WO2017164687A1 - Procédé de gestion de puissance dans un système lan sans fil et terminal sans fil l'utilisant - Google Patents

Procédé de gestion de puissance dans un système lan sans fil et terminal sans fil l'utilisant Download PDF

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Publication number
WO2017164687A1
WO2017164687A1 PCT/KR2017/003186 KR2017003186W WO2017164687A1 WO 2017164687 A1 WO2017164687 A1 WO 2017164687A1 KR 2017003186 W KR2017003186 W KR 2017003186W WO 2017164687 A1 WO2017164687 A1 WO 2017164687A1
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Prior art keywords
twt
sta
field
frame
information
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PCT/KR2017/003186
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English (en)
Korean (ko)
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류기선
김정기
김서욱
박현희
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엘지전자 주식회사
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
    • H04W52/02—Power saving arrangements
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W76/00—Connection management
    • H04W76/20—Manipulation of established connections
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W84/00—Network topologies
    • H04W84/02—Hierarchically pre-organised networks, e.g. paging networks, cellular networks, WLAN [Wireless Local Area Network] or WLL [Wireless Local Loop]
    • H04W84/10—Small scale networks; Flat hierarchical networks
    • H04W84/12—WLAN [Wireless Local Area Networks]
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
    • Y02D30/00—Reducing energy consumption in communication networks
    • Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks

Definitions

  • the present disclosure relates to wireless communication, and more particularly, to a method for power management in a WLAN system and a wireless terminal using the same.
  • next-generation WLANs 1) enhancements to the Institute of Electronics and Electronics Engineers (IEEE) 802.11 physical physical access (PHY) and medium access control (MAC) layers in the 2.4 GHz and 5 GHz bands, and 2) spectral efficiency and area throughput. aims to improve performance in real indoor and outdoor environments, such as in environments where interference sources exist, dense heterogeneous network environments, and high user loads.
  • IEEE Institute of Electronics and Electronics Engineers
  • PHY physical physical access
  • MAC medium access control
  • next-generation WLAN The environment mainly considered in the next-generation WLAN is a dense environment having many access points (APs) and a station (STA), and improvements in spectral efficiency and area throughput are discussed in such a dense environment.
  • next generation WLAN there is an interest in improving practical performance not only in an indoor environment but also in an outdoor environment, which is not much considered in a conventional WLAN.
  • scenarios such as a wireless office, a smarthome, a stadium, and a hotspot are of interest in the next generation WLAN.
  • a discussion of performance improvement of a WLAN system in an environment in which APs and STAs are concentrated is in progress.
  • An object of the present specification is to provide a method for power management for reducing power consumed in a WLAN system and a wireless terminal using the same.
  • a method for power management includes accessing a beacon frame including TWT parameter information for a broadcast target awake time service period in which a user STA is preset.
  • the user STA receiving from a point, the user STA to switch from the doze state to the awake state in the broadcast TWT service interval based on the TWT parameter information, the user STA in the broadcast TWT service interval Receive a TWT service frame including subsequent TWT parameter information for a subsequent TWT service interval that is individually configured for the subsequent TWT parameter information is information included in the Medium Access Control header of the TWT service frame Step, the user STA from the awake state after the broadcast TWT service interval Switching step of switching to the user's status, and this STA from the doze state in a subsequent service interval based on a subsequent TWT TWT parameter information to the awake state, and performing a communication with the AP.
  • a method for power management for reducing power consumed in a WLAN system and a wireless terminal using the same are provided.
  • FIG. 1 is a conceptual diagram illustrating a structure of a WLAN system.
  • FIG. 2 is a diagram illustrating an example of a PPDU used in the IEEE standard.
  • FIG. 3 is a diagram illustrating an example of a HE PPDU.
  • 4 is a diagram illustrating an arrangement of resource units used on a 20 MHz band.
  • 5 is a diagram illustrating an arrangement of resource units used on a 40 MHz band.
  • 6 is a diagram illustrating an arrangement of resource units used on an 80 MHz band.
  • FIG. 7 is a diagram illustrating another example of the HE-PPDU.
  • FIG. 8 is a block diagram illustrating an example of HE-SIG-B.
  • FIG. 9 shows an example of a trigger frame.
  • FIG 11 shows an example of subfields included in individual user information fields.
  • FIG. 12 is a conceptual diagram illustrating a triggering method of UL MU transmission according to the present embodiment.
  • FIG. 13 is a conceptual diagram illustrating a triggering method of UL MU transmission according to another embodiment.
  • FIG. 14 shows an example of a MAC frame for a power save operation according to the present embodiment.
  • FIG. 15 shows an exemplary format of a TWT information subfield according to the present embodiment.
  • 16 and 17 illustrate an operation of a power saving mode using an M-STA BA frame according to another exemplary embodiment.
  • FIG. 18 illustrates an operation of a power saving mode using an M-STA BA frame according to another embodiment.
  • FIG. 19 is a flowchart illustrating a method for power management in a WLAN system according to an exemplary embodiment.
  • 20 is a block diagram illustrating a wireless terminal to which an embodiment can be applied.
  • FIG. 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.
  • IEEE Institute of Electrical and Electronic Engineers
  • 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.
  • APs access points
  • STAs stations
  • the first BSS 100 may include a first AP 110 and one first STA 100-1 coupled with the first AP 110.
  • the second BSS 105 may include a second AP 130 and one or more STAs 105-1 and 105-2 coupled with the second AP 130.
  • the infrastructure BSS 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 110 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).
  • 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.
  • FIG. 1B is a conceptual diagram illustrating an independent BSS.
  • 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).
  • BSS basic service set
  • 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.
  • MAC medium access control
  • IEEE Institute of Electrical and Electronics Engineers 802.11
  • 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.
  • WTRU wireless transmit / receive unit
  • UE user equipment
  • MS mobile station
  • FIG. 2 is a diagram illustrating an example of a PPDU used in the IEEE standard.
  • PPDUs PHY protocol data units
  • LTF and STF fields included training signals
  • SIG-A and SIG-B included control information for the receiving station
  • data fields included user data corresponding to the PSDU.
  • This embodiment proposes an improved technique for the signal (or control information field) used for the data field of the PPDU.
  • the signal proposed in this embodiment may be applied on a high efficiency PPDU (HE PPDU) according to the IEEE 802.11ax standard. That is, the signals to be improved in the present embodiment may be HE-SIG-A and / or HE-SIG-B included in the HE PPDU. Each of HE-SIG-A and HE-SIG-B may also be represented as SIG-A or SIG-B.
  • the improved signal proposed by this embodiment is not necessarily limited to the HE-SIG-A and / or HE-SIG-B standard, and controls / control of various names including control information in a wireless communication system for transmitting user data. Applicable to data fields.
  • FIG. 3 is a diagram illustrating an example of a HE PPDU.
  • the control information field proposed in this embodiment may be HE-SIG-B included in the HE PPDU as shown in FIG. 3.
  • the HE PPDU according to FIG. 3 is an example of a PPDU for multiple users.
  • the HE-SIG-B may be included only for the multi-user, and the HE-SIG-B may be omitted in the PPDU for the single user.
  • a HE-PPDU for a multiple user includes a legacy-short training field (L-STF), a legacy-long training field (L-LTF), a legacy-signal (L-SIG), High efficiency-signal A (HE-SIG-A), high efficiency-signal-B (HE-SIG-B), high efficiency-short training field (HE-STF), high efficiency-long training field (HE-LTF)
  • L-STF legacy-short training field
  • L-SIG-A High efficiency-signal A
  • HE-SIG-B high efficiency-signal-B
  • HE-STF high efficiency-long training field
  • HE-LTF High efficiency-long training field
  • 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.). Detailed description of each field of FIG. 3 will be described later.
  • resource units (RUs) used on a 20 MHz band.
  • resource units (RUs) corresponding to different numbers of tones may be used to configure some fields of the HE-PPDU.
  • resources may be allocated in units of RUs shown for HE-STF, HE-LTF, and data fields.
  • 26-units ie, units corresponding to 26 tones
  • Six tones may be used as the guard band in the leftmost band of the 20 MHz band, and five tones may be used as the guard band in the rightmost band of the 20 MHz band.
  • seven DC tones are inserted into the center band, that is, the DC band, and 26-units corresponding to each of the 13 tones may exist to the left and right of the DC band.
  • other bands may be allocated 26-unit, 52-unit, 106-unit. Each unit can be assigned for a receiving station, i. E. A user.
  • the RU arrangement of FIG. 4 is utilized not only for the situation for a plurality of users (MU), but also for the situation for a single user (SU), in which case one 242-unit is shown as shown at the bottom of FIG. It is possible to use and in this case three DC tones can be inserted.
  • FIG. 5 is a diagram illustrating an arrangement of resource units (RUs) used on a 40 MHz band.
  • the example of FIG. 5 may also use 26-RU, 52-RU, 106-RU, 242-RU, 484-RU, and the like.
  • five DC tones can be inserted at the center frequency, 12 tones are used as the guard band in the leftmost band of the 40 MHz band, and 11 tones are in the rightmost band of the 40 MHz band. This guard band can be used.
  • the 484-RU may be used when used for a single user. Meanwhile, the specific number of RUs may be changed as in the example of FIG. 4.
  • FIG. 6 is a diagram illustrating an arrangement of resource units (RUs) used on an 80 MHz band.
  • the example of FIG. 6 may also use 26-RU, 52-RU, 106-RU, 242-RU, 484-RU, 996-RU, and the like. have.
  • seven or five DC tones can be inserted at the center frequency, and 12 tones are used as the guard band in the leftmost band of the 80 MHz band, and in the rightmost band of the 80 MHz band. Eleven tones can be used as guard bands.
  • 996-RU may be used when used for a single user. Meanwhile, the specific number of RUs may be changed as in the example of FIGS. 4 and 5.
  • FIG. 7 is a diagram illustrating another example of the HE-PPDU.
  • FIG. 7 is another example illustrating the HE-PPDU block of FIG. 3 in terms of frequency.
  • the illustrated L-STF 700 may include a short training orthogonal frequency division multiplexing symbol.
  • the L-STF 700 includes frame detection, automatic gain control (AGC), diversity detection, and coarse frequency / time synchronization.
  • AGC automatic gain control
  • the L-LTF 710 may include a long training orthogonal frequency division multiplexing symbol.
  • the L-LTF 710 may be used for fine frequency / time synchronization and channel prediction.
  • L-SIG 720 may be used to transmit control information.
  • the L-SIG 720 may include information about a data rate and a data length.
