KR20140059733A

KR20140059733A - Method for transmitting frame in wireless local area network system

Info

Publication number: KR20140059733A
Application number: KR1020130133780A
Authority: KR
Inventors: 최성현; 최문환; 손위평; 이정수; 정양석; 주원용; 김현표
Original assignee: 주식회사 케이티; 서울대학교산학협력단
Priority date: 2012-11-05
Filing date: 2013-11-05
Publication date: 2014-05-16

Abstract

A method for transmitting a frame in a wireless local area network system is disclosed. The method for transmitting a frame comprises the steps of transmitting an authentication request frame to an access point; receiving an ACK frame indicating that the authentication request frame was successfully received, from the access point; receiving an authentication response frame which is a response to the authentication request frame from the access point; transmitting an ACK frame indicating that the authentication response frame was successfully received, to the access point; and transmitting an association request frame to the access point after a short inter-frame space since transmission of the ACK frame indicating the authentication response frame was successfully received has been completed. Therefore, a terminal can quickly access the access point.

Description

METHOD FOR TRANSMITTING FRAME IN WIRELESS LOCAL AREA NETWORK SYSTEM FIELD OF THE INVENTION [0001]

The present invention relates to a frame transmission method, and more particularly, to a frame transmission method for quickly transmitting a frame 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 a transmission rate of 300 Mbps for two 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 5 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, a terminal can generally perform a three-step access procedure to access (i.e., access) an access point. The first step is a scanning step in which the terminal searches for neighboring access points. In the search phase, the terminal may use a beacon frame or a probe frame to locate neighboring access points. Here, the passive search means a method in which a terminal searches for a corresponding access point using a beacon frame periodically transmitted by an access point, and an active search means that a terminal transmits a probe request frame for each channel It means the way to find the point.

The terminal that has completed the first step can select the most suitable access point among the searched access points and can perform the second step of authentication based on the selected access point. A frame to be exchanged in the second step is called an authentication frame. For convenience, a frame with an authentication transaction sequence number of 1 in the authentication frame means an authentication request frame, and a frame with an authentication processing sequence number of 2 means an authentication response frame Frame. The terminal having completed the second step can perform an association step for connection with the access point.

The wireless LAN access procedure described above requires a handshake between the terminal and the access point in each step. For example, a probe request frame and a probe response frame necessary for the active search, an authentication request frame and an authentication response frame necessary for the authentication process, and a connection request frame and a connection response frame necessary for the connection process, A three-stage handshake consisting of six frames must be successfully performed to access the access point.

In the wireless LAN environment, frame transmission / reception schemes can be classified into a broadcast scheme and a unicast scheme. The broadcast scheme is a scheme for allowing all the neighboring terminals to receive a frame by setting a destination address of the frame to a broadcast medium access control (MAC) address. The unicast method refers to a method in which only a specific terminal can receive a frame by setting a destination address of a frame to a MAC address of a specific terminal.

A terminal (or an access point) that has successfully received a frame in the unicast transmission scheme can transmit an ACK (acknowledgment) frame to an access point (or a terminal) that has transmitted the frame, thereby notifying that the frame has been successfully received have. On the other hand, the terminal (or the access point) that successfully received the frame in the broadcast transmission scheme can omit transmission of the ACK frame.

In the searching step, since the UE often does not know the existence of neighboring access points, it can transmit the probe request frame mainly in a broadcast mode. On the other hand, in the authentication step and the connection step, the UE knows the existence of a specific access point to which the UE desires to connect, and thus can transmit an authentication request frame and a connection request frame mainly to a specific access point in a unicast manner. Meanwhile, in each step, the access point can transmit a response frame to the corresponding terminal in a mostly unicast manner in response to the request frame received from the terminal.

According to such a connection method, a channel connection delay occurs every time a frame is transmitted, and there is a problem that radio resources can not be efficiently used. In addition, the transmission of the ACK frame informing that the frame has been successfully received in the unicast method has a problem of further reducing the efficiency of radio resource use.

