WO2016056854A2 - Procédé et terminal de communication sans fil - Google Patents

Procédé et terminal de communication sans fil Download PDF

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Publication number
WO2016056854A2
WO2016056854A2 PCT/KR2015/010639 KR2015010639W WO2016056854A2 WO 2016056854 A2 WO2016056854 A2 WO 2016056854A2 KR 2015010639 W KR2015010639 W KR 2015010639W WO 2016056854 A2 WO2016056854 A2 WO 2016056854A2
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wireless communication
communication terminal
field
sig
communication terminals
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PCT/KR2015/010639
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English (en)
Korean (ko)
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WO2016056854A3 (fr
Inventor
안진수
김용호
곽진삼
손주형
Original Assignee
주식회사 윌러스표준기술연구소
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Publication of WO2016056854A2 publication Critical patent/WO2016056854A2/fr
Publication of WO2016056854A3 publication Critical patent/WO2016056854A3/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W28/00—Network traffic management; Network resource management
    • H04W28/02—Traffic management, e.g. flow control or congestion control
    • H04W28/06—Optimizing the usage of the radio link, e.g. header compression, information sizing, discarding information

Definitions

  • the present invention relates to a wireless communication method and a wireless communication terminal for establishing a broadband link. More specifically, the present invention relates to a wireless communication method and a wireless communication terminal for increasing data communication bandwidth of a terminal to increase data communication efficiency.
  • Wireless LAN technology is a technology that enables wireless devices such as smart phones, smart pads, laptop computers, portable multimedia players, and embedded devices to wirelessly access the Internet at home, enterprise, or specific service area based on wireless communication technology at short range. to be.
  • IEEE 802.11 Since IEEE (Institute of Electrical and Electronics Engineers) 802.11 supports the initial WLAN technology using the 2.4 GHz frequency, various standards of the technology are being put into practice or being developed.
  • IEEE 802.11b supports communication speeds up to 11Mbps while using frequencies in the 2.4GHz band.
  • IEEE 802.11a commercialized after IEEE 802.11b, reduces the impact of interference compared to the frequency of the congested 2.4 GHz band by using the frequency of the 5 GHz band instead of the 2.4 GHz band. Up to 54Mbps.
  • IEEE 802.11a has a shorter communication distance than IEEE 802.11b.
  • IEEE 802.11g like IEEE 802.11b, uses a frequency of 2.4 GHz band to realize a communication speed of up to 54 Mbps and satisfies backward compatibility, which has received considerable attention. Is in the lead.
  • IEEE 802.11n is a technical standard established to overcome the limitation of communication speed, which has been pointed out as a weak point in WLAN. IEEE 802.11n aims to increase the speed and reliability of networks and to extend the operating range of wireless networks. More specifically, IEEE 802.11n supports high throughput (HT) with data throughput of up to 540 Mbps and also uses multiple antennas at both the transmitter and receiver to minimize transmission errors and optimize data rates. It is based on Multiple Inputs and Multiple Outputs (MIMO) technology. In addition, the specification may use a coding scheme that transmits multiple duplicate copies to increase data reliability.
  • MIMO Multiple Inputs and Multiple Outputs
  • IEEE 802.11ac supports a wide bandwidth (80MHz to 160MHz) at 5GHz frequency.
  • the IEEE 802.11ac standard is defined only in the 5GHz band, but for backwards compatibility with existing 2.4GHz band products, early 11ac chipsets will also support operation in the 2.4GHz band. Theoretically, this specification allows multiple stations to have a minimum WLAN speed of 1 Gbps and a maximum single link speed of at least 500 Mbps.
  • IEEE 802.11ad is a method of transmitting data using a 60 GHz band instead of the existing 2.4 GHz / 5 GHz.
  • IEEE 802.11ad is a transmission standard that uses beamforming technology to provide speeds of up to 7Gbps, and is suitable for streaming high bitrate video such as large amounts of data or uncompressed HD video.
  • the 60 GHz frequency band is difficult to pass through obstacles, and thus can be used only between devices in a short space.
  • next generation wireless LAN standard after 802.11ac and 802.11ad, a discussion for providing a high-efficiency and high-performance wireless LAN communication technology in a high-density environment continues. That is, in a next generation WLAN environment, high frequency efficiency communication should be provided indoors / outdoors in the presence of a high density station and an access point (AP), and various technologies are required to implement this.
  • AP access point
  • One embodiment of the present invention is to provide an efficient wireless communication method and a wireless communication terminal.
  • an embodiment of the present invention is to provide a wireless communication method and a wireless communication terminal that any one of the wireless communication terminal to transmit data to a plurality of wireless communication terminal at the same time.
  • Wireless communication terminal includes a transceiver for transmitting and receiving a wireless signal; And a processor configured to control an operation of the wireless communication terminal, wherein the transceiver unit receives a physical frame including data transmitted from a base wireless communication terminal to each of a plurality of wireless communication terminals including the wireless communication terminal,
  • the physical frame includes a first field signaling information commonly applied to the plurality of wireless communication terminals and a second field including information on each of the plurality of wireless communication terminals, wherein the base wireless communication terminal is configured to include the plurality of wireless communication terminals.
  • the wireless communication terminal and any other wireless communication terminal is configured to control an operation of the wireless communication terminal.
  • the first field has a fixed length having a fixed length even with a change in data included in the first field
  • the second field has a variable length
  • the transceiver unit selects the second field based on the first field. Can be received.
  • the first field may include information on a modulation & coding scheme (MCS) of a signal including the second field.
  • MCS modulation & coding scheme
  • the first field may include information indicating the number of orthogonal frequency division multiplexing (OFDM) symbols including the second field.
  • OFDM orthogonal frequency division multiplexing
  • the second field includes resource allocation information indicating a communication medium allocated to each of the plurality of second wireless communication terminals and information on transmission, and the transceiver unit transmits data to the wireless communication terminal based on the resource allocation information. Can be received.
  • the resource allocation information may include information about MCS of a signal including data for the second wireless communication terminal.
  • the resource allocation information includes information indicating a number of space-time streams, information indicating whether convolutional coding has been applied to data for the second wireless communication terminal, and LDCP (Low-) for data for the second wireless communication terminal.
  • density parity-check code may be applied to include at least one of information indicating whether additional OFDM symbols are required.
  • the second field may include a field indicating the resource allocation information for each of the plurality of wireless communication terminals as an independent field.
  • the second field may be transmitted in units of a minimum unit frequency bandwidth, and the minimum unit frequency bandwidth may indicate a minimum bandwidth of a frequency band that can be used by the base terminal.
  • the second field is transmitted through a channel allocated to the wireless communication terminal, and the channel allocated to the wireless communication terminal is smaller than a minimum unit frequency bandwidth, and the minimum unit frequency bandwidth is a frequency band that can be used by the base terminal. It can represent the minimum bandwidth.
  • the data is transmitted through a multi-user Aggregated-MAC Protocol Data Unit (A-MPDU), and the multi-user A-MPDU is transmitted to each of the plurality of wireless communication terminals by the base wireless communication terminal in one A-MPDU. May contain data.
  • A-MPDU Aggregated-MAC Protocol Data Unit
  • a bandwidth of a channel allocated to the wireless communication terminal is smaller than a minimum unit frequency bandwidth, and the transceiver unit transmits a complete frame to the base wireless communication terminal through a channel having a bandwidth equal to or greater than the minimum unit frequency bandwidth, and the minimum unit frequency bandwidth.
  • the transceiver may receive a completion request frame for requesting a completion frame from the base terminal and transmit a completion frame based on the completion request frame.
  • a transceiver for transmitting and receiving a wireless signal; And a processor for controlling an operation of the wireless communication terminal, wherein the transceiver transmits a physical frame including data to be transmitted to each of the plurality of wireless communication terminals to a plurality of wireless communication terminals, and the physical frame is configured to transmit the plurality of physical frames.
  • a method of operating a wireless communication terminal includes a step of receiving a physical frame including data transmitted from the base wireless communication terminal to each of the plurality of wireless communication terminals including the wireless communication terminal, Receiving the physical frame may include receiving a first field signaling information commonly applied to the plurality of wireless communication terminals and receiving a second field including information on each of the plurality of wireless communication terminals.
  • the base wireless communication terminal is any one of wireless communication terminals different from the plurality of wireless communication terminals.
  • One embodiment of the present invention provides an efficient wireless communication method and a wireless communication terminal.
  • an embodiment of the present invention provides a wireless communication method and a wireless communication terminal in which one wireless communication terminal simultaneously transmits data to a plurality of wireless communication terminals.
  • FIG. 1 illustrates a WLAN system according to an embodiment of the present invention.
  • FIG. 2 shows a WLAN system according to another embodiment of the present invention.
  • FIG. 3 is a block diagram showing a configuration of a station according to an embodiment of the present invention.
  • FIG. 4 is a block diagram illustrating a configuration of an access point according to an embodiment of the present invention.
  • FIG. 5 schematically shows a process of establishing a link with an access point by a station according to an embodiment of the present invention.
  • FIG. 6 illustrates a MAC frame header for signaling an A-MSDU transmitted by a wireless communication terminal to a plurality of wireless communication terminals according to an embodiment of the present invention.
  • FIG. 7 illustrates a format of a physical frame including a multi-user A-MPDU transmitted by a wireless communication terminal to a plurality of wireless communication terminals according to an embodiment of the present invention.
  • FIG. 8 illustrates a format of signaling information included in a physical frame transmitted from one wireless communication terminal to a plurality of wireless communication terminals according to an embodiment of the present invention.
  • FIG. 9 illustrates a format of a physical frame including a SIG-B field when a wireless communication terminal transmits a SIG-B field to a plurality of wireless communication terminals in sub-channel units according to an embodiment of the present invention. Shows.
  • FIG. 10 illustrates a format of a physical frame including a SIG-B field when one wireless communication terminal transmits a SIG-B field in a sub-channel unit to a plurality of wireless communication terminals according to an embodiment of the present invention. Shows.
  • FIG. 11 is a view illustrating a format of a physical frame including a SIG-B field when one wireless communication terminal transmits a SIG-B field in sub-channel units to a plurality of wireless communication terminals according to another embodiment of the present invention. Shows.
  • FIG. 12 is a diagram of a physical frame including a SIG-B field when one wireless communication terminal transmits a SIG-B field to a plurality of wireless communication terminals in a minimum unit frequency bandwidth unit according to another embodiment of the present invention. Show the format.
  • FIG. 13 is a diagram of a physical frame including a SIG-B field when one wireless communication terminal transmits a SIG-B field to a plurality of wireless communication terminals in units of minimum frequency bands according to another embodiment of the present invention. Show the format.
  • FIG. 14 illustrates a case in which one wireless communication terminal transmits a SIG-B field to a plurality of wireless communication terminals in sub-channel units, according to an embodiment of the present invention. It shows a change.
  • FIG. 15 illustrates that the length of the SIG-B field depends on the number of OFDM symbols when one wireless communication terminal transmits a SIG-B field to a plurality of wireless communication terminals in sub-channel units. It shows a change.
  • FIG. 16 illustrates a case in which one wireless communication terminal transmits a SIG-B field to a plurality of wireless communication terminals in units of minimum frequency bands, according to another embodiment of the present invention. It shows a change in length.
  • FIG. 17 is a diagram of a SIG-B field according to the number of OFDM symbols when a wireless communication terminal transmits a SIG-B field to a plurality of wireless communication terminals in a minimum unit frequency bandwidth unit according to another embodiment of the present invention. It shows a change in length.
