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WO2018105950A1 - Procédé et dispositif de transmission de paquet de réveil dans un système lan sans fil - Google Patents

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

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Publication number
WO2018105950A1
WO2018105950A1 PCT/KR2017/013913 KR2017013913W WO2018105950A1 WO 2018105950 A1 WO2018105950 A1 WO 2018105950A1 KR 2017013913 W KR2017013913 W KR 2017013913W WO 2018105950 A1 WO2018105950 A1 WO 2018105950A1
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WIPO (PCT)
Prior art keywords
subband
zeros
sequence
wakeup packet
subcarriers
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PCT/KR2017/013913
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English (en)
Korean (ko)
Inventor
박은성
임동국
조한규
천진영
최진수
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엘지전자 주식회사
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Publication of WO2018105950A1 publication Critical patent/WO2018105950A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/02—Amplitude-modulated carrier systems, e.g. using on-off keying; Single sideband or vestigial sideband modulation
    • H04L27/04—Modulator circuits; Transmitter circuits
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/32—Carrier systems characterised by combinations of two or more of the types covered by groups H04L27/02, H04L27/10, H04L27/18 or H04L27/26
    • H04L27/34—Amplitude- and phase-modulated carrier systems, e.g. quadrature-amplitude modulated carrier systems
    • H04L27/38—Demodulator circuits; Receiver circuits
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W52/00—Power management, e.g. Transmission Power Control [TPC] or power classes
    • H04W52/02—Power saving arrangements
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
    • Y02D30/00—Reducing energy consumption in communication networks
    • Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks

Definitions

  • the present disclosure relates to a technique for performing low power communication in a WLAN system, and more particularly, to a method and apparatus for configuring and transmitting a wakeup packet for multiple users in a WLAN system.
  • next-generation WLANs 1) enhancements to the Institute of Electronics and Electronics Engineers (IEEE) 802.11 physical physical access (PHY) and medium access control (MAC) layers in the 2.4 GHz and 5 GHz bands, and 2) spectral efficiency and area throughput. aims to improve performance in real indoor and outdoor environments, such as in environments where interference sources exist, dense heterogeneous network environments, and high user loads.
  • IEEE Institute of Electronics and Electronics Engineers
  • PHY physical physical access
  • MAC medium access control
  • next-generation WLAN The environment mainly considered in the next-generation WLAN is a dense environment having many access points (APs) and a station (STA), and improvements in spectral efficiency and area throughput are discussed in such a dense environment.
  • next generation WLAN there is an interest in improving practical performance not only in an indoor environment but also in an outdoor environment, which is not much considered in a conventional WLAN.
  • next-generation WLAN there is a great interest in scenarios such as wireless office, smart home, stadium, hotspot, building / apartment, and AP based on the scenario.
  • STA are discussing about improving system performance in a dense environment with many STAs.
  • next-generation WLAN In addition, in the next-generation WLAN, there will be more discussion about improving system performance in outdoor overlapping basic service set (OBSS) environment, improving outdoor environment performance, and cellular offloading, rather than improving single link performance in one basic service set (BSS). It is expected.
  • the directionality of these next-generation WLANs means that next-generation WLANs will increasingly have a technology range similar to that of mobile communications. Considering the recent situation in which mobile communication and WLAN technology are discussed together in the small cell and direct-to-direct (D2D) communication area, the technical and business convergence of next-generation WLAN and mobile communication is expected to become more active.
  • D2D direct-to-direct
  • the present specification proposes a method and apparatus for constructing and transmitting a wakeup packet for multiple users in a WLAN system.
  • An example of the present specification proposes a method and apparatus for transmitting a wake-up packet through at least one subband to a WLAN system.
  • This embodiment can be operated in a transmitter and the user can correspond to a low power wake-up receiver.
  • the transmitting apparatus may correspond to the AP, and the user may correspond to the STA.
  • the term “on signal” may correspond to a signal having an actual power value.
  • the off signal may correspond to a signal that does not have an actual power value.
  • the first information may correspond to information 1 and the second information may correspond to information 0.
  • Tones correspond to subcarriers, and hereinafter, tones and subcarriers are used interchangeably.
  • the transmitter configures a wakeup packet.
  • the transmitter transmits the wakeup packet.
  • the wakeup packet includes a sequence consisting of first information and second information by applying an on-off keying (OOK) scheme.
  • OOK on-off keying
  • the first information is composed of an on signal
  • the second information is composed of an off signal
  • the on signal is transmitted through a first symbol generated by applying a first sequence to 13 consecutive subcarriers in a 20 MHz band and performing a 64-point Inverse Fast Fourier Transform (IFFT).
  • IFFT Inverse Fast Fourier Transform
  • one bit may be transmitted through one symbol generated by performing an IFFT.
  • the first symbol may correspond to an ON-symbol.
  • the wakeup packet is transmitted on at least one subband in the 20MHz band.
  • the subbands are allocated by the number of multiple users. For example, to construct a wakeup packet for four users, four subbands must be allocated. To configure a wakeup packet for three users, three subbands must be allocated. To configure a wakeup packet for two users, two subbands must be allocated. In this case, the subband is composed of the 13 subcarriers.
  • the at least one subband is composed of a sequence in which phase rotation is applied to a predetermined M sequence.
  • the subcarrier index of the 20 MHz band may be arranged in one subcarrier interval from the lowest subcarrier having -32 to the highest subcarrier having +31. That is, the 20 MHz band may consist of a total of 64 subcarriers, and each user's wakeup packet may consist of 13 subcarriers.
  • the subband used by each user has a size of about 4.06 MHz band. Accordingly, the wakeup packet can be transmitted to up to four users within the 20 MHz band.
  • the 20 MHz band includes a first guard subcarrier, a subcarrier constituting the first subband, a first null subcarrier, a subcarrier constituting the second subband, and a second
  • the subcarrier may comprise a null subcarrier, a subcarrier constituting a third subband, and a second guard subcarrier. That is, the subcarrier indices may be allocated in order from the low subcarrier to the high subcarrier. The same applies to the case where the number of multiple users is different.
  • the first guard subcarrier includes seven subcarriers
  • the second guard subcarrier includes six subcarriers
  • the first null subcarrier includes six subcarriers
  • the second null subcarrier may include six subcarriers.
  • the carrier may include six subcarriers. Since there are three multi-users, each user-specific subband may include a first subband, a second subband, and a third subband (total three user-specific subbands). Similarly, each of the subcarriers constituting the first subband, the subcarriers constituting the second subband, and the subcarriers constituting the third subband may include thirteen subcarriers.
  • a method of arranging subcarriers for wake-up packets in a 20 MHz band when the at least one subband is three may be represented as [7 13 6 13 6 13 6].
  • a wakeup packet may be transmitted by mapping a user to each of the three subbands. All of the subbands may be used or only a portion of the subbands may be used depending on the number of users transmitting the wakeup packet.
  • the wakeup packet When the wakeup packet is transmitted to three users, the wakeup packet may be transmitted to each of the three users through the first subband, the second subband, and the third subband. Since three users receive the wakeup packet, all three subbands can be used.
