KR20160016582A - Method for transmitting and receiving frame in wireless local area network and apparatus for the same - Google Patents

Abstract

A method and an apparatus for transceiving a frame in a wireless local area network (LAN) are disclosed. A communications method of a station comprises the steps of: generating a first frame including information on an exclusive section for transmitting or receiving a data frame; and transmitting the first frame. Accordingly, a performance of the wireless LAN can be increased.

Description

BACKGROUND OF THE INVENTION Field of the Invention [0001] The present invention relates to a method and apparatus for transmitting / receiving frames in a wireless LAN,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless LAN technology, and more particularly, to a technology for coexistence between a wireless LAN technology and other communication technologies.

With the development of information and communication technology, various wireless communication technologies are being developed. Among them, a wireless local area network (WLAN) may be a personal digital assistant (PDA), a laptop computer, a portable multimedia player (PMP), a smart phone A smart phone, a tablet PC, or the like, to wirelessly connect to the Internet in a home, an enterprise, or a specific service providing area.

The standard for wireless LAN technology is being developed as the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard. As the spread of wireless LANs is activated and applications using the wireless LANs are diversified, there is a growing need for new wireless LAN technologies that support higher throughput than existing wireless LAN technologies. Very high throughput (VHT) Wireless LAN technology is a proposed technology to support data rates of over 1Gbps. Among them, the wireless LAN technology according to the IEEE 802.11ac standard is a technology for providing an ultra high throughput in a band below 6 GHz, and the wireless LAN technology according to the IEEE 802.11ad standard is a technology for providing an ultra high throughput in a 60 GHz band.

In addition, standards for various wireless LAN technologies have been defined and technology development is under way. Typically, the wireless LAN technology according to the IEEE 802.11af standard is a technology defined for operation of a wireless LAN in a TV idle band, and the wireless LAN technology according to the IEEE 802.11ah standard operates at a low power in a band below 1 GHz The wireless LAN technology according to the IEEE 802.11ai standard is a technology defined for fast initial link setup (FILS) in a wireless LAN system. Recently, IEEE 802.11ax standardization for the purpose of improving frequency efficiency in a dense environment in which a plurality of base stations and terminals exist is proceeding.

In addition to the wireless LAN, bluetooth, long term evolution-unlicensed (LTE-U), zigbee, etc., can operate in industrial scientific medical (ISM) bands. Since the wireless LAN technology operates with different protocols from other communication technologies, frames transmitted and received based on the wireless LAN technology may collide with frames transmitted and received based on other communication technologies. The collision between these frames can degrade the performance of the wireless LAN.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method and apparatus for frame transmission / reception for coexistence between wireless LAN technology and other communication technologies.

According to an aspect of the present invention, there is provided a communication method performed in a first station, the method comprising: generating a first frame including information on a monopoly section for transmitting or receiving a data frame; Wherein the exclusive period has a transmission interval and an interval of the first frame, and communication of a station other than the first station in the interval is allowed.

Here, the first frame includes a schedule information field, and the schedule information field includes an interval field indicating a duration time of the exclusive section and a starting time field indicating a starting time point of the exclusive interval indicated by the interval field .

Here, the first frame includes a schedule information field, and the schedule information field may include a start time field indicating a start time of the exclusive section and an end time field indicating an end time of the exclusive section.

Here, the first frame includes a schedule information field, and the schedule information field includes a start time field indicating a start time of a communication interval including the monopoly interval and a period in which communication of a station other than the first station is allowed, An interval field indicating the interval time of the exclusive section, an interval field indicating the interval time between the exclusive intervals, and an end time indication field including information indicating the end time of the communication interval.

The communication method may further include receiving a response frame from an access point to which the first station is connected in response to the first frame.

Here, the communication method may further include obtaining a second frame including information of the exclusive period from an access point to which the first station is connected.

Here, the communication method may further include receiving a data frame from a second station in a reception interval indicated by the information of the exclusive period.

Here, the communication method may further include transmitting a data frame to a second station in a transmission interval indicated by the information of the exclusive period.

Here, the first frame may include information of a plurality of exclusive periods indicating different transmission periods or reception periods.

Here, the first frame may be transmitted based on a first communication protocol, and the data frame may be transmitted or received based on a second communication protocol.

Here, the first station may support a plurality of communication protocols.

According to another aspect of the present invention, there is provided a communication method performed in a first station, the method comprising: receiving a first frame including information on an exclusive period for transmitting or receiving a data frame from a second station; And transmitting a second frame in response to the first frame, wherein the exclusive period has an interval with a transmission interval of the first frame, and wherein the communication of a station other than the second station in the interval Is allowed.

Here, the first frame includes a schedule information field, and the schedule information field includes an interval field indicating a duration time of the exclusive section and a starting time field indicating a starting time point of the exclusive interval indicated by the interval field .

