KR102415207B1 - Method of Scanning a WiFi Channel in an Access Point - Google Patents

Abstract

A method of scanning a WiFi (Wireless Fidelity) channel in an access point (AP) is provided. The method includes measuring a connection disconnection time period from the time the AP transmits a beacon frame to the disconnection time between the AP and a device connected to the AP via WiFi, the disconnection time period Determining a scan time period based on , controlling the device to reconnect with the AP over WiFi, and scanning a WiFi channel used by the AP during the scan time period.

Description

{Method of Scanning a WiFi Channel in an Access Point}

The disclosed technology relates to an access point (AP), and more particularly, to a technology for scanning a WiFi channel in the AP.

As the use of the Internet has become a part of daily life, the use of APs (Access Points) such as wired and wireless routers has also become common. It is difficult to find places where such APs are not installed in public places such as cafes, company offices, and rest areas, as well as at home. Taking the home as an example, the AP separates the various IT devices that make up the home network and the external Internet network and plays a role of intermediary for interconnection between them.

AP technology is handled as a part of wireless local area network (WLAN) technology, and its standardization is also managed by IEEE, a standardization organization for wireless LAN technology. The early wireless LAN technology supported speeds of 1-2Mbps using the frequency of the 2.4GHz band based on the IEEE 802.11 standard, but recently, with the development of wireless communication technology, based on the WiFi6 standard, It supports speeds up to 600Mbps.

An object of the disclosed technology is to provide a technology for collecting channel information by scanning a channel for as long as possible without affecting the WiFi connection between the AP and client devices in the AP.

The problems to be solved by the disclosed technology are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

In one aspect, a method of scanning a WiFi (Wireless Fidelity) channel in an access point (AP) is provided. The method includes measuring a connection disconnection time period from the time the AP transmits a beacon frame to the disconnection time between the AP and a device connected to the AP via WiFi, the disconnection time period Determining a scan time period based on , controlling the device to reconnect with the AP over WiFi, and scanning a WiFi channel used by the AP during the scan time period.

In one embodiment, measuring the connection release time period from the time when the AP transmits a beacon frame to the time when the connection between the AP and a device connected to the AP by WiFi is released includes: Transmitting the beacon frame, storing a first time at which the AP transmits the beacon frame, and measuring a second time at which the connection between the AP and the device is released while the transmission of the beacon frame is stopped and determining a time obtained by subtracting the first time from the second time as the disconnection time period.

In an embodiment, the second time is a time at which a connection release request signal is received from the device.

In one embodiment, determining a scan time period based on the disconnection time period includes determining a time period less than the disconnection time period as the scan time period.

In an embodiment, the scanning of the WiFi channel used by the AP during the scan time period includes transmitting the beacon frame and not transmitting the beacon frame during the scan time period after transmitting the beacon frame.

In an embodiment, the scanning of the WiFi channel used by the AP during the scan time period includes identifying other APs using the same channel as the WiFi channel used by the AP.

In one embodiment, the method, before the step of measuring a disconnection time period from the time when the AP transmits a beacon frame to the time when the connection between the AP and a device connected to the AP via WiFi is released and transmitting the beacon frame to the device at a predetermined period to control the device to be connected to the AP via WiFi, and after scanning for a WiFi channel used by the AP during the scan time period, the beacon The method further includes transmitting the frame at the predetermined period.

In one embodiment, the method further comprises repeating the scanning of the WiFi channel used by the AP during the scan time period at a predetermined time period.

In an embodiment, the method includes controlling a second device different from the device to be connected to the AP via WiFi, not transmitting the beacon frame during the scan time period after transmitting the beacon frame, and the The method further includes checking whether the connection between the AP and the second device is released before the scan time period expires.

In an embodiment, the method further includes maintaining the scan time period as it is when it is determined that the connection between the AP and the second device is not released before the scan time period expires.

In an embodiment, the method further includes updating the scan time period when it is determined that the connection between the AP and the second device is released before the scan time period expires.

