JP5151737B2 - Wireless communication system, wireless communication apparatus, wireless communication method, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the efficiency of utilization of a band by making the collisions in communications reduce. <P>SOLUTION: A wireless communication system includes a first wireless communication device which is equipped with a transmission portion for transmitting a communication request signal; a receiving portion for receiving a response signal to the communication request signal; and a control portion for making the subsequent communications among the wireless communication devices of the destination stop, when the response signal shows waiting for transmitting; and a second wireless communications device which is a device having a receiving portion for receiving the communication request signal transmitted from the first wireless communication device, a transmission portion for transmitting a response signal to the communication request signal, and a controlling portion which causes the transmitting portion to wait for transmitting a signal, over a term indicated by the waiting-period information contained in the communication request signal, when a communication request signal which is not addressed to its device has been received, and which transmits a response signal indicating in-waiting for transmitting to the transmitting portion, when the transmitting portion is waiting for transmission, receiving a communication request signal addressed to its device. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a wireless communication system, a wireless communication apparatus, a wireless communication method, and a program.

  Recently, a wireless communication system in which a plurality of wireless communication devices are connected so as to be able to perform wireless communication with each other has become widespread. Such a wireless communication system is realized by a wireless technology such as IEEE (Institut of Electric and Electronic Engineers) 802.11 or Bluetooth (registered trademark).

  In such a wireless communication system, there is a problem that a communication collision may occur due to the presence of a hidden terminal located in a place that is recognized by one of the mutually connected wireless communication devices but not the other. . Thus, for example, in IEEE 802.11, an RTS / CTS (Request To Send / Clear To Send) method is introduced as a countermeasure against hidden terminals. In the RTS / CTS system, first, a wireless communication device that is a data transmission source transmits an RTS. The destination wireless communication apparatus that has received the RTS returns a CTS indicating that preparation for reception has been completed as a response to the RTS. Then, after receiving the CTS, the data transmission source wireless communication apparatus starts data transmission.

  Further, in the RTS / CTS system, a NAV (Network Allocation Vector) function for avoiding a collision with a packet transmitted from another wireless communication device during data transmission / reception, and a wireless communication device that has started communication are in communication. A TXOP (Transmission Opportunity) function for obtaining priority has been introduced.

  Patent Document 1 below discloses an example of a technique for reducing packet collisions by restricting data transmission to other wireless communication apparatuses in the remaining period of the transmission permission period in the TXOP function.

JP 2006-197032 A

  However, in the currently installed TXOP function, a wireless communication device waiting for transmission avoids a communication collision without returning a CTS even if it receives an RTS, while returning an ACK when receiving data. May cause communication collisions.

  Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide a new and improved wireless communication that can reduce communication collision and improve bandwidth utilization efficiency. A communication system, a wireless communication apparatus, a wireless communication method, and a program are provided.

  In order to solve the above problems, according to an aspect of the present invention, communication including transmission source information for identifying a transmission source wireless communication device or destination information for identifying a destination wireless communication device, and predetermined waiting period information A transmission unit that transmits a request signal, a reception unit that receives a response signal to the communication request signal, and a wireless communication device that is the destination of the communication request signal is waiting for transmission in the response signal received by the reception unit Is transmitted from the first wireless communication device, and a first wireless communication device including a control unit that stops subsequent communication with the destination wireless communication device. A receiving unit that receives the communication request signal, a transmitting unit that transmits a response signal to the communication request signal, and a communication request signal when the receiving unit receives a communication request signal that is not addressed to its own device. When the transmission unit waits for signal transmission over the period indicated by the waiting period information included in the solicitation signal, and the transmission unit is waiting for transmission when the reception unit receives a communication request signal addressed to its own device Includes a second wireless communication apparatus including a control unit that causes the transmission unit to transmit a response signal indicating that the own apparatus is waiting for transmission.

  According to such a configuration, the transmission unit of the first wireless communication apparatus performs communication including transmission source information for identifying the transmission source wireless communication apparatus or destination information for identifying the destination wireless communication apparatus, and predetermined waiting period information. Send a request signal. The receiving unit of the second wireless communication apparatus receives the communication request signal transmitted from the first wireless communication apparatus. Then, in the second wireless communication device, when the received communication request signal is not addressed to the own device, the control unit causes the signal transmission to wait for the period indicated by the waiting period information included in the communication request signal. It is done. In the second wireless communication apparatus, when the received communication request signal is addressed to the own apparatus and the own apparatus is waiting for transmission, a response signal indicating that the own apparatus is waiting for transmission is sent to the transmission unit. Send. In the first wireless communication device, when the response signal for the transmitted communication request signal is received, if the response signal indicates that the wireless communication device that is the destination of the communication request signal is waiting for transmission, control is performed. The subsequent communication with the destination wireless communication apparatus is stopped by the unit.

  The response signal includes waiting period information, and the control unit of the second wireless communication apparatus sets the waiting period information of the response signal indicating that the own apparatus is waiting for transmission to zero. May be.

  The response signal includes standby period information, and the control unit of the second wireless communication device indicates the standby period information of the response signal indicating that the own device is waiting for transmission. A value that is not recognized as a value may be set.

  In addition, the control unit of the first wireless communication device may indicate that the response signal received by the receiving unit indicates that the wireless communication device that is the destination of the communication request signal is waiting to be transmitted. The transmission standby release signal may be transmitted to the transmission unit.

  The second wireless communication apparatus further includes a data processing unit that stores transmission source information or destination information included in the communication request signal received by the reception unit in a storage medium as registration station information, The control unit of the second wireless communication device includes transmission source information included in the communication request signal when the transmission unit is waiting for transmission when the reception unit receives a communication request signal addressed to the device. Alternatively, only when the destination information does not match the registered station information stored in the storage medium, a response signal indicating that the own apparatus is waiting for transmission may be transmitted to the transmission unit.

  Further, the control unit of the second wireless communication apparatus may use a MAC address corresponding to the transmission source information or the destination information as the registration station information.

  The control unit of the second wireless communication apparatus may use an index number corresponding to the transmission source information or the destination information as the registration station information.

  In order to solve the above-described problem, according to another aspect of the present invention, transmission source information for identifying a transmission source wireless communication device or destination information for identifying a destination wireless communication device, and predetermined waiting period information are included. A transmission unit that transmits a communication request signal, a reception unit that receives a response signal to the communication request signal, and a wireless communication device that is the destination of the communication request signal in the response signal received by the reception unit is waiting for transmission If it is indicated, a wireless communication device is provided that includes a control unit that stops subsequent communication with the wireless communication device of the destination.

  In order to solve the above-described problem, according to another aspect of the present invention, there is provided a communication request signal transmitted from another wireless communication device, which is transmission source information for identifying the wireless communication device of the transmission source or wireless of the destination A receiving unit that receives a communication request signal including destination information for identifying a communication device and predetermined waiting period information, a transmitting unit that transmits a response signal to the communication request signal, and a communication in which the receiving unit is not addressed to the own device When a request signal is received, when the transmission unit waits for signal transmission over a period indicated by the standby period information included in the communication request signal, and the reception unit receives a communication request signal addressed to the own device And a control unit that causes the transmission unit to transmit a response signal indicating that the transmission unit is waiting for transmission.

