WO2016088956A1 - Method and device for transmitting data unit - Google Patents

Abstract

Disclosed are a method and a device for transmitting a data unit. The method for transmitting a data unit in a wireless LAN may comprise the steps in which: an STA receives a trigger frame from an AP; and the STA transmits, on a subchannel, to the AP, a UL MU PPDU as a response to the trigger frame, wherein the UL MU PPDU may comprise a first field group which is transmitted by being encoded into units of a channel including the subchannel, and a second field group which is transmitted by being encoded into units of the subchannel.

Description

Method and device for transmission of data units

The present invention relates to wireless communications, and more particularly, to a method and apparatus for transmitting data units.

BACKGROUND With the proliferation of smart devices such as smart phones, tablets and smart home appliances, wireless communication based on wireless local area networks (WLANs) is increasing. In a WLAN network, communication may be performed based on a physical layer (PHY) protocol data unit (PPDU).

The PPDU may largely include a PHY preamble, a PHY header, and a data payload (or medium access control (MAC) payload). The term PPDU header may be used as a concept including a PHY preamble and a PHY header.

The PHY preamble may include a short training field (STF) and a long training field (LTF) for synchronization and channel estimation. The STF included in the PLCP preamble may be used for signal detection, automatic gain control (AGC), diversity selection, time synchronization, and frequency error estimation. LTF can be used for channel estimation and frequency error estimation.

The PHY header may include a rate field including information related to a transmission rate and a length field indicating the length of the PPDU.

The data payload (or data field) may include a PHY service data unit (PSU), a service, tail bits, and pad bits. Tail bits are used to bring the convolutional code to an initial state, and padding bits are bits added to make the total number of data bits an integer multiple of the coded bits of one orthogonal frequency division multiplexing (OFDM) symbol. All bits included in the data payload may be transmitted through scrambling, convolutional encoding, and interleaving.

An object of the present invention is to provide a method of transmitting data units.

Still another object of the present invention is to provide a transmission unit of data unit.

In accordance with an aspect of the present invention, there is provided a method of transmitting data units in a WLAN, in which a STA receives a trigger frame from an access point (AP) and the STA And transmitting an uplink multi-user PHY protocol data unit (UL MU PPDU) to the AP on a subchannel in response to the trigger frame, wherein the trigger frame includes UL MU identification information and UL MU resource allocation information. Wherein the UL MU identification information includes identification information of the STA and identification information of another STA transmitting another UL MU PPDU on a time resource overlapped with the STA, and the UL MU resource allocation information includes the subchannel And information on another subchannel for transmitting another UL MU PPDU, wherein the UL MU PPDU is encoded and transmitted in units of channels including the subchannel. 1 the group of fields and encoding in a unit of the sub-channels may comprise a second group of fields to be transmitted.

In the wireless LAN according to another aspect of the present invention for achieving the above object of the present invention, a station (station) for transmitting a data unit is implemented to transmit or receive a radio signal (RF) unit and the RF unit And a processor operatively coupled to the processor, the processor receiving a trigger frame from an access point and responsive to the trigger frame, an uplink multi user PHY protocol data unit. ) Is transmitted to the AP on a subchannel, and the trigger frame includes UL MU identification information and UL MU resource allocation information, wherein the UL MU identification information is overlapped with the identification information of the STA and the STA. Identification information of another STA for transmitting another UL MU PPDU on a resource, wherein the UL MU resource allocation information is for transmitting the subchannel and the other UL MU PPDU The UL MU PPDU includes information about another subchannel for the first field group encoded and transmitted in the unit of the channel including the subchannel and the second field group encoded and transmitted in the unit of the subchannel. It may include.

DL downlink multi-user (MU) orthogonal frequency division multiple access (OFDM) / DL multiple input multiple output (MIMO) and uplink multi-user (UL MU) OFDMA based on the newly defined PHY protocol data unit (PPDU) format A transmission and reception procedure of data based on / UL MU MIMO may be performed. Therefore, the utilization efficiency of radio resources in the WLAN system may increase.

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

2 is a conceptual diagram illustrating an A-MSDU.

3 is a conceptual diagram illustrating an A-MPDU.

4 is a conceptual diagram illustrating DL MU transmission according to an embodiment of the present invention.

5 is a conceptual diagram illustrating a DL MU PPDU according to an embodiment of the present invention.

6 is a conceptual diagram illustrating a DL MU PPDU according to an embodiment of the present invention.

7 is a conceptual diagram illustrating UL MU transmission according to an embodiment of the present invention.

8 illustrates a UL MU PPDU according to an embodiment of the present invention.

9 is a conceptual diagram illustrating a UL MU PPDU transmitted by a UL MU target STA according to an embodiment of the present invention.

10 is a conceptual diagram illustrating a UL MU PPDU transmitted by a UL MU target STA according to an embodiment of the present invention.

11 is a conceptual diagram illustrating a UL MU PPDU transmitted by a UL MU target STA according to an embodiment of the present invention.

12 is a conceptual diagram illustrating a HE-SIG2 field according to an embodiment of the present invention.

13 is a block diagram illustrating a wireless device to which an embodiment of the present invention can be applied.

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

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

Referring to the top of FIG. 1, the WLAN system may include one or more infrastructure BSSs 100 and 105 (hereinafter, BSS). The BSSs 100 and 105 are a set of APs and STAs such as an access point 125 and a STA1 (station 100-1) capable of successfully synchronizing and communicating with each other, and do not indicate a specific area. The BSS 105 may include one or more joinable STAs 105-1 and 105-2 to one AP 130.

The BSS may include at least one STA, APs 125 and 130 for providing a distribution service, and a distribution system (DS) 110 for connecting a plurality of APs.

The distributed system 110 may connect several BSSs 100 and 105 to implement an extended service set (ESS) 140 which is an extended service set. The ESS 140 may be used as a term indicating one network in which one or several APs 125 and 230 are connected through the distributed system 110. APs included in one ESS 140 may have the same service set identification (SSID).

The portal 120 may serve as a bridge for connecting the WLAN network (IEEE 802.11) with another network (for example, 802.X).

In the BSS as shown in the upper part of FIG. 1, a network between the APs 125 and 130 and a network between the APs 125 and 130 and the STAs 100-1, 105-1 and 105-2 may be implemented. However, it may be possible to perform communication by setting up a network even between STAs without the APs 125 and 130. A network that performs communication by establishing a network even between STAs without APs 125 and 130 is defined as an ad-hoc network or an independent basic service set (BSS).

1 is a conceptual diagram illustrating an IBSS.

Referring to the bottom of FIG. 1, the IBSS is a BSS operating in an ad-hoc mode. Since IBSS does not contain an AP, there is no centralized management entity. That is, in the IBSS, the STAs 150-1, 150-2, 150-3, 155-4, and 155-5 are managed in a distributed manner. In the IBSS, all STAs 150-1, 150-2, 150-3, 155-4, and 155-5 may be mobile STAs, and access to a distributed system is not allowed, thus making a self-contained network. network).

A STA is any functional medium that includes medium access control (MAC) conforming to the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard and a physical layer interface to a wireless medium. May be used to mean both an AP and a non-AP STA (Non-AP Station).

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

An access point (AP) operating in a wireless local area network (WLAN) system may transmit data through the same time resource to each of a plurality of stations (STAs). If the transmission from the AP to the STA is called downlink transmission, the transmission to each of the plurality of STAs of the AP may be expressed in terms of downlink multi-user transmission (or downlink multi-user transmission).

2 is a conceptual diagram illustrating an A-MSDU.

In order to reduce medium access control (MAC) error overhead in a WLAN system, a method of aggregating data frames has been defined. The MAC service data unit (MSDU) 200 generated in the application layer for aggregation of data frames may be aggregated in an upper layer of the MAC layer and generated as one data unit. The MSDU aggregated in the upper layer of the MAC layer may be defined in the term A-MSDU (aggregate-MSDU) 250. The A-MSDU 250 may be generated based on aggregation of a plurality of MSDUs 200 having the same priority and having the same receiver address (RA).

