KR101561115B1 - Method for scanning access point in wireless local area network system - Google Patents

Abstract

A method for searching an access point in a wireless LAN system is disclosed. An active search method includes transmitting a probe request frame to an access point, and receiving a probe response frame corresponding to a probe request frame from an access point, wherein the probe response frame includes a beacon transmitted after the probe response frame The time information of the time stamp. Therefore, the efficiency of the wireless channel in the wireless LAN system can be improved.

Description

METHOD FOR SCANNING ACCESS POINT IN WIRELESS LOCAL AREA NETWORK SYSTEM [0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention [0002] The present invention relates to a method of searching an access point, and more particularly, to a searching method of an access point using an active search method in a wireless LAN system.

With the development of information and communication technology, various wireless communication technologies are being developed. Among these, a wireless local area network (WLAN) is a wireless local area network (WLAN) based on radio frequency technology such as a personal digital assistant (PDA), a laptop computer, a portable multimedia player It is a technology that allows a portable terminal to access the Internet wirelessly in a home, a business, or a specific service providing area.

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

As the spread of the WLAN is activated and the applications using the WLAN are activated, a need for a new WLAN technology to support a higher throughput than the data processing speed supported by IEEE 802.11n is increasing. Very high throughput (VHT) Wireless LAN technology is one of the proposed IEEE 802.11 wireless LAN technologies to support data rates of more than 1 Gbps. Among them, IEEE 802.11ac is being developed as a standard for providing ultra high throughput in a band below 6 GHz, and IEEE 802.11ad is being developed as a standard for providing ultra high throughput in the 60 GHz band.

In a system based on such a wireless LAN technology, there are an active scan method and a passive scan method as an access point search method.

An active access method of an access point is a method in which a station transmits a probe request frame and an access point that receives the probe request frame responds with a probe response frame. Generally, the probe response frame contains a lot of information and occupies the wireless channel for a long time.

In an environment where a plurality of access points and terminals exist, a probe request frame of each terminal causes a considerable number of probe response frames to be generated, and these probe response frames occupy wireless channels while competing with each other. This makes it difficult for the terminal to receive the probe response frame from the desired access point in a short period of time and keep awake while receiving the probe response frame of the unwanted access point in order to receive the desired probe response frame.

In addition, since the terminal does not know which channel the desired access point exists, the access point search process described above should be sequentially performed for each channel. At this time, the terminal waits long enough for receiving the probe response frame of the desired access point Move to another channel.

That is, there is a problem that a long time is consumed to receive the probe response frame of the desired access point in the active search method of the access point.

It is an object of the present invention to provide an active search method performed by a mobile station for performing active search using a probe response frame including only information necessary for searching for an access point.

Another object of the present invention is to provide an active search method performed in an access point for performing an active search using a probe response frame including only information necessary for searching for an access point .

According to an aspect of the present invention, there is provided an active search method performed by a terminal, the method comprising: transmitting a probe request frame to an access point; and transmitting a probe response frame corresponding to the probe request frame from the access point Wherein the probe response frame includes time information of a beacon transmitted from the access point after the probe response frame.

Here, the active search method may further include receiving a beacon from the access point at a time indicated by the time information of the beacon.

Here, the terminal may operate in a power saving mode for a time from the reception of the probe response frame until the time indicated by the time information of the beacon.

Here, the terminal may perform a search for an access point in another channel for a period of time from the reception of the probe response frame until the time point indicated by the time information of the beacon.

Here, the time information may include time information until the beacon is transmitted.

Here, the time information may include time information of the beacon transmission.

Here, the time information may include time information of a next full beacon or time information of a next short beacon.

Here, the probe response frame may be a short probe response frame.

According to another aspect of the present invention, there is provided an active access response method of an access point, comprising: receiving a probe request frame from a terminal; generating a probe response frame in response to the probe request frame; And transmitting the probe response frame to the terminal, wherein the probe response frame includes time information of a beacon transmitted after the probe response frame.

Here, the active search response method may further include transmitting a beacon at a time indicated by the beacon time information.