In one embodiment, the step of updating the scan time period includes a time at which the beacon frame is transmitted and a time at which the connection between the AP and the second device is released after the second device is connected to the AP by WiFi. updating the scan time period based on

According to embodiments of the disclosed technology, there is a technical effect of being able to collect channel information by scanning a channel for as long as possible without affecting the WiFi connection between the AP and client devices in the AP.

1 is a diagram illustrating an embodiment of a use environment in which access points (APs) are installed and used.
2A and 2B are diagrams illustrating an embodiment of a flowchart for explaining a method of scanning a WiFi channel in an AP according to the disclosed technology.

Advantages and features of the present invention and a method of achieving them will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in a variety of different forms, and these embodiments merely allow the disclosure of the present invention to be complete and those of ordinary skill in the art to which the present invention pertains. It is provided to fully inform the person of the scope of the invention, and the present invention is only defined by the scope of the claims.

The terms used herein are used only to describe specific embodiments and are not intended to limit the present invention. For example, a component expressed in a singular should be understood as a concept including a plurality of components unless the context clearly means only the singular. In addition, in the specification of the present invention, terms such as 'include' or 'have' are only intended to designate that the features, numbers, steps, operations, components, parts, or combinations thereof described in the specification exist, and such The use of the term does not exclude the possibility of the presence or addition of one or more other features or numbers, steps, operations, components, parts, or combinations thereof. In addition, in the embodiments described in this specification, a 'module' or 'unit' may mean a functional part that performs at least one function or operation.

In addition, unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related art, and unless explicitly defined in the specification of the present invention, it should be interpreted in an ideal or excessively formal meaning. doesn't happen

Hereinafter, embodiments of the present invention will be described in more detail with reference to the accompanying drawings. However, in the following description, when there is a risk of unnecessarily obscuring the gist of the present invention, detailed descriptions of well-known functions and configurations will be omitted.

1 is a diagram illustrating an embodiment of a use environment in which access points (APs) are installed and used.

As shown in FIG. 1 , a plurality of APs 132 , 134 , 136 , and 138 may be distributed in a plurality of rooms of a building. In the illustrated embodiment, a plurality of APs 132, 134, 136, and 138 are disposed on the same floor of a building, but a plurality of APs 132, 134, 136, 138 are distributed on the upper and lower floors. It is possible to arrange such that an environment is created. In the illustrated embodiment, one AP is installed in each of a plurality of rooms, but it is also possible that a plurality of APs are installed in each room. As shown in FIG. 1 , client device 122 , client devices 123 , 124 , 125 , client device 126 and client device 127 are AP 132 , AP 134 , and AP 136 , respectively. ) and the AP 138 through WiFi access to connect to an external Internet network to communicate. In FIG. 1 , the client devices 122-127 respectively connect to the closest APs by WiFi (Wireless Fidelity), but, for example, the client device 125 connects to the AP 136 via WiFi. It is also possible to connect to an AP that is relatively far away instead of an existing AP. The client devices 122-127 may include various types of handheld-based wireless communication devices, such as portable terminals such as laptop PCs, tablet PCs, notebooks, and notepads, and smart phones, etc. The types of the client devices 122-127 are not limited thereto. For example, the client devices 122-127 may include Internet of Things (IoT) consumer electronics devices with communication capabilities, such as a smart multi tap, a smart air conditioner, a smart home lighting device, and the like. .

