Network topology identification method, device and wireless communication system

Abstract

The present application provides a method, device and wireless communication system for identifying a network topology. In the solution provided by the present application, the network topology between the first AP, the second AP and the target terminal determined by the controller includes not only the path loss between the two APs, but also the path loss between the AP and the terminal. Since the path loss between the AP and the terminal can not only accurately reflect the signal transmission performance of the link between the AP and the terminal, but also can accurately reflect the degree of interference between downlink signals sent by different APs, the reliability of the network topology is relatively high. Furthermore, it can ensure that the effect of managing and controlling the AP (such as radio frequency tuning) based on the network topology is better.

Description

Technical Field

[0001] The present application relates to the field of communications, and in particular to a method and device for identifying network topology and a wireless communication system. Background Art

[0002] Fit access point (FIT AP) AP is a centralized wireless local area network (WLAN) architecture. A WLAN using the FIT AP architecture mainly includes an access controller (AC), multiple APs, and at least one station (STA). Among them, the AP can provide wireless access services for the STA, and the AC can manage and control multiple APs in a unified manner.

[0003] In order to improve the system performance of WLAN, the AC can also determine the network topology between APs based on the path loss between APs (referred to as path loss), and then manage each AP based on the network topology.

[0004] In the actual deployment scenario of WLAN, if there is an obstruction between two APs that are close to each other, the path loss between the two APs detected by the AC will be small, and the distance between the two APs will be determined to be far. The AC will adjust the transmit power of the two APs to a higher level. However, if there is no obstruction between the two APs and the STA, there will be serious interference between the downlink signals of the two APs. Based on the above analysis, it can be seen that the reliability of the network topology determined based on the path loss between APs is low. Summary of the invention

[0005] The present application provides a network topology identification method, device and wireless communication system, which can solve the technical problem of low reliability of network topology determined based on path loss between APs. The technical solution is as follows:

[0006] On the one hand, a method for identifying a network topology is provided, the method comprising: a controller determines a network topology between a first AP, a second AP, and a target terminal, wherein the target terminal is associated with the first AP, the second AP is a neighbor AP of the first AP, and the network topology comprises: a first path loss, a second path loss, and a third path loss; the first path loss is the path loss between the first AP and the target terminal, the second path loss is the path loss between the second AP and the target terminal, and the third path loss is the path loss between the first AP and the second AP.

[0007] In the solution provided by the present application, the network topology determined by the controller includes not only the path loss between the two APs, but also the path loss between the AP and the terminal. Since the path loss between the AP and the terminal can accurately reflect the signal transmission performance of the link between the AP and the terminal, and can accurately reflect the degree of interference between downlink signals sent by different APs, the reliability of the network topology is relatively high. Furthermore, it can ensure that the reliability of AP management and control (such as RF tuning) based on the network topology is relatively high.

[0008] Optionally, the method may also include: determining the AP with the smallest path loss between the first AP and multiple neighboring APs of the first AP and the target terminal as the home AP to which the target terminal belongs; and determining the ideal coverage range of the home AP based on the terminals belonging to the home AP.

[0009] The ideal coverage range of the home AP can be used for radio frequency tuning so that all terminals within the ideal coverage range can be associated with the home AP. That is, radio frequency tuning based on the ideal coverage range can enable all terminals to be associated with the AP with the smallest path loss. In this way, it can be ensured that the AP does not need a very high transmission power to make the terminal's received signal strength meet the communication quality requirements, and thus interference caused by excessive AP power can be avoided while ensuring the signal coverage quality of the AP.

[0010] Optionally, the method may also include: for any AP among the first AP and the second AP, determining whether any AP is a high-hanging AP based on the path loss between the any AP and the multiple terminals, where the high-hanging AP refers to an AP whose distance to the multiple terminals is greater than a distance threshold, or an AP where there are obstructions to the multiple terminals.

[0011] If the controller identifies an AP as a high-hanging AP, it can be determined that the path loss between the AP and the terminal is large. Accordingly, during subsequent radio frequency tuning, the transmit power of the high-hanging AP can be adjusted higher to ensure that the received signal strength of the terminal can meet the communication quality requirements.

[0012] Optionally, the multiple terminals may be terminals located within an ideal coverage range of any AP; based on the path loss between any AP and the multiple terminals, the process of determining whether any AP is a high-hanging AP may include: if the path loss between any AP and the terminals located within an ideal coverage range of any AP is greater than a first loss threshold, determining that any AP is a high-hanging AP.

[0013] If the path loss between the AP and the terminals within its ideal coverage range is large, the controller can determine that the deployment location of the AP is far away from the distribution plane of the terminals, or there are obstructions between the deployment location of the AP and the distribution plane of the terminals, and thus determine that any AP is a high-hanging AP.

[0014] Optionally, the method may also include: if the path loss between the first AP and the terminal located within the ideal coverage range of the first AP is less than a second loss threshold, the path loss between the second AP and the terminal located within the ideal coverage range of the first AP is less than the second loss threshold, and the third path loss between the first AP and the second AP is greater than a third loss threshold, then it is determined that there is an obstruction between the first AP and the second AP.

[0015] The shielding conditions between APs determined by the controller may also be used as a basis for subsequent radio frequency tuning of the APs, so as to improve the reliability of the radio frequency tuning.

[0016] Optionally, the method may further include: performing radio frequency tuning on at least one of the first AP and the second AP based on the network topology between the first AP, the second AP and the target terminal.

[0017] Since the network topology determined by the controller can also reflect the signal transmission performance between the AP and the terminal, the effect of performing radio frequency tuning based on the network topology is better.

[0018] Optionally, the method may also include: for any AP among the first AP and the second AP, based on the path loss between the any AP and a terminal located within an ideal coverage range of the any AP, adjusting the transmission power of the any AP so that the strength of the signal sent by the any AP detected by the terminal located within the ideal coverage range of the any AP is greater than a strength threshold.

[0019] Based on the above power adjustment method, it can be ensured that all terminals within the ideal coverage range of any AP are associated with the AP, thereby avoiding interference caused by excessive power of the AP while ensuring the signal coverage quality of the AP.

[0020] Optionally, the method may also include: allocating a channel of a first frequency to the first AP, and allocating a channel of a second frequency to the second AP; wherein, if the path loss between the first AP and the terminal located within the ideal coverage range of the second AP is greater than a fourth loss threshold, and the path loss between the second AP and the terminal located within the ideal coverage range of the first AP is greater than the fourth loss threshold, then the frequency difference between the first frequency and the second frequency is less than the first frequency threshold, that is, the frequencies of the channels allocated to the two APs may be equal or similar; if the path loss between the first AP and the terminal located within the ideal coverage range of the second AP is less than a fifth loss threshold, or the path loss between the second AP and the terminal located within the ideal coverage range of the first AP is less than the fifth loss threshold, then the frequency difference between the first frequency and the second frequency is greater than the second frequency threshold, that is, the frequencies of the channels allocated to the two APs are quite different; wherein the fourth loss threshold is greater than or equal to the fifth loss threshold, and the first frequency threshold is less than or equal to the second frequency threshold.

[0021] The controller can allocate channels with the same or similar frequencies to the two APs when it is determined that the interference between the downlink signals of the two APs is small, and can allocate channels with different frequencies to the two APs when it is determined that the interference between the downlink signals of the two APs is large to avoid co-channel interference. Since the number of channels that can be allocated in the system is limited, based on the above channel allocation method, it can be ensured that the co-channel interference of the entire system is small.

[0022] Optionally, the method may also include: receiving a first received signal strength and a second received signal strength sent by the first AP, both of which are sent by the target terminal to the first AP; wherein the first received signal strength is the strength of a first measurement frame sent by the first AP detected by the target terminal, the first measurement frame carries a basic service set identifier (BSSID) of the first AP, and the first received signal strength is used to determine the first path loss; the second received signal strength is the strength of a second measurement frame sent by the second AP detected by the target terminal, the second measurement frame carries the BSSID of the first AP, and the second received signal strength is used to determine the second path loss.

[0023] In the solution provided in the present application, the second AP can disguise itself as the first AP and send a measurement frame to the target terminal associated with the first AP, thereby ensuring that the first AP can obtain the received signal strength of the downlink between the second AP and the target terminal.

[0024] Optionally, the method may also include: before receiving the first received signal strength and the second received signal strength sent by the first AP, sending a detection instruction to the first AP, the detection instruction is used to instruct the first AP to trigger the target terminal to detect the received signal strength; based on the detection result sent by the first AP in the first time period, determining the detection success rate of the target terminal, wherein the detection result is used to indicate whether the first AP has received the received signal strength fed back by the target terminal; if the detection success rate is greater than or equal to the success rate threshold, determining that the target terminal has the ability to detect the received signal strength in the second time period after the current moment; based on the target terminal having the ability to detect the received signal strength, sending a strength measurement instruction for the target terminal to the first AP, the strength measurement instruction is used to instruct the first AP to obtain the first received signal strength and the second received signal strength; wherein the detection success rate is the ratio of the number of target detection results received in the first time period to the total number of detection results received in the first time period, and the target detection result is used to indicate that the first AP receives the received signal strength fed back by the target terminal.

[0025] In the solution provided in the present application, the controller can start measuring the target terminal after determining that the target terminal has the ability to detect the received signal strength, thereby avoiding the waste of network resources caused by invalid measurements.

[0026] Optionally, the method may further include: using a box plot algorithm to process the detection success rates of the multiple terminals determined in the third time period to obtain the success rate threshold.

[0027] Since the box plot algorithm can truly and intuitively show the distribution of observation values, it can be ensured that the success rate threshold determined based on the box plot algorithm has high reliability.

[0028] Optionally, the first AP has multiple neighbor APs including a second AP. After the multiple neighbor APs are sorted in order of path loss between them and the first AP from small to large, the arrangement number of the second AP can be less than or equal to N, where N is a positive integer less than or equal to the total number of the multiple neighbor APs.

[0029] Since the neighbor AP with a larger path loss to the first AP has a smaller impact on the first AP, the controller can only consider the neighbor AP with a smaller path loss to the first AP when identifying the network topology. In this way, the amount of calculation in the network topology identification process can be effectively reduced and the efficiency of network topology identification can be improved while ensuring the reliability of the identified network topology.

[0030] On the other hand, a controller is provided, which has the function of implementing the network topology identification method provided by the above aspect. The controller includes at least one module, and the at least one module can be used to implement the network topology identification method provided by the above aspect.

[0031] On the other hand, a controller is provided, which includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, and when the processor executes the computer program, the method for identifying the network topology provided in the above aspects is implemented.

[0032] On the other hand, a computer-readable storage medium is provided, in which instructions are stored. The instructions are executed by a processor to implement the network topology identification method provided in the above aspects.

[0033] In yet another aspect, a computer program product comprising instructions is provided. When the computer program product is run on a computer, the computer is enabled to execute the network topology identification method provided in the above aspect.

[0034] In yet another aspect, a wireless communication system is provided, the system comprising: a plurality of APs, and a controller provided in any of the above aspects connected to the plurality of APs.

[0035] The technical effects obtained by the controller, computer-readable storage medium, computer program product and wireless communication system provided by the above aspects are similar to the technical effects obtained by the corresponding technical means in the network topology identification method provided by the above aspects, and will not be repeated here.

[0036] In summary, the present application provides a method, device and wireless communication system for identifying a network topology. In the solution provided by the present application, the network topology between the first AP, the second AP and the target terminal determined by the controller includes not only the path loss between the two APs, but also the path loss between the AP and the terminal. Since the path loss between the AP and the terminal can not only accurately reflect the signal transmission performance of the link between the AP and the terminal, but also can accurately reflect the degree of interference between downlink signals sent by different APs, the reliability of the network topology is relatively high. Furthermore, it can ensure that the effect of managing and controlling the AP (such as radio frequency tuning) based on the network topology is better. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is a structural diagram of a wireless communication system provided in an embodiment of the present application;

[0038] Figure 2 is a schematic diagram of the structure of another wireless communication system provided in an embodiment of the present application;

[0039] Figure 3 This is a schematic diagram of the channel division of the 5GHz frequency band;

[0040] Figure 4 is a structural diagram of another wireless communication system provided in an embodiment of the present application;

[0041] Figure 5 It is a schematic diagram of a deployment scenario of an AP provided in an embodiment of the present application;

[0042] Figure 6 is a schematic diagram of another AP deployment scenario provided in an embodiment of the present application;

[0043] Figure 7 is a schematic diagram of a network topology provided in an embodiment of the present application;

[0044] Figure 8 is a flow chart of a method for identifying a network topology provided in an embodiment of the present application;

[0045] Fig. 9 It is a schematic diagram of a first AP obtaining a first received signal strength provided by an embodiment of the present application;

[0046] Fig.10 It is a schematic diagram of a first AP obtaining a second received signal strength provided by an embodiment of the present application;

[0047] Fig.11 is a schematic diagram of first measurement information provided by an embodiment of the present application;

[0048] Fig.12 is a schematic diagram of second measurement information provided by an embodiment of the present application;

[0049] Fig.13 is a schematic diagram of an actual coverage range and an ideal coverage range of an AP provided in an embodiment of the present application;

[0050] Fig.14 This is a flow chart of a method for a controller to generate a terminal portrait provided by an embodiment of the present application;

[0051] Fig.15 is a schematic diagram of the structure of a controller provided in an embodiment of the present application;

[0052] Fig.16 is a schematic diagram of the structure of another controller provided in an embodiment of the present application;

[0053] Fig.17 is a structural diagram of another controller provided in an embodiment of the present application;

[0054] Fig.18 It is a structural diagram of another controller provided in an embodiment of the present application. DETAILED DESCRIPTION

[0055] The solution provided by the embodiments of the present application is described in detail below with reference to the accompanying drawings.

