Communication method and device

Abstract

The embodiment of the invention relates to a communication method and device. The method comprises the steps that an APMLD receives first downlink data sent by a current AP MLD; the target AP MLD encrypts the first downlink data by using the second secret key to obtain second downlink data; the second secret key is a secret key negotiated by a target AP MLD and a non-AP MLD, and the 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 sends the second downlink data to the non-AP MLD.

Description

[0001] This application is a divisional application. The original application has the application number 202310952314.0 and the original application date is July 29, 2023. The entire contents of the original application are incorporated herein by reference. Technical Field

[0002] This application relates to the field of communication technology, and in particular to a communication method and apparatus. Background Technology

[0003] Due to factors such as the movement of non-access point (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

[0004] This application provides a communication method and apparatus that enables data transmission between the current AP MLD and the target AP MLD during roaming, thereby improving the roaming performance of non-AP MLDs.

[0005] In a first aspect, a communication method is provided, comprising: a target access point (AP) multi-link device (MLD) receiving first downlink data sent by a current AP MLD; the target AP MLD encrypting the first downlink data using a second key to obtain second downlink data; the second key being a key negotiated between the target AP MLD and a non-access point (non-AP MLD), the target AP MLD being the AP MLD after the non-AP MLD has been transferred to a Basic Service Set (BSS); and the target AP MLD sending the second downlink data to the non-AP MLD.

[0006] Secondly, a communication method is provided, comprising: a target access point (AP) multi-link device (MLD) receiving first uplink data sent by a non-access point (non-AP MLD); the target AP MLD decrypting the first uplink data using a second key to obtain second uplink data, wherein the second key is a key negotiated between the target AP MLD and the non-AP MLD, and the target AP MLD is the AP MLD after the non-AP MLD has been transferred to a Basic Service Set (BSS); and the target AP MLD sending the second uplink data to the current AP MLD.

[0007] In one design, a first transmission link exists between the non-AP MLD and the current AP MLD. The method further includes: the target AP MLD receiving a first request, the first request being used to request the establishment of a second transmission link between the non-AP MLD and the target AP MLD; and the target AP MLD establishing the second transmission link with the non-AP MLD.

[0008] In one design, the first request includes an indication to enable dual-link transmission of the non-AP MLD, the dual links including the first transmission link and the second transmission link.

[0009] In one design, the target AP MLD sends a second request to the current AP MLD, the second request being used to request the activation of dual-link transmission of the non-AP MLD.

[0010] In one design, the method further includes: the target AP MLD receiving a third request, the third request being used to request triggering a path switch for the non-AP MLD; the target AP MLD sending a fourth request to the distributed system DS, the fourth request being used to request the DS to update the stored mapping relationship between the non-AP MLD and the current AP MLD to: the mapping relationship between the non-AP MLD and the target AP MLD.

[0011] In one design, the first request and / or the third request are sent by the non-AP MLD, and the first request and / or the third request are transmitted over the air interface between the non-AP MLD and the target AP MLD, or transmitted through the current AP MLD and DS.

[0012] In one design, when the first request is transmitted through the current AP MLD and DS, the first request does not include Operation Channel Information (OCI).

[0013] 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, the method further includes: the target AP MLD sending a context transfer request to the current AP MLD; the target AP MLD receiving a context transfer response sent by the current AP MLD, the context transfer response including context information of the non-AP MLD.

[0014] In one design, the context transfer response further includes at least one of the following: a block acknowledgment protocol for the service identifier TID, the window start position of the TID's transmit buffer, the window size of the TID's transmit buffer, the window start position of the uplink receiver scoreboard, the window size of the uplink receiver scoreboard, the window start position of the receive reordering buffer, the window size of the receive reordering buffer, the currently received maximum packet sequence number PN value, or an uplink replay counter.

[0015] 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 and / or downlink data.

[0016] Thirdly, a communication method is provided, comprising: a current access point (AP) multi-link device (MLD) receiving third downlink data sent by a distributed system (DS); the current AP MLD performing high media access control (MAC) layer processing on the third downlink data to obtain first downlink data, wherein the high MAC layer processing does not include encrypting the third downlink data; and the current AP MLD sending the first downlink data to a target AP MLD, wherein the target AP MLD is a non-access point (non-AP MLD) after a basic service set (BSS) transfer.

[0017] Fourthly, a communication method is provided, comprising: a current access point (AP) multi-link device (MLD) receiving second uplink data sent by a target AP MLD, the second uplink data being data decrypted using a second key, the second key being a key negotiated between the target AP MLD and a non-access point (non-AP MLD), the target AP MLD being the AP MLD after the non-AP MLD has been transferred to a Basic Service Set (BSS); the current AP MLD performing high media access control (MAC) layer processing on the second uplink data to obtain third uplink data, the high MAC layer processing not including decryption of the second uplink data; and the current AP MLD sending the uplink data to a distributed system (DS).

[0018] In one design, the processing of the high MAC layer includes: duplicate detection of the uplink data packets.

[0019] In one design, a first transmission link exists between the current AP MLD and the non-AP MLD, and the design further includes: The current AP MLD receives a second request sent by the target AP MLD. The second request is used to request the activation of dual-link transmission of the non-AP MLD. The dual-link includes the first transmission link and a second transmission link between the non-AP MLD and the target AP MLD.

[0020] In one design, the method further includes: the current AP MLD receiving a fifth request sent by the non-AP MLD, the fifth request being used to request disconnection of the 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 the block acknowledgment (BA) information and / or context information of the non-AP MLD, and to cache data not sent by the non-AP MLD; the current AP MLD sending a sixth request to the DS, the sixth request being used to request deletion of the mapping relationship between the non-AP MLD and the current AP MLD stored in the DS.

[0021] In one design, the method further includes: the current AP MLD receiving a context transfer request sent by the target AP MLD; the current AP MLD sending a context transfer response to the target AP MLD, the context transfer response including context information of the non-AP MLD.

[0022] In one design, the context transfer response further includes at least one of the following: a block acknowledgment protocol for the service identifier TID, the window start position of the TID's transmit buffer, the window size of the TID's transmit buffer, the window start position of the uplink receiver scoreboard, the window size of the uplink receiver scoreboard, the window start position of the receive reordering buffer, the window size of the receive reordering buffer, the currently received maximum packet sequence number PN value, or an uplink replay counter.

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

[0024] In one design, the method further includes: the current AP MLD sending a seventh request to the non-AP MLD, the seventh request including second indication information, the second indication information instructing the non-AP MLD to retain the BA information and / or context information of the non-AP MLD, and to cache data not sent by the non-AP MLD.

[0025] Fifthly, a communication method is provided, comprising: a non-access point (non-AP) multi-link device (MLD) receiving second downlink data sent by a target access point (AP MLD), wherein the target AP MLD is the AP MLD after the non-AP MLD has been transferred to a Basic Service Set (BSS); the non-AP MLD decrypting the second downlink data using a second key to obtain fourth downlink data, wherein the second key is a key negotiated between the target AP MLD and the non-AP MLD; the non-AP MLD receiving fifth downlink data sent by a current AP MLD; and the non-AP MLD decrypting the fifth downlink data using a first key to obtain sixth downlink data, wherein the first key is a key negotiated between the current AP MLD and the non-AP MLD.

[0026] A sixth aspect provides a communication method, comprising: a non-access point (non-AP) multi-link device (MLD) encrypting uplink data to be transmitted using a second key to obtain first uplink data, wherein the second key is a key negotiated between a target access point (AP MLD) and the non-AP MLD; the non-AP MLD sending the first uplink data to the target AP MLD; the non-AP MLD encrypting the uplink data to be transmitted using the first key to obtain fourth uplink data, wherein the first key is a key negotiated between the current AP MLD and the non-AP MLD; the non-AP MLD sending the fourth uplink data to the current AP MLD, wherein the target AP MLD is the AP MLD of the non-AP MLD after a Basic Service Set (BSS) transfer.

[0027] In one design, a first transmission link exists between the non-AP MLD and the current AP MLD, and the design further includes: The non-AP MLD sends a first request, which is used to request the establishment of a second transmission link between the non-AP MLD and the target AP MLD.

[0028] In one design, the first request includes an indication to enable dual-link transmission of the non-AP MLD, the dual links including the first transmission link and the second transmission link.

[0029] In one design, the non-AP MLD also includes sending a third request, the third request being used to request triggering a path switch for the non-AP MLD.

[0030] In one design, the first request and / or the third request are sent to the target AP MLD, and the first request and / or the third request are transmitted over the air interface between the non-AP MLD and the target AP MLD, or through the current AP MLD and the distributed system DS.

[0031] In one design, when the first request is transmitted via the current AP MLD and DS, the first request does not include Operation Channel Information (OCI).

[0032] In one design, the non-AP MLD further includes sending a fifth request to the current AP MLD, the fifth request including first indication information, the first indication information instructing the current AP MLD to retain the block acknowledgment (BA) information and / or context information of the non-AP MLD, and to cache data not sent by the non-AP MLD.

[0033] In one design, the non-AP MLD also includes receiving a beacon measurement request sent by the current AP MLD, wherein the beacon measurement request includes indication information of the link corresponding to the serving AP.

[0034] In one design, the non-AP MLD further includes: the non-AP MLD receiving a seventh request sent by the current AP MLD, the seventh request including second indication information, the second indication information instructing the non-AP MLD to retain the BA information and / or context information of the non-AP MLD, and to cache data not sent by the non-AP MLD.

[0035] 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 and / or downlink data.

[0036] In one design, in all of the above aspects, data transmission or reception between the current AP MLD and the target AP MLD is carried out using a transparent transmission method.

[0037] In a seventh aspect, an apparatus is provided capable of implementing the method of the first or second aspect described above. For example, the apparatus includes means for performing the first aspect. The apparatus can be implemented in hardware, in software, or by hardware executing corresponding software implementations.

[0038] In one design, the device includes a unit that performs the first or second aspect described above.

[0039] In one design, the device includes a processor and a memory, the processor being configured to execute a computer program or instructions stored in the memory, such that the device implements the method described in the first or second aspect above.

[0040] In one design, the device includes a processor and an interface circuit, the interface circuit being used to receive signals from other devices outside the device and transmit them to the processor, or to send signals from the processor to other devices outside the device, the processor being used to implement the method in the first or second aspect described above via logic circuits or executing code instructions.

[0041] Eighthly, an apparatus is provided that can implement the methods of the third or fourth aspect described above. For example, the apparatus includes means for performing the methods corresponding to the third or fourth aspect. The apparatus can be implemented in hardware, in software, or by hardware executing corresponding software implementations.

[0042] In one design, the device includes a unit that performs the third or fourth aspect described above.

[0043] In one design, the device includes a processor and a memory, the processor being used to execute computer programs or instructions stored in the memory, such that the device implements the methods described in the third or fourth aspect above.

[0044] In one design, the device includes a processor and an interface circuit, the interface circuit being used to receive signals from other devices outside the device and transmit them to the processor, or to send signals from the processor to other devices outside the device, the processor being used to implement the methods in the third or fourth aspect above via logic circuits or executing code instructions.

[0045] Ninthly, an apparatus is provided that can implement the methods of the fifth or sixth aspect described above. For example, the apparatus includes means for performing the methods corresponding to the fifth or sixth aspect. The apparatus can be implemented in hardware, in software, or by hardware executing corresponding software implementations.

[0046] In one design, the device includes a unit that performs the fifth or sixth aspect described above.

[0047] In one design, the device includes a processor and a memory, the processor being used to execute computer programs or instructions stored in the memory, such that the device implements the methods described in the fifth or sixth aspect above.

