Title of invention: Communication device
Technical field
[0001]
　The present technology relates to a communication device, and more particularly to a communication device capable of notifying surrounding devices of the existence of a device receiving data.
Background technology
[0002]
　Conventionally, in a wireless LAN system, when the use of a transmission line is grasped, a network allocation vector (NAV) is set from the value described in the Duration part of the MAC header, and control is performed to refrain from transmission from surrounding communication devices. It has been broken.
[0003]
　In the communication method using NAV, there are communication devices that exist in the vicinity of receiving the Request to Send (RTS) frame from the communication device on the data transmission side and the Clear to Send (CTS) frame from the communication device on the data reception side. , The configuration was such that the transmission line was used for the time described in the Duration part of the MAC header.
[0004]
　Further, conventionally, a method of transmitting a busy tone signal from an access point has been generally used as a method of notifying that a transmission line is in use.
[0005]
　The method using a busy tone signal is a state in which communication within one's own access point cannot be established due to a signal from a wireless communication terminal under the control of surrounding access points in an environment where multiple access points exist adjacent to each other. This is a method to prevent by transmitting a busy tone signal.
[0006]
　According to Patent Document 1, in an environment in which a plurality of access points are adjacent to each other, an access point using a transmission line transmits a busy tone signal using a predetermined tone channel, and is in use. A technology that conveys something to other access points is disclosed.
Prior art literature
Patent documents
[0007]
Patent Document 1: Japanese Unexamined Patent Publication No. 2011-254319
Outline of the invention
Problems to be solved by the invention
[0008]
　In the conventional NAV setting method, since it is set both when the RTS frame is received and when the CTS frame is received, transmission from a range that does not affect the reception of the data frame of the communication device on the receiving side is suppressed. It may end up.
[0009]
　Further, in the conventional method using a busy tone signal, it is necessary to prepare a communication block for transmitting and receiving the busy tone signal in the communication device.
[0010]
　The present technology has been made in view of such a situation, and can notify the surrounding devices of the existence of the device during data reception.
Means to solve problems
[0011]
　The communication device of the first aspect of the present technology includes a construction unit that generates a data frame, a transmission unit that transmits the data frame to a communication device at a transmission destination, and a transmission unit that transmits the data frame for a predetermined period of time during transmission. It is provided with a control unit that controls interruption.
[0012]
　The communication device of the second aspect of the present technology utilizes a receiving unit that receives a transmitted data frame with an intermittent period for interrupting transmission and a transmission line during the period for interrupting the transmission. It is provided with a transmission unit that transmits an in-use signal indicating that the device is in use.
[0013]
　In the communication device of the third aspect of the present technology, the data is interrupted during the period during which the transmission is interrupted with respect to the first communication device that transmits the transmitted data frame with an intermittent period for interrupting the transmission. A receiving unit that receives an in-use signal indicating that the transmission line is being used, which is transmitted from a second communication device that receives a frame, and a transmission control that controls transmission according to the reception status of the in-use signal. It has a part.
[0014]
　In the first aspect of the present technology, a data frame is generated, the data frame is transmitted to a communication device of a transmission destination, and control is performed to interrupt the transmission for a predetermined period during the transmission of the data frame.
[0015]
　In the second aspect of the present technology, a period for interrupting transmission is provided intermittently to indicate that the transmitted data frame is received and the transmission line is used during the period for interrupting the transmission. A medium signal is transmitted.
[0016]
　In the third aspect of the present technology, the data frame is provided during the period during which the transmission is interrupted to the first communication device that transmits the transmitted data frame with a period during which the transmission is interrupted. An in-use signal indicating that the transmission line is being used is received, which is transmitted from the second communication device to be received. Then, the transmission is controlled according to the reception status of the signal in use.
Effect of the invention
[0017]
　According to the present technology, it is possible to notify surrounding devices of the existence of a device that is receiving data.
[0018]
　It should be noted that the effects described in the present specification are merely examples, and the effects of the present technology are not limited to the effects described in the present specification, and may have additional effects.
A brief description of the drawing
[0019]
[Fig. 1] Fig. 1 is a diagram showing a configuration example of a wireless network of a wireless LAN system.
FIG. 2 is a diagram showing an interference situation of a wireless network when transmission power control is performed.
[Fig. 3] Fig. 3 is a diagram showing a malfunction of a wireless network when transmission power control is performed.
[Fig. 4] Fig. 4 is a diagram showing an operation example of surrounding communication devices when a CTS frame is transmitted on the receiving side.
[Fig. 5] Fig. 5 is a diagram showing a configuration example of a wireless LAN system of the present technology.
FIG. 6 is a diagram showing a state in which a reception error occurs when conventional transmission power control is performed.
[Fig. 7] Fig. 7 is a diagram showing an example of communication control using a signal in use by this technology.
[Fig. 8] Fig. 8 is a block diagram showing a configuration example of a communication device to which this technology is applied.
[Fig. 9] Fig. 9 is a block diagram showing a configuration example of a wireless communication module.
[Fig. 10] Fig. 10 is a diagram showing a configuration example of an A-MPDU frame.
FIG. 11 is a diagram showing an example of an A-MPDU frame configuration used in the present technology.
[Fig. 12] Fig. 12 is a diagram showing an example of a frame configuration of a signal in use.
[Fig. 13] Fig. 13 is a diagram showing an example of a frame configuration of End Signal.
[Fig. 14] Fig. 14 is a diagram showing an example of data arrangement of L-SIG and Using Signal parameters.
FIG. 15 is a diagram showing an example of a subcarrier configuration of an OFDM signal.
FIG. 16 is a diagram showing a relationship between a modulation method and a coding rate.
[Fig. 17] Fig. 17 is a diagram showing a configuration example of a preamble.
[Fig. 18] Fig. 18 is a diagram showing a configuration example of an L-SIG field.
FIG. 19 is a diagram showing a configuration example of an A-MPDU.
FIG. 20 is a diagram showing a detailed configuration example of one MPDU.
FIG. 21 is a diagram showing a configuration example of an MPDU delimiter.
FIG. 22 is a diagram showing an example of an internal configuration of an MPDU.
[Fig. 23] Fig. 23 is a diagram showing a configuration example of padding.
FIG. 24 is a flowchart illustrating a processing example of a communication device on the transmitting side.
FIG. 25 is a flowchart illustrating a processing example of a communication device on the receiving side.
FIG. 26 is a flowchart illustrating a processing example of a surrounding communication device.
FIG. 27 is a diagram showing a hardware configuration example of a communication device.
Mode for carrying out the invention
[0020]
　Hereinafter, embodiments for carrying out the present disclosure (hereinafter referred to as embodiments) will be described.
[0021]
　
　FIG. 1 is a diagram showing a wireless network configuration example of a wireless LAN system.
[0022]
　In the wireless LAN system of FIG. 1, communication devices 1-0 to communication devices 1-4 are operating on the same frequency channel. Hereinafter, when it is not necessary to distinguish between communication devices 1-0 and communication devices 1-4, they are referred to as communication device 1.
[0023]
　The wireless LAN system of FIG. 1 is composed of a first basic service set (BSS1) and a second basic service set (BSS2) connected as a wireless network. Although BSS1 and BSS2 exist as different wireless networks, they are BSSs configured using the same frequency channel, and are configured in a space where some of them overlap.
[0024]
　BSS is a group of wireless networks. For example, the group to which each communication device belongs, such as the wireless network group of Mr. A's house and the wireless network group of Mr. B's house, is restricted by a password or the like.
[0025]
　BSS1 is composed of communication device 1-0 and communication device 1-1. BSS2 is composed of communication device 1-2, communication device 1-3, and communication device 1-4.
[0026]
　Circles # 0 to circle # 4 of the alternate long and short dash line schematically indicate the radio wave reachable range of the communication devices 1-0 to 1-4 when the transmission power control is not performed, respectively. The fact that the sizes of the circles # 0 to the circles # 4 are the same indicates that the transmission power is transmitted at the maximum transmission power because the transmission power control is not performed. The white arrows indicate the data transmission direction. The same applies to FIGS. 2 and later.
[0027]
　In the example of FIG. 1, in BSS1, data is transmitted by the communication device 1-0, and in BSS2, data is transmitted by the communication device 1-2. Further, the communication device 1-1 is included in the radio wave reachable range of the communication device 1-2 of BSS2. Therefore, the communication device 1-1 of BSS1 is configured to detect the signal transmitted by the communication device 1-2 of BSS2.
[0028]
　FIG. 2 is a diagram showing an interference state of a wireless network when transmission power control is performed.
[0029]
　Circles # 0 and # 1 shown by broken lines schematically indicate the radio wave reach of the communication device 1-0 and the communication device 1-1, respectively. The fact that the circle # 0 and the circle # 1 are smaller than in the case of FIG. 1 indicates that the communication device 1-0 and the communication device 1-1 are performing the transmission power control. The circle # 2 is shown by a broken line for reference, but in FIG. 2, since the transmission power is not controlled by the communication device 1-2, the circle # 2 shown by the alternate long and short dash line is the communication device 1. It shall indicate the range of radio waves of -2.
[0030]
　In the example of FIG. 2, the communication device 1-0 and the communication device 1-1 of BSS1 perform transmission power control with each other to perform communication. In the communication method using NAV, the communication device 1-0 transmits the RTS frame and the communication device 1-1 transmits the CTS frame, so that the surrounding communication devices 1-2 receive either of them. , Communication device 1-0 and communication device 1-1 can be known.
[0031]
　However, the communication device 1-2 of BSS2 is not included in the radio wave reach range of the communication device 1-1 of BSS1. Therefore, the communication device 1-2 of BSS2 cannot grasp that the communication device 1-1 is receiving the data transmitted from the communication device 1-0 of BSS1 to the communication device 1-1. ..