[0056] Figure 1 1 is a schematic diagram of a wireless communication system provided by an embodiment of the present application. The system may be a WLAN with a FIT AP architecture using a locally deployed controller, or a WLAN with a cloud-hosted controller management architecture. Figure 1 The system may include: a controller 01, and multiple APs 02, each of which may be connected to the controller 01. In addition, the system may also include at least one terminal 03, and the terminal 03 may be associated with an AP 02 to obtain a wireless access service provided by the associated AP 02. For example, the terminal 03 may first send an association request to an AP 02 that can be detected, and if an AP 02 responds to the association request, the terminal 03 may establish an association with the AP 02.

[0057] In the embodiment of the present application, the controller 01 may be a wireless controller, for example, an AC. Alternatively, the controller 01 may also be a server independent of the AC and capable of communicating with the AP 02. The AP 02 may be a network device such as a router or switch supporting WLAN. The terminal 03 may also be called a STA, which may be a device supporting WLAN such as a mobile phone, a computer, a wearable device, or a smart home device.

[0058] It can be understood that in a WLAN, the wireless access service provided by a single AP 02 may be referred to as a basic service set (BSS), which may be identified by a BSSID, which may be a media access control (MAC) address of the AP 02. The wireless access service provided by multiple APs 02 connected to the same AC may be referred to as an extended service set (ESS), which may be identified by the same service set identifier (SSID).

[0059] Figure 2 is a schematic diagram of the structure of another wireless communication system provided in an embodiment of the present application, such as Figure 2As shown, the system includes not only the controller 01, AP 02 and terminal 03, but also the aggregation switch 04 located at the aggregation layer, the core switch 05 located at the core layer, the firewall 06 and the router 07. Among them, AP 02 is located at the access layer, and it can access the Internet or the wide area network (WAN) through the aggregation switch 04, the core switch 05, the firewall 06 and the router 07 which are cascaded in sequence. Figure 2 It can be seen that the system may further include an access switch 08 located at the access layer, and the access switch 08 may be connected to the aggregation switch 04 and the terminal 03 respectively, so as to access the terminal 03 to the network.

[0060] like Figure 2 As shown, the controller 01 may be located at the convergence layer and connected to multiple APs 02 via a core switch 05. Of course, the controller 01 may also be located at the core layer or other locations, which is not limited in the present embodiment.

[0061] In a WLAN using a FIT AP architecture, the AC can manage and control multiple APs 02 connected to it based on the network topology between the APs 02. For example, the AC can perform radio frequency tuning on the multiple APs 02, where the radio frequency tuning includes adjusting at least one parameter of the AP 02's transmit power and channel.

[0062] Among them, adjusting the transmit power of AP 02 can achieve the adjustment of the strength of the signal sent by AP 02. In addition, the higher the transmit power of AP 02, the stronger the strength of the signal sent by AP 02, the larger the coverage area of ​​AP 02, and the greater the interference to the neighboring AP. Therefore, the principle of AC adjusting the transmit power of AP 02 may include: the closer the distance between AP 02 and the neighboring AP, the smaller the transmit power of AP 02 is adjusted. Among them, the neighboring AP of AP 02 may refer to an AP whose signal can be detected by AP 02, or an AP whose detected signal strength is greater than a certain threshold.

[0063] Adjusting the channel of AP 02 may include at least one of adjusting the frequency of the channel and adjusting the bandwidth of the channel. For example, Figure 3 This is a schematic diagram of the channel division of the 5 GHz frequency band. Figure 3 As shown, the frequency range of the 5GHz band is 5.15GHz to 5.825GHz, and the 5GHz band can be divided into 24 non-overlapping channels with a bandwidth of 20MHz. For example, the frequency band from 5.15GHz to 5.35GHz includes 8 channels with a bandwidth of 20MHz, and the channel numbers of the 8 channels are 36, 40, 44, 48, 52, 56, 60, and 64, respectively. Figure 3It can be seen that WLAN also supports binding several adjacent channels into a channel with a wider bandwidth to provide a higher signal transmission rate. For example, two adjacent channels can be bound into a channel with a bandwidth of 40 MHz.

[0064] The principle of AC adjusting AP 02 channels may include: avoiding allocating channels of the same frequency to adjacent AP 02, that is, the closer the distance between two AP 02, the smaller the probability of allocating channels of the same frequency; the farther the distance between two AP 02, the greater the probability of allocating channels of the same frequency. The channels of the same frequency may refer to channels with the same frequency and bandwidth. The frequency of a channel may refer to the center frequency of the channel.

[0065] In general, the farther the distance between adjacent APs 02 is, the greater the path loss between the adjacent APs 02 is; the closer the distance between adjacent APs 02 is, the smaller the path loss between the adjacent APs 02 is. Therefore, the AC generally determines the network topology of the system based on the path loss between adjacent APs 02. The path loss refers to the loss caused by the propagation of the signal in the path, and the path loss can be equal to the difference between the transmission power of the signal transmitting end and the strength of the signal received by the signal receiving end.

[0066] However, reference Figure 4 It can be seen that WLAN is a three-dimensional space composed of APs and terminals, and the path loss between APs can only reflect the two-dimensional topology of the AP deployment plane, which lacks consideration of the three-dimensional complex space environment. Figure 4 In the example, assuming that terminals STA1 and STA2 are both associated with AP1, and AP2 and AP3 are neighboring APs of AP1, the downlink signals of AP2 and AP3 will interfere with the downlink signals sent by AP1 to STA1 and STA2, thereby affecting the service experience of STA1 and STA2. In other words, the signal transmission between the AP deployment plane and the terminal distribution plane is also an important factor affecting the terminal service experience. However, the two-dimensional topology determined based on the path loss between APs cannot take into account the signal transmission between APs and terminals, resulting in low reliability of the two-dimensional topology.

[0067] Moreover, in actual deployment scenarios, signal refraction, reflection or attenuation caused by spatial environments such as obstruction or high hanging will affect the signal transmission quality between the AP and the terminal. Therefore, RF tuning based on the two-dimensional topology of the AP deployment plane will lead to unsatisfactory tuning results in some complex deployment environments.

[0068] In some possible scenarios, refer to Figure 5 In (a), in a space with a high roof height such as a gymnasium or stairwell, there may be multiple AP 02s (e.g. Figure 5The AP1 and AP2 in the figure are both installed on the roof, and the distance between adjacent APs 02 is relatively close. Figure 5 In (b), in the space below the roof where there is a ceiling (or suspended ceiling), there may be multiple APs 02 that are set between the roof and the ceiling (or suspended ceiling), and the distance between adjacent APs 02 is relatively close. In the above two scenarios, since the path loss between adjacent APs 02 detected by the AC is small, the transmit power of the multiple APs 02 will be adjusted to a lower level. However, due to the distance between AP 02 and the terminal (for example Figure 5 The distance between STA1 in the figure is far, or there is an obstacle such as a ceiling or suspended ceiling between AP 02 and the terminal, so the strength of the signal sent by the AP detected by the terminal is weak. In turn, the negotiation rate between AP 02 and the terminal is reduced, that is, the data transmission rate between AP 02 and the terminal is reduced, which may cause the terminal to be disconnected in severe cases.

[0069] Figure 5 The scenarios shown in (a) and (b) are examples of deployment scenarios of high-hanging APs. In the embodiments of the present application, APs that are far away from the terminal due to their high setting position, or APs that have obstacles such as ceilings or suspended ceilings between them and the terminal can be collectively referred to as high-hanging APs.

[0070] In some other possible scenarios, refer to Figure 6 In (a), there may be a neighboring AP 02 (e.g. Figure 6 The distance between AP1 and AP2 in the figure is close, but there is a beam between them. Figure 6 In (b), there may be a scenario where the distance between adjacent APs 02 is relatively close, but there is a wall with a corner between them. Figure 6 In (c), in a space with an atrium, there may be multiple APs 02 deployed on rooftops of different floors. In the above scenario, since there are shields between adjacent APs 02, the path loss between adjacent APs 02 detected by the AC is large, and the same frequency channels are allocated to the multiple APs 02. However, in the above scenario, if each AP 02 is connected to a terminal (e.g. Figure 6 If there is no obstruction between STA1 in the figure, the same-channel interference on the terminal side may be more serious, which in turn causes the application layer rate of the terminal to decrease and the service experience of the terminal to be poor. Figure 6 The scenarios shown in (a) to (c) are examples of deployment scenarios where there are obstructions between APs.

[0071] Based on the above analysis, it can be seen that in the scenario where AP 02 is set at a high position, there are obstructions between AP 02 and the terminal, or there are obstructions between AP 02, the network topology of the system cannot be accurately determined based only on the path loss between AP 02. Accordingly, the reliability of controlling AP 02 based on this network topology is low.

[0072] The embodiment of the present application provides a method for identifying a network topology, which can solve the technical problem that the reliability of the network topology determined based on the path loss between AP 02 is low. The method provided by the embodiment of the present application can be applied to a controller, for example, Figure 1 or Figure 2 Controller 01 in the system shown.

[0073] In the method provided in the embodiment of the present application, the controller is capable of determining a network topology between a first AP, a second AP, and a target terminal, wherein the target terminal is associated with the first AP, and the second AP is a neighbor AP of the first AP. The network topology includes: a first path loss, a second path loss, and a third path loss, wherein the first path loss is the path loss between the first AP and the target terminal, the second path loss is the path loss between the second AP and the target terminal, and the third path loss is the path loss between the first AP and the second AP.

[0074] It is understandable that the target terminal may be any terminal associated with the first AP. Furthermore, the target terminal may be a user terminal in the WLAN, or may be a test terminal set in the WLAN and dedicated to identifying the network topology, which is not limited in the embodiments of the present application.

[0075] In an embodiment of the present application, the path loss between the AP and the target terminal may refer to the path loss of the downlink between the AP and the target terminal; or, it may refer to the path loss of the uplink between the AP and the target terminal; or, the path loss between the AP and the target terminal may include the path loss of the downlink and the path loss of the uplink.

[0076] The neighbor AP of the first AP may refer to an AP whose signal can be detected by the first AP, or an AP whose detected signal strength is greater than a certain threshold. In addition, the first AP and its neighbor AP may be controlled by the same AC or different ACs, which is not limited in the embodiments of the present application.

[0077] It can be understood that the network topology between the first AP, the second AP and the target terminal determined by the controller may refer to a set of path losses. Figure 7As shown, the set of path losses includes not only the path loss between the first AP and the second AP, but also the path loss between the AP and the terminal, that is, the network topology determined by the solution provided in the embodiment of the present application is a three-dimensional (3-dimension, 3D) network topology. The network topology can fully and truly reflect the propagation of signals in space, as well as the impact of signals on terminals and APs. For example, the path loss between the AP and the terminal can accurately reflect the signal transmission performance of the link between the AP and the terminal, and can accurately reflect the degree of interference between downlink signals sent by different APs. The reliability of the 3D network topology is high, and RF tuning based on the 3D network topology can better adapt to complex and changeable spatial environments and improve the environmental generalization of RF tuning algorithms.

[0078] Figure 8 is a flowchart of a network topology identification method provided by an embodiment of the present application, which can be applied to Figure 1 or Figure 2 In the wireless communication system shown in FIG. 1 , since the path loss of the downlink between the AP and the terminal is an important factor affecting the service experience of the terminal, the path loss between the AP and the terminal is taken as the path loss of the downlink for example.

[0079] refer to Figure 8 , the method may include:

[0080] Step 101: A controller sends a strength measurement instruction for a target terminal to a first AP.

[0081] The target terminal is associated with the first AP, and the strength measurement instruction can be used to instruct the first AP to obtain a first received signal strength, which refers to the strength of the measurement frame sent by the first AP detected by the target terminal, that is, the received signal strength of the downlink between the first AP and the target terminal.

[0082] Optionally, the strength measurement instruction for the target terminal may carry an identifier of the target terminal, for example, may carry a MAC address of the target terminal.

