KR20180135544A - Method for selecting an operation frequency of an access point and apparatus thereof - Google Patents

Abstract

The present invention relates to a method of selecting an operation frequency band of a dual band AP in a wireless LAN system. The method includes: a step of collecting cell information from one or more APs existing in the wireless LAN system; a step of analyzing the wireless environment of the wireless LAN system using the collected cell information; and a step of determining the operation frequency band of at least one of the APs based on the analyzed wireless environment. It is possible to selectively support a plurality of frequency bands using the same antenna and communication modem.

Description

TECHNICAL FIELD [0001] The present invention relates to a method and apparatus for selecting an operating frequency of a wireless LAN access device,

The present invention relates to a method and apparatus for selecting an operating frequency of a wireless LAN access point. More particularly, the present invention relates to a method and apparatus for adaptively selecting an operating frequency band suitable for a radio environment among the plurality of frequency bands in a wireless LAN system supporting a plurality of frequency bands with the same antenna and a communication modem.

Currently, the frequency band used by the wireless LAN system is divided into the 2.4 GHz band and the 5 GHz band. The 2.4 GHz band wireless LAN is highly exposed to interference from the same system due to interference from other devices (eg, Bluetooth devices, RFID devices, microwave ovens, etc.) using the same radio frequency band and lack of non-overlapping channel resources Cell capacity than the 5GHz band wireless LAN environment. On the other hand, the 5GHz band wireless LAN has a relatively large number of non-overlapping channel resources compared to the 2.4GHz band, so that interference between adjacent channels is small and a wider frequency band can be utilized.

In general, it is advantageous for the WLAN system to use the 5 GHz frequency band in terms of the terminal's speed or cell capacity. However, due to the characteristics of the single band WLAN terminal supporting only the 2.4 GHz band and the frequency band lower than the 5 GHz frequency band, the frequency of the 2.4 GHz band still has a great utility value in terms of cell coverage. Accordingly, a dual band AP (Access Point) having both a frequency characteristic of 2.4 GHz and a frequency characteristic of 5 GHz has been developed.

1, the conventional dual band AP 100 includes a first antenna 110 for transmitting / receiving a radio signal in a 2.4 GHz band (i.e., an RF signal), a first antenna 110 for filtering / A first communication modem 130 for modulating and demodulating a radio signal in the 2.4 GHz band, a second antenna 140 for transmitting / receiving a radio signal in the 5 GHz band, a band pass filter 120 for filtering the frequency in the 5 GHz band, And a second communication modem 160 for modulating and demodulating a radio signal in the 5 GHz band, and the like.

However, despite the development of the dual band AP 100, there is a need to support a higher cell capacity in the same cell area, and the existing 5 GHz frequency band satisfies the requirement There is a problem that it can not be done. Therefore, it is necessary to develop a new type of dual band AP for securing the cell capacity.

The present invention is directed to solving the above-mentioned problems and other problems. Another object of the present invention is to provide a wireless LAN access device capable of selectively supporting a plurality of frequency bands using the same antenna and a communication modem, and a wireless LAN system using the same.

It is another object of the present invention to provide a method and apparatus for detecting a surrounding wireless environment in a wireless LAN system and adaptively selecting an operating frequency of a dual band AP based on the detected wireless environment.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention, unless further departing from the spirit and scope of the invention as defined by the appended claims. It will be possible.

According to an aspect of the present invention, there is provided a method of wireless communication system including collecting cell information from at least one access point (AP) in a wireless LAN system; Analyzing a wireless environment of the wireless LAN system using the collected cell information; And determining an operating frequency band of at least one of the APs based on the analyzed wireless environment.

In this embodiment, the cell information collected from the APs includes information on the number of stations connected to the AP, Received Signal Strength Indicator (RSSI) information, channel-specific noise information, channel utilization information, And information regarding single band stations. Also, the APs in the wireless LAN system may include a dual band AP supporting a plurality of frequency bands with the same antenna and communication modem.

The step of analyzing the radio environment in the operating frequency band selection step may further include checking whether a station whose reception power value RSSI falls below a predetermined threshold among the stations connected to the APs.

The step of analyzing the radio environment may further include checking whether there is an overloaded AP among the APs using the cell information of the APs when there is a station having a received power value below a threshold value.

