KR20090098423A - Tunneled direct link setup in wireless local access network - Google Patents

Abstract

A tunneled direct link setup in a wireless local access network is provided to set up a direct link efficiently by enabling a station to be operated in a power-saving mode after setting up a direct link. An initiation station transmits a TDLS setup request frame, which requests for the setting up a direct link, to a peer STA via an AP(S11). The peer STA that receive the request frame for setting up TDLS transmits a TDSL setup response frame to the initiation STA via the AP(S12). The initiation STA transmits the TDSL setup confirmation frame for the received TDSL setup response frame to the peer STA via the AP(S13).

Description

Tunneled Direct Link Setup in Wireless Local Access Network

The present invention relates to a Wireless Local Access Network (WLAN), and more particularly, to a Tunneled Direct Link Setup (TDLS) procedure and a device supporting the same, and a new TDLS for the procedure. Frame format.

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

Early WLAN technology used 2.4 GHz frequency through IEEE 802.11 to support 1 ~ 2Mbps speed by frequency hopping, spread spectrum, infrared communication. Recently, with the development of wireless communication technology, orthogonal frequency division multiplex (OFDM) technology is applied to a wireless LAN to support a speed of up to 54 Mbps. In addition, IEEE 802.11 improves the quality of service (QoS), access point (AP) protocol compatibility, security enhancement, radio resource measurement, and wireless access for vehicle environments. Wireless communication technologies for Wireless Access in Vehicular Environment, Fast Roaming, Mesh Network, Inter-working with External Network, Wireless Network Management, etc. Has been developed for practical use or is still under development.

In IEEE 802.11, a basic service set (BSS) refers to a set of STAs that are successfully synchronized. The Basic Service Area (BSA) refers to the area that contains the members constituting the BSS. The boundary is somewhat unclear because the BSA may vary depending on the propagation characteristics of the wireless medium. BSS can be classified into two basic types: Independent BSS (IBSS) and Infrastructure BSS (Infrastructured BSS). The former forms a self-contained network as a distributed system. (BSS) means that BSS is not allowed to connect to (Distribution System, DS), and the latter includes one or more Access Points (APs) and distributed systems, and generally all communication processes including communication between stations. Refers to the BSS used by the AP.

According to the initial WLAN communication procedure, the infrastructure BSS does not allow direct transmission of data between non-AP STAs, but requires that the data be transmitted via the AP for data transmission. On the other hand, in recent years, direct link setup (DLS) between non-AP STAs is supported to improve wireless communication efficiency. According to this, in the BSS supporting Quality of Service (QoS), that is, the Quality of Service Basic Service Set (QBSS) including Quality of Service Station (QSTA) and Quality of Service Access Point (QAP), the non-AP station (Non- AP STAs may establish a direct link and communicate directly via the direct link without passing through QAP.

As described above, the existing DLS configuration procedure assumes QBSS that QoS is supported by the BSS. In QBSS, not only non-AP STAs but also APs are QAPs that support QoS. However, in the currently commercialized wireless LAN environment (eg, wireless LAN environment according to IEEE 802.11a / b / g), even if the Non-AP STA is a QSTA supporting QoS, the AP may not support QoS. AP is mostly. As a result, even in the currently commercialized wireless LAN environment, even QSTA, there is a limit that can not use the DLS service.

Tunneled Direct Link Setup (TDLS) is a newly proposed wireless communication protocol to overcome this limitation. Although TDLS does not support QoS, QSTAs can establish a direct link even in a wireless LAN environment such as IEEE 802.11a / b / g, which is currently commercially available. Therefore, TDLS prescribes various procedures for enabling QSTAs to establish a direct link even in a BSS managed by a legacy AP. Hereinafter, a wireless network supporting the TDLS procedure is called a TDLS wireless network.