  • FIG. 18 illustrates a case in which one wireless communication terminal transmits a SIG-B field using the entire frequency bandwidth used by one wireless communication terminal to a plurality of wireless communication terminals, according to another embodiment of the present invention. Shows the format of the physical frame containing the B field.
  • FIG. 19 illustrates that an access point transmits data to a plurality of stations and receives an ACK frame, and then transmits an ACK frame through a channel having a bandwidth equal to or greater than the minimum unit frequency bandwidth according to an embodiment of the present invention.
  • FIG. 20 shows that when an access point transmits data to a plurality of stations, each of the plurality of stations transmits an ACK frame through a channel having a bandwidth equal to or greater than the minimum unit frequency bandwidth according to another embodiment of the present invention.
  • FIG. 21 is a view illustrating when an access point transmits data to a plurality of stations according to another embodiment of the present invention, each of the plurality of stations transmits an ACK frame through a channel having a bandwidth greater than or equal to a minimum unit frequency bandwidth, This shows the case where one station fails to transmit an ACK frame.
  • FIG. 22 illustrates that when an access point transmits data to a plurality of stations, each of the plurality of stations transmits an ACK frame through a channel having a bandwidth greater than or equal to a minimum unit frequency bandwidth, This shows the case where one station fails to transmit an ACK frame.
  • FIG. 23 illustrates an ACK frame through a channel having a bandwidth greater than or equal to a minimum unit frequency bandwidth after an access point transmits data to a plurality of stations and receives an ACK frame through a multi-user A-MPDU according to an embodiment of the present invention. Show transmission.
  • FIG. 24 illustrates an access point transmitting data to a plurality of stations through a multi-user A-MPDU according to another embodiment of the present invention, and each of the plurality of stations transmits an ACK frame through a channel having a bandwidth equal to or greater than the minimum unit frequency bandwidth. Show transmission.
  • FIG. 25 illustrates that an access point transmits data to a plurality of stations through a multi-user A-MPDU, and the access point transmits a BAR frame to each of the plurality of stations to induce ACK frame transmission.
  • FIG. 26 is a ladder diagram illustrating operations of a first wireless communication terminal and a second wireless communication terminal according to an embodiment of the present disclosure.
  • the WLAN system includes one or more Basic Service Sets (BSSs), which represent a set of devices that can successfully synchronize and communicate with each other.
  • BSSs Basic Service Sets
  • the BSS may be classified into an infrastructure BSS (Independent BSS) and an Independent BSS (IBSS), and FIG. 1 illustrates an infrastructure BSS.
  • an infrastructure BSS (BSS1, BSS2) is an access point (PCP / AP) that is a station that provides one or more stations (STA1, STA2, STA3, STA4, STA5), and a distribution service.
  • PCP / AP-2 PCP / AP-2
  • DS Distribution System
  • a station is any device that includes a medium access control (MAC) compliant with the IEEE 802.11 standard and a physical layer interface to a wireless medium. This includes both access points (APs) as well as non-AP stations.
  • MAC medium access control
  • APs access points
  • 'terminal' may be used as a concept including both a station and an WLAN communication device such as an AP.
  • the station for wireless communication may include a processor and a transmit / receive unit, and may further include a user interface unit and a display unit according to an embodiment.
  • the processor may generate a frame to be transmitted through the wireless network or process a frame received through the wireless network, and may perform various processing for controlling the station.
  • the transceiver is functionally connected to the processor and transmits and receives a frame through a wireless network for a station.
  • An access point is an entity that provides access to a distribution system (DS) via a wireless medium for an associated station to the AP.
  • DS distribution system
  • the AP is used as a concept including a personal BSS coordination point (PCP), and is broadly used as a centralized controller, a base station (BS), a node-B, a base transceiver system (BTS), or a site. It can include all the concepts such as a controller.
  • PCP personal BSS coordination point
  • BS base station
  • node-B a node-B
  • BTS base transceiver system
  • site can include all the concepts such as a controller.
  • the plurality of infrastructure BSSs may be interconnected through a distribution system (DS).
  • DS distribution system
  • ESS extended service set
  • FIG. 2 illustrates an independent BSS, which is a wireless LAN system according to another embodiment of the present invention.
  • the same or corresponding parts as those of the embodiment of FIG. 1 will be omitted.
  • BSS3 shown in FIG. 2 is an independent BSS and does not include an AP, all stations STA6 and STA7 are not connected to the AP. Independent BSSs do not allow access to the distribution system and form a self-contained network. In the independent BSS, the respective stations STA6 and STA7 may be directly connected to each other.
  • FIG. 3 is a block diagram showing the configuration of a station 100 according to an embodiment of the present invention.
  • the station 100 may include a processor 110, a transceiver 120, a user interface 140, a display unit 150, and a memory 160. .
  • the transceiver 120 transmits and receives a wireless signal such as a wireless LAN packet, may be provided in the station 100 or externally provided.
  • the transceiver 120 may include at least one transceiver module using different frequency bands.
  • the transceiver 120 may include a transceiver module of different frequency bands such as 2.4 GHz, 5 GHz, and 60 GHz.
  • the station 100 may include a transmission / reception module using a frequency band of 6 GHz or more and a transmission / reception module using a frequency band of 6 GHz or less.
  • Each transmit / receive module may perform wireless communication with an AP or an external station according to a wireless LAN standard of a frequency band supported by the corresponding transmit / receive module.
  • the transceiver 120 may operate only one transceiver module at a time or simultaneously operate multiple transceiver modules according to the performance and requirements of the station 100.
  • each transmit / receive module may be provided in an independent form, or a plurality of modules may be integrated into one chip.
  • the user interface unit 140 includes various types of input / output means provided in the station 100. That is, the user interface unit 140 may receive a user input by using various input means, and the processor 110 may control the station 100 based on the received user input. In addition, the user interface 140 may perform an output based on a command of the processor 110 using various output means.
  • the display unit 150 outputs an image on the display screen.
  • the display unit 150 may output various display objects such as contents executed by the processor 110 or a user interface based on a control command of the processor 110.
  • the memory 160 stores a control program used in the station 100 and various data according thereto.
  • a control program may include an access program necessary for the station 100 to perform an access with an AP or an external station.
  • the processor 110 of the present invention may execute various instructions or programs and process data in the station 100.
  • the processor 110 may control each unit of the station 100 described above, and may control data transmission and reception between the units.
  • the processor 110 may execute a program for accessing an AP stored in the memory 160 and receive a communication setup message transmitted by the AP.
  • the processor 110 may read information on the priority condition of the station 100 included in the communication configuration message, and request a connection to the AP based on the information on the priority condition of the station 100.
  • the processor 110 of the present invention may refer to the main control unit of the station 100, and according to an embodiment, a part of the station 100 may be referred to, for example, a control unit for individually controlling the transceiver 120 and the like. You can also point it.
  • the processor 110 controls various operations of the wireless signal transmission and reception of the station 100 according to an embodiment of the present invention. Specific embodiments thereof will be described later.
  • the station 100 illustrated in FIG. 3 is a block diagram according to an embodiment of the present invention, in which blocks marked separately represent logical elements of devices. Therefore, the elements of the above-described device may be mounted in one chip or in a plurality of chips according to the design of the device. For example, the processor 110 and the transceiver 120 may be integrated into one chip or implemented as a separate chip. In addition, in the embodiment of the present invention, some components of the station 100, such as the user interface unit 140 and the display unit 150, may be selectively provided in the station 100.
  • FIG. 4 is a block diagram illustrating a configuration of an AP 200 according to an exemplary embodiment.
  • the AP 200 may include a processor 210, a transceiver 220, and a memory 260.
  • a processor 210 may include a central processing unit (CPU) 210, a graphics processing unit (GPU), and a central processing unit (GPU) 210.
  • a transceiver 220 may include a central processing unit (GPU) 210, and a central processing unit (GPU) 210.
  • a memory 260 may include a processor 210, a transceiver 220, and a memory 260.
  • FIG. 4 overlapping descriptions of parts identical or corresponding to those of the station 100 of FIG. 3 will be omitted.
  • the AP 200 includes a transceiver 220 for operating a BSS in at least one frequency band.
  • the transceiver 220 of the AP 200 may also include a plurality of transceiver modules using different frequency bands. That is, the AP 200 according to the embodiment of the present invention may be provided with two or more transmit / receive modules of different frequency bands, for example, 2.4 GHz, 5 GHz, and 60 GHz.
  • the AP 200 may include a transmission / reception module using a frequency band of 6 GHz or more and a transmission / reception module using a frequency band of 6 GHz or less.
  • Each transmit / receive module may perform wireless communication with a station according to a wireless LAN standard of a frequency band supported by the corresponding transmit / receive module.
  • the transceiver 220 may operate only one transceiver module at a time or simultaneously operate multiple transceiver modules according to the performance and requirements of the AP 200.
  • the memory 260 stores a control program used in the AP 200 and various data according thereto.
  • a control program may include an access program for managing a connection of a station.
  • the processor 210 may control each unit of the AP 200 and may control data transmission and reception between the units.
  • the processor 210 may execute a program for accessing a station stored in the memory 260 and transmit a communication setting message for one or more stations.
  • the communication setting message may include information on the access priority condition of each station.
  • the processor 210 performs connection establishment according to a connection request of a station.
  • the processor 210 controls various operations of wireless signal transmission and reception of the AP 200 according to an embodiment of the present invention. Specific embodiments thereof will be described later.
  • FIG. 5 schematically illustrates a process in which an STA establishes a link with an AP.
  • the scanning step is a step in which the STA 100 obtains access information of a BSS operated by the AP 200.
  • a passive scanning method for obtaining information by using only a beacon message S101 periodically transmitted by the AP 200, and a STA 100 requests a probe to the AP.
  • the STA 100 that has successfully received the radio access information in the scanning step transmits an authentication request (S107a), receives an authentication response from the AP 200 (S107b), and performs an authentication step. do.
  • the STA 100 transmits an association request (S109a), receives an association response from the AP 200 (S109b), and performs the association step.
  • the 802.1X based authentication step S111 and the IP address obtaining step S113 through DHCP may be performed.
  • the authentication server 300 is a server that processes 802.1X-based authentication with the STA 100 and may be physically coupled to the AP 200 or may exist as a separate server.
  • any one wireless communication terminal may simultaneously transmit data to a plurality of wireless communication terminals.
  • any one wireless communication terminal can receive data from a plurality of wireless communication terminals at the same time.
  • An embodiment of the present invention in which one wireless communication terminal transmits data to a plurality of wireless communication terminals will be described with reference to FIG. 6 and subsequent drawings. In particular, it will be described through FIG. 6 and subsequent drawings that a preamble or a MAC header of a signal transmitted by one wireless communication terminal signals a data transmission method for a plurality of wireless communication terminals.
  • the sub-channel is a sub-frequency band included in a channel having a minimum unit frequency bandwidth or more that any one wireless communication terminal can use.
  • the minimum unit frequency bandwidth represents the size of the smallest frequency band that can be used by the first wireless communication terminal. In a specific embodiment, the minimum unit frequency bandwidth may be 20 MHz.
  • any one wireless communication terminal communicating with a plurality of wireless communication terminals at the same time is referred to as a first wireless communication terminal, and a plurality of wireless communication terminals communicating with the first wireless communication terminal simultaneously with a plurality of second wireless terminals.
  • the first wireless communication terminal may also be referred to as a base wireless communication terminal.
  • the first wireless communication terminal may be a wireless communication terminal for allocating and scheduling communication medium resources in communication with the plurality of wireless communication terminals.
  • the first wireless communication terminal may function as a cell coordinator.
