WO2019190221A1 - Procédé et dispositif d'émission d'un paquet de réveil dans un système de lan sans fil - Google Patents

Procédé et dispositif d'émission d'un paquet de réveil dans un système de lan sans fil Download PDF

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Publication number
WO2019190221A1
WO2019190221A1 PCT/KR2019/003633 KR2019003633W WO2019190221A1 WO 2019190221 A1 WO2019190221 A1 WO 2019190221A1 KR 2019003633 W KR2019003633 W KR 2019003633W WO 2019190221 A1 WO2019190221 A1 WO 2019190221A1
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Prior art keywords
ppdu
cascade
signal
field
length
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English (en)
Korean (ko)
Inventor
임동국
박은성
천진영
최진수
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LG Electronics Inc
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LG Electronics Inc
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L9/00—Cryptographic mechanisms or cryptographic arrangements for secret or secure communications; Network security protocols
    • H04L9/40—Network security protocols
    • 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
    • H04L27/04—Modulator circuits; Transmitter circuits
    • 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
    • H04W28/00—Network traffic management; Network resource management
    • H04W28/02—Traffic management, e.g. flow control or congestion control
    • H04W28/06—Optimizing the usage of the radio link, e.g. header compression, information sizing, discarding information
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W52/00—Power management, e.g. Transmission Power Control [TPC] 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 by applying a OOK scheme 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 by applying a OOK scheme in a WLAN system.
  • An example of the present specification proposes a method and apparatus for transmitting a wake-up packet to a WLAN system.
  • This embodiment is performed in a transmitter, the receiver may correspond to a low power wake-up receiver, and the transmitter may correspond to an AP.
  • This embodiment describes a case in which a wake-up packet transmitted to wake up a primary radio is transmitted to a plurality of receivers through a wide bandwidth or multi-channel.
  • a data rate applied to the wakeup packet may vary according to channel conditions between the transmitter and the plurality of receivers, and thus, a length difference of the WUR PPDU transmitted in each channel may occur.
  • This embodiment proposes a method of matching lengths of WUR PPDUs transmitted through respective channels in order to prevent a third party device from performing channel access for a channel of a short WUR PPDU.
  • the transmission of the WUR PPDU over a wide bandwidth means that the WUR PPDU per 20 MHz band within a wide bandwidth is transmitted by applying a frequency division multiplexing access (FDMA) scheme. Therefore, this embodiment can be said that WUR FDMA is applied.
  • FDMA frequency division multiplexing access
  • 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 broadband may be 40 MHz, 80 MHz, or 160 MHz.
  • the transmitter generates a wake-up packet by applying an On-Off Keying (OOK) method.
  • OOK On-Off Keying
  • the transmitter transmits the wake-up packet to the receiver through the broadband.
  • the wakeup packet includes a first PDU protocol data unit (PPDU) and a second PPDU.
  • the first and second PPDUs are WUR (Wake-Up Radio) PPDUs.
  • the first PPDU includes a first payload field having a first sync field and a first data rate.
  • the second PPDU includes at least one cascade PPDU and a padding field.
  • the at least one cascade PPDU includes a second payload field having a second sink field and a second data rate.
  • the at least one cascade PPDU is a PPDU that is continuously transmitted such that the length of the second PPDU matches the length of the first PPDU.
  • the first PPDU is generated by inserting a first sequence into 13 consecutive subcarriers in the first subband of the wideband and performing an Inverse Fast Fourier Transform (IFFT).
  • IFFT Inverse Fast Fourier Transform
  • the second PPDU is generated by inserting a second sequence into 13 consecutive subcarriers in the second wideband of the wideband and performing IFFT.
  • a low data rate (LDR) is applied to a first PPDU transmitted in the first subband of the wideband
  • a high data rate (HDR) is applied to a second PPDU transmitted in the second subband of the wideband.
  • LDR low data rate
  • HDR high data rate
  • the length of the first PPDU and the length of the second PPDU did not match. That is, since the length of the second PPDU to which HDR is applied is shorter than the length of the first PPDU to which LDR is applied, the channel for the second subband can be accessed from the third party device from the time point at which the second PPDU is transmitted. There was a risk of a crash.
  • the present embodiment proposes a method of consistently transmitting a cascade PPDU to match the length of the first PPDU and the second PPDU.
  • the at least one cascade PPDU may be continuously transmitted based on cascade indication information. If the cascade indication information is set to 1, there are additional PPDUs to be continuously transmitted in the at least one cascade PPDU. If the cascade indication information is set to 0, there are no additional PPDUs to be continuously transmitted in the at least one cascade PPDU. That is, the reception apparatus may determine whether the cascade PPDU currently received is the last PPDU or another PPDU to be received later through the cascade indication information.
  • the second payload field may include a MAC header.
  • the MAC header may include a frame control field.
  • the cascade indication information may be transmitted through a reserved bit in the frame control field.
  • the frame control field may further include a length field.
  • the length field may include information on the length of the at least one cascade PPDU. That is, the reception apparatus may confirm the length of the cascade PPDU currently received through the length field, thereby confirming the transmission time of the next PPDU to be received.
  • the first data rate may be determined by the first sink field.
  • the second data rate may be determined by the second sink field.
  • the first data rate may be 62.5 kb / s
  • the second data rate may be 62.5 kb / s or 250 kb / s. That is, the at least one cascade PPDU may be LDR applied to each PPDU or HDR may be applied. This may be determined by the sync field included in each cascade PPDU.
  • the at least one cascade PPDU may include a first cascade PPDU and a second cascade PPDU.
  • the data rate of the payload field included in the first cascade PPDU may be 62.5 kb / s or 250 kb / s.
  • the data rate of the payload field included in the second cascade PPDU may be 62.5 kb / s or 250 kb / s.
  • the size of the frame body field included in the first cascade PPDU may be 0, 8, or 16 bytes.
  • the size of the frame body field included in the second cascade PPDU may be 0, 8, or 16 bytes.
  • the frame control field may further include a type field.
  • the first and second cascade PPDUs are based on the type field, wake-up beacon, wake-up frame and wake-up vendor specific frame. It can be determined as one of the.
  • the receiving device may include a first STA, a second STA, and a third STA.
  • the first PPDU may be transmitted in the first subband for the first STA.
  • the first cascade PPDU may be transmitted in the second subband for the second STA.
  • the second cascade PPDU may be transmitted in the second subband for the third STA.
  • the sum of the length of the first sink field and the length of the first data rate may be equal to the sum of the length of the at least one cascade PPDU and the padding field length.
  • the first and second sequences may be set to a 13 length sequence or a 7 length sequence based on the first data rate and the second data rate.
  • the first subband and the second subband may be a 20 MHz band.
  • the IFFT may be a 64 point IFFT.
  • 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.
  • 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.
