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WO2018159945A1 - 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
WO2018159945A1
WO2018159945A1 PCT/KR2018/001482 KR2018001482W WO2018159945A1 WO 2018159945 A1 WO2018159945 A1 WO 2018159945A1 KR 2018001482 W KR2018001482 W KR 2018001482W WO 2018159945 A1 WO2018159945 A1 WO 2018159945A1
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Prior art keywords
subband
signal
sequence
zeros
subcarriers
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PCT/KR2018/001482
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English (en)
Korean (ko)
Inventor
박은성
임동국
조한규
최진수
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엘지전자 주식회사
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Publication of WO2018159945A1 publication Critical patent/WO2018159945A1/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
    • 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. Transmission Power Control [TPC] or power classes
    • H04W52/02—Power saving arrangements
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
    • Y02D30/00—Reducing energy consumption in communication networks
    • Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks

Definitions

  • the present disclosure relates to a technique for performing low power communication in a WLAN system, and more particularly, to a method and apparatus for transmitting a wake-up packet by applying a OOK scheme in a WLAN system.
  • next-generation WLANs 1) enhancements to the Institute of Electronics and Electronics Engineers (IEEE) 802.11 physical physical access (PHY) and medium access control (MAC) layers in the 2.4 GHz and 5 GHz bands, and 2) spectral efficiency and area throughput. aims to improve performance in real indoor and outdoor environments, such as in environments where interference sources exist, dense heterogeneous network environments, and high user loads.
  • IEEE Institute of Electronics and Electronics Engineers
  • PHY physical physical access
  • MAC medium access control
  • next-generation WLAN The environment mainly considered in the next-generation WLAN is a dense environment having many access points (APs) and a station (STA), and improvements in spectral efficiency and area throughput are discussed in such a dense environment.
  • next generation WLAN there is an interest in improving practical performance not only in an indoor environment but also in an outdoor environment, which is not much considered in a conventional WLAN.
  • next-generation WLAN there is a great interest in scenarios such as wireless office, smart home, stadium, hotspot, building / apartment, and AP based on the scenario.
  • STA are discussing about improving system performance in a dense environment with many STAs.
  • next-generation WLAN In addition, in the next-generation WLAN, there will be more discussion about improving system performance in outdoor overlapping basic service set (OBSS) environment, improving outdoor environment performance, and cellular offloading, rather than improving single link performance in one basic service set (BSS). It is expected.
  • the directionality of these next-generation WLANs means that next-generation WLANs will increasingly have a technology range similar to that of mobile communications. Considering the recent situation in which mobile communication and WLAN technology are discussed together in the small cell and direct-to-direct (D2D) communication area, the technical and business convergence of next-generation WLAN and mobile communication is expected to become more active.
  • D2D direct-to-direct
  • the present specification proposes a method and apparatus for transmitting a wake-up packet by applying a OOK scheme in a WLAN system.
  • An example of the present specification proposes a method and apparatus for transmitting a wake-up packet through at least one subband in a WLAN system.
  • This embodiment is performed in the transmitter, and the user may correspond to the 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.
  • Tones correspond to subcarriers, and hereinafter, tones and subcarriers are used interchangeably.
  • the transmitter configures a wake-up packet to which an OOK (On-Off Keying) scheme is applied.
  • OOK On-Off Keying
  • the transmitter transmits the wakeup packet.
  • the wakeup packet includes an on signal and an off signal.
  • the on signal is 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). Coefficients may be inserted in all 13 subcarriers. In addition, coefficients may be inserted in units of two subcarriers in the thirteen subcarriers, and zero may be inserted in the remaining subcarriers.
  • IFFT Inverse Fast Fourier Transform
  • the first sequence may be determined as a predetermined sequence.
  • the first sequence is a 13-bit long sequence and is defined as ⁇ 1,0, -1,0,1,0,0,0, -1,0, -1,0, -1 ⁇ . According to the first sequence, it can be seen that the coefficients are inserted in units of two subcarriers in the 13 subcarriers, so that the on signal may be a 3.2us signal having a period of 1.6us.
  • the wakeup packet is transmitted on at least one subband in the 20MHz band.
  • the subbands should be allocated at least as many as the number of users. For example, to construct a wakeup packet for four users, at least four subbands must be allocated. To construct a wakeup packet for three users, at least three subbands must be allocated. To construct a wakeup packet for two users, at least two subbands must be allocated. In this case, the subband is composed of the 13 subcarriers. In addition, even though a subband is allocated, it may not be used by a specific user, which will be described later.
  • the at least one subband is composed of a sequence in which phase rotation is applied to the first sequence.
  • the first sequence may be determined as a predetermined sequence.
  • the first sequence is a 13-bit long sequence and is defined as ⁇ 1,0, -1,0,1,0,0,0, -1,0, -1,0, -1 ⁇ . Since the coefficient 0 is inserted into the center subcarrier, the first sequence may correspond to the sequence in which the DC subcarrier is considered.
  • a subband for each user may be configured using a sequence considering a DC subcarrier.
  • 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 at least one subband is two, three, or four, it can be described as to which subcarrier (or subband) a wake-up packet is transmitted in 20 MHz as follows.
  • the 20 MHz band may include 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. . That is, the subcarrier indices may be allocated in order from the low subcarrier to the high subcarrier. This applies equally to the case where the number of subbands allocated is different.
  • the first guard subcarrier may include 13 subcarriers
  • the second guard subcarrier may include 12 subcarriers
  • the first null subcarrier may include 13 subcarriers. That is, the manner in which the subcarriers for the wake-up 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].
  • the first subband may be configured as a sequence in which a phase rotation value a1 is applied to the first sequence.
  • the second subband may be configured as a sequence in which a phase rotation value a2 is applied to the first 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, or a1 may be -j and a2 may be j. .
  • 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 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 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 20 MHz band includes a first guard subcarrier, a subcarrier constituting the first subband, a first null subcarrier, a subcarrier constituting the second subband,
  • the second null subcarrier, the subcarrier constituting the third subband, and the second guard subcarrier may be configured in this order.
  • 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. Therefore, 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].
  • the first subband may be configured as a sequence in which a phase rotation value a1 is applied to the first sequence.
  • the second subband may be configured as a sequence in which a phase rotation value a2 is applied to the first sequence.
  • the third subband may be configured of a sequence in which a phase rotation value a3 is applied to the first sequence.
  • A1 is 1, a2 is j, and a3 is 1, a1 is -1, a2 is -j, and a3 is -1, a1 is j, a2 is -1, and a3 may be j, or a1 may be -j, a2 may be 1, and a3 may be -j.
  • 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.
  • 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 and third subbands 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.
  • both coefficients of the subcarrier constituting the first subband and the subcarrier constituting the third subband may be set to zero. . That is, the first and third subbands may not be assigned to any user. In this case, the phase rotation value a2 may be applied to the second subband as it is.
  • both coefficients of the subcarrier constituting the first subband and the subcarrier constituting the second subband may be set to zero. . That is, the first and second subbands 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 20 MHz band includes a first guard subcarrier, a subcarrier constituting the first subband, a first null subcarrier, and a subcarrier constituting the second subband.
  • the first guard subcarrier includes three subcarriers
  • the second guard subcarrier includes two subcarriers
  • the first null subcarrier includes two subcarriers
  • the second null subcarrier may include three subcarriers
  • the third null subcarrier may include two subcarriers. Therefore, a method of arranging subcarriers for wake-up packets in a 20 MHz band when the at least one subband is 4 may be represented as [3 13 2 13 3 13 2 13 2].
  • the first subband may be configured as a sequence in which a phase rotation value a1 is applied to the first sequence.
  • the second subband may be configured as a sequence in which a phase rotation value a2 is applied to the first sequence.
  • the third subband may be configured of a sequence in which a phase rotation value a3 is applied to the first sequence.
  • the fourth subband may be configured of a sequence in which a phase rotation value a4 is applied to the first sequence.
  • A1 is 1, a2 is j, a3 is j, and a4 is 1, a1 is -1, a2 is -j, a3 is -j, and a4 is -1, or a1 May be j, the a2 may be -1, the a3 may be -1, and the a4 may be j, or the a1 may be -j, the a2 may be 1, the a3 may be 1, and the a4 may be -j.
