WO2018182131A1 - Method for transmitting packet in wireless lan system and wireless terminal using same - Google Patents

Abstract

A method for transmitting a packet for a WUR terminal in a wireless LAN system, according to one embodiment of the present invention, comprises the steps of: transmitting, to a WUR terminal, via an AP, a WUR measurement notification packet for determining the transmission speed of a wake-up packet indicating a main radio module to enter an activated state; sequentially transmitting, via the AP, a plurality of WUR measurement packets when a first acknowledgement packet is received from the WUR terminal as a response to the WUR measurement notification packet, wherein each of the plurality of WUR measurement packets include a payload modulated according to an OOK(on-off keying) method for an WUR module; and receiving, from the WUR terminal, via the AP, a WUR measurement result packet including measurement data for the plurality of WUR measurement packets, wherein the WUR measurement notification packet includes information on the number of the plurality of WUR measurement packets, and information on a measurement interval assigned for the plurality of WUR measurement packets.

Description

Method for transmitting packet in WLAN system and wireless terminal using same

The present disclosure relates to wireless communication, and more particularly, to a method for transmitting a packet in a WLAN system and a wireless terminal using the same.

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. aim to improve performance in real indoor and outdoor environments, such as environments with interference sources, dense heterogeneous network environments, and environments with 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 next-generation WLANs, we are interested in scenarios such as wireless office, smart-home, stadium, hot spot, building / apartment and based on the scenario. As a result, there is a discussion about improving system performance in a dense environment with many APs and 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.

An object of the present specification is to provide a method for transmitting a packet in a WLAN system and a wireless terminal using the same for improved power efficiency.

The present specification relates to a method for transmitting a packet for a WUR terminal in a WLAN system. According to one embodiment, the step of transmitting, by the AP, the WUR measurement notification packet to the WUR terminal to determine the transmission rate of the wake-up packet instructing the main radio module to enter the active state; When the first acknowledgment packet is received from the WUR terminal in response to the WUR measurement notification packet, the AP sequentially transmits a plurality of WUR measurement packets, wherein each of the plurality of WUR measurement packets is OOK (On-Off) for the WUR module. A payload modulated according to the Keying) technique; Receiving, by the AP, a WUR measurement result packet including measurement information for a plurality of WUR measurement packets from a WUR terminal, wherein the WUR measurement notification packet includes information on the number of the plurality of WUR measurement packets and a plurality of WURs; Contains information about the measurement interval allocated for the measurement packet.

According to an embodiment of the present disclosure, a method for transmitting a packet in a WLAN system and a wireless terminal using the same are provided for improved power efficiency.

1 is a conceptual diagram illustrating a structure of a WLAN system.

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 shows an internal block diagram of a wireless terminal receiving a wakeup packet.

5 is a conceptual diagram illustrating a method for a wireless terminal to receive a wakeup packet and a data packet.

6 shows an example of a format of a wakeup packet.

7 shows a signal waveform of a wakeup packet.

FIG. 8 is a diagram for describing a procedure of determining power consumption according to a ratio of bit values constituting information in a binary sequence form.

9 is a diagram illustrating a design process of a pulse according to the OOK technique.

FIG. 10 is a diagram exemplarily illustrating channelization of a wireless channel for communication based on a 2.4 GHz band in a WLAN system.

FIG. 11 is a conceptual diagram illustrating channelization of a wireless channel for communication based on 5 GHz band in a WLAN system according to an exemplary embodiment.

12 is a conceptual diagram illustrating a wireless channel for a wireless LAN system according to the present embodiment.

13 is a diagram for describing a protection time according to an exemplary embodiment.

14 is a diagram for describing a wakeup notification packet, according to an exemplary embodiment.

15 is a diagram illustrating an example for immediate measurement of a transmission speed for a WUR terminal.

16 is a diagram illustrating an example for clearly measuring a transmission rate for a WUR terminal according to an embodiment of the present invention.

17 and 18 illustrate WUR measurement notification packets according to the present embodiment.

19 is a diagram illustrating a WUR measurement result packet according to the present embodiment.

20 is a diagram illustrating a WUR measurement result packet according to another exemplary embodiment.

21 is a block diagram illustrating a wireless terminal to which an embodiment of the present specification can be applied.

The above-described features and the following detailed description are all exemplary for ease of description and understanding of the present specification. That is, the present specification is not limited to this embodiment and may be embodied in other forms. The following embodiments are merely examples to fully disclose the present specification, and are descriptions to convey the present specification to those skilled in the art. Thus, where there are several methods for implementing the components of the present disclosure, it is necessary to clarify that any of these methods may be implemented in any of the specific or equivalent thereof.

In the present specification, when there is a statement that a configuration includes specific elements, or when a process includes specific steps, it means that other elements or other steps may be further included. That is, the terms used in the present specification are only for describing specific embodiments and are not intended to limit the concept of the present specification. Furthermore, the described examples to aid the understanding of the invention also include their complementary embodiments.

The terminology used herein has the meaning commonly understood by one of ordinary skill in the art to which this specification belongs. Terms commonly used should be interpreted in a consistent sense in the context of the present specification. In addition, terms used in the present specification should not be interpreted in an idealistic or formal sense unless the meaning is clearly defined. Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings.

1 is a conceptual diagram illustrating a structure of a WLAN system. FIG. 1A shows the structure of an infrastructure network of the Institute of Electrical and Electronic Engineers (IEEE) 802.11.

Referring to FIG. 1A, the WLAN system 10 of FIG. 1A may include at least one basic service set (hereinafter, referred to as 'BSS', 100, 105). The BSS is a set of access points (APs) and stations (STAs) that can successfully synchronize and communicate with each other, and is not a concept indicating a specific area.

For example, the first BSS 100 may include a first AP 110 and one first STA 100-1. The second BSS 105 may include a second AP 130 and one or more STAs 105-1, 105-2.

The infrastructure BSS (100, 105) may include at least one STA, AP (110, 130) providing a distribution service (Distribution Service) and a distribution system (DS, 120) connecting a plurality of APs. have.

The distributed system 120 may connect the plurality of BSSs 100 and 105 to implement an extended service set 140 which is an extended service set. The ESS 140 may be used as a term indicating one network to which at least one AP 110 or 130 is connected through the distributed system 120. At least one AP included in one ESS 140 may have the same service set identification (hereinafter, referred to as SSID).

The portal 150 may serve as a bridge for connecting the WLAN network (IEEE 802.11) with another network (for example, 802.X).

In a WLAN having a structure as shown in FIG. 1A, a network between APs 110 and 130 and a network between APs 110 and 130 and STAs 100-1, 105-1, and 105-2 may be implemented. Can be.

1B is a conceptual diagram illustrating an independent BSS. Referring to FIG. 1B, the WLAN system 15 of FIG. 1B performs communication by setting a network between STAs without the APs 110 and 130, unlike FIG. 1A. It may be possible to. A network that performs communication by establishing a network even between STAs without the APs 110 and 130 is defined as an ad-hoc network or an independent basic service set (BSS).

Referring to FIG. 1B, the IBSS 15 is a BSS operating in an ad-hoc mode. Since IBSS does not contain an AP, there is no centralized management entity. Thus, in the IBSS 15, the STAs 150-1, 150-2, 150-3, 155-4, and 155-5 are managed in a distributed manner.

All STAs 150-1, 150-2, 150-3, 155-4, and 155-5 of the IBSS may be mobile STAs, and access to a distributed system is not allowed. All STAs of the IBSS form a self-contained network.

The STA referred to herein includes a 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. As any functional medium, it can broadly be used to mean both an AP and a non-AP Non-AP Station (STA).

The STA referred to herein includes a mobile terminal, a wireless device, a wireless transmit / receive unit (WTRU), a user equipment (UE), and a mobile station (MS). It may also be called various names such as a mobile subscriber unit or simply a user.

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 over a wider bandwidth (eg, 40 MHz, 80 MHz) than the channel bandwidth of 20 MHz may be a structure applying linear scaling to the PPDU structure used in the 20 MHz channel bandwidth.

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.

4 shows an internal block diagram of a wireless terminal receiving a wakeup packet.

Referring to FIG. 4, the WLAN system 400 according to the present embodiment may include a first wireless terminal 410 and a second wireless terminal 420.

The first wireless terminal 410 includes a main radio module 411 associated with the main radio (ie, 802.11) and a module including a low-power wake-up receiver ('LP WUR') (hereinafter, WUR). Module 412. The main radio module 411 may transmit user data or receive user data in an activated state (ie, an ON state).