  • the wakeup packet is transmitted to two users
  • the wakeup packet is transmitted to each of the two users through two subbands of the first subband, the second subband, and the third subband. Can be. Since there are two users receiving wake-up packets, some of the three subbands (only two) can be used.
  • the wakeup packet When the wakeup packet is transmitted to one user, the wakeup packet may be transmitted to the one user through one subband of the first subband, the second subband, and the third subband. have. Since only one user receives the wakeup packet, some (only one) of the three subbands can be used.
  • the wakeup packet when the wakeup packet is transmitted to the user group, the wakeup packet may be transmitted to the user group through the first subband, the second subband, or the third subband. In each subband, a wakeup packet for one user group may be transmitted instead of a wakeup packet for one user.
  • the wakeup packet When the wakeup packet is broadcast, the wakeup packet may be transmitted to all users through the first subband, the second subband, or the third subband. In each subband, a wakeup packet for all users may be transmitted, instead of a wakeup packet for one user.
  • the transmitter may transmit a wakeup packet index.
  • the wakeup packet index may indicate a subcarrier index for the first subband, the second subband, or the third subband to be used by each user.
  • phase rotation may be applied not only to a tone plan but also to a sequence constituting each subband according to the corresponding tone plan.
  • the first subband may be configured as a sequence in which a phase rotation value a1 is applied to the predetermined M sequence.
  • the second subband may be configured as a sequence in which a phase rotation value a2 is applied to the predetermined M sequence.
  • the third subband may be configured as a sequence in which a phase rotation value a3 is applied to the predetermined M sequence.
  • A1 may be 1, a2 may be -j, and a3 may be 1.
  • a1 may be -1, a2 may be j, and a3 may be -1.
  • a1 may be j, a2 may be 1, and a3 may be j.
  • a1 may be -j, a2 may be -1, and a3 may be -j.
  • the subband within the 20 MHz band can be partially allocated to the user. Therefore, even if a tone plan is set for each subband for multiple users, the wakeup packet can be transmitted only to a specific subband to a specific user.
  • both coefficients of the subcarrier constituting the second subband and the subcarrier constituting the third subband may be set to zero. . That is, the second subband and the third subband may not be assigned to any user. In this case, the phase rotation value a1 may be applied to the first subband as it is.
  • the coefficients of the subcarriers constituting the first subband and the subcarriers constituting the third subband are both set to zero.
  • the first subband and the third subband may not be assigned to any user.
  • the phase rotation value a2 may be applied to the second subband as it is.
  • the coefficients of the subcarriers constituting the first subband and the subcarriers constituting the second subband are all zero. Can be set. That is, the first subband and the second subband may not be assigned to any user. In this case, the phase rotation value a3 may be applied to the third subband as it is.
  • the coefficients of the subcarriers constituting the third subband may be all set to zero. That is, the third subband may not be assigned to any user.
  • the phase rotation value a1 may be applied to the first subband as it is, and the phase rotation value a2 may be applied to the second subband.
  • the coefficients of the subcarriers constituting the first subband may be all set to zero. That is, the first subband may not be assigned to any user.
  • the phase rotation value a2 may be applied to the second subband as it is, and the phase rotation value a3 may be applied to the third subband.
  • the coefficients of the subcarriers constituting the second subband may be all set to zero. That is, the second subband may not be assigned to any user.
  • the phase rotation value a1 may be applied to the first subband as it is, and the phase rotation value a3 may be applied to the third subband.
  • the 20 MHz band includes a first guard subcarrier, a subcarrier constituting the first subband, a first null subcarrier, a subcarrier constituting the second subband, and a second Guard subcarrier order.
  • the first guard subcarrier may include 13 subcarriers
  • the second guard subcarrier may include 12 subcarriers
  • the first null subcarrier may include 13 subcarriers. Since there are two multi-users, each user-specific subband may include a first subband and a second subband (total two user-specific subbands). Similarly, each of the subcarriers constituting the first subband and the subcarriers constituting the second subband may include thirteen subcarriers.
  • the manner in which the subcarriers for the wakeup packet are arranged in the 20 MHz band when the at least one subband is two may be represented as [13 13 13 13 12].
  • a wakeup packet may be transmitted by mapping a user to each of the two subbands. All of the subbands may be used or only a portion of the subbands may be used depending on the number of users transmitting the wakeup packet.
  • the wakeup packet When the wakeup packet is transmitted to two users, the wakeup packet may be transmitted to each of the two users on the first subband and the second subband. Since there are two users receiving the wakeup packet, both subbands can be used.
  • the wakeup packet When the wakeup packet is transmitted to one user, the wakeup packet may be transmitted to the one user through one subband of the first subband and the second subband. Since only one user receives the wakeup packet, some (only one) of the two subbands may be used.
  • the wakeup packet when the wakeup packet is transmitted to the user group, the wakeup packet may be transmitted to the user group through the first subband or the second subband. In each subband, a wakeup packet for one user group may be transmitted instead of a wakeup packet for one user.
  • the wakeup packet When the wakeup packet is broadcast, the wakeup packet may be transmitted to all users on the first subband or the second subband. In each subband, a wakeup packet for all users may be transmitted, instead of a wakeup packet for one user.
  • phase rotation may be applied not only to a tone plan but also to a sequence constituting each subband according to the corresponding tone plan.
  • the first subband may be configured as a sequence in which a phase rotation value a1 is applied to the predetermined M sequence.
  • the second subband may be configured as a sequence in which a phase rotation value a2 is applied to the predetermined M sequence.
  • A1 may be 1 and a2 may be 1.
  • a1 may be -1 and a2 may be -1.
  • a1 may be j and a2 may be j.
  • a1 may be -j and a2 may be -j.
  • the subband within the 20 MHz band can be partially allocated to the user. Therefore, even if a tone plan is set for each subband for multiple users, the wakeup packet can be transmitted only to a specific subband to a specific user.
  • the coefficients of the subcarriers constituting the second subband may be all set to zero. That is, the second subband may not be assigned to any user.
  • the phase rotation value a1 may be applied to the first subband as it is.
  • the coefficients of the subcarriers constituting the first subband may be all set to zero. That is, the first subband may not be assigned to any user.
  • the phase rotation value a2 may be applied to the second subband as it is.
  • the transmitter may transmit a wakeup packet index.
  • the wakeup packet index may indicate a subcarrier index for the first subband or the second subband to be used by each user.
  • the subcarrier index may be indicated in advance in the main radio terminal instead of the wakeup packet. This allows an accurate indication of which user the subcarrier for each wakeup packet is assigned to.
  • a wakeup packet is configured and transmitted, thereby reducing power consumption by using an envelope detector when decoding the wakeup packet. Therefore, the receiving device can decode the wakeup packet to the minimum power.
  • the transmitter configures a wakeup packet for up to four users in the 20MHz band, thereby minimizing the interference between adjacent bands while minimizing the interference between wakeup packets of multiple users.
  • 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.
  • 11 is a flowchart illustrating a procedure of configuring a wake-up packet for multiple users by applying phase rotation for each frequency band according to the present embodiment.
