WO2016190578A1 - Method for transmitting wireless frame including multiple signaling fields, and device for same - Google Patents

Abstract

According to one embodiment of the present invention, a method by which an access point (AP) transmits a wireless frame in a wireless LAN system generates, by the AP, a wireless frame including a signaling field and a data field, wherein, when the wireless frame is to transmit data to a plurality of STAs, the signaling field includes a first signaling field (SIG A field) including first common control information for the plurality of STAs, and a second signaling field (SIG B field) including individual control information for the respective plurality of STAs, and the second signaling field includes a common field including second common control information for the plurality of STAs, and an individual field following the common field and including individual control information for the respective plurality of STAs. The AP can transmit the generated wireless frame to one or more STAs.

Description

Method for transmitting radio frame including multiple signaling fields and apparatus for same

This document relates to a WLAN system, and more particularly, to a method and apparatus for constructing and efficiently transmitting a radio frame including various signaling fields in a WLAN system.

The proposed frame transmission method may be applied to various wireless communications, but the following describes a wireless local area network (WLAN) system as an example to which the present invention may be applied.

The standard for WLAN technology is being developed as an Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard. IEEE 802.11a and b are described in 2.4. Using unlicensed band at GHz or 5 GHz, IEEE 802.11b provides a transmission rate of 11 Mbps and IEEE 802.11a provides a transmission rate of 54 Mbps. IEEE 802.11g applies orthogonal frequency-division multiplexing (OFDM) at 2.4 GHz to provide a transmission rate of 54 Mbps. IEEE 802.11n applies multiple input multiple output OFDM (MIMO-OFDM) to provide a transmission rate of 300 Mbps for four spatial streams. IEEE 802.11n supports channel bandwidths up to 40 MHz, in this case providing a transmission rate of 600 Mbps.

The WLAN standard uses a maximum of 160MHz bandwidth, supports eight spatial streams, and supports IEEE 802.11ax standard through an IEEE 802.11ac standard supporting a speed of up to 1Gbit / s.

The present invention proposes an efficient radio frame structure in the WLAN system as described above, and provides a method for efficiently transmitting and receiving data using the same.

The present invention is not limited to the above-described technical problem and other technical problems can be inferred from the embodiments of the present invention.

In a wireless LAN system according to an aspect of the present invention for achieving the above technical problem, a method of transmitting an radio frame to one or more stations (STA), the AP includes a signaling field and a data field in the AP Generates a radio frame, but when the radio frame is a radio frame for transmitting data to a plurality of STAs, the signaling field includes a first signaling field (SIG) including first common control information for the plurality of STAs. A field) and a second signaling field (SIG B field) including individual control information in each of the plurality of STAs, wherein the second signaling field includes common common information including second common control information for the plurality of STAs. Field, and a separate field subsequent to the common field and including individual control information in each of the plurality of STAs; Transmitting a line frame to the at least one STA, it proposes a radio frame transmission method.

When the radio frame is a radio frame for transmitting data to one STA, the second signaling field of the radio frame may not include the individual field. Unlike this, the radio frame transmits data to one STA. In the case of a radio frame, the radio frame may not include the second signaling field.

The first signaling field may include interpretation information about the second signaling field. The common field of the second signaling field may include information about the number of the plurality of STAs and allocation resource information. In addition, the individual field of the second signaling field may include identifier information for each of the plurality of STAs, information on the number of spatial streams, information on whether to use transmission beamforming, and coding information.

Meanwhile, the second signaling field may be configured in 20 MHz band units.

In addition, the signaling field of a specific 20 MHz band may include resource allocation information for a 20 MHz band other than the specific 20 MHz band.

The resource allocation information includes a plurality of resource structures including a resource structure divided into 26 tones for each 20 MHz band, a resource structure divided into 52 tones, a resource structure divided into 106 tones, and a resource structure divided into 242 tones. A resource may be allocated based on one of the resource structures.

The radio frame may have a form of a physical protocol data unit (PPDU).

In another aspect of the present invention, an access point (AP) apparatus for transmitting a radio frame to one or more stations (STA) in a WLAN system, comprising: a processor configured to generate a radio frame including a signaling field and a data field; And a transceiver coupled to the processor and configured to transmit the radio frame to the at least one STA, wherein the processor is configured to: when the radio frame is a radio frame for transmitting data to a plurality of STAs, the signaling field Includes a first signaling field (SIG A field) including first common control information for the plurality of STAs and a second signaling field (SIG B field) including individual control information in each of the plurality of STAs, The AP device is configured to include the second signaling field to include a common field including second common control information for the plurality of STAs and an individual field including individual control information in each of the plurality of STAs.

When the radio frame is a radio frame for transmitting data to one STA, the processor may be configured not to include the individual field in a second signaling field of the radio frame.

In addition, when the radio frame is a radio frame for transmitting data to one STA, the processor may configure the radio frame not to include the second signaling field.

The processor may configure the second signaling field in units of 20 MHz band.

The processor may be configured to include resource allocation information for a 20 MHz band other than the specific 20 MHz band in the signaling field of a specific 20 MHz band.

According to an embodiment of the present invention, when the radio frame is a multi-user radio frame, it is possible to improve the radio communication performance by allowing the receiver to efficiently acquire control information.

In addition, the overhead may be reduced by configuring differently depending on whether the radio frame is a multi-user radio frame or a single user radio frame.

In addition, resource allocation can be made flexible in each band, thereby increasing resource efficiency.

The effects of the present invention are not limited to the above-mentioned effects, and other effects not mentioned above may be clearly understood by those skilled in the art from the following description.

1 is a diagram illustrating an example of a configuration of a WLAN system.

2 is a diagram illustrating another example of a configuration of a WLAN system.

3 is a diagram illustrating an exemplary structure of a WLAN system.

4 is a view for explaining a general link setup process.

5 is a diagram for describing an active scanning method and a passive scanning method.

6 to 8 are views for explaining the operation of the station receiving the TIM in detail.

