Communication methods and devices

Abstract

Embodiments of the present application relate to a communication method and apparatus. The method includes the following: an AP MLD receives first downlink data from the current AL MLD, the first downlink data is encrypted using a first key, the first key is a key negotiated by the current AP MLD and a non-AP MLD, the target AP MLD is the AP MLD of a non-AP MLD after a transition of the basic service set BSS, and the target AP MLD performs lower media access control LMAC layer processing and physical layer processing on the first downlink data to obtain second downlink data. According to the method and apparatus of the present application, the roaming performance of a non-AP MLD can be improved.

Description

Technical Field

[0001] Embodiments of the present application are related to the field of communication technologies, particularly to communication methods and devices.

Background Art

[0002] [[ID=I1]] Due to factors such as the movement of a non-access point (non-AP) multi-link device (MLD), the non-AP MLD needs to switch the access point (AP) MLD associated with the non-AP MLD. During roaming, the non-AP MLD is often affected by a rate decrease (specifically, a decrease in the transmission rate). How to improve the roaming performance of the non-AP MLD is an important research guideline for next-generation wireless fidelity (Wi-Fi) roaming.

Summary of the Invention

[0003] Embodiments of the present application provide a communication method and a device. During roaming, data transmission is performed between the current AP MLD and the target AP MLD, which can improve the roaming performance of the non-AP MLD.

[0004] In accordance with the first aspect, a communication method is provided, comprising: a target access point AP multilink device MLD receiving first downlink data transmitted by the current AP MLD, the first downlink data being encrypted using a first key, the first key being a key negotiated by the current AP MLD and a non-access point non-AP MLD, the target AP MLD being the AP MLD of the non-AP MLD after a transition of the basic service set BSS; the target AP MLD performing lower medium access control LMAC layer processing and physical layer processing on the first downlink data to obtain second downlink data; and the target AP MLD transmitting the second downlink data to the non-AP MLD.

[0005] A second aspect is provided, a communication method comprising: a target access point (AP) multilink device (MLD) receiving first uplink data transmitted by a non-access point (non-AP) MLD, the first uplink data being encrypted using a first key, the first key being a key negotiated by the current AP MLD and the non-AP MLD, the target AP MLD being the AP MLD of the non-AP MLD after a transition of the basic service set (BSS); the target AP MLD performing physical layer processing and lower medium access control (LMAC) layer processing on the first uplink data to determine second uplink data; and the target AP MLD transmitting the second uplink data to the current AP MLD.

[0006] In the design, a first transmission link exists between the non-AP MLD and the current AP MLD, and the method further includes the target AP MLD receiving a first request, the first request being used to request the establishment of a second transmission link between the non-AP MLD and the target AP MLD, and the target AP MLD establishing the second transmission link with the non-AP MLD.

[0007] In the design, the first request contains instruction information to enable dual-link transmission of non-AP MLD, and the dual-link includes a first transmission link and a second transmission link.

[0008] In the design, the method further includes the target AP MLD sending a second request to the current AP MLD. The second request is used to request that dual-link transmission be enabled for the non-AP MLD, and the second request includes the maximum MAC Layer Protocol Data Unit (MPDU) length supported by the target AP MLD, and / or the maximum number of aggregated MAC Layer Service Data Units (MSDUs) allowed by the target AP MLD.

[0009] In the design, the method further includes the following: the target AP MLD receives a third request, which is used to request that a path switch be triggered for the non-AP MLD; and the target AP MLD sends a fourth request to the distributed system DS, which is used to request the DS to update the stored mapping relationship between the non-AP MLD and the current AP MLD to the mapping relationship between the non-AP MLD and the target AP MLD.

[0010] In the design, one or both of the first and third requests are transmitted by a non-AP MLD, and one or both of the first and third requests are transmitted via the air interface between the non-AP MLD and the target AP MLD, or via the current AP MLD and DS.

[0011] In the design, when the first request is transmitted via the current AP MLD and DS, the first request does not include operating channel information (OCI).

[0012] In the design, after the target AP MLD receives the third request and before the target AP MLD sends the fourth request to the DS, the method further includes the target AP MLD sending a context transfer request to the current AP MLD and the target AP MLD receiving the context transfer response sent by the current AP MLD. The context transfer response contains context information for the non-AP MLD.

[0013] In the design, the context forwarding response further includes at least one of the following: a block acknowledgment protocol for the traffic identifier TID, the window start position of the transmission buffer for the TID, the window size of the transmission buffer for the TID, the window start position of the uplink receive end scoreboard, the window size of the uplink receive end scoreboard, the window start position of the receive sort buffer, the window size of the receive sort buffer, the currently received maximum packet number PN value, or the uplink replay counter.

[0014] In the design, after the non-AP MLD's transmission path is switched from the first transmission path to the second transmission path, the non-AP MLD and the target AP MLD encrypt / decrypt the uplink data and / or downlink data using a second key negotiated by the non-AP MLD and the target AP MLD.

[0015] In accordance with the third aspect, a communication method is provided, comprising: a current access point (AP) multilink device (MLD) receiving third downlink data transmitted by a distributed system (DS); the current AP MLD encrypting the third downlink data using a first key to obtain first downlink data, the first key being a key negotiated by the current AP MLD and a non-access point (non-AP MLD); and the current AP MLD transmitting the first downlink data to a target AP MLD, the target AP MLD being the AP MLD of a non-AP MLD after a transition of the basic service set (BSS).

[0016] A fourth aspect is provided, a communication method comprising: a current access point (AP) multilink device (MLD) receiving second uplink data transmitted by a target AP MLD, the target AP MLD being the AP MLD of a non-access point (non-AP MLD) after a transition of the basic service set (BSS); the current AP MLD performing higher medium access control (UMAC) layer processing on the second uplink data, decrypting the second uplink data using a first key to determine the third uplink data, the first key being a key negotiated by the current AP MLD and the non-AP MLD; and the current AP MLD transmitting the third uplink data to a distributed system (DS).

[0017] In the design, a first transmission link exists between the current AP MLD and the non-AP MLD, and the method further includes the current AP MLD receiving a second request sent by the target AP MLD, the second request being used to request the non-AP MLD to enable dual-link transmission, the second request including the maximum Media Access Control MAC Layer Protocol Data Unit (MPDU) length supported by the target AP MLD, and / or the maximum number of aggregated MAC Layer Service Data Units (MSDUs) allowed by the target AP MLD, and the dual-link includes the first transmission link and the second transmission link between the non-AP MLD and the target AP MLD.

[0018] In the design, the method further includes the current AP MLD receiving a fifth request sent by a non-AP MLD, the fifth request being used to request the disconnection of the first transmission link between the non-AP MLD and the current AP MLD, the fifth request including first instruction information, the first instruction information instructing the current AP MLD to reserve the non-AP MLD's block acknowledgment BA information and / or context information and buffer data not sent by the non-AP MLD, and the current AP MLD sending a sixth request to the DS, the sixth request being used to request the deletion of the mapping relationship between the non-AP MLD and the current AP MLD that is stored in the DS.

[0019] In the design, the method further includes the current AP MLD receiving a context transfer request sent by the target AP MLD, and the current AP MLD sending a context transfer response to the target AP MLD. The context transfer response contains context information for the non-AP MLD.

[0020] In the design, the context forwarding response further includes at least one of the following: a block acknowledgment protocol for the traffic identifier TID, the window start position of the transmission buffer for the TID, the window size of the transmission buffer for the TID, the window start position of the uplink receive end scoreboard, the window size of the uplink receive end scoreboard, the window start position of the receive sort buffer, the window size of the receive sort buffer, the currently received maximum packet number PN value, or the uplink replay counter.

[0021] In the design, the method further includes the current AP MLD sending a beacon measurement request to a non-AP MLD. The beacon measurement request includes instruction information for the corresponding link of the serving AP.

[0022] In the design, the method further includes the current AP MLD sending a seventh request to the non-AP MLD. The seventh request includes second instruction information, which instructs the non-AP MLD to reserve BA information and / or context information and buffer any data not yet sent by the non-AP MLD.

[0023] A fifth aspect is provided, a communication method comprising: a non-access point (non-AP) multilink device (MLD) receiving data transmitted by the current access point (AP) MLD by using a target access point (AP) MLD, the target AP MLD being the AP MLD of the non-AP MLD after a transition of the basic service set (BSS); the data being encrypted by the current AP MLD by using a first key, the first key being a key negotiated by the current AP MLD and the non-access point (non-AP) MLD; and the non-AP MLD decrypting the data by using the first key.

[0024] According to a sixth aspect, there is provided a communication method, in which a non-access point non-AP multi-link device MLD encrypts uplink data to be transmitted by using a first key to determine first uplink data, and the first key is a key negotiated by a current access point AP MLD and the non-AP MLD, and the non-AP MLD transmits the first uplink data to the current AP MLD by using a target AP MLD, and the target AP MLD is an AP MLD of the non-AP MLD after a transition of a basic service set BSS.

[0025] In a design, a first transmission link exists between the non-AP MLD and the current AP MLD, and the method further includes the non-AP MLD transmitting a first request, and the first request is used to request to establish a second transmission link between the non-AP MLD and the target AP MLD.

[0026] In a design, the first request includes indication information for enabling dual-link transmission of the non-AP MLD, and the dual-link includes the first transmission link and the second transmission link.

[0027] In a design, the method further includes the non-AP MLD transmitting a third request. The third request is used to request to trigger path switching of the non-AP MLD. <00,00087>

[0028] In a design, one or both of the first request and the third request are transmitted to the target AP MLD, and one or both of the first request and the third request are transmitted via an air interface between the non-AP MLD and the target AP MLD, or are transmitted via the current AP MLD and a DS. [[ID=:18]]

[0029] In the design, when the first request is transmitted through the current AP MLD and DS, the first request does not include operating channel information OCI.

[0030] In the design, the method further includes that the non-AP MLD transmits the fifth request to the current AP MLD. The fifth request includes the first indication information, and the first indication information reserves the block acknowledgment BA information and / or context information of the non-AP MLD, and instructs the current AP MLD to buffer the data not transmitted by the non-AP MLD.

[0031] In the design, the method further includes that the non-AP MLD receives the beacon measurement request transmitted by the current AP MLD. The beacon measurement request includes the indication information of the corresponding link of the serving AP.

[0032] In the design, the method further includes that the non-AP MLD receives the seventh request transmitted by the current AP MLD. The seventh request includes the second indication information, and the second indication information reserves the BA information and / or context information of the non-AP MLD, and instructs the non-AP MLD to buffer the data not transmitted by the non-AP MLD.

[0033] In the design, after the transmission path of the non-AP MLD is switched from the first transmission path to the second transmission path, the non-AP MLD and the target AP MLD encrypt / decrypt the uplink data and / or downlink data by using the second key negotiated by the non-AP MLD and the target AP MLD.

[0034] In the design, in the foregoing aspect, the data is transmitted or received in a transparent transmission mode between the current AP MLD and the target AP MLD.

[0035] An apparatus is provided according to the seventh aspect. The apparatus may implement the methods of the first or second aspect. For example, the apparatus includes means corresponding to the first or second aspect. The apparatus may be implemented by hardware, by software, or by hardware running corresponding software.

[0036] In the design, the apparatus includes a unit that performs either a first or second aspect.

[0037] In the design, the device includes a processor and memory. The processor is configured to execute computer programs or instructions stored in memory, enabling the device to implement the method in the first aspect or the second aspect.

[0038] In the design, the device includes a processor and interface circuits. The interface circuits are configured to receive signals from other devices and transmit those signals to the processor, and to transmit signals from the processor to other devices. The processor is configured to implement the methods in the first or second aspect by using logic circuits or by executing code instructions.

[0039] An apparatus is provided in accordance with the eighth aspect. The apparatus may implement the methods of the third or fourth aspect. For example, the apparatus includes means corresponding to the third or fourth aspect. The apparatus may be implemented by hardware, by software, or by hardware running corresponding software.

[0040] In the design, the apparatus includes a unit that performs a third or fourth aspect.

[0041] In the design, the device includes a processor and memory. The processor is configured to execute computer programs or instructions stored in memory, enabling the device to implement the method in the third or fourth aspect.

[0042] In the design, the device includes a processor and interface circuits. The interface circuits are configured to receive signals from other devices and transmit those signals to the processor, and to transmit signals from the processor to other devices. The processor is configured to implement the methods of the third or fourth aspect by using logic circuits or by executing code instructions.

[0043] An apparatus is provided in accordance with the ninth aspect. The apparatus may implement the methods of the fifth or sixth aspect. For example, the apparatus includes means corresponding to the fifth or sixth aspect. The apparatus may be implemented by hardware, by software, or by hardware running corresponding software.

[0044] In the design, the apparatus includes a unit that performs a fifth or sixth aspect.

[0045] In the design, the device includes a processor and memory. The processor is configured to execute computer programs or instructions stored in memory so that the device can implement the method in the fifth or sixth aspect.

[0046] In the design, the device includes a processor and interface circuits. The interface circuits are configured to receive signals from other devices and transmit those signals to the processor, and to transmit signals from the processor to other devices. The processor is configured to implement the methods of the fifth or sixth aspect by using logic circuits or by executing code instructions.

[0047] In accordance with the tenth aspect, a computer-readable storage medium storing a computer program or instruction is provided. When the computer program or instruction is executed by the computer, the computer may implement the method in any one of the first through sixth aspects.

[0048] A computer program product is provided, which includes a computer program or instructions, in accordance with the eleventh aspect. When the computer program or instructions are executed on a computer, the method of any one of the first through sixth aspects is performed.

[0049] A chip including a processor is provided in accordance with the twelfth aspect. The processor is coupled to memory and configured to execute computer programs or instructions stored in memory so that the chip can implement the method in any one of the first through sixth aspects.

