WO2020017929A1 - Procédé et appareil de transmission de paquet de réveil dans un système lan sans fil - Google Patents

Procédé et appareil de transmission de paquet de réveil dans un système lan sans fil Download PDF

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Publication number
WO2020017929A1
WO2020017929A1 PCT/KR2019/008961 KR2019008961W WO2020017929A1 WO 2020017929 A1 WO2020017929 A1 WO 2020017929A1 KR 2019008961 W KR2019008961 W KR 2019008961W WO 2020017929 A1 WO2020017929 A1 WO 2020017929A1
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Prior art keywords
wur
length
field
signal
bit
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PCT/KR2019/008961
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English (en)
Korean (ko)
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박은성
김정기
임동국
최진수
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엘지전자 주식회사
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00—Baseband systems
    • H04L25/38—Synchronous or start-stop systems, e.g. for Baudot code
    • H04L25/40—Transmitting circuits; Receiving circuits
    • H04L25/49—Transmitting circuits; Receiving circuits using code conversion at the transmitter; using predistortion; using insertion of idle bits for obtaining a desired frequency spectrum; using three or more amplitude levels ; Baseband coding techniques specific to data transmission systems
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/02—Amplitude-modulated carrier systems, e.g. using on-off keying; Single sideband or vestigial sideband modulation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
    • H04W52/02—Power saving arrangements
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
    • Y02D30/00—Reducing energy consumption in communication networks
    • Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks

Definitions

  • the present disclosure relates to a technique for performing low power communication in a WLAN system, and more particularly, to a method and apparatus for transmitting a wake-up packet by applying a OOK scheme in a WLAN system.
  • next-generation WLANs 1) enhancements to the Institute of Electronic and Electronics Engineers (IEEE) 802.11 physical layer (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 Electronic and Electronics Engineers
  • PHY physical layer
  • MAC medium access control
  • next-generation WLAN The environment mainly considered in next-generation WLAN is a dense environment with many access points and STAs, 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.
  • 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.
  • the transmission of a WUR PPDU (or a WUR packet) through a broadband may be regarded as a WUR PPDU applied in a frequency division multiplexing access (FDMA) scheme in a 20 MHz band within a wide bandwidth. Therefore, this embodiment can be said that WUR FDMA is applied.
  • FDMA frequency division multiplexing access
  • the length of the WUR packet may be different for each subchannel.
  • a third-party STA non-WUR STA irrelevant to the WUR transmission determines that the WUR packet transmission is terminated early or idle for a specific subchannel without the WUR packet, and performs channel access to perform WUR FDMA transmission. Can cause interference.
  • a padding bit is added to prevent interference by adjusting the lengths of WUR packets to which WUR FDMA transmitted on each subchannel is equal to each other. Accordingly, the TXTIME and L-LENGTH values are changed accordingly. Suggest.
  • the on-symbol may correspond to a symbol on which an on signal having an actual power value is transmitted.
  • the off-symbol may correspond to a symbol in which an off signal having no actual power value is transmitted.
  • the transmitter generates a WUR packet by applying an OOK (On-Off Keying) method.
  • the transmitter transmits the WUR packet to the receiver.
  • the WUR packet includes a legacy-signal (L-SIG) field, a first WUR signal field, and a second WUR signal field.
  • the WUR packet can be largely divided into a WUR signal part to which legacy preamble and FDMA are applied.
  • the legacy preamble may be duplicated in units of 20 MHz subchannels.
  • the legacy preamble may include a Legacy-Short Training Field (L-STF), a Legacy-Long Training Field (L-LTF), the L-SIG field, Binary Phase Shift Keying (BPSK) Mark1, and BPSK Mark2.
  • the WUR signal part may include the first and second WUR signal fields.
  • the first WUR signal field is transmitted on a first subchannel, and includes a first sync field and a first data field.
  • the second WUR signal field is transmitted on a second subchannel and includes a second sink field and a second data field.
  • the L-SIG field includes an L-LENGTH (Legacy-LENGTH) value that is a length of the longest WUR signal field among the first and second WUR signal fields. As described later, if the first WUR signal field is the longest among the WUR signal fields transmitted in each subchannel, the L-LENGTH value may be the length of the first WUR signal field.
  • L-LENGTH Legacy-LENGTH
  • a padding bit is inserted after the second WUR signal field based on the L-LENGTH value.
  • the padding bits may be inserted in order to equalize the length of the WUR packet transmitted through each subchannel (here, to equalize the length of the first WUR signal field).
  • a TXTIME value which is a transmission time of the WUR packet.
  • the TXTIME value is changed by reducing the number of OOK symbols included in the first data field by one.
  • the transmitter Since the last symbol of the first WUR signal field is an off symbol, the transmitter does not need to adjust the length from the other subchannel to the last off symbol. Since the LDR is applied to the first WUR signal field, the last symbol (off symbol) has a length of 4 us. That is, the transmitter can change the TXTIME value by subtracting the length of 4us. Reducing the number of OOK symbols by one means that the length of the last 4us off symbol is excluded.
  • the L-LENGTH value may be changed based on the changed TXTIME value.
  • the changed L-LENGTH value may include information about a length excluding the last symbol in the first WUR signal field.
  • the existing TXTIME value may be obtained through the following equation.
  • the changed TXTIME value may be obtained by replacing T Sym, iBW * N Sym, iBW , which is the last part of the equation, with T Sym, iBW * (N Sym, iBW- 1).
  • the existing L-LENGTH value may be obtained through the following equation.
  • the non-WUR STA may decode the changed L-LENGTH value and determine the length of the WUR packet up to the portion excluding the last off symbol 4us. Accordingly, the third party receiver may give an opportunity to transmit data by performing channel access more quickly (as soon as the last off symbol).
  • the first and second data fields may consist of an on symbol or an off symbol.
  • the on symbol may be generated by an On-Waveform Generator (On-WG) when the Manchester encoded bit is one.
  • the off symbol may be generated by Off-WG when the Manchester encoded bit is zero.
  • the Manchester encoded bit may be generated by having a source bit encoded by a Manchester based encoder. That is, the above-described embodiment is a first embodiment in which padding bits are inserted in a source bit stage before input to a Manchester-based encoder and a second embodiment in which padding bits are inserted in an encoded bit stage after being output by a Manchester-based encoder. Can be divided into The following description refers only to the first embodiment.
  • the Manchester encoded bit When LDR is applied to the first and second data fields, if the source bit is 0, the Manchester encoded bit may be 1010. If the source bit is 1, the Manchester encoded bit may be 0101. One Manchester encoded bit may have a length of 4 us.
  • the padding bit when the padding bit has a length of 32us, the padding bit is a Manchester encoded bit generated by the Manchester based encoder by adding an input padding bit to the source bit. If the input padding bit is 11, the padding bit may be 01010101. If the input padding bit is 01, the padding bit may be 10100101. Since the length of one Manchester encoded bit is 4us, the padding bit may have a length of 32us (4us * 8).
  • High data rate if the source bit is 0, the Manchester encoded bit is 10; if the source bit is 1, the Manchester encoded bit is 01 Can be.
  • One Manchester encoded bit may have a length of 2us.
  • the padding bit when the padding bit has a length of 32us, the padding bit is a Manchester encoded bit generated by the Manchester based encoder by adding an input padding bit to the source bit. If the input padding bit is 11111111, the padding bit may be 01010101010101. Since the length of one Manchester encoded bit is 2us, the padding bit may have a length of 32us (2us * 16).