When there is no data (or packet) to be transmitted by the main radio module 411, the first radio terminal 410 may control the main radio module 411 to enter an inactive state (ie, an OFF state). For example, the main radio module 411 may include a plurality of circuits supporting Wi-Fi, Bluetooth® radio (hereinafter referred to as BT radio) and Bluetooth® Low Energy radio (hereinafter referred to as BLE radio).

According to the related art, a wireless terminal operating based on a power save mode may operate in an active state or a sleep state.

For example, a wireless terminal in an activated state can receive all frames from another wireless terminal. In addition, the wireless terminal in the sleep state may receive a specific type of frame (eg, a beacon frame transmitted periodically) transmitted by another wireless terminal (eg, AP).

It is assumed that the wireless terminal referred to herein can operate the main radio module in an activated state or in an inactive state.

A wireless terminal comprising a main radio module 411 in an inactive state (i.e., in an OFF state) may receive a frame transmitted by another wireless terminal (e.g., AP) until the main radio module is woken up by the WUR module 412. For example, it is not possible to receive an 802.11 type PPDU).

For example, a wireless terminal including the main radio module 411 in an inactive state (ie, in an OFF state) may not receive a beacon frame periodically transmitted by the AP.

That is, it may be understood that the wireless terminal including the main radio module (eg, 411) in the inactive state (ie, the OFF state) according to the present embodiment is in a deep sleep state.

In addition, a wireless terminal that includes a main radio module 411 that is in an active state (ie, in an ON state) may receive a frame (eg, an 802.11 type PPDU) transmitted by another wireless terminal (eg, an AP). have.

In addition, it is assumed that the wireless terminal referred to herein can operate the WUR module in a turn-off state or in a turn-on state.

A wireless terminal that includes a WUR module 412 in a turn-on state can only receive certain types of frames transmitted by other wireless terminals. In this case, a specific type of frame may be understood as a frame modulated by an on-off keying (OOK) modulation scheme described below with reference to FIG. 5.

A wireless terminal that includes a WUR module 412 in a turn-off state cannot receive certain types of frames transmitted by other wireless terminals.

In this specification, to indicate the ON state of a specific module included in the wireless terminal, the terms for the activation state and the turn-on state may be used interchangeably. In the same context, the terms deactivation state and turn-off state may be used interchangeably to indicate an OFF state of a particular module included in the wireless terminal.

The wireless terminal according to the present embodiment may receive a frame (or packet) from another wireless terminal based on the main radio module 411 or the WUR module 412 in an activated state.

The WUR module 412 may be a receiver for waking the main radio module 411. That is, the WUR module 412 may not include a transmitter. The WUR module 412 may remain turned on for a duration in which the main radio module 411 is inactive.

For example, when a wake-up packet (WUP) for the main radio module 411 is received, the first radio terminal 410 may be configured to have a main radio module 411 in an inactive state. It can be controlled to enter the activation state.

The low power wake up receiver (LP WUR) included in the WUR module 412 targets a target power consumption of less than 1 mW in an active state. In addition, low power wake-up receivers may use a narrow bandwidth of less than 5 MHz.

In addition, the power consumption by the low power wake-up receiver may be less than 1 Mw. In addition, the target transmission range of the low power wake-up receiver may be the same as the target transmission range of the existing 802.11.

The second wireless terminal 420 according to the present embodiment may transmit user data based on a main radio (ie, 802.11). The second wireless terminal 420 can transmit a wakeup packet (WUP) for the WUR module 412.

Referring to FIG. 4, the second wireless terminal 420 may not transmit user data or a wakeup packet (WUP) for the first wireless terminal 410. In this case, the main radio module 411 included in the second wireless terminal 420 may be in an inactive state (ie, an OFF state), and the WUR module 412 is in a turn-on state (ie, an ON state). There may be.

5 is a conceptual diagram illustrating a method for a wireless terminal to receive a wakeup packet and a data packet.

4 and 5, the WLAN system 500 according to the present embodiment may include a first wireless terminal 510 corresponding to the receiving terminal and a second wireless terminal 520 corresponding to the transmitting terminal. have. Basic operations of the first wireless terminal 510 of FIG. 5 may be understood through the description of the first wireless terminal 410 of FIG. 4. Similarly, the basic operation of the second wireless terminal 520 of FIG. 5 may be understood through the description of the second wireless terminal 420 of FIG. 4.

Referring to FIG. 5, when the wakeup packet 521 is received by the WUR module 512 in an active state, the WUR module 512 may transmit data to the main radio module 511 after the wakeup packet 521. The wakeup signal 523 may be transmitted to the main radio module 511 to correctly receive the packet 522.

For example, the wakeup signal 523 may be implemented based on primitive information inside the first wireless terminal 510.

For example, when the main radio module 511 receives the wake-up signal 523, all of the plurality of circuits (not shown) supporting Wi-Fi, BT radio, and BLE radio included in the main radio module 511 may be provided. It can be activated or only part of it.

As another example, the actual data included in the wakeup packet 521 may be directly transmitted to a memory block (not shown) of the receiving terminal even if the main radio module 511 is in an inactive state.

As another example, when the wake-up packet 521 includes an IEEE 802.11 MAC frame, the receiving terminal may activate only the MAC processor of the main radio module 511. That is, the receiving terminal may maintain the PHY module of the main radio module 511 in an inactive state. The wakeup packet 521 of FIG. 5 will be described in more detail with reference to the following drawings.

The second wireless terminal 520 can be set to transmit the wakeup packet 521 to the first wireless terminal 510. For example, the second wireless terminal 520 may control the main radio module 511 of the first wireless terminal 510 to enter an activated state (ie, an ON state) according to the wakeup packet 521. .

6 shows an example of a format of a wakeup packet.

1 to 6, the wakeup packet 600 may include one or more legacy preambles 610. For example, the legacy preamble 610 may be modulated according to an existing Orthogonal Frequency Division Multiplexing (OFDM) modulation technique.

In addition, the wakeup packet 600 may include a payload 620 after the legacy preamble 610. For example, payload 620 may be modulated according to a simple modulation scheme (eg, On-Off Keying (OOK) modulation technique). The wakeup packet 600 including the payload may be transmitted based on a relatively small bandwidth.

1 through 6, a second wireless terminal (eg, 520) may be configured to generate and / or transmit wakeup packets 521, 600. The first wireless terminal (eg, 510) can be configured to process the received wakeup packet 521.

The wakeup packet 600 may include a legacy preamble 610 or any other preamble (not shown) defined in the existing IEEE 802.11 standard. The wakeup packet 600 may include one packet symbol 615 after the legacy preamble 610. In addition, the wakeup packet 600 may include a payload 620.

The legacy preamble 610 may be provided for coexistence with the legacy STA. In other words, the legacy preamble 610 may be provided for a third party STA (ie, a STA that does not include an LP-WUR). That is, the legacy preamble 610 may not be decoded by the WUR terminal including the WUR module.

In the legacy preamble 610 for coexistence, an L-SIG field for protecting a packet may be used.

For example, an 802.11 STA may detect a start portion of a packet (ie, a start portion of a wakeup packet) through an L-STF field in the legacy preamble 610. Through the L-SIG field in the legacy preamble 610, the 802.11 STA may know the end portion of the packet (ie, the last portion of the wakeup packet).

In order to reduce false alarm of the 802.11n terminal, a modulated symbol 615 may be added after the L-SIG of FIG. 6. One symbol 615 may be modulated according to a BiPhase Shift Keying (BPSK) technique. One symbol 615 may have a length of 4 us. One symbol 615 may have a 20 MHz bandwidth like a legacy part.

Payload 620 includes a wake-up preamble field 621, a MAC header field 623, a frame body field 625, and a Frame Check Sequence (FCS) field 627. can do.

The wakeup preamble field 621 may include a sequence for identifying the wakeup packet 600. For example, the wakeup preamble field 621 may include a pseudo random noise sequence (PN).

The MAC header field 624 may include address information (or an identifier of a receiving apparatus) indicating a receiving terminal receiving the wakeup packet 600. The frame body field 626 may include other information of the wakeup packet 600.

The frame body 626 may include length information or size information of the payload. Referring to FIG. 6, the length information of the payload may be calculated based on length LENGTH information and MCS information included in the legacy preamble 610.

The FCS field 628 may include a Cyclic Redundancy Check (CRC) value for error correction. For example, the FCS field 628 may include a CRC-8 value or a CRC-16 value for the MAC header field 623 and the frame body 625.

7 shows a signal waveform of a wakeup packet.

