WO2017023005A1 - Channel bonding based signal transmission method and device therefor - Google Patents

Abstract

The present specification relates to a method by which an access point (AP) transmits a signal in a wireless LAN (WLAN) system, and a device therefor. To this end, the access point (AP) allocates M number of channels to a first station (STA) and N number of channels to a second STA so as to transmit a signal, wherein, when two or more channels are allocated to the first STA and/or the second STA, the AP transmits the signal to the first STA and/or the second STA through channel bonding or channel aggregation, and when there is an overlapped first channel among the M number of channels and the N number of channels, a signal transmitted to the first STA from the first channel and a signal transmitted to the second STA from the first channel can be distinguished from each other through precoding applied to the respective signals.

Description

Channel bonding based signal transmission method and apparatus therefor

The following description relates to channel bonding in a mobile communication system, and more particularly, to a method and apparatus for transmitting a signal based on channel bonding in an access point or station in a WLAN system. .

The standard for WLAN technology is being developed as an Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard. IEEE 802.11a and b are described in 2.4. Using unlicensed band at GHz or 5 GHz, IEEE 802.11b provides a transmission rate of 11 Mbps and IEEE 802.11a provides a transmission rate of 54 Mbps. IEEE 802.11g applies orthogonal frequency-division multiplexing (OFDM) at 2.4 GHz to provide a transmission rate of 54 Mbps. IEEE 802.11n applies multiple input multiple output OFDM (MIMO-OFDM) to provide a transmission rate of 300 Mbps for four spatial streams. IEEE 802.11n supports channel bandwidths up to 40 MHz, in this case providing a transmission rate of 600 Mbps.

The WLAN standard uses a maximum of 160MHz bandwidth, supports eight spatial streams, and supports IEEE 802.11ax standard through an IEEE 802.11ac standard supporting a speed of up to 1Gbit / s.

Meanwhile, IEEE 802.11ad defines performance enhancement for ultra-high throughput in the 60 GHz band, and IEEE 802.11ay for channel bonding and MIMO technology is introduced for the first time in the IEEE 802.11ad system.

While data transmission based on channel bonding can provide high throughput, this may require a new Physical Protocol Data Unit (PPDU) format.

In particular, when a signal is transmitted through channel bonding or channel aggregation by applying multi-user (MU) -multi input multi output (MIMO) technology, signals transmitted and received to each STA may be different from each other. How to distinguish from these may be required.

For the IEEE 802.11ay standardization as described above, a study on a new PPDU format considering a compatibility with an existing legacy system (eg, 11ad STA), and a method and apparatus for transmitting the same is required.

According to an aspect of the present invention for solving the above problems, in a method in which an access point (AP) transmits a signal in a WLAN system, the AP provides M channels to the first station STA. And transmits a signal by allocating M channels to a second STA, and when two or more channels are allocated to at least one of the first STA and the second STA, the AP is configured to perform the first STA and the first STA. In the first channel, when a signal is transmitted to at least one of 2 STAs through channel bonding or channel aggregation, and there is a duplicated first channel among the M channels and the N channels, The signal transmitted to the first STA and the signal transmitted to the second STA are distinguished from each other through precoding applied to each signal. At this time, M, N is a natural number is applied.

Precoding for multi-stream transmission to the first STA and the second STA is applied to the first channel, and a signal only to the first STA is applied to a second channel that does not overlap the N channels among the M channels. Precoding for transmission may be applied.

The bandwidth of one channel may be 1.83 GHz.

The maximum value of M and N may be 4 applied. However, the maximum value may vary in the standardization process, and the present invention is not limited to a specific numerical value.

When the values of M and N are different from each other, a guard tone is applied to a subcarrier adjacent to a subcarrier used for signal transmission to the second STA among subcarriers used for signal transmission to the first STA. Can be used as)

When the M value is 2 or more, a total bandwidth of M channels used for signal transmission to the first STA may be greater than N times the bandwidth of one channel.

The signal transmitted by the AP to the first STA may include one or more of bandwidth information and channelization information allocated to the first STA.

In particular, the signal transmitted by the AP to the first STA may further include group identification information.

In addition, one or more of bandwidth information and channelization information allocated to the first STA may be included in a header for a first type STA or a header for a second type STA of a signal transmitted to the first STA.

In addition, one or more of bandwidth information and channelization information allocated to the first STA may be indicated by one or more bit indicators.

For example, at least one of bandwidth information and channelization information allocated to the first STA is indicated by as many bit indicators as the maximum number of channels supported by the system, and each bit indicator indicates that a channel corresponding to each bit indicator is assigned to the first indicator. 1 may indicate whether the STA is allocated in an on / off manner.

