WO2011129558A2

WO2011129558A2 - Method and apparatus for identifying channel information in a wireless lan system

Info

Publication number: WO2011129558A2
Application number: PCT/KR2011/002507
Authority: WO
Inventors: 송재형; 곽경철; 최인환; 오항석
Original assignee: 엘지전자 주식회사
Priority date: 2010-04-14
Filing date: 2011-04-08
Publication date: 2011-10-20
Also published as: WO2011129558A3

Abstract

According to one embodiment of the present invention, a method in which a station identifies channel information in a wireless LAN system that includes an AP, which manages a wireless network, and at least one station connected to the AP, comprises the following steps: checking whether or not a primary user is detected in the operating channel of the wireless network; if the primary user is detected, transmitting, to the AP, a first frame containing information on the primary user; receiving, from the AP, a second frame containing information on the channel to which to switch from the operating channel; and analyzing the received second frame to identify information on the channel to which to switch from the operating channel.

Description

Method and apparatus for identifying channel information in WLAN system

The present invention relates to a wireless communication system using a TV white space, and more particularly, to a method and apparatus for identifying channel information in a wireless LAN system.

Currently, the television broadcasting service is moving from analog broadcasting to digital broadcasting. This is because digital broadcasting can provide high quality video and two-way services and use spectrum more efficiently.

This transition to digital broadcasting provides an idle frequency band that can be used by any of the VHF (Very High Frequency, 54 MHz to 88 MHz) band and the UHF (Ultra High Frequency, 174 MHz to 698 MHz) band allocated for the conventional analog broadcasting. An example of such an idle frequency band is a TV white space (hereinafter referred to as TVWS).

That is, TVWS means an empty frequency band not used by broadcasters in the VHF and UHF frequency bands distributed for TV broadcasting, and is an unlicensed frequency band that anyone can use when the conditions for government radio regulations are satisfied. If a licensed device is not in use in this unlicensed frequency band, it is possible for an unlicensed device to use the band. Here, the licensed device refers to a user who is authorized to use the TV white space band and may also be referred to as a primary user or an incumbent user. .

Meanwhile, the Federal Communications Commission (FCC) has approved the frequencies of the VHF and UHF bands used by DTV as unlicensed bands that anyone can use if they meet regulatory requirements set by the FCC.

For example, as shown in FIG. 1, the FCC indicates that there is no licensed device such as a TV signal, a wireless microphone, or the like in the remaining TV channels except for channel 37 (a reserved channel for radio astronomy). In addition, regulations are underway to allow unlicensed devices to use the TV channels. In accordance with the US FCC's policy, other countries are developing corresponding policies and regulations on TV white space.

In addition, various wireless communication systems are being developed for using the TVWS, and the IEEE (Institute of Electrical and Electronics Engineers) 802.11 Working Group uses a wireless local area network (WLAN) system using TVWS as an 802.11af standard. The development is in progress.

The present invention provides a newly defined behavior limits set according to whether or not a TV broadcast exists in an adjacent channel of an operation channel in a wireless network using a TVWS.

The present invention also provides an operating class defined according to a new behavior limits set in a wireless network using TVWS.

The present invention also provides a method and apparatus for identifying an operation class and a channel number of a channel to which stations belonging to the network want to move when performing a channel switch in a wireless network using a TVWS.

The present invention also provides a method and apparatus for an AP belonging to a wireless network to identify information about a primary user presence and adjacent channel behavior limits in a current channel.

The present invention also provides a method and apparatus for an AP belonging to a wireless network to identify information about a primary user presence in another channel and information on adjacent channel behavior limits.

The present invention also provides a method and apparatus for a station belonging to a wireless network to identify information on an operating channel of a neighboring network.

According to an embodiment of the present invention, a wireless LAN system including an AP managing a wireless network and at least one station connected to the AP includes: checking whether a primary user is detected in an operation channel of the wireless network; When the primary user is detected, transmitting a first frame including information about the primary user to the AP; Receiving a second frame including information on a channel to be moved in the operation channel from the AP; And identifying the channel information to be moved by analyzing the received second frame.

According to another embodiment of the present invention, in a wireless LAN system including an AP managing a wireless network and at least one station connected to the AP, a first frame for requesting measurement of a specific channel is provided to the at least one station. Transmitting; Receiving a second frame from the at least one station, the second frame comprising information on whether a primary user exists in the particular channel and whether the primary user causes behavior limitation in an adjacent channel; And analyzing the received second frame to identify information on the specific channel.

Another embodiment of the present invention provides a method for identifying channel information of a station to be moved into an area of a neighboring network in a wireless LAN system including an AP managing a wireless network and at least one station connected to the AP. Transmitting a first frame requesting information about the neighbor network to the AP; Receiving a second frame including information on an operation channel number and an operation class of the neighboring network, from the AP; And analyzing the received second frame to identify information about an operating channel of the neighboring network.

According to an embodiment of the present invention, the wireless LAN devices operating in the TVWS adjusts the maximum transmission power according to whether there is a TV broadcast service in an adjacent channel, thereby eliminating interference with the TV broadcast service existing in the adjacent channel. can do.

On the other hand various other effects will be disclosed directly or implicitly in the detailed description of the embodiments of the present invention to be described later.

1 is a channel map showing a US TV band and a band in which a W-LAN device can operate;

2 illustrates two methods of defining a channel in a WLAN system using TVWS;

3 is a view showing an example of the maximum transmission power limited by the presence and type of primary users present in adjacent channels in the TV white space band;

4 to 7 illustrate a process in which devices belonging to a wireless network perform channel switching using a behavior limits set and an operating class;

FIG. 8 is a diagram illustrating a structure of an extended channel switching announcement frame used by WLAN devices operating in TVWS for channel switching; FIG.

FIG. 9 is a diagram illustrating a structure of an extended channel switching announcement element used by wireless LAN devices operating in TVWS for channel switching; FIG.

10 is a flowchart illustrating a procedure for performing channel switching by devices belonging to a wireless network;

11 and 12 illustrate an example of a process in which a station belonging to a wireless network reports information on a primary user to an AP through wireless measurement;

FIG. 13 is a diagram illustrating a structure of a radio measurement request frame transmitted by an AP operating in TVWS; FIG.

14 illustrates a structure of a radio measurement report frame transmitted by a station operating in TVWS;

15 is a diagram illustrating an example of a radio measurement report frame set when a station belonging to a wireless network detects a primary user causing an adjacent channel behavior restriction;

16 and 17 illustrate another example of a process in which a station belonging to a wireless network reports information on a primary user to an AP through wireless measurement;

18 illustrates an example of a radio measurement report frame set when a station belonging to a wireless network detects a primary user who does not cause an adjacent channel behavior restriction;

19 is a diagram illustrating a flow of a procedure of a station belonging to a wireless network reporting information on a current channel using a radio measurement report frame;

20 and 21 illustrate an example of a process in which devices belonging to a wireless network report a wireless measurement result for a specific channel using a wireless measurement request frame and a wireless measurement report frame;

22 and 23 illustrate another example of a process in which devices belonging to a wireless network report a wireless measurement result for a specific channel using a wireless measurement request frame and a wireless measurement report frame;

FIG. 24 is a flowchart of a procedure for devices belonging to a wireless network to identify information on a specific channel using a radio measurement request frame and a radio measurement report frame; FIG.

25 to 27 illustrate a process in which devices belonging to a wireless network acquire information on an operation channel of a neighbor network using a neighbor report request frame and a neighbor report response frame;

28 illustrates a structure of a neighbor report request frame transmitted by a station operating in TVWS to request information about an adjacent network;

29 illustrates a structure of a neighbor report response frame transmitted by an AP operating in TVWS to report information on a neighbor network;

30 is a diagram illustrating a procedure of a station belonging to a wireless network to identify information about a neighbor network using a neighbor report request frame and a neighbor report response frame;

FIG. 31 is a block diagram illustrating a structure of wireless LAN devices in which embodiments of the present invention can be implemented. FIG.

In the following description of the present invention, detailed descriptions of well-known functions or configurations will be omitted if it is determined that the detailed description of the present invention may unnecessarily obscure the subject matter of the present invention. Terms to be described later are terms defined in consideration of functions in the present invention, and may be changed according to intentions or customs of users or operators. Therefore, the definition should be made based on the contents throughout the specification.

In general, a wireless LAN system performs communication using a channel bandwidth of 5 MHz, 10 MHz, 20 MHz, or 40 MHz in a 2.4 GHz band or a 5 GHz band. However, the channel bandwidth of the TV white space is different by region and / or country, and 6 MHz, 7 MHz, or 8 MHz may be used depending on the region. As described above, since the channel allocation unit in the WLAN system and the channel allocation unit in the TV white space are different from each other, in the WLAN system using TVWS, it is necessary to define a channel according to the channel bandwidth of the TV white space.

For example, FIG. 2 illustrates two methods of defining 5 MHz, 10 MHz, 20 MHz, and 40 MHz channels of a WLAN system in a TV white space band allocated in units of 6 MHz.

Referring to FIG. 2, the first channel definition method (Channelization A) corresponds to the center frequency of the channel for each channel (5/10/20 / 40MHz) of the WLAN system, and the center frequency of the TV channel (6MHz). To be located in. In addition, the second channel definition method (Channelization B) is located at the boundary of two TV channel bands in which the center frequency of the channel is continuous for each channel (5/10/20 / 40MHz) of the WLAN system. To do that. Through these channel definition methods, the wireless LAN system defined in IEEE 802.11 can operate using the frequency band of the TVWS.