  • the first wireless communication terminal may be the access point 200.
  • the second wireless communication terminal may be a station 100 associated with the access point 200.
  • the first wireless communication terminal may be a wireless communication terminal for allocating communication medium resources and scheduling in an independent network that is not connected to an external distribution service such as an ad-hoc network.
  • the first wireless communication terminal may be at least one of a base station, an eNB, and a transmission point (TP).
  • FIG. 6 illustrates a MAC frame header for signaling an A-MSDU transmitted by a wireless communication terminal to a plurality of wireless communication terminals according to an embodiment of the present invention.
  • An Aggregate-Mac Service Data Unit represents a set of MSDUs including a plurality of MSDUs.
  • the first wireless communication terminal may transmit data to the plurality of second wireless communication terminals via the A-MSDU.
  • the first wireless communication terminal may signal resource allocation information for a plurality of second wireless communication terminals that will receive data through a header of the MAC frame including the A-MSDU.
  • the resource allocation information indicates information about a communication medium required for each of the plurality of second wireless communication terminals to communicate with the first wireless communication terminal.
  • each of the plurality of second wireless communication terminals may include at least one of a frequency band allocated for communication with the first wireless communication terminal, a modulation method of a signal, and information about a subcarrier.
  • the header of the MAC frame including the A-MSDU may include addresses representing a plurality of second wireless communication terminals.
  • the Address field of the MAC frame header may indicate an address of each of the plurality of second wireless communication terminals.
  • the first address (Address1) field of the MAC frame header may indicate a second wireless communication terminal to receive data included in the A-MSDU
  • the third address (Address3) field of the MAC frame header indicating the BSSID may be It may indicate any one of a plurality of second wireless communication terminals to receive data included in the A-MSDU other than the BSSID.
  • the fourth address (Address4) field of the MAC frame header indicates data included in the A-MSDU.
  • the first wireless communication terminal may include a first address (Address1) field, a third address (Address3) field, and a fourth address (Address4) of the MAC frame header. It is possible to designate three second wireless communication terminals to receive data through the field).
  • the existing 802.11 standard defines four usage examples of the To DS bit and the From DS bit in the Frame Control field.
  • an additional usage example may be defined in addition to four usage examples of the To DS bit and the From DS bit.
  • the header of the MAC frame may include a field indicating information on control by the number of second wireless communication terminals to receive data.
  • the field indicating the information on the control is a field indicating the information on the sequence control, a field indicating the information on the quality of service (QoS) control, and a field indicating the information on the high throughput (HT) control It may include at least one or more.
  • the header of the MAC frame including the A-MSDU includes a Frame Control field, a Duration / ID field, an Address1 field, an Address2 field, an Address3 field, an Address4 field, a plurality of Sequence Control fields, and a plurality of QoS Control fields. , A plurality of HT Control fields, a Frame Body field, and an FCS field.
  • the Frame Control field represents information about control of a MAC frame.
  • the Duration / ID field represents the duration value of the MAC frame.
  • each of the Address1 field, the Address3 field, and the Address4 field may represent information for identifying each of the plurality of second wireless communication terminals that will receive data included in the A-MSDU.
  • the Address2 field represents information for identifying an address of the first wireless communication terminal that transmits the MAC frame including the A-MSDU.
  • the Sequence Control field is a field representing information on sequence control.
  • the QoS Control field is a field indicating information on quality of service control.
  • the HT Control field is a field indicating information on HT control.
  • the MAC frame header may include the sequence control field, the QoS control field, and the HT control field as many as the number of second wireless communication terminals to receive data through the A-MSDU.
  • the number of second wireless communication terminals to receive data included in the A-MSDU is two. Therefore, the MAC frame header includes two Sequence Control fields, a QoS Control field, and an HT Control field.
  • the Frame Body field contains an A-MSDU.
  • the FCS field indicates whether an error of data included in a MAC frame is included.
  • the first wireless communication terminal When the first wireless communication terminal transmits data to the plurality of second wireless communication terminals, the first wireless communication terminal is assigned to resources allocated to each of the plurality of second wireless communication terminals to the plurality of second wireless communication terminals. Information should be signaled.
  • the first wireless communication terminal may signal information about resources allocated to each of the plurality of second wireless communication terminals by using a preamble of signals transmitted to the plurality of second wireless communication terminals.
  • the information on the resource may be information on frequency, modulation, and coding scheme used by each of the plurality of second wireless communication terminals.
  • the amount of information commonly applied to the plurality of second wireless communication terminals is fixed, but the amount of information applied to each of the plurality of second wireless communication terminals depends on the number of the plurality of second wireless communication terminals.
  • the preamble of the signal transmitted by the first wireless communication terminal to the plurality of second wireless communication terminals includes information commonly applied to the plurality of second wireless communication terminals and information applied to each of the plurality of second wireless communication terminals. can do.
  • a field of a physical frame indicating information commonly applied to a plurality of second wireless communication terminals may be referred to as a SIG-A field.
  • a field of a physical frame indicating information applied to each of the plurality of second wireless communication terminals may be referred to as a SIG-B field.
  • the SIG-A field may have a predetermined length and a predetermined modulation and coding scheme (MCS).
  • MCS modulation and coding scheme
  • the SIG-A field has a fixed length regardless of data included in the SIG-A field and may be transmitted according to a predetermined MCS.
  • the SIG-A field may include control information commonly applied to a plurality of second wireless communication terminals as described above.
  • the SIG-A field includes information about a bandwidth of a channel, a guard interval (GI), a CRC indicating whether an SIG-A field includes an error, and a tail value indicating the termination of a SIG-A field. It may include at least one.
  • the length of the SIG-B field may be variable.
  • the number of OFDM symbols corresponding to the SIG-B field may be variable.
  • the SIG-A field may include at least one of information indicating the MCS of the signal including the SIG-B field and information indicating the number of OFDM symbols including the SIG-B field. It may include any one.
  • the SIG-B field may include information on the plurality of second wireless communication terminals.
  • the information on the plurality of second wireless communication terminals may include information about a communication medium allocated to each of the second wireless communication terminals for communication with the first wireless communication terminal.
  • the SIG-B field may include an identifier for identifying each of the plurality of second wireless communication terminals.
  • the identifier may be a connection identifier for identifying a connection between the first wireless communication terminal and the second wireless communication terminal.
  • the connection identifier may be an association identifier (AID) or a partial AID defined in 802.11.
  • FIG. 7 illustrates a format of a physical frame including a multi-user A-MPDU transmitted by a wireless communication terminal to a plurality of wireless communication terminals according to an embodiment of the present invention.
  • the payload of the physical frame may include a multi-user Aggregation-Mac Protocol Data Unit (A-MPDU).
  • A-MPDU represents an A-MPDU, which is a set of MPDUs including data transmitted from the first wireless communication terminal to each of the plurality of second wireless communication terminals in one A-MPDU.
  • the multi-user A-MPDU may include a first MPDU including data transmitted by the access point to the first station and a second MPDU including data transmitted by the access point to the second station.
  • the SIG-B field signaling the multi-user Aggregation-Mac Protocol Data Unit may include information indicating the MCS of a signal including data transmitted to each of the plurality of second wireless communication terminals.
  • the SIG-B field may include information indicating MCS of the lowest level among MCSs of a signal including data transmitted to each of the plurality of second wireless communication terminals.
  • each of the plurality of second wireless communication terminals may be assigned a sub-channel.
  • the frequency bandwidth of the sub-channel may be smaller than the minimum unit frequency bandwidth.
  • the first wireless communication terminal transmits a SIG-B field for each of the plurality of second wireless communication terminals to each of the plurality of second wireless communication terminals through a frequency band allocated to each of the plurality of second wireless communication terminals.
  • the first wireless communication terminal can transmit the SIG-B field to each of the plurality of second wireless communication terminals through a frequency bandwidth smaller than the minimum unit frequency bandwidth.
  • the payload field of the physical frame may include an A-MPDU.
  • the A-MPDU may be a multi-user A-MPDU.
  • the physical frame includes an L-STF field, an L-LTF field, an L-SIG field, an HE-SIG-A field, an HE-STF field, an HE-LTF field, and an HE-SIG-B field. Include.
  • the L-STF field represents a short training signal that can be decoded by both a wireless communication terminal supporting an embodiment of the present invention and a wireless communication terminal not supporting the embodiment of the present invention.
  • the training signal is a signal that assists in demodulation and decoding setup of a wireless communication terminal for receiving a signal to be transmitted after transmission of the training signal.
  • the short training signal is a training signal having a relatively short signal length.
  • the wireless communication terminal performs automatic gain control (AGC) on an OFDM symbol including an L-LTF field and an L-SIG field based on a short training signal, performs an OFDM symbol and timing and includes an L-SIG field. Frequency can be synchronized.
  • AGC automatic gain control
  • the L-LTF field indicates a long training signal that can be decoded by both a wireless communication terminal supporting an embodiment of the present invention and a wireless communication terminal not supporting the embodiment of the present invention.
  • the long training signal is a training signal having a relatively long signal length.
  • the wireless communication terminal may estimate a fine frequency offset and a channel of an OFDM symbol including an L-SIG field based on the long training signal.
  • the L-SIG field is signaling information that can be decoded by both a wireless communication terminal supporting an embodiment of the present invention and a wireless communication terminal not supporting the embodiment of the present invention.
  • the L-SIG field represents information about a data rate and a data length.
  • the HE-SIG-A field represents information commonly applied to a plurality of second wireless communication terminals.
  • the HE-SIG-A field may be the above-described SIG-A field.
  • the HE-STF field represents a short training signal that can be decoded by a wireless communication terminal supporting an embodiment of the present invention.
  • a wireless communication terminal supporting an embodiment of the present invention provides AGC (Automatic Gain Control) for an OFDM symbol including a HE-LTF field, a HE-SIG-B field, and data included in a payload based on a short training signal. Can be performed.
  • the wireless communication terminal supporting the embodiment of the present invention is based on the short training signal for the timing and frequency of the OFDM symbol including the HE-LTF field, the HE-SIG-B field, and the data contained in the payload Synchronization can be performed.
  • the HE-LTF field represents a long training signal that can be decoded by a wireless communication terminal supporting an embodiment of the present invention.
  • a wireless communication terminal supporting an embodiment of the present invention may estimate a fine frequency offset and a channel of an OFDM symbol including a HE-SIG-B field and data included in a payload based on a long training signal. have.
  • the HE-SIG-B field represents information about a plurality of second wireless communication terminals.
  • the HE-SIG-B field may be the above-described SIG-B field.
  • the first wireless communication terminal divides a channel into four sub-channels and transmits data to four second wireless communication terminals.
  • the first wireless communication terminal transmits a HE-SIG-B field for each of the plurality of second wireless communication terminals through a sub-channel allocated to each of the plurality of second wireless communication terminals.
  • the data may be in the form of an A-MPDU, which is a collection of a plurality of MPDUs.
  • the data may be in the form of multi-user A-MPDU described above.
  • the header of the MPDU may be the same as the MAC frame header defined in the existing 802.11 standard.
  • FIG. 8 illustrates a format of signaling information included in a physical frame transmitted from one wireless communication terminal to a plurality of wireless communication terminals according to an embodiment of the present invention.
  • the preamble of a signal including data transmitted from the first wireless communication terminal to the plurality of second wireless communication terminals may signal information about each of the plurality of second wireless communication terminals.
  • a channel allocated to data reception by each of the second wireless communication terminals may be a sub-channel of a channel used by the first wireless communication terminal.
  • the frequency bandwidth of the sub-channel may be less than the minimum unit frequency bandwidth.