Here, the second frame may be a response frame.

Here, the second frame may include the information of the exclusive period.

The method includes receiving an RTS frame from a third station, and when an interval indicated by the interval field included in the RTS frame is overlapped with an exclusive interval indicated by the interval field included in the first frame, And transmitting the guard frame to prevent collision of frames in the overlapped section.

Here, the duration field of the guard frame may indicate a duration of time from the end of the guard frame to the beginning of the exclusive period.

Here, the communication method may further include a step of transmitting a guard frame in a predetermined interval before a start time of the exclusive period to prevent a frame collision in the exclusive period.

Here, the duration field of the guard frame may indicate a duration of time from the end of the CTS frame to the end of the monopoly duration.

Here, the first frame may be transmitted based on a first communication protocol, and the data frame may be transmitted or received based on a second communication protocol.

According to the present invention, a NAV delayed by a predetermined time through the SNAV-A frame or the SNAV-C frame can be set. The set NAV can be canceled by the SNAV-D frame. Accordingly, a collision between a frame transmitted / received based on the wireless LAN technology and a frame transmitted / received based on another communication technology can be prevented. In addition, since the channel connection through the communication technology other than the wireless LAN technology is not excessively limited by the NAV set based on the SNAV-A frame or the SNAV-C frame, the fairness between the wireless LAN technology and other communication technologies Can be guaranteed.

1 is a block diagram showing 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.
FIG. 4 is a diagram showing a relationship between frames. FIG.
5 is a conceptual diagram for explaining a frame transmission procedure according to the CSMA / CA scheme for avoiding collision between frames in a channel.
6 is a timing chart showing a case where collision between frames occurs.
7 is a timing diagram illustrating an embodiment of a frame transmission / reception method for coexistence of a wireless LAN and Bluetooth.
8 is a timing diagram illustrating another embodiment of a frame transmission / reception method for coexistence of a wireless LAN and Bluetooth.
9 is a timing diagram showing another embodiment of a frame transmission / reception method for coexistence of a wireless LAN and Bluetooth.
10A is a block diagram showing a first embodiment of an SNAV-A frame.
10B is a block diagram showing a second embodiment of the SNAV-A frame.
10C is a block diagram showing a third embodiment of the SNAV-A frame.

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 like parts are denoted by similar reference numerals throughout the specification.

A basic service set (BSS) in a wireless local area network (WLAN) (hereinafter referred to as "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 block diagram showing the structure of a wireless LAN device.

1, a 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, The baseband processor 10 performs the baseband related signal processing described herein, and may include 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 (MAC hardware), but the present invention is not limited thereto. The PHY processor 15 may include 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 may include 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 unit 30 may include 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 can 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. Alternatively, 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. In addition, the transmission signal processing unit 100 includes a space-time block code (STBC) encoder for spreading a property point from N _SS spatial streams to N _STS space-time streams, and a spatial mapper for mapping the received signals to transmit chains. 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 100 may insert a cyclic shift diversity (CSD) before or after the inverse Fourier transform to prevent unintended 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. Further, 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 may include 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.

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

Referring to FIG. 4, 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 a distributed coordination function IFS (DIFS) 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 a type field and a 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 station STA1 denotes a transmitting station to which data is to be transmitted, and a second station STA2 denotes a receiving station that receives data transmitted from the first station STA1. The third station STA3 may be located in an area capable of receiving a frame transmitted from the first station STA1 and / or a frame transmitted from the second station STA2.

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

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

On the other hand, when receiving the RTS frame, the third station 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 the CTS frame is received, the third station STA3 may transmit the CTS frame in a frame transmission period (for example, SIFS + data frame + SIFS + ACK frame) continuously transmitted subsequently using the interval information included in the CTS frame You can set the NAV timer for. When the third station STA3 receives a new frame before the NAV timer expires, the third station STA3 can update the NAV timer using the interval information included in the new frame. The third station STA3 does not attempt to access the channel until the NAV timer expires.

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

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

On the other hand, with regard to coexistence with other communication technologies (e.g., bluetooth, long term evolution-unlicensed, zigbee, etc.) in a wireless LAN, a combo chip, There is a problem in that interference occurs when a frame is transmitted and interference that occurs when a frame is received. For reference, embodiments for solving the coexistence problem between the wireless LAN technology and the Bluetooth technology will be mainly described below, but the present invention is not limited thereto. That is, the embodiments of the present invention can be applied not only to the coexistence of the wireless LAN technology and the Bluetooth technology but also to solve the coexistence problem between the wireless LAN technology and other communication technologies (for example, LTE-U, ZigBee, etc.) have.

In a frame transmission mode, a station equipped with a combo chip supporting wireless LAN technology and Bluetooth technology (or LTE-U, ZigBee, etc.) can know when a frame transmission according to the Bluetooth scheme occurs. Therefore, the station can prevent a collision between a frame transmitted in a wireless LAN scheme and a frame transmitted in a Bluetooth scheme, thereby ensuring frame transmission according to the Bluetooth scheme.

