Communication method and device

Abstract

The embodiment of the invention relates to a communication method and device, and the method comprises the steps that an AP MLD receives first downlink data sent by a current AP MLD, the first downlink data is data encrypted by employing a first secret key, the first secret key is a secret key negotiated by the current AP MLD and a non-AP MLD, and a target AP MLD is an AP MLD after the non-AP MLD is transferred in a basic service set (BSS); and the target AP MLD performs low media access control (LMAC) layer and physical layer processing on the first downlink data to obtain second downlink data. By adopting the method and the device provided by the embodiment of the invention, the roaming performance of the non-AP MLD can be improved.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of communication technology, and in particular, to a communication method and device. Background Art

[0002] Due to factors such as the mobility of non-AP multi-link devices (MLDs), non-AP MLDs need to switch their associated access point (AP) MLDs. During roaming, non-AP MLDs often experience speed drops (i.e., reduced transmission rates). Improving the roaming performance of non-AP MLDs is an important research direction for next-generation wireless fidelity (Wi-Fi) roaming. Summary of the invention

[0003] The embodiments of the present application provide a communication method and apparatus, during roaming, data can be transmitted between a current AP MLD and a target AP MLD, thereby improving the roaming performance of a non-AP MLD.

[0004] In a first aspect, a communication method is provided, including: a target access point AP multi-link device MLD receives first downlink data sent by a current AP MLD, the first downlink data is data encrypted with a first key, the first key is a key negotiated between the current AP MLD and a non-access point non-AP MLD, and the target AP MLD is the AP MLD of the non-AP MLD after the basic service set BSS is transferred; the target AP MLD performs low media access control LMAC layer and physical layer processing on the first downlink data to obtain second downlink data; the target AP MLD sends the second downlink data to the non-AP MLD.

[0005] According to a second aspect, a communication method is provided, including: a target access point AP multi-link device MLD receives first uplink data sent by a non-access point non-AP MLD, the first uplink data is data encrypted with a first key, the first key is a key negotiated between 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 is transferred; the target AP MLD processes the first uplink data at the physical layer and the low media access control LMAC layer to determine second uplink data; the target AP MLD sends the second uplink data to the current AP MLD.

[0006] In one design, there is a first transmission link between the non-AP MLD and the current AP MLD, and the method also includes: the target AP MLD receives a first request, wherein the first request is used to request establishment of a second transmission link between the non-AP MLD and the target AP MLD; and the target AP MLD establishes a second transmission link with the non-AP MLD.

[0007] In one design, the first request includes indication information for enabling dual-link transmission of the non-AP MLD, where the dual-link includes the first transmission link and the second transmission link.

[0008] In one design, it also includes: the target AP MLD sends a second request to the current AP MLD, the second request is used to request to enable dual-link transmission of 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 MAC layer service data units MSDU allowed to be aggregated by the target AP MLD.

[0009] In one design, it also includes: the target AP MLD receives a third request, and the third request is used to request to trigger the path switching of the non-AP MLD; the target AP MLD sends a fourth request to the distributed system DS, and 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.

[0010] In one design, the first request and / or the third request is sent by the non-AP MLD, and the first request and / or the third request is transmitted through the air interface between the non-AP MLD and the target AP MLD, or through the current AP MLD and DS.

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

[0012] In one design, after the target AP MLD receives the third request and before the target AP MLD sends the fourth request to the DS, it also includes: the target AP MLD sends a context transfer request to the current AP MLD; the target AP MLD receives a context transfer response sent by the current AP MLD, and the context transfer response includes context information of the non-AP MLD.

[0013] In one design, the context transfer response also includes at least one of the following: a block determination protocol of a service identifier TID, a window starting position of a send buffer area of ​​the TID, a window size of a send buffer area of ​​the TID, a window starting position of an uplink receiving end scoreboard, a window size of the uplink receiving end scoreboard, a window starting position of a receive reordering buffer area, a window size of a receive reordering buffer area, a maximum packet sequence number PN value currently received, or an uplink replay counter.

[0014] In one 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 use a second key negotiated by both parties to encrypt and decrypt uplink data and / or downlink data.

[0015] According to a third aspect, a communication method is provided, including: a current access point AP multi-link device MLD receives third downlink data sent by a distributed system DS; the current AP MLD encrypts the third downlink data using a first key to obtain first downlink data, and the first key is a key negotiated between the current AP MLD and a non-access point non-AP MLD; the current AP MLD sends the first downlink data to a target AP MLD, and the target AP MLD is the AP MLD of the non-AP MLD after the basic service set BSS is transferred.

[0016] In a fourth aspect, a communication method is provided, including: a current access point AP multi-link device MLD receives second uplink data sent by a target AP MLD, wherein the target AP MLD is an AP MLD of a non-access point non-AP MLD after the basic service set BSS is transferred; the current AP MLD performs high media access control UMAC layer processing on the second uplink data, and uses a first key to decrypt the second uplink data to determine third uplink data, wherein the first key is a key negotiated between the current AP MLD and the non-AP MLD; the current AP MLD sends the third uplink data to a distributed system DS.

[0017] In one design, a first transmission link exists between the current AP MLD and the non-AP MLD, further comprising:

[0018] The current AP MLD receives a second request sent by the target AP MLD, where the second request is used to request to enable dual-link transmission of the non-AP MLD, and the second request includes: the maximum media access control MAC layer protocol data unit MPDU length supported by the target AP MLD, and / or the maximum number of MAC layer service data units MSDU allowed to be aggregated by the target AP MLD, and the dual link includes the first transmission link and a second transmission link between the non-AP MLD and the target AP MLD.

[0019] In one design, the further step includes: the current AP MLD receiving a fifth request sent by the non-AP MLD, the fifth request being used to request disconnection of a first transmission link between the non-AP MLD and the current AP MLD, the fifth request including first indication information, the first indication information instructing the current AP MLD to retain block acknowledgment BA information and / or context information of the non-AP MLD and cache data not sent by the non-AP MLD;

[0020] The current AP MLD sends a sixth request to the DS, where the sixth request is used to request deletion of a mapping relationship between the non-AP MLD and the current AP MLD stored in the DS.

[0021] In one design, it also includes: the current AP MLD receives a context transfer request sent by 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.

[0022] In one design, the context transfer response also includes at least one of the following: a block determination protocol of a service identifier TID, a window starting position of a send buffer area of ​​the TID, a window size of a send buffer area of ​​the TID, a window starting position of an uplink receiving end scoreboard, a window size of the uplink receiving end scoreboard, a window starting position of a receive reordering buffer area, a window size of a receive reordering buffer area, a maximum packet sequence number PN value currently received, or an uplink replay counter.

[0023] In one design, the further configuration includes: the current AP MLD sending a beacon measurement request to the non-AP MLD, wherein the beacon measurement request includes indication information of a corresponding link of the serving AP.

[0024] In one design, it also includes: the current AP MLD sends a seventh request to the non-AP MLD, the seventh request includes second indication information, the second indication information instructs the non-AP MLD to retain the BA information and / or context information of the non-AP MLD, and cache the data not sent by the non-AP MLD.

[0025] In a fifth aspect, a communication method is provided, including: a non-access point non-AP multi-link device MLD receives data sent by a current access point AP MLD through a target access point AP MLD, wherein the target AP MLD is the AP MLD of the non-AP MLD after the basic service set BSS is transferred; the data is data encrypted by the current AP MLD using a first key, and the first key is a key negotiated between the current AP MLD and the non-access point non-AP MLD; and the non-AP MLD decrypts the data using the first key.

[0026] In a sixth aspect, a communication method is provided, including: a non-access point non-AP multi-link device MLD uses a first key to encrypt uplink data to be transmitted to determine first uplink data, wherein the first key is a key negotiated between a current access point AP MLD and the non-AP MLD; the non-AP MLD sends the first uplink data to the current AP MLD through a target AP MLD, and the target AP MLD is the AP MLD of the non-AP MLD after the basic service set BSS is transferred.

[0027] In one design, a first transmission link exists between the non-AP MLD and the current AP MLD, further comprising:

[0028] The non-AP MLD sends a first request, where the first request is used to request to establish a second transmission link between the non-AP MLD and the target AP MLD.

[0029] In one design, the first request includes indication information for enabling dual-link transmission of the non-AP MLD, where the dual-link includes the first transmission link and the second transmission link.

[0030] In one design, the non-AP MLD further includes sending a third request, where the third request is used to request triggering of path switching of the non-AP MLD.

[0031] In one design, the first request and / or the third request is sent to the target AP MLD, and the first request and / or the third request is transmitted through the air interface between the non-AP MLD and the target AP MLD, or through the current AP MLD and DS.

[0032] In one design, when the first request is transmitted through the current AP MLD and DS, the first request does not include operating channel information OCI.

[0033] In one design, it also includes: the non-AP MLD sends a fifth request to the current AP MLD, the fifth request includes first indication information, the first indication information instructs the current AP MLD to retain the block acknowledgment BA information and / or context information of the non-AP MLD, and caches the data not sent by the non-AP MLD.

[0034] In one design, it also includes: the non-AP MLD receives a beacon measurement request sent by the current AP MLD, and the beacon measurement request includes indication information of a link corresponding to the serving AP.

[0035] In one design, it also includes: the non-AP MLD receives the seventh request sent by the current AP MLD, the seventh request includes second indication information, the second indication information instructs the non-AP MLD to retain the BA information and / or context information of the non-APMLD, and caches the data not sent by the non-AP MLD.

[0036] In one 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 use a second key negotiated by both parties to encrypt and decrypt uplink data and / or downlink data.

[0037] In one design, in the above aspects, data is sent or received between the current AP MLD and the target AP MLD using a transparent transmission method.

[0038] In a seventh aspect, a device is provided, which can implement the method of the first aspect or the second aspect. For example, the device includes means for executing the corresponding method of the first aspect or the second aspect. The device can be implemented by hardware, software, or by executing the corresponding software implementation by hardware.

[0039] In one design, the apparatus includes a unit for performing the first aspect or the second aspect described above.

[0040] In one design, the device includes a processor and a memory, and the processor is used to execute a computer program or instruction stored in the memory so that the device implements the method of the first aspect or the second aspect above.

[0041] In one design, the device includes a processor and an interface circuit, the interface circuit is used to receive signals from other devices outside the device and transmit them to the processor or send signals from the processor to other devices outside the device, and the processor is used to implement the method in the first or second aspect above through logic circuits or executing code instructions.

[0042] In an eighth aspect, a device is provided, which can implement the method of the third aspect or the fourth aspect. For example, the device includes means for executing the corresponding method of the third aspect or the fourth aspect. The device can be implemented by hardware, software, or by executing the corresponding software implementation by hardware.

[0043] In one design, the apparatus includes a unit for performing the third aspect or the fourth aspect.

[0044] In one design, the device includes a processor and a memory, and the processor is used to execute a computer program or instructions stored in the memory, so that the device implements the method of the third aspect or the fourth aspect above.

[0045] In one design, the device includes a processor and an interface circuit, the interface circuit is used to receive signals from other devices outside the device and transmit them to the processor or send signals from the processor to other devices outside the device, and the processor is used to implement the method in the third aspect or the fourth aspect above through logic circuits or execution code instructions.

[0046] In a ninth aspect, a device is provided, which can implement the method of the fifth aspect or the sixth aspect. For example, the device includes means for executing the corresponding method of the fifth aspect or the sixth aspect. The device can be implemented by hardware, software, or by executing the corresponding software implementation by hardware.

[0047] In one design, the apparatus includes a unit for performing the fifth aspect or the sixth aspect described above.

[0048] In one design, the device includes a processor and a memory, and the processor is used to execute a computer program or instructions stored in the memory, so that the device implements the method of the fifth aspect or the sixth aspect above.

[0049] In one design, the device includes a processor and an interface circuit, the interface circuit is used to receive signals from other devices outside the device and transmit them to the processor or send signals from the processor to other devices outside the device, and the processor is used to implement the method in the fifth or sixth aspect above through logic circuits or execution code instructions.

[0050] In a tenth aspect, a computer-readable storage medium is provided, storing a computer program or instruction. When the computer program or instruction is executed on a computer, the computer implements the method of any one of the first to sixth aspects.

[0051] In an eleventh aspect, a computer program product is provided, comprising a computer program or instructions, which, when executed by a computer, enables the method of any one of the first to sixth aspects to be executed.

[0052] In the twelfth aspect, a chip is provided, comprising a processor, wherein the processor is coupled to a memory and is used to execute a computer program or instruction stored in the memory, so that the chip implements the method of any one of the first to sixth aspects above.