Here, the time information may include time information until the beacon is transmitted.

Here, the time information may include time information of the beacon transmission.

Here, the time information may include time information of a next full beacon or time information of a next short beacon.

Here, the probe response frame may be a short probe response frame.

According to the present invention, by using the probe response frame (i.e., the short probe response frame or the probe ACK) including the information necessary for searching the access point, the time occupied by the wireless channel by the probe response frame can be reduced, Can be improved.

Also, the terminal can know the transmission time of the beacon through the time information of the next beacon included in the probe response frame, and can search for the access point on another channel before transmission of the next beacon based on the information. You can reduce the time spent searching.

1 is a conceptual diagram showing an embodiment of a configuration of an IEEE 802.11 wireless LAN system.
2 is a conceptual diagram illustrating a connection procedure of a terminal in an infrastructure BSS.
3 is a conceptual diagram showing an embodiment of a data transmission process of an access point.
4 is a conceptual diagram illustrating an active search method in multiple channels.
5 is a conceptual diagram showing a manual search method in a multi-channel.
6 is a flowchart illustrating an active search method according to an embodiment of the present invention.
7 is a conceptual diagram illustrating an active search method according to an embodiment of the present invention.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail.

It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component. And / or < / RTI > includes any combination of a plurality of related listed items or any of a plurality of related listed items.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, . On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the relevant art and are to be interpreted in an ideal or overly formal sense unless explicitly defined in the present application Do not.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In order to facilitate the understanding of the present invention, the same reference numerals are used for the same constituent elements in the drawings and redundant explanations for the same constituent elements are omitted.

Throughout the specification, a station is a physical layer for medium access control (MAC) and a medium access control (MAC) compliant with the IEEE 802.11 standard. Means any functional medium including an interface. A station (STA) can be divided into a station (STA) which is an access point (AP) and a station (STA) which is a non-AP. A station (STA), which is an access point (AP), may be referred to simply as an access point (AP), and a station (STA) that is a non-AP may be simply referred to as a terminal.

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

An access point (AP) may refer to a centralized controller, a base station (BS), a node-B, an eNode-B, a base transceiver system (BTS), a site controller, May include some or all of the functions of the < / RTI >

A terminal may be a wireless transmit / receive unit (WTRU), a user equipment (UE), a user terminal (UT), an access terminal (AT), a mobile station May refer to a mobile terminal, a subscriber unit, a subscriber station (SS), a wireless device, or a mobile subscriber unit, Or all functions.

Here, a desktop computer, a laptop computer, a tablet PC, a wireless phone, a mobile phone, a smart phone, an e- a book reader, a portable multimedia player (PMP), a portable game machine, a navigation device, a digital camera, a digital multimedia broadcasting (DMB) player, a digital audio recorder, a digital audio player A digital picture recorder, a digital picture player, a digital video recorder, a digital video player, or the like can be used.

1 is a conceptual diagram showing an embodiment of a configuration of an IEEE 802.11 wireless LAN system.

Referring to FIG. 1, an IEEE 802.11 WLAN system includes at least one basic service set (BSS). A BSS is a set of stations (STA 1, STA 2 (AP 1), STA 3, STA 4, STA 5 (AP 2)) that are able to successfully communicate and communicate with each other, no.

The BSS can be divided into an infrastructure BSS (infrastructure BSS) and an independent BSS (IBSS), and BSS 1 and BSS 2 mean an infrastructure BSS. The BSS 1 connects the access point STA 2 (AP 1) and the access points STA 2 (AP 1) and STA 5 (AP 2), which provide a terminal STA 1, a distribution service And a distribution system (DS). In BSS 1, the access point (STA 2 (AP 1)) manages the terminal (STA 1).

The BSS 2 is connected to a plurality of access points (STA 3 and STA 4), an access point (STA 5 (AP 2)) and a plurality of access points (STA 2 (AP 1) and STA 5 Distribution system. In BSS 2, the access point (STA 5 (AP 2)) manages the terminals STA 3 and STA 4.

