JP2010178086A - Radio equipment and method for controlling thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To avoid the complexity in managing whether a band is reserved or not. <P>SOLUTION: The radio communication equipment includes: a first communication unit which uses a first frequency band for communication, a second communication unit which uses a second frequency band for communication, and a management unit which manages reservation status of the first frequency band and the second frequency band by other radio equipment. When a frame to reserve the first frequency band for a first period is received by the first communication unit, the management unit determines that the first frequency band and the second frequency band are reserved for the first period. When a frame to reserve the second frequency band for a second period is received by the second communication unit, the management unit determines that the first frequency band and the second frequency band are reserved for the second period. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a radio apparatus and a control method thereof.

  In the IEEE 802.11 standard, the CSMA / CA system is adopted as an access control system. In one basic service set (BSS), a plurality of wireless devices use one frequency band, and frames cannot be transmitted simultaneously. Each wireless device observes a radio wave (carrier sense) and determines whether a band is reserved by another wireless device (NAV (Network Allocation Vector) is set). After confirming that communication is not being performed, a frame is transmitted (Non-Patent Document 1).

  The above-described CSMA / CA scheme is designed on the basis of being omnidirectional so that radio waves transmitted by each wireless device are transmitted in all directions. As an access control method (CSMA / CA method) when radio waves transmitted by each wireless device have directivity, each wireless device performs band reservation (NAV) for each space (sector) divided by direction. Has been proposed (Patent Document 1).

  However, in the technique disclosed in Patent Document 1, each wireless device needs to manage whether or not a band is reserved for each of a plurality of sectors, and there is a problem that device implementation becomes complicated. .

  In addition, each wireless device has a millimeter wave (an electromagnetic wave in a frequency band of 30 GHz to less than 300 GHz. For example, 57-66 GHz band) and a microwave (an electromagnetic wave in a frequency band of 3 GHz to less than 30 GHz. For example, a 5 GHz band and a 2.4 GHz band. ) To communicate with each other. Although millimeter waves have high directivity and radio waves reach only a narrow range, the transmission speed is high. Although microwaves can be transmitted omnidirectionally and radio waves can reach a wide range, the transmission speed is lower than that of millimeter waves. In consideration of the characteristics of these frequency bands, a method in which each wireless device communicates a frame (control frame) having control information with microwaves in an omnidirectional manner, and communicates a data frame with millimeter waves by space division multiplexing. Has been proposed (Non-Patent Document 2).

  However, in the technology according to Non-Patent Document 2, each wireless device uses only a microwave for communication of a control frame and does not use for communication of a data frame. is there.

JP 2006-186603 A

IEEE Std 802.11-1999 2003 Edition IEEE802.11-08 / 0349r1

  The present invention has been made in view of the above, and in a wireless communication system using a plurality of wireless communication systems, a wireless device capable of avoiding the complexity of managing whether or not a bandwidth is reserved and An object is to provide a control method thereof.

  In order to achieve the above object, a wireless device according to an embodiment of the present invention includes a first communication unit that communicates in a first frequency band, a second communication unit that communicates in a second frequency band, and other wireless devices. A management unit that manages a reservation state of the first frequency band and the second frequency band, and when the first communication unit receives a frame that reserves the first frequency band for a first period, the management unit The first frequency band and the second frequency band are reserved for the first period, and when the second communication unit receives a frame for reserving the second frequency band for the second period, the management is performed. A wireless device in which the first frequency band and the second frequency band are reserved for the second period.

  According to the present invention, in a wireless communication system using a plurality of wireless communication systems, it is possible to avoid the complexity of managing a plurality of whether or not a bandwidth is reserved.

1 is a diagram showing a wireless system according to a first embodiment of the present invention. 1 is a block diagram showing a configuration of a wireless communication apparatus according to a first embodiment of the present invention. FIG. 3 is a sequence diagram showing frames transmitted and received in the wireless system according to the first embodiment of the present invention. 3 is a flowchart showing the operation of the wireless device according to the first embodiment of the present invention. 3 is a flowchart showing the operation of the wireless device according to the first embodiment of the present invention. 3 is a flowchart showing the operation of the wireless device according to the first embodiment of the present invention. The sequence diagram which shows the flame | frame transmitted / received by the radio | wireless system which concerns on the modification 1 of the 1st Embodiment of this invention. The sequence diagram which shows the flame | frame transmitted / received by the radio | wireless system which concerns on the modification 2 of the 1st Embodiment of this invention. 9 is a flowchart showing the operation of a wireless device according to a third modification of the first embodiment of the present invention. 9 is a flowchart showing the operation of a wireless device according to a fourth modification of the first embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described. In the following description, the first frequency band is assumed to be a millimeter wave band, and the second frequency band is assumed to be a microwave band. The first frequency band and the second frequency band may be the same frequency band, and different frequency bands. The first frequency band and the second frequency band are different frequency bands other than the frequency band other than millimeter wave and microwave. May be.

