JP2009055246A - Wireless communication apparatus, wireless communication method, program, and wireless communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wireless communication apparatus, a wireless communication method, a program, and a wireless communication system. <P>SOLUTION: The wireless communication apparatus 10 which receives a transmission request signal from another wireless communication apparatus, transmits a response signal, corresponding to the transmission request signal, to another wireless communication apparatus, and then receives a data signal from another wireless communication apparatus, includes: a time zone setting part for setting a plurality of request time zones for receiving the transmission request signal, and a plurality of response time zones to be arranged, after the plurality of request time zones, in order to transmit the response signal; a communication part for communicating with the circumferential wireless communication apparatus; and a response control part for controlling whether to control transmission of the response signal from the communication part in the plurality of response time zones, according to the reception state of the transmission request signal from the circumferential wireless communication apparatus in the plurality of request time zones. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

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

  In wireless communication systems, for example, an access control method based on the RTS / CTS method is used. In the RTS / CTS scheme, a transmitting-side wireless communication apparatus transmits an RTS to a receiving-side wireless communication apparatus, a receiving-side wireless communication apparatus transmits a CTS in response to the RTS, and a transmitting-side wireless communication apparatus This is a method for starting data transmission upon reception of CTS from a receiving-side wireless communication apparatus. According to the RTS / CTS method, a so-called hidden terminal that is not directly detected by the transmitting-side wireless communication apparatus but is known by the receiving-side wireless communication apparatus is transmitted simultaneously with the transmitting-side wireless communication apparatus. The case of transmitting can be suppressed.

  A wireless communication system using the RTS / CTS method is described in Patent Document 1, for example. The wireless communication system is intended to prevent simultaneous transmission of RTS by a hidden terminal and transmission of CTS by a reception-side wireless communication device. For this reason, in the wireless communication system, the difference in frame interval between the wireless communication device with the higher priority and the wireless communication device with the lower priority is set to be equal to or longer than the time required from the RTS transmission to the CTS reception.

  In the RTS / CTS system, when a peripheral terminal station communicates with a central control station in a wireless communication system having a star-type network and borology, the signal of the peripheral terminal station specified by the central control station is reliably received. It is used to make it. That is, the RTS / CTS method is a method suitable for many-to-one communication control in which there are many transmission sources and one reception destination.

  In recent years, a UWB wireless communication system in a high-speed personal area network using an ultra wide band (UWB) has been proposed. In the UWB wireless communication system, a method of performing communication in an autonomous and distributed manner with wireless communication apparatuses existing in the vicinity has been proposed. The rules for performing communication by autonomous distributed control are described in, for example, the Distributed Media Access Control Layer specification formulated by WiMedia Alliance.

JP 2006-41627 A

  However, when the wireless communication system described in Patent Document 1 is applied to an autonomously distributed UWB wireless communication system, there is a problem in that RTS transmissions by a plurality of wireless communication apparatuses having the same signal transmission priority cannot be detected. there were. For example, when a plurality of wireless communication devices transmit RTS at the same time, only one of the RTSs is decoded by the receiving wireless communication device, and it is difficult to detect an RTS collision due to a mismatch in the frame check sequence. It was. As a result, there is a case where the receiving-side wireless communication apparatus inappropriately transmits a response signal such as CTS regardless of whether or not a collision of transmission request signals such as RTS has actually occurred.

  Accordingly, the present invention has been made in view of the above problems, and an object of the present invention is to provide a plurality of request time zones for transmitting a transmission request signal and response time zones for transmitting a response signal. It is an object of the present invention to provide a new and improved wireless communication apparatus, wireless communication method, program, and wireless communication system capable of realizing smoother communication control.

  In order to solve the above-described problem, according to an aspect of the present invention, after receiving a transmission request signal from another wireless communication apparatus and transmitting a response signal to the transmission request signal to the other wireless communication apparatus, A wireless communication device in which a data signal is transmitted from another wireless communication device, wherein a plurality of request time zones for receiving the transmission request signal and a plurality of request time zones for transmitting the response signal A plurality of response time zones to be arranged later, a time zone setting unit for setting, a communication unit for communicating with surrounding wireless communication devices, and the transmission request from the surrounding wireless communication devices in the plurality of request time zones There is provided a wireless communication apparatus comprising: a response control unit that controls whether or not the response signal can be transmitted from the communication unit in the plurality of response time periods according to a signal reception state.

  In such a configuration, since a plurality of request time zones are set, the communication unit can receive transmission request signals addressed to itself or other devices from a plurality of wireless communication devices in different request time zones. Here, assuming that only a single request time zone is provided, the communication unit may normally receive only one transmission request signal even if transmission request signals are transmitted from a plurality of wireless communication devices. In contrast, the wireless communication apparatus can normally receive the transmission request signal from the plurality of wireless communication apparatuses in different time zones as described above. As a result, it is possible for the response control unit to determine whether or not the response signal can be transmitted according to the reception status of the transmission request signal by the communication unit in a plurality of request time periods, thereby realizing smoother communication control.

  When the communication unit receives a transmission request signal addressed to its own device in any of the plurality of request time zones and does not receive a transmission request signal addressed to another device, the response control unit is configured to You may make the said communication part transmit the response signal with respect to the transmission request signal addressed to the said own apparatus in any time slot | zone. If the communication unit receives a transmission request signal addressed to its own device in any of a plurality of request time zones and does not receive a transmission request signal addressed to another device, the transmission of the data signal to the own device is considered not to collide. It is done. Therefore, in this case, the response control unit causes the communication unit to transmit a response signal to the transmission request signal addressed to the own device in any of a plurality of response time zones, thereby transmitting the transmission request signal addressed to the own device Communication can be continued and throughput can be improved.

  When the communication unit receives a transmission request signal addressed to its own device in any of the plurality of request time zones and receives a transmission request signal addressed to another device, the response control unit The response signal may not be transmitted to the communication unit in a response time zone. When the communication unit receives a transmission request signal addressed to its own device in any of a plurality of request time zones and receives a transmission request signal addressed to another device, data signals transmitted from a plurality of wireless communication devices Are considered to collide with each other. Therefore, in this case, the response control unit can prevent data signals from colliding by not transmitting response signals in a plurality of response time zones.

  The communication unit receives a transmission request signal addressed to the own device in any of the plurality of request time zones, receives a transmission request signal addressed to another device, and based on the transmission request signal addressed to the other device If a data signal corresponding to the transmission request signal addressed to the other apparatus is not received after the transmission start timing of the data signal corresponding to the estimated transmission request signal addressed to the other apparatus, the transmission request signal addressed to the own apparatus The wireless communication apparatus may further include a delay response control unit that causes the communication unit to transmit a delay response signal that responds with a delay to the communication unit. When the data signal corresponding to the transmission request signal addressed to the other device is not received after the transmission start timing of the data signal corresponding to the transmission request signal addressed to the other device estimated based on the transmission request signal addressed to the other device, It is considered that data signals addressed to other devices are not transmitted. In this case, since it is considered that data signals transmitted from a plurality of wireless communication devices do not collide with each other, it is inefficient that the own device does not communicate with the transmission source device of the transmission request signal addressed to the own device. . Therefore, in this case, the delay response control unit causes the communication unit to transmit a delayed response signal that responds with a delay to the transmission request signal addressed to the own device, and continues communication with the transmission source device of the transmission request signal addressed to the own device. Thus, throughput can be improved.

  The wireless communication device includes an estimation unit that estimates a transmission end position of a data signal transmitted by surrounding wireless communication devices, and a confirmation signal for the data signal transmitted from the other wireless communication device to the communication unit. And a confirmation control unit that causes the communication unit to transmit after the transmission end position of the data signal transmitted by the surrounding wireless communication devices. In such a configuration, it is possible to prevent the confirmation signal transmitted from the own apparatus and the data signal transmitted from the surrounding wireless communication apparatuses from colliding with each other in the other wireless communication apparatuses.

  The communication unit receives a transmission request signal addressed to itself from another wireless communication device in any of the plurality of request time zones, and receives a response signal addressed to another device in any of the plurality of response time zones. In this case, the response control unit may not transmit the response signal from the communication unit to the other wireless communication device in the plurality of response time zones. Further, the wireless communication device includes an estimation unit that estimates a transmission end position of a data signal corresponding to the response signal addressed to the other device, and a data signal corresponding to the response signal addressed to the other device estimated by the estimation unit. And a delay response control unit that transmits a delay response signal that responds with a delay to the transmission request signal from the communication unit to the other wireless communication device after the transmission end position.

  In order to solve the above problem, according to another aspect of the present invention, a transmission request signal is transmitted to another wireless communication device, and a response signal to the transmission request signal is received from the other wireless communication device. A wireless communication apparatus that starts transmission of a data signal later, and is arranged after a plurality of request time periods for transmitting the transmission request signal and the plurality of request time periods for receiving the response signal A time zone setting unit for setting a plurality of response time zones, a time zone selection unit for selecting one of the request time zones, and a request time zone selected by the time zone selection unit A communication unit that transmits the transmission request signal to the other wireless communication device, and the data from the communication unit according to a reception status of the response signal from the other wireless communication device in the plurality of response time zones. Signal transmission A transmission control section that controls whether the wireless communication apparatus comprising a are provided.

  In such a configuration, since a plurality of request time zones are set, the communication unit can transmit a transmission request signal in the request time zone selected by the selection unit. Also, since a plurality of response time zones are set, the communication unit can receive response signals addressed to the own device or response signals addressed to other devices transmitted from a plurality of wireless communication devices in different response time zones. . As a result, the transmission control unit can determine whether or not the data signal can be transmitted in accordance with the reception status of the response signal by the communication unit in a plurality of response time zones, thereby realizing smoother communication control.

  The communication unit does not receive the response signal from the other wireless communication device in the plurality of response time zones, and the other wireless communication device responds with a delay to the transmission request signal within a predetermined period. When the delay response signal is received, the transmission control unit may cause the communication unit to transmit the data signal after the delay response signal is received. Here, the fact that the communication unit has received the delay response signal from the other wireless communication device is considered that the other wireless communication device is ready to receive the data signal. Therefore, in this case, the transmission control unit causes the communication unit to start transmitting a data signal, thereby improving the throughput of wireless communication.

  The communication unit does not receive the response signal from the other wireless communication device in the plurality of response time zones, and the other wireless communication device responds with a delay to the transmission request signal within a predetermined period. When the delayed response signal to be received is not received, the communication unit may transmit the transmission request signal again in the request time zone selected by the selection unit. Here, when neither the response signal nor the delayed response signal is received even though the transmission request signal is transmitted from the communication unit to the other wireless communication device, the transmission request signal is not received by the other wireless communication device. there is a possibility. Therefore, in this case, the communication unit can communicate with another wireless communication device by transmitting the transmission request signal again. Also, compared to resending the transmission request signal when the response signal is not received, the number of transmissions of the transmission request signal can be suppressed, thereby preventing unnecessary transmission opportunities of surrounding wireless communication devices from being reduced. it can.

