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WO2019146969A1 - Procédé et appareil de transmission de paquet de réveil dans un système de réseau local sans fil - Google Patents

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

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Publication number
WO2019146969A1
WO2019146969A1 PCT/KR2019/000813 KR2019000813W WO2019146969A1 WO 2019146969 A1 WO2019146969 A1 WO 2019146969A1 KR 2019000813 W KR2019000813 W KR 2019000813W WO 2019146969 A1 WO2019146969 A1 WO 2019146969A1
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Prior art keywords
signal
sequence
subcarriers
information
symbol
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English (en)
Korean (ko)
Inventor
박은성
김진민
윤선웅
임동국
천진영
최진수
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LG Electronics Inc
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LG Electronics Inc
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • 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
    • 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 invention relates to a technique for performing low-power communication in a wireless LAN system, and more particularly, to a method and apparatus for transmitting a wakeup packet by applying an OOK scheme in a wireless LAN system.
  • next generation wireless local area network Discussions are under way for the next generation wireless local area network (WLAN).
  • next generation WLAN 1) enhancement of IEEE 802.11 PHY (physical) layer and MAC (medium access control) layer in the 2.4GHz and 5GHz bands, 2) improvement of spectrum efficiency and area throughput throughput, and 3) to improve performance in real indoor and outdoor environments, such as environments where interference sources exist, dense heterogeneous networks, and environments with high user loads.
  • next generation WLAN The environment that is considered mainly in the next generation WLAN is a dense environment with AP (access point) and STA (station), and improvement in spectrum efficiency and area throughput is discussed in this dense environment.
  • next generation WLAN is concerned not only with the indoor environment but also with the actual performance improvement in the outdoor environment which is not considered much in the existing WLAN.
  • next-generation WLAN is interested in scenarios such as wireless office, smart home, stadium, hotspot, and building / apartment, And STA in a dense environment.
  • next generation WLAN improvement of system performance in an overlapping basic service set (OBSS) environment, improvement of outdoor environment performance, and cellular offloading will be actively discussed rather than improvement of single link performance in one basic service set (BSS) It is expected.
  • OBSS overlapping basic service set
  • BSS basic service set
  • the directionality of this next generation WLAN means that the next generation WLAN will have a technology range similar to that of mobile communication. Considering the recent discussions of mobile communication and WLAN technology in the area of small cell and D2D (direct-to-direct) communication, it is expected that the technological and business convergence of next generation WLAN and mobile communication will become more active.
  • the present invention proposes a method and apparatus for transmitting a wakeup packet by applying the OOK scheme in a wireless LAN system.
  • One example of the present disclosure proposes a method and apparatus for transmitting a wakeup packet to a WLAN system.
  • the present embodiment can be operated in the transmitting apparatus, the receiving apparatus can correspond to the low power wake up receiver, and the transmitting apparatus can correspond to the AP.
  • the on signal can correspond to a signal having an actual power value.
  • An off signal may correspond to a signal that does not have an actual power value.
  • the transmitting apparatus constructs a wakeup packet by applying an on-off keying (OOK) scheme.
  • OOK on-off keying
  • the transmitting apparatus transmits the wakeup packet to the receiving apparatus.
  • the configuration of the wakeup packet in this embodiment is as follows.
  • the wakeup packet includes an ON signal and an OFF signal.
  • the on-signal is generated by inserting a first sequence into 13 consecutive subcarriers in the 20 MHz band and performing 64-point IFFT (Inverse Fast Fourier Transform).
  • the concrete procedure of generating the on-signal is as follows.
  • the number of coefficients of the first sequence is seven.
  • the coefficients of the first sequence are inserted into each of the 13 subcarriers for every 2 subcarriers. Since the number of coefficients of the first sequence is not 13, it can not be inserted one-to-one into thirteen subcarriers. Therefore, assuming that the index (1 to 13) of 13 coefficients is assigned to the coefficient (7) of the first sequence, a subcarrier having an index of 1, 3, 5, 7, 9, 11, As shown in FIG.
  • 0 can be inserted in a subcarrier in which coefficients of the first sequence are not inserted. That is, 0 can be inserted into subcarriers having indexes of 2, 4, 6, 8, 10, and 12 among the 13 subcarriers.
  • the DC subcarrier (middle subcarrier) can be set to zero.
  • the on-signal may be generated by inserting a CP (Cyclic Prefix) after masking half of the generated signal by inserting the first sequence into the 13 subcarriers and performing 64-point IFFT.
  • the signal generated by performing the 64-point IFFT may be a 3.2 us signal having a period of 1.6 us. If the first or last 1.6 us signal among the 3.2 us signals having a period of 1.6 us is selected (half is masked) and a 0.4us CP is inserted, an on signal of 2us can be generated.
  • the data rate of the wakeup packet is 250 Kbps
  • the length of the ON signal is 2 us
  • the length of the CP may be 0.4 us.
  • the coefficients of the first sequence are set to one of values indicated by a constellation point of 16 QAM (Quadrature Amplitude Modulation).
  • the 16 QAM may be a modulation scheme used in an 802.11ac system.
  • the value indicated by the constellation point of the 16 QAM is 1 + j, -1 + j, -1-j, 1-j, 3 + j, -3 + j, 3j, -1 + 3j, -1-3j, 1-3j, 3 + 3j, -3 + 3j, -3-3j and 3-3j.
  • the sequence for minimizing PAPR is as follows.
  • the first sequence may be set to a second sequence, and the second sequence may be [1 + j, 3 + j, 3-j, 0, -1 + 3j, -1-3j, 1 + j].
  • the Peak-to-Average Power Ratio (PAPR) of the second sequence may be 0.7239 dB. That is, the PAPR can be minimized when using the second sequence.
  • the first sequence may be set to a sequence obtained by multiplying the second sequence by -1, j, or -j and applying phase rotation. Even if a phase rotation is applied, it may have the same PAPR as that used in the second sequence.
  • the power normalization value of the first sequence may be 1 / sqrt (44).
  • the power normalization value may be a value such that the average power of the first sequence is unity. That is, instead of considering the total constellation point of 16 QAM, only 1 / sqrt (44) may be multiplied so that the average energy of the first sequence becomes 1 considering only the first sequence having a length of 7.
  • the number of coefficients of the first sequence may be 13. At this time, the coefficients of the first sequence may be inserted one-to-one among the 13 subcarriers. However, the DC subcarrier (middle subcarrier) can be set to zero.
  • the on-signal may be generated by inserting the first sequence (length 13) into the 13 subcarriers and inserting a CP into the generated signal by performing 64-point IFFT.
  • the signal generated by performing the 64-point IFFT is 3.2us signal, and when the CP of 0.8us is inserted, the on-signal of 4us can be generated.
  • the data rate of the wakeup packet is 62.5 Kbps
  • the length of the ON signal is 4us
  • the length of the CP may be 0.8us.
  • the coefficient of the first sequence can be set to a value indicated by constellation points of BPSK, QPSK, 16QAM, and 256QAM in the 802.11ac system.
  • Each modulation scheme is set as a coefficient of a sequence used in the 802.11 ba system has been described above.
  • the coefficients of the first sequence may be set to one of the values indicated by the constellation point of QPSK.
  • the first sequence that minimizes the PAPR is [1 + j, -1-j, 1 + j, 1 + j, -1-j, 1 + j, 0, 1 + j, -1-j, -1-j, -1-j].
  • the transmitting apparatus can configure the ON signal and the OFF signal to know the power value of the ON signal and the OFF signal first.
  • the receiving apparatus decodes the ON signal and the OFF signal using an envelope detector, thereby reducing power consumed in decoding.
  • a transmission apparatus constructs and transmits a wakeup packet by applying an OOK modulation scheme, so that power consumption can be reduced by using an envelope detector in a wakeup decoding at a receiving apparatus. Therefore, the receiving apparatus can decode the wakeup packet with the minimum power.
  • the PAPR can be minimized by setting a sequence for generating the on-signal based on the constellation point of the modulation scheme used in the 802.11ac system.
  • WLAN wireless local area network
  • FIG. 2 is a diagram showing an example of a PPDU used in the IEEE standard.
  • FIG. 3 is a diagram showing an example of an HE PPDU.
  • Figure 4 is a diagram illustrating a low power wake up receiver in an environment where no data is received.
  • FIG. 5 is a diagram illustrating 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 the wakeup packet according to the present embodiment.
  • FIG. 8 is a diagram for explaining a principle in which power consumption is determined according to a ratio of 1 and 0 of a bit value constituting binary sequence type information using the OOK scheme.
  • FIG. 10 is an explanatory diagram of a Manchester coding technique according to the present embodiment.
  • FIG. 11 shows various examples of a symbol repetition technique in which n symbols according to the present embodiment are repeated.
  • FIG. 13 shows an example of configuring the 2us on signal based on signal masking according to the present embodiment.
  • FIG 14 shows an example of a wakeup packet structure to which different sync parts are applied according to the present embodiment.
  • 15 shows a constellation diagram of BPSK modulation.
  • 16 shows a constellation diagram of QPSK modulation.
  • 17 shows a constellation diagram of 16QAM modulation.
  • 19 to 22 show constellations of 256QAM modulation.
  • FIG. 23 is a flowchart illustrating a procedure for transmitting a wakeup packet by applying the OOK scheme according to the present embodiment.
  • FIG. 25 shows a procedure for transmitting a WUR PPDU configured by applying an OOK scheme between an AP and a WUR STA according to the present embodiment.
  • 26 shows a receiving apparatus for implementing this embodiment.