Each of the plurality of APs 132 , 134 , 136 , and 138 may communicate with the client devices 122-127 using any one of a plurality of standardized channels. A predetermined frequency band is allocated to each of the plurality of channels. If there are, for example, 14 channels available for the AP, channels 1 to 14 are a channel using a frequency of the 2.412 GHz band, a channel using a frequency of the 2.417 GHz band, a channel using a frequency of the 2.422 GHz band, A channel using a frequency of 2.427 GHz band, a channel using a frequency of 2.432 GHz band, a channel using a frequency of 2.437 GHz band, a channel using a frequency of 2.442 GHz band, a channel using a frequency of 2.447 GHz band; A channel using a frequency of 2.452 GHz band, a channel using a frequency of 2.457 GHz band, a channel using a frequency of 2.462 GHz band, a channel using a frequency of 2.467 GHz band, a channel using a frequency of 2.472 GHz band, and It may be a channel using a frequency of the 2.484 GHz band. In general, a plurality of client devices may communicate with the APs through one channel, and the client devices communicating through the same channel may be multiplexed in a time division duplex (TDD) scheme. The plurality of APs 132 , 134 , 136 , and 138 may communicate with the client devices 122-127 using different channels, but may also communicate using the same channel. For example, it is possible for the AP 132 , the AP 134 , and the AP 138 to communicate with the client devices 122-127 using channel 3 on a frequency of the 2.422 GHz band. However, when a large number of APs use the same channel, the channel becomes congested, which increases the channel congestion level (Channel Utilization: CU).

Each of the plurality of APs 132, 134, 136, and 138 can change the channel to an optimal channel with low congestion. It is necessary to measure the congestion level of the channel and further find the optimal channel with low congestion level. In order for the APs 132 , 134 , 136 , and 138 to maintain a connection with the client devices connected to the AP via WiFi, for example, a beacon frame must be transmitted at a predetermined period such as a 100 ms period. The beacon frame may include information for identifying the APs 132 , 134 , 136 , and 138 and information on functions supported by the APs 132 , 134 , 136 , and 138 . The APs 132, 134, 136, and 138 use the same frequency for signal transmission (TX) and reception (RX). The frame cannot be transmitted. In addition, in order to collect channel information with high accuracy from the APs 132, 134, 136, and 138, it is necessary to perform a channel scan for as long as possible. For example, if the channel scan is performed for a long time exceeding 100 ms, a beacon frame The timing at which to transmit is missed, and the WiFi connection with the client devices may be released. For this reason, the channel scan is usually performed at limited time points, such as when the APs 132, 134, 136, and 138 are driven or when the APs 132, 134, 136, and 138 change channels.

In the disclosed technology, while the APs 132, 134, 136, and 138 are connected to WiFi, the channel being used by the APs 132, 134, 136, 138 for as long as possible without affecting the WiFi connection. A technology for collecting information about the corresponding channel by scanning the channel is provided. The APs 132 , 134 , 136 , and 138 may receive WiFi frames being transmitted through the channel being used and check how many frames are being transmitted through the corresponding channel. APs 132, 134, 136, and 138 perform WiFi communication based on BSSID (Basic Service Set Identifier) or MAC (Medium Access Control) (see IEEE 802.11). Since there is information on BSSID/MAC, it is possible to identify the number of APs using the corresponding channel. A method of scanning a WiFi channel according to the disclosed technology is a method of Off-Channel Scanning. Information collected from the APs 132, 134, 136, and 138 may be transmitted to a remote server, where the remote server analyzes the information received from multiple APs by day, month, and/or year, and provides each AP with a specific time zone. You can send a command to change to a specific channel, etc. Accordingly, the APs 132 , 134 , 136 , and 138 can select a WiFi channel suitable for the usage environment to maximize the WiFi capacity in the corresponding environment.

2A and 2B are diagrams illustrating an embodiment of a flowchart for explaining a method of scanning a WiFi channel in an AP according to the disclosed technology.

