WO2019177299A1 - Method and apparatus for transmitting wakeup packet in wireless lan system - Google Patents

Abstract

A method and an apparatus for transmitting a wakeup packet by applying the OOK scheme to a wireless LAN system are proposed. Specifically, a transmitting apparatus generates a first wakeup packet having a first data rate and a second wakeup packet having a second data rate. The transmitting apparatus transmits the first wakeup packet on a first band and the second wakeup packet on a second band.

Description

Method and apparatus for transmitting wake-up packet in WLAN system

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.

Discussion is underway for the next generation wireless local area network (WLAN). In 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.

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. In addition, in the 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.

Specifically, in the 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. And STA are discussing about improving system performance in a dense environment with many STAs.

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.

The present specification proposes a method and apparatus for transmitting a wake-up packet by applying a OOK scheme in a WLAN system.

An example of the present specification proposes a method and apparatus for transmitting a wake-up packet to a WLAN system.

This embodiment is performed in a transmitter, the receiver may correspond to a low power wake-up receiver, and the transmitter may correspond to an AP. This embodiment describes a case where a wake-up packet transmitted to wake up a primary radio is transmitted to a plurality of receivers through a plurality of bands (multi-band or multi-channel). The transmission of the WUR PPDU through a plurality of bands may be regarded as the transmission of a WUR PPDU per 20 MHz in a plurality of bands by applying a frequency division multiplexing access (FDMA) scheme. Therefore, this embodiment can be said that WUR FDMA is applied.

First of all, the term “on signal” may correspond to a signal having an actual power value. The off signal may correspond to a signal that does not have an actual power value. The plurality of bands may be 40 MHz, 80 MHz, or 160 MHz.

The transmitter generates a first wakeup packet having a first data rate and a second wakeup packet having a second data rate.

The transmitter transmits the first wakeup packet through a first band and the second wakeup packet through a second band.

How the wakeup packet is configured in the present embodiment is as follows.

On-Off Keying (OOK) is applied to the first and second wake-up packets. The first wakeup packet includes a first on signal or a first off signal. The second wakeup packet includes a second on signal or a second off signal.

The first on signal is generated by inserting a first sequence into 13 consecutive subcarriers in the first band and performing an inverse fast fourier transform (IFFT). The second on signal is generated by inserting a second sequence into 13 consecutive subcarriers in the second band and performing IFFT.

The length of the first and second sequences is seven. However, data rates of the first and second wakeup packets are different. For example, the first data rate may be 250 Kbps, and the second data rate may be 62.5 Kbps. At 250 Kbps, it is HDR (High Data Rate). At 62.5 Kbps, it is Low Data Rate (LDR). In 802.11ba, a 2us long on-signal is generated using a 7-length sequence in the case of HDR, and a 4us long on-signal is generated using a 13-length sequence in the case of an LDR.

In the present embodiment, HDR may be applied to some of the first to second bands, and LDR may be applied to other portions. Therefore, forming a 2us on signal (or 2us waveform) is preferable in terms of implementation, PAPR, and performance. That is, the transmitting device may perform a single IFFT to form a 2us on signal that is a basic signal unit.

Therefore, in the present embodiment, it is assumed that LDR is also generated by using a sequence of length 7 as in the case of HDR by configuring an on signal having a 4us length as a 2us on signal + a 2us on signal. Similarly, in the case of LDR, the 4us long off signal may be configured as a 2us off signal + a 2us off signal.

For example, when the entire band is 40 MHz, the first band is the first 20 MHz of the 40 MHz, and the second band is the second 20 MHz of the 40 MHz, the coefficient of the first sequence is a subcarrier index Inserted into a subcarrier of -38, -36, -34, -32, -30, -28, or -26, and the coefficient of the second sequence has a subcarrier index of 26, 28, 30, 32, 34, 36, It is inserted into a subcarrier of 38. That is, since the lengths of the first and second sequences are seven, it can be seen that they are actually inserted into seven subcarriers. Accordingly, 0 is inserted in a subcarrier in which the coefficients of the first sequence are not inserted in 13 consecutive subcarriers in the first band and 0 in the 13 consecutive subcarriers in the second band. Zero subcarriers may be inserted for subcarriers without coefficients.

When transmitting a wake-up packet through a plurality of bands, the entire subbands and subcarrier indexes for each band may be determined as follows.

In the first embodiment, it is assumed that the entire band is 40 MHz, the first band is the first 20 MHz of the 40 MHz, and the second band is the second 20 MHz of the 40 MHz.

The first band may include a subcarrier having a subcarrier index of -64 to -1. The second band may include a subcarrier having a subcarrier index of 0 to 63.

The subcarrier indexes of the 13 consecutive subcarriers in the first band may be -38 to -26. The subcarrier indexes of the 13 consecutive subcarriers in the second band may be 26 to 38.

Since the entire band is 40 MHz, the IFFT may be a 128-point IFFT. Coefficients may be inserted into a first subcarrier into which the first to second sequences are inserted in the entire band. 0 may be inserted into the remaining second subcarriers except the first subcarrier in the entire band. Thus, power can be loaded only for the 4 MHz band for transmitting the actual WUR signal.

The specific generation process of the ON signal is as follows.

The first periodic signal generated by inserting the first sequence in 13 consecutive subcarriers in the first band and performing a 128-point IFFT may be a 3.2us long signal having a 1.6us long period. The first on signal may be generated by selecting a 1.6us long signal from the first periodic signal and inserting a first cyclic prefix (CP).

The second periodic signal generated by inserting the second sequence in 13 consecutive subcarriers in the second band and performing a 128-point IFFT may be a 3.2us long signal having a 1.6us long period. The second on signal may be generated by selecting a 1.6us length signal from the second periodic signal and inserting a second CP. The length of the first and second CP is 0.4us.

In a second embodiment, the total band is 80 MHz, the first band is the first 20 MHz of the 80 MHz, the second band is the second 20 MHz of the 80 MHz, and the third band is the third 20 MHz of the 80 MHz Assume that the fourth band is the fourth 20 MHz of the 80 MHz.

In this case, the transmitter may generate a third wakeup packet and a fourth wakeup packet.

The transmitter may transmit the third wakeup packet through a third band and transmit the fourth wakeup packet through a fourth band.

When the total band is 80 MHz, the first band is the first 20 MHz of the 80 MHz, the second band is the second 20 MHz of the 80 MHz, the third band is the third 20 MHz of the 80 MHz, and the fourth The band may be the fourth 20 MHz of the 80 MHz.

A OOK scheme may be applied to the third and fourth wakeup packets, and the third and fourth wakeup packets may have the first data rate or the second data rate.

The third wakeup packet may include a third on signal or a third off signal, and the fourth wakeup packet may include a fourth on signal or a fourth off signal.

The third on signal is generated by inserting a third sequence into 13 consecutive subcarriers in the third band and performing an IFFT, and the fourth on signal is generated into 13 consecutive subcarriers in the fourth band. It can be generated by inserting 4 sequences and performing IFFT.

The length of the third and fourth sequences is seven. As described above, in the present embodiment, HDR may be applied to some of the first to fourth bands, and LDR may be applied to other portions, so that a 2us on signal (or 2us waveform) is formed in terms of implementation, PAPR, and performance. do. That is, the transmitting device may perform a single IFFT to form a 2us on signal that is a basic signal unit.

Therefore, in the present embodiment, it is assumed that LDR is also generated by using a sequence of length 7 as in the case of HDR by configuring an on signal having a 4us length as a 2us on signal + a 2us on signal. Similarly, in the case of LDR, the 4us long off signal may be configured as a 2us off signal + a 2us off signal.

When the full band is 80 MHz, the coefficients of the first sequence may be inserted into subcarriers having subcarrier indices of -102, -100, -98, -96, -94, -92, and -90. Coefficients of the second sequence may be inserted into subcarriers having subcarrier indices of -38, -36, -34, -32, -30, -28, and -26. Coefficients of the third sequence may be inserted into subcarriers having 26, 28, 30, 32, 34, 36, and 38 subcarrier indices. The coefficients of the fourth sequence may be inserted into subcarriers having 90, 92, 94, 96, 98, 100, and 102 subcarrier indices. That is, since the lengths of the first to fourth sequences are seven, it can be seen that they are actually inserted into seven subcarriers. Accordingly, 0 may be inserted into subcarriers in which the coefficients of the first sequence are not inserted in 13 consecutive subcarriers in the first band. In the 13 consecutive subcarriers in the second band, 0 may be inserted in a subcarrier in which the coefficient of the second sequence is not inserted. Zero subcarriers may be inserted in subcarriers in which the coefficients of the third sequence are not inserted in thirteen consecutive subcarriers in the third band. Zero subcarriers may be inserted in subcarriers in which the coefficients of the fourth sequence are not inserted in thirteen consecutive subcarriers in the fourth band.

When transmitting a wake-up packet through a plurality of bands, the entire subbands and subcarrier indexes for each band may be determined as follows.

The first band may include a subcarrier having a subcarrier index of -128 to -65. The second band may include a subcarrier having a subcarrier index of -64 to -1. The third band may include a subcarrier having a subcarrier index of 0 to 63. The fourth band may include a subcarrier having a subcarrier index of 64 to 127.

Subcarrier indices of 13 consecutive subcarriers in the first band may be -102 to -90. Subcarrier indices of 13 consecutive subcarriers in the second band may be -38 to -26. The subcarrier indexes of the 13 consecutive subcarriers in the third band may be 26 to 38. The subcarrier indexes of the 13 consecutive subcarriers in the fourth band may be 64 to 127.

Since the entire band is 80 MHz, the IFFT may be a 256-point IFFT. Coefficients may be inserted into a first subcarrier into which the first to fourth sequences are inserted in the entire band. 0 may be inserted into the remaining second subcarriers except the first subcarrier in the entire band. Thus, power can be loaded only for the 4 MHz band for transmitting the actual WUR signal.

The specific generation process of the ON signal is as follows.

The first periodic signal generated by inserting the first sequence in 13 consecutive subcarriers in the first band and performing a 256-point IFFT may be a 3.2us long signal having a 1.6us long period. The first on signal may be generated by selecting a 1.6us length signal from the first periodic signal and inserting a first CP.

The second periodic signal generated by inserting the second sequence in 13 consecutive subcarriers in the second band and performing a 256-point IFFT may be a 3.2us long signal having a 1.6us long period. The second on signal may be generated by selecting a 1.6us length signal from the second periodic signal and inserting a second CP.

The third periodic signal generated by inserting the third sequence in 13 consecutive subcarriers in the third band and performing a 256-point IFFT may be a 3.2us long signal having a 1.6us long period. The third on signal may be generated by selecting a 1.6us long signal from the third periodic signal and inserting a third CP.

The fourth periodic signal generated by inserting the fourth sequence in 13 consecutive subcarriers in the fourth band and performing a 256-point IFFT may be a 3.2us long signal having a 1.6us long period. The fourth on signal may be generated by selecting a 1.6us long signal from the fourth periodic signal and inserting a fourth CP. The length of the first to fourth CP is 0.4us.

In addition, 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.

According to the exemplary embodiment of the present specification, 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.

In addition, the present embodiment may optimize the WUR FDMA implementation and minimize the PAPR by setting a subcarrier index and a sequence for transmitting the wakeup packet using a plurality of bands.

1 is a conceptual diagram illustrating a structure of a wireless local area network (WLAN).

2 is a diagram illustrating an example of a PPDU used in the IEEE standard.

3 is a diagram illustrating an example of a HE PPDU.

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.

6 shows an example of a wakeup packet structure according to the present embodiment.

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.

9 shows a method of designing a OOK pulse according to the present embodiment.

10 is an explanatory diagram of a Manchester coding scheme according to the present embodiment.

11 illustrates various examples of a symbol repetition technique of repeating n symbols according to the present embodiment.

12 illustrates various examples of a symbol reduction technique according to the present embodiment.

FIG. 13 shows an example of configuring a 2us on signal based on signal masking according to the present embodiment.

14 shows an example of a wakeup packet structure to which different sink parts are applied according to the present embodiment.

15 shows constellations of BPSK modulation.

16 shows the constellation of QPSK modulation.

17 shows the constellation of 16QAM modulation.

18 shows constellations of 64QAM modulation.

19 to 22 show constellations of 256QAM modulation.

23 to 26 show constellations of 1024QAM modulation used in 11ax.

27 shows an example of a structure of a WUR PPDU transmitted through a 40 MHz band according to this embodiment.

28 shows an example of a structure of a WUR PPDU transmitted over an 80 MHz band according to this embodiment.

29 is a flowchart illustrating a procedure of transmitting a wake-up packet by applying the OOK scheme according to the present embodiment.

30 is a flowchart illustrating a procedure of receiving a wakeup packet by applying the OOK method according to the present embodiment.

FIG. 31 illustrates an apparatus for implementing the method as described above.

1 is a conceptual diagram illustrating a structure of a wireless local area network (WLAN).

1 shows the structure of the infrastructure basic service set (BSS) of the Institute of Electrical and Electronic Engineers (IEEE) 802.11.

Referring to the top of FIG. 1, the WLAN system may include one or more infrastructure BSSs 100 and 105 (hereinafter, BSS). The 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.

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. The 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).

In the BSS as shown in the upper part of FIG. 1, 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).

1 is a conceptual diagram illustrating an IBSS.

Referring to the bottom of FIG. 1, 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).

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.

On the other hand, 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.

2 is a diagram illustrating an example of a PPDU used in the IEEE standard.

As shown, various types of PHY protocol data units (PPDUs) have been used in the IEEE a / g / n / ac standard. Specifically, the LTF and STF fields included training signals, the SIG-A and SIG-B included control information for the receiving station, and the 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. However, 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.

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.

As shown, a HE-PPDU for a multiple user (MU) 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 (eg, 40 MHz and 80 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. In this case, the length of the effective symbol interval (or FFT interval) may be 3.2us, the CP length is 0.8us, and 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 802.11ax 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). 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.

Hereinafter, a low-power wake-up receiver (LP-WUR) will be described.

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. In addition, low power wake-up receivers use a narrow bandwidth of less than 5 MHz. In addition, 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.

As shown in Figures 4 and 5, if there is data to be transmitted and 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.

Referring to FIG. 4, the Wi-Fi / BT / BLE 420 is turned off and the low power wake-up receiver 430 is turned on without receiving data. Some studies show that the low power wake-up receiver (LP-WUR) can consume less than 1mW.

However, as shown in FIG. 5, when a wakeup packet is received, 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.

As another example, if 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.

A number of granular wakeup modes have been defined for 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. However, according to the above embodiment, 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.

In addition, in the above embodiment, 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.

In addition, the transmitter 500 may be set to transmit a wakeup packet to the receiver 510. For example, the low power wake-up receiver 530 may be instructed to wake up the main radio 520.

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.

In addition, 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.

Referring to FIG. 6, 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.

In addition, the wakeup packet 600 may include a legacy preamble or any other preamble 610 as defined by the IEEE 802.11 specification. In addition, 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. In addition, by adding 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.

