WO2018186648A1 - Procédé et dispositif de transmission de paquet de réveil dans un système rle sans fil - Google Patents

Procédé et dispositif de transmission de paquet de réveil dans un système rle sans fil Download PDF

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Publication number
WO2018186648A1
WO2018186648A1 PCT/KR2018/003895 KR2018003895W WO2018186648A1 WO 2018186648 A1 WO2018186648 A1 WO 2018186648A1 KR 2018003895 W KR2018003895 W KR 2018003895W WO 2018186648 A1 WO2018186648 A1 WO 2018186648A1
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Prior art keywords
signal
information
field
subcarriers
subcarrier
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PCT/KR2018/003895
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English (en)
Korean (ko)
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박은성
임동국
최진수
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엘지전자 주식회사
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/02—Amplitude-modulated carrier systems, e.g. using on-off keying; Single sideband or vestigial sideband modulation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
    • H04W52/02—Power saving arrangements
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
    • Y02D30/00—Reducing energy consumption in communication networks
    • Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks

Definitions

  • 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.
  • 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.
  • IEEE Institute of Electronics and Electronics Engineers
  • PHY physical physical access
  • MAC medium access control
  • next-generation WLAN 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.
  • 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.
  • 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.
  • STA are discussing about improving system performance in a dense environment with many STAs.
  • next-generation WLAN 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.
  • D2D direct-to-direct
  • 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.
  • the first WLAN system may correspond to the 802.11ax system
  • 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.
  • 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.
  • the subcarriers described in this embodiment can be used interchangeably in the same concept as a tone.
  • 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 wake-up frame is composed of an on signal and an off signal to which an On-Off Keying (OOK) scheme is applied.
  • OOK On-Off Keying
  • 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.
  • 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. However, here, the signal field may use a reserved field of HE-SIG-B.
  • the present embodiment proposes a method for transmitting a wake-up frame to multiple users using multiple bands.
  • the multiple bands may be three 26-RUs located at the center of the preset frequency band and a first 52-RU or a second 52-RU located at both ends of the preset frequency band.
  • the first 52-RU corresponds to a 52-RU having a smaller subcarrier index than the three 26-RU
  • the second 52-RU is a subcarrier than the three 26-RU.
  • the larger index can correspond to 52-RU.
  • the signal field may include at least one of three 26-RUs located at the center of a preset frequency band and at least one first 52-RU or a second 52-RU located at both ends of the preset frequency band.
  • the RU indicates that the data frame is to be transmitted. That is, the transmitter may signal to the receiver supporting the first WLAN system that the three 26-RUs and the first 52-RU or the second 52-RU should be emptied through the signal field. This is because the three 26-RUs and the first 52-RU or the second 52-RU must be used to transmit the wakeup frame.
  • the wakeup frame may also be transmitted to multiple users.
  • the wakeup frame may be transmitted to the first receiving device using the three 26-RUs.
  • the first receiving device may support the second WLAN system.
  • the wake-up frame may be transmitted to the first receiving device through a first subcarrier having three subcarrier indices of -26 to 25 in the 26-RU. Coefficients may be inserted into subcarriers other than DC in the first subcarrier.
  • the preset frequency band may be 20 MHz. Accordingly, the DC may be located in a second subcarrier whose subcarrier indices in the three 26-RUs are from -3 to 3. 0 may be inserted into the second subcarrier.
  • the three 26-RUs may be located in a third subcarrier having a subcarrier index of ⁇ 42 to 42.
  • 0 may be inserted into a fourth subcarrier except for a subcarrier whose subcarrier index is from -26 to 25.
  • the fourth subcarrier may be a guard subcarrier.
  • the guard subcarrier may serve to reduce interference from the neighboring RU.
  • the interval between the first and fourth subcarriers may be 78.125 KHz.
  • the first to fourth subcarriers are subcarriers for the PPDU to which the first WLAN system is applied, and a 256-point IFFT may be performed on the PPDU to which the first WLAN system is applied. Different IFFTs may be applied to the PPDU to which the first WLAN system is applied and the wake-up frame to which the second WLAN system is applied. Details will be described later.
  • the coefficient may be inserted only in 13 subcarriers whose subcarrier index is a multiple of 4 in the subcarriers excluding DC in the first subcarrier.
  • the coefficient may be -1 or 1.
  • the coefficient may be inserted using a coefficient of a 1x Long Training Field (LTF) sequence for the preset frequency band.
  • LTF Long Training Field
  • the on signal may be generated by inserting the coefficient into the 13 subcarriers in the 20 MHz band and performing a 64-point Inverse Fast Fourier Transform (IFFT).
  • IFFT Inverse Fast Fourier Transform
  • the spacing of the 13 subcarriers may be 312.5 KHz.
  • the coefficient may be inserted only in seven subcarriers whose subcarrier index is a multiple of 8 in the subcarriers excluding DC in the first subcarrier.
  • the coefficient may be -1 or 1.
  • the coefficient may be inserted by using a coefficient of a 2x short training field (STF) sequence for the preset frequency band.
  • STF short training field
  • M is a preset 15-bit binary sequence, which can be defined as follows.
  • M ⁇ -1, -1, -1, 1, 1, 1, -1, 1, 1, 1, -1, 1, 1, -1, 1 ⁇
  • the on signal may be generated by inserting the coefficient into the seven subcarriers in the 20 MHz band and performing a 64-point IFFT.
  • the wake-up frame may be transmitted to the second receiving apparatus through the first 52-RU or the second 52-RU.
  • the second receiver may support the second WLAN system.
  • both the first 52-RU and the second 52-RU may be used to transmit a wake up frame, or the first 52-RU and the second 52-RU Only one of them may be used to transmit the wakeup frame.
  • a coefficient may be inserted into 13 subcarriers whose subcarrier index is a multiple of 4, and 0 may be inserted into the remaining subcarriers.
  • the coefficient may be -1 or 1.
  • the coefficient may be inserted using coefficients of a 1x LTF sequence for the predetermined frequency band.
  • the 1x LTF sequence for the preset frequency band may be defined as one of the various examples described above.
  • the on signal may be generated by inserting the coefficient into the 13 subcarriers in the 20 MHz band and performing a 64-point IFFT.
  • a coefficient may be inserted into seven subcarriers having a subcarrier index of a multiple of eight, and zero may be inserted into the remaining subcarriers.
  • the coefficient may be -1 or 1.
  • the coefficients may be inserted using coefficients of a 2x STF sequence for the predetermined frequency band.