  • 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 illustrates a low power wake-up receiver in an environment in which data is not received.
  • FIG. 5 illustrates a low power wake-up receiver in an environment in which data is received.
  • FIG. 6 shows an example of a wakeup packet structure according to the present embodiment.
  • FIG. 7 shows a signal waveform of a wakeup packet according to the present embodiment.
  • FIG. 8 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.
  • FIG. 10 is an explanatory diagram of a Manchester coding scheme according to the present embodiment.
  • FIG. 11 illustrates various examples of a symbol repetition technique of repeating n symbols according to the present embodiment.
  • FIG. 13 shows an example of configuring a 2us on signal based on signal masking according to the present embodiment.
  • FIG. 14 shows a format structure of a WUR frame.
  • FIG. 15 shows a format structure of a Frame Control field in a WUR frame.
  • FIG 16 shows an example of a wakeup packet structure to which the sync part according to the present embodiment is applied.
  • FIG. 17 illustrates an example of a wakeup packet structure transmitted through a 40 MHz band according to the present embodiment.
  • FIG. 18 shows an example of a wakeup packet structure transmitted through the 80 MHz band according to the present embodiment.
  • FIG 19 shows an example of a wakeup packet structure transmitted through a 160 MHz band according to the present embodiment.
  • 21 illustrates an example of configuring a PPDU in a cascade manner to match the length of the PPDU in a 40 MHz band to which WUR FDMA is applied.
  • FIG. 22 shows another example of configuring a PPDU in a cascade manner to match the length of the PPDU in a 40 MHz band to which WUR FDMA is applied.
  • FIG. 23 illustrates an example of adding padding to a primary 20 MHz channel to match a length of a PPDU in an 80 MHz band to which WUR FDMA is applied.
  • FIG. 24 illustrates an example in which lengths of WUR PPDUs transmitted in respective channels do not match in an 80 MHz band to which WUR FDMA is applied.
  • FIG. 25 shows another example in which the lengths of the WUR PPDUs transmitted in each channel do not match in the 80 MHz band to which WUR FDMA is applied.
  • FIG. 26 illustrates an example of configuring LDR of a WUR PPDU transmitted in a primary 20 MHz channel in a 40 MHz band to which WUR FDMA is applied.
  • FIG. 27 illustrates an example of setting a length of an FB of a WUR PPDU transmitted in a primary 20 MHz channel in an 80 MHz band to which WUR FDMA is applied.
  • 29 is a flowchart illustrating a procedure of transmitting a wake-up packet by applying the OOK scheme according to the present embodiment.
  • FIG. 30 is a flowchart illustrating a procedure of receiving a wakeup packet by applying the OOK method according to the present embodiment.
  • FIG. 31 illustrates an apparatus for implementing the method as described above.
  • 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.).
  • the PPDU used in the IEEE standard is mainly described as a PPDU structure transmitted over a channel bandwidth of 20 MHz.
  • the PPDU structure transmitted on a bandwidth wider than the channel bandwidth of 20 MHz may be a structure in which linear scaling of the PPDU structure used in the channel bandwidth of 20 MHz is applied.
  • 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.
  • 4 illustrates a low power wake-up receiver in an environment in which data is not received.
  • 5 illustrates a low power wake-up receiver in an environment in which data is received.
  • one way to implement 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 420 is turned off and the low power wake-up receiver 430 is turned on without receiving data.
  • LP-WUR low power wake-up receiver
  • the low power wakeup receiver 530 may receive the entire Wi-Fi / BT / BLE radio 520 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 520, but only a part of the Wi-Fi / BT / BLE radio 520 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 530 may wake up the main radio 520 based on the wake-up packet transmitted from the transmitter 500.
  • the transmitter 500 may be set to transmit a wakeup packet to the receiver 510.
  • the low power wake-up receiver 530 may be instructed to wake up the main radio 520.
  • FIG. 6 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 600.
  • the receiving device may be configured to process the received wakeup packet 600.
  • the wakeup packet 600 may include a legacy preamble or any other preamble 610 as defined by the IEEE 802.11 specification.
  • the wakeup packet 600 may include a payload 620.
  • Legacy preambles provide coexistence with legacy STAs.
  • the legacy preamble 610 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 610.
  • the 802.11 STA can know the end of the packet through the L-SIG field in the legacy preamble 610.
  • 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 610 is a field for third party legacy STAs (STAs not including LP-WUR).
  • the legacy preamble 610 is not decoded from the LP-WUR.
  • the payload 620 may include a wakeup preamble 622.
  • Wake-up preamble 622 may include a sequence of bits configured to identify wake-up packet 600.
  • the wakeup preamble 622 may include, for example, a PN sequence.
  • the payload 620 may include a MAC header 624 including address information of a receiver receiving the wakeup packet 600 or an identifier of the receiver.
  • the payload 620 may include a frame body 626 that may include other information of the wakeup packet.
  • the frame body 626 may include length or size information of the payload.
  • the payload 620 may include a Frame Check Sequence (FCS) field 628 that includes 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 624 and the frame body 626.
  • FIG. 7 shows a signal waveform of a wakeup packet according to the present embodiment.
  • the wakeup packet 700 includes a legacy preamble (802.11 preamble, 710) and a payload modulated by OOK. That is, the legacy preamble and the new LP-WUR signal waveform coexist.
  • the legacy preamble 710 may be modulated according to the OFDM modulation scheme. That is, the legacy preamble 710 is not applied to the OOK method.
  • the payload may be modulated according to the OOK method.
  • the wakeup preamble 722 in the payload may be modulated according to another modulation scheme.
  • 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. 8 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. 8 information in the form of a binary sequence having 10 bit values is used.
  • FIG. 8 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
  • the bit value is 0,
  • the transmitter is turned off
  • the symbol is turned on at 6 bit values out of 10 bit values.
  • 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.
  • 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.
  • the 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).
  • FIG. 10 is an explanatory diagram of a Manchester coding scheme 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. 10, 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 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. 11 illustrates various examples of a symbol repetition technique of repeating n symbols according to the present embodiment.
  • Option 1 Information 0 and information 1 may be repeatedly represented by the same symbol n times as shown in FIG.
  • information 0 and information 1 may be repeatedly represented by different symbols n times.
  • one half of a symbol may be configured as information 0 and the other half may be configured as information 1 to represent n symbols.
  • the total number of 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 a symbol carrying one piece of information.
  • a symbol using a symbol reduction technique is used to represent one bit, and a specific sequence is applied to every available subcarrier (for example, 13) in m units, and the remaining coefficients are set to 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. 12 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
  • FIG. 13 shows an example of configuring a 2us on signal based on signal masking according to the present embodiment.
  • FIG. 13 proposes a masking based technique using a sequence of length 13 (all coefficients are inserted into 13 consecutive subcarriers in the 20 MHz band).