Meanwhile, the non-AP STA constituting the BSS operates in one of two power management modes, that is, active mode (AM) and power save mode (PSM). . Since the Non-AP STA is generally a portable device belonging to the user, it is essential to support the PSM to efficiently manage power. In this case, it is preferable to allow the STA operating as the PSM to establish a direct link.

However, the existing direct link setup procedure, particularly the TDLS procedure, assumes that the Non-AP STA is in an active mode. As a result, the direct link cannot be set when any STA or the other STA to set the direct link is in the power saving mode, and the STA must change from the power saving mode to the active mode in order to set the direct link. do.

Accordingly, an object of the present invention is to provide a procedure for establishing a TDLS link in which a starting STA or a peer STA can negotiate a transmission path to be used after the TDLS configuration procedure in a WLAN.

Another problem to be solved by the present invention is to provide a TDLS link setup procedure that allows a direct link to be established even when the STA is in a power saving mode in a WLAN.

Another problem to be solved by the present invention is to establish a direct link even when the initiating STA or the peer STA can negotiate a transmission path to be used after the TDLS setup procedure in the WLAN in the WLAN or when the STA is in a power saving mode. It is to provide a device that supports a TDLS link setup procedure that allows it, and a format of a TDLS setup request frame and a TDLS setup response frame that can be used therefor.

TDLS setup procedure performed between the initiation station and the peer station according to an embodiment of the present invention for solving the above problems is that the transmission path that the initiation station and the peer station to use after the end of the TDLS setup procedure is a direct link Determine whether it is a route or an access point route.

According to an aspect of the present embodiment, the transmission path may negotiate using a TDLS setup request frame and / or a TDLS setup response frame including a path element. In this case, when the path element included in at least one of the TDLS establishment request frame and the TDLS establishment response frame indicates an access point path, the transmission path between the initiating station and the peer station is It may necessarily be determined as an access point path.

According to another aspect of this embodiment, the initiating station and / or the peer station may operate in a power saving mode after the end of the TDLS setup procedure.

The TDLS setting procedure according to another embodiment of the present invention for solving the above problems includes a tunnel direct link setup including a first path element having information indicating a direct link path or an access point path. TDLS) setup request frame is transmitted to the peer station, and in response to the TDLS setup request frame, a TDLS setup response frame including a second path element having information indicating a direct link path or an access point path is set. Receiving and transmitting a TDLS setup confirmation request frame in response to the TDLS setup response frame.

The TDLS setup request frame or the TDLS setup response frame according to another embodiment of the present invention for solving the above problems includes a path element for indicating a direct link path or an access point path.

According to an embodiment of the present invention, even when at least one of two STAs for establishing a TDLS link operates in a power saving mode, the STA and the TDLS configuration procedure may be successfully performed. By using a TDLS setup request or a path element of a TDLS setup response for the TDLS setup with the STA, the initiating STA and the peer STA autonomously start a frame transmission path to be used after the TDLS link setup is successfully established. You can decide. Therefore, according to the embodiment of the present invention, even if the STA is in the power saving mode, it is possible to establish a direct link with another STA, and even after the direct link is set, it can be operated in the power saving mode again, so that the efficient direct link is set. Not only can this be possible, but the STA can also efficiently manage power.

Hereinafter, with reference to the accompanying drawings will be described in detail an embodiment of the present invention.

In a TDLS wireless network to which an embodiment of the present invention can be applied, even a non-AP STA that is associated with a legacy AP can establish a TDLS link, which is a direct link, and release the established TDLS link. In order for one STA to establish or release a TDLS link with the other STA, management action frames, for example, TDLS frames, must be able to be transmitted and received through the legacy AP. However, the legacy AP does not have a problem that two non-AP STAs may not be directly involved in establishing a TDLS link.

One way to solve this problem is to encapsulate the TDLS frame in the form of a data frame and transmit it to the counterpart STA via the legacy AP. According to this, the legacy AP only performs a function of relaying communication between the non-AP STAs, and does not participate in the procedure of establishing, managing, or releasing the TDLS link. The embodiments of the present invention described below may be usefully applied to a TDLS wireless network that transmits and receives an encapsulated TDLS frame in the form of a data frame for establishing, releasing, and managing the TDLS link.

