Wireless local area network system, method and communication device

Abstract

The invention discloses a wireless local area network system, which comprises a plurality of access points, BSSIDs carried by beacon frames sent by the plurality of access points are the same, and the beacon frames are sent by adopting relatively high modulation orders. For example, the plurality of access points include a first access point and a second access point; the first access point is used for sending a first beacon frame, the first beacon frame is modulated by adopting a first modulation order and comprises a first BSSID, the second access point is used for sending a second beacon frame, the second beacon frame is modulated by adopting a second modulation order and comprises the first BSSID. The first modulation order and the second modulation order are both higher than or equal to a modulation order threshold. Thus, if the signal strength of the beacon frame sent by the access point is weak, the terminal cannot receive the beacon frame from the access point, so that the roaming process cannot be triggered due to the weak signal strength of the received beacon frame, and the service transmission delay is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of wireless local area network (WLAN), and in particular to a wireless local area network system, method and communication device. Background Art

[0002] A WLAN system includes at least one access point (AP) and at least one terminal. Due to the mobility of the terminal, the terminal may move from the coverage of one AP to the coverage of another AP. In order to ensure the service continuity and communication quality of the terminal, the terminal needs to roam, that is, the terminal needs to switch between different APs.

[0003] However, frequent switching of terminals between multiple APs will cause long service transmission delays and even packet loss, seriously affecting services. Summary of the invention

[0004] The present application provides a WLAN system, method and communication device for reducing the number of times a terminal triggers roaming, thereby reducing service transmission delay.

[0005] In a first aspect, the present application provides a WLAN system, which includes multiple access points, including a first access point and a second access point. The first access point is used to send a first beacon frame, and the first beacon frame includes an identifier (ID) of a first basic service set (basic service set, BSS). The second access point is used to send a second beacon frame, and the second beacon frame includes a first BSSID. The first beacon frame is modulated with a first modulation order, and the second beacon frame is modulated with a second modulation order. Both the first modulation order and the second modulation order are higher than or equal to a modulation order threshold.

[0006] In this scheme, the modulation order threshold can be (pre) configured. The first modulation order and the second modulation order are both higher than or equal to the modulation order threshold. It can be considered that the first access point and the second access point both use a higher modulation order to modulate the sent beacon frame. The higher the modulation order, the greater the signal strength required for the receiving end to demodulate the received signal normally. In this way, when the signal strength of the beacon frame sent by a certain access point is weak, the receiving end (such as the terminal) cannot demodulate the beacon frame sent by the access point or cannot receive the beacon frame with weak signal strength. This scheme can filter out beacon frames with weak signal strength for the terminal. For the terminal, the signal strength of the received beacon frames is strong, which can reduce the terminal triggering the roaming process, reduce the service transmission delay, and reduce packet loss.

[0007] In one implementation, the modulation order threshold is determined according to a signal strength threshold.

[0008] By determining the modulation order threshold according to the signal strength threshold, it is possible to clearly filter out beacon frames of what signal strength, so that the modulation order used by the access point can filter out an appropriate number of beacon frames, thereby minimizing the number of terminal-triggered roaming while ensuring network coverage as much as possible.

[0009] In one implementation, the modulation order threshold is greater than or equal to the modulation order corresponding to the signal strength threshold, and the modulation order corresponding to the signal strength threshold is: when the corresponding modulation order is used to modulate the signal, if the signal strength of the signal received by the receiving end is greater than or equal to the signal strength threshold, the receiving end can demodulate the received signal.

[0010] In one implementation, the signal strength threshold is determined according to the signal strength corresponding to the terminal triggering roaming. The signal strength corresponding to the terminal triggering roaming means that when the signal strength is less than or equal to this value, the terminal will disconnect from the current associated AP and try to associate with other APs.

[0011] By determining the signal strength threshold according to the signal strength corresponding to the terminal triggering roaming, the appropriate modulation order threshold can be determined more accurately, thereby ensuring network coverage as much as possible while reducing the terminal triggering roaming.

[0012] In one implementation, the signal strength corresponding to the terminal triggering roaming is also determined according to the operating channel bandwidth of the terminal. The signal strength threshold is adaptively adjusted according to the operating channel bandwidth of the terminal to obtain a more appropriate modulation order threshold as much as possible.

[0013] In one implementation, the first modulation order and the second modulation order are both higher than or equal to 64-quadrature amplitude modulation (QAM).

[0014] In one implementation, when the first duration is greater than a preset duration, the second access point sends the second beacon frame. The first duration is the time interval between a first moment and a second moment, the first moment is the moment when the second access point most recently receives a beacon frame carrying the first BSSID, and the second moment is the moment when the second access point last sends a beacon frame carrying the first BSSID, or the second moment is the moment when the second access point last receives a beacon frame that triggers the second access point to send a beacon frame carrying the first BSSID.

[0015] In this solution, the interval between two consecutive beacon frame transmissions by the second access point is greater than a preset time length, which can prevent the second access point from transmitting beacon frames multiple times within a beacon transmission cycle, that is, preventing the beacon frames from being transmitted in an infinite loop.

[0016] In one implementation, if the second access point has not sent a beacon frame, then when receiving a beacon frame from another access point, the second access point sends a second beacon frame.

[0017] In one implementation, the signal strength of the most recently received beacon frame carrying the first BSSID is lower than a preset threshold.

[0018] In this solution, the second access point sends the second beacon frame only when the signal strength of the received beacon frame is lower than the preset threshold. This ensures that fewer access points send beacon frames, which can further reduce the possibility of the terminal triggering the roaming process.

[0019] In one implementation, the preset duration is less than the beacon transmission period, and the preset duration is greater than the total duration of the channel occupied by at least one access point in the WLAN system to transmit a beacon frame, so that the access point can send a beacon frame once in one beacon transmission period as much as possible.

[0020] In one implementation, the first beacon frame and the second beacon frame carry the same timestamp.

[0021] In this solution, the first beacon frame can be a beacon frame sent by the master access point, and the second beacon frame can be a beacon frame sent by the slave access point. The first beacon frame and the second beacon frame carry the same timestamp, which is beneficial to reducing terminal packet loss and can also reduce the processing complexity of the slave access point.

[0022] In a second aspect, the present application provides another WLAN system, the WLAN system comprising a plurality of access points and a terminal device, the plurality of access points comprising a first access point and a second access point. The first access point is used to send a first beacon frame at a first time, the first beacon frame comprising a first BSSID. The second access point is used to send a second beacon frame at a second time, the second beacon frame comprising a first BSSID. The first time is the same as the second time, or the time interval between the first time and the second time is less than a preset interval. The terminal is used to receive a third beacon frame, the third beacon frame being obtained according to the first beacon frame and the second beacon frame.

[0023] In this solution, access points send beacon frames at the same or similar time, so that the terminal can superimpose beacon frames from different access points to obtain beacon frames with stronger signal strength, which can reduce the terminal triggering roaming process.

[0024] In one implementation, the third beacon frame is obtained according to the first beacon frame and the second beacon frame, including: a signal carrying the third beacon frame is a superposition of a signal carrying the first beacon frame and a signal carrying the second beacon frame.

[0025] In one implementation, the second beacon frame and the first beacon frame each include the same content, scrambling code, and modulation and coding scheme (MCS), so that the first beacon frame and the second beacon frame can form a multipath effect, so that the signal strength of the third beacon frame obtained by the terminal is greater.

[0026] In one implementation, the first access point is further used to: receive a timing synchronization frame from a third access point, where the timing synchronization frame is used to trigger the access point receiving the timing synchronization frame to send a first beacon frame.

[0027] In this solution, each access point sends a beacon frame triggered by a timing synchronization frame, and each access point sends a beacon frame after receiving the timing synchronization frame. This solution allows each access point to send a beacon frame at the same or similar time to form a multipath effect.

[0028] In one implementation, the timing synchronization frame includes a timestamp, and the timestamp instructs the access point receiving the timing synchronization frame to add the timestamp to the beacon frame to be sent. In this way, the beacon frames sent by each access point can include the same content to achieve a multipath effect.

[0029] In one implementation, the first time and the second time are both scheduled beacon transmission times, and the scheduled beacon transmission times of different access points are the same. In this solution, each access point transmits a beacon frame when its scheduled beacon transmission time is reached, thereby ensuring that each access point transmits a beacon frame at the same time as much as possible.

[0030] In one implementation, the interval between the first time and the second time is less than a preset interval. The first time and the second time may be close in time.

[0031] In one implementation, the preset interval is less than or equal to a guard interval (GI), and the time synchronization accuracy between the first access point and the second access point is higher than the GI.

[0032] In this solution, when the time synchronization accuracy between the first access point and the second access point is higher than the GI, the first time and the second time can be guaranteed to be the same or close. Each access point can be synchronized in advance, and the timestamp carried by the beacon frame sent by each access point can be the system time obtained from the respective system clock, which has low complexity.

[0033] In a third aspect, the present application provides a beacon frame sending method, which is performed by a first communication device. The first communication device may be an access point, or the first communication device may be a component for implementing the functions of an access point. For example, the first communication device may be a unit / module, a circuit or a chip inside the access point. The method provided in the third aspect is described below by taking the first communication device as the access point itself as an example. Of course, the method provided in the third aspect may also be implemented by a unit / module, a circuit or a chip inside the access point. The access point is an access point in the WLAN system of the first aspect, and the beneficial effects can be referred to the description of the first aspect and will not be repeated here.

[0034] The method comprises: an access point generates a first beacon frame and sends the first beacon frame, wherein the first beacon frame comprises a first BSSID and is modulated by a first modulation order, wherein the first modulation order is higher than or equal to a modulation order threshold.

[0035] In one implementation, the modulation order threshold is determined according to a signal strength threshold.

[0036] In one implementation, the signal strength threshold is determined according to the signal strength corresponding to the terminal triggering roaming.

[0037] In one implementation, the modulation order threshold is greater than or equal to the modulation order corresponding to the signal strength threshold, and the modulation order corresponding to the signal strength threshold is: when the corresponding modulation order is used to modulate the signal, if the signal strength of the signal received by the receiving end is greater than or equal to the signal strength threshold, the receiving end can demodulate the received signal.

[0038] In one implementation, when the first duration is greater than a preset duration, the access point sends the first beacon frame. The first duration is the time interval between a first moment and a second moment, the first moment is the moment when the access point most recently receives a beacon frame carrying the first BSSID, and the second moment is the moment when the access point last sends a beacon frame carrying the first BSSID, or the second moment is the moment when the access point last receives a beacon frame that triggers the access point to send a beacon frame carrying the first BSSID.

[0039] In one implementation, the signal strength of the most recently received beacon frame carrying the first BSSID is lower than a preset threshold.

[0040] In one implementation, the preset duration is less than a beacon transmission period, and the preset duration is greater than a total duration of a channel occupied by at least one access point in the WLAN system for transmitting a beacon frame.

[0041] In a fourth aspect, the present application provides a beacon frame sending method, which is performed by a second communication device. The second communication device may be a terminal, or the second communication device may be a component for implementing the functions of the terminal. For example, the second communication device may be a unit / module, a circuit or a chip inside the terminal. The method provided in the fourth aspect is described below by taking the second communication device as the terminal itself as an example. Of course, the method provided in the third aspect may also be implemented by a unit / module, a circuit or a chip inside the terminal. The terminal is a terminal in the WLAN system of the second aspect, and the beneficial effects can be referred to the description of the second aspect and will not be repeated here.

[0042] The method includes: a terminal receives a third beacon frame, where the third beacon frame is obtained according to a first beacon frame and the second beacon frame, where the first beacon frame includes a first BSSID, and the second beacon frame includes the first BSSID.

[0043] In one implementation, the third beacon frame is obtained according to the first beacon frame and the second beacon frame, including: a signal carrying the third beacon frame is a superposition of a signal carrying the first beacon frame and a signal carrying the second beacon frame.

[0044] In one implementation, the second beacon frame and the first beacon frame each include the same content, the same scrambling code, and the same MCS.

[0045] In one implementation, the sending of the first beacon frame is triggered by a timing synchronization frame, and the sending of the second beacon frame is triggered by a timing synchronization frame.

[0046] In one implementation, the timing synchronization frame includes a timestamp, and the timestamp instructs an access point receiving the timing synchronization frame to add the timestamp to a beacon frame to be transmitted.

[0047] In one implementation, the sending time of the first beacon frame is a first time, the sending time of the second beacon frame is a second time, and the first time and the second time are the same.

