WO2018056686A1 - Method for managing power of wireless terminal in wireless lan system and wireless terminal using same - Google Patents

Abstract

A method for managing power of a wireless terminal in a wireless LAN system according to an embodiment comprises the steps of: a first wireless terminal, which comprises a main radio module and a WUR module, transmitting to a second wireless terminal a turn-off packet for indicating that the main radio module enters into a deactivated state; controlling the main radio module to enter into a deactivated state; receiving from the second wireless terminal a wake-up packet for enabling the main radio module to enter into an activated state; and controlling the main radio module to enter into an activated state, wherein the wake-up packet comprises a payload modulated by means of an OOK technique for the WUR module.

Description

Method for managing power of wireless terminal in wireless LAN system and wireless terminal using same

The present disclosure relates to wireless communication, and more particularly, to a method for managing power of a wireless terminal in a wireless LAN 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. 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 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 effectively managing the power of a wireless terminal in a wireless LAN system for low power communication and a wireless terminal using the same.

In a method for managing power of a wireless terminal in a wireless LAN system according to an embodiment of the present disclosure, a first wireless terminal including a main radio module and a WUR module enters into a deactivated state. Transmitting an indication turn-off packet to a second wireless terminal; Controlling the main radio module to enter an inactive state; Receiving a wakeup packet from the second wireless terminal to enter the main radio module into an activated state, the wakeup packet including a payload modulated according to the OOK technique for the WUR module; And controlling the main radio module to enter an activated state.

According to one embodiment of the present specification, a method for effectively managing power of a wireless terminal in a wireless LAN system for low power communication and a wireless terminal using the same are provided.

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.

10 is a diagram illustrating a transmission procedure of a turn-off packet according to the present embodiment.

11 is a diagram illustrating a turn-off packet according to the present embodiment.

12 is a flowchart illustrating a method for managing power of a wireless terminal in a wireless LAN system based on a turn-off packet according to the present embodiment.

FIG. 13 is a diagram for describing a method for managing power of a wireless terminal in a wireless LAN system based on a retransmission procedure according to another embodiment.

14 is a diagram for describing a method for managing power of a wireless terminal in a wireless LAN system based on a turn-off packet according to another exemplary embodiment.

15 is a flowchart illustrating a method for managing power of a wireless terminal in a wireless LAN system based on a turn-off packet according to another embodiment of the present invention.

16 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 may be in an inactive state (ie, an OFF state), and the WUR module 412 may be in a turn-on state (ie, an ON state).

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 instructs 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. can do.

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

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

For example, the 802.11 STA may detect the beginning of a packet through the L-STF field in the legacy preamble 610. The STA may detect an end portion of the 802.11 packet through the L-SIG field in the legacy preamble 610.

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.

The legacy preamble 610 may be understood as a field for a third party legacy STA (STA that does not include the LP-WUR). In other words, the legacy preamble 610 may not be decoded by the LP-WUR.

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-signal and an OFF-signal.

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

Referring to the frequency domain graph 920, the ON signal included in the payload (eg, 620 of FIG. 6) is N2 among N1 subcarriers (N1 is a natural number) corresponding to the channel band of the wakeup packet (WUP). Can be obtained by performing IFFT on the 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 for the OFF-signal included in the payload (eg, 620 of FIG. 6) of the wakeup packet WUP. The off signal may be a signal that does not have an actual power value. That is, the off signal may not be considered in the configuration of the wakeup packet (WUP).

The ON signal included in the payload (620 of FIG. 6) of the wakeup packet WUP is determined as a 1-bit ON signal (ie, '1') by the WUR module (eg, 512 of FIG. 5) That is, demodulation). Similarly, the off 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 wireless terminal (eg, 510 of FIG. 5) including a WUR module (eg, 512 of FIG. 5) demodulates a received packet based on an envelope detector that extracts an envelope of the received signal. (demodulate)

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).

Hereinafter, a procedure for the main radio module in the activated state to enter the deactivated state again according to the wakeup packet WUP will be described.

10 is a diagram illustrating a transmission procedure of a turn-off packet according to the present embodiment. 1 to 10, the WLAN system 1000 according to the present embodiment may include a first wireless terminal 1010 and a second wireless terminal 1020.

5 and 10, the first wireless terminal 1010 of FIG. 10 may be understood as a non-AP STA corresponding to the first wireless terminal 510 of FIG. 5. In addition, the second wireless terminal 102 of FIG. 10 may be understood as an AP STA corresponding to the second wireless terminal 520 of FIG. 5.

