Reliable frame transmission scheme for multi-link devices

Abstract

In implementations of the present disclosure, a reliable frame transmission scheme for a multi-link device is provided, and a method for transmitting a broadcast frame (BC) or a multicast (MC) frame is provided. A method includes obtaining a BC frame or an MC frame. Further, a plurality of links used by an access point (AP) multi-link device (MLD) are determined. A primary link is then selected from the plurality of links based on usage conditions of the plurality of links. The BC frame or the MC frame is converted to a unicast frame for the primary link. Next, the unicast frame is transmitted to the site MLD in the set of sites by using the primary link. The implementation of the invention can reduce the time waste of station MLD, the waste of channel resources and the serious problem of dynamic multicast optimization at the station side.

Description

Technical Field

[0001] Embodiments of the present disclosure relate to a reliable frame transmission scheme for multi-link devices. Background Art

[0002] Multi-link operation (MLO) is a major medium access control (MAC) function introduced in Wi-Fi 7. It enables a device to exchange frames over multiple links. MLO enables a non-access point (AP) multi-link device (MLD) to discover, authenticate, associate, and configure multiple links with an AP MLD. Each link can implement channel access and frame exchange between the non-AP MLD and the AP MLD based on the supported capabilities exchanged during the association.

[0003] In networking and telecommunications, a broadcast (BC) frame or a multicast (MC) frame refers to a type of data frame used in network communication protocols for efficiently transmitting data to multiple recipients simultaneously. This is typically used in situations where the same information needs to be sent to multiple destinations, such as broadcasting data to all devices on a network or multicasting data to a specific group of devices. An AP MLD can send BC frames or MC frames to a non-AP MLD. Brief Description of the Drawings

[0004] When read in conjunction with the drawings, the implementation of the present disclosure can be understood from the following detailed description. In accordance with standard industry practice, the various features are not drawn to scale. In fact, for clarity of discussion, the dimensions of the various features may be increased or decreased arbitrarily. Some examples of the present disclosure are described with reference to the following drawings.

[0005] Figure 1 A block diagram showing an example environment in which a reference implementation of the present disclosure can be implemented;

[0006] Figure 2 An example of primary link selection according to an implementation of the present disclosure;

[0007] Figure 3 Another example of primary link selection according to an implementation of the present disclosure;

[0008] Figure 4 An example of sending a BC frame or an MC frame according to an implementation of the present disclosure;

[0009] Figure 5A An example of the target beacon transmission time (TBTT) information field format according to an implementation of the present disclosure;

[0010] Figure 5B An example of the BSS parameter sub-field format according to an implementation of the present disclosure;

[0011] Figure 5CShows an example of the MLD parameter subfield format implemented according to the present disclosure;

[0012] Figure 6 Shows an example of sending a BC frame or an MC frame implemented according to the present disclosure;

[0013] Figure 7 Shows a flowchart of an example method for sending a broadcast frame or a multicast frame implemented according to the present disclosure; and

[0014] Figure 8 Shows an example access point multi-link device implemented according to the present disclosure.

[0015] Specific implementation

[0016] As described above, the AP MLD can send BC frames or MC frames to non-AP MLDs. If a station connected to the AP MLD enters the power-saving state, BC frames or MC frames are sent at the Delivery Traffic Indication Map (DTIM) time. The AP MLD will send them on each link with the same sequence number because each link may have non-MLD stations. In this case, there are many problems.

[0017] For example, the station MLD will receive multiple (equal to the number of MLO links) identical BC frames or MC frames. When there are many more station MLDs than non-MLD stations, this is a waste of time for the station MLD and also a waste of channel resources. In addition, traditional Dynamic Multicast Optimization (DMO, this function will dynamically convert a multicast stream into a unicast stream) is no longer applicable to Wi-Fi 7 MLD. If the multicast frame is converted into a unicast frame for each station on all links, the station MLD will receive multiple unicast frames with the same content from different links, which may cause serious problems and higher channel utilization on the station side.

[0018] In addition, sending BC frames or MC frames needs to meet some latency defects and security issues. Since the Group Temporal Key (GTK) between MLD links is different, and the key encryption type needs to be compatible with the lowest-level station connected to the same Basic Service Set (BSS), any GTK update process or security compatibility issue will affect the reliability of BC / MC.