A plurality of A-MSDU subframes may be gathered to form one A-MSDU 250. That is, the A-MSDU 250 may include a plurality of A-MSDU subframes, and the A-MSDU subframe may include a subframe header, an MSDU, and a padding bit. The subframe header may include a destination address (DA), a source address (SA), and an MSDU length. The patting bits can be used to make the entire length of the A-MSDU subframe a constant multiple (multiple of 4 octets).

The A-MSDU 250 may be formed and transmitted as a single QoS data MAC protocol data unit (MPDU) without being fragmented differently from a single MSDU. For example, the A-MSDU 250 may be transmitted by a high throughput (HT) STA in a management information base (MIB) field. In the case of the HT STA, the A-MSDU 250 has the capability of de-aggregating the HT STA, and the HT STA checks whether the A-MSDU 250 exists in the QoS field of the MAC header of the received PPDU. And de-aggregate the A-MSDU 250.

When the ACK policy of the HT STA is set to normal ACK, the A-MSDU 250 may not be aggregated into a MAC protocol data unit (A-MPDU). In addition, whether the A-MSDU 200 can be aggregated into the A-MPDU may vary depending on whether a block acknowledgment agreement for each traffic identifier (TID) is made. Also, even when a block ACK agreement is made for the TID, the A-MSDU block ACK support indicator of the ADDBA acknowledgment response frame according to the ADDBA request frame adds a block ACK. If not indicated, A-MSDU 250 may not be included in the A-MPDU.

3 is a conceptual diagram illustrating an A-MPDU.

Referring to FIG. 3, one A-MPDU 350 may be formed by collecting a plurality of MPDUs 300 having the same receiver address (RA), a TID, and an ACK policy under the MAC layer.

The A-MPDU 350 is composed of one or more A-MPDU subframes, and each A-MPDU subframe may include an MPDU delimiter and an MPDU 300. The MPDU delimiter may be used to determine whether an A-MPDU subframe constituting the A-MPDU 350 is in error. The plurality of A-MPDU subframes may form one A-MPDU 350.

Successful reception of the A-MPDU 350 may be indicated based on the block ACK. The A-MPDU 350 may be formed only for the TID having the HT-immediate BA agreement, and the duration / ID field of the MPDU 300 constituting the A-MPDU 350 may be configured. The value can be set equally.

The A-MPDU (or MPDU) may be included in a physical layer (PHY) service data unit (PSU). The PSDU and the PPDU header (PHY preamble and PHY header) may form a PHY protocol data unit (PPDU).

The AP operating in the WLAN system may transmit data through the overlapped time resources to each of the plurality of STAs. If the transmission from the AP to the STA is called downlink transmission, the transmission of such an AP may be expressed in terms of DL MU transmission (or downlink multi-user transmission). In contrast, DL single user (SU) transmission may indicate downlink transmission from the AP to one STA on the entire transmission resource.

In the existing WLAN system, the AP may perform DL MU transmission based on MU multiple input multiple output (MUMI), and this transmission may be expressed by the term DL MU MIMO transmission. In an embodiment of the present invention, the AP may perform DL MU transmission based on orthogonal frequency division multiple access (OFDMA), and this transmission may be expressed by the term DL MU OFDMA transmission. When DL MU OFDMA transmission is performed, the AP may transmit downlink data (or downlink frame, downlink PPDU) to each of the plurality of STAs through the plurality of frequency resources on the overlapped time resources. DL MU OFDMA transmission can be used with DL MU MIMO transmission. For example, DL MU-MIMO transmission based on a plurality of space-time streams (or spatial streams) on a specific subband (or subchannel) allocated for DL MU OFDMA transmission may be performed. Can be performed.

Each of the PPDUs, frames, and data transmitted based on the downlink transmission may be expressed by the terms downlink PPDU, downlink frame, and downlink data. The PPDU may be a data unit including a PPDU header and a physical layer service data unit (PSDU) (or MAC protocol data unit (MPDU), or MAC payload). The PPDU header may include a PHY header and a PHY preamble. The PSDU (or MPDU) may be a data unit or frame including a frame.

In contrast, transmission from an STA to an AP may be referred to as an uplink transmission, and transmission of data from a plurality of STAs to an AP on the same time resource is called UL MU transmission (or uplink multi-user transmission). Can be expressed in terms. The UL SU transmission may indicate uplink transmission from one STA to one AP on all transmission resources. Unlike conventional WLAN systems that allow only UL SU transmission, the UL MU transmission may also be supported in the WLAN system according to an embodiment of the present invention. Each of the PPDUs, frames, and data transmitted through the uplink may be represented by the term uplink PPDU, uplink frame, and uplink data. Uplink transmission by each of the plurality of STAs may be performed in a frequency domain or a spatial domain.

When uplink transmission by each of the plurality of STAs is performed in the frequency domain, different frequency resources may be allocated as uplink transmission resources for each of the plurality of STAs based on OFDMA. Each of the plurality of STAs may transmit uplink data to the AP through different allocated frequency resources. The transmission method through these different frequency resources may be represented by the term UL MU OFDMA transmission method.

When uplink transmission by each of the plurality of STAs is performed in the spatial domain, different space-time streams (or spatial streams) are allocated to each of the plurality of STAs, and each of the plurality of STAs transmits uplink data through different space-time streams. Can transmit to the AP. The transmission method through these different spatial streams may be represented by the term UL MU MIMO transmission method.

The UL MU OFDMA transmission and the UL MU MIMO transmission may be performed together. For example, UL MU MIMO transmission based on a plurality of space-time streams (or spatial streams) may be performed on a specific subband (or subchannel) allocated for UL MU OFDMA transmission.

Hereinafter, in an embodiment of the present invention, a PPDU format for DL MU transmission and UL MU transmission in a WLAN system is disclosed. In the following description, a subchannel is disclosed as a minimum frequency resource unit for DL MU OFDMA transmission. That is, the total frequency resource may include a plurality of subchannels. The term “subband,” not subchannel, may be used as a term indicating a minimum frequency resource unit for DL MU OFDMA transmission included in all frequency resources. In another representation, the total frequency resource may include a plurality of channels (eg, primary channel, secondary channel), and each of the plurality of channels may include a plurality of subchannels.

Specifically, in the embodiment of the present invention, a method of transmitting a DL MU PPDU and a UL MU PPDU through each of four subchannels (subchannel 1, subchannel 2, subchannel 3, and subchannel 4) is disclosed. Four subchannels are one example of a plurality of subchannels. Other numbers of subchannels may be used for DL MU OFDMA transmission and UL MU OFDMA transmission. In addition, hereinafter, in the embodiment of the present invention, it is assumed that the total bandwidth of 40MH size, two 20MHz size channels included in the total bandwidth of 40MHz, and two 10MHz size subchannels included in the 20MHz size channel. However, the size of the entire band, the size of the channel, the size of the sub-channel may vary.

4 is a conceptual diagram illustrating DL MU transmission according to an embodiment of the present invention.

Referring to FIG. 4, the AP 400 may transmit a DL MU PPDU to a plurality of STAs based on DL MU OFDMA transmission. The DL MU PPDU may be a data unit for transmission of downlink data for each of the plurality of STAs on the overlapped time resource.

The DL MU PPDU may include a PPDU header and a MAC payload, and the PPDU header may include a legacy PPDU header and a high efficiency (HE) PPDU header. The MAC payload may be expressed as a frame, PSDU, or MPDU in another representation.

The legacy PPDU header may include a legacy short training field (L-STF), a legacy long training field (L-LTF), and a legacy signal field (L-SIG).

