KR102557239B1 - Communication apparatus and method of transmitting data frame - Google Patents

Abstract

A data frame transmission method of a communication device is disclosed. In one embodiment, when another communication device occupies the channel, it is determined whether a transmittable condition of the data frame of the communication device is satisfied, and based on the determination, an end time of another data frame transmitted by the other communication device is checked, and the data frame is transmitted based on the confirmed end time point.

Description

Communication device and data frame transmission method of communication device {COMMUNICATION APPARATUS AND METHOD OF TRANSMITTING DATA FRAME}

The following embodiments relate to the MAC protocol of a wireless LAN and to a method for two or more devices to simultaneously transmit data in an overlapping Basic Service Set (BSS) environment.

As the recent wireless LAN environment becomes complex, a basic service set (BSS), which is a service area of an access point, overlaps with a basic service set of another access point (Overlapped BSS, OBSS) may occur. Due to OBSS, transmission efficiency of BSS may be degraded.

US Patent Publication US 2012/0257574 (Title of Invention: Method for reducing interference between base stations in a wireless LAN system and its apparatus (METHOD OF REDUCING INTERFERENCE BETWEEN STATIONS IN WIRELESS LAN SYSTEM, AND APPARATUS SUPPORTING THE SAME), Applicant: LG Electronics).

Embodiments may provide a technique for increasing transmission efficiency of a BSS in an OBSS environment. Also, according to embodiments, two or more communication devices may simultaneously transmit data in an OBSS environment. In addition, in the embodiments, two or more communication devices can simultaneously transmit data in a wireless LAN environment including communication devices capable of simultaneously transmitting and receiving data through the same channel.

A method of transmitting a data frame according to one aspect includes determining whether a transmission possibility condition of a data frame of a communication device is satisfied when another communication device occupies a channel; based on the determination, checking an end point of another data frame transmitted by the other communication device; and transmitting the data frame based on the confirmed end time point.

The step of determining whether the transmittable condition is satisfied may be a step of determining whether the transmittable condition is satisfied based on whether a request to send (RTS) transmitted by the other communication device and a clear to send (CTS) corresponding to the RTS are each heard.

The step of determining whether the transmittable condition is satisfied may include setting a Network Allocation Vector (NAV) based on the listening of the RTS; initializing the NAV when the CTS is not listened to; and determining that transmission of the data frame of the communication device is possible based on the initialization.

The checking of the end time of the other data frame may include listening to the other data frame and checking length information of the other data frame based on the listening.

The data frame transmission method may further include generating the data frame so that the checked end time and the end time of the data frame coincide.

The generating of the data frame may include adjusting a length of the data frame when the checked end time and the end time of the data frame do not match.

The communication device may be a first access point, and the other communication device may be a terminal located in an area where a service area of a second access point connected to the other communication device and a service area of the first access point overlap.

The other communication device may be an access point capable of simultaneously transmitting data frames and receiving data frames on the channel.

A method of transmitting a data frame according to another aspect includes determining whether another communication device can transmit a data frame with another communication device in a state where the other communication device occupies a channel; and transmitting the data frame so that an end time of another data frame transmitted by the other communication device coincides with an end time of the data frame transmitted by the communication device, based on the determination.

The step of determining whether data frame transmission with the other communication device is possible may include setting a Network Allocation Vector (NAV) based on listening to a request to send (RTS) transmitted by the other communication device; and initializing the NAV when a clear to send (CTS), which is a response to the RTS, is not listened to.

The transmitting of the data frame may include: listening to the other data frame and checking length information of the other data frame based on the listening; and generating the data frame using the length information.

Transmitting the data frame may include adjusting a length of the data frame when an end time of the other data frame and an end time of the data frame do not match.

A communication device according to one side determines whether a transmittable condition of a data frame of the communication device is satisfied when another communication device occupies a channel, and based on the determination, a processor configured to determine an end point of another data frame transmitted by the other communication device; and a transmitter transmitting the data frame based on the confirmed end time point.