[0019] Accordingly, the implementation of the present disclosure proposes a solution for reliably sending broadcast frames or multicast frames to a station MLD device. According to the implementation of the present disclosure, the AP MLD obtains a BC frame or an MC frame. The AP MLD also determines a plurality of links used by the AP MLD, where the plurality of links are linked between the AP MLD and a set of stations including the station MLD. Then, the AP MLD selects a primary link from the plurality of links based on the usage conditions of the plurality of links, and the AP MLD further converts the obtained BC frame or the obtained MC frame into a unicast frame for the primary link. Then, the AP MLD uses the primary link to send the unicast frame to the station MLD in the set of stations.

[0020] The AP MLD can send the BC frame or the MC frame via the primary link by converting the BC frame or the MC frame into a unicast frame and discarding the BC frame or the MC frame on other links. Accordingly, the station MLD receives a unicast frame corresponding to one BC frame or one MC frame, rather than receiving multiple identical BC frames or MC frames from different links, or multiple unicast frames with the same content. Therefore, this operation avoids the time waste and channel resource waste in the transmission and reception of the STA MLD when there are much more MLD STAs than non-MLD STAs. This operation also avoids causing serious problems and higher channel utilization on the station side.

[0021] Other advantages of the implementation of the present disclosure will be described below with reference to reference implementations. The following references Figures 1 to 8 are used to illustrate the basic principles and several reference implementations of the present disclosure.

[0022] Figure 1 shows a block diagram of an example environment in which a reference implementation of the present disclosure can be implemented. In Figure 1 the example environment 100, the AP MLD 102 communicates with a set of stations 112 via a plurality of links such as link 110-1, …, link 110-N, where N is an integer. The AP MLD 102 includes a plurality of APs, for example, AP 104-1, …, AP 104-N, and each AP establishes a link to connect to some stations in the set of stations 112, and the set of stations 112 includes the station MLD and / or traditional stations without MLO capabilities.

[0023] In some implementations, the multiple links can be two links. For example, one link is related to 2.4 GHz, while the other link is related to 5 GHz. Thus, the AP MLD 102 can communicate with the station MLD via the 2.4 GHz link and the 5 GHz link. In addition, some legacy stations can communicate with the AP MLD 102 via the 2.4 GHz link or the 5 GHz link. In some implementations, the multiple links can be three links. For example, the first link is related to 2.4 GHz, the second link is related to 5 GHz, and the third link is related to 6 GHz. Thus, the station MLD can communicate with the AP MLD 102 via two or three of the 2.4 GHz link, the 5 GHz link, and the 6 GHz links. In addition, some legacy stations can communicate with the AP MLD 102 via the 2.4 GHz link, the 5 GHz link, or the 6 GHz link.

[0024] The station set 112 includes the station MLD 114, the station MLD 116… and the station 118. The station MLD 114 and the station MLD 116 can communicate with the AP MLD via multiple links. The multiple links can be a part of or all of the multiple links. The station 118 is a legacy station and does not have MLO capabilities, so it communicates with the AP MLD 102 via one of the multiple links.

[0025] In an implementation of the present disclosure, DMO can be used by the AP MLD to send a BC frame or an MC frame to a station set. When DMO is used, the BC frame or the MC frame will be converted into a unicast frame. If the AP MLD 102 determines to send a BC frame or an MC frame using DMO, then in order to prevent the station MLD from receiving multiple unicast frames with the same content from different links, a primary link is selected from the multiple links. The selection of the primary link will be described with reference to Figure 2 and Figure 3 If DMO is used by the AP MLD 102, the selected primary link is used to send the BC frame or the MC frame 106, and the AP MLD will discard the BC frame or the MC frame on other links. As Figure 1 shown, the link 110-N is selected as the primary link. Thus, the BC frame or the MC frame 106 is sent by the AP 104-N corresponding to the primary link 110-N.

[0026] During transmission, the AP 104-N converts the BC frame or MC frame 106 into a unicast frame 108. Then, the unicast frame 108 is transmitted on the primary link 110-N to the set of stations 112. Other links will not transmit BC frames or MC frames. In this case, the station MLD communicating with the APMLD 102 can receive only the unicast frames generated from the BC frames or MC frames from the primary link, and will not receive multiple unicast frames generated from the BC frames or MC frames from other links, which avoids the waste of time in sending and receiving and the waste of channel resources for the station MLD. For the station MLD not connected to the primary link or a legacy station, the AP MLD 102 can send the BC frame or MC frame to the station MLD or non-MLD station via other links. For example, the AP MLD 102 can convert the BC frame or MC frame into a unicast frame and send the unicast frame to the station MLD or non-MLD station not connected to the primary link via other links.