(First embodiment)
FIG. 1 is a diagram showing a wireless system 100 according to the first embodiment of the present invention.

  The wireless system includes wireless devices STA1 to STA5. The wireless devices STA1 to STA5 constitute one BSS (Basic Service Set). The positional relationship between the wireless devices STA1 to STA5 is as shown in FIG. The wireless devices STA1 to STA5 communicate using the millimeter wave band and the microwave band. The radio waves transmitted by each wireless device STA1 to STA5 in a non-directional (omni) manner using the microwave band reach the entire wireless system. The reach of radio waves transmitted by the wireless device STA1 using the millimeter wave band is a range indicated by AREA1 in FIG. AREA1 includes wireless devices STA2 and STA3. The reach of radio waves transmitted by the wireless device STA2 using millimeter waves is a range indicated by AREA2 in FIG. AREA2 includes a wireless device STA1.

  The access control method used by the wireless devices STA1 to STA5 can be applied to all wireless communication methods. In the following, a typical CSMA / CA method as a distributed control method, particularly a method defined in the IEEE 802.11 standard will be described as an example.

  FIG. 2 is a block diagram showing a configuration of radio apparatuses STA1 to STA5.

  The radio apparatuses STA1 to STA5 include a millimeter wave communication unit 10, a microwave communication unit 20, a control unit 30, and a NAV management unit 40.

  The millimeter wave communication unit 10 performs wireless communication using the millimeter wave band.

  The microwave communication unit 20 performs wireless communication using a microwave band.

  The control unit 30 performs communication control in cooperation with both the millimeter wave band and the microwave band. When transmitting a frame, the control unit 30 controls whether communication is performed using one of the millimeter wave band and the microwave band or both. The control unit 30 controls frame transmission timing.

  The NAV management unit 40 manages the reservation status by other wireless devices for both the millimeter wave band and the microwave band. The NAV management unit 40 manages bandwidth reservation (NAV) set by other wireless devices for both the millimeter wave band and the microwave band.

  The transmission queue 50 stores frames to be transmitted.

  The application unit 60 performs upper layer processing. The application unit 60 generates data to be transmitted. The application unit 60 stores in a storage unit (not shown) whether or not the communication partner wireless device can communicate using the millimeter wave band.

  FIG. 3 is a sequence diagram when data is transmitted from the wireless device STA1 to the wireless device STA2. FIG. 4 is a flowchart showing the operation of the wireless device STA1.

  First, the wireless device STA1 performs settings for connecting to the BSS. The wireless device STA1 performs association and authentication (setup operation) with respect to the access point of the BSS. The application unit 60 of the wireless device STA1 performs a preliminary check as to whether or not there is a possibility of wireless communication in the millimeter wave band with other wireless devices in the BSS at the time of the setup work or after the setup work is completed. The application unit 60 of the wireless device STA1 displays information on whether or not the other wireless devices STA2 to STA5 belonging to the BSS have the possibility of wireless communication using the millimeter wave band as the connection destination wireless device that has been set up. Along with the list of devices, it is stored in a built-in storage unit (step S101). The application unit 60 of the wireless device STA1 adjusts parameters such as weighting of antennas when performing wireless communication in the millimeter wave band for each of the other wireless devices STA2 to STA5 belonging to the BSS. And store it in the built-in storage unit. In the example of FIG. 3, the wireless devices STA1 to STA5 can perform communication using the millimeter wave band.

  Next, a data transmission request is generated through an upper layer process by the application unit 60 of the wireless device STA1, which is the data transmission side (Originator) (step S102). It is assumed that a data transmission request addressed to the wireless device STA2 is generated.

  Next, based on the information stored in the built-in storage unit, the application unit 60 determines whether or not the destination wireless device STA2 may perform communication using the millimeter wave band from the destination of the data to be transmitted. Judgment is made (step S103).

  If there is no possibility that the destination wireless device STA2 performs wireless communication using the millimeter wave band (“No” in step S103), the wireless device STA1 requests a request frame (RTS: request to transmit data to the wireless device STA2). (Request To Send) is transmitted in the microwave band (step S104), and a permission frame (CTS: Clear To Send) permitting data transmission is received from the wireless apparatus STA2 in the microwave band (step S105). Data (Aggregated-MPDU) is transmitted in the microwave band (step S108).

