Communication method and communication device

Abstract

Provided are a communication method and a communication device. The method comprises: a first station (STA) receives a first frame sent by a first access point (AP), wherein the first frame comprises first time information, the first time information is used for determining a first time by the first STA during roaming from a source AP to a target AP, and the first time is a time when the first STA is allowed to start communicating with the target AP. In embodiments of the present application, first time information is introduced, and can assist a first STA in deciding when to start communicating with a target AP, thereby reducing latency in a seamless roaming process and improving the reliability of the seamless roaming process.

Description

Communication method and communication device TECHNICAL FIELD

[0001] The present application relates to the technical field of communication, and more particularly, to a communication method and a communication device. BACKGROUND

[0002] In some communication systems, a station (STA) can seamlessly roam between different access points (APs) or different networks. How to improve the reliability of the roaming process is a technical problem to be solved.

[0003] SUMMARY

[0004] The present application provides a communication method and a communication device. Each aspect of the present application is described below.

[0005] In a first aspect, a communication method is provided, the method comprising: receiving, by a first station (STA), a first frame sent by a first access point (AP), the first frame comprising first time information used in a roaming process of the first STA.

[0006] In a second aspect, a communication method is provided, the method comprising: sending, by a first AP, a first frame to a first STA, the first frame comprising first time information used in a roaming process of the first STA.

[0007] In a third aspect, a communication device is provided, the communication device being a first STA, the first STA comprising: a receiving unit configured to receive a first frame sent by a first AP, the first frame comprising first time information used in a roaming process of the first STA.

[0008] In a fourth aspect, a communication device is provided, the communication device being a first AP, the first AP comprising: a sending unit configured to send a first frame to a first STA, the first frame comprising first time information used in a roaming process of the first STA.

[0009] In a fifth aspect, a communication device is provided, comprising a transceiver, a memory and a processor, the memory being configured to store one or more computer programs, and the processor being configured to invoke the computer programs in the memory, so that the communication device performs the method in the first aspect or the second aspect.

[0010] In a sixth aspect, a computer readable storage medium is provided, the computer readable storage medium storing a computer program, the computer program causing a communication device to perform the method in the first aspect or the second aspect.

[0011] In a seventh aspect, a computer program product is provided, which includes a non-transitory computer readable storage medium storing a computer program operable to cause a communication device to perform the method in the first aspect or the second aspect.

[0012] In an eighth aspect, a chip is provided, which includes a memory and a processor, the processor can invoke and run a computer program from the memory to implement the method in the first aspect or the second aspect.

[0013] The embodiments of the present application introduce first time information for the roaming process of the first STA, which can assist the first STA to decide the timing to start the communication with the target AP, thereby improving the reliability of the seamless roaming process. BRIEF DESCRIPTION OF DRAWINGS

[0014] FIG. 1 is a schematic diagram of a wireless communication system to which the embodiments of the present application are applied.

[0015] FIG. 2 is a signaling flow diagram of WIFI seamless roaming in the related art, according to an embodiment of the present application.

[0016] FIG. 3 is a signaling flow diagram of WIFI seamless roaming in the related art, according to another embodiment of the present application.

[0017] FIG. 4 is a signaling flow diagram of WIFI seamless roaming in the related art, according to another embodiment of the present application.

[0018] FIG. 5 is a signaling flow diagram of WIFI seamless roaming in the related art, according to another embodiment of the present application.

[0019] FIG. 6 is a signaling flow diagram of WIFI seamless roaming in the related art, according to another embodiment of the present application.

[0020] FIG. 7 is a signaling flow diagram of WIFI seamless roaming in the related art, according to another embodiment of the present application.

[0021] FIG. 8 is a signaling flow diagram of WIFI seamless roaming in the related art, according to another embodiment of the present application.

[0022] FIG. 9 is a signaling flow diagram of a communication method, according to an embodiment of the present application.

[0023] FIG. 10A is an example diagram of the format of a roaming preparation response frame, according to an embodiment of the present application.

[0024] FIG. 10B is an example diagram of the format of a frame body field of the roaming preparation response frame, according to an embodiment of the present application.

[0025] FIG. 11A is an example diagram of a format of a link reconfiguration notify frame according to an embodiment of the present application.

[0026] FIG. 11B is an example diagram of a format of a frame body field of the link reconfiguration notify frame according to an embodiment of the present application.

[0027] FIG. 11C is an example diagram of a format of a reconfiguration multi-link element field according to an embodiment of the present application.

[0028] FIG. 11D is an example diagram of a format of a multi-link control field in the reconfiguration multi-link element field according to an embodiment of the present application.

[0029] FIG. 11E is an example diagram of a format of a common info field in the reconfiguration multi-link element field according to an embodiment of the present application.

[0030] FIG. 11F is an example diagram of a format of a Per-STA profile sub-element of a link info field according to an embodiment of the present application.

[0031] FIG. 11G is an example diagram of a format of a STA control field according to an embodiment of the present application.

[0032] FIG. 11H shows a correspondence between encoding of a reconfiguration operation type subfield and a multi-link operation (MLO) update type according to an embodiment of the present application.

[0033] FIG. 11I is an example diagram of a format of a STA info field in the STA control field according to an embodiment of the present application.

[0034] FIG. 11J is an example diagram of a format of an operation parameter subfield according to an embodiment of the present application.

[0035] FIG. 12A is an example diagram of a format of a link reconfiguration response frame according to an embodiment of the present application.

[0036] FIG. 12B is an example diagram of a format of a frame body field of the link reconfiguration response frame according to an embodiment of the present application.

[0037] FIG. 12C is an example diagram of a format of a reconfiguration status duple according to an embodiment of the present application.

[0038] FIG. 12D is an example diagram of a format of a basic multi-link element field according to an embodiment of the present application.

[0039] FIG. 12E is an example diagram of a format of a multi-link control field in the basic multi-link element field according to an embodiment of the present application.

[0040] FIG. 12F is an example diagram of a format of a common information field in the basic multi-link element field according to an embodiment of the present application.

[0041] FIG. 12G is an example diagram of a format of a Per-STA profile sub-element of a link information field according to an embodiment of the present application.

[0042] FIG. 12H is an example diagram of a format of a STA control field in the link information field according to an embodiment of the present application.

[0043] FIG. 12I is an example diagram of a format of a STA information field in the STA control field according to an embodiment of the present application.

[0044] FIG. 13A is an example diagram of a format of a probe response frame according to an embodiment of the present application.

[0045] FIG. 13B is an example diagram of a format of a frame body field of the probe response frame according to an embodiment of the present application.

[0046] FIG. 14 is a signaling flow diagram of WIFI seamless roaming according to an embodiment of the present application.

[0047] FIG. 15 is a signaling flow diagram of WIFI seamless roaming according to another embodiment of the present application.

[0048] FIG. 16 is a signaling flow diagram of WIFI seamless roaming according to a further embodiment of the present application.

[0049] FIG. 17 is a signaling flow diagram of WIFI seamless roaming according to a still further embodiment of the present application.

[0050] FIG. 18 is a signaling flow diagram of WIFI seamless roaming according to a yet further embodiment of the present application.

[0051] FIG. 19 is a signaling flow diagram of WIFI seamless roaming according to an even further embodiment of the present application.

[0052] FIG. 20 is a schematic structural diagram of a communication device according to an embodiment of the present application.

[0053] FIG. 21 is a schematic structural diagram of a communication device according to another embodiment of the present application.

[0054] FIG. 22 is a schematic structural diagram of a communication device according to an embodiment of the present application. DETAILED DESCRIPTION

[0055] The technical solutions in the present application will be described below with reference to the accompanying drawings.

[0056] Communication system

[0057] The technical solutions of the embodiments of the present application can be applied to various communication systems, such as a wireless local area network (WLAN), a wireless fidelity (WIFI), a high performance radio local area network (HIPELAN), a wide area network (WAN), a cellular network or other communication systems, etc. For example, the technical solutions provided by the embodiments of the present application can be applied to a communication system using 802.11 standards. For example, the 802.11 standards include but are not limited to: an 802.11ax standard, an 802.11be standard, an 802.11bn standard, a post 802.11bn standard (a next generation of 802.11bn standard), etc.

[0058] FIG. 1 shows a schematic diagram of a communication system to which the embodiments of the present application are applicable. Referring to FIG. 1, the communication devices in the communication system 100 can include an access point (AP) 111, an AP 112, a station (STA) 121 and a STA 122, wherein the STA 121 can access a network through the AP 111, and the STA 122 can access a network through the AP 112.

[0059] In some implementations, a STA can establish an association relationship with one or more APs, and then the STA and the APs having the association relationship can communicate with each other. Referring to FIG. 1, the AP 111 and the STA 121 can communicate with each other after establishing an association relationship, and the AP 112 and the STA 122 can communicate with each other after establishing an association relationship.

[0060] In some implementations, the communication in the communication system 100 can be the communication between an AP and a Non-AP STA, or the communication between a Non-AP STA and a Non-AP STA, or the communication between a STA and a peer STA, where the peer STA can refer to a device that communicates with the STA, for example, the peer STA can be an AP or a Non-AP STA.

[0061] It should be understood that the communication system 100 exemplarily shows two AP STAs and two Non-AP STAs, and the communication system 100 can also include a larger number of AP STAs, or the communication system 100 can include other numbers of Non-AP STAs, and the embodiments of the present application do not limit this.

[0062] In addition, the above communication system can be applied to a multi-device cooperation scenario, such as a multi-AP (multi-access point, multi-AP) cooperation scenario, or a multi-site cooperation scenario.

[0063] In the embodiments of the present application, the names of the AP and / or the STA are not limited. In some scenarios, the AP can also be referred to as an AP STA, that is, in a certain sense, the AP is also a kind of STA. In other scenarios, the STA can also be referred to as a Non-AP STA.

[0064] In some scenarios, the above communication device can also be a multi-link device (multi-link device, MLD), that is, a device that can communicate through multiple communication links, where the multiple communication links can include communication links of different frequency bands, for example, can include millimeter wave frequency bands and / or low frequency frequency bands. Generally, if the multi-link device is an AP, the AP can also be referred to as an AP MLD. If the multi-link device is a Non-AP STA, the Non-AP STA can also be referred to as a Non-AP MLD.

[0065] In the embodiments of the present application, the AP can be a device in a wireless network. The AP can be a communication server, a router, a switch, a bridge, or the like communication entity, or the AP can include various forms of macro base stations, micro base stations, relay stations, and the like, and of course the AP can also be a chip or a circuit or a processing system in these various forms of devices, thereby implementing the methods and functions of the embodiments of the present application. The AP can be applied to various scenarios, such as a sensor node in a smart city (such as a smart water meter, a smart electricity meter, a smart air detection node), a smart device in a smart home (such as a smart camera, a projector, a display screen, a television, a sound box, a refrigerator, a washing machine, and the like), a node in the Internet of Things, an entertainment terminal (such as an AR, a VR, and the like wearable device), a smart device in a smart office (such as a printer, a projector, and the like), a vehicle networking device in vehicle networking, some infrastructure in daily life (such as a vending machine, a self-service navigation station of a supermarket, a self-service cash register device, and a self-service ordering machine), and the like.

[0066] In some implementations, the role of the STA in the communication system is not absolute, and in some scenarios, the STA can act as an AP. For example, in the scenario of a mobile phone connecting a router, the mobile phone can be a Non-AP STA, and in the case of the mobile phone acting as a hotspot for other mobile phones, the mobile phone acts as an AP.

[0067] In the embodiments of the present application, the STA in the embodiments of the present application can be a device with wireless transceiving functions, such as a device supporting 802.11 series protocols and capable of communicating with an AP or other STAs. For example, the STA is any user communication device that allows a user to communicate with an AP and thus communicate with a WLAN. The STA is, for example, a user equipment (UE), a mobile station (MS), a mobile terminal (MT), an access terminal, a subscriber unit, a subscriber station, a mobile station, a mobile terminal, a remote station, a remote terminal, a mobile device, a user terminal, a terminal, a wireless communication device, a user agent, or a user device.