[0053] In the thirteenth aspect, a communication system is provided, comprising: a first communication device, a second communication device and a third communication device; wherein the first communication device is used to implement the method of the first aspect or the second aspect, the second communication device is used to implement the method of the third aspect or the fourth aspect, and the third communication device is used to implement the method of the fifth aspect or the sixth aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 A schematic diagram of a multi-link device MLD provided in an embodiment of the present application;

[0055] Figure 2 A schematic diagram of an application scenario provided by an embodiment of the present application;

[0056] Figure 3 A flowchart of downlink data transmission provided in an embodiment of the present application;

[0057] Figure 4 A schematic diagram of processing downlink data provided in an embodiment of the present application;

[0058] Figure 5 A flowchart of uplink data transmission provided in an embodiment of the present application;

[0059] Figure 6 A schematic diagram of processing uplink data provided in an embodiment of the present application;

[0060] Figure 7a A flow chart of roaming switching provided in an embodiment of the present application;

[0061] Figure 7b and Figure 7c A schematic diagram of the message format provided for implementation of this application;

[0062] Figure 8 Another flowchart of roaming switching provided by an embodiment of the present application;

[0063] Fig. 9 , Fig.10 and Fig.11 A schematic diagram of a message format provided in an embodiment of the present application;

[0064] Fig.12 and Fig.13 A schematic diagram of the structure of the device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0065] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the embodiments of the present application will be further described in detail with reference to the accompanying drawings. The specific operation methods, functional descriptions, etc. in the method embodiments can also be applied to the device embodiments or system embodiments.

[0066] The embodiments of the present application can be applied to a wireless local area network (WLAN) system, and the embodiments of the present application can be applied to the Institute of Electrical and Electronics Engineers (IEEE) 802.11 series protocols adopted by the WLAN, such as 802.11be, 802.11bf, and future 802.11 protocols. The method provided by the embodiments of the present application can be implemented by a communication device in a wireless communication system or a chip or circuit applied to the communication device, and accordingly, the communication device supports communication using the IEEE802.11 series protocols. Although the embodiments of the present application are mainly described by taking the network deploying IEEE 802.11 as an example, it is easy for those skilled in the art to understand that the various aspects involved in the embodiments of the present application can be extended to other networks adopting various standards or protocols, for example, Bluetooth (BLUETOOTH), high performance wireless local area network (local area network, LAN) (high performance radio LAN, HIPERLAN) (a wireless standard similar to the IEEE 802.11 standard, mainly used in Europe) and wide area network (wide area network, WAN), WLAN, personal area network (personal area network, PAN) or other networks known now or developed later. The technical solutions of the embodiments of the present application can be applied to various cellular communication systems, for example, the fifth generation (5th generation, 5G) system, new radio (new radio, NR), the future sixth generation (6th generation, 6G) system, etc.

[0067] Multi-link technology can be used in the extremely high throughput (EHT) of the next generation wireless fidelity (WIFI) of IEEE802.11 to increase the transmission rate. A device with multi-link aggregation capability is called a multi-link device (MLD). In one design, MLD may mean that the device has multiple RF modules at the same time, each operating on a different frequency band / channel. When the channel spacing between two RF modules in a device is large enough, they can operate independently without interfering with each other. If any two links support sending on one link while receiving on the other link, the two links are said to support simultaneous transmit and receive (STR) capability. Otherwise, the two links are said to not support simultaneous transmit and receive capability, that is, the two links do not support simultaneous transmit and receive (non-STR).

[0068] MLD may include non-AP MLD and / or AP MLD, where non-AP MLD may also be called station MLD. Non-AP MLD and AP MLD may communicate with each other. Figure 1 As shown, the MLD (such as AP MLD or non-AP MLD) may include a physical layer (physical layer, PHY) (such as Figure 1 The physical layer can be used to process physical layer signals, and the MAC layer can be used to process MAC layer signals. Further, in the MAC layer, it can also be divided into a higher MAC (UMAC) layer (such as Figure 1 The high MAC shown in FIG. 1 and multiple low-MAC (LMAC) layers (such as Figure 1 As shown in FIG. 1 , FIG. 1A , FIG. 1B , and FIG. 1C . Figure 1As shown, the multiple APs included in the AP MLD are independent of each other in the low MAC layer and PHY, and share the high MAC layer. The multiple STAs included in the non-AP MLD are independent of each other in the low MAC layer and PHY, and share the high MAC layer. The high MAC layer is connected to multiple low MAC layers respectively, that is, the high MAC layer is shared by multiple links. Exemplarily, the high MAC layer mainly completes the allocation of sequence numbers (sequence number, SN) and packet numbers (packet number, PN) of MAC service data units (MAC service data unit, MSDU) and encryption and decryption operations. Exemplarily, the low MAC layer mainly completes the assembly of MAC protocol data units (MAC protocol data unit, MPDU) of each link, channel access, packet sending and reception confirmation and other operations.

[0069] exist Figure 1 In the AP MLD, the PHY#1 layer, the low MAC#1 layer and the high MAC layer can be regarded as AP#1, the PHY#2 layer, the low MAC#2 layer and the high MAC layer can be regarded as AP#2, ..., the PHY#n layer, the low MAC#n layer and the high MAC layer can be regarded as AP#n, that is, it can be understood that the AP MLD includes n AP entities. In non-AP MLD, the situation is similar, that is, the high MAC layer in non-AP MLD is also shared by multiple links, the PHY#1 layer, the low MAC#1 layer and the high MAC layer are regarded as STA#1, the PHY#2 layer, the low MAC#2 layer and the high MAC layer are regarded as STA#2, ..., the PHY#n layer, the low MAC#n layer and the high MAC layer are regarded as STA#n, that is, it can be understood that the non-AP MLD includes n STA entities. As Figure 1 As shown, PHY#1 of AP#1 in AP MLD and PHY#1 of STA#1 in non-AP MLD work on the same channel. AP#1 in AP MLD and STA#1 in non-AP MLD communicate via a link (such as Figure 1 The AP#2 in the AP MLD and the STA#2 in the non-AP MLD communicate via the link #1 shown in FIG. 1 ; the PHY#2 in the AP#2 in the AP MLD and the PHY#2 in the STA#2 in the non-AP MLD work on another identical channel, and the AP#2 in the AP MLD and the STA#2 in the non-AP MLD communicate via the link (as shown in FIG. Figure 1 The PHY#n of AP#n in the AP MLD and the PHY#n of STA#n in the non-AP MLD work on another identical channel, and the AP#n in the AP MLD and the STA#n in the non-AP MLD communicate via the link (as shown in FIG. Figure 1 The link #n) shown achieves communication.

[0070] In an embodiment of the present application, due to factors such as movement, the non-AP MLD may switch its associated AP MLD. For example, due to the movement of the non-AP MLD, it moves from the coverage of AP MLD1 to the coverage of AP MLD2. Therefore, it may be necessary to switch the AP MLD associated with the non-AP MLD. In one design, when switching, the non-AP MLD will first disconnect the old link with the current AP MLD, and then establish a new link with the target AP MLD. Due to the interruption of the transmission link, there is a risk of speed drop during the switching process. In the scheme of the embodiment of the present application, the non-AP MLD first establishes a second transmission link with the target AP MLD, and the non-AP MLD and the current AP MLD still transmit data. Later, at a certain point in time, the non-AP MLD disconnects the first transmission link with the current AP MLD. During the switching process, the non-AP MLD uses the multi-link capability to simultaneously transmit data with the current AP MLD and the target AP MLD. Since non-AP MLD always has a transmission link during the entire switching process, there is no situation where the transmission link is completely interrupted, which reduces the risk of speed drop during the switching process.

[0071] In the solution provided in the embodiment of the present application, during the switching or roaming process of the non-AP MLD, when dual-connection transmission is enabled, for downlink transmission, the current AP MLD needs to transparently transmit the encrypted data to the target AP MLD, and the target AP MLD directly submits the data to its low MAC for transmission after receiving the data; for uplink transmission, the target AP MLD transparently transmits the data received by the low MAC to the current AP MLD, and the current AP MLD directly submits the data to its high MAC for subsequent processing, such as decryption, etc. After the non-AP MLD switching is completed, or the roaming is completed, that is, when the transmission link of the non-AP MLD is switched from the current AP MLD to the target AP MLD, the target MLD can use the key negotiated with the target AP MLD (hereinafter referred to as the second key) for encryption and decryption.

[0072] like Figure 2 As shown, a communication system is provided, which includes a non-AP MLD and an AP MLD.

[0073] In the embodiment of the present application, the non-AP MLD may be a device with a wireless transceiver function. For example, the non-AP MLD may be a terminal device, a user equipment (UE), an access terminal, a subscriber unit (subscriberunit), a user station, a mobile station, a remote station, a remote terminal, a mobile device, a user terminal, a wireless communication device, a user agent or a user device. In a specific application, the non-AP MLD may be a cellular phone, a mobile phone, a tablet computer (pad), a wearable device, a smart point of sale (POS) machine, a customer-premises equipment (CPE), a computer with a wireless transceiver function, a virtual reality (VR) terminal, an augmented reality (AR) terminal, a terminal device in industrial control, a terminal device in self driving, a terminal device in remote medical, a terminal device in a smart grid, a terminal device in a smart city, a terminal in a smart home, etc.

[0074] In the present application example, non-AP MLD may include multiple links, each of which corresponds to a different STA entity. The multiple STA entities are independent of each other at the low MAC layer and PHY layer and share the high MAC layer. The multiple STA entities usually operate on different frequency bands or channels. Figure 2 In the example, non-AP MLD includes two STA entities, namely STA1 and STA2. Both STA1 and STA2 can work in the 2.4G frequency band and the 5G frequency band. At a certain moment, STA1 and STA2 work in different frequency bands.

[0075] AP MLD can be Figure 2 In the embodiment of the present application, the AP MLD is a device such as a wireless hub or router for providing wireless network access services, and can be used as an access point for a non-AP MLD to enter a wired Ethernet backbone.

[0076] Similar to non-AP MLD, AP MLD can include multiple links, each of which corresponds to a different AP entity. Multiple AP entities are independent of each other at the low MAC layer and PHY layer, and share the high MAC layer. The multiple AP entities usually work on different frequency bands or channels. Figure 2 In the example, APMLD1 and APMLD2 include two AP entities, respectively called AP1 and AP2. AP1 and AP2 work in different frequency bands, AP1 works in the 2.4 GHz frequency band, and AP2 works in the 5 GHz frequency band.

[0077] In one design, before handover or roaming, the non-AP MLD is associated with AP MLD1, and AP MLD1 is called the current APMLD. Figure 2 STA1 works in the 2.4 frequency band and establishes a link with AP1. STA2 works in the 5G frequency band and establishes a link with AP2.

[0078] Due to factors such as mobility, the non-AP MLD moves out of the coverage area of ​​the current AP MLD, AP MLD1, and enters the coverage area of ​​the target AP MLD (AP MLD2). During the handover or roaming process, the non-AP MLD has established transmission links with both the current AP MLD (AP MLD1) and the target AP MLD (AP MLD2). For details, see Figure 2 During the handover or roaming process, STA2 in non-AP MLD can disconnect the link with AP2 in the current AP MLD, and establish a link with AP1 in the target AP MLD. As mentioned above, the two STAs in non-AP MLD can work in the 2.4GHz or 5GHz frequency band. Figure 2 In the example, STA2 works in the 2.4 GHz frequency band and establishes a link with AP1 in the target STA MLD.

[0079] At a certain point in time, the non-AP MLD can be completely switched from the current AP MLD to the target AP MLD. Figure 2 In the example, STA1 in non-AP MLD will disconnect from the current AP MLD, and STA1 will establish a link with an AP in the target AP MLD. Figure 2 In the example, STA1 disconnects the link with the current AP MLD, STA1 works in the 5 GHz frequency band, and establishes a link with AP2 in the target APMLD.

[0080] like Figure 2 As shown, it can be seen that after the switching or roaming of the non-AP MLD is completed, the non-AP MLD accesses the target AP MLD. Specifically, STA1 of the non-AP MLD establishes a link with AP2 of the target AP MLD, and STA2 establishes a link with AP1 of the target AP MLD.

[0081] In one possible implementation, Figure 2 The communication system shown may also include other non-AP MLD and / or AP MLD devices, or other devices, etc., without limitation. For example, the communication system may also include: a distributed system (DS). In one implementation, the DS may be a system that interconnects multiple basic service sets (BSSs) and integrates a local area network to form an extended service set (ESS). In other words, the DS may construct an ESS, which includes multiple interconnected BSSs, or may be described as: the DS includes multiple interconnected BSSs, etc. The BSS is a basic component of the local area network (LAN) 802.11. The BSS is composed of STAs that form a certain connection within a certain coverage range. For example, an AP MLD may include multiple AP entities, each AP entity corresponds to a BSS, and the BSS corresponding to each AP entity may include at least one STA, and the multiple STAs are associated with the AP entity corresponding to the BSS. Before switching or roaming: During downlink data transmission, DS can forward downlink data to the current AP MLD, and the current AP MLD sends the downlink data to the non-AP MLD. During uplink data transmission, non-AP MLD can send uplink data to the current AP MLD, and the current AP MLD delivers the uplink data to DS. After switching or roaming: During downlink data transmission, DS can forward downlink data to the target AP MLD, and the target AP MLD sends the downlink data to the non-AP MLD. During uplink data transmission, non-AP MLD can send uplink data to the target AP MLD, and the target AP MLD delivers the uplink data to 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. The process of uplink data transmission and downlink data transmission can be seen in the following description.