  • the WUR packet may further include a third WUR signal field and a fourth WUR signal field.
  • the third WUR signal field is transmitted on a third subchannel, and may include a third sync field and a third data field.
  • the fourth WUR signal field is transmitted in a fourth subchannel and may include a fourth sync field and a fourth data field.
  • the padding bit may be inserted after the third WUR signal field based on the L-LENGTH value.
  • the padding bit may be inserted after the fourth WUR signal field based on the L-LENGTH value.
  • the padding bits are also inserted in the third and fourth subchannels in order to equalize the length of the WUR packet transmitted through each subchannel (here, to equalize the length of the first WUR signal field). Can be.
  • Each of the first to fourth subchannels may be a 20 MHz subchannel.
  • the receiving device may include first to fourth receiving devices.
  • the first receiving device may decode the first WUR signal field transmitted in the first subchannel.
  • the second receiver may decode the second WUR signal field transmitted on the second subchannel.
  • the third receiver may decode the third WUR signal field transmitted in the third subchannel.
  • the fourth receiver may decode the fourth WUR signal field transmitted on the fourth subchannel.
  • the on symbol may be generated by inserting a sequence into 13 consecutive subcarriers in the first, second, third or fourth subchannels and performing an inverse fast fourier transform (IFFT).
  • the sequence may be set to a 13 length sequence, a 7 length sequence, or the like based on the data rate.
  • the IFFT may be a 64 point IFFT.
  • the first to fourth WUR signal fields may include a MAC header, a frame body field, and a frame check sequence (FCS) field.
  • the length of the MAC header may be 4 bytes.
  • the length of the frame body field may be 0, 8 or 16 bytes.
  • the length of the FCS field may be 2 bytes.
  • 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 by using an envelope detector, thereby reducing power consumed in decoding.
  • the wakeup packet is configured and transmitted by applying a OOK modulation scheme to the transmitter, thereby reducing power consumption by using an envelope detector during wakeup decoding at the receiver. Therefore, the receiver may decode the wakeup packet with the minimum power.
  • the non-WUR STA decodes the changed L-LENGTH value to determine the length of the WUR packet up to the portion excluding the last off symbol, so that the third-party receiver is faster. It can give you the opportunity to send data.
  • 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 illustrates 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 shows an example of a wakeup packet structure transmitted through the 40 MHz band according to the present embodiment.
  • FIG. 18 illustrates an example of a wakeup packet structure transmitted through an 80 MHz band according to the present embodiment.
  • FIG. 19 is a block diagram of a WUR signal generator for generating a WUR data field according to the present embodiment.
  • 20 is a block diagram of a WUR signal generator for generating a WUR data field for WUR FDMA transmission according to the present embodiment.
  • 21 shows an example of an L-SIG structure in a legacy preamble according to the present embodiment.
  • FIG. 22 is a diagram illustrating timing boundaries for a WUR basic PPDU according to the present embodiment.
  • 23 is a flowchart illustrating a procedure of transmitting a WUR packet by applying the OOK method according to the present embodiment.
  • 24 is a flowchart illustrating a procedure of receiving a WUR packet by applying the OOK method according to the present embodiment.
  • 25 is a view for explaining an apparatus for implementing the method as described above.
  • Figure 26 shows a more detailed wireless device implementing an embodiment of the present invention.
  • 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 STAs 103-1 and 105-2 that can be coupled 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) to another network (eg, 802.X).
  • IEEE 802.11 IEEE 802.11
  • 802.X another network
  • 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 are not allowed to access a distributed system, and thus are self-contained. network).
  • a STA is any functional medium that includes medium access control (MAC) and physical layer interface to a wireless medium that is compliant with the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard. 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
  • a 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, 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 is 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 (FFTs), 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 a variety of techniques to transmit 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 that support the operation of an IEEE 802.11-based wireless LAN (WLAN).
  • the MAC layer utilizes protocols that coordinate access to shared radios and improve communications over wireless media, allowing 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).
  • NIC wireless network card
  • STA wireless device or station
  • Manage and maintain communication between APs manage and maintain communication between APs.
  • IEEE 802.11ax is a 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 for 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 turn off the power to 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 data reception and the communication block is turned on only when there is data to wake up, 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. That is, it does not include a transmitter.
  • 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).
  • a main radio such as Wi-Fi, Bluetooth® radio, or Bluetooth® Radio (BLE).
  • BLE Bluetooth® Radio
  • 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 using 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 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 example 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 configured 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 may know the end of the packet through the L-SIG field in the legacy preamble 610.
  • BPSK-modulated symbol after adding a BPSK-modulated symbol after the L-SIG, false alarms of 802.11n terminals 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 receiving apparatus that receives the wakeup packet 600 or an identifier of the receiving apparatus.
  • 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.
  • information in the form of a binary sequence having 1 or 0 as a bit value is represented.
  • communication in the OOK modulation method can be performed. That is, the OOK modulation scheme may perform communication in consideration of the bit values of the binary sequence information. For example, when the light emitting diode is used for visible light communication, the light emitting diode is turned on when the bit value constituting the binary sequence information is 1, and the light emitting diode is turned off when the bit value is 0. The light emitting diode can be made to blink.
  • the receiver receives and restores data transmitted in the form of visible light, thereby enabling communication using visible light.
  • the human eye cannot perceive the blinking of the light emitting diode, 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, and when the bit value is 0, the transmitter is turned off, the symbol is turned on at 6 bit values out of 10 bit values. ) do. Therefore, when the symbol is turned on in all 10 bit values, if the power consumption is 100%, the power consumption is 60% according to the duty cycle of FIG. 8.
  • the power consumption of the transmitter is determined according to the ratio of 1 and 0 constituting the binary sequence information.
  • the ratio of 1 and 0, which constitutes information in binary sequence form must also be maintained.
  • the lighting must be maintained at a specific luminance value desired by people, and thus the ratio of 1 and 0 constituting the binary sequence information must also be maintained.
  • the receiver is mainly a wake-up receiver (WUR)
  • WUR wake-up receiver
  • OOK the transmission power is not important.
  • the main reason for using OOK is that it consumes very little power 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 may generate a sequence having 64 bits by applying a 64-point IFFT as in the existing 802.11.
  • the transmitter must 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 in 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 3.2us symbol may be generated, and if 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 62.5 Kbps (16us).
  • each signal having a length of K in the 20 MHz band may be transmitted in K consecutive subcarriers of 64 subcarriers in total. 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.
  • the Manchester coding technique refers to 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 based on the transition point of 1 ⁇ 0 or 0 ⁇ 1 and recovers the data, and then transitions to 1 ⁇ 0 or 0 ⁇ 1.
  • the clock is recovered by recognizing the transition point as the clock transition point.
  • the symbol when the symbol is divided by 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 to be transmitted 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. The data is then recovered 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.
  • CP Cyclic Prefix or Guard Interval
  • signal part representing actual information.
  • the basic WUR symbol may be represented as CP + 3.2us. That is, one bit is represented by using a symbol having the same length as the existing Wi-Fi.
  • the transmitter applies IFFT to all available subcarriers (eg, 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.
  • the CP may be used by adopting a specific length from the back of the information signal 3.2us immediately behind. At this time, the 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 the guard interval of the transmission signal is 3.2us.
  • 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 Manchester coded symbol. 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.