The HE PPDU header includes a plurality of signal fields (eg, HE-SIG1 (or HE-SIG A), HE-SIG2 (or HE-SIG B) and HE-SIG3 (or HE-SIG C)) and HE-training. Fields HE-STF and HE-LTF may be included.

Some signal fields (eg, HE-SIG 1) included in the HE PPDU header of the DL MU PPDU may be transmitted in a duplicated format duplicated on a channel basis. In addition, some of the signal fields included in the HE PPDU header may include the entire band (subchannel 1, subchannel 2, subchannel 3 and subchannel 4) or individual subchannels (subchannel 1, subchannel 2, subchannel 3 and sub). And encoded on channel 4).

Each of the STA1 410, the STA2 420, the STA3 430, and the STA4 440 that has received the DL MU PPDU decodes the HE PPDU header to determine the STA1 410, STA2 420, STA3 430, and STA4 ( 440 may acquire information on the subchannels allocated to each. Each of the STA1 410, the STA2 420, the STA3 430, and the STA4 440 is transmitted through a subchannel allocated to each of the STA1 410, the STA2 420, the STA3 430, and the STA4 440. The MAC payload may be decoded to receive downlink data for each of the STA1 410, the STA2 420, the STA3 430, and the STA4 440.

When DL MU OFDMA transmission as well as DL MU OFDMA transmission is used for DL MU transmission, a plurality of STAs (eg, through a plurality of space-time streams on a specific subchannel (eg, on subchannel 1) may be used. Downlink data for each of the STA1 410, the STA5, the STA6, and the STA7 may be transmitted. Hereinafter, for convenience of description, a DL MU PPDU format for DL MU OFDMA transmission is disclosed. However, when DL MU MIMO is used, a downlink PPDU including a PPDU header and a MAC payload is provided through a plurality of space-time streams on a specific subchannel. Can be sent.

Each of the STA1 410, the STA2 420, the STA3 430, and / or the STA4 440 successfully transmits an UL ACK frame (or a block acknowledgment (BA) frame) when the decoding of the DL MU PPDU is successful. It may transmit to the AP 400 based on the MU transmission.

Hereinafter, in the embodiment of the present invention, the format (or structure) of a specific DL MU PPDU is disclosed. In the DL MU PPDU, HE-SIG1 is an HE-SIG1 field (or HE-SIG A field), HE-SIG2 is an HE-SIG2 field (or HE-SIG B field), and HE-SIG3 is an HE-SIG3 field (or HE-SIG C field).

5 is a conceptual diagram illustrating a DL MU PPDU according to an embodiment of the present invention.

In FIG. 5, a DL MU PPDU including HE-SIG2 encoded over the entire band is disclosed.

Referring to FIG. 5, the DL MU PPDU may include a legacy PPDU header, a HE PPDU header, and a MAC payload.

The legacy PPDU header may include L-STF, L-LTF and L-SIG.

The L-STF 500 may include a short training orthogonal frequency division multiplexing symbol. The L-STF 500 may be used for frame detection, automatic gain control (AGC), diversity detection, and coarse frequency / time synchronization.

The L-LTF 510 may include a long training orthogonal frequency division multiplexing symbol. The L-LTF 510 may be used for fine frequency / time synchronization and channel prediction.

L-SIG 520 may be used to transmit control information. The L-SIG 520 may include information about a data rate and a data length.

The HE PPDU header may include an HE-SIG1 530, an HE-SIG2 540, an HE-STF 550, an HE-LTF 560, and an HE-SIG3 570.

The HE-SIG1 530 may include common information (BW (bandwidth), guard interval (GI) length, BSS index, cyclic redundancy check, tail bit, etc.) for decoding the DL MU PPDU. Can be.

Specifically, the HE-SIG1 530 is a color bit for BSS identification, a bit indicating the total bandwidth size in which the DL MU PPDU is transmitted, a tail bit, a CRC bit, and a cyclic prefix (CP). (Or guard interval (GI)) may include a bit indicating the length. The bit indicating the total bandwidth size in which the DL MU PPDU is transmitted may indicate a continuous frequency resource or a discontinuous frequency resource for transmission of the DL MU PPDU.

In addition, the HE-SIG1 530 may further include information related to the HE-SIG2 540. For example, the HE-SIG1 530 further includes information on the modulation and coding scheme (MCS) applied to the HE-SIG2 540 and information about the number of OFDM symbols allocated for the HE-SIG2 540. can do.

In addition, the HE-SIG1 530 may also include information about the space-time stream. For example, the information about the space-time stream may include information about the number of space-time streams used for transmission of the MAC payload in each of a plurality of subchannels through which the DL MU PPDU is transmitted.

In addition, the HE-SIG1 530 may also include information on beamforming of the space-time stream and information related to clear channel assessment and power control of the STA.

The HE-SIG2 540 may include information about each of the plurality of STAs that will receive the DL MU PPDU. For example, the HE-SIG2 540 may include identification information (eg, a partial association identifier (PAID) and a group identifier (GID)) of a plurality of STAs to receive the DL MU PPDU.

In addition, the HE-SIG2 540 may include information on resources allocated to each of the plurality of STAs to receive the DL MU PPDU. In more detail, the HE-SIG2 540 may include OFDMA-based resource allocation information (or MU-MIMO information) for each of the plurality of STAs that will receive the DL MU PPDU. For example, the HE-SIG2 540 is a field after the HE-SIG2 540 transmitted to each of the plurality of STAs (eg, the HE-STF 550, the HE-LTF 560, and the HE-SIG3 570). And MAC payload 580) may be included.

The HE-STF 550 may be used to improve automatic gain control estimation in a multiple input multiple output (MIMO) environment or an OFDMA environment. In more detail, the HE-STF 550 may be used for automatic gain control estimation and channel estimation for decoding of a field after being transmitted in the same subchannel to which the HE-STF 550 is transmitted.

The HE-LTF 560 may be used to estimate a channel in a MIMO environment or an OFDMA environment. In more detail, the HE-LTF 560 may be used for channel estimation for decoding of a field after being transmitted in the same subchannel to which the HE-LTF 560 is transmitted.

The HE-SIG3 570 may include information for decoding the MAC payload. Information for decoding the MAC payload may include MCS, Coding, space time block coding (STBC), transmit beamforming (TXBF), and the like. In more detail, the HE-SIG3 570 includes information on an MCS applied to a MAC payload transmitted in the same subchannel as the subchannel to which the HE-SIG3 570 is transmitted, and STBC and TXBF used for transmission of the MAC payload. Information may be included. Information included in the HE-SIG3 570 may be included in the HE-SIG2 540, and in this case, the HE-SIG3 570 may not be included as a separate field in the DL MU PPDU.

Each of the plurality of MAC payloads included in the DL MU PPDU may include downlink data to be transmitted to the STA. The MAC payload may include a MAC header and an MSDU (or MAC body). The MAC header receives a duration / ID field including information on time resources for the transmission procedure of the DL MU PPDU, an identifier of the transmitting STA that transmitted the MAC payload (or frame), and a MAC payload (or frame). It may include an identifier of the STA. The MSDU may include downlink data to be transmitted to the STA held in the AP.

According to an embodiment of the present invention, in the DL MU PPDU, the L-STF 500, the L-LTF 510, the L-SIG 520, and the HE-SIG1 530 may be provided in a plurality of sub-channel units (or channel units). Can be encoded. The HE-SIG1 530 encoded in a plurality of sub-channel units (or channel units) may be transmitted in a duplicate format over the entire bandwidth. At least one field of the L-STF 500, the L-LTF 510, and the L-SIG 520 may also be transmitted in a duplicate format over the entire bandwidth.

The duplicate format may be generated based on replication and duplication of fields transmitted on a specific band. When the duplicate format is used, fields of a specific band may be replicated or duplicated so that the duplicated fields may be transmitted on a plurality of bands.