  • the L-SIG 720 may be repeatedly transmitted. That is, the L-SIG 720 may be configured in a repeating format (for example, may be referred to as an R-LSIG).
  • the HE-SIG-A 730 may include control information common to the receiving station.
  • the HE-SIG-A 730 may include 1) a DL / UL indicator, 2) a BSS color field which is an identifier of a BSS, 3) a field indicating a remaining time of a current TXOP interval, 4) 20, Bandwidth field indicating 40, 80, 160, 80 + 80 Mhz, 5) Field indicating MCS scheme applied to HE-SIG-B, 6) HE-SIB-B is dual subcarrier modulation for MCS ( field indicating whether it is modulated by dual subcarrier modulation), 7) field indicating the number of symbols used for HE-SIG-B, and 8) indicating whether HE-SIG-B is generated over the entire band.
  • The. Specific fields of the HE-SIG-A may be added or omitted. In addition, some fields may be added or omitted in other environments where the HE-SIG-A is not a multi-user (MU) environment.
  • MU multi-user
  • the HE-SIG-B 740 may be included only when it is a PPDU for a multi-user (MU) as described above. Basically, the HE-SIG-A 730 or the HE-SIG-B 740 may include resource allocation information (or virtual resource allocation information) for at least one receiving STA.
  • the HE-SIG-B 740 is described in more detail with reference to FIG. 8 described below.
  • the previous field of the HE-SIG-B 740 on the MU PPDU may be transmitted in duplicated form.
  • the HE-SIG-B 740 transmitted in a part of the frequency band is the frequency band (ie, the fourth frequency band) of the Control information for a data field and a data field of another frequency band (eg, the second frequency band) except for the corresponding frequency band may be included.
  • the HE-SIG-B 740 of a specific frequency band (eg, the second frequency band) duplicates the HE-SIG-B 740 of another frequency band (eg, the fourth frequency band). It can be one format.
  • the HE-SIG-B 740 may be transmitted in an encoded form on all transmission resources.
  • the field after the HE-SIG-B 740 may include individual information for each receiving STA that receives the PPDU.
  • the HE-STF 750 may be used to improve automatic gain control estimation in a multiple input multiple output (MIMO) environment or an orthogonal frequency-division multiple access (OFDMA) environment.
  • MIMO multiple input multiple output
  • OFDMA orthogonal frequency-division multiple access
  • the HE-LTF 760 may be used to estimate a channel in a MIMO environment or an OFDMA environment.
  • the size of the FFT / IFFT applied to the field after the HE-STF 750 and the HE-STF 750 may be different from the size of the FFT / IFFT applied to the field before the HE-STF 750.
  • the size of the FFT / IFFT applied to the fields after the HE-STF 750 and the HE-STF 750 may be four times larger than the size of the IFFT applied to the field before the HE-STF 750.
  • a field of s is called a first field
  • at least one of the data field 770, the HE-STF 750, and the HE-LTF 760 may be referred to as a second field.
  • the first field may include a field related to a legacy system
  • the second field may include a field related to a HE system.
  • 256 FFT / IFFT is applied for a bandwidth of 20 MHz
  • 512 FFT / IFFT is applied for a bandwidth of 40 MHz
  • 1024 FFT / IFFT is applied for a bandwidth of 80 MHz
  • 2048 FFT for a bandwidth of 160 MHz continuous or discontinuous 160 MHz.
  • / IFFT can be applied.
  • spacing may be applied to a subcarrier having a size of 312.5 kHz, which is a conventional subcarrier spacing, and space may be applied to a subcarrier having a size of 78.125 kHz, as a second field of the HE PPDU.
  • the length of an OFDM symbol may be a value obtained by adding a length of a guard interval (GI) to an IDFT / DFT length.
  • the length of the GI can be various values such as 0.4 ⁇ s, 0.8 ⁇ s, 1.6 ⁇ s, 2.4 ⁇ s, 3.2 ⁇ s.
  • the frequency band used by the first field and the frequency band used by the second field are represented in FIG. 7, they may not exactly coincide with each other.
  • the main band of the first field L-STF, L-LTF, L-SIG, HE-SIG-A, HE-SIG-B
  • HE-STF the main band of the first field
  • HE-LTF, Data the second field
  • the interface may be inconsistent. 4 to 6, since a plurality of null subcarriers, DC tones, guard tones, etc. are inserted in the process of arranging the RU, it may be difficult to accurately match the interface.
  • the user may receive the HE-SIG-A 730 and may be instructed to receive the downlink PPDU based on the HE-SIG-A 730.
  • the STA may perform decoding based on the changed FFT size from the field after the HE-STF 750 and the HE-STF 750.
  • the STA may stop decoding and configure a network allocation vector (NAV).
  • NAV network allocation vector
  • the cyclic prefix (CP) of the HE-STF 750 may have a larger size than the CP of another field, and during this CP period, the STA may perform decoding on the downlink PPDU by changing the FFT size.
  • data (or frame) transmitted from the AP to the STA is called downlink data (or downlink frame), and data (or frame) transmitted from the STA to the AP is called uplink data (or uplink frame).
  • downlink data or downlink frame
  • uplink data or uplink frame
  • the transmission from the AP to the STA may be expressed in terms of downlink transmission
  • the transmission from the STA to the AP may be expressed as uplink transmission.
  • each of the PHY protocol data units (PPDUs), frames, and data transmitted through downlink transmission may be expressed in terms of a downlink PPDU, a downlink frame, and downlink data.
  • the PPDU may be a data unit including a PPDU header and a physical layer service data unit (PSDU) (or MAC protocol data unit (MPDU)).
  • PSDU physical layer service data unit
  • MPDU MAC protocol data unit
  • the PPDU header may include a PHY header and a PHY preamble
  • the PSDU (or MPDU) may be a data unit including a frame (or an information unit of a MAC layer) or indicating a frame.
  • the PHY header may be referred to as a physical layer convergence protocol (PLCP) header in another term
  • the PHY preamble may be expressed as a PLCP preamble in another term.
  • each of the PPDUs, frames, and data transmitted through uplink transmission may be represented by the term uplink PPDU, uplink frame, and uplink data.
  • the entire bandwidth may be used for downlink transmission to one STA and uplink transmission of one STA based on single (or single) -orthogonal frequency division multiplexing (SUDM) transmission.
  • the AP may perform downlink (DL) multi-user (MU) transmission based on MU MIMO (multiple input multiple output), and such transmission is DL MU MIMO transmission. It can be expressed as.
  • orthogonal frequency division multiple access (OFDMA) based transmission method is preferably supported for uplink transmission and downlink transmission. That is, uplink / downlink communication may be performed by allocating data units (eg, RUs) corresponding to different frequency resources to the user.
  • the AP performs OFDMA.
  • DL MU transmission may be performed based on the above, and such transmission may be expressed in terms of DL MU OFDMA transmission.
  • the AP may transmit downlink data (or downlink frame, downlink PPDU) to each of the plurality of STAs through the plurality of frequency resources on the overlapped time resources.
  • the plurality of frequency resources may be a plurality of subbands (or subchannels) or a plurality of resource units (RUs).
  • DL MU OFDMA transmission can be used with DL MU MIMO transmission. For example, DL MU MIMO transmission based on a plurality of space-time streams (or spatial streams) is performed on a specific subband (or subchannel) allocated for DL MU OFDMA transmission. Can be.
  • UL MU transmission uplink multi-user transmission
  • a plurality of STAs transmit data to the AP on the same time resource.
  • Uplink transmission on the overlapped time resource by each of the plurality of STAs may be performed in the frequency domain or the spatial domain.
  • different frequency resources may be allocated as uplink transmission resources for each of the plurality of STAs based on OFDMA.
  • the different frequency resources may be different subbands (or subchannels) or different resource units (RUs).
  • Each of the plurality of STAs may transmit uplink data to the AP through different allocated frequency resources.
  • the transmission method through these different frequency resources may be represented by the term UL MU OFDMA transmission method.
  • each of the plurality of STAs When uplink transmission by each of the plurality of STAs is performed in the spatial domain, different space-time streams (or spatial streams) are allocated to each of the plurality of STAs, and each of the plurality of STAs transmits uplink data through different space-time streams. Can transmit to the AP.
  • the transmission method through these different spatial streams may be represented by the term UL MU MIMO transmission method.
  • the UL MU OFDMA transmission and the UL MU MIMO transmission may be performed together.
  • UL MU MIMO transmission based on a plurality of space-time streams (or spatial streams) may be performed on a specific subband (or subchannel) allocated for UL MU OFDMA transmission.
  • a multi-channel allocation method was used to allocate a wider bandwidth (for example, a bandwidth exceeding 20 MHz) to one UE.
  • the multi-channel may include a plurality of 20 MHz channels when one channel unit is 20 MHz.
  • a primary channel rule is used to allocate a wide bandwidth to the terminal. If the primary channel rule is used, there is a constraint for allocating a wide bandwidth to the terminal.
  • the primary channel rule when a secondary channel adjacent to the primary channel is used in an overlapped BSS (OBSS) and 'busy', the STA may use the remaining channels except the primary channel. Can't.
  • OBSS overlapped BSS
  • the STA can transmit the frame only through the primary channel, thereby being limited to the transmission of the frame through the multi-channel. That is, the primary channel rule used for multi-channel allocation in the existing WLAN system may be a big limitation in obtaining high throughput by operating a wide bandwidth in the current WLAN environment where there are not many OBSS.
  • a WLAN system supporting the OFDMA technology supporting the OFDMA technology. That is, the above-described OFDMA technique is applicable to at least one of downlink and uplink.
  • the above-described MU-MIMO technique may be additionally applied to at least one of downlink and uplink.
  • OFDMA technology is used, a plurality of terminals may be used simultaneously instead of one terminal without using a primary channel rule. Therefore, wide bandwidth operation is possible, and the efficiency of the operation of radio resources can be improved.
  • the AP when uplink transmission by each of a plurality of STAs (eg, non-AP STAs) is performed in the frequency domain, the AP has different frequency resources for each of the plurality of STAs based on OFDMA. It may be allocated as a link transmission resource. In addition, as described above, different frequency resources may be different subbands (or subchannels) or different resource units (RUs).
  • OFDMA orthogonal frequency division multiple access
  • Different frequency resources for each of the plurality of STAs may be indicated through a trigger frame.
  • FIG. 8 is a block diagram illustrating an example of HE-SIG-B.