Meanwhile, according to the US FCC regulation, in a wireless LAN system operating in a TV white space, when there is no TV signal (or TV broadcast) in a channel adjacent to the current operating channel, the wireless LAN device belonging to the network Defines that they can operate with a transmit power of up to 100 kW. On the other hand, when there is a TV signal in the adjacent channel, it is defined that the wireless LAN devices belonging to the network can operate with a transmission power of up to 40kW. This limits the maximum transmit power of the wireless LAN devices in order to prevent interference with the primary user when a primary user exists in the adjacent channel.

For example, FIG. 3 shows an example of the maximum transmission power limited by the presence or absence of a primary user present in an adjacent channel in the TV white space band.

Referring to FIG. 3, in the case of channel 22, since the primary user does not exist in the

adjacent channels

21 and 23, the wireless LAN devices operating in the channel 22 have a maximum transmit power of 100 kHz. Can send a signal. Meanwhile, in the case of channel 21 and channel 23, since a primary user, that is, a 'TV signal' exists in an adjacent channel, wireless LAN devices operating in channel 21 or channel 23 have a maximum transmit power of 40 kW. Limited to

In the case of channel 40, the primary user exists in

channels

39 and 41, which are adjacent channels. However, when the type of the primary user is a 'wireless microphone (W-MIC) signal' rather than 'TV signal', the wireless LAN devices operating on the channel 40 may transmit a signal with a maximum transmit power of 100 kHz. Can be.

Meanwhile, in FIG. 3, the wireless microphone signal is allocated to channel 39 and channel 41, but is not limited thereto. That is, in accordance with FCC regulations, the wireless microphone signal may be changed to channels other than

channels

39 and 41. In addition, although the wireless LAN devices operating in the TVWS is operating at a transmission power of up to 100 kHz or 40 kHz depending on whether there is a TV signal in the adjacent channel, this also changes to other values in accordance with the FCC regulations can be changed.

As such, the wireless LAN device operating in the TVWS must essentially recognize the maximum power that can be transmitted in the channel in which it operates or the channel to be moved. However, IEEE 802.11af, which defines a wireless LAN system using the TVWS, does not provide a method for allowing the wireless LAN device to identify the maximum power that can be transmitted in a corresponding channel.

Accordingly, in the present invention, a behavior limit set and an operating class newly defined according to whether a TV broadcast (or a TV signal) exists in an adjacent channel of an operation channel in a wireless network using a TVWS. To provide.

Table 1 below shows a behavior limit set in which two newly defined behavior limits are added to an existing behavior limit set of IEEE 802.11. Here, the two behavior limits are classified according to whether there is a TV broadcast in an adjacent channel.

Table 1

Encoding	Behavior limits set	Description
0		Not specified
One	Nomadicbehavior	The location of the station may change but is stationary while in use. The nomadic use EIRP power limits apply if the country allows more than one transmit power limit in the band.This behavior is only specified in bands where behavior 10 License Exempt bands is also allowed.
2	IndoorOnlyBehavior	The location of operation must be 'indoors' as defined in the regulatory domain. Globally, this currently applies only to the 5.15-5.25 GHz band.
3	TransmitPowerControlBehavior	Adaptive transmit power control as defined in the regulatory domain, or clause 11.8 if not defined for the regulatory domain.
...	...	...
15	CCA-EDBehavior	CCA shall also detect a medium busy condition when CCAEnergyDetect detects a channel busy condition.
16	16DFS_50_100_Behavior	A station operating in a band where radiolocation radar is primary, and station operation has in-service monitoring requirements for 50-100㎲ radar pulses.
17	TVWSNonAdjacent ChannelBehavior	A station operating in a TVWS band where broadcast TV operation is primary, and *there is no broadcast TV operation in any of adjacent channels to the TVWS channel on which the station is operating* , and station operation has geolocation database and in-service monitoring requirements. When operating in TVWS, channel numbers are assigned in regulation.
18	TVWSAdjacent ChannelBehavior	A station operating in a TVWS band where broadcast TV operation is primary, and *there is* *a broadcast TV operation in an adjacent channel* *to the TVWS channel on which the station is operating* , and station operation has geolocation database and in-service monitoring requirements. When operating in TVWS, channel numbers are assigned in regulation.
19-255	Reserved

Referring to Table 1, the existing behavior limits set of IEEE 802.11 is defined by assigning 16 behavior limits to encoding values 1 to 16. And, the encoding value 0 defines no behavioral restrictions, and encoding values 19-255 are reserved values for future use.

On the other hand, Table 1 shows the behavior limitations defined in the existing IEEE 802.11, these behavior limitations are not related to the content of the present invention, so a detailed description thereof will be omitted. Therefore, hereinafter, behavior limits newly added to Table 1 will be described.

First, the behavior limits set according to the present invention defines "TVWSNonAdjacentChannelBehavior" assigned to the encoding value 17. The "TVWSNonAdjacentChannelBehavior" refers to behavior restriction when no TV broadcast exists in a channel adjacent to a channel in which a WLAN device using a TVWS is operating.

In addition, the behavior limits set according to the present invention defines "TVWSAdjacentChannelBehavior" assigned to the encoding value 18. The "TVWSAdjacentChannelBehavior" means a behavior restriction when a TV broadcast exists in a channel adjacent to a channel on which a WLAN device using a TVWS operates.

For example, when the behavior limits set is set to "TVWSNonAdjacentChannelBehavior", it means that there is no TV broadcast as a primary user in a channel adjacent to a channel in which devices belonging to a wireless network operate. At this time, the devices belonging to the wireless network can transmit a signal with a transmission power of up to 100 kHz.

When the behavior limits set is set to "TVWSAdjacentChannelBehavior", it means that a TV broadcast as a primary user exists in a channel adjacent to a channel in which devices belonging to a wireless network operate. At this time, the maximum power that can be transmitted by the devices belonging to the wireless network is limited to 40 kW.

Meanwhile, in Table 1, an example of allocating encoding values '17' and '18' to newly defined behavior limits is not limited thereto, and may be changed according to the procedure of IEEE 802.11. .

Table 2 below shows operation classes in which newly defined operation classes are added to existing operating classes of IEEE 802.11. That is, Table 2 below shows behavior classes added by reflecting the behavior limits newly defined in Table 1 above.

And, the operating class (Operating Class) of Table 2 represents the operating class defined in the United States. Therefore, hereinafter, the present invention will be described based on the operating class in the United States.

TABLE 2

Operating Class	Channel Starting Frequency (GHz)	Channel Spacing (MHz)	Channel Set	Behavior Limits Set
One
	5	20	36, 40, 44, 48	NomadicBehavior, IndoorOnlyBehavior
2	5	20	52, 56, 60, 64	NomadicBehavior, DynamicFrequencySelectionBehavior, DFS_50_100_Behavior
...	...	...	...	...
33	2.407	40	5-11	LicenseExemptBehavior, PrimaryChannelUpperBehavior
34	Center on center	40	According to the regulatory	TransmitPowerControlBehavior, DynamicFrequencySelectionBehavior, IBSSRestrictionsBehavior, RegisteredSTABehavior, DependentSTABehavior, PrimaryChannelLowerBehavior, TVWSNonAdjacentChannelBehavior ,
35	Center on center	40	According to the regulatory	TransmitPowerControlBehavior, DynamicFrequencySelectionBehavior, IBSSRestrictionsBehavior, RegisteredSTABehavior, DependentSTABehavior, PrimaryChannelLowerBehavior, TVWSAdjacentChannelBehavior ,
36	Center on center	40	According to the regulatory	TransmitPowerControlBehavior, DynamicFrequencySelectionBehavior, IBSSRestrictionsBehavior, RegisteredSTABehavior, DependentSTABehavior, PrimaryChannelUpperBehavior, TVWSNonAdjacentChannelBehavior ,
37	Center on center	40	According to the regulatory	TransmitPowerControlBehavior, DynamicFrequencySelectionBehavior, IBSSRestrictionsBehavior, RegisteredSTABehavior, DependentSTABehavior, PrimaryChannelUpperBehavior, TVWSAdjacentChannelBehavior ,
38	Center on center	20	According to the regulatory	TransmitPowerControlBehavior, DynamicFrequencySelectionBehavior, IBSSRestrictionsBehavior, RegisteredSTABehavior, DependentSTABehavior, TVWSNonAdjacentChannelBehavior ,
39	Center on center	20	According to the regulatory	TransmitPowerControlBehavior, DynamicFrequencySelectionBehavior, IBSSRestrictionsBehavior, RegisteredSTABehavior, DependentSTABehavior, TVWSAdjacentChannelBehavior ,
40	Center on center	10	According to the regulatory	TransmitPowerControlBehavior, DynamicFrequencySelectionBehavior, IBSSRestrictionsBehavior, RegisteredSTABehavior, DependentSTABehavior, TVWSNonAdjacentChannelBehavior ,
41	Center on center	10	According to the regulatory	TransmitPowerControlBehavior, DynamicFrequencySelectionBehavior, IBSSRestrictionsBehavior, RegisteredSTABehavior, DependentSTABehavior, TVWSAdjacentChannelBehavior ,
42	Center on center	5	According to the regulatory	TransmitPowerControlBehavior, DynamicFrequencySelectionBehavior, IBSSRestrictionsBehavior, RegisteredSTABehavior, DependentSTABehavior, TVWSNonAdjacentChannelBehavior ,
43	Center on center	5	According to the regulatory	TransmitPowerControlBehavior, DynamicFrequencySelectionBehavior, IBSSRestrictionsBehavior, RegisteredSTABehavior, DependentSTABehavior, TVWSAdjacentChannelBehavior ,
44	Center on lower bound	40	According to the regulatory	TransmitPowerControlBehavior, DynamicFrequencySelectionBehavior, IBSSRestrictionsBehavior, RegisteredSTABehavior, DependentSTABehavior, PrimaryChannelLowerBehavior, TVWSNonAdjacentChannelBehavior ,
45	Center on lower bound	40	According to the regulatory	TransmitPowerControlBehavior, DynamicFrequencySelectionBehavior, IBSSRestrictionsBehavior, RegisteredSTABehavior, DependentSTABehavior, PrimaryChannelLowerBehavior, TVWSAdjacentChannelBehavior ,
46	Center on lower bound	40	According to the regulatory	TransmitPowerControlBehavior, DynamicFrequencySelectionBehavior, IBSSRestrictionsBehavior, RegisteredSTABehavior, DependentSTABehavior, PrimaryChannelUpperBehavior, TVWSNonAdjacentChannelBehavior ,
47	Center on lower bound	40	According to the regulatory	TransmitPowerControlBehavior, DynamicFrequencySelectionBehavior, IBSSRestrictionsBehavior, RegisteredSTABehavior, DependentSTABehavior, PrimaryChannelUpperBehavior, TVWSAdjacentChannelBehavior ,
48	Center on lower bound	20	According to the regulatory	TransmitPowerControlBehavior, DynamicFrequencySelectionBehavior, IBSSRestrictionsBehavior, RegisteredSTABehavior, DependentSTABehavior, TVWSNonAdjacentChannelBehavior ,
49	Center on lower bound	20	According to the regulatory	TransmitPowerControlBehavior, DynamicFrequencySelectionBehavior, IBSSRestrictionsBehavior, RegisteredSTABehavior, DependentSTABehavior, TVWSAdjacentChannelBehavior ,
50	Center on lower bound	10	According to the regulatory	TransmitPowerControlBehavior, DynamicFrequencySelectionBehavior, IBSSRestrictionsBehavior, RegisteredSTABehavior, DependentSTABehavior, TVWSNonAdjacentChannelBehavior ,
51	Center on lower bound	10	According to the regulatory	TransmitPowerControlBehavior, DynamicFrequencySelectionBehavior, IBSSRestrictionsBehavior, RegisteredSTABehavior, DependentSTABehavior, TVWSAdjacentChannelBehavior ,
52	Center on lower bound	5	According to the regulatory	TransmitPowerControlBehavior, DynamicFrequencySelectionBehavior, IBSSRestrictionsBehavior, RegisteredSTABehavior, DependentSTABehavior, TVWSNonAdjacentChannelBehavior ,
53	Center on lower bound	5	According to the regulatory	TransmitPowerControlBehavior, DynamicFrequencySelectionBehavior, IBSSRestrictionsBehavior, RegisteredSTABehavior, DependentSTABehavior, TVWSAdjacentChannelBehavior ,
54-255	Reserved	Reserved	Reserved	Reserved