The L-STF 500, the L-LTF 510, the L-SIG 520, and the HE-SIG1 530 may include a first channel including subchannel 1 and subchannel 2, and subchannel 3 and subchannel 4. It may be encoded on the second channel including.

The L-STF 500, the L-LTF 510, and the L-SIG 520 may be encoded on each of the first channel and the second channel, and transmitted through the first channel and the second channel. The HE-SIG1 530 encoded on the first channel may be duplicated and transmitted on a second channel including subchannel 3 and subchannel 4 as well as the first channel. That is, the HE-SIG1 530 may be transmitted based on a duplicate format in each of the first channel and the second channel. As a duplicate format, the HE-SIG1 530 transmitted on the first channel and the HE-SIG1 530 transmitted on the second channel may include the same data.

The HE-SIG2 540 may be encoded and transmitted on the entire band allocated to the DL MU PPDU. For example, the HE-SIG2 540 may be encoded and transmitted in a 40 MHz band allocated to a DL MU PPDU.

The HE-STF 550, the HE-LTF 560, and the HE-SIG3 570 are encoded and transmitted on frequency resources (subchannels) allocated to each of a plurality of STAs receiving downlink data through a DL MU PPDU. Can be. For example, it may be assumed that each of subchannel 1, subchannel 2, subchannel 3, and subchannel 4 is allocated to each of STA1, STA2, STA3, and STA4. In this case, the HE-STF 550, HE-LTF 560, and HE-SIG3 570 are encoded in subchannel 1, subchannel 2, subchannel 3, and subchannel 4, respectively, to be STA1, STA2, STA3, and STA4. May be sent to each. The HE-STF 550, the HE-LTF 560, and the HE-SIG3 570 transmitted on the subchannel 1, the subchannel 2, the subchannel 3, and the subchannel 4 respectively are STA1, STA2, STA3, and STA4, respectively. Individual training field information and control information for decoding of the MAC payload 580 may be included.

In FIG. 5, for convenience of description, it is assumed that each of subchannel 1, subchannel 2, subchannel 3, and subchannel 4 is allocated to each of STA1, STA2, STA3, and STA4, but various other resource allocations are possible. For example, subchannel 1 and subchannel 2 may be allocated to STA1, and subchannel 3 and subchannel 4 may be allocated to STA2. Alternatively, subchannel 1 and subchannel 2 may be allocated to STA1, subchannel 3 to STA2, and subchannel 4 to STA3. Alternatively, discontinuous subchannels may be allocated to one STA in the frequency domain.

Each of the STA1, the STA2, the STA3, and the STA4 may perform the following operation. For example, STA1, STA2, STA3, and STA4 receive the L-STF 500, L-LTF 510, L-SIG 520, and HE-SIG 530 through the first channel or the second channel. can do. L-STF 500 and L-LTF 510 may be used for decoding of L-SIG 520 and HE-SIG1 530 and HE-SIG2 540. STA1, STA2, STA3, and STA4 acquire information about the total bandwidth (eg, 40 MHz) to which the HE-SIG2 540 is transmitted based on the bandwidth information included in the HE-SIG1 530 and transmit on the entire bandwidth. The decoding of the HE-SIG2 540 may be performed. Each of STA1, STA2, STA3, and STA4 obtains information about resources (eg, subchannels) allocated to each of STA1, STA2, STA3, and STA4 included in the HE-SIG2 540, and transmits the information on the allocated subchannels. The HE-STF 550, the HE-LTF 560, the HE-SIG3 570, and the MAC payload 580 may be received.

The HE-STF 550, HE-LTF 560 may be used for channel estimation for decoding of the HE-SIG3 570 and the MAC payload 580. Each of STA1, STA2, STA3, and STA4 performs decoding on the MAC payload 580 transmitted on the allocated subchannels based on the HE-STF 550, the HE-LTF 560, and the HE-SIG3 570. can do.

6 is a conceptual diagram illustrating a DL MU PPDU according to an embodiment of the present invention.

In FIG. 6, a DL MU PPDU including HE- SIG2 640 and 645 encoded in a plurality of subchannel units (or channel units) on the entire band allocated to the DL MU PPDU is disclosed.

Information included in the previous fields (L-STF 600, L-LTF 610, L-SIG 620, and HE-SIG1 630), HE-SIG2 640 The purpose of the previous field and the encoding / decoding method may be the same as described above in FIG. 5. In addition, information included in the fields after the HE-SIG2 640 and 645 (HE-STF 650, HE-LTF 660, HE-SIG3 670, and MAC payload 680), HE-SIG2 ( 640 and 645) and the purpose of the field and the encoding / decoding method may be the same as described above in FIG.

Referring to FIG. 6, the HE- SIG2 640 and 645 may be encoded and transmitted in channel units (the first channel and the second channel, respectively).

The first HE-SIG2 640 transmitted through the first channel and the second HE-SIG2 645 transmitted through the second channel are duplicated in channel units to be transmitted in a duplicated format. Can be. That is, the first HE-SIG2 640 transmitted through the first channel and the second HE-SIG2 645 transmitted through the second channel may include the same information.

In this case, each of the first HE-SIG2 640 and the second HE-SIG2 645 may include control information related to the overall bandwidth. For example, each of the first HE-SIG2 640 and the second HE-SIG2 645 may include information about each of the plurality of STAs that will receive the DL MU PPDU. In addition, each of the first HE-SIG2 640 and the second HE-SIG2 645 may include information on resources allocated to each of the plurality of STAs to receive the DL MU PPDU.

Each of the first HE-SIG2 640 transmitted through the first channel and the second HE-SIG2 645 transmitted through the second channel are transmitted in a non-duplicated format and the first HE-SIG2 645. Each of the SIG2 640 and the second HE-SIG2 645 may include different data. For example, the first HE-SIG2 640 may include information about a first STA group that receives a DL MU PPDU on a first channel among a plurality of STAs that receive a DL MU PPDU. In more detail, the first HE-SIG2 640 may include identification information of the STA included in the first STA group and resource allocation information about the STA included in the first STA group. In addition, the second HE-SIG2 645 may include information about a second STA group that receives the DL MU PPDU on the second channel among the plurality of STAs that receive the DL MU PPDU. In more detail, the second HE-SIG2 645 may include identification information of the STA included in the second STA group and resource allocation information about the STA included in the second STA group.

When each of the first HE-SIG2 640 transmitted through the first channel and the second HE-SIG2 645 transmitted through the second channel is transmitted in a non-duplicate format, the HE-SIG1 630 may be provided in plural. Each of the STAs may include information (receive HE-SIG2 indication information) indicating HE- SIG2 640 and 645 to be received. For example, the HE-SIG1 630 may include information on transmission bands of the HE- SIG2 640 and 645 for each of the plurality of STAs.

Assuming that each of subchannel 1, subchannel 2, subchannel 3, and subchannel 4 is allocated to each of STA1, STA2, STA3, and STA4, each of STA1, STA2, STA3, and STA4 may perform the following operations. . For example, each of STA1, STA2, STA3, and STA4 is an L-STF 600, L-LTF 610, L-SIG 620, HE-SIG1 630 through a first channel and / or a second channel. ) Can be received.

DL MU PPDU reception operations of STA1, STA2, STA3, and STA4 may vary depending on whether the first HE-SIG2 640 and the second HE-SIG2 645 are in a duplicate format or a non-duplicate format.

