WO2018143580A1

WO2018143580A1 - Method and apparatus for transmitting wake-up packet in wireless lan system

Info

Publication number: WO2018143580A1
Application number: PCT/KR2018/000719
Authority: WO
Inventors: 박은성; 임동국; 최진수
Original assignee: 엘지전자 주식회사
Priority date: 2017-01-31
Filing date: 2018-01-16
Publication date: 2018-08-09

Abstract

A method and apparatus for transmitting a wake-up frame to a wireless LAN system are proposed. Specifically, a transmission apparatus configures a PPDU to which a first wireless LAN system is applied. The transmission apparatus transmits a wake-up frame to which the second wireless LAN system is applied, through the PPDU. The PPDU comprises a signal field and a data field. The data field is transmitted through at least one RU corresponding to a first frequency band indicated by the signal field. The wake-up frame is transmitted through a center 26-RU positioned at the center of a second frequency band included in the first frequency band. An OOK method is applied to the wake-up frame and thus the wake-up frame consists of an ON signal and an OFF signal. The ON signal applies a first sequence to 13 consecutive subcarriers in the 20 MHz band, by performing 64-point IFFT delivers through a generated ON symbol.

Description

Method and apparatus for transmitting wake-up packet in WLAN system

The present disclosure relates to a technique for performing low power communication in a WLAN system, and more particularly, to a method and apparatus for transmitting a wake-up packet using an HE PPDU in a WLAN system.

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 the next-generation WLAN, there is a great interest in scenarios such as wireless office, smart home, stadium, hotspot, building / apartment, and AP based on the scenario. And STA are discussing about improving system performance in a dense environment with many STAs.

In addition, in the next-generation WLAN, there will be more discussion about improving system performance in outdoor overlapping basic service set (OBSS) environment, improving outdoor environment performance, and cellular offloading, rather than improving single link performance in one basic service set (BSS). It is expected. The directionality of these next-generation WLANs means that next-generation WLANs will increasingly have a technology range similar to that of mobile communications. Considering the recent situation in which mobile communication and WLAN technology are discussed together in the small cell and direct-to-direct (D2D) communication area, the technical and business convergence of next-generation WLAN and mobile communication is expected to become more active.

The present specification proposes a method and apparatus for transmitting a wake-up packet using an HE PPDU in a WLAN system.

An example of the present specification proposes a method and apparatus for transmitting a wake-up frame using an HE-PPDU in a WLAN system.

The present embodiment may be performed in a network environment in which the first WLAN system and the second WLAN system are supported together. Here, the first WLAN system may correspond to the 802.11ax system, and the second WLAN system may correspond to the 802.11ba system.

The present embodiment may be performed in a transmitting apparatus, and a receiving apparatus supporting the first WLAN system may correspond to an ax STA, and a receiving apparatus supporting the second WLAN system may correspond to a low power wake-up receiver or a WUR STA. . The transmitter may correspond to the AP.

First of all, the term “on signal” may correspond to a signal having an actual power value. The off signal may correspond to a signal that does not have an actual power value.

A physical layer protocol data unit (PPDU) to which the first WLAN system is applied is configured.

The transmitter transmits a wake-up frame to which the second WLAN system is applied through the PPDU.

The PPDU includes a signal field and a data field. The signal field is a control information field of the PPDU and may correspond to a HE-SIG-B field. The HE-SIG-B field may be included only when it is a PPDU for multiple users (MU). Basically, the HE-SIG-B may include resource allocation information for at least one receiver.

Accordingly, the data field is transmitted through at least one radio unit (RU) corresponding to the first frequency band indicated by the signal field. For example, if the first frequency band is 20 MHz, 40 MHz, or 80 MHz, at least one RU corresponding to the first frequency band is 26-RU, 52-RU, 106-RU (or 242-RU, aggregated). 484-RU, 996-RU)

The wakeup frame may be transmitted through a center 26-RU located at the center of a second frequency band included in the first frequency band.

According to the first frequency band and the second frequency band, the center 26-RU in which the wake-up frame is transmitted may be allocated as follows.

For example, the first frequency band may be a primary 20MHz, and the second frequency band may be the primary 20MHz. Alternatively, the first frequency band may be a primary 40MHz, the second frequency band may be each 20MHz within the primary 40MHz. Alternatively, the first frequency band may be a primary 80MHz, the second frequency band may be each 20MHz in the primary 80MHz. Alternatively, the first frequency band may be 80 + 80 MHz or 160 MHz, and the second frequency band may be 20 MHz within the 80 + 80 MHz or 160 MHz.

The example illustrates a case in which the wakeup frame is transmitted using only the central 26-RU of 20 MHz. The central 26-RU of each 20 MHz may be allocated based on an identifier (ID) of a receiving apparatus supporting the second WLAN system. Specifically, the central 26-RU of each 20MHz may be distinguished using a modulo value of an identifier of the receiver supporting the second WLAN system.

As another example, the first frequency band may be 80 + 80 MHz or 160 MHz, and the second frequency band may be a primary 80 MHz or a secondary 80 MHz.

The example illustrates a case where the wakeup frame is transmitted using only the center 26-RU of 80 MHz. The central 26-RU of the primary 80 MHz or the secondary 80 MHz may be allocated based on the signal field supporting the second WLAN system. Specifically, when the center 26-tone RU subfield of the common field included in the signal field indicates 0, the wakeup frame may be transmitted using the center 26-RU of 80 MHz. If the center 26-tone RU subfield indicates 1, the wake-up frame cannot use the center 26-RU of 80 MHz.

As another example, the first frequency band may be 80 MHz, and the second frequency band may be 20 MHz and 80 MHz, respectively, within the 80 MHz.

The example illustrates a case in which the wake-up frame is transmitted using both a center 26-RU of 20 MHz and a center 26-RU of 80 MHz. Each of the central 26-RU of 20 MHz and the central 26-RU of 80 MHz may be allocated based on an identifier (ID) of a receiver supporting the second WLAN system. Specifically, the central 26-RU of each 20MHz and the central 26-RU of the 80MHz may be distinguished using a modulo value of an identifier of the receiver supporting the second WLAN system.

As a last example, the first frequency band may be 80 + 80 MHz or 160 MHz, and the second frequency band may be 20 MHz, primary 80 MHz, and secondary 80 MHz within the 80 + 80 MHz or 160 MHz.

The example illustrates a case in which the wake-up frame is transmitted using both a center 26-RU of 20 MHz and a center 26-RU of 80 MHz. The center 26-RU of each 20 MHz, the center 26-RU of the primary 80 MHz, and the center 26-RU of the secondary 80 MHz may be allocated based on an identifier (ID) of a receiver supporting the second WLAN system. have. Specifically, the central 26-RU of each 20MHz and the central 26-RU of the 80MHz may be distinguished using a modulo value of an identifier of the receiver supporting the second WLAN system.

In addition, the data field may be transmitted to the receiving apparatus supporting the first WLAN system through the at least one RU. The wakeup frame may be transmitted to a receiving device supporting the second WLAN system through the central 26-RU. That is, the central 26-RU may not be allocated to a receiving device supporting the first WLAN system, but may be allocated only to a receiving device supporting the second WLAN system.

In addition, the data field and the wake-up frame may be transmitted simultaneously. That is, the data field and the wake-up frame may be simultaneously transmitted through different frequency bands through the OFDMA technique.

The wakeup frame may not be transmitted through the center 26-RU of the second frequency band, but may be transmitted using a Long Training Field (LTF) sequence for the second frequency band.

According to the exemplary embodiment of the present specification, the wakeup packet is configured and transmitted by applying the OOK modulation scheme in the transmitter to reduce power consumption by using an envelope detector during wakeup decoding in the receiver. Therefore, the receiving device can decode the wakeup packet to the minimum power.

In addition, resource efficiency may be maximized by transmitting a wakeup packet using an RU not allocated to a receiver supporting 802.11ax, and the transmitter may simultaneously transmit a wakeup packet together with the HE PPDU.

1 is a conceptual diagram illustrating a structure of a wireless local area network (WLAN).

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

3 is a diagram illustrating an example of a HE PPDU.

4 is a diagram illustrating an arrangement of resource units (RUs) used on a 20 MHz band.

5 is a diagram illustrating an arrangement of resource units (RUs) used on a 40 MHz band.

6 is a diagram illustrating an arrangement of resource units (RUs) used on an 80 MHz band.

7 is a diagram illustrating another example of the HE-PPDU.

8 is a block diagram showing an example of the HE-SIG-B according to the present embodiment.

9 shows an example of a trigger frame.

10 illustrates an example of subfields included in a per user information field.

11 is a block diagram showing an example of a control field and a data field constructed according to the present embodiment.

12 shows an example of this embodiment for a 40 MHz transmission.

13 shows an example in which the present specification is applied to an 80 MHz transmission.

14 shows an example in which the control signal is modified according to the present specification.

15 shows a further example of modification of the control signal in accordance with the present specification.

16 illustrates an example in which the control signal and frequency mapping relationship are modified according to the present specification.

17 illustrates an example in which the control signal and frequency mapping relationship are modified according to the present specification.

18 illustrates a further example of a control signal and frequency mapping relationship in accordance with the present disclosure.

Fig. 19 is a diagram showing a relationship between SIG-A, SIG-B and data fields according to the present embodiment.

20 is a diagram illustrating an example of SIG-B used for 80 MHz transmission.

21 illustrates a low power wake-up receiver in an environment in which data is not received.

22 illustrates a low power wake-up receiver in an environment in which data is received.

23 shows an example of a wakeup packet structure according to the present embodiment.

24 shows signal waveforms of the wakeup packet according to the present embodiment.

FIG. 25 is a diagram for describing a principle in which power consumption is determined according to a ratio of 1 and 0 of bit values constituting binary sequence information using the OOK method.

26 shows a method of designing a OOK pulse according to the present embodiment.

27 is an explanatory diagram for Manchester coding technique according to the present embodiment.

28 illustrates various examples of a symbol repetition technique of repeating n symbols according to the present embodiment.

29 shows various examples of a symbol reduction technique according to the present embodiment.

30 is a flowchart illustrating a procedure of transmitting a wake-up frame using the HE-PPDU according to the present embodiment.

31 is a block diagram illustrating a wireless device to which the present embodiment can be applied.

1 shows the structure of the infrastructure basic service set (BSS) of the Institute of Electrical and Electronic Engineers (IEEE) 802.11.

Referring to the top of FIG. 1, the WLAN system may include one or more infrastructure BSSs 100 and 105 (hereinafter, BSS). The BSSs 100 and 105 are a set of APs and STAs such as an access point 125 and a STA1 (station 100-1) capable of successfully synchronizing and communicating with each other, and do not indicate a specific area. The BSS 105 may include one or more joinable STAs 105-1 and 105-2 to one AP 130.

The BSS may include at least one STA, APs 125 and 130 for providing a distribution service, and a distribution system (DS) 110 for connecting a plurality of APs.

The distributed system 110 may connect several BSSs 100 and 105 to implement an extended service set (ESS) 140 which is an extended service set. The ESS 140 may be used as a term indicating one network in which one or several APs 125 and 230 are connected through the distributed system 110. APs included in one ESS 140 may have the same service set identification (SSID).

The portal 120 may serve as a bridge for connecting the WLAN network (IEEE 802.11) with another network (for example, 802.X).

In the BSS as shown in the upper part of FIG. 1, a network between the APs 125 and 130 and a network between the APs 125 and 130 and the STAs 100-1, 105-1 and 105-2 may be implemented. However, it may be possible to perform communication by setting up a network even between STAs without the APs 125 and 130. A network that performs communication by establishing a network even between STAs without APs 125 and 130 is defined as an ad-hoc network or an independent basic service set (BSS).

1 is a conceptual diagram illustrating an IBSS.

Referring to the bottom of FIG. 1, the IBSS is a BSS operating in an ad-hoc mode. Since IBSS does not contain an AP, there is no centralized management entity. That is, in the IBSS, the STAs 150-1, 150-2, 150-3, 155-4, and 155-5 are managed in a distributed manner. In the IBSS, all STAs 150-1, 150-2, 150-3, 155-4, and 155-5 may be mobile STAs, and access to a distributed system is not allowed, thus making a self-contained network. network).

A STA is any functional medium that includes 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. May be used to mean both an AP and a non-AP STA (Non-AP Station).

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

On the other hand, the term "user" may be used in various meanings, for example, may also be used to mean an STA participating in uplink MU MIMO and / or uplink OFDMA transmission in wireless LAN communication. It is not limited to this.

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.

3 is a diagram illustrating an example of a HE PPDU.

The control information field proposed in this embodiment may be HE-SIG-B included in the HE PPDU as shown in FIG. 3. The HE PPDU according to FIG. 3 is an example of a PPDU for multiple users. The HE-SIG-B may be 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.).

Detailed description of each field of FIG. 3 will be described later.

As shown in FIG. 4, resource units (RUs) corresponding to different numbers of tones (ie, subcarriers) may be used to configure some fields of the HE-PPDU. For example, resources may be allocated in units of RUs shown for HE-STF, HE-LTF, and data fields.

As shown at the top of FIG. 4, 26-units (ie, units corresponding to 26 tones) may be arranged. Six tones may be used as the guard band in the leftmost band of the 20 MHz band, and five tones may be used as the guard band in the rightmost band of the 20 MHz band. In addition, seven DC tones are inserted into the center band, that is, the DC band, and 26-units corresponding to each of the 13 tones may exist to the left and right of the DC band. In addition, other bands may be allocated 26-unit, 52-unit, 106-unit. Each unit can be assigned for a receiving station, i. E. A user.

On the other hand, the RU arrangement of FIG. 4 is utilized not only for the situation for a plurality of users (MU), but also for the situation for a single user (SU), in which case one 242-unit is shown as shown at the bottom of FIG. It is possible to use and in this case three DC tones can be inserted.

In the example of FIG. 4, various sizes of RUs have been proposed, that is, 26-RU, 52-RU, 106-RU, 242-RU, and the like. Since the specific sizes of these RUs can be expanded or increased, the present embodiment Is not limited to the specific size of each RU (ie, the number of corresponding tones).

Just as RUs of various sizes are used in the example of FIG. 4, the example of FIG. 5 may also use 26-RU, 52-RU, 106-RU, 242-RU, 484-RU, and the like. In addition, five DC tones can be inserted at the center frequency, 12 tones are used as the guard band in the leftmost band of the 40 MHz band, and 11 tones are in the rightmost band of the 40 MHz band. This guard band can be used.

Also, as shown, the 484-RU may be used when used for a single user. Meanwhile, the specific number of RUs may be changed as in the example of FIG. 4.

Just as RUs of various sizes are used in the example of FIGS. 4 and 5, the example of FIG. 6 may also use 26-RU, 52-RU, 106-RU, 242-RU, 484-RU, 996-RU, and the like. have. In addition, seven DC tones can be inserted in the center frequency, 12 tones are used as the guard band in the leftmost band of the 80 MHz band, and 11 tones in the rightmost band of the 80 MHz band. This guard band can be used. Also available is a 26-RU with 13 tones each located to the left and right of the DC band.

Also, as shown, when used for a single user, a 996-RU may be used, in which case five DC tones may be inserted.

Meanwhile, the specific number of RUs may be changed as in the example of FIGS. 4 and 5.

7 is a diagram illustrating another example of the HE-PPDU.

7 is another example illustrating the HE-PPDU block of FIG. 3 in terms of frequency.

The illustrated L-STF 700 may include a short training orthogonal frequency division multiplexing symbol. The L-STF 700 may be used for frame detection, automatic gain control (AGC), diversity detection, and coarse frequency / time synchronization.

The L-LTF 710 may include a long training orthogonal frequency division multiplexing symbol. The L-LTF 710 may be used for fine frequency / time synchronization and channel prediction.

L-SIG 720 may be used to transmit control information. The L-SIG 720 may include information about a data rate and a data length. In addition, the L-SIG 720 may be repeatedly transmitted. That is, the L-SIG 720 may be configured in a repeating format (for example, may be referred to as an R-LSIG).

The HE-SIG-A 730 may include control information common to the receiving station.

Specifically, the HE-SIG-A 730 may include 1) a DL / UL indicator, 2) a BSS color field which is an identifier of a BSS, 3) a field indicating a remaining time of a current TXOP interval, 4) 20, Bandwidth field indicating whether 40, 80, 160, 80 + 80 MHz, 5) field indicating the MCS scheme applied to HE-SIG-B, 6) dual subcarrier modulation for HE-SIG-B field indicating whether it is modulated by dual subcarrier modulation), 7) field indicating the number of symbols used for HE-SIG-B, and 8) indicating whether HE-SIG-B is generated over the entire band. Field, 9) field indicating the number of symbols of the HE-LTF, 10) field indicating the length and CP length of the HE-LTF, 11) field indicating whether additional OFDM symbols exist for LDPC coding, 12) A field indicating control information about a packet extension (PE), and 13) a field indicating information on a CRC field of the HE-SIG-A. have. Specific fields of the HE-SIG-A may be added or omitted. In addition, some fields may be added or omitted in other environments where the HE-SIG-A is not a multi-user (MU) environment.