[0032]
　In this case, the communication device 1-2 may determine that the transmission line is in an empty state, and may transmit data to the communication device 1-4 without performing transmission power control. ..
[0033]
　In the communication device 1-1 receiving the data transmitted by the communication device 1-0, the communication device 1-2 transmits the data to the communication device 1-4, so that the data is received in an overlapping manner. .. As a result, in the communication device 1-1, an error may occur in receiving the data transmitted by the communication device 1-0, and the data may not be correctly decoded.
[0034]
　FIG. 3 is a diagram showing a malfunction of the wireless network when transmission power control is performed.
[0035]
　The circles # 2 and # 3 shown by the broken lines schematically show the radio wave reachable range of the communication devices 1-2 and the communication devices 1-3. The fact that the circles # 2 and # 3 are smaller than in the case of FIG. 1 indicates that the communication devices 1-2 and the communication devices 1-3 are performing transmission power control.
[0036]
　In the example of FIG. 3, the communication device 1-0 and the communication device 1-1 of BSS1 perform transmission power control with each other to communicate with each other, and the communication device 1-2 and the communication device 1-3 of BSS2 transmit. Communication is performed by performing power control with each other and suppressing transmission power. The communication device 1-4 of BSS2 is not included in the radio wave reach range of the communication device 1-2.
[0037]
　In this case, the communication device 1-4 may have difficulty in detecting the signal transmitted by the communication device 1-2, and thus has a configuration that hinders the transmission / reception of data in BSS2.
[0038]
　For this reason, if the same degree of transmission power control is performed between different adjacent BSSs, communication with communication devices within the range that can originally configure the network will be hindered, so the maximum transmission power is not controlled. Communication must be carried out with transmission power.
[0039]
　FIG. 4 is a diagram showing an operation example of surrounding communication devices when a CTS frame is transmitted at the maximum transmission power on the data receiving side.
[0040]
　The circle # 0 shown by the broken line schematically shows the radio wave reach range of the communication device 1-0. The fact that the circle # 0 is smaller than that in the case of FIG. 1 indicates that the communication device 1-0 performs transmission power control to communicate data. The circle # 1 and the circle # 2 are shown by broken lines for reference, but in FIG. 4, since the transmission power is not controlled by the communication device 1-1 and the communication device 1-2, the alternate long and short dash line is used. It is assumed that the circles # 1 and # 2 indicated by the above indicate the radio wave reach of the communication device 1-1 and the communication device 1-2.
[0041]
　In the example of FIG. 4, it is assumed that the communication device 1-1 transmits the CTS frame with the maximum transmission power as the operation of performing the reception. The CTS frame transmitted by the communication device 1-1 is received by the communication device 1-2 of the surrounding BSS2, and the NAV is set in the communication device 1-2.
[0042]
　In this case, although the communication device 1-2 can receive the signal transmitted by the communication device 1-3, since the NAV is set, for example, the communication device 1- indicates a frame such as an ACK indicating the completion of reception. Cannot send to 3.
[0043]
　As described above, there is a method of transmitting a CTS frame as an operation in which the communication device 1-1 performs reception and notifies the surroundings, but in the method of transmitting a CTS frame, when transmission power control is performed, Not fully supported.
[0044]
　As described above, in the NAV setting method of the prior art, since the setting is performed both when the RTS signal is received and when the CTS signal is received, the data reception of the communication device 1 on the receiving side is not affected. The transmission of was suppressed.
[0045]
　Therefore, there is a need for a technique for notifying the surrounding communication device 1 that the communication device 1 receiving the transmitted signal by performing transmission power control by a method other than the CTS frame is using the transmission line. is there.
[0046]
　Therefore, in the present technology, the transmission side is provided with an intermittent period for interrupting the transmission, so that the data frame is transmitted. Further, on the receiving side, the data frame is received and the in-use signal (Using Signal) is transmitted during the period when the transmission is interrupted.
[0047]
　Since the communication device 1 on the receiving side that has received the data frame is configured to transmit the in-use signal using the period set intermittently, the communication device 1 existing around the receiving signal is the data. Even if the frame is not received, it is possible to know that the transmission line is in use. Here, the communication device 1 existing in the vicinity is a communication device 1 in the vicinity of the latter communication device 1 other than the communication device 1 that is transmitting a data frame and the communication device 1 that is transmitting a signal in use. Is.
[0048]
　 FIG. 5 is a diagram showing a configuration example of the wireless LAN system of the present technology.
[0049]
　Similar to FIG. 1, the wireless LAN system of FIG. 5 is composed of BSS1 and BSS2, which are network groups. Descriptions that overlap with the above description will be omitted as appropriate.
[0050]
　Circles # 1 to # 6 shown by the broken lines schematically show the radio wave reachable range when the transmission power control of the communication devices 1-1 to 1-6 is performed. Circles # 1 to # 6 indicated by the alternate long and short dash line schematically show the radio wave reachable range by the maximum transmission power when the transmission power of the communication devices 1-1 to 1-6 is not controlled.
[0051]
　In the communication device 1-2, communication is performed by controlling the transmission power. In the communication device 1-5, communication is performed by controlling the transmission power. In the communication device 1-1 to the communication device 1-6, either communication by transmission power control or communication by maximum transmission power without transmission power control is appropriately performed.
[0052]
　In the example of FIG. 5, the communication device 1-1 that receives the data frame transmitted by the communication device 1-0 of BSS1 transmits the in-use signal according to the present technology as an operation for performing the reception. .. Further, the communication device 1-2 belonging to BSS2 has a configuration capable of performing transmission within a range that does not affect the reception in the communication device 1-1.
[0053]
　That is, when the communication device 1-1 does not control the transmission power as shown by the one-point chain line circle # 1, the communication device 1-0, the communication device 1-2 to the communication device 1-4 are communication devices. It receives the in-use signal transmitted by 1-1, and grasps that it is in use to receive the signal transmitted through the transmission line by the communication device 1-1.
[0054]
　Since the communication device 1-5 does not receive the in-use signal transmitted by the communication device 1-1, the communication device 1-2 receives the data transmitted by the communication device 1-2 as indicated by the alternate long and short dash line circle # 2. However, it is also possible to transmit a signal to another communication device within a range that does not affect the reception of the communication device 1-1 that is receiving the data. Further, the communication device 1-5 transmits a signal as shown by the broken line circle # 5 so that the communication device 1-2 does not affect the reception of the response such as the ACK frame from the communication device 1-1. Occasionally, it is possible to transmit a signal to the communication device 1-5 by controlling the transmission power.
[0055]
　However, transmitting a signal from the communication device 1-2 to the communication device 1-4 without performing the transmission power control as shown by the alternate long and short dash line circle # 5 is performed on the alternate long and short dash line circle # 4. As shown, transmission of a response, such as an ACK frame, from communication device 1-4 affects the reception of signals in communication device 1-1 and communication device 1-2, and is therefore refrained from doing so.
[0056]
　
　FIG. 6 is a diagram showing a state in which a reception error occurs when the conventional transmission power control is performed.
[0057]
　From the top, the transmitting or receiving state of the transmitting side device, the receiving side device, the surrounding OBSS transmitting side device, and the surrounding OBSS receiving side device is shown. The horizontal direction represents time.
[0058]
　The transmitting side device is the transmitting side communication device 1, and corresponds to the communication device 1-0 in FIG. The receiving-side device is the receiving-side communication device 1, which corresponds to the communication device 1-1 in FIG. The OBSS transmitting side device is a transmitting side communication device 1 existing in the surrounding OBSS, and corresponds to the communication device 1-2 in FIG. The OBSS transmitting device is located in the vicinity of the receiving device existing in the BSS. The peripheral OBSS receiving side device is a receiving side communication device 1 existing in the surrounding OBSS, and corresponds to the communication device 1-3 of FIG. The OBSS is a BSS that overlaps the BSS of the transmitting side device and the receiving side device.
[0059]
　With reference to FIG. 6, when the transmitting device controls the transmission power to transmit a data frame to the receiving device, the peripheral OBSS transmitting device transmits to the surrounding OBSS receiving device. A case where the transmission of the data frame is started with the maximum transmission power without controlling the power will be described.
[0060]
　The solid line in FIG. 6 indicates the data frame to be transmitted, and the broken line indicates the data frame to be received. The height of the square indicating the data frame indicates the level of power (transmit power or receive power).
[0061]
　As shown at the top, the transmitting device transmits the preamble (P), header information (HR), MPDU (MAC layer protocol data unit) -1, MPDU-2, MPDU-3, and MPDU-4 in that order. .. MPDU-1, MPDU-2, MPDU-3, MPDU-4 Aggregated (concatenated) data frame.
[0062]
　At this time, since the transmission power of the transmission side device is suppressed, as shown in the third stage from the top, the surrounding OBSS transmission side device cannot detect the data frame transmitted by the transmission side device, and the transmission path is changed. It mistakenly determines that it is free and starts transmitting data frames.
[0063]
　That is, during reception of a data frame transmitted by performing Transmit Power Control (TPC), the surrounding OBSS transmitting side device that does not perform transmitting power control performs preamble (P), header information (HR), and Starts transmission of MPDU-1, MPDU-2, MPDU-3, and MPDU-4.
[0064]
　At this time, as shown in the second stage from the top, the receiving side device receiving the data frame transmitted by the transmitting side device has a surrounding OBSS transmitting device nearby and has a high receiving electric field strength. , Even the data frame transmitted from the surrounding OBSS transmitting device is received.
[0065]
　As a result, a reception error occurs in the receiving device. The receiving device transmits a preamble (P) and an ACK frame (BA: blockac) after the reception of the data frame is completed. The ACK frame (NG) transmitted here indicates that the reception of the data frame has failed.