When the first HE-SIG2 640 and the second HE-SIG2 645 are transmitted in a duplicate format, each of the STA1, STA2, STA3, and STA4 is an L-STF 600, an L-LTF 610, or an L-LTF 610. The HE- SIG2 640 and 645 may be received through a channel that receives the SIG 620 and the HE-SIG1 630. For example, when the STA1 receives the L-STF 600, the L-LTF 610, the L-SIG 620, and the HE-SIG1 630 through the first channel, the STA1 receives the first channel. The first HE-SIG2 640 transmitted may be received and decoded. Each of STA1, STA2, STA3, and STA4 obtains information about resources (eg, subchannels) allocated to each of STA1, STA2, STA3, and STA4 included in the HE- SIG2 640 and 645, and allocates the allocated subchannels. The HE-STF 650, the HE-LTF 660, the HE-SIG3 670, and the MAC payload 680 transmitted on the mobile station may be received.

When the first HE-SIG2 640 and the second HE-SIG2 645 are transmitted in a non-duplicate format, each of the STA1, STA2, STA3, and STA4 is a received HE-SIG2 indication included in the HE-SIG1 630. The first HE-SIG2 640 or the second HE-SIG2 645 may be received based on the information. It is assumed that the first HE-SIG2 640 is allocated to STA1 and STA2, and the second HE-SIG2 645 is allocated to STA3 and STA4.

STA1 and STA2 may receive a first HE-SIG2 640 transmitted through a first channel, and STA3 and STA4 may receive a second HE-SIG2 645 transmitted through a second channel. STA1 transmits the HE-STF 650, HE-LTF 660, HE-SIG3 670, and MAC payload transmitted on subchannel 1 based on the resource allocation information included in the first HE-SIG2 640. 680, and the STA2 may receive the HE-STF 650, the HE-LTF 660, and the HE-SIG3 transmitted on the subchannel 2 based on the resource allocation information included in the first HE-SIG2 640. 670 and the MAC payload 680 may be received. In addition, STA3 is based on the resource allocation information included in the second HE-SIG2 (645) HE-STF 650, HE-LTF (660), HE-SIG3 (670) and MAC pay transmitted on subchannel 3 The load 680 may be received, and the STA4 may transmit the HE-STF 650, the HE-LTF 660, and the HE transmitted on the subchannel 4 based on the resource allocation information included in the second HE-SIG2 645. Receive the SIG3 670 and the MAC payload 680.

7 is a conceptual diagram illustrating UL MU transmission according to an embodiment of the present invention.

Referring to FIG. 7, uplink transmission of a plurality of STAs is initiated.

The AP may transmit a trigger frame 700 to the plurality of STAs to induce uplink transmission of the plurality of STAs.

A transmission opportunity (TXOP) duration, which is a time resource for the UL MU transmission procedure, may be obtained based on the transmission of the trigger frame 700 of the AP.

The trigger frame 700 may include information for transmission of the UL MU PPDU 720 of each of the plurality of STAs. A plurality of STAs to which the transmission of the UL MU PPDU 720 is induced based on the trigger frame 700 may be represented by the term UL MU target STA.

For example, the trigger frame 700 may include resource allocation information for each of the plurality of UL MU target STAs, identification information for each of the plurality of UL MU target STAs, and a UL MU PPDU 720 transmitted by each of the plurality of UL MU target STAs. ) May include information about MCS applied to the MCS, information about the MU type of the UL MU PPDU 720 transmitted by each of the plurality of UL MU target STAs (OFDMA, MIMO), and the like.

In addition, the trigger frame 700 may further include information on the transmission power of the UL MU PPDU 720, space time block coding (STBC) to be used for transmission of the UL MU PPDU 720, and information on beamforming. .

Each of the plurality of UL MU target STAs receiving the trigger frame 700 may transmit the UL MU PPDU 720 to the AP based on a short interframe space (SIFS). For example, each of the plurality of UL MU target STAs that receive the trigger frame 700 may receive the trigger frame 700 and transmit the UL MU PPDU 720 to the AP after SIFS.

The AP may transmit a block ACK frame 740 for the UL MU PPDU 720 received from the plurality of UL MU target STAs to the plurality of UL MU target STAs.

That is, the STA may include receiving a trigger frame from the AP, and the STA transmits a UL MU PPDU to the AP on the subchannel in response to the trigger frame.

The trigger frame may include UL MU identification information and UL MU resource allocation information, and the UL MU identification information may include identification information of the STA and identification information of another STA transmitting another UL MU PPDU on a time resource overlapped with the STA. have.

The UL MU resource allocation information includes information on subchannels and other subchannels for transmitting other UL MU PPDUs, and the UL MU PPDUs are encoded and transmitted in units of channels including subchannels and transmitted. The second field group may be encoded and transmitted in units of channels.

Hereinafter, in the embodiment of the present invention, a format (or structure) of a specific UL MU PPDU 720 is disclosed.

8 illustrates a UL MU PPDU according to an embodiment of the present invention.

In FIG. 8, a UL MU PPDU format transmitted by a plurality of UL MU target STAs on an entire band allocated to a plurality of UL MU target STAs is disclosed. The UL MU PPDU disclosed in FIG. 8 is disclosed in terms of an AP. That is, the UL MU PPDU disclosed in FIG. 8 may include each of a plurality of UL MU PPDUs transmitted by each of a plurality of UL MU target STAs.

Referring to FIG. 8, the UL MU PPDU may include a PPDU header (legacy PPDU header, HE PPDU header) and a MAC payload.

The legacy PPDU header may include an L-STF 800, an L-LTF 810, and an L-SIG 820.

Each of the L-STF 800, the L-LTF 810, and the L-SIG 820 of the UL MU PPDU may play the same role as each of the L-STF, L-LTF, and L-SIG of the DL MU PPDU. . For example, L-STF 800 and L-LTF 810 may then be used for channel prediction for decoding of the transmitted field. The L-SIG 820 may include control information such as information about a data rate and data length.

The HE PPDU header may include a HE-SIG1 830, a HE-STF 840, a HE-LTF 850, and a HE-SIG3 860.

The HE-SIG1 830 may include common information (BW, GI length, BSS index, cyclic redundancy check, tail bit, etc.) for decoding the UL MU PPDU. Specifically, the HE-SIG1 830 may include a color bit for BSS identification, a bit indicating a total bandwidth size in which the UL MU PPDU is transmitted, a tail bit, a CRC bit, and a bit indicating a CP (or GI) length. Can be. Some information included in the HE-SIG1 830 may be determined based on control information for UL MU transmission included in the trigger frame.

The L-STF 800, the L-LTF 810, the L-SIG 820, and the HE-SIG1 830 may be encoded and transmitted in units of channels.

According to an embodiment of the present invention, the UL MU PPDU may not include HE-SIG2. Information indicating each of the plurality of UL MU target STAs and resource allocation information for each of the plurality of UL MU target STAs may be transmitted through a trigger frame transmitted by the AP. Information indicating each of the plurality of UL MU target STAs and resource allocation information for each of the plurality of UL MU target STAs are information determined by the AP. Accordingly, the AP may not receive information indicating each of the plurality of UL MU target STAs and resource allocation information for each of the plurality of UL MU target STAs through the HE-SIG2. Thus, the UL MU PPDU may not include HE-SIG2.

In the UL MU PPDU, the HE-STF 840, the HE-LTF 850, and the HE-SIG3 860 and the MAC payload 870 may be encoded and transmitted on each of a plurality of subchannels.

Each of the HE-STF 840 and the HE-LTF 850 of the UL MU PPDU may play the same role as each of the HE-STF and the HE-LTF of the DL MU PPDU. For example, the HE-STF 840 and the HE-LTF 850 are channels for decoding a field after being transmitted on the same subchannel as the HE-STF 840 and the HE-LTF 850 are transmitted. Can be used for prediction.

The HE-SIG3 860 may include information for decoding the MAC payload 870. Information for decoding the MAC payload 870 may include MCS, Coding, STBC, TXBF, and the like. In more detail, the HE-SIG3 860 transmitted through each of the plurality of subchannels is used to transmit information about the MCS applied to the MAC payload 870 transmitted through each of the plurality of subchannels and the MAC payload 870. It may include information on the used STBC, TXBF.

