecture consists of non-collocated AP MLD (NC AP MLD) and multiple non-AP MLDs. The NC AP MLD includes one MLD upper MAC sublayer and multiple MLD lower MAC sublayers; The non-AP MLD is connected to the distributed system (DS) by associating with an MLD upper MAC sublayer.

3. The method according to claim 1 or 2, characterized in that, The roaming process of the distributed seamless mobile domain is the roaming process executed by non-AP MLD and AP MLD under the distributed SMD architecture. The distributed SMD architecture consists of multiple co-located AP MLDs and multiple non-AP MLDs. The non-AP MLD accesses the distributed system (DS) through the MAC SAP associated with its associated AP MLD.

4. The method according to any one of claims 1-3, characterized in that, The method further includes: Send a fourth message, which is used to provide the non-access point multilink device with information about the neighboring access point multilink devices of the non-access point multilink device; the fourth message includes at least one of a robust secure network sub-element, a robust secure network extension sub-element, a supported rate and basic service set member selector sub-element, and an extended supported rate and basic service set member selector sub-element.

5. The method of claim 1, wherein, The method further includes: Send a second message, which indicates whether the location of the access point multilink device is located at the edge of the seamless mobility domain.

6. The method according to any one of claims 1 to 5, characterized in that, When the access point multilink device is a neighboring access point multilink device of a non-access point multilink device, the method further includes: Send a third message, which indicates whether the seamless mobility domain is the same as the seamless mobility domain to which the current access point multilink device of the non-access point multilink device belongs.

7. The method according to any one of claims 1-6, characterized in that, The first information is carried in any one of a beacon frame, a probe request frame, a neighbor report element, or a newly defined seamless mobility domain element; the newly defined seamless mobility domain element is used to carry relevant information about the seamless mobility domain.

8. The method according to any one of claims 5-7, characterized in that, The second information is carried in any one of the extended service set report element, the mobile domain element, or the newly defined seamless mobile domain element.

9. A communication method characterized by comprising: The method is applied to non-access point multi-link devices, and the method includes: Receive first information, the first information being used to indicate the type of seamless mobility domain to which the access point multilink device belongs, the type of seamless mobility domain being either a centralized seamless mobility domain or a distributed seamless mobility domain; Based on the first information, the roaming process corresponding to the type of the seamless mobile domain is executed.

10. The method of claim 9, wherein, The roaming process of the centralized seamless mobile domain is the roaming process executed by non-AP MLD and AP MLD under the centralized SMD architecture. The centralized SMD architecture consists of non-collocated AP MLD (NC AP MLD) and multiple non-AP MLDs. The NC AP MLD includes one MLD upper MAC sublayer and multiple MLD lower MAC sublayers; The non-AP MLD is connected to the distributed system (DS) by associating with an MLD upper MAC sublayer.

11. The method according to claim 9 or 10, characterized in that, The roaming process of the distributed seamless mobile domain is the roaming process executed by non-AP MLD and AP MLD under the distributed SMD architecture. The distributed SMD architecture consists of multiple co-located AP MLDs and multiple non-AP MLDs. The non-AP MLD accesses the distributed system (DS) through the MAC SAP associated with its associated AP MLD.

12. The method according to any one of claims 9-11, characterized in that, The method further includes: Receive fourth information, the fourth information being used to provide the non-access point multilink device with information about the neighboring access point multilink devices of the non-access point multilink device; the fourth information includes at least one of a robust secure network sub-element, a robust secure network extension sub-element, a supported rate and basic service set member selector sub-element, and an extended supported rate and basic service set member selector sub-element.

13. The method according to claim 9, characterized in that, When the type of the seamless mobility domain is the centralized seamless mobility domain, the roaming process corresponding to the type of the seamless mobility domain is the centralized seamless mobility domain roaming process; When the seamless mobility domain type is the distributed seamless mobility domain, the roaming process corresponding to the seamless mobility domain type is the distributed seamless mobility domain roaming process.

14. The method according to any one of claims 9 to 13, characterized in that, The method further includes: Receive second information, which indicates whether the location of the access point multilink device is located at the edge of the seamless mobility domain.

15. The method according to any one of claims 9 to 14, characterized in that, When the access point multilink device is a neighboring access point multilink device of the non-access point multilink device, the method further includes: Receive third information, which is used to indicate whether the seamless mobility domain is the same as the seamless mobility domain to which the current access point multilink device belongs.

16. The method according to any one of claims 9-15, characterized in that, The first information is carried in any one of a beacon frame, a probe request frame, a neighbor report element, or a newly defined seamless mobility domain element; the newly defined seamless mobility domain element is used to carry relevant information about the seamless mobility domain.