  • WLAN wireless local area network
  • FIG. 1 shows the structure of an infrastructure basic service set (BSS) of Institute of Electrical and Electronic Engineers (IEEE) 802.11.
  • 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 an STA1 (station 100-1) capable of successfully synchronizing and communicating with each other.
  • the BSS 105 may include one or more associatable STAs 105-1 and 105-2 in one AP 130.
  • the BSS may include at least one STA, APs 125 and 130 providing a distribution service, and a distribution system (DS) 110 connecting a plurality of APs.
  • DS distribution system
  • the distributed system 110 may implement an extended service set (ESS) 140 that is an extended service set by connecting a plurality of BSSs 100 and 105.
  • ESS 140 may be used to refer to one network in which one or more APs 125 and 230 are connected through a distributed system 110.
  • An AP included in one ESS 140 may have the same service set identification (SSID).
  • a portal 120 may serve as a bridge for performing a connection between a wireless LAN network (IEEE 802.11) and another network (for example, 802.X).
  • IEEE 802.11 IEEE 802.11
  • 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 in the BSS as shown in the upper part of FIG. However, it is also possible to establish a network and perform communication between the STAs without the APs 125 and 130.
  • An ad-hoc network or an independent basic service set (IBSS) is defined as a network that establishes a network and establishes communication between STAs without APs 125 and 130.
  • 1 is a conceptual diagram showing IBSS.
  • the IBSS is a BSS operating in an ad-hoc mode. Since IBSS does not include APs, 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 the STAs 150-1, 150-2, 150-3, 155-4, and 155-5 may be mobile STAs, and the access to the distributed system is not allowed, network.
  • the STA is an arbitrary functional medium including a medium access control (MAC) conforming to IEEE (Institute of Electrical and Electronics Engineers) IEEE 802.11 standard and a physical layer interface for a wireless medium. May be used to mean both an AP and a non-AP STA (Non-AP Station).
  • MAC medium access control
  • IEEE 802.11 Institute of Electrical and Electronics Engineers
  • the STA may be a mobile terminal, a wireless device, a wireless transmit / receive unit (WTRU), a user equipment (UE), a mobile station (MS), a mobile subscriber unit Mobile Subscriber Unit), or simply a user.
  • WTRU wireless transmit / receive unit
  • UE user equipment
  • MS mobile station
  • Mobile Subscriber Unit Mobile Subscriber Unit
  • the term 'user' may be used in various meanings.
  • the term 'user' may be used to mean an STA participating in uplink MU MIMO and / or uplink OFDMA transmission in wireless LAN communication, But is not limited thereto.
  • FIG. 2 is a diagram showing an example of a PPDU used in the IEEE standard.
  • PPDU PHY protocol data unit
  • LTF and STF fields included training signals
  • SIG-A and SIG-B included control information for the receiving station
  • the data field 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 can be applied on the HE PPDU (high efficiency PPDU) according to the IEEE 802.11ax standard. That is, the signal to be improved in this 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 can also be expressed as SIG-A, SIG-B.
  • the improved signal proposed by the present embodiment is not necessarily limited to the HE-SIG-A and / or HE-SIG-B standards, and various control and control schemes including control information in a wireless communication system, It is applicable to data fields.
  • FIG. 3 is a diagram showing an example of an HE PPDU.
  • the control information field proposed in this embodiment may be HE-SIG-B included in the HE PPDU as shown in FIG.
  • the HE PPDU according to FIG. 3 is an example of a PPDU for multiple users.
  • the HE-SIG-B is included only for multi-user, and the corresponding HE-SIG-B can be omitted for a PPDU for a single user.
  • an HE-PPDU for a Multiple User includes a legacy-short training field (L-STF), a legacy-long training field (L-LTF) (HE-SIG-A, HE-SIG-B, HE-STF, HE-LTF) , A data field (or MAC payload), and a Packet Extension (PE) field.
  • L-STF legacy-short training field
  • L-LTF legacy-long training field
  • PE Packet Extension
  • the PPDU used in the IEEE standard is mainly described by a PPDU structure transmitted over a channel bandwidth of 20 MHz.
  • the PPDU structure transmitted over a wide bandwidth (for example, 40 MHz, 80 MHz) than the channel bandwidth of 20 MHz may be a structure applying linear scaling to the PPDU structure used in the channel bandwidth of 20 MHz.
  • the PPDU structure used in the IEEE standard is generated based on 64 FFT (Fast Fourier Transform), and the CP portion (cyclic prefix portion) can be 1/4.
  • the length of the effective symbol interval (or the FFT interval) is 3.2us
  • the length of the CP 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 and are usually installed indoors and often outdoors. Wireless networks transmit and receive information using a variety of technologies.
  • the two widely deployed technologies used in communications are those that comply with the IEEE 802.11 standard, 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 various functions to support the operation of an IEEE 802.11-based wireless LAN (WLAN).
  • the MAC layer utilizes a protocol that coordinates access to the shared radio and improves communication over the wireless medium to enable the wireless network card (NIC) or other wireless device or station (STA) and access point AP)).
  • NIC wireless network card
  • STA wireless device or station
  • AP access point AP
  • IEEE 802.11ax is a follow-on product of 802.11ac and has been proposed to increase the efficiency of WLAN networks, especially in high density areas such as public hotspots and other high density traffic areas.
  • IEEE 802.11 may also use orthogonal frequency division multiple access (OFDMA).
  • OFDMA orthogonal frequency division multiple access
  • the High Efficiency WLAN Study Group (HEW SG) within the IEEE 802.11 Work Group has been developing a spectrum for improving the system throughput / area in high density scenarios of AP (Access Point) and / or STA (Station) Efficiency is being considered.
  • Small computing devices such as wearable devices and sensors and mobile devices are limited by small battery capacities, but are not limited to wireless communication technologies such as Wi-Fi, Bluetooth®, and Bluetooth® Low Energy (BLE) Support, and connect to and exchange data with other computing devices such as smart phones, tablets, and computers. Since such communication consumes power, it is important to minimize the energy consumption of such communication in such devices.
  • One ideal strategy for minimizing energy consumption is to turn off the power to the communication block as often as possible while maintaining data transmission and reception without increasing the delay too much. That is, the communication block is transmitted immediately before data reception, and the communication block is turned on only when there is data to be woken up, and the communication block is turned off for the remaining time.
  • LP-WUR low-power wake-up receiver
  • the communication system (or communication subsystem) described herein includes a main radio (802.11) and a low power wake up receiver.
  • the main radio is used for transmitting and receiving user data.
  • the main radio turns off if there is no data or packet to transmit.
  • a low-power wake-up receiver wakes up the main radio when there are packets to receive. At this time, the user data is transmitted and received by the main radio.
  • a low power wakeup receiver is not for user data. It is simply a receiver for waking up the main radio. That is, the transmitter is not included.
  • a low-power wake-up receiver is active while the main radio is off.
  • a low-power wake-up receiver targets a target power consumption of less than 1mW in the active state.
  • a low power wake up receiver also uses a narrow bandwidth of less than 5 MHz.
  • the target transmission range of the low power wakeup receiver is the same as the target transmission range of the existing 802.11.
  • Figure 4 is a diagram illustrating a low power wake up receiver in an environment where no data is received.
  • 5 is a diagram illustrating a low power wake up receiver in an environment in which data is received;
  • one way to implement an ideal transmission / reception strategy is to use a main radio such as Wi-Fi, Bluetooth® radio, Bluetooth® Radio (BLE) Wake up receiver (LP-WUR) that can wake up the system.
  • a main radio such as Wi-Fi, Bluetooth® radio, Bluetooth® Radio (BLE) Wake up receiver (LP-WUR) that can wake up the system.
  • the Wi-Fi / BT / BLE 420 is off and the low power wakeup receiver 430 is turned on with no data received.
  • Some studies show that the power consumption of these low-power wake-up receivers (LP-WUR) can be less than 1mW.
  • the low power wakeup receiver 530 when a wakeup packet is received, the low power wakeup receiver 530 sends a full Wi-Fi / BT / BLE radio 520 ). 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 should be woken up to perform the required process. This can result in significant power savings.
  • One exemplary technique disclosed herein defines a method for a granular wake-up mode for Wi-Fi / BT / BLE using a low power wake-up receiver. For example, the actual data contained in the wakeup packet can be passed directly to the device's memory block without waking the Wi-Fi / BT / BLE radio.
  • the PHY module of the Wi-Fi / BT / BLE radio can be turned off or kept in a low power mode.
  • a number of fine-grained wake-up modes are defined for Wi-Fi / BT / BLE radios using low-power wake-up receivers to power on the Wi-Fi / BT / BLE radio when a wakeup packet is received.
  • only necessary parts (or components) of the Wi-Fi / BT / BLE radio are selectively awakened, saving energy and reducing standby time.
  • Many solutions that use a low-power wake-up receiver to wake up a wake-up packet wake up the entire Wi-Fi / BT / BLE radio.
  • One exemplary aspect discussed herein is to wake up only the necessary portion of the Wi-Fi / BT / BLE radio needed to process the received data, thereby saving a significant amount of energy and reducing unnecessary latency in waking up the main radio .
  • the low power wakeup receiver 530 may wake up the main radio 520 based on the wakeup packet transmitted from the transmitting apparatus 500.
  • the transmitting apparatus 500 can be set to transmit a wakeup packet to the receiving apparatus 510.
  • the main radio 520 may instruct the low power wake up receiver 530 to wake up.
  • 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 also include a payload after the legacy preamble.
  • the payload may be modulated by a simple modulation scheme, e.g., an On-Off Keying (OOK) modulation scheme.
