CN116634607A - Multilink device and communication method - Google Patents

Abstract

Handover operations are described that provide greater reliability for multi-link operation between access point multi-link devices (AP MLDs) and non-AP MLDs in a wireless communication network. The AP MLD announces one of a plurality of links necessary for the AP MLD to switch the multi-link operation. The non-AP MLD determines whether an AP operating on the handover link has resumed Basic Service Set (BSS) operation on the target channel.

Description

Multilink device and communication method

Technical Field

The present invention relates to the field of communications technologies, and in particular, to a multilink device.

Background

In recent years, the demand for high-speed and reliable wireless communication technology has been increasing. For example, in wireless technologies such as wireless local area networks, there is an increasing or decreasing (unabated) demand for ever-increasing data speeds and reliability.

To support these needs, wireless local area networks contemplate the use of multiple links between an access point and a client device. For example, the access point and the client device use two or more radios to maintain corresponding links between each other. These multiple links may be in different channels or different frequency bands. Given the close physical proximity of multiple radios, challenges exist in ensuring increased data throughput and reliability are achieved. These multiple links typically use the IEEE 802.11 standard, which recently has considered challenges and opportunities for multiple links.

Disclosure of Invention

An aspect of the present invention provides a non-Access Point (AP) multi-link device (MLD) configured to transmit data to or receive data from an AP MLD over a plurality of links, the plurality of links including at least a first link and a second link, the non-AP MLD comprising: a processing circuit; a transceiver coupled to the processing circuit; and a memory coupled to the processing circuit, the memory storing instructions that when executed by the processing circuit perform a plurality of operations including: detecting an indication that a handover link is to be handed over by the AP MLD to a target channel, wherein the handover link is one of the plurality of links; and determining whether an AP affiliated with the AP MLD and operating on the handover link has resumed Basic Service Set (BSS) operation on the target channel.

Another aspect of the invention provides an Access Point (AP) multi-link device (MLD) configured to transmit data to or receive data from a non-AP MLD over a plurality of links, the plurality of links including at least a first link and a second link, the AP MLD comprising: a processing circuit; a transceiver coupled to the processing circuit; and a memory coupled to the processing circuit, the memory storing instructions that, when executed by the processing circuit, perform a plurality of operations including: determining to switch the second link to a target channel, and after determining to switch the second link to the target channel, sending an announcement on the first link instructing the AP MLD to switch the second link to the target channel.

Yet another aspect of the present invention provides a method of transmitting or receiving data over a plurality of links, including at least a first link and a second link, performed by a non-Access Point (AP) multi-link device (MLD) and an AP MLD, the method comprising: the AP MLD sending an announcement to the non-AP MLD, the announcement indicating that a handover link is to be handed over to a target channel, the handover link being one of a plurality of links; and the non-AP MLD determining whether an AP affiliated with the AP MLD and operating on the handover link resumes BSS operation on the target channel.

Wherein the AP MLD transmits a maximum channel switch time element corresponding to the second link to the non-AP MLD in at least one of a beacon frame and a probe response frame on the first link until an AP operating on the second link resumes BSS operation on the target channel; and after the AP operating on the second link resumes BSS operation on the target channel, the AP MLD stops transmitting a maximum channel switch time element.

Wherein after the non-AP MLD detects that an AP belonging to the same AP MLD and operating on a link other than the handover link stops transmitting a maximum channel handover time element corresponding to the AP operating on the handover link, it is determined that the AP operating on the handover link has resumed BSS operation on the target channel.

Yet another aspect of the present invention provides a communication method performed on a non Access Point (AP) multi-link device (MLD) side, the non AP MLD for transmitting data to or receiving data from an AP MLD on a plurality of links including at least a first link and a second link, the method comprising: detecting an indication that a handover link is to be handed over by the AP MLD to a target channel, wherein the handover link is one of the plurality of links; and determining whether an AP affiliated with the AP MLD and operating on the handover link has resumed Basic Service Set (BSS) operation on the target channel. Wherein the communication method performed at a non-Access Point (AP) multi-link device (MLD) side is performed by a processor.

Yet another aspect of the present invention provides a communication method performed at an Access Point (AP) multi-link device (MLD) side for transmitting data to or receiving data from a non-AP MLD over a plurality of links including at least a first link and a second link, the AP MLD comprising: determining to switch the second link to a target channel, and after determining to switch the second link to the target channel, sending an announcement on the first link instructing the AP MLD to switch the second link to the target channel. Wherein the communication method performed at an Access Point (AP) multi-link device (MLD) side is performed by a processor.

Drawings

The present invention is described with reference to the accompanying drawings. In the drawings, like reference numbers indicate identical or functionally similar elements. Furthermore, the leftmost digit(s) of a reference number identifies the figure in which the reference number first appears.

In the drawings:

fig. 1 illustrates an overview of a wireless communication system using multiple links in accordance with some embodiments of the invention.

Fig. 2 illustrates a block diagram of a wireless communication system in accordance with some embodiments of the invention.

Fig. 3 illustrates a block diagram of a non-access point (non-AP) multilink device (MLD) according to some embodiments of the present invention.

Fig. 4 illustrates a block diagram of an Access Point (AP) MLD according to some embodiments of the invention.

Fig. 5 shows a flowchart of the operation of the non-AP MLD according to an embodiment of the present invention.

Fig. 6 shows a flowchart of the operation of the non-AP MLD according to an embodiment of the present invention.

Fig. 7 shows a flowchart of the operation of the AP MLD according to an embodiment of the present invention.

Fig. 8 shows a flowchart of the operation of the non-AP MLD according to an embodiment of the present invention.

FIG. 9 is an example processor system for implementing some aspects or portions.

The present invention will now be described with reference to the accompanying drawings.