[0082] In the embodiment of the present application, during the handover or roaming process, uplink data or downlink data transmission can be performed between the non-AP MLD and the target AP MLD. During the uplink data or downlink data transmission process, the data transmission between the non-AP MLD and the target AP MLD is encrypted and decrypted using a first key, and the first key is a key negotiated between the non-AP MLD and the current AP MLD.

[0083] In the following description, in downlink data transmission and uplink data transmission. There is a first transmission link between the non-AP MLD and the current AP MLD, and there is a second transmission link between the non-AP MLD and the target AP MLD. Before the non-AP MLD roams or switches, a first transmission link has been established between the non-AP MLD and the current AP MLD. During roaming or switching, a second transmission link can be established between the non-AP MLD and the target AP MLD. For the process of establishing the second transmission link, please refer to the following description. It should be noted that in the embodiment of the present application, the switching or roaming of the non-AP MLD can also be referred to as the BSS transfer of the non-AP MLD. The current AP MLD can be referred to as the AP MLD of the non-AP MLD before the BSS transfer, the target AP MLD can be referred to as the AP MLD of the non-AP MLD after the BSS transfer, and so on.

[0084]

Downlink data transmission

[0085] In one design, in downlink data transmission, the current AP MLD receives the third downlink data sent by the DS. After high MAC processing by the current AP MLD, the first downlink data is obtained, wherein the third downlink data is encrypted using the first key during encryption of the high MAC processing. The current AP MLD sends the first downlink data to the target AP MLD, and the target AP MLD performs low MAC layer and physical layer processing on the first downlink data to obtain second downlink data. The target AP MLD sends the second downlink data to the non-AP MLD.

[0086] like Figure 3 As shown, a process is provided, which can be applied to downlink data transmission, including:

[0087] Step 300: The current AP MLD receives the third downlink data sent by the DS.

[0088] In an embodiment of the present application, a mapping relationship between non-AP MLD and current AP MLD may be stored in DS, and a data path exists between DS and current AP MLD. When DS receives the third downlink data, the destination address of the third downlink data may be the address of non-AP MLD. DS may determine the association between non-AP MLD and current AP MLD based on the stored mapping relationship between non-AP MLD and current AP MLD. Therefore, DS forwards the third downlink data to the current AP MLD. Alternatively, the third downlink data is the downlink data to be sent by the current AP MLD. Therefore, step 300 is an implementation method and does not necessarily need to be executed.

[0089] Step 301: The current AP MLD encrypts the third downlink data using the first key to obtain the first downlink data, where the first key is the key negotiated between the current AP MLD and the non-AP MLD.

[0090] For example, the current AP MLD can perform high MAC layer processing on the third downlink data. During the high MAC layer processing: the current AP MLD will use the first key negotiated between the current AP MLD and the non-AP MLD to encrypt the third downlink data to obtain the first downlink data. At this time, the first downlink data can be said to be data encrypted using the first key, and the first key is the key negotiated between the current AP MLD and the non-AP MLD. In one implementation, the first key can be a pairwise transient key (PTK).

[0091] Step 302: The current AP MLD sends first downlink data to the target AP MLD.

[0092] In one design, step 302 may be described as: the current AP MLD transparently transmits the first downlink data to the target AP MLD. For example, the data transmission between the current AP MLD and the target AP MLD needs to be forwarded 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.

[0093] Step 303: The target AP MLD processes the first downlink data at the lower MAC layer and the physical layer to obtain second downlink data.

[0094] Step 304: The target AP MLD sends the second downlink data to the non-AP MLD.

[0095] 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 send the second downlink data to the non-AP MLD through the second transmission link. The non-AP MLD receives the second downlink data from the target AP MLD. Alternatively, it may be described as follows: the non-AP MLD receives the data from the current AP MLD through the target AP MLD.

[0096] For example, if Figure 4As shown, the current AP MLD can receive the third downlink data sent by the DS, and the DS can perform high MAC layer processing on the third downlink data to obtain the first downlink data. The processing of the high MAC layer includes but is not limited to at least one of the following: assigning a sequence number SN (SN assignment), assigning a packet sequence number PN (PN assignment), or encrypting the downlink data. In one design, the data input to the MAC layer can be called MSDU, and after being processed by the MAC layer, the data output by the MAC layer can be called MPDU. Therefore, the third downlink data can be called MSDU, the first downlink data can be called MPDU, and encrypting the downlink data at the MAC layer can be called MPDU encryption (MPDU encryption). The current AP MLD transparently transmits the first downlink data to the target AP MLD through the DS. The target AP MLD performs low MAC layer and physical layer processing on the first downlink data to obtain the second downlink data. As shown Figure 4 As shown, the processing of the lower MAC layer includes but is not limited to: creating a cyclic redundancy check (CRC) in the MPDU header (MPDU header CRC creation) and / or A-MPDU aggregation, etc. For example, in the process of creating the CRC in the MPDU header, the target AP MLD can add a CRC check bit to the header of the first downlink data. In the process of A-MPDU aggregation, the target AP MLD can aggregate multiple first downlink data together, etc. Figure 4 In the example, the interface between the low MAC layer and the physical layer of the current AP MLD or the target AP MLD can be called a physical layer service access point (SAP). The low MAC of the target AP MLD transmits the data processed by the low MAC to the physical layer through the physical layer SAP, and the second downlink data is obtained after being processed by the physical layer. Figure 4 In the example, the specific processing process of the physical layer is not explained in detail.

[0097] Step 305: The non-AP MLD decrypts the second downlink data using the first key.

[0098] In the scenario of the embodiment of the present application, the 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 the target AP MLD. The first transmission link and the second transmission link each have an independent physical layer and a low MAC layer, and the two transmission links share a high MAC layer. Specifically, when the non-AP MLD receives the second downlink data from the target AP MLD, it uses the physical layer and the low MAC layer corresponding to the non-AP MLD (for example, using the physical layer and the low MAC layer corresponding to the target AP MLD in the non-AP MLD) to process the second downlink data, and the processed data is submitted to the shared high MAC layer. During the processing of the high MAC layer, the non-AP MLD can use the first key to decrypt the second downlink data. Figure 4 As shown, the non-AP MLD includes two protocol stacks, namely, the physical layer and low MAC layer protocol stack corresponding to the current AP MLD, and the physical layer and low MAC layer protocol stack corresponding to the target AP MLD. The current AP MLD and the target AP MLD share the high-level protocol stack. When the non-AP MLD receives the second downlink data sent by the target AP MLD, it can first use the physical layer corresponding to the target AP MLD to process the second downlink data, and transmit the second downlink data to the low MAC layer corresponding to the target AP MLD through the physical layer SAP. The processing of the low MAC layer includes but is not limited to at least one of the following: A-MPDU de-aggregation, CRC validation in the MPDU header, address filter of address 1, or block ack scoring, etc. The non-AP MLD transmits the data processed by the lower MAC layer corresponding to the target AP MLD to the higher MAC layer. The processing of the higher MAC layer includes but is not limited to at least one of the following: block acknowledgment scoreboard, duplicate detection per SN, MPDU decryption, block acknowledgment buffering and reordering per SN, or replay detection per PN, etc.

[0099] It should be noted that in the embodiment of the present application, non-AP MLD has two transmission links, namely, 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 the end of roaming, the mapping relationship between non-AP MLD and current AP MLD is stored in DS. During downlink transmission, when DS receives downlink data with the destination address as non-AP MLD, it sends the downlink data to the current AP MLD according to the mapping relationship between non-AP MLD and current AP MLD. The specific processing for the current AP MLD includes but is not limited to: 1. The current AP MLD sends all downlink data to the non-AP MLD through the first transmission link. 2. The current AP MLD sends part of the downlink data to the non-AP MLD through the first transmission link. The other part of the downlink data is transparently transmitted to the target AP MLD through DS. The target AP MLD sends the other part of the downlink data to the non-AP MLD through the second transmission link. 3. The current APMLD transparently transmits all the downlink data to the target AP MLD through DS. The target AP MLD sends all downlink data to the non-AP MLD through the second transmission link. Figure 3 In the process of , the focus is on: when the current AP MLD receives the downlink data from the DS, it transparently transmits the downlink data to the target AP MLD through the DS. The target AP MLD sends the downlink data to the non-APMLD. In a possible implementation, Figure 3 In the process, the current AP MLD can transparently transmit all downlink data received from the DS to the target AP MLD through the DS. Figure 3In the process, the current AP MLD sends a part of the downlink data received from the DS to the non-AP MLD through the first transmission link. The current AP MLD transparently transmits another part of the downlink data received from the DS to the target AP MLD through the DS. The target AP MLD sends another part of the downlink data to the non-AP MLD through the second transmission link. The above-mentioned division of the downlink data into two parts and sending them to the non-AP MLD through different transmission links can improve the transmission speed of the downlink data. Even in another scenario, the current AP MLD copies the downlink data received from the DS. One copy is transmitted to the non-AP MLD through the first transmission link. The other copy is transparently transmitted to the target AP MLD through the DS. The target AP MLD sends the downlink data to the non-AP MLD through the second transmission link, etc., which can improve the transmission reliability of the downlink data. Even the current AP MLD can send all or part of its downlink data to be sent to the target AP MLD, and the target AP MLD sends the received downlink data to the non-AP MLD. In the embodiment of the present application, the source of the downlink data of the current AP MLD is not limited, and the focus is on: when the current AP MLD sends downlink data to the target AP MLD, the current AP MLD and the target AP MLD each process the downlink data.

[0100]

Uplink data transmission

[0101] In one design, in uplink data transmission, 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 the end of roaming, the DS side stores the mapping relationship between the current AP MDL and the non-AP MLD. In order for the DS to correctly process the uplink data, the uplink data needs to be delivered to the current AP MLD, and then the current AP MLD delivers the uplink data to the DS. The non-AP MLD delivers the uplink data to the current AP MLD, including but not limited to the following methods:

[0102] 1. The non-AP MLD delivers the uplink data to the current AP MLD through the first transmission link.

[0103] 2. The non-AP MLD delivers part of the uplink data to the current AP MLD. The non-AP MLD delivers another part of the uplink data to the target AP MLD. The target AP MLD transparently transmits the other part of the uplink data to the current AP MLD through the DS. Dividing the uplink data into two parts and transmitting them to the current AP MLD through different links can increase the transmission rate of the uplink data.

[0104] 3. The non-AP MLD delivers all uplink data to the target AP MLD. The target AP MLD transparently transmits all uplink data to the current AP MLD through the DS.

[0105] 4. Non-AP MLD can copy the uplink data into two copies, one of which is sent directly to the current AP MLD through the first transmission link. The other is sent to the target AP MLD through the second transmission link. The target AP MLD transparently transmits the uplink data to the current AP MLD through DS. Transmitting the same uplink data through two transmission links can improve the transmission reliability of uplink data.

[0106] In the above-mentioned methods 2, 3 and 4, the following process is involved: the non-AP MLD sends the uplink data to the target AP MLD, and the target AP MLD transparently transmits the uplink data to the current AP MLD through the DS. In a possible implementation, the above-mentioned methods 1 to 4 are only for illustrative purposes and are not intended to limit the scenario of uplink data transmission in this application.

[0107] In the uplink data transmission process provided in the embodiment of the present application, when the non-AP MLD sends uplink data to the target AP MLD, the non-AP MLD uses the first key negotiated between the non-AP MLD and the current AP MLD to encrypt the uplink data. Figure 5 As shown, a process is provided, which may be applicable to uplink data transmission, including:

[0108] Step 500: The non-AP MLD encrypts the uplink data to be transmitted using a first key to determine first uplink data, where the first key is a key negotiated between the non-AP MLD and the current AP MLD.

[0109] In one design, the non-AP MLD processes the uplink data to be transmitted in the shared high MAC layer, the exclusive low MAC layer, and the physical layer in sequence. The high MAC layer processing at least includes: using the first key negotiated between the non-AP MLD and the current AP MLD to encrypt the uplink data to be transmitted. Figure 6As shown, the processing of the high MAC layer of the non-AP MLD includes but is not limited to at least one of the following: assigning a sequence number SN (SN assignment), assigning a packet sequence number PN (PN assignment), or MPDU encryption (MPDU encryption), etc. Among them, in MPDU encryption: the non-AP MLD uses the first key negotiated with the current AP MLD to encrypt the uplink data. Furthermore, the non-AP MLD includes two transmission links, each of which exclusively occupies the low MAC layer and the physical layer, that is, the first transmission link and the second transmission link correspond to independent low MAC layers and physical layers, respectively. In an embodiment of the present application, the non-AP MLD may use the low MAC layer and the physical layer corresponding to the second transmission link corresponding to the target AP MLD to process the uplink data. Exemplarily, as Figure 6 As shown, the processing of the lower MAC layer corresponding to the target AP MLD includes but is not limited to: creating a CRC in the MPDU header (MPDU header CRC creation) and / or A-MPDU aggregation, etc. Figure 6 In the process, the lower MAC layer of the target AP MLD delivers the uplink data to the physical layer of the target AP MLD through the physical layer SAP, and continues to process the uplink data at the physical layer. After the processing at the physical layer, the uplink data is sent to the target AP MLD through the second transmission link.