[0068] The STA in the embodiments of the present application can also be a device providing voice / data / image connectivity to a user, for example, a handheld device, a vehicle-mounted device, a home device, a household appliance, a game device, etc. with wireless connection function or equipped with a wireless communication module. For example, a mobile phone, a tablet computer, a notebook computer, a palm computer, a mobile internet device (MID), a wearable device, a virtual reality (VR) device, an augmented reality (AR) device, a wireless terminal in industrial control, a wireless terminal in self driving, a drone or a flight photography device, a wireless terminal in remote medical surgery, a wireless terminal in smart grid, a wireless terminal in transportation safety, a wireless terminal in smart city, a wireless terminal in smart home, a cellular phone, a cordless phone, a session initiation protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA), a handheld device with wireless communication function, a computing device or other processing device connected to a wireless modem, a vehicle-mounted device, a wearable device, a terminal device in a 5G network or a terminal device in a future evolved public land mobile network (PLMN), etc. can also be a television, a refrigerator, a washing machine, a kitchen appliance, a door lock, a fish tank, a sweeping robot, a game machine, a camera / camcorder, etc. with wireless connection function, and the embodiments of the present application are not limited thereto.

[0069] By way of example and not limitation, in the embodiments of the present application, the STA can also be a wearable device. The wearable device can also be referred to as a wearable smart device, which is a general term for devices that are designed and developed by applying wearable technology to daily wear, such as glasses, gloves, watches, clothing, and shoes. For example, a smart watch or smart glasses, etc. and only focus on a certain type of application function, need to be used with other devices such as smart phones, such as various types of smart wristbands, smart jewelry, etc.

[0070] In addition, in the embodiments of the present application, the STA can also be a terminal device in an internet of things (IoT) system. The IoT is an important part of future information technology development, and its main technical feature is to connect objects through communication technology and network, so as to realize the intelligent network of man-machine interconnection and object-object interconnection. In the embodiments of the present application, the IoT technology can achieve massive connection, deep coverage and terminal power saving through, for example, narrow band (NB) technology.

[0071] In addition, in the embodiments of the present application, the STA can be a device in a vehicle-to-everything (V2X) system. The communication mode in the V2X system is collectively referred to as V2X (X represents anything). For example, the V2X communication includes vehicle-to-vehicle (V2V) communication, vehicle-to-infrastructure (V2I) communication, vehicle-to-pedestrian (V2P) communication or vehicle-to-network (V2N) communication, etc.

[0072] In addition, in the embodiments of the present application, the STA can also include a smart printer, a train detector, a gas station sensor, and the like. The main functions include collecting data (part of the terminal device), receiving control information and downlink data of the AP, and transmitting electromagnetic waves to transmit data to the AP.

[0073] In addition, the AP in the embodiments of the present application can be a device for communicating with the STA. The AP can be a network device in a wireless local area network, and the AP can be used for communicating with the STA through the wireless local area network.

[0074] From the perspective of the communication mode supported by the AP, in some implementation manners, the AP can be a device supporting the 802.11be mode. The AP can also be a device supporting multiple current and future WLAN modes of the 802.11 family, such as 802.11ax, 802.11ac, 802.11n, 802.11g, 802.11b and 802.11a.

[0075] From the perspective of the communication mode supported by the STA, in some implementation manners, the Non-AP STA can support the 802.11be mode. The Non-AP STA can also support multiple current and future WLAN modes of the 802.11 family, such as 802.11ax, 802.11ac, 802.11n, 802.11g, 802.11b and 802.11a.

[0076] In the embodiments of the present application, the frequency bands that can be supported by the WLAN technology are not limited. In some implementations, the frequency bands that can be supported by the WLAN technology can include, but are not limited to, low-frequency frequency bands (such as 2.4 GHz, 5 GHz, 6 GHz), high-frequency frequency bands (such as 45 GHz, 60 GHz).

[0077] It should be understood that the specific forms of the STA and the AP in the embodiments of the present application are not specially limited, and are only exemplary described herein.

[0078] In order to realize the fast switching of the STA between the APs, the related art proposes the concept of seamless roaming. There are various implementations of the seamless roaming, and the following gives several possible implementations.

[0079] Seamless roaming signaling procedure based on non-collocated AP MLD

[0080] The related art (for example, see proposal 23 / 1884r0) proposes a signaling procedure of seamless roaming based on non-collocated AP MLD.

[0081] Firstly, the signaling procedure is based on the following assumptions:

[0082] Firstly, the source AP, the target AP and the controller communicate through the backhaul;

[0083] Secondly, the context can be transmitted from the source AP to the target AP through the backhaul;

[0084] Thirdly, there is no data forwarding between the APs;

[0085] Fourthly, in the call procedure, AP1 and AP2 can be generalized to AP MLD1 and AP MLD2;

[0086] Fifthly, the STA and the non-AP MLD are synonymous in the call procedure.

[0087] In addition, in the signaling procedure of the seamless roaming based on the non-collocated AP MLD, the context that can be transferred between the APs includes the sequence number (SN) and / or the packet number (PN) corresponding to the traffic identity (TID).

[0088] In the roaming process, if the STA (or Non-AP MLD) can simultaneously communicate with multiple non-collocated APs, the signaling procedure of the seamless roaming based on the non-collocated AP MLD can be as shown in FIG. 2.

[0089] Referring to FIG. 2, at step S201, the STA requests to increase the link with AP2 but does not enable the link temporarily.

[0090] At step S202, the STA initiates the roaming decision.

[0091] At step S203, the STA sends the remaining media access control (MAC) protocol data units (MPDUs) that need to be sent to AP1 through uplink (UL) transmission completion.

[0092] At step S204, the STA sends a roaming announcement information (RAI) frame to AP1, indicating that the roaming preparation operation is started.

[0093] At step S205, the context of the STA is transferred from AP1 to AP2.

[0094] At step S206, the data path switching is performed between AP1 and AP2.

[0095] At step S207, the AP2 receives controller sends downlink (DL) data to the STA.

[0096] At step S208, the STA receives a roaming announcement response (RAR) frame sent by AP1. The RAR frame indicates that the link between the STA and AP2 is enabled.

[0097] At step S209, the STA, AP2, and controller perform UL / DL data transmission.

[0098] At step S210, AP1 sends the remaining data packets of the STA to the STA.

[0099] At steps S211-S212, after the last SN is cleared or timed out on AP1, AP1 closes the link between the STA and AP1.

[0100] At step S213, the STA, AP2, and controller perform UL / DL data transmission.

[0101] During the roaming process, if the STA (or Non-AP MLD) can only communicate with one AP MLD at the same time, the signaling flow can be as shown in FIG. 3.

[0102] At step S301, the STA requests to add a link with AP2 but does not enable the link temporarily.

[0103] At step S302, the STA initiates a roaming decision.

[0104] At step S303, the STA sends a remaining MPDU to AP1.

[0105] At step S304, the STA sends a RAI frame to AP1, indicating to start a roaming preparation operation.

[0106] At step S305, the context of the STA is transferred from AP1 to AP2.

[0107] At step S306, a data path switch is performed between AP1 and AP2.

[0108] At step S307, AP2 receives DL data sent by the controller to the STA.

[0109] At step S308, AP1 sends a remaining data packet to the STA.

[0110] At step S309, the STA receives a RAR frame sent by AP1. The RAR frame indicates to close the link between the STA and AP1 and to enable the link between the STA and AP2.

[0111] At step S310, UL / DL data transmission is performed between the STA, AP2 and the controller.

[0112] In the roaming process, if the STA (or Non-AP MLD) can only communicate with one AP MLD at the same time, and the STA switches to the target AP immediately after sending the RAI frame without context transfer, the signaling flow of seamless roaming based on non-co-located AP MLDs can be as shown in FIG. 4.

[0113] At step S401, the STA requests to add a link with AP2 but does not enable the link temporarily.

[0114] At step S402, the STA initiates a roaming decision.

[0115] At step S403, the STA sends a remaining MPDU to AP1.

[0116] At step S404, the STA sends a RAI frame to AP1, indicating to start a roaming preparation operation.

[0117] At step S405, a data path switch is performed between AP1 and AP2.

[0118] At step S406, the AP2 receives the DL data sent by the controller to the STA.

[0119] At step S407, the STA receives the RAR frame sent by the AP1. The RAR frame indicates to close the link between the STA and the AP1 and to enable the link between the STA and the AP2.

[0120] At step S408, UL / DL data transmission is performed between the STA, the AP2 and the controller.

[0121] Seamless roaming procedure based on over-the-distribution system (over-the-DS) hot-standby association

[0122] DS is a system for interconnecting a group of basic service sets (BSSs) and local area networks (LANs) to create an extended service set (ESS). Hot-standby association is a technical means to improve the reliability and speed of WIFI roaming, which ensures that the client device can quickly switch to the standby AP when the current connected AP has a problem, so as to realize seamless roaming through pre-authentication and standby connection state.

[0123] The related art (see proposal 23 / 1897r0 for example) proposes a seamless roaming signaling procedure based on over-the-DS hot-standby association. The signaling procedure can be as shown in FIG. 5.

[0124] At step S501, the current AP MLD sends a beacon request to the Non-AP MLD.

[0125] At step S502, the Non-AP MLD sends a probe request to the target AP MLD.

[0126] At step S503, the target AP MLD sends a probe response to the Non-AP MLD.

[0127] At step S504, the Non-AP MLD sends a beacon report to the current AP MLD.

[0128] At step S505, the current AP MLD sends a BSS transition management (BTM) request to the Non-AP MLD.

[0129] At step S506, the Non-AP MLD sends a BTM response to the current AP MLD.

[0130] At step S507, the current AP MLD forwards a fast basic service set transition (FT) request sent by the Non-AP MLD to the target AP MLD.

[0131] At step S508, the current AP MLD forwards an FT response sent by the target AP MLD to the Non-AP MLD.

[0132] At step S509, the Non-AP MLD sends a reassociation request to the target AP MLD.

[0133] At step S510, the target AP MLD sends a reassociation response to the Non-AP MLD.

[0134] At step S511, the Non-AP MLD sends a dynamic host configuration protocol (DHCP) discover message to the target AP MLD.

[0135] At step S512, the target AP MLD sends a DHCP offer message to the Non-AP MLD.

[0136] At step S513, the Non-AP MLD sends a DHCP request message to the target AP MLD.

[0137] At step S514, the target AP MLD sends a DHCP acknowledge (ACK) message to the Non-AP MLD.

[0138] It should be noted that in a system architecture based on Over-the-DS hot backup association, the current AP MLD and the neighboring AP MLD can be connected through a DS, as shown in FIG. 6.

[0139] Cooperative roaming procedure through target AP MLD

[0140] The related art (such as Proposal 24 / 398r0) proposes a cooperative roaming procedure through the target AP MLD, the flowchart of which can be as shown in FIG. 7.

[0141] Referring to FIG. 7, at step S701, the STA sends a link reconfiguration notify to the serving AP MLD. The link reconfiguration notify can include one or more of the following: related information of multiple requested target AP MLDs, a session management data element (SMDE).

[0142] At step S702, near static contexts (such as protocols, capabilities, etc.) are transferred to multiple candidate target AP MLDs.

[0143] At step S703, the target AP MLD obtains the key of the Non-AP MLD (if the key has not been installed). The key can include a pairwise master key (PMK), a pairwise transient key (PTK).

[0144] At step S704, the serving AP MLD sends a link reconfiguration notify to the STA. The link reconfiguration notify can include one or more of the following: related information of multiple candidate target AP MLDs and the SMDE.

[0145] At step S705, the received signal strength indication (RSSI) of the STA decreases, and it is decided to roam to the target AP MLD.

[0146] At step S706, the STA sends a link reconfiguration request to the target AP MLD. The link reconfiguration request is sent in the form of a protected management frame (PMF).

[0147] At step S707a, the target AP MLD requests context transfer from the serving AP MLD. Since the near static contexts have been transferred previously, this time, the dynamic contexts (such as SN, PN, block acknowledgment (BA), etc.) are mainly transferred.

[0148] At step S707b, the target AP MLD starts DS mapping update.

[0149] At step S707c, the target AP MLD requests data transmission from the serving AP MLD (this step is optional).

[0150] At step S708, the target AP MLD sends a link reconfiguration response to the STA. The link reconfiguration response can include one or more of the following: status, group key, association identifier (AID), SMDE.

[0151] At step S709, UL / DL data transmission is performed between the STA and the target AP MLD.

[0152] Single / seamless mobility domain (SMD) roaming based on non-collocated AP MLDs

[0153] A SMD-based roaming signaling procedure is proposed in related art (e.g., 24 / 0655r0), in which one SMD can include one serving AP MLD and multiple target AP MLDs. The roaming signaling procedure is shown in FIG. 8.

[0154] At step S801, the STA initiates association with the SMD by interacting with the serving AP MLD for (re)association request / response.

[0155] At step S802, 802.1X extensible authentication protocol (EAP) authentication is performed between the STA and the serving AP MLD. The authentication procedure can skip the pre-shared key (PSK) acquisition procedure and the simultaneous authentication of equals (SAE) procedure.

[0156] At step S803, the STA and the serving AP MLD generate a PMK.

