WO2019208989A1 - Method for communicating through multiple channels in wireless lan system, and apparatus using same - Google Patents

Abstract

The present specification proposes a technical feature related to a wake-up radio (WUR) STA. The WUR STA may operate on the basis of a WUR beacon. In addition, the WUR STA may receive a WUR frame, on the basis of multiple frequency channels. Among various types of WUR frames, the WUR beacon may be received through one channel, for example, through only a first channel. When the WUR beacon is received through only the first channel, use of a second channel may be restricted for a specific time section related to the WUR beacon.

Description

 Method for communicating through a plurality of channels in a WLAN system and apparatus using the same

 The present disclosure relates to wireless communication, and more particularly, to a method for receiving a beacon message in a WLAN system and an apparatus using the same.

 Discussion is underway for the next generation wireless local area network (WLAN). In next-generation WLANs, 1) enhancements to the Institute of Electronics and Electronics Engineers (IEEE) 802.11 physical physical access (PHY) and medium access control (MAC) layers in the 2.4 GHz and 5 GHz bands, and 2) spectral efficiency and area throughput. aims to improve performance in real indoor and outdoor environments, such as in environments where interference sources exist, dense heterogeneous network environments, and high user loads.

The environment mainly considered in the next-generation WLAN is a dense environment having many access points (APs) and a station (STA), and improvements in spectral efficiency and area throughput are discussed in such a dense environment. In addition, in the next generation WLAN, there is an interest in improving practical performance not only in an indoor environment but also in an outdoor environment, which is not much considered in a conventional WLAN.

Specifically, in next-generation WLANs, we are interested in scenarios such as wireless office, smart-home, stadium, hot spot, building / apartment and based on the scenario. As a result, there is a discussion about improving system performance in a dense environment with many AP and STA.

Furthermore, WUR (Wake-up Radio), a method of waking a device only when data transmission is required, may be considered in order to extend battery life of devices and sensors on the IoT network and maintain optimal device performance. The WUR technique may be embodied through, for example, the Institute of Electrical and Electronics Engineers (IEEE) 802.11ba specification.

 An object of the present specification is to propose a technique for improving the operation of a WUR STA. For example, when the WUR STA supports different frequency channels, a channel for receiving a beacon message for WUR operation and a channel for receiving a WUR frame other than a beacon may be different. An object of the present specification is to propose a method and apparatus for efficiently receiving a beacon message for WUR operation.

 The present specification proposes a method and apparatus for a wireless local area network (WLAN) system.

A WUR STA according to an example of the present specification includes a main radio receiver for receiving a WLAN packet and a wake-up radio (WUR) receiver for receiving a wake-up radio (WUR) packet that is modulated by an on-off keying (OOK) technique. It may include.

The WUR STA may transmit information related to WUR capability to an access point (AP). For example, the information related to the WUR capability may include information related to a WUR frequency division multiple access (FDMA) operation of the WUR STA. The WUR FDMA may support a first channel including a WUR primary channel and a second channel different from the first channel.

The WUR STA may receive first control information related to a transmission time of a WUR beacon from the AP, for example, the WUR beacon is synchronized between the WUR STA and the AP. Used to maintain the WUR beacon may be received over the first channel.

The WUR STA may obtain second control information related to a waiting time related to the WUR beacon.

The WUR STA may receive a WUR packet on the first channel and / or the second channel. In this case, the WUR STA preferably stops the reception on the second channel for the waiting time after the transmission time of the WUR beacon.

 The WUR STA according to the present specification may efficiently receive a WUR frame through a plurality of channels. That is, beacons may be received using specific channel / time resources, and general WUR frames may be efficiently received using other channel / time resources. In this way, the WUR STA may receive beacons and / or WUR frames while efficiently using radio resources.

 1 is a conceptual diagram illustrating a structure of a WLAN system.

2 is a diagram illustrating an example of a PPDU used in the IEEE standard.

3 is a conceptual diagram illustrating an authentication and association procedure after scanning of an AP and an STA.

4 shows an internal block diagram of a wireless terminal receiving a wakeup packet.

5 is a conceptual diagram illustrating a method for a wireless terminal to receive a wakeup packet and a data packet.

6 shows an example of a format of a wakeup packet.

7 shows a signal waveform of a wakeup packet.

FIG. 8 is a diagram for describing a procedure of determining power consumption according to a ratio of bit values constituting information in a binary sequence form.

9 is a diagram illustrating a design process of a pulse according to the OOK technique.

10 is a diagram illustrating basic operations for a WUR STA.

11 is a diagram illustrating a signaling procedure for a WUR module according to an embodiment.

12 is a diagram illustrating an example of an operation for ending a WUR mode.

FIG. 13 is a diagram illustrating a concept of allocation of a WUR on state and a WUR off state in a WUR mode.

14 is an example of a WUR Parameter Request frame. Each field illustrated in FIG. 14 may be changed, and some fields may be omitted.

15 is an example of a WUR Parameter Response frame. Each field shown in FIG. 15 may be changed, and some fields may be omitted.

16 is a diagram illustrating a WUR FDMA technique in which a WUR STA operates.

17 is an additional diagram illustrating a WUR FDMA technique with WUR STA operation.

18 shows an example of a WUR Beacon frame received over a primary channel.

19 is a diagram illustrating an example of transmitting / receiving a WUR beacon according to an example of the present specification.

20 is a diagram illustrating an additional example of transmitting / receiving a WUR beacon according to an example of the present specification.

21 is a procedure flowchart to which an example of the present invention is applied.

22 is a flowchart illustrating an example of the present invention applied to an AP.

FIG. 23 is an example of a frame that conveys information about a transmission time of a WUR beacon.

24 shows an example of a terminal to which an example of the present specification is applied.

25 shows another example of a detailed block diagram of a transceiver.

 As used herein, the slash (/) or comma (comma) may mean "and / or". For example, “A / B” means “A and / or B,” and therefore may mean “only A”, “only B” or “A and B”. In addition, technical features that are separately described in one drawing may be implemented separately or may be simultaneously implemented.

In addition, parentheses used herein may mean “for example”. Specifically, when displayed as "control information (WUR-Signal)", "WUR-Signal" may be proposed as an example of "control information". In addition, even when displayed as “control information (ie, WUR-signal)”, “WUR-signal” may be proposed as an example of “control information”.

1 is a conceptual diagram illustrating a structure of a WLAN system. FIG. 1A shows the structure of an infrastructure network of the Institute of Electrical and Electronic Engineers (IEEE) 802.11.

Referring to FIG. 1A, the WLAN system 10 of FIG. 1A may include at least one basic service set (hereinafter, referred to as 'BSS', 100, 105). The BSS is a set of access points (APs) and stations (STAs) that can successfully synchronize and communicate with each other, and is not a concept indicating a specific area.

For example, the first BSS 100 may include a first AP 110 and one first STA 100-1. The second BSS 105 may include a second AP 130 and one or more STAs 105-1, 105-2.

The infrastructure BSS (100, 105) may include at least one STA, AP (110, 130) providing a distribution service (Distribution Service) and a distribution system (DS, 120) connecting a plurality of APs. have.

The distributed system 120 may connect the plurality of BSSs 100 and 105 to implement an extended service set 140 which is an extended service set. The ESS 140 may be used as a term indicating one network to which at least one AP 110 or 130 is connected through the distributed system 120. At least one AP included in one ESS 140 may have the same service set identification (hereinafter, referred to as SSID).

The portal 150 may serve as a bridge for connecting the WLAN network (IEEE 802.11) with another network (for example, 802.X).

In a WLAN having a structure as shown in FIG. 1A, a network between APs 110 and 130 and a network between APs 110 and 130 and STAs 100-1, 105-1, and 105-2 may be implemented. Can be.

1B is a conceptual diagram illustrating an independent BSS. Referring to FIG. 1B, the WLAN system 15 of FIG. 1B performs communication by setting a network between STAs without the APs 110 and 130, unlike FIG. 1A. It may be possible to. A network that performs communication by establishing a network even between STAs without the APs 110 and 130 is defined as an ad-hoc network or an independent basic service set (BSS).

Referring to FIG. 1B, the IBSS 15 is a BSS operating in an ad-hoc mode. Since IBSS does not contain an AP, there is no centralized management entity. Thus, in the IBSS 15, the STAs 150-1, 150-2, 150-3, 155-4, and 155-5 are managed in a distributed manner.

All STAs 150-1, 150-2, 150-3, 155-4, and 155-5 of the IBSS may be mobile STAs, and access to a distributed system is not allowed. All STAs of the IBSS form a self-contained network.

The STA referred to herein includes a medium access control (MAC) conforming to the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard and a physical layer interface to a wireless medium. As any functional medium, it can broadly be used to mean both an AP and a non-AP Non-AP Station (STA).

The STA referred to herein includes a mobile terminal, a wireless device, a wireless transmit / receive unit (WTRU), a user equipment (UE), and a mobile station (MS). It may also be called various names such as a mobile subscriber unit or simply a user.

2 is a diagram illustrating an example of a PPDU used in the IEEE standard.

As shown, various types of PHY protocol data units (PPDUs) have been used in the IEEE a / g / n / ac standard. Specifically, the LTF and STF fields included training signals, the SIG-A and SIG-B included control information for the receiving station, and the data fields included user data corresponding to the PSDU.

This embodiment proposes an improved technique for the signal (or control information field) used for the data field of the PPDU. The signal proposed in this embodiment may be applied on a high efficiency PPDU (HE PPDU) according to the IEEE 802.11ax standard. That is, the signals to be improved in the present embodiment may be HE-SIG-A and / or HE-SIG-B included in the HE PPDU. Each of HE-SIG-A and HE-SIG-B may also be represented as SIG-A or SIG-B. However, the improved signal proposed by this embodiment is not necessarily limited to the HE-SIG-A and / or HE-SIG-B standard, and controls / control of various names including control information in a wireless communication system for transmitting user data. Applicable to data fields.