  • the first wireless communication terminal may transmit information about the plurality of second wireless communication terminals in units of the minimum unit frequency bandwidth of the channel.
  • the first wireless communication terminal may classify the preamble into a frequency band having a size of a minimum unit frequency bandwidth.
  • the first wireless communication terminal may divide frequencies of the plurality of second wireless communication terminals. Each band can be transmitted. For example, when the size of the minimum unit frequency bandwidth is 20 MHz and the channel used by the first wireless communication terminal is 20 MHz, the first wireless communication terminal is provided to each of the plurality of second wireless communication terminals through a preamble transmitted through the entire 20 MHz band. Information can be transmitted.
  • the first wireless communication terminal may transmit information on each of the plurality of second wireless communication terminals on a sub-channel basis allocated to each of the plurality of second wireless communication terminals.
  • the bandwidth of the sub-channel may be smaller than the minimum unit frequency bandwidth.
  • the first wireless communication terminal may divide the preamble into a section of the size of the frequency bandwidth of the sub-channel.
  • the first wireless communication terminal may transmit information on each of the plurality of second wireless communication terminals through the sections of the plurality of divided preambles. For example, when each of the four second wireless communication terminals is allocated a sub-channel having a 5 MHz bandwidth, the first wireless communication terminal receives information corresponding to each of the four second wireless communication terminals through a preamble divided into 5 MHz units. Can transmit
  • the minimum unit frequency bandwidth may be 20 MHz.
  • the information about the second wireless communication terminal may include an identifier for identifying the second wireless communication terminal.
  • the identifier may be a group identifier for identifying a group including the second wireless communication terminal.
  • the identifier may also be an association identifier that identifies an association of the second wireless communication terminal and the first wireless communication terminal.
  • the association identifier may be an AID defined in the 802.11 standard.
  • the association identifier may be a partial AID (Partial AID) defined in the 802.11 standard.
  • the information on the second wireless communication terminal may include resource allocation information indicating information on a communication medium and transmission allocated to the second wireless communication terminal.
  • the resource allocation information may include information about MCS of a signal including data transmitted to the second wireless communication terminal.
  • the information on the MCS may be in the form of an MCS field that distinguishes a field for each second wireless communication terminal.
  • the information about the MCS may be in the form of an MCS vector field in which information on MCS of a plurality of signals including data for each of the plurality of second wireless communication terminals is included in one field.
  • the resource allocation information for the second wireless communication terminal may include information indicating the number of space-time streams.
  • the resource allocation information for the second wireless communication terminal may include information indicating whether convolutional coding is applied to data included in the physical frame.
  • the resource allocation information for the second wireless communication terminal may include information indicating whether extra OFDM symbols are required by applying low-density parity-check code (LDCP) coding to data. .
  • LDCP low-density parity-check code
  • the field including information on the plurality of second wireless communication terminals may include a field including resource allocation information for the respective second wireless communication terminal as an independent field.
  • the field including information on the plurality of second wireless communication terminals may include such independent fields as the number of second wireless communication terminals.
  • the independent field may be a field including any one of an individual CRC field and a tail field applied to the corresponding field.
  • the second wireless communication terminal may decode an independent field including information about the second wireless communication terminal and stop decoding the field including the information about the plurality of second wireless communication terminals.
  • the physical frame may include a first field that includes all information about a first station, and may include a second field that includes all information about a second station.
  • the first station may stop decoding the signaling information after acquiring the information corresponding to the first station through the first field. Accordingly, the first station does not decode a field including information on the second station, thereby increasing communication efficiency.
  • the first wireless communication terminal transmits this independent field including information about each of the plurality of second wireless communication terminals to each of the plurality of second wireless communication terminals through a channel assigned to each of the plurality of second wireless communication terminals. Can transmit This will be described later with reference to FIGS. 9 through 11.
  • Such information about the second wireless communication terminal may be included in the SIG-B field as described above.
  • the signaling information included in the physical frame includes a bandwidth field, an STBC field, a plurality of group ID fields, a plurality of number of space-time streams fields, a plurality of partial aid fields, a plurality of coding fields, and a plurality of LDCPs. It may include an extra symbol field and a plurality of MCS fields.
  • the Bandwidth field represents the bandwidth of the channel used by the physical frame.
  • the STBC field indicates whether space-time block coding (STBC) is applied to data included in the payload of the physical frame.
  • STBC space-time block coding
  • the Group ID field identifies a group that contains a second wireless communication terminal to receive the physical frame.
  • the Number of space-time streams field indicates the number of space-time streams.
  • the Partial AID field indicates a partial AID of the second wireless communication terminal that has received the physical frame.
  • the Coding field indicates whether convolutional coding is applied to data included in the physical frame.
  • the LDCP extra symbol field indicates whether extra OFDM symbols are required by applying LDCP coding.
  • the MCS field indicates an MCS of a signal including data corresponding to any one second wireless communication terminal.
  • the MCS field may be replaced with an MCS Vector field.
  • the MCS Vector field represents an MCS of each of a plurality of signals including data transmitted to each of the plurality of second wireless communication terminals as one field.
  • the signaling information included in the physical frame includes a group ID field, a number of space-time streams field, a partial AID field, a plurality of coding fields, an LDCP extra symbol field, and an MCS field as many as a plurality of second wireless communication terminals. can do.
  • the signaling information included in the physical frame may include only one MCS field.
  • the value indicated by the MCS field may be the lowest value among each of the plurality of signals including data for the plurality of second wireless communication terminals.
  • the first wireless communication terminal may transmit resource allocation information for the plurality of second wireless communication terminals in units of the minimum unit frequency bandwidth of the channel. Also, in another specific embodiment, the first wireless communication terminal may transmit information on each of the plurality of second wireless communication terminals on a sub-channel basis allocated to each of the plurality of second wireless communication terminals.
  • the SIG-A field may include all resource allocation information for a plurality of second wireless communication terminals, such as information about a sub-channel.
  • the length of the SIG-A field should be long. Since the wireless communication terminal should be able to decode the signal including the SIG-A field without additional information, the SIG-A field should be encoded according to a fixed MCS. Therefore, it is not preferable that the length of the SIG-A field is longer because the SIG-A field includes all resource allocation information for the plurality of second wireless communication terminals.
  • resource allocation information for the plurality of second wireless communication terminals such as information about the sub-channel, may be included in the SIG-B field.
  • the number of second wireless communication terminals increases, the amount of information included in the SIG-B field increases.
  • the MCS level used by the SIG-B field is high and low, the time required for SIG-B transmission varies.
  • the number of OFDM symbols used for transmission of the SIG-B field is small and large, the air time required for transmission of the SIG-B field varies.
  • the SIG-B field is four times or more than when the first wireless communication terminal transmits data to one second wireless communication terminal. It should include data close to it.
  • the first wireless communication terminal transmits the SIG-B field using 64-FFT as defined in the existing 802.11ax standard, the number of OFDM symbols required for transmitting the SIG-B field of the first wireless communication terminal. Should be increased by four times.
  • the first wireless communication terminal uses 256-FFT for SIG-B field transmission having the same data size, the duration of the OFDM symbol becomes long.
  • the first wireless communication terminal must variably select the MCS used for transmission of the SIG-B field.
  • the first wireless communication terminal may determine the MCS level used for SIG-B transmission according to the MCS level of the second wireless communication terminal requiring the lowest MCS level among the plurality of second wireless communication terminals. Through this, the first wireless communication terminal can achieve stability of the SIG-B transmission.
  • the first wireless communication terminal may determine the MCS level such that the number of OFDM symbols in the SIG-B field is one or more.
  • the first wireless communication terminal may determine the MCS level of the SIG-B field so that the number of OFDM symbols of the SIG-B field is an integer number according to the data amount of the SIG-B field.
  • the SIG-A field may include information indicating the MCS used for transmission of the SIG-B field.
  • the SIG-A field may include information indicating the number of OFDM symbols required for transmission of the SIG-B field.
  • the first wireless communication terminal may transmit the SIG-B field in sub-channel units allocated to each of the plurality of second wireless communication terminals. 9 to 11, it is described that the first wireless communication terminal transmits the SIG-B field in sub-channel units allocated to each of the plurality of second wireless communication terminals.
  • 9 to 10 illustrate a format of a physical frame transmitted by one wireless communication terminal to a plurality of wireless communication terminals according to an embodiment of the present invention.
  • the first wireless communication terminal may transmit a SIG-B field to each of the plurality of second wireless communication terminals by using a preamble transmitted through a channel allocated to each of the plurality of second wireless communication terminals.
  • the first wireless communication terminal may transmit a SIG-B field corresponding to each of the plurality of second wireless communication terminals through a channel allocated to each of the plurality of second wireless communication terminals.
  • the first wireless communication terminal may transmit a training signal for demodulation and decoding setting of the second wireless communication terminal for receiving a signal including the SIG-B field and data prior to transmitting the SIG-B field.
  • the first wireless communication terminal may transmit an STF field indicating a short training signal and an LTF field indicating a long training signal prior to transmitting the SIG-B field.
  • the second wireless communication terminal performs AGC (Automatic Gain Control) on the OFDM symbol including the LTF field, the SIG-B field, and the data based on the short training signal, and performs a timing and frequency of the OFDM symbol including the data. Synchronization can be performed.
  • the second wireless communication terminal may estimate at least one of a fine frequency offset and a channel of the OFDM symbol including the SIG-B field and data based on the long training signal.
  • the first wireless communication terminal transmits at least one of information on the MCS of the signal including the SIG-B field and information indicating the number of OFDM symbols in the SIG-B field through the SIG-A field.
  • the SIG-A field may include information regarding the MCS of the signal including the SIG-B field in the form of a plurality of MCS fields.
  • the MCS field represents an MCS of a signal transmitted through an individual sub-channel.
  • the SIG-A field may include as many MCS fields as the number of sub-channels used by the plurality of second wireless communication terminals.
  • the SIG-A field may include information on MCS of a signal including the SIG-B field in the form of an MCS vector field.
  • the MCS vector field indicates the MCS of the plurality of sub-channels assigned to the plurality of second wireless communication terminals through one field.
  • the MCS vector field may indicate MCS of a plurality of sub-channels allocated to a plurality of second wireless communication terminals through an index.
  • the index may represent the number of all MCS combinations that the plurality of sub-channels allocated to the plurality of second wireless communication terminals may have.
  • the number of sub-channels that can be used by the plurality of second wireless communication terminals in the minimum unit frequency band is maximum 4, and the number of bits required to represent one MCS may be 4 bits.
  • the plurality of MCS fields require a total of 16 bits.
  • the MCS vector field since the MCS vector field must represent a total of 10,000 cases, the MCS vector field requires 14 bits.
  • the second wireless communication terminal receives the SIG-B field based on the SIG-A field.
  • the second wireless communication terminal may obtain at least one of information on the MCS of the signal including the SIG-B field and information indicating the number of symbols in the SIG-B field from the SIG-A field.
  • the second wireless communication terminal determines the first radio field in the SIG-B field based on at least one of information on the MCS of the signal including the acquired SIG-B field and information indicating the number of OFDM symbols in the SIG-B field. It can receive from a communication terminal.
  • the SIG-B field may include information about a plurality of second wireless communication terminals.
  • the information about the plurality of second wireless communication terminals may include information about an identifier for identifying each of the plurality of second wireless communication terminals as described above.
  • the information about the plurality of second wireless communication terminals may include resource allocation information as described above.
  • the SIG-B field may include information about MCS of a signal including data transmitted to each of the plurality of second wireless communication terminals.