[0048] In one design, the device includes a processor and an interface circuit, the interface circuit being used to receive signals from other devices outside the device and transmit them to the processor, or to send signals from the processor to other devices outside the device, the processor being used to implement the methods in the fifth or sixth aspect above via logic circuits or executing code instructions.

[0049] In a tenth aspect, a computer-readable storage medium is provided, storing a computer program or instructions that, when executed on a computer, cause the computer to implement the methods described in the first to second aspects.

[0050] Eleventhly, a computer program product is provided, comprising a computer program or instructions that, when executed by a computer, cause the methods of the first or second aspect described above to be performed.

[0051] In a twelfth aspect, a chip is provided, including a processor coupled to a memory for executing a computer program or instructions stored in the memory, such that the chip implements the methods of the first or second aspect described above.

[0052] In a 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 or second aspect described above, the second communication device is used to implement the method of the third or fourth aspect described above, and the third communication device is used to implement the method of the fifth or sixth aspect described above. Attached Figure Description

[0053] Figure 1 A schematic diagram of a multi-link device (MLD) provided in an embodiment of this application; Figure 2 A schematic diagram illustrating the application scenarios provided in the embodiments of this application; Figure 3 A flowchart of downlink data transmission provided for embodiments of this application; Figure 4 This is a schematic diagram illustrating the processing of downlink data provided in an embodiment of this application; Figure 5 A flowchart of uplink data transmission provided in the embodiments of this application; Figure 6 This is a schematic diagram of uplink data processing provided in an embodiment of this application; Figure 7a A flowchart illustrating roaming switching as provided in an embodiment of this application; Figure 7b and Figure 7c A schematic diagram of the message format provided for the implementation of this application; Figure 8Another flowchart for roaming switching provided in an embodiment of this application; Figure 9 , Figure 10 and Figure 11 A schematic diagram illustrating the message format provided in an embodiment of this application; Figure 12 and Figure 13 This is a schematic diagram of the device provided in an embodiment of this application. Detailed Implementation

[0054] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings. Specific operating methods, functional descriptions, etc., in the method embodiments can also be applied to the device embodiments or system embodiments.

[0055] The embodiments of this application can be applied to wireless local area network (WLAN) systems, and are applicable to the Institute of Electrical and Electronics Engineers (IEEE) 802.11 series protocols used in WLANs, such as 802.11be, 802.11bf, and future 802.11 protocols. The method provided in this application can be implemented by a communication device in a wireless communication system or by chips or circuits applied in the communication device. Accordingly, the communication device supports communication using the IEEE 802.11 series protocols. Although the embodiments of this application are mainly illustrated using a network deploying IEEE 802.11 as an example, those skilled in the art will readily understand that the various aspects involved in the embodiments of this application can be extended to other networks employing various standards or protocols, such as Bluetooth, high-performance radio LAN (HIPERLAN) (a wireless standard similar to IEEE 802.11, mainly used in Europe), wide area network (WAN), WLAN, personal area network (PAN), or other networks now known or to be developed in the future. The technical solutions of the embodiments of this application can be applied to various cellular communication systems, such as 5th generation (5G) systems, new radio (NR) systems, and future 6th generation (6G) systems.

[0056] In IEEE 802.11 Next Generation Wireless Fidelity (Wi-Fi) Extremely High Throughput (EHT), multi-link technology can be used to improve transmission rates. Devices with multi-link aggregation capabilities are called multi-link devices (MLDs). In one design, an MLD can refer to a device that simultaneously has multiple radio frequency modules, each operating on different frequency bands / channels. When the channel spacing between two radio frequency modules within a device is sufficiently large, they can operate independently without interference. If any two links support simultaneous transmission on one link and reception on the other, then the two links are said to support simultaneous transmit and receive (STR) capability; otherwise, they are said to not support simultaneous transmit and receive capability, i.e., non-STR.

[0057] MLDs can include non-access point (non-AP) MLDs and / or access point (AP) MLDs, where non-AP MLDs can also be called station (STA) MLDs. Non-AP MLDs and AP MLDs can communicate with each other. Figure 1 As shown, MLDs (such as AP MLDs or non-AP MLDs) can include a physical layer (PHY) (such as... Figure 1 The diagram shows PHY#1, PHY#2, and PHY#n, and the medium access control (MAC) layer. The physical layer processes physical layer signals, and the MAC layer processes MAC layer signals. Furthermore, the MAC layer can be further divided into a higher MAC (UMAC) layer (e.g., ...). Figure 1 The high MAC layer shown) and multiple low-MAC (LMAC) layers (such as...) Figure 1 The diagram shows low MAC#1, low MAC#2 to low MAC#n. Figure 1As shown, multiple APs in an AP MLD operate independently at the low MAC layer and PHY, sharing the high MAC layer. Similarly, multiple STAs in a non-AP MLD operate independently at the low MAC layer and PHY, sharing the high MAC layer. The high MAC layer is connected to multiple low MAC layers, meaning it is shared by multiple links. For example, the high MAC layer primarily handles the allocation of sequence numbers (SN) and packet numbers (PN) for MAC service data units (MSDUs), as well as encryption and decryption operations. For example, the low MAC layers primarily handle the assembly of MAC protocol data units (MPDUs) for their respective links, channel access, packet transmission, and reception acknowledgment.

[0058] exist Figure 1 In an AP MLD, the PHY#1 layer, low MAC#1 layer, and high MAC layer can be considered as AP#1, the PHY#2 layer, low MAC#2 layer, and high MAC layer can be considered as AP#2, ..., the PHY#n layer, low MAC#n layer, and high MAC layer can be considered as AP#n. This means the AP MLD can be understood as containing n AP entities. In a non-AP MLD, the situation is similar; the high MAC layer is also shared by multiple links. The PHY#1 layer, low MAC#1 layer, and high MAC layer are considered as STA#1, the PHY#2 layer, low MAC#2 layer, and high MAC layer are considered as STA#2, ..., the PHY#n layer, low MAC#n layer, and high MAC layer are considered as STA#n. This means the non-AP MLD can be understood as containing n STA entities. For example... Figure 1 As shown, PHY#1 of AP#1 in the AP MLD and PHY#1 of STA#1 in the non-AP MLD operate on the same channel. AP#1 in the AP MLD and STA#1 in the non-AP MLD are connected via a link (such as...). Figure 1 The link shown (#1) enables communication; PHY#2 of AP#2 in the AP MLD and PHY#2 of STA#2 in the non-AP MLD operate on another identical channel, and AP#2 in the AP MLD and STA#2 in the non-AP MLD communicate via a link (such as...). Figure 1 The link shown (#2) enables communication; the PHY#n of AP#n in the AP MLD and the PHY#n of STA#n in the non-AP MLD operate on another identical channel, and the AP#n in the AP MLD and the STA#n in the non-AP MLD communicate via a link (such as...). Figure 1 The link shown (#n) enables communication.

[0059] In this embodiment, a non-AP MLD may experience a handover of its associated AP MLD due to factors such as movement. For example, due to the movement of a non-AP MLD, it may move from the coverage area of ​​AP MLD1 to the coverage area of ​​AP MLD2. Therefore, it may be necessary to switch the AP MLD associated with the non-AP MLD. In one design, when a non-AP MLD switches, it first disconnects the old link with the current AP MLD and then establishes 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 handover process. In the solution of this embodiment, 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. Then, at some point in time, the non-AP MLD disconnects the first transmission link with the current AP MLD. During the handover process, the non-AP MLD utilizes multi-link capabilities to transmit data simultaneously with both the current AP MLD and the target AP MLD. Because the non-AP MLD always has a transmission link throughout the entire handover process, there is no possibility of a complete interruption of the transmission link, which reduces the risk of speed drop during the handover process.

[0060] In the scheme provided in this application embodiment, during the handover or roaming process of a non-AP MLD, when dual-connectivity transmission is enabled, for downlink transmission, the current AP MLD and the non-AP MLD use a first key negotiated between them to encrypt and decrypt the uplink and / or downlink data transmitted between them. The target AP MLD and the non-AP MLD use a second key negotiated between them to encrypt and decrypt the uplink and / or downlink data transmitted between them.

[0061] like Figure 2 As shown, a communication system is provided, which includes a non-AP MLD and an AP MLD.

[0062] In the embodiments of this application, a non-AP MLD can be a device with wireless transceiver capabilities. For example, a non-AP MLD can be a terminal device, user equipment (UE), access terminal, subscriber unit, user station, mobile station, remote station, remote terminal, mobile device, user terminal, wireless communication device, user agent, or user device. In specific applications, a non-AP MLD can be a cellular phone, mobile phone, tablet computer, wearable device, point of sale (POS) machine, customer-premises equipment (CPE), computer with wireless transceiver capabilities, virtual reality (VR) terminal, augmented reality (AR) terminal, terminal device in industrial control, terminal device in self-driving, terminal device in remote medical care, terminal device in smart grid, terminal device in smart city, terminal device in smart home, etc.

[0063] In this application example, the non-AP MLD may include multiple links, each corresponding to a different STA entity. These STA entities operate independently at the low MAC and PHY layers but share the high MAC layer. These multiple STA entities typically operate on different frequency bands or channels. Figure 2 In the example, the non-AP MLD includes two STA entities, referred to as STA1 and STA2. Both STA1 and STA2 can operate in the 2.4G and 5G frequency bands, but at any given time, STA1 and STA2 are operating in different frequency bands.

[0064] AP MLD can be Figure 2 APMLD1 and / or APMLD2. In this embodiment, AP MLD is a device such as a wireless hub or router used to provide wireless network access services, and can serve as an access point for a non-AP MLD to enter the wired Ethernet backbone.

[0065] Similar to non-AP MLDs, AP MLDs can include multiple links, each corresponding to a different AP entity. These AP entities operate independently at the lower MAC and PHY layers but share the higher MAC layer. These multiple AP entities typically operate on different frequency bands or channels. Figure 2 In the example, AP MLD1 and AP MLD2 each include two AP entities, referred to as AP1 and AP2 respectively. AP1 and AP2 operate on different frequency bands; AP1 operates in the 2.4 GHz band, and AP2 operates in the 5 GHz band.

[0066] In one design, before handover or roaming, the non-AP MLD is associated with AP MLD1, and AP MLD1 is referred to as the current APMLD. See details. Figure 2 STA1 operates in the 2.4 GHz band and establishes a link with AP1. STA2 operates in the 5 GHz band and establishes a link with AP2.

[0067] Due to factors such as movement, a non-AP MLD moves out of the coverage area of ​​the current AP MLD (AP MLD1) and into the coverage area of ​​the target AP MLD (AP MLD2). During handover or roaming, the non-AP MLD establishes transmission links with both the current AP MLD (AP MLD1) and the target AP MLD (AP MLD2). For details, see [link to documentation]. Figure 2 During handover or roaming, STA2 in a non-AP MLD can disconnect its link from AP2 in the current AP MLD and establish a link with AP1 in the target AP MLD. As previously mentioned, the two STAs in a non-AP MLD can operate in the 2.4GHz or 5GHz frequency band. Figure 2 In the example, STA2 operates in the 2.4GHz band and establishes a link with AP1 in the target STA MLD.

[0068] At some point in time, a non-AP MLD can be completely switched from the current AP MLD to the target AP MLD. Figure 2 In the example, STA1 of a non-AP MLD will disconnect from the current AP MLD, and its STA1 will establish a link with one of the APs in the target AP MLD. Figure 2 In the example, STA1 disconnects from the current AP MLD, STA1 operates in the 5GHz band, and establishes a link with AP2 in the target AP MLD.

[0069] like Figure 2 As shown, after the handover or roaming of the non-AP MLD ends, the non-AP MLD connects to 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.