9 to 13 are diagrams for explaining an example of the frame structure used in the IEEE 802.11 system.

14 to 16 illustrate a MAC frame format.

17 illustrates a Short MAC frame format.

18 illustrates an example of a high efficiency (HE) PPDU format according to an embodiment of the present invention.

19 is a diagram for explaining a HE-SIG B configuration in a multi-user PPDU according to one embodiment of the present invention.

20 is a diagram illustrating an example of a configuration of an HE-SIG B when transmitting a single user PPDU according to an embodiment of the present invention.

FIG. 21 illustrates a chunk size of an allocation that an STA can use in a 20 MHz channel according to an embodiment of the present invention.

22 is a block diagram illustrating an exemplary configuration of an AP device (or base station device) and a station device (or terminal device) according to an embodiment of the present invention.

23 illustrates an exemplary structure of a processor of an AP device or a station device according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. The detailed description, which will be given below with reference to the accompanying drawings, is intended to explain exemplary embodiments of the present invention and is not intended to represent the only embodiments in which the present invention may be practiced. The following detailed description includes specific details in order to provide a thorough understanding of the present invention. However, one of ordinary skill in the art appreciates that the present invention may be practiced without these specific details.

The following embodiments combine the components and features of the present invention in a predetermined form. Each component or feature may be considered to be optional unless otherwise stated. Each component or feature may be embodied in a form that is not combined with other components or features. In addition, some components and / or features may be combined to form an embodiment of the present invention. The order of the operations described in the embodiments of the present invention may be changed. Some components or features of one embodiment may be included in another embodiment or may be replaced with corresponding components or features of another embodiment.

Specific terms used in the following description are provided to help the understanding of the present invention, and the use of such specific terms may be changed to other forms without departing from the technical spirit of the present invention.

In some instances, well-known structures and devices are omitted or shown in block diagram form, centering on the core functions of each structure and device, in order to avoid obscuring the concepts of the present invention. In addition, the same components will be described with the same reference numerals throughout the present specification.

Embodiments of the present invention may be supported by standard documents disclosed in at least one of the wireless access systems IEEE 802 system, 3GPP system, 3GPP LTE and LTE-A (LTE-Advanced) system and 3GPP2 system. That is, steps or parts which are not described to clearly reveal the technical spirit of the present invention among the embodiments of the present invention may be supported by the above documents. In addition, all terms disclosed in the present document can be described by the above standard document.

The following techniques include code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), single carrier frequency division multiple access (SC-FDMA), and the like. It can be used in various radio access systems. CDMA may be implemented with a radio technology such as Universal Terrestrial Radio Access (UTRA) or CDMA2000. TDMA may be implemented with wireless technologies such as Global System for Mobile communications (GSM) / General Packet Radio Service (GPRS) / Enhanced Data Rates for GSM Evolution (EDGE). OFDMA may be implemented in a wireless technology such as IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, Evolved UTRA (E-UTRA).

In addition, terms such as first and / or second may be used herein to describe various components, but the components should not be limited by the terms. The terms are only for the purpose of distinguishing one component from another component, for example, without departing from the scope of rights in accordance with the concepts herein, the first component may be called a second component, and similarly The second component may also be referred to as a first component.

In addition, throughout the specification, when a part is said to "include" a certain component, it means that it can further include other components, except to exclude other components unless otherwise stated. And “…” described in the specification. unit", "… “Unit” refers to a unit that processes at least one function or operation, which may be implemented in a combination of hardware and / or software.

1 is a diagram illustrating an example of a configuration of a WLAN system.

As shown in FIG. 1, the WLAN system includes one or more basic service sets (BSSs). A BSS is a set of stations (STAs) that can successfully synchronize and communicate with each other.

A station is a logical entity that includes medium access control (MAC) and a physical layer interface to a wireless medium. The station is an access point (AP) and a non-AP station. Include. The portable terminal operated by the user among the stations is a non-AP station, which is simply referred to as a non-AP station. A non-AP station is a terminal, a wireless transmit / receive unit (WTRU), a user equipment (UE), a mobile station (MS), a mobile terminal, or a mobile subscriber. It may also be called another name such as a mobile subscriber unit.

The AP is an entity that provides an associated station with access to a distribution system (DS) through a wireless medium. The AP may be called a centralized controller, a base station (BS), a Node-B, a base transceiver system (BTS), or a site controller.

BSS can be divided into infrastructure BSS and Independent BSS (IBSS).

The BBS shown in FIG. 1 is an IBSS. The IBSS means a BSS that does not include an AP. Since the IBSS does not include an AP, access to the DS is not allowed, thereby forming a self-contained network.

2 is a diagram illustrating another example of a configuration of a WLAN system.

The BSS shown in FIG. 2 is an infrastructure BSS. The infrastructure BSS includes one or more stations and an AP. In the infrastructure BSS, communication between non-AP stations is performed via an AP, but direct communication between non-AP stations is also possible when a direct link is established between non-AP stations.

As shown in FIG. 2, a plurality of infrastructure BSSs may be interconnected through a DS. A plurality of BSSs connected through a DS is called an extended service set (ESS). Stations included in an ESS may communicate with each other, and a non-AP station may move from one BSS to another BSS while communicating seamlessly within the same ESS.

The DS is a mechanism for connecting a plurality of APs. The DS is not necessarily a network, and there is no limitation on the form if it can provide a predetermined distribution service. For example, the DS may be a wireless network such as a mesh network or a physical structure that connects APs to each other.

3 is a diagram illustrating an exemplary structure of a WLAN system. In FIG. 3, an example of an infrastructure BSS including a DS is shown.

In the example of FIG. 3, BSS1 and BSS2 constitute an ESS. In a WLAN system, a station is a device that operates according to MAC / PHY regulations of IEEE 802.11. The station includes an AP station and a non-AP station. Non-AP stations are typically user-managed devices, such as laptop computers and mobile phones. In the example of FIG. 3, station 1, station 3, and station 4 correspond to non-AP stations, and station 2 and station 5 correspond to AP stations.