  • the second wireless communication terminal can receive data based on the SIG-B field.
  • the second wireless communication terminal may obtain information about the plurality of second wireless communication terminals from the SIG-B field.
  • the second wireless communication terminal may receive data from the first wireless communication terminal based on the obtained information about the plurality of second wireless communication terminals.
  • the SIG-B field has a variable length and does not use a predetermined MCS for transmission of the SIG-B field. Therefore, the transmission time of the SIG-B field varies according to the MCS determined by the first wireless communication terminal as the MCS of the signal including the SIG-B field.
  • FIG. 10 shows that when the MCS level of the signal including the SIG-B field is relatively high, the air time of the SIG-B field is shortened.
  • the first wireless communication terminal may determine the MCS level such that the number of OFDM symbols in the SIG-B field is one or more. In addition, the first wireless communication terminal may determine the MCS level of the SIG-B field so that the number of OFDM symbols of the SIG-B field is an integer number according to the data amount of the SIG-B field.
  • the first wireless communication terminal may use the same MCS for a plurality of signals including each of the plurality of SIG-B fields for each of the plurality of second wireless communication terminals.
  • the first wireless communication terminal may determine the MCS level used for SIG-B transmission according to the MCS level of the second wireless communication terminal requiring the lowest MCS level among the plurality of second wireless communication terminals.
  • 11 is a view illustrating a format of a physical frame transmitted by one wireless communication terminal to a plurality of wireless communication terminals according to another embodiment of the present invention.
  • the first wireless communication terminal may transmit each of the plurality of SIG-B fields for each of the plurality of second wireless communication terminals using different MCSs. Specifically, the first wireless communication terminal determines the MCS used to transmit each of the plurality of SIG-B fields for each of the plurality of second wireless communication terminals according to the MCS level each of the plurality of second wireless communication terminals can receive. Can be. Accordingly, the transmission time of each of the plurality of SIG-B fields for each of the plurality of second wireless communication terminals may be different. In addition, the first wireless communication terminal can allocate more OFDM symbols for data transmission by reducing the transmission time of the SIG-B field.
  • the first wireless communication terminal transmits the SIG-B fields for the first station STA1 and the second station STA3 using the same MCS.
  • the first wireless communication terminal has a level lower than that of the MCS used in the SIG-B fields for the first station STA1 and the second station STA3 for the SIG-B field for the fourth station STA4.
  • Send using MCS MCS.
  • the first wireless communication terminal has a level higher than that of the MCS used for the SIG-B fields for the first station STA1 and the second station STA3 for the SIG-B field for the fourth station STA4.
  • the transmission time of the SIG-B field for the second station STA2 is shortest, and the transmission time of the SIG-B field for the fourth station STA4 is longest.
  • the first wireless communication terminal may transmit the SIG-B field in units of the minimum unit frequency bandwidth. This will be described with reference to FIGS. 12 to 13.
  • 12 to 13 illustrate a case in which one wireless communication terminal transmits a SIG-B field to a plurality of wireless communication terminals in a minimum unit frequency bandwidth unit, according to another embodiment of the present invention. Shows the format of the physical frame.
  • the first wireless communication terminal may modulate and transmit the SIG-B field by Fourier transform having the same coefficient as the SIG-A field.
  • the first wireless communication terminal may modulate and transmit the SIG-B field and the SIG-A field by 64 FFT. In this case, since the Fourier transform coefficients of the SIG-B field and the SIG-A field are the same, no separate training signal is required.
  • the first wireless communication terminal may modulate and transmit the SIG-B field by Fourier transform having a coefficient different from that of the SIG-A field. In this case, the first wireless communication terminal may not transmit a separate training signal for the SIG-B field for signal transmission efficiency. In this case, the first wireless communication terminal may modulate and transmit the SIG-B field to one of 128 FFT and 256 FFT.
  • the first wireless communication terminal After transmitting the SIG-B field, the first wireless communication terminal transmits a short training signal and a long training signal for data transmission for each of the plurality of second wireless communication terminals.
  • the short training signal may be the above-described HE-STF.
  • the long training signal may be the above-described HE-LTF.
  • FIG. 13 shows that when the MCS level of the signal including the SIG-B field is relatively high, the air time of the SIG-B field is shortened.
  • the first wireless communication terminal may signal the MCS of the SIG-B field through the SIG-A.
  • the second wireless communication terminal may receive the SIG-B field based on the SIG-A.
  • information about MCS of the SIG-B field may be obtained from the SIG-A field, and the SIG-B field may be received based on the obtained information about MCS of the SIG-B field.
  • the amount of data included in the SIG-B field may vary. Therefore, even when the first wireless communication terminal modulates using the same MCS, the number of OFDM symbols including the SIG-B field may vary. In addition, when the size of the frequency band to which the SIG-B field is transmitted varies, even when modulating using the same MCS, the number of OFDM symbols including the SIG-B field may vary. Therefore, the first wireless communication terminal must signal the number of OFDM symbols including the SIG-B field through the SIG-A field. This will be described with reference to FIGS. 14 to 17.
  • FIGS. 14 to 15 are diagrams illustrating a SIG-B field according to the number of OFDM symbols when one wireless communication terminal transmits a SIG-B field in sub-channel units to a plurality of wireless communication terminals according to an embodiment of the present invention. Shows that the length of the is changed.
  • 16 to 17 illustrate when a wireless communication terminal transmits a SIG-B field in units of minimum frequency bands to a plurality of wireless communication terminals according to another embodiment of the present invention, according to the number of OFDM symbols. It shows that the length of the SIG-B field is changed.
  • the first wireless communication terminal may transmit a SIG-A field signaling the number of OFDM symbols including the SIG-B field.
  • the second wireless communication terminal may receive the SIG-B field based on the SIG-A field.
  • the second wireless communication terminal can obtain information indicating the number of OFDM symbols including the SIG-B field from the SIG-A field.
  • the second wireless communication terminal may receive the SIG-B field based on information indicating the number of OFDM symbols including the SIG-B field.
  • the number of OFDM symbols including the SIG-B field signaled by the SIG-A field may be an integer number.
  • the number of OFDM symbols including the SIG-B field signaled by the SIG-A field may be one.
  • the number of OFDM symbols including the SIG-B field signaled by the SIG-A field may be zero.
  • the first wireless communication terminal and the second wireless communication terminal communicate with each other without using the SIG-B field.
  • FIG. 14 illustrates a case where the number of OFDM symbols including the SIG-B field is relatively large.
  • FIG. 15 shows a case where the number of OFDM symbols including the SIG-B field is relatively small.
  • FIG. 16 shows a relatively large number of OFDM symbols including a SIG-B field.
  • FIG. 17 illustrates a case where the number of OFDM symbols including the SIG-B field is relatively small.
  • the first wireless communication terminal may repeatedly transmit the same SIG-A field to the plurality of second wireless communication terminals in units of the minimum unit frequency bandwidth.
  • the SIG-B field should include more data than the SIG-A field. Therefore, it is inefficient for the first wireless communication terminal to transmit the same SIG-A field to the plurality of second wireless communication terminals repeatedly in the minimum unit frequency bandwidth unit. Therefore, when the first wireless communication terminal uses a frequency bandwidth of more than the minimum unit frequency bandwidth, there is a need for a method in which the first wireless communication terminal can efficiently transmit the SIG-B field to the plurality of second wireless communication terminals.
  • FIG. 18 illustrates a case in which one wireless communication terminal transmits a SIG-B field using the entire frequency bandwidth used by one wireless communication terminal to a plurality of wireless communication terminals, according to another embodiment of the present invention. Shows the format of the physical frame containing the B field.
  • the first wireless communication terminal may transmit the SIG-B field to the plurality of second wireless communication terminals through a frequency band having a bandwidth equal to or greater than the minimum unit frequency bandwidth.
  • the first wireless communication terminal may transmit the SIG-B field to the plurality of second wireless communication terminals in units of the minimum unit frequency bandwidth.
  • the first wireless communication terminal may transmit the SIG-B field by dividing the minimum unit frequency bandwidth.
  • the first wireless communication terminal uses a frequency band having a bandwidth of 40 MHz.
  • the minimum frequency unit bandwidth is 20 MHz.
  • the first wireless communication terminal transmits data to four second wireless communication terminals through a 20MHz bandwidth.
  • the first wireless communication terminal transmits data to the other four second wireless communication terminal through the remaining 20MHz bandwidth.
  • the first wireless communication terminal transmits the SIG-B field signaling the information about the four second wireless communication terminals in the 20 MHz frequency band, and the SIG- signaling the information about the remaining four second wireless communication terminals.
  • the B field may be transmitted in the remaining 20 MHz frequency band.
  • the second wireless communication terminal may receive the SIG-B field in units of the minimum unit frequency bandwidth.
  • the second wireless communication terminal can check whether information about the second wireless communication terminal is included in the SIG-B field corresponding to the minimum frequency unit bandwidth. If the information on the second wireless communication terminal is not included, the second wireless communication terminal may check whether the information on the second wireless communication terminal is included in the SIG-B field corresponding to the next minimum frequency unit bandwidth.
  • the first wireless communication terminal can efficiently transmit the SIG-B field including relatively more data than the SIG-A.
  • the first wireless communication terminal may transmit data through the sub-channel to each of the plurality of second wireless communication terminals.
  • the sub-channel may be a frequency band having a bandwidth smaller than the minimum unit frequency bandwidth as in the above-described embodiments.
  • the wireless communication terminal that does not support the embodiment of the present invention may receive only a frame transmitted over a band of the minimum unit frequency bandwidth or more.
  • the wireless communication terminal that does not support the embodiment of the present invention may receive the control frame transmitted through the sub-channel. none. Therefore, a wireless communication terminal that does not support an embodiment of the present invention cannot obtain information about communication between a first wireless communication terminal and a plurality of second wireless communication terminals that are displayed through a control frame. As a result, a problem may occur in which a wireless communication terminal that does not support the embodiment of the present invention cannot clearly determine whether the communication between the first wireless communication terminal and the plurality of second wireless communication terminals is continued and completed.
  • the first wireless communication terminal and the second wireless communication terminal may control the control frame through a channel having a bandwidth equal to or greater than the minimum unit frequency bandwidth. Can transmit This will be described with reference to FIGS. 19 to 25.
  • FIG. 19 illustrates that an access point transmits data to a plurality of stations and receives an ACK frame, and then transmits an ACK frame through a channel having a bandwidth equal to or greater than the minimum unit frequency bandwidth according to an embodiment of the present invention.
  • the first wireless communication terminal and the plurality of second wireless communication terminals transmit a control frame to control transmission of data for the plurality of second wireless communication terminals of the first wireless communication terminal.
  • control frame represents a frame for controlling the communication operation between the first wireless communication terminal and the second wireless communication terminal.
  • control frame may include a Request to Send (RTS) frame, a Clear to Send (CTS) frame, an ACK frame, a Block ACK (BA) frame, a Block ACK Request (BAR) frame, and a PS-Poll frame.
  • RTS Request to Send
  • CTS Clear to Send
  • ACK ACK
  • BA Block ACK
  • BAR Block ACK Request
  • the first wireless communication terminal and the second wireless communication terminal may transmit the control frame through a channel having a bandwidth equal to or greater than the minimum unit frequency bandwidth.
  • the first wireless communication terminal receives data from the second wireless communication terminal.
  • the second wireless communication terminal transmits a completion frame, which is a frame indicating completion of data reception, to the first wireless communication terminal.
  • the complete frame may be an ACK frame or a BA frame.