  • the HE-SIG-B field includes a common field at the beginning, and the common field can be encoded separately from the following field. That is, as shown in FIG. 8, the HE-SIG-B field may include a common field including common control information and a user-specific field including user-specific control information.
  • the common field may include a corresponding CRC field and may be coded into one BCC block. Subsequent user-specific fields may be coded into one BCC block, including a "user-specific field" for two users (2 users), a CRC field corresponding thereto, and the like, as shown.
  • the trigger frame of FIG. 9 allocates resources for uplink multiple-user transmission and can be transmitted from the AP.
  • the trigger frame may consist of a MAC frame and may be included in a PPDU. For example, it may be transmitted through the PPDU shown in FIG. 3, through the legacy PPDU shown in FIG. 2, or through a PPDU specifically designed for the trigger frame. If transmitted through the PPDU of FIG. 3, the trigger frame may be included in the illustrated data field.
  • Each field shown in FIG. 9 may be partially omitted, and another field may be added. In addition, the length of each field may be varied as shown.
  • the frame control field 910 of FIG. 9 includes information about the version of the MAC protocol and other additional control information, and the duration field 920 includes time information for setting the NAV described below.
  • Information about an identifier (eg, AID) of the terminal may be included.
  • the RA field 930 includes address information of the receiving STA of the corresponding trigger frame and may be omitted as necessary.
  • the TA field 940 includes address information of an STA (for example, an AP) that transmits a corresponding trigger frame, and the common information field 950 is common to be applied to a receiving STA that receives the corresponding trigger frame. Contains control information
  • per user information fields 960 # 1 to 960 # N corresponding to the number of receiving STAs receiving the trigger frame of FIG. 9.
  • the individual user information field may be referred to as a "RU assignment field.”
  • the trigger frame of FIG. 9 may include a padding field 970 and a frame check sequence field 980.
  • Each of the per user information fields 960 # 1 to 960 # N shown in FIG. 9 preferably includes a plurality of subfields.
  • FIG. 10 shows an example of a common information field. Some of the subfields of FIG. 10 may be omitted, and other subfields may be added. In addition, the length of each illustrated subfield may be modified.
  • the illustrated length field 1010 has the same value as the length field of the L-SIG field of the uplink PPDU transmitted corresponding to the trigger frame, and the length field of the L-SIG field of the uplink PPDU indicates the length of the uplink PPDU.
  • the length field 1010 of the trigger frame may be used to indicate the length of the corresponding uplink PPDU.
  • the cascade indicator field 1020 indicates whether a cascade operation is performed.
  • the cascade operation means that downlink MU transmission and uplink MU transmission are performed together in the same TXOP. That is, after downlink MU transmission is performed, it means that uplink MU transmission is performed after a predetermined time (eg, SIFS).
  • a predetermined time eg, SIFS.
  • only one transmitting device (eg, AP) for downlink communication may exist, and a plurality of transmitting devices (eg, non-AP) for uplink communication may exist.
  • the CS request field 1030 indicates whether the state of the radio medium, the NAV, or the like should be considered in a situation in which the receiving apparatus receiving the trigger frame transmits the corresponding uplink PPDU.
  • the HE-SIG-A information field 1040 may include information for controlling the content of the SIG-A field (ie, the HE-SIG-A field) of the uplink PPDU transmitted in response to the corresponding trigger frame.
  • the CP and LTF type field 1050 may include information about the length of the LTF and the CP length of the uplink PPDU transmitted in response to the corresponding trigger frame.
  • the trigger type field 1060 may indicate the purpose for which the corresponding trigger frame is used, for example, normal triggering, triggering for beamforming, a request for Block ACK / NACK, and the like.
  • FIG. 11 illustrates an example of subfields included in an individual user information field. Some of the subfields of FIG. 11 may be omitted, and other subfields may be added. In addition, the length of each illustrated subfield may be modified.
  • the user identifier field 1110 of FIG. 11 indicates an identifier of an STA (ie, a receiving STA) to which per user information corresponds.
  • An example of the identifier may be all or part of an AID. have.
  • the RU Allocation field 1120 may be included. That is, when the receiving STA identified by the user identifier field 1110 transmits an uplink PPDU in response to the trigger frame of FIG. 9, the corresponding uplink PPDU through the RU indicated by the RU Allocation field 1120. Send.
  • the RU indicated by the RU Allocation field 1120 preferably indicates the RUs shown in FIGS. 4, 5, and 6.
  • the subfield of FIG. 11 may include a coding type field 1130.
  • the coding type field 1130 may indicate a coding type of an uplink PPDU transmitted in response to the trigger frame of FIG. 9. For example, when BCC coding is applied to the uplink PPDU, the coding type field 1130 is set to '1', and when LDPC coding is applied, the coding type field 1130 is set to '0'. Can be.
  • the subfield of FIG. 11 may include an MCS field 1140.
  • the MCS field 1140 may indicate an MCS scheme applied to an uplink PPDU transmitted in response to the trigger frame of FIG. 9. For example, when BCC coding is applied to the uplink PPDU, the coding type field 1130 is set to '1', and when LDPC coding is applied, the coding type field 1130 is set to '0'. Can be.
  • FIG. 12 is a conceptual diagram illustrating a triggering method of UL MU transmission according to the present embodiment.
  • the horizontal axis of the AP 1200 represents a time t
  • the vertical axis represents the existence of a frame transmitted in terms of frequency.
  • the horizontal axis of the first STA 1210 represents time t1
  • the vertical axis represents the existence of a frame transmitted in terms of frequency.
  • the horizontal axis of the second STA 1220 represents time t2
  • the vertical axis represents the existence of a frame transmitted in terms of frequency.
  • the AP 1200 triggers transmission of a plurality of uplink frames (or UL MU PDU protocol data units (UL MU PPDUs) 1212, 1216) by a plurality of STAs 1210, 1220.
  • a trigger frame 1210 may be transmitted.
  • the AP 1200 may transmit information on the transmission time of the trigger frame 1210 to the plurality of STAs 1210 and 1220.
  • the plurality of STAs 1210 and 1220 may receive the trigger frame 210 based on the information on the transmission time of the trigger frame 1210.
  • the plurality of STAs 1210 and 1220 may perform UL MU transmission based on the trigger frame 1210 transmitted by the AP 1200.
  • the plurality of STAs 1210 and 1220 may transmit the UL MU PPDUs 1215 and 1216 to the trigger frame 1210 received from the AP 1200.
  • the plurality of STAs 1210 and 1220 operating in the power save mode switch the trigger frame 1210 from the doze state to the awake state based on the information on the transmission time of the trigger frame 1210. Can be received.
  • the dose state may be a state in which transmission / reception of a frame by the STA is not performed for power saving.
  • the awake state may be a state in which transmission / reception of a frame by the STA is performed.
  • the trigger frame 1210 may include identification information of a plurality of STAs for transmitting the UL MU PPDU and information about resource units individually allocated to the plurality of STAs for transmitting the UL MU PPDU.
  • the transmission time of the trigger frame 1210 may be referred to as a target transmission time.
  • the information on the target transmission time may be transmitted based on a target wakeup time element.
  • TargetWakeTime (hereinafter, referred to as 'TWT') may be a time resource that is set to manage activities in the BSS of the STA. According to the configuration of the target wake time (TWT), a plurality of STAs may operate at different times. Accordingly, contention between each STA may be reduced.
  • TWT target wake time
  • the target wake time may be defined to minimize the operation of the awake state of each STA.
  • An STA requesting a target wake time (TWT) may be referred to as a TWT request STA.
  • An STA performing communication with a TWT requesting STA based on a request of a target wake time (TWT) may be referred to as a TWT responding STA.
  • the TWT request STA may be a user STA and the TWT response STA may be an AP.
  • a TWT element transmitted by an STA that is a TWT request STA may be represented by a TWT request element 1200.
  • the TWT element transmitted by the AP, which is a TWT response STA, may be represented by a TWT response element 1205.
  • the TWT request element 1200 and the TWT response element 1205 may be divided based on a specific indicator (or field) in the TWT element.
  • the TWT request element 1200 and the TWT response element 1205 may be in the same format or in different formats with some of the fields included.
  • the first STA 1210 transmits a TWT pattern (or TWT parameter) to the AP through the TWT request element 1200 to receive a scheduled trigger frame from the AP 1200.
  • a TWT pattern (or TWT parameter) may be information determined based on a UL traffic pattern or a quality of service (QoS) request of the STA 1210.
  • QoS quality of service
  • the TWT pattern may be a periodic pattern or an aperiodic pattern as an operation pattern for communication between the STA and the AP.
  • the request type field of the TWT request element 1200 is set to a predefined bit value (eg, '1')
  • the TWT request element 1200 may transmit a target for a trigger frame. It can be used to request in advance the transmission of information about time to the AP.
  • the TWT request element 1200 may be used to request a TWT for receiving a trigger frame.
  • the trigger is performed using 1 bit of the reserved bits 1255 of the control field 1230 of the TWT request element 1200.
  • Information on the target transmission time of the frame 210 may be requested to the AP.
  • the information on the target transmission time of the trigger frame 1210 may be received through the TWT response element 1205 of the beacon frame transmitted by the AP.
  • the STA transmits information on the number of TBTTs or TBTT intervals to perform an operation to the AP by using the preserved bits 1255 of the control field 1230 to transmit the TWT response element 1205 of the beacon frame for a specific time interval. Through the transmission of information on the target transmission time of the trigger frame 1210 may be requested.
  • the STA may transmit information on the number of TBTTs to receive information on the target transmission time of the trigger frame 1210 using the preserved bit 1255 of the control field 1230 to the AP.
  • the AP may transmit information on the target transmission time for the trigger frame 1210 through the TWT response element 1205 of the beacon frame during a time period corresponding to the number of TBTTs set by the STA.
  • the STA may transmit the information on the TBTT interval to receive the information on the target transmission time of the trigger frame to the AP using the preserved bit 1255.
  • the AP may transmit information on the target transmission time for the trigger frame 1210 during the time period corresponding to the TBTT interval set by the STA.
  • the information on the target transmission time for the trigger frame 1210 may be transmitted through the TWT response element 205 of the beacon frame.
  • An STA operating in a power save mode receives a frame (or TWT request frame) including a TWT request element to schedule an AP (or a TWT response STA or TWT).
  • TWT scheduling STA STA
  • the TWT request frame may include information on the TBTT of the next beacon frame and information on an interval of a sub-sequent beacon frame to be received by the STA.
  • An AP which is an STA that schedules a TWT, may determine an interval between a TBTT of a next beacon frame and a sub-sequent beacon frame to be received by the STA.