Also, the HE PPDU of FIG. 2 is an example of a PPDU for multiple users. The HE-SIG-B is included only for the multi-user, and the HE-SIG-B may be omitted in the PPDU for the single user.

As shown, a HE-PPDU for a multiple user (MU) includes a legacy-short training field (L-STF), a legacy-long training field (L-LTF), a legacy-signal (L-SIG), High efficiency-signal A (HE-SIG-A), high efficiency-signal-B (HE-SIG-B), high efficiency-short training field (HE-STF), high efficiency-long training field (HE-LTF) It may include a data field (or MAC payload) and a PE (Packet Extension) field. Each field may be transmitted during the time period shown (ie, 4 or 8 ms, etc.).

The PPDU used in the IEEE standard is mainly described as a PPDU structure transmitted over a channel bandwidth of 20 MHz. The PPDU structure transmitted over a wider bandwidth (eg, 40 MHz, 80 MHz) than the channel bandwidth of 20 MHz may be a structure applying linear scaling to the PPDU structure used in the 20 MHz channel bandwidth.

The PPDU structure used in the IEEE standard is generated based on 64 Fast Fourier Tranforms (FTFs), and a CP portion (cyclic prefix portion) may be 1/4. In this case, the length of the effective symbol interval (or FFT interval) may be 3.2us, the CP length is 0.8us, and the symbol duration may be 4us (3.2us + 0.8us) plus the effective symbol interval and the CP length.

3 is a conceptual diagram illustrating an authentication and association procedure after scanning of an AP and an STA.

Referring to FIG. 3, a non-AP STA may perform an authentication and combining procedure with one of a plurality of APs that have completed a scanning procedure through passive / active scanning. For example, authentication and association procedures may be performed through two-way handshaking.

FIG. 3A is a conceptual diagram illustrating an authentication and combining procedure after passive scanning, and FIG. 3B is a conceptual diagram illustrating an authentication and combining procedure after active scanning.

The authentication and association procedure can be performed regardless of whether an active scanning method or passive scanning was used. For example, the APs 300 and 350 may connect to the non-AP STAs 305 and 355, an authentication request frame 310, an authentication response frame 320, and an association request frame. , 330, and association response frame 340, the authentication and association procedure may be performed.

In detail, the authentication procedure may be performed by transmitting the authentication request frame 310 to the APs 300 and 350 in the non-AP STAs 305 and 355. The AP 300 or 350 may transmit the authentication response frame 320 to the non-AP STAs 305 and 355 in response to the authentication request frame 310. Authentication frame format is described in IEEE 802.11 8.3.3.11.

In detail, the joining procedure may be performed by transmitting the join request frame 330 to the APs 300 and 305 in the non-AP STAs 305 and 355. The AP 300 or 350 may transmit the association response frame 440 to the non-AP STAs 305 and 355 in response to the association request frame 330.

The association request frame 330 may include information regarding the capability of the non-AP STAs 305 and 355. The APs 300 and 350 may determine whether to support the non-AP STAs 305 and 355 based on the information about the performance of the non-AP STAs 305 and 355 included in the association request frame 430. Can be.

For example, when the support for the non-AP STAs 305 and 355 is possible, the APs 300 and 350 may support the association request frame 330 in the association response frame 340, and why and the support thereof. Capability information may be included and transmitted to the non-AP STAs 305 and 355. Association frame format is described in IEEE 802.11 8.3.3.5/8.3.3.6.

If the combined procedure mentioned in FIG. 3 is performed, a normal data transmission and reception procedure may be performed between the AP and the STA.

4 shows an internal block diagram of a wireless terminal receiving a wakeup packet.

Referring to FIG. 4, the WLAN system 400 according to the present embodiment may include a first wireless terminal 410 and a second wireless terminal 420.

The first wireless terminal 410 includes a WUR module 412 that includes a main radio module 411 associated with the main radio (ie, 802.11 radio) and a low-power wake-up receiver ('LP WUR'). ) May be included. In the present specification, the main radio module may be referred to as a primary component radio (hereinafter, 'PCR') module. For example, the main radio module 411 may include a plurality of circuits supporting Wi-Fi, Bluetooth® radio (hereinafter referred to as BT radio) and Bluetooth® Low Energy radio (hereinafter referred to as BLE radio).

The WUR module 412 can be implemented in a variety of ways. For example, it is possible to be implemented in an embedded manner in the main radio module 411. That is, as shown in FIG. 4B, the WUR module 412 may be included in the main radio module 411. In FIG. 4A, the main radio module 411 and the WUR module 412 are displayed separately, but one example of FIG. 4A shows that the WUR module 412 is located within the radio module 411 in the same STA. To indicate inclusion. That is, the example of FIG. 4A may include an example of FIG. 4B.

In the present specification, the first wireless terminal 410 may control the main radio module 411 to an awake state or a doze state.

For example, when the main radio module 411 is in the awake state, the first radio terminal 410 is based on the main radio module 411, 802.11-based frame (eg, 802.11 type PPDU) Transmit or receive an 802.11-based frame. For example, the 802.11-based frame may be a non-HT PPDU of 20MHz band. An 802.11-based frame may be called various names such as WLAN packets.

As another example, when the main radio module 411 is in the doze state, the first radio terminal 410 transmits an 802.11 based frame (eg, an 802.11 type PPDU) based on the main radio module 411. Or receive 802.11 based frames.

That is, when the main radio module 411 is in the doze state (ie, in the OFF state), the WUR module 412 is connected to the main radio module 411 according to a wake-up packet. The first wireless terminal 400 cannot receive a frame (eg, an 802.11 type PPDU) transmitted by the second wireless terminal 420 (eg, an AP) until the wake up state is awake.

In the present specification, the first wireless terminal 410 may control the WUR module 412 in a turn-off state (ie, WUR off / dose state) or in a turn-on state (ie, WUR on / awake state). have.

For example, a first wireless terminal 410 that includes a WUR module 412 in a turn-on state can only receive certain types of frames transmitted by a second wireless terminal 420 (eg, an AP). have.

In this case, the specific type of frame may be a frame (that is, a wakeup packet) modulated by an On-Off Keying (OOK) modulation scheme described below with reference to FIG. 5.

For example, a first wireless terminal 410 that includes a WUR module 412 in a turn-off state (ie, WUR off / dose state) is transmitted by a second wireless terminal 420 (eg, an AP). It is not possible to receive certain types of frames (ie wakeup packets).

In the present specification, the first wireless terminal 410 may operate independently of the main radio module (ie, the PCR module 411) and the WUR module 412.

For example, when the main radio module 411 is in an awake state and the WUR module 412 is in a turn-off state (ie, WUR off / dose state), the first wireless terminal 410 is in WLAN mode. It can be said to operate as. Further, for example, when the WUR module 412 is in the turn-on state, it may be said that the first wireless terminal 410 operates in the WUR mode. However, this definition may be modified in the following specific examples.

The first wireless terminal 410 in the WUR mode may receive a wakeup packet (WUP) based on the WUR module 412 in the turn-on state. In addition, when a wakeup packet (WUP) is received by the WUR module 412, the first wireless terminal 410 in the WUR mode may control the WUR module 412 to wake up the main radio module 411. .

It may also be said that when the main radio module 411 is in the doze state and the WUR module 412 is in the turn-on state, the first wireless terminal 410 operates in the WUR-PS mode.

In this specification, to indicate the ON state of a specific module included in the wireless terminal, the terms for the awake state and the turn-on state may be used interchangeably. In the same context, the terms for the dose state and the turn-off state may be used interchangeably to indicate the OFF state of a particular module included in the wireless terminal.

The first wireless terminal 410 according to the present embodiment is based on a frame (for example, 802.11 based) from another wireless terminal 420 (for example, AP) based on the main radio module 411 or the WUR module 412 in an active state. PPDU) can be received.

The WUR module 412 may be a receiver for transitioning the main radio module 411 in the doze state to an awake state. That is, the WUR module 412 may not include a transmitter.

The first wireless terminal 410 can operate the WUR module 412 in the turn-on state for the duration in which the main radio module 411 is in the doze state.

For example, when a wakeup packet is received based on the WUR module 412 in the turned-on state, the first wireless terminal 410 causes the main radio module 411 in the doze state to transition to the awake state. Can be controlled.

For reference, the low power wake-up receiver LP WUR included in the WUR module 412 targets a target power consumption of less than 1 mW in an activated state. In addition, low power wake-up receivers may use a narrow bandwidth of less than 5 MHz.

In addition, the power consumption by the low power wake-up receiver may be less than 1 Mw. In addition, the target transmission range of the low power wake-up receiver may be implemented in the same manner as the target transmission range of the existing 802.11.

The second wireless terminal 420 according to the present embodiment may transmit user data based on a main radio (ie, 802.11). The second wireless terminal 420 can transmit a wakeup packet (WUP) for the WUR module 412.

5 is a conceptual diagram illustrating a method for a wireless terminal to receive a wakeup packet and a data packet. The wireless terminal of FIG. 5 is based on the wireless terminal of FIG. 4, and each module of FIG. 5 corresponds to each module of FIG. 4.

4 and 5, the WLAN system 500 according to the present embodiment may include a first wireless terminal 510 corresponding to the receiving terminal and a second wireless terminal 520 corresponding to the transmitting terminal. have.

Basic operations of the first wireless terminal 510 of FIG. 5 may be understood through the description of the first wireless terminal 410 of FIG. 4. In addition, the basic operation of the second wireless terminal 520 of FIG. 5 may be understood through the description of the second wireless terminal 420 of FIG. 4.