SUMMARY OF THE INVENTION An object of the present invention is to provide a frame transmission method for quickly transmitting a frame exchanged between a terminal and an access point.

According to another aspect of the present invention, there is provided a frame transmission method performed in a terminal, the method including transmitting an authentication request frame to an access point, receiving an ACK frame indicating success of reception of the authentication request frame from the access point, Receiving an authentication response frame, which is a response to the authentication request frame, from the access point; transmitting an ACK frame indicating success in receiving the authentication response frame to the access point; And transmitting a connection request frame to the access point after a short inter-frame interval from a point at which transmission of the ACK frame indicating success is completed.

Here, the authentication request frame may include transmission scheme information indicating a frame transmission scheme between the UE and the access point.

Here, the transmission scheme information may indicate that a frame transmitted between the terminal and the access point is transmitted at a short inter-frame interval.

Here, the terminal may receive the authentication response frame from the access point after a short inter-frame interval from the completion of reception of the ACK frame indicating successful reception of the authentication request frame.

Here, the frame transmission method may further include receiving an ACK frame indicating a successful reception of a connection request frame from the access point, and receiving a connection response frame, which is a response to the connection request frame, from the access point .

Here, the terminal may receive the connection response frame from the access point after a short inter-frame interval from the completion of reception of the ACK frame indicating successful reception of the connection request frame.

According to another aspect of the present invention, there is provided a frame transmission method performed in an access point, the method comprising: receiving an authentication request frame from a terminal; transmitting an ACK frame indicating successful reception of the authentication request frame to the terminal; Transmitting an ACK frame indicating the success of reception of the authentication response frame from the terminal to the terminal, receiving an ACK frame indicating the success of the authentication response frame, And receiving a connection request frame from the terminal after a short inter-frame interval from when the reception of the ACK frame is completed.

Here, the access point may transmit the authentication response frame to the terminal after a short inter-frame interval from the completion of transmission of the ACK frame indicating successful reception of the authentication request frame.

Here, the frame transmission method may further include transmitting an ACK frame indicating a successful reception of the connection request frame to the terminal, and transmitting a connection response frame, which is a response to the connection request frame, to the terminal have.

Here, the access point may transmit the connection response frame to the terminal after a short inter-frame interval from the completion of transmission of the ACK frame indicating successful reception of the connection request frame.

According to still another aspect of the present invention, there is provided a frame transmission method performed in a terminal, the method comprising: transmitting an authentication request frame to an access point; receiving, in response to the authentication request frame, Receiving an authentication response frame indicating success from the access point; transmitting a connection request frame indicating successful reception of the authentication response frame to the access point; and transmitting, in response to the connection request frame, Receiving a connection response frame from the access point indicating a successful reception of the access response frame.

Here, the transmission scheme information may indicate that a frame to be transmitted after the ACK frame is transmitted instead of an ACK frame indicating success in receiving a frame when frame reception is successful.

Here, the terminal may receive the authentication response frame from the access point after a short inter-frame interval from the completion of transmission of the authentication request frame.

Here, the terminal may transmit the connection request frame to the access point after a short inter-frame interval from the completion of reception of the authentication response frame.

Here, the terminal may receive the connection response frame from the access point after a short inter-frame interval from the completion of transmission of the connection request frame.

According to the present invention, a channel access delay time caused by frame transmission can be reduced to a short inter-frame space (SIFS), thereby reducing the time required for the terminal to access the access point.

In addition, the terminal (or access point) may transmit a frame to be transmitted next in place of the ACK frame in response to frame reception when the frame is received. According to this method, the radio resources used for transmission of the ACK frame can be reduced, and the time required for the terminal to access the access point can be reduced.