As shown, the method starts with the step S205 of controlling the client device 122 to be connected to the AP 132 and WiFi by periodically transmitting a beacon frame from the AP 132 ( S205 ). In this step, beacon frames from the AP 132 may be transmitted, for example, at intervals of 100 ms, and signals (Probe Request, Probe Response, Authentication Request, Authentication Response, Association Request, Association Response, EAPOL) may be exchanged. In step S210 , the disconnection time period from the time when the beacon frame is transmitted from the AP 132 to the time when the connection between the AP 132 and the client device 122 is released is measured. In this step, after transmitting the beacon frame from the AP 132 , the time at which the beacon frame is transmitted is stored as the first time, and the connection between the AP 132 and the client device 122 is released while the transmission of the beacon frame is stopped. It is possible to measure the time taken and store it as the second time, and determine the time obtained by subtracting the first time from the second time as the disconnection time period. The reason for performing this step is to check whether the connection between the AP 132 and the client device 122 is released when the beacon frame is not transmitted for a certain amount of time. In an embodiment, the second time, which is a time at which the connection between the AP 132 and the client device 122 is released, is a time at which a dis-Authentication (dis-Association) is received from the client device 122 . . In step S215, the scan time period is determined based on the disconnection time period. In one embodiment, a time period less than the disconnection time period is determined as the scan time period. For example, when the disconnection time period is 240 ms, 200 ms that is less than 240 ms and is a multiple of 100 ms may be determined as the scan time period. As another example, when the disconnection time period is 330 ms, 300 ms that is less than 330 ms and is a multiple of 100 ms may be determined as the scan time period. In one embodiment, a time obtained by subtracting the selected time from the disconnection time period is determined as the scan time period. The scan time period may be the maximum beacon frame transmission interval determined in a line in which the connection between the AP 132 and the client device 122 is not released. In step S220 , the AP 132 periodically transmits a beacon frame to control the client device 122 to reconnect with the AP 132 over WiFi. In step S225, the WiFi channel used by the AP 132 is scanned during the scan time period. In this step, after transmitting the beacon frame, transmission of the beacon frame is stopped during the scan time period and the WiFi channel used by the AP 132 is scanned. During the scan time period, the AP 132 may scan the WiFi channel being used and collect information on the corresponding channel. The AP 132 may receive WiFi frames transmitted through the WiFi channel being used to identify other APs using the corresponding channel. For example, the AP 132 may confirm that the AP 134 and the AP 138 use the same WiFi channel as the WiFi channel used by the AP 132 . When the channel scan is completed, in step S230, the beacon frame may be transmitted again periodically (eg, at intervals of 100 ms).

In step S235 , it is checked whether an additional client device is connected to the AP 132 . If it is determined that an additional client device is not connected to the AP 132 as a result of the check in step S235, the process proceeds to step S240 to check whether a predetermined time period has elapsed. As a result of the inspection in step S240, if it is determined that the selected time period has not elapsed, the process returns to step S240. Meanwhile, if it is determined as a result of the inspection in step S240 that the selected time period has elapsed, the process returns to step S225 and repeats steps S225 and S230. This is to periodically scan the channel. In one embodiment, when the AP 132 scans the channel and it is found that the channel congestion is high, the selected time period in step S235 can be set to be long, and when it is found that the channel congestion is low, in step S235 The selected time period can be set short. For example, when the channel congestion level is high, the selected time period may be set to 1 hour, and if the channel congestion level is low, the selected time period may be set to 10 minutes. Meanwhile, if it is determined that an additional client device is connected to the AP 132 as a result of the check in step S235, the process proceeds to step S245.

In step S245, after transmitting the beacon frame, the beacon frame is not transmitted during the scan time period. In step S250, it is checked whether the connection between the AP 132 and the additional client device is released before the scan time period expires. As a result of the check in step S250 , if it is determined that the connection between the AP 132 and the additional client device is not released before the scan time period expires, the process returns to step S240 . Meanwhile, if it is determined that the connection between the AP 132 and the additional client device is released before the scan time period expires as a result of the inspection in step S250, the scan time period is updated in step S255. In this step, on the basis of the time when the beacon frame is transmitted in step S245 and the time when the connection between the AP 132 and the additional client device is released, in a similar manner as in steps S210 and S215 described above. The scan time period can be determined again. In step S260 , the AP 132 periodically transmits a beacon frame to control the additional client device to be reconnected to the AP 132 and WiFi, and then the process returns to step S240 .