[0066]
　On the other hand, as shown in the fourth row from the top, the surrounding OBSS receiving side device receiving only the data frame transmitted by the surrounding OBSS transmitting side device transmits the preamble and the ACK frame after the reception of the BSS data frame is completed. To do. The ACK frame (OK) transmitted here indicates that the data frame has been successfully received.
[0067]
　As described above, although the receiving side device receives the data frame transmitted by the transmitting side device, the receiving electric field strength of the data frame transmitted by the surrounding OBSS transmitting side device is high, so that the receiving side device A reception error has occurred.
[0068]
　In addition, the receiving device that fails to receive the data frame transmits an ACK frame indicating NG, and the surrounding OBSS receiving device that succeeds in receiving the data frame transmits an ACK frame indicating OK. If the transmission timing of the ACK frame of the receiving device and the transmission timing of the ACK frame of the surrounding OBSS receiving device overlap, the peripheral OBSS transmitting device fails to receive the ACK frame transmitted by the surrounding OBSS receiving device. There is a risk that it will end up.
[0069]
　As described above, the communication between the device in which the transmission power control is performed and the device in which the transmission power control is not performed is not performed correctly.
[0070]
　
　FIG. 7 is a diagram showing an example of communication control using the signal in use by the present technology.
[0071]
　From the top, the transmission or reception of the receiving side peripheral device, the receiving side device, the transmitting side device, the transmitting / receiving side near peripheral device, and the receiving side distant peripheral device is shown. A description that overlaps with the description of FIG. 6 will be omitted.
[0072]
　The reception-side neighborhood peripheral device is a peripheral communication device 1 existing in the vicinity of the reception-side device, and corresponds to the communication device 1-0 in FIG. The receiving side device is the receiving side communication device 1, and corresponds to the communication device 1-1 in FIG. The transmitting side device is the transmitting side communication device 1, and corresponds to the communication device 1-2 in FIG. The transmission / reception side neighborhood peripheral device is a peripheral communication device 1 that is in the vicinity of the reception side device and exists in the vicinity of the transmission side device, and corresponds to the communication device 1-3 in FIG. The receiving-side distant peripheral device is a peripheral communication device 1 that is distant from the receiving side and exists in the vicinity of the transmitting side, and corresponds to the communication device 1-4 of FIG.
[0073]
　The SR transmitting side device is a communication device that transmits a signal by using a space reuse technology (Spatial Reuse technology) that promotes spatial reuse of frequency resources, and corresponds to the communication device 1-5 of FIG. The SR receiving side device is a communication device that receives a signal transmitted by using the space reuse technology, and corresponds to the communication device 1-6 of FIG.
[0074]
　The space reuse technology is a technology that allows transmission / reception in a form of being superimposed on the preceding transmission / reception even if someone is already using the channel, if it does not affect the preceding transmission / reception.
[0075]
　As shown in the third row from the top, the transmitting device transmits a predetermined preamble (P) and header information (HR).
[0076]
　As shown in the second stage from the top, the receiving device that receives P and HR transmitted by the transmitting device intermittently transmits a using signal (US: Using Signal). The receiving device specified as the receiving device in the header information is configured to immediately return the in-use signal.
[0077]
　As shown in the uppermost stage, the receiving side peripheral device that has received only the in-use signal grasps that the communication device (receiving side device) using the transmission line exists in the surroundings for a predetermined time. be able to. In the peripheral device near the receiving side, the transmission of the data frame can be prohibited by grasping the existence of the communication device using the transmission line.
[0078]
　As shown in the fourth stage from the top, the transmitting / receiving side neighborhood peripheral device that has received both the signal transmitted by the transmitting side device and the in-use signal transmitted by the receiving side device receives both signals. Therefore, it can be understood that the receiving side device and the transmitting side device exist in the vicinity.
[0079]
　As shown in the fifth stage from the top, the receiving side distant peripheral device that receives only the signal transmitted by the transmitting side device and does not detect the in-use signal transmitted by the receiving side device transmits to its own surroundings. It is possible to grasp that there is no communication device (reception side device) that is receiving the data transmitted by the side device.
[0080]
　Therefore, even if the transmitting side device detects the signal to be transmitted, since it is located at a position away from the receiving side device, the reception of the receiving side device is less affected. It is possible to perform transmission using (SR).
[0081]
　As shown in the third row from the top, the transmitting device receives the in-use signal during the GAP period after the predetermined preamble (P) and header information (HR), and then the first data unit (MPDU). -1) is sent. GAP is the period during which transmission is interrupted. A GAP is provided when the transmission of the first data unit is completed.
[0082]
　As shown in the second stage from the top, the receiving device transmits an in-use signal during the GAP. In addition, when the next data units (MPDU-2) to (MPDU-3) are transmitted from the transmitting device following the in-use signal after MPDU-1, and the end of each data unit is reached, GAP is also performed. Are provided intermittently, and the in-use signal (US) is intermittently transmitted from the receiving device during the GAP.
[0083]
　After the last data unit (MPDU-4) is transmitted from the transmitting device following the in-use signal, the end signal (ES) is transmitted from the receiving device as shown in the second stage from the top. May be. After the end signal (ES) is transmitted, the block ACK frame may be returned from the receiving device to the transmitting device after a predetermined time has elapsed.
[0084]
　On the other hand, as shown in the sixth row from the top, the SR transmitting side device that performs transmission using the space reuse technology also provides a GAP after a predetermined preamble (P) and header information (HR), and then provides a GAP. , Send the first data unit (MPDU-1).
[0085]
　As shown in the seventh stage from the top, the SR receiving side device that receives the signal transmitted by using the space reuse technology also transmits the in-use signal during the GAP by the SR transmitting side device. The SR receiving device may also be configured to transmit an end signal (ES) or may be configured to return a block ACK frame.
[0086]
　
　FIG. 8 is a block diagram showing a configuration example of a communication device to which the present technology is applied.
[0087]
　Here, the communication device 1 will be described as a configuration capable of operating as both an access point and a communication device constituting the wireless LAN system, but parts unnecessary for each operation are omitted as necessary. May be good.
[0088]
　The communication device 1 is configured to include an Internet connection module 11, an information input module 12, a device control unit 13, an information output module 14, and a wireless communication module 15.
[0089]
　When operating as an access point, the Internet connection module 11 functions as an adapter that connects to the Internet network by wire.
[0090]
　The information input module 12 is a unit that receives when an action requested by the user is input, and determines the input based on the input from the keyboard or the voice of the user.
[0091]
　The device control unit 13 stores a CPU (Central Processing Unit) that centrally manages the control of the operation of the communication device 1 and executes arithmetic processing, and functions corresponding to the OS and applications.
[0092]
　The information output module 14 is a unit that outputs information to, for example, a user, and outputs desired data to the user by displaying the information on, for example, a display.
[0093]
　The wireless communication module 15 operates as a communication module for actually performing a wireless communication operation.
[0094]
　
　FIG. 9 is a block diagram showing an example of functional configuration of the wireless communication module of FIG.
[0095]
　The wireless communication module 15 is configured to include an interface 101, a transmission buffer 102, a network management unit 103, a transmission frame construction unit 104, a wireless communication control unit 105, a header information generation unit 106, and a signal generation unit 107 in use. ..
[0096]
　The wireless communication module 15 is configured to include a transmission timing control unit 108, a transmission power control unit 109, a wireless transmission processing unit 110, an antenna control unit 111, an antenna 111-1A and an antenna 111-1B, and a wireless reception processing unit 112. To.
[0097]
　Further, the wireless communication module 15 is configured to include a detection threshold control unit 113, a reception timing control unit 114, a signal detection unit 115 in use, a header information analysis unit 116, a reception data construction unit 117, and a reception buffer 118. ..
[0098]
　Wireless communication control unit 105, header information generation unit 106, in-use signal generation unit 107, transmission timing control unit 108, reception timing control unit 114, in-use signal detection unit 115, header information analysis, surrounded by a broken line in the center. The unit 116 is a unit that controls communication.
[0099]
　The transmission power control unit 109, the wireless transmission processing unit 110, the antenna control unit 111, the antenna 111-1A, the antenna 111-1B, the wireless reception processing unit 112, and the detection threshold control unit 113 surrounded by the broken line in the lower row are actually communicating. This is the part related to processing and power control.
[0100]
　The interface 101 is an interface unit with the device control unit 13 of FIG. The interface 101 supplies the data supplied by the device control unit 13 to the transmission buffer 102, and supplies the data stored in the reception buffer 118 to the device control unit 13. The interface 101 supplies the information supplied by the device control unit 13 to the network management unit 103, and supplies the information of the surrounding wireless network managed by the network management unit 103 to the device control unit 13.
[0101]
　The transmission buffer 102 stores MPDU data for wireless transmission supplied from the device control unit 13. The transmission buffer 102 supplies the stored data to the transmission frame construction unit 104 at a predetermined timing.
[0102]
　The network management unit 103 communicates with the surrounding communication device 1 in the OBSS, which is a surrounding wireless network that overlaps with its own BSS, based on the information supplied by the wireless communication control unit 105 and the interface 101. Manage attribute information such as device addresses. The network management unit 103 supplies the attribute information of the BSS to be managed to the transmission frame construction unit 104, the wireless communication control unit 105, the interface 101, and the reception data construction unit 117, if necessary.
[0103]
　The transmission frame construction unit 104 uses the data from the transmission buffer 102 to generate a wireless communication frame for wireless communication in a predetermined aggregation unit, and the generated wireless communication frame is used by the header information generation unit 106 and wireless transmission processing. It is supplied to the unit 110.
[0104]
　The wireless communication control unit 105 executes access communication control on the wireless transmission path according to a predetermined communication protocol based on the information supplied by the network management unit 103, the in-use signal detection unit 115, and the header information analysis unit 116.