[0083] Step 102: The first AP sends a first measurement frame to the target terminal.

[0084] After the first AP receives the strength measurement instruction for the target terminal sent by the controller, it can send a first measurement frame to the target terminal based on the strength measurement instruction. The first measurement frame can carry the BSSID of the first AP, and the BSSID can be the MAC address of the first AP. The first measurement frame is a WLAN frame, for example, the first measurement frame can be a link measurement request frame, and the link measurement request frame can be used to request a received signal strength indicator (RSSI).

[0085] Example, reference Fig. 9 , assuming that the first AP is AP1 and the target terminal is STA1, AP1 can send a first measurement frame to STA1.

[0086] Step 103: The first AP sends a measurement request to the second AP.

[0087] In a possible implementation, the strength measurement instruction received by the first AP can also be used to instruct the first AP to obtain a second received signal strength. The second received signal strength refers to the strength of the measurement frame sent by the second AP detected by the target terminal, that is, the received signal strength of the downlink between the second AP and the target terminal, and the second AP is a neighbor AP of the first AP. For example, the strength measurement instruction may include an identifier of the second AP (such as the MAC address of the second AP), and the first AP may send a measurement request to the second AP based on the strength measurement instruction. The measurement request may include the BSSID of the first AP and the channel used when the first AP is associated with the target terminal. The measurement request is used to instruct the second AP to disguise itself as the first AP and send a second measurement frame to the target terminal.

[0088] Example, reference Fig.10 , assuming that the second AP is AP2, AP1 can send a measurement request to AP2 after receiving the strength measurement instruction.

[0089] In another possible implementation, the controller may directly send a strength measurement instruction for the target terminal to the second AP, and the strength measurement instruction may include the BSSID of the first AP and the channel used when the first AP is associated with the target terminal. The strength measurement instruction sent to the second AP may be used to instruct the second AP to disguise itself as the first AP and send a second measurement frame to the target terminal.

[0090] In another possible implementation, the second AP pre-stores the BSSID of the first AP and the channel used when the first AP is associated with the target terminal. After receiving the measurement request sent by the first AP or the strength measurement instruction sent by the controller, the second AP can disguise itself as the first AP based on the pre-stored information and send a second measurement frame to the target terminal.

[0091] Step 104: The second AP sends a second measurement frame to the target terminal.

[0092] In an embodiment of the present application, after the second AP receives the measurement request sent by the first AP or the strength measurement instruction sent by the controller, it can send a second measurement frame to the target terminal. The second measurement frame carries the BSSID of the first AP, and the channel used by the second AP to send the second measurement frame is the channel used when the first AP is associated with the target terminal (hereinafter referred to as the target channel). Thus, the second AP can disguise itself as the first AP and send the second measurement frame to the target terminal to ensure that the second measurement frame can be received by the target terminal. For example, refer to Fig.10 , AP2 can send a second measurement frame to STA1 based on the measurement request sent by AP1.

[0093] It is understandable that if the current working channel of the second AP is the same as the target channel, the second AP does not need to switch channels. If the current working channel of the second AP is different from the target channel, the second AP can temporarily switch to the target channel to send the second measurement frame. And, after the second AP sends the second measurement frame through the target channel, it can immediately switch back to the original working channel to avoid affecting other services of the second AP.

[0094] Step 105: The target terminal sends a first measurement response frame to the first AP.

[0095] After receiving the first measurement frame sent by the first AP, the target terminal can obtain the BSSID of the first AP from the first measurement frame, and feed back a first measurement response frame to the first AP based on the BSSID. The first measurement response frame includes the strength of the first measurement frame detected by the target terminal, that is, the first received signal strength. For example, refer to Fig. 9 , STA1 can send a first measurement response frame to AP1.

[0096] Step 106: The target terminal sends a second measurement response frame to the first AP.

[0097] After the target terminal receives the second measurement frame sent by the second AP, since the BSSID carried in the second measurement frame is the BSSID of the first AP, the target terminal can feed back a second measurement response frame to the first AP based on the BSSID of the first AP. The second measurement response frame includes the strength of the second measurement frame detected by the target terminal, that is, the second received signal strength. For example, refer to Fig.10 After receiving the second measurement frame sent by AP2, STA2 may send a second measurement response frame to AP1. The measurement response frame fed back by the target terminal to the first AP may be a link measurement request frame.

[0098] Optionally, the first received signal strength and the second received signal strength may both be represented by RSSI.

[0099] In an embodiment of the present application, if the first AP has multiple neighboring APs including the second AP, as a possible example, the controller can obtain the received signal strength of the downlink between each neighboring AP and the target terminal. That is, each neighboring AP of the first AP can disguise itself as the first AP and send a measurement frame to the target terminal under the instruction of the strength measurement instruction sent by the controller or the measurement request sent by the first AP. Accordingly, the target terminal can feed back a measurement response frame to the first AP for the measurement frame sent by each neighboring AP.

[0100] As another possible example, since the neighbor AP with a large path loss to the first AP has a small impact on the first AP, the controller can only consider the neighbor AP with a small path loss to the first AP when identifying the network topology. In this way, the amount of calculation in the network topology identification process can be effectively reduced and the efficiency of network topology identification can be improved while ensuring the reliability of the identified network topology.

[0101] For example, the controller can sort the multiple neighbors of the first AP in order of the path loss between them and the first AP from small to large, and determine the neighbor APs with an arrangement number less than or equal to N as neighbor APs to be scanned. After that, the controller can obtain the received signal strength of the downlink between each neighbor AP to be scanned and the target terminal. That is, among the multiple neighbor APs of the first AP, only the neighbor APs to be scanned can disguise themselves as the first AP and send measurement frames to the target terminal under the instruction of the strength measurement instruction sent by the controller or the measurement request sent by the first AP. Correspondingly, the target terminal can feedback to the first AP a measurement response frame for each measurement frame sent by the neighbor AP to be scanned. It can be understood that the second AP belongs to the neighbor APs to be scanned, that is, the arrangement number of the second AP is less than or equal to N.

[0102] In the above example, N is a positive integer less than or equal to the total number of the plurality of neighbor APs. When the total number of neighbor APs of the first AP is greater than the number threshold, that is, the number of neighbor APs is large, N may be less than the total number of the plurality of neighbor APs. When the total number of neighbor APs of the first AP is not greater than the number threshold, that is, the number of neighbor APs is small, N may be equal to the total number of the plurality of neighbor APs.

[0103] For example, assuming that N=10, the controller can determine the first 10 neighbor APs with the smallest path loss to the first AP as neighbor APs to be scanned, and can carry the MAC addresses of the 10 neighbor APs in the strength measurement instruction sent to the first AP. The first AP can then send measurement requests to the 10 neighbor APs respectively based on the strength measurement instruction.

[0104] Step 107: The first AP sends the first received signal strength and the second received signal strength to the controller.

[0105] After the first AP receives the first measurement response frame fed back by the target terminal, it can obtain the first received signal strength from the first measurement response frame and send the first received signal strength to the controller. After the first AP receives the second measurement response frame fed back by the target terminal, it can obtain the second received signal strength from the second measurement response frame and send the second received signal strength to the controller.

[0106] It can be understood that since the first AP can be associated with multiple terminals including the target terminal, for each terminal associated with the first AP, the received signal strength of the downlink link between the first AP and the terminal and the received signal strength of the downlink link between the second AP and the terminal can be obtained by the method shown in the above steps 101 to 107.

[0107] Optionally, in an embodiment of the present application, the first AP may send first measurement information and second measurement information to the controller respectively. The first measurement information is measurement information obtained by the first AP measuring its associated terminal (e.g., target terminal), and the second measurement information refers to information measured by the second AP disguised as the first AP to send a measurement frame. In addition to the above-mentioned first received signal strength, the first measurement information may also include information such as the terminal identifier (e.g., MAC address) and the BSSID of the first AP. In addition to the above-mentioned second received signal strength, the second measurement information may also include information such as the terminal identifier, the BSSID of the first AP, and the BSSID of the second AP.

[0108] For example, Fig.11 is a schematic diagram of a first measurement information provided by an embodiment of the present application. Fig.11It can be seen that the first measurement information reported by the first AP to the controller may include the following fields: sta_mac, dl_rssi, dl_linkmargin, sta_tx_power, ul_rssi, tx_rate, rx_rate, radio_id, bssid, ssid, assoc_timestamp, and online_time.

[0109] Among them, the field type of the sta_mac field is byte type, the length is 6 bytes, the field identifier (identifier, ID) is 1, and the sta_mac field is used to carry the MAC address of the terminal (such as the target terminal).

[0110] The field type of the dl_rssi field is character (char), the length is 1 byte, and the field ID is 2. The dl_rssi field is used to carry the received signal strength of the downlink (DL) between the first AP and the terminal detected by the terminal, such as the first received signal strength mentioned above. The received signal strength of the downlink can be represented by RSSI.

[0111] The field type of the dl_linkmargin field is char, the length is 1 byte, the field ID is 3, and the dl_linkmargin field is used to carry the link margin (link margin, LM) of the downlink between the first AP and the terminal measured by the first AP based on the transmit power control request (TPC request; transmit power control, TPC) frame.

[0112] The field type of the sta_tx_power field is an 8-bit unsigned integer (unit8), the length is 1 byte, the field ID is 4, and the sta_tx_power field is used to carry the power (power) used by the terminal when sending a measurement response frame. For example, for a target terminal, the sta_tx_power field can carry the power used by the target terminal to send the first measurement response frame. It can be understood that the power carried by the sta_tx_power field is reported by the terminal to the first AP.

[0113] The field type of the ul_rssi field is char, the length is 1 byte, and the field ID is 5. The ul_rssi field is used to carry the received signal strength of the uplink (UP) between the first AP and the terminal detected by the first AP, that is, the strength of the signal sent by the terminal detected by the first AP. The received signal strength of the uplink can also be represented by RSSI.

[0114] The field type of the tx_rate field is a 32-bit unsigned integer (unit32), the length is 4 bytes, the field ID is 6, and the tx_rate field is used to carry the rate (rate) of the transmit (transmit, TX) link of the first AP, and the unit of the rate is megabits per second (Mbps).

[0115] The field type of the rx_rate field is unit32, the length is 4 bytes, and the field ID is 7. The tx_rate field is used to carry the rate of the receive (RX) link of the first AP, and the unit of the rate is Mbps. Among them, the TX link of the first AP is the downlink between the first AP and the terminal, and the RX link is the uplink between the first AP and the terminal.

[0116] The field type of the radio_id field is unit8, the length is 1 byte, the field ID is 8, and the tx_rate field is used to carry the ID of the radio frequency band in which the first AP currently works. The radio frequency band in which the first AP works can be a 2.4 GHz band or a 5 GHz band.

[0117] The field type of the bssid field is byte, the length is 6 bytes, the field ID is 9, and the bssid field is used to carry the BSSID of the first AP.

[0118] The field type of the ssid field is a string type, the length is 32+1 bytes, and the field ID is 10. The ssid field is used to carry the SSID of the first AP. Among them, 32+1 bytes means that the first 32 bytes are used to carry the SSID, and the last byte is used to carry the terminator.

[0119] The field type of the assoc_timestamp field is unit32, the length is 4 bytes, and the field ID is 11. The assoc_timestamp field is used to carry the timestamp (timestamp) of the terminal accessing the AP with which it is associated (associate, assoc), that is, the first AP.

[0120] The field type of the online_time field is unit32, the length is 4 bytes, and the field ID is 12. The online_time field is used to carry the online duration of the terminal, that is, the duration that the terminal has been connected to the first AP.

[0121] Fig.12 FIG. 1 is a schematic diagram of second measurement information sent by a first AP to a controller according to an embodiment of the present application. Fig.12It can be seen that the second measurement information may include fields such as sta_mac, radio_id, assoc_bssid, assoc_ssid, assoc_dl_val, expected_neighbor_num, neighbor_num, neighbor_bssid_1, and neighbor_dl_val_1.

[0122] Among them, the field type of the sta_mac field is byte type, the length is 6 bytes, the field ID is 1, and the sta_mac field is used to carry the MAC address of the terminal.

[0123] The field type of the radio_id field is unit8, the length is 1 byte, the field ID is 2, and the radio_id field is used to carry the ID of the radio frequency band on which the first AP currently works.

[0124] The assoc_bssid field has a field type of byte, a length of 6 bytes, and a field ID of 3. The assoc_bssid field is used to carry the BSSID of the first AP. It can be understood that since the first AP is an AP associated with the target terminal, it can also be called an associated AP.

[0125] The field type of the assoc_ssid field is string, the length is 32+1 bytes, the field ID is 4, and the assoc_bssid field is used to carry the SSID of the first AP.

[0126] The field type of the assoc_dl_val field is char, the length is 1 byte, the field ID is 5, and the assoc_dl_val field is used to carry the received signal strength of the downlink between the first AP and the terminal.

