KR102358147B1 - Method and apparatus of peer link setting, and method and apparatus of channel switching, in wireless mesh network - Google Patents

Abstract

A method and apparatus for establishing a mesh peer link in a wireless mesh network, and a method and apparatus for switching a channel are provided. The mesh peer link establishment method comprises the steps of: a first mesh station transmits a mesh peer open frame to a second mesh station; and the first mesh station transmits a mesh peer open frame to the second mesh station in response to the mesh peer open frame. and receiving a mesh peer confirmation frame from The mesh peer acknowledgment frame includes a VHT capabilities information element.

Description

METHOD AND APPARATUS OF PEER LINK SETTING, AND METHOD AND APPARATUS OF CHANNEL SWITCHING, IN WIRELESS MESH NETWORK

The present invention relates to a mesh network, and more particularly, to a method of providing a very high throughput (VHT) wireless LAN technology in a mesh network.

The IEEE 802.11s-based mesh network can be said to be a network that supports direct communication between multiple wireless devices with a relay function without going through an AP. From a functional point of view, the AP's Distribution System (DS) may be replaced with an interoperable wireless link or a multi-hop path between multiple APs. According to such a mesh network, since any one wireless device can establish a peer-to-peer wireless link that interacts with one or more neighboring wireless devices and/or APs, a more flexible wireless connection is possible. have.

In a mesh network, one wireless device may be connected to a plurality of other wireless devices to have a plurality of communication paths, and the communication path between these wireless devices is a wireless mesh link, a mesh peer link, or This is called a peer link. Such a wireless device is referred to as a mesh point (MP), but is not limited thereto. And, among MPs, a mesh access point (MAP) that performs an AP function in addition to the aforementioned relay function is referred to as a mesh access point (MAP).

Such a mesh network has advantages such as flexibility of network construction, reliability due to a detour path, and reduction of power consumption due to shortening of communication distance. More specifically, if the mesh network is used, it is possible to construct a flexible network between MPs even in a place where there is no existing communication network. In the mesh network, multiple detour paths can be secured by connecting multiple MPs to each other, so that even if one MP fails, data can be transmitted through other paths. In addition, in the mesh network, even if the communication area (coverage) of one MP is not wide, communication can be performed via an adjacent MP, so that long-distance communication is possible even with low power.

Currently, IEEE 802.11n wireless LAN technology is supported in IEEE 802.11s-based mesh networks. IEEE 802.11n is a relatively recently established standard technology to overcome the limitation of communication speed, which is a weakness of wireless LAN, and is designed to increase network speed and reliability and expand operation coverage of wireless network. . More specifically, IEEE 802.11n supports High Throughput (HT) with data throughput of up to 600 Mbps, and employs multiple antennas at the transmitter and/or receiver to minimize transmission errors and optimize data rates. It is based on MIMO (Multiple Inputs and Multiple Outputs) technology.

As the spread of wireless LANs is activated and applications using them are diversified, there is a need for a new wireless LAN technology to support a processing rate higher than the data processing speed supported by IEEE 802.11n in recent years. As a successor technology of IEEE 802.11n, IEEE 802.11ac VHT wireless LAN technology supporting very high throughput (VHT) has been newly proposed. VHT wireless LAN supports data processing speed of 1 Gbps or higher in MAC service access point (SAP). The name of the VHT wireless LAN is arbitrary, but in order to provide a data throughput of 1 Gbps or more, a feasibility test is currently being conducted on a VHT wireless LAN system using 4X4 MIMO and 80 MHz channel bandwidth.

Accordingly, there is a need for a method capable of supporting the VHT wireless LAN technology even in an IEEE 802.11s-based mesh network.

Republic of Korea Patent Publication No. 10-2010-0083703

A method of exchanging VHT-related capability information between MPs in order to use VHT WLAN technology in a wireless mesh network is provided.

A method for using a wide bandwidth channel switch function of 80 MHz or more provided by VHT wireless LAN technology in a wireless mesh network and a method for controlling transmission power of VHT are provided.

According to an aspect of the present invention, a method for establishing a mesh peer link in a wireless mesh network is provided. The method includes the steps of: a first mesh station transmitting a mesh peer open frame to a second mesh station; and in response to the mesh peer open frame, the first mesh station sends a mesh peer from the second mesh station to the second mesh station. Receiving a confirmation frame (Mesh Peering Confirm Frame), wherein the first mesh station and the second mesh station support a very high throughput (VHT), and the mesh peer open frame and the mesh peer The acknowledgment frame includes a VHT capabilities information element.

The mesh peer open frame and the mesh peer confirmation frame may further include a VHT operation information element.

Before the first mesh station transmits the mesh peer open frame, passive scanning or active scanning may be performed to discover the second mesh station.

