Beacon frame transmission method in EMLSR mode and related device

Abstract

The present application relates to the field of wireless communication, and in particular to a method for transmitting a beacon frame in an EMLSR mode, which is applied to a wireless local area network supporting the 802.11be standard. The method includes the steps of: a TXOP holder transmitting a first frame before a first delay prior to a next TBTT, the first frame indicating an end of a TXOP on a first link, and the first delay being used by an EMLSR non-AP MLD to change a spatial stream on a second link to a state supporting beacon frame reception on the second link; and the non-AP MLD changing a spatial stream on the second link to a state supporting normal beacon frame reception on the second link within the first delay after the end of a TXOP on the first link, and receiving a beacon frame by using the spatial stream currently supported on the second link at the next TBTT. According to an embodiment of the present application, the non-AP MLD in the EMLSR mode can be prevented from missing an important beacon frame.

Description

[Technical Field]

[0001] This application claims priority to Chinese Patent Application No. 202110462339.3, entitled "Method and Related Apparatus for Transmitting Beacon Frames in EMLSR Mode," filed with the State Intellectual Property Office of China on April 27, 2021, which is incorporated herein by reference in its entirety.

[0002] The present application relates to the field of wireless communication technology, and in particular to a beacon frame transmission method and related device in Enhanced Multi-Link Single Radio (EMLSR) mode. [Background technology]

[0003] A continuing technological goal in the development and evolution of wireless local area networks (WLANs) or cellular networks is to continuously improve throughput. WLAN system protocols are primarily discussed by standards groups within the Institute of Electrical and Electronics Engineers (IEEE). Standards such as IEEE 802.11a / b / g / n / ac / ax have continuously improved throughput. The next-generation WiFi standard, IEEE 802.11be, is called extremely high throughput (EHT) or Wi-Fi 7. A key technology of this standard is improving throughput through the use of multi-link (ML) communication. The core concept of multi-link communication is that WLAN devices supporting the next-generation IEEE 802.11 standard, i.e., EHT devices, have multi-band transmission and reception capabilities, thus using a larger bandwidth for data transmission and significantly improving throughput. Multiple bands include, but are not limited to, the 2.4 GHz WiFi band, the 5 GHz WiFi band, and the 6 GHz WiFi band. A frequency band is called a link, and multiple frequency bands are called multiple links. In 802.11be, a WLAN device that supports multi-link communication is called a multi-link device (MLD). Obviously, a multi-link device can perform parallel communication over multiple links (or multiple frequency bands), which significantly improves the transmission rate. A multi-link device (MLD) includes one or more affiliated stations (STAs). An affiliated station is a logical station that can operate on one link. An affiliated station may be an access point (AP) or a non-access point station (non-AP STA).In the 802.11be standard, a multilink device whose affiliates are APs is called an AP MLD, and a multilink device whose affiliates are non-AP STAs is called a non-AP MLD.

[0004] However, in some cases, there may be stations (STAs) whose reception capabilities are limited. Therefore, the introduction of the enhanced multi-link single radio (EMLSR) mode has been considered, which is mainly applied to non-AP MLD. In this mode, non-AP MLD can only perform a listening operation on the channel to receive initial control frames of orthogonal frequency division multiplexing (OFDM) physical layer protocol data unit (PPDU) type and non-high throughput (HT) duplicate PPDU type from AP MLD; reception of other types of frames is currently not supported. The listening operation is defined as clear channel assessment (CCA).

[0005] The beacon frame is not an initial control frame, and it contains some important information such as critical updates. Therefore, it is recommended that the beacon frame is not missed for non-AP MLD. Therefore, how the non-AP MLD in EMLSR mode receives the beacon frame in listening operation becomes an urgent problem to be solved. Summary of the Invention [Means for solving the problem]

[0006] The embodiments of the present application provide a beacon frame transmission method and related device in EMLSR mode to prevent non-AP MLD in EMLSR mode from missing important beacon frames.

[0007] The following describes the present application from different aspects, and it should be understood that cross-references to the implementations and beneficial effects of the different aspects below may be made.

[0008] According to a first aspect, the present application provides a beacon frame transmission method in an EMLSR mode, the method including: a first link and a second link exist between a TXOP holder AP MLD and an EMLSR non-AP MLD; the AP MLD is to transmit a beacon frame on the second link at a next TBTT; the AP MLD transmits a first frame before a first delay prior to the next TBTT, the first frame indicating an end of the TXOP on the first link; and the AP MLD transmits a beacon frame on the second link at the next TBTT. The first delay is used by the EMLSR non-AP MLD to change a spatial stream on the second link to support beacon frame reception.

[0009] With respect to the first aspect, in one possible implementation, the first delay is one of the following: the first delay is a period of time required for non-AP MLD to change the spatial streams supported on the second link from a single spatial stream to multiple spatial streams; or the first delay is a period of time required for non-AP MLD to change from not supporting spatial streams on the second link to supporting a single spatial stream or multiple spatial streams.

[0010] In this specification, "not supporting spatial streams on the second link" may be understood as the receive antenna in the non-AP MLD not operating on the second link, and therefore no spatial streams exist on the second link.

[0011] Regarding the first aspect, in one possible implementation, the method further includes a step in which the AP MLD receives a second frame, the second frame including indication information, the indication information indicating an identifier of a link whose reception capability is not limited when the non-AP MLD receives by using a single spatial stream.

[0012] Optionally, the indication information is placed in a common information field of the multilink element of the second frame, and the length of the indication information is 4 bits. Optionally, the indication information is placed in an extended multilink capability field of the common information field.

[0013] With regard to the first aspect, in one possible implementation, the method further includes a step in which the AP MLD receives a second frame, the second frame including indication information, the indication information being carried in link information of the link to indicate whether reception capability on the link is limited when a single spatial stream is used for reception.

[0014] Optionally, the indication information is placed in a very high throughput medium access control capability information field of the second frame, and the length of the indication information is 1 bit.

[0015] Optionally, the indication information is placed in a per-station STA profile of the multilink element of the second frame, and the length of the indication information is 1 bit. Optionally, the indication information is placed in a STA control field of the per-station STA profile.

[0016] It should be understood that, because the AP MLD is the TXOP holder, before the AP MLD transmits the first frame, a first delay may need to be determined based on the receiving capabilities on each link when the non-AP MLD receives by using a single spatial stream. In this solution, it may be seen that the non-AP MLD actively reports the link capabilities of the non-AP MLD. When the AP MLD functions as a TXOP holder, beacon frame transmission between the AP MLD and the EMLSR non-AP MLD can be supported. In addition, when communicating with the EMLSR non-AP MLD, the AP MLD may not transmit initial control frames on links where receiving capabilities are not limited, reducing the overhead of some initial control frames.

[0017] Regarding the first aspect, in one possible embodiment, a link whose reception capability is not limited when a non-AP MLD receives by using a single spatial stream is a link over which association request frames and association response frames are exchanged between an AP MLD and a non-AP MLD in an association process, or a link over which re-association request frames and re-association response frames are exchanged between an AP MLD and a non-AP MLD in a re-association process.

[0018] In this solution, a link with unlimited reception capability is agreed upon when the non-AP MLD receives by using a single spatial stream. When the AP MLD acts as a TXOP holder, beacon frame transmission between the AP MLD and the EMLSR non-AP MLD can be supported. In addition, when communicating with the EMLSR non-AP MLD, the AP MLD does not transmit initial control frames on a link with unlimited reception capability, which can reduce the overhead of some initial control frames.

[0019] According to a second aspect, the present application provides a beacon frame transmission method in an EMLSR mode, the method including: a first link and a second link exist between an EMLSR non-AP MLD and a TXOP holder AP MLD; the non-AP MLD receives a first frame before a first delay prior to a next TBTT, the first frame indicating an end of the TXOP on the first link; the non-AP MLD changes spatial streams on the second link to support beacon frame reception within the first delay after the end of the TXOP on the first link; and the non-AP MLD receives a beacon frame by using the spatial streams currently supported on the second link at the next TBTT. The first delay is used by the non-AP MLD to change the spatial streams on the second link to support beacon frame reception.

[0020] In this solution, when the non-AP MLD receives by using a single spatial stream, the impact of the EMLSR switching delay on beacon frame reception is considered separately, and it can be seen that the TXOP holder is restricted to terminate the TXOP before the EMLSR switching delay (i.e., the first delay) prior to the next TBTT, ensuring that the non-AP MLD has enough time to complete the spatial stream change on the second link. This can prevent the non-AP MLD in EMLSR mode from missing important beacon frames.

[0021] Beacon frames contain some important information, such as critical updates, which include TBTT information updates. If a non-AP MLD misses a beacon frame and receives it based on the original (or old) TBTT, the new beacon frame will be missed. In addition, for delivery traffic indication message (DTIM) beacon frames, if a non-AP MLD misses a DTIM beacon frame, the non-AP MLD may miss an opportunity to transmit a downlink data packet. Therefore, it is recommended that beacon frames not be missed for non-AP MLD.

[0022] With respect to the second aspect, in one possible implementation, the first delay is one of the following: the first delay is a period of time required for non-AP MLD to change the spatial streams supported on the second link from a single spatial stream to multiple spatial streams; or the first delay is a period of time required for non-AP MLD to change from not supporting spatial streams on the second link to supporting a single spatial stream or multiple spatial streams.

[0023] Regarding the second aspect, in one possible implementation, reception capability is limited when the non-AP MLD receives on the first link and the second link by using a single spatial stream. Multiple spatial streams are supported on the first link within the TXOP, but no spatial streams are supported on the second link within the TXOP. Changing the spatial streams on the second link to support beacon frame reception by the non-AP MLD within a first delay after the end of the TXOP on the first link includes changing the non-AP MLD from not supporting spatial streams to supporting multiple spatial streams on the second link within a first delay after the end of the TXOP on the first link.

[0024] As referred to herein, "changing from supporting no spatial streams on the second link to supporting multiple spatial streams" may be understood as changing from no receive antennas operating on the second link to multiple receive antennas operating simultaneously on the second link. In other words, the receive antennas in the non-AP MLD are not operating on the second link during the TXOP, and after the TXOP ends, multiple receive antennas are switched to operate on the second link, increasing the number of spatial streams supported on the second link.

[0025] It can be seen that this solution provides a switching solution for cases where the non-AP MLD receives by using a single spatial stream and the receiving capacity on the link is all limited, ensuring that the non-AP MLD can successfully receive the beacon frame at the next TBTT.

[0026] It should be understood that "reception capability is limited" as referred to herein means that only certain types of PPDUs (e.g., OFDM type or non-HT duplicate type) can be received. Correspondingly, "reception capability is not limited" as referred to herein means that all types of PPDUs can be received.

[0027] Regarding the second aspect, in one possible implementation, the non-AP MLD includes a first spatial stream and a second spatial stream, where reception capacity is limited when the non-AP MLD receives on the link by using the first spatial stream, and reception capacity is not limited when the non-AP MLD receives on the link by using the second spatial stream.

[0028] Regarding the second aspect, in one possible implementation, the spatial streams supported on the first link in the TXOP are multiple spatial streams including a first spatial stream and a second spatial stream. However, no spatial streams are supported on the second link of the non-AP MLD in the TXOP. When the non-AP MLD receives on the second link by using a single spatial stream, reception capability is not limited. The step of the non-AP MLD changing the spatial streams on the second link to support beacon frame reception within a first delay after the end of the TXOP on the first link includes changing the non-AP MLD from not supporting spatial streams on the second link to supporting a single spatial stream within the first delay after the end of the TXOP on the first link. The single spatial stream supported on the second link supports beacon frame reception. In this specification, the second spatial stream supported on the first link in the TXOP may be returned to the second link.

[0029] It can be seen that this solution provides a spatial stream switching solution when spatial streams are not supported on the second link and reception capability is not limited when a single spatial stream is used for reception on the second link, ensuring that non-AP MLD can successfully receive the beacon frame at the next TBTT.

[0030] Regarding the second aspect, in one possible implementation, the spatial streams supported on the first link in the TXOP are multiple spatial streams including a first spatial stream and a second spatial stream. However, if the non-AP MLD does not support spatial streams on the second link in the TXOP, and the non-AP MLD performs reception on the second link by using a single spatial stream, reception capability is limited. The step of the non-AP MLD changing the spatial streams on the second link to support beacon frame reception within a first delay after the end of the TXOP on the first link includes the step of: the non-AP MLD changing from not supporting spatial streams on the second link to supporting a single spatial stream within a first delay after the end of the TXOP on the first link. The single spatial stream supported on the second link supports beacon frame reception. In this specification, the second spatial stream supported on the first link may be switched to the second link.

[0031] It can be seen that this solution provides a spatial stream switching solution when spatial streams are not supported on the second link and reception capability is limited when a single spatial stream is used for reception on the second link, ensuring that non-AP MLD can successfully receive the beacon frame at the next TBTT.

[0032] Regarding the second aspect, in one possible implementation, the spatial stream supported on the second link of the non-AP MLD within the TXOP is a single spatial stream, but reception capability is limited when the non-AP MLD receives on the second link by using the single spatial stream. The step of the non-AP MLD changing the spatial stream on the second link to support beacon frame reception within a first delay after the end of the TXOP on the first link includes the step of: the non-AP MLD changing the spatial stream supported on the second link from a single spatial stream to multiple spatial streams within a first delay after the end of the TXOP on the first link.

[0033] It can be seen that this solution provides a spatial stream switching solution when a single spatial stream is originally supported on the second link within the TXOP, but reception capability is limited when a single spatial stream is used for reception on the second link, ensuring that the non-AP MLD can successfully receive the beacon frame at the next TBTT.

[0034] Regarding the second aspect, in one possible implementation, the method further includes a step in which the non-AP MLD transmits a second frame, the second frame including indication information, the indication information indicating an identifier of a link whose reception capability is not limited when the non-AP MLD receives by using a single spatial stream.

[0035] Optionally, the indication information is placed in a common information field of the multilink element of the second frame, and the length of the indication information is 4 bits. Optionally, the indication information is placed in an extended multilink capability field of the common information field.

[0036] Regarding the second aspect, in one possible implementation, the method further includes a step in which the non-AP MLD transmits a second frame, the second frame including indication information, the indication information being carried in link information of the link to indicate whether reception capability on the link is limited when a single spatial stream is used for reception.

[0037] Optionally, the indication information is placed in a Very High Throughput EHT Medium Access Control MAC Capability Information field of the second frame, and the length of the indication information is 1 bit.

[0038] Optionally, the indication information is placed in a per-station STA profile of the multilink element of the second frame, and the length of the indication information is 1 bit. Optionally, the indication information is placed in a STA control field of the per-station STA profile.

[0039] Regarding the second aspect, in one possible embodiment, a link whose reception capability is not limited when a non-AP MLD receives by using a single spatial stream is a link over which association request frames and association response frames are exchanged between an AP MLD and a non-AP MLD in an association process, or a link over which re-association request frames and re-association response frames are exchanged between an AP MLD and a non-AP MLD in a re-association process.

[0040] According to a third aspect, the present application provides a communication device. The communication device may be an AP MLD or a chip within the AP MLD, for example, a Wi-Fi chip. The communication device includes a transceiver unit configured to transmit a first frame before a first delay prior to a next TBTT, where the first frame indicates a TXOP end on a first link and the first delay is used by a non-AP MLD to change a spatial stream on a second link to support beacon frame reception. The transceiver unit is further configured to transmit a beacon frame on the second link at the next TBTT. The first link and a second link exist between the TXOP holder AP MLD and the EMLSR non-AP MLD, and the AP MLD is to transmit a beacon frame on the second link at the next TBTT. Optionally, the communication device further includes a processing unit configured to generate the first frame and the beacon frame.

[0041] With respect to the third aspect, in one possible implementation, the first delay is one of the following: the first delay is a period of time required for non-AP MLD to change the spatial streams supported on the second link from a single spatial stream to multiple spatial streams; or the first delay is a period of time required for non-AP MLD to change from not supporting spatial streams on the second link to supporting a single spatial stream or multiple spatial streams.

[0042] With regard to the third aspect, in one possible implementation, the transceiver unit is configured to receive a second frame, the second frame including indication information, the indication information indicating an identifier of a link whose reception capability is not limited when non-AP MLD performs reception by using a single spatial stream.

[0043] Optionally, the indication information is placed in a common information field of the multilink element of the second frame, and the length of the indication information is 4 bits. Optionally, the indication information is placed in an extended multilink capability field of the common information field.

[0044] With regard to the third aspect, in one possible implementation, the transceiver unit is configured to receive a second frame, the second frame including indication information, the indication information being carried in link information of the link to indicate whether reception capability on the link is limited when a single spatial stream is used for reception.

[0045] Optionally, the indication information is placed in a very high throughput medium access control capability information field of the second frame, and the length of the indication information is 1 bit.

[0046] Optionally, the indication information is placed in a per-station STA profile of the multilink element of the second frame, and the length of the indication information is 1 bit. Optionally, the indication information is placed in a STA control field of the per-station STA profile.

[0047] With regard to the third aspect, in one possible embodiment, a link whose reception capability is not limited when the non-AP MLD receives by using a single spatial stream is a link over which association request frames and association response frames are exchanged between the communication device and the non-AP MLD in the association process, or a link over which reassociation request frames and reassociation response frames are exchanged between the communication device and the non-AP MLD in the reassociation process.

[0048] According to a fourth aspect, the present application provides a communication device. The communication device may be a non-AP MLD or a chip within the non-AP MLD, for example, a Wi-Fi chip. The communication device includes: a transceiver unit configured to receive a first frame before a first delay prior to a next TBTT, where the first frame indicates a TXOP end on a first link, and the first delay is used by the non-AP MLD to change spatial streams on a second link to support beacon frame reception; and a processing unit configured to change spatial streams on the second link to support beacon frame reception within the first delay after the TXOP end on the first link. The transceiver unit is further configured to receive a beacon frame by using spatial streams currently supported on the second link at the next TBTT. A first link and a second link exist between the communication device and the TXOP holder AP MLD.

[0049] With respect to the fourth aspect, in one possible implementation, the first delay is one of the following: the first delay is a period of time required for non-AP MLD to change the spatial streams supported on the second link from a single spatial stream to multiple spatial streams; or the first delay is a period of time required for non-AP MLD to change from not supporting spatial streams on the second link to supporting a single spatial stream or multiple spatial streams.

[0050] Regarding the fourth aspect, in one possible implementation, reception capability is limited when non-AP MLD receives on a first link and a second link by using a single spatial stream, where multiple spatial streams are supported on the first link within a TXOP, but no spatial streams are supported on the second link for non-AP MLD within the TXOP, and the processing unit is specifically configured to change from supporting no spatial streams to supporting multiple spatial streams on the second link within a first delay after the end of the TXOP on the first link.

[0051] Regarding the fourth aspect, in one possible implementation, the non-AP MLD includes a first spatial stream and a second spatial stream, where reception capacity is limited when the non-AP MLD receives on the link by using the first spatial stream, and reception capacity is not limited when the non-AP MLD receives on the link by using the second spatial stream.

[0052] Regarding the fourth aspect, in one possible implementation, the spatial streams supported on the first link in the TXOP are multiple spatial streams including a first spatial stream and a second spatial stream. However, no spatial streams are supported on the second link in the non-AP MLD in the TXOP. When the non-AP MLD receives on the second link by using a single spatial stream, the reception capability is not limited. The processing unit is specifically configured to change the second link from supporting no spatial streams to supporting a single spatial stream within a first delay after the end of the TXOP on the first link. The single spatial stream supported on the second link supports beacon frame reception. In this specification, the second spatial stream supported on the first link in the TXOP may be returned to the second link.

[0053] Regarding the fourth aspect, in one possible implementation, the spatial streams supported on the first link in the TXOP are multiple spatial streams including a first spatial stream and a second spatial stream. However, no spatial streams are supported on the second link of the non-AP MLD in the TXOP, and reception capability is limited when the non-AP MLD receives on the second link by using a single spatial stream. The processing unit is specifically configured to change from supporting no spatial streams to supporting a single spatial stream on the second link within a first delay after the end of the TXOP on the first link. The single spatial stream supported on the second link supports beacon frame reception. In this specification, the second spatial stream supported on the first link may be switched to the second link.

[0054] Regarding the fourth aspect, in one possible implementation, the spatial stream supported on the second link of the non-AP MLD in the TXOP is a single spatial stream, but reception capability is limited when the non-AP MLD receives on the second link by using the single spatial stream, and the processing unit is specifically configured to change the spatial stream supported on the second link from a single spatial stream to multiple spatial streams within a first delay after the end of the TXOP on the first link.