  • 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 particular sequence to K consecutive subcarriers of 64 subcarriers (eg, 33-floor (K / 2): 33 + ceil (K / 2) -1) and performs IFFT.
  • the signal of 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, the off-symbol can be contiguous, for example, the sequence is 100001, etc., but if Manchester coding is used, the off-symbol cannot be contiguous to 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.
  • the 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, the 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.
  • a symbol repetition technique is applied to the wakeup payload 724.
  • the symbol repetition technique refers to 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 phases of the signal from the transmitter and 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 obtained and determined as information 1 (1 1) if it is equal to or greater than the threshold value, and may be determined as information 0 (0 0) if 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.
  • This may be a sequence of symbols reconstructed by an interleaver.
  • 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.
  • information 0 and information 1 may be repeatedly represented by the same symbol n times.
  • 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.
  • n symbols may be represented by dividing the number of symbols 1 (symbol including information 1) and the number of symbols 0 (symbol including information 0).
  • the interleaver may be applied in units of packets and specific symbols.
  • the reception 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. Therefore, option 2 may be preferred because 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 successively consists of nm 0 (OFF) or 1 (ON) redundant symbols after or before. can do.
  • applying a code rate of 3/4 to the information 010 may be 1,010 or 010,1 or 0,010 or 010,0.
  • a code rate of 1/2 or less may be desirable to apply.
  • the order of symbols may 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).
  • n 2 information signals (symbols).
  • IFFT is taken and 3.2us of information is used. Form a signal (symbol).
  • a 3.2us off signal can be generated by applying all coefficients to zero.
  • the CP may be used by adopting a specific length from the back of the information signal 3.2us immediately behind. At this time, the 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 (CP + 3.2us) including CP or CP + n (3.2us) may indicate one 1-bit information. That is, in 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 (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.
  • the CP may be used by adopting a specific length from the back of the information signal 3.2us immediately behind. At this time, the 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 (e.g., 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.
  • the CP may be used by adopting a specific length from the back of the information signal 3.2us immediately behind. At this time, the 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.
  • the CP may be used by adopting a specific length from the back of the information signal 3.2us immediately behind. At this time, the 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).
  • n 2
  • a specific sequence is applied to all available subcarriers (for example, 13), and the remaining coefficients of 0 are applied.
  • 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.
  • the 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, the 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 pieces (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 the (CP + 1.6us) on signal, and the 1.6us off signal is the (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), and if the fourth iteration is 62.5Kbps (16us), 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 the symbol reduction technique is used to represent one bit, and a specific sequence is applied to every available subcarrier (for example, thirteen) in m units, and the remaining coefficients are set to zero. do.
  • a specific sequence is applied to every available subcarrier (for example, thirteen) in m units, and the remaining coefficients are set to zero. do.
  • IFFT is applied to the subcarrier to which the specific sequence is applied, a 3.2us signal having a 3.2us / m period is generated. Take one of these and map it to the 3.2us / m information signal (information 1).
  • 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 of the 3.2us / m on signal and the 3.2us / m off signal, respectively.
  • the 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 the guard interval of the transmission signal is 3.2us.
  • 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 using the characteristics of Manchester coding is also used.
  • 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 a symbol 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 specific 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.
  • 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 the information 0 is generated. Can be configured.
  • the information 0 may be configured as 01 and the 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 + 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 CP may indicate one 1-bit information.
  • the length of a symbol carrying one piece of information becomes CP + 0.4us.
  • the 0.5us off signal or the 0.5us on signal consists 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 illustrates 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 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.
  • information 0 may form a 2us on signal by taking half of the 4us symbol.
  • 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 first half of the 4us symbol does not transmit any information and thus can configure a 2us off signal.
  • 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 a 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 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 a 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 is a Length / Misc subfield indicating 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 a payload of a 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 the frame format 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 signal transmitted to wake the primary radio may be transmitted using 4 MHz within 20 MHz bandwidth or a wake up signal using FDMA to a plurality of STAs using multiple channels.
  • the WUR-sync field of FIG. 16 may be called a WUR-preamble.
  • 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-preamble and a WUR-payload 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 WUR part may be transmitted using narrow bandwidth using some of the available tones in the bandwidth (BW) in which the L-part is transmitted, and may be transmitted using the 4 MHz BW for transmitting the WUR signal.
  • BW bandwidth
  • the number of available tones in terms of frequency according to BW is, for example, 13 when OFDM numerology is used, and the length of the frequency sequence for constructing the WUR ON symbol is equal to the number of available tones.
  • a WUR PPDU is formed by adding OFDM symbols BPSK-modulated to BPSK (BPSK-Mark 1 and BPSK-Mark 2) after L-part.
  • the BPSK-Mark1 field and the BPSK-Mark 2 field are repetitions of the L-SIG field and are used to spoof a HT (non-WUR) device from false packet type detection.
  • the WUR PPDU may be transmitted using wide bandwidth differently from FIG. 16.
  • the WUR PPDU transmitted using the wide bandwidth e.g. 40 MHz / 80 MHz / 160 MHz (not shown)
  • 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
  • the WUR FDMA PPDU may be sent to a multi-user.
  • FIG 17 shows an example of a wakeup packet structure transmitted through the 40 MHz band according to the present embodiment.
  • FIG. 18 illustrates an example of a wakeup packet structure transmitted through an 80 MHz band according to the present embodiment.
  • the legacy preamble, BPSK mark 1 and BPSK mark 2 which are non WUR portions, are duplication in 20 MHz units.
  • 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 L-SIG included in the WUR PPDU is composed of the fields shown in FIG. 21, and when the WUR PPDU is transmitted, the PAPR of the L-SIG varies depending on the length field (L-Length field) in the L-SIG.
  • 17 is a structure of a WUR FDMA PPDU formed using a 40 MHz bandwidth and can be transmitted to two users or two groups using each 20 MHz sub-channel.
  • 18 is a structure of a WUR FDMA PPDU formed using 80 MHz bandwidth and can be transmitted to 4 users or 4 groups using each 20 MHz sub-channel.
  • each sub-channel may be configured with a different data rate (ie, specific sub-channels may be HDR used in a FDMA PPDU and LDR may be used for a specific sub-channel).
  • the length of the frame body may be different for each sub-channel. Therefore, the WUR signal length may be different for each sub-channel, and in this case, another STA (which may be an OBSS STA or an STA in the BSS) irrelevant to the WUR transmission may say that the 40 or 80 MHz channel as well as its primary 20 MHz channel is idle. Since the probability of judgment is increased and the channel can be accessed, it may eventually interfere with transmission and reception of a WUR FDMA packet. Therefore, it is essential to pad the packet length of each sub-channel in the WUR FDMA packet to have the same length. 17 and 18 show a WUR FDMA PPDU structure when padding is inserted.
  • padding is a padding bit to align with the length indicated by the L-Length field of the L-SIG if the duration of the WUR transmission in the non-punctured 20 MHz sub-channel is shorter than the L-Length. Create and insert However, padding does not apply to punctured 20 MHz sub-channels.
  • FIG. 19 is a block diagram of a WUR signal generator for generating a WUR data field according to the present embodiment.
  • the WUR data field is generated using an on waveform generator (On-WG) and an off waveform generator (Off-WG).
  • information bits are mapped to bits coded by a WUR encoder. Each coded bit is used to switch between On-WG and Off-WG.
  • On / Off-WG for the HDR WUR data field is as follows.