[0157] At step S804, four-way handshake is performed between the STA and the serving AP MLD.

[0158] At step S805, the STA and the serving AP MLD generate a PTK.

[0159] At step S806, the STA sends a roaming preparation request to the serving AP MLD to request link establishment with multiple candidate target AP MLDs.

[0160] At step S807, the roaming context transfer is performed between the serving AP MLD and the candidate target AP MLD. The context to be transferred here can include a link, a quasi-static context, a capability, etc.

[0161] At step S808, the candidate target AP MLD installs a PMK and a PTK.

[0162] At step S809, the serving AP MLD sends a roaming preparation response to the STA.

[0163] At step S810, the STA transmits UL data between the STA and the serving AP MLD.

[0164] At step S811, the STA sends a roaming request to the serving AP MLD. The roaming request can be PMF-protected.

[0165] At step S812, the roaming context transfer is performed between the serving AP MLD and the target AP MLD. The context to be transferred here can include an SN, a PN, a BA, etc.

[0166] At step S813, the target AP MLD enables DS mapping.

[0167] At step S814, the target AP MLD opens an 802.1X port.

[0168] At step S815, the serving AP MLD sends a roaming response to the STA. The roaming response can be PMF-protected.

[0169] At step S816, UL / DL data transmission is performed between the STA and the target AP MLD.

[0170] At step S817, the serving AP MLD sends the buffered DL data to the STA.

[0171] At step S818, the serving AP MLD notifies the target AP MLD that the DL data buffered by the serving AP MLD has been delivered or timed out.

[0172] At steps S819-S820, the STA and the target AP MLD re-generate a PTK.

[0173] The related art mentioned above that when the roaming preparation procedure is close to the actual roaming execution procedure, resource reservation for a limited time on multiple candidate target AP MLDs can be considered, and the roaming execution procedure should be triggered within the limited time.

[0174] The seamless roaming procedure proposed by the related art is described in detail above. As can be seen from the description above, in the process of roaming from the source AP to the target AP by the STA, if the STA sends the roaming request frame, the roaming response frame needs to be received first, and then the communication with the target AP can be started. However, when the wireless channel deteriorates and / or the channel time resource is insufficient (such as lack of transmission opportunity (TXOP)), the transmission of the roaming response frame can have a large delay, thereby causing a large delay of the seamless roaming procedure.

[0175] To solve the above problem, the embodiment of the present application introduces first time information. The first time information can assist the first STA to decide the timing of starting the communication with the target AP, thereby reducing the latency of the seamless roaming procedure, and further improving the reliability of the seamless roaming procedure.

[0176] The method provided by the embodiment of the present application will be described in detail below in combination with FIG. 9.

[0177] FIG. 9 is a schematic flowchart of a wireless communication method provided by the embodiment of the present application. The method of FIG. 9 is described from the perspective of the interaction between the first STA and the first AP. The first STA in FIG. 9 can be a STA that is preparing to roam from a source AP to a target AP. The first STA can be a Non-AP STA or a Non-AP MLD. The first AP in FIG. 9 can be any one of the APs participating in the roaming procedure of the first STA. For example, the first AP can be the source AP (or the current AP or the serving AP). Alternatively, the first AP can also be the target AP. In addition, it needs to be noted that the first AP mentioned in the embodiment of the present application can be an AP STA or an AP MLD.

[0178] In step S901, the first STA receives a first frame sent by the first AP. The first frame can be any type of frame received before the first STA requests to roam from the source AP to the target AP. For example, the first frame can include one or more of the following: a roaming preparation response frame, a link reconfiguration notification frame, a link reconfiguration response frame, or a probe response frame.

[0179] The first frame can include first time information. The first time information can be used by the first STA in the roaming procedure.

[0180] As can be seen from the above description, the embodiment of the present application introduces first time information for the roaming procedure of the first STA. The first time information can assist the first STA to decide the timing of starting the communication with the target AP, thereby improving the reliability of the seamless roaming procedure.

[0181] The first time information can be used to determine the first time in the roaming process of the first STA. The first time information can be a parameter indicating a time duration, which can directly indicate a time duration or can indicate a timer. The first time mentioned herein can be a time (or opportunity) at which the first STA is allowed to start communicating with the target AP; or the first time can be a time (or opportunity) at which the first STA is allowed to start communicating with the target AP in a case that the first STA does not receive a roaming response frame (the roaming request frame can be a second frame mentioned below, and the roaming response frame can be a response frame of the second frame, and the second frame will be described in detail below). That is, the first time information can be used to assist the first STA to decide an opportunity to start communicating with the target AP.

[0182] It should be understood that the above-mentioned "allowing the first STA to start communicating with the target AP" can mean that the first STA can start communicating with the target AP at the first time in a case that the first STA does not receive the roaming response frame, and whether the first STA starts communicating with the target AP at the first time can be autonomously decided by the first STA. Alternatively, the above-mentioned "allowing the first STA to start communicating with the target AP" can also mean that the first time is the time at which the first STA starts communicating with the target AP in a case that the first STA does not receive the roaming response frame.

[0183] It should also be understood that if the first STA has received the roaming response frame before the first time, the first STA can start communicating with the target AP when the first time arrives, or can start communicating with the target AP before the first time arrives (that is, in this case, the first STA can choose to ignore the first time information).

[0184] In some embodiments, the above-mentioned "the first time information is used to determine the first time in the roaming process of the first STA" can include or be replaced by: the first time information is used to indicate a time duration required for the target AP to perform a roaming preparation operation in the roaming process. After the first AP provides the first STA with the time duration required for the target AP to perform the roaming preparation operation, the first STA can determine (or estimate) a completion time of the roaming preparation operation of the target AP. After the first STA determines that the target AP has completed the roaming preparation operation, if the first STA still does not receive the roaming response frame, the first STA can determine that a case of wireless channel deterioration or insufficient channel time resource can occur. In this case, the first STA can selectively start communicating with the target AP.

[0185] The time length required for the target AP to perform the roaming preparation operation mentioned above can include one or more of the following: a minimum time length, an average time length, or a maximum time length required for the target AP to perform the roaming preparation operation. As an example, the first time information carried in the first frame can indicate to the first STA a maximum time length required for the target AP to perform the roaming preparation operation, and if the time length for the target AP to perform the roaming preparation operation exceeds the maximum time length, it means that the roaming preparation procedure of the target AP times out, and therefore, in this example, the first time information can also be referred to as roaming preparation timeout time information. Based on the maximum time length required for the target AP to perform the roaming preparation operation, the first STA can more accurately determine the completion time of the roaming preparation operation of the target AP, and thus more accurately determine the time to start communicating with the target AP.

[0186] In some implementations, the aforementioned "the first time information is used to determine the first time in the roaming procedure of the first STA" can include or be replaced by: the first time information is used to indicate a time interval with the second time as a starting time. The second time mentioned here can be a certain time earlier than the first time. The end time of the time interval mentioned here can be the time when the first STA is allowed to start communicating with the target AP. That is, the first STA starts counting from the second time, and if the roaming response frame is not received after the aforementioned time interval, the first STA can start communicating with the target AP.

[0187] The application embodiments do not make specific limitations on the definition of the second time. In some implementations, the second time can be determined based on the transmission time of the second frame. The second frame mentioned here can be, for example, a frame used to request roaming from the source AP to the target AP, or a frame used to trigger the target AP to perform the roaming preparation operation. As an example, the second time can be the time when the second frame is sent (such as the transmission start time or end time of the second frame). That is, after the first STA sends the second frame, if a response frame (which can be a roaming response frame) of the second frame is not received within the time interval indicated by the first time information, the first STA is allowed to start communicating with the target AP at the first time. As another example, the second time can be the time when the second frame is successfully sent (such as the transmission end time of the acknowledgement frame (ACK frame) of the second frame). That is, after the first STA confirms that the second frame is successfully transmitted, if a response frame (which can be a roaming response frame) of the second frame is not received within the time interval indicated by the first time information, the first STA is allowed to start communicating with the target AP at the first time.

[0188] According to the above description, in the roaming process, even if the first STA cannot receive the roaming request response frame due to the deterioration of the wireless channel or the lack of channel time resources, the first STA can communicate with the target AP at the first time or at the end time of the time interval starting from the second time based on the indication of the first time information, thereby reducing the delay of the seamless roaming process and improving the reliability of the seamless roaming process.

[0189] The above describes the definition of the first time information. The following describes the communication rule of the first STA based on the first time information.

[0190] In some embodiments, if the first STA does not receive the roaming response frame (which can be the response frame of the second frame mentioned above) within the time length or time interval indicated by the first time information, the first STA is allowed to start communicating with the target AP (or the first STA can selectively start communicating with the target AP). Of course, if the first STA receives the roaming response frame (which can be the response frame of the second frame mentioned above) within the time length or time interval indicated by the first time information, the first STA can also start communicating with the target AP in advance. The above-mentioned starting of the first STA to communicate with the target AP can include that the first STA starts to establish a connection with the target AP and / or the first STA starts to perform UL / DL data transmission with the target AP.

[0191] In other embodiments, if the first STA does not receive the response frame of the second frame mentioned above within the time length or time interval indicated by the first time information, the first STA is allowed to send a third frame to the target AP (or the first STA can selectively send the third frame to the target AP). The third frame mentioned here can be used to inquire whether the roaming operation is completed. Accordingly, the third frame can be referred to as a roaming query frame. Alternatively, the third frame can be used to request information in the response frame of the second frame. Alternatively, the third frame can be used to request various possible contexts required for data transmission with the target AP. For example, the third frame can be used to request one or more of the following: a key, a BA, and a protocol.

[0192] As an example, after the first STA sends the RAI frame (corresponding to the second frame mentioned above) to the source AP, if the first STA does not receive the RAR frame (corresponding to the response frame of the second frame mentioned above) sent by the source AP within the time length or time interval indicated by the first time information, the first STA can send a roaming query frame to the target AP to inquire whether the roaming operation is completed, and request the key, the BA, and the protocol in the RAR frame through the roaming query frame.

[0193] The target AP, after receiving the third frame sent by the first STA, can send a response frame of the third frame to the first STA. As mentioned above, the third frame can be referred to as a roaming query frame, and accordingly, the response frame of the third frame can be a roaming query response frame. The response frame of the third frame can be used to indicate whether the roaming preparation operation described above has been completed; and / or, the response frame of the third frame can be used to provide information in the response frame of the second frame; and / or, the response frame of the third frame can be used to provide various possible contexts (such as keys, BAs, and protocols) required for data transmission with the target AP.

[0194] As mentioned above, the first frame can include a roaming preparation response frame, a link reconfiguration notification frame, a link reconfiguration response frame, or a probe response frame. The bearing manner of the first time information in the first frame is different when the frame type of the first frame is different. The bearing manner of the first time information in the first frame will be described in detail below in combination with specific embodiments.

[0195] Implementation manner one: bearing the first time information in the roaming preparation response frame

[0196] In the implementation manner one, the first frame is a roaming preparation response frame. For example, a new action frame can be defined as the roaming preparation response frame. The roaming preparation response frame can include a frame body field, and the first time information mentioned above can be borne in the frame body field of the roaming preparation response frame.

[0197] FIG. 10A is an example diagram of the format of the roaming preparation response frame. Referring to FIG. 10A, the roaming preparation response frame includes one or more of the following fields: frame control, duration, address 1, address 2, address 3, sequence control, high throughput (HT) control, frame body, and frame check sequence (FCS). The frame control field can be used to indicate basic information such as frame type. The duration field can be used to indicate the time interval from the end time of the current frame to the end time of the TXOP. The address 1 field can be used to indicate the receiving address. The address 2 field can be used to indicate the sending address. The address 3 field can be the same as the address 2 field. The sequence control field can be used to indicate the sequence number of the MAC service data unit (MSDU) and the MPDU. The HT control field can be used to carry various control signaling.

[0198] The frame body field of the roaming preparation response frame can include a roaming preparation timeout field. The roaming preparation timeout field can be used to indicate the first time information. For example, the roaming preparation timeout field can indicate a maximum time duration for the target AP to perform the roaming preparation operation, or indicate a time interval between the first STA successfully sending the roaming request frame and starting to attempt to communicate with the target AP.

