WO2016175561A1 - Wireless communication method and wireless communication terminal for transmitting frame indicating whether data is received - Google Patents

Abstract

A wireless communication terminal wirelessly communicating with a base wireless communication terminal is disclosed. An RF transmission and reception unit transmits and receives a wireless signal. A modulation and demodulation unit modulates and demodulates the wireless signal. The RF transmission and reception unit transmits, to the base wireless communication terminal, a wireless signal including data, and the modulation and demodulation unit demodulates a first frame from the wireless signal received from the base wireless communication terminal. The first frame indicates whether data transmitted by each of a plurality of wireless communication terminals including the wireless communication terminal is received.

Description

Wireless communication method and wireless communication terminal for transmitting a frame indicating whether data is received

The present invention relates to a wireless communication method and a wireless communication terminal for establishing a broadband link. Specifically, the present invention relates to a wireless communication method and a wireless communication terminal for increasing the data communication bandwidth of the terminal to increase the data communication efficiency.

Recently, with the spread of mobile devices, wireless LAN technology, which can provide fast wireless Internet service to them, is getting much attention. 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.

Since IEEE (Institute of Electrical and Electronics Engineers) 802.11 supports the initial wireless LAN technology using the 2.4GHz frequency, various standards of technology are being put into practice or being developed. First, IEEE 802.11b supports communication speeds up to 11Mbps while using frequencies in the 2.4GHz band. IEEE 802.11a, which has been commercialized after IEEE 802.11b, reduces the influence 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. Orthogonal Frequency Division Multiplexing, It uses OFDM technology to increase the communication speed up to 54Mbps. However, IEEE 802.11a has a shorter communication distance than IEEE 802.11b. And 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.

In addition, 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.

As the spread of wireless LANs is activated and applications are diversified, there is a need for a new wireless LAN system to support higher throughput (VHT) than the data throughput supported by IEEE 802.11n. It became. Among them, 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. This is accomplished by extending the 802.11n concept of wireless interfaces, including wider radio frequency bandwidth (up to 160 MHz), more MIMO spatial streams (up to eight), multi-user MIMO, and higher density modulation (up to 256 QAM). In addition, 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. However, the 60 GHz frequency band is difficult to pass through obstacles, and thus can be used only between devices in a short space.

On the other hand, as the 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.

In particular, as the number of devices using a wireless LAN increases, it is necessary to efficiently use a predetermined channel. Therefore, there is a need for a technology capable of efficiently using bandwidth by simultaneously transmitting data between a plurality of stations and an AP.

One embodiment of the present invention is to provide an efficient wireless communication method and a wireless communication terminal.

In particular, an embodiment of the present invention is to provide a wireless communication method and a wireless communication terminal for transmitting a frame indicating whether or not to receive data.

According to an embodiment of the present invention, a wireless communication terminal wirelessly communicating with a base wireless communication terminal may include: an RF transceiver for transmitting and receiving a radio signal; And a demodulation unit configured to demodulate and demodulate the radio signal, wherein the RF transceiver transmits a radio signal including data to the base radio communication terminal, and the modulator demodulates the first frame from a radio signal received from the base radio communication terminal. The demodulation signal indicates whether the first frame receives data transmitted from each of a plurality of wireless communication terminals including the wireless communication terminal.

The modulation and demodulation unit modulates data to be transmitted to the base wireless communication terminal based on a maximum value of the number of data identifiers designated by the base wireless communication terminal, and the data identifier may be an identifier for identifying data transmitted by the plurality of wireless communication terminals. have.

The maximum value of the number of data identifiers designated by the base wireless communication terminal may indicate the maximum value of the number of traffic identifiers (TIDs).

The maximum value of the number of data identifiers designated by the base wireless communication terminal may indicate the maximum value of the number of the plurality of wireless communication terminals.

The demodulation demodulator demodulates a second frame from a radio signal transmitted from the base radio communication terminal, obtains a maximum value of the number of data identifiers from the second frame, and the second frame includes: It can indicate information about allocated resources.

When the number of data identifiers increases, the size of the first frame may increase.

The modulation and demodulation unit modulates an Aggregate-MAC Protocol Data Unit (A-MPDU) transmitted to a base wireless communication terminal, wherein the A-MPDU transmits a plurality of MPDUs to one PSDU (PLCP Service Data Unit) in a physical layer, The plurality of MPDUs may include a first MPDU for transmitting data and a second MPDU for not transmitting data.

The A-MPDU may include an MPDU delimiter for dividing a boundary between the plurality of MPDUs, and the MPDU delimiter may include a field for identifying the first MPDU and the second MPDU.

The second MPDU may include feedback information indicating information on data transmission from the wireless communication terminal to the base wireless communication terminal.

The feedback information may include information regarding a buffer state of the wireless communication terminal, and the buffer state of the wireless communication terminal may indicate at least one of a size and a number of data waiting to be transmitted by the wireless communication terminal.

The modulation / demodulation unit may modulate valid time information indicating a period in which the feedback information is available.

The feedback information may be classified into a plurality of types, and the valid time information may be determined based on the plurality of types.

According to an embodiment of the present invention, a base wireless communication terminal wirelessly communicating with a plurality of wireless communication terminals includes an RF transceiver for transmitting and receiving a radio signal; And a demodulation unit for demodulating and demodulating the radio signal, wherein the RF transceiver unit receives a radio signal received from each of the plurality of radio communication terminals and includes data, and wherein the modulator demodulates the plurality of radios to the plurality of radio communication terminals. Each communication terminal may modulate a first frame indicating whether to receive data transmitted.

The modulation and demodulation unit modulates a maximum value of the number of data identifiers by the plurality of wireless communication terminals to be transmitted to each of the plurality of wireless communication terminals, and wherein each of the plurality of wireless communication terminals is based on the maximum value of the number of data identifiers. Data is transmitted to a communication terminal, and the data identifier may be an identifier for identifying data transmitted by the plurality of wireless communication terminals.

The maximum value of the number of data identifiers may indicate the maximum value of the number of traffic identifiers (TIDs).

The maximum value of the number of data identifiers may represent the maximum value of the number of the plurality of wireless communication terminals.

The modulation and demodulation unit may modulate a second frame that transmits the maximum value of the number of data identifiers, and the second frame may indicate information about resources allocated to each of the plurality of wireless communication terminals.

When the number of data identifiers increases, the size of the first frame may increase.

The demodulation unit demodulates an Aggregate-MAC Protocol Data Unit (A-MPDU) from a radio signal received from any one of the plurality of wireless communication terminals, and the A-MPDU is a plurality of MAC Protocol Data Units (MPDUs) in a physical layer. Is transmitted to a single PLCU Service Data Unit (PSDU), and the plurality of MPDUs includes a first MPDU for transmitting data and a second MPDU for not transmitting data, and the second MPDU includes the plurality of wireless communication terminals. It may include feedback information indicating information on the data transmission for each of the base wireless communication terminal.

Method of operation of a wireless communication terminal according to an embodiment of the present invention comprises the steps of transmitting data to the base wireless communication terminal; And receiving a first frame indicating whether data received by each of a plurality of wireless communication terminals including the wireless communication terminal is received from the base wireless communication terminal.

One embodiment of the present invention provides an efficient wireless communication method and a wireless communication terminal.

In particular, an embodiment of the present invention provides a wireless communication method and a wireless communication terminal for transmitting a frame indicating whether data is received.

1 illustrates a WLAN system according to an embodiment of the present invention.

2 shows a WLAN system according to another embodiment of the present invention.

3 is a block diagram showing a configuration of a station according to an embodiment of the present invention.

4 is a block diagram illustrating a configuration of an access point according to an embodiment of the present invention.

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 shows that a first wireless communication terminal transmits a frame indicating whether data received by each of a plurality of second stations is received.