[0105]
　The wireless communication control unit 105 controls the transmission power control unit 109, sets the transmission power, controls the detection threshold value control unit 113, acquires the received power, and controls the power related to communication. The wireless communication control unit 105 supplies the information obtained as a result of the access communication control to the header information generation unit 106, the in-use signal generation unit 107, and the network management unit 103.
[0106]
　The header information generation unit 106 generates predetermined preamble and header information to be added to the head portion of the data frame generated by the transmission frame construction unit 104 under the control of the wireless communication control unit 105. The header information generation unit 106 supplies the generated predetermined preamble and header information to the in-use signal generation unit 107. The header information generation unit 106 adds the generated predetermined preamble and header information to the data frame from the transmission frame construction unit 104, and supplies the generated predetermined preamble and header information to the wireless transmission processing unit 110.
[0107]
　The in-use signal generation unit 107 is receiving a data frame and is using the transmission line based on the information supplied by the wireless communication control unit 105, the header information generation unit 106, and the detection threshold value control unit 113. Generates an in-use signal that indicates to the surroundings. The in-use signal generation unit 107 supplies the generated in-use signal to the transmission timing control unit 108 and the wireless transmission processing unit 110.
[0108]
　The transmission timing control unit 108 controls the timing at which the wireless transmission processing unit 110 transmits a data frame or a signal in use on the transmission path based on the information supplied by the reception timing control unit 114 and the transmission power control unit 109.
[0109]
　Under the control of the wireless communication control unit 105 and the transmission timing control unit 108, the transmission power control unit 109 needs the transmission power of the transmission frame transmitted by the wireless transmission processing unit 110 toward the transmission destination communication device. Control accordingly.
[0110]
　The wireless transmission processing unit 110 includes a data frame to which the header information generated by the header information generation unit 106 is added, a data frame generated by the transmission frame construction unit 104, an in-use signal generated by the in-use signal generation unit 107, and a transmission frame. Is converted into a predetermined baseband signal to perform modulation processing and signal processing. The wireless transmission processing unit 110 supplies the baseband signal after signal processing to the antenna control unit 111 so as to transmit with the transmission power controlled by the transmission power control unit 109 at the timing controlled by the transmission timing control unit 108. To do.
[0111]
　The antenna control unit 111 controls the antenna 111-1A and the antenna 111-1B composed of a plurality of elements, and transmits or receives a signal from the transmission line. At least one of the antenna 111-1A and the antenna 111-1B transmits a signal from the wireless transmission processing unit 110 to the transmission line. At least one of the antenna 111-1A and the antenna 111-1B supplies the signal received from the transmission line to the wireless reception processing unit 112.
[0112]
　The wireless reception processing unit 112 receives the data frame wirelessly transmitted in a predetermined format via the antenna 111-A or the antenna 111-1B. The wireless reception processing unit 112 supplies the received data frame to the detection threshold control unit 113, the reception timing control unit 114, the header information analysis unit 116, and the reception data construction unit 117.
[0113]
　The detection threshold control unit 113 sets a threshold value for detecting the preamble and the mid amble included in the received signal, and detects a signal (data frame) having a reception power larger than the set threshold value. The detected received power information is supplied to the in-use signal generation unit 107, the reception timing control unit 114, and the wireless reception processing unit 112.
[0114]
　The reception timing control unit 114 wirelessly based on the information of the received power from the detection threshold control unit 113, the parameters of the in-use signal detected by the in-use signal detection unit 115, the header information analyzed by the header information analysis unit 116, and the like. The reception processing unit 112 controls the timing of receiving the data frame and the inserted signal in use. The reception timing control unit 114 supplies information on the reception timing of the data frame and the inserted signal in use to the transmission timing control unit 108.
[0115]
　The in-use signal detection unit 115 grasps the use of the transmission line by detecting the in-use signal from the header information analyzed by the header information analysis unit 116, and analyzes and analyzes the parameters described in the in-use signal. The generated parameters are supplied to the reception timing control unit 114 and the wireless communication control unit 105.
[0116]
　The header information analysis unit 116 extracts the header information and analyzes the content of the header information by detecting the preamble added to the beginning of the frame. The details will be described later, but since the signal in use is also compatible with the existing preamble, it is extracted as header information. The header information analysis unit 116 supplies the header information, the analysis result of the header information, and the like to the reception timing control unit 114, the in-use signal detection unit 115, the reception data construction unit 117, and the wireless communication control unit 105.
[0117]
　The reception data construction unit 117 receives the aggregated reception received by the wireless reception processing unit 112 based on the network management information managed by the network management unit 103 and the analysis result of the header information analyzed by the header information analysis unit 116. A frame is generated as received data in a predetermined unit. The reception data construction unit 117 stores the reception data in the reception buffer 118.
[0118]
　The reception buffer 118 stores the data of the MPDU generated by the reception data construction unit 117. The reception buffer 118 is read out at a predetermined timing and supplied to the device control unit 13 via the interface 101.
[0119]
　In the example of FIG. 9, since the in-use signal is compatible with the existing preamble, the configuration in which the in-use signal detection unit 115 detects the in-use signal from the header information from the header information analysis unit 116 will be described. However, the in-use signal detection unit 115 may be configured to directly detect the in-use signal from the received frame.
[0120]
　
　FIG. 10 is a diagram showing a configuration example of a conventional aggregated MPDU (A-MPDU) frame.
[0121]
　An A-MPDU frame consists of a predetermined preamble, a PLCP header (Header), and a MAC layer protocol data unit (MPDU).
[0122]
　The preamble consists of the Legacy Short Training Field (L-STF), the Legacy Long Training Field (L-LTF), and the Legacy Signal (L-SIG).
[0123]
　L-STF indicates the beginning of the frame. L-LTF provides information for correcting timing and frequency errors. L-SIG indicates the modulation method / coding rate setting and signal duration of the data part that follows.
[0124]
　The PLCP header is composed of a high-throughput signal (HT-SIG), a high-throughput short training field (HT-STF), a high-throughput long training field (HT-STF), and the like.
[0125]
　The HT-SIG and HT-STF are recognized as part of the preamble and generally contain a variety of information needed for the newly expanded functionality. HT-STF is used to perform channel estimation.
[0126]
　Following these preambles, an MPDU is configured as a data payload. A plurality of MPDU subframes can be aggregated into an MPDU to form one burst. FIG. 10 shows an example of aggregating four subframes from MPDU-1 to MPDU-4.
[0127]
　In the MPDU subframe, a frame check sequence (FCS) is added to the actual data part (MPDU) of the delimiter (Delimiter) in which the length information and the like are described, and padding processing is performed as necessary. The detailed configuration of the MPDU subframe will be described later in FIG.
[0128]
　FIG. 11 is a diagram showing an example of an A-MPDU frame configuration used in the present technology.
[0129]
　FIG. 11 shows a configuration example of the MAC layer protocol data unit (MPDU) of FIG.
[0130]
　The frame of FIG. 11 has a GAP section indicated by G inserted at the boundary of the MPDU, and the communication device 1 on the receiving side can return the in-use signal at the GAP timing.
[0131]
　That is, the GAP is configured as a time interval during which the in-use signal can be returned. The GAP need not be configured to include a predetermined interframe space time interval. For example, the GAP may be composed of the information length of the signal frame in use at the switching time of the transmission / reception operation.
[0132]
　In addition, the MPDU-0 header is set at the beginning of the A-MPDU. The MPDU-0 header is composed of Type indicating the frame format, information capable of identifying the address information of the target communication device 1, length information indicating the total length, various parameter information, CRC for error detection, and the like. ..
[0133]
　When the communication device 1 on the receiving side that has received the frame describes its own address information as the address information of the target communication device 1, it prepares to transmit the signal in use, and the GAP timing has arrived. If this happens, it is desirable to be prepared for immediate transmission.
[0134]
　In the MPDU, following the GAP, subframes of each MPDU shown in FIG. 10 are configured. The MPDU of FIG. 11 is composed of four subframes from MPDU-1 to MPDU-4.
[0135]
　In addition, each MPDU shown in FIG. 11 may be fragmented to a predetermined length and configured as a MAC layer service data unit (MSDU).
[0136]
　FIG. 12 is a diagram showing an example of a frame configuration of a using signal.
[0137]
　The Using Signal frame of FIG. 12 is composed of L-STF, L-LTF, L-SIG, and the Using Signal parameter, which is a feature of the present technology.
[0138]
　That is, L-STF, L-LTF, and L-SIG have parameter arrangements compatible with the conventional preamble, and the existence of the Using Signal frame can be grasped even in the existing communication device.
[0139]
　FIG. 13 is a diagram showing an example of a frame configuration of End Signal.
[0140]
　The End Signal frame of FIG. 13 is composed of L-STF, L-LTF, and L-SIG.
[0141]
　In addition, in the End Signal frame, in order to notify that the A-MPDU frame has ended, all the parameters described in the L-SIG may be configured to describe 0.
[0142]
　FIG. 14 is a diagram showing the arrangement of parameters in the L-SIG and Using Signal parameters.
[0143]
　L-SIG is a RATE field (4 bits), R bit (1 bit), LENGTH field (12 bits), Parity P bit (1 bit), Tail bit field (6 bits) to maintain compatibility with existing products. ) Consists of. The RATE field indicates the modulation method / coding rate of the data part. The R bit indicates that it is the L-SIG of this technology. The LENGTH field indicates the remaining information length of the data portion. For example, in the LENGTH field, the reception duration calculated based on the parameter describing the duration of the data frame added to the data frame is described.
[0144]
　The Using Signal parameter is composed of, for example, the length of 2OFDM symbols, but depending on the amount of information, it may be configured with the length of 1OFDM symbol or the length of 3OFDM symbols or more. Good.