  When the communication unit receives a data signal not addressed to the own device, the transmission control unit receives the data signal from the communication unit in a time zone in which a confirmation signal for the data signal not addressed to the own device is transmitted. May be stopped. According to this configuration, it is possible to prevent a case in which a confirmation signal for a data signal not destined for the own apparatus collides with a data signal transmitted from the own apparatus in the transmission source apparatus of the data signal not addressed to the own apparatus.

  When the communication unit receives a response signal addressed to another device in any of the plurality of response time zones, the transmission control unit may not cause the communication unit to transmit the data signal.

  In order to solve the above problem, according to another aspect of the present invention, a transmission request signal is received from another wireless communication device, and a response signal to the transmission request signal is transmitted to the other wireless communication device. A wireless communication method executed later in a wireless communication apparatus to which a data signal is transmitted from the other wireless communication apparatus, wherein a plurality of request time zones for receiving the transmission request signal and the response signal are transmitted A plurality of response time zones arranged after the plurality of request time zones, and a reception status of the transmission request signal from the surrounding wireless communication devices in the plurality of request time zones. Accordingly, there is provided a wireless communication method including the step of controlling whether or not to transmit the response signal in the plurality of response time zones.

  In order to solve the above problem, according to another aspect of the present invention, a transmission request signal is transmitted to another wireless communication device, and a response signal to the transmission request signal is received from the other wireless communication device. A wireless communication method executed in a wireless communication device that starts transmission of a data signal later, wherein a plurality of request time zones for transmitting the transmission request signal and the plurality of requests for receiving the response signal A step of setting a plurality of response time zones arranged after the time zone, a step of selecting one of the plurality of request time zones, and a request time selected by the time zone selection unit Transmitting the transmission request signal to the other wireless communication device in a band, and receiving the data signal according to a reception status of the response signal from the other wireless communication device in the plurality of response time zones. And controlling the availability of the transmission, the radio communication method comprising is provided.

  In order to solve the above-described problem, according to another aspect of the present invention, a computer receives a transmission request signal from another wireless communication device, and sends a response signal to the transmission request signal as the other wireless communication device. A wireless communication device to which a data signal is transmitted from the other wireless communication device after transmitting to the plurality of request time zones for receiving the transmission request signal and the transmission signal to transmit the response signal A time zone setting unit for setting a plurality of response time zones arranged after a plurality of request time zones, a communication unit for communicating with a surrounding wireless communication device, and the surrounding wireless communications in the plurality of requested time zones A response control unit that controls whether or not the response signal can be transmitted from the communication unit in the plurality of response time zones according to the reception status of the transmission request signal from the device. Because of the program is provided.

  Such a program can cause the hardware resources of a computer including, for example, a CPU, a ROM, or a RAM to execute the functions of the time zone setting unit, the communication unit, and the response control unit as described above. That is, a computer using the program can function as the above-described wireless communication device.

  In order to solve the above problems, according to another aspect of the present invention, a computer transmits a transmission request signal to another wireless communication device, and a response signal to the transmission request signal from the other wireless communication device. Is a wireless communication device that starts transmission of a data signal after receiving a plurality of request time periods for transmitting the transmission request signal and after the plurality of request time periods for receiving the response signal A plurality of response time zones arranged, a time zone setting unit for setting, a time zone selection unit for selecting one of the plurality of request time zones, and a time zone selection unit A communication unit that transmits the transmission request signal to the other wireless communication device in a request time zone, and a reception status of the response signal from the other wireless communication device in the plurality of response time zones. Of the above Program for functioning as a radio communication apparatus and a transmission control unit for controlling the propriety of transmission of the data signal is provided.

  Such a program can cause the hardware resources of a computer including, for example, a CPU, ROM, or RAM to execute the functions of the time zone setting unit, the time zone selection unit, the communication unit, and the transmission control unit as described above. That is, a computer using the program can function as the above-described wireless communication device.

  In order to solve the above problem, according to another aspect of the present invention, a wireless communication system including a first wireless communication device and a second wireless communication device is provided. The first wireless communication apparatus includes a plurality of request time zones for transmitting a transmission request signal and a plurality of time zones arranged after the plurality of request time zones for receiving a response signal in response to the transmission request signal. A response time zone, a time zone setting unit for setting, a time zone selection unit for selecting one of the plurality of request time zones, and a request time zone selected by the time zone selection unit A communication unit that transmits the transmission request signal to the other wireless communication device. In addition, the second wireless communication device may receive the first response signal in the plurality of response time zones according to a reception status of the transmission request signal from a surrounding wireless communication device in the plurality of request time zones. A response control unit that controls whether or not transmission to the wireless communication apparatus is possible is provided. In addition, the first wireless communication device transmits the data signal to the second wireless communication device according to the reception status of the response signal from the second wireless communication device in the plurality of response time zones. Control whether or not.

  As described above, according to the wireless communication device, the wireless communication method, the program, and the wireless communication system according to the present invention, the request time zone for transmitting the transmission request signal and the response time zone for transmitting the response signal are set. By providing a plurality, smoother communication control can be realized.

  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.

Further, the “best mode for carrying out the invention” will be described in the order shown below.
[1] Outline of wireless communication system according to this embodiment [2] Various frame configurations [3] Purpose of this embodiment [4] Configuration of wireless communication apparatus according to this embodiment [5] Wireless communication according to this embodiment Operation of the device [6] Summary

[1] Overview of Radio Communication System According to this Embodiment First, the configuration of the radio communication system 1 according to this embodiment will be described with reference to FIG. 1 and FIG.

  FIG. 1 is an explanatory diagram showing a configuration of a wireless communication system 1 according to the present embodiment. The wireless communication system 1 includes wireless communication devices 10A to 10G. Each of the wireless communication devices 10A to 10G can communicate in an autonomous and distributed manner (form a wireless network) with the wireless communication device included in each of the radio wave reachable ranges 12A to 12G.

  Specifically, the wireless communication device 10A can communicate with the wireless communication devices 10B, 10C, and 10G included in the radio wave reachable range 12A. The wireless communication device 10B can communicate with the wireless communication device 10A included in the radio wave reachable range 12B. The wireless communication device 10C can communicate with the wireless communication devices 10A and 10F included in the radio wave reachable range 12C.

  Similarly, the wireless communication device 10D can communicate with the wireless communication devices 10E, 10F, and 10G included in the radio wave reachable range 12D. The wireless communication device 10E can communicate with the wireless communication device 10D included in the radio wave reachable range 12E. The wireless communication device 10F can communicate with the wireless communication devices 10C and 10D included in the radio wave reachable range 12F. Furthermore, the wireless communication device 10G can communicate with the wireless communication devices 10A and 10D included in the radio wave reachable range 12G.

  In the present specification, the radio communication devices 10A to 10G are simply referred to as a radio communication device 10 unless it is necessary to distinguish between them. The wireless communication device 10 includes, for example, a PC (Personal Computer), a home video processing device (DVD recorder, VCR, etc.), a mobile phone, a PHS (Personal Handyphone System), a portable music playback device, and a portable video processing device. It may be an information processing apparatus such as a PDA (Personal Digital Assistant), a home game machine, a portable game machine, or a home appliance. The wireless communication system 1 may be a wireless USB system or a wireless LAN (Local Area Network).

  FIG. 2 is an explanatory diagram showing a configuration example of a superframe. The super frame period is defined by a predetermined time (for example, 65 ms), and is subdivided into 256 media access slots (MAS). The wireless communication devices 10 constituting the wireless communication system 1 share the super frame period as a frame of a predetermined period, and transfer of messages is performed in units of the above-described fragmented MAS.

  Furthermore, at the head of the super frame, there is a beacon period (BP) as a management area for transmitting and receiving management information by a beacon (beacon signal), and a beacon slot (BS) is arranged at a predetermined interval. Yes. In addition, a unique beacon slot is set for each wireless communication device 10, and parameters for network management and access control are exchanged with surrounding wireless communication devices 10. FIG. 2 shows an example in which nine beacon slots BS0 to BS8 are set as the beacon period. The period that is not set as the beacon period is normally used as a data transmission area.

In the wireless communication system 1, each wireless communication device 10 can perform DRP reservation (DRP: Distributed Reservation Protocol) in units of MAS shown in FIG. Such DRP reservation types include:
(1) AlienBP
(2) Hard DRP
(3) Soft DRP
(4) Private DRP
(5) PCA (Priority Contention Access)
and so on.

  In the MAS reserved by the DRP reservation whose reservation type is AlienBP, each wireless communication device 10 constituting the wireless communication system 1 does not perform any signal transmission. Further, in a MAS reserved by DRP reservation whose reservation type is hard DRP, only the wireless communication device 10 that is the reservation source and the reservation destination of the DRP reservation can perform wireless communication.

  On the other hand, contention communication is performed in a MAS reserved by DRP reservation whose reservation type is soft DRP or PCA. For example, the wireless communication device 10A that wants to transmit data to the wireless communication device 10B uses RTS (Request To Send) as a transmission request signal in the MAS reserved by the DRP reservation whose reservation type is soft DRP or PCA. Send to. Then, the wireless communication device 10B that has received the RTS transmits a CTS (Clear To Send) as a response signal to the wireless communication device 10A.

  Further, the wireless communication device 10A that has received the CTS from the wireless communication device 10B determines that the device has the right to transmit data and starts transmitting data. When the wireless communication device 10B has successfully received data from the wireless communication device 10A, the wireless communication device 10B transmits an ACK (AckKnowledgement) to the wireless communication device 10A as a confirmation signal, and a series of wireless communication ends.

  Hereinafter, a frame configuration example such as RTS / CTS and a frame configuration example such as a beacon for performing DRP reservation will be described.

[2] Various frame configurations (PHY frame)
FIG. 3 is an explanatory diagram showing a configuration example of a PHY frame. As illustrated in FIG. 3, the PHY frame includes a preamble 601, a PHY header 602, a MAC header 603, an HCS 604, and an RSParity (Reed-Solomon Parity) 605. The preamble 601 is a known pattern signal used for each wireless communication device 10 to synchronize during reception processing, and is transmitted over 9.375 μs.

  The PHY header 602 includes information indicating characteristics such as a transfer rate and a modulation method of the frame, and has a data length of 5 bytes. The MAC header 603 includes management information such as the address of the wireless communication device 10 that is the transmission source or the destination of the frame, and the data length is 10 bytes. The HCS 604 has a function of detecting an error, the data length is 2 bytes, and the RSParity 601 has a data length of 6 bytes. Therefore, in consideration of Tail Bits, when the transfer rate is 53.3 Mbps, the PHY header 602 It takes 3.75 μs to receive from RSParity 605.

(Beacon frame)
FIG. 4 is an explanatory diagram showing a configuration example of a beacon frame. As illustrated in FIG. 4, the beacon frame includes a physical layer header (PH) 610, a beacon header (Beacon Header), an HCS 616, a beacon payload, and an FCS 620.

  The beacon header includes frame control information (Frame Control) 611, destination address (DestAddr) 612, transmission source address (SrcAddr) 613, sequence control information (Sequence Control) 614, and access control information (Access Control) 615.

  The beacon payload includes information element-N (IE-N) 619 from beacon specific information (Beacon Parameter) 617 and information element-1 (IE-1) 618.