Detailed Description

The following description provides many different embodiments, or examples, for implementing different features of the provided subject matter. Specific examples of components and arrangements are described below to simplify the present disclosure. Of course, these are merely examples and are not limiting. For example, forming a first feature over a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed between the first and second features, such that the first and second features may not be in direct contact. Further, the present invention may repeat reference numerals and/or letters in the various examples. Such repetition does not itself dictate a relationship between the various embodiments and/or configurations discussed.

As described above, the wireless local area network (wireless local area network) contemplates the use of multiple links between the access point and the client device to provide increased data throughput and reliability. The IEEE 802.11 standard, which provides a specification governing the operation and performance of wireless local area networks, has begun to consider the use of multiple links. Such multiple links typically use different channels and/or different frequency bands. However, the physical proximity between the multiple radios needs to be considered to ensure that any interference between the multiple radios is properly addressed.

Fig. 1 illustrates an exemplary multi-link operation in a wireless communication network in which multiple access points and multiple non-access points operate together. In multi-link operation, multiple links are formed between a device 110 (e.g., a client device) having multiple non-access points 112, 114 and a device 120 having multiple access points 122, 124. Devices 110, 120 may communicate using multiple links 130,140 to enable fast and/or reliable communication. The devices 110, 120 are referred to as multi-link devices (MLDs).

1. Overview of multilink operation

The present invention is applicable to apparatus, systems, and methods for performing multi-link operations. Hereinafter, fig. 2 is used to illustrate an example of the multilink operation.

Fig. 2 illustrates a block diagram of a wireless communication system in accordance with some embodiments of the invention.

System 200 is a system for multi-link operation. The system 200 includes a non-access point multi-link device (non-AP MLD) 210, an access point multi-link device (AP MLD) 220, a primary link (primary link) 230 and a non-primary link (non-primary link) 240 formed wirelessly between the non-AP MLD 210 and the AP MLD 220.

The non-AP MLD 210 has a first Station (STA) 212 and a second STA 214. Each STA has the necessary components for communicating with an Access Point (AP), such as an antenna, a Radio Frequency (RF) transceiver module, and a baseband processor. Details of the non-AP MLD will be explained below with reference to fig. 3.

Fig. 3 illustrates a block diagram of a non-AP MLD according to some embodiments of the invention. In addition to the first STA 212 and the second STA 214, the non-AP MLD 210 has a processor 300, a memory 302, and a detector (Sensor) 304. The processor 300 controls the components constituting the non-AP MLD 210. The memory 302 temporarily or permanently stores information necessary for the operation of the non-AP MLD 210. The detector 304 detects the signal strength to monitor the quality of wireless communications performed by the non-AP MLD 210. The non-AP MLD 210 may also have a third STA 306, components omitted in fig. 2 for simplicity. In various embodiments of the invention, an MLD may have two or more STAs or APs.

Returning to fig. 2, the AP MLD 220 has a first Access Point (AP) 222 and a second AP 224. Each AP has the necessary components for communicating with the STA, such as an antenna, an RF transceiver module, and a baseband processor. Details of the non-AP MLD will be explained below with reference to fig. 4. In the present invention, each link may include an antenna and an RF transceiver module of the non-AP MLD 210 and the AP MLD 220.

Fig. 4 illustrates a block diagram of an AP MLD according to some embodiments of the present invention. The description of each component of the AP-MLD 220 is substantially similar to the description of the corresponding components in the non-AP MLD 210 described in fig. 3, and thus the description of these components is omitted.

Returning to fig. 2, the primary link 230 is a wireless link formed between the first STA 212 and the first AP 222. The non-primary link 240 is a wireless link formed between the second STA 214 and the second AP 224. Each link uses its assigned channel operating class (operating class) and the channel corresponding to the channel number or the channel corresponding to the assigned channel number as its communication channel, where the operating class indicates information of the channel set, indicates the starting frequency at which the channel set is located, the channel spacing, and the channel number of each channel in the set, e.g., operating class 1, which contains four channel numbers 36,40,44,48, the link can use the channel corresponding to the channel number (e.g., 36). In the present invention, the plurality of links established between the non-AP MLD 210 and the AP MLD 220 for the multilink operation may be referred to as multilink. In the present invention, the main link 230 may also be referred to as a first link, the non-main link 240 as a second link, and the additional links described below as a third link.

As shown in fig. 2, the communication operation using the multilink is called a multilink operation. The multilink operation may include two modes of operation.

The simultaneous transmit and receive mode of operation (transmit and receive operation, STR) is one mode of operation. In STR mode, multiple links operate independently. Thus, each link can simultaneously transmit and receive data.

The non-STR (NSTR) mode is another mode of operation. In the NSTR mode, the multiple links do not operate independently of each other. For example, if data cannot be successfully transmitted and received, operation in STR mode cannot be guaranteed. In this case, the STR mode is not possible, and the NSTR mode becomes necessary.

One principle of selecting which of these modes to use is potentially or actually existing in-device coexistence (in-device coexistence, IDC) interference. For example, when multiple links of a multi-link operation are close to each other, IDC interference exists for the MLD device. An MLD operating on multiple links and having IDC interference may not support STR operation modes. Therefore, in this case, the NSTR operation mode is preferable.

As will be appreciated by those of ordinary skill in the art, it is desirable to use the STR mode of operation whenever possible because the simultaneous use of links maximizes data throughput. However, the disturbances may prevent the use of STR modes of operation.

When the MLD operates using the NSTR mode, the non-AP MLD and the AP MLD can avoid IDC interference by performing contention-based channel access on respective links and simultaneously starting transmission using the following constraints, as described below.