Meanwhile, according to another embodiment of the present invention, in a method in which a first station (STA) transmits a signal to an access point (AP) in a WLAN system, the first STA has two or more channels from the AP. The first STA transmits a signal to the AP through the allocated channel, but there is a duplicated first channel among the channel allocated to the first STA and the channel allocated to the second STA, The present invention proposes a signal transmission method in which a signal transmitted by the first STA and a signal transmitted by the second STA are distinguished from each other through precoding applied to each signal in a first channel.

Meanwhile, according to another embodiment of the present invention, in an access point apparatus that transmits a signal in a WLAN system, M channels are allocated to a first station (STA), and N channels are assigned to a second STA. An allocating processor; And a transceiver connected to the processor and configured to transmit a signal to the first STA and the second STA, respectively, when two or more channels are allocated to one or more of the first STA and the second STA. An AP transmits a signal to at least one of the first STA and the second STA through channel bonding or channel aggregation, and a first channel overlapping among the M channels and the N channels. In this case, the signal transmitted to the first STA and the signal transmitted to the second STA in the first channel are configured to be distinguished from each other through precoding applied to each signal. At this time, M, N is a natural number is applied.

On the other hand, in another embodiment of the present invention, a station (STA) for transmitting signals in a WLAN system, the transceiver comprising: a transceiver configured to transmit a signal; And a processor controlling the transceiver, wherein the processor receives two or more channels from an access point, and the processor controls the transceiver to transmit a signal through the allocated channel to the AP. When there is a overlapping first channel among a channel allocated to the first STA and a channel allocated to the second STA, a signal transmitted by the first STA and a signal transmitted by the second STA in each of the first channels are each A station apparatus is proposed, which is configured to be distinguished from each other through precoding applied to a signal.

The present invention supports DL (Downlink) MU-MIMO in the 11ay system and when the access point (AP) transmits a signal to the first station (STA) through channel bonding or channel aggregation, It is possible to provide a method of distinguishing a signal transmitted to the first STA from other signals.

Furthermore, the present invention has the effect of improving system performance in a dense environment under consideration in the IEEE 802.11ay system.

The effects obtainable in the present invention are not limited to the above-mentioned effects, and other effects not mentioned above may be clearly understood by those skilled in the art from the following description. will be.

BRIEF DESCRIPTION OF THE DRAWINGS The drawings appended hereto are for the purpose of providing an understanding of the present invention and for illustrating various embodiments of the present invention and for describing the principles of the present invention in conjunction with the description thereof.

1 is a diagram illustrating an example of a configuration of a WLAN system.

2 is a diagram illustrating another example of a configuration of a WLAN system.

3 is a diagram for describing a channel in a 60 GHz band for explaining a channel bonding operation according to an embodiment of the present invention.

4 is a diagram illustrating a basic method of performing channel bonding in a WLAN system.

5 is a diagram for explaining a physical configuration of an existing radio frame.

6 and 7 are views for explaining the configuration of the header field of the radio frame of FIG.

8 illustrates a PPDU structure applicable to the present invention.

9 and 10 are diagrams illustrating operating frequency bands used by a plurality of stations STA in accordance with the present invention.

11 illustrates a PPDU structure according to an embodiment of the present invention.

12 is a view for explaining an apparatus for implementing the method as described above.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. The detailed description, which will be given below with reference to the accompanying drawings, is intended to explain exemplary embodiments of the present invention and is not intended to represent the only embodiments in which the present invention may be practiced.

The following detailed description includes specific details in order to provide a thorough understanding of the present invention. However, one of ordinary skill in the art appreciates that the present invention may be practiced without these specific details. In some instances, well-known structures and devices are omitted or shown in block diagram form, centering on the core functions of each structure and device, in order to avoid obscuring the concepts of the present invention.

As described above, the following description relates to a method and apparatus for transmitting data based on channel bonding in a mobile communication system. There may be various mobile communication systems to which the present invention is applied. Hereinafter, the WLAN system will be described in detail as an example of the mobile communication system.

1 is a diagram illustrating an example of a configuration of a WLAN system.

As shown in FIG. 1, the WLAN system includes one or more basic service sets (BSSs). A BSS is a set of stations (STAs) that can successfully synchronize and communicate with each other.

An STA is a logical entity that includes a medium access control (MAC) and a physical layer interface to a wireless medium. The STA is an access point (AP) and a non-AP STA (Non-AP Station). Include. The portable terminal operated by the user among the STAs is a non-AP STA, and when referred to simply as an STA, it may also refer to a non-AP STA. A non-AP STA is a terminal, a wireless transmit / receive unit (WTRU), a user equipment (UE), a mobile station (MS), a mobile terminal, or a mobile subscriber. It may also be called another name such as a mobile subscriber unit.

The AP is an entity that provides an associated station (STA) coupled to the AP to access a distribution system (DS) through a wireless medium. The AP may be called a centralized controller, a base station (BS), a Node-B, a base transceiver system (BTS), a personal basic service set central point / access point (PCP / AP), or a site controller.