[0199] As shown in FIG. 10B, the frame body field of the roaming preparation response frame can include one or more of the following fields: category, protected ultra high resolution (UHR) action, dialog token, STA address, target AP address, and roaming preparation timeout. The category field can be used to indicate the type of the action frame, and can take any integer value between 40 and 125. For example, the category field can take the value 40 to indicate a protected UHR type of action frame. The protected UHR action field can be used to indicate the subtype of the protected UHR action frame, and can take any integer value between 0 and 255. For example, the protected UHR action field can take the value 1 to indicate the roaming preparation response frame. The dialog token field can be set to a non-zero value to indicate a request / response session. The STA address field can be used to indicate the MAC address of the first STA (e.g., a Non-AP MLD or a Non-AP STA) that sent the roaming preparation request frame corresponding to the frame. The target AP address field can be used to indicate the BSSID of the BSS of a target AP.

[0200] Implementation Two: Carrying the first time information in a link reconfiguration notification frame

[0201] In implementation two, the first frame can be a link reconfiguration notification frame. For example, the link reconfiguration notification frame includes a reconfiguration multi-link element field, and the first time information mentioned above can be carried in the reconfiguration multi-link element field.

[0202] Further, in some implementations, the reconfiguration multi-link element field can include a link information field, and the first time information is carried in the link information field.

[0203] Further, in some implementations, the link information field includes a STA information field, and the STA information field includes a first field for carrying the first time information.

[0204] In addition, in some implementations, the link information field further includes a STA control field, and the STA control field includes a second field used to indicate whether the STA information field contains the first field. For example, when the second field takes a first value (such as 1), it can indicate that the STA information field contains the first field. For another example, when the second field takes a second value (such as 0), it can indicate that the STA information field does not contain the first field.

[0205] In the following, an example of the link reconfiguration notification frame provided by the embodiments of the present application is given with reference to FIG. 11A to FIG. 11J.

[0206] FIG. 11A is an example diagram of a format of a link reconfiguration announcement frame. Referring to FIG. 11A, the link reconfiguration announcement frame includes one or more of the following fields: frame control, duration, address 1, address 2, address 3, sequence control, high throughput (HT) control, frame body, and frame check sequence (FCS). The frame control field can be used to indicate basic information such as frame type. The duration field can be used to indicate a time interval from the end time of the current frame to the end time of the TXOP. The address 1 field can be used to indicate a receiving address. The address 2 field can be used to indicate a sending address. The address 3 field can be the same as the address 2 field. The sequence control field can be used to indicate the sequence number of MSDUs and MPDUs. The HT control field can carry various control signaling. As shown in FIG. 11B, the frame body field of the link reconfiguration announcement frame can include one or more of the following fields: category, protected enhanced high throughput (EHT) action, dialog token, and reconfigure multi-link element. The category field can be used to indicate the type of the action frame. For example, when the category field takes the value of 37, it can indicate a protected EHT type of action frame. The protected EHT action field can be used to indicate the subtype of the protected EHT action frame. For example, when the protected EHT action field takes the value of 10, it can indicate the link reconfiguration announcement frame. The dialog token field can be set to a non-0 value to indicate a notification sequence number. The reconfigure multi-link element field can be used to announce the multi-link reconfiguration operation of the AP MLD. In addition, the reconfigure multi-link element field can also be used to start the ML reconfiguration operation. For example, the reconfigure multi-link element field can be used to add a new link to the STA's link or delete a link from the STA's link, and provide the ML reconfiguration suggestion for the AP MLD to the STAs associated therewith.

[0207] FIG. 11C is an example diagram of the format of the reconfiguration multi-link element field. As shown in FIG. 11C, the reconfiguration multi-link element field can include one or more of the following fields: element (element) ID, length, element ID extension, multi-link control, common info, link info. The element ID field can have a value of 255. The element ID extension field can have a value of 107. The element ID field and the element ID extension field can jointly indicate that the element is a multi-link element. The length field can be used to indicate the length of the multi-link element. The format of the multi-link control field can be as shown in FIG. 11D. The multi-link control field can include one or more of the following subfields: type, reserved, and presence bitmap. The type subfield can be used to indicate different variant types of the multi-link element. For example, the type subfield can have a value of 2 to indicate the reconfiguration multi-link element. The presence bitmap subfield can be used to indicate whether various subfields in the common info field are present.

[0208] The common info field can carry information common to all links except the link ID info subfield and the BSS parameters change count subfield of the multi-link element. The common info field can include one or more of the following subfields: common info length, MLD MAC address, extended multi-link (EML) capabilities, MLD capabilities and operations, and extended MLD capabilities and operations. FIG. 11E is an example diagram of the format of the common info field. Referring to FIG. 11E, the common info length subfield can be used to indicate the number of bytes of the common info field. The MLD MAC address subfield can be used to indicate the MAC address of the MLD described by the reconfiguration multi-link element. The EML capabilities subfield can be used to indicate various capabilities of the extended multi-link selection request (EMLSR) operation and the extended multi-link measurement report (EMLMR) operation. The MLD capabilities and operations subfield can be used to indicate various capabilities of the MLD operation. The extended MLD capabilities and operations subfield can be used to indicate various capabilities of the extended MLD operation.

[0209] The link info field in FIG. 11C can include one or more Per-STA Profile subelement. The Per-STA Profile subelement can have a format as shown in FIG. 11F, for example. As shown in FIG. 11F, the Per-STA Profile subelement includes one or more of the following: a subelement ID, a length, a STA control, a STA info, a STA profile.

[0210] FIG. 11G is an example diagram of a format of the STA control field. As shown in FIG. 11G, the STA control field can include one or more of the following subfields: a link ID, a complete profile, a STA MAC address present, an AP removal present, a reconfiguration operation type, an operation parameters present, a neighbor statistics report (NSTR) bitmap size, an NSTR indication bitmap present, a roaming preparation timeout present, and a reserved.

[0211] The link ID subfield can be used to specify a value uniquely identifying a link operated by the reported AP in the reconfiguration multi-link element sent by an AP MLD, and can be used to specify a link indicating a reconfiguration operation in the reconfiguration multi-link element sent by a non-AP MLD.

[0212] When the complete profile subfield has a value of 1, it can indicate that the STA profile subfield is included in the Per-STA profile subelement. When the complete profile subfield has a value of 0, it can indicate that the STA profile subfield is not included in the Per-STA profile subelement.

[0213] When the STA MAC address present subfield has a value of 1, it can indicate that the STA MAC address subfield is present in the STA info field. When the STA MAC address present subfield has a value of 0, it can indicate that the STA MAC address subfield is not present in the STA info field.

[0214] The AP Remove Present subfield with a value of 1 can indicate that the AP Remove subfield is present in the STA Info field. The AP Remove Present subfield with a value of 0 can indicate that the AP Remove subfield is not present in the STA Info field.

[0215] The Reconfiguration Operation Type subfield is used to indicate the type of multi-link operation (MLO) update for the link indicated by the Link ID field. The encoding of the Reconfiguration Operation Type subfield and the corresponding MLO update types can be found in FIG. 11H. As shown in FIG. 11H, an encoding of 0 corresponds to an MLO update type of AP Remove, an encoding of 1 corresponds to an MLO update type of Operation Parameter Update, an encoding of 2 corresponds to an MLO update type of Add Link, an encoding of 3 corresponds to an MLO update type of Delete Link, an encoding of 4 corresponds to an MLO update type of NSTR Status Update, and encodings of 5 to 15 are reserved bits.

[0216] The Operation Parameters Present subfield with a value of 1 can indicate that the Operation Parameters subfield is present in the STA Info field. The Operation Parameters Present subfield with a value of 0 can indicate that the Operation Parameters subfield is not present in the STA Info field.

[0217] The NSTR Bitmap Size subfield can indicate the size of the NSTR Indication Bitmap subfield (if present) in the STA Info field. The NSTR Bitmap Size subfield can be set to 1 if the corresponding NSTR Indication Bitmap subfield is one octet in length. The NSTR Bitmap Size subfield can be set to 0 if the corresponding NSTR Indication Bitmap subfield is two octets in length. If the NSTR Indication Bitmap Present subfield is equal to 0, the NSTR Bitmap Size subfield in the STA Control field is reserved. The NSTR Indication Bitmap Present subfield with a value of 1 can indicate that the NSTR Indication Bitmap subfield is present in the STA Info field, and a value of 0 can indicate that the NSTR Indication Bitmap subfield is not present in the STA Info field.

[0218] The STA control field can comprise a roaming preparation timeout present field. The roaming preparation timeout present field can correspond to the second field mentioned above. The roaming preparation timeout present field is used to indicate whether the STA information field contains a roaming preparation timeout field, which corresponds to the first field mentioned above, for carrying the first time information. For example, when the roaming preparation timeout present field takes a value of 1, it indicates that the STA information field contains the roaming preparation timeout field; when the roaming preparation timeout present field takes a value of 0, it indicates that the STA information field does not contain the roaming preparation timeout field.

[0219] FIG. 11I is an example diagram of the format of the STA information field. As shown in FIG. 11I, the STA information field can comprise one or more of the following subfields: STA info length, STA MAC address, AP removal timer, operation parameters, NSTR indication bitmap, roaming preparation timeout.

[0220] The STA info length field can be used to indicate the length of the STA information field.

[0221] The STA MAC address carries the MAC address of the STA operating or capable of operating on the link identified by the link ID subfield and belongs to the same MLD as the STA transmitting the reassociation multi-link element.

[0222] The AP removal timer subfield can represent the number of target beacon transmission times (TBTTs) of the AP corresponding to each station profile subelement until the AP is removed. A value of 1 for the AP removal timer subfield indicates that the AP removal occurs at the next TBTT. A value of 0 for the AP removal timer subfield is reserved.

[0223] The NSTR indication bitmap subfield can be used to indicate the NSTR link pairs of the Non-AP MLD. The roaming preparation timeout subfield can be used to indicate the timeout duration or maximum duration for the AP MLD or the AP to perform the roaming preparation operation on the link indicated by the link ID field, or to indicate the time interval between the successful transmission of the roaming request frame by the Non-AP MLD and the start of attempting to communicate with the target AP MLD or target AP.

[0224] The roaming preparation timeout field can be used to indicate the first time information mentioned above. For example, the roaming preparation timeout field can indicate a maximum time duration for the AP / AP MLD on the link indicated by the link ID field to perform the roaming preparation operation, or a time interval between the Non-AP MLD successfully sending the roaming request frame and starting to attempt to communicate with the target AP MLD / AP.

[0225] FIG. 11J is an example diagram of the format of the operation parameter subfield. As shown in FIG. 11J, the operation parameter subfield can include a presence indication subfield and an operation parameter information subfield. The presence indication subfield can include a maximum MPDU length present subfield, a maximum aggregated-multiple short data units (Maximum A-MSDU) length present subfield, and a reserved subfield. The operation parameter information subfield can include a maximum MPDU length subfield, a maximum A-MSDU length subfield, and a pad subfield. The maximum MPDU length present subfield with a value of 1 indicates that the maximum MPDU length subfield is present in the operation parameter information subfield, and the maximum MPDU length present subfield with a value of 0 indicates that the maximum MPDU length subfield is not present in the operation parameter information subfield. The maximum A-MSDU length present subfield with a value of 1 indicates that the maximum A-MSDU length subfield is present in the operation parameter information subfield. The maximum A-MSDU length present subfield with a value of 0 indicates that the maximum A-MSDU length subfield is not present in the operation parameter information subfield. The maximum MPDU length subfield can be used to indicate the length of the maximum MPDU. The maximum A-MSDU length subfield can be used to indicate the length of the maximum A-MSDU.

[0226] Implementation Three: Carrying the first time information in the link reconfiguration response frame

[0227] In implementation three, the first frame can be a link reconfiguration response frame. For example, the link reconfiguration response frame includes a basic multi-link element field, and the first time information mentioned above can be carried in the basic multi-link element field.

[0228] Further, in some implementations, the basic multi-link element field can include a link information field, and the first time information is carried in the link information field.

[0229] Further, in some implementations, the link information field includes a STA information field, and the STA information field includes a third field, and the third field is used to carry the first time information.

[0230] In addition, in some implementations, the link information field further includes a STA control field, and the STA control field includes a fourth field, and the fourth field is used to indicate whether the STA information field contains the third field. For example, when the fourth field takes a third value (such as 1), it can indicate that the STA information field contains the third field. For another example, when the fourth field takes a fourth value (such as 0), it can indicate that the STA information field does not contain the third field.

[0231] The following takes FIGS. 12A to 12I as an example to give an entity of the link reconfiguration response frame provided by the embodiments of the present application.

[0232] FIG. 12A is an example diagram of the format of the link reconfiguration response frame. Referring to FIG. 12A, the link reconfiguration response frame includes one or more of the following fields: frame control, duration, address 1, address 2, address 3, sequence control, high throughput (HT) control, frame body, and frame check sequence (FCS). The frame control field can be used to indicate basic information such as frame type. The duration field can be used to indicate the time interval from the end time of the current frame to the end time of the TXOP. The address 1 field can be used to indicate the receiving address. The address 2 field can be used to indicate the sending address. The address 3 field can be the same as the address 2 field. The sequence control field can be used to indicate the sequence number of MSDU and MPDU. The HT control field can carry various control signaling.