In addition, 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.

In addition, the payload 620 may include a frame body 626 that may include other information of the wakeup packet. For example, the frame body 626 may include length or size information of the payload.

In addition, the payload 620 may include a Frame Check Sequence (FCS) field 628 that includes a Cyclic Redundancy Check (CRC) value. For example, it may include a CRC-8 value or a CRC-16 value of the MAC header 624 and the frame body 626.

7 shows a signal waveform of a wakeup packet according to the present embodiment.

Referring to FIG. 7, 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.

In addition, 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. In contrast, the payload may be modulated according to the OOK method. However, the wakeup preamble 722 in the payload may be modulated according to another modulation scheme.

If the legacy preamble 710 is transmitted on a channel bandwidth of 20 MHz to which 64 FFTs are applied, 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.

First, a modulation scheme using the OOK scheme and a Manchester coding scheme will be described.

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.

Referring to FIG. 8, information in the form of a binary sequence having 1 or 0 as a bit value is represented. By using a bit value of 1 or 0 of the binary sequence information, 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. 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. As the light-emitting diode blinks, the receiver receives and restores data transmitted in the form of visible light, thereby enabling communication using visible light. However, since the blinking of the light emitting diode cannot be perceived by the human eye, the person feels that the illumination is continuously maintained.

For convenience of description, as shown in FIG. 8, information in the form of a binary sequence having 10 bit values is used. Referring to FIG. 8, there is information in the form of a binary sequence having a value of '1001101011'. As described above, when the bit value is 1, the transmitter is turned on, and when the bit value is 0, the transmitter is turned off, the symbol is turned on at 6 bit values out of 10 bit values. ) do. Therefore, when the symbol is turned on in all 10 bit values, if the power consumption is 100%, the power consumption is 60% according to the duty cycle of FIG. 8.

That is, it can be said that the power consumption of the transmitter is determined according to the ratio of 1 and 0 constituting the binary sequence information. In other words, if there is a constraint that the power consumption of the transmitter must be kept at a certain value, the ratio of 1 and 0, which constitutes information in binary sequence form, must also be maintained. For example, in the case of lighting equipment, since the lighting must be maintained at a specific luminance value desired by people, the ratio of 1 and 0 constituting the information in the form of a binary sequence must also be maintained.

However, since the receiver is mainly a wake-up receiver (WUR), the transmission power is not important. 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. Specifically, power consumption of Resonator + Oscillator + PLL (1500uW)-> LPF (300uW)-> ADC (63uW)-> decoding processing (OFDM receiver) (100mW) may occur.

-WUR power consumption is about 1mW. Specifically, power consumption of Resonator + Oscillator (600uW)-> LPF (300uW)-> ADC (20uW)-> decoding processing (Envelope detector) (1uW) may occur.

9 shows a method of designing a OOK pulse according to the present embodiment.

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. However, since the wakeup packet is for low power communication, the OOK method is applied to the ON-signal. The on signal is a signal having an actual power value, and the off signal (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.

In the OOK method, information (bit) 1 may be an on signal and information (bit) 0 may be an off signal. Alternatively, when the Manchester coding scheme is applied, information 1 may indicate a transition from an off signal to an on signal, and information 0 may indicate a transition from an on signal to an off signal. Alternatively, on the contrary, the information 1 may indicate the transition from the on signal to the off signal, and the information 0 may indicate the transition from the off signal to the on signal. Manchester coding scheme will be described later.

Referring to FIG. 9, as shown in the right frequency domain graph 920, the transmitter applies a sequence by selecting 13 consecutive subcarriers of a 20 MHz band as a reference band as a sample. In FIG. 9, 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. In this case, the subcarrier index 0 may be nulled to 0 as the DC subcarrier. Set a specific sequence only to the 13 subcarriers selected as samples, and set all subcarriers except the subcarriers (subcarrier indexes -32 to -7 and subcarrier indexes +7 to +31) to 0. .

In addition, since 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. By moving the power to the center, the signal to noise ratio (SNR) can be increased and the power consumption of the AC / DC converter of the receiver can be reduced. In addition, the power consumption can be reduced by reducing the sampling frequency band to 4.06MHz.

In addition, as shown in the left time domain graph 910 of FIG. 9, 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. On the other hand, the transmitter may not transmit the off signal at all. When performing 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.

However, the basic data rate for one information may be 125 Kbps (8us) or 62.5Kbps (16us).

Generalizing the above, the signal transmitted in the frequency domain is as follows. That is, 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. In this case, the indices of the K subcarriers used by the signal corresponding to the information 0 and the information 1 are the same. For example, the subcarrier index used may be represented as 33-floor (K / 2): 33 + ceil (K / 2) -1.

In this case, the information 1 and the information 0 may have the following values.

Information 0 = zeros (1, K)

Information 1 = alpha * ones (1, K)

The alpha is a power normalization factor and may be, for example, 1 / sqrt (K).

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.

That is, 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.

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.

When 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. Alternatively, 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.

As shown in FIG. 10, the bit string to be transmitted is 10011101, the Manchester coded signal is 0110100101011001, and 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.

By using the Manchester coding scheme, it is possible to communicate in a synchronous manner using only a data transmission channel without using a separate clock.

In addition, 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.

Since STAs requiring robust performance and STAs receiving strong signals from APs are mixed, it is necessary to support efficient data rates in some situations. In order to obtain reliable and robust performance, a symbol coding based symbol coding technique and a symbol repetition technique may be used. In addition, a symbol reduction technique may be used to obtain a high data rate.

In this case, each symbol may be generated using an existing 802.11 OFDM transmitter. In addition, the number of subcarriers used to generate each symbol may be thirteen. However, it is not limited thereto.

In addition, 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.

The following are various examples of symbol types.

For example, 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. Specifically, 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. In this case, a coefficient of 0 may be loaded on the DC subcarrier or the middle subcarrier index among all available subcarriers.

Different sequences may be applied to the available subcarriers according to the 3.2us on signal and the 3.2us off signal. 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.

Accordingly, one bit information corresponding to one basic WUR symbol may be represented as shown in the following table.

Information ‘0’	Information ‘1’
3.2us OFF-signal	3.2us ON-signal

Table 2 does not indicate CP separately. In fact, 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.

As another example, 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.

In the OOK transmission using the Wi-Fi transmitter, the time used for transmitting one bit (or symbol) except for the guard interval of the transmission signal is 3.2 us. In this case, if Manchester coding is applied, 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.

* Information 0-> 1 0 (each can be referred to as sub information 1 0 or sub symbol 1 (ON) 0 (OFF))

First 1.6us (sub information 1 or sub symbol 1): 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)).

In addition, 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. For example, suppose that 13 subcarriers are used to construct an on-signal, 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. At this time, a, b, c, d, e, f, g is 1 or -1.

That is, 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. In this way, 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.

Second 1.6us (sub information 0 or sub symbol 0): The sub information 0 may have a value of zeros (1, K). Similarly, 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-> 0 1 (each can be referred to as sub information '0', '1' or sub symbol 0 (OFF) 1 (ON))

Since 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.

By using a technique of generating information 0 and information 1 using Manchester coding, it is possible to prevent the off symbol from continuing as compared to the conventional method. Therefore, a coexistence problem with an existing Wi-Fi device may not occur. 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.

According to the above description, 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.

Accordingly, one bit information corresponding to one Manchester coded symbol may be represented as shown in the following table.

Information ‘0’	Information ‘1’
1.6us ON-signal + 1.6us OFF-signal	1.6us OFF-signal + 1.6us ON-signal
Or 1.6us OFF-signal + 1.6us ON-signal	Or 1.6us ON-signal + 1.6us OFF-signal

Table 3 does not indicate CP separately. In fact, 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.

As another example, a method of constructing a wake-up packet by repeating symbols for performance improvement is proposed.

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. Thus, the length (time) of the wakeup payload 724 is doubled.

That is, it is proposed to apply a symbol representing information such as information 0 or information 1 to a specific sequence and to repeat the configuration as follows.

Option 1: Information 0 and Information 1 can be repeatedly represented by the same symbol.

Info 0-> 0 0 (repeat Info 0 twice)

-Info 1-> 1 1 (repeat Info 1 twice)

Option 2: Information 0 and Information 1 can be repeatedly represented by different symbols.

Information 0-> 0 1 or 1 0 (repeat info 0 and info 1)

Info 1-> 1 0 or 0 1 (repeat Info 1 and Info 0)

Hereinafter, a method of decoding by a receiving apparatus a signal transmitted by applying a symbol repetition technique to the transmitting apparatus will be described.

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. In non-coherent detection, the phase relationship between the transmitter and receiver signals is not fixed. Thus, the receiver does not need to measure and adjust the phase of the received signal. In contrast, 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. In the option 1, 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.

In detail, 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.

In addition, in option 2, information may be determined by comparing the power of two symbols without determining a threshold.

Specifically, if information 1 is composed of 0 1 and information 0 is composed of 1 0, it is determined as information 0 if the power of the first symbol is greater than the power of the second symbol. On the contrary, if the power of the first symbol is less than the power of the second symbol, it is determined as information 1.

This is because the order of symbols can be reconstructed by an interleaver. The interleaver may be applied in units of specific symbol numbers below the packet unit.

In addition, not only two symbols but also 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-> 0 0 ... 0 (repeat info 0 n times)

-Information 1-> 1 1 ... 1 (repeat information 1 n times)

* Option 2: As shown in FIG. 11, information 0 and information 1 may be repeatedly represented by different symbols n times.

-Information 0-> 0 1 0 1 ... or 1 0 1 0 ... (repeat info 0 and info 1 n times with each other)

-Info 1-> 1 0 1 0 ... or 0 1 0 1 ... (repeat info 1 and info 0 n times with each other)

Option 3: As shown in FIG. 11, 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.

-Information 0-> 0 0 ... 1 1 ... or 1 1 ... 0 0 ... (n / 2 symbols consist of information 0, the remaining n / 2 symbols consist of information 1 do)

-Information 1-> 1 1 ... 0 0 ... or 0 0 ... 1 1 ... (n / 2 symbols consist of information 0, the remaining n / 2 symbols consist of information 1 do)

Option 4: When n is odd, as shown in FIG. 11, the total number of symbols may be represented by dividing the number of symbols 1 (symbol including information 1) and the number of symbols 0 (symbol including information 0).

Information 0-> n symbols where the number of symbols 1 is odd and the number of symbols 0 is even, or n symbols where the number of symbols 1 is even and the number of symbols 0 is odd

Information 1-> n symbols where the number of symbols 0 is odd and the number of symbols 1 is even, or n symbols where the number of symbols 0 is even and the number of symbols 1 is odd

In addition, the order of symbols may be reconstructed by the interleaver. The interleaver may be applied in units of packets and specific symbols.

In addition, as described above, 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.

However, the use of consecutive symbol 0 (or off symbol) 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. Thus, the option 2 scheme may be preferred as it is desirable to avoid the use of consecutive off symbols to solve the leveling problem.

In addition, it can be extended in a manner of expressing m information using n symbols. In this case, 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.

For example, if a code rate of 3/4 is applied to the information 010, it may be 1,010 or 010,1 or 0,010 or 010,0. However, in order to prevent the use of consecutive off symbols, it may be desirable to apply a code rate of 1/2 or less.

In this embodiment as well, the order of symbols can be reconstructed by the interleaver. The interleaver may be applied in units of packets and specific symbols.

Hereinafter, various embodiments of a symbol to which the symbol repetition technique is applied will be described.

In general, a symbol to which the symbol repetition technique is applied may be represented by n (CP + 3.2us) or CP + n (1.6us).

As shown in FIG. 11, n (n> = 2) information signals (symbols) are used to represent 1 bit, and a specific sequence is applied to all available subcarriers (for example, 13). Form a signal (symbol).

Different sequences may be applied to the available subcarriers according to the 3.2us on signal and the 3.2us off signal. 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.

Accordingly, 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.

Information ‘0’	Information ‘1’
3.2us OFF-signal	3.2us ON-signal
Or two specific consecutive signals are 3.2us ON-signal + 3.2us OFF-signal, all other signals are ON or all OFF	Or two specific consecutive signals are 3.2us OFF-signal + 3.2us ON-signal, all other signals are ON or all OFF
Or two specific consecutive signals are 3.2us OFF-signal + 3.2us ON-signal, all other signals are ON or all OFF	Or two specific consecutive signals are 3.2us ON-signal + 3.2us OFF-signal, all other signals are ON or all OFF
Or a certain number (or ceil (n / 2) or floor (n / 2)) placed in a specific position is 3.2us OFF-signal, 3.2us ON-signalEx) ON + OFF + ON + OFF…	Or a certain number (or ceil (n / 2) or floor (n / 2)) placed in a specific position is 3.2us ON-signal, 3.2us OFF-signalEx) OFF + ON + OFF + ON + OFF…

Table 4 does not indicate CP separately. In fact, 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.

As another example, 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.

According to the above embodiment, two information signals (symbols) 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. Form.

Different sequences may be applied to the available subcarriers according to the 3.2us on signal and the 3.2us off signal. 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.

Accordingly, one bit information corresponding to a symbol to which the symbol repetition technique is applied may be represented as shown in the following table.

Information ‘0’	Information ‘1’
3.2us OFF-signal	3.2us ON-signal + 3.2us ON-signal
Or 3.2us ON-signal + 3.2us OFF-signal	Or 3.2us OFF-signal + 3.2us ON-signal
Or 3.2us OFF-signal + 3.2us ON-signal	Or 3.2us ON-signal + 3.2us OFF-signal

Table 5 does not indicate CP separately. Indeed, 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. .

As another example, 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.

According to the above embodiment, three information signals (symbols) 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. Form.

Different sequences may be applied to the available subcarriers according to the 3.2us on signal and the 3.2us off signal. 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.

Accordingly, one bit information corresponding to a symbol to which the symbol repetition technique is applied may be represented as shown in the following table.

Information ‘0’	Information ‘1’
3.2us OFF-signal + 3.2us OFF-signal + 3.2us OFF-signal	3.2us ON-signal + 3.2us ON-signal + 3.2us ON-signal
Or 3.2us ON-signal + 3.2us ON-signal + 3.2us OFF-signal	Or 3.2us ON-signal + 3.2us OFF-signal + 3.2us ON-signal
Or 3.2us ON-signal + 3.2us OFF-signal + 3.2us ON-signal	Or 3.2us ON-signal + 3.2us ON-signal + 3.2us OFF-signal
Or 3.2us ON-signal + 3.2us OFF-signal + 3.2us ON-signal	Or 3.2us OFF-signal + 3.2us ON-signal + 3.2us OFF-signal

Table 6 does not indicate CP separately. In fact, 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, 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.

As another example, 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.

According to the above embodiment, four information signals (symbols) 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. Form.

Different sequences may be applied to the available subcarriers according to the 3.2us on signal and the 3.2us off signal. 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.