BSS can be divided into infrastructure BSS and Independent BSS (IBSS).

The BBS shown in FIG. 1 is an IBSS. The IBSS means a BSS that does not include an AP. Since the IBSS does not include an AP, access to the DS is not allowed, thereby forming a self-contained network.

2 is a diagram illustrating another example of a configuration of a WLAN system.

The BSS shown in FIG. 2 is an infrastructure BSS. Infrastructure BSS includes one or more STAs and APs. In the infrastructure BSS, communication between non-AP STAs is performed via an AP. However, when a direct link is established between non-AP STAs, direct communication between non-AP STAs is also possible.

As shown in FIG. 2, a plurality of infrastructure BSSs may be interconnected through a DS. A plurality of BSSs connected through a DS is called an extended service set (ESS). STAs included in the ESS may communicate with each other, and a non-AP STA may move from one BSS to another BSS while seamlessly communicating within the same ESS.

The DS is a mechanism for connecting a plurality of APs. The DS is not necessarily a network, and there is no limitation on the form if it can provide a predetermined distribution service. For example, the DS may be a wireless network such as a mesh network or a physical structure that connects APs to each other.

Based on the above, the channel bonding method in the WLAN system will be described.

3 is a diagram for describing a channel in a 60 GHz band for explaining a channel bonding operation according to an embodiment of the present invention.

As shown in FIG. 3, four channels may be configured in the 60 GHz band, and a general channel bandwidth may be 2.16 GHz. The ISM bands available from 60 GHz (57 GHz to 66 GHz) may be defined differently in different countries. In general, channel 2 of the channels shown in FIG. 3 may be used in all regions and may be used as a default channel. Channels 2 and 3 can be used in most of the designations except Australia, which can be used for channel bonding. However, a channel used for channel bonding may vary, and the present invention is not limited to a specific channel.

4 is a diagram illustrating a basic method of performing channel bonding in a WLAN system.

The example of FIG. 4 illustrates the operation of 40 MHz channel bonding by combining two 20 MHz channels in an IEEE 802.11n system. For IEEE 802.11ac systems, 40/80/160 MHz channel bonding will be possible.

The two exemplary channels of FIG. 4 include a primary channel and a secondary channel, so that the STA can examine the channel state in a CSMA / CA manner for the primary channel of the two channels. If the secondary channel is idle for a predetermined time (e.g. PIFS) at the time when the primary channel idles for a constant backoff interval and the backoff count becomes zero, the STA is assigned to the primary channel and Auxiliary channels can be combined to transmit data.

However, when channel bonding is performed based on contention as illustrated in FIG. 4, channel bonding may be performed only when the auxiliary channel is idle for a predetermined time at the time when the backoff count for the primary channel expires. Therefore, the use of channel bonding is very limited, and it is difficult to flexibly respond to the media situation.

Accordingly, an aspect of the present invention proposes a method in which an AP transmits scheduling information to STAs to perform access on a scheduling basis. Meanwhile, another aspect of the present invention proposes a method of performing channel access based on the above-described scheduling or on a contention-based basis independently of the above-described scheduling. In addition, another aspect of the present invention proposes a method for performing communication through a spatial sharing technique based on beamforming.

Hereinafter, the physical layer configuration in the WLAN system to which the present invention is applied will be described in detail.

In the WLAN system according to an embodiment of the present invention, it is assumed that three different modulation modes may be provided.

Hereinafter, the physical layer configuration in the WLAN system to which the present invention is applied will be described in detail.

In the WLAN system according to an embodiment of the present invention, it is assumed that three different modulation modes may be provided.

PHY	MCS	anmerkung
Control PHY	0
Single carrier PHY (SC PHY)	1 ... 1225 ... 31	(low power SC PHY)
OFDM PHY	13 ... 24

Such modulation modes can be used to meet different requirements (eg, high throughput or stability). Depending on your system, only some of these modes may be supported.

5 is a diagram for explaining a physical configuration of an existing radio frame.

It is assumed that all DMG (Directional Multi-Gigabit) physical layers commonly include fields as shown in FIG. 5. However, there may be a difference in the method of defining individual fields and the modulation / coding method used according to each mode.

As shown in FIG. 5, the preamble of the radio frame may include a Short Training Field (STF) and a Channel Estimation (CE). In addition, the radio frame may include a header and a data field as payload and optionally a TRN field for beamforming.

6 and 7 are views for explaining the configuration of the header field of the radio frame of FIG.