Referring to Table 2, the existing operating class (Operating Class) of IEEE 802.11 defines the operating classes of the index 1 to 15 and the operating classes of the index 22 to 33. In addition, indexes 16 to 21 and indexes 34 to 255 are values that are preliminarily allocated for future use.

In Table 2, the operating classes of the existing IEEE 802.11 (Operating Classes) will be described only for the parts related to the contents of the present invention, and description of the rest of the other parts will be omitted. Therefore, the following description will focus on the newly defined operating classes (Operating Classes) in Table 2.

First, the operating class represents an index for a set of values for radio operation in a WLAN system. In this case, the values for the radio operation include a channel starting frequency, a channel spacing, a channel set, and a behavior limits set.

The channel starting frequency refers to a frequency used together with a channel number to calculate a channel center frequency. The channel start frequency is divided into "Center on center" and "Center on lower bound".

The channel spacing refers to the difference between non-overlapping adjacent channel center frequencies when using the maximum bandwidth allowed in the corresponding operation class. There are 5 MHz, 10 MHz, 20 MHz, and 40 MHz in the channel spacing, and these channel bands may be selectively used according to the frequency band of the empty TVWS.

The channel set represents a set of channel numbers, and the channel numbers may be determined according to a regulation defined for each country. The behavior limits set represents the behavior limits listed in Table 1 above.

In Table 2, the present invention newly defines 20 operating classes from indexes 34 to 53.

First, the operation classes are classified into two types according to the channel starting frequency. That is, when the channel start frequency is "Center on center", it is divided into 10 operating classes, and when the channel start frequency is "Center on lower bound", it is divided into 10 operating classes. As illustrated in FIG. 2, the “center on center” is a channel definition method for positioning the center frequency of the channel at the center frequency of the TV channel for each channel of the WLAN system. In addition, the "Center on lower bound" is a channel definition method for placing the center frequency of the channel at the boundary of two consecutive TV channel bands for each channel of the WLAN system.

The operation classes according to the channel start frequency are further classified into four types according to channel spacing. That is, when the channel interval is "40MHz", it is divided into four operation classes, and when the channel interval is "20MHz", "10MHz," 5MHz ", it is divided into two operation classes.

The motion classes according to the channel interval are divided into two again according to the behavior limits set. That is, the behavior restriction set is classified according to whether "TVWSNonAdjacentChannelBehavior" or "TVWSAdjacentChannelBehavior" is defined in Table 1 above. Here, "TVWSNonAdjacentChannelBehavior" refers to behavior restriction when no TV broadcast exists in a channel adjacent to a channel in which a WLAN device using TVWS operates. In addition, the "TVWSAdjacentChannelBehavior" refers to behavior limitation when there is a TV broadcast in adjacent channels of a channel in which a WLAN device using a TVWS operates.

On the other hand, when the channel interval is "40MHz", two operation classes are additionally defined according to the behavior limits set. That is, the behavior restriction set is distinguished according to whether "PrimaryChannelLowerBehavior" or "PrimaryChannelUpperBehavior". Here, the "PrimaryChannelLowerBehavior" or "PrimaryChannelUpperBehavior" means an action restriction indicating which part of the channel is used for transmission.

For example, IEEE 802.11n defines a High Throughput (HT) operation that provides higher data rates than IEEE 802.11a / g using channel bandwidths of 20 MHz or 40 MHz. In the high throughput (HT) operation, the 40 MHz channel may be used as one channel bandwidth, but may be divided into two channel bandwidths.

That is, the 40 MHz channel may be divided into an upper channel of 20 MHz and a lower channel of 20 MHz. In addition, any one of the upper channel and the lower channel may be set as a primary channel, and the remaining channel may be set as a secondary channel. Here, although the primary channel may be used for transmission of the 20MHz channel of the 40MHz channel, there is a difference that the secondary channel is not used for the transmission 20MHz channel of the 40MHz channel. Accordingly, the "PrimaryChannelLowerBehavior" or "PrimaryChannelUpperBehavior" is an action restriction indicating whether any one of an upper channel and a lower channel is a primary channel.

As such, operation classes according to the present invention may be defined according to the channel start frequency, channel spacing and behavior limit set. By using these operating classes and channel numbers, the wireless LAN devices operating in the TVWS can identify the frequency band and the maximum transmission power and the like in the operating channel.

Meanwhile, in Table 2, the allocation of index '34' to '53' for newly defined operating classes is illustrated, but is not limited thereto and may be changed according to the procedure of IEEE 802.11. .

First embodiment

Hereinafter, a first embodiment of the present invention describes a method for identifying an operation class and a channel number of a channel to which wireless LAN devices belonging to a corresponding network when performing a channel switch in a wireless network.

4 through 7 illustrate a process in which devices belonging to a wireless network perform channel switching using a behavior limits set and an operating class according to the present invention.

4 through 7, the WLAN system includes at least one basic service set (hereinafter, referred to as a BSS) 410 and a distribution system (DS).

The BSS is a set of terminals capable of performing communication while successfully synchronizing, and is not a concept indicating a specific area. In addition, the distributed system is a mechanism for communicating between terminals, and does not necessarily need to be a network. If the distributed system can provide a predetermined distributed service defined in the IEEE 802.11 standard, there is no limitation on the form. For example, the distributed system may be a wireless network such as a mesh network or a physical structure connecting APs to each other.

The BSS 410 is an access point (hereinafter referred to as an AP, 401) for coordinating a corresponding wireless network and

stations

403, 405, and 407 that operate in association with the AP 401. It may be configured to include. Here, it is assumed that the AP 401 and the

stations

403, 405, and 407 present in the BSS 410 are terminals capable of using a TV white space.

The AP 401 is a functional medium that provides access to a distributed system via a wireless medium for the

stations

403, 405, 407 coupled to the wireless network. In addition, the AP 401 manages and controls

stations

403, 405, and 407 belonging to the corresponding wireless network.

The AP 401 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 a name of an access point. In addition, the

stations

403, 405, and 407 may include a terminal, a wireless transmit / receive unit (WTRU), a user terminal (User Equipment, UE), a mobile station (MS), and a portable terminal. May be referred to as a mobile terminal, or another name such as a mobile subscriber unit.

First, referring to FIG. 4, the AP 401 and the

stations

403, 405, and 407 present in the wireless network 410 communicate using channel 22 of the TVWS channel map 420. At this time, since there are no TV signals in

channels

21 and 23, which are channels adjacent to channel 22, the AP 401 and the

stations

403, 405, and 407 belonging to the corresponding network 410 are maximum. Communication is performed at a transmission power of 100 kW.