Accordingly, one bit information corresponding to a symbol to which the symbol repetition technique is applied may be represented as shown in the following table.

Information ‘0’	Information ‘1’
3.2us OFF-signal + 3.2us OFF-signal + 3.2us OFF-signal + 3.2us OFF-signal	3.2us ON-signal + 3.2us ON-signal + 3.2us ON-signal + 3.2us ON-signal
Or 3.2us ON-signal + 3.2us ON-signal + 3.2us ON-signal + 3.2us OFF-signal	Or 3.2us ON-signal + 3.2us ON-signal + 3.2us OFF-signal + 3.2us ON-signal
Or 3.2us ON-signal + 3.2us ON-signal + 3.2us OFF-signal + 3.2us ON-signal	Or 3.2us ON-signal + 3.2us ON-signal + 3.2us ON-signal + 3.2us OFF-signal
Or 3.2us ON-signal + 3.2us ON-signal + 3.2us OFF-signal + 3.2us ON-signal	Or 3.2us ON-signal + 3.2us OFF-signal + 3.2us ON-signal + 3.2us ON-signal
Or 3.2us ON-signal + 3.2us OFF-signal + 3.2us ON-signal + 3.2us ON-signal	Or 3.2us ON-signal + 3.2us ON-signal + 3.2us OFF-signal + 3.2us ON-signal
Or 3.2us ON-signal + 3.2us OFF-signal + 3.2us ON-signal + 3.2us OFF-signal	Or 3.2us OFF-signal + 3.2us ON-signal + 3.2us OFF-signal + 3.2us ON-signal
Or 3.2us ON-signal + 3.2us ON-signal + 3.2us OFF-signal + 3.2us OFF-signal	Or 3.2us OFF-signal + 3.2us OFF-signal + 3.2us ON-signal + 3.2us ON-signal
Or 3.2us OFF-signal + 3.2us OFF-signal + 3.2us ON-signal + 3.2us ON-signal	Or 3.2us ON-signal + 3.2us ON-signal + 3.2us OFF-signal + 3.2us OFF-signal

Table 7 does not indicate CP separately. Indeed, 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, 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.

As another example, 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).

According to the above embodiment, a symbol is repeated using a symbol repeated n (> = 2) times, and a specific sequence is applied to all available subcarriers (for example, 13), and the remaining coefficients of 0 are applied. By setting 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.

Accordingly, 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.

Information ‘0’	Information ‘1’
(1.6us ON-signal + 1.6us OFF-signal) Repeat n times	(1.6us OFF-signal + 1.6us ON-signal) Repeat n times
Or (1.6us OFF-signal + 1.6us ON-signal) n times	Or (1.6us ON-signal + 1.6us OFF-signal) n times
(1.6us ON-signal + 1.6us OFF-signal) + (1.6us OFF-signal + 1.6us ON-signal) floor (n / 2) Repeat + if necessary (1.6us ON-signal + 1.6us OFF-signal)	(1.6us OFF-signal + 1.6us ON-signal) + (1.6us ON-signal + 1.6us OFF-signal) floor (n / 2) Repeat + if necessary (1.6us OFF-signal + 1.6us ON-signal)
(1.6us OFF-signal + 1.6us ON-signal) + (1.6us ON-signal + 1.6us OFF-signal) floor (n / 2) Repeat + if necessary (1.6us OFF-signal + 1.6us ON-signal)	(1.6us ON-signal + 1.6us OFF-signal) + (1.6us OFF-signal + 1.6us ON-signal) floor (n / 2) Repeat + if necessary (1.6us ON-signal + 1.6us OFF-signal)

Table 8 does not indicate CP separately. In fact, 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.

Like the embodiments described above, the symbol repetition technique can satisfy the range requirement of low power wake-up communication. When only the OOK method is applied, the data rate for one symbol is 250 Kbps (4us). At this time, if the symbol is repeated twice using the symbol repetition technique, the data rate may be 125 Kbps (8us), and if the fourth repetition is performed, the data rate may be 62.5 Kbps (16us), and if the eight times are repeated, the data rate may be 31.25Kbps (32us). have. In the case of low-power wake-up communication, if there is no BCC, the symbol needs to be repeated eight times to satisfy the range requirement.

Hereinafter, various embodiments of a symbol to which a symbol reduction technique is applied among symbol types that can be used in the WUR will be described.

12 illustrates various examples of a symbol reduction technique according to the present embodiment.

According to the embodiment of FIG. 12, as the m value increases, the symbol is further reduced to reduce the length of a symbol carrying one piece of information. When m = 2, the length of a symbol carrying one piece of information becomes CP + 1.6us. When m = 4, the length of a symbol carrying one piece of information becomes CP + 0.8us. When m = 8, the length of a symbol carrying one piece of information becomes CP + 0.4us.

As the length of the symbol decreases, a high data rate can be ensured. If only the OOK scheme is applied, the data rate for one symbol is 250 Kbps (4us). In this case, using m = 2, the data rate is 500 Kbps (2us), if m = 4, the data rate is 1Mbps (1us), if m = 8 data rate can be 2Mbps (0.5us). .

For example, a symbol to which a symbol reduction technique is generally applied may be represented by CP + 3.2us / m (m = 2,4,8,16,32, ...) (option 1).

As shown in option 1 of FIG. 12, 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. Subsequently, if IFFT is applied to the subcarrier to which the specific sequence is applied, a 3.2us signal having a 3.2us / m period is generated. Take one of these and map it to the 3.2us / m information signal (information 1).

For example, if a specific sequence is applied in units of two columns (m = 2) to 13 subcarriers, the on signal may be configured as follows.

On signal (information 1): {a 0 b 0 c 0 d 0 e 0 f 0 g} or {0 a 0 b 0 c 0 d 0 e 0 f 0}, where a, b, c, d, e, f, g is 1 or -1.

As another example, if a specific sequence is applied to 13 subcarriers in units of four squares (m = 4), the on signal may be configured as follows.

On signal (Info 1): {a 0 0 0 b 0 0 0 c 0 0 0 d} or {0 a 0 0 0 b 0 0 0 c 0 0 0} or {0 0 a 0 0 0 b 0 0 0 c 0 0} or {0 0 0 a 0 0 0 b 0 0 0 c 0} or {0 0 a 0 0 0 0 0 0 0 b 0 0}, where a, b, c, d is 1 or -1.

As another example, if a specific sequence is applied to 13 subcarriers by 8 columns (m = 8), the on signal may be configured as follows.

On signal (information 1): {a 0 0 0 0 0 0 0 b 0 0 0 0} or {0 a 0 0 0 0 0 0 0 b 0 0 0} or {0 0 a 0 0 0 0 0 0 0 0 b 0 0} or {0 0 0 a 0 0 0 0 0 0 0 b 0}, or {0 0 0 0 a 0 0 0 0 0 0 0 b}, where a and b are 1 or -1 .

The 3.2us / m information signal is divided into a 3.2us / m on signal and a 3.2us / m off signal. In addition, 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.

CP can be used by adopting a specific length from the back of the information signal 3.2us / m immediately behind. At this time, CP may be 0.4us or 0.8us. This length is equal to the guard interval of 802.11ac. However, when m = 8, the CP cannot be 0.8us. Alternatively, CP may be 0.1us or 0.2us, or another value.

Accordingly, 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.

Information ‘0’	Information ‘1’
3.2us / m OFF-signal	3.2us / m ON-signal

CP is not shown separately in Table 9. In fact, 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.

As another example, a symbol to which the symbol reduction technique is applied may be represented by CP + 3.2us / m + CP + 3.2us / m (m = 2,4,8) (option 2).

In the OOK transmission using the Wi-Fi transmitter, the time used for transmitting one bit (or symbol) except for the guard interval of the transmission signal is 3.2 us. At this time, if the symbol reduction technique is applied, the time used for one bit transmission is 3.2us / m. However, in this embodiment, 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.

* Information 0-> 1 0 (each can be referred to as sub information 1 0 or sub symbol 1 (ON) 0 (OFF))

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.

* Information 1-> 0 1 (each can be referred to as sub information '0', '1' or sub symbol 0 (OFF) 1 (ON))

-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.

In addition, information 0 may be configured as 01 and information 1 may be configured as 10.

As in option 2 of FIG. 12, 1-bit information corresponding to a symbol to which a symbol reduction technique is applied may be represented as shown in the following table.

Information ‘0’	Information ‘1’
3.2us / m OFF-signal + 3.2us / m ON-signal or 3.2us / m ON-signal + 3.2us / m OFF-signal	3.2us / m ON-signal + 3.2us / m OFF-signal or 3.2us / m OFF-signal + 3.2us / m ON-signal

In Table 10, CP is not separately indicated. In fact, 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.

	Information ‘0’	Information ‘1’
Option 1 (m = 2,4,8)	2us OFF-signal	2us ON-signal
	1us OFF-signal	1us ON-signal
	0.5us OFF-signal	0.5us ON-signal
Option 2 (m = 4,8)	1us OFF-signal + 1us ON-signal or 1us ON-signal + 1us OFF-signal	1us ON-signal + 1us OFF-signal or 1us OFF-signal + 1us ON-signal
	0.5us OFF-signal + 0.5us ON-signal or 0.5us ON-signal + 0.5us OFF-signal	0.5us ON-signal + 0.5us OFF-signal or 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.

For example, when m = 4 in Option 2, 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. In Option 2, since Manchester coding is applied and symbols are repeated, the data rate of one information can be 500 Kbps when m = 4.

As another example, when m = 8 in Option 2, 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. In Option 2, since Manchester coding is applied and symbols are repeated, the data rate of one information may be 1Mbps when m = 8.

In the table below, the data rates that can be secured through the above-described embodiments are compared with each other.

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

CP	Symbol rep.n (CP + 3.2us)			CP rep.CP + n (3.2us)			Man. symbol rep.n (CP + 1.6us + CP + 1.6us)
	n = 2 (Example 4)	n = 3 (Example 5)	n = 4 (Example 6)	n = 2 (Example 7)	n = 3 (Example 8)	n = 4 (Example 9)	n = 2 (Example 10)	n = 3 (Example 11)	n = 4 (Example 12)
0.4us	138.9	92.6	69.4	147.1	100.0	75.8	125.0	83.3	62.5
0.8us	125.0	83.3	62.5	138.9	96.2	73.5	104.2	69.4	52.1

CP	Man. CP + n symbols (1.6us + 1.6us)			Symbol reductionCP + 3.2us / m
	n = 2 (Example 13)	n = 3 (Example 14)	n = 4 (Example 15)	m = 2 (Example 16)	m = 4 (Example 17)	m = 8 (Example 18)
0.4us	147.1	100.0	75.8	500.0	833.3	1250.0
0.8us	138.9	96.2	73.5	416.7	625.0	NA

CP	Symbol reductionCP + 3.2us / m		Man. symbol rep. w / Man.CP + 3.2us / m + CP + 3.2us / m
	m = 4	m = 8	m = 4	m = 8
0.1us	1111.1	2000	555.6	1000
0.2us	1000	1666.7	500	833.3

FIG. 13 shows an example of configuring a 2us on signal based on signal masking according to the present embodiment.

Data rates can be ensured according to the various symbol types that can be used in the WUR. In this case, 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 (all coefficients are inserted into 13 consecutive subcarriers in the 20 MHz band).

Referring to FIG. 13, in the case of a masking-based approach, first, a 4us OOK symbol may be generated. A 64-point IFFT is applied to 13 consecutive subcarriers of 20 MHz band to perform a 64-point IFFT, and a 4us OOK symbol is generated by adding 0.8us CP or GI. The 2us on signal may be configured by masking half of the 4us OOK symbol.

For example, referring to FIG. 13, the information 0 may take the first half of the 4us symbol to configure the 2us on signal. The latter half of the 4us symbol does not transmit any information and thus can constitute a 2us off signal. In addition, information 1 may take a half part of the symbol to form a 2us false signal. The front half of the 4us symbol can configure a 2us off signal by not transmitting any information.

In addition, in the following, various data rates may be applied to the payload of the WUR PPDU in an 802.11ba system, and two types of sync parts or sync fields having different lengths may be used to reduce the overhead of the WUR PPDU. WUR PPDU can be configured. In this specification, various schemes for indicating a data rate applied to a payload using two types of sink parts or sink fields are proposed.

14 shows an example of a wakeup packet structure to which different sink parts are applied according to the present embodiment.

14 is an example of a WUR PPDU to which sink parts (or sink fields) having two types of different lengths and sequences are respectively applied in the IEEE 802.11ba system. Sync 1 and Sync 2 are each formed of a sequence of 1 and 0 (or -1) with the same number and can be designed to have good auto-correlation properties. The cross-correlation value is designed to have a small value so that the receiver can easily identify which sync is applied to the PPDU. (The receiver performs simultaneous cross-correlation of the received signal using the sequence of sync 1 and 2.) Therefore, it can be used to indicate two data rates without additional PHY signaling. For example, sync 1 can be used for WUR PPDUs with a 62.5kbps data rate applied to the payload using long sequences and symbols. In addition, relatively short sequences and symbols can be used for WUR PPDUs with data rates of 250kbps on the payload.

14 shows a PPDU used in an IEEE 802.11ba system, and two data rates of 62.5 kbps and 250 kbps are used in a data field, and information on each data rate is shown in Table 16 below.

	62.5 kbps	250 kbps
Information 0	4us on + 4us off + 4us on + 4us off	2us on + 2us off
Information 1	4us off + 4us on + 4us off + 4us on	2us off + 2us on

In the present specification, the AP may configure a WUR PPDU for multi-user / multi-group transmission using the center 4MHz band of each 20MHz band when the AP transmits the WUR packet using the bandwidth of 40MHz / 80MHz in the IEEE 802.11ba system. In this context, the present specification proposes a OOK waveform generation method.

In 11ba, data rates of 62.5kbps and 250kbps are used and have the following symbol structure.

Input bit	MC-OOK modulated symbol
0	[SymLDROn, SymLDROff, SymLDROn, SymLDROff]
One	[SymLDROff, SymLDROn, SymLDROff, SymLDROn]

Input bit	MC-OOK modulated symbol
0	[SymHDROn, SymHDROff]
One	[SymHDROff, SymHDROn]

In Table 17, LDR (WUR-LDR) indicates a WUR low data rate and means 62.5 kbps. In Table 18, HDR (WUR-HDR) indicates a WUR high data rate and 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 the WUR uses a signal bandwidth of about 4 MHz, 13 of the 64 subcarriers are used. That is, a 13-length sequence is applied to 13 subcarriers and 0 is substituted for the remaining 51 subcarriers, and then 4us on-signal can be generated by applying appropriate power scaling, 64 point IFFT, and 0.8us cyclic prefix. Here, 13 subcarrier indexes may be -6 to 6, and a coefficient of 0 may be inserted into subcarrier index 0.