Referring to FIG. 7, the wakeup packet 700 may include payloads 722 and 724 modulated based on a legacy preamble (802.11 preamble, 710) and an On-Off Keying (OOK) scheme. That is, the wakeup packet WUP according to the present embodiment may be understood as a form in which a legacy preamble and a new LP-WUR signal waveform coexist.

In the legacy preamble 710 of FIG. 7, the OOK technique may not be applied. As mentioned above, payloads 722 and 724 may be modulated according to the OOK technique. However, the wakeup preamble 722 included in the payloads 722 and 724 may be modulated according to another modulation technique.

For example, it may be assumed that the legacy preamble 710 is transmitted based on a channel band of 20 MHz to which 64 FFTs are applied. In this case, payloads 722 and 724 may be transmitted based on a channel band of about 4.06 MHz.

FIG. 8 is a diagram for describing a procedure of determining power consumption according to a ratio of bit values constituting information in a binary sequence form.

Referring to FIG. 8, information in the form of a binary sequence having '1' or '0' as a bit value may be represented. Communication based on the OOK modulation scheme may be performed based on the bit values of the binary sequence information.

For example, when the light emitting diode is used for visible light communication, when the bit value constituting the binary sequence information is '1', the light emitting diode is turned on, and when the bit value is '0', the light emitting diode is turned off. (off) can be turned off.

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 may be provided. For example, information in the form of a binary sequence having a value of '1001101011' may be provided.

As described above, when the bit value is '1', when the transmitting terminal is turned on and when the bit value is '0', when the transmitting terminal is turned off, 6 bit values of the above 10 bit values are applied. The corresponding symbol is turned on.

Since the wake-up receiver WUR according to the present embodiment is included in the receiving terminal, the transmission power of the transmitting terminal may not be greatly considered. The reason why the OOK technique is used in the present embodiment is because power consumption in the decoding procedure of the received signal is very small.

Until the decoding procedure is performed, there may be no significant difference between the power consumed by the main radio and the power consumed by the WUR. However, as the decoding procedure is performed by the receiving terminal, a large difference may occur between power consumed by the main radio module and power consumed by the WUR module. 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 is a diagram illustrating a design process of a pulse according to the OOK technique.

The wireless terminal according to the present embodiment may use an existing 802.11 OFDM transmitter to generate a pulse according to the OOK technique. The existing 802.11 OFDM transmitter can generate a sequence having 64 bits by applying a 64-point IFFT.

1 to 9, the wireless terminal according to the present embodiment may transmit a payload of a wakeup packet (WUP) modulated according to the OOK technique. The payload (eg, 620 of FIG. 6) according to the present embodiment may be implemented based on an ON time signal and an OFF time signal.

The OOK technique may be applied to the ON time signal included in the payload (eg, 620 of FIG. 6) of the wakeup packet WUP. In this case, the on time signal may be a signal having an actual power value.

Referring to the frequency domain graph 920, the on-time signal included in the payload (eg, 620 of FIG. 6) may be selected from among N1 subcarriers (N1 is a natural number) corresponding to the channel band of the wakeup packet (WUP). It can be obtained by performing IFFT on N2 subcarriers (N2 is a natural number). In addition, a predetermined sequence may be applied to the N2 subcarriers.

For example, the channel band of the wakeup packet WUP may be 20 MHz. The N1 subcarriers may be 64 subcarriers, and the N2 subcarriers may be 13 consecutive subcarriers (921 of FIG. 9). The subcarrier interval applied to the wakeup packet (WUP) may be 312.5 kHz.

The OOK technique may be applied to the OFF time signal included in the payload (eg, 620 of FIG. 6) of the wakeup packet WUP. The off time signal may be a signal that does not have an actual power value. That is, the off time signal may not be considered in the configuration of the wakeup packet WUP.

The on time signal included in the payload (620 of FIG. 6) of the wakeup packet (WUP) is a 1-bit ON signal (ie, a 1-bit ON signal) by the WUR module (eg, 512 of FIG. 5). '1'), i.e., demodulation. Similarly, the off time signal included in the payload may be determined (ie, demodulated) as a 1-bit off signal (ie, '0') by the WUR module (eg, 512 of FIG. 5).

A specific sequence may be preset for the subcarrier set 921 of FIG. 9. In this case, the preset sequence may be a 13-bit sequence. For example, a coefficient corresponding to the DC subcarrier in the 13-bit sequence may be '0', and the remaining coefficients may be set to '1' or '-1'.

Referring to the frequency domain graph 920, the subcarrier set 921 may correspond to a subcarrier having a subcarrier index of '-6' to '+6'.

For example, a coefficient corresponding to a subcarrier whose subcarrier indices are '-6' to '-1' in the 13-bit sequence may be set to '1' or '-1'. A coefficient corresponding to a subcarrier whose subcarrier indices are '1' to '6' in the 13-bit sequence may be set to '1' or '-1'.

For example, a subcarrier whose subcarrier index is '0' in a 13-bit sequence may be nulled. The coefficients of the remaining subcarriers (subcarrier indexes '-32' to '-7' and subcarrier indexes '+7' to '+31') except for the subcarrier set 921 are all set to '0'. Can be.

The subcarrier set 921 corresponding to 13 consecutive subcarriers may be set to have a channel bandwidth of about 4.06 MHz. That is, power by signals may be concentrated at 4.06 MHz in the 20 MHz band for the wakeup packet (WUP).

When the pulse according to the OOK technique is used according to the present embodiment, the power is concentrated in a specific band, so that the signal to noise ratio (SNR) may be increased, and the power consumption for conversion in the AC / DC converter of the receiver may be reduced. There is an advantage that it can. Since the sampling frequency band is reduced to 4.06 MHz, power consumption by the wireless terminal can be reduced.

According to the embodiment of the present invention, an OFDM transmitter of 802.11 may have N2 (e.g., 13 consecutive) subs of N1 (e.g., 64) subcarriers corresponding to the channel band (e.g., 20 MHz band) of the wake-up packet. IFFT (eg, 64-point IFFT) may be performed on the carrier.

In this case, a predetermined sequence may be applied to the N2 subcarriers. Accordingly, one on-signal may be generated in the time domain. One bit information corresponding to one on signal may be transmitted through one symbol.

For example, when a 64-point IFFT is performed, a symbol having a 3.2us length corresponding to the subcarrier set 921 may be generated. In addition, when CP (Cyclic Prefix, 0.8us) is added to a symbol having a 3.2us length corresponding to the subcarrier set 921, one symbol having a total length of 4us as shown in the time domain graph 910 of FIG. Can be generated.

In addition, the OFDM transmitter of 802.11 may not transmit the off signal at all.

According to the present embodiment, a first wireless terminal (eg, 510 of FIG. 5) including a WUR module (eg, 512 of FIG. 5) may receive a packet based on an envelope detector that extracts an envelope of the received signal. Can be demodulated.

For example, the WUR module (eg, 512 of FIG. 5) according to the present embodiment may compare a power level of a received signal obtained through an envelope of the received signal with a preset threshold level.

If the power level of the received signal is higher than the threshold level, the WUR module (eg, 512 of FIG. 5) may determine the received signal as a 1-bit ON signal (ie, '1'). If the power level of the received signal is lower than the threshold level, the WUR module (eg, 512 of FIG. 5) may determine the received signal as a 1-bit OFF signal (ie, '0').

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

Generalizing the contents of FIG. 9, each signal having a length of K (eg, K is a natural number) in the 20 MHz band may be transmitted based on consecutive K subcarriers of 64 subcarriers for the 20 MHz band. For example, K may correspond to the number of subcarriers used to transmit the signal. K may also correspond to the bandwidth of a pulse according to the OOK technique.

All of the coefficients of the remaining subcarriers except K subcarriers among the 64 subcarriers may be set to '0'.

Specifically, for the 1-bit off signal corresponding to '0' (hereinafter, information 0) and the 1-bit on signal corresponding to '1' (hereinafter, information 1), the same K subcarriers may be used. have. For example, the index for the K subcarriers used may be expressed 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).

FIG. 10 is a diagram exemplarily illustrating channelization of a wireless channel for communication based on a 2.4 GHz band in a WLAN system.

Referring to FIG. 10, the horizontal axis of FIG. 10 may represent a frequency (GHz) for the 2.4 GHz band. The vertical axis of FIG. 10 may be associated with the presence of a channel.

In order to support the operation of the wireless terminal according to the present embodiment in the 2.4 GHz band of FIG. 10, the first to thirteenth channels ch # 1 to ch # 13 may be allocated. For example, a bandwidth (BW) for each of the first to thirteenth channels ch # 1 to ch # 13 may be 22 MHz.