  On the other hand, when the destination wireless device STA2 may perform wireless communication using the millimeter wave band (“Yes” in step S103), the application unit 60 adds information indicating the possibility of transmission in the millimeter wave band. The processed data (frame) is written to the transmission queue 50.

  Next, the transmission queue 50 outputs a frame to which information indicating the possibility of transmission in the millimeter wave band is added to the control unit 30.

  Next, the control unit 30 recognizing that there is a possibility of transmission in the millimeter wave band, an RTS frame transmitted from the millimeter wave band and a microwave to confirm whether communication in the millimeter wave band is possible. And an RTS frame to be transmitted in the band. Next, after acquiring the transmission right, the control unit 30 controls the millimeter wave communication unit 10 and the microwave communication unit 20 to simultaneously transmit RTS frames (step S106). Here, since the transmission rate of the millimeter wave band is larger than the transmission rate of the microwave band, the control unit 30 sets the frame time length of the RTS frame transmitted in the millimeter wave band and the frame of the RTS frame transmitted in the microwave band. The RTS frame transmitted in the microwave band is padded so that the time length is the same. In the RTS frame, the same period as the period for reserving the millimeter wave band and the microwave band (band reservation period: period for setting the NAV) is described in the Duration field.

  Next, after transmitting the RTS frame in the microwave band and the millimeter wave band, the wireless device STA1 waits between the millimeter wave communication unit 10 and the microwave communication unit 20 in order to receive the CTS frame. Become.

  The wireless device STA2 which is the data receiving side (Recipient) returns a CTS frame in the frequency band in which the RTS frame is received so that the CTS frame can be received after the SIFS period has elapsed since the wireless device STA1 transmitted the RTS frame. To do. When the radio apparatus STA2 receives the RTS frame only in the microwave band, the radio apparatus STA2 returns a CTS frame in the microwave band. When the radio apparatus STA2 receives an RTS frame only in the millimeter wave band, the radio apparatus STA2 returns a CTS frame in the millimeter wave band. When receiving the RTS frame in the microwave band and the millimeter wave band, the wireless device STA2 returns a CTS frame in the microwave band and the millimeter wave band. In the example of FIG. 3, the radio apparatus STA2 receives an RTS frame and returns a CTS frame in the microwave band and the millimeter wave band.

  Next, the control unit 30 of the wireless device STA1 determines whether a CTS frame is received from the wireless device STA2 in the millimeter wave band (step S107).

  When the CTS frame is received from the wireless device STA2 only in the microwave band (“No” in step S107), the wireless device STA1 cannot determine millimeter-wave communication but can determine that microwave communication is possible. Therefore, the control unit 30 of the wireless device STA1 reads the frame from the transmission queue 50 and transmits a data frame (MPDU or A-MPDU) via the microwave communication unit 20 (step S108). The A-MPDU includes a plurality of MPDUs.

  On the other hand, when the CTS frame is received from the radio apparatus STA2 in the millimeter wave band, or when the CTS frame is received in the millimeter wave band and the microwave band ("Yes" in step S107), the radio apparatus STA1 is in the millimeter wave band. It can be determined that communication is possible. When communication in the millimeter wave band and the microwave band is possible, the wireless device STA1 transmits a data frame using the millimeter wave band having a high transmission rate. The control unit 30 of the wireless device STA1 transmits a data frame (MPDU or A-MPDU) via the millimeter wave communication unit 10 (step S109). Also, the control unit 30 of the wireless device STA1 releases a cancellation frame (Cf− in which the value of the Duration field is set to “0”) via the microwave communication unit 20 to cancel the NAV of the microwave band set by the RTS frame. end frame). In this way, even when the wireless device STA1 is communicating with millimeter waves, communication using the microwave band by other wireless devices can be performed, and the frequency band utilization efficiency can be increased. In the example of FIG. 3, the control unit 30 of the wireless device STA1 simultaneously performs transmission of A-MPDU via the millimeter wave communication unit 10 and transmission of Cf-end frames via the microwave communication unit 20.

  Next, the control unit 30 receives the microwave communication from the microwave communication unit 20 until the transmission of the data frame by the millimeter wave is completed after receiving the Cf-end frame (Duration field value “0”) transmission completion notification. The power supply to the unit 20 is cut off (step S110). By doing in this way, the power consumption of radio | wireless apparatus STA1 can be reduced.