[0050] In accordance with the thirteenth aspect, a communication system is provided including a first communication device, a second communication device, and a third communication device. The first communication device is configured to implement the method in the first or second aspect, the second communication device is configured to implement the method in the third or fourth aspect, and the third communication device is configured to implement the method in the fifth or sixth aspect. [Brief explanation of the drawing]

[0051] [Figure 1] This is a diagram of a multilink device (MLD) according to an embodiment of the present application. [Figure 2] This is a diagram of an application scenario according to an embodiment of the present invention. [Figure 3] This is a flowchart of downlink data transmission according to an embodiment of the present invention. [Figure 4A] This is a diagram illustrating the processing of downlink data according to an embodiment of the present application. [Figure 4B]This is a diagram illustrating the processing of downlink data according to an embodiment of the present application. [Figure 5] This is a flowchart of uplink data transmission according to an embodiment of the present invention. [Figure 6A] This is a diagram illustrating the processing of uplink data according to an embodiment of the present application. [Figure 6B] This is a diagram illustrating the processing of uplink data according to an embodiment of the present application. [Figure 7a] This is a flowchart of roaming switching according to an embodiment of the present invention. [Figure 7b] This is a diagram of a message format according to an embodiment of the present application. [Figure 7c] This is a diagram of a message format according to an embodiment of the present application. [Figure 8] This is another flowchart of roaming switching according to the embodiment of the present application. [Figure 9] This is a diagram of a message format according to an embodiment of the present application. [Figure 10] This is a diagram of a message format according to an embodiment of the present application. [Figure 11] This is a diagram of a message format according to an embodiment of the present application. [Figure 12] This is a diagram showing the structure of the apparatus according to the present invention. [Figure 13] This is a diagram showing the structure of the apparatus according to the present invention. [Modes for carrying out the invention]

[0052] To further clarify the purpose, technical solutions, and advantages of the embodiments of this application, the embodiments will be described in detail below with reference to the accompanying drawings. Specific operating methods, functional descriptions, etc., in the method embodiments can also be applied to apparatus embodiments and system embodiments.

[0053] Embodiments of this application may be applicable to wireless local area network (WLAN) systems, and may be applicable to Institute of Electrical and Electronics Engineers (IEEE) 802.11 protocols such as 802.11be, 802.11bf, and future 802.11 protocols used in WLANs. The methods provided in embodiments of this application may be implemented by communication devices in wireless communication systems, or by chips, circuits, etc., used in communication devices. Accordingly, the communication devices support communication by IEEE 802.11 series protocols. While embodiments of this application are primarily described using a network deployed by IEEE 802.11 as an example, those skilled in the art will readily understand that aspects of embodiments of this application can be extended to other networks using various standards or protocols, such as Bluetooth, high-performance radio local area networks (LANs) (HIPERLAN) (a wireless standard similar to the IEEE 802.11 standard, mainly used in Europe), wide area networks (WANs), WLANs, personal area networks (PANs), or other known or subsequently developed networks. The technical solutions in embodiments of this application may be applied to various cellular communication systems, such as fifth-generation (5G) systems, new radio (NR) systems, and future sixth-generation (6G) systems.

[0054] Multilink technology is sometimes used in IEEE 802.11 Next Generation Wireless Fidelity (Wi-Fi) Extremely High Throughput (EHT) to improve transmission rates. Devices with multilink aggregation capabilities are called multi-link devices (MLDs). In design, an MLD can mean that a device has multiple radio frequency modules operating simultaneously on different bands / channels. If the distance between the channels on which two radio frequency modules within a single device operate is sufficiently large, the two radio frequency modules can operate independently without interfering with each other. For any two links, if it is possible to transmit on one link and receive on the other link simultaneously, the two links are considered to support simultaneous transmit and receive (STR) capability. Conversely, if it is not possible to transmit on one link and receive on the other link simultaneously, the two links are considered not to support simultaneous transmit and receive capability. In other words, non-STR transmission and reception is occurring on the two links.

[0055] MLDs can include non-access point (non-AP) MLDs and / or access point (AP) MLDs. Non-AP MLDs are sometimes also called station (STA) MLDs. Non-AP MLDs and AP MLDs can communicate with each other. As shown in Figure 1, an MLD (e.g., AP MLD or non-AP MLD) can include a physical layer (PHY) (PHY#1, PHY#2, and PHY#n shown in Figure 1) and a medium access control (MAC) layer. The physical layer can be used to process physical layer signals, and the MAC layer can be used to process MAC layer signals. Furthermore, the MAC layer can be further divided into one upper-MAC (UMAC) layer (upper MAC shown in Figure 1) and multiple lower-MAC (LMAC) layers (lower MAC#1, and lower MAC#2 to lower MAC#n shown in Figure 1). As shown in Figure 1, multiple APs included in an AP MLD are independent of each other at the lower MAC layer and PHY, but share the upper MAC layer. Multiple STAs included in a non-AP MLD are independent of each other at the lower MAC layer and PHY, but share the upper MAC layer. The upper MAC layer is individually connected to multiple lower MAC layers. In other words, the upper MAC layer is shared by multiple links. For example, the upper MAC layer primarily performs operations such as sequence number (SN) assignment, packet number (PN) assignment, and encryption / decryption for MAC service data units (MSDUs). For example, the lower MAC layer primarily performs operations such as assembly of MAC protocol data units (MPDUs) of the lower MAC layer links, channel access, and packet transmission / reception acknowledgment.

[0056] In Figure 1, the PHY#1 layer, lower MAC#1 layer, and upper MAC layer within the AP MLD can be considered as AP#1, the PHY#2 layer, lower MAC#2 layer, and upper MAC layer can be considered as AP#2, and the PHY#n layer, lower MAC#n layer, and upper MAC layer can be considered as AP#n. In other words, an AP MLD can be understood to contain n AP entities. The same applies to non-AP MLDs. Specifically, the upper MAC layer within a non-AP MLD is also shared by multiple links, and the PHY#1 layer, lower MAC#1 layer, and upper MAC layer can be considered as STA#1, the PHY#2 layer, lower MAC#2 layer, and upper MAC layer can be considered as STA#2, and the PHY#n layer, lower MAC#n layer, and upper MAC layer can be considered as STA#n. In other words, a non-AP MLD can be understood to contain n STA entities. As shown in Figure 1, PHY#1 of AP#1 in the AP MLD and PHY#1 of STA#1 in the non-AP MLD operate on the same channel, and AP#1 in the AP MLD and STA#1 in the non-AP MLD communicate via a link (for example, link #1 shown in Figure 1). PHY#2 of AP#2 in the AP MLD and PHY#2 of STA#2 in the non-AP MLD operate on different but the same channel, and AP#2 in the AP MLD and STA#2 in the non-AP MLD communicate via a link (for example, link #2 shown in Figure 1). PHY#n of AP#n in the AP MLD and PHY#n of STA#n in the non-AP MLD operate on different but the same channel, and AP#n in the AP MLD and STA#n in the non-AP MLD communicate via a link (for example, link #n shown in Figure 1).

[0057] In embodiments of the present invention, a non-AP MLD may switch the AP MLD associated with it due to factors such as movement. For example, as a non-AP MLD moves, it moves from the coverage area of ​​AP MLD1 to the coverage area of ​​AP MLD2. Therefore, the AP MLD associated with the non-AP MLD may need to be switched. In the design, during switching, the non-AP MLD disconnects the old link with the current AP MLD and then establishes a new link with the target AP MLD. The transmission link is interrupted. Therefore, the switching process carries the risk of rate degradation. In the solution of embodiments of the present invention, the non-AP MLD first establishes a second link to the target AP MLD, and the non-AP MLD and the current AP MLD are still transmitting data. Then, at some point, the non-AP MLD disconnects the first transmission link with the current AP MLD. During the switching process, the non-AP MLD can simultaneously transmit data to the current AP MLD and the target AP MLD based on its multilink capability. Throughout the switching process, the non-AP MLD always maintains a transmission link, and not all transmission links are interrupted. In this way, the risk of rate degradation during the switching process is reduced.

[0058] In the solutions provided in the embodiments of the present invention, when dual connectivity transmission is enabled during the switching or roaming operation of a non-AP MLD, for downlink transmission, the current AP MLD must transparently transmit encrypted data to the target AP MLD, and after receiving the encrypted data, the target AP MLD delivers the encrypted data directly to the target AP MLD's lower MAC for transmission. For uplink transmission, the target AP MLD transparently transmits the data received by the lower MAC layer to the current AP MLD, and after receiving the data, the current AP MLD delivers the data directly to the current AP MLD's higher MAC for subsequent processing, such as decryption. After the non-AP MLD has completed switching, i.e., after roaming has completed, specifically, when the transmission link of the non-AP MLD has switched from the current AP MLD to the target AP MLD, the target AP MLD may perform encryption / decryption by using a key negotiated with the target AP MLD (hereinafter referred to as the second key).

[0059] As shown in Figure 2, a communication system is provided. The communication system includes non-AP MLD and AP MLD.

[0060] In this embodiment of the present application, the non-AP MLD may be a device having wireless transceiver functionality. For example, the non-AP MLD may be a terminal device, user equipment (UE), access terminal, subscriber unit, subscriber station, mobile station, remote station, remote terminal, mobile device, user terminal, wireless communication device, user agent, or user equipment. During specific applications, non-AP MLD may include cellular phones, mobile phones, tablet computers (pads), wearable devices, smart point-of-sale (POS) machines, customer-premises equipment (CPE), computers with wireless transceiver capabilities, virtual reality (VR) terminals, augmented reality (AR) terminals, terminal devices in industrial control, terminal devices in self-driving, terminal devices in telemedicine, terminal devices in smart grids, terminal devices in smart cities, terminals in smart homes, and so on.

[0061] In this embodiment of the present application, a non-AP MLD may include multiple links, each corresponding to a different STA entity, and the multiple STA entities are independent of each other at the lower MAC and PHY layers, but share the upper MAC layer. The multiple STA entities typically operate on different bands or channels. In the example in Figure 2, the non-AP MLD includes two STA entities, which are referred to as STA1 and STA2, respectively. Both STA1 and STA2 may operate on the 2.4G and 5G bands, respectively. At any given moment, STA1 and STA2 may operate on different bands.

[0062] In Figure 2, the AP MLD may be AP MLD1 and / or AP MLD2. In this embodiment of the present application, the AP MLD is a device such as a wireless hub or router configured to provide wireless network access services, and the non-AP MLD may function as an access point for entering a wired Ethernet backbone.

[0063] Similar to non-AP MLDs, AP MLDs can contain multiple links, each corresponding to a different AP entity. These AP entities are independent of each other at the lower MAC and PHY layers, but share the upper MAC layer. Multiple AP entities typically operate on different bands or channels. In the example in Figure 2, AP MLD1 and AP MLD2 each contain two entities called AP1 and AP2, respectively. AP1 and AP2 operate on different bands. AP1 operates in the 2.4GHz band, and AP2 operates in the 5GHz band.

[0064] In the design, before switching or roaming, the non-AP MLD is associated with AP MLD1, which is referred to as the current AP MLD. Specifically, as shown in Figure 2, STA1 operates in the 2.4 GHz band and establishes a link with AP1. STA2 operates in the 5 GHz band and establishes a link with AP2.

[0065] Due to factors such as movement, the non-AP MLD moves outside the coverage area of ​​the current AP MLD, i.e., AP MLD1, and enters the coverage area of ​​the target AP MLD (i.e., AP MLD2). During the switching or roaming process, transmission links are established between the non-AP MLD and the current AP MLD (i.e., AP MLD1) and the target AP MLD (i.e., AP MLD2), respectively. Specifically, as shown in Figure 2, during the switching or roaming process, STA2 in the non-AP MLD may disconnect its link with AP2 in the current AP MLD, and STA2 will establish a link with AP1 in the target AP MLD. As mentioned above, the two STAs in the non-AP MLD can operate in the 2.4GHz or 5GHz band. In the example in Figure 2, STA2 operates in the 2.4GHz band and establishes a link with AP1 in the target AP MLD.

[0066] At some point, a non-AP MLD can be completely switched from the current AP MLD to the target AP MLD. In the example in Figure 2, STA1 in the non-AP MLD disconnects its link with the current AP MLD and establishes a link with the AP in the target AP MLD. In the example in Figure 2, STA1 disconnects its link with the current AP MLD, operates in the 5GHz band, and establishes a link with AP2 in the target AP MLD.

[0067] As shown in Figure 2, after the switching or roaming of the non-AP MLD is completed, the non-AP MLD will access the target AP MLD. Specifically, STA1 in the non-AP MLD establishes a link with AP2 in the target AP MLD, and STA2 establishes a link with AP1 in the target AP MLD.

[0068] In possible implementations, the communication system shown in Figure 2 may further include other non-AP MLDs and / or other AP MLDs, other devices, etc. This is not limited. For example, the communication system may further include a distributed system (DS). In implementation, a DS can interconnect multiple basic service sets (BSSs) and incorporate systems of the local area network to form an extended service set (ESS). In other words, a DS can constitute an ESS, and an ESS includes multiple interconnected BSSs. Alternatively, it may be stated as: a DS includes multiple interconnected BSSs, etc. A BSS is the basic part of a local area network (LAN) 802.11. A BSS includes STAs that are associated and located within the coverage area. For example, an AP MLD may include multiple AP entities, each AP entity corresponding to one BSS, and each BSS corresponding to an AP entity may include at least one STA, and multiple STAs are associated with the AP entities corresponding to the BSSs. Before switching or roaming, in downlink data transmission, the DS may transfer downlink data to the current AP MLD, and the current AP MLD transmits the downlink data to the non-AP MLD. In uplink data transmission, the non-AP MLD may transmit uplink data to the current AP MLD, and the current AP MLD distributes the uplink data to the DS. After switching or roaming is complete, in downlink data transmission, the DS may transfer downlink data to the target AP MLD, and the target AP MLD transmits the downlink data to the non-AP MLD. In uplink data transmission, the non-AP MLD may transmit uplink data to the target AP MLD, and the target AP MLD distributes the uplink data to the DS. During the switching or roaming process, transmission links are established between the non-AP MLD and the current AP MLD and the target AP MLD, respectively.Please refer to the following explanation for the processes of uplink and downlink data transmission.