[0055] Regarding the fourth aspect, in one possible implementation, the transceiver unit is further configured to transmit a second frame, the second frame including indication information, and the indication information indicating an identifier of a link whose reception capability is not limited when non-AP MLD performs reception by using a single spatial stream.

[0056] Optionally, the indication information is placed in a common information field of the multilink element of the second frame, and the length of the indication information is 4 bits. Optionally, the indication information is placed in an extended multilink capability field of the common information field.

[0057] With regard to the fourth aspect, in one possible implementation, the transceiver unit is configured to transmit a second frame, the second frame including indication information, the indication information being carried in link information of the link to indicate whether reception capability on the link is limited when a single spatial stream is used for reception.

[0058] Optionally, the indication information is placed in a very high throughput medium access control capability information field of the second frame, and the length of the indication information is 1 bit.

[0059] Optionally, the indication information is placed in a per-station STA profile of the multilink element of the second frame, and the length of the indication information is 1 bit. Optionally, the indication information is placed in a STA control field of the per-station STA profile.

[0060] Regarding the fourth aspect, in one possible embodiment, a link whose reception capability is not limited when a non-AP MLD receives by using a single spatial stream is a link over which association request frames and association response frames are exchanged between an AP MLD and a non-AP MLD in an association process, or a link over which re-association request frames and re-association response frames are exchanged between an AP MLD and a non-AP MLD in a re-association process.

[0061] According to a fifth aspect, the present application provides a beacon frame transmission method in EMLSR mode, the method including: a first link and a second link exist between a TXOP holder non-AP MLD and an AP MLD; the non-AP MLD transmits a first frame before a first delay prior to a next TBTT, the first frame indicating the end of the TXOP on the first link; the non-AP MLD changes spatial streams on the second link to support beacon frame reception within the first delay after the end of the TXOP on the first link; and the non-AP MLD receives a beacon frame by using the spatial streams currently supported on the second link at the next TBTT. The first delay is used by the non-AP MLD to change the spatial streams on the second link to support beacon frame reception. The non-AP MLD is in EMLSR mode.

[0062] In this solution, for the case where a non-AP MLD acts as a TXOP holder, it can be seen that when the non-AP MLD receives by using a single spatial stream, the impact of the EMLSR switching delay on beacon frame reception is considered separately, and the TXOP holder is restricted to terminate the TXOP before the EMLSR switching delay (i.e., the first delay) prior to the next TBTT, ensuring that the non-AP MLD has enough time to complete spatial stream switching on the second link. This can prevent the non-AP MLD in EMLSR mode from missing important beacon frames.

[0063] With respect to the fifth aspect, in one possible implementation, the first delay is one of the following: the first delay is a period of time required for non-AP MLD to change the spatial streams supported on the second link from a single spatial stream to multiple spatial streams; or the first delay is a period of time required for non-AP MLD to change from not supporting spatial streams on the second link to supporting a single spatial stream or multiple spatial streams.

[0064] Regarding the fifth aspect, in one possible implementation, reception capability is limited when the non-AP MLD receives on the first link and the second link by using a single spatial stream. Multiple spatial streams are supported on the first link within the TXOP, but no spatial streams are supported on the second link within the TXOP. Changing the spatial streams on the second link to support beacon frame reception by the non-AP MLD within a first delay after the end of the TXOP on the first link includes changing the non-AP MLD from not supporting spatial streams to supporting multiple spatial streams on the second link within a first delay after the end of the TXOP on the first link.

[0065] Regarding the fifth aspect, in one possible implementation, the non-AP MLD includes a first spatial stream and a second spatial stream, where reception capacity is limited when the non-AP MLD receives on the link by using the first spatial stream, and reception capacity is not limited when the non-AP MLD receives on the link by using the second spatial stream.

[0066] Regarding the fifth aspect, in one possible implementation, the spatial streams supported on the first link in the TXOP are multiple spatial streams including a first spatial stream and a second spatial stream. However, no spatial streams are supported on the second link of the non-AP MLD in the TXOP. When the non-AP MLD receives on the second link by using a single spatial stream, reception capability is not limited. The step of the non-AP MLD changing the spatial streams on the second link to support beacon frame reception within a first delay after the end of the TXOP on the first link includes the step of the non-AP MLD changing from not supporting spatial streams on the second link to supporting a single spatial stream within a first delay after the end of the TXOP on the first link. The single spatial stream supported on the second link supports beacon frame reception. In this specification, the second spatial stream supported on the first link in the TXOP may be returned to the second link.

[0067] Regarding the fifth aspect, in one possible implementation, the spatial streams supported on the first link in the TXOP are multiple spatial streams including a first spatial stream and a second spatial stream. However, if the non-AP MLD does not support spatial streams on the second link in the TXOP, and the non-AP MLD performs reception on the second link by using a single spatial stream, reception capability is limited. The step of the non-AP MLD changing the spatial streams on the second link to support beacon frame reception within a first delay after the end of the TXOP on the first link includes the step of: the non-AP MLD changing from not supporting spatial streams on the second link to supporting a single spatial stream within a first delay after the end of the TXOP on the first link. The single spatial stream supported on the second link supports beacon frame reception. In this specification, the second spatial stream supported on the first link may be switched to the second link.

[0068] Regarding the fifth aspect, in one possible implementation, the spatial stream supported on the second link of the non-AP MLD within the TXOP is a single spatial stream, but reception capability is limited when the non-AP MLD receives on the second link by using the single spatial stream. The step of the non-AP MLD changing the spatial stream on the second link to support beacon frame reception within a first delay after the end of the TXOP on the first link includes the step of: the non-AP MLD changing the spatial stream supported on the second link from a single spatial stream to multiple spatial streams within a first delay after the end of the TXOP on the first link.

[0069] With regard to the fifth aspect, in one possible embodiment, a link whose reception capability is not limited when a non-AP MLD receives by using a single spatial stream is a link over which association request frames and association response frames are exchanged between an AP MLD and a non-AP MLD in an association process, or a link over which re-association request frames and re-association response frames are exchanged between an AP MLD and a non-AP MLD in a re-association process.

[0070] According to a sixth aspect, the present application provides a beacon frame transmission method in an EMLSR mode, the method including: a first link and a second link exist between an AP MLD and a TXOP holder non-AP MLD; the AP MLD receives a first frame before a first delay prior to a next TBTT, the first frame indicating an end of a TXOP on the first link; and the AP MLD transmits a beacon frame on the second link at the next TBTT. The first delay is used by the EMLSR non-AP MLD to change a spatial stream on the second link to support beacon frame reception.

[0071] With respect to the sixth aspect, in one possible implementation, the first delay is one of the following: the first delay is a period of time required for non-AP MLD to change the spatial streams supported on the second link from a single spatial stream to multiple spatial streams; or the first delay is a period of time required for non-AP MLD to change from not supporting spatial streams on the second link to supporting a single spatial stream or multiple spatial streams.

[0072] Regarding the sixth aspect, in one possible embodiment, a link whose reception capability is not limited when a non-AP MLD receives by using a single spatial stream is a link over which association request frames and association response frames are exchanged between an AP MLD and a non-AP MLD in an association process, or a link over which re-association request frames and re-association response frames are exchanged between an AP MLD and a non-AP MLD in a re-association process.

[0073] According to a seventh aspect, the present application provides a communication device. The communication device may be a non-AP MLD or a chip within the non-AP MLD, such as a Wi-Fi chip. The communication device includes: a transceiver unit configured to transmit a first frame before a first delay prior to a next TBTT, where the first frame indicates the end of a TXOP on a first link, and the first delay is used by the non-AP MLD to change a spatial stream on a second link to support beacon frame reception; and a processing unit configured to change the spatial stream on the second link to support beacon frame reception within the first delay after the end of the TXOP on the first link. The transceiver unit is further configured to receive a beacon frame by using the spatial stream currently supported on the second link at the next TBTT. A first link and a second link exist between the non-AP MLD and a TXOP holder AP MLD. The non-AP MLD is in EMLSR mode.

[0074] With respect to the seventh aspect, in one possible implementation, the first delay is one of the following: the first delay is a period of time required for non-AP MLD to change the spatial streams supported on the second link from a single spatial stream to multiple spatial streams; or the first delay is a period of time required for non-AP MLD to change from not supporting spatial streams on the second link to supporting a single spatial stream or multiple spatial streams.

[0075] Regarding the seventh aspect, in one possible implementation, reception capability is limited when non-AP MLD receives on a first link and a second link by using a single spatial stream. Multiple spatial streams are supported on the first link within a TXOP, but no spatial streams are supported on the second link for non-AP MLD within the TXOP. The processing unit is specifically configured to change from supporting no spatial streams to supporting multiple spatial streams on the second link within a first delay after the end of the TXOP on the first link.

[0076] Regarding the seventh aspect, in one possible implementation, the non-AP MLD includes a first spatial stream and a second spatial stream, and reception capacity is limited when the non-AP MLD receives on the link by using the first spatial stream, and reception capacity is not limited when the non-AP MLD receives on the link by using the second spatial stream.

[0077] Regarding the seventh aspect, in one possible implementation, the spatial streams supported on the first link in the TXOP are multiple spatial streams including a first spatial stream and a second spatial stream. However, no spatial streams are supported on the second link in the non-AP MLD in the TXOP. When the non-AP MLD receives on the second link by using a single spatial stream, the reception capability is not limited. The processing unit is specifically configured to change the second link from supporting no spatial streams to supporting a single spatial stream within a first delay after the end of the TXOP on the first link. The single spatial stream supported on the second link supports beacon frame reception. In this specification, the second spatial stream supported on the first link in the TXOP may be returned to the second link.

[0078] Regarding the seventh aspect, in one possible implementation, the spatial streams supported on the first link in the TXOP are multiple spatial streams including a first spatial stream and a second spatial stream. However, if no spatial streams are supported on the second link of the non-AP MLD in the TXOP, and the non-AP MLD performs reception on the second link by using a single spatial stream, reception capability is limited. The processing unit is specifically configured to change from supporting no spatial streams to supporting a single spatial stream on the second link within a first delay after the end of the TXOP on the first link. The single spatial stream supported on the second link supports beacon frame reception. In this specification, the second spatial stream supported on the first link may be switched to the second link.

[0079] Regarding the seventh aspect, in one possible implementation, the spatial stream supported on the second link of the non-AP MLD in the TXOP is a single spatial stream, but reception capability is limited when the non-AP MLD receives on the second link by using the single spatial stream, and the processing unit is specifically configured to change the spatial stream supported on the second link from a single spatial stream to multiple spatial streams within a first delay after the end of the TXOP on the first link.

[0080] With regard to the seventh aspect, in one possible embodiment, a link whose reception capability is not limited when a non-AP MLD receives by using a single spatial stream is a link over which association request frames and association response frames are exchanged between an AP MLD and a non-AP MLD in an association process, or a link over which re-association request frames and re-association response frames are exchanged between an AP MLD and a non-AP MLD in a re-association process.

[0081] According to an eighth aspect, the present application provides a communication device. The communication device may be an AP MLD or a chip within the AP MLD, for example, a Wi-Fi chip. The communication device includes a transceiver unit configured to receive a first frame before a first delay prior to a next TBTT, where the first frame indicates a TXOP end on a first link, and the first delay is used by a non-AP MLD to change a spatial stream on a second link to support beacon frame reception. The transceiver unit is further configured to transmit a beacon frame on the second link at the next TBTT. The first link and the second link exist between the AP MLD and the TXOP holder non-AP MLD, and the non-AP MLD is in EMLSR mode. Optionally, the communication device further includes a processing unit configured to generate a beacon frame.

[0082] With respect to the eighth aspect, in one possible implementation, the first delay is one of the following: the first delay is a period of time required for non-AP MLD to change the spatial streams supported on the second link from a single spatial stream to multiple spatial streams; or the first delay is a period of time required for non-AP MLD to change from not supporting spatial streams on the second link to supporting a single spatial stream or multiple spatial streams.

[0083] With regard to the eighth aspect, in one possible embodiment, a link whose reception capability is not limited when a non-AP MLD receives by using a single spatial stream is a link over which association request frames and association response frames are exchanged between an AP MLD and a non-AP MLD in an association process, or a link over which re-association request frames and re-association response frames are exchanged between an AP MLD and a non-AP MLD in a re-association process.

[0084] According to a ninth aspect, the present application provides a beacon frame transmission method in an EMLSR mode, the method including: a first link exists between an EMLSR non-AP MLD and a TXOP holder AP MLD, and the non-AP MLD receives a first frame prior to a next TBTT, the first frame indicating an end of a TXOP on the first link; and the non-AP MLD maintains spatial streams supported on the first link and receives a beacon frame by using the spatial streams supported on the first link at the next TBTT. The spatial streams supported on the first link are a single spatial stream or multiple spatial streams.

[0085] According to a tenth aspect, the present application provides a communication device. The communication device may be a non-AP MLD or a chip within the non-AP MLD, such as a Wi-Fi chip. The communication device includes a transceiver unit configured to receive a first frame prior to a next TBTT, where the first frame indicates a TXOP end on a first link, and a processing unit configured to maintain spatial streams supported on the first link. The transceiver unit is further configured to receive a beacon frame by using the spatial streams supported on the first link at the next TBTT. The spatial streams supported on the first link may be a single spatial stream or multiple spatial streams.

[0086] It can be understood that since the link related to the current TXOP and the link for transmitting a beacon frame in the next TBTT are the same link and the reception capability of non-AP MLD is not limited on the link related to the TXOP, non-AP MLD can maintain the current spatial stream and successfully receive a beacon frame in the next TBTT, which can prevent non-AP MLD in EMLSR mode from missing important beacon frames.

[0087] According to an eleventh aspect, the present application provides a link capability indication method in EMLSR mode, the method including: generating and transmitting a medium access control (MAC) frame, the MAC frame including indication information, the indication information indicating an identifier of a link whose receiving capability is not limited when non-AP MLD performs reception by using a single spatial stream.

[0088] In this solution, it can be seen that the non-AP MLD actively reports the link capabilities of the non-AP MLD. When the AP MLD acts as a TXOP holder, beacon frame transmission between the AP MLD and the EMLSR non-AP MLD can be supported. In addition, when communicating with the EMLSR non-AP MLD, the AP MLD does not transmit initial control frames on links where reception capabilities are not limited, which can reduce the overhead of some initial control frames.

[0089] According to a twelfth aspect, the present application provides a link capability indication method in an EMLSR mode, the method including: a step of an AP MLD receiving a MAC frame, the MAC frame including indication information, the indication information indicating an identifier of a link whose reception capability is not limited when a non-AP MLD receives by using a single spatial stream; and a step of the AP MLD parsing the MAC frame to determine the link whose reception capability is not limited when a non-AP MLD receives by using a single spatial stream.

[0090] According to a thirteenth aspect, the present application provides a communication device. The communication device may be a non-AP MLD or a chip in the non-AP MLD, such as a Wi-Fi chip. The communication device includes: a processing unit configured to generate a MAC frame, the MAC frame including indication information, the indication information indicating an identifier of a link whose reception capability is not limited when the non-AP MLD performs reception by using a single spatial stream; and a transceiver unit configured to transmit the MAC frame.

[0091] According to a fourteenth aspect, the present application provides a communication device. The communication device may be an AP MLD or a chip within the AP MLD, such as a Wi-Fi chip. The communication device includes: a transceiver unit configured to receive a MAC frame, the MAC frame including indication information, the indication information indicating an identifier of a link whose reception capability is not limited when a non-AP MLD receives by using a single spatial stream; and a processing unit configured to parse the MAC frame to determine the link whose reception capability is not limited when the non-AP MLD receives by using a single spatial stream.

[0092] In one possible implementation of the eleventh to fourteenth aspects, the indication information is placed in a common information field of a multilink element of the second frame, and the length of the indication information is 4 bits. Optionally, the indication information is placed in an extended multilink capability field of the common information field.

[0093] According to a fifteenth aspect, the present application provides a link capability indication method in EMLSR mode, the method including: a step in which a non-AP MLD generates and transmits a MAC frame, the MAC frame including indication information, the indication information being carried in link information of a link in the MAC frame to indicate whether reception capability on the link is limited when a single spatial stream is used for reception.

[0094] According to a sixteenth aspect, the present application provides a link capability indication method in an EMLSR mode, the method including: a step of an AP MLD receiving a MAC frame, the MAC frame including indication information, the indication information being carried in link information of a link in the MAC frame to indicate whether reception capability on the link is limited when a single spatial stream is used for reception; and a step of the AP MLD parsing the MAC frame to determine whether reception capability on the link is limited when a single spatial stream is used for reception.

[0095] According to a seventeenth aspect, the present application provides a communication device, which may be a non-AP MLD or a chip in the non-AP MLD, such as a Wi-Fi chip, including: a processing unit configured to generate a MAC frame, the MAC frame including indication information, the indication information being carried in link information of a link in the MAC frame to indicate whether reception capability on the link is limited when a single spatial stream is used for reception; and a transceiver unit configured to transmit the MAC frame.

[0096] According to an eighteenth aspect, the present application provides a communication device. The communication device may be an AP MLD or a chip in the AP MLD, such as a Wi-Fi chip. The communication device includes: a transceiver unit configured to receive a MAC frame, the MAC frame including indication information, the indication information being carried in link information of a link in the MAC frame to indicate whether reception capability on the link is limited when a single spatial stream is used for reception; and a processing unit configured to parse the MAC frame to determine whether reception capability on the link is limited when a single spatial stream is used for reception.

[0097] In one possible implementation of the fifteenth to eighteenth aspects, the indication information is placed in an ultra-high throughput medium access control capability information field of the second frame, and the length of the indication information is 1 bit.

[0098] According to a 19th aspect, the present application provides a non-trigger-based data transmission method for uplink in EMLSR mode, the method including: a step in which a non-AP MLD performs channel contention on a first link to obtain a TXOP, where a spatial stream on the first link is a single spatial stream; a step in which the non-AP MLD maintains channel occupancy on the first link and switches a spatial stream on a second link to the first link to form multiple spatial streams; and a step in which the non-AP MLD transmits an uplink PPDU on the first link by using the multiple spatial streams.

[0099] In this embodiment of the present application, it can be seen that non-AP MLD in EMLSR mode is supported to transmit uplink data in a non-trigger-based manner, since non-AP MLD in EMLSR mode is further enabled to perform autonomous contention.

[0100] According to a twentieth aspect, the present application provides a communication device. The communication device may be a non-AP MLD or a chip in the non-AP MLD, such as a Wi-Fi chip. The communication device includes: a processing unit configured to perform channel contention on a first link to obtain a TXOP, where a spatial stream on the first link is a single spatial stream, and the processing unit is further configured to maintain channel occupancy on the first link and switch a spatial stream on a second link to the first link to form multiple spatial streams; and a transceiver unit configured to transmit an uplink PPDU on the first link by using the multiple spatial streams.

[0101] According to a twenty-first aspect, the present application provides a communication device, specifically an AP MLD, including a processor and a transceiver.

[0102] In one design, the transceiver is configured to transmit a first frame before a first delay prior to a next TBTT, where the first frame indicates a TXOP end on the first link and the first delay is used by the non-AP MLD to change spatial streams on the second link to support beacon frame reception. The transceiver is further configured to transmit a beacon frame on the second link at the next TBTT. The first link and the second link exist between the TXOP holder AP MLD and the EMLSR non-AP MLD, and the AP MLD is to transmit a beacon frame on the second link at the next TBTT. Optionally, the processor is configured to generate the first frame and the beacon frame.

[0103] In one design, the transceiver is configured to receive a first frame before a first delay prior to a next TBTT, the first frame indicating a TXOP termination on the first link, and the first delay being used by the non-AP MLD to change spatial streams on the second link to support beacon frame reception. The transceiver is further configured to transmit a beacon frame on the second link at the next TBTT. The first link and the second link exist between the AP MLD and the TXOP holder non-AP MLD, and the non-AP MLD is in EMLSR mode. Optionally, the processor is configured to generate a beacon frame.

[0104] In one design, the transceiver is configured to receive a MAC frame, the MAC frame including indication information, the indication information indicating identifiers of links whose reception capabilities are not limited when non-AP MLD receives by using a single spatial stream, and the processor is configured to parse the MAC frame to determine the links whose reception capabilities are not limited when non-AP MLD receives by using a single spatial stream.