  • an MC-OOK On symbol with a duration of 2 us should be configured by On-WG using 13 center subcarriers sampled at 20 MHz and applied a 64-point IDFT.
  • an MC-OOK Off symbol with a duration of 2 us should be configured to 0 for 2 us by Off-WG.
  • On / Off-WG for the LDR WUR data field is as follows.
  • an MC-OOK On symbol with a duration of 4 us shall be configured by On-WG using 13 center subcarriers sampled at 20 MHz and applied a 64-point IDFT.
  • the MC-OOK Off symbol with a duration of 2 us should be configured to 0 for 4 us by Off-WG.
  • 20 is a block diagram of a WUR signal generator for generating a WUR data field for WUR FDMA transmission according to the present embodiment.
  • the MC-OOK On symbol for the 20 MHz WUR waveform is generated by the WUR signal generator as shown in FIG. 19, whereas the 40 MHz or 80 MHz WUR FDMA PPDU should be generated by multiplexing multiple 20 MHz waveforms in the WUR signal generator as shown in FIG. 20.
  • 21 shows an example of an L-SIG structure in a legacy preamble according to the present embodiment.
  • the RATE field is 4 bits
  • the Reserved field is 1 bit
  • the Length field is 12 bits (up to 4095)
  • the Parity bit field is 1 bit
  • the Tail bit is 6 bits.
  • rate is basically considered 6Mbps.
  • the length field indicating the length of the WUR PPDU may be calculated in consideration of the following lengths and parameters.
  • the length of WUR preamble consists of the following lengths according to the data rate.
  • WUR payload ie MAC Header + Frame body + FCS
  • the length of the WUR PPDU may be calculated using 1, 2, and 3, and at this time, it is possible to calculate how many symbols the WUR PPDU consists of based on a 4us symbol.
  • the calculated Number of symbols can be obtained using the formula below. In particular, the number of symbols can be obtained using a length field (12 bits) transmitted through the L-SIG.
  • the L_LENGTH set in the L-SIG may be set to the longest packet length among the sub-channels in which the WUR FDMA PPDU is transmitted.
  • the following is a configuration method of TXTIME and L_LENGTH.
  • TXTIME of the WUR PPDU can be obtained using the following equation.
  • T L - STF, T L - LTF, T L - SIG, T BPSK - Mark1, T BPSK - Mark2, T WUR -Sync Sym and T can be defined in the following table.
  • N Sym is the number of MC-OOK symbols included in the WUR data field.
  • the number of MC-OOK symbols is a function of the length (WUR_MPDU_LENGTH) and the N SPDB of the WUR MAC frame in the WUR data field, and can be calculated as follows.
  • the N SPDB may be defined in the table below.
  • the value of the PSDU_LENGTH parameter may be calculated as follows.
  • the RATE field of the L-SIG shall be set to a value indicating 6 MB / s in the 20 MHz channel.
  • the Length field L_LENGTH included in the L-SIG may be calculated as follows.
  • the values of TXTIME and PSDU_LENGTH for each WUR transmission in the 20 MHz sub-channel can be calculated according to the longest WUR transmission of all 20 MHz sub-channels.
  • the value of the TXTIME parameter for WUR FDMA transmission can be calculated as follows.
  • ⁇ 20MHz is a set of unpunctured 20MHz sub-channels.
  • i BW is the index of the 20 MHz sub-channel, and 0 ⁇ i BW ⁇ N 20 MHz .
  • N 20MHz is the number of 20MHz sub-cannels in the bandwidth indicated by dot11CurrentChannelWidth.
  • T WUR - Sync, iBW, T sym, iBW, T and T WUR -Sync Sym are defined in Table 19 for the sub-channel i BW 20MHz.
  • N sym, iBW is the number of MC-OOK symbols included in the WUR-data field for 20MHz sub-channel i BW .
  • the number of MC-OOK symbols is a function of the length of the WUR MAC frame (WUR_MPDU_LENGTH) and the N SPDB in the WUR data field for 20 MHz sub-channel i BW and can be calculated as shown in Equation 3 above.
  • the padding waveform should be generated by repeating the MC-OOK waveform of HDR information bit 1.
  • a symbol randomizer should be used in the padding field contiguous from the WUR data field.
  • the number of padding HDR bits can be calculated as follows.
  • FIG. 22 is a diagram illustrating timing boundaries for a WUR basic PPDU according to the present embodiment.
  • the transmitted RF signal is obtained by up-converting a complex baseband signal composed of several fields. Timing boundaries for the various fields are shown in FIG. 22.
  • N WUR- Sync is the number of MC-OOK symbols in the WUR sync field and is defined in Table 20 above.
  • the timing offset value of FIG. 22 may be given as follows.
  • the WUR sync field and the WUR data field are each composed of MC-OOK symbols.
  • padding can be inserted so that packet length is equal to L_LENGTH.
  • Two padding methods are proposed as follows.
  • 19 is a block diagram for waveform generation of a WUR data part.
  • the source bit is applied to Manchester based encoder to generate Manchester encoded bit. If Manchester encoded bit is 1, On-symbol is formed by On waveform generator. If 0, Off-symbol is formed according to Off waveform generator. 19 simply illustrates a WUR encoder. As described above, if the WUR encoder is a Manchester based encoder, a Manchester encoded bit may be generated.
  • the following shows Manchester encoded bits according to LDR source bits and has a length of 4us per encoded bit. That is, one input bit (or information bit) has a length of 16 us.
  • the following shows Manchester encoded bits according to source bits in HDR and has a length of 2us per encoded bit. That is, one input bit (or information bit) has a length of 4 us.
  • a padding bit may be inserted into a source bit. For example, suppose L_LENGTH is calculated and 64 T is obtained as T Sym * N Sym . At this time, if the source bit of a specific sub-channel is 2 bits and LDR is used, the total T Sym * N Sym will be 32us. Accordingly, 32us of padding is required in the specific sub-channel to match the length of L-LEGNTH, and 2bits (padding bits in the source bit end) may be inserted into the source bit to generate 32us of padding bit. .
  • Padding bit may be inserted both 0 or 1. That is, one of 11, 10, 01, and 00 may be inserted as a padding bit in the source bit. However, when 10 or 00 is inserted as a padding bit, the last encoded bit is 0, so the last 4us is composed of off-symbols. This means that padding signals for L_LENGTH are not inserted. Therefore, 1 may be inserted as the last padding bit. For example, if a padding bit of 11 or 01 is inserted into a source bit in a specific sub-channel using LDR, the last 4us symbol is composed of On-symbol because the encoded bit is 0101 or 1001 and the last encoded bit is 1. .
  • padding may always be inserted in HDR regardless of the WUR data rate and the information bit may always be 1 (or 0). That is, in the above example, when 32us of padding is required in a specific sub-channel, a padding bit using 8 bits (for example, 11111111) HDR may be inserted into the source terminal regardless of the WUR data rate. Specifically, if 11111111 padding bit is inserted into the source bit in a specific sub-channel using HDR, the encoded bit becomes 0101010101010101 so that a total of 32us of padding is inserted.
  • the symbol consists of On-symbols).
  • Equation (7) is the number of padding bits to be inserted when using the padding bits of HDR.