In an OBSS environment, two or more communication devices can simultaneously transmit data, so transmission efficiency in the OBSS environment can be increased. In addition, even in a wireless LAN environment including communication devices capable of simultaneously transmitting and receiving data through the same channel, two or more communication devices can simultaneously transmit data, thereby increasing transmission efficiency.

1 is a diagram for explaining an example of a wireless network environment.
2 is a diagram for explaining the operation of a communication device in the wireless network environment of FIG. 1;
FIG. 3 is a diagram for explaining an operation of a communication device according to an embodiment in the wireless network environment of FIG. 1 .
4 is a diagram for explaining a data frame transmitted by a communication device according to an exemplary embodiment.
FIG. 5 is a diagram for explaining VHT-SIG-A of the data frame of FIG. 4 .
6 is a diagram for explaining another example of a wireless network environment.
FIG. 7 is a diagram for explaining an operation of a communication device according to an embodiment in the wireless network environment of FIG. 6 .
8 is a flowchart illustrating a data frame transmission method of a communication device according to an exemplary embodiment.
9 is a block diagram illustrating a communication device according to an exemplary embodiment.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings.

Various changes may be made to the embodiments described below. The embodiments described below are not intended to be limiting on the embodiments, and should be understood to include all modifications, equivalents or substitutes thereto.

Terms used in the examples are used only to describe specific examples, and are not intended to limit the examples. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, terms such as "comprise" or "having" are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, but it should be understood that the presence or addition of one or more other features or numbers, steps, operations, components, parts, or combinations thereof is not excluded in advance.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the art to which the embodiment belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and are not interpreted in an ideal or excessively formal sense unless explicitly defined herein.

In addition, in the description with reference to the accompanying drawings, the same reference numerals are given to the same components regardless of reference numerals, and overlapping descriptions thereof will be omitted. In describing the embodiment, if it is determined that a detailed description of a related known technology may unnecessarily obscure the gist of the embodiment, the detailed description will be omitted.

1 is a diagram for explaining an example of a wireless network environment.

Referring to FIG. 1 , a terminal 120 is connected to an access point 110 and a terminal 140 is connected to an access point 130 . That is, the terminal 120 may be located in the service area 111 of the access point 110, and the terminal 140 may be located in the service area 131 of the access point 130.

The service area 111 or 131 is referred to as a Basic Service Set (BSS).

The service area 111 of the access point 110 and the service area 131 of the access point 130 may overlap, and the terminal 120 may be located in the overlapping area 150 . The overlapping region 150 is referred to as an overlapped BSS (OBSS). The terminal 120 can listen to packets transmitted by the access point 110 and packets transmitted by the access point 130 . In addition, the access point 130 may listen to packets transmitted by the terminal 120 and packets transmitted by the terminal 140.

2 is a diagram for explaining the operation of a communication device in the wireless network environment of FIG. 1;

The access point 110 of FIG. 1 corresponds to the access point 210 of FIG. 2 , and the access point 130 of FIG. 1 corresponds to the access point 230 of FIG. 2 . Also, the terminal 120 of FIG. 1 corresponds to the terminal 220 of FIG. 2 , and the terminal 140 of FIG. 1 corresponds to the terminal 240 of FIG. 2 .

Referring to FIG. 2 , when the channel is in an idle state, the terminal 220 and the access point 230 may perform random backoff. At this time, the terminal 220 and the access point 230 may perform random backoff for data frame transmission.

When the random backoff of the terminal 220 ends first, the terminal 220 may transmit a data frame to the access point 210 . The access point 230 may listen to a data frame transmitted from the terminal 220 to the access point 210 . For example, the access point 230 may listen to the Duration field included in the data frame.

The access point 230 may set a Network Allocation Vector (NAV) using a value included in the Duration field.