[0048] In one implementation, the interval between the first time and the second time is smaller than a preset interval.

[0049] In one implementation, the preset interval is less than or equal to the GI, and the time synchronization accuracy between the first access point that sends the first beacon frame and the second access point that sends the second beacon frame is higher than the GI.

[0050] In a fifth aspect, the present application provides a beacon frame sending method, which is performed by a third communication device. The third communication device may be an access point, or the third communication device may be a component for implementing the functions of an access point. For example, the third communication device may be a unit / module, a circuit or a chip inside the access point. The method provided in the fifth aspect is described below by taking the third communication device as the access point itself as an example. Of course, the method provided in the third aspect may also be implemented by a unit / module, a circuit or a chip inside the access point. The access point is an access point in the WLAN system of the second aspect, and the beneficial effects may be referred to the description of the second aspect and will not be repeated here.

[0051] The method includes: an access point receiving a timing synchronization frame; in response to receiving the timing synchronization frame, the access point sending a first beacon frame, the first beacon frame including a first BSSID.

[0052] In one implementation, the timing synchronization frame includes a timestamp, which instructs an access point receiving the timing synchronization frame to add the timestamp to a beacon frame to be transmitted.

[0053] In a sixth aspect, the present application provides a communication device, which has the function of implementing the behavior of the first access point or the second access point or the terminal device mentioned in the first aspect or the second aspect. The beneficial effects can be referred to the relevant description of the first aspect to the second aspect and will not be repeated here. The function can be implemented by hardware or by hardware executing corresponding software. The hardware or software includes one or more units corresponding to the above functions.

[0054] In one possible design, the communication device includes corresponding means or modules for executing the method of any aspect from the third aspect to the fifth aspect. For example, the communication device includes a processing unit and / or a transceiver unit. These unit modules can perform the corresponding functions of the first access point, the second access point or the terminal device in the method example of the third aspect, the fourth aspect or the fifth aspect. Please refer to the detailed description in the method example for details, which will not be repeated here. For example, the communication device may be the first access point or the second access point or the terminal device in the first aspect or the second aspect. For another example, the communication device may be a device that can support the access point or the terminal device to implement the functions required by the WLAN system provided by the first aspect or the second aspect, for example, the communication device may be a chip or a chip system in the access point or the terminal device. Among them, the processing unit is also called a processing module or a processor; the transceiver unit is also called a transceiver module or a transceiver. The processing unit can be used to generate a beacon frame. The transceiver unit can realize the sending function and the receiving function (for example, used to send a beacon frame or receive a beacon frame). When the transceiver unit realizes the sending function, it can be called a sending unit (sometimes also called a sending module). When the transceiver unit realizes the receiving function, it can be called a receiving unit (sometimes also called a receiving module). The sending unit and the receiving unit can be the same functional unit, which is called a transceiver unit, and the functional unit can realize the sending function and the receiving function; or, the sending unit and the receiving unit can be different functional units, and the transceiver unit is a general term for these functional units. These units (modules) can perform the corresponding functions in the method examples of any aspect from the third aspect to the fifth aspect above. Please refer to the detailed description in the method example for details, which will not be repeated here.

[0055] In a seventh aspect, the present application provides a communication device, which may be the first access point (or the second access point or the terminal device) in the above-mentioned embodiment, or a chip or a chip system arranged in the first access point (or the second access point or the terminal device). The beneficial effects can be found in the description of the first aspect or the second aspect and are not repeated here. The communication device includes a communication interface and a processor, and the processor is used to execute the method performed by the first access point, the second access point or the terminal device in the above-mentioned method embodiment. For example, the communication device may be the first access point, the second access point or the terminal device, and the communication device may also be a functional module in the first access point, the second access point or the terminal device, such as a processing chip and a radio frequency chip.

[0056] Optionally, the communication device also includes a power supply circuit and a memory. The power supply circuit is used to power the processor. The present application does not limit the specific type of the processor. For example, the processor may be a central processing unit (CPU) or other specific integrated circuits. For another example, the processor may be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components.

[0057] Computer program instructions are stored in the memory, and the processor is coupled to the memory. The processor can call the computer execution instructions stored in the memory to execute the method executed by the first access point, the second access point or the terminal device in any aspect of the third to fifth aspects and each implementation method.

[0058] In an eighth aspect, the present application provides a communication device, which may be the communication device in the sixth aspect or the seventh aspect of the above-mentioned embodiment, or a chip or chip system arranged in the communication device in the sixth aspect or the seventh aspect. The communication device includes a processor and a memory, the memory is used to store computer programs or instructions or data, and the processor is coupled to the memory. When the processor reads the computer program or instructions or data, the communication device executes the method executed by the first access point, the second access point or the terminal device in the above-mentioned method embodiment.

[0059] In one implementation, the memory is located outside the communication device.

[0060] In one implementation, the memory is located within the communication device.

[0061] In one implementation, the processor and the memory are integrated together.

[0062] In a ninth aspect, the present application provides a chip system, which includes a processor and may also include a communication interface for implementing the method described in any aspect from the third aspect to the fifth aspect.

[0063] In one implementation, the chip system also includes a memory. The memory is used to store a computer program (also referred to as code, or instruction). The processor is used to call and run the computer program from the memory, so that the device equipped with the chip system executes the method in the third aspect and any one of its implementations, or the device equipped with the chip system executes the method in the fourth aspect and any one of its implementations, or the device equipped with the chip system executes the method in the fifth aspect and any one of its implementations. The chip system can be composed of chips, or it can include chips and other discrete devices.

[0064] In a tenth aspect, the present application provides a communication device, which includes an input / output interface and a logic circuit. The input / output interface is used to input and / or output information. The input / output interface can be an interface circuit, an output circuit, an input circuit, a pin or a related circuit, etc. The logic circuit is used to execute the method described in any aspect of the third aspect to the fifth aspect.

[0065] In the specific implementation process, the above-mentioned communication device can be a chip, the input circuit can be an input pin, the output circuit can be an output pin, and the logic circuit can be a transistor, a gate circuit, a trigger, and various logic circuits. The input signal received by the input circuit can be, for example, but not limited to, received and input by a receiver, and the signal output by the output circuit can be, for example, but not limited to, output to a transmitter and transmitted by the transmitter, and the input circuit and the output circuit can be the same circuit, which is used as an input circuit and an output circuit at different times. This application does not limit the specific implementation of the input and output interface and the logic circuit.

[0066] In one implementation, when the communication device is a wireless communication device, the wireless communication device may be a terminal device such as a mobile phone. The interface circuit may be a radio frequency processing chip in the wireless communication device, and the processing circuit may be a baseband processing chip in the wireless communication device. Alternatively, the wireless communication device may be an access point such as a router. The interface circuit may be a radio frequency processing chip in the wireless communication device, and the processing circuit may be a processing chip in the wireless communication device.

[0067] In an eleventh aspect, the present application provides a computer-readable storage medium, which is used to store a computer program or instruction. When the computer program or instruction is executed, the access point executes the method executed by the first access point in the third aspect and any one of its implementations, or the terminal device executes the method executed by the terminal device in the fourth aspect and any one of its implementations, or the access point executes the method executed by the first access point in the fifth aspect and any one of its implementations.

[0068] In the twelfth aspect, the present application also provides a computer program product comprising instructions, which, when executed on a computer, enables the method described in the third aspect and any one of its implementations to be implemented, or enables the method described in the fourth aspect and any one of its implementations to be implemented, or enables the method described in the fifth aspect and any one of its implementations to be implemented.

[0069] The beneficial effects of the sixth to twelfth aspects and their implementations can refer to the description of the beneficial effects of any aspect from the first to fifth aspects and any implementation of them. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] Figure 1 A schematic diagram of the architecture of a WLAN system provided in an embodiment of the present application;

[0071] Figure 2 A schematic diagram of the principle of the BSSID following solution provided in the embodiment of the present application;

[0072] Figure 3 A schematic diagram of the principle of the BSSID same solution provided in the embodiment of the present application;

[0073] Figure 4 A flow chart of a communication method 400 provided in an embodiment of the present application;

[0074] Figure 5 A schematic diagram of a communication method 400 provided in an embodiment of the present application for filtering beacon frames with weak signal strength;

[0075] Figure 6 A schematic diagram of the principle of packet loss occurring in a terminal provided in an embodiment of the present application;

[0076] Fig. 7A A schematic diagram of the principle of the access point determining whether the scheduled beacon sending time has been reached according to an embodiment of the present application;

[0077] Figure 7B A schematic diagram of the principle of an access point determining whether to send a beacon at a scheduled beacon sending time provided in an embodiment of the present application;

[0078] Figure 8 A schematic diagram of two APs sending beacon frames to a terminal via different transmission paths provided in an embodiment of the present application;

[0079] Fig. 9 A schematic diagram of a communication method 900 provided in an embodiment of the present application;

[0080] Fig.10 A schematic diagram of the structure of a communication device provided in an embodiment of the present application;

[0081] Fig.11Another structural schematic diagram of a communication device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0082] The embodiment of the present application provides a WLAN system, which includes multiple access points and at least one terminal. The WLAN system can reduce the number of times the terminal roaming is triggered, thereby reducing service transmission delay and reducing the impact on service transmission.

[0083] The embodiments of the present application can be applicable to WLAN scenarios, can be applicable to IEEE 802.11 system standards (such as 802.11ax standards), and can also be applicable to the next generation of 802.11ax standards, such as 802.11be standards (Wi-Fi 7 or extremely high throughput (EHT)), 802.11ad, 802.11ay, 802.11bf. The embodiments of the present application can also be applied to WLAN systems such as the Internet of Things (IoT) network or the Vehicle to X (V2X) network. Of course, the embodiments of the present application can also be applied to other possible communication systems, such as long term evolution (LTE) systems, new radio (NR) systems, and future cellular communication systems, such as the sixth generation mobile communication technology (6G), etc.

[0084] For example, see Figure 1 , Figure 1 A schematic diagram of the architecture of a WLAN system provided in an embodiment of the present application. Figure 1 Take the WLAN system including N APs (which may be referred to as access points), two terminals and an access controller (AC) as an example, where N is an integer greater than or equal to 2. N APs, namely the first access point to the Nth access point. Two terminals, namely the first terminal and the second terminal. Among them, the AC has control functions such as configuration management, access, and scheduling of each access point. The AC can be an independent device, or a software program of at least one of the N APs, or a software program in the cloud. Figure 1 For example, AC is an independent device. AC can be connected to N APs via wired or wireless connections. Figure 1The number of APs and terminals in the example is only an example, and can be more or less. The embodiments of the present application are also applicable to communication between APs, for example, each AP can communicate with each other through a distributed system (DS). Through the DS, the AP can communicate with the terminals associated with it and / or the unassociated terminals. The embodiments of the present application are also applicable to communication between terminals.

[0085] AP is a device deployed in a wireless communication network to provide wireless communication functions for terminals associated with it. AP can be an access point for terminals (such as mobile phones) to enter a wired (or wireless) network. It is mainly deployed in homes, buildings, and campuses. The typical coverage radius of AP is tens of meters to hundreds of meters. Of course, AP can also be deployed outdoors. AP is equivalent to a bridge connecting wired and wireless networks. Its main function is to connect various wireless network clients to the wireless network, and then connect the wireless network to the Internet.

[0086] The AP involved in the embodiments of the present application may be an access point applicable to current or future wireless fidelity (Wi-Fi) standards. For example, the AP involved in the embodiments of the present application may be an AP applicable to the IEEE802.11 system standard. For example, the AP may be a device supporting the 802.11be standard, or it may be a device supporting multiple WLAN standards of the 802.11 family such as 802.11ay, 802.11ad, 802.11ax, and 802.11be next generation. For example, the AP may be a communication device such as a base station, a router, a gateway, a repeater, a communication server, a switch or a bridge, wherein the base station may include various forms of macro base stations, micro base stations, relay stations, etc. For another example, the AP may be a terminal device (such as a mobile phone) or a network device (such as a router) with a Wi-Fi chip.