  In order to solve the above-mentioned problem, according to another aspect of the present invention, from the first wireless communication device, transmission source information for identifying the wireless communication device of the transmission source or destination information for identifying the wireless communication device of the destination, And a step of transmitting a communication request signal including predetermined waiting period information, a step of receiving the communication request signal transmitted from the first wireless communication device in a second wireless communication device, and a second wireless communication device. In the communication device, when the received communication request signal is not addressed to the own device, the step of waiting for signal transmission over the period indicated by the waiting period information included in the communication request signal, and the second wireless communication device A step of transmitting a response signal indicating that the device is waiting for transmission when the received communication request signal is addressed to the device and the device is waiting for transmission; Receiving a response signal for the transmitted communication request signal in one wireless communication device; and in the first wireless communication device, a wireless communication device that is the destination of the communication request signal is waiting for transmission based on the received response signal A wireless communication method comprising: suspending subsequent communication with the destination wireless communication device if indicated to be in progress.

  In order to solve the above-described problem, according to another aspect of the present invention, a computer that controls a wireless communication device is configured to send source information for identifying a wireless communication device as a transmission source or destination information for identifying a wireless communication device as a destination. And a transmission unit that transmits a communication request signal including predetermined waiting period information, a reception unit that receives a response signal to the communication request signal, and a destination of the communication request signal in the response signal received by the reception unit If the wireless communication apparatus is waiting for transmission, a program for causing the wireless communication apparatus to function as a control unit that stops subsequent communication with the destination wireless communication apparatus is provided. .

  In order to solve the above-described problem, according to another aspect of the present invention, a computer that controls a wireless communication apparatus is a communication request signal transmitted from another wireless communication apparatus, and the transmission source wireless communication apparatus is A receiving unit that receives a communication request signal including transmission source information to be identified or destination information that identifies a destination wireless communication device and predetermined waiting period information; a transmitting unit that transmits a response signal to the communication request signal; When the receiving unit receives a communication request signal that is not addressed to its own device, the transmitting unit waits for transmission of the signal over the period indicated by the waiting period information included in the communication request signal, and the receiving unit When the transmission unit is waiting for transmission when receiving a communication request signal addressed to it, the control unit causes the transmission unit to transmit a response signal indicating that its own device is waiting for transmission. Program for causing a is provided.

  As described above, according to the wireless communication system, the wireless communication apparatus, the wireless communication method, and the program according to the present invention, it is possible to reduce communication collisions and improve bandwidth utilization efficiency.

  Exemplary embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol.

The “best mode for carrying out the invention” will be described in the following order.
[1] Overview of wireless communication system [2] Problems of wireless communication system related to the present invention [3] Description of one embodiment of the present invention [3-1] Basic configuration of wireless communication apparatus [3-2] Function as start station [3-3] Function as response station [3-4] Flow of communication processing between start station and response station [3-5] Registration of transmission source information / destination information [4] Summary

[1] Overview of Radio Communication System First, an overview of a radio communication system 1 according to an embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is an explanatory diagram showing an example of the configuration of the wireless communication system 1. Referring to FIG. 1, a wireless communication system 1 includes wireless communication devices 10A to 10E. The ranges indicated by dotted lines around the wireless communication devices 10A to 10E represent the radio wave reachable ranges 12A to 12E in which the wireless communication devices 10A to 10E can perform wireless communication, respectively.

  In the wireless communication system 1, the wireless communication device 10A can wirelessly communicate with the wireless communication device 10B and the wireless communication device 10C included in the radio wave reachable range 12A. The wireless communication device 10B can perform wireless communication with the wireless communication device 10A and the wireless communication device 10D included in the radio wave reachable range 12B. Similarly, the wireless communication device 10C can wirelessly communicate with the wireless communication device 10A and the wireless communication device 10E. Further, the wireless communication device 10D can perform wireless communication with the wireless communication device 10B. Further, the wireless communication device 10E can perform wireless communication with the wireless communication device 10C. As described above, the wireless communication devices 10 </ b> A to 10 </ b> E perform wireless communication with the devices included in the respective radio wave reachable ranges 12 </ b> A to 12 </ b> E, thereby forming one wireless network as the wireless communication system 1.

  In the present specification, when it is not necessary to distinguish the radio communication devices 10A to 10E, the radio communication device 10 is simply referred to. .

  The wireless communication device 10 includes information processing devices such as PCs (Personal Computers) and workstations, mobile phone terminals and PDAs (Personal Digital Assistants), terminal devices such as game terminals, home appliances such as DVD recorders and video decks, Alternatively, it may be a wireless communication module connected to these devices, devices and the like.

  Heretofore, an example of the configuration of the wireless communication system 1 has been described. Next, an example of communication using the RTS / CTS method using the NAV function in the wireless communication system 1 will be described.

  FIG. 2 is an explanatory diagram showing, as an example, a state of communication by the RTS / CTS method. FIG. 3 is an explanatory diagram showing a format example of each frame.

  FIG. 2 shows a case where the radio communication devices 10B and 10C are included in the radio wave reachable range 12A of the radio communication device 10A, and the radio communication devices 10A and 10D are included in the radio wave reachable range 12B of the radio communication device 10B.

  In the example illustrated in FIG. 2, first, RTS 21 as an example of a communication request signal is transmitted from the wireless communication device 10A to the wireless communication device 10B. Then, the wireless communication device 10B that has received the RTS 21 transmits a CTS 22 as an example of a response signal to the wireless communication device 10A. When the wireless communication device 10A receives the CTS 22 from the wireless communication device 10B, the wireless communication device 10A determines that the reception preparation of the wireless communication device 10B is completed and transmits the data 23. When the wireless communication device 10B has successfully received the data 23 from the wireless communication device 10A, the wireless communication device 10B transmits an ACK 27 as an example of an acknowledgment signal to the wireless communication device 10A.

  As shown in FIG. 3, the RTS 21 includes a FrameControl 210, a Duration 212, an RA 214, a TA 216, and an FCS 218. The FrameControl 210 includes information regarding a frame, for example, includes information indicating that the frame is an RTS 21 frame. The Duration 212 includes standby period information indicating a period during which the wireless communication device 10 that has received the RTS 21 is in a transmission standby state, for example. RA 214 indicates address information of the wireless communication device 10 that is the transmission destination (destination) of the RTS 21, and TA 216 indicates address information of the wireless communication device 10 that is the transmission source of the RTS 21. Further, the FCS 218 includes information for detecting an error in the RTS 21 in the wireless communication device 10 that is the transmission destination of the RTS 21.

  Therefore, in the example of FIG. 2, the wireless communication device 10 </ b> C that has received the RTS 21 transmitted from the wireless communication device 10 </ b> A to the wireless communication device 10 </ b> B waits for transmission of a signal for the period described in the Duration 212 of the RTS 21. 50 is set.

  The CTS 22 includes a Frame Control 222, a Duration 224, an RA 226, and an FCS 228 as shown in FIG. The FrameControl 222 includes information on the frame, for example, includes information indicating that the frame is a CTS 22 frame. Duration 224 includes, for example, standby period information indicating a period in which the wireless communication apparatus 10 that has received the CTS 22 is in a transmission standby state. RA 226 indicates the address information of the wireless communication apparatus 10 that is the transmission destination (destination) of the CTS 22. The FCS 228 is information for detecting an error in the CTS 22 in the wireless communication device 10 that is the transmission destination of the CTS 22.

  Therefore, in the example of FIG. 2, the wireless communication device 10D that has received the CTS 22 transmitted from the wireless communication device 10B to the wireless communication device 10A waits for transmission of a signal for the period described in the Duration 224 of the CTS 22 (NAV). 50 is set.