Among the devices constituting the TDLS wireless network, the Non-AP STA is any device including a medium access control and a physical layer interface to a wireless medium that conforms to the IEEE 802.11 standard. Non-AP STA is a wireless device (not a AP), each of which is a wireless transmit / receive unit (WTRU), a user equipment (UE), a mobile station (MS), or a terminal (terminal). , Or a Mobile Subscriber Unit.

The non-AP STA includes a processor and a transceiver, and generally may further include a user interface and a display means. The processor is a functional unit designed to generate a frame for transmission over a wireless network or to process a frame received over the wireless network, controlling a station and performing various signal processing functions input by and for the user. The transceiver is a unit that is functionally connected to the processor and is designed to transmit and receive frames over a wireless network for a station.

In addition, the Non-AP STA supports a TDLS configuration procedure in a power saving mode in a TDLS wireless network described later. According to this, in order to establish a TDLS link with a peer STA, the non-AP STA may establish a TDLS link even when the peer STA is in a power saving mode. When the TDLS link is requested from the peer STA, the direct link can be established with the peer STA by accepting the TDLS setup request even when operating in the power saving mode. In addition, after establishing the TDLS link, it is possible to determine whether the transmission path of the frame is the AP path or the direct link path.

The AP is a functional entity that has a radio station function and also provides access to a Distribution System (DS) via a wireless medium for an associated station. According to an embodiment of the present invention, the AP may be a legacy AP that does not support Quality of Service (QoS). Such an AP may be called a central controller, a base station (BS), a node B, or a site controller.

FIG. 1 illustrates a medium access control (MAC) frame (hereinafter, referred to as a 'TDLS frame') in which a first non-AP STA communicates with a counterpart non-AP STA (or peer STA) via a legacy AP in a TDLS wireless network. Block diagram). Referring to FIG. 1, the TDLS frame includes a MAC header field, a MAC, a logical link control (LLC) / sub-network access protocol (SNAP) field, a remote frame type field (Remote Frame). Type), a TDLS Packet Type field (TDLS Packet Type), an information field (Information), and an error correction field (Cyclic Redundancy Code, CRC). The TDLS frame may further include a protocol version field.

The MAC header field contains information common to almost all types of frames. For example, the MAC head field may include a frame control field (Frame Control), a duration / ID field (Duration / ID), a plurality of address fields (Address1, Address2, Address3, Address4), a sequence control field, and And / or a Quality of Service (QoS) control field (QoS Control).

Among these, the frame control field is a protocol version field, a type and subtype field for identifying the function of the frame, and an additional for indicating whether there is an additional fragment of the current MSDU or MMPDU that follows. A program field (More Fragments), a retry field (Retry) for indicating whether the frame is retransmitted, a power management field (Power Management) for indicating whether to operate in the power saving mode. The power management field of the frame control field indicates the mode in which the STA operates after successfully completing a series of frame exchanges. For example, when the power management field is set to '0', it indicates that the transmitting STA of the frame operates in an active mode, but when the power management field is set to '1', the transmitting STA saves peer power. It can be shown that the operation in the mode.

The quality of service control field is for identifying various quality of service related information about a traffic category (TC) or a traffic stream (TS) to which a frame belongs, and a frame that varies depending on the frame type and subtype. . This quality of service control field may exist in all TDLS frames in which the QoS subfield of the subtype field of the frame is set to '1'. Each quality of service control field includes five subfields, examples of the use of these subfields and various possible layouts are shown in Table 1.

With continued reference to FIG. 1, the LLC / SNAP field includes an LLC / SNAP header. And the remote frame type field may be set to a value (eg, '2') indicating that the TDLS frame. The protocol version field may be set to a value for indicating a protocol version of a transmission / reception message.