[0105] In one design, the transceiver is configured to receive a MAC frame, the MAC frame including indication information, the indication information being carried in link information of a link within the MAC frame to indicate whether reception capability on the link is limited when a single spatial stream is used for reception, and the processor is configured to parse the MAC frame to determine whether reception capability on the link is limited when a single spatial stream is used for reception.

[0106] According to a twenty-second aspect, the present application provides a communication device, specifically an AP MLD, including a processor and a transceiver.

[0107] In one design, the transceiver is configured to receive a first frame before a first delay prior to a next TBTT, the first frame indicating TXOP termination on the first link, the first delay being used by the non-AP MLD to change spatial streams on the second link to support beacon frame reception, and the processor is configured to change spatial streams on the second link to support beacon frame reception within the first delay after the TXOP termination on the first link. The transceiver is further configured to receive a beacon frame by using the spatial streams currently supported on the second link at the next TBTT. The first link and the second link exist between the non-AP MLD and the TXOP holder AP MLD.

[0108] In one design, the transceiver is configured to transmit a first frame before a first delay prior to a next TBTT, the first frame indicating the end of a TXOP on the first link, the first delay being used by the non-AP MLD to change spatial streams on the second link to support beacon frame reception, and the processor is configured to change the spatial streams on the second link to support beacon frame reception within the first delay after the end of the TXOP on the first link. The transceiver is further configured to receive a beacon frame by using the spatial streams currently supported on the second link at the next TBTT. The first link and the second link exist between the non-AP MLD and the TXOP holder AP MLD. The non-AP MLD is in EMLSR mode.

[0109] In one design, the transceiver is configured to receive a first frame prior to a next TBTT, the first frame indicating an end of a TXOP on the first link, and the processor is configured to maintain supported spatial streams on the first link. The transceiver is further configured to receive a beacon frame by using the supported spatial streams on the first link at the next TBTT. The supported spatial streams on the first link are a single spatial stream or multiple spatial streams.

[0110] In one design, the processor is configured to generate a MAC frame, the MAC frame including indication information, the indication information indicating an identifier of a link whose reception capability is not limited when non-AP MLD receives by using a single spatial stream, and the transceiver is configured to transmit the MAC frame.

[0111] In one design, the processor is configured to generate a MAC frame, the MAC frame including indication information, the indication information being carried in link information of a link within the MAC frame to indicate whether reception capability on the link is limited when a single spatial stream is used for reception, and the transceiver is configured to transmit the MAC frame.

[0112] In one design, the processor is configured to perform channel contention on a first link to obtain a TXOP, and the spatial stream on the first link is a single spatial stream, and the processor is further configured to maintain channel occupancy on the first link and switch the spatial stream on the second link to the first link to form multiple spatial streams. The transceiver is configured to transmit an uplink PPDU on the first link using the multiple spatial streams.

[0113] According to a twenty-third aspect, the present application provides an apparatus, the apparatus being implemented in the form of a chip product and including an input / output interface and a processing circuit, the apparatus being a chip in an AP MLD.

[0114] In one design, the input / output interface is configured to output a first frame before a first delay prior to a next TBTT, process the first frame by using the radio frequency circuitry, and transmit the first frame by using the antenna, the first frame indicating a TXOP end on the first link, and the first delay is used by non-AP MLD to modify spatial streams on the second link to support beacon frame reception. The input / output interface is further configured to output a beacon frame at the next TBTT, process the beacon frame by using the radio frequency circuitry, and transmit the beacon frame on the second link by using the antenna. Optionally, the processing circuit is configured to generate the first frame and the beacon frame.

[0115] In one design, the input / output interface is configured to input a first frame received by using the antenna and the radio frequency circuitry prior to a next TBTT, the first frame indicating a TXOP termination on the first link, and the first delay being used by non-AP MLD to modify spatial streams on the second link to support beacon frame reception. The input / output interface is further configured to output a beacon frame at the next TBTT, process the beacon frame by using the radio frequency circuitry, and transmit the beacon frame on the second link by using the antenna. Optionally, the processing circuitry is configured to generate the beacon frame.

[0116] In one design, the input / output interface is configured to input a MAC frame received by using the antenna and the radio frequency circuitry, the MAC frame including indication information, the indication information indicating an identifier of a link whose reception capability is not limited when the non-AP MLD receives by using a single spatial stream, and the processing circuitry is configured to parse the MAC frame to determine the link whose reception capability is not limited when the non-AP MLD receives by using a single spatial stream.

[0117] In one design, the input / output interface is configured to input a MAC frame received by using the antenna and the radio frequency circuitry, the MAC frame including indication information, the indication information being carried in link information of a link in the MAC frame to indicate whether reception capability on the link is limited when a single spatial stream is used for reception, and the processing circuitry is configured to parse the MAC frame to determine whether reception capability on the link is limited when a single spatial stream is used for reception.

[0118] According to a twenty-fourth aspect, the present application provides an apparatus. The apparatus is implemented in the form of a chip product and includes an input / output interface and a processing circuit. The apparatus is a chip in a non-AP MLD.

[0119] In one design, the input / output interface is configured to input a first frame received using the antenna and radio frequency circuitry before a first delay prior to a next TBTT, the first frame indicating a TXOP end on the first link, the first delay being used by non-AP MLD to change spatial streams on the second link to support beacon frame reception, and the processing circuitry is configured to change the spatial streams on the second link to support beacon frame reception within the first delay after the TXOP end on the first link. The input / output interface is configured to input the beacon frame received using the antenna and radio frequency circuitry by using the spatial stream currently supported on the second link at the next TBTT.

[0120] In one design, the input / output interface is configured to output a first frame before a first delay prior to a next TBTT, process the first frame using the radio frequency circuitry, transmit the first frame using the antenna, the first frame indicating a TXOP end on the first link, and the first delay is used to change spatial streams on the second link to support beacon frame reception by non-AP MLD. The processing circuitry is configured to change spatial streams on the second link to support beacon frame reception within the first delay after the TXOP end on the first link. The input / output interface is further configured to input the beacon frame received using the antenna and the radio frequency circuitry by using the spatial stream currently supported on the second link at the next TBTT.

[0121] In one design, the input / output interface is configured to input a first frame received using the antenna and radio frequency circuitry prior to a next TBTT, the first frame indicating a TXOP termination on the first link. The processing circuitry is configured to maintain supported spatial streams on the first link. The input / output interface is configured to input a beacon frame received using the antenna and radio frequency circuitry by using the supported spatial streams on the first link at the next TBTT. The supported spatial streams on the first link are a single spatial stream or multiple spatial streams.

[0122] In one design, the processing circuitry is configured to generate a MAC frame, the MAC frame including indication information, the indication information indicating an identifier of a link whose reception capability is not limited when non-AP MLD receives by using a single spatial stream. The input / output interface is configured to output the MAC frame, process the MAC frame by using the radio frequency circuitry, and transmit the MAC frame by using the antenna.

[0123] In one design, the processing circuitry is configured to generate a MAC frame, and the indication information is carried in link information of the link in the MAC frame to indicate whether reception capability on the link is limited when a single spatial stream is used for reception. The input / output interface is configured to output the MAC frame, process the MAC frame by using the radio frequency circuitry, and transmit the MAC frame by using the antenna.

[0124] In one design, the processing circuitry is configured to perform channel contention on a first link to obtain a TXOP, and the spatial stream on the first link is a single spatial stream. The processing circuitry is further configured to maintain channel occupancy on the first link and switch the spatial stream on the second link to the first link to form multiple spatial streams. The input / output interface is configured to output an uplink PPDU, process the uplink PPDU by using the radio frequency circuitry, and transmit the uplink PPDU on the first link by using the multiple spatial streams, using the antenna.

[0125] According to a twenty-fifth aspect, the present application provides a computer-readable storage medium having stored thereon program instructions that, when executed on a computer, enable the computer to perform a beacon frame transmission method in EMLSR mode according to the first, second, fifth, sixth, or ninth aspect.

[0126] According to a twenty-sixth aspect, the present application provides a computer-readable storage medium having stored thereon program instructions that, when executed on a computer, enable the computer to perform the link capability indication method in EMLSR mode according to the eleventh or fifteenth aspect.

[0127] According to a twenty-seventh aspect, the present application provides a computer-readable storage medium having stored thereon program instructions that, when executed on a computer, enable the computer to perform the method for uplink non-trigger-based data transmission in EMLSR mode according to the nineteenth aspect.

[0128] According to a twenty-eighth aspect, the present application provides a computer program product including program instructions, which, when run on a computer, enable the computer to perform a beacon frame transmission method in EMLSR mode according to the first, second, fifth, sixth or ninth aspect.

[0129] According to a 29th aspect, the present application provides a computer program product including program instructions, which, when run on a computer, enable the computer to perform the link capability indication method in EMLSR mode according to the 11th or 15th aspect.

[0130] According to a 30th aspect, the present application provides a computer program product including program instructions that, when run on a computer, enable the computer to perform the method for uplink non-trigger-based data transmission in EMLSR mode according to the 19th aspect.

[0131] According to an embodiment of the present application, non-AP MLD in EMLSR mode can be prevented from missing important beacon frames.

[0132] To describe the technical solutions of the embodiments of the present application more clearly, the following briefly describes the accompanying drawings used to describe the embodiments. [Brief explanation of the drawings]

[0133] [Figure 1] 1 is a schematic diagram illustrating the architecture of a wireless communication system according to an embodiment of the present application; [Figure 2a] FIG. 1 is a schematic diagram illustrating the structure of a multi-link device according to an embodiment of the present application. [Figure 2b] FIG. 10 is a schematic diagram illustrating another structure of a multi-link device according to an embodiment of the present application. [Figure 3]FIG. 1 is a schematic diagram of multi-link communication according to an embodiment of the present application; [Figure 4] 1 is a schematic diagram of communication between non-AP MLD and AP MLD in EMLSR mode. [Figure 5] 2 is a schematic flowchart of a beacon frame transmission method in EMLSR mode according to an embodiment of the present application; [Figure 6] 1 is a sequence diagram of beacon frame transmission when the receiving capabilities between links are asymmetric according to an embodiment of the present application; [Figure 7a] 2 is a sequence diagram of beacon frame transmission when the receiving capabilities between links are asymmetric according to an embodiment of the present application; [Figure 7b] 3 is a sequence diagram of beacon frame transmission when the receiving capabilities between links are asymmetric according to an embodiment of the present application; [Figure 8] FIG. 4 is a sequence diagram of beacon frame transmission when the receiving capabilities between links are asymmetric according to an embodiment of the present application. [Figure 9] FIG. 2 is a sequence diagram of beacon frame transmission when the receiving capabilities between links are symmetrical according to an embodiment of the present application; [Figure 10] 10 is another schematic flowchart of a beacon frame transmitting method in EMLSR mode according to an embodiment of the present application; [Figure 11] 3 is a schematic flowchart of a method for indicating link capability in EMLSR mode according to an embodiment of the present application; [Figure 12] FIG. 2 is a schematic diagram of a frame format of an EHT MAC capability information field according to an embodiment of the present application; [Figure 13] 1 is a schematic diagram of a frame format of a STA control field according to an embodiment of the present application; [Figure 14] FIG. 2 is a schematic diagram of a frame format of an EML capability field according to an embodiment of the present application. [Figure 15]2 is a schematic flowchart of an uplink non-trigger-based data transmission method in EMLSR mode according to an embodiment of the present application; [Figure 16a] FIG. 1 is a sequence diagram of an uplink non-trigger-based data transmission method according to an embodiment of the present application; [Figure 16b] FIG. 2 is a sequence diagram of an uplink non-trigger-based data transmission method according to an embodiment of the present application; [Figure 16c] FIG. 3 is a sequence diagram of an uplink non-trigger-based data transmission method according to an embodiment of the present application; [Figure 17] 1 is a schematic diagram illustrating the structure of a communication device 1 according to an embodiment of the present application. [Figure 18] 1 is a schematic diagram illustrating the structure of a communication device 2 according to an embodiment of the present application. [Figure 19] 1 is a schematic diagram illustrating the structure of a communication device 1000 according to an embodiment of the present application. DETAILED DESCRIPTION OF THE INVENTION

[0134] The following clearly and completely describes the technical solutions in the embodiments of the present application with reference to the accompanying drawings in the embodiments of the present application.

[0135] In order to clearly describe the technical solutions of the embodiments of the present application, terms such as "first" and "second" are used in the embodiments of the present application to distinguish between the same or similar items that basically provide the same function or purpose. For example, the first link and the second link are only used to distinguish between different information and do not limit the order. Those skilled in the art can understand that terms such as "first" and "second" do not limit the quantity or execution order, and terms such as "first" and "second" do not indicate a clear difference.

[0136] In the description of this application, unless otherwise specified, " / " generally indicates an "or" relationship between related objects. For example, A / B may indicate A or B. The term "and / or" in this specification merely describes the relationship of association for describing related objects and indicates that three relationships may exist. For example, A and / or B refers to the following three cases: when only A is present, when both A and B are present, and when only B is present. In addition, "at least one" means one or more, and "multiple" means two or more. "At least one of" or similar expressions indicates any combination of these things, including any combination of a single thing or multiple things. For example, "at least one of a, b, and c" may refer to a, b, c, a and b, a and c, b and c, or a, b, and c. Each of a, b, and c may be singular or plural.

[0137] In this application, words such as "example" and "for example" are used to indicate giving an example, illustrative example, or illustration. The use of "example" or "for example" in this application should not be construed as indicating that any described embodiment or design manner is preferred or has more advantages over another embodiment or design manner. Strictly speaking, the use of words such as "example," "in one example," "for example," etc. is intended to present related concepts in a concrete manner.

[0138] In order to facilitate understanding of the method provided in the embodiments of the present application, the following describes the system architecture of the method provided in the embodiments of the present application. It should be understood that the system architecture described in the embodiments of the present application is intended to more clearly describe the technical solutions in the embodiments of the present application, and does not constitute limitations on the technical solutions provided in the embodiments of the present application.

[0139] An embodiment of the present application provides a beacon frame transmission method in EMLSR mode. By considering the impact of spatial stream switching delay on beacon frame reception, a transmission opportunity (TXOP) holder is restricted to pre-terminate the TXOP for a certain period of time, ensuring that a non-AP MLD in EMLSR mode can complete spatial stream switching between links before the next target beacon transmission time (TBTT). This can prevent a non-AP MLD in EMLSR mode from missing an important beacon frame.

[0140] The beacon frame transmission method in EMLSR mode may be applied to a wireless communication system, for example, a wireless local area network system. The method may be implemented by a communication device in the wireless communication system, or a chip or processor in the communication device. The communication device may be a wireless communication device that supports parallel transmission on multiple links. For example, the communication device may be referred to as a multi-link device (MLD) or a multi-band device. Compared with a communication device that supports only single-link transmission, a multi-link device has higher transmission efficiency and higher throughput.

[0141] A multilink device includes one or more affiliated stations (STAs). An affiliated station is a logical station that can operate on one link, one frequency band, or one channel. An affiliated station may be an access point (AP) or a non-access point station (non-AP STA). In 802.11be, a multilink device whose affiliated station is an AP is called an AP multilink device (AP MLD), and a multilink device whose affiliated station is a non-AP STA is called a non-AP multilink device (non-AP MLD).

[0142] Optionally, one multilink device may include multiple logical stations. Each logical station operates on one link, but multiple logical stations can operate on the same link. During data transmission between the AP MLD and the non-AP MLD, a link identifier may be used to identify a link or a station on a link. Prior to communication, the AP MLD and the non-AP MLD may first negotiate or communicate with each other about the correspondence between the link identifier and the link or a station on the link. Therefore, during data transmission, the link identifier is conveyed without transmitting a large amount of signaling information to indicate the link or a station on the link. This reduces signaling overhead and improves transmission efficiency.

[0143] In one example, a management frame, such as a beacon frame or an association request frame, transmitted when AP MLD establishes a basic service set (BSS) carries an element, and the element includes multiple link identifier information fields. The link identifier information field may indicate a correspondence between a link identifier and a station operating on the link corresponding to the link identifier. The link identifier information field includes a link identifier and one or more of the following information: a medium access control (MAC) address, an operating class, and a channel number. One or more of the MAC address, the operating class, and the channel number may identify a link. In the case of an AP, the MAC address of the AP is the AP's basic service set identifier (BSSID). In another example, during the association process between multilink devices, AP MLD and non-AP MLD negotiate multiple link identifier information fields. A multilink association refers to an association between an AP of AP MLD and a STA of non-AP MLD. The association may facilitate separate associations between multiple STAs in the non-AP MLD and multiple APs in the AP MLD, with one STA associated with one AP. One or more STAs in the non-AP MLD may establish association relationships with one or more APs in the AP MLD and then communicate with the one or more APs.

[0144] Optionally, the multilink device may perform wireless communication in accordance with the IEEE 802.11 series protocol. For example, a station conforming to the ultra-high throughput standard or a station conforming to or compatible with IEEE 802.11be may perform communication with another device. Of course, the other device may or may not be a multilink device.

[0145] The beacon frame transmission method in EMLSR mode provided in the embodiments of the present application may be applied to a scenario in which one node communicates with one or more nodes, a single-user uplink / downlink communication scenario or a multi-user uplink / downlink communication scenario, or a device-to-device (D2D) communication scenario. In the embodiments of the present application, the term "communication" may also be described as "data transmission," "information transmission," or "transmission." The term "transmission" may generally refer to sending and receiving.

[0146] Any one of the aforementioned nodes may be an AP MLD or a non-AP MLD. For example, the beacon frame transmission method in the EMLSR mode is applied to a scenario in which an AP MLD communicates with a non-AP MLD, a scenario in which a non-AP MLD communicates with a non-AP MLD, or a scenario in which an AP MLD communicates with an AP MLD. This is not limited to the embodiments of the present application. Optionally, one of the aforementioned nodes may be a multi-link device, and the other nodes may or may not be multi-link devices. A single-link device may be a STA.

[0147] For ease of explanation, a scenario in which an AP MLD communicates with a STA is used below to describe the system architecture of the present application. It should be understood that the STA in this specification has a broad meaning and can be a single-link STA or a non-AP MLD.

[0148] Please refer to FIG. 1. FIG. 1 is a schematic diagram depicting the architecture of a wireless communication system according to one embodiment of the present application. As shown in FIG. 1, the wireless communication system includes at least one AP MLD (e.g., AP MLD 100 in FIG. 1) and at least one non-AP MLD (e.g., non-AP MLD 200 and non-AP MLD 300 in FIG. 1). Optionally, FIG. 1 further includes a legacy station that supports transmission on only a single link (e.g., single-link non-AP STA 400 in FIG. 1, also referred to as STA 400). The AP MLD is a multi-link device that serves the non-AP MLD, and the non-AP MLD may communicate with the AP MLD over multiple links to achieve improved throughput. An AP in the AP MLD may communicate with a STA in the non-AP MLD over one link. It will be understood that the numbers of AP MLDs and non-AP MLDs in FIG. 1 are merely examples.

[0149] Optionally, please refer to Figure 2a. Figure 2a is a schematic diagram depicting the structure of a multi-link device according to one embodiment of the present application. The 802.11 standard focuses on the 802.11 physical layer (PHY) and medium access control (MAC) layer parts of a multi-link device. As shown in Figure 2a, multiple STAs included in the multi-link device are independent of each other at the low MAC layer and the PHY layer, and are also independent of each other at the high MAC layer. Please refer to Figure 2b. Figure 2b is a schematic diagram depicting another structure of a multi-link device according to one embodiment of the present application. As shown in Figure 2b, multiple STAs included in the multi-link device are independent of each other at the low MAC layer and the PHY layer, and share the high MAC layer. Of course, in the multi-link communication process, the non-AP MLD may use a structure having an independent high MAC layer, and the AP MLD may use a structure having a shared high MAC layer, or the non-AP MLD may use a structure having a shared high MAC layer, and the AP MLD may use a structure having an independent high MAC layer, or both the non-AP MLD and the AP MLD may use a structure having an independent high MAC layer. The schematic diagram of the internal structure of the multi-link device is not limited in the embodiments of the present application. Figures 2a and 2b are merely examples for explanation. For example, the high MAC layer or the low MAC layer may be implemented by a processor within the chip system of the multi-link device, or by different processing modules within the chip system.

[0150] For example, the multi-link device in this embodiment of the present application may be a single-antenna device or a multi-antenna device. For example, the multi-link device may be a device with three or more antennas. The number of antennas included in the multi-link device is not limited in this embodiment of the present application.