However, the frame received in the Bluetooth mode in the frame receiving mode may collide with the frame received in the wireless LAN mode. For example, in a case where a station that does not know information about a frame transmitted in a Bluetooth scheme in the BSS transmits a frame in a wireless LAN scheme, a frame transmitted in a wireless LAN scheme may collide with a frame transmitted in a Bluetooth scheme. In particular, according to the Bluetooth scheme, a voice data frame having a higher priority than another data frame can be generated every about 4 to 5 ms and can have a length corresponding to about 600 μs × n (n = 1, 3, 5) . The possibility of collision between such a voice data frame and a frame transmitted in a wireless LAN scheme is higher, and thus quality of service (QoS) and quality of experience (QoE) can be rapidly deteriorated in both the wireless LAN system and the Bluetooth system. Further, when the channel condition is poor and a lot of frames are retransmitted, QoS and QoE may be further degraded in both the wireless LAN system and the Bluetooth system.

6 is a timing chart showing a case where collision between frames occurs.

Referring to FIG. 6, an access point (AP), a first station STA1 and a second station STA2 may form a BSS1. The third station STA3 may operate in a Bluetooth manner and may not belong to the BSS1. The first station STA1 and the second station STA2 may be associated with an access point (AP). The second station STA2 may include a combo chip supporting the wireless LAN technology and the Bluetooth technology, and may be connected to the third station STA3 through the Bluetooth scheme. Here, the third station STA3 may denote a master, and the second station STA2 may denote a slave.

The third station STA3 may transmit the data frame 600 (e.g., voice data frame) to the second station STA2 in a Bluetooth manner. The data frame 600 may have a size corresponding to 600 microseconds. Data frames 600 and 605 transmitted in a Bluetooth manner can be transmitted at intervals of 2400 microseconds. The second station STA2 may receive the data frame 600 but the access point AP and the first station STA1 may not receive the data frame 600. [ That is, the access point AP and the first station STA1 may be located outside the frame transmission range of the third station STA3. When the access point AP and the first station STA1 do not recognize the existence of the data frame 600 transmitted from the third station STA3, the access point AP and the first station STA1 transmit the frames 601, 602, 603, 604, and 606, respectively.

An access point (AP) that wants to transmit a data frame can transmit an RTS frame 601 after a contention window according to random backoff when the channel is idle during DIFS. The first station STA1 may transmit the CTS frame 602 after SIFS from the end of the RTS frame 601 in response to the RTS frame 601 when the first station STA1 successfully receives the RTS frame 601. [ The access point AP may transmit the data frame 603 to the first station STA1 after SIFS from the end of the CTS frame 602 upon successful receipt of the CTS frame 602. [

The access point AP may not receive from the first station STA1 an ACK frame which is a response to the reception of the data frame 603 within the ACK timeout from the end of the data frame 603. [ In this case, the access point AP may determine that the data frame 603 has not been successfully received at the first station STA1, and accordingly retransmits the data frame 604 to the first station STA1 .

Meanwhile, the transmission period of the data frame 604 transmitted in the wireless LAN scheme may be overlapped with the transmission period of the data frame 605 transmitted in the Bluetooth scheme. In this case, the first station STA1 can receive the data frame 604 successfully because it is not interfered by the transmission of the data frame 605. [ However, since the second station STA2 is interfered by the transmission of the data frame 604 (i.e., a collision between the data frame 604 and the data frame 605 occurs) I can not.

In order to prevent a collision between a frame transmitted in a wireless LAN mode and a frame transmitted in a Bluetooth mode, a time interval for transmission in a wireless LAN scheme and a time interval for transmission in a Bluetooth scheme can be distinguished in a time axis.

7 is a timing diagram illustrating an embodiment of a frame transmission / reception method for coexistence of a wireless LAN and Bluetooth.

Referring to FIG. 7, an access point AP and a first station STA1 may form a BSS1. The second station STA2 may operate in a Bluetooth manner and may not belong to the BSS1. The first station STA1 may be connected to an access point (AP). The first station STA1 may include a combo chip supporting the wireless LAN technology and the Bluetooth technology, and may be connected to the second station STA2 through the Bluetooth scheme. Here, the second station STA2 may mean a master, and the first station STA1 may mean a slave. The time interval can be classified into BT transmission interval (BT TX1, BT TX2, BT TX3) and WLAN transmission interval (WLAN TX1, WLAN TX2). The frames 700, 705 and 710 can be transmitted and received in the BT transmission periods BT1, BT2 and BT3 and the frames 701 and 702 can be transmitted and received in the WLAN transmission period (WLAN TX1 and WLAN TX2) 702, 703, 704, 706, 707, 708, 709 can be transmitted and received.

