WO2019050294A1 - Method for performing operation in accordance with power save mode in wireless lan system and wireless terminal using same - Google Patents

Abstract

A method for performing an operation in accordance with a PS mode in a wireless LAN system comprises the steps of: performing a receiving operation for an EDMG MU PPDU, wherein the EDMG MU PPDU includes a preamble and a plurality of A-MPDUs having the same length transmitted on an overlapped time resource, the preamble includes first order information on a transmission order of a first block ACK frame for a first A-MPDU to be transmitted to a first STA among the plurality of A-MPDUs, and the transmission order is determined according to a length of a data area included in the first A-MPDU; converting a power state of the first STA into a doze state at a first time when the reception of the first data area included in the first A-MPDU is finished, if it is determined that the transmission order of the first block ACK frame is not the first on the basis of the first order information; maintaining, as the doze state, the power state from the first time to a second time; and converting the power state into an awake state after the second time elapses.

Description

A method of performing an operation according to a power saving mode in a wireless LAN system and a method

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to wireless communication, and more particularly, to a method of performing an operation according to a power save mode in a wireless LAN system and a wireless terminal using the same.

The Institute of Electrical and Electronics Engineers (IEEE) 802.11ad standard is a high-speed wireless communication standard operating in a band of 60 GHz or higher. The reach of the signal is about 10 meters, but the throughput can support more than 6Gbps. Because it operates in the higher frequency bands, signal propagation is dominated by ray-like propagation. The better the signal quality is, the better the alignment of the TX (transmit) or RX (receive) antenna beam towards a strong spatial signal path.

The IEEE 802.11ad standard provides a beamforming training process for antenna beam alignment. IEEE 802.11ay is a next-generation standard that is being developed based on IEEE 802.11ad with a goal of over 20 Gbps throughput.

It is an object of the present invention to provide a method for performing an operation according to a power saving mode in a wireless local area network (WLAN) system and a wireless terminal using the same in order to support improved performance in terms of power consumption of a wireless terminal.

A method for performing an operation according to a PS mode in a wireless LAN system according to an exemplary embodiment of the present invention is characterized in that a first STA performs a reception operation for an EDMG MU PPDU, the EDMG MU PPDU is received from an AP, Wherein the MU PPDU includes a plurality of A-MPDUs having the same length transmitted on a preamble and an overlapped time resource, each of the plurality of A-MPDUs includes a data area of a different length for each of a plurality of receivers, MPDU of the first A-MPDU to be transmitted to the first STA, and a transmission order of the first block ACK frame for the first A-MPDU to be transmitted to the first STA among the A- The length being determined according to the length; The first STA determining whether the transmission order of the first block ACK frame is first based on the first order information; When it is determined that the transmission order is not the first, the first STA switches the power state of the first STA to the doze state at the first time point at which the reception of the first data area included in the first A-MPDU is completed ; Wherein the first STA maintains the power state in a dosed state from a first time point to a second time point, the second time point being obtained based on the first order information; And when the second time lapses, the first STA switches the power state from the doze state to the awake state.

According to an embodiment of the present invention, there is provided a method of performing an operation according to a power saving mode in a wireless local area network (WLAN) system and a wireless terminal using the method, in order to support improved performance in terms of power consumption of a wireless terminal.

1 is a conceptual diagram showing a structure of a wireless LAN system.

2 is a conceptual diagram of a layered architecture of a wireless LAN system supported by IEEE 802.11.

3 is a conceptual diagram of an STA supporting EDCA in a wireless LAN system.

4 is a conceptual diagram illustrating a backoff procedure according to EDCA.

5 is a diagram for explaining a frame transmission procedure in a wireless LAN system.

6 is a conceptual diagram of a wireless terminal for transmitting a frame in the wireless LAN system according to the present embodiment.

FIG. 7 is a diagram illustrating a plurality of channels channelized for frame transmission in the wireless LAN system according to the present embodiment.

8 is a diagram illustrating a format of an EDMG PPDU according to an embodiment of the present invention.

FIG. 9 shows the format of an EDMG group ID set element according to the present embodiment.

FIG. 10 shows the format of the EDMG group field included in the EDMG group ID set element according to the present embodiment.

11 and 12 show the format of the EDMG group field included in the EDMG group ID set element according to the present embodiment.

13 is a conceptual diagram showing a configuration of an EDMG group according to the present embodiment and a wireless LAN system after performing an MU-MIMO beamforming protocol.

FIG. 14 is a diagram illustrating a method of performing an operation according to a power save mode in a wireless LAN system according to the present embodiment.

15 is a flowchart illustrating a method of performing an operation according to a power save mode in a wireless LAN system according to the present embodiment.

16 is a block diagram showing a wireless device to which this embodiment can be applied.

17 is a block diagram showing an example of a device included in the processor.

The foregoing features and the following detailed description are exemplary only in order to facilitate explanation and understanding of the specification. That is, the present disclosure is not limited to these embodiments, but may be embodied in other forms. The following embodiments are merely illustrative of the complete disclosure of the present disclosure and are intended to be illustrative of the present disclosure to those of ordinary skill in the art to which this disclosure belongs. Thus, where there are several ways to implement the components of the present disclosure, it is necessary to make it clear that the implementation of the present specification is possible in any of these methods, or any equivalent thereof.

It is to be understood that, in the context of this specification, when reference is made to a configuration including certain elements, or when it is mentioned that a process includes certain steps, other elements or other steps may be included. In other words, the terms used herein are for the purpose of describing particular embodiments only, and are not intended to limit the concepts of the present specification. Further, the illustrative examples set forth to facilitate understanding of the invention include its complementary embodiments.

The terms used herein have the meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. Commonly used terms should be construed in a manner consistent with the context of this specification. Also, terms used in the specification should not be construed as being excessively ideal or formal in nature unless the meaning is clearly defined. BRIEF DESCRIPTION OF THE DRAWINGS Fig.

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

Referring to FIG. 1A, the WLAN system 10 of FIG. 1A includes at least one Basic Service Set (hereinafter referred to as 'BSS', 100, and 105). A BSS is a set of access points (APs) and stations (hereinafter, referred to as 'STAs') that can successfully communicate with each other and communicate with each other.

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

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

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

The portal 150 may serve as a bridge for performing a connection between a wireless LAN network (IEEE 802.11) and another network (for example, 802.X).

A network between the APs 110 and 130 and a network between the APs 110 and 130 and the STAs 100-1, 105-1 and 105-2 in the wireless LAN having the structure shown in FIG. 1 (A) .

1 (B) is a conceptual diagram showing an independent BSS. 1 (B), the wireless LAN system 15 of FIG. 1 (B) is different from FIG. 1 (A) in that a network is set up between STAs without APs 110 and 130 to perform communication . An ad-hoc network or an independent basic service set (IBSS) is defined as a network that establishes a network and establishes communication between STAs without APs 110 and 130.

Referring to FIG. 1 (B), the IBSS 15 is a BSS operating in an ad-hoc mode. Since IBSS does not include APs, there is no centralized management entity. Therefore, 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 connection to a distributed system is not allowed. All STAs in an IBSS form a self-contained network.

The STA referred to herein includes a Medium Access Control (MAC) layer and a Physical Layer interface to a wireless medium in accordance with the IEEE 802.11 standard. As a functional medium, the optical path may be used to include both an AP and a non-AP STA (Non-AP Station).

The STA referred to herein may be a mobile terminal, a wireless device, a wireless transmit / receive unit (WTRU), a user equipment (UE), a mobile station (MS) , A mobile subscriber unit, or simply a user.

2 is a conceptual diagram of a layered architecture of a wireless LAN system supported by IEEE 802.11. 2, the hierarchical architecture of the WLAN system includes a physical medium dependency (PMD) sublayer 200, a physical layer convergence procedure (PLCP) sublayer 210 and a medium access control (MAC) sublayer 220. The media access control (MAC)

The PMD sublayer 200 may serve as a transmission interface for transmitting and receiving data between a plurality of STAs. The PLCP sub-layer 210 is implemented such that the MAC sub-layer 220 can operate with minimal dependency on the PMD sub-layer 200.

The PMD sublayer 200, the PLCP sublayer 210 and the MAC sublayer 220 may conceptually include a management entity, respectively. For example, the management unit of the MAC sublayer 220 is referred to as a MAC Layer Management Entity (MLME) 225. The management unit of the physical layer is referred to as a PHY Layer Management Entity (PLME) 215.

These management units may provide an interface for performing layer management operations. For example, the PLME 215 may be connected to the MLME 225 to perform a management operation of the PLCP sub-layer 210 and the PMD sub-layer 200. The MLME 225 may be coupled to the PLME 215 to perform a management operation of the MAC sublayer 220.

In order for the correct MAC layer operation to be performed, an STA management entity (hereinafter, 'SME', 250) may exist. The SME 250 may be operated as a component independent of each layer. The PLME 215, the MLME 225, and the SME 250 may transmit and receive information to each other based on a primitive.

The operation of each sub-layer will be briefly described below. For example, the PLCP sublayer 210 may transmit a MAC Protocol Data Unit (MAC PDU) received from the MAC sublayer 220 according to an instruction of the MAC layer between the MAC sublayer 220 and the PMD sublayer 200, MPDU ') to the PMD sublayer 200 or a frame from the PMD sublayer 200 to the MAC sublayer 220.

The PMD sublayer 200 can perform data transmission and reception between a plurality of STAs via a wireless medium as a PLCP lower layer. The MPDU transmitted from the MAC sublayer 220 is referred to as a physical service data unit (PSDU) in the PLCP sublayer 210. MPDUs are similar to PSDUs, but when an aggregated MPDU (aggregated MPDU) aggregating multiple MPDUs is delivered, the individual MPDUs and PSDUs may be different.

The PLCP sublayer 210 adds an additional field including necessary information by the transceiver of the physical layer in the process of receiving the PSDU from the MAC sublayer 220 and transmitting the PSDU to the PMD sublayer 200. A field added at this time may be a PLCP preamble, a PLCP header, a tail bit for returning the convolutional encoder to a zero state, and the like in the PSDU

In the PLCP sublayer 210, the above-described field is added to the PSDU to generate a PLCP Protocol Data Unit (PPDU) and transmitted to the receiving station via the PMD sublayer 200. The receiving station receives the PPDU and transmits the PLCP preamble and the PLCP And obtains information necessary for restoring data from the header.