Alternatively, the transmitter can apply 7 length sequences (1,3,5,7,9,11,13) to 13 subcarriers in units of two spaces, and put the coefficients of 0 in the rest, then apply appropriate power scaling and 64 point IFFT. A 3.2us signal with a period of 1.6us can be created, and the 2nd on-signal can be generated by applying 0.4us cyclic prefix after selecting the first or last 1.6us signal. Here, 13 subcarrier indexes can be -6 to 6, so the actual coefficients are inserted into subcarrier indexes of -6, -4, -2, 0, 2, 4, and 6, and zero coefficients are inserted into subcarrier indexes of 0. Can be.

Considering 4x numerology of 11ax, the center of -26 ~ 25 or -25 ~ 26 subcarrier index of 20MHz -128 ~ 127 subcarrier index can be used for 4MHz WUR transmission, and the 4us symbol is -24, -20, -16, Coefficients can be loaded in 13 subcarrier indexes of -12, -8, -4, 0, 4, 8, 12, 16, 20, and 24 (4 column units), and a 0 coefficient can be inserted in a 0 subcarrier index. have. Then, if 256 IFFT is taken, a 12.8us signal with a 3.2us period is formed, and after selecting the first, second, third, or last 3.2us signals, 4us on-signal can be generated by applying 0.8us cyclic prefix. have.

Also, considering the 4x numerology of 11ax, 2us on-signal generation using 20MHz bandwidth is as follows. Coefficients can be loaded in seven subcarrier indexes of -24, -16, -8, 0, 8, 16, and 24 (8-column units), and zero coefficients can be inserted in zero subcarrier indexes. 256 IFFT is then taken to form a 12.8us signal with a 1.6us period of which 0.4us cyclic after selecting the first or second or third or fourth or fifth or sixth or seventh or last 1.6us signals. 2us on-signal can be generated by applying prefix.

The above-described coefficients inserted at 4 MHz, that is, 13 length and 7 length sequences are constellation points of Binary Phase Shift Keying (BPSK), Quadrature Phase Shift Keying (QPSK), Quadrature Amplitude Modulation (QQK), 64QAM, and 256QAM. It can also be configured as 1024 constellation point of 11ax. The center coefficient value of each 7/13 length sequence may be 0. 15 to 22 are constellation points used at 11ac.

15 shows constellations of BPSK modulation.

16 shows the constellation of QPSK modulation.

17 shows the constellation of 16QAM modulation.

18 shows constellations of 64QAM modulation.

19 to 22 show constellations of 256QAM modulation. 19 shows a first quadrant of the 256QAM constellation. 20 shows a second quadrant of the 256QAM constellation. 21 shows a third quadrant of the 256QAM constellation. 22 shows the fourth quadrant of the 256QAM constellation.

The values of the normalization factor K _MOD according to the modulation scheme of FIGS. 15 to 22 are as follows.

Modulation	K MOD
BPSK	One
QPSK	1 / √2
16QAM	1 / √10
64QAM	1 / √42
256QAM	1 / √170

In the above table, K _MOD represents a value such that the average power of the entire constellation point becomes 1. FIGS. 23 to 26 show constellations of 1024QAM modulation used in 11ax. 23 shows the first quadrant of the 1024QAM constellation. 24 shows the second quadrant of the 1024QAM constellation. 25 shows the third quadrant of the 1024QAM constellation. 26 shows the fourth quadrant of the 1024QAM constellation. The value of the normalization factor K _MOD according to the modulation schemes of FIGS. 23 to 26 is 1 / √682.

WUR PPDU can use band width of 40 / 80MHz as well as 20MHz bandwidth, and WUR PPDU for multi-user can be formed by using multi-band as below.

A. Multi-band transmission

One) 40 MHz

27 shows an example of a structure of a WUR PPDU transmitted through a 40 MHz band according to this embodiment.

Referring to FIG. 27, a subcarrier index of -38 to -26 and a second 20 MHz (0 to 0) corresponding to a center 4 MHz of the first 20 MHz (-64 to -1) among -64 to 63 subcarrier indexes corresponding to the entire 40 MHz band WUR PPDU can be configured using 26 ~ 38 subcarrier index corresponding to center 4MHz of 63), and can be transmitted to 2 users or 2 groups using each band (20MHz each).

Alternatively, when 11ax numerology is used, a subcarrier index of -154 to -103 or -153 to -102 corresponding to a center 4 MHz of the first 20 MHz (-256 to -1) of -256 to 255 subcarrier indexes corresponding to the entire 40 MHz band WUR PPDU can be configured by using subcarrier index of 102 ~ 153 or 103 ~ 154 corresponding to center 4MHz of 20MHz (0 ~ 255) and 2 users or 2 by using each band (20MHz each). Can send to groups

2) 80 MHz

28 shows an example of a structure of a WUR PPDU transmitted over an 80 MHz band according to this embodiment.

Referring to FIG. 28, a subcarrier index of -102 to -90 and a second 20 MHz (-64) corresponding to a center 4 MHz of the first 20 MHz (-128 to -65) among -128 to 127 subcarrier indexes corresponding to the entire 80 MHz band Subcarrier index of -38 ~ -26 corresponding to center 4MHz of ~ -1), subcarrier index of 26 ~ 38 corresponding to center 4MHz of third 20MHz (0 ~ 63), center of fourth 20MHz (64 ~ 127) WUR PPDU can be configured by using 90 ~ 102 subcarrier index corresponding to 4MHz, and can be transmitted to 4 users or 4 groups by using each band (20MHz each).

Alternatively, if 11ax numerology is used, the subcarrier index of -410 ~ -359 or -409 ~ -358 corresponding to the center 4MHz of the first 20MHz (-512 ~ -257) among the -512 ~ 511 subcarrier indexes corresponding to the entire 80MHz band Subcarrier index of -154 ~ -103 or -153 ~ -102, corresponding to center 4MHz of the second 20MHz (-256 ~ -1), 102 ~ 153 or 103, corresponding to center 4MHz of the third 20MHz (0 ~ 255) WUR PPDU can be configured using subcarrier index of ~ 154, 358 ~ 409 or 359 ~ 410 subcarrier index, which corresponds to the center 4MHz of the fourth 20MHz (256 ~ 511), and each band (20MHz each) You can send to 4 users or 4 groups.

In FIG. 27 and FIG. 28, the wake-up signal includes a WUR Sync part and a WUR Data part. First, a waveform generation method in the WUR Data part is proposed and then a waveform generation method of the WUR Sync part is used. Suggest.

B. OOK  waveform generation for the WUR  Data part

The OOK waveform generation in the WUR data part is divided into the general case consisting of a mixture of low and high data rates when all are configured at high data rates and all are configured at low data rates.

One) All sub-bands are configured at high data rates

This is the case of multi-band transmission by allocating only STA or group that can transmit at high data rate. In this case, 2us on-signal and 2us off-signal are required for 4MHz band within each 20MHz, and can be configured as follows.

A) Use 13 length sequence

A 13 length sequence is allocated to a band corresponding to an on signal among 4MHz bands within 20MHz of 40MHz and 80MHz, and the allocation method is as follows for each bandwidth.

<40 MHz>

If the user or group allocated to the first 20 MHz center 4 MHz band of 40 MHz is on-signal, a 13 length sequence is allocated to a subcarrier index of -38 to -26.

If the user or group allocated to the second 20MHz center 4MHz band of 40MHz is on-signal, a 13 length sequence is assigned to the subcarrier index of 26 ~ 38.

<80 MHz

If the user or group assigned to the central 4MHz band of the first 20MHz of 80MHz is on-signal, 13 length sequence is allocated to subcarrier index of -102 ~ -90.

If the user or group allocated to the second 20MHz center 4MHz band of 80MHz is on-signal, 13 length sequence is assigned to subcarrier index of -38 ~ -26.

If the user or group allocated to the third 20MHz center 4MHz band of 80MHz is on-signal, 13 length sequence is allocated to the subcarrier index of 26 ~ 38.

If the user or group allocated to the fourth 20MHz center 4MHz band of 80MHz is on-signal, 13 length sequence is allocated to 90 ~ 102 subcarrier index.

If the sequence is assigned only to the 4MHz band corresponding to the on-signal as above and all the coefficients of 0 are allocated to the remaining subcarriers, and the 40MHz bandwidth is used, a 3.2us signal is applied by applying a 128 point IFFT. In case of using 80MHz bandwidth, 3.2us signal is made by applying 256 point IFFT. You can select a specific 2us signal with good PAPR from 3.2us signals or insert a 0.8us CP to create a 4us signal, and select a specific 2us signal with good PAPR, or select the first or last 2us signals to form a 2us OOK waveform. have.

In case of using 11ax numerology (4x), assign as below and form waveform.

<40 MHz>

-152, -148, -144, -140, -136, -132, -128, -124, -120, -116 if the user or group assigned to the first 4 MHz band of 40 MHz is on-signal A 13 length sequence is assigned to subcarrier indexes of -112, -108, and -104.

If the user or group assigned to the second 20 MHz central 4 MHz band of 40 MHz is on-signal, the subcarrier index of 104, 108, 112, 116, 120, 124, 128, 132, 136, 140, 144, 148, 152 Allocate a length sequence.

<80 MHz

-408, -404, -400, -396, -392, -388, -384, -380, -376, -372 if the user or group assigned to the first 20MHz central 4MHz band of 80MHz is on-signal. A 13 length sequence is assigned to subcarrier indexes of -368, -364, and -360.

-152, -148, -144, -140, -136, -132, -128, -124, -120, -116 if the user or group assigned to the second 20MHz central 4MHz band of 80MHz is on-signal A 13 length sequence is assigned to subcarrier indexes of -112, -108, and -104.

If the user or group assigned to the third 20 MHz central 4 MHz band of 80 MHz is on-signal, the subcarrier index of 104, 108, 112, 116, 120, 124, 128, 132, 136, 140, 144, 148, 152 Allocate a length sequence.

If the user or group assigned to the fourth 20 MHz central 4 MHz band of 80 MHz is on-signal, then the subcarrier index of 360, 364, 368, 372, 376, 380, 384, 388, 392, 396, 400, 404, 408 Allocate a length sequence.

If the sequence is allocated only to the 4MHz band corresponding to the on-signal and the 0 coefficient is allocated to the remaining subcarriers, and the 40MHz bandwidth is used, a 12.8us signal having a 3.2us period is applied by applying a 512 point IFFT. In case of using 80MHz bandwidth, 1024 point IFFT is applied to make 12.8us signal with 3.2us period. Select a specific 2us signal with good PAPR from 12.8us signals, or select one of the first, second, third or fourth 3.2us signals and select a specific 2us signal with good PAPR from 3.2us signals A 4us signal can be inserted by inserting 0.8us CP, and a specific 2us signal with good PAPR can be selected, or a 2us OOK waveform can be formed by selecting a first or last 2us signal.

B) Use 7 length sequence

A 7 length sequence is allocated to a band corresponding to on of 4MHz bands within each 20MHz of 40MHz and 80MHz, and the allocation method is as follows for each bandwidth.

<40 MHz>

If the user or group allocated to the first 20 MHz center 4 MHz band of 40 MHz is on-signal, assign a 7 length sequence to the subcarrier index of -38, -36, -34, -32, -30, -28, or -26. .

If the user or group allocated to the second 20MHz center 4MHz band of 40MHz is on-signal, assign 7 length sequence to subcarrier index of 26, 28, 30, 32, 34, 36, 38.

<80 MHz

If the user or group allocated to the first 20 MHz central 4 MHz band of 80 MHz is on-signal, assign a 7 length sequence to the subcarrier index of -102, -100, -98, -96, -94, -92, or -90. .

If the user or group allocated to the second 20MHz central 4MHz band of 80MHz is on-signal, assign 7 length sequence to subcarrier index of -38, -36, -34, -32, -30, -28, -26. .

If the user or group allocated to the third 20MHz center 4MHz band of 80MHz is on-signal, assign 7 length sequence to subcarrier index of 26, 28, 30, 32, 34, 36, 38.

If the user or group allocated to the fourth 20MHz center 4MHz band of 80MHz is on-signal, assign 7 length sequence to subcarrier index of 90, 92, 94, 96, 98, 100, 102.

As shown above, when the sequence is allocated only to the 4MHz band corresponding to the on-signal and all 0 coefficients are allocated to the remaining subcarriers, when the 40MHz bandwidth is used, a 3.2us signal having a 1.6us period is applied by applying a 128 point IFFT. In case of using 80MHz bandwidth, 3.2us signal with 1.6us period is made by applying 256 point IFFT. A 2us OOK waveform can be formed by selecting the first or last 1.6us signal among 3.2us signals and inserting 0.4us CP.

In case of using 11ax numerology (4x), assign as below and form waveform.

<40 MHz>

If the user or group assigned to the center 4MHz band of the first 20MHz of 40MHz is on-signal, assign 7 length sequences to subcarrier indexes of -152, -144, -136, -128, -120, -112, and -104.

If the user or group allocated to the second 20 MHz center 4 MHz band of 40 MHz is on-signal, a 7 length sequence is allocated to subcarrier indexes of 104, 112, 120, 128, 136, 144, and 152.

<80 MHz

If the user or group assigned to the central 4MHz band of the first 20MHz of 80MHz is on-signal, assign 7 length sequence to subcarrier index of -408, -400, -392, -384, -376, -368, and -360.

If the user or group assigned to the second 20MHz central 4MHz band of 80MHz is on-signal, assign 7 length sequence to subcarrier index of -152, -144, -136, -128, -120, -112, -104. .

If the user or group allocated to the third 20MHz center 4MHz band of 80MHz is on-signal, assign 7 length sequence to subcarrier index of 104, 112, 120, 128, 136, 144, 152.

If the user or group assigned to the fourth 20MHz center 4MHz band of 80MHz is on-signal, assign 7 length sequence to subcarrier index of 360, 368, 376, 384, 392, 400, 408.

If the sequence is assigned only to the 4MHz band corresponding to the on-signal as above and all the coefficients of 0 are allocated to the remaining subcarriers, and the 40MHz bandwidth is used, a 12.8us signal having a 1.6us period is applied by applying a 512 point IFFT. In case of using 80MHz bandwidth, 12.8us signal with 1.6us period is made by applying 1024 point IFFT. One 2us OOK waveform can be formed by selecting one of the first, second, third, fourth, fifth, sixth, seventh, and last 1.6us signals among 12.8us signals and inserting 0.4us CP.

If all sub-bands are configured at high data rates, using a 7 length sequence is preferred in terms of implementation, PAPR, and performance. If all WUR PPDUs are set to high data rate, the STA or group that needs to be transmitted at the actual low data rate may have a performance problem when receiving the high data rate through multi-band transmission. It is necessary to transmit at a low data rate, so the delay is large.

2) All sub-bands are configured at low data rates

This is a case where multi-band transmission is performed at low data rate by allocating only STA or group that must be transmitted at low data rate or assigning STA or group capable of high data rate transmission. In this case, 4us on-signal and 4us off-signal are required for 4MHz band within each 20MHz, and can be configured as follows.

