KR20160056287A - Method for transmitting frame, method for receiving frame, and apparatus implementing the same method - Google Patents

Abstract

The present invention relates to a frame transmission method of a device in a wireless local area network, comprising: a step of generating a frame, which includes basic service set (BSS) identification information; and a step of transmitting the frame. The frame is a request-to-send (RTS) frame or a clear-to-send (CTS) frame. According to an embodiment of the present invention, a wireless local area network device is able to improve a possibility to receive a packet transmitted by the same BSS.

Description

Technical Field [0001] The present invention relates to a frame transmission method, a frame reception method, and a device implementing the same.

The present invention relates to a frame transmission / reception method in a wireless local area network (WLAN) (hereinafter referred to as "wireless LAN").

Wireless LANs are being standardized under the name of "Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications" in IEEE P11. The IEEE 802.11a standard (IEEE Std 802.11a-1999), which supports the 2.4 GHz band, was released in 1999, and the IEEE Std 802.11g-2003, which supports the 5 GHz band in 2003, These standards are called legacy. The IEEE 802.11n standard (IEEE Std 802.11n-2009) for higher throughput (HT) was released in 2009, and the IEEE 802.11ac standard for very high throughput (VHT) enhancement IEEE 802.11ac-2013) was released in 2013. Currently, the IEEE 802.11ax task group is developing a high efficiency WLAN (HEW) that can improve system throughput in high density environments.

The frequency band of the wireless LAN is unlicensed, and various devices exist and cause interference. The WLAN device uses a Carrier Sense Multiple Access / Collision Avoidance (CSMA / CA) scheme, which communicates only when a channel is not in use to prevent collision with other devices. The wireless LAN device transmits a request to send (RTS) frame or a clear to send (CTS) frame to occupy the channel, and informs the neighboring device of the channel occupancy period. The neighbor device sets a network allocation vector (NAV) based on the duration field of the RTS / CTS frame and defer the media connection for the NAV period. However, in dense networks in which a plurality of basic service sets (BSSs) are overlapped, the WLAN device can receive RTS / CTS frames transmitted from an overlapped BSS (OBSS). However, if the wireless LAN device sets the NAV unconditionally for the RTS / CTS frame transmitted from the OBSS, there is a problem that the wireless LAN device loses the transmission opportunity, and the resource reuse between the neighboring BSSs decreases, resulting in lower system yield.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a frame transmission method and a frame reception method for transmitting BSS (Basic Service Set) information to a frame and identifying BSS information included in the frame.

A method of transmitting a frame of a device in a wireless local area network (WLAN) according to an embodiment of the present invention includes generating a frame including a Basic Service Set (BSS) identification information, Wherein the frame is a request to send (RTS) frame or a clear to send (CTS) frame.

The BSS identification information may be included in the service field of the frame.

The BSS identification information may include a BSS color identifier.

The BSS identification information may include an indicator indicating a mode using the BSS identification information.

The frame includes a service field, the first 7 bits of the service field corresponding to the first 7 bits of the scrambling sequence, and a bit of the first 7 bits of the scrambling sequence may include the BSS identification information.

The fourth through seventh bits of the first 7 bits of the scrambling sequence may include the BSS identification information.

The fourth bit of the first 7 bits of the scrambling sequence may include an indication of transmission of the BSS identification information and the fifth to seventh bits of the first 7 bits of the scrambling sequence may include a BSS color identifier.

The fifth through seventh bits of the first 7 bits of the scrambling sequence may include the BSS identification information.

The fifth bit of the first 7 bits of the scrambling sequence may include an indication of transmission of the BSS identification information and the 6th to 7th bits of the first 7 bits of the scrambling sequence may include a BSS color identifier.

The third through seventh bits of the first 7 bits of the scrambling sequence may include the BSS identification information.

A predetermined bit among the first 7 bits of the scrambling sequence may include a first value corresponding to an indicator indicating transmission of BSS identification information and a second value corresponding to an indicator indicating a bandwidth used.

The frame includes a frame control field, and a predetermined bit of the frame control field may include information informing a Medium Access Control (MAC) layer of the use of the BSS identification information.

The frame includes a service field, and at least some bits from the eighth through sixteenth bits of the service field may include information indicating the use of the BSS identification information in a Medium Access Control (MAC) layer.

A method of receiving a frame of a device in a wireless local area network (WLAN) according to another embodiment of the present invention includes receiving a frame and obtaining a Basic Service Set (BSS) identification information included in the frame Wherein the frame is a request to send (RTS) frame or a clear to send (CTS) frame.

The service field of the frame may include the BSS identification information.

The first 7 bits of the service field correspond to the first 7 bits of the scrambling sequence and a predetermined bit of the first 7 bits of the scrambling sequence may indicate the BSS identification information.

The step of acquiring the BSS identification information may select a bit to which the BSS identification information is transmitted from among the first 7 bits of the scrambling sequence and obtain the BSS identification information by mapping the value of the selected bit to a designated parameter.

The frame receiving method may further include determining whether to transmit frames simultaneously based on the BSS identification information.

The step of determining whether or not to transmit the frame simultaneously may determine that at least some of the period information corresponding to the period field of the frame is a simultaneous frame transmission period when the BSS identification information of the frame is different from the BSS identification information of the frame .

The determining whether or not to simultaneously transmit the frame may determine whether the frame is simultaneously transmitted based on the interference level with the device that transmitted the frame, when the BSS identification information of the frame is different from the BSS identification information of the frame.

According to an exemplary embodiment of the present invention, the wireless LAN device identifies RTS / CTS frames transmitted from other BSSs and simultaneously transmits the RTS / CTS frames occupied by the RTS / CTS frames. That is, according to one embodiment of the present invention, the wireless LAN device can identify the BSS of the RTS / CTS frame and increase the transmission opportunity. According to an embodiment of the present invention, it is possible to increase the reception probability of a packet transmitted from the same BSS and reduce unnecessary signaling processing of a packet transmitted from another BSS, thereby improving system efficiency.

According to an embodiment of the present invention, BSS information is transmitted using some bits of the service field, so that resources of a limited signal field can be saved.

According to an embodiment of the present invention, the wireless LAN device can indicate an operation mode of at least one of a dynamic bandwidth allocation mode and a BSS color mode.

1 is a schematic block diagram illustrating the structure of a wireless LAN device.
2 is a schematic block diagram illustrating a transmission signal processing unit in a wireless LAN.
3 is a schematic block diagram illustrating a received signal processing unit in a wireless LAN.
4 is a diagram showing an interframe space (IFS) relationship.
5 is a conceptual diagram for explaining a frame transmission procedure according to a carrier sense multiple access (CSMA) / collision avoidance (CA) scheme for avoiding collision between frames in a channel.
6 is a diagram illustrating an RTS frame structure in a wireless LAN.
7 is a diagram illustrating a CTS frame structure in a wireless LAN.
8 is a diagram illustrating a high efficiency WLAN (HEW) frame structure.
9 and 10 are views illustrating downlink transmission in a wireless LAN.
11 to 13 are views illustrating uplink transmission in a wireless LAN.
14 and 15 are diagrams illustrating downlink transmission in a wireless LAN.
16 is a diagram illustrating a service field of a frame according to an embodiment of the present invention.
17 is a diagram exemplarily showing a scrambler generator.
18 is a diagram illustrating a frame control field structure in a wireless LAN.
19 to 22 each illustrate exemplary simultaneous transmission in a wireless LAN according to an embodiment of the present invention.
23 and 24 are diagrams for explaining a BSS identification information-based frame processing method according to an embodiment of the present invention.
25 to 26 are flowcharts of a BSS identification information based frame processing method according to another embodiment of the present invention.
27 is a flowchart of a BSS identification information based frame processing method according to another embodiment of the present invention.
28 is a view for explaining a BSS identification information based frame processing method according to another embodiment of the present invention.
29 is a flowchart of a method of transmitting BSS identification information in a wireless LAN according to an embodiment of the present invention.
30 is a flowchart of a method for simultaneously transmitting frames in a wireless LAN according to an embodiment of the present invention.
31 and 32 each illustrate a signal field including BSS information in a frame according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

A basic service set (BSS) in a wireless local area network (WLAN) (hereinafter referred to as a "wireless LAN") includes a plurality of wireless LAN devices. The WLAN device may include a medium access control (MAC) layer and a physical (PHY) layer according to the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard. At least one of the plurality of wireless LAN devices may be an access point (AP), and the remaining wireless LAN device may be a non-AP station (non-AP STA). Or ad-hoc networking, a plurality of wireless LAN devices may all be non-AP stations. In general, a station (STA) is also used when collectively referred to as an access point (AP) and a non-AP station, but for simplicity, the non-AP station is also abbreviated as a station (STA).

1 is a schematic block diagram illustrating the structure of a wireless LAN device.

1, the wireless LAN device 1 includes a baseband processor 10, a radio frequency (RF) transceiver 20, an antenna unit 30, a memory 40, an input interface unit 50, An output interface unit 60 and a bus 70. Fig.

The baseband processor 10 performs the baseband-related signal processing described herein, and includes a MAC processor 11, a PHY processor 15, and the like.

In one embodiment, the MAC processor 11 may include a MAC software processing unit 12 and a MAC hardware processing unit 13. At this time, the memory 40 includes software (hereinafter referred to as "MAC software") including some functions of the MAC layer, and the MAC software processing unit 12 implements some functions of the MAC by driving the MAC software, The MAC hardware processing unit 13 may implement the remaining functions of the MAC layer as hardware (hereinafter referred to as "MAC hardware"), but is not limited thereto.

The PHY processor 15 includes a transmission signal processing unit 100 and a reception signal processing unit 200.

The baseband processor 10, the memory 40, the input interface unit 50 and the output interface unit 60 can communicate with each other via the bus 70. [

The RF transceiver 20 includes an RF transmitter 21 and an RF receiver 22.