3 is a conceptual diagram of an STA supporting EDCA in a wireless LAN system.

An STA (or an AP) that performs channel access based on enhanced distributed channel access (EDCA) in a wireless LAN system can perform channel access according to a plurality of predefined user priorities for traffic data .

For transmission of Quality of Service (QoS) data frames based on a plurality of user priorities, the EDCA includes four access categories (AC) (AC_BK (background), AC_BE (best effort) , AC_VO (voice)).

The STA that performs channel access based on the EDCA transmits traffic data such as MAC service data unit (MSDU) arriving from a logical link control (LLC) layer to a MAC (Medium Access Control) layer as shown in Table 1 below Can be mapped. Table 1 is an exemplary table showing the mapping between user priorities and AC.

For each AC, a transmission queue and an AC parameter can be defined. A plurality of user priorities may be implemented based on AC parameter values set differently for each AC.

The STA performing the channel access based on the EDCA performs DCF interframe space (DIFS), CWmin, and CWmax (DCF) parameters based on a distributed coordination function (DCF) when performing a backoff procedure for transmitting frames belonging to each AC. Instead, an arbitration interframe space (AIFS) [AC], a CWmin [AC], and a CWmax [AC] can be used, respectively.

For reference, the default values of the parameters corresponding to each AC are shown in Table 2 below as an example.

The EDCA parameters used in the AC-specific backoff procedure can be set to default values or carried in the beacon frame from the AP to each STA. The lower the values of AIFS [AC] and CWmin [AC] are, the higher the priority is, and accordingly, the channel access delay is shortened so that more bandwidth can be used in a given traffic environment.

The EDCA parameter set element may contain information for each AC-specific channel access parameter (e.g., AIFS [AC], CWmin [AC], CWmax [AC]).

If a collision occurs between STAs while the STA is transmitting a frame, the backoff procedure of the EDCA that generates a new backoff count is similar to the backoff procedure of the existing DCF.

The differentiated backoff procedure for each AC of the EDCA can be performed based on the EDCA parameters individually set for each AC. The EDCA parameters can be an important means for differentiating channel access of various user priority traffic.

Properly setting the EDCA parameter values defined for each AC can optimize the network performance and increase the transmission effect by priority of the traffic. Thus, the AP can perform overall management and coordination functions on the EDCA parameters to ensure fair access to all STAs participating in the network.

In this specification, a user priority predefined (or pre-assigned) for traffic data (or traffic) may be referred to as a traffic identifier (TID).

The transmission priority of the traffic data can be determined based on the user priority. Referring to Table 1, the traffic identifier (TID) of the traffic data having the highest user priority can be set to '7'. That is, traffic data whose traffic identifier (TID) is set to '7' can be understood as traffic having the highest transmission priority.

Referring to FIG. 3, one STA (or AP 300) may include a virtual mapper 310, a plurality of transmission queues 320 to 350, and a virtual collision processor 360.

The virtual mapper 310 of FIG. 3 may map the MSDU received from the LLC (logical link control) layer to a transmission queue corresponding to each AC according to Table 1 above.

The plurality of transmission queues 320 to 350 of FIG. 3 may serve as separate EDCA contention entities for channel access to the wireless medium within one STA (or AP).

For example, the transmission queue 320 of the AC VO type of FIG. 3 may include one frame 321 for a second STA (not shown). The AC VI type transmission queue 330 includes three frames 331 to 333 for a first STA (not shown) and one frame 334 (for a third STA) ).

The AC BE type transmission queue 340 of FIG. 3 includes one frame 341 for a second STA (not shown), one frame 341 for a third STA (not shown) in order to be transmitted to the physical layer 342 for one STA and one frame 343 for a second STA (not shown). Illustratively, the transmit queue 350 of the AC BE type may not include a frame to be transmitted to the physical layer.

For example, an internal backoff value for an AC VO type transmission queue 320, an AC VI type transmission queue 330, an AC BE type transmission queue 340, and an AC BK type transmission queue 350 Can be computed separately based on Equation (1) and the set of channel access parameters for each AC (i.e., AIFS [AC], CWmin [AC], CWmax [AC] in Table 2).

STA 400 may perform an internal backoff procedure based on an internal backoff value for each transmission queue 320, 330, 340, In this case, the transmission queue that first completes the internal backoff procedure may be understood as a transmission queue corresponding to the primary AC.

A frame included in a transmission queue corresponding to a primary AC may be transmitted to another entity (e.g., another STA or AP) during a TXOP (transmission opportunity). If there are more than two ACs that have been backed off at the same time, the collision between the ACs can be adjusted according to the function (EDCA function, EDCAF) included in the virtual collision handler 360.

That is, when an AC collision occurs, a frame included in AC having a higher priority can be transmitted first. Other ACs may also increase the contention window value and update the value set in the backoff count.

When one frame buffered in the transmission queue of the primary AC is transmitted, the STA can determine whether the next frame in the same AC is transmitted for the remaining TXOP time and can receive ACK therefrom. In this case, the STA attempts to transmit the next frame after the SIFS time interval.

The TXOP limit value may be set to a default value for the AP and the STA, or a frame associated with the TXOP limit value from the AP may be delivered to the STA. If the size of the data frame to be transmitted exceeds the TXOP limit value, the STA may fragment the frame into several small frames. Subsequently, the segmented frame may be transmitted within a range that does not exceed the TXOP limit value.

4 is a conceptual diagram illustrating a backoff procedure according to EDCA.

Each STA may share a wireless medium based on a contention-based distributed coordination function (DCF). DCF is an access protocol for coordinating collisions between STAs and can use carrier sense multiple access / collision avoidance (CSMA / CA).

If it is determined by the DCF that the wireless medium is not used during the DIFS (DCF inter frame space) (i.e., the wireless medium is in the idle state), the STA can acquire transmission authority to transmit internally determined MPDU over the wireless medium . For example, an internally determined MPDU can be understood as a frame included in the transmission queue of the primary AC mentioned in FIG.

If it is determined by the DCF that the wireless medium is to be used by another STA (i.e., the wireless medium is busy) in the DIFS, the STA may determine that the wireless medium is to be used by the STA in order to obtain transmission authority to transmit the internally determined MPDU over the wireless medium. it can wait until it becomes an idle state.

The STA may then defer channel access as much as DIFS based on when the wireless medium is switched to the idle state. Then, the STA can wait for a contention window (CW) set in the backoff counter.

To perform the backoff procedure according to the EDCA, each STA may set a backoff value arbitrarily selected in the contention window (CW) to the backoff counter. For example, to perform the backoff procedure according to the EDCA, the backoff value set in the backoff counter of each STA may be determined by the internal backoff value used in the internal backoff procedure to determine the primary AC of each STA .

In addition, the backoff value set in the backoff counter of each STA is calculated by the following equation (1) and the channel access parameter set for each AC (i.e., AIFS [AC] in Table 2, CWmin [AC], and CWmax [AC]) of the STA.

In this specification, the time in which the backoff value selected by each STA is expressed in slot time units can be understood as the backoff window of FIG.

Each STA can perform a countdown operation of decreasing the backoff window set in the backoff counter by the slot time unit. The STA having the relatively shortest backoff window among a plurality of STAs can acquire a transmission opportunity (hereinafter, referred to as 'TXOP') which is an authority to occupy the wireless medium.

During the time interval for the transmission opportunity (TXOP), the remaining STAs may stop the countdown operation. The remaining STAs may wait until the time interval for the transmission opportunity (TXOP) has expired. After the time interval for the transmission opportunity (TXOP) expires, the remaining STAs may resume the paused countdown operation to occupy the wireless medium.

According to the DCF-based transmission method, collision between STAs that may occur when a plurality of STAs simultaneously transmit frames can be prevented. However, the channel access scheme using DCF has no concept of transmission priority (i.e., user priority). That is, when the DCF is used, the quality of service (QoS) of the traffic to be transmitted by the STA can not be guaranteed.

In order to solve this problem, a new coordination function, a hybrid coordination function (HCF) is defined in 802.11e. The newly defined HCF has better performance than the channel access performance of the existing DCF. HCF can utilize two channel access schemes, HCF controlled channel access (HCCA) and enhanced distributed channel access (EDCA), for QoS enhancement purposes.

Referring to FIG. 4, it can be assumed that the STA attempts to transmit buffered traffic data. The user priorities set for each traffic data can be differentiated as shown in Table 1. < tb > < TABLE > The STA may include an output queue of four types (AC_BK, AC_BE, AC_VI, AC_VO) mapped to the user priority of Table 1.

STA can transmit traffic data based on AIFS (Arbitration Interframe Space) instead of DIFS (DCF Interframe Space) used in the past.

Hereinafter, in an embodiment of the present invention, a wireless terminal (i.e., STA) may be a device capable of supporting both a wireless LAN system and a cellular system. That is, the wireless terminal can be interpreted as a UE supporting a cellular system or an STA supporting a wireless LAN system.

Inter-Frame Spacing referred to in 802.11 is described for the sake of brevity. For example, the interframe interval (IFS) may include a reduced interframe space (RIFS), a short interframe space (SIFS), a PCF interframe space (PIFS) : DCF interframe space, arbitration interframe space (AIFS), or extended interframe space (EIFS).

The inter-frame interval (IFS) can be determined according to the attributes specified by the physical layer of the STA regardless of the bit rate of the STA. The rest of the interframe interval (IFS) except for AIFS can be understood as a fixed value for each physical layer.

The AIFS can be set to a value corresponding to the user priority and the four types of transmission queues mapped as shown in Table 2 above.

SIFS has the shortest time gap among the above-mentioned IFSs. Accordingly, the STA occupying the wireless medium can be used when it is necessary to maintain occupancy of the medium without disturbance by another STA in a period in which a frame exchange sequence is performed.

That is, by using the smallest gap between transmissions in the frame exchange sequence, priority can be given to completion of the ongoing frame exchange sequence. In addition, an STA accessing a wireless medium using SIFS may initiate transmission directly at the SIFS boundary without determining whether the medium is Busy.