Specifically, FIG. 6 illustrates a case where the SC mode is used. In SC mode, the header includes information indicating the initial value of scrambling, Modulation and Coding Scheme (MCS), information indicating the length of data, information indicating whether an additional physical protocol data unit (PPDU) exists, packet type, training length, and aggregation. It may include information about whether to request a beam planeing request, a final received signal strength indicator (RSSI), a truncation state, a header check sequence (HCS), and the like. In addition, as shown in FIG. 6, the header has 4 bits of reserved bits, which may be used in the following description.

7 shows a specific configuration of a header when the OFDM mode is applied. The OFDM header includes information indicating the initial value of scrambling, MCS, information indicating the length of data, information indicating the presence or absence of additional PPDUs, packet type, training length, aggregation, beam beaming request, last RSSI, truncation, Information such as a header check sequence (HCS) may be included. In addition, as shown in FIG. 7, the header has 2 bits of reserved bits, and in the following description, such reserved bits may be utilized as in the case of FIG. 6.

As described above, the IEEE 802.11ay system is considering introducing channel bonding and MIMO technology for the first time in the existing 11ad system. To implement channel bonding and MIMO in 11ay, a new PPDU structure is needed. That is, the existing 11ad PPDU structure has limitations in supporting legacy terminals and implementing channel bonding and MIMO.

To this end, a new field for the 11ay terminal may be defined after the legacy preamble and the legacy header field for supporting the legacy terminal. Here, channel bonding and MIMO may be supported through the newly defined field.

8 illustrates a PPDU structure applicable to the present invention. In FIG. 8, the horizontal axis may correspond to the time domain and the vertical axis may correspond to the frequency domain.

When two or more channels are bonded, a frequency band (eg, 400 MHz band) of a predetermined size may exist between frequency bands (eg, 1.83 GHz) used in each channel. In the mixed mode, legacy preambles (legacy STFs, legacy: CEs) are transmitted as duplicates through each channel. In an embodiment of the present invention, a new STF and a legacy ST can be simultaneously transmitted through a 400 MHz band between each channel. Gap filling of the CE field may be considered.

In this case, as shown in FIG. 8, the PPDU structure according to the present invention transmits ay STF, ay CE, ay header B, and payload in a broadband manner after legacy preamble, legacy header, and ay header A. Has a form. Therefore, the ay header, ay Payload field, etc. transmitted after the legacy header field may be transmitted through channels used for bonding. Hereinafter, the ay header may be referred to as an enhanced directional multi-gigabit (EDMG) header to distinguish the ay header from the legacy header, and the name may be used interchangeably.

For example, since 11ay has a total of four channels (each 2.16 GHz), the ay header and the ay payload may be transmitted through 2.16 GHz, 4.32 GHz, 6.48 GHz, and 8.64 GHz bandwidth.

Alternatively, the PPDU format when repeatedly transmitting the legacy preamble without performing the gap-filling as described above may also be considered.

In this case, ay STF, ay CE, and ay header B are replaced by a legacy preamble, legacy header, and ay header A without a GF-Filling and thus without the GF-STF and GF-CE fields shown by dotted lines in FIG. 8. It has a form of transmission.

Based on the above, in the present invention, when the 11ay system supports downlink (MU) multi-user (MU) MIMO, an access point (AP) provides a predetermined number of channels to a plurality of stations (STA), respectively. The present invention proposes a method of allocating a signal or data to be transmitted and received, and distinguishing signals transmitted to different STAs from some overlapping channels allocated to a plurality of STAs. This can improve system performance in the dense environment under consideration in IEEE 802.11ay systems.

When there are several STAs having different channel bonding capabilities in an arbitrary BSS, a transmitting end of an access point (AP) simultaneously uses a plurality of antennas to transmit a plurality of STAs to different STAs through various bandwidths for each STA at the same time. It can transmit data or signals.

-STAs capable of 4-channel bonding transmit data by bonding up to 4 channels

-STAs capable of 3-channel bonding transmit data by bonding up to 3 channels

-STAs capable of 2-channel bonding transmit data by bonding up to 2 channels

-STA transmits data through one channel to the STA that cannot be channel bonded

However, the above example assumes that the total number of available channels is four channels, and if the total number of available channels exceeds four channels, at least one to the maximum number of available total channels depending on the capability of the STA. By bonding as much as possible can transmit and receive data.

Accordingly, in a preferred embodiment of the present invention, when several STAs overlap some frequency resources or channels, signals transmitted to each STA in the overlapped frequency resources or channels are distinguished from each other through precoding for each signal. Suggest to be.

FIG. 9 illustrates an operating frequency band or bandwidth used by a plurality of STAs when no guard tone is used according to an embodiment of the present invention, and FIG. 10 illustrates another embodiment of the present invention. In the case of using the guard tone, a diagram showing an operating frequency band or bandwidth used by a plurality of STAs.