(DRP reservation information element)
FIG. 5 is an explanatory diagram showing a configuration example of a DRP reservation information element that is an information element included in a beacon. As shown in FIG. 5, the DRP reservation information element includes an element ID (Element ID) 621 indicating the type of the information element, an information length (Length) 622 of the information element, and a DRP control indicating the reservation type of the DRP reservation. Information (DRP Control) 623, address (Target / Owner DevAddr) 624 for identifying a wireless communication apparatus to be reserved, information 1 indicating a group of slots for which DRP reservation is performed (DRP Allocation 1) 625, and N (DRP) Allocation N) 626.

(PCA usage notification information element)
FIG. 6 is an explanatory diagram showing a configuration example of a PCA usage notification information element that is an information element included in a beacon. As shown in FIG. 6, the PCA usage notification information element includes an element ID (Element ID) 631 that indicates the type of the information element, an information length (Length) 632 of the information element, and information that clearly indicates the meaning of the element ( (Interpretation) 633 and information (PCA Availability Bitmap) 634 specifying the slot position used for PCA.

  FIG. 7 is an explanatory diagram showing another configuration example of the PCA usage notification information element which is an information element included in the beacon. As shown in FIG. 7, the PCA usage notification information element indicates an element ID (Element ID) 641 indicating the type of the information element, an information length (Length) 642 of the information element, and a communication partner in the PCA. Address 1 (DevAddr 1) 643 to address N (DevAddr N): 644.

(RTS frame)
FIG. 8 is an explanatory diagram showing a configuration example of the RTS frame. As illustrated in FIG. 8, the RTS frame includes a physical layer header (PH) 710, an RTS header (RTS Header), and a header check sequence (HCS) 716.

  The RTS header includes frame control information (Frame Control) 711, a destination address (DestAddr) 712, a transmission source address (SrcAddr) 713, sequence control information (Sequence Control) 714, and access control information (Access Control) 715.

  Of the access control information 715, the duration information (Duration) field 717 describes the time corresponding to the transmission end position of the data to be transmitted. In the duration information field 717, the time until the CTS return time corresponding to the RTS may be described.

  In addition, the access control information 715 includes a bit (ACK Req. Frames) 718 indicating whether or not there is an ACK return request. Depending on the bit 718 indicating the presence or absence of the ACK return request, it is possible to determine whether or not the wireless communication device 10 that has received data thereafter transmits an ACK.

(CTS frame)
FIG. 9 is an explanatory diagram showing a configuration example of a CTS frame. As shown in FIG. 9, the CTS frame includes a physical layer header (PH) 720, a CTS header (CTS Header), and a header check sequence (HCS) 726. The CTS header includes frame control information (Frame Control) 721, destination address (DestAddr) 722, transmission source address (SrcAddr) 723, sequence control information (Sequence Control) 724, and access control information (Access Control) 725.

  In the access control information 725, the duration information (Duration) field 727 describes a time corresponding to the reception end position of the data to be received. Further, the access control information 725 includes a bit (ACK Req. Frames) 728 indicating whether or not an ACK can be returned. The CTS transmission source device can describe in the bit 728 indicating whether or not ACK can be returned after the end of subsequent data transmission.

(Cross-to-send frame)
FIG. 10 is an explanatory diagram showing a configuration example of a cross-to-send (XTS) frame. The cross-to-send frame has a function as a delayed response signal transmitted when responding with a delay to the RTS. As shown in FIG. 10, the cross-to-send frame includes a physical layer header (PH) 730, a cross-to-send header (XTS Header), and a header check sequence (HCS) 736.

  The cross-to-send header includes frame control information (Frame Control) 731, destination address (DestAddr) 732, transmission source address (SrcAddr) 733, sequence control information (Sequence Control) 734, and access control information (Access Control) 735. Including.

  In the access control information 735, the duration information (Duration) field 737 describes a time corresponding to the reception end position of the data to be received. Furthermore, the access control information 735 includes a bit (ACK Req. Frames) 738 indicating whether or not an ACK can be returned. The XTS transmission source device can describe in the bit 728 whether or not the ACK can be returned after the subsequent data transmission is completed.

(Data frame)
FIG. 11 is an explanatory diagram showing a configuration example of a data frame. As shown in FIG. 11, the data frame includes a physical layer header (PH) 740, a data header (Date Header), a header check sequence (HCS) 746, and a payload (Data Payload) 747 of the actually transmitted data. And a frame check sequence (FCS) 748.

  The data header includes frame control information (Frame Control) 741, destination address (DestAddr) 742, transmission source address (SrcAddr) 743, sequence control information (Sequence Control) 744, and access control information (Access Control) 745.

(ACK frame)
FIG. 12 is an explanatory diagram showing a configuration example of an ACK (immediate ack) frame. As shown in FIG. 12, the ACK frame includes a physical layer header (PH) 750, an ACK header (Immediate ACK Header), and a header check sequence (HCS) 756.

  The ACK header includes frame control information (Frame Control) 751, destination address (DestAddr) 752, transmission source address (SrcAddr) 753, sequence control information (Sequence Control) 754, and access control information (Access Control) 755.

(Block ACK frame)
FIG. 13 is an explanatory diagram showing a configuration example of a block ACK frame. The block ACK is a signal for transmitting a data reception result to the communication partner when the communication partner requests transmission of ACK (when receiving Block ACK Request).

  As illustrated in FIG. 13, the block ACK frame includes a physical layer header (PH) 760, a block ACK header (Block ACK Header), a header check sequence (HCS) 766, and ACK information of normally received data. A payload (ACK Payload) 767 and a frame check sequence (FCS) 768 are included.

[3] Purpose of this embodiment The outline of the wireless communication system 1 according to this embodiment and various frame configurations transmitted and received in the wireless communication system 1 have been described above. Subsequently, the object of the present embodiment will be described with reference to FIGS. 14 to 18 by taking the wireless communication device 14 related to the present embodiment as a comparative example.

  FIG. 14 is an explanatory diagram showing a state of communication control by the wireless communication device 14 related to the present embodiment. More specifically, FIG. 14 shows an exposed terminal problem in which when an RTS or CTS is transmitted from a certain wireless communication device 14, all transmissions by surrounding wireless communication devices are hindered.

  Further, each wireless communication device 14 shown in FIG. 14 can communicate only with the upper and lower wireless communication devices unless otherwise specified. The same applies to FIGS.

  As shown in FIG. 14, when the wireless communication device 14B transmits the RTS 30a, the wireless communication device 14C transmits the CTS 32a in response to the RTS 30a. When the wireless communication device 14B receives the CTS 32a, the wireless communication device 14B transmits data 34a. When the wireless communication device 14C normally receives the data 34a, the wireless communication device 14B transmits ACK 36a.

  On the other hand, the wireless communication device 14A that has received the RTS 30a sets the NAV (transmission standby state) 38a until the transmission of the ACK 36a is completed, and the wireless communication device 14D that has received the CTS 32a sets the NAV 38b until the transmission of the ACK 36a is completed.

  Actually, it is not necessary for the wireless communication device 14A to set the NAV 30a in order to eliminate signal collision in the wireless communication device 14C. That is, if the wireless communication device 14A did not receive the CTS 32a, it should have been allowed to transmit a signal. However, in the conventional RTS / CTS system, there is a so-called exposed terminal that misses the transmission opportunity even though it is not necessary to set the NAV 30a unlike the wireless communication device 14A.

  In the example shown in FIG. 14, since the wireless communication device 14D sets the NAV 38b, the CTS 32 cannot be returned even when the RTS 30b is received from the wireless communication device 14E. As a result, the RTS 30c is retransmitted by the wireless communication device 14E, the transmission path is unnecessarily maintained, and the throughput of the remote wireless communication device may decrease.

  FIG. 15 is an explanatory diagram showing another state of communication control by the wireless communication device 14 related to the present embodiment. More specifically, FIG. 15 shows a problem when the RTS 30 is transmitted from the plurality of wireless communication devices 14 in response.

  As shown in FIG. 15, when the wireless communication device 14B transmits the RTS 30e, the wireless communication device 14A transmits the CTS 32e in response to the RTS 30e. When the wireless communication device 14B receives the CTS 32e, the wireless communication device 14B transmits data 34e, and when the wireless communication device 14A normally receives the data 34e, the wireless communication device 14B transmits ACK 36e.

  On the other hand, when the RTS 30f is transmitted by the wireless communication device 14D simultaneously with the RTS 30e, the RTS 30e and the RTS 30f collide with each other in the wireless communication device 14C existing at a position where both RTSs can be decoded. In this case, the radio communication device 14C cannot decode both of the RTS 30e and the RTS 30f, or decodes the higher one of the signal levels.

  As a result, since the wireless communication device 14C does not transmit the CTS 32f in response to the RTS 30f, the wireless communication device 14D transmits the RTS 30g. However, since the RTS 30g collides with the data 34e in the wireless communication device 14C, the CTS 32g is not transmitted from the wireless communication device 14C. Thereafter, when the wireless communication device 14D transmits the RTS 30h after the transmission of the data 34e is completed, the wireless communication device 14C can transmit the CTS 32h.

  When the transmission of the RTS 30 is repeated by the wireless communication device 14D in this way, the transmission opportunity of the farther wireless communication device 14 is deprived. Specifically, there is a problem that the wireless communication device 14E sets the NAV 38f until the communication of the wireless communication device 14D ends, and communication cannot be performed.

  FIG. 16 is an explanatory diagram showing another state of communication control by the wireless communication device 14 related to the present embodiment. More specifically, FIG. 16 shows the problem when the CTS 32 collides.

  As shown in FIG. 16, when the wireless communication device 14A transmits the RTS 30i, the wireless communication device 14B transmits the CTS 32i in response to the RTS 30i. When the wireless communication device 14A receives the CTS 32i, the wireless communication device 14A transmits data 34i, and when the wireless communication device 14B normally receives the data 34i, the wireless communication device 14B transmits ACK 36i.

  On the other hand, when the wireless communication device 14D transmits the RTS 30j at substantially the same timing as the RTS 30i, the wireless communication device 14C transmits the CTS 32j in response to the RTS 30j at substantially the same timing as the CTS 32i. When the wireless communication device 14D receives the CTS 32j, the wireless communication device 14D transmits data 34j.

  However, since the data 34j collides with the ACK 36i transmitted by the wireless communication device 14B in the wireless communication device 14C, the wireless communication device 14C cannot normally receive the data 34j. Then, since the wireless communication device 14D does not receive the ACK 36j from the wireless communication device 14C, the wireless communication device 14D transmits the RTS 30k again to retransmit the data.

As a result, the remote wireless communication device 14E sets the NAV 38 that cannot perform communication over a time more than twice the time required for the original data transmission by the wireless communication device 14D. As a method of solving such a problem, a scenario in which ACK return is not intentionally performed is also conceivable, but a new problem arises that a reception buffer must be formed over the time until ACK is returned, It has not reached a realistic solution.

  FIG. 17 is an explanatory diagram showing another state of communication control by the wireless communication device 14 related to the present embodiment. More specifically, FIG. 17 shows a problem that a frame that should originally be transmitted preferentially is delayed due to a difference in recognition of the previous communication end position.

  FIG. 17 shows a state in which RTS 30l is transmitted prior to RTS 30m from wireless communication device 14D that cannot inherently transmit priority when wireless communication device 14B has the right to transmit RTS 30m with priority. In this case, the wireless communication device 14C that has received the RTS 301 sets the NAV 30l.