The duration of SIFS for a particular physical (PHY) layer can be defined by the aSIFSTime parameter. For example, the SIFS value in the physical layer (PHY) of IEEE 802.11a, IEEE 802.11g, IEEE 802.11n, and IEEE 802.11ac standards is 16 μs.

PIFS may be used to provide the STA with a higher priority next to the SIFS. That is, the PIFS may be used to obtain priority for accessing the wireless medium.

DIFS can be used by the STA to transmit data frames (MPDUs) and management protocol (Mac Protocol Data Units (MPDUs)) based on the DCF. After the received frame and the backoff time have expired, if the medium is determined to be idle via a carrier sense mechanism (CS), the STA may transmit the frame.

5 is a diagram for explaining a frame transmission procedure in a wireless LAN system.

4 and 5, each of the STAs 510, 520, 530, 540 and 550 of the WLAN system transmits a backoff value for performing the backoff procedure according to EDCA to each STA 510, 520, 530, 540 and 550, respectively.

Each STA 510, 520, 530, 540, 550 may attempt to transmit after waiting for a set backoff value for a time in slot time units (i.e., the backoff window of FIG. 4).

In addition, each STA 510, 520, 530, 540, and 550 may reduce the backoff window in units of slot time through a countdown operation. The countdown operation for channel access to the wireless medium may be performed separately by each STA.

Each STA can individually set a backoff time (Tb [i]) corresponding to the backoff window to the backoff counter of each STA. Specifically, the backoff time Tb [i] is a pseudo-random integer value and can be calculated based on the following equation (1).

Random (i) in Equation (1) is a function that uses a uniform distribution and generates an arbitrary integer between 0 and CW [i]. CW [i] can be understood as a contention window selected between the minimum contention window CWmin [i] and the maximum contention window CWmax [i].

For example, the minimum contention window CWmin [i] and the maximum contention window CWmax [i] may correspond to the default values CWmin [AC] and CWmax [AC] in Table 2, respectively.

For initial channel access, the STA can select any integer between O and CWmin [i] using Random (i) with CW [i] set to CWmin [i]. In this case, any selected integer may be referred to as a backoff value.

I in Equation (1) can be understood to correspond to the user priority in Table 1. That is, it can be understood that the traffic buffered in the STA corresponds to any one of AC_VO, AC_VI, AC_BE, or AC_BK in Table 1 based on the value set in i of Equation (1).

The SlotTime of Equation (1) can be used to provide enough time for the preamble of the transmitting STA to be detected by the neighboring STA. The slot time (SlotTime) in Equation (1) can be used to define the above-mentioned PIFS and DIFS. For example. The slot time (SlotTime) may be 9 [micro] s.

For example, if the user priority (i) is '7', the initial backoff time Tb [7] for a transmission queue of AC_VO type is set to a value between 0 and CWmin [AC_VO] And may be expressed in units of time (SlotTime).

The STA calculates an increased backoff time Tb [i] 'based on the following equation (2): " (2) " Can be newly calculated.

Referring to Equation (2), a new contention window CW _new [i] can be computed based on the previous window CW _old [i]. The PF value of Equation (2) can be calculated according to the procedure defined in the IEEE 802.11e standard. For example, the PF value of Equation 2 may be set to '2'.

In this embodiment, the increased backoff time Tb [i] ') is set to a slot time at a certain integer (i.e., a backoff value) selected between 0 and the new contention window CW _new [i] It can be understood as a time expressed in units.

The CWmin [i], CWmax [i], AIFS [i] and PF values mentioned in FIG. 5 may be signaled from the AP through a QoS parameter set element which is a management frame. The CWmin [i], CWmax [i], AIFS [i], and PF values may be preset values by the AP and the STA.

Referring to FIG. 5, the horizontal axes t1 to t5 for the first to fifth STAs 510 to 550 may represent a time axis. In addition, the vertical axis for the first to fifth STAs 510 to 550 may indicate the backoff time to be transmitted.

Referring to FIGS. 4 and 5, if a particular medium changes from an occupy or busy state to an idle state, a plurality of STAs may attempt to transmit data (or frames).

In order to minimize collision between STAs, each STA selects a backoff time Tb [i] of Equation (1), waits for a corresponding slot time, You can try.

When the backoff procedure is initiated, each STA may count down the individually selected backoff counter time in slot time units. Each STA can continuously monitor the media during the countdown.

If the wireless medium is monitored in an occupied state, the STA can stop and wait for the countdown. If the wireless medium is monitored in an idle state, the STA may resume the countdown.

Referring to FIG. 5, when the frame for the third STA 530 reaches the MAC layer of the third STA 530, the third STA 530 can check whether the medium is idle during DIFS. Then, if the medium is determined to be idle during the DIFS, the third STA 530 may transmit the frame to the AP (not shown). It should be understood that although the interframe space (IFS) of FIG. 5 is shown as DIFS, the present disclosure is not limited thereto.

While the frame is being transmitted from the third STA 530, the remaining STAs can check the occupancy state of the medium and wait for the transmission period of the frame. The frame can reach the MAC layer of each of the first STA 510, the second STA 520, and the fifth STA 550. If the medium is identified as idle, each STA can wait for the DIFS and count down the individual backoff times selected by each STA.

Referring to FIG. 5, the second STA 520 selects the smallest backoff time and the first STA 510 selects the largest backoff time. The remaining backoff time of the fifth STA 550 at the time point (T1) when the backoff process for the backoff time selected by the second STA 520 is completed and the frame transmission is started, Off time.

When the medium is occupied by the second STA 520, the first STA 510 and the fifth STA 550 can suspend and wait for the backoff procedure. Then, when the medium occupation of the second STA 520 is terminated (i.e., when the medium is idle again), the first STA 510 and the fifth STA 550 can wait for DIFS.

The first STA 510 and the fifth STA 550 may then resume the backoff procedure based on the paused remaining backoff time. In this case, since the remaining backoff time of the fifth STA 550 is shorter than the remaining backoff time of the first STA 510, the fifth STA 550 completes the backoff procedure before the first STA 510 .

5, when a medium is occupied by the second STA 520, a frame for the fourth STA 540 may reach the MAC layer of the fourth STA 540. [ When the medium is idle, fourth STA 540 may wait for DIFS. The fourth STA 540 may then count down the backoff time selected by the fourth STA 540.

Referring to FIG. 5, the remaining backoff time of the fifth STA 550 may coincide with the backoff time of the fourth STA 540. In this case, a collision may occur between the fourth STA 540 and the fifth STA 550. If a collision occurs between STAs, neither the fourth STA 540 nor the fifth STA 550 receives an ACK and may fail to transmit data.

Accordingly, the fourth STA 540 and the fifth STA 550 can individually compute a new contention window CW _new [i] according to Equation (2) above. Next, the fourth STA 540 and the fifth STA 550 may individually perform the countdown for the newly calculated backoff time according to Equation (2) above.

On the other hand, when the medium is occupied due to the transmission of the fourth STA 540 and the fifth STA 550, the first STA 510 can wait. Then, when the medium becomes idle, the first STA 510 may wait for DIFS and resume back-off counting. When the remaining backoff time of the first STA 510 has elapsed, the first STA 510 can transmit the frame.

The CSMA / CA mechanism may also include virtual carrier sensing in addition to physical carrier sensing in which the AP and / or STA directly senses the media.

Virtual carrier sensing is intended to compensate for problems that may arise from media access, such as hidden node problems. For virtual carrier sensing, the MAC of the WLAN system uses a network allocation vector (NAV). The NAV is a value indicating to another AP and / or the STA that the AP and / or the STA that is currently using or authorized to use the medium has remaining time until the media becomes available.

Therefore, the value set to NAV corresponds to the period in which the medium is scheduled to be used by the AP and / or the STA that transmits the frame, and the STA receiving the NAV value is prohibited from accessing the medium during the corresponding period. The NAV may be set according to the value of the duration field of the MAC header of the frame, for example.

6 is a conceptual diagram of a wireless terminal for transmitting a frame in the wireless LAN system according to the present embodiment.

6, the wireless terminal 600 according to the present embodiment includes a virtual mapper 610, a plurality of transmission queues 620 to 650, a virtual collision processor 660, and a plurality of directional antenna modules 670a to 670n. . ≪ / RTI >

6, the description of the virtual mapper 610, the plurality of transmission queues 620 to 650 and the virtual collision processor 660 is the same as that of the virtual mapper 310 of FIG. 3, The queues 320 to 350 and the virtual conflict handler 360. [

According to the embodiment of FIG. 6, the wireless terminal 600 has an internal structure in which a set of transmission queues 620, 630, 640, 650 and a plurality of directional antenna modules 670a through 670n within the wireless terminal are associated .

A DMG (Directional Multi-Gigabit) antenna according to the present embodiment may include a plurality of physical antennas. In addition, the DMG antenna according to the present embodiment can be understood as a set of a plurality of physical (or logical) antennas arranged in one direction.

The first directional antenna module 670a includes a first DMG antenna associated with a first user terminal (not shown), and the second directional antenna module 670b includes a second directional antenna module 670b, And a second DMG antenna associated with the second DMG antenna (not shown).

Also, the third directional antenna module 670c may include a third DMG antenna associated with a third user terminal (not shown), and the N-directional antenna module 770n (n is a natural number) may include an Nth STA And N is a natural number).

Hereinafter, it is assumed that the wireless terminal 600 of FIG. 6 includes five directional antenna modules 670a through 670e. The wireless terminal 600 of FIG. 6 further includes a plurality of data frames 621 (641 to 643) based on a receive address (hereinafter, referred to as 'RA') set in each of a plurality of data frames 621, 631 to 634, , 631 to 634, and 641 to 643 and a plurality of directional antenna modules 670a to 670n.

The first data frame 621 may be buffered in the transmission queue 620 of the AC VO type. For example, the first data frame 621 may be understood as an MPDU including received address (RA) information indicating a first user terminal (not shown).

The second to fifth data frames 631 to 634 may be buffered in the transmission queue 630 of the AC VI type. For example, the second to fourth data frames 631, 632, and 633 may be understood as MPDUs including received address (RA) information indicating a second user terminal (not shown). For example, the fifth data frame 634 may be understood as an MPDU including received address (RA) information indicating a first user terminal (not shown).