The HE-SIG-B 740 may be included only when it is a PPDU for a multi-user (MU) as described above. Basically, the HE-SIG-A 750 or the HE-SIG-B 760 may include resource allocation information (or virtual resource allocation information) for at least one receiving STA.

As shown, the HE-SIG-B field includes a common field at the beginning, and the common field can be encoded separately from the following field. That is, as shown in FIG. 8, the HE-SIG-B field may include a common field including common control information and a user-specific field including user-specific control information. In this case, the common field may include a corresponding CRC field and may be coded into one BCC block. Subsequent user-specific fields may be coded into one BCC block, including a "user-feature field" for two users and a corresponding CRC field, as shown.

The previous field of HE-SIG-B 740 on the MU PPDU may be transmitted in duplicated form. In the case of the HE-SIG-B 740, the HE-SIG-B 740 transmitted in a part of the frequency band (for example, the fourth frequency band) is the frequency band of the corresponding frequency band (ie, the fourth frequency band). Control information for a data field and a data field of another frequency band (eg, the second frequency band) except for the corresponding frequency band may be included. In addition, the HE-SIG-B 740 of a specific frequency band (eg, the second frequency band) duplicates the HE-SIG-B 740 of another frequency band (eg, the fourth frequency band). It can be one format. Alternatively, the HE-SIG-B 740 may be transmitted in encoded form on all transmission resources. The field after the HE-SIG-B 740 may include individual information for each receiving STA that receives the PPDU.

The HE-STF 750 may be used to improve automatic gain control estimation in a multiple input multiple output (MIMO) environment or an OFDMA environment.

The HE-LTF 760 may be used to estimate a channel in a MIMO environment or an OFDMA environment.

The size of the FFT / IFFT applied to the field after the HE-STF 750 and the HE-STF 750 may be different from the size of the FFT / IFFT applied to the field before the HE-STF 750. For example, the size of the FFT / IFFT applied to the fields after the HE-STF 750 and the HE-STF 750 may be four times larger than the size of the IFFT applied to the field before the HE-STF 750. .

For example, at least one of L-STF 700, L-LTF 710, L-SIG 720, HE-SIG-A 730, HE-SIG-B 740 on the PPDU of FIG. When a field of s is called a first field, at least one of the data field 770, the HE-STF 750, and the HE-LTF 760 may be referred to as a second field. The first field may include a field related to a legacy system, and the second field may include a field related to a HE system. In this case, the FFT (fast Fourier transform) size / inverse fast Fourier transform (IFFT) size is N times the FFT / IFFT size used in the conventional WLAN system (N is a natural number, for example, N = 1, 2, 4) can be defined. That is, an FFT / IFFT of N (= 4) times size may be applied to the second field of the HE PPDU compared to the first field of the HE PPDU. For example, 256 FFT / IFFT is applied for a bandwidth of 20 MHz, 512 FFT / IFFT is applied for a bandwidth of 40 MHz, 1024 FFT / IFFT is applied for a bandwidth of 80 MHz, and 2048 FFT for a bandwidth of 160 MHz continuous or discontinuous 160 MHz. / IFFT can be applied.

In other words, the subcarrier spacing / subcarrier spacing is 1 / N times the size of the subcarrier space used in the conventional WLAN system (N is a natural number, for example, 78.125 kHz when N = 4). Can be. That is, a subcarrier spacing of 312.5 kHz, which is a conventional subcarrier spacing, may be applied to a first field of the HE PPDU, and a subcarrier space of 78.125 kHz may be applied to a second field of the HE PPDU.

Alternatively, the IDFT / DFT period applied to each symbol of the first field may be expressed as N (= 4) times shorter than the IDFT / DFT period applied to each data symbol of the second field. . That is, the IDFT / DFT length applied to each symbol of the first field of the HE PPDU is 3.2 μs, and the IDFT / DFT length applied to each symbol of the second field of the HE PPDU is 3.2 μs * 4 (= 12.8 μs Can be expressed as The length of an OFDM symbol may be a value obtained by adding a length of a guard interval (GI) to an IDFT / DFT length. The length of the GI can be various values such as 0.4 μs, 0.8 μs, 1.6 μs, 2.4 μs, 3.2 μs.

For convenience of description, although the frequency band used by the first field and the frequency band used by the second field are represented in FIG. 7, they may not exactly coincide with each other. For example, the main band of the first field (L-STF, L-LTF, L-SIG, HE-SIG-A, HE-SIG-B) corresponding to the first frequency band is the second field (HE-STF). , HE-LTF, Data) is the same as the main band, but in each frequency band, the interface may be inconsistent. 4 to 6, since a plurality of null subcarriers, DC tones, guard tones, etc. are inserted in the process of arranging the RU, it may be difficult to accurately match the interface.

The user, that is, the receiving station, may receive the HE-SIG-A 730 and may be instructed to receive the downlink PPDU based on the HE-SIG-A 730. In this case, the STA may perform decoding based on the changed FFT size from the field after the HE-STF 750 and the HE-STF 750. On the contrary, if the STA is not instructed to receive the downlink PPDU based on the HE-SIG-A 730, the STA may stop decoding and configure a network allocation vector (NAV). The cyclic prefix (CP) of the HE-STF 750 may have a larger size than the CP of another field, and during this CP period, the STA may perform decoding on the downlink PPDU by changing the FFT size.

Hereinafter, in the present embodiment, data (or frame) transmitted from the AP to the STA is called downlink data (or downlink frame), and data (or frame) transmitted from the STA to the AP is called uplink data (or uplink frame). Can be expressed in terms. In addition, the transmission from the AP to the STA may be expressed in terms of downlink transmission, and the transmission from the STA to the AP may be expressed in terms of uplink transmission.

In addition, each of the PHY protocol data units (PPDUs), frames, and data transmitted through downlink transmission may be expressed in terms of a downlink PPDU, a downlink frame, and downlink data. The PPDU may be a data unit including a PPDU header and a physical layer service data unit (PSDU) (or MAC protocol data unit (MPDU)). The PPDU header may include a PHY header and a PHY preamble, and the PSDU (or MPDU) may be a data unit including a frame (or an information unit of a MAC layer) or indicating a frame. The PHY header may be referred to as a physical layer convergence protocol (PLCP) header in another term, and the PHY preamble may be expressed as a PLCP preamble in another term.

In addition, each of the PPDUs, frames, and data transmitted through the uplink transmission may be expressed by the term uplink PPDU, uplink frame, and uplink data.

In a WLAN system to which the present embodiment is applied, the entire bandwidth may be used for downlink transmission to one STA and uplink transmission to one STA based on single (or single) -orthogonal frequency division multiplexing (SUDM) transmission. Do. In addition, in the WLAN system to which the present embodiment is applied, the AP may perform downlink (DL) multi-user (MU) transmission based on multiple input multiple output (MU MIMO), and such transmission is referred to as DL MU MIMO transmission. It can be expressed as.

In addition, in the WLAN system according to the present embodiment, an orthogonal frequency division multiple access (OFDMA) based transmission method is preferably supported for uplink transmission and / or downlink transmission. That is, uplink / downlink communication may be performed by allocating data units (eg, RUs) corresponding to different frequency resources to the user. In more detail, in the WLAN system according to the present embodiment, the AP may perform DL MU transmission based on OFDMA, and such transmission may be expressed by the term DL MU OFDMA transmission. When DL MU OFDMA transmission is performed, the AP may transmit downlink data (or downlink frame, downlink PPDU) to each of the plurality of STAs through each of the plurality of frequency resources on the overlapped time resources. The plurality of frequency resources may be a plurality of subbands (or subchannels) or a plurality of resource units (RUs). DL MU OFDMA transmission may be used with DL MU MIMO transmission. For example, DL MU MIMO transmission based on a plurality of space-time streams (or spatial streams) on a specific subband (or subchannel) allocated for DL MU OFDMA transmission is performed. Can be.

In addition, in the WLAN system according to the present embodiment, UL MU transmission (uplink multi-user transmission) may be supported that a plurality of STAs transmit data to the AP on the same time resource. Uplink transmission on the overlapped time resource by each of the plurality of STAs may be performed in a frequency domain or a spatial domain.

When uplink transmission by each of the plurality of STAs is performed in the frequency domain, different frequency resources may be allocated as uplink transmission resources for each of the plurality of STAs based on OFDMA. The different frequency resources may be different subbands (or subchannels) or different resource units (RUs). Each of the plurality of STAs may transmit uplink data to the AP through different frequency resources allocated thereto. Such a transmission method through different frequency resources may be represented by the term UL MU OFDMA transmission method.

When uplink transmission by each of a plurality of STAs is performed on the spatial domain, different space-time streams (or spatial streams) are allocated to each of the plurality of STAs, and each of the plurality of STAs transmits uplink data through different space-time streams. Can transmit to the AP. The transmission method through these different spatial streams may be represented by the term UL MU MIMO transmission method.

The UL MU OFDMA transmission and the UL MU MIMO transmission may be performed together. For example, UL MU MIMO transmission based on a plurality of space-time streams (or spatial streams) may be performed on a specific subband (or subchannel) allocated for UL MU OFDMA transmission.

In a conventional WLAN system that did not support MU OFDMA transmission, a multi-channel allocation method was used to allocate a wider bandwidth (for example, a bandwidth exceeding 20 MHz) to one UE. The multi-channel may include a plurality of 20 MHz channels when one channel unit is 20 MHz. In the multi-channel allocation method, a primary channel rule is used to allocate a wide bandwidth to the terminal. If the primary channel rule is used, there is a constraint for allocating a wide bandwidth to the terminal. Specifically, according to the primary channel rule, when a secondary channel adjacent to the primary channel is used in an overlapped BSS (OBSS) and 'busy', the STA may use the remaining channels except the primary channel. Can't. Accordingly, the STA can transmit the frame only through the primary channel, thereby being limited to the transmission of the frame through the multi-channel. That is, the primary channel rule used for multi-channel allocation in the existing WLAN system may be a big limitation in obtaining high throughput by operating a wide bandwidth in the current WLAN environment where there are not many OBSS.

In the present embodiment to solve this problem is disclosed a WLAN system supporting the OFDMA technology. That is, the above-described OFDMA technique is applicable to at least one of downlink and uplink. In addition, the above-described MU-MIMO technique may be additionally applied to at least one of downlink and uplink. When OFDMA technology is used, a plurality of terminals may be used simultaneously instead of one terminal without using a primary channel rule. Therefore, wide bandwidth operation is possible, and the efficiency of the operation of radio resources can be improved.

As described above, when uplink transmission by each of a plurality of STAs (eg, non-AP STAs) is performed in the frequency domain, the AP has different frequency resources for each of the plurality of STAs based on OFDMA. It may be allocated as a link transmission resource. In addition, as described above, different frequency resources may be different subbands (or subchannels) or different resource units (RUs).

Different frequency resources for each of the plurality of STAs are indicated through a trigger frame.

9 shows an example of a trigger frame. The trigger frame of FIG. 9 allocates resources for uplink multiple-user transmission and may be transmitted from the AP. The trigger frame may consist of a MAC frame and may be included in a PPDU. For example, it may be transmitted through the PPDU shown in FIG. 3, through the legacy PPDU shown in FIG. 2, or through a PPDU specifically designed for the trigger frame. If transmitted through the PPDU of FIG. 3, the trigger frame may be included in the illustrated data field.

Each field shown in FIG. 9 may be partially omitted, and another field may be added. In addition, the length of each field may be varied as shown.

The frame control field 910 of FIG. 9 includes information on the version of the MAC protocol and other additional control information, and the duration field 920 may include time information for NAV configuration or an identifier of the terminal (eg, For example, information about AID may be included.

In addition, the RA field 930 includes address information of a receiving STA of a corresponding trigger frame and may be omitted as necessary. The TA field 940 includes address information of an STA (for example, an AP) that transmits a corresponding trigger frame, and the common information field 950 is common to be applied to a receiving STA that receives the corresponding trigger frame. Contains control information. For example, a field indicating the length of the L-SIG field of the uplink PPDU transmitted in response to the trigger frame, or the SIG-A field of the uplink PPDU transmitted in response to the trigger frame (that is, HE-SIG-A). Information to control the content of the field). In addition, the common control information may include information about the length of the CP of the uplink PPDU transmitted in response to the trigger frame or information about the length of the LTF field.

In addition, it is preferable to include the per user information field (960 # 1 to 960 # N) corresponding to the number of receiving STAs receiving the trigger frame of FIG. The individual user information field may be called a “RU assignment field”.

In addition, the trigger frame of FIG. 9 may include a padding field 970 and a frame check sequence field 980.

Each of the per user information fields 960 # 1 to 960 # N shown in FIG. 9 preferably includes a plurality of subfields.

10 shows an example of a subfield included in a per user information field. Some of the subfields of FIG. 10 may be omitted, and other subfields may be added. In addition, the length of each illustrated subfield may be modified.

The user identifier field 1010 of FIG. 10 indicates an identifier of an STA (ie, a receiving STA) to which per user information corresponds. An example of the identifier may be all or part of an AID. have.

In addition, the RU Allocation field 1020 may be included. That is, when the receiving STA identified by the user identifier field 1010 transmits an uplink PPDU in response to the trigger frame of FIG. 9, the corresponding uplink PPDU through the RU indicated by the RU Allocation field 1020. Send. In this case, the RU indicated by the RU Allocation field 1020 preferably indicates the RU shown in FIGS. 4, 5, and 6. The configuration of the specific RU allocation field 1020 will be described later.

The subfield of FIG. 10 may include a coding type field 1030. The coding type field 1030 may indicate a coding type of an uplink PPDU transmitted in response to the trigger frame of FIG. 9. For example, when BCC coding is applied to the uplink PPDU, the coding type field 1030 is set to '1', and when LDPC coding is applied, the coding type field 1030 is set to '0'. Can be.

Also, the subfield of FIG. 10 may include an MCS field 1040. The MCS field 1040 may indicate an MCS scheme applied to an uplink PPDU transmitted in response to the trigger frame of FIG. 9. For example, when BCC coding is applied to the uplink PPDU, the coding type field 1030 is set to '1', and when LDPC coding is applied, the coding type field 1030 is set to '0'. Can be.

Hereinafter, the present specification proposes an example of improving the control field included in the PPDU. The control field improved by the present specification includes a first control field including control information required for interpreting the PPDU and a second control field including control information for demodulating the data field of the PPDU. do. The first and second control fields may be various fields. For example, the first control field may be the HE-SIG-A 730 illustrated in FIG. 7, and the second control field may be the HE-SIG-B 740 illustrated in FIGS. 7 and 8. Can be.

Hereinafter, a specific example of improving the first or second control field will be described.

In the following example, a control identifier inserted into a first control field or a second control field is proposed. The size of the control identifier may vary, for example, may be implemented with 1-bit information.

The control identifier (eg, 1 bit identifier) may indicate whether 242-RU is allocated, for example when 20 MHz transmission is performed. As shown in FIGS. 4 to 6, RUs of various sizes may be used. These RUs can be broadly divided into two types of RUs. For example, all of the RUs shown in FIGS. 4 to 6 may be classified into 26-type RUs and 242-type RUs. For example, a 26-type RU may include 26-RU, 52-RU, 106-RU, and the 242-type RU may include 242-RU, 484-RU, and larger RUs.

The control identifier (eg, 1 bit identifier) may indicate that 242-type RU has been used. That is, it may indicate that 242-RU is included or 484-RU or 996-RU is included. If the transmission frequency band in which the PPDU is transmitted is a 20 MHz band, 242-RU is a single RU corresponding to the full bandwidth of the transmission frequency band (ie, 20 MHz) band. Accordingly, the control identifier (eg, 1 bit identifier) may indicate whether a single RU corresponding to the full bandwidth of the transmission frequency band is allocated.

For example, if the transmission frequency band is a 40 MHz band, the control identifier (eg, 1 bit identifier) is assigned a single RU corresponding to the entire band (ie, 40 MHz band) of the transmission frequency band. Can be indicated. That is, it may indicate whether the 484-RU has been allocated for the transmission of 40MHz.

For example, if the transmission frequency band is an 80 MHz band, the control identifier (eg, 1-bit identifier) is assigned a single RU corresponding to the entire band of the transmission frequency band (ie, 80 MHz band). Can be indicated. That is, it may indicate whether the 996-RU has been allocated for the transmission of 80MHz.

Various technical effects can be achieved through the control identifier (eg, 1 bit identifier).