In the above description, the meaning of the description that a component is connected to or coupled to another component not only means that the component is directly connected or coupled to the other component, but also means that one or more other components are interposed therebetween. It should be understood to include the meaning that may be connected or coupled through an element. In addition, terms for describing the relationship between the elements (eg, 'between', 'between', etc.) should also be interpreted with similar meanings.

In the embodiments disclosed herein, the arrangement of the illustrated components may vary depending on the environment or requirements in which the invention is implemented. For example, some components may be omitted or some components may be integrated and implemented as one. Also, the arrangement order and connection of some components may be changed.

In the above, various embodiments of the present invention have been illustrated and described, but the present invention is not limited to the specific embodiments described above, and the above-described embodiments depart from the gist of the present invention as claimed in the appended claims. Without this, various modifications may be made by those of ordinary skill in the art to which the present invention pertains, and these modified embodiments should not be understood separately from the technical spirit or scope of the present invention. Accordingly, the technical scope of the present invention should be defined only by the appended claims.

132; 134, 136, 138: AP
122, 123, 124, 125, 126, 127: client device

Claims (12)

As a method of scanning a WiFi (Wireless Fidelity) channel in an AP (Access Point),
Measuring a disconnection time period from the time when the AP transmits a beacon frame to the time when the connection between the AP and a device connected to the AP via WiFi is disconnected;
determining a scan time period based on the disconnection time period;
controlling the device to reconnect to the AP and WiFi; and
and scanning a WiFi channel used by the AP during the scan time period.
According to claim 1,
Measuring the disconnection time period from the time when the AP transmits a beacon frame to the time when the connection between the AP and a device connected to the AP by WiFi is disconnected includes:
transmitting the beacon frame from the AP;
storing a first time at which the AP transmits the beacon frame;
measuring a second time at which the connection between the AP and the device is released while the transmission of the beacon frame is stopped; and
and determining a time obtained by subtracting the first time from the second time as the disconnection time period.
3. The method of claim 2,
The second time is a time at which the connection release request signal is received from the device, the WiFi channel scanning method.
According to claim 1,
The determining of a scan time period based on the disconnection time period includes determining a time period less than the disconnection time period as the scan time period.
According to claim 1,
The scanning of the WiFi channel used by the AP during the scan time period includes transmitting the beacon frame and not transmitting the beacon frame during the scan time period after transmitting the beacon frame.
According to claim 1,
The scanning of the WiFi channel used by the AP during the scan time period includes identifying other APs using the same channel as the WiFi channel used by the AP.
According to claim 1,
Select the beacon frame as the device before measuring the disconnection time period from the time the AP transmits a beacon frame to the disconnection time between the AP and the device connected to the AP by WiFi The method further comprising the step of controlling the device to connect to the AP by WiFi by transmitting at a specified period, and transmitting the beacon frame at the predetermined period after scanning a WiFi channel used by the AP during the scan time period WiFi channel scanning method further comprising.
According to claim 1,
The method of scanning a WiFi channel further comprising repeating the scanning of the WiFi channel used by the AP during the scan time period at a predetermined time period.
According to claim 1,
controlling a second device different from the device to be connected to the AP via WiFi;
not transmitting the beacon frame during the scan time period after transmitting the beacon frame; and
The method further comprising the step of checking whether the connection between the AP and the second device is released before the scan time period expires.
10. The method of claim 9,
and maintaining the scan time period as it is when it is determined that the connection between the AP and the second device is not released before the scan time period expires.
10. The method of claim 9,
and updating the scan time period when it is determined that the connection between the AP and the second device is released before the scan time period expires.
12. The method of claim 11,
In the updating of the scan time period, the scan time is based on a time at which the beacon frame is transmitted and a time at which the connection between the AP and the second device is released after the second device is connected to the AP by WiFi. A method of scanning WiFi channels, comprising the step of updating a period.

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