An example of the non-AP MLD 210 transmitting data to the AP MLD 220 in the NSTR mode is shown in fig. 1. In NSTR mode, at least one link is designated as a primary link and the other links are defined as non-primary links. As already explained, in the example of fig. 2, one link is the primary link 230 and the other link is the non-primary link 240. To transfer data from the non-AP MLD 210 to the AP MLD 220, the first STA 212 and the second STA 214 should initiate PPDUs (PLCP Protocol Data Unit, PLCP protocol data units) transmissions of the primary link (or first link) 230 and the non-primary link (second link) 240, where PLCP is a physical layer convergence protocol (Physical Layer Convergence Protocol). However, in the NSTR mode, only the first STA 212 (operating in the primary link and affiliated with the same MLD as the second STA) that is the holder of the transmission opportunity (transmit opportunity, TXOP) for the same start time initiates PPDU transmission, the second STA may initiate PPDU transmission for the second link 240. This is because there is a risk of IDC if one STA transmits a signal while another STA belonging to the same MLD receives a signal independently at the same time. Accordingly, in the NSTR mode, one STA among the plurality of STAs becomes a reference, and the reference STA transmits a signal while the other STAs transmit signals.

As shown in fig. 2, the first STA 230 and the second STA 240 initiate enhanced distributed channel access (enhanced distributed channel access, EDCA) backoff 232 and 242 on each link as TXOP initiators. In the example shown in fig. 2, the first link 230 is allocated a Random Backoff (RBO) count of four slots and the second link 240 is allocated a RBO count of six slots. When the RBO count of the first link 230 decreases to zero, the first STA 212 becomes idle waiting for the RBO count of the second link 240 to decrease, with a waiting period 234 as shown in fig. 2. Thereafter, when the RBO count of the second link 240 is decremented to zero, and if the first STA 212 is still idle, the first STA 212 and the second STA may transmit messages 236 and 244 with the first AP and the second AP. The second STA 214 may use its detector to detect whether the first STA 212 is still idle. Messages 236 and 244 may contain an uplink data PPDU and a Block Ack (BA). The start of the PPDU on the waiting link (primary link 230 in the example of fig. 2) should be aligned with the start of the PPDU on the other link (secondary link 240 in the example of fig. 2). The end of PPDUs on the first link 230 and the second link 240 also need to be aligned.

However, if a link needs to switch its channel operation class/channel number, due to interference, regulatory requirements, or other reasons, the non-AP MLD 210 affiliated with the AP MLD 220 may not be able to switch to the new channel indicated by the AP MLD 220, or the non-AP MLD 210 may not know when the AP MLD 220 resumes basic service set (basic service set, BSS) operation on the new channel, so transmissions on the new channel initiated by the non-AP MLD 210 or the AP MLD 220 may fail and spectrum (spectral) efficiency may be reduced. To solve this problem, an exemplary channel switching scheme is proposed in the present invention. According to one example of the present invention, the non-AP MLD 210 may inform whether or not it is possible to switch and request to continue communication according to its own situation. According to one example of the invention, the AP MLD 220 may announce a handoff of the non-primary link 240 through the primary link 230 even though they are operating in the NSTR mode. In accordance with one example of the present invention, after the channel switching of the non-primary link 240 has been completed, the AP MLD 220 may indicate in the beacon frame and probe response frame on the primary link 230 that BSS operation has resumed on the new channel of the non-primary link 240 by stopping transmitting the maximum channel switching time (Max Channel Switch Time) element in the STA profile sub-element. According to one example of the present invention, the non-AP MLD 210 and the AP MLD 220 may remain in communication even if the AP MLD 220 decides not to switch the non-main link 240 to a new channel. It is emphasized here again that the present invention is not only applicable to systems operating in the NSTR mode. In a system operating in non-NSTR mode, if the AP MLD schedules a channel switch of the link to a new channel operation class/channel number, then the behavior of the associated non-AP MLD is preferably defined.

2. Channel switching scheme for non-AP MLD

2.1 switching non-Main links

This section shows the operation of the non-AP MLD 210 when the AP MLD 220 switches the non-main link 240.

Fig. 5 shows a flowchart of the operation of the non-AP MLD according to an embodiment of the present invention. The processing of each operation is performed by the processor 300 of the non-AP MLD 210 in cooperation with other components thereof, unless otherwise specified.

In operation 500, the non-AP MLD 210 transmits/receives data to/from the AP MLD 220.

In operation 502, the non-AP MLD 210 determines whether the non-AP MLD 210 detects a handover of the non-main link 240. The non-AP MLD 210 may detect the handoff of the non-main link 240 in a variety of ways. One example of detecting a handover of the non-primary link 240 is the method of the present invention described later. The switching method of the non-main link 240 is not limited to the method described in the present invention; for example, the AP MLD may directly or indirectly notify the non-AP MLD that a handoff has occurred, or may be notified by a system administrator automatically or manually.

If the non-AP MLD 210 does not detect a handoff of the non-primary link 340, the process returns to operation 500.

When the non-AP MLD 210 detects a handoff, the process moves to operation 504. The non-AP MLD 210 may also detect the target channel simultaneously. The target channel is the channel to which the operating channel of the non-primary link 240 is to be switched. The target channel is identified by information indicating, for example, a channel operation class/channel number. The non-AP MLD 210 may also detect the target handoff time simultaneously. The target handoff time is information that provides the time when the AP MLD 220 will begin handoff of the non-primary link 240 to the target channel.

In operation 504, the non-AP MLD 210 determines whether the non-AP MLD 210 switches to the target channel. There are a number of reasons for not switching to the target channel. For example, one reason for not switching to the target channel includes interference, regulatory requirements, or other similar reasons.