  • the 2x STF sequence for the preset frequency band may be defined as one of the various examples described above.
  • the on signal may be generated by inserting the coefficients into the seven subcarriers in the 20 MHz band and performing a 64-point IFFT.
  • the signal field may also contain no information in the 26-RU between the three 26-RUs and the first 52-RU or in the 26-RU between the three 26-RUs and the second 52-RU. It may further indicate that it is not transmitted. This is to reduce the interference between the RUs transmitting the wakeup packets.
  • the data field may be transmitted to the receiving device supporting the first WLAN system through the at least one RU.
  • the wakeup frame may be transmitted to a plurality of receiving apparatuses supporting the second WLAN system through the three 26-RUs and the first 52-RU or the second 52-RU. That is, the three 26-RUs and the first 52-RU or the second 52-RU are prevented from being used by the receiver supporting the first WLAN system, thereby receiving the second WLAN system.
  • the device can be used.
  • the data frame and the wake-up frame may be transmitted simultaneously. That is, the data frame and the wake-up frame may be simultaneously transmitted through different frequency bands through an OFDMA technique.
  • 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.
  • 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.
  • WLAN wireless local area network
  • FIG. 2 is a diagram illustrating an example of a PPDU used in the IEEE standard.
  • FIG. 3 is a diagram illustrating an example of a HE PPDU.
  • FIG. 4 is a diagram illustrating an arrangement of resource units (RUs) used on a 20 MHz band.
  • FIG. 5 is a diagram illustrating an arrangement of resource units (RUs) used on a 40 MHz band.
  • FIG. 6 is a diagram illustrating an arrangement of resource units (RUs) used on an 80 MHz band.
  • FIG. 7 is a diagram illustrating another example of the HE-PPDU.
  • FIG. 8 is a block diagram showing an example of the HE-SIG-B according to the present embodiment.
  • FIG. 9 shows an example of a trigger frame.
  • FIG. 10 illustrates an example of subfields included in a per user information field.
  • FIG. 11 is a block diagram showing an example of a control field and a data field constructed according to the present embodiment.
  • 16 illustrates an example in which the control signal and frequency mapping relationship are modified according to the present specification.
  • FIG 17 illustrates an example in which the control signal and frequency mapping relationship are modified according to the present specification.
  • control signal 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.
  • FIG. 21 illustrates a low power wake-up receiver in an environment in which data is not received.
  • FIG. 22 illustrates a low power wake-up receiver in an environment in which data is received.
  • FIG 23 shows an example of a wakeup packet structure 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.
  • FIG. 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.
  • 32 is a block diagram illustrating an example of an apparatus included in a processor.
  • WLAN wireless local area network
  • BSS infrastructure basic service set
  • IEEE Institute of Electrical and Electronic Engineers
  • the WLAN system may include one or more infrastructure BSSs 100 and 105 (hereinafter, BSS).
  • 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.
  • STA STA
  • APs 125 and 130 for providing a distribution service
  • DS distribution system
  • 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.
  • 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).
  • 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).
  • FIG. 1 is a conceptual diagram illustrating an IBSS.
  • 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).
  • MAC medium access control
  • IEEE Institute of Electrical and Electronics Engineers
  • 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.
  • WTRU wireless transmit / receive unit
  • UE user equipment
  • MS mobile station
  • UE mobile subscriber unit
  • It may also be called various names such as a mobile subscriber unit or simply a user.
  • 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.
  • FIG. 2 is a diagram illustrating an example of a PPDU used in the IEEE standard.
  • PPDUs PHY protocol data units
  • LTF and STF fields included training signals
  • SIG-A and SIG-B included control information for the receiving station
  • 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.
  • 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.
  • FIG. 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.
  • a HE-PPDU for a multiple user 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.).
  • FIG. 4 is a diagram illustrating an arrangement of resource units (RUs) used on a 20 MHz band.
  • resource units corresponding to different numbers of tones (ie, subcarriers) may be used to configure some fields of the HE-PPDU.
  • resources may be allocated in units of RUs shown for HE-STF, HE-LTF, and data fields.
  • 26-units ie, units corresponding to 26 tones
  • 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.
  • 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.
  • other bands may be allocated 26-unit, 52-unit, 106-unit. Each unit can be assigned for a receiving station, i. E. A user.
  • 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.
  • FIG. 5 is a diagram illustrating an arrangement of resource units (RUs) used on a 40 MHz band.
  • the example of FIG. 5 may also use 26-RU, 52-RU, 106-RU, 242-RU, 484-RU, and the like.
  • 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.
  • 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.
  • FIG. 6 is a diagram illustrating an arrangement of resource units (RUs) used on an 80 MHz band.
  • the example of FIG. 6 may also use 26-RU, 52-RU, 106-RU, 242-RU, 484-RU, 996-RU, and the like. have.
  • 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.
  • a 996-RU when used for a single user, a 996-RU may be used, in which case five DC tones may be inserted.
  • the specific number of RUs may be changed as in the example of FIGS. 4 and 5.
  • FIG. 7 is a diagram illustrating another example of the HE-PPDU.
  • FIG. 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.
  • AGC automatic gain control
  • 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.
  • 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.
  • 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.
  • PE packet extension
  • 13 a field indicating information on a CRC field of the HE-SIG-A.
  • the HE-SIG-B 740 may be included only when it is a PPDU for a multi-user (MU) as described above.
  • 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.
  • FIG. 8 is a block diagram showing an example of the HE-SIG-B according to the present embodiment.
  • 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.
  • 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.
  • the HE-SIG-B 740 transmitted in a part of the 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.
  • 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.
  • 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.
  • MIMO multiple input multiple output
  • OFDMA orthogonal frequency division multiple access
  • 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.
  • 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.
  • 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
  • the second field may include a field related to a HE system.
  • 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
  • 2048 FFT for a bandwidth of 160 MHz continuous or discontinuous 160 MHz.
  • / IFFT can be applied.
  • 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.
  • 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 ⁇ s, 0.8 ⁇ s, 1.6 ⁇ s, 2.4 ⁇ s, 3.2 ⁇ s.
  • 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.
  • the main band of the first field L-STF, L-LTF, L-SIG, HE-SIG-A, HE-SIG-B
  • HE-STF the main band of the first field
  • HE-LTF, Data the second field
  • 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 may receive the HE-SIG-A 730 and may be instructed to receive the downlink PPDU based on the HE-SIG-A 730.