  • FIG. 12 is a block diagram illustrating a wireless device to which the present embodiment can be applied.
  • WLAN wireless local area network
  • BSS infrastructure basic service set
  • IEEE Institute of Electrical and Electronic Engineers
  • the WLAN system may include one or more infrastructure BSSs 100 and 105 (hereinafter, BSS).
  • BSSs 100 and 105 are a set of APs and STAs such as an access point 125 and a STA1 (station 100-1) capable of successfully synchronizing and communicating with each other, and do not indicate a specific area.
  • the BSS 105 may include one or more joinable STAs 105-1 and 105-2 to one AP 130.
  • the BSS may include at least one STA, APs 125 and 130 for providing a distribution service, and a distribution system (DS) 110 for connecting a plurality of APs.
  • STA STA
  • APs 125 and 130 for providing a distribution service
  • DS distribution system
  • the distributed system 110 may connect several BSSs 100 and 105 to implement an extended service set (ESS) 140 which is an extended service set.
  • ESS 140 may be used as a term indicating one network in which one or several APs 125 and 230 are connected through the distributed system 110.
  • APs included in one ESS 140 may have the same service set identification (SSID).
  • the portal 120 may serve as a bridge for connecting the WLAN network (IEEE 802.11) with another network (for example, 802.X).
  • a network between the APs 125 and 130 and a network between the APs 125 and 130 and the STAs 100-1, 105-1 and 105-2 may be implemented. However, it may be possible to perform communication by setting up a network even between STAs without the APs 125 and 130.
  • a network that performs communication by establishing a network even between STAs without APs 125 and 130 is defined as an ad-hoc network or an independent basic service set (BSS).
  • FIG. 1 is a conceptual diagram illustrating an IBSS.
  • the IBSS is a BSS operating in an ad-hoc mode. Since IBSS does not contain an AP, there is no centralized management entity. That is, in the IBSS, the STAs 150-1, 150-2, 150-3, 155-4, and 155-5 are managed in a distributed manner. In the IBSS, all STAs 150-1, 150-2, 150-3, 155-4, and 155-5 may be mobile STAs, and access to a distributed system is not allowed, thus making a self-contained network. network).
  • a STA is any functional medium that includes medium access control (MAC) conforming to the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard and a physical layer interface to a wireless medium. May be used to mean both an AP and a non-AP STA (Non-AP Station).
  • MAC medium access control
  • IEEE Institute of Electrical and Electronics Engineers
  • the STA may include a mobile terminal, a wireless device, a wireless transmit / receive unit (WTRU), a user equipment (UE), a mobile station (MS), a mobile subscriber unit ( It may also be called various names such as a mobile subscriber unit or simply a user.
  • WTRU wireless transmit / receive unit
  • UE user equipment
  • MS mobile station
  • UE mobile subscriber unit
  • It may also be called various names such as a mobile subscriber unit or simply a user.
  • the term "user” may be used in various meanings, for example, may also be used to mean an STA participating in uplink MU MIMO and / or uplink OFDMA transmission in wireless LAN communication. It is not limited to this.
  • FIG. 2 is a diagram illustrating an example of a PPDU used in the IEEE standard.
  • PPDUs PHY protocol data units
  • LTF and STF fields included training signals
  • SIG-A and SIG-B included control information for the receiving station
  • data fields included user data corresponding to the PSDU.
  • This embodiment proposes an improved technique for the signal (or control information field) used for the data field of the PPDU.
  • the signal proposed in this embodiment may be applied on a high efficiency PPDU (HE PPDU) according to the IEEE 802.11ax standard. That is, the signals to be improved in the present embodiment may be HE-SIG-A and / or HE-SIG-B included in the HE PPDU. Each of HE-SIG-A and HE-SIG-B may also be represented as SIG-A or SIG-B.
  • the improved signal proposed by this embodiment is not necessarily limited to the HE-SIG-A and / or HE-SIG-B standard, and controls / control of various names including control information in a wireless communication system for transmitting user data. Applicable to data fields.
  • FIG. 3 is a diagram illustrating an example of a HE PPDU.
  • the control information field proposed in this embodiment may be HE-SIG-B included in the HE PPDU as shown in FIG. 3.
  • the HE PPDU according to FIG. 3 is an example of a PPDU for multiple users.
  • the HE-SIG-B may be included only for the multi-user, and the HE-SIG-B may be omitted in the PPDU for the single user.
  • a HE-PPDU for a multiple user includes a legacy-short training field (L-STF), a legacy-long training field (L-LTF), a legacy-signal (L-SIG), High efficiency-signal A (HE-SIG-A), high efficiency-signal-B (HE-SIG-B), high efficiency-short training field (HE-STF), high efficiency-long training field (HE-LTF) It may include a data field (or MAC payload) and a PE (Packet Extension) field. Each field may be transmitted during the time period shown (ie, 4 or 8 ms, etc.).
  • the PPDU used in the IEEE standard is mainly described as a PPDU structure transmitted over a channel bandwidth of 20 MHz.
  • the PPDU structure transmitted on a bandwidth wider than the channel bandwidth of 20 MHz may be a structure in which linear scaling of the PPDU structure used in the channel bandwidth of 20 MHz is applied.
  • the PPDU structure used in the IEEE standard is generated based on 64 Fast Fourier Tranforms (FTFs), and a CP portion (cyclic prefix portion) may be 1/4.
  • FFTs Fast Fourier Tranforms
  • CP portion cyclic prefix portion
  • the length of the effective symbol interval (or FFT interval) may be 3.2us
  • the CP length is 0.8us
  • the symbol duration may be 4us (3.2us + 0.8us) plus the effective symbol interval and the CP length.
  • Wireless networks are ubiquitous, usually indoors and often installed outdoors. Wireless networks use various techniques to send and receive information. For example, but not limited to, two widely used technologies for communication are those that comply with IEEE 802.11 standards such as the IEEE 802.11n standard and the IEEE 802.11ac standard.
  • the IEEE 802.11 standard specifies a common Medium Access Control (MAC) layer that provides a variety of features to support the operation of IEEE 802.11-based wireless LANs (WLANs).
  • the MAC layer utilizes protocols that coordinate access to shared radios and improve communications over wireless media, such as IEEE 802.11 stations (such as a PC's wireless network card (NIC) or other wireless device or station (STA) and access point ( Manage and maintain communication between APs).
  • IEEE 802.11 stations such as a PC's wireless network card (NIC) or other wireless device or station (STA) and access point ( Manage and maintain communication between APs).
  • IEEE 802.11ax is the successor to 802.11ac and has been proposed to improve the efficiency of WLAN networks, especially in high density areas such as public hotspots and other high density traffic areas.
  • IEEE 802.11 can also use Orthogonal Frequency Division Multiple Access (OFDMA).
  • OFDMA Orthogonal Frequency Division Multiple Access
  • the High Efficiency WLAN Research Group (HEW SG) within the IEEE 802.11 Work Group is dedicated to improving system throughput / area in high-density scenarios of APs (access points) and / or STAs (stations) in relation to the IEEE 802.11 standard. We are considering improving efficiency.