[0069] In this embodiment of the present application, during a switching or roaming process, uplink data or downlink data may be transmitted between a non-AP MLD and a target AP MLD. During the transmission of uplink or downlink data, the data transmission between the non-AP MLD and the target AP MLD is encrypted / decrypted using a first key, which is a key negotiated by the non-AP MLD and the current AP MLD.

[0070] In the following description, in downlink and uplink data transmission, a first transmission link exists between the non-AP MLD and the current AP MLD, and a second link exists between the non-AP MLD and the target AP MLD. Before the non-AP MLD roams or switches over, the first transmission link is established between the non-AP MLD and the current AP MLD. During roaming or switching over, a second transmission link may be established between the non-AP MLD and the target AP MLD. See the following description for the process of establishing the second transmission link. It should be noted that in this embodiment of the present application, the switching or roaming of the non-AP MLD may also be referred to as the non-AP MLD's BSS transition. The current AP MLD may be referred to as the AP MLD of the non-AP MLD before the BSS transition, and the target AP MLD may be referred to as the AP MLD of the non-AP MLD after the BSS transition, and so on.

[0071] [Downlink Data Transmission]

[0072] In the design, during downlink data transmission, the current AP MLD receives the third downlink data transmitted by the DS. The first downlink data is obtained through processing at the higher MAC level of the current AP MLD. During encryption at the higher MAC level, the third downlink data is encrypted using the first key. The current AP MLD sends the first downlink data to the target AP MLD, which performs lower MAC layer processing and physical layer processing on the first downlink data to obtain the second downlink data. The target AP MLD sends the second downlink data to the non-AP MLD.

[0073] As shown in Figure 3, the procedure is provided. The procedure can be applied to downlink data transmission and includes the following steps.

[0074] Step 300: The current AP MLD receives the third downlink data transmitted by the DS.

[0075] In this embodiment of the present application, the DS may maintain a mapping relationship between the non-AP MLD and the current AP MLD, and a data path exists between the DS and the current AP MLD. When the DS receives third downlink data, the destination address of the third downlink data may be the address of the non-AP MLD. Based on the mapping relationship maintained between the non-AP MLD and the current AP MLD, the DS may determine that the non-AP MLD is associated with the current AP MLD. Thus, the DS forwards the third downlink data to the current AP MLD. Alternatively, the third downlink data is the downlink data to be transmitted by the current AP MLD. Therefore, step 300 is an embodiment and is not necessarily required.

[0076] Step 301: The current AP MLD encrypts the third downlink data using the first key to retrieve the first downlink data, where the first key is the key negotiated by the current AP MLD and the non-AP MLD.

[0077] For example, the current AP MLD may perform higher MAC layer processing on the third downlink data. In the process of higher MAC layer processing, the current AP MLD encrypts the third downlink data using a first key negotiated by the current AP MLD and non-AP MLD to obtain the first downlink data. In this case, the first downlink data can be called data encrypted using the first key, and the first key is a key negotiated by the current AP MLD and non-AP MLD. In the embodiment, the first key may be a pairwise transient key (PTK).

[0078] Step 302: The current AP MLD sends the first downlink data to the target AP MLD.

[0079] In the design, step 302 can be described as follows: The current AP MLD transparently transmits the first downlink data to the target AP MLD. For example, data transmission between the current AP MLD and the target AP MLD requires transfer by the DS. For example, the current AP MLD sends the first downlink data to the DS, and the DS transparently transmits the first downlink data to the target AP MLD.

[0080] Step 303: The target AP MLD performs lower MAC layer processing and physical layer processing on the first downlink data to obtain the second downlink data.

[0081] Step 304: The target AP MLD sends the second downlink data to the non-AP MLD.

[0082] For example, a second transmission link may be established between the target AP MLD and the non-AP MLD, and the target AP MLD may transmit second downlink data to the non-AP MLD via the second transmission link. The non-AP MLD receives the second downlink data from the target AP MLD. Alternatively, it can be described as follows: The non-AP MLD receives data from the current AP MLD via the target AP MLD.

[0083] For example, as shown in Figures 4A and 4B, the current AP MLD can receive third downlink data transmitted by the DS, and the DS can perform higher MAC layer processing on the third downlink data to obtain the first downlink data. Higher MAC layer processing includes, but is not limited to, at least one of sequence number SN assignment, packet number PN assignment, or downlink data encryption. In design, data input to the MAC layer may be called MSDU, and data obtained by the MAC layer through MAC layer processing may be called MPDU. Therefore, third downlink data can be called MSDU, first downlink data can be called MPDU, and downlink data encryption at the MAC layer can be called MPDU encryption. The current AP MLD transparently transmits the first downlink data to the target AP MLD via the DS. The target AP MLD performs lower MAC layer processing and physical layer processing on the first downlink data to obtain the second downlink data. As shown in Figures 4A and 4B, lower MAC layer processing includes, but is not limited to, MPDU header cyclic redundancy check (CRC) creation and / or A-MPDU aggregation. For example, in the MPDU header CRC creation process, the target AP MLD may add a CRC check bit to the header of the first downlink data. In the A-MPDU aggregation process, the target AP MLD may aggregate multiple first downlink data together. In the examples in Figures 4A and 4B, the interface between the current AP MLD's lower MAC layer and the physical layer, or the interface between the target AP MLD's lower MAC layer and the physical layer, may be called a physical layer service access point (SAP).The lower MAC of the target AP MLD transmits the data obtained from the lower MAC processing to the physical layer via the physical layer SAP, and the second downlink data is acquired by the physical layer processing. In the examples in Figures 4A and 4B, the specific processing processes at the physical layer are not described in detail.

[0084] Step 305: The non-AP MLD decrypts the second downlink data by using the first key.

[0085] In the scenario of this embodiment of the present application, a non-AP MLD includes a first transmission link and a second transmission link. The first transmission link is used for data transmission with the current AP MLD, and the second transmission link is used for data transmission with a target AP MLD. The first and second transmission links each have independent physical layers and independent lower MAC layers, and the two transmission links share a higher MAC layer. Specifically, upon receiving second downlink data from the target AP MLD, the non-AP MLD processes the second downlink data at its corresponding physical layer and lower MAC layer (for example, at the physical layer and lower MAC layer corresponding to the target AP MLD within the non-AP MLD) and delivers the processed data to the shared higher MAC layer. In the process of higher MAC layer processing, the non-AP MLD may decrypt the second downlink data by using a first key. As shown in Figures 4A and 4B, a non-AP MLD includes two protocol stacks: a physical layer and lower MAC layer protocol stack corresponding to the current AP MLD, and a physical layer and lower MAC layer protocol stack corresponding to the target AP MLD. The current AP MLD and the target AP MLD share the upper layer protocol stack. Upon receiving second downlink data transmitted by the target AP MLD, the non-AP MLD may process the second downlink data at the physical layer corresponding to the target AP MLD and transmit the second downlink data to the lower MAC layer corresponding to the target AP MLD via the physical layer SAP. Lower MAC layer processing includes, but is not limited to, at least one of the following: A-MPDU de-aggregation, MPDU header CRC validation, address 1 address filter, block ack scoreboard, etc.The non-AP MLD transmits data obtained from the lower MAC layer processing corresponding to the target AP MLD to the upper MAC layer. The upper MAC layer processing includes, but is not limited to, at least one of the following: block ack scoreboard, duplicate detection per SN, MPDU decryption, block ack buffering and reordering per SN, and replay detection per PN.

[0086] It should be noted that in this embodiment of the present application, the non-AP MLD has two transmission links: a first transmission link connected to the current AP MLD and a second transmission link connected to the target AP MLD. Before switching or before roaming ends, the mapping relationship between the non-AP MLD and the current AP MLD is stored in the DS. In the downlink transmission process, if downlink data is received whose destination address is the non-AP MLD, the DS transmits the downlink data to the current AP MLD based on the mapping relationship between the non-AP MLD and the current AP MLD. The specific processing performed by the current AP MLD includes, but is not limited to, the following: 1. The current AP MLD transmits all downlink data to the non-AP MLD via the first transmission link; 2. The current AP MLD transmits some of the downlink data to the non-AP MLD via the first transmission link and the remaining downlink data transparently to the non-AP MLD via the second transmission link; 3. The current AP MLD transparently transmits all downlink data to the target AP MLD via the DS, and the target AP MLD transmits all downlink data to the non-AP MLD via the second transmission link. The procedure in Figure 3 mainly describes the following: When downlink data is received from the DS, the current AP MLD transparently transmits the downlink data to the target AP MLD via the DS. The target AP MLD transmits the downlink data to the non-AP MLD. In possible embodiments, in the procedure in Figure 3, the current AP MLD may transparently transmit all downlink data received from the DS to the target AP MLD via the DS. Alternatively, in the procedure shown in Figure 3, the current AP MLD transmits a portion of the downlink data received from the DS to the non-AP MLD via the first transmission link. The current AP MLD then transparently transmits the remaining downlink data received from the DS to the target AP MLD via the DS.The target AP MLD transmits the remaining downlink data to the non-AP MLD via a second transmission link. Since the downlink data is divided into two parts, one of which is transmitted to the non-AP MLD via a different transmission link, the transmission speed of the downlink data is improved. Furthermore, in another scenario, the current AP MLD duplicates the downlink data received from the DS. One duplicate is transmitted to the non-AP MLD via the first transmission link. The other duplicate is transparently transmitted to the target AP MLD via the DS. The target AP MLD then transmits the downlink data to the non-AP MLD, etc., via the second transmission link. In this way, the reliability of downlink data transmission can be improved. Additionally, the current AP MLD may transmit some or all of the downlink data it intends to send to the target AP MLD, which then transmits the received downlink data to the non-AP MLD. In this embodiment of the present application, the source of the downlink data for the current AP MLD is not limited, and the focus is on the processes by which the current AP MLD and the target AP MLD process the downlink data when the current AP MLD transmits the downlink data to the target AP MLD.

[0087] [Uplink Data Transmission]

[0088] In the design, for uplink data transmission, the non-AP MLD establishes two transmission links: a first transmission link with the current AP MLD and a second transmission link with the target AP MLD. Before switching or before roaming ends, the mapping relationship between the current AP MLD and the non-AP MLD is stored on the DS. For the DS to process the uplink data correctly, the uplink data must be delivered to the current AP MLD, which then delivers the uplink data to the DS. The non-AP MLD delivers the uplink data to the current AP MLD in several ways, including but not limited to the following:

[0089] 1. The non-AP MLD delivers uplink data to the current AP MLD via the first transmission link.

[0090] 2. The non-AP MLD delivers a portion of the uplink data to the current AP MLD. The non-AP MLD delivers the remaining uplink data to the target AP MLD. The target AP MLD transparently transmits the remaining uplink data to the current AP MLD via the DS. The uplink data transmission rate is improved because the uplink data is divided into two copies, which are transmitted to the current AP MLD via different links.

[0091] 3. The non-AP MLD distributes all uplink data to the target AP MLD. The target AP MLD transparently transmits all uplink data to the current AP MLD, etc., via DS.

[0092] 4. A non-AP MLD may generate two copies of the uplink data. One copy is sent directly to the current AP MLD via the first transmission link, and the other copy is sent to the target AP MLD via the second transmission link. The target AP MLD transparently transmits the uplink data to the current AP MLD via the DS. Since the same uplink data is transmitted via two transmission links, the transmission reliability of the uplink data is improved.

[0093] Methods 2, 3, and 4 all relate to the following process: a non-AP MLD transmits uplink data to a target AP MLD, and the target AP MLD transparently transmits the uplink data to the current AP MLD via the DS. In possible embodiments, methods 1 through 4 are illustrative examples only and are not intended to limit the uplink data transmission scenarios in this application.

[0094] In the uplink data transmission process provided in this embodiment of the present application, when transmitting uplink data to a target AP MLD, the non-AP MLD encrypts the uplink data by using a first key negotiated by the non-AP MLD and the current AP MLD. A procedure is provided as shown in Figure 5. The procedure can be applied to uplink data transmission and includes the following steps:

[0095] Step 500: The non-AP MLD determines the first uplink data by encrypting the uplink data to be transmitted using the first key, where the first key is a key negotiated by the non-AP MLD and the current AP MLD.

[0096] In the design, the non-AP MLD sequentially processes the uplink data to be transmitted, including the processing of the shared upper MAC layer, the processing of a dedicated lower MAC layer, and the processing of a dedicated physical layer. Upper MAC layer processing includes, at a minimum, encrypting the uplink data to be transmitted by using a first key negotiated by the non-AP MLD and the current AP MLD. As shown in Figures 6A and 6B, upper MAC layer processing by the non-AP MLD includes, but is not limited to, at least one of the following: sequence number SN assignment, packet number PN assignment, and MPDU encryption. In MPDU encryption, the non-AP MLD encrypts the uplink data by using a first key negotiated with the current AP MLD. Furthermore, the non-AP MLD includes two transmission links, each transmission link exclusively occupying the lower MAC layer and physical layer. In other words, the first and second transmission links correspond to independent lower MAC layers and independent physical layers, respectively. In this embodiment of the present application, the non-AP MLD can process uplink data at the lower MAC layer and physical layer corresponding to the second transmission link corresponding to the target AP MLD. For example, as shown in Figures 6A and 6B, the lower MAC layer processing corresponding to the target AP MLD includes, but is not limited to, MPDU header CRC creation and A-MPDU aggregation. In Figures 6A and 6B, the lower MAC layer of the target AP MLD delivers uplink data to the physical layer of the target AP MLD via the physical layer SAP, and then performs physical layer processing on the uplink data. After physical layer processing, the uplink data is transmitted to the target AP MLD via the second transmission link.

[0097] Step 501: The non-AP MLD sends the first uplink data to the target AP MLD.

[0098] Step 502: The target AP MLD performs physical layer processing and lower MAC layer processing on the first uplink data to determine the second uplink data.