  • the STA may perform decoding based on the changed FFT size from the field after the HE-STF 750 and the HE-STF 750.
  • the STA may stop decoding and configure a network allocation vector (NAV).
  • NAV network allocation vector
  • 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.
  • 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).
  • downlink data or downlink frame
  • uplink data or uplink frame
  • the transmission from the AP to the STA may be expressed in terms of downlink transmission
  • the transmission from the STA to the AP may be expressed in terms of uplink transmission.
  • 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)).
  • PSDU physical layer service data unit
  • MPDU MAC protocol data unit
  • the PPDU header may include a PHY header and a PHY preamble
  • 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
  • the PHY preamble may be expressed as a PLCP preamble in another term.
  • 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.
  • 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.
  • 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.
  • 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.
  • the AP may perform DL MU transmission based on OFDMA, and such transmission may be expressed by the term DL MU OFDMA transmission.
  • 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.
  • UL MU transmission uplink multi-user transmission
  • 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.
  • 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.
  • each of a plurality of STAs 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • OBSS overlapped BSS
  • 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.
  • a WLAN system supporting the OFDMA technology supporting the OFDMA technology. That is, the above-described OFDMA technique is applicable to at least one of downlink and uplink.
  • the above-described MU-MIMO technique may be additionally applied to at least one of downlink and uplink.
  • 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.
  • the AP 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).
  • OFDMA orthogonal frequency division multiple access
  • Different frequency resources for each of the plurality of STAs are indicated through 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.
  • 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.
  • 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.
  • 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”.
  • 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.
  • FIG. 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • the first control field may be the HE-SIG-A 730 illustrated in FIG. 7
  • the second control field may be the HE-SIG-B 740 illustrated in FIGS. 7 and 8. Can be.
  • 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 may indicate whether 242-RU is allocated, for example when 20 MHz transmission is performed.
  • 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.
  • 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 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.
  • 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.
  • the control identifier eg, 1-bit identifier
  • the control 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.
  • control identifier eg, 1 bit identifier
  • MU-MIMO multi-user full bandwidth MU-MIMO
  • MIMO 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.
  • the control identifier eg, 1 bit identifier
  • FIG. 11 is a block diagram showing an example of a control field and a data field constructed according to the present embodiment.
  • 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.
  • 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.
  • the bandwidth of the transmission frequency band is not limited and may be applied to a 40 MHz, 80 MHz, and 160 MHz transmission.
  • the above-described control identifier may be included in the first and / or second control field.
  • the control identifier 1110 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.
  • 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.
  • 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.
  • a control identifier eg, a 1-bit identifier
  • 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.
  • 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.
  • the above-described control identifier (eg, 1 bit identifier) may be omitted since 242-RU is allocated as a single user (SU) transmission.
  • 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.
  • the left block of FIG. 12 indicates information corresponding to the first and / or second control field.
  • the left block of FIG. 12 corresponds to the second control field (ie, SIG-B)
  • the right block of FIG. 12 corresponds to the data field of the PPDU.
  • each control field and data field correspond to a 20 MHz band.
  • control identifier eg, 1-bit identifier
  • allocation information for the RU may be omitted.
  • a control identifier eg, 1 bit identifier
  • 242-RU or 242-type RU
  • control identifier is included in the front of the common field of the SIG-B.
  • 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.
  • 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.
  • control identifier eg, 1-bit identifier
  • 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.
  • 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.
  • 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.
  • SIG-B second control field
  • the second control field (ie, SIG-B) may be configured separately for each 20MHz channel.
  • SIG-B the second control field
  • the present specification proposes an example of independently configuring the lower two 20 MHz channels 1330 and the upper two 20 MHz channels 1340.
  • SIG-B 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.
  • SIG-B is preferably configured according to the above-described replication method.
  • 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.
  • SIG-B corresponding to the second channel first displays AID3 corresponding to STA3, and then displays AID corresponding to STA4.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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 ⁇ .
  • the second identifier 1550 corresponding to the first channel indicates "1"
  • 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.
  • 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.
  • FIG. 15 Other features of the example of FIG. 15 are the same as those of FIGS. 13 to 14.
  • 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.
  • 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 ⁇ .
  • 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.
  • 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.
  • FIG. 16 Other features of the example of FIG. 16 are the same as those of FIGS. 13 to 15.
  • a first identifier 1710 is included in front of a SIG-B field corresponding to each 20 MHz, followed by a second identifier 1720.
  • 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 ⁇ .
  • the second identifier 1750 corresponding to the first channel indicates “1”
  • 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.
  • FIG. 17 Other features of the example of FIG. 17 are the same as those of FIGS. 13 to 16.
  • 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.
  • 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 ⁇ .
  • the second identifier 1850 corresponding to the first channel indicates “1”
  • 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.
  • FIG. 18 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.
  • 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
  • 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.
  • the first control field 1910 may include control information for interpretation of the PPDU 1901.
  • 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).
  • the control identifier (eg, the first identifier and / or the second identifier) described with reference to FIGS. 11 to 18 may be included.
  • 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.
  • the control identifier eg, 1-bit identifier
  • the 1-bit identifier has a technical effect that can be signaled for full-band multi-user full-width MU-MIMO (MIMO).
  • 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.
  • 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.
  • the second control field generally includes allocation information for a resource unit (RU) through the common field 1920.
  • the control identifier eg, 1 bit identifier
  • allocation information for the RU is preferably omitted. That is, the common field 1920 may be omitted.
  • the common field 1920 can be omitted because it is not necessary to configure allocation information for the RU separately.
  • the control identifier eg, 1-bit identifier
  • the common field 1920 of the second control field is used for a resource unit (RU).
  • 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.
  • the second control field and the data field 1940 may have a mapping relationship as shown in FIGS. 13 to 18.
  • 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.
  • 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.
  • part of the second control field may be duplicated in the PPDU 1901. Replication for the second control field may be variously implemented.
  • first, second, third, and fourth signal fields 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • identification information e.g, AID
  • 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.
  • 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.
  • the second control fields 1921 and 1931 correspond to two data fields 1941 and 1943 corresponding to the first and third frequency bands.
  • 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.
  • SIG-B includes a common field 2010 and a user specific field 2020.
  • 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.
  • the four SIG-B fields may be called various names such as first to fourth signal fields.
  • 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.
  • 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.
  • 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,
  • 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.
  • the SIG-B corresponding to the first and third frequency bands is preferably replicated on the second and fourth frequency bands.
