WO2016085201A1

WO2016085201A1 - Method and system for neighboring access point discovery between multi-band wireless lan access points

Info

Publication number: WO2016085201A1
Application number: PCT/KR2015/012514
Authority: WO
Inventors: 강현덕; 고광진; 김이고르; 송명선
Original assignee: 한국전자통신연구원
Priority date: 2014-11-28
Filing date: 2015-11-20
Publication date: 2016-06-02

Abstract

The present invention relates to method and system for neighboring access point discovery between multi-band wireless LAN access points, the method and system for discovery of a neighboring access point adjacent between access points and for solving an interference problem between access points in a wireless LAN using multiple bands.

Description

Adjacent Access Point Discovery Method Between Multiband Wireless LAN Access Points

The present invention relates to a method and system for wireless communication in a wireless local area network (WLAN), and more particularly, to a method and system for discovering adjacent access points between access points in a WLAN using multiple bands.

With the development of information and communication technology, various wireless communication technologies are being developed. Wireless LANs (WLAN), based on radio frequency technology, personal digital assistants (PDAs), laptop computers, portable multimedia players (PMPs), smart phones (smart phones) ) Is a technology that enables users to access the Internet wirelessly in a home, business, or specific service area using a portable terminal such as a tablet PC or a tablet PC.

The standard for WLAN technology is being developed as an Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard. IEEE 802.11a provides a transmission rate of 54 Mbps using an unlicensed band at 5 GHz. IEEE 802.11b applies a direct sequence spread spectrum (DSSS) at 2.4 GHz to provide a transmission rate of 11 Mbps. IEEE 802.11g applies orthogonal frequency division multiplexing (OFDM) at 2.4 GHz to provide a transmission rate of 54 Mbps. IEEE 802.11n applies multiple input multiple output OFDM (MIMO-OFDM) to provide a transmission rate of 300 Mbps for four spatial streams. IEEE 802.11n supports a channel bandwidth of up to 40 MHz, and in this case, provides a transmission rate of 600 Mbps.

As the spread of the WLAN is activated and the applications using the same are diversified, a need for a new WLAN technology for supporting a higher throughput than the data processing speed supported by IEEE 802.11n has increased. Very high throughput (VHT) WLAN technology is one of the IEEE 802.11 WLAN technologies proposed to support data processing speed of 1Gbps or more. Among them, IEEE 802.11ac is a standard for providing a very high throughput in the sub-6 GHz band, IEEE 802.11ad is a standard for providing a very high throughput in the 60 GHz band.

In addition, standards for various WLAN technologies have been defined and standards are being developed. Typically, IEEE 802.11af is a standard defined for the operation of a WLAN in a TV white space, IEEE 802.11ah is a standard defined to support a large number of terminals operating at low power, IEEE 802.11ai Is a standard defined for fast initial link setup (FILS) in a WLAN system. Recently, the development of the IEEE 802.11ax standard for the purpose of improving the frequency efficiency in a dense environment where a large number of base stations and terminals exist.

Due to the explosion of WLAN networks of various standards, the interference of WLAN devices connected to different adjacent APs, that is, belonging to different BSSs (Basic Service Set), is increasing day by day. In WLAN 802.11ac, the neighboring access point (AP: Access) is used as the 20 MHz / 40 MHz channel width uses the 20 MHz / 40 MHz / 80 MHz / 160 MHz channel width, which is wider than the 802.11n using the 2.4 GHz and 5 GHz bands. The possibility of using partially overlapping or fully overlapping channels between points is increasing, and the interference problem is emerging as an important issue to be solved. Therefore, in order to efficiently use frequency resources, a method for efficient discovery considering bandwidth and channel width between adjacent APs using multiple bands is necessary.

In order to minimize interference between neighboring APs using multiple bands and to efficiently use frequency resources, it is important to know the existence of a multi-banding neighboring AP existing in an area where the AP may interfere with itself. Discovery of a multi-band using neighboring AP may consider the following two cases.

1 is an AP relationship between AP1 and AP2 in which Basic Service Set (BSS) coverage overlaps each other so that use of the same band of the same operation channel may interfere with each other, and two APs may beacon each other in the BSS coverage of AP1 and AP2. (beacon) Indicates a case where a signal can be detected. In this case, AP1 and AP2 do not have a hidden AP relationship with each other, and a separate method for neighboring AP discovery is not required. STA11 and STA12 are terminals connected to AP1, and STA21, STA22, and STA23 are terminals connected to AP2.

Meanwhile, in FIG. 2, AP1 and AP2 have overlapping respective BSS coverages so that when the same operation channel and the partial overlapping operation channel are used in the same band, adjacent AP relationships may interfere with each other. The case exists outside each BSS coverage which cannot detect each other beacon signal. In this case, since AP1 and AP2 cannot grasp each other's existence by magnetic force, they are hidden AP relationships, and a method of discovering each other's existence is needed to avoid interference between BSSs of two APs generated when using the same and partially overlapped operation channels. to be.

Accordingly, the present invention has been made to solve the above-described problem, an object of the present invention, to provide a method and system for discovery of neighboring neighboring APs between APs to solve the interference problem between APs in a WLAN using multiple bands. There is.

Technical problems of the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the following descriptions.

First, to summarize the features of the present invention, the neighbor AP discovery method in a WLAN AP according to an aspect of the present invention for achieving the above object, at least one in each of at least one AP (Access Point) distributed on the WLAN Obtaining first channel scanning information by operating channel search for the first neighboring AP; Collecting second channel scanning information for one or more second neighboring APs obtained by one or more terminals distributed on the WLAN in each of the one or more APs; And comparing the first channel scanning information with the second channel scanning information in each of the one or more APs and transmitting a hidden AP presence notification message including operation channel information for a hidden AP to a specific one of the one or more terminals. And the other one or more APs receiving the hidden AP presence notification message broadcast by the specific terminal to add the operation channel information for the hidden AP to the neighbor AP list.