[0110] Step 501: The non-AP MLD sends first uplink data to the target AP MLD.

[0111] Step 502: The target AP MLD processes the first uplink data at the physical layer and the lower MAC layer to determine the second uplink data.

[0112] like Figure 6 As shown, the lower MAC layer processing of the target AP MLD includes but is not limited to at least one of the following: A-MPDU de-aggregation, CRC validation in the MPDU header, address filter of address 1, or block acknowledgment scoreboard, etc.

[0113] Step 503: The target AP MLD sends second uplink data to the current AP MLD.

[0114] Correspondingly, the current AP MLD receives the second uplink data from the target AP MLD, or can be described as: the current AP MLD receives the uplink data from the non-AP MLD through the target AP MLD, or can be described as: the non-AP MLD sends the second uplink data to the current AP MLD through the target AP MLD, etc.

[0115] Step 504: the current AP MLD performs high MAC layer processing on the second uplink data, and decrypts the second uplink data using the first key to determine the third uplink data.

[0116] like Figure 6 As shown, the high MAC layer processing of the current AP MLD includes but is not limited to at least one of the following: block acknowledgment scoreboard (blcok ack scoredoarding), duplicate detection per SN (duplicate detection per SN), MPDU decryption (MPDU decryption), block acknowledgment buffering and SN reordering (blcok ack buffering and reordering per SN), or replay detection per PN (replay detection per PN), etc.

[0117] It can be seen from the above steps 502 to 504 that when the target AP MLD receives the uplink data from the non-AP MLD, the target AP MLD processes the received uplink data at the physical layer and the low MAC layer, bypasses the high MAC processing of the target AP MLD, and sends the uplink data processed by the low MAC layer to the current AP MLD. After receiving the uplink data, the current AP MLD processes the uplink data at the high MAC layer.

[0118] Step 505: The current AP MLD sends the third uplink data to the DS.

[0119] In one design, the current AP MLD may send the third uplink data to the DS, and the DS may process or apply the third uplink data. Alternatively, the third uplink data may be sent to the current AP MLD, and the current AP MLD may directly process or apply the third uplink data. 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.

[0120] The embodiment of the present application also provides a process for establishing a second transmission link between the non-AP MLD and the target AP MLD. For example, a first transmission link is established between the non-AP MLD and the current AP MLD. In one implementation, the first transmission link can be considered as a data connection between the non-AP MLD and the current AP MLD. There is a data path between the current APMLD and the DS, and the DS stores a mapping relationship between the non-AP MLD and the current AP MLD. The current AP MLD finds through measurement that the link quality of the first transmission link between the non-AP MLD and the current AP MLD has deteriorated, for example, the link quality of the first transmission link is less than or equal to a threshold, etc. At this time, the current AP MLD can allow the non-AP MLD to perform beacon measurement. The current AP MLD recommends the AP MLD to which it switches to the non-AP MLD based on the beacon measurement result reported by the non-AP MLD. The non-AP MLD selects an AP MLD from the recommended AP MLDs, and the AP MLD serves as the target AP MLD. In one implementation, the non-AP MLD reports its selected target AP MLD to the current AP MLD. In one implementation, the current APMLD may send a seventh request to the non-AP MLD, the seventh request also including second indication information, the second indication information instructing the non-AP MLD to retain the BA session information and / or context information of the non-AP MLD, and cache the data not sent by the non-AP MLD. When the non-AP MLD receives the second indication information, it may retain the BA session information and / or context information in the subsequent tentative connection process. In one implementation, the non-AP MLD may send a seventh response to the current AP MLD, the seventh response being a response to the seventh request. In one implementation, the seventh request may be a BSS transition management (BTM) request frame, and the seventh response may be a BTM response frame.

[0121]

Tentative association

[0122] The non-AP MLD can establish a tentative association with the target AP MLD through an affiliated STA. During the tentative association process, the non-AP MLD can establish a second transmission link with the target AP MLD. Furthermore, the transmission capability parameters of the two parties (for example, the transmission bandwidth and maximum number of streams between the two parties, etc.), the key information of the two parties (such as PTK, group temporal key (GTK), integrity group temporal key (IGTK) and beacon integrity group temporal key (BIGTK), etc.), and the resource allocation information of the two parties (such as BA session, restricted target wakeup time (r-TWT) establishment, etc.) can also be negotiated.

[0123] In one design, the non-AP MLD may send a first request to the target AP MLD, where 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, where the first response is a response to the first request. For example, the non-AP MLD may send a first request to the target AP MLD, where 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 MLD, where the first response is used to indicate that the target AP MLD agrees to establish the second transmission link and indicates at least one of the transmission capability parameters, key information, or resource allocation information of the two. The target AP MLD sends a first response to the non-AP MLD, where the first response may include at least one of the transmission capability parameters, key information, or resource allocation information of the two that have been negotiated by the two.

[0124] In one implementation, the first request may be a reassociation request frame and carry tentative association indication information, and the reassociation request frame carrying the tentative association indication information is used for the non-AP MLD to request a tentative association with the target AP MLD. The first response may be a reassociation response frame and carry the tentative association indication information, and the reassociation response frame carrying the tentative association indication information is used to implement a tentative association between the non-AP MLD and the target AP MLD. During the tentative association process, the non-AP MLD and the target AP MLD may establish a second transmission link and negotiate various parameters.

[0125] In another implementation, the first request may be a newly defined action frame and carry the same content as a reassociation request frame, and the first request is used for the non-AP MLD to request a tentative association with the target AP MLD. The first response may be a newly defined action frame and carry the same content as a reassociation response frame, and the first response is used to implement a tentative association between the non-AP MLD and the target AP MLD. During the tentative association process, the non-AP MLD and the target AP MLD may establish a second transmission link and negotiate various parameters.

[0126] It should be noted that during the tentative association process: the target AP MLD does not refresh the mapping relationship between the non-APMLD and the current AP MLD stored on the DS side. Before sending the first request (such as the reassociation request frame in the previous text), the non-AP MLD will not delete the first key negotiated with the current AP MLD, will not clear the sending buffer and the receiving buffer, etc. The non-AP MLD still maintains the first transmission link with the current AP MLD. Through the first transmission link, the non-APP MLD and the current APMLD can still transmit uplink data and / or downlink data.

[0127] In one implementation, the first request may include indication information for enabling dual-link transmission of the non-AP MLD, wherein the dual-link includes a first transmission link between the non-AP MLD and the current AP MLD, and a second transmission link between the non-AP MLD and the target AP MLD, etc. After the target AP MLD obtains the above indication information and successfully establishes the second transmission link, the target AP MLD will initiate dual-link transmission negotiation with the current AP MLD to enable dual-link transmission.

[0128]

Dual link transmission

[0129] Since data needs to be transmitted between the current AP MLD and the target AP MLD during dual-link roaming, the target AP MLD can send a second request to the current AP MLD when it obtains the indication of the non-AP MLD to start dual-link transmission through the first request. The second request is used to request to start the dual-link transmission of the non-AP MLD. In the downlink transmission of the dual link, the current AP MLD can transparently transmit the downlink encrypted data of the non-AP MLD to the target AP MLD, and then the target AP MLD sends the downlink data to the non-AP MLD. In the uplink transmission of the dual link, the target AP MLD can transparently transmit the uplink data received from the non-AP MLD to the current AP MLD, and the current AP MLD decrypts the uplink data and sends the decrypted uplink data to the DS, etc. For the specific process, please refer to [Uplink Data Transmission] and [Downlink Data Transmission] above. In one implementation, the current AP MLD can send a second response to the target AP MLD, and the second response is a response to the second request. For example, the second response may include indication information of whether the current AP MLD agrees to start the dual-link transmission.

[0130] In one design, dual-link transmission during roaming may be described as roaming transmission based on a dual-active protocol stack (DAPS). Roaming transmission based on DAPS may refer to a non-AP MLD with multi-link simultaneous transmission and reception, which can simultaneously perform uplink and / or downlink transmission with a current AP MLD and a target AP MLD during roaming. Exemplarily, the second request may be a DAPS enable request, and the second response may be a DAPS enable response.

[0131] In one design, the target AP MLD may send the maximum MAC layer MPDU length supported by the target AP MLD, and / or the maximum number of MAC layer MSDUs that the target AP MLD allows to be aggregated, etc. to the current AP MLD. Afterwards, the data sent by the current AP MLD to the target AP MLD needs to meet the above requirements. In one implementation, the above second request may include: the maximum MAC layer MPDU length supported by the target AP MLD, and / or the maximum number of MAC layer MSDUs that the target AP MLD allows to be aggregated, etc. In one implementation, the target AP MLD may also send the MLD address of the corresponding non-AP MLD to the current AP MLD, etc.

[0132] Similarly, the current AP MLD may also send the maximum MAC layer MPDU length supported by the current AP MLD, and / or the maximum number of MAC layer MSDUs allowed to be aggregated by the current AP MLD, etc. to the target AP MLD. Afterwards, the data sent by the target AP MLD to the current APMLD needs to meet the above requirements. In an embodiment of the present application, there is no restriction on the manner in which the current AP MLD sends the maximum MAC layer MPDU length supported by the current AP MLD, and / or the maximum number of MAC layer MSDUs allowed to be aggregated by the current AP MLD, etc. to the target AP MLD.

[0133] In a possible implementation, the data transmission between the target AP MLD and the current AP MLD can be forwarded by DS. In the embodiment of the present application, it is not limited whether the DS performs relevant processing and / or operation on the data during the process of forwarding the data. If the DS does not perform any relevant operation or processing on the data, it can be called transparent transmission of the DS. In one design: the current APMLD can encapsulate the data in a special frame or message and transparently transmit it to the target AP MLD through the DS. In a possible implementation, "transparent transmission" in the relevant description of the embodiment of the present application can also be replaced with: sending or forwarding and other related descriptions. If the DS performs corresponding operations and / or processing on the received data during the process of data forwarding, it is also within the protection scope of the embodiment of the present application. Alternatively, data can be directly transmitted between the target AP MLD and the current AP MLD without limitation.

[0134]

Data path switching

[0135] The non-AP MLD can trigger the switching of the data path, for example, switching the transmission path of the non-AP MLD from the current AP MLD to the target AP MLD. In one possible implementation, after the data path is switched, the non-AP MLD will use the second key negotiated with the target AP MLD to encrypt and decrypt the uplink data and / or downlink data. In one implementation, the second key can be a PTK.

[0136] In one implementation, in an embodiment of the present application, the conditions for triggering data path switching by non-AP MLD are not limited. For example, non-AP MLD can trigger data path switching when a first condition is met. The first condition includes but is not limited to: the link quality of the optimal link of the target AP MLD is higher than the link quality of the optimal link of the current AP MLD, etc.

[0137] It should be noted that during roaming, the non-AP MLD uses the first transmission link and the second transmission link to perform data transmission at the same time. At the end of roaming, the non-AP MLD can perform data path switching. In one description, the non-AP MLD disconnects the first transmission link during the data path switching process and completely uses the second transmission link for data transmission. Or, in another description, through the above Figure 2 From the example, we can see that in dual-link transmission, the non-AP MLD uses different STA entities to establish transmission links with the current AP MLD and the target AP MLD respectively. Figure 2 In the description, during the roaming process: STA1 of non-AP STA establishes a first transmission link with the current AP MLD, and STA2 of non-AP MLD establishes a second transmission link with the target AP MLD. During the data path switching process, STA1 disconnects the first transmission link with the current AP MLD, and another transmission link is established between STA1 and the target AP MLD.

[0138] In one design, during the process of non-AP MLD triggering path switching: the non-AP MLD may send a third request to the target AP MLD, and the third request is used to request triggering path switching of the non-AP MLD (for example, the switching may be a data path switching). In one implementation, the target AP MLD may send a third response to the non-AP MLD, and the third response may be a response to the third request. For example, the third response may include indication information of whether the path switching is agreed. If the target AP MLD agrees to the path switching of the non-AP MLD, the target AP MLD may send a fourth request to the DS, and 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 one implementation, the DS may send a fourth response to the target AP MLD, and the fourth response may be a response to the fourth request. In one implementation, the fourth response may include indication information of whether the DS agrees to update the mapping relationship. Alternatively: the target AP MLD may send an uplink data packet to the DS via a MAC SAP. The DS automatically updates the stored mapping relationship according to the information that the uplink data packet can carry the non-AP MLD.

[0139] In one implementation, the third request is a STA-to-AP mapping request frame, and the third response is a STA-to-AP mapping response. The fourth request is a DS-STA-notify request for updating or adding, and the fourth response may be a DS-STA-notify response.

[0140] Further, after the target AP MLD receives the third request and before the target AP MLD sends the fourth request to the DS, it also includes: the target AP MLD sends a context transfer request (context transfer request) to the current AP MLD; the target AP MLD receives a context transfer response (context transfer response) sent by the current AP MLD, and the context transfer response includes the context information of the non-AP MLD.