The sixth to eighth data frames 641 to 643 may be buffered in the transmission queue 640 of the AC BE type. For example, the sixth data frame 641 may be understood as an MPDU including received address (RA) information indicating a third user terminal (not shown).

For example, the seventh data frame 642 may be understood as an MPDU including received address (RA) information indicating a fourth user terminal (not shown). For example, the eighth data frame 643 may be understood as an MPDU including the received address (RA) information indicating a fifth user terminal (not shown).

It is to be understood that the plurality of data frames included in the transmission queue mentioned with reference to FIG. 6 is only an example, and the present specification is not limited thereto.

The buffered data frames in the plurality of transmission queues according to the present embodiment may be transmitted through the respective directional antenna modules 670a to 670n according to the reception address information RA included in each data frame.

For example, the first data frame 621 and the fifth data frame 634 may be transmitted via the first directional antenna module 670a. The second to fourth data frames 631, 632, and 633 may be transmitted through the second directional antenna module 670b.

The sixth data frame 641 may be transmitted via the third directional antenna module 670c. The seventh data frame 642 may be transmitted via the fourth directional antenna module 670d. The eighth data frame 643 may be transmitted via the fifth directional antenna module 670e.

An existing wireless terminal can perform a non-directional clear channel assessment (CCA) procedure. Specifically, the existing STA determines the state of the wireless medium by comparing a power level of a signal received for a predetermined time (for example, DIFS) from a physical layer of the wireless terminal according to an omnidirectional scheme to a predetermined threshold level .

For example, if the power level of a signal received from the physical layer is lower than a threshold level, the state of the wireless medium may be determined to be in an idle state. If the power level of the signal received from the physical layer is higher than the threshold level, the state of the wireless medium may be determined to be busy.

The wireless terminal 600 according to the present embodiment may cover a plurality of directions associated with the plurality of directional antenna modules 670a through 670n in a directional manner. Specifically, the wireless terminal 600 may perform an individual directional CCA procedure for a plurality of radio channels corresponding to a plurality of directions for a predetermined time.

That is, the wireless terminal 600 may separately determine the status of a plurality of wireless channels associated with the plurality of directional antenna modules 670a through 670n for a plurality of user terminals (not shown).

Hereinafter, the CCA operation performed simultaneously by a wireless terminal according to the present embodiment in a plurality of directions may be referred to as a directional clear channel assessment (CCA) procedure.

Each of the plurality of directional antenna modules 670a through 670n may be associated with a wireless channel in a particular direction for each user terminal (not shown).

The wireless terminal according to the present embodiment can simultaneously perform a plurality of individual directional CCA procedures according to a directional method. That is, the first wireless channel is determined to be in a busy state through the first directional CCA procedure for the first direction among the plurality of directions, and the second wireless channel is determined through the second directional CCA procedure for the second direction, it can be judged that it is in an idle state.

Similarly, the Nth wireless channel in the N-th direction for the Nth user terminal (not shown) through the directional CCA procedure may be determined as an idle state (or busy state).

The wireless terminal according to the present embodiment transmits data (or a data frame) included in a transmission queue of the primary AC based on at least one directional antenna module associated with at least one wireless channel determined to be in an idle state .

In addition, the wireless terminal according to the present embodiment may transmit the data frame included in the transmission queue of the primary AC and the transmission of the secondary AC based on the at least one directional antenna module associated with the at least one wireless channel determined to be in an idle state. The data (or data frame) contained in the queue can be transmitted together.

Also, although not mentioned in the description associated with FIG. 6, the plurality of directional antenna modules 670a through 670n may be used to receive wireless signals transmitted from other wireless terminals.

It is to be understood that the internal structure of the wireless terminal shown in FIG. 6 is only an example, and that the wireless terminal of the present specification can be implemented based on a structure in which a plurality of sets of transmission queues correspond to a plurality of antenna modules.

FIG. 7 is a diagram illustrating a plurality of channels channelized for frame transmission in the wireless LAN system according to the present embodiment.

The abscissa of FIG. 7 may represent the frequency (GHz) for the 60 GHz band. The vertical axis of FIG. 7 may indicate the level (dBr) of the signal relative to the maximum spectral density.

Referring to FIG. 7, in order to support the transmission / reception operation of the wireless terminal according to the present embodiment in the 60 GHz band, the first to sixth channels (ch # 1 to ch # 6) have. For example, the channel spacing for each of the first to sixth channels (ch # 1 to ch # 6) may be 2,160 MHz.

The channel center frequency for each of the first to sixth channels (ch # 1 to ch # 6) according to the present embodiment may be defined based on Equation (3). For example, the channel starting frequency may be 56.16 GHz.

According to Equation (3), the first channel center frequency fc1 for the first channel (ch # 1) may be 58.32 GHz. For example, the first channel (ch # 1) of FIG. 7 may be defined between 57.24 GHz and 59.40 GHz.

According to Equation (3), the second channel center frequency fc2 for the second channel (ch # 2) may be 60.48 GHz. For example, the first channel (ch # 2) of FIG. 7 may be defined between 59.40 GHz and 61.56 GHz.

According to Equation (3), the third channel center frequency fc3 for the third channel (ch # 3) may be 62.64 GHz. For example, the third channel (ch # 3) of FIG. 7 may be defined between 61.56 GHz and 63.72 GHz.

According to Equation (3), the fourth channel center frequency fc4 for the fourth channel (ch # 4) may be 64.80 GHz. For example, the fourth channel (ch # 4) of FIG. 7 may be defined between 63.72 GHz and 65.88 GHz.

According to Equation (3), the fifth channel center frequency fc5 for the fifth channel (ch # 5) may be 66.96 GHz. For example, the fifth channel (ch # 5) of FIG. 7 may be defined between 65.88 GHz and 68.04 GHz.

According to Equation (3), the sixth channel center frequency fc6 for the sixth channel (ch # 6) may be 69.12 GHz. For example, the sixth channel (ch # 6) of FIG. 7 may be defined between 68.04 GHz and 70.2 GHz.

More detailed information on channelization and channel numbering referred to herein may be found in section 19.3.15 of IEEE Draft P802.11-REVmc ™ / D8.0, And 21.3.1 and 21.3.2 and Annex E of IEEE Std 802.11ad ™,

The wireless terminal according to the present specification can transmit a frame based on the wireless channel allocated for each of the plurality of antenna modules 670a to 670n in FIG. 6 mentioned above. Here, the wireless channel can be understood as a multi-channel in which a channel bonding technique or a channel aggregation technique is applied to the plurality of channels Ch # 1 to Ch # 6 in FIG.

 Hereinafter, in order to improve the performance of the wireless LAN system, a procedure for informing bandwidth information for a wireless channel to which channel bonding or channel aggregation is applied using a control trailer will be described.

FIG. 8 is a diagram illustrating a format of an Enhanced Directional Multi-Gigabit (EDMG) PPDU according to the present embodiment.

In this specification, an EDMG PPDU 800 for transmitting buffered data for a plurality of recipients may be referred to as an EDMG MU PPDU (Enhanced Directional Multi-Gigabit Multi-User Physical Protocol Data Unit).

8, an EDMG PPDU 800 includes a field corresponding to a non-EDMG portion (e.g., 810 to 830 in FIG. 8) and a field corresponding to an EDMG portion (e.g., an EDMG portion) 840 to 890 of FIG. 8).

Specifically, fields corresponding to the non-EDMG portion (e.g., 810 to 830 in FIG. 8) are used to detect the EDMG PPDU 800 and to acquire the carrier frequency and timing Can be used.

As an example, the L-STF field 810 can be understood as a field for packet detection of a non-EDMG portion.

For example, the L-CEF field 820 can be understood as a field for channel estimation of a non-EDMG portion.

For example, the L-header field 830 may include a plurality of fields as shown in Table 3 below.

Specifically, the EDMG PPDU 800 has a field corresponding to the EDMG portion (e.g., 840 to 890 in FIG. 8) of the PSDU transmitted through the 2.16 GHz channel, the 4.32 GHz channel, the 6.48 GHz channel, and the 8.64 GHz channel And may be used for estimation of a MIMO channel to support demodulation.

As an example, the EDMG header-A field 840 may contain various information required for the interpretation of the EDMG PPDU.

If the EDMG PPDU is an EDMG control mode PPDU, a plurality of contents of the EDMG header-A field 840 are partitioned between a first LDPC (low-density parity-check) codeword and a second LDPC codeword partition.

The content included in the first LDPC codeword may be referred to as an EDMG header A1 (EDMG-Header-A1) subfield. For example, the EDMG header A1 subfield may be composed of six octets. For example, the EDMG header A1 subfield may include information on bandwidth for a plurality of channels (e.g., 2.16 GHz channels) to which the EDMG PPDU is to be transmitted, information on the primary channel, information on the length of the PSDU included in the EDMG PPDU , Information on the length of the TRN field 890, and the like.

The content included in the second LDPC codeword may be referred to as an EDMG header A2 (EDMG-Header-A2) subfield. For example, the EDMG header A2 subfield may be composed of three octets. For example, the EDMG header A2 subfield may include information on the number of transmission chains used for transmission of EDMG PPDUs and information on CRC (Cyclic Redundancy Check).

If the EDMG PPDU is an EDMG MU PPDU, the EDMG header-A field 840 may include information on channel aggregation, information on bandwidth, information on the primary channel, and information on the type of LDPC coding .

As an example, the EDMG-STF field 850 can be understood as a field for packet detection of the EDMG portion (EDMG portion). For example, the EDMG-STF field 850 may exist in the EDMG PPDU 800 only in the case of transmission of the EDMG SC mode PPDU and transmission of the EDMG OFDM mode PPDU.

For example, the EDMG-CEF field 860 can be understood as a field for channel estimation of the EDMG portion (EDMG portion). For example, the EDMG-CEF field 860 may exist in the EDMG PPDU 800 only in the case of transmission of the EDMG SC mode PPDU and transmission of the EDMG OFDM mode PPDU.

For example, the EDMG header-B field 870 can be understood as a field included only when the EDMG PPDU is an EDMG MU PPDU. The EDMG header-B field 870 may be transmitted on an STA basis for an EDMG MU PPDU.