The specific terminal may be a terminal existing in an overlapping area of cell coverage of a plurality of APs, and the specific terminal is a terminal that detects operation channel information for the largest number of APs among the plurality of terminals providing the second channel scanning information. Can be.

In acquiring the first channel scanning information, for each of the multiple bands, main channel information is detected for each of the first neighboring APs, and subchannel information corresponding to the main channel is determined according to channel arrangement information. In order to detect the interference with the neighboring AP more quickly, channel detection between neighboring APs in the channel in which the subchannel exists may be preferentially performed. Here, the main channel information and the subchannel information is detected from the beacon signal including the channel information for the multiple bands from the neighboring AP, but the n (n is n included in the beacon signal without performing discovery of another band separately). The primary channel information and the subchannel information for the other bands can be detected using the channel information for the other bands.

The first neighbor AP is divided into a single band single channel neighbor AP, a single band multi channel neighbor AP, a multi band single channel neighbor AP, or a multi band multi channel neighbor AP according to whether the channel overlaps or the multi band overlaps. In addition, the operation channel information for each type of the divided neighbor AP may be obtained as the first channel scanning information.

The acquiring of the first channel scanning information may include determining the order of increasing priority as the single band single channel neighbor AP, the single band multi channel neighbor AP, the multi band single channel neighbor AP, and the multi band multi channel neighbor AP. And determining the multi-band multi-channel neighbor AP as a priority interference avoidance target.

In the collecting of the second channel scanning information, for each of the multiple bands, the one or more terminals detect main channel information for each of the second neighboring APs, and correspond to the main channel according to channel arrangement information. By detecting the existing subchannel information, the operation channel information including the detected main channel information and the subchannel information can be obtained as the second channel scanning information.

The neighbor AP discovery method in the WLAN AP may correspond to the AP that has transmitted the Hidden AP existence notification message to the AP that has received the Hidden AP existence notification message, from the AP receiving the Hidden AP existence notification message. Transmitting a confirmation message including connection setting information; And setting, by the AP receiving the confirmation message, connection with the hidden AP through the specific terminal according to the connection setting information with the hidden AP.

In addition, the WLAN AP according to another aspect of the present invention, the channel search unit for searching the operation channel for each of one or more AP (Access Point) distributed on the WLAN; A channel detector obtaining first channel scanning information based on information on an operation channel of at least one first neighboring AP searched by the channel searcher; Collecting second channel scanning information for one or more second neighboring APs acquired by one or more terminals distributed on the WLAN, and detecting the hidden AP by comparing the first channel scanning information with the second channel scanning information. A discovery unit; And a messaging unit configured to transmit a hidden AP presence notification message including operation channel information of the hidden AP to a specific terminal among the one or more terminals according to the detection of the hidden AP, wherein the hidden broadcasted by the specific terminal is performed. The other one or more APs receiving the AP presence notification message may be updated to add the operation channel information for the hidden AP to the neighbor AP list.

The channel search unit detects main channel information for each of the first neighboring APs for each of the multiple bands, and the channel detector exists corresponding to the main channel according to channel configuration information based on the main channel information. While detecting subchannel information, in order to recognize interference with an adjacent AP more quickly, channel detection between adjacent APs in a channel in which a subchannel exists may be preferentially performed. Here, the main channel information and the subchannel information is detected from the beacon signal including the channel information for the multiple bands from the neighboring AP, but the n (n is n included in the beacon signal without performing discovery of another band separately). The primary channel information and the subchannel information for the other bands can be detected using the channel information for the other bands.

The channel detection unit, according to the multi-channel overlapping and multi-band overlapping with respect to the first neighboring AP, single band single channel neighbor AP, single band multi-channel neighbor AP, multi-band single channel neighbor AP, or multi-band multi By dividing the channel into neighboring APs, operation channel information for each type of the divided neighboring APs may be obtained as the first channel scanning information.

The channel detector determines, in order of increasing priority, the single band single channel neighbor AP, the single band multi channel neighbor AP, the multi band single channel neighbor AP, the multi band multi channel neighbor AP, and the multi band multi channel neighbor. The AP may be determined as a priority interference avoidance target.

The at least one terminal detects main channel information for each of the second neighboring APs for each of the multiple bands, and detects subchannel information existing corresponding to the main channel according to channel arrangement information, thereby detecting the detected main channel. Operation channel information including channel information and subchannel information may be obtained as the second channel scanning information.

When the WLAN AP receives a confirmation message including connection setting information with the hidden AP from the specific terminal according to a response from the AP receiving the hidden AP presence notification message to the specific terminal, The apparatus may further include a connection setting unit configured to establish a connection with the hidden AP through the specific terminal according to the connection setting information with the hidden AP.

According to the discovery method and system of neighboring neighboring APs between APs in a WLAN using multiple bands according to the present invention, in case of an AP using multiple bands, channel switching for interference avoidance is performed according to a band and channel interference degree with neighboring APs. Since it is important to set the priority for the AP to be implemented first, the primary channel of the multi-band using AP is detected first, and the channel determined by the WLAN standard based on the channel width information included in the primary channel. By preferentially performing channel detection between adjacent APs in a channel having subchannels according to an allocation criterion, it is possible to recognize interference between adjacent APs due to the use of multi-band multichannels more quickly.

In addition, in the case of an AP using multiple bands, when a beacon signal is directly detected in one band or a channel is detected through channel detection using a cell coverage overlapping area terminal, the discovery of another band is not performed separately. By performing discovery of another band based on the information acquired in the band, there is an advantage of minimizing overhead such as channel detection time required for discovery in multiple bands.

FIG. 1 illustrates a case in which beacon signals of adjacent APs can be detected in a typical WLAN.

FIG. 2 illustrates a case in which a beacon signal between adjacent APs cannot be detected in a typical WLAN.

3 is a view for explaining the concept of a wireless LAN system according to an embodiment of the present invention.

4A is a block diagram for explaining an AP according to an embodiment of the present invention.