[0027] As described above, when the AP MLD uses DMO to send BC frames or MC frames, it is necessary to select the primary link and use the primary link to send BC frames and MC frames in an efficient and reliable manner. The appropriate primary link for the MLD and non-MLD fixed network topologies can be selected dynamically. For the station MLD with multiple links connected to the AP MLD, the AP MLD should select only one link for DMO to the station MLD and discard the BC frames or MC frames on other links.

[0028] The above describes that the AP MLD 102 can use DMO to send BC frames or MC frames. In addition, the AP MLD 102 can send BC frames or MC frames with the same content via multiple links in the legacy mode. The multiple links have different Delivery Traffic Indication Message (DTIM) periods. For example, the DTIM period of link 1 is 2 and the DTIM period of link 2 is 3. The station MLD can be of the multi-link single-radio (MLSR) type. Therefore, the MLST station MLD can switch between different links. In this case, if the MLST station MLD switches to another link before the DTIM time of the current link, the MLST station MLD may lose the BC frame or MC frame. To avoid the MLSR type of station MLD losing the BC frame or MC frame, the AP MLD 102 can determine the least common multiple of the multiple DTIM periods of the multiple links as the aligned DTIM period; and send the BC frame or MC frame at the aligned DTIM period.

[0029] In some implementations, to ensure the security of BC frames or MC frames, the AP MLD 102 may use different group keys to encrypt the BC frames or MC frames of the station MLD and non-MLD stations. In some implementations, to ensure the reliability of BC frames or MC frames, the AP MLD 102 and the station MLD may use the operation of the on-channel tunnel (OCT). In this case, multiple BC frames or MC frames for multiple links may be sent through one of the multiple links, and multiple BC frames or MC frames are decrypted with different group keys for different links.

[0030] For example, Figure 2 FIG. 200 shows an example of the primary link selection implemented according to the present disclosure. In Figure 2 FIG. 200, there is an AP MLD 202, which has two APs, and two station MLDs 208 and 214, and each station MLD includes two stations. The AP MLD 202 communicates with the station MLD 208 and the station MLD 214 through two links. For example, the AP 204 in the AP MLD 202 communicates with the station 210 in the station MLD 208 and the station 216 in the station MLD 214 through the first link, and the AP 206 in the AP MLD 202 communicates with the station 212 in the station MLD 208 and the station 218 in the station MLD 214 through the second link. When the AP MLD 202 and the station MLDs 108 and 214 perform DMO, one link is selected as the primary link.

[0031] The selection of the primary link is based on the usage of multiple links. In some implementations, the selection of the primary link is based on the processing capacity of the AP corresponding to the link. For example, the strongest CPU can execute DMO quickly. Therefore, the link corresponding to the AP with the strongest CPU is used as the primary link. As Figure 2 shown in FIG. 200, the processing capacity of the AP 206 is stronger than that of the AP 204. Therefore, the link of the AP 206 is selected for DMO, and vice versa.

[0032] In some implementations, the selection of the primary link is based on the health status of the link. For example, the healthiest link is selected as the primary link for performing DMO. The health status of the link is related to channel utilization, background noise (NF), transmission, and other factors. Therefore, the healthiest link can be selected based on the above factors. For example, as Figure 2 shown in FIG. 200, if the health status of the link of the AP 206 is better than that of the AP 204, the link of the AP 206 is used as the primary link for DMO, and vice versa.

[0033] In some implementations, when the AP MLD selects the primary link, the processing capabilities of the APs corresponding to the links and the health status of the links are considered simultaneously. For example, the healthiest link corresponding to the strongest CPU is used as the primary link. In some implementations, the selection of the primary link can be based on the traffic volume and air quality of a link. The above examples are used to describe the present disclosure and are not limitations on the present disclosure.

[0034] In addition, a common link among all the station MLDs can be selected as the primary link. For example, the AP can determine the number of station MLDs linked to each of the multiple links; then select the primary link from the multiple links based on the number of station MLDs. For example, the link with the largest number of station MLDs is used as the primary link. Figure 3 Another example 300 of primary link selection according to an implementation of the present disclosure is shown. In Figure 3 this example, the AP 302 has three APs, for example, AP 304, AP 306, and AP 308, and these three APs have three links. As Figure 3 shown, the station MLD 310 has three stations 312, 314, and 316, the station MLD 318 has two stations 320 and 322, and the station MLD 324 has two stations 326 and 328. The AP 304 in the AP MLD 302 communicates with the station 312 in the station MLD 310 and the station 326 in the station MLD 324 through the first link. The AP 306 in the AP MLD 302 communicates with the station 314 in the station MLD 310, the station 320 in the station MLD 318, and the station 328 in the station MLD 324 through the second link. The AP 308 in the AP MLD 302 communicates with the station 316 in the station MLD 310 and the station 322 in the station MLD 318 through the third link. The number of station MLDs connected to the second link is 3, and the number of station MLDs connected to the first link or the third link is 2. Therefore, the number of station MLDs connected to the second link is the largest number. The second link associated with the AP 306 is used as the primary link.