  • the TWT request frame (TWT request element 1200) may include the following values. If the TWT command field indicates a proposed TWT or demand TWT, then the TWT request frame 1200 will include the first TBTT information requested in the target wake time (TWT) field. Can be.
  • the target transmission time of the trigger frame may be determined by the STA (or TWT response STA) scheduling the target wake time (TWT).
  • the TWT request frame sent by the TWT request STA may include a target wake time field and other TWT parameters.
  • the TWT request STA may perform the TWT configuration procedure even when the target wake time field proposed by the TWT request frame is not applied.
  • the TWT request STA may not perform the TWT setup procedure when the target wake time field proposed by the TWT request frame is not applied.
  • the TWT request frame 1200 may include a TWT Wake Interval Mantissa field and a TWT Wake Interval Exponent field.
  • the TWT Wake Interval Mentee field and the TWT Wake Interval Component field may include information on the value of the listening interval between successive TBTTs.
  • the TWT wake interval mentee field may include information on a mantissa for determining a target wake interval.
  • the TWT wake interval component field may include information about an exponent value for determining a target wake interval having a base of two.
  • the size of the target wake interval may be determined based on the TWT wake interval mentee x2 (TWT wake interval component).
  • a TWT responding STA that receives a TWT request frame (TWT request element) from an STA whose TWT wake interval has the same value as the listening interval of the STA may receive an accept TWT or reject TWT. May respond with a TWT response frame (or TWT response element) indicated by the TWT command field.
  • the accepting TWT may indicate to accept the value of the TWT parameter requested by the TWT requesting STA.
  • the reject TWT may indicate that it does not accept the value of the TWT parameter requested by the TWT requesting STA.
  • the TWT response frame is between the value of the first assigned TBTT within the target wake time field and the consecutive TBTTs indicated based on the TWT wake interval mentee field and the TWT wake interval component field. It may further include information about the value of the listening interval.
  • the TWT requesting STA may remain in a doze state until a timing synchronization function matches the next negotiated TBTT.
  • the TWT request STA may be switched to an awake state to receive a beacon frame transmitted in the negotiated TBTT.
  • the TWT request element 1200 includes an element ID field 1220, a length field 1225, a control field 1230, and a request type field 1235. can do. Subsequent fields may be omitted.
  • the target wake time field 1240 of the TWT request element 1200 may request a TWT request.
  • the element 1200 may be omitted or the value of the target wake time field 1240 may be set to an 'all zero value'.
  • the TWT wake interval field 1250 may be determined in consideration of a QoS pattern of uplink data of the STA.
  • the STA may transmit information on a target wake time to the AP through the TWT request element 1200.
  • the target wake time field 1240 is then transmitted.
  • the STA may include information on which TBTT interval unit of the beacon frame from the beacon frame to the awake mode.
  • the unsolicited trigger indicator may indicate whether to receive the trigger frame 1210 based on the information on the target transmission time for the trigger frame 1210 set by the AP 1200.
  • the unsolicited trigger field 1260 may include an unsolicited trigger indicator indicating whether to receive a trigger frame 1210 according to the target transmission time set by the AP.
  • the AP may request the AP to set the target transmission time of the AP in consideration of the TWT parameter set by the STA. If the unsolicited trigger branch is the second value, it may indicate that the STA will follow the target transmission time based on the TWT parameter set by the AP.
  • the STA may not request transmission of the trigger frame 1210 of the AP 1200 by setting a separate TWT parameter. That is, when the unsolicited trigger indicator is set to 1, the STA may perform an operation based on the TWT parameter set by the AP.
  • the AP may receive the TWT request element 1200 from the STA.
  • the AP may transmit information on the target transmission time of the trigger frame 1210 through the TWT response element 11205 included in the beacon frame for the STA having UL uplink multi-user (MU) transmission capability.
  • MU uplink multi-user
  • the AP may determine the target wake time field of the TWT response element 1205.
  • the STA may inform the STA about from which beacon frame to which TBTT interval (or listen interval) a beacon frame is received.
  • the STA may enter an awake mode to receive information on the target transmission time of the trigger frame through the beacon frame in units of TBTT interval based on the target wake time field 1240. Can be switched.
  • the AP may transmit a TWT response element in which information about the target wake time field 1240 is omitted.
  • the STA that has received the TWT response element that does not include the target wake time field 1240 may switch to the awake mode to receive information on the target transmission time of the trigger frame from the next beacon frame transmitted.
  • the STA may transmit buffer status information instead of information on the target wake time through the target wake time field 1240 of the TWT request element 1200.
  • information on a traffic identifier (TID), buffer status information, or queue size information may be transmitted through 8 octets corresponding to the target wake time field.
  • the AP which receives a traffic identifier (TID), buffer status information, or queue size information through a target wake time field of a TWT request element, uses a STA's buffer information and TWT wake interval information to trigger a UL MU to the STA. Can send
  • the element ID field 1220 may include identification information for indicating that the transmitted information unit is a TWT element.
  • the length field 1225 may include information about the length of the transmitted information unit.
  • the control field 1230 may further include a null data packet (NDP) paging indicator field and a responder power management (PM) mode field.
  • NDP null data packet
  • PM responder power management
  • the NDP paging indicator field may include an NDP paging indicator for indicating whether an NDP paging field exists.
  • the NDP paging field may include information for paging for the STA.
  • the responder PM mode field may include information about the power management mode.
  • the TWT wake interval field 1250 included in the TWT request element 1200 transmitted by the STA may include information about an interval between TWTs.
  • the TWT wake interval field 1250 may be determined based on a quality of service (QoS) pattern of uplink data of the STA.
  • QoS quality of service
  • the STA receiving the beacon frame may be a target beacon transmission time (TBTT) unit (or TBTT interval unit) based on a beacon frame transmitted after several beacon frames are transmitted by the AP through the target wake time field 1240.
  • the system may transition to a low awake state to receive the TWT response element 1205.
  • the TWT response element 1205 may include information about the target transmission time of the trigger frame 1210.
  • the TBTT may be a transmission interval of a beacon frame transmitted by the AP.
  • the AP receiving the TWT request element 1200 from the STA may transmit information on the target transmission time of the trigger frame 1210 through the TWT response element 1205 included in the beacon frame for the STA capable of transmitting UL MU. have.
  • the AP may transmit the TWT response element 1205 in response to the TWT request element 1200 transmitted by the STA to request the target transmission time of the trigger frame 1210.
  • the TWT response element 1205 may include a target wake up time field 1240 and / or a TWT wake interval field 1250.
  • the target wakeup time field 1240 included in the TWT response element 1205 is information on whether the STA receives information on the target transmission time of the trigger frame 1210 through a beacon frame transmitted after several beacon frames. It may include. In other words, the target wakeup time field 1240 may include information on a transmission time of the trigger frame 1210.
  • the TWT wake interval field 1250 may include information on an interval at which the STA is switched to an awake state and receives a beacon frame.
  • the STA receiving the TWT response element 1205 wakes up in a target beacon transmission time (TBTT) interval after a specific beacon frame based on the target wake up time field 1240 and / or the TWT wake interval field 1250. Switch to to receive the beacon frame to obtain information about the target transmission time of the trigger frame 1210.
  • TBTT target beacon transmission time
  • the TWT response element 1205 may not include the target wakeup time field 1240 (or may omit the value of the target wakeup time field 240), and may replace the target wakeup time field 1240.
  • the target wake time field of the TWT request element 1200 is set. 1240 may transmit the buffer status information of the STA instead of the information on the target wake time.
  • the target wake time field 1240 may have a size of 8 octets, and when the unsolicited trigger indicator of the unsolicited trigger field 1260 included in the TWT request element 1200 is set to '1',
  • the 8-octet target wake time field 1240 may include information corresponding to a traffic identifier (TID), a buffer state, or a queue size for uplink data to be transmitted by the STA.
  • TID traffic identifier
  • the TID may include information on characteristics of uplink data buffered in the STA, and the buffer state or queue size information may include information on the size of uplink data buffered in the STA.
  • the AP transmits UL MU transmission of the STA based on the buffer information of the STA received through the target wake time field 1240 included in the TWT request element 1200 and the TWT interval information received through the TWT wake interval field 1240.
  • the trigger frame 1210 may be transmitted.
  • the STA may transmit information about the TWT pattern (or a TWT parameter for determining the TWT) to the AP based on the TWT request element 1200.
  • the TWT pattern may be determined based on the target wake time field 1240, the nominal minimum wake duration field 1245, and the TWT wake interval field 1250 as a pattern of the TWT.
  • the STA may request TWT or information on the target transmission time of the trigger frame 1210 by setting the reserved bit of the request type field of the TWT request element 1200 to 1 to the AP.
  • the STA uses the remaining 5 bits of the conserved field of the control field 1230 of the TWT request element 1200 to inform the target transmission time of the trigger frame 1210 from the AP using the TWT pattern information set for several TBTTs. Information on whether or not to receive can be transmitted.
  • the STA continues to trigger through the TWT response element 1205 included in the beacon frame until the STA sends a TWT teardown request or other TWT request element (or other TWT parameter) via the TWT request element 1200.
  • Information about the target transmission time of the frame 1210 may also be transmitted.
  • the STA sets the unsolicited trigger field 1260 included in the preserved field (or preserved bit) 1255 of the control field 1230 of the TWT request element 1200 to 1 and sets the TBTT duration field.
  • the TBTT duration field may include information on the duration at which the information on the target transmission time of the trigger frame 1210 (or the TWT response element 1205) is transmitted.
  • the STA sets the unsolicited trigger field 1260 of the control field 1230 of the TWT request element 1200 to 1 and sets the TBTT duration to 3 to trigger through three beacon frames, including the next beacon frame.
  • the AP may request to transmit information on the target transmission time of the frame 1210.
  • the AP transmits a TWT response element 1205 including information on the target transmission time of the trigger frame 1210 of the STA based on the unsolicited trigger field 1260 and the TBTT duration field of the TWT request element 1200 indicated by the STA. It is possible to know whether or not to receive a beacon frame including a), and based on this can transmit a beacon frame including a TWT response element 1205 including information on the target transmission time of the trigger frame 1210. .
  • the reserved bit of the request type field 1235 may be set to '1'.
  • the STA may transmit by setting the MSB bit of the control field 1230 of the TWT request element 1200 to '1'. Based on the subsequent bits (for example, 5 bits), the STA may inform which TBTT interval to receive information about the target transmission time from the AP.