Meanwhile, the independent BSS is a BSS operating in an ad-hoc mode. Since the IBSS does not include an access point, there is no centralized management entity in the center. That is, terminals in the IBSS are managed in a distributed manner. In the IBSS, all terminals can be made as mobile terminals, and self-contained networks can be established because access is not allowed to the distribution system (DS).

The access points STA 2 (AP 1) and STA 5 (AP 2) provide a connection to the distributed system (DS) over the wireless medium for the terminal (STA 1, STA 3, STA 4) . The communication between the terminals STA 1, STA 3 and STA 4 in the BSS 1 or BSS 2 is generally performed through the access points STA 2 (AP 1) and STA 5 (AP 2) link is established, direct communication between the terminals STA 1, STA 3 and STA 4 is possible.

A plurality of infrastructure BSSs may be interconnected via a distribution system (DS). A plurality of BSSs connected through a distribution system (DS) is referred to as an extended service set (ESS). The stations included in the ESS can communicate with each other, and within the same ESS, the UE can move from one BSS to another while seamlessly communicating.

The distribution system DS is a mechanism by which one access point communicates with another access point. According to this, the access point transmits a frame for terminals connected to the BSS that it manages, or moves to another BSS A frame can be transmitted for an arbitrary terminal. The access point can also transmit and receive frames to and from an external network, such as a wired network. Such a distribution system (DS) does not necessarily have to be a network, and there is no restriction on the form if it can provide a predetermined distribution service defined in the IEEE 802.11 standard. For example, the distribution system may be a wireless network, such as a mesh network, or may be a physical structure that connects the access points to each other.

The access point search method according to an embodiment of the present invention can be applied to the IEEE 802.11 wireless LAN system described above. In addition to the IEEE 802.11 wireless LAN system, a wireless personal area network (WPAN), a wireless body area Network), and the like.

2 is a conceptual diagram illustrating a connection procedure of a terminal in an infrastructure BSS.

In order for a terminal STA to transmit and receive data in an intra-architecture BSS, a terminal STA must first be connected to an access point (AP).

Referring to FIG. 2, the connection procedure of the STA in the infrastructure BSS includes 1) a probe step of detecting an access point (AP), 2) an authentication step with an access point (AP) ), And 3) an association step with an authenticated access point (AP).

The terminal STA may first detect neighboring APs through a detection process. The detection process is classified into a passive scanning method and an active scanning method. The passive scanning method may be performed by overhearing beacons transmitted by neighboring access points (APs). Meanwhile, the active scanning method may be performed by broadcasting a probe request frame. The access point (AP) receiving the probe request frame can transmit a probe response frame corresponding to the probe request frame to the corresponding STA. The terminal STA can know the existence of neighboring APs by receiving the probe response frame.

Thereafter, the terminal STA performs authentication with the detected access point (AP) and can perform authentication with the detected plurality of access points (APs). The authentication algorithm according to the IEEE 802.11 standard is divided into an open system algorithm for exchanging two authentication frames and a shared key algorithm for exchanging four authentication frames. The STA can perform authentication with an access point (AP) through a process of exchanging an authentication request frame and an authentication response frame based on the authentication algorithm.

Finally, the terminal STA selects one access point AP among the plurality of authorized access points APs and performs a connection process with the selected access point AP. That is, the STA transmits an association request frame to a selected access point (AP), and an access point (AP) receiving the connection request frame transmits an association response frame corresponding to the connection request frame frame to the corresponding STA. In this manner, the STA can perform a connection process with the access point (AP) through the process of exchanging the connection request frame and the connection response frame.

3 is a conceptual diagram showing an embodiment of a data transmission process of an access point.

Referring to FIG. 3, an access point (AP) periodically broadcasts a beacon, and can broadcast a beacon including DTIM at three beacon intervals. The terminal (STA 1, STA 2) of the power save mode (PSM) periodically wakes up (awake) to receive the beacon, checks the TIM or DTIM included in the beacon, Make sure it is buffered. At this time, if buffered data exists, the terminals STA1 and STA2 keep awake and receive data from the access point (AP). If there is no buffered data, the terminals STA1 and STA2 ) Returns to the power saving state (i.e., the doze state).