[0151] Optionally, please refer to FIG. 3. FIG. 3 is a schematic diagram of multi-link communication according to an embodiment of the present application. As shown in FIG. 3, the AP MLD includes n stations, which are AP1, AP2, ..., and APn. The non-AP MLD also includes n stations, which are STA1, STA2, ..., and STAn. The AP MLD and the non-AP MLD may perform parallel communication on Link 1, Link 2, ..., and Link n. An AP in the AP MLD may establish an association relationship with a STA in the non-AP MLD. For example, STA1 in the non-AP MLD establishes an association relationship with AP1 in the AP MLD. STA2 in the non-AP MLD establishes an association relationship with AP2 in the AP MLD. STAn in the non-AP MLD establishes an association relationship with APn in the AP MLD.

[0152] For example, a multilink device (which may be referred to herein as a non-AP MLD or an AP MLD) is a device having wireless communication capabilities. The device may be an entire system device, or a chip, processing system, or the like installed in the entire system device. A device having a chip or processing system installed therein may implement the methods and functions in the embodiments of the present application under the control of the chip or processing system. For example, in the embodiments of the present application, a non-AP MLD may have wireless transceiver capabilities, support 802.11 series protocols, and communicate with an AP MLD or another non-AP MLD. For example, a non-AP MLD is any user communication device that allows a user to communicate with an AP and a WLAN. For example, a non-AP MLD may be user equipment that can connect to a network, such as a tablet computer, desktop computer, laptop computer, notebook computer, ultra-mobile personal computer (UMPC), handheld computer, netbook, personal digital assistant (PDA), mobile phone, Internet of Things node in the Internet of Things, or in-vehicle communication device in the Internet of Vehicles. Alternatively, the non-AP MLD may be a chip and processing system within the aforementioned terminal. The AP MLD in this embodiment of the present application is a device that provides services to the non-AP MLD and may support the 802.11 series protocol. For example, the AP MLD may be a communication entity such as a communication server, a router, a switch, or a bridge, and the AP MLD may include various types of macro base stations, micro base stations, relay stations, etc. Of course, the AP MLD may alternatively be a chip and processing system within various types of devices. In this way, the methods and functions in the embodiments of the present application are implemented.

[0153] It should be understood that multi-link devices can support high-speed, low-latency transmission. With the continuous development of application scenarios for wireless local area networks, multi-link devices can be further applied to more scenarios, such as sensor nodes in smart cities (smart meters, smart electricity meters, smart air detection nodes, etc.), smart home smart devices (smart cameras, projectors, displays, televisions, stereos, refrigerators, washing machines, etc.), Internet of Things nodes, entertainment terminals (AR, VR, or other wearable devices, etc.), smart office smart devices (printers, projectors, etc.), Internet of Vehicles devices, and some infrastructure in daily life scenarios (vehicles, vending machines, supermarket self-service navigation terminals, self-service cash register devices, self-service ordering machines). The specific forms of AP MLD and Non-AP MLD are not limited in the embodiments of the present application and are merely examples for explanation purposes herein. The 802.11 protocol may support 802.11be or be a protocol compatible with 802.11be.

[0154] The above content briefly describes the system structure in the embodiment of the present application. In order to better understand the technical solution of the present application, the following briefly describes the content related to the present application.

[0155] 1. Beacon frame and target beacon transmission time (TBTT) A beacon frame is a management frame periodically transmitted in a WLAN. Typically, a beacon frame is transmitted by an access point device (including single-link AP and AP MLD) to broadcast basic information about the access point device. A beacon frame typically contains some important information, such as critical updates, including BSS parameter updates, TBTT information updates, etc. Therefore, it is recommended that station devices (including single-link STA and non-AP MLD) not miss beacon frames. This is because if a station device misses a beacon frame, which carries a BSS parameter update or TBTT information update, the station device may not be able to operate normally.

[0156] The TBTT indicates a predetermined time for beacon transmission. In multi-link communication, the AP MLD can broadcast the TBTT on each link. During the TBTT on a link, the AP MLD actively transmits beacon frames on the link, and the non-AP MLD actively receives beacon frames on the link. The non-AP MLD can then use the beacon frames for operations such as time synchronization and viewing the traffic indication message (TIM) field. In other words, beacon frames are transmitted periodically according to the TBTT, and each link has its own TBTT, which may be different on different links.

[0157] 2. Spatial Streams and Antennas A radio transmits multiple signals simultaneously, and each signal is called a spatial stream. In a multiple input multiple output (MIMO) system, the number of spatial streams is usually equal to or less than the number of antennas. If the number of antennas at the transmitting end is different from the number of antennas at the receiving end, the number of spatial streams is equal to or less than the minimum number of antennas at the transmitting end or receiving end. For example, a 4x4 (four transmitting antennas and four receiving antennas, also called 4 input and 4 output) MIMO system may be used to transmit four or fewer spatial streams, and a 3x2 (three transmitting antennas and two receiving antennas) MIMO system may transmit two or fewer spatial streams.

[0158] Optionally, the relationship between antennas and spatial streams in a MIMO system may be further used in this application.

[0159] 3. Communication process between non-AP MLD and AP MLD in EMLSR mode Please refer to Figure 4. Figure 4 is a schematic diagram of communication between non-AP MLD and AP MLD in EMLSR mode. Non-AP MLD in EMLSR mode receives on each link by using one antenna, i.e., non-AP MLD in EMLSR mode performs channel listening operation (i.e., CCA) on each link by using one antenna. In addition, non-AP MLD in EMLSR mode can receive initial control frames transmitted by AP MLD of OFDM PPDU type and non-HT duplicate PPDU type on each link by using one antenna, and reception of other types of frames is not supported. It should be understood that if the transmitting end uses one antenna to transmit on the link and the receiving end also uses one antenna to receive on the link, a 1x1 (one input, one output) antenna configuration is provided for the link. If the transmitting end uses two antennas to transmit on the link and the receiving end also uses two antennas to receive on the link, a 2x2 (two inputs, two outputs) antenna configuration is provided for the link. As shown in FIG. 4, the AP transmits an initial control frame, such as a request to send (RTS) frame, on channel 2 (ch2) by using one antenna. The initial control frame includes a channel switch signal, which instructs the STA to switch the antenna for reception. The STA receives the initial control frame transmitted by the AP on channel 2 by using one antenna (in this case, a 1×1 antenna configuration is provided for channel 2), replies with a clear to send (CTS) frame on channel 2, and temporarily switches the receiving antenna (radio) on channel 1 (ch1) to channel 2 based on the instruction of the channel switch signal in the initial control frame, and performs downlink data transmission on channel 2.

[0160] Some management frames (e.g., beacon frames and association request frames in the EHT standard) are long and complex, and the PPDU type of the management frame is usually the PPDU type of a higher standard, such as the HT type, the very high throughput (VHT) type, the high efficiency (HE) type, or the EHT type. Therefore, how a non-AP MLD in EMLSR mode receives management frames (e.g., beacon frames and association request frames) in listening operation becomes an urgent problem to be solved.

[0161] Regarding the question of how a non-AP MLD in EMLSR mode receives management frames (such as beacon frames and association request frames) during listening operation, in one embodiment, due to the periodicity of beacon frames, the non-AP MLD may prepare prior to the TBTT and then receive beacon frames when an RTS frame is not required. That is, the AP MLD does not transmit an initial control frame, and other individually addressed management frames may be transmitted as data frames. In another embodiment, management frames and broadcast frames are added to the frame types that can be successfully received by a non-AP MLD in EMLSR mode using one antenna. It should be understood that the EMLSR mode exists only when the receiving capability of the STA is limited. Therefore, if the receiving capability of a non-AP MLD using one antenna is expanded to the extent that management frames can be freely received, it actually requires the improved receiving capability of a non-AP MLD using one antenna.

[0162] An embodiment of the present application provides a beacon frame transmission method in EMLSR mode. A TXOP holder is restricted to end a TXOP in a period prior to the nearest TBTT to ensure that a non-AP MLD in EMLSR mode can complete spatial stream switching between links before the next TBTT. This can prevent a non-AP MLD in EMLSR mode from missing an important beacon frame.

[0163] The following will describe in detail the technical solutions provided in this application with reference to more accompanying drawings.

[0164] The technical solutions provided in this application are described in detail using four embodiments. Embodiment 1 describes how beacon frames are transmitted between an AP MLD and a non-AP MLD in EMLSR mode when the AP MLD functions as a TXOP holder. Embodiment 2 describes how beacon frames are transmitted between an AP MLD and a non-AP MLD when the non-AP MLD functions as a TXOP holder. Embodiment 3 describes a link capability indication method in EMLSR mode. Embodiment 4 describes how a non-AP MLD in EMLSR mode transmits uplink non-trigger-based data, i.e., how to transmit uplink data independently. It should be understood that the technical solutions described in Embodiments 1 to 4 of this application may be combined to form new embodiments, and parts having the same or similar concepts or solutions may be mutually referenced or combined. The following describes these embodiments individually in detail.

[0165] It should be understood that both AP MLD and non-AP MLD in the present application support the 802.11be protocol (also called Wi-Fi 7 or EHT protocol) and may further support another WLAN communication protocol, such as 802.11ax or 802.11ac. It should be understood that AP MLD and non-AP MLD in the present application may further support a next-generation protocol of 802.11be. In other words, the method provided in the present application is applicable not only to the 802.11be protocol but also to a next-generation protocol of 802.11be.

[0166] It should be further understood that the non-AP MLD in the present application is in (or operates in) EMLSR mode. Specifically, the non-AP MLD in the present application performs listening operation (i.e., CCA) and receives initial control frames of OFDM PPDU type and non-HT duplicate PPDU type on each link by using one antenna. For ease of explanation, in this specification, the non-AP MLD in (or operating in) EMLSR mode will be simply referred to as EMLSR non-AP MLD.

[0167] Embodiment 1 Embodiment 1 of the present application mainly describes how to transmit beacon frames between an AP MLD and a non-AP MLD in EMLSR mode when the AP MLD acts as a TXOP holder, to prevent the non-AP MLD in EMLSR mode from missing important beacon frames.

[0168] Beacon frames contain some important information, such as critical updates, which include TBTT information updates. If a non-AP MLD misses a beacon frame and receives it based on the original (or old) TBTT, the new beacon frame will be missed. In addition, for delivery traffic indication message (DTIM) beacon frames, if a non-AP MLD misses a DTIM beacon frame, the non-AP MLD may miss an opportunity to transmit a downlink data packet. Therefore, it is recommended that beacon frames not be missed for non-AP MLD.

[0169] Please refer to Figure 5. Figure 5 is a schematic flowchart of a beacon frame transmission method in EMLSR mode according to an embodiment of the present application. As shown in Figure 5, the beacon frame transmission method in EMLSR mode includes, but is not limited to, the following steps:

[0170] S101: The TXOP holder (AP MLD) transmits a first frame before a first delay prior to the next target beacon transmission time TBTT, the first frame indicating the end of the transmission opportunity TXOP on the first link, the AP MLD to transmit a beacon frame on the second link at the next TBTT, and the first delay is used by the EMLSR non-AP MLD to change the spatial stream on the second link to support beacon frame reception.

[0171] S102: The non-AP MLD receives the first frame before the first delay prior to the next TBTT.

[0172] S103: The non-AP MLD changes the spatial stream on the second link to support beacon frame reception within a first delay after the end of the TXOP on the first link.

[0173] S104: The AP MLD transmits a beacon frame on the second link at the next TBTT.

[0174] S105: The non-AP MLD receives a beacon frame by using the spatial stream supported on the second link in the next TBTT.

[0175] Optionally, since beacon frames are transmitted periodically, if the AP MLD and EMLSR non-AP MLD are in a TXOP prior to the next TBTT and the link associated with the TXOP is not the same as the link on which the AP MLD transmits the beacon frame in the next TBTT, the spatial stream needs to be switched after the TXOP ends to receive the beacon frame in the next TBTT, in order to ensure that the non-AP MLD can successfully receive the beacon frame in the next TBTT.

[0176] Optionally, a first link and a second link exist between a TXOP holder AP MLD and an EMLSR non-AP MLD. The AP MLD obtains a transmission opportunity (TXOP) on the first link through channel contention and transmits data with the EMLSR non-AP MLD on the first link within the TXOP. Therefore, the AP MLD is the TXOP holder. If the AP MLD determines that the AP MLD is to transmit a beacon frame on the second link at the next target beacon transmission time (TBTT), and the second link is not the same as the link associated with the current TXOP (i.e., the aforementioned first link), the AP MLD transmits the first frame before a first delay prior to the next TBTT. In this specification, the AP on the link associated with the TXOP (i.e., the first link) needs to know the timing synchronization function (TSF) on another link to determine the link associated with the next TBTT. The first frame indicates TXOP termination on the first link. The first frame can be a control frame, such as a contention-free end (CF-end) frame or a CTS-to-self frame. In response, the non-AP MLD receives the first frame before a first delay prior to the next TBTT. The non-AP MLD changes the spatial stream on the second link to support beacon frame reception within the first delay after the TXOP termination on the first link. In other words, the non-AP MLD must complete the change of the spatial stream on the second link within the period from the TXOP termination on the first link to the next TBTT. Alternatively, the time required for the non-AP MLD to change the spatial stream on the second link to support beacon frame reception must be less than or equal to the first delay. The AP MLD transmits a beacon frame on the second link at the next TBTT.In response, the non-AP MLD receives the beacon frame by using the spatial streams currently supported on the second link at the next TBTT. It should be understood that prior to the next TBTT, the non-AP MLD switches all or some of the spatial streams supported on the second link to the second link. Therefore, at the next TBTT, the non-AP MLD can successfully receive the beacon frame. The first delay is used by the EMLSR non-AP MLD to change the spatial streams on the second link to support beacon frame reception.

[0177] Optionally, the first delay may be further described as being used by EMLSR non-AP MLD to switch a receive antenna on the second link to support beacon frame reception. It should be understood that "switching receive antennas" in this application refers to "switching the operating frequency band (or operating link) of a receive antenna" and is a logical switch. For example, "switching all or some of the receive antennas on a link to another link" means switching all or some of the receive antennas currently operating on the link to another link.

[0178] In this application, the "next TBTT" is the TBTT that follows the TXOP in time and is closest to the TXOP.

[0179] It should be understood that the first link and the second link in this embodiment of the present application are two different links between the AP MLD and the EMLSR non-AP MLD. In practical application, there may be more links (three or more links) between the non-AP MLD and the AP MLD. The first link represents the link related to the current TXOP among the multiple links between the non-AP MLD and the AP MLD, and the second link represents the link where the next TBTT arrives among the multiple links between the non-AP MLD and the AP MLD.

[0180] Optionally, when non-AP MLD receives on both the first link and the second link by using a single spatial stream (or a single antenna), the receiving capability on one link is limited (i.e., only PPDUs of certain types (i.e., OFDM type and non-HT duplicate type) can be received), and the receiving capability on the other link is not limited (i.e., all types of PPDUs can be received). Alternatively, when non-AP MLD receives on both the first link and the second link by using a single spatial stream (or a single antenna), the receiving capability on both links is limited (i.e., only PPDUs of certain types can be received). Before transmitting the first frame, AP MLD determines the first delay based on the receiving capability on each link when non-AP MLD receives by using a single spatial stream (or a single antenna). For example, non-AP MLD actively reports the receiving capability on each link when non-AP MLD receives by using a single spatial stream (or a single antenna). For specific implementations, please refer to the description of embodiment 3 below, and details will not be described in this specification.

[0181] Optionally, before receiving a beacon, the EMLSR non-AP MLD needs to switch a spatial stream on another link to the link for receiving the beacon frame. Therefore, there is a certain switching delay. In this application, one or more EMLSR switching delays may be defined in terms of spatial streams. The details are as follows: (1) EMLSR delay 1 is the time required to switch from a single spatial stream on one link to multiple spatial streams on another link; (2) EMLSR delay 2 is the time required to switch from multiple spatial streams on one link to a single spatial stream on another link; and (3) EMLSR delay 3 is the time required to switch from multiple spatial streams on one link to multiple spatial streams on another link. In this application, one or more EMLSR switching delays may alternatively be defined in terms of antennas. The details are as follows: (1) EMLSR delay 1 is the time required to switch from a single antenna configuration on one link to another link to form a multi-antenna configuration. (2) EMLSR Delay 2 is the time it takes to switch part of a multi-antenna configuration on one link to another link to form a single-antenna configuration. (3) EMLSR Delay 3 is the time it takes to switch part of a multi-antenna configuration on one link to another link to form a multi-antenna configuration.

[0182] It should be understood that the EMLSR switching delay in this application is for non-AP MLD. In other words, non-AP MLD must complete the switching / changing of spatial streams / receiving antennas between links within the defined EMLSR switching delay. EMLSR delay 1 and EMLSR delay 2 may be the same or different. In other words, if EMLSR delay 1 is the same as EMLSR delay 2, only one EMLSR switching delay may be defined in this application. Alternatively, EMLSR delay 3 may not be defined in this application and may be determined based on EMLSR delay 1 and EMLSR delay 2. For example, EMLSR delay 3 is the maximum value of EMLSR delay 1 and EMLSR delay 2, or the sum of EMLSR delay 1 and EMLSR delay 2.

[0183] It should be further understood that the "spatial stream switching" referred to in this application essentially occurs due to receive antenna switching between links. For example, before the AP MLD acquires the TXOP, the non-AP MLD has only a single antenna configuration on the link. After the TXOP ends, the non-AP MLD configures dual antennas for the link, i.e., the dual antennas operate in the same operating frequency band (i.e., the link). The number of spatial streams increases, i.e., the number of spatial streams is also switched from single stream to dual stream.

[0184] Optionally, the first delay may be one of EMLSR Delay 1, EMLSR Delay 2, and EMLSR Delay 3. The following describes a specific implementation of the first delay when the reception capabilities between links are asymmetric and all reception capabilities are limited when non-AP MLD performs reception by using a single spatial stream (or a single antenna).

[0185] 1. Asymmetric receive capabilities between links Optionally, the asymmetry in reception capabilities between links when non-AP MLD receives by using a single spatial stream (or a single antenna) can be explained from two perspectives.

[0186] From the perspective of spatial streams, EMLSR non-AP MLD includes two types of spatial streams: a first type spatial stream and a second type spatial stream. When non-AP MLD receives on a link by using the first type spatial stream, the reception capability is limited. In this case, it can be expressed as only some types of PPDUs (e.g., non-HT overlap types) being able to be received on the link. When non-AP MLD receives on the same link by using the second type spatial stream, the reception capability is not limited. In this case, it can be expressed as all types of PPDUs being able to be received on the link.

[0187] From an antenna perspective, the antenna capabilities of EMLSR non-AP MLD are configured so that one antenna is deployed for each of the two links. One antenna has strong reception capabilities, which can be expressed as the antenna being able to receive all types of PPDUs. In this case, the single spatial stream generated by the antenna also has strong reception capabilities. The other antenna has weak reception capabilities, i.e., only some types of PPDUs (e.g., non-HT duplicate types) can be received. In this case, the single spatial stream generated by the antenna also has weak reception capabilities. For ease of explanation, in this specification, an antenna with strong reception capabilities is referred to as a regular antenna (regular radio), and an antenna with weak reception capabilities is referred to as a reduced antenna (reduced radio). It should be understood that the aforementioned first type of spatial stream can be understood as a single spatial stream generated by a reduced antenna, and the aforementioned second type of spatial stream can be understood as a single spatial stream generated by a regular antenna.

[0188] Embodiment 1.1: When non-AP MLD receives on each link by using a single spatial stream, the spatial stream configuration is as follows: non-AP MLD receives on the first link by using a first spatial stream (or a limited antenna) and receives on the second link by using a second spatial stream (or a normal antenna). The first spatial stream is a spatial stream of a first type of spatial stream, and the second spatial stream is a single spatial stream of a second type of single spatial stream. In other words, when non-AP MLD receives on the first link by using the first spatial stream (or a limited antenna), the receiving capability is limited, that is, only some types of PPDUs can be received. When non-AP MLD receives on the second link by using the second spatial stream (or a normal antenna), the receiving capability is not limited, that is, all types of PPDUs can be received. During the process of data transmission on the first link by the AP MLD and the non-AP MLD (which refers to the period from the transmission of a data frame by the AP MLD to the non-AP MLD on the first link to the end of the TXOP), the spatial streams supported on the first link are multiple spatial streams including the first spatial stream and the second spatial stream. In other words, within the TXOP, the spatial streams supported on the first link by the non-AP MLD are multiple spatial streams including the first spatial stream and the second spatial stream. That is, within the TXOP, to ensure data transmission on the first link, the second spatial stream (or the normal antenna) originally configured for (or operating on) the second link is temporarily switched to the first link for data transmission. Therefore, within the TXOP, no spatial streams are supported on the second link of the non-AP MLD, i.e., the receive antenna of the non-AP MLD is not operating on the second link.