  As described above, by performing the operations shown in FIG. 3 and FIG. 4, the wireless device STA1 realizes management of the reservation state by other wireless devices in the millimeter wave band and the microwave band with one NAV management unit 40. And the complexity of the implementation can be avoided. After acquiring the right to transmit data, the wireless device STA1 can determine the frequency band used for data frame transmission according to the communication status of the millimeter wave band and the microwave band. The radio apparatus STA1 can improve frequency utilization efficiency by separating communication in the highly directional millimeter wave band and communication in the omnidirectional microwave band.

  FIG. 5 is a flowchart showing an operation of the wireless device STA3 when the wireless device STA1 transmits data to the wireless device STA2 (FIG. 3).

  First, the wireless device STA3 turns on the reception functions of both the millimeter wave communication unit 10 and the microwave communication unit 20, and is in a standby state in both the millimeter wave band and the microwave band. Then, the wireless device STA3 simultaneously receives the RTS frame transmitted from the wireless device STA1 to the wireless device STA2 from both the millimeter wave band and the microwave band (step S201).

  Next, the control unit 30 of the wireless device STA3 includes the NAV setting period described in the RTS frame received in the millimeter wave band and the NAV setting period described in the RTS frame received in the microwave band. One of the longer periods is notified to the NAV management unit 40. (Step S202). In the example of FIG. 3, the control unit 30 of the wireless device STA3 sets the NAV setting period described in the RTS frame received in the millimeter wave band and the NAV setting described in the RTS frame received in the microwave band. Since the period is the same, either period may be output to the NAV management unit 40.

  Next, when the CTS frame is simultaneously transmitted from the wireless device STA2 to the wireless device STA1 in the millimeter wave band and the microwave band, the wireless device STA3 receives the CTS frame in the microwave band (step S203).

  Next, the control unit 30 of the wireless device STA3 notifies the NAV management unit 40 of the NAV setting period described in the CTS frame received in the microwave band. It is assumed that the NAV management unit 40 of the wireless device STA3 sets the NAV by the wireless device STA1 in the millimeter wave band and the microwave band for the period notified from the control unit 30 (step S204). In the IEEE802.11 standard, when a CTS frame as a response is not received after receiving an RTS frame addressed to another wireless device, the NAV set in the RTS frame is canceled. However, even if a CTS frame cannot be received in the millimeter wave band after receiving an RTS frame addressed to another wireless device in the millimeter wave band / microwave band, a CTS frame is received in the microwave band Therefore, the NAV in the millimeter wave band / microwave band is not canceled, and the NAV set in the RTS frame and the NAV set in the CTS frame remain valid.

  Next, when A-MPDU is transmitted from the wireless device STA1 to the wireless device STA2 in the millimeter wave band and Cf-end is transmitted in the microwave band, the wireless device STA3 receives the A-MDPU by millimeter wave. At the same time, the Cf-end frame is received in the microwave band (step S105).

  Next, the control unit 30 of the wireless device STA3 sets the NAV setting period described in the A-MPDU received in the millimeter wave band and the NAV setting period described in the Cf-end frame received in the microwave band. The NAV management unit 40 is notified of the longer period. Since the NAV setting period described in the Cf-end frame is “0”, the control unit 30 of the wireless device STA3 notifies the NAV management unit 40 of the NAV setting period described in the A-MPDU. It is assumed that the NAV management unit 40 of the wireless device STA3 sets the NAV by the wireless device STA1 in the millimeter wave band and the microwave band for the period notified from the control unit 30 (step S206).

  Thereafter, the wireless device STA3 resets the NAV according to the exchange between the A-MPDU frame and the BlockAck (BA) frame transmitted / received in the millimeter wave band during the TXOP period (step S207). By doing so, it is possible to avoid the wireless device STA3 from performing communication that causes interference in frame exchange between the wireless device STA1 and the wireless device STA2.

  FIG. 6 is a flowchart showing the operation of the wireless device STA4 when the wireless device STA1 transmits data to the wireless device STA2 (FIG. 3). The wireless device STA5 operates in the same manner.

  First, the wireless device STA4 turns on the reception functions of both the millimeter wave communication unit 10 and the microwave communication unit 20, and is in a standby state in both the millimeter wave band and the microwave band. When the RTS frame is transmitted from the wireless device STA1 to the wireless device STA2 in the millimeter wave band and the microwave band, the wireless device STA4 receives the RTS frame addressed to the wireless device STA2 from the wireless device STA1 only in the microwave band ( Step S301).

  Next, the control unit 30 of the wireless device STA3 notifies the NAV management unit 40 of the NAV setting period described in the RTS frame received in the microwave band. It is assumed that the NAV management unit 40 of the wireless device STA3 sets the NAV by the wireless device STA1 in the millimeter wave band and the microwave band for the period notified from the control unit 30 (step S302).