[0087] The terminal may be a terminal that supports the Wi-Fi standard. For example, the terminal may be a wireless communication chip, a wireless sensor, or a wireless communication terminal, etc., and may also be referred to as a user. For example, the terminal may be a station (STA), a mobile phone, a tablet computer, a set-top box, a smart TV, a smart wearable device, a vehicle-mounted communication device, and a computer, etc. that support Wi-Fi communication functions. In one implementation, the terminal supports the 802.11be standard; alternatively, the terminal may also support a variety of WLAN standards of the 802.11 family, such as 802.11ay, 802.11ad, 802.11ax, and the next generation of 802.11be. In an embodiment of the present application, the AP and the terminal may be devices used in the Internet of Vehicles, IoT nodes, sensors, etc. in the IoT, smart cameras in smart homes, smart remote controls, smart water meters and electricity meters, and sensors in smart cities, etc.

[0088] As the terminal moves, it may move from the coverage of one AP to the coverage of another AP. In order to ensure the service continuity and communication quality of the terminal, the terminal will be triggered to roam. Triggering terminal roaming means triggering the terminal to disconnect from the associated access point and trigger the terminal to establish an association with another access point. Figure 1 For example, taking the second terminal as an example, the second terminal is initially associated with the first access point. As the second terminal moves, the second terminal moves from the coverage area of ​​the first access point to the coverage area of ​​the second access point ( Figure 1 Indicated by arrows). At this time, the roaming process of the second terminal is triggered, that is, the second terminal is triggered to release the association with the first access point and establish an association with the second access point. Figure 1 The second terminal and the first access point are not associated with each other as indicated by a dotted line, and the second terminal and the second access point are associated with each other as indicated by a solid line. When the terminal is roaming, the transmission of the service will be interrupted. In possible scenarios, the service transmission delay requirement is high. If the terminal frequently triggers roaming, the service transmission delay will be too large, and the connection with the network may even be disconnected, resulting in packet loss, which seriously affects the transmission of the service.

[0089] Therefore, in WLAN co-frequency networking, in order to avoid the terminal triggering roaming, it is expected that the terminal will regard different APs as the same AP. In this way, when the terminal moves from the coverage of one AP to the coverage of another AP, the terminal believes that it is always in the coverage of the same AP, so the roaming process will not be triggered. The terminal determines the existence of the AP based on the beacon frame sent by the AP. The beacon frame includes the ID of the BSS of the wireless network where the AP is located. The AP sends a beacon frame, and the terminal receives the beacon frame and obtains the BSSID carried by the beacon frame, thereby determining the AP indicated by the BSSID. In WLAN co-frequency networking, the service set identifier (SSID) used by each AP is the same.

[0090] In one implementation, each terminal is assigned / configured with a unique BSSID. For the same terminal, the beacon frames sent to the terminal by different APs carry the same BSSID. When the terminal moves from the coverage of one AP to the coverage of another AP, the BSSID carried in the beacon frames received by the terminal remains unchanged. Therefore, the terminal believes that it is always in the coverage of one AP and does not trigger the roaming process. This method can be called a BSSID following solution.

[0091] In the BSSID following scheme, the terminal can broadcast a probe request message to actively scan the surrounding wireless networks. The probe request message may include the terminal's identifier; the AP that receives the probe request message may feed back a probe response message to the terminal, and the probe response message carries the BSSID. Initially, for the same terminal, different APs respond to the probe request message of the terminal, and the BSSIDs carried in the probe response messages sent are different. For example, AP1 responds to the probe request message of terminal 1, and the BSSID carried in the probe response message sent is BSSID1; AP2 responds to the probe request message of terminal 1, and the BSSID carried in the probe response message sent is BSSID2. The terminal receives the probe response message and can determine that the AP corresponding to the probe response message exists. The terminal can select a suitable AP from the determined APs for link authentication and association. There are many ways for the terminal to select an AP, and the specific way the terminal uses to select an AP is not limited. For example, the terminal may give priority to an AP with a stronger signal strength; for another example, the terminal may give priority to an AP of a 5G channel. After the terminal successfully associates with the AP, the AP determines the BSSID corresponding to the terminal through the destination address of the association request sent by the terminal. This BSSID is the only BSSID of the terminal and is no longer used to respond to the detection requests of other terminals until the terminal is disassociated.

[0092] Considering that the AP selected by the terminal itself may not be the best, the AC can also select a better AP for the terminal later. For example, the AC can periodically select the best access AP for the terminal based on the signal strength. If the AC finds a better new AP for the terminal, the AC can send the terminal information to the new AP, create a virtual AP (virtual access point, VAP) on the new AP to send the BSSID beacon frame corresponding to the terminal to provide services for the terminal, and delete the terminal information on the old AP so that the old AP will no longer respond to the terminal. After the AC selects a new AP for the terminal, it will create a VAP on the new AP to send the BSSID beacon frame corresponding to the terminal. Therefore, the beacon frames sent by different APs to the same terminal all carry the BSSID assigned to the terminal. For the terminal, it is considered to be always within the coverage of one AP and will not trigger the roaming process.

[0093] For easier understanding, see Figure 2 , Figure 2 The figure is a schematic diagram showing the principle of the BSSID following solution. Figure 2In the example, the BSSID assigned to terminal 1 is BSSID1, and the BSSID assigned to terminal 2 is BSSID2, and terminal 2 moves from the coverage of AP1 to the coverage of AP2. Initially, terminal 2 is located in the coverage of AP1, and the beacon frame sent by AP1 to terminal 2 carries BSSID2. When terminal 2 moves to the coverage of AP2, the BSSID carried in the beacon frame sent by AP2 to the terminal is BSSID2, and the beacon frame received by terminal 2 from AP2 also carries BSSID2. From the perspective of terminal 2, the BSSID included in the beacon frame received by terminal 2 has not changed, so there is no need to trigger the roaming process.

[0094] However, one AP can be accessed by multiple terminals. Accordingly, the BSSID following solution requires the AP to maintain the BSSID corresponding to each terminal. When the number of terminals is large, the AP needs to maintain more BSSIDs and sends more beacon frames, which will occupy more air interface resources and affect the throughput performance of the WLAN network.

[0095] In another implementation, the BSSID carried by the beacon frames sent by different APs is the same. In this case, the BSSID carried by the beacon frames received by any terminal from different APs remains unchanged, so there is no need to trigger the roaming process. This method is also called the same BSSID solution or the same BSSID solution.

[0096] For easier understanding, see Figure 3 , Figure 3 The figure is a schematic diagram showing the principle of the BSSID same solution. Figure 3 Take the example that the beacon frames sent by AP1 and AP2 both include BSSID1. AP1 and AP2 will broadcast beacon frames periodically. Take terminal 1 and terminal 2 as an example, assuming that terminal 1 and terminal 2 are initially located in the coverage of AP1. The beacon frame sent by AP1 to terminal 1 carries BSSID1. When terminal 1 moves to the coverage of AP2, the beacon frame received by terminal 1 from AP2 also carries BSSID1. From the perspective of terminal 1, the BSSID included in the beacon frame received by terminal 1 has not changed, so there is no need to trigger the roaming process. Similarly, the beacon frame sent by AP1 to terminal 2 carries BSSID1. When terminal 2 moves to the coverage of AP2, the beacon frame received by terminal 2 from AP2 also carries BSSID1. From the perspective of terminal 2, the BSSID included in the beacon frame received by terminal 2 has not changed, so there is no need to trigger the roaming process.

[0097] In actual deployment, the distances between different APs in the WLAN system and the same terminal may be different. Accordingly, the signal strengths of beacon frames received by the terminal from different APs may also be different. If the signal strength of the beacon frame received by the terminal is weak, the terminal will think that the current network is not good and will still trigger the roaming process, which will lead to excessive service transmission delay and even packet loss, seriously affecting service transmission.

[0098] In order to solve the above technical problems, a communication method of an embodiment of the present application is provided. The communication method provided by the embodiment of the present application can make the signal strength of the beacon frame received by the terminal stronger, so as to reduce the triggering of the terminal roaming process, thereby reducing the service transmission delay and reducing the packet loss.

[0099] The embodiments of the present application provide a variety of communication methods. First, the first communication method provided by the embodiments of the present application is introduced. The first communication method can enable the terminal to filter out beacon frames with weak signal strength or can enable the terminal to not receive beacon frames with weak signal strength, so that the signal strength of the beacon frames received by the terminal is strong, so as to reduce the triggering of the roaming process.

[0100] Filtering out the beacon frame can also be understood as not being able to receive the beacon frame or demodulate the content contained in the beacon frame. Demodulation refers to the process of recovering information from a modulated signal that carries information. The modulated signal carrying the beacon frame received by the terminal needs to be demodulated to obtain the content included in the beacon frame. The power of the signal received by the terminal receiver needs to meet certain conditions before the terminal can demodulate the content included in the received beacon frame. The minimum signal receiving power that the receiver can correctly demodulate the content included in the received signal can also be considered as the minimum signal receiving power of the antenna port required for the normal operation of the receiver. The minimum signal receiving power is the minimum signal strength, also known as receiving sensitivity.

[0101] The receiving sensitivity of the receiver is related to the MCS of the signal and the bandwidth of the signal. Generally, the transmission rate of a lower-order MCS is lower and the spectrum efficiency is lower, but the anti-interference performance is good; the transmission rate of a higher-order MCS is higher and the spectrum efficiency is higher, but the adaptability to noise and interference is poor. The higher the modulation order of the signal, the higher the signal-to-noise ratio required to demodulate the signal. If the strength of the signal received by the receiver is weak (for example, the power of the signal is less than the receiving sensitivity), then the receiver cannot demodulate the content from the signal with weak signal strength. For this reason, in order to enable the terminal to demodulate the received signal, special management frames are usually sent in a lower modulation order. For example, the beacon frame plays the role of timing and announcing the existence of the network for the terminal, and the beacon frame has no confirmation retransmission mechanism. Therefore, it is more important whether the terminal can receive the beacon frame. In order to enable the terminal to receive the beacon frame, the beacon frame is usually sent using a lower-order MCS.

[0102] However, in the first communication method, each AP may use a higher modulation order to send a beacon frame. In this way, if the signal strength of the beacon frame from the AP is weak, the terminal cannot demodulate the signal carrying the beacon frame or the terminal cannot receive the beacon frame from the AP, and the roaming process will naturally not be triggered. In the embodiment of the present application, the AP sending the beacon frame includes the AP broadcasting the beacon frame.

[0103] In one implementation, the modulation order used by each AP is determined according to a modulation order threshold. For example, the modulation order used by each AP is higher than or equal to the modulation order threshold.

[0104] In one implementation, each AP obtains a modulation order threshold, for example, the AP receives the modulation order threshold sent by the AC, or the order threshold is configured in advance for each AP. For example, the modulation order threshold is 64-QAM, and accordingly, each AP can use 64-QAM to modulate the beacon frame signal, or use a modulation order higher than 64-QAM (for example, 256-QAM) to modulate the beacon frame signal.

[0105] In one implementation, the modulation order threshold may be determined according to a signal strength threshold. For example, the modulation order threshold is higher than or equal to the modulation order corresponding to the signal strength threshold. The modulation order corresponding to the signal strength threshold is: when the signal is modulated using the modulation order, if the signal strength of the signal received by the receiving end is greater than or equal to the signal strength threshold, the receiving end may demodulate the received signal.

[0106] For example, a mapping relationship between multiple signal strength thresholds and modulation order thresholds can be (pre-)configured. When any AP sends a beacon frame, the signal strength threshold can be determined, and the modulation order threshold can be determined based on the signal strength threshold and the mapping relationship, and then the modulation order to be used can be determined based on the modulation order threshold.

[0107] For the WLAN system, the signal strength threshold can be determined based on the minimum signal strength required for the terminal to maintain a connection (i.e., the signal strength threshold for the terminal to trigger roaming). For example, the signal strength threshold is greater than or equal to the signal strength threshold for the terminal to trigger roaming. It is understandable that for any terminal, when the signal strength of the received beacon frame is lower than the threshold for the terminal to trigger roaming, the terminal will scan for roaming candidate BSSIDs. When the modulation order used by the AP is higher than or equal to the modulation order threshold corresponding to the signal strength threshold for the terminal to trigger roaming, if the signal strength of the beacon frame is lower than the signal strength threshold for the terminal to trigger roaming, the terminal cannot demodulate the received beacon frame and will not trigger roaming due to the weak signal strength of the beacon frame.

[0108] The embodiments of the present application do not limit how to determine the signal strength threshold for triggering roaming of a terminal. For example, the signal strength threshold can be determined by counting the signal strength thresholds for triggering roaming of multiple terminals. For example, the signal strength threshold can be a statistical value of the signal strength thresholds for triggering roaming of these multiple terminals, such as a maximum value, an average value, or a quantile value. These multiple terminals can be all or part of the terminals in the WLAN system. The part of the terminals can be terminals of a specified brand, terminals of a specified model, or certain specified terminals (for example, terminals used by VIP users).