Referring to FIG. 5, a wakeup packet 521 may be received by the WUR module 512 in a turn-on state (eg, an ON state).

In this case, the WUR module 512 doses the wakeup signal 523 (ie, the OFF state) in order for the main radio module 511 to correctly receive the data packet 522 to be received after the wakeup packet 521. It can be delivered to the main radio module 511 in the. For example, the data packet 522 may be implemented as a PPDU of various formats shown in FIG. 2 as a WLAN packet.

For example, the wakeup signal 523 may be implemented based on an internal primitive of the first wireless terminal 510.

For example, when the wake-up signal 523 is received by the main radio module 511 in the doze state (ie, the OFF state), the first radio terminal 510 wakes up the main radio module 511. That is, it can be controlled to transition to the ON state).

For example, when the main radio module 511 transitions from the doze state (ie, OFF state to awake state (ie, ON state), the first wireless terminal 510 is included in the main radio module 511. A plurality of circuits (not shown) supporting Wi-Fi, BT radio, and BLE radio may be activated in whole or in part.

As another example, the actual data included in the wakeup packet 521 may be directly transmitted to the memory block (not shown) of the receiving terminal even if the main radio module 511 is in the doze state (ie, the OFF state).

As another example, when the wake-up packet 521 includes an IEEE 802.11 MAC frame, the receiving terminal may activate only the MAC processor of the main radio module 511. That is, the receiving terminal may maintain the PHY module of the main radio module 511 in an inactive state. The wakeup packet 521 of FIG. 5 will be described in more detail with reference to the following drawings.

The second wireless terminal 520 can be set to transmit the wakeup packet 521 to the first wireless terminal 510.

6 shows an example of a format of a wakeup packet.

1 to 6, the wakeup packet 600 may include one or more legacy preambles 610. In addition, the wakeup packet 600 may include a payload 620 after the legacy preamble 610. The payload 620 may be modulated by a simple modulation scheme (eg, an On-Off Keying (OOK) modulation scheme). The wakeup packet 600 including the payload may be relatively small. It may be transmitted based on bandwidth.

1 through 6, a second wireless terminal (eg, 520) may be configured to generate and / or transmit wakeup packets 521, 600. The first wireless terminal (eg, 510) can be configured to process the received wakeup packet 521.

For example, the wakeup packet 600 may include a legacy preamble 610 or any other preamble (not shown) defined in the existing IEEE 802.11 standard. The wakeup packet 600 may include one packet symbol 615 after the legacy preamble 610. In addition, the wakeup packet 600 may include a payload 620.

The legacy preamble 610 may be provided for coexistence with the legacy STA. In the legacy preamble 610 for coexistence, an L-SIG field for protecting a packet may be used.

For example, the 802.11 STA may detect the beginning of a packet through the L-STF field in the legacy preamble 610. The STA may detect an end portion of the 802.11 packet through the L-SIG field in the legacy preamble 610.

In order to reduce false alarm of the 802.11n terminal, a modulated symbol 615 may be added after the L-SIG of FIG. 6. One symbol 615 may be modulated according to a BiPhase Shift Keying (BPSK) technique. One symbol 615 may have a length of 4 us. One symbol 615 may have a 20 MHz bandwidth like a legacy part.

The legacy preamble 610 may be understood as a field for a third party legacy STA (STA that does not include the LP-WUR). In other words, the legacy preamble 610 may not be decoded by the LP-WUR.

Payload 620 includes a wake-up preamble field 621, a MAC header field 623, a frame body field 625, and a Frame Check Sequence (FCS) field 627. can do.

The wakeup preamble field 621 may include a sequence for identifying the wakeup packet 600. For example, the wakeup preamble field 621 may include a pseudo random noise sequence (PN).

The MAC header field 624 may include address information (or an identifier of a receiving apparatus) indicating a receiving terminal receiving the wakeup packet 600. The frame body field 626 may include other information of the wakeup packet 600.

The frame body 626 may include length information or size information of the payload. Referring to FIG. 6, the length information of the payload may be calculated based on length LENGTH information and MCS information included in the legacy preamble 610.

The FCS field 628 may include a Cyclic Redundancy Check (CRC) value for error correction. For example, the FCS field 628 may include a CRC-8 value or a CRC-16 value for the MAC header field 623 and the frame body 625.

Some of each field shown in FIG. 6 may be omitted. That is, some of the fields shown in FIG. 6 may not be essential fields.

7 shows a signal waveform of a wakeup packet.

Referring to FIG. 7, the wakeup packet 700 may include payloads 722 and 724 modulated based on a legacy preamble (802.11 preamble, 710) and an On-Off Keying (OOK) scheme. That is, the wakeup packet WUP according to the present embodiment may be understood as a form in which a legacy preamble and a new LP-WUR signal waveform coexist.

In the legacy preamble 710 of FIG. 7, the OOK technique may not be applied. As mentioned above, payloads 722 and 724 may be modulated according to the OOK technique. However, the wakeup preamble 722 included in the payloads 722 and 724 may be modulated according to another modulation technique.

For example, it may be assumed that the legacy preamble 710 is transmitted based on a channel band of 20 MHz to which 64 FFTs are applied. In this case, payloads 722 and 724 may be transmitted based on a channel band of about 4.06 MHz.

FIG. 8 is a diagram for describing a procedure of determining power consumption according to a ratio of bit values constituting information in a binary sequence form.

Referring to FIG. 8, information in the form of a binary sequence having '1' or '0' as a bit value may be represented. Communication based on the OOK modulation scheme may be performed based on the bit values of the binary sequence information.

For example, when the light emitting diode is used for visible light communication, when the bit value constituting the binary sequence information is '1', the light emitting diode is turned on, and when the bit value is '0', the light emitting diode is turned off. (off) can be turned off.

As the light-emitting diode blinks, the receiver receives and restores data transmitted in the form of visible light, thereby enabling communication using visible light. However, since the blinking of the light emitting diode cannot be perceived by the human eye, the person feels that the illumination is continuously maintained.

For convenience of description, as shown in FIG. 8, information in the form of a binary sequence having 10 bit values may be provided. For example, information in the form of a binary sequence having a value of '1001101011' may be provided.

As described above, when the bit value is '1', when the transmitting terminal is turned on and when the bit value is '0', when the transmitting terminal is turned off, 6 bit values of the above 10 bit values are applied. The corresponding symbol is turned on.

Since the wake-up receiver WUR according to the present embodiment is included in the receiving terminal, the transmission power of the transmitting terminal may not be greatly considered. The reason why the OOK technique is used in the present embodiment is because power consumption in the decoding procedure of the received signal is very small.

Until the decoding procedure is performed, there may be no significant difference between the power consumed by the main radio and the power consumed by the WUR. However, as the decoding procedure is performed by the receiving terminal, a large difference may occur between power consumed by the main radio module and power consumed by the WUR module. Below is the approximate power consumption.

-The existing Wi-Fi power consumption is about 100mW. Specifically, power consumption of Resonator + Oscillator + PLL (1500uW)-> LPF (300uW)-> ADC (63uW)-> decoding processing (Orthogonal frequency-division multiplexing (OFDM) receiver) (100mW) may occur.

-WUR power consumption is about 1mW. Specifically, power consumption of Resonator + Oscillator (600uW)-> LPF (300uW)-> ADC (20uW)-> decoding processing (Envelope detector) (1uW) may occur.

9 is a diagram illustrating a design process of a pulse according to the OOK technique.

The wireless terminal according to the present embodiment may use an existing orthogonal frequency-division multiplexing (OFDM) transmitter of 802.11 to generate pulses according to the OOK technique. The existing 802.11 OFDM transmitter can generate a sequence having 64 bits by applying a 64-point IFFT.

1 to 9, the wireless terminal according to the present embodiment may transmit a payload of a wakeup packet (WUP) modulated according to the OOK technique. The payload (eg, 620 of FIG. 6) according to the present embodiment may be implemented based on an ON-signal and an OFF-signal.

The OOK technique may be applied to the ON-signal included in the payload of the wakeup packet WUP (eg, 620 of FIG. 6). In this case, the on signal may be a signal having an actual power value.

Referring to the frequency domain graph 920, the ON signal included in the payload (eg, 620 of FIG. 6) is N2 among N1 subcarriers (N1 is a natural number) corresponding to the channel band of the wakeup packet (WUP). Can be obtained by performing IFFT on the subcarriers N2 is a natural number. In addition, a predetermined sequence may be applied to the N2 subcarriers.

For example, the channel band of the wakeup packet WUP may be 20 MHz. The N1 subcarriers may be 64 subcarriers, and the N2 subcarriers may be 13 consecutive subcarriers (921 of FIG. 9). The subcarrier interval applied to the wakeup packet (WUP) may be 312.5 kHz.

The OOK technique may be applied for the OFF-signal included in the payload (eg, 620 of FIG. 6) of the wakeup packet WUP. The off signal may be a signal that does not have an actual power value. That is, the off signal may not be considered in the configuration of the wakeup packet (WUP).

The ON signal included in the payload (620 of FIG. 6) of the wakeup packet WUP is determined as a 1-bit ON signal (ie, '1') by the WUR module (eg, 512 of FIG. 5) ( That is, demodulation). Similarly, the off signal included in the payload may be determined (ie, demodulated) as a 1-bit off signal (ie, '0') by the WUR module (eg, 512 of FIG. 5).

A specific sequence may be preset for the subcarrier set 921 of FIG. 9. In this case, the preset sequence may be a 13-bit sequence. For example, a coefficient corresponding to the DC subcarrier in the 13-bit sequence may be '0', and the remaining coefficients may be set to '1' or '-1'.