The first channel center frequency fc1 for the first channel ch # 1 of FIG. 10 may be 2.412 GHz. For example, the first channel ch # 1 may be defined between 2.401 GHz and 2.423 GHz. In addition, the second channel center frequency fc2 for the second channel ch # 2 may be 2.417 GHz. For example, the second channel ch # 2 may be defined between 2.406 GHz and 2.428 GHz.

The third channel center frequency fc3 for the third channel ch # 3 of FIG. 10 may be 2.422 GHz. For example, the third channel ch # 3 may be defined between 2.411 GHz and 2.433 GHz. In addition, the fourth channel center frequency fc4 for the fourth channel ch # 4 may be 2.427 GHz. For example, the third channel ch # 3 may be defined between 2.416 GHz and 2.438 GHz.

The fifth channel center frequency fc5 for the fifth channel ch # 5 of FIG. 10 may be 2.432 GHz. For example, the fifth channel ch # 5 may be defined between 2.421 GHz and 2.443 GHz. In addition, the sixth channel center frequency fc6 for the sixth channel ch # 6 may be 2.437 GHz. For example, the sixth channel ch # 6 may be defined between 2.426 GHz and 2.448 GHz.

The seventh channel center frequency fc7 for the seventh channel ch # 7 of FIG. 10 may be 2.442 GHz. For example, the seventh channel ch # 7 may be defined between 2.431 GHz and 2.453 GHz. In addition, the eighth channel center frequency fc8 for the eighth channel ch # 8 may be 2.447 GHz. For example, the eighth channel ch # 8 may be defined between 2.436 GHz and 2.458 GHz.

A ninth channel center frequency fc9 for the ninth channel ch # 9 of FIG. 10 may be 2.452 GHz. For example, the ninth channel ch # 9 may be defined between 2.441 GHz and 2.463 GHz. In addition, the tenth channel center frequency fc10 for the tenth channel ch # 10 may be 2.457 GHz. For example, the tenth channel ch # 10 may be defined between 2.446 GHz and 2.468 GHz.

The eleventh channel center frequency fc11 for the eleventh channel ch # 11 of FIG. 10 may be 2.462 GHz. For example, the eleventh channel ch # 11 may be defined between 2.451 GHz and 2.473 GHz. In addition, the twelfth channel center frequency fc12 for the twelfth channel ch # 12 may be 2.467 GHz. For example, the twelfth channel ch # 12 may be defined between 2.456 GHz and 2.478 GHz.

The thirteenth channel center frequency fc13 for the thirteenth channel ch # 13 of FIG. 10 may be 2.472 GHz. For example, the thirteenth channel ch # 13 may be defined between 2.461 GHz and 2.483 GHz. The fourteenth channel center frequency fc14 for the fourteenth channel ch # 14 of FIG. 10 may be 2.482 GHz. For example, the fourteenth channel ch # 14 may be defined between 2.473 GHz and 2.495 GHz.

Referring to FIG. 10, the first channel ch # 1, the sixth channel ch # 6, and the eleventh channel ch # 11 indicated by solid lines may be understood as independent channels that do not overlap each other in the frequency domain. . The channelization scheme of the wireless channel for communication based on the 2.4 GHz band shown in FIG. 10 is just an example, and it will be understood that the present specification is not limited thereto.

FIG. 11 is a conceptual diagram illustrating channelization of a wireless channel for communication based on 5 GHz band in a WLAN system according to an exemplary embodiment. A plurality of channels having 20 MHz, 40 MHz, 80 MHz, and 160 MHz bandwidths are shown to support the operation of the wireless terminal according to the exemplary embodiment in the 5 GHz band.

Referring to FIG. 11, there may be 25 non-overlapping channels having a 20 MHz bandwidth in a 5 GHz band. For example, the 36th channel (ch # 36) having a center frequency of 5.180 GHz, the 40th channel (ch # 40) having a center frequency of 5.200 GHz, and the 44th channel (ch # 44) having a center frequency of 5.220 GHz. ) And channel 48 (ch # 48) having a center frequency of 5.240 GHz.

In addition, channel 52 (ch # 52) having a center frequency of 5.260 GHz, Channel 56 (ch # 56) having a center frequency of 5.280 GHz, Channel 60 (ch # 60) having a center frequency of 5.300 GHz, and There may be channel 64 (ch # 64) having a center frequency of 5.320 GHz.

In addition, channel 100 (ch # 100) having a center frequency of 5.500 GHz, Channel 104 (ch # 104) having a center frequency of 5.520 GHz, Channel 108 (ch # 108) having a center frequency of 5.540 GHz, Channel 112 (ch # 112) with a center frequency of 5.560 GHz, Channel 116 (ch # 116) with a center frequency of 5.580 GHz, Channel 120 (ch # 120) of a center frequency of 5.600 GHz, and center frequency There may be channel 124 (ch # 124) having a value of 5.620 GHz.

In addition, channel 128 (ch # 128) having a center frequency of 5.640 GHz, Channel 132 (ch # 104) having a center frequency of 5.660 GHz, Channel 136 (ch # 136) having a center frequency of 5.680 GHz, There may be channel 140 (ch # 140) having a center frequency of 5.700 GHz and channel 144 (ch # 144) having a center frequency of 5.720 GHz.

In addition, channel 149 (ch # 149) having a center frequency of 5.745 GHz, Channel 153 (ch # 153) having a center frequency of 5.765 GHz, Channel 157 (ch # 157) having a center frequency of 5.785 GHz, There may be channel 161 (ch # 161) having a center frequency of 5.805 GHz and channel 165 (ch # 165) having a center frequency of 5.825 GHz.

Referring to FIG. 11, there may be 12 non-overlapping channels having a 40 MHz bandwidth based on channel bonding in a 5 GHz band. In addition, there may be six non-overlapping channels having an 80 MHz bandwidth based on channel bonding in the 5 GHz band. In addition, there may be two non-overlapping channels having a 160 MHz bandwidth based on channel bonding in the 5 GHz band.

The channelization scheme of the wireless channel for 5GHz band-based communication shown in FIG. 11 is just an example, and it will be understood that the present specification is not limited thereto.

12 is a conceptual diagram illustrating a wireless channel for a wireless LAN system according to the present embodiment. The wireless channel 1210 of FIG. 12 may be understood as a 20 MHz channel preset by the AP.

For example, the wireless channel 1210 may correspond to any one 20 MHz channel belonging to the 2.4 GHz band of FIG. 10. Alternatively, the wireless channel 1210 may correspond to any one 20 MHz channel belonging to the 5 GHz band of FIG. 11.

For example, wireless channel 1210 may correspond to a primary 20 MHz channel. The wireless terminal may detect the start of a packet (eg, PPDU) to be received by the wireless terminal based on a primary 20 MHz channel. The wireless terminal may determine the state of the wireless channel (eg, idle state or busy state) based on the primary 20 MHz channel.

For clarity and brevity, it may be assumed that the radio channel 1210 corresponds to 64 subcarriers shown in the frequency domain graph 920 of FIG. 9.

According to the above assumption, the plurality of subchannels 1211, 1212, and 1213 may be formed based on 64 subcarriers for the wireless channel 1210.

For example, the first subchannel 1211 may be formed based on a contiguous N1 (eg, 13) first subcarrier set among the 64 subcarriers illustrated in the frequency domain graph 920 of FIG. 9. Can be.

For example, the second subchannel 1212 may be formed based on a contiguous N2 (eg, 13) second subcarrier set among the 64 subcarriers shown in the frequency domain graph 920 of FIG. 9. Can be.

For example, the third subchannel 1213 may be formed based on a contiguous N3 (eg, 13) third subcarrier set among the 64 subcarriers illustrated in FIG. 9.

For example, the N1 first subcarrier set and the N2 second subcarrier set may not overlap each other. For example, the N2 second subcarrier set and the N3 third subcarrier set may not overlap each other. For example, the N3 third subcarrier set and the N1 first subcarrier set may not overlap each other.

13 is a diagram for describing a protection time according to an exemplary embodiment.

Referring to FIG. 13, the horizontal axis of the access point 1300 may represent a time ta, and the vertical axis may be associated with the existence of a frame to be transmitted by the AP 1300.

The WUR terminal 1310 may include a main radio module 1311 and a WUR module 1312. For example, the main radio module 1311 of FIG. 13 may correspond to the main radio module 511 of FIG. 5. The WUR module 1312 of FIG. 13 may correspond to the WUR module 512 of FIG. 5.