7 illustrates a method of limiting a size of a frame indicating whether a first wireless communication terminal receives data transmitted by a plurality of second wireless communication terminals according to another embodiment of the present invention.

8 illustrates a method of limiting a size of a frame indicating whether a first wireless communication terminal receives data transmitted by a plurality of second wireless communication terminals through a frequency bandwidth greater than 20 MHz according to another embodiment of the present invention. Shows.

9 is a diagram illustrating the size of a frame indicating whether a first wireless communication terminal receives each of a plurality of MPDUs transmitted by each of a plurality of second wireless communication terminals, according to another embodiment of the present invention; When limiting based on the number, the number of second wireless communication terminals that can communicate with the first wireless communication terminal according to the transmission rate is shown.

FIG. 10 is a diagram illustrating a size of a frame indicating whether a first wireless communication terminal receives all MPDUs transmitted by each of a plurality of second wireless communication terminals, based on the number of second wireless communication terminals. Referring to FIG. If limited to, the number of second wireless communication terminals that can communicate with the first wireless communication terminal according to the transmission rate is shown.

FIG. 11 illustrates a method of limiting a size of a frame indicating whether data received by a plurality of second wireless communication terminals is received through a trigger frame by a first wireless communication terminal according to another embodiment of the present invention.

12 is a view illustrating a method of preventing a transmission collision between an M-BA transmission of a first wireless communication terminal and a hidden wireless communication terminal through an L-SIG by a second wireless communication terminal according to another embodiment of the present invention.

FIG. 13 is a view illustrating the M-BA transmission and the hidden node of the first wireless communication terminal through the L-SIG when the first wireless communication terminal uses a bandwidth of 20 MHz or more according to another embodiment of the present invention. Demonstrates how to avoid collisions between transmissions.

FIG. 14 is a view illustrating a M-BA transmission and a hidden node of a first wireless communication terminal through an L-SIG when the first wireless communication terminal transmits a trigger frame according to another embodiment of the present invention. Demonstrates how to avoid collisions between transmissions.

FIG. 15 is a view illustrating a method of preventing a collision between M-BA transmission of a first wireless communication terminal and transmission of a hidden node through an L-SIG by a second wireless communication terminal according to another embodiment of the present invention.

FIG. 16 is a view illustrating an M-BA transmission and a hidden node of a first wireless communication terminal through an L-SIG when the first wireless communication terminal uses a bandwidth of 20 MHz or more according to another embodiment of the present invention. Demonstrates how to avoid collisions between transmissions.

FIG. 17 illustrates a case in which a second wireless communication terminal transmits a M-BA and a hidden node of a first wireless communication terminal through an L-SIG when the first wireless communication terminal transmits a trigger frame according to another embodiment of the present invention. Demonstrates how to avoid collisions between transmissions.

18 is a view illustrating a method of preventing transmission collision of a hidden node by adjusting transmission power by a first wireless communication terminal according to another embodiment of the present invention.

19 shows a form of an A-MPDU according to an embodiment of the present invention.

20 shows a form of an A-MPDU according to another embodiment of the present invention.

21 shows a MAC header according to an embodiment of the present invention.

22 shows a MAC header of an MPDU included in an A-MPDU according to another embodiment of the present invention.

23 illustrates an MPDU delimiter structure included in an A-MPDU according to an embodiment of the present invention.

24 is a view illustrating an MPDU delimiter structure included in an A-MPDU according to another embodiment of the present invention.

25 is a view illustrating a wireless communication terminal transmitting various information through an A-MPDU according to an embodiment of the present invention.

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 invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.

In addition, when a part is said to "include" a certain component, which means that it may further include other components, except to exclude other components unless otherwise stated.

This application claims priority based on Korean Patent Application Nos. 10-2015-0059265, 10-2015-0062587, and 10-2015-0067955, and is described in each of the above applications as a basis for the priority. The embodiments and descriptions set forth herein are to be included in the detailed description of the present application.

1 illustrates a WLAN system according to an embodiment of the present invention. 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. In general, the BSS may be classified into an infrastructure BSS (Independent BSS) and an Independent BSS (IBSS), and FIG. 1 illustrates an infrastructure BSS.

As shown in FIG. 1, an infrastructure BSS (BSS1, BSS2) is an access point (PCP / AP) that is a station that provides one or more stations (STA1, STA2, STA3, STA_d, STA5), and a distribution service. -1, PCP / AP-2), and a Distribution System (DS) connecting multiple access points (PCP / AP-1, PCP / AP-2).

A station (STA) 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. In addition, in the present specification, the term '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 (AP) is an entity that provides access to a distribution system (DS) via a wireless medium for an associated station to the AP. In the infrastructure BSS, communication between non-AP stations is performed via an AP. However, when a direct link is established, direct communication between non-AP stations is possible. Meanwhile, in the present invention, 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.

The plurality of infrastructure BSSs may be interconnected through a distribution system (DS). At this time, the plurality of BSSs connected through the distribution system is referred to as an extended service set (ESS).

2 illustrates an independent BSS, which is a wireless LAN system according to another embodiment of the present invention. In the embodiment of FIG. 2, the same or corresponding parts as those of the embodiment of FIG. 1 will be omitted.

Since 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.

3 is a block diagram showing the configuration of a station 100 according to an embodiment of the present invention.

As shown, the station 100 according to an embodiment of the present invention may include a processor 110, a transceiver 120, a user interface 140, a display unit 150, and a memory 160. .

First, 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. In more detail, the transceiver 120 includes an RF transceiver 121 and a modulator 123. The RF transceiver 121 transmits and receives a radio signal. The demodulation demodulator 123 modulates and demodulates a radio signal. According to an embodiment, the transceiver 120 may include at least one transceiver module using different frequency bands. For example, the transceiver 120 may include a transceiver module of different frequency bands such as 2.4 GHz, 5 GHz, and 60 GHz. According to an embodiment, 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. When the station 100 includes a plurality of transmit / receive modules, each transmit / receive module may be provided in an independent form, or a plurality of modules may be integrated into one chip.

Next, 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.

Next, 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. In addition, the memory 160 stores a control program used in the station 100 and various data according thereto. Such 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. In addition, the processor 110 may control each unit of the station 100 described above, and may control data transmission and reception between the units. According to an embodiment of the present disclosure, 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. In addition, 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.

4 is a block diagram illustrating a configuration of an AP 200 according to an exemplary embodiment.

As shown, the AP 200 according to an embodiment of the present invention may include a processor 210, a transceiver 220, and a memory 260. In FIG. 4, overlapping descriptions of parts identical or corresponding to those of the station 100 of FIG. 3 will be omitted.

Referring to FIG. 4, the AP 200 according to the present invention includes a transceiver 220 for operating a BSS in at least one frequency band. In more detail, the transceiver 220 includes an RF transceiver 221 and a modulator 223. The RF transceiver 221 transmits and receives a radio signal. The modulation / demodulation unit 223 modulates and demodulates a radio signal. As described above in the embodiment of FIG. 3, 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. Preferably, 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.

Next, the memory 260 stores a control program used in the AP 200 and various data according thereto. Such a control program may include an access program for managing a connection of a station. In addition, the processor 210 may control each unit of the AP 200 and may control data transmission and reception between the units. According to an embodiment of the present disclosure, 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. In this case, the communication setting message may include information on the access priority condition of each station. In addition, 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.

5 schematically illustrates a process in which an STA establishes a link with an AP.

Referring to FIG. 5, the link between the STA 100 and the AP 200 is largely established through three steps of scanning, authentication, and association. First, the scanning step is a step in which the STA 100 obtains access information of a BSS operated by the AP 200. As a method for performing scanning, 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. There is an active scanning method of transmitting a probe request (S103) and receiving a probe response from the AP (S105) to obtain access information.