The VHT capability information element includes an information element indicating a maximum MAC Protocol Data Unit (MPDU) length, an information element indicating a channel bandwidth supported by a station, and whether to receive a packet encoded with a Low Density Parity Check (LDPC). An information element indicating whether to support a short guard interval, an information element indicating whether to support reception of PLCP Protocol Data Unit (PPDU) using STBC (Space Time Block coding), and a TXOP ( Transmission Opportunity) may include at least one of information elements indicating whether the power save mode is supported.

The VHT operation information element may include at least one of an information element indicating an operation channel bandwidth and an information element defining a channel center frequency.

According to another aspect of the present invention, a wireless device supporting a method of establishing a mesh peer link in a wireless mesh network is provided. The wireless device includes a processor for generating and processing frames; and

and a transceiver connected to the processor to transmit and receive frames generated by the processor, wherein the processor generates a mesh peer open frame and transmits it to a mesh station adjacent to the wireless device, the mesh peer open The frame includes a VHT capability information element, and receives a mesh peer acknowledgment frame from the neighboring mesh station in response to the mesh peer open frame, wherein the mesh peer acknowledgment frame includes a VHT capability information element.

The mesh peer open frame and the mesh peer confirmation frame may further include a VHT operation information element.

According to another aspect of the present invention, a method for switching a channel in a wireless mesh network is provided. In the method, a first mesh station to switch from a first channel to a second channel transmits a Channel Switch Announcement Frame to a second mesh station, wherein the first mesh station and the second mesh station are Very high throughput (VHT) is supported, and the channel switch announcement frame includes a Wide Bandwidth Channel Switch Element field and a Mesh Channel Switch Parameters Element field.

The wideband channel switch element field may indicate switching to a channel bandwidth wider than 40 MHz, and the mesh channel switch parameter element field may indicate switching from the first channel to the second channel in the wireless mesh network.

According to another aspect of the present invention, a wireless device supporting a channel switch method in a wireless mesh network is provided. The wireless device includes a processor for generating and processing a frame, and a transceiver connected to the processor to transmit and receive the frame generated by the processor, wherein the wireless device operates from a first channel to a second channel , the processor generates a channel switch announcement frame, wherein the channel switch announcement frame includes a wideband channel switch element field and a mesh channel switch parameter element field.

The wideband channel switch element field may indicate switching to a channel bandwidth wider than 40 MHz, and the mesh channel switch parameter element field may indicate switching from the first channel to the second channel in the wireless mesh network.

According to another aspect of the present invention, a method for determining a maximum transmit power in a wireless mesh network is provided. The method determines a Regulatory Maximum Transmit Power (RMTP) regulated by each country for a channel currently being used by the mesh station, wherein the RMTP is received from a neighboring mesh station in the wireless mesh network or a station in another WLAN system. a smaller value of the first RMTP and the second RMTP based on a first RMTP obtained from a Country Element and a second RMTP for a channel in a current Regulatory domain; and determining a local maximum transmit power (LMTP) for a channel currently being used by the mesh station, wherein the LMTP is a country element received from a neighboring mesh station in the wireless mesh network or a station in another wireless LAN system. and a first LMTP obtained from a Power Constraint Element, a VHT Transmit Power Envelope Element received from a neighboring mesh station in the wireless mesh network or a station in another WLAN system, and extended power restriction Based on the second LMTP obtained from the Extended Power Constraint Element and the third LMTP for the channel in the current Regulatory domain, it is the smaller of the first LMTP, the second LMTP, and the third LMTP. .

The mesh station may announce the RMTP through a beacon frame and a probe response frame using a country element.

The mesh station uses a combination of Country Element and Power Constraint Element, or a combination of VHT Transmit Power Envelope Element and Extended Power Constraint Element. Thus, the LMTP may be announced through the beacon frame and the probe response frame.

In a wireless mesh network, VHT wireless LAN-based wireless transmission is possible between MPs, and a broadband channel switch function of the VHT wireless LAN can be provided. Therefore, it is possible to provide improved performance compared to the conventional wireless mesh network.

1 is a diagram illustrating an example of a wireless mesh network to which an embodiment of the present invention can be applied.
2 is a message flow diagram illustrating a mesh peer link establishment procedure according to an embodiment of the present invention.
3 is a diagram illustrating an example of information included in a mesh peer open frame used in a mesh peer link establishment procedure according to an embodiment of the present invention.
4 is a diagram illustrating an example of information included in a mesh peer confirmation frame used in a mesh peer link establishment procedure according to an embodiment of the present invention.
5 is a diagram illustrating an example of a field included in a VHT capability information element according to an embodiment of the present invention.
6 is a diagram illustrating an example of a field included in a VHT operation information element according to an embodiment of the present invention.
7 is a diagram illustrating a format of a channel switch announcement frame for supporting a wideband channel switch function according to an embodiment of the present invention.
8 is a diagram illustrating a mesh BSS to which transmit power control is applied.
9 is a block diagram illustrating a wireless device to which an embodiment of the present invention can be applied.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail so that those of ordinary skill in the art can easily implement them with reference to the accompanying drawings. In addition, the present invention is not limited to the embodiments described below, and may be applied in various different forms within the scope of the technical spirit of the present invention.