Subsequently, referring to FIG. 5, while the devices belonging to the wireless network 410 communicate using the channel 22, the TV station starts the TV broadcast 430 using the channel 22.

At this time, the AP 401 may recognize the appearance of the TV broadcast 430 through periodic spectrum sensing. In addition, the AP 401 may know the appearance of the TV broadcast 430 based on the spectrum sensing result reported by the

stations

403, 405, and 407 managed by the AP 401. Here, spectrum sensing refers to an operation in which wireless LAN devices detect whether an authorized device (or a primary user) exists in an area of a corresponding network in a wireless network environment using TVWS.

On the other hand, since the TV broadcast 430 is an authorized user, the network 410 must move to another channel available in the current channel. In the present embodiment, the TV user is described as an example of the authorized user, but the present invention is not limited thereto.

Subsequently, referring to FIG. 6, it is assumed that the corresponding network 410 moves from channel 21 to channel 21 which is a new channel.

At this time, referring to the channel map 420, the TV broadcast does not exist in the adjacent channel of the channel 22 which is the current channel, but the TV broadcast exists in the adjacent channel of the channel 21 which is a new channel. Therefore, wireless LAN devices that want to move to channel 21, which is a new channel, are limited to 40 kW maximum power.

The AP 401 extends the channel switch announcement frame 455 to the

stations

403, 405, and 407 belonging to the network to inform the channel switch and the operating class. Can be transmitted.

In addition, the AP 401 may beacon frame 455 or probe response frame 455 including an extended channel switch announcement element instead of the extended channel switch announcement frame. Can also be transmitted. Here, the extended channel switching notification frame or the extended channel switching notification element includes information about a channel number of a channel to which the WLAN apparatuses want to move and whether TV broadcasting exists in an adjacent channel.

Meanwhile, the beacon frame is a signal periodically transmitted by the AP in order to transmit system information and / or state information of a wireless network to stations belonging to the network. The probe response frame is a signal transmitted by the AP in response to a probe request frame transmitted by a station belonging to a wireless network to request information on the corresponding network.

FIG. 8 illustrates a structure of an extended channel switching announcement frame used by WLAN devices operating in TVWS for channel switching.

Referring to FIG. 8, the extended channel switching notification frame 500 includes a category field 510, an action value field 520, a channel switch mode field 530, a new operating class field 540, and a new channel number field ( 550 and a Channel Switch Count field 560.

The Category field 510 indicates a category of the corresponding frame, and the Action Value field 520 indicates that the corresponding frame is a channel switch frame or an extended channel switch frame.

The Channel Switch Mode field 530 indicates a limitation on transmission in channel switching. For example, the AP 401 may set the Channel Switch Mode field 530 to '0' or '1'. If the Channel Switch Mode field 530 is set to '0', this means that the AP 401 does not impose any requirement on the stations receiving the frame 500. On the other hand, if the Channel Switch Mode field 530 is set to '1', this means that the AP 401 does not transmit a frame to the stations receiving the frame 500 until the channel switching is completed. I mean.

The New Operating Class field 540 indicates an index of the operating class shown in Table 2 above. For example, if the operation class '43' is set in the New Operating Class field 540, the operation class has a channel start frequency of "Center on center", a channel interval of 5 MHz, and a behavior limit set of "TVWSAdjacentChannelBehavior." ". Accordingly, the stations receiving the frame 500 may know the channel definition method and the channel bandwidth in the new channel, and may know that the TV broadcast exists in the adjacent channel of the new channel.

The New Channel Number field 550 indicates a channel number of a channel to which the corresponding network wishes to move. For example, it is assumed in this embodiment that channel 21 is set in the New Channel Number field 550.

The Channel Switch Count field 560 indicates a time at which channel switching is performed after the frame 500 is transmitted. For example, the AP 401 may set the Channel Switch Count field 560 to '0' or '1'. If the Channel Switch Count field 560 is set to '0', this means that the stations receiving the frame 500 perform channel switching after a specific time elapses. On the other hand, if the Channel Switch Count field 560 is set to '1', this means that the stations receiving the frame 500 perform channel switching immediately before the next target beacon transmission time (TBTT).

On the other hand, Figure 9 shows the structure of the extended channel switching announcement element used by the WLAN devices operating in the TVWS for channel switching. The extended channel switch notification element may be transmitted in a beacon frame or a probe response frame.

Referring to FIG. 9, the extended channel switching notification element 600 includes an element ID field 610, a length field 620, a channel switch mode field 630, a new operating class field 640, and a new channel number field ( 650 and a Channel Switch Count field 660.

The Element ID field 610 indicates an identifier (ID) of the corresponding information element, and the Length field 620 indicates the length of the corresponding information element.

The channel switch mode field 630, the new operating class field 640, the new channel number field 650, and the channel switch count field 660 are the channel switch mode field 530 and the new operating class field of FIG. 5. 540 is the same as the New Channel Number field 550 and the Channel Switch Count field 560. Therefore, descriptions of the channel switch mode field 630, the new operating class field 640, the new channel number field 650, and the channel switch count field 660 will be omitted.

Referring back to FIG. 6, the AP 401 sets the "New Operating Class field" and the "New Channel Number field" of the extended channel switch notification frame 500 or the extended channel switch notification element 600. It transmits to the

stations

403, 405, 407 belonging to the network 410. For example, in the present embodiment, the AP 401 sets the New Operating Class field to 43 and transmits the New Channel Number field to 21.

Subsequently, referring to FIG. 7, the

stations

403, 405, and 407 want to move using the extended channel switch notification frame 500 or the extended channel switch notification element 600 received from the AP 401. Analyze the channel number of a channel and the operation class of that channel.

That is, the

stations

403, 405, and 407 may analyze the "New Operating Class field" and the "New Channel Number field" to know the channel definition method and the channel bandwidth in channel 21. In addition, the

stations

403, 405, and 407 may know that a TV broadcast exists in an adjacent channel of the channel 21.

When the above-described channel switch process is completed, the AP 401 and the

stations

403, 405, and 407 belonging to the wireless network communicate with each other using the maximum transmit power of 40 kHz on the new channel 21. You will start again.

10 shows a flow of a procedure in which devices belonging to a wireless network perform channel switching.

Referring to FIG. 10, in step 710, APs and stations existing in a wireless network perform communication using a specific TVWS channel.

In step 720, while the devices belonging to the wireless network are communicating using the current channel, it is checked whether a user, that is, a TV broadcast, is permitted in the channel.

If the TV broadcast does not appear as a result of the check, go to step 710. In step 710, the devices belonging to the network continue to communicate using the current channel. On the other hand, if the TV broadcast appears as a result of the check, go to step 730.

In step 730, the AP must move to a new channel because the current channel is no longer available due to the appearance of a TV broadcast which is an authorized user. Accordingly, the AP transmits to the stations a beacon frame or probe response frame including an extended channel switch announcement frame or an extended channel switch announcement element for channel switching.

That is, the AP sets information on a channel to be newly moved in the "New Operating Class field" and the "New Channel Number field" of the extended channel switching notification frame or the extended channel switching notification element and transmits the information to the stations. .

Then, in step 740, the station receives an extended channel switch announcement frame or a beacon frame or probe response frame including an extended channel switch announcement element from the AP. In operation 750, the station analyzes a new channel number and a new operation class included in the received frame.

When the step 750 is completed, in step 760, the station moves from the current channel to the new channel using the New Channel Number field. Thereafter, in step 770, the station analyzes the New Operating Class field to determine whether there is a TV broadcast in an adjacent channel of the new channel.

As a result of the check, if there is a TV broadcast in the adjacent channel, the control proceeds to step 780. In step 780, the station communicates with a maximum transmit power of 40 kW.

On the other hand, if there is no TV broadcast in the adjacent channel as a result of the check, go to step 790. In step 790, the station communicates at a maximum transmit power of 100 kW.

When the channel switching process is completed through the above-described steps, APs and stations belonging to the wireless network resume communication using a predetermined transmission power in a new channel.

As described above, according to the first embodiment of the present invention, when performing a channel switch in a wireless network, the wireless LAN devices belonging to the corresponding network can identify an operation class and a channel number of a channel to be moved. In addition, through such channel identification, the WLAN apparatuses can remove interference with the TV broadcast present in the adjacent channel by varying the maximum transmission power depending on whether the TV broadcast exists in the adjacent channel.

Second embodiment

Hereinafter, a second embodiment of the present invention describes a method for an AP belonging to a wireless network to identify information about a primary user presence and adjacent channel behavior limits in a corresponding channel.

First, FIG. 11 and FIG. 12 illustrate a process in which a station belonging to a wireless network detects and reports to a AP a primary user causing Adjacent channel behavior limits through radio measurement.

Referring to FIG. 11, a wireless network (BSS) 810 using TVWS includes one AP 801, a first station 803, a second station 805, and a third station connected to the AP 801. (807).

The AP 801 and the first to

third stations

803, 805, and 807 existing in the wireless network communicate using channel 22 of the TVWS channel map 820. At this time, since there is no TV signal in

channels

21 and 23, which are channels adjacent to channel 22, the AP 801 and the first to

third stations

803 and 805 belonging to the corresponding network 810 are not present. 807 performs communication at a maximum transmit power of 100 kHz.

Referring to FIG. 12, it is assumed that a first user 840 using the same channel appears in a corresponding network while the devices belonging to the wireless network 810 communicate using the channel 22.

At this time, the second station 805 in the wireless network 810 detects the appearance of the primary user 840 through periodic spectrum sensing. The second station 805 checks the type of the primary user and whether the primary user has an adjacent channel behavior restriction.