  • a wakeup packet may be transmitted by mapping a user to each of the four 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 is transmitted to four users, the wakeup packet is transmitted to each of the four users on the first subband, the second subband, the third subband, and the fourth subband. Can be. Since four users receive the wakeup packet, all four subbands can be used.
  • the wakeup packet When the wakeup packet is transmitted to three users, the wakeup packet is transmitted through the three subbands of the first subband, the second subband, the third subband, and the fourth subband. May be sent to each of the users. Since there are three users receiving wake-up packets, some of the four subbands (only three) can be used.
  • the wakeup packet When the wakeup packet is transmitted to two users, the wakeup packet is transmitted through two subbands of the first subband, the second subband, the third subband, and the fourth subband. May be sent to each of the users. Since there are two users receiving wake-up packets, some of the four subbands (only two) can be used.
  • the wakeup packet When the wakeup packet is transmitted to one user, the wakeup packet is transmitted through one subband of one of the first subband, the second subband, the third subband, and the fourth subband. May be sent to up to one user. Since only one user receives the wakeup packet, some of the four subbands (only one) can be used.
  • the coefficients of the subcarriers constituting the second subband may be all set to zero. have. That is, the second subband may not be assigned to any user.
  • the phase rotation value a1 is applied to the first subband as it is
  • the phase rotation value a3 is applied to the third subband
  • the phase rotation value a4 is applied to the fourth subband.
  • the wakeup packet is configured and transmitted by applying the OOK modulation scheme in the transmitter to reduce power consumption by using an envelope detector during wakeup decoding in the receiver. Therefore, the receiving device can decode the wakeup packet to the minimum power.
  • the transmitter configures a subband for up to four users in the 20 MHz band to transmit the wakeup packet, thereby minimizing the interference between adjacent bands while minimizing the interference between the 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.
  • FIG. 11 illustrates various examples of a symbol repetition technique of repeating n symbols according to the present embodiment.
  • FIG. 13 is a flowchart illustrating a procedure of transmitting a wake-up packet through at least one subband according to the present embodiment.
  • FIG. 14 is a block diagram illustrating a wireless device to which the present embodiment can be applied.
  • 15 is a block diagram illustrating an example of an apparatus included in a processor.
  • WLAN wireless local area network
  • BSS infrastructure basic service set
  • IEEE Institute of Electrical and Electronic Engineers
  • the WLAN system may include one or more infrastructure BSSs 100 and 105 (hereinafter, BSS).
  • BSSs 100 and 105 are a set of APs and STAs such as an access point 125 and a STA1 (station 100-1) capable of successfully synchronizing and communicating with each other, and do not indicate a specific area.
  • the BSS 105 may include one or more joinable STAs 105-1 and 105-2 to one AP 130.
  • the BSS may include at least one STA, APs 125 and 130 for providing a distribution service, and a distribution system (DS) 110 for connecting a plurality of APs.
  • STA STA
  • APs 125 and 130 for providing a distribution service
  • DS distribution system
  • the distributed system 110 may connect several BSSs 100 and 105 to implement an extended service set (ESS) 140 which is an extended service set.
  • ESS 140 may be used as a term indicating one network in which one or several APs 125 and 230 are connected through the distributed system 110.
  • APs included in one ESS 140 may have the same service set identification (SSID).
  • the portal 120 may serve as a bridge for connecting the WLAN network (IEEE 802.11) with another network (for example, 802.X).
  • a network between the APs 125 and 130 and a network between the APs 125 and 130 and the STAs 100-1, 105-1 and 105-2 may be implemented. However, it may be possible to perform communication by setting up a network even between STAs without the APs 125 and 130.
  • a network that performs communication by establishing a network even between STAs without APs 125 and 130 is defined as an ad-hoc network or an independent basic service set (BSS).
  • FIG. 1 is a conceptual diagram illustrating an IBSS.
  • the IBSS is a BSS operating in an ad-hoc mode. Since IBSS does not contain an AP, there is no centralized management entity. That is, in the IBSS, the STAs 150-1, 150-2, 150-3, 155-4, and 155-5 are managed in a distributed manner. In the IBSS, all STAs 150-1, 150-2, 150-3, 155-4, and 155-5 may be mobile STAs, and access to a distributed system is not allowed, thus making a self-contained network. network).
  • a STA is any functional medium that includes medium access control (MAC) conforming to the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard and a physical layer interface to a wireless medium. May be used to mean both an AP and a non-AP STA (Non-AP Station).
  • MAC medium access control
  • IEEE Institute of Electrical and Electronics Engineers
  • the STA may include a mobile terminal, a wireless device, a wireless transmit / receive unit (WTRU), a user equipment (UE), a mobile station (MS), a mobile subscriber unit ( It may also be called various names such as a mobile subscriber unit or simply a user.
  • WTRU wireless transmit / receive unit
  • UE user equipment
  • MS mobile station
  • UE mobile subscriber unit
  • It may also be called various names such as a mobile subscriber unit or simply a user.
  • the term "user” may be used in various meanings, for example, may also be used to mean an STA participating in uplink MU MIMO and / or uplink OFDMA transmission in wireless LAN communication. It is not limited to this.
  • FIG. 2 is a diagram illustrating an example of a PPDU used in the IEEE standard.
  • PPDUs PHY protocol data units
  • LTF and STF fields included training signals
  • SIG-A and SIG-B included control information for the receiving station
  • data fields included user data corresponding to the PSDU.
  • This embodiment proposes an improved technique for the signal (or control information field) used for the data field of the PPDU.
  • the signal proposed in this embodiment may be applied on a high efficiency PPDU (HE PPDU) according to the IEEE 802.11ax standard. That is, the signals to be improved in the present embodiment may be HE-SIG-A and / or HE-SIG-B included in the HE PPDU. Each of HE-SIG-A and HE-SIG-B may also be represented as SIG-A or SIG-B.
  • the improved signal proposed by this embodiment is not necessarily limited to the HE-SIG-A and / or HE-SIG-B standard, and controls / control of various names including control information in a wireless communication system for transmitting user data. Applicable to data fields.
  • FIG. 3 is a diagram illustrating an example of a HE PPDU.
  • the control information field proposed in this embodiment may be HE-SIG-B included in the HE PPDU as shown in FIG. 3.
  • the HE PPDU according to FIG. 3 is an example of a PPDU for multiple users.
  • the HE-SIG-B may be included only for the multi-user, and the HE-SIG-B may be omitted in the PPDU for the single user.
  • a HE-PPDU for a multiple user includes a legacy-short training field (L-STF), a legacy-long training field (L-LTF), a legacy-signal (L-SIG), High efficiency-signal A (HE-SIG-A), high efficiency-signal-B (HE-SIG-B), high efficiency-short training field (HE-STF), high efficiency-long training field (HE-LTF) It may include a data field (or MAC payload) and a PE (Packet Extension) field. Each field may be transmitted during the time period shown (ie, 4 or 8 ms, etc.).
  • the PPDU used in the IEEE standard is mainly described as a PPDU structure transmitted over a channel bandwidth of 20 MHz.
  • the PPDU structure transmitted on a bandwidth wider than the channel bandwidth of 20 MHz may be a structure in which linear scaling of the PPDU structure used in the channel bandwidth of 20 MHz is applied.
  • the PPDU structure used in the IEEE standard is generated based on 64 Fast Fourier Tranforms (FTFs), and a CP portion (cyclic prefix portion) may be 1/4.
  • FFTs Fast Fourier Tranforms
  • CP portion cyclic prefix portion
  • the length of the effective symbol interval (or FFT interval) may be 3.2us
  • the CP length is 0.8us
  • the symbol duration may be 4us (3.2us + 0.8us) plus the effective symbol interval and the CP length.
  • Wireless networks are ubiquitous, usually indoors and often installed outdoors. Wireless networks use various techniques to send and receive information. For example, but not limited to, two widely used technologies for communication are those that comply with IEEE 802.11 standards such as the IEEE 802.11n standard and the IEEE 802.11ac standard.
  • the IEEE 802.11 standard specifies a common Medium Access Control (MAC) layer that provides a variety of features to support the operation of IEEE 802.11-based wireless LANs (WLANs).
  • the MAC layer utilizes protocols that coordinate access to shared radios and improve communications over wireless media, such as IEEE 802.11 stations (such as a PC's wireless network card (NIC) or other wireless device or station (STA) and access point ( Manage and maintain communication between APs).