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. After the authentication step is performed, the STA 100 transmits an association request (S109a), receives an association response from the AP 200 (S109b), and performs the association step. In the present specification, the association (association) basically means a wireless coupling, the present invention is not limited to this, the binding in the broad sense may include both wireless coupling and wired coupling.

Meanwhile, the 802.1X based authentication step S111 and the IP address obtaining step S113 through DHCP may be performed. In FIG. 5, 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.

When data is transmitted using orthogonal frequency division multiple access (OFDMA) or multi input multi output (MIMO), any one wireless communication terminal may simultaneously transmit data to a plurality of wireless communication terminals. In addition, any one wireless communication terminal can receive data from a plurality of wireless communication terminals at the same time.

For convenience of description, 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. This is called a communication terminal. The first wireless communication terminal may also be referred to as a base wireless communication terminal (device). In addition, 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. In more detail, the first wireless communication terminal may function as a cell coordinator. In this case, the first wireless communication terminal may be the access point 200. In addition, the second wireless communication terminal may be a station 100 associated with the access point 200. According to a specific embodiment of the present invention, 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. In addition, the first wireless communication terminal may be at least one of a base station, an eNB, and a transmission point (TP).

In addition, the wireless communication terminal may transmit an aggregate MPDU (A-MPDU) including a plurality of MAC Protocol Data Units (MPDUs). In this case, the A-MPDUs are a plurality of MPDUs transmitted to one PSDU (PLCP Service Data Unit) in the physical layer. Through this, the data transmission efficiency of the wireless communication terminal can be improved.

6 to 26, a description will be given of an operation in which a plurality of second wireless communication terminals transmit data, and the first wireless communication terminal receives data. In particular, an operation in which a plurality of second wireless communication terminals transmit A-MPDUs and the first wireless communication terminal receives A-MPDUs will be described.

FIG. 6 shows that a first wireless communication terminal transmits a frame indicating whether data received by each of a plurality of second stations is received.

The first wireless communication terminal may transmit a frame indicating whether a MAC Protocol Data Unit (MPDU) transmitted by the second wireless communication terminal is received. In this case, a frame indicating whether data received by the plurality of second wireless communication terminals is received may be referred to as a multi-STA block ACK (M-BA). Through the M-BA, the first wireless communication terminal can reduce a time required for transmitting a frame indicating whether data is received to a plurality of second wireless communication terminals. However, when the first wireless communication terminal transmits the M-BA, receiving an ACK frame indicating whether to receive one MPDU transmitted by one wireless communication terminal or a plurality of MPDUs transmitted by any one wireless communication terminal More transmission time is required than when transmitting a Block ACK (BA) frame indicating whether or not. Accordingly, it may be disadvantageous in a competition procedure for transmitting data with a wireless communication terminal that does not receive data transmission of the first wireless communication terminal. For convenience of description, a wireless communication terminal that does not receive data transmission of the first wireless communication terminal is referred to as a hidden wireless communication terminal. In addition, the transmission of the hidden wireless communication terminal and the transmission of the M-BA in the first wireless communication terminal may collide.

When the hidden wireless communication terminal fails to decode the MAC frame or the physical frame, the hidden wireless communication terminal waits a predetermined time. For convenience of explanation, the waiting time is referred to as a hidden waiting time. After the hidden waiting time elapses, the hidden wireless communication terminal performs a contention procedure based on back-off. In this case, the hidden wait time may be an extended inter-frame space (EIFS) defined in the 802.11 standard. When the size of the M-BA increases, after the first wireless communication terminal receives the data, it may take more than the EIFS time until the plurality of second wireless communication terminals receive the M-BA. In this case, the hidden wireless communication terminal has priority in the competition procedure for transmitting data than the first wireless communication terminal and the plurality of second wireless communication terminals. Specifically, the following situation may occur.

If the M-BA follows the Multi-TID BA format defined in the 802.11 standard, and the number of TIDs (Traffic Identifier) corresponding to the MPDU transmitted by each second wireless communication terminal through the A-MPDU is 1, The length of BA follows the formula:

Length of M-BA = 22 + N_STA x 12 Bytes

In this case, the TID is an identifier for identifying an MSDU (MAC Service Data Unit) included in the MPDU.

In addition, 20us is required for M-BA preamble transmission. Assuming that the number of the second wireless communication terminals is eight and the first wireless communication terminal follows the MCS0 defined in the 802.11 standard, the time required for transmitting the M-BA is as follows.

20us + (22 + 12 x 8) / 6Mbps ≒ 177.3us

In addition, after the first wireless communication terminal receives the data, after the SIFS time elapses, the first wireless communication terminal transmits the M-BA to the plurality of second wireless communication terminals. At this time, SIFS is 16us. Therefore, after the first wireless communication terminal receives the data, it takes 193.3 us for the plurality of second wireless communication terminals to transmit the M-BA to the transmitter.

In the 802.11 standard, the duration of EIFS is defined as follows.

EIFS = SIFS + Maximum_ACK_Duration + DIFS

Accordingly, the duration of the EIFS is 94us. Therefore, the hidden wireless communication terminal that does not receive the data transmission of the first wireless communication terminal initiates a competition procedure based on the back off procedure before the M-BA reception is terminated. If the back off counter acquired by the hidden wireless communication terminal is sufficiently small, the transmission of the hidden wireless communication terminal and the transmission of the M-BA of the first wireless communication terminal may collide.

In order to solve this problem, the size of the M-BA transmitted by the first wireless communication terminal can be limited. This will be described in detail with reference to FIGS. 7 to 11.

7 illustrates a method of limiting a size of a frame indicating whether a first wireless communication terminal receives data transmitted by a plurality of second wireless communication terminals according to another embodiment of the present invention. FIG. 8 is a view illustrating a method for limiting the size of indicating whether a first wireless communication terminal receives data transmitted by a plurality of second wireless communication terminals through a frequency bandwidth greater than 20 MHz according to another embodiment of the present invention. .

The first wireless communication terminal may transmit information for limiting the size of a frame indicating whether or not the data transmitted by each of the second wireless communication terminals is received to the second wireless communication terminal. In this case, the second wireless communication terminal may transmit data to the plurality of second wireless communication terminals based on information for limiting the size of a frame indicating whether the data transmitted by each of the plurality of second wireless communication terminals is received. In more detail, the first wireless communication terminal may limit the number of identifiers for identifying data transmitted by the plurality of second wireless communication terminals. For convenience of description, an identifier for identifying data transmitted by the plurality of second wireless communication terminals is referred to as a data identifier. In this case, the data may be data included in the A-MPDU. Each of the plurality of second wireless communication terminals transmits data. In addition, the data may include a plurality of MSDUs. Therefore, the data transmitted by the plurality of second wireless communication terminals can be identified by the second wireless communication terminal and the MSDU. Accordingly, the data identifier may indicate at least one of the TID and the identifier of the second wireless communication terminal. In more detail, the first wireless communication terminal may limit the maximum number of TIDs that data transmitted by one second wireless communication terminal may have. According to another specific embodiment, the first wireless communication terminal may limit the number of second wireless communication terminals that transmit data to the first wireless communication terminal. This is because when the number of TIDs included in the data increases, the size of the M-BA increases to indicate whether or not the MPDU corresponding to each TID is received. In addition, when the number of second wireless communication terminals that transmit data increases, the size of the M-BA increases to indicate whether the MPDU corresponding to the second wireless communication terminal is received.

Accordingly, the second wireless communication terminal can transmit data based on the maximum value of the number of data identifiers designated by the first wireless communication terminal. In more detail, the second wireless communication terminal may transmit data based on the maximum number of TIDs designated by the first wireless communication terminal. For example, the second wireless communication terminal may transmit a plurality of MPDUs having a number of TIDs less than or equal to the maximum number of TIDs designated by the first wireless communication terminal. In more detail, the second wireless communication terminal may transmit data based on the maximum number of second wireless communication terminals designated by the first wireless communication terminal.