[0127] The field type of the expected_neighbor_num field is unit8, the length is 1 byte, the field ID is 10, and the expected_neighbor_num field is used to carry the number of neighbor APs expected to be scanned.

[0128] The number of neighboring APs that are expected to be scanned may refer to the number of neighboring APs to which the first AP has sent measurement requests based on the strength measurement instruction. For example, if the controller instructs to obtain the received signal strength of the downlink between each neighboring AP and the target terminal, the first AP may send a measurement request to each neighboring AP, and accordingly, the number of neighboring APs that are expected to be scanned is the total number of neighboring APs included in the first AP. If the controller instructs to obtain only the received signal strength of the downlink between N neighboring APs to be scanned and the target terminal, the first AP may send a measurement request only to N neighboring APs to be scanned, and accordingly, the number of neighboring APs that are expected to be scanned is N.

[0129] The field type of the neighbor_num field is unit8, the length is 1 byte, and the field ID is 6. The neighbor_num field is used to carry the number of valid neighbor APs within a measurement period (eg, 1 second).

[0130] The valid neighbor AP refers to the neighbor AP that sends a measurement frame to the terminal after receiving the measurement request sent by the first AP. It is understandable that after the first AP sends a measurement request to the neighbor AP, some neighbor APs may not respond to the measurement request due to factors such as the inability to switch channels, that is, the neighbor AP does not send a measurement frame to the terminal, which results in the first AP being unable to obtain the received signal strength of the downlink between the neighbor AP and the terminal. Therefore, in an embodiment of the present application, the first AP can also report the number of valid neighbor APs to the controller.

[0131] The field type of the neighbor_bssid field is byte type, the length is 6 bytes, and the field ID is 7. The neighbor_bssid field is used to carry the BSSID of the neighbor AP (eg, the second AP) of the first AP.

[0132] The field type of the neighbor_dl_val field is char, the length is 1 byte, and the field ID is 8. The neighbor_dl_val field is used to carry the received signal strength of the downlink between the neighbor AP and the terminal, for example, it can carry the above-mentioned second received signal strength.

[0133] It can be understood that, for a scenario where the first AP has multiple neighboring APs, the first AP can obtain the received signal strength of the terminal for multiple neighboring APs. Therefore, as a possible example, if the first AP receives the received signal strength of multiple neighboring APs fed back by the terminal within a measurement cycle, the second measurement information may include multiple neighbor_bssid fields and multiple neighbor_dl_val fields, wherein each neighbor_bssid field may carry the BSSID of a neighboring AP, and each neighbor_dl_val field may carry the received signal strength of the downlink between a neighboring AP and the terminal. As another possible example, if the first AP only receives the received signal strength of one neighboring AP fed back by the terminal within a measurement cycle, the second measurement information may carry the BSSID of one neighboring AP and the received signal strength of the downlink between one neighboring AP and the target terminal, and the first AP may report multiple second measurement information to the controller in batches.

[0134] Optionally, in an embodiment of the present application, after receiving the strength measurement instruction for the target terminal, the first AP may send a measurement frame to the target terminal once every first measurement period (e.g., 1 second). Since the target terminal can feed back a first measurement response frame within a time period much shorter than the first time period (e.g., within a few milliseconds) after receiving the measurement frame, the first AP may send the first measurement information to the controller once every first measurement period.

[0135] Since the neighboring AP (e.g., the second AP) may need to switch the working channel to send the second measurement frame after receiving the measurement request or the strength measurement instruction, that is, the time required for the second AP to send the measurement frame is longer, the time required for the first AP to receive the second received signal strength is also longer. Accordingly, the first AP may send the second measurement information to the controller once every second measurement period. The duration of the second measurement period may be greater than or equal to the duration of the first measurement period. For example, the duration of the second measurement period may be 1 to 10 seconds.

[0136] Step 108: The first AP sends a third received signal strength to the controller.

[0137] The third received signal strength refers to the strength of the measurement frame sent by the second AP detected by the first AP, and the third received signal strength can also be represented by RSSI. In an embodiment of the present application, the controller can also periodically send strength detection instructions to each AP it controls according to a preset detection cycle. The AP that receives the strength detection instruction can send a measurement frame to a neighboring AP, and the neighboring AP can then detect the strength of the measurement frame it receives and report the detected strength to the controller. Among them, the duration of the detection cycle can be 1 day.

[0138] For example, the controller can send strength detection instructions to the first AP and the second AP respectively in the early morning every day. The second AP can send a measurement frame to the first AP based on the strength detection instruction. The first AP can detect the strength of the received measurement frame, that is, the third received signal strength, and report the third received signal strength to the controller.

[0139] Step 109: The controller determines a network topology between the first AP, the second AP, and the target terminal based on the first received signal strength, the second received signal strength, and the third received signal strength.

[0140] The network topology includes: a first path loss, a second path loss and a third path loss. The first path loss is the path loss between the first AP and the target terminal, the second path loss is the path loss between the second AP and the target terminal, and the third path loss is the path loss between the first AP and the second AP.

[0141] The controller may determine a first path loss based on the first received signal strength, determine a second path loss based on the second received signal strength, and determine a third path loss based on the third received signal strength. For example, the first path loss is equal to the difference between the transmit power of the first AP and the first received signal strength, the second path loss is equal to the difference between the transmit power of the second AP and the second received signal strength, and the third path loss is equal to the difference between the transmit power of the first AP and the third received signal strength.

[0142] It is understandable that if the controller is an AC, since the transmit powers of the first AP and the second AP are both controlled by the AC, the transmit powers of each AP are stored in the AC. If the controller is a server independent of the AC, the server can obtain the transmit power of each AP sent by the AC, or can obtain the transmit power reported by each AP.

[0143] For the scenario where the first AP has multiple neighbor APs including the second AP, as a possible example, the controller can obtain the received signal strength of the downlink between each neighbor AP and the target terminal. Accordingly, the controller can determine the network topology between the first AP, multiple neighbor APs, and the target terminal. That is, the network topology includes the first path loss, the path loss between each neighbor AP and the target terminal, and the path loss between the first AP and each neighbor AP.

[0144] As another possible example, the controller can determine N neighbor APs to be scanned from the multiple neighbor APs, and the controller can obtain the received signal strength of the downlink between each neighbor AP to be scanned and the target terminal. Accordingly, the controller can determine the network topology between the first AP, the N neighbor APs to be scanned, and the target terminal. That is, the network topology includes the first path loss, the path loss between each neighbor AP to be scanned and the target terminal, and the path loss between the first AP and each neighbor AP to be scanned.

[0145] For example, assuming that the N neighboring APs to be scanned by the controller of the first AP include at least the second AP and the third AP, the path loss between each AP and the target terminal determined by the controller based on the received signal strength reported by the first AP can be as shown in Table 1. Referring to Table 1, it can be seen that the identifier of the first AP is N1_5F_1, and the received signal strength (i.e., the first received signal strength) of the target terminal to the first AP is -50 decibel milliwatts (dBm). Assuming that the transmit power of the first AP is 5dBm, the controller can determine that the first path loss of the downlink between the first AP and the target terminal is 55dBm. The identifier of the second AP is N1_5F_13, and the received signal strength (i.e., the second received signal strength) of the target terminal to the second AP is -60dBm. Assuming that the transmit power of the second AP is 5dBm, the controller can determine that the second path loss of the downlink between the second AP and the target terminal is 65dBm. The identifier of the third AP is N1_5F_26, and the received signal strength of the target terminal to the third AP is -65dBm. Assuming that the transmission power of the third AP is 5 dBm, the controller can determine that the path loss of the downlink between the third AP and the target terminal is 70 dBm.

[0146] Table 1

[0147] AP AP ID Received signal strength Path loss First AP N1_5F_1 -50 55 Second AP N1_5F_13 -60 65 Third AP N1_5F_26 -65 70 ... ... ... ...

[0148] It can also be understood that the first AP can be associated with multiple terminals including the target terminal, and for each terminal, the controller can obtain the path loss between the terminal and the first AP, as well as the path loss between the terminal and each neighbor AP. Therefore, the controller can determine the network topology between the first AP, multiple neighbor APs of the first AP, and multiple terminals associated with the first AP. That is, the network topology determined by the controller may include: the first path loss, the path loss between each neighbor AP of the first AP and each terminal associated with the first AP, and the path loss between the first AP and each neighbor AP.

[0149] Step 110: The controller determines the AP having the smallest path loss with the target terminal among the first AP and a plurality of neighboring APs of the first AP as the home AP to which the target terminal belongs.

[0150] After the controller obtains the path loss between the first AP and the neighboring APs of the first AP and the target terminal, it can also determine the AP with the smallest path loss between the first AP and multiple neighboring APs and the target terminal as the belonging AP to which the target terminal belongs, that is, the belonging AP to which the target terminal belongs refers to the AP with the smallest path loss between the target terminal and the target terminal. It can be understood that, under the premise that there are no obstructions between the target terminal and each AP, the belonging AP of the target terminal is the AP closest to the target terminal. It can also be understood that the belonging AP is not the same as the associated AP associated with the target terminal. Correspondingly, for the belonging AP, the terminal associated with the belonging AP is not the same as the terminal belonging to the belonging AP.

[0151] It can be understood that, for the belonging AP, if the path loss between a terminal and the belonging AP is less than the path loss between the terminal and other APs, the terminal is a terminal belonging to the belonging AP. Alternatively, it can be understood that the terminal belonging to the belonging AP refers to the terminal that should be associated with the belonging AP in an ideal situation.

[0152] Example, reference Fig.13 , assuming that the first AP is AP1, and the target terminal associated with AP1 is STA1. If the path loss between STA1 and AP1 is the smallest, the controller can determine AP1 as the home AP to which STA1 belongs, that is, the home AP and the associated AP of STA1 are both AP1.

[0153] Alternatively, assuming that the first AP is AP2 and the target terminal associated with AP2 is STA2, if the path loss between STA2 and AP1 is the smallest, the controller may determine AP1 as the home AP to which STA2 belongs, that is, the home AP and the associated AP of STA2 are different APs.

[0154] It can be understood that, for each terminal associated with the first AP, the controller can determine the home AP to which the terminal belongs based on the method shown in step 110 above.

[0155] Step 111: The controller determines an ideal coverage range of the home AP based on the terminals belonging to the home AP.

[0156] After the controller determines the AP to which the target terminal belongs, it can also determine the ideal coverage range of the AP based on the terminals belonging to the AP, that is, the area where the terminals belonging to the AP are located can be determined as the ideal coverage range of the AP. Among them, the ideal coverage range of the AP can refer to a coverage range that can both ensure the communication quality requirements of the terminals within the range and avoid interference with downlink signals between APs. It can be understood that the ideal coverage range determined by the controller based on the path loss between the terminal and the AP is a stable range, and the ideal coverage range will not change with changes in the AP transmit power.

[0157] In the embodiments of the present application, the area where each terminal associated with a certain AP is located can be called the actual coverage of the AP. The actual coverage is not fixed, but is related to the transmit power of the AP. For example, if the transmit power of the AP is high, then terminals that are far away from the AP can also be associated with the AP, and the actual coverage of the AP is larger. On the contrary, if the transmit power of the AP is low, then only terminals that are close to the AP can be associated with the AP, and the actual coverage of the AP is smaller. For example, refer to Fig.13 It can be seen from the dotted box in that if the transmit power of AP2 is greater than the transmit power of AP1, not only STA3 and STA4 belonging to AP2 will be associated with AP2, but STA2 belonging to AP1 will also be associated with AP2.

[0158] It is understandable that if a terminal is associated with an AP that is far away, the AP needs to provide a larger transmit power to ensure that the received signal strength of the terminal meets the communication quality requirements due to the large path loss between the terminal and the AP. This not only leads to higher power consumption of the AP, but also causes greater interference to other APs.

[0159] In an embodiment of the present application, the ideal coverage range of the AP determined by the controller can be used for radio frequency tuning. For example, the controller can adjust the transmit power of the AP based on the ideal coverage range, so that the AP can be associated with the terminal located within its ideal coverage range, but not with the terminal located outside its ideal coverage range, that is, the actual coverage range of the AP can be adjusted to the same range as the ideal coverage range of the AP. Thereby, it can be ensured that the AP can provide network access services to the terminal based on the principle of nearby services, that is, the terminal can be associated with the AP with the smallest path loss. Furthermore, it can be ensured that the AP does not need a very high transmit power to make the received signal strength of the terminal meet the communication quality requirements, that is, the interference caused by excessive power of the AP can be avoided under the premise of ensuring the signal coverage quality of the AP.

[0160] Based on the above step 107, it can be known that the first AP can report the received signal strength detected by the terminal associated with it. Accordingly, when storing the path loss, the controller can count the terminal measurement data of each AP separately with AP as the granularity. Taking the first AP as an example, the terminal measurement data of the first AP may include: the path loss between the first AP and each terminal associated with it, and the path loss between the neighbor AP and each of the above terminals.