In addition to the MAC software, the memory 40 may store an operating system, an application, etc., and the input interface unit 50 acquires information from the user, and the output interface unit 60 acquires information from the user Output.

The antenna section 30 includes one or more antennas. When using multiple-input multiple-output (MIMO) or multi-user MIMO (MU-MIMO), the antenna unit 30 may include a plurality of antennas.

2 is a schematic block diagram illustrating a transmission signal processing unit in a wireless LAN.

2, the transmission signal processing unit 100 includes an encoder 110, an interleaver 120, a mapper 130, an inverse Fourier transformer 140, and a guard interval (GI) inserter 150 do.

Encoder 110 encodes the input data and may be, for example, a forward error correction (FEC) encoder. The FEC encoder may include a binary convolutional code (BCC) encoder, in which case a puncturing device may be included. Or the FEC encoder may include a low-density parity-check (LDPC) encoder.

The transmission signal processing unit 100 may further include a scrambler scrambling the input data before encoding the input data to reduce the probability that a long same sequence of 0's or 1's occurs. If a plurality of BCC encoders are used as the encoder 110, the transmission signal processing unit 100 may further include an encoder parser for demultiplexing the scrambled bits into a plurality of BCC encoders. When an LDPC encoder is used as the encoder 110, the transmission signal processing unit 100 may not use the encoder parser.

The interleaver 120 interleaves the bits of the stream output from the encoder 110 to change the order. Interleaving may be applied only when a BCC encoder is used as the encoder 110. [ The mapper 130 maps the bit stream output from the interleaver 120 to constellation points. When an LDPC encoder is used as the encoder 110, the mapper 130 may perform LDPC tone mapping in addition to the property store mapping.

When MIMO or MU-MIMO is used, the transmission signal processing unit 100 may use a plurality of interleavers 120 and a plurality of mappers 130 corresponding to the number of spatial streams N _SS . The transmission signal processing unit 100 may further include a stream parser that divides outputs of a plurality of BCC encoders or LDPC encoders into a plurality of blocks to be provided to different interleavers 120 or a mapper 130. The transmission signal processing unit 100 further includes a space-time block code (STBC) encoder and a space-time block code (STBC) encoder for spreading a property point from N _SS spatial streams to N _STS space- transmit chains. < / RTI > The spatial mapper can use direct mapping, spatial expansion, beamforming, or the like.

The inverse Fourier transformer 140 transforms a sex store block output from the mapper 130 or the spatial mapper into an inverse discrete Fourier transform (IDFT) or an inverse fast Fourier transform (IFFT) Domain block, that is, a symbol. When the STBC encoder and the spatial mapper are used, the inverse Fourier transformer 140 may be provided for each transmission chain.

When MIMO or MU-MIMO is used, the transmission signal processing unit may insert cyclic shift diversity (CSD) before or after inverse Fourier transform to prevent unintentional beamforming. The CSD may be specified for each transport chain or for each space-time stream. Or CSD may be applied as part of a spatial mapper.

Also, when using MU-MIMO, some blocks before the space mapper may be provided for each user.

The GI inserter 150 inserts a GI in front of the symbol. The transmission signal processing unit 100 can smoothly window the edge of the symbol after inserting the GI. The RF transmitter 21 converts the symbol into an RF signal and transmits it via the antenna. When MIMO or MU-MIMO is used, the GI inserter 150 and the RF transmitter 21 can be provided for each transmission chain.

3 is a schematic block diagram illustrating a received signal processing unit in a wireless LAN.

3, the received signal processing unit 200 includes a GI eliminator 220, a Fourier transformer 230, a demapper 240, a deinterleaver 250, and a decoder 260.

The RF receiver 22 receives the RF signal through the antenna and converts it into a symbol, and the GI remover 220 removes the GI from the symbol. When using MIMO or MU-MIMO, the RF receiver 22 and the GI remover 220 may be provided for each receive chain.

The Fourier transformer 230 transforms symbols, i.e., time domain blocks, into discrete Fourier transforms (DFTs) or fast Fourier transforms (FFTs) into frequency domain ghost points. Fourier transformer 230 may be provided for each receive chain.

If MIMO or MU-MIMO is used, it may include a spatial demapper that transforms the Fourier transformed reception chain into a spatiotemporal stream, and an STBC decoder that despreads the span stream from the space-time stream to the spatial stream. have.

The dem mapper 240 demaps the block of the sex store output from the Fourier transformer 230 or the STBC decoder into a bit stream. If the received signal is LDPC encoded, demapper 240 may perform further LDPC tone demapping before property demapping. The deinterleaver 250 deinterleaves the bits of the stream output from the demapper 240. Deinterleaving can be applied only when the received signal is BCC encoded.

In case of using MIMO or MU-MIMO, the received signal processing unit 200 may use a plurality of demapper 240 and a plurality of deinterleavers 250 corresponding to the number of spatial streams. At this time, the received signal processing unit 200 may further include a stream deparser that combines the streams output from the plurality of deinterleavers 250.

The decoder 260 decodes the stream output from the deinterleaver 250 or the stream decoder, and may be, for example, an FEC decoder. The FEC decoder may include a BCC decoder or an LDPC decoder. The received signal processing unit 200 may further include a descrambler for descrambling the decoded data by the decoder 260. When a plurality of BCC decoders are used as the decoder 260, the received signal processing unit 200 may further include an encoder deparser for multiplexing the decoded data. When the LDPC decoder is used as the decoder 260, the received signal processing unit 200 may not use the encoder de-parser.

4 is a diagram showing an interframe space (IFS) relationship.

A data frame, a control frame, and a management frame may be exchanged between the wireless LAN devices.

A data frame is a frame used for transmission of data forwarded to an upper layer. The data frame is transmitted after performing a backoff after the DIFS (Distributed Coordination Function IFS) from when the medium becomes idle. The management frame is used for exchange of management information that is not forwarded to the upper layer, and is transmitted after backoff after IFS such as DIFS or PIFS (point coordination function IFS). The subtype frame of the management frame includes Beacon, Association request / response, probe request / response, and authentication request / response. A control frame is a frame used for controlling access to a medium. Subtype frames of the control frame include RTS, CTS, and ACK. The control frame is transmitted after backoff after DIFS elapses when it is not a response frame of another frame, and is transmitted without backoff after SIFS (short IFS) if it is a response frame of another frame. The type and subtype of the frame can be identified by the type field and the subtype field in the frame control field.

Meanwhile, the QoS (Quality of Service) STA can transmit an arbitration IFS (AIFS) for an access category (AC) to which a frame belongs, i.e., a frame after the backoff after the AIFS [AC] elapses. At this time, a frame in which AIFS [AC] can be used may be a control frame, not a data frame, a management frame, and a response frame.

5 is a conceptual diagram for explaining a frame transmission procedure according to a carrier sense multiple access (CSMA) / collision avoidance (CA) scheme for avoiding collision between frames in a channel.

Referring to FIG. 5, a first device STA1 denotes a transmitting device to which data is to be transmitted, and a second device STA2 denotes a receiving device that receives data transmitted from the first device STA1. The third device STA3 may be located in an area capable of receiving a frame transmitted from the first device STA1 and / or a frame transmitted from the second device STA2.

The first device STA1 can determine whether a channel is being used through carrier sensing. The first device STA1 may determine the occupancy state of the channel based on the magnitude of the energy existing in the channel or the correlation of the signal or may use a network allocation vector (NAV) The occupied state can be judged.

When the first device STA1 determines that the channel is not used by another device during DIFS (i.e., when the channel is idle), the first device STA1 transmits a request to send (RTS) (STA2). When receiving the RTS frame, the second device STA2 may transmit a clear to send (CTS) frame, which is a response to the RTS frame, to the first device STA1 after SIFS.

On the other hand, when receiving the RTS frame, the third device STA3 transmits the frame transmission period (for example, SIFS + CTS frame + SIFS + data) continuously transmitted subsequently using the duration information included in the RTS frame Frame + SIFS + ACK frame). Alternatively, when receiving the CTS frame, the third device STA3 may use the period information included in the CTS frame to transmit a frame transmission period (for example, SIFS + data frame + SIFS + ACK frame) You can set the NAV timer for. The third device STA3 may update the NAV timer using the period information included in the new frame if the new device has received a new frame before expiration of the NAV timer. The third device STA3 does not attempt to access the channel until the NAV timer expires.

When receiving the CTS frame from the second device STA2, the first device STA1 may transmit the data frame to the second device STA2 after SIFS from the completion of reception of the CTS frame. When the second device STA2 successfully receives the data frame, the second device STA2 may transmit an ACK frame, which is a response to the data frame, to the first device STA1 after SIFS.

The third device STA3 can determine whether the channel is being used through carrier sensing when the NAV timer expires. The third device STA3 may attempt to access the channel after the contention window CW due to the random backoff has passed when the channel is determined not to be used by another device during the DIFS since the expiration of the NAV timer.

FIG. 6 is a diagram illustrating an RTS frame structure in a wireless LAN, and FIG. 7 is a diagram illustrating a CTS frame structure in a wireless LAN. The frame structure in Figs. 6 and 7 is a PHY frame.

6, an RTS frame includes a legacy short training field L-STF, a legacy long training field L-LTF, a legacy signal field L-SIG, a service field, and a tail field. Here, the data field of the PHY frame may include a service field, a MAC frame part, and a tail field.

Legacy Short Training Field (L-STF), Legacy Long Training Field (L-LTF), and Legacy Signal Field (L-SIG) are legacy signal parts that provide signaling information to maintain compatibility with previous versions of the WLAN device. Carry. The legacy short training field (L-STF) and the legacy long training field (L-LTF) can be used for synchronization and channel estimation. The legacy signal field (L-SIG) may include rate and length information.