In this case, the first wireless communication terminal may transmit a plurality of MPDUs through the A-MPDU.

In addition, the first wireless communication terminal may limit the number of data identifiers transmitted by the second wireless communication terminal based on the hidden waiting time. In detail, when the hidden wireless communication terminal fails to decode the MAC frame or the physical frame, the first wireless communication terminal may determine that the M-BA transmission of the first wireless communication terminal is terminated before the hidden waiting time elapses. The maximum value of the number can be determined. In this case, the hidden waiting time may be EIFS as described above.

In this case, as in the embodiments of FIGS. 7 and 8, the hidden wireless communication terminal starts a contention procedure based on the back-off after the transmission of the M-BA is finished. Accordingly, transmission collision between the hidden wireless communication terminal and the wireless communication terminal supporting the embodiment of the present invention can be prevented.

As described above, the first wireless communication terminal may determine the maximum value of the number of data identifiers for transmitting data to the first wireless communication terminal based on the hidden waiting time. Also, the first wireless communication terminal may determine the maximum value of the number of data identifiers based on the MCSs that the plurality of second wireless communication terminals can receive. Such specific embodiments will be described with reference to FIGS. 9 to 10.

9 is a diagram illustrating the size of a frame indicating whether a first wireless communication terminal receives each of a plurality of MPDUs transmitted by each of a plurality of second wireless communication terminals, according to another embodiment of the present invention; When limiting based on the number, the number of second wireless communication terminals that can communicate with the first wireless communication terminal according to the transmission rate is shown. FIG. 10 is a diagram illustrating a size of a frame indicating whether a first wireless communication terminal receives all MPDUs transmitted by each of a plurality of second wireless communication terminals, based on the number of second wireless communication terminals. Referring to FIG. If limited to, the number of second wireless communication terminals that can communicate with the first wireless communication terminal according to the transmission rate is shown.

As described above, the hidden wait time may be EIFS, and the time difference may be SIFS until the first wireless communication terminal receives the A-MPDU and transmits the M-BA. In this case, in order for the hidden wireless communication terminal and the wireless communication terminal supporting the embodiment of the present invention to compete fairly, it is necessary for the first wireless communication terminal to transmit the M-BA and the second wireless communication terminal to receive the M-BA. The time to become should be 78us or less.

The M-BA may indicate whether the first wireless communication terminal receives the plurality of MPDUs transmitted by each of the plurality of second wireless communication terminals. When the number of traffic identifiers (TIDs) corresponding to the MPDUs transmitted through the A-MPDUs by each second wireless communication terminal is 1, the length of the M-BA may satisfy the following equation.

Length of M-BA = 22 + N_STA x 12 Bytes

In addition, the M-BA may indicate whether the first wireless communication terminal has received one MPDU transmitted by each of the plurality of second wireless communication terminals. When the number of TIDs (Traffic Identifier) corresponding to the MPDU transmitted by each second wireless communication terminal through the A-MPDU is 1, the length of the M-BA may satisfy the following equation.

Length of M-BA = 22 + N_STA x 2 Bytes

Thus, the length of M-BA varies according to the use of M-BA. FIG. 9 illustrates that the first wireless communication terminal designates the first wireless communication terminal according to the MCS defined in the 802.11 standard when the M-BA indicates whether the first wireless communication terminal receives each of a plurality of MPDUs transmitted by each of the plurality of second wireless communication terminals. The maximum number of first wireless communication terminals that can be shown is shown. FIG. 10 shows that the first wireless communication terminal can designate the first wireless communication terminal according to the MCS defined in the 802.11 standard when the M-BA indicates whether the first wireless communication terminal has received all MPDUs transmitted by each of the plurality of second wireless communication terminals. The maximum number of first wireless communication terminals is shown.

As such, the first wireless communication terminal may determine the maximum value of the number of data identifiers based on the MCSs that the plurality of second wireless communication terminals can receive. In this case, the first wireless communication terminal may signal the maximum value of the determined number of data identifiers to the plurality of second wireless communication terminals. This will be described in detail with reference to FIG. 11.

FIG. 11 illustrates a method of limiting a size of a frame indicating whether data received by a plurality of second wireless communication terminals is received through a trigger frame by a first wireless communication terminal according to another embodiment of the present invention.

The first wireless communication terminal may transmit a trigger frame indicating information about the plurality of second wireless communication terminals to transmit data to the first wireless communication terminal to the plurality of second wireless communication terminals. In this case, the information about the plurality of second wireless communication terminals to transmit data to the first wireless communication terminal may indicate a plurality of second wireless communication terminals to transmit data to the first wireless communication terminal. In addition, the information about the plurality of second wireless communication terminals to transmit data to the first wireless communication terminal may include information about resources allocated to each of the plurality of second wireless communication terminals. In this case, the information about resources allocated to each of the plurality of second wireless communication terminals may include information about frequency bands allocated to each of the plurality of second wireless communication terminals. In addition, the information about the resources allocated to each of the plurality of second wireless communication terminals may include information about the transmission time point allocated to each of the plurality of second wireless communication terminals.

In addition, according to an embodiment of the present invention, the trigger frame may include the maximum value of the number of data identifiers described above. Therefore, the first wireless communication terminal may transmit a trigger frame including the maximum value of the number of data identifiers. The second wireless communication terminal may receive the trigger frame and transmit data to the first wireless communication terminal based on the maximum value of the number of data identifiers included in the trigger frame. In more detail, the second wireless communication terminal may obtain the maximum value of the number of data identifiers from the trigger frame. In this case, the second wireless communication terminal may transmit the A-MPDU to the first wireless communication terminal based on the maximum value of the number of data identifiers obtained. According to a specific embodiment, the second wireless communication terminal may transmit an A-MPDU including an MPDU corresponding to a number of data identifiers equal to or less than the maximum value of the number of acquired data identifiers.

In the embodiment of FIG. 11, the first wireless communication terminal transmits a trigger frame including the maximum value of the number of data identifiers.

The plurality of second wireless communication terminals transmit data based on the maximum value of the number of data identifiers.

The first wireless communication terminal transmits an M-BA frame indicating whether to receive data transmitted from the plurality of second wireless communication terminals to the plurality of second wireless communication terminals.

In this case, the plurality of second wireless communication terminals receive the M-BA frame, and the hidden wireless communication terminal (Partialy Hidden STA) starts a competition procedure for data transmission.

Therefore, a collision between transmission of the first wireless communication terminal M-BA frame and transmission of the hidden wireless communication terminal does not occur.

The physical frame transmitted by the wireless communication terminal according to an embodiment of the present invention may include an L-SIG field signaling information that can be decoded by both the wireless communication terminal and the legacy wireless communication terminal according to the present invention. have. In this case, the wireless communication terminal may signal a TXOP (Transmit Opportunity) to be used by the wireless communication terminal that has transmitted the physical frame through the L-SIG field. In this case, TXOP represents a time interval in which the wireless communication terminal uses the transmission medium (medium). In more detail, the L-SIG field may signal TXOP to be used by a wireless communication terminal that has transmitted a physical frame through a field indicating the length of the physical frame and a field indicating the data rate of the physical frame. According to a specific embodiment, the legacy wireless communication terminal determines that the physical frame is transmitted for a time divided by the length of the physical frame by the data rate. Therefore, the legacy wireless communication terminal does not approach the frequency band in which the physical frame is transmitted. At this time, the wireless communication terminal according to an embodiment of the present invention can determine the time when the actual physical frame is transmitted through the HE-SIG field. By using the L-SIG field, the second wireless communication terminal can prevent a transmission collision between the M-BA transmission of the first wireless communication terminal and the hidden wireless communication terminal. This will be described with reference to FIGS. 12 to 17.