For example, the EDMG header-B field 870 may include information on the length of the PSDU included in the data field 880, and information on a base MCS (Base MCS).

In one example, the data field 880 may carry a PSDU. The PSDU included in the data field 880 may correspond to the payload.

As an example, the TRN (Training Sequence) field 890 may include information enabling transmit and receive antenna training (AWV training) by a plurality of STAs.

7 and 8, when a channel bonding scheme is applied for a multi-channel for a wireless terminal, a plurality of channels adjacent to each other on the frequency among the first to sixth channels (ch # 1 to ch # 6) .

Also, when a channel aggregation scheme is applied to a multi-channel for a wireless terminal, a plurality of channels separated on the frequency among the first to sixth channels (ch # 1 to ch # 6) may be used.

FIG. 9 shows the format of an EDMG group ID set element according to the present embodiment.

Referring to FIG. 9, an EDMG group ID set element 900 may include a plurality of fields 910,... 950_1 to 950_N.

To perform DL MU-MIMO beamforming and DL MU-MIMO transmission, the EDMG group ID set element 900 may allow the AP to define a group of multiple STAs capable of MU transmission.

For example, the EDMG group ID set element 900 may be transmitted in a DMG beacon frame or a DMG announce frame.

In the element ID field 910, a value indicating the EDMG group ID set element 900 may be set based on one octet.

In the length field 920, a value indicating the length of the EDMG group ID set element 900 may be set based on one octet.

An element ID extension field 930 may be assigned one octet.

A value for indicating the number of the EDMG group fields 950_1 to 950_N based on one octet may be set in the EDMG group number field 940. [

EDMG group fields 950_1 to 950_N may be included as many as the number of STAs to be subjected to DL MU-MIMO beamforming and DL MU-MIMO transmission. The format of each of the subfields of the EDMG group fields 950_1 to 950_N will be described in more detail with reference to FIG.

FIG. 10 shows the format of the EDMG group field included in the EDMG group ID set element according to the present embodiment.

Referring to FIGS. 9 and 10, the plurality of subfields 1000 of FIG. 10 may be understood to correspond to any one of a plurality of EDMG group fields 950_1 to 950_N.

A unique nonzero value for identifying a corresponding one of the plurality of groups may be set in the EDMG group ID subfields (B0-B7).

In the group size subfields (B8-B12), a value indicating the number of EDMG STAs belonging to the corresponding group may be set. In this case, an association identifier (AID) of the EDMG STA belonging to the corresponding group may be included in the subsequent sub-field.

The reserved subfields (B13-B15) can be set to 3 bits.

The AID value of each EDMG STA belonging to the corresponding group can be set in each of the AID subfields B24-B31 to B (8 * (N + 1)) -B (8 * (N + 2) -1) .

11 and 12 show the format of the EDMG group field included in the EDMG group ID set element according to the present embodiment.

MU-MIMO < / RTI > beamforming protocol.

The MU-MIMO beamforming protocol according to the present embodiment includes an MU-MIMO capable initiator and one or more MU-MIMO capable responders in the MU group an MU group can establish an antenna configuration.

Here, the antenna configuration allows the initiator to transmit the EDMG MU PPDU to a plurality of responders belonging to the MU group, so that mutual interference between streams transmitted in the MU PPDU is minimized.

The MU-MIMO beamforming protocol may be initiated by the initiator. The MU-MIMO beamforming protocol can be controlled by the initiator. The MU-MIMO beamforming protocol consists of the SISO phase and the MIMO phase.

The MU-MIMO beamforming protocol may be executed based on the EDMG Group ID Set element transmitted by the AP or PCP of the BSS.

The AP or PCP must transmit the EDMG group ID set element before performing the MU-MIMO beamforming protocol. The EDMG group ID set element may contain all groups present in the BSS. The EDMG STA may store the information contained in the most recently received EDMG group ID set element.

Referring to FIG. 11, there is shown a SISO step for an MU-MIMO beamforming protocol.

The goal of the SISO phase (SISO phase) is to collect feedback for the TX antenna of one or more suitable initiators and the responder's RX DMG. In addition, the goal of the SISO step is to collect feedback on the sectors between the initiator and each intended responder. Here, each responder can be understood as a part of an MU group.

The information obtained through the SISO step can be used to perform the next MIMO step. For reference, all transmissions during the SISO phase should use the DMG control mode.

The SISO step of FIG. 11 may consist of an I-TXSS subphase and a SISO feedback sub-step.

Referring to FIG. 11, the initiator may selectively perform the I-TXSS sub-steps. Through the I-TXSS sub-step, the initiator can obtain feedback for one or more sectors for each initiator's TX DMG antenna from a plurality of responders in the MU group.

For example, the initiator may use the Short SSW packet to perform the I-TXSS sub-steps.

For example, in each Short SSW packet transmitted as part of the I-TXSS, the Direction field is set to '0' and an Addressing Mode field is set to indicate MU-MIMO .

Also, in each Short SSW packet transmitted as part of the I-TXSS, the Destination AID field may be set to include the group ID announced by the PCP or AP in the last transmitted EDMG group ID set element have.

Also, in each Short SSW packet transmitted as part of the I-TXSS, the CDOWN field may be set to the number of short SSW packets remaining to the end of the I-TXSS sub-step. In addition, the Setup Duration field may be set to the duration of the next SISO Feedback sub-step.

The MU-MIMO capable EDMG STA receiving the short SSW packet indicating the MU-MIMO transmission can determine whether the value of the destination AID field of the packet matches the value of the EDMG group ID field stored in advance. According to the above determination, the EDMG STA can determine whether it is the intended recipient of the packet.

Here, the value of the EDMG group ID field can be understood as a value included in the most recently received EDMG group ID set element.

If it is determined that the value of the destination AID field of the packet does not match the value of the EDMG group ID field, the EDMG STA may determine that it is not the intended recipient of the packet. Accordingly, the EDMG STA can ignore the remaining I-TXSS and SISO feedback subfields.

Referring to FIG. 11, the initiator may perform the SISO feedback sub-step mandatory. If there is an I-TXSS sub-step, the SISO feedback sub-step may start after the MBIFS from the end of the I-TXSS sub-step.

During the SISO feedback sub-step, the initiator may send a BRP frame for polling each responder belonging to the MU group, to obtain a list of sectors per TX DMG antenna and associated quality indicators between the initiator and the responder.

The responder can then respond with the BRP frame to the received BRP frame. The BRP frame transmitted by the responder may include a sector for each TX DMG antenna of the initiator and a quality indicator for the corresponding sector.

In the SISO feedback sub-step, a BRP frame may be sent in SIFS intervals between the initiator and the responder.

Referring to FIG. 12, a downlink MIMO step of a MIMO step for an MU-MIMO beamforming protocol is shown.

The MIMO phase (MIMO phase) may include a downlink MIMO phase or an uplink MIMO phase.

For example, the downlink MIMO step may be supported by all EDMG STAs capable of MU-MIMO. The uplink MIMO step may be supported by an EDMG STA capable of MU-MIMO.

The downlink initiator may start the MIMO phase after the MBIFS has elapsed since the end of the SISO phase.

Referring to FIG. 12, the downlink MIMO phase may include four sub-steps. For example, each substep can be separated according to MBIFS.

The downlink MIMO step includes an MU-MIMO BF setup sub-step, an MU-MIMO BF training sub-step, an MU-MIMO BF feedback sub-step, subphase) and an MU-MIMO BF selection subphase (MU-MIMO BF selection subphase).

For example, in the MU-MIMO BF setup sub-step, if the multiuser interference expected by the responder due to the MU-MIMO transmission is negligible based on the feedback obtained in the SISO step, -MIMO BF training sub-step and the MU-MIMO BF feedback sub-step.

For example, in the MU-MIMO BF training sub-step, the initiator may send one or more EDMG BRP-RX / TX packets to the remaining responder of the MU group. Each EDMG BRP-RX / TX packet can be separated in SIFS intervals. Each EDMG BRP-RX / TX packet may be used to train one or more transmit sectors and a plurality of receive antenna weight vectors (AWV) for each transmit sector.

For example, the MU-MIMO BF feedback sub-step may be performed after the transmission of the EDMG BRP RX-TX packet with the BRP CDOWN field set to '0', after the MBIFS has elapsed.

In one example, in order to collect MU-MIMO BF feedback from the preceding MU-MIMO BF training sub-step in the MU-MIMO BF feedback sub-step, the initiator sets a Poll Type field of MIMO BF Poll frames can be transmitted.

For example, in the MU-MIMO BF selection sub-step, the initiator may send a MIMO BF selection frame to each responder in the MU group. For example, the MIMO BF selection frame may include a dialog token that identifies the MU-MIMO BF training, one or more sets of MU transmission configurations, and an intention for each MU transmission configuration (STAs for each MU transmission configuration).

The final set of selected responders in the MU group included in the MIMO BF selection frame need not be the same as the initial set of intended responders. The initiator may send a minimum number of MIMO BF selection frames to the selected responder.

13 is a conceptual diagram showing a configuration of an EDMG group according to the present embodiment and a wireless LAN system after performing an MU-MIMO beamforming protocol.

1 to 13, it can be assumed that an AP and a plurality of STAs (for example, STA # 1 to STA # 4) belong to one BSS. Further, it can be assumed that a plurality of STAs (for example, STA # 1 to STA # 4) belong to one EDMG group.

13, the AP of FIG. 13 may transmit an EDMG group ID set element (e.g., 900 of FIG. 9) to a non-directional region 1300 before performing the MU-MIMO beamforming protocol .

According to the above assumption, the EDMG group ID set element (for example, 900 in FIG. 9) stores information for one EDMG group corresponding to the first to fourth STAs (for example, STA # 1 to STA # 4 in FIG. 13) .

For example, a value (4 ') corresponding to the number of the first to fourth STAs (e.g., STA # 1 to STA # 4) in FIG. 13 corresponds to the value of the EDMG group ID set element Group size subfield (e.g., B8-B12 in Fig. 10).