The first wireless terminal 1010 of FIG. 10 may include a WUR module 1012 that includes a main radio module 1011 associated with a main radio (ie, 802.11) and a low power wake up receiver (LP WUR).

For example, the main radio module 1011 may include a plurality of circuits for supporting Wi-Fi, Bluetooth® radio (hereinafter referred to as BT radio) and Bluetooth® Low Energy radio (hereinafter referred to as BLE radio).

In addition, the WUR module 1012 may include a plurality of circuits for supporting Bluetooth® radio (hereinafter referred to as BT radio) and Bluetooth® Low Energy radio (hereinafter referred to as BLE radio).

The main radio module 1011 may be in an activated state (ie, an ON state) or in an inactive state (ie, an OFF state).

For example, the first wireless terminal 1010 may transmit a packet (eg, 1021 of FIG. 10) to the second wireless terminal 1020 using the main radio module 1011 in an activated state (ie, an ON state). have.

In addition, the first wireless terminal 1010 may receive packets (eg, 521 and 522 of FIG. 5) from the second wireless terminal 1020 using the main radio module 1011 in an activated state (ie, in an ON state). Can be.

If there is no packet (or data) to be transmitted by the first wireless terminal 1010, the main radio module 1011 may enter an inactive state (ie, an OFF state).

For example, until the main radio module 1011 is woken up by the WUR module 1012, the first radio terminal 1010 uses the main radio module 1011 in a deactivated state (ie, in an OFF state). It is not possible to receive a beacon frame periodically transmitted by the wireless terminal 1020.

The WUR module 1012 according to the present embodiment may be understood as an apparatus for switching the main radio module 1011 from an inactive state (ie, an OFF state) to an active state (ie, an ON state).

The WUR module 1012 may not include a transmitter for transmitting a packet to the second wireless terminal 1020. The WUR module 1012 may include a receiver for transmitting packets to the second wireless terminal 1020. In this case, the receiver of the WUR module 1012 may be implemented based on the envelope detector mentioned above with reference to FIG. 5.

For brevity of FIG. 10, the main radio module 1011 of FIG. 10 is in an activated state (ie, in an ON state) according to a wakeup packet (WUP, not shown) previously received from the second wireless terminal 1020. Assume

For example, if there is no frame to be transmitted by the first wireless terminal 1010, the first wireless terminal 1010 may use the main radio module 1011 for power saving of the first wireless terminal 1010. It can be controlled to enter this inactive state (ie, OFF state).

In order to inform the second wireless terminal 1020 in advance that the main radio module 1011 enters an inactive state (ie, an OFF state), the first wireless terminal 1010 informs the main radio module 1011. The turn-off packet 1021 may be transmitted.

The first wireless terminal 1010 may control the main radio module 1011 to enter an inactive state (ie, an OFF state) immediately after transmission of the turn-off packet 1021.

Alternatively, although not shown in FIG. 10, after an acknowledgment (ACK) frame is received from the second wireless terminal 1020 in response to the turn-off packet 1021, the first wireless terminal 1010 may receive a main radio module ( 1011 may be controlled to enter an inactive state (ie, an OFF state).

The turn-off packet 1021 of FIG. 10 according to the present embodiment may be transmitted in various ways.

In a first manner, the turn-off packet 1021 may be understood as a separately defined frame transmitted by the first wireless terminal 1010.

In a second manner, for transmission of turn-off packet 1021, an acknowledgment ('ACK') frame is provided to indicate successful reception of a data packet (not shown) received from second wireless terminal 1020. Can be used.

For example, a data packet (not shown) in which an EOSP (End of Service Period) field is set to '1' may be received by the main radio module 1011 of the first wireless terminal 1010. In this case, the data packet (not shown) in which the EOSP field is set to '1' may be the last packet transmitted in a corresponding service period.

Accordingly, the first wireless terminal 1010 may inform the second wireless terminal 1020 that the main radio module 1011 enters an inactive state together with an acknowledgment (ACK) frame for a data packet (not shown). . After transmission of the acknowledgment (ACK) frame, the first wireless terminal 1010 may control the main radio module 1011 to enter an inactive state.

That is, the first wireless terminal 1010 may transmit a turn-off packet 1021 separately defined with an acknowledgment (ACK) frame for the data packet (not shown).