  • the second wireless communication terminal may transmit a complete frame through the corresponding sub-channel. In this case, as described above, the wireless communication terminal that does not support the embodiment of the present invention cannot receive the completion frame.
  • a wireless communication terminal that does not support an embodiment of the present invention cannot clearly know whether data transmission is terminated in a corresponding channel.
  • the first wireless communication terminal may receive a complete frame from the plurality of second wireless communication terminals, and then transmit the complete frame through a channel having a bandwidth equal to or greater than the minimum unit frequency bandwidth.
  • the reception address of the completion frame may represent the first wireless communication terminal.
  • the channel having a bandwidth greater than or equal to the minimum unit frequency bandwidth may be obtained by dividing the entire channel used by the first wireless communication terminal by the minimum unit frequency bandwidth.
  • the access point (AP) uses a channel of 20MHz.
  • the access point AP transmits data to the first station STA1, the second station STA2, the third station STA3, and the fourth station STA4 through each of four sub-channels having a bandwidth of 5 MHz. send.
  • the access point AP transmits data to the first station STA1 through a first sub-channel # 1.
  • the access point AP transmits data to the second station STA2 through a second sub-channel # 2.
  • the access point AP transmits data to the third station STA3 through a third sub-channel # 3.
  • the access point AP transmits data to the fourth station STA4 through the fourth sub-channel # 4.
  • the first station STA1, the second station STA2, the third station STA3, and the fourth station STA4 are each connected through four sub-channels having a bandwidth of 5 MHz.
  • the first station STA1 transmits an ACK frame to the access point AP through the first sub-channel # 1.
  • the second station STA2 transmits an ACK frame to the access point AP through the second sub-channel # 2.
  • the third station STA3 transmits an ACK frame to the access point AP through the third sub-channel # 3.
  • the fourth station STA4 transmits an ACK frame to the access point AP through the fourth sub-channel # 4.
  • the predetermined time may be a short inter-frame space (SIFS) defined in the 802.11 standard.
  • SIFS short inter-frame space
  • the access point (AP) transmits an ACK frame on a channel having a 20MHz bandwidth.
  • wireless communication terminals other than the access point AP and the first station STA1 to the fourth station STA4 may also transmit data between the access point AP and the first station STA1 to the fourth station STA4. You can see that it is complete.
  • the plurality of second wireless communication terminals may sequentially transmit frames indicating completion of data transmission through a channel having a bandwidth equal to or greater than the minimum unit frequency bandwidth. In this case, it may take more time to transmit a frame indicating completion of data transmission than the embodiment described in the embodiment of FIG. 19. However, in this embodiment, since the control frame is not transmitted through a frequency band having a bandwidth less than the minimum unit bandwidth, the compatibility with the wireless communication terminal that does not support the embodiment of the present invention may be further increased. This will be described with reference to FIGS. 20 to 22.
  • FIG. 20 shows that when an access point transmits data to a plurality of stations, each of the plurality of stations transmits an ACK frame through a channel having a bandwidth equal to or greater than the minimum unit frequency bandwidth according to another embodiment of the present invention.
  • Each of the plurality of second wireless communication terminals that receive data from the first wireless communication terminal may transmit a complete frame to the first wireless communication terminal through a channel having a bandwidth equal to or greater than the minimum unit frequency bandwidth.
  • the plurality of second wireless communication terminals may sequentially transmit the complete frame to the first wireless communication terminal through a channel having a bandwidth equal to or greater than the minimum unit frequency bandwidth.
  • the complete frame may be transmitted to the first wireless communication terminal in order from the second wireless communication terminal assigned the low frequency band to the second wireless communication terminal assigned the high frequency band.
  • the complete frame may be transmitted to the first wireless communication terminal in order from the second wireless communication terminal allocated with the high frequency band to the second wireless communication terminal allocated with the low frequency band.
  • the access point (AP) uses a channel of 20 MHz.
  • the access point AP transmits data to the first station STA1, the second station STA2, the third station STA3, and the fourth station STA4 through each of four sub-channels having a bandwidth of 5 MHz. send.
  • the access point AP transmits data to the first station STA1 through a first sub-channel # 1.
  • the access point AP transmits data to the second station STA2 through a second sub-channel # 2.
  • the access point AP transmits data to the third station STA3 through a third sub-channel # 3.
  • the access point AP transmits data to the fourth station STA4 through the fourth sub-channel # 4.
  • the first station STA1 transmits an ACK frame to the access point AP through a channel having a bandwidth of 20 MHz. Specifically, after SIFS from when data is transmitted, the first station STA1 transmits an ACK frame to the access point AP through a channel having a bandwidth of 20 MHz.
  • the second station STA2 After the first station STA1 transmits the ACK frame, the second station STA2 transmits the ACK frame to the access point AP through a channel having a bandwidth of 20 MHz. Specifically, after SIFS from when the first station STA1 transmits the ACK frame, the second station STA2 transmits the ACK frame to the access point AP through a channel having a bandwidth of 20 MHz.
  • the third station STA3 transmits the ACK frame to the access point AP through a channel having a bandwidth of 20 MHz. Specifically, after SIFS from when the second station STA2 transmits the ACK frame, the third station STA3 transmits the ACK frame to the access point AP through a channel having a bandwidth of 20 MHz.
  • the fourth station STA4 transmits the ACK frame to the access point AP through a channel having a bandwidth of 20 MHz. Specifically, after SIFS from when the third station STA3 transmits the ACK frame, the fourth station STA4 transmits the ACK frame to the access point AP through a channel having a bandwidth of 20 MHz.
  • a complete frame transmitted by one of the plurality of second wireless communication terminals may collide with a frame transmitted by the wireless communication terminal included in the other BSS.
  • the complete frame transmitted by any one of the plurality of second wireless communication terminals is not transmitted to the first wireless communication terminal. Therefore, there is a need for a method to compensate for this problem. This will be described with reference to FIGS. 21 to 22.
  • 21 to 22 illustrate that when an access point transmits data to a plurality of stations according to another embodiment of the present invention, each of the plurality of stations transmits an ACK frame and transmits an ACK frame through a channel having a bandwidth equal to or greater than the minimum unit frequency bandwidth. Shows a case in which one of the stations of the station does not transmit the ACK frame.
  • the first wireless communication terminal may transmit a completion request frame to a second wireless communication terminal that has not transmitted the completion frame among the plurality of second wireless communication terminals from which the first wireless communication terminal transmits data.
  • the completion request frame is a frame for requesting the transmission of the completion frame.
  • the completion request frame may be a BAR frame.
  • the first wireless communication terminal may transmit the completion request frame to the corresponding second wireless communication terminal.
  • the access point AP is a first station STA1, a second station STA2, a third station STA3, and a fourth through each of four sub-channels having a bandwidth of 5 MHz.
  • the access point AP transmits data to the first station STA1 through a first sub-channel # 1.
  • the access point AP transmits data to the second station STA2 through a second sub-channel # 2.
  • the access point AP transmits data to the third station STA3 through a third sub-channel # 3.
  • the access point AP transmits data to the fourth station STA4 through the fourth sub-channel # 4.
  • the first station STA1 to the second station STA2 sequentially transmit ACK frames to the access point AP.
  • the third station STA3 transmits an ACK frame to the access point AP.
  • the ACK frame transmitted by the third station STA3 may not be transmitted to the AP due to a collision with a frame transmitted by another wireless communication terminal.
  • the access point AP transmits a BAR frame to the third station STA3.
  • the third station STA3 retransmits the ACK frame to the access point AP.
  • the fourth station STA4 sequentially transmits the ACK frame to the access point AP.
  • another second wireless communication terminal may not confirm that the completion frame of one second wireless communication terminal is not transmitted to the first wireless communication terminal. Therefore, when the first wireless communication terminal transmits the completion request frame, another second wireless communication terminal may transmit the completion frame to the first wireless communication terminal. Therefore, in order to prevent this, the first wireless communication terminal ends the transmission of the completion frame of the second wireless communication terminals other than the second wireless communication terminal which failed to transmit the completion frame among the plurality of second wireless communication terminals, and completes the request frame. Can be transmitted.
  • the access point AP is configured to transmit the first station STA1, the second station STA2, and the first station through each of four sub-channels having a bandwidth of 5 MHz, as in the embodiment of FIG. 21.
  • Data is transmitted to the third station STA3 and the fourth station STA4.
  • the access point AP transmits data to the first station STA1 through a first sub-channel # 1.
  • the access point AP transmits data to the second station STA2 through a second sub-channel # 2.
  • the access point AP transmits data to the third station STA3 through a third sub-channel # 3.
  • the access point AP transmits data to the fourth station STA4 through the fourth sub-channel # 4.
  • the first station STA1 to the second station STA2 sequentially transmit ACK frames to the access point AP.
  • the third station STA3 sequentially transmits the ACK frame to the access point AP.
  • the ACK frame transmitted by the third station STA3 may not be transmitted to the AP due to a collision with a frame transmitted by another wireless communication terminal.
  • the fourth station STA4 sequentially transmits the ACK frame to the access point AP.
  • the access point AP After receiving the ACK frame transmitted by the fourth station STA4, the access point AP transmits a BAR frame to the third station STA3.
  • the third station STA3 retransmits the ACK frame to the access point AP.
  • the first wireless communication terminal may transmit data to the plurality of second wireless communication terminals through the multi-user A-MPDU.
  • two second wireless communication terminals receive data through one sub-channel, there is a need for a method of transmitting a complete frame of a second wireless communication terminal different from the previously described embodiments. This will be described with reference to FIGS. 23 to 25.
  • FIG. 23 illustrates an ACK frame through a channel having a bandwidth greater than or equal to a minimum unit frequency bandwidth after an access point transmits data to a plurality of stations and receives an ACK frame through a multi-user A-MPDU according to an embodiment of the present invention. Show transmission.
  • the second wireless communication terminal may transmit the completion frame through the corresponding sub-channel.
  • the plurality of second wireless communication terminals that receive data through the multi-user A-MPDU may sequentially transmit a complete frame to the first wireless communication terminal through sub-channels allocated to the plurality of second wireless communication terminals.
  • the plurality of second wireless communication terminals that receive data through the multi-user A-MPDU are identifiers indicating the plurality of second wireless communication terminals in a preamble or a header including information on the plurality of second wireless communication terminals.
  • Complete frames may be sequentially transmitted to the first wireless communication terminal based on the sorting order of.
  • the plurality of second wireless communication terminals that receive data through the multi-user A-MPDU may arrange the identifiers indicating the plurality of second wireless communication terminals in a preamble or header including information about the plurality of second wireless communication terminals.
  • the complete frames may be sequentially transmitted to the first wireless communication terminal in order.
  • the plurality of second wireless communication terminals that have received data through the multi-user A-MPDU may have an identifier sort order indicating the plurality of second wireless communication terminals in a preamble or header including information on the plurality of second wireless communication terminals.
  • the complete frame may be transmitted to the first wireless communication terminal in reverse order.
  • the plurality of second wireless communication terminals that receive data through the multi-user A-MPDU sequentially transmit the completion frame to the first wireless communication terminal based on the data sorting order included in the multi-user A-MPDU.
  • Can transmit For example, if the multi-user A-MPDU includes data for the first station and data for the second station in order, the first station and the second station are sent by the first station first to send a complete frame and later to a second frame. This complete frame can be transmitted to the first wireless communication terminal.
  • the plurality of second wireless communication terminals that receive data through the multi-user A-MPDU may determine the MCS level of the signal used for data transmission to each second wireless communication terminal in the multi-user A-MPDU.
  • Complete frames may be sequentially transmitted to the first wireless communication terminal based on the size.