[0161] After determining the ideal coverage range of the AP, the controller can also adjust the terminal measurement data of the AP recorded by it based on the ideal coverage range. Taking the first AP as an example, the adjusted terminal measurement data of the first AP may include: the path loss between the first AP and each terminal located within the ideal coverage range of the first AP, and the path loss between the neighboring AP and each of the above terminals.

[0162] For example, if the associated AP associated with a terminal is not its home AP, the controller can delete the path loss between each AP and the terminal from the terminal measurement data of the associated AP (this deletion operation is also called de-stickiness), and add the path loss between each AP and the terminal to the terminal measurement data of the home AP (this addition operation is also called supplementary stickiness).

[0163] Example, reference Fig.13 , assuming that STA2 belonging to AP1 is associated with AP2, the controller can delete the path loss between each AP and STA2 from the terminal measurement data of AP2, and add the path loss between each AP and STA2 to the terminal measurement data of AP1.

[0164] Step 112: The controller identifies whether any one of the first AP and the second AP is a high-hanging AP.

[0165] In the embodiment of the present application, for any AP of the first AP and the second AP, the controller may determine whether the any AP is a high-hanging AP based on the path loss between the any AP and the multiple terminals. A high-hanging AP refers to an AP whose distance to the multiple terminals is greater than a distance threshold, or an AP with obstructions between the multiple terminals. For example, referring to Figure 5 (a), the high-mounted AP may include an AP disposed on a higher roof, or, referring to Figure 5 (b) An AP installed between the roof and the ceiling (or suspended ceiling).

[0166] As a possible implementation, the multiple terminals may refer to terminals within an ideal coverage range of any AP. The controller may determine that any AP is a high-hanging AP when it detects that the path loss between any AP and the terminals within the ideal coverage range of the any AP is greater than a first loss threshold.

[0167] As another possible implementation, the multiple terminals may refer to terminals associated with any AP. The controller may determine that any AP is a high-hanging AP when it detects that the path loss between any AP and each terminal associated with it is greater than a first loss threshold. The first loss threshold may be a fixed value preconfigured in the controller, for example, a fixed value input into the controller based on expert experience or a loss threshold calculated by the controller based on real-time data and / or historical data of the network environment.

[0168] Based on the above two implementation methods, it can be seen that if the path loss between the AP and multiple terminals is large, the controller can determine that the distance between the deployment position of the AP and the distribution plane of the terminal is far, or there is an obstruction between the deployment position of the AP and the distribution plane of the terminal, and then determine that any AP is a high-hanging AP.

[0169] If the controller identifies an AP as a high-hanging AP, it can be determined that the path loss between the AP and the terminal is large. Accordingly, during subsequent radio frequency tuning, the transmit power of the high-hanging AP can be adjusted higher to ensure that the received signal strength of the terminal (which can refer to the terminal associated with the high-hanging AP, or the terminal located within the ideal coverage range of the high-hanging AP) can meet the communication quality requirements.

[0170] Step 113: The controller determines whether there is an obstruction between the first AP and the second AP.

[0171] In the embodiment of the present application, the controller can also determine whether there is an obstruction between the first AP and the second AP based on the network topology between the first AP, the second AP and the target terminal. It is understandable that the obstruction between the APs can also be used as a basis for subsequent radio frequency tuning of the APs to improve the reliability of radio frequency tuning.

[0172] As a possible implementation method, if the controller determines that the path loss between the first AP and the terminal located within the ideal coverage range of the first AP is less than the second loss threshold, the path loss between the second AP and the terminal located within the ideal coverage range of the first AP is less than the second loss threshold, and the third path loss between the first AP and the second AP is greater than the third loss threshold, it can be determined that there is an obstruction between the first AP and the second AP.

[0173] Example, reference Figure 6In (a) to (c), if the controller determines that the path loss between AP1 and a terminal within the ideal coverage range of AP1 is less than a second loss threshold, the path loss between AP2 and a terminal within the ideal coverage range of AP2 is less than the second loss threshold, and the third path loss between AP1 and AP2 is greater than the third loss threshold, then it can be determined that there is an obstruction between AP1 and AP2.

[0174] As another possible implementation method, if the controller determines that the path loss between the first AP and the terminal associated with it is less than a second loss threshold, the path loss between the second AP and the terminal associated with the first AP is less than the second loss threshold, and the third path loss between the first AP and the second AP is greater than the third loss threshold, it can be determined that there is an obstruction between the first AP and the second AP.

[0175] Based on the above two implementations, it can be known that the controller can determine that there is an obstruction between the two APs when it detects that the path loss between each of the two APs and the terminal is small, but the path loss between the two APs is large. It can be understood that the above second loss threshold and the third loss threshold are both fixed values ​​pre-configured in the controller, for example, they can be fixed values ​​input into the controller based on expert experience or the controller can calculate the loss threshold based on real-time data and / or historical data of the network environment. In addition, the second loss threshold and the third loss threshold can be equal or different.

[0176] It can be understood that if the controller determines that the path loss between the first AP and the terminal located within the ideal coverage range of the first AP is less than the second loss threshold, the path loss between the second AP and the terminal located within the ideal coverage range of the first AP is also less than the second loss threshold, and the third path loss between the first AP and the second AP is not greater than the third loss threshold, then it can be determined that there is no obstruction between the first AP and the second AP.

[0177] If the controller determines that the path loss between the first AP and the terminal located within the ideal coverage range of the first AP is less than the second loss threshold, the path loss between the second AP and the terminal located within the ideal coverage range of the first AP is not less than the second loss threshold, and the third path loss between the first AP and the second AP is greater than the third loss threshold, then it can also be determined that there is no obstruction between the first AP and the second AP.

[0178] Step 114: The controller performs radio frequency tuning on at least one of the first AP and the second AP based on the network topology between the first AP, the second AP, and the target terminal.

[0179] The radio frequency tuning may include adjusting the transmit power of the AP and / or adjusting the channel of the AP.

[0180] As a possible example, for any AP among the first AP and the second AP, the controller can adjust the transmission power of any AP based on the path loss between the any AP and the terminal located within the ideal coverage range of the any AP, so that the strength of the signal sent by the any AP detected by the terminal located within the ideal coverage range of the any AP (i.e., the received signal strength of the downlink) is greater than the strength threshold, so as to ensure that the received signal strength of the terminal within the ideal coverage range of the any AP can meet the communication quality requirements. The strength threshold can be a fixed value pre-configured in the controller, and the size of the strength threshold can be determined based on experience, or can be calculated based on real-time data and / or historical data of the network environment. For example, the strength threshold can be -65dBm determined based on experience.

[0181] Based on the above power adjustment method, it can be ensured that all terminals within the ideal coverage range of any AP are associated with the AP, thereby avoiding interference caused by excessive power of the AP while ensuring the signal coverage quality of the AP.

[0182] As another possible example, the controller may allocate a channel of a first frequency to the first AP based on the network topology, and allocate a channel of a second frequency to the second AP. The first frequency and the second frequency may satisfy the following conditions:

[0183] On the one hand, if the path loss between the first AP and the terminal within the ideal coverage range of the second AP is greater than the fourth loss threshold, and the path loss between the second AP and the terminal within the ideal coverage range of the first AP is greater than the fourth loss threshold, the controller can determine that each AP has less interference with the terminal within the ideal coverage range of the other AP, and thus can allocate the same frequency or a channel with a similar frequency to the two APs. Accordingly, the frequency difference between the first frequency and the second frequency can be less than the first frequency threshold, for example, the first frequency can be equal to the second frequency.

[0184] On the other hand, if the path loss between the first AP and the terminal within the ideal coverage range of the second AP is less than the fifth loss threshold, or the path loss between the second AP and the terminal within the ideal coverage range of the first AP is less than the fifth loss threshold, the controller can determine that the AP has a greater interference with the terminal within the ideal coverage range of the other AP, and the frequencies of the channels of the two APs need to be staggered. Accordingly, the frequency difference between the first frequency and the second frequency can be greater than the second frequency threshold.

[0185] On the other hand, if the controller determines based on the above step 113 that there is no obstruction between the first AP and the second AP, and the path loss between the first AP and the second AP is large (for example, greater than the third loss threshold), it can also be determined that each AP has less interference with the terminal within the ideal coverage range of the other AP, so the two APs can be assigned channels with the same frequency or a similar frequency. That is, in this scenario, the frequency difference between the first frequency and the second frequency can also be less than the first frequency threshold.

[0186] It is understandable that the fourth loss threshold, the fifth loss threshold, the first frequency threshold and the second frequency threshold are all fixed values ​​pre-configured in the controller. In addition, the fourth loss threshold may be greater than or equal to the fifth loss threshold, and the first frequency threshold may be less than or equal to the second frequency threshold.

[0187] Based on the above channel allocation method, it can be known that the controller can allocate channels with the same or similar frequencies to the two APs when it is determined that the interference between the downlink signals of the two APs is small, and can allocate channels with different frequencies to the two APs when it is determined that the interference between the downlink signals of the two APs is large to avoid co-channel interference. Since the number of channels that can be allocated in the system is limited, the channel allocation method provided in the embodiment of the present application can ensure that the co-channel interference of the entire system is small.

[0188] Fig.14 This is a flow chart of a method for a controller to generate a terminal portrait provided by an embodiment of the present application, refer to Fig.14 , the method may include:

[0189] Step 115: The controller detects whether the terminal portrait of the target terminal is currently valid.

[0190] In an embodiment of the present application, a terminal portrait of a target terminal may be pre-stored in the controller, and the terminal portrait may be used to indicate whether the target terminal currently has the ability to detect the received signal strength. In addition, in order to ensure the timeliness of the terminal portrait, the terminal portrait has a certain validity period. The controller may re-update the terminal portrait when it is determined that the validity period of the terminal portrait has expired, that is, when it is determined that the terminal portrait is invalid.

[0191] In the embodiment of the present application, if the controller determines that the terminal portrait of the target terminal is invalid or the terminal portrait of the target terminal is not stored, step 116 can be executed; if the controller determines that the terminal portrait of the target terminal is valid, step 122 can be executed.

[0192] Optionally, the controller can detect whether the terminal portrait of the target terminal is currently valid when detecting that the target terminal is online (i.e., when the target terminal establishes an association with the first AP). If the target terminal is a new terminal, i.e., the target terminal associates with the AP connected to the controller for the first time, the terminal portrait of the target terminal is not stored in the controller.

[0193] Step 116: The controller sends a detection instruction to the first AP.

[0194] If the controller determines that the terminal portrait of the target terminal is invalid or the terminal portrait of the target terminal is not stored, the controller may send a detection instruction to the first AP. The detection instruction may be used to instruct the first AP to trigger the target terminal to detect the received signal strength.

[0195] Step 117: The first AP sends a measurement frame to the target terminal.

[0196] After the first AP receives the detection instruction sent by the controller, it can send a measurement frame to the target terminal based on the detection instruction. If the target terminal currently has the ability to detect the received signal strength, the target terminal can feed back a measurement response frame to the first AP after receiving the measurement frame. The measurement response frame includes the received signal strength of the measurement frame detected by the target terminal. If the target terminal currently does not have the ability to detect the received signal strength, the target terminal will not feed back a measurement response frame carrying the received signal strength to the first AP after receiving the measurement frame.

[0197] It is understandable that the target terminal currently does not have the ability to detect the strength of the received signal, which may be caused by the following situations: 1. The target terminal does not support the signal strength detection standard. 2. The target terminal supports the signal strength detection standard, but is currently unable to feedback the measurement response frame due to factors such as the operating status (for example, the screen is often off or in power saving mode). Among them, the signal strength detection standard can be the Institute of Electrical and Electronics Engineers (IEEE) 802.11k standard.

[0198] Step 118: The first AP sends a detection result to the controller based on the received signal strength fed back by the target terminal.

[0199] The first AP may send a detection result to the controller based on the received signal strength fed back by the target terminal, where the detection result is used to indicate whether the first AP has received the received signal strength fed back by the target terminal.

[0200] Step 119: The controller determines a detection success rate of the target terminal based on the detection results sent by the first AP in the first time period.

[0201] The controller can count the detection results sent by the first AP in the first time period to determine the detection success rate of the target terminal. The detection success rate p can satisfy: p = M1 / M0, where M1 is the number of target detection results received by the controller in the first time period, M0 is the total number of detection results received by the controller in the first time period, and the target detection result is used to indicate the received signal strength fed back by the first AP to the target terminal.

[0202] For example, assuming that the first AP sends 200 measurement frames in the first time period, and the target terminal feeds back 180 measurement response frames, the first AP will send 200 detection results to the controller in the first time period, and the 200 detection results include 180 target detection results, that is, M0 = 200, M1 = 180. Accordingly, the controller can calculate the detection success rate p of the target terminal as: p = 180 / 200 = 0.9.