[0189] The first link (the link associated with the current TXOP) and the second link (the link on which the next TBTT arrives) are not the same link. To successfully receive the beacon frame, after the TXOP ends, the non-AP MLD may change / switch the spatial stream on the second link to support beacon frame reception. For example, the second spatial stream (i.e., the normal antenna) among the multiple spatial streams (or multiple antennas) supported on the first link is switched to the second link to obtain a single spatial stream (or single antenna). Therefore, to ensure that the non-AP MLD has enough time to complete the spatial stream (or receive antenna) switching / change between links, the first delay is the period required for the non-AP MLD to change from not supporting a spatial stream on the second link to supporting a single spatial stream, i.e., the first delay is the EMLSR delay2 defined above. Therefore, the spatial stream supported by non-AP MLD on the second link is a single spatial stream for the next TBTT, and the reception capability is not limited when non-AP MLD receives on the second link by using a single spatial stream. In other words, the receive antenna of non-AP MLD on the second link is a normal antenna for the next TBTT.

[0190] Please refer to FIG. 6. FIG. 6 is a sequence diagram 1 of beacon frame transmission when the receiving capabilities between links are asymmetric according to one embodiment of the present application. As shown in FIG. 6, the current TXOP is on link1 (i.e., the first link mentioned above), and the next TBTT is to arrive on link2 (i.e., the second link mentioned above). Within the TXOP, the spatial stream (or receiving antenna) supported by non-AP MLD on link1 is a dual spatial stream (or dual antenna), including a single spatial stream (or limited antenna) with limited receiving capabilities and a single spatial stream (or normal antenna) with unrestricted receiving capabilities. Therefore, in order to successfully receive the beacon frame, after the TXOP ends, the non-AP MLD can switch back to the original antenna configuration, i.e., the non-AP MLD switches the single spatial stream with unrestricted receiving capabilities / normal antenna on link1 back to link2, ensuring that the non-AP MLD can successfully receive the beacon frame on link2. In this case, the TXOP holder (e.g., AP MLD) needs to end the TXOP within EMLSR delay 2 (i.e., the first delay) prior to the next TBTT to ensure that the non-AP MLD has enough time to switch from a single spatial stream / normal antenna with unlimited receiving capability on link 1 back to link 2 and successfully receive the beacon frame at the next TBTT. delay 2 in Figure 6 represents EMLSR delay 2.

[0191] Embodiment 1.2: When non-AP MLD receives on each link by using a single spatial stream, the spatial stream configuration is as follows: non-AP MLD receives on the first link by using the second spatial stream (or a normal antenna) and receives on the second link by using the first spatial stream (or a limited antenna). The first spatial stream is a single spatial stream of a first type, and the second spatial stream is a single spatial stream of a second type. In other words, when non-AP MLD receives on the first link by using the second spatial stream (or a normal antenna), the reception capability is not limited, that is, all types of PPDUs can be received. When non-AP MLD receives on the second link by using the first spatial stream (or a limited antenna), the reception capability is limited, that is, only some types of PPDUs can be received. In the process of data transmission on the first link by the AP MLD and the non-AP MLD (which refers to the period from the transmission of a data frame by the AP MLD to the non-AP MLD on the first link to the end of the TXOP), the spatial streams supported on the first link are multiple spatial streams including the first spatial stream and the second spatial stream. In other words, within the TXOP, the spatial streams supported on the first link by the non-AP MLD are multiple spatial streams including the first spatial stream and the second spatial stream. That is, within the TXOP, to ensure multi-stream data transmission on the first link, the first spatial stream (or the limited antenna) originally configured for (or operating on) the second link is temporarily switched to the first link for data transmission. Therefore, within the TXOP, no spatial streams are supported on the second link of the non-AP MLD, i.e., the receive antenna of the non-AP MLD is not operating on the second link.

[0192] The aforementioned first link (the link associated with the current TXOP) and the aforementioned second link (the link on which the next TBTT arrives) are not the same link. To successfully receive the beacon frame, non-AP MLD needs to change / switch the spatial stream on the second link to support beacon frame reception.

[0193] In one embodiment, after the TXOP ends, the non-AP MLD may switch a second spatial stream (i.e., a normal antenna) among the multiple spatial streams (or multiple antennas) supported on the first link to the second link to obtain a single spatial stream (or single antenna), while the first spatial stream (i.e., a limited antenna) is maintained on the first link. Therefore, to ensure that the non-AP MLD has enough time to complete the spatial stream (or receive antenna) switch / change between links, the first delay is the period required for the non-AP MLD to change from supporting no spatial streams on the second link to supporting a single spatial stream, i.e., the first delay is the EMLSR delay2 defined above. Therefore, the spatial stream supported by the non-AP MLD on the second link is a single spatial stream for the next TBTT, and the receiving capability is not limited when the non-AP MLD receives on the second link by using a single spatial stream. In other words, the non-AP MLD receiving antenna on the second link is the normal antenna for the next TBTT.

[0194] Please refer to Figure 7a. Figure 7a is a sequence diagram 2 of beacon frame transmission when the receiving capabilities between links are asymmetric according to one embodiment of the present application. As shown in Figure 7a, the current TXOP is on link2 (i.e., the first link), and the next TBTT is to arrive on link1 (i.e., the second link). Within the TXOP, the spatial stream (or receiving antenna) supported by non-AP MLD on link2 (i.e., the first link) is a dual spatial stream (or dual antenna), including a single spatial stream (or restricted antenna) with restricted receiving capabilities and a single spatial stream (or normal antenna) with unrestricted receiving capabilities. Therefore, to successfully receive the beacon frame, after the TXOP ends, the non-AP MLD may choose to switch the single spatial stream / normal antenna with unrestricted receiving capabilities on link2 (i.e., the first link) to link1 (i.e., the second link), ensuring that the non-AP MLD can successfully receive the beacon frame on link1 (i.e., the second link). A single spatial stream / limited antenna with limited receiving capability is maintained on link2 (i.e., the first link). In this case, the TXOP holder (e.g., AP MLD) needs to end the TXOP within EMLSR delay2 (i.e., the first delay) prior to the next TBTT to ensure that the non-AP MLD has enough time to switch the single spatial stream / normal antenna with unlimited receiving capability on link2 to link1 and successfully receive the beacon frame at the next TBTT. delay2 in Figure 7a represents EMLSR delay2.

[0195] In another embodiment, after the TXOP ends, the non-AP MLD may switch all spatial streams (or antennas) supported on the first link to the second link to acquire multiple spatial streams (or antennas). Therefore, to ensure that the non-AP MLD has enough time to complete the spatial stream (or receive antenna) switching / change between links, the first delay is the period required for the non-AP MLD to change from supporting no spatial streams on the second link to supporting multiple spatial streams (or antennas), i.e., the first delay is the EMLSR delay 3 defined above. Therefore, the spatial streams supported on the second link by the non-AP MLD are multiple spatial streams including the first spatial stream and the second spatial stream at the next TBTT. In other words, the receive antennas of the non-AP MLD on the second link are multiple antennas including a normal antenna and a limited antenna at the next TBTT.

[0196] Please refer to Figure 7b. Figure 7b is a sequence diagram 3 of beacon frame transmission when the receiving capabilities between links are asymmetric according to an embodiment of the present application. As shown in Figure 7b, the current TXOP is on link2 (i.e., the first link mentioned above), and the next TBTT is to arrive on link1 (i.e., the second link mentioned above). Within the TXOP, the spatial stream (or receiving antenna) supported by non-AP MLD on link2 (i.e., the first link mentioned above) is a dual spatial stream (or dual antenna), including a single spatial stream (or limited antenna) with limited receiving capabilities and a single spatial stream (or normal antenna) with unrestricted receiving capabilities. Therefore, to successfully receive the beacon frame, after the TXOP ends, the non-AP MLD may choose to directly switch the dual spatial stream (or dual antenna) on link2 to link1, ensuring that the non-AP MLD can successfully receive the beacon frame on link1. In this case, the TXOP holder (e.g., AP MLD) needs to end the TXOP within EMLSR Delay 3 (i.e., the first delay) prior to the next TBTT to ensure that the non-AP MLD has enough time to switch the dual spatial stream (or dual antenna) on link 2 to link 1 and successfully receive the beacon frame at the next TBTT. Delay 3 in Figure 7b represents EMLSR Delay 3.

[0197] Embodiment 1.3: When non-AP MLD receives on each link by using a single spatial stream, the spatial stream configuration is as follows: non-AP MLD receives on the first link by using the second spatial stream (or a normal antenna) and receives on the second link by using the first spatial stream (or a limited antenna). The first spatial stream is a single spatial stream of a first type, and the second spatial stream is a single spatial stream of a second type. In other words, when non-AP MLD receives on the first link by using the second spatial stream (or a normal antenna), the reception capability is not limited, that is, all types of PPDUs can be received. When non-AP MLD receives on the second link by using the first spatial stream (or a limited antenna), the reception capability is limited, that is, only some types of PPDUs can be received. In the process of AP MLD and non-AP MLD transmitting data on the first link (this refers to the period from the AP MLD transmitting a data frame to the non-AP MLD on the first link to the end of the TXOP), the spatial stream supported on the first link is the second spatial stream. In other words, within the TXOP, the spatial stream supported on the first link by the non-AP MLD is a single spatial stream. Therefore, within the TXOP, the spatial stream supported on the second link by the non-AP MLD is a single spatial stream, while when the non-AP MLD receives on the second link by using a single spatial stream, the receiving capability is limited. In other words, the limited antenna of the non-AP MLD operates on the second link within the TXOP.

[0198] The first link (the link associated with the current TXOP) and the second link (the link on which the next TBTT arrives) are not the same link. To successfully receive the beacon frame, the non-AP MLD may change / switch the spatial stream on the second link to support beacon frame reception. For example, the second spatial stream (or normal antenna) supported on the first link is switched to the second link to form multiple spatial streams (or multiple antennas) with the original first spatial stream (or limited antenna) on the second link. Therefore, to ensure that the non-AP MLD has enough time to complete the spatial stream (or receive antenna) switching / change between links, the first delay is the period required for the non-AP MLD to change the spatial stream supported on the second link from a single spatial stream to multiple spatial streams, i.e., the first delay is the EMLSR delay 1 defined above. Therefore, the spatial streams supported by non-AP MLD on the second link are multiple spatial streams including the first spatial stream and the second spatial stream at the next TBTT. In other words, the receive antenna of non-AP MLD on the second link is a dual antenna including a normal antenna and a restricted antenna at the next TBTT.

[0199] Please refer to Figure 8. Figure 8 is a sequence diagram 4 of beacon frame transmission when the receiving capabilities between the links are asymmetric according to an embodiment of the present application. When the non-AP MLD receives on each link by using a single spatial stream, the spatial stream configuration is as follows: the non-AP MLD receives on the first link by using the second single spatial stream (or a normal antenna). Therefore, after obtaining a TXOP on the first link, the AP MLD does not need to transmit an initial control frame on the first link and can directly transmit a single-stream data frame. As shown in Figure 8, in the TXOP, the non-AP MLD receives a single-stream data frame on link2 (i.e., the first link) by using a single spatial stream (or a normal antenna) with unlimited receiving capabilities. The next TBTT is expected to arrive on link1 (i.e., the second link). To successfully receive the beacon frame, after the TXOP ends, the non-AP MLD may choose to switch the single spatial stream / normal antenna with unrestricted reception capability on link2 to link1, forming a dual spatial stream (or dual antenna) with the original single spatial stream / normal antenna with restricted reception capability on link1, ensuring that the non-AP MLD can successfully receive the beacon frame on link1. In this case, the TXOP holder (e.g., AP MLD) needs to end the TXOP within EMLSR delay 1 (i.e., the first delay) prior to the next TBTT, ensuring that the non-AP MLD has enough time to switch the single spatial stream / normal antenna with unrestricted reception capability on link2 to link1 and successfully receive the beacon frame at the next TBTT. delay 1 in FIG. 8 represents EMLSR delay 1.

[0200] 2. The receiving capabilities between the links are symmetrical Optionally, in this embodiment of the present application, the reception capability of the EMLSR non-AP MLD on each link is symmetric. Specifically, when the non-AP MLD receives on the link by using a single spatial stream (or a single antenna), the reception capability is limited, or when each single spatial stream (or each antenna) of the non-AP MLD is used individually, the reception capability of the non-AP MLD is weak, i.e., only some types of PPDUs can be received. In this case, the non-AP MLD cannot receive beacon frames by using a single spatial stream (or a single antenna).

[0201] Optionally, because receiving capability is limited when non-AP MLD receives on each link by using a single spatial stream, in the process in which AP MLD and non-AP MLD transmit data on the first link (which refers to the period from AP MLD transmitting a data frame to non-AP MLD on the first link to the end of the TXOP), the spatial stream (or receive antenna) supported on the first link is multiple spatial streams (or multiple antennas). In other words, to ensure data transmission on the first link within the TXOP, the single spatial stream (or limited antenna) originally configured for the second link (or operating on the second link) is temporarily switched to the first link for data transmission. Therefore, no spatial stream is supported on the second link of non-AP MLD within the TXOP, i.e., the receive antenna of non-AP MLD does not operate on the second link within the TXOP.

[0202] However, to successfully receive the beacon frame, after the TXOP ends, the non-AP MLD may change / switch the spatial streams on the second link to support beacon frame reception. For example, the multiple spatial streams (or multiple antennas) supported on the first link are switched to the second link to obtain multiple spatial streams (or multiple antennas). Therefore, to ensure that the non-AP MLD has enough time to complete the spatial stream (or receive antenna) switch / change between links, the first delay is the period required for the non-AP MLD to change from not supporting spatial streams on the second link to supporting multiple spatial streams, i.e., the first delay is the EMLSR delay 3 defined above. Therefore, the spatial streams (or receive antennas) supported on the second link by the non-AP MLD are multiple spatial streams (or multiple antennas) at the next TBTT.

[0203] Please refer to FIG. 9. FIG. 9 is a sequence diagram of beacon frame transmission when the receiving capabilities between links are symmetric according to one embodiment of the present application. As shown in FIG. 9, the current TXOP is on link1 (i.e., the first link mentioned above), and the next TBTT is to arrive on link2 (i.e., the second link mentioned above). In the TXOP, the spatial stream (or receiving antenna) supported by non-AP MLD on link1 (i.e., the first link mentioned above) is a dual spatial stream (or dual antenna) including two single spatial streams (or two limited antennas) with limited receiving capabilities. Therefore, to successfully receive the beacon frame, after the TXOP ends, the non-AP MLD may switch both dual spatial streams (or dual antennas) on link1 to link2 to ensure that the non-AP MLD can successfully receive the beacon frame on link2. In this case, the TXOP holder (e.g., AP MLD) needs to end the TXOP within EMLSR delay 3 (i.e., the first delay) prior to the next TBTT to ensure that the non-AP MLD has enough time to switch both dual spatial streams (or dual antennas) on link 1 to link 2 and successfully receive the beacon frame at the next TBTT. delay 3 in Figure 9 represents EMLSR delay 3.

[0204] In this embodiment of the present application, in two scenarios where the receiving capability between links is symmetric and asymmetric when non-AP MLD receives by using a single spatial stream (or a single antenna), the impact of EMLSR switching delay on beacon frame reception is considered separately, and it can be seen that the TXOP holder is restricted to end the TXOP before the EMLSR switching delay (i.e., the first delay) prior to the next TBTT to ensure that the non-AP MLD has enough time to complete the spatial stream switching / changing. This can prevent the non-AP MLD in EMLSR mode from missing important beacon frames.

[0205] In an optional embodiment, the link associated with the current TXOP and the link for transmitting a beacon frame at the next TBTT may be the same link. A first link exists between the EMLSR non-AP MLD and the TXOP holder AP MLD. Specifically, it is assumed that the link associated with the current TXOP and the link for transmitting a beacon frame at the next TBTT are the first link. That is, the AP MLD acquires a TXOP on the first link through channel contention, and the AP MLD is to transmit a beacon frame on the first link at the next TBTT. After acquiring the TXOP, the AP MLD transmits data with the EMLSR non-AP MLD on the first link within the TXOP. The AP MLD transmits a first frame on the first link prior to the next TBTT, and the first frame indicates TXOP termination on the first link. Correspondingly, the non-AP MLD receives a first frame on the first link prior to the next TBTT and either maintains the spatial streams supported on the first link or does not change the spatial streams supported on the first link. The AP MLD transmits a beacon frame on the first link at the next TBTT. Correspondingly, the non-AP MLD receives a beacon frame by using the spatial streams currently supported on the first link at the next TBTT. If the non-AP MLD receives on the first link by using a single spatial stream, and reception capability is not limited (i.e., all types of PPDUs can be received), the spatial streams supported on the first link may be a single spatial stream. Alternatively, the spatial streams supported on the first link may be multiple spatial streams. In other words, if the link related to the current TXOP and the link for transmitting a beacon frame at the next TBTT are the same link, the non-AP MLD may maintain the current spatial streams on the link. That is, the spatial streams supported on the link are not changed after the TXOP ends.

[0206] Optionally, the estimated time of TXOP termination must precede the next TBTT, and the time interval between the estimated time of TXOP termination and the next TBTT must be less than or equal to a threshold, for example 64 μs or 128 μs.

[0207] It can be seen that since the link related to the current TXOP and the link for transmitting a beacon frame in the next TBTT are the same link, the non-AP MLD can maintain the current spatial stream and successfully receive a beacon frame in the next TBTT, which can prevent the non-AP MLD in EMLSR mode from missing an important beacon frame.

[0208] In another optional embodiment, if the link related to the current TXOP and the link for transmitting a beacon frame in the next TBTT are the same link and the spatial stream (or receive antenna) on the link is a single spatial stream (or a single antenna), the single-stream data frame transmitted by the AP MLD can serve as the initial control frame. That is, after receiving the single-stream data frame, the non-AP MLD may alternatively change the spatial streams supported on the link from a single spatial stream (or a single antenna) to multiple spatial streams (or multiple antennas), and then perform reception by using the multiple spatial streams (or multiple antennas). Note that in this case, the single-stream data frame needs to be extended by padding. Specifically, the AP MLD obtains a TXOP on the first link through channel contention and transmits data with the EMLSR non-AP MLD on the first link within the TXOP. The AP MLD is to transmit a beacon frame on the first link in the next TBTT, and the spatial stream (or receive antenna) supported by the non-AP MLD on the first link is a single spatial stream (or a single antenna). The AP MLD transmits a single-stream data frame extended by padding prior to the next TBTT, and the single-stream data frame instructs the non-AP MLD to change the spatial stream (or receive antenna) on the first link. Correspondingly, after receiving the single-stream data frame, the non-AP MLD changes the spatial streams supported on the first link from a single spatial stream to multiple spatial streams (or multiple antennas). The AP MLD transmits a beacon frame on the first link at the next TBTT. Correspondingly, the non-AP MLD receives a beacon frame by using the spatial streams currently supported on the first link at the next TBTT.The transmission delay of the single-stream data frame extended by the padding should be equal to or greater than the period required for non-AP MLD to change the spatial streams supported on the first link from a single spatial stream (or a single antenna) to multiple spatial streams (or multiple antennas). In other words, non-AP MLD must complete the change / switching of the spatial streams (or receive antennas) supported on the first link within the transmission time of the single-stream data frame.

[0209] It can be seen that in this embodiment of the present application, if the link associated with the current TXOP and the link on which the next TBTT arrives are the same link, another viable way of receiving a beacon frame is provided.

[0210] Embodiment 2 Embodiment 2 of the present application mainly describes how to transmit beacon frames between an AP MLD and a non-AP MLD in EMLSR mode when the non-AP MLD functions as a TXOP holder, so as to prevent the non-AP MLD in EMLSR mode from missing important beacon frames.