  • 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).
  • the RU lookup table may be configured through 5-bit information.
  • 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.
  • the signal related to the MU-MIMO technique can be embodied as follows.
  • a 3-bit or 4-bit MU-MIMO indicator ie, MU-MIMO field
  • MU-MIMO field a 3-bit or 4-bit MU-MIMO indicator
  • 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.
  • the MU-MIMO indicator (ie, MU-MIMO field) may be specified as follows.
  • a user STA multiplexed on each 106-RU by 2 bits may be indicated.
  • a combination of the number of users that can be multiplexed into each 106-RU may be limited.
  • 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.
  • 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.
  • 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.
  • 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.
  • FFTs Fast Fourier Tranforms
  • CP portion cyclic prefix portion
  • the length of the effective symbol interval (or FFT interval) may be 3.2us
  • the CP length is 0.8us
  • 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 802.11 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).
  • OFDMA Orthogonal Frequency Division Multiple Access
  • 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.
  • LP-WUR low-power wake-up receiver
  • 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.
  • low power wake-up receivers use a narrow bandwidth of less than 5 MHz.
  • 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.
  • 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.
  • LP-WUR low power wake-up receiver
  • the Wi-Fi / BT / BLE 2120 is turned off and the low power wake-up receiver 2130 is turned on without receiving data.
  • LP-WUR low power wake-up receiver
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • the transmitter 2200 may be set to transmit a wakeup packet to the receiver 2210.
  • the low power wake-up receiver 2230 may be instructed to wake up the main radio 2220.
  • FIG 23 shows an example of a wakeup packet structure according to the present embodiment.
  • the wakeup packet may include one or more legacy preambles.
  • One or more legacy devices may decode or process the legacy preamble.
  • 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.
  • OOK On-Off Keying
  • 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.
  • the wakeup packet 2300 may include a legacy preamble or any other preamble 2310 defined by the IEEE 802.11 specification.
  • 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.
  • 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.
  • 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.
  • the payload 2320 may include a frame body 2326 that may include other information of the wakeup packet.
  • the frame body 2326 may include length or size information of the payload.
  • the payload 2320 may include a Frame Check Sequence (FCS) field 2328 including a Cyclic Redundancy Check (CRC) value.
  • FCS Frame Check Sequence
  • CRC Cyclic Redundancy Check
  • it may include a CRC-8 value or a CRC-16 value of the MAC header 2324 and the frame body 2326.
  • 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.
  • 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.
  • the payload may be modulated according to the OOK method.
  • the wakeup preamble 2422 in the payload may be modulated according to another modulation scheme.
  • 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.
  • 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.
  • 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.
  • 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.
  • the receiver receives and restores data transmitted in the form of visible light, thereby enabling communication using visible light.
  • the blinking of the light emitting diode cannot be perceived by the human eye, the person feels that the illumination is continuously maintained.
  • FIG. 25 information of a binary sequence form having 10 bit values is used.
  • FIG. 25 there is information in the form of a binary sequence having a value of '1001101011'.
  • 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.
  • the power consumption of the transmitter is determined according to the ratio of 1 and 0 constituting the binary sequence information.
  • the ratio of 1 and 0 which constitutes information in binary sequence form, must also be maintained.
  • the ratio of 1 and 0 constituting the information in the form of a binary sequence must also be maintained.
  • the receiver is mainly a wake-up receiver (WUR)
  • WUR wake-up receiver
  • 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.
  • power consumption of Resonator + Oscillator + PLL (1500uW)-> LPF (300uW)-> ADC (63uW)-> decoding processing (OFDM receiver) (100mW) may occur.
  • -WUR power consumption is about 1mW.
  • 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.
  • the OOK method is applied to the ON-signal.
  • the on signal is a signal having an actual power value
  • the 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.
  • information (bit) 1 may be an on signal and information (bit) 0 may be an off signal.
  • information 1 may indicate a transition from an off signal to an on signal
  • information 0 may indicate a transition from an on signal to an off signal.
  • the information 1 may indicate the transition from the on signal to the off signal
  • the information 0 may indicate the transition from the off signal to the on signal. Manchester coding scheme will be described later.
  • a transmitter applies a sequence by selecting 13 consecutive subcarriers of a 20 MHz band as a reference band as a sample.
  • 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.
  • the subcarrier index 0 may be nulled to 0 as the DC subcarrier.
  • 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.
  • SNR signal to noise ratio
  • the power consumption of the AC / DC converter of the receiver can be reduced.
  • the power consumption can be reduced by reducing the sampling frequency band to 4.06MHz.
  • 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.
  • the transmitter may not transmit the off signal at all.
  • 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.
  • the basic data rate for one information may be 125 Kbps (8us) or 62.5Kbps (16us).
  • 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.
  • the indices of the K subcarriers used by the signal corresponding to the information 0 and the information 1 are the same.
  • the subcarrier index used may be represented as 33-floor (K / 2): 33 + ceil (K / 2) -1.
  • the information 1 and the information 0 may have the following values.
  • the alpha is a power normalization factor and may be, for example, 1 / sqrt (K).
  • 27 is an explanatory diagram for Manchester coding technique according to the present embodiment.
  • 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.
  • 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.
  • bit string to be transmitted 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.
  • 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.
  • the symbol 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.
  • the bit string to be transmitted is 10011101
  • the Manchester coded signal is 0110100101011001
  • 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.
  • 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.
  • a symbol coding based symbol coding technique and a symbol repetition technique may be used.
  • a symbol reduction technique may be used to obtain a high data rate.
  • each symbol may be generated using an existing 802.11 OFDM transmitter.
  • the number of subcarriers used to generate each symbol may be thirteen. However, it is not limited thereto.
  • 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.
  • CP Cyclic Prefix or Guard Interval
  • 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.
  • 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.
  • a coefficient of 0 may be loaded on the DC subcarrier or the middle subcarrier index among all available subcarriers.
  • 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.
  • one bit information corresponding to one basic WUR symbol may be represented as shown in the following table.
  • 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.
  • 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.
  • the time used for transmitting one bit (or symbol) except for the guard interval of the transmission signal is 3.2 us.
  • 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.
  • 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)).
  • 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.
  • 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.
  • a, b, c, d, e, f, g is 1 or -1.
  • 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.
  • 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.
  • the sub information 0 may have a value of zeros (1, K).
  • 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 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.
  • 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.
  • 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.
  • one bit information corresponding to one Manchester coded symbol may be represented as shown in the following table.