  • OOK On-Off Keying
  • a transmitting device 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 defined by the IEEE 802.11 specification or any other preamble 610.
  • the wakeup packet 600 may include a payload 620.
  • the legacy preamble provides coexistence with the legacy STA.
  • the legacy preamble 610 for coexistence uses the L-SIG field to protect the packet.
  • the 802.11 STA can detect the beginning of a packet.
  • the 802.11 STA can know the end of the packet.
  • One symbol modulated with BPSK also has a bandwidth of 20MHz like a legacy part.
  • the legacy preamble 610 is a field for a third party legacy STA (STA not including the LP-WUR).
  • the legacy preamble 610 is not decoded from the LP-WUR.
  • the payload 620 may include a wakeup preamble 622.
  • the wake-up preamble 622 may comprise a sequence of bits configured to identify the wake-up packet 600.
  • the wakeup preamble 622 may include, for example, a PN sequence.
  • the payload 620 may also include a MAC header 624 that includes the address information of the receiving device that receives the wakeup packet 600 or the identifier of the receiving device.
  • the payload 620 may include a frame body 626 that may contain other information of the wakeup packet.
  • frame body 626 may include payload length or size information.
  • 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
  • the MAC header 624 and the CRC-8 value or CRC-16 value of the frame body 626 may include a Frame Check Sequence (FCS) field 628 that includes a Cyclic Redundancy Check (CRC) value.
  • CRC Cyclic Redundancy Check
  • FIG. 7 shows a signal waveform of the wakeup packet according to this embodiment.
  • the wakeup packet 700 includes a legacy preamble (802.11 preamble, 710) and a payload modulated with OOK. That is, the legacy preamble and the new LP-WUR signal waveform coexist.
  • the legacy preamble 710 can be modulated according to the OFDM modulation scheme. That is, the legacy preamble 710 does not use the OOK scheme.
  • the payload can be modulated according to the OOK scheme.
  • the payload wakeup preamble 722 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 in the OOK pulse design method described later.
  • FIG. 8 is a diagram for explaining a principle in which power consumption is determined according to a ratio of 1 and 0 of a bit value constituting binary sequence type information using the OOK scheme.
  • a binary sequence type information having 1 or 0 as a bit value is represented.
  • the bit value of 1 or 0 of the information of the binary sequence type it is possible to perform communication in the OOK modulation method. That is, the communication of the OOK modulation method can be performed in consideration of the bit values of the binary sequence type information. For example, when the light emitting diode is used for visible light communication, the light emitting diode is turned on when the bit value constituting the binary sequence information is 1, and the light emitting diode is turned off when the bit value is 0 The light emitting diode can be made to blink.
  • the light emitting diode As the light emitting diode is turned on and off, the data received in the form of visible light is received and restored by the receiving device, thereby enabling communication using visible light.
  • the human eye can not recognize the blinking of such a light emitting diode, the person feels that the illumination is continuously maintained.
  • FIG. 8 For convenience of description, information of a binary sequence type having 10 bit values is used as shown in FIG. Referring to FIG. 8, there is binary sequence type information having a value of '1001101011'.
  • the bit value when the bit value is 1, the transmitting apparatus is turned on.
  • the bit value when the transmitting apparatus is turned off, 6 bits of the 10 bit values are turned on. ) do. Therefore, assuming that all the 10 bit values have a power consumption of 100% when a symbol is turned on, it can be said that the power consumption is 60% in accordance with the duty cycle of FIG. 8.
  • the power consumption of the transmitter is determined by the ratio of 1 and 0 composing binary sequence type information.
  • the ratio of 1 to 0 constituting binary sequence information should also be maintained.
  • the ratio of 1 and 0 constituting binary sequence information should also be maintained.
  • the receiving apparatus is the main body of the wake-up receiver (WUR)
  • the transmission power is not important.
  • the main reason for using OOK is that the power consumption in decoding the received signal is very low. There is no significant difference in power consumption in the main radio or WUR until decoding, but there is a big difference 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) can occur.
  • WUR power consumption is about 1mW.
  • power consumption of Resonator + Oscillator (600uW) -> LPF (300uW) -> ADC (20uW) -> decoding processing (Envelope detector) (1uW) can occur.
  • the OFDM transmitter of 802.11 can be reused to generate OOK pulses.
  • the transmitting apparatus can generate a sequence having 64 bits by applying a 64-point IFFT like the existing 802.11.
  • the transmitting apparatus must generate the payload of the wakeup packet by modulating it in the OOK manner.
  • 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.
  • Off signal is also applied to the OOK scheme, but the signal is not generated using the transmitting apparatus, but is not considered in the configuration of the wakeup packet because there is no signal actually transmitted.
  • information (bit) 1 is an ON signal and information (bit) 0 can be an OFF signal.
  • applying the Manchester coding scheme may indicate that information 1 transitions from an off signal to an on signal, and information 0 may be transited from an on signal to an off signal.
  • information 1 indicates that transition from the on-signal to the off-signal
  • information 0 indicates that the transition from the off-signal to the on-signal.
  • the Manchester coding scheme will be described later.
  • the transmitter applies a sequence by selecting 13 consecutive subcarriers in the 20 MHz band, which is a reference band, as a sample.
  • 13 subcarriers located in the middle of the 20 MHz band subcarriers are selected as samples. That is, subcarriers whose subcarrier indices are from -6 to +6 out of 64 subcarriers are selected.
  • the subcarrier index 0 can be nulled to 0 on the DC subcarrier.
  • a specific sequence is set only for thirteen subcarriers selected as samples, and the remaining subcarriers excluding subcarriers (subcarrier indices -32 to -7 and subcarrier indices +7 to +31) are all set to 0 .
  • the subcarrier spacing is 312.5 KHz
  • 13 subcarriers have a channel bandwidth of about 4.06 MHz. That is, it can be seen that there is power only for 4.06 MHz in the 20 MHz band in the frequency domain.
  • the signal to noise ratio (SNR) can be increased and the power consumption of the AC / DC converter of the receiving apparatus can be reduced.
  • the sampling frequency band is reduced to 4.06 MHz, power consumption can be reduced.
  • the transmitter can perform one 64-point IFFT on 13 subcarriers to generate one ON signal in the time domain.
  • One ON signal has a size of 1 bit. That is, a sequence composed of 13 subcarriers can correspond to one bit.
  • the transmitting apparatus may not transmit the OFF signal at all. If IFFT is performed, a symbol of 3.2 us can be generated, and if a CP (Cyclic Prefix, 0.8 us) is included, a symbol having a length of 4 us can be generated. That is, one bit indicating one on-signal can be stored in one symbol.
  • CP Cyclic Prefix, 0.8 us
  • the reason why the bits are constructed and transmitted as in the above-described embodiment is to reduce the power consumption by using an envelope detector in the receiving apparatus. Thereby, the receiving apparatus can decode the packet with the minimum power.
  • the basic data rate for one piece of information may be 125 Kbps (8 us) or 62.5 Kbps (16 us).
  • each signal having a length K in the 20 MHz band can be transmitted on K consecutive subcarriers out of a total of 64 subcarriers. That is, K can correspond to the bandwidth of the OOK pulse by the number of subcarriers used for transmitting the signal.
  • the coefficients of subcarriers other than K are all zero.
  • the indexes of the K subcarriers used by the signals corresponding to information 0 and information 1 are the same.
  • the subcarrier index used may be expressed as 33-floor (K / 2): 33 + ceil (K / 2) -1.
  • information 1 and information 0 may have the following values.
  • Alpha is a power normalization factor and may be, for example, 1 / sqrt (K).
  • FIG. 10 is an explanatory diagram of a Manchester coding technique according to the present embodiment.
  • Manchester coding is a kind of line coding, and it can represent information as shown in the following table in such a manner that a transition of a magnitude value takes place in the middle of one bit period.
  • the Manchester coding scheme refers to a method of converting data with 1 as 01, 0 as 10, or 1 as 10 and 0 as 01.
  • Table 1 shows an example in which Manchester coding is used and data is converted to 1 by 10 and 0 by 01.
  • bit stream to be transmitted As shown in Fig. 10, the bit stream 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 receiving side When data is transmitted from the transmitting side using the Manchester coding scheme, the receiving side reads data slightly after the transition point transition from 1? 0 or 0? 1 to recover data, and transitions from 1? 0 or 0? 1 And the clock is restored by recognizing the transition advantage of the clock as a transition point of the clock.
  • the symbol when the symbol is divided based on the transition point, it can be simply decoded by comparing the power of the front part and the rear part at the center of the symbol.
  • the bit string to be transmitted is 10011101
  • the Manchester coded bit stream to be transmitted is 0110100101011001
  • the clock reproduced at the receiving side recognizes the transition point of the Manchester coded signal as the transition point of the clock And recover data using the recovered clock.
  • a synchronous communication can be performed using only a data transmission channel without using a separate clock.
  • such a scheme can use the TXD pin for data transmission, and the RXD pin for data transmission by using only the data transmission channel. Therefore, synchronized bidirectional transmission is possible.
  • the present specification proposes various symbol types that can be used in WUR and the corresponding data rates.
  • each symbol can be generated using existing 802.11 OFDM transmission.
  • the number of subcarriers used for generating each symbol may be 13. However, it is not limited thereto.
  • each symbol can use OOK modulation, which is formed by 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 portion indicating actual information. It is possible to design a symbol having various data rates by repeatedly setting or repeating the CP and the length of the actual information signal.
  • CP Cyclic Prefix or Guard Interval
  • the basic WUR symbol can be represented as CP + 3.2us. That is, 1 bit is represented using a symbol having the same length as the existing Wi-Fi.