The TDLS Packet Type field is set to a value for specifying the type of the TDLS frame. An example of a type of TDLS frame and its corresponding value is shown in FIG. 2. Referring to FIG. 2, the TDLS frame includes a TDSL setup request frame, a TDLS setup response frame, a TDLS setup response frame, a TDLS setup confirmation frame, and a TDLS Rx switch request frame. ), And a TDLS Rx Switch Response frame.

The error correction field (CRC) includes additional information for error correction when a part of data is lost or an error occurs during transmission of the corresponding frame.

The information field of the TDLS frame includes various pieces of information that are individually specified according to the type of each TDLS frame. The information included in the information field differs according to each TDLS type. In an embodiment of the present invention, information elements included in an information field of a TDLS configuration request frame and / or a TDLS configuration response frame are newly defined. More specifically, a path element may be included in the TDLS configuration request frame and / or the TDLS configuration response frame. ) Is included.

3 is a block diagram illustrating information included in an information field of a TDLS configuration request frame according to an embodiment of the present invention.

Referring to FIG. 3, the information field of the TDLS setup request frame includes a link identifier, an association request frame body, a dialog token, and a robust secure network information element (RSNIE_I) for the initiating STA. ), STSL (Station To Station Link) master key message 1 FTIE (SMK Message 1 FTIE) and DH (DH_I) for the initiating STA.

The link identifier includes information for identifying the direct link. For example, the link identifier may include a BSSID to which the STA is currently coupled, a MAC address of the source STA, a MAC address of the target STA, a regulatory class to which the STA is currently coupled, and channel information. Combined request frame bodies include Capability, Listen Interval, Service Set ID, Supported Rates, Extended Supported Rates, Power Capability, Support Channel. (Supported Channels), a robust security network (RSN), and / or QoS capabilities. The dialog token also contains a unique value for this conversation.

According to the embodiment of the present invention, the information element of the TDLS setup request frame further includes path information. The path element (Path) is for identifying the path selected for the direct link, and the path information included in the information field of the TDLS establishment request frame includes information about a transmission path to request use after the TDLS establishment procedure is finished. . One example of a format for a path element is shown in FIG.

Referring to FIG. 4, the path element includes an element identifier field (Element ID), a length field (Length), and a path field (Path). The element identifier field is set to a value indicating a path element. The length field may be set to a value indicating the length of the path field, for example, 1. The path field may be set to a value indicating a transmission path that an STA transmitting this intends to use after the TDLS configuration procedure is terminated. For example, when the path field is set to '0', the AP path may be indicated, and when the path field is set to '1', the direct link path may be indicated.

FIG. 5 is a block diagram illustrating information included in an information field of a TDLS configuration response frame according to an embodiment of the present invention.

Referring to FIG. 5, an information field of a TDLS configuration response frame includes a link identifier, a status code, an association request frame body, a dialog token, and a peer STA. A robust secure network information element (RSNIE_P), a station to station link (STSL) master key message 2 FTIE (SMK Message 2 FTIE) and a DH (DH_P) for peer STA.

The link identifier includes information for identifying the direct link. For example, the link identifier may include a BSSID to which the STA is currently coupled, a MAC address of the source STA, a MAC address of the target STA, a regulatory class to which the STA is currently coupled, and channel information. The status code is for indicating the success or failure of the requested operation. For example, the status code is set to '0' when the operation indicates success, and when the operation indicates a failure, indicating a cause of failure. It can be set to a predetermined value.

Combined request frame bodies include Capability, Listen Interval, Service Set ID, Supported Rates, Extended Supported Rates, Power Capability, Support Channel. (Supported Channels), Robust Security Network (RSN), and / or QoS capabilities, such as the association request frame body can be included only if the status code is set to a value indicating 'success'. The dialog token also contains a unique value for this conversation.