1 is a diagram illustrating an example of a wireless mesh network to which an embodiment of the present invention can be applied.

Referring to FIG. 1 , a wireless mesh network includes one or more STAs 131 , 132 , 133 , 134 and one or more wireless devices, that is, MPs 111 , 121 , 122 , 123 . Among the MPs, reference numerals 121 and 122 have STAs 131 , 132 , 133 , and 134 associated with them, and thus become MPs that simultaneously perform the functions of an AP, that is, a MAP. In addition, an MP of reference number 111 is an MP connected to an external network by wire or wirelessly, which is referred to as a mesh portal.

The STAs 131 to 134 are arbitrary functional media including a medium access control (MAC) and a physical layer interface for a wireless medium that comply with the provisions of the IEEE 802.11 standard, and non-AP stations (Non- AP Station). In addition, the STAs 131 to 134 inform the MAP 121 or 122 to which they are combined of the multicast subscription information to which they have subscribed. In addition to the name of a radio station, the STA may also be called a Wireless Transmit/Receive Unit (WTRU), User Equipment (UE), a Mobile Station (MS), or a Mobile Subscriber Unit. can

The MPs 111, 121, 122, and 123 are entities constituting a wireless mesh network, and are one of the functional entities of IEEE 802.11 including media access control and a physical layer interface conforming to IEEE 802.11 standards. The MPs 111 , 121 , 122 , and 123 are wireless devices supporting mesh services, and the mesh services include various services that enable direct communication between MPs constituting the mesh network. Communication between two MPs for providing a mesh service, eg, an MP of reference number 121 and an MP of reference number 123, is performed through a mesh link or a peer link, which is a direct link established between the two MPs. . According to an embodiment of the present invention, the MP (111, 121, 122, 123) supports one or more VHT MAC and PHY characteristics to achieve 1Gbps or more ultra-high-speed throughput.

Among the MPs 111 , 121 , 122 , and 123 , an MP that performs a function as an AP is specifically referred to as a MAP. Accordingly, the MAPs 121 and 122 perform a function as an AP for an associated station connected to the MAP in addition to the above-described MP function. The AP may be referred to as a centralized controller, a base station (BS), a Node-B, or a site controller, in addition to the name of an access point.

In the wireless mesh network shown in FIG. 1, an independent network composed of MPs 111, 121, 122, and 123 supporting a mesh service is called a mesh basic service set (BSS). The BSS is a set of stations (STAs) that can communicate with each other through successful synchronization, and is not a concept indicating a specific area. The MPs 111, 121, 122, and 123 in the mesh BSS may be referred to as mesh stations (Mesh STAs).

In addition, the mesh BSS may be connected to an external network by wire or wirelessly to configure a wireless LAN system. For example, it may be connected to a network such as an infrastructure BSS (infrastructure BSS) and an independent BSS (IBSS) to communicate.

The infrastructure BSS includes one or more non-AP STAs, an access point that is an STA that provides a distribution service, and a distribution system (DS) that connects a plurality of access points. In the infrastructure BSS, the AP STA manages the non-AP STAs of the BSS. On the other hand, the independent BSS is a BSS operating in an ad-hoc mode. Since the IBSS does not include the AP VHT STA, there is no centralized management entity that performs a centralized management function. That is, in IBSS, Non-AP STAs are managed in a distributed manner. In the IBSS, all STAs may be mobile stations, and access to the DS is not allowed to form a self-contained network.

In order to provide ultra-high-speed wireless transmission of 1 Gbps or more by utilizing VHT wireless LAN technology in mesh BSS, MPs (hereinafter referred to as mesh STAs) constituting mesh BSS according to an embodiment of the present invention support the VHT wireless LAN function. It should be able to exchange information indicating whether it is an STA. In addition, the mesh STA should be able to transmit and receive data using a wide bandwidth channel of 80 MHz or more provided by the VHT wireless LAN technology. Hereinafter, methods in which mesh STAs can use VHT WLAN technology in the aforementioned mesh BSS will be described in detail along with embodiments.

2 is a message flow diagram illustrating a mesh peer link establishment procedure according to an embodiment of the present invention. The mesh peer link establishment procedure of FIG. 2 is performed after a mesh discovery process.

The mesh discovery process may be referred to as a process in which a mesh STA that wants to establish a peer link with another mesh STA finds a candidate mesh STA or a neighbor mesh STA that can become a peer mesh STA. Here, mesh STAs constituting the mesh BSS have a predetermined mesh profile. Accordingly, the mesh discovery process is a process of finding a mesh STA that matches the mesh profile or can match the mesh profile. The mesh profile includes a mesh identifier, a path selection protocol identifier, a path selection metric identifier, a congestion control mode identifier, and the like.