[0141] In one implementation, the context transfer response further includes at least one of the following: a block determination protocol of a traffic identifier (TID), a window start position of a send buffer of the TID, a window size of a send buffer of the TID, a window start position of a scoreboard of an uplink receiving end, a window size of the scoreboard of the uplink receiving end, a window start position of a receive reordering buffer, a window size of the receive reordering buffer, a maximum packet sequence number PN value currently received, or an uplink replay counter.

[0142] In one design: the target AP MLD receives a third request from the non-AP MLD, and 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 period of time, and then sends a fourth request to the DS to refresh the mapping relationship stored on the DS side. This ensures that the uplink delivery is not disordered. The reason is as follows: before refreshing the mapping relationship stored on the DS side, the uplink data is delivered to the DS through the current AP MLD. At the moment when the transmission path of the non-AP MLD is switched from the first transmission path to the second transmission path, that is, when the target AP MLD receives the context transfer response of the current AP MLD, it is possible that the uplink data delivered to the DS by the current AP MLD has not been processed. Therefore, in an embodiment of the present application, when the target AP MLD receives the context transfer response of the current AP MLD, it waits for a period of time. At this time, when the DS has processed the uplink data of the current AP MLD, it sends the fourth request to refresh the mapping relationship to the DS. Alternatively, before the current AP MLD sends the context transfer response, it needs to ensure that all its uplink data has been successfully delivered to the DS. For example, in one implementation, after the current AP MLD sends the sixth request to the DS for deleting the mapping relationship between the non-AP MLD and the current AP MLD, the current AP MLD sends the context transfer response to the target AP MLD. For the sixth request, please refer to the following description.

[0143] In one implementation, when the non-AP MLD determines to trigger the path switching, the non-AP MLD may also send a fifth request to the current AP MLD, and the current AP MLD receives the fifth request sent by the non-AP MLD, wherein the fifth request is used to request to cut off the association between the non-AP MLD and the current AP MLD. Upon receiving the fifth request, the current AP MLD may disconnect the first transmission link with the non-AP MLD. In one implementation, the fifth request includes first indication information, wherein the first indication information indicates that the current AP MLD retains the BA information and / or context information of the non-AP MLD and caches the data not sent by the non-AP MLD. After the current AP MLD receives the fifth request, the current AP MLD sends a sixth request to the DS, wherein the sixth request is used to request to delete the mapping relationship between the non-AP MLD and the current AP MLD stored in the DS. Upon receiving the sixth request, the DS may delete the mapping relationship between the non-AP MLD and the current AP MLD stored in it. In one implementation, the current AP MLD may actively trigger the non-AP MLD to perform BSS transfer. For example, the current AP MLD actively triggers the non-AP MLD to switch to the target AP MLD. At this time, the current AP MLD may send a fifth request to the non-AP MLD. The fifth request is used to cut off the association between the current AP MLD and the non-AP MLD.

[0144] In one implementation, the fifth request may be a disassociation frame, and the sixth request may be a DS-STA-NOTIFY.request for deletion.

[0145] In one design, the non-AP MLD may not send the fifth request to the current AP MLD. At this time, after the current AP MLD receives the context transfer request from the target AP MLD and does not receive the fifth request sent by the non-AP MLD, the current AP MLD may stop submitting uplink data to the DS, and the current AP MLD sends the sixth request to the DS, which is used to request the deletion of the mapping relationship between the non-AP MLD and the current AP MLD stored in the DS. Afterwards, the current AP MLD sends a context transfer response to the target AP MLD.

[0146] It should be noted that, in the above description: the target AP MLD can send a fourth request to the DS, and the fourth request is used to request the DS to update the mapping relationship between the stored non-AP MLD and the current AP MLD to: the mapping relationship between the non-AP MLD and the target AP MLD. And in the above description: the current AP MLD can send a sixth request to the DS, and the sixth request is used to request to delete the mapping relationship between the non-AP MLD and the current AP MLD stored in the DS. In one design, the DS first executes: receiving the sixth request, deleting the mapping relationship between the non-AP MLD and the current AP MLD stored in it. Afterwards, the DS receives the fourth request, and the fourth request adds to its storage: the mapping relationship between the non-AP MLD and the target AP MLD. In other words, the updated mapping relationship in the fourth request in the above text can also be expressed as: adding a 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 therein, for example, replacing the mapping relationship stored therein between the non-AP MLD and the current AP MLD with the mapping relationship between the non-AP MLD and the target AP MLD. At this point, the current AP MLD may no longer send the sixth request for deleting the mapping relationship to the AP MLD.

[0147] On the DS side, after receiving the fourth request from the target AP MLD, the DS may switch the data path. For example, the DS deletes the data path between the non-AP MLD and the current AP MLD, and the DS adds the data path between the non-AP MLD and the target AP MLD. After the current AP MLD successfully sends the context transfer response, the current AP MLD may release the context of the non-AP MLD.

[0148] In an embodiment of the present application, the current AP MLD also needs to send the downlink data and / or uplink data that meet the following conditions to the target AP MLD. For example, in one design, the current AP MLD may send the downlink data and / or uplink data described below to the target AP MLD upon receiving a context transfer request from the target AP MLD. The downlink data and / or uplink data described below may be carried in a context transfer response. Alternatively, the current AP MLD may send the uplink data and / or downlink data described below to the target AP MLD before or after the current AP MLD sends a context transfer response to the target AP MLD, without limitation.

[0149] For example, for downlink data transmission, the current AP MLD needs to forward the (unencrypted) downlink data to the target APMLD and carry an end identifier in the last downlink data. In one implementation, the downlink data may be an MSDU or an MPDU. For downlink data in MPDU format, the more data field in the MPDU header may be reused. For example, when the MPDU is the last downlink data, the more data field is set to a first value, otherwise the more data field is set to a second value. In one implementation, the first value may be 0 and the second value may be 1. When the target AP MLD receives the downlink data forwarded by the current AP MLD, it encrypts the downlink data using a second key and then sends the downlink data to the non-AP MLD.

[0150] For example, for uplink data transmission, the current AP MLD can forward the high MAC layer processed (for example, decrypted MSDU or MPDU) in the uplink receive buffer to the target AP MLD and store it in the receive reordering buffer. Then the target AP MLD sends the received complete and continuous uplink data to the DS in sequence.

[0151] In one design, when switching, the non-AP MLD will first disconnect the old link with the current AP MLD, and then establish a new link with the target AP MLD. Before the non-AP MLD establishes a new link with the target AP MLD, the non-AP will clear the sending buffer and the receiving buffer, thereby causing packet loss. The receiving buffer is used to store discontinuous data received by the non-AP MLD, and the sending buffer is used to store data that the non-AP MLD has not sent or has sent but has not been confirmed by the receiving end. In the scheme of the 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 will not clear the sending buffer and the receiving buffer, and the non-AP MLD and the current AP MLD will still transmit data, thereby avoiding packet loss. Afterwards, at a certain point in time, the non-AP MLD disconnects the first transmission link with the current AP MLD again, and transfers the transmission session or block acknowledgment (BA) session to the target AP MLD. During the handover process, the non-AP MLD uses the multi-link capability to simultaneously communicate data with the current AP MLD and the target AP MLD, reducing the risk of rate drop during the handover process.

[0152] [Example 1]

[0153] In the embodiment of the present application, a second transmission link is directly established between the non-AP MLD and the target AP. The first request and / or the third request in the foregoing text are transmitted via the air interface between the non-AP MLD and the target AP MLD. Figure 7a As shown in FIG. 1 , a process is provided. It should be noted that when executing Figure 7a Before the process: There is a first transmission link between the non-AP MLD and the current AP MLD. For example, there is a data connection between the non-AP MLD and the current AP MLD. There is a data path between the current AP MLD and the DS, and the DS stores the mapping relationship between the non-AP MLD and the current AP MLD. Figure 7a As shown, the process includes:

[0154] Step 701: the current AP MLD finds that the link quality of the non-AP MLD deteriorates, and the current AP MLD sends a beacon measurement request to the non-AP MLD.

[0155] Step 702: The non-AP MLD performs beacon measurement and feeds back a beacon measurement report to the current AP MLD.

[0156] Step 703: The current AP MLD recommends the non-AP MLD to switch to the neighboring 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 includes indication information of 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.

[0157] In one implementation, the BTM request frame includes second indication information, and the second indication information is used to instruct the non-APMLD to retain the BA information and / or context information of the non-AP MLD and cache the data not sent by the non-AP MLD. When the non-AP MLD obtains the second indication information, it can enable dual-link roaming based on DAPS.

[0158] In one implementation, before the current AP MLD sends the BTM request frame to the non-AP MLD, the non-AP MLD may also send a BTM inquiry frame to the current AP MLD. After receiving the BTM inquiry frame, the current AP MLD sends a BTM request frame to the current AP MLD.

[0159] Step 704: the non-AP MLD sends a BTM response frame to the current AP MLD. The BTM response frame includes the target AP MLD selected by the non-AP MLD.

[0160] Step 705: The non-AP MLD performs a tentative association with the target AP MLD. During the tentative association process, the following processes may be implemented: establishing a second transmission link between the target AP MLD and the non-AP MLD, such as the bandwidth of the second transmission link and the maximum number of streams supported; establishing a BA session; negotiating a key, the negotiated key including a second key for communication between the two parties, etc.

[0161] In one implementation, a tentative association can be achieved between the non-AP MLD and the target AP MLD through a reassociation request frame and a reassociation response frame. For the reassociation request frame and the reassociation response frame, please refer to the description of the first request and the first response in the previous text. In a possible implementation, during the tentative association process, the mapping relationship between the non-APMLD and the AP MLD stored on the DS side is not refreshed. At this time, the mapping relationship between the non-AP MLD and the current AP MLD is stored on the DS side. At this time, when the DS receives the downlink data of the non-AP MLD, it will be submitted to the current AP MLD.

[0162] Step 706: After the non-AP MLD completes the tentative association with the target AP MLD, the target AP MLD and the current AP MLD can enable DAPS roaming through the interaction of DAPS enablement request and DAPS enablement response.

[0163] For the DAPS enable request and DAPS use response, please refer to the description of the second request and the second response in the previous text.

[0164] Step 707: non-AP MLD triggers path switching. Non-AP MLD sends a STA and AP mapping request frame to the target AP MLD. The STA and AP request frame can be used to request the target AP MLD to perform path switching. For the STA and AP mapping request frame, please refer to the third request in the above text.

[0165] Step 708: The target AP MLD sends a context transfer request to the current AP MLD.

[0166] Step 709: The current AP MLD sends a context transfer response to the target AP MLD. For the content carried in the context transfer response, please refer to the above description.

[0167] Step 7010: The target AP MLD sends a DS-STA-Notify Request to the DS.

[0168] When the DS receives the above DS-STA-notify request, it can update the 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 disconnects the data path with the current AP MLD and establishes a data path with the target AP MLD. For the DS-STA-notify request, please refer to the description of the fourth request in the previous text.

[0169] Step 7011: The current AP MLD deletes the context of the non-AP MLD.

[0170] After step 7011, the transmission path of the non-AP MLD is switched from the first transmission path to the second transmission path.

[0171] The non-AP MLD and the target AP MLD may use the negotiated second key to encrypt and decrypt the uplink data and / or the downlink data.

[0172] In one implementation, in step 707, when the non-AP MLD determines to trigger the path switching, the non-AP MLD further includes: the non-AP MLD sends a disassociation frame to the current AP MLD. The disassociation frame can refer to the fifth request in the above text. The current AP MLD can 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 stored in it.

[0173] In the embodiment of the present application, the transmission between the current AP MLD and the target AP MLD is transparently transmitted through the DS. In the embodiment of the present application, the transmission between the current AP MLD and the target AP MLD includes but is not limited to the aforementioned: DAPS enable request, DAPS enable response, context transfer request, or context transfer response. In addition, uplink data and / or downlink data can also be transmitted between the current AP MLD and the target MLD. For details, please refer to the description of [Uplink Data Transmission] and [Downlink Data Transmission] in the previous text.

[0174] In one design, the following frame format may be used for information and / or data transmitted between the AP MLD and the target AP MLD. Figure 7b As shown, the frame format includes at least one of the following fields:

[0175] Destination MAC address: can carry a 48-bit MAC address.

[0176] Source MAC address: can carry a 48-bit MAC address.

[0177] Length field;

[0178] The logical link control (LLC) field includes: the destination service access point (DSAP) address (this field is fixed to AA), the destination service access point (SSAP) address (this field is fixed to AA), and the control field (fixed to 0x03).

[0179] The subnetwork access protocol (SNAP) field includes an organizationally unique identifier field and an ether type field.

[0180] Payload type field: This field can be set to one or more preset values ​​depending on the payload.

[0181] Payload field: For example, the payload field may carry the DAPS enable request, DAPS enable response, context transfer request, context transfer response, or uplink / downlink data that needs to be transparently transmitted, etc. The payload field may carry an MPDU that complies with the tunneling 802.11 protocol, etc.