The AID value corresponding to each of the first to fourth STAs (e.g., STA # 1 to STA # 4) in FIG. 13 may be a plurality of AID subfields of the EDMG group ID set element (e.g., 900 in FIG. 9) , And B24-B31 to B (8 * (N + 1)) -B (8 * (N + 2) -1) in FIG.

Here, the first to fourth STAs (e.g., STA # 1 to STA # 4) in FIG. 13 include a plurality of groups indicated by EDMG group ID set elements (for example, 900 in FIG. 9) Can be stored.

(E.g., STA # 1 in FIG. 13), a third STA (e.g., STA # 3 in FIG. 13), an EDMG group ID set element ) And a second STA (e.g., STA # 2 in FIG. 13).

In general, exchange sequences for an EDMG MU PPDU may be determined according to the order of a plurality of AID values included in an EDMG group ID set element (e.g., 900 in FIG. 9).

For example, the first to third STAs (e.g., STA # 1 to STA # 3) in FIG. 13 include a block ACK frame for an EDMG MU PPDU as a first STA (e.g., STA # 1 in FIG. 13) (STA # 3 in FIG. 13) and the second STA (STA # 2 in FIG. 13, for example).

For example, without further signaling to the first to third STAs (e.g., STA # 1 to STA # 3) of Figure 13 after transmission of the EDMG group ID set element (e.g., 900 of Figure 9), the EDMG MU PPDU , STA # 3 in FIG. 13) and the third STA (for example, STA # 1 in FIG. 13) are sequentially included in the preamble of the first STA 2 STA < / RTI > (e.g., STA # 2 in FIG. 13).

After the execution of the MU-MIMO Beamforming protocol according to FIG. 11 and FIG. 12, the AP of FIG. 13 transmits the first to third STAs (STA # 1 to STA # 3, for example) To third sectors 1310, 1320, and 1330, respectively.

For example, the AP may transmit an EDMG MU PPDU (e.g., 800 of FIG. 8) based on the first through third sectors 1310, 1320, 1330.

For example, each of the first to third sectors 1310, 1320, and 1330 may perform channel bonding or channel aggregation based on the plurality of channels (ch # 1 to ch # 6) Lt; / RTI >

13, the block ACK frame for notifying the successful reception of the A-MPDU addressed to the first STA (STA # 1) is based on a separate directivity area (not shown) different from the first sector 1310 AP. ≪ / RTI >

In addition, the block ACK frame for informing the successful reception of the A-MPDU addressed to the second STA (STA # 2) of FIG. 13 is transmitted to the AP 120 based on a separate directivity area (not shown) Lt; / RTI >

Similarly, the block ACK frame for informing the successful reception of the A-MPDU addressed to the third STA (STA # 3) of FIG. 13 is transmitted to the AP 130 based on a separate directivity area (not shown) different from the third sector 1330 Lt; / RTI >

FIG. 14 is a diagram illustrating a method of performing an operation according to a power save mode in a wireless LAN system according to the present embodiment.

The MU-MIMO power save mechanism may allow a non-AP STA (or non-PCP EDMG STA) in the infrastructure BSS to enter the PS mode during the TXOP interval. Here, the non-AP STA (or the non-PCP EDMG STA) can be understood as a wireless terminal involved in the MU-MIMO transmission and acknowledgment procedure.

For example, an EDMG STA in an awake state may receive an EDMG MU PPDU from an AP depending on the operation of the PS mode. As another example, an EDMG STA in the doze state according to the operation of the PS mode can not receive the EDMG MU PPDU from the AP.

EDMG MU An EDMG STA receiving a plurality of A-MPDUs in a PPDU can enter the PS mode during the following two types of periods.

The first type of time interval is the time from the detection of the EOF (End of Field) field in the individual A-MPDU for each EDMG STA in the EDMG MU PPDU to the beginning of each EDMG STA to perform the BAR / BA exchange with the initiator Time interval.

The second type of time interval may correspond to a period from the successful transmission of the BA to the end of frame exchange of the current EDMG MU PPDU.

When determining the time to wake up before performing the BAR / BA exchange with the initiator, the EDMG STA may use the most conservative estimate so as not to miss the corresponding BAR / BA exchange with the initiator.

For example, an EDMG STA may assume that the other initiator-responder pairs in the same MU group use the highest MCS value that can perform the BAR / BA exchange with the initiator. And, the EDMG STA can assume that the BAR / BA frame size used between the other initiator-responder pairs is the shortest size.

Once the EDMG STA wakes up, the EDMG STA may be in an awake state until it receives a BAR frame addressed to it and reaches the first of the time of transmitting the BA frame to the initiator or the end of the current TXOP.

Also, after the EDMG STA sends back the BA frame to the initiator, the EDMG STA can maintain the awake state for an additional AckTimeout interval to account for retransmission of the BAR frame possible from the initiator.

Referring to FIGS. 1-14, the AP 1400 may correspond to the AP in FIG. For example, the horizontal axis ta of the AP 1400 may be associated with the time resources of the AP 1400. The vertical axis of AP 1400 may be associated with the presence of a frame transmitted by AP 1400.

The first STA 1410 may correspond to STA # 1 in FIG. For example, the horizontal axis tl of the first STA 1410 may be associated with the time resources of the first STA 1410. [ The vertical axis of the first STA 1410 may be associated with the presence of a frame transmitted by the first STA 1410.

The second STA 1420 may correspond to STA # 2 in FIG. For example, the horizontal axis t2 of the second STA 1420 may be associated with the time resources of the second STA 1420. The vertical axis of the second STA 1420 may be associated with the presence of a frame transmitted by the second STA 1420.

The third STA 1430 may correspond to STA # 3 in FIG. For example, the horizontal axis t3 of the third STA 1430 may be associated with the time resources of the third STA 1430. [ The vertical axis of the third STA 1430 may be associated with the presence of a frame transmitted by the third STA 1430.

14, the AP 1400 can transmit the EDMG MU PPDU to the plurality of STAs 1410, 1420 and 1430. [

Here, the AP 1400 can be understood as a terminal that has acquired a transmission opportunity (TXOP) for a wireless channel through a channel competition with another STA. For example, the AP 1400 in FIG. 14 may occupy the wireless medium during the TXOP interval (e.g., T1 through T12 in FIG. 14).

For example, the EDMG MU PPDU of FIG. 14 includes a plurality of A-MPDUs (A-MPDU # 1, A-MPDU # 2, A-MPDU # 3) having the same length transmitted on the preamble and overlapped time resource can do.

For example, the preamble of FIG. 14 may correspond to a field region (e. G., 810-870 of FIG. 8) prior to a data field of an EDMG PPDU (e.g., 800 of FIG. 8).

For example, a first A-MPDU (i.e., A-MPDU # 1 in FIG. 14) may include a plurality of data fields (e.g., 880) for a first wireless terminal A first data area and a first padding area (hatched portion).

For example, a second A-MPDU (i.e., A-MPDU # 2 in FIG. 14) may include a plurality of data fields (e.g., 880) for a second wireless terminal A second data area, and a second padding area (hatched portion).

For example, a third A-MPDU (i.e., A-MPDU # 3 in FIG. 14) may include a plurality of data fields (e.g., 880) for a third wireless terminal And a third data area.

It will be appreciated that, in the present embodiment, a block ACK frame (i.e., a BA frame) may be used to indicate whether a plurality of data fields in each A-MPDU are successfully received for the aggregated data area.

In particular, the preamble of FIG. 14 may include a plurality of EDMG header-B fields for a plurality of wireless terminals.

As mentioned above, each wireless terminal can identify its EDMG header-B field even if there is no additional signaling in the order of a plurality of AID values included in the EDMG group ID set element (e.g., 900 in FIG. 9) have.

According to the present embodiment, the EDMG header-B field (e.g., 870 in FIG. 8) for each wireless terminal includes information on the transmission order of the block ACK frame for notifying successful reception of the A-MPDU for each wireless terminal . That is, the transmission order of the block ACK frame may be included in the MU acknowledgment order field as shown in Table 4 below.

According to the present embodiment, the MU acknowledgment order field of Table 4 can be set such that the block ACK frame is sequentially transmitted according to the length of the data area of a plurality of A-MPDUs included in the EDMG MU PPDU.

For example, an AP that is an initiator is a block ACK for an A-MPDU having a longest data area (for example, A-MPDU # 3 in FIG. 14) among a plurality of A-MPDUs included in an EDMG MU PPDU The MU acknowledgment order field of Table 4 can be set such that the frame is transmitted first.

For example, the MU acknowledgment order field for the third wireless terminal (i.e., 1430) may be set to '0'.

Also, the initiating AP may set the ACK policy for the A-MPDU having the longest data area length (for example, A-MPDU # 3 in FIG. 14) to the immediate ACK.

For example, an AP that is an initiator may be an A-MPDU having a length of a data area of a second A-MPDU (for example, A-MPDU # 2 in FIG. 14) among a plurality of A-MPDUs included in an EDMG MU PPDU The MU acknowledgment order field of Table 4 can be set such that the block ACK frame is transmitted a second time.

For example, the MU acknowledgment order field for the second wireless terminal (i.e., 1420) may be set to '1'.

Also, the initiating AP may set the ACK policy for the second longest A-MPDU (e.g., A-MPDU # 2 in FIG. 14) to no immediate ACK.

For example, an AP that is an initiator is a block ACK for an A-MPDU (for example, A-MPDU # 1 in FIG. 14) having the shortest data area length among a plurality of A-MPDUs included in an EDMG MU PPDU The MU acknowledgment order field in Table 4 can be set so that the frame is transmitted the latest.

For example, the MU acknowledgment order field for the first wireless terminal (i.e., 1410) may be set to '2'.

Also, the initiating AP may set the ACK policy for the A-MPDU having the shortest data area length (for example, A-MPDU # 1 in FIG. 14) to no immediate ACK.

The remaining sections T2 to T12 after the first section T1 to T2 of FIG. 14 will be described in detail with reference to FIG. 15 which will be described later.

According to the present embodiment, regardless of the order of a plurality of AID values included in the aforementioned EDMG group ID set element (for example, 900 in FIG. 9), the MU acknowledgment included in the EDMG header-B field for each wireless terminal the transmission order of the block ACK frame may be determined according to the order field.