4B is a flowchart illustrating an operation for neighboring AP discovery in an AP according to an embodiment of the present invention.

5 shows an example of a WLAN channel width and a channel arrangement method according to an embodiment of the present invention.

6A is a block diagram illustrating a terminal according to an embodiment of the present invention.

6B is a flowchart illustrating an operation for neighbor AP discovery in a terminal according to an embodiment of the present invention.

7A is a block diagram for a further description of an AP according to an embodiment of the present invention.

7B is a flowchart illustrating an operation for neighboring AP discovery using a terminal located in an overlapping area in an AP according to an embodiment of the present invention.

8 shows an example of discovery between adjacent APs using multiple bands of the present invention.

9 illustrates a message exchange method between an AP and an STA for discovery between neighboring APs using multiple bands of the present invention.

10 shows an example of multi-band discovery using one band between adjacent APs using the multi-band of the present invention.

11 is a view for explaining an example of a method of implementing the components of a WLAN system according to an embodiment of the present invention.

As the present invention allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description. However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as the second component, and similarly, the second component may also be referred to as the first component. The term and / or includes a combination of a plurality of related items or any item of a plurality of related items. When a component is referred to as being "connected" or "connected" to another component, it may be directly connected to or connected to that other component, but it may be understood that other components may be present in between. Should be. On the other hand, when a component is said to be "directly connected" or "directly connected" to another component, it should be understood that there is no other component in between.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms such as those defined in the commonly used dictionaries should be construed as having meanings consistent with the meanings in the context of the related art and shall not be construed in ideal or excessively formal meanings unless expressly defined in this application. Do not.

Hereinafter, with reference to the accompanying drawings, it will be described in detail a preferred embodiment of the present invention. In the following description of the present invention, the same reference numerals are used for the same elements in the drawings and redundant descriptions of the same elements will be omitted.

In the present invention, the station (STA) is a physical layer for the medium access control (MAC) and the wireless medium (medium) in compliance with the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard. By any functional medium that includes an interface. The station STA may be divided into a station that is an access point (AP) and a station that is a non-access point (STA). A station (STA), which is an access point (AP), may simply be called an access point (AP), and a station (STA), which is a non-AP, may simply be called a terminal.

The station STA may include a processor and a transceiver, and may further include a user interface and a display device. A processor refers to a unit designed to generate a frame to be transmitted through a wireless network or to process a frame received through a wireless network, and performs various functions for controlling a station (STA). A transceiver is a unit that is functionally connected to a processor and is designed to transmit and receive a frame through a wireless network for a station (STA).

An access point (AP) is a centralized controller, a base station (BS), a radio access station, a node B, an evolved node B, and a mobile multihop relay (MMR) -BS. May refer to a base transceiver system (BTS), a site controller, or the like, and may include some or all of the functions thereof.

The terminal may be a wireless transmit / receive unit (WTRU), a user equipment (UE), a user terminal (UT), an access terminal (AT), a mobile station (MS), May refer to a mobile terminal, a subscriber unit, a subscriber station (SS), a wireless device, or a mobile subscriber unit, and some of them. Or all of the functions may be included.

Here, the terminal may be a desktop computer, a laptop computer, a tablet PC, a wireless phone, a mobile phone, a smart phone, a smart watch capable of communication. (smart watch), smart glass, e-book reader, portable multimedia player (PMP), portable game machine, navigation device, digital camera, digital multimedia broadcasting (DMB) player, digital voice Digital audio recorder, digital audio player, digital picture recorder, digital picture player, digital video recorder, digital video player ) May be included.

3 is a view for explaining the concept of a wireless LAN (eg, IEEE 802.11 WLAN) system 100 according to an embodiment of the present invention.

Referring to FIG. 3, the WLAN system 100 according to an embodiment of the present invention includes at least one basic service set (BSS). The BSS is a set of stations that can successfully synchronize and communicate with each other, and does not mean a specific area.

BSS can be divided into infrastructure BSS (Infrastructure BSS) and independent BSS (Independent BSS, IBSS), in Figure 3 BSS1 (STA1, STA2 (AP1)) and BSS2 (STA3, STA4, STA5 (AP2)) Means BSS. The BSS1 is a distribution system (DS) for connecting a terminal STA1, an access point STA2 (AP1) providing a distribution service, and a plurality of access points STA2 (AP1), STA5 (AP2). ) 110 may be included. In BSS1, the access point STA2 (AP1) may manage the terminal STA1.

The BSS2 may include a distribution system 110 connecting the terminals STA3 and STA4, an access point STA5 (AP2) providing a distribution service, and a plurality of access points STA2 (AP1) and STA5 (AP2). have. In BSS2, the access point STA5 (AP2) may manage the terminals STA3 and STA4.

Meanwhile, an independent BSS (IBSS) is a BSS operating in an ad-hoc mode. Since the IBSS does not include an access point, there is no centralized management entity. That is, in the IBSS, terminals are managed in a distributed manner. In the IBSS, all terminals may be mobile terminals, and thus, are not allowed to be connected to the distribution system (DS), thereby forming a self-contained network.

The access points STA2 (AP1) and STA5 (AP2) may be connected to the distributed system 110 through the wireless medium for the terminals STA 1 / STA 3 and STA 4 connected thereto. Communication between terminals STA 1, STA 3, and STA 4 in BSS 1 or BSS 2 is generally performed through an access point STA 2 (AP 1) or STA 5 (AP 2), but a direct link (direct link) If the link is configured, direct communication between the terminals STA 1, STA 3, and STA 4 is possible.

The plurality of infrastructure BSSs BSS1 and BSS2 may be interconnected through the distribution system 100. The plurality of BSSs BSS1 and BSS2 connected through the distribution system 110 are referred to as an extended service set (ESS). Stations included in the ESS may communicate with each other, and the UE may move from one BSS to another BSS while communicating seamlessly within the same ESS.