[0182] It should be noted that when transparently transmitting uplink / downlink data between the current AP MLD and the target AP MLD, the information carried in the payload field can be constructed by referring to the additional authentication data (AAD) of the cipher-block chaining message authentication code protocol (CCMP), and carries the CCMP header and the encrypted frame body. In one design, Figure 7cAs shown, the payload field includes at least one of the following fields: frame control, address 1, address 2, address 3, sequence control, quality of service (QoS) control, encryption protocol header (CCMP header), or frame body, etc.

[0183] In one implementation, the payload field may further include at least one of the following fields: retry, power management, data field, + high throughput control (HTC) field, or QoS field other than the TID field, etc. Further, when the payload field carries the above fields, the specific values ​​of the above fields may be set to empty.

[0184] Through the first embodiment, during the non-AP MLD switching or roaming process, the non-AP MLD uses the multi-link capability to establish a dual link with the current AP MLD and the target AP MLD, and realizes the simultaneous use of the current AP MLD and the target AP MLD for data transmission, thereby improving the transmission rate and transmission reliability during roaming. Furthermore, since during the roaming process, the non-AP MLD does not disconnect the first transmission link with the current AP MLD, and does not clear its sending buffer and receiving buffer, the probability of packet loss and / or interruption during roaming can be reduced.

[0185] [Example 2]

[0186] In the embodiment of the present application, the second transmission link between the non-AP MLD and the target AP is established through the current AP MLD and the DS. The first request and / or the third request in the foregoing text are transmitted through the current AP MLD and the DS. For example, the non-AP MLD can send the first request and / or the third request to the current AP MLD, and the current AP MLD sends the first request and / or the third request to the target AP MLD through transparent transmission of the DS.

[0187] For non-AP MLD, there is another important device type, enhanced multi-link single radio (EMLSR) non-AP MLD. In one design, EMLSR non-APMLD refers to a device with multiple receiving radio chains that can monitor multiple links at the same time. When receiving the initial control frame sent by AP MLD, the radio chains of other links in the EMLSR link set can be switched to the corresponding link that receives the initial control frame to increase the number of transceiver streams. That is, at any time, EMLSR non-AP MLD can only select one link for data transmission and reception. Compared with non-AP MLD with multiple radios, eMLSR non-AP MLD has only one fully functional transceiver, and the rest are low-cost machines with limited functions (because they can only receive specific initial control frames), so the cost is much lower, but the performance is much lower than that of non-AP MLD with multiple radios. Since EMLSR non-AP MLD can only transmit and receive data on one link. When it adopts the solution in the first embodiment to perform a tentative association with the target AP MLD, it needs to jump to the corresponding channel of the target AP MLD to perform a tentative association operation, which will cause the data transmission between it and the current AP MLD to be interrupted, seriously affecting its roaming performance. Therefore, the second embodiment proposes a solution that can further improve the roaming performance of non-AP MLD, especially improve the roaming performance of non-AP MLD and EMLSR non-AP MLD of a single radio link.

[0188] like Figure 8 As shown in the figure, a process is provided. Figure 8 Before the process, a first transmission link is established between the non-AP MLD and the current AP MLD. The first transmission link is also called the data connection between the current AP MLD and the non-AP MLD. There is a data path between the DS and the current AP MLD. The DS stores the mapping relationship between the non-AP MLD and the current AP MLD, such as Figure 8 As shown, the process includes:

[0189] Step 801: the current AP MLD finds that the link quality of the non-AP MLD deteriorates, and the current AP MLD sends a beacon measurement request to the non-AP MLD.

[0190] Step 802: The non-AP MLD performs beacon measurement and feeds back a beacon measurement report to the current AP MLD.

[0191] Step 803: The current AP MLD recommends the non-AP MLD to switch to the neighboring 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 includes indication information of 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.

[0192] In one implementation, before the current AP MLD sends the BTM request frame to the non-AP MLD, the non-AP MLD may also send a BTM inquiry frame to the current AP MLD. After receiving the BTM inquiry frame, the current AP MLD sends a BTM request frame to the current AP MLD.

[0193] Step 804: the non-AP MLD sends a BTM response frame to the current AP MLD. The BTM response frame includes the target AP MLD selected by the non-AP MLD.

[0194] Step 805: The non-AP MLD performs a tentative reassociation with the target AP MLD. The tentative reassociation may be a tentative reassociation over the DS.

[0195] In order to achieve the data transmission between the non-AP MLD and the target AP MLD without interruption when performing the tentative association operation with the current AP MLD, the DS (Over-the-DS) based tentative association operation mode is defined, that is, the non-AP MLD can perform the tentative association operation with the target AP MLD through the current AP MLD:

[0196] For example, the non-AP may send a first request to the current AP MLD, where 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 through the DS. The target AP MLD may establish a second transmission link between the target AP MLD and the non-AP MLD based on the first request. The second transmission link may be an air interface link between the non-AP MLD and the target AP MLD. In one implementation, the target APMLD may send a first response to the current AP MLD through the transparent transmission of the DS. The current AP MLD sends the first response to the non-APMLD. In one implementation, the first request and the first response may be a fast BSS transition (FT) probe request and a FT probe response, respectively.

[0197] In one implementation, when the first request is transmitted through the current AP MLD and DS, the first request does not include operating channel information (OCI), thereby saving signaling overhead of the first request.

[0198] 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 through the DS, and the eighth request is used to request the communication parameters of the target AP MLD. The target AP MLD sends an eighth response to the current AP MLD through the DS, and the current AP MLD sends an eighth response to the non-AP MLD, and the eighth response includes the second key negotiated between the non-AP MLD and the target AP MLD. In one implementation, the eighth request and the eighth response may be an FT request and an FT response, respectively.

[0199] The non-AP MLD sends the ninth request to the current AP MLD, and the current AP MLD transparently transmits the ninth request to the target AP MLD via the DS. The ninth request is used to negotiate the link operation parameters between the non-AP MLD and the target AP MLD. The target AP MLD sends the ninth response to the current AP MLD via the DS. The current AP MLD sends the ninth response to the non-AP MLD, and the ninth response includes the link operation parameters between the non-AP MLD and the target AP MLD. In one implementation, the ninth request and the ninth response may be a FT reassociation request and a FT reassociation response, respectively.

[0200] In one design, Fig. 9 As shown, the FT action frame transparently transmitted between the non-AP MLD and the target AP MLD through the DS and the current AP MLD in the preceding text (including but not limited to the FT query request, FT query response, FT request, FT response, FT reassociation request and FT reassociation response in the preceding text) includes at least one of the following fields: category, FT action, MAC address of the non-AP MLD, MAC address of the target AP MLD, and frame body.

[0201] The category field is used to indicate the category to which the FT action frame belongs. The FT action field includes the value corresponding to FT. Different FT action frames have different values ​​set in the corresponding FT action field. For example, as shown in Table 1:

[0202] Table 1

[0203]

[0204] It can be seen that when Fig. 9 When the FT Action frame is used as an FT reassociation request, the value of the FT Action field is set to 7. Fig. 9 When the middle line frame is used as an FT reassociation response, the value of the FT action field is set to 8. For the FT query request, FT query response, FT request and FT response mentioned above, the same Fig. 9 The format of the FT action frame in is the same as that in Table 1, except that the FT action field value in Table 1 is set to the corresponding value.

[0205] The non-AP MLD field includes the MAC layer address of the non-AP MLD. Specifically, it can be the high MAC layer address of the non-AP MLD, or the low MAC layer address, etc., without limitation. The MAC address of the target AP MLD includes the MAC layer address of the target AP MLD, which can be the high MAC layer address of the target AP MLD, or the low MAC layer address, etc.

[0206] The frame body field is used to carry the frame body corresponding to the FT action frame.

[0207] In one implementation, the FT reassociation request frame, as shown in Table 2, carries at least one of the following information in its frame body.

[0208] Table 2: Information carried in the frame body of the FT reassociation request frame

[0209]

[0210] In one implementation, as shown in Table 3, the frame body of the FT reassociation response carries at least one of the following information:

[0211] Table 3: Information carried in the frame body of the FT reassociation response frame

[0212]

[0213] In an embodiment of the present application, in one design, when the FT reassociation request and the FT reassociation response are transparently transmitted through the DS, an implementation method is:

[0214] 1. The frame body of the FT reassociation request and / or the FT reassociation response does not need to carry the OCI, which is mainly used for verification of channel information, thereby reducing the signaling overhead of the FT reassociation request and / or the FT reassociation response.

[0215] 2. After the current AP MLD and the target AP MLD perform a tentative association using the FT reassociation request and the FT reassociation response, the initial state of the second transmission link established between the non-AP MLD and the target AP MLD is the energy-saving mode, and its state is the energy-saving (doze) state.

[0216] 3. The mobility domain element (MDE) in the frame body of the FT reassociation request and / or the FT reassociation response carries 1-bit indication information, which is used to indicate whether OS (over-the-DS)-based tentative association is supported.

[0217] Step 806: non-AP MLD triggers path switching. Non-AP MLD sends a STA and AP mapping request frame to the target AP MLD. The STA and AP request frame can be used to request the target AP MLD to perform path switching. For the STA and AP mapping request frame, please refer to the third request in the above text.

[0218] With the aforementioned Figure 7a The process is not in Figure 8 In the process, in step 806: the non-AP MLD sends a STA and AP mapping request frame to the target AP MLD, including: the non-AP MLD sends a STA and AP mapping request frame to the current AP MLD. The current AP MLD sends a STA and AP mapping request frame to the target AP MLD through transparent transmission of the DS.

[0219] Step 807: The target AP MLD sends a context transfer request to the current AP MLD.

[0220] Step 808: The current AP MLD sends a context transfer response to the target AP MLD. For the content carried in the context transfer response, please refer to the above description.

[0221] Step 809: The target AP MLD sends a DS-STA-Notify Request to the DS.

[0222] When the DS receives the above DS-STA-notify request, it can update the 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 disconnects the data path with the current AP MLD and establishes a data path with the target AP MLD. For the DS-STA-notify request, please refer to the description of the fourth request in the previous text.

[0223] Step 8010: The current AP MLD deletes the context of the non-AP MLD.

[0224] In one implementation, in step 806, when the non-AP MLD determines to trigger the path switching, it can also send a disassociation frame to the current AP MLD. For the disassociation frame, please refer to the fifth request in the above text. The current AP MLD can 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 stored in it.

[0225] It should be noted that in Figure 8 In the process, before roaming or switching, there is a first transmission link between the non-AP MLD and the current AP MLD. During the roaming or switching process, a second transmission link can be established between the non-AP MLD and the target AP MLD through transparent transmission of DS and / or current APMLD, and the second transmission link includes: non-AP MLD—target AP MLD. After the roaming or switching is completed, the non-AP MLD and the target AP MLD use the second transmission link to perform uplink and / or downlink data transmission. In one design, after step 8011, that is, after the target AP MLD sends a mapping response frame of STA and AP to the non-AP MLD, the target AP MLD and the non-AP MLD use the second transmission link to perform uplink and / or downlink data transmission, and the target APMLD and the non-AP MLD use the second key negotiated by both parties to encrypt and decrypt uplink data and / or downlink data, and the corresponding data is transmitted in the second transmission link.

[0226] It should be noted that, in the previous introduction of this application, the solution of the second embodiment is introduced for single-radio non-AP MLD and / or EMLSR type non-AP MLD. In a possible implementation, the solution of the second embodiment is not limited to only apply to the above two types of non-AP MLD. For example, for a non-AP MLD that can simultaneously transmit and receive data with multiple AP MLDs, the solution provided in the second embodiment can also be adopted without limitation.

[0227] In the solution of the second embodiment, the non-AP MLD is not restricted to have the ability to send and receive data with multiple AP MLDs at the same time. It is also applicable to the non-AP MLD that can only transmit data with one AP MLD at a certain moment, thereby further improving the roaming performance of the non-AP MLD, especially improving the roaming performance of the non-AP MLD and EMLSR non-APMLD of a single radio link.

[0228] [Example 3]

[0229] In the above-mentioned embodiment 1 or embodiment 2, the beacon measurement request sent by the current AP MLD to the non-AP MLD may include indication information of the link corresponding to the serving AP. In one implementation, when the non-AP MLD receives the beacon measurement request, it may perform beacon measurement on each link of the non-AP. In one design, the non-AP MLD may report the link quality of all measured links to the current AP MLD. Alternatively, when 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 link corresponding to the serving AP indicated in the beacon measurement request. Only when the link quality of the current link is greater than or equal to the link quality of the link corresponding to the serving AP, the non-AP MLD reports the link quality of the link to the current AP MLD, otherwise, the link quality of the corresponding link is no longer reported. The design mainly takes the following considerations into account: the non-AP MLD reports the link quality of the measured link to the current AP MLD, and the current AP MLD selects a target AP MLD that meets the conditions based on the link quality of the link reported by it. If the link quality of a link is lower than the link quality of the link corresponding to the serving AP, the link quality of the link is considered to be poor and is not suitable as the target AP MLD for switching. At this time, the non-AP MLD does not need to report the beacon measurement results of the above-mentioned poor quality links, thereby reducing the overhead of reporting beacon measurement results.