In the present invention, each STA has an operating frequency band in units of channels. Accordingly, the first STA of FIGS. 9 and 10 may use one channel, and the second STA may bond two channels. In this case, the channel unit may be differently applied according to a value adopted in the 11ay standard. For example, 1.83 GHz may be applied. Alternatively, 1760 MHz may be applied.

A transmitting end of an access point (AP) according to the present invention precodes subcarriers on a subcarrier basis for subcarriers used to simultaneously transmit different data to multiple STAs among fast subcarriers of the size of a fast fourier transform (FFT). By applying to support multiple STAs simultaneously, subcarriers used to transmit data to a single STA also supports a single STA by applying precoding.

For example, in FIG. 9 and FIG. 10, one channel is allocated as a frequency resource to the first STA, two channels are allocated as frequency resources to the second STA, and some frequency resources allocated to the second STA are assigned to the first STA. It overlaps with the frequency resource allocated to. In this case, precoding for multi-stream transmission is applied to the first STA and the second STA to one channel superimposed on both STAs, and precoding that can transmit data only to the second STA to the other one of the two channels. This applies.

In other words, in the overlapped channel, data signals transmitted to each STA may be precoded so that data signals transmitted to the first STA and data signals transmitted to the second STA may be distinguished from each other through precoding. do.

For example, a data signal transmitted to the first STA and a data signal transmitted to the second STA in the overlapped operating channel may be orthogonal or pseudo-orthogonal through precoding applied to each signal. In the present invention, various modifications in which both signals other than the above embodiments are divided by precoding may also be applied.

In FIGS. 9 and 10, only two channels are bonded, but the number of channels used for bonding may be extended by four or the maximum number of channels provided by the system.

As shown in FIG. 9, if a separate guard tone is not applied, the first STA may receive data using one channel of 1.83 GHz bandwidth, and the second STA may have two channels. Data may be received using the bonded 3.99 GHz bandwidth. In this case, a total bandwidth usable by the second STA may be greater than twice the size of the total bandwidth usable by the first STA.

Alternatively, the guard tone may be applied as shown in FIG. 10. When the guard tone is used as described above, interference generated from adjacent subcarriers may be removed or reduced. In the case of using the guard tone, a method of allocating the guard tone when the total number of STAs participating in the MU-MIMO is n can be expressed as follows.

1. The adjacent subcarrier of Min (BW_1, BW_2, ..., BW_n) is used as the guard tone. (Each BW is not the same.)

2. Except for BW_i obtained in step 1, get the Min value of step 1 again.

3. The adjacent subcarrier of BW_j obtained in step 2 is used as the guard tone.

4. Repeat steps 1 through 3 n-1.

(BW_k: kth bandwidth among bandwidths allocated to STA)

When the guard tone is used using the above method, the subcarrier between the two channels cannot be used for data transmission as shown in FIG. 10, and thus, the first STA can receive data using the 1.83 GHZ bandwidth and the second STA. The STA may receive data using a 3.66 GHz bandwidth that is twice the operating bandwidth of the first STA.

As described above, in order to transmit data to a plurality of STAs, an AP may allocate a channel or bandwidth to be used for data transmission for each STA, and the AP may allocate a channel or bandwidth allocated for each STA using a specific field value of the PPDU format. Information may be signaled to each STA.

As an example applicable to the present invention, the AP may signal a channel or bandwidth used for each STA through the EDMG header A of the PPDU format when transmitting data to the STA. The EDMG header A informs the channel or bandwidth used for data transmission for each STA so that each STA needs to receive only the corresponding channel or bandwidth. In the above case, in order to reduce overhead, there is no need to have a field indicating the same bandwidth to all STAs in EDMG header A in non-MIMO and single-user (SU) -MIMO.

In addition, each STA is pre-assigned group identification information (eg, Group ID) and an index within the corresponding Group ID. Therefore, if the group identification information is included in the EDMG header A in the signal sent from the transmitting end of the AP, each STA checks whether the group belongs to the group ID in the EDMG header A, and if the group is correct, matches the previously given index. You can check the number of streams and the channel or bandwidth according to the fields.

Such a signaling method is a method of dynamically adjusting / allocating a channel or bandwidth for each STA (hereinafter, referred to as a dynamic channel allocation method) and a method of statically allocating the same channel or bandwidth to all STAs (hereinafter, referred to as a static channel assignment method). Can be applied to all. In this case, the transmitting end of the AP may signal whether one of the two channel allocation methods is selected / applied through the 1-bit indicator of the EDMG header A. (0: Static MU-MIMO, 1: dynamic MU-MIMO)

In another embodiment of the present invention, the signaling information for the channel or bandwidth used for each STA is the RTS (ready-to-send) / CTS (STA) of the STA and PCP / AP before the STA receives data other than the EDMG header A clear-to-send) Reporting can also be made through send / receive. For example, in reporting through an RTS / CTS frame, the PCP / AP and STAs may inform the transceiver by modifying reserved bits (2 to 3 bits) of a header in the RTS / CTS PPDU format. have. Or, it may be informed using reserved bits of the RTS / CTS Mac Protocol Data Unit (MPDU).