  • the STA may inform the AP to receive a beacon frame at an interval equal to three times the TBTT interval.
  • Setting the TBTT interval to 3 may mean that the STA periodically receives only one of three consecutive beacon frames.
  • the STA may indicate that it wants to receive information about the target transmission time of the trigger frame through every beacon frame by setting the unsolicited trigger indicator of the control field of the TWT request element to 1 and setting the TBTT interval to 1. have.
  • the AP receiving the TWT request element can know which beacon frame the STA receives based on the TWT request element transmitted by the STA, and the AP can determine target transmission information of the trigger frame for UL MU transmission of the STA. It can transmit through the beacon frame.
  • the STA may request the AP to receive information on the target transmission time of the trigger frame through the beacon frame transmitted during the specific TBTT period through the TWT request element 1200.
  • the AP may configure a TWT for receiving the trigger frame 1210 to the STA through the TWT response element 1205 of the beacon frame.
  • the AP may set a TWT for the STA based on the TWT parameter included in the TWT request element 1200 transmitted by the STA, without considering the TWT parameter included in the TWT request element 1200 transmitted by the STA.
  • TWT for STA may be configured.
  • the AP may inform the transmission of the target transmission time information of the trigger frame 1210 through the beacon frame of the AP based on the unsolicited trigger field included in the TWT response element 1205 and the information on the TBTT interval / TBTT duration. .
  • the AP may omit specific subfields of the TWT response element 1205 included in the beacon frame and transmit.
  • the TWT response element 1205 may include only an element ID field 1220, a length field 1225, a control field 1230, a request type field 1235, and no subsequent fields.
  • the AP transmits a TWT for receiving the trigger frame 1210 to the STA through the TWT response element 1205. Can be set In addition, the AP may determine whether to support transmission of an uplink frame based on an unsolicited trigger frame of the STA and transmit information on the TWT to the STA according to the above-described method.
  • the TWT request element 1200 may be expressed in terms of an uplink transmission configuration request element, and the TWT response element 1205 may be an uplink transmission configuration response element.
  • the TWT parameter for configuring the TWT included in the TWT request element 1200 is an uplink transmission setup request parameter
  • the TWT parameter for configuring the TWT included in the TWT response element 1205 is an uplink transmission setup response parameter. Can also be expressed.
  • the preserved field of the control field of the TWT element is used but the use of the preserved field is one example.
  • the above-described operation between the STA and the AP may be performed through a TWT element of another format or an information element for transmitting information on a target transmission time of a newly defined trigger frame, which will be described later.
  • the newly defined TWT request element may include a trigger frame indicator. If the trigger frame indicator of the newly defined TWT request element is set to '1', the MSB of the nominal minimum wake duration field of the TWT request element is not supported (or unsolicited mode). mode) can be used as an indicator indicating whether or not). If the MSB in the nominal minimum wake duration field is set to 1 to indicate support for unsolicited triggers (or support for unsolicit mode), the remaining bits included in the nominal minimum wake duration field are nominal minimum It may include information on the wake duration.
  • the MSB in the nominal minimum wake duration field is set to 0 and does not indicate support for unsolicited triggers (or support for unsolicited mode)
  • the remaining bits included in the nominal minimum wake duration field are the TBTT duration / TBTT interval. It may include information about.
  • Information on the TBTT duration / TBTT interval may be transmitted using all of the fields of.
  • a unit of a target wake time or a TWT wake interval mantissa field and / or a TWT wake interval exponent field indicates a TBTT unit. May be set.
  • this method certain fields in the TWT response element may be omitted or changed to use fewer bits. Therefore, the overhead of data for the AP to transmit information on the target transmission time for the trigger frame through the beacon frame can be reduced.
  • the AP When the unsolicit mode is set, which informs the target transmission time for the trigger frame between the AP and the STA through the beacon frame, the AP is configured for the trigger frame to be allocated for the STA during TBTT through the beacon frame. Information related to the target transmission time may be transmitted.
  • operations similar to the above-described operations may be performed by the STA and the AP by using a triggered indicator and an unsolicited trigger indicator.
  • the STA sets the triggered bit of the TWT request element to '1' and sets the unsolicited trigger bit (or the response PM mode bit) to 1 to wake up every TWT wake interval to obtain a beacon frame from the AP. It can be informed to receive the information on the target transmission time of the trigger frame.
  • the TWT wake interval may be set using at least one of a TWT wake interval mentee field and a TWT wake interval component field of the TWT request element.
  • a TBTT interval or a listening interval for the STA to receive a beacon frame may be expressed based on the TWT wake interval mentee field and the TWT wake interval component.
  • the unit of the TWT wake interval field may be defined as a beacon interval unit.
  • the AP receiving the TWT request element may respond to the TWT request requested by the STA through the TWT response element. If the AP supports the unsolicited trigger method for the STA, the AP sets the triggered bit to 1 and the unsolicited trigger bit (or response PM mode bit) to 1 to transmit. Can be. In this case, the AP may transmit information on the transmission time of the beacon frame for starting the unsolicited trigger method for the STA through the target wake time field of the TWT response element, and transmit the STA through the TWT wake interval field of the TWT response element. The interval information of the beacon frame transmitting the target transmission time of the trigger frame may be transmitted.
  • the STA may receive a beacon frame transmitted to a specific TBTT based on the target wake time field / TWT wake interval field based on the information included in the TWT response element. Thereafter, the STA may switch to the awake mode and receive the beacon frame at the transmission time (or TBTT) of the beacon frame including information on the target transmission time of the trigger frame transmitted by the AP. As such, information on the target transmission time of the trigger frame transmitted by the AP to the STA may be transmitted through the beacon frame.
  • a reserved bit of a control field is used as a triggered indicator (or a triggered bit) and an unsolicited trigger indicator.
  • This embodiment may be reused as an indicator (or triggered bit) and an unsolicited trigger indicator in which the preserved bit of the response PM mode bit or request type field or the bit of another field is triggered as an example.
  • the command type indicated by the TWT setting command field included in the request type field of the TWT response element is TWT Grouping, Accept TWT, Alternate TWT (Alternate TWT). And the like.
  • the TWT response element may include power for grouping for operating a plurality of STAs operating in the power save mode as an unrequested mode as a group.
  • the plurality of STAs operating in the save mode may include information on a transmission time of a start beacon frame to be monitored and information on a transmission interval of another beacon frame transmitted based on the start beacon frame.
  • the transmission interval of the beacon frame may be set equal to the reception interval of the STA.
  • FIG. 13 is a conceptual diagram illustrating a triggering method of UL MU transmission according to another embodiment.
  • a method for requesting information on a target transmission time of a trigger frame and receiving information on a target transmission time is disclosed based on a TWT element of another format.
  • the TWT element is a TWT response element, information included in each field included in the TWT element is disclosed.
  • the preserved field of the control field 1320 of the TWT request element 1300 includes a trigger frame indicator field 1345, a trigger frame-random access indicator field (TF-R). 1350, TF indicator field (or scheduled indicator field TF-S) 1355, group indicator field 1360, wake duration indicator field 1365, wake It may include a wake interval indicator field 1370.
  • TF-R trigger frame-random access indicator field
  • TF indicator field or scheduled indicator field TF-S
  • group indicator field 1360 group indicator field 1360
  • wake duration indicator field 1365 wake It may include a wake interval indicator field 1370.
  • the trigger frame indicator field 1345 may include a trigger frame indicator indicating that information transmitted through the TWT element is information related to transmission of the trigger frame. For example, when the trigger frame indicator is 1, the transmitted information transmitted through the TWT element is information related to the transmission of the trigger frame, and the field included in the TWT element conveys information related to the transmission of the predefined trigger frame. It can be indicated that it is used in a predefined format for.
  • the TF-R indicator field 1350 is a TF-R indicator for indicating whether a trigger frame for random access is transmitted at a time indicated by a trigger target wake time field included in a TWT response element transmitted by an AP. It may include. When the TF-R indicator is set to 1, it may be indicated that the trigger frame 1310 for random access is transmitted at the target wake time indicated by the target wake time field 1325. Conversely, when the TF-R indicator is set to 0, it may be indicated that the trigger frame 1310 for random access is not transmitted at the target wake time indicated by the target wake time field 1325.
  • an unassociated STA or an associated STA that wants to perform random access is triggered at a target wake time. 1310 may be determined whether to switch to the awake state to receive.
  • the TF-R indicator field 1350 may be omitted. For example, when both the STA AID or the group ID are 0, transmission of the trigger frame 1300 for random access may be indicated and the TF-R indicator field 1350 may be omitted.
  • the TF indicator field (or TF-S (scheduled) indicator field) 1355 is a trigger frame 1310 for scheduled access at the target wake time included in the TWT response element 1305 sent by the AP. It may include a TF indicator (or TF-S indicator) indicating whether or not the transmission.
  • the scheduled access may indicate only uplink transmission of at least one STA scheduled by the AP.
  • transmission of the trigger frame 1310 for scheduled access of the STA may be indicated at the target wake time, and conversely, when the TF indicator is set to 0, the target wake It may be indicated that the trigger frame 1310 for scheduled access at time is not transmitted.
  • the STA ID / Group ID related fields 1375 and 1380 which are fields after the target wake time field 1325.
  • Transmission of the nominal minimum wake duration field 1335 and the TWT wake interval field 1340 may be omitted.
  • the group indicator field 1360 indicates whether the STA to receive the trigger frame 1310 is indicated by individual identification information (AID, partial association identifier (PAID), or MAC address) or by group identifier (group identifier) in units of groups. It may include a indicating group indicator. For example, if the group indicator is '1', the STA is to receive a trigger frame based on the group ID, and if the group indicator is '0', the STA is assigned an individual STA ID (AID, PAID, MAC address, etc.). An STA to receive a trigger frame may be indicated based on the result.
  • AID individual identification information
  • PAID partial association identifier
  • group identifier group identifier
  • the wake duration indicator field 1365 may include a wake duration indicator for instructing the STA whether to set a duration for switching to the awake state at the target transmission time indicated by the target wake time field and maintaining the awake state.
  • the AP when the wake duration indicator is set to '1', the AP is configured to switch the STA into the awake state at the target transmission time based on the nominal minimum wake duration field 1335 included in the TWT response element 1305. Thereafter, the duration maintaining the awake state may be set to the STA.
  • the STA may know whether the nominal minimum wake duration field 1335 is omitted in the TWT response element 1305 transmitted by the AP based on the wake duration indicator.
  • the nominal minimum wake duration field 1335 may be included in the TWT response element 1305.