  • Wearable devices and small computing devices such as sensors and mobile devices are constrained by small battery capacities, but use wireless communication technologies such as Wi-Fi, Bluetooth®, and Bluetooth® Low Energy (BLE). Support, connect to and exchange data with other computing devices such as smartphones, tablets, and computers. Since these communications consume power, it is important to minimize the energy consumption of such communications in these devices.
  • One ideal strategy to minimize energy consumption is to power off the communication block as frequently as possible while maintaining data transmission and reception without increasing delay too much. That is, the communication block is transmitted immediately before the data reception, and only when there is data to wake up, the communication block is turned on and the communication block is turned off for the remaining time.
  • LP-WUR low-power wake-up receiver
  • the communication system (or communication subsystem) described herein includes a main radio (802.11) and a low power wake up receiver.
  • the main radio is used for transmitting and receiving user data.
  • the main radio is turned off if there are no data or packets to transmit.
  • the low power wake-up receiver wakes up the main radio when there is a packet to receive. At this time, the user data is transmitted and received by the main radio.
  • the low power wake-up receiver is not for user data. It is simply a receiver to wake up the main radio. In other words, the transmitter is not included.
  • the low power wake-up receiver is active while the main radio is off.
  • Low power wake-up receivers target a target power consumption of less than 1 mW in an active state.
  • low power wake-up receivers use a narrow bandwidth of less than 5 MHz.
  • the target transmission range of the low power wake-up receiver is the same as that of the existing 802.11.
  • 4 illustrates a low power wake-up receiver in an environment in which data is not received.
  • 5 illustrates a low power wake-up receiver in an environment in which data is received.
  • one way to implement an ideal transmission and reception strategy is a main radio such as Wi-Fi, Bluetooth® radio, or Bluetooth® Radio (BLE). Adding a low power wake-up receiver (LP-WUR) that can wake up.
  • LP-WUR low power wake-up receiver
  • the Wi-Fi / BT / BLE 420 is turned off and the low power wake-up receiver 430 is turned on without receiving data.
  • LP-WUR low power wake-up receiver
  • the low power wakeup receiver 530 may receive the entire Wi-Fi / BT / BLE radio 520 so that the data packet following the wakeup packet can be correctly received. Wake up). In some cases, however, actual data or IEEE 802.11 MAC frames may be included in the wakeup packet. In this case, it is not necessary to wake up the entire Wi-Fi / BT / BLE radio 520, but only a part of the Wi-Fi / BT / BLE radio 520 to perform the necessary process. This can result in significant power savings.
  • One example technique disclosed herein defines a method for a granular wakeup mode for Wi-Fi / BT / BLE using a low power wakeup receiver. For example, the actual data contained in the wakeup packet can be passed directly to the device's memory block without waking up the Wi-Fi / BT / BLE radio.
  • a wakeup packet contains an IEEE 802.11 MAC frame
  • only the MAC processor of the Wi-Fi / BT / BLE wireless device needs to wake up to process the IEEE 802.11 MAC frame included in the wakeup. That is, the PHY module of the Wi-Fi / BT / BLE radio can be turned off or kept in a low power mode.
  • Wi-Fi / BT / BLE radios that use low power wake-up receivers, requiring that the Wi-Fi / BT / BLE radio be powered on when a wake-up packet is received.
  • only necessary parts (or components) of the Wi-Fi / BT / BLE radio can be selectively woken up, thereby saving energy and reducing the waiting time.
  • Many solutions that use low-power wake-up receivers to receive wake-up packets wake up the entire Wi-Fi / BT / BLE radio.
  • One exemplary aspect discussed herein wakes up only the necessary portions of the Wi-Fi / BT / BLE radio required to process the received data, saving significant amounts of energy and reducing unnecessary latency in waking up the main radio. Can be.
  • the low power wake-up receiver 530 may wake up the main radio 520 based on the wake-up packet transmitted from the transmitter 500.
  • the transmitter 500 may be set to transmit a wakeup packet to the receiver 510.
  • the low power wake-up receiver 530 may be instructed to wake up the main radio 520.
  • FIG. 6 shows an example of a wakeup packet structure according to the present embodiment.
  • the wakeup packet may include one or more legacy preambles.
  • One or more legacy devices may decode or process the legacy preamble.
  • the wakeup packet may include a payload after the legacy preamble.
  • the payload may be modulated by a simple modulation scheme, for example, an On-Off Keying (OOK) modulation scheme.
  • OOK On-Off Keying
  • the transmitter may be configured to generate and / or transmit a wakeup packet 600.
  • the receiving device may be configured to process the received wakeup packet 600.
  • the wakeup packet 600 may include a legacy preamble or any other preamble 610 as defined by the IEEE 802.11 specification.
  • the wakeup packet 600 may include a payload 620.
  • Legacy preambles provide coexistence with legacy STAs.
  • the legacy preamble 610 for coexistence uses the L-SIG field to protect the packet.
  • the 802.11 STA may detect the start of a packet through the L-STF field in the legacy preamble 610.
  • the 802.11 STA can know the end of the packet through the L-SIG field in the legacy preamble 610.
  • a BPSK modulated symbol after the L-SIG a false alarm of an 802.11n terminal can be reduced.
  • One symbol (4us) modulated with BPSK also has a 20MHz bandwidth like the legacy part.
  • the legacy preamble 610 is a field for third party legacy STAs (STAs not including LP-WUR).
  • the legacy preamble 610 is not decoded from the LP-WUR.
  • the payload 620 may include a wakeup preamble 622.
  • Wake-up preamble 622 may include a sequence of bits configured to identify wake-up packet 600.
  • the wakeup preamble 622 may include, for example, a PN sequence.
  • the payload 620 may include a MAC header 624 including address information of a receiver receiving the wakeup packet 600 or an identifier of the receiver.
  • the payload 620 may include a frame body 626 that may include other information of the wakeup packet.
  • the frame body 626 may include length or size information of the payload.
  • the payload 620 may include a Frame Check Sequence (FCS) field 628 that includes a Cyclic Redundancy Check (CRC) value.
  • FCS Frame Check Sequence
  • CRC Cyclic Redundancy Check
  • it may include a CRC-8 value or a CRC-16 value of the MAC header 624 and the frame body 626.
  • FIG. 7 shows a signal waveform of a wakeup packet according to the present embodiment.
  • the wakeup packet 700 includes a legacy preamble (802.11 preamble, 710) and a payload modulated by OOK. That is, the legacy preamble and the new LP-WUR signal waveform coexist.
  • the legacy preamble 710 may be modulated according to the OFDM modulation scheme. That is, the legacy preamble 710 is not applied to the OOK method.
  • the payload may be modulated according to the OOK method.
  • the wakeup preamble 722 in the payload may be modulated according to another modulation scheme.
  • the payload may be transmitted on a channel bandwidth of about 4.06 MHz. This will be described later in the OOK pulse design method.
  • FIG. 8 is a diagram for describing a principle in which power consumption is determined according to a ratio of 1 and 0 of bit values constituting binary sequence information using the OOK method.
  • OOK modulation can be performed. That is, in consideration of the bit values of the binary sequence information, it is possible to perform the communication of the OOK modulation method.