  • the transmitter applies a specific sequence to all available subcarriers (e.g., 13 subcarriers) and then performs an IFFT to form an information signal portion of 3.2 us.
  • a coefficient of 0 may be stored in the DC subcarrier or the middle subcarrier index among all available subcarriers.
  • the 3.2 off signal can be generated by applying all coefficients to zero.
  • the CP can be used by adopting a specific length behind the information signal 3.2us immediately behind it. At this time, CP may be 0.4us or 0.8us. This length is the same as the guard interval of the 802.11ac.
  • 1-bit information corresponding to one basic WUR symbol can be represented as shown in the following table.
  • CP is not indicated separately.
  • CP + 3.2us including CP, can point to a single bit of information. That is, the 3.2us on signal can be seen as (CP + 3.2us) on signal.
  • 3.2 us off signal can be seen as (CP + 3.2us) off signal.
  • the Manchester coded symbols can be represented as CP + 1.6us + CP + 1.6us or CP + 1.6us + 1.6us.
  • the Manchester coded symbols can be generated as follows.
  • the time used for transmission of one bit (or symbol) excluding the guard interval of the transmission signal is 3.2us.
  • the signal size should be shifted at 1.6us. That is, each sub-information having a length of 1.6us must have a value of 0 or 1, and a signal can be configured in the following manner.
  • Sub information 1 can have the value of beta * ones (1, K).
  • the beta is a power normalizing factor and may be, for example, 1 / sqrt (ceil (K / 2)).
  • a specific sequence is applied to all available subcarriers (e.g., 13 subcarriers) in units of two to generate Manchester coded symbols. That is, even-numbered subcarriers in a specific sequence are null-nulled. That is, a particular sequence may have coefficients at intervals of two squares.
  • a specific sequence with coefficients in two spaces 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 0 d 0 e 0 f ⁇ .
  • a, b, c, d, e, f, and g are 1 or -1.
  • the transmitting apparatus maps a specific sequence to consecutive K subcarriers among 64 subcarriers (for example, 33-floor (K / 2): 33 + ceil (K / 2) And sets the coefficient to 0 to perform IFFT.
  • a signal in the time domain can be generated.
  • the signal in the time domain is a signal having a length of 3.2us having a period of 1.6us because the coefficient exists at intervals of two spaces in the frequency domain.
  • the first or second 1.6us period signal can be selected and used as sub information 1.
  • sub information 0 can have the value of zeros (1, K).
  • the transmitting apparatus maps a specific sequence to consecutive K subcarriers among 64 subcarriers (for example, 33-floor (K / 2): 33 + ceil (K / 2) -1) IFFT So that a signal in the time domain can be generated.
  • Sub information 0 can correspond to 1.6us off signal.
  • the 1.6us off signal can be generated by setting all coefficients to zero.
  • One of the first or second 1.6 us periodic signals of the time domain signal may be selected and used as the sub information 0.
  • the zeros (1, 32) signal can be simply used as sub information 0.
  • - Information 1 is divided into the first 1.6 us (sub information 0) and the second 1.6 us (sub information 1), so that a signal corresponding to each sub information can be configured in the same manner as the method of generating information 0.
  • the coexistence problem is a problem that occurs when another device determines a channel idle state due to consecutive off-symbols and transmits a signal. If only OOK modulation is used, for example, the off-symbol may be continuous with a sequence of 100001 or the like, but when Manchester coding is used, the off-symbol can not be continuous with the sequence of 100101010110.
  • the sub information may be called 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 can be applied to different subcarriers.
  • CP can be used by adopting a specific length behind the information signal 1.6us immediately behind it. At this time, CP may be 0.4us or 0.8us. This length is the same as the guard interval of the 802.11ac.
  • 1-bit information corresponding to a symbol to which one Manchester coding is applied can be represented as shown in the following table.
  • CP is not indicated separately.
  • CP + 1.6us + CP + 1.6us or CP + 1.6us + 1.6us, including CP can point to a single bit of information. That is, in the case of the former, the signal is 1.6us on, the signal 1.6us off is (CP + 1.6us) on, and (CP + 1.6us) is off.
  • a method of constructing a wakeup packet by repeating symbols is proposed to improve performance.
  • the symbol repetition scheme is applied to the wakeup payload 724.
  • the symbol repetition scheme means repetition of time signals after insertion of IFFT and CP (Cyclic Prefix) of each symbol.
  • IFFT and CP Cyclic Prefix
  • Option 1 Information 0 and information 1 can be repeated with the same symbol.
  • Option 2 Information 0 and information 1 can be repeated with different symbols.
  • the transmitted signal can correspond to the wakeup packet, and the method for decoding the wakeup packet can be largely divided into two methods.
  • the first is the non-coherent detection method and the second is the coherent detection method.
  • the non-coherent detection scheme is such that the phase relationship between signals of the transmitting apparatus and the receiving apparatus is not fixed. Therefore, the receiving apparatus does not need to measure and adjust the phase of the received signal.
  • the coherent detection scheme must be in phase between the transmitter and receiver signals.
  • the receiving device includes the low-power wake-up receiver described above.
  • a low-power wake-up receiver can decode packets (wake-up packets) transmitted using an OOK modulation scheme using an envelope detector to reduce power consumption.
  • the envelope detector measures the power or magnitude of the received signal and decodes it.
  • the receiver sets a threshold based on the power or magnitude measured through the envelope detector. When decoding the symbol to which OOK is applied, information 1 is determined to be greater than or equal to the threshold value, and information 0 is determined to be less than the threshold value.
  • a method for decoding a symbol to which a symbol repetition scheme is applied is as follows.
  • the receiving apparatus can calculate the power or the like when symbol 1 (symbol containing information 1) is transmitted using the wakeup preamble 722 and use it to determine a threshold value.
  • the average power in two symbols is determined to be information 1 (1 1) if it is greater than or equal to a threshold value, and information 0 (0 0) can be determined to be less than a threshold value.
  • the power of two symbols can be compared to determine information without a procedure for determining a threshold value.
  • information 0 is determined if the power of the first symbol is greater than the power of the second symbol. Conversely, if the power of the first symbol is less than the power of the second symbol, it is determined as information 1.
  • the interleaver can be applied in units of a specific number of symbols under a packet unit.
  • n symbols as follows, as well as two symbols. 11 shows various examples of a symbol repetition technique in which n symbols according to the present embodiment are repeated.
  • Option 1 As shown in FIG. 11, information 0 and information 1 can be represented by repeating the same symbol n times.
  • Option 2 As shown in FIG. 11, information 0 and information 1 can be repetitively represented by n symbols with different symbols.
  • Option 3 As shown in FIG. 11, half of the symbols can be composed of information 0 and the other half can be composed of information 1 to represent n symbols.
  • Option 4 As shown in FIG. 11, when n is an odd number, a total of n symbols can be represented by dividing the number of symbols 1 (symbols containing information 1) and the number of symbols 0 (symbols containing information 0).
  • the order of the symbols can be reconstructed by the interleaver.
  • the interleaver can be applied in units of packets and specific symbols.
  • the receiving apparatus can determine whether the information is 0 or 1 by comparing the power of n symbols with the threshold value.
  • the coexistence problem is a problem that occurs when another device determines a channel idle state due to consecutive off-symbols and transmits a signal. Therefore, it is desirable to avoid the use of consecutive off-symbols to solve the problem of solving the problem, so the option of the above option 2 may be preferred.
  • the first or last m is represented by a symbol of 0 (OFF) or 1 (ON) according to information, and a redundant symbol of 0 (OFF) or 1 (ON) can do.
  • the code rate 3/4 is applied to the information 010, it can be 1,010 or 010,1 or 0,010 or 010,0. However, it may be desirable to apply a code rate of 1/2 or less to prevent the use of consecutive off-symbols.
  • the order of the symbols can be reconstructed by the interleaver.
  • the interleaver can be applied in units of packets and specific symbols.
  • symbols with symbol repetition can be represented as n (CP + 3.2us) or CP + n (1.6us).
  • the 3.2 off signal can be generated by applying all coefficients to zero.
  • 1-bit information corresponding to a symbol to which a general symbol repetition technique is applied can be represented as shown in the following table.
  • n (CP + 3.2us) or CP + n (3.2us), including CP can point to a single bit of information. That is, in the case of n (CP + 3.2us), the 3.2us on signal can be regarded as (CP + 3.2us) on signal and the 3.2us off signal can be regarded as (CP + 3.2us) off signal.
  • symbols with symbol repetition technique can be represented as CP + 3.2us + CP + 3.2us or CP + 3.2us + 3.2us.
  • a specific sequence is applied to all available subcarriers (for example, thirteen) representing one bit by using two information signals (symbols), and IFFT is taken to obtain an information signal (symbol) of 3.2 us .
  • the 3.2 off signal can be generated by applying all coefficients to zero.
  • the CP can be used by adopting a specific length behind the information signal 3.2us immediately behind it. At this time, CP may be 0.4us or 0.8us. This length is the same as the guard interval of the 802.11ac.
  • the 1-bit information corresponding to the symbol to which the symbol repetition scheme is applied can be represented as shown in the following table.
  • CP is not indicated separately.
  • CP + 3.2us + CP + 3.2us including CP, or CP + 3.2us + 3.2us may point to a single bit of information.
  • the 3.2us on signal can be regarded as (CP + 3.2us) on signal and the 3.2us off signal can be regarded as (CP + 3.2us) off signal .
  • symbols with symbol repetition can be represented as CP + 3.2us + CP + 3.2us + CP + 3.2us or CP + 3.2us + 3.2us + 3.2us.