Referring to the frequency domain graph 920, the subcarrier set 921 may correspond to a subcarrier having a subcarrier index of '-6' to '+6'.

For example, a coefficient corresponding to a subcarrier whose subcarrier indices are '-6' to '-1' in the 13-bit sequence may be set to '1' or '-1'. A coefficient corresponding to a subcarrier whose subcarrier indices are '1' to '6' in the 13-bit sequence may be set to '1' or '-1'.

For example, a subcarrier whose subcarrier index is '0' in a 13-bit sequence may be nulled. The coefficients of the remaining subcarriers (subcarrier indexes '-32' to '-7' and subcarrier indexes '+7' to '+31') except for the subcarrier set 921 are all set to '0'. Can be.

The subcarrier set 921 corresponding to 13 consecutive subcarriers may be set to have a channel bandwidth of about 4.06 MHz. That is, power by signals may be concentrated at 4.06 MHz in the 20 MHz band for the wakeup packet (WUP).

When the pulse according to the OOK technique is used according to the present embodiment, the power is concentrated in a specific band, so that the signal to noise ratio (SNR) may be increased, and the power consumption for conversion in the AC / DC converter of the receiver may be reduced. There is an advantage that it can. Since the sampling frequency band is reduced to 4.06 MHz, power consumption by the wireless terminal can be reduced.

According to the embodiment of the present invention, an OFDM transmitter of 802.11 may have N2 (e.g., 13 consecutive) subs of N1 (e.g., 64) subcarriers corresponding to the channel band (e.g., 20 MHz band) of the wake-up packet. IFFT (eg, 64-point IFFT) may be performed on the carrier.

In this case, a predetermined sequence may be applied to the N2 subcarriers. Accordingly, one on-signal may be generated in the time domain. One bit information corresponding to one on signal may be transmitted through one symbol.

For example, when a 64-point IFFT is performed, a symbol having a 3.2us length corresponding to the subcarrier set 921 may be generated. In addition, when CP (Cyclic Prefix, 0.8us) is added to a symbol having a 3.2us length corresponding to the subcarrier set 921, one symbol having a total length of 4us as shown in the time domain graph 910 of FIG. Can be generated.

In addition, the OFDM transmitter of 802.11 may not transmit the off signal at all.

According to the present embodiment, a first wireless terminal (eg, 510 of FIG. 5) including a WUR module (eg, 512 of FIG. 5) may receive a packet based on an envelope detector that extracts an envelope of the received signal. Can be demodulated.

For example, the WUR module (eg, 512 of FIG. 5) according to the present embodiment may compare a power level of a received signal obtained through an envelope of the received signal with a preset threshold level.

If the power level of the received signal is higher than the threshold level, the WUR module (eg, 512 of FIG. 5) may determine the received signal as a 1-bit ON signal (ie, '1'). If the power level of the received signal is lower than the threshold level, the WUR module (eg, 512 of FIG. 5) may determine the received signal as a 1-bit OFF signal (ie, '0').

Generalizing the contents of FIG. 9, each signal having a length of K (eg, K is a natural number) in the 20 MHz band may be transmitted based on consecutive K subcarriers of 64 subcarriers for the 20 MHz band. For example, K may correspond to the number of subcarriers used to transmit the signal. K may also correspond to the bandwidth of a pulse according to the OOK technique.

All of the coefficients of the remaining subcarriers except K subcarriers among the 64 subcarriers may be set to '0'.

Specifically, for the 1-bit off signal corresponding to '0' (hereinafter, information 0) and the 1-bit on signal corresponding to '1' (hereinafter, information 1), the same K subcarriers may be used. have. For example, the index for the K subcarriers used may be expressed as 33-floor (K / 2): 33 + ceil (K / 2) -1.

In this case, the information 1 and the information 0 may have the following values.

Information 0 = zeros (1, K)

Information 1 = alpha * ones (1, K)

The alpha is a power normalization factor and may be, for example, 1 / sqrt (K).

10 is a diagram illustrating basic operations for a WUR STA.

For example, the AP 1000 of FIG. 10 may be based on the second wireless terminal 520 of FIG. 5. The horizontal axis of the AP 1000 of FIG. 10 may indicate a time ta. The vertical axis of the AP 1000 of FIG. 10 may be associated with the presence of a packet (or frame) to be transmitted by the AP 1000.

For example, the WUR STA 1010 of FIG. 10 may be based on the first wireless terminal 510 of FIG. 5. The WUR STA 1010 may include a main radio module (PCR # m) 1011 and a WUR module (PCR # m) 1012. The main radio module 1011 of FIG. 10 may correspond to the main radio module 511 of FIG. 5.

In detail, the main radio module 1011 may perform a reception operation for receiving an 802.11 based packet (ie, a WLAN packet / signal) from the AP 1000 and a transmission operation for transmitting an 802.11 based packet to the AP 1000. It can support all of them. For example, the 802.11-based packet may be a packet modulated according to the OFDM technique.

The horizontal axis of the main radio module 1011 may indicate a time tm. An arrow displayed at the bottom of the horizontal axis of the main radio module 1011 may be associated with a power state (eg, an ON state or an OFF state) of the main radio module 1011. The vertical axis of the main radio module 1011 may be associated with the presence of a packet to be transmitted based on the main radio module 1011.

The WUR module 1012 of FIG. 10 may correspond to the WUR module 512 of FIG. 5. In detail, the WUR module 1012 may support only a reception operation for a packet modulated from the AP 1000 according to an on-off keying (OOK) technique.

The horizontal axis of the WUR module 1012 may indicate a time tw. In addition, an arrow displayed at the bottom of the horizontal axis of the WUR module 1012 may be associated with a power state (eg, a WUR ON state or a WUR OFF / doze state) of the WUR module 1012.

The WUR STA 1010 of FIG. 10 may be understood as an associated wireless terminal by performing an association procedure with the AP 1000.

5 and 10, the AP 1000 of FIG. 10 may correspond to the second wireless terminal 520 of FIG. 5. The horizontal axis of the AP 1000 of FIG. 10 may represent time ta. The vertical axis of the AP 1000 of FIG. 10 may be associated with the presence of a packet (or frame) to be transmitted by the AP 1000.

The WUR STA 1010 may correspond to the first wireless terminal 510 of FIG. 5. The WUR STA 1010 may include a main radio module PCR # m 1011 and a WUR module WUR # m 1012. The main radio module 1011 of FIG. 10 may correspond to the main radio module 511 of FIG. 5.

In detail, the main radio module 1011 may support both a reception operation for receiving an 802.11-based packet from the AP 1000 and a transmission operation for transmitting an 802.11-based packet to the AP 1000. For example, the 802.11-based packet may be a packet modulated according to the OFDM technique.

The horizontal axis of the main radio module 1011 may represent time tm. An arrow displayed at the bottom of the horizontal axis of the main radio module 1011 may be associated with a power state (eg, an ON state or an OFF state) of the main radio module 1011.

The vertical axis of the main radio module 1011 may be associated with the presence of a packet to be transmitted based on the main radio module 1011. The WUR module 1012 of FIG. 10 may correspond to the WUR module 512 of FIG. 5. In detail, the WUR module 1012 may support a reception operation for a packet modulated from the AP 1000 according to the OOK scheme.

The horizontal axis of the WUR module 1012 may represent time tw. In addition, an arrow displayed at the bottom of the horizontal axis of the WUR module 1012 may be associated with a power state (eg, an ON state or an OFF state) of the WUR module 1012.

In the wakeup periods TW to T1 of FIG. 10, the WUR STA 1010 may be in a WUR mode.

For example, the WUR STA 1010 may control the main radio module 1011 to be in a doze state (ie, an OFF state). In addition, the WUR STA 1010 may control the WUR module 1012 to be in a turn-on state (ie, in an ON state).

When a data packet for the WUR STA 1010 exists in the AP 1000, the AP 1000 may transmit a wakeup packet WUP to the WUR STA 1010 on a contention basis.

In this case, the WUR STA 1010 may receive a wakeup packet (WUP) based on the WUR module 1012 in a turn-on state (ie, an ON state). Here, the wakeup packet (WUP) may be understood based on the description mentioned above with reference to FIGS. 5 to 7.

In the first period T1 to T2 of FIG. 10, a wakeup signal (eg, 523 of FIG. 5) for waking up the main radio module 511 according to the wakeup packet WUP received by the WUR module 1012 is generated. It may be delivered to the main radio module 511.

In this specification, the time required for the main radio module 511 to transition from the doze state to the awake state according to the wake-up signal (eg, 523 of FIG. 5) is a turn-on delay (TOD). May be referred to as').

Referring to FIG. 10, when the turn-on delay (TOD) elapses, the WUR STA 1010 may be in a WLAN mode.

For example, when the turn-on delay TOD elapses, the WUR STA 1010 may control the main radio module 1011 to be in an awake state (ie, in an ON state). For example, when the wakeup periods TW to T1 elapse, the WUR STA 1010 may control the WUR module 1012 to be in a turn-off state (ie, a WUR off / dose state).

Subsequently, the WUR STA 1010 transmits a power save poll (PS-poll) frame to the AP 1000 based on the main radio module 1011 in an awake state (ie, in an ON state). I can send it.

Here, the PS-poll frame may be a frame for notifying that the WUR STA 1010 may receive a data packet for the WUR STA 1010 existing in the AP 1000 based on the main radio module 1011. . In addition, the PS-poll frame may be a frame transmitted on a contention basis with another wireless terminal (not shown).

Subsequently, the AP 1000 may transmit the first ACK frame ACK # 1 to the WUR STA 1010 in response to the PS-poll frame.