If the non-AP MLD 210 determines to switch to the target channel, the process moves to operation 506. In operation 506, the non-AP MLD 210 determines whether the target handover time is reached, and if the target handover time is not reached, continues to wait for the target handover time to reach.

In operation 508 (non-AP MLD 210 determines "no" in operation 504), the non-AP MLD 210 determines whether the target handoff time is reached.

If the non-AP MLD 210 determines in operation 508 that the target handoff time has not elapsed, the process moves to operation 510. In operation 510, the non-AP MLD 210 transmits a request to the AP MLD 220.

The request is a message indicating that the non-AP MLD 210 removes the handover link from the plurality of links already established between the AP MLD 220 and the non-AP MLD 210. Here, the handover link refers to a link to be handed over (referred to as a non-main link 240 in this section). The request may take various forms. Some examples of which are described below.

One example of a request is a request for a mapping of a traffic identifier (Traffic Identifier, TID) to a link. TID is an identifier that identifies the data frame to be transmitted over the link. The TID-to-link mapping request indicates a mapping between the TID and a link transmitting a data frame having the TID. At operation 510, the non-AP MLD 210 may send a TID-to-link mapping request that maps TID to a link of the non-handover link to avoid communication over the handover link, wherein the non-AP MLD 210 has decided not to handover to the target channel of the handover link. The TID-to-link mapping request may preferably include a target timer indicating a point in time at which the non-AP MLD 210 will begin the requested mapping, e.g., a point in time at which to convert from an existing mapping manner to the requested mapping manner. It may be better to use TID-to-link mapping requests as an example of a request for the following reasons. The handoff can be accomplished quickly and easily since it is not necessary to re-associate the connection between the non-AP MLD 210 and the AP MLD 220.

Another example of a request is a reassociation request. The reassociation request is a request to establish a new link or a new multilink. During the re-association performed, the AP MLD 220 or the non-AP MLD 210 may avoid including the handover link operating on the target channel in the new link or the new multilink.

Another example of a request is a link reconfiguration request or a remove request. The link reconfiguration request or the removal request is a request to delete the handover link from the multi-link configuration. The request may include a delete timer (delete timer) to indicate the time to delete the link. Using a link reconfiguration request or a removal request as an example of a request has advantages. The handoff can be accomplished quickly and easily since it is not necessary to re-associate the connection between the non-AP MLD 210 and the AP MLD 220.

The link that sends the request may be a primary link or a non-primary link. However, in some cases, the AP MLD 220 forces the non-AP MLD 210 to stop transmitting until a channel switch occurs by setting a channel switch mode in a channel switch announcement (Channel Switch Announcement) element or an extended channel switch announcement (Extended Channel Switch Announcement) element. In this case, the request can only be sent on other links that are in use by the non-AP MLD 210.

If the target handoff time has elapsed, the non-AP MLD 210 sends a request using the link of the non-handoff link at operation 512 because the handoff link is not available at this time.

If the non-AP MLD 210 determines that the target switching time arrives in operation 506, the non-AP MLD 210 switches the non-main link 240 to the target channel in operation 513. After the target handoff time arrives, the non-AP MLD 210 receives a maximum channel handoff time element corresponding to the AP 224 of the AP MLD220 (the AP operating on the handoff link) at operation 514. The maximum channel switch time element indicates an estimated time between the time the maximum channel switch time element is transmitted and the time the second AP 224 of the AP MLD220 resumes BSS operation on the new channel of the non-primary link 240. The beacon frames and probe response frames sent by the AP MLD220 include multiple link elements. The multi-link element includes a STA profile (Per STA profile) sub-element corresponding to a non-primary link. Since the first AP 222 of the AP MLD220 (the AP operating on the non-switching link) still transmits the beacon frame or the probe response frame, the AP MLD220 may inform the non-AP MLD 210 of the estimated time for the BSS operation to resume on the target channel of the switching link.

In operation 516, the non-AP MLD 210 determines whether the AP 222 of the AP MLD220 stops transmitting the maximum channel switching time element.

If the non-AP MLD 210 determines that the AP 222 stops transmitting the maximum channel switch time element, the non-AP MLD 210 determines that the AP 224 of the AP MLD 220 resumes BSS operation at operation 518. This is because the AP MLD 220 may stop transmitting the element after detecting that the AP 224 resumes BSS operation. After determining that the AP 224 of the AP MLD resumes BSS operation, the non-AP MLD 210 may resume multi-link operation.

2.2 Handover Main Link

This section shows the operation of the non-AP MLD 210 when the AP MLD 220 switches the main link 230. In this section, multilink operation is performed by using the NSTR mode non-AP MLD 210 and the AP MLD 220.

Fig. 6 shows a flowchart of the operation of the non-AP MLD according to an embodiment of the present invention. The processing of each operation is performed by the processor 300 of the non-AP MLD 210 in cooperation with other components, unless otherwise specified.

In operation 600, the non-AP MLD 210 transmits data to the AP MLD 220 or the non-AP MLD 210 receives data from the AP MLD 220.

In operation 602, the non-AP MLD 210 determines whether the non-AP MLD 210 detects a handover of the main link 230. The non-AP MLD 210 may detect the handoff of the non-main link 230 in a variety of ways.

If the non-AP MLD 210 does not detect a handoff of the primary link 230, the process returns to operation 600.

When the non-AP MLD 210 detects a handoff, the process moves to operation 604. The non-AP MLD 210 may also detect the target channel simultaneously.

In operation 604, the non-AP MLD 210 determines whether the non-AP MLD 210 is to switch to a target channel.

If the non-AP MLD 210 determines to switch to the target channel, the process moves to operation 606. In operation 606, the non-AP MLD 210 switches the primary link 230 to the target channel.