In the following description, a non-AP station includes a terminal, a wireless transmit / receive unit (WTRU), a user equipment (UE), a mobile station (MS), and a mobile terminal. May be referred to as a Mobile Subscriber Station (MSS). In addition, the AP may include a base station (BS), a node-B, an evolved Node-B (eNB), and a base transceiver system (BTS) in other wireless communication fields. , A concept corresponding to a femto base station (Femto BS).

FIG. 4 is a diagram illustrating a general link setup process, and FIG. 5 is a diagram illustrating an active scanning method and a passive scanning method.

In order for a station to set up a link and transmit and receive data over a network, it first discovers the network, performs authentication, establishes an association, and authenticates for security. It must go through the back. The link setup process may also be referred to as session initiation process and session setup process. In addition, the process of discovery, authentication, association and security establishment of the link setup process may be collectively referred to as association process.

An exemplary link setup procedure will be described with reference to FIG. 4.

In step S410, the station may perform a network discovery operation. The network discovery operation may include a scanning operation of the station. In other words, in order for a station to access a network, it must find a network that can participate. The station must identify a compatible network before joining the wireless network. Network identification in a particular area is called scanning.

There are two types of scanning methods, active scanning and passive scanning. 4 exemplarily illustrates a network discovery operation including an active scanning process, but may operate as a passive scanning process.

In active scanning, a station performing scanning transmits a probe request frame and waits for a response to discover which AP exists in the vicinity while moving channels. The responder transmits a probe response frame in response to the probe request frame to the station transmitting the probe request frame. Here, the responder may be the station that last transmitted the beacon frame in the BSS of the channel being scanned. In the BSS, the AP transmits a beacon frame, so the AP becomes a responder. In the IBSS, the responder is not constant because the stations in the IBSS rotate and transmit the beacon frame. For example, a station that transmits a probe request frame on channel 1 and receives a probe response frame on channel 1 stores the BSS-related information included in the received probe response frame and stores the next channel (for example, number 2). Channel) to perform scanning (i.e., probe request / response transmission and reception on channel 2) in the same manner.

In addition, referring to FIG. 5, the scanning operation may be performed by a passive scanning method. In passive scanning, a station performing scanning waits for a beacon frame while moving channels. Beacon frame is one of the management frame (management frame) in IEEE 802.11, it is transmitted periodically to inform the existence of the wireless network, and to perform the scanning station to find the wireless network and join the wireless network. In the BSS, the AP periodically transmits a beacon frame, and in the IBSS, stations in the IBSS rotate to transmit a beacon frame. When the scanning station receives the beacon frame, the scanning station stores the information about the BSS included in the beacon frame and records beacon frame information in each channel while moving to another channel. The station receiving the beacon frame may store the BSS related information included in the received beacon frame, move to the next channel, and perform scanning on the next channel in the same manner.

Comparing active and passive scanning, active scanning has the advantage of less delay and power consumption than passive scanning.

After the station has found the network, the authentication process may be performed in step S420. This authentication process may be referred to as a first authentication process in order to clearly distinguish from the security setup operation of step S440 described later.

The authentication process includes a process in which the station transmits an authentication request frame to the AP, and in response thereto, the AP transmits an authentication response frame to the station. An authentication frame used for authentication request / response corresponds to a management frame.

The authentication frame includes an authentication algorithm number, an authentication transaction sequence number, a status code, a challenge text, a Robust Security Network, and a finite cyclic group. Group) and the like. This corresponds to some examples of information that may be included in the authentication request / response frame, and may be replaced with other information or further include additional information.

The station may send an authentication request frame to the AP. The AP may determine whether to allow authentication for the corresponding station based on the information included in the received authentication request frame. The AP may provide the station with the result of the authentication process through an authentication response frame.

After the station is successfully authenticated, the association process may be performed in step S430. The association process includes the station transmitting an association request frame to the AP, and in response, the AP transmitting an association response frame to the station.

For example, the association request frame may include information related to various capabilities, beacon listening interval, service set identifier (SSID), supported rates, supported channels, RSN, mobility domain. Information about supported operating classes, TIM Broadcast Indication Map Broadcast request, interworking service capability, and the like.

For example, the association response frame may include information related to various capabilities, status codes, association IDs (AIDs), support rates, Enhanced Distributed Channel Access (EDCA) parameter sets, Received Channel Power Indicators (RCPI), Received Signal to Noise Information) such as an indicator, a mobility domain, a timeout interval (association comeback time), an overlapping BSS scan parameter, a TIM broadcast response, and a QoS map.

This corresponds to some examples of information that may be included in the association request / response frame, and may be replaced with other information or further include additional information.

After the station is successfully associated with the network, a security setup procedure may be performed at step S540. The security setup process of step S440 may be referred to as an authentication process through a Robust Security Network Association (RSNA) request / response. The authentication process of step S520 is called a first authentication process, and the security setup process of step S540 is performed. It may also be referred to simply as the authentication process.

The security setup process of step S440 may include, for example, performing a private key setup through 4-way handshaking through an Extensible Authentication Protocol over LAN (EAPOL) frame. . In addition, the security setup process may be performed according to a security scheme not defined in the IEEE 802.11 standard.

6 to 8 are views for explaining the operation of the station receiving the TIM in detail.

Referring to FIG. 6, a station transitions from a sleep state to an awake state to receive a beacon frame including a traffic indication map (TIM) from an AP, interprets the received TIM element, and buffers traffic to be transmitted to itself. It can be seen that. The station may transmit a PS-Poll frame to request an AP to transmit a data frame after contending with other stations for medium access for PS-Poll frame transmission. The AP receiving the PS-Poll frame transmitted by the station may transmit the frame to the station. The station may receive a data frame and send an acknowledgment (ACK) frame thereto to the AP. The station may then go back to sleep.