12 is a view illustrating a method of preventing a transmission collision between an M-BA transmission of a first wireless communication terminal and a hidden wireless communication terminal through an L-SIG by a second wireless communication terminal according to another embodiment of the present invention. FIG. 13 is a view illustrating the M-BA transmission and the hidden node of the first wireless communication terminal through the L-SIG when the first wireless communication terminal uses a bandwidth of 20 MHz or more according to another embodiment of the present invention. Demonstrates how to avoid collisions between transmissions.

While transmitting data to the first wireless communication terminal, the second wireless communication terminal may set the TXOP until the time when the second wireless communication terminal receives the M-BA from the first wireless communication terminal through the L-SIG. In more detail, the second wireless communication terminal may set a value of a field indicating the duration of the physical frame of the L-SIG to the time required for the second wireless communication terminal to receive the M-BA from the first wireless communication terminal. Since the plurality of second wireless communication terminals receive the M-BA from the first wireless communication terminal, the time of the TXOP set by the plurality of second wireless communication terminals through the L-SIG field may be the same.

In the embodiment of FIG. 12, a plurality of second wireless communication terminals transmit data to the first wireless communication terminal. In this case, each of the plurality of second wireless communication terminals sets the TXOP until the time required for the second wireless communication terminal to receive the M-BA from the first wireless communication terminal through the L-SIG of the physical frame. Also, the hidden STA starts a contention procedure for transmitting data after EIFS from the time when the second wireless communication terminal receives the M-BA.

In the embodiment of FIG. 13, the plurality of second wireless communication terminals transmit data to the first wireless communication terminal through a frequency band of 80 MHz. As in the embodiment of FIG. 12, the plurality of second wireless communication terminals set the TXOP through the L-SIG, and the Hidden STA operates accordingly. Since the plurality of second wireless communication terminals transmits data to the first wireless communication terminal through a frequency band of 80 MHz, the hidden STA may transmit data after EIFS from the time when the second wireless communication terminal receives the M-BA. The competition procedure for transmitting the UE starts in the first channel (Channel # 1), it is determined whether the idle state during the SIFS in the second channel (Channel # 2) to the fourth channel (Channel # 4).

It may be difficult for the second wireless communication terminal to accurately determine the time required for M-BA transmission of the first wireless communication terminal. Therefore, there is a need for a solution to this. This will be described with reference to FIG. 14.

FIG. 14 is a view illustrating a M-BA transmission and a hidden node of a first wireless communication terminal through an L-SIG when the first wireless communication terminal transmits a trigger frame according to another embodiment of the present invention. Demonstrates how to avoid collisions between transmissions.

The second wireless communication terminal may determine a TXOP value to be set through the L-SIG field based on the trigger frame described above. In more detail, the first wireless communication terminal may signal a TXOP value to be set by the second wireless communication terminal. The second wireless communication terminal may acquire a TXOP value from the trigger frame and set the L-SIG field according to the obtained TXOP value.

As described above, while the second wireless communication terminal transmits data to the first wireless communication terminal, it sets the TXOP until the time when the second wireless communication terminal receives the M-BA from the first wireless communication terminal through the L-SIG. Can be. At this time, the second wireless communication terminal completes the M-BA reception, and participates in a competition procedure for transmitting data when the transmission medium is idle during the DIFS (DCF Inter-Frame Space). However, the hidden wireless communication terminal waits for the EIFS from when the second wireless communication terminal completes the reception of the M-BA, and then participates in a competition procedure for transmitting data. Therefore, in the competition procedure, the second wireless communication terminal has priority over the hidden wireless communication terminal. An embodiment for solving this problem will be described with reference to FIGS. 15 to 17.

FIG. 15 is a view illustrating a method of preventing a collision between M-BA transmission of a first wireless communication terminal and transmission of a hidden node through an L-SIG by a second wireless communication terminal according to another embodiment of the present invention. FIG. 16 is a view illustrating an M-BA transmission and a hidden node of a first wireless communication terminal through an L-SIG when the first wireless communication terminal uses a bandwidth of 20 MHz or more according to another embodiment of the present invention. Demonstrates how to avoid collisions between transmissions.

The second wireless communication terminal has elapsed by a first predetermined time for determining whether the second wireless communication terminal is in an idle state from when the second wireless communication terminal receives the M-BA from the first wireless communication terminal through the L-SIG. TXOP may be set by subtracting the second predetermined time from which the legacy wireless communication terminal waits. In this case, the first predetermined time may be DIFS. In addition, the second predetermined time may be EIFS. In more detail, EIFS may be SIFS, ACK transmission time according to the slowest data rate, and DIFS. According to the 802.11 standard, the SIFS plus the ACK transmission time for the slowest data rate is 60us.

In the embodiment of FIG. 15, a plurality of second wireless communication terminals transmit data to the first wireless communication terminal. In this case, each of the plurality of second wireless communication terminals subtracts EIFS from the time that the DIFS has elapsed from when the second wireless communication terminal receives the M-BA from the first wireless communication terminal through the L-SIG of the physical frame. Set TXOP by time. Also, the hidden station starts a contention procedure for transmitting data from the second wireless communication terminal when the second wireless communication terminal receives the M-BA.

In the embodiment of FIG. 16, the plurality of second wireless communication terminals transmit data to the first wireless communication terminal through a frequency band of 80 MHz. As in the embodiment of FIG. 12, the plurality of second wireless communication terminals set the TXOP through the L-SIG, and the Hidden STA operates accordingly. Since the plurality of second wireless communication terminals transmits data to the first wireless communication terminal through a frequency band of 80 MHz, the hidden station transmits data when the second wireless communication terminal receives the M-BA. The competition procedure for the first channel (Channel # 1) is started, it is determined whether the idle (idle) state during the SIFS in the second channel (Channel # 2) to the fourth channel (Channel # 4).

FIG. 17 illustrates a case in which a second wireless communication terminal transmits a M-BA and a hidden node of a first wireless communication terminal through an L-SIG when the first wireless communication terminal transmits a trigger frame according to another embodiment of the present invention. Demonstrates how to avoid collisions between transmissions.

As described above, the second wireless communication terminal may determine the TXOP value to be set through the L-SIG field based on the trigger frame described above. In more detail, the first wireless communication terminal may signal a TXOP value to be set by the second wireless communication terminal. The second wireless communication terminal may acquire a TXOP value from the trigger frame and set the L-SIG field according to the obtained TXOP value. In this case, the end time of the TXOP value is triggered at a time elapsed by a first predetermined time for determining whether the second wireless communication terminal is idle from when the second wireless communication terminal receives the M-BA from the first wireless communication terminal. The time may be as much as subtracting the second predetermined time the wireless communication terminal waits.

As described with reference to FIGS. 12 to 17, when the protection of the hidden wireless communication terminal is set through the L-SIG, transmission collision between the first wireless communication terminal and the hidden wireless communication terminal is prevented without limiting the size of the M-BA. can do.

6 to 17 are all problems caused by a hidden wireless communication terminal. Therefore, if the possibility of hidden wireless communication terminal is reduced, this problem can be solved.

18 is a view illustrating a method of preventing transmission collision of a hidden node by adjusting transmission power by a first wireless communication terminal according to another embodiment of the present invention.

Hidden wireless communication terminal is a problem caused by the coverage of the signal transmitted by the first wireless communication terminal and the second wireless communication terminal is different. Therefore, if the coverage of the signal transmitted by the first wireless communication terminal is increased, this problem can be reduced.