There are two methods of mesh discovery process. The first method is a passive scan method, and uses a mesh beacon frame transmitted from another mesh STA. That is, a mesh STA that wants to participate in the mesh BSS receives a mesh beacon frame periodically transmitted from another mesh STA, and finds a candidate mesh STA with which it wants to peer. The second method is an active scan method. A mesh STA that wants to participate in the mesh BSS first transmits a mesh probe request frame. When the mesh STA that has received the mesh probe request frame intends to establish a peer link with the transmitting mesh STA, it transmits a mesh probe response frame to the transmitting mesh STA.

The mesh beacon frame or the mesh probe request/response frame includes mesh ID information. The mesh beacon frame or mesh probe response frame includes mesh configuration information. A mesh STA that wants to establish a peer link uses such mesh ID information and mesh configuration information to know the mesh profile information of another mesh STA (mesh STA that transmitted a mesh beacon frame or a mesh STA that transmitted a mesh response frame). can In particular, the mesh configuration information is used to identify information other than the mesh ID from among the information constituting the mesh profile.

When neighboring mesh STAs are discovered through the aforementioned mesh discovery process, the mesh STA attempts a mesh link establishment procedure with the discovered neighboring mesh STAs. The mesh link establishment procedure refers to establishing a logical link between mesh STAs, and is also referred to as a peering procedure. The mesh BSS establishes a peer link through such a peering procedure, and can transmit and receive data frames only between mesh STAs that have established the peer link. In order to establish a mesh peer link between mesh STAs, a mesh peer open frame and a mesh peer confirmation frame are exchanged.

A process in which the first mesh STA 10 and the second mesh STA 20 establish a peer link will be described with reference to FIG. 2 .

The first mesh STA 10 transmits a first mesh peer open frame to the second mesh STA 20 , and in response thereto receives a first mesh peer confirmation frame from the second mesh STA 20 . In addition, the second mesh STA 20 also transmits a second mesh peer open frame to the first mesh STA 10 , and receives a second mesh peer confirmation frame from the first mesh STA 10 in response thereto.

There is no restriction on the order in which the first mesh peer open/confirm frame and the second mesh peer open/confirm frame are exchanged. For example, the first mesh STA 10 may transmit the first mesh peer open frame before or after receiving the second mesh peer open frame from the second mesh STA 20, and also receive The second mesh peer open frame may be transmitted before or after transmitting the second mesh peer acknowledgment frame in response to the second mesh peer open frame to the second mesh STA 20 .

According to an embodiment of the present invention, the first and second mesh peer open frames exchanged between the first mesh STA 10 and the second mesh STA 20 and the first and second mesh peer confirmation frames include a high-speed throughput service and It includes capability information of related wireless devices, that is, VHT capability information. That is, the mesh peer open frame and mesh peer confirmation frame used when establishing the peer link in the mesh BSS include capability information related to the VHT WLAN function supported by the mesh STA.

3 is a diagram illustrating an example of information included in a mesh peer open frame used in a mesh peer link establishment procedure according to an embodiment of the present invention. As described above, the mesh peer open frame is used to initiate the mesh link establishment procedure.

The mesh peer open frame according to the present invention includes all of the existing IEEE 802.11s mesh peer open frame action field items. For example, it includes category information, action value information, capability information, and supported rate information. In addition, when a predetermined condition is satisfied, extended support rate information (Extended Support Rate), power capability information (Power Capability), support channel information (Supported Channel), RSN (Robust Security Network) information, mesh identifier information (Mesh ID) , mesh configuration information (Mesh Configuration), mesh peering management information (Mesh Peering Management), may include MIC (Message Integration Code) information.

In addition, when the mesh STA transmitting the mesh peer open frame supports the VHT function, as shown in FIG. 3 , the mesh peer open frame includes a VHT Capabilities information element and a VHT Operation information. elements are included.

The VHT capability information element is for notifying the counterpart mesh STA of the fact that the mesh STA supports VHT MAC/PHY, and also for notifying the counterpart STA of VHT-related capabilities (VHT capabilities) supported by the mesh STA. The VHT operation information element is for controlling the operation of the mesh STA supporting the VHT WLAN in the mesh BSS.

The field order or order number of the VHT capability information and the VHT operation information shown in FIG. 3 is an example, and the field order or the order number may be changed as needed.

4 is a diagram illustrating an example of information included in a mesh peer confirmation frame used in a mesh peer link establishment procedure according to an embodiment of the present invention. As described above, the mesh peer acknowledgment frame is a frame transmitted in response to the received mesh peer open frame, and is used to confirm mesh peering.