[0145]
　Using Signal parameters are Type (2 bits), RSI (4 bits), BSS Color information (6 bits), AID12 information (12 bits), ACK bitmap information (Sequence) (12 bits), TPC information (2 bits). , CRC (4 bits), Tail bit field (6 bits).
[0146]
　Type indicates the frame format. The RSI is information on the received electric field strength of the data frame obtained when the data frame is received. BSS Color is information that identifies BSS (network). AID12 is an association identifier that can identify a communication device, and TPC information is transmission power control parameter information when transmitting a signal in use. The TPC information may be information added to the header information of the data frame. The Using Signal parameter may also contain information that identifies the communication device that sent the data frame.
[0147]
　In recent years, when detecting a signal from OBSS, it is not possible to determine the use of a transmission line unless the transmitted signal can be received in order to apply the space reuse technology that is being standardized.
[0148]
　That is, the communication device 1 that receives the signal in OBSS does not transmit the signal in which the BSS color information is described, and the communication device 1 on the receiving side cannot transmit the signal during reception, so that it interferes with reception. Level signals could sometimes be transmitted by spatial reuse technology.
[0149]
　On the other hand, since the BSS Color information is entered in the Using Signal parameter, the surrounding communication device 1 that received the in-use signal can grasp which BSS the communication device 1 that is receiving data belongs to. can do.
[0150]
　In addition, there was a need for a technology to notify the overlapping BSS (OBSS) that transmission power control is being performed within its own BSS.
[0151]
　Spatial reuse technology is defined by describing parameters such as BSS Color information in the signal of the communication device 1 on the transmitting side. However, after grasping the level at which reception is required in the communication device 1 on the receiving side, It was necessary to apply the space reuse technology within the range that does not affect the reception.
[0152]
　On the other hand, since the TPC information is described in the Using Signal parameter, the communication device 1 that has received the signal in use grasps the level at which reception is required, and within a range that does not affect the reception. , Space reuse technology can be applied.
[0153]
　It should be noted that these parameters are examples, and may be adjusted as necessary. Further, in FIG. 14, although the parameters are tentatively arranged, the arrangement is not limited to this order, and the arrangement order may be appropriately changed as necessary.
[0154]
　
　Next, the GAP time will be described while explaining the OFDM signals in order.
[0155]
　FIG. 15 is a diagram showing an example of a subcarrier configuration of an OFDM signal.
[0156]
　At a bandwidth of 20 MHz, the 1OFDM symbol consists of 52 subcarriers, 4 of which are pilot subcarriers indicated by P in the figure. That is, 48 ​​1OFDM symbols are used as the data subcarriers indicated by D in the figure.
[0157]
　In FIG. 15, the center frequency 0 is set as a DC null carrier, and +/- 26 subcarriers (52 in total) are composed. Of these, subcarriers -21, -7, +7,- Four of 21 are used as pilot subcarriers.
[0158]
　FIG. 16 is a diagram showing the relationship between the modulation method and the coding rate.
[0159]
　In FIG. 16, in the case of modulation method BPSK, coding rate R = 1/2, and coding for each subcarrier, 48-bit information can be encoded with 10 FDM symbols, 24-bit information can be transmitted, and the data rate. Is shown to be 6Mb / s (20MHz channel space), 3Mb / s (10MHz channel space), 1.5Mb / s (5MHz channel space). In the case of modulation method BPSK, coding rate R = 3/4, coding for each subcarrier, 48-bit information can be encoded with 10 FDM symbols, 36-bit information can be transmitted, and the data rate is 9 Mb / s. It has been shown to be (20MHz channel space), 4.5Mb / s (10MHz channel space), and 2.25Mb / s (5MHz channel space).
[0160]
　In the case of modulation method QPSK, coding rate R = 1/2, coding every 2 subcarriers, 96-bit information can be encoded with 10 FDM symbols, 48-bit information can be transmitted, and the data rate is 12 Mb / s. It has been shown to be (20MHz channel space), 6Mb / s (10MHz channel space), and 3Mb / s (5MHz channel space). In the case of modulation method QPSK, coding rate R = 3/4, coding every 2 subcarriers, 96-bit information can be encoded with 10 FDM symbols, 72-bit information can be transmitted, and the data rate is 18 Mb / s. It has been shown to be (20MHz channel space), 9Mb / s (10MHz channel space), and 4.5Mb / s (5MHz channel space).
[0161]
　In the case of modulation method 16-QAM, coding rate R = 1/2, coding every 4 subcarriers, 192 bits of information can be encoded with 10 FDM symbols, 96 bits of information can be transmitted, and the data rate is 24 Mb. It has been shown to be / s (20MHz channel space), 12Mb / s (10MHz channel space), and 6Mb / s (5MHz channel space). In the case of modulation method 16-QAM, coding rate R = 3/4, coding every 4 subcarriers, 192 bits of information can be encoded with 10 FDM symbols, 144 bits of information can be transmitted, and the data rate is 36 Mb. It has been shown to be / s (20MHz channel space), 18Mb / s (10MHz channel space), and 9Mb / s (5MHz channel space).
[0162]
　In the case of modulation method 64-QAM, coding rate R = 2/3, coding every 6 subcarriers, 288-bit information can be encoded with 10FDM symbols, 192-bit information can be transmitted, and the data rate is 48Mb. It has been shown to be / s (20MHz channel space), 24Mb / s (10MHz channel space), and 12Mb / s (5MHz channel space). In the case of modulation method 64-QAM, coding rate R = 3/4, coding every 6 subcarriers, 288-bit information can be encoded with 10 FDM symbols, 216-bit information can be transmitted, and the data rate is 54 Mb. It has been shown to be / s (20MHz channel space), 27Mb / s (10MHz channel space), and 13.5Mb / s (5MHz channel space).
[0163]
　In a wireless LAN system, the amount of information that can be transmitted per 10 FDM symbols varies depending on the modulation method (Modulation) and coding rate (Coding Rate) used.
[0164]
　Representative from the example of FIG. 16, for example, in the case of the modulation method BPSK and the coding rate R = 1/2, 24-bit information can be transmitted with a 10FDM symbol, the modulation method 64-QAM, and the coding rate R = 3 /. In the case of 4, it can be seen that 216-bit information can be transmitted with the 10FDM symbol.
[0165]
　FIG. 17 is a diagram showing a configuration example of the preamble. FIG. 17 shows a detailed configuration example of the preamble portion shown in FIG.
[0166]
　As shown in FIG. 17, the preamble is composed of predetermined parameter values ​​in a format determined for synchronizing signals as a training sequence added to the beginning of a frame.
[0167]
　The preamble in FIG. 17 is twice as long as the data symbol (8 + 8 = 16 μs) so that the frame can be detected, and the short synchronization signal (t1 to t10) is repeated 10 times for STF and channel estimation. It consists of two parts of the long LTF used. The STF and LTF are separated by a guard interval (GI).
[0168]
　In STF, signal detection, AGC, and diversity selection are performed at t1 to t7, and coarse frequency offset evaluation and timing synchronization are performed at t8 to t10. In LTF, channel and fine frequency offset evaluation are performed.
[0169]
　Following the preamble, the Legacy SIGNAL (L-SIG) field part in which the PHY parameters are described is configured, followed by the data part. The L-SIG and the data part are also separated by guard intervals. The L-SIG field is always placed in the first OFDM symbol so that it can be transmitted while maintaining compatibility with the existing frame structure.
[0170]
　FIG. 18 is a diagram showing a configuration example of the L-SIG field. FIG. 18 shows a configuration example of the L-SIG shown in FIG. 14, and since the configurations are the same, the description thereof will be omitted.
[0171]
　That is, the L-SIG field is composed of a RATE field that specifies the modulation method and code rate of the frame and a LENGTH field that indicates the frame length, and since the Tail bit is arranged, it is possible to terminate the decoding. ..
[0172]
　Here, one OFDM symbol has a unit of time (4 μs) that can be recognized as data at a predetermined time. As a result, it takes a certain amount of time to send the actual data by using multiple OFDM symbols.
[0173]
　Actually, the SIGNAL field is placed in front of the data frame, the 16-bit Service is placed in the first data frame part and the Tail bit is placed in the data part at the end, and the part less than the OFDM symbol is Padding. Be given.
[0174]
　FIG. 19 is a diagram showing a configuration example of A-MPDU. For OFDM signals, a technique is used in which a plurality of MPDUs are connected to form one aggregated MPDU (A-MPDU) configuration.
[0175]
　FIG. 19 shows a configuration in which the A-MPDU of the subframe 1 to the A-MPDU of the subframe n are aggregated.
[0176]
　In this way, transmission efficiency can be improved by sending a plurality of A-MPDU subframes together. However, if it is simply put together in succession, it will not be possible to know where the break is, so a delimiter is added to the beginning of the MPDU so that the break in the MPDU can be known in advance.
[0177]
　FIG. 20 is a diagram showing a detailed configuration example of one MPDU among the A-MPDUs.
[0178]
　The MPDU consists of the MPDU delimiter (4 Octets), the MPDU (Octets is variable), and the Pad (0-3 Octets). As shown in FIG. 20, the MPDU is configured by adding a delimiter to the beginning of each MPDU.
[0179]
　FIG. 21 is a diagram showing a configuration example of the MPDU delimiter.
[0180]
　The MPDU delimiter consists of a 4-bit Reserved, a 12-bit MPDU length, a b-bit CRC, and an 8-bit Delimiter Signature.
[0181]
　Here, as a feature of the present technology, padding is performed for each MPDU with respect to the length of the MPDU described in the MPDU delimiter.
[0182]
　FIG. 22 is a diagram showing an example of internal configuration of the MPDU.
[0183]
　The inside of the MPDU is composed of a MAC header, a frame body, and an FCS, and the source and destination address information is described in the MAC header part.