  • the last 4us or 2us may be off-symbol (when the LDR or HDR or source bit is 0, the last symbol is always off-symbol). ). In this case, it may not be necessary to set the last 4us or 2us padding to On-symbol to set L_LENGTH in other sub-channels. In this case, 0 may be inserted as the last padding bit of the source bit in another sub-channel. For example, when padding of HDR is attached, all padding bits may be 1 and only the last bit may be 0. For example, if a padding bit using 8-bit HDR is inserted into the source terminal, the 8-bit may be configured as 11111110.
  • the last 4us may be off-symbol.
  • L_LENGTH can be set to the length of the sub-channel with the longest packet length, except for the last off-symbol, when the last source bit is 0.
  • the OOK symbol length is 2us and the L_LENGTH length is calculated in units of 4us, so even if the last OOK symbol of HDR is Off symbol, the length including the last Off-symbol is expressed as L_LENGTH. You can only set it.
  • L_LENGTH can be set in this way only for LDR with OOK symbol length of 4us. That is, in the WUR FDMA PPDU, if the sub-channel with the longest packet length uses LDR and the last source bit is 0, 4us, the length of the last off-symbol, can be excluded from L_LENGTH.
  • the L_LENGTH formula is set as follows. It can be set equally to L-SIG of all sub-channels.
  • the padding bit when the padding bit is inserted using HDR, the TXTIME calculated by Equation 5 may be used and the padding bit may be inserted using Equation 7.
  • N Sym It can be set as follows.
  • the last padding bit in the source bit of another sub-channel may be set to one.
  • other devices have the disadvantage of having a later transmission opportunity.
  • the last 4us can be set to a different value if the last 4us is off-symbol. If the TXTIME is calculated in consideration of the last off-symbol, Equation 6 The part can be subtracted considering 4us off-symbol. That is, in the sub-channel using LDR and the last off-symbol, -4us can be added to the expression inside the curly brace of max. Alternatively, the last part of the equation may be replaced by T Sym, iBW * (N Sym, iBW- 1).
  • N Sym 8 * WUR_MPDU_LENGTH * N SPDB -1
  • the L_LENGTH value is set to the same as the above Equation 5 in L-SIG of all sub-channels using the following L_LENGTH equation, and other devices read it and determine the packet length only to the part except the last off symbol 4us. It can give them a faster transmission opportunity.
  • L_LENGTH expression should be converted as follows.
  • Ceil (a) means to raise.
  • the padding bit can be inserted into the Manchester encoded bit and can be inserted as only 1, or both 0 or 1 can be inserted. However, the padding bit of 0 can be inserted in succession. By increasing the channel access probability, interference may be affected. Therefore, it is preferable that all padding bits inserted in the Manchester encoded bit are 1, and in particular, it may be important to set the last padding bit to 1 to have the same length as L_LENGTH. For example, suppose that the result of calculating L_LENGTH is 64us as T Sym * N Sym . At this time, if the source bit of one sub-channel is 2 bits and LDR is used, it generates 8 bits of Manchester encoded bit and has a total length of 32 us.
  • 8-bit padding bit is required to match the length of L_LENGTH in the corresponding sub-channel, and 8-bit padding bit can be inserted into Manchester encoded bit. Consecutive zero paddings are undesirable and all padding bits of one may be desirable. In particular, the last 8th padding bit may be inserted with 1 as necessary. For example, 11111111, which is an 8-bit padding bit, may be inserted into a Manchester encoded bit (when the WUR encoder of FIG. 19 is a Manchester based encoder).
  • a padding bit having a length of 2 us may be inserted regardless of the WUR data rate. That is, in the above example, when 32us padding is required to match the length of L_LENGTH in the sub-channel, a padding bit having a length of 2us of 16 bits may be inserted regardless of the WUR data rate.
  • the last 4us or 2us may be off-symbol (the last symbol is always off-symbol when LDR or HDR or source bit is 0). .
  • the padding bit of the Manchester encoded bit may be set in consideration of this length.
  • the sub-channel having the longest packet length uses LDR and the last source bit is 0 (that is, the last 4us is off-symbol).
  • a specific sub-channel using LDR can be set to 1 in the last padding bit and 0 in the last padding bit (4us On-symbol + 4us Off-symbol, and finally 4us Off-symbol).
  • Another specific sub-channel using HDR can be set to the last to third padding bits to 1 and the last to second and last padding bits to 0 (2us On-symbol + 2us Off-symbol + 2us Off-symbol). , 4us Off-symbol at the end).
  • L_LENGTH (or TXTIME) may be set only as long as the last source bit of the sub-channel having the longest packet length is 0 except the last off-symbol. This may be limited only when the sub-channel with the longest packet length uses LDR, as mentioned in A. above. In this case, the last padding bit in the Manchester encoded bit of another sub-channel may be set to 1.
  • the padding bit of 1 may be added to the Manchester encoded bit so that it ends in On-symbol. If the sub-channel with the longest packet length uses LDR and the last source bit is 0, a padding bit of 1 can be added to the Manchester encoded bit (4us on-symbol can be made). If the sub-channel with the longest packet length uses HDR and the last source bit is 0, two padding bits of 1 can be added to the Manchester encoded bit (2us On-symbol + 2us On-symbol can be made). ). Alternatively, the first padding bit may be set to zero. The reason for adding two is to match the 4us unit. In this case, the L_LENGTH equation is set as follows and this value can be set equally in L-SIG of all sub-channels.
  • TXTIME may be obtained using the L-LENGTH value changed in Equation 5.
  • Equation 6 In the sub-channel where the end is off-symbol in max brace of, it can be modified by inserting + 4us. Alternatively, in the sub-channel using the LDR whose last symbol is Off-symbol, the last part of Equation (Equation 6) may be replaced with the following Equation.
  • the last part of the equation may be replaced by the following equation.
  • L_LENGTH according to the existing equation (Equation 5) is set in the L-SIG of all sub-channels, and the last padding bit in the Manchester encoded bit of the sub-channel requiring padding may be set to 1.
  • Equations 2 to 5 we propose the calculation of TXTIME and L_LENGTH in single 20MHz transmission. Equations such as TXTIME / L_LENGTH including the last off-symbol are as shown in Equations 2 to 5 above.
  • 23 is a flowchart illustrating a procedure of transmitting a WUR packet by applying the OOK method according to the present embodiment.
  • FIG. 23 An example of FIG. 23 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.
  • the transmission of a WUR PPDU (or a WUR packet) through a broadband may be regarded as a WUR PPDU applied in a frequency division multiplexing access (FDMA) scheme in a 20 MHz band within a wide bandwidth. Therefore, this embodiment can be said that WUR FDMA is applied.
  • FDMA frequency division multiplexing access
  • the length of the WUR packet may be different for each subchannel.
  • a third-party STA non-WUR STA irrelevant to the WUR transmission determines that the WUR packet transmission is terminated early or idle for a specific subchannel without the WUR packet, and performs channel access to perform WUR FDMA transmission. Can cause interference.
  • a padding bit is added to prevent interference by adjusting the lengths of WUR packets to which WUR FDMA transmitted on each subchannel is equal to each other. Accordingly, the TXTIME and L-LENGTH values are changed accordingly. Suggest.
  • the on-symbol may correspond to a symbol on which an on signal having an actual power value is transmitted.
  • the off-symbol may correspond to a symbol in which an off signal having no actual power value is transmitted.
  • the transmitter In operation S2310, the transmitter generates a WUR packet by applying an On-Off Keying (OOK) method.
  • OOK On-Off Keying
  • the transmitter transmits the WUR packet to the receiver.