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 process of a terminal accessing an access point.
3 is a flowchart illustrating a frame transmission method according to an embodiment of the present invention.
4 is a conceptual diagram showing an embodiment of a frame transmission method (SIFS exchange) according to the present invention.
5 is a conceptual diagram showing another embodiment of a frame transmission method (SIFS exchange) according to the present invention.
6 is a conceptual diagram showing another embodiment of a frame transmission method (SIFS exchange) according to the present invention.
7 is a flowchart illustrating a frame transmission method according to another embodiment of the present invention.
8 is a conceptual diagram showing the configuration of fast association indication information.
9 is a conceptual diagram showing an embodiment of a frame transmission method (ACK omitted and SIFS exchange) according to the present invention.
10 is a conceptual diagram showing another embodiment of a frame transmission method (ACK omission and SIFS exchange) according to the present invention.
11 is a conceptual diagram showing another embodiment of a frame transmission method (ACK omission and SIFS exchange) according to 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 distribution 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 frame transmission method according to an embodiment of the present invention to be described later 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 (WBAN) And the like.

2 is a conceptual diagram illustrating a process of a terminal accessing an access point.

Referring to FIG. 2, the STA may perform a scanning process, an authentication process, and an association process to access an access point (AP).

In the search process, the STA may transmit a probe request frame for each channel. The access point (AP) receiving the probe request frame can transmit a probe response frame to the terminal (STA) in response to the probe request frame. Through this, the access point (AP) And can inform the terminal (STA).

In the authentication process, the STA may transmit an authentication request frame to an access point (AP) to which the STA searched access points APs. The access point (AP) can perform the authentication procedure for the terminal (STA) based on the information included in the received authentication request frame. If authentication is successfully performed, the access point (AP) may transmit an authentication response frame to the terminal (STA).

In the connection process, the terminal (STA) that has completed the authentication can transmit an association request frame to the access point (AP). The access point (AP) receiving the connection request frame can transmit an association response frame to the terminal (STA) in response to the connection request frame. Through this process, the terminal STA can access the access point (AP) and receive the desired service from the access point (AP).

Here, since the probe request frame is transmitted in a broadcast manner, an ACK (acknowledgment) frame indicating that the probe request frame has been successfully received is not generated. Since the frames other than the probe request frame (for example, the probe response frame, the authentication request frame, the authentication response frame, the connection request frame, and the connection response frame) are transmitted in a unicast manner, An ACK frame may be generated.

Meanwhile, the channel access delay time may vary according to traffice characteristics of a STA attempting to access a channel, and an inter-frame space (IFS) And a randomly selected backoff time.

A short inter-frame space (SIFS) may mean the minimum interval between consecutively transmitted frames. In general, a terminal (or an access point) can transmit an ACK frame after SIFS from the point of time when a frame is completely received. Accordingly, the UE can acquire radio resources necessary for transmission of an ACK frame without competition with other UEs. That is, compared to the fixed IFS for acquiring radio resources and the other UEs waiting for the backoff time, the UE transmitting the ACK frame can wait for SIFS and can access the wireless channel without competition with other UEs.

In general, a UE may perform a countdown in a time slot unit by a backoff time selected randomly when the channel status is idle. If the channel is busy due to other terminals in the vicinity, the terminal may wait until the channel becomes idle and then perform a countdown on the backoff time. Therefore, when there are a large number of terminals or access points sharing the same radio resources in the vicinity, channel competition becomes severe and channel access delay time increases.

3 is a flowchart illustrating a frame transmission method according to an embodiment of the present invention.

Referring to FIG. 3, the terminal 10 may perform an authentication process and a connection process with the discovered access point 20 after the search process is completed. Here, the search process may refer to an active search process using a probe request frame and a probe response frame or a manual search process using a beacon frame.

The terminal 10 can transmit an authentication request frame to the access point 20 (S100). The authentication request frame may include transmission scheme information indicating a frame transmission scheme between the terminal 10 and the access point 20. [ The transmission scheme information may indicate that frames transmitted continuously between the terminal 10 and the access point 20 are transmitted at a short inter-frame interval.

That is, the transmission scheme information includes an interval between the ACK frame and the authentication response frame for the authentication request frame, an interval between the ACK frame and the connection request frame for the authentication response frame, and an interval between the ACK frame and the connection response frame for the connection request frame - It can indicate the frame interval.