  • IEEE 802.11 stations such as a PC's wireless network card (NIC) or other wireless device or station (STA) and access point ( Manage and maintain communication between APs).
  • IEEE 802.11ax is the successor to 802.11ac and has been proposed to improve the efficiency of WLAN networks, especially in high density areas such as public hotspots and other high density traffic areas.
  • IEEE 802.11 can also use Orthogonal Frequency Division Multiple Access (OFDMA).
  • OFDMA Orthogonal Frequency Division Multiple Access
  • the High Efficiency WLAN Research Group (HEW SG) within the IEEE 802.11 Work Group is dedicated to improving system throughput / area in high-density scenarios of APs (access points) and / or STAs (stations) in relation to the IEEE 802.11 standard. We are considering improving efficiency.
  • Wearable devices and small computing devices such as sensors and mobile devices are constrained by small battery capacities, but use wireless communication technologies such as Wi-Fi, Bluetooth®, and Bluetooth® Low Energy (BLE). Support, connect to and exchange data with other computing devices such as smartphones, tablets, and computers. Since these communications consume power, it is important to minimize the energy consumption of such communications in these devices.
  • One ideal strategy to minimize energy consumption is to power off the communication block as frequently as possible while maintaining data transmission and reception without increasing delay too much. That is, the communication block is transmitted immediately before the data reception, and only when there is data to wake up, the communication block is turned on and the communication block is turned off for the remaining time.
  • LP-WUR low-power wake-up receiver
  • the communication system (or communication subsystem) described herein includes a main radio (802.11) and a low power wake up receiver.
  • the main radio is used for transmitting and receiving user data.
  • the main radio is turned off if there are no data or packets to transmit.
  • the low power wake-up receiver wakes up the main radio when there is a packet to receive. At this time, the user data is transmitted and received by the main radio.
  • the low power wake-up receiver is not for user data. It is simply a receiver to wake up the main radio. In other words, the transmitter is not included.
  • the low power wake-up receiver is active while the main radio is off.
  • Low power wake-up receivers target a target power consumption of less than 1 mW in an active state.
  • low power wake-up receivers use a narrow bandwidth of less than 5 MHz.
  • the target transmission range of the low power wake-up receiver is the same as that of the existing 802.11.
  • 4 illustrates a low power wake-up receiver in an environment in which data is not received.
  • 5 illustrates a low power wake-up receiver in an environment in which data is received.
  • one way to implement an ideal transmission and reception strategy is a main radio such as Wi-Fi, Bluetooth® radio, or Bluetooth® Radio (BLE). Adding a low power wake-up receiver (LP-WUR) that can wake up.
  • LP-WUR low power wake-up receiver
  • the Wi-Fi / BT / BLE 420 is turned off and the low power wake-up receiver 430 is turned on without receiving data.
  • LP-WUR low power wake-up receiver
  • the low power wakeup receiver 530 may receive the entire Wi-Fi / BT / BLE radio 520 so that the data packet following the wakeup packet can be correctly received. Wake up). In some cases, however, actual data or IEEE 802.11 MAC frames may be included in the wakeup packet. In this case, it is not necessary to wake up the entire Wi-Fi / BT / BLE radio 520, but only a part of the Wi-Fi / BT / BLE radio 520 to perform the necessary process. This can result in significant power savings.
  • One example technique disclosed herein defines a method for a granular wakeup mode for Wi-Fi / BT / BLE using a low power wakeup receiver. For example, the actual data contained in the wakeup packet can be passed directly to the device's memory block without waking up the Wi-Fi / BT / BLE radio.
  • a wakeup packet contains an IEEE 802.11 MAC frame
  • only the MAC processor of the Wi-Fi / BT / BLE wireless device needs to wake up to process the IEEE 802.11 MAC frame included in the wakeup. That is, the PHY module of the Wi-Fi / BT / BLE radio can be turned off or kept in a low power mode.
  • Wi-Fi / BT / BLE radios that use low power wake-up receivers, requiring that the Wi-Fi / BT / BLE radio be powered on when a wake-up packet is received.
  • only necessary parts (or components) of the Wi-Fi / BT / BLE radio can be selectively woken up, thereby saving energy and reducing the waiting time.
  • Many solutions that use low-power wake-up receivers to receive wake-up packets wake up the entire Wi-Fi / BT / BLE radio.
  • One exemplary aspect discussed herein wakes up only the necessary portions of the Wi-Fi / BT / BLE radio required to process the received data, saving significant amounts of energy and reducing unnecessary latency in waking up the main radio. Can be.
  • the low power wake-up receiver 530 may wake up the main radio 520 based on the wake-up packet transmitted from the transmitter 500.
  • the transmitter 500 may be set to transmit a wakeup packet to the receiver 510.
  • the low power wake-up receiver 530 may be instructed to wake up the main radio 520.
  • FIG. 6 shows an example of a wakeup packet structure according to the present embodiment.
  • the wakeup packet may include one or more legacy preambles.
  • One or more legacy devices may decode or process the legacy preamble.
  • the wakeup packet may include a payload after the legacy preamble.
  • the payload may be modulated by a simple modulation scheme, for example, an On-Off Keying (OOK) modulation scheme.
  • OOK On-Off Keying
  • the transmitter may be configured to generate and / or transmit a wakeup packet 600.
  • the receiving device may be configured to process the received wakeup packet 600.
  • the wakeup packet 600 may include a legacy preamble or any other preamble 610 as defined by the IEEE 802.11 specification.
  • the wakeup packet 600 may include a payload 620.
  • Legacy preambles provide coexistence with legacy STAs.
  • the legacy preamble 610 for coexistence uses the L-SIG field to protect the packet.
  • the 802.11 STA may detect the start of a packet through the L-STF field in the legacy preamble 610.
  • the 802.11 STA can know the end of the packet through the L-SIG field in the legacy preamble 610.
  • a BPSK modulated symbol after the L-SIG a false alarm of an 802.11n terminal can be reduced.
  • One symbol (4us) modulated with BPSK also has a 20MHz bandwidth like the legacy part.
  • the legacy preamble 610 is a field for third party legacy STAs (STAs not including LP-WUR).
  • the legacy preamble 610 is not decoded from the LP-WUR.
  • the payload 620 may include a wakeup preamble 622.
  • Wake-up preamble 622 may include a sequence of bits configured to identify wake-up packet 600.
  • the wakeup preamble 622 may include, for example, a PN sequence.
  • the payload 620 may include a MAC header 624 including address information of a receiver receiving the wakeup packet 600 or an identifier of the receiver.
  • the payload 620 may include a frame body 626 that may include other information of the wakeup packet.
  • the frame body 626 may include length or size information of the payload.
  • the payload 620 may include a Frame Check Sequence (FCS) field 628 that includes a Cyclic Redundancy Check (CRC) value.
  • FCS Frame Check Sequence
  • CRC Cyclic Redundancy Check
  • it may include a CRC-8 value or a CRC-16 value of the MAC header 624 and the frame body 626.
  • FIG. 7 shows a signal waveform of a wakeup packet according to the present embodiment.
  • the wakeup packet 700 includes a legacy preamble (802.11 preamble, 710) and a payload modulated by OOK. That is, the legacy preamble and the new LP-WUR signal waveform coexist.
  • the legacy preamble 710 may be modulated according to the OFDM modulation scheme. That is, the legacy preamble 710 is not applied to the OOK method.
  • the payload may be modulated according to the OOK method.
  • the wakeup preamble 722 in the payload may be modulated according to another modulation scheme.
  • the payload may be transmitted on a channel bandwidth of about 4.06 MHz. This will be described later in the OOK pulse design method.
  • FIG. 8 is a diagram for describing a principle in which power consumption is determined according to a ratio of 1 and 0 of bit values constituting binary sequence information using the OOK method.
  • OOK modulation can be performed. That is, in consideration of the bit values of the binary sequence information, it is possible to perform the communication of the OOK modulation method.
  • the light emitting diode is used for visible light communication
  • the light emitting diode is turned on when the bit value constituting the binary sequence information is 1, and the light emitting diode is turned off when the bit value is 0.
  • the light emitting diode can be made to blink.
  • the receiver receives and restores data transmitted in the form of visible light, thereby enabling communication using visible light.
  • the blinking of the light emitting diode cannot be perceived by the human eye, the person feels that the illumination is continuously maintained.