In addition, according to an embodiment of the present invention, the information element of the TDLS setup response frame also includes a path element. The path element (Path) is for identifying the path selected for the direct link, and the path information included in the information field of the TDLS establishment request frame includes information about a transmission path to request use after the TDLS establishment procedure is finished. . Since an example of a format for the path element has been described with reference to FIG. 4, a detailed description thereof will be omitted.

As such, according to an embodiment of the present invention, path information is further included in the TDLS setup request frame and / or the TDLS setup response frame. This path information is used to indicate a transmission path that the STA transmitting the frame, for example, the initiating STA or the peer STA, wishes to use after establishing the TDLS link.

In addition, according to an embodiment of the present invention, the initiating STA and / or the peer STA that wants to set up the TDLS link may proceed with the TDLS setup procedure by specifying a transmission path to be used after setting up the TDLS link. That is, the initiating STA or the peer STA may determine whether to use the AP path or the direct link path after setting up the TDLS link. In this case, the initiating STA or the peer STA may wish to operate in the power saving mode (PSM) even after the TDLS link is set up, or may make the transmission path an AP path for reasons such as other channel conditions. Accordingly, according to the embodiment of the present invention, even when either the starting STA or the peer STA operates in the power saving mode, the direct link may be set through the TDLS setting procedure.

Next, a TDLS setting procedure according to an embodiment of the present invention will be described.

FIG. 6 is a message flow diagram illustrating a TDSL configuration procedure in a TDLS wireless network including two Non-AP STAs (hereinafter, simply referred to as STAs and distinguished from a starting STA and a peer STA) and a legacy AP.

Referring to FIG. 6, the initiating STA that wants to establish a direct link with the peer STA transmits a frame for requesting the establishment of the direct link, for example, a TDLS setup request frame, to the peer STA via the AP (S11). The TDLS setup request frame may be a frame in which the TDLS packet type field is set to a value indicating a TDLS setup request in the TDLS frame of FIG. 1. Therefore, in step S11, the TDLS setup request is encapsulated and transmitted in the form of a data frame, and if the received frame is a TDLS setup request frame, the AP performs a function for relaying the peer STA as a receiving STA.

Since the format of the TDLS configuration request frame that can be used in the embodiment of the present invention has been described above, a detailed description thereof will be omitted below. However, according to the embodiment of the present invention, a path element may be included in the information element of the TDLS setting request frame, which is different from the existing TDLS setting procedure. As described above, this path element includes information indicating whether the STA that transmits the TDLS establishment request frame, that is, the path that the initiating STA wants to use after the end of the TDLS establishment procedure, that is, the AP path or the direct link path. Included. For example, if the initiating STA wishes to use the AP path after setting up the TDLS link, it may be set to '0', and may be set to '1' if it is desired to use the direct link path.

6, the peer STA that has received the TDLS setup request frame transmits a TDSL setup response frame to the initiating STA via the AP in response thereto (S12). In this case, the TDLS setup response frame is set to a value in which the TDLS packet type field indicates a TDLS setup response in the TDLS frame of FIG. 1. Therefore, the TDLS Setup Response is encapsulated in the form of a data frame and transmitted to the initiating STA via the AP.

Since the format of the TDLS configuration response frame that can be used in the embodiment of the present invention has been described above, a detailed description thereof will be omitted below. However, according to an exemplary embodiment of the present invention, a path element may be included in an information element of a TDLS configuration response frame, which is different from the existing TDLS configuration procedure. As described above, this path element includes information indicating whether the STA that transmits the TDLS setup response frame, that is, the path that the peer STA wants to use after the TDLS setup procedure is finished, that is, the AP path or the direct link path. May be included. For example, if the responding STA wishes to use the AP path after establishing the TDLS link, it may be set to '0', and if it is desired to use the direct link path, it may be set to '1'. However, embodiments of the present invention are not limited thereto, and the TDLS setup response frame includes information indicating the acceptance or rejection of the path information specified in the TDLS setup request frame in the path information or the TDLS setup response frame. Status information may also include information indicating rejection of the requested path.