  • the WUR packet includes a legacy-signal (L-SIG) field, a first WUR signal field, and a second WUR signal field.
  • the WUR packet can be largely divided into a WUR signal part to which legacy preamble and FDMA are applied.
  • the legacy preamble may be duplicated in units of 20 MHz subchannels.
  • the legacy preamble may include a Legacy-Short Training Field (L-STF), a Legacy-Long Training Field (L-LTF), the L-SIG field, Binary Phase Shift Keying (BPSK) Mark1, and BPSK Mark2.
  • the WUR signal part may include the first and second WUR signal fields.
  • the first WUR signal field is transmitted on a first subchannel, and includes a first sync field and a first data field.
  • the second WUR signal field is transmitted on a second subchannel and includes a second sink field and a second data field.
  • the L-SIG field includes an L-LENGTH (Legacy-LENGTH) value that is a length of the longest WUR signal field among the first and second WUR signal fields. As described later, if the first WUR signal field is the longest among the WUR signal fields transmitted in each subchannel, the L-LENGTH value may be the length of the first WUR signal field.
  • L-LENGTH Legacy-LENGTH
  • a padding bit is inserted after the second WUR signal field based on the L-LENGTH value.
  • the padding bits may be inserted in order to equalize the length of the WUR packet transmitted through each subchannel (here, to equalize the length of the first WUR signal field).
  • a TXTIME value which is a transmission time of the WUR packet.
  • the TXTIME value is changed by reducing the number of OOK symbols included in the first data field by one.
  • the transmitter Since the last symbol of the first WUR signal field is an off symbol, the transmitter does not need to adjust the length from the other subchannel to the last off symbol. Since the LDR is applied to the first WUR signal field, the last symbol (off symbol) has a length of 4 us. That is, the transmitter can change the TXTIME value by subtracting the length of 4us. Reducing the number of OOK symbols by one means that the length of the last 4us off symbol is excluded.
  • the L-LENGTH value may be changed based on the changed TXTIME value.
  • the changed L-LENGTH value may include information about a length excluding the last symbol in the first WUR signal field.
  • the existing TXTIME value may be obtained through the following equation.
  • the changed TXTIME value may be obtained by replacing T Sym, iBW * N Sym, iBW , which is the last part of the equation, with T Sym, iBW * (N Sym, iBW- 1).
  • the existing L-LENGTH value may be obtained through the following equation.
  • the non-WUR STA may decode the changed L-LENGTH value and determine the length of the WUR packet up to the portion excluding the last off symbol 4us. Accordingly, the third party receiver may give an opportunity to transmit data by performing channel access more quickly (as soon as the last off symbol).
  • the first and second data fields may consist of an on symbol or an off symbol.
  • the on symbol may be generated by an On-Waveform Generator (On-WG) when the Manchester encoded bit is one.
  • the off symbol may be generated by Off-WG when the Manchester encoded bit is zero.
  • the Manchester encoded bit may be generated by having a source bit encoded by a Manchester based encoder. That is, the above-described embodiment is a first embodiment in which padding bits are inserted in a source bit stage before input to a Manchester-based encoder and a second embodiment in which padding bits are inserted in an encoded bit stage after being output by a Manchester-based encoder. Can be divided into The following description refers only to the first embodiment.
  • the Manchester encoded bit When LDR is applied to the first and second data fields, if the source bit is 0, the Manchester encoded bit may be 1010. If the source bit is 1, the Manchester encoded bit may be 0101. One Manchester encoded bit may have a length of 4 us.
  • the padding bit when the padding bit has a length of 32us, the padding bit is a Manchester encoded bit generated by the Manchester based encoder by adding an input padding bit to the source bit. If the input padding bit is 11, the padding bit may be 01010101. If the input padding bit is 01, the padding bit may be 10100101. Since the length of one Manchester encoded bit is 4us, the padding bit may have a length of 32us (4us * 8).
  • High data rate if the source bit is 0, the Manchester encoded bit is 10; if the source bit is 1, the Manchester encoded bit is 01 Can be.
  • One Manchester encoded bit may have a length of 2us.
  • the padding bit when the padding bit has a length of 32us, the padding bit is a Manchester encoded bit generated by the Manchester based encoder by adding an input padding bit to the source bit. If the input padding bit is 11111111, the padding bit may be 01010101010101. Since the length of one Manchester encoded bit is 2us, the padding bit may have a length of 32us (2us * 16).
  • the WUR packet may further include a third WUR signal field and a fourth WUR signal field.
  • the third WUR signal field is transmitted on a third subchannel, and may include a third sync field and a third data field.
  • the fourth WUR signal field is transmitted in a fourth subchannel and may include a fourth sync field and a fourth data field.
  • the padding bit may be inserted after the third WUR signal field based on the L-LENGTH value.
  • the padding bit may be inserted after the fourth WUR signal field based on the L-LENGTH value.
  • the padding bits are also inserted in the third and fourth subchannels in order to equalize the length of the WUR packet transmitted through each subchannel (here, to equalize the length of the first WUR signal field). Can be.
  • Each of the first to fourth subchannels may be a 20 MHz subchannel.
  • the receiving device may include first to fourth receiving devices.
  • the first receiving device may decode the first WUR signal field transmitted in the first subchannel.
  • the second receiver may decode the second WUR signal field transmitted on the second subchannel.
  • the third receiver may decode the third WUR signal field transmitted in the third subchannel.
  • the fourth receiver may decode the fourth WUR signal field transmitted on the fourth subchannel.
  • the on symbol may be generated by inserting a sequence into 13 consecutive subcarriers in the first, second, third or fourth subchannels and performing an inverse fast fourier transform (IFFT).
  • the sequence may be set to a 13 length sequence, a 7 length sequence, or the like based on the data rate.
  • the IFFT may be a 64 point IFFT.
  • the first to fourth WUR signal fields may include a MAC header, a frame body field, and a frame check sequence (FCS) field.
  • the length of the MAC header may be 4 bytes.
  • the length of the frame body field may be 0, 8 or 16 bytes.
  • the length of the FCS field may be 2 bytes.
  • 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 by using an envelope detector, thereby reducing power consumed in decoding.
  • 24 is a flowchart illustrating a procedure of receiving a WUR packet by applying the OOK method according to the present embodiment.
  • FIG. 24 An example of FIG. 24 is performed at a receiving device, the receiving device may correspond to a low power wake-up receiver, and the transmitting device 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.
  • 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 length of the WUR packet may be different for each subchannel.
  • a third-party STA non-WUR STA irrelevant to the WUR transmission determines that the WUR packet transmission is terminated early or idle for a specific subchannel without the WUR packet, and performs channel access to perform WUR FDMA transmission. Can cause interference.
  • a padding bit is added to prevent interference by adjusting the lengths of WUR packets to which WUR FDMA transmitted on each subchannel is equal to each other. Accordingly, the TXTIME and L-LENGTH values are changed accordingly. Suggest.
  • 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 on-symbol may correspond to a symbol on which an on signal having an actual power value is transmitted.
  • the off-symbol may correspond to a symbol in which an off signal having no actual power value is transmitted.
  • step S2410 the receiving device receives a WUR packet generated by applying the On-Off Keying (OOK) method from the transmitting device.
  • OOK On-Off Keying
  • step S2420 the receiver decodes the WUR packet for the band supported by the receiver.
  • the WUR packet includes a legacy-signal (L-SIG) field, a first WUR signal field, and a second WUR signal field.