  • 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.
  • 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.
  • CP cyclic prefix
  • Option 1 Information 0 and Information 1 can be repeatedly represented by the same symbol.
  • Option 2 Information 0 and Information 1 can be repeatedly represented by different symbols.
  • 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.
  • non-coherent detection the phase relationship between the transmitter and receiver signals is not fixed.
  • the receiver does not need to measure and adjust the phase of the received signal.
  • 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.
  • 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.
  • 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.
  • information may be determined by comparing the power of two symbols without determining a threshold.
  • 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.
  • the interleaver may be applied in units of specific symbol numbers below the packet unit.
  • n can be extended as follows. 28 illustrates various examples of a symbol repetition technique of repeating n symbols according to the present embodiment.
  • information 0 and information 1 may be repeatedly represented by the same symbol n times.
  • the information 0 and the information 1 may be repeatedly displayed n times with different symbols.
  • 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.
  • 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).
  • the interleaver may be applied in units of packets and specific symbols.
  • 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.
  • consecutive symbol 0 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.
  • the option 2 scheme may be preferred as it is desirable to avoid the use of consecutive off symbols to solve the leveling problem.
  • 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.
  • a code rate of 3/4 may be 1,010 or 010,1 or 0,010 or 010,0.
  • a code rate of 1/2 it may be desirable to apply a code rate of 1/2 or less.
  • the order of symbols can be reconstructed by the interleaver.
  • the interleaver may be applied in units of packets and specific symbols.
  • a symbol to which the symbol repetition technique is applied may be represented by n (CP + 3.2us) or CP + n (1.6us).
  • 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.
  • 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.
  • 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.
  • 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.
  • two information signals 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.
  • 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.
  • one bit information corresponding to a symbol to which the symbol repetition technique is applied may be represented as shown in the following table.
  • 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. .
  • 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.
  • three information signals 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.
  • 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.
  • one bit information corresponding to a symbol to which the symbol repetition technique is applied may be represented as shown in the following table.
  • 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 + 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.
  • 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.
  • 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.
  • one bit information corresponding to a symbol to which the symbol repetition technique is applied may be represented as shown in the following table.
  • Table 7 does not indicate CP separately. Indeed, CP + 3.2us + 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 + 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.
  • 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).
  • 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.
  • 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.
  • 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.
  • 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.
  • the symbol repetition technique can satisfy the range requirement of low power wake-up communication.
  • the data rate for one symbol is 250 Kbps (4us).
  • the data rate may be 125 Kbps (8us)
  • the fourth repetition is performed, the data rate may be 62.5 Kbps (16us)
  • the eight times are repeated, the data rate may be 31.25Kbps (32us).
  • the symbol needs to be repeated eight times to satisfy the range requirement.
  • the symbol is further reduced to reduce the length of the symbol carrying one piece of information.
  • 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.
  • 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).
  • the on signal may be configured as follows.
  • the on signal may be configured as follows.
  • the on signal may be configured as follows.
  • the 3.2us / m information signal is divided into a 3.2us / m on signal and a 3.2us / m off signal.
  • 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.
  • 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.
  • 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.
  • the time used for transmitting one bit (or symbol) except for the guard interval of the transmission signal is 3.2 us.
  • the time used for one bit transmission is 3.2us / m.
  • 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.
  • information 0 may be configured as 01 and information 1 may be configured as 10.
  • 1-bit information corresponding to a symbol to which a symbol reduction technique is applied may be represented as shown in the following table.
  • CP is not separately indicated.
  • 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.
  • Option 1 2,4,8) 2us OFF-signal 2us ON-signal 1us OFF-signal 1us ON-signal 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.
  • 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.
  • 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.
  • CP Default symbol (Example 1) (CP + 3.2us) Man. Symbol (Example 2) (CP + 1.6 + CP + 1.6) Man. Symbol (Example 3) (CP + 1.6 + 1.6) 0.4us 277.8 250.0 277.8 0.8us 250.0 208.3 250.0
  • 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. More specifically, the present invention proposes a method of transmitting WUR frames simultaneously with 11ax data frame transmission using three central 26-tone RUs or 52-tone RUs of an 802.11ax system in an IEEE 802.11ba system.
  • Wake-up frames can be sent using narrow bands for power consumption or performance gain.
  • 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.
  • 40 entries are reserved, and additional signaling may be considered for a case where a WUR packet is carried using the same. That is, the RU carrying the WUR packet can be signaled to an ax STA in an empty state, and a bit index for the signaling is proposed. In this case, the RU carrying the WUR packet may be proposed to be 52 tone RUs corresponding to 4 MHz bands in each 20 MHz or three 26 tone RUs in the center.
  • 4 is an OFDMA tone plan at 20 MHz, with a total of four 52 tone RUs in each 20 MHz subband in an 11ax OFDMA tone plan, and the WUR packet with data from ax STA over 11ax HE MU PPDU using each 52 tone RU. Can be sent.
  • the data for the ax STA except for the 52 tone RU on which the WUR packet is carried may be transmitted on 26, 52, and 106 tone RUs. Since four 52 tone RUs may be used, if a WUR packet for one WUR STA is transmitted to each RU, the WUR packet may be transmitted to one to four WUR STAs on a 20 MHz subband basis.
  • the indicators in these various cases can be signaled using the reserved fields of HE-SIG B of Tables 16 and 17 below and will be shown in a later embodiment.
  • a 52 tone RU carrying a WUR packet may carry a coefficient of 1 or -1, or a coefficient of 1 or -1 is only included in an index such as a multiple of 2, a multiple of 4, or a multiple of 8 in the 52 tone RU and the remaining tones A coefficient of zero can be carried.
  • 1x, 2x, 4x HE-LTF or 1x, 2x HE-STF coefficients of the same index may be inserted.
  • WUR packets are transmitted to four 52-tone RUs in 20 MHz subbands, interference may be severe because each is too close. Therefore, one to three persons using two 52-tone RUs at the edge and three 26-tone RUs at the center at each 20MHz (one WUR packet can be considered using three 26-tone RUs) can be considered.
  • a WUR packet can be transmitted to a WUR STA up to (the transmitter can transmit a WUR packet to multiple users using multiple bands). In this case, a 26 tone RU is located between the three central 26 tone RUs and the 52 tone RUs at both ends. Data may be transmitted to an ax STA using a 26 tone RU located in between, or no information may be transmitted to reduce interference of a WUR packet.