  • FIG. 8 information in the form of a binary sequence having 10 bit values is used.
  • FIG. 8 there is information in the form of a binary sequence having a value of '1001101011'.
  • the bit value is 1
  • the transmitter is turned on
  • the bit value is 0,
  • the transmitter is turned off
  • the symbol is turned on at 6 bit values out of 10 bit values.
  • the power consumption is 60% according to the duty cycle of FIG. 8.
  • the power consumption of the transmitter is determined according to the ratio of 1 and 0 constituting the binary sequence information.
  • the ratio of 1 and 0 which constitutes information in binary sequence form, must also be maintained.
  • the ratio of 1 and 0 constituting the information in the form of a binary sequence must also be maintained.
  • the receiver is mainly a wake-up receiver (WUR)
  • WUR wake-up receiver
  • the main reason for using OOK is that the power consumption is very low when decoding the received signal. Until the decoding is performed, there is no significant difference in power consumption in the main radio or WUR, but a large difference occurs in the decoding process. Below is the approximate power consumption.
  • the existing Wi-Fi power consumption is about 100mW.
  • power consumption of Resonator + Oscillator + PLL (1500uW)-> LPF (300uW)-> ADC (63uW)-> decoding processing (OFDM receiver) (100mW) may occur.
  • -WUR power consumption is about 1mW.
  • power consumption of Resonator + Oscillator (600uW)-> LPF (300uW)-> ADC (20uW)-> decoding processing (Envelope detector) (1uW) may occur.
  • the OFDM transmitter of 802.11 can be reused to generate OOK pulses.
  • the transmitter can generate a sequence having 64 bits by applying a 64-point IFFT as in 802.11.
  • the transmitter should generate the payload of the wakeup packet by modulating the OOK method.
  • the OOK method is applied to the ON-signal.
  • the on signal is a signal having an actual power value
  • the off signal corresponds to a signal having no actual power value.
  • the off signal is also applied to the OOK method, but the signal is not generated using the transmitter, and since no signal is actually transmitted, it is not considered in the configuration of the wakeup packet.
  • information (bit) 1 may be an on signal and information (bit) 0 may be an off signal.
  • information 1 may indicate a transition from an off signal to an on signal
  • information 0 may indicate a transition from an on signal to an off signal.
  • the information 1 may indicate the transition from the on signal to the off signal
  • the information 0 may indicate the transition from the off signal to the on signal. Manchester coding scheme will be described later.
  • the transmitter applies a sequence by selecting 13 consecutive subcarriers of a 20 MHz band as a reference band as a sample.
  • 13 subcarriers located among the subcarriers in the 20 MHz band are selected as samples. That is, a subcarrier whose subcarrier index is from -6 to +6 is selected from the 64 subcarriers.
  • the subcarrier index 0 may be nulled to 0 as the DC subcarrier.
  • subcarrier spacing is 312.5 KHz
  • 13 subcarriers have a channel bandwidth of about 4.06 MHz. That is, it can be said that power is provided only for 4.06MHz in the 20MHz band in the frequency domain.
  • SNR signal to noise ratio
  • the power consumption of the AC / DC converter of the receiver can be reduced.
  • the power consumption can be reduced by reducing the sampling frequency band to 4.06MHz.
  • the transmitter may generate one on-signal in the time domain by performing a 64-point IFFT on 13 subcarriers.
  • One on-signal has a size of 1 bit. That is, a sequence composed of 13 subcarriers may correspond to 1 bit.
  • the transmitter may not transmit the off signal at all.
  • IFFT a 3.2us symbol may be generated, and if a CP (Cyclic Prefix, 0.8us) is included, one symbol having a length of 4us may be generated. That is, one bit indicating one on-signal may be loaded in one symbol.
  • the reason for configuring and sending the bits as in the above-described embodiment is to reduce power consumption by using an envelope detector in the receiver. As a result, the receiving device can decode the packet with the minimum power.
  • the basic data rate for one information may be 125 Kbps (8us) or 62.5Kbps (16us).
  • each signal having a length of K in the 20 MHz band may be transmitted on K consecutive subcarriers of a total of 64 subcarriers. That is, K may correspond to the bandwidth of the OOK pulse by the number of subcarriers used to transmit a signal. All other coefficients of the K subcarriers are zero.
  • the indices of the K subcarriers used by the signal corresponding to the information 0 and the information 1 are the same.
  • the subcarrier index used may be represented as 33-floor (K / 2): 33 + ceil (K / 2) -1.
  • the information 1 and the information 0 may have the following values.
  • the alpha is a power normalization factor and may be, for example, 1 / sqrt (K).
  • FIG. 10 is an explanatory diagram of a Manchester coding scheme according to the present embodiment.
  • Manchester coding is a type of line coding, and may indicate information as shown in the following table in a manner in which a transition of a magnitude value occurs in the middle of one bit period.
  • Manchester coding means a method of converting data from 1 to 01, 0 to 10, 1 to 10, and 0 to 01.
  • Table 1 shows an example in which data is converted from 1 to 10 and 0 to 01 using Manchester coding.
  • bit string to be transmitted As shown in Fig. 10, the bit string to be transmitted, the Manchester coded signal, the clock reproduced on the receiving side, and the data reproduced on the clock are shown in order from top to bottom.
  • the transmitting side transmits data using the Manchester coding scheme
  • the receiving side reads the data a little later on the basis of the transition point transitioning from 1 ⁇ 0 or 0 ⁇ 1 and recovers the data, and then transitions to 1 ⁇ 0 or 0 ⁇ 1
  • the clock is recovered by recognizing the transition point as the clock transition point.
  • the symbol when the symbol is divided based on the transition point, it can be simply decoded by comparing the power at the front and the back at the center of the symbol.
  • the bit string to be transmitted is 10011101
  • the Manchester coded signal is 0110100101011001
  • the clock reproduced by the receiver recognizes the transition point of the Manchester coded signal as the transition point of the clock. Then, the data is recovered by using the reproduced clock.
  • this method can use the TXD pin for data transmission and the RXD pin for reception by using only the data transmission channel. Therefore, synchronized bidirectional transmission is possible.
  • This specification proposes various symbol types that can be used in the WUR and thus data rates.
  • a symbol coding based symbol coding technique and a symbol repetition technique may be used.
  • a symbol reduction technique may be used to obtain a high data rate.
  • each symbol may be generated using an existing 802.11 OFDM transmitter.
  • the number of subcarriers used to generate each symbol may be thirteen. However, it is not limited thereto.
  • each symbol may use OOK modulation formed of an ON-signal and an OFF-signal.
  • One symbol generated for the WUR may be composed of a CP (Cyclic Prefix or Guard Interval) and a signal part representing actual information. Symbols having various data rates may be designed by variously setting or repeating the lengths of the CP and the actual information signal.
  • CP Cyclic Prefix or Guard Interval
  • the basic WUR symbol may be represented as CP + 3.2us. That is, one bit is represented using a symbol having the same length as the existing Wi-Fi.
  • the transmitting apparatus applies a specific sequence to all available subcarriers (for example, 13 subcarriers) and then performs IFFT to form an information signal portion of 3.2 us.
  • a coefficient of 0 may be loaded on the DC subcarrier or the middle subcarrier index among all available subcarriers.
  • a 3.2us off signal can be generated by applying all coefficients to zero.
  • CP may be used by adopting a specific length from the rear of the information signal 3.2us immediately behind. At this time, CP may be 0.4us or 0.8us. This length is equal to the guard interval of 802.11ac.
  • one bit information corresponding to one basic WUR symbol may be represented as shown in the following table.
  • CP + 3.2us including CP may point to one 1-bit information. That is, the 3.2us on signal can be viewed as a (CP + 3.2us) on signal. A 3.2us off signal can be seen as a (CP + 3.2us) off signal.
  • a symbol to which Manchester coding is applied may be represented as CP + 1.6us + CP + 1.6us or CP + 1.6us + 1.6us.
  • the symbol to which the Manchester coding is applied may be generated as follows.
  • the time used for transmitting one bit (or symbol) except for the guard interval of the transmission signal is 3.2 us.
  • a signal size transition should occur at 1.6us. That is, each sub-information having a length of 1.6us should have a value of 0 or 1, and may configure a signal in the following manner.
  • Sub information 1 may have a value of beta * ones (1, K).