  As described above, when the wireless communication device 10A attempts to transmit the data 23 to the wireless communication device 10B, the surrounding wireless communication devices 10C and 10D enter the transmission standby state 50. Therefore, the possibility that the data 23 transmitted from the wireless communication device 10A and the ACK 27 transmitted from the wireless communication device 10B collide with other signals can be suppressed.

  Note that the standby period information described in Duration 212 and Duration 224 may be information indicating a time interval starting from the time of reception of a signal for causing another wireless communication apparatus 10 to enter the transmission standby state 50. Further, even if the standby period information is information indicating an end time for ending the transmission standby state 50 of the other wireless communication device 10, a start time and an end time for causing the other wireless communication device 10 to enter the transmission standby state 50. It may be information indicating.

  In addition, when the wireless communication device 10C is already in the transmission standby state 50 before receiving the RTS 21, the wireless communication device 10C includes the remaining time in the transmission standby state 50 and the standby period information described in the Duration 212 of the RTS 21. Compare When the standby period information described in the Duration 212 of the RTS 21 is longer, the wireless communication device 10C updates the remaining time in the transmission standby state 50 using the standby period information described in the Duration 212 of the RTS 21. To do.

  3, the data 23 includes a Frame Control 232, a Duration / ID 234, an Address A 236, an Address B 238, an Address C 240, a Sequence control 242, an Address D 244, a Frame body 246, and an FCS 248. Thus, since the data 23 also includes the Duration / ID 234 in which the waiting period information is described, if the wireless communication device 10 that has received the data 23 is not the destination of the data 23, the wireless communication that has received the data 23 The apparatus 10 shifts to the transmission standby state 50.

  The ACK 27 includes a Frame Control 272, a Duration 274, an RA 276, and an FCS 278, as shown in FIG. Thus, since the ACK 27 also includes the Duration / ID 264 in which the waiting period information is described, when the wireless communication device 10 that has received the ACK 27 is not the destination of the ACK 27, the wireless communication device 10 that has received the ACK 27 The process shifts to the transmission standby state 50.

  In addition, the management frame (Management) 25, the BA (Block Ack) 28, or the BAR (Block Ack Request) 29 shown in FIG. 3 includes a field for Duration or Duration / ID, respectively. Then, if the wireless communication device 10 that has received these frames is not the destination device, the wireless communication device 10 enters the transmission standby state 50 for a period corresponding to the standby period information described in the field.

  Next, a communication example using the TXOP function in the wireless communication system 1 will be described with reference to FIG. FIG. 4 is an explanatory diagram showing an example of a state of communication using the TXOP function.

  FIG. 4 shows a case where the radio communication device 10B is included in the radio wave reachable range 12A of the radio communication device 10A, and the radio communication device 10A is included in the radio wave reachable range 12B of the radio communication device 10B.

  In the example of FIG. 4A, the wireless communication device 10A transmits an RTS 21 to the wireless communication device 10B and attempts to acquire TXOP (transmission permission period) 20. The wireless communication device 10B that has received the RTS 21 from the wireless communication device 10A transmits the CTS 22. The wireless communication device 10A that has received the CTS 22 from the wireless communication device 10B determines that the TXOP 20 has been acquired, and then transmits data 23. Furthermore, the wireless communication device 10B that has received the data 23 transmits an ACK 27. Thereafter, transmission / reception of the data 23 and the ACK 27 between the wireless communication apparatuses 10A and 10B is continued until the remaining period of the TXOP 20 disappears.

  In FIG. 4A, the management frame 25 shown in FIG. 3 may be transmitted instead of the data 23. Instead of the data 23, an A-MPDU (Aggregation-MAC Protocol Data Unit) in which a plurality of data frames defined in the IEEE 802.11n system are combined may be transmitted. In this case, the BA 28 shown in FIG. 3 is transmitted instead of the ACK 27 as a response signal from the wireless communication device 10B.

  Thereafter, although not particularly specified in the present specification, the data 23 can be replaced with, for example, the management frame 25 or A-MPDU, and the ACK 27 can be replaced with, for example, the BA 28.

  In the example of FIG. 4B, the wireless communication device 10A transmits data 23 to the wireless communication device 10B and attempts to acquire TXOP (transmission permission period) 20. The wireless communication device 10B that has received the data 23 from the wireless communication device 10A transmits the ACK 27 regardless of whether or not the device itself is waiting for transmission. The wireless communication device 10A that has received the ACK 27 from the wireless communication device 10B determines that the TXOP 20 has been acquired, and further transmits data 23. Thereafter, transmission / reception of the data 23 and the ACK 27 between the wireless communication apparatuses 10A and 10B is continued until the remaining period of the TXOP 20 disappears.

  In the example of FIG. 4C, the wireless communication device 10A transmits a BAR 29 to the wireless communication device 10B and attempts to acquire TXOP (transmission permission period) 20. The wireless communication device 10B that has received the BAR 29 from the wireless communication device 10A transmits the BA 28 regardless of whether or not the device itself is waiting for transmission. The wireless communication device 10A that has received the BA 28 from the wireless communication device 10B determines that the TXOP 20 has been acquired, and transmits the A-MPDU 23. Thereafter, transmission / reception of the A-MPDU 23 and the BA 28 between the wireless communication apparatuses 10A and 10B is continued until the remaining period of the TXOP 20 disappears.

  Which communication procedure to use among the communication procedures shown in FIGS. 4A to 4C is left to selection of a start station (in the case of FIG. 4, the wireless communication device 10A) to start communication. At this time, when any communication procedure is selected, the waiting period information is written in each frame as described above. Further, the MAC address as destination information for identifying the destination device is written in the RA field or Address A field of each frame, and the MAC address as the source information for identifying the source device is written in the TA field or Address B field.

[2] Problems of Radio Communication System Related to the Present Invention The outline of the radio communication system 1 according to the embodiment of the present invention has been described above. Next, problems of the wireless communication system related to the present invention will be described with reference to FIGS. 5 and 6.

  FIG. 5 is an explanatory diagram illustrating, as an example, a state in which communication using the RTS / CTS method is performed between the wireless communication device 10B and the wireless communication device 10D. The positional relationship between the wireless communication devices A to D in FIG. 5 is equivalent to the positional relationship illustrated in FIG. In this case, the wireless communication device 10C is a so-called hidden terminal when viewed from the wireless communication device 10B.

  In the example of FIG. 5, first, the wireless communication device 10B transmits an RTS 21 destined for the wireless communication device 10D. The RTS 21 transmitted from the wireless communication device 10B is received by the wireless communication devices 10D and 10A located within the radio wave reachable range 12B.

  When the wireless communication device 10A receives the RTS 21 transmitted from the wireless communication device 10B, the destination information included in the RTS 21 does not correspond to the device itself, so the transmission standby state (NAV) 50 according to the standby period information included in the Duration 212 of the RTS 21. It becomes.

  In addition, the wireless communication device 10D that has received the RTS 21 from the wireless communication device 10B returns a CTS 22 to the wireless communication device 10B. Thereafter, transmission / reception of the data 23 and the ACK 27 between the wireless communication apparatuses 10B and 10D is continued until the remaining period of the TXOP disappears.