[0099] As shown in Figures 6A and 6B, the lower MAC layer processing by the target AP MLD includes, but is not limited to, at least one of the following: A-MPDU de-aggregation, MPDU header CRC validation, address-1 address filtering, and block acknowledgment scoreboarding.

[0100] Step 503: The target AP MLD sends the second uplink data to the current AP MLD.

[0101] Accordingly, the current AP MLD receives second uplink data from the target AP MLD. Alternatively, it can be described as follows: The current AP MLD receives uplink data from the non-AP MLD via the target AP MLD. Alternatively, it can be described as follows: The non-AP MLD sends second uplink data to the current AP MLD via the target AP MLD.

[0102] Step 504: The current AP MLD performs higher MAC layer processing on the second uplink data, decrypts the second uplink data using the first key, and determines the third uplink data.

[0103] As shown in Figures 6A and 6B, current AP MLD upper MAC layer processing includes, but is not limited to, at least one of the following: block ack scoreboard, duplicate detection per SN, MPDU decryption, block ack buffering and reordering per SN, and replay detection per PN.

[0104] From steps 502 to 504, it can be seen that when the target AP MLD receives uplink data from the non-AP MLD, the target AP MLD performs physical layer processing and lower MAC layer processing on the received uplink data, bypassing the higher MAC processing performed by the target AP MLD, and transmits the uplink data obtained from the lower MAC layer processing to the current AP MLD. After receiving the uplink data, the current AP MLD performs higher MAC layer processing on the uplink data.

[0105] Step 505: The current AP MLD sends the third uplink data to the DS.

[0106] In the design, the current AP MLD may transmit the third uplink data to the DS, which then processes or applies the third uplink data. Alternatively, the third uplink data may be transmitted to the current AP MLD, which can then process or apply the third uplink data directly. In this case, the third uplink data does not need to be reported to the DS. In this case, step 505 does not need to be performed. Therefore, step 505 is optional.

[0107] This embodiment of the present application further provides a procedure used to establish a second transmission link between a non-AP MLD and a target AP MLD. For example, a first transmission link is established between the non-AP MLD and the current AP MLD. In this embodiment, the first transmission link can be considered as a data connection between the non-AP MLD and the current AP MLD. A data path exists between the current AP MLD and the DS, and the mapping relationship between the non-AP MLD and the current AP MLD is stored in the DS. The current AP MLD, by measurement, knows that the link quality of the first transmission link between the non-AP MLD and the current AP MLD has deteriorated, for example, that the link quality of the first transmission link is below a threshold. In this case, the current AP MLD may enable the non-AP MLD to perform beacon measurements. Based on the beacon measurement results reported by the non-AP MLD, the current AP MLD recommends to the non-AP MLD which AP MLD the non-AP MLD should switch to. The non-AP MLD selects one AP MLD from the recommended AP MLDs, and that AP MLD becomes the target AP MLD. In the embodiment, the non-AP MLD reports the target AP MLD selected by the non-AP MLD to the current AP MLD. In the embodiment, the current AP MLD may send a seventh request to the non-AP MLD. The seventh request further includes second instruction information, which instructs the non-AP MLD to reserve BS session information and / or context information and to buffer data not yet sent by the non-AP MLD. Upon receiving the second instruction information, the non-AP MLD may reserve BS session information and / or context information in subsequent provisional association processes. In the embodiment, the non-AP MLD may send a seventh response to the current AP MLD. The seventh response is a response to the seventh request.In this embodiment, the seventh request may be a BSS transition management (BTM) request frame, and the seventh response may be a BTM response frame.

[0108] [Provisional association]

[0109] A non-AP MLD can establish a provisional association with a target AP MLD by using an affiliated STA. In the provisional association process, the non-AP MLD can establish a second transmission link with the target AP MLD. Furthermore, transmission capability parameters of the non-AP MLD and target AP MLD (e.g., transmission bandwidth and maximum number of streams for both the non-AP MLD and target AP MLD), key information of the non-AP MLD and target AP MLD (e.g., PTK, group temporal key (GTK), integrity group temporal key (IGTK), and beacon integrity grouper temporal key (BIGTK)), and resource allocation information of the non-AP MLD and target AP MLD (e.g., establishment of BA sessions and restricted target wakeup time (r-TWT)) can be negotiated between the non-AP MLD and target AP MLD.

[0110] In the design, a non-AP MLD may send a first request to a target AP MLD. The first request is used to request the establishment of a second transmission link between the non-AP MLD and the target AP MLD. The target AP MLD sends a first response to the non-AP MLD. The first response is a response to the first request. For example, a non-AP MLD may send a first request to a target AP MLD. The first request is used to request the establishment of a second transmission link. Upon receiving the first request, the target AP MLD may send a first response to the non-AP. The first response indicates that the target AP MLD has agreed to establish the second transmission link and also indicates at least one of the following: transmission capability parameters, key information, resource allocation information, etc., for both the target AP MLD and the non-AP MLD. The target AP MLD sends a first response to the non-AP MLD. The first response may include at least one of the following: transmission capability parameters of the target AP MLD and non-AP MLD negotiated by the target AP MLD and non-AP MLD; key information; resource allocation information of the target AP MLD and non-AP MLD; and so on.

[0111] In this embodiment, the first request may be a reassociation request frame, which carries provisional association instruction information. The association request frame, which carries provisional association instruction information, is used by the non-AP MLD to request a provisional association with the target AP MLD. The first response may be a reassociation response frame, which can carry provisional association instruction information, and the reassociation response frame, which carries provisional association instruction information, is used to perform a provisional association between the non-AP MLD and the target AP MLD. In the provisional association process, the non-AP MLD and the target AP MLD may establish a second transmission link and negotiate various parameters.

[0112] In another embodiment, the first request may be a newly defined action frame, carrying the same content as a reassociation request frame, and the first request is used by the non-AP MLD to request a provisional association with the target AP MLD. The first response may be a newly defined action frame, carrying the same content as a reassociation response frame, and the first response is used to perform a provisional association between the non-AP MLD and the target AP MLD. In the provisional association process, the non-AP MLD and the target AP MLD may establish a second transmission link and negotiate various parameters.

[0113] During the provisional association process, the target AP MLD does not refresh the mapping relationship between the non-AP MLD and the current AP MLD stored on the DS side. Before sending the first request (e.g., a reassociation request frame), the non-AP MLD does not delete the first key negotiated with the current AP MLD, nor does it clear the transmit buffer, receive buffer, etc. The non-AP MLD still maintains the first transmission link with the current AP MLD, and uplink data and / or downlink data can still be transmitted between the non-AP MLD and the current AP MLD via the first transmission link.

[0114] In the embodiment, the first request may include instruction information for establishing dual-link transmission of a non-AP MLD, where the dual links include a first transmission link between the non-AP MLD and the current AP MLD, a second transmission link between the non-AP MLD and the target AP MLD, and so on. After the target AP MLD receives the instruction information and successfully establishes the second transmission link, the target AP MLD initiates negotiation for dual-link transmission to the current AP MLD in order to enable dual-link transmission.

[0115] [Dual-link transmission]

[0116] In the dual-link roaming process, data needs to be transmitted between the current AP MLD and the target AP MLD. Therefore, if the target AP MLD receives instructions from the non-AP MLD to enable dual-link transmission based on the first request, it may send a second request to the current AP MLD. The second request is used to request that the non-AP MLD enable dual-link transmission. In dual-link downlink transmission, the current AP MLD can transparently transmit the encrypted downlink data from the non-AP MLD to the target AP MLD, which then transmits the downlink data to the non-AP MLD. In dual-link uplink transmission, the target AP MLD can transparently transmit the uplink data received from the non-AP MLD to the current AP MLD, which decrypts the uplink data and transmits the decrypted uplink data to a DS or similar device. For specific processes, please refer to the [Uplink Data Transmission] and [Downlink Data Transmission] sections described above. In the example, the current AP MLD may send a second response to the target AP MLD. The second response is a response to the second request. For example, the second response may include instructional information indicating whether the current AP MLD has agreed to enable dual-link transmission.

[0117] In design, dual-link transmission in the roaming process can be described as roaming transmission based on a dual active protocol stack (DAPS). DAPS-based roaming transmission can mean that a non-AP MLD performing the same transmission and reception on multiple links can simultaneously perform uplink and / or downlink transmission with the current AP MLD and the target AP MLD during roaming. For example, the second request may be a DAPS enable request, and the second response may be a DAPS enable response.

[0118] In the design, the target AP MLD may send to the current AP MLD the maximum MAC layer MPDU length supported by the target AP MLD, the maximum number of aggregated MAC layer MSDUs allowed by the target AP MLD, etc. In this case, the data sent from the current AP MLD to the target AP MLD must satisfy the aforementioned requirements. In the embodiment, the second request may include the maximum MAC layer MPDU length supported by the target AP MLD, the maximum number of aggregated MAC layer MSDUs allowed by the target AP MLD, etc. In the embodiment, the target AP MLD may further send to the current AP MLD the MLD address corresponding to the non-AP MLD, etc.

[0119] Similarly, the current AP MLD may transmit to the target AP MLD the maximum MAC layer MPDU length supported by the current AP MLD, the maximum number of aggregated MAC layer MSDUs allowed by the current AP MLD, etc. In this case, the data transmitted from the target AP MLD to the current AP MLD must satisfy the aforementioned requirements. In this embodiment of the present application, the method by which the current AP MLD transmits to the target AP MLD the maximum MAC layer MPDU length supported by the current AP MLD, the maximum number of aggregated MAC layer MSDUs allowed by the current AP MLD, etc., is not limited.

[0120] In possible embodiments, data transmission between the target AP MLD and the current AP MLD may be transferred via the DS. In this embodiment of the Application, it is not limited whether the DS performs any relevant processing and / or operations on the data in the data transfer process. If the DS does not perform any relevant operations or processing on the data, it may be referred to as transparent transmission by the DS. In design, the current AP MLD may encapsulate the data in a special frame or message and transparently transmit the frame or message to the target AP MLD via the DS. In possible embodiments, the term "transparent transmission" in the relevant descriptions in this embodiment of the Application may be replaced by relevant descriptions such as transmission or transfer. If the DS performs corresponding operations and / or processing on the received data in the data transfer process, this also falls within the scope of protection of this embodiment of the Application. Alternatively, the data may be transmitted directly between the target AP MLD and the current AP MLD. This is not limited.

[0121] [Data path switching]

[0122] A non-AP MLD may trigger a data path switch. For example, the transmission path of the non-AP MLD is switched from the current AP MLD to the target AP MLD. In a possible embodiment, after the data path switch, the non-AP MLD encrypts / decrypts uplink data and / or downlink data, etc., by using a second key negotiated with the target AP MLD. In the embodiment, the second key may be a PTK.

[0123] In this embodiment of the present application, the conditions for triggering a data path switch by a non-AP MLD are not limited. For example, a non-AP MLD may trigger a data path switch if a first condition is met. This first condition includes, but is not limited to, the link quality of the target AP MLD's optimal link being higher than the link quality of the current AP MLD's optimal link.

[0124] During roaming, the non-AP MLD simultaneously transmits data through both the first and second transmission links. Once roaming is complete, the non-AP MLD may perform a data path switch. In this description, during the data path switch process, the non-AP MLD disconnects the first transmission link and fully utilizes the second transmission link for data transmission. Alternatively, in other descriptions, as seen in the aforementioned example in Figure 2, in dual-link transmission, the non-AP MLD establishes transmission links with the current AP MLD and the target AP MLD, respectively, by using different STA entities. For example, as shown in Figure 2, during the roaming process, STA1 of the non-AP STA establishes the first transmission link with the current AP MLD, and STA2 of the non-AP MLD establishes the second transmission link with the target AP MLD. During the data path switch process, STA1 disconnects the first transmission link with the current AP MLD, and STA1 establishes a different transmission link with the target AP MLD.

[0125] In the design, during the process in which a non-AP MLD triggers a path switch, the non-AP MLD may send a third request to the target AP MLD. The third request is used to request that the non-AP MLD trigger a path switch (for example, the switch may be a data path switch). In the embodiment, the target AP MLD may send a third response to the non-AP MLD. The third response may be a response to the third request. For example, the third response may contain instructional information indicating whether to agree to the path switch. If the target AP MLD agrees to the non-AP MLD's path switch, the target AP MLD may send a fourth request to the DS. The fourth request is used to request the DS to update the stored mapping relationship between the non-AP MLD and the current AP MLD to the mapping relationship between the non-AP MLD and the target AP MLD. In the embodiment, the DS may send a fourth response to the target AP MLD. The fourth response may be a response to the fourth request. In the embodiment, the fourth response may include instructional information indicating whether the DS agrees to update the mapping relationships. Alternatively, the target AP MLD may send an uplink data packet to the DS via MAC SAP. Based on the information about the non-AP MLD that may be carried in the uplink data packet, the DS automatically updates the mapping relationships and other information it holds.

[0126] In this embodiment, the third request is an STA-to-AP mapping request frame, and the third response is an STA-to-AP mapping response. The fourth request may be an updated or newly added DS-STA notify request, and the fourth response may be a DS-STA notify response.

[0127] Furthermore, after the target AP MLD receives the third request and before the target AP MLD sends the fourth request to the DS, the method further includes the target AP MLD sending a context transfer request to the current AP MLD and the target AP MLD receiving a context transfer response sent by the current AP MLD. The context transfer response contains context information for the non-AP MLD.

[0128] In the embodiment, the context forwarding response further includes at least one of the following: a block acknowledgment protocol for a traffic identifier (TID), the window start position of the transmit buffer for the TID, the window size of the transmit buffer for the TID, the window start position of the uplink receive end scoreboard, the window size of the uplink receive end scoreboard, the window start position of the receive sort buffer, the window size of the receive sort buffer, the currently received maximum packet number PN value, or the uplink replay counter.