First of all, when a single RU corresponding to the entire band of the transmission frequency band is allocated through the control identifier (eg, a 1-bit identifier), it is possible to omit allocation information of the RU. That is, since only one RU is allocated to all bands of the transmission frequency band instead of the plurality of RUs, it is possible to omit allocation information of the RU.

It can also be used as signaling for full-band multi-user full bandwidth MU-MIMO (MIMO). For example, when a single RU is allocated over the full bandwidth of the transmission frequency band, multiple users may be allocated to the single RU. That is, signals for each user are not spatially and spatially distinct, but other techniques (eg, spatial multiplexing) may be used to multiplex the signals for multiple users in the same single RU. Accordingly, the control identifier (eg, 1 bit identifier) may also be used to indicate whether to use the full-band multi-user MIMO as described above.

The block on the left side of FIG. 11 represents information included in the first and / or second control field of the PPDU, and the block on the right side of FIG. 11 represents information included in the data field of the PPDU. The PPDU related to FIG. 11 may be a multi-user, that is, a PPDU for a plurality of receiving devices. In more detail, the structure of the fields of the PPDU may vary for multiple users and a single user, and the example of FIG. 11 may be a PPDU for multiple users.

Although an example of FIG. 11 is shown to be used for 20 MHz transmission, the bandwidth of the transmission frequency band is not limited and may be applied to a 40 MHz, 80 MHz, and 160 MHz transmission.

As indicated in the block on the left of FIG. 11, the above-described control identifier (eg, 1 bit identifier) may be included in the first and / or second control field. For example, when the control identifier 1110 is included in the first control field, information about allocation information 1120 for the RU may be included in the second control field. In addition, the second control field may include identification information 1130 of a receiving device that receives the PPDU of FIG. 11. The identification information 1130 of the receiving device may indicate to which receiving device the data field 1140 corresponding to the second control field is allocated, and may be implemented as, for example, an AID.

As shown in FIG. 11, allocation information for the RU may be omitted in the second control field according to a control identifier (eg, a 1-bit identifier). For example, when the control identifier is set to "1", the allocation information 1120 for the RU may be omitted in the second control field, and the identification information 1130 of the receiving device may be included. In addition, when the control identifier is set to "0", the second control field may include allocation information 1120 for the RU, and may also include identification information 1130 of the receiving device.

The allocation information 1120 for the RU of FIG. 11 may be included in a common field of the SIG-B illustrated in FIG. 8, and the identification information 1130 of FIG. 11 may be included in the SIG-B illustrated in FIG. 8. It may be included in the user-specific field of.

In addition, referring to FIG. 11, the common field of SIG-B may include common information such as RU signaling information and stream allocation related information for the user, and common to all users who receive the PPDU of FIG. 11. May contain information. If the above-mentioned allocation information 1120 for the RU is omitted, there is a technical effect that the overhead is reduced.

According to another example, when 20 MHz transmission is used, the above-described control identifier (eg, 1 bit identifier) may be omitted since 242-RU is allocated as a single user (SU) transmission. . In this case, the operation may vary according to the first control field (eg, HE-SIG-A) SU / MU identification field. That is, when the SU / MU identification field included in the first control field indicates MU transmission, the control identifier is omitted and only an example of assigning 26-type RUs may be possible.

Hereinafter, another example of the present embodiment will be described.

12 shows an example of this embodiment for a 40 MHz transmission.

The left block of FIG. 12 indicates information corresponding to the first and / or second control field. For convenience of description, the left block of FIG. 12 corresponds to the second control field (ie, SIG-B), and the right block of FIG. 12 corresponds to the data field of the PPDU.

As shown, each control field and data field correspond to a 20 MHz band.

In the example of FIG. 12, if the above-described control identifier (eg, 1-bit identifier) is set to “1”, allocation information for the RU may be omitted. In the example of FIG. 12, a control identifier (eg, 1 bit identifier) may indicate whether 242-RU (or 242-type RU) is used.

Referring to FIG. 12, the control identifier is included in the front of the common field of the SIG-B. In the example of FIG. 12, the control identifier may be called “242 unit bitmap”. The RU allocation information may be omitted according to the "242 unit bitmap" as in FIG. 11, and the effect of reducing overhead is also the same.

If only 242-RU is allocated on the full 40MHz channel, the “242 unit bitmap” can be set to “1”. Referring to FIG. 12B, if only 26-type RU is allocated in the 40MHz channel, the “242 unit bitmap” may be set to “00”. Referring to the sub-figure (c) of FIG. 12, when only 242-RU is allocated in all 40 MHz channels, the “242 unit bitmap” may be set to “11”. Since the last symbol of the SIG-B part must be aligned with the longest SIGB symbol of the 20 MHz channels, omitting RU allocation information in only one 20 MHz channel is less effective in reducing overhead. Accordingly, an example in which “242 unit bitmap” is set to “1” is possible when only 242-RU is allocated in all 20 MHz channels.

In the following example, another example of the above-described control identifier (eg, 1-bit identifier) is proposed. Specifically, an example of dividing the above-described control identifier into two identifiers is proposed. That is, a first identifier indicating whether a 242-type RU is allocated to each 20MHz channel and a second identifier indicating whether a 484-RU (or another sized 242-type RU) is allocated to the corresponding 20MHz channel are proposed. .

We also propose an improved example of the frequency mapping relationship between the second control field (ie, SIG-B) and the data field. An additional example of frequency mapping between the second control field (ie, SIG-B) and the data field is applicable to the above-described example (ie, the example of FIG. 11 or FIG. 12), but for convenience of description, FIG. 13. A description will be given based on an example.

In the example of FIG. 13, a first identifier 1310 is configured per 20 MHz channel. That is, four 1-bit identifiers indicating whether a 242-type RU is allocated to each 20MHz channel may be inserted. In this case, since the 484-RU may be allocated within the 80 MHz band, an additional identifier indicating whether a specific 20 MHz channel (ie, 242 chunk) is used for 242-RU or 484-RU, that is, the aforementioned The second identifier 1320 may be further included. When both the first and second identifiers are used, a total of 8 bits of information may be used for the first / second identifiers in the 80 MHz band.

The first and second identifiers may also be indicated as “242 unit bitmap” and “484 unit assignment indication field”. The first and second identifiers may be implemented as fields of two bits. For example, if the second identifier 1350 corresponding to the first channel and the second identifier 1360 corresponding to the second channel are set to “00”, this is not assigned 484-RU in the corresponding PPDU. For example, if the first and second identifiers are set to "1" and "0", it may be indicated that only 242-RU is allocated.

An example of FIG. 13 is an example of the first identifier 1310 and the second identifier 1320 as shown. However, an example regarding a frequency mapping relationship between the second control field (ie, SIG-B) and the data field may be applied.

Specifically, the second control field (ie, SIG-B) may be configured separately for each 20MHz channel. However, the present specification proposes an example of independently configuring the lower two 20 MHz channels 1330 and the upper two 20 MHz channels 1340. Specifically, an example of configuring the SIG-B corresponding to the upper or lower two 20 MHz channels, replicating the same, and using the same for the remaining two 20 MHz channels is proposed.

All or part of the fields proposed in the present specification, for example, SIG-B, is preferably configured according to the above-described replication method. For example, when four 20 MHz channels shown in the example of FIG. 13 are divided into first to fourth channels in order from the bottom, SIG-B included in the first and second channels is the third and fourth channels. SIG-B included in the and the contents (contents) may be the same. In addition, as shown, SIG-B corresponding to the second channel first displays AID3 corresponding to STA3, and then displays AID corresponding to STA4. Accordingly, the SIG-B corresponding to the second channel may allocate STA3 to a data field corresponding to the second channel and STA4 to a data field corresponding to the fourth channel. That is, the SIG-B corresponding to the second channel may first indicate STA identification information regarding the data field corresponding to the second channel, and then indicate STA identification information regarding the data field corresponding to the fourth channel. have.

In addition, referring to FIG. 13, the SIG-B corresponding to the first channel indicates a data field corresponding to the first channel, and indicates an STA (ie, STA 1) assigned to the data field corresponding to the first channel. And may indicate a data field corresponding to the third channel, and indicate an STA (ie, STA 2) allocated to the data field corresponding to the third channel. That is, the SIG-B included in the first channel may indicate STA identification information regarding the data field corresponding to the first channel and STA identification information regarding the data field corresponding to the third channel.

14 shows another example according to the present specification.

Referring to FIG. 14, a first identifier 1410 is included at the beginning of a SIG-B field corresponding to each 20 MHz, followed by a second identifier 1420.

The first / second identifier of FIG. 14 may be used in the same manner as the first / second identifier of FIG. 13. In addition, the example of FIG. 14 may have a predetermined mapping relationship between the SIG-B and the data field, similarly to the example of FIG. 13. However, unlike the example of FIG. 13, in the example of FIG. 14, the SIG-B corresponding to the first channel is mapped to the data field corresponding to the first / second channel, and the SIG-B corresponding to the second channel is added. Mapped to the data field corresponding to the third / fourth channel.

15 shows another example according to the present specification.

Referring to FIG. 15, a first identifier 1510 is included at the beginning of a SIG-B field corresponding to each 20 MHz, followed by a second identifier 1520. The first / second identifier according to the example of FIG. 15 may correspond to the first / second identifier of FIGS. 13 and / or 14.

As shown in FIG. 15, all or part of information of the SIG-B field corresponding to the first / second channel may be duplicated to the third / fourth channel. That is, as shown in FIG. 15, the SIG-B field corresponding to the first / second channel indicates {AID1, 2} and {AID1, 3}, and the SIG-B corresponding to the third / fourth channel. The field may also indicate {AID1, 2} and {AID1, 3}.

Referring to FIG. 15, the second identifier 1550 corresponding to the first channel indicates "1", and the second identifier 1560 corresponding to the second channel indicates "0". This indicates that 484-RU is allocated for the first / second channel and 484-RU is not allocated for the third / fourth channel. In the example of FIG. 15, the first identifier 1510 is all set to 1, so that the data field of FIG. 15 is allocated 484-RU for the first / second channel, 242-RU for the third channel, 242-RU is also allocated for the fourth channel.

Other features of the example of FIG. 15 are the same as those of FIGS. 13 to 14.

16 shows another example according to the present specification.

Referring to FIG. 16, a first identifier 1610 is included at the beginning of a SIG-B field corresponding to each 20 MHz, followed by a second identifier 1620.

As shown in FIG. 16, all or part of information of the SIG-B field corresponding to the first / second channel may be duplicated to the third / fourth channel. That is, as shown in FIG. 16, the SIG-B field corresponding to the first / second channel indicates {AID1, 2} and {AID3, 2}, and the SIG-B corresponding to the third / fourth channel. The field may also indicate {AID1, 2} and {AID3, 2}.

Referring to FIG. 16, the second identifier 1650 corresponding to the first channel indicates “0”, and the second identifier 1660 corresponding to the second channel indicates “1”. This indicates that no 484-RU is allocated for the first / second channel and 484-RU is allocated for the third / fourth channel. In the example of FIG. 16, the first identifier 1610 is all set to 1, so that the data fields of FIG. 16 are allotted 242-RU for the first / second channel and 484- for the third / 4 channel. RU is allocated.

Other features of the example of FIG. 16 are the same as those of FIGS. 13 to 15.

17 shows another example according to the present specification.

Referring to FIG. 17, a first identifier 1710 is included in front of a SIG-B field corresponding to each 20 MHz, followed by a second identifier 1720.

As illustrated in FIG. 17, all or part of information of the SIG-B field corresponding to the first / second channel may be duplicated to the third / fourth channel. That is, as shown in FIG. 17, the SIG-B field corresponding to the first / second channel indicates {AID1} and {AID2}, and the SIG-B field corresponding to the third / fourth channel is also {AID1. } And {AID2}.

Referring to FIG. 17, the second identifier 1750 corresponding to the first channel indicates “1”, and the second identifier 1760 corresponding to the second channel indicates “1”. This indicates that 484-RU is allocated for the first / second channel and also 484-RU is allocated for the third / fourth channel.

Other features of the example of FIG. 17 are the same as those of FIGS. 13 to 16.

18 shows another example according to the present specification.

Referring to FIG. 18, a first identifier 1810 is included at the beginning of a SIG-B field corresponding to each 20 MHz, followed by a second identifier 1820.

As shown in FIG. 18, all or part of information of the SIG-B field corresponding to the first / second channel may be duplicated to the third / fourth channel. That is, as shown in FIG. 18, the SIG-B field corresponding to the first / second channel indicates {AID1, 2} and {AID1, 2}, and the SIG-B corresponding to the third / fourth channel. The field may also indicate {AID1, 2} and {AID1, 2}.

Referring to FIG. 18, the second identifier 1850 corresponding to the first channel indicates “1”, and the second identifier 1860 corresponding to the second channel indicates “1”. This indicates that 484-RU is allocated for the first / second channel and also 484-RU is allocated for the third / fourth channel.

Other features of the example of FIG. 18 are the same as those of FIGS. 13 to 17.

Fig. 19 is a diagram showing a relationship between SIG-A, SIG-B and data fields according to the present embodiment. The example of FIG. 19 shows the above-mentioned content on one PPDU.

The PPDU 1901 of FIG. 19 may include all or part of the field illustrated in FIG. 7. In detail, as illustrated, the first control field 1910, the

second control field

1920 and 1930, and the data field 1940 may be included. The first control field 1910 may correspond to the aforementioned SIG-A or HE-SIG A, and the second control field 1920 may correspond to the aforementioned SIG-B or HE-SIG B.

The first control field 1910 may include the HE-SIG A 730 of FIG. 7 and the technical features illustrated in FIGS. 11 to 18. In detail, the first control field 1910 may include control information for interpretation of the PPDU 1901. For example, as described in the example of FIG. 7, the PPDU 1901 may include a subfield indicating the transmission frequency band to which the PPDU 1901 is transmitted (indicative of 20 MHz, 40 MHz, 80 MHz, 160 MHz, and the like).

In addition, the control identifier (eg, the first identifier and / or the second identifier) described with reference to FIGS. 11 to 18 may be included. In detail, the first control field 1910 may include a 1-bit identifier indicating whether a single RU corresponding to the full bandwidth of the transmission frequency band is allocated. When the control identifier (eg, 1-bit identifier) of the first control field 1910 is set to “1”, a single RU corresponding to the full bandwidth of the transmission frequency band is allocated. Is indicated. That is, when the transmission frequency band is a 20 MHz band, a single 242-RU is allocated, for example, when the transmission frequency band is an 80 MHz band, a single 996-RU is indicated. On the other hand, as described above, the 1-bit identifier has a technical effect that can be signaled for full-band multi-user full-width MU-MIMO (MIMO).

When the example of FIG. 19 is applied to an 80 MHz transmission, the first control field 1910 may be generated in a 20 MHz unit and then included in the PPDU 1901 in a form duplicated according to a transmission frequency band. That is, the first control field 1910 may be generated in units of 20 MHz and duplicated to fit the 80 MHz band.

The second control field may correspond to the HE-SIG B field including the common field and the user-specific field shown in FIG. 8. That is, the second control field may include the common field 1920 and the user-specific field 1930. As described above, the common field 1920 of the SIG-B may include common information such as RU allocation information for the user. For example, RU allocation information in the form of a lookup-table including specific n-bit mapping information may be included. The RU allocation information may indicate allocation or allocation information of the RU applied to the corresponding data field 1940. That is, as shown in Figures 4 to 6 may indicate a structure in which a plurality of RU is arranged. All STAs that have received the common field 1920 of the second control field may confirm to which RU the corresponding data field 1940 is configured.

In summary, the second control field generally includes allocation information for a resource unit (RU) through the common field 1920. However, if the control identifier (eg, 1 bit identifier) included in the first control field 1910 is set to "1", allocation information for the RU is preferably omitted. That is, the common field 1920 may be omitted. If the control identifier is set to "1", since only one RU is used, the common field 1920 can be omitted because it is not necessary to configure allocation information for the RU separately. In other words, when the control identifier (eg, 1-bit identifier) included in the first control field 1910 is set to “0”, the common field 1920 of the second control field is used for a resource unit (RU). If the control identifier (eg, 1-bit identifier) included in the first control field 1910 is set to “1”, the common field 1920 of the second control field includes a resource unit. May not include allocation information for

The

second control fields

1920 and 1930 are used for demodulation of the data field 1940. In this case, the second control field and the data field 1940 may have a mapping relationship as shown in FIGS. 13 to 18.

For example, when the example of FIG. 19 relates to 80 MHz transmission, the second control field may correspond to the first to fourth SIG-B channels. That is, it may be divided into four 20 MHz channels.

In this case, the contents of the

second control fields

1921 and 1931 corresponding to the first SIG-B channel may be the same as the contents of the

second control fields

1923 and 1933 corresponding to the third SIG-B channel. Can be. In other words, part of the second control field may be duplicated in the PPDU 1901. Replication for the second control field may be variously implemented.