The horizontal axis of the main radio module 1311 may represent time tm. In addition, an arrow displayed at the lower end of the horizontal axis of the main radio module 1311 may indicate a power state (eg, an ON state or an OFF state) of the main radio module 1311. The vertical axis of the main radio module 1311 may be associated with the presence of a frame to be transmitted by the main radio module 1311.

The horizontal axis of the WUR module 1312 may represent time tw. In addition, an arrow displayed at the bottom of the horizontal axis of the WUR module 1312 may indicate a power state (eg, an ON state or an OFF state) of the WUR module 1312. The vertical axis of the WUR module 1312 may be associated with the presence of a frame to be transmitted by the WUR module 1312.

Hereinafter, the WUR terminal 1310 may be assumed to be a wireless terminal combined with the AP 1300 through a combining procedure. In addition, it may be assumed that the main radio module 1311 of the WUR terminal 1310 of FIG. 13 is in an inactive state (ie, an OFF state), and the WUR module 1312 is in a turn-on state (ie, an ON state). have.

In the first period T1 to T2 of FIG. 13, the AP 1300 may transmit a wake-up packet (WUP).

For example, the wakeup packet (WUP) may be transmitted according to a unicast technique. That is, the wakeup packet WUP of FIG. 13 may indicate that the main radio module 1311 of the WUR terminal 1310 enters an activated state.

The wakeup packet WUP of FIG. 13 may include a payload modulated according to an on-off keying (OOK) technique for the WUR module 1312. For example, the payload is an ON signal determined as a 1 bit ON signal by the WUR module 1312 and an OFF signal determined as a 1 bit OFF signal by the WUR module 1312. Can be implemented based on (OFF signal).

In addition, the ON signal included in the payload performs an Inverse Fast Fourier Transform (IFFT) on N2 subcarriers of the N1 subcarriers corresponding to the channel band (eg, 20 MHz) of the wakeup packet (WUP). Can be obtained. For example, a predetermined sequence may be applied to the N2 subcarriers. Here, N1 and N2 may be natural numbers.

The guard time according to the wakeup packet WUP may be understood as the second periods T2 to T3 of FIG. 13. In this case, the second sections T2 to T3 of FIG. 13 may be determined according to a parameter preset for the guard time.

Until the second period T2 to T3 of FIG. 13 corresponding to the guard time elapses, the AP 1300 may wait without transmitting a downlink packet for the WUR terminal 1310.

For example, the predetermined parameter for the guard time may be a value individually set in the combining procedure of the AP 1300 and the WUR terminal (eg, 1310). Until the second period T2 to T3 corresponding to the guard time elapses, the AP 1300 buffers a downlink packet for the WUR terminal (eg, 1310) in a transmission queue (not shown) of the AP 1300. can do.

It may be assumed that the wakeup packet (WUP) of FIG. 13 is successfully received based on the WUR module 1312 of the WUR terminal (eg, 1310).

According to the above assumption, in the second period T2 to T3 of FIG. 13, the WUR terminal 1310 may transmit a wakeup signal (not shown) to the main radio module 1311. The wakeup signal may be understood as internal primitive information of the WUR terminal 1310 for entering the main radio module 1311 into an activated state (ie, an ON state).

The time taken for the main radio module 1311 to enter the activated state (ie, the ON state) according to the wake-up signal may be understood as a turn-on delay (TOD).

When the turn-on delay TOD of the main radio module 1311 elapses, the main radio module 1311 may enter an active state (ie, an ON state). Subsequently, the WUR terminal 1310 may control the main radio module 1311 to maintain an activated state (that is, an ON state) until the second point T2 to T3 ends.

In addition, at a time point T2 when the second period T2 to T3 of FIG. 13 is entered, the WUR terminal 1310 may control the WUR module 1312 to enter a turn-off state (that is, an OFF state). have. Subsequently, the WUR terminal 1310 may control the WUR module 1312 to maintain a turn-off state (that is, an OFF state) until a time point T3 when the second period T2 to T3 ends.

For reference, there may be a turn-off delay (not shown) for entering the WUR module 1312 into the turn-off state. However, the turn-off delay may be a relatively small value compared to the turn-on delay (TOD).

14 is a diagram for describing a wakeup notification packet, according to an exemplary embodiment. Referring to FIGS. 13 and 14, the AP 1400 of FIG. 14 may correspond to the AP 1300 of FIG. 13. The WUR terminal 1410 of FIG. 14 may correspond to the WUR terminal 1310 of FIG. 13.

According to an embodiment of FIG. 14, a wake-up notification packet (WNP) may be introduced to replace the guard time of FIG. 13.

In the first period T1 to T2 of FIG. 14, the AP 1400 may transmit a wakeup packet WUP. The description of the wakeup packet WUP of FIG. 14 may be replaced with the description of the wakeup packet WUP described with reference to FIG. 13.

It may be assumed that the wakeup packet WUP of FIG. 14 is successfully received based on the WUR module 1412 of the WUR terminal (eg, 1410).

When the turn-on delay TOD of the main radio module 1411 elapses, the main radio module 1411 may enter an activated state (ie, an ON state). Subsequently, the WUR terminal 1410 may control the main radio module 1411 to maintain an activated state (that is, an ON state) until the second point T2 to T3 ends.

In addition, at a time point T2 when the second period T2 to T3 of FIG. 14 is entered, the WUR terminal 1410 may control the WUR module 1412 to enter a turn-off state (that is, an OFF state). have. Subsequently, the WUR terminal 1410 may control the WUR module 1412 to maintain a turn-off state (that is, an OFF state) until the second time period T2 to T3 ends.

After the main radio module 1411 enters the active state (ie, the ON state), the WUR terminal 1410 notifies the wakeup of the main radio module 1411 to enter the activated state (ie, the ON state). The packet WNP can be transmitted.

For example, the wakeup notification packet WNP may be transmitted based on the main radio module 1411. In addition, the wakeup notification packet (WNP) may be understood as a frame transmitted on a contention basis for a wireless channel.

Subsequently, the AP 1400 may transmit the first acknowledgment packet ACK # 1 in response to the wakeup notification packet WNP. That is, when a predetermined time elapses after the reception of the wakeup notification packet WNP, the first acknowledgment packet ACK # 1 may be transmitted. For example, the predetermined time may be SIFS.

After successful reception of the wake-up notification packet (WNP), the AP 1400 may transmit a downlink packet (DL PPDU) for the WUR terminal 1410 on a contention basis for a wireless channel.

Subsequently, the AP 1400 may receive the second acknowledgment packet ACK # 2 in response to the downlink packet DL PPDU. That is, when a predetermined time has passed since the transmission of the downlink packet DL PPDU, the second acknowledgment packet ACK # 2 may be received. For example, the predetermined time may be SIFS.

The wakeup packet (WUP) mentioned herein may be transmitted based on various transmission rates. In this case, since there is no ACK for the wakeup packet (WUP), the AP cannot know whether the transmission rate currently set in the wakeup packet (WUP) is appropriate.

Hereinafter, the AP requests the WUR terminal for information for determining the transmission rate of the wakeup packet (WUP), and the WUR terminal reports the information associated with the wakeup packet (WUP) to the AP in response to the request of the AP. Various embodiments are described.

In the present specification, the WUR terminal may perform a reception operation and a demodulation operation on the wakeup packet WUP based on the information on the transmission rate of the wakeup packet WUP. There may be two or more types of transmission rates of the wakeup packet (WUP).

As described above, since there is no ACK frame for the wakeup packet (WUP), it may be difficult for the AP to determine whether the transmission rate of the wakeup packet (WUP) is appropriate for the current channel state.

Hereinafter, in order to determine the transmission rate of the wakeup packet (WUP), the AP requests information from the WUR terminal for determining the transmission rate of the wakeup packet (WUP), and the WUR terminal informs the AP of the requested information. An embodiment of the process is described.

15 is a diagram illustrating an example for immediate measurement of a transmission rate for a WUR terminal.

Referring to FIG. 15, the AP 1500 of FIG. 15 may correspond to the AP 520 of FIG. 5. Referring to FIG. 15, the horizontal axis of the access point 1500 may represent a time ta, and the vertical axis may be associated with the existence of a frame to be transmitted by the AP 1500.

The WUR terminal 1510 of FIG. 15 may correspond to the WUR terminal 510 of FIG. 5. The WUR terminal 1510 may include a main radio module 1511 and a WUR module 1512. For example, the main radio module 1511 of FIG. 15 may correspond to the main radio module 511 of FIG. 5. The WUR module 1512 of FIG. 15 may correspond to the WUR module 512 of FIG. 5.