Alternatively, the first wireless terminal 1010 may transmit an acknowledgment (ACK) frame to the second wireless terminal 1020 and then transmit a turn-off packet 1021 separately defined in SIFS.

Alternatively, the first wireless terminal 1010 may transmit a reply-off packet 1021 through competition with another wireless terminal (not shown) after transmitting an acknowledgment (ACK) frame.

The second wireless terminal 1020 may not receive an acknowledgment (ACK) frame for a data packet (not shown) in which the EOSP field is set to '1' from the first wireless terminal 1010.

In this case, the second wireless terminal 1020 may consider that the main radio module 1011 of the first wireless terminal 1010 maintains an activation state even in a next service period. Accordingly, the second wireless terminal 1020 may repeatedly attempt to transmit a packet for the first wireless terminal 1010.

Alternatively, the second wireless terminal 1020 may consider that the main radio module 1011 of the first wireless terminal 1010 is in an inactive state. Accordingly, the second wireless terminal 1020 may transmit a wake-up packet (WUP, not shown) for waking up the main radio module 1011 of the first wireless terminal 1010.

As another example, a data packet (not shown) in which the More Data field is set to '0' may be received by the main radio module 1011 of the first wireless terminal 1010. That is, the first wireless terminal 1010 that receives a data packet (not shown) in which the More Data field is set to '0' may determine that there are no more packets to be received from the second wireless terminal 1020.

In this case, the first wireless terminal 1010 may transmit a separately defined turn-off packet 1021 together with an acknowledgment (ACK) frame for the data packet (not shown).

That is, the first wireless terminal 1010 may inform the second wireless terminal 1020 that the main radio module 1011 enters an inactive state together with an acknowledgment (ACK) frame for a data packet (not shown). Subsequently, the first wireless terminal 1010 may control the main radio module 1011 to enter an inactive state after transmission of the acknowledgment (ACK) frame.

Alternatively, the first wireless terminal 1010 may transmit a turn-off packet 1021 defined separately in the SIFS after transmitting the acknowledgment (ACK) frame.

Alternatively, the first wireless terminal 1010 may transmit a reply-off packet 1021 through competition with another wireless terminal (not shown) after transmitting an acknowledgment (ACK) frame.

In a third manner, the turn-off packet 1021 may be understood as a packet including operating mode indication (OMI) information of the first wireless terminal 1010. The third scheme is described in more detail with reference to FIG. 11 described below.

11 is a diagram illustrating a turn-off packet according to the present embodiment.

General OMI information may be transmitted to inform other wireless terminals of the operation mode to be changed by the wireless terminal. In addition, the OMI information may be included in the HT control field of the MAC header of the general MAC frame.

According to this embodiment, one bit (B9) of the three-bit reserved field for the conventional OMI information may be allocated to indicate the state of the main radio module of the wireless terminal.

10 and 11, the state of the conventional OMI information B0 to B8 and the main radio module 1011 of the wireless terminal are shown in a MAC header of the turn-off packet 1021 according to the present embodiment. OMI information 1100 corresponding to an indicator of one bit B9 for indicating may be included.

For example, the OMI information 1100 may include a plurality of fields 1101 to 1106 as shown in FIG. 11. In addition, the OMI information 1100 may further include fields not shown in FIG. 11 or may include only some of the fields shown in FIG. 11.

The Rx NSS field 1101 of FIG. 11 is used by a wireless terminal (eg, a non-AP STA) that transmits OMI information 1100 to receive a signal (eg, PPDU) from another wireless terminal (eg, an AP). The number of spatial streams may be indicated. Three bits (B0-B2) may be allocated for the Rx NSS field 1101.

The number of spatial streams allocated for the downlink PPDU to be received from another wireless terminal (eg, AP) may be indicated through the Rx NSS field 1101. That is, another wireless terminal (eg, an AP) may configure a downlink PPDU for the wireless terminal that transmits the OMI information 1100 with reference to the Rx NSS field 1101.

The Channel Width field 1102 may indicate an operating channel bandwidth of an operating channel supported by a wireless terminal (eg, a non-AP STA) transmitting the OMI information 1100. Two bits (B3-B4) may be allocated for the Channel Width field 1102.

For example, if a value set in the Channel Width field 1102 corresponds to '0', the bandwidth of the operation channel may indicate 20 MHz. If the value set in the Channel Width field 1102 corresponds to '1', the bandwidth of the operation channel may indicate 40 MHz.