[0233] As shown in FIG. 12B, the frame body field of the link reconfiguration response frame can include one or more of the following subfields: category, protected enhanced high throughput (EHT) action, dialog token, count, reconfiguration status list, group key data, overlapping channel information (OCI) element, and basic multi-link element.

[0234] The category subfield can be used to indicate the type of the action frame. For example, when the category subfield takes the value of 37, it can indicate a protected EHT type of action frame.

[0235] The protected EHT action subfield can be used to indicate the sub-type of the protected EHT action frame. For example, when the protected EHT action subfield takes the value of 10, it can indicate a link reconfiguration notification frame.

[0236] The dialog token subfield can be set to a non-0 value to indicate one request / response session.

[0237] The count subfield can be set to the number of reconfiguration status duples in the reconfiguration status list subfield.

[0238] The reconfiguration status list subfield can contain one or more reconfiguration status duples. FIG. 12C is an example diagram of the format of the reconfiguration status duple. As shown in FIG. 12C, the reconfiguration status duple can include a link ID info subfield and a status subfield. The link ID info subfield can indicate the link identifier of the AP that is added or deleted in the existing multi-link setup in the corresponding link reconfiguration request frame. The status subfield can indicate the status of the link reconfiguration operation of the link corresponding to the link ID subfield.

[0239] The group key data subfield is optionally present and contains the group key for the links that have been successfully added to the multi-link setup (status value set to success). If the group key data subfield is present, the OCI element subfield is optionally present. The OCI element subfield can contain one OCI element. If the AP MLD accepted at least one link addition, a basic multi-link element subfield is included to provide profile information for each STA for one or more APs corresponding to the links successfully added to the multi-link setup of the Non-AP MLD. If the AP MLD did not accept the link addition, the basic multi-link element subfield is not included. The basic multi-link element subfield can carry information related to the MLD and its affiliated STAs that was broadcasted during the multi-link discovery and multi-link setup. FIG. 12D is an example diagram of the format of the basic multi-link element field. As shown in FIG. 12D, the basic multi-link element field can include one or more of the following fields: element ID, length, element ID extension, multi-link control, common info, link info. The element ID field can have a value of 255. The length field can be used to indicate the length of the multi-link element.

[0240] The format of the multi-link control field can be as shown in FIG. 12E. The multi-link control field can include one or more of the following subfields: type, reserved, and presence bitmap. The type subfield can be used to indicate different variant types of the multi-link element. For example, the type subfield can have a value of 0 to indicate a basic multi-link element. The presence bitmap subfield can be used to indicate whether various subfields in the common info field are present.

[0241] The common info field can carry information common to all links except the link ID info subfield and the BSS parameters change count subfield of the multi-link element. The common info field can include one or more of the following subfields: common info length, MLD MAC address, extended multi-link (EML) capabilities, MLD capabilities and operations, and extended MLD capabilities and operations. FIG. 12F is an example diagram of the format of the common info field. Referring to FIG. 12F, the common info length subfield can be used to indicate the number of bytes of the common info field. The MLD MAC address subfield can be used to indicate the MAC address of the MLD described by the reconfiguration multi-link element. The EML capabilities subfield can be used to indicate various capabilities of the extended multi-link selection request (EMLSR) operation and the extended multi-link measurement report (EMLMR) operation. The MLD capabilities and operations subfield can be used to indicate various capabilities of the MLD operation. The extended MLD capabilities and operations subfield can be used to indicate various capabilities of the extended MLD operation.

[0242] The link info field in FIG. 12D can include one or more Per-STA Profile subelements. The Per-STA Profile subelement, for example, can have a format as shown in FIG. 12G. As shown in FIG. 12G, the Per-STA Profile subelement includes one or more of the following: subelement ID, length, STA control, STA info, STA profile.

[0243] FIG. 12H is an example diagram of the format of the STA control field. As shown in FIG. 12H, the STA control field can include one or more of the following subfields: link ID, complete profile, STA MAC address present, beacon interval present, timing synchronization function (TSF) offset present, delivery traffic indication map (DTIM) info present, NSTR link pair present, NSTR bitmap size, BSS parameters change count present, and reserved.

[0244] The link ID subfield can specify a value that uniquely identifies the link on which the reporting STA is operating.

[0245] When the complete profile subfield has a value of 1, it can indicate that the STA profile subfield is included in the Per-STA profile subelement. When the complete profile subfield has a value of 0, it can indicate that the STA profile subfield is not included in the Per-STA profile subelement.

[0246] When the STA MAC address present subfield has a value of 1, it can indicate that the STA MAC address subfield is present in the STA information field. When the STA MAC address present subfield has a value of 0, it can indicate that the STA MAC address subfield is not present in the STA information field.

[0247] When the beacon interval present subfield has a value of 1, it can indicate that the beacon interval subfield is present in the STA information field. When the beacon interval present subfield has a value of 0, it can indicate that the beacon interval subfield is not present in the STA information field.

[0248] When the TSF offset present subfield has a value of 1, it can indicate that the TSF offset subfield is present in the STA information field. When the TSF offset present subfield has a value of 0, it can indicate that the TSF offset subfield is not present in the STA information field.

[0249] The DTIM info present subfield value of 1 can indicate that the DTIM info subfield is present in the STA info field, and a value of 0 can indicate that the DTIM info subfield is not present in the STA info field.

[0250] The NSTR link pair present subfield value of 1 can indicate that the NSTR link pair subfield is present in the STA info field, and a value of 0 can indicate that the NSTR link pair subfield is not present in the STA info field.

[0251] The NSTR bitmap size subfield can indicate the size of the NSTR indication bitmap subfield (if present) in the STA info field. The NSTR bitmap size subfield is set to 1 if the corresponding NSTR indication bitmap subfield is two octets in length, and the NSTR bitmap size subfield is set to 0 if the corresponding NSTR indication bitmap subfield is one octet in length. The NSTR bitmap size subfield in the STA control field is reserved if the NSTR indication bitmap present subfield is equal to 0.

[0252] The BSS parameters change count present subfield value of 1 can indicate that the BSS parameters change count subfield is present in the STA info field, and a value of 0 can indicate that the BSS parameters change count subfield is not present in the STA info field.

[0253] The STA control field can comprise a roaming preparation timeout present field. The roaming preparation timeout present field can correspond to the fourth field mentioned above. The roaming preparation timeout present field is used to indicate whether the STA information field contains a roaming preparation timeout field, which corresponds to the third field mentioned above, for carrying the first time information. For example, when the roaming preparation timeout present field has a value of 1, it indicates that the STA information field contains the roaming preparation timeout field; when the roaming preparation timeout present field has a value of 0, it indicates that the STA information field does not contain the roaming preparation timeout field. FIG. 121 is an example diagram of the format of the STA information field. As shown in FIG. 121, the STA information field can comprise one or more of the following subfields: STA info length, STA MAC address, beacon interval, TSF offset, DTIM info, NSTR indication bitmap, BSS parameters count, roaming preparation timeout.

[0254] The STA info length subfield can indicate the number of octets in the STA information field, including one octet for the STA info length subfield.

[0255] The STA MAC address subfield can carry the MAC address of the STA running on the link identified by the link ID subfield, and belongs to the same MLD as the STA of the basic multi-link element.

[0256] The beacon interval subfield can carry the beacon interval of the reported AP.

[0257] The TSF offset subfield can represent the offset between the TSF timer (TA) of the reported AP and the TSF timer of the reporting AP.

[0258] The DTIM info subfield can carry the DTIM count and DTIM period information of the reported AP.

[0259] The NSTR indication bitmap subfield can indicate the NSTR link pairs of the reported STA.

[0260] The BSS parameters count change count subfield can carry the latest BSS parameters change count corresponding to the reported AP.

[0261] The roaming preparation timeout subfield can be used to indicate the first time information mentioned above. For example, the roaming preparation timeout subfield can indicate a timeout duration or maximum duration for the AP MLD / AP to perform the roaming preparation operation on the link indicated by the link ID field, or indicate a time interval between the Non-AP MLD successfully sending the roaming request frame and starting to attempt to communicate with the target AP MLD / AP.

[0262] Implementation four: Carrying the first time information in the probe response frame

[0263] In implementation four, the first frame is a probe response frame. The probe response frame can include a frame body field, and the first time information mentioned above is carried in the frame body field of the probe response frame.

[0264] FIG. 13A is an example diagram of a format of a probe response frame. As shown in FIG. 13A, the probe response frame can include one or more of the following: frame control, duration, address 1, address 2, address 3, sequence control, high throughput (HT) control, frame body, and frame check sequence (FCS). The frame control field can be used to indicate basic information such as frame type. The duration field can be used to indicate a time interval from the end time of the current frame to the TXOP end time. The address 1 field can be used to indicate the receiving address. The address 2 field can be used to indicate the sending address. The address 3 field can be the same as the address 2 field. The sequence control field can be used to indicate the sequence number of MSDU and MPDU. The HT control field can be used to carry various control signaling.

[0265] FIG. 13B is an example diagram of a format of the frame body field of the probe response frame. As shown in FIG. 13B, the frame body field of the probe response frame can include one or more of the following fields: roaming preparation timeout field and link ID field. The link ID field can be used to indicate an identifier of a link. The roaming preparation timeout field can be used to indicate the first time information. For example, the roaming preparation timeout field can indicate a timeout duration or maximum duration for the AP MLD / AP to perform the roaming preparation operation on the link indicated by the link ID field, or indicate a time interval between the Non-AP MLD successfully sending the roaming request frame and starting to attempt to communicate with the target AP MLD / AP.

[0266] Through the information types defined in the first to fourth implementation manners and the corresponding use rules, the first STA can obtain a valid first time information through a corresponding frame when preparing to roam, and the first time information can reliably indicate when the first STA can start communication with the target AP. In this way, the roaming process delay caused by poor channel quality or insufficient channel time resources can be avoided.

[0267] It is mentioned above that the second frame can be a frame requesting roaming from the source AP to the target AP, or a frame triggering the target AP to perform a roaming preparation operation. It should be noted that the second frame can be any type of frame that can achieve the above functions, and the name of the second frame is not limited in the embodiments of the present application. In different roaming processes, the second frame can have different names. For example, the second frame can include one or more of the following frames: RAI frame, FT request frame, link reconfiguration request frame, and roaming request frame. In addition, the second frame can be a frame sent by the first STA to the source AP, or a frame sent by the first STA to the target AP.

[0268] Similarly, the type of the response frame of the second frame is not limited in the embodiments of the present application. For example, when the second frame is a RAI frame, the response frame of the second frame can be a RAR frame. When the second frame is an FT request frame, the response frame of the second frame can be an FT response frame. When the second frame is a link reconfiguration request frame, the response frame of the second frame can be a link reconfiguration response frame. When the second frame is a roaming request frame, the response frame of the second frame can be a roaming response frame.

[0269] It is mentioned above that in the roaming process, the target AP can perform a roaming preparation operation. The specific content of the roaming preparation operation is not limited in the embodiments of the present application. For example, the roaming preparation operation here can include one or more of the following: context transfer operation of the first STA; data transfer operation of the first STA.

[0270] The embodiments of the present application will be described in more detail below with reference to specific examples. It should be noted that the examples of FIGS. 14-19 are only intended to help those skilled in the art understand the embodiments of the present application, and are not intended to limit the embodiments of the present application to the specific values or specific scenarios illustrated. Those skilled in the art can obviously make various equivalent modifications or changes based on the examples of FIGS. 14-19, and such modifications or changes also fall within the scope of the embodiments of the present application.

[0271] Embodiment One

[0272] Embodiment one is a seamless roaming signaling process based on non-co-located AP MLD.

[0273] In the roaming process, if the Non-AP STA (or Non-AP MLD) can communicate with multiple non-collocated APs simultaneously, the signaling procedure of seamless roaming based on non-collocated AP MLD can be shown in FIG. 14.

[0274] Referring to FIG. 14, at step S1401, the Non-AP STA sends a link reconfiguration request frame to AP1, requesting to add a link with AP2 but not to enable the link temporarily.

[0275] At step S1402, AP1 returns a link reconfiguration response frame to the Non-AP STA, carrying a roaming preparation timeout time t, indicating that the timeout or maximum duration of the roaming preparation operation (such as context transfer operation, data transfer operation) performed by AP2 is t.