[0211] Please refer to Fig. 10. Fig. 10 is another schematic flowchart of a beacon frame transmission method in EMLSR mode according to an embodiment of the present application. As shown in Fig. 10, the beacon frame transmission method in EMLSR mode includes, but is not limited to, the following steps:

[0212] S201: A TXOP holder (non-AP MLD) transmits a first frame before a first delay prior to the next TBTT, where the first frame indicates the end of the TXOP on the first link, and the first delay is used by the EMLSR non-AP MLD to change the spatial stream on the second link to support beacon frame reception.

[0213] S202: The AP MLD receives a first frame before a first delay prior to the next TBTT.

[0214] S203: The non-AP MLD changes the spatial stream on the second link to support beacon frame reception within a first delay after the end of the TXOP on the first link.

[0215] S204: The AP MLD transmits a beacon frame on the second link at the next TBTT.

[0216] S205: The non-AP MLD receives a beacon frame by using the spatial stream supported on the second link in the next TBTT.

[0217] Optionally, there are a first link and a second link between the TXOP holder non-AP MLD and the AP MLD. The EMLSR non-AP MLD acquires a TXOP on the first link through channel contention and transmits data with the AP MLD on the first link in the TXOP. For details on how the EMLSR non-AP MLD performs autonomous channel contention and transmits uplink non-triggered data, please refer to the description of embodiment 4 below. Details will not be described herein. Alternatively, after acquiring a TXOP on the first link through channel contention, the AP MLD transfers the TXOP to the non-AP MLD. In this case, the non-AP MLD is the TXOP holder after the TXOP is transferred. If the AP MLD is to transmit a beacon frame on the second link at the next TBTT and the non-AP MLD determines that the second link is not the same link as the link associated with the current TXOP (i.e., the first link), the non-AP MLD transmits a first frame before a first delay prior to the next TBTT. In this specification, the STA on the link associated with the TXOP (i.e., the first link) needs to know the TSF on the other link to determine the link on which the next TBTT is located. The first frame indicates TXOP termination on the first link. The first frame may be a control frame such as a CF-end frame or a CTS-to-self frame. In response, the AP MLD receives the first frame before the first delay prior to the next TBTT. The non-AP MLD changes the spatial stream on the second link to support beacon frame reception within the first delay after the TXOP termination on the first link. In other words, non-AP MLD must complete the spatial stream change on the second link within the period from the end of the TXOP on the first link to the next TBTT. Alternatively, the period required for non-AP MLD to change the spatial stream to support beacon frame reception must be less than or equal to the first delay.The AP MLD transmits a beacon frame on the second link at the next TBTT. Correspondingly, the non-AP MLD receives the beacon frame by using the spatial stream currently supported on the second link at the next TBTT. It should be understood that the non-AP MLD changes the spatial stream supported on the second link prior to the next TBTT. Therefore, the non-AP MLD can successfully receive the beacon frame at the next TBTT. The first delay is used by the EMLSR non-AP MLD to change the spatial stream on the second link to support beacon frame reception.

[0218] Optionally, the first delay may be further described as the first delay being used by the EMLSR non-AP MLD to switch the receive antenna on the second link to support beacon frame reception.

[0219] In this application, the "next TBTT" is the TBTT that follows the TXOP in time and is closest to the TXOP.

[0220] It should be understood that the first link and the second link in this embodiment of the present application are two different links between the AP MLD and the EMLSR non-AP MLD. In practical application, there may be more links (three or more links) between the non-AP MLD and the AP MLD. The first link represents the link related to the current TXOP among the multiple links between the non-AP MLD and the AP MLD, and the second link represents the link where the next TBTT arrives among the multiple links between the non-AP MLD and the AP MLD.

[0221] Optionally, when non-AP MLD receives on both the first link and the second link by using a single spatial stream (or a single antenna), the reception capacity on one link is limited (i.e., only PPDUs of certain types (i.e., OFDM types and non-HT duplicate types) can be received), and the reception capacity on the other link is not limited (i.e., PPDUs of all types can be received). Alternatively, when non-AP MLD receives on both the first link and the second link by using a single spatial stream (or a single antenna), the reception capacity of both links is limited (i.e., only PPDUs of certain types can be received).

[0222] Optionally, the first delay may be one of EMLSR Delay 1, EMLSR Delay 2, and EMLSR Delay 3 defined in embodiment 1. For details, please refer to the corresponding description of embodiment 1. Details will not be repeated in this specification. For a specific implementation of the first delay, please refer to the corresponding description of embodiment 1. Details will not be repeated in this specification.

[0223] In this embodiment of the present application, in two scenarios where the receiving capability between links is symmetric and asymmetric when non-AP MLD performs receiving by using a single spatial stream (or a single antenna), the impact of EMLSR switching delay on beacon frame reception is considered separately, and it can be seen that the TXOP holder is restricted to end the TXOP before the EMLSR switching delay (i.e., the first delay) prior to the next TBTT to ensure that the non-AP MLD has enough time to complete the switching / changing of the spatial stream (or receiving antenna). This can prevent the non-AP MLD in EMLSR mode from missing important beacon frames.

[0224] In an optional embodiment, the link associated with the current TXOP and the link for transmitting a beacon frame in the next TBTT may be the same link. A first link exists between the TXOP holder non-AP MLD and the AP MLD, and the non-AP MLD is in EMLSR mode. Specifically, it is assumed that the link associated with the current TXOP and the link for transmitting a beacon frame in the next TBTT are the first link. The TXOP holder non-AP MLD transmits a first frame on the first link prior to the next TBTT, and the first frame indicates TXOP termination on the first link. Then, the non-AP MLD maintains the spatial streams supported on the first link or does not change the spatial streams supported on the first link. The AP MLD transmits a beacon frame on the first link in the next TBTT. Correspondingly, the non-AP MLD receives a beacon frame by using the spatial streams currently supported on the first link in the next TBTT. If the non-AP MLD receives on the first link by using a single spatial stream, and reception capability is not limited (i.e., all types of PPDUs can be received), the spatial streams supported on the first link may be a single spatial stream. Alternatively, the spatial streams supported on the first link may be multiple spatial streams. In other words, if the link associated with the current TXOP and the link for transmitting a beacon frame in the next TBTT are the same link, the non-AP MLD may maintain the current spatial streams on the link. That is, the spatial streams supported on the link do not change after the TXOP ends.

[0225] Optionally, the estimated time of TXOP termination must precede the next TBTT, and the time interval between the estimated time of TXOP termination and the next TBTT must be less than or equal to a threshold, for example 64 μs or 128 μs.

[0226] It can be seen that since the link related to the current TXOP and the link for transmitting a beacon frame in the next TBTT are the same link, the non-AP MLD can maintain the current spatial stream and successfully receive a beacon frame in the next TBTT, which can prevent the non-AP MLD in EMLSR mode from missing an important beacon frame.

[0227] Embodiment 3 The third embodiment of the present application mainly describes a link capability indication method when the reception capabilities between non-AP MLD links in EMLSR mode are asymmetric.

[0228] Please refer to Figure 11. Figure 11 is a schematic flowchart of a method for indicating link capability in EMLSR mode according to an embodiment of the present application. As shown in Figure 11, the method for indicating link capability in EMLSR mode includes, but is not limited to, the following steps:

[0229] S301: A non-AP MLD generates a medium access control MAC frame, the MAC frame includes indication information, the indication information indicates an identifier of a link whose receiving capability is not limited when the non-AP MLD receives by using a single spatial stream, or the link information of the link in the MAC frame indicates whether the receiving capability on the link is limited when a single spatial stream is used for receiving.

[0230] S302: The non-AP MLD transmits a MAC frame.

[0231] Optionally, in this embodiment of the present application, when EMLSR non-AP MLD performs reception by using a single spatial stream (or a single antenna), the reception capabilities between the links (or antennas) are asymmetric. From the perspective of spatial streams, EMLSR non-AP MLD includes two types of spatial streams, i.e., a first type spatial stream and a second type spatial stream. When non-AP MLD performs reception on a link by using the first type spatial stream, the reception capabilities are limited. In this case, it can be expressed as only some types of PPDUs (e.g., non-HT overlap types) being able to be received on the link. When non-AP MLD performs reception on the same link by using the second type spatial stream, the reception capabilities are not limited. In this case, it can be expressed as all types of PPDUs being able to be received on the link. From the perspective of antennas, EMLSR non-AP MLD deploys one antenna on each of the two links. One antenna has strong reception capabilities, which can be expressed as the antenna being able to receive all types of PPDUs. The other antenna has weak reception capability, ie, it can only receive PPDUs of some types (eg, non-HT duplicate types).

[0232] Therefore, non-AP MLD may report its antenna status or link capabilities to AP MLD. For ease of explanation, herein, an antenna with strong reception capability is referred to as a regular antenna (regular radio), and an antenna with weak reception capability is referred to as a reduced antenna (reduced radio). It should be understood that the aforementioned first type of spatial stream may be understood as a single spatial stream generated by a limited antenna, and the aforementioned second type of spatial stream may be understood as a single spatial stream generated by a regular antenna. For ease of explanation, herein, when non-AP MLD performs reception on each link by using a single spatial stream (or a single antenna), it should be further understood that a link on which a regular antenna (or a single spatial stream of the second type) is deployed is referred to as a full reception capability link (RX full capability link), and a link on which a limited antenna (or a single spatial stream of the first type) is deployed is referred to as an RX limitation link. It should be further understood that the full reception capability link and the limited reception capability link are not fixed, and the full reception capability link changes as the normal antenna (or the single spatial stream of the second type) is switched between links. For example, from time T1 to time T2, the normal antenna (or the single spatial stream of the second type) operates on link1, and link1 may be referred to as the full reception capability link. From time T2 to time T3, the normal antenna (or the single spatial stream of the second type) is switched to link2 and operates, and link2 may be referred to as the full reception capability link.

[0233] Optionally, the non-AP MLD reports its link capabilities by using indication information in the MAC frame. Specifically, the indication information indicates the identifier of a link whose reception capability is not limited when the non-AP MLD receives by using a single spatial stream (i.e., a full reception capability link). Alternatively, the indication information is carried in the link information of the link in the MAC frame to indicate whether the reception capability on the link is limited when the non-AP MLD receives by using a single spatial stream. The following describes several possible implementations of the indication information.

[0234] In a first embodiment, the indication information is placed in an EHT MAC capabilities information field of the MAC frame, and the length of the indication information may be 1 bit. The EHT MAC capabilities information field is designed for a single STA. Therefore, when 1 bit is added to the EHT MAC capabilities information field to carry the indication information, the indication information indicates whether the receiving capability on the link corresponding to the EHT MAC capabilities information field is limited, or whether the link corresponding to the EHT MAC capabilities information field has full receiving capability.

[0235] Please refer to Figure 12. Figure 12 is a schematic diagram of a frame format of an EHT MAC capability information field according to one embodiment of the present application. As shown in Figure 12, the EHT MAC capability information field includes a full RX capability field and may further include other fields in Figure 12. The full RX capability field (i.e., the aforementioned indication information) is 1 bit in length and indicates whether the receiving capability is limited or whether the link is a full receiving capability link. For example, if the value of the full receiving capability field is 1, it indicates that the receiving capability is not limited or the link is a full receiving capability link, and if the value of the full receiving capability field is 0, it indicates that the receiving capability is limited or the link is not a full receiving capability link. Conversely, if the value of the full receiving capability field is 0, it indicates that the receiving capability is not limited or the link is a full receiving capability link, and if the value of the full receiving capability field is 1, it indicates that the receiving capability is limited or the link is not a full receiving capability link.

[0236] It should be understood that the names, lengths, and arrangement order of all receiving capability fields in the EHT MAC capability information field in Figure 12 are merely examples, which are not limiting in this embodiment of the present application.

[0237] It can be seen that the EHT MAC capability information field is typically conveyed during the association process, and the bit values ​​of the field do not change significantly after the chip leaves the factory, i.e., the capabilities are relatively fixed after shipping, making this scheme relatively static during implementation.

[0238] In a second embodiment, the indication information may be arranged in a per STA Profile of a Multi-Link Element of a MAC frame, and specifically in an STA Control field of the per STA Profile. The length of the indication information may be 1 bit. The per STA Profile includes information about the link. Therefore, when 1 bit is added to the STA Control field of the per STA Profile to carry the indication information, the indication information indicates whether the receiving capability on the link corresponding to the per STA Profile is limited or whether the link corresponding to the per STA Profile is a full receiving capability link.

[0239] Please refer to Figure 13. Figure 13 is a schematic diagram of a frame format of an STA control field according to one embodiment of the present application. As shown in Figure 13, the STA control field includes a full RX capability field and may further include other fields in Figure 13. The full RX capability field (i.e., the aforementioned indication information) is 1 bit in length and indicates whether the receiving capability is limited. For example, if the value of the full RX capability field is 1, it indicates that the receiving capability is not limited, and if the value of the full RX capability field is 0, it indicates that the receiving capability is limited. Conversely, if the value of the full RX capability field is 0, it indicates that the receiving capability is not limited, and if the value of the full RX capability field is 1, it indicates that the receiving capability is limited.

[0240] It should be understood that the names, lengths, and arrangement order of all receive capability fields in the STA control field in Figure 13 are merely examples, which are not limiting in this embodiment of the present application.

[0241] In a third embodiment, the indication information may be placed in a common information field of a multi-link element (Multi-Link Element) of the MAC frame, and may be specifically placed in an enhanced multi-link (EML) capability field of the common information field to indicate an identifier of a link whose reception capability is not limited (or a full reception capability link) when non-AP MLD performs reception by using a single spatial stream. The length of the indication information may be 4 bits.

[0242] Please refer to Figure 14. Figure 14 is a schematic diagram of a frame format of an EML capability field according to an embodiment of the present application. As shown in Figure 14, the EML capability field includes a full RX capability link ID field, and may further include other fields in Figure 14. In order to indicate the identifier of a link whose reception capability is not limited in a 1x1 antenna configuration (or a full reception capability link), the length of the full reception capability link ID field (the aforementioned indication information) is 4 bits.

[0243] It should be understood that the names, lengths, and arrangement order of all receiving capability link identifier fields within the EML capability field in Figure 14 are merely examples, which are not limiting in this embodiment of the present application.

[0244] It can be seen that in this embodiment, the identifier of the link with unlimited reception capability is directly indicated by using 4 bits in the common information field of the Multi-Link Element, and when there are many links between the non-AP MLD and the AP MLD, the bit overhead can be reduced to a certain extent.

[0245] Optionally, the full receiving capability link identifier field in FIG. 14 can indicate only one link whose receiving capability is not limited (i.e., one full receiving capability link). If multiple links whose receiving capability is not limited need to be indicated, a bitmap method can be used for indication. For example, in an 8-bit or 16-bit link bitmap, if the receiving capability on the link identified by the link ID is not limited when a single spatial stream is used for reception, the bit corresponding to the link ID is set to 1. Otherwise, the bit corresponding to the link ID is set to 0, i.e., if the receiving capability on the link identified by the link ID is limited when a single spatial stream is used for reception, the bit corresponding to the link ID is set to 0. Alternatively, the link bitmap is set according to the sequence of the per STA profile in the link information field. For example, the first bit in the link bitmap corresponds to the first per STA profile in the link information field, the second bit in the link bitmap corresponds to the second per STA profile in the link information field, the third bit in the link bitmap corresponds to the third per STA profile in the link information field, and so on. If the receive capability on the link corresponding to the per STA profile is not limited when a single spatial stream is used for reception, the bit in the link bitmap corresponding to the position of the per STA profile is set to 1. For example, if the receive capability on the link corresponding to the fifth per STA profile is not limited when a single spatial stream is used for reception, the fifth bit in the link bitmap is set to 1.

[0246] It can be seen that since a bitmap is added to the common information field of the multilink element, multiple links whose reception capabilities are not limited can be indicated. If a non-AP MLD has multiple links whose reception capabilities are not limited, the bit overhead can be reduced to a certain extent. For example, if there are five links between the non-AP MLD and the AP MLD and a single spatial stream is used for reception, the reception capabilities on two of the links are not limited. In this case, only a 5-bit bitmap needs to be added to the common information field of the multilink element, and the identifiers of the two links do not need to be indicated separately by using 8 bits.

[0247] S303: The AP MLD receives the MAC frame.

[0248] S304: AP MLD parses the MAC frame.

[0249] Optionally, the AP MLD receives the MAC frame and parses the MAC to obtain indication information in the MAC frame. A link on which reception capability is not limited when the non-AP MLD receives by using a single spatial stream for reception is determined based on the indication of the indication information. Alternatively, whether reception capability on a link is limited when a single spatial stream is used for reception is determined based on the indication of the indication information.

[0250] Optionally, after determining the links on which reception capabilities are not limited, the AP MLD may transmit broadcast frames or unicast management frames on the links on which reception capabilities are not limited.

[0251] In this embodiment of the present application, it can be seen that the non-AP MLD actively reports the link capabilities of the non-AP MLD. When the AP MLD acts as a TXOP holder, beacon frame transmission between the AP MLD and the EMLSR non-AP MLD can be supported. In addition, when communicating with the EMLSR non-AP MLD, the AP MLD may not transmit initial control frames on links with unlimited reception capabilities, reducing the overhead of some initial control frames.

[0252] The above-described third embodiment describes that non-AP MLD reports its link capabilities (or antenna capabilities) to AP MLD in an explicit indication manner. In an optional embodiment, non-AP MLD may also report its link capabilities to AP MLD in an implicit indication manner. Specifically, AP MLD and non-AP MLD may, by default, consider that the link over which association request frames and association response frames are exchanged is a link whose reception capability is not limited when non-AP MLD performs reception by using a single spatial stream (i.e., a full reception capability link). Alternatively, the standard specifies that the link over which association request frames and association response frames are exchanged is a link whose reception capability is not limited when non-AP MLD performs reception by using a single spatial stream (i.e., a full reception capability link). When a Reassociation Request frame and a Reassociation Response frame are subsequently exchanged, if the original link with no limited receiving capabilities (i.e., the original full receiving capability link) does not lose its association during the reassociation, the link with no limited receiving capabilities in this case is still the original link with no limited receiving capabilities (i.e., the link between which the Association Request frame and the Association Response frame are exchanged). If the original link with no limited receiving capabilities loses its association during the reassociation, the link with no limited receiving capabilities (i.e., the full receiving capability link) becomes the link between which the Reassociation Request frame and the Reassociation Response frame are exchanged.Alternatively, when a reassociation request frame and a reassociation response frame are subsequently exchanged, the link whose receiving capability is not limited when non-AP MLD performs reception by using a single spatial stream may be directly updated to the link on which the reassociation request frame and the reassociation response frame are exchanged. It should be understood that if the link on which the association request frame and the association response frame are exchanged and the link on which the reassociation request frame and the reassociation response frame are exchanged are the same link, the link whose receiving capability is not limited (i.e., the full receiving capability link) may not need to be updated.

[0253] In this embodiment of the present application, it can be seen that the non-AP MLD informs the AP MLD of the link capabilities (or supported spatial streams or supported antenna capabilities) of the non-AP MLD in an implicit indication manner, reducing signaling overhead.

[0254] In another optional embodiment, the AP MLD may further specify a link for which reception capability is not limited (i.e., may specify the link as a full reception capability link). In reality, the AP MLD does not know the specific link for which reception capability is not limited when the non-AP MLD performs reception by using a single spatial stream. After the AP MLD specifies the link, the non-AP MLD needs to switch to the link for which reception capability is not limited, designated as a single spatial stream / normal antenna, based on the instruction of the AP MLD. For example, the AP MLD indicates the link for which reception capability is not limited by using the instruction information. After receiving the instruction information, the non-AP MLD switches to the link for which reception capability is not limited, designated as a single spatial stream / normal antenna, designated by the instruction information.

[0255] In this embodiment of the present application, it can be seen that the AP MLD directly indicates the links on which the non-AP MLDs do not have limited reception capabilities. This facilitates scheduling when the AP MLD communicates with multiple EMLSR non-AP MLDs. For example, the AP MLD may specify the same link as the link on which the non-AP MLDs do not have limited reception capabilities for multiple EMLSR non-AP MLDs, so that the AP MLD and multiple EMLSR non-AP MLDs transmit management frames on the same link.

[0256] Embodiment 4 Embodiment 4 of the present application mainly describes how EMLSR non-AP MLD transmits uplink non-trigger-based data, that is, how to transmit uplink data independently.