[0035] In some cases, the MLD of a multi-link single-radio (MLSR) type station may lose BC / MC frames. For example, when the MLD of an MLST station switches between different links, if the switch causes the MLD of the MLST station to miss the DTIM period, the MLD of the MLST station may lose BC / MC frames. To avoid the above situation, the DTIM periods for sending BC / MC frames on multiple links can be aligned. In addition, the beacon TBTTs of each link can be aligned. The corresponding DTIM periods for Link 1, …, and Link n are D1, …, and Dn. The aligned DTIM period for sending BC / MC frames is defined as the least common multiple of the DTIM periods of each link. For example, the aligned DTIM period is the least common multiple of D1, …, Dn. After determining the aligned DTIM period, the AP sends BC / MC frames at the aligned DTIM time. In this case, regardless of which link among the multiple links the MLST station MLD switches to, it will receive BC / MC frames at the aligned DTIM time.

[0036] Figure 4 An example 400 for sending a BC frame or an MC frame according to an implementation of the present disclosure is shown. In Figure 4 this case, the AP MLD communicates with a set of stations including the station MLD via three links, such as Link 1, Link 2, and Link 3. The beacon TBTTs of each link can be aligned. The DTIM period of Link 1 is 1, the DTIM period of Link 2 is 2, and the DTIM period of Link 3 is 3. The least common multiple of the DTIM periods of the three links is 6. Therefore, the aligned DTIM period is 6. The AP MLD can send BC / MC frames at the aligned DTIM time. In this case, the MLST station MLD can receive BC frames or MC frames regardless of the switching operation of the MLST station MLD.

[0037] In the present disclosure, the security issues of BC frames or MC frames are also addressed. There are some deficiencies and security issues with BC / MC keys because BC / MC frames must be sent at the basic rate, and the key encryption type needs to be compatible with the lowest-level stations connected to the same basic service set (BSS). This means that even if the AP BSS has extremely high throughput (EHT, also known as 11be Wi-Fi 7) capabilities, its unicast keys can be encrypted using Wi-Fi Protected Access 3 (WPA3, which is an encryption mode), but its BC / MC keys can still be Wired Equivalent Privacy (WEP, which is an encryption mode) using Rivest Cipher 4 (RC4). To avoid the above problems, the AP BSS distributes two group keys to the MLD stations and traditional stations without MLO.

[0038] In the present disclosure, the group key is separated according to the MLD site and the legacy site, referred to as the MLD group key and the legacy group key. The group key is generated with a random value in HOSTAPD (which is a userspace daemon for the access point and the authentication server), and will be sent from the AP to the site via the Extensible Authentication Protocol in the IEEE 802.1X Extensible Authentication Protocol over LAN (EAPOL) 3 (3 indicates the third EAPOL frame in the key exchange process) frame. Two group keys are generated based on the peer client and whether it has an EHT element. If the site does not have EHT capabilities, the process generates a legacy group key for each radio, and if the site has EHT capabilities, it will generate an MLD group key with AES_GCM_256 to maintain high security and fast group keys when sending BC frames or MC frames across MLD links, and this MLD group key will be shared among all MLD links. The BC frame or MC frame can be sent in one of the MLD links with robust encryption and high speed.

[0039] Next, these two group keys will be set to the driver, and when a BC frame or MC frame comes from the upper layer application and is sent to the driver, the driver will encrypt the BC frame or MC frame with the legacy group key and the MLD group key respectively and send it to the radio interface. As described above, the driver will select one of the MLD links as the primary link and then use the selected primary link to send the encrypted BC frame or MC frame.

[0040] The driver will send two copies of the BC frame or MC frame (because on the driver side, it cannot calculate whether it is EHT or non-EHT, because when the destination address (DA) mac address indicates BC / MC, the driver will use the group key), but for MLD, all MLD links share one group key. One of the MLD links can be selected as the primary link for sending BC / MC frames encrypted at the highest rate and with the group key to improve the reliability of MLD BC / MC.