For convenience of description, four second control fields corresponding to the first to fourth SIG-B channels may be referred to as first, second, third, and fourth signal fields. In this case, the

second signal fields

1922 and 1932 may be duplicated to configure the

fourth signal fields

1924 and 1934. That is, the contents of the

second control fields

1922 and 1932 corresponding to the second SIG-B channel may be the same as the contents of the

second control fields

1924 and 1934 corresponding to the fourth SIG-B channel. have.

When such duplication is performed, the

first signal fields

1921 and 1931 may correspond to the data field 1941 of the first data channel and the data field 1943 of the third data channel. In addition, the

second signal fields

1922 and 1932 may correspond to the data field 1942 of the second data channel and the data field 1944 of the fourth data channel.

In other words, the common field 1921 included in the

first signal fields

1921 and 1931 may include allocation information about the RU applied to the data field 1941 of the first data channel and the data field 1943 of the third data channel. ) May indicate allocation information about the RU to be applied. In this case, in the

first signal fields

1921 and 1931, allocation information about the RU applied to the data field 1194 of the first data channel is first inserted in the form of one BCC block, and then the third data. One BCC block for the data field 1943 of the channel is inserted.

In addition, the user specific field 1931 included in the

first signal fields

1921 and 1931 may include identification information (for example, AID) and a third data channel of the STA allocated to the data field 1941 of the first data channel. May include identification information (eg, AID) of the STA allocated to the data field 1943 of the STA. In this case, the two BCC blocks described above are inserted into the

first signal fields

1921 and 1931, and then the BCC blocks for the STAs allocated to the data fields 1941 of the first data channel are inserted. The BCC block for the STA allocated to the data field 1943 of the third data channel is inserted.

In FIG. 19, the frequency bands through which the

second control fields

1920 and 1930 are transmitted are represented by four “SIG-B channels”, and the frequency bands through which the data field 1940 is transmitted are represented by four “data channels”. However, it can be understood that each SIG-B channel and data channel correspond to the four frequency bands described with reference to FIG. 7. That is, as described in the example of FIG. 7, each interface of the data channel and each interface of the SIG-B channel may not coincide completely. However, when the reference is made based on the corresponding 20 MHz frequency band, The

second control fields

1921 and 1931 correspond to two

data fields

1941 and 1943 corresponding to the first and third frequency bands. In addition, the

second control fields

1922 and 1932 corresponding to the second frequency band correspond to two

data fields

1942 and 1944 corresponding to the second / fourth frequency band.

20 is a diagram illustrating an example of SIG-B used for 80 MHz transmission.

The example of FIG. 20 proposes the example which further refined the example of FIG. As shown in FIG. 20, SIG-B includes a common field 2010 and a user specific field 2020. In addition, the common field 2010 and the user specific field 2020 of the SIG-B include four fields corresponding to four

frequency bands

2041, 2042, 2043, and 2044 corresponding to 20 MHz channels, respectively. In FIG. 20, the four SIG-B fields may be called various names such as first to fourth signal fields.

When divided into 20 MHz band units as shown in FIG. 20, the SIG-B corresponding to the first frequency band 2041 is mapped to data fields of the first and third frequency bands and corresponds to the second frequency band 2042. SIG-B is preferably mapped to the data field of the second and fourth frequency band. In addition, the SIG-B corresponding to the first frequency band 2041 may be duplicated so that the SIG-B corresponding to the third frequency band 2043 may be configured, and the SIG-B corresponding to the second frequency band 2042. May be duplicated to configure SIG-B corresponding to the fourth frequency band 2044.

Referring to FIG. 20, the common field corresponding to the first frequency band 2041 includes an RU signaling field, which is used for data fields corresponding to the first and third frequency bands. Each RU signaling field shown in FIG. 20 may be configured with one look-up table based on 20 MHz. Since the common field corresponding to the first frequency band 2041 corresponds to a data field corresponding to two frequency bands, two RU signaling fields may be transmitted at the same time. The first of the two RU signaling fields indicates a data field corresponding to the first frequency band 2041, the second field indicates a data field corresponding to the third frequency band 2043,

The same technical feature applies to SIG-B corresponding to the second frequency band 2042. That is, SIG-B corresponding to the second frequency band 2042 may include two RU signaling fields for data fields corresponding to the second and

fourth frequency bands

2042 and 2044.

Two RU signaling fields do not exist independently of each other, and may correspond to one unified look-up table. That is, it may be designed to indicate a discontinuous 40MHz allocation.

As described above, the SIG-B corresponding to the first and third frequency bands is preferably replicated on the second and fourth frequency bands.

The above-described example may be variously modified. For example, the additional technical features described below may be applied to the RU lookup table and the RU signaling field.

For example, the RUs corresponding to the band of 20 MHz may be configured with a combination of 26-RU, 52-RU, 106-RU (or 242-RU, aggregated 484-RU, 996-RU). In this case, when the number of combinations is 32 or less, the RU lookup table may be configured through 5-bit information. In this case, if the MU-MIMO scheme is set to be used only for 106-RU or more RUs, there are about 12 cases of 106-RU allocations. That is, when additionally using a 3-bit or 4-bit MU-MIMO indicator (i.e., MU-MIMO field), 1) information on the combination of RUs for 20 MHz and 2) information on the RU to which MU-MIMO applies You can even signal.

In this case, the signal related to the MU-MIMO technique can be embodied as follows.

For example, when 106-RU is included in a combination of RUs indicated by 5-bit information, a 3-bit or 4-bit MU-MIMO indicator (ie, MU-MIMO field) may be specified as follows.

1) 3-bit MU-MIMO indicator: can indicate a total of 8 user STA that can be multiplexed to the 106-RU. For example, it is possible to indicate the total number of users. Specifically, in case of “000”, one user and “111” may indicate that a total of eight user STAs are multiplexed according to the MU-MIMO scheme to the corresponding 106-RU. That is, the MU-MIMO scheme may be applied and the number of user STAs multiplexed according to the MU-MIMO scheme may be indicated simultaneously.

For example, if two 106-RUs are included in a combination of RUs indicated by 5-bit information, the MU-MIMO indicator (ie, MU-MIMO field) may be specified as follows.

2) 4-bit MU-MIMO indicator

First, a user STA multiplexed on each 106-RU by 2 bits may be indicated. In this case, a combination of the number of users that can be multiplexed into each 106-RU may be limited.

a) Two bits for the first 106-RU may indicate four user STAs, and two bits for the second 106-RU may indicate four user STAs.

b) The number of 16 cases represented by 4-bit information can be used to indicate the combination of user STAs that can be assigned to each 106-RU.

-E.g. (2,6), (4,4), (8,8),...

The number of 16 cases represented by 3-bit information can be used to indicate the combination of user STAs that can be assigned to each 106-RU.

-E.g. (2,6), (4,4), (8,8)...

The PPDU used in the IEEE standard is mainly described as a PPDU structure transmitted on 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.

Wireless networks are ubiquitous, usually indoors and often installed outdoors. Wireless networks use various techniques to send and receive information. For example, but not limited to, two widely used technologies for communication are those that comply with IEEE 802.11 standards such as the IEEE 802.11n standard and the IEEE 802.11ac standard.

The IEEE 802.11 standard specifies a common Medium Access Control (MAC) layer that provides a variety of features to support the operation of IEEE 802.11-based wireless LANs (WLANs). The MAC layer utilizes protocols that coordinate access to shared radios and improve communications over wireless media, such as IEEE 802.11 stations (such as a PC's wireless network card (NIC) or other wireless device or station (STA) and access point ( Manage and maintain communication between APs).

IEEE 802.11ax is the successor to 802.11ac and has been proposed to improve the efficiency of WLAN networks, especially in high density areas such as public hotspots and other high density traffic areas. IEEE 802.11 can also use Orthogonal Frequency Division Multiple Access (OFDMA). The High Efficiency WLAN Research Group (HEW SG) within the IEEE 802.11 Work Group is dedicated to improving system throughput / area in high-density scenarios of APs (access points) and / or STAs (stations) in relation to the IEEE 802.11 standard. We are considering improving efficiency.

Wearable devices and small computing devices such as sensors and mobile devices are constrained by small battery capacities, but use wireless communication technologies such as Wi-Fi, Bluetooth®, and Bluetooth® Low Energy (BLE). Support, connect to and exchange data with other computing devices such as smartphones, tablets, and computers. Since these communications consume power, it is important to minimize the energy consumption of such communications in these devices. One ideal strategy to minimize energy consumption is to power off the communication block as frequently as possible while maintaining data transmission and reception without increasing delay too much. That is, the communication block is transmitted immediately before the data reception, and only when there is data to wake up, the communication block is turned on and the communication block is turned off for the remaining time.

Hereinafter, a low-power wake-up receiver (LP-WUR) will be described.

The communication system (or communication subsystem) described herein includes a main radio (802.11) and a low power wake up receiver.

The main radio is used for transmitting and receiving user data. The main radio is turned off if there are no data or packets to transmit. The low power wake-up receiver wakes up the main radio when there is a packet to receive. At this time, the user data is transmitted and received by the main radio.

The low power wake-up receiver is not for user data. It is simply a receiver to wake up the main radio. In other words, the transmitter is not included. The low power wake-up receiver is active while the main radio is off. Low power wake-up receivers target a target power consumption of less than 1 mW in an active state. In addition, low power wake-up receivers use a narrow bandwidth of less than 5 MHz. In addition, the target transmission range of the low power wake-up receiver is the same as that of the existing 802.11.

21 illustrates a low power wake-up receiver in an environment in which data is not received. 22 illustrates a low power wake-up receiver in an environment in which data is received.

As shown in Figs. 21 and 22, if there is data to be transmitted and received, one method of implementing an ideal transmission and reception strategy is a main radio such as Wi-Fi, Bluetooth® radio, or Bluetooth® radio (BLE). Adding a low power wake-up receiver (LP-WUR) that can wake up.

Referring to FIG. 21, the Wi-Fi / BT / BLE 2120 is turned off and the low power wake-up receiver 2130 is turned on without receiving data. Some studies show that the low power wake-up receiver (LP-WUR) can consume less than 1mW.

However, as shown in FIG. 22, when a wakeup packet is received, the low power wakeup receiver 2230 may receive the entire Wi-Fi / BT / BLE radio 2220 so that the data packet following the wakeup packet can be correctly received. Wake up). In some cases, however, actual data or IEEE 802.11 MAC frames may be included in the wakeup packet. In this case, it is not necessary to wake up the entire Wi-Fi / BT / BLE radio (2220), but only a part of the Wi-Fi / BT / BLE radio (2220) to perform the necessary process. This can result in significant power savings.

One example technique disclosed herein defines a method for a granular wakeup mode for Wi-Fi / BT / BLE using a low power wakeup receiver. For example, the actual data contained in the wakeup packet can be passed directly to the device's memory block without waking up the Wi-Fi / BT / BLE radio.

As another example, if a wakeup packet contains an IEEE 802.11 MAC frame, only the MAC processor of the Wi-Fi / BT / BLE wireless device needs to wake up to process the IEEE 802.11 MAC frame included in the wakeup. That is, the PHY module of the Wi-Fi / BT / BLE radio can be turned off or kept in a low power mode.

A number of granular wakeup modes have been defined for Wi-Fi / BT / BLE radios that use low power wake-up receivers, requiring that the Wi-Fi / BT / BLE radio be powered on when a wake-up packet is received. However, according to the above embodiment, only necessary parts (or components) of the Wi-Fi / BT / BLE radio can be selectively woken up, thereby saving energy and reducing the waiting time. Many solutions that use low-power wake-up receivers to receive wake-up packets wake up the entire Wi-Fi / BT / BLE radio. One exemplary aspect discussed herein wakes up only the necessary portions of the Wi-Fi / BT / BLE radio required to process the received data, saving significant amounts of energy and reducing unnecessary latency in waking up the main radio. Can be.

In addition, in the above embodiment, the low power wake-up receiver 2230 may wake up the main radio 2220 based on the wake-up packet transmitted from the transmitter 2200.

In addition, the transmitter 2200 may be set to transmit a wakeup packet to the receiver 2210. For example, the low power wake-up receiver 2230 may be instructed to wake up the main radio 2220.

The wakeup packet may include one or more legacy preambles. One or more legacy devices may decode or process the legacy preamble.

In addition, the wakeup packet may include a payload after the legacy preamble. The payload may be modulated by a simple modulation scheme, for example, an On-Off Keying (OOK) modulation scheme.

Referring to FIG. 23, the transmitter may be configured to generate and / or transmit a wakeup packet 2300. The receiving device may be configured to process the received wake-up packet 2300.

In addition, the wakeup packet 2300 may include a legacy preamble or any other preamble 2310 defined by the IEEE 802.11 specification. In addition, the wakeup packet 2300 may include a payload 2320.

Legacy preambles provide coexistence with legacy STAs. The legacy preamble 2310 for coexistence uses the L-SIG field to protect the packet. The 802.11 STA may detect the start of a packet through the L-STF field in the legacy preamble 2310. The 802.11 STA can know the end of the packet through the L-SIG field in the legacy preamble 2310. In addition, by adding a BPSK modulated symbol after the L-SIG, a false alarm of an 802.11n terminal can be reduced. One symbol (4us) modulated with BPSK also has a 20MHz bandwidth like the legacy part. The legacy preamble 2310 is a field for third party legacy STAs (STAs not including LP-WUR). The legacy preamble 2310 is not decoded from the LP-WUR.

Payload 2320 may include wake-up preamble 2322. Wake-up preamble 2322 may include a sequence of bits configured to identify wake-up packet 2300. The wakeup preamble 2232 may include, for example, a PN sequence.

In addition, the payload 2320 may include a MAC header 2324 including address information of the receiving apparatus that receives the wakeup packet 2300 or an identifier of the receiving apparatus.

In addition, the payload 2320 may include a frame body 2326 that may include other information of the wakeup packet. For example, the frame body 2326 may include length or size information of the payload.

In addition, the payload 2320 may include a Frame Check Sequence (FCS) field 2328 including a Cyclic Redundancy Check (CRC) value. For example, it may include a CRC-8 value or a CRC-16 value of the MAC header 2324 and the frame body 2326.

Referring to FIG. 24, the wakeup packet 2400 includes a legacy preamble 802.11 preamble 2410 and a payload modulated by OOK. That is, the legacy preamble and the new LP-WUR signal waveform coexist.

In addition, the legacy preamble 2410 may be modulated according to the OFDM modulation scheme. That is, the OOK scheme is not applied to the legacy preamble 2410. In contrast, the payload may be modulated according to the OOK method. However, the wakeup preamble 2422 in the payload may be modulated according to another modulation scheme.

If legacy preamble 2410 is transmitted on a channel bandwidth of 20 MHz to which 64 FFT is applied, the payload may be transmitted on a channel bandwidth of about 4.06 MHz. This will be described later in the OOK pulse design method.

First, a modulation scheme using the OOK scheme and a Manchester coding scheme will be described.

Referring to FIG. 25, information in the form of a binary sequence having 1 or 0 as a bit value is represented. By using a bit value of 1 or 0 of the binary sequence information, OOK modulation can be performed. That is, in consideration of the bit values of the binary sequence information, it is possible to perform the communication of the OOK modulation method. For example, when the light emitting diode is used for visible light communication, the light emitting diode is turned on when the bit value constituting the binary sequence information is 1, and the light emitting diode is turned off when the bit value is 0. The light emitting diode can be made to blink. 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. 25, information of a binary sequence form having 10 bit values is used. Referring to FIG. 25, there is information in the form of a binary sequence having a value of '1001101011'. As described above, when the bit value is 1, the transmitter is turned on, and when the bit value is 0, the transmitter is turned off, the symbol is turned on at 6 bit values out of 10 bit values. ) do. Therefore, when the symbol is turned on in all 10 bit values, if the power consumption is 100%, the power consumption is 60% according to the duty cycle of FIG. 8.

That is, it can be said that the power consumption of the transmitter is determined according to the ratio of 1 and 0 constituting the binary sequence information. In other words, if there is a constraint that the power consumption of the transmitter must be kept at a certain value, the ratio of 1 and 0, which constitutes information in binary sequence form, must also be maintained. For example, in the case of lighting equipment, since the lighting must be maintained at a specific luminance value desired by people, the ratio of 1 and 0 constituting the information in the form of a binary sequence must also be maintained.

However, since the receiver is mainly a wake-up receiver (WUR), the transmission power is not important. The main reason for using OOK is that the power consumption is very low when decoding the received signal. Until the decoding is performed, there is no significant difference in power consumption in the main radio or WUR, but a large difference occurs in the decoding process. 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 (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.

26 shows a method of designing a OOK pulse according to the present embodiment.