[0257] Please refer to Figure 15. Figure 15 is a schematic flowchart of an uplink non-trigger-based data transmission method in EMLSR mode according to an embodiment of the present application. As shown in Figure 15, the uplink non-trigger-based data transmission method in EMLSR mode includes, but is not limited to, the following steps:

[0258] S401: A non-AP MLD performs channel contention on a first link to obtain a TXOP, and the spatial stream on the first link is a single spatial stream.

[0259] S402: The non-AP MLD maintains channel occupancy on the first link and switches spatial streams on the second link to the first link to form multiple spatial streams.

[0260] S403: The non-AP MLD sends an uplink PPDU on the first link by using multiple spatial streams.

[0261] Optionally, in this embodiment of the present application, a STA on a link with limited reception capability is enabled to perform autonomous channel contention, for example, Enhanced Distributed Channel Access (EDCA). After the STA acquires the channel through contention, if the STA can transmit a single-stream data frame, the STA transmits the single-stream data frame or switches the receive antenna on another link to the link associated with the TXOP, and then transmits a multi-stream data frame. If the STA cannot transmit a single-stream data frame, the STA needs to switch the spatial stream (or antenna) on another link to the link associated with the TXOP to form multiple spatial streams (or multiple antennas) to transmit uplink non-trigger-based data. This embodiment of the present application is mainly for cases where non-AP MLD needs to switch spatial streams (or antennas).

[0262] Optionally, the non-AP MLD performs channel contention on the first link by using a single spatial stream (or a single antenna) to obtain a TXOP. If the non-AP MLD cannot transmit a single-stream data frame on the first link or wants to transmit a multi-stream data frame, the non-AP MLD maintains channel occupancy on the first link and switches the spatial streams on the second link to the first link to form multiple spatial streams (multiple antennas) to ensure that the non-AP MLD can transmit the multi-stream data frame. In other words, the non-AP MLD needs to complete spatial stream (antenna) switching before transmitting an uplink PPDU. Therefore, after completing spatial stream (antenna) switching, the non-AP MLD can transmit an uplink PPDU on the first link by using multiple spatial streams (or multiple antennas). How the non-AP MLD maintains channel occupancy on the first link can be designed according to actual circumstances. The following describes several possible ways of maintaining channel occupancy using examples.

[0263] Scheme 1: Please refer to Figure 16a. Figure 16a is a sequence diagram 1 of an uplink non-trigger-based data transmission method according to an embodiment of the present application. As shown in Figure 16a, after preempting the channel on link1 (i.e., the first link mentioned above), STA1 in the non-AP MLD transmits an RTS frame by using a single spatial stream and starts switching the spatial stream (or antenna) after receiving a CTS frame. In this case, AP1 in the AP MLD needs to pad the CTS frame so that the non-AP MLD has enough time to switch the single spatial stream (or single antenna) on link2 (i.e., the second link mentioned above) to link1 to form a dual spatial stream (or dual spatial stream) to support the subsequent uplink PPDU transmission by the non-AP MLD on link1. The EMLSR delay1 in Figure 16a represents the time required to switch a single spatial stream (or a single antenna) on one link to another link to form multiple spatial streams (or multiple antennas). It should be understood that the length of the padding may be determined based on EMLSR delay1. The CTS frame needs to be transmitted by using a PPDU of at least the HT format (including the HT format, the VHT format, the HE format, and the EHT format). Correspondingly, the RTS frame also needs to be transmitted by using a PPDU of at least the HT format.

[0264] Scheme 2: Please refer to Figure 16b. Figure 16b is a sequence diagram 2 of an uplink non-trigger-based data transmission method according to an embodiment of the present application. As shown in Figure 16b, after pre-empting the channel on link1 (i.e., the first link mentioned above), STA1 in the non-AP MLD transmits an RTS frame by using a single spatial stream and then starts switching the spatial stream (or antenna), or switches the spatial stream / antenna simultaneously (or in parallel) when transmitting the RTS frame (i.e., starts switching the spatial stream / antenna when transmitting the RTS frame). In this case, STA1 in the non-AP MLD needs to pad the RTS frame so that the non-AP MLD has enough time to switch the single spatial stream (or single antenna) on link2 (i.e., the second link mentioned above) to link1 to form multiple spatial streams (or multiple antennas) to support the subsequent uplink PPDU transmission by the non-AP MLD on link1. 16b represents the time required to switch a single spatial stream (or a single antenna) on one link to another link to form multiple spatial streams (or multiple antennas). It should be understood that the length of padding can be determined based on the EMLSR delay1. The RTS frame needs to be transmitted by using at least an HT-format PPDU, or STA1 transmits a multi-user (MU) RTS (i.e., MU-RTS) frame and pads the MU-RTS frame. Optionally, if AP1 cannot send a CTS frame because it is transmitting, STA1 switches the spatial stream (or antenna) on link1 back to the original antenna configuration, i.e., switches back to a single spatial stream (or a single antenna) on link1 and link2.

[0265] Scheme 3: See Figure 16c. Figure 16c is a sequence diagram 3 of an uplink non-trigger-based data transmission method according to an embodiment of the present application. As shown in Figure 16c, after pre-empting the channel on link1 (i.e., the first link mentioned above), STA1 in the non-AP MLD transmits an RTS frame by using a single spatial stream and then starts switching the spatial stream (or antenna), or switches the spatial stream / antenna simultaneously (or in parallel) when transmitting the RTS frame (i.e., starts switching the spatial stream / antenna when transmitting the RTS frame). After receiving the CTS frame returned by AP1 in the AP MLD, STA1 in the non-AP MLD transmits another RTS frame to maintain channel occupancy.

[0266] In this embodiment of the present application, it can be seen that non-AP MLD in EMLSR mode is supported to transmit uplink non-trigger-based data, since non-AP MLD in EMLSR mode is further enabled to perform autonomous contention.

[0267] In one optional embodiment, since STAs on links with limited receiver capabilities can only understand (or receive / parse) some PPDUs, allowing STAs to compete actually impacts contention within a BSS, which is more likely to incur collisions. Therefore, if EMLSR non-AP MLD receiver capabilities are asymmetric between links, the standard may specify that only STAs on links with no receiver capabilities limitations can compete for the channel (e.g., using EDCA). Alternatively, AP MLD specifies that STAs on a link may engage in channel contention to transmit uplink non-triggered data. In this embodiment of the present application, non-AP MLD in EMLSR mode may be restricted to channel contention only on some links (e.g., links with no receiver capabilities limitations or some links specified by AP MLD) to transmit uplink non-triggered data, which may be found to reduce collisions in channel contention.

[0268] The foregoing describes in detail the method provided in the present application. To facilitate the implementation of the foregoing solutions in the embodiments of the present application, the embodiments of the present application further provide corresponding apparatuses or devices.

[0269] In the embodiment of the present application, the AP MLD and non-AP MLD may be divided into functional modules based on the above-mentioned exemplary method. For example, each functional module may be obtained by dividing the functional modules based on their respective functions, or two or more functions may be integrated into one processing module. The integrated module may be implemented in the form of hardware or in the form of a software functional module. Note that in the embodiment of the present application, the division into modules is an example and is merely a logical division of functions. In actual implementation, other divisions may be used. The following describes in detail a communication device in the embodiment of the present application with reference to Figures 17 to 19. The communication device may be an AP MLD or a non-AP MLD. Furthermore, the communication device may be a device in an AP MLD, or a device in a non-AP MLD.

[0270] If an integrated unit is used, please refer to Figure 17. Figure 17 is a schematic diagram illustrating the structure of a communication device 1 according to an embodiment of the present application. The communication device 1 may be an AP MLD or a chip within the AP MLD, for example a Wi-Fi chip. As shown in Figure 17, the communication device 1 includes a transceiver unit 11 and optionally includes a processing unit 12.

[0271] In a first design, the transceiver unit 11 is configured to transmit a first frame before a first delay prior to the next TBTT, where the first frame indicates the end of the TXOP on the first link and the first delay is used by the non-AP MLD to change the spatial stream on the second link to support beacon frame reception. The transceiver unit 11 is further configured to transmit a beacon frame on the second link at the next TBTT. The first link and the second link exist between the TXOP holder communication device 1 and the EMLSR non-AP MLD, and the communication device 1 is to transmit a beacon frame on the second link at the next TBTT.

[0272] Optionally, the processing unit 12 is configured to generate the first frame and the beacon frame.

[0273] Optionally, the transceiver unit 11 is further configured to receive a second frame, the second frame including indication information, the indication information indicating an identifier of a link whose reception capability is not limited when non-AP MLD performs reception by using a single spatial stream.

[0274] Optionally, the transceiver unit 11 is further configured to receive a second frame, the second frame including indication information, the indication information being carried in link information of the link to indicate whether reception capability on the link is limited when a single spatial stream is used for reception.

[0275] It should be understood that the communication device 1 in the first design may perform the embodiment 1 correspondingly, and the above-mentioned operations or functions of the units in the communication device 1 are respectively used to implement the corresponding operations of AP MLD in embodiment 1. For brevity, the details will not be described again in this specification.

[0276] In a second design, the transceiver unit 11 is configured to receive a first frame before a first delay prior to the next TBTT, the first frame indicating the end of the TXOP on the first link, and the first delay being used by the non-AP MLD to change spatial streams on the second link to support beacon frame reception. The transceiver unit 11 is further configured to transmit a beacon frame on the second link at the next TBTT. The first link and the second link exist between the communication device 1 and the TXOP holder non-AP MLD, and the non-AP MLD is in EMLSR mode.

[0277] Optionally, the processing unit 12 is configured to generate a beacon frame.

[0278] It should be understood that the communication device 1 in the second design may perform the embodiment 2 correspondingly, and the aforementioned operations or functions of the units in the communication device 1 are respectively used to implement the corresponding operations of the AP MLD in the embodiment 2. For the sake of brevity, the details will not be described again in this specification.

[0279] In a third design, transceiver unit 11 is configured to receive a MAC frame, the MAC frame including indication information, where the indication information indicates an identifier of a link whose reception capability is not limited when non-AP MLD performs reception by using a single spatial stream, or link information of the link in the MAC frame indicates whether reception capability on the link is limited when a single spatial stream is used for reception. Processing unit 12 is configured to parse the MAC frame.

[0280] It should be understood that the communication device 1 in the third design may perform the third embodiment correspondingly, and the aforementioned operations or functions of the units in the communication device 1 are respectively used to implement the corresponding operations of the AP MLD in the third embodiment. For the sake of brevity, the details will not be described again in this specification.

[0281] Please refer to Figure 18. Figure 18 is a schematic diagram illustrating the structure of a communication device 2 according to an embodiment of the present application. The communication device 2 may be a non-AP MLD or a chip in a non-AP MLD, such as a Wi-Fi chip. As shown in Figure 18, the communication device 2 includes a transceiver unit 21 and a processing unit 22.

[0282] In a first design, the transceiver unit 21 is configured to receive a first frame before a first delay prior to the next TBTT, the first frame indicating the end of a TXOP on the first link, and the first delay being used by the non-AP MLD to change the spatial stream on the second link to support beacon frame reception. The switching subunit 221 in the processing unit 22 is configured to change the spatial stream on the second link to support beacon frame reception within the first delay after the end of the TXOP on the first link. The transceiver unit 21 is further configured to receive a beacon frame by using the spatial stream currently supported on the second link at the next TBTT. A first link and a second link exist between the communication device 2 and the TXOP holder AP MLD.

[0283] Optionally, the receiving capability is limited when the communication device 2 receives on the first link and on the second link by using a single spatial stream. The spatial streams supported on the first link within the TXOP are multiple spatial streams, but no spatial streams are supported on the second link of the communication device 2 within the TXOP. The switching subunit 221 is specifically configured to change from supporting no spatial streams to supporting multiple spatial streams on the second link within a first delay after the end of the TXOP on the first link.

[0284] Optionally, the communication device 2 includes a first spatial stream and a second spatial stream, and when the communication device 2 receives on the link by using the first spatial stream, the reception capacity is limited, and when the communication device 2 receives on the link by using the second spatial stream, the reception capacity is not limited.

[0285] Optionally, the spatial streams supported on the first link in the TXOP are multiple spatial streams including a first spatial stream and a second spatial stream. However, no spatial streams are supported on the second link of the communication device 2 in the TXOP. If the communication device 2 receives on the second link by using a single spatial stream, the reception capability is not limited. The switching subunit 221 is specifically configured to change from not supporting spatial streams to supporting a single spatial stream on the second link within a first delay after the end of the TXOP on the first link. The single spatial stream supported on the second link supports beacon frame reception. In this specification, the second spatial stream supported on the first link in the TXOP may be returned to the second link.

[0286] In one embodiment, the spatial streams supported on the first link in the TXOP are multiple spatial streams including a first spatial stream and a second spatial stream. However, if no spatial streams are supported on the second link of the communication device 2 in the TXOP, and the communication device 2 receives on the second link by using a single spatial stream, the reception capability is limited. The switching subunit 221 is specifically configured to change from supporting no spatial streams on the second link to supporting a single spatial stream within a first delay after the end of the TXOP on the first link. The single spatial stream supported on the second link supports beacon frame reception. In this specification, the second spatial stream supported on the first link can be switched to the second link.

[0287] In another embodiment, the spatial stream supported on the second link of the communication device 2 within the TXOP is a single spatial stream, but the reception capability is limited when the communication device 2 receives on the second link by using the single spatial stream. The switching subunit 221 is specifically configured to change the spatial stream supported on the second link from a single spatial stream to multiple spatial streams within a first delay after the end of the TXOP on the first link.

[0288] In one embodiment, the transceiver unit 21 is further configured to transmit a second frame, the second frame including indication information, the indication information indicating an identifier of a link whose reception capability is not limited when non-AP MLD performs reception by using a single spatial stream.

[0289] In another embodiment, the transceiver unit 21 is further configured to transmit a second frame, the second frame including indication information, the indication information being carried in link information of the link to indicate whether reception capability on the link is limited when a single spatial stream is used for reception.

[0290] It should be understood that the communication device 2 in the first design may perform the embodiment 1 correspondingly, and the aforementioned operations or functions of the units in the communication device 2 are respectively used to implement the corresponding operations of non-AP MLD in embodiment 1. For brevity, the details will not be described again in this specification.

[0291] In a second design, the transceiver unit 21 is configured to transmit a first frame before a first delay prior to the next TBTT, where the first frame indicates the end of a TXOP on the first link, and the first delay is used by the communication device 2 to change the spatial stream on the second link to support beacon frame reception. A switching subunit 221 in the processing unit 22 is configured to change the spatial stream on the second link to support beacon frame reception within the first delay after the end of the TXOP on the first link. The transceiver unit 21 is further configured to receive a beacon frame by using the spatial stream currently supported on the second link at the next TBTT. The first link and the second link exist between the communication device 2 and the TXOP holder AP MLD. The communication device 2 is in an EMLSR mode.

[0292] Optionally, the receiving capability is limited when the communication device 2 receives on the first link and on the second link by using a single spatial stream. The spatial streams supported on the first link within the TXOP are multiple spatial streams, but no spatial streams are supported on the second link of the communication device 2 within the TXOP. The switching subunit 221 is specifically configured to change from supporting no spatial streams to supporting multiple spatial streams on the second link within a first delay after the end of the TXOP on the first link.

[0293] Optionally, the communication device 2 includes a first spatial stream and a second spatial stream, and when the communication device 2 receives on the link by using the first spatial stream, the reception capacity is limited, and when the communication device 2 receives on the link by using the second spatial stream, the reception capacity is not limited.

[0294] Optionally, the spatial streams supported on the first link in the TXOP are multiple spatial streams including a first spatial stream and a second spatial stream. However, no spatial streams are supported on the second link of the communication device 2 in the TXOP. If the communication device 2 receives on the second link by using a single spatial stream, the reception capability is not limited. The switching subunit 221 is specifically configured to change from not supporting spatial streams to supporting a single spatial stream on the second link within a first delay after the end of the TXOP on the first link. The single spatial stream supported on the second link supports beacon frame reception. In this specification, the second spatial stream supported on the first link in the TXOP may be returned to the second link.

[0295] In one embodiment, the spatial streams supported on the first link in the TXOP are multiple spatial streams including a first spatial stream and a second spatial stream. However, if no spatial streams are supported on the second link of the communication device 2 in the TXOP, and the communication device 2 receives on the second link by using a single spatial stream, the reception capability is limited. The switching subunit 221 is specifically configured to change from supporting no spatial streams on the second link to supporting a single spatial stream within a first delay after the end of the TXOP on the first link. The single spatial stream supported on the second link supports beacon frame reception. In this specification, the second spatial stream supported on the first link can be switched to the second link.

[0296] In another embodiment, the spatial stream supported on the second link of the communication device 2 within the TXOP is a single spatial stream, but the reception capability is limited when the communication device 2 receives on the second link by using the single spatial stream. The switching subunit 221 is specifically configured to change the spatial stream supported on the second link from a single spatial stream to multiple spatial streams within a first delay after the end of the TXOP on the first link.

[0297] In one embodiment, the transceiver unit 21 is further configured to transmit a second frame, the second frame including indication information, the indication information indicating an identifier of a link whose reception capability is not limited when non-AP MLD performs reception by using a single spatial stream.

[0298] In another embodiment, the transceiver unit 21 is further configured to transmit a second frame, the second frame including indication information, the indication information being carried in link information of the link to indicate whether reception capability on the link is limited when a single spatial stream is used for reception.

[0299] It should be understood that the communication device 2 in the second design may perform the second embodiment correspondingly, and the aforementioned operations or functions of the units in the communication device 2 are respectively used to implement the corresponding operations of non-AP MLD in the second embodiment. For brevity, the details will not be described again in this specification.

[0300] In a third design, generating subunit 222 in processing unit 22 is configured to generate a medium access control (MAC) frame, the MAC frame including indication information, where the indication information indicates an identifier of a link whose reception capability is not limited when non-AP MLD receives by using a single spatial stream, or link information of the link in the MAC frame indicates whether reception capability on the link is limited when a single spatial stream is used for reception. The transceiver unit is configured to transmit the MAC frame.

[0301] It should be understood that the communication device 2 in the third design may perform the third embodiment correspondingly, and the aforementioned operations or functions of the units in the communication device 2 are respectively used to implement the corresponding operations of non-AP MLD in the third embodiment. For brevity, the details will not be described again in this specification.

[0302] In a fourth design, a channel contention subunit 223 in the processing unit 22 is configured to perform channel contention on the first link to obtain a TXOP, maintain channel occupancy on the first link, and the spatial stream on the first link is a single spatial stream. A switching subunit 221 in the processing unit 22 is configured to switch the spatial stream on the second link to the first link to form multiple spatial streams. The transceiver unit 21 is configured to transmit an uplink PPDU on the first link by using the multiple spatial streams.

[0303] It should be understood that the communication device 2 in the second design may correspondingly perform embodiment 10, and the aforementioned operations or functions of the units in the communication device 2 are respectively used to implement the corresponding operations of non-AP MLD in embodiment 4. For brevity, the details will not be described again in this specification.

[0304] The above describes AP MLD and non-AP MLD in the embodiments of the present application. The following describes possible product forms of AP MLD and non-AP MLD. It should be understood that any form of product having the functions of the AP MLD in Figure 17 and any form of product having the functions of the AP MLD and non-AP MLD in Figure 18 fall within the scope of protection of the embodiments of the present application. It should be further understood that the following description is merely an example, and the product forms of AP MLD and non-AP MLD in the embodiments of the present application are not limited thereto.

[0305] As a possible product form, the AP MLD and non-AP MLD described in the embodiments of the present application may be implemented by using a common bus architecture.

[0306] For ease of explanation, please refer to FIG. 19. FIG. 19 is a schematic diagram illustrating the structure of a communication device 1000 according to one embodiment of the present application. The communication device 1000 may be an AP MLD or a non-AP MLD, or may be a chip within an AP MLD or a non-AP MLD. FIG. 19 shows only the main components of the communication device 1000. In addition to the processor 1001 and the transceiver 1002, the communication device may further include a memory 1003 and an input / output device (not shown).

[0307] The processor 1001 is primarily configured to process communication protocols and communication data, control communication devices, execute software programs, and process data from the software programs. The memory 1003 is primarily configured to store software programs and data. The transceiver 1002 may include control circuitry and an antenna. The control circuitry is primarily configured to convert between baseband signals and radio frequency signals and process the radio frequency signals. The antenna is primarily configured to receive and transmit radio frequency signals in the form of electromagnetic waves. The input / output devices, such as a touchscreen, display, and keyboard, are primarily configured to receive data entered by a user and output data to the user.