[0129] In the design, the target AP MLD receives a third request from the non-AP MLD. The third request is used to request a path switch. The target AP MLD sends a context transfer request to the current AP MLD. The target AP MLD receives a context transfer response from the current AP MLD. The target AP MLD waits for a certain period of time, and then sends a fourth request to the DS to refresh the mapping relationships stored on the DS side. In this way, it is ensured that uplink delivery is not interrupted. The reason is as follows: Uplink data is delivered to the DS via the current AP MLD before the mapping relationships stored on the DS side are updated. At the moment when the transmission path of the non-AP MLD switches from the first transmission path to the second transmission path, i.e., when the target AP MLD receives the context transfer response from the current AP MLD, it is possible that the processing of uplink data delivered to the DS by the current AP MLD is not yet complete. Therefore, in this embodiment of the present application, upon receiving the context transfer response from the current AP MLD, the target AP MLD waits for a certain period of time. In this case, once the DS has finished processing the uplink data of the current AP MLD, a fourth request is sent to the DS to refresh the mapping relationship. Alternatively, before sending a context forwarding response, the current AP MLD must ensure that all of its uplink data is successfully delivered to the DS. For example, in the embodiment, after the current AP MLD sends a sixth request to the DS, which is used to remove the mapping relationship between the non-AP MLD and the current AP MLD, the current AP MLD sends a context forwarding response to the target AP MLD. See the description below for the sixth request.

[0130] In the embodiment, if the non-AP MLD decides to trigger a path switch, the non-AP MLD may further send a fifth request to the current AP MLD. The current AP MLD receives the fifth request sent by the non-AP MLD. The fifth request is used to request that the association between the non-AP MLD and the current AP MLD be severed. Upon receiving the fifth request, the current AP MLD may disconnect the first transmission link with the non-AP MLD. In the embodiment, the fifth request includes first instruction information, which instructs the current AP MLD to reserve the non-AP MLD's BA information and / or context information and to buffer data not sent by the non-AP MLD. After the current AP MLD receives the fifth request, it sends a sixth request to the DS. The sixth request is used to request that the mapping relationship between the non-AP MLD and the current AP MLD, which is held in the DS, be removed. Upon receiving the sixth request, the DS may delete the mapping relationship between the non-AP MLD and the current AP MLD that is being held by the DS. In the embodiment, the current AP MLD may actively trigger the non-AP MLD to perform a BSS transition. For example, the current AP MLD actively triggers the non-AP MLD to switch to a target AP MLD. In this case, the current AP MLD may send a fifth request to the non-AP MLD. The fifth request is used to break the association between the current AP MLD and the non-AP MLD.

[0131] In this embodiment, the fifth request may be a disassociation frame, and the sixth request may be a DS-STA notification request for deletion.

[0132] In the design, a non-AP MLD does not have to send a fifth request to the current AP MLD. In this case, when the current AP MLD receives a context transfer request from the target AP MLD and does not receive a fifth request sent by the non-AP MLD, the current AP MLD may stop delivering uplink data to the DS and send a sixth request to the DS. The sixth request is used to request that the DS remove the mapping relationship between the non-AP MLD and the current AP MLD that is being held. The current AP MLD then sends a context transfer response to the target AP MLD.

[0133] In addition, as described above, the target AP MLD may send a fourth request to the DS. The fourth request is used to request the DS to update the stored mapping relationship between the non-AP MLD and the current AP MLD to the mapping relationship between the non-AP MLD and the target AP MLD. In addition, as described above, the current AP MLD may send a sixth request to the DS. The sixth request is used to request the deletion of the mapping relationship between the non-AP MLD and the current AP MLD that is held in the DS. In the design, the DS first performs the following actions: it receives the sixth request and deletes the mapping relationships between the non-AP MLD and the current AP MLD and the current AP MLD that are held in the DS. Next, the DS receives the fourth request. The fourth request is used to add a new mapping relationship between the non-AP MLD and the target AP MLD to the DS's storage. In other words, updating the mapping relationship in the fourth request may also instruct the DS to add a new mapping relationship between the non-AP MLD and the target AP MLD. Alternatively, upon receiving the fourth request, the DS directly updates the mapping relationship stored in the DS. For example, the mapping relationship between the non-AP MLD and the current AP MLD, which is maintained in the DS, is replaced with the mapping relationship between the non-AP MLD and the target AP MLD. In this case, the current AP MLD no longer needs to send a sixth request to the AP MLD that is used to delete the mapping relationship.

[0134] On the DS side, after receiving the fourth request from the target AP MLD, the DS may switch data paths. For example, the DS may delete the data path between the non-AP MLD and the current AP MLD, and then add a data path between the non-AP MLD and the target AP MLD. After the current AP MLD successfully sends a context transfer response, the current AP MLD may release the context of the non-AP MLD.

[0135] In this embodiment of the present application, the current AP MLD is further required to transmit downlink data and / or uplink data to the target AP MLD that satisfies the following conditions. For example, in the design, upon receiving a context transfer request from the target AP MLD, the current AP MLD may transmit the downlink data and / or uplink data described below to the target AP MLD. The downlink data and / or uplink data described below may be carried in the context transfer response. Alternatively, before or after the current AP MLD transmits the context transfer response to the target AP MLD, the current AP MLD may transmit the uplink data and / or downlink data, etc., described below to the target AP MLD. This is not limited.

[0136] For example, for downlink data transmission, the current AP MLD needs to transfer the (unencrypted) downlink data to the target AP MLD and carry the end identifier using the last part of the downlink data. In this embodiment, the downlink data may be an MSDU or MPDU. In the case of downlink data in MPDU format, the more data field in the MPDU header may be reused. For example, when the MPDU is the last part of the downlink data, the more data field is set to a first value, or when the MPDU is not the last part of the downlink data, the more data field is set to a second value. In this embodiment, the first value may be 0 and the second value may be 1. Upon receiving the downlink data transferred by the current AP MLD, the target AP MLD encrypts the downlink data using a second key and then sends the downlink data to the non-AP MLD.

[0137] For example, in the case of uplink data transmission, the current AP MLD may transfer the uplink data (e.g., decrypted MSDU or MPDU) obtained by upper MAC layer processing in the receive buffer to the target AP MLD, store the uplink data in the receive sort buffer, and then the target AP MLD sequentially transmits the received complete continuous uplink data to the DS.

[0138] In the design, during switching, the non-AP MLD disconnects the old link with the current AP MLD and then establishes a new link with the target AP MLD. Before the non-AP MLD establishes the new link with the target AP MLD, the non-AP clears its transmit and receive buffers, resulting in packet loss. The receive buffer is used to store discontinuous data received by the non-AP MLD, and the transmit buffer is used to store data not transmitted by the non-AP MLD, or data transmitted by the non-AP but not acknowledged by the receiving end. In the solution of this embodiment of the present application, the non-AP MLD first establishes a second transmission link with the target AP MLD. During this period, the non-AP MLD and the current AP MLD do not clear their transmit or receive buffers, and the non-AP MLD and the current AP MLD continue to perform data transmission, thus avoiding packet loss. Next, at some point, the non-AP MLD disconnects the first transmission link with the current AP MLD and transfers the transmission session or block acknowledgment (BA) session to the target AP MLD. During the switching process, the non-AP MLD can simultaneously transmit data with the current AP MLD and the target AP MLD based on its multilink capability, thereby reducing the list of rate degradations during the switching process.

[0139] [Embodiment 1]

[0140] In this embodiment of the present application, the second transmission link is established directly between the non-AP MLD and the target AP. One or both of the aforementioned first and third requests are transmitted via the air interface between the non-AP MLD and the target AP MLD. A procedure is provided as shown in Figure 7a. Note that a first transmission link exists between the non-AP MLD and the current AP MLD before the procedure in Figure 7 is performed. For example, a data connection exists between the non-AP MLD and the current AP MLD and the current AP MLD. A data path exists between the current AP MLD and the DS, and the mapping relationship between the non-AP MLD and the current AP MLD is stored in the DS. As shown in Figure 7a, the procedure includes the following steps.

[0141] Step 701: The current AP MLD notices that the link quality of the non-AP MLD is degraded, and sends a beacon measurement request to the non-AP MLD.

[0142] Step 702: The non-AP MLD performs beacon measurements and feeds the beacon measurement report back to the current AP MLD.

[0143] Step 703: The current AP MLD recommends that the non-AP MLD switch to a nearby AP MLD based on the beacon measurement report. For example, the current AP MLD sends a BTM request frame to the non-AP MLD. The BTM request frame contains information about at least one AP MLD recommended by the current AP MLD. The non-AP MLD selects one AP MLD from the at least one recommended AP MLD as the target AP MLD.

[0144] In this embodiment, the BTM request frame includes a second instruction information which reserves the non-AP MLD's BA information and / or context information and instructs the non-AP MLD to buffer data that has not been transmitted by the non-AP MLD. Upon receiving the second instruction information, the non-AP MLD may enable dual-link roaming based on DAPS.

[0145] In the embodiment, before the current AP MLD sends a BTM request frame to the non-AP MLD, the method may further include the non-AP MLD sending a BTM query frame to the current AP MLD. After receiving the BTM query frame, the current AP MLD sends a BTM request frame to the current AP MLD.

[0146] Step 704: The non-AP MLD sends a BTM response frame to the current AP MLD, which includes the target AP MLD selected by the non-AP MLD.

[0147] Step 705: The non-AP MLD performs a provisional association with the target AP MLD. The provisional association process may include: establishing a second transmission link between the target AP MLD and the non-AP MLD, e.g., the bandwidth and maximum number of supported streams of the second transmission link; establishing a BA session; and negotiating a key, which in turn includes a second key for communication between the target AP MLD and the non-AP MLD.

[0148] In the embodiment, the non-AP MLD and the target AP MLD may perform a provisional association by using a reassociation request frame and a reassociation response frame. For details on the reassociation request frame and the reassociation response frame, please refer to the above description of the first request and first response. In possible embodiments, during the provisional association process, the mapping relationship between the non-AP MLD and the AP MLD, which is maintained on the DS side, is not refreshed. In this case, the mapping relationship between the non-AP MLD and the current AP MLD is maintained on the DS side. In this case, when the non-AP MLD receives downlink data, the DS delivers the downlink data to the current AP MLD.

[0149] Step 706: After the non-AP MLD and the target AP MLD have completed the provisional association, the target AP MLD and the current AP MLD may enable DAPS-based roaming by exchanging DAPS enable requests and DAPS enable responses.

[0150] For details regarding the DAPS enable request and DAPS enable response, please refer to the descriptions above for the second request and second response.

[0151] Step 707: The non-AP MLD triggers a path switch. The non-AP MLD sends an STA-AP mapping request frame to the target AP MLD. The STA-AP mapping request frame may be used to request the target AP MLD to perform a path switch. See the third request above for details on the STA-AP mapping request frame.

[0152] Step 708: The target AP MLD sends a context transfer request to the current AP MLD.

[0153] Step 709: The current AP MLD sends a context forwarding response to the target AP MLD. Refer to the previous description for the contents carried in the context forwarding response.

[0154] Step 7010: The target AP MLD sends a DS-STA notification request to the DS.

[0155] Upon receiving a DS-STA notify request, the DS may update its stored mapping relationship from the mapping relationship between the non-AP MLD and the current AP MLD to the mapping relationship between the non-AP MLD and the target AP MLD. The DS then disconnects the data path with the current AP MLD and establishes a data path with the target AP MLD. For details on DS-STA notify requests, please refer to the description above in Request 4.

[0156] Step 7011: The current AP MLD removes the context of the non-AP MLD.

[0157] After step 7011, the transmission path for the non-AP MLD is switched from the first transmission path to the second transmission path.

[0158] The non-AP MLD and target AP MLD may encrypt / decrypt uplink data and / or downlink data by using a negotiated second key.

[0159] In the embodiment, if the non-AP MLD decides to trigger a path switch in step 707, the method further includes the non-AP MLD sending an isolation frame to the current AP MLD. See Request 5 above for details on the isolation frame. The current AP MLD may send a DS-STA notify request for deletion to the DS. The DS deletes any mapping relationships between the non-AP MLD and the current AP MLD that are held in the DS.

[0160] In this embodiment of the present application, the transmission between the current AP MLD and the target AP MLD is a transparent transmission performed via DS. In this embodiment of the present application, the transmission between the current AP MLD and the target AP MLD includes, but is not limited to, DAPS enable requests, DAPS enable responses, context transfer requests, context transfer responses, etc. Furthermore, uplink data and / or downlink data may be further transmitted between the current AP MLD and the target AP MLD. For details, see the preceding descriptions of [Uplink Data Transmission] and [Downlink Data Transmission].

[0161] In the design, the following frame formats may be used for information and / or data transmitted between the AP MLD and the target AP MLD. As shown in Figure 7b, the frame format includes at least one of the following fields: Destination MAC address: A MAC address that can carry 48 bits; Source MAC address: A MAC address that can carry 48 bits; Length field; A logical link control (LLC) field containing the destination service access point (DSAP) address (the field is fixed to AA), the destination service access point (SSAP) address (the field is fixed to AA), and a control field (the field is fixed to 0x03); A subnetwork access protocol (SNAP) field that includes an organizationally unique identifier field and an Ethernet type field; Payload type field: The field can be set to one or more preset values ​​based on different payloads; and Payload field: For example, the payload field may carry a DAPS enable request, a DAPS enable response, a context transfer request, a context transfer response, or uplink / downlink data that needs to be transparently transmitted. The payload field may carry an MPDU that conforms to the tunneling 802.11 protocol, etc.

[0162] When uplink / downlink data is transmitted transparently between the current AP MLD and the target AP MLD, the information carried in the payload field refers to the configuration of additional authentication data (AAD) of the cipher-block chaining message authentication code protocol (CCMP), and includes the CCMP header and the encrypted frame body. In the design, as shown in Figure 7c, the payload field includes at least one of the following: frame control, address 1, address 2, address 3, sequence control, quality of service (QoS) control, encryption protocol header (CCMP header), and frame body.

[0163] In the embodiment, the payload field may further include at least one of the following: a retry field, a power management field, a data field, a high throughput control (HTC) field, a QoS field excluding the TID field, etc. Furthermore, if the payload field carries the aforementioned fields, the specific values ​​of the aforementioned fields may be set to null.