  • the light emitting diode is used for visible light communication
  • the light emitting diode is turned on when the bit value constituting the binary sequence information is 1, and the light emitting diode is turned off when the bit value is 0.
  • the light emitting diode can be made to blink.
  • the receiver receives and restores data transmitted in the form of visible light, thereby enabling communication using visible light.
  • the blinking of the light emitting diode cannot be perceived by the human eye, the person feels that the illumination is continuously maintained.
  • FIG. 8 information in the form of a binary sequence having 10 bit values is used.
  • FIG. 8 there is information in the form of a binary sequence having a value of '1001101011'.
  • the bit value is 1
  • the transmitter is turned on
  • the bit value is 0,
  • the transmitter is turned off
  • the symbol is turned on at 6 bit values out of 10 bit values.
  • the power consumption is 60% according to the duty cycle of FIG. 8.
  • the power consumption of the transmitter is determined according to the ratio of 1 and 0 constituting the binary sequence information.
  • the ratio of 1 and 0 which constitutes information in binary sequence form, must also be maintained.
  • the ratio of 1 and 0 constituting the information in the form of a binary sequence must also be maintained.
  • the receiver is mainly a wake-up receiver (WUR)
  • WUR wake-up receiver
  • the main reason for using OOK is that the power consumption is very low when decoding the received signal. Until the decoding is performed, there is no significant difference in power consumption in the main radio or WUR, but a large difference occurs in the decoding process. Below is the approximate power consumption.
  • the existing Wi-Fi power consumption is about 100mW.
  • power consumption of Resonator + Oscillator + PLL (1500uW)-> LPF (300uW)-> ADC (63uW)-> decoding processing (OFDM receiver) (100mW) may occur.
  • -WUR power consumption is about 1mW.
  • power consumption of Resonator + Oscillator (600uW)-> LPF (300uW)-> ADC (20uW)-> decoding processing (Envelope detector) (1uW) may occur.
  • the OFDM transmitter of 802.11 can be reused to generate OOK pulses.
  • the transmitter can generate a sequence having 64 bits by applying a 64-point IFFT as in 802.11.
  • the transmitter should generate the payload of the wakeup packet by modulating the OOK method.
  • the OOK method is applied to the ON-signal.
  • the on signal is a signal having an actual power value
  • the off signal corresponds to a signal having no actual power value.
  • the off signal is also applied to the OOK method, but the signal is not generated using the transmitter, and since no signal is actually transmitted, it is not considered in the configuration of the wakeup packet.
  • information (bit) 1 may be an on signal and information (bit) 0 may be an off signal.
  • information 1 may indicate a transition from an off signal to an on signal
  • information 0 may indicate a transition from an on signal to an off signal.
  • the information 1 may indicate the transition from the on signal to the off signal
  • the information 0 may indicate the transition from the off signal to the on signal. Manchester coding scheme will be described later.
  • the transmitter applies a sequence by selecting 13 consecutive subcarriers of a 20 MHz band as a reference band as a sample.
  • 13 subcarriers located among the subcarriers in the 20 MHz band are selected as samples. That is, a subcarrier whose subcarrier index is from -6 to +6 is selected from the 64 subcarriers.
  • the subcarrier index 0 may be nulled to 0 as the DC subcarrier.
  • subcarrier spacing is 312.5 KHz
  • 13 subcarriers have a channel bandwidth of about 4.06 MHz. That is, it can be said that power is provided only for 4.06MHz in the 20MHz band in the frequency domain.
  • SNR signal to noise ratio
  • the power consumption of the AC / DC converter of the receiver can be reduced.
  • the power consumption can be reduced by reducing the sampling frequency band to 4.06MHz.
  • the transmitter may generate one on-signal in the time domain by performing a 64-point IFFT on 13 subcarriers.
  • One on-signal has a size of 1 bit. That is, a sequence composed of 13 subcarriers may correspond to 1 bit.
  • the transmitter may not transmit the off signal at all.
  • IFFT a 3.2us symbol may be generated, and if a CP (Cyclic Prefix, 0.8us) is included, one symbol having a length of 4us may be generated. That is, one bit indicating one on-signal may be loaded in one symbol.
  • the reason for configuring and sending the bits as in the above-described embodiment is to reduce power consumption by using an envelope detector in the receiver. As a result, the receiving device can decode the packet with the minimum power.
  • the basic data rate for one information may be 125 Kbps (8us) or 62.5Kbps (16us).
  • each signal having a length of K in the 20 MHz band may be transmitted on K consecutive subcarriers of a total of 64 subcarriers. That is, K may correspond to the bandwidth of the OOK pulse by the number of subcarriers used to transmit a signal. All other coefficients of the K subcarriers are zero.
  • the indexes of the K subcarriers used by the signal corresponding to the information 0 and the information 1 are the same.
  • the subcarrier index used may be represented as 33-floor (K / 2): 33 + ceil (K / 2) -1.
  • the information 1 and the information 0 may have the following values.
  • the alpha is a power normalization factor and may be, for example, 1 / sqrt (K).
  • FIG. 10 is an explanatory diagram of a Manchester coding scheme according to the present embodiment.
  • Manchester coding is a type of line coding, and may indicate information as shown in the following table in a manner in which a transition of a magnitude value occurs in the middle of one bit period.
  • Manchester coding means a method of converting data from 1 to 01, 0 to 10, 1 to 10, and 0 to 01.
  • Table 1 shows an example in which data is converted from 1 to 10 and 0 to 01 using Manchester coding.
  • bit string to be transmitted As shown in Fig. 10, the bit string to be transmitted, the Manchester coded signal, the clock reproduced on the receiving side, and the data reproduced on the clock are shown in order from top to bottom.
  • the transmitting side transmits data using the Manchester coding scheme
  • the receiving side reads the data a little later on the basis of the transition point transitioning from 1 ⁇ 0 or 0 ⁇ 1 and recovers the data, and then transitions to 1 ⁇ 0 or 0 ⁇ 1.
  • the clock is recovered by recognizing the transition point as the clock transition point.
  • the symbol is divided based on the transition point, it can be simply decoded by comparing the power at the front and the back at the center of the symbol.
  • the bit string to be transmitted is 10011101
  • the Manchester coded signal is 0110100101011001
  • the clock reproduced on the receiving side recognizes the transition point of the Manchester coded signal as the transition point of the clock. Then, the data is recovered by using the reproduced clock.
  • this method can use the TXD pin for data transmission and the RXD pin for reception by using only the data transmission channel. Therefore, synchronized bidirectional transmission is possible.
  • the present specification proposes a scheme in which 13 subcarriers are configured in a 20 MHz band when a WUR packet is sent to each user using 13 subcarriers in a situation where there are multiple users.
  • the existing 20 MHz has a total of 64 subcarriers, and each user's wakeup packet is composed of 13 subcarriers.
  • the wakeup packet can be sent to up to four users within 20 MHz.
  • 20 MHz used may be a primary 20 MHz.
  • the existing guard tone may or may not be considered.
  • the guard tone is a subcarrier that is not used for interference prevention, and is also called an unused subcarrier or a guard subcarrier.