The distribution system 110 is a mechanism for one access point AP1 to communicate with another access point AP2, whereby the access points AP1 and AP2 are connected to terminals connected to the BSS they manage. The frame may be transmitted for the UE, or the frame may be transmitted for any UE that has moved to another BSS. Also, the access points AP1 and AP2 may transmit and receive frames with an external network such as a wired network. The distribution system 110 does not necessarily need to be a network, and there is no limitation on its form as long as it can provide a predetermined distribution service defined in the IEEE 802.11 standard. For example, the distribution system 110 may be a wireless network such as a mesh network or a physical structure that connects the access points AP1 and AP2 to each other.

The method and apparatus according to the embodiments of the present invention to be described below may be applied to the IEEE 802.11 WLAN system described above, as well as a wireless personal area network (WPAN) and a wireless body area network (WBAN) as well as an IEEE 802.11 WLAN system. , Mobile Internet such as wireless broadband internet (WiBro) or world interoperability for microwave access (WiMax), 2G mobile communication networks such as global system for mobile communication (GSM) or code division multiple access (CDMA), wideband code division multiple (WCDMA) access or 3G mobile networks such as cdma2000, 3.5G mobile networks such as high speed downlink packet access (HSDPA) or high speed uplink packet access (HSUPA), 4G mobile such as long term evolution (LTE) or LTE-Advanced It can be applied to various networks such as a communication network, a 5G mobile communication network, and the like.

On the other hand, in a WLAN, a frame is largely classified into a data frame, a management frame, and a control frame. The data frame includes data to be transmitted to the terminals STA 1, STA 3, and STA 4, and is transmitted from the upper layer to the terminal. The management frame is used for management supporting IEEE 802.11 services. Control frames are used for control to support the transmission of data frames and management frames.

The management frame includes an association request frame, an association response frame, a reassociation request frame, a reassociation response frame, a probe request frame, and a probe response. ) Frame, beacon frame, authentication frame, action frame and the like.

Control frames include block acknowledgment (ACK) request frames, block ACK frames, power save (POLL) -Poll frames, request to send (RTS) frames, clear to send (CTS) frames, ACK frames, and content free (CF) ) -End frame and the like.

According to the present invention, a neighbor AP discovery method between WLAN APs (AP1, AP2) using multiple bands (eg, 2G, 3G, 3.5G, 4G, 5G, etc.) may be used to select multiple bands at each AP and the UE. In the case of using, by first performing adjacent AP detection in a channel having a subchannel based on channel (width) information included in a primary channel and a channel width extension method according to a WLAN standard, It is possible to effectively perform discovery between adjacent APs using the band. In addition, in the case of an AP using multiple bands, when discovering each other through direct discovery using a beacon signal in one band or channel detection using an overlapping STA, in one band, the discovery of another band is not performed separately. By performing discovery of different bands based on the information obtained in the present invention, a method for minimizing overhead such as channel detection time required for discovery in multiple bands is proposed.

In the present invention, the neighboring APs may be classified into the following four categories to determine the priority of the object to be avoided first when an interference situation occurs.

Single band single channel neighbor AP (e.g. priority 4)

Single-band, multi-channel neighbor AP (eg priority 3)

Multi-band single channel neighboring AP (e.g. Priority 2)

Multi-band multi-channel neighbor AP (e.g. priority 1)

Intuitively, interference avoidance with neighboring APs using multi-band multi-channels has the highest priority, while single-band single channel neighboring APs have the lowest priority.

4A is a block diagram for explaining an AP (AP1 / AP2) according to an embodiment of the present invention. Referring to FIG. 4A, an AP (AP1 / AP2) according to an embodiment of the present invention includes a channel searching unit 210 and a channel detecting unit 220. These operations will be described with reference to the flowchart of FIG. 4B.

4B is a flowchart illustrating an operation for neighboring AP discovery in an AP (AP1 / AP2) according to an embodiment of the present invention.

Referring to FIG. 4B, an AP (AP1 / AP2) according to an embodiment of the present invention may perform neighboring AP discovery in consideration of multiple bands and channel widths as follows. Herein, a method of directly discovering neighboring APs by using beacon signals that can be detected between neighboring APs in one band will be described.

First, the channel search unit 210 searches for a channel in a 2.4 GHz (IEEE 802.11n, etc.) or 5 GHz (IEEE 802.11ac, etc.) band with respect to the neighboring AP based on a beacon signal from one or more neighboring APs (S110). When the operation channel is detected (S120), it is determined whether the detected operation channel is a primary channel (S130).

In addition, the channel detector 220 acquires channel information on the main channel, and based on this, the AP operation channel is assigned to a subchannel corresponding to the main channel according to the channel configuration information (see main channel / subchannel information of FIG. 5). It is checked whether there is any information, and acquires the corresponding operation channel information existing in the subchannel of the neighboring AP, and stores and manages the operation channel information including the obtained main channel and the subchannel information in the storage means (S140). Based on the channel width information included in the main channel, multi-band is detected by first performing channel detection between adjacent APs in a channel having a subchannel over a channel without a subchannel according to a channel allocation standard defined in the WLAN standard. It is possible to recognize the interference between adjacent APs due to the use of multiple channels more quickly and reflect the interference avoidance decision at that time in real time.

The operation channel detection process (S110 ˜ S140) for the neighbor AP is repeated until operation channel information is obtained for all channels in all bands of the neighbor AP (S150).

In addition, when acquisition of operation channel information (main channel and subchannel information) for all bands of the detected neighboring AP is completed, whether multi-channel overlaps with the neighboring AP (S160) and whether multi-band overlaps with the neighboring AP (S161, S162). ), The channel detector 220 may determine a neighbor AP as a single band single channel neighbor AP (S174), a single band multichannel neighbor AP (S171), a multiband single channel neighbor AP (S173), and a multiband multichannel neighbor AP ( As shown in S172, four types of adjacent APs may be classified and stored and managed in the storage means.