The Duration field may include a time interval from the start of the data frame to the end of the response to the data frame. In the example shown in FIG. 2 , the terminal 220 may transmit to the access point 210 a data frame in which a time interval from the start of Data 1 to the end of Ack 1 is set as a Duration field. The access point 230 may set the NAV until the end of Ack 1, which is a response to Data 1. Until the NAV is over, the access point 230 may treat the channel in a busy state. The access point 230 cannot transmit a data frame to the terminal 240 through the channel until the NAV ends.

In the example shown in FIG. 2 , the access point 230 cannot transmit a data frame to the terminal 240 due to channel occupation by the terminal 220 .

FIG. 3 is a diagram for explaining an operation of a communication device according to an embodiment in the wireless network environment of FIG. 1 .

The access point 110 of FIG. 1 corresponds to the access point 310 of FIG. 3 , and the access point 130 of FIG. 1 corresponds to the access point 330 of FIG. 3 . Also, the terminal 120 of FIG. 1 corresponds to the terminal 320 of FIG. 3 , and the terminal 140 of FIG. 1 corresponds to the terminal 340 of FIG. 3 .

The access point 310 and terminal 320 belong to a first BSS, and the access point 330 and terminal 340 belong to a second BSS. The terminal 320 is only located in an area where the first BSS and the second BSS overlap, and basically belongs to the first BSS.

In the wireless network environment of FIG. 1 , a communication device according to an embodiment may be an access point 330 .

Referring to FIG. 3 , when a channel is in an idle state, a terminal 320 and an access point 330 may perform random backoff. At this time, the terminal 320 and the access point 330 may perform random backoff for data frame transmission.

If the random backoff of the terminal 320 ends first, the terminal 320 may occupy the channel. In addition, the terminal 320 may transmit a request to send (RTS) 321 to the access point 310, and the access point 310 may transmit a clear to send (CTS) 311 to the terminal 320 in response to the RTS 321. The terminal 320 may transmit a data frame 322 to the access point 310 after receiving the CTS 311 .

The access point 330 can listen to packets transmitted by the terminal 320, but cannot listen to packets transmitted by the access point 310. Among communication devices belonging to another BSS, that is, the second BSS, the access point 330 can listen to the RTS 321 and cannot listen to the CTS 311. Access point 330 and access point 310 are in a state where they cannot listen to each other.

The access point 330 may set the NAV based on listening of the RTS 321 . Access point 330 may treat the channel as a busy state. Since the access point 330 cannot listen to the CTS 311 transmitted by the access point 310, it can initialize the NAV. Since the access point 330 and the access point 310 are in a state where they cannot listen to each other, the access point 330 and the communication device (i.e., terminal 320) that transmitted the RTS 321 can confirm that their data frames can be simultaneously transmitted to the target. Here, the target of the access point 330 is the terminal 340, and the target of the terminal 320 is the access point 310. The above-described meaning of “simultaneously” is not construed as limiting that the access point 330 transmits a data frame at the same time as the terminal 320. The access point 330 may consider a busy state of the channel as an available state of the channel.

The access point 330 may make the end time of the data frame 331 transmitted by itself the same as the end time of the data frame 322 transmitted by the terminal 320. Hereinafter, it demonstrates, referring FIG.

4 is a diagram for explaining a data frame transmitted by a communication device according to an exemplary embodiment.

The terminal 320 shown in FIG. 3 may transmit a data frame 400 to the access point 310 . The data frame 400 may include a plurality of fields. For example, the data frame 400 includes a legacy-short training field (L-STF) 410, a legacy-long training field (L-LTF) 420, a legacy-signal (L-SIG) 430, a very high throughput-signal-A (VHT-SIG-A) 440, a very high throughput-short training field (VHT-STF) 450, V It may include a Very High Throughput-Long Training Field (HT-LTF) 460, a Very High Throughput-Signal-B (VHT-SIG-B) 470, and Data 480.

L-SIG 430 may include a plurality of subfields. For example, L-SIG 430 may include L-DATARATE 431 , L-LENGTH 432 , Parity 433 , and Tail 434 .