  • a specific sequence is applied to all available subcarriers (for example, thirteen) representing one bit by using three information signals (symbols), and IFFT is then taken to obtain an information signal (symbol) of 3.2 us .
  • the 3.2 off signal can be generated by applying all coefficients to zero.
  • the CP can be used by adopting a specific length behind the information signal 3.2us immediately behind it. At this time, CP may be 0.4us or 0.8us. This length is the same as the guard interval of the 802.11ac.
  • the 1-bit information corresponding to the symbol to which the symbol repetition scheme is applied can be represented as shown in the following table.
  • CP is not indicated separately.
  • CP + 3.2us + CP + 3.2us + CP + 3.2us + CP + 3.2us or CP + 3.2us + 3.2us + 3.2us, including CP may point to a single bit of information.
  • the 3.2us on signal can be viewed as (CP + 3.2us) It can be seen as a signal.
  • symbols with symbol repetition can be represented as 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.
  • a specific sequence is applied to all usable subcarriers (for example, thirteen) representing one bit by using four information signals (symbols), and IFFT is then taken to obtain an information signal (symbol) of 3.2 us .
  • the 3.2 off signal can be generated by applying all coefficients to zero.
  • the CP can be used by adopting a specific length behind the information signal 3.2us immediately behind it. At this time, CP may be 0.4us or 0.8us. This length is the same as the guard interval of the 802.11ac.
  • the 1-bit information corresponding to the symbol to which the symbol repetition scheme is applied can be represented as shown in the following table.
  • CP is not indicated separately.
  • 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 containing CP may point to a single bit of information.
  • the 3.2us on signal can be seen as (CP + 3.2us) + 3.2us) off signal.
  • Manchester coded symbols can be represented as n (CP + 1.6us + CP + 1.6us) or CP + n (1.6us + 1.6us).
  • a signal of 3.2us having a period of 1.6us is generated. Take one of them and set it to 1.6us information signal (symbol).
  • the sub information may be called 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 can be applied to different subcarriers.
  • the 1.6us off signal can be generated by applying all coefficients to zero.
  • CP can be used by adopting a specific length behind the information signal 1.6us immediately behind it. At this time, CP may be 0.4us or 0.8us. This length is the same as the guard interval of the 802.11ac.
  • the 1-bit information corresponding to the Manchester-coded symbol based on the symbol repetition can be represented as shown in the following table.
  • CP is not indicated separately.
  • n (CP + 1.6us + CP + 1.6us) or CP + n (1.6us + 1.6us), including CP can point to a single bit of information. That is, in the case of n (CP + 1.6us + CP + 1.6us), the 1.6us ON signal can be viewed as (CP + 1.6us) Can be seen as.
  • the use of symbol repetition techniques can satisfy a range requirement of low power wake up communication.
  • the data rate for one symbol is 250 Kbps (4 us). If the symbols are repeated twice using the symbol repetition technique, the data rate may be 125 Kbps (8 us), the data rate may be 62.5 Kbps (16 us) if it is repeated four times, and the data rate may be 31.25 Kbps have.
  • the symbol can be repeated eight times to satisfy the range requirement.
  • the symbol is further reduced so that the length of a symbol carrying one information is reduced.
  • a certain sequence is applied to all available subcarriers (for example, 13) by a unit of m, representing 1 bit by using a symbol reduction scheme applied symbol, do. If IFFT is applied to the subcarrier to which the specific sequence is applied, a signal of 3.2 us having a period of 3.2 us / m is generated. Take one of them and map it to the 3.2 us / m information signal (information 1).
  • the on-signal can be configured as follows.
  • B0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, e, f, and g are 1 or -1.
  • the on-signal can be configured as follows.
  • the on-signal can be configured as follows.
  • the 3.2us / m information signal is divided into 3.2us / m on signal and 3.2us / m off signal.
  • the 3.2 us / m on signal and the 3.2 us / m off signal can each have different sequences applied to (available) subcarriers.
  • the 3.2 us / 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 can be represented as shown in the following table.
  • CP is not indicated separately.
  • CP + 3.2us / m can point to a single bit of information.
  • the 3.2us / m on signal can be viewed as CP + 3.2us / m on signal
  • the 3.2us / m off signal can be seen as CP + 3.2us / m off signal.
  • the time used for transmission of one bit (or symbol) excluding the guard interval of the transmission signal is 3.2us.
  • the time used for one bit transmission is 3.2 us / m.
  • the time to be used for one bit transmission is set to 3.2 us / m + 3.2 us / m by repeating the symbols with the symbol reduction technique applied thereto, Size transition. That is, each sub-information having a length of 3.2 us / m should have a value of 0 or 1, and a signal can be constructed in the following manner.
  • sub information 1 or sub symbol 1 for every available subcarrier (e.g., 13 subcarriers) to generate a symbol with symbol reduction technique, Is applied. That is, a particular sequence may have coefficients at intervals of m squares.
  • the transmitter performs IFFT by mapping a specific sequence to consecutive K subcarriers among 64 subcarriers and setting a coefficient to 0 for the remaining subcarriers.
  • a signal in the time domain can be generated. Since the signal in the time domain has a coefficient at intervals of m cells in the frequency domain, a signal of 3.2us having a period of 3.2us / m is generated. You can take one of these and use it as a 3.2 us / m on signal (sub information 1).
  • the second 3.2 us / m signal (sub information 0 or sub symbol 0):
  • the transmitter maps a specific sequence to consecutive K subcarriers out of 64 subcarriers, So that a signal in the time domain can be generated.
  • Sub information 0 can correspond to a 3.2 us / m off signal.
  • the 3.2 us / m off signal can be generated by setting all coefficients to zero.
  • One of the first or second 3.2 us / m periodic signals of the time domain signal may be selected and used as the sub information 0.
  • the information 0 may be composed of 01 and the information 1 may be composed of 10.
  • the 1-bit information corresponding to the symbols to which the symbol reduction technique is applied can be represented as shown in the following table.
  • CP is not indicated separately.
  • CP + 3.2us / m can point to a single bit of information.
  • the 3.2us / m on signal can be viewed as CP + 3.2us / m on signal
  • the 3.2us / m off signal can be seen as CP + 3.2us / m off signal.
  • each signal is represented by a length including CP. That is, CP + 3.2us / m including CP can indicate one 1-bit information.
  • the length of a symbol carrying information is CP + 0.8us, so 1us off signal or 1us on signal consists of CP (0.2us) + 0.8us signal.
  • the data rate for one piece of information can be 500 Kbps.
  • the length of a symbol carrying information is CP + 0.4us, so 0.5us off signal or 0.5us on signal consists of CP (0.1us) + 0.4us signal.
  • FIG. 13 shows an example of configuring the 2us on signal based on signal masking according to the present embodiment.
  • the data rate can be secured according to various symbol types that can be used in WUR.
  • a method for generating a 2us on signal may be proposed to secure a data rate of 250 Kbps.
  • FIG. 13 proposes a masking-based technique using a sequence of length 13 (a coefficient is inserted into all 13 consecutive subcarriers in the 20 MHz band).
  • 4us OOK symbols can be generated.
  • a sequence of length 13 is applied to 13 consecutive subcarriers in the 20 MHz band to perform a 64-point IFFT, and a 4us OOK symbol is generated by adding 0.8 us CP or GI.
  • the 2us on signal can be constructed by masking half of the 4us OOK symbol.
  • the information 0 can constitute a 2us on signal by taking a half of a 4us symbol.
  • the half of the 4us symbol does not transmit any information, so a 2us off signal can be constructed.
  • information 1 can constitute a 2 os signal by taking the latter half of the symbol.
  • a half of the 4us symbol does not transmit any information, so it can constitute a 2us off signal.
  • various data rates in an 802.11ba system can be applied to the payload of the WUR PPDU and two types of sync parts or sync fields of different lengths are used to reduce the overhead of the WUR PPDU. Can be used to configure the WUR PPDU.
  • FIG 14 shows an example of a wakeup packet structure to which different sync parts are applied according to the present embodiment.
  • Each of Sync 1 and Sync 2 is formed with a sequence having the same number of 1's and 0's (or -1's) and can be designed to have good auto-correlation properties, the cross-correlation value is designed to have a small value so that it is easy to distinguish which sync is applied to the PPDU at the receiving end. (The receiver simultaneously performs cross-correlation of the received signal using the sequence of sync 1 and 2), which can be used to indicate two data rates without additional PHY signaling.
  • sync 1 can be used for WUR PPDUs with a data rate of 62.5 kbps on the payload using long sequences and symbols. It can also be used for WUR PPDUs with a data rate of 250kbps in the payload using relatively short sequences and symbols.
  • the present invention proposes a frequency domain sequence having a length of 13 used for generating a 4us ON-signal used in a data rate of 62.5kbps in the IEEE 802.11b system.
  • the frequency domain sequence used in 11ac is BPSK, QPSK, 16QAM, 64QAM, 256QAM
  • PAPR Peak-to-Average Power Ratio
  • the present invention proposes a frequency domain sequence having a length of 7, which is used for 2us ON-signal generation at a data rate of 250kbps in the IEEE 802.11b system.
  • BPSK, QPSK, 16QAM, 64QAM We propose a method of constructing a sequence from PAPR minimization point by using constellation point of 256QAM.
  • LDR refers to WUR low data rate and means 62.5kbps.
  • HDR WUR-HDR indicates a WUR high data rate, which means 250 kbps.
  • SymLDROn means 4us On-signal and SymLDROff means 4us Off-signal.
  • SymHDROn means 2us On-signal and SymHDROff means 2us Off-signal.