As shown in FIG. 6, the AP operates according to an immediate response method of transmitting a data frame after a predetermined time (for example, short inter-frame space) after receiving a PS-Poll frame from a station. Can be. On the other hand, when the AP does not prepare a data frame to be transmitted to the station after receiving the PS-Poll frame during the SIFS time, it may operate according to the delayed response (deferred response) method, which will be described with reference to FIG.

In the example of FIG. 7, an operation in which the station transitions from the sleep state to the awake state, receives a TIM from the AP, and transmits a PS-Poll frame to the AP through contention is the same as the example of FIG. 6. If the AP does not prepare a data frame during SIFS even after receiving the PS-Poll frame, the AP may transmit an ACK frame to the station instead of transmitting the data frame. When the data frame is prepared after transmitting the ACK frame, the AP may transmit the data frame to the station after performing contention. The station may send an ACK frame indicating that the data frame was successfully received to the AP and go to sleep.

8 illustrates an example in which the AP transmits a DTIM. Stations may transition from a sleep state to an awake state to receive a beacon frame containing a DTIM element from the AP. The stations may know that a multicast / broadcast frame will be transmitted through the received DTIM. The AP may transmit data (ie, multicast / broadcast frame) immediately after the beacon frame including the DTIM without transmitting and receiving the PS-Poll frame. The stations may receive data while continuing to awake after receiving the beacon frame including the DTIM, and may go back to sleep after the data reception is complete.

9 to 13 are diagrams for explaining an example of the frame structure used in the IEEE 802.11 system.

The station STA may receive a Physical Layer Convergence Protocol (PLCP) Packet Data Unit (PPDU). In this case, the PPDU frame format may include a Short Training Field (STF), a Long Training Field (LTF), a SIG (SIGNAL) field, and a Data field. In this case, as an example, the PPDU frame format may be set based on the type of the PPDU frame format.

As an example, the non-HT (High Throughput) PPDU frame format may include only a legacy-STF (L-STF), a legacy-LTF (L-LTF), a SIG field, and a data field.

In addition, the type of the PPDU frame format may be set to any one of the HT-mixed format PPDU and the HT-greenfield format PPDU. In this case, the above-described PPDU format may further include an additional (or other type) STF, LTF, and SIG fields between the SIG field and the data field.

Also, referring to FIG. 10, a VHT (Very High Throughput) PPDU format may be set. In this case, an additional (or other type) STF, LTF, SIG field may be included between the SIG field and the data field in the VHT PPDU format. More specifically, in the VHT PPDU format, at least one or more of a VHT-SIG-A field, a VHT-STF field, VHT-LTF, and VHT SIG-B field may be included between the L-SIG field and the data field.

In this case, the STF may be a signal for signal detection, automatic gain control (AGC), diversity selection, precise time synchronization, or the like. In addition, the LTF may be a signal for channel estimation, frequency error estimation, or the like. In this case, the STF and the LTF may be referred to as a PLCP preamble, and the PLCP preamble may be referred to as a signal for synchronization and channel estimation of the OFDM physical layer.

In addition, referring to FIG. 11, the SIG field may include a RATE field and a LENGTH field. The RATE field may include information about modulation and coding rate of data. The LENGTH field may include information about the length of data. In addition, the SIG field may include a parity bit, a SIG TAIL bit, and the like.

The data field may include a SERVICE field, a PLC Service Data Unit (PSDU), a PPDU TAIL bit, and may also include a padding bit if necessary.

At this time, referring to FIG. 12, some bits of the SERVICE field may be used for synchronization of the descrambler at the receiving end, and some bits may be configured as reserved bits. The PSDU corresponds to a MAC PDU (Protocol Data Unit) defined in the MAC layer and may include data generated / used in an upper layer. The PPDU TAIL bit can be used to return the encoder to zero. The padding bit may be used to adjust the length of the data field in a predetermined unit.

In addition, as an example, as described above, the VHT PPDU format may include additional (or other types of) STF, LTF, and SIG fields. In this case, L-STF, L-LTF, and L-SIG in the VHT PPDU may be a portion for the Non-VHT of the VHT PPDU. In this case, VHT-SIG-A, VHT-STF, VHT-LTF, and VHT-SIG-B in the VHT PPDU may be a part for the VHT. That is, in the VHT PPDU, a field for the Non-VHT and a region for the VHT field may be defined, respectively. In this case, as an example, the VHT-SIG-A may include information for interpreting the VHT PPDU.

In this case, as an example, referring to FIG. 13, VHT-SIG-A may be configured of VHT SIG-A1 (FIG. 13A) and VHT SIG-A2 (FIG. 13B). In this case, the VHT SIG-A1 and the VHT SIG-A2 may be configured with 24 data bits, respectively, and the VHT SIG-A1 may be transmitted before the VHT SIG-A2. At this time, the VHT SIG-A1 may include a BW, STBC, Group ID, NSTS / Partial AID, TXOP_PS_NOT_ALLOWED field, and Reserved field. VHT SIG-A2 also includes Short GI, Short GI NSYM Disambiguation, SU / MU [0] Coding, LDPC Extra OFDM Symbol, SU VHT-MCS / MU [1-3] Coding, Beamformed, CRC, Tail and Reserved fields. It may include. Through this, it is possible to check the information on the VHT PPDU.

14 to 16 illustrate a MAC frame format.

The station may receive a PPDU based on any one of the above-described PPDU formats. In this case, the PSDU of the data portion of the PPDU frame format may include a MAC PDU. In this case, the MAC PDU is defined according to various MAC frame formats, and the basic MAC frame may be composed of a MAC header, a frame body, and a frame check sequence (FCS).

In this case, as an example, referring to FIG. 14, the MAC header may include a frame control field, a duration / ID field, an address field, a sequence control, a QoS control, and a HT control subfield. have. In this case, the frame control field of the MAC header may include control information required for frame transmission / reception. The interval / ID field may be set to a time for transmitting a corresponding frame. In addition, the address field may include identification information about the sender and the receiver, which will be described later. In addition, the Sequence Control, QoS Control, and HT Control fields may refer to the IEEE 802.11 standard document.