  • the plurality of second wireless communication terminals that have received data through the multi-user A-MPDUs have an order in which the magnitude of the MCS level of the signal used for data transmission for each second wireless communication terminal in the multi-user A-MPDU is large. As a result, the complete frame may be transmitted to the first wireless communication terminal.
  • the plurality of second wireless communication terminals that have received data through the multi-user A-MPDUs have a smaller MCS level order of the signals used for data transmission for each second wireless communication terminal in the multi-user A-MPDU.
  • the complete frame may be transmitted to the first wireless communication terminal.
  • the plurality of second wireless communication terminals that receive data through the multi-user A-MPDU are based on a value indicating a traffic priority of a frame for each second wireless communication terminal in the multi-user A-MPDU.
  • the complete frame may be sequentially transmitted to the first wireless communication terminal.
  • the plurality of second wireless communication terminals that receive data through the multi-user A-MPDUs are arranged in order of increasing magnitude of the traffic priority of the frame for each second wireless communication terminal in the multi-user A-MPDU.
  • the complete frame may be transmitted to the first wireless communication terminal.
  • the plurality of second wireless communication terminals that receive data through the multi-user A-MPDUs may be arranged in order of decreasing value of the traffic priority of the frame for each second wireless communication terminal in the multi-user A-MPDU.
  • the complete frame may be transmitted to the first wireless communication terminal.
  • the value representing the traffic priority may be an access category in enhanced distributed channel access (EDCA).
  • the plurality of second wireless communication terminals that receive data through the multi-user A-MPDU sequentially transmit the complete frame to the first wireless communication terminal based on a separate frame or field indicating the transmission order of the completed frames. Can be sent.
  • each of the plurality of second wireless communication terminals that have received data through the multi-user A-MPDU may use the first wireless communication terminal based on a time required for transmitting a complete frame after receiving the multi-user A-MPDU and its own transmission order.
  • the complete frame can be sent to the.
  • each of the plurality of second wireless communication terminals that receive data through the multi-user A-MPDU may transmit a completion frame to the first wireless communication terminal after the time required by the following equation.
  • t represents a time when the second wireless communication terminal transmits a complete frame
  • inter_frame_time represents the time to wait after one complete frame transmission
  • N represents the completion frame transmission order of the second wireless communication terminal
  • ACK_transmission_time It shows the time required for the transmission of the complete frame.
  • the waiting time after the completion frame transmission may be SIFS.
  • the first wireless communication terminal may receive the complete frame from the plurality of second wireless communication terminals, and then transmit the complete frame through a channel having a bandwidth equal to or greater than the minimum unit frequency bandwidth.
  • the access point AP is a first station STA1, a second station STA2, a third station STA3, and a fourth station through each of four sub-channels having a bandwidth of 5 MHz. STA4 and data to a fifth station STA5.
  • the access point AP transmits a multi-user A-MPDU to the first station STA1 and the second station STA2 through a first sub-channel # 1.
  • the access point AP transmits data to the third station STA3 through the second sub-channel # 2.
  • the access point AP transmits data to the fourth station STA4 through the third sub-channel # 3.
  • the access point AP transmits data to the fifth station STA5 through the fourth sub-channel # 4.
  • the first station STA1, the second station STA2, the third station STA3, the fourth station STA4, and the fifth station STA5 have four bandwidths of 5 MHz.
  • An ACK frame is transmitted to the AP through each sub-channel.
  • the first station STA1 and the second station SAT2 sequentially transmit ACK frames to the access point AP through the first sub-channel # 1.
  • the third station STA3 transmits an ACK frame to the access point AP through the second sub-channel # 2.
  • the fourth station STA4 transmits an ACK frame to the access point AP through the third sub-channel # 3.
  • the fifth station STA5 transmits an ACK frame to the access point AP through the fourth sub-channel # 4.
  • the predetermined time may be a short inter-frame space (SIFS) defined in 802.11.
  • the access point (AP) transmits an ACK frame on a channel having a 20MHz bandwidth.
  • the wireless communication terminal that does not support the embodiment of the present invention has completed data transmission between the access point AP and the first station STA1 to the fifth station STA5.
  • FIG. 24 illustrates an access point transmitting data to a plurality of stations through a multi-user A-MPDU according to another embodiment of the present invention, and each of the plurality of stations transmits an ACK frame through a channel having a bandwidth equal to or greater than the minimum unit frequency bandwidth. Show transmission.
  • each of the plurality of second wireless communication terminals that receive data from the first wireless communication terminal is the minimum unit.
  • the complete frame may be transmitted through a channel having a bandwidth greater than or equal to the frequency bandwidth.
  • the plurality of second wireless communication terminals may sequentially transmit a complete frame through a channel having a bandwidth equal to or greater than the minimum unit frequency bandwidth.
  • the plurality of second wireless communication terminals that receive data through the multi-user A-MPDU may sequentially transmit the complete frame together with the other second wireless communication terminals.
  • the transmission order of the plurality of second wireless communication terminals that have received data through the multi-user A-MPDU may be the same as the transmission order described with reference to FIG. 23.
  • the access point AP is a first station STA1, a second station STA2, a third station STA3, and a fourth station through each of four sub-channels having a bandwidth of 5 MHz. STA4 and data to a fifth station STA5.
  • the access point AP transmits a multi-user A-MPDU to the first station STA1 and the second station STA2 through a first sub-channel # 1.
  • the access point AP transmits data to the third station STA3 through the second sub-channel # 2.
  • the access point AP transmits data to the fourth station STA4 through the third sub-channel # 3.
  • the access point AP transmits data to the fifth station STA5 through the fourth sub-channel # 4.
  • the first station STA1 transmits an ACK frame to the access point AP through a channel having a bandwidth of 20 MHz. Specifically, after SIFS from when data is transmitted, the first station STA1 transmits an ACK frame to the access point AP through a channel having a bandwidth of 20 MHz.
  • the second station STA2 After the first station STA1 transmits the ACK frame, the second station STA2 transmits the ACK frame to the access point AP through a channel having a bandwidth of 20 MHz. Specifically, after SIFS from when the first station STA1 transmits the ACK frame, the second station STA2 transmits the ACK frame to the access point AP through a channel having a bandwidth of 20 MHz.
  • the third station STA3 transmits the ACK frame to the access point AP through a channel having a bandwidth of 20 MHz. Specifically, after SIFS from when the second station STA2 transmits the ACK frame, the third station STA3 transmits the ACK frame to the access point AP through a channel having a bandwidth of 20 MHz.
  • the fourth station STA4 transmits the ACK frame to the access point AP through a channel having a bandwidth of 20 MHz. Specifically, after SIFS from when the third station STA3 transmits the ACK frame, the fourth station STA4 transmits the ACK frame to the access point AP through a channel having a bandwidth of 20 MHz.
  • the fifth station STA5 transmits the ACK frame to the access point AP through a channel having a bandwidth of 20 MHz. Specifically, after SIFS from when the fourth station STA3 transmits the ACK frame, the fifth station STA5 transmits the ACK frame to the access point AP through a channel having a bandwidth of 20 MHz.
  • the plurality of second wireless communication terminals may grasp a predetermined order and transmit the completion frame to increase communication complexity.
  • considering even a plurality of second wireless communication terminals that receive data through the multi-user A-MPDU may increase communication complexity. An embodiment for solving this problem will be described with reference to FIG. 25.
  • FIG. 25 illustrates that an access point transmits data to a plurality of stations through a multi-user A-MPDU, and the access point transmits a BAR frame to each of the plurality of stations to induce ACK frame transmission.
  • the first wireless communication terminal transmits a completion request frame to the plurality of second wireless communication terminals, Based on the plurality of second wireless communication terminals may transmit a completion frame to the first wireless communication terminal.
  • the first wireless communication terminal may sequentially transmit a completion request frame to the plurality of second wireless communication terminals.
  • each of the plurality of second wireless communication terminals may transmit the completion frame after a predetermined time from when the completion request frame for each of the plurality of second wireless communication terminals is transmitted.
  • the predetermined time may be SIFS.
  • the second wireless communication terminal that transmits the completion frame first among the plurality of second wireless communication terminals transmits the completion frame to the first wireless communication terminal without receiving the completion request frame from the first wireless communication terminal. Can be.
  • the first wireless communication terminal may designate a second wireless communication terminal to transmit the first complete frame among the plurality of second wireless communication terminals.
  • the first wireless communication terminal may transmit a frame indicating a second wireless communication terminal to transmit the first complete frame among the plurality of second wireless communication terminals.
  • the second wireless communication terminal that transmits the completed frame first is the earliest alignment of identifiers representing the plurality of second wireless communication terminals in a preamble or header including information on the plurality of second wireless communication terminals. It may be a second wireless communication terminal.
  • the second wireless communication terminal that first transmits a complete frame may be a second wireless communication terminal having a largest MCS level of a signal used for data transmission for each second wireless communication terminal.
  • the second wireless communication terminal that first transmits the complete frame may be a second wireless communication terminal having the smallest MCS level of a signal used for data transmission for each second wireless communication terminal.
  • the second wireless communication terminal that transmits the completed frame first may be the second wireless communication terminal having the largest value indicating the traffic priority of the frame for each second wireless communication terminal.
  • the second wireless communication terminal that first transmits the complete frame may be the second wireless communication terminal having the largest value indicating the traffic priority of the frame for each second wireless communication terminal.
  • the value representing the traffic priority may be an access category in enhanced distributed channel access (EDCA).
  • the access point AP is a first station STA1, a second station STA2, a third station STA3, and a fourth station through each of four sub-channels having a bandwidth of 5 MHz. STA4 and data to a fifth station STA5.
  • the access point AP transmits a multi-user A-MPDU to the first station STA1 and the second station STA2 through a first sub-channel # 1.
  • the access point AP transmits data to the third station STA3 through the second sub-channel # 2.
  • the access point AP transmits data to the fourth station STA4 through the third sub-channel # 3.
  • the access point AP transmits data to the fifth station STA5 through the fourth sub-channel # 4.
  • the first station STA1 transmits an ACK frame to the access point AP through a channel having a bandwidth of 20 MHz. Specifically, after SIFS from when data is transmitted, the first station STA1 transmits an ACK frame to the access point AP through a channel having a bandwidth of 20 MHz.
  • the access point AP transmits a BAR frame to the second station STA2 through a channel having a bandwidth of 20 MHz.
  • the second station STA2 transmits an ACK frame to the access point AP through a channel having a bandwidth of 20 MHz. Specifically, after SIFS from when the BAR frame is transmitted, the second station STA2 transmits an ACK frame to the access point AP through a channel having a bandwidth of 20 MHz.
  • the access point AP transmits a BAR frame to the third station STA3 through a channel having a bandwidth of 20 MHz.
  • the third station STA3 transmits an ACK frame to the access point AP through a channel having a bandwidth of 20 MHz. Specifically, after SIFS from when the BAR frame is transmitted, the third station STA3 transmits an ACK frame to the access point AP through a channel having a bandwidth of 20 MHz.
  • the access point AP transmits a BAR frame to the fourth station STA4 through a channel having a bandwidth of 20 MHz.
  • the fourth station STA4 transmits an ACK frame to the access point AP through a channel having a bandwidth of 20 MHz. Specifically, after SIFS from when the BAR frame is transmitted, the fourth station STA4 transmits an ACK frame to the access point AP through a channel having a bandwidth of 20 MHz.
  • the access point AP transmits a BAR frame to the fifth station STA5 through a channel having a bandwidth of 20 MHz.