When the confirmation is finished, the second station 805 transmits a radio measurement report frame 830 to the AP 801 to notify the appearance of the primary user. Here, the radio measurement report frame 830 includes information about the presence of a primary user and the presence of an adjacent channel behavior limit.

The radio measurement report frame 830 transmitted by the second station 805 will now be described in detail. In addition, for convenience of description, a radio measurement request frame corresponding to the radio measurement report frame will be described together.

FIG. 13 illustrates a structure of a radio measurement request frame transmitted by an AP operating in TVWS to request channel measurement. Here, the radio measurement request frame transmitted by the AP is configured using a radio measurement request frame defined in IEEE 802.11k.

Referring to FIG. 13, the radio measurement request frame 900 includes a Category field 901, an Action field 903, a Dialog Token field 905, a Number of Repetitions field 907, and a Measurement Request Elements field 909. Include.

The Category field 901 indicates a category of the corresponding frame, and the Action field 903 indicates that the frame is a radio measurement request frame.

The Dialog Token field 905 is a field into which a value selected by a device transmitting a corresponding frame is inserted to identify a frame exchange between an AP and stations.

The Number of Repetitions field 907 indicates the number of repetitions requested for all Measurement Request Elements in the frame.

The Measurement Request Elements field 909 includes an Element ID field 911, a Length field 913, a Measurement Token field 915, a Measurement Request Mode field 917, a Measurement Type field 919, and a Measurement Request field 921. It includes.

The Element ID field 911 indicates an identifier (ID) of the Measurement Request Element, and the Length field 913 indicates a length of the Measurement Request Element.

The Measurement Token field 915 is a field into which a unique value other than zero of measurement request elements in a specific measurement request frame is inserted. The Measurement Request Mode field 917 indicates a bit field including a parallel bit, an enable bit, a request bit, a report bit, and a duration mandatory bit. The measurement type field 919 is a field for inserting a number for identifying a type of a measurement request or a measurement report.

The Measurement Request field 921 includes a Channel Number field 923, a Measurement Start Time field 925, and a Measurement Duration field 927.

The Channel Number field 923 indicates the number of a channel requesting measurement. In addition, the Measurement Start Time field 925 indicates a time for starting channel measurement, and the Measurement Duration field 927 indicates a time for continuing the channel measurement.

14 shows a structure of a radio measurement report frame transmitted by a station operating in TVWS to report channel measurement. Here, the radio measurement report frame transmitted by the station is configured using a radio measurement report frame defined in IEEE 802.11k.

Referring to FIG. 14, the radio measurement report frame 1000 includes a Category field 1001, an Action field 1003, a Dialog Token field 1005, and a Measurement Report Elements field 1009.

The Category field 1001 indicates a category of the corresponding frame, and the Action field 1003 indicates that the corresponding frame is a radio measurement report frame.

The Dialog Token field 1005 is a field into which a value selected by a device transmitting a corresponding frame is inserted to identify a frame exchange between an AP and stations.

The Measurement Report Elements field 1009 includes an Element ID field 1011, a Length field 1013, a Measurement Token field 1015, a Measurement Report Mode field 1017, a Measurement Type field 1019, and a Measurement Report field 1021. It includes.

The Element ID field 1011 indicates an identifier (ID) of the Measurement Report Element, and the Length field 1013 indicates the length of the Measurement Report Element. The Measurement Token field 1015 is a field into which a Measurement Token corresponding to a Measurement Request element is inserted.

The Measurement Report Mode field 1017 is a field indicating why a measurement request failed or was rejected. The Measurement Report Mode field 1017 includes a bit field divided into a late bit, an incapable bit, and a refused bit according to the failed or rejected reason. The Measurement Type field 1019 is a field into which a number for identifying a measurement report is inserted.

The Measurement Report field 1021 includes a Channel Number field 1023, a Measurement Start Time field 1025, a Measurement Duration field 1027, and a Map field 1029.

The Channel Number field 1023 indicates a channel number for reporting a measurement. The Measurement Start Time field 1025 indicates a time at which channel measurement is started, and the Measurement Duration field 1027 indicates a time at which the channel measurement is continued.

The Map field 1029 includes a BSS bit 1031, an OFDM Preamble bit 1033, an Unidentified Signal bit 1035, a Primary User / Radar bit 1037, an Unmeasured bit 1039, and an Adjacent Behavior Limit bit 1041. Include.

The BSS bit 1031 indicates whether to receive at least one valid MAC protocol data unit (MPDU) from another wireless network (BSS) during channel measurement. For example, upon receiving the MPDU, the BSS bit 1031 is set to '1', otherwise the BSS bit 1031 is set to '0'.

The OFDM Preamble bit 1033 indicates whether at least one short training symbol sequence is detected during channel measurement. For example, if the preamble is detected, the OFDM Preamble bit 1033 is set to '1', otherwise the OFDM Preamble bit 1033 is set to '0'.

The Unidentified Signal bit 1035 indicates whether an unidentifiable signal is detected during channel measurement. For example, if the unidentified signal is detected, the Unidentified Signal bit 1035 is set to '1', otherwise the Unidentified Signal bit 1035 is set to '0'.

The Primary User / Radar bit 1037 indicates whether a primary user or radar is detected during channel measurement. In the existing IEEE 802.11k, only the Radar bit is defined, but in the embodiment of the present invention, it is defined by adding a detection of a primary user in addition to the radar. For example, if the primary user is detected, the Primary User / Radar bit 1037 is set to '1', otherwise the Primary User / Radar bit 1037 is set to '0'.

The Unmeasured bit 1039 indicates whether the corresponding channel is measured. For example, if the corresponding channel is not measured, the Unmeasured bit 1039 is set to '1', otherwise the Unmeasured bit 1039 is set to '0'.

The Adjacent behavior limit bit 1041 indicates whether the detected primary user has an Adjacent channel behavior limit on the adjacent channel of the measurement channel. That is, the Adjacent behavior limit bit 1041 indicates whether the primary user is a TV signal. The Adjacent behavior limit bit 1041 is a bit newly defined for the station according to an embodiment of the present invention to inform the AP of the adjacent channel behavior limit.

For example, if the primary user is a TV signal, the Adjacent behavior limit bit 1041 is set to '1', otherwise the Adjacent behavior limit bit 1041 is set to '0'.

Meanwhile, in the present embodiment, the Adjacent behavior limit bit 1041 is inserted into the Map field 1029, but the present invention is not limited thereto and may be inserted into another field.

Referring back to FIG. 12, in the present embodiment, it is assumed that the primary user 840 that appears in the area of the wireless network 810 is a TV broadcast service.

The second station 805 belonging to the wireless network 810 detects a TV signal through periodic spectrum sensing. At this time, the second station 805 reports the information on the TV signal using the radio measurement report frame 1000 proposed in the present invention.

That is, the second station 805 uses the Primary User / Radar bit 1037 and the Adjacent behavior limit bit 1041 in the Map field 1029 of the radio measurement report frame 1000 to the TV signal. Report information.

For example, as shown in FIG. 15, the second station 805 sets the Primary User / Radar bit 1037 and the Adjacent behavior limit bit 1041 of the radio measurement report frame 1000 to '1', respectively. To transmit.

That is, when the Primary User / Radar bit 1037 is set to '1', it means that a primary user has been detected, and when the Adjacent behavior limit bit 1041 is set to '1', the primary user is adjacent to the primary user / Radar bit 1037. It may cause behavioral restriction in the channel. Here, the adjacent channel behavior limit indicates that the maximum transmit power in the adjacent channel is limited to 40 kHz by the TV signal.

The AP 801 receives the radio measurement report frames 830 and 1000 from the second station 805. In addition, the AP 801 uses the Primary User / Radar bit 1037 and the Adjacent behavior limit bit 1041 that exist in the Map field 1029 of the radio measurement report frame 1000, and whether or not the primary user is present. Information on the presence or absence of the restriction of the adjacent channel behavior can be obtained.

In addition, the AP 801 attempts a channel switch process using this information. In this case, the AP 801 and the

stations

803, 805, and 807 perform the channel switching process according to the first embodiment of the present invention described above.

Meanwhile, FIGS. 16 and 17 illustrate a process in which a station belonging to a wireless network detects and reports to a AP a primary user who does not cause Adjacent channel behavior limits through radio measurement.

Referring to FIG. 16, an AP 801 and first to

third stations

803, 805, and 807 existing in a wireless network 810 using TVWS use channel 22 of the TVWS channel map 820. To communicate.

Referring to FIG. 17, while devices belonging to the wireless network 810 communicate using channel 22, a primary user 845 using the same channel appears in the network. In this case, it is assumed that the primary user 845 is a wireless microphone (W-MIC).

The second station 805 belonging to the wireless network 810 detects the wireless microphone signal through periodic spectrum sensing. At this time, the second station 805 reports the information on the wireless microphone signal using the radio measurement report frames 835 and 1000 proposed in the present invention.

That is, the second station 805 uses the Primary User / Radar bit 1037 and the Adjacent Behavior limit bit 1041 present in the Map field 1029 of the radio measurement report frame 1000. Report information about.

For example, as shown in FIG. 18, the second station 805 may set the Primary User / Radar bit 1037 of the radio measurement report frame 1000 to '1' and the Adjacent behavior limit bit 1041. Set as '0' and send.

That is, when the Primary User / Radar bit 1037 is set to '1', it means that a primary user has been detected, and when the Adjacent behavior limit bit 1041 is set to '0', the primary user is adjacent to the primary user / Radar bit 1037. It does not cause channel behavior limitation.