In FIG. 8, a UL MU PPDU including the HE-SIG3 860 is assumed, but information (MCS, Coding, STBC, TXBF, etc.) included in the HE-SIG3 860 is determined by the AP and transmitted through a trigger frame. The same information may be the same. Thus, the HE-SIG3 860 may not be included in the UL MU PPDU.

The MAC payload 870 may include uplink data of the UL MU target STA triggered by the AP.

AP transmits UL channel by assigning each of subchannel 1, subchannel 2, subchannel 3 and subchannel 4 to UL MU target STA1, UL MU target STA2, UL MU target STA3, and UL MU target STA4 based on the trigger frame It can be assumed that the trigger.

The AP may receive the L-STF 800, the L-LTF 810, the L-SIG 820, and the HE-SIG1 830 transmitted through the first channel and the second channel, respectively. In addition, the AP transmits the HE-STF 840, the HE-LTF 850, and the HE- that are transmitted by the STA1, the STA2, the STA3, and the STA4 through the subchannel 1, the subchannel 2, the subchannel 3, and the subchannel 4, respectively. SIG3 860 and MAC payload 870 may be received.

9 is a conceptual diagram illustrating a UL MU PPDU transmitted by a UL MU target STA according to an embodiment of the present invention.

In FIG. 9, a UL MU PPDU transmitted by one UL MU target STA among a plurality of UL MU target STAs is disclosed. The UL MU PPDU disclosed in FIG. 9 is disclosed in view of a STA. That is, the UL MU PPDU disclosed in FIG. 9 may be a UL MU PPDU transmitted by one UL MU target STA.

In FIG. 9, the AP allocates each of subchannel 1, subchannel 2, subchannel 3, and subchannel 4 to UL MU target STA1, UL MU target STA2, UL MU target STA3, and UL MU target STA4 based on the trigger frame. It may be assumed that triggering uplink transmission.

Referring to FIG. 9, the UL MU target STA1 may transmit the UL MU PPDU1 in response to a trigger frame. The UL MU PPDU1 is transmitted on the L-STF 900, the L-LTF 910, the L-SIG 920, and the HE-SIG1 930 transmitted on the first channel and the subchannel 1 included in the first channel. HE-STF 940, HE-LTF 950, HE-SIG3 960, and MAC payload 970.

In the same manner, the UL MU target STA2 may transmit the UL MU PPDU2 in response to the trigger frame. The UL MU PPDU2 includes the L-STF, L-LTF, L-SIG, and HE-SIG1 transmitted on the first channel, and the HE-STF, HE-LTF, HE-SIG3, and transmitted on subchannel 2 included in the first channel. It may include a MAC payload. L-STF 900, L-LTF 910, L-SIG 920, and HE-SIG1 930 transmitted by UL MU target STA1 and L-STF, L- transmitted by UL MU target STA2 The LTF, L-SIG and HE-SIG1 contain the same information and may be transmitted on the same channel. Or L-STF 900, L-LTF 910, L-SIG 920, and HE-SIG1 930 transmitted by UL MU target STA1 and L-STF, L transmitted by UL MU target STA2 Each of the -LTF, L-SIG and HE-SIG1 may be coded by different orthogonal codes and transmitted on the same channel.

The UL MU target STA3 may transmit the UL MU PPDU3 in response to the trigger frame. The UL MU PPDU3 includes the L-STF, L-LTF, L-SIG, and HE-SIG1 transmitted on the second channel, and the HE-STF, HE-LTF, HE-SIG3, and transmitted on subchannel 3 included in the second channel. It may include a MAC payload. The UL MU target STA4 may transmit the UL MU PPDU4 in response to the trigger frame. The UL MU PPDU4 includes the L-STF, L-LTF, L-SIG and HE-SIG1 transmitted on the second channel, and the HE-STF, HE-LTF, HE-SIG3 and subchannel 4 included in the second channel. It may include a MAC payload. That is, L-STF, L-LTF, L-SIG and HE-SIG1 transmitted by UL MU target STA3 and L-STF, L-LTF, L-SIG and HE-SIG1 transmitted by UL MU target STA4 The same information may be included and transmitted on the same channel. Or L-STF, L-LTF, L-SIG and HE-SIG1 transmitted by UL MU target STA3 and L-STF, L-LTF, L-SIG and HE-SIG1 transmitted by UL MU target STA4 It may be coded by different orthogonal codes and transmitted on the same channel.

Peripheral STAs of the UL MU STA may obtain information on the allocation of the medium for transmission of the UL MU PPDU based on the length information included in the L-SIG 920, and based on the obtained information on the allocation of the medium. NAV (network allocation vector) can be set. When the neighbor STA of the UL MU STA is set to NAV, access to the medium of the neighbor STA for a predetermined period corresponding to the set value by setting the value of the NAV timer may be delayed.

10 is a conceptual diagram illustrating a UL MU PPDU transmitted by a UL MU target STA according to an embodiment of the present invention.

In FIG. 10, a UL MU PPDU transmitted by one UL MU target STA among a plurality of UL MU target STAs is disclosed. The UL MU PPDU disclosed in FIG. 10 is disclosed from the viewpoint of a STA. That is, the UL MU PPDU disclosed in FIG. 10 may be a UL MU PPDU transmitted by one UL MU target STA.

In FIG. 10, the AP allocates each of subchannel 1, subchannel 2, subchannel 3, and subchannel 4 to the UL MU target STA1, the UL MU target STA2, the UL MU target STA3, and the UL MU target STA4 based on the trigger frame. It may be assumed that triggering uplink transmission.

Referring to FIG. 10, the UL MU target STA may transmit the L-STF 1000, the L-LTF 1010, the L-SIG 1020, and the HE-SIG1 1030 on a channel-by-channel basis over the entire bandwidth.

For example, a UL MU PPDU transmitted by a UL MU target STA may be applied to the L-STF 1000, the L-LTF 1010, the L-SIG 1020, and the HE-SIG1 (the first channel and the second channel, respectively). 1030). The L-STF 1000, L-LTF 1010, and L-SIG 1020 are encoded and transmitted on the first channel and the second channel, respectively, and the HE-SIG1 1030 is the first channel and the second channel, respectively. It may be duplicated on and transmitted on each of the first channel and the second channel. The HE SIG1 1030 may include information about a transmission bandwidth of the HE-SIG2 1040.

L-STF 1000, L-LTF91010, L-SIG 1020, and HE-SIG1 1030 transmitted over the full bandwidth by UL MU target STA1, UL MU target STA2, UL MU target STA3, and UL MU target STA4, respectively ) May include the same information. Or L-STF 1000, L-LTF 1010, L-SIG 1020, and HE- transmitted over the entire bandwidth by UL MU target STA1, UL MU target STA2, UL MU target STA3, and UL MU target STA4, respectively. Each of the SIG1 1030 may be coded by different orthogonal codes and transmitted on the same channel.

According to an embodiment of the present invention, the UL MU PPDU may include a HE-SIG2 1040. The HE-SIG2 1040 may be encoded and transmitted over the entire bandwidth. The total bandwidth may be the total frequency bandwidth allocated for transmission of UL MU PPDUs of each of the plurality of UL MU target STAs by a trigger frame. The HE-SIG2 1040 may include information about each of the plurality of UL MU target STAs transmitting the UL MU PPDU based on the trigger frame. For example, the HE-SIG2 1040 may include identification information (eg, PAID and GID) of a plurality of UL MU target STAs for transmitting the UL MU PPDU. In addition, the HE-SIG2 1040 transmits the HE-STF 1050, the HE-LTF 1060, the HE-SIG3 1070, and the MAC payload 1080 of each of the plurality of UL MU target STAs on the UL MU PPDU. For example, information about resources allocated to each of the plurality of UL MU target STAs may be included. The UL MU target STA may generate the HE-SIG2 1040 based on information included in the trigger frame (for example, resource information allocated to the UL MU target STA identification information).