Subsequently, the AP 1000 may transmit a data packet for the WUR STA 1010 to the WUR STA 1010. In this case, a data packet for the WUR STA 1010 may be received based on the main radio module 1011 in an awake state (ie, an ON state).

Subsequently, the WUR STA 1010 may transmit a second ACK frame ACK # 2 for notifying a successful reception of a data packet Data for the WUR STA 1010 to the AP 1000.

Although not shown in FIG. 10, in the second periods T2 to T3 of FIG. 10, the WUR STA 1010 may transition from the WLAN mode to the WUR mode again for power saving.

11 is a diagram illustrating a signaling procedure for a WUR module according to an embodiment.

10 and 11, the AP 1100 of FIG. 11 may correspond to the AP 1000 of FIG. 10, and the WUR STA 1110 of FIG. 11 may correspond to the WUR STA 1010 of FIG. 10. . In addition, the main radio module 1111 of FIG. 11 may correspond to the main radio module 1011 of FIG. 10, and the WUR module 1112 of FIG. 11 may correspond to the WUR module 1012 of FIG. 10.

For a clear and concise understanding of FIG. 11, the WUR STA 1110 may be understood as a wireless terminal coupled with the AP 1100 by performing a joining procedure.

The AP 1100 of FIG. 11 needs to know an operation mode of the WUR STA 1110 in advance to efficiently transmit downlink data for the WUR STA 1110. That is, the WUR STA 1110 needs to inform the AP 1100 whenever it wants to change its operation mode.

In the first period T1 to T2 of FIG. 11, the WUR STA 1110 may be in a WLAN mode. For example, the WUR STA 1110 may control the main radio module 1111 to be in an awake state (ie, in an ON state). In addition, the WUR STA 1110 may control the WUR module 1112 to be in a turn-off state (ie, a WUR off / doze state).

In this case, when the WUR STA 1110 attempts to enter its operation mode from the WLAN mode to the WUR mode, the WUR STA 1110 sends an AP 1100 a WUR mode request frame of the WUR STA 1110. I can send it.

For example, the WUR mode request frame may include mode indication information for an operation mode requested by the WUR STA 1110. For example, the mode indication information may be set to a first value indicating that the WUR STA 1110 intends to enter the WUR mode or a second value indicating to suspend the WUR mode.

Here, the WUR mode request frame may be understood to include mode indication information set to a first value indicating that the WUR mode is to be entered.

For example, the WUR mode request frame may further include parameter information for duty cycle operation by the WUR module 1112.

Here, the parameter information for the duty cycle operation may include information on the On Duration preferred by the WUR module 1112. For example, the information about the on duration may indicate the length of time that the WUR module 1112 maintains an awake state (ie, a WUR on / awake state).

The parameter information for the duty cycle operation may further include information about a duty cycle period, which is a time between on durations of each WUR duty cycle.

As another example, the WUR mode request frame may further include information about a timeout value for the wakeup packet. For example, if a response is not received for a predetermined time after receiving the wakeup packet (WUP), the WUR STA 1110 may need to operate in the WUR mode again to receive the wakeup packet to be retransmitted.

As another example, the WUR mode request frame may further include information about Received RSSI and channel quality information. For example, in order to help the AP determine the transmission rate of the wakeup packet (WUP), the WUR STA 1110 may transmit a measurement value of a frame previously received from the AP 1100.

Subsequently, the WUR STA 1110 may receive a first ACK frame indicating the successful reception of the WUR mode request frame from the AP 1100 based on the main radio module 1111.

Subsequently, the WUR STA 1110 may receive a WUR mode response frame based on the main radio module 1111 in response to the WUR mode request frame from the AP 1100. Here, the WUR mode response frame may include WUR related information approved by the AP 1100 based on a request for mode change of the WUR STA 1110.

For example, the WUR related information may include status code information for approving or rejecting a request for a mode change of the WUR STA 1110.

For example, if the AP 1100 determines that the WUR mode of the WUR STA 1110 may be supported based on the WUR mode request frame, the status code information may include the grant information.

As another example, if the AP 1100 determines that the WUR mode request frame cannot support the WUR mode of the WUR STA 1110, the status code information may include rejection information along with a rejection reason.

For example, the WUR related information may include WUR Identifier (WUR ID) assignment information for the WUR STA 1110 determined by the AP 1100. In this case, the WUR identifier assignment information may be identification information for unicast or identification information for multicast or broadcast on a group basis.

For example, the WUR related information may include parameter information for a duty cycle operation determined by the AP 1100 based on the WUR mode request frame.

Here, the parameter information for the duty cycle operation determined by the AP 1100 may include information about a starting point of the duty cycle operation determined by the AP 1100.

As another example, the WUR related information may include information about a WUR channel to be used for the WUR mode determined by the AP 1100 based on the WUR mode request frame.

As another example, the WUR-related information may include information on a transmission rate of a unicast wakeup packet (WUP) determined by the AP 1100 based on a WUR mode request frame.

As another example, the WUR-related information may include information on a time stamp value for synchronizing with the WUR STA 1110 before operating in the WUR mode.

As another example, the WUR related information may include information on a WUR beacon frame so that the WUR STA 1110 can normally receive the WUR beacon while operating in the WUR mode.

Subsequently, after transmitting the second ACK frame indicating successful reception of the WUR mode response frame, the WUR STA 1110 may operate in the WUR mode based on the WUR-related information.

In the second period T2 to T3 of FIG. 11, the WUR STA 1110 has a QoS null frame or power management (PM) field set to '1' based on the main radio module 1111. The data frame may be transmitted to the AP 1100.

Subsequently, the WUR STA 1110 may receive a third ACK frame based on the main radio module 1111 indicating the successful reception of a QoS null frame or a data frame from the AP 1100.

When the third ACK frame is received, the WUR STA 1110 may control the main radio module 1111 to transition from an awake state (ie, an ON state) to a doze state (ie, an OFF state) for power saving. .

After the third time point T3 of FIG. 11, the WUR STA 1110 may operate in the WUR-PS mode. For example, the WUR STA 1110 may control the main radio module 411 to be in a doze state. In addition, the WUR STA 1110 may control the WUR module 412 to be in a turn-on state.

12 is a diagram illustrating an example of an operation for ending a WUR mode.

The WUR STA 1210 illustrated in FIG. 12 may enter the WUR mode according to the procedure of FIG. 11. The WUR STA 1210 and the AP 1200 illustrated in FIG. 12 may correspond to the entities illustrated in FIGS. 10 to 11.

In the WUR mode, the WUR module 1212 of the WUT STA 1210 may operate in one of a WUR on / awake state and a WUR off state (ie, a WUR dose state). . In addition, as described above, the length of the WUR on / off state may be set according to the duty cycle described above.

In the example of FIG. 12, the WUR STA 1210 may transmit a WUR Mode request to the AP 1200 to terminate the WUR mode. That is, the WUR STA 1210 may request termination of the WUR mode through a specific field in the WUR mode request. The AP 1210 may receive a WUR Mode request and transmit an ACK (ie, ACK # 1 shown).

The WUR STA 1210 may end the WUR mode immediately after receiving the ACK # 1. That is, it is possible to terminate the WUR mode after receiving ACK # 1 without receiving an additional WUR mode response from the AP. That is, after the time point T1 illustrated in FIG. 12, the WUR module 1212 of the WUR STA 1210 may end the WUR mode.

The WUR STA 1210 then transmits a QoS null frame with the PM bit set to "0" or some other response frame (e.g., a MAC frame with the PM bit set to "0"), and then to the QoS null frame. After receiving the ACK (ie, ACK # 2), the previous PS (power save) mode can be terminated and enter the active mode. The PCR module 1211 of FIG. 12 maintains the PS mode in which the awake / dose state is selectively set to T2, and terminates the PS mode after T2 to operate in the active mode. The general WIFI STA, that is, the PCR module, may operate in an active mode or a PS-mode. In the active mode, the signal is transmitted and / or received continuously, while in the PS-mode the on state (ie, awake state) and the off state (ie, the doze state) may be repeated.

As described above, the WUR STA operating in the WUR mode may operate in one of a WUR on / awake state and a WUR off state (that is, a WUR dose state). . Since the WUR on state and the WUR off state may be repeatedly arranged, the operation of the WUR mode may be understood as a concept of a duty cycle.

FIG. 13 is a diagram illustrating a concept of allocation of a WUR on state and a WUR off state in a WUR mode.

As shown, an on duration may be assigned, which means a WUR on / aqueous state. The on duration may be repeated, and an off duration may be allocated between the on durations, and this off duration may mean a WUR off / dose state. On duration may be referred to as an on cycle, and off duration may be indicated as an off cycle.

The WUR STA may receive information on the duty cycle of the WUR mode from the AP. In this case, terms such as a start point and a period of the duty cycle may be used, and a specific positional relationship may be the same as that of FIG. 13.

Hereinafter, the WUR beacon will be described.

The WUR beacon may be a frame / packet that can be demodulated through the WUR module 512 described above, and may be a frame including information for maintaining synchronization (eg, time synchronization) between the WUR STA and the AP.

For example, if the WUR module in the WUR STA operates in the off / dose state for a long time, synchronization between the AP and the STA may be lost. Accordingly, in order to maintain synchronization of the WUR STA, the AP preferably transmits the WUR beacon periodically. The WUR Beacon preferably includes a time sync value. On the other hand, WUR beacons can be used for various operations. For example, it may include information on whether there is data allocated to WUR STAs or may include a discovery function.

The WUR Beacon performs an important function for the WUR STA. For example, when the WUR STA loses synchronization, the AP determines that a specific WUR STA is in the WUR on state, but since the WUR STA may be in the WUR off state, maintaining synchronization through the WUR beacon is important.