At operation 608 (non-AP MLD 210 determines "no" at operation 604), non-AP MLD 210 determines whether non-AP MLD 210 and AP MLD 220 have established additional links in addition to primary link 230 and non-primary link 240. For example, the non-AP MLD 210 and the AP MLD 220 may establish a third link between the third STA 306 and the third AP 406.

If the non-AP MLD 210 determines that an additional link exists, the process moves to operation 610. In operation 610, the non-AP MLD 210 sends a request to the AP MLD 220 on an additional link.

The examples of the request are in principle similar to the examples given in section 2.1, but differ from them in several ways as follows.

If the non-AP MLD 210 transmits a TID-to-link mapping request as a request at operation 610, the non-AP MLD 210 may transmit a TID-to-link mapping request that maps TIDs to links (e.g., additional links) that are not primary links and non-primary links. This is because, as already explained, the non-primary link 240 cannot initiate communication without the primary link 230.

If the non-AP MLD 210 sends a re-association request as a request, the AP MLD 220 or the non-AP MLD 210 may attempt not to include the primary link and the non-primary link into a new link or a new multilink during the re-association is performed in operation 610.

If the non-AP MLD 210 transmits a link reconfiguration request or a removal request as a request, a deletion timer (the delete timer) indicates a time when both links are to be deleted in operation 610. If the non-AP MLD 210 determines that there is no additional link, the process moves to operation 612. At operation 612, the non-AP MLD 210 transmits a disassociation (association) frame over the main link 230. After transmitting the disassociation frame, the non-AP MLD 210 initiates a multi-link tear down (teardown) procedure.

Channel switching scheme for ap MLD.

This section illustrates the operation of the AP MLD 220 when the AP MLD 220 determines to switch the non-primary link 240. In this section, the non-AP MLD 210 and the AP MLD 220 perform a multi-link operation by using the NSTR mode.

Fig. 7 shows a flowchart of an AP MLD operation according to an embodiment of the present invention. The processing of each operation is performed by the processor 400 of the AP MLD 220 in cooperation with other components, unless otherwise specified.

In operation 700, the AP MLD 220 transmits data to the non-AP MLD 210 or the AP MLD 220 receives data from the non-AP MLD 210.

In operation 702, the AP MLD 220 determines whether the AP MLD 220 is to switch the non-main link 240 to the target channel. If the AP MLD 220 does not have to switch the non-primary link 240 to the target channel, the process returns to operation 700.

In operation 704, the AP MLD 220 transmits an announcement (advertisement) to the non-AP MLD 210. The announcement instructs the AP MLD 220 to switch the non-primary link to the target channel. The announcement indicates the operation class/channel number of the target channel. The announcement may further indicate a target switch time.

The announcement may take various forms, some examples of which are described below.

One example of an announcement is a channel switch announcement (Channel Switch Announcement) element or an extended channel switch announcement (Extended Channel Switch Announcement) element sent over the main link 230. The AP MLD 220 periodically transmits a beacon frame on the main link 230. The AP MLD 220 also transmits a probe response frame on the main link 230 as a response to the probe request from the non-AP MLD 210. The beacon frame and the probe response frame include multiple link elements. The multilink element includes a STA profile sub-element. The STA profile sub-element corresponding to the non-primary link of the multi-link element carries the profile of the non-primary link 240. In operation 704, the ap MLD 220 may indicate the handover of the non-primary link 240 by including a channel handover announcement element or an extended channel handover announcement element in a STA profile sub-element corresponding to the non-primary link. In this way, the announcement may be sent in a beacon frame or a probe response frame.

The channel switch announcement element or the extended channel switch announcement element may be carried in a channel switch announcement frame or an extended channel switch announcement frame transmitted over the main link 230. These frames are not transmitted in beacon frames or probe response frames.

A channel switch announcement element, an extended channel switch announcement element, a channel switch announcement frame, and an extended channel switch announcement frame may be sent on a link to indicate a channel switch for the link. However, in the present invention, this scheme uses elements/frames to indicate channel switching of other links.

The frame carrying the channel switch announcement element or the extended channel switch announcement element may indicate link ID information of the non-main link 240 to indicate which link to switch. The AP MLD 220 may indicate the link ID in various ways.

The link ID information may be the MAC address of the second AP 224, which is described as an A3 address in the MAC header of the corresponding frame. The AP MLD 220 may indicate the link ID information by indicating the MAC address of the AP operating on the non-primary link 240 that is affiliated with the AP MLD 220. Thus, the AP MLD 220 may indicate the MAC address of the second AP 224 as the A3 address.

The AP MLD 220 may also indicate link ID information by using a link ID subfield of the corresponding frame. The link ID information corresponds to the link ID of the non-main link 240.

Another example of an announcement is that the content of the announcement is described in a neighbor AP information field in a reduced neighbor report (Reduced Neighbor Report, RNR) element in a beacon frame on the main link 230 that corresponds to the non-main link 240. As described above, the AP MLD 220 periodically transmits a beacon frame on the main link 230. The beacon frame includes various elements. The RNR element is one of a plurality of elements and is used to inform the state of neighbor APs. The RNR may include a state of the second AP 224 corresponding to the non-primary link 240. The neighbor AP information field of the RNR has an operation Class (Operating Class) field and a Channel Number (Channel Number) field. In operation 704, the AP MLD 220 includes an operation class/channel number of the target channel at the target handover time in an operation class field or a channel number field of a neighbor AP information field corresponding to the non-primary link 240 in the RNR element.

In operation 706, the AP MLD 220 determines whether the AP MLD 220 failed to switch (fail) or decides not to switch to the target channel. If the AP MLD 220 has not failed the handoff or has not decided not to handoff to the target channel, the process moves to operation 708. In operation 708, the ap MLD 220 determines whether the target handoff time is reached, and if the target handoff time is not reached, continues to wait for the target handoff time to reach.