  • a 4us OOK symbol may be generated.
  • a 64-point IFFT is applied to 13 consecutive subcarriers of 20 MHz band to perform a 64-point IFFT, and a 4us OOK symbol is generated by adding 0.8us CP or GI.
  • the 2us on signal may be configured by masking half of the 4us OOK symbol.
  • the information 0 may take the first half of the 4us symbol to configure the 2us on signal.
  • the latter half of the 4us symbol does not transmit any information and thus can constitute a 2us off signal.
  • information 1 may take a half part of the symbol to form a 2us false signal.
  • the front half of the 4us symbol can configure a 2us off signal by not transmitting any information.
  • FIG. 14 shows a format structure of a WUR frame.
  • the MAC header of the WUR frame includes a Frame Control field, an ID field, and a Type Dependent Control field.
  • the Frame Body field may optionally be present only in certain WUR frame types.
  • the WUR frame type will be described later.
  • WUR frames without the Frame Body field are called fixed-length (FL) WUR frames.
  • WUR frames with the Frame Body field are called variable-length (VL) WUR frames.
  • the FCS field includes a 16-bit cyclic redundancy check (CRC) when the Protected subfield in the Frame Control field is 0, and includes a 16-bit Message Integrity Check (MIC) when the Protected subfield in the Frame Control field is 1.
  • CRC cyclic redundancy check
  • MIC Message Integrity Check
  • the ID field (or address field) may be defined as follows.
  • the WID is a WUR ID provided by the AP and identifies one WUR STA.
  • the GID is a Group ID provided by the AP and identifies one or more WUR STAs.
  • TXID is a transmitter ID determined by the AP.
  • OUI1 is 12 MSB (s) of the OUI.
  • FIG. 15 shows a format structure of a Frame Control field in a WUR frame.
  • the Frame Control field may have two format structures.
  • the Type subfield in the Frame Control field indicates the type of a WUR frame.
  • the WUR frame type is defined as follows.
  • the Protected subfield in the Frame Control field indicates whether information carried in the WUR frame is understood and processed by the MIC algorithm. If the WUR frame is protected using the MIC algorithm, the Protected subfield is set to '1'. If a WUR frame is not protected using the MIC algorithm, the Protected subfield is set to 0 and the WUR frame is indicated to contain a CRC for the WUR frame.
  • the Length Present subfield indicates that the Length / Misc subfield indicates the Length subfield. Indicates whether or not to include it.
  • the Length / Misc subfield includes a Length subfield when the Length Present subfield is set to 1.
  • the Length / Misc subfield includes a Misc subfield unless the Length Present subfield is set to 1.
  • the Length subfield indicates the length of the Frame Body field. Misc subfields are reserved unless otherwise specified.
  • a reserved field is configured at the end of the frame control field.
  • the reserved field may be used as a cascade indicator.
  • various data rates may be applied to the payload of the WUR PPDU in an 802.11ba system, and two types of sync parts or sync fields having different lengths may be used to reduce the overhead of the WUR PPDU.
  • WUR PPDU can be configured.
  • various schemes for indicating a data rate applied to a payload using two types of sink parts or sink fields are proposed.
  • the WUR signal may transmit the WUR signal to the STA using 4 MHz in each 20 MHz using FDMA.
  • the data rate for transmitting the WUR signal may be set differently according to the channel condition between the AP and the STA at each 20MHz, and may also include a frame body (FB) having a different length according to the frame type. As such, a difference in length between WUR PPDUs of each channel occurs during FDMA transmission according to the data rate and the length of the FB.
  • FB frame body
  • the present invention proposes a method for configuring a PPDU of a primary channel when transmitting through FDMA.
  • FIG 16 shows an example of a wakeup packet structure to which the sync part according to the present embodiment is applied.
  • 16 is an example of a WUR PPDU to which a sync part (or sync field) is applied in an IEEE 802.11ba system.
  • the WRU signal for waking up the primary radio may be transmitted using a frame format as shown in FIG. 16.
  • the WUR frame may be configured to transmit an L-Part first before the WUR part for coexistence with legacy.
  • the WUR part may include a WUR-sync field and a WUR-payload field as described above, and the WUR-payload includes control information rather than data for a device.
  • the L-PART is used for the third party device, not the WUR receiver, and the WUR receiver may not decode the L-part.
  • the preamble of the WUR consists of a non WUR portion and a WUR sync field, and can indicate data rate information used for payload using the WUR sync field.
  • the length of the WUR sync field is as follows according to the data rate. .
  • the WUR-payload may also vary depending on the frame body size.
  • the WUR PPDU can be transmitted using wide bandwidth differently from FIG. 16.
  • the WUR PPDU transmitted using wide bandwidth e.g. 40 MHz / 80 MHz / 160 MHz
  • the transmission of the WUR PPDU over the wide bandwidth indicates that the WUR PPDU is transmitted with WUR Frequency Division Multiplexing Access (FDMA) applied.
  • FDMA Frequency Division Multiplexing Access
  • FIG. 17 illustrates an example of a wakeup packet structure transmitted through a 40 MHz band according to the present embodiment.
  • FIG. 18 shows an example of a wakeup packet structure transmitted through the 80 MHz band according to the present embodiment.
  • FIG 19 shows an example of a wakeup packet structure transmitted through a 160 MHz band according to the present embodiment.
  • the legacy preamble and the BPSK mark which are non WUR portions, are duplexed and transmitted in units of 20 MHz.
  • the WUR portion, the WUR sync field and the WUR payload are transmitted using a 4 MHz bandwidth (13 tone or subcarriers) centered on a center frequency within a 20 MHz channel.
  • the data rate for transmitting the WUR signal per 20 MHz may be different according to the state of each channel. For example, when transmitting a WUR signal using FDMA at 40 MHz, if a high data rate (ie HDR) and a low data rate (ie LDR) are applied to WUR DATA for each 20 MHz, the lengths of the WUR PPDUs are different from each other as shown in FIG. 20. The lengths of the WUR PPDUs do not match.
  • ie HDR high data rate
  • LDR low data rate
  • the WUR PPDU may be configured and transmitted through the following method.
  • 21 illustrates an example of configuring a PPDU in a cascade manner to match the length of the PPDU in a 40 MHz band to which WUR FDMA is applied.
  • the AP matches the PPDU alignment with respect to the PPDU length of the channel having the max PPDU length.
  • the WUR PPDUs are continuously configured as shown in FIG. 21 to match the PPDU alignment.
  • the remaining lengths are padded to match the PPDU lengths equally between channels.
  • the WUR FDMA PPDU configured as described above may be configured as shown in FIG. 21 at 40 MHz, for example.
  • the WUR PPDUs continuously attached to match the length of the PPDU are configured to include a WUR sync field and use a subfield of the Mac header of the WUR PPDU to indicate that the WUR PPDU is transmitted to the cascade.