Here, the transmission scheme information is included in the authentication request frame, but the frame including the transmission scheme information is not limited thereto. That is, the transmission scheme information is included in a probe request frame, a probe response frame, a beacon frame, an authentication response frame, a connection request frame, a connection response frame, a reassociation request frame, a reassociation response frame, . Alternatively, the transmission scheme information may be included in a separate frame (for example, a control frame, a data frame, or the like).

If the authentication request frame is successfully received, the access point 20 may transmit an ACK frame indicating successful reception of the authentication request frame to the terminal 10 (S110). Thereafter, the access point 20 may transmit an authentication response frame, which is a response to the authentication request frame, to the terminal 10 after SIFS from the completion of transmission of the ACK frame (S120).

However, if the access point 20 fails to complete the preparation for transmitting the authentication response frame for the SIFS time from the completion of transmission of the ACK frame, the access point 20 proceeds to the radio channel access competition process (i.e., To the terminal 10, the authentication response frame.

If the authentication response frame is successfully received, the terminal 10 may transmit an ACK frame indicating the success of the authentication response frame to the access point 20 (S130). Thereafter, the terminal 10 may transmit a connection request frame to the access point 20 after SIFS from the completion of transmission of the ACK frame (S140).

However, if the terminal 10 fails to complete preparation for transmitting a connection request frame for a time equal to SIFS from the time of completing the transmission of the ACK frame, the terminal 10 transmits a connection request frame to the access point 20 ).

When the connection request frame is successfully received, the access point 20 may transmit an ACK frame indicating the success of the connection request frame to the terminal 10 (S150). Thereafter, the access point 20 may transmit a connection response frame, which is a response to the connection request frame, to the terminal 10 after SIFS from the completion of transmission of the ACK frame (S160).

However, if the access point 20 can not complete the preparation for transmitting the connection response frame for a time equal to SIFS from the time of completing transmission of the ACK frame, the access point 20 transmits a connection response frame to the terminal 10 ).

If the connection response frame is successfully received, the terminal 10 may transmit the ACK frame indicating the success of the connection response frame to the access point 20 (S170).

4 is a conceptual diagram showing an embodiment of a frame transmission method (SIFS exchange) according to the present invention.

Referring to FIG. 4, after completing the searching process, the STA may perform an authentication process and a connection process with the most suitable AP among the discovered APs.

The terminal (STA) can transmit an authentication request frame to an access point (AP) through a wireless channel access competition. The authentication request frame may include transmission scheme information indicating a transmission scheme between the STA and the AP. The transmission scheme information may indicate that the interval between consecutive frames transmitted between the STA and the AP is SIFS.

When the authentication request frame is successfully received, the access point (AP) can transmit an ACK frame to the terminal (STA). Thereafter, the access point (AP) can transmit the authentication response frame to the terminal (STA) after SIFS from the point of time when the transmission of the ACK frame is completed according to the transmission method of the frame.

If the authentication response frame is successfully received, the terminal (STA) can transmit an ACK frame to the access point (AP). Thereafter, the terminal STA may transmit the connection request frame to the access point (AP) after SIFS from the point of time when the transmission of the ACK frame is completed according to the transmission method of the frame.

When the connection request frame is successfully received, the access point (AP) can transmit an ACK frame to the terminal (STA). Thereafter, the access point (AP) may transmit a connection response frame to the terminal (STA) after SIFS from the point of time when the transmission of the ACK frame is completed according to the transmission method of the frame.

If the connection acknowledgment frame is successfully received, the terminal (STA) can transmit an ACK frame to the access point (AP).

On the other hand, if the terminal or the access point can not complete preparation for transmission of the next frame, it may be difficult to transmit the frame at short inter-frame intervals. This situation may occur when it is difficult for the terminal or the access point to predict a frame to be transmitted next. For example, the terminal that has completed the search process can select the most suitable access point among the discovered access points and transmit the authentication request frame to the selected access point.

On the other hand, the access point may not know whether to select itself until it receives an authentication request frame from the terminal. Therefore, the access point may not be able to complete the preparation for transmission of the authentication response frame for a time equal to SIFS from the time of completing the transmission of the ACK frame for the authentication request frame.