In operation 711, after reaching the target switching time, the AP 222 of the AP MLD 220 switches to the target channel. After reaching the target handoff time, the AP MLD 220 may transmit a maximum channel switch time element corresponding to the AP 224 by using a beacon frame or a probe response frame, indicating an estimated time between the time the maximum channel switch time element was transmitted and the time the AP 224 resumes BSS operation on a new channel other than the main link 240, at operation 712. As previously described, the beacon frame or probe response frame sent by the AP MLD 220 includes a multilink element. The multilink element includes STA profile sub-elements corresponding to the non-primary link 240. Since the first AP 222 of the AP MLD 220 (the AP operating on the non-switching link) is still able to transmit the beacon frame or the probe response frame, the AP MLD 220 may inform the non-AP MLD 210 of the estimated time to resume BSS operation on the target channel of the switching link.

In operation 714, the AP MLD 220 determines whether the second AP 224 resumes BSS operation on the non-primary link (the link being switched).

After determining that the second AP 224 resumes BSS operation on the non-primary link (the link being switched), the AP MLD 220 stops transmitting the maximum channel switch time element. In this way, the AP MLD 220 may inform the non-AP MLD 210 that the second AP 224 resumes BSS operation on the non-main link (switched link). Corresponding to operations 712 to 716 described above, the non-AP MLD 210 also performs operations 810 to 814 described later.

Note that operations 712 through 716 also apply to multilink operation operating in modes other than the NSTR mode. If the AP MLD 220 switches one of the links, an AP operating on a link other than the switching link of the AP MLD 220 transmits a maximum channel switching time element corresponding to the AP operating on the switching link by using a beacon frame or a probe response frame.

If the AP MLD 220 fails to switch to the target channel or decides not to switch to the target channel and the AP MLD 220 includes the operation class/channel number of the target channel in the operation class field or the channel number field, the process moves to operation 710. In operation 710, the ap MLD 220 transmits a new announcement. The AP MLD 220 may maintain the current operation class/channel number of the non-main link 240 in the operation class field or the channel number field at or after the target handoff time. In other words, the AP MLD 220 sets the operation class and channel number fields in the RNR element corresponding to the non-main link 240 to the original operation class and channel number of the non-main link 240 (second link), which were the operation class and channel number in which the handover link (e.g., the non-main link 240) was operated before the operation to switch to the target channel was to be performed.

When the AP MLD220 performs operation 710, the non-AP MLD 210 may detect that the AP MLD220 has not switched. The operation of the non-AP MLD 210 at this time will be explained with reference to fig. 8.

Fig. 8 shows a flowchart of the operation of the non-AP MLD according to an embodiment of the present invention. The processing of each operation is performed by the processor 300 of the non-AP MLD 210 in cooperation with other components, unless otherwise specified.

In operation 800, the non-AP MLD 210 transmits data to the AP MLD220 or the non-AP MLD 210 receives data from the AP MLD 220.

In operation 802, the non-AP MLD 210 receives the announcement transmitted in operation 704. In this case, the AP MLD220 transmits an announcement by including an operation class/channel number of the target channel at the target handover time into an operation class field or a channel number field of a neighbor AP information field corresponding to the non-primary link 240 in the RNR element in operation 704.

In operation 804, the non-AP MLD 210 determines whether the target handover time is reached. If the target handoff time has not been reached, the process returns to operation 800.

If the target switching time has elapsed, the process moves to operation 806. In operation 806, the non-AP MLD 210 determines whether the latest announcement data shows that the AP MLD220 switches the switching link (non-main link in this embodiment) to the target channel. When the non-AP MLD 210 recognizes that the target operation class/channel number of the non-primary link is presented in the operation class field and the channel number field of the neighbor AP information field corresponding to the non-primary link 240 in the RNR element, the non-AP MLD 210 determines that the latest announcement shows that the AP MLD220 switches the handover link to the target channel.

If the non-AP MLD 210 determines that the latest announcement shows that the AP MLD 220 has not switched the handover link to the target channel, the process returns to operation 800.

If the non-AP MLD 210 determines that the latest announcement shows that the AP MLD 220 switches the handover link to the target channel, the process moves to operations 808 and 810. In operation 808, the non-AP MLD 210 switches the non-main link 240 to the target channel.

Operations 810, 812, and 814 are substantially the same as operations 514 through 518, and thus the description is omitted.

As described in the above section, the reliability of the multi-link operation is improved even if one link needs to switch channel operation class/channel number for any reason. The non-AP MLD 210 may inform whether handover is possible or not and request to continue communication according to its own situation. The AP MLD 220 may announce a handoff of the non-primary link 240 on the primary link 230 even though they are operating in the NSTR mode. The non-AP MLD 210 and the AP MLD 220 may maintain communication even if the AP MLD 220 decides not to switch links.

The various aspects disclosed above may be implemented, for example, using one or more processor systems, such as the processor system 900 shown in fig. 9. Processor system 900 may be any well-known computer capable of performing the functions described herein, such as devices 210 and 220 of fig. 2. The processor system 900 includes one or more processors (also referred to as central processing units or CPUs), such as a processor 904. The processor 904 is connected to a communication infrastructure 906 (e.g., a bus). The processor system 900 also includes a user input/output device 903, such as a monitor, keyboard, pointing device (pointing device), etc., that communicates with the communication infrastructure 906 via the user input/output interface 902. The processor system 900 also includes a main memory or main memory 908, such as random access memory (random access memory, RAM). Main memory 908 may include one or more levels of cache. Main memory 908 has stored therein control logic (e.g., computer software) and/or data.