In addition, the step of analyzing the radio environment may further include checking whether an idle channel of 5 GHz band available in the Overloaded AP exists if the Overloaded AP exists.

The step of analyzing the radio environment may further include checking whether cell roaming of single band stations connected to the overloaded AP is possible when an idle channel of 5 GHz band available in the overloaded AP exists can do.

The step of analyzing the radio environment may further include calculating an expected average yield of stations connected to the overloaded AP when cell roaming of the single band stations is possible and checking whether the calculated estimated average yield exceeds a predetermined reference yield As shown in FIG.

Wherein the operating frequency band determining step selects any one of the first and second operating frequency bands that can be provided to the same antenna in at least one of the APs.

According to another aspect of the present invention, there is provided an AP information collecting unit for collecting cell information from one or more access points (APs) existing in a wireless LAN system; A wireless environment analyzer for analyzing a wireless environment of the wireless LAN system using the collected cell information; And an operating frequency selection unit for determining an operating frequency band of at least one of the APs based on the analyzed radio environment.

In the present embodiment, the operating frequency band selection device may further include an AP control unit for transmitting information on the operating frequency band determined through the operating frequency selection unit to the corresponding AP.

According to another aspect of the present invention, there is provided a wireless access method, comprising: collecting cell information from at least one access point (AP) in a wireless LAN system; Analyzing a wireless environment of the wireless LAN system using the collected cell information; And determining at least one operating frequency band of the APs based on the analyzed wireless environment.

A method of selecting an operating frequency band of a dual band AP according to embodiments of the present invention and an effect of the apparatus will be described below.

According to at least one of the embodiments of the present invention, it is possible to provide a dual-band AP supporting a plurality of operating frequencies with one antenna and a communication modem.

In addition, according to at least one embodiment of the present invention, an optimal operating frequency can be automatically selected from a plurality of operating frequencies supported by a dual-band AP in consideration of a wireless situation in a wireless LAN system.

In addition, according to at least one embodiment of the present invention, the operating frequencies of the dual band APs are automatically changed according to the surrounding wireless environment, so that a higher cell capacity can be supported in the same cell area.

However, the method of selecting an operating frequency band according to the embodiments of the present invention and the effect that the device can achieve are not limited to those described above, and other effects not mentioned are described in the following description And will be apparent to one of ordinary skill in the art.

1 is a block diagram of a conventional dual band AP;
FIG. 2 is a schematic configuration diagram of a wireless LAN system according to an embodiment of the present invention; FIG.
3 is a schematic configuration diagram of a wireless LAN system according to another embodiment of the present invention;
4 is a block diagram of a configuration of a wireless LAN access device according to an embodiment of the present invention;
5 is a configuration block diagram of a master AP or an AP controller according to an embodiment of the present invention;
FIG. 6 is a flowchart illustrating a method of selecting an operating frequency band according to an embodiment of the present invention; FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, wherein like reference numerals are used to designate identical or similar elements, and redundant description thereof will be omitted. The suffix "module" and " part "for the components used in the following description are given or mixed in consideration of ease of specification, and do not have their own meaning or role. That is, the term 'part' used in the present invention means a hardware component such as software, FPGA or ASIC, and 'part' performs certain roles. However, 'minus' is not limited to software or hardware. The " part " may be configured to be in an addressable storage medium and configured to play back one or more processors. Thus, by way of example, and by no means, the terms " component " or " component " means any combination of components, such as software components, object- oriented software components, class components and task components, Subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, databases, data structures, tables, arrays and variables. The functions provided in the components and parts may be combined into a smaller number of components and parts or further separated into additional components and parts.

In the following description of the embodiments of the present invention, a detailed description of related arts will be omitted when it is determined that the gist of the embodiments disclosed herein may be blurred. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. , ≪ / RTI > equivalents, and alternatives.

A method for adaptively selecting an operating frequency band suitable for a wireless environment among the plurality of frequency bands in a wireless LAN system including dual band APs supporting a plurality of frequency bands with the same antenna and a communication modem, Device.

Hereinafter, various embodiments of the present invention will be described in detail with reference to the drawings.

2 is a schematic block diagram of a wireless LAN system according to an embodiment of the present invention.