[0203] It is understandable that the first time period may be a time period after the controller sends a detection instruction to the first AP. The duration of the first time period may be a fixed duration preconfigured in the controller, for example, the first time period may be 1 minute or 2 minutes.

[0204] As a possible example, in order to ensure the accuracy of the determined detection success rate, the controller may calculate the detection success rate of the target terminal in multiple first time periods, and the controller may perform the following step 121 after determining that the detection success rate tends to be stable. The detection success rate tends to be stable may mean that the change in the detection success rate of two adjacent first time periods is less than a threshold value, such as 5%.

[0205] As another possible example, in order to improve the efficiency of determining the detection success rate, the controller can also directly determine that the detection success rate of the target terminal is 0 when it detects that the number of consecutively received failed detection results is greater than or equal to the number threshold. The failed detection result is used to indicate that the first AP has not received the received signal strength fed back by the target terminal. For example, assuming that the number threshold is 100, if the first AP does not receive the measurement response frame fed back by the target terminal after sending 100 measurement frames in succession, the first AP will send 100 failed detection results to the controller in succession. The controller can then determine that the detection success rate of the target terminal is 0.

[0206] Step 120: The controller processes the detection success rates of multiple terminals to obtain a success rate threshold.

[0207] In an embodiment of the present application, the controller may further process the detection success rates of the multiple terminals acquired in a third period to determine a success rate threshold. The third period may be a period before the first period. Furthermore, the third period may partially overlap with the first period, or may not overlap, which is not limited in the embodiment of the present application.

[0208] As an optional implementation manner, the controller may use a box plot algorithm to process the detection success rates of the multiple terminals determined in the third time period to obtain the success rate threshold.

[0209] The principle of the box plot algorithm is as follows: among the large number of observations obtained, the observations that are less than QL-1.5IQR or greater than QU+1.5IQR are determined as outliers. Among them, QL is the lower quartile, which means that one-quarter of all observations are smaller than QL. QU is the upper quartile, which means that one-quarter of all observations are larger than QU. IQR is the interquartile range, which is the difference between the upper quartile QU and the lower quartile QL, that is, IQR = QU-QL.

[0210] In an embodiment of the present application, the detection success rate of the terminal obtained by the controller is the observed value. The controller can use a box plot algorithm to process a large number of acquired detection success rates, and can use QL-1.5IQR as the success rate threshold.

[0211] Based on the principle description of the above-mentioned box plot algorithm, it can be known that the box plot algorithm can truly and intuitively show the distribution of observations, and there will be no restrictive requirements on the observations (for example, it does not require the observations to obey the normal distribution or approximately obey the normal distribution). The standard for judging outliers by the box plot algorithm is based on quartiles and interquartile ranges. Since the quartiles give some indication of the center, spread, and shape of the distribution of observations, they have a certain robustness, that is, 25% of the observations can become arbitrarily far without greatly disturbing the quartiles, so outliers usually cannot exert an impact on this standard. In view of this, the result of the box plot identifying outliers is relatively objective, so the embodiment of the present application adopts the box plot algorithm to determine the success rate threshold to ensure the reliability of the success rate threshold.

[0212] As another optional implementation manner, the controller may also use the 3σ principle to process the detection success rates of multiple terminals to obtain a success rate threshold.

[0213] It is understandable that the controller may also directly adopt a pre-configured fixed value as the success rate threshold.

[0214] Step 121: The controller generates a terminal portrait of the target terminal based on the detection success rate of the target terminal.

[0215] The terminal portrait of the target terminal can be used to indicate whether the target terminal has the ability to detect the received signal strength in the second time period after the current moment, that is, the terminal portrait is valid in the second time period after the current moment.

[0216] Wherein, if the detection success rate of the target terminal is greater than or equal to the success rate threshold, the controller can determine that the target terminal has the ability to detect the received signal strength in a second time period after the current moment. If the detection success rate of the target terminal is less than the success rate threshold, the controller can determine that the target terminal does not have the ability to detect the received signal strength in the second time period after the current moment.

[0217] It can be understood that the duration of the second period can be a fixed duration preconfigured in the controller, for example, the second duration can be three months.

[0218] Step 122: The controller determines whether the target terminal currently has the ability to detect the received signal strength based on the terminal portrait of the target terminal.

[0219] If the controller determines that the terminal portrait of the target terminal is valid, it can determine whether the target terminal currently has the ability to detect the strength of the received signal based on the terminal portrait of the target terminal. If the controller determines that the target terminal does not currently have the ability to detect the strength of the received signal based on the terminal portrait, the operation can be terminated, that is, the controller does not need to start the measurement of the target terminal. If the controller determines that the target terminal currently has the ability to detect the strength of the received signal based on the terminal portrait, the above step 101 can be executed. That is, when the controller determines that the target terminal currently has the ability to detect the strength of the received signal, it can send a strength measurement instruction for the target terminal to the first AP associated with the target terminal. In this way, invalid measurements caused by the controller sending a strength measurement instruction to the first AP when the target terminal does not have the ability to detect the strength of the received signal can be avoided.

[0220] For example, the terminal portraits of each terminal stored in the controller can be as shown in Table 2. If the target terminal is a terminal with a MAC address of 00:11:22:33:44:55, and the current time is 2020-11-30, the controller can determine that the target terminal currently has the ability to detect the received signal strength based on the terminal portrait shown in Table 2, and can perform the above step 101. If the target terminal is a terminal with a MAC address of aa:bb:cc:dd:ee:ff, the controller can determine that the target terminal currently does not have the ability to detect the received signal strength based on the terminal portrait shown in Table 2, and can end the operation.

[0221] Table 2

[0222] MAC address of the terminal Terminal image Expiration time 00:11:22:33:44:55 Capable of detecting received signal strength 2020-12-1 aa:bb:cc:dd:ee:ff No detection capability for received signal strength 2020-12-1 33:44:55:66:77:88 The image has expired 2020-11-2

[0223] Assuming that the signal strength detection standard is the IEEE 802.11k standard, about 60%-70% of the terminals in the current network support the 802.11k standard, and the remaining 30%-40% of the terminals do not support the 802.11k standard. The method provided in the embodiment of the present application starts the measurement after determining that the target terminal has the detection capability of the received signal strength, which can theoretically reduce the air interface overhead of the downlink measurement by at least 30%.

[0224] It is understandable that the order of the steps of the method provided in the embodiment of the present application can be appropriately adjusted, and the steps can also be increased or decreased accordingly according to the situation. For example, step 103 can be performed before step 102, and step 108 can be performed before step 107. Step 110 and step 111 can be deleted according to the situation, and any step in step 112 to step 114 can be deleted according to the situation, and the execution order of each step in step 112 to step 114 can be adjusted according to the situation. Any technician familiar with the technical field can easily think of the method of change within the technical scope disclosed in this application, which should be covered within the scope of protection of this application, so it will not be repeated.

[0225] It can also be understood that the above embodiment is explained by taking the path loss between the AP and the terminal as the path loss of the downlink as an example. Of course, the path loss can also be the path loss of the uplink between the AP and the terminal, and the path loss of the uplink can be obtained based on the transmission power of the terminal and the strength of the signal sent by the terminal detected by the AP (for example, the RSSI of the uplink). Among them, if the second AP is required to detect the strength of the signal sent by the target terminal, the second AP can switch its working channel to the target channel (i.e., the channel used when the first AP is associated with the target terminal) to receive the signal sent by the target terminal and detect the strength of the received signal.

[0226] In summary, the embodiment of the present application provides a method for identifying a network topology, and the network topology determined by the controller includes not only the path loss between two APs, but also the path loss between each AP and the terminal, that is, the network topology is a 3D network topology. Since in the 3D network topology, the path loss between the AP and the terminal can not only accurately reflect the signal transmission performance of the link between the AP and the terminal, but also can accurately reflect the degree of interference between downlink signals sent by different APs, it can ensure that the network topology determined by the controller has a high reliability. Furthermore, it can ensure that the reliability of AP management and control (such as RF tuning) based on the network topology is high.

[0227] In addition, the method provided in the embodiment of the present application also includes at least the following beneficial effects:

[0228] 1. The controller can identify non-ideal deployment scenarios such as high-hanging APs and obstructions between APs. Therefore, it can ensure that after RF tuning based on the identified deployment scenarios, it can provide terminals with better signal quality, lower interference, and better service experience.

[0229] 2. The controller can determine the ideal coverage range of the AP based on the path loss between the AP and the terminal, and can perform power optimization based on the ideal coverage range. In this way, interference caused by excessive power of the AP can be avoided while ensuring the signal coverage quality of the AP.

[0230] 3. The controller allocates channels to APs based on 3D network topology, which can effectively avoid co-channel interference.

[0231] 4. The path loss between the AP and the terminal in the 3D network topology determined by the controller may be the path loss of the downlink. Since the path loss of the downlink is an important factor affecting the terminal service experience, performing RF tuning based on the path loss of the downlink can effectively improve the terminal service experience.

[0232] 5. The controller can measure the terminals that currently have the ability to detect signal strength based on the terminal portrait, thereby avoiding invalid measurements and wasting network resources.

[0233] Fig.15 is a schematic diagram of a controller provided in an embodiment of the present application. The controller can be applied to Figure 1 or Figure 2 The system shown in the figure can be used to implement the network topology identification method provided by the above method embodiment. Fig.15 , the controller comprises:

[0234] The first determination module 201 is used to determine the network topology between the first access point AP, the second AP and the target terminal. The target terminal is associated with the first AP, the second AP is a neighbor AP of the first AP, and the network topology includes: a first path loss, a second path loss and a third path loss, the first path loss is the path loss between the first AP and the target terminal, the second path loss is the path loss between the second AP and the target terminal, and the third path loss is the path loss between the first AP and the second AP.

[0235] The functional implementation of the first determination module 201 may refer to the relevant description of step 109 in the above method embodiment.

[0236] Optionally, the first determination module 201 can also be used to determine the AP with the smallest path loss between the first AP and multiple neighboring APs of the first AP and the target terminal as the home AP to which the target terminal belongs; and determine the ideal coverage range of the home AP based on the terminal belonging to the home AP, and the ideal coverage range of the home AP is used for RF tuning.

[0237] The implementation of the functions of the first determining module 201 may also refer to the related descriptions of step 110 and step 111 in the above method embodiment.

[0238] Optionally, the first determination module 201 can also be used to: for any AP between the first AP and the second AP, determine whether any AP is a high-hanging AP based on the path loss between the any AP and multiple terminals. The high-hanging AP refers to an AP whose distance from the multiple terminals is greater than a distance threshold, or an AP where there are obstructions between the AP and the multiple terminals.

[0239] The functional implementation of the first determining module 201 may also refer to the relevant description of step 112 in the above method embodiment.

[0240] Optionally, the first determination module 201 may be configured to: determine that any AP is a high-hanging AP if a path loss between the any AP and a terminal located within an ideal coverage range of the any AP is greater than a first loss threshold.

[0241] Optionally, the first determination module 201 can also be used for: if the path loss between the first AP and the terminal located within the ideal coverage range of the first AP is less than a second loss threshold, the path loss between the second AP and the terminal located within the ideal coverage range of the first AP is less than the second loss threshold, and the third path loss between the first AP and the second AP is greater than a third loss threshold, then it is determined that there is an obstruction between the first AP and the second AP.

[0242] The function implementation of the first determination module 201 may also refer to the related description of step 113 in the above method embodiment.

[0243] Alternatively, if Fig.15 As shown, the controller may also include:

[0244] The tuning module 202 is used to perform radio frequency tuning on at least one of the first AP and the second AP based on the network topology between the first AP, the second AP and the target terminal. The function of the tuning module 202 can be realized by referring to the relevant description of step 114 in the above method embodiment.

[0245] Alternatively, if Fig.16 As shown, the controller may also include:

[0246] The power adjustment module 203 is used to adjust the transmission power of any AP among the first AP and the second AP based on the path loss between the any AP and the terminal located within the ideal coverage range of the any AP, so that the strength of the signal sent by the any AP detected by the terminal located within the ideal coverage range of the any AP is greater than the strength threshold.

[0247] The function implementation of the power regulation module 203 may refer to the related description of step 114 in the above method embodiment.

[0248] Alternatively, if Fig.16 As shown, the controller may also include:

[0249] The channel allocation module 204 is configured to allocate a channel of a first frequency to the first AP and allocate a channel of a second frequency to the second AP. If the path loss between the first AP and a terminal located within an ideal coverage range of the second AP is greater than a fourth loss threshold, and the path loss between the second AP and a terminal located within an ideal coverage range of the first AP is greater than the fourth loss threshold, then the frequency difference between the first frequency and the second frequency is less than the first frequency threshold;

[0250] If the path loss between the first AP and the terminal located within the ideal coverage range of the second AP is less than the fifth loss threshold, or the path loss between the second AP and the terminal located within the ideal coverage range of the first AP is less than the fifth loss threshold, then the frequency difference between the first frequency and the second frequency is greater than the second frequency threshold; the fourth loss threshold is greater than or equal to the fifth loss threshold, and the first frequency threshold is less than or equal to the second frequency threshold.