In this case, as an example, the HT Control field may have two forms as an HT variant and a VHT variant. In this case, the information included in the HT Control field may vary according to each type. 15 and 16, the VHT subfield of the HT Control may be a field indicating whether the HT Control field is a HT variant or a VHT variant. In this case, as an example, when the VHT subfield has a value of "0", it may be in the form of HT variant, and when the VHT subfield has a value of "1", it may be in the form of VHT variant.

At this time, as an example, referring to FIG. 15, if the HT Control field is a HT variant, Link Adaptation Control, Calibration Position, Calibration Sequence, CSI / Steering, HT NDP Announcement, AC constraint, RDG / More PPDU, Reserved field, etc. It may include. At this time, as an example, referring to b of FIG. 15, the Link Adaptation Control field may include a TRQ, MAI, MFSI, and MFB / ASELC field. For more details, refer to the IEEE802.11 standard document.

Also, as an example, referring to FIG. 16, if the HT Control field is a VHT variant type, MRQ, MSI, MFSI / GID-LM, MFB GID-H, Coding Type, FB Tx Type, FB Tx Type, Unsolicited MFB, AC It can include constraints, RDG / More PPDUs, and Reserved fields. In this case, as an example, referring to b of FIG. 16, the MFB field may include a VHT N_STS, MCS, BW, SNR field, and the like.

17 illustrates a Short MAC frame format. The MAC frame may be configured in the form of a short MAC frame in order to prevent unnecessary waste of information by reducing unnecessary information. In this case, as an example, referring to FIG. 17, the MAC header of a short frame may always include a frame control field, an A1 field, and an A2 field. In addition, the Sequence Control field, the A3 field, and the A4 field may be selectively included. In this way, unnecessary information may be omitted from the MAC frame to prevent waste of radio resources.

At this time, as an example, when looking at the frame control field of the MAC header, Protocol Version, Type, PTID / Subtype, From DS, More Fragment, Power Management, More Data, Protected Frame, End of Service Period, Relayed Frame and Ack Policy fields It may include. The content of each subfield of the frame control field may refer to an IEEE 802.11 standard document.

On the other hand, the Type (Field) field of the frame control field of the MAC header is composed of 3 bits, the value 0 to 3 includes the configuration for each address information, 4-7 may be reserved. In this regard, in the present invention, new address information may be indicated through a reserved value, which will be described later.

Also, the From DS field of the control frame field of the MAC header may be configured with 1 bit.

In addition, in addition, the More Fragment, Power Management, More Data, Protected Frame, End of Service Period, Relayed Frame and Ack Policy fields may be configured as 1 bit. In this case, the Ack Policy field may be configured with 1 bit as ACK / NACK information.

In relation to stations including a frame configured in the above-described form, a VHT AP may support a non-AP VHT station operating in a TXOP (Transmit Opportunity) power save mode in one BSS. In this case, as an example, the non-AP VHT station may be operating in the TXOP power save mode as an active state. At this time, the AP VHT station may be configured to switch the non-AP VHT station to the doze state during the TXOP. In this case, as an example, the AP VHT station may indicate that the TXVECTOR parameter TXOP_PS_NOT_ALLOWED is set to a value of 0 and that the AP VHT station is switched to an inactive state by transmitting a VHT PPDU. At this time, parameters in the TXVECTOR transmitted together with the VHT PPDU by the AP VHT station may be changed from 1 to 0 during TXOP. Through this, power saving can be performed for the remaining TXOP.

On the contrary, when TXOP_PS_NOT_ALLOWED is set to 1 and power saving is not performed, the parameters in the TXVECTOR may be maintained without changing.

For example, as described above, when the non-AP VHT station is switched to inactive during TXOP in the TXOP power save mode, the following condition may be satisfied.

When the VHT MU PPDU is received and the station is not indicated as a member of the group by the RXVECTOR parameter Group_ID.

If the station has received a SU PPDU and the station does not match the partial AID of the station or the PARTIAL_AID of the RXVECTOR parameter is 0

The station determines that the RXVECTOR parameter PARTIAL_AID matches the station's partial AID, but the recipient address in the MAC header does not match the station's MAC address.

-The station is indicated as a member of the group by the RXVECTOR parameter GROUP_ID, but the NUM_STS parameter of the RXVECTOR parameter is set to 0.

If a VHT NDP Announcement frame is received and the station has the RXVECTOR parameter PARTIAL_AID set to 0 and the AID in the Info field of the station does not match

When the station receives a frame in which the More Data field is set to 0, the Ack Policy subfield is set to No Ack, or sends an ACK with the Ack Policy subfield set to No Ack.

At this time, the AP VHT station may include a Duration / ID value and a NAV-SET Sequence (e.g., RTS / CTS) set to the remaining TXOP interval. In this case, the AP VHT station may not transmit a frame for the non-AP VHT station which is switched to the inactive state based on the above conditions for the remaining TXOP.

Also, as an example, if an AP VHT station transmits a VHT PPDU together with the TXVECTOR parameter TXOP_PS_NOT_ALLOWED in the same TXOP with the TXVECTOR parameter set to 0 and the station does not want to change from active to inactive, the AP VHT station sends a VHT SU PPDU. May not transmit.

Also, as an example, the AP VHT station may not transmit a frame to the VHT station which is switched to an inactive state before the NAV set when the TXOP starts.

In this case, when the AP VHT station does not receive an ACK after transmitting a frame including at least one of MSDU, A-MSDU, and MMPDU while the More Data field is set to 0, the AP VHT station may be retransmitted at least once in the same TXOP. . In this case, as an example, when ACK for retransmission is not received in the last frame of the same TXOP, the frame may be retransmitted until the next TXOP.