In BT TX1, the second station STA2 may transmit the data frame 700 to the first station STA1 in a Bluetooth manner. The first station STA1 can successfully receive the data frame 700 because there is no transmission of another frame during the BT transmission period. In the WLAN TX1, the first station STA1 may request frame transmission by transmitting a pawer save-poll (PS-Poll) frame 701 in a wireless LAN manner. Thereafter, frames 702, 703 and 704 may be transmitted and received between the access point AP and the first station STA1.

In BT TX2, the second station STA2 may transmit the data frame 705 to the first station STA1 in a Bluetooth manner. The first station STA1 can successfully receive the data frame 705 because there is no transmission of another frame during the BT transmission period. In WLAN TX2, the first station STA1 may request frame transmission by transmitting a WMF (WiFi multimedia) trigger frame 706. [ Thereafter, frames 707, 708 and 709 may be transmitted and received between the access point AP and the first station STA1. In BT TX3, the second station STA2 may transmit the data frame 710 to the first station STA1 in a Bluetooth manner. The first station STA1 can successfully receive the data frame 710 because there is no transmission of another frame during the BT transmission interval.

8 is a timing diagram illustrating another embodiment of a frame transmission / reception method for coexistence of a wireless LAN and Bluetooth.

Referring to FIG. 8, an access point (AP), a first station STA1 and a second station STA2 may form a BSS1. The third station STA3 may operate in a Bluetooth manner and may not belong to the BSS1. The first station STA1 and the second station STA2 may be connected to an access point AP. The second station STA2 may include a combo chip supporting the wireless LAN technology and the Bluetooth technology, and may be connected to the third station STA3 through the Bluetooth scheme. Here, the third station STA3 may mean a master, and the second station STA2 may mean a slave.

The third station STA3 may transmit the data frame 800 (e.g., voice data frame) to the second station STA2 in a Bluetooth manner. The second station STA2 can receive the data frame 800 from the third station STA2 and know that the data frame 802 will be transmitted 2400s after the end of the data frame 800. [ The second station STA2 may transmit the guard frame 801 in a wireless LAN mode to prevent collision of the data frame 802. [ The guard frame 801 limits the frame transmission of other communication entities (i.e., the access point AP, the first station STA1, etc.) from the end of the guard frame 801 to the end of the data frame 802 (E.g., interval information from the end point of the guard frame 801 to the end point of the data frame 802). Each of the communication entities receiving the guard frame 801 can set the NAV based on the information contained in the guard frame 801. [ Since the frame transmission of other communication entities is restricted from the end of the guard frame 801 to the end of the data frame 802, the second station STA2 transmits the data frame 802 from the third station STA3 You can receive it successfully. Meanwhile, when the NAV is terminated, the access point AP and the first station STA1 can transmit and receive the frames 803, 804, 805, and 806 in a wireless LAN system.

However, the method of preventing the collision between the frame transmitted through the guard frame 801 and the frame transmitted through the Bluetooth method has various problems. First, when the NAV is set to be long by the guard frame 801, resources are wasted because the other communication entities can not access the channel for the interval in which the NAV is set, and only the communication object operating in the Bluetooth mode It is contrary to fairness because it allows channel access. Secondly, when the NAV is set to be short by the guard frame 801, the frame transmitted in the Bluetooth scheme by the frame transmitted in the wireless LAN scheme may not be protected. That is, a frame transmitted in a wireless LAN scheme and a frame transmitted in a Bluetooth scheme may collide with each other. Third, since the guard frame 801 must be transmitted every period in which a frame is expected to be transmitted in a Bluetooth manner, resources may be wasted by frequent transmission of the guard frame 801. [ Particularly, when the guard frame 801 is transmitted at a low rate for compatibility with a legacy communication entity, resource waste becomes more serious.

9 is a timing diagram showing another embodiment of a frame transmission / reception method for coexistence of a wireless LAN and Bluetooth.

Referring to FIG. 9, an access point (AP), a first station STA1 and a second station STA2 may form a BSS1. The third station STA3 may operate in a Bluetooth manner and may not belong to the BSS1. The first station STA1 and the second station STA2 may be connected to an access point AP. The second station STA2 may include a combo chip supporting the wireless LAN technology and the Bluetooth technology, and may be connected to the third station STA3 through the Bluetooth scheme. Here, the third station STA3 may mean a master, and the second station STA2 may mean a slave.

The third station STA3 may transmit the data frame 900 (e.g., a voice data frame) to the second station STA2 in a Bluetooth manner. The second station STA2 may receive the data frame 900 from the third station STA2 and then know that the data frames 906,912 and 915 will be transmitted in 2400s intervals. The second station STA2 may generate a scheduled NAV-announcement (SNAV-A) frame 901 to prevent collision of the data frame 906. At least one of the control frame, the management frame and the data frame specified in IEEE 802.11 may be used as the SNAV-A frame 901, or a newly defined frame may be used. For example, the SNAV-A frame 901 may be defined as an action frame belonging to a management frame as follows.