When the channel scanning process (S110 ˜ S174) for the neighbor AP is completed as described above, the channel scanning process (S110 ˜ S174) may be repeated for all other detectable neighbor APs to acquire the channel scanning information (S180). .

As described above, the channel detector 220 includes operation channel information (main channel and subchannel information) for each type of the neighboring AP divided according to whether the multi-channel overlaps with the neighboring AP (S160) and the multi-band overlapping with the neighboring AP (S161, S162). ) Can be stored and managed in the storage means as the channel scanning information.

In addition, the channel detection unit 220, for each detected neighbor AP, in order of increasing priority when an interference situation occurs, the single band single channel neighbor AP (S174), single band multichannel neighbor AP (S171), multi band The single channel neighbor AP S173 and the multi band multi channel neighbor AP S172 may be determined, and the multi band multi channel neighbor AP S172 may be determined as the highest interference avoidance target.

In the present invention, the AP / STA is a primary channel having a predetermined channel width of each band (2.4GHz and 5GHz) and one or more subchannels adjacent to the primary channel based on a channel width extension scheme by a WLAN standard. Can be used. Such primary channel and subchannel information may be managed and used in a predetermined lookup-table form.

For example, as shown in FIG. 5, in the 2.4 GHz and 5 GHz bands, as in the case of 802.11n, subchannels such as a single channel (P20) of 20 MHz or multiple channels (channel splicing method, P20, S20) of 40 MHz may be used. . Where P is the primary channel and S is the sub-channel.

In addition, as in the case of 802.11ac, a single channel (P20) of 20 MHz or a multi-channel (channel junction method, P20, S20) of 20 MHz, a multi-channel (channel junction method, S40, P20, S20) of 20 MHz in the 5 GHz band, It is possible to use subchannels such as multiple channels of 160 MHz (channel junction method, S40, P20, S20, S80) and multiple channels of 160 MHz (channel combination method, S40, P20, S20, S40, P20, S20).

6A is a block diagram illustrating a terminal STA1 / STA3 / STA4 according to an embodiment of the present invention. Referring to FIG. 6A, a terminal STA1 / STA3 / STA4 according to an embodiment of the present invention may include a channel search unit 310 and a channel detector 320. These operations will be described with reference to the flowchart of FIG. 6B.

6B is a flowchart illustrating an operation for neighbor AP discovery in a terminal STA1 / STA3 / STA4 according to an embodiment of the present invention.

Referring to FIG. 6B, the terminal STA1 / STA3 / STA4 according to an embodiment of the present invention may perform neighbor AP discovery in consideration of multiple bands and channel widths as follows.

In this case, when beacon signals between adjacent APs cannot be detected, a terminal for neighboring AP discovery using multiple bands by a terminal STA1 / STA3 / STA4 located in an overlapping area of cell coverage (or cell coverage of BSSs) of APs. An operation method of (STA1 / STA3 / STA4) will be described.

First, the channel search unit 310 searches for a channel in a 2.4 GHz (IEEE 802.11n, etc.) or 5 GHz (IEEE 802.11ac, etc.) band with respect to the neighboring AP based on a beacon signal from one or more neighboring APs (S210). When the operation channel is detected (S220), it is determined whether the detected operation channel is a primary channel (S230).

In addition, the channel detector 320 acquires channel information on the main channel, and based on this, the AP operation channel is assigned to a subchannel corresponding to the main channel according to the channel configuration information (see main channel / subchannel information of FIG. 5). In operation S240, the controller 140 determines whether there is a corresponding channel, acquires corresponding operating channel information existing in the subchannel, and stores and manages operating channel information including the primary channel and the subchannel information acquired for the neighboring AP in the storage means (S240).

The operation channel detection process (S210 ˜ S240) for the neighbor AP is repeated until the operation channel information is obtained for all channels in all bands of the neighbor AP (S250).

When the channel scanning process (S210 ˜ S250) for the neighbor AP is completed as described above, the channel scanning process (S210 ˜ S250) may be repeated for all other detectable neighbor APs to acquire the channel scanning information (S260). .

As such, the channel detector 220 may store and manage the operation channel information of each of the neighboring APs in which the operation channel is detected, as the channel scanning information.

7A is a block diagram for further description of an AP (AP1 / AP2) according to an embodiment of the present invention. Referring to FIG. 7A, an AP (AP1 / AP2) according to an embodiment of the present invention includes a channel search unit 210 and a channel detector 220 as shown in FIG. 4A, and in addition, the discovery unit 230. , And may further include a messaging unit 240. These operations will be described with reference to the flowchart of FIG. 7B.

FIG. 7B is a flowchart illustrating an operation for neighboring AP discovery using a terminal located in an overlapping region in an AP (see AP1 / AP2 / A3 of FIG. 8) according to an embodiment of the present invention.

Referring to FIG. 7B, the AP (s) (AP1 / AP2 / A3) according to an embodiment of the present invention may perform neighbor AP discovery in consideration of multiple bands and channel widths as follows.

In this case, when beacon signals between adjacent APs cannot be detected, terminals located in an overlapping area of cell coverage (or cell coverage of BSSs) of APs (eg, STA31 between BSS1-BSS2 of FIG. 8 and BSS2- of FIG. 8). A method of operating an AP for neighboring AP discovery using multiple bands using channel scanning information acquired by the BSS3 (see STA32)) will be described.

First, the AP (s) (AP1 / AP2 / A3) and the terminal (s) (eg, STA11 / STA21 / STA31 / STA32 / STA33 in FIG. 8) distributed in the space each scan a multi-band multi-channel (S310) ). The AP (s) (AP1 / AP2 / A3) performs a channel scanning process (S110 ˜ S180) as shown in FIG. 4B to scan the first channel including operating channel information (main channel and subchannel information) for each type of a neighboring AP. Obtaining information, the terminal (s) (eg, STA11 / STA21 / STA31 / STA32 / STA33 of FIG. 8) performs a channel scanning process (S210 ~ S260) to include the operation channel information for the adjacent AP (s) Second channel scanning information may be obtained.