[0184]
　The MAC headers in FIG. 22 are 2 Octets Frame Control, 2 Octets Duration ID, 6 Octets Address1, 6 Octets Address2, 6 Octets Address3, 2 Octets Sequence Control, 6 Octets Address4, and 2 Octets QoS Control. , 4 Octets HT control, 0-7951 Octets Frame body, and 4 Octets FCS.
[0185]
　The error detection of the MAC header is configured so that the correctness cannot be determined unless the FCS at the end is decoded, and it takes time to identify which device should return the signal in use.
[0186]
　Therefore, it is necessary to specify the Target Address and specify it in the MPDU Header without waiting for the FCS at the end. Therefore, in the present technology, as shown in FIG. 11, the MPDU Header is configured independently. ..
[0187]
　FIG. 23 is a diagram showing a configuration example of padding.
[0188]
　In this technology, since GAP is inserted in MPDU units, padding is required until the number is divisible by the number of subcarriers of the OFDM symbol (24-bit or 216-bit unit) for each MPDU.
[0189]
　That is, if the data length of the MPDU to be transmitted is not divisible by 1OFDM Symbol, padding is added. Specifically, in the case of BPSK and R = 1/2, padding is performed on the part that is not divisible by 24 bits.
[0190]
　In the case of the example of FIG. 23, in order from the top, MPDU-1 is padded with a data length of D15. MPDU-2 is padded with a data length of D10. MPDU-3 has a data length of D13 and is not padded. The data length of MPDU-4 is padded with D12.
[0191]
　In the present technology in which padding and the like are configured as described above, a frame is constructed by inserting an MPDU header and a GAP as described above in FIG.
[0192]
　The GAP is set with an OFDM symbol that is the time length of a predetermined signal in use. That is, if the predetermined preamble (8 μsec × 2), L-SIG (4 μsec), and the Using Signal parameter (8 μsec) of the present technology are set, the GAP is configured as a time of 28 μsec. However, the GAP time may be adjusted as appropriate depending on the configuration of the signal in use.
[0193]
　
　Next, a processing example of the communication device 1 on the transmitting side will be described with reference to the flowchart of FIG. 24. The transmitting side communication device 1 corresponds to the transmitting side device of FIG. 7.
[0194]
　In step S101, the transmission buffer 102 and the network management unit 103 acquire transmission data from the application (device control unit 13) to be transmitted via the interface 101. The network management unit 103 manages attribute information such as the address of the communication device included in the BSS, which is a group of the surrounding wireless networks that overlaps with its own BSS with the surrounding communication device.
[0195]
　In step S102, the network management unit 103 acquires the attribute information of the communication device 1 on the receiving side based on the transmission data acquired via the interface 101.
[0196]
　In step S103, the network management unit 103 determines whether or not the communication method of the communication device 1 on the receiving side corresponds to the signal in use. If it is determined in step S103 that the signal in use is not supported, the process proceeds to step S104.
[0197]
　In step S104, the transmission frame construction unit 104 generates a data frame by the existing communication method under the control of the network management unit 103.
[0198]
　If it is determined in step S103 that the signal is being used, the process proceeds to step S105. In step S105, the transmission frame construction unit 104 generates a data frame corresponding to the signal in use under the control of the network management unit 103. The data frame to be generated may be a configuration in which a plurality of MPDUs are put together so as to have a predetermined aggregated MPDU configuration.
[0199]
　The generated data frame is supplied to the header information generation unit 106 and the wireless transmission processing unit 110. The header information generation unit 106 generates a predetermined preamble and header information to be added to the head portion of the frame supplied from the transmission frame construction unit 104 based on the information supplied by the wireless communication control unit 105. In the header information, information for identifying the communication device 1 of the transmission destination, information regarding the transmission power of the data frame, and the like are described.
[0200]
　The wireless reception processing unit 112 receives the transmission line signal via the antenna 111-1B, and when the signal is detected by the detection threshold control unit 113, it is wirelessly transmitted in a predetermined format from the surrounding communication device 1. Determine if a data frame is included. When the wireless reception processing unit 112 determines that a data frame wirelessly transmitted in a predetermined format from the surrounding communication device 1 is included, the received data frame is supplied to the header information analysis unit 116.
[0201]
　The header information analysis unit 116 detects the preamble from the received data frame, analyzes the header information, and supplies the analysis result to the wireless communication control unit 105. When the header information is included, the header information analysis unit 116 supplies the header information to the in-use signal detection unit 115. The in-use signal detection unit 115 detects whether or not there is an in-use signal in the header information.
[0202]
　Here, since the in-use signal is compatible with the existing preamble, the in-use signal detection unit 115 is configured to detect the in-use signal from the header information from the header information analysis unit 116. The signal detection unit 115 may be configured to directly detect the signal in use from the received data frame.
[0203]
　When the in-use signal is detected, the in-use signal detection unit 115 supplies the in-use signal information to the wireless communication control unit 105, and another communication device receiving the frame transmitted on the transmission path causes the in-use signal detection unit 115. Know that it exists. Such an access procedure is performed. The access procedure is an example and is not limited to this.
[0204]
　In step S106, the wireless communication control unit 105 uses the data frame on the transmission line based on the analysis result analyzed by the header information analysis unit 116 and the detection result detected by the in-use signal detection unit 115 after the predetermined access procedure. Is determined whether or not it is possible to transmit. In step S106, it waits until it is determined that the data frame can be transmitted on the transmission line.
[0205]
　If the in-use signal is not detected, and if it is determined in step S106 that the transmission line is empty, that is, it is possible to transmit a data frame on the transmission line, the process proceeds to step S107. In step S107, the wireless communication control unit 105 controls the header information generation unit 106 to transmit a data frame.
[0206]
　The header information generation unit 106 adds the generated header information to the data frame generated by the transmission frame construction unit 104, and supplies the generated header information to the wireless transmission processing unit 110. The wireless transmission processing unit 110 converts the data frame to which the header information generated by the header information generation unit 106 is added into a predetermined baseband signal, performs modulation processing and signal processing, and performs the modulation processing and signal processing, and the baseband after the signal processing. The signal is transmitted via the antenna 111-1A.
[0207]
　At this time, the frame may be transmitted with the minimum transmission power that can be received by the communication device 1 on the receiving side under the control of the transmission power control unit 109. Further, the frame is transmitted with a transmission power value that does not affect the OBSS communication calculated based on the information of the received electric field strength when the in-use signal is received and the received electric field strength described in the in-use signal. It may be.
[0208]
　In step S108, the wireless communication control unit 105 determines whether or not the position is where the in-use signal is arranged, and if it is determined that the position is not where the in-use signal is arranged, the process returns to step S107. Subsequent processing is repeated.
[0209]
　If it is determined in step S108 that the signal is in use, the process proceeds to step S109. In step S109, the transmission timing control unit 108 inserts the GAP under the control of the wireless communication control unit 105.
[0210]
　The GAP insertion method is not limited to controlling the transmission timing, but a method such as inserting empty data in the GAP part when creating a data frame so that no signal is output only in the GAP part can be considered. ..
[0211]
　In step S110, the wireless communication control unit 105 determines whether or not the in-use signal has been detected based on the detection result from the in-use signal detection unit 115 after the predetermined access procedure described above. If it is determined in step S110 that the in-use signal has been detected, the process proceeds to step S111.
[0212]
　In step S111, the wireless communication control unit 105 acquires the parameters described in the in-use signal detected by the in-use signal detection unit 115. At this time, the wireless communication control unit 105 may monitor the condition of the transmission line, if necessary.
[0213]
　After that, the process proceeds to step S114.
[0214]
　On the other hand, if it is determined in step S110 that the in-use signal has not been detected, the process proceeds to step S112. In step S112, the wireless communication control unit 105 performs a predetermined access procedure and determines whether or not the in-use signal is continuously undetected.
[0215]
　If it is determined in step S112 that the in-use signal has not been continuously detected, the process proceeds to step S113. In step S113, the wireless communication control unit 105 determines whether or not to perform retransmission, and if it is determined that retransmission is not performed, the process of the communication device 1 on the transmitting side ends.
[0216]
　If it is determined in step S113 that the retransmission is to be performed, the process returns to step S106, and the subsequent processes are repeated. If it is determined in step S112 that the in-use signal is not continuously undetected, the process proceeds to step S114.
[0217]
　In step S114, the wireless communication control unit 105 determines whether or not it is the end of the data frame. If it is determined in step S114 that it is not the end of the data frame, the process returns to step S107, and the subsequent processes are repeated.
[0218]
　If it is determined in step S114 that it is the end of the data frame, the processing of the communication device 1 on the transmitting side is terminated. After that, as in the conventional case, the communication device 1 on the transmitting side may be configured to confirm whether or not the data frame has been received by exchanging the ACK frame.
[0219]
　If the communication method does not correspond to the in-use signal, the processing related to the in-use signal in steps S108 to S111 is skipped.
[0220]
　
　Next, a processing example of the communication device 1 on the receiving side will be described with reference to the flowchart of FIG. The communication device 1 on the receiving side corresponds to the receiving device in FIG. 7.
[0221]
　The access procedure described above is performed in FIG. 24, and in step S151, the wireless communication control unit 105 determines whether or not the header information analysis unit 116 has detected the preamble, and waits until it is determined that the preamble has been detected. If it is determined in step S151 that the preamble has been detected, the process proceeds to step S152.
[0222]
　In step S152, the wireless communication control unit 105 acquires the PLCP header information analyzed by the header information analysis unit 116, and if the data frame corresponds to the in-use signal, the data frame corresponds to the in-use signal. Remember that.
[0223]
　In step S153, the wireless communication control unit 105 acquires the received electric field strength when the in-use signal is received from the detection threshold value control unit 113.