[0070] In one possible implementation, Figure 2 The communication system shown may also include other non-AP MLDs and / or AP MLDs, or other devices, 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). That is, the DS can construct an ESS that includes multiple interconnected BSSs, or it can be described as: the DS includes multiple interconnected BSSs, etc. BSSs are a basic component of a local area network (LAN) 802.11. A BSS consists of STAs located within a certain coverage area and forming some kind of connection. For example, an AP MLD may include multiple AP entities, each AP entity corresponds to a BSS, and each BSS corresponding to an AP entity may include at least one STA, and these multiple STAs are associated with the AP entity corresponding to that BSS. Before handover or roaming: During downlink data transmission, the DS can forward downlink data to the current AP MLD, which then sends the downlink data to the non-AP MLD. During uplink data transmission, the non-AP MLD can send uplink data to the current AP MLD, which then delivers the uplink data to the DS. After handover or roaming: During downlink data transmission, the DS can forward downlink data to the target AP MLD, which then sends the downlink data to the non-AP MLD. During uplink data transmission, the non-AP MLD can send uplink data to the target AP MLD, which then delivers the uplink data to the DS. During handover or roaming, a transmission link is established between the non-AP MLD and both the current and target AP MLDs. The processes of uplink and downlink data transmission are explained below. In one possible implementation... Figure 2 The application scenarios shown are for illustrative purposes only and are not intended to limit the embodiments of this application.

[0071] It should be noted that in the following description, during downlink and uplink data transmission, a first transmission link exists between the non-AP MLD and the current AP MLD, and a second transmission link exists between the non-AP MLD and the target AP MLD. Before roaming or handover, a first transmission link has already been established between the non-AP MLD and the current AP MLD. During roaming or handover, a second transmission link can be established between the non-AP MLD and the target AP MLD; the process of establishing the second transmission link is described later. It should be pointed out that in the embodiments of this application, the handover or roaming of the non-AP MLD can also be referred to as a BSS transfer of the non-AP MLD. The current AP MLD can be referred to as the non-AP MLD before the BSS transfer, and the target AP MLD can be referred to as the non-AP MLD after the BSS transfer, etc. The key negotiated between the current AP MLD and the non-AP MLD is called the first key. The key negotiated between the target AP MLD and the non-AP MLD is called the second key. In one implementation, the first or second key can be a pairwise transient key (PTK), etc., without restriction.

[0072] Downlink data transmission

[0073] In one design, during downlink data transmission, the current AP MLD receives third downlink data sent by the DS. The high MAC layer of the current AP MLD processes the third downlink data to obtain first downlink data, and sends the first downlink data to the target AP MLD. The high MAC layer processing does not include encrypting the third downlink data using a first key. An illustrative explanation of the high MAC layer processing is provided below. The target AP MLD uses a second key to encrypt the first downlink data to obtain second downlink data, and then sends the second downlink data to the non-AP MLD. Correspondingly, the non-AP MLD decrypts the second downlink data using the second key.

[0074] like Figure 3 As shown, a process applicable to downlink data transmission is provided, including: Step 300: The current AP MLD receives the third downlink data sent by DS.

[0075] In this embodiment, the DS can store a mapping relationship between non-AP MLDs and the current AP MLD, and a data path exists between the DS and the current AP MLD. When the DS receives third downlink data, the destination address of the third downlink data can be the address of the non-AP MLD. The DS can determine the association between the non-AP MLD and the current AP MLD based on the stored mapping relationship. Therefore, the DS forwards the third downlink data to the current AP MLD. Alternatively, the third downlink data may be downlink data to be sent by the current AP MLD. Therefore, step 300 is one implementation method and is not necessarily required.

[0076] Step 301: The current AP MLD processes the third downlink data at the high MAC layer to obtain the first downlink data. The high MAC layer processing does not include encrypting the third downlink data.

[0077] In a design, such as Figure 4 As shown, the current AP MLD can assign a sequence number (SNassignment) and a packet sequence number (PN) to the third downlink data, and the third downlink data with assigned SN and PN is referred to as the first downlink data, which includes the assigned SN and PN. In one implementation, the high MAC processing includes at least one of the following: assigning SN, assigning PN, or encryption. In one description, the current AP MLD can perform high MAC layer processing on the third downlink data other than encryption, and the processed downlink data is referred to as the first downlink data. Subsequently, the target AP MLD performs high MAC encryption processing on the downlink data. Specifically, during the encryption process, the target AP MLD can use a second key to encrypt the downlink data.

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

[0079] In one design, step 302 can be described as: the current AP MLD transparently transmits the first downlink data to the target AP MLD. For example, data transmission between the current AP MLD and the target AP MLD 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.

[0080] Step 303: The target AP MLD uses the second key to encrypt the first downlink data to obtain the second downlink data.

[0081] In one design, step 303 can be described as follows: The target AP MLD can perform high-MAC layer encryption processing on the first downlink data. During the encryption process, the target AP MLD uses a second key to encrypt the first downlink data. In one implementation, the target AP MLD can also perform low-MAC layer and physical layer processing on the first downlink data. In one design, the downlink data that has undergone encryption, low-MAC layer, and physical layer processing can be referred to as the second downlink data. In step 304, the target AP MLD can send the second downlink data to the non-AP MLD.

[0082] Step 304: The target AP MLD sends the second downlink data to the non-AP MLD.

[0083] For example, a second transmission link can be established between the target AP MLD and the non-AP MLD. The target AP MLD can send 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.

[0084] For example, such as Figure 4 As shown, for the downlink data sender: the current AP MLD can receive the third downlink data forwarded by the DS. The current AP MLD can perform processing such as SN and PN allocation on the third downlink data to obtain the first downlink data. The current AP MLD sends the first downlink data to the target AP MLD, which performs encryption, low MAC layer, and physical layer processing on the first downlink data to obtain the second downlink data. In one implementation, the high MAC layer processing includes SN allocation, PN allocation, and encryption. In this embodiment, the current AP MLD performs SN and PN allocation operations on the downlink data, and the target AP MLD encrypts the downlink data. In one description, it can be considered as splitting the high MAC layer processing function. During the downlink data processing, the current AP MLD performs SN and PN allocation operations, and the target AP MLD performs encryption operations.

[0085] like Figure 4As shown, in one implementation, encryption at the high MAC layer can be referred to as MPDU encryption. Low MAC layer processing includes: creating a cyclic redundancy check (CRC) in the MPDU header and / or A-MPDU aggregation, etc. The interface between the low MAC layer and the physical layer in the current AP MLD or target AP MLD can be called the physical layer service access point (SAP). The current AP MLD or target AP MLD can send data processed by the low MAC layer to the physical layer via the physical layer SAP. Figure 4 The example provided did not elaborate on the specific processing procedures at the physical layer.

[0086] Step 305: The non-AP MLD uses the second key to decrypt the second downlink data.

[0087] In the scenario of this application embodiment, 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 and second transmission links each have independent physical layers and low MAC layers, and these two transmission links share a high MAC layer. Specifically, when the non-AP MLD receives second downlink data from the target AP MLD, it processes the second downlink data using the physical layer and low MAC layer corresponding to the non-AP MLD (e.g., using the physical layer and low MAC layer corresponding to the target AP MLD within the non-AP MLD), and the processed data is submitted to the shared high MAC layer. During the processing at the high MAC layer, the non-AP MLD can decrypt the second downlink data using a second key. Further, in this application example, the non-AP MLD can also receive downlink data sent by the current AP MLD, which can be referred to as fourth downlink data. For example, in one implementation, when the DS receives downlink data from the non-AP MLD, it sends the downlink data to the current AP MLD according to the mapping relationship between the non-AP MLD and the current AP MLD. The current AP MLD sends a portion of the downlink data to the target AP MLD, which then sends the downlink data to the non-AP MLD. This process is called... Figure 3 The data processing steps within the workflow. Figure 3In the process, the downlink data sent from the target AP MLD to the non-AP MLD is called the second downlink data. On the other hand, the current AP MLD can also directly send downlink data to the non-AP MLD; this downlink data can be called the fourth downlink data. The processing of downlink data by the current AP MLD may include: assigning a serial number (SN), assigning a passphrase (PN), and encrypting the downlink data using the first key. When the non-AP MLD receives the fourth downlink data, it can decrypt it using the first key.

[0088] For example, the processing flow for receiving downlink data: Figure 4 As shown, the non-AP MLD includes two protocol stacks: 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 MAC layer protocol stack. When the non-AP MLD receives the second downlink data sent by the target AP MLD, it can use the physical layer and low MAC layer corresponding to the target AP MLD to process the second downlink data and submit the processed second downlink data to the shared high MAC layer. When the non-AP MLD receives the fourth downlink data from the current AP MLD, it can use the physical layer and low MAC layer corresponding to the current AP MLD to process the fourth downlink data and submit the processed fourth downlink data to the shared high MAC layer. The non-AP MLD performs high MAC layer processing on the second and fourth downlink data. It should be noted that in the high MAC layer processing, the non-AP MLD uses the first key to decrypt the second downlink data and the second key to decrypt the fourth downlink data.

[0089] In one implementation, for the receiving end of downlink data: such as Figure 4As shown, the low MAC layer processing of a non-AP MLD includes, but is not limited to, at least one of the following: A-MPDU de-aggregation, MPDU heard CRC validation, address 1 address filter, or block acknowledgment scoring. The high MAC layer processing of a non-AP MLD includes, but is not limited to, at least one of the following: block acknowledgment scoring, duplicate detection per SN, MPDU decryption, block acknowledgment buffering and reordering per SN, or replay detection per PN. It should be noted that in... Figure 4 The high MAC includes two MPDU decryptions: the MPDU decryption corresponding to the current AP MLD (which is decrypted using the first key) and the MPDU decryption corresponding to the target AP MLD (which is decrypted using the second key).

[0090] It should be noted that in this embodiment, the non-AP MLD has two transmission links: a first transmission link connected to the current AP MLD and a second transmission link connected to the target AP MLD. Before the handover, or before the end of roaming, the DS stores the mapping relationship between the non-AP MLD and the current AP MLD. During downlink transmission, when the DS receives downlink data destined for the non-AP MLD, it sends the downlink data to the current AP MLD according to the aforementioned mapping relationship between the non-AP MLD and the 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 a portion of the downlink data to the non-AP MLD through the first transmission link. The other portion of the downlink data is transparently transmitted to the target AP MLD through the DS. The target AP MLD sends the other portion of the downlink data to the non-AP MLD through the second transmission link. 3. The current AP MLD transparently transmits all downlink data to the target AP MLD through the DS. The target AP MLD sends all downlink data to the non-AP MLD via a second transmission link. Figure 3The process is described in detail as follows: When the current AP MLD receives downlink data from the DS, it transparently transmits the downlink data to the target AP MLD through the DS. The target AP MLD then sends the downlink data to the non-APMLD. In one possible implementation, in... Figure 3 In the process, the current AP MLD can pass all downlink data received from the DS through the DS to the target AP MLD. Or, in Figure 3 In this process, the current AP MLD receives a portion of the downlink data from the DS and sends it to the non-AP MLD via the first transmission link. The current AP MLD then transmits another portion of the downlink data received from the DS to the target AP MLD via the DS. The target AP MLD then sends the remaining portion of the downlink data to the non-AP MLD via the second transmission link. This division of downlink data into two parts, transmitted via different transmission links to the non-AP MLD, improves downlink data transmission speed. Furthermore, in another scenario, the current AP MLD copies the downlink data received from the DS. One copy is transmitted to the non-AP MLD via the first transmission link, while the other copy is transmitted to the target AP MLD via the DS. The target AP MLD then sends the downlink data to the non-AP MLD via the second transmission link, thus improving downlink data transmission reliability. Alternatively, the current AP MLD can send all or part of its intended downlink data to the target AP MLD, which then sends the received downlink data to the non-AP MLD. In this embodiment, the source of downlink data of the current AP MLD is not limited. The focus is on the processing of downlink data by the current AP MLD and the target AP MLD when the current AP MLD sends downlink data to the target AP MLD.