  At this time, the RTS 21 addressed to the wireless communication device 10A may be transmitted from the wireless communication device 10C while data transmission / reception between the wireless communication devices 10B and 10D is continued. However, since the wireless communication device 10A is already in the transmission standby state 50 as described above, the CTS 22 is not returned from the wireless communication device 10A to the wireless communication device 10C. Thereby, data transmission / reception between the wireless communication devices 10B and 10D is not disturbed.

  On the other hand, FIG. 6 is an explanatory diagram illustrating another example in which communication by the RTS / CTS method is performed between the wireless communication device 10B and the wireless communication device 10D. The positional relationship between the wireless communication devices 10A to 10D in the example of FIG. 6 is also equivalent to the positional relationship illustrated in FIG.

  In the example of FIG. 6, first, the wireless communication device 10B transmits an RTS 21 destined for the wireless communication device 10D. The RTS 21 transmitted from the wireless communication device 10B is received by the wireless communication devices 10D and 10A located within the radio wave reachable range 12B.

  When the wireless communication device 10A receives the RTS 21 transmitted from the wireless communication device 10B, the destination information included in the RTS 21 does not correspond to the device itself, so the transmission standby state (NAV) 50 according to the standby period information included in the Duration 212 of the RTS 21. It becomes.

  On the other hand, the wireless communication device 10D that has received the RTS 21 from the wireless communication device 10B returns a CTS 22 to the wireless communication device 10B. Thereafter, transmission / reception of the data 23 and the ACK 27 between the wireless communication devices 10B and 10D is continued.

  At this time, the data 23 addressed to the wireless communication device 10A may be transmitted from the wireless communication device 10C while data transmission / reception between the wireless communication devices 10B and 10D is continued. Whether or not the data 23 can be normally received by the wireless communication device 10A depends on the power level of the signal, the ratio of overlap time, and the like. When the wireless communication device 10A receives the data 23 addressed to itself, the wireless communication device 10A ignores the waiting for transmission and transmits an ACK 27 to the wireless communication device 10C. Accordingly, the wireless communication device 10C determines that the TXOP has been acquired, and subsequently transmits / receives the data 23 and the ACK 27 to / from the wireless communication device 10A. Then, the ACK 27 transmitted from the wireless communication device 10A collides with the ACK 27 transmitted from the wireless communication device 10D, and communication between the wireless communication devices 10B and 10D started earlier may be interrupted.

  The TXOP acquisition procedure in which the RTS / CTS between the wireless communication devices 10C and 10A shown in FIG. 6 is omitted has an advantage that the overhead is small. However, such a procedure can interfere with previously initiated communications that should be prioritized, as described above.

[3] Description of One Embodiment of the Present Invention Hereinafter, a radio communication apparatus system 1 according to one embodiment of the present invention will be described in detail with reference to FIGS.

[3-1] Basic Configuration of Radio Communication Device FIG. 7 is an explanatory diagram showing an example of the hardware configuration of the radio communication device 10 according to the present embodiment. Referring to FIG. 7, the wireless communication device 10 includes a CPU (Central Processing Unit) 101, a ROM (Read Only Memory) 102, a RAM (Random Access Memory) 103, a host bus 104, a bridge 105, an external bus 106, an interface 107, An input device 108, an output device 110, a storage device 111, a drive 112, and a communication device 115 are provided.

  The CPU 101 functions as an arithmetic processing device and a control device, and controls the overall operation in the wireless communication device 10 according to various programs. The CPU 101 may be a microprocessor. The ROM 102 stores programs and calculation parameters used by the CPU 101. The RAM 103 primarily stores programs used in the execution of the CPU 101, parameters that change as appropriate during the execution, and the like. These are connected to each other by a host bus 104 including a CPU bus.

  The host bus 104 is connected via a bridge 105 to an external bus 106 such as a PCI (Peripheral Component Interconnect / Interface) bus. Note that the host bus 104, the bridge 105, and the external bus 106 are not necessarily separated from each other, and these functions may be mounted on one bus.

  The input device 108 includes input means for inputting information by a user such as a mouse, keyboard, touch panel, button, or microphone, and an input control circuit that generates an input signal based on the user input and outputs the input signal to the CPU 101. Is done.

  The output device 110 includes, for example, a display device such as a CRT (Cathode Ray Tube), a liquid crystal display, an OLED (Organic Light Emitting Display) or a lamp, or an audio output device such as a speaker.

  The storage device 111 is a data storage device configured as an example of a storage unit of the wireless communication device 10 according to the present embodiment. The storage device 111 is configured by, for example, an HDD (Hard Disk Drive) or a flash memory. The storage device 111 stores programs executed by the CPU 101 and various data, or a MAC address of the wireless communication device 10 described later.

  The drive 112 corresponds to, for example, a storage medium reader / writer and is built in or externally attached to the wireless communication apparatus 10. The drive 112 reads information recorded on a removable storage medium 21 such as a magnetic disk, an optical disk, a magneto-optical disk, or a semiconductor memory to be loaded and outputs the information to the RAM 103.

  The communication device 115 is a communication interface configured with, for example, a communication device for connecting to the communication network 13. The communication device 115 may be, for example, a device that supports wireless communication using a wireless LAN (Local Area Network).

  So far, the hardware configuration of the wireless communication apparatus 10 according to the present embodiment has been described. Next, the logical configuration of the wireless communication device 10 will be described with reference to FIG.

  FIG. 8 is a block diagram showing a logical configuration of the wireless communication apparatus 10 according to the present embodiment. Referring to FIG. 8, the wireless communication apparatus 10 includes an antenna 116, a transmission data generation unit 120, a wireless transmission unit 124, a wireless reception unit 128, a reception data analysis unit 132, a data buffer 136, an interface 140, a control unit 144, data processing. Unit 148 and storage unit 152.

  The antenna 116 transmits a radio signal to the other radio communication device 10 and receives a radio signal from the other radio communication device 10. Examples of the radio signal include each frame such as RTS 21, CTS 22, data 23, or ACK 27 shown in FIG. 3.

  The transmission data generation unit 120 generates a frame to be transmitted based on control by the control unit 144. For example, the transmission data generation unit 120 generates a data 23 at a predetermined timing by adding a MAC header to a data body (for example, Framebody 246) input from the data buffer 136. Further, a control frame that does not include a data body such as RTS 21, CTS 22, or ACK 27 is generated by the transmission data generation unit 120 without receiving an input from the data buffer 136.

  The wireless transmission unit 124 performs wireless processing such as modulation, frequency conversion, and amplification on the frame generated by the transmission data generation unit 120 to generate a wireless signal. The wireless transmission unit 124 functions as the transmission unit 126 in cooperation with the transmission data generation unit 120. The wireless signal generated by the wireless transmission unit 124 is transmitted from the antenna 116 to another wireless communication device 10.

  The wireless reception unit 128 performs processing such as amplification, frequency conversion, and demodulation on the wireless signal received by the antenna 116. The reception data analysis unit 132 analyzes the MAC header of the frame demodulated by the wireless reception unit 128 and performs error detection. Then, the reception data analysis unit 132 transfers information (for example, Framebody 246) determined to be transferred to the external device to the data buffer 136 and the interface 140. The reception data analysis unit 132 functions as the reception unit 134 in cooperation with the wireless reception unit 128.

  The data buffer 136 temporarily stores information input from the interface 140 and information input from the received data analysis unit 132.

  The control unit 144 executes a function as a start station or a function as a response station of the radio communication device 10 described in detail later, triggered by reception of a radio signal or an instruction from a user.