For example, if a value set in the Channel Width field 1102 corresponds to '2', the bandwidth of the operation channel may indicate 80 MHz. If the value set in the Channel Width field 1102 corresponds to '3', the bandwidth of the operation channel may indicate 160 MHz or 80 + 80 MHz.

The UL MU Disable field 1103 may include a Multiple Input Multiple Output (MIMO) for a multi user in an uplink by a wireless terminal (eg, a non-AP STA) that transmits the OMI information 1100. Hereinafter, it may be indicated whether to participate in 'UL MU MIMO') transmission.

For example, if the wireless terminal determines not to participate in UL MU MIMO transmission for some reason (i.e., suspends UL MU operation), a specific value (e.g., ' 1 ') may be indicated.

As another example, if the wireless terminal determines to participate in the UL MU MIMO transmission for a specific reason (ie, when the UL MU operation resumes), a specific value (eg, '0' in the UL MU Disable field 1430) is determined. ') May be indicated.

The Tx NSS field 1104 is a number of spatial streams for transmitting a signal (for example, PPDU) by a wireless terminal (for example, a non-AP STA) that transmits the OMI information 1100 to another wireless terminal. Can be indicated.

According to the present embodiment, a turn-off indicator of one bit B9 may be allocated for the Tx Power field 1105. The turn-off indicator of the Tx Power field 1105 may be used to inform other wireless terminals of the state of the main radio module 1011 of FIG. 10.

For example, the wireless terminal (eg, 1010 of FIG. 10) may transmit a wake-up packet (WUP) in which the turn-off indicator of the Tx Power field 1105 is set to '0'. Can be sent by

Through this, the wireless terminal (eg, 1010 of FIG. 10) may inform another wireless terminal (eg, 1020 of FIG. 10) that the main radio module (eg, 1011) of the wireless terminal will maintain the current activation state.

As another example, the wireless terminal (eg, 1010 of FIG. 10) transfers a wake-up packet (WUP) in which the turn-off indicator of the Tx Power field 1105 is set to '1' to another wireless terminal (eg, 1020 of FIG. 10). I can send it.

Accordingly, the wireless terminal (eg, 1010 of FIG. 10) may instruct another wireless terminal (eg, 1020 of FIG. 10) that the main radio module (eg, 1011) of the wireless terminal enters the deactivation state from the activated state. have.

In the present specification, a packet including the OMI information 1100 of FIG. 11 may be understood as the wakeup packet WUP 1021 of FIG. 10.

11 is an example in which the Rx NSS 1101 and Tx NSS 1104 fields are separately configured, but it will be understood that the field may be modified.

For example, Rx NSS (i.e., number of spatial streams used for PPDU reception at a specific STA) and Tx NSS (i.e., number of spatial streams used for PPDU transmission at a specific STA) are provided through one NSS field. It may be possible to indicate in common.

In addition, the present disclosure is not limited to the contents shown in FIG. 11, and all bits B0-B11 allocated to the OMI information 1100 are notified to indicate that the main radio module in the wireless terminal enters an inactive state. Can be set to 0 'or' 1 '.

In addition, the operation mode announcement of the 8.6.23.4 section of IEEE 802.11 REVmc ™ / D4.1 for other legacy terminals (eg, terminals complying with IEEE 802.11 ac) as well as the scheme using the HT control field of the MAC frame shown in FIG. 11. It will be appreciated that it is also possible to indicate the status of the main radio module using an operation mode notification frame.

12 is a flowchart illustrating a method for managing power of a wireless terminal in a wireless LAN system based on a turn-off packet according to the present embodiment.

1 to 12, in step S1210, the first wireless terminal (eg, 1010 of FIG. 10) enters into a deactivation state of the main radio module (eg, 1011 of FIG. 10). An indication turn-off packet (eg, 1021 of FIG. 10) may be transmitted to a second wireless terminal (eg, 1020 of FIG. 10).

For example, a first wireless terminal (eg, 1010 of FIG. 10) may transmit a turn-off packet using a main radio module (eg, 1011 of FIG. 10).

Specifically, the turn-off packet includes a total of four subcarriers for protecting the left band, three subcarriers for protecting the right band, and a DC subcarrier corresponding to the DC frequency among 64 subcarriers for the 20 MHz band. It can be transmitted based on 56 subcarriers.