[0091] Uplink data transmission

[0092] In one design, during uplink data transmission, the non-AP MLD establishes two transmission links: a first transmission link with the current AP MLD and a second transmission link with the target AP MLD. Before handover, or before the end of roaming, the DS stores the mapping relationship between the current AP MLD and the non-AP MLD. For the DS to correctly process uplink data, the non-AP needs to deliver the uplink data to the current AP MLD, which then delivers the uplink data to the DS. The non-AP MLD delivers the uplink data to the current AP MLD in several ways, including but not limited to the following: 1. The non-AP MLD delivers uplink data to the current AP MLD through the first transmission link.

[0093] 2. The non-AP MLD delivers a portion of the uplink data to the current AP MLD. The non-AP MLD then delivers the other portion of the uplink data to the target AP MLD. The target AP MLD then forwards this other portion of the uplink data to the current AP MLD via the DS. Dividing the uplink data into two parts and transmitting them to the current AP MLD through different links can improve the uplink data transmission rate.

[0094] 3. The non-AP MLD delivers all uplink data to the target AP MLD. The target AP MLD then forwards all uplink data to the current AP MLD via DS.

[0095] 4. A non-AP MLD can duplicate uplink data into two copies: one copy is sent directly to the current AP MLD via the first transmission link, and the other copy is sent to the target AP MLD via the second transmission link. The target AP MLD then forwards the uplink data to the current AP MLD via the DS. By transmitting the same uplink data through two transmission links, the reliability of uplink data transmission can be improved.

[0096] In methods 2, 3, and 4 described above, the following process is involved: the non-AP MLD sends uplink data to the target AP MLD, and the target AP MLD passes the uplink data through the DS to the current AP MLD. In one possible implementation, methods 1 to 4 described above are merely illustrative and are not intended to limit the uplink data transmission scenario in this application.

[0097] In the uplink data transmission process provided in this embodiment, when the non-AP MLD sends uplink data to the target AP MLD, it encrypts the uplink data using a second key negotiated between the non-AP MLD and the target AP MLD. Upon receiving the uplink data, the target AP MLD decrypts the uplink data using the second key and sends the decrypted data to the current AP MLD. The current AP MLD then delivers the complete uplink data to the DS in sequence. Figure 5 As shown, a process applicable to uplink data transmission is provided, including: Step 500: The non-AP MLD uses the second key to encrypt the uplink data to be transmitted, thus determining the first uplink data.

[0098] For a non-AP MLD, there are two protocol stacks: one for the current AP MLD and one for the target AP MLD. The current AP MLD and the target MLD share the allocation SN and allocation PN. The current AP MLD and the target AP each have their own encryption, low MAC layer, and physical layer. In one design, the high MAC layer includes the allocation SN, allocation PN, and encryption. In current designs, the protocol stacks of the target AP MLD and the current AP MLD share the high MAC layer. However, in the embodiments of this application, the protocol stacks of the target AP MLD and the current AP MLD each have independent encryption. For example, such as... Figure 6 As shown, the data to be transmitted by the non-AP undergoes shared processing such as SN allocation and PN allocation in sequence. Then, the non-AP MLD encrypts the data to be transmitted according to the MLD of the target AP. During the encryption process, a second key is used to encrypt the downlink data to be transmitted. Figure 6 In the example, the encryption is called MPDU encryption. Then, the data to be transmitted undergoes low-MAC layer and physical layer processing to obtain the first data. Figure 6 In the example, the processing at the lower MAC layer includes: creating the CRC (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, where the uplink data undergoes further physical layer processing. After physical layer processing, the uplink data is then sent to the target AP MLD via the second transmission link.

[0099] Step 501: The non-AP MLD sends the first uplink data to the target AP MLD.

[0100] Step 502: The target AP MLD uses the second key to decrypt the first uplink data and obtain the second uplink data.

[0101] In one design, when the target AP MLD receives the first uplink data, it can perform physical layer and low MAC layer processing on the first uplink data. Regarding the physical layer processing, in... Figure 6 Not specified. Figure 6In the example, the low MAC layer processing includes, but is not limited to, at least one of the following: A-MPDU de-aggregation, MPDU header CRC validation, address 1 address filter, or block acknowledgment scoring. The target AP MLD decrypts the first uplink data, using a second key during the decryption process. Figure 6 In the example, decryption is referred to as MPDU decryption.

[0102] Step 503: The target AP MLD sends the second uplink data to the current AP MLD.

[0103] Step 504: The current AP MLD performs high MAC layer processing on the second uplink data to obtain the third uplink data. The high MAC layer processing does not include decryption of the third uplink data.

[0104] In one design, the processing of the high MAC layer includes at least one of the following: block acknowledgment scoring, duplicate detection per SN, MPDU decryption, block acknowledgment buffering and reordering per SN, or replay detection per PN, etc.

[0105] In this embodiment, the high MAC layer block acknowledgment scoreboard and MPDU decryption can be implemented on the target AP MLD side. That is, one implementation of step 502 is: the target AP MLD performs high MAC layer processing on the first uplink data, which includes block acknowledgment scoreboard and MPDU decryption, etc.

[0106] For high MAC layer processing, such as per-SN duplicate detection, block acknowledgment buffering and SN reordering, or per-PN replay detection, these processes can be implemented on the target AP MLD side. In other words, one implementation of step 504 includes: the current AP MLD performing high MAC layer processing on the second uplink data, which includes per-SN duplicate detection, block acknowledgment buffering and SN reordering, or per-PN replay detection.

[0107] It should be noted that, in this embodiment, during normal high MAC layer processing, per-SN duplicate detection is implemented before MPDU decryption. In this embodiment, MPDU decryption is implemented before per-SN duplicate detection. Furthermore, the MPDU decryption function is implemented in the target AP MLD, while per-SN duplicate detection is implemented in the current AP MLD. This design is primarily based on the following considerations: Besides receiving uplink data packets sent by the non-AP MLD through the target AP MLD, the current AP MLD can also directly receive uplink data packets from the non-AP MLD. During SN duplicate detection, the current AP MLD needs to acquire all uplink data before performing SN duplicate detection. For example, SN duplicate detection can also be referred to as duplicate detection.

[0108] Step 505: The current AP MLD sends the third uplink data to the DS.

[0109] In one design, the current AP MLD can send the third uplink data to the DS, which then processes or applies it. Alternatively, the third uplink data can be sent to the current AP MLD, which can directly process or apply it. 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 executed. Therefore, step 505 is optional.

[0110] In one possible implementation, Figure 5 In the process: besides sending uplink data to the current AP MLD using steps 500 to 504 as described above, the non-AP MLD can also directly send uplink data to the current AP MLD. In this process, the non-AP MLD encrypts the uplink data using the first key. Correspondingly, when the current AP MLD receives the uplink data, it decrypts the uplink data using the first key. For example, in one description: the non-AP MLD encrypts the uplink data to be transmitted using the first key to obtain the fourth uplink data. For example, in one implementation, such as... Figure 6 As shown, the non-AP MLD can utilize shared allocation SN and allocation PN, etc., to process the uplink data to be transmitted. Then, the non-AP MLD uses the current AP MLD's independent MPDU encryption, low MAC layer, and physical layer, etc., to process the uplink data to be transmitted, obtaining the fourth uplink data. The first key is used to encrypt the uplink data to be transmitted in the MPDU encryption. Correspondingly, when the current AP MLD receives the fourth uplink data, it can process the data of the fourth data sequentially through the physical layer, low MAC layer, and high MAC layer, etc. Regarding... Figure 6For the current AP MLD side, the division between the low MAC layer and the high MAC layer can be found in the previous description of the target AP MLD side.

[0111] This application also provides a process for establishing a second transmission link between a non-AP MLD and a target AP MLD. For example, a first transmission link exists between the non-AP MLD and the current AP MLD. In one implementation, the first transmission link can be considered a data connection between the non-AP MLD and the current AP MLD. A data path exists between the current AP MLD and the DS, and the DS stores a mapping relationship between the non-AP MLD and the current AP MLD. The current AP MLD detects 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. In this case, the current AP MLD can allow the non-AP MLD to perform beacon measurements. Based on the beacon measurement results reported by the non-AP MLD, the current AP MLD recommends an AP MLD to switch to. The non-AP MLD selects one of the recommended AP MLDs as the target AP MLD. In one implementation, the non-AP MLD reports its selected target AP MLD to the current AP MLD. In another implementation, the current AP MLD can send a seventh request to the non-AP MLD, which includes second indication information. This second indication information instructs the non-AP MLD to retain the non-AP MLD's BA session information and / or context information, and to cache any data not yet sent by the non-AP MLD. Upon receiving the second indication information, the non-AP MLD may retain the BA session information and / or context information during subsequent exploratory shutdowns. In another implementation, the non-AP MLD can send a seventh response to the current AP MLD, which is a response to the seventh request. In one implementation, the seventh request can be a BSS transition management (BTM) request frame, and the seventh response can be a BTM response frame.

[0112] [Tentative Connection]

[0113] A non-AP MLD can tentatively associate with a target AP MLD through an affiliated STA. During this tentative association process, the non-AP MLD can establish a second transmission link with the target AP MLD. Furthermore, they can negotiate transmission capability parameters (e.g., transmission bandwidth and maximum number of streams), key information (e.g., PTK, group temporal key (GTK), integrity group temporal key (IGTK), and beacon integrity group temporal key (BIGTK), etc.), and resource allocation information (e.g., BA session, restricted target wakeup time (r-TWT) establishment, etc.).

[0114] In one design, a non-AP MLD can send a first request to a target AP MLD, requesting 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, which is a response to the first request. For example, the non-AP MLD can send a first request to the target AP MLD to request the establishment of a second transmission link. Upon receiving the first request, the target AP MLD can send a first response to the non-AP MLD, indicating that the target AP MLD agrees to establish the second transmission link and indicating at least one of the following: transmission capability parameters, key information, or resource allocation information of both. The target AP MLD sends a first response to the non-AP MLD, which may include at least one of the negotiated transmission capability parameters, key information, or resource allocation information of both.

[0115] In one implementation, the first request can be a reassociation request frame, used by the non-AP MLD to initiate an exploratory association with the target AP MLD. The first response can be a reassociation response frame, used to establish the exploratory association between the non-AP MLD and the target AP MLD. During the exploratory association process, the non-AP MLD and the target AP MLD can establish a second transmission link and negotiate various parameters.

[0116] It should be noted that during the exploratory association process: the target AP MLD does not refresh the mapping relationship between the non-AP MLD and the current AP MLD stored on the DS side. Before sending the first request (such as the reassociation request frame mentioned above), the non-AP MLD will not delete the first key negotiated with the current AP MLD, nor will it clear the transmit buffer and receive buffer. The non-AP MLD still maintains the first transmission link with the current AP MLD. Through the first transmission link, the non-AP MLD and the current AP MLD can still exchange uplink and / or downlink data.

[0117] In one implementation, the first request may include indication information to enable dual-link transmission for the non-AP MLD. The dual links include 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. After receiving the indication information and successfully establishing the second transmission link, the target AP MLD will initiate dual-link transmission negotiation with the current AP MLD to enable dual-link transmission.