  • a set of one or more consecutive guard tones is called a guard region
  • the present specification proposes a sequence and phase rotation scheme to be mapped to each subband in consideration of a method in which each subband including 13 subcarriers in a 20 MHz band can be configured.
  • a wakeup packet of each user may be configured based on a sequence of length 13 as follows.
  • the following M1 sequence is the best sequence in terms of peak-to-average power ratio (PAPR) when only one user is used.
  • the M2 sequence is a Barker sequence used when designing an 802.11ax STF.
  • M1 ⁇ 1,1,1, -1, -1, -1,1,1, -1,1,1, -1,1 ⁇
  • M2 ⁇ 1,1,1,1,1, -1, -1,1,1, -1,1, -1,1 ⁇
  • the M3 sequence is an optimized sequence in terms of PAPR
  • M4 is a sequence in which the average power of the CP and the data part is most similar.
  • M3 ⁇ 1,1,1, -1, -1, -1,0, -1,1, -1, -1,1, -1 ⁇
  • M4 ⁇ -1, -1, -1,1,1, -1,0, -1, -1, -1,1, -1,1 ⁇
  • the sequence can be used when each user sends an on signal (or on symbol).
  • a WUR packet for multiple users is composed of 2 to 4 subbands and can be transmitted to 2 to 4 users.
  • the WUR packet for the multi-user can optimize the phase rotation value for each user in terms of PAPR when a signal (or on-symbol) in which each user's subband is formed of the M1 to M4 sequences is generated.
  • the phase rotation value may be determined as one of 1, -1, j, and -j.
  • PAPR may be optimized by considering a situation in which all subbands are composed of on signals (or on symbols). Although some subbands can be optimized by considering off-signals (or off-symbols), the phase rotation value can be determined only by considering all on-signals (or on-symbols) to reduce complexity. However, the phase rotation value at this time may be applied as it is even when some of the off signal (or off symbol).
  • a four-fold IFFT may be considered when calculating the PAPR.
  • phase rotation values may simply be fixed to all ones (or to the same one value).
  • the following shows various examples of configuring subbands within the 20 MHz band according to the number of multiple users. Specifically, an example of a sequence to be mapped to each subband and a phase rotation value applied to each sequence is shown.
  • two 13 tones (13 subcarriers) can be configured for WUR packets.
  • Each number above represents the number of subcarriers from -32 to 31 of the 20 MHz subcarrier indexes, the underlined number indicates the guard tone, and the italic type indicates the tone (or subcarrier) on which the WUR packet is carried. ), And the rest means null tones.
  • Null tones can be used as guard tones between WUR packets. Each configuration is designed so that the negative part and the positive part are configured as symmetry as possible as evenly as possible. The same applies to all other cases.
  • each of 32 subcarriers is allocated, and 13 WUR packet subcarriers (signal bandwidths) and 19 guard subcarriers can be configured. It can be configured in the form of [10 13 9].
  • the guard subcarrier between subbands consisting of 13 subcarriers and the guard subcarrier between subbands consisting of 13 subcarriers and the main radio (when edge tone is 4 or 3) 15 can always be the same.
  • tone plan such as case 3.
  • using the M2 sequence in this case and the proposed phase rotation value in this case may be a gain from the PAPR perspective.
  • Another example is when a wakeup packet is sent to three users (there are three subbands).
  • the guard subcarriers between 13 subcarriers and between 13 subcarriers and the main radio can be equal to 9 have.
  • each 22 or 21 subcarriers are allocated and consist of 13 WUR packets of subcarriers (signal bandwidth) and 9 or 8 guard subcarriers. It may be in the form of [5 13 4] or [4 13 4].
  • Guard subcarriers consisting of 13 subcarriers for adjacent 20 MHz WUR transmissions. Eight or nine subcarriers. For adjacent 20 MHz for main radio transmission, between subbands consisting of 13 subcarriers and 13 subcarriers. The guard subcarriers between the subband and the main radio (when edge tones are 4 or 3) can be equalized to eight.
  • Case 3 or 11 may be advantageous when considering guard subcarriers and adjacent 20 MHz.
  • a wakeup packet is sent to four users (there are four subbands).
  • each of 16 subcarriers may be allocated, and may consist of 13 carrier subcarriers (signal bandwidths) and 3 guard subcarriers [2 13 1] It can be configured in the form of.
  • tone plan such as case 3.
  • the use of the M2 sequence in this case and the proposed phase rotation value in this case can be a benefit from the PAPR perspective.
  • case 8 may be advantageous.
  • case 1 or case 4 use the M2 sequence and in this case configure the subbands using the proposed phase rotation values.
  • Another example is when a wakeup packet is sent to three users (there are three subbands).
  • tone plan such as case 5 and in this case the proposed phase rotation value.
  • tone plan such as case 6 and in this case the proposed phase rotation value.
  • Case 3 or 11 may be advantageous when considering guard subcarriers and adjacent 20 MHz.
  • a wakeup packet is sent to four users (there are four subbands).
  • Another example is when a wakeup packet is sent to three users (there are three subbands).
  • tone plan such as case 4 and in this case the proposed phase rotation value.
  • tone plan such as case 6 and in this case the proposed phase rotation value.
  • Case 3 or 11 may be advantageous when considering guard subcarriers and adjacent 20 MHz.
  • a wakeup packet is sent to four users (there are four subbands).
  • tone plan such as case 5 and in this case the proposed phase rotation value.
  • tone plan such as case 6 and in this case the proposed phase rotation value.
  • phase rotation value optimized for each case may be used as it is.
  • the optimized phase rotation value described above may be applied as follows.
  • the second subband indicated by parentheses is not assigned to any user, and all subcarriers of the subband may be set to a coefficient of zero.
  • a single user may use some subbands in the 20 MHz band.
  • the sequence constituting the subband may be an M3 or M4 sequence including DC (null in the middle of the sequence).
  • M1 or M2
  • M3 or M4
  • case 1 the first subband, the third subband uses the M1 (or M2) sequence, and the second is located at DC, and the M3 (or M4) sequence is located. Can be used. Case 1, where three users use different sequences, looks like this:
  • (a1, a2, a3) (1, j, 1) or (-1, -j, -1) or (j, -1, j) or (-j, 1, -j)
  • each subband in the 20 MHz band can be configured using one same sequence.
  • 11 is a flowchart illustrating a procedure of configuring a wake-up packet for multiple users by applying phase rotation for each frequency band according to the present embodiment.
  • FIG. 11 An example of FIG. 11 is performed in a transmitter, and a user may correspond to a low power wake-up receiver.
  • the transmitting apparatus may correspond to the AP, and the user may correspond to the STA.
  • the term “on signal” may correspond to a signal having an actual power value.
  • the off signal may correspond to a signal that does not have an actual power value.
  • the first information may correspond to information 1 and the second information may correspond to information 0.
  • Tones correspond to subcarriers, and hereinafter, tones and subcarriers are used interchangeably.
  • step S1110 the transmitter configures a wakeup packet.
  • the transmitter transmits the wakeup packet.
  • the wakeup packet includes a sequence consisting of first information and second information by applying an on-off keying (OOK) scheme.