The information regarding the duty cycle described above and / or the information about the WUR beacon may be determined in various ways. For example, the WUR STA and the AP may negotiate to determine information about the duty cycle and / or information about the WUR beacon. That is, the WUR STA may receive and / or transmit information about the duty cycle and / or information about the WUR beacon through a specific frame (eg, a WUR Parameter Request / Response frame).

The WUR Parameter Request frame described above is an example of a message in which the WUR STA transmits detailed information about the WUR mode to the AP. That is, the WUR Parameter Request frame may include information for negotiating with the AP in advance in order to operate in the WUR mode. The specific name of the frame can be changed.

The AP may receive a WUR Parameter Request frame and finally determine a parameter related to the WUR mode based on the received content. In addition, the AP may include the finally determined parameter in the WUR Parameter Response frame and transmit the same. When transmission and reception of the WUR Parameter Request / Response is completed, the WUR STA may enter the WUR mode. That is, the WUR STA may enter the WUR mode through the method of FIG. 11, and may transmit and receive a WUR Parameter Request / Response before entering the WUR mode. An example of a WUR Parameter Request / Response frame is described with reference to FIGS. 14 and 15.

14 is an example of a WUR Parameter Request frame. Each field illustrated in FIG. 14 may be changed, and some fields may be omitted.

As shown, the example of FIG. 14 includes an Element ID field and a Length field. In addition, when the WUR STA assigns various modes to all WUR beacons and / or duty cycles, information on the allocated mode may be included in the Duty cycle mode field. In addition, the On duration Length field may include information on how long the WUR STA maintains the WUR on state after receiving the WUR beacon. In addition, the Mode Change delay field may include a delay value applied when the WUR STA switches the WUR on state and / or the PCR on state, or information about a delay value required to turn on / off the PCR module.

15 is an example of a WUR Parameter Response frame. Each field shown in FIG. 15 may be changed, and some fields may be omitted.

As shown, the example of FIG. 15 includes an Element ID field and a Length field. In addition, the Timestamp field of FIG. 15 may include information about an absolute time when the frame of FIG. 15 is transmitted. That is, the Timestamp field may be used to maintain synchronization between the WUR STA and the AP. The WUR Beacon period field of FIG. 15 may include information about a transmission period of a WUR beacon. The duty cycle mode field of FIG. 15 may correspond to the duty cycle mode field of FIG. 14.

The WUR Beacon time field of FIG. 15 may include information about a time value at which the next WUR Beacon is transmitted. The STA group field of FIG. 15 may include information about an identifier of a corresponding group when the WUR STAs are grouped for various purposes.

Individual information shown in FIGS. 14 and 15 may be included in frames other than WUR Parameter Request / Response. In addition, although the corresponding information may be transmitted and received before the WUR STA enters the WUR mode, the corresponding information may be transmitted and received even after entering the WUR mode.

Meanwhile, the WUR STA of the present specification may operate according to a frequency division multiple access (FDMA) technique.

16 is a diagram illustrating a WUR FDMA technique in which a WUR STA operates.

As shown in FIG. 16, the WUR STA may receive a WUR frame through various frequency channels. For example, each channel may have a bandwidth of 20 MHz. In this case, the WUR frame received through each channel may include L-SIG, L-STF, and L-LTF. L-SIG, L-STF, L-LTF (i.e., L-Part) may be configured in a conventional manner for backward compatibility. That is, the L-Part may be received through the 20 MHz band according to the conventional OFDM technique rather than the OOK technique. The L-Part may correspond to the L-SIG, L-STF, and L-LTF 610 of FIG. 6.

The WUR-Part following the L-Part may be configured according to the OOK technique as described above, and may have only a limited number of subcarriers (eg, 13) as shown in FIGS. 6 to 9. It can be configured through.

The WUR STA may receive the WUR frame on all four channels shown in FIG. 16, but may be configured to receive the WUR frame only on any one channel. In addition, the WUR frame may be received only in the first channel at a specific time point, and WUR frame may be received only in the second channel at a later time.

17 is an additional diagram illustrating a WUR FDMA technique with WUR STA operation.

In the example of FIG. 17, the WUR STA may receive a WUR frame in one operating channel. In the example of FIG. 17, the first channel is allocated to the WUR STA1, and the WUR ST1 may receive the WUR frame only through the first channel. The first channel may be represented as an operating channel or a basic operating channel of the WUR STA1.

Hereinafter, the relationship between the FDMA operation and the WUR beacon described above will be described.

The WUR STA may be transmitted / received through only one of a plurality of channels defined in WUR FDMA (for example, four channels are defined in FIGS. 16/17). For example, when a WUR beacon is transmitted and received on a first channel on FDMA, the first channel may be received through a primary channel through which a conventional beacon (ie, a beacon for a PCR module) is received. That is, the WUR channel and the PCR channel may be set identically, and the WUR beacon and the conventional beacon (ie, the PCR beacon) may be received through the same channel.

Alternatively, the WUR channel and the PCR channel may be set differently, and each beacon may be received through different channels.

Meanwhile, a time point at which the WUR beacon is received may be called a target WUR beacon transmission time (TWBTT) and may be transmitted to the WUR STA through a frame of various formats. That is, as the conventional PCR beacon is defined according to the TBTT time point and the TBTT related information is transmitted to the conventional WLAN STA, the TWBTT related information may be delivered to the WUR STA in various ways.

The WUR beacon may be defined to be received only on a primary channel (ie, primary 20 MHz channel) among a plurality of channels defined on FDMA. If the WUR beacon is received only in the primary channel, it is not necessary to set the channel position for receiving the WUR beacon separately, it is possible to communicate efficiently. The position of the primary channel among the plurality of channels may be fixed in advance between WUR STAs / APs or may be variably set through signaling.

18 shows an example of a WUR Beacon frame received over a primary channel. As shown in FIG. 18, the WUR Beacon frame is received via P20 (ie, primary channel). In addition, the WUR beacon frame may include a L-Part having a bandwidth of 20 MHz and a WUR beacon part including information on time synchronization according to a conventional OFDM technique, and the WUR beacon part is configured by the OOK technique. Can be modulated and transmitted / received over only some subcarriers (e.g. 13).

As shown in FIG. 18, when the WUR beacon is received only on the primary channel, a WUR STA operating on another channel (eg, Secondary 20 MHz or Secondary 40 MHz) based on the FDMA scheme does not receive the WUR beacon. May occur. Accordingly, the WUR STA may move to the primary channel through which the WUR Beacon is received (ie, change the reception channel) immediately before the TWBTT.

If the WUR STA normally receives the WUR beacon on the TWBTT, after receiving the WUR beacon, the WUR STA may move to the original WUR operating channel and wait for the WUP through the corresponding WUR operating channel.

If the WUR STA does not normally receive the WUR beacon on the TWBTT, one of the following cases may occur.

Case-A1: The WUR beacon may have already been transmitted because the WUR STA and the AP are out of synchronization. However, very little synchronization occurs with recent chipset technology of STA and AP. Accordingly, the WUR STA may set a guard time that is preset (or dynamically signaled) than the TWBTT, and change the channel in advance by the guard time.

Case-A2: A Medium (ie, wireless channel) may be busy so that the AP has not yet transmitted the WUR beacon. Considering the recent communication environment, the probability of occurrence of Case-A2 is high. If the WUR STA waits to receive the WUR Beacon, the above problem is solved.

In view of the above, the present specification provides a WUR STA capable of receiving WUR frames over multiple channels based on the FDMA scheme so that a WUR beacon normally receives a WUR beacon (for example, waiting time or WUR Beacon Waiting Time). Propose the concept of.

For example, the above-described WUR Beacon Waiting Time may be information about a maximum value of a waiting time for the WUR STA to wait for reception of a WUR beacon. The WUR Beacon Waiting Time may be obtained by the WUR STA based on various schemes. For example, the WUR Beacon Waiting Time may be negotiated in advance between the AP and the STA, or may be signaled by the AP, or may be determined in advance and known between the AP / STA.

On the other hand, since the AP does not know whether the WUR STA has successfully received the WUR beacon, a rule about channel movement between the WUR STA and the AP may be defined in advance. For example, the present specification proposes to always move to the original WUR operating channel after operating on the WUR Beacon transmission channel until the WUR Beacon Waiting Time regardless of whether the WUR STA has received the WUR beacon.

An example of a specific operation at the AP is as follows. Since not all specific examples below are essential, only some features of the following examples may be performed by the AP.

Operation A1: A WUR Beacon frame is periodically transmitted only on a specific channel (eg, a primary channel).

Operation A2: The WUR Beacon frame transmission channel is informed to UEs in advance during WUR mode signaling, scanning, or association.

Operation A3: When transmitting a Wakeup frame (ie, WUP) after transmitting a WUR Beacon frame, the following rules are followed.

Operation A3-1: After the WUR Beacon Waiting Time, the WUP may be transmitted in a channel allocated to each terminal (eg, a secondary 20/40 MHz channel).

Operation A3-2: Before the WUR Beacon Waiting Time, a WUP may be transmitted in a WUR Beacon frame transmission channel by ignoring a channel allocated to each terminal.

An example of a specific operation in the WUR-STA is as follows. Since not all specific examples below are essential, it is possible that only some features of the following examples are performed by the WUR-STA.

Operation B1: During WUR basic operation, the WUP can be received only on the assigned channel (eg, a secondary 20/40 MHz channel).

Operation B2: At the time of TWBTT or at a guard time earlier than TWBTT, the WUR Beacon transmission channel (e.g., Primary channel) is received from the WUR primary operation channel (e.g., Secondary 20/40 MHz channel) to receive WUR Beacon. Can wait.

Operation B2-1: If the WUR basic operation channel and the WUR Beacon transmission channel are the same, channel movement is skipped in the WUR STA, and reception operation is continuously performed in the original channel.