In other words, the second wireless terminal (eg, 1020 of FIG. 10) determines whether the main radio module (eg, 1011 of FIG. 10) enters a deactivation state according to the received turn-off packet (eg, 1021). Can be determined.

12, the second wireless terminal (eg, 1020 of FIG. 10) may determine that the main radio module (eg, 1011 of FIG. 10) enters an inactive state according to the turn-off packet (eg, 1021). have.

As another example, a maintenance packet (not shown) indicating that the main radio module (eg, 1011 of FIG. 10) does not enter an inactive state and remains active is a second wireless terminal (eg, 1020 of FIG. 10). ) May be received.

In this case, the second wireless terminal (eg, 1020 of FIG. 10) may determine that the main radio module (eg, 1011 of FIG. 10) does not enter an inactive state and maintains an active state according to a maintenance packet (not shown). Can be.

In operation S1220, the first wireless terminal (eg, 1010 of FIG. 10) may control the main radio module (eg, 1011 of FIG. 10) to enter an inactive state.

For example, the first wireless terminal (eg, 1010 of FIG. 10) may control the main radio module (eg, 1011 of FIG. 10) to enter an inactive state based on primitive information inside the terminal.

In operation S1230, the first wireless terminal (eg, 1010 of FIG. 10) may determine whether the aforementioned wakeup packet (WUP, eg, 521 of FIG. 5) is received.

For example, if the second wireless terminal (eg, 1020 of FIG. 10) buffers a data packet for the first wireless terminal (eg, 1010 of FIG. 10), a wakeup packet (WUP, eg, 521 of FIG. 5). May be received from a second wireless terminal (eg, 1020 of FIG. 10).

The wakeup packet (WUP) according to the present embodiment is a page modulated according to the on-off keying (OOK) technique for legacy information (610 in FIG. 6) and a WUR module (for example, 1012 in FIG. 10) for the legacy terminal. Payload (620 of FIG. 6).

In this case, the payload 620 of FIG. 6 may be implemented based on an ON signal and an OFF signal.

For example, the ON signal includes a first subcarrier set (eg, 921 of FIG. 9) corresponding to 13 consecutive subcarriers among 64 subcarriers for a 20 MHz band as shown in FIG. 9, and an ON signal. It may be obtained by performing a 64-point Inverse Fast Fourier Transform (IFFT) on the basis of a preset first sequence for a signal.

In addition, a coefficient for a DC subcarrier of a DC frequency in the first subcarrier set may be set to '0'. A plurality of coefficients for the remaining subcarriers except the DC subcarrier in the first subcarrier set (eg, 921 of FIG. 9) may be set to '1' or '-1'.

For example, the OFF signal may include a second subcarrier set (not shown) corresponding to 13 consecutive subcarriers among 64 subcarriers for the 20 MHz band as shown in FIG. 9, and a second preset second signal for the off signal. It can be obtained by performing a 64-point Inverse Fast Fourier Transform (IFFT) based on the sequence. In this case, all of the plurality of coefficients for the second subcarrier set may be set to '0'.

Alternatively, the OFF signal may not be transmitted by the second wireless terminal (eg, 1020).

The ON signal included in the payload 620 of FIG. 6 may be determined as a 1-bit ON signal corresponding to '1' by the WUR module (eg, 1012 of FIG. 10). .

The OFF signal included in the payload 620 of FIG. 6 may be determined as a 1-bit OFF signal corresponding to '0' by the WUR module (eg, 1012 of FIG. 10). .

If the wakeup packet WUP (eg, 521 of FIG. 5) is not received from the second wireless terminal (eg, 1020 of FIG. 10), the procedure ends.

If a wakeup packet WUP (eg, 521 of FIG. 5) is received from the second wireless terminal (eg, 1020 of FIG. 10), the procedure goes to step S1240.

In operation S1240, the first wireless terminal (eg, 1010 of FIG. 10) may control the main radio module (eg, 1011 of FIG. 10) to enter an activation state.

For example, a first wireless terminal (eg, 1010 of FIG. 10) enters an active state of a main radio module (eg, 1011 of FIG. 10) according to a received wake-up packet (WUP, eg, 521 of FIG. 5). A wake up signal (eg, 523 of FIG. 5) may be transmitted.

In this case, the wakeup signal (eg, 523 of FIG. 5) may be implemented based on internal primitive information of the first wireless terminal (eg, 1010 of FIG. 10).

