JP2016111587A - Radio communication device and radio communication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radio communication device that keeps a transmission right when a master unit is waiting for a response from a slave unit.SOLUTION: A radio communication device is a master unit that has master-slave relation with a plurality of slave stations and sequentially receives response frames responding to a broadcast data frame from the slave units. The radio communication device comprises: a radio reception unit for giving notice on receiving a response frame; a bandwidth securing frame creation unit for creating a bandwidth securing frame to be transmitted when a response frame is not received from a fist slave unit, in the case of not getting notice that a response frame has been received from the first slave unit at predetermined timing from the radio communication reception unit; and a radio transmission unit for transmitting the bandwidth securing frame input from the bandwidth securing frame creation unit by radio.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a wireless communication device that is a parent device and a wireless communication device that is a child device having a parent-child relationship with the parent device.

  When controlling an industrial device, a device called a master station notifies a plurality of devices called slave stations of the control amount of the industrial device, the slave station instructs the control amount notified to the industrial device, and the slave station sends a master station. It is common to repeatedly notify the state of industrial equipment. The time until data exchange between the master station and all slave stations is defined as cycle time. When the cycle time is short, it is possible to improve the production efficiency of industrial equipment. Further, since the control can be instructed finely when the cycle time is short, it is possible to improve the operation accuracy of the industrial equipment.

  Conventionally, in communication systems for industrial equipment, devices are connected by wire, but in recent years, expectations for wireless communication are increasing due to the ease of layout change and the demand for wire saving. Considering the convenience of users at the time of wireless communication, it is desirable to implement the wireless system in the ISM band, which is a frequency band that does not require a license. Among the ISM bands, IEEE 802.11 standard wireless LAN systems capable of high-speed communication are promising.

  By the way, there are two possible methods for transmitting data from the master station to the slave station. The first method is a method of individually transmitting data from a master station to a slave station. The second method is a method of broadcasting data from the master station to all slave stations. In the first method, the communication overhead is large and the cycle time becomes long, whereas in the second method, the communication overhead is small and the cycle time can be shortened. However, since there is generally no retransmission mechanism in broadcast transmission, it is necessary to provide a retransmission mechanism when using the second method.

  Patent Document 1 discloses a retransmission mechanism when the second method is used. The radio wave utilization type meter-reading device corresponds to the master station, and the radio wave utilization type gas meter corresponds to the slave station. If the radio wave type metering device transmits data to the radio wave type gas meter, and the radio wave type metering device does not receive response data from some radio wave type gas meters at the response timing, the radio wave type gas meter It is determined that data transmission to has failed. At this time, the radio wave utilization type meter-reading apparatus transmits the response timing together with the retransmission data to the radio wave utilization type gas meter. When the radio wave utilization type gas meter receives the retransmission data, it transmits the response data to the radio wave utilization type meter-reading device at the notified response timing.

JP 2001-36977 A

  However, in Patent Document 1, when a wireless LAN of the IEEE802.11 standard adopting CSMA / CA is used, nothing is transmitted at a response timing at which response data should be transmitted from a slave station in which data transmission has failed. Therefore, the transmission right may be acquired by another wireless LAN system. If the transmission right is acquired by another wireless LAN system, communication between the master station and the slave station cannot be performed, resulting in an increase in cycle time.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to obtain a wireless communication device that maintains a transmission right when a parent device is waiting for a response from a child device. Yes.

  A wireless communication device that is a parent device that has a parent-child relationship with a plurality of child devices and receives response frames in response to broadcast data frames in order from the child device, and notifies when a response frame is received And a bandwidth securing frame to be transmitted when no response frame is received from the first slave unit when the wireless communication receiver does not notify that the response frame has been received from the first slave unit at a predetermined timing. And a wireless transmission unit that wirelessly transmits a bandwidth reservation frame input from the bandwidth reservation frame generation unit.

  According to the present invention, it is possible to prevent an increase in cycle time due to an interrupt from another system when the parent device is waiting for a response from the child device.