The first wireless communication terminal may change the transmission power when transmitting the M-BA. In more detail, the first wireless communication terminal may use a larger transmission power than other cases when transmitting the M-BA. For example, the first wireless communication terminal may use a larger transmission power when transmitting the M-BA than when transmitting data. In another specific embodiment, the first wireless communication terminal may increase the transmission power for transmitting the M-BA according to the length of the M-BA. In detail, when the length of the M-BA is greater than or equal to the reference value, the first wireless communication terminal may increase transmission power for transmitting the M-BA.

In the embodiment of FIG. 18, the AP uses higher transmit power than other cases when transmitting the M-BA. Therefore, a hidden STA that does not receive other signals transmitted by the AP may also receive an M-BA transmitted by the AP.

19 through 25, the specific form of the A-MPDU will be described.

19 shows a form of an A-MPDU according to an embodiment of the present invention.

A-MPDU according to an embodiment of the present invention includes a plurality of MPDU, MPDU delimiter for distinguishing the boundaries between the plurality of MPDU and signaling information about the MPDU, A-MPDU sub-frame of a constant size A pad for draining. In this case, the constant size may be 4 octets.

In the embodiment of FIG. 19, the A-MPDU includes only a frame for transmitting data. In this case, the wireless communication terminal must wait until the next transmission opportunity in order to transmit a frame that does not transmit data. This can be very inefficient if the size of a frame that does not transmit data is very small. A method of solving this problem will be described with reference to FIGS. 20 through 25.

20 shows a form of an A-MPDU according to another embodiment of the present invention.

The A-MPDU may include not only frames for transmitting data but also other types of frames. In more detail, the A-MPDU may include a control frame for controlling data transmission, a management frame for network operation, and a frame for transmitting feedback information. The control frame may include at least one of a frame indicating whether data is received, a Request To Send (RTS) frame, a Clear To Send (CTS) frame, and a trigger frame. The frame indicating whether data is received may include at least one of the above-described ACK frame, BA frame, and M-BA frame.

According to a specific embodiment, the wireless communication terminal may transmit a frame not transmitting data positioned behind a frame transmitting data in the A-MPDU. For example, the wireless communication terminal may transmit a frame not transmitting data to be located in the last MPDU in the A-MPDU. This is because an MPDU delimiter may be additionally used when the size of a frame that does not transmit data is small and positioned between the frames that transmit data. According to another specific embodiment of the present disclosure, the wireless communication terminal may transmit a frame not transmitting data in front of a frame transmitting data in the A-MPDU. For example, the wireless communication terminal may transmit a frame not transmitting data to be located in the first MPDU in the A-MPDU. Through this location setting, the processing speed for a frame not transmitting data of the wireless communication terminal can be increased.

In the case of a frame for transmitting data, the wireless communication terminal should extract the MSDU from the MPDU and deliver it to the LLC layer. In the case of a frame not transmitting data, the wireless communication terminal performs an operation according to the MPDU in the MAC layer. Therefore, when the A-MPDU includes not only a frame for transmitting data but also other types of frames, the wireless communication terminal receiving the A-MPDU should efficiently distinguish between a frame for transmitting data and a frame for not transmitting data. This will be described with reference to FIGS. 21 to 24.

21 shows a MAC header according to an embodiment of the present invention. 22 shows a MAC header of an MPDU included in an A-MPDU according to another embodiment of the present invention.

The wireless communication terminal may identify a frame transmitting data and a frame not transmitting data based on the MAC header in the A-MPDU. In more detail, the wireless communication terminal may identify a frame transmitting data and a frame not transmitting data based on the Type field and the Subtype field of the MAC header in the A-MPDU. According to a specific embodiment, in the case of a frame for transmitting data, the value of the Type field may be zero. In addition, when the frame does not transmit data, the value of the Type field may be 1. In addition, the subtype field may indicate the detailed type of the frame. The specific format of the MAC header may be as shown in FIG. 21.

In this case, the wireless communication terminal transmitting the A-MPDU sets the value of the MAC header according to whether or not it is a frame for transmitting data. In more detail, the wireless communication terminal transmitting the A-MPDU may set a value of the Type field of the MAC header according to whether the frame transmits data. In this case, however, the wireless communication terminal receiving the A-MPDU may know whether the frame transmits data only after parsing the MAC header. Therefore, after parsing MAC headers of all MPDUs, the operation of the corresponding MPDUs is determined. A specific embodiment will be described with reference to FIG. 22.

In the embodiment of FIG. 22, the wireless communication terminal receiving the A-MPDU must parse the headers of the first, second, and third MPDUs, so that the first, second, and third MPDUs transmit data. It can be seen. In addition, the wireless communication terminal receiving the A-MPDU needs to parse the header of the fourth MPDU, so that the fourth MPDU can know the frame in which the control frame is transmitted.

As such, when identifying a frame for transmitting data and a frame for not transmitting data based on the MAC header, the wireless communication terminal parses the MAC header of the MPDU, and thus the type of the corresponding MPDU is known. A-MPDU processing performance may be impaired. Therefore, there is a need for a solution to this. This will be described with reference to FIGS. 23 to 25.

23 illustrates an MPDU delimiter structure included in an A-MPDU according to an embodiment of the present invention. 24 is a view illustrating an MPDU delimiter structure included in an A-MPDU according to another embodiment of the present invention.

The MPDU delimiter may include an EoF field indicating the last MPDU. In a specific embodiment, the EoF field may be a 1-bit field.

In addition, the MPDU delimiter may include a reserved field reserved for future use. According to a specific embodiment, the reserved field may be a 1-bit field.

In addition, the MPDU delimiter may include an MPDU Length field indicating the length of the MPDU. In a specific embodiment, the MPDU Length field may be a 14-bit field.

In addition, the MPDU delimiter may include a CRC field for determining whether an MPDU contains an error. According to a specific embodiment, the CRC field may be an 8-bit field.

In addition, the MPDU delimiter may include a Delimiter Signature field to indicate that the MPDU delimiter. In a specific embodiment, the Delimiter Signature field may be an 8-bit field.

At this time, the form of the specific MPDU delimiter may be the same as FIG.

According to another embodiment, the MPDU delimiter may include a field indicating whether the MPDU transmits data. For convenience of description, a field indicating whether the MPDU transmits data is referred to as a non-MSDU field. In more detail, the Non-MSDU field may indicate that the MPDU is used only in the MAC layer because it does not include the MSDU. In addition, the Non-MSDU field may be a 1-bit field. For example, when the value of the Non-MSDU field is 1, this may indicate that the corresponding MPDU is not an MPDU for transmitting data. In this case, the MPDU other than the MPDU for transmitting data may be at least one of a control frame, a management frame, and a frame for transmitting feedback information as described above. In addition, the Non-MSDU field may be included instead of the reserved bit described above. In this case, the specific format of the MPDU delimiter may be the same as FIG. 24.

In a specific embodiment, the wireless communication terminal transmitting the A-MPDU sets a value of the Non-MSDU field according to whether the MPDU transmits data. The wireless communication terminal transmitting the A-MPDU transmits the A-MPDU including the MPDU delimiter including the Non-MSDU field.

At this time, the wireless communication terminal receiving the A-MPDU determines whether the MPDU to transmit data based on the MPDU delimiter. In more detail, the wireless communication terminal receiving the A-MPDU may determine whether the MPDU transmits data based on the Non-MSDU field included in the MPDU delimiter. According to a specific embodiment of the present invention, the wireless communication terminal receiving the A-MPDU acquires the value of the non-MSDU field and determines whether the data is an MPDU based on the value of the non-MSDU field.

As described above, the A-MPDU may include an MPDU that does not transmit data. In this case, the MPDU not transmitting data may be a frame for transmitting feedback information. This will be described in detail with reference to FIG. 25.