10A is a block diagram showing a first embodiment of an SNAV-A frame, FIG. 10B is a block diagram showing a second embodiment of an SNAV-A frame, FIG. 10C is a block diagram of a third embodiment of the SNAV- Fig.

10A through 10C, the SNAV-A frame 1000 includes a MAC header 1010, a category field 1020, an action field 1030, a transmitter address field 1040, a dialog token field 1050, a schedule counter field 1060, and at least one schedule information field 1071, 1072, ..., 107n. The action field 1030 can indicate the type of the current frame. For example, if action field 1030 is set to binary 00, it may indicate that the current frame is SNAV-A frame 1000. The transmitter address field 1040 may be set to the MAC address of the communication entity transmitting the SNAV-A frame 1000. Therefore, the transmitter address field of the SNAV-A frame 901 of FIG. 9 may be set to the MAC address of the second station STA2. Dialogue token field 1050 may have a unique value for identification of SNAV-A frame 1000. That is, the communication entity receiving the SNAV-A frame 1000 can identify the SNAV-A frame 1000 using the transmitter address field 1040 and the dialogue token field 1050. [ The schedule counter field 1060 may indicate the number of schedule information fields 1071, 1072, ..., 107n included in the SNAV-A frame 1000.

Each schedule information field 1071, 1072, ..., 107n may indicate information of an exclusive duration in which channel occupation is required for transmission or reception of a data frame. The SNAV-A frame 1000 may include a plurality of schedule information fields 1071, 1072, ..., 107n.

According to the first embodiment, the schedule information fields 1071, 1072, ..., 107n include start time fields 1071-1, 1702-1, ..., 107n-1 of the exclusive section, -2, 1702-2, ..., 107n-2. The interval fields 1071-2, 1702-2, ..., 107n-2 may indicate a duration time of an exclusive section in which channel occupation is required for transmission or reception of a data frame. The start time fields 1071-1, 1702-1, ..., 107n-1 of the exclusive section designate the start time of the exclusive section indicated by the interval fields 1071-2, 1702-2, ..., 107n-2 .

According to the second embodiment, the schedule information fields 1071, 1072, ..., and 107n include start time fields 1071-1, 1702-1, ..., 107n-1 of the exclusive section and end time ) Fields 1071-3, 1702-3, ..., 107n-3. The start time fields 1071-1, 1072-1, ..., 107n-1 of the respective exclusive sections can indicate the start time of the exclusive section, and the end time fields 1071-3, 1702-3 , ..., 107n-3) may indicate the ending time of the corresponding exclusive section.

According to the third embodiment, the schedule information fields 1071, 1072, ..., 107n include start time fields 1071-4, 1702-4, ..., 107n-4 of communication sections, interval fields 1071-2, The interval fields 1071-5, 1702-5, ... 107n-5 and the communication section end point instruction fields 1071-6, 1702-6, ... 107n-6, . ≪ / RTI > The start time fields 1071-4, 1702-4, ... 107n-4 of the communication section are divided into a communication period including at least one exclusive section (for example, from the end of the data frame 900 to the data frame 915 (A section from the end of the SNAV-A frame 901 to the end of the data frame 915). When there are a plurality of schedule information fields 1071, 1072, ..., 107n, only the first schedule information field 1071 may include the start time field 1071-4 of the communication interval. The interval fields 1071-5, 1702-5, ..., 107n-5 may indicate an interval time between exclusive intervals. The interval field 1071-5 included in the first schedule information field 1071 is a time interval between the data frame 900 and the data frame 906 or between the SNAV-A frame 901 and the data frame 906 The interval time can be indicated. The end time indication fields 1071-6, 1702-6, ..., 107n-6 of the communication section may include information indicating an end time of the communication section. The information indicating the end time of the communication section may be a section time of the communication section, a number of exclusive sections included in the communication section, or an end time of the communication section. When there are a plurality of schedule information fields 1071, 1072, ..., 107n, only the first schedule information field 1071 may include the end time indication field 1071-6 of the communication interval. On the other hand, the schedule information fields 1071, 1072, ..., 107n according to the third embodiment may not include the end time indication fields 1071-6, 1702-6, ..., 107n-6 of the communication section, In this case, the communication interval can be maintained until it is released by the SNVA-D frames 913 and 914. [ 9, the second station STA2 can release the communication interval by transmitting the SNAV-D frame 913, and other stations that have received the SNAV-D frame 913 can release the communication interval. The access point (AP) receiving the SNAV-D frame 913 can instruct the station corresponding to the hidden node to release the communication section by transmitting the SNAV-D frame 914.