According to the present embodiment, the power save operation can be efficiently supported by adjusting the standby power of the wireless terminal more flexibly according to the communication environment of the wireless LAN system.

15 is a flowchart illustrating a method of performing an operation according to a power save mode in a wireless LAN system according to the present embodiment.

13 and 15, it can be assumed that the AP in FIG. 15 corresponds to the AP in FIG. 13, and the first STA in FIG. 15 corresponds to STA # 1 in FIG. It is also assumed that the second STA in FIG. 15 corresponds to STA # 2 in FIG. 13, and the third STA in FIG. 14 corresponds to STA # 3 in FIG.

It is also assumed that the first to third STAs referred to in FIG. 15 operate according to a power save (PS) mode. In addition, it is assumed that the first to third STAs referred to in FIG. 15 are initially in the awake state for the reception operation of the EDMG MU PPDU (Enhanced Directional Multi-Gigabit Multi-User Physical Protocol Data Unit).

It can be assumed that the EDMG MU PPDU (Enhanced Directional Multi-Gigabit Multi-User Physical Protocol Data Unit) referred to in FIG. 15 corresponds to the EDMG MU PPDU transmitted in the first interval T1 to T2 in FIG.

In step 1510, the first STA (e.g., 1410 in FIG. 14) may perform a receive operation on the EDMG MU PPDU. For reference, it will be appreciated that the second and third STAs (e.g., 1420, 1430 in FIG. 14) may also perform a receive operation on the EDMG MU PPDU.

For example, an EDMG MU PPDU may be received from an AP (e.g., 1400 in FIG. 14).

For example, the EDMG MU PPDU may include a plurality of A-MPDUs (e.g., A-MPDU # 1 to A-MPDU # 3 of FIG. 14) having the same length transmitted on the preamble and overlapping time resources.

For example, each of the plurality of A-MPDUs may include data lengths of different lengths for each of a plurality of recipients (e.g., 1410, 1420, 1430 of FIG. 14). That is, it will be understood that a padding area may be added after the data area such that a plurality of A-MPDUs have the same length.

According to the present embodiment, the transmission order of the BA frames for each A-MPDU can be determined according to the length of the data area included in each A-MPDU.

For example, the preamble of the EDMG MU PPDU includes a first STA (e.g., 1410 of FIG. 14) of a plurality of A-MPDUs (e.g., A-MPDU # Order information on the transmission order of the block ACK frame (i.e., the BA frame) for the A-MPDU (for example, A-MPDU # 1 in FIG. 14).

Referring to FIG. 14, the data area of the first A-MPDU (for example, A-MPDU # 1 in FIG. 14) among a plurality of A-MPDUs (for example, A-MPDU # 1 to A- Is the shortest. For reference, in order to match the length with the A-MPDU having the longest data area (for example, A-MPDU # 3 in FIG. 14), the data area of the first A-MPDU (for example, A- The padding area may then be appended.

In this case, the first order information may include a value indicating that the block ACK frame for the first A-MPDU (for example, A-MPDU # 1 in FIG. 14) is transmitted latest. That is, the first order information is set in the MU acknowledgment order field among the plurality of subfields in Table 4 included in the EDMG header-B field (e.g., 870 in FIG. 8) for the first STA .

In other words, a value corresponding to '2' is set in the subfield of the EDMG header-B field (not shown) for the first STA (e.g., 1410 in FIG. 14) (i.e., MU acknowledgment order # 1 in FIG. 14) .

Also, the ACK policy for the first A-MPDU (e.g., A-MPDU # 1 in FIG. 14) may be set to no immediate ACK. That is, the first STA (e.g., 1410 of FIG. 14) may only transmit a BA frame when a BAR frame is received from an AP (e.g., 1400 of FIG. 14).

For example, the preamble may include a second A-MPDU (e.g., A-MPDU # 1 to A-MPDU # 3) addressed by a second STA (e.g., 1420 of Figure 14) For example, second order information on the transmission order of the block ACK frame for A-MPDU # 2 in FIG. 14 may be included.

Referring to FIG. 14, the data area of the second A-MPDU (for example, A-MPDU # 2 in FIG. 14) out of the plurality of A-MPDUs (for example, A-MPDU # 1 to A- The length of the second is long. For reference, in order to match the length with the A-MPDU having the longest data area (for example, A-MPDU # 3 in FIG. 14), the data area of the second A-MPDU The padding area may then be appended.

In this case, the second order information may include a value indicating that a BA frame for the second A-MPDU (for example, A-MPDU # 2 in FIG. 14) is transmitted a second time. That is, the second order information is set in the MU acknowledgment order field among the plurality of subfields in Table 4 included in the EDMG header-B field (e.g., 870 in FIG. 8) for the second STA .

In other words, a value corresponding to '1' is set in the subfield of the EDMG header-B field (not shown) for the second STA (for example, 1420 in FIG. 14) (that is, MU acknowledgment order # 2 in FIG. 14) .

Also, the ACK policy for the second A-MPDU (e.g., A-MPDU # 2 in FIG. 14) may be set to no immediate ACK. That is, the second STA (e.g., 1420 of FIG. 14) may only transmit the BA frame when a BAR frame is received from the AP (e.g., 1400 of FIG. 14).

For example, the preamble may include a third A-MPDU (e.g., A-MPDU # 1 to A-MPDU # 3) addressed to a third STA (e.g., 1430 of Figure 14) For example, third order information on the transmission order of BA frames for A-MPDU # 3 in FIG. 14 may be included.

Referring to FIG. 14, the data area of the third A-MPDU (for example, A-MPDU # 3 in FIG. 14) out of a plurality of A-MPDUs (for example, A-MPDU # 1 to A- Is the longest.

In this case, the third order information may include a value indicating that the block ACK frame for the third A-MPDU (for example, A-MPDU # 3 in FIG. 14) is transmitted first. That is, the third order information is set in the MU acknowledgment order field among the plurality of subfields in Table 4 included in the EDMG header-B field (e.g., 870 in FIG. 8) for the third STA .

In other words, a value corresponding to '0' is set in the subfield of the EDMG header-B field (not shown) (i.e., MU acknowledgment order # 3 in FIG. 14) for the third STA .

Also, an ACK policy for the third A-MPDU (e.g., A-MPDU # 3 in FIG. 14) may be set to immediate ACK.

In this case, the third STA (for example, 1430) transmits the EDMG MU PPDU by the AP (e.g., 1400 in FIG. 14) for a certain period of time (for example, T2 to T3, SIFS 14), the third STA (for example, 1430 in Fig. 14) is a third A-MPDU (for example, A-MPDU in Fig. 14) # 3). ≪ / RTI >

In step S1520, the first STA (e.g., 1410 of FIG. 14) may determine whether the transmission order of the BA frame is first based on the first order information included in the preamble of the EDMG MU PPDU.

According to the preceding assumption, the BA frame for the first A-MPDU (e.g., A-MPDU # 1 in Fig. 14) addressed to the first STA (e.g., 1410 in Fig. 14) Step S1530 may be performed.

Likewise, since the transmission order of the block ACK frame for the second A-MPDU (for example, A-MPDU # 2 in FIG. 14) addressed to the second STA (for example, 1420 in FIG. 14) is not the first, Can be performed.

However, since the transmission order of the block ACK frame for the third A-MPDU (for example, A-MPDU # 3 in FIG. 14) addressed to the third STA (for example, 1430 in FIG. 14) is first, .

In step S1530, the first STA (e.g., 1410 in FIG. 14) includes a data area (e.g., A-MPDU # 1) included in an A-MPDU corresponding to the first STA It is possible to determine whether or not the reception of the data is complete.

If it is determined that the reception of the data area included in the A-MPDU (for example, A-MPDU # 1 in FIG. 14) corresponding to the first STA (for example, 1410 in FIG. 14) is not completed, the procedure can be ended.

If it is determined that the reception of the data area included in the A-MPDU (for example, A-MPDU # 1 in FIG. 14) corresponding to the first STA (for example, 1410 in FIG. 14) is completed, the procedure goes to step S1540.

In step S1540, the first STA (for example, 1410 in FIG. 14) according to the present embodiment is configured such that the reception of the first data area included in the first A-MPDU (for example, A-MPDU # 1 in FIG. 14) The power state of the first STA (e.g., 1410) can be switched to a doze state at a first time point (e.g., Tsp1 in FIG. 14).

Also, the first STA (e.g., 1410 in FIG. 14) may obtain information about the time to awaken from the doze state based on the first order information (e.g., T9 in FIG. 14).

14), the first STA (for example, 1410 of FIG. 14) is started at a time point (for example, T9 in FIG. 14) obtained based on the first order information from the time point of switching to the doze state (for example, Can be kept in a dose state.

14) of the second STA according to the present embodiment (for example, 1420 of FIG. 14) receives the second data area included in the second A-MPDU (for example, A-MPDU # 2 of FIG. 14) For example, the power state of the second STA (e.g., 1420 of FIG. 14) may be switched to the doze state to Tsp2 of FIG.

Further, the second STA (for example, 1420 in FIG. 14) may acquire information about a time to awaken from the doze state based on the second order information (for example, T5 in FIG. 14).

14), the second STA (for example, 1420 in FIG. 14) is acquired at a time point (for example, T5 in FIG. 14) obtained based on the second order information from the time point (for example, Tsp2 in FIG. 14) Can be kept in a dose state.

14) of the first STA (for example, 1410 in Fig. 14) according to this embodiment elapses from the first STA (for example, 1410 in Fig. 14) to the awake state.

Although not shown in Fig. 15, in a time interval (for example, T9 to T10 in Fig. 14) after the time point acquired based on the first order information (for example, T9 in Fig. 14), the first STA 1410 may receive a Block Ack Request (BAR) frame from an AP (e.g., 1400 in FIG. 14).

Here, the BAR frame can be understood as a frame requesting transmission of a BA frame for a first A-MPDU (e.g., A-MPDU # 1 in FIG. 14) to a first STA (e.g., 1410 in FIG. 14).

14) of the first STA (for example, 1410 in FIG. 14) elapses after a certain period of time (for example, T10 to T11, SIFS in FIG. 14) The AP frame (e.g., 1400 in Fig. 14) for the A-MPDU (e.g., A-MPDU # 1 in Fig. 14).