[0164] In the switching or roaming process of a non-AP MLD, the non-AP MLD and the current AP MLD establish a dual link between the current AP MLD and the target AP MLD based on their multilink capabilities in order to perform data transmission using both the current AP MLD and the target AP MLD, thereby improving the transmission rate and transmission reliability during roaming. Furthermore, in the roaming process, the non-AP MLD does not disconnect the first transmission link with the current AP MLD and does not clear the non-AP MLD's transmit and receive buffers, thus reducing the probability of packet loss and / or interruption during roaming.

[0165] [Embodiment 2]

[0166] In this embodiment of the present application, a second transmission link between the non-AP MLD and the target AP is established via the current AP MLD and DS. One or both of the aforementioned first and third requests are transmitted via the current AP MLD and DS. For example, the non-AP MLD may send one or both of the first and third requests to the current AP MLD, and the current AP MLD sends the first and / or third requests to the target AP MLD via the transparent transmission of the DS.

[0167] Regarding non-AP MLDs, there is also an important device type: the enhanced multi-link single radio (EMLSR) non-AP MLD. In design, an EMLSR non-AP MLD means that it has multiple receiving radio frequency chains and can monitor multiple links simultaneously. When an initial control frame transmitted by an AP MLD is received, the radio frequency chain of another link in the EMLSR link set is switched to the corresponding link that received the initial control frame, increasing the number of streams to receive / transmit. In other words, at any given moment, an EMLS non-AP MLD can select only one link to receive / transmit data. Compared to a multi-radio non-AP MLD, an eMLSR non-AP MLD has only one fully functional transceiver, with the remaining transceivers being less expensive machines with limited functionality (as they can only receive specific initial control frames). Therefore, eMLSR non-AP MLDs are significantly cheaper than multi-radio non-AP MLDs, but their performance is significantly lower. An EMLSR non-AP MLD can only receive / transmit data on one link. If an EMLSR non-AP MLD makes a provisional association with a target AP MLD based on the solution of Embodiment 1, the EMLSR non-AP MLD needs to jump to the corresponding channel of the target AP MLD in order to perform the provisional association operation. This causes an interruption in data transmission with the current AP MLD and has a serious impact on the roaming performance of the EMLSR non-AP MLD. Therefore, Embodiment 2 provides a solution to further improve the roaming performance of non-AP MLDs, and in particular to improve the roaming performance of non-AP MLDs and EMLSR non-AP MLDs with a single radio link.

[0168] As shown in Figure 8, a procedure is provided. Before the procedure in Figure 8 is performed, a first transmission link is established between the non-AP MLD and the current AP MLD, and this first transmission link is also called the data connection between the current AP MLD and the non-AP MLD. A data path exists between the DS and the current AP MLD, and the mapping relationship between the non-AP MLD and the current AP MLD is stored in the DS. As shown in Figure 8, the procedure includes the following steps.

[0169] Step 801: The current AP MLD notices that the link quality of the non-AP MLD is degraded, and sends a beacon measurement request to the non-AP MLD.

[0170] Step 802: The non-AP MLD performs beacon measurements and feeds the beacon measurement report back to the current AP MLD.

[0171] Step 803: The current AP MLD recommends that the non-AP MLD switch to a nearby AP MLD based on the beacon measurement report. For example, the current AP MLD sends a BTM request frame to the non-AP MLD. The BTM request frame contains information about at least one AP MLD recommended by the current AP MLD. The non-AP MLD selects one AP MLD from the at least one recommended AP MLD as the target AP MLD.

[0172] In the embodiment, before the current AP MLD sends a BTM request frame to the non-AP MLD, the method may further include the non-AP MLD sending a BTM query frame to the current AP MLD. After receiving the BTM query frame, the current AP MLD sends a BTM request frame to the current AP MLD.

[0173] Step 804: The non-AP MLD sends a BTM response frame to the current AP MLD, which includes the target AP MLD selected by the non-AP MLD.

[0174] Step 805: The non-AP MLD and the target AP MLD perform a tentative association, which may be an over-the-DS tentative reassociation.

[0175] To ensure that data transmission with the current AP MLD is not interrupted when a non-AP MLD and a target AP MLD perform a provisional association operation, an over-the-DS (DS) provisional association operation method is defined. In other words, a non-AP MLD can perform a provisional association operation with the target AP MLD via the current AP MLD.

[0176] For example, a non-AP MLD may send a first request to the current AP MLD. The first request is used to request the establishment of a second transmission link between the non-AP MLD and the target AP MLD. After receiving the first request, the current AP MLD transparently transmits the first request to the target AP MLD via DS. Based on the first request, the target AP MLD may establish a second transmission link between the target AP MLD and the non-AP MLD. The second transmission link may be an air interface between the non-AP MLD and the target AP MLD. In this embodiment, the target AP MLD may send a first response to the current AP MLD via transparent transmission of DS. The current AP MLD sends the first response to the non-AP MLD. In this embodiment, the first request and the first response may be a fast BSS transition (FT) probe request and a probe response, respectively.

[0177] In the embodiment, when the first request is transmitted via the current AP MLD and DS, the first request does not include operating channel information (OCI), thus reducing the signaling overhead of the first request.

[0178] The non-AP MLD sends an eighth request to the current AP MLD, and the current AP MLD transparently transmits the eighth request to the target AP MLD via the DS. The eighth request is used to request communication parameters from the target AP MLD. The target AP MLD sends an eighth response to the current AP MLD via the DS, and the current AP MLD sends the eighth response to the non-AP MLD. The eighth response includes a second key negotiated by the non-AP MLD and the target AP MLD. In this embodiment, the eighth request and the eighth response may be an FT request and an FT response, respectively.

[0179] The non-AP MLD sends a 9th request to the current AP MLD, and the current AP MLD transparently transmits the 9th request to the target AP MLD via the DS. The 9th request is used to negotiate link operation parameters, etc., between the non-AP MLD and the target AP MLD. The target AP MLD sends a 9th response to the current AP MLD via the DS, and the current AP MLD sends the 9th response to the non-AP MLD. The 9th response includes link operation parameters, etc., between the non-AP MLD and the target AP MLD. In this embodiment, the 9th request and the 9th response may be an FT reassociation request and an FT reassociation response, respectively.

[0180] In the design, as shown in Figure 9, the aforementioned FT action frames (including, but not limited to, the aforementioned FT query requests, FT query responses, FT requests, FT responses, FT reassociation requests, and FT reassociation responses) that are transparently transmitted between the non-AP MLF and the target AP MLD via the DS and the current AP MLD include at least one of the following fields: category, action, MAC address of the non-AP MLD, MAC address of the target AP MLD, and frame body.

[0181] The category field indicates the category to which the FT action frame belongs. The FT action field contains a value corresponding to the FT, and different values ​​are set for each FT action field corresponding to a different FT action frame. See Table 1 for example. [Table 1]

[0182] When the FT action frame in Figure 9 is used as an FT reassociation request, the value set in the FT action field is 7. When the action frame in Figure 9 is used as an FT reassociation response, the value set in the FT action field is 8. The aforementioned FT query requests, FT query responses, FT requests, FT responses, etc., may be in the format of the FT action frame in Figure 9. The difference is that the FT action field values ​​in Table 1 are set to the corresponding values.

[0183] The non-AP MLD field contains the MAC layer address of the non-AP MLD. Specifically, the MAC address may be the upper MAC layer address, lower MAC layer address, etc., of the non-AP MLD. This is not limited. The MAC address of the target AP MLD contains the MAC layer address of the target AP MLD, and the MAC layer address may be the upper MAC layer address, lower MAC layer address, etc., of the target AP MLD.

[0184] The frame body field carries the frame body corresponding to the FT action frame.

[0185] In the embodiment, as shown in Table 2, the frame body of the FT reassociation request frame carries at least one piece of information as follows: [Table 2]

[0186] In the embodiment, as shown in Table 3, the frame body of the FT reassociation response carries at least one piece of information: [Table 3]

[0187] In this embodiment of the present application, if the FT reassociation request and FT reassociation response are transmitted transparently via DS in the design, the implementation is as follows:

[0188] 1. The frame body of the FT reassociation request and / or the frame body of the FT reassociation response does not need to carry OCI, and since OCI is mainly used for channel information verification, the signaling overhead of the FT reassociation request and / or FT reassociation response is reduced.

[0189] 2. After the current AP MLD and target AP MLD have established a provisional association based on the FT reassociation request and FT reassociation response, the initial state of the second transmission link established between the non-AP MLD and the target AP MLD is energy-saving mode, and the state of the second transmission link is doze mode.

[0190] 3. The mobility domain element (MDE) in the frame body of the FT reassociation request and / or the frame body of the frame reassociation response carries 1 bit of instruction information. This instruction information indicates whether OS (over-the-DS) provisional association is supported.

[0191] Step 806: The non-AP MLD triggers a path switch. The non-AP MLD sends an STA-AP mapping request frame to the target AP MLD. The STA-AP mapping request frame may be used to request the target AP MLD to perform a path switch. See the third request above for details on the STA-AP mapping request frame.

[0192] Unlike the procedure in Figure 7a, in the procedure in Figure 8, step 806, when the non-AP MLD sends the STA-AP mapping request frame to the target AP MLD, includes the non-AP MLD sending the STA-AP mapping request frame to the current AP MLD. The current AP MLD sends the STA-AP mapping request frame to the target AP MLD via transparent transmission of the DS.

[0193] Step 807: The target AP MLD sends a context transfer request to the current AP MLD.

[0194] Step 808: The current AP MLD sends a context forwarding response to the target AP MLD. Refer to the previous description for the contents carried in the context forwarding response.

[0195] Step 809: The target AP MLD sends a DS-STA notification request to the DS.

[0196] Upon receiving a DS-STA notify request, the DS may update its stored mapping relationship from the mapping relationship between the non-AP MLD and the current AP MLD to the mapping relationship between the non-AP MLD and the target AP MLD. The DS then disconnects the data path with the current AP MLD and establishes a data path with the target AP MLD. For details on DS-STA notify requests, please refer to the description above in Request 4.

[0197] Step 8010: The current AP MLD removes the context of the non-AP MLD.

[0198] In the embodiment, if the non-AP MLD decides to trigger a path switch in step 806, an isolation frame may be further sent to the current AP MLD. See the fifth request above for details on the isolation frame. The current AP MLD may send a DS-STA notify request for deletion to the DS. The DS deletes the mapping relationship between the non-AP MLD and the current AP MLD that is held in the DS.

[0199] In the procedure shown in Figure 8, a first transmission link exists between the non-AP MLD and the current AP MLD before roaming or switching. During the roaming or switching process, a second transmission link may be established between the non-AP MLD and the target AP MLD via transparent transmission of the DS and / or the current AP MLD. The second transmission link includes non-AP MLD -> target AP MLD. After roaming or switching is complete, uplink data and / or downlink data are transmitted between the non-AP MLD and the target AP MLD via the second transmission link. In the design, after step 8011, i.e., after the target AP MLD sends the STA-AP mapping response frame to the non-AP MLD, the uplink data and / or downlink data are transmitted between the target AP MLD and the non-AP MLD via a second transmission link, and the target AP MLD and the non-AP MLD encrypt / decrypt the uplink data and / or downlink data using a second key negotiated by the target AP MLD and the non-AP MLD, and the corresponding data is transmitted via the second transmission link.

[0200] In the foregoing description of this application, the solution of Embodiment 2 is introduced for the link quality and / or EMLSR type of a single wireless non-AP MLD. In possible embodiments, the solution of Embodiment 2 is not limited to the two types of non-AP MLDs described above. For example, the solution provided in Embodiment 2 may be used for a non-AP MLD that can simultaneously receive / transmit data with multiple AP MLDs. This is not limited.

[0201] In the solution of Embodiment 2, the non-AP MLD is not limited to those capable of simultaneously receiving / transmitting data with multiple AP MLDs. The solution can also be applied to non-AP MLDs that can only transmit data with one AP MLD at a time, further improving the roaming performance of non-AP MLDs, and in particular, improving the roaming performance of non-AP MLDs including single wireless links and EMLSR non-AP MLDs.

[0202] [Embodiment 3]

[0203] In Embodiment 1 or Embodiment 2, the beacon measurement request sent by the current AP MLD to the non-AP MLD may include information indicating the corresponding link of the serving AP. In the embodiment, upon receiving the beacon measurement request, the non-AP MLD may perform beacon measurements for each link of the non-AP. In the design, the non-AP MLD may report the link quality of all measured links to the current AP MLD. Alternatively, upon obtaining the link quality of each link, the non-AP MLD compares the link quality of the current link with the link quality of the corresponding link of the serving AP indicated in the beacon measurement request. The non-AP MLD reports the link quality of a link to the current AP MLD only if the link quality of the current link is higher than or equal to the link quality of the corresponding link of the serving AP. Alternatively, the non-AP MLD does not report the link quality of the corresponding link if the link quality of the current link is lower than the link quality of the corresponding link of the serving AP. This design primarily considers the following: a non-AP MLD reports the measured link quality of a link to the current AP MLD, and the current AP MLD selects a target AP MLD that meets the criteria based on the link quality reported by the current AP MLD. If the link quality of a link is lower than the link quality of the corresponding link on the serving AP, the link is considered to have poor link quality and is not suitable to become a target AP MLD for switching. In this case, the overhead of reporting beacon measurement results is reduced because the non-AP MLD does not need to report the beacon measurement results for the poor quality link.

[0204] In this embodiment, the current AP MLD may send a radio measurement request frame to the non-AP MLD via the link. After receiving the radio measurement request frame, the non-AP MLD may perform the corresponding measurement on the non-AP MLD's link and send a radio measurement report frame to the current AP MLD. The radio measurement report frame includes the measurement results of the measurement performed by the non-AP MLD.

[0205] In the design, as shown in Figure 10, the radio measurement request frame includes at least one field from the following: category, radio measurement action, dialog token, number of repetitions, or measurement request elements.