[0109] The embodiments of the present application do not limit the manner in which the signal strength for terminal-triggered roaming is obtained. The AP may request the terminal to obtain the signal strength for terminal-triggered roaming. For example, the AP sends a request message to the terminal to request the signal strength for terminal-triggered roaming; the terminal sends the signal strength for terminal-triggered roaming to the AP in response to the request message. For another example, the AP may calculate the signal strength for terminal-triggered roaming based on the historical signal strength for terminal-triggered roaming, or the AP may obtain the signal strength for terminal-triggered roaming through testing. For another example, the signal strength for terminal-triggered roaming may be public (for example, the signal strength for terminal-triggered roaming is public on the website of the terminal manufacturer), and the AP (or, through the AC or other management / control systems) may obtain the signal strength for terminal-triggered roaming from the website.

[0110] Optionally, the mapping relationship between the signal strength threshold for triggering roaming of each terminal and the modulation order threshold can be (pre-)configured. When any AP sends a beacon frame, the signal strength threshold for triggering roaming of at least one terminal can be obtained, and the modulation order threshold can be determined according to the signal strength threshold for triggering roaming of at least one terminal and the mapping relationship, and then the modulation order to be used can be determined according to the modulation order threshold corresponding to at least one terminal. For the convenience of description, "the modulation order threshold corresponding to the signal strength threshold for terminal triggering roaming" can be referred to as "the modulation order threshold corresponding to terminal triggering roaming". When the AP sends a beacon frame, the maximum modulation order threshold among the modulation order thresholds corresponding to at least one terminal triggering roaming can be used as the minimum modulation order to be used by the AP. Alternatively, the modulation order used by the AP is higher than or equal to the maximum modulation order threshold among the modulation order thresholds corresponding to at least one terminal triggering roaming.

[0111] Alternatively, the mapping relationship between the receiving sensitivity (or minimum signal strength) and the modulation order can be (pre-)configured, and when each AP sends a beacon frame, the modulation order to be used can be determined based on the signal strength threshold for the terminal to trigger roaming and the mapping relationship. For example, the receiving sensitivity corresponding to the modulation order used by the AP needs to be greater than the signal strength threshold for the terminal to trigger roaming.

[0112] For example, please refer to Table 1, which shows a mapping relationship between receiving sensitivity and modulation order. Table 1 shows the mapping relationship between receiving sensitivity and modulation order when the AP uses dual carrier modulation (DCM) technology. It should be noted that the mapping relationship between receiving sensitivity and modulation order in Table 1 is only an example, and the receiving sensitivity corresponding to the same modulation order may be other values. For example, in Table 1, when DCM is not used, the receiving sensitivity corresponding to 16-QAM may also be other possible values ​​besides -74dBm and -70dBm.

[0113] Table 1

[0114]

[0115]

[0116] If the signal strength threshold for the terminal to trigger roaming is -70dBm, then a signal with a signal strength lower than -70dBm (for example, -74dBm) is considered to be a signal with a weak signal strength. According to Table 1, when the modulation order available to the AP is less than or equal to 16-QAM, the terminal can demodulate a beacon frame with a signal strength lower than -70dBm. When the receiving sensitivity corresponding to the modulation order adopted by the AP is greater than or equal to the signal strength threshold for the terminal to trigger roaming (for example, the modulation order used by the AP is greater than or equal to 64-QAM), the terminal cannot demodulate a beacon frame with a signal strength lower than -70dBm. Therefore, even if the terminal receives a beacon frame with a weak signal strength, when the signal strength of the received beacon frame is lower than -70dBm, the terminal cannot demodulate the beacon frame / cannot receive the beacon frame, and naturally, the terminal will not trigger roaming.

[0117] Since the channel bandwidths in which the APs work are different, the requirements for receiving sensitivity may also be different, and the requirements for modulation orders may also be different. From this perspective, the modulation order used by the AP can also be determined based on the channel bandwidth in which the AP works. The mapping relationship between receiving sensitivity, channel bandwidth, and modulation order can be (pre-)configured. When any AP sends a beacon frame, the modulation order to be used can be determined based on the channel bandwidth in which the AP works and the mapping relationship. Alternatively, the AP can select the mapping relationship between receiving sensitivity and modulation order based on the working channel bandwidth. When sending a beacon frame, the modulation order to be used can be determined based on the mapping relationship and the signal strength threshold for the terminal to trigger roaming.

[0118] For example, see Table 2, which shows a mapping relationship between receiving sensitivity, modulation order, and channel bandwidth. Table 2 shows a mapping relationship between receiving sensitivity, channel bandwidth, and modulation order when the AP uses the DCM technology.

[0119] Table 2

[0120]

[0121] Assuming that the signal strength threshold for the terminal to trigger roaming is -70dBm, when the channel bandwidth of the beacon frame is 20MHz, according to Table 2, when the modulation order used by the AP is less than or equal to 16-QAM, the terminal can demodulate the beacon frame with a signal strength lower than -70dBm. When the receiving sensitivity corresponding to the modulation order used by the AP is greater than or equal to the signal strength threshold for the terminal to trigger roaming (for example, the modulation order used by the AP is greater than or equal to 64-QAM), the terminal cannot demodulate the beacon frame with a signal strength lower than -70dBm. Therefore, even if the terminal receives a beacon frame with a weak signal strength (for example, the signal strength of the beacon frame is lower than -70dBm), the terminal cannot demodulate the beacon frame / cannot receive the beacon frame, and naturally, the terminal will not trigger roaming. Similarly, assuming that the signal strength threshold for the terminal to trigger roaming is -64dBm, when the channel bandwidth of the beacon frame is 40MHz, and the modulation order used by the AP is greater than or equal to 256-QAM, the terminal cannot demodulate the beacon frame with a signal strength lower than -64dBm. Therefore, even if the terminal receives a beacon frame with a weak signal strength (for example, the signal strength of the beacon frame is lower than -64dBm), the terminal cannot demodulate the beacon frame / cannot receive the beacon frame, and naturally, the terminal will not trigger roaming.

[0122] It should be noted that the mapping relationship between the receiving sensitivity, channel bandwidth and modulation order in Table 2 is only an example, and the receiving sensitivity corresponding to the same modulation order may be other values. For example, in Table 2, at 20MHz, the receiving sensitivity corresponding to 16-QAM may also be other possible values ​​besides -74dBm and -70dBm.

[0123] The modulation orders used by different APs to send beacon frames can be the same or different, as long as the terminals cannot demodulate or receive beacon frames with weak signal strength. Taking AP1 and AP2 as examples, the modulation order used by AP1 can be 64-QAM, and the modulation order used by AP2 can also be 64-QAM; for another example, the modulation order used by AP1 can be 64-QAM, and the modulation order used by AP2 can also be 256-QAM.

[0124] The communication method provided in the embodiments of the present application is described in detail below with reference to the accompanying drawings.

[0125] It should be noted that the communication method involved in the embodiment of the present application involves the interaction between multiple access points and terminals, and may also involve the interaction between access points. In some scenarios, the roles of each access point are the same, and the steps performed by each access point are the same. In some scenarios, the roles of different access points are different, for example, some access points are master access points, and some access points are slave access points. In this case, the steps performed by each slave access point are the same. The master access point can be selected by the AC from multiple access points. For example, the AC can randomly select an access point from multiple access points as the master access point, which is relatively simple. For another example, the AC can select an access point with a relatively central position among multiple access points as the master access point, which can reduce the number of hops or relays between the master access point and the slave access point at the edge of the network. The number of hops or relays is the number of access points that are traversed to forward the information of one access point to another access point. For example, if the distance between access point A and access point B is far, when access point A sends a beacon to access point B, the beacon can be forwarded (relayed) to access point B through other access points. The number of other access points between access point A and access point B is the number of hops or relays. After the AC selects the master access point, it sends configuration information to each slave access point. The configuration information may indicate which access point is the master access point and which access point or points are slave access points.

[0126] The master access point can determine the scheduled beacon transmission time according to its own clock, and send a beacon frame at the scheduled beacon transmission time. For example, when the ratio of the master access point's own clock to the beacon transmission period is an integer, the scheduled beacon transmission time is reached. Taking the beacon transmission period of 102400us as an example, when the ratio of the master access point's own clock to 102400us is an integer, the scheduled beacon transmission time of the master access point is reached. The slave access point can decide whether to send a beacon frame and how to send a beacon frame based on the received beacon frame (which will be described in detail below). The beacon transmission period can be configured by the AC. For example, the configuration information sent by the AC to each access point includes the beacon transmission period. The beacon transmission period can also be predefined. The embodiment of the present application does not limit the length of the beacon transmission period. For example, the beacon transmission period can be 100TUs, 1TU=1024us. Alternatively, the beacon transmission period can also be 200TUs, 400TUs, etc.

[0127] In the embodiment of the present application, the steps performed by the access point may be implemented by the access point itself, or by a component in the access point (such as a chip, or other processing units or processor modules). For example, the access point may be Figure 1 The first access point or the second access point in the Figure 1The steps performed by the terminal may be implemented by the terminal itself, or by a component (such as a chip, a processing unit, or a processor module) in the terminal.

[0128] First, the first communication method provided by the embodiment of the present application is introduced.

[0129] See also Figure 4 , is a flow chart of a communication method 400 provided in an embodiment of the present application. The communication method 400 is the first communication method. Figure 4 Taking the communication method 400 executed by the first access point, the second access point, the third access point and the terminal as an example, the communication method 400 is introduced from the perspective of the interaction between the first access point (AP1), the second access point (AP2) and the third access point (AP3) and the terminal. It should be understood that the communication method 400 can also be implemented by other devices, such as a chip or a communication device with communication functions. Figure 4 As shown, the process of the first communication method 400 includes the following steps.

[0130] S401. A first access point sends a first beacon frame, where the first beacon frame includes a first BSSID and uses a first modulation order.

[0131] During the beacon transmission cycle, when the scheduled beacon frame transmission time is reached, the first access point can transmit the first beacon frame. The first beacon frame carries the first BSSID to inform the terminal of the existence of the first access point. The scheduled beacon frame transmission time can be determined based on the beacon transmission cycle and the first access point's own clock. Taking a beacon transmission cycle of 102400us as an example, when the ratio of the first access point's own clock to 102400us is an integer, the scheduled beacon transmission time is reached. In one implementation, the first access point may transmit the first beacon frame triggered by a timer, and the timing duration of the timer is, for example, 102400us.

[0132] The first access point may modulate the first beacon frame using the first modulation order. As mentioned above, in order to prevent the terminal from receiving beacon frames with weak signal strength to reduce the triggering of roaming, the first access point may determine the modulation order to be used according to the modulation order threshold corresponding to at least one terminal triggering roaming. For the determination of the modulation order, please refer to the above-mentioned related content, which will not be repeated here.

[0133] S402: The second access point sends a second beacon frame, where the second beacon frame includes the first BSSID and uses a second modulation order.

[0134] Similar to the first access point, the second access point can also send a beacon frame. The second beacon frame also carries the first BSSID. Taking into account that the distances from each access point to the terminal are different in the WLAN system, the signal strengths of the beacon frames sent by each access point to the terminal may also be different. In order to enable the terminal to filter out beacon frames with weaker signal strength and reduce the number of times the roaming process is triggered, the second beacon frame can use a higher modulation order. For example, the second beacon frame can use a second modulation order. The way the second access point determines the second modulation order is the same as the way the first access point determines the first modulation order, and will not be repeated here.

[0135] The second modulation order may be the same as the first modulation order, for example, the first access point and the second access point may select a modulation order that is one order higher than the modulation order corresponding to the signal strength for triggering roaming of the terminal. Alternatively, the second modulation order may be different from the first modulation order, for example, the first access point and the second access point may randomly select a modulation order from the modulation orders that are higher than the modulation order corresponding to the signal strength for triggering roaming of the terminal.

[0136] S403: The third access point sends a third beacon frame.

[0137] Similar to the second access point, the remaining access points in the WLAN system (eg, the third access point) can also send beacon frames (eg, the third beacon frame). The third beacon frame carries the first BSSID and uses a higher modulation order, for example, the third beacon frame uses 64-QAM.

[0138] It is understandable that other access points like the second access point or the third access point will also send beacon frames, and the sent beacon frames all carry the first BSSID and use a higher modulation order, so that the terminal can filter out beacon frames with weaker signal strength.