Operation B3: The WUR-STA may move back to the WUR basic operation channel after the WUR Beacon Waiting Time regardless of whether a WUR Beacon frame is received.

Operation B3-1: If the WUR-STA receives the WUP before the WUR Beacon Waiting Time, the WUR-STA receives downlink data (DL Data) from the AP through the PCR module. After receiving all DL data, the WUR operation can be started in the WUR basic operation channel.

19 is a diagram illustrating an example of transmitting / receiving a WUR beacon according to an example of the present specification. Each WUR STA shown in FIG. 19 has a capability of supporting WUR FDMA operation and operates in a WUR mode. That is, the WUR STA of the example of FIG. 19 may enter a WUR mode by the example of FIG. 11 or the like. In the example of FIG. 19, two WUR STAs are proposed, but the number of WUR STAs may be changed. In addition, in the example of 19, two channels based on the WUR FDMA scheme have been proposed, but the number of channels can be changed. In addition, channel 1 of FIG. 19 may be a channel through which the WUR beacon is transmitted / received, that is, a primary channel.

In the example of FIG. 19, channel 2 may already be allocated to the WUR STA 1 as an operation channel. That is, the WUR STA 1 may be configured to receive a WUR frame through channel 2. Accordingly, the WUR STA 1 may receive another WUR frame except for the WUR beacon through the channel 2 1905. Thereafter, at the time of TWBTT, the AP may transmit the WUR beacon 1910. In this case, it is preferable that the WUR STA 1 perform a reception operation on the channel 1 from the TWBTT to the WUR Beacon Waiting Time 1920. That is, the WUR STA1 may move to channel 1 and wait for reception of the WUR beacon 1910. After the WUR Beacon Waiting Time 1920, the WUR STA1 may move to the original operating channel (ie, channel 2) and perform subsequent operations regardless of whether the WUR beacon 1910 is received. That is, the WUR STA1 may receive a WUR frame through the channel 2 1925 after the WUR Beacon Waiting Time 1920. Since the next WUR beacon 1930 may be received in the next TWBTT, the WUR STA 1 may repeat the operation of moving to the channel 1 1935 again.

In the example of FIG. 19, channel 1 may already be allocated to the WUR STA 2 as an operation channel. In this case, the WUR STA 2 may receive the WUR beacons 1910 and 1930 and other WUR frames through the channel 1 because it is not necessary to change the channel for the reception of the WUR beacons 1910 and 1930.

In FIG. 19, an operation of moving the WUR STA 1 to channel 1 at the time of TWBTT has been described for convenience of description. However, as described above, the WUR STA1 may move to the channel 1 in advance as a guard time.

Referring to the operation of FIG. 19 from the perspective of the AP, the AP may allocate an operation channel to each WUR STA in advance. That is, the AP may set channel 2 as an operating channel for WUR STA 1 and set channel 1 as an operating channel for WUR STA 2. Thereafter, the AP may not transmit a WUR frame on channel 2 during the WUR Beacon Waiting Time after TWBTT.

20 is a diagram illustrating an additional example of transmitting / receiving a WUR beacon according to an example of the present specification. The technical features applied to FIG. 19 apply equally to the example of FIG. 20. For convenience of description, descriptions of overlapping technical features will be omitted.

In the example of FIG. 20, WUR beacons 2010 and 2030 are transmitted based on the TWBTT time point. In the example of FIG. 20, the first WUP 2012 for the WUR STA 1 may be transmitted during the WUR Beacon Waiting Time 2020. In this case, the first WUP 2012 is preferably transmitted through channel 1. That is, the first WUP 2012 is transmitted through the channel 1 during the time period during which the WUR STA 1 performs the reception on the channel 1. Meanwhile, even after the WUR Beacon Waiting Time 2020, the first WUP 2012 for the WUR STA 1 may be transmitted. In this case, it is preferable that the first WUP 2012 is transmitted through channel 2 2025, which is an operating channel of WUR STA 1.

According to the example of the present specification as described above, an additional operation may be required in which the WUR STA needs to move a channel (that is, change a reception channel). However, this can achieve the technical effect of simply arranging the channel to which the WUR beacon is transmitted / received. That is, one example of the present specification may solve a problem that occurs when the WUR beacon is transmitted / received on various channels. In addition, since the WUR beacon is transmitted on the same channel for all WUR STAs, there is a technical effect that the probability of receiving the WUR beacons by several WUR STAs can be maintained / managed constantly.

Since the aforementioned WUR Beacon Waiting Time affects performance, the UE and the AP may be determined through consensus / negotiation. When the UE and the AP exchange WUR capability information, the UE and the AP may include the following additional information for determining the WUR Beacon Waiting Time. Since the following additional information corresponds to an example, the following information may be omitted or partially included.

Information 1: The Maximum WUR Beacon Waiting Time field may be included. It includes information on the maximum value of the WUR Beacon Waiting Time for the UE or AP to operate.

Information 2: The Minimum WUR Beacon Waiting Time field may be included. Includes information on the minimum value of the WUR Beacon Waiting Time for the UE or AP to operate. The WUR Beacon Waiting Time value to be operated is determined between the Max and Min values above.

Info 3: Preferred WUR Beacon Waiting Time field may be included. The UE or the AP may determine and inform the appropriate WUR Beacon Waiting Time value to the UE. The terminal or the AP that receives this may use the value as it is, but may adjust it if necessary.

Information 3: The Channel Switch Delay field may be included. This is a time delay value required when the terminal or the AP changes the channel. This can be used to determine the WUR Beacon Waiting Time.

Information 4: The Preferred WUR Channel field may be included. When FDMA operation, the channel can be selected in advance.

19 and 20 correspond to an example of the present specification, so the example of FIG. 19/20 may be variously changed. For example, while maintaining the technical features of FIG. 19/20, the AP may be allowed to transmit a WUP on both channel 1 and channel 2 during the WUR Beacon Waiting Time. In this case, the WUR STA may move to an operation channel assigned to the WUR STA without having to maintain reception of channel 1 during the WUR Beacon Waiting Time. Additionally or alternatively, an example of setting the length of the WUR on duration to be equal to the WUR Beacon Waiting Time may be possible while maintaining the technical features of FIG. 19/20. In this case, there is an advantage that the WUR Beacon Waiting Time is set through a method of signaling a WUR on duration previously proposed, without having to transmit / receive information on the WUR Beacon Waiting Time through additional signaling.

In addition, the following technical features may be applied to the example of FIG. 19 / FIG. 20. For example, the WUR on duration (ie, the WUR on state) may not be allocated at the time of TWBTT. That is, when the WUR STA and the AP negotiate the length of the WUR on duration, that is, during the negotiation of the WUR duty cycle, it is preferable to perform the negotiation so that the WUR on duration does not overlap with the TWBTT. That is, even if the WUR STA does not operate on the primary channel in the WUR on duration, since the WUR on duration and the TWBTT do not overlap, a malfunction of the WUR STA can be prevented.

21 is a procedure flowchart to which an example of the present invention is applied. 21 illustrates an operation performed in the WUR STA. Operations performed at the AP are described with the example of FIG. 22.

The order of each step in FIG. 21 may be modified. That is, the order of each step illustrated in FIG. 21 is only an example of the present specification. In addition, each step of FIG. 21 is not necessarily performed at different times, and different steps of FIG. 21 may be simultaneously performed in an actual implementation process.

As shown, in step S2110, a WUR STA may transmit information related to WUR capability to an access point (AP). Step S2110 may be performed as part of negotiation between the WUR STA and the AP.

The information related to the WUR capability may include information related to a WUR Frequency Division Multiple Access (FDMA) operation of the WUR STA. That is, the information related to the WUR capability may indicate information about the WUR capability of the WUR STA through a first field, and may indicate information about whether the WUR STA supports WUR FDMA operation through the second field. In addition, the above-described information about the preferred WUR channel may be delivered to the AP through step S2110. The WUR FDMA may support a first channel including a WUR primary channel and a second channel different from the first channel (eg, Secondary 20/40 MHz).

For example, the information transmitted through S2110 may be changed in various ways. For example, the information related to the WUR capability may include information on whether the WUR channel is configured in the 2.4 GHz band or in the 4.9 and 5.0 GHz bands. In addition, the information related to the WUR capability may include information regarding a maximum time taken for the PCR module of the WUR STA and / or the WUR module to transition from the off / dose state to the on / awake state.

As shown in step S2120, the WUR STA may receive first control information related to a transmission time of a WUR beacon from the AP. That is, the first control information may include information about the TWBTT.

Operation S2120 may be implemented by receiving a frame illustrated in FIG. 23.

FIG. 23 is an example of a frame that conveys information about a transmission time of a WUR beacon. The example of FIG. 23 may be included in a MAC PDU and may be decoded by the PCR module of the WUR STA. The frame of FIG. 23 may be received before entering the WUR mode or may only be received after entering the WUR mode. The Element ID, Length, and Element ID Extension fields of FIG. 23 perform a conventional function, and the WUR Parameters field includes additional control information for the WUR field not described below.

The first control information transmitted through the step S2120 may be included in the WUR Operation Parameters field 2310 of FIG. 23. As shown, the WUR Operation Parameters field 2310 includes a Minimum Wake-up Duration field 2320, a Duty Cycle Period Units field 2330, a WUR Operating Class field 2340, a WUR Channel field 2350, and a WUR Beacon Period Field 2360, and Offset of TWBTT field 2370. In detail, the first control information may be included in the Offset of TWBTT field 2370 of FIG. 23.