  As a result, even if the wireless communication device 14C receives the RTS 30m from the wireless communication device 14B, the wireless communication device 14C cannot return the CTS before the ACK 36l is transmitted from the wireless communication device 14E. The wireless communication device 14B that has transmitted the RTS 30m retransmits the RTS 30n because the CTS is not transmitted from the wireless communication device 14C, but the CTS is not returned from the wireless communication device 14C. That is, the wireless communication device 14B has a problem that it occupies a transmission path even though data communication is not performed.

  Furthermore, there is a risk that signal transmission by the wireless communication device 14A receiving the RTSs 30m, 30n, and 30o transmitted by the wireless communication device 14B may be suppressed, and there is a concern that the throughput of the entire system may deteriorate. Thus, it can be seen that setting the reference timing is indispensable when priority control is applied to a communication protocol with high random accessibility.

  Further, as shown in FIG. 18, the wireless communication system described in Patent Document 1 determines the difference in frame interval between the wireless communication device with the higher priority and the wireless communication device with the lower priority from the transmission of the RTS to the CTS. More than the time required to receive

  FIG. 18 is an explanatory diagram showing a slot arrangement in a conventional wireless communication system. As shown in FIG. 18, RTS slots 30A and 32A are arranged as priority 1 slots, and RTS slots 30B and 32B are arranged as priority 2 slots following priority 1 slots. Yes. Similarly, RTS slots 30C and 32C are arranged as priority 3 slots following priority 2 slots, and RTS slots 30D and 32D are arranged as priority 4 slots following priority 3 slots. ing.

  According to such a conventional wireless communication system, it is possible to prevent simultaneous transmission of RTS by the hidden terminal and transmission of CTS by the reception-side wireless communication apparatus.

  However, the conventional wireless communication system cannot cope with the collision between RTS and CTS transmitted from wireless communication devices having the same priority. For example, the wireless communication devices 14A and 14C having the same priority 1 may both transmit RTS in the RTS slot 30A and cause a collision in the wireless communication device 14B.

  Further, as described above, when the conventional access control method based on the RTS / CTS method is adopted, there is a problem that throughput is lowered due to a so-called “exposed terminal problem”. That is, since the wireless communication apparatus 14 that has received the RTS frame has suppressed transmission even when it does not receive the CTS frame, the transmission is suppressed and the throughput is reduced even though data transmission was originally possible. There was a problem of lowering.

  This should be controlled so that the wireless communication device 14 that originally exists around the receiving-side wireless communication device 14 that transmitted the CTS does not interfere with the data reception. On the other hand, if the CTS from the receiving wireless communication device 14 is not received around the transmitting wireless communication device 14 that has transmitted the RTS, the transmission can be performed.

  In addition, as an access control method using UWB, since carrier detection is difficult, a redundant preamble signal is added to each frame and transmitted, so that it takes time to acquire an access right. . Furthermore, according to the method of detecting a redundant preamble using a maximum likelihood code decoding process (Viterbi decoding process), if there are multiple different signals at the same time, only a signal with good characteristics is decoded with a slight difference. Therefore, there is a problem that it is difficult to realize a scenario for detecting a collision due to a mismatch of the frame check sequences.

  That is, in a wireless communication system using UWB, it is difficult to apply a conventional carrier sense multiple access type protocol, and the conventional access control method cannot be followed. As a result, in a wireless communication system using UWB, there is a background that random access control cannot be performed, which is adopted in an IEEE802.11 wireless LAN or the like.

  Therefore, when the conventional RTS / CTS control method is applied to a wireless communication system having a mesh network topology, in addition to the wireless communication device on the transmission side and the wireless communication device on the reception side, It was necessary to grasp the trend and perform access control. That is, there is a demand for a many-to-many communication control method in which there are a large number of transmission sources and a plurality of reception destinations. There is a problem that a collision occurs in a plurality of radio communication apparatuses on the receiving side only by the conventional access control by exchanging RTS / CTS. Accordingly, access control for determining whether or not reception is possible is also required by a plurality of radio communication apparatuses on the receiving side, and it is necessary to perform many-to-many communication control.

  Accordingly, the wireless communication device 10 according to the present embodiment has been created with the above circumstances taken into consideration. The wireless communication apparatus 10 according to the present embodiment can realize smoother communication control by providing a plurality of request slots for transmitting RTS and a plurality of response slots for transmitting CTS. Hereinafter, the wireless communication device 10 will be described in detail with reference to FIGS. 19 to 34.

[4] Configuration of Wireless Communication Device According to this Embodiment FIG. 19 is a functional block diagram showing the configuration of the wireless communication device 10 according to this embodiment. As illustrated in FIG. 19, the wireless communication device 10 includes an antenna 101, a reception processing unit 102, a reception frame analysis unit 103, a reception beacon processing unit 116, a PCA usage notification analysis unit 117, and a DRP reservation management unit. 118, a reception MAS setting unit 119, an available MAS management unit 120, a reception data buffer 121, an interface 122, a transmission data buffer 123, a reservation necessity determination unit 124, a PCA usage notification setting unit 125, A transmission MAS setting unit 126, a transmission beacon setting unit 127, a timing management unit 128, a communication control unit 130, a data length analysis unit 142, a transmission frame setting unit 144, and a transmission processing unit 145 are provided.

  The antenna 101 receives a signal transmitted from another wireless communication apparatus and transmits a signal generated by the transmission processing unit 145. The reception processing unit 102 detects a preamble from the signal received by the antenna 101 and decodes a signal following the preamble. That is, the antenna 101 and the reception processing unit 102 cooperate to bear a part of the function as the communication unit.

  The reception frame analysis unit 103 extracts header information and data payload from the signal decoded by the reception processing unit 102. The reception beacon processing unit 116 analyzes the beacon frame extracted by the reception frame analysis unit 103. The PCA usage notification analysis unit 117 determines whether the beacon includes PCA usage notification information and whether the PCA usage notification information relates to its own device.

  The DRP reservation management unit 118 stores the DRP reservation status. When the DRP reservation information element is included in the beacon, the stored reservation status is updated according to the DRP reservation information element. The reception MAS setting unit 119 receives the MAS determined by the PCA usage notification analysis unit 117 that the beacon including the PCA usage notification information related to the own device has been received, and the MAS that the own device needs to perform reception processing based on the DRP reservation. Set as MAS.

  The available MAS management unit 120 extracts an available MAS based on the DRP reservation status stored in the DRP reservation management unit 118. The reception data buffer 121 stores a data frame addressed to its own device. The interface 122 transmits and receives data between the wireless communication device 10 and an application device (not shown). The transmission data buffer 123 stores data received from the application device via the interface 122. Further, the reservation necessity determination unit 124 determines the necessity of DRP reservation from the frequency of data to be transmitted, the required communication quality, latency, and the like.

  When the reservation necessity determination unit 124 determines that the DRP reservation is not necessary, the PCA usage notification setting unit 125 grasps the available MAS extracted by the available MAS management unit 120, and the wireless communication apparatus of the communication partner PCA usage notification is set for.

  The transmission MAS setting unit 126 sets the MAS set by the PCA usage notification setting unit 125 as the transmission MAS. If the DRP reservation is determined to be necessary by the reservation necessity determination unit 124, the DRP reservation management unit 118 sets the DRP reservation among the available MASs extracted by the available MAS management unit 120. The transmission MAS setting unit 126 sets the MAS corresponding to the DRP reservation determined by the DRP reservation management unit 118 as the transmission MAS.

  The transmission beacon setting unit 127 generates a beacon frame including beacon information elements such as the DRP reservation information element and the PCA usage notification information element. The transmission frame setting unit 144 generates each transmission frame such as RTS, CTS, data, ACK, and block ACK based on the control of the communication control unit 130 and the timing management unit 128.

  The transmission processing unit 145 adds a predetermined preamble to the transmission frame generated by the transmission frame setting unit 144 and modulates the transmission frame. The signal (frame) modulated by the transmission processing unit 145 is transmitted from the antenna 101, and the transmission processing unit 145 and the antenna 101 cooperate with each other to function as a communication unit.

  The timing management unit 128 determines the arrival timing of the reception MAS set by the reception MAS setting unit 119 and the transmission MAS set by the transmission MAS setting unit 126, the communication control unit 130, the reception frame analysis unit 103, and the transmission frame setting unit 144. Notify. In addition, the timing management unit 128 includes a plurality of request slots QS for transmitting RTS, response slots RS for transmitting CTS, and start slots SS for starting data transmission in the reception MAS and the transmission MAS, respectively. Configure, deploy and manage.

  20 to 22 are explanatory diagrams showing examples of slot arrangement by the timing management unit 128. FIG.

  As shown in FIG. 20, the first request slot QS0 is allocated after the SIFT interval has elapsed from the MAS start timing, and then the request slot QS1 is allocated. Following the request slot QS1, response slots RS0 and RS1 are arranged, followed by start slots SS0 and SS1.

  When receiving the RTS in any of the request slots QS, the wireless communication device 10 transmits the CTS in the response slot RS corresponding to the slot received in the request slot. For example, when the wireless communication device 10 receives RTS addressed to itself in the request slot QS0, the wireless communication device 10 transmits CTS in the response slot RS0.

  Further, the wireless communication device 10 starts data transmission in the start slot SS corresponding to the request slot QS that transmitted the RTS. For example, when the radio communication apparatus 10 transmits RTS in the request slot QS1 and receives CTS in the response slot RS1, data transmission is started in the start slot SS1. The timing management unit 128 may notify the communication control unit 130 of the start of each request slot QS, response slot RS, and start slot SS1.

  In FIG. 20, the case where two slots are arranged has been described. However, three slots may be arranged as shown in FIG. 21, or four slots may be arranged as shown in FIG. Good.

  For example, as shown in FIG. 21, the first request slot QS0 may be allocated after the SIFT interval has elapsed from the MAS start timing, and then the request slots QS1 and QS2 may be allocated. Further, response slots RS0, RS1, and RS2 may be arranged following request slot QS2, and start slots SS0, SS1, and SS2 may be arranged thereafter.

  When receiving the RTS in any of the request slots QS, the wireless communication device 10 transmits the CTS in the response slot RS corresponding to the slot received in the request slot. For example, when the wireless communication device 10 receives RTS addressed to itself in the request slot QS2, the wireless communication device 10 transmits CTS in the response slot RS2.

  Further, the wireless communication device 10 starts data transmission in the start slot SS corresponding to the request slot QS that transmitted the RTS. For example, when the radio communication apparatus 10 transmits RTS in the request slot QS2 and receives CTS in the response slot RS2, data transmission is started in the start slot SS2.

  Similarly, as shown in FIG. 22, the first request slot QS0 may be allocated after the SIFT interval has elapsed from the MAS start timing, and then the request slots QS1, QS2, and QS3 may be allocated. Further, response slots RS0, RS1, RS2, and RS3 may be arranged following request slot QS3, and start slots SS0, SS1, SS ″, and SS3 may be arranged thereafter.