1 is a block diagram showing a configuration of a radio communication system according to Embodiment 1. FIG. FIG. 2 is a block diagram illustrating a configuration of a wireless communication parent device according to Embodiment 1. 6 is a diagram illustrating an example of data held in a management table of a wireless communication parent device according to Embodiment 1. FIG. FIG. 3 is a block diagram illustrating a configuration of a wireless communication slave device according to the first embodiment. FIG. 3 shows communication between the wireless communication master device and the wireless communication slave device according to the first embodiment. FIG. 3 shows communication between the wireless communication master device and the wireless communication slave device according to the first embodiment. FIG. 3 shows a structure of a data frame transmitted by the wireless communication master device according to the first embodiment. 5 is a flowchart showing a processing flow of a data frame creation unit of the wireless communication master device according to the first embodiment. 4 is a flowchart showing a processing flow of a wireless reception unit of the wireless communication slave device according to the first embodiment. 5 is a flowchart showing a flow of processing of a response control unit of the wireless communication slave device according to the first embodiment. 4 is a flowchart showing a processing flow of a frame creation unit of the wireless communication slave device according to the first embodiment. 4 is a flowchart showing a processing flow of a wireless reception unit of the wireless communication master device according to the first embodiment. 4 is a flowchart showing a processing flow of a communication control unit of the wireless communication master device according to the first embodiment.

Embodiment 1 FIG.
First, the configuration of the wireless communication system will be described.
1 is a diagram illustrating a configuration of a radio communication system according to Embodiment 1. FIG. The wireless communication system includes a wireless communication master device 10 and wireless communication slave devices 11 to 13. The wireless communication master device 10 is a wireless communication device that is a master device. The wireless communication slave devices 11 to 13 are wireless communication devices that are slave devices. The wireless communication master device 10 and the wireless communication slave devices 11 to 13 have a parent-child relationship. A plurality of wireless communication slaves 11 to 13 are connected to one wireless communication parent device 10 wirelessly. The number of wireless communication slave units is not limited to the number shown in FIG.

The wireless communication master device 10 and the wireless communication slave devices 11 to 13 perform communication using CSMA / CA (Carrier Sense Multiple Access / Collection Avidance). In CSMA / CA, a transmitting device performs carrier sense in order to confirm whether another device is performing communication before transmission. If no carrier is detected, it is determined that another device is not communicating and is transmitted.
The wireless communication master device 10 broadcasts data to the wireless communication slave devices 11 to 13, and the wireless communication slave devices 11 to 13 transmit response data to the wireless communication master device 10.

Next, the configuration of the wireless communication master device 10 will be described.
FIG. 2 is a block diagram showing a configuration of radio communication master device 10 according to the first embodiment. The wireless communication base unit 10 includes a data generation unit 21, a communication control unit 22, a data frame creation unit 23, a bandwidth securing frame creation unit 24, a wireless transmission unit 25, a wireless reception unit 26, a wireless transfer determination unit 27, and a data processing unit 28. And a management table 29.

  The data generation unit 21 generates data to be transmitted to the wireless communication slave unit and outputs the data to the data frame creation unit 23. The communication control unit 22 calculates the transmission timing, and notifies the data frame creation unit 23 and the bandwidth reservation frame creation unit 24 of the transmission timing. The transmission timing is a timing at which the data frame is transmitted to the wireless communication slave units 11 to 13. The data frame creation unit 23 creates or updates response request information using information from the communication control unit 22 and information in the management table 29, creates a data frame, and outputs the data frame to the wireless transmission unit 25. The response request information is information indicating a wireless communication slave that requests a response. Further, the data frame creation unit 23 notifies the response request information to the bandwidth securing frame creation unit 24.

  The wireless transmission unit 25 wirelessly transmits the data frame input from the data frame creation unit 23 or the bandwidth reservation frame input from the bandwidth reservation frame creation unit 24. The bandwidth securing frame is a frame transmitted by the wireless communication master device 10 in order to secure a transmission right when a data frame is not received at a timing at which a response should be received from the wireless communication slave device.

  When receiving the response frame or the data frame from the wireless communication slaves 11 to 13, the wireless reception unit 26 outputs the response frame or data frame to the communication control unit 22 and the wireless transfer determination unit 27. The communication control unit 22 grasps from which wireless communication slave device the response is received based on the transmission source information of the response frame. The wireless transfer determination unit 27 determines whether or not to transfer the frame from the destination information of the frame notified from the wireless reception unit 26. When the destination information is the wireless communication slaves 11 to 13, the wireless transfer determination unit 27 outputs data to the data frame creation unit 23 and the data processing unit 28. The data processing unit 28 processes the transferred data. Further, the data processing unit 28 may output the processed data to another device. The management table 29 manages identification information, communication order information, and communication time information of the wireless communication slave units 11 to 13.