The service field corresponds to the first 16 bits of the PHY data field. The first 7 bits of the service field are scrambler initialization bits and the remaining 9 bits are reserved bits.

The MAC frame part of the RTS frame includes a frame control field, a duration field, a receive address (RA) field, a transmit address (TA) field, and a frame check sequence (FCS) field.

The frame control field includes a type field, a subtype field, and the like. The duration field includes transmission period information of frames continuously transmitted after the RTS frame. The RA field contains the address of the intended recipient. The TA field contains the address of the device transmitting the RTS frame. The FCS field includes, for example, a 32-bit CRC.

7, the CTS frame includes a legacy short training field (L-STF), a legacy long training field (L-LTF), a legacy signal field (L-SIG), a service field, a MAC frame part and a tail field .

The MAC frame part of the CTS frame includes a frame control field, a period field, an RA field, and an FCS field. The period field includes transmission period information of frames continuously transmitted after the CTS frame. The RA field is copied from the TA field of the RTS frame.

8 is a diagram illustrating a high efficiency WLAN (HEW) frame structure.

Referring to FIG. 8, the HEW frame includes a legacy signal part and a HEW part.

The legacy signal part carries the signaling information to maintain compatibility with the previous version of the wireless LAN device. The legacy signal part includes a legacy short training field (L-STF), a legacy long training field (L-LTF) and a legacy signal field -SIG).

The HEW part is a part transmitted from the HEW device, for example, a HEW signal field (HEW-SIG-A), a HEW short training field (HEW-STF), a HEW long training field (HEW-SIG-B), a service field, a HEW data field, and a tail field. The HEW data field may comprise a combined MPDU (Aggregate Mac Protocol Data Unit, A-MPDU). Here, the signal field includes signaling information for communication between HEW devices.

The legacy preamble included in the legacy compatible part can be transmitted in common for all bands. In addition, the HEW signal field (HEW-SIG-A) included in the legacy compatible part can also be duplicated in each band.

FIGS. 9 and 10 illustrate downlink transmission in a wireless LAN, FIGS. 11 to 13 illustrate uplink transmission in a wireless LAN, and FIGS. 14 and 15 illustrate downlink transmission in a wireless LAN. Lt; RTI ID = 0.0 > transmission.

Referring to FIG. 9 and FIG. 10, a plurality of BSSs are overlapped in the wireless communication network. In this case, when AP1 transmits downlink data to STA1, a case where neighboring devices STA2 and STA3 of AP1 and STA1 receive either RTS frame or CTS frame will be described as an example. It is assumed that STA1 belongs to BSS1 related to AP1, STA2 belongs to BSS2 related to AP2, and STA3 belongs to BSS3 related to AP3.

If AP1 has downlink data to be sent to STA1, it transmits an RTS frame. At this time, the RA field of the RTS frame is set to the address of STA1, and the TA field is set to the address of AP1. The STA1 receiving the RTS frame transmits a CTS frame because its address value matches the value of the RA field of the RTS frame. At this time, the TA field of the RTS frame is copied to the RA field of the CTS frame. The AP1 receiving the CTS frame transmits the data frame after the SIFS elapses, and the STA1 receiving the data frame transmits the ACK frame after the elapse of the SIFS.

Meanwhile, the STA2 located in the RTS frame protection area receives the RTS frame. Since the address value of the STA2 is different from the value of the RA field of the RTS frame, the STA2 sets the NAV based on the period field of the RTS frame.

The STA3 located in the CTS frame protection area receives the CTS frame. Since the address value of the STA3 is different from the value of the RA field of the CTS frame, the STA3 sets the NAV based on the duration field of the CTS frame.

Thus, STA2 and STA3 lose the transmission opportunity by setting the NAV for the RTS / CTS frame transmitted from the overlapped BSS (OBSS).

Referring to FIG. 11 and FIG. 12, when STA1 transmits uplink data to AP1, neighboring devices STA2 and STA3 of AP1 and STA1 receive either RTS frame or CTS frame.

When STA1 has uplink data to be transmitted to AP1, it transmits an RTS frame. At this time, the RA field of the RTS frame is set to the address of AP1, and the TA field is set to the address of STA1. The AP1 receiving the RTS frame transmits a CTS frame because its address value matches the value of the RA field of the RTS frame. The STA1 receiving the CTS frame transmits the data frame after the SIFS elapses and the AP1 receiving the data frame transmits the ACK frame after the elapse of the SIFS.

On the other hand, the STA3 located in the RTS frame protection area receives the RTS frame. Since the address value of the STA3 is different from the value of the RA field of the RTS frame, the STA3 sets the NAV based on the period field of the RTS frame.

The STA2 located in the CTS frame protection area receives the CTS frame. Since the address value of the STA2 is different from the value of the RA field of the CTS frame, the STA2 sets the NAV based on the duration field of the CTS frame.

Referring to FIG. 11 and FIG. 13, when STA1 has uplink data to be transmitted to AP1, it transmits an RTS frame. However, STA2 can also transmit an RTS frame when there is uplink data to be transmitted to AP1.

If STA1 and STA2 transmit RTS frames with a very short time difference, two frames may collide. Then, the STA1 retransmits the RTS frame after the random backoff, and the AP1 receiving the RTS frame can transmit the CTS frame. The STA1 receiving the CTS frame transmits the data frame after the SIFS elapses and the AP1 receiving the data frame transmits the ACK frame after the elapse of the SIFS.

Meanwhile, the STA3 located in the RTS frame protection area receives the RTS frame transmitted by the STA1. Since the address value of the STA3 is different from the value of the RA field of the RTS frame, the STA3 sets the NAV based on the period field of the RTS frame.

The STA2 located in the CTS frame protection area receives the CTS frame transmitted by the AP1. Since the address value of the STA2 is different from the value of the RA field of the CTS frame, the STA2 sets the NAV based on the duration field of the CTS frame.

Thus, STA2 and STA3 lose the transmission opportunity by setting the NAV for the RTS / CTS frame transmitted in the OBSS.

Referring to FIG. 14 and FIG. 15, the STA 4 of the BSS 4 can receive both the RTS frame and the CTS frame transmitted from the BSS 1. The STA4 receiving the RTS frame transmitted by the AP1 sets the NAV based on the duration field of the RTS frame since its own address value is different from the RA field of the RTS frame. The STA 4 that has received the CTS frame transmitted by the STA 1 updates the NAV based on the duration field of the CTS frame because its address value is different from the RA field of the CTS frame.

Therefore, the STA4 loses the transmission opportunity by setting the NAV for the RTS / CTS frame transmitted in the OBSS.

As described above with reference to FIG. 9 to FIG. 15, the wireless LAN device sets an unnecessary NAV by the frame transmitted from the OBSS. Therefore, there is a problem that the wireless LAN device loses its transmission opportunity and consequently the yield is lowered.

If the wireless LAN device is able to identify the BSS of the received frame, it is not necessary to set the NAV for the RTS / CTS frame transmitted from the OBSS, even if it is not the destination, Lt; / RTI > In addition, if the wireless LAN device can identify the BSS of the received frame, the CCA (Clear Channel Assessment) level and the receiver sensitivity are set low for the frame transmitted from its BSS, and the frame transmitted from the other BSS The CCA level and the reception sensitivity can be set high.

Hereinafter, a BSS information transmission and identification method according to an embodiment of the present invention will be described in detail. The wireless communication network according to an embodiment of the present invention may be various wireless LANs, but it can be explained on the assumption of a high efficiency wireless LAN (HEW) developed in the IEEE 802.11ax task group.

The BSS information is information that can identify the BSS and can be expressed in various forms. For example, the BSS information may include identification information such as a BSS ID, a BSS color ID, a BSS color indication, a partial association ID (PAID) have. In the following, a method of identifying the BSS using the BSS color is mainly described, but the BSS identification information is not limited to the BSS color.

According to an embodiment of the present invention, the transmission frame includes an indicator for instructing use of BSS identification information, and the indicator may be a BSS color indicator. The BSS color indicator is an indicator indicating the use of the BSS color, indicating whether the frame is a BSS color mode for transmitting a BSS color identifier. When the BSS color indicator indicates use of the BSS color, the WLAN device recognizes the operation mode as a BSS color mode and extracts the BSS color identifier from the received frame.

According to one embodiment, the BSS identification information may be transmitted using some bits of the service field of the transmission frame. According to another embodiment, the BSS identification information may be transmitted using some bits of the signal field of the transmission frame. Here, the BSS identification information may include at least one of a BSS color indicator and a BSS color indicator. The transmission frame may be an RTS / CTS frame, and the RTS / CTS frame may convey BSS identification information before data frame transmission.

First, a method of transmitting BSS identification information using some bits among the first 7 bits of the service field will be described.

FIG. 16 is a diagram showing a service field of a frame according to an embodiment of the present invention, and FIG. 17 is a diagram exemplarily showing a scrambler generator.

Referring to FIG. 16, the service field 300 corresponds to the first 16 bits of the data field of the PHY frame. The first 7 bits (B0-B6) of the service field 300 are the scrambler initialization bits and the remaining 9 bits (B7-B15) are reserved bits. The scrambler initialization bit is used for synchronization with a descrambler and is set to be able to estimate the initial state of the scrambler at the receiving device.

The data field of the PHY frame is scrambled with a 127-bit long frame synchronization scrambler. A 127 bit scrambling sequence is repeatedly generated by the scrambler. The 127-bit sequence is determined by a 7-bit scrambler seed used to initialize the scrambler and a 7-th generator polynomial of the scrambler. The first 7 bits of the 127-bit sequence are the same as the scrambler seed. The scrambler seed is determined by the TXVECTOR or RXVECTOR parameters. TXVECTOR is a list of parameters to provide to the local sublayer of the PHY entity in the MAC sublayer, and RXVECTOR is a list of parameters to be provided by the PHY to the local MAC entity.