In this case, even when the access point indicates that the interval between successive frames of the transmission scheme information included in the authentication request frame is SIFS, the access point can transmit the authentication response frame after completing the wireless access competition procedure.

5 is a conceptual diagram showing another embodiment of a frame transmission method (SIFS exchange) according to the present invention.

Referring to FIG. 5, after completing the searching process, the STA can perform an authentication process and a connection process with the most suitable AP among the discovered APs.

When the authentication request frame is successfully received, the access point (AP) can transmit an ACK frame to the terminal (STA). ACK frame, the access point (AP) can transmit the authentication response frame to the terminal (STA) after completing the wireless channel access competition have.

On the other hand, the access point may not be able to complete the preparation of transmission of the connection response frame for a time equal to SIFS from the time of completion of transmission of the previous frame. That is, after receiving the connection request frame, the access point generates a connection response frame including the authentication information or the IP address, a procedure of acquiring the authentication information with the remote authentication dial-in-user services (RADIUS) protocol (IP) address assignment procedure with the server. In performing such a procedure, it is difficult for the access point to transmit the connection response frame for SIFS time from the completion of transmission of the ACK frame, so that the access point can transmit the connection response frame after the wireless channel access competition.

6 is a conceptual diagram showing another embodiment of a frame transmission method (SIFS exchange) according to the present invention.

Referring to FIG. 6, after completing the searching process, the STA can perform an authentication process and a connection process with the most suitable AP among the discovered APs.

When the connection request frame is successfully received, the access point (AP) can transmit an ACK frame to the terminal (STA). The access point (AP) can transmit the connection response frame to the terminal (STA) after completing the wireless channel access competition if it can not complete the preparation of transmission of the connection response frame for SIFS time from the completion of transmission of the ACK frame have.

On the other hand, if the terminal (or the access point) can predict a frame to be transmitted / received next time, transmission of an ACK frame may be omitted and the next frame may be transmitted. That is, if the UE successfully receives a frame transmitted from the access point, it can transmit a frame to be transmitted next to the access point instead of the ACK frame. The access point that received the next frame to be received instead of the ACK frame can confirm that the previously transmitted frame has been successfully received by the terminal.

7 is a flowchart illustrating a frame transmission method according to another embodiment of the present invention.

Referring to FIG. 7, the terminal 10 can perform an authentication process and a connection process with the discovered access point 20 after the search process is completed. Here, the search process may refer to an active search process using a probe request frame and a probe response frame or a manual search process using a beacon frame.

The terminal 10 may transmit an authentication request frame to the access point 20 (S200). The authentication request frame may include transmission scheme information indicating a frame transmission scheme between the terminal 10 and the access point 20. [

The transmission scheme information may indicate that the transmission of the ACK frame indicating success of reception of the frame is omitted. That is, the transmission scheme information is generated by omitting the transmission of the ACK frame indicating the successful reception of the authentication request frame, sending the authentication response frame of the next frame, omitting the transmission of the ACK frame indicating the successful reception of the authentication response frame, Transmission, and transmission of the ACK frame indicating successful reception of the connection request frame, and to perform the connection response frame transmission, which is the next frame.

In addition, the transmission scheme information may indicate that the interval between consecutive frames transmitted between the terminal 10 and the access point 20 is SIFS. That is, the transmission scheme information may indicate that the interval between the authentication request frame and the authentication response frame, the interval between the authentication response frame and the connection request frame, and the interval between the connection request frame and the connection response frame are SIFS.

8 is a conceptual diagram showing the configuration of fast association indication information.

Referring to FIG. 8, the fast connection indication information may have a size of 3 octets, and may include an element ID field, a length field, and a transmission scheme field. The element ID field may indicate that the information is quick connect indication information. The length field may indicate the length of the transmission scheme field.