Referring back to FIG. 9, the present invention will be described mainly on the SNAV-A frame according to the first embodiment, and the SNAV-A frame according to the second embodiment or the third embodiment will be described in the first embodiment The information of the exclusive section can be included in a manner similar to the SNAV-A frame according to FIG. The SNAV-A frame 901 may include a first schedule information field for the data frame 906, a second schedule information field for the data frame 912, and a third schedule information field for the data frame 915 have. The first schedule information field includes an interval field indicating the interval time of the exclusive section D1 in which channel occupation is required for receiving the data frame 906, May include a start time field of an exclusive section indicating a delay time S1 until the start time of the exclusive section D1. The second schedule information field includes an interval field indicating the interval time of the exclusive period D2 in which channel occupation is required for receiving the data frame 912, an ending point of the data frame 906 (or an SNAV-A frame 901) from the start time point of the exclusive period D2 to the start point of the exclusive period D2 indicated by the interval field. The third schedule information field includes an interval field indicating the interval time of the exclusive period D3 in which channel occupation is required for receiving the data frame 915, an ending point of the data frame 912 (or an SNAV-A frame 901) to the start time of the exclusive period D3 indicated by the interval field.

And the second station STA2 may transmit the SNAV-A frame 901. [ At this time, the second station STA2 may transmit the SNAV-A frame 901 to an access point (AP) connected thereto after the contention window according to the random backoff when the channel is idle during DIFS. Alternatively, the second station STA2 may transmit the SNAV-A frame 901 in a multicast or broadcast manner.

When receiving the SNAV-A frame 901, the access point AP can identify the SNAV-A frame 901 based on the transmitter address field and the dialogue token field, and the NAV for the section indicated by the schedule information field Can be set. In addition, the access point AP receives the SNAV-A frame 901 in response to the SNAV-A frame 901 in response to SIFS from the end of the SNAV-A frame 901, ACK frame) to the second station STA2. Alternatively, in response to the SNAV-A frame 901, the access point AP may transmit the SNAV-A frame 901 after the contention window due to the random backoff when the channel is idle after SIFS or DIFS from the end of the SNAV- -C (clear) frame 902 in multicast or broadcast manner. The SNAV-C frame 902 may be configured the same as the SNAV-A frame 901. For example, the dialog token field of the SNAV-C frame 902 may be set to the same value as the dialog token field of the SNAV-A frame 901. However, the action field included in the SNAV-C frame 902 may be set to binary number 01 to indicate that the current frame is the SNAV-C frame 902. The transmitter address field included in the SNAV-C frame 902 may be set to the MAC address of the access point (AP). The start time field of the exclusive section of the schedule information field included in the SNAV-C frame 902 indicates a section from the end time of the SNAV-C frame 902 to the start time of the exclusive section indicated by the corresponding interval field . In addition to the action field, the transmitter address field, and the schedule information field, the fields included in the SNAV-C frame 902 may include the same information as the fields included in the SNAV-A frame 901.

If the first station STA1 does not receive at least one of the SNAV-A frame 901 and the SNAV-C frame 902 or the first station STA1 receives the SNAV-A frame 901 and the SNAV- A frame 901 and SNAV-C frame 902), the first station STA1 receives the SNAV-A frame 901 and the SNAV-C frame 902 in accordance with the standard prior to the IEEE 802.11 standard defining the C frame 902 It can not be known that the exclusive section indicated by the -A frame 901 or the SNAV-C frame 902 is occupied by another station and frame transmission is restricted. The first station STA1 may transmit an RTS frame 903 to an access point (AP) when it has data to be transmitted to an access point (AP). An access point (AP) that receives the RTS frame 903 determines whether an interval indicated by the interval field included in the RTS frame 903 is within an exclusive interval indicated by the SNAV-A frame 901 or the SNAV- The guard frame 904 may be transmitted in order to prevent collision of frames in the overlapped section. At this time, the guard frame 904 may mean a self-CTS frame, and may mean a control frame, a management frame, or a data frame having an interval field for NAV setting. The interval field included in the guard frame 904 includes the start time field of the exclusive interval of the first schedule information field included in the SNAV-A frame 901 or the SNAV-C frame 902 from the end time of the guard frame 904 To indicate the time of the section within the start time point indicated by the start time point. The first station STA1 may abandon the current transmission opportunity associated with the RTS frame 903 upon receiving the guard frame 904 and may attempt to acquire a new transmission opportunity.

If an interval indicated by the interval field included in the RTS frame 903 does not overlap with the exclusive interval indicated by the SNAV-A frame 901 or the SNAV-C frame 902, A CTS frame 904 having interval information included in the CTS frame 903 can be transmitted. Even if the section indicated by the section field included in the RTS frame 903 overlaps with the exclusive section indicated by the SNAV-A frame 901 or the SNAV-C frame 902, And transmits the CTS frame 904 including the non-periodic information. When receiving the CTS frame 904, the first station STA1 may transmit the data frame to the access point (AP) when the data frame can be transmitted during the interval time indicated by the interval field included in the CTS frame 904 have. On the other hand, the first station STA1 does not transmit the data frame to the access point (AP) when the data frame can not be transmitted during the interval time indicated by the interval field included in the CTS frame 904.