In addition, the UL MU PPDU transmitted by the UL MU target STA is transmitted through the allocated subchannels on the HE-STF 1050, the HE-LTF 1060, the HE-SIG3 1070, and the MAC payload 1080. It may include.

That is, in the UL MU PPDU, the L-STF (1000), the L-LTF (1010), the L-SIG (1020), and the HE-SIG1 (1030) are encoded on a channel basis and transmitted over the entire bandwidth. Is transmitted over the full bandwidth and the HE-STF 1050, HE-LTF 1060, HE-SIG3 1070, and MAC payload 1080 may be transmitted on the assigned subchannel.

The neighbor STAs of the UL MU STA may receive the HE-SIG2 1040 and obtain subchannel information allocated to the UL MU STA. The neighboring terminals of the UL MU STA may obtain information about the TXOP duration based on the UL MU PPDU based on the duration field included in the MAC payload 1080 transmitted on the subchannel allocated to the UL MU STA. That is, the neighbor STAs of the UL MU STA may obtain information on the TXOP duration based on the HE-SIG2 1040. The neighbor STAs of the UL MU STA may configure the NAV based on the information on the TXOP duration. Therefore, when the HE-SIG2 1040 is included in the UL MU PPDU, the problem of the hidden node can be solved, and performance degradation due to collision between the PPDU or the frame can be reduced.

The AP transmits the L-STF 1000, the L-LTF 1010, the L-SIG 1020, and the HE-SIG1 1030 transmitted through the first channel and the second channel by STA1, STA2, STA3, and STA4, respectively. ) And the HE-SIG2 1040 transmitted through the first channel and the second channel. In addition, the AP may transmit the HE-STF 1050, the HE-LTF 1060, and the HE- that are transmitted by the STA1, the STA2, the STA3, and the STA4 through the subchannel 1, the subchannel 2, the subchannel 3, and the subchannel 4, respectively. SIG3 1070 and MAC payload 1080 may be received.

11 is a conceptual diagram illustrating a UL MU PPDU transmitted by a UL MU target STA according to an embodiment of the present invention.

In FIG. 11, a UL MU PPDU transmitted by one UL MU target STA among a plurality of UL MU target STAs is disclosed. The UL MU PPDU disclosed in FIG. 11 is disclosed in view of a STA. That is, the UL MU PPDU disclosed in FIG. 11 may be a UL MU PPDU transmitted by one UL MU target STA.

In FIG. 11, the AP allocates each of subchannel 1, subchannel 2, subchannel 3, and subchannel 4 to each of UL MU target STA1, UL MU target STA2, UL MU target STA3, and UL MU target STA4 based on a trigger frame. It may be assumed that triggering uplink transmission.

Referring to FIG. 11, the UL MU target STA may include an L-STF 1100, an L-LTF 1110, an L-SIG 1120, an HE-SIG1 1130, and an HE- on a channel including an allocated subchannel. The SIG2 1140 may be encoded and transmitted. The HE-SIG1 1130 may include information for decoding the HE-SIG2 1140. For example, the HE-SIG1 1130 may include information about the length of the HE-SIG2 1140 (information on the number of OFDM symbols allocated to the HE-SIG2 1140).

The HE-SIG2 1140 transmitted on the channel including the subchannel may include information on at least one UL MU target STA allocated to the subchannel included on the channel. For example, the HE-SIG2 1140 may identify identification information of at least one UL MU target STA transmitting UL MU PPDU and HE-STF of at least one UL MU target STA transmitting UL MU PPDU through a first channel. 1150, the HE-LTF 1160, the HE-SIG3 1170, and the MAC payload 1180 may include information on resources allocated to at least one UL MU target STA. The length of the HE-SIG2 1140 transmitted through each of the plurality of channels included in the entire band may be set to be the same.

The L-STF 1100, L-LTF 1110, L-SIG 1120, and HE-SIG1 1130 transmitted by a plurality of UL MU target STAs transmitted on the same channel may include the same information or different information. It may be coded by an orthogonal code and transmitted on the same channel.

In other words, the UL MU PPDU may include a first field group encoded and transmitted in a unit of a channel including a subchannel, and a second field group encoded and transmitted in a unit of a subchannel.

The first field group includes a first training field (L-STF, L-LTF) and a first signal field (eg, HE-SIG2), and the second field group is later in time than the first signal field. It may include a second training field (eg, HE-STF, HE-LTF), a second signal field (eg, HE-SIG3) and a MAC payload transmitted to the AP.

The first signal field may include information on the subchannel, and the second signal field may include information for decoding the MAC payload. In addition, the first training field is used for channel prediction for the channel, the second training field is used for channel prediction for the subchannel, and the MAC payload may include downlink data transmitted from the STA to the AP. .

The representation of the PPDU based on the training field and the signal field may be applied to the other DL MU PPDUs and UL MU PPDUs described above.

12 is a conceptual diagram illustrating a HE-SIG2 field according to an embodiment of the present invention.

In FIG. 12, an HE-SIG2 including MAC header information of a MAC payload is disclosed.

The HE-SIG1 included in the UL MU PPDU includes information indicating uplink transmission of the PPDU (uplink indication information) and / or other information (eg, duration information) in which the information included in the HE-SIG2 is different. It may include change information indicating information indicating that.

For example, a reserved bit included in the HE-SIG1 may be used for uplink indication information and change information indication information.

As another example, a reserved value among lower fields included in the HE-SIG1 may be used for uplink indication information and / or change information indication information.

For example, it may be assumed that the MCS subfield including information on the MCS among the subfields included in the HE-SIG1. If 10 MCSs are defined, 4 bits may be allocated for MCS subfields. Since 4 bits may represent values of 0 to 15, 4 to 5 numbers (for example, 10, 11, 12, 13, and 14) except 10 numbers for indicating 10 MCSs may be preserved. . Accordingly, the remaining values except for the 10 for the MCS lower field indicating the MCS may be used as uplink indication information and / or change information indication information. Hereinafter, it is assumed that the duration information is included as other information in the HE-SIG.

Referring to FIG. 12, the HE-SIG2 included in the UL MU PPDU may include duration information of a MAC header.

In FIG. 12, HE-SIG2 of 1 OFDM symbol is assumed, and HE-SIG2 may include information corresponding to 24 bits or 26 bits.

The HE-SIG2 may include a duration field, a CRC bit, and a tail bit as a lower field. The duration information may be included in the duration field. The CRC bit may be used to determine whether the duration field is in error, and the Tail bit may be used to return the convolutional encoder to a zero state. The duration bit may be 16 bits, the CRC bit may be 2 (or 4 bits), and the tail bit may be 6 bits.

If the CRC bits are insufficient, some bits allocated for the duration field are used as the CRC bits, and the number of bits for the duration field can be reduced.

When the bit for the duration field is reduced, the scale indicating the size of the duration may be changed. For example, if the unit of the value indicated by the duration field is 1usec (micro second) before the bit for the duration field is reduced, the unit of the value indicated by the duration field is 2usec after the bit for the duration field is reduced. Can be increased to 4usec. That is, if the value indicated by the duration field changes by 1 before the bit for the duration field is decreased, if a change in the duration difference of 1usec is indicated, the value indicated by the duration field after the bit for the duration field is reduced. If this is changed by 1, a change in the duration difference of 2usec or 4usec may be indicated.

If two or more OFDM symbols are allocated for HE-SIG2, the number of CRC bits may be increased and the robustness to errors in the duration field may increase.

The duration information may be determined by duration information for a UL MU transmission procedure included in a trigger frame transmitted to a plurality of UL MU target STAs. Accordingly, the duration information included in the HE-SIG2 included in the plurality of UL MU PPDUs transmitted by each of the plurality of UL MU target STAs may be the same.