[0139] For example, see Figure 5 , Figure 5 A schematic diagram of a WLAN system. Figure 5 Take the first WLAN system including AP1-AP5 as an example. AP1-AP5 send beacon frames respectively, and the beacon frames sent by AP1-AP5 all carry the first BSSID and use a higher modulation order. Therefore, the terminal will not receive the beacon frames with weaker signals in AP1-AP5. Figure 5 As shown, AP2 and AP5 are far away from the terminal, and the signal strength of the beacon frames from AP2 and AP5 to the terminal is weak. Although AP2 and AP5 send beacon frames, the terminal only receives beacon frames sent by AP1, AP3 and AP4.

[0140] In the communication method 400 provided in the embodiment of the present application, the beacon frames sent by each access point carry the same BSSID and all use a higher modulation order, which allows the terminal to filter out beacon frames with weaker signal strength, reduce the number of times the terminal triggers the roaming process, and thus reduce service transmission delay.

[0141] The beacon frames sent by each access point may also carry a timestamp, so that other access points or terminals can know the sending time of the beacon frame according to the timestamp carried by the received beacon frame. Depending on whether the access point is a master or slave access point, the method for determining the timestamp carried by the beacon frames sent by each access point is also different.

[0142] In one scenario, the first access point, the second access point, and the third access point may be time synchronized in advance, and there is no master-slave distinction between them. In this scenario, each access point sends a beacon frame in sequence when it reaches the scheduled beacon sending time. As mentioned above, the scheduled beacon sending time can be determined based on the beacon sending period and the access point's own clock, and the beacon sending period can be configured by the AC. For example, the first access point sends the first beacon frame when it reaches the scheduled beacon sending time; the second access point sends the second beacon frame when it reaches the scheduled beacon sending time; and the third access point sends the third beacon frame when it reaches the scheduled beacon sending time. Among them, the embodiment of the present application does not limit the means used for time synchronization of each access point, as long as time synchronization can be achieved. The time synchronization accuracy of the first access point, the second access point, and the third access point can be sub-millisecond (ms) level.

[0143] The first beacon frame may carry a first timestamp, which may be a system time obtained from a system clock of the first access point. The second beacon frame may carry a second timestamp, which may be a system time obtained from a system clock of the second access point. The third beacon frame may carry a third timestamp, which may be a system time obtained from a system clock of the third access point. Alternatively, the first timestamp, the second timestamp, and the third timestamp may all be preset timestamps. The preset timestamp may be the number of beacon cycles × the beacon cycle, or the sum of the number of beacon cycles × the beacon cycle and a preset offset. The embodiment of the present application does not limit the specific value of the preset offset.

[0144] Due to the time synchronization of the first access point, the second access point and the third access point, it is possible that the scheduled beacon transmission time of different access points is the same, which will cause a conflict in the transmission of beacon frames. To this end, the order in which each access point transmits the beacon frame can be set, and multiple access points transmit the beacon frame in sequence to reduce conflicts.

[0145] The embodiments of the present application do not limit how to set the order in which each access point sends beacon frames. For example, the order in which each access point sends beacon frames can be configured by the AC. For another example, the interruption time of the timer can be set for each access point, and each access point sends a beacon frame when the timer is interrupted. The interruption time of the timer of different access points is different, so that multiple access points send beacon frames in sequence. For example, the interruption time of the timer configured for AP1 is T moment, the interruption time of the timer set for AP2 is T+first offset (offset), the interruption time of the timer set for AP2 is T+2×first offset, and so on.

[0146] In another scenario, the access points in the WLAN system are divided into master and slave, for example, the first access point is the master access point, and the second access point and the third access point are slave access points. The master access point sends a beacon frame at the scheduled beacon sending time, and the scheduled beacon sending time is an integer multiple of the beacon sending period. In this case, the timestamp carried by the beacon frame sent by the slave access point may be the sum of the timestamp carried by the received beacon frame and the processing delay. For example, the first access point sends a first beacon frame, the first beacon frame carries a first timestamp, and the second access point receives the first beacon frame from the first access point. After receiving the first beacon frame, the second access point sends a second beacon frame, the second beacon frame carries a second timestamp, and the second timestamp may be the sum of the first timestamp and the processing delay. The processing delay is the interval between the time when the second access point receives the first beacon frame and the time when the second beacon frame is sent. For example, the second access point receives the first beacon frame at time T1, the second access point frames the second beacon frame, the time at which the second beacon frame is obtained is T2, the time at which the second access point sends the second beacon frame is T3, and the processing delay is T3-T1. It can be seen that due to the processing delay, the timestamp carried by each beacon frame sent from the access point is a period of time before and after the integer multiple time point of the beacon period.

[0147] Usually, beacon frames do not have a confirmation retransmission mechanism, and the terminal may miss one or some beacon frames. In order to reduce the impact of missed beacon frames on the terminal, the terminal needs to roughly maintain synchronization with the overall BSS time. When the terminal receives a beacon frame sent by an access point, it will obtain the timestamp from the beacon frame and synchronize it to the local, so that the terminal maintains time synchronization with the access point or the terminal maintains synchronization with the timestamp sent by the beacon frame.

[0148] In order to save power consumption, some terminals usually sleep and rely on the synchronized local clock to wake up from the sleep state some time before the scheduled beacon transmission time. However, the processing delay corresponding to the slave access point that is far away from the master access point is large, and the timestamp of the beacon frame sent by the slave access point has a large deviation from the integer multiple of the beacon transmission period (i.e., the scheduled beacon transmission time). If the terminal maintains time synchronization with the slave access point, it may cause the terminal to miss the beacon frame, that is, cause the terminal to lose packets.

[0149] For easier understanding, see Figure 6 , Figure 6 The figure is a schematic diagram showing the principle of packet loss at the terminal. Figure 6 In the example, the beacon transmission period is 102400us, the scheduled beacon transmission time is an integer multiple of 102400us, and the terminal wake-up time is always before the scheduled beacon transmission time. Figure 6 As shown in (a) in the figure, the timestamp carried by the beacon frame is an integer multiple of the beacon transmission period, and the beacon transmission time is also an integer multiple of the beacon transmission period. The terminal synchronizes its own clock according to the timestamp in the beacon frame. For example, after receiving the beacon frame, the terminal synchronizes the timestamp to the local clock to wake itself up at the correct time. Therefore, the terminal can always receive the beacon frame from the access point. It can be understood that the processing delay is always accumulated from the access point. Therefore, there is a large offset between the timestamp carried by the beacon frame sent by the access point at the edge of the network and the integer multiple of the beacon transmission period. As shown in Figure 6 As shown in (b), assuming that the cumulative processing delay is 9000us, assuming that the timestamp sent by the master access point is 0us, the timestamp of the first beacon frame sent by the slave access point at the edge of the network is 0+9000us. The terminal receives this beacon frame and synchronizes the timestamp to the local start timing, that is, the terminal starts timing from 9000us, wakes itself up when the terminal is about to count to 102400us, and enters sleep after a period of wake-up time. Based on the timing of the terminal, the slave access point at the edge of the network will send a beacon again at 102400+9000us, and the terminal may enter sleep before the time when the access point sends the beacon frame (as shown in the dotted line in the figure). Therefore, the terminal cannot receive the beacon frame from the access point, that is, packet loss occurs.

[0150] In one implementation, the timestamp carried by the beacon frame sent by the slave access point and the timestamp carried by the beacon frame sent by the master access point can be the same, which is beneficial to reduce the occurrence of terminal packet loss and can reduce the processing complexity of the second access point. For example, the timestamp carried by the beacon frame sent by the slave access point and the timestamp carried by the beacon frame sent by the master access point are both preset timestamps. The preset timestamp can be the number of beacon cycles * beacon cycle, or the preset timestamp is the sum of the number of beacon cycles * beacon cycle and a preset offset. The embodiment of the present application does not limit the specific value of the preset offset.

[0151] Each slave access point can use a higher modulation order to send beacon frames so that the terminal cannot demodulate (i.e. filter out) beacon frames with weaker signal strength. The beacon frame is to let the terminal know the existence of the network. In the embodiment of the present application, the BSSID carried by the beacon frames sent by each access point is the same. If the access point sends beacon frames multiple times in a short period of time, the beacon frames sent later are unnecessary, which will increase the processing burden of the terminal. In order to reduce the number of beacon frames sent, the slave access point can determine whether to send beacon frames within a period of time.

[0152] In one implementation, the slave access point determines whether the beacon transmission time has arrived by comparing the first duration and the preset duration. The first duration is the time interval between the first moment and the second moment, the first moment is the moment when the slave access point currently receives a beacon frame carrying the BSSID, and the second moment is the moment when the slave access point last sends a beacon frame carrying the BSSID, or the second moment is the moment when the slave access point last receives a beacon frame that triggers the slave access point to send the BSSID. If the first duration is greater than or equal to (or greater than) the preset duration, the slave access point sends a beacon frame carrying the same BSSID, and if the first duration is less than (or less than or equal to) the preset duration, the slave access point does not send a beacon frame carrying the same BSSID. The preset duration is less than the beacon transmission period, for example, the preset duration can be 1 / 2 of the beacon transmission period, 3 / 4 of the beacon transmission period, or other possible values. Moreover, the preset duration is greater than the total duration of the channel occupied by at least one access point sending a beacon frame, and the number of the at least one access point may be the minimum or maximum number of hops or relays required from the first access point to the access point at the edge of the network. The access point at the edge of the network refers to an access point at an edge position in the WLAN system. In this way, a beacon frame can be sent only once from the access point in a beacon sending cycle (e.g., 102400us), preventing the access point from sending beacon frames multiple times within a period of time, and reducing the infinite loop sending of beacon frames.

[0153] Taking the second access point as an example, if the duration (first duration) between the reception time of the currently received beacon frame carrying the first BSSID and the last time the beacon frame carrying the first BSSID was sent (or the last time the beacon frame carrying the first BSSID was triggered to be sent) is less than or equal to the preset duration, then the second access point determines that the beacon sending time has not yet arrived and there is no need to send a beacon frame. If the first duration is greater than the preset duration, then the second access point sends a beacon frame at the current moment. From this perspective, the first duration being greater than the preset duration can be used as a judgment condition (e.g., referred to as the first condition) for the second access point to determine whether to send a beacon frame. If the first condition is met, the second access point determines to send a beacon frame.

[0154] The second access point may record the time of each reception of the beacon frame with the same BSSID and the time of the last transmission of the beacon frame carrying the same BSSID. For example, the time at which the second access point currently receives the beacon frame is recorded as curTsf, and the time at which the second access point transmits the beacon frame before curTsf (i.e., the time at which the last beacon frame was transmitted) is recorded as lastRcvTsf, then the first duration is (curTsf-lastRcvTsf). When (curTsf-lastRcvTsf) is less than or equal to the preset duration, the second access point determines that the beacon transmission time has not yet arrived at the current moment, and there is no need to transmit the beacon frame; when (curTsf-lastRcvTsf) is greater than the preset duration, the second access point determines that the beacon transmission time has arrived, updates lastRcvTsf to curTsf, and transmits the beacon frame at the current moment.

[0155] For easier understanding, see Fig. 7A , which shows a schematic diagram of the principle of an access point determining whether the scheduled beacon sending time has been reached. Fig. 7A Take the WLAN system including AP1-AP3 as an example, wherein AP1 is a master access point, and AP2 and AP3 are slave access points. Fig. 7A Take AP2 and AP3 deciding whether to send a beacon frame as an example. Fig. 7AIn the example, it is assumed that AP1 sends beacon frame 1 at time T1, AP2 receives beacon frame 1 at time T1, and AP3 also receives beacon frame 1 at time T1. AP2 receives beacon frame 1, updates curTsf to T1, and compares it with the last scheduled beacon sending time lastRcvTsf. If curTsf-lastRcvTsf is greater than the preset duration, AP2 determines that the beacon sending time has arrived, and updates lastRcvTsf to curTsf, that is, updates lastRcvTsf to T1. At the same time, AP2 sends a beacon frame (for example, beacon frame 2) at time T2. Similarly, AP3 receives beacon frame 1, updates curTsf to T1, and compares it with the last scheduled beacon sending time lastRcvTsf. If curTsf-lastRcvTsf is greater than the preset duration, AP3 determines that the beacon sending time has arrived, and updates lastRcvTsf to curTsf, that is, updates lastRcvTsf to T1. At the same time, AP3 sends a beacon frame (e.g., beacon frame 3) at time T3. It is understandable that, since AP2 and AP3 use a random backoff mechanism when sending beacon frames, T3 is most likely not equal to T2. For AP2, AP2 will also receive beacon frame 3 sent by AP3. At this time, curTsf = T3, lastRcvTsf = T1. Because the first duration (i.e., T3-T1) is less than or equal to the preset duration, AP2 determines that the beacon sending time has not arrived based on the received beacon frame 3, and does not send a beacon frame ( Fig. 7A Taking this as an example), it is ensured that AP2 sends a beacon frame only once in a beacon sending cycle.