A) Use 13 length sequence

A 13 length sequence is allocated to a band corresponding to an on signal among 4 MHz bands within each 20 MHz of 40 MHz and 80 MHz, and the allocation method is the same as A) of 1).

In case of using 40MHz bandwidth by assigning sequence to only 4MHz band corresponding to on-signal and all remaining subcarriers, 3.2us signal is made by applying 128 point IFFT. In case of using 80MHz bandwidth, 3.2us signal is made by applying 256 point IFFT. A 0.8us CP can be inserted into a 3.2us signal to form a 4us OOK waveform.

In case of using 11ax numerology (4x), assign as A) of 1) and form waveform as below.

In case of using 40MHz bandwidth by assigning sequence only to 4MHz band corresponding to on-signal and all remaining subcarriers, 1512us signal with 3.2us period is created by applying 512 point IFFT. In case of using 80MHz bandwidth, 12.8us signal with 3.2us period is made by applying 1024 point IFFT. A 4us OOK waveform can be formed by selecting one of the first, second, third and fourth 3.2us signals among 12.8us signals and inserting 0.8us CP.

B) Use 7 length sequence

A 7 length sequence is allocated to a band corresponding to an on signal among 4MHz bands within 20MHz of 40MHz and 80MHz, and the allocation method is the same as B) of 1).

In case of using 40MHz bandwidth by assigning sequence only to 4MHz band corresponding to on-signal and all other subcarriers, when using 40MHz bandwidth, 3.2us signal having 1.6us period is created by applying 128 point IFFT. In case of using 80MHz bandwidth, 3.2us signal with 1.6us period is made by applying 256 point IFFT. You can select the first or last 1.6us signal among 3.2us signals and insert 0.4us CP to make 2us signal and repeat it twice to form 4us OOK waveform.

In case of using 11ax numerology, assign as in B) of 1) and form waveform as below.

In case of using 40MHz bandwidth by assigning sequence only to 4MHz band corresponding to on-signal and all remaining subcarriers, 12.8us signal having 1.6us period is created by applying 512 point IFFT. In case of using 80MHz bandwidth, 12.8us signal with 1.6us period is made by applying 1024 point IFFT. Select one of the first, second, third, fourth, fifth, sixth, seventh, and last 1.6us signals among the 12.8us signals, insert a 0.4us CP to create a 2us signal, and repeat the 4us OOK waveform Can be formed.

If all sub-bands are configured at low data rates, using a 13 length sequence is preferred in terms of implementation, PAPR, and performance. When all WUR PPDUs are set to a low data rate, there is a disadvantage in that overhead is increased when a STA or a group having no performance problem is received at a low data rate through multi-band transmission even if a high data rate is transmitted.

Or consider 4us on-signal, off-signal as 2us based on-signal, off-signal (i.e. 4us on-signal is 2us on-signal + 2us on-signal, 4us off-signal is 2us off-signal + 2us off-signal) It may be proposed to apply the 2us waveform generation of 1). In this way, the waveform generation for multi-band transmission can be unified based on 2us, and the implementation can be simplified.

3) Some sub-bands have a high data rate and some sub-bands have a low data rate. Common case

In the case of 1) and 2) above, it is necessary to transmit data at the same data rate, which may cause problems such as performance, overhead, and delay. Therefore, it may be advantageous in terms of efficiency or performance to allocate multi-band transmission by assigning an appropriate data rate to each STA or group. However, in this case, some 4MHz bands with high data rates require 2us on signal and 2us off-signal, while some 4MHz bands with low data rate use 4us on-signal and 4us off-signal. This is necessary. Since 2us and 4us cannot be generated at the same time with one IFFT operation, it is necessary to define the basic signal unit and generate the waveform based on this. Therefore, it is preferable to form a waveform by setting the basic signal unit to 2us, which is the minimum unit, and it is conceivable to convert a low data rate symbol configuration into a 2us unit as follows.

Input bit	MC- OOK  modulated symbol
0	[SymHDROn, SymHDROn, SymHDROff, SymHDROff, SymHDROn, SymHDROn, SymHDROff, SymHDROff]
One	[SymHDROff, SymHDROff, SymHDROn, SymHDROn, SymHDROff, SymHDROff, SymHDROn, SymHDROn]

That is, Table 20 shows the conversion of SymLDROn and SymLDROff in Table 17 in 2us units. According to Table 20, SymLDROn is represented as SymHDROn + SymHDROn, and SymLDROff is represented as SymHDROff + SymHDROff. In Table 20, SymHDROn and SymHDROff correspond to 2us On-signal and 2us Off-signal as shown in Table 18. That is, SymHDROn means 2us On-signal and SymHDROff means 2us Off-signal.

That is, in this embodiment, the configuration of a symbol using a high data rate may be defined as shown in Table 18, and the configuration of a symbol using a low data rate may be defined as shown in Table 20.

2us waveform formation is the same as 2us on-signal and 2us off-signal when all sub-bands of 1) are configured at high data rate.

As an example, assume that STA1 is allocated to the 4MHz band in the first 20MHz at 40MHz and STA2 is allocated to the 4MHz band in the second 20MHz. STA1 will transmit at high data rate and STA2 will transmit at low data rate. The data of STA1 is 1 0 1 0 (see Table 18) and the data of STA2 is 1 (see Table 20). In this case, signal configuration is as follows.

STA1: SymHDROff, SymHDROn, SymHDROn, SymHDROff, SymHDROff, SymHDROn, SymHDROn, SymHDROff

STA2: SymHDROff, SymHDROff, SymHDROn, SymHDROn, SymHDROff, SymHDROff, SymHDROn, SymHDROn

Since both first 2us waveforms are off symbols (both SymHDROff), a 2us waveform is formed by assigning a coefficient of 0 to all subcarriers within 40MHz.

In the second 2us waveform, since only STA1 is an on symbol (SymHDROn), a sequence is allocated only to the 4MHz band of the first 20 MHz and a coefficient of 0 is allocated to all remaining subcarriers to form a 2us waveform.

Since the third 2us waveforms are both on symbols (both SymHDROn), a sequence is allocated to the 4MHz bands of the first and second 20 MHz, and a coefficient of 0 is assigned to the remaining subcarriers to form a 2us waveform.

In the fourth 2us waveform, since only STA2 is an on symbol (SymHDROn), a sequence is allocated only to the second 4 MHz band of 20 MHz and a coefficient of 0 is allocated to all remaining subcarriers to form a 2us waveform.

Since the fifth 2us waveform is both an off symbol (both SymHDROff), a 2us waveform is formed by assigning a coefficient of 0 to all subcarriers within 40MHz.

In the sixth 2us waveform, since only STA1 is an on symbol (SymHDROn), a sequence is allocated only to the first 4 MHz band of 20 MHz and a coefficient of 0 is allocated to the remaining subcarriers to form a 2us waveform.

Since the seventh 2us waveforms are both on symbols (both SymHDROn), a sequence is allocated to the 4MHz bands of the first and second 20 MHz, and a coefficient of 0 is assigned to the remaining subcarriers to form a 2us waveform.

In the eighth 2us waveform, since only STA2 is an on symbol (SymHDROn), a sequence is allocated only to the second 4 MHz band of 20 MHz and a coefficient of 0 is allocated to all remaining subcarriers to form a 2us waveform.

C. OOK  waveform generation for the WUR  Sync part

A proposal regarding the waveform generation of the WUR Sync part is as follows. Since the bit duration of the WUR Sync part is 2us, a method of forming a 2us waveform as in the case of 1) of B may be applied.

In the case of multi-band transmission, except for the WUR data part in which all sub-bands use only a low data rate, the wake-up signal may form a waveform every 2us using a 2us waveform generation method. WUR data part that all sub-bands use low data rate can also apply 2us waveform generation method every 2us for unification and simple implementation, or 4us waveform generation method every 4us to reduce the number of generation. Can be.

The center coefficient of the 7/13 length sequence used in the above 40MHz or 80MHz may not be a zero coefficient because it is not DC of 40MHz and 80MHz. Of course, the receiver receives the signal based on 4MHz and the DC offset occurs because the center coefficient of the 7/13 length sequence corresponds to DC, but the performance deterioration does not occur due to the characteristics of the envelope detector.

29 is a flowchart illustrating a procedure of transmitting a wake-up packet by applying the OOK scheme according to the present embodiment.

An example of FIG. 29 is performed in a transmitter, the receiver may correspond to a low power wake-up receiver, and the transmitter may correspond to an AP. This embodiment describes a case where a wake-up packet transmitted to wake up a primary radio is transmitted to a plurality of receivers through a plurality of bands (multi-band or multi-channel). The transmission of the WUR PPDU through a plurality of bands may be regarded as the transmission of a WUR PPDU per 20 MHz in a plurality of bands by applying a frequency division multiplexing access (FDMA) scheme. Therefore, this embodiment can be said that WUR FDMA is applied.

First of all, the term “on signal” may correspond to a signal having an actual power value. The off signal may correspond to a signal that does not have an actual power value. The plurality of bands may be 40 MHz, 80 MHz, or 160 MHz.

In operation S2910, the transmitter generates a first wakeup packet having a first data rate and a second wakeup packet having a second data rate.

In operation S2920, the transmitter transmits the first wakeup packet through a first band and transmits the second wakeup packet through a second band.

How the wakeup packet is configured in the present embodiment is as follows.

On-Off Keying (OOK) is applied to the first and second wake-up packets. The first wakeup packet includes a first on signal or a first off signal. The second wakeup packet includes a second on signal or a second off signal.

The first on signal is generated by inserting a first sequence into 13 consecutive subcarriers in the first band and performing an inverse fast fourier transform (IFFT). The second on signal is generated by inserting a second sequence into 13 consecutive subcarriers in the second band and performing IFFT.

The first off signal may be generated by inserting only 0 without inserting a first sequence into 13 consecutive subcarriers in the first band. The second off signal may also be generated by inserting only 0 without inserting a second sequence into 13 consecutive subcarriers in the second band.

That is, in the first band, an on signal may be transmitted or an off signal may be transmitted. In the second band, an on signal may be transmitted or an off signal may be transmitted. That is, the 2us waveform to be described later may be generated according to a combination of an on-signal or an off-signal for each band.

The generation method of the on signal may be classified into two types as follows.

In a first manner, by inserting a first sequence for a first band and performing a first IFFT to generate an on signal for the first band, inserting a second sequence for a second band and performing a second IFFT An on signal for the second band may be generated. That is, the IFFT is performed in each 20MHz band to form an ON signal for each band.

In a second method, an on-signal may be generated by inserting a first sequence in a first band and inserting a second sequence in a second band to perform one IFFT for the entire band. In this case, the IFFT size may be determined based on the entire band.

In addition, when an off signal is transmitted in a specific band, an off signal may be generated by inserting only 0 without inserting a sequence. That is, the 2us waveform to be described later may be generated according to a combination of an on-signal or an off-signal for each band.

However, the following embodiment will be described as configuring the on-signal using the second scheme.

The length of the first and second sequences is seven. However, data rates of the first and second wakeup packets are different. For example, the first data rate may be 250 Kbps, and the second data rate may be 62.5 Kbps. At 250 Kbps, it is HDR (High Data Rate). At 62.5 Kbps, it is Low Data Rate (LDR). In 802.11ba, a 2us long on-signal is generated using a 7-length sequence in the case of HDR, and a 4us long on-signal is generated using a 13-length sequence in the case of an LDR.

In the present embodiment, HDR may be applied to some of the first to second bands, and LDR may be applied to other portions. Therefore, forming a 2us on signal (or 2us waveform) is preferable in terms of implementation, PAPR, and performance. That is, the transmitting device may perform a single IFFT to form a 2us on signal that is a basic signal unit.

Therefore, in the present embodiment, it is assumed that LDR is also generated by using a sequence of length 7 as in the case of HDR by configuring an on signal having a 4us length as a 2us on signal + a 2us on signal. Similarly, in the case of LDR, the 4us long off signal may be configured as a 2us off signal + a 2us off signal.

For example, when the entire band is 40 MHz, the first band is the first 20 MHz of the 40 MHz, and the second band is the second 20 MHz of the 40 MHz, the coefficient of the first sequence is a subcarrier index Inserted into a subcarrier of -38, -36, -34, -32, -30, -28, or -26, and the coefficient of the second sequence has a subcarrier index of 26, 28, 30, 32, 34, 36, It is inserted into a subcarrier of 38. That is, since the lengths of the first and second sequences are seven, it can be seen that they are actually inserted into seven subcarriers. Accordingly, 0 is inserted in a subcarrier in which the coefficients of the first sequence are not inserted in 13 consecutive subcarriers in the first band and 0 in the 13 consecutive subcarriers in the second band. Zero subcarriers may be inserted for subcarriers without coefficients.

When transmitting a wake-up packet through a plurality of bands, the entire subbands and subcarrier indexes for each band may be determined as follows.

In the first embodiment, it is assumed that the entire band is 40 MHz, the first band is the first 20 MHz of the 40 MHz, and the second band is the second 20 MHz of the 40 MHz.

The first band may include a subcarrier having a subcarrier index of -64 to -1. The second band may include a subcarrier having a subcarrier index of 0 to 63.

The subcarrier indexes of the 13 consecutive subcarriers in the first band may be -38 to -26. The subcarrier indexes of the 13 consecutive subcarriers in the second band may be 26 to 38.

Since the entire band is 40 MHz, the IFFT may be a 128-point IFFT. Coefficients may be inserted into a first subcarrier into which the first to second sequences are inserted in the entire band. 0 may be inserted into the remaining second subcarriers except the first subcarrier in the entire band. Thus, power can be loaded only for the 4 MHz band for transmitting the actual WUR signal.

The specific generation process of the ON signal is as follows.

The first periodic signal generated by inserting the first sequence in 13 consecutive subcarriers in the first band and performing a 128-point IFFT may be a 3.2us long signal having a 1.6us long period. The first on signal may be generated by selecting a 1.6us long signal from the first periodic signal and inserting a first cyclic prefix (CP).

The second periodic signal generated by inserting the second sequence in 13 consecutive subcarriers in the second band and performing a 128-point IFFT may be a 3.2us long signal having a 1.6us long period. The second on signal may be generated by selecting a 1.6us length signal from the second periodic signal and inserting a second CP. The length of the first and second CP is 0.4us.

In a second embodiment, the total band is 80 MHz, the first band is the first 20 MHz of the 80 MHz, the second band is the second 20 MHz of the 80 MHz, and the third band is the third 20 MHz of the 80 MHz Assume that the fourth band is the fourth 20 MHz of the 80 MHz.

In this case, the transmitter may generate a third wakeup packet and a fourth wakeup packet.

The transmitter may transmit the third wakeup packet through a third band and transmit the fourth wakeup packet through a fourth band.

When the total band is 80 MHz, the first band is the first 20 MHz of the 80 MHz, the second band is the second 20 MHz of the 80 MHz, the third band is the third 20 MHz of the 80 MHz, and the fourth The band may be the fourth 20 MHz of the 80 MHz.