The mesh peer acknowledgment frame according to the present invention includes all of the existing IEEE 802.11s mesh peer acknowledgment frame action field items. For example, a Category information element, an Action Value element, a Capability element, an Association Identifier (AID) information element, and a Supported Rate element are included. And when a predetermined condition is satisfied, extended support rate information (Extended Support Rate) element, RSN (Robust Security Network) information element, mesh identifier information (Mesh ID) element, mesh configuration information (Mesh Configuration) element, mesh peering management It may include an information (Mesh Peering Management) element and a MIC (Message Integration Code) information element.

In addition, if the mesh STA transmitting the mesh peer confirmation frame supports the VHT function, as shown in FIG. 4 , the mesh peer confirmation frame includes a VHT Capabilities information element and a VHT Operation information. elements are included.

* The VHT capability information element is to inform the other mesh STA that the mesh STA supports VHT MAC/PHY and also inform the other mesh STA of the VHT-related capabilities (VHT capabilities) it supports. The VHT operation information element is for controlling the operation of the mesh STA supporting the VHT WLAN in the mesh BSS.

The field order or order number of the VHT capability information and the VHT operation information shown in FIG. 4 is an example, and the field order or the order number may be changed as needed.

Hereinafter, field configurations of the VHT capability information element and the VHT operation information element transmitted by being included in the mesh peer open frame and the mesh peer confirmation frame will be described. The names and construction order of fields included in the following VHT capability information element and VHT operation information element are arbitrary, and the present invention is not limited to the name of each field and the construction order of the fields.

5 is a diagram illustrating an example of a field included in a VHT capability information element according to an embodiment of the present invention.

5, the VHT capability information element 400 is a Maximum MPDU Length (411) indicating a maximum MAC Protocol Data Unit (MPDU) length, a Supported Channel Width Set (412) indicating a channel bandwidth supported by the STA. , Rx LDPC 413 indicating whether to receive a packet encoded by LDPC (Low Density Parity Check), Short GI (414, 415) indicating whether to support Short Guard Interval, at least 2x1 STBC Tx STBC 416 indicating whether to support transmission, Rx STBC 417 indicating whether to support reception of PLCP Protocol Data Unit (PPDU) using space time block coding (STBC), supports operation as a SU beamformer SU Beamformer Capable (418) indicating whether or not, SU Beamformee Capable (419) indicating whether operation as a SU beamformer is supported, Compressed Steering Number indicating the maximum number of supported beamformer antennas when SU Beamformee Capable of Beamformer Antennas Supported (420), Number of Sounding Dimensions (421) indicating the maximum value of the TXVECTOP parameter NUM_STS when SU Beamformer Capable, MU Beamformer Capable (422) indicating whether to support the operation as an MU beamformer, MU Beamformee Capable (423) indicating whether to support the operation as a MU beamformee, whether the AP supports the VHT TXOP (Transmission Opportunity) power save mode or non-AP STA indicating whether the VHT TXOP power save mode VHT TXOP PS (424), STA is VHT variant +HTC-VHT Capable (425) indicating whether HT Control field reception is supported, Maximum A-MPDU Length Exponent (426) indicating the maximum length of A-MPDU that the STA can receive, STA is VHT modified HT VHT Link Adaptation Capable (427) indicating whether link adaptation is supported using the Control field, Rx Antenna Pattern Consistency (428) indicating whether an Rx antenna pattern change is possible, and Tx antenna pattern change. It may include at least one of the Tx Pattern Consistency (429).

All fields that may be included in the above-described VHT capability information element 400 may be included, or only some of the fields may be included as necessary.

6 is a diagram illustrating an example of a field included in a VHT operation information element according to an embodiment of the present invention.

Referring to Figure 6, the VHT operation information element 500 is a Channel Width (511) indicating the operating channel bandwidth, a channel center frequency for 80 MHz or 160 MHz VHT BSS and a segment 0 channel center frequency for 80 + 80 MHz VHT BSS. It may include at least one of Channel Center Frequency Segment 0 (512) that defines and Channel Center Frequency Segment 1 (513) that defines the segment 1 channel center frequency for 80+80 MHz VHT BSS.

All of the fields that may be included in the above-described VHT operation information element 500 may be included, or only some of the fields may be included as necessary.

In the conventional 802.11s-based mesh BSS, even if a mesh STA (hereinafter referred to as a VHT mesh STA) supporting a VHT wireless LAN function exists, whether a VHT service is supported between mesh STAs, and the VHT-related capabilities supported by the STA, etc. information could not be exchanged. However, VHT mesh STAs according to an embodiment of the present invention may exchange VHT service related information when establishing a mesh peer link. That is, as described above in FIGS. 3 and 4, a function corresponding to a subset of VHT features is used between VHT mesh STAs that have set mesh peering through the extension of the mesh peer open frame and the mesh peer confirmation frame. .