The transmission scheme field indicates the transmission scheme information described above, and may include a SIFS exchange field, an ACK omitted field, and a reserved field. The SIFS exchange field may indicate that the interval between consecutive frames transmitted between the terminal and the access point is SIFS. For example, if the interval of consecutive frames transmitted between the terminal and the access point is SIFS, the value of the SIFS exchange field is set to 1; otherwise, it is set to zero.

The ACK omitted field may indicate that transmission of an ACK frame indicating success of reception of a frame is omitted. For example, if transmission of an ACK frame indicating successful reception of a frame is omitted, the value of the ACK skip field is set to 1; otherwise, it is set to zero.

Here, the quick connection indication information may be included in a probe request frame, a probe response frame, a beacon frame, an authentication request frame, an authentication response frame, a connection request frame, a connection response frame, a reconnection request frame, Alternatively, the quick connect indication information may be included in a separate frame (e.g., control frame, data frame, etc.).

Referring again to FIG. 7, when the authentication request frame is successfully received, the access point 20 may skip the transmission of the ACK frame indicating the successful reception of the authentication request frame. Thereafter, the access point 20 may transmit an authentication response frame to the terminal 10 in response to the authentication request frame (S210).

At this time, the access point 20 can transmit the authentication response frame to the terminal 10 after SIFS from the time when the reception of the authentication request frame is completed. If the access point 20 fails to complete the preparation for transmitting the authentication response frame for SIFS time from the completion of the reception of the authentication request frame, the access point 20 transmits an authentication response frame to the terminal 10).

When the authentication response frame is successfully received, the terminal 10 can determine that the access point 20 has successfully received the authentication request frame. The terminal 10 may skip the transmission of the ACK frame indicating the successful reception of the authentication response frame. Thereafter, the terminal 10 can transmit a connection request frame to the access point 20 (S220).

At this time, the terminal 10 can transmit a connection request frame to the access point 20 after SIFS from the time of completing the reception of the authentication response frame. If the terminal 10 can not complete the preparation for transmitting the connection request frame for a time equal to SIFS from the time when the reception of the authentication response frame is completed, the terminal 10 transmits a connection request frame to the access point 20).

On the other hand, if the authentication response frame is not received within a predetermined time, the terminal 10 can determine that the access point 20 has not successfully received the authentication request frame. In this case, the terminal 10 can retransmit the authentication request frame to the access point 20. Here, the predefined time may mean a time longer than the ACK time out.

When the connection request frame is successfully received, the access point 20 can determine that the terminal 10 has successfully received the authentication response frame. The access point 20 may omit the transmission of the ACK frame indicating the successful reception of the connection request frame. Thereafter, the access point 20 may transmit a connection response frame to the terminal 10 in response to the connection request frame (S230).

At this time, the access point 20 can transmit the connection response frame to the terminal 10 after SIFS from the point of time when the reception of the connection request frame is completed. If the access point 20 fails to complete the preparation for transmitting the connection response frame for the SIFS time from the completion of the reception of the connection request frame, the access point 20 transmits a connection response frame to the terminal 10).

On the other hand, if the connection request frame is not received within a predefined time, the access point 20 can determine that the terminal 10 has not successfully received the authentication response frame. In this case, the access point 20 can retransmit the authentication response frame to the terminal 10. Here, the predefined time may mean a time longer than the ACK timeout.

If the connection response frame is successfully received, the terminal 10 may transmit an ACK frame for success of the connection response frame to the access point 20 (S240).

On the other hand, if the connection response frame is not received within the predetermined time, the terminal 10 can determine that the access point 20 has not successfully received the connection request frame. In this case, the terminal 10 can retransmit the connection request frame to the access point 20. Here, the predefined time may mean a time longer than the ACK timeout.

9 is a conceptual diagram showing an embodiment of a frame transmission method (ACK omitted and SIFS exchange) according to the present invention.

Referring to FIG. 9, after completing the searching process, the STA can perform an authentication process and a connection process with the most suitable AP among the discovered APs.

The terminal (STA) can transmit an authentication request frame to an access point (AP) through a wireless channel access competition. The authentication request frame may include transmission scheme information indicating a transmission scheme between the STA and the AP. The transmission scheme information may indicate that the transmission of the ACK frame indicating success of reception of the frame is omitted.