[0118] Dual-link transmission

[0119] During dual-link roaming, data needs to be transmitted between the current AP MLD and the target AP MLD. Therefore, when the target AP MLD receives an instruction from the non-AP MLD to enable dual-link transmission via a first request, it can send a second request to the current AP MLD. This second request requests the activation of dual-link transmission for the non-AP MLD. In downlink transmission, the current AP MLD can send the downlink data from the non-AP MLD to the target AP MLD. The target AP MLD encrypts the downlink data using a second key and sends the encrypted data to the non-AP MLD. In uplink transmission, the target AP MLD receives uplink data from the non-AP MLD, decrypts the uplink data using the second key, and sends the decrypted uplink data to the current AP MLD. The current AP MLD then sends the uplink data to the DS. For details, please refer to the sections on "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, which is a response to the second request. For example, the second response may include indications of whether the current AP MLD agrees to enable dual-link transmission.

[0120] In one design, dual-link transmission during roaming can be described as roaming transmission based on a dual-active protocol stack (DAPS). DAPS-based roaming transmission refers to a non-AP MLD with multi-link simultaneous transmission and reception being able to simultaneously perform uplink and / or downlink transmissions with both the current AP MLD and the target AP MLD during roaming. For example, the second request can be a DAPS enable request, and the second response can be a DAPS enable response.

[0121] In one possible implementation, data transmission between the target AP MLD and the current AP MLD can be forwarded through the DS. In this embodiment, it is not limited whether the DS performs any processing and / or operations on the data during forwarding. If the DS does not perform any processing or operations on the data, it can be referred to as transparent transmission by the DS. In one design, the current AP MLD can encapsulate data in a special frame or message and transmit it transparently to the target AP MLD through the DS. In another possible implementation, "transparent transmission" in the relevant descriptions of this embodiment can also be replaced with descriptions such as sending or forwarding. If the DS performs corresponding operations and / or processing on the received data during data forwarding, this is also within the scope of protection of this embodiment. Alternatively, data can be directly transmitted between the target AP MLD and the current AP MLD, without limitation.

[0122] [Data Path Switching]

[0123] A non-AP MLD can trigger a data path switch, 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 switch, the non-AP MLD will use a second key negotiated with the target AP MLD to encrypt and / or decrypt uplink and / or downlink data. In one implementation, the second key can be a PTK.

[0124] In one implementation, this application embodiment does not restrict the conditions for triggering data path switching for non-AP MLDs. For example, a non-AP MLD can trigger data path switching when a first condition is met. This first condition includes, but is not limited to, the link quality of the optimal link of the target AP MLD being higher than the link quality of the optimal link of the current AP MLD.

[0125] It should be noted that during roaming, the non-AP MLD uses both the first and second transmission links simultaneously for data transmission. At the end of roaming, the non-AP MLD can perform a data path switch. In one description, during the data path switch, the non-AP MLD will disconnect the first transmission link and utilize the second transmission link entirely for data transmission. Alternatively, in another description, as described above... Figure 2 As can be seen from the example, in dual-link transmission, the non-AP MLD uses different STA entities to establish transmission links with both the current AP MLD and the target AP MLD. For example, as... Figure 2 The description states that during roaming: STA1 (a non-AP STA) establishes a first transmission link with the current AP MLD, and STA2 (a non-AP MLD) establishes a second transmission link with the target AP MLD. During data path switching, the essence is that STA1 disconnects its first transmission link with the current AP MLD, and STA1 establishes another transmission link with the target AP MLD.

[0126] In one design, during the path switching process triggered by a non-AP MLD: the non-AP MLD can send a third request to the target AP MLD, which requests the triggering of a path switch for the non-AP MLD (e.g., a data path switch). In one implementation, the target AP MLD can send a third response to the non-AP MLD, which can be a response to the third request. For example, the third response may include indications of whether or not the path switch is agreed upon. If the target AP MLD agrees to the path switch, it can send a fourth request to the DS, which requests the DS to update its stored mapping between the non-AP MLD and the current AP MLD to a mapping between the non-AP MLD and the target AP MLD. In one implementation, the DS can send a fourth response to the target AP MLD, which can be a response to the fourth request. In another implementation, the fourth response may include indications of whether or not the DS agrees to update the mapping. Alternatively, the target AP MLD can send an uplink data packet to the DS via MAC SAP. Based on the information that the uplink data packet can carry non-AP MLD, DS automatically updates its stored mapping relationship, etc.

[0127] 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 notification request for updating or adding new features, and the fourth response can be a DS-STA notification response.

[0128] Furthermore, after the target AP MLD receives the third request and before the target AP MLD sends the fourth request to the DS, the process further includes: the target AP MLD sending a context transfer request to the current AP MLD; and the target AP MLD receiving a context transfer response from the current AP MLD, wherein the context transfer response includes the context information of the non-AP MLD.

[0129] In one implementation, the context transfer response further includes at least one of the following: a block acknowledgment protocol for the traffic identifier (TID), the starting position of the window of the TID's transmit buffer, the window size of the TID's transmit buffer, the starting position of the window of the uplink receiver scoreboard, the window size of the uplink receiver scoreboard, the starting position of the window of the receive reordering buffer, the window size of the receive reordering buffer, the currently received maximum packet sequence number PN value, or an uplink replay counter.

[0130] In one design: the target AP MLD receives a third request from the non-AP MLD, which requests 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 before sending a fourth request to the DS to refresh the mapping relationship stored on the DS side. This ensures that uplink delivery is not out of order. The reason is as follows: before refreshing the mapping relationship stored on the DS side, uplink data is delivered to the DS through the current AP MLD. At the instant when the non-AP MLD's transmission path switches from the first transmission path to the second transmission path, that is, when the target AP MLD receives the context transfer response from the current AP MLD, there may be a situation where the uplink data delivered by the current AP MLD to the DS has not yet been processed. Therefore, in this embodiment, when the target AP MLD receives the context transfer response from the current AP MLD, it waits for a period of time. During this time, the DS finishes processing the uplink data of the current AP MLD before sending a fourth request to refresh the mapping relationship to the DS. Alternatively, before sending a context transfer response, the current AP MLD needs to ensure that all its uplink data has been successfully delivered to the DS. For example, in one implementation, after sending a sixth request to the DS to delete the mapping between the non-AP MLD and the current AP MLD, the current AP MLD then sends a context transfer response to the target AP MLD. See the description below for the sixth request.

[0131] In one implementation, when a non-AP MLD determines that a path switching has been triggered, the non-AP MLD may send a fifth request to the current AP MLD. The current AP MLD receives the fifth request sent by the non-AP MLD, and the fifth request is used to request the termination of 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 another implementation, the fifth request includes first indication information, which instructs the current AP MLD to retain the BA information and / or context information of the non-AP MLD and to cache data not sent by the non-AP MLD. After receiving the fifth request, the current AP MLD sends a 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. Upon receiving the sixth request, the DS may delete the mapping relationship between the non-AP MLD and the current AP MLD stored therein. Alternatively, in one implementation, the current AP MLD can proactively trigger a BSS transfer in the non-AP MLD. For example, the current AP MLD can proactively trigger the non-AP MLD to switch to the target AP MLD. In this case, the current AP MLD can send a fifth request to the non-AP MLD, which is used to sever the association between the current AP MLD and the non-AP MLD.

[0132] In one implementation, the fifth request may be a disassociation frame, and the sixth request may be a DS-STA-NOTIFY.request for deletion.

[0133] In one design, the non-AP MLD may not send the fifth request to the current AP MLD. In this case, after the current AP MLD receives the context transfer request from the target AP MLD but has not received the fifth request from the non-AP MLD, the current AP MLD can stop submitting uplink data to the DS. The current AP MLD then sends a sixth request to the DS, requesting the deletion of the mapping between the non-AP MLD and the current AP MLD stored in the DS. Afterward, the current AP MLD sends a context transfer response to the target AP MLD.

[0134] It should be noted that, as explained above: the target AP MLD can send a fourth request to the DS, which requests the DS to update the stored mapping between non-AP MLDs and the current AP MLD to a mapping between non-AP MLDs and the target AP MLD. However, as also explained above: the current AP MLD can send a sixth request to the DS, which requests the deletion of the stored mapping between non-AP MLDs and the current AP MLD. In one design, the DS first receives the sixth request and deletes its stored mapping between non-AP MLDs and the current AP MLD. Then, the DS receives the fourth request, which adds the mapping between non-AP MLDs and the target AP MLD to its storage. In other words, the update mapping in the fourth request above can also represent adding the mapping between non-AP MLDs and the target AP MLD. Alternatively, upon receiving the fourth request, the DS can directly update its stored mapping relationships. For example, it can replace the stored mapping relationship between the non-AP MLD and the current AP MLD with the mapping relationship between the non-AP MLD and the target AP MLD. In this case, the current AP MLD no longer needs to send a sixth request to the AP MLD to delete the mapping relationship.

[0135] On the DS side, after receiving the fourth request from the target AP MLD, the DS can switch the data path. For example, the DS can delete the data path between the non-AP MLD and the current AP MLD, or add a data path between the non-AP MLD and the target AP MLD. After successfully sending a context transfer response, the current AP MLD can release the context of the non-AP MLD.

[0136] In this embodiment, the current AP MLD also needs to send downlink and / or uplink data that meets the following conditions to the target AP MLD. For example, in one design, the current AP MLD can send the downlink and / or uplink data described below to the target AP MLD when it receives a context transfer request from the target AP MLD. The downlink and / or uplink data described below can be carried in the context transfer response. Alternatively, the current AP MLD can send the uplink and / or downlink data described below to the target AP MLD before or after sending the context transfer response to the target AP MLD, without limitation.

[0137] For example, for downlink data transmission, the current AP MLD needs to forward (unencrypted) downlink data to the target AP MLD, carrying an end marker in the last downlink data. One implementation is that the downlink data format can be MSDU or MPDU. For MPDU formatted downlink data, the "more data" field in the MPDU header can be reused. For example, when the MPDU is the last downlink data, the "more data" field is set to the first value; otherwise, it is set to the second value. One implementation is that the first value can be 0, and the second value can 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 sends it to the non-AP MLD.

[0138] For example, for uplink data transmission, the current AP MLD can forward the uplink receive buffer, which has been processed by a higher MAC layer (e.g., decrypted MSDU or MPDU), to the target AP MLD. The target AP MLD then sends the received complete and continuous uplink data to the DS, etc.

[0139] In one design, when a non-AP MLD switches over, it first disconnects the old link with the current AP MLD and then establishes a new link with the target AP MLD. Before establishing the new link with the target AP MLD, the non-AP MLD clears its transmit and receive buffers, resulting in packet loss. The receive buffer stores discontinuous data received by the non-AP MLD, and the transmit buffer stores data that the non-AP MLD has not sent or that has been sent but not acknowledged by the receiver. In the scheme of this application embodiment, the non-AP MLD first establishes a second transmission link with the target AP MLD. During this period, neither the non-AP MLD nor the current AP MLD clears its transmit and receive buffers; they still transmit data, thus avoiding packet loss. Then, at some point, the non-AP MLD disconnects the first transmission link with the current AP MLD and transfers the transmission session or block acknowledgment (BA) session to the target AP MLD. During the handover process, the non-AP MLD utilizes multi-link capabilities to simultaneously transmit data with both the current AP MLD and the target AP MLD, reducing the risk of speed drops during the handover process.