In operation S1250, the first wireless terminal (eg, 1010 of FIG. 10) uses the main radio module (eg, 1011 of FIG. 10) that is in an activated state to transmit a data packet from the second wireless terminal (eg, 1020 of FIG. 10). Can be received. It may be assumed that the data packet for the first wireless terminal (eg, 1010 of FIG. 10) is received based on a channel band of 20 MHz.

That is, the data packet for the first wireless terminal (eg, 1010 of FIG. 10) includes four subcarriers for protecting the left band, three subcarriers for protecting the right band, and 64 subcarriers for the 20 MHz band. It may be received based on 56 subcarriers except the DC subcarrier of the DC frequency.

According to the present embodiment, the state of the main radio module of the wireless terminal and the state of the WUR module may be related to each other or may be independent of each other.

For example, it may be assumed that the main radio module is inactive and the WUR module is in active state. Thereafter, even if the main radio module enters the activated state, the WUR module may remain activated.

For example, it may be assumed that the main radio module is inactive and the WUR module is in active state. Thereafter, when the main radio module enters the active state, the WUR module may enter the inactive state. Subsequently, the WUR module may remain inactive until the main radio module enters the inactive state again.

FIG. 13 is a diagram for describing a method for managing power of a wireless terminal in a wireless LAN system based on a retransmission procedure according to another embodiment.

FIG. 13 illustrates that a wakeup packet WUP is not transmitted by a first wireless terminal (eg, 1010 of FIG. 10) even when a main radio module (eg, 1011 of FIG. 10) of the first wireless terminal enters an inactive state. Show the case.

1 to 13, in step S1310, the second wireless terminal (eg, 1020 of FIG. 10) is the main radio module (eg, 1011 of FIG. 10) of the first wireless terminal (eg, 1010 of FIG. 10). May transmit a data packet for the first wireless terminal.

In operation S1320, the second wireless terminal (eg, 1020 of FIG. 10) may determine whether an acknowledgment (ACK) frame for the transmitted data packet is received from the first wireless terminal (eg, 1010 of FIG. 10). .

If an acknowledgment (ACK) frame for the transmitted data packet is received from the first wireless terminal (eg, 1010 of FIG. 10), the procedure may end.

If an acknowledgment (ACK) frame for the transmitted data packet is not received from the first wireless terminal (eg, 1010 of FIG. 10), the procedure goes to step S1330.

In step S1330, the second wireless terminal (eg, 1020 of FIG. 10) may retransmit the same data packet as the data packet already transmitted in step S1310.

In operation S1340, the second wireless terminal (eg, 1020 of FIG. 10) may determine whether an acknowledgment (ACK) frame for the retransmitted data packet is received from the first wireless terminal (eg, 1010 of FIG. 10). .

If an acknowledgment (ACK) frame for the retransmitted data packet is received from the first wireless terminal (eg, 1010 of FIG. 10), the procedure may end.

If an acknowledgment (ACK) frame for the retransmitted data packet is not received from the first wireless terminal (eg, 1010 of FIG. 10), the procedure proceeds to step S1350.

In operation S1350, the second wireless terminal (eg, 1020 of FIG. 10) may determine whether the total number of retransmission operations for the data packet exceeds a predetermined threshold number. For example, the predetermined threshold number may be '3'.

If the total number of times that the retransmission operation is performed on the data packet does not exceed a predetermined threshold number (eg, three times), step S1330 may be performed again.

If the total number of times that the retransmission operation is performed on the data packet exceeds a predetermined threshold number (for example, three times), the second radio terminal (for example, 1020 of FIG. 10) may be connected to the main radio module (eg, the first radio terminal) of the first radio terminal. For example, it may be determined that 1011 of FIG. 10 is in an inactive state. Accordingly, the procedure proceeds to step S1360.

In operation S1360, the second wireless terminal (eg, 1020 of FIG. 10) may include a wake-up packet (WUP) that instructs the main radio module (eg, 1011 of FIG. 10) of the first wireless terminal to enter the activated state again. 5, 521 may be transmitted to a WUR module (eg, 1012 of FIG. 10) of the first wireless terminal.

In this case, the wakeup packet WUP (eg, 521 of FIG. 5) may include a payload (620 of FIG. 6) modulated according to the on-off keying (OOK) technique mentioned in FIG. 12.