  • OOK on-off keying
  • the first information is composed of an on signal
  • the second information is composed of an off signal
  • the on signal is transmitted through a first symbol generated by applying a first sequence to 13 consecutive subcarriers in a 20 MHz band and performing a 64-point Inverse Fast Fourier Transform (IFFT).
  • IFFT Inverse Fast Fourier Transform
  • one bit may be transmitted through one symbol generated by performing an IFFT.
  • the first symbol may correspond to an ON-symbol.
  • the wakeup packet is transmitted on at least one subband in the 20MHz band.
  • the subbands are allocated by the number of multiple users. For example, to construct a wakeup packet for four users, four subbands must be allocated. To configure a wakeup packet for three users, three subbands must be allocated. To configure a wakeup packet for two users, two subbands must be allocated. In this case, the subband is composed of the 13 subcarriers.
  • the at least one subband is composed of a sequence in which phase rotation is applied to a predetermined M sequence.
  • the subcarrier index of the 20 MHz band may be arranged in one subcarrier interval from the lowest subcarrier having -32 to the highest subcarrier having +31. That is, the 20 MHz band may consist of a total of 64 subcarriers, and each user's wakeup packet may consist of 13 subcarriers.
  • the subband used by each user has a size of about 4.06 MHz band. Accordingly, the wakeup packet can be transmitted to up to four users within the 20 MHz band.
  • the 20 MHz band includes a first guard subcarrier, a subcarrier constituting the first subband, a first null subcarrier, a subcarrier constituting the second subband, and a second
  • the subcarrier may comprise a null subcarrier, a subcarrier constituting a third subband, and a second guard subcarrier. That is, the subcarrier indices may be allocated in order from the low subcarrier to the high subcarrier. The same applies to the case where the number of multiple users is different.
  • the first guard subcarrier includes seven subcarriers
  • the second guard subcarrier includes six subcarriers
  • the first null subcarrier includes six subcarriers
  • the second null subcarrier may include six subcarriers.
  • the carrier may include six subcarriers. Since there are three multi-users, each user-specific subband may include a first subband, a second subband, and a third subband (total three user-specific subbands). Similarly, each of the subcarriers constituting the first subband, the subcarriers constituting the second subband, and the subcarriers constituting the third subband may include thirteen subcarriers.
  • a method of arranging subcarriers for wake-up packets in a 20 MHz band when the at least one subband is three may be represented as [7 13 6 13 6 13 6].
  • a wakeup packet may be transmitted by mapping a user to each of the three subbands. All of the subbands may be used or only a portion of the subbands may be used depending on the number of users transmitting the wakeup packet.
  • the wakeup packet When the wakeup packet is transmitted to three users, the wakeup packet may be transmitted to each of the three users through the first subband, the second subband, and the third subband. Since three users receive the wakeup packet, all three subbands can be used.
  • the wakeup packet is transmitted to two users
  • the wakeup packet is transmitted to each of the two users through two subbands of the first subband, the second subband, and the third subband. Can be. Since there are two users receiving wake-up packets, some of the three subbands (only two) can be used.
  • the wakeup packet When the wakeup packet is transmitted to one user, the wakeup packet may be transmitted to the one user through one subband of the first subband, the second subband, and the third subband. have. Since only one user receives the wakeup packet, some (only one) of the three subbands can be used.
  • the wakeup packet when the wakeup packet is transmitted to the user group, the wakeup packet may be transmitted to the user group through the first subband, the second subband, or the third subband. In each subband, a wakeup packet for one user group may be transmitted instead of a wakeup packet for one user.
  • the wakeup packet When the wakeup packet is broadcast, the wakeup packet may be transmitted to all users through the first subband, the second subband, or the third subband. In each subband, a wakeup packet for all users may be transmitted, instead of a wakeup packet for one user.
  • the transmitter may transmit a wakeup packet index.
  • the wakeup packet index may indicate a subcarrier index for the first subband, the second subband, or the third subband to be used by each user.
  • phase rotation may be applied not only to a tone plan but also to a sequence constituting each subband according to the corresponding tone plan.
  • the first subband may be configured as a sequence in which a phase rotation value a1 is applied to the predetermined M sequence.
  • the second subband may be configured as a sequence in which a phase rotation value a2 is applied to the predetermined M sequence.
  • the third subband may be configured as a sequence in which a phase rotation value a3 is applied to the predetermined M sequence.
  • A1 may be 1, a2 may be -j, and a3 may be 1.
  • a1 may be -1, a2 may be j, and a3 may be -1.
  • a1 may be j, a2 may be 1, and a3 may be j.
  • a1 may be -j, a2 may be -1, and a3 may be -j.
  • the subband within the 20 MHz band can be partially allocated to the user. Therefore, even if a tone plan is set for each subband for multiple users, the wakeup packet can be transmitted only to a specific subband to a specific user.
  • both coefficients of the subcarrier constituting the second subband and the subcarrier constituting the third subband may be set to zero. . That is, the second subband and the third subband may not be assigned to any user. In this case, the phase rotation value a1 may be applied to the first subband as it is.
  • the coefficients of the subcarriers constituting the first subband and the subcarriers constituting the third subband are both set to zero.
  • the first subband and the third subband may not be assigned to any user.
  • the phase rotation value a2 may be applied to the second subband as it is.
  • the coefficients of the subcarriers constituting the first subband and the subcarriers constituting the second subband are all zero. Can be set. That is, the first subband and the second subband may not be assigned to any user. In this case, the phase rotation value a3 may be applied to the third subband as it is.
  • the coefficients of the subcarriers constituting the third subband may be all set to zero. That is, the third subband may not be assigned to any user.
  • the phase rotation value a1 may be applied to the first subband as it is, and the phase rotation value a2 may be applied to the second subband.
  • the coefficients of the subcarriers constituting the first subband may be all set to zero. That is, the first subband may not be assigned to any user.
  • the phase rotation value a2 may be applied to the second subband as it is, and the phase rotation value a3 may be applied to the third subband.
  • the coefficients of the subcarriers constituting the second subband may be all set to zero. That is, the second subband may not be assigned to any user.
  • the phase rotation value a1 may be applied to the first subband as it is, and the phase rotation value a3 may be applied to the third subband.
  • the 20 MHz band includes a first guard subcarrier, a subcarrier constituting the first subband, a first null subcarrier, a subcarrier constituting the second subband, and a second Guard subcarrier order.
  • the first guard subcarrier may include 13 subcarriers
  • the second guard subcarrier may include 12 subcarriers
  • the first null subcarrier may include 13 subcarriers. Since there are two multi-users, each user-specific subband may include a first subband and a second subband (total two user-specific subbands). Similarly, each of the subcarriers constituting the first subband and the subcarriers constituting the second subband may include thirteen subcarriers.
  • the manner in which the subcarriers for the wakeup packet are arranged in the 20 MHz band when the at least one subband is two may be represented as [13 13 13 13 12].
  • a wakeup packet may be transmitted by mapping a user to each of the two subbands. All of the subbands may be used or only a portion of the subbands may be used depending on the number of users transmitting the wakeup packet.