[0140] Example 1

[0141] In this embodiment, a second transmission link is directly established between the non-AP MLD and the target AP. The first request and / or the third request mentioned above are transmitted via the air interface between the non-AP MLD and the target AP MLD. Figure 7a The diagram illustrates a process. It should be noted that during execution... Figure 7a Before the process begins: a first transmission link exists between the non-AP MLD and the current AP MLD. For example, a data connection exists between the non-AP MLD and the current AP MLD. A data path exists 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. For example... Figure 7a As shown, the process includes: Step 701: The current AP MLD detects a deterioration in the link quality of the non-AP MLD and sends a beacon measurement request to the non-AP MLD.

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

[0143] Step 703: Based on the beacon measurement report, the current AP MLD recommends that the non-AP MLD switch to a neighboring AP MLD. 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 of the recommended AP MLDs as the target AP MLD.

[0144] In one implementation, the BTM request frame includes second indication information, which instructs the non-AP MLD to retain the BA information and / or context information of the non-AP MLD and to cache data not sent by the non-AP MLD. Upon receiving the second indication information, the non-AP MLD can initiate DAPS-based dual-link roaming.

[0145] One implementation may further include, before the current AP MLD sends a BTM request frame to the non-AP MLD, the non-AP MLD sending a BTM query frame to the current AP MLD. Upon receiving the BTM query frame, the current AP MLD then sends a BTM request frame to itself.

[0146] 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.

[0147] Step 705: The non-AP MLD initiates an exploratory association with the target AP MLD. During this exploratory association process, the following steps can be performed: establishing a second transmission link between the target AP MLD and the non-AP MLD, including the bandwidth and maximum number of supported streams of the second transmission link; establishing a BA session; and negotiating a key, which includes a second key for communication between the two.

[0148] In one implementation, a tentative association can be established between the non-AP MLD and the target AP MLD via a reassociation request frame and a reassociation response frame. For details on the reassociation request frame and reassociation response frame, please refer to the explanation of the first request and first response above. In another possible implementation, during the tentative association process, the mapping relationship between the non-AP MLD and the AP MLD stored on the DS side is not refreshed. Instead, the mapping relationship between the non-AP MLD and the current AP MLD is stored on the DS side. When the DS receives downlink data from the non-AP MLD, it will deliver it to the current AP MLD.

[0149] Step 706: After the non-AP MLD and the target AP MLD complete the tentative association, the target AP MLD and the current AP MLD can start DAPS roaming through the interaction of DAPS enable request and DAPS enable response.

[0150] For information on the DAPS enable request and DAPS usage response, please refer to the explanation of the second request and second response above.

[0151] Step 707: The non-AP MLD triggers a path switch. The non-AP MLD sends a STA-AP mapping request frame to the target AP MLD. This STA-AP request frame can be used to request the target AP MLD to perform a path switch. For details on the STA-AP mapping request frame, please refer to the third request section above.

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

[0153] Step 709: The current AP MLD sends a context transfer response to the target AP MLD. For details regarding the content carried in the context transfer response, please refer to the previous explanation.

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

[0155] Upon receiving the aforementioned DS-STA notification request, the DS updates its stored mapping relationship from the mapping between the non-AP MLD and the current AP MLD to a mapping between the non-AP MLD and the target AP MLD. The DS then disconnects the data path from the current AP MLD and establishes a data path with the target AP MLD. For details on the DS-STA notification request, please refer to the explanation in the fourth request section above.

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

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

[0158] The non-AP MLD and the target AP MLD can use a negotiated second key to encrypt and / or decrypt uplink and / or downlink data.

[0159] In one implementation, step 707, when the non-AP MLD determines that a path switching has been triggered, further includes: the non-AP MLD sending a cancellation frame to the current AP MLD; the cancellation frame can be found in the fifth request section above. The current AP MLD may send a DS-STA-notify request to the DS for deletion. The DS deletes its stored mapping relationship between the non-AP MLD and the current AP MLD.

[0160] In this embodiment, the transmission between the current AP MLD and the target AP MLD is transparently transmitted through the DS. In this embodiment, 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 descriptions of "Uplink Data Transmission" and "Downlink Data Transmission" above.

[0161] In one design, the information and / or data transmitted between the AP MLD and the target AP MLD can adopt the following frame format. For example... Figure 7b As shown, the frame format includes at least one of the following fields: Destination MAC address: A MAC address that can carry 48 bits.

[0162] Source MAC address: A MAC address that can carry 48 bits.

[0163] Length field; The logical link control (LLC) field includes: the destination service access point (DSAP) address (this field is fixed as AA), the destination service access point (SSAP) address (this field is fixed as AA), and the control field (fixed as 0x03).

[0164] The Subnetwork Access Protocol (SNAP) field includes: the Organizationally Unique Identifier field and the Ethernet Type field.

[0165] Payload type field: This field can be set to one or more preset values ​​depending on the payload.

[0166] Payload field: For example, the payload field can carry DAPS enable requests, DAPS enable responses, context transfer requests, context transfer responses, or uplink / downlink data that needs to be transparently transmitted, as mentioned above. This payload field can also carry MPDUs that conform to the tunneling 802.11 protocol.

[0167] It should be noted that when the current AP MLD and the target AP MLD pass-through uplink / downlink data, the information carried in the payload field can be constructed using the additional authentication data (AAD) of the cipher-block chaining message authentication code protocol (CCMP), and includes the CCMP header and the encrypted frame body. In one design, such as... Figure 7cAs shown, the payload field includes at least one of the following fields: frame control, address1, address2, address3, sequence control, quality of service (QoS) control, CCMP header, or frame body.

[0168] In one implementation, the load 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. Furthermore, when the load field includes the above fields, the specific values ​​of these fields can be set to empty.

[0169] In Example 1, during non-AP MLD handover or roaming, the non-AP MLD utilizes multi-link capabilities to establish dual links with both the current AP MLD and the target AP MLD, enabling simultaneous data transmission using both AP MLDs and improving transmission rate and reliability during roaming. Furthermore, since the non-AP MLD does not disconnect its first transmission link with the current AP MLD or clear its transmit and receive buffers during roaming, the probability of packet loss and / or interruption during roaming is reduced.

[0170]

Example 2

[0171] In this embodiment, 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 mentioned above 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, through the pass-through of the DS, sends the first request and / or the third request to the target AP MLD.

[0172] For non-AP MLDs, there is another important device type: the enhanced multi-link single radio (EMLSR) non-AP MLD. In one design, an EMLSR non-AP MLD refers to a device with multiple receive radio chains capable of simultaneously detecting multiple links. When an initial control frame is received from an AP MLD, the radio chains of other links in the EMLSR link set can be switched to the corresponding link that received the initial control frame, thereby increasing the number of transmit and receive streams. That is, at any given time, an EMLSR non-AP MLD can only select one link for data transmission and reception. Because an EMLSR non-AP MLD has only one fully functional transceiver compared to a multi-radio non-AP MLD, with the rest being low-cost, feature-limited units (because they can only receive specific initial control frames), its cost is much lower, but its performance is significantly lower than that of a multi-radio non-AP MLD. Since an EMLSR non-AP MLD can only transmit and receive data on a single link... When using the scheme in Embodiment 1 to tentatively associate with the target AP MLD, it needs to switch to the corresponding channel of the target AP MLD for the tentative association operation. This will cause data transmission interruption between it and the current AP MLD, severely affecting its roaming performance. Therefore, Embodiment 2 proposes a scheme that can further improve the roaming performance of non-AP MLDs, especially the roaming performance of non-AP MLDs with single radio links and EMLSR non-AP MLDs.

[0173] like Figure 8 As shown, a process is provided. During execution... Figure 8 Before the process, a first transmission link is established between the non-AP MLD and the current AP MLD. This first transmission link is also called the data connection between the current AP MLD and the non-AP MLD. A data path exists between the DS and the current AP MLD. 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: Step 801: The current AP MLD detects a deterioration in the link quality of the non-AP MLD and sends a beacon measurement request to the non-AP MLD.

[0174] Step 802: The non-AP MLD performs beacon measurements and sends a beacon measurement report back to the current AP MLD.

[0175] Step 803: Based on the beacon measurement report, the current AP MLD recommends that the non-AP MLD switch to a neighboring AP MLD. 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 of the recommended AP MLDs as the target AP MLD.

[0176] One implementation may further include, before the current AP MLD sends a BTM request frame to the non-AP MLD, the non-AP MLD sending a BTM query frame to the current AP MLD. Upon receiving the BTM query frame, the current AP MLD then sends a BTM request frame to itself.

[0177] 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.

[0178] Step 805: The non-AP MLD is tentatively associated with the target AP MLD. The tentative association can be a DS-based tentative reassociation.

[0179] To ensure uninterrupted data transmission between the non-AP MLD and the target AP MLD during exploratory association operations, an over-the-DS (DS) exploratory association method is defined. This means the non-AP MLD can perform exploratory association operations with the target AP MLD through the current AP MLD. For example, a non-AP can send a first request to the current AP MLD, requesting the establishment of a second transmission link between the non-AP MLD and the target AP MLD. Upon receiving the first request, the current AP MLD forwards it to the target AP MLD via the DS. The target AP MLD can then establish a second transmission link between itself and the non-AP MLD based on the first request. This second transmission link can be an air interface link between the non-AP MLD and the target AP MLD. In one implementation, the target AP MLD can send a first response to the current AP MLD via the DS. The current AP MLD then sends the first response to the non-AP MLD. In another implementation, the first request and first response can be a fast BSS transition (FT) probe request and an FT probe response, respectively.

[0180] 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), thus saving the signaling overhead of the first request.

[0181] The non-AP MLD sends an eighth request to the current AP MLD. The current AP MLD then forwards the eighth request to the target AP MLD via the DS. The eighth request requests communication parameters from the target AP MLD. The target AP MLD sends an eighth response to the current AP MLD via the DS. The current AP MLD then sends an eighth response to the non-AP MLD. The eighth response includes a second key negotiated between the non-AP MLD and the target AP MLD. In one implementation, the eighth request and the eighth response can be an FT request and an FT response, respectively.

[0182] The non-AP MLD sends a ninth request to the current AP MLD. The current AP MLD forwards the ninth request to the target AP MLD via the DS. The ninth request is used to negotiate link operation parameters between the non-AP MLD and the target AP MLD. The target AP MLD sends a ninth response to the current AP MLD via the DS. The current AP MLD sends a ninth response to the non-AP MLD, which 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 can be an FT reassociation request and an FT reassociation response, respectively.

[0183] In a design, such as Figure 9 As shown, for the FT action frames (including but not limited to FT query requests, FT query responses, FT requests, FT responses, FT reassociation requests, and FT reassociation responses mentioned above) that are transmitted between the non-AP MLD and the target AP MLD through DS and the current AP MLD, at least one of the following fields is included: category, FT action, MAC address of the non-AP MLD, MAC address of the target AP MLD, and frame body.

[0184] The category field indicates the category to which the FT action frame belongs. The FT action field includes the value corresponding to the FT action; different FT action frames have different values ​​for this field. For example, as shown in Table 1: Table 1

[0185] It can be seen that when Figure 9 When a FT action frame is used as an FT reassociation request, the value of this FT action field is set to 7. Figure 9 When the middle row frame is used as an FT reassociation response, the FT action field is set to 8. This can be used for FT query requests, FT query responses, FT requests, and FT responses mentioned earlier. Figure 9 The format of the FT action frame is different; simply set the FT action field value in Table 1 to the corresponding value.

[0186] The non-AP MLD field includes the MAC layer address of the non-AP MLD. Specifically, it can be either the high MAC layer address or the low MAC layer address of the non-AP MLD, etc., without restriction. The target AP MLD's MAC address includes the target AP MLD's MAC layer address, which can be either the high MAC layer address or the low MAC layer address of the target AP MLD, etc.

[0187] The frame body field is used to carry the frame body corresponding to the FT action frame.