  • the nominal minimum wake duration field 1335 may not be included in the TWT response element 1305.
  • the STA wakes up for reception of the trigger frame 1310 during the indicated duration based on the nominal minimum wake duration field 1335 when the wake duration indicator of the TWT response element 1305 transmitted by the AP is set to 1. State can be maintained.
  • the STA may switch to the doze state in the awake state. Even when the trigger frame 1310 is transmitted during the indicated duration based on the nominal minimum wake duration field 1335, when the duration ends, the STA may be switched to the doze state in the awake state.
  • the STA maintains the awake state for a predefined (or set) duration to monitor the trigger frame 1310 and monitor the trigger frame 1310. If the reception is not received and the duration has expired, it may be switched to the dose state.
  • the wake interval indicator field 1370 may include a wake interval indicator indicating whether the STA sets a transition interval to an awake state for receiving a trigger frame transmitted by the AP.
  • the AP may periodically transmit the trigger frame 1310 to the STA.
  • the STA may receive the trigger frame 1310 at a first target transmission time, and then periodically switch to an awake state to monitor transmission of the trigger frame 1310.
  • the AP may configure a wake interval for receiving the trigger frame 1310 of the STA.
  • the wake interval indicator may indicate whether a wake interval is set by the AP.
  • Each of the TWT wake interval field 1340 may include a plurality of subfields to include individual information for each of the plurality of STAs.
  • the target wake time field 1325 may include a target wake time for the first STA, a target wake time for the second STA, It may include information on the target wake time for the 3 STA.
  • the target wake time field 1325 may include information on a target transmission time of the trigger frame 1310.
  • the time unit for counting the target wake time may be preset.
  • the information on the set time unit may be previously known to the STA or may be previously received by the STA.
  • the TWT group assignment field 1330 may include information on a STA group that will receive a trigger frame based on the TWT (or operate the same TWT basis).
  • the plurality of STAs included in the STA group indicated by the TWT group assignment field 1330 may be switched to the awake state at the time indicated by the target wake time field 1325 to receive the trigger frame 1310 from the AP. have.
  • all STAs may be switched to the awake mode at the target transmission time for reception of the trigger frame 1310.
  • a trigger frame 1310 transmitted to the STA may be scheduled more dynamically based on the number information field 1375 of the STA and the STA AID field 1380.
  • the number information field 1375 of the STA may include information on the number of STAs to receive the trigger frame 310 scheduled at the target transmission time
  • the STA AID field 1380 may include the trigger frame 1310 at the target transmission time.
  • the nominal minimum wake duration field 1335 may include information on the time at which the STA which has switched to the awake state for the reception of the trigger frame 1310 at the target transmission time maintains the awake state.
  • the STA that has switched to the awake state at the target transmission time may monitor the trigger frame 1310 while maintaining the awake state for the duration set by the nominal minimum wake duration field 1335 of the AP.
  • the STA receives the trigger frame 1310 during the set duration, and the UL frame 1315 including the uplink data buffered in response to the trigger frame 1310 through the UL MU PPDU (or on the UL MU PPDU). Can transmit
  • An acknowledgment (ACK) frame may be received from the AP, and may be switched to a doze state after a set duration. When the set duration ends, the STA may be switched to the doze state without transmitting the UL MU PPDU even when the trigger frame 1310 is received.
  • ACK acknowledgment
  • the STA may switch to the doze state after the set duration. Or, when the STA receives the trigger frame 1310 and there is no buffered uplink data during the set duration, the uplink frame 1315 in which the additional data bit is set to 0 or the power management (PM) bit is set to 1 to the AP. Can be transmitted.
  • the uplink frame 1315 in which the additional data bit is set to 0 or the power management (PM) bit is set to 1 to the AP. Can be transmitted.
  • the STA may be switched to the doze state even if the set time is not terminated.
  • ACK acknowledgment
  • the TWT wake interval field 1340 may include information on a transition interval to an awake state of an STA for receiving a trigger frame.
  • the STA may be switched to an awake state based on the information included in the target wake time field 1325 and the TWT wake interval field 1340 to receive the trigger frame 1310.
  • the TWT element disclosed in FIG. 13 does not include a request type field, but this is one example. That is, the request type field may be additionally included in the TWT element.
  • the request type field included in the TWT element may include a TWT flow indicator, and the TWT flow indicator may be included when a plurality of TWT related information is generated.
  • information on a target transmission time for transmitting a plurality of trigger frames may be transmitted using a length field.
  • the MAC frame 1400 includes a plurality of fields 1411 to 1419 constituting a MAC header, a frame body field 1420 including a payload and having a variable length, and error detection of a receiving terminal. It may include an FCS field 1430 for.
  • the frame control field 1411, the duration / ID field 1412, the first address field 1413, and the FCS field 1430 may be included in all types of MAC frames.
  • the field 1420 may be optionally included according to the type of the MAC frame.
  • the user field 1500 including the TWT info subfield 1530 of FIG. 15 corresponds to the HT control field 1419 of 4 octets (32 bytes) of FIG. 14. It can be understood as a field. That is, the user field 1500 according to the present embodiment may be understood as a field area included in the MAC header of the MAC frame.
  • the 2-bit reserved subfield 1510 of FIG. 15 may be set to '11', and the remaining subfields 1520 and 1530 may be allocated as an A-Control (Aggregated Control) field.
  • A-Control Aggregated Control
  • Information included in the subsequent subfield 1530 may be determined according to a value set in the control ID subfield 1520 of FIG. 15. Information included in the subsequent subfield 1530 associated with the value set in the control ID subfield 1520 may be defined as shown in Table 1 below.
  • the subsequent subfield 1530 uses 12 bits to change the operating mode of the user STA. It may indicate information for requesting the request. As another example, when the control ID subfield 1520 is set to '3', the subsequent subfield 1530 may indicate information for reporting the buffer status of the user STA using 26 bits.
  • the control ID subfield 1520 is set to '6'. Accordingly, the subsequent subfield 1530 may indicate TWT information for the power save operation. In the present specification, a subsequent subfield 1530 may be referred to as a TWT info subfield using 26 bits.
  • the TWT info subfield 1530 is a TWT Flow Identifier subfield 1531 using the first bit and the second bit B0-B1, and the third to tenth bits B2-B9.
  • the target wake time subfield 1532 using the first wakeup signal, the minimum wake duration subfield 1533 using the eleventh through eighteenth bits B10 through B17, and the nineteenth through 26th bits B18-B25 are used.
  • the TWT wake interval mantica subfield 1534 may be used.
  • the number of bits allocated to the TWT information subfield 1530 according to the present embodiment may be defined as a value different from the values exemplified in the present embodiment.
  • the TWT information subfield 1530 according to the present embodiment may be defined as a parameter of another name performing a similar function.
  • the flow identifier (TWT FID) subfield 1531 may be defined as shown in Table 2 below using the second bits B0-B1.
  • the AP may not transmit a trigger frame to which a resource unit for random access procedure is allocated in a broadcast TWT service interval.
  • the AP may transmit a trigger frame to which at least one resource unit for random access procedure is allocated in the broadcast TWT service interval.
  • the target wake time (TWT) subfield 1532 may inform the user STA receiving the MAC frame 1400 of FIG. 14 using the eighth bits B2-B9 when to transition from the doze state to the awake state. have.
  • the STA that receives the MAC frame 1400 of FIG. 14 may maintain the dose state until the time indicated by the target waketime subfield 1532.
  • the user STA may switch from the doze state to the awake state.
  • the minimum wake duration subfield 1533 may inform the user STA receiving the MAC frame 1400 of FIG. 14 using 8 bits B10-B17 to indicate a time interval in which an awake state is to be maintained.
  • the user STA switches to the awake state and then, in the minimum wake duration subfield 1533, to transmit uplink data using the trigger frame to be received from the AP.
  • the awake state can be maintained until the time indicated.
  • the user STA switches to the awake state and then until the time indicated by the minimum wake duration subfield 1533 for receiving downlink data received from the AP.
  • the state of wake can be maintained.
  • the TWT wake interval manticia subfield 1534 operates in a power save mode according to the doze state and the awake state to a user STA that receives the MAC frame 1400 of FIG. 14 using the eighth bit B18-B25. Can tell.
  • the user STA receiving the MAC frame 1400 of FIG. 14 performs an operation cycle of the power save mode according to the corresponding value. Can be set. That is, the user STA may periodically repeat the dose state and the awake state according to the TWT wake interval mantica subfield 1534.
  • MAC of a MAC frame (eg, 1400 of FIG. 14) including a user field 1500 transmitted and received between an AP and an STA in a roughly set broadcast TWT service interval (broadcast TWT SP)
  • broadcast TWT SP broadcast TWT service interval
  • a WLAN system having reduced power consumption by using a power save mode equipped with a more flexible TWT operation may be provided.
  • 16 and 17 illustrate an operation of a power saving mode using an M-STA BA frame according to another exemplary embodiment.
  • a block ACK ('M-STA BA') frame 1600 for multiple users includes a frame control field 1610, a duration field 1620, an RA field 1630, and a TA field 1640. , A BA control field 1650, a BA information field 1660, and an FCS field 1670.
  • the BA control field 1650 may be a common control field for the plurality of user STAs that have received the M-STA BA frame 1600.
  • the BA information field 1660 may have a variable length for each user STA that receives the M-STA BA frame 1600.
  • the BA information field 1660 may include one or more user-specific subfields individually assigned for a plurality of user STAs.
  • one or more user-specific subfields 1701 to 1765 and 1764 to 1765 may correspond to the BA information field 1660 of FIG. 16.
  • the M-STA BA frame according to the present embodiment may include first user-specific subfields 1771 to 1763 and second user-specific subfields 1764 and 1765 having different formats of subfields.
  • first user-specific subfields 1701 ⁇ 1763 of the M-STA BA frame may be understood as a field area for a first user STA (not shown).
  • the second user-specific subfields 1764 and 1765 may be understood as field fields for a second user STA (not shown).
  • the first user-specific subfields 1771-1763 include a Per-AID TID Info subfield of 17 octets, a Block Ack starting sequence control subfield of 2 octets and It may include a BA bitmap subfield 1763 of eight octets.
  • the first through eleventh bits BO-B10 of the Per-AID TID Info subfield 1701 may include identification information (eg, association identifier information) of the user STA.
  • identification information eg, association identifier information
  • all or part of the association identifier (AID) information of the first user STA that is the non-AP STA intended in the first user-specific subfields 1761 to 1763 may be included.