  The data processing unit 148 acquires information included in the radio signal received by the antenna 116 and causes the storage unit 152 to store the information. For example, transmission source information for identifying a transmission source device, destination information for identifying a destination device, standby period information, and the like are stored in the storage unit 152 by the data processing unit 148.

  The storage unit 152 is configured using, for example, the storage device 111 illustrated in FIG. 7, and holds and stores information necessary for the operation of the control unit 144.

  So far, the basic configuration of the wireless communication device 10 according to the present embodiment has been described. Next, the wireless communication device 10 is divided into a case where the wireless communication device 10 functions as a start station for starting communication with another wireless communication device 10 and a case where the wireless communication device 10 functions as a response station for responding to a communication request from the start station. The function of the communication device 10 will be described in more detail.

  Note that the hardware configuration and logical configuration of the wireless communication device 10 described with reference to FIGS. 7 and 8 are common to the case where the wireless communication device 10 functions as a start station and the function of a response station. Applicable.

[3-2] Function as Start Station First, a case where the wireless communication apparatus 10 functions as a start station that starts communication with another wireless communication apparatus 10 will be described. In the following description, it is assumed that the wireless communication device 10B indicates a start station and the wireless communication device 10D indicates a response station.

  When the wireless communication device 10B functions as a start station, first, a communication request signal destined for the wireless communication device 10D is transmitted from the transmission unit 126 via the antenna 116. The communication request signal includes transmission source information for identifying the wireless communication device 10B as the transmission source, destination information for identifying the wireless communication device 10D as the destination, predetermined waiting period information, and the like.

  The communication request signal is implemented, for example, as RTS 21 or BAR shown in FIG. Further, as in the case shown in FIG. 4B, the data 23 transmitted first may be handled as a communication request signal.

  When the communication request signal is transmitted from the transmission unit 126, the wireless communication device 10B waits for transmission of a response signal from the wireless communication device 10D that is the destination. Then, when a response signal is transmitted from the wireless communication device 10D, the response signal is received by the reception unit 134 via the antenna 116 of the wireless communication device 10B. The response signal is implemented as, for example, CTS 22, ACK 27, or BA 28 shown in FIG.

  When the response signal is received by the reception unit 134, the control unit 144 normally determines that the TXOP has been acquired. Here, when the response signal from the wireless communication device 10D is, for example, the CTS 22 shown in FIG. 3, the Duration 224 of the CTS 22 includes standby period information. Therefore, the control unit 144 of the wireless communication device 10B that is the start station can determine the transmission permission period in TXOP from the standby period information included in the response signal.

  At this time, if the wireless communication device 10D is in a transmission standby state in order to prioritize the communication of another wireless communication device 10, a value that cannot be handled as a transmission permission period is set in the standby period information of the response signal. Yes. In this case, the control unit 144 of the wireless communication device 10B determines that the wireless communication device 10D is waiting for transmission and cannot communicate, and stops transmission / reception of subsequent data.

  Further, the control unit 144 of the wireless communication device 10B may cause the transmission unit 126 to transmit a transmission standby release signal when determining that the wireless communication device 10D is in transmission standby. That is, as a result of the transmission of the communication request signal from the transmission unit 126 of the wireless communication device 10B, there is a possibility that another wireless communication device 10 included in the radio wave reachable range 12B is in a transmission standby state by the NAV function. Therefore, it is preferable to transmit a transmission standby release signal from the transmission unit 126 of the wireless communication device 10B and return the other wireless communication device 10 in the transmission standby state to a communicable state. As the transmission standby release signal, for example, a CF-End (Contention-Free End) signal made available by any communication station in IEEE 802.11n may be used.

  On the other hand, if a value that can be handled as the transmission permission period is set in the waiting period information of the response signal, it is determined that the wireless communication device 10D can communicate. In that case, the control unit 144 of the wireless communication device 10B causes the transmission unit 126 to transmit data to be transmitted to the wireless communication device 10D to the wireless communication device 10D.

[3-2] Function as Response Station Next, a case where the wireless communication apparatus 10 functions as a response station that responds to a communication request from the start station will be described. As in the above description, the wireless communication device 10B is a start station and the wireless communication device 10D is a response station.

  When the communication request signal is transmitted from the wireless communication device 10B, the communication request signal is received by the receiving unit 134 of the wireless communication device 10D. If there is no error in the received communication request signal, the received data analysis unit 132 extracts the MAC header value including the destination information and passes it to the control unit 144. Then, the control unit 144 of the wireless communication device 10D determines whether or not the destination of the received signal is the own device based on the received destination information.

  Here, when the destination of the received communication request signal is not its own device, the control unit 144 causes the transmission unit 126 to wait for signal transmission over the period indicated by the standby period information included in the communication request signal. At this time, if the device itself is already waiting for transmission, the wireless communication device 10D compares the remaining transmission waiting period with the received waiting period information. If the received waiting period information is longer, the wireless communication device 10D Update the waiting period.

  When the destination of the received communication request signal is the own device, the control unit 144 further performs different processing depending on whether the own device is currently waiting for transmission. That is, when the device itself is not currently waiting for transmission, the control unit 144 causes the transmission unit 126 to transmit a normal response signal to the wireless communication device 10B. At this time, the response signal can include waiting period information.

  On the other hand, when the own device is currently waiting for transmission, the control unit 144 causes the transmission unit 126 to transmit a response signal indicating that the own device is waiting for transmission. For example, the control unit 144 can indicate that the own apparatus is waiting for transmission by setting a value that cannot be handled as the transmission permission period in the Duration 224 of the CTS 22 illustrated in FIG. 3.

  As a value that cannot be handled as the transmission permission period, for example, zero can be set. If the communication station determines that the value of the Duration (Duration / ID) field of the frame received immediately before by the wireless communication device 10 is the maximum transmission permission period, additional processing is performed by setting the field to zero. Subsequent communication can be stopped without necessity. Further, for example, a value that cannot be recognized as the transmission permission period may be set such as “32769” that is unused in the communication specification.

  Up to this point, the functions of the wireless communication device 10 according to the present embodiment as a start station and a response station have been described. Next, the flow of communication processing in the wireless communication system 1 performed by the start station and the response station in cooperation with each other will be described with reference to FIGS. 9 and 10.

[3-4] Flow of Communication Processing Between Start Station and Response Station FIG. 9 is an explanatory diagram illustrating an example of the flow of communication processing performed between the wireless communication devices 10A to 10D. In the example of FIG. 9, the wireless communication devices 10B and 10C serve as the above-described start station, and the wireless communication devices 10A and 10D serve as response stations. The positional relationship between the wireless communication devices 10A to 10D in FIG. 9 is equivalent to the positional relationship illustrated in FIG.

  In the example of FIG. 9, first, the wireless communication device 10B transmits an RTS 21 whose destination is the wireless communication device 10D. The RTS 21 transmitted from the wireless communication device 10B is received by the wireless communication devices 10D and 10A located within the radio wave reachable range 12B.

  When the wireless communication device 10A receives the RTS 21 transmitted from the wireless communication device 10B, the destination information included in the RTS 21 does not correspond to the device itself, so the transmission standby state (NAV) 50 according to the standby period information included in the Duration 212 of the RTS 21. It becomes.