On the other hand, if it follows that the standard prior to the IEEE 802.11 standard that defines the SNAV-A frame 901 and the SNAV-C frame 902 (i.e., fails to decode the SNAV-A frame 901 and the SNAV- ) For legacy stations, the access point (AP) initiates the start of the exclusive interval of the first schedule information field to prevent frame collision in the exclusive interval indicated by SNAV-A frame 901 or SNAV-C frame 902 The guard frame 905 may be transmitted in a preset interval (i.e., a buffer interval) before the starting point indicated by the view field. At this time, the guard frame 905 may mean a self-CTS frame, and may mean a control frame, a management frame, or a data frame having an interval field for NAV setting. The interval field of the guard frame 905 may indicate the interval time within the end point of the exclusive interval indicated by the interval field of the first schedule information field from the end of the guard frame 905. [ Each of the communication entities receiving the guard frame 905 can set the NAV based on the interval time indicated by the interval field included in the guard frame 905. [

The third station STA may transmit the data frame 906 to the second station STA2 in a Bluetooth manner. The second station STA2 can successfully receive the data frame 906 because no other communication entity transmits the frame in the transmission period (i.e., exclusive period) of the data frame 906 by the above-described method.

Thereafter, the first station STA1 may send an RTS frame 907 to the access point (AP) if it has data to transmit to the access point (AP). The access point AP receiving the RTS frame 907 receives the second schedule indicated by the interval field included in the RTS frame 907 in the SNAV-A frame 901 or the SNAV- The CTS frame 908, which is a response of the RTS frame 907, may be transmitted if it does not overlap with the exclusive period indicated by the interval field of the information field. The interval field included in the CTS frame 908 may indicate the interval time from the end point of the CTS frame 908 to the end point of the ACK frame 910. The first station STA1 may transmit the data frame 909 to the access point (AP) upon receiving the CTS frame 908. [ The access point AP may transmit an ACK frame 910, which is a response to the data frame 909, to the first station STA1 upon successful receipt of the data frame 909. [ The first station STA1 may determine that the data frame 909 has been successfully received at the access point (AP) when the ACK frame 910 is received.

On the other hand, in order to prevent frame collision in an exclusive period indicated by the second schedule information field included in the SNAV-A frame 901 or the SNAV-C frame 902, the access point (AP) The guard frame 911 can be transmitted in a predetermined interval (i.e., a buffer interval) before the start time point indicated by the start time field of the interval. At this time, the guard frame 911 may mean a self-CTS frame, and may mean a control frame, a management frame, or a data frame having an interval field for NAV setting. The interval field of the guard frame 911 may indicate the interval time within the end point of the exclusive interval indicated by the interval field of the second schedule information field from the end of the guard frame 911. [ Each of the communication entities receiving the guard frame 911 can set the NAV based on the interval time indicated by the interval field included in the guard frame 911. [

The third station STA may transmit the data frame 912 to the second station STA2 in a Bluetooth manner. The second station STA2 can successfully receive the data frame 912 because another communication entity does not transmit the frame in the transmission interval of the data frame 912 by the method described above.

Meanwhile, the second station STA2 may generate an SNAV-D (delete) frame 913 to cancel the NAV set based on the third schedule information field included in the SNAV-A frame 901. [ At least one of the control frame, the management frame and the data frame specified in IEEE 802.11 may be used as the SNAV-D frame 913, or a newly defined frame may be used. For example, the SNAV-D frame 913 comprises a MAC header 1010, a category field 1020, an action field 1030, a transmitter address field 1040, and a dialog token field 1050 shown in FIG. . The action field 1030 can indicate the type of the current frame. For example, if the action field 1030 is set to a binary number of 10, this may indicate that the current frame is the SNAV-D frame 913. The transmitter address field 1040 may be set to the MAC address of the communication entity transmitting the SNAV-D frame 913. Therefore, the transmitter address field of the SNAV-D frame 913 may be set to the MAC address of the second station STA2. The dialog token field 1050 may be set to the same value as the dialog token field of the SNAV-A frame 901 or SNAV-C frame 902. [ That is, the dialog token field 1050 may indicate that the NAV set based on the SNAV-A frame 901 or the SNAV-C frame 902 should be canceled.

And the second station STA2 may transmit the SNAV-D frame 913. [ At this time, the second station STA2 may transmit the SNAV-D frame 913 to an access point (AP) connected to the second station STA2 after the contention window according to the random backoff when the channel is idle during DIFS. Alternatively, the second station STA2 may transmit the SNAV-D frame 913 in a multicast or broadcast manner.