2, the WLAN system 200 according to an exemplary embodiment of the present invention includes a master AP 210 and at least one Basic Service Set (hereinafter referred to as 'BSS') 220 .

In the WLAN system 200, the master AP 210 may be connected to one or more stations (hereinafter referred to as 'STAs') to form a separate BSS (not shown). At this time, the master AP 210 can perform a general AP operation.

The master AP 210 may perform wired or wireless communication with APs 230 residing in each BSS 220. The master AP 210 monitors the wireless environment in the wireless LAN system 200 based on the information received from each AP 230 and adjusts the operating frequency of the specific AP 230 adaptively based on the wireless environment (Or select) a function to be executed.

In this embodiment, the subject performing the operation frequency band selection algorithm is the master AP 210, and the AP 230, which is the object of the operation frequency selection, is a dual band AP, It is a supporting wireless LAN access device. The plurality of frequency bands supported by the corresponding AP 230 may include an operating frequency of the 2.4 GHz band and an operating frequency of the 5 GHz band, but the present invention is not limited thereto.

The BSS 220 may include an access point (AP) 230 for coordinating a wireless network and one or more stations 240 associated with the AP 230 . The BSS 220 is a collection of APs 230 and stations 240 capable of performing wireless communication while successfully synchronizing with each other, and is not a concept indicating a specific area.

The AP 230 is a functional medium that provides connectivity to the distributed system via the wireless medium for the stations 240 coupled to that BSS 220. In the BSS 220, the communication between the stations 240 is performed via the AP 230, but when a direct link is established, the communication between the stations 240 is performed directly .

AP 230 may be referred to as a centralized controller, a base station (BS), a Node-B, a base transceiver system (BTS), or a site controller in addition to an access point. The station 240 may be a terminal, a wireless transmit / receive unit (WTRU), a user equipment (UE), a mobile station (MS), a mobile terminal, Mobile subscriber unit < / RTI > or the like.

A distributed system (not shown) is a mechanism for one AP 230 to communicate with another AP 230, and is not necessarily a network. If a distributed service defined in IEEE 802.11 can be provided, There is no restriction on this. For example, the distributed system may be a wireless network such as a mesh network, or a physical structure that connects a plurality of APs 230 to each other.

3 is a schematic configuration diagram of a wireless LAN system according to another embodiment of the present invention.

3, the WLAN system 300 according to another embodiment of the present invention may include an AP controller 310 and at least one basic service set (BSS) 320.

In this wireless LAN system 300, the AP controller 310 may be configured as separate hardware and / or software. Unlike the master AP 210 described above, the AP controller 310 does not constitute a separate BSS and does not perform the function of a general AP.

AP controller 310 may perform wired or wireless communication with APs 330 residing in respective BSSs 320. The AP controller 310 monitors the wireless environment in the wireless LAN system 300 based on the information received from each AP 330 and adjusts the operating frequency of the specific AP 330 adaptively based on the wireless environment (Or select) a function to be executed.

In this embodiment, the AP 330 performs the operation frequency band selection algorithm, and the AP 330, which is the object of the operation frequency selection, sets a plurality of frequency bands using the same antenna and communication modem as the dual band AP It is a supporting wireless LAN access device. A plurality of frequency bands supported by the AP 330 may include an operating frequency of the 2.4 GHz band and an operating frequency of the 5 GHz band, but the present invention is not limited thereto.

The BSS 320, the AP 330 and the station 340 shown in FIG. 3 are the same as or similar to the BSS 220, the AP 230 and the station 240 shown in FIG. A detailed description of this is omitted.

4 is a configuration block diagram of a wireless LAN access device according to an embodiment of the present invention.

4, the WLAN access point 400 according to the present invention includes a first communication modem 410, a second communication modem 420, a first filter 430, a second filter 440, A filter 450, a diplexer 460, a first antenna 470, a second antenna 480, and the like. The components shown in FIG. 4 are not essential for implementing a wireless LAN access device, and thus the wireless LAN access device described in this specification can have more or fewer components than those listed above.

The first communication modem 410 performs an operation of modulating and demodulating the radio signal of the first frequency band (for example, the 2.4 GHz band) and the radio signal of the second frequency band (for example, the 5 GHz band) can do.