That is, when the bit in the TIM corresponding to the AID of the mobile station AID is set to 1, the terminal STA 1 and STA 2 transmit a PS (Power Save) -Poll frame (not shown) Or a trigger frame) to the access point (AP), and the access point (AP) confirms that the terminal (STA 1, STA 2) is ready for data reception by receiving the PS-Poll frame, And may transmit data or ACK (acknowledgment) to the terminals STA 1 and STA 2. When the ACK is transmitted to the terminals STA 1 and STA 2, the access point AP transmits the data to the terminals STA 1 and STA 2 at an appropriate time. On the other hand, when the bit in the TIM corresponding to the own AID is set to 0, the terminals STA 1 and STA 2 return to the power saving state.

4 is a conceptual diagram illustrating an active search method in multiple channels.

Referring to FIG. 4, a UE may first transmit a probe request frame on a channel 1 to a specific access point or all access points, and may receive a probe response frame transmitted from an access point during a maximum waiting time . That is, the terminal can receive the probe response frame 1 from the access point 1 during the maximum waiting time on the channel 1, receive the probe response frame 2 from the access point 2, and receive the probe response frame 3 from the access point 3 can do.

After the maximum waiting time on channel 1, the terminal can go to channel 2 to send a probe request frame to a specific access point or all access points, and to receive a probe response frame transmitted from the access point for a maximum waiting time have. That is, the terminal can receive the probe response frame 4 from the access point 4, receive the probe response frame 5 from the access point 5, receive the probe response frame 6 from the access point 6 can do.

5 is a conceptual diagram showing a manual search method in a multi-channel.

Referring to FIG. 5, a UE can receive beacons transmitted from an access point in Channel 1, and a UE can move to Channel 2 after a beacon interval in Channel 1. Then, in channel 2, the terminal can receive beacons transmitted from the access point.

6 is a flowchart illustrating an active search method according to an embodiment of the present invention.

Referring to FIG. 6, the terminal 10 may first transmit a probe request frame to the access point 20 (S100). Here, the terminal 10 can transmit a probe request frame specifying an access point or transmit a probe request frame to an unspecified access point (i.e., all access points). On the other hand, the terminal 10 can make a request for providing time information of the next beacon through a probe request frame. That is, the terminal 10 can set an arbitrary field indicating a request for providing time information of the next beacon, and can generate a probe request frame including the beacon and transmit it to the access point.

When receiving the probe request frame from the terminal 10, the access point 20 can generate a probe response frame including time information of the next beacon (S110). That is, the access point 20 may generate the probe response frame including the time information of the beacon transmitted after transmission of the probe response frame. The access point 20 may generate a probe response frame that includes the time information of the next full beacon or the time information of the next short beacon (i.e., auxiliary beacon).

Here, the full beacon means a beacon commonly used in a wireless LAN system (IEEE 802.11). The short beacon is used for speed up the manual search, and means a beacon having a shorter period than the full beacon and containing only the essential information for searching.

For example, the short beacon includes timestamp information, change sequence information, time of next full beacon information, compressed SSID (service set identifier) information, Access network options information, and the like.

The time information of the next beacon may be a duration to next beacon or a time at which the next beacon is transmitted (i.e., target beacon transmission time (TBTT)).

That is, the access point 20 may generate a new probe response frame (i.e., a short probe response frame or a probe ACK frame) that replaces the existing probe response frame. The new probe response frame may have a smaller size than the existing probe response frame, and the new probe response frame may include SSID as essential information for searching, time information of the next beacon (i.e., beacon transmitted after transmission of the probe response frame Time information).

The access point 20 may transmit a probe response frame including time information of the beacon to the terminal 10 (S120).

When receiving the probe response frame from the access point 20, the terminal 10 can acquire time information of the next beacon (i.e., time information of the beacon transmitted after transmission of the probe response frame) from the probe response frame (S130). When the time information of the next beacon indicates a period during which the next beacon is transmitted, the terminal 10 can acquire a time point at which the next beacon is transmitted based on the current time and the period during which the next beacon is transmitted.