  Next, when the CTS frame is simultaneously transmitted from the wireless device STA2 to the wireless device STA1 in the millimeter wave band and the microwave band, the wireless device STA4 receives the CTS frame in the microwave band (step S303).

  Next, the control unit 30 of the wireless device STA4 notifies the NAV management unit 40 of the NAV setting period described in the CTS frame received in the microwave band. It is assumed that the NAV management unit 40 of the wireless device STA4 sets the NAV in the millimeter wave band and the microwave band for the period notified from the control unit 30 (step S304).

  Next, when A-MPDU is transmitted from the wireless device STA1 to the wireless device STA2 in the millimeter wave band and Cf-end is transmitted in the microwave band, the wireless device STA4 receives the Cf-end frame in the microwave band. (Step S305).

  Next, the control unit 30 of the wireless device STA4 recognizes that the cancellation of the NAV has been notified by receiving the Cf-end frame in the microwave band. The control unit 30 that has recognized the cancellation of the NAV notifies the NAV management unit 40 of the cancellation of the NAV. (Step S306).

  Thereafter, when there is a data transmission request, the wireless device STA4 performs back-off processing in order to acquire a transmission right regardless of whether the wireless device STA1 and the wireless device STA2 perform communication in the millimeter wave band. To start. Even if the wireless device STA4 starts communication in the microwave band, the wireless device STA1 and the wireless device STA2 do not interfere with communication in the millimeter wave band. Even if the wireless device STA4 starts communication in the millimeter wave band, the radio wave (millimeter wave) transmitted by the wireless device STA4 and the radio wave (millimeter wave) transmitted by the wireless devices STA1 and 2 are spatially divided. The wireless device STA1 and the wireless device STA2 do not interfere with communication in the millimeter wave band. Even if the wireless device STA4 communicates with the microwave, the wireless device STA1 and the wireless device STA2 are communicating with each other using the millimeter wave, and the microwave power is turned off during this period, so there is no influence. .

  As described above, according to the wireless system 100 according to the first embodiment, both the millimeter wave band and the microwave band are used for communication, and the reservation status of these bands is centrally managed. In addition, it is possible to avoid the complexity of mounting a device for managing whether or not each band is reserved.

  According to the wireless system 100 according to the first embodiment, while one NAV management unit 40 manages whether or not each band is reserved, while other wireless devices are communicating in the millimeter wave band In addition, since it is possible to start communication in the millimeter wave band and the microwave band, the frequency efficiency can be improved.

(Modification 1 of the first embodiment)
In the first embodiment, the description has been focused on the case where data frames are communicated from the wireless device STA1 to the wireless device STA2 using millimeter waves. In the first modification of the first embodiment, the radio apparatus STA1 receives the CTS frame only in the microwave band even though the radio apparatus STA1 transmits the RTS frame in the millimeter wave band and the microwave band in step S106 of FIG. (No in step S107 in FIG. 4) will be described.

  FIG. 7 is a sequence diagram when the wireless device STA1 according to the first modification of the first embodiment transmits data to the wireless device STA2.

  After receiving the CTS frame from the radio apparatus STA2 only in the microwave band, the control unit 30 of the radio apparatus STA1 changes the frequency band for transmitting the data frame from the millimeter wave to the microwave.

  The transmission rate of the millimeter wave band is larger than the transmission rate of the microwave band. Therefore, if the wireless device STA1 uses the millimeter wave band, even if the data frame transmission is completed during the NAV period set in the RTS frame, it is set in the RTS frame because the microwave band is used. Data frame transmission may not be completed during the NAV period. Therefore, the wireless device STA1 performs at least one of the following three processes before transmitting a data frame in the microwave band.

  [First Processing] When the control unit 30 of the wireless device STA1 creates an A-MPDU before receiving the CTS frame, the control unit 30 takes out the frame from the transmission queue 50 and reduces the number of frames to be aggregated. -Create a new MPDU. In this way, the wireless device STA1 can complete the transmission of the data frame during the NAV period set by the RTS frame.

  [Second Processing] The control unit 30 of the wireless device STA1 reduces the number of A-MPDUs transmitted during the NAV period set by the RTS frame. In this way, the wireless device STA1 can complete the transmission of the data frame during the NAV period set by the RTS frame.

  [Third Process] The control unit 30 of the wireless device STA1 resets a large value in the Duration field of the data frame (A-MPDU) transmitted in the microwave band in order to extend the NAV period. By doing so, it is not necessary to perform processing (re-aggregation processing) for reducing the number of MPDUs included in the data frame transmitted by the wireless device STA1.