  On the other hand, the wireless communication device 10D that has received the RTS 21 from the wireless communication device 10B returns a CTS 22 to the wireless communication device 10B. Thereafter, transmission / reception of the data 23 and the ACK 27 between the wireless communication devices 10B and 10D is continued.

  Here, while data transmission / reception between the wireless communication devices 10B and 10D continues, the data 23 addressed to the wireless communication device 10A may be transmitted from the wireless communication device 10C. When the wireless communication device 10A receives the data 23 addressed to itself, the wireless communication device 10A transmits an ACK 27 to the wireless communication device 10C. At this time, since the wireless communication device 10A is waiting for transmission at that time, unlike the example shown in FIG. 6, the wireless communication device 10A includes a transmission permission period in the waiting period information of the response signal transmitted to the wireless communication device 10C. Set a value that cannot be handled as.

  Thereafter, the wireless communication device 10C that has received the response signal transmitted from the wireless communication device 10A stops the subsequent transmission of the data 23 because the response signal indicates that the wireless communication device 10A is waiting for transmission. . As a result, further ACK 27 is prevented from being transmitted from the wireless communication device 10A, and the possibility that communication between the wireless communication devices 10B and 10D is interrupted is reduced.

  Next, FIG. 10 is an explanatory diagram illustrating an example of a flow of communication processing performed between the wireless communication devices 10A to 10E. In FIG. 10, the wireless communication devices 10B and 10C serve as the above-described starting stations, and the wireless communication devices 10A, 10D, and 10E serve as response stations. The positional relationship between the wireless communication devices 10A to 10E in FIG. 10 is equivalent to the positional relationship illustrated in FIG.

  In the example of FIG. 10, first, the wireless communication device 10B transmits an RTS 21 that is destined for the wireless communication device 10D. The RTS 21 transmitted from the wireless communication device 10B is received by the wireless communication devices 10D and 10A located within the radio wave reachable range 12B.

  When the wireless communication device 10A receives the RTS 21 transmitted from the wireless communication device 10B, the destination information included in the RTS 21 does not correspond to the device itself, so the transmission standby state (NAV) 50 according to the standby period information included in the Duration 212 of the RTS 21. It becomes.

  On the other hand, the wireless communication device 10D that has received the RTS 21 from the wireless communication device 10B returns a CTS 22 to the wireless communication device 10B. Thereafter, transmission / reception of the data 23 and the ACK 27 between the wireless communication devices 10B and 10D is continued.

  Thereafter, when data 23 addressed to the wireless communication device 10A is transmitted from the wireless communication device 10C, the data 23 can be received by the wireless communication devices 10A and 10E located within the radio wave reachable range 12C.

  Here, when receiving the data 23 addressed to itself, the wireless communication device 10A that is waiting for transmission transmits to the wireless communication device 10C a response signal in which a value that cannot be handled as a transmission permission period is set in the standby period information.

  Further, the wireless communication device 10E that has received the data 23 not addressed to itself from the wireless communication device 10C enters the transmission standby state (NAV) 50 according to the standby period information included in the Duration / ID 234 of the data 23.

  Then, the wireless communication device 10C that has received the response signal transmitted from the wireless communication device 10A stops the subsequent transmission of the data 23 because the response signal indicates that the wireless communication device 10A is waiting for transmission. . Further, the wireless communication device 10C transmits a transmission standby release signal (CF-End) 30 to surrounding devices.

  The wireless communication device 10E that has received the transmission standby release signal 30 from the wireless communication device 10C determines that it is no longer necessary to wait for transmission for the wireless communication device 10C, and cancels the transmission standby state (NAV) 50. As a result, the wireless communication device 10E can perform new communication.

  So far, the flow of communication processing performed between the wireless communication devices 10 in the wireless communication system 1 according to the embodiment has been described. Next, transmission source information / destination information registration processing that can be implemented in the wireless communication device 10 will be described.

[3-5] Registration of transmission source information / destination information In the TXOP function introduced in the standard specification of IEEE802.11, the transmission permission period acquired within the same access priority (AC: Access Class) range It is also permitted to change the address of the communication during. In order to cope with such a change of destination, it is preferable to implement a transmission source information / destination information registration process described below.

  The registration process of transmission source information / destination information is realized mainly using the control unit 144, the data processing unit 148, and the storage unit 152 shown in FIG.

  FIG. 11 is an explanatory diagram illustrating an example of a flow of communication processing performed between the wireless communication devices 10A, 10B, and 10D. In FIG. 11, the wireless communication device 10B serves as a start station, and the wireless communication devices 10A and 10D serve as response stations. The positional relationship between the wireless communication devices 10A, 10B, and 10D in FIG. 11 is the same as the positional relationship illustrated in FIG.

  In the example of FIG. 11, first, the wireless communication device 10B transmits an RTS 21 whose destination is the wireless communication device 10D. The RTS 21 transmitted from the wireless communication device 10B is received by the wireless communication devices 10D and 10A located within the radio wave reachable range 12B.

  When the wireless communication device 10A receives the RTS 21 transmitted from the wireless communication device 10B, the destination information included in the RTS 21 does not correspond to the device itself, so the transmission standby state (NAV) 50 according to the standby period information included in the Duration 212 of the RTS 21. It becomes.

  At this time, the data processing unit 148 of the wireless communication device 10A stores either or both of the transmission source information and the destination information acquired from the communication request signal by the reception data analysis unit 132 in the storage unit 152 as registration station information. Let The registered station information may be, for example, the MAC address of the device included in the source information or the destination information. Further, an arbitrary index number may be assigned to each MAC address for management, and an index number corresponding to transmission source information or destination information may be used as registration station information.

  Data 23 and ACK 27 are transmitted and received between the wireless communication devices 10B and 10D. In the example of FIG. 11, data 23D is transmitted from the wireless communication device 10B to the wireless communication device 10D, and ACK 27D is returned from the wireless communication device 10D to the wireless communication device 10B.

  Thereafter, the communication destination is changed by the wireless communication device 10B during the transmission permission period, and the data 23A addressed to the wireless communication device 10A is transmitted from the wireless communication device 10B. The data 23A is regarded as a communication request signal from the wireless communication device 10B to the wireless communication device 10A.

  The wireless communication device 10A that has received the data 23A first determines in the control unit 144 whether or not the destination of the data 23A is its own device. If the destination of the data 23A is its own device, it is further determined whether or not the transmission source information or the destination information included in the data 23A matches the above-described registered station information stored in the storage unit 152.

  Then, as a result of the determination, the wireless communication device 10A causes the transmission unit 126 to transmit a normal response signal when the transmission source information or the destination information included in the data 23A matches the registration station information. On the other hand, when the transmission source information or the destination information included in the data 23A does not match the registration station information, the transmission unit 126 is caused to transmit a response signal indicating that the own apparatus is waiting for transmission.

  In the example of FIG. 11, the destination of the data 23A is the wireless communication device 10A, and the transmission source is the wireless communication device 10B. Since the registration stations registered when the radio communication device 10A receives the RTS 21 are the radio communication devices 10B and 10D, the transmission source information of the data 23A matches the registration station information. As a result, the normal ACK 27A is returned from the wireless communication device 10A waiting for transmission to the wireless communication device 10B.

  Next, FIG. 12 is an explanatory diagram illustrating another example of the flow of communication processing performed between the wireless communication devices 10A, 10B, and 10D. Also in FIG. 12, the wireless communication device 10B serves as a start station, and the wireless communication devices 10A and 10D serve as response stations. Note that the positional relationship between the wireless communication devices 10A, 10B, and 10D in FIG. 12 is different from the positional relationship illustrated in FIG. 1, and the wireless communication devices 10A, 10B, and 10D are located within a range where they can communicate with each other. .