The second communication modem 420 may perform an operation of modulating and demodulating the radio signal in the second frequency band (e.g., the 5 GHz band).

The first filter 430 may be disposed between the first communication modem 410 and the diplexer 460 to perform an operation of filtering only the radio signals of the first frequency band. The second filter 440 may be disposed between the first communication modem 410 and the diplexer 460 to perform an operation of filtering only the radio signals of the second frequency band. The third filter 450 may be disposed between the second communication modem 420 and the second antenna 480 to perform an operation of filtering only the radio signal of the second frequency band. Here, the first to third filters 430, 440 and 450 may be band pass filters (BPFs), but the present invention is not limited thereto.

A diplexer 460 is disposed between the first antenna 470 and the first and second filters 430 and 440 and outputs two radio signals RF signals To the one antenna 470 and to branch the two radio signals received by the antenna 470 to the two filters 430 and 440.

In other words, the diplexer 460 is a branching filter element used to send and receive two radio signals having different operating frequencies to one antenna. In general, a low pass filter (LPF) And a high pass filter (HPF) through which a high frequency signal passes.

The first antenna 470 may perform an operation of transmitting / receiving a radio signal of the first frequency band and a radio signal of the second frequency band. The second antenna 480 may perform an operation of transmitting / receiving a radio signal of a second frequency band.

As described above, the WLAN access point 400 is a dual band access point (AP) capable of supporting two frequency bands by the same antenna 470 and the communication modem 410. In order to operate the dual band AP, it is necessary to recognize the surrounding radio conditions and automatically select the frequency band to be used among the 2.4GHz and 5GHz frequency bands

5 is a configuration block diagram of a master AP or an AP controller according to an embodiment of the present invention.

5, the master AP or AP controller 500 according to the present invention includes an AP information collecting unit 510, a radio environment analyzing unit 520, an operation frequency selecting unit 530, an AP control unit 540, . The components shown in FIG. 5 are not essential for implementing a master AP or AP controller, so that the master AP or AP controller described herein may have more or fewer components than those listed above have.

The AP information collection unit 510 may collect information of a plurality of APs existing in the wireless LAN systems 200 and 300. To this end, the APs in the systems 200 and 300 can transmit information (hereinafter, referred to as 'cell information') to the master AP or the AP controller 500. The cell information may include information on the number of stations connected to each AP, Received Signal Strength Indicator (RSSI), noise per channel, channel utilization, information on single band stations, have.

The radio environment analysis unit 520 can monitor the surrounding radio environment using the cell information of the APs collected through the AP information collection unit 510. [

First, the radio environment analysis unit 520 determines whether there is a station whose reception power value (RSSI) of the stations connected to each AP falls below a predetermined reference value (threshold value), and determines whether a coverage hole occurs Can be determined.

If the coverage hole is not generated, the radio environment analyzer 520 may determine whether there is an overloaded AP among the APs existing in the WLAN system 200 or 300 based on the cell information of the collected APs. Here, the overloaded AP means an AP that can not provide a minimum yield to the stations connected to the AP.

If the overloaded AP exists, the radio environment analysis unit 520 can determine whether a 5 GHz band available for the corresponding AP exists. At this time, the radio environment analyzer 520 can determine whether there is an idle channel of the 5 GHz band based on the channel state of the 5 GHz band used by the adjacent APs of the overloaded AP.

If there is an idle channel in the 5 GHz band, the radio environment analysis unit 520 determines whether cell roaming of the 2.4 GHz single band stations connected to the overloaded AP is possible based on the cell information of the collected APs .

If it is determined that the 2.4 GHz single-band STAs can access all of the adjacent APs, the radio environment analyzing unit 520 can calculate the expected average yield when operating in the dual 5 GHz mode by switching the operating frequency in the overloaded AP. The radio environment analysis unit 520 may compare the calculated average yield with the predetermined reference yield (mQoS).

The operation frequency selection unit 530 can determine the operation frequency of each AP based on the wireless environment recognized through the wireless environment analysis unit 520. [

The AP control unit 540 can transmit information on the determined operating frequency band to the corresponding AP through the operating frequency selection unit 530. [ The AP may maintain the current operating frequency band or change the operating frequency band to another operating frequency band in accordance with the command of the AP control unit 540. [

As described above, the master AP or AP controller 500 including the above-described components 510 to 540 can adaptively select the operating frequency band of the dual band APs based on the surrounding wireless environment.