17. The method according to any one of claims 9-16, characterized in that, The second information is carried in any one of the extended service set report element, the mobile domain element, or the seamless mobile domain element.

18. A method of communication, comprising: The method is applied to a multi-link device at the current access point, and the method includes: The fifth piece of information is obtained, which is used by the non-access point multi-link device to determine whether the clock of the current access point multi-link device is synchronized with the clock of the neighboring access point multi-link devices; Send the fifth message.

19. The method according to claim 18, characterized in that, If the seamless mobility domain to which the current access point multilink device belongs is the same as the seamless mobility domain to which the neighboring access point multilink device belongs, the fifth information indicates that the clocks of each access point multilink device in the seamless mobility domain to which the current access point multilink device belongs are synchronized.

20. The method according to claim 18, characterized in that, The fifth piece of information indicates whether the clock of the current access point multi-link device is synchronized with the clock of the neighboring access point multi-link device.

21. A method of communication, comprising: The method is applied to non-access point multi-link devices, and the method includes: The fifth information is received, which is used by the non-access point multi-link device to determine whether the clock of the current access point multi-link device is synchronized with the clock of the neighboring access point multi-link devices.

22. The method according to claim 21, characterized in that, If the seamless mobility domain to which the current access point multilink device belongs is the same as the seamless mobility domain to which the neighboring access point multilink device belongs, the fifth information indicates that the clocks of each access point multilink device in the seamless mobility domain to which the current access point multilink device belongs are synchronized.

23. The method according to claim 21, characterized in that, The fifth piece of information indicates whether the clock of the current access point multi-link device is synchronized with the clock of the neighboring access point multi-link device.

24. A method of communication, comprising: The method is applied to a multi-link device at a target access point, and the method includes: Obtain the first service start time; the first service start time is obtained by calibrating the second service start time after the time synchronization function offset between the current access point multi-link device and the target access point multi-link device, and the second service start time is the service start time negotiated when the non-access point multi-link device and the current access point multi-link device establish a flow classification service session; When the first service start time arrives, the scheduling of the non-access point link device begins.

25. The method of claim 24, wherein, The step of obtaining the first service start time includes: obtaining the first service start time, and obtaining the reference link identifier of the target access point multi-link device.

26. The method of claim 24 or 25, wherein, The time for obtaining the first service start time includes: Receive the second service start time and the time synchronization function value of the reference link corresponding to the current access point multi-link device; the reference link is the link corresponding to the service start time link identifier negotiated when the non-access point multi-link device and the current access point multi-link device establish a flow classification service session; The first service start time is obtained based on the second service start time and the time synchronization function value of the reference link corresponding to the current access point multi-link device.

27. The method of any one of claims 24-26, wherein, The first service start time is obtained by calibrating the second service start time using the time synchronization function offset between the current access point multi-link device and the target access point multi-link device, including: The first service start time is obtained by adding the second service start time to the time synchronization function offset between the current access point multilink device and the target access point multilink device.

28. The method of any one of claims 24-27, wherein, The time synchronization function offset between the current access point multi-link device and the target access point multi-link device is obtained by subtracting the time synchronization function value of the current access point multi-link device corresponding to the reference link from the time synchronization function value of the target access point multi-link device corresponding to the reference link.

29. A communications device, characterized by The communication device includes a processor, the processor being configured to execute a computer program or instructions that cause the communication method as described in any one of claims 1-8 to be executed, or cause the communication method as described in any one of claims 9-17 to be executed, or cause the communication method as described in any one of claims 18-20 to be executed, or cause the communication method as described in any one of claims 21-23 to be executed, or cause the communication method as described in any one of claims 24-28 to be executed.

30. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions that, when executed on a computer, cause the communication method as described in any one of claims 1-8 to be executed, or cause the communication method as described in any one of claims 9-17 to be executed, or cause the communication method as described in any one of claims 18-20 to be executed, or cause the communication method as described in any one of claims 21-23 to be executed, or cause the communication method as described in any one of claims 24-28 to be executed.

31. A computer program product, characterised in that, The computer program product includes computer instructions that, when some or all of the computer instructions are executed, cause the communication method as described in any one of claims 1-8 to be executed, or cause the communication method as described in any one of claims 9-17 to be executed, or cause the communication method as described in any one of claims 18-20 to be executed, or cause the communication method as described in any one of claims 21-23 to be executed, or cause the communication method as described in any one of claims 24-28 to be executed.

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