The access point 330 may listen to the L-SIG 430 of the data frame 400 . The access point 330 may check the temporal length of the data frame 400 using L-DATARATE 431 and L-LENGTH 432 included in the L-SIG 430 . The access point 330 may calculate an end point of the data frame 400 transmitted by the terminal 320 based on the temporal length.

Returning to FIG. 3 again, the access point 330 may calculate the end point of the data frame 211 using the length of the data frame 322 transmitted by the terminal 320. The access point 330 may make the end time of the data frame 331 to be transmitted the same as the calculated end time. For example, the access point 330 may divide the data when the end time of the data frame 331 and the calculated end time do not coincide because the amount of data to be transmitted to the terminal 340 is large. In addition, the access point 330 may insert padding into the data frame 331 when the end time of the data frame 331 and the calculated end time do not match because the amount of data to be transmitted to the terminal 340 is small.

When the end time of the data frame 322 and the end time of the data frame 331 do not coincide, interference may occur, and the access point 330 and the terminal 320 cannot properly receive the Ack due to the interference. For example, when the transmission of the data frame 322 ends first and the transmission of the data frame 331 ends later, the transmission of the data frame 331 may act as interference to the terminal 320, and the terminal 320 cannot properly receive Ack 1 (312). The end time of the data frame 322 and the end time of the data frame 331 must coincide with each other so that an interference situation does not occur.

The access point 310 may transmit Ack 1 312 to the terminal 320 in response to the data frame 322, and the terminal 340 may transmit Ack 2 341 to the access point 330 in response to the data frame 331.

The time when transmission of the data frame 322 ends coincides with the time when transmission of the data frame 331 ends, and Ack 1 312 and Ack 2 341 may be simultaneously transmitted. The terminal 320 can listen to Ack 1 (312) and cannot listen to Ack 2 (341). The access point 330 cannot listen to Ack 1 (312) and can listen to Ack 2 (341).

In one embodiment, the access point 330 can confirm that the data frame 322 is not a data frame to be received by using a specific field of the data frame 322 transmitted by the terminal 320. Hereinafter, it demonstrates, referring FIG.

FIG. 5 is a diagram for explaining VHT-SIG-A of the data frame of FIG. 4 .

Referring to FIG. 5 , a VHT-SIG-A 500 of a data frame may include a plurality of subfields. For example, the VHT-SIG-A 500 may include a Group ID 510 and a Partial Association ID (AID) 520 and the like.

Using the group ID 510 and the partial AID 520, the access point 330 can confirm that the data frame 322 is not a data frame to be received by itself.

6 is a diagram for explaining another example of a wireless network environment.

Referring to FIG. 6 , a terminal 620 and a terminal 630 are located in a service area 611 of an access point 610 . Terminal 620 and terminal 630 can access the access point 610 . Terminal 620 and terminal 630 belong to the same BSS, but cannot listen to data frames transmitted by each other. That is, the terminal 620 cannot listen to the data frame transmitted by the terminal 630, and the terminal 630 cannot listen to the data frame transmitted by the terminal 620.

Access point 610 can simultaneously transmit and receive data on a channel. The access point 610 may support In Band Simultaneous Transmit and Receive (In Band STR). For example, the access point 620 may receive a data frame from the terminal 630 while transmitting the data frame to the terminal 620 through a channel.

FIG. 7 is a diagram for explaining an operation of a communication device according to an embodiment in the wireless network environment of FIG. 6 .

The access point 610 of FIG. 6 corresponds to the access point 710 of FIG. 7, the terminal 620 of FIG. 6 corresponds to the terminal 720 of FIG. 7, and the terminal 630 of FIG. 6 corresponds to the terminal 730 of FIG.

In the wireless network environment of FIG. 6 , a communication device according to an embodiment may be a terminal 730 .

Referring to FIG. 7 , when the channel is in an idle state, the access point 710 and the terminal 730 may perform random backoff. At this time, each of the access point 710 and the terminal 730 may perform a random backoff for transmission of its own data frame. Here, the access point 710 supports In-Band STR.