6 is a flowchart illustrating an operation frequency band selection method of an AP according to an embodiment of the present invention.

Referring to FIG. 6, the AP controller 500 may collect cell information of a plurality of APs existing in the wireless LAN system 200 (S610). To this end, the APs present in the system 200 receive information on the number of connected stations, RSSI (Received Signal Strength Indicator), channel-specific noise (Noise), channel utilization, Information to the master AP or AP controller 500. Here, the RSSI may include at least one of an uplink RSSI and a downlink RSSI. Likewise, the per-channel noise may include at least one of uplink channel-specific noise and downlink channel-specific noise.

The AP controller 500 can monitor the surrounding wireless environment using the information collected from the APs.

First, the AP controller 500 determines whether there is a station whose reception power value (RSSI) drops below a predetermined reference value (threshold value) in stations connected to each AP, and determines whether a coverage hole occurs (S620).

As a result of checking in step 620, when a coverage hole occurs in the wireless LAN system (i.e., a station having RSSI falling below a predetermined reference value exists), the AP controller 500 sets the operating frequency of the AP to 2.4 GHz band (S680).

For example, when a coverage hole occurs in a specific AP, if the operating frequency of the AP is changed from the 2.4 GHz frequency band to the 5 GHz frequency band, the stations connected to the corresponding AP may have narrow cell coverage due to the frequency characteristics. So you have a lower RSSI. Accordingly, when a coverage hole occurs in the 2.4 GHz / 5 GHz operation mode, the AP controller 500 preferably maintains the operation mode of the AP in the 2.4 GHz / 5 GHz operation mode. Meanwhile, when a coverage hole occurs in the dual 5G mode, the AP controller 500 preferably changes the operation mode of the corresponding AP from the Dual 5G mode to the 2.4G / 5G mode.

As a result of the checking in step 620, if there is no coverage hole in the wireless LAN system (i.e., there is no station having RSSI falling below a predetermined reference value), the AP controller 500 transmits Based on the collected information, it is possible to check whether there is an overloaded AP among the APs existing in the corresponding system 200 (S630).

In this embodiment, an overloaded AP means an AP that can not provide a minimum yield to stations connected to the AP. Accordingly, the AP controller 500 can determine whether an overloaded AP exists by using Equation (1) below. That is, when the average yield of the stations connected to the specific AP does not exceed the predetermined reference yield (mQoS), the AP controller 500 can determine the AP as an overloaded AP.

는 i 번째 AP에서 idle STA들의 예상 데이터 전송률을 계산하는 수학식이고,

은 i 번째 AP에서 Active STA들의 실제 데이터 전송률이다.here,

Is an equation for calculating an expected data transmission rate of idle STAs in the i-th AP,

Is the actual data rate of the active STAs in the i-th AP.

은 i 번째 AP에서 2.4GHz 대역에 접속하는 STA의 수,

은 i 번째 AP에서 5GHz 대역에 접속하는 STA의 수,

은 i 번째 AP에서 2.4GHz 대역의 Active STA 수,

은 i 번째 AP에서 5GHz 대역의 Active STA 수,

은 i 번째 AP에서 2.4GHz 대역의 Channel Utilization,

은 i 번째 AP에서 5GHz 대역의 Channel Utilization,

은 i 번째 AP에 연결된 j 번째 STA의 2.4GHz 대역 Physical rate,

은 i 번째 AP에 연결된 k 번째 STA의 5GHz 대역 Physical rate임.

The number of STAs connecting to the 2.4 GHz band in the i-th AP,

Is the number of STAs connecting to the 5 GHz band in the i-th AP,

The number of active STAs in the 2.4 GHz band in the i-th AP,

The number of active STAs in the 5 GHz band in the i-th AP,

The channel Utilization in the 2.4 GHz band in the i-th AP,

Channel Utilization in the 5GHz band in the i-th AP,

Is the 2.4GHz band physical rate of the jth STA connected to the i-th AP,

Is the physical rate of the 5GHz band of the kth STA connected to the ith AP.