  In the example of FIG. 12, first, the wireless communication device 10B transmits an RTS 21 destined for the wireless communication device 10D. The RTS 21 transmitted from the wireless communication device 10B is received by the wireless communication device 10D. On the other hand, it is assumed that the radio communication device 10A does not receive the RTS 21 because the radio wave is weak or temporarily outside the radio wave reachable range 12D.

  Thereafter, the CTS 22 is transmitted from the wireless communication device 10D to the wireless communication device 10B. The wireless communication device 10A that has received the CTS 22 from the wireless communication device 10D enters the transmission standby state (NAV) 50 according to the standby period information included in the Duration 224 of the CTS 22 because the destination information included in the CTS 22 does not correspond to the own device.

  At this time, since the transmission source information is not included in the CTS 22, the data processing unit 148 of the wireless communication device 10A stores only the destination information acquired from the CTS 22 by the reception data analysis unit 132 in the storage unit 152 as registered station information. Let In the example of FIG. 12, the MAC address or index number of the wireless communication device 10B is registered in the storage unit 152 of the wireless communication device 10A.

  Thereafter, the data 23D is transmitted from the wireless communication device 10B to the wireless communication device 10D, and an ACK 27D is returned from the wireless communication device 10D to the wireless communication device 10B.

  Then, the communication destination is changed by the wireless communication device 10B during the transmission permission period, and the data 23A addressed to the wireless communication device 10A is transmitted from the wireless communication device 10B. The data 23A is regarded as a communication request signal from the wireless communication device 10B to the wireless communication device 10A.

  The wireless communication device 10A that has received the data 23A first determines in the control unit 144 whether or not the destination of the data 23A is its own device. If the destination of the data 23A is its own device, it is further determined whether or not the transmission source information or the destination information included in the data 23A matches the above-described registered station information stored in the storage unit 152.

  In the example of FIG. 12, the destination of the data 23A is the wireless communication device 10A, and the transmission source is the wireless communication device 10B. Since the registration station registered when the wireless communication device 10A receives the CTS 22 is the wireless communication device 10B, the transmission source information of the data 23A matches the registration station information. As a result, a normal ACK 27A is returned from the wireless communication device 10A waiting for transmission to the wireless communication device 10B.

  By such registration processing of transmission source information / destination information by the wireless communication device 10, when the communication destination is changed during the transmission permission period, it is possible to immediately cope with a new communication.

  Next, communication processing according to an embodiment including the registration processing described in this section will be described with reference to a flowchart described from the viewpoint of a response station.

  FIG. 13 is a flowchart illustrating an example of a flow of communication processing as a response station by the wireless communication device 10 according to an embodiment. Hereinafter, the wireless communication device 10B will be described as a start station, and the wireless communication device 10D will be described as a response station that executes the processing according to this flowchart.

  Referring to FIG. 13, first, a signal transmitted from the wireless communication device 10B to the other wireless communication device 10 is received by the wireless communication device 10D (S502). At this time, in the wireless communication device 10D, based on the destination information of the signal acquired by the reception data analysis unit 132, the control unit 144 determines whether the received signal is addressed to the own device.

  If the received signal is not addressed to the own apparatus, the control unit 144 sets the transmission standby state (NAV) 50 of the transmission unit 126 according to the standby period information included in the signal (S504). Further, the destination information and the transmission source information included in the received signal are registered in the storage unit 152 by the data processing unit 148 (S506).

  Next, the control unit 144 counts down the standby period (S508). Then, the timing when the remaining standby period becomes zero is monitored (S510), and the transmission standby state 50 is canceled when the remaining standby period becomes zero (S512).

  On the other hand, if the remaining standby period is not zero, reception of a signal is awaited in the transmission standby state 50 (S514). When a new signal is received, the control unit 144 determines whether the received signal is addressed to the own device by the control unit 144 (S516).

  If the received signal is not addressed to the own apparatus, it is determined whether the standby period information included in the received signal indicates a period longer than the remaining standby period at that time (S518). If the standby period information is longer than the remaining standby period at that time, the transmission standby state 50 is set by the control unit 144 again according to the new standby period information (S504). On the other hand, when the waiting period information included in the newly received signal is shorter than the remaining waiting period at that time, the waiting period is continuously counted down (S508).

  If the newly received signal is destined for the own apparatus in S516, the control unit 144 determines whether the signal is a communication request signal (S520). The communication request signal here corresponds to, for example, the RTS 21, data 23, or BAR 29 shown in FIG. 3.

  If the signal newly addressed to the device received in S520 is a communication request signal, the control unit 144 causes the transmission source information or destination information included in the communication request signal and the registration station information registered in S506. Are determined to match (S522).

  If the registration station information matches, the wireless communication device 10B, which is the start station, determines that the communication destination has been changed to its own device (that is, the wireless communication device 10D). A signal is transmitted (S524). On the other hand, if the registration station information does not match, a response signal indicating that transmission is on standby is transmitted from the transmission unit 126 in order not to interfere with communication by other wireless communication devices 10 (S526).

  Thereafter, the processing of the wireless communication device 10D returns to S508 and is repeated until the remaining standby period becomes zero.

[4] Summary So far, the wireless communication system 1 according to an embodiment of the present invention and the wireless communication device 10 constituting the wireless communication system 1 have been described in detail with reference to FIGS. In the present embodiment, when the wireless communication device 10 that is waiting for transmission receives a communication request signal addressed to itself, a response signal indicating that the device is waiting for transmission is transmitted from the wireless communication device 10. Is done. As a result, the start station that has transmitted the communication request signal recognizes that the destination wireless communication apparatus is waiting for transmission, and stops the subsequent communication. According to such a configuration, it is possible to reduce the possibility that a communication collision will occur due to the influence of a hidden terminal under the situation where preferential communication is performed by another wireless communication device 10.

  Here, the wireless communication device 10 may set the waiting period information included in the response signal to zero in order to indicate that the device itself is waiting for transmission. Thereby, when the standby period information included in the frame received immediately before by the wireless communication apparatus 10 is used as the transmission permission period, subsequent communication can be stopped without requiring additional processing. Further, the wireless communication device 10 may set a value that cannot be recognized as a transmission permission period in the standby period information in order to indicate that the own apparatus is in a transmission standby state.

  Further, when the response signal indicates that the destination wireless communication apparatus 10 is waiting for transmission, the wireless communication apparatus 10 as the start station may transmit a transmission standby release signal. Thereby, when the destination wireless communication device 10 is waiting for transmission and communication cannot be continued, it is possible to avoid waiting the surrounding wireless communication devices 10 in vain.

  Further, when there is a possibility that the communication destination may be changed during the transmission permission period, the transmission source information or the destination information included in the communication request signal may be stored as registration station information. When receiving a communication request signal addressed to its own device while waiting for transmission, if the transmission source information or destination information included in the communication request signal matches the registered station information stored in advance, the own device transmits A normal response signal may be returned instead of a response signal indicating that the apparatus is waiting. Thereby, it is possible to continue communication with the start station.