[0251] The function implementation of the channel allocation module 204 may also refer to the related description of step 114 in the above method embodiment.

[0252] It can be understood that the power regulation module 203 and the channel allocation module 204 can both be submodules in the tuning module 202 , that is, the tuning module 202 can implement the functions of the power regulation module 203 and the channel allocation module 204 .

[0253] Alternatively, if Fig.15 and Fig.16 As shown, the controller may also include:

[0254] The receiving module 205 is used to receive a first received signal strength and a second received signal strength sent by the first AP, and the first received signal strength and the second received signal strength are both sent by the target terminal to the first AP. The first received signal strength is the strength of a first measurement frame sent by the first AP detected by the target terminal, the first measurement frame carries the BSSID of the first AP, and the first received signal strength is used to determine the first path loss; the second received signal strength is the strength of a second measurement frame sent by the second AP detected by the target terminal, the second measurement frame carries the BSSID of the first AP, and the second received signal strength is used to determine the second path loss.

[0255] The functional implementation of the receiving module 205 may refer to the related description of step 107 in the above method embodiment.

[0256] Alternatively, if Fig.15 and Fig.16 As shown, the controller may also include:

[0257] The sending module 206 is used to send a detection instruction to the first AP before the receiving module 205 receives the first received signal strength and the second received signal strength sent by the first AP. The detection instruction is used to instruct the first AP to trigger the target terminal to detect the received signal strength. The function of the sending module 206 can refer to the relevant description of step 116 in the above method embodiment.

[0258] The second determination module 207 is used to determine the detection success rate of the target terminal based on the detection result sent by the first AP in the first time period, and if the detection success rate is greater than or equal to the success rate threshold, determine that the target terminal has the detection capability of receiving signal strength in a second time period after the current moment, wherein the detection result is used to indicate whether the first AP has received the received signal strength fed back by the target terminal; the detection success rate is the ratio of the number of target detection results received in the first time period to the total number of detection results received in the first time period, and the target detection result is used to indicate the received signal strength fed back by the first AP to the target terminal.

[0259] The functional implementation of the second determination module 207 may refer to the related descriptions of step 118, step 119 and step 121 in the above method embodiment.

[0260] The sending module 206 can also be used to send a strength measurement instruction for the target terminal to the first AP based on the target terminal having the ability to detect the received signal strength, and the strength measurement instruction is used to instruct the first AP to obtain the first received signal strength and the second received signal strength.

[0261] The function implementation of the sending module 206 may also refer to the related description of step 101 in the above method embodiment.

[0262] Alternatively, if Fig.15 and Fig.16 As shown, the controller may also include:

[0263] The processing module 208 is used to process the detection success rates of the multiple terminals determined in the third period using a box plot algorithm to obtain the success rate threshold. The function of the processing module 208 can also refer to the relevant description of step 120 in the above method embodiment.

[0264] Optionally, the first AP has multiple neighbor APs including the second AP. After the multiple neighbor APs are sorted in order from small to large according to the path loss between them and the first AP, the arrangement number of the second AP is less than or equal to N, and N is a positive integer less than or equal to the total number of the multiple neighbor APs.

[0265] In summary, an embodiment of the present application provides a controller, and the network topology determined by the controller includes not only the path loss between two APs, but also the path loss between each AP and the terminal, that is, the network topology is a 3D network topology. Since in the 3D network topology, the path loss between the AP and the terminal can not only accurately reflect the signal transmission performance of the link between the AP and the terminal, but also can accurately reflect the degree of interference between downlink signals sent by different APs, it can ensure that the reliability of the network topology determined by the controller is high. Furthermore, it can ensure that the reliability of AP management and control (such as RF tuning) based on the network topology is high.

[0266] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the controller and each module described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0267] It should be understood that the controller provided in the embodiment of the present application can be implemented by an application-specific integrated circuit (ASIC) or a programmable logic device (PLD), and the PLD can be a complex programmable logical device (CPLD), a field-programmable gate array (FPGA), a generic array logic (GAL) or any combination thereof. Alternatively, the network topology recognition method provided in the above method embodiment can also be implemented by software. When the network topology recognition method provided in the above method embodiment is implemented by software, each module in the above controller can also be a software module.

[0268] Fig.17 is a schematic diagram of the structure of another controller provided in an embodiment of the present application, and the controller can be applied to Figure 1 or Figure 2 In the system shown. Fig.17 , the controller may include: a processor 301, a memory 302, a network interface 303 and a bus 304. The bus 304 is used to connect the processor 301, the memory 302 and the network interface 303. The network interface 303 (which may be wired or wireless) can be used to achieve communication with other devices. The memory 302 stores a computer program 3021, which is used to implement various application functions.

[0269] It should be understood that in the embodiment of the present application, the processor 301 may be a CPU, and the processor 301 may also be other general-purpose processors, digital signal processors (digital signal processing, DSP), application-specific integrated circuits (application-specific integrated circuits, ASIC), field-programmable gate arrays (field-programmable gate arrays, FPGA), generic array logic (generic array logic, GAL) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc., or any combination of the above processors. The general-purpose processor may be a microprocessor or any conventional processor, etc.

[0270] The memory 302 may include a volatile memory, a non-volatile memory, or a combination thereof. The non-volatile memory may include a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), a flash memory, or any combination thereof. The volatile memory may include a random access memory (RAM), such as a static random access memory (SRAM), a dynamic random access memory (DRAM), a synchronous dynamic random access memory (SDRAM), a double data rate synchronous dynamic random access memory (DDR SDRAM), an enhanced synchronous dynamic random access memory (ESDRAM), a synchronous link dynamic random access memory (SLDRAM), a direct rambus RAM (DR RAM), or any combination thereof.

[0271] In addition to the data bus, the bus 304 may also include a power bus, a control bus, a status signal bus, etc. However, for the sake of clarity, various buses are labeled as the bus 304 in the figure.

[0272] The processor 301 may be configured to execute the computer program 3021 stored in the memory 302 to implement the steps performed by the controller in the above method embodiment.

[0273] Fig.18 is a schematic diagram of the structure of another controller provided in an embodiment of the present application, and the controller can be applied to Figure 1 or Figure 2 In the system shown. Fig.18 As shown, the controller includes a main control board 401 and an interface board 402 .

[0274] The main control board 401 is also called a main processing unit (MPU) or a route processor card. The main control board 401 is used to control and manage various components in the controller, including functions such as route calculation, device management, device maintenance, and protocol processing. The main control board 401 includes: a central processing unit 4011 and a memory 4012.

[0275] The interface board 402 is also called a line processing unit (LPU), a line card or a service board. The interface board 402 is used to provide various service interfaces and realize the forwarding of data packets. The service interface includes but is not limited to an Ethernet interface, a packet over SONET / SDH (POS) interface based on SONET / SDH, etc. SONET refers to a synchronous optical network, and SDH refers to a synchronous digital hierarchy. The Ethernet interface is, for example, a flexible Ethernet service interface (FlexE Clients). The interface board 402 includes: a central processing unit 4021, a network processor 4022, a forwarding table entry memory 4024 and a physical interface card (PIC) 4023.

[0276] The central processor 4021 on the interface board 402 is used to control and manage the interface board 402 and communicate with the central processor 4011 on the main control board 401 .

[0277] The network processor 4022 is used to implement the forwarding processing of the message. The network processor 4022 can be in the form of a forwarding chip. The forwarding chip can be a network processor (NP). In some embodiments, the forwarding chip can be implemented by an application-specific integrated circuit (ASIC) or a field programmable gate array (FPGA). Specifically, the network processor 4022 is used to forward the received message based on the forwarding table stored in the forwarding table entry memory 4024. If the destination address of the message is the address of the controller, the message is sent to the CPU (such as the central processor 4021) for processing; if the destination address of the message is not the address of the controller, the next hop and the output interface corresponding to the destination address are found from the forwarding table according to the destination address, and the message is forwarded to the output interface corresponding to the destination address. Among them, the processing of the uplink message may include: processing of the message input interface, forwarding table search; the processing of the downlink message may include: forwarding table search, etc. In some embodiments, the central processor can also perform the function of the forwarding chip, such as implementing software forwarding based on a general-purpose CPU, so that the forwarding chip is not required in the interface board.

[0278] The physical interface card 4023 is used to implement the connection function of the physical layer, and the original traffic enters the interface board 402 from it, and the processed message is sent from the physical interface card 4023. The physical interface card 4023 is also called a daughter card, which can be installed on the interface board 402, and is responsible for converting the optical signal into a message and forwarding the message to the network processor 4022 for processing after checking the legitimacy of the message. In some embodiments, the central processor 4021 can also perform the functions of the network processor 4022, such as realizing software forwarding based on a general-purpose CPU, so that the network processor 4022 is not required in the physical interface card 4023.

[0279] Optionally, the controller includes multiple interface boards, for example, the controller also includes an interface board 403, and the interface board 403 includes: a central processing unit 4031, a network processor 4032, a forwarding table entry memory 4034, and a physical interface card 4033. The functions and implementation methods of the components in the interface board 403 are the same or similar to those of the interface board 402, and are not described in detail here.

[0280] Optionally, the controller further includes a switching fabric board 404. The switching fabric board 404 may also be referred to as a switch fabric unit (SFU). When the network management device has multiple interface boards, the switching fabric board 404 is used to complete data exchange between the interface boards. For example, the interface board 402 and the interface board 403 may communicate via the switching fabric board 404.

[0281] The main control board 401 is coupled to the interface board. For example, the main control board 401, the interface board 402, the interface board 403, and the switching network board 404 are connected to the system backplane through a system bus to achieve intercommunication. In a possible implementation, an inter-process communication (IPC) channel is established between the main control board 401 and the interface board 402 and the interface board 403, and the main control board 401 and the interface board 402 and the interface board 403 communicate through the IPC channel.

[0282] Logically, the controller includes a control plane and a forwarding plane. The control plane includes a main control board 401 and a central processing unit 4011. The forwarding plane includes various components for performing forwarding, such as a forwarding table entry memory 4024, a physical interface card 4023, and a network processor 4022. The control plane performs functions such as a router, generating a forwarding table, processing signaling and protocol messages, and configuring and maintaining the status of network devices. The control plane sends the generated forwarding table to the forwarding plane. On the forwarding plane, the network processor 4022 forwards the message received by the physical interface card 4023 based on the forwarding table sent by the control plane. The forwarding table sent by the control plane can be stored in the forwarding table entry memory 4024. In some embodiments, the control plane and the forwarding plane can be completely separated and not on the same network device.

[0283] It is worth noting that there may be one or more main control boards, and when there are multiple boards, they may include a primary main control board and a backup main control board. There may be one or more interface boards. The stronger the data processing capability of the network management device, the more interface boards are provided. There may also be one or more physical interface cards on the interface board. There may be no switching network board, or there may be one or more switching network boards. When there are multiple switching network boards, they can jointly realize load sharing and redundant backup. In a centralized forwarding architecture, the network management device may not need a switching network board, and the interface board is responsible for the processing function of the service data of the entire system. In a distributed forwarding architecture, the network management device may have at least one switching network board, and the switching network board is used to realize data exchange between multiple interface boards, providing large-capacity data exchange and processing capabilities. Therefore, the data access and processing capabilities of the network management device with a distributed architecture are greater than those of the network management device with a centralized architecture. Optionally, the network management device may be in the form of only one board, that is, without a switching network board, and the functions of the interface board and the main control board are integrated on the board. In this case, the central processor on the interface board and the central processor on the main control board can be combined into one central processor on the board to perform the functions of the two superimposed. This form of network management device has low data exchange and processing capabilities (for example, low-end switches or routers and other network devices). Which architecture to use depends on the specific networking deployment scenario, and no limitation is made here.

[0284] An embodiment of the present application also provides a computer-readable storage medium, in which instructions are stored. The instructions are executed by a processor to implement the network topology identification method provided by the above method embodiment.

[0285] An embodiment of the present application also provides a computer program product comprising instructions. When the computer program product is run on a computer, the computer is enabled to execute the network topology identification method provided in the above method embodiment.

[0286] The present application also provides a wireless communication system. Figure 1 and Figure 2 As shown, the system includes: a controller 01, and a plurality of APs 02 connected to the controller 01. The controller 01 may be Figures 15 to 17 The controller shown in any of the figures. For example, the controller 01 may be an AC.