  • a WUR packet is sent to one WUR STA, it may be assumed that three central 26 tone RUs are used, and an embodiment of signaling will be described later.
  • tone index and coefficient in the situation according to each bandwidth when three central 26 tone RU is used. That is, a tone plan for transmitting ON-signal in three central 26 tone RUs for WUR packets (or WUR data) is proposed. A tone plan for transmitting ON-signal in three central 26 tone RUs is described with reference to FIGS. 4 to 6 showing the arrangement of RUs used on the 20 MHz / 40 MHz / 80 MHz band.
  • the tone indexes of the center three 26 tone RUs at 20 MHz are ⁇ 42 to 42 including DC.
  • the tone index can use -26 to 25 or -25 to 26.
  • the DC may be -3 to 3 (or -1 to 1), and a coefficient of 1 or -1 may be inserted into the 4 MHz tone except for this, and a coefficient of 0 may be inserted into the remaining tones of the three 26 tone RUs. .
  • a coefficient of 1 or -1 may be inserted only in tones having a tone index of multiples of two, multiples of four or multiples of eight (two, four, or eight squares) excluding DC in the 4 MHz band. Coefficients of zero may be inserted into tones in three other 26 tone RUs.
  • coefficients in the 4 MHz band may be inserted with coefficients of 1x, 2x, 4x HE-LTF or 1x, 2x HE-STF of the same tone index, and zero coefficients may be inserted into tones within three other 26 tone RUs.
  • It is possible to play the role of a guard tone by inserting a coefficient of 0 in a tone having a -42 to -27 and a 26 to 42 tone index.
  • the guard tone may play a role of reducing interference from the surrounding tone RU.
  • the tone indexes of the center three 26 tone RUs of each 20 MHz subband of 40 MHz are -163 to -84 and the right 20 MHz subbands of 84 to 163 including null subcarriers.
  • the tone index can use -149 to -98 for the left 20MHz subband and 98 to 149 for the right 20MHz subband.
  • the null subcarrier is -137, -110 for the left 20 MHz subband and 110, 137 for the right 20 MHz subband, and a coefficient of 1 or -1 is inserted into the 4 MHz tone except for this and 0 for the remaining tones of the three 26 tone RUs. It can be configured by inserting coefficients.
  • a coefficient of 1 or -1 can be inserted in the null subcarrier.
  • coefficients in the 4MHz band may be inserted with coefficients of 1x, 2x, 4x HE-LTF or 1x, 2x HE-STF of the same tone index, and zero coefficients may be inserted into tones within three other 26 tone RUs.
  • a guard tone can be performed by inserting a coefficient of 0 into -163 to -150 and -97 to -84 of the left 20 MHz subband, and 84 to 97 and 150 to 163 tone indices of the right 20 MHz subband.
  • the guard tone may play a role of reducing interference from the surrounding tone RU.
  • the tone indexes of the center three 26 tone RUs of each 20 MHz subband of 80 MHz include null subcarriers, the first 20 MHz subbands are -419 to -340, and the second 20 MHz subbands are -177 to -98, and the third.
  • the 20 MHz subbands are 98-177 and the fourth 20 MHz subbands are 340-419.
  • 4 MHz can often be considered, where the tone index is -405 to -354 for the first 20 MHz subband, -163 to -112 for the second 20 MHz subband, and 112 to 163 for the third 20 MHz subband.
  • the first 20 MHz subband may use 354 to 405.
  • the null subcarrier is -393, -366 for the first 20 MHz subband, -151, -124 for the second 20 MHz subband, 124, 151 for the third 20 MHz subband, and 366, 393 for the fourth 20 MHz subband.
  • a coefficient of 1 or -1 may be inserted into the 4 MHz tone except for this, and a coefficient of 0 may be inserted into the remaining tones of the three 26 tone RUs.
  • a coefficient of 1 or -1 can be inserted in the null subcarrier.
  • coefficients in the 4 MHz band may be inserted with coefficients of 1x, 2x, 4x HE-LTF or 1x, 2x HE-STF of the same tone index, and zero coefficients may be inserted into tones within three other 26 tone RUs. . -419 to -406 and -353 to -340 for the first 20 MHz subband, -177 to -164 and -111 to -98 for the second 20 MHz subband, 98 to 111 and 164 to 177 for the third 20 MHz subband, It can act as a guard tone by inserting a coefficient of zero in the 340-353 and 406-419 tone indexes of the fourth 20 MHz subband.
  • the guard tone may play a role of reducing interference from the surrounding tone RU.
  • a 52 tone RU carrying a WUR packet may have a coefficient of 1 or -1, or a coefficient of 1 or -1 is included only in an index such as a multiple of 2, a multiple of 4, and a multiple of 8 in the 52 tone RU.
  • Tones may carry a coefficient of zero.
  • 1x, 2x, 4x HE-LTF or 1x, 2x HE-STF coefficients of the same index may be inserted.
  • coefficients of 1x, 2x, 4x HE-LTF or 1x, 2x HE-STF of the same tone index may be inserted into the tones of the 4MHz band where the wake-up packet is transmitted.
  • 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 wakeup packet.
  • 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.
  • LTF sequence is only one embodiment, and various types of LTF sequences for 20 MHz, 40 MHz, and 80 MHz bands may be used.
  • 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 1x STF sequence for the 20MHz band can be determined as follows.
  • the 1x STF sequence for the 40MHz band can be determined as follows.
  • the 1x STF sequence for the 80MHz band can be determined as follows.
  • the 2x STF sequence for the 20MHz band can be determined as follows.
  • the 2x STF sequence for the 40MHz band can be determined as follows.
  • the 2x STF sequence for the 80MHz band can be determined as follows.
  • 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.
  • bit index can be signaled using the following secured bits.
  • a WUR packet When a WUR packet is transmitted using 52 tone RU in each 20MHz subband, there are 14 cases from 1 to 4 persons, and data of ax STA can also be transmitted simply using 52 tone RU.
  • the 26 tone RU around the 52 tone RU in which the WUR packet is transmitted may not be used for data transmission of the ax STA to reduce interference.
  • a central 26 tone RU may or may not be used.
  • each 20 MHz subband when one to three WUR packets are transmitted using two 52-tone RUs and three 26-tone RUs in each center, there may be four cases under the assumption that three 26-tone RUs in the center are necessarily used. .
  • data may be transmitted to the ax STA using 26 tone RU and 52 tone RU, and the 26 tone RU around the RU in which the WUR packet is transmitted may not be used for any transmission.