  • the WUR packet can be largely divided into a WUR signal part to which legacy preamble and FDMA are applied.
  • the legacy preamble may be duplicated in units of 20 MHz subchannels.
  • the legacy preamble may include a Legacy-Short Training Field (L-STF), a Legacy-Long Training Field (L-LTF), the L-SIG field, Binary Phase Shift Keying (BPSK) Mark1, and BPSK Mark2.
  • the WUR signal part may include the first and second WUR signal fields.
  • the first WUR signal field is transmitted on a first subchannel, and includes a first sync field and a first data field.
  • the second WUR signal field is transmitted on a second subchannel and includes a second sink field and a second data field.
  • the L-SIG field includes an L-LENGTH (Legacy-LENGTH) value that is a length of the longest WUR signal field among the first and second WUR signal fields. As described later, if the first WUR signal field is the longest among the WUR signal fields transmitted in each subchannel, the L-LENGTH value may be the length of the first WUR signal field.
  • L-LENGTH Legacy-LENGTH
  • a padding bit is inserted after the second WUR signal field based on the L-LENGTH value.
  • the padding bits may be inserted in order to equalize the length of the WUR packet transmitted through each subchannel (here, to equalize the length of the first WUR signal field).
  • a TXTIME value which is a transmission time of the WUR packet.
  • the TXTIME value is changed by reducing the number of OOK symbols included in the first data field by one.
  • the transmitter Since the last symbol of the first WUR signal field is an off symbol, the transmitter does not need to adjust the length from the other subchannel to the last off symbol. Since the LDR is applied to the first WUR signal field, the last symbol (off symbol) has a length of 4 us. That is, the transmitter can change the TXTIME value by subtracting the length of 4us. Reducing the number of OOK symbols by one means that the length of the last 4us off symbol is excluded.
  • the L-LENGTH value may be changed based on the changed TXTIME value.
  • the changed L-LENGTH value may include information about a length excluding the last symbol in the first WUR signal field.
  • the existing TXTIME value may be obtained through the following equation.
  • the changed TXTIME value may be obtained by replacing T Sym, iBW * N Sym, iBW , which is the last part of the equation, with T Sym, iBW * (N Sym, iBW- 1).
  • the existing L-LENGTH value may be obtained through the following equation.
  • the non-WUR STA may decode the changed L-LENGTH value and determine the length of the WUR packet up to the portion excluding the last off symbol 4us. Accordingly, the third party receiver may give an opportunity to transmit data by performing channel access more quickly (as soon as the last off symbol).
  • the first and second data fields may consist of an on symbol or an off symbol.
  • the on symbol may be generated by an On-Waveform Generator (On-WG) when the Manchester encoded bit is one.
  • the off symbol may be generated by Off-WG when the Manchester encoded bit is zero.
  • the Manchester encoded bit may be generated by having a source bit encoded by a Manchester based encoder. That is, the above-described embodiment is a first embodiment in which padding bits are inserted in a source bit stage before input to a Manchester-based encoder and a second embodiment in which padding bits are inserted in an encoded bit stage after being output by a Manchester-based encoder. Can be divided into The following description refers only to the first embodiment.
  • the Manchester encoded bit When LDR is applied to the first and second data fields, if the source bit is 0, the Manchester encoded bit may be 1010. If the source bit is 1, the Manchester encoded bit may be 0101. One Manchester encoded bit may have a length of 4 us.
  • the padding bit when the padding bit has a length of 32us, the padding bit is a Manchester encoded bit generated by the Manchester based encoder by adding an input padding bit to the source bit. If the input padding bit is 11, the padding bit may be 01010101. If the input padding bit is 01, the padding bit may be 10100101. Since the length of one Manchester encoded bit is 4us, the padding bit may have a length of 32us (4us * 8).
  • High data rate if the source bit is 0, the Manchester encoded bit is 10; if the source bit is 1, the Manchester encoded bit is 01 Can be.
  • One Manchester encoded bit may have a length of 2us.
  • the padding bit when the padding bit has a length of 32us, the padding bit is a Manchester encoded bit generated by the Manchester based encoder by adding an input padding bit to the source bit. If the input padding bit is 11111111, the padding bit may be 01010101010101. Since the length of one Manchester encoded bit is 2us, the padding bit may have a length of 32us (2us * 16).
  • the WUR packet may further include a third WUR signal field and a fourth WUR signal field.
  • the third WUR signal field is transmitted on a third subchannel, and may include a third sync field and a third data field.
  • the fourth WUR signal field is transmitted in a fourth subchannel and may include a fourth sync field and a fourth data field.
  • the padding bit may be inserted after the third WUR signal field based on the L-LENGTH value.
  • the padding bit may be inserted after the fourth WUR signal field based on the L-LENGTH value.
  • the padding bits are also inserted in the third and fourth subchannels in order to equalize the length of the WUR packet transmitted through each subchannel (here, to equalize the length of the first WUR signal field). Can be.
  • Each of the first to fourth subchannels may be a 20 MHz subchannel.
  • the receiving device may include first to fourth receiving devices.
  • the first receiving device may decode the first WUR signal field transmitted in the first subchannel.
  • the second receiver may decode the second WUR signal field transmitted on the second subchannel.
  • the third receiver may decode the third WUR signal field transmitted in the third subchannel.
  • the fourth receiver may decode the fourth WUR signal field transmitted on the fourth subchannel.
  • the on symbol may be generated by inserting a sequence into 13 consecutive subcarriers in the first, second, third or fourth subchannels and performing an inverse fast fourier transform (IFFT).
  • the sequence may be set to a 13 length sequence, a 7 length sequence, or the like based on the data rate.
  • the IFFT may be a 64 point IFFT.
  • the first to fourth WUR signal fields may include a MAC header, a frame body field, and a frame check sequence (FCS) field.
  • the length of the MAC header may be 4 bytes.
  • the length of the frame body field may be 0, 8 or 16 bytes.
  • the length of the FCS field may be 2 bytes.
  • 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 by using an envelope detector, thereby reducing power consumed in decoding.
  • 25 is a view for explaining an apparatus for implementing the method as described above.
  • the wireless device 100 of FIG. 25 is a transmission device capable of implementing the above-described embodiment and may operate as an AP STA.
  • the wireless device 150 of FIG. 25 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 transceivers 130 and 180 may transmit / receive radio signals and may be executed in a physical layer such as IEEE 802.11 / 3GPP.
  • the processors 110 and 160 are executed at 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 an application-specific integrated circuit (ASIC), another chipset, a logic circuit, and / or a data processor.
  • 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 transmitting device is as follows.
  • the processor 110 of the transmitting apparatus generates a WUR packet by applying an On-Off Keying (OOK) scheme and transmits the WUR packet to the receiving apparatus.
  • OOK On-Off Keying
  • the receiving device may be one of a plurality of low power wake up receivers.
  • the processor 160 of the receiving apparatus receives a WUR packet generated by applying an On-Off Keying (OOK) method from the transmitting apparatus, and decodes the WUR packet for a band supported by the receiving apparatus.
  • OOK On-Off Keying
  • Figure 26 shows 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, 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 transmitting apparatus, the processor 610 generates a WUR packet by applying an On-Off Keying (OOK) scheme, and transmits the WUR packet to the receiving apparatus.
  • OOK On-Off Keying
  • the processor 610 receives a WUR packet generated by applying an On-Off Keying (OOK) method from a transmitting apparatus, and decodes the WUR packet for a band supported by the receiving apparatus.