If access point 710's random backoff ends first, access point 710 may occupy the channel. In addition, the access point 710 may transmit a request to send (RTS) 711 to the terminal 720, and the terminal 720 may transmit a clear to send (CTS) 721 to the access point 710 in response to the RTS 711. The access point 710 may transmit a data frame 712 to the terminal 720 after receiving the CTS 721 .

Terminal 730 can listen to packets transmitted by access point 710, but cannot listen to packets transmitted by terminal 720. The terminal 730 can listen to the RTS 711 and cannot listen to the CTS 721. The terminal 720 and the terminal 730 are in a hidden state from each other.

When the terminal 730 listens to the RTS 711 and fails to listen to the CTS 721, the terminal 730 can confirm that it can transmit the data frame 731 to the access point 710. Since the access point 710 supports in-band STR, it can transmit the data frame 712 and receive the data frame 731 through the same channel.

The terminal 730 may listen to the data frame 712 transmitted by the access point 710. The terminal 730 may calculate an end point of the data frame 712 using a specific field of the data frame 712 . In addition, the terminal 730 may transmit the data frame 731 having the calculated end point to the access point 710 .

8 is a flowchart illustrating a data frame transmission method of a communication device according to an exemplary embodiment.

Each of the communication device and the other communication device may perform a random backoff to transmit its own data frame. In the case of the wireless network environment of FIG. 1, the communication device is the access point 2, and the other communication device is the terminal 1. In the case of the wireless network environment of FIG. 6, the communication device is terminal 2, and another communication device is an access point.

In the case of the wireless network environment of FIG. 1, a communication device, that is, access point 2, may perform a random backoff procedure to transmit a data frame to terminal 2 connected to it, and another communication device, that is, terminal 1 may perform a random backoff procedure to transmit a data frame to access point 1.

In the case of the wireless network environment of FIG. 6, a communication device, that is, terminal 2 may perform a random backoff procedure to transmit a data frame to an access point, and the access point may perform a random backoff procedure to transmit a data frame to terminal 1 accessing itself.

When the random backoff of the other communication device ends, the other communication device can occupy the channel. When another communication device occupies the channel, the communication device determines whether a transmission possibility condition of the data frame of the communication device is satisfied (810). In a state where another communication device occupies the channel, the communication device can determine whether it can simultaneously transmit a data frame with the other communication device.

For example, the communication device may determine whether a transmittable condition is satisfied based on whether each of a request to send (RTS) transmitted by another communication device and a clear to send (CTS) that is a response to the RTS is listened to. Another communication device may transmit an RTS to the target when occupying the channel. Here, the communication device may listen to the RTS, and when the communication device listens to the RTS, the communication device may set a Network Allocation Vector (NAV). When the communication device fails to listen to the CTS, it may initialize the NAV. Based on NAV initialization, the communication device may determine that the communication device itself can transmit the data frame even if another communication device occupies the channel.

When it is determined that the transmittable condition is satisfied, the communication device checks the end point of another data frame transmitted by another communication device (820). For example, the communication device may listen to another data frame and check length information of the other data frame based on the listening. The communication device may calculate a point in time when transmission of another data frame is completed by using length information of another data frame.

The communication device may generate a data frame such that an end time of another data frame coincides with an end time of a data frame to be transmitted by the communication device.

When the end time of another data frame and the end time of the data frame to be transmitted do not coincide, the communication device may adjust the length of the data frame. For example, the communication device may divide a specific field (eg, a data field) when the end time of a data frame and the end time of another data frame do not coincide due to a large amount of data to be transmitted. Through division of the data field, an end time of a data frame may coincide with an end time of another data frame. In addition, the communication device may insert padding into the data frame when the end time of a data frame and the end time of another data frame do not coincide because the amount of data to be transmitted is small. Padding bits may be added after the data field. An end time of a data frame may coincide with an end time of another data frame through insertion of padding.