  FIG. 3 is a diagram illustrating an example of data held in the management table 29 of the wireless communication parent device 10 according to the first embodiment. The management table 29 manages the identifiers of the wireless communication slaves 11 to 13 in association with the communication order and the communication time. The contents of the management table 29 may be stored in advance in the internal memory, may be input from the outside of the wireless communication master unit 10, or may be input from the wireless communication slave units 11 to 13 or other not shown. You may make it receive from an apparatus.

Next, the configuration of the wireless communication slave unit 11 will be described. The wireless communication slave devices 12 to 13 have the same configuration as the wireless communication slave device 11.
FIG. 4 is a block diagram illustrating a configuration of the wireless communication slave device 11 according to the first embodiment. The wireless communication slave device 11 includes a wireless reception unit 31, a data processing unit 32, a response control unit 33, a data generation unit 34, a frame creation unit 35, a wireless transmission unit 36, and a management table 37.

  The wireless reception unit 31 determines whether the data frame received from the wireless communication master device 10 is a data frame that has already been received. In the case of a new data frame, the wireless reception unit 31 notifies the data processing unit 32 and the response control unit 33 of the received data frame data. The data processing unit 32 processes data. The response control unit 33 determines whether to respond from the response request information of the received data frame. When responding, the response control unit 33 calculates response timing. The response timing is a timing at which a response frame is transmitted to the wireless communication master unit 10.

The data generation unit 34 generates data to be transmitted to the wireless communication master unit 10. When data is input from the data generation unit 34, the frame creation unit 35 creates a data frame addressed to the wireless communication parent device 10 or another wireless communication child device via the wireless communication parent device 10. The data is output to the transmission unit 36.
In addition, the frame creation unit 35 creates a response frame for the data frame received from the wireless communication master device 10 using the information input from the response control unit 33 and outputs the response frame to the wireless transmission unit 36. The wireless transmission unit 36 wirelessly transmits the response frame to the wireless communication master unit 10.
The management table 37 holds a table similar to the management table 29 of the wireless communication master device 10, and manages the identifiers, communication order, and communication time of the wireless communication master device 10 and other communication slave devices in association with each other.

Next, a data frame transmitted by the wireless communication master device 10 will be described.
FIG. 5 is a diagram showing a configuration of the data frame 40 transmitted by the wireless communication master device 10 according to the first embodiment. The data frame 40 includes destination information 41, transmission source information 42, sequence number 43, response request information 44, and data 45. The destination information 41 is an identifier indicating the destination wireless communication device. When broadcast transmission is performed from the wireless communication master device 10, the destination information 41 becomes an identifier indicating all wireless communication slave devices. The transmission source information 42 is an identifier indicating the wireless communication device that is the transmission source. When transmitting from the wireless communication base unit 10, the transmission source information 42 is an identifier of the wireless communication base unit 10.

  The response request information 44 is information indicating a wireless communication slave that requests a response. In FIG. 5, the wireless communication slaves 11, 12, 13,... Are shown in order from the upper bit of the bitmap. When requesting a response from the wireless communication slaves 11, 12, 13, 1 is set in the upper 3 bits. The data frame creation unit 23 knows the association between the bit and the wireless communication slave unit, and sets 1 to the bit corresponding to the wireless communication slave unit that requests a response. Note that the method for associating the bit with the wireless communication slave is not particularly limited.

Next, the operation will be described.
First, a case where there is no radio error and no retransmission occurs in communication between the radio communication master device 10 and the radio communication slave devices 11 to 13 will be described.

  FIG. 6 is a diagram illustrating communication between the wireless communication master device 10 and the wireless communication slave devices 11 to 13 according to the first embodiment. In FIG. 6, time has passed from left to right.

  The wireless communication master device 10 broadcasts the data frame D0 to the wireless communication slave devices 11 to 13, and the wireless communication slave devices 11, 12, and 13 sequentially transmit response frames U1, U2, and U3 to the wireless communication master device 10. . T0 is the time taken to transmit the data frame D0. T1 is the response frame U1, T2 is the response frame U2, and T3 is the time taken to transmit the response frame U3.

  When receiving the data frame from the wireless communication master device 10, the wireless communication slave devices 11 to 13 wait for their transmission timing. When the transmission waiting time of the wireless communication slaves 11 to 13 ends and the transmission timing of the wireless communication slaves 11 to 13 arrives, carrier sense is performed for Δt time, and then a response frame is transmitted to the wireless communication parent device 10. Δt may be a SIFS (Short Interframe Space) time described in the IEEE 802.11 standard, or may be a shorter time. The transmission waiting time Tw (i) of the i-th wireless communication slave device is obtained by Equation 1.