[0156] If an access point receives a beacon frame from another access point with a strong signal strength, it means that the two access points are close to each other and their coverage overlaps a lot. For the terminal, accessing any of the two access points has little impact. Therefore, each slave access point can also determine whether to send a beacon frame based on the signal strength of the received beacon frame, so as to minimize the number of access points that send beacon frames while ensuring the coverage, thereby reducing the number of unnecessary beacon frames demodulated by the terminal and reducing the power consumption of the terminal. "Determining whether to send a beacon frame based on the signal strength of the received beacon frame" can be replaced by "determining whether the beacon sending time is effective based on the signal strength of the received beacon frame". If the beacon sending time is effective, the slave access point sends a beacon frame at the beacon sending time; on the contrary, if the beacon sending time is not effective, the slave access point does not send a beacon frame at the beacon sending time. Regardless of whether the beacon sending time is effective, the access point will update lastRcvTsf to curTsf.

[0157] For example, if the signal strength of the beacon frame received from the access point that meets the first condition is weak (for example, less than or equal to the preset signal strength), then the beacon transmission time takes effect; if the signal strength of the beacon frame received from the access point that meets the first condition is strong (for example, greater than the preset signal strength), it can be considered that the coverage range of the access point and the coverage range of other access points mostly overlap, and the network coverage range can be guaranteed, then the beacon transmission time does not take effect. From this perspective, the signal strength of the beacon frame received from the access point is less than or equal to the preset signal strength, which is the judgment condition (for example, called the second condition) for the second access point to determine whether to send a beacon frame. When the first condition and the second condition are met, the second access point determines to send a beacon frame. In this way, any access point can be prevented from sending beacon frames multiple times in a beacon transmission cycle, and the number of access points sending beacon frames can be reduced, further reducing the possibility of the terminal triggering a roaming process.

[0158] For easier understanding, see Figure 7B , which shows a schematic diagram of the principle of an access point determining whether to send a beacon frame. Figure 7B In the example, AP1 is the master access point, and AP2 and AP3 are slave access points. Assuming that AP2 is closer to AP1 and AP3 is farther from AP1, the signal strength of the beacon frame from AP1 received by AP2 is stronger, while the signal strength of the beacon frame from AP1 received by AP3 is weaker. Figure 7B and Fig. 7A The difference is that AP2 or AP3 not only determines whether the beacon transmission time has arrived, but also determines whether to send a beacon frame at the beacon transmission time. When the signal strength of the beacon frame that meets the first condition is greater than the preset signal strength, AP2 or AP3 does not send a beacon frame either.

[0159] like Figure 7B As shown, AP1 sends beacon frame 1 at time T1, AP2 receives beacon frame 1 at time T1, and AP3 also receives beacon frame 1 at time T1. AP2 receives beacon frame 1, updates curTsf to T1, and compares it with the last beacon sending time lastRcvTsf. When curTSF-lastRcvTsf is greater than the preset duration, AP2 determines that the beacon sending time has arrived. At the same time, AP2 updates lastRcvTsf to curTsf, which is T1. Further, AP2 compares the signal strength of beacon frame 1 with the preset signal strength. If the signal strength of beacon frame 1 is less than the preset signal strength, AP2 sends a beacon at this beacon sending time. If the signal strength of beacon frame 1 is greater than the preset signal strength, AP2 does not send a beacon at this beacon sending time ( Figure 7BTake this as an example). Similarly, AP3 receives beacon frame 1, updates curTsf to T1, and compares it with the last beacon sending time lastRcvTsf. When curTSF-lastRcvTsf is greater than the preset duration, AP3 determines that the beacon sending time has arrived. At the same time, AP3 updates lastRcvTsf to curTsf, which is T1. Further, AP3 compares the signal strength of beacon frame 1 with the preset signal strength. If the signal strength of beacon frame 1 is less than or equal to the preset signal strength, then in order to ensure network coverage, AP3 determines that a beacon needs to be sent at the beacon sending time, and AP3 sends beacon frame 3 ( Figure 7B Take this as an example). It is understandable that, for AP2, AP2 will also receive beacon frame 3 sent by AP3. At this time, curTsf = T3, lastRcvTsf = T1. When the first duration (ie, T3-T1) is less than or equal to the preset duration, AP2 does not send a beacon frame ( Figure 7B Take this as an example).

[0160] Optionally, if the slave access point has not sent a beacon frame, the slave access point may send a beacon frame upon receiving the first beacon frame, and subsequently confirm whether to send a beacon frame according to the method described above.

[0161] The embodiment of the present application also provides a second communication method. The second communication method can make the signal strength of the beacon frame obtained by the terminal stronger, so that the signal strength of the beacon frame received by the terminal is stronger, so as to reduce the triggering of the roaming process.

[0162] In one implementation, the second communication method makes the signal strength of the beacon frame obtained by the terminal stronger based on the multipath effect. For example, the beacon frames sent by different APs to the terminal carry the same BSSID. For the terminal, these different APs are one AP. Based on the multipath effect idea, the beacon frames received from different APs can be superimposed as one beacon frame, so that the signal strength of the beacon frame finally obtained by the terminal is greater. "Superimposing multiple beacon frames" refers to superimposing the signals carrying multiple beacon frames. For ease of understanding, the multipath effect is first introduced.

[0163] The multipath effect refers to the electromagnetic waves emitted by the transmitter reaching the receiver through different paths after being reflected, refracted, and diffracted by multiple objects. Wireless signal transmission will experience the multipath effect, that is, the signal will go through multiple transmission paths when it is sent to the receiving end. Specifically in the WLAN system, the beacon frames of different APs are transmitted to the terminal through different transmission paths. The transmission path from an AP to a terminal can be regarded as a transmission path for the beacon frame to reach the terminal. The beacon frame received by the terminal is the superposition of beacon frames from different APs. The lengths of the transmission paths from beacon frames of different APs to the terminal are different, and the attenuation, phase shift, and time to reach the terminal (i.e., delay) of the signal are all different. Different delays in different paths will bring about phase differences, which will cause different delays of waves of different frequencies, resulting in changes in the waveform of the same frequency. Therefore, after the beacon frames of multiple APs are superimposed, there will be strong and weak signals in the frequency domain.

[0164] For example, see Figure 8 , Figure 8 The figure is a flow chart of two APs sending beacon frames to a terminal via different transmission paths. Figure 8 For example, AP1 sends a beacon frame via path 1 and AP2 sends a beacon frame via path 2. Due to the delays of path 1 and path 2, the time at which the beacon frame sent by AP1 and the beacon frame sent by AP2 arrive at the terminal via path 1 and path 2 may be different. Taking absolute time t as the reference time node, the time at which the beacon frame sent by AP1 arrives at the terminal via path 1 is t1, and the time at which the beacon frame sent by AP2 arrives at the terminal via path 2 is t2. t1 is not equal to t2. The different delays of path 1 and path 2 will cause a phase difference, resulting in different attenuation degrees of the waveforms of beacon frame 1 and beacon frame 2 in the frequency domain, and after superposition, there are strong and weak in the frequency domain.

[0165] In order to increase the signal strength of the beacon frame obtained by the terminal, in the second communication method, multiple APs send the same beacon frame at a short interval as much as possible. Here, "the same beacon frame" means "the waveform of the signal carrying the beacon frame is the same." The beacon frames sent by different APs include the same content, scrambling code and modulation method, so the beacon frames sent by different APs are the same. The scrambling code and modulation method used by each access point to send the beacon frame can be (pre-) configured to be the same, so that multiple APs send beacon frames to achieve a multipath effect. It can be understood that the beacon frames sent by the AP usually carry BSSID, timestamp, etc. For the BSSID, in an embodiment of the present application, the beacon frames sent by different APs to the terminal carry the same BSSID. For the timestamp, in one implementation method, the master access point can indicate the timestamp to be carried by the beacon frame to each slave access point, and each slave access point fills in the timestamp according to the instruction of the master access point, so that the timestamp carried by the beacon frames sent by each access point is consistent. In another implementation, each access point can achieve time synchronization, and the timestamp carried by the beacon frame sent by each access point can be the system time obtained from the respective system clock. Since each access point is time synchronized, it can be considered that the system synchronization of each access point is the same or nearly the same. It should be noted that "each access point sends a beacon frame at the same time" includes each access point sending a beacon frame at a similar time, so that multiple access points achieve a multipath effect.

[0166] The second communication method is described in detail below with reference to the accompanying drawings.

[0167] See also Fig. 9 , is a flow chart of a communication method 900 provided in an embodiment of the present application. The communication method 900 is a second communication method. Fig. 9 Taking the communication method 900 executed by the first access point (AP1), the second access point (AP2) and the terminal as an example, the communication method 900 is introduced from the perspective of the interaction between the first access point, the second access point and the terminal. It should be understood that the communication method 900 can also be implemented by other devices, such as a chip or a communication device with communication functions. Fig. 9 As shown, the process of the communication method 900 includes the following steps.

[0168] S901. A first access point sends a first beacon frame at a first time, where the first beacon frame includes a first BSSID.

[0169] S902. The second access point sends a second beacon frame at a second time, where the second beacon frame includes a first BSSID, wherein the first time and the second time are the same, or an interval between the first time and the second time is less than a preset interval.

[0170] S903: The terminal receives a third beacon frame, where the third beacon frame is a superposition of the first beacon frame and the second beacon frame.

[0171] The first access point and the second access point both send beacon frames at the same time or at a similar time, and the waveforms of the beacon frames sent by the two are the same, so that the beacon frames sent by the first access point and the second access point form a multipath effect. For the terminal, the beacon frame (for example, the third beacon frame) received by the terminal is a superposition of the first beacon frame and the second beacon frame. Relatively speaking, the signal strength of the third beacon frame received by the terminal is greater, thereby reducing the triggering of the roaming process.

[0172] In one scenario, each access point may be time-synchronized. In this case, the first time and the second time may be the scheduled beacon transmission time. It is understandable that the scheduled beacon transmission time of each access point may be determined based on the beacon transmission period and the access point's own clock, wherein the beacon transmission period may be configured by the AC. Since each access point is time-synchronized, it can be considered that the scheduled beacon transmission time of each access point is the same or nearly the same. Any access point sends a beacon frame when it reaches the scheduled beacon transmission time. For example, the first access point sends a first beacon frame when it reaches the scheduled beacon transmission time. The second access point sends a second beacon frame when it reaches the scheduled beacon transmission time.

[0173] The first beacon frame carries a first BSSID and a first timestamp; similarly, the second beacon frame carries a second BSSID and a second timestamp. The first timestamp may be a system time obtained from a system clock of the first access point. The second timestamp may be a system time obtained from a system clock of the second access point. When the time synchronization accuracy of the first access point and the second access point is higher than the accuracy required by the timestamp, the first timestamp set based on the system time of the first access point and the second timestamp set based on the system time of the second access point may be considered to be the same, or the error between the two is very small and within a specified accuracy range, then the two may be considered to be the same. In one implementation, the interval between each access point sending a beacon frame is less than the guard interval (GI), and the time at which each access point sends a beacon frame may be considered to be the same. Accordingly, the time synchronization accuracy of the first access point and the second access point is higher than the GI. For example, in the 802.11ax standard, the GI may be 0.8us (800ns), 1.6us or 3.2us. Assuming that the GI is 800ns, the time synchronization accuracy of the first access point and the second access point may be 80ns.

[0174] It can be understood that GI refers to the interval time set between data blocks to reduce transmission interference. During wireless transmission, the wireless frame is divided into multiple symbol sequences (or databases), and there is multipath interference in the transmission of wireless signals in space. The front end of the next symbol may reach the receiver faster than the end of the previous symbol, resulting in interference between symbols. Therefore, in order to reduce interference, GI is usually set so that there is a blank space between the previous and next symbols as a buffer time.