When transmitting a frame in a WLAN device, if the TXVECTOR parameter CH_BANDWIDTH_IN_NON_HT does not exist, the initial state of the scrambler is set to a pseudo-random non-zero state. If the TXVECTOR parameter CH_BANDWIDTH_IN_NON_HT is present, the first seven bits of the scrambling sequence are set to the values specified in Table 1 or Table 9 and used to initialize the state of the scrambler. The remaining bits of the scrambling sequence may be generated by the scrambling generator shown in Fig.

The transmitting device and the receiving device use the same scrambler. Since the first 7 bits of the scrambler seed and the scrambling sequence are mapped on a one to one basis and the scrambler initialization bit is set to "0000000 ", the first 7 bits of the data field scrambled and output as the scrambling sequence of the data field before scrambling are output to the beginning of the scrambling sequence 7 bits. Thus, the receiving device may determine the first 7 bits of the data field in the received frame as a scrambler seed, and use the scrambler seed to generate the same scrambling sequence as the transmitting device. Whereby the receiving device can descramble the data field.

BSS identification information according to an embodiment of the present invention includes 3 bits (bits 4 (B4) to 6 (B6)), 4 bits (bits 3 (B3) to 6 (B6)) of the first 7 bits of the scrambling sequence, ) Or five bits (bit 2 (B2) to bit 6 (B6)). The first 7 bits of the scrambling sequence are the same as the first 7 bits of the scrambled data field, i.e., the first 7 bits of the service field.

First, referring to Table 1 to Table 8, an embodiment will be described in which four bits (bits 3 (B3) to 6 (B6)) out of the first 7 bits of the service field are used as BSS identification information. Here, if the BSS_COLOR_IN_NON_HT parameter is present in the TXVECTOR, the fourth bit (B3) of the scrambler initialization bit is used as the BSS color indicator. If the BSS color indicator is "1 ", it operates in the BSS color mode and the remaining three bits indicate the BSS color identifier. When the BSS color indicator is "0 ", it operates in dynamic bandwidth allocation mode.

Table 1 shows the first seven bits of the scrambling sequence according to the TXVECTOR and RXVECTOR parameters in a wireless communication network according to one embodiment of the present invention.

parameter Condition The first 7 bits of the scrambling sequence B0-B2 B3 B4 B5-B6 TXVECTOR CH_BANDWIDTH_IN_NON_HT exists, DYN_BANDWIDTH_IN_NON_HT does not exist in TXVECTOR,
BSS_COLOR_IN_NON_HT does not exist in TXVECTOR If CH_BANDWIDTH_IN_NON_HT is equal to CBW20, it is a 5 bit pseudorandom nonzero integer,
Otherwise, a 5-bit pseudorandom integer CH_BANDWIDTH_IN_NON_HT TXVECTOR CH_BANDWIDTH_IN_NON_HT exists, DYN_BANDWIDTH_IN_NON_HT exists in TXVECTOR,
BSS_COLOR_IN_NON_HT does not exist in TXVECTOR If CH_BANDWIDTH_IN_NON_HT is equal to CBW20 and DYN_BANDWIDTH_IN_NON_HT is equal to static, it is a 4-bit pseudorandom nonzero integer,
Otherwise, a 4-bit pseudorandom integer DYN_BANDWIDTH_IN_NON_HT
RXVECTOR CH_BANDWIDTH_IN_NON_HT and DYN_BANDWIDTH_IN_NON_HT are present in RXVECTOR,
BSS_COLOR_IN_NON_HT does not exist in RXVECTOR - DYN_BANDWIDTH_IN_NON_HT Mapping to CH_BANDWIDTH_IN_NON_HT according to Table 3 TXVECTOR BSS_ID_CH_BW_IN_NON_HT is present in TXVECTOR,
DYN_BANDWIDTH_IN_NON_HT exists in TXVECTOR, BSS_COLOR_IN_NON_HT exists in TXVECTOR If CH_BANDWIDTH_IN_NON_HT is equal to CBW20 and BSS_COLOR_IN_NON_HT is equal to no color, it is a 3 bit pseudorandom nonzero integer,
Otherwise, a 3-bit pseudorandom integer BSS_COLOR_IN_NON_HT (= 0) DYN_BANDWIDTH_IN_NON_HT BSS_ID_CH_BW_IN_NON_HT (= CH_BANDWIDTH_IN_NON_HT) RXVECTOR BSS_ID_CH_BW_IN_NON_HT is present in RXVECTOR,
DYN_BANDWIDTH_IN_NON_HT exists in RXVECTOR, BSS_COLOR_IN_NON_HT exists in RXVECTOR - BSS_COLOR_IN_NON_HT (= 0) DYN_BANDWIDTH_IN_NON_HT Mapping to BSS_ID_CH_BW_IN_NON_HT (= CH_BANDWIDTH_IN_NON_HT) according to Table 3 TXVECTOR BSS_ID_CH_BW_IN_NON_HT is present in TXVECTOR,
DYN_BANDWIDTH_IN_NON_HT exists in TXVECTOR, BSS_COLOR_IN_NON_HT exists in TXVECTOR If CH_BANDWIDTH_IN_NON_HT is equal to CBW20 and BSS_COLOR_IN_NON_HT is equal to no color, it is a 3 bit pseudorandom nonzero integer,
Otherwise, a 3-bit pseudorandom integer BSS_COLOR_IN_NON_HT (= 1) BSS_ID_CH_BW_IN_NON_HT RXVECTOR BSS_ID_CH_BW_IN_NON_HT is present in RXVECTOR,
DYN_BANDWIDTH_IN_NON_HT exists in RXVECTOR, BSS_COLOR_IN_NON_HT exists in RXVECTOR - BSS_COLOR_IN_NON_HT (= 1) Mapping to BSS_ID_CH_BW_IN_NON_HT according to Table 7

Table 2 shows the CH_BANDWIDTH_IN_NON_HT parameter among the TXVECTOR parameters used in Table 1. The CH_BANDWIDTH_IN_NON_HT parameter indicates either CBW20, CBW40, CBW80, CBW160 or CBW80 + 80.

Enumerated value meaning value CBW20 Channel Bandwidth 20 MHz 0 CBW40 Channel bandwidth 40 MHz One CBW80 Channel Bandwidth 80 MHz 2 CBW160 or
CBW80 + 80 Channel bandwidth 160 MHz or channel bandwidth 80 MHz + 80 MHz 3

Table 3 shows the CH_BANDWIDTH_IN_NON_HT parameter among the RXVECTOR parameters used in Table 1.

CbwInNonHtTemp Dot11CurrentChannelCenterFrequencyIndex RXVECTOR parameter 0 0 CBW20 One 0 CBW40 2 0 CBW80 3 0 CBW160 3 1 to 200 CBW80 + 80

Table 4 shows the DYN_BANDWIDTH_IN_NON_HT parameters used in Table 1. The DYN_BANDWIDTH_IN_NON_HT parameter indicates either "static" or "dynamic". If the value is "0 ", indicating that the dynamic bandwidth allocation mode is not supported, and if the value is" 1 "

Enumerated value value Static 0 Dynamic One

Table 5 and Table 6 show the BSS_ID_CH_BW_IN_NON_HT parameter among the TXVECTOR parameters used in Table 1. The BSS_ID_CH_BW_IN_NON_HT parameter may be the sixth bit and the seventh bit [B5: B6], or the fifth bit to the seventh bit [B4: B6].

If BSS_COLOR_IN_NON_HT (B3) is "0", the DYN_BANDWIDTH_IN_NON_HT parameter may be set in the fifth bit (B4). In this case, the BSS_ID_CH_BW_IN_NON_HT parameter is set in the sixth bit and the seventh bit, and the value of BSS_ID_CH_BW_IN_NON_HT can be defined according to DYN_BANDWIDTH_IN_NON_HT (B4) as shown in Table 5. [

BSS_COLOR_IN_NON_HT (B3) DYN_BANDWIDTH_IN_NON_HT (B4) Enumerated value meaning value
[B5: B6] 0 One CBW20 Channel Bandwidth 20 MHz 0 0 One CBW40 Channel bandwidth 40 MHz One 0 One CBW80 Channel Bandwidth 80 MHz 2 0 One CBW160 or
CBW80 + 80 Channel bandwidth 160 MHz or channel bandwidth 80 MHz + 80 MHz 3

When BSS_COLOR_IN_NON_HT (B3) is "1", the BSS_ID_CH_BW_IN_NON_HT parameter is assigned to the seventh bit from the fifth bit, and the value of BSS_ID_CH_BW_IN_NON_HT can be defined as shown in Table 6. The value of BSS_ID_CH_BW_IN_NON_HT may mean a BSS color identifier.

BSS_COLOR_IN_NON_HT (B3) Enumerated value meaning BSS_ID_CH_BW_IN_NON_HT
[B4: B6] One BCID0 BSS Color ID 0 0 One BCID1 BSS Color ID 1 One One BCID2 BSS Color ID 2 2 One BCID3 BSS Color ID 3 3 One BCID4 BSS Color ID 4 4 One BCID5 BSS Color ID 5 5 One BCID6 BSS Color ID 6 6 One BCID7 BSS Color ID 7 7

Table 7 shows the BSS_ID_CH_BW_IN_NON_HT parameter when the BSS_COLOR_IN_NON_HT is "1" among the RXVECTOR parameters used in Table 1. On the other hand, among the RXVECTOR parameters used in Table 1, the BSS_ID_CH_BW_IN_NON_HT parameter when BSS_COLOR_IN_NON_HT is "0" can be mapped according to Table 3. [

BssColorIdNonHtTemp RXVECTOR parameter 0 BSS Color ID 0 One BSS Color ID 1 2 BSS Color ID 2 3 BSS Color ID 3 4 BSS Color ID 4 5 BSS Color ID 5 6 BSS Color ID 6 7 BSS Color ID 7

Table 8 shows the BSS_COLOR_IN_NON_HT parameters used in Table 1.