Alternatively, the reserved bits of the legacy field are modified (in the case of the 11ad SC PHY, the reserved bits of the legacy header field exist in total of 4 bits, and in the case of the 11ad OFDM PHY, there are 2 bits). Can provide. This description assumes that channel bonding assumes continuous aggregation between channels, but need not be limited thereto.

Hereinafter, Tables 2 to 7 disclose methods of informing channel bonding information used for data transmission individually to STAs participating in data reception through EDMG header A or other field values of the above-described PPDU format. . Here, the number of STAs can be extended to other STAs.

Field name	Number of bits	Description
BW (bandwidth)	2	0: 2.15 GHz (signle channel) 1: 4.32 GHz (2 channel bonding) 2: 6.48 GHz (3 channel bonding) 3: 8.64 GHz (4 channel bonding)

Field name	Number of bits	Description
CH (channel)	3	0: signle channel 1: 2 channel bonding (ch1, ch2) 2: 2 channel bonding (ch2, ch3) 3: 2 channel bonding (ch3, ch4) 4: 3 channel bonding (ch1, ch2, ch3) 5: 3 channel bonding (ch2, ch3, ch4) 6: 4 channel bonding (ch1, ch2, ch3, ch4) 7: reserved

Field name	Number of bits	Description
BW (bandwidth) or CH (channel)	4	1st bit: Use CH 1 (1: On, 0: Off) 2nd bit: Use CH 2 (1: On, 0: Off) 3rd bit: Use CH 3 (1: On, 4th bit: Whether CH 4 is used (1: On, 0: Off)

Meanwhile, an embodiment of the present invention provides a method of transmitting a frame using a plurality of channels by a channel aggregation method as a sub-concept of the above-described channel bonding or separate from the channel bonding. In the case of channel combining, the FFT size of the plurality of channels may be kept the same, and the information transmitted on each channel may be combined and used. In this case, four channels can be used more flexibly, and each channel can be turned on or off in a bitmap manner through EDMG header A or other field values of the above-described PPDU format to support such channel bonding / channel combining. You can tell as shown in Table 4.

For example, when the bit value of the EDMG header A is 1100, it may indicate that channel 1 and channel 2 are used by channel bonding, and in case of 1010, it may indicate that channel 1 and channel 3 are used by channel combining.

In addition, Table 4 shows a case in which the maximum number of channels applied to the 11ay system is four, and the configuration may be extended to the number of bits corresponding to the maximum number of channels applied to the actual system. In this case, each bit indicator may indicate whether a channel corresponding to each bit indicator is allocated to a specific STA in an on / off manner.

In another embodiment, the channel of the 11ay system may consist of a primary channel and a secondary channel. The primary channel is determined during the initial association process. Auxiliary channel refers to the remaining channels other than the primary channel. Accordingly, the remaining channels other than the main channel among CH1, CH2, CH3, and CH4 defined in 11ad may be auxiliary channels. In this case, signaling information indicating a channel or bandwidth used by each STA included in the EDMG header A field or the legacy field of the PPDU format may be represented as shown in Tables 5 to 7.

Field name	Number of bits	Description
BW (bandwidth) or CH (channel)	2	0: primary channel 1: 2 channel bonding (primary channel + secondary channel 1) 2: 3: channel bonding (primary channel + secondary channel 1,2) 3: 4 channel bonding (primary channel + secondary channel 1,2,3)

Field name	Number of bits	Description
BW (bandwidth) or CH (channel)	3	0: primary channel 1: 2 channel bonding (primary channel + secondary channel 1) 2: 2 channel bonding (primary channel + secondary channel 2) 3: 2 channel bonding (primary channel + secondary channel 3) 4: 3 channel bonding (primary channel + secondary channels 1,2) 5: 3 channel bonding (primary channel + secondary channels 1,3) 6: 3 channel bonding (primary channel + secondary channels 2,3) 7: 4 channel bonding (primary channel + secondary channels 1, 2,3)

Field name	Number of bits	Description
BW (bandwidth) or CH (channel)	4	1st bit: Whether primary channel is used (1: On, 0: Off) 2nd bit: Whether secondary channel 1 is used (1: On, 0: Off) 3rd bit: Whether secondary channel 2 is used (1: 4th bit: Whether secondary channel 3 is used (1: On, 0: Off)

Through the signaling method as described above, the AP may provide channel information allocated to each STA to a plurality of STAs. In this case, the following schemes may be applied to the channel allocation scheme for each STA.