  • Beta is a power normalization factor and may be, for example, 1 / sqrt (ceil (K / 2)).
  • a specific sequence is applied in units of two squares to all available subcarriers (eg, 13 subcarriers) to generate a symbol to which Manchester coding is applied. That is, even-numbered subcarriers of a particular sequence are nulled to zero. That is, in a particular sequence, coefficients may exist at intervals of two cells.
  • a particular sequence with coefficients spaced two spaces apart is ⁇ a 0 b 0 c 0 d 0 e 0 f 0 g ⁇ , ⁇ 0 a 0 b 0 c 0 d 0 e 0 f 0 ⁇ or ⁇ a 0 b 0 c 0 0 0 d 0 e 0 method.
  • a, b, c, d, e, f, g is 1 or -1.
  • the transmitter maps a specific sequence to K consecutive subcarriers of 64 subcarriers (for example, 33-floor (K / 2): 33 + ceil (K / 2) -1) and the remaining subcarriers.
  • IFFT is performed by setting the coefficient to 0.
  • signals in the time domain can be generated.
  • the signal in the time domain is a 3.2us long signal having a 1.6us period because coefficients exist at intervals of two spaces in the frequency domain.
  • One of the first or second 1.6us period signals can be selected and used as sub information 1.
  • the sub information 0 may have a value of zeros (1, K).
  • the transmitter maps a specific sequence to K consecutive subcarriers of 64 subcarriers (eg, 33-floor (K / 2): 33 + ceil (K / 2) -1) and performs IFFT.
  • the signal in the time domain can be generated.
  • the sub information 0 may correspond to a 1.6us off signal.
  • the 1.6us off signal can be generated by setting all coefficients to zero.
  • One of the first or second 1.6us periodic signals of the signal in the time domain may be selected and used as the sub information 0. You can simply use the zeros (1,32) signal as subinformation zero.
  • information 1 is also divided into the first 1.6us (sub information 0) and the second 1.6us (sub information 1), a signal corresponding to each sub information may be configured in the same manner as the information 0 is generated.
  • the coexistence problem is a problem caused by transmitting a signal by determining that another device is a channel idle state due to a continuous off symbol. If only OOK modulation is used, for example, the off-symbol may be contiguous with the sequence 100001 or the like, but if Manchester coding is used, the off-symbol cannot be contiguous with the sequence 100101010110.
  • the sub information may be referred to as a 1.6us information signal.
  • the 1.6us information signal may be a 1.6us on signal or a 1.6 off signal.
  • the 1.6us on signal and the 1.6 off signal may have different sequences applied to each subcarrier.
  • CP can be used by adopting a specific length from the back of the 1.6us of the information signal immediately after. At this time, CP may be 0.4us or 0.8us. This length is equal to the guard interval of 802.11ac.
  • one bit information corresponding to one Manchester coded symbol may be represented as shown in the following table.
  • CP + 1.6us + CP + 1.6us or CP + 1.6us + 1.6us including CP may indicate one 1-bit information. That is, in the former case, the 1.6us on signal and the 1.6us off signal may be regarded as the (CP + 1.6us) on signal and the (CP + 1.6us) off signal.
  • the symbol repetition technique is applied to the wakeup payload 724.
  • the symbol repetition technique means repetition of a time signal after insertion of an IFFT and a cyclic prefix (CP) of each symbol.
  • CP cyclic prefix
  • Option 1 Information 0 and Information 1 can be repeatedly represented by the same symbol.
  • Option 2 Information 0 and Information 1 can be repeatedly represented by different symbols.
  • the transmitted signal may correspond to a wakeup packet, and a method of decoding the wakeup packet can be largely divided into two types.
  • the first is non-coherent detection and the second is coherent detection.
  • non-coherent detection the phase relationship between the transmitter and receiver signals is not fixed.
  • the receiver does not need to measure and adjust the phase of the received signal.
  • the coherent detection method requires that the phase of the signal between the transmitter and the receiver be aligned.
  • the receiver includes the low power wake-up receiver described above.
  • the low power wake-up receiver may decode a packet (wake-up packet) transmitted using an OOK modulation scheme using an envelope detector to reduce power consumption.
  • the envelope detector measures and decodes the power or magnitude of the received signal.
  • the receiver sets a threshold based on the power or magnitude measured by the envelope detector. When decoding the symbol to which the OOK is applied, it is determined as information 1 if it is greater than or equal to the threshold value, and as information 0 when it is smaller than the threshold value.
  • the method of decoding a symbol to which the symbol repetition technique is applied is as follows.
  • the receiving apparatus may use the wake-up preamble 722 to calculate a power when symbol 1 (symbol including information 1) is transmitted and determine the threshold.
  • the average power of the two symbols may be determined to determine information 1 (1 1) if the value is equal to or greater than the threshold value, and to determine information 0 (0 0) if the value is less than the threshold value.
  • information may be determined by comparing the power of two symbols without determining a threshold.
  • information 1 is composed of 0 1 and information 0 is composed of 1 0, it is determined as information 0 if the power of the first symbol is greater than the power of the second symbol. On the contrary, if the power of the first symbol is less than the power of the second symbol, it is determined as information 1.
  • the interleaver may be applied in units of specific symbol numbers below the packet unit.
  • n can be extended as follows. 11 illustrates various examples of a symbol repetition technique of repeating n symbols according to the present embodiment.
  • Option 1 Information 0 and information 1 may be repeatedly represented by the same symbol n times as shown in FIG.
  • information 0 and information 1 may be repeatedly represented by different symbols n times.
  • one half of a symbol may be configured as information 0 and the other half may be configured as information 1 to represent n symbols.
  • n symbols may be represented by dividing the number of symbols 1 (symbol including information 1) and the number of symbols 0 (symbol including information 0).
  • the interleaver may be applied in units of packets and specific symbols.
  • the receiving apparatus may determine whether the information is 0 or 1 by determining the threshold value and comparing the powers of the n symbols.
  • consecutive symbol 0 may cause a coexistence problem with an existing Wi-Fi device and / or another device.
  • the coexistence problem is a problem caused by transmitting a signal by determining that another device is a channel idle state due to a continuous off symbol.
  • the option 2 scheme may be preferred as it is desirable to avoid the use of consecutive off symbols to solve the leveling problem.
  • the first or last m is represented by 0 (OFF) or 1 (ON) symbols depending on the information, and the nm or 0 (OFF) or 1 (ON) redundant symbols are formed consecutively before or after. can do.
  • a code rate of 3/4 may be 1,010 or 010,1 or 0,010 or 010,0.
  • a code rate of 1/2 it may be desirable to apply a code rate of 1/2 or less.
  • the order of symbols can be reconstructed by the interleaver.
  • the interleaver may be applied in units of packets and specific symbols.
  • a symbol to which the symbol repetition technique is applied may be represented by n (CP + 3.2us) or CP + n (1.6us).
  • a 3.2us off signal can be generated by applying all coefficients to zero.
  • CP may be used by adopting a specific length from the rear of the information signal 3.2us immediately behind. At this time, CP may be 0.4us or 0.8us. This length is equal to the guard interval of 802.11ac.
  • 1 bit information corresponding to a symbol to which a general symbol repetition technique is applied may be represented as shown in the following table.
  • n pieces (CP + 3.2us) including CPs or CP + n pieces (3.2us) may indicate one 1-bit information. That is, in the case of n (CP + 3.2us), the 3.2us on signal may be viewed as a (CP + 3.2us) on signal, and the 3.2us off signal may be viewed as a (CP + 3.2us) off signal.
  • a symbol to which the symbol repetition technique is applied may be represented as CP + 3.2us + CP + 3.2us or CP + 3.2us + 3.2us.
  • two information signals are used to represent one bit and a specific sequence is applied to all available subcarriers (for example, thirteen), and then IFFT is taken to generate an information signal (symbol) of 3.2us.
  • a 3.2us off signal can be generated by applying all coefficients to zero.
  • CP may be used by adopting a specific length from the rear of the information signal 3.2us immediately behind. At this time, CP may be 0.4us or 0.8us. This length is equal to the guard interval of 802.11ac.
  • one bit information corresponding to a symbol to which the symbol repetition technique is applied may be represented as shown in the following table.