[0041] In addition, the present disclosure can utilize the Operation on Channel Tunnels (OCT) to guarantee BC / MC traffic between MLD links. The BC / MC keys are different between MLD links; for example, the Group Temporal Key (GTK) and GTK update process between MLD links are dynamic, so there may be an inconsistent state for some time during the MLD GTK update. The MLD active link may not be able to decode the BC / MC frame with its own old GTK (sometimes, the active link may be the primary link, and re-association may introduce traffic delay), so the MLD OCT for BC / MC in the MLD link is used.

[0042] To use the MLD OCT, the sub-fields recommended by the OCT need to be set. Figure 5AAn example 500A of the TBTT information field format according to an implementation of the present disclosure is shown. As Figure 5A shown, the TBTT information field includes a BSS parameter sub-field. Figure 5B An example 500B of the BSS parameter sub-field format according to an implementation of the present disclosure is shown. As Figure 5B shown, the BSS parameter sub-field includes an OCT recommendation sub-field. Thus, for MLD links belonging to the same AP MLD in a reduced neighbor report (RNR) information element (IE), the sub-field of the OCT recommendation in at least one TBTT information is equal to 1. For example, for an MLD X having three MLD links 1, 2, and 3, the transmit (TX) beacon frame on the 2.4G link 1 carries an RNR IE with OCT support on the 5G link 2 and the 6G link 3, the TX beacon frame in the 5G link 2 carries an RNR IE with OCT support on the 2.4G link 1 and the 6G link 3, and the TX beacon frame on the 6G link 3 carries an RNR-IE with OCT support on the 2.4G link 1 and the 5G link 2. In addition, the TBTT information field further includes an MLD parameter sub-field. Figure 5C An example 500C of the MLD parameter sub-field format according to an implementation of the present disclosure is shown. The MLD parameter sub-field includes an AP MLD identifier (ID), a link ID, etc.

[0043] Figure 6 An example 600 for transmitting a BC frame or an MC frame according to an implementation of the present disclosure is shown. In Figure 6In it, the AP can broadcast the OCT capabilities in the RNR IE of the beacon frame in Link 1 and / or Link 2. Then, the AP multicast listener discovery (MLD) local media access control address (LMAC) Link 1 will send the first BC frame or MC frame B1 encrypted with key B1 (GTK1). Then, the AP MLD LMAC Link 2 will forward the second BC frame or MC frame B2 encrypted with key -B2 (GTK 2) to Link 1 through the internal AP MLD unified media access control (UMAC). The AP MLD LMAC Link 1 will send B2 encrypted with key -B2 together with B1. Then, the station MLD can receive B1 and B2. Next, the station MLD LMAC Link 1 can then receive B1 and B2, and decrypt B1 using the key -B1 on the station MLD-LMAC Link 1. The station MLD LMAC Link 1 forwards B2 internally to Link 2 through the station MLD UMAC. The station MLD LMAC Link 2 will decrypt B2 using the key -B2. By using OCT, a single MAC protocol data unit (MPDU) can be sent in one OCT action frame, and the MPDU of one band can be sent on another band through OCT. In the present disclosure, OCT is utilized to carry BC / MC frames. Additionally, as Figure 6 shown, the AP MLDLMAC Link 2 can send B2 and B1 in a similar manner.

[0044] Figure 7 FIG. shows a flowchart of an example method for sending a broadcast frame or a multicast frame according to an implementation of the present disclosure, and method 700 is performed by the AP MLD. At 702, the AP MLD obtains a broadcast (BC) frame or a multicast (MC) frame. For example, the AP MLD102 can generate a BC frame or an MC frame. The BC frame is used to send data to all devices in a network segment. The multicast frame is used to send data to a specific group of devices in a network segment. For the BC frame or the MC frame, if some stations enter the power-saving state, they are sent at the DTIM time.

[0045] At 704, the AP MLD determines a plurality of links used by the AP MLD, and the plurality of links are linked between the AP MLD and a set of stations including the station MLD. For example, the AP MLD102 determines that there are a plurality of links between the AP MLD 102 and the set of stations 112. In some implementations, the AP MLD can communicate with the set of stations 112 through two links; for example, Link 1 involves 2.4 GHz and Link 2 involves 5 GHz. In some implementations, the AP MLD can communicate with the set of stations through three links. For example, Link 1 involves 2.4 GHz, Link 2 involves 5 GHz, and Link 3 involves 6 GHz. The AP MLD 202 can determine the plurality of links based on the AP included in the AP MLD.