The communication device transmits the data frame based on the confirmed end point (830).

The communication device may receive a first response to the data frame. Another communication device may receive a second response to another data frame. Since the end time of the data frame transmitted by the communication device and the end time of another data frame transmitted by the other communication device are the same, the transmission time of the first response and the transmission time of the second response may be the same. That is, the first response and the second response may be transmitted simultaneously. The communication device does not hear the second response and the other communication device does not listen to the first response.

Matters described through FIGS. 1 to 7 may be applied to matters described through FIG. 8 , and thus detailed descriptions thereof are omitted.

9 is a block diagram illustrating a communication device according to an exemplary embodiment.

Referring to FIG. 9 , a communication device 900 according to an embodiment includes a processor 910 and a transmitter 920.

When another communication device occupies the channel, the processor 910 determines whether a condition for transmitting a data frame of the communication device 900 is satisfied. The processor 910 may determine whether a transmittable condition is satisfied based on whether each of a request to send (RTS) transmitted by another communication device and a clear to send (CTS) that is a response to the RTS is listened to. For example, the processor 910 may set a Network Allocation Vector (NAV) based on RTS listening. Also, the processor 910 may initialize the NAV when the communication device 900 fails to listen to the CTS, and may determine that transmission of the data frame of the communication device 900 is possible based on the initialization.

When the transmittable condition is satisfied, the processor 910 checks the end point of another data frame transmitted by another communication device. For example, based on listening to other data frames, the length of another data frame can be ascertained. Also, the processor 910 may generate a data frame such that the checked end time and the end time of the data frame coincide. Here, when the checked end time and the end time of the data frame do not match, the processor 910 may adjust the length of the data frame to match the checked end time and the end time of the data frame. For example, the processor 910 may match the checked end time and the end time of the data frame by dividing data or inserting padding into the data frame.

The transmitter 920 transmits the data frame based on the confirmed end time point.

Matters described through FIGS. 1 to 8 may be applied to matters described through FIG. 9 , and thus detailed descriptions thereof are omitted.

The devices described above may be implemented as hardware components, software components, and/or a combination of hardware components and software components. For example, the devices and components described in the embodiments may be implemented using one or more general purpose or special purpose computers, such as, for example, a processor, controller, arithmetic logic unit (ALU), digital signal processor, microcomputer, field programmable gate array (FPGA), programmable logic unit (PLU), microprocessor, or any other device capable of executing and responding to instructions. A processing device may run an operating system (OS) and one or more software applications running on the operating system. A processing device may also access, store, manipulate, process, and generate data in response to execution of software. For convenience of understanding, there are cases in which one processing device is used, but those skilled in the art will recognize that the processing device may include a plurality of processing elements and/or multiple types of processing elements. For example, a processing device may include a plurality of processors or a processor and a controller. Other processing configurations are also possible, such as parallel processors.

Software may include a computer program, code, instructions, or a combination of one or more of these, and may configure a processing device to operate as desired, or may independently or collectively direct a processing device. Software and/or data may be permanently or temporarily embodied in any tangible machine, component, physical device, virtual equipment, computer storage medium or device, or transmitted signal wave, to be interpreted by, or to provide instructions or data to, a processing device. Software may be distributed on networked computer systems and stored or executed in a distributed manner. Software and data may be stored on one or more computer readable media.

The method according to the embodiment may be implemented in the form of program instructions that can be executed through various computer means and recorded on a computer readable medium. The computer readable medium may include program instructions, data files, data structures, etc. alone or in combination. Program commands recorded on the medium may be specially designed and configured for the embodiment or may be known and usable to those skilled in computer software. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks and magnetic tapes, optical media such as CD-ROMs and DVDs, magneto-optical media such as floptical disks, and hardware devices specially configured to store and execute program instructions such as ROM, RAM, and flash memory. Examples of program instructions include high-level language codes that can be executed by a computer using an interpreter, as well as machine language codes such as those produced by a compiler. The hardware devices described above may be configured to operate as one or more software modules to perform the operations of the embodiments, and vice versa.