Meanwhile, when mesh STAs forming a mesh peer link in the mesh BSS or trying to form a mesh peer link try to change a channel, it is necessary to notify the peer mesh STA of the fact. When communication is performed through the peer link as in the mesh BSS, since the channel is only available between the same mesh STAs, if the mesh STA that wants to change the channel does not notify the peer mesh STA of the fact, the peer mesh STA is The peer link is unilaterally released from the mesh STA. Therefore, when the mesh STA intends to change the channel, it is desirable to first notify the peer mesh STA of the fact to give the peer mesh STA an opportunity to determine whether to continue maintaining or release the peer link. Accordingly, the mesh STA that intends to change the channel transmits a Channel Switch Announcement Frame to the peer mesh STA as a method of notifying the fact.

When a VHT mesh STA according to an embodiment of the present invention wants to change a channel, it must be able to use a channel bandwidth of 80 MHz or more provided by 802.11ac VHT wireless LAN technology. Therefore, according to an embodiment of the present invention, when the VHT mesh STA changes to a new channel, information for supporting a wide bandwidth channel switch function is included in the channel switch announcement frame.

7 is a diagram illustrating a format of a channel switch announcement frame for supporting a wideband channel switch function according to an embodiment of the present invention. The channel switch announcement frame is used to notify when the AP in the BSS or the mesh STA in the mesh BSS is changed to a new channel.

Referring to FIG. 7 , a channel switch announcement frame 300 includes a Category field 310 , an Action field 320 , a Channel Switch Announcement Element field 330 , and a subchannel offset. It includes a Secondary Channel Offset Element field 340 .

The category field 310 may include a value indicating a category to which the channel switch announcement frame 300 belongs, for example, a management category. The action field 320 may include a value indicating specific action content by the channel switch notification frame 300 , for example, a spectrum management action. The channel switch notification element field 330 is used by the mesh STA in the mesh BSS, and when a new channel is changed to another mesh STA, the channel number of the new channel, a priority value determined by the combination of new channels, etc. may include The sub-channel offset element field 340 is for designating a sub-channel number in a channel to be changed, and may specify a sub-channel by using a relative position to the main channel.

When the VHT mesh STA according to an embodiment of the present invention wants to change a channel, as shown in FIG. 7 , the channel switch announcement frame 300 is a mesh channel switch parameter element field 350 , and a Wide Bandwidth Channel Switch Element field 360 .

The mesh channel switch parameter element field 350 is a field for supporting channel switch in the mesh BSS, and is included in the channel switch announcement frame 300 when the VHT mesh STA changes from the first channel to the second channel in the mesh BSS. If it is changed to a channel other than the mesh BSS, it is not included in the channel switch announcement frame 300 .

The wideband channel switch element field 360 is a field for supporting the wideband channel switch of the VHT WLAN technology, and is for informing other mesh STAs that the VHT mesh STA switches to a channel bandwidth wider than 40 MHz. That is, when the VHT mesh STA changes to a channel bandwidth wider than 40 MHz, the wideband channel switch element field 360 may be included in the channel switch announcement frame 300 .

The channel switch announcement frame 300 according to an embodiment of the present invention may further include a New VHT Transmit Power Envelop Element field 370 . The new VHT transmit power envelope element field 370 may be configured in the same form as the existing VHT transmit power envelope element, and includes a unique value of LMTP unit interpretation (Local Maximum Transmit Power Units Interpretation). LMTP is the maximum transmit power that the BSS can use.

A new VHT Transmit Power Envelope Element field 370 indicates the Local Maximum Transmit Power (LMTP) for the BSS of the specified bandwidth with the specified units interpretation after changing the channel.

The order of the fields in the channel switch announcement frame 300 shown in FIG. 7 and the number of octets or the length of the fields are examples, and the order of the fields and the length of the fields can be changed as needed. In addition, the channel switch announcement frame 300 may further include fields other than the fields shown in FIG. 7 as needed, or the fields shown in FIG. 7 are not always included.

By using the channel switch announcement frame according to the embodiment of the present invention, even if the VHT mesh STA changes a channel as needed, it guarantees that a bandwidth of 80 MHz or more can be used, thereby obtaining more improved performance in the mesh BSS according to the present invention.

The mesh BSS according to an embodiment of the present invention reduces mutual interference with other networks, such as BSS, IBSS, Personal Basic Service Set (PBS), etc. and transmits power for the channel currently being used to support a bandwidth of 80 MHz or more. control Accordingly, by allowing the mesh STA to adaptively adjust the transmission power, it is possible to efficiently manage radio resources and reduce power consumption of the mesh STA, thereby reducing battery consumption.

8 is a diagram illustrating a mesh BSS to which transmit power control is applied.

* Referring to FIG. 8 , the mesh BSS to which transmit power control is applied may be divided into three transmit power ranges: RMTP, LMTP, and Current Transmit Power (CTP).