14) of the second STA (for example, 1420 in Fig. 14) according to the present embodiment, the second STA (e.g., 1420 in FIG. 14) to an awake state.

Although not shown in FIG. 15, in a time interval (for example, T5 to T6 in FIG. 14) after the time point acquired based on the second order information (for example, T5 in FIG. 14), a second STA 1420 may receive a Block Ack Request (BAR) frame from an AP (e.g., 1400 in FIG. 14).

Here, the BAR frame can be understood as a frame requesting transmission of a BA frame for a second A-MPDU (e.g., A-MPDU # 2 in FIG. 14) to a second STA (e.g., 1420 in FIG. 14).

14) of the second STA (for example, 1420 in Fig. 14) elapses after a certain period of time (e.g., T6 to T7, SIFS in Fig. 14) 14) of the A-MPDU (for example, A-MPDU # 2 in Fig. 14).

Then, when a certain time has elapsed since the transmission of the BA frame for the second A-MPDU (for example, A-MPDU # 2 in FIG. 14), the second STA (1420 in FIG. 14) It is possible to switch to the doze state. In this case, the predetermined time may be understood as a period in which the SIFS and the transmission interval of the BAR frame (for example, T8 to T10 in FIG. 14) are summed.

14), the second STA (e.g., 1420 of FIG. 14) can maintain its power state in a dosed state until the end of the TXOP interval (e.g., T12 in FIG. 14) have.

Step S1560 may be performed when the transmission order of the block ACK frame for the A-MPDU (for example, A-MPDU # 3 in FIG. 14) addressed to the STA (for example, 1430 in FIG. 14) is first.

14) of the A-MPDU (e.g., A-MPDU # 3 in FIG. 14) after the reception operation for the A-MPDU (for example, A- 3) (for example, T2 to T4 in Fig. 14) in which the block ACK frame for the mobile station UE is transmitted.

14) of the A-MPDU (for example, A-MPDU # 3 in FIG. 14) in the third section (for example, T3 to T4 in FIG. 14) To the AP (e.g., 1400 in FIG. 14).

14) has elapsed after a certain time (for example, T4 to T6 in Fig. 14) has elapsed since the transmission of the block ACK frame for the A-MPDU (for example, A-MPDU # 3 in Fig. 14) Can be switched back to the dosing state.

The STA (e.g., 1430 in FIG. 14) may remain in the DOS state until the TXOP interval by the AP (e.g., 1400 in FIG. 14) ends at the end (e.g., T12 in FIG. 14).

According to this embodiment, the STA receiving the A-MDPU having the shortest data area can maintain the doze state for the longest time interval. According to the present embodiment, standby power consumption by the wireless terminal can be reduced. That is, an improved WLAN system from the viewpoint of power can be provided.

16 is a block diagram showing a wireless device to which this embodiment can be applied.

Referring to FIG. 16, a wireless device is an STA capable of implementing the above-described embodiment, and can operate as an AP or a non-AP STA. Further, the wireless device may correspond to the above-mentioned user or to a transmitting terminal that transmits a signal to the user.

16 includes a processor 1610, a memory 1620, and a transceiver 1630 as shown. The illustrated processor 1610, memory 1620 and transceiver 1630 may each be implemented as separate chips, or at least two blocks / functions may be implemented on a single chip.

A transceiver 1630 is a device that includes a transmitter and a receiver and is capable of either performing only the operation of either the transmitter or the receiver when a particular operation is performed, have.

Transceiver 1630 may include one or more antennas for transmitting and / or receiving wireless signals. The transceiver 1630 may also include an amplifier for amplifying the received signal and / or the transmitted signal and a bandpass filter for transmitting on a specific frequency band.

Processor 1610 may implement the functions, processes, and / or methods suggested herein. For example, the processor 1610 may perform the operations according to the embodiment described above. That is, processor 1610 may perform the operations described in the embodiments of FIGS. 1-15.

The processor 1610 may include an application-specific integrated circuit (ASIC), another chipset, logic circuitry, a data processing device, and / or a transducer for converting baseband signals and radio signals.

Memory 1620 may include read-only memory (ROM), random access memory (RAM), flash memory, memory cards, storage media, and / or other storage devices.

17 is a block diagram showing an example of a device included in the processor.

For convenience of explanation, the example of FIG. 17 is described with reference to a block for a transmission signal, but it is obvious that a received signal can be processed using the block.

The illustrated data processing unit 1110 generates transmission data (control data and / or user data) corresponding to a transmission signal. The output of the data processing unit 1710 may be input to the encoder 1720. The encoder 1720 can perform coding through BCC (binary convolutional code) or LDPC (low-density parity-check) techniques. At least one encoder 1120 may be included and the number of encoders 1720 may be determined according to various information (e.g., the number of data streams).

The output of the encoder 1720 may be input to an interleaver 1730. Interleaver 1730 performs operations to spread successive bit signals over radio resources (e.g., time and / or frequency) to prevent burst errors due to fading or the like. At least one interleaver 1730 may be included, and the number of interleavers 1730 may be determined according to various information (e.g., the number of spatial streams).

The output of the interleaver 1730 may be input to a constellation mapper 1740. The constellation mapper 1740 performs constellation mapping such as biphase shift keying (BPSK), quadrature phase shift keying (QPSK), and quadrature amplitude modulation (n-QAM).

The output of constellation mapper 1740 may be input to spatial stream encoder 1750. Spatial stream encoder 1750 performs data processing to transmit the transmitted signal on at least one spatial stream. For example, the spatial stream encoder 1750 can perform at least one of space-time block coding (STBC), cyclic shift diversity insertion (CSD), and spatial mapping for a transmission signal.

The output of the spatial stream encoder 1750 may be input to the IDFT 1760 block. The IDFT block 1760 performs inverse discrete Fourier transform (IDFT) or inverse fast Fourier transform (IFFT).

The output of the IDFT 1760 block is input to the GI (Guard Interval) inserter 1770 and the output of the GI inserter 1770 is input to the transceiver 1630 of FIG.

Although a detailed description of the present invention has been provided for specific embodiments, various modifications may be made without departing from the scope of the present invention. Therefore, the scope of the present specification should not be construed as being limited to the above-described embodiments, and should be defined by equivalents to the claims of the present invention as well as the following claims.

Claims (10)

1. A method for performing an operation according to a power save mode in a wireless LAN system,

   The first STA performs a reception operation on an EDMG MU PPDU, wherein the EDMG MU PPDU is received from an access point (AP), and the EDMG MU The PPDU includes a plurality of A-MPDUs (Aggregate MAC Protocol Data Units) having the same length to be transmitted on a preamble and an overlapped time resource, and each of the plurality of A-MPDUs includes a data area Wherein the preamble includes first order information on a transmission order of a first block ACK (block acknowledgment) frame for a first A-MPDU to be transmitted to the first STA among the plurality of A-MPDUs, Wherein the transmission order is determined according to a length of a data area included in the first A-MPDU;

   The first STA determining whether the transmission order of the first block ACK frame is first based on the first order information;

   When it is determined that the transmission order is not the first STA, the first STA determines the power state of the first STA at a first time point at which the reception of the first data area included in the first A- doze state;

   Wherein the first STA maintains the power state in the doze state from the first time point to the second time point, the second time point being obtained based on the first order information; And

   The first STA switching the power state from the doze state to an awake state when the second time point has elapsed.
2. The method according to claim 1,

   Wherein the preamble further comprises second order information for a transmission order of a second block ACK frame for a second A-MPDU to be transmitted to a second STA among a plurality of A-MPDUs.
3. The method according to claim 1,

   Wherein when the transmission order is first determined, the first STA transmits the power state to the awake state until the first STA transmits the first block ACK frame to the AP after the reception of the first A- ≪ / RTI >
4. The method of claim 3,

   Further comprising the step of the first STA transitioning the power state from the awake state to the doze state after a predetermined time has elapsed since transmission of the first block ACK frame.
5. The method according to claim 1,

   Wherein each of the plurality of A-MPDUs includes padding bits such that the plurality of A-MPDUs have the same length.
6. The method according to claim 1,

   Wherein when the length of the first A-MPDU is the longest among the plurality of A-MPDUs, the first block ACK frame of the plurality of block ACK frames corresponding to the plurality of A- A value is set indicating that it will be transmitted.
7. The method according to claim 1,

   When the length of the first A-MPDU is the second longest among the plurality of A-MPDUs, the first block ACK frame is transmitted a second time from a plurality of block ACK frames corresponding to the plurality of A-MPDUs How the value is set.
8. The method according to claim 1,

   The first STA receiving a Block Ack Request (BAR) frame requesting transmission of the first block ACK frame from the AP, the first STA being in the awake state; And

   The first STA sending the first block ACK frame to the AP in response to the BAR frame.
9. 9. The method of claim 8,

   Further comprising the step of the first STA switching the power state back from the awake state to the doze state after a certain time has elapsed since the transmission of the first block ACK frame.
10. A first wireless terminal for performing a method according to a power save mode in a wireless LAN system, the first wireless terminal comprising:

    A transceiver for transmitting and receiving a radio signal; And

    And a processor coupled to the transceiver,

    Wherein the EDMG MU PPDU is received from an access point (AP) and the EDMG MU PPDU is configured to perform a receive operation on an Enhanced Directional Multi-Gigabit Multi-User Physical Protocol Data Unit And a plurality of A-MPDUs (Aggregate MAC Protocol Data Units) having the same length transmitted on time resources, each of the plurality of A-MPDUs including a data area of a different length for each of a plurality of receivers, Comprises first order information on a transmission order of a first block ACK (block acknowledgment) frame for a first A-MPDU to be transmitted to the first STA among the plurality of A-MPDUs, 1 is determined according to the length of the data area included in the A-MPDU,

    And to determine whether the transmission order of the first block ACK frame is first based on the first order information,

    When it is determined that the transmission order is not the first, the power state of the first STA is switched to a doze state at a first time point at which the reception of the first data area included in the first A-MPDU is completed Implemented,

    And the power state is maintained in the dose state from the first time point to the second time point, the second time point is obtained based on the first order information,

    And to switch the power state from the doze state to an awake state when the second time point has elapsed.

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