If the authentication request frame is successfully received, the access point (AP) can transmit an authentication response frame to the terminal (STA) in response to the authentication request frame. At this time, the access point (AP) can transmit the authentication response frame to the terminal (STA) after completing the wireless channel access competition procedure.

When the authentication response frame is successfully received, the terminal (STA) can determine that the access point (AP) has successfully received the authentication request frame. Thereafter, the terminal STA may transmit a connection request frame to the access point (AP). At this time, the STA may transmit a connection request frame to an access point (AP) after completing a radio channel access competition procedure.

If the connection request frame is successfully received, the access point (AP) can determine that the terminal (STA) has successfully received the authentication response frame. Thereafter, the access point (AP) can transmit a connection response frame to the terminal (STA) in response to the connection request frame. At this time, the access point (AP) can transmit the connection response frame to the terminal (STA) after completing the wireless channel access competition procedure.

If the connection response frame is successfully received, the terminal (STA) can transmit an ACK frame to the access point (AP) for the successful reception of the connection response frame.

10 is a conceptual diagram showing another embodiment of a frame transmission method (ACK omission and SIFS exchange) according to the present invention.

Referring to FIG. 10, after completing the searching process, the STA may perform an authentication process and a connection process with the most suitable AP among the discovered APs.

The terminal (STA) can transmit an authentication request frame to an access point (AP) through a wireless channel access competition. The authentication request frame may include transmission scheme information indicating a transmission scheme between the STA and the AP. The transmission scheme information may indicate that the transmission of the ACK frame indicating success of reception of the frame is omitted. In addition, the transmission scheme information may indicate that the interval between consecutive frames transmitted between the STA and the AP is SIFS.

If the authentication request frame is successfully received, the access point (AP) can transmit an authentication response frame to the terminal (STA) in response to the authentication request frame. At this time, the access point (AP) can transmit the authentication response frame to the terminal (STA) after SIFS from the completion of the reception of the authentication request frame.

When the authentication response frame is successfully received, the terminal (STA) can determine that the access point (AP) has successfully received the authentication request frame. Thereafter, the terminal STA may transmit a connection request frame to the access point (AP). At this time, the STA can transmit a connection request frame to the access point (AP) after SIFS from the time when the STA completes the reception of the authentication response frame.

If the connection request frame is successfully received, the access point (AP) can determine that the terminal (STA) has successfully received the authentication response frame. Thereafter, the access point (AP) can transmit a connection response frame to the terminal (STA) in response to the connection request frame. At this time, the access point (AP) can transmit the connection response frame to the terminal (STA) after SIFS from the point of time when the connection request frame is completely received.

Meanwhile, the terminal and the access point can adaptively apply the above-described transmission scheme (ACK frame omitted, frame interval set to SIFS).

11 is a conceptual diagram showing another embodiment of a frame transmission method (ACK omission and SIFS exchange) according to the present invention.

Referring to FIG. 11, after completing the searching process, the STA can perform an authentication process and a connection process with the most suitable AP among the discovered APs.

If the authentication request frame is successfully received, the access point (AP) can transmit an authentication response frame to the terminal (STA) in response to the authentication request frame. In this case, if the preparation for transmitting the authentication response frame for SIFS is not completed from the time when the reception of the authentication request frame is completed, the access point (AP) transmits the authentication response frame to the terminal STA).

If the connection request frame is successfully received, the access point (AP) can determine that the terminal (STA) has successfully received the authentication response frame. Thereafter, the access point (AP) can transmit a connection response frame to the terminal (STA) in response to the connection request frame. In this case, if the preparation for transmitting the connection response frame for SIFS is not completed from the time of completion of reception of the connection request frame, the access point (AP) transmits a connection response frame to the terminal STA).