[0175] In this scenario, each access point only needs to be time synchronized in advance, and the timestamp carried in the beacon frame sent by each access point can be the system time obtained from the respective system clock, and the process is relatively simple.

[0176] In another scenario, the first access point and the second access point are slave access points, and can send beacon frames based on the triggering of the master access point to achieve a multipath effect. In this case, the master access point (e.g., the third access point) can send a timing synchronization frame, which is used to trigger the access point receiving the timing synchronization frame to send a beacon frame at the same time, such as S900. Correspondingly, the first access point and the second access point receive the timing synchronization frame respectively and send a beacon frame.

[0177] The timing synchronization frame includes timestamp information, and the timestamp information can indicate the timestamp to be filled in when the access point receiving the timing synchronization frame sends the beacon frame, so that the timestamps carried by the beacon frames sent from each access point are the same. A timing synchronization frame is received from any access point, and a beacon frame is sent at the first time. The first time can be the sum of the time of receiving the timing synchronization frame and the preset duration. The preset duration can be the abbreviation of short interframe space (SIFS). The third access point can also send a beacon frame (for example, a third beacon frame) at the first time. For example, after the third access point sends the timing synchronization frame, it sends the third beacon frame at an interval of SIFS. In this case, it can be assumed that the interval between the time when the third access point sends the timing synchronization frame and the time when the timing synchronization frame is received from the access point is very small, and can be ignored within the tolerable deviation range. It can be understood that the time synchronization of each access point in advance can make the timestamps carried by the beacon frames sent by each access point the same. Therefore, S900 is not a necessary step. Fig. 9 It is indicated by a dotted line.

[0178] In this scenario, each access point can also send the same beacon frame at the same or similar time to achieve a multipath effect, ultimately making the signal strength of the beacon frame obtained by the terminal greater, thereby reducing the triggering of the roaming process.

[0179] In the above embodiments provided by the present application, the methods provided by the embodiments of the present application are introduced from the perspective of the interaction between the access point and the terminal device. Among them, the steps performed by the access point can be implemented by different functional entities that constitute the access point. The steps performed by the terminal device can be implemented by different functional entities that constitute the terminal device. In order to implement the various functions in the methods provided by the above embodiments of the present application, the terminal device and the network device may include a hardware structure and / or a software module, and implement the above functions in the form of a hardware structure, a software module, or a hardware structure plus a software module. Whether a certain function of the above functions is executed in the form of a hardware structure, a software module, or a hardware structure plus a software module depends on the specific application and design constraints of the technical solution.

[0180] Based on the same inventive concept as the first communication method, an embodiment of the present application further provides a first WLAN system. The first WLAN system may include N access points, where N is an integer greater than or equal to 2. The N access points operate on the same channel and use the same SSID. The beacon frames sent by the N access points carry the same BSSID, and each access point uses a higher modulation order to send the beacon frame. For example, the modulation order used by each access point is greater than 64-QAM. The first WLAN system can make the signal strength of the beacon frame received by the terminal stronger, thereby reducing the triggering of the terminal roaming process.

[0181] In one scenario, N access points are not divided into master and slave. These N access points can be time synchronized. Each access point sends a beacon frame when it reaches the scheduled beacon sending time. The timestamp carried by the beacon frame sent by each access point can be the system time obtained from the system clock. For details, please refer to the above Figure 4 The contents related to the embodiments will not be repeated here.

[0182] In another scenario, the N access points include a master access point and N-1 slave access points, and the timestamp carried by the beacon frame sent by each slave access point may be the sum of the timestamp carried by the received beacon frame and the processing delay, or a preset timestamp. Optionally, each slave access point may decide whether to send a beacon frame. For example, each slave access point sends a beacon frame when a first condition is met; otherwise, the beacon frame is not sent. For another example, each slave access point sends a beacon frame when a first condition and a second condition are met; otherwise, the beacon frame is not sent. This can reduce the number of access points that send beacon frames, thereby reducing the number of unnecessary beacon frames demodulated by the terminal and reducing the power consumption of the terminal. For details, please refer to the aforementioned Figure 4 The relevant contents of the embodiment will not be repeated here.

[0183] Based on the same inventive concept as the second communication method, the embodiment of the present application also provides a second WLAN system. The second WLAN system may include N access points, where N is an integer greater than or equal to 2. The N access points work on the same channel and use the same SSID. The N access points use the same modulation mode and scrambling code to send beacon frames at the same time or similar time, and the contents of the beacon frames sent by the N access points are the same, so that the beacon frames sent by the N access points form a multipath effect, and ultimately the signal strength of the beacon frames received by the terminal is strong, thereby reducing the triggering of the terminal roaming process.

[0184] In one scenario, N access points are not divided into master and slave. These N access points can be time synchronized. Each access point sends a beacon frame when it reaches the scheduled beacon sending time. The timestamp carried by the beacon frame sent by each access point can be the system time obtained from the system clock. For details, please refer to the above Fig. 9 The contents related to the embodiments will not be repeated here.

[0185] In another scenario, N access points include a master access point and N-1 slave access points. The master access point sends a timing synchronization frame to each slave access point to instruct each slave access point to send a timestamp carried in a beacon frame, so that the timestamps carried in the beacon frames sent by each access point are the same. For details, please refer to the aforementioned Fig. 9 The relevant contents of the embodiment will not be repeated here.

[0186] Based on the same inventive concept, the present application also provides a communication device for implementing the first communication method and the second communication method. Therefore, the above contents can be used in subsequent embodiments, and repeated contents will not be repeated.

[0187] Fig.10 1 is a schematic block diagram of a communication device 1000 provided in an embodiment of the present application. The communication device 1000 may be the first access point, the second access point, or the third access point or the terminal device in the above embodiment. For example, the communication device 1000 may be Figure 1The communication device 1000 is an access point or terminal device in the communication device; or, the communication device 1000 is a chip (system) in the access point or a chip (system) in the terminal device; or, the communication device 1000 is a software module of the access point or the terminal device. The communication device 1000 can implement the functions or steps implemented by the terminal device or the first access point or the second access point or the third access point in the above-mentioned various method embodiments. The communication device 1000 may include a processing module 1010 and a transceiver module 1020. Optionally, a storage module may be included, which may be used to store instructions (codes or programs) and / or data. The storage module may be, for example, a memory. The processing module 1010 and the transceiver module 1020 may be coupled to the storage module. For example, the processing module 1010 may read instructions (codes or programs) and / or data in the storage module to implement the corresponding method. When the communication device 1000 is a chip in the terminal device, the storage module may be a storage module in the chip, such as a register, a cache, etc. For example, the storage module may also be a storage module located outside the chip in the network device / terminal device, such as a read-only memory (ROM) or other types of static storage devices that can store static information and instructions, a random access memory (RAM), etc. The above-mentioned units may be independently arranged or partially or fully integrated.

[0188] In one possible implementation, the processing module 1010 may be a processor or controller, such as a CPU, a general-purpose processor, a DSP, an ASIC, an FPGA or other programmable logic device, a transistor logic device, a hardware component or any combination thereof. It may implement or execute various exemplary logic blocks, modules and circuits described in conjunction with the disclosure of this application. The processor may also be a combination that implements a computing function, such as a combination of one or more microprocessors, a combination of a DSP and a microprocessor, and the like. The transceiver module 1020 is a transceiver, an interface circuit, a bus, a pin or other possible communication interface for receiving signals from other devices. For example, when the device is implemented in the form of a chip, the transceiver module 1020 is an interface circuit for the chip to receive signals from other chips or devices, or an interface circuit for the chip to send signals to other chips or devices.

[0189] In some possible implementations, the communication device 1000 can implement the behaviors and functions of the first access point or the second access point in the above method embodiments. The communication device 1000 can be an access point, or a component (such as a chip or circuit) used in an access point, or a chip or a chipset in an access point or a part of a chip used to perform related method functions, or a software module that can implement the method performed by the first access point or the second access point or the third access point in the above method (such as communication method 400, communication method 900), without limitation.

[0190] For example, the communication device 1000 is a first access point, the processing module 1010 can generate a first beacon frame using a modulation order greater than or equal to the first modulation order, and the transceiver module 1020 can send the first beacon frame, and the first beacon frame includes a first BSSID. The communication device 1000 is a second access point, the processing module 1010 can generate a second beacon frame using a modulation order greater than or equal to the second modulation order, and the transceiver module 1020 can send the second beacon frame, and the second beacon frame includes the first BSSID. For details, please refer to the above-mentioned communication method 400 embodiment, which will not be repeated here.

[0191] For another example, the communication device 1000 is a first access point, and the processing module 1010 can determine to send a first beacon frame at a first time, and the first beacon frame carries a first BSSID and a first timestamp; the transceiver module 1020 can send the first beacon frame at the first time. The communication device 1000 is a second access point, and the processing module 1010 can determine to send a second beacon frame at a second time, and the second beacon frame carries a first BSSID and a second timestamp; the transceiver module 1020 can send the second beacon frame at the second time. The first time and the second time are the same or close. The first timestamp and the second timestamp are the same, please refer to the above-mentioned communication method 900 embodiment for details, which will not be repeated here.

[0192] When the communication device 1000 is a chip-type device or circuit, the transceiver module 1020 may be an input / output circuit and / or a communication interface; the processing module 1010 is an integrated processor or microprocessor or integrated circuit.

[0193] Fig.11 1 is a schematic block diagram of a communication device 1100 provided in an embodiment of the present application. The communication device 1100 may be a first access point, a second access point or a terminal device in the above embodiment. For example, the communication device 1100 may be Figure 1 The access point or terminal device in the communication device 1100; or the communication device 1100 is a chip (system) in the access point or terminal device. In the embodiment of the present application, the chip system can be composed of a chip, or can include a chip and other discrete devices. For specific functions, please refer to the description in the above method embodiment.

[0194] The communication device 1100 includes one or more processors 1101, which are used to implement or support the communication device 1100 to implement the functions of the terminal device or the first access point or the second access point or the third access point in the method provided in the embodiment of the present application. Please refer to the detailed description in the method example for details, which will not be repeated here. The processor 1101 may also be referred to as a processing unit or a processing module, which can implement certain control functions. The processor 1101 may be a general-purpose processor or a dedicated processor, etc. For example, it includes: a baseband processor, a central processing unit, an application processor, a modem processor, a graphics processor, an image signal processor, a digital signal processor, a video codec processor, a controller, a memory, and / or a neural network processor, etc. The baseband processor can be used to process communication protocols and communication data. The central processing unit can be used to control the communication device 1100 (such as a network device or a terminal device), execute software programs and / or process data. Different processors can be independent devices or integrated in one or more processors, for example, integrated in one or more application-specific integrated circuits.

[0195] In one design, the processor 1101 may include a program 1103 (sometimes also referred to as code or instruction), and the program 1103 may be executed on the processor 1101 to enable the communication device 1100 to perform the method described in the following embodiments. In another possible design, the communication device 1100 includes a circuit ( Fig.11 (not shown), the circuit is used to implement the first access point or the second access point or the terminal device function in the above embodiments.

[0196] In one design, the communication device 1100 may include one or more memories 1102 on which a program 1104 (sometimes referred to as code or instruction) is stored. The program 1104 may be executed on the processor 1101 so that the communication device 1100 performs the method described in the above method embodiment, for example Figure 4 or Fig. 9 The process shown.

[0197] In one design, the processor 1101 and / or the memory 1102 may include an artificial intelligence (AI) module 1107 and an AI module 11010, and the AI ​​module is used to implement AI-related functions. The AI ​​module may be implemented by software, hardware, or a combination of software and hardware. For example, the AI ​​module may include a RAN intelligent controller (RAN intelligent controller, RIC) module. For example, the AI ​​module may be a near real-time RIC or a non-real-time RIC.

[0198] In a possible design, data may also be stored in the processor 1101 and / or the memory 1102. The processor and the memory may be provided separately or integrated together.

[0199] In a possible design, the communication device 1100 may also include a transceiver 1105 and / or an antenna 1106. The processor 1101 may also be sometimes referred to as a processing unit, which controls the communication device 1100. The transceiver 1105 may also be sometimes referred to as a transceiver unit, a transceiver, a transceiver circuit, or a transceiver, etc., which is used to implement the transceiver function of the communication device through the antenna 1106.