As described above, although the embodiments have been described with limited examples and drawings, those skilled in the art can make various modifications and variations from the above description. For example, even if the described techniques are performed in an order different from the described method, and/or components of the described system, structure, device, circuit, etc. are combined or combined in a different form from the described method, or replaced or substituted by other components or equivalents, appropriate results can be achieved.

Therefore, other implementations, other embodiments, and equivalents of the claims are within the scope of the following claims.

Claims (10)

A data frame transmission method of a first communication device,
When listening to a Request To Send (RTS) transmitted by a second communication device occupying a channel, setting a Network Allocation Vector (NAV), considering the channel to be busy, and determining whether a simultaneous transmission condition regarding whether simultaneous data frame transmission with the second communication device is possible in a channel that the first communication device considers to be busy is satisfied;
Listening to a second data frame transmitted by the second communication device, and if the simultaneous transmission availability condition is satisfied, initializing the NAV to consider the channel considered busy as an available state, and checking an end time of the listened second data frame based on length information included in the listened second data frame; and
Generating the first data frame including a legacy signal field, a very high throughput (VHT) signal field, and a data field so that the end time of the first data frame of the first communication device coincides with the end time of the listened-to second data frame, and transmitting the generated first data frame to a third communication device.
including,
The time interval in which the generated first data frame is transmitted overlaps with the time interval in which the second data frame including a legacy signal field, a VHT signal field, and a data field is transmitted to a fourth communication device that is a communication target of the second communication device.
Data frame transmission method.
According to claim 1,
The determining step is
Determining that the simultaneous transmission possibility condition is satisfied when the first communication device listens to the RTS and fails to listen to a clear to send (CTS) of the fourth communication device
including,
Data frame transmission method.
According to claim 1,
the first communication device is a first access point;
The second communication device is a terminal,
Data frame transmission method.
According to claim 3,
The service area of the first access point and the service area of the second access point to which the second communication device is connected overlap, and the second communication device is located in the overlapped area.
Data frame transmission method.
According to claim 1,
The first communication device is a terminal,
The second communication device is an access point capable of simultaneously transmitting a data frame and receiving a data frame on the channel,
Data frame transmission method.
In the first communication device,
When listening to RTS (Request To Send) transmitted by the second communication device occupying the channel, NAV (Network Allocation Vector) is set, the channel is regarded as busy, and the first communication device simultaneously transmits data frames with the second communication device on the channel considered to be busy. Determines whether or not a simultaneous transmission possible condition is satisfied, listens for a second data frame transmitted by the second communication device, and satisfies the simultaneous transmission possible condition. A processor that initializes the NAV, considers the channel considered busy to be available, checks an end time of the listened second data frame based on length information included in the listened second data frame, and generates the first data frame including a legacy signal field, a Very High Throughput (VHT) signal field, and a data field so that the end time of the first data frame of the first communication device coincides with the end time of the listened second data frame; and
A transmitter for transmitting the generated first data frame to a third communication device
including,
The time interval in which the generated first data frame is transmitted overlaps with the time interval in which the second data frame including a legacy signal field, a VHT signal field, and a data field is transmitted to a fourth communication device that is a communication target of the second communication device.
A first communication device.
According to claim 6,
the processor,
When the first communication device listens to the RTS and fails to listen to the clear to send (CTS) of the fourth communication device, determining that the condition for simultaneous transmission is satisfied,
A first communication device.
According to claim 6,
the first communication device is a first access point;
The second communication device is a terminal,
A first communication device.
According to claim 8,
The service area of the first access point and the service area of the second access point to which the second communication device is connected overlap, and the second communication device is located in the overlapped area.
A first communication device.
According to claim 6,
The first communication device is a terminal,
The second communication device is an access point capable of simultaneously transmitting a data frame and receiving a data frame on the channel,
A first communication device.