  • the ACK type information may be included in the twelfth bit B11 of the Per-AID TID Info subfield 1701.
  • the thirteenth through sixteenth bits B12-B15 of the Per-AID TID Info subfield 1701 may include traffic identifier (TID) information associated with Quality of Service (QoS) information.
  • TID traffic identifier
  • QoS Quality of Service
  • the second user-specific subfields 1764, 1765 of FIG. 17 may include a Per-AID TID Info subfield 1764 of 2 octets and an A-Control subfield 1765 of 8 octets. Can be.
  • the TWT information (corresponding to 1530 of FIG. 15) included in the A-Control subfield 1765 may need to be applied to all user STAs that have received the M-STA BA frame.
  • AID information for broadcast may be set in the first to eleventh bits BO-B10 of the Per-AID TID Info subfield 1764.
  • AID information for broadcast may be set to '0' or a preset value.
  • the TWT information (corresponding to 1530 of FIG. 15) included in the first through 26th bits B0-B25 of the A-Control subfield 1765 may include a plurality of user STAs that have received an M-STA BA frame. It can be applied to a specific user STA.
  • AID information for multicast or AID of a specific user STA may be set in the first through eleventh bits BO-B10 of the Per-AID TID Info subfield 1764.
  • a specific TID value may be set in the thirteenth through sixteenth bits B12-B15 of the Per-AID TID Info subfield 1764.
  • Whether the A-Control subfield 1765 includes TWT information is determined by the plurality of users who received the M-STA BA frame according to the value set in the Per-AID TID Info subfield 1764. It may be known to the STA.
  • TWT information included in the first through 26th bits B0-B25 of the A-Control subfield 1765 of FIG. 17 may be understood as information included in the TWT information subfield 1530 of FIG. 15.
  • the M-STA BA frame of FIG. 17 is described in more detail through section 9.3.1.9.7 of the standard document IEEE P802.11ax / D1.0, disclosed in November 2016.
  • FIG. 18 illustrates an operation of a power saving mode using an M-STA BA frame according to another embodiment.
  • the AP and the STA referred to herein are assumed to operate on a contention basis.
  • the AP may periodically transmit a beacon frame (hereinafter, referred to as 'BF').
  • the period of the beacon frame BF may be 100 ms (millisecond).
  • a time interval between periodically transmitted beacon frames may be referred to as a beacon interval.
  • the time intervals T1 to T10 between the first beacon frame BF1 and the second beacon frame BF2 of FIG. 18 may be referred to as beacon intervals.
  • the beacon frame of the present specification may include various elements as described in Section 9.3.3.3 of the standard document 802.11 REVmc / D8.0.
  • the beacon frame herein may include a TWT element disclosed in Section 9.4.200 of the standard document 802.11ax / D1.0.
  • the beacon frame of the present specification may be transmitted in a broadcast scheme.
  • the user STA of the present specification operates in a power save mode (hereinafter, referred to as a 'PS mode').
  • the user STA operating in the PS mode may be in an awake state or a doze state. That is, the user STA operating in the PS mode may transition from the awake state to the sleep state or transition from the sleep state to the awake state.
  • the STA in the awake state may transmit a frame to the AP or receive a frame transmitted from the AP.
  • the sleep STA user STA cannot transmit a frame to the AP and cannot receive a frame transmitted from the AP.
  • the user STA operating in the PS mode may switch from the awake state to the sleep state after receiving the beacon frame and maintain the sleep state at the beacon interval to reduce power consumption.
  • the user STA operating in the PS mode may maintain a sleep state until a subsequent beacon frame is received.
  • the user STA operating in the PS mode may switch to the awake state in a specific period of the beacon interval to receive data buffered in the AP or transmit data buffered to the user STA to the AP.
  • TWT target awake time
  • TWT non-service period in which the user STA sleeps.
  • the TWT service period (ie, including a TWT non-service period) mentioned in FIG. 18 may be commonly applied to a plurality of user STAs combined with an AP, which may be referred to as a broadcast TWT service period. Can be.
  • the horizontal axis of the AP 1800 denotes a time t of an AP perspective, and the vertical axis is related to the presence or absence of a frame transmitted by the AP 1800.
  • the horizontal axis of the first user STA 1810 refers to the time t1 from the perspective of the first user STA, and the vertical axis is associated with the presence or absence of a frame transmitted by the first user STA 1810.
  • the horizontal axis of the second user STA 1820 refers to the time t2 from the perspective of the second user STA, and the vertical axis is associated with the presence or absence of a frame transmitted by the second user STA 1820.
  • the AP 1800 and the first and second user STAs 1810 and 1820 may compete with each other to obtain a transmission opportunity (hereinafter, referred to as 'TXOP') for the channel. Can be done.
  • the AP 1800 of FIG. 12 and the first and second user STAs 1810 and 1820 may perform an enhanced distributed channel access (EDCA) based channel competition.
  • EDCA enhanced distributed channel access
  • the AP 1800 winning the channel competition may obtain a TXOP.
  • the AP 1800 may transmit the first beacon frame BF1.
  • the first beacon frame BF1 transmitted in the second period T1 to T2 may include a TWT element.
  • the first beacon frame BF1 of FIG. 18 may include a TWT parameter set for a TWT service interval (TWT SP).
  • TWT SP TWT service interval
  • the TWT parameter set may be a TWT service interval when start time information of the TWT service interval, duration information of the TWT service interval, and a plurality of TWT service intervals in the beacon interval exist. Interval information may be included.
  • TWT flow identifier TWT FID included in the first beacon frame BF1 is set to '2'.
  • the first and second user STAs 1810 and 1820 may receive the first beacon frame BF1 in an awake state.
  • the first and second user STAs 1810 and 1820 may operate based on a plurality of elements included in the received first beacon frame BF1.
  • the first and second user STAs 1810 and 1820 may transmit information about a start time of a broadcast TWT SP based on a TWT parameter set included in the first beacon frame BF1. Information about the duration of the broadcast TWT service interval and information about the cycle of the broadcast TWT service interval may be obtained.
  • the first and second user STAs 1810 and 1820 may be configured in the first and second broadcast TWT SPs based on a TWT flow identifier (TWT FID) included in the first beacon frame BF1.
  • TWT FID TWT flow identifier
  • the types of frames that the user STAs 1810 and 1820 may transmit to the AP, that is, information about an allowable group of the recommendation frame (for example, when the TWT FID is '2') may be obtained.
  • the AP 1800 of FIG. 18 may transmit a trigger frame including at least one resource unit for random access for a random access procedure.
  • the first and second user STAs 1810 and 1820 move from an awake state to a doze state after receiving the first beacon frame BF1. You can switch.
  • the first and second user STAs 1810 and 1820 may maintain a sleep state during the third periods T2 to T3.
  • the first and second user STAs 1810 and 1820 start time T3 of the broadcast TWT service section according to the TWT parameter set. It is possible to switch from the sleep state to the awake state at. In addition, the first and second user STAs 1810 and 1820 may maintain an awake state during the TWT service intervals (TWT SP, T3 to T4) according to the TWT parameter set.
  • the AP 1800 of FIG. 18 may transmit a trigger frame (hereinafter, 'random access trigger frame' or 'TF_R') for random access.
  • the random access trigger frame TF_R may be a frame in which the AID included in the user specific field (1110 of FIG. 11) for each user STA is assigned with '0'.
  • the first user STA 1810 may transmit a first uplink frame BSR1 to the AP 1800 by performing a random access procedure.
  • the first uplink frame BSR1 may be a buffer status report frame that informs the AP of information of traffic included in the QoS buffer of the first user STA 1810.
  • the second user STA 1820 may transmit a second uplink frame BSR2 to the AP 1800 by performing a random access procedure.
  • the second uplink frame BSR2 may be a buffer status report frame that informs the AP of information of traffic included in the QoS buffer of the second user STA.
  • the AP 1800 may block ACK (hereinafter, 'M-STA BA') for the plurality of user STAs to inform successful reception of the plurality of uplink frames BSR1 and BSR2 transmitted from the plurality of user STAs 1810 and 1820. ) Frame can be transmitted.
  • ACK hereinafter, 'M-STA BA'
  • the M-STA BA frame of FIG. 18 may be understood through the aforementioned contents of FIGS. 16 to 17.
  • the M-STA BA frame of FIG. 18 may include the first parameter information field TWT info1 for the first subsequent TWT service interval TWT SP1 of the first user STA 1810 and the second user STA 1820 of the second user STA 1820. 2 It may include a second parameter information field (TWT info2) for the subsequent TWT service interval (TWT SP2).
  • TWT info1 for the first subsequent TWT service interval
  • TWT SP2 second parameter information field for the subsequent TWT service interval
  • the first parameter information field TWT info1 may be a field area having the same format as the second user-specific subfields 1764 and 1765 of FIG. 17 for the first user STA 1810.
  • the first parameter information field TWT info1 may include a flow identifier (TWT FID) subfield (eg, 1531 of FIG. 15), a target wake time subfield (eg, 1532 of FIG. 15), and a minimum value.
  • TWT FID flow identifier
  • 15 may include a wake duration subfield (eg, 1533 of FIG. 15) and a TWT wake interval mantica subfield (eg, 1534 of FIG. 15).
  • the flow identifier (TWT FID) subfield of the first parameter information field (TWT info1) may indicate a restriction on the type of frames transmitted by the AP and the user STA in the first subsequent TWT service interval (TWT SP1).
  • the target wake time subfield of the first parameter information field (TWT info1) is awake again for the first subsequent TWT service interval (TWT SP1) after the end of this broadcast TWT service interval (TWT SP1).
  • a time point for switching to the state may be indicated to the user STA receiving the M-STA BA frame.
  • the TWT wake interval manticia subfield of the first parameter information field TWT info1 may indicate a period of a power save operation for the first subsequent TWT service interval (TWT SP1) to the user STA receiving the M-STA BA frame. have.
  • the power save operation performed by the user STA may be implemented by switching the doze state and the awake state.
  • the second parameter information field TWT info2 may be a field area having the same format as the second user-specific subfields 1764 and 1765 of FIG. 17 for the second user STA 1820.
  • the second parameter information field TWT info2 may include a flow identifier (TWT FID) subfield (eg, 1531 of FIG. 15), a target wake time subfield (eg, 1532 of FIG. 15), A minimum wake duration subfield (eg, 1533 of FIG. 15) and a TWT wake interval mantica subfield (eg, 1534 of FIG. 15) may be included.