[0046] At 706, the AP MLD determines the primary link from among multiple links based on the usage conditions of the multiple links. For example, the AP MLD 102 selects the primary link 110-N from among the multiple links according to the usage conditions of the multiple links. In some implementations, the usage conditions of the multiple links include the processing capabilities of the APs in the AP MLD corresponding to the multiple links. For example, the CPU can be used to represent the processing capabilities. Thus, the link corresponding to the AP with the strongest CPU is used as the primary link. In some implementations, the usage conditions of the multiple links include the health status of the multiple links. Thus, the health status of the multiple links can be used to select the primary link. For example, the healthiest link is selected as the primary link. The health status of the multiple links can be determined by using factors such as channel utilization, NF, retransmissions, and others. Additionally, the usage conditions of the multiple links can include the processing capabilities of the APs in the AP MLD corresponding to the multiple links and the health status of the multiple links. Thus, the primary link can be selected based on the processing capabilities of the APs in the AP MLD corresponding to the multiple links and the health status of the multiple links. Additionally, the usage conditions of the multiple links can include the amount of traffic on each link and the air quality of each link.

[0047] At 708, the AP MLD converts the BC frame or MC frame into a unicast frame for the primary link. For example, after the AP MLD 102 obtains the BC frame and MC frame and selects the primary link from among the multiple links, the AP 104-N in the AP MLD corresponding to the primary link is used to convert the BC frame or MC frame 106 into a unicast frame 108.

[0048] At 710, the AP MLD sends the unicast frame to the station MLDs in the station set by using the primary link. For example, after the AP 104-N in the AP MLD 102 generates the unicast frame, the AP MLD 104 sends the unicast frame to the station set 112. The station MLDs or non-MLD stations connected to the primary link will receive the unicast frame via the primary link. The AP MLD will discard the BC frames or MC frames on the other links. Thus, the station MLDs will receive the BC frames or MC frames only on the primary link.

[0049] In this way, the AP MLD can use the selected primary link to send the BC frames or MC frames without using the other links to send the BC frames or MC frames. Thus, the station MLDs will not receive multiple identical BC frames or MC frames. Thereby, when there are many more MLD STAs than non-MLD stations, it avoids wasting time of the STA MLDs as well as wasting channel resources. Additionally, in this way, DMO is applicable to Wi-Fi 7 MLD, and DMO can be used by the AP MLD without causing serious problems on the station side.

[0050] In addition, the AP MLD may send BC frames or MC frames via each of multiple links. The station MLDs in the station set may be of the multi-link single-radio (MLSR) type. This indicates that the station MLD can switch between multiple links. In this case, the station MLD may lose BC frames or MC frames. To avoid this, the AP MLD may determine the least common multiple of the multiple delivery traffic indication message (DTIM) periods of the multiple links as the aligned DTIM period; and send BC frames or MC frames at the aligned DTIM time.

[0051] In addition, transmitting BC frames or MC frames needs to meet some latency drawbacks and security issues because the GTKs between MLD links are different, and the key encryption type needs to be compatible with the lowest-level stations connected to the same BSS. Therefore, the security compatibility issue will affect the reliability of BC / MC. To ensure the security of BC frames or MC frames, the AP MLD 102 may use different group keys to send BC frames or MC frames for station MLDs and non-MLD stations. For example, if a station in the station set lacks ETH capability, the traditional group key is assigned to that station. If a station in the station set has ETH capability, the MLD group key is assigned to the second station.

[0052] In some implementations, to ensure the reliability of BC frames or MC frames, the AP MLD and the station MLD use on-channel tunneling (OCT) operations. In this case, multiple BC frames or MC frames of multiple links are encrypted using their respective group keys and sent to the station MLD via one of the multiple links. For different links in the station MLD, multiple BC frames or MC frames are decrypted with different keys.

[0053] Figure 8 An example AP MLD 800 according to an implementation of the present disclosure is shown. As Figure 8 shown, the AP MLD 800 includes at least one processor 810 and a memory 820 coupled to the processor 810. The memory 820 stores instructions 822, 824, 826, 828, and 830 to cause the processor 810 to perform actions according to the reference implementation of the present disclosure.

[0054] As Figure 8As shown, the memory 820 stores instructions 822 for obtaining a broadcast (BC) frame or a multicast (MC) frame. The memory 820 also stores instructions 824 for determining a plurality of links used by the AP MLD, where the plurality of links are linked between the AP MLD and a set of stations including the station MLD. In addition, the memory 820 further stores instructions 826 for determining a primary link from the plurality of links based on usage conditions of the plurality of links. For example, the primary link can be selected based on one of processing power, health status, traffic volume, or air quality. The memory 820 also stores instructions 828 for converting the BC frame or the MC frame into a unicast frame for the primary link. As Figure 8 shown, the memory 820 also stores instructions 830 for sending the unicast frame to the station MLD in the set of stations by using the primary link.