  As described above, the wireless device STA1 performs the [first process], the [second process], or the [third process] before transmitting the data frame in the microwave band (step S108), thereby using the frequency band to be used. Even if the millimeter wave band is changed to the microwave band, the transmission of the data frame can be completed during the NAV period.

  Thereafter, as illustrated in FIG. 7, the wireless devices STA1 and STA2 perform transmission / reception of the A-MPDU frame and the BlockAck frame in the microwave band. Since the microwave band is reserved (NAV is set) while the wireless device STA1 and the wireless device STA2 communicate with each other in the microwave band, the wireless devices STA3 to STA5 and the wireless device STA2 There will be no interference with the communication.

  As described above, according to the wireless system according to the first modification of the first embodiment, when communication in the millimeter wave band is attempted but communication in the millimeter wave band cannot be performed, the frequency used for data frame transmission The band can be switched from the millimeter wave band to the microwave band. Therefore, once a transmission right is acquired, a data frame can be transmitted regardless of whether or not communication in the millimeter wave band is possible.

(Modification 2 of the first embodiment)
In the first embodiment, the wireless device STA4 omits the description of the processing after receiving the Cf-end frame from the wireless device STA1. In the second modification of the first embodiment, a case will be described in which the radio apparatus STA4 starts communication with the radio apparatus STA5 after step S306 in FIG.

  FIG. 8 is a sequence diagram when the wireless device STA4 according to the second modification of the first embodiment transmits data to the wireless device STA5.

  The radio apparatuses STA4 and 5 receive the Cf-end frame in the microwave band from the radio apparatus STA1 (step S305 in FIG. 6), and cancel the NAV in the millimeter wave band and the microwave band (step S306 in FIG. 6).

  Next, in order to acquire the transmission right, the wireless device STA4 that has generated the data transmission request observes radio waves in the fixed period (AIFS) and the backoff (Backoff) period, in the microwave band and the millimeter wave band (carrier sense). I do. This back-off period is based on the CSMA / CA system described in IEEE 802.11.

  Next, when radio waves are not observed during the fixed period and the backoff period, the radio apparatus STA4 transmits an RTS frame to the radio apparatus STA5 in the microwave band and the millimeter wave band.

  Next, the wireless device STA5 receives the RTS frame in the microwave band and the millimeter wave band.

  Next, the wireless device STA5 transmits a CTS frame in the microwave band and the millimeter wave band to the wireless device STA4.

  Next, the wireless device STA4 receives the CTS frame in the microwave band and the millimeter wave band.

  Next, the wireless device STA4 transmits a Cf-end frame in the microwave band, and transmits an A-MPDU to the wireless device STA5 in the millimeter wave band. At this time, the radio apparatuses STA1 and STA2 are shutting off the power supply to the microwave communication unit 20 or discard the frame received from the microwave communication unit 20, so that the RTS frame, the CTS frame, and the Cf-end The frame is not received by the wireless devices STA1 and STA2. Further, since the radio apparatuses STA1 and STA2 match the directivity of transmission / reception of millimeter waves with each other, they do not receive the RTS frame, CTS frame, and A-MDPU transmitted by the radio apparatuses STA4 and STA5.

  Therefore, as shown in FIG. 8, the communication between the wireless device STA1 and the wireless device STA2 and the communication between the wireless device STA4 and the wireless device STA5 are completely separated in both the microwave band and the millimeter wave band and interfere with each other. There is nothing to do.

  As described above, according to the wireless system according to the second modification of the first embodiment, the wireless device STA4 and the wireless device are in communication with the wireless device STA1 and the wireless device STA2 while communication is performed in the millimeter wave band. The STA 5 can communicate with the microwave band and the millimeter wave band. Therefore, the frequency band utilization efficiency can be improved.

  According to the wireless system according to the second modification of the first embodiment, even when communication is performed using the microwave band and the millimeter wave band, the NAV management unit 40 that centrally manages reservation information of these bands. Thus, communication between a plurality of wireless devices can be realized at the same time without interfering with each other.

(Modification 3 of the first embodiment)
In the first embodiment, the wireless devices STA1 to STA5 include the millimeter wave communication unit 10 and the microwave communication unit 20, and can perform communication in the millimeter wave band and the microwave band.

  In the third modification of the first embodiment, the wireless device STA3 communicates using only the millimeter wave band. It may be set in advance that the radio apparatus STA3 communicates using only the millimeter wave band, and the power supply to the microwave communication unit 20 is always cut off. The wireless device STA3 may include only the millimeter wave communication unit 10 without including the microwave communication unit 20.