[0224]
　In step S154, the received data construction unit 117 receives the data payload (or MPDU-0 header) and decodes it until the end of the MPDU.
[0225]
　In step S155, the received data construction unit 117 determines whether or not the data can be decoded without error until the end of the MPDU. If it is determined in step S155 that the decoding could be performed without error, the process proceeds to step S156. In step S156, the reception data construction unit 117 acquires the data payload and stores it in the reception buffer 118.
[0226]
　In step S157, the received data construction unit 117 generates ACK information of the received data frame. The generated ACK information may be included in the in-use signal or may be transmitted as a block ACK frame at the end of transmission.
[0227]
　If it is determined in step S155 that the decoding could not be performed without error until the end of the MPDU, the processes of steps S156 and S157 are skipped, and the process proceeds to step S158.
[0228]
　In step S158, the transmission timing control unit 108 determines whether or not it is the position of the signal in use. In step S159, the transmission timing control unit 108 acquires the in-use signal generated by the in-use signal generation unit 107. In step S160, the wireless transmission processing unit 110 transmits the in-use signal supplied by the transmission timing control unit 108.
[0229]
　Here, the transmission power control unit 109 transmits a normal data frame with the minimum power that can be received by the communication device 1 on the receiving side. On the other hand, the transmission power control unit 109 controls the in-use signal so that it is transmitted with a transmission power larger than that of a normal data frame.
[0230]
　In step S161, the wireless communication control unit 105 determines whether or not the end of the data frame has arrived. For example, when the aggregated MPDU continues, it is determined in step S161 that the end of the data frame has not arrived, so the process returns to step S154, and the subsequent processes are repeated. If it is determined in step S161 that the end of the data frame has arrived, the processing of the communication device 1 on the receiving side is terminated.
[0231]
　
　Next, a processing example of the surrounding communication device 1 will be described with reference to the flowchart of FIG. The peripheral communication device 1 corresponds to at least one of the receiving side near peripheral device, the transmitting / receiving side near peripheral device, the receiving side far peripheral device, the SR transmitting side device, and the SR receiving side device in FIG. 7.
[0232]
　The above-mentioned access procedure is performed, and in step S201, the wireless communication control unit 105 waits until it is determined that the in-use signal detection unit 115 has detected the in-use signal. If it is determined in step S201 that the in-use signal has been detected, the process proceeds to step S202.
[0233]
　In step S202, the wireless communication control unit 105 acquires the parameters described in the in-use signal detected by the in-use signal detection unit 115. In step S203, the wireless communication control unit 105 determines whether or not the detected in-use signal is an OBSS signal by referring to the acquired parameters such as BSS Color information.
[0234]
　If it is determined in step S203 that it is not an OBSS signal, it is a BSS signal, so the processing of the surrounding communication device 1 is terminated.
[0235]
　If it is determined in step S203 that the signal is an OBSS signal, the process proceeds to step S204. In step S204, the wireless communication control unit 105 determines whether or not the detected in-use signal corresponds to space reuse with reference to the acquired parameter.
[0236]
　If it is determined in step S204 that the space is reused, the process proceeds to step S205. In step S205, the wireless communication control unit 105 determines the transmission power value that does not affect the OBSS communication based on the information of the received electric field strength when the in-use signal is received and the received electric field strength described in the in-use signal. calculate.
[0237]
　In step S206, the wireless communication control unit 105 refers to the information managed by the network management unit 103 and determines whether or not there is a schedule for data frame transmission within its own BSS. If it is determined in step S206 that there is no schedule for data frame transmission in the BSS, the processing of the surrounding communication device 1 is terminated.
[0238]
　If it is determined in step S206 that the data frame is scheduled to be transmitted in the BSS, the process proceeds to step S207.
[0239]
　In step S207, the wireless communication control unit 105 sets a backoff time for waiting for transmission. In step S208, the wireless communication control unit 105 determines that the set backoff time has expired, and waits until it determines that the set backoff time has expired. If it is determined in step S208 that the set backoff time has expired, the process proceeds to step S209.
[0240]
　In step S209, the transmission power control unit 109 sets the transmission power calculated by the wireless communication control unit 105.
[0241]
　In step S210, the wireless transmission processing unit 110 transmits a data frame (or a data frame generated by the transmission frame construction unit 104) to which the header information generated by the header information generation unit 106 is added.
[0242]
　In addition, in FIGS. 24 to 26, the processing is described separately as the communication device 1 on the transmitting side, the communication device 1 on the receiving side, and the surrounding communication device 1, but any of the processes can be performed by the communication device 1. Therefore, each step used in the three processes may be used in any process, if necessary. The order of the steps may also be changed.
[0243]
　As described above, in the present technology, since the in-use signal is intermittently transmitted from the data frame receiving side, it is possible to notify the device in the interference range that affects the reception.
[0244]
　For example, in the aggregated A-MPDU frame, by securing the area of ​​the signal in use after the MPDU subframe, the existence of the device receiving the data frame can be notified to the surrounding devices in a short cycle.
[0245]
　Conventionally, in the method of notifying the use of a transmission line using a busy tone, a channel for transmitting a busy tone signal or the like is required, and a communication block for transmitting and receiving a busy tone signal is required.
[0246]
　On the other hand, according to the present technology, by using the signal in use, it is possible to process the tone signal as it is without using the transmission / reception circuit or the filter.
[0247]
　When setting NAV by exchanging the conventional RTS / CTS frame, the surrounding communication device 1 that could receive the RTS frame but could not receive the CTS frame receives the data frame of the communication device 1 on the receiving side. Even though there was no effect, NAV was set and the transmission opportunity was reduced.
[0248]
　In the conventional NAV setting method, since the setting is performed both when the RTS signal is received and when the CTS signal is received, transmission from a range that does not affect the data frame reception of the communication device 1 on the receiving side is suppressed. It had been done.
[0249]
　That is, if the CTS signal is not received after setting the NAV with the RTS signal, it is considered that there is little influence of interfering with the communication device 1 to which the signal is received.
[0250]
　On the other hand, according to the present technology, it is possible to set a network allocation vector (NAV) around the communication device 1 on the receiving side without performing RTS / CTS exchange.
[0251]
　Further, when the transmission power control is performed and the signal whose transmission power is reduced is received, the transmission power is not controlled around the communication device 1 on the receiving side from the overlapping BSS, and the signal is signaled at the maximum transmission power. Was sent, communication within the BSS could not be performed.
[0252]
　In other words, in overlapping BSS (OBSS), even if transmission power control is performed and transmission power is suppressed within the BSS to perform communication, it is not known that the transmission power control is being performed. In some cases, a signal was transmitted without performing transmission power control.
[0253]
　According to this technology, RSSI information at the time of data reception and data transmission power information are described in the signal in use, so the required S / N of the data reception destination is based on the values ​​of RSSI information and transmission power information. The ratio can be estimated, and it is possible to judge whether or not transmission with spatial reuse is performed. This makes it possible to set the transmission power within a range that does not affect data reception.
[0254]
　This technology can be applied to communication devices such as access points and communication devices that make up a wireless LAN system.
[0255]
　 The
　above-mentioned series of processes can be executed by hardware or software. When a series of processes are executed by software, the programs constituting the software are installed on the computer. Here, the computer includes a computer embedded in dedicated hardware, a general-purpose personal computer capable of executing various functions by installing various programs, and the like.
[0256]
　FIG. 27 is a block diagram showing a hardware configuration example of a communication device that executes the series of processes described above by a program.
[0257]
　In the communication device 300 shown in FIG. 27, the CPU (Central Processing Unit) 301, the ROM (Read Only Memory) 302, and the RAM (Random Access Memory) 303 are connected to each other via the bus 304.
[0258]
　The input / output interface 305 is also connected to the bus 304. An input unit 306, an output unit 307, a storage unit 308, a communication unit 309, and a drive 310 are connected to the input / output interface 305.
[0259]
　The input unit 306 includes, for example, a keyboard, a mouse, a microphone, a touch panel, an input terminal, and the like. The output unit 307 includes, for example, a display, a speaker, an output terminal, and the like. The storage unit 308 includes, for example, a hard disk, a RAM disk, a non-volatile memory, or the like. The communication unit 309 includes, for example, a network interface. The drive 310 drives a removable medium 311 such as a magnetic disk, an optical disk, a magneto-optical disk, or a semiconductor memory.
[0260]
　In the communication device configured as described above, the CPU 301 loads and executes the program stored in the storage unit 308 into the RAM 303 via the input / output interface 305 and the bus 304, for example. A series of processing is performed. The RAM 303 also appropriately stores data and the like necessary for the CPU 301 to execute various processes.
[0261]
　The program executed by the communication device (CPU301) can be recorded and applied to the removable media 311 as a package media or the like, for example. In that case, the program can be installed in the storage unit 308 via the input / output interface 305 by mounting the removable media 311 in the drive 310.
[0262]
　The program can also be provided via wired or wireless transmission media such as local area networks, the Internet, and digital satellite broadcasting. In that case, the program can be received by the communication unit 309 and installed in the storage unit 308.
[0263]
　In addition, this program can be pre-installed in the ROM 302 or the storage unit 308.
[0264]
　The program executed by the communication device may be a program in which processing is performed in chronological order in the order described in this specification, or at a required timing such as in parallel or when a call is made. It may be a program that is processed by.
[0265]
　In the present specification, the system means a set of a plurality of components (devices, modules (parts), etc.), and it does not matter whether all the components are in the same housing. Therefore, a plurality of devices housed in separate housings and connected via a network, and a device in which a plurality of modules are housed in one housing are both systems. ..
[0266]
　Further, the effects described in the present specification are merely examples and are not limited, and other effects may be obtained.