Also, as an example, the AP VHT station may receive a BlockAck frame from the VHT station operating in the TXOP power save mode. In this case, the BlockAck frame may be a response to the A-MPDU including the MPDU in which the More Data field is set to zero. At this time, since the AP VHT station is in an inactive state, it may not receive a response of the subsequence of the re-transmitted MPDU during the same TXOP.

In addition, the VHT station operating in the TXOP power save mode and switched to the inactive state may cause the NAV timer to operate during the inactive state. At this time, for example, when the timer is completed, the VHT station may be switched to an awake state.

In addition, the station may compete for media access when the NAV timer expires.

HE PPDU Format

The frame structure for IEEE802.11ax has not been determined yet, but is expected as follows.

18 illustrates an example of a high efficiency (HE) PPDU format according to an embodiment of the present invention.

11ax maintains the existing 1x symbol structure (3.2us) until the HE-SIG (SIG-A, SIG-B) as shown in the frame structure shown in FIG. 18, and the HE-preamble and Data parts have a 4x symbol (12.8us) structure. You can use a frame structure with Of course, there is no problem in the application of the present invention even if the above-described structure is changed unless directly arranged with the following description.

L-Part can follow the configuration of L-STF, L-LTF, L-SIG as it is maintained in existing WiFi system. In general, the L-SIG preferably transmits packet length information. The HE-Part is a newly constructed part for the 11ax standard (High Efficiency). HE-SIG (HE-SIGA and HE-SIGB) may exist between the L-part and the HE-STF, and may inform common control information and user specific information. Specifically, it may be configured of HE-SIG A for delivering common control information and HE-SIG B for delivering user specific information.

HE-SIGB including user specific information can transmit different information for each 20Mhz channel, but the specific transmission method and structure have not yet been determined. Therefore, the present invention proposes an efficient transmission method of HE-SIG-B including user specific information on the STA.

19 is a diagram for explaining a HE-SIG B configuration in a multi-user PPDU according to one embodiment of the present invention.

First, as described above with reference to FIG. 18, since the HE-SIG B is a field for transmitting user-specific control information, the HE-SIG B may have meaning in a multi-user PPDU.

In 11ax, user-specific information about UE is transmitted through HE-SIG-B. In this case, HE-SIG-B independently transmitted per 20MHz is used for non-intended information to increase efficiency and reduce overhead for HE-SIG-B. (That is, non-user specific information) and intended information (ie, user specific information) may be divided into two parts, and FIG. 19 illustrates this.

In the following description, for convenience, "non-user specific information" is represented by "non-intended" and "user specific information" is represented by "intended".

As shown in FIG. 19, common information of STAs is transmitted through HE-SIG-B Non intended (that is, HE-SIG-B non-user specific), and all STAs for the entire bandwidth in the case of transmitting a signal over a wide bandwidth. It can be configured as a 20MHz channel including the common information of. In the case of broadband transmission, it can be repeatedly transmitted in a 20MHz channel like the transmission of HE-SIG-A.

On the other hand, the HE-SIG-B intended (ie, user specific) information includes specific information on the STA using the corresponding channel for each 20MHz channel and may be configured independently and transmitted in symbol units of the 20MHz channel.

In case of transmitting a signal using the 11ax frame structure as shown in FIG. 19, the number of STAs transmitting and receiving a signal in the BSS and the operation mode (for example, OFDMA, SU / MU-MIMO) of the HE-SIG-B are determined. The structure and content may vary.

For example, when a single STA transmits and receives a signal at 80 MHz, the content of the HE-SIG-B for one STA may be configured as follows. In Table 1 below, the field of HE-SIG-B for SU for configuring one symbol of HE-SIG-B is just one example, and its configuration may be different.

Common SIGB SU SU / MU-MIMO One MCS 4 Start for LTF 0 Coding 2 Nsts 3 STBC One GI 2 SE (Spectral Extend) One Beamformed One (Partial) AID + CRC 9 Tail 6 Sum 23

As described above, since the SU-SIG-B information does not need to be allocated to the HE-SIG-B information, the HE-SIG-B information may be mapped to one symbol at 20 MHz, and may be transmitted using only one symbol. Therefore, in case of SU, HE-SIG-B can transmit using only HE-SIG-B non-intended without dividing HE-SIG-B into two in FIG. 19.

20 is a diagram illustrating an example of a configuration of an HE-SIG B when transmitting a single user PPDU according to an embodiment of the present invention.

That is, FIG. 20 illustrates an example in which the HE-SIG B does not have a user specific field and includes only a common field when the radio frame to be transmitted is a single user PPDU. Meanwhile, as described above, in the case of a single user PPDU, it is also possible to transmit only HE-SIG A without transmitting HE-SIG B itself.

On the other hand, unlike the above, when transmitting and receiving signals for a plurality of STAs using OFDMA at 80 MHz, two HE-SIG-Bs are configured as shown in FIG. 19, and content for each part is configured as shown in the following table. Can be. Table 2 below shows an example of HE-SIG B non-intended field information, and Table 3 shows an example of HE-SIG B intended field information.

Common SIG B Number of per user SIGB symobols (or number of users) 4 SIG B MCS group boundary 12 FE indication 0 Data GI 2 LTE compression factor One Number of LTFs 3 CRC 4 Tail 242 chunk bitmap Sum 26

Per user SIG B OFDMA SU / MU-MIMO One (Partial) AID + CRC 9 Assignment 4 LTF start index 0 Nsts 3 STBC One Coding 2 MCS 4 SE One Beamformed One Tail Sum 26

As described above, the HE-SIG-B for supporting OFDMA may be composed of two parts (non-user specific and user specific), in which case the HE-SIG-B is adjusted by adjusting fields and field bits of the HE-SIG-B. User non-specific information and user specific information of B may be composed of one symbol. Thus, for example, if the HE-SIG-B for four STAs in a 20 MHz channel is assumed to use MCS0, the HE-SIG-B Non-intended 1 symbol and the HE-SIG-B intended 4 symbol may be configured. have.