The processor system 900 may also include one or more secondary storage devices or memory 910. Secondary memory 910 may include, for example, a hard disk drive 912 and/or a removable storage device or drive 914. Removable storage drive 914 may be a floppy disk (floppy disk) drive, a magnetic tape drive, an optical disk drive, an optical storage device, a magnetic tape backup device, and/or any other storage device/drive.

Removable storage drive 914 may interact with a removable storage unit 918. Removable storage unit 918 includes a computer usable or readable storage device having stored thereon computer software (control logic) and/or data. Removable storage unit 918 may be a floppy disk, magnetic tape, optical disk, DVD, optical storage disk, and/or any other computer data storage device. Removable storage drive 914 reads from and/or writes to a removable storage unit 918 in a well known manner.

According to some aspects, secondary memory 910 may include other means, tools, or other methods for allowing computer programs and/or other instructions and/or data to be accessed by processor system 900. Such means, tools, or other methods may include, for example, a removable storage unit 922 and an interface 920. Examples of removable storage unit 922 and interface 920 can include a program cartridge and cartridge interface (e.g., as an interface in a video game device), a removable memory chip (e.g., as an EPROM, or PROM) and associated socket, a memory stick (memory stick) and USB port, a memory card and associated memory card slot, and/or any other removable storage unit and associated interface.

The processor system 900 may also include a communication or network interface 924. Communication interface 924 enables processor system 900 to communicate and interact (individually and collectively referenced by reference numeral 928) with any combination of remote devices, remote networks, remote entities, etc. For example, communication interface 924 may allow processor system 900 to communicate with remote device 928 via communication path 926, which communication path 926 may be wired and/or wireless, and may include any combination of a LAN, WAN, the internet, etc. Control logic and/or data may be transmitted to the processor system 900 and from the processor system 900 via the communication path 926.

The operations of the foregoing aspects may be implemented in a wide variety of configurations and architectures. Thus, some or all of the operations of the foregoing aspects may be performed in hardware, software, or both. In some aspects, a tangible, non-transitory apparatus or article of manufacture comprises a tangible, non-transitory computer-usable or readable medium having control logic (software) stored thereon, also referred to herein as a computer program product or program storage device. This includes, but is not limited to, processor system 900, main memory 908, secondary memory 910, and removable storage units 918 and 922, as well as tangible articles of manufacture embodying any combination of the foregoing. Such control logic, when executed by one or more data processing devices (e.g., processor system 900), causes such data processing devices to operate as described herein.

Based on the teachings contained in the present invention, it will be apparent to those skilled in the relevant art how to make and use aspects of the invention using data processing devices, computer systems, and/or computer architectures other than the components in FIG. 9. In particular, aspects may operate with software, hardware, and/or operating system implementations other than those described herein.

It should be understood that the detailed description section, and not the summary and abstract sections, is intended to be used to interpret the claims. The summary and abstract sections may set forth one or more, but not all exemplary embodiments of the invention, and thus are not intended to limit the invention and the appended claims in any way.

The invention has been described above with the aid of functional building blocks illustrating the implementation of specific functions and relationships thereof. For convenience of description, boundaries of these functional building blocks are arbitrarily defined herein. Alternate boundaries may be defined so long as the specified functions and relationships thereof are appropriately performed.

The foregoing description of the specific embodiments will so fully reveal the general nature of the invention that others can, by applying knowledge within the skill of the art, readily modify and/or adapt for various applications such specific embodiments without undue experimentation, without departing from the generic concept of the present invention. Thus, such modifications and/or variations are intended to be within the meaning and scope of equivalents of the disclosed embodiments in accordance with the teachings and guidance presented herein. It is to be understood that the phraseology or terminology herein is for the purpose of description and not of limitation, such that the terminology or phraseology of the present specification is to be interpreted by the skilled artisan in light of the teachings and guidance.

The breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.

Claims (22)

1. A communication method performed on the non-access point, AP, multi-link device, MLD, side for transmitting data to or receiving data from the AP MLD on a plurality of links, including at least a first link and a second link,

detecting an indication that a handover link is to be handed over by the AP MLD to a target channel, wherein the handover link is one of the plurality of links; and

it is determined whether an AP affiliated with the AP MLD and operating on the handover link has resumed basic service set BSS operation on the target channel.

2. The communication method of claim 1, wherein,

determining whether an AP affiliated with the AP MLD and operating on the handover link has resumed BSS operation on the target channel includes:

after detecting that an AP that is affiliated with the same AP MLD and that is operating on a link that is not a handover link stops transmitting a maximum channel switch time element corresponding to the AP that is operating on the handover link, it is determined that the AP that is operating on the handover link has resumed BSS operation.

3. The communication method of claim 2, wherein the maximum channel switch time element indicates an estimated time between a time when the maximum channel switch time element is transmitted and a time when the AP on the switch link resumes BSS operation on a target channel.

4. The communication method as claimed in claim 1, further comprising:

determining whether the non-AP MLD switches the handover link to the target channel, and

after determining that the non-AP MLD is not switching the switching link to the target channel, a request is sent for instructing the non-AP MLD to remove the switching link from the plurality of links.

5. The communication method as set forth in claim 4, further comprising:

detecting target switching time, wherein the target switching time is the time when the switching link is scheduled to start switching to the target channel;

transmitting a request on at least one of the plurality of links prior to the target handoff time; and/or the number of the groups of groups,

the request is sent on at least one of the plurality of links that is not the handover link after the target handover time.

6. The communication method of claim 4, wherein the request is at least one of:

a mapping request from a service identifier TID to a link;

re-association request;

and a link reconfiguration request for requesting deletion of the handover link from the plurality of links.