[0276] At step S1403, the Non-AP STA initiates a roaming decision.

[0277] At step S1404, the Non-AP STA sends the remaining MPDU to be sent to AP1 through UL.

[0278] At step S1405, the Non-AP STA sends an RAI frame to AP1, indicating that the roaming preparation operation is started. In addition, the roaming preparation timeout timer is started at the end of the Non-AP STA sending the RAI frame or the end of AP1 receiving the ACK frame of the RAI frame, with a duration of t.

[0279] At step S1406, the context of the Non-AP STA is transferred from AP1 to AP2.

[0280] At step S1407, a data path switching operation is performed between AP1 and AP2.

[0281] At step S1408, the DL data sent by the Non-AP STA is received by the AP2 controller.

[0282] At step S1409, due to the long time failure of AP1 to obtain TXOP, the RAR frame sent by AP1 cannot be successfully received by the Non-AP STA, or due to the dramatic change of the wireless channel quality between the Non-AP STA and AP1, the RAR frame sent by AP1 cannot be successfully received by the Non-AP STA. When the t duration of the roaming preparation timeout timer expires, the Non-AP STA can no longer wait for the RAR frame, but actively establish communication with AP2.

[0283] At step S1410, the Non-AP STA sends a roaming inquiry frame to AP2 to inquire whether the roaming preparation operation has been completed (this step is optional).

[0284] At step S1411, the Non-AP STA receives the roaming query response frame sent by the AP2 to obtain the query result and various possible context contents (e.g., key, BA, protocol) and the like (this step is optional).

[0285] At step S1412, UL / DL data transmission is performed between the Non-AP STA, the AP2 and the controller, and the link between the Non-AP STA and the AP1 is not closed for the time being.

[0286] At step S1413, the AP1 sends the remaining data packets of the Non-AP STA to the Non-AP STA.

[0287] At steps S1414-S1415, after the last SN is cleared or timed out on the AP1, the AP1 closes the link between the Non-AP STA and the AP1.

[0288] At step S1416, UL / DL data transmission is performed between the Non-AP STA, the AP2 and the controller.

[0289] Embodiment Two

[0290] Embodiment Two is a seamless roaming signaling procedure based on non-co-located AP MLD.

[0291] In the roaming process, if the Non-AP STA (or Non-AP MLD) can only communicate with one AP MLD at the same time, the signaling procedure can be as shown in FIG. 15. At step S1501, the Non-AP STA sends a link reconfiguration request frame to the AP1 to request to add a link with the AP2 but not to enable the link temporarily.

[0292] At step S1502, the AP1 sends a link reconfiguration response frame to the Non-AP STA, which carries a roaming preparation timeout t, indicating that the maximum or timeout duration for the AP2 to perform the roaming preparation operation (e.g., context transfer operation, data transfer operation) is t.

[0293] At step S1503, the STA initiates a roaming decision.

[0294] At step S1504, the STA sends the remaining MPDU to be sent to the AP1 to completion.

[0295] At step S1505, the STA sends an RAI frame to the AP1 to indicate that the roaming preparation operation is started. In addition, the roaming preparation timeout timer is started at the end of the Non-AP STA sending the RAI frame or the end of the AP1 receiving the ACK frame of the RAI frame, and the duration is t.

[0296] At step S1506, the context of the Non-AP STA is transferred from AP1 to AP2.

[0297] At step S1507, data path switching is performed between AP1 and AP2.

[0298] At step S1508, AP2 receives DL data sent by the controller to the Non-AP STA.

[0299] At step S1509, AP1 sends the remaining data packets to the Non-AP STA.

[0300] At step S1510, the RAR frame sent by AP1 cannot be successfully received by the Non-AP STA due to the long time failure of AP1 to obtain TXOP, or due to the dramatic change in the wireless channel quality between the Non-AP STA and AP1. When the t duration of the roaming preparation timeout timer expires, the Non-AP STA can no longer wait for the RAR frame, but actively establishes communication with AP2.

[0301] At step S1511, the Non-AP STA sends a roaming inquiry frame to AP2 to inquire whether the roaming preparation operation has been completed (this step is optional).

[0302] At step S1512, the Non-AP STA receives a roaming inquiry response frame sent by AP2 to obtain the inquiry result and various possible context contents (such as keys, BAs, protocols, etc.) (this step is optional).

[0303] At step S1513, UL / DL data transmission is performed between the Non-AP STA, AP2, and the controller.

[0304] Embodiment Three

[0305] Embodiment three is a seamless roaming signaling procedure based on non-co-located AP MLD.

[0306] In the roaming process, if the Non-AP STA (or Non-AP MLD) can only communicate with one AP MLD at the same time, and the Non-AP STA does not perform context transfer after sending the RAI frame, but immediately switches to the target AP, the signaling procedure of seamless roaming based on non-co-located AP MLD can be as shown in FIG. 16.

[0307] At step S1601, the Non-AP STA sends a link reconfiguration request frame to AP1 to request to add a link with AP2 but temporarily not to enable the link.

[0308] At step S1602, the AP1 sends a link reconfiguration response frame to the Non-AP STA, which carries the roaming preparation timeout time t, indicating that the AP2 performs the roaming preparation operation (e.g. context transfer operation, data transfer operation) with a timeout time t.

[0309] At step S1603, the STA initiates the roaming decision.

[0310] At step S1604, the STA sends the remaining MPDU to the AP1.

[0311] At step S1605, the STA sends a RAI frame to the AP1, indicating that the roaming preparation operation is started. In addition, the roaming preparation timeout timer is started at the end of the Non-AP STA sending the RAI frame or the end of the AP1 receiving the ACK frame of the RAI frame, with a time t.

[0312] At step S1606, the data path switching is performed between the AP1 and the AP2.

[0313] At step S1607, the AP2 receives the DL data sent by the controller to the STA.

[0314] At step S1608, the AP2 fails to send the RAR frame due to the AP2 failing to obtain the TXOP for a long time, or the RAR frame sent by the AP2 fails to be successfully received by the Non-AP STA due to the wireless channel quality between the Non-AP STA and the AP2 changing dramatically. When the time t of the roaming preparation timeout timer expires, the Non-AP STA can no longer wait for the RAR frame, but actively establishes communication with the AP2.

[0315] At step S1609, the Non-AP STA sends a roaming inquiry frame to the AP2 to inquire whether the roaming preparation operation has been completed (this step is optional).

[0316] At step S1610, the Non-AP STA receives the roaming inquiry response frame sent by the AP2 to obtain the inquiry result and various possible context contents (e.g. key, BA, protocol) (this step is optional).

[0317] At step S1611, the UL / DL data transmission is performed between the Non-AP STA, the AP2 and the controller.

[0318] Embodiment Four

[0319] Embodiment Four is a seamless roaming signaling procedure based on the Over-the-DS hot backup association, which can be as shown in FIG. 17.

[0320] At step S1701, the current AP MLD sends a beacon request to the Non-AP MLD.

[0321] At step S1702, the Non-AP MLD sends a probe request to the target AP MLD.

[0322] At step S1703, the target AP MLD sends a probe response to the Non-AP MLD, carrying a roaming preparation timeout time t, indicating that the timeout or maximum duration for the target AP MLD to perform the roaming preparation operation (e.g. context transfer operation, data transfer operation) is t.

[0323] At step S1704, the Non-AP MLD sends a beacon report to the current AP MLD.

[0324] At step S1705, the current AP MLD sends a BTM request to the Non-AP MLD.

[0325] At step S1706, the Non-AP MLD sends a BTM response to the current AP MLD.

[0326] At step S1707, the current AP MLD sends the FT request frame sent by the Non-AP MLD to the target AP MLD. In addition, at the end of the time when the Non-AP MLD sends the FT request frame or at the end of the time when the target AP MLD receives the ACK frame of the FT request frame, the roaming preparation timeout timer is started, with a duration of t.

[0327] At step S1708, due to insufficient channel time resources, the FT response frame is delayed and cannot be sent, or due to a dramatic change in wireless channel quality, the FT response frame cannot be successfully received by the Non-AP MLD. When the duration t of the roaming preparation timeout timer expires, the Non-AP MLD can no longer wait for the FT response frame, but actively establishes communication with the target AP MLD.

[0328] At step S1709, the Non-AP MLD can send a roaming query frame to the target AP MLD to inquire whether the roaming preparation operation has been completed (this step is optional).

[0329] At step S1710, the Non-AP MLD can receive a roaming query response frame sent by the target AP MLD to obtain the inquiry result (this step is optional).

[0330] At step S1711, the Non-AP MLD sends a DHCP discovery message to the target AP MLD.

[0331] At step S1712, the target AP MLD sends a DHCP Offer message to the Non-AP MLD.

[0332] At step S1713, the Non-AP MLD sends a DHCP Request message to the target AP MLD.

[0333] At step S1714, the target AP MLD sends a DHCP Ack message to the Non-AP MLD.

[0334] Embodiment Five

[0335] Embodiment Five is a cooperative roaming procedure by the target AP MLD, and the signaling procedure can be as shown in FIG. 18.

[0336] Referring to FIG. 18, at step S1801, the STA sends a link reconfiguration notification frame to the serving AP MLD, which can include one or more of the following: related information of multiple requested target AP MLDs, SMDE.

[0337] At step S1802, the nearly static context (e.g., protocol, capability) is transferred to multiple candidate target AP MLDs.

[0338] At step S1803, the target AP MLD acquires the key of the Non-AP MLD (if the key has not been installed). The key can include PMK, PTK.

[0339] At step S1804, the serving AP MLD sends a link reconfiguration notification frame to the STA. The link reconfiguration notification frame can include one or more of the following: related information of multiple candidate target AP MLDs and SMDE. In addition, the link reconfiguration notification frame can also carry a roaming preparation timeout time t to indicate that the maximum or timeout length of the target AP MLD performing the roaming preparation operation (e.g., context transfer operation, data transfer operation) is t.

[0340] At step S1805, the RSSI of the STA decreases, and decides to roam to the target AP MLD.

[0341] At step S1806, the STA sends a link reconfiguration request frame to the target AP MLD, which is sent in PMF form. In addition, the roaming preparation timeout timer is started at the end of the STA sending the link reconfiguration request frame or the end of the target AP MLD receiving the ACK frame of the link reconfiguration request frame, with a length of t.

[0342] At step S1807a, the target AP MLD requests context transfer from the serving AP MLD. Since the nearly static context has been transferred previously, the dynamic context (e.g., SN, PN, BA, etc.) is mainly transferred at this time.

[0343] At step S1807b, the target AP MLD enables the DS mapping.

[0344] At step S1807c, the target AP MLD requests data transmission from the serving AP MLD (this step is optional).

[0345] At step S1808, due to the long time failure of the target AP MLD to obtain the TXOP, the link reconfiguration response frame fails to be sent, or due to the drastic change of the wireless channel quality between the STA and the target AP MLD, the link reconfiguration response frame fails to be successfully received by the STA. When the time length t of the roaming preparation timeout timer expires, the STA can no longer wait for the link reconfiguration response frame, and actively establishes communication with the target AP MLD.

[0346] At step S1809, the STA sends a roaming inquiry frame to the target AP MLD to inquire whether the roaming preparation operation has been completed (this step is optional).

[0347] At step S1810, the STA receives a roaming inquiry response frame sent by the target AP MLD to obtain the inquiry result and various possible context contents (this step is optional).

[0348] At step S1811, the STA and the target AP MLD perform UL / DL data transmission.

[0349] Embodiment Six

[0350] Embodiment Six is SMD roaming based on non-collocated AP MLDs, and the signaling flow of the roaming can be as shown in FIG. 19.

[0351] At step S1901, the STA initiates association with the SMD through interaction (re)association request / response with the serving AP MLD.

[0352] At step S1902, the STA and the serving AP MLD perform 802.1X / EAP authentication, and the authentication process can skip the PSK acquisition process and the SAE process.

[0353] At step S1903, the STA and the serving AP MLD generate a PMK.

[0354] At step S1904, the STA and the serving AP MLD perform four-way handshake.

[0355] In step S1905, the STA and the serving AP MLD generate a PTK.

[0356] In step S1906, the STA sends a roaming preparation request frame to the serving AP MLD to request to establish a link with multiple candidate target AP MLDs.

[0357] In step S1907, the serving AP MLD performs roaming context transfer with the candidate target AP MLD. The context to be transferred here can include a link, a quasi-static context, a capability, etc.

[0358] In step S1908, the candidate target AP MLD installs a PMK and a PTK.