25 is a view illustrating a wireless communication terminal transmitting various information through an A-MPDU according to an embodiment of the present invention.

The second wireless communication terminal may transmit feedback information indicating information related to data transmission of the first wireless communication terminal of the second wireless communication terminal to the first wireless communication terminal through the A-MPDU. When the feedback information is transmitted through the A-MPDU, the second wireless communication terminal can quickly transmit the feedback information to the first wireless communication terminal. This is because the second wireless communication terminal does not go through a separate competition procedure for transmitting the feedback information.

In more detail, the feedback information may include availability of frequency bands detected by the second wireless communication terminal. In this case, the frequency band may be a resource unit (RU) indicating a frequency band allocated by the first wireless communication terminal to the second wireless communication terminal. In addition, the feedback information may include a signal level for each frequency band detected by the second wireless communication terminal. In this case, the frequency band may be a resource unit indicating a frequency band allocated by the first wireless communication terminal to the second wireless communication terminal. In addition, the feedback information may include a buffer state of the second wireless communication terminal. In this case, the buffer state may indicate at least one of the size and the number of data waiting to be transmitted by the second wireless communication terminal. In addition, the feedback information may include information about the BSS adjacent to the second wireless communication terminal.

In addition, the second wireless communication terminal may transmit valid time information indicating a period during which the feedback information is available to the first wireless communication terminal. This is because the information represented by the feedback information may change over time. Also, in a specific embodiment, the feedback information may be divided into a plurality of types, and the valid time information of the feedback information may be determined based on the type of the feedback information. For example, the feedback information may have different valid times according to the type of the feedback information. Information related to the state of the frequency band may have a relatively short valid time. For example, the information related to the state of the frequency band may have a shorter valid time than the information about the adjacent BBS. In addition, the information related to the state of the frequency band may have a shorter valid time than the information related to the buffer state. In this case, the information related to the state of the frequency band may include a signal level for each frequency band detected by the second wireless communication terminal. In addition, the information related to the state of the frequency band may include whether or not available for each frequency band detected by the second wireless communication terminal.

The first wireless communication terminal can allocate resources based on the feedback information transmitted by the second wireless communication terminal. In this case, the resource may include at least one of a frequency band to receive the second wireless communication terminal, a transmission time of the second wireless communication terminal, and TXOP.

In FIG. 25, the first station STA1 to the third station STA3 transmit various feedback information to the AP through A-MPDUs (UL-Data1 to UL-Data3).

The AP allocates resources to the first station STA1 to the third station STA3 based on the feedback information transmitted from the first station STA1 to the third station STA3.

In this case, the first station STA1 transmits to the AP whether the frequency band detected by the first station STA1 is available. However, information on whether the frequency band detected by the first station STA1 transmitted by the first station STA1 has a validity period is valid. Therefore, as time passes, the information about the availability of the frequency band becomes invalid.

Accordingly, the AP is based on the feedback information transmitted from the first station STA1 to the third station STA3 except for the availability of the frequency band transmitted by the first station STA1. ) To the third station STA3. Since the AP has various feedback information, an optimal resource can be allocated to the first station STA1 to the third station STA3. For example, the AP may allocate an optimal TXOP to the first station STA1 to the third station STA3.

The first station STA1 to the third station STA3 transmit data to the AP according to resources allocated by the AP.

Through this operation, data transmission efficiency of the second wireless communication terminal with respect to the first wireless communication terminal can be improved.

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 invention.

The plurality of second wireless communication terminals 500 transmits data to the first wireless communication terminal 400 (S2601). As described above, the plurality of second wireless communication terminals 500 may transmit data to the first wireless communication terminal 400 through OFDMA or MU-MIMO. In this case, each of the plurality of second wireless communication terminals may transmit data to the first wireless communication terminal 400 through the A-MPDU described above.

In this case, the first wireless communication terminal 400 and the second wireless communication terminal 500 may prevent a transmission collision between the first wireless communication terminal 400 and the hidden wireless communication terminal through various embodiments.

The second wireless communication terminal 500 based on the information for limiting the size of the frame indicating whether or not to receive the data transmitted by each of the plurality of second wireless communication terminal 500 to the plurality of second wireless communication terminal 500. Data can be transferred. To this end, the first wireless communication terminal 400 may transmit information for limiting the size of a frame indicating whether or not the data transmitted by each of the second wireless communication terminals 500 is received to the second wireless communication terminal 500. Specifically, the second wireless communication terminal 500 may transmit data based on the maximum value of the number of data identifiers designated by the first wireless communication terminal. The data identifier is an identifier for identifying data transmitted by the plurality of second wireless communication terminals 500. In addition, the data identifier may indicate at least one of an identifier of the TID and the second wireless communication terminal. In addition, as the number of data identifiers increases, the size of a frame indicating whether or not to receive data transmitted by each of the plurality of second wireless communication terminals 500 increases.

The second wireless communication terminal 500 may transmit data including a number of identifiers smaller than or equal to the maximum value of the number of data identifiers designated by the first wireless communication terminal 400. In more detail, the second wireless communication terminal 500 may transmit data based on the maximum number of TIDs designated by the first wireless communication terminal 400. For example, the second wireless communication terminal 500 may transmit a plurality of MPDUs having a number of TIDs less than or equal to the maximum number of TIDs designated by the first wireless communication terminal 400. In addition, the second wireless communication terminal 500 may transmit data based on the maximum number of second wireless communication terminals 500 designated by the first wireless communication terminal 400.

In addition, the first wireless communication terminal 500 may limit the number of data identifiers transmitted by the second wireless communication terminal based on the hidden waiting time as described with reference to the embodiments of FIGS. 7 to 8.

In addition, the first wireless communication terminal may transmit the number of data identifiers through a trigger frame. In this case, the second wireless communication terminal 500 may receive a trigger frame and obtain the number of data identifiers from the trigger frame.

In another specific embodiment, while the second wireless communication terminal 500 transmits data to the first wireless communication terminal 400, the second wireless communication terminal 500 transmits data to the first wireless communication terminal (L-SIG). TXOP may be set until the time of receiving the M-BA from 400). Specifically, the second wireless communication terminal 500 takes the value of the field indicating the duration of the physical frame of the L-SIG for the second wireless communication terminal 500 to receive the M-BA from the first wireless communication terminal 400. It can be set up to the time. Since the plurality of second wireless communication terminals 500 receive the M-BA from the first wireless communication terminal 400, the time of the TXOP set by the plurality of second wireless communication terminals 500 through the L-SIG field is May be the same. In addition, the specific TXOP setting time may be the same as the embodiments described with reference to FIGS. 12 to 17.

In addition, the plurality of second wireless communication terminals 500 may transmit data to the first wireless communication terminal 400 through the A-MPDU. At this time, the A-MPDU indicates that the physical layer transmits a plurality of MAC Protocol Data Units (MPDUs) to one PLCU Service Data Unit (PSDU) as described above. The plurality of MPDUs may include a first MPDU for transmitting data and a second MPDU for not transmitting data. In addition, the A-MPDU may include an MPDU delimiter for dividing a boundary between a plurality of MPDUs, and the MPDU delimiter may include a field for identifying the first MPDU and the second MPDU.

The second MPDU may be at least one of a control frame, a management frame, and a frame for transmitting feedback information. In more detail, the feedback information may include availability of frequency bands detected by the wireless communication terminal. In this case, the frequency band may be a resource unit (RU) indicating a frequency band allocated by the first wireless communication terminal 400 to the second wireless communication terminal 500. In addition, the feedback information may include a signal level for each frequency band detected by the second wireless communication terminal 500. In this case, the frequency band may be a resource unit indicating a frequency band allocated by the first wireless communication terminal 400 to the second wireless communication terminal 500. In addition, the feedback information may include a buffer state of the second wireless communication terminal 500. In this case, the buffer state may indicate at least one of the size and the number of data waiting to be transmitted from the second wireless communication terminal 500. In addition, the feedback information may include information about the BSS adjacent to the second wireless communication terminal 500.