A OOK scheme may be applied to the third and fourth wakeup packets, and the third and fourth wakeup packets may have the first data rate or the second data rate.

The third wakeup packet may include a third on signal or a third off signal, and the fourth wakeup packet may include a fourth on signal or a fourth off signal.

The third on signal is generated by inserting a third sequence into 13 consecutive subcarriers in the third band and performing an IFFT, and the fourth on signal is generated into 13 consecutive subcarriers in the fourth band. It can be generated by inserting 4 sequences and performing IFFT.

The third off signal may be generated by inserting only 0 without inserting a third sequence into 13 consecutive subcarriers in the third band. The fourth off signal may also be generated by inserting only zeros without inserting a fourth sequence into 13 consecutive subcarriers in the fourth band.

That is, in the third band, an on signal may be transmitted or an off signal may be transmitted. In the fourth band, an on signal may be transmitted or an off signal may be transmitted. That is, the 2us waveform to be described later may be generated according to a combination of an on-signal or an off-signal for each band.

The generation method of the on signal may be classified into two types as follows.

In a first manner, by inserting a first sequence for a first band and performing a first IFFT to generate an on signal for the first band, inserting a second sequence for a second band and performing a second IFFT An on signal for the second band may be generated. Also, inserting a third sequence for the third band and performing a third IFFT to generate an on signal for the third band, inserting a fourth sequence for the fourth band and performing a fourth IFFT to perform the fourth band It can generate an on signal for. That is, the IFFT is performed in each 20MHz band to form an ON signal for each band.

In a second manner, inserting the first sequence in the first band, inserting the second sequence in the second band, inserting the third sequence in the third band, inserting the fourth sequence in the fourth band and the full band One IFFT can be performed on to generate an on signal. In this case, the IFFT size may be determined based on the entire band.

In addition, when an off signal is transmitted in a specific band, an off signal may be generated by inserting only 0 without inserting a sequence. That is, the 2us waveform to be described later may be generated according to a combination of an on-signal or an off-signal for each band.

However, the following embodiment will be described as configuring the on-signal using the second scheme.

The length of the third and fourth sequences is seven. As described above, in the present embodiment, HDR may be applied to some of the first to fourth bands, and LDR may be applied to other portions, so that a 2us on signal (or 2us waveform) is formed in terms of implementation, PAPR, and performance. do. That is, the transmitting device may perform a single IFFT to form a 2us on signal that is a basic signal unit.

Therefore, in the present embodiment, it is assumed that LDR is also generated by using a sequence of length 7 as in the case of HDR by configuring an on signal having a 4us length as a 2us on signal + a 2us on signal. Similarly, in the case of LDR, the 4us long off signal may be configured as a 2us off signal + a 2us off signal.

When the full band is 80 MHz, the coefficients of the first sequence may be inserted into subcarriers having subcarrier indices of -102, -100, -98, -96, -94, -92, and -90. Coefficients of the second sequence may be inserted into subcarriers having subcarrier indices of -38, -36, -34, -32, -30, -28, and -26. Coefficients of the third sequence may be inserted into subcarriers having 26, 28, 30, 32, 34, 36, and 38 subcarrier indices. The coefficients of the fourth sequence may be inserted into subcarriers having 90, 92, 94, 96, 98, 100, and 102 subcarrier indices. That is, since the lengths of the first to fourth sequences are seven, it can be seen that they are actually inserted into seven subcarriers. Accordingly, 0 may be inserted into subcarriers in which the coefficients of the first sequence are not inserted in 13 consecutive subcarriers in the first band. In the 13 consecutive subcarriers in the second band, 0 may be inserted in a subcarrier in which the coefficient of the second sequence is not inserted. Zero subcarriers may be inserted in subcarriers in which the coefficients of the third sequence are not inserted in thirteen consecutive subcarriers in the third band. Zero subcarriers may be inserted in subcarriers in which the coefficients of the fourth sequence are not inserted in thirteen consecutive subcarriers in the fourth band.

When transmitting a wake-up packet through a plurality of bands, the entire subbands and subcarrier indexes for each band may be determined as follows.

The first band may include a subcarrier having a subcarrier index of -128 to -65. The second band may include a subcarrier having a subcarrier index of -64 to -1. The third band may include a subcarrier having a subcarrier index of 0 to 63. The fourth band may include a subcarrier having a subcarrier index of 64 to 127.

Subcarrier indices of 13 consecutive subcarriers in the first band may be -102 to -90. Subcarrier indices of 13 consecutive subcarriers in the second band may be -38 to -26. The subcarrier indexes of the 13 consecutive subcarriers in the third band may be 26 to 38. The subcarrier indexes of the 13 consecutive subcarriers in the fourth band may be 64 to 127.

Since the entire band is 80 MHz, the IFFT may be a 256-point IFFT. Coefficients may be inserted into a first subcarrier into which the first to fourth sequences are inserted in the entire band. 0 may be inserted into the remaining second subcarriers except the first subcarrier in the entire band. Thus, power can be loaded only for the 4 MHz band for transmitting the actual WUR signal.

The specific generation process of the ON signal is as follows.

The first periodic signal generated by inserting the first sequence in 13 consecutive subcarriers in the first band and performing a 256-point IFFT may be a 3.2us long signal having a 1.6us long period. The first on signal may be generated by selecting a 1.6us length signal from the first periodic signal and inserting a first CP.

The second periodic signal generated by inserting the second sequence in 13 consecutive subcarriers in the second band and performing a 256-point IFFT may be a 3.2us long signal having a 1.6us long period. The second on signal may be generated by selecting a 1.6us length signal from the second periodic signal and inserting a second CP.

The third periodic signal generated by inserting the third sequence in 13 consecutive subcarriers in the third band and performing a 256-point IFFT may be a 3.2us long signal having a 1.6us long period. The third on signal may be generated by selecting a 1.6us long signal from the third periodic signal and inserting a third CP.

The fourth periodic signal generated by inserting the fourth sequence in 13 consecutive subcarriers in the fourth band and performing a 256-point IFFT may be a 3.2us long signal having a 1.6us long period. The fourth on signal may be generated by selecting a 1.6us long signal from the fourth periodic signal and inserting a fourth CP. The length of the first to fourth CP is 0.4us.

In addition, 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.

30 is a flowchart illustrating a procedure of receiving a wakeup packet by applying the OOK method according to the present embodiment.

An example of FIG. 30 is performed in a receiving apparatus, which may correspond to a low power wake-up receiver, and the transmitting apparatus may correspond to an AP. This embodiment describes a case where a wake-up packet transmitted to wake up a primary radio is transmitted to a plurality of receivers through a plurality of bands (multi-band or multi-channel). In this case, a method for configuring a frequency sequence used to generate a wakeup packet in terms of frequency in order to reduce PAPR generated by simultaneously transmitting wakeup packets to a plurality of STAs is proposed. The transmission of the WUR PPDU through a plurality of bands may be regarded as the transmission of a WUR PPDU per 20 MHz in a plurality of bands by applying a frequency division multiplexing access (FDMA) scheme. Therefore, this embodiment can be said that WUR FDMA is applied.

In addition, according to the present embodiment, one of a plurality of receivers may receive a wakeup packet through the plurality of bands, and may decode the wakeup packet for a band supported by the receiver.

First of all, the term “on signal” may correspond to a signal having an actual power value. The off signal may correspond to a signal that does not have an actual power value. The plurality of bands may be 40 MHz, 80 MHz, or 160 MHz.

In operation S3010, the receiving apparatus receives a first wakeup packet having a first data rate and a second wakeup packet having a second data rate.

In operation S3020, the receiver decodes the first wakeup packet or the second wakeup packet for a band supported by the receiver.

How the wakeup packet is configured in the present embodiment is as follows.

On-Off Keying (OOK) is applied to the first and second wake-up packets. The first wakeup packet includes a first on signal or a first off signal. The second wakeup packet includes a second on signal or a second off signal.

The first on signal is generated by inserting a first sequence into 13 consecutive subcarriers in the first band and performing an inverse fast fourier transform (IFFT). The second on signal is generated by inserting a second sequence into 13 consecutive subcarriers in the second band and performing IFFT.

The first off signal may be generated by inserting only 0 without inserting a first sequence into 13 consecutive subcarriers in the first band. The second off signal may also be generated by inserting only 0 without inserting a second sequence into 13 consecutive subcarriers in the second band.

That is, in the first band, an on signal may be transmitted or an off signal may be transmitted. In the second band, an on signal may be transmitted or an off signal may be transmitted. That is, the 2us waveform to be described later may be generated according to a combination of an on-signal or an off-signal for each band.

The generation method of the on signal may be classified into two types as follows.

In a first manner, by inserting a first sequence for a first band and performing a first IFFT to generate an on signal for the first band, inserting a second sequence for a second band and performing a second IFFT An on signal for the second band may be generated. That is, the IFFT is performed in each 20MHz band to form an ON signal for each band.

In a second method, an on-signal may be generated by inserting a first sequence in a first band and inserting a second sequence in a second band to perform one IFFT for the entire band. In this case, the IFFT size may be determined based on the entire band.

In addition, when an off signal is transmitted in a specific band, an off signal may be generated by inserting only 0 without inserting a sequence. That is, the 2us waveform to be described later may be generated according to a combination of an on-signal or an off-signal for each band.

However, the following embodiment will be described as configuring the on-signal using the second scheme.

The length of the first and second sequences is seven. However, data rates of the first and second wakeup packets are different. For example, the first data rate may be 250 Kbps, and the second data rate may be 62.5 Kbps. At 250 Kbps, it is HDR (High Data Rate). At 62.5 Kbps, it is Low Data Rate (LDR). In 802.11ba, a 2us long on-signal is generated using a 7-length sequence in the case of HDR, and a 4us long on-signal is generated using a 13-length sequence in the case of an LDR.

In the present embodiment, HDR may be applied to some of the first to second bands, and LDR may be applied to other portions. Therefore, forming a 2us on signal (or 2us waveform) is preferable in terms of implementation, PAPR, and performance. That is, the transmitting device may perform a single IFFT to form a 2us on signal that is a basic signal unit.

Therefore, in the present embodiment, it is assumed that LDR is also generated by using a sequence of length 7 as in the case of HDR by configuring an on signal having a 4us length as a 2us on signal + a 2us on signal. Similarly, in the case of LDR, the 4us long off signal may be configured as a 2us off signal + a 2us off signal.

For example, when the entire band is 40 MHz, the first band is the first 20 MHz of the 40 MHz, and the second band is the second 20 MHz of the 40 MHz, the coefficient of the first sequence is a subcarrier index Inserted into a subcarrier of -38, -36, -34, -32, -30, -28, or -26, and the coefficient of the second sequence has a subcarrier index of 26, 28, 30, 32, 34, 36, It is inserted into a subcarrier of 38. That is, since the lengths of the first and second sequences are seven, it can be seen that they are actually inserted into seven subcarriers. Accordingly, 0 is inserted in a subcarrier in which the coefficients of the first sequence are not inserted in 13 consecutive subcarriers in the first band and 0 in the 13 consecutive subcarriers in the second band. Zero subcarriers may be inserted for subcarriers without coefficients.

When transmitting a wake-up packet through a plurality of bands, the entire subbands and subcarrier indexes for each band may be determined as follows.

In the first embodiment, it is assumed that the entire band is 40 MHz, the first band is the first 20 MHz of the 40 MHz, and the second band is the second 20 MHz of the 40 MHz.

The first band may include a subcarrier having a subcarrier index of -64 to -1. The second band may include a subcarrier having a subcarrier index of 0 to 63.

The subcarrier indexes of the 13 consecutive subcarriers in the first band may be -38 to -26. The subcarrier indexes of the 13 consecutive subcarriers in the second band may be 26 to 38.

Since the entire band is 40 MHz, the IFFT may be a 128-point IFFT. Coefficients may be inserted into a first subcarrier into which the first to second sequences are inserted in the entire band. 0 may be inserted into the remaining second subcarriers except the first subcarrier in the entire band. Thus, power can be loaded only for the 4 MHz band for transmitting the actual WUR signal.

The specific generation process of the ON signal is as follows.

The first periodic signal generated by inserting the first sequence in 13 consecutive subcarriers in the first band and performing a 128-point IFFT may be a 3.2us long signal having a 1.6us long period. The first on signal may be generated by selecting a 1.6us long signal from the first periodic signal and inserting a first cyclic prefix (CP).

The second periodic signal generated by inserting the second sequence in 13 consecutive subcarriers in the second band and performing a 128-point IFFT may be a 3.2us long signal having a 1.6us long period. The second on signal may be generated by selecting a 1.6us length signal from the second periodic signal and inserting a second CP. The length of the first and second CP is 0.4us.

In a second embodiment, the total band is 80 MHz, the first band is the first 20 MHz of the 80 MHz, the second band is the second 20 MHz of the 80 MHz, and the third band is the third 20 MHz of the 80 MHz Assume that the fourth band is the fourth 20 MHz of the 80 MHz.

In this case, the transmitter may generate a third wakeup packet and a fourth wakeup packet.

The transmitter may transmit the third wakeup packet through a third band and transmit the fourth wakeup packet through a fourth band.

When the total band is 80 MHz, the first band is the first 20 MHz of the 80 MHz, the second band is the second 20 MHz of the 80 MHz, the third band is the third 20 MHz of the 80 MHz, and the fourth The band may be the fourth 20 MHz of the 80 MHz.

A OOK scheme may be applied to the third and fourth wakeup packets, and the third and fourth wakeup packets may have the first data rate or the second data rate.

The third wakeup packet may include a third on signal or a third off signal, and the fourth wakeup packet may include a fourth on signal or a fourth off signal.

The third on signal is generated by inserting a third sequence into 13 consecutive subcarriers in the third band and performing an IFFT, and the fourth on signal is generated into 13 consecutive subcarriers in the fourth band. It can be generated by inserting 4 sequences and performing IFFT.

The third off signal may be generated by inserting only 0 without inserting a third sequence into 13 consecutive subcarriers in the third band. The fourth off signal may also be generated by inserting only zeros without inserting a fourth sequence into 13 consecutive subcarriers in the fourth band.

That is, in the third band, an on signal may be transmitted or an off signal may be transmitted. In the fourth band, an on signal may be transmitted or an off signal may be transmitted. That is, the 2us waveform to be described later may be generated according to a combination of an on-signal or an off-signal for each band.

The generation method of the on signal may be classified into two types as follows.

In a first manner, by inserting a first sequence for a first band and performing a first IFFT to generate an on signal for the first band, inserting a second sequence for a second band and performing a second IFFT An on signal for the second band may be generated. Also, inserting a third sequence for the third band and performing a third IFFT to generate an on signal for the third band, inserting a fourth sequence for the fourth band and performing a fourth IFFT to perform the fourth band It can generate an on signal for. That is, the IFFT is performed in each 20MHz band to form an ON signal for each band.