Enumerated value value Not support BSS Color 0 Support BSS Color One

Referring to Table 1, CH_BANDWIDTH_IN_NOT_HT, DYN_BANDWIDTH_IN_NON_HT, BSS_COLOR_IN_NON_HT, BSS_ID_CH_BW_IN_NON_HT, and the like exist as TXVECTOR parameter and RXVECTOR parameter. In Table 1, the CH_BANDWIDTH_IN_NOT_HT parameter is defined as shown in Table 2 and Table 3, and the DYN_BANDWIDTH_IN_NON_HT parameter is defined as shown in Table 4. In Table 1, BSS_COLOR_IN_NON_HT and BSS_ID_CH_BW_IN_NON_HT are the BSS parameters defined in the wireless communication network, in particular in the HEW, according to an embodiment of the present invention.

Referring to Table 1, the operation mode of the wireless LAN device is selected by using 2 bits (B3, B4) out of the first 7 bits of the scrambling sequence.

If the fourth bit B3 is "0 ", the wireless LAN device operates in the dynamic bandwidth allocation mode according to the DYN_BANDWIDTH_IN_NON_HT parameter B4. The fifth bit B4 indicates the DYN_BANDWIDTH_IN_NON_HT parameter (static, dynamic) as shown in Table 4. The sixth bit and the seventh bit B5 and B6 are used for indicating the channel bandwidth as shown in Table 5. [

If the fourth bit B3 is "1 ", the wireless LAN device operates in the BSS color mode. In the BSS color mode, the fifth bit to the seventh bit (B4, B5, B6) are used for indicating the BSS color identifier as shown in Table 6.

If the VHT device is the receiver of data, the fourth bit (B3) of the first 7 bits of the scrambling sequence can be set to "0" and used for dynamic bandwidth allocation. If the HEW device is a data receiver, the fourth bit (B3) of the first 7 bits of the scrambling sequence may be set to "1" and the remaining three bits may be used as the BSS color identifier.

Referring to Tables 5 and 6 and Table 8, the BSS_COLOR_IN_NON_HT parameter is set to the fourth bit (B3) of the scrambler initialization bits. The BSS_COLOR_IN_NON_HT parameter is a BSS color indicator indicating the BSS color mode.

If BSS_COLOR_IN_NON_HT is "0" and DYN_BW_IN_NON_HT is "1", the fifth bit and the sixth bit (B5, B6) of the scrambler initialization bits do not support the BSS color do.

If BSS_COLOR_IN_NON_HT is "1", support BSS color (support BSS color). The BSS_ID_CH_BW_IN_NON_HT parameter indicating the BSS color identifier is set for the fourth bit to the sixth bit (B4, B5, B6) of the scrambler initialization bits.

Referring to Table 7, the BssColorIdInNonHtTemp value is mapped to one of the BSS Color ID 0 to the BSS Color ID 7 of the RXVECTOR parameter BSS_COLOR_ID_IN_NON_HT parameter.

The first through third rows of Table 1 provide backward compatibility for previous versions of a wireless communication network, e.g., a VHT device, in a wireless communication network according to an embodiment of the present invention. If the CH_BANDWIDTH_IN_NON_HT parameter is present in the TXVECTOR parameter and the DYN_BANDWIDTH_IN_NON_HT parameter is not present, the transmitting VHT device sets the first 7 bits of the scrambling sequence as the first row of Table 1. The last two bits (B5, B6) of 7 bits are set according to the value of the CH_BANDWIDTH_IN_NON_HT parameter. At this time, the value of the CH_BANDWIDTH_IN_NON_HT parameter may be transmitted in LSB (Least Significant Bit) first. For example, since the value of CBW80 is "2" and the binary value is "10", B5 is set to "0" and B6 is set to "1". If the CH_BANDWIDTH_IN_NON_HT and DYN_BANDWIDTH_IN_NON_HT parameters are present in the TXVECTOR parameter, the first 7 bits are set as shown in the second row of Table 1. The last two bits (B5, B6) of 7 bits are set according to the value of the CH_BANDWIDTH_IN_NON_HT parameter, and the fifth bit (B4) of 7 bits is set according to the DYN_BANDWIDTH_IN_NON_HT parameter.

The receiving VHT device sets the CbwINNonHtTemp value to the selected bits (B5, B6) in the scrambling sequence and maps the CbwINNonHtTemp value to the CH_BANDWIDTH_IN_NON_HT parameter as shown in Table 3. The receiving VHT device also sets the DYN_BANDWIDTH_IN_NON_HT parameter to the selected bit (B4) in the scrambling sequence. The DYN_BANDWIDTH_IN_NON_HT parameters are set as shown in Table 4.

The PHY of the receiving VHT device can not determine whether the CH_BANDWIDTH_IN_NON_HT and DYN_BANDWIDTH_IN_NON_HT parameters are present in the TXVECTOR of the transmitting PHY. Thus, the receiving VHT device always includes the CH_BANDWIDTH_IN_NON_HT and DYN_BANDWIDTH_IN_NON_HT parameters in the RXVECTOR. The PHY of the receiving VHT device can not determine whether or not the CH_BANDWIDTH_IN_NON_HT parameter is present in the TXVECTOR of the transmitting PHY, but there is no problem since the data field is scrambled in the same way.

The fourth through seventh rows of Table 1 are parameters for a device in a wireless communication network, i.e., a HEW device, according to one embodiment of the present invention.

The PHY of the receiving HEW device can not determine whether the BSS_COLOR_IN_NON_HT parameter is present in the TXVECTOR of the transmitting PHY. Thus, the receiving HEW device always includes the BSS_COLOR_IN_NON_HT parameter in the RXVECTOR.

If the BSS_ID_CH_BW_IN_NON_HT parameter, the DYN_BANDWIDTH_IN_NON_HT parameter, and the BSS_COLOR_IN_NON_HT parameter are present in the TXVECTOR parameter, the transmitting HEW device sets the first 7 bits of the scrambling sequence as in the fourth and sixth rows of Table 1.

When the BSS_COLOR_IN_NON_HT parameter is "0 ", it operates in a dynamic bandwidth allocation mode. Therefore, the BSS_ID_CH_BW_IN_NON_HT parameter is the same as the CH_BANDWIDTH_IN_NON_HT parameter. The value of the BSS_ID_CH_BW_IN_NON_HT or CH_BANDWIDTH_IN_NON_HT parameter is transmitted LSB first. For example, since the value of CBW80 is "2" and the binary value is "10", B5 is set to "0" and B6 is set to "1".

The receiving HEW device sets the CbwINNonHtTemp value to the selected bits (B5, B6) in the scrambling sequence, and maps the CbwINNonHtTemp value to the CH_BANDWIDTH_IN_NON_HT parameter as shown in Table 3. The receiving HEW device also sets the DYN_BANDWIDTH_IN_NON_HT parameter to the selected bit (B4) in the scrambling sequence. The DYN_BANDWIDTH_IN_NON_HT parameters are set as shown in Table 4.

The PHY of the receiving HEW device can not determine whether the CH_BANDWIDTH_IN_NON_HT and DYN_BANDWIDTH_IN_NON_HT parameters are present in the TXVECTOR of the transmitting PHY. Thus, the receiving HEW device always includes the CH_BANDWIDTH_IN_NON_HT and DYN_BANDWIDTH_IN_NON_HT parameters in the RXVECTOR. The PHY of the receiving HEW device can not determine whether the CH_BANDWIDTH_IN_NON_HT parameter is present in the TXVECTOR of the transmitting PHY, but there is no problem since the data field is scrambled in the same way.

When the BSS_COLOR_IN_NON_HT parameter is "1", it operates in the BSS color mode. The value of the BSS_COLOR_IN_NON_HT parameter is transmitted LSB first. For example, since BSS color ID "2" is binary "010 ", B4 is set to" 0 ", B5 is set to" 1 ", and B6 is set to" 0 ".

The receiving HEW device sets the BssColorIdINNonHtTemp value to the selected bits (B4, B5, B6) in the scrambling sequence and maps the BssColorIdINNonHtTemp value to the BSS_COLOR_IN_NON_HT parameter as shown in Table 7. The receiving HEW device also sets the BSS_COLOR_IN_NON_HT parameter to the selected bit (B3) in the scrambling sequence.

The PHY of the receiving HEW device can not determine whether the BSS_COLOR_IN_NON_HT and BSS_COLOR_ID_IN_NON_HT parameters are present in the TXVECTOR of the transmitting PHY. Thus, the receiving HEW device always includes the BSS_COLOR_IN_NON_HT and BSS_COLOR_ID_IN_NON_HT parameters in the RXVECTOR. The PHY of the receiving HEW device can not determine whether the BSS_COLOR_ID_IN_NON_HT parameter is present in the TXVECTOR of the transmitting PHY, but there is no problem since the data field is scrambled in the same way.

Next, referring to Tables 9 to 11, an embodiment will be described in which 3 bits (bits 4 (B4) to 6 (B6)) of the first 7 bits of the service field are used as BSS identification information. In this case, the scrambler initialization bit is maintained at 4 bits, and a 2-bit BSS color identifier can be transmitted.