  • CP + 3.2us + CP + 3.2us or CP + 3.2us + 3.2us, including CP may point to one 1-bit information. That is, in the case of CP + 3.2us + CP + 3.2us, the 3.2us on signal can be viewed as a (CP + 3.2us) on signal, and the 3.2us off signal can be viewed as a (CP + 3.2us) off signal. .
  • a symbol to which the symbol repetition technique is applied may be represented as CP + 3.2us + CP + 3.2us + CP + 3.2us or CP + 3.2us + 3.2us + 3.2us.
  • three information signals are used to represent one bit and a specific sequence is applied to all available subcarriers (eg, thirteen), and then IFFT is taken to generate an information signal (symbol) of 3.2us.
  • a 3.2us off signal can be generated by applying all coefficients to zero.
  • CP may be used by adopting a specific length from the rear of the information signal 3.2us immediately behind. At this time, CP may be 0.4us or 0.8us. This length is equal to the guard interval of 802.11ac.
  • one bit information corresponding to a symbol to which the symbol repetition technique is applied may be represented as shown in the following table.
  • CP + 3.2us + CP + 3.2us + CP + 3.2us or CP + 3.2us + 3.2us + 3.2us, including CP may point to one 1-bit information. That is, in the case of CP + 3.2us + CP + 3.2us + CP + 3.2us + CP + 3.2us, the 3.2us on signal can be viewed as a (CP + 3.2us) on signal, and the 3.2us off signal is a (CP + 3.2us) off It can be seen as a signal.
  • a symbol to which the symbol repetition technique is applied may be represented as CP + 3.2us + CP + 3.2us + CP + 3.2us + CP + 3.2us or CP + 3.2us + 3.2us + 3.2us + 3.2us.
  • a 3.2us off signal can be generated by applying all coefficients to zero.
  • CP may be used by adopting a specific length from the rear of the information signal 3.2us immediately behind. At this time, CP may be 0.4us or 0.8us. This length is equal to the guard interval of 802.11ac.
  • one bit information corresponding to a symbol to which the symbol repetition technique is applied may be represented as shown in the following table.
  • Table 7 does not indicate CP separately. Indeed, CP + 3.2us + CP + 3.2us + CP + 3.2us + CP + 3.2us + CP + 3.2us or CP + 3.2us + 3.2us + 3.2us + 3.2us, including CP, may point to one single bit of information. That is, in the case of CP + 3.2us + CP + 3.2us + CP + 3.2us + CP + 3.2us + CP + 3.2us, the 3.2us on signal can be regarded as (CP + 3.2us) on signal and the 3.2us off signal is (CP + 3.2us) off signal.
  • a symbol to which Manchester coding is applied based on symbol repetition may be represented by n (CP + 1.6us + CP + 1.6us) or CP + n (1.6us + 1.6us).
  • IFFT 3.2us of signal with 1.6us period is generated. Take one of these and set it as a 1.6us information signal (symbol).
  • the sub information may be called a 1.6us information signal.
  • the 1.6us information signal may be a 1.6us on signal or a 1.6 off signal.
  • the 1.6us on signal and the 1.6 off signal may have different sequences applied to each subcarrier.
  • the 1.6us off signal can be generated by applying all coefficients to zero.
  • CP can be used by adopting a specific length from the back of the 1.6us of the information signal immediately after. At this time, CP may be 0.4us or 0.8us. This length is equal to the guard interval of 802.11ac.
  • 1 bit information corresponding to a symbol to which Manchester coding is applied based on the symbol repetition may be represented as shown in the following table.
  • n (CP + 1.6us + CP + 1.6us) or CP + n (1.6us + 1.6us) including CP may indicate one 1-bit information. That is, in the case of n (CP + 1.6us + CP + 1.6us), the 1.6us on signal can be viewed as a (CP + 1.6us) on signal, and the 1.6us off signal is a (CP + 1.6us) off signal. Can be seen as.
  • the symbol repetition technique can satisfy the range requirement of low power wake-up communication.
  • the data rate for one symbol is 250 Kbps (4us).
  • the data rate may be 125 Kbps (8us)
  • the fourth repetition is performed, the data rate may be 62.5 Kbps (16us)
  • the eight times are repeated, the data rate may be 31.25Kbps (32us).
  • the symbol needs to be repeated eight times to satisfy the range requirement.
  • the symbol is further reduced to reduce the length of a symbol carrying one piece of information.
  • a symbol using a symbol reduction technique is used to represent one bit, and a specific sequence is applied to every available subcarrier (for example, 13) in m units, and the remaining coefficients are set to zero. do.
  • a 3.2us signal having a 3.2us / m period is generated. Take one of these and map it to the 3.2us / m information signal (information 1).
  • the on signal may be configured as follows.
  • the on signal may be configured as follows.
  • the on signal may be configured as follows.
  • the 3.2us / m information signal is divided into a 3.2us / m on signal and a 3.2us / m off signal.
  • different sequences may be applied to the (usable) subcarriers for the 3.2us / m on signal and the 3.2us / m off signal, respectively.
  • a 3.2us / m off signal can be generated by applying all coefficients to zero.
  • 1 bit information corresponding to a symbol to which a general symbol reduction technique is applied may be represented as shown in the following table.
  • CP + 3.2us / m including CP may indicate one 1-bit information. That is, the 3.2us / m on signal may be viewed as a CP + 3.2us / m on signal, and the 3.2us / m off signal may be viewed as a CP + 3.2us / m off signal.
  • the time used for transmitting one bit (or symbol) except for the guard interval of the transmission signal is 3.2 us.
  • the time used for one bit transmission is 3.2us / m.
  • the time used for transmitting one bit is repeated as 3.2us / m + 3.2us / m by repeating a symbol to which the symbol reduction technique is applied, and the signal between 3.2us / m signals is also used by using the characteristics of Manchester coding. A transition in size was allowed to occur. That is, each sub-information having a length of 3.2us / m should have a value of 0 or 1, and may configure a signal in the following manner.
  • First 3.2us / m signal (sub-information 1 or sub-symbol 1): A specific sequence in m-column for all available subcarriers (e.g. 13 subcarriers) to generate symbols with symbol reduction Apply. That is, in a particular sequence, coefficients may exist at intervals of m columns.
  • the transmitter maps a specific sequence to K consecutive subcarriers of 64 subcarriers and sets a coefficient to 0 for the remaining subcarriers to perform IFFT. In this way, signals in the time domain can be generated. Since the signal in the time domain has coefficients at intervals of m in the frequency domain, a 3.2us signal having a 3.2us / m period is generated. You can take one of these and use it as a 3.2us / m on signal (sub information 1).
  • Second 3.2us / m signal (sub information 0 or subsymbol 0): As with the first 3.2us / m signal, the transmitter maps a particular sequence to K consecutive subcarriers of 64 subcarriers, Can be generated to generate a time domain signal.
  • the sub information 0 may correspond to a 3.2 us / m off signal.
  • the 3.2us / m off signal can be generated by setting all coefficients to zero.
  • One of the first or second 3.2us / m periodic signals of the signal in the time domain may be selected and used as the sub information 0.
  • -Since information 1 is also divided into the first 3.2us / m signal (sub information 0) and the second 3.2us / m signal (sub information 1), the signal corresponding to each sub information is generated in the same way as information 0 is generated. Can be configured.
  • information 0 may be configured as 01 and information 1 may be configured as 10.
  • 1-bit information corresponding to a symbol to which a symbol reduction technique is applied may be represented as shown in the following table.
  • CP is not separately indicated.
  • CP + 3.2us / m including CP may indicate one 1-bit information. That is, the 3.2us / m on signal may be viewed as a CP + 3.2us / m on signal, and the 3.2us / m off signal may be viewed as a CP + 3.2us / m off signal.
  • Embodiments illustrated by option 1 and option 2 of FIG. 12 may be generalized as shown in the following table.
  • Option 1 2,4,8) 2us OFF-signal 2us ON-signal 1us OFF-signal 1us ON-signal 0.5us OFF-signal 0.5us ON-signal
  • Table 11 shows each signal in length including CP. That is, CP + 3.2us / m including the CP may indicate one 1-bit information.
  • a symbol carrying one piece of information becomes CP + 0.8us, and thus a 1us off signal or 1us on signal is composed of a CP (0.2us) + 0.8us signal.
  • a symbol carrying one piece of information becomes CP + 0.4us, and thus a 0.5us off signal or a 0.5us on signal is composed of a CP (0.1us) + 0.4us signal.