<Dynamic Channel Allocation Method>

As a dynamic allocation method in which a channel or bandwidth allocated to each STA is dynamically changed, the following two methods may be considered.

a. When allocating a channel or bandwidth to all the STAs participating in the reception individually, all the STAs share a single primary channel.

b. When allocating bandwidth to all STAs participating in the reception individually, all STAs are independently allocated a channel.

In particular, in the case of a, as described above, the channel or bandwidth information allocated to each STA may be known through the EDMG header A of the PPDU format, but if the primary channel access method such as 802.11ac is applied, all STAs participating in the reception Since carrier sensing is performed through the primary channel, the allocated bandwidth can be known by receiving the preamble and the header transmitted from the transmitting end of the AP.

FIG. 11 illustrates a PPDU structure according to an embodiment of the present invention. As shown in FIG. 9 or FIG. 10, a first STA receives data through one channel, and a second STA uses two channel bonding. Receives data, but indicates a PPDU format when some operating channels overlap with an operating channel of the first STA.

As shown in FIG. 11, the first STA and the second STA receive data by sharing a primary channel, and the number or bandwidth of channels available for receiving each data by various STAs may vary in various sizes. Scalable (up to the maximum number of channels).

Although FIG. 11 illustrates a PPDU format transmitted to a first STA and a second STA based on the PPDU format of FIG. 8, in another embodiment of the present invention, a structure different from the legacy STF field to the EDMG header A field in the PPDU format is illustrated in FIG. May be sent to. For example, the first STA receives data only through one channel (primary channel, CH1). As a PPDU format transmitted to the first STA, legacy STF, legacy CE, and legacy are used only through one channel (CH1). The PPDU format in which the header and the EDMG header A are transmitted may be applied.

<Static Channel Allocation Method>

In the static channel allocation scheme, all STAs participating in MU-MIMO bond the same channels or receive data through the same single channel. That is, the frequency resources used by all STAs for data reception are the same.

When the static channel allocation scheme is applied, all channel or bandwidth information signaled to each STA may be equally applied through the EDMG header A field or the other field of the PPDU format of the present invention.

In this embodiment, when channel bonding is performed, the reserved bits (OFDM PHY: 2 bits and SC PHY: 4 bits) of the legacy headers are modified to consider that ay headers are not duplicated and transmitted, but may also transmit different data. .

The PPDU format when signaling for channel bonding is performed through the legacy header is shown in FIG. 11. 1 is a PPDU format when two-channel bonding is performed and can be expanded to three-channel and four-channel bonding.

In order to transmit data in the PPDU format as shown in FIG. 8, it is preferable to sense a frequency band used for channel bonding in Rx. The legacy preamble is received through each channel used for channel bonding, and AGC, synchronization, and channel estimation are separately performed. Therefore, different information can be sent to ay header A and ay header B.

Modulation of the ay header is possible for both SC PHY and OFDM PHY. In case of SC PHY, the chip rate can be transmitted and received in wide band by x2, x3, and x4 times proportional to the number of channels used for channel bonding.In the case of OFDM PHY, the sampling rate and FFT size of the channel used for channel bonding It can transmit / receive wide band by x2, x3, x4 times in proportion to the number. In the OFDM PHY, it is preferable to insert and transmit a null value in a subcarrier matching a 400 MHz band between channels.

In another embodiment of the present invention, the AP may provide spatial stream number information by modifying some field values such as an EDMG header A or EDMG header B field of the PPDU. As an example, a maximum of 2 bits may be applied to the number of bits for providing the information, thereby providing up to four spatial stream number information to the STA.

In another embodiment, the present invention can also be applied to an uplink operation in which an STA transmits a signal to an AP.

More specifically, in a method in which a first STA transmits a signal to an AP in a WLAN system according to another embodiment of the present invention, the first STA is allocated two or more channels from the AP, When the first STA transmits a signal to the AP through the allocated channel, and there is a duplicated first channel among the channel allocated to the first STA and the channel allocated to the second STA, The signal transmitted by the first STA and the signal transmitted by the second STA may be distinguished from each other through precoding applied to each signal.

12 is a view for explaining an apparatus for implementing the method as described above.

The wireless device 800 of FIG. 12 may correspond to a specific STA of the above description, and the wireless device 850 may correspond to the PCP / AP of the above-described description.

The STA 800 may include a processor 810, a memory 820, and a transceiver 830, and the PCP / AP 850 may include a processor 860, a memory 870, and a transceiver 880. can do. The transceiver 830 and 880 may transmit / receive a radio signal and may be executed in a physical layer such as IEEE 802.11 / 3GPP. The processors 810 and 860 are executed at the physical layer and / or MAC layer, and are connected to the transceivers 830 and 880. Processors 810 and 860 may perform the aforementioned UL MU scheduling procedure.