14 is a diagram for describing a method for managing power of a wireless terminal in a wireless LAN system based on a turn-off packet according to another exemplary embodiment.

1 through 9 and 14, the first wireless terminal 1410 of FIG. 14 corresponds to the first wireless terminal 1010 of FIG. 10, and the second wireless terminal 1420 of FIG. 14 is illustrated in FIG. 10. May correspond to the second wireless terminal 1020.

14, the WUR module 1412 of the first wireless terminal 1410 may transmit a packet to the second wireless terminal 1020 as well as a receiver for receiving the packet from the second wireless terminal 1420. It may further include a transmitter.

For the sake of brevity of FIG. 14, it is assumed that the main radio module 1411 is in an activated state (ie, an ON state) according to a wakeup packet WUP (not shown) previously received from the second wireless terminal 1420.

For example, if there is no frame to be transmitted by the first wireless terminal 1410, the first wireless terminal 1410 may be connected to the main radio module 1411 for power saving of the first wireless terminal 1410. It can be controlled to enter this inactive state (ie, OFF state).

In order to inform the second wireless terminal 1420 in advance that the main radio module 1411 of the first wireless terminal 1410 enters an inactive state (that is, an OFF state), the first wireless terminal 1410 is configured as a WUR module. 1411 may be used to transmit turn-off packet 1421.

For example, the turn-off packet 1421 transmitted through the WUR module 1411 may be modulated according to the on-off keying (OOK) technique described above. The procedure in which the turn-off packet 1421 is transmitted based on the WUR module 1411 is described in more detail with reference to FIG. 15 to be described later.

15 is a flowchart illustrating a method for managing power of a wireless terminal in a wireless LAN system based on a turn-off packet according to another embodiment of the present invention.

1 through 9, 14, and 15, the first wireless terminal 1510 of FIG. 15 may be understood to correspond to the first wireless terminal 1410 of FIG. 14. In addition, it may be understood that the main radio module 1511 and the WUR module 1512 of FIG. 15 correspond to the main radio module 1411 and the WUR module 1412 of FIG. 14, respectively.

The second wireless terminal 1520 may be understood to correspond to the second wireless terminal 1420 of FIG. 14.

The vertical axis of the main radio module 1511 included in the first wireless terminal 1510 may represent a time t1 for the main radio module 1511. The vertical axis of the WUR module 1512 included in the first wireless terminal 1510 may represent a time t2 for the WUR module 1512.

The vertical axis t3 of the second wireless terminal 1520 may represent a time t3 for the second wireless terminal 1520.

In operation S1510, the main radio module 1511 may transmit the turn-off request signal 1423 of FIG. 14 to the WUR module 1512. For example, the turn-off request signal 1423 of FIG. 14 may be implemented based on primitive information inside the wireless terminal 1510.

For example, the turn-off request signal 1423 in FIG. 14 may be used to transition the main radio module 1511 in an active state (ie, an ON state) to an inactive state (ie, an OFF state).

In operation S1520, the first wireless terminal 1510 may transmit a turn-off packet 1421 to the second wireless terminal 1520 using the WUR module 1512. For example, the WUR module 1512 may configure the turn-off packet 1421 according to the turn-off request signal (eg, 1423 of FIG. 14).

For example, the turn-off packet (eg, 1421 of FIG. 14) may be modulated according to the OOK technique, unlike the turn-off packet of FIG. 10 (eg, 1021 of FIG. 14).

In operation S1530, the second wireless terminal 1520 may transmit an acknowledgment (ACK) frame for notifying successful reception of the turn-off packet 1421 to the first wireless terminal 1510.

For example, the second wireless terminal 1520 may modulate an acknowledgment (ACK) frame to be received based on the main radio module 1511. Alternatively, the second wireless terminal 1520 may modulate an acknowledgment (ACK) frame to be received based on the WUR module 1512.

In operation S1540, the WUR module 1512 may transmit a turn-off response signal to the main radio module 1511 according to an acknowledgment (ACK) frame. The turn-off response signal may be implemented based on primitive information inside the wireless terminal 1510.

In operation S1550, the main radio module 1511 may be switched from the activated state to the deactivated state according to the turn-off response signal.

Unlike the one shown in FIG. 15, once the main radio module 1511 passes the turn-off request signal (1423 of FIG. 14) to the WUR module 1512, the main radio module 1511 receives the second radio terminal 1520. It may be switched to an inactive state without waiting for an acknowledgment (ACK) frame for the turn-off packet (1421).