  • a reserved bit is used in a frame control field which is a subfield of a WUR MAC header.
  • the reserved bit is used as a cascade indicator and is set to 1 when cascade PPDU is configured.
  • the STA can recognize that there is another PPDU after the current PPDU through the cascade indicator, and can start the next PPDU by using the length field which is a subfield of the frame control field. That is, the STA knows only the length of its own PPDU by using the length field, thereby knowing the start of the next PPDU (STA knows that cascade transmission is performed through the cascade indicator).
  • STAs allocated to the secondary 20 MHz channel may decode their cascade PPDUs.
  • the PPDU uses the same data rate for cascade transmission. For example, different data rates may be applied to each cascaded PPDU.
  • the STA can detect the sync field and grasp information on the data rate applied to the PPDU.
  • PPDU1 may be applied by applying LDR
  • PPDU2 and PPDU3 may be transmitted by applying HDR.
  • the cascade WUR PPDU may have a different frame body size.
  • each PPDU can be configured using various FBs in cascade.
  • PPDU1 may have an FB of 0 bytes
  • PPDU2 may be composed of 8 bytes
  • PPDU3 may be composed of FBs of 16 bytes.
  • the STA since the STA may determine the size of the PPDU through the length field of the MAC header, the STA does not perform decoding on the padding.
  • the WUR PPDU cascaded may be configured in different WUR formats. That is, different types of WUR frames can be cascaded and transmitted. For example, when two or more WUR PPDUs are cascaded and transmitted, the value of the type field included in the frame control field, which is a subfield of the mac header included in each WUR PPDU, is transmitted differently. That is, each PPDU added during cascade WUR PPDU transmission may be composed of a different type or the same type. In this case, the PPDU is set to one of the following types and transmitted. (See Table 16 above)
  • Vendor specific frame (frame that informs the operator or device specific information)
  • FIG. 22 shows another example of configuring a PPDU in a cascade manner to match the length of the PPDU in a 40 MHz band to which WUR FDMA is applied.
  • the length of the PPDU is matched to the MAX PPDU length.
  • the WUR PPDU added to match the alignment of the PPDU length is composed of only the WUR data field without WUR sync.
  • the STA receiving the WUR signal through the channel through which the cascade PPDU is transmitted sets the timing of the PPDU using a sync sequence and then sets the cascade transmission indicator included in the MAC header. Through this, you can see that the PPDU is cascaded and transmitted.
  • the cascade transmission indicator indicates that the PPDU is cascaded and transmitted and that the WUR sync field is not included in the cascade PPDU. Accordingly, the STAs decode the cascade PPDU using the data rate identified through the WUR synch field transmitted first.
  • cascade PPDUs are generated using the same data rate.
  • each PPDU can be configured to include different sized FBs, and the STA can know the length of the cascade PPDU and the starting point of the next cascade PPDU using the length field included in the MAC header of the PPDU. have.
  • the STA since the STA may determine the size of the PPDU through the length field of the MAC header, the STA does not perform decoding on the padding.
  • the WUR PPDU cascaded may be configured in different WUR formats. That is, different types of WUR frames can be cascaded and transmitted. For example, when two or more WUR PPDUs are cascaded and transmitted, the value of the type field included in the frame control field, which is a subfield of the mac header included in each WUR PPDU, is transmitted differently. That is, each PPDU added during cascade WUR PPDU transmission may be composed of a different type or the same type. In this case, the PPDU is set to one of the following types and transmitted. (See Table 16.) In (2), unlike the above (1), the sync field is not included in the cascade PPDU of the following type.
  • the PPDUs transmitted for each channel are repeatedly repeated for PPDU length for PPDU alignment. You can also match the alignment.
  • FIG. 23 illustrates an example of adding padding to a primary 20 MHz channel to match a length of a PPDU in an 80 MHz band to which WUR FDMA is applied.
  • the channel having the maximum PPDU length may not be the primary 20 MHz. In this case, the primary channel always adds padding to match the maximum PPDU length.
  • the STA in the BSS performs carrier sensing on the primary channel to transmit and receive a signal through the primary channel. Therefore, if the length of PPDU transmitted through primary 20MHz channel is smaller than PPDU of other channel during FDMA transmission, if the length does not match by adding padding, it determines that channel is idle and performs channel access and UL transmission. However, since the AP is transmitting a WUR through FDMA, the STA cannot receive a signal transmitted by using the primary channel and thus cannot transmit a response to the signal transmitted by the STA. Therefore, the STA performs channel access and retransmission again during the PPDU length difference, thereby performing unnecessary operations. In order to prevent unnecessary operations of these STAs, the PPDU transmitted through the primary channel during FDMA transmission adds padding according to the Max PPDU length among the PPDU lengths transmitted through various channels.
  • padding is performed only for the primary channel. This is because the legacy STA performs carrier sensing only on the primary channel, so that the legacy STA only needs to configure the channel to be busy in terms of the legacy STA. If the legacy STA determines that the primary channel is busy, the legacy STA determines that the secondary channel is also busy.
  • the WUR PPDU transmitted through the primary channel like the cascade PPDU transmission is repeatedly transmitted or has a different frame type. It can be sent by adding a WUR PPDU.
  • the type of WUR PPDU added is set to one of the following frame types and transmitted. (See Table 16 above)
  • FIG. 24 illustrates an example in which lengths of WUR PPDUs transmitted in respective channels do not match in an 80 MHz band to which WUR FDMA is applied.
  • the WUR PPDU transmitted using 4 MHz per 20 MHz has different lengths according to the state of each channel and the WUR frame type.
  • the WUR signal transmission through the primary channel ends first while the AP transmits the wake up signal to the STA through FDMA. do.
  • the STA (ex. In BSS, in OBSS) determines that the primary channel is idle and performs signal transmission through the primary channel.
  • the AP when an STA in a BSS transmits a signal through a primary channel, the AP cannot receive a signal transmitted by the STA to Uplink since the AP already transmits a wake-up signal using FDMA. During the period, unnecessary signal transmission and retransmission are repeatedly performed, thus performing unnecessary operation and unnecessary power consumption.
  • the STA of the OBSS uses the primary channel, it may be affected by the adjacent channel interference due to the use of the channel, and wake up of the AP because the primary channel is already used by another STA before the WUR PPDU transmission is completed. After the signal transmission, more channel access time may be required for the STA to transmit and receive the signal through the primary channel.
  • FIG. 25 shows another example in which the lengths of the WUR PPDUs transmitted in each channel do not match in the 80 MHz band to which WUR FDMA is applied.
  • the length of the WUR PPDU transmitted through the primary channel has a length greater than the max length among the lengths of the WUR PPDU transmitted through another 20 MHz channel or the length of the Max PPDU. It may be configured to have the same length as.