  When receiving the RTS in any of the request slots QS, the wireless communication device 10 transmits the CTS in the response slot RS corresponding to the slot received in the request slot. For example, when the wireless communication device 10 receives RTS addressed to itself in the request slot QS3, the wireless communication device 10 transmits CTS in the response slot RS3.

  Further, the wireless communication device 10 starts data transmission in the start slot SS corresponding to the request slot QS that transmitted the RTS. For example, when the wireless communication apparatus 10 transmits RTS in the request slot QS3 and receives CTS in the response slot RS3, data transmission is started in the start slot SS3.

  As shown in FIGS. 20 to 22, by arranging a plurality of request slots QS and response slots RS, even if RTS or CTS is transmitted from a plurality of wireless communication devices 10 at the same time, different request slots QS, A collision can be detected if the response slot RS is used.

  Here, returning to the description of the configuration of the wireless communication apparatus 10 according to the present embodiment with reference to FIG. 19, the communication control unit 130 includes an RTS transmission control unit 132, a data transmission control unit 134, and a CTS response control unit. 136, an XTS response control unit 138, and an ACK response control unit 140.

  The RTS transmission control unit 132 has a function as a time zone selection unit that selects one of the request slots QS arranged by the timing management unit 128 when transmitting the RTS in the MAS in which the use of PCA is set. The transmission processing unit 145 transmits the RTS in the request slot QS selected by the RTS transmission control unit 132.

  The RTS transmission control unit 132 may transmit the RTS again when neither the CTS nor the XTS is received within a predetermined period after transmitting the RTS. Here, when neither the CTS nor the XTS is received even though the RTS is transmitted to another wireless communication device, there is a possibility that the RTS is not received by the other wireless communication device. Therefore, in this case, communication with another wireless communication device can be performed by transmitting the RTS. In addition, since the number of RTS transmissions can be suppressed as compared with the case where the RTS is retransmitted when the CTS is not received, it is possible to prevent the transmission opportunities of the surrounding wireless communication apparatuses from being unnecessarily reduced.

  The CTS response control unit 136 functions as a response control unit that controls transmission of the CTS in the response slot RS according to the reception status of the RTS in the request slot QS. For example, when the RTS addressed to the own device is received in any of the plurality of request slots QS and the RTS addressed to the other device is not received, the transmission of the data signal to the own device is considered not to collide. Therefore, in this case, the CTS response control unit 136 may perform control so that the CTS for the RTS addressed to the own apparatus is transmitted in any of the plurality of response slots RS. As a result, it is possible to continue communication with the RTS transmission source device addressed to the device itself and improve the throughput.

  Further, when an RTS addressed to the own device is received in any of the plurality of request slots QS and an RTS addressed to another device is received, it is considered that data transmitted from the plurality of wireless communication devices collide with the own device. It is done. Therefore, in this case, the CTS response control unit 136 can prevent data collision by performing control so that CTS transmission is not performed in a plurality of response slots RS.

  The data transmission control unit 134 functions as a transmission control unit that controls the start of data transmission in the start slot SS in accordance with the CTS reception status in the plurality of request slots QS. For example, the data transmission control unit 134 may perform control so that data transmission is not started in a plurality of request slots QS when a CTS addressed to another device is received in any of the plurality of request slots QS.

  In addition, when the wireless communication device 10 receives data that is not addressed to the own device, the data transmission control unit 134 causes the transmission of the data signal to be stopped in the slot where the ACK for the data that is not addressed to the own device is transmitted. You may control to. The slot in which ACK for data not destined for the own apparatus will be transmitted can be estimated by the data length analysis unit 142 based on, for example, duration information (Duration) included in the header of the data not destined for the own apparatus. That is, the data length analysis unit 142 has a function as an estimation unit that estimates the transmission end position of data and the transmission position of ACK. According to such a configuration, it is possible to prevent a case where an ACK for data not addressed to the own apparatus collides with data transmitted from the own apparatus in a transmission source apparatus of data not addressed to the own apparatus.

  In addition, when data that is not addressed to the own device is received in the start slot SS, the data transmission control unit 134 stops data transmission from the own device in a time zone in which an ACK for data that is not addressed to the own device will be transmitted. You may control so that it is. According to such a configuration, it is possible to prevent a case where an ACK for data not addressed to the own apparatus collides with data transmitted from the own apparatus in a transmission source apparatus of data not addressed to the own apparatus.

  The ACK response control unit 140 functions as a confirmation control unit that performs control so that ACK is transmitted when data is normally received from the communication partner. Further, the ACK response control unit 140 does not need to transmit an ACK when the bit 718 indicating the presence or absence of an ACK return request for the corresponding RTS frame indicates that the ACK return is unnecessary.

  The XTS response control unit 138 is a delay response control unit that controls transmission of an XTS that responds with a delay to the RTS according to the reception status of the RTS in the plurality of request slots QS and the reception status of the CTS in the plurality of response slots RS. Function.

  For example, when an RTS addressed to the own apparatus is received from another wireless communication apparatus in any of the plurality of request slots QS and a CTS addressed to the other apparatus is received in any of the plurality of response slots SS, the CTS response control unit 136 May be controlled so that CTS is not transmitted to the other wireless communication devices in a plurality of response slots SS. At this time, the XTS response control unit 138 may perform control so that an XTS responding with a delay to the RTS is transmitted after the transmission end position of the data corresponding to the CTS addressed to the other device.

  In addition, the RTS addressed to the own device is received in any of the plurality of request slots QS, the RTS addressed to the other device is received, and the RTS addressed to the other device estimated based on the RTS addressed to the other device. If the data corresponding to the RTS addressed to the other device is not received in the corresponding data transmission start slot SS, the XTS response control unit 138 communicates the XTS that responds with a delay to the RTS addressed to the own device. You may control to.

  If data corresponding to the RTS addressed to the other device is not received after the transmission start slot SS of the data corresponding to the RTS addressed to the other device estimated based on the RTS addressed to the other device, Data is considered not transmitted. In this case, since it is considered that data transmitted from a plurality of wireless communication devices 10 does not collide with the own device, it is inefficient that the own device does not communicate with the RTS transmission source device addressed to the own device. Therefore, in this case, the XTS response control unit 138 performs control so that an XTS that responds with delay to the RTS addressed to the own device is transmitted, and communication with the transmission source device of the RTS addressed to the own device is continued. Can be improved.

  A specific example of communication control by the communication control unit 130 described above will be described with reference to FIGS. Each wireless communication device 10 shown in FIGS. 23 to 31 can communicate only with the upper and lower wireless communication devices unless otherwise specified.

  FIG. 23 is an explanatory diagram showing an example of communication control according to the present embodiment. As shown in FIG. 23, first, the wireless communication device 10B transmits the RTS 20a addressed to the wireless communication device 10A in the request slot QS0. Further, the wireless communication device 10C transmits the RTS 20b addressed to the wireless communication device 10D in the request slot QS1.

  Here, the wireless communication device 10A does not receive the RTS 20b transmitted from the wireless communication device 10C, and the wireless communication device 10D does not receive the RTS 20a transmitted from the wireless communication device 10B. In this case, it is considered that the data 24a and 24b transmitted from the wireless communication devices 10B and 10C do not collide with each other in the wireless communication device 10A and the wireless communication device 10D.

  Therefore, the wireless communication device 10A transmits the CTS 22a in the response slot RS0 based on the control of the CTS response control unit 136, and the wireless communication device 10D transmits the CTS 22b in the response slot RS1 based on the control of the CTS response control unit 136. The wireless communication devices B and 10C are caused to transmit data 24a and 24b.

  However, if ACK is returned at the end of data as before, the ACK may collide with other data. Therefore, in the present embodiment, it is possible to realize smooth communication by not transmitting ACK based on the control by the ACK response control unit 140 when the communication ends first among the wireless communication device 10A and the wireless communication device 10D. It is said. Note that both the wireless communication device 10A and the wireless communication device 10D may be configured not to transmit ACK. In this way, the exposed terminal problem in the radio communication system 1 using the RTS / CTS scheme can be solved.

  FIG. 24 is an explanatory diagram showing another example of communication control according to the present embodiment. As shown in FIG. 24, first, the wireless communication device 10B transmits the RTS 20c addressed to the wireless communication device 10A in the request slot QS0. Further, the wireless communication device 10C transmits the RTS 20d addressed to the wireless communication device 10D in the request slot QS1.

  Here, the wireless communication device 10A does not receive the RTS 20d transmitted from the wireless communication device 10C, and the wireless communication device 10D does not receive the RTS 20c transmitted from the wireless communication device 10B. In this case, it is considered that the data 24c and 24d transmitted from the wireless communication devices 10B and 10C do not collide with each other in the wireless communication device 10A and the wireless communication device 10D.

  Accordingly, the wireless communication device 10A transmits CTS 22c in the response slot RS0, the wireless communication device 10D transmits CTS 22d in the response slot RS1, and causes the wireless communication devices B and 10C to transmit data 24c and 24d.

  However, if ACK is returned at the end of data as before, the ACK may collide with other data. Therefore, in the present embodiment, at the timing when the wireless communication device 10A transmits the ACK 26c, the wireless communication device 10C stops transmission of the data 24d based on the control by the ACK response control unit 140, thereby preventing signal collision. I am going to do that. Note that the timing at which the wireless communication device 10A transmits the ACK 26c can be estimated based on the duration information 717 included in the RTS 20C by the data length analysis unit 142 of the wireless communication device 10C, for example.

  FIG. 25 is an explanatory diagram showing another example of communication control according to the present embodiment. As shown in FIG. 25, first, the wireless communication device 10C transmits the RTS 20e addressed to the wireless communication device 10D in the request slot QS0. Further, the wireless communication device 10A transmits the RTS 20f addressed to the wireless communication device 10B in the request slot QS1.

  Subsequently, the wireless communication device 10D transmits the CTS 22e addressed to the wireless communication device 10C in the response slot RS0. On the other hand, since the wireless communication device 10B receives the RTS 20f addressed to itself and the RTS 20e addressed to another device in a plurality of request slots, the wireless communication device 10B does not transmit the CTS 22f. Then, after the communication between the wireless communication device 10C and the wireless communication device 10D is completed, the wireless communication device 10B transmits the XTS 29f based on the control of the XTS response control unit 138, and the wireless communication device 10A performs data 24f according to the XTS 29f. Send '.

  In such a configuration, the case where the wireless communication device 10A repeatedly transmits RTS unnecessarily because the CTS is not returned can be suppressed, and the transmission path can be used efficiently. Note that the wireless communication device 10A may retransmit the RTS when the XTS is not received even after the timing at which the ACK is transmitted for the data when the longest data is transmitted from the start slot.

  FIG. 26 is an explanatory diagram showing another example of communication control according to the present embodiment. As shown in FIG. 26, first, the wireless communication device 10A transmits the RTS 20g addressed to the wireless communication device 10B in the request slot QS0. Further, the wireless communication device 10C transmits the RTS 20h addressed to the wireless communication device 10D in the request slot QS1.

  Here, since the wireless communication device 10B receives the RTS 20g addressed to itself and the RTS 20h addressed to another device in the plurality of request slots, the wireless communication device 10B does not transmit the CTS 22g. On the other hand, the wireless communication device 10D transmits the CTS 22h addressed to the wireless communication device 10C in the response slot RS1.