Table 9 shows the first seven bits of the scrambling sequence according to the TXVECTOR and RXVECTOR parameters in a wireless communication network according to one embodiment of the present invention.

parameter Condition The first 7 bits of the scrambling sequence B0-B2 B3 B4 B5-B6 TXVECTOR CH_BANDWIDTH_IN_NON_HT exists, DYN_BANDWIDTH_IN_NON_HT does not exist in TXVECTOR,
BSS_COLOR_IN_NON_HT does not exist in TXVECTOR If CH_BANDWIDTH_IN_NON_HT is equal to CBW20, it is a 5 bit pseudorandom nonzero integer,
Otherwise, a 5-bit pseudorandom integer BSS_ID_CH_BW_IN_NON_HT TXVECTOR CH_BANDWIDTH_IN_NON_HT exists, DYN_BANDWIDTH_IN_NON_HT exists in TXVECTOR,
BSS_COLOR_IN_NON_HT does not exist in TXVECTOR If CH_BANDWIDTH_IN_NON_HT is equal to CBW20 and DYN_BANDWIDTH_IN_NON_HT is equal to static, it is a 4-bit pseudorandom nonzero integer,
Otherwise, a 4-bit pseudorandom integer BSS_COLOR_DYN_BW_IN_NON_HT RXVECTOR CH_BANDWIDTH_IN_NON_HT exists, DYN_BANDWIDTH_IN_NON_HT exists in RXVECTOR,
BSS_COLOR_IN_NON_HT does not exist in RXVECTOR - BSS_COLOR_DYN_BW_IN_NON_HT
Mapping to BSS_ID_CH_BW_IN_NON_HT according to Table 10

Table 10 shows BSS_ID_CH_BW_IN_NON_HT parameters among the TXVECTOR parameter and the RXVECTOR parameter used in Table 9.

BSS_COLOR_DYN_BW_IN_NON_HT (B4) Enumerated value meaning value
[B5: B6] 0 CBW20 Channel Bandwidth 20 MHz 0 0 CBW40 Channel bandwidth 40 MHz One 0 CBW80 Channel Bandwidth 80 MHz 2 0 CBW160
Or CBW80 + 80 Channel bandwidth 160 MHz or channel bandwidth 80 MHz + 80 MHz 3 One BCID0 BSS Color ID 1 0 One BCID1 BSS Color ID 2 One One BCID2 BSS Color ID 3 2 One BCID3 BSS Color ID 4 3

Table 11 shows the BSS_COLOR_DYN_BW_IN_NON_HT parameters used in Table 9.

Enumerated value value Dynamic bandwidth 0 BSS color ID One

Referring to Table 9, parameters such as BSS_COLOR_DYN_BW_IN_NON_HT and BSS_ID_CH_BW_IN_NON_HT exist as TXVECTOR parameter and RXVECTOR parameter.

Referring to Table 9, when the fifth bit B4 of the first 7 bits of the scrambling sequence is "0 ", it operates in the dynamic bandwidth allocation mode and when the fifth bit B4 is" 1 " If the fifth bit B4 is "0 ", the sixth bit and the seventh bit B5 and B6 are used for the purpose of indicating the channel bandwidth as shown in Table 10. If the fifth bit B4 is "1 ", the sixth bit and the seventh bit B5 and B6 are used for indicating the BSS color identifier as shown in Table 10. [

In another embodiment, five bits (bits 2 (B2) through 6 (B6)) of the first 7 bits of the service field may be used as the BSS identification information. In this case, two bits of the scrambler initialization bit are held.

Meanwhile, the BSS identification information can be transmitted using at least some bits of the reserved bits of the service field of the RTS / CTS frame. In this case, the dynamic bandwidth indicator may be transmitted with some of the first 7 bits of the service field, and the BSS identification information may be transmitted with some of the reserved bits of the service field.

18 is a diagram illustrating a frame control field structure in a wireless LAN.

Referring to FIG. 18, it should be noted that BSS identification information is used in the MAC layer for frame processing. To this end, the wireless LAN device sets an indicator for the MAC layer in at least some bits of the MAC frame so as to know the use of the BSS color indicator or the BSS color mode at the MAC layer.

According to one embodiment, the indicator for the MAC layer may be set to any bit in the frame control field 600. The frame control field 600 is located in the MAC header of the RTS / CTS frame.

The frame control field 600 is 16 bits and includes 16 bits including a protocol version field, a type field, a subtype field, a To DS field, a From DS field, a more flag field, a retry field, a power management field, a more data field, a protected fame field, and an order field. In particular, the To DS field, the From DS field, the more flag field, the retry field, the more data field, the protected fame field, and the order field of the frame control field are each set to 1 bit and set to "0" in the legacy control frame. Therefore, the indicator for the MAC layer can be any one of a To DS field, a From DS field, a more flag field, a retry field, a more data field, a protected fame field, and an order field.

According to another embodiment, the indicator for the MAC layer may be set to some bits in the TA field. Referring to FIG. 6, the TA field includes the address of the device transmitting the RTS frame. According to the IEEE 802.11ac standard, the MSB (Most Significant bits) of the TA field is used for the group indication and the MSB of the TA field of the RTS / CTS frame is used as a dynamic bandwidth It is used as a dynamic bandwidth indication. If the HEW device does not support dynamic bandwidth allocation, some bits in the TA field, such as the MSB, may be used as an indicator for the MAC layer.

Alternatively, some bits of the TA field, e.g., the first bit of the MSB, may be used for the dynamic bandwidth indicator and some remaining bits of the TA field may be used for the BSS color indicator. For example, the second bit of the MSB or the Nth bit from the second bit of the MSB can be used for the BSS color indicator.

According to another embodiment, the indicator for the MAC layer may use reserved bits of the service field. The reserved bit of the service field is set to "0 ", and if some bits of the reserved bit are" 1 ", the MAC layer can recognize the BSS color mode support.

19 to 22 each illustrate exemplary simultaneous transmission in a wireless LAN according to an embodiment of the present invention. The BSS color identifier of AP1 and STA1 is "1", the BSS color identifier of AP2 and STA2 is "2", the BSS color identifier of AP3 and STA3 is "3", the BSS color identifier of AP4 and STA4 is " .

Referring to FIG. 9 and FIG. 19, when AP1 has downlink data to be transmitted to STA1, it transmits an RTS frame. In this case, the RTS frame includes BSS identification information, and the BSS identification information may include a BSS color indicator and a BSS color indicator indicating the use of the BSS color. STA1, which is the destination of the RTS frame, decodes the received frame. Then, STA1 transmits a CTS frame including BSS identification information.

The STA2 located in the RTS frame protection area receives the RTS frame including the BSS identification information. Since the BSS color of the RTS frame is different from its own identifier, STA2, which is not the destination, can perform simultaneous transmission instead of NAV setting.

The STA3 located in the CTS frame protection area receives the CTS frame including the BSS identification information. Since the BSS color of the CTS frame is different from its own identifier, STA3, which is not the destination, can perform simultaneous transmission instead of NAV setting.

11, 20, and 21, when STA1 has uplink data to be transmitted to AP1, it transmits an RTS frame. At this time, the RTS frame includes the BSS identification information, and the BSS identification information may include the BSS color indicator and the BSS color identifier of STA1. AP1, which is the destination of the RTS frame, transmits the CTS frame in response to the RTS frame. At this time, the CTS frame also includes the BSS identification information.

The STA3 located in the RTS frame protection area receives the RTS frame including the BSS identification information. Since the BSS color of the RTS frame is different from its own identifier, STA3 can perform simultaneous transmission instead of NAV setting.

The STA2 located in the CTS frame protection area receives the CTS frame including the BSS identification information. Since the BSS color of the CTS frame is different from its own identifier, STA2 can perform simultaneous transmission instead of NAV setting.

Referring to FIG. 14 and FIG. 22, when AP1 and STA1 communicate, RTS / CTS frames including BSS identification information are exchanged.

The STA 4 located in the protection area of the RTS frame and the CTS frame receives the RTS / CTS frame including the BSS identification information. STA4 can perform simultaneous transmission instead of NAV setting because RTS / CTS frame BSS color is different from its own identifier.

As such, the RTS / CTS frame includes BSS identification information. The BSS identification information may be set in some bits of the service field of the RTS / CTS frame. Some bits in the service field may be some bits in the first 7 bits, or some bits in the reserved bits.

STA2, STA3, STA4 recognize the BSS color mode based on the BSS color indicator. STA2, STA3, and STA4 identify the BSS color from the RTS / CTS frame and do not set the NAV for the RTS / CTS frame transmitted from the BSS itself and the BSS color. Therefore, STA2, STA3, and STA4 can be simultaneously transmitted during the period occupied by the RTS / CTS frame.

However, if the wireless LAN device does not always set the NAV for the RTS / CTS frame transmitted in the neighboring BSS based on the BSS identification information, a collision may occur due to simultaneous transmission.

For example, referring to FIG. 9 and FIG. 19, since the BSS of the RTS frame is different from the BSS of the STA2 located in the RTS frame protection area, the STA2 can perform simultaneous transmission instead of the NAV setting. However, when the STA2 performs simultaneous transmission, the frame transmitted by the STA2 may interfere with the AP1 receiving the ACK frame, and the ACK frame may be lost.

Since the BSS of the CTS frame is different from the BSS of the STA 3 located in the CTS frame protection area, it is possible to perform simultaneous transmission instead of the NAV setting. However, when the STA3 performs simultaneous transmission, the frame transmitted by the STA3 may interfere with the STA1 receiving the data frame, and the data frame may be lost.

11, 20, and 21, when the STA3 transmits the BSS of the RTS frame differently from its BSS, the frame transmitted by the STA3 interferes with the STA1 receiving the ACK frame, Frames may be lost.

When the STA2 performs the BSS of the CTS frame differently from its own BSS, the frame transmitted by the STA2 interferes with the AP1 receiving the data frame, and the data frame may be lost.

Referring to FIG. 14 and FIG. 22, the STA 4 located in the protection area of the RTS frame and the CTS frame can perform simultaneous transmission because the BSS of the RTS / CTS frame is different from that of the BTS of the RTS / CTS frame. However, when STA4 performs simultaneous transmission, the frame transmitted by STA4 interferes with both STA1 and AP1.