[0287] The above embodiments can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software or firmware, the above embodiments can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded or executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from a website mobile terminal, computer, server or data center to another website mobile terminal, computer, server or data center by wired (e.g., coaxial cable, optical fiber, twisted pair) or wireless (e.g., infrared, wireless, microwave, etc.) mode. The computer-readable storage medium can be any medium that a computer can access or a data storage device such as a server or data center containing one or more media sets. The medium can be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., an optical disk), or a semiconductor medium. The semiconductor medium can be a solid state drive (SSD).

[0288] In this application, the term "at least one" means one or more, and the term "plurality" means two or more. The terms "system" and "network" are often used interchangeably. The "and / or" mentioned in this article indicates that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the objects before and after are in an "or" relationship.

[0289] The above description is only an optional embodiment of the present application and is not intended to limit the present application. The protection scope of the present application shall be subject to the claims.

Claims

1. A method for identifying network topology, characterized in that: The method comprises: Determine a network topology between a first access point AP, a second AP, and a target terminal, wherein the target terminal is associated with the first AP, and the second AP is a neighbor AP of the first AP, and the network topology includes: a first path loss, a second path loss, and a third path loss, wherein the first path loss is a path loss between the first AP and the target terminal, the second path loss is a path loss between the second AP and the target terminal, and the third path loss is a path loss between the first AP and the second AP; the second path loss is determined based on a second received signal strength, wherein the second received signal strength is a strength of a second measurement frame sent by the second AP detected by the target terminal, and the second measurement frame carries a basic service set identifier BSSID of the first AP; Based on the network topology between the first AP, the second AP and the target terminal, radio frequency tuning is performed on at least one of the first AP and the second AP, and the radio frequency tuning includes adjusting at least one parameter in the AP's transmit power and channel.

2. The method according to claim 1, characterized in that The method further comprises: Determine the AP with the smallest path loss between the first AP and the target terminal among the plurality of neighboring APs of the first AP as the home AP to which the target terminal belongs; An ideal coverage range of the home AP is determined based on terminals belonging to the home AP, and the ideal coverage range of the home AP is used for radio frequency tuning.

3. The method according to claim 1 or 2, characterized in that: The method further comprises: For any AP among the first AP and the second AP, determine whether any AP is a high-hanging AP based on the path loss between any AP and multiple terminals. The high-hanging AP refers to an AP whose distance to the multiple terminals is greater than a distance threshold, or an AP with obstructions between the AP and the multiple terminals.

4. The method according to claim 2, characterized in that: The method further comprises: For any AP of the first AP and the second AP, determine whether the any AP is a high-hanging AP based on a path loss between the any AP and a plurality of terminals, where the high-hanging AP refers to an AP whose distance to the plurality of terminals is greater than a distance threshold, or an AP where there are obstructions to the plurality of terminals; The multiple terminals are terminals located within an ideal coverage range of any of the APs; and determining whether any of the APs is a high-hanging AP based on a path loss between the any of the APs and the multiple terminals includes: If the path loss between any AP and a terminal located within an ideal coverage range of any AP is greater than a first loss threshold, it is determined that any AP is a high-hanging AP.

5. The method according to claim 2 or 4, characterized in that: The method further comprises: If the path loss between the first AP and the terminal located within the ideal coverage range of the first AP is less than the second loss threshold, the path loss between the second AP and the terminal located within the ideal coverage range of the first AP is less than the second loss threshold, and the third path loss between the first AP and the second AP is greater than the third loss threshold, it is determined that there is an obstruction between the first AP and the second AP.

6. The method according to claim 2 or 4, characterized in that: The method further comprises: For any AP among the first AP and the second AP, based on the path loss between the any AP and a terminal located within an ideal coverage range of the any AP, the transmission power of the any AP is adjusted so that the strength of the signal sent by the any AP detected by the terminal located within the ideal coverage range of the any AP is greater than a strength threshold.

7. The method according to claim 2 or 4, characterized in that: The method further comprises: Allocate a channel of a first frequency to the first AP, and allocate a channel of a second frequency to the second AP; If the path loss between the first AP and the terminal located within the ideal coverage range of the second AP is greater than a fourth loss threshold, and the path loss between the second AP and the terminal located within the ideal coverage range of the first AP is greater than the fourth loss threshold, then the frequency difference between the first frequency and the second frequency is less than the first frequency threshold; If the path loss between the first AP and the terminal located within the ideal coverage range of the second AP is less than a fifth loss threshold, or the path loss between the second AP and the terminal located within the ideal coverage range of the first AP is less than the fifth loss threshold, then the frequency difference between the first frequency and the second frequency is greater than the second frequency threshold; The fourth loss threshold is greater than or equal to the fifth loss threshold, and the first frequency threshold is less than or equal to the second frequency threshold.

8. The method according to claim 1, 2 or 4, characterized in that: The method further comprises: receiving a first received signal strength and a second received signal strength sent by the first AP, where the first received signal strength and the second received signal strength are both sent by the target terminal to the first AP; The first received signal strength is the strength of a first measurement frame sent by the first AP detected by the target terminal, the first measurement frame carries the BSSID of the first AP, and the first received signal strength is used to determine the first path loss.

9. The method according to claim 8, characterized in that Before receiving the first received signal strength and the second received signal strength sent by the first AP, the method further includes: Sending a detection instruction to the first AP, where the detection instruction is used to instruct the first AP to trigger the target terminal to perform a received signal strength detection; Determine a detection success rate of the target terminal based on a detection result sent by the first AP in a first time period, wherein the detection result is used to indicate whether the first AP receives a received signal strength fed back by the target terminal; If the detection success rate is greater than or equal to the success rate threshold, determining that the target terminal has the ability to detect the received signal strength within a second time period after the current moment; Based on the target terminal having a received signal strength detection capability, sending a strength measurement instruction for the target terminal to the first AP, where the strength measurement instruction is used to instruct the first AP to obtain the first received signal strength and the second received signal strength; Among them, the detection success rate is the ratio of the number of target detection results received in the first time period to the total number of detection results received in the first time period, and the target detection result is used to indicate the received signal strength fed back by the first AP from the target terminal.

10. The method according to claim 9, characterized in that The method further comprises: The detection success rates of the multiple terminals determined in the third time period are processed using a box plot algorithm to obtain the success rate threshold.

11. The method according to claim 1 or 2 or 4 or 9 or 10, characterized in that: The first AP has multiple neighbor APs including the second AP. After the multiple neighbor APs are sorted in order from small to large according to the path loss between them and the first AP, the arrangement number of the second AP is less than or equal to N, and N is a positive integer less than or equal to the total number of the multiple neighbor APs.

12. A controller, characterized in that: The controller comprises: A first determination module is used to determine a network topology between a first access point AP, a second AP, and a target terminal, wherein the target terminal is associated with the first AP, and the second AP is a neighbor AP of the first AP, and the network topology includes: a first path loss, a second path loss, and a third path loss, wherein the first path loss is a path loss between the first AP and the target terminal, the second path loss is a path loss between the second AP and the target terminal, and the third path loss is a path loss between the first AP and the second AP; the second path loss is determined based on a second received signal strength, wherein the second received signal strength is a strength of a second measurement frame sent by the second AP detected by the target terminal, and the second measurement frame carries a basic service set identifier BSSID of the first AP; Based on the network topology between the first AP, the second AP and the target terminal, radio frequency tuning is performed on at least one of the first AP and the second AP.

13. The controller according to claim 12, characterized in that: The first determining module is further used for: Determine the AP with the smallest path loss between the first AP and the target terminal among the plurality of neighboring APs of the first AP as the home AP to which the target terminal belongs; An ideal coverage range of the home AP is determined based on terminals belonging to the home AP, and the ideal coverage range of the home AP is used for radio frequency tuning.

14. The controller according to claim 12 or 13, characterized in that: The first determining module is further used for: For any AP among the first AP and the second AP, determine whether any AP is a high-hanging AP based on the path loss between any AP and multiple terminals. The high-hanging AP refers to an AP whose distance to the multiple terminals is greater than a distance threshold, or an AP with obstructions between the AP and the multiple terminals.

15. The controller according to claim 13, characterized in that: The first determining module is further used for: For any AP of the first AP and the second AP, determine whether the any AP is a high-hanging AP based on a path loss between the any AP and a plurality of terminals, where the high-hanging AP refers to an AP whose distance to the plurality of terminals is greater than a distance threshold, or an AP where there are obstructions to the plurality of terminals; The multiple terminals are terminals located within an ideal coverage range of any of the APs; and determining whether any of the APs is a high-hanging AP based on a path loss between the any of the APs and the multiple terminals includes: If the path loss between any AP and a terminal located within an ideal coverage range of any AP is greater than a first loss threshold, it is determined that any AP is a high-hanging AP.

16. The controller according to claim 13 or 15, characterized in that: The first determining module is further used for: If the path loss between the first AP and the terminal located within the ideal coverage range of the first AP is less than the second loss threshold, the path loss between the second AP and the terminal located within the ideal coverage range of the first AP is less than the second loss threshold, and the third path loss between the first AP and the second AP is greater than the third loss threshold, it is determined that there is an obstruction between the first AP and the second AP.

17. The controller according to claim 13 or 15, characterized in that: The controller further comprises: A power adjustment module is used to adjust the transmission power of any AP among the first AP and the second AP based on the path loss between the any AP and a terminal located within the ideal coverage range of the any AP, so that the strength of the signal sent by the any AP detected by the terminal located within the ideal coverage range of the any AP is greater than a strength threshold.

18. The controller according to claim 12, 13 or 15, characterized in that: The controller further comprises: a channel allocation module, configured to allocate a channel of a first frequency to the first AP and allocate a channel of a second frequency to the second AP; If the path loss between the first AP and the terminal located within the ideal coverage range of the second AP is greater than a fourth loss threshold, and the path loss between the second AP and the terminal located within the ideal coverage range of the first AP is greater than the fourth loss threshold, then the frequency difference between the first frequency and the second frequency is less than the first frequency threshold; If the path loss between the first AP and the terminal located within the ideal coverage range of the second AP is less than a fifth loss threshold, or the path loss between the second AP and the terminal located within the ideal coverage range of the first AP is less than the fifth loss threshold, then the frequency difference between the first frequency and the second frequency is greater than the second frequency threshold; The fourth loss threshold is greater than or equal to the fifth loss threshold, and the first frequency threshold is less than or equal to the second frequency threshold.

19. The controller according to claim 12, 13 or 15, characterized in that: The controller further comprises: A receiving module, configured to receive a first received signal strength and a second received signal strength sent by the first AP, where the first received signal strength and the second received signal strength are both sent by the target terminal to the first AP; The first received signal strength is the strength of a first measurement frame sent by the first AP detected by the target terminal, the first measurement frame carries the BSSID of the first AP, and the first received signal strength is used to determine the first path loss.

20. The controller according to claim 19, characterized in that The controller further comprises: a sending module, configured to send a detection instruction to the first AP before the receiving module receives the first received signal strength and the second received signal strength sent by the first AP, wherein the detection instruction is used to instruct the first AP to trigger the target terminal to perform a received signal strength detection; a second determination module, configured to determine a detection success rate of the target terminal based on a detection result sent by the first AP in a first time period, and if the detection success rate is greater than or equal to a success rate threshold, determine that the target terminal has a detection capability of receiving signal strength in a second time period after a current moment, wherein the detection result is used to indicate whether the first AP has received the received signal strength fed back by the target terminal; The sending module is further used to send a strength measurement instruction for the target terminal to the first AP based on the target terminal having a received signal strength detection capability, wherein the strength measurement instruction is used to instruct the first AP to obtain the first received signal strength and the second received signal strength; Among them, the detection success rate is the ratio of the number of target detection results received in the first time period to the total number of detection results received in the first time period, and the target detection result is used to indicate the received signal strength fed back by the first AP from the target terminal.

21. The controller according to claim 20, characterized in that The controller further comprises: The processing module is used to process the detection success rates of the multiple terminals determined in the third time period by using a box plot algorithm to obtain the success rate threshold.

22. The controller according to claim 12 or 13 or 15 or 20 or 21, characterized in that: The first AP has multiple neighbor APs including the second AP. After the multiple neighbor APs are sorted in order from small to large according to the path loss between them and the first AP, the arrangement number of the second AP is less than or equal to N, and N is a positive integer less than or equal to the total number of the multiple neighbor APs.

23. A controller, characterized in that: The controller includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, and the processor implements the network topology identification method as described in any one of claims 1 to 11 when executing the computer program.

24. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores instructions, and the instructions are executed by a processor to implement the network topology identification method according to any one of claims 1 to 11.

25. A wireless communication system, characterized in that: The system comprises: a plurality of APs, and a controller according to any one of claims 12 to 23 connected to the plurality of APs.

26. A computer program product, characterized in that The computer program product comprises instructions, and when the computer program product is run on a computer, the computer is enabled to execute the network topology identification method according to any one of claims 1 to 11.

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