  FIG. 9 is a flowchart showing an operation of the radio apparatus STA3 according to the third modification of the first embodiment. Note that it is assumed that the wireless devices STA1 and STA2 operate as shown in the sequence diagram of FIG.

  First, the millimeter wave communication unit 10 of the wireless device STA3 enters a reception standby state.

  Next, the wireless device STA3 receives the RTS frame transmitted from the wireless device STA1 to the wireless device STA2 in the millimeter wave band (step S401).

  Next, the control unit 30 of the wireless device STA3 notifies the NAV management unit 40 of the period for setting the NAV described in the RTS frame. It is assumed that the NAV management unit 40 of the wireless device STA3 sets the NAV for the period notified from the control unit 30 (step S402).

  Even if the wireless device STA2 transmits the CTS frame to the wireless device STA1 in the millimeter wave band and the microwave band, the wireless device STA3 does not receive the CTS frame in the millimeter wave band or the microwave band. At this time, the wireless device STA3 cancels the NAV set by receiving the RTS frame in accordance with the IEEE 802.11 standard because it cannot receive the CTS frame as a response. Thereafter, the wireless device STA3 receives the Cf-end frame from the wireless device STA1 and recognizes that the NAV has been released. Here, when the wireless devices STA1 and STA2 communicate using the millimeter wave band, the wireless device STA3 cancels the NAV as described above, but then again by the A-MPDU frame transmitted from the wireless device STA1. Set the NAV.

  As described above, even when only the millimeter wave communication unit 10 is used, the NAV management unit 40 of the wireless device STA3 can perform NAV management in the same manner as described above.

(Modification 4 of the first embodiment)
In the first embodiment, the wireless devices STA1 to STA5 include the millimeter wave communication unit 10 and the microwave communication unit 20, and can perform communication in the millimeter wave band and the microwave band.

  In the fourth modification of the first embodiment, the wireless device STA4 communicates using only the microwave band. The wireless device STA4 may be configured to perform communication using only the microwave band in advance, and the power supply to the millimeter wave communication unit 10 may be always cut off. The wireless device STA4 may include only the microwave communication unit 20 without including the millimeter wave communication unit 10.

  FIG. 10 is a flowchart illustrating an operation of the radio apparatus STA4 according to the fourth modification of the first embodiment. Note that it is assumed that the wireless devices STA1 and STA2 operate as shown in the sequence diagram of FIG.

  First, the microwave communication unit 20 of the wireless device STA4 enters a reception standby state.

  Next, when the radio apparatus STA1 transmits an RTS frame in the millimeter wave band and the microwave band to the radio apparatus STA2, the radio apparatus STA4 receives the RTS frame transmitted in the microwave band (step S401).

  Next, the control unit 30 of the wireless device STA4 notifies the NAV management unit 40 of the period for setting the NAV described in the RTS frame. It is assumed that the NAV management unit 40 of the wireless device STA4 sets the NAV in the millimeter wave band and the microwave band for the period notified from the control unit 30 (step S402).

  Next, when the radio apparatus STA2 transmits a CTS frame in the millimeter wave band and the microwave band to the radio apparatus STA1, the radio apparatus STA4 receives the CTS frame transmitted in the microwave band (step S403).

  Next, the control unit 30 of the wireless device STA4 notifies the NAV management unit 40 of the period for setting the NAV described in the CTS frame. It is assumed that the NAV management unit 40 of the wireless device STA4 sets the NAV in the millimeter wave band and the microwave band for the period notified from the control unit 30 (step S404).

  As described above, even when only the microwave communication unit 20 is used, the NAV management unit 40 of the wireless device STA4 can perform NAV management in the same manner as described above.

  Note that the present invention is not limited to the above-described embodiment and its modifications, and can be embodied by modifying the components without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment and the modifications thereof. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

STA1, STA2, STA3, STA4, STA5... Wireless device AREA1... Millimeter wave reachable area AREA2 transmitted by wireless device STA1. Millimeter wave reachable range 10 transmitted by wireless device STA2. Communication unit 20 ... Microwave communication unit 30 ... Control unit 40 ... NAV management unit 50 ... Transmission queue 60 ... Application unit 100 ... Wireless system

Claims (14)