The terminal 10 may return to a sleep state (i.e., a power saving mode) until the next beacon is transmitted, or may return to a sleep state Can be performed.

The access point 20 can transmit a beacon at a time indicated by the time information of the next beacon included in the probe response frame (S140). Here, the access point 20 can transmit a full beacon or a short beacon. The terminal 10 can receive the beacon at the time indicated by the time information of the next beacon included in the probe response frame.

7 is a conceptual diagram illustrating an active search method according to an embodiment of the present invention.

Referring to FIG. 7, the UE can first transmit a probe request frame on channel 1, and can receive a response for a maximum waiting time. That is, the terminal can receive probe response frame 1 (i.e., probe ACK 1) from access point 1 during the maximum waiting time on channel 1 and receive probe response frame 2 (i.e., probe ACK 2) from access point 2 And can receive the probe response frame 3 (i.e., probe ACK 3) from the access point 3.

Here, the probe response frames 1 to 3 mean probe response frames including time information of the next beacon described in FIG. That is, since the probe response frames 1 to 3 have a size smaller than that of the conventional probe response frame, the maximum waiting time in the channel 1 can be set shorter than the existing maximum waiting time.

When the probe response frame transmitted during the maximum waiting time in channel 1 is received, the terminal can determine the access target access point based on the signal strength of the probe response frame. That is, the terminal can determine the access point that transmitted the probe response frame having the largest signal strength among the probe response frames 1 to 3 as the connection target access point, or the signal strength among the probe response frames 1 to 3 satisfies the predetermined criterion It is possible to determine the access point that transmitted the probe response frame as the connection target access point.

For example, when the signal strength of the probe response frame 1 is the largest, the terminal can determine the access point 1 as a connection target access point, and based on the time information of the next beacon included in the probe response frame 1, It is possible to acquire the transmission time point of the next auxiliary beacon (aux. Beacon 1) (i.e., short beacon 1). Here, the terminal can determine to receive the beacon at the transmission time of the next beacon 1.

The terminal can search for an access point in another channel if the time until the transmission time of the next beacon 1 (i.e., time for searching for an access point on another channel) remains. That is, the UE moves to channel 2 and can transmit a probe request frame. The terminal can receive probe response frame 4 (i.e., probe ACK 4) from access point 4 during the maximum waiting time on channel 2 and receive probe response frame 5 (i.e., probe ACK 5) from access point 5 , And can receive the probe response frame 6 (i.e., probe ACK 6) from the access point 6.

Here, the probe response frames 4 to 6 mean the probe response frames including the time information of the next beacon described in FIG. That is, since the probe response frames 4 to 6 have a size smaller than that of the conventional probe response frame, the maximum waiting time in the channel 2 can be set shorter than the existing maximum waiting time.

When receiving the probe response frame transmitted during the maximum waiting time in channel 2, the terminal can determine the access target access point based on the signal strength of the probe response frame. For example, when the signal strength of the probe response frame 6 is the largest among the probe response frames 4 to 6, the terminal can determine the access point 6 as the connection target access point, and the time information of the next beacon included in the probe response frame 6 The transmission time point of the next beacon 6 or the next auxiliary beacon 6 can be obtained. Here, the terminal can decide to receive the beacon at the transmission time of the next beacon 6.

If there is sufficient time until the transmission time point of the next beacon 1 (i.e., time for searching for an access point on another channel), the terminal can search for the access point on another channel. That is, the UE moves to channel 3 and can transmit a probe request frame. The terminal can receive probe response frame 7 (i.e., probe ACK 7) from access point 7 during the maximum wait time on channel 3 and receive probe response frame 8 (i.e., probe ACK 8) from access point 8 And can receive the probe response frame 9 (i.e., probe ACK 9) from the access point 9.

Here, the probe response frames 7 to 9 refer to the probe response frames including the time information of the next beacon described with reference to FIG. That is, since the probe response frames 7 to 9 have a size smaller than that of the conventional probe response frame, the maximum waiting time in the channel 3 can be set shorter than the existing maximum waiting time.