[0359] In step S1909, the serving AP MLD sends a roaming preparation response frame to the STA. The roaming preparation response frame can carry a roaming preparation timeout time t to indicate that the maximum or timeout time length for the target AP MLD to perform a roaming preparation operation (such as a context transfer operation, a data transfer operation) is t.

[0360] In step S1910, the STA transmits UL data between the STA and the serving AP MLD.

[0361] In step S1911, the STA sends a roaming request frame to the serving AP MLD. The roaming request frame can be PMF-protected.

[0362] In step S1912, the serving AP MLD performs roaming context transfer with the target AP MLD. The context to be transferred here can include an SN, a PN, and a BA context.

[0363] In step S1913, the target AP MLD enables DS mapping.

[0364] In step S1914, the target AP MLD opens an 802.1X port.

[0365] In step S1915, the serving AP MLD fails to send a roaming response due to a long time of failure to obtain a TXOP, or the STA fails to successfully receive the roaming response due to a dramatic change in wireless channel quality between the STA and the serving AP MLD. When the time length t of the roaming preparation timeout timer expires, the STA can no longer wait for the roaming response, but actively establishes communication with the target AP MLD.

[0366] In step S1916, the STA sends a roaming inquiry frame to the target AP MLD to inquire whether the roaming preparation operation has been completed (this step is optional).

[0367] At step S1917, the STA receives the roaming query response frame sent by the target AP MLD to obtain the query result and various possible context contents (this step is optional).

[0368] At step S1918, the STA and the target AP MLD perform UL / DL data transmission.

[0369] At step S1919, the serving AP MLD sends the buffered DL data to the STA.

[0370] At step S1920, the serving AP MLD notifies the target AP MLD that the delivery of the DL data buffered by the serving AP MLD is completed or timed out.

[0371] At steps S1921-S1922, the STA and the target AP MLD re-generate the PTK.

[0372] The method embodiments of the present application are described in detail above, and the device embodiments of the present application are described in detail below. It should be understood that the description of the method embodiments and the description of the device embodiments correspond to each other, and therefore, the parts not described in detail can be referred to the method embodiments described above.

[0373] FIG. 20 is a schematic structural diagram of a communication device 2000 according to an embodiment of the present application. The communication device 2000 is a first STA, and the first STA includes a receiving unit 2010. The receiving unit 2010 is configured to receive a first frame sent by a first AP, wherein the first frame includes first time information, and the first time information is used by the first STA to determine a first time in a roaming process from a source AP to a target AP, and the first time is a time at which the first STA is allowed to start communication with the target AP.

[0374] In the embodiments of the present application, the communication device 2000 described above can be used to perform part or all of the method steps performed by the first STA in the method embodiments described above. The communication device 2000 includes units or modules for performing the method steps described above. The method flow has been described in detail in the foregoing embodiments, and the modules in the present embodiment have the same functions or perform the same steps, which will not be described here again. However, as a person skilled in the art should know that the corresponding textual description of the foregoing method embodiments can be introduced into the present embodiment, and the modules in the communication device 2000 correspond thereto.

[0375] In optional embodiments, the receiving unit 2010 can be a transceiver 2230. The communication device 2000 can further include a processor 2210 and a memory 2220, as shown in FIG. 22.

[0376] FIG. 21 is a schematic structural diagram of a communication device 2100 provided in an embodiment of the present application. The communication device 2100 is a first AP, and the first AP includes a sending unit 2110. The sending unit 2110 is configured to send a first frame to a first STA, where the first frame includes first time information, and the first time information is used by the first STA to determine a first time in a roaming process from a source AP to a target AP, and the first time is a time at which the first STA is allowed to start communication with the target AP.

[0377] In the embodiments of the present application, the communication device 2100 described above can be used to execute part or all of the method steps performed by the first STA in the method embodiments described above. The communication device 2100 includes units or modules for executing the method steps described above. The method flow has been described in detail in the foregoing embodiments, and the modules in this embodiment have the same functions or execute the same steps, which will not be described here in detail. However, it should be known by those skilled in the art that the corresponding textual description of the foregoing method embodiments can be introduced into the present embodiment, and the modules in the communication device 2100 correspond thereto.

[0378] In optional embodiments, the sending unit 2110 can be a transceiver 2230. The communication device 2100 can further include a processor 2210 and a memory 2220, as shown in FIG. 22.

[0379] FIG. 22 is a schematic structural diagram of a communication device according to an embodiment of the present application. The dashed line in FIG. 22 indicates that the unit or module is optional. The device 2200 can be used to implement the methods described in the method embodiments described above. The device 2200 can be a chip or a communication device.

[0380] The device 2200 can include one or more processors 2210. The processor 2210 can support the device 2200 to implement the methods described in the foregoing method embodiments. The processor 2210 can be a general purpose processor or a dedicated processor. For example, the processor can be a central processing unit (CPU). Alternatively, the processor can also be other general purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs) or other programmable logic devices, discrete gates or transistor logic components, discrete hardware components, etc. The general purpose processor can be a microprocessor or the processor can also be any conventional processor.

[0381] The apparatus 2200 can further include one or more memories 2220. The memories 2220 store a program for execution by the processor 2210, such that the processor 2210 performs the methods described in the foregoing method embodiments. The memories 2220 can be independent of the processor 2210 or integrated in the processor 2210.

[0382] The apparatus 2200 can further include a transceiver 2230. The processor 2210 can communicate with other devices or chips through the transceiver 2230. For example, the processor 2210 can perform data transceiving with other devices or chips through the transceiver 2230.

[0383] Embodiments of the present application also provide a computer readable storage medium for storing a program. The computer readable storage medium can be applied in the communication device provided by the embodiments of the present application, and the program causes the computer to perform the method performed by the communication device in the various embodiments of the present application.

[0384] Embodiments of the present application also provide a computer program product. The computer program product includes a program. The computer program product can be applied in the communication device provided by the embodiments of the present application, and the program causes the computer to perform the method performed by the communication device in the various embodiments of the present application.

[0385] Embodiments of the present application also provide a computer program. The computer program can be applied in the communication device provided by the embodiments of the present application, and the computer program causes the computer to perform the method performed by the communication device in the various embodiments of the present application.

[0386] It should be understood that the terms "system" and "network" can be used interchangeably in the present application. In addition, the terms used in the present application are only used to explain the specific embodiments of the present application, and are not intended to limit the present application. The terms "first", "second", "third", and "fourth" and the like in the specification and claims of the present application and the drawings are used to distinguish different objects, and are not used to describe a particular order. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion.

[0387] In the embodiments of the present application, a "field" can also be referred to as a "domain", a "subfield", or a "sub-domain". A field can occupy one or more bytes (octets), or a field can occupy one or more bits (bits).

[0388] The field name defined in the embodiments of the present application is only an example, and the field can have other names.

[0389] In the embodiments of the present application, the "indication" can be direct indication, indirect indication, or can represent an associated relationship. For example, A indicates B, which can mean that B can be obtained by A; or A indirectly indicates B, for example, A indicates C, and B can be obtained by C; or A and B have an associated relationship.

[0390] In the embodiments of the present application, "B corresponding to A" means that B is associated with A, and B can be determined according to A. However, it should also be understood that determining B according to A does not mean that B is determined only according to A, but B can also be determined according to A and / or other information.

[0391] In the embodiments of the present application, the term "corresponding" can represent a direct or indirect corresponding relationship between the two, or can represent an associated relationship between the two, or can represent an indication and being indicated, configuration and being configured, and the like.

[0392] In the embodiments of the present application, "predefined" or "preconfigured" can be implemented by pre-saving corresponding codes, tables or other information that can be used to indicate related information in devices (for example, including AP and STA), and the specific implementation manner is not limited in the present application. For example, predefinition can mean definition in a protocol.

[0393] In the embodiments of the present application, the term "and / or" is only used to describe the associated relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which can mean that A exists alone, A and B exist together, and B exists alone. In addition, the character " / " in this paper generally represents an "or" relationship between the associated objects before and after it.

[0394] In the embodiments of the present application, the "including" can mean direct including or indirect including. Alternatively, the "including" mentioned in the embodiments of the present application can be replaced by "indicating" or "used for determining". For example, A includes B can be replaced by A indicating B, or A used for determining B.

[0395] In various embodiments of the present application, the size of the serial number of the above processes does not mean the execution order, and the execution order of the processes should be determined according to its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0396] In the embodiments of the present application, the "protocol" can mean a standard protocol in the communication field, for example, it can include WIFI protocol and related protocols applied to future WIFI communication systems, and the present application does not limit this.

[0397] In several embodiments provided in the present application, it should be understood that the disclosed system, device and method can be implemented by other manners. For example, the above-described device embodiments are merely illustrative, for example, the division of the units is merely a logical function division, and in actual implementation, another division manner can be adopted, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the units shown or discussed can be indirect coupling or communication connection through some interfaces, devices or units, and can be electrical, mechanical or other forms.

[0398] The units described as separate components can or can not be physically separate, and the components shown as units can or can not be physical units, i.e., can be located in one place or distributed on a plurality of network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiment.

[0399] In addition, the functional units in each embodiment of the present application can be integrated in one processing unit, or each unit can be physically present separately, or two or more units can be integrated in one unit.

[0400] In the above embodiments, all or part can be realized by software, hardware, firmware or any combination thereof. When realized by software, all or part can be realized in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of the present application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network or other programmable devices. The computer instructions can be stored in a computer readable storage medium or transferred from one computer readable storage medium to another, for example, the computer instructions can be transferred from one website, computer, server or data center to another website, computer, server or data center through wired (such as coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (such as infrared, wireless, microwave, etc.) manner. The computer readable storage medium can be any available medium readable by a computer or a data storage device such as a server, data center, etc. integrated with one or more available media. The available media can be magnetic media (such as floppy disk, hard disk, magnetic tape), optical media (such as digital video disc (DVD)) or semiconductor media (such as solid state disk (SSD)) and the like.

[0401] The above descriptions are only the specific embodiments of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can easily think of the changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A communication method characterized by comprising: Comprising: A first station (STA) receives a first frame sent by a first access point (AP), the first frame comprising first time information used in a roaming process of the first STA.

2. The method of claim 1, wherein, The first time information is used to determine a first time in the roaming process, the first time being a time when the first STA is allowed to start communicating with a target AP.

3. The method according to claim 1 or 2, characterized in that, The first time information is used to indicate one or more of: a time duration required for a target AP in the roaming process to perform a roaming preparation operation; a time interval with a second time as a starting time; wherein the second time is determined based on a sending time of a second frame, the second frame being used to request roaming from a source AP to the target AP or the second frame being used to trigger the target AP to perform the roaming preparation operation.

4. The method of claim 3, wherein, an end time of the time interval being the time when the first STA is allowed to start communicating with the target AP.

5. The method according to claim 3 or 4, characterized in that, The time duration required for the target AP to perform the roaming preparation operation comprises a maximum time duration required for the target AP to perform the roaming preparation operation.

6. The method according to any one of claims 3 to 5, characterized in that, The second time is the sending time of the second frame or a receiving time of an acknowledgement frame of the second frame.

7. The method according to any one of claims 3 to 6, characterized in that, Within the time interval, if the first STA does not receive a response frame of the second frame, the first STA is allowed to start communicating with the target AP.

8. The method according to any one of claims 3 to 7, characterized in that, Within the time interval, if the first STA does not receive a response frame of the second frame, the first STA is allowed to send a third frame to the target AP; wherein the third frame is used to inquire whether the roaming preparation operation is completed; and / or, the third frame is used to request information in the response frame of the second frame.

9. The method according to any one of claims 3 to 8, characterized in that, The second frame comprises a roam announce information frame, a fast basic service set transition (FT) request frame, a link reconfiguration request frame, or a roam request frame.

10. The method according to any one of claims 3 to 9, characterized in that, The roaming preparation operation comprises one or more of: a context transfer operation of the first STA, a data transfer operation of the first STA.

11. The method according to any one of claims 1 to 10, characterized in that, The first frame comprises a roam preparation response frame, a link reconfiguration notification frame, a link reconfiguration response frame, or a probe response frame.

12. The method of claim 11, wherein, The first frame comprises a link reconfiguration notification frame, the link reconfiguration notification frame comprising a reconfiguration multi-link element field, and the first time information is carried in the reconfiguration multi-link element field.

13. The method of claim 12, wherein, The reconfiguration multi-link element field comprises a link information field, and the first time information is carried in the link information field.

14. The method of claim 13, wherein, The link information field comprises an STA information field, and the STA information field comprises a first field used to carry the first time information.

15. The method of claim 14, wherein, The link information field further comprises an STA control field, and the STA control field comprises a second field used to indicate whether the STA information field contains the first field.