  • CP Default symbol (Example 1) (CP + 3.2us) Man. Symbol (Example 2) (CP + 1.6 + CP + 1.6) Man. Symbol (Example 3) (CP + 1.6 + 1.6) 0.4us 277.8 250.0 277.8 0.8us 250.0 208.3 250.0
  • each subband is configured in a 20MHz band when a WUR packet is transmitted to multiple users using 13 subcarriers (subbands) in a situation where there are multiple users of the IEEE 802.11ba system.
  • subbands 13 subcarriers
  • the sequence carried on each subband considers a sequence used for a OOK symbol based Manchester coding or a 1/2 symbol reduction type.
  • 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 consisting of 13 subcarriers in the 20 MHz band can be configured.
  • a wakeup packet of each user may be configured based on a sequence of length 13 as follows.
  • an on-signal may be configured using the following three sequences used for OOK symbol-based Manchester coding or 1/2 symbol reduction type.
  • M1 ⁇ 0,1,0,1,0, -1,0,1,0, -1,0, -1,0 ⁇
  • M2 ⁇ 1,0,1,0,1,0, -1,0, -1,0,1,0, -1 ⁇
  • M3 ⁇ 1,0, -1,0,1,0,0,0, -1,0, -1,0, -1 ⁇
  • the three sequences are optimized sequences in terms of PAPR in a wake-up packet for one user SU.
  • the M3 sequence considers DC and the center coefficient has a value of zero.
  • a WUR packet for a multi-user (MU) using 13 subcarriers is composed of 2 to 4 subbands and can be transmitted to 2 to 4 users.
  • the configuration of each user's subband is as follows.
  • Each number below indicates the number of subcarriers from the front of the number of 20 MHz subcarrier indexes from -32 to 31, the underlined portion indicates the guard tone, and the italics indicates the wakeup packet Means a part and the rest means a null tone.
  • the above definition can be equally applied to the following examples.
  • phase rotation value for each user from the viewpoint of PAPR when an ON-symbol having subbands formed with the M1, M2, and M3 sequences is formed.
  • 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). In addition, we consider the application of four times the IFFT when calculating the PAPR below.
  • two 13 tones (13 subcarriers) can be configured for WUR packets.
  • Each of a means a phase rotation value.
  • Each a may be used in the same sense in the following examples.
  • tone plans such as cases 5 and 7 and in this case the proposed phase rotation values.
  • three 13 tones (13 subcarriers) can be configured for the WUR packet.
  • tone plans such as cases 1 and 4 and in this case the proposed phase rotation values.
  • tone plan such as case 6 and in this case the proposed phase rotation value.
  • two 13 tones (13 subcarriers) can be configured for WUR packets.
  • Each of a means a phase rotation value.
  • Each a may be used in the same sense in the following examples.
  • tone plans such as cases 1, 2, and 4 and in this case the proposed phase rotation values.
  • three 13 tones (13 subcarriers) can be configured for the WUR packet.
  • tone plans such as cases 3, 5, and 6, and in this case the proposed phase rotation values.
  • tone plan such as case 6 and in this case the proposed phase rotation value.
  • tone plans such as cases 4 and 7 and in this case the proposed phase rotation values.
  • two 13 tones (13 subcarriers) can be configured for WUR packets.
  • Each of a means a phase rotation value.
  • Each a may be used in the same sense in the following examples.
  • three 13 tones (13 subcarriers) can be configured for the WUR packet.
  • 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.
  • At least one user may use only some subbands in the 20 MHz band (partial allocation). Even when only some subbands are used, the optimized phase rotation value for each case described above may be used as it is. As an example, considering the case where the second subband is not assigned to a specific user in case 3 in which four subbands are allocated, the above-described optimized phase rotation value may be applied as follows.
  • a parenthesized subband is not assigned to any user, and all subcarriers of this subband may be set to a coefficient of zero.
  • the sequence constituting the remaining subbands may be an M1, M2, or M3 sequence.
  • the following embodiment shows an example in which the above-described optimized phase rotation value is applied when the second subband is not assigned to a specific user in case 3 in which four subbands are allocated.
  • M1 or M2
  • M3 the M3 sequence
  • some users may use the M1 (or M2) sequence and others may use the M3 sequence.
  • the user using the M3 sequence may be a user located in an actual DC.
  • the first subband, the third subband may use an M1 (or M2) sequence, and the second subband may use an M3 sequence as a subband located in DC.
  • Case 1 when three subbands are configured in different sequences is as follows.
  • (a1, a2, a3) (1, j, 1) or (-1, -j, -1) or (j, -1, j) or (-j, 1, -j)
  • FIG. 13 is a flowchart illustrating a procedure of transmitting a wake-up packet through at least one subband according to the present embodiment.
  • FIG. 13 An example of FIG. 13 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.
  • Tones correspond to subcarriers, and hereinafter, tones and subcarriers are used interchangeably.
  • step S1310 the transmitter configures a wake-up packet to which the On-Off Keying (OOK) scheme is applied.
  • OOK On-Off Keying
  • the transmitter transmits the wakeup packet.
  • the wakeup packet includes an on signal and an off signal.
  • the on signal is 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). Coefficients may be inserted in all 13 subcarriers. In addition, coefficients may be inserted in units of two subcarriers in the thirteen subcarriers, and zero may be inserted in the remaining subcarriers.
  • IFFT Inverse Fast Fourier Transform
  • the first sequence may be determined as a predetermined sequence.
  • the first sequence is a 13-bit long sequence and is defined as ⁇ 1,0, -1,0,1,0,0,0, -1,0, -1,0, -1 ⁇ . According to the first sequence, it can be seen that the coefficients are inserted in units of two subcarriers in the 13 subcarriers, so that the on signal may be a 3.2us signal having a period of 1.6us.
  • the wakeup packet is transmitted on at least one subband in the 20MHz band.
  • the subbands should be allocated at least as many as the number of users. For example, to construct a wakeup packet for four users, at least four subbands must be allocated. To construct a wakeup packet for three users, at least three subbands must be allocated. To construct a wakeup packet for two users, at least two subbands must be allocated. In this case, the subband is composed of the 13 subcarriers. In addition, even though a subband is allocated, it may not be used by a specific user, which will be described later.
  • the at least one subband is composed of a sequence in which phase rotation is applied to the first sequence.
  • the first sequence may be determined as a predetermined sequence.
  • the first sequence is a 13-bit long sequence and is defined as ⁇ 1,0, -1,0,1,0,0,0, -1,0, -1,0, -1 ⁇ . Since the coefficient 0 is inserted into the center subcarrier, the first sequence may correspond to the sequence in which the DC subcarrier is considered.
  • a subband for each user may be configured using a sequence considering a DC subcarrier.
  • 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 at least one subband is two, three, or four, it can be described as to which subcarrier (or subband) a wake-up packet is transmitted in 20 MHz as follows.
  • the 20 MHz band may include 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. . That is, the subcarrier indices may be allocated in order from the low subcarrier to the high subcarrier. This applies equally to the case where the number of subbands allocated is different.
  • the first guard subcarrier may include 13 subcarriers
  • the second guard subcarrier may include 12 subcarriers
  • the first null subcarrier may include 13 subcarriers. That is, the manner in which the subcarriers for the wake-up 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].
  • the first subband may be configured as a sequence in which a phase rotation value a1 is applied to the first sequence.
  • the second subband may be configured as a sequence in which a phase rotation value a2 is applied to the first 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, or a1 may be -j and a2 may be j. .
  • 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 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 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 20 MHz band includes a first guard subcarrier, a subcarrier constituting the first subband, a first null subcarrier, a subcarrier constituting the second subband,
  • the second null subcarrier, the subcarrier constituting the third subband, and the second guard subcarrier may be configured in this order.
  • 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. Therefore, 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].
  • the first subband may be configured as a sequence in which a phase rotation value a1 is applied to the first sequence.
  • the second subband may be configured as a sequence in which a phase rotation value a2 is applied to the first sequence.
  • the third subband may be configured of a sequence in which a phase rotation value a3 is applied to the first sequence.
  • A1 is 1, a2 is j, and a3 is 1, a1 is -1, a2 is -j, and a3 is -1, a1 is j, a2 is -1, and a3 may be j, or a1 may be -j, a2 may be 1, and a3 may be -j.
  • 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.