  Here, the wireless communication device 10 may use a MAC address corresponding to the transmission source information or the destination information as registration station information stored in the device itself. In this case, since the source or destination MAC address is included in a signal in accordance with a standard specification of general communication, registration station information can be acquired without modifying the format of an existing signal. Further, the wireless communication device 10 may use an index number corresponding to the transmission source information or the destination information as the registration station information stored in the own device. In that case, the storage capacity can be saved.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to the example which concerns. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

  For example, the communication process according to the embodiment described with reference to FIG. 13 does not necessarily have to be executed in the order described in the flowchart. Each processing step may include processing executed in parallel or individually independently.

It is explanatory drawing which shows the structure of the radio | wireless communications system which concerns on one Embodiment. It is explanatory drawing which shows an example of the communication according to a RTS / CTS system. It is explanatory drawing which illustrates the format of the signal transmitted / received with the radio | wireless communications system which concerns on one Embodiment. It is explanatory drawing which shows an example of the communication using a TXOP function. It is explanatory drawing which shows an example of the communication using a NAV function. It is explanatory drawing for demonstrating the subject of the radio | wireless communications system relevant to this invention. It is a block diagram which shows the hardware constitutions of the radio | wireless communication apparatus which concerns on one Embodiment. It is a block diagram which shows the logical structure of the radio | wireless communication apparatus which concerns on one Embodiment. It is explanatory drawing which shows an example of the flow of the communication processing which concerns on one Embodiment. It is explanatory drawing which shows the other example of the flow of the communication processing which concerns on one Embodiment. It is explanatory drawing which shows another example of the flow of the communication processing which concerns on one Embodiment. It is explanatory drawing which shows another example of the flow of the communication processing which concerns on one Embodiment. It is the flowchart which described the flow of the communication processing which concerns on one Embodiment from the viewpoint of the response station.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wireless communication system 10A-10E Wireless communication apparatus 126 Transmission part 134 Reception part 144 Control part 148 Data processing part 152 Memory | storage part

Claims (12)

A transmission unit that transmits a communication request signal including transmission source information for identifying a transmission source wireless communication device or destination information for identifying a transmission destination wireless communication device, and predetermined waiting period information;
A receiving unit for receiving a response signal to the communication request signal;
In addition, when the response signal received by the receiving unit indicates that the destination wireless communication device of the communication request signal is waiting to be transmitted, the subsequent communication with the destination wireless communication device is performed. Control unit to stop communication of
A first wireless communication device comprising:
A receiving unit that receives the communication request signal transmitted from the first wireless communication device;
A transmission unit for transmitting a response signal to the communication request signal;
In addition, when the reception unit receives a communication request signal that is not addressed to its own device, the transmission unit waits for signal transmission over a period indicated by the standby period information included in the communication request signal, and the reception unit A control unit that causes the transmission unit to transmit a response signal indicating that the own device is waiting for transmission when the transmission unit is waiting for transmission when the communication request signal addressed to the own device is received;
A second wireless communication device comprising:
A wireless communication system including: The response signal includes waiting period information,
The control unit of the second wireless communication device sets the waiting period information of the response signal indicating that the device is waiting for transmission to zero.
The wireless communication system according to claim 1. The response signal includes waiting period information,
The control unit of the second wireless communication apparatus sets the standby period information of the response signal indicating that the own apparatus is waiting for transmission to a value that is not recognized as a value indicating the standby period.
The wireless communication system according to claim 1. The control unit of the first wireless communication device transmits when the response signal received by the receiving unit indicates that the wireless communication device that is the destination of the communication request signal is waiting for transmission. Causing the transmission unit to transmit a standby release signal;
The wireless communication system according to claim 1. The second wireless communication device is:
A data processing unit that stores transmission source information or destination information included in the communication request signal received by the reception unit in a storage medium as registration station information;
In addition:
The control unit of the second wireless communication device includes a transmission source included in the communication request signal when the transmission unit is waiting for transmission when the reception unit receives a communication request signal addressed to the second wireless communication device. Only when the information or the destination information does not match the registered station information stored in the storage medium, causes the transmission unit to transmit a response signal indicating that the own apparatus is waiting for transmission.
The wireless communication system according to claim 1.   The wireless communication system according to claim 5, wherein the control unit of the second wireless communication apparatus uses a MAC address corresponding to the transmission source information or the destination information as the registration station information.   The wireless communication system according to claim 5, wherein the control unit of the second wireless communication apparatus uses an index number corresponding to the transmission source information or the destination information as the registration station information. A transmission unit for transmitting a communication request signal including transmission source information for identifying a transmission source wireless communication device or destination information for identifying a transmission destination wireless communication device, and predetermined waiting period information;
A receiving unit for receiving a response signal to the communication request signal;
If the response signal received by the receiving unit indicates that the wireless communication device that is the destination of the communication request signal is waiting to be transmitted, subsequent communication with the wireless communication device that is the destination A control unit for stopping
A wireless communication device comprising: A communication request signal transmitted from another wireless communication device, including transmission source information for identifying the wireless communication device of the transmission source or destination information for identifying the wireless communication device of the destination and predetermined waiting period information A receiver for receiving the signal;
A transmission unit for transmitting a response signal to the communication request signal;
When the reception unit receives a communication request signal that is not addressed to its own device, the transmission unit waits for transmission of a signal over a period indicated by the standby period information included in the communication request signal, and the reception unit A control unit that causes the transmission unit to transmit a response signal indicating that the own device is waiting for transmission when the transmission unit is waiting for transmission when a communication request signal addressed to the device is received;
A wireless communication device comprising: Transmitting from the first wireless communication device a communication request signal including transmission source information for identifying the wireless communication device of the transmission source, destination information for identifying the wireless communication device of the destination, and predetermined waiting period information;
Receiving a communication request signal transmitted from the first wireless communication device in a second wireless communication device;
In the second wireless communication apparatus, when the received communication request signal is not addressed to the own apparatus, waiting for signal transmission over a period indicated by the waiting period information included in the communication request signal;
In the second wireless communication device, when the received communication request signal is addressed to the own device and the own device is waiting for transmission, a response signal indicating that the own device is waiting for transmission; ;
Receiving a response signal to the transmitted communication request signal in the first wireless communication device;
In the first wireless communication device, when the received response signal indicates that the wireless communication device that is the destination of the communication request signal is waiting for transmission, the communication with the wireless communication device that is the destination Stopping subsequent communications;
A wireless communication method. A computer that controls the wireless communication device:
A transmission unit for transmitting a communication request signal including transmission source information for identifying a transmission source wireless communication device or destination information for identifying a transmission destination wireless communication device, and predetermined waiting period information;
A receiving unit for receiving a response signal to the communication request signal;
If the response signal received by the receiving unit indicates that the wireless communication device that is the destination of the communication request signal is waiting to be transmitted, subsequent communication with the wireless communication device that is the destination A control unit for stopping
Program to function as A computer that controls the wireless communication device:
A communication request signal transmitted from another wireless communication device, including transmission source information for identifying the wireless communication device of the transmission source or destination information for identifying the wireless communication device of the destination and predetermined waiting period information A receiver for receiving the signal;
A transmission unit for transmitting a response signal to the communication request signal;
When the reception unit receives a communication request signal that is not addressed to its own device, the transmission unit waits for transmission of a signal over a period indicated by the standby period information included in the communication request signal, and the reception unit A control unit that causes the transmission unit to transmit a response signal indicating that the own device is waiting for transmission when the transmission unit is waiting for transmission when a communication request signal addressed to the device is received;
Program to function as

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