In other words, the UL MU PPDU may include a first field group encoded and transmitted in a unit of a channel including a subchannel, and a second field group encoded and transmitted in a unit of a subchannel.

The first field group includes a first training field (eg, L-STF, L-LTF) and a first signal field (eg, HE-SIG2), and the second field group is less than the first signal field. It may include a second training field (HE-STF, HE-LTF), a second signal field (HE-SIG3), and a medium access control (MAC) payload transmitted to the AP later in time.

The first signal field may include first duration information and the second signal field may include information for decoding the MAC payload. The first training field may be used for channel prediction for the channel, and the second training field may be used for channel prediction for the subchannel.

In addition, the MAC header included in the MAC payload includes second duration information, and the aforementioned first duration information and the second duration information are based on the duration information for the transmission procedure of the UL MU PPDU transmitted through the trigger frame. Can be determined.

In addition, the first field group may further include a third signal field (eg, HE-SIG1) transmitted to the AP in advance of the first signal field, and the third signal field may be added to the first signal field. It may include information indicating whether 1 duration information is included.

13 is a block diagram illustrating a wireless device to which an embodiment of the present invention can be applied.

Referring to FIG. 13, the AP 1300 includes a processor 1310, a memory 1320, and an RF unit 1330.

The RF unit 1330 may be connected to the processor 1310 to transmit / receive a radio signal.

The processor 1310 may implement the functions, processes, and / or methods proposed in the present invention. For example, the processor 1310 may be implemented to perform the operation of the AP according to the above-described embodiment of the present invention. The processor may perform the operation of the AP disclosed in the embodiment of FIGS. 1 to 12.

For example, the processor 1310 may include L-STF, L-LTF, L-SIG and HE-SIG1 encoded in a plurality of subchannel units (or channel units), HE-SIG2 encoded in full band or channel units, and It can be implemented to generate a DL MU PPDU including HE-STF, HE-LTF, HE-SIG3 and MAC payload encoded in sub-channel units.

The STA 1350 includes a processor 1360, a memory 1370, and an RF unit 1380.

The RF unit 1380 may be connected to the processor 1360 to transmit / receive a radio signal.

The processor 1360 may implement the functions, processes, and / or methods proposed in the present invention. For example, the processor 1360 may be implemented to perform the operation of the STA according to the above-described embodiment of the present invention. The processor may perform an operation of the STA in the embodiment of FIGS. 1 to 12.

For example, the processor 1360 may be implemented to receive a trigger frame from the AP and transmit a UL MU PPDU to the AP on a subchannel in response to the trigger frame. In addition, the processor 1360 may include a UL MU PPDU including a first field group encoded and transmitted in a unit of a channel including a subchannel and a second field group encoded and transmitted in a unit of a subchannel.

Processors 1310 and 1360 may include application-specific integrated circuits (ASICs), other chipsets, logic circuits, data processing devices, and / or converters for interconverting baseband signals and wireless signals. The memories 1320 and 1370 may include read-only memory (ROM), random access memory (RAM), flash memory, memory cards, storage media, and / or other storage devices. The RF unit 1330 and 1380 may include one or more antennas for transmitting and / or receiving a radio signal.

When the embodiment is implemented in software, the above-described technique may be implemented as a module (process, function, etc.) for performing the above-described function. The module may be stored in the memories 1320 and 1370 and executed by the processors 1310 and 1360. The memories 1320 and 1370 may be inside or outside the processors 1310 and 1360, and may be connected to the processors 1310 and 1360 by various well-known means.

Claims (10)

1. In the WLAN, a data unit transmission method is
   A station (STA) receiving a trigger frame from an access point (AP); And
   Transmitting, by the STA, a UL uplink multi user PHY protocol data unit (UL MU PPDU) to the AP on a subchannel in response to the trigger frame,
   The trigger frame includes UL MU identification information and UL MU resource allocation information,
   The UL MU identification information includes identification information of the STA and identification information of another STA transmitting another UL MU PPDU on a time resource overlapped with the STA,
   The UL MU resource allocation information includes information on the subchannel and other subchannels for transmitting the other UL MU PPDU,
   The UL MU PPDU includes a first field group encoded and transmitted in a unit of a channel including the subchannel, and a second field group encoded and transmitted in a unit of the subchannel.
2. The method of claim 1,
   The first field group includes a first training field and a first signal field,
   The second field group includes a second training field, a second signal field, and a medium access control (MAC) payload transmitted to the AP in time later than the first signal field,
   The first signal field includes information about the sub channel.
   The second signal field includes information for decoding the MAC payload,
   The first training field is used for channel prediction for the channel,
   The second training field is used for channel prediction for the subchannel,
   The MAC payload includes downlink data transmitted from the STA to the AP.
3. The method of claim 1,
   The first field group includes a first training field and a first signal field,
   The second field group includes a second training field, a second signal field, and a medium access control (MAC) payload transmitted to the AP in time later than the first signal field,
   The first signal field includes first duration information.
   The second signal field includes information for decoding the MAC payload,
   The first training field is used for channel prediction for the channel,
   The second training field is used for channel prediction for the subchannel,
   The MAC header included in the MAC payload includes second duration information.
   Wherein the first duration information and the second duration information are determined based on duration information for a transmission procedure of the UL MU PPDU transmitted through the trigger frame.
4. The method of claim 3,
   The first field group further includes a third signal field transmitted to the AP in time ahead of the first signal field,
   And wherein the third signal field includes information indicating whether the first duration information is included in the first signal field.
5. The method of claim 1,
   The bandwidth of the channel is 20 MHz,
   And the bandwidth of the subchannel is 10 MHz.
6. In a STA for transmitting a data unit in a WLAN, the STA
   A radio frequency (RF) unit implemented to transmit or receive a radio signal; And
   A processor operatively connected with the RF unit,
   The processor receives a trigger frame from an access point,
   In response to the trigger frame is implemented to transmit a UL uplink multi user PHY protocol data unit (MU DUPDU) to the AP on a subchannel
   The trigger frame includes UL MU identification information and UL MU resource allocation information,
   The UL MU identification information includes identification information of the STA and identification information of another STA transmitting another UL MU PPDU on a time resource overlapped with the STA,
   The UL MU resource allocation information includes information on the subchannel and other subchannels for transmitting the other UL MU PPDU,
   The UL MU PPDU includes a first field group encoded and transmitted in a unit of a channel including the subchannel, and a second field group encoded and transmitted in a unit of the subchannel.
7. The method of claim 6,
   The first field group includes a first training field and a first signal field,
   The second field group includes a second training field, a second signal field, and a medium access control (MAC) payload transmitted to the AP in time later than the first signal field,
   The first signal field includes information about the sub channel.
   The second signal field includes information for decoding the MAC payload,
   The first training field is used for channel prediction for the channel,
   The second training field is used for channel prediction for the subchannel,
   The MAC payload includes downlink data transmitted from the STA to the AP.
8. The method of claim 6,
   The first field group includes a first training field and a first signal field,
   The second field group includes a second training field, a second signal field, and a medium access control (MAC) payload transmitted to the AP in time later than the first signal field,
   The first signal field includes first duration information.
   The second signal field includes information for decoding the MAC payload,
   The first training field is used for channel prediction for the channel,
   The second training field is used for channel prediction for the subchannel,
   The MAC header included in the MAC payload includes second duration information.
   The first duration information and the second duration information are determined based on duration information for a transmission procedure of the UL MU PPDU transmitted through the trigger frame.
9. The method of claim 8,
   The first field group further includes a third signal field transmitted to the AP in time ahead of the first signal field,
   And the third signal field includes information indicating whether the first duration information is included in the first signal field.
10. The method of claim 6,
    The bandwidth of the channel is 20 MHz,
    The bandwidth of the subchannel is STA, characterized in that 10MHz.

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