  Then, after the communication between the wireless communication device 10C and the wireless communication device 10D is completed, the wireless communication device 10B transmits the XTS 29g based on the control of the XTS response control unit 138, and the wireless communication device 10A performs data 24g according to the XTS 29g. Send '.

  In such a configuration, the case where the wireless communication device 10A repeatedly transmits RTS unnecessarily because the CTS is not returned can be suppressed, and the transmission path can be used efficiently. Also, as shown in FIG. 26, the wireless communication device 10C that has transmitted the RTS 20h using the request slot QS1 on the slower side can transmit the data 24h first. That is, there is no superiority or inferiority relationship between the request slots QS used for RTS transmission, and fair access control can be realized.

  FIG. 27 is an explanatory diagram showing another example of communication control according to this embodiment. As shown in FIG. 27, first, the wireless communication device 10A transmits the RTS 20i addressed to the wireless communication device 10B in the request slot QS0. At the same time, the wireless communication device 10E transmits the RTS 20j in the request slot QS0. Further, the wireless communication device 10C transmits the RTS 20k addressed to the wireless communication device 10D in the request slot QS1.

  Here, since the wireless communication device 10B receives the RTS 20i addressed to itself and the RTS 20k addressed to another device in a plurality of request slots, the wireless communication device 10B does not transmit the CTS 22i. Similarly, the wireless communication device 10D does not transmit the CTS 22k because it receives the RTS 20k addressed to itself and the RTS 20j addressed to another device in a plurality of request slots. Here, it is assumed that the wireless communication device 10E has not received the CTS addressed to the wireless communication device 10E.

  At this time, since data from any wireless communication device 10 is not transmitted in the start slot SS0, the wireless communication device 10D can detect that the transmission path is empty. Accordingly, the wireless communication device 14D transmits XTS 29k in the start slot SS1 to the wireless communication device 10C that has transmitted RTS 20k, and receives data 24k from the wireless communication device 10C.

  Further, the wireless communication device 10B estimates the communication end positions of the wireless communication device 10C and the wireless communication device 10D based on the data 24k transmitted by the wireless communication device 10C, and transmits the XTS 29i to the wireless communication device 10A after the communication ends. Data 24i ′ can be received.

  In addition, the wireless communication device 10E receives the XTS 29k transmitted from the wireless communication device 10D, grasps that the transmission path is usable after the data reception and the return of the ACK 26k are completed, and performs data transmission as necessary. Can be resumed. As described above, the access control method suitable for the wireless communication system 1 having the mesh type network topology is obtained by returning the necessity of data reception mainly by the reception-side wireless communication device 10.

  FIG. 28 is an explanatory diagram showing another example of communication control according to the present embodiment. As shown in FIG. 28, first, the wireless communication device 10A transmits the RTS 20l addressed to the wireless communication device 10B in the request slot QS0. Further, the wireless communication device 10D transmits the RTS 20m addressed to the wireless communication device 10C in the request slot QS1.

  Subsequently, the wireless communication device 10B transmits CTS 22l addressed to the wireless communication device 10A in the response slot RS0. Then, based on the CTS 22l received in the response slot RS0, the wireless communication device 10C transmits the CTS 22m when there is no ACK return from the wireless communication device 10B and the data length is shorter than the data length of the own device.

  Thus, according to the present embodiment, even when a plurality of wireless communication devices 10 transmit CTS at the same time, the transmission path can be used efficiently.

  FIG. 29 is an explanatory diagram showing another example of communication control according to the present embodiment. As shown in FIG. 29, first, the wireless communication device 10A transmits the RTS 20n addressed to the wireless communication device 10B in the request slot QS0. Further, the wireless communication device 10D transmits the RTS 20o addressed to the wireless communication device 10C in the request slot QS1.

  Subsequently, the wireless communication device 10B transmits CTS 22n addressed to the wireless communication device 10A in the response slot RS0. Then, the wireless communication device 10C grasps the data length of the data 24n that the wireless communication device 10B will communicate based on the CTS 22n received in the response slot RS0. When the data length of the data 24n is longer than the data 24o that the own device will communicate and there is an ACK return request to the own device, the wireless communication device 10D determines the return position of the ACK 26o based on the control of the ACK response control unit 140. The data length is adjusted to 24o. That is, the wireless communication device 10C describes the same received data length in the CTS 22o as the wireless communication device 10B.

  As described above, even when CTSs are transmitted from a plurality of wireless communication devices 10 at the same time, the transmission path can be effectively used by adjusting the ACK return timing.

  FIG. 30 is an explanatory diagram showing another example of communication control according to the present embodiment. As shown in FIG. 30, first, the wireless communication device 10A transmits the RTS 20p addressed to the wireless communication device 10B in the request slot QS0. Further, the wireless communication device 10D transmits the RTS 20q addressed to the wireless communication device 10C in the request slot QS1.

  Subsequently, the wireless communication device 10B transmits the CTS 22p addressed to the wireless communication device 10A in the response slot RS0. In addition, the wireless communication device 10C that has received RTSq in the request slot QS1 determines whether or not it is necessary to return the CTS 22q using the data length parameter described in the CTS 22p transmitted by the wireless communication device 10B.

  For example, when the data length described in the CTS 22p is shorter than the received data length of the own device, the wireless communication device 10C returns an ACK, and when the data reception of the own device and a collision occur, After the transmission of the CTS 22q is stopped and the communication of the wireless communication device 10B is completed, the XTS 29q is transmitted to the wireless communication device 10D.

  In this case, the wireless communication device 10C does not transmit the CTS 22q, but returns the XTS 29q after returning the ACK 26p of the adjacent wireless communication device 10B. In this way, the wireless communication device 10C can achieve coexistence between adjacent communication devices by first performing communication with the wireless communication device 10B that is the counterpart.

  FIG. 31 is an explanatory diagram showing another example of communication control according to the present embodiment. As shown in FIG. 31, first, the wireless communication device 10D transmits the RTS 20r addressed to the wireless communication device 10C in the request slot QS0. It is assumed that the RTS 20r is received by the wireless communication device 10B. Further, the wireless communication device 10A transmits the RTS 20s addressed to the wireless communication device 10B in the request slot QS1. It is assumed that the RTS 20s is received by the wireless communication device 10C.

  Then, the wireless communication devices 10B and 10C have not received the CTS 22r and the CTS 22s because they have received RTSs addressed to themselves and other devices in the plurality of request slots RS.

  Thereafter, since transmission of the data 24r from the wireless communication device 10D is not started at the timing of the start slot SS0, the wireless communication device 10B can grasp that the transmission path is empty. Therefore, the wireless communication device 10B transmits XTS 29s to the wireless communication device 10A based on the control by the XTS response control unit 138. Then, the data 24s is transmitted from the wireless communication device 10A to the wireless communication device 10B.

  Since the wireless communication device 10C can grasp that the XTS 29s has been transmitted, the wireless communication device 10C transmits the XTS 29r to the wireless communication device 10D after the transmission of the data 24s. As a result, data 24r 'is transmitted from the wireless communication device 10D to the wireless communication device 10C. In this way, an access control method that compensates for the shortcomings of RTS / CTS control can be obtained by transmitting XTS when the transmission line is idle and effectively operating the past RTS.

[5] Operation of Wireless Communication Device According to Present Embodiment The configuration of the wireless communication device 10 according to the present embodiment has been described above. Subsequently, a wireless communication method executed in the wireless communication apparatus 10 according to the present embodiment will be described with reference to FIGS.

  FIG. 32 is a flowchart showing a flow of a wireless communication method executed in the wireless communication apparatus 10 according to the present embodiment. First, after power is turned on, the wireless communication device 10 scans for a predetermined period, and if there is an existing beacon period, sets a beacon period and a beacon slot to be used according to the existing beacon period, and if there is no beacon period Initial setting for newly setting a beacon period and a beacon slot to be used is performed (S201).

  When the beacon period arrives (S202), the wireless communication device 10 transmits a predetermined beacon at the timing of the beacon slot of the own device (S203) (S204). The wireless communication device 10 performs a beacon reception process except for its own beacon slot. If a beacon is received (S205), the wireless communication device 10 performs a process for the presence or absence of the following information elements.

  That is, if there is a PCA usage notification addressed to itself (S206), the wireless communication device 10 acquires MAS information used for the PCA (S207) and sets reception of the corresponding MAS (S208). Further, when there is a request for DRP reservation addressed to itself (S209), the wireless communication device 10 generates a received DRP reservation response (S211) if the requested MAS is available (S210), A response is returned with the next beacon, and reception of the corresponding MAS is set (S212).

  If the MAS is not available, the wireless communication device 10 generates a response that rejects the DRP reservation (S213), and returns a response with the next beacon. Further, when receiving a non-approval of DRP reservation addressed to the own device (S214), the wireless communication device 10 acquires unused DRP MAS information (S215), designates a new MAS, and transmits a DRP. The reservation request is reset (S216).

  On the other hand, if the wireless communication device 10 receives a DRP reservation response addressed to itself (S217), the wireless communication device 10 sets transmission in the corresponding MAS (S218). On the other hand, if there is a DRP reservation response addressed to another device (S219), the wireless communication device 10 registers the corresponding MAS as a currently used MAS (S220).

  Further, when the interface 122 receives transmission data outside the beacon period (S221), the wireless communication device 10 buffers the data in the transmission data buffer 123 (S222). Further, the wireless communication device 10 determines whether or not reserved transmission is necessary from the transmission quality and latency request of the data, and if reserved transmission is unnecessary (S223), obtains usable MAS information (S224). .

  Further, the wireless communication device 10 transmits a MAS that has not been reserved for DRP in the surrounding wireless communication devices by using PCA with the minimum necessary MAS among the MASs that can be used by the device itself. Is set as (S225). Subsequently, the wireless communication device 10 sets transmission in the MAS (S226), further generates a notification of PCA usage to the receiving wireless communication device (S227), and sends it with the next beacon.

  On the other hand, if the reserved transmission is necessary, the wireless communication apparatus 10 obtains usable MAS information (S228), and among the unused MASs, the necessary MAS is set as the DRP utilization MAS according to a predetermined policy (S229). ). In addition, the wireless communication device 10 generates a DRP reservation request to the wireless communication device that is the reception destination (S230), and sends it with the next beacon.

  When the MAS for which transmission has been set arrives (S231), the wireless communication device 10 sets the IFS waiting time to the waiting time defined by PCA communication if the MAS is set to transmit PCA (S232). (S233). On the other hand, if DRP transmission is set, the process proceeds to transmission access control according to the present embodiment (S234), and data transmission processing is performed.

  When the MAS for which reception is set arrives (S235), the wireless communication device 10 shifts to reception access control according to the present embodiment (S236), and performs data reception processing. Then, after completing each of these operations, the wireless communication device 10 returns to S202 and continuously operates by repeating a series of operations.

  FIG. 33 is a flowchart showing a flow of transmission access control in the present embodiment. Here, when a MAS for which transmission has been set arrives and the PCA transmission MAS is set, access control is performed after the IFS transmission waiting time elapses. Further, when the transmission DAS is set as the Soft DRP, the access control is performed without setting the transmission waiting time.