  • the wakeup packet When the wakeup packet is transmitted to two users, the wakeup packet may be transmitted to each of the two users on the first subband and the second subband. Since there are two users receiving the wakeup packet, both subbands can be used.
  • the wakeup packet When the wakeup packet is transmitted to one user, the wakeup packet may be transmitted to the one user through one subband of the first subband and the second subband. Since only one user receives the wakeup packet, some (only one) of the two subbands may be used.
  • the wakeup packet when the wakeup packet is transmitted to the user group, the wakeup packet may be transmitted to the user group through the first subband or the second subband. In each subband, a wakeup packet for one user group may be transmitted instead of a wakeup packet for one user.
  • the wakeup packet When the wakeup packet is broadcast, the wakeup packet may be transmitted to all users on the first subband or the second subband. In each subband, a wakeup packet for all users may be transmitted, instead of a wakeup packet for one user.
  • phase rotation may be applied not only to a tone plan but also to a sequence constituting each subband according to the corresponding tone plan.
  • the first subband may be configured as a sequence in which a phase rotation value a1 is applied to the predetermined M sequence.
  • the second subband may be configured as a sequence in which a phase rotation value a2 is applied to the predetermined M sequence.
  • A1 may be 1 and a2 may be 1.
  • a1 may be -1 and a2 may be -1.
  • a1 may be j and a2 may be j.
  • a1 may be -j and a2 may be -j.
  • the subband within the 20 MHz band can be partially allocated to the user. Therefore, even if a tone plan is set for each subband for multiple users, the wakeup packet can be transmitted only to a specific subband to a specific user.
  • the coefficients of the subcarriers constituting the second subband may be all set to zero. That is, the second subband may not be assigned to any user.
  • the phase rotation value a1 may be applied to the first subband as it is.
  • the coefficients of the subcarriers constituting the first subband may be all set to zero. That is, the first subband may not be assigned to any user.
  • the phase rotation value a2 may be applied to the second subband as it is.
  • the transmitter may transmit a wakeup packet index.
  • the wakeup packet index may indicate a subcarrier index for the first subband or the second subband to be used by each user.
  • the subcarrier index may be indicated in advance in the main radio terminal instead of the wakeup packet. This allows an accurate indication of which user the subcarrier for each wakeup packet is assigned to.
  • the off signal may be transmitted through a second symbol generated by applying a second sequence to 13 consecutive subcarriers in the 20 MHz band and performing a 64-point IFFT.
  • the first sequence and the second sequence may be different from each other.
  • the coefficients of all subcarriers may be set to zero.
  • the thirteen subcarriers may correspond to a partial band of the 20 MHz band.
  • 20 MHz is referred to as a reference band
  • 13 subcarriers may correspond to about 4.06 MHz band. That is, a specific sequence (first sequence or second sequence) is set only to 13 subcarriers selected as samples, and all other subcarriers except 13 subcarriers are set to 0. That is, it can be said that power is provided only for 4.06MHz in the 20MHz band in the frequency domain.
  • the subcarrier spacing of each of the 13 subcarriers may be 312.5 KHz.
  • the first symbol and the second symbol may have a length of 0.4us.
  • the transmitting apparatus may first recognize power values of the on signal and the off signal, and configure first information and second information.
  • the receiver decodes the first information and the second information by using an envelope detector, thereby reducing power consumed in decoding.
  • FIG. 12 is a block diagram illustrating a wireless device to which the present embodiment can be applied.
  • the wireless device may be an AP or a non-AP station (STA) as an STA capable of implementing the above-described embodiment.
  • the wireless device may correspond to the above-described user or may correspond to a transmission device for transmitting a signal to the user.
  • the AP 1200 includes a processor 1210, a memory 1220, and an RF unit 1230.
  • the RF unit 1230 may be connected to the processor 1210 to transmit / receive a radio signal.
  • the processor 1210 may implement the functions, processes, and / or methods proposed herein.
  • the processor 1210 may perform an operation according to the above-described embodiment. That is, the processor 1210 may perform an operation that may be performed by the AP during the operations disclosed in the embodiments of FIGS. 1 to 11.
  • the non-AP STA 1250 includes a processor 1260, a memory 1270, and an RF unit 1280.
  • the RF unit 1280 may be connected to the processor 1260 to transmit / receive a radio signal.
  • the processor 1260 may implement the functions, processes, and / or methods proposed in this embodiment.
  • the processor 1260 may be implemented to perform the non-AP STA operation according to the present embodiment described above.
  • the processor may perform the operation of the non-AP STA in the embodiment of FIGS. 1 to 11.
  • Processors 1210 and 1260 may include application-specific integrated circuits (ASICs), other chipsets, logic circuits, data processing devices, and / or converters for interconverting baseband signals and wireless signals.
  • the memories 1220 and 1270 may include read-only memory (ROM), random access memory (RAM), flash memory, memory cards, storage media, and / or other storage devices.
  • the RF unit 1230 and 1280 may include one or more antennas for transmitting and / or receiving a wireless signal.
  • the above-described technique may be implemented as a module (process, function, etc.) for performing the above-described function.
  • the module may be stored in the memories 1220 and 1270 and executed by the processors 1210 and 1260.
  • the memories 1220 and 1270 may be inside or outside the processors 1210 and 1260, and may be connected to the processors 1210 and 1260 by various well-known means.

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

Abstract

La présente invention concerne un procédé et un dispositif de transmission, à plusieurs utilisateurs, d'un paquet de réveil dans un système LAN sans fil. En particulier, un dispositif de transmission configure un paquet de réveil et transmet celui-ci à plusieurs utilisateurs. Le paquet de réveil comprend une séquence comprenant des premières et des deuxièmes informations par application d'un procédé OOK. Les premières informations sont configurées avec un signal de marche, et les deuxièmes informations sont configurées avec un signal d'arrêt. Le signal de marche est transféré par le biais d'un premier symbole généré par application d'une première séquence à 13 sous-porteuses successives dans la bande de 20 MHz et par réalisation d'une transformée IFFT de 64 points sur lesdites sous-porteuses. Le paquet de réveil est transmis par l'intermédiaire de sous-bandes à l'intérieur de la bande de 20 MHz. Les sous-bandes sont attribuées en un nombre similaire à celui des multiples utilisateurs. Les sous-bandes sont configurées avec une séquence obtenue par application d'une rotation de phase sur une séquence M prédéterminée.
PCT/KR2017/013913 2016-12-05 2017-11-30 Procédé et dispositif de transmission de paquet de réveil dans un système lan sans fil WO2018105950A1 (fr)

Applications Claiming Priority (8)

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US201662429870P 2016-12-05 2016-12-05
US62/429,870 2016-12-05
US201762465847P 2017-03-02 2017-03-02
US62/465,847 2017-03-02
US201762505987P 2017-05-15 2017-05-15
US62/505,987 2017-05-15
US201762524616P 2017-06-26 2017-06-26
US62/524,616 2017-06-26

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US20160278013A1 (en) * 2015-03-20 2016-09-22 Qualcomm Incorporated Phy for ultra-low power wireless receiver
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