  • a WUR PPDU may be formed using the following method to make the length of the primary channel longer than other channels or to match the max PPDU length transmitted through another channel. Can be configured.
  • FIG. 26 illustrates an example of configuring LDR of a WUR PPDU transmitted in a primary 20 MHz channel in a 40 MHz band to which WUR FDMA is applied.
  • A. PPDU transmitted through primary channel is configured by applying LDR
  • the WUR PPDU transmitted through the primary channel is configured by applying a low data rate.
  • PPDU configured with LDR ie low data rate
  • HDR ie high data rate
  • WUR signal through FDMA because data field is composed of 4 times longer 16us symbol units. It can be prevented that the length of the PPDU transmitted through the primary channel is smaller than the length of the WUR PPDU of another channel during transmission.
  • the WUR PPDU is configured by applying LDR so that the length of the WUR PPDU transmitted through the primary channel always has the same or larger length than the max PPDU size of other channels.
  • the frame body included in the WUR frame consists of 0/8/16 octets. Therefore, even if LDR is applied to prevent the primary channel ending early in WUR FDMA transmission, if the frame body is small, the primary channel may be smaller than other channels. Accordingly, during FDMA transmission, the primary channel configures a WUR PPDU by applying the length of the Max Frame body and LDR transmitted through another channel to prevent the transmission through the primary channel before ending the other channel.
  • the primary channel configures a WUR PPDU using a large frame body.
  • FIG. 27 illustrates an example of setting a length of an FB of a WUR PPDU transmitted in a primary 20 MHz channel in an 80 MHz band to which WUR FDMA is applied.
  • the PPDU of the primary channel constitutes a WUR PPDU including an 8/16 byte FB.
  • the length of the PPDU transmitted through the primary channel can be set longer, so that another STA in the BSS can use the primary channel while the AP transmits the wake-up signal using the FDMA.
  • the STA may limit the channel access and signal transmission through the channel in the OBSS.
  • WUR PPDUs transmitted through the primary channel are repeatedly transmitted to set the PPDU to a length equal to or greater than the Max PPDU size of another channel.
  • the PPDU repeatedly transmitted through the primary channel may be configured as follows.
  • the WUR PPDU (ie, WUR Preamble field + WUR data field) may be repeated two or more times to configure the WUR PPDU.
  • a WUR PPDU of another STA or another type frame is added after the WUR PPDU.
  • PPDU can be configured.
  • the added WUR PPDU format is configured using one type defined in the type field of a WUR header (MAC header).
  • the added WUR PPDU is set to one of the following types and transmitted. (See Table 16 above)
  • the WUR PPDU composed of the WUR frame added for alignment may not include wake-up information. That is, it may be an empty PPDU for length alignment.
  • an indication can be made by setting a new type field, that is, defining an empty wake-up frame.
  • the empty PPDU indication can be indicated by using a reserved 1 bit of the frame control field.
  • the indication may be indicated by using an address field, and for this purpose, an address field for an empty PPDU may be defined or specific bit information of the address field may be used to indicate an empty PPDU.
  • bit sequence for 000000000000 or 111111111111 in the 12-bit address field can be set to empty PPDU ID and used for indication.
  • 29 is a flowchart illustrating a procedure of transmitting a wake-up packet by applying the OOK scheme according to the present embodiment.
  • FIG. 29 An example of FIG. 29 is performed in a transmitter, the receiver may correspond to a low power wake-up receiver, and the transmitter may correspond to an AP.
  • This embodiment describes a case in which a wake-up packet transmitted to wake up a primary radio is transmitted to a plurality of receivers through a wide bandwidth or multi-channel.
  • a data rate applied to the wakeup packet may vary according to channel conditions between the transmitter and the plurality of receivers, and thus, a length difference of the WUR PPDU transmitted in each channel may occur.
  • This embodiment proposes a method of matching lengths of WUR PPDUs transmitted through respective channels in order to prevent a third party device from performing channel access for a channel of a short WUR PPDU.
  • the transmission of the WUR PPDU over a wide bandwidth means that the WUR PPDU per 20 MHz band within a wide bandwidth is transmitted by applying a frequency division multiplexing access (FDMA) scheme. Therefore, this embodiment can be said that WUR FDMA is applied.
  • FDMA frequency division multiplexing access
  • 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 broadband may be 40 MHz, 80 MHz, or 160 MHz.
  • the transmitter In operation S2910, the transmitter generates a wakeup packet by applying an on-off keying (OOK) scheme.
  • OOK on-off keying
  • the transmitter transmits the wakeup packet to the receiver through the broadband.
  • the wakeup packet includes a first PDU protocol data unit (PPDU) and a second PPDU.
  • the first and second PPDUs are WUR (Wake-Up Radio) PPDUs.
  • the first PPDU includes a first payload field having a first sync field and a first data rate.
  • the second PPDU includes at least one cascade PPDU and a padding field.
  • the at least one cascade PPDU includes a second payload field having a second sink field and a second data rate.
  • the at least one cascade PPDU is a PPDU that is continuously transmitted such that the length of the second PPDU matches the length of the first PPDU.
  • the first PPDU is generated by inserting a first sequence into 13 consecutive subcarriers in the first subband of the wideband and performing an Inverse Fast Fourier Transform (IFFT).
  • IFFT Inverse Fast Fourier Transform
  • the second PPDU is generated by inserting a second sequence into 13 consecutive subcarriers in the second wideband of the wideband and performing IFFT.
  • a low data rate (LDR) is applied to a first PPDU transmitted in the first subband of the wideband
  • a high data rate (HDR) is applied to a second PPDU transmitted in the second subband of the wideband.
  • LDR low data rate
  • HDR high data rate
  • the length of the first PPDU and the length of the second PPDU did not match. That is, since the length of the second PPDU to which HDR is applied is shorter than the length of the first PPDU to which LDR is applied, the channel for the second subband can be accessed from the third party device from the time point at which the second PPDU is transmitted. There was a risk of a crash.
  • the present embodiment proposes a method of consistently transmitting a cascade PPDU to match the length of the first PPDU and the second PPDU.
  • the at least one cascade PPDU may be continuously transmitted based on cascade indication information. If the cascade indication information is set to 1, there are additional PPDUs to be continuously transmitted in the at least one cascade PPDU. If the cascade indication information is set to 0, there are no additional PPDUs to be continuously transmitted in the at least one cascade PPDU. That is, the reception apparatus may determine whether the cascade PPDU currently received is the last PPDU or another PPDU to be received later through the cascade indication information.
  • the second payload field may include a MAC header.
  • the MAC header may include a frame control field.
  • the cascade indication information may be transmitted through a reserved bit in the frame control field.
  • the frame control field may further include a length field.