  First, if a priority waiting time is set, the wireless communication device 10 sets the waiting time, and the timing management unit 128 arranges the request slot QS, the response slot RS, and the start slot SS (S301). Thereafter, the wireless communication device 10 sets the position of the request slot (QS) for transmission. Here, for example, the wireless communication device 10 mainly sets the use of the request slot QS1 when requesting the return of ACK to the data to be transmitted (S302), and mainly when not requesting the return of ACK. The case where the use of the request slot QS0 is set (S304) is shown. However, the wireless communication apparatus 10 may determine other conditions or a request slot to be used at random.

  When the wireless communication device 10 receives the RTS addressed to the other device (S305), if there is an ACK return request in the data transmission of the own device (S306), the duration information 717 described in the RTS addressed to the other device. (S307), and based on the duration information 717, the duration information in the data of its own device is adjusted (S308). At this time, control may be performed so that an ACK return request is not made in the data transmission of the own device by receiving the RTS addressed to the other device.

  In addition, when the transmission timing of the request slot QS for which transmission is set comes (S309), the wireless communication device 10 transmits an RTS frame (S310). Thereafter, the wireless communication device 10 performs CTS reception processing. When a CTS addressed to another device is received (S311), the duration information 727 of the corresponding data is acquired (S312).

  This process is continued until the wireless communication apparatus 10 receives the CTS addressed to itself (S313) or until the reception timing of the response slot RS is exceeded (S314). On the other hand, when receiving the CTS addressed to the own device (S313), the wireless communication device 10 transmits a data frame (S315). If the own device issues a request for returning an ACK (S316), the wireless communication device 10 transmits the data frame (S316). Receive. If the wireless communication device 10 does not receive an ACK at a predetermined timing (S317), it sets a retransmission flag (S318), moves to S314, and retransmits data.

  If the wireless communication device 10 receives an ACK or does not issue an ACK return request, the wireless communication device 10 refers to the remaining amount of transmission data and ends the data transmission processing if there is no remaining (S319). If there is a remaining data, the process proceeds to S322 and is compared with the remaining time of the transmission MAS. If there is a remaining time, the process proceeds to S314 and the remaining data transmission is continued. If there is no remaining data or if there is no remaining MAS time, the process is terminated.

  Further, if the reception timing of the response slot RS is exceeded and the reception of the XTS addressed to the own device is received (S320), the wireless communication device 10 acquires the duration information 737 of the data addressed to the own device (S321) and transmits it. Compared with the remaining time of the MAS (S322), if there is a remaining time, the process proceeds to S314 and the remaining data transmission is continued. On the other hand, the wireless communication device 10 ends the process if there is no remaining MAS time.

  If the duration information 727 of the data addressed to the other device acquired in S312 is exceeded (S323), it is compared with the remaining time of the transmission MAS (S324). The access control procedure until acquisition is started from the beginning. On the other hand, the wireless communication device 10 ends the process if there is no remaining time for the transmission MAS.

  FIG. 34 is a flowchart showing the flow of reception access control in this embodiment. Here, in the MAS to which reception is set, this reception processing is continuously performed, and when a preset MAS arrives, a series of processing is started and used continuously. The reception process shown in FIG. 34 is performed until the end time of the last MAS for which is set.

  First, the wireless communication device 10 arranges a request slot QS, a response slot RS, and a start slot SS (S400). When the wireless communication device 10 first receives the RTS addressed to the device itself (S401), the wireless communication device 10 acquires and stores the duration information 717 of the data addressed to the device itself (S402). A CTS response slot (RS) that is opposite to the RTS request slot (QS) is set (S403).

  Thereafter, the wireless communication device 10 does not receive the RTS addressed to the other device (S404), and may receive an ACK after receiving the data of the own device, for example, when receiving the CTS addressed to the other device (S405). In this case (S406), the duration information 727 of the data described in the CTS addressed to the other device is acquired (S407).

  If the duration information 727 of the data described in the CTS addressed to the other device is longer than the data length of the data addressed to the own device (S408), the wireless communication device 10 The data length of the device data is matched with the duration information 727 (S409). On the other hand, when there is no reception of the CTS addressed to the other device, the wireless communication device 10 does not perform this adjustment when the own device does not return the ACK. If the CTS addressed to the other device is shorter than the data length of the data addressed to the own device, the process proceeds to S414 to cancel the CTS transmission setting of the own device. In this way, it is determined whether CTS return is necessary, and a CTS frame to be returned is set (S410).

  These determinations are repeated until the timing of the CTS response slot RS arrives, and when the RS timing comes (S411), the CTS frame is actually transmitted (S412).

  When receiving the RTS addressed to the other device before the response slot RS arrives, the wireless communication device 10 starts the transmission of the data addressed to the other device from the timing of the request slot QS of the RTS addressed to the other device. (S413), and the setting of the response slot RS of the device once set is canceled (S414).

  When the wireless communication device 10 first receives the RTS addressed to the other device (S415), the wireless communication device 10 identifies the start slot SS where the transmission of the data addressed to the other device is started from the timing of the request slot QS of the RTS addressed to the other device. (S416).

  Thereafter, when receiving the RTS addressed to the own device (S417), the wireless communication device 10 acquires and stores the data length information of the data addressed to the own device (S418), and performs this operation at the end of the request slot QS position. Repeat until it exceeds (S419).

  Here, when the wireless communication device 10 receives the RTS addressed to itself (S420), the XTS frame is set (S421), the data addressed to the other device is received (S422), and the start slot SS of the data addressed to the other device is exceeded. If not until (S423), an XTS frame is transmitted (S424). On the other hand, if there is reception of data destined for another device before the start slot SS for data destined for another device is exceeded, the wireless communication device 10 proceeds to S432 and returns an XTS after the end of the data transmission.

  The wireless communication device 10 receives the data addressed to itself (S425), receives the data payload (S426), and sets the ACK information only when the data is received normally (S427) (S428). ). Further, if there is an ACK return request for data addressed to the own apparatus (S429), an ACK frame is constructed and transmitted (S430).

  In addition, when receiving data addressed to another device (S431), the wireless communication device 10 acquires the duration information of the corresponding data, and loops the process until the time described in the duration information elapses (S432). ). After the elapse of the time described in the duration information, when the wireless communication device 10 receives the RTS addressed to itself (S433), the wireless communication device 10 acquires the data duration information 717 (S434), and the reception access control is set for this. Compared with the remaining time of the MAS at the end, if communication is possible in the remaining time, the process proceeds to S424, the XTS frame is returned, and the reception process is continued.

  On the other hand, if communication is not possible in the remaining time and the RTS addressed to the own device is not received, the wireless communication device 10 returns to S401 if there is remaining time of the last MAS, and a series of reception processes If the remaining time is not reached, the process is terminated.

[6] Summary As described above, since the wireless communication device 10 according to the present embodiment has a plurality of request slots QS, a plurality of wireless communication devices are addressed to the own device in different request slots QS or other devices. The addressed RTS may be received. Here, if it is assumed that only a single request slot QS is provided, the wireless communication device 10 may normally receive only one RTS even if RTSs are transmitted from a plurality of wireless communication devices. On the other hand, the wireless communication device 10 can normally receive RTS from a plurality of wireless communication devices in different time zones as described above. As a result, the CTS response control unit 136 can determine whether or not CTS transmission is possible according to the RTS reception status in the plurality of request slots QS, thereby realizing smoother communication control.

  Also, since the wireless communication device 10 according to the present embodiment has a plurality of request slots QS, the wireless communication device 10 can transmit the RTS to the request slot QS selected by the RTS transmission control unit 132. In addition, since a plurality of response slots RS are set, the wireless communication device 10 may receive response signals addressed to itself or CTSs addressed to other devices transmitted from a plurality of wireless communication devices in different response slots RS. it can. As a result, the data transmission control unit 134 can determine whether or not data transmission is possible according to the CTS reception status in the plurality of response slots RS, thereby realizing smoother communication control.

  That is, according to the present embodiment, by preparing a plurality of transmission timings of RTS and CTS, there is an effect that it is possible to easily detect a collision between RTS and CTS that could not be detected by the conventional method.

  In addition, by defining the transmission (reception) timing of RTS and CTS, there is an effect that a method for preventing a collision can be obtained in an ultra-wideband (UWB) wireless communication system that uses extremely weak signals.

  Even if RTS collision occurs, collisions can be easily detected at different slot timings, so that access control in an autonomous distributed ad hoc network in which transmission and reception are disturbed is possible.

  Also, by preparing a plurality of RTS / CTS slots, it is possible to efficiently receive CTS from the receiving side, and there is an effect that the exposed terminal problem, which has been regarded as a problem in the conventional RTS / CTS control method, can be solved. In addition, there is a method for improving the method of transmitting data in an attempt to solve the exposed terminal problem and promoting the collision by preparing a mechanism to refrain from transmission when receiving CTS from others after RTS transmission. can get.

  In addition, when receiving a CTS from another wireless communication device, it is possible to grasp that the other party is receiving data of that length and to refrain from transmission from the own device until the data reception is completed. A method of coexisting data transmission is obtained. In other words, even if the data reception of the own device is finished first, if the data reception of the other party is not finished, it waits for the ACK return from the own device, thereby solving the problem in the conventional exposed terminal problem of the technology A method is obtained.

  In addition, when the own device returns a CTS, if the CTS is received from another partner first, the transmission data of the own device is secured as a corresponding length so that an ACK can be returned for other data transmission. A coexisting method is obtained. Alternatively, when the own device returns the CTS, if the CTS is received from the other party first, the CTS return of the own device is interrupted, and after the other party's data transmission and ACK return are completed, the cross-to-send A method is obtained in which (XTS) is returned and the data addressed to the device itself is reliably received. Thus, it is possible to realize a wireless communication control method that compensates for the drawbacks of multiplexing the conventional RTS / CTS control method, in which a collision occurs in ACK return.

  In addition, when RTS competes with other wireless communication devices existing in the vicinity, when the other party's communication is completed or when the corresponding communication is not performed, a cross-to-send (XTS) is returned and the own device By receiving the destination data, a method for using the transmission path without waste is obtained. In addition, unlike the conventional wireless communication system, it is not necessary to set a waiting time for random backoff due to the occurrence of a frame collision, so that the wireless transmission path can be used efficiently.

  In addition, 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, as shown in FIG. 35, a plurality of slot groups each including a plurality of request slots QS and a plurality of response slots RS may be provided, and different priorities may be assigned to each slot group.

  FIG. 35 is an explanatory diagram showing a modification of the present embodiment. As shown in FIG. 35, in this embodiment, the request slot QS consisting of request slots QS20A, 20B and 20C with priority 1 is followed by the response slot consisting of response slots RS22A, 22B and 22C with priority 1 RS group is arranged. Further, a request slot QS group including request slots QS20D, 20E, and 20F of priority order 2 may be arranged after the response slot RS group of priority order 1. Further, a response slot RS group composed of response slots RS22D, 22EB, and 22F of priority order 2 may be arranged after the request slot QS group of priority order 2.

  In addition, each step in the processing of the wireless communication device 10 of the present specification does not necessarily have to be processed in time series in the order described in the flowchart. For example, each step in the processing of the wireless communication device 10 may include processing executed in parallel or individually (for example, parallel processing or object processing).