Processors 810 and 860 and / or transceivers 830 and 880 may include application-specific integrated circuits (ASICs), other chipsets, logic circuits and / or data processors. The memories 820 and 870 may include read-only memory (ROM), random access memory (RAM), flash memory, memory cards, storage media and / or other storage units. When an embodiment is executed by software, the method described above can be executed as a module (eg, process, function) that performs the functions described above. The module may be stored in the memory 820, 870 and executed by the processors 810, 860. The memories 820 and 870 may be disposed inside or outside the processes 810 and 860 and may be connected to the processes 810 and 860 by well-known means.

The detailed description of the preferred embodiments of the invention disclosed as described above is provided to enable any person skilled in the art to make and practice the invention. Although the above has been described with reference to a preferred embodiment of the present invention, those skilled in the art will understand that the present invention can be variously modified and changed from the above description. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

As described above, the present invention has been described assuming that it is applied to an IEEE 802.11-based WLAN system, but the present invention is not limited thereto. The present invention can be applied in the same manner to various wireless systems capable of data transmission based on channel bonding.

Claims (14)

1. In a method for transmitting an AP signal in a WLAN system,

   The AP allocates M channels to the first station (STA) and transmits signals by allocating M channels to the second STA,

   When at least two channels are allocated to at least one of the first STA and the second STA, the AP may perform channel bonding or channel aggregation to at least one of the first STA and the second STA. Signal through)

   When there is a overlapping first channel among the M channels and the N channels, a signal transmitted to the first STA and a signal transmitted to the second STA in the first channel are precoded to each signal. A signal transmission method that is distinguished from each other. (M and N are natural numbers)
2. The method of claim 1,

   Precoding for multistream transmission to the first STA and the second STA is applied to the first channel.

   Precoding for signal transmission only to the first STA is applied to a second channel that is not overlapped with the N channels among the M channels.
3. The method of claim 1,

   When the values of M and N are different from each other,

   A subcarrier adjacent to a subcarrier used for signal transmission to the second STA among the subcarriers used for signal transmission to the first STA is used as a guard tone.
4. The method of claim 1,

   If the M value is 2 or more, the total bandwidth of the M channels used for signal transmission to the first STA is greater than N times the bandwidth of one channel.
5. The method of claim 1,

   The signal that the AP transmits to the first STA,

   And at least one of bandwidth information and channelization information allocated to the first STA.
6. The method of claim 5,

   The signal transmitted by the AP to the first STA further includes group identification information.
7. The method of claim 5,

   At least one of bandwidth information and channelization information allocated to the first STA is included in a header for a first type STA or a header for a second type STA of a signal transmitted to the first STA.
8. The method of claim 5,

   At least one of bandwidth information and channelization information allocated to the first STA is indicated by at least one bit indicator.
9. The method of claim 8,

   At least one of bandwidth information and channelization information allocated to the first STA is indicated by a bit indicator corresponding to the maximum number of channels supported by the system.

   Each bit indicator indicates in an on / off manner whether a channel corresponding to each bit indicator is allocated to the first STA.
10. The method of claim 1,

    The bandwidth of one channel is 1.83 GHz.
11. The method of claim 1,

    The maximum value of the M and N is 4, the signal transmission method.
12. A method for transmitting a signal to an access point (AP) by a first station (STA) in a WLAN system,

    The first STA is allocated two or more channels from the AP,

    The first STA transmits a signal to the AP through the allocated channel,

    When there is a overlapping first channel among a channel allocated to the first STA and a channel allocated to the second STA, a signal transmitted by the first STA and a signal transmitted by the second STA in each of the first channels are each A signal transmission method, which is distinguished from each other through precoding applied to a signal.
13. An access point apparatus for transmitting a signal in a WLAN system,

    A processor for allocating M channels to the first station (STA) and allocating N channels to the second STA; And

    A transceiver connected to the processor and configured to transmit a signal to the first STA and the second STA, respectively,

    When at least two channels are allocated to at least one of the first STA and the second STA, the AP may perform channel bonding or channel aggregation to at least one of the first STA and the second STA. Signal through)

    When there is a overlapping first channel among the M channels and the N channels, a signal transmitted to the first STA and a signal transmitted to the second STA in the first channel are precoded to each signal. Access point apparatus configured to be distinguished from each other. (M and N are natural numbers)
14. In a station for transmitting a signal in a WLAN system,

    A transceiver configured to transmit a signal; And

    Including a processor for controlling the transceiver,

    The processor is assigned two or more channels from an access point (AP),

    The processor controls the transceiver to transmit a signal to the AP through the assigned channel,

    When there is a overlapping first channel among a channel allocated to the first STA and a channel allocated to the second STA, a signal transmitted by the first STA and a signal transmitted by the second STA in each of the first channels are each And configured to be distinguished from each other via precoding applied to the signal.

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