7. The communication method of claim 1, wherein,

the non-AP MLD is configured to transmit data to or receive data from the AP MLD, wherein the AP MLD operates in a non-simultaneous transmit and receive operation NSTR mode; the first link is the switching link and the main link; and the second link is a non-primary link.

8. The communication method of claim 4, wherein,

the non-AP MLD is configured to transmit data to or receive data from the AP MLD operating in the NSTR mode;

the first link is the switching link and the main link;

the second link is a non-primary link;

the request is a disassociation frame to initiate a tear down procedure, and

the method also comprises the following steps:

detecting whether the plurality of links includes only a primary link and a non-primary link,

The sending the request includes:

the request is sent upon detecting that the plurality of links includes only the primary link and the non-primary link.

9. The communication method of claim 4, wherein,

the non-AP MLD is configured to transmit data to or receive data from the AP MLD operating in the NSTR mode;

the first link is the switching link and the main link;

the second link is a non-primary link;

the request is at least one of:

TID to link mapping request;

re-association request; and

requesting to delete a link reconfiguration request for said primary link and said non-primary link, and

the method further comprises the steps of:

detecting whether a plurality of links includes additional links in addition to the primary link and the non-primary link,

the sending the request includes:

the request is sent after detecting that the plurality of links includes the additional link, the request requesting that the TID be mapped to the additional link.

10. The communication method of claim 4, wherein,

the non-AP MLD is configured to transmit data to or receive data from the AP MLD operating in the NSTR mode;

The first link is a primary link;

the second link is the switching link and the non-main link; and

the method further comprises the steps of:

detecting target switching time, wherein the target switching time is the time when the switching link is scheduled to start switching to a target channel, and the target channel is indicated by a target channel operation type and a channel number; and

and after the target switching time is reached, after the target channel operation type and the channel number indicated in the simplified neighbor report element corresponding to the non-main link are detected to be the original channel operation type and the channel number of the non-main link, the non-main link is maintained.

11. A communication method for execution on an access point, AP, multi-link device, MLD, side, wherein the AP MLD is configured to transmit data to or receive data from a non-AP MLD on a plurality of links, the plurality of links including at least a first link and a second link, the AP MLD comprising:

determining to switch the second link to a target channel, and

after determining to switch the second link to the target channel, an announcement is sent on the first link instructing the AP MLD to switch the second link to the target channel.

12. The communication method of claim 11, wherein the AP MLD is configured to transmit data to or receive data from a non-AP MLD using an NSTR mode; the first link is a primary link; and the second link is a non-primary link.

13. The communication method of claim 11, wherein transmitting an announcement over the first link comprises: the announcement is sent by including the announcement in at least one of a beacon frame and a probe response frame sent on the first link.

14. The communication method of claim 11, wherein the announcement indicates link ID information of the second link.

15. The communication method of claim 11, wherein,

the announcement indicates at least one of an operation class and a channel number of the target channel; and

the plurality of operations also includes transmitting the announcement by including the announcement in a beacon frame transmitted on the first link.

16. The communication method according to claim 13 or 15, characterized by further comprising: sending an announcement indicating a target switching time to a non-AP MLD, the target switching time being a time when the second link is scheduled to start switching to a target channel;

And after determining that the AP MLD does not switch the second link to the target channel at or after the target switching time, setting a channel operation category and a channel number field in a simple neighbor report element corresponding to the second link as an original channel operation category and a channel number of the second link.

17. The communication method as claimed in claim 11, further comprising: transmitting a maximum channel switch time element corresponding to the second link to the non-AP MLD in at least one of a beacon frame and a probe response frame on the first link until an AP operating on the second link resumes basic service set BSS operation on the target channel; and

and stopping sending the maximum channel switching time element after the AP operating on the second link resumes BSS operation on the target channel.

18. The communication method of claim 17, wherein,

the maximum channel switch time element indicates an estimated time between a time when the maximum channel switch time element is transmitted and a time when the AP on the second link resumes BSS operation on a target channel.

19. A non-access point, AP, multi-link device, MLD, configured to transmit data to, or receive data from, an AP MLD over a plurality of links, the plurality of links including at least a first link and a second link, the non-AP MLD comprising:

a processing circuit;

a transceiver coupled to the processing circuit; and

a memory coupled to the processing circuitry, the memory storing instructions that, when executed by the processing circuitry, perform a plurality of operations including:

detecting an indication that a handover link is to be handed over by the AP MLD to a target channel, wherein the handover link is one of the plurality of links; and

it is determined whether an AP affiliated with the AP MLD and operating on the handover link has resumed basic service set BSS operation on the target channel.

20. The non-AP MLD of claim 19, wherein,

after detecting that an AP that is affiliated with the same AP MLD and that is operating on a link that is not a handover link stops transmitting a maximum channel switch time element corresponding to the AP that is operating on the handover link, it is determined that the AP that is operating on the handover link has resumed BSS operation.

21. An access point, AP, multi-link device, MLD, configured to transmit data to or receive data from a non-AP, MLD, over a plurality of links, the plurality of links comprising at least a first link and a second link, the AP MLD comprising:

a processing circuit;

a transceiver coupled to the processing circuit; and

a memory coupled to the processing circuitry, the memory storing instructions that, when executed by the processing circuitry, perform a plurality of operations including:

determining to switch the second link to a target channel, and

after determining to switch the second link to the target channel, an announcement is sent on the first link instructing the AP MLD to switch the second link to the target channel.

22. The AP MLD of claim 21, wherein,

the plurality of operations further includes:

transmitting a maximum channel switch time element corresponding to the second link to the non-AP MLD in at least one of a beacon frame and a probe response frame on the first link until an AP operating on the second link resumes basic service set BSS operation on the target channel; and

And stopping sending the maximum channel switching time element after the AP operating on the second link resumes BSS operation on the target channel.