In a second manner, inserting the first sequence in the first band, inserting the second sequence in the second band, inserting the third sequence in the third band, inserting the fourth sequence in the fourth band and the full band One IFFT can be performed on to generate an on signal. In this case, the IFFT size may be determined based on the entire band.

In addition, when an off signal is transmitted in a specific band, an off signal may be generated by inserting only 0 without inserting a sequence. That is, the 2us waveform to be described later may be generated according to a combination of an on-signal or an off-signal for each band.

However, the following embodiment will be described as configuring the on-signal using the second scheme.

The length of the third and fourth sequences is seven. As described above, in the present embodiment, HDR may be applied to some of the first to fourth bands, and LDR may be applied to other portions, so that a 2us on signal (or 2us waveform) is formed in terms of implementation, PAPR, and performance. do. That is, the transmitting device may perform a single IFFT to form a 2us on signal that is a basic signal unit.

Therefore, in the present embodiment, it is assumed that LDR is also generated by using a sequence of length 7 as in the case of HDR by configuring an on signal having a 4us length as a 2us on signal + a 2us on signal. Similarly, in the case of LDR, the 4us long off signal may be configured as a 2us off signal + a 2us off signal.

When the full band is 80 MHz, the coefficients of the first sequence may be inserted into subcarriers having subcarrier indices of -102, -100, -98, -96, -94, -92, and -90. Coefficients of the second sequence may be inserted into subcarriers having subcarrier indices of -38, -36, -34, -32, -30, -28, and -26. Coefficients of the third sequence may be inserted into subcarriers having 26, 28, 30, 32, 34, 36, and 38 subcarrier indices. The coefficients of the fourth sequence may be inserted into subcarriers having 90, 92, 94, 96, 98, 100, and 102 subcarrier indices. That is, since the lengths of the first to fourth sequences are seven, it can be seen that they are actually inserted into seven subcarriers. Accordingly, 0 may be inserted into subcarriers in which the coefficients of the first sequence are not inserted in 13 consecutive subcarriers in the first band. In the 13 consecutive subcarriers in the second band, 0 may be inserted in a subcarrier in which the coefficient of the second sequence is not inserted. Zero subcarriers may be inserted in subcarriers in which the coefficients of the third sequence are not inserted in thirteen consecutive subcarriers in the third band. Zero subcarriers may be inserted in subcarriers in which the coefficients of the fourth sequence are not inserted in thirteen consecutive subcarriers in the fourth band.

When transmitting a wake-up packet through a plurality of bands, the entire subbands and subcarrier indexes for each band may be determined as follows.

The first band may include a subcarrier having a subcarrier index of -128 to -65. The second band may include a subcarrier having a subcarrier index of -64 to -1. The third band may include a subcarrier having a subcarrier index of 0 to 63. The fourth band may include a subcarrier having a subcarrier index of 64 to 127.

Subcarrier indices of 13 consecutive subcarriers in the first band may be -102 to -90. Subcarrier indices of 13 consecutive subcarriers in the second band may be -38 to -26. The subcarrier indexes of the 13 consecutive subcarriers in the third band may be 26 to 38. The subcarrier indexes of the 13 consecutive subcarriers in the fourth band may be 64 to 127.

Since the entire band is 80 MHz, the IFFT may be a 256-point IFFT. Coefficients may be inserted into a first subcarrier into which the first to fourth sequences are inserted in the entire band. 0 may be inserted into the remaining second subcarriers except the first subcarrier in the entire band. Thus, power can be loaded only for the 4 MHz band for transmitting the actual WUR signal.

The specific generation process of the ON signal is as follows.

The first periodic signal generated by inserting the first sequence in 13 consecutive subcarriers in the first band and performing a 256-point IFFT may be a 3.2us long signal having a 1.6us long period. The first on signal may be generated by selecting a 1.6us length signal from the first periodic signal and inserting a first CP.

The second periodic signal generated by inserting the second sequence in 13 consecutive subcarriers in the second band and performing a 256-point IFFT may be a 3.2us long signal having a 1.6us long period. The second on signal may be generated by selecting a 1.6us length signal from the second periodic signal and inserting a second CP.

The third periodic signal generated by inserting the third sequence in 13 consecutive subcarriers in the third band and performing a 256-point IFFT may be a 3.2us long signal having a 1.6us long period. The third on signal may be generated by selecting a 1.6us long signal from the third periodic signal and inserting a third CP.

The fourth periodic signal generated by inserting the fourth sequence in 13 consecutive subcarriers in the fourth band and performing a 256-point IFFT may be a 3.2us long signal having a 1.6us long period. The fourth on signal may be generated by selecting a 1.6us long signal from the fourth periodic signal and inserting a fourth CP. The length of the first to fourth CP is 0.4us.

In addition, 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.

Device configuration

FIG. 31 illustrates an apparatus for implementing the method as described above.

The wireless device 100 of FIG. 31 is a transmission device capable of implementing the above-described embodiment and may operate as an AP STA. The wireless device 150 of FIG. 31 is a reception device capable of implementing the above-described embodiment and may operate as a non-AP STA.

The transmitter 100 may include a processor 110, a memory 120, and a transceiver 130, and the receiver device 150 may include a processor 160, a memory 170, and a transceiver 180. can do. The transceiver 130 and 180 may transmit / receive a radio signal and may be executed in a physical layer such as IEEE 802.11 / 3GPP. The processors 110 and 160 are executed in the physical layer and / or the MAC layer and are connected to the transceivers 130 and 180.

The processors 110 and 160 and / or the transceivers 130 and 180 may include application-specific integrated circuits (ASICs), other chipsets, logic circuits, and / or data processors. The memory 120, 170 may include read-only memory (ROM), random access memory (RAM), flash memory, memory card, storage medium and / or other storage unit. When an embodiment is executed by software, the method described above can be executed as a module (eg, process, function) that performs the functions described above. The module may be stored in the memories 120 and 170 and may be executed by the processors 110 and 160. The memories 120 and 170 may be disposed inside or outside the processes 110 and 160, and may be connected to the processes 110 and 160 by well-known means.

The processors 110 and 160 may implement the functions, processes, and / or methods proposed herein. For example, the processors 110 and 160 may perform operations according to the above-described embodiment.

The operation of the processor 110 of the transmitter is specifically as follows. The processor 110 of the transmitting apparatus generates a wakeup packet (first and second wakeup packets) by applying an on-off keying (OOK) scheme, and transmits the wakeup packet to the receiving apparatus through a plurality of bands. do.

The operation of the processor 160 of the receiving apparatus is as follows. The receiving device may be one of a plurality of low power wake-up receivers. The processor 160 of the receiving device receives a wake-up packet (first and second wake-up packet) generated by applying an On-Off Keying (OOK) method through a plurality of bands, and a band supported by the receiving device. Decode the wakeup packet for.

How the wakeup packet is configured in the present embodiment is as follows.

On-Off Keying (OOK) is applied to the first and second wake-up packets. The first wakeup packet includes a first on signal or a first off signal. The second wakeup packet includes a second on signal or a second off signal.

The first on signal is generated by inserting a first sequence into 13 consecutive subcarriers in the first band and performing an inverse fast fourier transform (IFFT). The second on signal is generated by inserting a second sequence into 13 consecutive subcarriers in the second band and performing IFFT.

The first off signal may be generated by inserting only 0 without inserting a first sequence into 13 consecutive subcarriers in the first band. The second off signal may also be generated by inserting only 0 without inserting a second sequence into 13 consecutive subcarriers in the second band.

That is, in the first band, an on signal may be transmitted or an off signal may be transmitted. In the second band, an on signal may be transmitted or an off signal may be transmitted. That is, the 2us waveform to be described later may be generated according to a combination of an on-signal or an off-signal for each band.

The generation method of the on signal may be classified into two types as follows.

In a first manner, by inserting a first sequence for a first band and performing a first IFFT to generate an on signal for the first band, inserting a second sequence for a second band and performing a second IFFT An on signal for the second band may be generated. That is, the IFFT is performed in each 20MHz band to form an ON signal for each band.

In a second method, an on-signal may be generated by inserting a first sequence in a first band and inserting a second sequence in a second band to perform one IFFT for the entire band. In this case, the IFFT size may be determined based on the entire band.

In addition, when an off signal is transmitted in a specific band, an off signal may be generated by inserting only 0 without inserting a sequence. That is, the 2us waveform to be described later may be generated according to a combination of an on-signal or an off-signal for each band.

However, the following embodiment will be described as configuring the on-signal using the second scheme.

The length of the first and second sequences is seven. However, data rates of the first and second wakeup packets are different. For example, the first data rate may be 250 Kbps, and the second data rate may be 62.5 Kbps. At 250 Kbps, it is HDR (High Data Rate). At 62.5 Kbps, it is Low Data Rate (LDR). In 802.11ba, a 2us long on-signal is generated using a 7-length sequence in the case of HDR, and a 4us long on-signal is generated using a 13-length sequence in the case of an LDR.

In the present embodiment, HDR may be applied to some of the first to second bands, and LDR may be applied to other portions. Therefore, forming a 2us on signal (or 2us waveform) is preferable in terms of implementation, PAPR, and performance. That is, the transmitting device may perform a single IFFT to form a 2us on signal that is a basic signal unit.

Therefore, in the present embodiment, it is assumed that LDR is also generated by using a sequence of length 7 as in the case of HDR by configuring an on signal having a 4us length as a 2us on signal + a 2us on signal. Similarly, in the case of LDR, the 4us long off signal may be configured as a 2us off signal + a 2us off signal.

For example, when the entire band is 40 MHz, the first band is the first 20 MHz of the 40 MHz, and the second band is the second 20 MHz of the 40 MHz, the coefficient of the first sequence is a subcarrier index Inserted into a subcarrier of -38, -36, -34, -32, -30, -28, or -26, and the coefficient of the second sequence has a subcarrier index of 26, 28, 30, 32, 34, 36, It is inserted into a subcarrier of 38. That is, since the lengths of the first and second sequences are seven, it can be seen that they are actually inserted into seven subcarriers. Accordingly, 0 is inserted in a subcarrier in which the coefficients of the first sequence are not inserted in 13 consecutive subcarriers in the first band and 0 in the 13 consecutive subcarriers in the second band. Zero subcarriers may be inserted for subcarriers without coefficients.

When transmitting a wake-up packet through a plurality of bands, the entire subbands and subcarrier indexes for each band may be determined as follows.

In the first embodiment, it is assumed that the entire band is 40 MHz, the first band is the first 20 MHz of the 40 MHz, and the second band is the second 20 MHz of the 40 MHz.

The first band may include a subcarrier having a subcarrier index of -64 to -1. The second band may include a subcarrier having a subcarrier index of 0 to 63.

The subcarrier indexes of the 13 consecutive subcarriers in the first band may be -38 to -26. The subcarrier indexes of the 13 consecutive subcarriers in the second band may be 26 to 38.

Since the entire band is 40 MHz, the IFFT may be a 128-point IFFT. Coefficients may be inserted into a first subcarrier into which the first to second sequences are inserted in the entire band. 0 may be inserted into the remaining second subcarriers except the first subcarrier in the entire band. Thus, power can be loaded only for the 4 MHz band for transmitting the actual WUR signal.

The specific generation process of the ON signal is as follows.

The first periodic signal generated by inserting the first sequence in 13 consecutive subcarriers in the first band and performing a 128-point IFFT may be a 3.2us long signal having a 1.6us long period. The first on signal may be generated by selecting a 1.6us long signal from the first periodic signal and inserting a first cyclic prefix (CP).

The second periodic signal generated by inserting the second sequence in 13 consecutive subcarriers in the second band and performing a 128-point IFFT may be a 3.2us long signal having a 1.6us long period. The second on signal may be generated by selecting a 1.6us length signal from the second periodic signal and inserting a second CP. The length of the first and second CP is 0.4us.

In a second embodiment, the total band is 80 MHz, the first band is the first 20 MHz of the 80 MHz, the second band is the second 20 MHz of the 80 MHz, and the third band is the third 20 MHz of the 80 MHz Assume that the fourth band is the fourth 20 MHz of the 80 MHz.

In this case, the transmitter may generate a third wakeup packet and a fourth wakeup packet.

The transmitter may transmit the third wakeup packet through a third band and transmit the fourth wakeup packet through a fourth band.

When the total band is 80 MHz, the first band is the first 20 MHz of the 80 MHz, the second band is the second 20 MHz of the 80 MHz, the third band is the third 20 MHz of the 80 MHz, and the fourth The band may be the fourth 20 MHz of the 80 MHz.

A OOK scheme may be applied to the third and fourth wakeup packets, and the third and fourth wakeup packets may have the first data rate or the second data rate.

The third wakeup packet may include a third on signal or a third off signal, and the fourth wakeup packet may include a fourth on signal or a fourth off signal.

The third on signal is generated by inserting a third sequence into 13 consecutive subcarriers in the third band and performing an IFFT, and the fourth on signal is generated into 13 consecutive subcarriers in the fourth band. It can be generated by inserting 4 sequences and performing IFFT.

The third off signal may be generated by inserting only 0 without inserting a third sequence into 13 consecutive subcarriers in the third band. The fourth off signal may also be generated by inserting only zeros without inserting a fourth sequence into 13 consecutive subcarriers in the fourth band.

That is, in the third band, an on signal may be transmitted or an off signal may be transmitted. In the fourth band, an on signal may be transmitted or an off signal may be transmitted. That is, the 2us waveform to be described later may be generated according to a combination of an on-signal or an off-signal for each band.

The generation method of the on signal may be classified into two types as follows.

In a first manner, by inserting a first sequence for a first band and performing a first IFFT to generate an on signal for the first band, inserting a second sequence for a second band and performing a second IFFT An on signal for the second band may be generated. Also, inserting a third sequence for the third band and performing a third IFFT to generate an on signal for the third band, inserting a fourth sequence for the fourth band and performing a fourth IFFT to perform the fourth band It can generate an on signal for. That is, the IFFT is performed in each 20MHz band to form an ON signal for each band.

In a second manner, inserting the first sequence in the first band, inserting the second sequence in the second band, inserting the third sequence in the third band, inserting the fourth sequence in the fourth band and the full band One IFFT can be performed on to generate an on signal. In this case, the IFFT size may be determined based on the entire band.

In addition, when an off signal is transmitted in a specific band, an off signal may be generated by inserting only 0 without inserting a sequence. That is, the 2us waveform to be described later may be generated according to a combination of an on-signal or an off-signal for each band.

However, the following embodiment will be described as configuring the on-signal using the second scheme.

The length of the third and fourth sequences is seven. As described above, in the present embodiment, HDR may be applied to some of the first to fourth bands, and LDR may be applied to other portions, so that a 2us on signal (or 2us waveform) is formed in terms of implementation, PAPR, and performance. do. That is, the transmitting device may perform a single IFFT to form a 2us on signal that is a basic signal unit.

Therefore, in the present embodiment, it is assumed that LDR is also generated by using a sequence of length 7 as in the case of HDR by configuring an on signal having a 4us length as a 2us on signal + a 2us on signal. Similarly, in the case of LDR, the 4us long off signal may be configured as a 2us off signal + a 2us off signal.