  • the RU used to transmit the WUR packet is indicated by an empty state because it is indicated as being empty.
  • an RU not used for transmission of the WUR packet and not used for data transmission for the ax STA is denoted by X.
  • Signaling may also be performed using the reserved fields of HE-SIG B of Table 18 below.
  • signaling may be performed using the reserved fields shown in Table 21 below.
  • the preceding four tone plans of Table 23 may indicate an RU carrying 11ax data using 011101x 1 ⁇ 0 of Table 21.
  • the following four tone plans of Table 23 may indicate an RU carrying 11ax data using 01111y 2 y 1 y 0 of Table 21.
  • y 2 may be fixed to 1. 01111y 2
  • a WUR packet is transmitted using three central 26 tone RUs and / or 52 tone RUs, and a WUR packet is transmitted.
  • the 26 tone RU around the RU may not be used for any transmission.
  • the 52 tone RU used for data transmission of the ax STA may be divided into two 26 tone RUs and used for data transmission of the ax STA, and two 52 tone RUs attached to each other may be combined to transmit data of the ax STA to the 106 tone RU. May be used.
  • the above-described bit index is only one example, and the order thereof may be changed, and the bit index may be set by a combination of different embodiments.
  • FIG. 30 is a flowchart illustrating a procedure of transmitting a wake-up frame using the HE-PPDU according to the present embodiment.
  • the first WLAN system may correspond to the 802.11ax system
  • the second WLAN system may correspond to the 802.11ba system.
  • FIG. 30 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.
  • 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.
  • the subcarriers described in this embodiment can be used interchangeably in the same concept as a tone.
  • step S3010 configure a physical layer protocol data unit (PPDU) to which the first WLAN system is applied.
  • PPDU physical layer protocol data unit
  • the transmitting apparatus transmits a wakeup frame to which the second WLAN system is applied through the PPDU.
  • the wake-up frame is composed of an on signal and an off signal to which an On-Off Keying (OOK) scheme is applied.
  • OOK On-Off Keying
  • 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. However, here, the signal field may use a reserved field of HE-SIG-B.
  • the present embodiment proposes a method for transmitting a wake-up frame to multiple users using multiple bands.
  • the multiple bands may be three 26-RUs located at the center of the preset frequency band and a first 52-RU or a second 52-RU located at both ends of the preset frequency band.
  • the first 52-RU corresponds to a 52-RU having a smaller subcarrier index than the three 26-RU
  • the second 52-RU is a subcarrier than the three 26-RU.
  • the larger index can correspond to 52-RU.
  • the signal field may include at least one of three 26-RUs located at the center of a preset frequency band and at least one first 52-RU or a second 52-RU located at both ends of the preset frequency band.
  • the RU indicates that the data frame is to be transmitted. That is, the transmitter may signal to the receiver supporting the first WLAN system that the three 26-RUs and the first 52-RU or the second 52-RU should be emptied through the signal field. This is because the three 26-RUs and the first 52-RU or the second 52-RU must be used to transmit the wakeup frame.
  • the wakeup frame may also be transmitted to multiple users.
  • the wakeup frame may be transmitted to the first receiving device using the three 26-RUs.
  • the first receiving device may support the second WLAN system.
  • the wake-up frame may be transmitted to the first receiving device through a first subcarrier having three subcarrier indices of -26 to 25 in the 26-RU. Coefficients may be inserted into subcarriers other than DC in the first subcarrier.
  • the preset frequency band may be 20 MHz. Accordingly, the DC may be located in a second subcarrier whose subcarrier indices in the three 26-RUs are from -3 to 3. 0 may be inserted into the second subcarrier.
  • the three 26-RUs may be located in a third subcarrier having a subcarrier index of ⁇ 42 to 42.
  • 0 may be inserted into a fourth subcarrier except for a subcarrier whose subcarrier index is from -26 to 25.
  • the fourth subcarrier may be a guard subcarrier.
  • the guard subcarrier may serve to reduce interference from the neighboring RU.
  • the interval between the first and fourth subcarriers may be 78.125 KHz.
  • the first to fourth subcarriers are subcarriers for the PPDU to which the first WLAN system is applied, and a 256-point IFFT may be performed on the PPDU to which the first WLAN system is applied. Different IFFTs may be applied to the PPDU to which the first WLAN system is applied and the wake-up frame to which the second WLAN system is applied. Details will be described later.
  • the coefficient may be inserted only in 13 subcarriers whose subcarrier index is a multiple of 4 in the subcarriers excluding DC in the first subcarrier.
  • the coefficient may be -1 or 1.
  • the coefficient may be inserted using a coefficient of a 1x Long Training Field (LTF) sequence for the preset frequency band.
  • LTF Long Training Field
  • the 1x LTF sequence for the preset frequency band may be defined as follows.
  • the on signal may be generated by inserting the coefficient into the 13 subcarriers in the 20 MHz band and performing a 64-point Inverse Fast Fourier Transform (IFFT).
  • IFFT Inverse Fast Fourier Transform
  • the spacing of the 13 subcarriers may be 312.5 KHz.
  • the coefficient may be inserted only in seven subcarriers whose subcarrier index is a multiple of 8 in the subcarriers excluding DC in the first subcarrier.
  • the coefficient may be -1 or 1.
  • the coefficient may be inserted by using a coefficient of a 2x short training field (STF) sequence for the preset frequency band.
  • STF short training field
  • the 2x STF sequence for the preset frequency band may be defined as follows.
  • M is a preset 15-bit binary sequence, which can be defined as follows.
  • M ⁇ -1, -1, -1, 1, 1, 1, -1, 1, 1, 1, -1, 1, 1, -1, 1 ⁇
  • the on signal may be generated by inserting the coefficient into the seven subcarriers in the 20 MHz band and performing a 64-point IFFT.
  • the wake-up frame may be transmitted to the second receiving apparatus through the first 52-RU or the second 52-RU.
  • the second receiver may support the second WLAN system.
  • both the first 52-RU and the second 52-RU may be used to transmit a wake up frame, or the first 52-RU and the second 52-RU Only one of them may be used to transmit the wakeup frame.
  • a coefficient may be inserted into 13 subcarriers whose subcarrier index is a multiple of 4, and 0 may be inserted into the remaining subcarriers.
  • the coefficient may be -1 or 1.
  • the coefficient may be inserted using coefficients of a 1x LTF sequence for the predetermined frequency band.
  • the 1x LTF sequence for the preset frequency band may be defined as one of the various examples described above.