Next, each terminal (eg, STA11 / STA21 / STA31 / STA32 / STA33 of FIG. 8) performs an association (access) for receiving service from the AP of the corresponding cell coverage (S320).

Next, the discovery unit 230 of each AP (s) (AP1 / AP2 / A3) is a scanning result (second channel) from each associated terminal (eg, STA11 / STA21 / STA31 / STA32 / STA33 of Figure 8) Scanning information) is collected (S330). Here, the discovery unit 230 may transmit a Measurement_Request message to collect channel scanning results obtained by each STA through multi-band multi-channel scanning through a Measurement_Response message (see FIG. 9).

Next, the discovery unit 230 of each AP (s) (AP1 / AP2 / A3) compares its first channel scanning information with the collected second channel scanning information, so that the neighboring AP and the adjacent hidden are hidden. A neighbor AP list is created or updated so that an AP (operating channel information for each type of a neighboring AP) that does not exist in the first channel scanning information is added to the AP (S340).

As described above, in the situation where the terminal (eg, STA11 / STA21 / STA31 / STA32 / STA33 of FIG. 8) associated with the AP (s) (AP1 / AP2 / A3) is spatially distributed, such an update process 340 is performed. Repeated until it is made for each associated terminal (eg, STA11 / STA21 / STA31 / STA32 / STA33 of Figure 8) (S350).

If a hidden AP exists (S360), the discovery unit 230 of the AP may select one or more specific terminals from terminals associated with it (S361). Here, in selecting the specific terminal, the terminal that detected the operation channel information for the AP most frequently by performing scanning among the associated terminals (eg, STA11 / STA21 / STA31 / STA32 / STA33 of FIG. 8), that is, the most APs. It is preferable to select a terminal (eg, STA31) located in an overlapping region of cell coverage. Accordingly, the messaging unit 240 may transmit a hidden AP existence notification message (APDiscovery_Indication) to the specific terminal (S362). The APDiscovery_Indication message may include main channel and subchannel information of the hidden AP.

The predetermined means (eg, the broadcasting unit) of the terminal that receives the APDiscovery_Indication message broadcasts the received message so that the neighboring AP (s) can receive the received message (S363).

The discovery unit 230 of the neighbor AP (s) receiving the broadcast APDiscovery_Indication message compares its first channel scanning information with the collected second channel scanning information, and compares the neighboring AP and the adjacent hidden AP. In operation S370, a neighbor AP list is created or updated so that an AP (operating channel information for each type of a neighboring AP) that does not exist in the first channel scanning information is added.

As such, when the channel scanning information of each AP and the terminal is updated, the other AP (s) and the terminal (s) may share the channel scanning information with each other by repeating the above processes (S310 to S370).

As shown in FIG. 8, for AP1, AP2, and

AP3 using channels

1, 5, 7, and 13 of the 2.4 GHz band and

channels

36, 40, 44, 48, 52, 56, and 60 GHz, each AP and As a result of channel scanning in the terminal STA, channel scanning information may be obtained as shown in Table 1 below according to cell coverage of each AP.

Table 1

In FIG. 8, since AP1 and AP2 and AP1 and AP3 are outside the cell coverage area, they cannot receive beacon signals from each other and thus cannot be detected from each other through channel scanning, resulting in adjacent hidden AP relationships. Since AP2 and AP3 are present in the cell coverage area, they can receive beacon signals from each other and can discover the existence of each other through channel scanning, so that they are adjacent to each other.

Each AP may know the existence of an adjacent hidden AP based on the channel scanning information from the STA associated with it (see S340 of FIG. 7B). In FIG. 8, AP1 and AP2 do not have adjacent hidden APs that can be identified through channel scanning information from STA11 and STA21. In FIG. 8, since STA31 present in the overlapping region of AP1, AP2, and AP3 and STA32 present in the overlapping region of AP2 and AP3 are all associated with AP3, AP3 is a channel from STA31, STA32, and STA33. It is possible to determine that AP1 is the adjacent hidden AP based on the channel scanning information of the STA31 among the scanning information.

Accordingly, AP3 transmits the APDiscovery_Indication message to STA31 to broadcast the channel scanning information to the neighboring AP, and the STA31 receiving the message broadcasts the APDiscovery_Indication message using the active channel used by the neighboring AP. AP1 and AP2, which are the neighboring APs of STA31, receive this message, so that AP1 can discover the presence of AP2 and AP3, and AP2 can discover the presence of AP1.

AP1 and AP2 receiving the APDiscovery_Indication message respond by broadcasting a confirmation message. The confirmation message may include not only a function of acknowledgment but also information necessary for connection setup with these APs and information on an operation channel used by the corresponding AP. Upon receiving these messages, the STA31 transmits a confirmation message to the AP3. AP1 and AP2 may transmit a confirmation message through a beacon signal.

If necessary, such a confirmation message may be omitted. However, when receiving the confirmation message (Confirm Message) as described above, the predetermined means (e.g., connection setting unit) of each AP is required information for connection setup (connection setup) with the hidden AP and the operating channel that the hidden AP is using By receiving the information and the like, connection information with the hidden AP according to the relaying of the STA31 in the overlapping area may be performed using this information.

Based on the exchange of information between such hidden APs (eg, AP1 and AP2 and AP1 and AP3) based on the channel scanning information of the STA31, in FIG. 8, AP1, AP2, and AP3 perform neighbor AP discovery as shown in Table 2 below. You can finish it.

[Table 2]

9 illustrates a message exchange method between an AP and a terminal for discovery between neighboring APs using multiple bands of the present invention.

Referring to FIG. 9, each AP (AP1 / AP2 / AP3) performs multi-band multichannel scanning and transmits a Measurement_Request message to terminals associated with it (STA11 / STA21 / STA31 / STA32 / STA33). In addition, each STA obtains channel scanning information obtained through multi-band multi-channel scanning through a Measurement_Response message. At this time, each STA that receives the Measurement_Request message from the associated AP is configured to preferentially use main channel information used by each AP according to a method of operating an STA for multi-band neighboring AP discovery as described in FIG. 6B. Obtain channel scanning information (S400) for the band multi-channel using AP and transmit the result to the associated AP.