The horizontal axis of the main radio module 1511 may represent time tm. In addition, an arrow displayed at the lower end of the horizontal axis of the main radio module 1511 may indicate a power state (eg, an ON state or an OFF state) of the main radio module 1511. The vertical axis of the main radio module 1511 may be associated with the presence of a frame to be transmitted by the main radio module 1511.

The horizontal axis of the WUR module 1512 may represent time tw. In addition, an arrow displayed at the bottom of the horizontal axis of the WUR module 1512 may indicate a power state (eg, an ON state or an OFF state) of the WUR module 1512. The vertical axis of the WUR module 1512 may be associated with the presence of a frame to be transmitted by the WUR module 1512.

Hereinafter, the WUR terminal 1510 may be assumed to be a wireless terminal combined with the AP 1500 through a combining procedure. In addition, it may be assumed that the main radio module 1311 of the WUR terminal 1510 of FIG. 15 is in an active state (ie, an ON state), and the WUR module 1512 is in a turn-off state (ie, an OFF state). have.

In the first period T1 to T2 of FIG. 15, the AP 1500 may transmit a WUR measurement notification packet for measuring a transmission speed of the WUR terminal 1510 to the WUR terminal.

In this case, the WUR measurement notification packet may be received based on the main radio module 1511 of the WUR terminal 1510. That is, the WUR measurement notification packet may be understood as a packet modulated according to an orthogonal frequency division multiplexing (OFDM) technique.

Subsequently, the WUR terminal 1510 may transmit a first acknowledgment packet ACK # 1 indicating the successful reception of the WUR measurement notification packet to the AP 1500. In this case, the first acknowledgment packet ACK # 1 may be transmitted based on the main radio module 1511 in the activated state (ie, the ON state) of the WUR terminal 1510.

Subsequently, the WUR terminal 1510 may transmit a WUR measurement result packet including measurement information associated with the wakeup packet (WUP) to the AP 1500. For example, the measurement information may be understood as information measured by the WUR terminal 1510 based on a wakeup packet (WUP, not shown) previously received by the WUR terminal 1510.

Subsequently, the AP 1500 may transmit a second acknowledgment packet ACK # 2 indicating a successful reception of the WUR measurement result packet to the WUR terminal 1510.

16 is a diagram illustrating an example for explicit measurement of a transmission rate for a WUR terminal according to an embodiment of the present invention.

1 to 16, in the first period T1 to T2 of FIG. 16, the WUR terminal 1610 may control the main radio module 1611 to maintain an active state (that is, an ON state). . In addition, the WUR terminal 1610 may control the WUR module 1612 to maintain a turn-off state (that is, an OFF state).

In the first period T1 to T2 of FIG. 16, in order to obtain measurement information for determining a transmission rate of a wakeup packet (WUP) to be transmitted to the WUR terminal 1610 based on the WUR module 1612, the AP The 1600 may transmit a WUR Measurement Notification (hereinafter, referred to as WUR MN) packet to the WUR terminal 1610.

For example, a WUR MN packet may include information about the number of WUR measurement packets to be transmitted (eg, four) and a plurality of WUR measurements to obtain measurement information for determining a transmission speed. It may include information on the measurement interval (for example, T2 to T3 of FIG. 16) allocated for the packet.

For example, the WUR MN packet may be a packet modulated according to an orthogonal frequency division multiplexing (OFDM) technique. The WUR MN packet is described in more detail with reference to the accompanying drawings.

For clarity and concise description of FIG. 16, it may be assumed that the WUR MN packet is successfully received based on the main radio module 1611 of the WUR terminal 1610.

Accordingly, the WUR terminal 1610 may determine the number of WUR measurement packets (for example, 4) and the allocated measurement for the plurality of WUR measurement packets based on the received WUR measurement notification (WUR MN) packet. Information about a section (for example, T2 to T3 of FIG. 16) may be obtained.

A first acknowledgment packet (ACK # 1) indicating successful reception of a WUR MN packet may be received from the WUR terminal 1610.

After transmission of the first acknowledgment packet ACK # 1, the WUR terminal 1610 may control the main radio module 1611 to enter an inactive state (ie, an OFF state). In addition, after the transmission of the first acknowledgment packet ACK # 1, the WUR terminal 1610 may control the WUR module 1612 to enter a turn-on state (ie, an ON state).

At the time point T2 at which the second period T2 to T3 of FIG. 16 enters (ie, after ACK # 1 is received), the WUR terminal 1610 is deactivated (ie, OFF) of the main radio module 1611. State). Subsequently, the WUR terminal 1610 may control the main radio module 1611 to maintain an inactive state (that is, an OFF state) until a time point T3 at which the second sections T2 to T3 of FIG. 16 pass. .

In addition, at a time point T2 when entering the second section T2 to T3 of FIG. 16 (that is, after ACK # 1 is received), the WUR terminal 1610 may turn on the WUR module 1612 (ie, In this case, the WUR terminal 1610 is turned on by the WUR module 1612 until a time point T3 at which the second section T2 to T3 of FIG. 16 passes. (That is, ON state) can be controlled.

The second periods T2 to T3 of FIG. 16 may be referred to as measurement periods for determining a transmission speed of the wakeup packet WUP.

In the second period T2 to T3 of FIG. 16, the AP 1600 may sequentially transmit a plurality of WUR Measurement Packets (WUP # m). For example, the AP 1600 may sequentially transmit the first to fourth WUR measurement packets WUP # m1 to WUP # m4.

In other words, each of the plurality of WUR measurement packets (eg, WUP # m1 to WUP # m4) may be understood as a packet used to measure a state of a wireless channel for transmission of a wakeup packet (WUP).

For example, each of the plurality of WUR measurement packets (eg, WUP # m1 to WUP # m4) includes a payload modulated according to the On-Off Keying (OOK) technique for the WUR module 1612. can do. For example, each of the plurality of WUR measurement packets (eg, WUP # m1 to WUP # m4) may be a packet including the same information as the wakeup packet 600 of FIG. 6.

Each of the plurality of WUR measurement packets (eg, WUP # m1 to WUP # m4) of FIG. 16 may be transmitted based on the same type of transmission rate determined by the AP.

In addition, on the premise that there are various types of transmission rates that can be transmitted by the AP (for example, four types), the plurality of WUR measurement packets (for example, WUP # m1 to WUP # m4) may be the first type to the first. It can be transmitted based on four types of transmission rates.

For example, the first WUR measurement packet may be transmitted based on the first type of transmission rate. The second WUR measurement packet may be transmitted based on the second type of transmission rate. The third WUR measurement packet may be transmitted based on the third type of transmission rate. The fourth WUR measurement packet may be transmitted based on the fourth type of transmission rate. At the time point T3 when the third period T3 to T4 of FIG. 16 enters (that is, the measurement interval for the WUR measurement packet is When elapsed), the WUR terminal 1610 may control the main radio module 1611 to enter an activated state (ie, an ON state).

In addition, at the time T3 when entering the third section T3 to T4 of FIG. 16 (that is, when the measuring section for the WUR measurement packet elapses), the WUR terminal 1610 is turned on by the WUR module 1612. Control to enter the off state (ie, OFF state).

In the third section T3 to T4 of FIG. 16, the WUR terminal 1610 is measured by the WUR terminal 1610 based on each of a plurality of WUR measurement packets (eg, WUP # m1 to WUP # m4). A WUR Measurement Result (WUR MR) packet including measurement information may be transmitted.

For example, the measurement information is received by the WUR terminal 1610 during a measurement interval (for example, T2 to T3 of FIG. 16) of a plurality of WUR measurement packets (eg, WUP # m1 to WUP # m4 of FIG. 16). Information on the number of packets, a packet error rate (PER) value for a plurality of WUR measurement packets (e.g., WUP # m1 to WUP # m4 in FIG. 16), and a plurality of WUR measurement packets (e.g., WUP # m1 in FIG. Signal-to-Interference-plus-Noise Ratio (SINR) value for ˜WUP # m4) may be included.

For example, the WUR MR packet may be a packet modulated according to an orthogonal frequency division multiplexing (OFDM) technique. The WUR MR result packet will be described in more detail with reference to the accompanying drawings.

For clarity and concise description of FIG. 16, it may be assumed that a WUR measurement result (WUR MR) packet is successfully received at the AP 1600. Subsequently, the AP 1600 may transmit a second acknowledgment packet ACK # 2 indicating successful reception of the WUR MR packet to the WUR terminal 1610.

Although not shown in FIG. 16, the AP 1600 may determine a transmission rate for the wakeup packet WUP based on measurement information included in the WUR MR packet. Subsequently, the AP 1600 may transmit the wakeup packet WUP using the determined transmission rate.