The AP 801 receives the radio measurement report frames 835 and 1000 from the second station 805. In addition, the AP 801 uses the Primary User / Radar bit 1037 and the Adjacent behavior limit bit 1041 that exist in the Map field 1029 of the radio measurement report frame 1000, and whether or not the primary user is present. Information on the presence or absence of the restriction of the adjacent channel behavior can be obtained.

stations

19 shows a flow of a procedure of a station belonging to a wireless network to report information on a current channel using a radio measurement report frame.

Referring to FIG. 19, in step 1410, APs and stations existing in a wireless network perform communication using a specific TVWS channel.

In step 1420, while performing communication using the specific channel, a primary user using the same channel appears in the network. At this time, a station belonging to the wireless network detects the signal of the primary user through periodic spectrum sensing.

In step 1430, the station checks whether the detected primary user induces behavior restriction on the adjacent channel. That is, the station checks whether the primary user is a TV signal.

As a result of the check, if the primary user causes the behavior restriction in the adjacent channel, the flow proceeds to step 1440. In step 1440, the station sets the Primary User / Radar bit 1037 of the Map field 1029 present in the radio measurement report frame 1000 to '1' and sets the Adjacent behavior limit bit 1041. Set to '1' and send.

On the other hand, if the primary user does not cause behavior limitation in the adjacent channel, the first user moves to step 1450. In step 1450, the station sets the Primary User / Radar bit 1037 of the Map field 1029 present in the radio measurement report frame 1000 to '1' and sets the Adjacent behavior limit bit 1041. Set as '0' and send.

Then, in step 1460, the AP receives a radio measurement report frame 1000 from the station. The AP initiates a channel switching process using channel information included in the radio measurement report frame.

Through the above-described steps, the AP can identify the presence of a primary user in the corresponding channel and behavior limits for the adjacent channel using the radio measurement report frame received from the station.

Third embodiment

Hereinafter, a third embodiment of the present invention describes a method for an AP belonging to a wireless network to identify information about a primary user presence and neighbor channel behavior limits in another channel.

First, FIGS. 20 and 21 illustrate an example of a process in which devices belonging to a wireless network report a wireless measurement result for a specific channel using a wireless measurement request frame and a wireless measurement report frame.

Referring to FIG. 20, the AP 1501 and the first to

third stations

1503, 1505, and 1507 existing in the wireless network 1510 using the TVWS use channel 22 of the TVWS channel map 1520. To communicate.

Referring to FIG. 21, the AP 1501 transmits a radio measurement request frame 1530 to the second station 1505 to request radio measurement for a specific channel. In this case, the AP 1501 may use the radio measurement request frame of FIG. 13 described above.

That is, the AP 1501 sets and transmits a channel number field 923, a measurement start time field 925, and a measurement duration field 927 of the radio measurement request frame 900.

Meanwhile, in the present embodiment, it is assumed that the channel for which the AP 1501 requests radio measurement is channel 43, and a TV broadcast service is used for the corresponding channel.

When the wireless measurement request frame 1530 is received from the AP 1501, the second station 1505 analyzes the wireless measurement request frame 1530 to obtain a channel number requested by the AP 1501. Serve

The second station 1505 measures the corresponding channel to determine whether there is a primary user and whether there is a restriction on the behavior of the adjacent channel. The second station 1505 generates and transmits a radio measurement report frame 1540 including information on the presence or absence of the primary user and the adjacent channel behavior limit to the AP 1501. .

In this case, the second station 1505 may use the radio measurement report frame 1000 of FIG. 14 proposed by the present invention. Accordingly, the second station 1505 sets and transmits a Primary User / Radar bit 1037 and an Adjacent Behavior limit bit 1041 present in the Map field 1029 of the radio measurement report frame 1000.

In this embodiment, since the TV broadcast service exists in the specific channel, the second station 1505 sets the Primary User / Radar bit 1037 of the radio measurement report frame 1000 to '1'. And the Adjacent behavior limit bit 1041 to '1'.

Thereafter, the AP 1501 receives the radio measurement report frame 1540 from the second station 1505. In addition, the AP 1501 may acquire information on the presence or absence of the primary user and the restriction of the adjacent channel behavior by using the received radio measurement report frame 1540.

In addition, the AP 1501 attempts a channel switch process using this information. At this time, the AP 1501 and the

stations

1503, 1505, and 1507 perform the channel switching process according to the first embodiment of the present invention described above.

22 and 23 illustrate another example of a process in which devices belonging to a wireless network report a wireless measurement result for a specific channel using a wireless measurement request frame and a wireless measurement report frame.

Referring to FIG. 22, the AP 1501 and the first to

third stations

Referring to FIG. 23, the AP 1501 transmits a radio measurement request frame 1535 to the second station 1505 to request radio measurement for a specific channel.

Meanwhile, in the present embodiment, it is assumed that the channel for which the AP 1501 requests measurement is channel 39, and a wireless microphone (W-MIC) is used for the corresponding channel.

Upon receiving the radio measurement request frame 1535 from the AP 1501, the second station 1505 analyzes the radio measurement request frame 1535 to obtain a channel number requested by the AP 1501. Serve

The second station 1505 measures the corresponding channel to determine whether there is a primary user and whether there is a restriction on the behavior of the adjacent channel. The second station 1505 generates and transmits a radio measurement report frame 1545 including information about the presence of the primary user and the adjacent channel behavior limit to the AP 1501. .

In this embodiment, since the wireless microphone signal exists in the specific channel, the second station 1505 sets the Primary User / Radar bit 1037 of the radio measurement report frame 1545 to '1'. And the Adjacent behavior limit bit 1041 to '0'.

Thereafter, the AP 1501 receives the radio measurement report frame 1545 from the second station 1505. In addition, the AP 1501 may acquire information about the presence or absence of the primary user and the restriction of the adjacent channel behavior by using the received radio measurement report frame 1545.

stations

FIG. 24 illustrates a procedure in which devices belonging to a wireless network identify information on another channel using a wireless measurement request frame and a wireless measurement report frame.

Referring to FIG. 24, in step 1710, APs and stations existing in a wireless network perform communication using a specific channel.

In step 1720, the AP transmits a radio measurement request frame to a specific station to request radio measurement for another channel.

In step 1730, the specific station analyzes the received radio measurement request frame to determine the channel number requested by the AP. The specific station then performs a measurement on the channel corresponding to the channel number.

In step 1740, the specific station determines whether the primary user is detected in the measured channel. As a result of the check, if the primary user is not detected, the process moves to step 1750, and if the primary user is detected, the process moves to step 1760.

In step 1750, if the primary user is not detected, the specific station transmits a radio measurement report frame in which the Primary User / Radar bit is set to '0' to the AP. Next, in step 1790, the AP initiates a channel switching process using channel information included in the radio measurement report frame.

Meanwhile, in step 1760, when the primary user is detected, the specific station checks whether the detected primary user induces behavior restriction on an adjacent channel. That is, the specific station checks whether the primary user is a TV signal.

As a result of the check, if the primary user causes behavior limitation in the adjacent channel, the process moves to step 1770. In step 1770, the specific station sets the Primary User / Radar bit of the Map field present in the radio measurement report frame to '1' and sets the Adjacent behavior limit bit 1041 to '1'. .

On the other hand, if the check result, the primary user does not cause behavior limitation in the adjacent channel, go to step 1780. In step 1780, the specific station sets the Primary User / Radar bit of the Map field present in the radio measurement report frame to '1' and sets the Adjacent behavior limit bit to '0' for transmission.

Then, in step 1790, the AP receives a radio measurement report frame from the specific station. The AP initiates a channel switching process using channel information included in the radio measurement report frame.

Through the above-described steps, the AP may identify the presence of a primary user in another channel and behavior limits for an adjacent channel by using the received radio measurement report frame.

Fourth embodiment

Hereinafter, a fourth embodiment of the present invention describes a method for identifying information on a TVWS channel that a station belonging to a wireless network uses in a neighbor network.

First, FIG. 25 to FIG. 27 illustrate a process in which devices belonging to a wireless network acquire information on an operation channel of a neighbor network using a neighbor report request frame and a neighbor report response frame. Hereinafter, for convenience of explanation, it is assumed that the wireless network is "wireless network A", and the neighboring network is assumed to be "wireless network B".

25 and 26, the wireless network A 1820 may identify an AP 1821 managing a corresponding wireless network and first to

third stations

1823, 1825, and 1827 connected to the AP 1821. Include. The devices belonging to the wireless network A 1820 communicate at a maximum transmit power of 100 kHz on channel 22 of the TVWS channel map 1810.

Meanwhile, the wireless network B 1830 includes an AP 1831 managing the wireless network, a first station 1833 and a second station 1835 connected to the AP. The devices belonging to the wireless network B 1830 communicate with a maximum transmit power of 40 kHz on channel 17 of the TVWS channel map 1810.

Referring to FIG. 27, a second station 1825 belonging to the wireless network A 1820 requests information about a neighbor network 1830 from the AP 1921 to move to a new place. At this time, the second station 1825 transmits a neighbor report request frame 1840 to the AP 1821.

The AP 1821 analyzes the received neighbor report request frame 1840 to identify the neighbor network 1830 requested by the second station 1825.

Meanwhile, the AP 1821 collects information on wireless networks in the vicinity, creates a neighbor network list, and periodically updates and manages the neighbor network list.

The AP 1821 may know information about an operating channel of the neighbor network 1830 requested by the second station 1825 using the neighbor network list. For example, based on the neighbor network list, the AP 1821 may determine that devices belonging to the neighbor network 1830 are operating at a maximum transmit power of 40 kHz on channel 17. FIG.