  • the length field may include information on the length of the at least one cascade PPDU. That is, the reception apparatus may confirm the length of the cascade PPDU currently received through the length field, thereby confirming the transmission time of the next PPDU to be received.
  • the first data rate may be determined by the first sink field.
  • the second data rate may be determined by the second sink field.
  • the first data rate may be 62.5 kb / s
  • the second data rate may be 62.5 kb / s or 250 kb / s. That is, the at least one cascade PPDU may be LDR applied to each PPDU or HDR may be applied. This may be determined by the sync field included in each cascade PPDU.
  • the at least one cascade PPDU may include a first cascade PPDU and a second cascade PPDU.
  • the data rate of the payload field included in the first cascade PPDU may be 62.5 kb / s or 250 kb / s.
  • the data rate of the payload field included in the second cascade PPDU may be 62.5 kb / s or 250 kb / s.
  • the size of the frame body field included in the first cascade PPDU may be 0, 8, or 16 bytes.
  • the size of the frame body field included in the second cascade PPDU may be 0, 8, or 16 bytes.
  • the frame control field may further include a type field.
  • the first and second cascade PPDUs are based on the type field, wake-up beacon, wake-up frame and wake-up vendor specific frame. It can be determined as one of the.
  • the receiving device may include a first STA, a second STA, and a third STA.
  • the first PPDU may be transmitted in the first subband for the first STA.
  • the first cascade PPDU may be transmitted in the second subband for the second STA.
  • the second cascade PPDU may be transmitted in the second subband for the third STA.
  • the sum of the length of the first sink field and the length of the first data rate may be equal to the sum of the length of the at least one cascade PPDU and the padding field length.
  • the first and second sequences may be set to a 13 length sequence or a 7 length sequence based on the first data rate and the second data rate.
  • the first subband and the second subband may be a 20 MHz band.
  • the IFFT may be a 64 point IFFT.
  • 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.
  • FIG. 30 is a flowchart illustrating a procedure of receiving a wakeup packet by applying the OOK method according to the present embodiment.
  • FIG. 30 An example of FIG. 30 is performed in a receiving apparatus, which may correspond to a low power wake-up receiver, and the transmitting apparatus may correspond to an AP.
  • This embodiment describes a case in which a wake-up packet transmitted to wake up a primary radio is transmitted to a plurality of receivers through a wide bandwidth or multi-channel.
  • a data rate applied to the wakeup packet may vary according to channel conditions between the transmitter and the plurality of receivers, and thus, a length difference of the WUR PPDU transmitted in each channel may occur.
  • This embodiment proposes a method of matching lengths of WUR PPDUs transmitted through respective channels in order to prevent a third party device from performing channel access for a channel of a short WUR PPDU.
  • the transmission of the WUR PPDU over a wide bandwidth means that the WUR PPDU per 20 MHz band within a wide bandwidth is transmitted by applying a frequency division multiplexing access (FDMA) scheme. Therefore, this embodiment can be said that WUR FDMA is applied.
  • FDMA frequency division multiplexing access
  • one of a plurality of receivers may receive a wakeup packet through the wideband, and decode the wakeup packet for a band supported by the receiver.
  • 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 broadband may be 40 MHz, 80 MHz, or 160 MHz.
  • step S3010 the receiver receives a wake-up packet generated by applying the OOK (On-Off Keying) scheme from the transmitter over a broadband.
  • OOK On-Off Keying
  • the receiver decodes the wakeup packet for a band supported by the receiver.
  • the wakeup packet includes a first PDU protocol data unit (PPDU) and a second PPDU.
  • the first and second PPDUs are WUR (Wake-Up Radio) PPDUs.
  • the first PPDU includes a first payload field having a first sync field and a first data rate.
  • the second PPDU includes at least one cascade PPDU and a padding field.
  • the at least one cascade PPDU includes a second payload field having a second sink field and a second data rate.
  • the at least one cascade PPDU is a PPDU that is continuously transmitted such that the length of the second PPDU matches the length of the first PPDU.
  • the first PPDU is generated by inserting a first sequence into 13 consecutive subcarriers in the first subband of the wideband and performing an Inverse Fast Fourier Transform (IFFT).
  • IFFT Inverse Fast Fourier Transform
  • the second PPDU is generated by inserting a second sequence into 13 consecutive subcarriers in the second wideband of the wideband and performing IFFT.
  • a low data rate (LDR) is applied to a first PPDU transmitted in the first subband of the wideband
  • a high data rate (HDR) is applied to a second PPDU transmitted in the second subband of the wideband.
  • LDR low data rate
  • HDR high data rate
  • the length of the first PPDU and the length of the second PPDU did not match. That is, since the length of the second PPDU to which HDR is applied is shorter than the length of the first PPDU to which LDR is applied, the channel for the second subband can be accessed from the third party device from the time point at which the second PPDU is transmitted. There was a risk of a crash.
  • the present embodiment proposes a method of consistently transmitting a cascade PPDU to match the length of the first PPDU and the second PPDU.
  • the receiving device may continuously receive the at least one cascade PPDU based on the cascade indication information from the transmitting device.
  • the receiver may confirm that there are additional PPDUs to be continuously transmitted in the at least one cascade PPDU.
  • the receiver may confirm that there are no additional PPDUs to be continuously transmitted in the at least one cascade PPDU.
  • the reception apparatus may determine whether the cascade PPDU currently received is the last PPDU or another PPDU to be received later through the cascade indication information.
  • the second payload field may include a MAC header.
  • the MAC header may include a frame control field.
  • the cascade indication information may be transmitted through a reserved bit in the frame control field.
  • the frame control field may further include a length field.
  • the length field may include information on the length of the at least one cascade PPDU. That is, the reception apparatus may confirm the length of the cascade PPDU currently received through the length field, thereby confirming the transmission time of the next PPDU to be received.
  • the first data rate may be determined by the first sink field.
  • the second data rate may be determined by the second sink field.
  • the first data rate may be 62.5 kb / s
  • the second data rate may be 62.5 kb / s or 250 kb / s. That is, the at least one cascade PPDU may be LDR applied to each PPDU or HDR may be applied. This may be determined by the sync field included in each cascade PPDU.
  • the at least one cascade PPDU may include a first cascade PPDU and a second cascade PPDU.
  • the data rate of the payload field included in the first cascade PPDU may be 62.5 kb / s or 250 kb / s.
  • the data rate of the payload field included in the second cascade PPDU may be 62.5 kb / s or 250 kb / s.
  • the size of the frame body field included in the first cascade PPDU may be 0, 8, or 16 bytes.
  • the size of the frame body field included in the second cascade PPDU may be 0, 8, or 16 bytes.
  • the frame control field may further include a type field.
  • the first and second cascade PPDUs are based on the type field, wake-up beacon, wake-up frame and wake-up vendor specific frame. It can be determined as one of the.