  Further, it is possible to create a computer program for causing hardware such as a CPU, a ROM, and a RAM built in the wireless communication device 10 to perform the same functions as the components of the wireless communication device 10 described above. A storage medium storing the computer program is also provided. Moreover, a series of processing can also be realized by hardware by configuring each functional block shown in the functional block diagram of FIG. 19 with hardware.

It is explanatory drawing which showed the structure of the radio | wireless communications system concerning this embodiment. It is explanatory drawing which showed the structural example of the super frame. It is explanatory drawing which showed the structural example of the PHY frame. It is explanatory drawing which showed the structural example of the beacon frame. It is explanatory drawing which showed the structural example of the DRP reservation information element which is the information element contained in a beacon. It is explanatory drawing which showed the structural example of the PCA utilization notification information element which is an information element contained in a beacon. It is explanatory drawing which showed the other structural example of the PCA utilization notification information element which is an information element contained in a beacon. It is explanatory drawing which showed the structural example of the RTS frame. It is explanatory drawing which showed the structural example of the CTS frame. It is explanatory drawing which showed the structural example of the cross-to-send (XTS) frame. It is explanatory drawing which showed the structural example of the data frame. It is explanatory drawing which showed the structural example of the ACK (immediate ack) frame. It is explanatory drawing which showed the structural example of the block ACK frame. It is explanatory drawing which showed the mode of the communication control by the radio | wireless communication apparatus relevant to this embodiment. It is explanatory drawing which showed the mode of the other communication control by the radio | wireless communication apparatus relevant to this embodiment. It is explanatory drawing which showed the mode of the other communication control by the radio | wireless communication apparatus relevant to this embodiment. It is explanatory drawing which showed the mode of the other communication control by the radio | wireless communication apparatus 14 relevant to this embodiment. It is explanatory drawing which showed slot arrangement | positioning in the conventional radio | wireless communications system. It is the functional block diagram which showed the structure of the radio | wireless communication apparatus concerning this embodiment. It is explanatory drawing which showed the example of slot arrangement | positioning by a timing management part. It is explanatory drawing which showed the example of slot arrangement | positioning by a timing management part. It is explanatory drawing which showed the example of slot arrangement | positioning by a timing management part. It is explanatory drawing which showed the example of communication control by this embodiment. It is explanatory drawing which showed the other example of communication control by this embodiment. It is explanatory drawing which showed the other example of communication control by this embodiment. It is explanatory drawing which showed the other example of communication control by this embodiment. It is explanatory drawing which showed the other example of communication control by this embodiment. It is explanatory drawing which showed the other example of communication control by this embodiment. It is explanatory drawing which showed the other example of communication control by this embodiment. It is explanatory drawing which showed the other example of communication control by this embodiment. It is explanatory drawing which showed the other example of communication control by this embodiment. It is the flowchart which showed the flow of the radio | wireless communication method performed in the radio | wireless communication apparatus concerning this embodiment. It is the flowchart which showed the flow of the transmission access control in this embodiment. It is the flowchart which showed the flow of the reception access control in this embodiment. It is explanatory drawing which showed the modification of this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Antenna 102 Reception processing part 128 Timing management part 130 Communication control part 132 RTS transmission control part 134 Data transmission control part 136 CTS response control part 138 XTS response control part 140 ACK response control part 145 Transmission processing part

Claims (16)

A wireless communication device that receives a transmission request signal from another wireless communication device, transmits a response signal to the transmission request signal to the other wireless communication device, and then transmits a data signal from the other wireless communication device. :
A time zone setting unit for setting a plurality of request time zones for receiving the transmission request signal and a plurality of response time zones arranged after the plurality of request time zones for transmitting the response signal; ;
A communication unit that communicates with surrounding wireless communication devices;
A response control unit that controls whether or not the response signal can be transmitted from the communication unit in the plurality of response time periods according to the reception status of the transmission request signal from the surrounding wireless communication devices in the plurality of request time periods. When;
A wireless communication device comprising:   When the communication unit receives a transmission request signal addressed to its own device in any of the plurality of request time zones and does not receive a transmission request signal addressed to another device, the response control unit is configured to The wireless communication apparatus according to claim 1, wherein a response signal to the transmission request signal addressed to the own apparatus is transmitted to the communication unit in any of the time zones.   When the communication unit receives a transmission request signal addressed to its own device in any of the plurality of request time zones and a transmission request signal addressed to another device, the response control unit The wireless communication apparatus according to claim 1, wherein the communication unit is not allowed to transmit the response signal in a response time zone.   The communication unit receives a transmission request signal addressed to the own device in any of the plurality of request time zones, receives a transmission request signal addressed to another device, and based on the transmission request signal addressed to the other device If the data signal corresponding to the transmission request signal addressed to the other device is not received after the transmission start timing of the data signal corresponding to the estimated transmission request signal addressed to the other device, the transmission request signal addressed to the own device The wireless communication apparatus according to claim 1, further comprising a delay response control unit that causes the communication unit to transmit a delay response signal that responds with a delay to the communication unit. An estimation unit for estimating a transmission end position of a data signal transmitted by surrounding wireless communication devices;
Confirmation control unit for causing the communication unit to transmit a confirmation signal for the data signal transmitted from the other wireless communication device to the communication unit after the transmission end position of the data signal transmitted by the surrounding wireless communication device When;
The wireless communication apparatus according to claim 1, further comprising: The communication unit receives a transmission request signal addressed to itself from another wireless communication device in any of the plurality of request time zones, and receives a response signal addressed to another device in any of the plurality of response time zones. if you did this,
The response control unit does not cause the communication unit to transmit the response signal to the other wireless communication device in the plurality of response time zones,
An estimation unit for estimating a transmission end position of a data signal corresponding to a response signal addressed to the other device;
After the transmission end position of the data signal corresponding to the response signal addressed to the other device estimated by the estimation unit, a delay response signal that responds with a delay to the transmission request signal is transmitted from the communication unit to the other wireless communication device. The wireless communication apparatus according to claim 1, further comprising a delay response control unit that transmits to the wireless communication apparatus. A wireless communication device that transmits a transmission request signal to another wireless communication device and starts transmission of a data signal after receiving a response signal to the transmission request signal from the other wireless communication device:
A time zone setting unit for setting a plurality of request time zones for transmitting the transmission request signal and a plurality of response time zones arranged after the plurality of request time zones for receiving the response signal; ;
A time zone selection unit that selects any one of the plurality of request time zones;
A communication unit that transmits the transmission request signal to the other wireless communication device during the request time period selected by the time period selection unit;
A transmission control unit that controls whether or not to transmit the data signal from the communication unit according to the reception status of the response signal from the other wireless communication device in the plurality of response time zones;
A wireless communication device comprising:   The communication unit does not receive the response signal from the other wireless communication device in the plurality of response time zones, and the other wireless communication device responds with a delay to the transmission request signal within a predetermined period. 8. The wireless communication according to claim 7, wherein when the delayed response signal is received, the transmission control unit causes the communication unit to transmit the data signal after the delayed response signal is received. apparatus.   The communication unit does not receive the response signal from the other wireless communication device in the plurality of response time zones, and the other wireless communication device responds with a delay to the transmission request signal within a predetermined period. The wireless communication apparatus according to claim 7, wherein when the delayed response signal to be received is not received, the communication unit transmits the transmission request signal again in the request time zone selected by the selection unit.   The transmission control unit, when the communication unit receives a data signal not addressed to the own device, the data signal from the communication unit in a time zone in which a confirmation signal for the data signal not addressed to the own device will be transmitted. The wireless communication device according to claim 7, wherein transmission of the wireless communication device is stopped.   When the communication unit receives a response signal addressed to another device in any of the plurality of response time zones, the transmission control unit does not cause the communication unit to transmit the data signal, The wireless communication apparatus according to claim 7. Executed in a wireless communication device that receives a transmission request signal from another wireless communication device, transmits a response signal to the transmission request signal to the other wireless communication device, and then transmits a data signal from the other wireless communication device The wireless communication method to be used is:
Setting a plurality of request time zones for receiving the transmission request signal and a plurality of response time zones arranged after the plurality of request time zones for transmitting the response signal;
Controlling the availability of transmission of the response signal in the plurality of response time zones according to the reception status of the transmission request signal from the surrounding wireless communication devices in the plurality of request time zones;
A wireless communication method comprising: A wireless communication method executed in a wireless communication device that transmits a transmission request signal to another wireless communication device and starts transmission of a data signal after receiving a response signal to the transmission request signal from the other wireless communication device. :
Setting a plurality of request time zones for transmitting the transmission request signal and a plurality of response time zones arranged after the plurality of request time zones for receiving the response signal;
Selecting any one of the plurality of request time zones;
Transmitting the transmission request signal to the other wireless communication device during a request time period selected by the time period selection unit;
Controlling whether or not to transmit the data signal according to the reception status of the response signal from the other wireless communication device in the plurality of response time zones;
A wireless communication method comprising: Computer
A wireless communication device that receives a transmission request signal from another wireless communication device, transmits a response signal to the transmission request signal to the other wireless communication device, and then transmits a data signal from the other wireless communication device. :
A time zone setting unit for setting a plurality of request time zones for receiving the transmission request signal and a plurality of response time zones arranged after the plurality of request time zones for transmitting the response signal; ;
A communication unit that communicates with surrounding wireless communication devices;
A response control unit that controls whether or not the response signal can be transmitted from the communication unit in the plurality of response time periods according to the reception status of the transmission request signal from the surrounding wireless communication devices in the plurality of request time periods. When;
A program for causing a wireless communication apparatus to function. Computer
A wireless communication device that transmits a transmission request signal to another wireless communication device and starts transmission of a data signal after receiving a response signal to the transmission request signal from the other wireless communication device:
A time zone setting unit for setting a plurality of request time zones for transmitting the transmission request signal and a plurality of response time zones arranged after the plurality of request time zones for receiving the response signal; ;
A time zone selection unit that selects any one of the plurality of request time zones;
A communication unit that transmits the transmission request signal to the other wireless communication device during the request time period selected by the time period selection unit;
A transmission control unit that controls whether or not to transmit the data signal from the communication unit according to the reception status of the response signal from the other wireless communication device in the plurality of response time zones;
A program for causing a wireless communication apparatus to function. A wireless communication system including a first wireless communication device and a second wireless communication device:
The first wireless communication apparatus includes a plurality of request time zones for transmitting a transmission request signal and a plurality of time zones arranged after the plurality of request time zones for receiving a response signal in response to the transmission request signal. A response time zone, and a time zone setting unit for setting;
A time zone selection unit that selects any one of the plurality of request time zones;
A communication unit that transmits the transmission request signal to the other wireless communication device during the request time period selected by the time period selection unit;
With
The second wireless communication device is configured to perform the first wireless communication of the response signal in the plurality of response time zones according to a reception status of the transmission request signal from a surrounding wireless communication device in the plurality of request time zones. A response control unit that controls whether or not transmission to the device is possible;
Whether the first radio communication device can transmit the data signal to the second radio communication device according to the reception status of the response signal from the second radio communication device in the plurality of response time zones. A wireless communication system, wherein

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