A first communication unit that communicates in a first frequency band;
A second communication unit that communicates in the second frequency band;
A management unit for managing a reservation state of the first frequency band and the second frequency band by another wireless device;
When the first communication unit receives a frame that reserves the first frequency band for the first period, the management unit assumes that the first frequency band and the second frequency band are reserved for the first period. ,
When the second communication unit receives a frame that reserves the second frequency band for the second period, the management unit is configured to reserve the first frequency band and the second frequency band for the second period. Wireless device to do.   When the first communication unit receives a frame for canceling the reservation of the first frequency band and the second communication unit does not receive the frame, the management unit performs the first frequency band and the first frequency band. The wireless device according to claim 1, wherein the reservation for the two frequency bands is canceled.   When the frame that reserves the first frequency band for the first period is received by the first communication unit and the frame that reserves the second frequency band for the second period is received by the second communication unit, the management The wireless device according to claim 1, wherein the unit reserves the first frequency band and the second frequency band for a long period of time between the first period and the second period.   The reach range of the radio wave transmitted by the first communication unit in the first frequency band is wider than the reach range of the radio wave transmitted by the second communication unit in the second frequency band. The wireless device according to any one of claims 1 to 3. When the first frequency band and the second frequency band are not reserved by another wireless device, the first communication unit and the second communication unit request the first wireless device to transmit a data frame. Send a request frame to
When the first communication unit and the second communication unit receive a permission frame that is a response to the transmission request frame and permits transmission of a data frame from the first wireless device, the second communication unit Transmitting a data frame to the first wireless device;
The request frame transmitted by the first communication unit describes a period during which the wireless device reserves the first frequency band,
5. The request frame transmitted by the second communication unit includes a period during which the radio apparatus reserves the second frequency band. 6. Wireless devices.   The first communication unit and the second communication unit receive the permission frame from the first wireless device, and after the second communication unit transmits the data frame to the first wireless device, the first communication unit The wireless device according to claim 5, wherein the unit transmits a release frame for releasing the reservation of the first frequency band.   The first communication unit and the second communication unit receive the permission frame from the first wireless device, and after the second communication unit transmits the data frame to the first wireless device, the first communication unit The wireless device according to claim 5, wherein power supply to the unit is cut off. When the first frequency band and the second frequency band are not reserved by another wireless device, the first communication unit and the second communication unit request the first wireless device to transmit a data frame. Send a request frame to
When either one of the first communication unit and the second communication unit receives a permission frame that is a response to the request frame and permits transmission of a data frame from the first wireless device, the permission is given. 5. The radio apparatus according to claim 1, wherein one radio unit that receives the frame transmits a data frame to the first radio apparatus. 6.   After the first communication unit and the second communication unit receive a request frame that is destined for another wireless device and requests transmission of a data frame, the response of the request frame When the first communication unit and the second communication unit do not receive a permission frame permitting transmission, the management unit cancels the reservation of the first frequency band and the second frequency band by the request frame. The wireless device according to claim 1, wherein the wireless device is a wireless device.   After the first communication unit and the second communication unit have received the request frame, the second communication unit has not received the permission frame, but the first communication unit has received the permission frame The radio apparatus according to claim 9, wherein the management unit does not cancel the reservation of the first frequency band and the second frequency band by the request frame. The transmission rate of communication using the first frequency band is smaller than the transmission rate of communication using the second frequency band,
When the first communication unit receives the permission frame in response to the request frame from the first wireless device, the first data frame transmitted by the first communication unit is transmitted by the second communication unit. The wireless device according to claim 8, wherein the wireless device has a smaller number of MAC frames than the second data frame. The transmission rate of communication using the first frequency band is smaller than the transmission rate of communication using the second frequency band,
The number of data frames transmitted by the first communication unit during the period reserved by the request frame when the first communication unit receives the permission frame in response to the request frame from the first wireless device The wireless device according to claim 8, wherein the number of data frames is smaller than the number of data frames transmitted by the second communication unit during a period reserved by the request frame. The transmission rate of communication using the first frequency band is smaller than the transmission rate of communication using the second frequency band,
Reserving the first frequency band described in the data frame transmitted by the first communication unit when the first communication unit receives the permission frame in response to the request frame from the first wireless device The radio apparatus according to claim 8, wherein a period during which the first frequency band described in a data frame transmitted by the second communication unit is reserved is longer. A first communication unit that communicates in the first frequency band, a second communication unit that communicates in the second frequency band, and a management unit that manages reservation states of the first frequency band and the second frequency band by other wireless devices A method of controlling a wireless device comprising:
When the first communication unit receives a frame that reserves the first frequency band for the first period, the management unit assumes that the first frequency band and the second frequency band are reserved for the first period. ,
When the second communication unit receives a frame that reserves the second frequency band for the second period, the management unit is configured to reserve the first frequency band and the second frequency band for the second period. A method for controlling a wireless device.

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