If it is determined in step 630 that no overloaded AP exists, the AP controller 500 can select the operating frequency of the AP to be 2.4 GHz (S680).

If it is determined in step 630 that there is an overloaded AP, the AP controller 500 can determine whether there is an idle channel in the 5 GHz band available in the corresponding AP in step S640. In fact, if there is no channel available in the 5GHz band, then no further processing is required.

The AP controller 500 can determine whether there is an idle channel of the 5 GHz band based on the channel state of the 5 GHz band used by the adjacent APs of the overloaded AP. At this time, the AP controller 500 judges that there is an idle channel if there is a channel other than the 5 GHz band channel used by the adjacent APs, or if the interference magnitude from the corresponding channel is less than the reference value, can do.

If it is determined in operation 640 that there is no idle channel in the 5 GHz band available in the overloaded AP, the AP controller 500 can select the operating frequency of the AP in the 2.4 GHz band in operation S680.

If it is determined in step 640 that there is an idle channel of 5 GHz band available in the overloaded AP, the AP controller 500 determines whether the idle channel exists in the 2.4 GHz single band station It is possible to confirm whether cell roaming is possible (S650). If the overloaded AP operates in Dual 5G mode, single band STAs supporting only 2.4GHz can no longer access the overloaded AP.

AP controller 500 can determine whether cell roaming of single band stations is possible using Equation (2) below. That is, when the single-band STAs existing in the overloaded AP move to the neighbor AP, the AP controller 500 determines that the expected average yield that can be obtained from the neighbor AP exceeds the predetermined reference yield (mQoS) It is possible to determine that cell roaming of the mobile stations is possible. The target AP for each single band STA can be determined as the AP having the highest received power value among the neighbor APs.

은 i 번째 AP에서 2.4GHz 대역에 접속되어 있는 단일 대역 STA들의 수,

은 j 번째 AP에서 2.4GHz 대역에 접속되어 있는 단일 대역 STA들의 수,

는 목적 AP들의 인덱스 집합,

는 목적 AP들의 수,

는 j 번째 AP에서 2.4GHz 대역의 Channel Utilization,

은 j 번째 AP에 연결된 k 번째 STA의 2.4GHz대역 Physical rate임.here,

The number of single-band STAs connected in the 2.4 GHz band in the i-th AP,

Is the number of single-band STAs connected in the 2.4GHz band in the jth AP,

Is the index set of the destination APs,

The number of target APs,

The channel Utilization in the 2.4 GHz band in the jth AP,

Is the 2.4GHz band physical rate of the kth STA connected to the jth AP.

As a result of step 650, if at least one of the single-band STAs existing in the overloaded AP can not access the neighbor AP, the AP controller 500 may select the operating frequency of the corresponding AP as the 2.4 GHz band (S680) .

If it is determined in step 650 that all the single-band STAs existing in the overloaded AP can access the neighbor AP, the AP controller 500 switches the operating frequency in the overloaded AP and estimates The average yield can be calculated. The AP controller 500 may check whether the calculated average yield is above a predetermined reference yield (mQoS) (S660). This is to ensure that when the overloaded AP operates in the Dual 5G mode, it does not perform meaningful frequency switching in a situation where the performance of the STAs is not actually improved.

The AP controller 500 can determine whether to switch the operating frequency of the overloaded AP using Equation (3) below.

은 i 번째 AP에서 2.4GHz 대역에 접속하는 STA의 수,

은 i 번째 AP에서 5GHz 대역에 접속하는 STA의 수,

은 i 번째 AP에서 2.4GHz 대역에 접속되어 있는 단일 대역 STA들의 수,

은 i 번째 AP에 연결된 j 번째 STA의 5GHz 대역 Physical rate임.here,

The number of STAs connecting to the 2.4 GHz band in the i-th AP,

Is the number of STAs connecting to the 5 GHz band in the i-th AP,

The number of single-band STAs connected in the 2.4 GHz band in the i-th AP,

Is the physical rate of the 5GHz band of the jth STA connected to the ith AP.

As a result of checking in step 660, when the expected average yield when operating in the dual 5GHz mode in the overloaded AP does not exceed the predetermined reference yield rate (mQoS), the AP controller 500 sets the operating frequency of the corresponding AP to the 2.4GHz band (S680).