  • the transmitter can generate 2us / 4us On-signal using existing Wi-Fi 20MHz OFDM transmission. Since WUR uses about 4MHz signal bandwidth, 13 of 64 subcarriers are used. That is, a 4-on-signal can be generated by applying a sequence of length 13 to 13 subcarriers and 0 to the remaining 51 subcarriers, applying appropriate power scaling, 64 point IFFT and 0.8us cyclic prefix.
  • the transmitting device applies a length sequence of 7 (13, 5, 7, 9, 11, 13) to 13 subcarriers in units of 7 lengths and assigns a coefficient of 0 to the remainder and then applies appropriate power scaling and 64 point IFFT A 3.2us signal with a period of 1.6us is generated and the first or last 1.6us signal is selected and a 0.4us cyclic prefix is applied to generate a 2us On-signal.
  • 7 subcarriers correspond to the 4 MHz band, and 7 length sequences are applied to the subcarriers.
  • the remaining coefficients are set to 0, and then the power scaling and 32 point IFFT and 0.4us
  • the cyclic prefix can be applied to generate 2us on-signal.
  • 15 shows a constellation diagram of BPSK modulation.
  • 16 shows a constellation diagram of QPSK modulation.
  • 17 shows a constellation diagram of 16QAM modulation.
  • 19 to 22 show constellations of 256QAM modulation.
  • 19 shows the first quadrant of the 256QAM constellation.
  • 20 shows a second quadrant of the 256QAM constellation.
  • 21 shows a third quadrant of the 256QAM constellation diagram.
  • 22 shows a fourth quadrant of the 256QAM constellation.
  • Modulation K MOD BPSK One QPSK 1 / ⁇ 2 16QAM 1 / ⁇ 10 64QAM 1 / ⁇ 42 256QAM 1 / ⁇ 170
  • K MOD represents a value at which the average power of the constellation point becomes 1.
  • the sequence that minimizes the PAPR is as follows, and the PAPR is 2.0589 dB.
  • sequence after the change of order has the same PAPR.
  • phase rotation has the same PAPR.
  • the 13 length sequences can be multiplied by a specific power normalization value.
  • the K MOD or K MOD * sqrt (64) corresponding to the BPSK in the above table may be multiplied.
  • 1 / sqrt (12) or sqrt (64/12) may be multiplied to make the average energy of the sequence equal to 1, taking into account only 13 length sequences instead of the total constellation.
  • the sequence that minimizes the PAPR is as follows, and the PAPR is 2.0589 dB.
  • sequence after the change of order has the same PAPR.
  • phase rotation has the same PAPR.
  • the 13 length sequences can be multiplied by a specific power normalization value.
  • the K MOD or K MOD * sqrt (64) corresponding to the QPSK in the above table may be multiplied.
  • 1 / sqrt (12) or sqrt (64/12) may be multiplied to make the average energy of the sequence equal to 1, taking into account only 13 length sequences instead of the total constellation.
  • This method first fixes the first coefficient to one value and finds a second coefficient that minimizes the PAPR. Then, we obtain a third coefficient that minimizes the PAPR in the given first and second coefficients. That is, this is a method of constructing 13 length sequences by repeating this.
  • the reference coefficient can be the first coefficient at the beginning of the sequence.
  • sequence after the change of order has the same PAPR.
  • phase rotation has the same PAPR.
  • the 13 length sequences can be multiplied by a specific power normalization value.
  • the K MOD or K MOD * sqrt (64) corresponding to the BPSK in the above table may be multiplied.
  • 1 / sqrt (12) or sqrt (64/12) may be multiplied to make the average energy of the sequence equal to 1, taking into account only 13 length sequences instead of the total constellation.
  • sequence after the change of order has the same PAPR.
  • phase rotation has the same PAPR.
  • the 13 length sequences can be multiplied by a specific power normalization value.
  • the K MOD or K MOD * sqrt (64) corresponding to the QPSK in the above table may be multiplied.
  • 1 / sqrt (12) or sqrt (64/12) may be multiplied to make the average energy of the sequence equal to 1, taking into account only 13 length sequences instead of the total constellation.
  • sequence after the change of order has the same PAPR.
  • phase rotation has the same PAPR.
  • the 13 length sequences can be multiplied by a specific power normalization value.
  • the K MOD or K MOD * sqrt (64) corresponding to 16QAM in the above table may be multiplied.
  • 1 / sqrt (72) or sqrt (64/72) may be multiplied to make the average energy of the sequence equal to 1, taking into account only 13 length sequences rather than the total constellation.
  • sequence after the change of order has the same PAPR.
  • phase rotation has the same PAPR.
  • the 13 length sequences can be multiplied by a specific power normalization value.
  • the K MOD or K MOD * sqrt (64) corresponding to 64QAM in the above table may be multiplied.
  • 1 / sqrt (120) or sqrt (64/120) may be multiplied to make the average energy of the sequence to be 1, considering only 13 sequence lengths rather than the total constellation.
  • the sequence found in this way is as follows and the PAPR is 1.3904 dB.
  • sequence after the change of order has the same PAPR.
  • phase rotation has the same PAPR.
  • the 13 length sequences can be multiplied by a specific power normalization value.
  • the K MOD or K MOD * sqrt (64) corresponding to 256QAM in the above table may be multiplied.
  • 1 / sqrt (472) or sqrt (64/472) may be multiplied to make the average energy of the sequence to be 1, taking into account only 13 length sequences rather than the total constellation.
  • each coefficient consists of constellation points of BPSK, QPSK, 16QAM, 64QAM, and 256QAM used in 11ac.
  • the constellation points shown in Figs. 15 to 22 are used.
  • the sequence that minimizes the PAPR is as follows, and the PAPR is 2.2377 dB.
  • sequence after the change of order has the same PAPR.
  • phase rotation has the same PAPR.
  • the 7 length sequence can be multiplied by a specific power normalization value.
  • the K MOD or K MOD * sqrt (64) corresponding to the BPSK in the above table may be multiplied.
  • 1 / sqrt (6) or sqrt (64/6) may be multiplied to get the average energy of the sequence to be 1, taking into account only 7 sequence lengths rather than the total constellation.
  • the sequence that minimizes the PAPR is as follows, and the PAPR is 2.2377 dB.
  • sequence after the change of order has the same PAPR.
  • phase rotation has the same PAPR.
  • the 7 length sequence can be multiplied by a specific power normalization value.
  • the K MOD or K MOD * sqrt (64) corresponding to the QPSK in the above table may be multiplied.
  • 1 / sqrt (12) or sqrt (64/12) may be multiplied to get the average energy of the sequence to be 1, taking into account only 7 sequence lengths rather than the entire constellation.
  • the sequence that minimizes the PAPR is as follows, and the PAPR is 0.7329 dB.
  • sequence after the change of order has the same PAPR.
  • phase rotation has the same PAPR.
  • the 7 length sequence can be multiplied by a specific power normalization value.
  • the K MOD or K MOD * sqrt (64) corresponding to 16QAM in the above table may be multiplied.
  • 1 / sqrt (44) or sqrt (64/44) may be multiplied to make the average energy of the sequence equal to 1, taking into account only the 7 length sequences rather than the total constellation.
  • This method first fixes the first coefficient to one value and finds a second coefficient that minimizes the PAPR. Then, we obtain a third coefficient that minimizes the PAPR in the given first and second coefficients. That is, it is a method to construct 7 length sequences by repeating this.
  • the reference coefficient can be the first coefficient at the beginning of the sequence.
  • the sequence found by this method is as follows and the PAPR is 4.2597 dB.
  • sequence after the change of order has the same PAPR.
  • phase rotation has the same PAPR.
  • the 7 length sequence can be multiplied by a specific power normalization value.
  • the K MOD or K MOD * sqrt (64) corresponding to the BPSK in the above table may be multiplied.
  • 1 / sqrt (6) or sqrt (64/6) may be multiplied to get the average energy of the sequence to be 1, taking into account only 7 sequence lengths rather than the total constellation.
  • the sequence found by this method is as follows and the PAPR is 4.0959 dB.
  • sequence after the change of order has the same PAPR.
  • phase rotation has the same PAPR.
  • the 7 length sequence can be multiplied by a specific power normalization value.
  • the K MOD or K MOD * sqrt (64) corresponding to the QPSK in the above table may be multiplied.
  • 1 / sqrt (12) or sqrt (64/12) may be multiplied to get the average energy of the sequence to be 1, taking into account only 7 sequence lengths rather than the entire constellation.
  • the sequence found by this method is as follows and the PAPR is 2.2603 dB.
  • sequence after the change of order has the same PAPR.
  • phase rotation has the same PAPR.
  • the 7 length sequence can be multiplied by a specific power normalization value.
  • the K MOD or K MOD * sqrt (64) corresponding to 16QAM in the above table may be multiplied.
  • 1 / sqrt (28) or sqrt (64/28) may be multiplied to make the average energy of the sequence equal to 1, taking into account only 7 sequence lengths rather than the total constellation.
  • sequence after the change of order has the same PAPR.
  • phase rotation has the same PAPR.
  • the 7 length sequence can be multiplied by a specific power normalization value.
  • the K MOD or K MOD * sqrt (64) corresponding to 64QAM in the above table may be multiplied.
  • 1 / sqrt (108) or sqrt (64/108) may be multiplied to make the average energy of the sequence to be 1, taking into account only the 7 length sequences rather than the overall constellation.
  • the sequence found by this method is as follows and the PAPR is 0.8123 dB.
  • sequence after the change of order has the same PAPR.
  • phase rotation has the same PAPR.