[0188] In one implementation, the FT reassociation request frame, as shown in Table 2, carries at least one of the following pieces of information in its frame body.

[0189] Table 2: Information carried in the frame body of FT reassociation request frames

[0190] In one implementation, as shown in Table 3, the frame body of the FT reassociation response carries at least one of the following information: Table 3: Information carried in the frame body of the FT reassociation response frame

[0191] In one embodiment of this application, when the FT reassociation request and FT reassociation response are transmitted via DS, one implementation method is as follows: 1. The frame body of the FT reassociation request and / or FT reassociation response does not need to carry the OCI. The OCI is mainly used for channel information verification, thereby reducing the signaling overhead of the FT reassociation request and / or FT reassociation response.

[0192] 2. After the current AP MLD and the target AP MLD conduct an exploratory association using FT reassociation request and FT reassociation response, the initial state of the second transmission link established between the non-AP MLD and the target AP MLD is power saving mode, and its state is power saving (doze) state.

[0193] 3. The mobility domain element (MDE) in the frame body of the FT reassociation request and / or FT reassociation response carries a 1-bit indication information, which is used to indicate whether OS-based (over-the-DS) tentative association is supported.

[0194] Step 806: The non-AP MLD triggers a path switch. The non-AP MLD sends a STA-AP mapping request frame to the target AP MLD. This STA-AP request frame can be used to request the target AP MLD to perform a path switch. For details on the STA-AP mapping request frame, please refer to the third request section above.

[0195] As mentioned above Figure 7a The process is not in the middle, in Figure 8 In the process, in step 806: the non-AP MLD sends a STA-AP mapping request frame to the target AP MLD, including: the non-AP MLD sending a STA-AP mapping request frame to the current AP MLD. The current AP MLD sends the STA-AP mapping request frame to the target AP MLD through the pass-through of the DS.

[0196] Step 807: The target AP MLD sends a context transfer request to the current AP MLD.

[0197] Step 808: The current AP MLD sends a context transfer response to the target AP MLD. For details regarding the content carried in the context transfer response, please refer to the previous explanation.

[0198] Step 809: The target AP MLD sends a DS-STA-Notification Request to the DS.

[0199] Upon receiving the aforementioned DS-STA notification request, the DS updates its stored mapping relationship from the mapping between the non-AP MLD and the current AP MLD to a mapping between the non-AP MLD and the target AP MLD. The DS then disconnects the data path from the current AP MLD and establishes a data path with the target AP MLD. For details on the DS-STA notification request, please refer to the explanation in the fourth request section above.

[0200] Step 8010: The current AP MLD deletes the context of the non-AP MLD.

[0201] In one implementation, in step 806, when the non-AP MLD determines that a path switching has been triggered, it can also send a deassociation frame to the current AP MLD. For details on this deassociation frame, please refer to the fifth request mentioned above. The current AP MLD can send a DS-STA-notify request to the DS for deletion. The DS deletes its stored mapping relationship between the non-AP MLD and the current AP MLD.

[0202] It should be noted that, in Figure 8 In the process, before roaming or handover, a first transmission link exists between the non-AP MLD and the current AP MLD. During roaming or handover, a second transmission link can be established between the non-AP MLD and the target AP MLD via the DS and / or the current AP MLD's pass-through. This second transmission link includes: non-AP MLD—target AP MLD. After roaming or handover ends, the non-AP MLD and the target AP MLD use the second transmission link for uplink and / or downlink data transmission. In one design, after step 8011, i.e., after the target AP MLD sends a STA-AP mapping response frame to the non-AP MLD, the target AP MLD and the non-AP MLD use the second transmission link for uplink and / or downlink data transmission. The target AP MLD and the non-AP MLD use a second key negotiated by both parties to encrypt and decrypt uplink and / or downlink data, and the corresponding data is transmitted in the second transmission link.

[0203] It should be noted that, in the preceding description of this application, the solution of Embodiment Two was introduced for single-radio non-AP MLDs and / or EMLSR type non-AP MLDs. In one possible implementation, the solution of Embodiment Two is not limited to only the above two types of non-AP MLDs. For example, the solution provided in Embodiment Two can also be used for non-AP MLDs that can simultaneously transmit and receive data with multiple AP MLDs, and there is no limitation.

[0204] In the second embodiment, the non-AP MLD is not limited to having the ability to send and receive data with multiple AP MLDs at the same time. It is also applicable to non-AP MLDs that can only transmit data with one AP MLD at a certain time, further improving the roaming performance of non-AP MLDs, especially improving the roaming performance of non-AP MLDs with a single Radio link and EMLSR non-APMLDs.

[0205]

Example 3

[0206] In the aforementioned 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 a beacon measurement request, it can perform beacon measurements on each link of the non-AP. In one design, the non-AP MLD can 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. The non-AP MLD only reports the link quality of the current link to the current AP MLD if the link quality of the current link is greater than or equal to the link quality of the link corresponding to the serving AP; otherwise, it does not report the link quality of the corresponding link. This design mainly considers the following: the non-AP MLD reports the link quality of the measured links 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 links it reports. If the link quality of a certain link is lower than that of the link corresponding to the serving AP, then the link is considered to have poor link quality and is not suitable as the target AP MLD for handover. In this case, the non-AP MLD does not need to report the beacon measurement results of the link with poor quality, thereby reducing the overhead of reporting beacon measurement results.

[0207] In one implementation, the current AP MLD can send a radio measurement request frame to the non-AP MLD via a certain link. Upon receiving the radio measurement request frame, the non-AP MLD can perform corresponding measurements on the non-AP MLD's link and send a radio measurement report frame to the current AP MLD, which includes the measurement results measured by the non-AP MLD.

[0208] In a design, such as Figure 10 As shown, a wireless measurement request frame includes at least one of the following fields: category, radio measurement action, dialog token, number of repetitions, or measurement request elements.

[0209] The category field indicates which category the corresponding wireless measurement request frame belongs to. For example, the wireless measurement request frame could be a frame related to wireless measurement or a frame related to roaming.

[0210] Wireless measurement action: This can be used to indicate the type of the wireless measurement request. For example, a wireless measurement action can indicate whether the corresponding frame is a request frame or a measurement frame. Of course, in the embodiments of this application, Figure 10 The wireless measurement request frame shown is used to request a non-AP MLD to perform wireless measurements. In this case, the type of the frame indicating the wireless measurement action is a request frame.

[0211] Dialogue token: Used to identify the correspondence between a request frame and a response frame. In one implementation, the response frame may also use... Figure 10 The format shown. A pair of request and response frames carries the same dialog token value.

[0212] Number of repetitions: Indicates the number of times the wireless measurement will be repeated. For example, a repetition count of 0 indicates that non-AP MLD does not require repeated measurements and only needs to be measured once. Alternatively, a repetition count of 65535 indicates that non-AP MLD requires repeated measurements until the measurement is cancelled. This repetition count field is one implementation method, i.e. Figure 10 The frame format shown may not include a repetition count field.

[0213] Measurement Request Element: Used to request beacon measurements or indicate the received signal strength indication (RSSI) of a channel. In one design, when the measurement request element instructs the non-AP MLD to perform RSSI measurements, the non-AP MLD can report the RSSI of the measured link to the current AP MLD. That is, in Embodiments 1 and 2 above, the current AP MLD, in addition to requesting the non-AP MLD to perform beacon measurements, can also request the non-AP MLD to report the RSSI of the links it is measuring. Alternatively, when the measurement request element instructs the non-AP MLD to perform beacon measurements, the non-AP MLD can jump to the channel of the link to be measured and send a probe request. The current AP MLD 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 can directly listen for beacon frames on the link to be measured. The non-AP MLD determines the link quality of the corresponding link based on the listened-for beacon frames.

[0214] Furthermore, in Figure 10 In the frame format, when the measurement request element instructs the non-AP MLD to perform beacon measurements, Figure 10 The frame may also include a beacon reporting subelement. In one implementation, the beacon reporting subelement includes a reporting condition field and / or a threshold / offset reference field. In one design, when the value of the reporting condition field is set to a first value, which includes, but is not limited to, 7, it indicates that if the difference between the received signal-to-noise ratio (SNR) of the corresponding link measured by the non-AP MLD and the received SNR of the current serving AP is greater than or equal to the value in the aforementioned threshold / offset reference field, then the beacon measurement result is reported to the current AP MLD; otherwise, the beacon measurement result is not reported to the current AP.

[0215] In one design, under a multi-link scenario, the current AP MLD can send a beacon measurement request to the non-AP MLD through any affiliated AP with a link to it. In this case, the non-AP MLD may have ambiguity regarding the serving AP. The non-AP MLD cannot definitively determine which AP to use for the aforementioned received signal-to-noise ratio (SNR) comparison. To address this issue, the following solution is proposed: Option 1: In Figure 10The frame format shown includes, in addition to the reporting condition field and / or threshold / offset reference field, a link ID field, which can be referenced. Figure 11 As shown. This link identifier field indicates the link corresponding to the serving AP. Furthermore, in addition to the link identifier field, it also includes a reserved field. This field can be called the link ID info field. The link identifier field can occupy 4 bits, and the reserved field can occupy 4 bits. Alternatively, in Figure 10 The frame format shown includes a multi-link operation (MLO) link information subelement. For example... Figure 11 As shown, this segment includes: element ID, length, element ID extension, and link ID bitmap.

[0216] Option 2: Restrict the links on which the current AP MLD sends beacon measurement requests, and designate the AP corresponding to the link that sends the beacon measurement request as the serving AP. That is, for the non-AP MLD side, the AP corresponding to the link on which it receives the beacon measurement request is designated as the serving AP.

[0217] Using the above method, non-AP MLD can report beacon measurement results that meet the conditions, which reduces the reporting overhead compared to reporting beacon measurement results for all links.

[0218] It should be noted that, in the embodiments of this application: 1. Focus on describing the differences between the different processes; the descriptions of different processes can be used for cross-referencing.

[0219] 2. In Figure 3 , Figure 5 , Figure 7a and Figure 8 In the process, there are no restrictions on the order in which different steps are executed.

[0220] 3. In Figure 3 , Figure 5 , Figure 7a and Figure 8 The process can include more steps or fewer steps than a flowchart or text description, without limitation.

[0221] In the embodiments provided above, the methods provided by the embodiments of this application are described from the perspective of interaction between various devices. To implement the methods provided by the embodiments of this application, non-AP MLD, current AP MLD, and target APMLD may include hardware structures and / or software modules, and the above functions can be implemented in the form of hardware structures, software modules, or a combination of hardware structures and software modules. Whether a particular function is executed in the form of hardware structures, software modules, or a combination of hardware structures and software modules depends on the design constraints of the specific application of the technical solution.

[0222] Figure 12 and Figure 13 The diagram illustrates the possible structures of devices provided in embodiments of this application. These communication devices can implement one or more corresponding functions as described in the above method embodiments. For example, functions implemented by a target AP MLD, a current AP MLD, or a non-AP MLD, thus potentially achieving the beneficial effects of the above method embodiments.

[0223] like Figure 12 As shown, the communication device 1200 includes a processing unit 1210 and a transceiver unit 1220.

[0224] For example, the processing unit 1210 may also be referred to as a processor, processing board, processing module, processing device, etc. The transceiver unit 1220 may also be referred to as a transceiver, transceiver module, transceiver device, 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 they may be two independent units, etc.

[0225] In one design, the communication device 1200 is used to implement Figure 3 The specific functions of the target AP MLD are as follows: a transceiver unit 1220 is used to receive the first downlink data sent by the current AP MLD; a processing unit 1210 is used to encrypt the first downlink data using a second key to obtain the second downlink data, wherein the second key is a key negotiated between the target 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 transceiver unit 1220 is also used to send the second downlink data to the non-AP MLD.