RMTP (Regulatory Maximum Transmit Power) is the maximum transmit power prescribed by each country.

LMTP (Local Maximum Transmit Power) is the maximum transmit power that can be used in the corresponding mesh BSS, and is set to a value smaller than RMTP. This is to protect other radio wave sharing systems by limiting the maximum output of the corresponding mesh BSS.

Current transmission power used between mesh STAs is set to a value less than or equal to LMTP.

The above-described transmission power control method determines the RMTP and LMTP for the channel currently being used by the mesh STA by using a beacon frame and a probe response frame transmitted and received between the mesh STAs, and through this, the maximum transmit power is determined. control In addition, according to the present invention, in order to provide a wide channel bandwidth supported by the VHT WLAN, the maximum transmit power is controlled using a VHT transmit power envelope element and an extended power constraint element. do.

Hereinafter, a method in which the mesh STA determines the RMTP and the LMTP to control the maximum transmission power according to an embodiment of the present invention will be described in detail.

The mesh STA determines the smaller RMTP value among the following (i) and (ii) as the RMTP value for the currently used channel.

(i) a neighboring mesh STA of the mesh BSS or a STA of another WLAN system (eg, an AP in the BSS, a PBSS Central Point (PCP) in the PBSS, other STAs in the IBSS, etc.) RMTP

(ii) RMTP for a channel in the current Regulatory domain obtained from other sources

The mesh STA determines the smaller LMTP value among the following (i), (ii) and (iii) as the LMTP value for the currently used channel.

(i) a neighboring mesh STA of the mesh BSS or a STA of another WLAN system (eg, an AP in the BSS, a PCP in the PBSS, another STA in the IBSS) received from a country element (Country Element) and Power Constraint Element ) obtained from LMTP

(ii) a VHT transmit power envelope element received from a neighboring mesh STA of the mesh BSS or an STA of another WLAN system (eg, an AP in the BSS, a PCP in the PBSS, another STA in the IBSS) and the extended LMTP from Extended Power Constraint Element

(iii) LMTP for channels in the current Regulatory domain as obtained from other sources

Here, the country element is information indicating that there is a regulation of transmission power for each frequency band in each country. The Power Constraint Element is for defining LMTP. The VHT transmit power envelope element (Transmit Power Envelope Element) indicates the maximum transmit power for various channel bandwidths of the VHT mesh STA. An Extended Power Constraint Element defines the LMTP for each channel bandwidth.

In the above description, the method for the mesh STA in the mesh BSS to determine the RMTP and the LMTP has been described, but the present invention is not limited thereto. For example, it is applicable to STA in BSS, STA in IBSS, PCP in PBSS, and the like.

Meanwhile, the mesh STA should announce the RMTP for the currently used channel, that is, an operating channel, determined above using a country element in a beacon frame and a probe response frame.

In addition, the mesh STA determines the LMTP for the currently used channel, that is, an operating channel, a combination of a country element and a power constraint element, or a VHT transmission power envelope element (Transmit). A beacon frame and probe response frame shall be advertised using one of a combination of Power Envelope Element and Extended Power Constraint Element.

Here, not only the mesh STA, but also the STAs in other wireless systems, such as the AP in the BSS and the STA in the IBSS, may announce the RMTP and LMTP determined by the above-described transmission power control method through the beacon frame and the probe response frame.

The RMTP and LMTP determined by the above-described transmission power control method may be changed during the lifetime of the mesh BSS and the infrastructure BSS, but it is necessary to determine how often and how much the maximum value changes in consideration of the stability of the network. RMTP and LMTP do not change during IBSS survival.

The VHT mesh STA according to an embodiment of the present invention includes a mesh control field in a data frame to provide a mesh function. And the maximum length of the frame body of the VHT mesh STA is calculated in consideration of the length of the mesh control field.

9 is a block diagram illustrating a wireless device to which an embodiment of the present invention can be applied. The wireless device may be a mesh STA.

Referring to FIG. 9 , the wireless device 30 includes a processor 32 , a memory 34 , and a transceiver 36 .

The transceiver 36 transmits/receives radio signals, but a physical layer of IEEE 802.11 is implemented. For example, a physical layer supporting VHT may be implemented.

The processor 32 is functionally connected to the transceiver 36 to implement the MAC layer of IEEE 802.11.

The processor 32 generates and transmits a mesh peer open/confirmation frame including the VHT capability information element and the VHT operation information element proposed by the present invention, or a VHT capability information element included in the received mesh peer open/confirmation frame, and It interprets the field values of the VHT operation information element so that the wireless device 30 can support the VHT function.

The processor 32 generates and transmits a channel switch announcement frame including a wideband channel switch element and a mesh channel switch parameter element to support the wideband channel switch function proposed by the present invention. Alternatively, information related to a channel switch operation may be obtained by analyzing field values included in the received switch announcement frame.