In the following, methods for solving such problems will be described.

23 and 24 are diagrams for explaining a BSS identification information-based frame processing method according to an embodiment of the present invention.

23 and 24, when the wireless LAN device receives either the RTS frame or the CTS frame from the neighboring BSS, the simultaneous transmission period is calculated in consideration of the interference to the neighboring BSS by the simultaneous transmission. The wireless LAN device simultaneously transmits only the simultaneous transmittable period. For the sake of explanation, it is described that the NAV is set in a period other than the simultaneous transmittable period, but is not limited thereto.

Referring to FIG. 9 and FIG. 23, the STA2 receiving only the RTS frame of the neighboring BSS may interfere with the AP1 receiving the ACK frame when performing simultaneous transmission. Therefore, the STA2 sets the period from the period of the period field of the RTS frame until the transmission of the ACK frame to the simultaneous transmission possible period. The duration field of the RTS frame includes duration information occupied by consecutively exchanged frames since the RTS frame, and may include a CTS frame, a data frame, an ACK frame and 3 SIFS. Therefore, the simultaneous transmittable period may be a period obtained by subtracting the ACK frame transmission time and the SIFS from the period information of the RTS frame. Since the ACK frame transmission time may vary depending on the transmission rate, the ACK frame transmission time can be calculated at the slowest rate of the allowed transmission rate (for example, 6 Mbps).

STA2 does not transmit simultaneously for a period (ACK frame + SIFS) other than the simultaneous transmission available period.

The STA3 receiving only the CTS frame of the neighboring BSS may interfere with the STA1 receiving the data frame when the simultaneous transmission is performed. Therefore, the STA3 sets the period after the data frame transmission in the period of the period field of the CTS frame to the simultaneous transmittable period. The duration field of the CTS frame includes duration information occupied by consecutively exchanged frames since the CTS frame, and may include a data frame, an ACK frame and 3 SIFS. Therefore, the simultaneous transmittable period is a period corresponding to the ACK frame of the period information set in the CTS frame, and may further include SIFS. If the ACK frame is a block ACK frame, the simultaneous transmittable period can be increased.

STA3 can set the NAV for a period (data frame + SIFS) other than the simultaneous transmission available period.

Referring to FIG. 11 and FIG. 24, STA3 receiving only the RTS frame of neighboring BSS can interfere with STA1 receiving ACK frame when performing simultaneous transmission. Therefore, the STA3 sets the period before ACK frame transmission to the simultaneous transmission possible period. The simultaneous transmission available period is a period obtained by subtracting 1 SIFS from the ACK frame transmission time in the period information of the RTS frame. STA3 can set the NAV for a period (ACK frame + SIFS) other than the simultaneous transmission available period.

The STA2 receiving only the CTS frame of the neighboring BSS may interfere with the AP1 receiving the data frame when performing simultaneous transmission. Therefore, the STA2 sets the period after the data frame transmission to the simultaneous transmission possible period. The STA3 calculates a simultaneous transmittable period based on the duration field of the CTS frame. The simultaneous transmission available period is a period corresponding to an ACK frame of period information set in the CTS frame, and may further include SIFS. STA2 can set the NAV for a period (data frame + SIFS) other than the simultaneous transmission available period.

25 to 26 are flowcharts of a BSS identification information based frame processing method according to another embodiment of the present invention.

Referring to FIG. 25, the wireless LAN device receives either the RTS frame or the CTS frame (S110). The RTS frame and the CTS frame include BSS identification information, for example, a BSS color identifier.

If the BSS color of the received frame differs from its own identifier, the wireless LAN device calculates an interference level with the device that transmitted the frame (S120). The WLAN device can calculate the interference level based on the received signal strength indication (RSSI). Or the wireless LAN device may calculate the interference level based on the received signal strength and the transmit power information included in the received frame. The device transmitting the RTS / CTS frame may transmit the transmission power information so that the receiving device can determine whether to perform the NVA setting or the simultaneous transmission. Here, the interference level is an indicator for determining whether at least two devices affect the frame transmission / reception even though they are simultaneously transmitted, and may be expressed by the received signal strength or distance. Since the wireless LAN device can estimate the distance from the device that transmitted the frame based on the received signal strength or interference level, if the interference level is low, the distance between the two devices is long, and if the interference level is high, Lt; / RTI >

The wireless LAN device determines whether or not to simultaneously transmit based on the predicted interference level (S130).

When the interference level is lower than the reference value, the wireless LAN device determines simultaneous transmission instead of NAV setting (S140). That is, since the interference level is such that it does not affect the other party device, the wireless LAN device determines simultaneous transmission.

If the interference level exceeds the reference value, the wireless LAN device sets the NAV based on the received frame (S150). In other words, since simultaneous transmission can cause interference to the other party device, the wireless LAN device sets the NAV.

Referring to FIG. 9, the STA2 located in the RTS frame protection area can determine whether or not to simultaneously transmit based on the interference level with the AP1. The STA3 located in the CTS frame protection area can determine whether or not to transmit simultaneously based on the interference level with the STA1. Referring to FIG. 11, the STA 3 located in the RTS frame protection area can determine whether or not to simultaneously transmit based on the interference level with the STA 1. The STA2 located in the CTS frame protection area can determine whether to transmit simultaneously based on the interference level with the AP1.

In this manner, when the BSS of the received frame is different from the BSS of the received frame, the wireless LAN device can determine whether or not to simultaneously transmit the frame based on the interference level between the BSS and the other party.

Referring to FIG. 26, the wireless LAN device receives either the RTS frame or the CTS frame (S210). The RTS frame and the CTS frame include BSS identification information, for example, a BSS color identifier.

If the BSS color of the received frame differs from its own identifier, the wireless LAN device calculates an interference level with the device that transmitted the frame (S220). The wireless LAN device can calculate the interference level based on at least one of the received signal strength and the transmission power information included in the received frame.

The wireless LAN device determines the transmission power for simultaneous transmission based on the interference level with the neighboring BSS (S230). The WLAN device can lower the transmission power to reduce the interference to the neighboring BSS based on the received signal strength and the transmission power information included in the received frame.

The wireless LAN device simultaneously transmits the determined transmission power (S240).

In this way, when the BSS of the received frame is different from the BSS of the wireless LAN device, the wireless LAN device can reduce the interference by reducing the transmission power.

FIG. 27 is a flowchart of a BSS identification information based frame processing method according to another embodiment of the present invention, and FIG. 28 is a view for explaining a BSS identification information based frame processing method according to still another embodiment of the present invention.

Referring to FIG. 14 and FIG. 27, the wireless LAN device STA4 receives an RTS frame (S310). The RTS frame includes BSS identification information, for example, a BSS color identifier.

When the BSS color of the RTS frame differs from its own identifier, the wireless LAN device STA4 calculates an interference level with the device AP1 that transmitted the RTS frame (S320). The wireless LAN device STA4 can calculate the interference level based on at least one of the received signal strength and the transmission power information included in the received frame.

The wireless LAN device determines whether simultaneous transmission is performed based on the interference level (S330).

The wireless LAN device STA4 sets the period corresponding to the period information of the RTS frame to the simultaneous transmittable period when the interference level is lower than the reference value ("condition A") (S332).

If the interference level exceeds the reference value (referred to as "condition B"), the wireless LAN device STA4 sets the period from the period information of the RTS frame to the data frame transmission period at the simultaneous transmission possible period (S334). The simultaneous transmission available period is a period obtained by subtracting the ACK frame transmission time and the SIFS from the period information of the RTS frame. The wireless LAN device STA4 can set the NAV for a period (ACK frame + SIFS) other than the simultaneous transmission available period.

The wireless LAN device STA4 receives the CTS frame (S340). The CTS frame includes BSS color information.

When the BSS color of the CTS frame is different from its own identifier, the wireless LAN device STA4 calculates an interference level with the device STA1 that transmitted the CTS frame (S350). The wireless LAN device STA4 can calculate the interference level based on at least one of the received signal strength and the transmission power information included in the received frame.

The wireless LAN device determines whether or not to simultaneously transmit based on the interference level (S360).

The wireless LAN device STA4 sets the period corresponding to the period information of the CTS frame to the simultaneous transmittable period when the interference level is below the reference value ("condition C") (S362).

If the interference level exceeds the reference value (referred to as "condition D"), the wireless LAN device STA4 sets the ACK frame transmission period as the simultaneous transmission possible period in the period information of the CTS frame (S364). The simultaneous transmission available period is a period corresponding to an ACK frame of period information set in the CTS frame, and may further include SIFS. The wireless LAN device STA4 can set the NAV for a period (data frame + SIFS) other than the simultaneous transmission available period.

The wireless LAN device STA4 performs simultaneous transmission in the simultaneous transmittable period (S370).

Referring to FIG. 28, the simultaneous transmission period according to the conditions A and C is set as shown in (a). Since the interference level is low, the wireless LAN device STA4 simultaneously transmits the period information of the RTS / CTS frame without setting the NAV. On the other hand, the wireless LAN device STA4 may be considered to be far away from the device that transmitted the RTS / CTS frame.

Simultaneous transmission periods by conditions A and D are set as shown in (b). The wireless LAN device STA4 does not set the NAV for the period information of the RTS frame since the interference level does not affect the device that transmitted the RTS frame. However, the wireless LAN device STA4 can set the NAV for the data frame transmission period since the interference level is such that it can affect the device that transmitted the CTS frame. On the other hand, the wireless LAN device STA4 can be considered to be close to the device STA1 which is far from the device AP1 that has transmitted the RTS frame, but has transmitted the CTS frame.