The OFDM transmitter of 802.11 can be reused to generate OOK pulses. The transmitter can generate a sequence having 64 bits by applying a 64-point IFFT as in 802.11.

The transmitter should generate the payload of the wakeup packet by modulating the OOK method. However, since the wakeup packet is for low power communication, the OOK method is applied to the ON-signal. The on signal is a signal having an actual power value, and the off signal (OFF-signal) corresponds to a signal having no actual power value. The off signal is also applied to the OOK method, but the signal is not generated using the transmitter, and since no signal is actually transmitted, it is not considered in the configuration of the wakeup packet.

In the OOK method, information (bit) 1 may be an on signal and information (bit) 0 may be an off signal. Alternatively, when the Manchester coding scheme is applied, information 1 may indicate a transition from an off signal to an on signal, and information 0 may indicate a transition from an on signal to an off signal. Alternatively, on the contrary, the information 1 may indicate the transition from the on signal to the off signal, and the information 0 may indicate the transition from the off signal to the on signal. Manchester coding scheme will be described later.

Referring to FIG. 26, as shown in the right frequency domain graph 2620, a transmitter applies a sequence by selecting 13 consecutive subcarriers of a 20 MHz band as a reference band as a sample. In FIG. 26, 13 subcarriers located among the subcarriers in the 20 MHz band are selected as samples. That is, a subcarrier whose subcarrier index is from -6 to +6 is selected from the 64 subcarriers. In this case, the subcarrier index 0 may be nulled to 0 as the DC subcarrier. Set a specific sequence only to the 13 subcarriers selected as samples, and set all subcarriers except the subcarriers (subcarrier indexes -32 to -7 and subcarrier indexes +7 to +31) to 0. .

In addition, since subcarrier spacing is 312.5 KHz, 13 subcarriers have a channel bandwidth of about 4.06 MHz. That is, it can be said that power is provided only for 4.06MHz in the 20MHz band in the frequency domain. By moving the power to the center, the signal to noise ratio (SNR) can be increased and the power consumption of the AC / DC converter of the receiver can be reduced. In addition, the power consumption can be reduced by reducing the sampling frequency band to 4.06MHz.

In addition, as shown in the left time domain graph 2610 of FIG. 26, the transmitter may generate one on-signal in the time domain by performing a 64-point IFFT on 13 subcarriers. One on-signal has a size of 1 bit. That is, a sequence composed of 13 subcarriers may correspond to 1 bit. On the other hand, the transmitter may not transmit the off signal at all. When performing IFFT, a 3.2us symbol may be generated, and if a CP (Cyclic Prefix, 0.8us) is included, one symbol having a length of 4us may be generated. That is, one bit indicating one on-signal may be loaded in one symbol.

The reason for configuring and sending the bits as in the above-described embodiment is to reduce power consumption by using an envelope detector in the receiver. As a result, the receiving device can decode the packet with the minimum power.

However, the basic data rate for one information may be 125 Kbps (8us) or 62.5Kbps (16us).

Generalizing the above, the signal transmitted in the frequency domain is as follows. That is, each signal having a length of K in the 20 MHz band may be transmitted on K consecutive subcarriers of a total of 64 subcarriers. That is, K may correspond to the bandwidth of the OOK pulse by the number of subcarriers used to transmit a signal. All other coefficients of the K subcarriers are zero. In this case, the indices of the K subcarriers used by the signal corresponding to the information 0 and the information 1 are the same. For example, the subcarrier index used may be represented 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).

Manchester coding is a type of line coding, and may indicate information as shown in the following table in a manner in which a transition of a magnitude value occurs in the middle of one bit period.

That is, Manchester coding means a method of converting data from 1 to 01, 0 to 10, 1 to 10, and 0 to 01. Table 1 shows an example in which data is converted from 1 to 10 and 0 to 01 using Manchester coding.

As shown in Fig. 27, the bit string to be transmitted, the Manchester coded signal, the clock reproduced on the receiving side, and the data reproduced on the clock are shown in order from top to bottom.

When the transmitting side transmits data using the Manchester coding scheme, the receiving side reads the data a little later on the basis of the transition point transitioning from 1 → 0 or 0 → 1 and recovers the data, and then transitions to 1 → 0 or 0 → 1 The clock is recovered by recognizing the transition point as the clock transition point. Alternatively, when the symbol is divided based on the transition point, it can be simply decoded by comparing the power at the front and the back at the center of the symbol.

As shown in FIG. 27, the bit string to be transmitted is 10011101, the Manchester coded signal is 0110100101011001, and the clock reproduced on the receiving side recognizes the transition point of the Manchester coded signal as the transition point of the clock. Then, the data is recovered by using the reproduced clock.

By using the Manchester coding scheme, it is possible to communicate in a synchronous manner using only a data transmission channel without using a separate clock.

In addition, this method can use the TXD pin for data transmission and the RXD pin for reception by using only the data transmission channel. Therefore, synchronized bidirectional transmission is possible.

This specification proposes various symbol types that can be used in the WUR and thus data rates.

Since STAs requiring robust performance and STAs receiving strong signals from APs are mixed, it is necessary to support efficient data rates in some situations. In order to obtain reliable and robust performance, a symbol coding based symbol coding technique and a symbol repetition technique may be used. In addition, a symbol reduction technique may be used to obtain a high data rate.

In this case, each symbol may be generated using an existing 802.11 OFDM transmitter. In addition, the number of subcarriers used to generate each symbol may be thirteen. However, it is not limited thereto.

In addition, each symbol may use OOK modulation formed of an ON-signal and an OFF-signal.

One symbol generated for the WUR may be composed of a CP (Cyclic Prefix or Guard Interval) and a signal part representing actual information. Symbols having various data rates may be designed by variously setting or repeating the lengths of the CP and the actual information signal.

The following are various examples of symbol types.

For example, the basic WUR symbol may be represented as CP + 3.2us. That is, one bit is represented using a symbol having the same length as the existing Wi-Fi. Specifically, the transmitting apparatus applies a specific sequence to all available subcarriers (for example, 13 subcarriers) and then performs IFFT to form an information signal portion of 3.2 us. In this case, a coefficient of 0 may be loaded on the DC subcarrier or the middle subcarrier index among all available subcarriers.

Different sequences may be applied to the available subcarriers according to the 3.2us on signal and the 3.2us off signal. A 3.2us off signal can be generated by applying all coefficients to zero.

CP may be used by adopting a specific length from the rear of the information signal 3.2us immediately behind. At this time, CP may be 0.4us or 0.8us. This length is equal to the guard interval of 802.11ac.

Accordingly, one bit information corresponding to one basic WUR symbol may be represented as shown in the following table.

Information ‘0’Information ‘0’	Information ‘1’Information ‘1’
3.2us OFF-signal3.2us OFF-signal	3.2us ON-signal3.2us ON-signal

Table 2 does not indicate CP separately. In fact, CP + 3.2us including CP may point to one 1-bit information. That is, the 3.2us on signal can be viewed as a (CP + 3.2us) on signal. A 3.2us off signal can be seen as a (CP + 3.2us) off signal.

As another example, a symbol to which Manchester coding is applied may be represented as CP + 1.6us + CP + 1.6us or CP + 1.6us + 1.6us. The symbol to which the Manchester coding is applied may be generated as follows.

In the OOK transmission using the Wi-Fi transmitter, the time used for transmitting one bit (or symbol) except for the guard interval of the transmission signal is 3.2 us. In this case, if Manchester coding is applied, a signal size transition should occur at 1.6us. That is, each sub-information having a length of 1.6us should have a value of 0 or 1, and may configure a signal in the following manner.

* Information 0-> 1 0 (each can be referred to as sub information 1 0 or sub symbol 1 (ON) 0 (OFF))

First 1.6us (sub information 1 or sub symbol 1): Sub information 1 may have a value of beta * ones (1, K). Beta is a power normalization factor and may be, for example, 1 / sqrt (ceil (K / 2)).

In addition, a specific sequence is applied in units of two squares to all available subcarriers (eg, 13 subcarriers) to generate a symbol to which Manchester coding is applied. That is, even-numbered subcarriers of a particular sequence are nulled to zero. That is, in a particular sequence, coefficients may exist at intervals of two cells. For example, suppose that 13 subcarriers are used to construct an on-signal, a particular sequence with coefficients spaced two spaces apart is {a 0 b 0 c 0 d 0 e 0 f 0 g}, {0 a 0 b 0 c 0 d 0 e 0 f 0} or {a 0 b 0 c 0 0 0 d 0 e 0 method. At this time, a, b, c, d, e, f, g is 1 or -1.

That is, the transmitter maps a specific sequence to K consecutive subcarriers of 64 subcarriers (for example, 33-floor (K / 2): 33 + ceil (K / 2) -1) and the remaining subcarriers. IFFT is performed by setting the coefficient to 0. In this way, signals in the time domain can be generated. The signal in the time domain is a 3.2us long signal having a 1.6us period because coefficients exist at intervals of two spaces in the frequency domain. One of the first or second 1.6us period signals can be selected and used as sub information 1.

Second 1.6us (sub information 0 or sub symbol 0): The sub information 0 may have a value of zeros (1, K). Similarly, the transmitter maps a specific sequence to K consecutive subcarriers of 64 subcarriers (eg, 33-floor (K / 2): 33 + ceil (K / 2) -1) and performs IFFT. The signal in the time domain can be generated. The sub information 0 may correspond to a 1.6us off signal. The 1.6us off signal can be generated by setting all coefficients to zero.

One of the first or second 1.6us periodic signals of the signal in the time domain may be selected and used as the sub information 0. You can simply use the zeros (1,32) signal as subinformation zero.

* Information 1-> 0 1 (each can be referred to as sub information '0', '1' or sub symbol 0 (OFF) 1 (ON))

Since information 1 is also divided into the first 1.6us (sub information 0) and the second 1.6us (sub information 1), a signal corresponding to each sub information may be configured in the same manner as the information 0 is generated.

By using a technique of generating information 0 and information 1 using Manchester coding, it is possible to prevent the off symbol from continuing as compared to the conventional method. Therefore, a coexistence problem with an existing Wi-Fi device may not occur. The coexistence problem is a problem caused by transmitting a signal by determining that another device is a channel idle state due to a continuous off symbol. If only OOK modulation is used, for example, the off-symbol may be contiguous with the sequence 100001 or the like, but if Manchester coding is used, the off-symbol cannot be contiguous with the sequence 100101010110.

According to the above description, the sub information may be referred to as a 1.6us information signal. The 1.6us information signal may be a 1.6us on signal or a 1.6 off signal. The 1.6us on signal and the 1.6 off signal may have different sequences applied to each subcarrier.

CP can be used by adopting a specific length from the back of the 1.6us of the information signal immediately after. At this time, CP may be 0.4us or 0.8us. This length is equal to the guard interval of 802.11ac.

Accordingly, one bit information corresponding to one Manchester coded symbol may be represented as shown in the following table.

Information ‘0’Information ‘0’	Information ‘1’Information ‘1’
1.6us ON-signal + 1.6us OFF-signal1.6us ON-signal + 1.6us OFF-signal	1.6us OFF-signal + 1.6us ON-signal1.6us OFF-signal + 1.6us ON-signal
혹은 1.6us OFF-signal + 1.6us ON-signalOr 1.6us OFF-signal + 1.6us ON-signal	혹은 1.6us ON-signal + 1.6us OFF-signal Or 1.6us ON-signal + 1.6us OFF-signal

Table 3 does not indicate CP separately. In fact, CP + 1.6us + CP + 1.6us or CP + 1.6us + 1.6us including CP may indicate one 1-bit information. That is, in the former case, the 1.6us on signal and the 1.6us off signal may be regarded as the (CP + 1.6us) on signal and the (CP + 1.6us) off signal.

As another example, a method of constructing a wake-up packet by repeating symbols for performance improvement is proposed.

The symbol repetition technique is applied to the wakeup payload 724. The symbol repetition technique means repetition of a time signal after insertion of an IFFT and a cyclic prefix (CP) of each symbol. Thus, the length (time) of the wakeup payload 724 is doubled.

That is, it is proposed to apply a symbol representing information such as information 0 or information 1 to a specific sequence and to repeat the configuration as follows.

Option 1: Information 0 and Information 1 can be repeatedly represented by the same symbol.

Info 0-> 0 0 (repeat Info 0 twice)

-Info 1-> 1 1 (repeat Info 1 twice)

Option 2: Information 0 and Information 1 can be repeatedly represented by different symbols.

Information 0-> 0 1 or 1 0 (repeat info 0 and info 1)

Info 1-> 1 0 or 0 1 (repeat Info 1 and Info 0)

Hereinafter, a method of decoding by a receiving apparatus a signal transmitted by applying a symbol repetition technique to the transmitting apparatus will be described.

The transmitted signal may correspond to a wakeup packet, and a method of decoding the wakeup packet can be largely divided into two types. The first is non-coherent detection and the second is coherent detection. In non-coherent detection, the phase relationship between the transmitter and receiver signals is not fixed. Thus, the receiver does not need to measure and adjust the phase of the received signal. In contrast, the coherent detection method requires that the phase of the signal between the transmitter and the receiver be aligned.

The receiver includes the low power wake-up receiver described above. The low power wake-up receiver may decode a packet (wake-up packet) transmitted using an OOK modulation scheme using an envelope detector to reduce power consumption.

The envelope detector measures and decodes the power or magnitude of the received signal. The receiver sets a threshold based on the power or magnitude measured by the envelope detector. When decoding the symbol to which the OOK is applied, it is determined as information 1 if it is greater than or equal to the threshold value, and as information 0 when it is smaller than the threshold value.

The method of decoding a symbol to which the symbol repetition technique is applied is as follows. In the option 1, the receiving apparatus may use the wake-up preamble 722 to calculate a power when symbol 1 (symbol including information 1) is transmitted and determine the threshold.

In detail, the average power of the two symbols may be determined to determine information 1 (1 1) if the value is equal to or greater than the threshold value, and to determine information 0 (0 0) if the value is less than the threshold value.

In addition, in option 2, information may be determined by comparing the power of two symbols without determining a threshold.

Specifically, if information 1 is composed of 0 1 and information 0 is composed of 1 0, it is determined as information 0 if the power of the first symbol is greater than the power of the second symbol. On the contrary, if the power of the first symbol is less than the power of the second symbol, it is determined as information 1.

This is because the order of symbols can be reconstructed by an interleaver. The interleaver may be applied in units of specific symbol numbers below the packet unit.

In addition, not only two symbols but also n can be extended as follows. 28 illustrates various examples of a symbol repetition technique of repeating n symbols according to the present embodiment.

* Option 1: As shown in FIG. 28, information 0 and information 1 may be repeatedly represented by the same symbol n times.

-Information 0-> 0 0 ... 0 (repeat info 0 n times)

-Information 1-> 1 1 ... 1 (repeat information 1 n times)

* Option 2: As shown in FIG. 28, the information 0 and the information 1 may be repeatedly displayed n times with different symbols.

-Information 0-> 0 1 0 1 ... or 1 0 1 0 ... (repeat info 0 and info 1 n times with each other)

-Info 1-> 1 0 1 0 ... or 0 1 0 1 ... (repeat info 1 and info 0 n times with each other)

Option 3: As shown in FIG. 28, half of the symbol may be composed of information 0 and the other half may be composed of information 1 to represent n symbols.

-Information 0-> 0 0 ... 1 1 ... or 1 1 ... 0 0 ... (n / 2 symbols consist of information 0, the remaining n / 2 symbols consist of information 1 do)

-Information 1-> 1 1 ... 0 0 ... or 0 0 ... 1 1 ... (n / 2 symbols consist of information 0, the remaining n / 2 symbols consist of information 1 do)

* Option 4: When n is odd as shown in FIG. 28, n symbols may be represented by dividing the number of symbols 1 (symbol including information 1) and the number of symbols 0 (symbol including information 0).

Information 0-> n symbols where the number of symbols 1 is odd and the number of symbols 0 is even, or n symbols where the number of symbols 1 is even and the number of symbols 0 is odd

Information 1-> n symbols where the number of symbols 0 is odd and the number of symbols 1 is even, or n symbols where the number of symbols 0 is even and the number of symbols 1 is odd

In addition, the order of symbols may be reconstructed by the interleaver. The interleaver may be applied in units of packets and specific symbols.

In addition, as described above, the receiving apparatus may determine whether the information is 0 or 1 by determining the threshold value and comparing the powers of the n symbols.

However, the use of consecutive symbol 0 (or off symbol) may cause a coexistence problem with an existing Wi-Fi device and / or another device. The coexistence problem is a problem caused by transmitting a signal by determining that another device is a channel idle state due to a continuous off symbol. Thus, the option 2 scheme may be preferred as it is desirable to avoid the use of consecutive off symbols to solve the leveling problem.