When the full band is 80 MHz, the coefficients of the first sequence may be inserted into subcarriers having subcarrier indices of -102, -100, -98, -96, -94, -92, and -90. Coefficients of the second sequence may be inserted into subcarriers having subcarrier indices of -38, -36, -34, -32, -30, -28, and -26. Coefficients of the third sequence may be inserted into subcarriers having 26, 28, 30, 32, 34, 36, and 38 subcarrier indices. The coefficients of the fourth sequence may be inserted into subcarriers having 90, 92, 94, 96, 98, 100, and 102 subcarrier indices. That is, since the lengths of the first to fourth sequences are seven, it can be seen that they are actually inserted into seven subcarriers. Accordingly, 0 may be inserted into subcarriers in which the coefficients of the first sequence are not inserted in 13 consecutive subcarriers in the first band. In the 13 consecutive subcarriers in the second band, 0 may be inserted in a subcarrier in which the coefficient of the second sequence is not inserted. Zero subcarriers may be inserted in subcarriers in which the coefficients of the third sequence are not inserted in thirteen consecutive subcarriers in the third band. Zero subcarriers may be inserted in subcarriers in which the coefficients of the fourth sequence are not inserted in thirteen consecutive subcarriers in the fourth band.

When transmitting a wake-up packet through a plurality of bands, the entire subbands and subcarrier indexes for each band may be determined as follows.

The first band may include a subcarrier having a subcarrier index of -128 to -65. The second band may include a subcarrier having a subcarrier index of -64 to -1. The third band may include a subcarrier having a subcarrier index of 0 to 63. The fourth band may include a subcarrier having a subcarrier index of 64 to 127.

Subcarrier indices of 13 consecutive subcarriers in the first band may be -102 to -90. Subcarrier indices of 13 consecutive subcarriers in the second band may be -38 to -26. The subcarrier indexes of the 13 consecutive subcarriers in the third band may be 26 to 38. The subcarrier indexes of the 13 consecutive subcarriers in the fourth band may be 64 to 127.

Since the entire band is 80 MHz, the IFFT may be a 256-point IFFT. Coefficients may be inserted into a first subcarrier into which the first to fourth sequences are inserted in the entire band. 0 may be inserted into the remaining second subcarriers except the first subcarrier in the entire band. Thus, power can be loaded only for the 4 MHz band for transmitting the actual WUR signal.

The specific generation process of the ON signal is as follows.

The first periodic signal generated by inserting the first sequence in 13 consecutive subcarriers in the first band and performing a 256-point IFFT may be a 3.2us long signal having a 1.6us long period. The first on signal may be generated by selecting a 1.6us length signal from the first periodic signal and inserting a first CP.

The second periodic signal generated by inserting the second sequence in 13 consecutive subcarriers in the second band and performing a 256-point IFFT may be a 3.2us long signal having a 1.6us long period. The second on signal may be generated by selecting a 1.6us length signal from the second periodic signal and inserting a second CP.

The third periodic signal generated by inserting the third sequence in 13 consecutive subcarriers in the third band and performing a 256-point IFFT may be a 3.2us long signal having a 1.6us long period. The third on signal may be generated by selecting a 1.6us long signal from the third periodic signal and inserting a third CP.

The fourth periodic signal generated by inserting the fourth sequence in 13 consecutive subcarriers in the fourth band and performing a 256-point IFFT may be a 3.2us long signal having a 1.6us long period. The fourth on signal may be generated by selecting a 1.6us long signal from the fourth periodic signal and inserting a fourth CP. The length of the first to fourth CP is 0.4us.

In addition, 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.

Claims (17)

1. In a method for transmitting a wake-up packet in a wireless LAN system,

   Generating, by the transmitting device, a first wakeup packet having a first data rate and a second wakeup packet having a second data rate; And

   The transmitting apparatus, transmitting the first wakeup packet through a first band and transmitting the second wakeup packet through a second band,

   On-Off Keying (OOK) is applied to the first and second wake-up packets.

   The first wakeup packet includes a first on signal or a first off signal.

   The second wake-up packet includes a second on signal or a second off signal,

   The first on signal is generated by inserting a first sequence into 13 consecutive subcarriers in the first band and performing an Inverse Fast Fourier Transform (IFFT).

   The second on signal is generated by inserting a second sequence into 13 consecutive subcarriers in the second band and performing the IFFT,

   The length of the first and second sequences is 7,

   When the total band is 40 MHz, the first band is the first 20 MHz of the 40 MHz, and the second band is the second 20 MHz of the 40 MHz,

   Coefficients of the first sequence are inserted into subcarriers having subcarrier indices of -38, -36, -34, -32, -30, -28, -26, and

   The coefficients of the second sequence are inserted into subcarriers with subcarrier indices of 26, 28, 30, 32, 34, 36, 38.

   Way.
2. The method of claim 1,

   The first band includes a subcarrier having a subcarrier index of -64 to -1,

   The second band includes subcarriers having a subcarrier index of 0 to 63,

   Subcarrier indices of 13 consecutive subcarriers in the first band are -38 to -26,

   The subcarrier indexes of the 13 consecutive subcarriers in the second band are 26 to 38.

   Way.
3. The method of claim 2,

   The IFFT is a 128-point IFFT,

   Coefficients are inserted into a first subcarrier into which the first to second sequences are inserted in the entire band.

   0 is inserted into the remaining second subcarriers except the first subcarrier in the entire band.

   Way.
4. The method of claim 1,

   0 is inserted in a subcarrier in which the coefficients of the first sequence are not inserted in 13 consecutive subcarriers in the first band,

   0 is inserted in a subcarrier in which the coefficients of the second sequence are not inserted in 13 consecutive subcarriers in the second band,

   The first periodic signal generated by inserting the first sequence in 13 consecutive subcarriers in the first band and performing the 128-point IFFT is a 3.2us long signal having a 1.6us long period,

   The first on signal is generated by selecting a 1.6us length signal from the first periodic signal and inserting a first cyclic prefix (CP).

   The second periodic signal generated by inserting the second sequence in 13 consecutive subcarriers in the second band and performing the 128-point IFFT is a 3.2us long signal having a 1.6us long period,

   The second on signal is generated by selecting a 1.6us long signal from the second periodic signal and inserting a second CP.

   The length of the first and second CP is 0.4us

   Way.
5. The method of claim 1,

   If the entire band is 80MHz,

   Generating, by the transmitter, a third wakeup packet and a fourth wakeup packet; And

   The transmitting apparatus further comprises: transmitting the third wakeup packet through a third band and transmitting the fourth wakeup packet through a fourth band,

   The first band is the first 20 MHz of the 80 MHz,

   The second band is the second 20 MHz of the 80 MHz,

   The third band is the third 20 MHz of the 80 MHz,

   The fourth band is the fourth 20 MHz of the 80 MHz,

   OOK scheme is applied to the third and fourth wakeup packets,

   The third and fourth wakeup packets have the first data rate or the second data rate.

   Way.
6. The method of claim 5,

   If the entire band is 80MHz,

   The third wake-up packet includes a third on signal or a third off signal,

   The fourth wakeup packet includes a fourth on signal or a fourth off signal;

   The third on signal is generated by inserting a third sequence into 13 consecutive subcarriers in the third band and performing the IFFT,

   The fourth on signal is generated by inserting a fourth sequence into 13 consecutive subcarriers in the fourth band and performing the IFFT,

   The length of the third and fourth sequence is 7

   Way.
7. The method of claim 6,

   If the entire band is 80MHz,

   Coefficients of the first sequence are inserted into subcarriers having subcarrier indices of -102, -100, -98, -96, -94, -92, and -90,

   Coefficients of the second sequence are inserted into subcarriers having subcarrier indices of -38, -36, -34, -32, -30, -28, and -26,

   Coefficients of the third sequence are inserted into subcarriers having subcarrier indices of 26, 28, 30, 32, 34, 36, 38,

   The coefficients of the fourth sequence are inserted into subcarriers having subcarrier indices of 90, 92, 94, 96, 98, 100, and 102.

   Way.
8. The method of claim 6,

   If the entire band is 80MHz,

   The first band includes a subcarrier having a subcarrier index of -128 to -65,

   The second band includes a subcarrier having a subcarrier index of -64 to -1,

   The third band includes subcarriers having a subcarrier index of 0 to 63,

   The fourth band includes a subcarrier having a subcarrier index of 64 to 127,

   Subcarrier indices of 13 consecutive subcarriers in the first band are -102 to -90,

   The subcarrier indexes of the 13 consecutive subcarriers in the second band are -38 to -26,

   Subcarrier indices of the 13 consecutive subcarriers in the third band are 26 to 38,

   The subcarrier indexes of the 13 consecutive subcarriers in the fourth band are 64 to 127.

   Way.
9. The method of claim 8,

   If the entire band is 80MHz,

   The IFFT is a 256-point IFFT,

   Coefficients are inserted into a first subcarrier into which the first to fourth sequences are inserted in the entire band.

   0 is inserted into the remaining second subcarriers except the first subcarrier in the entire band.

   Way.
10. The method of claim 9,

    If the entire band is 80MHz,

    0 is inserted in a subcarrier in which the coefficients of the first sequence are not inserted in 13 consecutive subcarriers in the first band,

    0 is inserted in a subcarrier in which the coefficients of the second sequence are not inserted in 13 consecutive subcarriers in the second band,

    0 is inserted in a subcarrier in which the coefficients of the third sequence are not inserted in 13 consecutive subcarriers in the third band,

    Subcarriers in which the coefficients of the fourth sequence are not inserted in 13 consecutive subcarriers in the fourth band are inserted with 0's.

    Way.
11. The method of claim 10,

    If the entire band is 80MHz,

    The first periodic signal generated by inserting the first sequence in 13 consecutive subcarriers in the first band and performing the 256-point IFFT is a 3.2us long signal having a 1.6us long period,

    The first on signal is generated by selecting a 1.6us long signal from the first periodic signal and inserting a first CP.

    The second periodic signal generated by inserting the second sequence in 13 consecutive subcarriers in the second band and performing the 256-point IFFT is a 3.2us long signal having a 1.6us long period,

    The second on signal is generated by selecting a 1.6us long signal from the second periodic signal and inserting a second CP.

    The third periodic signal generated by inserting the third sequence in the 13 consecutive subcarriers in the third band and performing the 256-point IFFT is a 3.2us long signal having a 1.6us long period,

    The third on signal is generated by selecting a signal having a length of 1.6us from the third periodic signal and inserting a third CP.

    The fourth periodic signal generated by inserting the fourth sequence in the 13 consecutive subcarriers in the fourth band and performing the 256-point IFFT is a 3.2us long signal having a 1.6us long period,

    The fourth on signal is generated by selecting a 1.6us long signal from the fourth periodic signal and inserting a fourth CP.

    The length of the first to fourth CP is 0.4us

    Way.
12. The method of claim 1,

    The first data rate is 250 Kbps,

    The second data rate is 62.5 Kbps

    Way.
13. A transmitter for transmitting a wake-up packet in a wireless LAN system,

    A transceiver for transmitting or receiving a wireless signal; And

    A processor for controlling the transceiver, the processor comprising:

    Generate a first wakeup packet having a first data rate and a second wakeup packet having a second data rate; And

    Transmitting the first wakeup packet through a first band and transmitting the second wakeup packet through a second band,

    On-Off Keying (OOK) is applied to the first and second wake-up packets.

    The first wakeup packet includes a first on signal or a first off signal.

    The second wake-up packet includes a second on signal or a second off signal,

    The first on signal is generated by inserting a first sequence into 13 consecutive subcarriers in the first band and performing an Inverse Fast Fourier Transform (IFFT).

    The second on signal is generated by inserting a second sequence into 13 consecutive subcarriers in the second band and performing the IFFT,

    The length of the first and second sequences is 7,

    When the total band is 40 MHz, the first band is the first 20 MHz of the 40 MHz, and the second band is the second 20 MHz of the 40 MHz,

    Coefficients of the first sequence are inserted into subcarriers having subcarrier indices of -38, -36, -34, -32, -30, -28, -26, and

    The coefficients of the second sequence are inserted into subcarriers with subcarrier indices of 26, 28, 30, 32, 34, 36, 38.

    Transmitter.
14. The method of claim 13,

    The first band includes a subcarrier having a subcarrier index of -64 to -1,

    The second band includes subcarriers having a subcarrier index of 0 to 63,

    Subcarrier indices of 13 consecutive subcarriers in the first band are -38 to -26,

    The subcarrier indexes of the 13 consecutive subcarriers in the second band are 26 to 38.

    Transmitter.
15. The method of claim 14,

    The IFFT is a 128-point IFFT,

    Coefficients are inserted into a first subcarrier into which the first to second sequences are inserted in the entire band.

    0 is inserted into the remaining second subcarriers except the first subcarrier in the entire band.

    Transmitter.
16. The method of claim 13,

    0 is inserted in a subcarrier in which the coefficients of the first sequence are not inserted in 13 consecutive subcarriers in the first band,

    0 is inserted in a subcarrier in which the coefficients of the second sequence are not inserted in 13 consecutive subcarriers in the second band,

    The first periodic signal generated by inserting the first sequence in 13 consecutive subcarriers in the first band and performing the 128-point IFFT is a 3.2us long signal having a 1.6us long period,

    The first on signal is generated by selecting a 1.6us length signal from the first periodic signal and inserting a first cyclic prefix (CP).

    The second periodic signal generated by inserting the second sequence in 13 consecutive subcarriers in the second band and performing the 128-point IFFT is a 3.2us long signal having a 1.6us long period,

    The second on signal is generated by selecting a 1.6us long signal from the second periodic signal and inserting a second CP.

    The length of the first and second CP is 0.4us

    Transmitter.
17. In a method for receiving a wake-up packet in a wireless LAN system,

    Receiving, by the receiving device, a first wakeup packet having a first data rate and a second wakeup packet having a second data rate; And

    Decoding, by the receiver, the first wakeup packet or the second wakeup packet for a band supported by the receiver;

    On-Off Keying (OOK) is applied to the first and second wake-up packets.

    The first wakeup packet includes a first on signal or a first off signal.

    The second wake-up packet includes a second on signal or a second off signal,

    The first on signal is generated by inserting a first sequence into 13 consecutive subcarriers in the first band and performing an Inverse Fast Fourier Transform (IFFT).

    The second on signal is generated by inserting a second sequence into 13 consecutive subcarriers in the second band and performing the IFFT,

    The length of the first and second sequences is 7,

    When the total band is 40 MHz, the first band is the first 20 MHz of the 40 MHz, and the second band is the second 20 MHz of the 40 MHz,

    Coefficients of the first sequence are inserted into subcarriers having subcarrier indices of -38, -36, -34, -32, -30, -28, -26, and

    The coefficients of the second sequence are inserted into subcarriers with subcarrier indices of 26, 28, 30, 32, 34, 36, 38.

    Way.

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