  • the receiving device may include a first STA, a second STA, and a third STA.
  • the first STA may decode the first PPDU in the first subband.
  • the second STA may decode the first cascade PPDU in the second subband.
  • the third STA may decode the second cascade PPDU in the second subband.
  • the sum of the length of the first sink field and the length of the first data rate may be equal to the sum of the length of the at least one cascade PPDU and the padding field length.
  • the first and second sequences may be set to a 13 length sequence or a 7 length sequence based on the first data rate and the second data rate.
  • the first subband and the second subband may be a 20 MHz band.
  • the IFFT may be a 64 point IFFT.
  • 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.
  • FIG. 31 illustrates an apparatus for implementing the method as described above.
  • the wireless device 100 of FIG. 31 is a transmission device capable of implementing the above-described embodiment and may operate as an AP STA.
  • the wireless device 150 of FIG. 31 is a reception device capable of implementing the above-described embodiment and may operate as a non-AP STA.
  • the transmitter 100 may include a processor 110, a memory 120, and a transceiver 130
  • the receiver device 150 may include a processor 160, a memory 170, and a transceiver 180. can do.
  • the transceiver 130 and 180 may transmit / receive a radio signal and may be executed in a physical layer such as IEEE 802.11 / 3GPP.
  • the processors 110 and 160 are executed in the physical layer and / or the MAC layer and are connected to the transceivers 130 and 180.
  • the processors 110 and 160 and / or the transceivers 130 and 180 may include application-specific integrated circuits (ASICs), other chipsets, logic circuits, and / or data processors.
  • the memory 120, 170 may include read-only memory (ROM), random access memory (RAM), flash memory, memory card, storage medium and / or other storage unit.
  • ROM read-only memory
  • RAM random access memory
  • flash memory memory card
  • storage medium storage medium and / or other storage unit.
  • the method described above can be executed as a module (eg, process, function) that performs the functions described above.
  • the module may be stored in the memories 120 and 170 and may be executed by the processors 110 and 160.
  • the memories 120 and 170 may be disposed inside or outside the processes 110 and 160, and may be connected to the processes 110 and 160 by well-known means.
  • the processors 110 and 160 may implement the functions, processes, and / or methods proposed herein.
  • the processors 110 and 160 may perform operations according to the above-described embodiment.
  • the operation of the processor 110 of the transmitter is specifically as follows.
  • the processor 110 of the transmitting device generates a wakeup packet by applying an On-Off Keying (OOK) method, and transmits the wakeup packet to the receiving device through a broadband.
  • OOK On-Off Keying
  • the operation of the processor 160 of the receiving apparatus is as follows.
  • the receiving device may be one of a plurality of low power wake-up receivers.
  • the processor 160 of the receiving device receives a wake-up packet generated by applying an On-Off Keying (OOK) method from a transmitting device through a broadband, and decodes the wake-up packet for a band supported by the receiving device. .
  • OOK On-Off Keying
  • FIG. 32 illustrates a more detailed wireless device implementing an embodiment of the present invention.
  • the present invention described above with respect to the transmitting apparatus or the receiving apparatus can be applied to this embodiment.
  • the wireless device includes a processor 610, a power management module 611, a battery 612, a display 613, a keypad 614, a subscriber identification module (SIM) card 615, a memory 620, a transceiver 630. ), One or more antennas 631, speakers 640, and microphones 641.
  • SIM subscriber identification module
  • Processor 610 may be configured to implement the proposed functions, procedures, and / or methods described herein. Layers of the air interface protocol may be implemented in the processor 610.
  • the processor 610 may include an application-specific integrated circuit (ASIC), another chipset, a logic circuit, and / or a data processing device.
  • the processor may be an application processor (AP).
  • the processor 610 may include at least one of a digital signal processor (DSP), a central processing unit (CPU), a graphics processing unit (GPU), and a modem (modulator and demodulator).
  • DSP digital signal processor
  • CPU central processing unit
  • GPU graphics processing unit
  • modem modulator and demodulator
  • processor 610 examples include SNAPDRAGONTM series processors manufactured by Qualcomm®, EXYNOSTM series processors manufactured by Samsung®, A Series processors manufactured by Apple®, HELIOTM series processors manufactured by MediaTek®, INTEL® It may be an ATOMTM series processor or a corresponding next generation processor manufactured by.
  • the power management module 611 manages power of the processor 610 and / or the transceiver 630.
  • the battery 612 supplies power to the power management module 611.
  • the display 613 outputs the result processed by the processor 610.
  • Keypad 614 receives input to be used by processor 610. Keypad 614 may be displayed on display 613.
  • SIM card 615 is an integrated circuit used to securely store an international mobile subscriber identity (IMSI) and its associated keys used to identify and authenticate subscribers in mobile phone devices such as mobile phones and computers. You can also store contact information on many SIM cards.
  • IMSI international mobile subscriber identity
  • the memory 620 is operatively coupled with the processor 610 and stores various information for operating the processor 610.
  • the memory 620 may include read-only memory (ROM), random access memory (RAM), flash memory, memory card, storage medium, and / or other storage device.
  • ROM read-only memory
  • RAM random access memory
  • flash memory memory card
  • storage medium storage medium
  • / or other storage device When an embodiment is implemented in software, the techniques described herein may be implemented as modules (eg, procedures, functions, etc.) that perform the functions described herein.
  • the module may be stored in the memory 620 and executed by the processor 610.
  • the memory 620 may be implemented inside the processor 610. Alternatively, the memory 620 may be implemented outside the processor 610 and communicatively connected to the processor 610 through various means known in the art.
  • the transceiver 630 is operatively coupled with the processor 610 and transmits and / or receives a radio signal.
  • the transceiver 630 includes a transmitter and a receiver.
  • the transceiver 630 may include a baseband circuit for processing radio frequency signals.
  • the transceiver controls one or more antennas 631 to transmit and / or receive wireless signals.
  • the speaker 640 outputs a sound related result processed by the processor 610.
  • the microphone 641 receives a sound related input to be used by the processor 610.
  • the processor 610 In the case of a transmitter, the processor 610 generates a wakeup packet by applying an On-Off Keying (OOK) scheme, and transmits the wakeup packet to a receiver through a broadband.
  • OOK On-Off Keying
  • the processor 610 receives a wakeup packet generated by applying an On-Off Keying (OOK) scheme from a transmitting apparatus over a wideband, and the wakeup packet for a band supported by the receiving apparatus.
  • OOK On-Off Keying
  • the wakeup packet includes a first PDU protocol data unit (PPDU) and a second PPDU.
  • the first and second PPDUs are WUR (Wake-Up Radio) PPDUs.
  • the first PPDU includes a first payload field having a first sync field and a first data rate.