Meanwhile, when the above-mentioned radio frame supports MU-MIMO, the HE-SIG B may be configured as shown in Tables 4 and 5 below. Tables 4 and 5 below show examples of non-intended and intended fields when MU-MIMO is applied.

Common SIG B Number of per user SIGB symobols (or number of users) 4 SIG B MCS group boundary 12 FE indication (Frame Extend indication) 0 Data GI 2 LTF compression factor One Number of LTFs 3 CRC 4 Tail 242 chunk bitmap Sum 26

Per user SIG B MU-MIMO SU / MU-MIMO One (Partial) AID + CRC 9 Assignment 2 LTF start index 3 Nsts 3 STBC Coding 2 MCS 4 SE One Beamformed Tail Sum 25

As described above, the configuration and contents of the HE-SIG-B may vary according to SU / MU and MU-MIMO. Therefore, in order to indicate configuration information of the HE-SIG-B to the STA, information carried in the HE-SIG-A and the HE-SIG-B may be used in 11ax as follows.

Step 1: The STA receives the HE-SIG-A by transmitting the OFDMA field to the HE-SIG-A through which the common information is transmitted to determine whether the HE-SIG-B is composed of one part or two parts. have. For example, if the OFDMA field of HE-SIG-A is 0, HE-SIG-B is configured only with HE-SIG-B Non intended and if the OFDMA field is 1, HE-SIG-B is HE-SIG You can see that it consists of -B Non intended and HE-SIG-B intended.

Step 2: The STA determines whether HE-SIG-B is configured for single user or multi-user with HE-SIG-A. It is included in the intended purpose of HE-SIG-B. MU-MIMO using SU / MU field It can be determined whether or not to support.

Step 3: The field used to determine the configuration of the HE-SIG-B and whether to support MU-MIMO is one example and may be determined step by step using a field having a different name.

In the above description, in addition to using information included in the HE-SIG-A and the HE-SIG-B step by step, the HE-SIG-A may provide an indication of the PPDU format. In this case, the PPDU format includes 2 bits of information and may indicate SU-PPDU, MU-MIMO PPDU, and OFDMA-PPDU.

Meanwhile, since the number of STAs performing transmission per 20 MHz channel is different, the length of the HE-SIG-B may be different for each 20 MHz. Therefore, in one embodiment of the present invention, in order to match the length of the HE-SIG-B per 20 MHz, the HE-SIG-B can be transmitted using another 20 MHz channel or an adjacent 20 MHz channel in addition to the 20 MHz channel allocated with the resource. Suggest to do. In this case, the following method may be used to inform that the allocation is for a channel other than the corresponding channel.

FIG. 21 illustrates a chunk size of an allocation that an STA can use in a 20 MHz channel according to an embodiment of the present invention.

The information on the resource allocation structure as described above may be transmitted through the common field of the HE-SIG B.

On the other hand, since the 242 chunk is used only for single user transmission in the 20 MHz channel, it is preferable not to use the OFDM when using the OFDMA. Therefore, when transmitting a signal using the OFDMA in the structure, it can indicate that the allocation to other channels by using information indicating 242 chuck of the resource allocation information.

In addition to the above-described method, the adjacent channel indication 1/2 bit may be added to the HE-SIG-B intended to indicate that the allocation is for a channel other than the channel. For example, in the case of transmitting 1 bit, it may be determined whether the allocation information is for a corresponding channel or for an adjacent channel. In this case, since the indication about the allocated channel is not included, when using 1 bit, the information can be used by fixing to the next or previous channel of the channel through which the corresponding information is transmitted. In contrast, in case of using 2 bits, it is possible to indicate which channel the allocation information is for. Thus, STA allocation information can be transmitted through HE-SIG-B of another channel more flexibly than 1 bit. This has the disadvantage of increasing the signaling overhead due to the transmission.

22 is a block diagram illustrating an exemplary configuration of an AP device (or base station device) and a station device (or terminal device) according to an embodiment of the present invention.

The AP 100 may include a processor 110, a memory 120, and a transceiver 130. The station 150 may include a processor 160, a memory 170, and a transceiver 180.

The transceivers 130 and 180 may transmit / receive radio signals and may implement, for example, a physical layer in accordance with the IEEE 802 system. The processors 110 and 160 may be connected to the transceivers 130 and 180 to implement a physical layer and / or a MAC layer according to the IEEE 802 system. Processors 110 and 160 may be configured to perform operations in accordance with one or more combinations of the various embodiments of the invention described above. In addition, the modules for implementing the operations of the AP and the station according to various embodiments of the present invention described above may be stored in the memory 120 and 170, and may be executed by the processors 110 and 160. The memories 120 and 170 may be included in the processors 110 and 160 or may be installed outside the processors 110 and 160 and connected to the processors 110 and 160 by a known means.

The above descriptions of the AP device 100 and the station device 150 may be applied to a base station device and a terminal device in another wireless communication system (eg, LTE / LTE-A system).

The detailed configuration of the AP and the station apparatus as described above, may be implemented to be applied independently or the two or more embodiments described at the same time described in the various embodiments of the present invention, overlapping description is omitted for clarity do.

23 illustrates an exemplary structure of a processor of an AP device or a station device according to an embodiment of the present invention.

The processor of an AP or station may have a plurality of layer structures, and FIG. 29 concentrates on the MAC sublayer 3810 and the physical layer 3820 among these layers, particularly on a Data Link Layer (DLL). Represented by As illustrated in FIG. 29, the PHY 3820 may include a Physical Layer Convergence Procedure (PLCP) entity 3811 and a Physical Medium Dependent (PMD) entity 3822. Both the MAC sublayer 3810 and the PHY 3820 each contain management entities conceptually referred to as a MAC sublayer management entity (MLME) 3811. These entities 3811 and 3821 provide a layer management service interface on which layer management functions operate.