In addition, the second wireless communication terminal 500 may transmit valid time information indicating a period during which the feedback information is available to the first wireless communication terminal 400. Also, in a specific embodiment, the feedback information may be divided into a plurality of types, and the valid time information of the feedback information may be determined based on the type of the feedback information. For example, the feedback information may have different valid times according to the type of the feedback information. Information related to the state of the frequency band may have a relatively short valid time. For example, the information related to the state of the frequency band may have a shorter valid time than the information about the adjacent BBS. In addition, the information related to the state of the frequency band may have a shorter valid time than the information related to the buffer state. In this case, the information related to the state of the frequency band may include a signal level for each frequency band detected by the second wireless communication terminal 500. In addition, the information related to the state of the frequency band may include whether or not available for each frequency band detected by the second wireless communication terminal 500.

In another specific embodiment, the first wireless communication terminal 400 may change the transmission power when transmitting the M-BA. In more detail, the first wireless communication terminal 400 may use a larger transmission power than other cases when transmitting the M-BA. For example, when transmitting the M-BA, the first wireless communication terminal 400 may use a larger transmission power than when transmitting data. In another specific embodiment, the first wireless communication terminal 400 may increase the transmission power for transmitting the M-BA according to the length of the M-BA. Specifically, when the length of the M-BA is greater than or equal to the reference value, the first wireless communication terminal 400 may increase the transmission power for transmitting the M-BA.

The first wireless communication terminal 400 transmits a frame indicating whether the data transmitted by each of the plurality of second wireless communication terminals 500 is received to the plurality of second wireless communication terminals 500 (S2603). In this case, the frame indicating whether the data transmitted by each of the plurality of second wireless communication terminals 500 is received may be the aforementioned M-BA.

Although 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. In addition, while 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.

Features, structures, effects, and the like described in the above embodiments are included in at least one embodiment of the present invention, and are not necessarily limited to only one embodiment. Furthermore, the features, structures, effects, and the like illustrated in the embodiments may be combined or modified with respect to other embodiments by those skilled in the art to which the embodiments belong. Therefore, contents related to such combinations and modifications should be construed as being included in the scope of the present invention.

Although the above description has been made with reference to the embodiments, these are merely examples and are not intended to limit the present invention. Those skilled in the art to which the present invention pertains are not illustrated above without departing from the essential characteristics of the present embodiments. It will be appreciated that many variations and applications are possible. For example, each component specifically shown in the embodiment can be modified. And differences relating to such modifications and applications will have to be construed as being included in the scope of the invention defined in the appended claims.

Claims (20)

In a wireless communication terminal wirelessly communicating with the base wireless communication terminal, RF transceiver for transmitting and receiving a wireless signal; And And a demodulation demodulator for modulating and demodulating the radio signal. The RF transceiver Transmitting a radio signal including data to the base radio communication terminal; The variation demodulation unit A first frame is demodulated from a radio signal received from the base radio communication terminal, and the first frame indicates whether or not to receive data transmitted by each of a plurality of radio communication terminals including the radio communication terminal. Wireless communication terminal. In claim 1, The variation demodulation unit Modulating data to be transmitted to the base wireless communication terminal based on the maximum value of the number of data identifiers designated by the base wireless communication terminal, The data identifier is An identifier for identifying data transmitted by the plurality of wireless communication terminals. Wireless communication terminal. In claim 2, The maximum value of the number of data identifiers specified by the base wireless communication terminal indicates the maximum value of the number of traffic identifiers (TIDs). Wireless communication terminal. In claim 2, The maximum value of the number of data identifiers designated by the base wireless communication terminal indicates the maximum value of the number of the plurality of wireless communication terminals. Wireless communication terminal. In claim 2, The variation demodulation unit Demodulate a second frame from a radio signal transmitted by the base wireless communication terminal, obtain a maximum value of the number of data identifiers from the second frame, The second frame Represents information about a resource allocated to each of the plurality of wireless communication terminals. Wireless communication terminal. In claim 2, When the number of data identifiers increases, the size of the first frame increases. Wireless communication terminal. In claim 1, The variation demodulation unit Modulate an Aggregate-MAC Protocol Data Unit (A-MPDU) transmitted to a base wireless communication terminal, and the A-MPDU transmits a plurality of MPDUs to one PSDU (PLCP Service Data Unit) in the physical layer, The plurality of MPDUs are A first MPDU that transmits data and a second MPDU that does not transmit data Wireless communication terminal. In claim 7, The A-MPDU is An MPDU delimiter for dividing a boundary between the plurality of MPDUs; The MPDU Delimiter And a field identifying the first MPDU and the second MPDU. Wireless communication terminal. In claim 7, The second MPDU is It includes feedback information indicating the information on the data transmission from the wireless communication terminal to the base wireless communication terminal Wireless communication terminal. In claim 9, The feedback information is Includes information about a buffer state of the wireless communication terminal, The buffer state of the wireless communication terminal indicates at least one of the size and the number of data waiting to be transmitted by the wireless communication terminal. Wireless communication terminal. In claim 9, The variation demodulation unit Modulating valid time information indicating a period during which the feedback information can be used; Wireless communication terminal. In claim 9, The feedback information is Divided into multiple types, The valid time information is determined based on the plurality of types. Wireless communication terminal. In a base wireless communication terminal that communicates wirelessly with a plurality of wireless communication terminals, RF transceiver for transmitting and receiving a wireless signal; And And a demodulation demodulator for modulating and demodulating the radio signal. The RF transceiver Receive a radio signal received from each of the plurality of radio communication terminals and including data; The variation demodulation unit Modulating a first frame indicating whether each of the plurality of wireless communication terminals receives data transmitted to the plurality of wireless communication terminals; Base wireless communication terminal. In claim 13, The variation demodulation unit The plurality of wireless communication terminals to transmit to each of the plurality of wireless communication terminals modulate a maximum value of the number of data identifiers, Each of the plurality of wireless communication terminals Transmit data to the base wireless communication terminal based on the maximum value of the number of data identifiers, The data identifier is An identifier for identifying data transmitted by the plurality of wireless communication terminals. Base wireless communication terminal. The method of claim 14, The maximum value of the number of data identifiers indicates the maximum value of the number of traffic identifiers (TIDs). Base wireless communication terminal. The method of claim 14, The maximum value of the number of data identifiers represents the maximum value of the number of the plurality of wireless communication terminals. Base wireless communication terminal. The method of claim 14, The variation demodulation unit Modulating a second frame transmitting the maximum value of the number of data identifiers, The second frame Represents information about a resource allocated to each of the plurality of wireless communication terminals. Base wireless communication terminal. The method of claim 14, When the number of data identifiers increases, the size of the first frame increases. Base wireless communication terminal. In claim 13, The variation demodulation unit A-MPDU (Aggregate-MAC Protocol Data Unit) is demodulated from a radio signal received from any one of the plurality of wireless communication terminals, and the A-MPDU is a plurality of MAC Protocol Data Units (MPDUs) in the physical layer. Transmitted to PSDU (PLCP Service Data Unit), The plurality of MPDUs are A first MPDU for transmitting data and a second MPDU for not transmitting data; The second MPDU is It includes feedback information indicating information on the data transmission for the base wireless communication terminal of each of the plurality of wireless communication terminal Base wireless communication terminal. In the operation method of the wireless communication terminal, Transmitting data to the base wireless communication terminal; And Receiving a first frame indicating whether data received by each of a plurality of wireless communication terminals including the wireless communication terminal is received from the base wireless communication terminal; How it works.

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