[0206] The category field may indicate the category to which the corresponding wireless measurement request frame belongs. For example, the wireless measurement request frame may be a relevant frame used for wireless measurement or a relevant frame used for roaming.

[0207] A wireless measurement action may indicate the type of wireless measurement request. For example, a wireless measurement action may indicate that the corresponding frame is a request frame or a measurement frame. Indeed, in this embodiment of the present application, the wireless measurement request frame shown in Figure 10 is used to request a non-AP MLD to perform a wireless measurement. In this case, the type of frame indicated by the wireless measurement action is a request frame.

[0208] The dialog token is used to identify the correspondence between the request frame and the response frame. In the embodiment, the response frame may be in the format shown in Figure 10. The dialog token carried in pairs with the request frame and other frames has the same value.

[0209] The repeat count may indicate the number of times the wireless measurement is repeated. For example, if the repeat count is set to 0, it indicates that the non-AP MLD does not need to repeat the measurement and only needs to perform it once. Alternatively, if the repeat count is set to 65535, it indicates that the non-AP MLD needs to repeat the measurement until the measurement is canceled. The repeat count field is an example. In other words, the frame format shown in Figure 10 does not necessarily have to include the repeat count field.

[0210] Measurement request elements are used to request beacon measurements or to indicate the received signal strength indication (RSSI) of a channel. In the design, if a measurement request element instructs a non-AP MLD to perform an RSSI measurement, the non-AP MLD may report the measured RSSI of the link to the current AP MLD. That is, in Embodiments 1 and 2, in addition to instructing the non-AP MLD to perform a beacon measurement, the current AP MLD may further instruct the non-AP MLD to report the RSSI of the link measured by the non-AP MLD, etc. Alternatively, if a measurement request element instructs a non-AP MLD to perform a beacon measurement, the non-AP MLD may jump to the channel of the link that needs to be measured in order to send a probe request. The current AP MLD returns a probe response on the corresponding link. Based on the received probe response, the non-AP MLD determines the link quality of the corresponding link. Alternatively, the non-AP MLD may directly listen for beacon frames on the link that needs to be measured. non-AP MLD determines the link quality of the corresponding link based on listened beacon measurements.

[0211] Furthermore, in the frame format of Figure 10, if the measurement request element instructs the non-AP MLD to perform a beacon measurement, the frame format of Figure 10 may further include a beacon report subelement. In the embodiment, the beacon report subelement includes a report condition field, a threshold / offset reference field, etc. In the design, if the value of the report condition field is set to a first value, the first value includes but is not limited to 7, which indicates that the beacon measurement result will be reported to the current AP MLD when the difference between the received signal-to-noise ratio of the corresponding link measured by the non-AP MLD and the received signal-to-noise ratio of the current serving AP is greater than or equal to the value in the threshold / offset reference field. Alternatively, if the difference between the received signal-to-noise ratio of the corresponding link measured by the non-AP MLD and the received signal-to-noise ratio of the current serving AP is less than the value in the threshold / offset reference field, the beacon measurement result will not be reported to the current AP.

[0212] In the design, in a multilink scenario, the current AP MLD may send beacon measurement requests to the non-AP MLD via any affiliated AP that has a link with the non-AP MLD. In this case, the serving AP may be ambiguous to the non-AP MLD. In this case, the non-AP MLD cannot clearly determine which AP will be the serving AP for comparison of the received signal-to-noise ratio. To solve this problem, the following solution is proposed.

[0213] Solution 1: In addition to the first value and / or threshold / offset reference field, the frame format shown in Figure 10 further includes a link identifier (link ID) field, as shown in Figure 11. The link identifier field may indicate the corresponding link of the serving AP. Furthermore, in addition to the link identifier field, a reserved field may be included. This field may be called the link ID info field. The link identifier field may occupy 4 bits, and the reserved field may occupy 4 bits. Alternatively, the frame format shown in Figure 10 carries a multi-link operation (MLO) link information subelement. As shown in Figure 11, the subfield includes an element identifier (element ID), length, element ID extension, and link ID bitmap.

[0214] Solution 2: The links on which the current AP MLD sends beacon measurement requests are restricted, and the AP corresponding to the link from which the beacon measurement request is sent is designated as the serving AP. In other words, on the non-AP MLD side, if the non-AP MLD side receives a beacon measurement request for a link, the AP corresponding to that link becomes the serving AP.

[0215] Following the method described above, non-AP MLDs can report beacon measurement results that meet the criteria. Compared to methods that report beacon measurement results for all links, this method may reduce reporting overhead.

[0216] Furthermore, the following points should be noted regarding this embodiment of the present application:

[0217] 1. This section primarily describes the differences between different procedures. Please refer to each other when describing different procedures.

[0218] 2. In the procedures shown in Figures 3, 5, 7a, and 8, the execution order of the different steps is not restricted.

[0219] 3. The procedures in Figures 3, 5, 7a, and 8 may include more or fewer steps than those described in the flowchart or text description. This is not limited.

[0220] In the embodiments provided herein, the methods provided in the embodiments have been described individually from the perspective of device-to-device interaction. To implement the methods provided in the embodiments herein, a non-AP MLD, current AP MLD, target AP MLD, etc., may include hardware structures and / or software modules, and the aforementioned functions are implemented in the form of hardware structures, software modules, or a combination of hardware structures and software modules. Whether a particular function among the aforementioned functions is performed using a hardware structure, a software module, or a combination of hardware structures and software modules depends on the design constraints of the specific application of the technical solution.

[0221] Figures 12 and 13 are diagrams of the structure of possible devices according to the embodiments of the present application, respectively. These communication devices may implement one or more corresponding functions in the method embodiments described above. For example, functions implemented by a target AP MLD, a current AP MLD, or a non-AP MLD may achieve the advantageous effects of the method embodiments described above.

[0222] As shown in Figure 12, the communication device 1200 includes a processing unit 1210 and a transceiver unit 1220.

[0223] For example, the processing unit 1210 may also be called a processor, processing board, processing module, or processing unit. The transceiver unit 1220 may also be called a transceiver, transceiver machine, transceiver module, transceiver device, communication unit, etc. Furthermore, the transceiver unit 1220 may include at least one of a transmitting unit or a receiving unit. The transmitting unit and the receiving unit may be integrated together, or they may be two separate units, etc.

[0224] In the design, the communication device 1200 is configured to implement the functions of the target AP MLD shown in Figure 13. Specifically, the transceiver unit 1220 is configured to receive the first downlink data transmitted by the current AP MLD. The first downlink data is encrypted using a first key, which is a key negotiated by the current AP MLD and the non-AP MLD, and the target AP MLD is the AP MLD of the non-AP MLD after the basic service set BSS transition. The processing unit 1210 is configured to perform lower medium access control LMAC layer processing and physical layer processing on the first downlink data to obtain the second downlink data. The transceiver unit 1220 is further configured to transmit the second downlink data to the non-AP MLD.

[0225] In the design, the communication device 1200 is configured to implement the functions of the current AP MLD shown in Figure 3. Details are as follows:

[0226] The transceiver unit 1220 is configured to receive third downlink data transmitted by the distributed system DS. The processing unit 1210 is configured to encrypt the third downlink data using a first key and obtain the first downlink data. The first key is a key negotiated by the current AP MLD and non-AP MLD. The transceiver unit 1220 is further configured to transmit the first downlink data to the target AP MLD. The target AP MLD is the AP MLD of the non-AP MLD after the basic service set BSS transition.

[0227] In the design, the communication device 1200 is configured to implement the functions of the non-AP MLD shown in Figure 3. Specifically, the transceiver unit 1220 is configured to receive data transmitted by the current AP MLD by using the target access point AP MLD. The target AP MLD is the AP MLD of the non-AP MLD after the basic service set BSS transition, and the data is encrypted by the current AP MLD using a first key, which is a key negotiated between the current AP MLD and the non-access point non-AP MLD. The processing unit 1210 is configured to decrypt the data using the first key.

[0228] In the design, the communication device 1200 is configured to implement the functions of the target AP MLD shown in Figure 5. Details are as follows:

[0229] The transceiver unit 1220 is configured to receive first uplink data transmitted by a non-access point (non-AP) MLD. The first uplink data is encrypted using a first key, which is a key negotiated by the current AP MLD and non-AP MLD, and the target AP MLD is the AP MLD of the non-AP MLD after the basic service set (BSS) transition. The processing unit 1210 is configured to perform physical layer processing and lower media access control (LMAC) layer processing on the first uplink data to determine the second uplink data. The transceiver unit 1220 is configured to transmit the second uplink data to the current AP MLD.

[0230] In the design, the communication device 1200 is configured to implement the functions of the current AP MLD shown in Figure 5. Details are as follows:

[0231] The transceiver unit 1220 is configured to receive the second uplink data transmitted by the target AP MLD. The target AP MLD is the AP MLD of the non-AP MLD after the basic service set BSS transition. The processing unit 1210 is configured to perform higher media access control UMAC layer processing on the second uplink data and decrypt the second uplink data using a first key to determine the third uplink data. The first key is a key negotiated by the current AP MLD and non-AP MLD. The transceiver unit 1220 is further configured to transmit the third uplink data to the distributed system DS.

[0232] In the design, the communication device 1200 is configured to implement the functions of the non-AP MLD shown in Figure 5. Details are as follows:

[0233] The processing unit 1210 is configured to determine the first uplink data by encrypting the uplink data to be transmitted using a first key. The first key is a key negotiated by the current access point AP MLD and non-AP MLD. The transceiver unit 1220 is configured to transmit the first uplink data to the current AP MLD using a target AP MLD. The target AP MLD is the AP MLD of the non-AP MLD after the basic service set BSS transition.

[0234] For a more detailed description of the processing unit 1210 and the transceiver unit 1220, please refer to the description in Figure 3 or Figure 5 in the method embodiment described above. Further details are not described again here.

[0235] In this embodiment of the present application, the division into units is an example and merely a logical functional division. In actual implementation, other division methods may be used. Furthermore, the functional units in the embodiment of the present application may be integrated into a single physical device (e.g., a processor), or each functional unit may be an independent physical device, or two or more units may be integrated into a single unit for implementation. The integrated unit may be implemented in hardware form or in the form of a software functional module or the like.

[0236] Figure 13 is a diagram of another structure of the communication device 1300 according to an embodiment of the present application. For example, the communication device 1300 shown in Figure 13 may be an embodiment of the hardware circuit of the communication device 1200 shown in Figure 12. For simplicity of explanation, Figure 13 shows only the main parts of the communication device.

[0237] As shown in Figure 13, the communication device 1300 includes a processor 1310 and an interface circuit 1320. The processor 1310 and the interface circuit 1320 are coupled to each other.

[0238] For example, the processor 1310 may be a central processing unit (CPU), or it may be another general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), or another programmable logic device, a transistor logic device, a hardware component, or any combination thereof. The general-purpose processor may be a microprocessor, or any conventional processor, etc. The interface circuit 1320 may be a transceiver, an input / output circuit, etc.

[0239] Optionally, the communication device 1300 may further include a memory 1330 configured to store instructions executed by the processor 1310, input data necessary for the processor 1310 to execute instructions, or data generated after the processor 1310 has executed instructions. For example, instructions may also be called computer programs, computer program code, etc.

[0240] For example, memory 1330 may be random access memory (RAM), flash memory, read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EPROM, EEPROM), registers, hard disks, removable hard disks, CD-ROMs, or other forms of storage media well known in the art.

[0241] When the communication device 1300 is configured to implement the target AP MLD, current AP MLD, or non-AP MLD method shown in Figure 3 or Figure 5, the processor 1310 is configured to implement the functions of the processing unit 1210, and the interface circuit 1320 is configured to implement the functions of the transceiver unit 1220.

[0242] In the design, the interface circuit 1320 is configured to receive signals from communication devices other than the communication device 1300 and transmit those signals to the processor 1310, or to transmit signals from the processor 1310 to communication devices other than the communication device. The processor 1310 is configured to implement the functions of the target AP MLD, current AP MLD, or non-AP MLD shown in Figure 3 or Figure 5 by using logic circuits or by executing code instructions.

[0243] Embodiments of the present invention further provide a communication device, the communication device including a processor and memory. The processor is coupled to memory and is configured to implement the functions of the target AP MLD, current AP MLD, or non-AP MLD in Figure 3 or Figure 5. For example, the processor may execute instructions in memory so that the communication device implements one or more functions in the method embodiments described above, for example, functions implemented by the target AP MLD, current AP MLD, or non-AP MLD in Figure 3 or Figure 5. For example, a storage medium may be coupled to the processor so that the processor can read information from and write information to the storage medium. Indeed, the storage medium may be a component of the processor. The processor and storage medium may be located in an ASIC. Furthermore, the ASIC may be located in the target AP MLD, current AP MLD, or non-AP MLD in Figure 3 or Figure 5. Alternatively, the processor and storage medium may reside in the target AP MLD, current AP MLD, or non-AP MLD in Figure 3 or Figure 5 and function as discrete components.

[0244] Embodiments of the present invention further provide a computer-readable storage medium. The computer-readable storage medium stores instructions, which may also be called computer programs, computer program code, etc. The instructions are executed by a computer, thereby causing the computer to perform the functions of the target AP MLD, current AP MLD, or non-AP MLD in Figure 3 or Figure 5 in the aforementioned method embodiment.

[0245] Optionally, the computer may be a general-purpose computer, a dedicated computer, a computer network, a network device, a user device, or another programmable device. Computer programs or instructions may be stored in computer-readable storage media, or transmitted from one computer-readable storage medium to another. For example, computer programs or instructions may be transmitted by wire or wirelessly from one website, computer, server, or data center to another website, computer, server, or data center. The computer-readable storage medium may be any available medium accessible to the computer, or a data storage device incorporating one or more available media, such as a server or data center. The available media may be magnetic media, such as floppy disks, hard disks, or magnetic tapes, or optical media, such as digital video discs, or semiconductor media, such as solid-state devices. The computer-readable storage medium may be volatile or non-volatile storage media, or may include two types of storage media, namely volatile and non-volatile storage media.