Thereafter, the AP 1821 transmits a neighbor report response frame 1850 including information about the neighbor network 1830 to the second station 1825.

In particular, the neighbor report response frame 1850 may include an operating class and a behavior limits set proposed by the present invention, thereby causing the second station 1825 to determine a neighbor network 1830 of the neighbor network 1830. Allows you to identify information about operating channels.

The neighbor report request frame 1840 transmitted to the second station 1825 and the neighbor report response frame 1850 transmitted by the AP 1821 will be described in detail as follows.

FIG. 28 shows a structure of a neighbor report request frame transmitted by a station operating in the TVWS to request information about a neighbor network. Here, the neighbor report request frame transmitted by the station is configured using the neighbor report request frame defined in IEEE 802.11k.

Referring to FIG. 28, the neighbor report request frame 1900 includes a Category field 1901, an Action field 1903, a Dialog Token field 1905, and an Optional Subelements field 1907.

The Category field 1901 indicates a category of the corresponding frame, and the Action field 1903 indicates that the frame is a neighbor report request frame.

The Dialog Token field 1905 is a field into which a value selected by a device transmitting a corresponding frame is inserted to identify a frame exchange between an AP and stations.

The Optional Subelements field 1907 includes a Subelement ID field 1909, a Length field 1911, and a Data field 1913.

The Subelement ID field 1909 is a field for inserting an identifier for indicating a subelement such as 'Service Set ID (SSID)' or 'Vendor Specific'. For example, in the present embodiment, the second station 1825 sets the Subelement ID field 1909 of the neighbor report request frame 1900 to "00x0" to indicate that the subelement is an SSID. In this case, the SSID is an identifier of a wireless network and includes a concept of an extended service set (ESSID) and a basic service set ID (BSSID).

The Length field 1911 indicates the length of the corresponding information element, and the Data field 1913 includes information on the subelement. For example, in the present embodiment, the second station 1825 stores and transmits the "SSID" of the wireless network B 1830 in the DATA field 1913 of the neighbor report request frame 1900.

FIG. 29 illustrates a structure of a neighbor report response frame transmitted by an AP operating in TVWS to report information on a neighbor network. Here, the neighbor report response frame transmitted by the AP is configured using the neighbor report response frame defined in IEEE 802.11k.

Referring to FIG. 29, the neighbor report response frame 2000 includes a Category field 2001, an Action field 2003, a Dialog Token field 2005, and a Neighbor Report Elements field 2009.

The Category field 2001 indicates a category of the corresponding frame, and the Action field 2003 indicates that the frame is a neighbor report response frame.

The Dialog Token field 2005 is a field into which a value selected by a device transmitting a corresponding frame is inserted to identify a frame exchange between an AP and stations.

The Neighbor Report Elements field 2009 includes an Element ID field 2009, a Length field 2011, a BSSID field 2013, a BSSID Information field 2015, an Operating Class field 2017, a Channel Number field 2019, and a PHY. It includes a Type field 2021 and an Optional Subelements field 2023.

The Element ID field 2009 indicates an identifier (ID) of the neighbor report element, and the Length field 2011 indicates a length of the neighbor report element.

The BSSID field 2013 indicates an identifier of a wireless network to report. For example, in the present embodiment, the AP 1821 sets and transmits the BSSID field 2013 as an identifier of the wireless network B. The BSSID Information field 2015 indicates information on other wireless networks in the vicinity.

The Operating Class field 2017 is a field into which an index of an operating class including information about an operating channel of a neighboring network is inserted. Here, the index of the operation class may be selected from any of the operation classes of Table 2 proposed in the present invention.

For example, in the present embodiment, the AP 1821 sets the Operating Class field 2017 to '41' and transmits it. Then, the second station 1821 may know the channel definition method (Center on center) and the channel bandwidth (10MHz) used by the wireless network B 1830 through the received Operating Class field 2017. In addition, the second station 1821 may know that a TV signal exists in an adjacent channel of a channel in which devices belonging to the wireless network B 1830 are operating.

The Channel Number field 2019 indicates a channel number used in the requested wireless network. For example, in the present embodiment, the AP 1821 sets the Channel Number field 2019 to '17' and transmits it. Then, the second station 1821 may know that the wireless network B 1830 is using channel 17 through the received Channel Number field 2019.

The PHY Type field 2021 indicates a physical layer type of an AP indicated by the BSSID. The Optional Subelements field 2023 includes a Subelement ID field (not shown), a Length field (not shown), and a Data field (not shown). On the other hand, since the description of the fields has already been mentioned in FIG. 28, it will be omitted below.

Referring again to FIG. 27, the second station 1825 receives a neighbor report response frame 1850 including information about a neighbor network from the AP 1821.

The second station 1825 analyzes the Channel Number field 2019 of the neighbor report response frame 1850 to find out the channel number being used by the wireless network B 1830. In addition, the second station 1825 analyzes the Operation Class field 2017 of the neighbor report response frame 1850 to determine whether a TV signal exists in a channel adjacent to the channel being used by the wireless network B 1830. Check whether or not.

Thereafter, the second station 1825 moves to the area of the wireless network B 1830 based on the information obtained from the AP. The second station 1825 performs a network connection with the AP 1831 managing the corresponding network 1830. For example, in the present embodiment, the second station 1825 performs a connection operation with a maximum transmit power of 40 kW using channel 17.

30 illustrates a procedure of a station belonging to a wireless network to identify information about a neighbor network using a neighbor report request frame and a neighbor report response frame.

Referring to FIG. 30, in step 2110, APs and stations existing in a wireless network perform communication using a specific channel.

In step 2120, the station intending to move to a new place transmits a neighbor report request frame to the corresponding AP to obtain information about the neighbor network. Then, in step 2130, the AP transmits a neighbor report response frame corresponding to the neighbor report request frame. That is, the station receives a neighbor report response frame including information about the neighbor network from the AP.

In step 2140, the station analyzes the Channel Number field of the neighbor report response frame to find out the channel number being used in the neighbor network.

In step 2150, the station analyzes the Operation Class field of the neighbor report response frame to determine whether the operation class of the corresponding channel defines the neighbor channel behavior restriction. That is, it is determined whether a TV signal exists in an adjacent channel of a channel being used by the neighboring network.

As a result of the check, if the operation class defines the adjacent channel behavior restriction, the control proceeds to step 2160. In step 2160, the station moves to the neighbor network. Next, the station moves to step 2170 to attempt network connection with the AP managing the neighbor network. At this time, the station initiates a connection operation with a maximum transmit power of 40 kW using the channel acquired in step 2140.

On the other hand, if the check result, the action class does not define the adjacent channel behavior restriction, go to step 2180. In operation 2180, the station moves to the neighbor network. Next, the station moves to step 2190 and attempts a network connection with the AP managing the neighbor network. At this time, the station starts a connection operation with a transmission power of up to 100 kHz using the channel obtained in step 2140.

Through the above-described steps, the station can identify the presence of behavior limits for the neighboring channel and the operation channel of the neighboring network using the received neighbor report response frame.

31 is a block diagram illustrating a structure of wireless LAN devices in which embodiments of the present invention can be implemented.

Referring to FIG. 31, the wireless LAN devices include an AP 2200 and a station 2250, and the AP 2200 and the station 2250 respectively include a

controller

2205 and 2255, and an

RF transceiver

2210 and 2260. ), PHY units 2215 and 2275 and

MAC units

2220 and 2270. Meanwhile, the AP 2200 may further include a channel manager 2225, an IP protocol unit 2230, and a location identifier 2235 in addition to the components.

The

RF transceiver

2210 and 2260 converts a signal input from the PHY units 2215 and 2275 as physical layers into an RF frequency, and then performs filtering and / or amplification to transmit the signal through an antenna. In addition, the

RF transceiver

2210 and 2260 converts the RF signal received from the antenna into a signal that can be processed by the PHY units 2215 and 2275 through filtering and the like. On the other hand, the

RF transceiver

2210, 2260 may include a switch function for switching the transmission and reception of the signal.

The PHY units 2215 and 2275 perform Forward Error Correction (FEC) encoding and modulation on data requested from the

MAC units

2220 and 2270 which are MAC (Media Access Control) layers, and preamble and pilot. It performs a process of adding a signal such as a pilot and the like and delivers the signal to the

RF transceivers

2210 and 2260.

In addition, the PHYs 2215 and 2275 perform demodulation, equalization, and FEC decoding on the signals received through the

RF transceivers

2210 and 2260, and remove the preamble and pilot signals added by the transmitter. It performs the process of delivering to the MAC unit (2220, 2270). For this operation, the PHY units 2215 and 2275 may include a modulator, a demodulator, an equalizer, an FEC encoder, a FEC decoder, and the like. .

The

MAC units

2220 and 2270 process data transmitted from an upper layer, that is, data requested to be transmitted, and output the processed data to the PHY units 2215 and 2275 and perform additional transmissions for the data transfer. In charge.

In addition, the

MAC units

2220 and 2270 process received data input from the PHY units 2215 and 2275 to the upper layer, and are in charge of additional transmissions required for the data transfer.

The IP protocol unit 2230 processes the data input from the upper layer and transfers it to the

MAC units

2220 and 2270, and processes the data input from the

MAC units

2220 and 2270. It delivers to the upper layer.

The location identification unit 2235 performs an overall operation for checking its location. The channel manager 2225 accesses the geographic location database using its location information identified through the location identifier 2235, and acquires a TVWS channel list available at the corresponding location. In addition, the channel manager 2225 selects at least one channel from the acquired TVWS channel list, and performs an operation of initiating a wireless network in the corresponding channel.