[0267]
　The embodiment of the present technology is not limited to the above-described embodiment, and various changes can be made without departing from the gist of the present technology.
[0268]
　For example, the present technology can have a cloud computing configuration in which one function is shared and jointly processed by a plurality of devices via a network.
[0269]
　Further, each step described in the above-mentioned flowchart can be executed by one device or can be shared and executed by a plurality of devices.
[0270]
　Further, when a plurality of processes are included in one step, the plurality of processes included in the one step can be executed by one device or shared by a plurality of devices.
[0271]
　Although the preferred embodiments of the present disclosure have been described in detail with reference to the accompanying drawings, the present disclosure is not limited to such examples. It is clear that anyone with ordinary knowledge in the field of technology to which this disclosure belongs can come up with various modifications or modifications within the scope of the technical ideas set forth in the claims. It is understood that these also belong to the technical scope of the present disclosure.
[0272]
　The present technology can also have the following configurations.
(1)
　and a construction unit that generates a data frame,
　a transmission unit that transmits the data frame to the destination communication device,
　during the transmission of the data frame, a control unit for performing interrupt control a predetermined time period sending
　a Communication device to be equipped.
(2) The
　above-
　described (1), further comprising a receiving unit that receives an in-use signal indicating that the transmission line is being used from the transmission destination communication device during the predetermined period during which the transmission is interrupted . Communication device.
(3) 　The communication device according to (1) or (2),
　wherein the predetermined period during which the transmission is interrupted includes a switching time for transmission / reception operations
.
(4)
　The communication device according to
　any one of (1) to (3) above, wherein the transmission unit transmits with transmission power that enables the communication device of the transmission destination to receive the data frame .
(5) The (5)
　header information generation unit
　that generates header information of the data frame in which information for specifying the communication device of the transmission destination of the data frame and information regarding the transmission power of the data frame are described is further provided. The communication device according to any one of 1) to (4).
(6)
　Transmission power that sets the transmission power that does not affect the reception of data frames of other communication devices based on the information of the received electric field strength when the in-use signal is received and the information of the received electric field strength described in the in-use signal. 　The communication device according to any one of (1) to (5)
　, further
　comprising a control unit , wherein the transmission unit transmits the data frame with the transmission power
.
(7)
　When the control unit does not detect a signal in use from another communication device for a predetermined time, the control unit determines that the
　transmission line is vacant, and the transmission unit determines that the transmission line is vacant. The communication device according to
　any one of (1) to (5) above, which transmits the data frame to the communication device of the transmission destination when it is determined to be present .
(8)
　A receiving unit that receives a transmitted data frame with a period for interrupting transmission is provided intermittently,
　and an in-use signal indicating that the transmission line is being used is transmitted during the period for interrupting the transmission. A
　communication device including a transmission unit .
(9) The
　above (8)
　further includes an in-use signal generation unit that adds a reception duration added to the data frame and calculated based on a parameter describing the duration of the data frame to the in-use signal. ).
(10)
　The in-use signal generation unit adds information on the received electric field strength when the data frame is received and information on the transmission power added to the header information of the data frame to the in-use signal
　(9). ).
(11) 　The communication device according to any one of (8) to (10) above, wherein the
　transmission unit transmits an end signal indicating the end when the reception of the data frame is completed
.
(12) The
　transmission unit of the
　above (8) to (11) transmits the in-use signal with a transmission power larger than the transmission power of the data frame in the communication device of the transmission source that has transmitted the data frame . The communication device according to any one.
(13) The
　signal in use is
　described in any one of (8) to (11) above , which includes information for identifying a network and information for identifying a communication device of a transmission source that has transmitted the data frame. Communication device.
(14) 　The communication device according to any one of (8) to (13) above, wherein the
　signal in use is configured with a parameter arrangement compatible with the preamble of the existing method
.
(15)
　It is transmitted from the second communication device that receives the data frame during the period during which the transmission is interrupted to the first communication device that transmits the transmitted data frame with a period for interrupting the transmission intermittently provided. A 　communication device including a receiving unit that receives an in-use signal indicating that the transmission line is being used, and
　a transmission control unit that controls transmission according to the reception status of the in-use signal
.
(16) 　The communication device according to (15)
　, wherein when the in-use signal is received, the transmission control unit controls the transmission so as to prohibit the transmission
.
(17) 　The communication device according to (15) or (16),
　wherein when the receiving unit does not receive the in-use signal, the transmission control unit controls transmission of another data frame
.
(18) Based on
　the received electric field strength when the in-use signal is received and the received electric field strength described in the in-use signal, the transmission power that does not affect the reception of the data frame by the second communication device is obtained. 　The communication device according to any one of (15) to (17),
　further including a transmission power control unit to be set ,
　wherein the transmission control unit controls transmission of the other data frame with the transmission power
.
(19)
　The transmission control unit sets a backoff time, which is a transmission waiting time, and when the backoff time expires, the transmission control unit controls transmission of the other data frame with the transmission power
　(18). ).
Code description
[0273]
　1, 1-1 to 1-5 Communication device, 11 Internet connection module, 12 Information input module, 13 Device control unit, 14 Information output module, 15 Wireless communication module, 101 Interface, 102 Transmission buffer, 103 Network management unit, 104 Transmission frame construction unit, 105 wireless communication control unit, 106 header information generation unit, 107 in-use signal generation unit, 108 transmission timing control unit, 109 transmission power control unit, 110 wireless transmission processing unit, 111 antenna control unit, 111-1A Antenna, 111-1B antenna, 112 wireless reception processing unit, 113 detection threshold control unit, 114 reception timing control unit, 115 in-use signal detection unit, 116 header information analysis unit, 117 reception data construction unit, 118 reception buffer
The scope of the claims
[Claim 1]
　A constructing unit for generating a data frame,
　the transmission unit that transmits the data frame to the destination communication device,
　during the transmission of the data frame, a control unit for performing interrupt control a predetermined time period sending
　communication device comprising ..
[Claim 2]
　The communication device according to
　claim 1, further comprising a receiving unit that receives an in-use signal indicating that the transmission line is being used from the communication device at the transmission destination during the predetermined period during which the transmission is interrupted .
[Claim 3]

　The communication device according to claim 2, 　wherein the predetermined period during which the transmission is interrupted includes a switching time of the transmission / reception operation .
[Claim 4]
　The communication device according to
　claim 2, wherein the transmission unit transmits with transmission power that enables the communication device at the transmission destination to receive the data frame .
[Claim 5]
　The
　second aspect of claim 2 further includes a header information generation unit that generates header information of the data frame in which information for specifying the communication device of the transmission destination of the data frame and information on transmission power of the data frame are described. Communication device.
[Claim 6]
　Transmission power that sets the transmission power that does not affect the reception of data frames of other communication devices based on the information of the received electric field strength when the in-use signal is received and the information of the received electric field strength described in the in-use signal. 　The communication device according 　to claim 2,
　further
comprising a control unit , wherein the transmission unit transmits the data frame with the transmission power
.
[Claim 7]
　When the control unit does not detect a signal in use from another communication device for a predetermined time, the control unit determines that the transmission line is vacant, and the
　transmission unit determines that the transmission line is vacant. The communication device according to
　claim 2 , wherein the data frame is transmitted to the communication device of the transmission destination when the data frame is transmitted .
[Claim 8]
　A receiver that receives a transmitted data frame with intermittent
　transmission interruption periods, and a transmitter that transmits an in-use signal indicating that a transmission line is being used during the transmission interruption period. A
　communication device equipped with.
[Claim 9]
　The
　eighth aspect of the present invention further comprises an in-use signal generation unit that adds a reception duration calculated based on a parameter describing the duration of the data frame added to the data frame to the in-use signal . Communication device.
[Claim 10]
　The use in the signal generating unit, the information of the received field strength at the time of receiving the data frame, and information of the transmission power which is added to the data frame header information is added to the in-use signal
　according to claim 9 The communication device described in.
[Claim 11]

　The communication device according 　to claim 8, wherein the transmission unit transmits an end signal indicating that the data frame has been received when the reception of the data frame is completed .
[Claim 12]
　The communication device according to
　claim 8, wherein the transmission unit transmits the in-use signal with a transmission power larger than the transmission power of the data frame in the communication device of the transmission source that has transmitted the data frame .
[Claim 13]
　The communication device according to
　claim 8, wherein the in-use signal includes information for identifying a network and information for identifying a communication device of a transmission source that has transmitted the data frame .
[Claim 14]

　The communication device according to claim 8, 　wherein the signal in use is composed of a parameter arrangement compatible with the preamble of the existing method .
[Claim 15]
　It is transmitted from the second communication device that receives the data frame during the period during which the transmission is interrupted to the first communication device that transmits the transmitted data frame with a period for interrupting the transmission intermittently provided. A 　communication device including a receiving unit that receives an in-use signal indicating that the transmission line is being used, and
　a transmission control unit that controls transmission according to the reception status of the in-use signal
.
[Claim 16]

　The communication device according 　to claim 15 , wherein when the in-use signal is received, the transmission control unit controls the transmission so as to prohibit the transmission .
[Claim 17]

　The communication device according 　to claim 15, wherein when the receiving unit does not receive the in-use signal, the transmission control unit controls transmission of another data frame .
[Claim 18]
　Transmission that sets the transmission power that does not affect the reception of the data frame by the second communication device based on the received electric field strength when the in-use signal is received and the received electric field strength described in the in-use signal. 　The communication device according 　to claim 17,
　further
comprising a power control unit , wherein the transmission control unit controls transmission of the other data frame with the transmission power
.
[Claim 19]
　The transmission control unit sets a back-off time is a transmission waiting time, when said back-off time has expired, the transmission control unit controls the transmission of the other data frames in the transmit power
　according to claim 18 The communication device described in.