The processor 32 may be implemented to control the maximum transmission power by determining the RMTP and the LMTP for the channel currently being used proposed by the present invention.

That is, the processor 32 may be configured to implement the above-described embodiments of the present invention.

Processor 32 and/or transceiver 36 may include an application-specific integrated circuit (ASIC), other chipset, logic circuitry, and/or data processing device. Memory 34 may include read only memory (ROM), random access memory (RAM), flash memory, memory cards, storage media, and/or other storage devices. When the embodiment is implemented in software, the above-described technique may be implemented as a module (process, function, etc.) that performs the above-described function. Modules may be stored in memory 34 and executed by processor 32 . The memory 34 may be internal or external to the processor 32 , and may be coupled to the processor 32 by a variety of well-known means.

The above description is merely illustrative of the technical spirit of the present invention, and various modifications and variations will be possible without departing from the essential characteristics of the present invention by those skilled in the art to which the present invention pertains. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention, but to explain, and the scope of the technical spirit of the present invention is not limited by these embodiments. The protection scope of the present invention should be construed by the claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

Claims (12)

A method of operating a station (STA) in a wireless LAN system, the method comprising:
determining whether a Very High Throughput (VHT) function is supported;
generating a mesh peering open frame at the station based on determining whether the VHT function is supported;
transmitting the mesh peer open frame to another station; and
Receiving a mesh peering confirm frame from the other station,
When the station supports the VHT function, the mesh peer open frame includes a field indicating a VHT capability information element for the station and a field indicating a VHT operation information element for the station,
If the other station supports the VHT function, the mesh peer acknowledgment frame includes a field indicating a capability information element for the other station and a field indicating a VHT operation information element for the other station,
The VHT capability information element for the station includes information related to a single-user beamforming capability, information related to a multi-user beamforming capability, and information related to a beamforming capability related to sounding.
According to claim 1,
The VHT capability information element, the method further comprising a maximum Media Access Control Protocol Data Unit (MPDU) length (length) and a supported channel bandwidth set (supported channel width set).
3. The method of claim 2,
The VHT operation information element, a method of indicating a channel bandwidth (Channel Width) and a channel center frequency (channel center frequency).
According to claim 1,
The mesh peer confirmation frame includes the VHT capability information element and the VHT operation information element.
A communication device in a wireless LAN system, comprising:
transceiver; and
a processor connected to the transceiver;
The processor is
Determining whether the communication device supports a VHT (Very High Throughput) function,
generating a mesh peer open frame based on determining whether the communication device supports the VHT function;
Control to transmit the mesh peer open frame to a station (station, STA),
circuitry for controlling to receive a mesh peer acknowledgment frame from the station;
When the communication device supports the VHT function, the mesh peer open frame includes a field indicating a VHT capability information element for the communication device and a field indicating a VHT operation information element for the communication device,
If the station supports the VHT function, the mesh peer acknowledgment frame includes a field indicating a capability information element for the station and a field indicating a VHT operation information element for the station,
The VHT capability information element for the communication device includes information related to a single-user beamforming capability, information related to a multi-user beamforming capability, and information related to a beamforming capability related to sounding.

6. The method of claim 5,
The VHT capability information element, the maximum MPDU (Media Access Control Protocol Data Unit) length (length) and a supported channel bandwidth set (supported channel width set) communication device further comprising.
7. The method of claim 6,
The VHT operation information element, a communication device indicating a channel bandwidth (Channel Width) and a channel center frequency (channel center frequency).
6. The method of claim 5,
The mesh peer acknowledgment frame includes the VHT capability information element and the VHT operation information element.
In a station (STA) in a wireless LAN system,
transceiver; and
a processor connected to the transceiver;
The processor is
determining whether the station supports the VHT function;
generate a mesh peer open frame based on determining whether the station supports the VHT function;
Control the station to transmit the mesh peer open frame to another station,
Control the station to receive a mesh peer acknowledgment frame from the other station,
When the station supports the VHT function, the mesh peer open frame includes a field indicating a VHT capability information element for the station and a field indicating a VHT operation information element for the station,
If the other station supports the VHT function, the mesh peer confirmation frame includes a field indicating a capability information element for the other station and a field indicating a VHT operation information element for the other station,
The VHT capability information element for the station includes information related to a single-user beamforming capability, information related to a multi-user beamforming capability, and information related to a beamforming capability related to sounding.
10. The method of claim 9,
The VHT capability information element, the station further comprising a maximum Media Access Control Protocol Data Unit (MPDU) length (length) and a supported channel bandwidth set (supported channel width set).
11. The method of claim 10,
The VHT operation information element is a station indicating a channel bandwidth (Channel Width) and a channel center frequency (channel center frequency).
10. The method of claim 9,
The mesh peer confirmation frame includes the VHT capability information element and the VHT operation information element.

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