The minimum wake-up duration field 2320 of FIG. 23 may include information about a minimum value of the WUR on duration, and the Duty Cycle Period Units field 2330 may include information about the duty cycle period illustrated in FIG. 23. The WUR Operating Class field 2340 may include information regarding a predefined WUR operating class, and the WUR Channel field 2350 may include information for defining a channel through which a WUR beacon is transmitted or another WUR channel. , WUR Beacon Period field 2360 may include information about a transmission period of the WUR beacon.

As illustrated, in step S2130, the WUR STA may acquire second control information related to a waiting time related to the WUR beacon. The waiting time may be called various names, for example, may be called WUR Beacon Waiting Time. The WUR STA may perform step S2120 by applying a fixed time value or may perform step S2130 by receiving a specific time value from an AP or other entity.

Although not shown in FIG. 21, the WUR STA may receive information about an operation channel (or the second channel) from the AP. In more detail, the AP may transmit a WUR channel offset field to the WUR STA to indicate an operating channel (eg, channel 2 of FIG. 19) allocated for the WUR STA. The WUR channel offset field may include information about channel offset from the primary channel (eg, channel 1 of FIG. 19).

As illustrated, in step S2140, the WUR STA may receive a WUR packet through the first channel and / or the second channel. The step S2140 may be based on the example of FIG. 19/20. That is, the WUR STA may stop reception through the second channel during a waiting time from TWBTT. In terms of an AP, the AP does not transmit any WUR frame on a second channel (eg, Secondary 20/40 MHz) during a waiting time from TWBTT.

Receipt of step S2140 may be interpreted as meaning of decoding. That is, the WUR STA may stop decoding the received signal on the second channel during the waiting time from the TWBTT.

22 is a flowchart illustrating an example of the present invention applied to an AP. Step S2210 of FIG. 22 corresponds to step S2110 of FIG. 21. In addition, step S2220 of FIG. 22 corresponds to step S2120 of FIG. 21. In addition, step S2230 of FIG. 22 corresponds to step S2140 of FIG. 21.

24 shows an example of a terminal to which an example of the present specification is applied.

Referring to FIG. 24, the STA 2400 includes a processor 2410, a memory 2420, and a transceiver 2430. 24 may be applied to a non-AP STA or an AP STA. The illustrated processor, memory, and transceiver may be implemented as separate chips, or at least two blocks / functions may be implemented through one chip.

The illustrated transceiver 2430 performs a signal transmission and reception operation. In detail, the WUR packet and / or the IEEE 802.11 packet may be transmitted and received.

The processor 2410 may implement the functions, processes, and / or methods proposed herein. In detail, the processor 2410 may receive a signal through the transceiver 2430, process a received signal, generate a transmission signal, and perform control for signal transmission.

Such a processor 2410 may include an application-specific integrated circuit (ASIC), another chipset, a logic circuit, and a data processing device. The memory 2420 may include read-only memory (ROM), random access memory (RAM), flash memory, memory card, storage medium, and / or other storage device.

The memory 2420 may store a signal (ie, a received signal) received through the transceiver, and store a signal (ie, a transmission signal) to be transmitted through the transceiver. That is, the processor 2410 may acquire the received signal through the memory 2420, and store the signal to be transmitted in the memory 2420.

25 shows another example of a detailed block diagram of a transceiver. Some or all of the blocks of FIG. 25 may be included in the processor 2410. Referring to FIG. 25, the transceiver 110 includes a transmitting part 111 and a receiving part 112. The transmission part 111 includes a discrete fourier transform (DFT) unit 1111, a subcarrier mapper 1112, an IFFT unit 1113, a CP insertion unit 1144, and a wireless transmitter 1115. The transmission part 111 may further include a modulator. Further, for example, the apparatus may further include a scramble unit (not shown), a modulation mapper (not shown), a layer mapper (not shown) and a layer permutator (not shown). It may be disposed before the DFT unit 1111. That is, in order to prevent an increase in peak-to-average power ratio (PAPR), the transmission part 111 first passes the information through the DFT 1111 before mapping a signal to a subcarrier. After subcarrier mapping of the signal spread (or precoded in the same sense) by the DFT unit 1111 through the subcarrier mapper 1112, the inverse fast fourier transform (IFFT) unit 1113 is again passed on the time axis. Make it a signal.

The DFT unit 1111 outputs complex-valued symbols by performing a DFT on the input symbols. For example, when Ntx symbols are input (where Ntx is a natural number), the DFT size is Ntx. The DFT unit 1111 may be called a transform precoder. The subcarrier mapper 1112 maps the complex symbols to each subcarrier in the frequency domain. The complex symbols may be mapped to resource elements corresponding to resource blocks allocated for data transmission. The subcarrier mapper 1112 may be called a resource element mapper. The IFFT unit 1113 performs an IFFT on the input symbol and outputs a baseband signal for data, which is a time domain signal. The CP inserter 1114 copies a part of the rear part of the base band signal for data and inserts it in the front part of the base band signal for data. Inter-symbol interference (ISI) and inter-carrier interference (ICI) can be prevented through CP insertion to maintain orthogonality even in multipath channels.

On the other hand, the receiving part 112 includes a radio receiver 1121, a CP remover 1122, an FFT unit 1123, an equalizer 1124, and the like. The wireless receiving unit 1121, the CP removing unit 1122, and the FFT unit 1123 of the receiving part 112 include a wireless transmitting unit 1115, a CP insertion unit 1114, and an IFF unit 1113 at the transmitting end 111. It performs the reverse function of). The receiving part 112 may further include a demodulator.

In addition to the illustrated block, the transceiver of FIG. 25 may include a reception window controller (not shown) for extracting a part of a received signal, and a decoding operation processor (not shown) for performing a decoding operation on a signal extracted through the reception window. ) May be included.

Claims (12)

 A method for a wireless local area network (WLAN) system, the method comprising: WUR STA (station) comprising a main radio receiver for receiving a wireless LAN packet and a wake-up radio (WUR) receiver for receiving a wake-up radio (WUR) packet that is modulated by an on-off keying (OOK) technique, Transmits information related to WUR capability to an access point (AP), wherein the information related to the WUR capability includes information related to a WUR Frequency Division Multiple Access (FDMA) operation of the WUR STA, wherein the WUR FDMA is a WUR Supporting a first channel comprising a primary channel and a second channel different from the first channel; The WUR STA receives first control information related to a transmission time of a WUR beacon from the AP, wherein the WUR beacon is used to maintain synchronization between the WUR STA and the AP, The WUR beacon is received over the first channel; Acquiring, by the WUR STA, second control information related to a waiting time related to the WUR beacon; And The WUR STA receives a WUR packet on the first channel and / or the second channel, and the WUR STA stops receiving on the second channel for the waiting time after the transmission time of the WUR beacon, step How to include. The method of claim 1, The WUR STA operates based on a WUR mode to receive the WUR beacon, where the WUR module alternates between a WUR on state and a WUR doze state. That is, Way. The method of claim 2, The information on the duty cycle of the WUR mode is determined based on negotiation between the WUR STA and the AP, The time interval of the negotiated WUR on state does not overlap the transmission time point of the WUR beacon. Way. The method of claim 1, Receiving, from the AP, information indicating that the AP uses the second channel Containing more Way. The method of claim 1, The WUR Beacon is modulated based on the OOK technique Way. In a station in a wireless local area network (WLAN) system, A main radio module for receiving a WLAN packet; A wake-up radio (WUR) module for receiving a wake-up radio (WUR) packet that is modulated by an on-off keying (OOK) technique; And Including a processor including the main radio module and a WUR (Wake-Up Radio) module, The processor is: Transmits information related to WUR capability to an access point (AP), wherein the information related to the WUR capability includes information related to a WUR Frequency Division Multiple Access (FDMA) operation of the WUR STA, wherein the WUR FDMA is a WUR Support a first channel including a primary channel and a second channel different from the first channel, Receive first control information related to a transmission time of a WUR beacon from the AP, wherein the WUR beacon is used to maintain synchronization between the WUR STA and the AP, and the WUR beacon is Received over the first channel, Obtaining second control information related to a waiting time related to the WUR beacon, Receives a WUR packet through the first channel and / or the second channel, wherein the WUR STA is configured to stop reception through the second channel for the waiting time after the transmission time of the WUR beacon. Device The method of claim 6, The processor operates based on a WUR mode to receive the WUR beacon, where the WUR module alternates between a WUR on state and a WUR doze state. Segment, Device. The method of claim 7, wherein The information on the duty cycle of the WUR mode is determined based on negotiation between the STA and the AP, The time interval of the negotiated WUR on state does not overlap the transmission time point of the WUR beacon. Device. The method of claim 6, The processor receives from the AP information indicating that the AP uses the second channel. Device. The method of claim 6, The WUR Beacon is modulated based on the OOK technique Device. A method for a wireless local area network (WLAN) system, the method comprising: It includes a main radio receiver for receiving a WLAN packet by an access point (AP) and a wake-up radio receiver for receiving a wake-up radio (WUR) packet that is modulated by an on-off keying (OOK) technique. Receive information related to WUR capability from a WUR STA, wherein the information related to the WUR capability includes information related to a WUR Frequency Division Multiple Access (FDMA) operation of the WUR STA, wherein the WUR FDMA Supporting a first channel comprising a WUR Primary channel and a second channel different from the first channel; The AP transmits first control information related to a transmission time of a WUR beacon to the WUR STA, wherein the WUR beacon maintains synchronization between the WUR STA and the AP. Used, wherein the WUR beacon is transmitted on the first channel; And The WUR packet is transmitted by the AP through the first channel and / or the second channel, and the WUR packet for the WUR STA is transmitted during the waiting time after the AP transmits the WUR beacon. Not sent via, steps How to include. The method of claim 11, The WUR Beacon is modulated based on the OOK technique Way.

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