In order to provide correct MAC operation, a Station Management Entity (SME) 3830 exists within each station. SME 3830 is a layer-independent entity that may appear within a separate management plane or appear to be off to the side. Although the precise functions of the SME 3830 are not described in detail herein, in general, this entity 3830 collects layer-dependent states from various Layer Management Entities (LMEs) and values of layer-specific parameters. It can be seen that it is responsible for such functions as setting. SME 3830 can generally perform these functions on behalf of a generic system management entity and implement standard management protocols.

The entities shown in FIG. 23 interact in various ways. Figure 23 shows some examples of exchanging GET / SET primitives. The XX-GET.request primitive is used to request the value of a given MIB attribute (management information based attribute information). The XX-GET.confirm primitive is used to return the appropriate MIB attribute information value if the Status is "Success", otherwise it is used to return an error indication in the Status field. The XX-SET.request primitive is used to request that the indicated MIB attribute be set to a given value. If the MIB attribute means a specific operation, this is to request that the operation be performed. And, the XX-SET.confirm primitive confirms that the indicated MIB attribute is set to the requested value when status is "success", otherwise it is used to return an error condition in the status field. If the MIB attribute means a specific operation, this confirms that the operation has been performed.

As shown in FIG. 23, the MLME 3811 and the SME 3830 can exchange various MLME_GET / SET primitives through the MLME_SAP 3850. In addition, various PLCM_GET / SET primitives can be exchanged between PLME 3821 and SME 3830 via PLME_SAP 3860, and MLME 3811 and PLME 3870 via MLME-PLME_SAP 3870. Can be exchanged between.

Embodiments of the present invention described above may be implemented through various means. For example, embodiments of the present invention may be implemented by hardware, firmware, software, or a combination thereof.

For implementation in hardware, a method according to embodiments of the present invention may include one or more Application Specific Integrated Circuits (ASICs), Digital Signal Processors (DSPs), Digital Signal Processing Devices (DSPDs), and Programmable Logic Devices (PLDs). It may be implemented by field programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, and the like.

In the case of an implementation by firmware or software, the method according to the embodiments of the present invention may be implemented in the form of a module, a procedure, or a function that performs the functions or operations described above. The software code may be stored in a memory unit and driven by a processor. The memory unit may be located inside or outside the processor, and may exchange data with the processor by various known means.

The detailed description of the preferred embodiments of the invention disclosed as described above is provided to enable any person skilled in the art to make and practice the invention. Although the above has been described with reference to the preferred embodiments of the present invention, those skilled in the art will variously modify and change the present invention without departing from the spirit and scope of the invention as set forth in the claims below. I can understand that you can. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein. In addition, while the preferred embodiments of the present specification have been shown and described, the present specification is not limited to the specific embodiments described above, and the technical field to which the present invention belongs without departing from the gist of the present specification claimed in the claims. Of course, various modifications can be made by those skilled in the art, and these modifications should not be individually understood from the technical spirit or prospect of the present specification.

In the present specification, both the object invention and the method invention are described, and the description of both inventions may be supplementarily applied as necessary.

As described above, embodiments of the present invention can be applied to various wireless communication systems, including IEEE 802.11 systems.

Claims (15)

In a method for transmitting an radio frame to one or more stations (STA) in an WLAN system, In the AP, a radio frame including a signaling field and a data field is generated. When the radio frame is a radio frame for transmitting data to a plurality of STAs, The signaling field includes a first signaling field (SIG A field) including first common control information for the plurality of STAs and a second signaling field (SIG B field) including individual control information for each of the plurality of STAs. Including, The second signaling field includes a common field including second common control information for the plurality of STAs, and a separate field subsequent to the common field and including individual control information in each of the plurality of STAs, Transmitting the radio frame to the one or more STAs. The method of claim 1, If the radio frame is a radio frame for transmitting data to one STA, the second signaling field of the radio frame does not include the individual field. The method of claim 1, If the radio frame is a radio frame for transmitting data to one STA, the radio frame does not include the second signaling field. The method of claim 1, The first signaling field includes interpretation information on the second signaling field. The method of claim 1, The common field of the second signaling field is Information on the number of the plurality of STAs, and A radio frame transmission method comprising allocation resource information. The method of claim 1, The individual field of the second signaling field, Identifier information for each of the plurality of STAs, Information about the number of spatial streams, Information on whether to use transmit beamforming, and A radio frame transmission method comprising coding information. The method of claim 1, The second signaling field is configured in units of 20 MHz bands. The method of claim 7, wherein And the signaling field of a specific 20 MHz band includes resource allocation information for a 20 MHz band other than the specific 20 MHz band. The method of claim 8, The resource allocation information is each 20 MHz band A resource structure divided into 26 tons, Resource structure divided into 52 tons, A resource structure divided into 106 tons, and Resource structure divided by 242 tons Allocating resources based on one of the plurality of resource structures, including the radio frame transmission method. The method of claim 1, The radio frame has a form of a Physical Protocol Data Unit (PPDU). An access point (AP) device for transmitting a radio frame to at least one station (STA) in a WLAN system, A processor configured to generate a radio frame comprising a signaling field and a data field; And A transceiver coupled to the processor and configured to transmit the radio frame to the one or more STAs, When the radio frame is a radio frame for transmitting data to a plurality of STAs, The signaling field includes a first signaling field (SIG A field) including first common control information for the plurality of STAs and a second signaling field (SIG B field) including individual control information in each of the plurality of STAs. Including, And wherein the second signaling field includes a common field including second common control information for the plurality of STAs and a separate field including individual control information in each of the plurality of STAs. The method of claim 11, And the processor is configured to not include the individual field in the second signaling field of the radio frame when the radio frame is a radio frame for transmitting data to one STA. The method of claim 11, And the processor is configured to configure the radio frame not to include the second signaling field when the radio frame is a radio frame for transmitting data to one STA. The method of claim 11, The processor configures the second signaling field in units of 20 MHz band. The method of claim 14, And the processor is configured to include resource allocation information for the 20 MHz band other than the specific 20 MHz band in the signaling field of a specific 20 MHz band.

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