[0246] Embodiments of the present application further provide a computer program product including a computer program or instruction. When the computer program or instruction is executed on a computer, the target AP MLD, current AP MLD, or non-AP MLD method shown in Figure 3 or Figure 5 is performed. For example, the computer program product includes one or more computer programs or instructions. When the computer program or instruction is loaded and executed on a computer, all or part of the procedure or function of the target AP MLD, current AP MLD, or non-AP MLD in Figure 3 or Figure 5 in embodiments of the present application is performed.

[0247] The methods in all or part of the embodiments of this application may be implemented by software, hardware, firmware, or any combination thereof. When software is used to implement the method, the method may be implemented in whole or in part as a computer program product.

[0248] Embodiments of the present invention further provide a chip, which includes a processor, which is coupled to memory, which is configured to execute computer programs or instructions stored in memory, thereby enabling the chip to implement the functions of a target AP MLD, current AP MLD, or non-AP MLD as shown in Figure 3 or Figure 5.

[0249] Embodiments of the present invention further provide a communication system including a first communication device, a second communication device, and a third communication device.

[0250] The first communication device may implement the functions of the target AP MLD shown in Figure 3 or Figure 5. The second communication device may implement the functions of the current AP MLD shown in Figure 3 or Figure 5. The third communication device may implement the functions of the non-AP MLD shown in Figure 3 or Figure 5. For specific structures of the first, second, or third communication devices, please refer to the above description, for example, the structural description in Figure 12 or Figure 13.

[0251] In the description of this application, "at least one" means one or more, and "multiple" means two or more. "and / or" indicates an association between related objects, indicating that there may be three possible relationships. For example, A and / or B can indicate that only A exists, both A and B exist, or only B exists, in the following three cases: where A and B may be singular or plural. In the text description of this application, the letter " / " generally represents an "OR" relationship between related objects. "Containing at least one of A, B, or B" can mean containing A, containing B, containing C, containing A and B, containing A and C, containing B and C, and containing A, B, and C.

[0252] The numbers used in the embodiments of this application are used for distinction only to facilitate explanation and do not limit the scope of the embodiments. The sequence numbers of the processes described above do not indicate the execution order, and the execution order of the processes should be determined based on the function and internal logic of the processes.

[0253] This application claims priority to Chinese Patent Application No. 202310949736.2, filed with the China National Intellectual Property Administration on 29 July 2023, with the title of the invention being "COMMUNICATION METHOD AND APPARATUS," which is incorporated herein by reference in its entirety.

Claims

1. A method of communication, The target access point (AP) multilink device (MLD) receives first downlink data from the current AP MLD, the first downlink data being encrypted using a first key, the first key being a key negotiated by the current AP MLD and the non-access point (non-AP MLD), and the target AP MLD being the AP MLD of the non-AP MLD after the transition of the basic service set (BSS). The target AP MLD performs lower-level media access control LMAC layer processing and physical layer processing on the first downlink data to acquire the second downlink data. The target AP MLD transmits the second downlink data to the non-AP MLD. A method of having.

2. A method of communication, The target access point (AP) multilink device (MLD) receives first uplink data from a non-access point (non-AP MLD), the first uplink data being encrypted using a first key, the first key being a key negotiated by the current AP MLD and the non-AP MLD, and the target AP MLD being the AP MLD of the non-AP MLD after the transition of the basic service set (BSS). The target AP MLD performs physical layer processing and lower media access control LMAC layer processing on the first uplink data to determine the second uplink data. The target AP MLD transmits the second uplink data to the current AP MLD. A method of having.

3. A first transmission link exists between the aforementioned non-AP MLD and the aforementioned current AP MLD, and the method is as follows: The first request is received by the target AP MLD, and the first request is used to request the establishment of a second transmission link between the non-AP MLD and the target AP MLD. The second transmission link is established with the non-AP MLD by the target AP MLD. It further has, The method according to claim 1 or 2.

4. The first request includes instruction information for enabling dual-link transmission of the non-AP MLD, and the dual-link includes the first transmission link and the second transmission link. The method according to claim 3.

5. The target AP MLD further comprises sending a second request to the current AP MLD, the second request being used to request the non-AP MLD to enable the dual-link transmission, the second request including the maximum MAC Layer Protocol data unit (MPDU) length supported by the target AP MLD, and / or the maximum number of aggregated MAC Layer Service data units (MSDU) allowed by the target AP MLD. The method according to any one of claims 1 to 4.

6. The third request is received by the target AP MLD, and the third request is used to request that the non-AP MLD trigger a path switch. The target AP MLD sends a fourth request to the distributed system DS, the fourth request being used to request the DS to update the stored mapping relationship between the non-AP MLD and the current AP MLD to the mapping relationship between the non-AP MLD and the target AP MLD. The method according to any one of claims 1 to 5, further comprising:

7. One or both of the first and third requests originate from the non-AP MLD, and one or both of the first and third requests are transmitted via the air interface between the non-AP MLD and the target AP MLD, or via the current AP MLD and the DS. The method according to any one of claims 3 to 6.

8. When the first request is transmitted via the current AP MLD and the DS, the first request does not include operating channel information OCI. The method according to claim 7.

9. After the target AP MLD receives the third request, and before the target AP MLD sends the fourth request to the DS, the method: The target AP MLD sends a context transfer request to the current AP MLD, The target AP MLD receives a context transfer response from the current AP MLD, and the context transfer response includes context information of the non-AP MLD. It further has, The method according to any one of claims 6 to 8.

10. The context forwarding response further includes at least one of the following: a block acknowledgment protocol for the traffic identifier TID, the window start position of the transmission buffer for the TID, the window size of the transmission buffer for the TID, the window start position of the uplink receive end scoreboard, the window size of the uplink receive end scoreboard, the window start position of the receive sort buffer, the window size of the receive sort buffer, the currently received maximum packet number PN value, or the uplink replay counter. The method according to claim 9.

11. After the transmission path of the non-AP MLD is switched from the first transmission path to the second transmission path, the non-AP MLD and the target AP MLD encrypt / decrypt the uplink data and / or downlink data using a second key negotiated by the non-AP MLD and the target AP MLD. The method according to any one of claims 1 to 10.

12. A method of communication, The current access point AP multilink device MLD receives third downlink data from the distributed system DS, The current AP MLD encrypts the third downlink data using the first key to obtain the first downlink data, and the first key is a key negotiated by the current AP MLD and the non-access point non-AP MLD. The current AP MLD transmits the first downlink data to the target AP MLD, and the target AP MLD is the AP MLD of the non-AP MLD after the transition of the basic service set (BSS). A method of having.

13. A method of communication, The current access point (AP) multilink device (MLD) receives second uplink data from the target AP MLD, and the target AP MLD is the AP MLD of a non-access point (non-AP MLD) after the transition of the basic service set (BSS). The current AP MLD performs upper-level media access control (UMAC) layer processing on the second uplink data, and the third uplink data is determined by decrypting the second uplink data using the first key, wherein the first key is a key negotiated by the current AP MLD and the non-AP MLD. The current AP MLD transmits the third uplink data to the distributed system DS. A method of having.

14. A first transmission link exists between the current AP MLD and the non-AP MLD, and the method is as follows: The current AP MLD further includes receiving a second request from the target AP MLD, the second request being used to request the enablement of dual-link transmission for the non-AP MLD, the second request including the maximum media access control MAC layer protocol data unit (MPDU) length supported by the target AP MLD, and / or the maximum number of aggregated MAC layer service data units (MSDUs) allowed by the target AP MLD, the dual-link including the first transmission link and the second transmission link between the non-AP MLD and the target AP MLD. The method according to claim 12 or 13.

15. The current AP MLD receives a fifth request from the non-AP MLD, the fifth request being used to request the disconnection of the first transmission link between the non-AP MLD and the current AP MLD, the fifth request including first instruction information, the first instruction information instructing the current AP MLD to reserve the non-AP MLD's block acknowledgment BA information and / or context information and to buffer data not from the non-AP MLD, The current AP MLD sends a sixth request to the DS, the sixth request being used to request the deletion of the mapping relationship stored in the DS between the non-AP MLD and the current AP MLD. The method according to any one of claims 12 to 14, further comprising:

16. The current AP MLD receives a context transfer request from the target AP MLD, The current AP MLD sends a context transfer response to the target AP MLD, and the context transfer response includes context information of the non-AP MLD. The method according to any one of claims 12 to 15, further comprising the above.

17. The context forwarding response further includes at least one of the following: a block acknowledgment protocol for the traffic identifier TID, the window start position of the transmission buffer for the TID, the window size of the transmission buffer for the TID, the window start position of the uplink receive end scoreboard, the window size of the uplink receive end scoreboard, the window start position of the receive sort buffer, the window size of the receive sort buffer, the currently received maximum packet number PN value, or the uplink replay counter. The method according to claim 16.

18. The current AP MLD further transmits a beacon measurement request to the non-AP MLD, the beacon measurement request including instruction information for the corresponding link of the serving AP. The method according to any one of claims 12 to 17.

19. The current AP MLD further comprises sending a seventh request to the non-AP MLD, the seventh request including second instruction information, the second instruction information instructing the non-AP MLD to reserve the BA information and / or the context information of the non-AP MLD and to buffer the data that is not from the non-AP MLD. The method according to any one of claims 12 to 18.

20. A method of communication, The non-access point (non-AP) multilink device (MLD) receives data from the current access point (AP) MLD by using the target access point (AP) MLD, wherein the target AP MLD is the AP MLD of the non-AP MLD after the transition of the basic service set (BSS), the data is encrypted by the current AP MLD using a first key, and the first key is a key negotiated by the current AP MLD and the non-access point (non-AP) MLD. The non-AP MLD allows the data to be decrypted by using the first key. A method of having.

21. A method of communication, The non-access point (non-AP) multilink device (MLD) encrypts the uplink data to be transmitted using a first key to determine the first uplink data, wherein the first key is a key negotiated by the current access point (AP) MLD and the non-AP MLD. The non-AP MLD transmits the first uplink data to the current AP MLD by using the target AP MLD, and the target AP MLD is the AP MLD of the non-AP MLD after the transition of the basic service set (BSS). A method of having.

22. A first transmission link exists between the aforementioned non-AP MLD and the aforementioned current AP MLD, and the method is as follows: The non-AP MLD further comprises sending a first request, the first request being used to request the establishment of a second transmission link between the non-AP MLD and the target AP MLD. The method according to claim 20 or 21.

23. The first request includes instruction information for enabling the dual-link transmission of the non-AP MLD, and the dual-link includes the first transmission link and the second transmission link. The method according to claim 22.

24. The non-AP MLD further comprises sending a third request, the third request being used to request that the non-AP MLD trigger a path switch. The method according to any one of claims 20 to 23.

25. One or both of the first request and the third request are transmitted to the target AP MLD, and one or both of the first request and the third request are transmitted via the air interface between the non-AP MLD and the target AP MLD, or via the current AP MLD and the DS. The method according to any one of claims 22 to 24.

26. When the first request is transmitted via the current AP MLD and the DS, the first request does not include operating channel information OCI. The method according to claim 25.

27. The non-AP MLD further comprises sending a fifth request to the current AP MLD, the fifth request including first instruction information, the first instruction information instructing the current AP MLD to reserve block acknowledgment BA information and / or context information of the non-AP MLD and to buffer data that is not from the non-AP MLD. The method according to any one of claims 20 to 26.

28. The non-AP MLD further comprises receiving a beacon measurement request from the current AP MLD, the beacon measurement request including instruction information for the corresponding link of the serving AP. The method according to any one of claims 20 to 27.

29. The non-AP MLD further includes receiving a seventh request from the current AP MLD, the seventh request including second instruction information, the second instruction information instructing the non-AP MLD to reserve the BA information and / or the context information of the non-AP MLD and to buffer data that is not from the non-AP MLD. The method according to any one of claims 20 to 28.

30. After the transmission path of the non-AP MLD is switched from the first transmission path to the second transmission path, the non-AP MLD and the target AP MLD encrypt / decrypt the uplink data and / or downlink data using a second key negotiated by the non-AP MLD and the target AP MLD. The method according to any one of claims 20 to 29.

31. A communication device having a unit configured to implement the method described in any one of claims 1 to 11, or a unit configured to implement the method described in any one of claims 12 to 19, or a unit configured to implement the method described in any one of claims 20 to 30.

32. A communication device, A memory configured to store program instructions, A processor configured to execute program instructions so that the communication device performs the method according to any one of claims 1 to 11, or the method according to any one of claims 12 to 19, or the method according to any one of claims 20 to 30. A communication device having the following features.

33. A device having a processor and an interface circuit, The interface circuit is configured to receive signals from devices other than the device in question, transmit those signals to the processor, and transmit signals from the processor to other devices other than the device in question. The processor enables the device to implement the method according to any one of claims 1 to 11, or the method according to any one of claims 12 to 19, or the method according to any one of claims 20 to 30, by using logic circuits or by executing code instructions. Device.

34. The computer stores instructions, and when such instructions are executed by the computer, the computer can perform the method according to any one of claims 1 to 11, or the method according to any one of claims 12 to 19, or the method according to any one of claims 20 to 30. Computer-readable storage medium.

35. Including computer programs or instructions, When the computer program or instruction is executed by the device, the method described in any one of claims 1 to 11 is executed, or the method described in any one of claims 12 to 19 is executed, or the method described in any one of claims 20 to 30 is executed. Computer program products.

36. A chip including a processor, The processor is coupled to memory and executes a computer program or instruction stored in the memory to cause the communication device including the chip to perform the method described in any one of claims 1 to 11, or the method described in any one of claims 12 to 19, or the method described in any one of claims 20 to 30. Tip.

37. A first communication device configured to perform the method described in any one of claims 1 to 11, A second communication device configured to perform the method described in any one of claims 12 to 19, A third communication device configured to perform the method described in any one of claims 20 to 30, and A communication system that includes this.

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