  • the second PPDU includes at least one cascade PPDU and a padding field.
  • the at least one cascade PPDU includes a second payload field having a second sink field and a second data rate.
  • the at least one cascade PPDU is a PPDU that is continuously transmitted such that the length of the second PPDU matches the length of the first PPDU.
  • the first PPDU is generated by inserting a first sequence into 13 consecutive subcarriers in the first subband of the wideband and performing an Inverse Fast Fourier Transform (IFFT).
  • IFFT Inverse Fast Fourier Transform
  • the second PPDU is generated by inserting a second sequence into 13 consecutive subcarriers in the second wideband of the wideband and performing IFFT.
  • a low data rate (LDR) is applied to a first PPDU transmitted in the first subband of the wideband
  • a high data rate (HDR) is applied to a second PPDU transmitted in the second subband of the wideband.
  • LDR low data rate
  • HDR high data rate
  • the length of the first PPDU and the length of the second PPDU did not match. That is, since the length of the second PPDU to which HDR is applied is shorter than the length of the first PPDU to which LDR is applied, the channel for the second subband can be accessed from the third party device from the time point at which the second PPDU is transmitted. There was a risk of a crash.
  • the present embodiment proposes a method of consistently transmitting a cascade PPDU to match the length of the first PPDU and the second PPDU.
  • the at least one cascade PPDU may be continuously transmitted based on cascade indication information. If the cascade indication information is set to 1, there are additional PPDUs to be continuously transmitted in the at least one cascade PPDU. If the cascade indication information is set to 0, there are no additional PPDUs to be continuously transmitted in the at least one cascade PPDU. That is, the reception apparatus may determine whether the cascade PPDU currently received is the last PPDU or another PPDU to be received later through the cascade indication information.
  • the second payload field may include a MAC header.
  • the MAC header may include a frame control field.
  • the cascade indication information may be transmitted through a reserved bit in the frame control field.
  • the frame control field may further include a length field.
  • the length field may include information on the length of the at least one cascade PPDU. That is, the reception apparatus may confirm the length of the cascade PPDU currently received through the length field, thereby confirming the transmission time of the next PPDU to be received.
  • the first data rate may be determined by the first sink field.
  • the second data rate may be determined by the second sink field.
  • the first data rate may be 62.5 kb / s
  • the second data rate may be 62.5 kb / s or 250 kb / s. That is, the at least one cascade PPDU may be LDR applied to each PPDU or HDR may be applied. This may be determined by the sync field included in each cascade PPDU.
  • the at least one cascade PPDU may include a first cascade PPDU and a second cascade PPDU.
  • the data rate of the payload field included in the first cascade PPDU may be 62.5 kb / s or 250 kb / s.
  • the data rate of the payload field included in the second cascade PPDU may be 62.5 kb / s or 250 kb / s.
  • the size of the frame body field included in the first cascade PPDU may be 0, 8, or 16 bytes.
  • the size of the frame body field included in the second cascade PPDU may be 0, 8, or 16 bytes.
  • the frame control field may further include a type field.
  • the first and second cascade PPDUs are based on the type field, wake-up beacon, wake-up frame and wake-up vendor specific frame. It can be determined as one of the.
  • the receiving device may include a first STA, a second STA, and a third STA.
  • the first PPDU may be transmitted in the first subband for the first STA.
  • the first cascade PPDU may be transmitted in the second subband for the second STA.
  • the second cascade PPDU may be transmitted in the second subband for the third STA.
  • the sum of the length of the first sink field and the length of the first data rate may be equal to the sum of the length of the at least one cascade PPDU and the padding field length.
  • the first and second sequences may be set to a 13 length sequence or a 7 length sequence based on the first data rate and the second data rate.
  • the first subband and the second subband may be a 20 MHz band.
  • the IFFT may be a 64 point IFFT.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Computer Security & Cryptography (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

L'invention concerne un procédé et un dispositif d'envoi d'un paquet de réveil à un système de LAN sans fil. En particulier, un dispositif d'émission génère un paquet de réveil par l'application d'un procédé OOK. Le dispositif d'émission envoie le paquet de réveil à un dispositif de réception par l'intermédiaire d'une bande large. Le paquet de réveil comprend une première PPDU et une seconde PPDU. La première PPDU comprend un premier champ d'absorption et un premier champ de charge utile présentant un premier débit de données. La seconde PPDU comprend au moins une PPDU de cascade et un champ de remplissage. La ou les PPDU de cascade comprennent un second champ d'absorption et un second champ de charge utile présentant un second débit de données. La ou les PPDU de cascade sont une PPDU qui est émise de façon continue de telle façon que la longueur de la seconde PPDU concorde avec la longueur de la première PPDU.
PCT/KR2019/003633 2018-03-28 2019-03-28 Procédé et dispositif d'émission d'un paquet de réveil dans un système de lan sans fil Ceased WO2019190221A1 (fr)

Applications Claiming Priority (8)

Application Number Priority Date Filing Date Title
KR20180035843 2018-03-28
KR10-2018-0035843 2018-03-28
KR20180038547 2018-04-03
KR10-2018-0038546 2018-04-03
KR10-2018-0038547 2018-04-03
KR20180038546 2018-04-03
KR10-2018-0045460 2018-04-19
KR20180045460 2018-04-19

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WO2019190221A1 true WO2019190221A1 (fr) 2019-10-03

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20150044921A (ko) * 2012-08-17 2015-04-27 퀄컴 인코포레이티드 Wan을 위한 저전력 웨이크업 신호 및 동작들을 위한 시스템들 및 방법들
WO2017164687A1 (fr) * 2016-03-25 2017-09-28 엘지전자 주식회사 Procédé de gestion de puissance dans un système lan sans fil et terminal sans fil l'utilisant
US20180077641A1 (en) * 2016-09-09 2018-03-15 Futurewei Technologies, Inc. System and Method for Transmitting a Wake-up Packet

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20150044921A (ko) * 2012-08-17 2015-04-27 퀄컴 인코포레이티드 Wan을 위한 저전력 웨이크업 신호 및 동작들을 위한 시스템들 및 방법들
WO2017164687A1 (fr) * 2016-03-25 2017-09-28 엘지전자 주식회사 Procédé de gestion de puissance dans un système lan sans fil et terminal sans fil l'utilisant
US20180077641A1 (en) * 2016-09-09 2018-03-15 Futurewei Technologies, Inc. System and Method for Transmitting a Wake-up Packet

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STEVE SHELLHAMMER: "Proposed Draft WUR PHY Specification", IEEE 802.11-18/0152R5, 18 January 2018 (2018-01-18), XP055640463 *
SUNG-HYUN: "WUP CCA Problem", IEEE 802.11-17/1426R1, 12 September 2017 (2017-09-12), XP055640469 *

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