In addition, it can be extended in a manner of expressing m information using n symbols. In this case, the first or last m is represented by 0 (OFF) or 1 (ON) symbols depending on the information, and the nm or 0 (OFF) or 1 (ON) redundant symbols are formed consecutively before or after. can do.

For example, if a code rate of 3/4 is applied to the information 010, it may be 1,010 or 010,1 or 0,010 or 010,0. However, in order to prevent the use of consecutive off symbols, it may be desirable to apply a code rate of 1/2 or less.

In this embodiment as well, the order of symbols can be reconstructed by the interleaver. The interleaver may be applied in units of packets and specific symbols.

Hereinafter, various embodiments of a symbol to which the symbol repetition technique is applied will be described.

In general, a symbol to which the symbol repetition technique is applied may be represented by n (CP + 3.2us) or CP + n (1.6us).

As shown in FIG. 28, n (n> = 2) information bits (symbols) are used to represent 1 bit, and a specific sequence is applied to all available subcarriers (for example, 13), and IFFT is taken to obtain 3.2us of information. Form a signal (symbol).

Accordingly, 1 bit information corresponding to a symbol to which a general symbol repetition technique is applied may be represented as shown in the following table.

Information ‘0’Information ‘0’	Information ‘1’Information ‘1’
모두 3.2us OFF-signal3.2us OFF-signal	모두 3.2us ON-signal3.2us ON-signal
혹은 특정 두 개의 연속된 signal이3.2us ON-signal + 3.2us OFF-signal,나머지 signal 모두 ON 혹은 모두 OFFOr two specific consecutive signals are 3.2us ON-signal + 3.2us OFF-signal, all other signals are ON or all OFF	혹은 특정 두 개의 연속된 signal이3.2us OFF-signal + 3.2us ON-signal,나머지 signal 모두 ON 혹은 모두 OFF Or two specific consecutive signals are 3.2us OFF-signal + 3.2us ON-signal, all other signals are ON or all OFF
혹은 특정 두 개의 연속된 signal이3.2us OFF-signal + 3.2us ON-signal,나머지 signal 모두 ON 혹은 모두 OFF Or two specific consecutive signals are 3.2us OFF-signal + 3.2us ON-signal, all other signals are ON or all OFF	혹은 특정 두 개의 연속된 signal이3.2us ON-signal + 3.2us OFF-signal,나머지 signal 모두 ON 혹은 모두 OFFOr two specific consecutive signals are 3.2us ON-signal + 3.2us OFF-signal, all other signals are ON or all OFF
혹은 특정 위치에 놓인 특정 개수(혹은 ceil(n/2개) 혹은 floor(n/2)개)는 3.2us OFF-signal나머지는 3.2us ON-signalEx) ON+OFF+ON+OFF…Or a certain number (or ceil (n / 2) or floor (n / 2)) placed in a specific position is 3.2us OFF-signal, 3.2us ON-signalEx) ON + OFF + ON + OFF…	혹은 특정 위치에 놓인 특정 개수(혹은 ceil(n/2개) 혹은 floor(n/2)개)는 3.2us ON-signal나머지는 3.2us OFF-signalEx) OFF+ON+OFF+ON+OFF…Or a certain number (or ceil (n / 2) or floor (n / 2)) placed in a specific position is 3.2us ON-signal, 3.2us OFF-signalEx) OFF + ON + OFF + ON + OFF…

Table 4 does not indicate CP separately. In fact, n pieces (CP + 3.2us) including CPs or CP + n pieces (3.2us) may indicate one 1-bit information. That is, in the case of n (CP + 3.2us), the 3.2us on signal may be viewed as a (CP + 3.2us) on signal, and the 3.2us off signal may be viewed as a (CP + 3.2us) off signal.

As another example, a symbol to which the symbol repetition technique is applied may be represented as CP + 3.2us + CP + 3.2us or CP + 3.2us + 3.2us.

According to the above embodiment, two information signals (symbols) are used to represent one bit and a specific sequence is applied to all available subcarriers (for example, thirteen), and then IFFT is taken to generate an information signal (symbol) of 3.2us. Form.

Accordingly, one bit information corresponding to a symbol to which the symbol repetition technique is applied may be represented as shown in the following table.

Information ‘0’Information ‘0’	Information ‘1’Information ‘1’
3.2us OFF-signal + 3.2us OFF-signal3.2us OFF-signal	3.2us ON-signal + 3.2us ON-signal3.2us ON-signal + 3.2us ON-signal
혹은 3.2us ON-signal + 3.2us OFF-signalOr 3.2us ON-signal + 3.2us OFF-signal	혹은 3.2us OFF-signal + 3.2us ON-signal Or 3.2us OFF-signal + 3.2us ON-signal
혹은 3.2us OFF-signal + 3.2us ON-signalOr 3.2us OFF-signal + 3.2us ON-signal	혹은 3.2us ON-signal + 3.2us OFF-signal Or 3.2us ON-signal + 3.2us OFF-signal

Table 5 does not indicate CP separately. In fact, CP + 3.2us + CP + 3.2us or CP + 3.2us + 3.2us, including CP, may point to one 1-bit information. That is, in the case of CP + 3.2us + CP + 3.2us, the 3.2us on signal can be viewed as a (CP + 3.2us) on signal, and the 3.2us off signal can be viewed as a (CP + 3.2us) off signal. .

As another example, a symbol to which the symbol repetition technique is applied may be represented as CP + 3.2us + CP + 3.2us + CP + 3.2us or CP + 3.2us + 3.2us + 3.2us.

According to the above embodiment, three information signals (symbols) are used to represent one bit and a specific sequence is applied to all available subcarriers (eg, thirteen), and then IFFT is taken to generate an information signal (symbol) of 3.2us. Form.

Information ‘0’Information ‘0’	Information ‘1’Information ‘1’
3.2us OFF-signal + 3.2us OFF-signal + 3.2us OFF-signal3.2us OFF-signal + 3.2us OFF-signal + 3.2us OFF-signal	3.2us ON-signal + 3.2us ON-signal + 3.2us ON-signal3.2us ON-signal + 3.2us ON-signal + 3.2us ON-signal
혹은 3.2us ON-signal + 3.2us ON-signal + 3.2us OFF-signalOr 3.2us ON-signal + 3.2us ON-signal + 3.2us OFF-signal	혹은 3.2us ON-signal + 3.2us OFF-signal + 3.2us ON-signal Or 3.2us ON-signal + 3.2us OFF-signal + 3.2us ON-signal
혹은 3.2us ON-signal + 3.2us OFF-signal + 3.2us ON-signalOr 3.2us ON-signal + 3.2us OFF-signal + 3.2us ON-signal	혹은 3.2us ON-signal + 3.2us ON-signal + 3.2us OFF-signal Or 3.2us ON-signal + 3.2us ON-signal + 3.2us OFF-signal
혹은 3.2us ON-signal + 3.2us OFF-signal + 3.2us ON-signalOr 3.2us ON-signal + 3.2us OFF-signal + 3.2us ON-signal	혹은 3.2us OFF-signal + 3.2us ON-signal + 3.2us OFF-signal Or 3.2us OFF-signal + 3.2us ON-signal + 3.2us OFF-signal

Table 6 does not indicate CP separately. In fact, CP + 3.2us + CP + 3.2us + CP + 3.2us or CP + 3.2us + 3.2us + 3.2us, including CP, may point to one 1-bit information. That is, in the case of CP + 3.2us + CP + 3.2us + CP + 3.2us, the 3.2us on signal can be viewed as a (CP + 3.2us) on signal, and the 3.2us off signal is a (CP + 3.2us) off It can be seen as a signal.

As another example, a symbol to which the symbol repetition technique is applied may be represented as CP + 3.2us + CP + 3.2us + CP + 3.2us + CP + 3.2us or CP + 3.2us + 3.2us + 3.2us + 3.2us.

According to the above embodiment, four information signals (symbols) are used to represent one bit and a specific sequence is applied to all available subcarriers (for example, thirteen), and then IFFT is taken to generate an information signal (symbol) of 3.2us. Form.

Information ‘0’Information ‘0’	Information ‘1’Information ‘1’
3.2us OFF-signal + 3.2us OFF-signal + 3.2us OFF-signal + 3.2us OFF-signal3.2us OFF-signal + 3.2us OFF-signal + 3.2us OFF-signal + 3.2us OFF-signal	3.2us ON-signal + 3.2us ON-signal + 3.2us ON-signal + 3.2us ON-signal3.2us ON-signal + 3.2us ON-signal + 3.2us ON-signal + 3.2us ON-signal
혹은 3.2us ON-signal + 3.2us ON-signal + 3.2us ON-signal + 3.2us OFF-signalOr 3.2us ON-signal + 3.2us ON-signal + 3.2us ON-signal + 3.2us OFF-signal	혹은 3.2us ON-signal + 3.2us ON-signal + 3.2us OFF-signal + 3.2us ON-signal Or 3.2us ON-signal + 3.2us ON-signal + 3.2us OFF-signal + 3.2us ON-signal
혹은3.2us ON-signal + 3.2us ON-signal + 3.2us OFF-signal + 3.2us ON-signalOr 3.2us ON-signal + 3.2us ON-signal + 3.2us OFF-signal + 3.2us ON-signal	혹은 3.2us ON-signal + 3.2us ON-signal + 3.2us ON-signal + 3.2us OFF-signal Or 3.2us ON-signal + 3.2us ON-signal + 3.2us ON-signal + 3.2us OFF-signal
혹은 3.2us ON-signal + 3.2us ON-signal + 3.2us OFF-signal+ 3.2us ON-signal Or 3.2us ON-signal + 3.2us ON-signal + 3.2us OFF-signal + 3.2us ON-signal	혹은 3.2us ON-signal + 3.2us OFF-signal + 3.2us ON-signal+ 3.2us ON-signal Or 3.2us ON-signal + 3.2us OFF-signal + 3.2us ON-signal + 3.2us ON-signal
혹은 3.2us ON-signal + 3.2us OFF-signal + 3.2us ON-signal+ 3.2us ON-signal Or 3.2us ON-signal + 3.2us OFF-signal + 3.2us ON-signal + 3.2us ON-signal	혹은 3.2us ON-signal + 3.2us ON-signal + 3.2us OFF-signal+ 3.2us ON-signal Or 3.2us ON-signal + 3.2us ON-signal + 3.2us OFF-signal + 3.2us ON-signal
혹은 3.2us ON-signal + 3.2us OFF-signal + 3.2us ON-signal+ 3.2us OFF-signal Or 3.2us ON-signal + 3.2us OFF-signal + 3.2us ON-signal + 3.2us OFF-signal	혹은 3.2us OFF-signal + 3.2us ON-signal + 3.2us OFF-signal+ 3.2us ON-signal Or 3.2us OFF-signal + 3.2us ON-signal + 3.2us OFF-signal + 3.2us ON-signal
혹은 3.2us ON-signal + 3.2us ON-signal + 3.2us OFF-signal+ 3.2us OFF-signalOr 3.2us ON-signal + 3.2us ON-signal + 3.2us OFF-signal + 3.2us OFF-signal	혹은 3.2us OFF-signal + 3.2us OFF-signal + 3.2us ON-signal+ 3.2us ON-signalOr 3.2us OFF-signal + 3.2us OFF-signal + 3.2us ON-signal + 3.2us ON-signal
혹은 3.2us OFF-signal + 3.2us OFF-signal + 3.2us ON-signal+ 3.2us ON-signalOr 3.2us OFF-signal + 3.2us OFF-signal + 3.2us ON-signal + 3.2us ON-signal	혹은 3.2us ON-signal + 3.2us ON-signal + 3.2us OFF-signal+ 3.2us OFF-signalOr 3.2us ON-signal + 3.2us ON-signal + 3.2us OFF-signal + 3.2us OFF-signal

Table 7 does not indicate CP separately. Indeed, CP + 3.2us + CP + 3.2us + CP + 3.2us + CP + 3.2us or CP + 3.2us + 3.2us + 3.2us + 3.2us, including CP, may point to one single bit of information. That is, in the case of CP + 3.2us + CP + 3.2us + CP + 3.2us + CP + 3.2us, the 3.2us on signal can be regarded as (CP + 3.2us) on signal and the 3.2us off signal is (CP + 3.2us) off signal.

As another example, a symbol to which Manchester coding is applied based on symbol repetition may be represented by n (CP + 1.6us + CP + 1.6us) or CP + n (1.6us + 1.6us).

According to the above embodiment, a symbol is repeated using a symbol repeated n (> = 2) times, and a specific sequence is applied to all available subcarriers (for example, 13), and the remaining coefficients of 0 are applied. By setting IFFT, 3.2us of signal with 1.6us period is generated. Take one of these and set it as a 1.6us information signal (symbol).

The sub information may be called a 1.6us information signal. The 1.6us information signal may be a 1.6us on signal or a 1.6 off signal. The 1.6us on signal and the 1.6 off signal may have different sequences applied to each subcarrier. The 1.6us off signal can be generated by applying all coefficients to zero.

Accordingly, 1 bit information corresponding to a symbol to which Manchester coding is applied based on the symbol repetition may be represented as shown in the following table.

Information ‘0’Information ‘0’	Information ‘1’Information ‘1’
(1.6us ON-signal + 1.6us OFF-signal) n번 반복(1.6us ON-signal + 1.6us OFF-signal) Repeat n times	(1.6us OFF-signal + 1.6us ON-signal) n번 반복(1.6us OFF-signal + 1.6us ON-signal) Repeat n times
혹은 (1.6us OFF-signal + 1.6us ON-signal) n번 반복Or (1.6us OFF-signal + 1.6us ON-signal) n times	혹은 (1.6us ON-signal + 1.6us OFF-signal) n번 반복 Or (1.6us ON-signal + 1.6us OFF-signal) n times
(1.6us ON-signal + 1.6us OFF-signal)+ (1.6us OFF-signal + 1.6us ON-signal) floor(n/2)반복+ 필요시 (1.6us ON-signal + 1.6us OFF-signal)(1.6us ON-signal + 1.6us OFF-signal) + (1.6us OFF-signal + 1.6us ON-signal) floor (n / 2) Repeat + if necessary (1.6us ON-signal + 1.6us OFF-signal)	(1.6us OFF-signal + 1.6us ON-signal)+ (1.6us ON-signal + 1.6us OFF-signal) floor(n/2)반복+ 필요시 (1.6us OFF-signal + 1.6us ON-signal)(1.6us OFF-signal + 1.6us ON-signal) + (1.6us ON-signal + 1.6us OFF-signal) floor (n / 2) Repeat + if necessary (1.6us OFF-signal + 1.6us ON-signal)
(1.6us OFF-signal + 1.6us ON-signal)+ (1.6us ON-signal + 1.6us OFF-signal) floor(n/2)반복+ 필요시 (1.6us OFF-signal + 1.6us ON-signal)(1.6us OFF-signal + 1.6us ON-signal) + (1.6us ON-signal + 1.6us OFF-signal) floor (n / 2) Repeat + if necessary (1.6us OFF-signal + 1.6us ON-signal)	(1.6us ON-signal + 1.6us OFF-signal)+ (1.6us OFF-signal + 1.6us ON-signal) floor(n/2)반복+ 필요시 (1.6us ON-signal + 1.6us OFF-signal)(1.6us ON-signal + 1.6us OFF-signal) + (1.6us OFF-signal + 1.6us ON-signal) floor (n / 2) Repeat + if necessary (1.6us ON-signal + 1.6us OFF-signal)

Table 8 does not indicate CP separately. In fact, n (CP + 1.6us + CP + 1.6us) or CP + n (1.6us + 1.6us) including CP may indicate one 1-bit information. That is, in the case of n (CP + 1.6us + CP + 1.6us), the 1.6us on signal can be viewed as a (CP + 1.6us) on signal, and the 1.6us off signal is a (CP + 1.6us) off signal. Can be seen as.

Like the embodiments described above, the symbol repetition technique can satisfy the range requirement of low power wake-up communication. When only the OOK method is applied, the data rate for one symbol is 250 Kbps (4us). At this time, if the symbol is repeated twice using the symbol repetition technique, the data rate may be 125 Kbps (8us), and if the fourth repetition is performed, the data rate may be 62.5 Kbps (16us), and if the eight times are repeated, the data rate may be 31.25Kbps (32us). have. In the case of low-power wake-up communication, if there is no BCC, the symbol needs to be repeated eight times to satisfy the range requirement.

Hereinafter, various embodiments of a symbol to which a symbol reduction technique is applied among symbol types that can be used in the WUR will be described.

According to the embodiment of FIG. 29, as the m value increases, the symbol is further reduced to reduce the length of the symbol carrying one piece of information. When m = 2, the length of a symbol carrying one piece of information becomes CP + 1.6us. When m = 4, the length of a symbol carrying one piece of information becomes CP + 0.8us. When m = 8, the length of a symbol carrying one piece of information becomes CP + 0.4us.