  • TWT FID flow identifier
  • target wake time subfield eg, 1532 of FIG. 15
  • a minimum wake duration subfield eg, 1533 of FIG. 15
  • TWT wake interval mantica subfield eg, 1534 of FIG. 15
  • the flow identifier (TWT FID) subfield of the second parameter information field (TWT info2) may indicate a restriction on the type of frames transmitted by the AP and the user STA in the second subsequent TWT service interval (TWT SP2).
  • the target wake time subfield of the second parameter information field (TWT info2) is awake again for the second subsequent TWT service interval (TWT SP2) after the end of this broadcast TWT service interval.
  • TWT info2 The target wake time subfield of the second parameter information field (TWT info2) is awake again for the second subsequent TWT service interval (TWT SP2) after the end of this broadcast TWT service interval.
  • TWT SP2 the second subsequent TWT service interval
  • a time point for switching to the state may be indicated to the user STA receiving the M-STA BA frame.
  • the TWT wake interval manticia subfield of the second parameter information field TWT info2 may indicate a period of a power save operation for a second subsequent TWT service interval (TWT SP2) to the STA that receives the M-STA BA frame.
  • TWT SP2 second subsequent TWT service interval
  • the power save operation performed by the user STA may be implemented by switching the doze state and the awake state.
  • the first and second user STAs 1810 and 1820 according to the present embodiment, the end point T4 of the broadcast TWT service section according to the TWT parameter set, T4. It is possible to switch from the awake state to the sleep state at.
  • the first and second user STAs 1810 and 1820 may maintain a sleeping state in the fifth section T4 to T5.
  • the first user STA 1810 may wake the frame in the first subsequent TWT service section TWT SP1 according to the first parameter information field TWT info1. State can be maintained.
  • the first user STA 1810 may successfully transmit the first uplink data frame UL D1 in response to the first trigger frame TF1 transmitted from the AP.
  • the first trigger frame TF1 may be understood as a basic trigger frame including identifier information indicating the first user STA and resource units individually allocated for the first user STA.
  • the second user STA 1820 may maintain a sleep state according to the second parameter information field TWT info2.
  • the first user STA 1810 may move from the awake state at the end time T6 of the first subsequent TWT service period TWT SP1 according to the first parameter information field TWT info1. You can switch to sleep.
  • the first user STA 1810 may maintain a sleep state in the seventh periods T6 to T7.
  • the second user STA 1820 may maintain a sleep state according to the second parameter information field TWT info2.
  • the first user STA 1810 may maintain a sleep state according to the first parameter information field TWT info1.
  • the second user STA 1820 may successfully transmit the second uplink data frame UL D2 in response to the second trigger frame TF2 transmitted from the AP.
  • the second trigger frame TF2 may be understood as a basic trigger frame including identifier information indicating the second user STA and resource units individually allocated for the second user STA.
  • the first user STA 1810 may maintain a sleep state according to the first parameter information field TWT info1.
  • the second user STA 1820 may switch from the awake state to the sleep state at the end time T8 of the second subsequent TWT service interval TWT SP2 according to the second parameter information field TWT info2.
  • the second user STA 1820 may maintain a sleep state in the ninth periods T8 to T9.
  • the AP 1800 and the first and second user STAs 1810 and 1820 may again perform channel competition for obtaining a transmission opportunity (TXOP) for the channel.
  • TXOP transmission opportunity
  • the M-STA TWT information for each STA may be signaled through a BA frame.
  • a WLAN system having a more flexible TWT operation than that of the related art may be provided.
  • FIG. 19 is a flowchart illustrating a method for power management in a WLAN system according to an exemplary embodiment.
  • the TWT service frame referred to in FIG. 19 may be understood to include the user field 1500 mentioned in FIG. 15.
  • the user STA mentioned in FIG. 19 may be understood as an STA operating in a power save mode.
  • the user STA may receive a beacon frame including TWT parameter information for a preset broadcast target awake time service period from an access point (AP). For example, the user STA receiving the beacon frame may switch to the doze state.
  • AP access point
  • the broadcast TWT service period may be a period in which a plurality of user STAs combined with the AP maintains an awake state for a specific time from a specific time point determined according to the TWT parameter information.
  • the user STA may switch from a doze state to an awake state in the broadcast TWT service interval based on the TWT parameter information.
  • the broadcast TWT service period may be a period in which a plurality of user STAs combined with the AP maintain an awake state for a specific time from a specific time point determined according to the TWT parameter information.
  • the user STA may receive a TWT service frame from the AP including subsequent TWT parameter information for a subsequent TWT service interval that is individually configured for the user STA in the broadcast TWT service interval.
  • subsequent TWT parameter information may be understood as information included in the user field 1500 mentioned in FIG. 15. That is, subsequent TWT parameter information may be understood as information included in a medium access control header (MAC) header of the TWT service frame.
  • MAC medium access control header
  • the user STA may switch from a doze state to an awake state in a subsequent TWT service interval based on the subsequent TWT parameter information.
  • the user STA may communicate with the AP in a subsequent TWT service interval.
  • the user STA may receive a trigger frame from the AP that individually allocates uplink radio resources for a plurality of users in a subsequent TWT service period. Subsequently, the user STA may transmit a trigger-based frame to the AP using a radio resource in response to the trigger frame.
  • the user STA may receive a downlink frame from the AP in a subsequent TWT service period.
  • the subsequent TWT parameter information is transmitted in a first field indicating when the user STA is to be switched from an awake state to a doze state for a subsequent TWT service interval, a second field indicating a duration of the subsequent TWT service interval, and a subsequent TWT service interval. And a third field indicating this allowed recommendation frame and a fourth field indicating a period of a subsequent TWT service interval.
  • 20 is a block diagram illustrating a wireless terminal to which an embodiment can be applied.
  • a wireless terminal may be an STA or an AP or a non-AP STA, which 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 2000 includes a processor 2010, a memory 2020, and an RF unit 2030.
  • the RF unit 2030 may be connected to the processor 2010 to transmit / receive a radio signal.
  • the processor 2010 may implement the functions, procedures, and / or methods proposed herein. For example, the processor 2010 may perform an operation according to the present embodiment described above. The processor 2010 may perform an operation of the AP disclosed in the present embodiment of FIGS. 1 to 19.
  • the non-AP STA 2050 includes a processor 2060, a memory 2070, and an RF unit 2080.
  • the RF unit 2080 may be connected to the processor 2060 to transmit / receive a radio signal.
  • the processor 2060 may implement the functions, processes, and / or methods proposed in the present embodiment.
  • the processor 2060 may be implemented to perform the non-AP STA operation according to the present embodiment described above.
  • the processor 2060 may perform an operation of the non-AP STA disclosed in the present embodiment of FIGS. 1 to 19.
  • the processors 2010 and 2060 may include an application-specific integrated circuit (ASIC), another chip set, a logic circuit, a data processing device, and / or a converter for converting baseband signals and radio signals to each other.
  • the memories 2020 and 2070 may include read-only memory (ROM), random access memory (RAM), flash memory, memory cards, storage media and / or other storage devices.
  • the RF unit 2030 and 2080 may include one or more antennas for transmitting and / or receiving a radio signal.
  • Modules may be stored in memories 2020 and 2070 and executed by processors 2010 and 2060.
  • the memories 2020 and 2070 may be inside or outside the processors 2010 and 2060, and may be connected to the processors 2010 and 2060 by various well-known means.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

La présente invention concerne un procédé de gestion de puissance dans un système de réseau local (LAN) sans fil qui consiste : à recevoir, par une station (STA) d'utilisateur et d'un point d'accès (AP), une trame de balise comprenant des informations de paramètre TWT pendant un intervalle de service TWT de diffusion pré-établi; à commuter d'un état de veille à un état activé dans l'intervalle de service TWT de diffusion sur la base d'informations de paramètre TWT; à recevoir, de l'AP, une trame de service TWT comprenant des informations de paramètre TWT ultérieur pour un intervalle de service TWT ultérieur qui est établi individuellement pour la STA d'utilisateur dans l'intervalle de service TWT de diffusion, les informations de paramètre TWT ultérieur étant des informations incluses dans un en-tête de contrôle d'accès au support (MAC) de la trame de service TWT; à commuter de l'état activé à l'état de veille après l'intervalle de service TWT de diffusion; à commuter de l'état de veille à l'état activé et à établir une communication avec l'AP dans l'intervalle de service TWT ultérieur sur la base d'informations de paramètre TWT ultérieur.
PCT/KR2017/003186 2016-03-25 2017-03-24 Procédé de gestion de puissance dans un système lan sans fil et terminal sans fil l'utilisant WO2017164687A1 (fr)

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CN111771398B (zh) * 2018-02-27 2023-10-24 高通股份有限公司 Twt会话和成员资格的暂停、恢复和拆除
CN111771398A (zh) * 2018-02-27 2020-10-13 高通股份有限公司 Twt会话和成员资格的暂停、恢复和拆除
CN111989954A (zh) * 2018-03-02 2020-11-24 交互数字专利控股公司 用于信道接入和恢复唤醒无线电的方法和装置
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WO2019190221A1 (fr) * 2018-03-28 2019-10-03 엘지전자 주식회사 Procédé et dispositif d'émission d'un paquet de réveil dans un système de lan sans fil
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WO2022060049A1 (fr) * 2020-09-15 2022-03-24 엘지전자 주식회사 Procédé et dispositif permettant d'effectuer une détection dans un mode d'économie d'énergie dans un système lan sans fil
WO2022092525A1 (fr) * 2020-10-30 2022-05-05 삼성전자 주식회사 Dispositif électronique permettant d'ordonnancer à nouveau un canal sans fil sur la base d'un environnement de canal sans fil, et procédé de commande associé
US11943639B2 (en) 2020-10-30 2024-03-26 Samsung Electronics Co., Ltd. Electronic device performing rescheduling over wireless channel and method for controlling same
US20220201533A1 (en) * 2020-12-18 2022-06-23 Samsung Electronics Co., Ltd. Adaptive adjustment for target wake time duration configuration
US11910225B2 (en) * 2020-12-18 2024-02-20 Samsung Electronics Co., Ltd. Adaptive adjustment for target wake time duration configuration
WO2022158801A1 (fr) * 2021-01-19 2022-07-28 엘지전자 주식회사 Procédé et dispositif de signalisation d'ersp dans un système lan sans fil
WO2022257147A1 (fr) * 2021-06-11 2022-12-15 Guangdong Oppo Mobile Telecommunications Corp., Ltd. Point d'accès, station et procédé de communication sans fil

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