When the probe response frame transmitted during the maximum waiting time in channel 3 is received, the terminal can determine the access target access point based on the signal strength of the probe response frame. For example, when the signal strength of the probe response frame 9 is the largest among the probe response frames 7 to 9, the terminal can determine the access point 9 as the connection target access point, and the time information of the next beacon included in the probe response frame 9 The transmission time point of the next beacon 9 or the next auxiliary beacon 9 can be obtained. Here, when the transmission time of the beacon 6 and the transmission time of the beacon 9 temporally overlap, the terminal can determine to receive the auxiliary beacon at the transmission time of the auxiliary beacon 9 having a lower priority than the beacon 9.

If there is not enough time remaining (i.e., time for searching for an access point in another channel) until the transmission time of the next beacon 1, the terminal moves to channel 1 and can receive beacon 1 at the transmission time of beacon 1, After that, the terminal moves to the channel 2 and can receive the beacon 6 at the transmission time of the beacon 6, and then the terminal moves to the channel 3 and can receive the auxiliary beacon 9 at the transmission time of the auxiliary beacon 9.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined in the appended claims. It will be possible.

10: Terminal (STA)
20: access point (AP)

Claims (14)

1. An active search method performed in a terminal,
Transmitting a probe request frame to an access point; And
Receiving a short probe response frame in response to the probe request frame from the access point instead of an existing probe response frame,
Wherein the short probe response frame includes information on a next beacon transmission time,
Wherein the short probe response frame has a shorter length than the conventional probe response frame. The method according to claim 1,
Further comprising receiving a beacon from the access point at a time determined by information on the next beacon transmission time point. The method according to claim 1,
Wherein the terminal operates in a power saving mode for a period of time from the reception of the short probe response frame until a time determined by information on the next beacon transmission time point. The method according to claim 1,
Wherein the terminal performs a search for an access point in another channel for a time from receiving the short probe response frame to a time point determined by information on the next beacon transmission time point. The method according to claim 1,
Wherein the terminal acquires additional information on the access point through a beacon transmitted from the access point at a time determined by information on the next beacon transmission time point. The method according to claim 1,
Wherein the short probe response frame further includes information on an SSID (Service Set ID) of the access point. The method according to claim 1,
The information on the next beacon transmission time point includes information on a time point at which the beacon is transmitted from the access point or information on a time point at which the next auxiliary beacon is transmitted,
Wherein the auxiliary beacon has a shorter transmission period than the beacon and includes less information than the beacon. A method for an active search response of an access point,
Receiving a probe request frame from a terminal;
Transmitting a short probe response frame to the terminal in response to the probe request frame instead of an existing probe response frame,
Wherein the short probe response frame includes information on a next beacon transmission time,
Wherein the short probe response frame has a shorter length than the conventional probe response frame. The method of claim 8,
And transmitting the beacon at a time determined by information on the next beacon transmission time point. The method of claim 8,
The information on the next beacon transmission time includes information on a time point at which the beacon is transmitted from the access point or a time point at which the auxiliary beacon is transmitted,
Wherein the auxiliary beacon has a shorter transmission period than the beacon and includes less information than the beacon. In a terminal performing active search,
Transceiver; And
A processor,
The processor comprising:
Transmitting a probe request frame to an access point using the transceiver;
A short probe response frame responding to the probe request frame from the access point instead of an existing probe response frame using the transceiver,
Wherein the short probe response frame includes information on a next beacon transmission time,
Wherein the short probe response frame has a shorter length than the existing probe response frame. For an access point performing an active search response,
Transceiver; And
A processor,
The processor comprising:
Receiving a probe request frame from the terminal using the transceiver;
A short probe response frame responding to the probe request frame is transmitted to the terminal using the transceiver instead of an existing probe response frame,
Wherein the short probe response frame includes information on a next beacon transmission time,
Wherein the short probe response frame has a shorter length than the existing probe response frame. delete delete

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