6, the initiating STA transmits a TDSL configuration confirmation frame for the received TDSL configuration response frame to the peer STA via the AP (S13). In the TDLS setup confirmation frame, the TDLS packet type field is set to a value indicating a TDLS setup confirmation in the TDLS frame of FIG. 1, and is also encapsulated in the form of a data frame and transmitted through the AP. In the TDLS setup procedure, the management action frames are encapsulated and transmitted in the form of data frames without direct involvement of the AP, which is likely to be lost during transmission. Therefore, in the TDLS setting procedure, the initiating STA (first STA) transmits the TDLS setting confirmation frame with respect to the TDSL setting response frame from the peer STA (second STA).

As described above, according to the TDLS configuration procedure according to an embodiment of the present invention, the initiating STA and the peer STA that transmit and receive the TDLS configuration request and the TDLS configuration response may determine and determine the path to be used after the TDLS configuration process is finished through the path information. have. According to an aspect of the present embodiment, if any one terminal wants to use the AP path, that is, if the path field value of the path element is set to '0', the initiating STA and the peer STA must always determine the AP path. It can also be limited to use. In this case, since the initiating STA or the peer STA can operate in the power saving mode immediately after the TDLS is set, the TDLS link can be set even when any one STA operates in the power saving mode.

The embodiments of the present invention described in detail above are merely illustrative of the technical idea of the present invention, and should not be construed as limiting the technical idea of the present invention by the embodiments. The protection scope of the present invention is specified by the claims of the present invention described later.

1 is a block diagram showing the format of a TDLS frame.

2 is a diagram illustrating an example of a type of TDLS frame and a value corresponding thereto.

3 is a block diagram illustrating information included in an information field of a TDLS configuration request frame according to an embodiment of the present invention.

4 is a block diagram illustrating an example of a format of a path element that is one of information included in FIG. 3.

FIG. 5 is a block diagram illustrating information included in an information field of a TDLS configuration response frame according to an embodiment of the present invention.

6 is a message flow diagram illustrating a TDLS setup procedure according to an embodiment of the present invention.

Claims (9)

In the Tunneled Directed Link Setup (TDLS) setting procedure performed between the initiating station and the peer station, And the initiating station and the peer station determine by negotiating whether a transmission path to be used after the end of the TDLS setting procedure is a direct link path or an access point path. The TDLS setup procedure according to claim 1, wherein the transmission path is negotiated using a TDLS setup request frame and / or a TDLS setup response frame including a path element. The transmission path of claim 2, wherein the path element included in at least one of the TDLS establishment request frame and the TDLS establishment response frame indicates an access point path. TDLS setting procedure, characterized in that is determined by the access point path. 2. The TDLS setup procedure of claim 1, wherein the initiating station and / or the peer station can operate in a power saving mode after the end of the TDLS setup procedure. Transmit a Tunneled Direct Link Setup (TDLS) setup request frame including a first path element having information indicating a direct link path or an access point path to a peer station; In response to the TDLS setup request frame, receive a TDLS setup response frame including a second path element for which information indicating a direct link path or an access point path is set, and And transmitting a TDLS setup confirmation request frame in response to the TDLS setup response frame. 6. The transmission path of claim 5, wherein when a value included in at least one path element among the first path element and the second path element indicates an access point path, a transmission path after completion of the TDLS configuration procedure must be accessed. 7. TDLS setup procedure, characterized in that determined by the point path. 6. The TDLS setup procedure of claim 5, wherein the peer station can operate in a power saving mode after the end of the TDLS setup procedure. In a method for configuring a tunneled direct link setup (TDLS) setup request frame, The TDLS setup request frame includes a path element for indicating a direct link path or an access point path. In a method for configuring a tunneled direct link setup (TDLS) setup response frame, The TDLS setup response frame includes a path element for indicating a direct link path or an access point path.

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