  • 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 and third subbands 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.
  • both coefficients of the subcarrier constituting the first subband and the subcarrier constituting the third subband may be set to zero. . That is, the first and third subbands may not be assigned to any user. In this case, the phase rotation value a2 may be applied to the second subband as it is.
  • both coefficients of the subcarrier constituting the first subband and the subcarrier constituting the second subband may be set to zero. . That is, the first and second subbands 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 20 MHz band includes a first guard subcarrier, a subcarrier constituting the first subband, a first null subcarrier, and a subcarrier constituting the second subband.
  • the first guard subcarrier includes three subcarriers
  • the second guard subcarrier includes two subcarriers
  • the first null subcarrier includes two subcarriers
  • the second null subcarrier may include three subcarriers
  • the third null subcarrier may include two subcarriers. Therefore, a method of arranging subcarriers for wake-up packets in a 20 MHz band when the at least one subband is 4 may be represented as [3 13 2 13 3 13 2 13 2].
  • the first subband may be configured as a sequence in which a phase rotation value a1 is applied to the first sequence.
  • the second subband may be configured as a sequence in which a phase rotation value a2 is applied to the first sequence.
  • the third subband may be configured of a sequence in which a phase rotation value a3 is applied to the first sequence.
  • the fourth subband may be configured of a sequence in which a phase rotation value a4 is applied to the first sequence.
  • A1 is 1, a2 is j, a3 is j, and a4 is 1, a1 is -1, a2 is -j, a3 is -j, and a4 is -1, or a1 May be j, the a2 may be -1, the a3 may be -1, and the a4 may be j, or the a1 may be -j, the a2 may be 1, the a3 may be 1, and the a4 may be -j.
  • a wakeup packet may be transmitted by mapping a user to each of the four 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 is transmitted to four users, the wakeup packet is transmitted to each of the four users on the first subband, the second subband, the third subband, and the fourth subband. Can be. Since four users receive the wakeup packet, all four subbands can be used.
  • the wakeup packet When the wakeup packet is transmitted to three users, the wakeup packet is transmitted through the three subbands of the first subband, the second subband, the third subband, and the fourth subband. May be sent to each of the users. Since there are three users receiving wake-up packets, some of the four subbands (only three) can be used.
  • the wakeup packet When the wakeup packet is transmitted to two users, the wakeup packet is transmitted through two subbands of the first subband, the second subband, the third subband, and the fourth subband. May be sent to each of the users. Since there are two users receiving wake-up packets, some of the four subbands (only two) can be used.
  • the wakeup packet When the wakeup packet is transmitted to one user, the wakeup packet is transmitted through one subband of one of the first subband, the second subband, the third subband, and the fourth subband. May be sent to up to one user. Since only one user receives the wakeup packet, some of the four subbands (only one) can be used.
  • the coefficients of the subcarriers constituting the second subband may be all set to zero. have. That is, the second subband may not be assigned to any user.
  • the phase rotation value a1 is applied to the first subband as it is
  • the phase rotation value a3 is applied to the third subband
  • the phase rotation value a4 is applied to the fourth subband.
  • the off signal may be generated by applying a second sequence to 13 consecutive subcarriers in the 20 MHz band and performing a 64-point IFFT.
  • 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, which is used as a subband of the 20MHz band in the frequency domain.
  • the transmitter may first configure power values of the on signal and the off signal, and configure the on signal and the off signal.
  • the receiver decodes the on signal and the off signal using an envelope detector, thereby reducing power consumed in decoding.
  • FIG. 14 is a block diagram illustrating a wireless device to which the present embodiment can be applied.
  • the wireless device may be an STA or an non-AP STA as an STA capable of implementing the above-described embodiment.
  • the wireless device may correspond to the above-described user or may correspond to a transmission device for transmitting a signal to the user.
  • the wireless device of FIG. 14 includes a processor 1410, a memory 1420, and a transceiver 1430 as shown.
  • the illustrated processor 1410, the memory 1420, and the transceiver 1430 may be implemented as separate chips, or at least two blocks / functions may be implemented through one chip.
  • the transceiver 1430 is a device including a transmitter and a receiver. When a specific operation is performed, only one of the transmitter and the receiver may be performed, or both the transmitter and the receiver may be performed. Can be.
  • the transceiver 1430 may include one or more antennas for transmitting and / or receiving wireless signals.
  • the transceiver 1430 may include an amplifier for amplifying a reception signal and / or a transmission signal and a bandpass filter for transmission on a specific frequency band.
  • the processor 1410 may implement the functions, processes, and / or methods proposed herein.
  • the processor 1410 may perform an operation according to the above-described embodiment. That is, the processor 1410 may perform the operations disclosed in the embodiments of FIGS. 1 to 13.
  • the processor 1410 may include an application-specific integrated circuit (ASIC), another chipset, a logic circuit, a data processing device, and / or a converter for translating baseband signals and wireless signals.
  • the memory 1420 may include read-only memory (ROM), random access memory (RAM), flash memory, memory card, storage medium, and / or other storage device.
  • FIG. 15 is a block diagram illustrating an example of an apparatus included in a processor. For convenience of description, an example of FIG. 15 is described based on a block for a transmission signal, but it is obvious that the reception signal can be processed using the block.
  • the illustrated data processor 1510 generates transmission data (control data and / or user data) corresponding to the transmission signal.
  • the output of the data processor 1510 may be input to the encoder 1520.
  • the encoder 1520 may perform coding through a binary convolutional code (BCC) or a low-density parity-check (LDPC) technique. At least one encoder 1520 may be included, and the number of encoders 1520 may be determined according to various information (eg, the number of data streams).
  • BCC binary convolutional code
  • LDPC low-density parity-check
  • the output of the encoder 1520 may be input to the interleaver 1530.
  • the interleaver 1530 distributes a continuous bit signal over radio resources (eg, time and / or frequency) to prevent burst errors due to fading or the like.
  • Radio resources eg, time and / or frequency
  • At least one interleaver 1530 may be included, and the number of the interleaver 1530 may be determined according to various information (for example, the number of spatial streams).
  • the output of the interleaver 1530 may be input to a constellation mapper 1540.
  • the constellation mapper 1540 performs constellation mapping such as biphase shift keying (BPSK), quadrature phase shift keying (QPSK), quadrature amplitude modulation (n-QAM), and the like.
  • the output of the constellation mapper 1540 may be input to the spatial stream encoder 1550.
  • the spatial stream encoder 1550 performs data processing to transmit the transmitted signal through at least one spatial stream.
  • the spatial stream encoder 1550 may perform at least one of space-time block coding (STBC), cyclic shift diversity (CSD) insertion, and spatial mapping on a transmission signal.
  • STBC space-time block coding
  • CSS cyclic shift diversity
  • the output of the spatial stream encoder 1550 may be input to an IDFT 1560 block.
  • the IDFT 1560 block performs an inverse discrete Fourier transform (IDFT) or an inverse Fast Fourier transform (IFFT).
  • IDFT inverse discrete Fourier transform
  • IFFT inverse Fast Fourier transform
  • the output of the IDFT 1560 block is input to the Guard Interval (GI) inserter 1570, and the output of the GI inserter 1570 is input to the transceiver 1430 of FIG. 14.
  • GI Guard Interval

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Abstract

L'invention concerne un procédé et un appareil de transmission d'une trame de réveil dans un système de LAN sans fil. Plus particulièrement, un appareil de transmission configure une trame de réveil à laquelle un schéma OOK est appliqué, et transmet la trame de réveil à un appareil de réception. La trame de réveil est constituée d'un signal de marche et d'un signal d'arrêt. Le signal de marche est généré par l'application d'une première séquence à 13 sous-porteuses consécutives dans la bande de 20 MHz et en réalisant une IFFT à 64 points. Le paquet de réveil est transmis par l'intermédiaire d'au moins une sous-bande dans la bande de 20 MHz. Ladite sous-bande est constituée d'une séquence dans laquelle la rotation de phase est appliquée à la première séquence. La première séquence est une séquence de 13 bits de longueur et est définie comme étant {1, 0, -1, 0, 1, 0, 0, 0, -1, 0, -1, 0, -1}.
PCT/KR2018/001482 2017-03-02 2018-02-05 Procédé et appareil de transmission de paquet de réveil dans un système lan sans fil WO2018159945A1 (fr)

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