The access point AP determines that the NAV set on the basis of the SNAV-A frame 901 through the value set in the dialog token field of the SNAV-D frame 913 should be canceled when the SNAV-D frame 913 is received Able to know. Accordingly, the access point (AP) can cancel the NAV set based on the third schedule information field of the SNAV-A frame 901. [ In addition, the access point AP receives the SNAV-D frame 913 in response to the SNAV-D frame 913 in response to the SNAV-D frame 913, ACK frame) to the second station STA2. Alternatively, in response to the SNAV-D frame 913, the access point AP may send an SNAV-D frame 913 after the SNAV- -D frame 914 in a multicast or broadcast manner. The SNAV-D frame 914 may be configured the same as the SNAV-D frame 913. However, the transmitter address field included in the SNAV-D frame 914 may be set to the MAC address of the access point (AP). In addition to the transmitter address field, the field included in the SNAV-D frame 914 may include the same information as the field included in the SNAV-D frame 913. [ The first station STA1 receives the SNAV-A frame 901 or the SNAV-C frame 902 via the value set in the dialog token field of the SNAV-D frame 914 when receiving the SNAV- Based NAV should be canceled. Thus, the access point (AP) can cancel the NAV established based on the third schedule information field of the SNAV-A frame 901 or the SNAV-C frame 902. [

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

Claims (20)

A communication method performed at a first station,
Generating a first frame including information of an exclusive period for transmission or reception of a data frame; And
And transmitting the first frame,
Wherein the exclusive section has a transmission interval and a transmission interval of the first frame, and communication of stations other than the first station in the interval is allowed. The method according to claim 1,
The first frame includes a schedule information field, and the schedule information field indicates a start time point of the exclusive period indicated by the interval field and an interval field indicating a time interval of the exclusive period And a start time field. The method according to claim 1,
Wherein the first frame includes a schedule information field, the schedule information field including a start time field indicating a start time of the exclusive section and an end time field indicating an end time of the exclusive section. The method according to claim 1,
Wherein the first frame includes a schedule information field, wherein the schedule information field includes a start time field indicating a start time point of a communication interval including the monopolistic interval and a period in which communication of a station other than the first station is allowed, An end point indication field including an interval field indicating the interval time of the exclusive section, an interval field indicating the interval time between the exclusive intervals, and an information indicating the end time of the communication interval. The method according to claim 1,
The communication method includes:
Further comprising receiving a response frame from an associated access point of the first station in response to the first frame. The method according to claim 1,
The communication method includes:
Further comprising obtaining a second frame from the access point to which the first station is connected, the second frame including information of the exclusive period. The method according to claim 1,
The communication method includes:
Further comprising receiving a data frame from a second station in a reception interval indicated by the information of the exclusive section. The method according to claim 1,
The communication method includes:
And transmitting a data frame to a second station in a transmission interval indicated by the information of the exclusive section. The method according to claim 1,
Wherein the first frame includes information of a plurality of exclusive periods indicating different transmission intervals or reception intervals. The method according to claim 1,
Wherein the first frame is transmitted based on a first communication protocol and the data frame is transmitted or received based on a second communication protocol. The method according to claim 1,
Wherein the first station supports a plurality of communication protocols. A communication method performed at a first station,
Receiving a first frame from a second station, the first frame including information of a monopoly section for transmission or reception of a data frame; And
And transmitting a second frame in response to the first frame,
Wherein the exclusive period has a transmission interval and a transmission interval of the first frame, and communication of stations other than the second station in the interval is allowed. The method of claim 12,
Wherein the first frame includes a schedule information field, wherein the schedule information field indicates a start time point of the exclusive period indicated by the interval field and a duration field indicating a duration time of the exclusive period And a start time field. The method of claim 12,
And the second frame is a response frame. The method of claim 12,
And the second frame includes information of the exclusive period. The method of claim 12,
The communication method includes:
Receiving a request to send (RTS) frame from a third station; And
If an interval indicated by the interval field included in the RTS frame is overlapped with an exclusive interval indicated by the interval field included in the first frame, a guard frame is transmitted to prevent collision of frames in the overlapped interval Further comprising the steps of: 18. The method of claim 16,
Wherein an interval field of the guard frame indicates an interval time within a start time of the exclusive section from an end time of the guard frame. The method of claim 12,
The communication method includes:
Further comprising the step of transmitting a guard frame at a predetermined interval before the start time of the exclusive period to prevent collision of the frame in the exclusive period. 19. The method of claim 18,
And the duration field of the guard frame indicates a duration time from an ending point of the CTS frame to an ending point of the exclusive section. The method of claim 12,
Wherein the first frame is transmitted based on a first communication protocol and the data frame is transmitted or received based on a second communication protocol.

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