  • the 7 length sequence can be multiplied by a specific power normalization value.
  • the K MOD or K MOD * sqrt (64) corresponding to 256QAM in the above table may be multiplied.
  • 1 / sqrt (450) or sqrt (64/450) may be multiplied to make the average energy of the sequence to be 1, taking into account only 7 sequence lengths rather than the total constellation.
  • FIG. 23 is a flowchart illustrating a procedure for transmitting a wakeup packet by applying the OOK scheme according to the present embodiment.
  • FIG. 23 may be performed in a transmitting apparatus, a receiving apparatus may correspond to a low power wakeup receiver, and a transmitting apparatus may correspond to an AP.
  • the on signal can correspond to a signal having an actual power value.
  • An off signal may correspond to a signal that does not have an actual power value.
  • step S2310 the transmitting apparatus constructs a wakeup packet by applying an On-Off Keying (OOK) method.
  • OOK On-Off Keying
  • step S2320 the transmitting apparatus transmits the wakeup packet to the receiving apparatus.
  • the configuration of the wakeup packet in this embodiment is as follows.
  • the wakeup packet includes an ON signal and an OFF signal.
  • the on-signal is generated by inserting a first sequence into 13 consecutive subcarriers in the 20 MHz band and performing 64-point IFFT (Inverse Fast Fourier Transform).
  • the concrete procedure of generating the on-signal is as follows.
  • the number of coefficients of the first sequence is seven.
  • the coefficients of the first sequence are inserted into each of the 13 subcarriers for every 2 subcarriers. Since the number of coefficients of the first sequence is not 13, it can not be inserted one-to-one into thirteen subcarriers. Therefore, assuming that the index (1 to 13) of 13 coefficients is assigned to the coefficient (7) of the first sequence, a subcarrier having an index of 1, 3, 5, 7, 9, 11, As shown in FIG.
  • 0 can be inserted in a subcarrier in which coefficients of the first sequence are not inserted. That is, 0 can be inserted into subcarriers having indexes of 2, 4, 6, 8, 10, and 12 among the 13 subcarriers.
  • the DC subcarrier (middle subcarrier) can be set to zero.
  • the on-signal may be generated by inserting a CP (Cyclic Prefix) after masking half of the generated signal by inserting the first sequence into the 13 subcarriers and performing 64-point IFFT.
  • the signal generated by performing the 64-point IFFT may be a 3.2 us signal having a period of 1.6 us. If the first or last 1.6 us signal among the 3.2 us signals having a period of 1.6 us is selected (half is masked) and a 0.4us CP is inserted, an on signal of 2us can be generated.
  • the data rate of the wakeup packet is 250 Kbps
  • the length of the ON signal is 2 us
  • the length of the CP may be 0.4 us.
  • the coefficients of the first sequence are set to one of values indicated by a constellation point of 16 QAM (Quadrature Amplitude Modulation).
  • the 16 QAM may be a modulation scheme used in an 802.11ac system.
  • the value indicated by the constellation point of the 16 QAM is 1 + j, -1 + j, -1-j, 1-j, 3 + j, -3 + j, 3j, -1 + 3j, -1-3j, 1-3j, 3 + 3j, -3 + 3j, -3-3j and 3-3j.
  • the sequence for minimizing PAPR is as follows.
  • the first sequence may be set to a second sequence, and the second sequence may be [1 + j, 3 + j, 3-j, 0, -1 + 3j, -1-3j, 1 + j].
  • the Peak-to-Average Power Ratio (PAPR) of the second sequence may be 0.7239 dB. That is, the PAPR can be minimized when using the second sequence.
  • the first sequence may be set to a sequence obtained by multiplying the second sequence by -1, j, or -j and applying phase rotation. Even if a phase rotation is applied, it may have the same PAPR as that used in the second sequence.
  • the power normalization value of the first sequence may be 1 / sqrt (44).
  • the power normalization value may be a value such that the average power of the first sequence is unity. That is, instead of considering the total constellation point of 16 QAM, only 1 / sqrt (44) may be multiplied so that the average energy of the first sequence becomes 1 considering only the first sequence having a length of 7.
  • the number of coefficients of the first sequence may be 13. At this time, the coefficients of the first sequence may be inserted one-to-one among the 13 subcarriers. However, the DC subcarrier (middle subcarrier) can be set to zero.
  • the on-signal may be generated by inserting the first sequence (length 13) into the 13 subcarriers and inserting a CP into the generated signal by performing 64-point IFFT.
  • the signal generated by performing the 64-point IFFT is 3.2us signal, and when the CP of 0.8us is inserted, the on-signal of 4us can be generated.
  • the data rate of the wakeup packet is 62.5 Kbps
  • the length of the ON signal is 4us
  • the length of the CP may be 0.8us.
  • the coefficient of the first sequence can be set to a value indicated by constellation points of BPSK, QPSK, 16QAM, and 256QAM in the 802.11ac system.
  • Each modulation scheme is set as a coefficient of a sequence used in the 802.11 ba system has been described above.
  • the coefficients of the first sequence may be set to one of the values indicated by the constellation point of QPSK.
  • the first sequence that minimizes the PAPR is [1 + j, -1-j, 1 + j, 1 + j, -1-j, 1 + j, 0, 1 + j, -1-j, -1-j, -1-j].
  • the transmitting apparatus can configure the ON signal and the OFF signal to know the power value of the ON signal and the OFF signal first.
  • the receiving apparatus decodes the ON signal and the OFF signal using an envelope detector, thereby reducing power consumed in decoding.
  • a wireless device is a transmitting device capable of implementing the above-described embodiment, and can operate as an AP.
  • the wireless device may correspond to a transmitting device that transmits a signal to a user.
  • processor 24 includes a processor 2410, a memory 2420, and a transceiver 2430 as shown.
  • the illustrated processor 2410, memory 2420 and transceiver 2430 may each be implemented as separate chips, or at least two blocks / functions may be implemented on a single chip.
  • the transceiver 2430 is a device including a transmitter and a receiver. When a specific operation is performed, only the operation of either the transmitter or the receiver is performed, or both the transmitter and the receiver are operated .
  • the transceiver 2430 may include one or more antennas for transmitting and / or receiving wireless signals.
  • the transceiver 2430 may include an amplifier for amplifying a received signal and / or a transmission signal, and a band-pass filter for transmission on a specific frequency band.
  • the processor 2410 may implement the functions, processes, and / or methods suggested herein. For example, the processor 2410 may perform the operations according to the embodiment described above. That is, the processor 2410 constructs a wakeup packet by applying an on-off keying (OOK) method, and transmits the wakeup packet to the receiving apparatus.
  • OOK on-off keying
  • the configuration of the wakeup packet in this embodiment is as follows.
  • the wakeup packet includes an ON signal and an OFF signal.
  • the on-signal is generated by inserting a first sequence into 13 consecutive subcarriers in the 20 MHz band and performing 64-point IFFT (Inverse Fast Fourier Transform).
  • the concrete procedure of generating the on-signal is as follows.
  • the number of coefficients of the first sequence is seven.
  • the coefficients of the first sequence are inserted into each of the 13 subcarriers for every 2 subcarriers. Since the number of coefficients of the first sequence is not 13, it can not be inserted one-to-one into thirteen subcarriers. Therefore, assuming that the index (1 to 13) of 13 coefficients is assigned to the coefficient (7) of the first sequence, a subcarrier having an index of 1, 3, 5, 7, 9, 11, As shown in FIG.
  • 0 can be inserted in a subcarrier in which coefficients of the first sequence are not inserted. That is, 0 can be inserted into subcarriers having indexes of 2, 4, 6, 8, 10, and 12 among the 13 subcarriers.
  • the DC subcarrier (middle subcarrier) can be set to zero.
  • the on-signal may be generated by inserting a CP (Cyclic Prefix) after masking half of the generated signal by inserting the first sequence into the 13 subcarriers and performing 64-point IFFT.
  • the signal generated by performing the 64-point IFFT may be a 3.2 us signal having a period of 1.6 us. If the first or last 1.6 us signal among the 3.2 us signals having a period of 1.6 us is selected (half is masked) and a 0.4us CP is inserted, an on signal of 2us can be generated.
  • the data rate of the wakeup packet is 250 Kbps
  • the length of the ON signal is 2 us
  • the length of the CP may be 0.4 us.
  • the coefficients of the first sequence are set to one of values indicated by a constellation point of 16 QAM (Quadrature Amplitude Modulation).
  • the 16 QAM may be a modulation scheme used in an 802.11ac system.
  • the value indicated by the constellation point of the 16 QAM is 1 + j, -1 + j, -1-j, 1-j, 3 + j, -3 + j, 3j, -1 + 3j, -1-3j, 1-3j, 3 + 3j, -3 + 3j, -3-3j and 3-3j.
  • the sequence for minimizing PAPR is as follows.
  • the first sequence may be set to a second sequence, and the second sequence may be [1 + j, 3 + j, 3-j, 0, -1 + 3j, -1-3j, 1 + j].
  • the Peak-to-Average Power Ratio (PAPR) of the second sequence may be 0.7239 dB. That is, the PAPR can be minimized when using the second sequence.
  • the first sequence may be set to a sequence obtained by multiplying the second sequence by -1, j, or -j and applying phase rotation. Even if a phase rotation is applied, it may have the same PAPR as that used in the second sequence.
  • the power normalization value of the first sequence may be 1 / sqrt (44).
  • the power normalization value may be a value such that the average power of the first sequence is unity. That is, instead of considering the total constellation point of 16 QAM, only 1 / sqrt (44) may be multiplied so that the average energy of the first sequence becomes 1 considering only the first sequence having a length of 7.