[0230] In one implementation, the current AP MLD may send a radio measurement request frame to the non-AP MLD via a link. Upon receiving the radio measurement request frame, the non-AP MLD may perform corresponding measurements on the link of the non-AP MLD and send a radio measurement report frame to the current AP MLD, wherein the radio measurement report frame includes measurement results of the non-AP MLD.

[0231] In one design, Fig.10 As shown, the radio measurement request frame includes at least one of the following fields: category, radio measurement action, dialog token, number of repetitions, or measurement request elements.

[0232] The category field may be used to indicate which category the corresponding wireless measurement request frame belongs to. For example, the wireless measurement request frame may be a frame related to wireless measurement or a frame related to roaming.

[0233] Wireless measurement action: can be used to indicate the type of the wireless measurement request. For example, the wireless measurement action can indicate that the corresponding frame is a request frame or a measurement frame. Of course, in the embodiment of the present application, Fig.10 The wireless measurement request frame shown is used to request the non-AP MLD to perform wireless measurement. At this time, the type of the frame indicated by the wireless measurement action is a request frame.

[0234] Dialog token: used to identify the correspondence between the request frame and the response frame. In one implementation, the response frame can also use Fig.10 The format shown in Figure 2. A pair of request frames and response frames carry the same value of the conversation token.

[0235] Repetition count: Indicates the number of repetitions of the wireless measurement. For example, if the repetition count is set to 0, it means that non-APMLD does not need to repeat the measurement and only needs to be measured once. Or, if the repetition count is set to 65535, it means that non-AP MLD needs to repeat the measurement until the measurement is canceled. The repetition count field is an implementation method, that is, Fig.10 The frame format shown may not include a repetition count field.

[0236] Measurement request element: used to request beacon measurement, or to indicate the received signal strength indication (RSSI) of the channel. In one design, when the measurement request element instructs the non-AP MLD to perform RSSI measurement, the non-AP MLD may report the RSSI of the measured link to the current AP MLD. That is, in the above-mentioned embodiments 1 and 2, the current AP MLD may request the non-AP MLD to report the RSSI of the measured link, etc., in addition to requesting the non-AP MLD to perform beacon measurement. Alternatively, when the measurement request element instructs the non-AP MLD to perform beacon measurement, the non-AP MLD may jump to the channel of the link to be measured to send a probe request. The current APMLD replies with a probe response on the information of the corresponding link. The non-AP MLD determines the link quality of the corresponding link based on the received probe response. Alternatively, the non-AP MLD may directly listen to the beacon frame on the link to be measured. The non-AP MLD determines the link quality of the corresponding link based on the listened beacon frame.

[0237] Further, in Fig.10 In the frame format of , when the measurement request element instructs the non-AP MLD to perform beacon measurements, Fig.10 The frame grid in the frame may also include: a beacon reporting subelement. In one implementation, the beacon reporting subfield includes: a reporting condition field and / or a threshold / offset reference field, etc. In one design, when the value of the reporting condition field is set to a first value, the first value includes but is not limited to 7, indicating that when the difference between the received signal signal-to-noise ratio of the corresponding link measured by the non-AP MLD and the received signal signal-to-noise ratio of the current serving AP is greater than or equal to the value in the aforementioned threshold / offset reference field, the beacon measurement result is reported to the current AP MLD, otherwise, the beacon measurement result is no longer reported to the current AP.

[0238] In one design, in a multi-link scenario, the current AP MLD can send a beacon measurement request to the non-AP MLD through any of its affiliated APs that have a link with the non-AP MLD. At this time, there may be ambiguity about the serving AP for the non-AP MLD. At this time, the non-AP MLD cannot clearly determine which AP is used as the serving AP for the aforementioned comparison of received signal-to-noise ratios. In order to solve the above problem, the following solution is proposed:

[0239] Solution 1: Fig.10In the frame format shown, in addition to the reporting condition field and / or the threshold / offset reference field, a link ID field is also included. Fig.11 As shown. The link identification field may indicate the link corresponding to the serving AP. Further, in addition to the link identification field, a reserved field is also included. This field may be referred to as a link identification information field (link ID info field). The link identification field may occupy 4 bits, and the reserved field may occupy 4 bits. Alternatively, in Fig.10 In the frame format shown in FIG. 1 , a multi-link operation (MLO) link information subelement is carried. Fig.11 As shown, the sub-segment includes: a field identifier (elementID), a length (length), an extended field identifier (element ID extension) and a link identifier in a bitmap form (link ID bitmap).

[0240] Solution 2: Limit the links on which the current AP MLD sends beacon measurement requests, and stipulate that the AP corresponding to the link that sends the beacon measurement request is the service AP. That is, for the non-AP MLD side, on whichever link it receives the beacon measurement request, the AP corresponding to the link is the service AP.

[0241] Through the above method, the non-AP MLD can report the beacon measurement results that meet the conditions, which can reduce the reporting overhead compared to reporting the beacon measurement results of all links.

[0242] It should be noted that in the embodiments of the present application:

[0243] 1. Focus on describing the differences between different processes. The descriptions of different processes can refer to each other.

[0244] 2. In Figure 3 , Figure 5 , Figure 7a and Figure 8 In the process, there is no restriction on the order in which different steps are executed.

[0245] 3. In Figure 3 , Figure 5 , Figure 7a and Figure 8 The process may include more steps or fewer steps than the flowchart or text description, without limitation.

[0246] In the above embodiments provided by the present application, the methods provided by the embodiments of the present application are introduced from the perspective of the interaction of each device. In order to implement the methods provided by the embodiments of the present application, the non-AP MLD, the current AP MLD and the target APMLD may include hardware structures and / or software modules, and implement the above functions in the form of hardware structures, software modules, or hardware structures plus software modules. Whether one of the above functions is executed in the form of hardware structures, software modules, or hardware structures plus software modules depends on the design constraints of the specific application of the technical solution.

[0247] Fig.12 and Fig.13 A schematic diagram of the structure of possible devices provided in the embodiments of the present application. These communication devices can implement one or more corresponding functions in the above method embodiments. For example, the functions implemented by the target AP MLD, the current AP MLD or the non-AP MLD, etc., may thus achieve the beneficial effects possessed by the above method embodiments.

[0248] like Fig.12 As shown, the communication device 1200 includes a processing unit 1210 and a transceiver unit 1220 .

[0249] Exemplarily, the processing unit 1210 may also be referred to as a processor, a processing board, a processing module, a processing device, etc. The transceiver unit 1220 may also be referred to as a transceiver, a transceiver, a transceiver module, a transceiver device, a communication unit, etc. Further, 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 may be two independent units, etc.

[0250] In one design, communication device 1200 is used to implement Figure 3 The functions of the target AP MLD in the target AP MLD are as follows: the transceiver unit 1220 is used to receive the first downlink data sent by the current AP MLD, the first downlink data is data encrypted with a first key, the first key is the key negotiated between the current AP MLD and the non-access point non-AP MLD, and the target AP MLD is the AP MLD after the non-AP MLD is transferred to the basic service set BSS; the processing unit 1210 is used to perform low media access control LMAC layer and physical layer processing on the first downlink data to obtain second downlink data; the transceiver unit 1220 is also used to send the second downlink data to the non-AP MLD.

[0251] In one design, communication device 1200 is used to implement Figure 3 The current AP MLD function is as follows:

[0252] The transceiver unit 1220 is used to receive the third downlink data sent by the distributed system DS; the processing unit 1210 is used to encrypt the third downlink data using the first key to obtain the first downlink data, where the first key is the key negotiated between the current AP MLD and the non-access point non-AP MLD; the transceiver unit 1220 is also used to send the first downlink data to the target AP MLD, where the target AP MLD is the AP MLD after the non-AP MLD is transferred to the basic service set BSS.

[0253] In one design, communication device 1200 is used to implement Figure 3 The functions of the non-AP MLD are as follows: a transceiver unit 1220 is used to receive data sent by a current access point AP MLD through a target access point AP MLD, wherein the target AP MLD is the AP MLD of the non-AP MLD after the basic service set BSS is transferred; the data is data encrypted by the current AP MLD using a first key, wherein the first key is a key negotiated between the current AP MLD and the non-access point non-AP MLD; a processing unit 1210 is used to decrypt the data using the first key.

[0254] In one design, communication device 1200 is used to implement Figure 5 The function of the target AP MLD is as follows:

[0255] The transceiver unit 1220 is used to receive first uplink data sent by a non-access point non-AP MLD, where the first uplink data is data encrypted with a first key, where the first key is a key negotiated between the current AP MLD and the non-AP MLD, and the target AP MLD is the AP MLD after the non-AP MLD is transferred to the basic service set BSS; the processing unit 1210 is used to perform physical layer and low media access control LMAC layer processing on the first uplink data to determine second uplink data; the transceiver unit 1220 is used to send the second uplink data to the current AP MLD.

[0256] In one design, communication device 1200 is used to implement Figure 5 The current AP MLD function is as follows:

[0257] The transceiver unit 1220 is used to receive the second uplink data sent by the target AP MLD, where the target AP MLD is the AP MLD of the non-AP MLD after the basic service set BSS is transferred; the processing unit 1210 is used to perform high media access control UMAC layer processing on the second uplink data, and decrypt the second uplink data using the first key to determine the third uplink data, where the first key is the key negotiated between the current AP MLD and the non-AP MLD; the transceiver unit 1220 is also used to send the third uplink data to the distributed system DS.

[0258] In one design, communication device 1200 is used to implement Figure 5 The functions of non-AP MLD are as follows:

[0259] The processing unit 1210 is used to encrypt the uplink data to be transmitted using a first key to determine the first uplink data, where the first key is a key negotiated between the current access point AP MLD and the non-AP MLD; the transceiver unit 1220 is used to send the first uplink data to the current AP MLD through a target AP MLD, where the target AP MLD is the AP MLD of the non-APMLD after the basic service set BSS is transferred.

[0260] For more detailed description of the processing unit 1210 and the transceiver unit 1220, please refer to the above method embodiment. Figure 3 or Figure 5 The description is not repeated here.

[0261] The division of units in the embodiments of the present application is schematic and is only a logical function division. There may be other division methods in actual implementation. In addition, each functional unit in the embodiments of the present application may be integrated into a physical device (for example, a processor), or each functional unit may be a separate physical device, or two or more units may be integrated into a unit for implementation, and the above-mentioned integrated unit may be implemented in the form of hardware, or in the form of software functional modules, etc.

[0262] Fig.13 Another structural diagram of the communication device 1300 provided in an embodiment of the present application is shown. For example, Fig.13 The communication device 1300 shown may be Fig.12 A hardware circuit implementation of the communication device 1200 shown in FIG. Fig.13 Only the essential parts of the communication device are shown.

[0263] like Fig.13As shown, 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.

[0264] For example, the processor 1310 may be a central processing unit (CPU), other general-purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, transistor logic devices, hardware components or any combination thereof. The general-purpose processor may be a microprocessor or any conventional processor. The interface circuit 1320 may be a transceiver or an input-output circuit, etc.

[0265] Optionally, the communication device 1300 may further include a memory 1330 for storing instructions executed by the processor 1310 or storing input data required by the processor 1310 to execute instructions or storing data generated after the processor 1310 executes instructions. For example, instructions may also be referred to as computer programs, or computer program codes, etc.

[0266] For example, the memory 1330 may be a random access memory (RAM), a flash memory, a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), a register, a hard disk, a mobile hard disk, a CD-ROM, or any other form of storage medium known in the art.

[0267] When the communication device 1300 is used to implement Figure 3 or Figure 5 When the method of selecting the target AP MLD, the current AP MLD or the non-AP MLD is used, the processor 1310 is used to implement the function of the processing unit 1210, and the interface circuit 1320 is used to implement the function of the transceiver unit 1220.

[0268] In one design, the interface circuit 1320 is used to receive signals from other communication devices other than the communication device 1300 and transmit them to the processor 1310, or send signals from the processor 1310 to other communication devices other than the communication device. The processor 1310 implements the above through logic circuits or executes code instructions. Figure 3 or Figure 5 The target AP MLD, current AP MLD, or non-AP MLD function.

[0269] The embodiment of the present application also provides a communication device, which includes a processor and a memory, the processor and the memory are coupled, and the processor is used to implement Figure 3 or Figure 5 For example, the processor may execute instructions in the memory so that the communication device implements one or more functions in the above method embodiments, such as by Figure 3 or Figure 5 The target AP MLD, current AP MLD, or non-AP MLD

[0270] In one exemplary embodiment, the storage medium is coupled to the processor so that the processor can read information from the storage medium and write information to the storage medium. Of course, the storage medium can also be a component of the processor. The processor and the storage medium can be located in an ASIC. In addition, the ASIC can be located in Figure 3 or Figure 5 The processor and storage medium may also exist as discrete components. Figure 3 or Figure 5 The target AP MLD, current AP MLD, or non-AP MLD in the

[0271] The present application also provides a computer-readable storage medium, which stores instructions, which may also be referred to as computer programs, computer program codes, etc. The instructions are executed on a computer, so that the computer executes the method in the above embodiment. Figure 3 or Figure 5 The target AP MLD, current AP MLD, or non-AP MLD function.