[0055] The program code or instructions for performing the methods of the present disclosure can be written in any combination of one or more programming languages. These program code or instructions can be provided to a processor or a controller of a general-purpose computer, a special-purpose computer, or other programmable data processing device, such that when the program code is executed by the processor or the controller, the functions / operations specified in the flowchart and / or block diagram are implemented. The program code or instructions can be executed entirely on the machine, partially on the machine as a stand-alone software package, partially on the machine and partially on a remote machine, or entirely on a remote computer or server.

[0056] The program code or instructions for performing the methods of the present disclosure can be written in any combination of one or more programming languages. These program code or instructions can be provided to a processor or a controller of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus, such that when the program code is executed by the processor or the controller, the functions / operations specified in the flowchart and / or block diagram are implemented. The program code or instructions can be executed entirely on the machine, partially on the machine as a stand-alone software package, partially on the machine and partially on a remote machine, or entirely on a remote computer or server.

[0057] In the context of the present disclosure, a machine-readable medium can be any tangible medium that can contain or store a program for use by or in connection with an instruction execution system, apparatus, or device. A machine-readable medium can be a machine-readable signal medium or a machine-readable storage medium. A machine-readable medium can include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, devices, or any suitable combination of the foregoing. More specific examples of a machine-readable storage medium would include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any appropriate combination of the foregoing.

[0058] Moreover, although operations are described in a particular order, this should not be construed as requiring that such operations be performed in the particular order shown or in sequential order, or that all of the illustrated operations be performed to obtain the desired result. In some cases, multitasking and parallel processing may be advantageous. Certain features that are described in separate implementations can also be implemented in combination in a single implementation. Conversely, various features that are described in a single implementation can also be implemented separately or in any suitable sub-combination in multiple implementations.

[0059] In the foregoing detailed description of the present disclosure, reference has been made to the accompanying drawings, which illustrate by way of illustration how examples of the present disclosure may be practiced. These examples have been described in sufficient detail to enable those of ordinary skill in the art to practice the examples of the present disclosure, and it should be understood that other examples may be utilized and that process, electrical, and / or structural changes may be made without departing from the scope of the present disclosure.

Claims

1. A method, comprising: obtaining, by an access point (AP) multi-link device (MLD), a broadcast (BC) frame or a multicast (MC) frame; determining, by the AP MLD, a plurality of links used by the AP MLD, the plurality of links being linked between the AP MLD and a set of stations including a station MLD; determining, by the AP MLD, a primary link from the plurality of links based on usage conditions of the plurality of links; converting, by the AP MLD, the BC frame or the MC frame into a unicast frame for the primary link; and transmitting, by the AP MLD, the unicast frame to the station MLD in the set of stations by using the primary link.

2. The method according to claim 1, wherein determining the primary link from the plurality of links comprises: selecting the primary link from the plurality of links based on at least one of: processing capabilities of a plurality of APs in the AP MLD corresponding to the plurality of links or health states of the plurality of links.

3. The method according to claim 1, wherein determining the primary link from the plurality of links comprises: determining the number of station MLDs in the set of stations connected to each of the plurality of links; and determining the primary link based on the number of the station MLDs.

4. The method according to claim 1, wherein the BC frame or the MC frame is a first BC frame or a first MC frame, and the method further comprises: determining that a second BC frame or a second MC frame is to be transmitted on the plurality of links; determining an aligned delivery traffic indication message (DTIM) period based on a plurality of DTIM periods for the plurality of links; and transmitting the second BC frame or the second MC frame by using the aligned DTIM period.

5. The method according to claim 4, further comprising: generating a first encrypted BC frame or a first encrypted MC frame by encrypting a third BC frame or a third MC frame by using a first set of keys, the first set of keys being related to stations without extremely high throughput (EHT) capabilities; generating a second encrypted BC frame or a second encrypted MC frame by encrypting the third BC frame or the third MC frame by using a second set of keys, the second set of keys being different from the first set of keys and being related to stations with EHT capabilities; and transmitting the first encrypted BC frame or the first encrypted MC frame and the second encrypted BC frame or the second encrypted MC frame on the primary link.

6. The method according to claim 5, wherein the second set of keys is used across the plurality of links.

7. The method according to claim 5, further comprising: determining that a first station in the set of stations lacks EHT capabilities; assigning the first set of keys to the first station; determining that a second station in the set of stations has EHT capabilities; and assigning the second set of keys to the second station.