  • the processor 2410 may include an application-specific integrated circuit (ASIC), another chipset, a logic circuit, a data processing device, and / or a converter for converting baseband signals and radio signals.
  • Memory 2420 may include read-only memory (ROM), random access memory (RAM), flash memory, memory cards, storage media, and / or other storage devices.
  • FIG. 25 shows a procedure for transmitting a WUR PPDU configured by applying an OOK scheme between an AP and a WUR STA according to the present embodiment.
  • Fig. 25 may be performed in the transmitting apparatus and the receiving apparatus, the receiving apparatus may correspond to the low power wake up receiver (WUR STA), and the transmitting apparatus may correspond to the AP.
  • WUR STA low power wake up receiver
  • the on signal can correspond to a signal having an actual power value.
  • An off signal may correspond to a signal that does not have an actual power value.
  • step S2510 the AP constructs a wakeup packet by applying the OOK scheme.
  • step S2520 the AP transmits the wakeup packet to the WUR STA.
  • the configuration of the wakeup packet in this embodiment is as follows.
  • the wakeup packet includes an ON signal and an OFF signal.
  • the on-signal is generated by inserting a first sequence into 13 consecutive subcarriers in the 20 MHz band and performing 64-point IFFT (Inverse Fast Fourier Transform).
  • the concrete procedure of generating the on-signal is as follows.
  • the number of coefficients of the first sequence is seven.
  • the coefficients of the first sequence are inserted into each of the 13 subcarriers for every 2 subcarriers. Since the number of coefficients of the first sequence is not 13, it can not be inserted one-to-one into thirteen subcarriers. Therefore, assuming that the index (1 to 13) of 13 coefficients is assigned to the coefficient (7) of the first sequence, a subcarrier having an index of 1, 3, 5, 7, 9, 11, As shown in FIG.
  • 0 can be inserted in a subcarrier in which coefficients of the first sequence are not inserted. That is, 0 can be inserted into subcarriers having indexes of 2, 4, 6, 8, 10, and 12 among the 13 subcarriers.
  • the DC subcarrier (middle subcarrier) can be set to zero.
  • the on-signal may be generated by inserting a CP (Cyclic Prefix) after masking half of the generated signal by inserting the first sequence into the 13 subcarriers and performing 64-point IFFT.
  • the signal generated by performing the 64-point IFFT may be a 3.2 us signal having a period of 1.6 us. If the first or last 1.6 us signal among the 3.2 us signals having a period of 1.6 us is selected (half is masked) and a 0.4us CP is inserted, an on signal of 2us can be generated.
  • the data rate of the wakeup packet is 250 Kbps
  • the length of the ON signal is 2 us
  • the length of the CP may be 0.4 us.
  • the coefficients of the first sequence are set to one of values indicated by a constellation point of 16 QAM (Quadrature Amplitude Modulation).
  • the 16 QAM may be a modulation scheme used in an 802.11ac system.
  • the value indicated by the constellation point of the 16 QAM is 1 + j, -1 + j, -1-j, 1-j, 3 + j, -3 + j, 3j, -1 + 3j, -1-3j, 1-3j, 3 + 3j, -3 + 3j, -3-3j and 3-3j.
  • the sequence for minimizing PAPR is as follows.
  • the first sequence may be set to a second sequence, and the second sequence may be [1 + j, 3 + j, 3-j, 0, -1 + 3j, -1-3j, 1 + j].
  • the Peak-to-Average Power Ratio (PAPR) of the second sequence may be 0.7239 dB. That is, the PAPR can be minimized when using the second sequence.
  • the first sequence may be set to a sequence obtained by multiplying the second sequence by -1, j, or -j and applying phase rotation. Even if a phase rotation is applied, it may have the same PAPR as that used in the second sequence.
  • the power normalization value of the first sequence may be 1 / sqrt (44).
  • the power normalization value may be a value such that the average power of the first sequence is unity. That is, instead of considering the total constellation point of 16 QAM, only 1 / sqrt (44) may be multiplied so that the average energy of the first sequence becomes 1 considering only the first sequence having a length of 7.
  • 26 shows a receiving apparatus for implementing this embodiment.
  • a wireless device is a receiving device capable of implementing the above-described embodiment, and can operate as a non-AP STA or a WUR STA. Also, the wireless device may correspond to the above-described user.
  • processor 26 includes a processor 2610, a memory 2620, and a transceiver 2630 as shown.
  • the illustrated processor 2610, memory 2620, and transceiver 2630 may each be implemented as separate chips, or at least two blocks / functions may be implemented on a single chip.
  • the transceiver 2630 is a device including a transmitter and a receiver. When a specific operation is performed, only the operation of either the transmitter or the receiver is performed, or both the transmitter and the receiver are performed .
  • the transceiver 2630 may include one or more antennas for transmitting and / or receiving wireless signals.
  • the transceiver 2630 may include an amplifier for amplifying a received signal and / or a transmission signal, and a band-pass filter for transmitting on a specific frequency band.
  • the processor 2610 may implement the functions, processes, and / or methods suggested herein. For example, the processor 2610 may perform the operations according to the embodiment described above. That is, the processor 2610 receives the wakeup packet to which the OOK scheme configured by the transmitting apparatus is applied.
  • the configuration of the wakeup packet in this embodiment is as follows.
  • the wakeup packet includes an ON signal and an OFF signal.
  • the on-signal is generated by inserting a first sequence into 13 consecutive subcarriers in the 20 MHz band and performing 64-point IFFT (Inverse Fast Fourier Transform).
  • the concrete procedure of generating the on-signal is as follows.
  • the number of coefficients of the first sequence is seven.
  • the coefficients of the first sequence are inserted into each of the 13 subcarriers for every 2 subcarriers. Since the number of coefficients of the first sequence is not 13, it can not be inserted one-to-one into thirteen subcarriers. Therefore, assuming that the index (1 to 13) of 13 coefficients is assigned to the coefficient (7) of the first sequence, a subcarrier having an index of 1, 3, 5, 7, 9, 11, As shown in FIG.
  • 0 can be inserted in a subcarrier in which coefficients of the first sequence are not inserted. That is, 0 can be inserted into subcarriers having indexes of 2, 4, 6, 8, 10, and 12 among the 13 subcarriers.
  • the DC subcarrier (middle subcarrier) can be set to zero.
  • the on-signal may be generated by inserting a CP (Cyclic Prefix) after masking half of the generated signal by inserting the first sequence into the 13 subcarriers and performing 64-point IFFT.
  • the signal generated by performing the 64-point IFFT may be a 3.2 us signal having a period of 1.6 us. If the first or last 1.6 us signal among the 3.2 us signals having a period of 1.6 us is selected (half is masked) and a 0.4us CP is inserted, an on signal of 2us can be generated.
  • the data rate of the wakeup packet is 250 Kbps
  • the length of the ON signal is 2 us
  • the length of the CP may be 0.4 us.
  • the coefficients of the first sequence are set to one of values indicated by a constellation point of 16 QAM (Quadrature Amplitude Modulation).
  • the 16 QAM may be a modulation scheme used in an 802.11ac system.
  • the value indicated by the constellation point of the 16 QAM is 1 + j, -1 + j, -1-j, 1-j, 3 + j, -3 + j, 3j, -1 + 3j, -1-3j, 1-3j, 3 + 3j, -3 + 3j, -3-3j and 3-3j.
  • the sequence for minimizing PAPR is as follows.
  • the first sequence may be set to a second sequence, and the second sequence may be [1 + j, 3 + j, 3-j, 0, -1 + 3j, -1-3j, 1 + j].
  • the Peak-to-Average Power Ratio (PAPR) of the second sequence may be 0.7239 dB. That is, the PAPR can be minimized when using the second sequence.
  • the first sequence may be set to a sequence obtained by multiplying the second sequence by -1, j, or -j and applying phase rotation. Even if a phase rotation is applied, it may have the same PAPR as that used in the second sequence.
  • the power normalization value of the first sequence may be 1 / sqrt (44).
  • the power normalization value may be a value such that the average power of the first sequence is unity. That is, instead of considering the total constellation point of 16 QAM, only 1 / sqrt (44) may be multiplied so that the average energy of the first sequence becomes 1 considering only the first sequence having a length of 7.
  • the processor 2610 may include an application-specific integrated circuit (ASIC), another chipset, logic circuitry, a data processing device, and / or a transducer to convert baseband signals and radio signals.
  • Memory 2620 may include read-only memory (ROM), random access memory (RAM), flash memory, memory cards, storage media, and / or other storage devices.

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Abstract

L'invention concerne un procédé et un appareil de transmission d'un paquet de réveil en appliquant un schéma de modulation par tout ou rien (OOK) dans un système de réseau local sans fil. Plus précisément, l'appareil de transmission construit un paquet de réveil en appliquant le schéma OOK. L'appareil de transmission transmet le paquet de réveil à un appareil de réception. Le paquet de réveil contient un signal de marche et un signal d'arrêt. Le signal de marche est généré en insérant une première séquence dans 13 sous-porteuses consécutives dans une bande de 20 MHz et en réalisant une IFFT à 64 points. Le nombre de coefficients de la première séquence est de sept. Les coefficients de la première séquence sont insérés dans deux sous-porteuses toutes les 13 sous-porteuses. Les coefficients de la première séquence sont fixés à l'une des valeurs indiquées par un point de constellation de MAQ 16.
PCT/KR2019/000813 2018-01-23 2019-01-21 Procédé et appareil de transmission de paquet de réveil dans un système de réseau local sans fil Ceased WO2019146969A1 (fr)

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