Accordingly, each AP updates a neighbor AP list so that an AP (operating channel information for each type of a neighboring AP) that does not exist in its channel scanning information is added (S500). For example, in FIG. 9, AP3 transmits an APDiscovery_Indication message including operating channel information (channel scanning information) of a hidden AP to STA31, and STA31 uses an APDiscovery_Indication message to be used by neighboring APs (eg, AP1 and AP2). Broadcast using a channel.

The neighboring APs (eg, AP1 and AP2) receiving the broadcast APDiscovery_Indication message compare their channel scanning information with the collected channel scanning information to confirm the existence of the neighboring AP and the hidden hidden AP, A neighbor AP list is created or updated (S600) and a confirmation message is broadcasted so that an AP (operating channel information for each type of a neighboring AP) that does not exist in the channel scanning information is added. Upon receiving these messages, the STA31 transmits a confirmation message to the AP3.

According to the present invention, in the case of an AP (or STA) using multiple bands, if a beacon signal is directly used in one band or if each other is discovered through channel detection using a cell coverage overlapping region STA, discovery of another band is performed. By performing the discovery of the other band based on the information obtained in one band, without performing separately, there is an advantage that can minimize the overhead, such as the channel detection time required for discovery in multiple bands. To this end, an AP using multiple bands may include not only information of a corresponding band (eg, channel information of a 2.4 GHz band) in a beacon signal, but also information of one or more n (n is natural numbers) of other bands (eg, a 5 GHz band). Channel information such as main channel information) may also be transmitted.

FIG. 10 illustrates discovery between AP1 and AP2 in the 2.4 GHz band when AP1 and AP2 using SSID 2.4 GHz and 5 GHz bands transmit information of both bands through beacon signals in the 2.4 GHz and 5 GHz bands. After (Physical Discovery) is performed, the discovery of the 5GHz band (Virtual Discovery) is processed together based on the information obtained in the 2.4GHz band (channel information for two or more bands) to detect the beacon signal in the 5GHz band. Previously, it is possible to complete the discovery of the channel information (main channel and sub channel information) for the two bands.

11 is a view for explaining an example of an implementation method of the elements of the AP, STA, etc. of the WLAN system 100 according to an embodiment of the present invention. Elements of the AP, STA, etc. of the sun system 100 according to an embodiment of the present invention may be made of hardware, software, or a combination thereof. For example, the components such as the AP and the STA of the sun system 100 may be implemented by the computing system 1000 as shown in FIG. 11.

The computing system 1000 may include at least one processor 1100, a memory 1300, a user interface input device 1400, a user interface output device 1500, a storage 1600, and a network connected through a bus 1200. It may include an interface 1700. The processor 1100 may be a central processing unit (CPU) or a semiconductor device that executes processing for instructions stored in the memory 1300 and / or the storage 1600. The memory 1300 and the storage 1600 may include various types of volatile or nonvolatile storage media. For example, the memory 1300 may include a read only memory (ROM) 1310 and a random access memory (RAM) 1320. Thus, the steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied directly in hardware, software module, or a combination of the two executed by the processor 1100. The software module resides in a storage medium (ie, memory 1300 and / or storage 1600), such as RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disks, removable disks, CD-ROMs. You may. An exemplary storage medium is coupled to the processor 1100, which can read information from and write information to the storage medium. In the alternative, the storage medium may be integral to the processor 1100. The processor and the storage medium may reside in an application specific integrated circuit (ASIC). The ASIC may reside in a user terminal. In the alternative, the processor and the storage medium may reside as discrete components in a user terminal.

In addition, embodiments of the present invention may be implemented in the form of program instructions that may be executed by various computer means may be recorded on a computer readable medium. Computer-readable media may include, alone or in combination with the program instructions, data files, data structures, and the like. The program instructions recorded on the computer readable medium may be those specially designed and configured for the embodiments of the present invention, or may be known and available to those skilled in computer software. Computer readable media may refer to hardware devices specifically configured to store and execute program instructions, such as ROM, RAM, flash memory, and the like. Hardware devices may be configured to operate with at least one software module to perform operations in accordance with embodiments of the present invention, and vice versa. The program command may mean a high-level language code that can be executed in a computer based on an interpreter as well as machine code generated by a compiler.

As described above, according to the WLAN system 100 for discovery of neighboring neighboring APs between APs in a WLAN using multiple bands according to the present invention, in case of an AP using multiple bands, band and channel interference with neighboring APs is used. According to the degree, it is important to set the priority for the AP that should first perform channel switching for avoiding interference, so that the primary channel of the multi-band access AP is preferentially detected, and the channel width included in the main channel is preferred. Based on the information, it is preferable to detect the interference between neighboring APs faster by using the multi-band multi-channel by first performing channel detection between neighboring APs in the channel where the sub-channels exist according to the channel allocation criteria determined by the WLAN standard. It is possible. In addition, in the case of an AP using multiple bands, when a beacon signal is directly detected in one band or channels are discovered through channel detection using an overlapping terminal between cell coverages, the discovery of another band is not performed separately. By performing discovery of another band based on information obtained in one band, there is an advantage of minimizing overhead such as channel detection time required for discovery in multiple bands.

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and changes without departing from the essential characteristics of the present invention.

Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

Claims

Acquiring first channel scanning information by operating channel search for one or more first neighboring APs in each of one or more APs distributed on the WLAN;

Collecting second channel scanning information for one or more second neighboring APs obtained by one or more terminals distributed on the WLAN in each of the one or more APs; And

Comparing the first channel scanning information with the second channel scanning information in each of the one or more APs and transmitting a hidden AP presence notification message including operation channel information for a hidden AP to a specific one of the one or more terminals. and,

At least one other AP receiving the hidden AP presence notification message broadcast by the specific terminal is updated to add operation channel information for the hidden AP to a neighbor AP list in a WLAN AP. Way.
The method of claim 1,

The specific terminal is a neighbor AP discovery method in a WLAN AP, characterized in that the terminal exists in the overlapping area of the cell coverage of the plurality of AP.
The method of claim 1,

The specific terminal is a neighbor AP discovery method in a WLAN AP, characterized in that for detecting the operation channel information for the most AP of the plurality of terminals providing the second channel scanning information.
The method of claim 1,

In acquiring the first channel scanning information,

For each of the multiple bands, main channel information is detected for each of the first neighboring APs, and subchannel information corresponding to the main channel is detected according to channel arrangement information, and the interference with the neighboring APs is detected more quickly. The neighbor AP discovery method in the WLAN AP, characterized in that for performing the first channel detection between the neighboring AP in the channel in which the sub-channel exists.
The method of claim 4, wherein

The main channel information and the subchannel information are detected from the beacon signal including the channel information for the multi-band from the neighboring AP, but n included in the beacon signal without performing discovery of another band separately (n is a natural number) The neighbor AP discovery method of the WLAN AP, characterized in that for detecting the main channel information and the sub-channel information for the other band by using the channel information for the other band.
The method of claim 4, wherein

The first neighbor AP is divided into a single band single channel neighbor AP, a single band multi channel neighbor AP, a multi band single channel neighbor AP, or a multi band multi channel neighbor AP according to whether the channel overlaps or the multi band overlaps. The neighbor AP discovery method in the WLAN AP, characterized in that to obtain the operation channel information for each type of the adjacent neighbor AP as the first channel scanning information.
The method of claim 6,

Acquiring the first channel scanning information,

The order of increasing priority is determined as the single band single channel neighbor AP, the single band multi channel neighbor AP, the multi band single channel neighbor AP, the multi band multi channel neighbor AP, and the multiband multi channel neighbor AP is the highest priority avoidance Steps to Decide on Target

Adjacent AP discovery method in a WLAN AP comprising a.
The method of claim 1,

In the collecting of the second channel scanning information,

For each of the multiple bands, the at least one terminal detects main channel information for each of the second neighboring APs, and detects subchannel information existing corresponding to the main channel according to channel arrangement information, thereby detecting the detected main channel. Neighboring AP discovery method in a WLAN AP, characterized in that the operation channel information including channel information and subchannel information is obtained as the second channel scanning information.
The method of claim 1,

In response to the AP receiving the hidden AP presence notification message from the AP, the confirmation message includes connection setting information with the hidden AP to the AP which has transmitted the hidden AP presence notification message. Transmitting c); And

The AP receiving the confirmation message establishes a connection with the hidden AP through the specific terminal according to the connection setting information with the hidden AP.

The neighboring AP discovery method in a WLAN AP, characterized in that it further comprises.
A channel search unit searching for an operation channel with respect to each of at least one access point distributed in the WLAN;

A channel detector obtaining first channel scanning information based on information on an operation channel of at least one first neighboring AP searched by the channel searcher;

Collecting second channel scanning information for one or more second neighboring APs acquired by one or more terminals distributed on the WLAN, and detecting the hidden AP by comparing the first channel scanning information with the second channel scanning information. A discovery unit; And

In response to the detection of the hidden AP, including a messaging unit for transmitting a hidden AP presence notification message including the operation channel information for the hidden AP to a specific terminal of the one or more terminals,

The wireless LAN AP, characterized in that for updating at least one other AP receiving the Hidden AP presence notification message broadcast by the specific terminal to add the operation channel information for the hidden AP to the neighbor AP list.
The method of claim 10,

The specific terminal is a WLAN AP, characterized in that the terminal existing in the overlapping area of the cell coverage of the plurality of AP.
The method of claim 10,

The specific terminal is a WLAN AP, characterized in that for detecting the operation channel information for the largest number of the plurality of terminals providing the second channel scanning information.
The method of claim 10,

The channel search unit detects main channel information for each of the first neighboring APs for each of the multiple bands, and the channel detector exists corresponding to the main channel according to channel configuration information based on the main channel information. The WLAN AP, which detects subchannel information, but preferentially performs channel detection between neighboring APs in a channel in which a subchannel exists in order to recognize interference with an adjacent AP more quickly.
The method of claim 13,

The main channel information and the subchannel information are detected from the beacon signal including the channel information for the multi-band from the neighboring AP, but n included in the beacon signal without performing discovery of another band separately (n is a natural number) WLAN AP, characterized by detecting the main channel information and sub-channel information for the other band using the channel information for the other band.
The method of claim 13,

The channel detection unit, according to the multi-channel overlapping and multi-band overlapping with respect to the first neighboring AP, single band single channel neighbor AP, single band multi-channel neighbor AP, multi-band single channel neighbor AP, or multi-band multi The WLAN AP characterized in that the operation channel information for each type of the divided neighbor AP is obtained as the first channel scanning information.
The method of claim 15,

The channel detector determines, in order of increasing priority, the single band single channel neighbor AP, the single band multi channel neighbor AP, the multi band single channel neighbor AP, the multi band multi channel neighbor AP, and the multi band multi channel neighbor. WLAN AP characterized in that the AP is determined as the highest priority avoidance target.
The method of claim 10,

The at least one terminal detects main channel information for each of the second neighboring APs for each of the multiple bands, and detects subchannel information existing corresponding to the main channel according to channel arrangement information, thereby detecting the detected main channel. And obtaining operating channel information including channel information and subchannel information as the second channel scanning information.
The method of claim 10,

When an AP receiving the hidden AP presence notification message receives a confirmation message including connection setting information with the hidden AP from the specific terminal, the AP establishes a connection with the hidden AP. Connection setting unit for establishing a connection with the hidden AP through the specific terminal according to the information

WLAN AP, characterized in that it further comprises.