If it is determined in step 660 that the expected average yield of the overloaded AP operating in the dual 5 GHz mode exceeds the predetermined reference yield rate mQoS, the AP controller 500 sets the operating frequency of the corresponding AP to 5 GHz band (S670).

The AP controller 500 may repeatedly perform the operations of steps 610 to 680 until the operation frequency band selection algorithm is terminated (S690).

As described above, the AP controller according to the present invention can monitor the wireless state in the wireless LAN system in real time and automatically change the operation frequency band of the dual band APs based on the wireless state. The AP controller can also select an operating frequency band that can guarantee a predetermined minimum rate of transmission to stations connected to the dual band AP.

It is to be understood by those skilled in the art that the AP controller performs the operation frequency band selection algorithm in the present embodiment, but the present invention is not limited thereto, and the master AP can perform the same algorithm.

The present invention described above can be embodied as computer-readable codes on a medium on which a program is recorded. The computer readable medium includes all kinds of recording devices in which data that can be read by a computer system is stored. Examples of the computer readable medium include a hard disk drive (HDD), a solid state disk (SSD), a silicon disk drive (SDD), a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy disk, , And may also be implemented in the form of a carrier wave (e.g., transmission over the Internet). Accordingly, the above description should not be construed in a limiting sense in all respects and should be considered illustrative. The scope of the present invention should be determined by rational interpretation of the appended claims, and all changes within the scope of equivalents of the present invention are included in the scope of the present invention.

500: master AP or AP controller
510: AP information collecting unit 520: Radio environment analyzing unit
530: Operation frequency selection unit 540: AP control unit

Claims (14)

Collecting cell information from one or more APs (Access Points) existing in a wireless LAN system;
Analyzing a wireless environment of the wireless LAN system using the collected cell information; And
And determining at least one operating frequency band of the APs based on the analyzed wireless environment. The method according to claim 1,
The cell information includes information on the number of stations connected to the AP, Received Signal Strength Indicator (RSSI) information, channel specific noise information, channel utilization information, and information on single band stations Wherein the at least one operating frequency band includes at least one of the frequency bands. The method according to claim 1,
Wherein at least one of the APs is a dual band AP supporting a plurality of frequency bands with the same antenna and a communication modem. 2. The method of claim 1,
Further comprising checking whether a station whose reception power value (RSSI) falls below a predetermined threshold value among stations connected to the APs is checked. 5. The method of claim 4,
Further comprising the step of checking whether there is an overloaded AP among the APs using the collected cell information if there is a station having a received power value below the threshold value. 6. The method of claim 5,
If the average yield of the stations connected to the specific AP does not exceed the predetermined reference yield rate, the AP is determined to be an overloaded AP. 6. The method of claim 5,
Further comprising checking whether an idle channel of 5 GHz band available in the Overloaded AP exists if the Overloaded AP is present. 8. The method of claim 7,
Further comprising checking whether cell roaming of single band stations connected to the overloaded AP is possible if there is an idle channel of 5 GHz band available in the overloaded AP. How to choose. 9. The method of claim 8,
And determining that cell roaming of the single band stations is possible when an expected average yield rate obtainable from a neighbor AP of the overloaded AP exceeds a predetermined reference yield rate. 9. The method of claim 8,
Calculating an expected average yield rate of stations connected to the overloaded AP when cell roaming of the single band stations is possible and checking whether the calculated average yield rate exceeds a predetermined reference yield rate, A method for selecting an operating frequency band. The method of claim 1, wherein the operating frequency band determining step comprises:
Wherein one of the first and second operating frequency bands available for the same antenna is selected from at least one of the APs. An AP information collection unit for collecting cell information from one or more access points (APs) existing in a wireless LAN system;
A wireless environment analyzer for analyzing a wireless environment of the wireless LAN system using the collected cell information; And
And an operation frequency selection unit for determining an operation frequency band of at least one of the APs based on the analyzed radio environment. 13. The method of claim 12,
And an AP controller for transmitting information on an operating frequency band determined through the operating frequency selector to the corresponding AP. A computer readable recording medium storing a program for causing a method according to any one of claims 1 to 11 to be performed on a computer.

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