The simultaneous transmission period according to the condition B and the condition C is set as shown in (c). The wireless LAN device STA4 does not set the NAV for the duration information of the CTS frame since the interference level does not affect the device that transmitted the CTS frame. However, the wireless LAN device STA4 can set the NAV in the ACK frame transmission period since the interference level is such that it can affect the device that transmitted the RTS frame. On the other hand, the wireless LAN device STA4 may be considered to be close to the device AP1 which is far from the device STA1 that has transmitted the CTS frame, but has transmitted the RTS frame.

The simultaneous transmittable period by the conditions B and D is set as shown in (d). The wireless LAN device STA4 may not simultaneously transmit the data frame and the ACK frame until the interference level is sufficient to affect the device that transmitted the RTS / CTS frame. On the other hand, the wireless LAN device STA4 may be close to the device that transmitted the RTS / CTS frame.

On the other hand, the wireless LAN device STA4 can determine the transmission power for simultaneous transmission based on the interference level with the neighboring BSS. The WLAN device can lower the transmission power to reduce the interference to the neighboring BSS based on the received signal strength and the transmission power information included in the received frame.

FIG. 29 is a flowchart of a method of transmitting BSS identification information in a wireless LAN according to an embodiment of the present invention, and FIG. 30 is a flowchart of a method of simultaneously transmitting frames in a wireless LAN according to an embodiment of the present invention.

Referring to FIG. 29, the WLAN device generates an RTS / CTS frame including BSS identification information (S410). The BSS identification information may include a BSS color indicator and a BSS color identifier, and is included in the designated bits of the service field. The BSS identification information may use three bits, four bits, five bits, or some bits of the reserved bits of the service field from the first 7 bits of the service field. The first 7 bits of the scrambled service field corresponds to the first 7 bits of the scrambling sequence. The WLAN device transmits an indicator including the BSS color mode operation in the MAC layer. The indicator for the MAC layer may be set to any of the frame control field and the TA field of the MAC frame. Or an indicator for the MAC layer may be set to some bits of the reserved bits of the service field.

The wireless LAN device transmits an RTS / CTS frame (S420).

Referring to FIG. 30, the wireless LAN device receives an RTS / CTS frame (S510). Here, the wireless LAN device may be a HEW device.

The WLAN device identifies the BSS color indicator included in the RTS / CTS frame (S520). The BSS identification information including the BSS color indicator may be extracted from the designated bits of the service field.

If the RA field of the received frame is different from its own address, the wireless LAN device extracts the BSS color identifier included in the RTS / CTS frame (S530). The wireless LAN device compares its BSS color identifier with the BSS color identifier of the received frame (S540).

If the BSS color identifiers are the same, the wireless LAN device sets a NAV for a period corresponding to the duration field of the received frame (S550).

If the BSS color identifier is different, the wireless LAN device may set at least a part of the period corresponding to the period field of the received frame to a simultaneous transmittable period (S560). The wireless LAN device may calculate the transmittable period based on the interference level or distance to the transmitting device, or the BSS color identifier does not set a NAV for another RTS / CTS frame. Or a wireless LAN device can transmit at a lower transmission power during simultaneous transmission.

31 and 32 each illustrate a signal field including BSS information in a frame according to an embodiment of the present invention.

Referring to FIGS. 31 and 32, the BSS information may be set to some bits of the signal field of the PHY frame. In particular, the BSS identification information included in the HEW signal field enables the HEW device to identify the BSS of the transmission frame.

In the downlink frame, the HEW signal field includes a 10-bit ID field (400), and some bits of the identifier field (400) include BSS information. The identifier field 400 includes a first field 410 indicating a downlink frame, a second field 430 including a BSS color identifier, and a third field 430 including a partial association ID (partial AID, PAID) Field 450 as shown in FIG. The first field 410 is one bit and is used to define the remaining 9 bits, for example, a downlink. The second field 430 includes a BSS color identifier, and may be, for example, 3 bits. The third field 450 contains a 6-bit PAID and is used to identify the destination. The PAID in the downlink frame can be defined as Equation (1).

Here, xor represents a bitwise exclusive OR operation, dec (A [b: c]) represents a decimal operation in which ^b is scaled to 2 ⁰ and c is scaled to 2 ^cb , and AID [b: c] denotes bits b to c of the AID, and BSSID [b: c] denotes bits b to c of the BSSID. The association ID (AID) is an identifier assigned to the STA by the AP while the STA is associated with the AP. A basic service set identifier (BSSID) is an identifier for identifying a BSS.

In the UL frame, the HEW signal field includes a 10-bit identifier field 500, and some bits of the identifier field 500 include BSS information. The identifier field 500 includes a first field 510 indicating an uplink frame and a second field 530 including BSS identification information. The first field 510 is one bit, indicating an uplink. The second field 530 is 9 bits and may include some bits of the BSSID (e.g., 9 bits of the BSSID).

The wireless LAN device can identify the BSS of the received frame based on the BSS information of the signal field.

The AP receives the uplink frame and decodes the PSDU if the group ID field is 0 and the PAID field is equal to BSSID [39:47]. Otherwise, the AP does not decode the PSDU. The STA receives the downlink frame, and the group ID field is 63 and the PAID field is dec (AID [0: 8] + dec (BSSID [44:47] XOR BSSID [40:43] If equal to ^ 9 or 0, decodes the PSDU. Otherwise, the STA does not decode the PSDU.

Alternatively, if the PAID field of the received uplink frame is equal to BSSID [39:47], the AP decodes the PSDU. Otherwise, the AP does not decode the PSDU. If the PAID field of the received downlink frame is equal to (dec (AID [0: 8] + dec (BSSID [44:47] XOR BSSID [40:43] The STA decodes the PSDU. Otherwise, the STA does not decode the PSDU.

The method of the present invention described above with reference to the drawings is performed in a wireless LAN device including a processor, a memory and a transceiver. The wireless LAN device may store instructions for carrying out the method of the present invention or may be stored in a memory for temporarily storing and loading instructions from the storage device and executing instructions stored in memory or loaded into the beamforming A processor that processes the feedback method, and a transceiver that transmits frames generated by the processor or receives frames transmitted over the wireless communication network. 1. The processor may include the baseband processor 10 of FIG. 1 and the memory may include the memory 40 of FIG. 1 and the transceiver may include the RF transceiver 20 and the antenna unit 30 of FIG. . ≪ / RTI >

While various embodiments of the present invention have been described above, it is to be understood that these various embodiments are not necessarily implemented alone, and that more than two embodiments may be combined. While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, It belongs to the scope of right.

Claims (20)

A method of transmitting a frame of a device in a wireless local area network (WLAN)
Generating a frame including Basic Service Set (BSS) identification information, and
And transmitting the frame,
Wherein the frame is a request to send (RTS) frame or a clear to send (CTS) frame. The method of claim 1,
Wherein the BSS identification information is included in a service field of the frame. 3. The method of claim 2,
Wherein the BSS identification information includes a BSS color identifier. 3. The method of claim 2,
Wherein the BSS identification information includes an indicator indicating a mode using the BSS identification information. The method of claim 1,
Wherein the frame includes a service field,
The first 7 bits of the service field correspond to the first 7 bits of the scrambling sequence,
Wherein a predetermined bit of the first 7 bits of the scrambling sequence includes the BSS identification information. The method of claim 5,
Wherein the fourth to seventh bits of the first 7 bits of the scrambling sequence include the BSS identification information. The method of claim 6,
Wherein the fourth bit of the first 7 bits of the scrambling sequence includes an indicator indicating transmission of the BSS identification information,
Wherein the fifth through seventh bits of the first 7 bits of the scrambling sequence comprise a BSS color identifier. The method of claim 5,
Wherein the fifth to seventh bits of the first 7 bits of the scrambling sequence comprise the BSS identification information. 9. The method of claim 8,
Wherein the fifth bit of the first 7 bits of the scrambling sequence includes an indicator indicating transmission of the BSS identification information,
Wherein the sixth through seventh bits of the first 7 bits of the scrambling sequence comprise a BSS color identifier. The method of claim 5,
Wherein the third to seventh bits of the first 7 bits of the scrambling sequence include the BSS identification information. The method of claim 5,
Wherein a predetermined bit among the first 7 bits of the scrambling sequence includes a first value corresponding to an indicator indicating transmission of BSS identification information and a second value corresponding to an indicator indicating a bandwidth used. The method of claim 1,
The frame including a frame control field,
A predetermined bit of the frame control field is
And informing the Medium Access Control (MAC) layer of the use of the BSS identification information. The method of claim 1,
Wherein the frame includes a service field,
At least some bits from the eighth through sixteenth bits of the service field
And informing the Medium Access Control (MAC) layer of the use of the BSS identification information. A method of receiving a frame of a device in a wireless local area network (WLAN)
Receiving a frame, and
And obtaining basic service set (BSS) identification information included in the frame,
Wherein the frame is a request to send (RTS) frame or a clear to send (CTS) frame. The method of claim 14,
Wherein the service field of the frame includes the BSS identification information. 16. The method of claim 15,
The first 7 bits of the service field correspond to the first 7 bits of the scrambling sequence,
Wherein a predetermined bit of the first 7 bits of the scrambling sequence indicates the BSS identification information. 17. The method of claim 16,
The step of obtaining the BSS identification information
Selecting a bit to which the BSS identification information is transmitted from among the first 7 bits of the scrambling sequence and mapping the value of the selected bit to a designated parameter to obtain the BSS identification information. The method of claim 14,
Determining whether or not to simultaneously transmit frames based on the BSS identification information
≪ / RTI > The method of claim 18,
Wherein the step of determining whether to transmit the frames simultaneously
And determining at least a part of period information corresponding to the period field of the frame as a frame synchronous transmission period, when the BSS identification information of the frame is different from the BSS identification information of the frame. The method of claim 18,
Wherein the step of determining whether to transmit the frames simultaneously
And determining whether to transmit the frame simultaneously based on the interference level with the device that transmitted the frame, when the BSS identification information of the frame is different from the BSS identification information of the frame.

Images