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

Referring to FIG. 16, a wireless terminal may be an STA or an AP or a non-AP STA that may implement the above-described embodiment. 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 1600 includes a processor 1610, a memory 1620, and an RF unit 1630.

The RF unit 1630 may be connected to the processor 1610 to transmit / receive a radio signal.

The processor 1610 may implement the functions, processes, and / or methods proposed herein. For example, the processor 1610 may perform an operation according to the present embodiment described above. The processor 1610 may perform an operation of the AP disclosed in the present embodiment of FIGS. 1 to 15.

The non-AP STA 1650 includes a processor 1660, a memory 1670, and an RF unit 1680.

The RF unit 1680 may be connected to the processor 1660 to transmit / receive a radio signal.

The processor 1660 may implement the functions, processes, and / or methods proposed in the present embodiment. For example, the processor 1660 may be implemented to perform the non-AP STA operation according to the present embodiment described above. The processor 1660 may perform an operation of the non-AP STA disclosed in the present embodiment of FIGS. 1 to 15.

Processors 1610 and 1660 may include application-specific integrated circuits (ASICs), other chipsets, logic circuits, data processing devices, and / or converters to convert baseband signals and wireless signals to and from each other. The memories 1620 and 1670 may include read-only memory (ROM), random access memory (RAM), flash memory, memory cards, storage media and / or other storage devices. The RF unit 1630 and 1680 may include one or more antennas for transmitting and / or receiving a wireless 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. Modules may be stored in memories 1620 and 1670 and executed by processors 1610 and 1660. The memories 1620 and 1670 may be inside or outside the processors 1610 and 1660, and may be connected to the processors 1610 and 1660 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 the method for managing the power of the wireless terminal in a wireless LAN system,

   A first wireless terminal including a main radio module and a wake-up receiver module transmits a turn-off packet indicating that the main radio module enters a deactivation state. Transmitting to a wireless terminal;

   Controlling, by the first wireless terminal, the main radio module to enter the deactivated state;

   The first wireless terminal receives a wake-up packet for entering the main radio module into the activated state from the second wireless terminal, wherein the wake-up packet is OOK (for a WUR module) A payload modulated according to an On-Off Keying) technique; And

   And controlling, by the first wireless terminal, the main radio module to enter the activated state.
2. 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.
3. The method of claim 2,

   The on signal is obtained by performing an Inverse Fast Fourier Transform (IFFT) on N2 subcarriers among N1 subcarriers corresponding to the channel band of the wakeup packet, and a predetermined sequence is applied to the N2 subcarriers. How to be.
4. The method of claim 3, wherein

   The channel band is 20MHz, the N1 subcarriers are 64 subcarriers, the N2 subcarriers are 13 consecutive subcarriers, the preset sequence is a 13-bit sequence, and is applied to the wakeup packet. The subcarrier spacing is 312.5 kHz.
5. The method of claim 4, wherein

   And a coefficient corresponding to the DC subcarrier in the 13-bit sequence is '0' and the remaining coefficients are set to '1' or '-1'.
6. The method of claim 2,

   The on signal and the off signal are transmitted based on a 4.06 MHz band.
7. According to claim 1,

   The turn-off packet includes operating mode indication information indicating an operation mode of the first wireless terminal,

   The operation mode indication information includes a turn-off indicator indicating whether the main radio module maintains the activation state or enters the deactivation state from the activation state.
8. According to claim 1,

   The main radio module includes a first receiver for receiving the data packet and a first transmitter for transmitting the turn-off packet,

   The WUR module includes a second receiver implemented based on an envelope detector for detecting an envelope of the wakeup packet.
9. According to claim 1,

   The beacon frame periodically transmitted by the second wireless terminal is not received by the first wireless terminal entering the deactivated state.
10. A first wireless terminal including a main radio module and a wake-up receiver module for a method for managing power of a wireless terminal in a wireless LAN system, wherein the first 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 turn-off packet to a second wireless terminal indicating that the main radio module enters a deactivation state,

    Control the main radio module to enter the deactivated state;

    And configured to receive a wake-up packet for entering the main radio module into the activated state from the second wireless terminal, the wake-up packet being OOK (On-Off Keying) for the WUR module. Includes a payload modulated according to the technique,

    And a main terminal configured to control the main radio module to enter the activated state.

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