[0226] In one design, the communication device 1200 is used to implement Figure 3 The current functions of AP MLD are as follows: Transceiver unit 1220 is used to receive third downlink data sent by the distributed system DS; processing unit 1210 is used for... The third downlink data is processed by the High Media Access Control (MAC) layer to obtain the first downlink data. The high MAC layer processing does not include encrypting the third downlink data. The transceiver unit 1220 is also used to send the first downlink data to the target AP MLD, which is a non-access point (non-AP MLD) after the basic service set (BSS) transfer.

[0227] In one design, the 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 second downlink data sent by a target access point AP MLD, where the target AP MLD is the AP MLD after the non-AP MLD is transferred to the Basic Service Set (BSS); a processing unit 1210 is used to decrypt the second downlink data using a second key to obtain fourth downlink data, where the second key is a key negotiated between the target AP MLD and the non-AP MLD; the transceiver unit 1220 is also used to receive fifth downlink data sent by the current AP MLD; the processing unit 1210 is also used to decrypt the fifth downlink data using a first key to obtain sixth downlink data, where the first key is a key negotiated between the current AP MLD and the non-AP MLD.

[0228] In one design, the communication device 1200 is used to implement Figure 5 The specific functions of the target AP MLD are as follows: The transceiver unit 1220 is used to receive first uplink data sent by a non-access point (non-AP MLD); the processing unit 1210 is used to decrypt the first uplink data using a second key to obtain second uplink data, wherein the second key is a key negotiated between the target 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 transceiver unit 1220 is used to send the second uplink data to the current AP MLD.

[0229] In one design, the communication device 1200 is used to implement Figure 5 The current functions of AP MLD are as follows: Transceiver unit 1220 receives second uplink data sent by a target AP MLD. The second uplink data is data decrypted using a second key, which is a key negotiated between the target AP MLD and a non-AP MLD. The target AP MLD is the AP MLD after the non-AP MLD is transferred to the Basic Service Set (BSS). Processing unit 1210 performs high media access control (MAC) layer processing on the second uplink data to obtain third uplink data. The high MAC layer processing does not include decrypting the second uplink data. Transceiver unit 1220 sends the uplink data to the distributed system (DS).

[0230] In one design, the communication device 1200 is used to implement Figure 5 The functions of non-AP MLD are as follows: Processing unit 1210 is used to encrypt the uplink data to be transmitted using a second key to obtain first uplink data, wherein the second key is a key negotiated between the target access point (AP MLD) and the non-AP MLD; transceiver unit 1220 is used to send the first uplink data to the target AP MLD; processing unit 1210 is used to encrypt the uplink data to be transmitted using the first key to obtain fourth uplink data, wherein the first key is a key negotiated between the current AP MLD and the non-AP MLD; transceiver unit 1220 is used to send the fourth uplink data to the current AP MLD, wherein the target AP MLD is the AP MLD after the non-AP MLD is transferred to the Basic Service Set (BSS).

[0231] For a more detailed description of the processing unit 1210 and the transceiver unit 1220, please refer to the above method embodiments. Figure 3 or Figure 5 The description is omitted here.

[0232] The division of units in this embodiment is illustrative and represents only one logical functional division. In actual implementation, other division methods may be used. Furthermore, the functional units in this embodiment may be integrated into a single physical device (e.g., a processor), or each functional unit may be a separate physical device. Alternatively, two or more units may be integrated into a single unit. The integrated unit may be implemented in hardware or as a software functional module, etc.

[0233] Figure 13 A schematic diagram of another structure of the communication device 1300 provided in an embodiment of this application is shown. For example, Figure 13 The communication device 1300 shown can be Figure 12The following describes one implementation of the hardware circuit of the communication device 1200 shown. For ease of explanation, Figure 13 Only the main parts of the communication device are shown.

[0234] like Figure 13 As 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.

[0235] For example, processor 1310 can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. A general-purpose processor can be a microprocessor or any conventional processor. Interface circuit 1320 can be a transceiver or input / output circuit, etc.

[0236] Optionally, the communication device 1300 may also 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 code.

[0237] For example, memory 1330 may be in random access memory (RAM), flash memory, read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), register, hard disk, portable hard disk, CD-ROM, or any other form of storage medium known in the art.

[0238] When the communication device 1300 is used to implement Figure 3 or Figure 5 When the method is to select the target AP MLD, the current AP MLD, or the non-AP MLD, 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.

[0239] In one design, interface circuit 1320 is used to receive signals from other communication devices besides communication device 1300 and transmit them to processor 1310, or to send signals from processor 1310 to other communication devices besides communication device 1300. Processor 1310 implements the above through logic circuits or executed code instructions. Figure 3 or Figure 5 The function of the target AP MLD, the current AP MLD, or the non-AP MLD.

[0240] This application embodiment also provides a communication device, which includes a processor and a memory, the processor and the memory being coupled, the processor being used to implement... Figure 3 or Figure 5 The function of the target AP MLD, the current AP MLD, or the non-AP MLD. For example, the processor can execute instructions in memory to cause the communication device to perform one or more of the functions described in the above method embodiments, such as by... Figure 3 or Figure 5 The middle is composed of the target AP MLD, the current AP MLD, or the non-AP MLD.

[0241] The functions implemented include... One example is that a storage medium is coupled to a processor, enabling the processor to read information from and write information to the storage medium. Of course, the storage medium can also be a component of the processor. The processor and storage medium can reside within an ASIC. Furthermore, the ASIC can be located in... Figure 3 or Figure 5 The target AP MLD, the current AP MLD, or the non-AP MLD can be used. The processor and storage media can also exist as discrete components. Figure 3 or Figure 5 The target AP MLD, current AP MLD, or non-AP MLD are among them.

[0242] This application also provides a computer-readable storage medium storing instructions, which may also be referred to as computer programs, computer program code, etc. The instructions are executed on a computer, causing the computer to perform the methods described in the above embodiments. Figure 3 or Figure 5 The function of the target AP MLD, the current AP MLD, or the non-AP MLD.

[0243] Optionally, the computer may be a general-purpose computer, a special-purpose computer, a computer network, a network device, a user equipment, or other programmable device. The computer program or instructions may be stored in a computer-readable storage medium or transferred from one computer-readable storage medium to another. For example, the computer program or instructions may be transferred from one website, computer, server, or data center to another website, computer, server, or data center via wired or wireless means. The computer-readable storage medium may be any available medium that a computer can access, 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, hard disk, or magnetic tape; or an optical medium, such as a digital video optical disc; or a semiconductor medium, such as a solid-state drive. 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.

[0244] This application also provides a computer program product, including a computer program or instructions, which, when run on a computer, cause the above-mentioned... Figure 3 or Figure 5 The method for the target AP MLD, the current AP MLD, or the non-AP MLD is executed. For example, a computer program product includes one or more computer programs or instructions. When the computer program or instructions are loaded and executed on a computer, all or part of the embodiments of this application are performed. Figure 3 or Figure 5 The process or function of the target APMLD, the current AP MLD, or the non-AP MLD.

[0245] The methods in the embodiments of this application can be implemented, in whole or in part, by software, hardware, firmware, or any other combination thereof. When implemented in software, they can be implemented, in whole or in part, in the form of a computer program product.

[0246] This application also provides a chip, which includes a processor coupled to a memory. The processor is used to execute computer programs or instructions stored in the memory, enabling the chip to achieve... Figure 3 or Figure 5 The function of the target AP MLD, the current AP MLD, or the non-AP MLD.

[0247] This application also provides a communication system, including: a first communication device, a second communication device, and a third communication device.

[0248] The first communication device can achieve the aforementioned Figure 3 or Figure 5The target AP MLD function is described above. The second communication device can achieve the functions described above. Figure 3 or Figure 5 The current AP MLD functionality. The third communication device can implement the functions described above. Figure 3 or Figure 5 The function of the non-AP MLD. For the specific structure of the first, second, or third communication device, please refer to the preceding description, for example... Figure 12 or Figure 13 The structure is explained in the text.

[0249] 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 relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, or B exists alone, where A and B can be singular or plural. In the textual description of this application, the character " / " generally indicates that the preceding and following related objects have 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.

[0250] The various numerical designations used in the embodiments of this application are merely for descriptive convenience and are not intended to limit the scope of the embodiments of this application. The order of the process numbers described above does not imply 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 the first downlink data sent by the current AP MLD; The target AP MLD uses a second key to encrypt the first downlink data to obtain the second downlink data. The second key is the key negotiated between the target AP MLD and the non-AP MLD, where the target AP MLD is the AP MLD after the non-AP MLD is transferred to the Basic Service Set (BSS). The target AP MLD sends the second downlink data to the non-AP MLD.

2. The method as described in claim 1, characterized in that, The first downlink data includes a sequence number SN and a packet number PN, which are assigned by the current AP MLD.

3. The method as described in claim 2, characterized in that, The current AP MLD and the target AP MLD share the SN and the PN.

4. The method according to any one of claims 1 to 3, characterized in that, The method further includes: The target AP MLD receives context information from the current AP MLD, the context information including: the block acknowledgment protocol of the service identifier TID.

5. The method as described in claim 4, characterized in that, The context information also includes: the starting position of the window of the TID's send buffer.

6. The method as described in claim 4 or 5, characterized in that, The context information also includes: an uplink replay counter.

7. The method as described in claim 1, characterized in that, A first transmission link exists between the non-AP MLD and the current AP MLD, and the method further includes: The target AP MLD receives a first request, which 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 establishes a second transmission link with the non-AP MLD.

8. The method as described in claim 7, characterized in that, The first request includes an indication to enable dual-link transmission of the non-AP MLD, wherein the dual links include the first transmission link and the second transmission link.

9. The method as described in claim 1, characterized in that, Also includes: The target AP MLD sends a second request to the current AP MLD, the second request being used to request the activation of dual-link transmission for the non-AP MLD.

10. The method as described in claim 1, characterized in that, Also includes: The target AP MLD receives a third request, which is used to request the triggering of a path switch for the non-AP MLD; The target AP MLD sends a fourth request to the distributed system DS, which requests 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.

11. The method according to any one of claims 7 to 10, characterized in that, The first request and / or the third request are sent by the non-AP MLD, and the first request and / or the third request are transmitted over the air interface between the non-AP MLD and the target AP MLD, or transmitted through the current AP MLD and DS.

12. The method as described in claim 11, characterized in that, When the first request is transmitted through the current AP MLD and DS, the first request does not include Operation Channel Information (OCI).

13. The method as described in claim 10, 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, and the context transfer response includes the context information of the non-AP MLD.

14. A communication device, characterized in that, Includes units for implementing the method of any one of claims 1 to 13.

15. A communication device, characterized in that, include: Memory, used to store program instructions; A processor for executing the program instructions, causing the communication device to perform the method as described in any one of claims 1 to 13.

16. An apparatus, characterized in that, The device includes a processor and an interface circuit, the interface circuit being used to receive signals from other devices outside the device and transmit them to the processor or to send signals from the processor to other devices outside the device, the processor causing the device to implement the method as described in any one of claims 1 to 13 through logic circuits or executing code instructions.

17. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores instructions that are executed on a computer to cause the computer to perform the method of any one of claims 1 to 13.

18. A computer program product, characterized in that, Includes a computer program or instructions that, when executed by a device, cause the method of any one of claims 1 to 13 to be performed.

19. A chip, characterized in that, The device includes a processor coupled to a memory for executing a computer program or instructions stored in the memory, such that a communication device including the chip performs the method of any one of claims 1 to 13.

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