As the length of the symbol decreases, a high data rate can be ensured. If only the OOK scheme is applied, the data rate for one symbol is 250 Kbps (4us). In this case, using m = 2, the data rate is 500 Kbps (2us), if m = 4, the data rate is 1Mbps (1us), if m = 8 data rate can be 2Mbps (0.5us). .

For example, a symbol to which a symbol reduction technique is generally applied may be represented by CP + 3.2us / m (m = 2,4,8,16,32, ...) (option 1).

As shown in option 1 of FIG. 29, a symbol is applied to the symbol reduction technique to represent one bit, and a specific sequence is applied to every available subcarrier (for example, 13) in units of m columns, and the rest is set to a coefficient of zero. do. Subsequently, if IFFT is applied to the subcarrier to which the specific sequence is applied, a 3.2us signal having a 3.2us / m period is generated. Take one of these and map it to the 3.2us / m information signal (information 1).

For example, if a specific sequence is applied in units of two columns (m = 2) to 13 subcarriers, the on signal may be configured as follows.

On signal (information 1): {a 0 b 0 c 0 d 0 e 0 f 0 g} or {0 a 0 b 0 c 0 d 0 e 0 f 0}, where a, b, c, d, e, f, g is 1 or -1.

As another example, if a specific sequence is applied to 13 subcarriers in units of four squares (m = 4), the on signal may be configured as follows.

On signal (Info 1): {a 0 0 0 b 0 0 0 c 0 0 0 d} or {0 a 0 0 0 b 0 0 0 c 0 0 0} or {0 0 a 0 0 0 b 0 0 0 c 0 0} or {0 0 0 a 0 0 0 b 0 0 0 c 0} or {0 0 a 0 0 0 0 0 0 0 b 0 0}, where a, b, c, d is 1 or -1.

As another example, if a specific sequence is applied to 13 subcarriers by 8 columns (m = 8), the on signal may be configured as follows.

On signal (information 1): {a 0 0 0 0 0 0 0 b 0 0 0 0} or {0 a 0 0 0 0 0 0 0 b 0 0 0} or {0 0 a 0 0 0 0 0 0 0 0 b 0 0} or {0 0 0 a 0 0 0 0 0 0 0 b 0}, or {0 0 0 0 a 0 0 0 0 0 0 0 b}, where a and b are 1 or -1 .

The 3.2us / m information signal is divided into a 3.2us / m on signal and a 3.2us / m off signal. In addition, different sequences may be applied to the (usable) subcarriers for the 3.2us / m on signal and the 3.2us / m off signal, respectively. A 3.2us / m off signal can be generated by applying all coefficients to zero.

CP can be used by adopting a specific length from the back of the information signal 3.2us / m immediately behind. At this time, CP may be 0.4us or 0.8us. This length is equal to the guard interval of 802.11ac. However, when m = 8, the CP cannot be 0.8us. Alternatively, CP may be 0.1us or 0.2us, or another value.

Accordingly, 1 bit information corresponding to a symbol to which a general symbol reduction technique is applied may be represented as shown in the following table.

Information ‘0’Information ‘0’	Information ‘1’Information ‘1’
3.2us/m OFF-signal3.2us / m OFF-signal	3.2us/m ON-signal3.2us / m ON-signal

CP is not shown separately in Table 9. In fact, CP + 3.2us / m including CP may indicate one 1-bit information. That is, the 3.2us / m on signal may be viewed as a CP + 3.2us / m on signal, and the 3.2us / m off signal may be viewed as a CP + 3.2us / m off signal.

As another example, a symbol to which the symbol reduction technique is applied may be represented by CP + 3.2us / m + CP + 3.2us / m (m = 2,4,8) (option 2).

In the OOK transmission using the Wi-Fi transmitter, the time used for transmitting one bit (or symbol) except for the guard interval of the transmission signal is 3.2 us. At this time, if the symbol reduction technique is applied, the time used for one bit transmission is 3.2us / m. However, in this embodiment, the time used for transmitting one bit is repeated as 3.2us / m + 3.2us / m by repeating a symbol to which the symbol reduction technique is applied, and the signal between 3.2us / m signals is also used by using the characteristics of Manchester coding. A transition in size was allowed to occur. That is, each sub-information having a length of 3.2us / m should have a value of 0 or 1, and may configure a signal in the following manner.

First 3.2us / m signal (sub-information 1 or sub-symbol 1): A specific sequence in m-column for all available subcarriers (e.g. 13 subcarriers) to generate symbols with symbol reduction Apply. That is, in a particular sequence, coefficients may exist at intervals of m columns.

The transmitter maps a specific sequence to K consecutive subcarriers of 64 subcarriers and sets a coefficient to 0 for the remaining subcarriers to perform IFFT. In this way, signals in the time domain can be generated. Since the signal in the time domain has coefficients at intervals of m in the frequency domain, a 3.2us signal having a 3.2us / m period is generated. You can take one of these and use it as a 3.2us / m on signal (sub information 1).

Second 3.2us / m signal (sub information 0 or subsymbol 0): As with the first 3.2us / m signal, the transmitter maps a particular sequence to K consecutive subcarriers of 64 subcarriers, Can be generated to generate a time domain signal. The sub information 0 may correspond to a 3.2 us / m off signal. The 3.2us / m off signal can be generated by setting all coefficients to zero.

One of the first or second 3.2us / m periodic signals of the signal in the time domain may be selected and used as the sub information 0.

-Since information 1 is also divided into the first 3.2us / m signal (sub information 0) and the second 3.2us / m signal (sub information 1), the signal corresponding to each sub information is generated in the same way as information 0 is generated. Can be configured.

In addition, information 0 may be configured as 01 and information 1 may be configured as 10.

As in option 2 of FIG. 29, 1-bit information corresponding to a symbol to which a symbol reduction technique is applied may be represented as shown in the following table.

Information ‘0’Information ‘0’	Information ‘1’Information ‘1’
3.2us/m OFF-signal + 3.2us/m ON-signal혹은3.2us/m ON-signal + 3.2us/m OFF-signal 3.2us / m OFF-signal + 3.2us / m ON-signal or 3.2us / m ON-signal + 3.2us / m OFF-signal	3.2us/m ON-signal + 3.2us/m OFF-signal혹은3.2us/m OFF-signal + 3.2us/m ON-signal3.2us / m ON-signal + 3.2us / m OFF-signal or 3.2us / m OFF-signal + 3.2us / m ON-signal

In Table 10, CP is not separately indicated. In fact, CP + 3.2us / m including CP may indicate one 1-bit information. That is, the 3.2us / m on signal may be viewed as a CP + 3.2us / m on signal, and the 3.2us / m off signal may be viewed as a CP + 3.2us / m off signal.

Embodiments illustrated by option 1 and option 2 of FIG. 29 may be generalized as shown in the following table.

	Information ‘0’Information ‘0’	Information ‘1’Information ‘1’
Option 1(m=2,4,8)Option 1 (m = 2,4,8)	2us OFF-signal2us OFF-signal	2us ON-signal2us ON-signal
	1us OFF-signal1us OFF-signal	1us ON-signal1us ON-signal
	0.5us OFF-signal0.5us OFF-signal	0.5us ON-signal0.5us ON-signal
Option 2(m=4,8)Option 2 (m = 4,8)	1us OFF-signal + 1us ON-signal 혹은1us ON-signal + 1us OFF-signal 1us OFF-signal + 1us ON-signal or 1us ON-signal + 1us OFF-signal	1us ON-signal + 1us OFF-signal 혹은1us OFF-signal + 1us ON-signal1us ON-signal + 1us OFF-signal or 1us OFF-signal + 1us ON-signal
Option 2(m=4,8)Option 2 (m = 4,8)	0.5us OFF-signal + 0.5us ON-signal 혹은0.5us ON-signal + 0.5us OFF-signal 0.5us OFF-signal + 0.5us ON-signal or 0.5us ON-signal + 0.5us OFF-signal	0.5us ON-signal + 0.5us OFF-signal 혹은0.5us OFF-signal + 0.5us ON-signal0.5us ON-signal + 0.5us OFF-signal or 0.5us OFF-signal + 0.5us ON-signal

Table 11 shows each signal in length including CP. That is, CP + 3.2us / m including the CP may indicate one 1-bit information.

For example, when m = 4 in Option 2, a symbol carrying one piece of information becomes CP + 0.8us, and thus a 1us off signal or 1us on signal is composed of a CP (0.2us) + 0.8us signal. In Option 2, since Manchester coding is applied and symbols are repeated, the data rate of one information can be 500 Kbps when m = 4.

As another example, when m = 8 in Option 2, a symbol carrying one piece of information becomes CP + 0.4us, and thus a 0.5us off signal or a 0.5us on signal is composed of a CP (0.1us) + 0.4us signal. In Option 2, since Manchester coding is applied and symbols are repeated, the data rate of one information may be 1Mbps when m = 8.

In the table below, the data rates that can be secured through the above-described embodiments are compared with each other.

CPCP	기본 symbol (실시예1)(CP+3.2us)Default symbol (Example 1) (CP + 3.2us)	Man. Symbol (실시예2)(CP+1.6+CP+1.6)Man. Symbol (Example 2) (CP + 1.6 + CP + 1.6)	Man. Symbol (실시예3)(CP+1.6+1.6)Man. Symbol (Example 3) (CP + 1.6 + 1.6)
0.4us0.4us	277.8277.8	250.0250.0	277.8277.8
0.8us0.8us	250.0250.0	208.3208.3	250.0250.0

CPCP	Symbol rep.n개(CP+3.2us)Symbol rep.n (CP + 3.2us)			Symbol rep.CP+n개(3.2us)CP rep.CP + n (3.2us)			Man. symbol rep.n개(CP+1.6us+CP+1.6us)Man. symbol rep.n (CP + 1.6us + CP + 1.6us)
CPCP	n=2 (실시예4)n = 2 (Example 4)	n=3 (실시예 5)n = 3 (Example 5)	n=4 (실시예 6)n = 4 (Example 6)	n=2 (실시예7)n = 2 (Example 7)	n=3 (실시예8)n = 3 (Example 8)	n=4 (실시예 9)n = 4 (Example 9)	n=2 (실시예 10)n = 2 (Example 10)	n=3 (실시예 11)n = 3 (Example 11)	n=4 (실시예 12)n = 4 (Example 12)
0.4us0.4us	138.9138.9	92.692.6	69.469.4	147.1147.1	100.0100.0	75.875.8	125.0125.0	83.383.3	62.562.5
0.8us0.8us	125.0125.0	83.383.3	62.562.5	138.9138.9	96.296.2	73.573.5	104.2104.2	69.469.4	52.152.1

CPCP	Man. symbol rep.CP+n개(1.6us+1.6us)Man. CP + n symbols (1.6us + 1.6us)			Symbol reductionCP+3.2us/mSymbol reductionCP + 3.2us / m
CPCP	n=2 (실시예13)n = 2 (Example 13)	n=3 (실시예 14)n = 3 (Example 14)	n=4 (실시예 15)n = 4 (Example 15)	m=2 (실시예16)m = 2 (Example 16)	m=4 (실시예17)m = 4 (Example 17)	m=8 (실시예18)m = 8 (Example 18)
0.4us0.4us	147.1147.1	100.0100.0	75.875.8	500.0500.0	833.3833.3	1250.01250.0
0.8us0.8us	138.9138.9	96.296.2	73.573.5	416.7416.7	625.0625.0	NANA

CPCP	Symbol reductionCP+3.2us/mSymbol reductionCP + 3.2us / m		Man. symbol rep. w/ Man.CP+3.2us/m+CP+3.2us/mMan. symbol rep. w / Man.CP + 3.2us / m + CP + 3.2us / m
CPCP	m=4m = 4	m=8m = 8	m=4m = 4	m=8m = 8
0.1us0.1us	1111.11111.1	20002000	555.6555.6	10001000
0.2us0.2us	10001000	1666.71666.7	500500	833.3833.3

Hereinafter, a method of transmitting a WUR frame using a high efficiency PPDU (HEW PPDU) or a HEW PPDU according to the 802.11ax standard in an 802.11ba system is proposed.

Wake-up frames can be sent using narrow bands for power consumption or performance gain. Meanwhile, in 802.11ax, the OFDMA technique is reflected as a mandatory feature, and when transmitting the HE MU PPDU, the HE-SIG-B includes allocation information about the RU to which each user data is transmitted. In this case, there may be an RU that is not assigned to an ax STA. This RU is a narrow band 26-tone RU and may have the most optimized RU size for wakeup frame transmission among OFDMA RU sizes. In this specification, a scheme of simultaneously transmitting a wake-up frame in an 11ax PPDU using a 26-tone RU not allocated to an ax STA is proposed.

In a first embodiment, the wakeup frame may be transmitted using a central 26-tone RU in the 20 MHz band.

The wakeup frame may be transmitted over a specific 20 MHz band. This 20 MHz band may be a primary 20 MHz, a secondary 20 MHz, and may be a specific 20 MHz within the secondary 40 MHz or a specific 20 MHz within the 80 MHz band. This band may be determined during WUR negotiation or allocated to a different 20 MHz band for each WUR STA. A more detailed description will be described later.

After the 20 MHz band to which the WUR STA is allocated is determined, the AP may send a wake-up frame to the STA. In particular, the AP may transmit data to the WUR STA while simultaneously sending data to the ax STA using the HE MU PPDU format of 11ax. In this case, the HE MU PPDU may be in a 20 MHz, 40 MHz, 80 MHz, or 160 MHz format, and when the center 26-tone RU in the 20 MHz band to which the WUR STA is allocated is not assigned to the ax STA, the AP uses the center 26-tone RU. The wakeup frame may be sent to the corresponding WUR STA. For example, if the RU allocation of the 20 MHz band to which the WUR STA is assigned is as shown in the following table, the AP uses the center 26-tone RU of 20 MHz indicated to the corresponding WUR STA through the HE-SIG-B of the HE MU PPDU. Wake-up frames can be sent.

The RU allocation subfield (comprising 8 bits) may indicate an RU allocation pattern in a frequency band. Referring to Table 16, it can be seen that the RU allocation subfield (comprising 8 bits) indicates the RU allocation pattern when the central 26-tone RU is not allocated.

All WUR STAs may be assigned to a central 26-tone RU of primary 20 MHz. Since the primary 20 MHz is always used when transmitting the HE MU PPDU, there may be many opportunities for transmission of the wake-up frame.

Alternatively, all WUR STAs may be assigned to each 20 MHz centered 26-tone RU within 40 MHz of primary. In this case, it can be allocated using the ID (AID, PAID, MAC address, etc.) of the WUR STA. WUR STAs with even IDs may be assigned to a primary (or secondary) 20 MHz centered 26-tone RU and odd WUR STAs may be assigned to a secondary (or primary) 20 MHz centered 26-tone RU.

Alternatively, a WUR STA may be assigned to each 20 MHz centered 26-tone RU within the primary 80 MHz. If mod is defined as a modulo operation, a WUR STA with mod (ID, 4) = 0 can be assigned to a primary (or secondary) 20 MHz centered 26-tone RU and mod (ID, 4) = 1 The WUR STA may be assigned to a secondary (or primary) 20 MHz centered 26-tone RU. A WUR STA with mod (ID, 4) = 2 can be assigned to a 26-tone RU corresponding to a primary (or secondary) 20 MHz centered 26-tone RU at secondary 40 MHz and a WUR STA with mod (ID, 4) = 3 May be assigned to a 26-tone RU corresponding to a secondary (or primary) 20 MHz centered 26-tone RU at secondary 40 MHz.

Alternatively, a WUR STA may be assigned to each 20 MHz centered 26-tone RU within 80 + 80/160 MHz. A WUR STA with mod (ID, 8) = 0 can be assigned to a primary (or secondary) 20 MHz centered 26-tone RU and a WUR STA with mod (ID, 8) = 1 can be assigned to a secondary (or primary) 20 MHz centered 26 -Ton can be assigned to the RU. A WUR STA with mod (ID, 8) = 2 can be assigned to a 26-tone RU corresponding to a primary (or secondary) 20 MHz centered 26-tone RU at secondary 40 MHz and a WUR STA with mod (ID, 8) = 3 May be assigned to a 26-tone RU corresponding to a secondary (or primary) 20 MHz centered 26-tone RU at secondary 40 MHz. A WUR STA with mod (ID, 8) = 4 can be assigned to a 26-tone RU corresponding to a primary (or secondary) 20 MHz centered 26-tone RU at secondary 80 MHz and a WUR STA with mod (ID, 8) = 5 May be assigned to a 26-tone RU corresponding to a secondary (or primary) 20 MHz centered 26-tone RU at secondary 80 MHz. A WUR STA with mod (ID, 8) = 6 can be assigned to a 26-tone RU corresponding to a primary (or secondary) 20 MHz centered 26-tone RU of the two central 26-tone RUs corresponding to secondary 40 MHz at 80 MHz secondary. WUR STA with mod (ID, 8) = 7 will be assigned to a 26-tone RU corresponding to a secondary (or primary) 20 MHz centered 26-tone RU of the two centered 26-tone RUs corresponding to secondary 40 MHz Can be.