The

controllers

2205 and 2255 control the RF transceivers 2215 and 2275, the PHY units 2215 and 2275, and the

MAC units

2220 and 2270 to perform respective functions according to control signals transmitted from higher layers. do. In addition, the

controllers

2205 and 2255 may be configured to smoothly control processing such as requests and processing time points between the RF transceivers 2215 and 2275, the PHY units 2215 and 2275, and the

MAC units

2220 and 2270. Perform adjustment and management functions.

In addition, the

controllers

2205 and 2255 serve to control an operation for performing the channel identification method according to the present invention. For example, the

controllers

2205 and 2255 may control a process of generating a frame including information on an operation class and a channel number and signaling the same.

The AP 2200 and the station 2250 including these components perform the channel information identification method according to the above-described first to fourth embodiments through a signaling process.

For example, the AP 2200 transmits a radio measurement request frame for requesting information on another TVWS channel to a specific station, and uses the TVWS channel by using a radio measurement report frame received in response to the radio measurement request frame. An operation for identifying the information about is described in detail.

The controller 2205 generates a radio measurement request frame to request a specific station to perform radio measurement on another TVWS channel. At this time, the controller 2205 may generate the radio measurement request frame by controlling the MAC unit 2220 and the PHY unit 2215. The radio measurement request frame generated by the controller 2205 includes information about an address and a channel number of the specific station.

The MAC unit 2220 processes the data transmitted from the upper layer under the control of the controller 2205, that is, the data requested to be transmitted, and then outputs the processed data to the PHY unit 2215. Here, the data is information on the address and channel number of the specific station.

The PHY unit 2215 performs FEC (Forward Error Correction) encoding and modulation on the data requested to be transmitted from the MAC unit 2220, which is a media access control (MAC) layer. Thereafter, the PHY unit 2215 generates a frame by performing a process such as adding a signal such as a preamble and a pilot to the modulated signal, and transmits the generated frame to the RF transceiver 2210. It plays a role.

The RF transceiver 2210 converts a frame input from the PHY unit 2215, which is a physical layer, into an RF frequency, and then filters and / or amplifies a frame to be transmitted through an antenna. At this time, the frame transmitted by the antenna is a radio measurement request frame.

The AP 2200 may receive a radio measurement report frame corresponding to the radio measurement request frame from the specific station.

That is, the RF transceiver 2210 converts the RF signal received through the antenna into a digital signal that can be processed by the PHY unit 2215 through filtering or the like.

The PHY unit 2215 performs demodulation, equalization, and FEC decoding on the frame received through the RF transceiver unit 2210 and removes the added preamble and pilot signal, thereby performing data bits. Outputs Thereafter, the PHY unit 2215 transfers the output data bits to the MAC unit 2220. The MAC unit 2220 processes the received data input from the PHY unit 2215 and transfers the received data to a higher layer. . Here, the data is information on whether a primary user exists in the specific channel and whether the primary user causes behavior limitation in an adjacent channel.

The controller 2205 may control operations of the MAC unit 2220, the PHY unit 2215, and the RF transceiver 2210 to obtain corresponding information from the radio measurement report frame. That is, the controller 2205 may identify the information on the corresponding channel by analyzing the received radio measurement report frame.

Meanwhile, the station 2250 transmits a radio measurement report frame including information on an operation channel, and uses the extended channel change notification frame received from the AP 2200 to a channel to be newly moved in the operation channel. An operation for identifying information about the operation will be described in detail.

The controller 2255 checks whether a primary user is detected in an operation channel of a wireless network. If the primary user is detected in the wireless network, the controller 2255 generates a radio measurement report frame including information about the primary user. In this case, the controller 2255 may control the MAC unit 2270 and the PHY unit 2265 to generate a radio measurement report frame. In addition, the radio measurement report frame generated by the controller 2205 includes information on the presence or absence of the primary user and information on whether the primary user causes a behavior restriction on an adjacent channel.

The MAC unit 2270 processes the data transmitted from the upper layer, that is, the data requested to be transmitted, under the control of the controller 2255, and outputs the data to the PHY unit 2265. Here, the data includes information on the presence or absence of the primary user and information on whether or not the primary user causes behavior limitation in the adjacent channel.

The PHY unit 2265 performs Forward Error Correction (FEC) encoding and modulation on data requested to be transmitted from the MAC unit 2270, which is a media access control (MAC) layer. Thereafter, the PHY unit 2265 generates a frame by performing a process such as adding a signal such as a preamble and a pilot to the modulated signal, and transmits the generated frame to the RF transceiver 2260. It plays a role.

The RF transceiver 2260 converts a frame input from the PHY unit 2265, which is a physical layer, into an RF frequency, and then performs filtering and / or amplification to transmit a frame through an antenna. At this time, the frame transmitted by the antenna is a radio measurement report frame.

Thereafter, the station 2250 may receive from the AP 2200 an extended channel switching notification frame including information on a channel to be newly moved in the operation channel.

That is, the RF transceiver 2260 converts the RF signal received through the antenna into a digital signal that can be processed by the PHY unit 2265 through filtering or the like.

The PHY unit 2265 performs demodulation, equalization, and FEC decoding on the frame received through the RF transceiver 2260, and removes the added preamble and pilot signal, thereby performing data bits. Outputs Thereafter, the PHY unit 2265 transfers the output data bit to the MAC unit 2270.

The MAC unit 2270 processes the received data input from the PHY unit 2265 and delivers the received data to a higher layer. Here, the data includes information about a channel number and an operation class of the null to be moved.

The controller 2255 may control operations of the MAC unit 2270, the PHY unit 2265, and the RF transceiver 2260 to obtain corresponding information from the extended channel switching notification frame. That is, the controller 2255 may identify the information about the channel to move by analyzing the received extended channel announcement frame.

At least some of the above-described method for identifying channel information according to an embodiment of the present invention may be stored in a computer-readable recording medium that is produced as a program to be executed in a computer. ROMs, RAMs, CD-ROMs, magnetic tapes, floppy disks, optical data storage devices, and the like, and also include those implemented in the form of carrier waves (eg, transmission over the Internet).

The computer readable recording medium can be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion. In addition, functional programs, codes, and code segments for implementing the method can be easily inferred by programmers in the art to which the present invention belongs.

On the other hand, while the specific embodiments of the present invention have been described, various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined not only by the claims below, but also by those equivalent to the claims.

That is, the detailed description of the above-described invention shows an implementation example applied to a wireless LAN system using a TV white space. However, the present invention can be applied to other wireless communication systems using similar technical backgrounds and TV white spaces without departing from the scope of the present invention, which can be determined by those skilled in the art. It will be possible.

Claims

In a wireless LAN system comprising an access point (AP) for managing a wireless network and at least one station connected to the AP, in the channel information identification method of the station,

Checking whether a primary user is detected in an operating channel of the wireless network;

Transmitting a first frame including information about the primary user to the AP;

Receiving a second frame including information on a channel to be moved in the operation channel from the AP; And

And analyzing the received second frame to identify the channel information to be moved.
The method of claim 1,

And the primary user is a TV broadcast service or a wireless microphone signal.
The method of claim 1,

And wherein said AP and said at least one station operate in a TV white space.
The method of claim 1,

And the first frame is a radio measurement report frame.
The method of claim 1,

And the first frame includes information on the presence or absence of the primary user and information on whether the primary user causes a behavior restriction on an adjacent channel.
The method of claim 1,

And the second frame is any one of an extended channel change notification frame, a beacon frame, and a probe response frame.
The method of claim 1,

And the second frame includes information on a channel number and an operation class of the channel to be moved.
The method of claim 7, wherein

And the operation class includes information on whether a TV broadcast service exists in an adjacent channel of the channel to be moved.
The method of claim 1,

Initiating communication at a maximum transmit power defined according to the identified channel information.
In a wireless LAN system comprising an access point (AP) for managing a wireless network and at least one station connected to the AP, in the channel information identification method of the AP,

Sending a first frame to the at least one station requesting measurement for a particular channel;

Receiving a second frame from the at least one station, the second frame comprising information on whether a primary user exists in the particular channel and whether the primary user causes behavior limitation in an adjacent channel; And

Analyzing the received second frame to identify information for the particular channel.
The method of claim 10,

And the first frame is a radio measurement request frame.
The method of claim 10,

And the second frame is a radio measurement report frame.
The method of claim 10,

To move the wireless network from the current channel to the specific channel,

And transmitting a third frame including information on the specific channel to all stations belonging to the wireless network.
The method of claim 13,

And the third frame is any one of an extended channel change notification frame, a beacon frame, and a probe response frame.
The method of claim 13,

And wherein the third frame includes information on a channel number and an operation class of the specific channel.
The method of claim 15,

And the operation class includes information on whether a TV broadcast service exists in an adjacent channel of the specific channel.
In a wireless LAN system comprising an access point (AP) for managing a wireless network and at least one station connected to the AP, the channel information identification method of the station to move to the area of the neighbor network,

Transmitting a first frame requesting information about the neighbor network to the AP;

Receiving a second frame including information on an operation channel number and an operation class of the neighboring network, from the AP; And

Analyzing the received second frame to identify information about an operating channel of the neighboring network.
The method of claim 17,

Wherein the first frame is a neighbor report request frame, and the second frame is a neighbor report response frame.
The method of claim 17,

And the operation class includes information on whether a TV broadcast service exists in an adjacent channel of the operation channel.
The method of claim 17,

Moving to the neighboring network and initiating communication at a maximum transmit power defined according to the identified channel information.