For example, in the second period T2 to T3 of FIG. 16, each WUR measurement packet (eg, WUP # m1 to WUP # m4) may be transmitted based on the first type transmission rate determined by the AP. Can be.

In this case, the information included in the measurement information may indicate that the first type of transmission speed is not appropriate (for example, when there are few packets received). To determine the transmission rate of the wakeup packet (WUP), the AP may transmit a plurality of subsequent measurement packets (not shown) based on different types of transmission rates in a next measurement interval (not shown).

As another example, in the second period T2 to T3 of FIG. 16, a transmission rate may be set differently for each WUR measurement packet (eg, WUP # m1 to WUP # m4). In this case, the AP may select the most appropriate type of transmission rate based on the information included in the measurement information.

17 and 18 illustrate WUR measurement notification packets according to the present embodiment.

Referring to FIG. 17, a WUR MN packet 1700 may include a plurality of fields 1710 ˜ 1760.

The measurement type field 1710 may include an indicator for determining the type of the measurement operation of the WUR terminal. For example, to operate the WUR terminal according to the embodiment of FIG. 15, the AP may set a value corresponding to '0' in the indicator of the measurement type field 1710.

If a value corresponding to '0' is set in the indicator of the measurement type field 1710, the AP may acquire the remaining fields 1720 ˜ of the WUR measurement notification (WUR MN) packet 1700 in order to obtain a measurement result previously stored in the WUR terminal. 1760).

That is, in response to a WUR measurement notification (WUR MN) packet in which a value corresponding to '0' is set in the indicator of the measurement type field 1710, the WUR terminal sends a separate WUR measurement packet (for example, WUP # m1 of FIG. 16). Measurement information associated with the wake-up packet WUP received at the WUR terminal may be transmitted to the AP without the measurement operation for ˜WUP # m4).

The measurement information associated with the wakeup packet WUP received at the WUR terminal may be a value previously stored in the WUR terminal.

For clarity of FIG. 17, the wakeup packet WUP received at the WUR terminal may be understood as a wakeup packet WUP received at the WUR terminal immediately before the reception of the WUR measurement notification (WUR MN) packet. .

Alternatively, the wakeup packet WUP received at the WUR terminal may include the full wakeup packet or the full wakeup packet received by the AP after the WUR terminal is combined with the AP until the reception of the WUR MN packet. It can be understood as part.

The WUR channel field 1720 may be used to request channel information (or resource unit) associated with a wakeup packet (WUP) received from the WUR terminal.

For example, in order to request the WUR terminal to request a measurement result for the wakeup packet WUP received on all channels (eg, 1211, 1212, 1213 of FIG. 12), the AP may request a WUR channel field 1720. You can set the value corresponding to '0'.

As another example, in order to request a WUR terminal for a measurement result for a wakeup packet (WUP) received on a specific channel (eg, 1213), the AP corresponds to a value corresponding to '3' in the WUR channel field 1720. Can be set.

The measured WUR Packet PER request field 1730 may be used to request a packet error rate (PER) value for a wakeup packet (WUP) received from the WUR terminal.

The measurement WUP packet PER request field 1730 may be used to request a PER value for the wakeup packet WUP received from the WUR terminal.

The Number of Received WUR Packet request field 1740 indicates information on the number of wakeup packets (WUP) successfully received by the WUR terminal after performing a combining procedure with the WUR terminal and the AP. It can be used to request the terminal.

The SINR request field 1750 of the received WUR packet may be used to request the WUR terminal for a Signal-to-Interference-plus-Noise Ratio (SINR) value for the wakeup packet WUP received at the WUR terminal. .

The time request field 1760 of the received WUR packet may be used to request the WUR terminal for information on the reception time of the wakeup packet WUP received at the WUR terminal.

Referring to FIG. 18, a WUR measurement notification (WUR MN) packet 1800 may include a plurality of fields 1810-1870.

The measurement type field 1810 may include an indicator for determining the type of the measurement operation of the WUR terminal. That is, in order to notify the WUR terminal of the transmission of the plurality of WUR measurement packets in advance, the AP may set a value corresponding to '1' in the indicator of the measurement type field 1810.

The AP acquires measurement results for a plurality of WUR measurement packets (eg, WUP # m1 to WUP # m4 of FIG. 16) to be sequentially transmitted, and the remaining fields 1820 to 1200 of the WUR measurement notification (WUR MN) packet 1800. 1870 may be configured.

That is, a plurality of WUR measurement packets (eg, WUP # m1 to WUP # m4 of FIG. 16) are samples for obtaining measurement results necessary for determining an optimal transmission rate of a wakeup packet (WUP) to be transmitted to a WUR terminal. Can be understood as a packet.

In other words, the WUR terminal receiving the WUR MN packet may perform a measurement operation on a plurality of WUR measurement packets (eg, WUP # m1 to WUP # m4 of FIG. 16). Subsequently, the WUR terminal may transmit the measurement result obtained through the measurement operation to the AP.

The WUR channel field 1820 is used to inform the WUR terminal of channel information (or resource unit) to which a plurality of WUR measurement packets (eg, WUP # m1 to WUP # m4 of FIG. 16) are sequentially transmitted. Can be.

For example, if a value corresponding to '3' is set in the WUR channel field 1820, the AP transmits a plurality of WUR measurement packets (eg, WUP # m1 to FIG. 16) through a specific channel (eg, 1213). The WUR terminal may be notified in advance that the WUP # m4) will be sequentially transmitted.

The measurement start time field 1830 may be used to inform the WUR terminal of information on a start time at which transmission of a plurality of WUR measurement packets (eg, WUP # m1 to WUP # m4 of FIG. 16) will start. have.

For example, the first time WUR measurement packet (WUP # m1, that is, the first wake-up packet transmitted) among a plurality of WUR measurement packets (for example, WUP # m1 to WUP # m4 in FIG. 16) may be transmitted. information about the start time may be included in the measurement start time field 1830.

The measurement end time field 1840 is configured to complete transmission of a fourth WUR measurement packet (WUP # m4, the latest wake-up packet) among a plurality of WUR measurement packets (for example, WUP # m1 to WUP # m4 in FIG. 16). Information about an end time to be used may be used to inform the WUR terminal of the inclusion.

The measurement duration field 1850 informs the WUR terminal about the duration of the measurement interval (for example, T2 to T3 of FIG. 16) for a plurality of WUR measurement packets (for example, WUP # m1 to WUP # m4 of FIG. 16). Can be used to give

The transmission number field 1860 of the WUR packet may be used to inform the WUR terminal of information (for example, four) about the number of WUR measurement packets to be transmitted in the measurement interval (for example, T2 to T3 of FIG. 16). Can be.

The WUR rate field 1870 is a WUR terminal that transmits information on transmission rates of a plurality of WUR measurement packets (eg, WUP # m1 to WUP # m4 of FIG. 16) to be transmitted in a measurement interval (for example, T2 to T3 of FIG. 16). Can be used to inform.

19 is a diagram illustrating a WUR measurement result packet according to the present embodiment.

15 to 19, the WUR terminal (ie, 1510, 1610) may transmit a WUR measurement result packet 1900 according to an indicator of a measurement type field (ie, 1710, 1810) of a WUR measurement notification packet received at the WUR terminal. ) Can be configured.

In the first case, when the indicator of the measurement type field (ie, 1710, 1810) of the WUR measurement notification packet is set to a value corresponding to '0' (that is, as shown in FIG. 15, a plurality of WUR measurement packets (eg, FIG. 16). WUP # m1 to WUP # m4) are not transmitted), the WUR terminal may configure the WUR measurement result packet 1900 based on a plurality of fields (ie, 1910 to 1950).

In this case, the WUR channel field 1910 may include information about a reception channel (or resource unit) of the wakeup packet WUP received on the WUR terminal.

The Measured WUR Packet PER field 1920 may include a Packet Error Rate (PER) value for the WUP packet received at the WUR terminal.

The Number of Received WUR Packet field 1930 may include information on the number of WUP packets successfully received by the WUR terminal after performing the combining procedure with the WUR terminal and the AP. .

The received SINR field 1940 of the WUR packet may include information on a Signal-to-Interference-plus-Noise Ratio (SINR) value of the wake-up packet WUP received at the WUR terminal.

The received time of the WUR packet field 1950 may include information on the reception time of the wake-up packet WUP received at the WUR terminal.