  • the on signal may be generated by inserting the coefficient into the 13 subcarriers in the 20 MHz band and performing a 64-point IFFT.
  • a coefficient may be inserted into seven subcarriers having a subcarrier index of a multiple of eight, and zero may be inserted into the remaining subcarriers.
  • the coefficient may be -1 or 1.
  • the coefficients may be inserted using coefficients of a 2x STF sequence for the predetermined frequency band.
  • the 2x STF sequence for the preset frequency band may be defined as one of the various examples described above.
  • the on signal may be generated by inserting the coefficients into the seven subcarriers in the 20 MHz band and performing a 64-point IFFT.
  • the signal field may also contain no information in the 26-RU between the three 26-RUs and the first 52-RU or in the 26-RU between the three 26-RUs and the second 52-RU. It may further indicate that it is not transmitted. This is to reduce the interference between the RUs transmitting the wakeup packets.
  • the data field may be transmitted to the receiving device supporting the first WLAN system through the at least one RU.
  • the wakeup frame may be transmitted to a plurality of receiving apparatuses supporting the second WLAN system through the three 26-RUs and the first 52-RU or the second 52-RU. That is, the three 26-RUs and the first 52-RU or the second 52-RU are prevented from being used by the receiver supporting the first WLAN system, thereby receiving the second WLAN system.
  • the device can be used.
  • the data frame and the wake-up frame may be transmitted simultaneously. That is, the data frame and the wake-up frame may be simultaneously transmitted through different frequency bands through an OFDMA technique.
  • 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.
  • 31 is a block diagram illustrating a wireless device to which the present embodiment can be applied.
  • a wireless device may be an STA or an non-AP STA as an STA capable of implementing 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 wireless device of FIG. 31 includes a processor 3110, a memory 3120, and a transceiver 3130 as shown.
  • the processor 3110, the memory 3120, and the transceiver 3130 may be implemented as separate chips, or at least two blocks / functions may be implemented through one chip.
  • the transceiver 3130 is a device including a transmitter and a receiver. When a specific operation is performed, only one of the transmitter and the receiver is performed, or both the transmitter and the receiver are performed. Can be.
  • the transceiver 3130 may include one or more antennas for transmitting and / or receiving wireless signals.
  • the transceiver 3130 may include an amplifier for amplifying the reception signal and / or the transmission signal and a bandpass filter for transmission on a specific frequency band.
  • the processor 3110 may implement the functions, processes, and / or methods proposed herein.
  • the processor 3110 may perform an operation according to the present embodiment described above. That is, the processor 3110 may perform the operations disclosed in the embodiments of FIGS. 1 to 30.
  • the processor 3110 may include an application-specific integrated circuit (ASIC), another chipset, a logic circuit, a data processing device, and / or a converter for translating baseband signals and wireless signals.
  • the memory 3120 may include read-only memory (ROM), random access memory (RAM), flash memory, memory card, storage medium, and / or other storage device.
  • FIG. 32 is a block diagram illustrating an example of an apparatus included in a processor. For convenience of description, an example of FIG. 32 is described based on a block for a transmission signal, but it is obvious that the reception signal can be processed using the block.
  • the illustrated data processor 3210 generates transmission data (control data and / or user data) corresponding to the transmission signal.
  • the output of the data processor 3210 may be input to the encoder 3220.
  • the encoder 3220 may perform coding through a binary convolutional code (BCC) or a low-density parity-check (LDPC) technique. At least one encoder 3220 may be included, and the number of encoders 3220 may be determined according to various information (eg, the number of data streams).
  • BCC binary convolutional code
  • LDPC low-density parity-check
  • the output of the encoder 3220 may be input to the interleaver 3230.
  • the interleaver 3230 performs an operation of distributing consecutive bit signals over radio resources (eg, time and / or frequency) to prevent burst errors due to fading or the like.
  • Radio resources eg, time and / or frequency
  • At least one interleaver 3230 may be included, and the number of the interleaver 3230 may be determined according to various information (eg, the number of spatial streams).
  • the output of the interleaver 3230 may be input to a constellation mapper 3240.
  • the constellation mapper 3240 performs constellation mapping such as biphase shift keying (BPSK), quadrature phase shift keying (QPSK), and quadrature amplitude modulation (n-QAM).
  • BPSK biphase shift keying
  • QPSK quadrature phase shift keying
  • n-QAM quadrature amplitude modulation
  • the output of the constellation mapper 3240 may be input to the spatial stream encoder 3250.
  • the spatial stream encoder 3250 performs data processing to transmit a transmission signal through at least one spatial stream.
  • the spatial stream encoder 3250 may perform at least one of space-time block coding (STBC), cyclic shift diversity (CSD) insertion, and spatial mapping on a transmission signal.
  • STBC space-time block coding
  • CSS cyclic shift diversity
  • the output of the spatial stream encoder 3250 may be input to an IDFT 3260 block.
  • the IDFT 3260 block performs inverse discrete Fourier transform (IDFT) or inverse Fast Fourier transform (IFFT).
  • IDFT inverse discrete Fourier transform
  • IFFT inverse Fast Fourier transform
  • the output of the IDFT 3260 block is input to the Guard Interval (GI) inserter 3270, and the output of the GI inserter 3270 is input to the transceiver 3130 of FIG. 31.
  • GI Guard Interval

Abstract

L'invention concerne un procédé et un dispositif de transmission d'une trame de réveil dans un système RLE sans fil. En particulier, le dispositif de transmission configure une PPDU à laquelle un premier système RLE sans fil est appliqué. Le dispositif de transmission transmet, par l'intermédiaire de la PPDU, une trame de réveil à laquelle un second système RLE sans fil est appliqué. La PPDU comprend un champ de signal et un champ de données. Le champ de signal indique qu'une trame de données est transmise dans au moins une RU excluant trois 26-RU, située au centre d'une bande de fréquence prédéfinie, et une première 52-RU ou une seconde 52-RU située aux deux extrémités de la bande de fréquence prédéfinie. La trame de réveil est transmise à l'aide des trois 26-RU et de la première 52-RU ou de la seconde 52-RU. La trame de réveil comporte un schéma OOK qui lui est appliqué à et comprend ainsi un signal de marche et un signal d'arrêt.
PCT/KR2018/003895 2017-04-04 2018-04-03 Procédé et dispositif de transmission de paquet de réveil dans un système rle sans fil WO2018186648A1 (fr)

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