16. The method of claim 11, wherein, The first frame comprises a link reconfiguration response frame, the link reconfiguration response frame comprising a basic multi-link element field, and the first time information is carried in the basic multi-link element field.

17. The method of claim 16, wherein, The basic multi-link element field comprises a link information field, and the first time information is carried in the link information field.

18. The method of claim 17, wherein, The link information field comprises an STA information field, and the STA information field comprises a third field used for carrying the first time information.

19. The method of claim 18, wherein, The link information field further comprises an STA control field, and the STA control field comprises a fourth field used for indicating whether the STA information field contains the third field.

20. The method of any one of claims 1 to 19, wherein, The first AP is a source AP or a target AP in the roaming process.

21. The method of any one of claims 1-20, wherein: The first STA is a non-AP STA or a non-AP multi-link device (MLD); and / or The first AP is an AP STA or an AP MLD.

22. A method of communication, comprising: Comprising: A first access point (AP) sends a first frame to a first station (STA), and the first frame comprises first time information used in a roaming process of the first STA.

23. The method of claim 22, wherein, The first time information is used to determine a first time in the roaming process, and the first time is a time at which the first STA is allowed to start communicating with a target AP.

24. The method of claim 22 or 23, wherein, The first time information is used to indicate one or more of: a time length required for a target AP in the roaming process to perform a roaming preparation operation; a time interval with a second time as a starting time; wherein the second time is determined based on a transmission time of a second frame used for requesting roaming from the source AP to the target AP or triggering the target AP to perform the roaming preparation operation.

25. The method of claim 24, wherein, An end time of the time interval is a time at which the first STA is allowed to start communicating with the target AP.

26. The method of claim 24 or 25, wherein, The time length required for the target AP to perform the roaming preparation operation comprises a maximum time length required for the target AP to perform the roaming preparation operation.

27. The method of any one of claims 24-26, wherein, The second time is the transmission time of the second frame or a reception time of an acknowledgement frame of the second frame.

28. The method of any one of claims 24-27, wherein, Within the time interval, if the first STA does not receive a response frame of the second frame, the first STA is allowed to start communicating with the target AP.

29. The method according to any one of claims 24 to 28, characterized in that, Within the time interval, if the first STA does not receive a response frame of the second frame, the first STA is allowed to send a third frame to the target AP; wherein the third frame is used to inquire whether the roaming preparation operation is completed; and / or the third frame is used to request information in the response frame of the second frame.

30. The method of any one of claims 24-29, wherein, The second frame comprises a roaming announcement information frame, a fast basic service set transition (FT) request frame, a link reconfiguration request frame, or a roaming request frame.

31. The method of any one of claims 24-30, wherein, The roaming preparation operation comprises one or more of: a context transfer operation of the first STA, or a data transfer operation of the first STA.

32. The method of any one of claims 22-31, wherein, The first frame comprises a roaming preparation response frame, a link reconfiguration notification frame, a link reconfiguration response frame, or a probe response frame.

33. The method of claim 32, wherein, The first frame comprises a link reconfiguration notification frame, and the link reconfiguration notification frame comprises a reconfiguration multi-link element field, and the first time information is carried in the reconfiguration multi-link element field.

34. The method of claim 33, wherein, The reconfiguration multi-link element field comprises a link information field, and the first time information is carried in the link information field.

35. The method of claim 34, wherein, The link information field comprises an STA information field, and the STA information field comprises a first field used to carry the first time information.

36. The method of claim 35, wherein, The link information field further comprises an STA control field, and the STA control field comprises a second field used to indicate whether the STA information field contains the first field.

37. The method of claim 32, wherein, The first frame comprises a link reconfiguration response frame, and the first time information is carried in a basic multi-link element field in the link reconfiguration response frame.

38. The method of claim 37, wherein, The basic multi-link element field comprises a link information field, and the first time information is carried in the link information field.

39. The method of claim 38, wherein, The link information field comprises an STA information field, and the STA information field comprises a third field used to carry the first time information.

40. The method of claim 39, wherein, The link information field further comprises an STA control field, and the STA control field comprises a fourth field used to indicate whether the STA information field contains the third field.

41. The method of any one of claims 22-40, wherein, The first AP is a source AP or a target AP in the roaming process.

42. The method of any one of claims 22-41, wherein: The first STA is a non-AP STA or a non-AP multi-link device (MLD); and / or The first AP is an AP STA or an AP MLD.

43. A communications device, characterized by The communication device is a first station (STA), and the first STA comprises: a receiving unit configured to receive a first frame sent by a first access point (AP), wherein the first frame comprises first time information used in a roaming process of the first STA.

44. The apparatus of claim 43, wherein, The first time information is used to determine a first time in the roaming process, and the first time is a time at which the first STA is allowed to start communicating with a target AP.

45. The apparatus of claim 43 or 44, wherein, The first time information is used to indicate one or more of the following: a time length required for a target AP in the roaming process to perform a roaming preparation operation; a time interval with a second time as a starting time; wherein the second time is determined based on a sending time of a second frame used to request roaming from the source AP to the target AP or the second frame used to trigger the target AP to perform the roaming preparation operation.

46. The apparatus of claim 45, wherein, An ending time of the time interval is a time at which the first STA is allowed to start communicating with the target AP.

47. The apparatus of claim 45 or 46, wherein, The time length required for the target AP to perform the roaming preparation operation comprises a maximum time length required for the target AP to perform the roaming preparation operation.

48. The apparatus of any one of claims 45-47, wherein, The second time is the sending time of the second frame or a receiving time of an acknowledgement frame of the second frame.

49. The apparatus of any one of claims 45-48, wherein, If the first STA does not receive a response frame of the second frame within the time interval, the first STA is allowed to start communicating with the target AP.

50. The apparatus of any one of claims 45-49, wherein, If the first STA does not receive a response frame of the second frame within the time interval, the first STA is allowed to send a third frame to the target AP; wherein the third frame is used to inquire whether the roaming preparation operation is completed; and / or the third frame is used to request information in the response frame of the second frame.

51. The apparatus of any one of claims 45-50, wherein, The second frame comprises a roam announce information frame, a fast basic service set transition (FT) request frame, a link reconfiguration request frame, or a roam request frame.

52. The apparatus of any one of claims 45-51, wherein, The roam preparation operation comprises one or more of: a context transfer operation of the first STA, or a data transfer operation of the first STA.

53. The apparatus of any one of claims 43-52, wherein, The first frame comprises a roam preparation response frame, a link reconfiguration notification frame, a link reconfiguration response frame, or a probe response frame.

54. The apparatus of claim 53, wherein, The first frame comprises a link reconfiguration notification frame, the link reconfiguration notification frame comprising a reconfiguration multi-link element field, and the first time information is carried in the reconfiguration multi-link element field.

55. The apparatus of claim 54, wherein, The reconfiguration multi-link element field comprises a link information field, and the first time information is carried in the link information field.

56. The apparatus of claim 55, wherein, The link information field comprises a STA information field, and the STA information field comprises a first field used to carry the first time information.

57. The apparatus of claim 56, wherein, The link information field further comprises a STA control field, and the STA control field comprises a second field used to indicate whether the STA information field contains the first field.

58. The apparatus of claim 53, wherein, The first frame comprises a link reconfiguration response frame, the link reconfiguration response frame comprising a basic multi-link element field, and the first time information is carried in the basic multi-link element field.

59. The apparatus of claim 58, wherein, The basic multi-link element field comprises a link information field, and the first time information is carried in the link information field.

60. The apparatus of claim 59, wherein, The link information field comprises a STA information field, and the STA information field comprises a third field used to carry the first time information.

61. The apparatus of claim 60, wherein, The link information field further comprises a STA control field, and the STA control field comprises a fourth field used to indicate whether the STA information field contains the third field.

62. The apparatus of any one of claims 43-61, wherein, The first AP is a source AP or a target AP in the roaming process.

63. The device of any of claims 43-62, wherein: The first STA is a non-AP STA or a non-AP multi-link device (MLD); and / or The first AP is an AP STA or an AP MLD.

64. A communications device, characterized by The communication device is a first access point (AP), and the first AP comprises: a sending unit configured to send, to a first station (STA), a first frame, the first frame comprising first time information used in a roaming process of the first STA.

65. The apparatus of claim 64, wherein, The first time information is used to determine a first time in the roaming process, the first time being a time at which the first STA is allowed to start communicating with a target AP.

66. The apparatus of claim 64 or 65, wherein, The first time information is used to indicate one or more of: a time length required for a target AP in the roaming process to perform a roam preparation operation; a time interval with a second time as a starting time; wherein the second time is determined based on a sending time of a second frame, the second frame being used to request roaming from the source AP to the target AP or the second frame being used to trigger the target AP to perform the roam preparation operation.

67. The apparatus of claim 66, wherein, An ending time of the time interval is the time at which the first STA is allowed to start communicating with the target AP.

68. The apparatus of claim 66 or 67, wherein, The time length required for the target AP to perform the roaming preparation operation includes a maximum time length required for the target AP to perform the roaming preparation operation.

69. The apparatus of any one of claims 66-68, wherein, The second time is a sending time of the second frame or a receiving time of an acknowledgement frame of the second frame.

70. The apparatus of any one of claims 66-69, wherein, If the first STA does not receive a response frame of the second frame within the time interval, the first STA is allowed to start communicating with the target AP.

71. The apparatus of any one of claims 66-70, wherein, If the first STA does not receive a response frame of the second frame within the time interval, the first STA is allowed to send a third frame to the target AP. The third frame is used to inquire whether the roaming preparation operation is completed; and / or the third frame is used to request information in the response frame of the second frame.

72. The apparatus of any one of claims 66-71, wherein, The second frame includes a roaming announcement information frame, a fast basic service set transfer (FT) request frame, a link reconfiguration request frame, or a roaming request frame.

73. The apparatus of any one of claims 66-72, wherein, The roaming preparation operation includes one or more of a context transfer operation of the first STA or a data transfer operation of the first STA.

74. The apparatus of any one of claims 64-73, wherein, The first frame includes a roaming preparation response frame, a link reconfiguration notification frame, a link reconfiguration response frame, or a probe response frame.

75. The apparatus of claim 74, wherein, The first frame includes a link reconfiguration notification frame, and the link reconfiguration notification frame includes a reconfiguration multi-link element field, and the first time information is carried in the reconfiguration multi-link element field.

76. The apparatus of claim 75, wherein, The reconfiguration multi-link element field includes a link information field, and the first time information is carried in the link information field.

77. The apparatus of claim 76, wherein, The link information field includes an STA information field, and the STA information field includes a first field used to carry the first time information.

78. The apparatus of claim 77, wherein, The link information field further includes an STA control field, and the STA control field includes a second field used to indicate whether the STA information field contains the first field.

79. The apparatus of claim 74, wherein, The first frame includes a link reconfiguration response frame, and the link reconfiguration response frame includes a basic multi-link element field, and the first time information is carried in the basic multi-link element field.

80. The apparatus of claim 79, wherein, The basic multi-link element field includes a link information field, and the first time information is carried in the link information field.

81. The apparatus of claim 80, wherein, The link information field includes an STA information field, and the STA information field includes a third field used to carry the first time information.

82. The apparatus of claim 81, wherein, The link information field further includes an STA control field, and the STA control field includes a fourth field used to indicate whether the STA information field contains the third field.

83. The apparatus of any one of claims 64-82, wherein, The first AP is a source AP or a target AP in the roaming process.

84. The device of any one of claims 64-83, wherein: The first STA is a non-AP STA or a non-AP multi-link device (MLD); and / or The first AP is an AP STA or an AP MLD.

85. A communications device, characterized by A communication device comprising a transceiver, a memory for storing a program, and a processor for invoking the program in the memory and controlling the transceiver to receive or send signals, so as to make the communication device perform the method of any one of claims 1-21 or the method of any one of claims 22-42.

86. An apparatus comprising: A device comprising a processor for invoking a program from a memory, so as to make the device perform the method of any one of claims 1-21 or the method of any one of claims 22-42.

87. A chip, comprising: A chip comprising a processor for invoking a program from a memory, so that the device installed with the chip performs the method of any one of claims 1-21 or the method of any one of claims 22-42.

88. A computer-readable storage medium, characterized in that, A computer program stored on a computer readable medium, the program causing a computer to perform the method of any one of claims 1-21 or the method of any one of claims 22-42.

89. A computer program product, characterised in that, A computer program product comprising a program, the program causing a computer to perform the method of any one of claims 1-21 or the method of any one of claims 22-42.

90. A computer program, characterized in that, The computer program causes a computer to perform the method of any one of claims 1-21 or the method of any one of claims 22-42.

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