  • the fifth station STA5 transmits an ACK frame to the access point AP through a channel having a bandwidth of 20 MHz. Specifically, after SIFS from when the BAR frame is transmitted, the fifth station STA5 transmits an ACK frame to the access point AP through a channel having a bandwidth of 20 MHz.
  • FIG. 26 is a ladder diagram illustrating operations of a first wireless communication terminal and a second wireless communication terminal according to an embodiment of the present disclosure.
  • the first wireless communication terminal 400 generates a physical frame including data, a SIG-A field, and a SIG-B field (S2601).
  • the data is data for each of the plurality of second wireless communication terminals 500.
  • data may be transmitted through a channel allocated to each of the plurality of second wireless communication terminals 500.
  • the channel allocated to each of the plurality of second wireless communication terminals 500 may be a sub-channel having a bandwidth smaller than the minimum unit frequency bandwidth.
  • the first wireless communication terminal 400 may generate a SIG-B field based on the data.
  • the amount of information applied to each of the plurality of second wireless communication terminals 500 may vary depending on the number of the plurality of second wireless communication terminals 500. Therefore, the length of the SIG-B field may be variable.
  • the SIG-B field may have a variable length whose length varies according to data included in the SIG-B field. In particular, the number of OFDM symbols corresponding to the SIG-B field may be variable.
  • the SIG-B field may include information about the plurality of second wireless communication terminals 500 as described above.
  • the information on the plurality of second wireless communication terminal 500 is resource allocation information which is information on a communication medium allocated to each of the second wireless communication terminal 500 for communication with the first wireless communication terminal 400. It may include.
  • the SIG-B field may include an identifier for identifying each of the plurality of second wireless communication terminals 500.
  • the identifier may be a connection identifier for identifying a connection between the first wireless communication terminal 400 and the second wireless communication terminal 500.
  • the connection identifier may be an association identifier (AID) or a partial AID defined in 802.11.
  • the resource allocation information may include information about an MCS of a signal including data transmitted to the second wireless communication terminal 500.
  • the information on the MCS may be in the form of an MCS field that distinguishes a field for each second wireless communication terminal.
  • the information on the MCS may be in the form of an MCS vector field in which information on MCS of a plurality of signals including data for each of the plurality of second wireless communication terminals 500 is included in one field.
  • the resource allocation information for the second wireless communication terminal 500 may include information indicating the number of space-time streams.
  • the resource allocation information for the second wireless communication terminal 500 may include information indicating whether convolutional coding is applied to data included in the physical frame.
  • the resource allocation information for the second wireless communication terminal 500 includes information indicating whether extra OFDM symbols are required by applying low-density parity-check code (LDCP) coding to data. can do.
  • LDCP low-density parity-check code
  • the SIG-B field may include a field including information on the individual second wireless communication terminal 500 as an independent field.
  • the SIG-B field may include such independent fields as the number of second wireless communication terminals.
  • the independent field may be a field including any one of an individual CRC field and a tail field applied to the corresponding field.
  • the second wireless communication terminal 500 may decode an independent field including information about the second wireless communication terminal 500 and stop decoding the SIG-B field.
  • the physical frame may include a first field that includes all information about a first station, and may include a second field that includes all information about a second station.
  • the first station may stop decoding the signaling information after acquiring the information corresponding to the first station through the first field. Accordingly, the first station does not decode a field including information on another second station, thereby increasing communication efficiency.
  • the first wireless communication terminal 400 may generate a SIG-A field based on the SIG-B field.
  • the SIG-A field may have a predetermined length and a predetermined modulation and coding scheme (MCS).
  • the SIG-A field may include control information commonly applied to the plurality of second wireless communication terminals 500 as described above.
  • the SIG-A field includes information about a bandwidth of a channel, a guard interval (GI), a CRC indicating whether an SIG-A field includes an error, and a tail value indicating the termination of a SIG-A field. It may include at least one.
  • the SIG-A field may include information indicating the MCS of the signal including the SIG-B field.
  • the SIG-A field may include information indicating the number of OFDM symbols including the SIG-B field.
  • the first wireless communication terminal 400 transmits a physical frame to the second wireless communication terminal 500 (S2603).
  • the first wireless communication terminal 400 may transmit a corresponding SIG-B field to each of the plurality of second wireless communication terminals through a channel allocated to each of the plurality of second wireless communication terminals 500.
  • the first wireless communication terminal 400 may transmit the SIG-B field to the plurality of second wireless communication terminals 500 through a frequency band having a bandwidth equal to or greater than the minimum unit frequency bandwidth. In this case, as described above, the first wireless communication terminal 400 may transmit the SIG-B field to the plurality of second wireless communication terminals 500 in units of the minimum unit frequency bandwidth. In more detail, the first wireless communication terminal 400 may divide and transmit the SIG-B field in units of minimum unit frequency bandwidth.
  • the second wireless communication terminal 500 obtains data based on the physical frame (S2605).
  • the second wireless communication terminal 500 obtains the SIG-B field based on the SIG-A field.
  • the second wireless communication terminal 500 includes at least one of information indicating the MCS of the signal including the SIG-B field and information indicating the number of OFDM symbols including the SIG-B field based on the SIG-A field. Either one can be obtained.
  • the second wireless communication terminal 500 based on at least one of the information indicating the MCS of the signal including the acquired SIG-B field and the information indicating the number of OFDM symbols including the SIG-B field.
  • the B field may be received.
  • the second wireless communication terminal 500 may obtain data for the second wireless communication terminal 500 included in the physical frame based on the SIG-B field. As described above, the second wireless communication terminal 500 may obtain information about the second wireless communication terminal and receive data based on the obtained information about the second wireless communication terminal. In this case, the information on the second wireless communication terminal has been described above.
  • the second wireless communication terminal 500 may transmit a completion frame indicating completion of data reception to the first wireless communication terminal 400.
  • the channel allocated by the second wireless communication terminal 500 is a sub-channel having a bandwidth less than the minimum unit frequency bandwidth
  • the second wireless communication terminal 500 may transmit a completion frame through the corresponding sub-channel.
  • the first wireless communication terminal 400 may receive a complete frame from the plurality of second wireless communication terminals 500 and then transmit the complete frame through a channel having a bandwidth greater than or equal to the minimum unit frequency bandwidth.
  • the reception address of the completion frame may represent the first wireless communication terminal 400.
  • a channel having a bandwidth greater than or equal to the minimum unit frequency bandwidth may be obtained by dividing the entire channel used by the first wireless communication terminal 400 by the minimum unit frequency bandwidth.
  • the channel allocated by the second wireless communication terminal 500 is a sub-channel having a bandwidth less than the minimum unit frequency bandwidth
  • a plurality of agents that receive data from the first wireless communication terminal 400 are provided.
  • Each of the two wireless communication terminals 500 may transmit a complete frame through a channel having a bandwidth of at least a minimum unit frequency bandwidth.
  • the plurality of second wireless communication terminals 500 may sequentially transmit the complete frames to the first wireless communication terminal 400 as described above.
  • the second wireless communication terminal 500 when the first wireless communication terminal 400 does not receive a complete frame transmitted by any one of the second wireless communication terminals 500, the second wireless communication terminal 500.
  • the complete request frame may be transmitted for 500.
  • the first wireless communication terminal 400 may transmit a completion request frame to the corresponding two wireless communication terminals 500.
  • the first wireless communication terminal 400 may receive a completion frame of the other second wireless communication terminal 400 and then transmit a completion request frame to the second wireless communication terminal 500.
  • the plurality of second wireless communication terminals 500 which have received data through the multi-user A-MPDU, transmit the first wireless communication terminal 400 through a sub-channel allocated to the plurality of second wireless communication terminals 500.
  • the complete frames may be sequentially transmitted to the.
  • the plurality of second wireless communication terminals 500 that receive data through the multi-user A-MPDU may include a plurality of second preambles in a preamble or header including information about the plurality of second wireless communication terminals 500.
  • the complete frame may be sequentially transmitted to the first wireless communication terminal 400 based on the sorting order of the identifier indicating the wireless communication terminal 500.
  • the plurality of second wireless communication terminals 500 that have received data through the multi-user A-MPDU receive the completed frame based on the data sorting order included in the multi-user A-MPDU. 400 may be sequentially transmitted.
  • the plurality of second wireless communication terminals 500 that have received data through the multi-user A-MPDU are used for data transmission to each second wireless communication terminal 500 in the multi-user A-MPDU.
  • Complete frames may be sequentially transmitted to the first wireless communication terminal 400 based on the magnitude of the MCS level of the signal.
  • the plurality of second wireless communication terminals 500 that receive data through the multi-user A-MPDUs prioritize the traffic of the frames for each second wireless communication terminal 500 in the multi-user A-MPDUs.
  • Complete frames may be sequentially transmitted to the first wireless communication terminal 400 based on the value indicating the rank.
  • the plurality of second wireless communication terminals 500 that receive data through the multi-user A-MPDU transmits the completed frame to the first wireless communication based on a separate frame or field indicating a transmission order of the completed frames. It may be sequentially transmitted to the terminal 400.
  • the present invention has been described using the WLAN communication as an example, the present invention is not limited thereto and may be equally applicable to other communication systems such as cellular communication.
  • the methods, apparatus, and systems of the present invention have been described in connection with specific embodiments, some or all of the components, operations of the present invention may be implemented using computer systems having a general purpose hardware architecture.

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

Abstract

L'invention concerne un terminal de communication sans fil. Le terminal de communication sans fil comprend : une unité d'émission et de réception destinée à émettre et recevoir un signal sans fil; et un processeur destiné à commander un fonctionnement du terminal de communication sans fil. L'unité d'émission et de réception reçoit une trame physique contenant des données qui est transmise par un terminal de communication sans fil de base à chaque terminal d'une pluralité de terminaux de communication sans fil, parmi lesquels le terminal de communication sans fil. La trame physique comprend : un premier champ conçu pour signaler des informations devant être appliquées en commun à la pluralité de terminaux de communication sans fil; et un second champ contenant des informations sur chaque terminal de la pluralité de terminaux de communication sans fil. Le terminal de communication sans fil de base est un quelconque terminal de communication sans fil différent de la pluralité de terminaux de communication sans fil.
PCT/KR2015/010639 2014-10-08 2015-10-08 Procédé et terminal de communication sans fil WO2016056854A2 (fr)

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
KR20140135818 2014-10-08
KR10-2014-0135818 2014-10-08
KR10-2014-0135825 2014-10-08
KR20140135825 2014-10-08
KR20150034070 2015-03-11
KR10-2015-0034070 2015-03-11

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WO2016056854A2 true WO2016056854A2 (fr) 2016-04-14
WO2016056854A3 WO2016056854A3 (fr) 2016-05-26

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Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9088873B2 (en) * 2009-10-20 2015-07-21 Electronics And Telecommunications Research Institute Method for allocating group address in wireless local network area, method for transmitting response request frame and response frame in plurality of stations, and method for transmitting data using group address
US8861495B2 (en) * 2009-11-24 2014-10-14 Electronics And Telecommunications Research Institute Method for protecting data in a MU-MIMO based wireless communication system
AU2010327466B2 (en) * 2009-12-03 2014-08-21 Lg Electronics Inc. Method and apparatus for transmitting a frame in a wireless RAN system
EP2579477B1 (fr) * 2010-05-26 2017-04-19 LG Electronics Inc. Procédé et appareil d'émission-réception de données dans système de réseau local (lan) sans fil
WO2012074318A2 (fr) * 2010-12-02 2012-06-07 엘지전자 주식회사 Procédé et dispositif de transmission de signal de commande de liaison descendante dans système de communication sans fil

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