[0200] In a possible design, the communication device 1100 may also include one or more of the following components: a wireless communication module, an audio module, an external memory interface, an internal memory, a universal serial bus (USB) interface, a power management module, an antenna, a speaker, a microphone, an input / output module, a sensor module, a motor, a camera, or a display screen, etc. It is understood that in some embodiments, the communication device 1100 may include more or fewer components, or some components may be integrated, or some components may be separated. These components may be implemented in hardware, software, or a combination of software and hardware.

[0201] The communication device in the above embodiment may be an access point (or terminal device), or a circuit, or a chip applied to an access point (or terminal device) or other combined devices, components, etc. having the above access point (or terminal device). When the communication device is an access point (or terminal device), the transceiver module may be a transceiver, which may include an antenna and a radio frequency circuit, etc., and the processing module may be a processor, such as a CPU. When the communication device is a component having the function of the above access point (or terminal device), the transceiver module may be a radio frequency unit, and the processing module may be a processor. When the communication device is a chip system, the communication device may be an FPGA, a dedicated ASIC, a system on chip (SoC), a CPU, a network processor (NP), a DSP, a microcontroller unit (MCU), a programmable logic device (PLD) or other integrated chips. The processing module may be a processor of a chip system. The transceiver module or the communication interface may be an input / output interface or an interface circuit of a chip system. For example, the interface circuit may be a code / data read / write interface circuit. The interface circuit can be used to receive code instructions (the code instructions are stored in the memory, can be read directly from the memory, or can be read from the memory through other devices) and transmit them to the processor; the processor can be used to run the code instructions to execute the method in the above method embodiment. For another example, the interface circuit can also be a signal transmission interface circuit between the communication processor and the transceiver.

[0202] The present application also provides a computer-readable storage medium including instructions, which, when executed on a computer, causes the computer to execute Figure 4 or Fig. 9 A method executed by a terminal device or a first access point or a second access point or a third access point.

[0203] The present application also provides a computer program product, including instructions, which, when executed on a computer, causes the computer to execute Figure 4 or Fig. 9 A method executed by a terminal device or a first access point or a second access point or a third access point.

[0204] The embodiment of the present application provides a chip system, which includes a processor and may also include a memory, for implementing the functions of the terminal device or the first access point or the second access point in the aforementioned method. The chip system may be composed of a chip, or may include a chip and other discrete devices.

[0205] In order to achieve the above Figure 10-11 In order to realize the functions of the communication device, the embodiment of the present application further provides a chip, including a processor, for supporting the communication device to realize the functions involved in the terminal device or the first access point or the second access point in the above method embodiment. In one possible design, the chip is connected to a memory or the chip includes a memory, and the memory is used to store the computer programs or instructions and data necessary for the communication device.

[0206] In the embodiments of the present application, "when", "if" and "if" all mean that the device will make corresponding processing under certain objective circumstances. They do not limit the time, nor do they require that the device must have a judgment action when it is implemented, nor do they mean that there are other limitations. Unless otherwise specified, "if" and "if" are interchangeable, and "when" and "in the case of" are interchangeable. "When" and "if" / "if" are interchangeable.

[0207] For the number of nouns, unless otherwise specified, it means "singular noun or plural noun", that is, "one or more". "Multiple" means two or more. In view of this, in the embodiments of the present application, "multiple" can also be understood as "at least two". "At least one" can be one or more, for example, at least one is one, two or more. For example, including at least one means including one, two or more, and there is no limit on which ones are included. For example, including at least one of A, B and C, then A, B, C, A and B, A and C, B and C, or A and B and C can be included. Similarly, the understanding of descriptions such as "at least one" is also similar. "At least one of the following items (items)" or similar expressions refers to any combination of these items, including any combination of single items (items) or plural items (items). For example, "at least one of A, B and C" includes A, B, C, AB, AC, BC or ABC. "And / or" describes the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character “ / ”, unless otherwise specified, generally indicates that the previous and next associated objects are in an “or” relationship.

[0208] Unless otherwise specified, ordinal numbers such as "first" and "second" mentioned in the embodiments of the present application are used to distinguish multiple objects, and are not used to limit the order, timing, priority or importance of the multiple objects, and the description of "first" and "second" does not necessarily limit the objects to be different. For example, the first access point and the second access point represent two access points, and do not limit the priority or importance of the two access points.

[0209] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0210] Those of ordinary skill in the art will appreciate that the various illustrative logical blocks and steps described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0211] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0212] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0213] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0214] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the part of the technical solution of the present application that contributes essentially or the part of the technical solution can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as USB flash drives, mobile hard disks, read-only memories (ROM), RAM, magnetic disks or optical disks.

[0215] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A wireless local area network (WLAN) system, characterized in that: comprising a plurality of access points, the plurality of access points comprising a first access point and a second access point; The first access point is used to send a first beacon frame, where the first beacon frame includes a first service set identifier BSSID; The second access point is used to send a second beacon frame, where the second beacon frame includes the first BSSID; The first beacon frame is modulated with a first modulation order, and the second beacon frame is modulated with a second modulation order, and both the first modulation order and the second modulation order are higher than or equal to a modulation order threshold.

2. The WLAN system according to claim 1, wherein: The modulation order threshold is determined according to a signal strength threshold.

3. The WLAN system according to claim 2, wherein: The modulation order threshold is greater than or equal to the modulation order corresponding to the signal strength threshold, and the modulation order corresponding to the signal strength threshold is: when the corresponding modulation order is used to modulate the signal, if the signal strength of the signal received by the receiving end is greater than or equal to the signal strength threshold, the receiving end can demodulate the received signal.

4. The WLAN system according to claim 2 or 3, characterized in that: The signal strength threshold is determined according to the signal strength corresponding to the terminal triggering roaming.

5. The WLAN system according to any one of claims 1 to 4, characterized in that: The first modulation order and the second modulation order are both higher than or equal to 64-quadrature amplitude modulation QAM.

6. The WLAN system according to any one of claims 1 to 5, characterized in that: The second access point is used to send a second beacon frame, including: When the first duration is greater than a preset duration, the second access point sends the second beacon frame; The first duration is the time interval between a first moment and a second moment, the first moment is the moment when the second access point most recently receives a beacon frame carrying the first BSSID, and the second moment is the moment when the second access point last sends a beacon frame carrying the first BSSID, or the second moment is the moment when the second access point last receives a beacon frame that triggers the second access point to send a beacon frame carrying the first BSSID.

7. The WLAN system according to claim 6, characterized in that: The signal strength of the most recently received beacon frame carrying the first BSSID is lower than a preset threshold.

8. The WLAN system according to claim 6 or 7, characterized in that: The preset duration is less than a beacon sending period, and the preset duration is greater than a total duration of a channel occupied by at least one access point in the WLAN system sending a beacon frame.

9. The WLAN system according to any one of claims 1 to 8, characterized in that: The first beacon frame and the second beacon frame carry the same timestamp.

10. A wireless local area network (WLAN) system, characterized in that: include: A first access point, configured to send a first beacon frame at a first time, wherein the first beacon frame includes a first service set identifier BSSID; A second access point, configured to send a second beacon frame at the second time, wherein the second beacon frame includes the first BSSID; A terminal device, configured to receive a third beacon frame, where the third beacon frame is obtained according to the first beacon frame and the second beacon frame; The first time and the second time are the same, or the time interval between the first time and the second time is less than a preset interval.

11. The WLAN system according to claim 10, characterized in that: The third beacon frame is obtained according to the first beacon frame and the second beacon frame, comprising: The signal carrying the third beacon frame is a superposition of the signal carrying the first beacon frame and the signal carrying the second beacon frame.

12. The WLAN system according to claim 10 or 11, characterized in that: The second beacon frame and the first beacon frame respectively include the same content, adopted scrambling code, and modulation and coding strategy MCS.

13. The WLAN system according to any one of claims 10 to 12, characterized in that: The first access point is further configured to: A timing synchronization frame is received from a third access point, where the timing synchronization frame is used to trigger the first access point to send the first beacon frame.

14. The WLAN system according to claim 13, wherein: The timing synchronization frame includes a timestamp, and the timestamp instructs an access point receiving the timing synchronization frame to add the timestamp to a beacon frame to be transmitted.

15. The WLAN system according to claim 10, wherein: The first time and the second time are both scheduled beacon transmission times, and the scheduled beacon transmission times of different access points are the same.

16. The WLAN system according to claim 10, wherein: The preset interval is less than or equal to a guard interval GI, and a time synchronization accuracy between the first access point and the second access point is higher than the GI.

17. A communication method, characterized in that: include: The access point generates a first beacon frame, the first beacon frame includes a first service set identifier BSSID, the first beacon frame is modulated with a first modulation order, and the first modulation order is higher than or equal to a modulation order threshold; The access point sends the first beacon frame.

18. The method according to claim 17, characterized in that The modulation order threshold is determined according to a signal strength threshold.

19. The method according to claim 18, characterized in that The modulation order threshold is greater than or equal to the modulation order corresponding to the signal strength threshold, and the modulation order corresponding to the signal strength threshold is: when the corresponding modulation order is used to modulate the signal, if the signal strength of the signal received by the receiving end is greater than or equal to the signal strength threshold, the receiving end can demodulate the received signal.

20. The method according to any one of claims 17 to 19, characterized in that The access point sends a first beacon frame, including: When the first duration is greater than a preset duration, the access point sends the first beacon frame; The first duration is the time interval between a first moment and a second moment, the first moment is the moment when the access point most recently receives a beacon frame carrying the first BSSID, and the second moment is the moment when the access point last sends a beacon frame carrying the first BSSID, or the second moment is the moment when the access point last receives a beacon frame that triggers the access point to send a beacon frame carrying the first BSSID.

21. The method of claim 20, wherein: The signal strength of the most recently received beacon frame carrying the first BSSID is lower than a preset threshold.

22. The method according to claim 20 or 21, characterized in that The preset duration is less than a beacon sending period, and the preset duration is greater than a total duration of a channel occupied by at least one access point in the WLAN system sending a beacon frame.

23. A communication method, characterized in that: include: The terminal receives a third beacon frame, where the third beacon frame is obtained according to a first beacon frame and a second beacon frame, where the first beacon frame includes a first service set identifier BSSID, and the second beacon frame includes the first BSSID.

24. The method of claim 23, wherein: The third beacon frame is obtained according to the first beacon frame and the second beacon frame, comprising: The signal carrying the third beacon frame is a superposition of the signal carrying the first beacon frame and the signal carrying the second beacon frame.

25. The method according to claim 23 or 24, characterized in that The second beacon frame and the first beacon frame respectively include the same content, adopted scrambling code, and modulation and coding strategy MCS.

26. The method according to any one of claims 23 to 25, characterized in that The sending of the first beacon frame is triggered by a timing synchronization frame, and the sending of the second beacon frame is triggered by a timing synchronization frame.

27. The method of claim 26, wherein: The timing synchronization frame includes a timestamp, and the timestamp instructs an access point receiving the timing synchronization frame to add the timestamp to a beacon frame to be transmitted.

28. The method of claim 23, wherein: The sending time of the first beacon frame is a first time, the sending time of the second beacon frame is a second time, the first time and the second time are the same, or the interval between the first time and the second time is less than a preset interval.

29. The method of claim 28, wherein: The preset interval is less than or equal to a guard interval GI, and a time synchronization accuracy between a first access point that sends the first beacon frame and a second access point that sends the second beacon frame is higher than the GI.

30. A communication method, characterized in that: include: The access point receives a timing synchronization frame; In response to receiving the timing synchronization frame, the access point sends a first beacon frame, the first beacon frame including a first service set identifier (BSSID).

31. The method of claim 30, wherein: The timing synchronization frame includes a timestamp, and the timestamp instructs an access point receiving the timing synchronization frame to add the timestamp to a beacon frame to be transmitted.

32. A communication device, characterized in that: The communication device comprises a processing unit and a transceiver unit, wherein the processing unit is coupled to the transceiver unit to execute the method according to any one of claims 17 to 22, or the method according to any one of claims 23 to 29, or the method according to any one of claims 30 to 31.

33. A communication device, characterized in that: The communication device includes a processor and a memory, the memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory, so that the communication device performs the method as described in any one of claims 17 to 22, or the communication device performs the method as described in any one of claims 23 to 29, or the communication device performs the method as described in any one of claims 30 to 31.

34. A computer-readable storage medium, characterized in that: The computer-readable storage medium is used to store a computer program. When the computer program is run on a computer, the computer executes the method as claimed in any one of claims 17 to 22, or the computer executes the method as claimed in any one of claims 23 to 29, or the computer executes the method as claimed in any one of claims 30 to 31.

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