8. The method according to claim 5, further comprising: broadcasting an on-channel tunneling (OCT) capability in beacon frames on the plurality of links; Encrypt the fourth BC frame or the fourth MC frame by using a third set of keys corresponding to the first link among the multiple links; And Forward the encrypted fourth BC frame or the encrypted fourth MC frame via the second link among the multiple links.

9. The method according to claim 8, further comprising: Encrypt the fifth BC frame or the fifth MC frame by using a second set of keys corresponding to the second link; And Transmit the encrypted fifth BC frame or the encrypted fifth MC frame via the second link.

10. An access point AP multi-link device MLD, comprising: At least one processor; A memory coupled to the at least one processor, the memory storing instructions that cause the at least one processor to: Obtain a broadcast BC frame or a multicast MC frame; Determine a plurality of links used by the AP MLD, the plurality of links being linked between the AP MLD and a set of stations including station MLDs; Determine a primary link from the plurality of links based on usage conditions of the plurality of links; Convert the BC frame or the MC frame into a unicast frame for the primary link; And Send the unicast frame to the station MLDs in the set of stations by using the primary link.

11. The AP MLD according to claim 10, wherein the instructions for determining the primary link from the plurality of links include instructions for causing the at least one processor to: Select the primary link from the plurality of links based on at least one of: the processing capabilities of a plurality of APs in the AP MLD corresponding to the plurality of links or the health status of the plurality of links.

12. The AP MLD according to claim 10, wherein the instructions for determining the primary link from the plurality of links include instructions for causing the at least one processor to: Determine the number of station MLDs in the set of stations connected to each of the plurality of links; and Determine the primary link based on the number of the station MLDs.

13. The AP MLD according to claim 10, wherein the BC frame or the MC frame is a first BC frame or a first MC frame, and the instructions further include instructions for causing the at least one processor to: Determine that a second BC frame or a second MC frame is to be sent on the plurality of links; Determine an aligned DTIM period based on a plurality of delivery traffic indication message DTIM periods for the plurality of links; and Send the second BC frame or the second MC frame by using the aligned DTIM period.

14. The AP MLD according to claim 13, further comprising instructions for causing the at least one processor to: Generate a first encrypted BC frame or a first encrypted MC frame by encrypting a third BC frame or a third MC frame by using a first set of keys related to stations without extremely high throughput EHT capabilities; Generating a second encrypted BC frame or a second encrypted MC frame by encrypting the third BC frame or the third MC frame using a second set of keys, the second set of keys being different from the first set of keys and being related to a station having ETH capabilities; And Transmitting the first encrypted BC frame or the first encrypted MC frame and the second encrypted BC frame or the second encrypted MC frame on the main link.

15. The AP MLD according to claim 14, wherein the second set of keys is used across the plurality of links.

16. The AP MLD according to claim 14, further comprising instructions for causing the at least one processor to: Determine that a first station in the set of stations lacks ETH capabilities; Assign the first set of keys to the first station; Determine that a second station in the set of stations has ETH capabilities; and Assign the second set of keys to the second station.

17. The AP MLD according to claim 14, further comprising instructions for causing the at least one processor to: Broadcast the tunnel OCT capabilities on the beacon frames on the plurality of links on the channel; Encrypt a fourth BC frame or a fourth MC frame using a third set of keys corresponding to a first link among the plurality of links; and Forward the encrypted fourth BC frame or the encrypted fourth MC frame via a second link among the plurality of links.

18. The AP MLD according to claim 17, further comprising instructions for causing the at least one processor to: Encrypt a fifth BC frame or a fifth MC frame using a pair corresponding to the second set of keys of the second link; and Transmit the encrypted fifth BC frame or the encrypted fifth MC frame via the second link.

19. A non-transitory computer-readable medium, comprising instructions stored thereon, the instructions, when executed by an access point AP multi-link device MLD, cause the AP MLD to: Obtain a broadcast BC frame or a multicast MC frame; Determine a plurality of links used by the AP MLD, the plurality of links being linked between the AP MLD and a set of stations including station MLDs; Determine a main link from the plurality of links based on usage conditions of the plurality of links; Convert the BC frame or the MC frame into a unicast frame for the main link; And Transmit the unicast frame to the station MLDs in the set of stations by using the main link.

20. The non-transitory computer-readable medium according to claim 19, wherein the instructions for determining the main link from the plurality of links include instructions for causing the AP MLD to: Select the main link from the plurality of links based on at least one of: the processing capabilities of a plurality of APs in the AP MLD corresponding to the plurality of links or the health status of the plurality of links.

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