[0272] Optionally, the computer may be a general-purpose computer, a special-purpose computer, a computer network, a network device, a user device or other programmable device. The computer program or instruction may be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer program or instruction may be transmitted from one website, computer, server or data center to another website, computer, server or data center by wired or wireless means. The computer-readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server or data center that integrates one or more available media. The available medium may be a magnetic medium, such as a floppy disk, a hard disk, or a magnetic tape; it may also be an optical medium, such as a digital video disc; it may also be a semiconductor medium, such as a solid-state hard disk. The computer-readable storage medium may be a volatile or non-volatile storage medium, or may include both volatile and non-volatile types of storage media.

[0273] The present application also provides a computer program product, including a computer program or an instruction. When the computer program or the instruction is executed on a computer, the above Figure 3 or Figure 5 The method of the target AP MLD, current AP MLD or non-AP MLD in the target AP MLD is executed. 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 the computer, all or part of the embodiments of the present application are executed. Figure 3 or Figure 5 The process or function of the target APMLD, current AP MLD or non-AP MLD.

[0274] The method in the embodiment of the present application can be implemented in whole or in part by software, hardware, firmware or any other combination. When implemented by software, it can be implemented in whole or in part in the form of a computer program product.

[0275] The present application also provides a chip, which includes a processor, the processor is coupled to a memory, and the processor is used to execute a computer program or instruction stored in the memory, so that the chip implements Figure 3 or Figure 5 The target AP MLD, current AP MLD, or non-AP MLD function.

[0276] An embodiment of the present application also provides a communication system, including: a first communication device, a second communication device and a third communication device.

[0277] Among them, the first communication device can implement the above Figure 3 or Figure 5The second communication device can implement the above Figure 3 or Figure 5 The third communication device can implement the above Figure 3 or Figure 5 The specific structure of the first communication device, the second communication device or the third communication device can refer to the above description, for example Fig.12 or Fig.13 The structure description in .

[0278] In the description of this application, "at least one" means one or more, and "more than one" means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. In the text description of this application, the character " / " generally indicates that the associated objects before and after are in an "or" relationship; "including at least one of A, B or C" can mean: including A; including B; including C; including A and B; including A and C; including B and C; including A, B and C.

[0279] The various numbers involved in the embodiments of the present application are only for the convenience of description and are not used to limit the scope of the embodiments of the present application. The size of the sequence number of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic.

Claims

1. A communication method, characterized in that: include: The target access point AP multi-link device MLD receives first downlink data sent by the current AP MLD, where the first downlink data is data encrypted by a first key, where the first key is a key negotiated between the current AP MLD and a non-access point non-AP MLD, and the target AP MLD is the AP MLD of the non-AP MLD after the basic service set BSS is transferred; The target AP MLD performs low media access control LMAC layer and physical layer processing on the first downlink data to obtain second downlink data; The target AP MLD sends the second downlink data to the non-AP MLD.

2. A communication method, characterized in that: include: The target access point AP multi-link device MLD receives first uplink data sent by the non-access point non-AP MLD, where the first uplink data is data encrypted with a first key, where the first key is a key negotiated between 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 is transferred; The target AP MLD performs physical layer and low media access control LMAC layer processing on the first uplink data to determine second uplink data; The target AP MLD sends the second uplink data to the current AP MLD.

3. The method according to claim 1 or 2, characterized in that There is a first transmission link between the non-AP MLD and the current AP MLD, and the method further includes: The target AP MLD receives a first request, where the first request is used to request to establish a second transmission link between the non-AP MLD and the target AP MLD; The target AP MLD establishes a second transmission link with the non-AP MLD.

4. The method according to claim 3, characterized in that The first request includes indication information for starting dual-link transmission of the non-AP MLD, and the dual-link includes the first transmission link and the second transmission link.

5. The method according to any one of claims 1 to 4, characterized in that Also includes: The target AP MLD sends a second request to the current AP MLD, where the second request is used to request to enable dual-link transmission of 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 MAC layer service data units MSDU allowed to be aggregated by the target AP MLD.

6. The method according to any one of claims 1 to 5, characterized in that Also includes: The target AP MLD receives a third request, where the third request is used to request triggering a path switch of the non-AP MLD; The target AP MLD sends a fourth request to the distributed system DS, wherein 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: a mapping relationship between the non-AP MLD and the target AP MLD.

7. The method according to any one of claims 3 to 6, characterized in that The first request and / or the third request is sent by the non-AP MLD, and the first request and / or the third request is transmitted through the air interface between the non-AP MLD and the target AP MLD, or is transmitted through the current AP MLD and DS.

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

9. The method according to any one of claims 6 to 8, characterized in that 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 sends a context transfer request to the current AP MLD; The target AP MLD receives a context transfer response sent by the current AP MLD, where the context transfer response includes the context information of the non-AP MLD.

10. The method according to claim 9, characterized in that The context transfer response also includes at least one of the following: a block determination protocol of a service identifier TID, a window start position of a send buffer area of ​​the TID, a window size of a send buffer area of ​​the TID, a window start position of an uplink receiving end scoreboard, a window size of the uplink receiving end scoreboard, a window start position of a receive reordering buffer area, a window size of the receive reordering buffer area, a maximum packet sequence number PN value currently received, or an uplink replay counter.

11. The method according to any one of claims 1 to 10, characterized in that 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 use a second key negotiated between the two to encrypt and decrypt uplink data and / or downlink data.

12. A communication method, characterized in that: include: The current access point AP multi-link device MLD receives the third downlink data sent by the distributed system DS; The current AP MLD encrypts the third downlink data using a first key to obtain first downlink data, where the first key is a key negotiated between the current AP MLD and a non-access point non-AP MLD; The current AP MLD sends the first downlink data to a target AP MLD, where the target AP MLD is the AP MLD of the non-APMLD after the basic service set BSS is transferred.

13. A communication method, characterized in that: include: The current access point AP multi-link device MLD receives the second uplink data sent by the target AP MLD, where the target AP MLD is the AP MLD of the non-access point non-AP MLD after the basic service set BSS is transferred; The current AP MLD performs high media access control (UMAC) layer processing on the second uplink data, and decrypts the second uplink data using a first key to determine third uplink data, where the first key is a key negotiated between the current AP MLD and the non-AP MLD; The current AP MLD sends the third uplink data to the distributed system DS.

14. The method according to claim 12 or 13, characterized in that There is a first transmission link between the current AP MLD and the non-AP MLD, further comprising: The current AP MLD receives a second request sent by the target AP MLD, where the second request is used to request to enable dual-link transmission of the non-AP MLD, and the second request includes: the maximum media access control MAC layer protocol data unit MPDU length supported by the target AP MLD, and / or the maximum number of MAC layer service data units MSDU allowed to be aggregated by the target AP MLD, and the dual link includes the first transmission link and a second transmission link between the non-AP MLD and the target AP MLD.

15. The method according to any one of claims 12 to 14, characterized in that Also includes: The current AP MLD receives a fifth request sent by the non-AP MLD, where the fifth request is used to request to disconnect a first transmission link between the non-AP MLD and the current AP MLD, and the fifth request includes first indication information, where the first indication information instructs the current AP MLD to retain block acknowledgment BA information and / or context information of the non-AP MLD and cache data not sent by the non-AP MLD; The current AP MLD sends a sixth request to the DS, where the sixth request is used to request deletion of a mapping relationship between the non-AP MLD and the current AP MLD stored in the DS.

16. The method according to any one of claims 12 to 15, characterized in that Also includes: The current AP MLD receives a context transfer request sent by the target AP MLD; The current AP MLD sends a context transfer response to the target AP MLD, where the context transfer response includes the context information of the non-AP MLD.

17. The method according to claim 16, characterized in that The context transfer response further includes at least one of the following: a block determination protocol of a service identifier TID, a window start position of a send buffer area of ​​the TID, a window size of the send buffer area of ​​the TID, a window start position of an uplink receiving end scoreboard, a window size of the uplink receiving end scoreboard, a window start position of a receive reordering buffer area, a window size of the receive reordering buffer area, a maximum packet sequence number PN value currently received, or an uplink replay counter.

18. The method according to any one of claims 12 to 17, characterized in that Also includes: The current AP MLD sends a beacon measurement request to the non-AP MLD, where the beacon measurement request includes indication information of a corresponding link of the serving AP.

19. The method according to any one of claims 12 to 18, characterized in that Also includes: The current AP MLD sends a seventh request to the non-AP MLD, wherein the seventh request includes second indication information, and the second indication information instructs the non-AP MLD to retain the BA information and / or context information of the non-AP MLD and cache the data not sent by the non-AP MLD.

20. A communication method, characterized in that: include: The non-AP multi-link device MLD receives data sent by the current access point AP MLD through the target access point AP MLD, where the target AP MLD is the AP MLD of the non-AP MLD after the basic service set BSS is transferred; the data is data encrypted by the current AP MLD using the first key, where the first key is a key negotiated between the current AP MLD and the non-AP MLD; The non-AP MLD decrypts the data using the first secret key.

21. A communication method, characterized in that: include: The non-AP multi-link device MLD uses a first key to encrypt the uplink data to be transmitted and determine the first uplink data, where the first key is a key negotiated between the current access point AP MLD and the non-AP MLD; The non-AP MLD sends the first uplink data to the current AP MLD through a target AP MLD, where the target AP MLD is the AP MLD of the non-AP MLD after the basic service set BSS is transferred.

22. The method according to claim 20 or 21, characterized in that There is a first transmission link between the non-AP MLD and the current AP MLD, further comprising: The non-AP MLD sends a first request, where the first request is used to request to establish a second transmission link between the non-AP MLD and the target AP MLD.

23. The method of claim 22, wherein: The first request includes indication information for starting dual-link transmission of the non-AP MLD, and the dual-link includes the first transmission link and the second transmission link.

24. The method according to any one of claims 20 to 23, characterized in that Also includes: The non-AP MLD sends a third request, where the third request is used to request triggering of path switching of the non-AP MLD.

25. The method according to any one of claims 22 to 24, characterized in that The first request and / or the third request is sent to the target AP MLD, and the first request and / or the third request is transmitted through the air interface between the non-APMLD and the target AP MLD, or is transmitted through the current AP MLD and DS.

26. The method of claim 25, wherein: When the first request is transmitted through the current AP MLD and DS, the first request does not include operating channel information OCI.

27. The method according to any one of claims 20 to 26, characterized in that Also includes: The non-AP MLD sends a fifth request to the current AP MLD, wherein the fifth request includes first indication information, and the first indication information instructs the current AP MLD to retain the block acknowledgment BA information and / or context information of the non-AP MLD and cache the data not sent by the non-AP MLD.

28. The method according to any one of claims 20 to 27, characterized in that Also includes: The non-AP MLD receives the beacon measurement request sent by the current AP MLD, where the beacon measurement request includes indication information of a link corresponding to the serving AP.

29. The method according to any one of claims 20 to 28, characterized in that Also includes: The non-AP MLD receives a seventh request sent by the current AP MLD, where the seventh request includes second indication information, and the second indication information instructs the non-AP MLD to retain the BA information and / or context information of the non-AP MLD and cache data not sent by the non-AP MLD.

30. The method according to any one of claims 20 to 29, characterized in that 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 use a second key negotiated between the two to encrypt and decrypt uplink data and / or downlink data.

31. A communication device, characterized in that: The method comprises a unit for implementing the method described in any one of claims 1 to 11, or a unit for implementing the method described in any one of claims 12 to 19, or a unit for implementing the method described in any one of claims 20 to 30.

32. A communication device, characterized in that: include: A memory for storing program instructions; A processor, configured to execute the 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.

33. A device, characterized in that: The device comprises a processor and an interface circuit, wherein the interface circuit is used to receive a signal from another device outside the device and transmit it to the processor or send a signal from the processor to another device outside the device, and the processor enables the device to implement the method as described in any one of claims 1 to 11, or the method as described in any one of claims 12 to 19, or the method as described in any one of claims 20 to 30 through a logic circuit or executing code instructions.

34. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores instructions, which are executed on a computer to cause the computer to execute the method of any one of claims 1 to 11, or the method of any one of claims 12 to 19, or the method of any one of claims 20 to 30.

35. A computer program product, characterized in that The method comprises a computer program or an instruction, which, when executed by a device, causes the method according to any one of claims 1 to 11 to be executed, or the method according to any one of claims 12 to 19 to be executed, or the method according to any one of claims 20 to 30 to be executed.

36. A chip, characterized in that: The invention comprises a processor coupled to a memory and configured to execute a computer program or instruction stored in the memory, so that a communication device comprising the chip executes the method described in any one of claims 1 to 11, or executes the method described in any one of claims 12 to 19, or executes the method described in any one of claims 20 to 30.

37. A communication system, characterized in that: include: A first communication device, the first communication device being configured to perform the method according to any one of claims 1 to 11; A second communication device, the second communication device being configured to perform the method according to any one of claims 12 to 19; A third communication device, wherein the second communication device is configured to execute the method according to any one of claims 20 to 30.

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