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
20: access point

Claims

A frame transmission method performed in a terminal,
Transmitting an authentication request frame to an access point;
Receiving an ACK (acknowledgment) frame indicating success of reception of the authentication request frame from the access point;
Receiving an authentication response frame, which is a response to the authentication request frame, from the access point;
Transmitting an ACK frame indicating success in receiving the authentication response frame to the access point; And
Transmitting an association request frame to the access point after a short inter-frame space (SIFS) from a point at which transmission of the ACK frame indicating successful reception of the authentication response frame is completed Containing frame transmission method.

The method according to claim 1,
The authentication request frame includes:
And transmission scheme information indicating a frame transmission scheme between the terminal and the access point.

The method of claim 2,
The transmission method information includes:
Wherein a frame transmitted between the terminal and the access point is transmitted in a short inter-frame interval.

The method according to claim 1,
The terminal,
Wherein the authentication response frame is received from the access point after a short inter-frame interval from the completion of reception of the ACK frame indicating the successful reception of the authentication request frame.

The method according to claim 1,
The frame transmission method includes:
Receiving an ACK frame indicating success in receiving a connection request frame from the access point; And
Further comprising receiving a connection response frame from the access point in response to the connection request frame.

The method of claim 5,
The terminal,
Wherein the connection acknowledgment frame is received from the access point after a short inter-frame interval from a point of time when reception of the ACK frame indicating successful reception of the connection request frame is completed.

A frame transmission method performed at an access point,
The method comprising: receiving an authentication request frame from a terminal;
Transmitting an ACK (acknowledgment) frame indicating success in receiving the authentication request frame to the terminal;
Transmitting an authentication response frame, which is a response to the authentication request frame, to the terminal;
Receiving an ACK frame indicating success in receiving the authentication response frame from the terminal; And
Receiving an association request frame from the terminal after a short inter-frame space (SIFS) from a point of time when the reception of the ACK frame indicating successful reception of the authentication response frame is completed Frame transmission method.

The method of claim 7,
The authentication request frame includes:
And transmission scheme information indicating a frame transmission scheme between the terminal and the access point.

The method of claim 8,
The transmission method information includes:
Wherein a frame transmitted between the terminal and the access point is transmitted in a short inter-frame interval.

The method of claim 7,
The access point comprising:
Wherein the authentication response frame is transmitted to the terminal after a short inter-frame interval from a point at which transmission of the ACK frame indicating successful reception of the authentication request frame is completed.

The method of claim 7,
The frame transmission method includes:
Transmitting an ACK frame indicating successful reception of the connection request frame to the terminal; And
And transmitting a connection response frame, which is a response to the connection request frame, to the terminal.

The method of claim 11,
The access point comprising:
Wherein the connection response frame is transmitted to the terminal after a short inter-frame interval from a point of time when transmission of an ACK frame indicating successful reception of the connection request frame is completed.

A frame transmission method performed in a terminal,
Transmitting an authentication request frame to an access point;
Receiving, in response to the authentication request frame, an authentication response frame indicating success of the authentication request frame from the access point;
Transmitting an association request frame to the access point indicating a successful reception of the authentication response frame; And
And receiving, from the access point, a connection response frame indicating a successful reception of the connection request frame, in response to the connection request frame.

14. The method of claim 13,
The authentication request frame includes:
And transmission scheme information indicating a frame transmission scheme between the terminal and the access point.

15. The method of claim 14,
The transmission method information includes:
Wherein a frame transmitted between the terminal and the access point is transmitted in a short inter-frame space (SIFS).

15. The method of claim 14,
The transmission method information includes:
When the frame is successfully received, indicating to transmit a frame to be transmitted after the ACK frame instead of an ACK (acknowledgment) frame indicating that the frame is successfully received.

14. The method of claim 13,
The terminal,
Wherein the authentication response frame is received from the access point after a short inter-frame interval from the completion of transmission of the authentication request frame.

14. The method of claim 13,
The terminal,
And the connection request frame is transmitted to the access point after a short inter-frame interval from the completion of reception of the authentication response frame.

14. The method of claim 13,
The terminal,
Wherein the connection acknowledgment frame is received from the access point after a short inter-frame interval from a point at which transmission of the connection request frame is completed.