The central 26-ton RU allocated according to the mod results above may vary.

In a situation in which the AP transmits 40 MHz, 80 MHz, and 80 + 80/160 MHz HE MU PPDUs, there may be a case in which two or more RUs other than one of the central 26-tone RUs within each 20 MHz are not allocated to the ax STA. In this case, all empty 26-tone RUs (unassigned) can be used to make MU transmissions to the WUR STA.

In a second embodiment, the wake up frame may be transmitted using the center 26-tone RU in the 80 MHz band.

The wakeup frame may be transmitted using a center 26-tone RU of HE MU PPDU primary 80 MHz or secondary 80 MHz. The band used for each WUR STA may be determined at the time of WUR negotiation or may be allocated to a different band for each WUR STA. A more detailed description will be made later.

After the band to which the WUR STA is allocated is determined, the AP may transmit a wake-up frame to the STA using an 80 MHz or 80 + 80/160 MHz HE MU PPDU, and simultaneously transmit data to the ax STA. In the common field of HE-SIG-B of the HE MU PPDU of the following table, when the Center 26-tone RU subfield of 80 MHz to which the WUR STA is allocated is set to 0, the AP sends a corresponding 26-tone RU to the WUR STA. Can be used to send wake-up frames.

Referring to Table 17, when the Center 26-tone RU subfield included in the common field of the HE-SIG-B is set to 1, it indicates that the center 26-tone RU is allocated to the ax STA. It can be seen that the tone RU indicates that it is not assigned to the ax STA.

All WUR STAs may be assigned to a primary 80 MHz centered 26-tone RU. Since the 80 + 80 / 160MHz bandwidth at 11ax is an optional feature, it is reasonable because the secondary 80MHz is not likely to be used.

Conversely, all WUR STAs may be assigned to a secondary 80 MHz centered 26-tone RU. In this case, wake-up frame transmission is possible only if the HE MU PPDU is sent at 80 + 80 / 160MHz, and because there are so many RUs at 80 + 80 / 160MHz, the secondary 80MHz centered 26-tone RU is always used for WUR STA. Can be used.

Alternatively, the ID of the WUR STA (AID, PAID, MAC address, etc.) may be allocated to the primary or secondary 80-MHz center 26-tone RU. WUR STAs with even IDs can be assigned to a primary (or secondary) 80 MHz centered 26-tone RU, and odd WUR STAs can be assigned to a secondary (or primary) 80 MHz centered 26-tone RU have.

In a situation where an AP transmits an 80 + 80 / 160MHz HE MU PPDU, there may be a case in which not all 80MHz centered 26-tone RUs are allocated to an ax STA. In this case, the AP may make MU transmissions to the WUR STA using all of the central 26-tone RUs not assigned to the ax STA.

In a third embodiment, the wakeup frame may be transmitted using a center 26-tone RU in the 20 MHz band and a center 26-tone RU in the 80 MHz band.

In the 80 MHz or 80 + 80/160 MHz HE MU PPDU, the two schemes of the first and second embodiments are mixed to assign a WUR STA to a central 26-tone RU of 20 MHz or 80 MHz, and to transmit the corresponding RU when the HE MU PPDU is transmitted. Is not assigned to the ax STA, the AP may transmit a wakeup frame to the WUR STA.

A WUR STA may be assigned to each 20 MHz centered 26-tone RU and 80 MHz centered 26-tone RU within 80 MHz. A WUR STA with mod (ID, 5) = 0 can be assigned to a primary (or secondary) 20 MHz centered 26-tone RU and a WUR STA with mod (ID, 5) = 1 can be assigned to a secondary (or primary) 20 MHz centered 26 -Ton can be assigned to the RU. A WUR STA with mod (ID, 5) = 2 can be assigned to a 26-tone RU corresponding to a primary (or secondary) 20 MHz centered 26-tone RU at secondary 40 MHz and a WUR STA with mod (ID, 5) = 3 May be assigned to a 26-tone RU corresponding to a secondary (or primary) 20 MHz centered 26-tone RU at secondary 40 MHz. A WUR STA with mod (ID, 5) = 4 may be assigned to an 80 MHz centered 26-tone RU.

A WUR STA may be assigned to each 20 MHz centered 26-tone RU and primary / secondary 80 MHz centered 26-tone RU within 80 + 80/160 MHz. A WUR STA with mod (ID, 10) = 0 can be assigned to a primary (or secondary) 20 MHz centered 26-tone RU and a WUR STA with mod (ID, 10) = 1 can be assigned to a secondary (or primary) 20 MHz centered 26 -Ton can be assigned to the RU. A WUR STA with mod (ID, 10) = 2 may be assigned to a 26-tone RU corresponding to a primary (or secondary) 20 MHz centered 26-tone RU at secondary 40 MHz and a WUR STA with mod (ID, 10) = 3 May be assigned to a 26-tone RU corresponding to a secondary (or primary) 20 MHz centered 26-tone RU at secondary 40 MHz. A WUR STA with mod (ID, 10) = 4 can be assigned to a 26-tone RU corresponding to a primary (or secondary) 20 MHz centered 26-tone RU at secondary 80 MHz and a WUR STA with mod (ID, 10) = 5 May be assigned to a 26-tone RU corresponding to a secondary (or primary) 20 MHz centered 26-tone RU at secondary 80 MHz. A WUR STA with mod (ID, 10) = 6 can be assigned to a 26-tone RU corresponding to a primary (or secondary) 20 MHz centered 26-tone RU of the two central 26-tone RUs corresponding to secondary 40 MHz at 80 MHz secondary. WUR STA with mod (ID, 10) = 7 will be assigned a 26-tone RU corresponding to a secondary (or primary) 20 MHz centered 26-tone RU of the two central 26-tone RUs corresponding to the secondary 40 MHz at the secondary 80 MHz. Can be. WUR STAs with mod (ID, 10) = 8 can be assigned to primary (or secondary) 80MHz centered 26-tone RUs and WUR STAs with mod (ID, 10) = 9 can be assigned to secondary (or primary) 80MHz centered 26 -Ton can be assigned to the RU.

The central 26-ton RU allocated according to the mod results above may vary.

In the situation where the AP transmits 40 MHz, 80 MHz, 80 + 80/160 MHz HE MU PPDU

There may be a case where at least two or more of the center 26-tone RUs and the 80 MHz centered 26-tone RUs within each 20 MHz are not allocated to the ax STA. In this case, the AP may make MU transmissions to the WUR STA using all of the central 26-tone RUs not assigned to the ax STA.

In a fourth embodiment, the wakeup frame may be transmitted using the sequence used for the 11ax OFDMA tone RU.

All available tones of the sequence may be loaded with 1 or -1. Alternatively, a value of 1 or -1 may appear only in two-, four-, and eight-tone tones.

For example, the wakeup frame may be transmitted using the coefficients of the 1x, 2x, and 4x HE-LTF sequences as they are. That is, the coefficients of the 1x, 2x, and 4x HE-LTF sequences may be used as the tone index of the RU used for transmission of the wake-up frame.

An example of the 1x LTF sequence for the 20 MHz band can be determined as follows.

An example of the 1x LTF sequence for the 40 MHz band can be determined as follows.

An example of the 1x LTF sequence for the 80 MHz band can be determined as follows.

An example of a 2x LTF sequence for the 20 MHz band can be determined as follows.

An example of a 2x LTF sequence for the 40 MHz band can be determined as follows.

An example of a 2x LTF sequence for the 80 MHz band can be determined as follows.

An example of a 4x LTF sequence for the 20 MHz band can be determined as follows.

An example of a 4x LTF sequence for the 40 MHz band can be determined as follows.

An example of a 4x LTF sequence for the 80 MHz band can be determined as follows.

However, the above-described LTF sequence is only one embodiment, and various types of LTF sequences for 20 MHz, 40 MHz, and 80 MHz bands may be used.

For another example, the wakeup frame may be transmitted using the coefficients of the 1x and 2x HE-STF sequences as they are. That is, the coefficients of the 1x and 2x HE-STF sequences may be used as the tone index of the RU used for transmission of the wake-up frame.

The HE-STF sequence may be generated by repeating an M sequence which is a binary sequence. The M sequence used basically may be M = {-1, -1, -1, 1, 1, 1, -1, 1, 1, 1, -1, 1, 1, -1, 1}.

In this case, the 1x STF sequence for the 20MHz band can be determined as follows.

In addition, the 1x STF sequence for the 40MHz band can be determined as follows.

In addition, the 1x STF sequence for the 80MHz band can be determined as follows.

In addition, the 2x STF sequence for the 20MHz band can be determined as follows.

In addition, the 2x STF sequence for the 40MHz band can be determined as follows.

In addition, the 2x STF sequence for the 80MHz band can be determined as follows.

However, the above-described STF sequence is only one embodiment, and various types of STF sequences for the 20 MHz, 40 MHz, and 80 MHz bands may be used.

30 may be performed in a network environment in which the first WLAN system and the second WLAN system are supported together. Here, the first WLAN system may correspond to the 802.11ax system, and the second WLAN system may correspond to the 802.11ba system.

An example of FIG. 30 is performed in a transmitter, and a receiver supporting the first WLAN system may correspond to an ax STA, and a receiver supporting the second WLAN system may correspond to a low power wake-up receiver or a WUR STA. have. The transmitter may correspond to the AP.

In step S3010, configure a physical layer protocol data unit (PPDU) to which the first WLAN system is applied.

In operation S3020, the transmitting apparatus transmits a wakeup frame to which the second WLAN system is applied through the PPDU.

If the second frequency band is 20MHz, the LTF sequence may be defined as follows.

If the second frequency band is 40MHz, the LTF sequence may be defined as follows.

If the second frequency band is 80MHz, the LTF sequence may be defined as follows.

That is, the coefficient of the 4x HE-LTF sequence may be used as it is in the tone index of the RU used for transmission of the wake-up frame.

How the wake-up frame is configured is as follows.

The wake-up frame is composed of an on signal and an off signal to which an On-Off Keying (OOK) scheme is applied.

The on signal is transmitted through an on symbol generated by applying a first sequence to 13 consecutive subcarriers in a 20 MHz band and performing a 64-point Inverse Fast Fourier Transform (IFFT). That is, the on signal may correspond to one bit and may be transmitted through one symbol generated by performing an IFFT.

In addition, the transmitter may first configure power values of the on signal and the off signal, and configure the on signal and the off signal. The receiver decodes the on signal and the off signal using an envelope detector, thereby reducing power consumed in decoding.

Referring to FIG. 31, the wireless device may be an AP or a non-AP station (STA) that may implement the above-described embodiment. The wireless device may correspond to the above-described user or may correspond to a transmission device for transmitting a signal to the user.

The AP 3100 includes a processor 3110, a memory 3120, and an RF unit 3130.

The RF unit 1830 may be connected to the processor 3110 to transmit / receive a radio signal.

The processor 3110 may implement the functions, processes, and / or methods proposed herein. For example, the processor 3110 may perform an operation according to the present embodiment described above. That is, the processor 3110 may perform an operation that may be performed by the AP during the operations disclosed in the embodiments of FIGS. 1 to 30.

The non-AP STA 3150 includes a processor 3160, a memory 1870, and a radio frequency unit 3180.

The RF unit 3180 may be connected to the processor 3160 to transmit / receive a radio signal.

The processor 3160 may implement the functions, processes, and / or methods proposed in this embodiment. For example, the processor 3160 may be implemented to perform the non-AP STA operation according to the present embodiment described above. The processor may perform the operation of the non-AP STA in the embodiment of FIGS. 1 to 30.

Processors

3110 and 3160 may include application-specific integrated circuits (ASICs), other chipsets, logic circuits, data processing devices, and / or converters that convert baseband signals and wireless signals to and from each other. The

memories

3120 and 3170 may include read-only memory (ROM), random access memory (RAM), flash memory, memory cards, storage media, and / or other storage devices. The

RF unit

3130 and 3180 may include one or more antennas for transmitting and / or receiving a radio signal.

When the embodiment is implemented in software, the above-described technique may be implemented as a module (process, function, etc.) for performing the above-described function. The module may be stored in the

memories

3120 and 3170 and executed by the

processors

3110 and 3160. The

memories

3120 and 3170 may be inside or outside the

processors

3110 and 3160, and may be connected to the

processors

3110 and 3160 by various well-known means.

Claims

A method of transmitting a wake-up frame in a first wireless LAN system and a second wireless LAN system,

Configuring, by the transmitter, a physical layer protocol data unit (PPDU) to which the first WLAN system is applied; And

The transmitting apparatus, further comprising the step of transmitting a wake-up frame to which the second WLAN system is applied through the PPDU,

The PPDU includes a signal field and a data field,

The data field is transmitted through at least one radio unit (RU) corresponding to the first frequency band indicated by the signal field,

The wakeup frame is transmitted through a center 26-RU located at the center of a second frequency band included in the first frequency band,

The wake-up frame is composed of an on signal and an off signal to which an On-Off Keying (OOK) scheme is applied, and

The on signal is transmitted through an on symbol generated by applying a first sequence to 13 consecutive subcarriers in a 20 MHz band and performing a 64-point Inverse Fast Fourier Transform (IFFT).

Way.
The method of claim 1,

The data field is transmitted to the receiving apparatus supporting the first WLAN system through the at least one RU,

The wake-up frame is transmitted to the receiving apparatus supporting the second WLAN system through the central 26-RU, and

The data field and the wake up frame are transmitted at the same time

Way.
The method of claim 1,

The first frequency band is primary 20 MHz, and the second frequency band is primary 20 MHz, or

The first frequency band is a primary 40 MHz, the second frequency band is each 20 MHz in the primary 40 MHz, or

The first frequency band is a primary 80 MHz, the second frequency band is each 20 MHz in the primary 80 MHz, or

The first frequency band is 80 + 80 MHz or 160 MHz, the second frequency band is each 20 MHz in the 80 + 80 MHz or 160 MHz, and

The central 26-RU of each 20 MHz is allocated based on an identifier (ID) of a receiving device supporting the second WLAN system.

Way.
The method of claim 1,

The first frequency band is 80 + 80 MHz or 160 MHz,

The second frequency band is a primary 80 MHz or a secondary 80 MHz, and

The central 26-RU of the primary 80MHz or the secondary 80MHz is allocated based on the signal field supporting the second WLAN system.

Way.
The method of claim 1,

The first frequency band is 80 MHz,

The second frequency band is each 20 MHz and the 80 MHz in the 80 MHz,

The center 26-RU of each 20 MHz and the center 26-RU of 80 MHz are allocated based on an identifier (ID) of a receiving apparatus supporting the second WLAN system.

Way.
The method of claim 1,

The first frequency band is 80 + 80 MHz or 160 MHz,

The second frequency band is 20 MHz, primary 80 MHz, and secondary 80 MHz in the 80 + 80 MHz or 160 MHz,

The center 26-RU of each 20 MHz, the center 26-RU of the primary 80 MHz, and the center 26-RU of the secondary 80 MHz are allocated based on an identifier (ID) of a receiver supporting the second WLAN system.

Way.
The method of claim 1,

When the wakeup frame is transmitted using a Long Training Field (LTF) sequence for the second frequency band,

If the second frequency band is 20MHz, the LTF sequence is defined as follows,

If the second frequency band is 40MHz, the LTF sequence is defined as follows,

If the second frequency band is 80 MHz, the LTF sequence is defined as follows.

Way.
A transmission apparatus for transmitting a wake-up frame in a first wireless LAN system and a second wireless LAN system,

RF unit for transmitting or receiving a wireless signal; And

A processor for controlling the RF unit, wherein the processor:

Configure a Physical Layer Protocol Data Unit (PPDU) to which the first WLAN system is applied, and

While transmitting the wake-up frame to which the second WLAN system is applied through the PPDU,

The PPDU includes a signal field and a data field,

The data field is transmitted through at least one radio unit (RU) corresponding to the first frequency band indicated by the signal field,

The wakeup frame is transmitted through a center 26-RU located at the center of a second frequency band included in the first frequency band,

The wake-up frame is composed of an on signal and an off signal to which an On-Off Keying (OOK) scheme is applied, and

The on signal is transmitted through an on symbol generated by applying a first sequence to 13 consecutive subcarriers in a 20 MHz band and performing a 64-point Inverse Fast Fourier Transform (IFFT).

Transmitter.