[0308] After the communication device is powered on, the processor 1001 can read the software program in the memory 1003, interpret and execute the instructions of the software program, and process data of the software program. When data needs to be transmitted wirelessly, the processor 1001 performs baseband processing on the data to be transmitted and then outputs a baseband signal to the radio frequency circuit. The radio frequency circuit performs radio frequency processing on the baseband signal and then transmits the radio frequency signal in the form of an electromagnetic wave via an antenna. When data is to be transmitted to the communication device, the radio frequency circuit receives the radio frequency signal via the antenna, converts the radio frequency signal to a baseband signal, and outputs the baseband signal to the processor 1001. The processor 1001 converts the baseband signal to data and processes the data.

[0309] In another embodiment, the radio frequency circuitry and antenna may be located independently from the processor that performs the baseband processing, for example, in a distributed scenario, the radio frequency circuitry and antenna may be located remotely and independently from the communication device.

[0310] The processor 1001, the transceiver 1002, and the memory 1003 may be connected via a communication bus.

[0311] In one design, communications apparatus 1000 may be configured to perform the functionality of AP MLD in embodiment 1. Processor 1001 may be configured to generate the first frame transmitted in step S101 and the beacon frame transmitted in step S104 of FIG. 5 , and / or perform other processes of the techniques described herein. Transceiver 1002 may be configured to perform steps S101 and S104 of FIG. 5 , and / or perform other processes of the techniques described herein.

[0312] In another design, communication device 1000 may be configured to perform the functionality of non-AP MLD in embodiment 1. Processor 1001 may be configured to perform step S103 of FIG. 5 and / or other processes of the techniques described herein. Transceiver 1002 may be configured to perform step S102 and step S105 of FIG. 5 and / or other processes of the techniques described herein.

[0313] In one design, communications apparatus 1000 may be configured to perform the functionality of AP MLD in embodiment 2. Processor 1001 may be configured to generate a beacon frame transmitted in step S204 of FIG. 10 and / or perform other processes of the techniques described herein. Transceiver 1002 may be configured to perform steps S202 and S204 of FIG. 10 and / or perform other processes of the techniques described herein.

[0314] In another design, communications device 1000 may be configured to perform the functionality of non-AP MLD in embodiment 2. Processor 1001 may be configured to perform step S203 of FIG. 10 and / or other processes of the techniques described herein. Transceiver 1002 may be configured to perform step S201 and step S205 of FIG. 10 and / or other processes of the techniques described herein.

[0315] In one design, communications apparatus 1000 may be configured to perform the AP MLD functionality of embodiment 3. Processor 1001 may be configured to perform step S304 of FIG. 11 and / or other processes of the techniques described herein. Transceiver 1002 may be configured to perform step S303 of FIG. 11 and / or other processes of the techniques described herein.

[0316] In another design, communications apparatus 1000 may be configured to perform the functionality of non-AP MLD in embodiment 3. Processor 1001 may be configured to perform step S301 of FIG. 11 and / or other processes of the techniques described herein. Transceiver 1002 may be configured to perform step S302 of FIG. 11 and / or other processes of the techniques described herein.

[0317] In one design, communications apparatus 1000 may be configured to perform the functionality of non-AP MLD in embodiment 4. Processor 1001 may be configured to perform steps S401 and S402 of FIG. 15 and / or other processes of the techniques described herein. Transceiver 1002 may be configured to perform step S403 of FIG. 15 and / or other processes of the techniques described herein.

[0318] In any one of the aforementioned designs, the processor 1001 may include a transceiver configured to perform receiving and transmitting functions. For example, the transceiver may be a transceiver circuit, an interface, or an interface circuit. The transceiver circuit, interface, or interface circuit configured to perform receiving and transmitting functions may be separate or integrated with each other. The transceiver circuit, interface, or interface circuit may be configured to read and write code / data. Alternatively, the transceiver circuit, interface, or interface circuit may be configured to transmit or forward signals.

[0319] In any one of the aforementioned designs, the processor 1001 may store instructions. The instructions may be a computer program. The computer program executes on the processor 1001, thereby enabling the communication device 1000 to perform the method described in any one of the aforementioned method embodiments. The computer program may be fixed within the processor 1000. In this case, the processor 1001 may be implemented by hardware.

[0320] In one embodiment, the communications device 1000 may include circuitry that may perform the transmit, receive, or communication functions in the aforementioned method embodiments. The processors and transceivers described herein may be implemented in integrated circuits (ICs), analog ICs, radio frequency integrated circuits (RFICs), mixed-signal ICs, application specific integrated circuits (ASICs), printed circuit boards (PCBs), electronic devices, etc. The processors and transceivers may alternatively be fabricated using various IC technologies, such as complementary metal oxide semiconductor (CMOS), n-type metal oxide semiconductor (NMOS), p-type metal oxide semiconductor (PMOS), bipolar junction transistor (BJT), bipolar CMOS (BiCMOS), silicon germanium (SiGe), and gallium arsenide (GaAs).

[0321] The scope of the communication device described in this application is not limited in this respect, and the structure of the communication device may not be limited by FIG. 14. The communication device may be a standalone device or part of a larger device. For example, the communication device may be: (1) A standalone integrated circuit IC, chip, or chip system or subsystem; (2) a set including one or more ICs, optionally the IC set may further include a storage component configured to store data and computer programs; (3) ASIC, e.g., modem, (4) a module that can be embedded in another device; (5) Receivers, terminals, intelligent terminals, mobile phones, wireless devices, handheld devices, mobile units, in-vehicle devices, network devices, cloud devices, artificial intelligence devices, etc., or (6) Another device, etc.

[0322] In one possible product form, the AP MLD and non-AP MLD in the embodiments of the present application may be implemented by a general-purpose processor.

[0323] A general-purpose processor for implementing AP MLD includes a processing circuit and an input / output interface interconnected to and communicating with the processing circuit.

[0324] In one design, the general-purpose processor may be configured to perform the functionality of the AP MLD in embodiment 1. Specifically, the processing circuit may be configured to generate the first frame transmitted in step S101 and the beacon frame transmitted in step S104 of FIG. 5, and / or other processes of the techniques described herein. The input / output interface may be configured to perform step S101 and step S104 of FIG. 5, and / or other processes of the techniques described herein.

[0325] In another design, the general-purpose processor may be configured to perform the functionality of the AP MLD in embodiment 2. Specifically, the processing circuit may be configured to generate the beacon frame transmitted in step S204 of FIG. 10 and / or other processes of the techniques described herein. The input / output interface may be configured to perform steps S202 and S204 of FIG. 10 and / or other processes of the techniques described herein.

[0326] In one design, a general-purpose processor may be configured to perform the functionality of the AP MLD in embodiment 3. Specifically, the processing circuit may be configured to perform step S304 of FIG. 11 and / or other processes of the techniques described herein. The input / output interface may be configured to perform step S303 of FIG. 11 and / or other processes of the techniques described herein.

[0327] A general-purpose processor for implementing non-AP MLD includes a processing circuit and an input / output interface interconnected to and communicating with the processing circuit.

[0328] In one design, the general-purpose processor may be configured to perform the functionality of the non-AP MLD in embodiment 1. Specifically, the processing circuit may be configured to perform step S103 of FIG. 5 and / or other processes of the techniques described herein. The input / output interface may be configured to perform step S102 and step S105 of FIG. 5 and / or other processes of the techniques described herein.

[0329] In one design, a general-purpose processor may be configured to perform the functionality of non-AP MLD in embodiment 2. Specifically, the processing circuit may be configured to perform step S203 of FIG. 10 and / or other processes of the techniques described herein. The input / output interface may be configured to perform step S201 and step S205 of FIG. 10 and / or other processes of the techniques described herein.

[0330] In one design, a general-purpose processor may be configured to perform the functionality of non-AP MLD in embodiment 3. Specifically, the processing circuit may be configured to perform step S301 of FIG. 11 and / or other processes of the techniques described herein. The input / output interface may be configured to perform step S302 of FIG. 11 and / or other processes of the techniques described herein.

[0331] In one design, the general-purpose processor may be configured to perform the functionality of the non-AP MLD in embodiment 4. Specifically, the processing circuit may be configured to perform step S401 and step S402 of FIG. 15 and / or other processes of the techniques described herein. The input / output interface may be configured to perform step S403 of FIG. 15 and / or other processes of the techniques described herein.

[0332] It should be understood that the communication devices in the various product forms mentioned above have any function of AP MLD or non-AP MLD in the method embodiments, and the details will not be repeated here.

[0333] An embodiment of the present application further provides a computer-readable storage medium, which stores computer program code, which, when executed by a processor, causes the electronic device to perform the method in any one of the preceding embodiments.

[0334] An embodiment of the present application further provides a computer program product, which, when run on a computer, enables the computer to perform the method in any one of the preceding embodiments.

[0335] An embodiment of the present application further provides a communication device. The device may exist in the form of a chip product. The structure of the device includes a processor and an interface circuit. The processor is configured to communicate with another device via the interface circuit to enable the device to perform the method in any one of the previous embodiments.

[0336] An embodiment of the present application further provides a wireless communication system including an AP MLD and a non-AP MLD, wherein the AP MLD and the non-AP MLD can perform the method in any one of the foregoing embodiments.

[0337] The method or algorithm steps described in connection with the content disclosed herein may be implemented by hardware or by a processor executing software instructions. The software instructions may include corresponding software modules. The software modules may be stored in random access memory (RAM), flash memory, erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), registers, a hard disk, a removable hard disk, a compact disk read-only memory (CD-ROM), or any other form of storage medium known in the art. For example, the storage medium may be coupled to the processor such that the processor can read information from and write information to the storage medium. Of course, the storage medium may be components of the processor. The processor and the storage medium may be located in an ASIC. In addition, the ASIC may be located in the core network interface device. Of course, the processor and the storage medium may reside as separate components in the core network interface device.

[0338] Those skilled in the art will understand that in one or more of the foregoing examples, the functions described in this application may be implemented by hardware, software, firmware, or any combination thereof. If the functions are implemented by software, they may be stored on or transmitted as one or more instructions or code on a computer-readable medium. Computer-readable media include computer-readable storage media and communication media. Communication media include any medium that facilitates the transmission of a computer program from one place to another. Storage media may be any available medium accessible by a general-purpose or special-purpose computer.

[0339] In the above specific embodiments, the objectives, technical solutions and beneficial effects of the present application are further described in detail. It should be understood that the above description is only a specific embodiment of the present application and is not intended to limit the protection scope of the present application. Any modifications, equivalent replacements, improvements, etc. made based on the technical solutions of the present application shall fall within the protection scope of the present application. [Explanation of symbols]

[0340] 100 AP MLD 200 non-AP MLD 300 non-AP MLD 400 STA 1. Communications equipment 11 Transceiver unit 12 Processing Unit 2. Communications equipment 21 Transceiver unit 22 Processing Unit 221 Switching Subunit 222 Generation subunit 223 Channel Contention Subunit 1000 Communication Equipment 1001 processor 1002 Transceiver 1003 memory

Claims

1. A beacon frame transmission method in an enhanced multi-link single-radio EMLSR mode, comprising: a first link and a second link exist between a transmit opportunity TXOP holder access point multilink device AP MLD and an enhanced multilink single-radio EMLSR non-access point multilink device non-AP MLD, and the AP MLD is to transmit a beacon frame on the second link at a next target beacon transmission time TBTT, the method comprising: transmitting, by the AP MLD, a first frame before a first delay prior to a next TBTT, the first frame indicating an end of a TXOP on the first link, and the first delay being used by the non-AP MLD to change spatial streams on the second link to support beacon frame reception; transmitting a beacon frame on the second link at the next TBTT according to the AP MLD; A method comprising:

2. A beacon frame transmission method in EMLSR mode, comprising: There are a first link and a second link between the EMLSR non-AP MLD and the TXOP holder AP MLD, and the method includes: receiving, by the non-AP MLD, a first frame before a first delay prior to a next TBTT, the first frame indicating an end of a TXOP on the first link, the first delay being used by the non-AP MLD to change spatial streams on the second link to support beacon frame reception; changing the spatial streams on the second link to support beacon frame reception by the non-AP MLD within the first delay after the TXOP on the first link ends; receiving a beacon frame by using the spatial streams supported on the second link at the next TBTT via the non-AP MLD; A method comprising:

3. the first delay is a period of time required for the non-AP MLD to change the spatial streams supported on the second link from a single spatial stream to multiple spatial streams; or The first delay is a period of time required for the non-AP MLD to change from supporting no spatial streams on the second link to supporting a single spatial stream or multiple spatial streams.

3. The method according to claim 1 or 2, wherein the method is one of:

4. When the non-AP MLD receives on the second link by using a single spatial stream, reception capability is limited, and spatial streams are not supported on the second link for the non-AP MLD in the TXOP; The step of changing the spatial streams on the second link to support beacon frame reception by the non-AP MLD within the first delay after the TXOP on the first link ends includes: changing from supporting no spatial streams to supporting multiple spatial streams on the second link by the non-AP MLD within the first delay after the TXOP ends on the first link.

4. The method of claim 3, comprising:

5. No spatial stream is supported on the second link of the non-AP MLD in the TXOP; The step of changing the spatial streams on the second link to support beacon frame reception by the non-AP MLD within the first delay after the TXOP on the first link ends includes: changing from supporting no spatial streams to supporting a single spatial stream on the second link by the non-AP MLD within the first delay after the TXOP ends on the first link, the single spatial stream supported on the second link supports beacon frame reception.

4. The method of claim 3, comprising:

6. When the non-AP MLD receives on the second link by using a single spatial stream, reception capability is limited, and the spatial stream supported on the second link of the non-AP MLD in the TXOP is a single spatial stream; The step of changing the spatial streams on the second link to support beacon frame reception by the non-AP MLD within the first delay after the TXOP on the first link ends includes: changing the spatial streams supported on the second link from a single spatial stream to multiple spatial streams by the non-AP MLD within the first delay after the TXOP on the first link ends.

4. The method of claim 3, comprising:

7. A link whose reception capability is not limited when the non-AP MLD receives by using a single spatial stream is a link where association request frames and association response frames are exchanged between the AP MLD and the non-AP MLD in an association process, or a link where re-association request frames and re-association response frames are exchanged between the AP MLD and the non-AP MLD in a re-association process.

3. The method according to claim 1 or 2.

8. The method comprises: transmitting a second frame by the non-AP MLD before receiving the first frame, the second frame including instruction information, the instruction information indicating an identifier of a link whose reception capability is not limited when the non-AP MLD performs reception by using a single spatial stream, so that the reception capability is not limited when the non-AP MLD performs reception by using a single spatial stream; 3. The method of claim 2, further comprising:

9. The method comprises: receiving a second frame by the AP MLD before transmitting the first frame, the second frame including instruction information, the instruction information indicating an identifier of a link whose reception capability is not limited when the non-AP MLD performs reception by using a single spatial stream, so that the reception capability is not limited when the non-AP MLD performs reception by using a single spatial stream; The method of claim 1 further comprising:

10. The method according to claim 8 or 9, wherein the indication information is placed in a common information field of a multilink element of the second frame, and the length of the indication information is 4 bits.

11. The method of claim 10 , wherein the instruction information is placed in an Extended MultiLink EML Capabilities field of the common information field.

12. The method comprises: transmitting a second frame by the non-AP MLD before receiving the first frame, the second frame including indication information, the indication information being carried in link information of the link to indicate whether reception capability on the link is limited when a single spatial stream is used for reception, so that reception capability is not limited when the non-AP MLD performs reception by using a single spatial stream; 3. The method of claim 2, further comprising:

13. The method comprises: receiving a second frame by the AP MLD before transmitting the first frame, the second frame including indication information, the indication information being carried in link information of the link to indicate whether reception capability on a link is limited when a single spatial stream is used for reception, so that reception capability is not limited when the non-AP MLD performs reception by using a single spatial stream; The method of claim 1 further comprising:

14. The method according to claim 12 or 13, wherein the indication information is placed in an Ultra High Throughput EHT Medium Access Control MAC Capability Information field of the second frame, and the length of the indication information is 1 bit.

15. The method according to claim 12 or 13, wherein the indication information is arranged in a profile for each station STA of a multilink element of the second frame, and the length of the indication information is 1 bit.

16. The method of claim 15, wherein the instruction information is placed in a STA control field of a profile for each station STA.

17. A beacon frame transmission method in EMLSR mode, comprising: a first link and a second link exist between a TXOP holder non-AP MLD and an AP MLD, the non-AP MLD is in an EMLSR mode, and the method includes: transmitting, by the non-AP MLD, a first frame before a first delay prior to a next TBTT, the first frame indicating an end of a TXOP on the first link, and the first delay being used by the non-AP MLD to change spatial streams on the second link to support beacon frame reception; changing the spatial streams on the second link to support beacon frame reception by the non-AP MLD within the first delay after the TXOP on the first link ends; receiving a beacon frame by using the spatial streams supported on the second link at the next TBTT via the non-AP MLD; A method comprising:

18. A beacon frame transmission method in EMLSR mode, comprising: a first link and a second link exist between an AP MLD and a TXOP holder non-AP MLD, the non-AP MLD is in an EMLSR mode, and the method includes: receiving, by the AP MLD, a first frame before a first delay prior to a next TBTT, the first frame indicating an end of a TXOP on the first link, the first delay being used by the non-AP MLD to change spatial streams on the second link to support beacon frame reception; transmitting a beacon frame on the second link at the next TBTT according to the AP MLD; A method comprising:

19. the first delay is a period of time required for the non-AP MLD to change the spatial streams supported on the second link from a single spatial stream to multiple spatial streams; or The first delay is a period of time required for the non-AP MLD to change from supporting no spatial streams on the second link to supporting a single spatial stream or multiple spatial streams.

19. The method according to claim 17 or 18, wherein the method is one of

20. When the non-AP MLD receives on the second link by using a single spatial stream, reception capability is limited, and spatial streams are not supported on the second link for the non-AP MLD in the TXOP; The step of changing the spatial streams on the second link to support beacon frame reception by the non-AP MLD within the first delay after the TXOP on the first link ends includes: changing from supporting no spatial streams to supporting multiple spatial streams on the second link by the non-AP MLD within the first delay after the TXOP ends on the first link.

20. The method of claim 19, comprising:

21. No spatial stream is supported on the second link of the non-AP MLD in the TXOP; The step of changing the spatial streams on the second link to support beacon frame reception by the non-AP MLD within the first delay after the TXOP on the first link ends includes: changing from supporting no spatial streams to supporting a single spatial stream on the second link by the non-AP MLD within the first delay after the TXOP ends on the first link, the single spatial stream supported on the second link supports beacon frame reception.

20. The method of claim 19, comprising:

22. When the non-AP MLD receives on the second link by using a single spatial stream, reception capability is limited, and the spatial stream supported on the second link of the non-AP MLD in the TXOP is a single spatial stream; The step of changing the spatial streams on the second link to support beacon frame reception by the non-AP MLD within the first delay after the TXOP on the first link ends includes: changing the spatial streams supported on the second link from a single spatial stream to multiple spatial streams by the non-AP MLD within the first delay after the TXOP on the first link ends.

20. The method of claim 19, comprising:

23. A link whose reception capability is not limited when the non-AP MLD receives by using a single spatial stream is a link where association request frames and association response frames are exchanged between the AP MLD and the non-AP MLD in an association process, or a link where re-association request frames and re-association response frames are exchanged between the AP MLD and the non-AP MLD in a re-association process.

19. The method of claim 17 or 18.

24. 19. A communication device comprising a unit or module configured to perform the method of claim 1 or 2 or 17 or 18.

25. 19. A communications device comprising a processor and a transceiver, the transceiver configured to transmit and receive frames, and the processor configured to execute program instructions to enable the communications device to perform a method according to claim 1 or 2 or 17 or 18.

26. 19. A computer-readable storage medium having stored thereon program instructions that, when executed on a computer, enable the computer to perform the method of claim 1 or 2 or 17 or 18.

27. 19. A computer program product comprising program instructions, which when executed on a computer enable the computer to perform the method of claim 1 or 2 or 17 or 18.

28. A communication device including a processor and an interface circuit, the interface circuitry is configured to receive code instructions and transmit the code instructions to the processor; 19. A communications device, wherein the processor is configured to execute the code instructions to perform the method of claim 1 or 2 or 17 or 18.

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