  • OOK On-Off Keying
  • the WUR packet includes a legacy-signal (L-SIG) field, a first WUR signal field, and a second WUR signal field.
  • the WUR packet can be largely divided into a WUR signal part to which legacy preamble and FDMA are applied.
  • the legacy preamble may be duplicated in units of 20 MHz subchannels.
  • the legacy preamble may include a Legacy-Short Training Field (L-STF), a Legacy-Long Training Field (L-LTF), the L-SIG field, Binary Phase Shift Keying (BPSK) Mark1, and BPSK Mark2.
  • the WUR signal part may include the first and second WUR signal fields.
  • the first WUR signal field is transmitted on a first subchannel, and includes a first sync field and a first data field.
  • the second WUR signal field is transmitted on a second subchannel and includes a second sink field and a second data field.
  • the L-SIG field includes an L-LENGTH (Legacy-LENGTH) value that is a length of the longest WUR signal field among the first and second WUR signal fields. As described later, if the first WUR signal field is the longest among the WUR signal fields transmitted in each subchannel, the L-LENGTH value may be the length of the first WUR signal field.
  • L-LENGTH Legacy-LENGTH
  • a padding bit is inserted after the second WUR signal field based on the L-LENGTH value.
  • the padding bits may be inserted in order to equalize the length of the WUR packet transmitted through each subchannel (here, to equalize the length of the first WUR signal field).
  • a TXTIME value which is a transmission time of the WUR packet.
  • the TXTIME value is changed by reducing the number of OOK symbols included in the first data field by one.
  • the transmitter Since the last symbol of the first WUR signal field is an off symbol, the transmitter does not need to adjust the length from the other subchannel to the last off symbol. Since the LDR is applied to the first WUR signal field, the last symbol (off symbol) has a length of 4 us. That is, the transmitter can change the TXTIME value by subtracting the length of 4us. Reducing the number of OOK symbols by one means that the length of the last 4us off symbol is excluded.
  • the L-LENGTH value may be changed based on the changed TXTIME value.
  • the changed L-LENGTH value may include information about a length excluding the last symbol in the first WUR signal field.
  • the existing TXTIME value may be obtained through the following equation.
  • the changed TXTIME value may be obtained by replacing T Sym, iBW * N Sym, iBW , which is the last part of the equation, with T Sym, iBW * (N Sym, iBW- 1).
  • the existing L-LENGTH value may be obtained through the following equation.
  • the non-WUR STA may decode the changed L-LENGTH value and determine the length of the WUR packet up to the portion excluding the last off symbol 4us. Accordingly, the third party receiver may give an opportunity to transmit data by performing channel access more quickly (as soon as the last off symbol).
  • the first and second data fields may consist of an on symbol or an off symbol.
  • the on symbol may be generated by an On-Waveform Generator (On-WG) when the Manchester encoded bit is one.
  • the off symbol may be generated by Off-WG when the Manchester encoded bit is zero.
  • the Manchester encoded bit may be generated by having a source bit encoded by a Manchester based encoder. That is, the above-described embodiment is a first embodiment in which padding bits are inserted in a source bit stage before input to a Manchester-based encoder and a second embodiment in which padding bits are inserted in an encoded bit stage after being output by a Manchester-based encoder. Can be divided into The following description refers only to the first embodiment.
  • the Manchester encoded bit When LDR is applied to the first and second data fields, if the source bit is 0, the Manchester encoded bit may be 1010. If the source bit is 1, the Manchester encoded bit may be 0101. One Manchester encoded bit may have a length of 4 us.
  • the padding bit when the padding bit has a length of 32us, the padding bit is a Manchester encoded bit generated by the Manchester based encoder by adding an input padding bit to the source bit. If the input padding bit is 11, the padding bit may be 01010101. If the input padding bit is 01, the padding bit may be 10100101. Since the length of one Manchester encoded bit is 4us, the padding bit may have a length of 32us (4us * 8).
  • High data rate if the source bit is 0, the Manchester encoded bit is 10; if the source bit is 1, the Manchester encoded bit is 01 Can be.
  • One Manchester encoded bit may have a length of 2us.
  • the padding bit when the padding bit has a length of 32us, the padding bit is a Manchester encoded bit generated by the Manchester based encoder by adding an input padding bit to the source bit. If the input padding bit is 11111111, the padding bit may be 01010101010101. Since the length of one Manchester encoded bit is 2us, the padding bit may have a length of 32us (2us * 16).
  • the WUR packet may further include a third WUR signal field and a fourth WUR signal field.
  • the third WUR signal field is transmitted on a third subchannel, and may include a third sync field and a third data field.
  • the fourth WUR signal field is transmitted in a fourth subchannel and may include a fourth sync field and a fourth data field.
  • the padding bit may be inserted after the third WUR signal field based on the L-LENGTH value.
  • the padding bit may be inserted after the fourth WUR signal field based on the L-LENGTH value.
  • the padding bits are also inserted in the third and fourth subchannels in order to equalize the length of the WUR packet transmitted through each subchannel (here, to equalize the length of the first WUR signal field). Can be.
  • Each of the first to fourth subchannels may be a 20 MHz subchannel.
  • the receiving device may include first to fourth receiving devices.
  • the first receiving device may decode the first WUR signal field transmitted in the first subchannel.
  • the second receiver may decode the second WUR signal field transmitted on the second subchannel.
  • the third receiver may decode the third WUR signal field transmitted in the third subchannel.
  • the fourth receiver may decode the fourth WUR signal field transmitted on the fourth subchannel.
  • the on symbol may be generated by inserting a sequence into 13 consecutive subcarriers in the first, second, third or fourth subchannels and performing an inverse fast fourier transform (IFFT).
  • the sequence may be set to a 13 length sequence, a 7 length sequence, or the like based on the data rate.
  • the IFFT may be a 64 point IFFT.
  • the first to fourth WUR signal fields may include a MAC header, a frame body field, and a frame check sequence (FCS) field.
  • the length of the MAC header may be 4 bytes.
  • the length of the frame body field may be 0, 8 or 16 bytes.
  • the length of the FCS field may be 2 bytes.
  • 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 by using an envelope detector, thereby reducing power consumed in decoding.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

La présente invention concerne un procédé et un appareil de transmission d'un paquet WUR à un système LAN sans fil. En particulier, un dispositif de transmission génère un paquet WUR en appliquant un procédé OOK, et transmet le paquet WUR à un dispositif de réception. Le paquet WUR comprend un champ L-SIG, un premier champ de signal WUR, et un second champ de signal WUR. Le premier champ de signal WUR est transmis sur un premier sous-canal et comprend un premier champ de synchronisation et un premier champ de données. Le second champ de signal WUR est transmis sur un second sous-canal et comprend un second champ de synchronisation et un second champ de données. Le champ L-SIG comprend une valeur L-LONGUEUR qui est une longueur du champ de signal WUR le plus long parmi les premier et second champs de signal WUR. Lorsqu'une LDR est appliquée au premier champ de signal WUR et que le dernier symbole du premier champ de signal WUR est un symbole d'arrêt, une valeur TXTEMPS, qui est un temps de transmission du paquet WUR, est modifiée.
PCT/KR2019/008961 2018-07-19 2019-07-19 Procédé et appareil de transmission de paquet de réveil dans un système lan sans fil WO2020017929A1 (fr)

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