In the second case, when a value corresponding to '1' is set by the indicator of the measurement type field (ie, 1710 and 1810) of the WUR measurement notification packet (that is, as shown in FIG. 16, a plurality of WUR measurement packets (eg, FIG. 16). WUP # m1 to WUP # m4) are transmitted, the WUR terminal may configure the WUR measurement result packet 1900 based on a plurality of fields (ie, 1910 to 1940). That is, the reception time field 1950 of the WUR packet may be omitted.

In this case, the WUR channel field 1910 may include information about a channel on which a plurality of WUR measurement packets (eg, WUP # m1 to WUP # m4 of FIG. 16) are received (or a resource unit).

The measurement WUP packet PER field 1920 may include a packet error rate (PER) value for a plurality of WUR measurement packets (eg, WUP # m1 to WUP # m4 of FIG. 16).

For example, the WUR terminal may include an average PER value for a plurality of WUR measurement packets (eg, WUP # m1 to WUP # m4 of FIG. 16) in the measured WUP packet PER field 1920.

The received WUR packet number field 1930 may include information on the number of successfully received packets among a plurality of WUR measurement packets (eg, WUP # m1 to WUP # m4 of FIG. 16).

The received SINR field 1940 of the WUR packet includes information on signal-to-interference-plus-noise ratio (SINR) values for a plurality of WUR measurement packets (for example, WUP # m1 to WUP # m4 of FIG. 16). Can be.

The description of the case in which the indicator corresponding to the measurement type field (ie, 1710 and 1810) of the WUR measurement notification packet is set to '1' indicates that a plurality of measurement packets are transmitted at one transmission rate determined by the AP. It is assumed on the case.

If a plurality of measurement packets are transmitted at various types of transmission rates, it will be understood that a WUR measurement result packet having a structure in which a plurality of fields (ie, 1910 to 1940) are repeated corresponding to each measurement packet may be transmitted. will be.

20 is a diagram illustrating a WUR measurement result packet according to another exemplary embodiment.

1 to 20, the AP sequentially processes a plurality of WUR measurement packets (eg, WUP # m1 to WUP # m4 of FIG. 16) through a plurality of subchannels (eg, 1211, 1212, and 1213). I can send it.

According to another embodiment of the present invention, the WUR terminal performs a measurement operation on a plurality of WUR measurement packets (eg, WUP # m1 to WUP # m4 of FIG. 16) sequentially received for each subchannel (eg, 1211, 1212, and 1213). It can be done individually.

The WUR terminal according to another embodiment may include the measurement results for each subchannel (eg, 1211, 1212, 1213) in a plurality of fields (ie, 2010 to 2050).

For example, when a plurality of WUR measurement packets (eg, WUP # m1 to WUP # m4 of FIG. 16) are sequentially received through three subchannels (eg, 1211, 1212, and 1213), the present disclosure may be applied to another embodiment. The WUR terminal may transmit a WUR measurement result packet generated by repeating a plurality of fields (ie, 2010 to 2050) three times to the AP.

21 is a block diagram illustrating a wireless terminal to which an embodiment of the present specification can be applied. Referring to FIG. 21, a wireless terminal may be an STA capable of implementing the above-described embodiment and may be an AP or a non-AP STA. The wireless terminal may correspond to the above-described user or may correspond to a transmitting terminal for transmitting a signal to the user.

The AP 2100 includes a processor 2110, a memory 2120, and an RF unit 2130.

The RF unit 2130 may be connected to the processor 2110 to transmit / receive a radio signal.

The processor 2110 may implement the functions, processes, and / or methods proposed herein. For example, the processor 2110 may perform an operation according to the present embodiment described above. The processor 2110 may perform an operation of the AP disclosed in the present embodiment of FIGS. 1 to 20.

The non-AP STA 2150 includes a processor 2160, a memory 2170, and an RF unit 2180.

The RF unit 2180 may be connected to the processor 2160 to transmit / receive a radio signal.

The processor 2160 may implement the functions, processes, and / or methods proposed in the present embodiment. For example, the processor 2160 may be implemented to perform the non-AP STA operation according to the present embodiment described above. The processor 2160 may perform an operation of the non-AP STA disclosed in the present embodiment of FIGS. 1 to 20.

Processors 2110 and 2160 may include application-specific integrated circuits (ASICs), other chipsets, logic circuits, data processing devices, and / or converters that convert baseband signals and wireless signals to and from each other. The memories 2120 and 2170 may include read-only memory (ROM), random access memory (RAM), flash memory, memory cards, storage media, and / or other storage devices. The RF unit 2130 and 2180 may include one or more antennas for transmitting and / or receiving a radio signal.

When the embodiment of the present specification is implemented in software, the above-described technique may be implemented as a module (process, function, etc.) for performing the above-described function. The module may be stored in the memories 2120 and 2170 and executed by the processors 2110 and 2160. The memories 2120 and 2170 may be inside or outside the processors 2110 and 2160, and may be connected to the processors 2110 and 2160 by various well-known means.

In the detailed description of the present specification, specific embodiments have been described, but various modifications are possible without departing from the scope of the present specification. Therefore, the scope of the present specification should not be limited to the above-described embodiments, but should be determined not only by the claims below but also by the equivalents of the claims of the present invention.

Claims (10)

1. In a method for transmitting a packet for a WUR terminal including a main radio module and a WUR (Wake-Up Receiver) module in a WLAN system,

   An AP transmits a WUR Measurement Notification packet to the WUR terminal to determine a transmission rate of a wake-up packet instructing the main radio module to enter an activated state. Making;

   When a first acknowledgment packet is received from the WUR terminal in response to the WUR measurement notification packet, a plurality of WUR Measurement Packets are sequentially transmitted by the AP, but the plurality of WUR measurements are received. Each packet including a payload modulated according to an on-off keying (OOK) technique for the WUR module;

   Receiving, by the AP, a WUR measurement result packet including measurement information for the plurality of WUR measurement packets from the WUR terminal,

   The WUR measurement notification packet includes information on the number of the plurality of WUR measurement packets and information on the measurement interval allocated for the plurality of WUR measurement packets.
2. According to claim 1,

   The measurement information is measured by the WUR terminal based on the plurality of WUR measurement packets.
3. According to claim 1,

   The measurement information includes information on the number of packets received by the WUR terminal during the measurement interval among the plurality of WUR measurement packets, a packet error rate (PER) value for the plurality of WUR measurement packets, and the plurality of WUR measurement packets. Including the SINR value for.
4. According to claim 1,

   And the WUR module remains turned on during the measurement interval to receive the plurality of WUR measurement packets after transmission of the first grant packet.
5. According to claim 1,

   The WUR measurement notification packet is modulated by the AP according to an orthogonal frequency division multiplexing (OFDM) scheme.

   The WUR measurement result packet is modulated by the WUR terminal according to an OFDM scheme based on a main radio module.
6. According to claim 1,

   The WUR measurement notification packet further includes an indicator for notifying transmission of the plurality of WUR measurement packets, information on a transmission start time of the plurality of WUR measurement packets, and information on a transmission completion time of the plurality of WUR measurement packets.
7. According to claim 1,

   The payload is based on an ON signal determined as a 1 bit ON signal by the WUR module and an OFF signal determined as a 1 bit OFF signal by the WUR module. How it is implemented.
8. According to claim 1,

   The on signal is obtained by performing an Inverse Fast Fourier Transform (IFFT) on N2 subcarriers among N1 subcarriers corresponding to channel bands for the plurality of WUR measurement packets, and preset to the N2 subcarriers. Sequence is applied, and wherein N1 and N2 are natural numbers.
9. A second wireless terminal for performing a method for transmitting a packet for a first wireless terminal including a main radio module and a wake-up receiver (WUR) module in a wireless LAN system, wherein the second wireless terminal includes:

   A transceiver for transmitting and receiving a radio signal; And

   A processor coupled to the transceiver, wherein the processor includes:

   And transmit a WUR Measurement Notification packet to the first wireless terminal to determine a transmission rate of a wake-up packet instructing the main radio module to enter an activated state.

   When a first acknowledgment packet is received from the first wireless terminal in response to the WUR measurement notification packet, a plurality of WUR measurement packets are sequentially transmitted, wherein the plurality of WUR measurement packets are implemented. Each includes a payload modulated according to On-Off Keying (OOK) technique for the WUR module,

   Is configured to receive a WUR measurement result packet including measurement information for the plurality of WUR measurement packets from the first wireless terminal,

   The WUR measurement notification packet includes information on the number of the plurality of WUR measurement packets and information on the measurement interval allocated for the plurality of WUR measurement packets.
10. The method of claim 9,

    And the measurement information is measured by the first wireless terminal based on the plurality of WUR measurement packets.

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