However, i> 0. When i = 1, Tw (1) = 0. Tn is the data transmission time of the slave unit to be transmitted nth.
When the transmission waiting time Tw (i) ends, the i-th wireless communication slave device performs carrier sense. When the responses are received from all the wireless communication slaves 11 to 13 that have requested the response, the wireless communication master 10 updates the sequence number and transmits the next data.

  As described above, it can be confirmed whether or not data has arrived between the wireless communication master device 10 and the wireless communication slave devices 11 to 13. Therefore, data can be reliably transmitted between the wireless communication master device 10 and the wireless communication slave devices 11 to 13.

Next, an operation when the wireless communication slave unit 12 fails to receive a frame transmitted by the wireless communication master unit 10 will be described.
FIG. 7 is a diagram illustrating communication between the wireless communication master device 10 and the wireless communication slave devices 11 to 13 according to the first embodiment. In FIG. 7, time has passed from left to right.

  Data frames D0, Dx, and D2 are frames that are broadcast from the wireless communication master device 10 to the wireless communication slave devices 11 to 13. The response frame U1 is a frame transmitted from the wireless communication slave unit 11 to the wireless communication master unit 10. The response frame U2 is a frame transmitted from the wireless communication slave unit 12 to the wireless communication master unit 10. The response frame U3 is a frame transmitted from the wireless communication slave unit 13 to the wireless communication master unit 10.

  When the radio communication master unit 10 broadcasts the data frame D0 to the radio communication slave units 11 to 13, the radio communication slave units 11 and 13 successfully receive the data frame D0, but the radio communication slave unit 12 receives the data frame D0. Fails to receive. When the wireless communication slave device 11 finishes its own transmission waiting time, it performs carrier sense for Δt time, and then transmits a response frame U1 to the wireless communication master device 10. Next, since the wireless communication handset 12 has failed to receive the data frame D0, it does not transmit a response frame to the wireless communication base device 10.

  When the wireless communication master device 10 does not detect a carrier at the response reception determination timing, it determines that there is no response from the wireless communication slave device 12. The response reception determination timing is a timing at which the wireless communication master device 10 determines whether or not there is a response from the wireless communication slave device. In FIG. 7, the timing at which Δt + α has elapsed since the wireless communication master device 10 completed the reception of the response frame U1 is the response reception determination timing. The wireless communication master device 10 generates a band securing frame Dx and broadcasts it. The frame length of the bandwidth reservation frame Dx is T2-α. The frame length of the bandwidth securing frame Dx is set to such a length that the transmission is completed at the time when the transmission of the response frame is completed when the wireless communication handset 12 transmits the response frame.

  The wireless communication master device 10 assigns an identifier indicating that it is a bandwidth securing frame to the bandwidth securing frame Dx. All the data may be set to 0, or the next transmission time of the wireless communication parent device 10 or data addressed to the wireless communication child device 12 may be set. By transmitting the band securing frame Dx from the wireless communication master device 10, it is possible to prevent the cycle time from becoming long due to an interrupt from another system.

  Next, when the wireless communication slave device 13 finishes its own transmission waiting time, after performing carrier sense for Δt time, it transmits a response frame U3 to the wireless communication master device 10. After performing carrier sense for Δt time, the wireless communication master device 10 broadcasts a retransmission frame D2. After performing carrier sense for Δt time, the wireless communication slave device 12 transmits a response frame U2 to the wireless communication master device 10. Since the wireless communication slaves 11 and 13 have already received the data frame D0, they do nothing.

  Note that the i-th transmitting wireless communication slave does not transmit a response frame when carrier detection is performed and carrier detection continues even after the time of Δt + τ has elapsed. However, τ << Δt. As a result, it is possible to prevent the wireless communication slaves that are transmitted after the (i + 1) th time from being transmitted. Since the wireless communication master 10 does not receive a response frame from the i-th wireless communication slave, it performs retransmission.

  Next, detailed operations of the wireless communication master device 10 and the wireless communication slave devices 11 to 13 will be described.

First, an operation when the wireless communication master device 10 transmits data will be described.
FIG. 8 is a flowchart showing a process flow of the data frame creation unit 23 of the wireless communication master device 10 according to the first embodiment. Data generated from the data generation unit 21 before the data frame generation unit 23 starts processing is input. The data frame creation unit 23 starts processing in response to an input from the communication control unit 22.

  The data frame creation unit 23 is notified of response reception information of the data frame transmitted last time from the communication control unit 22 at the transmission timing. The response reception information is information indicating whether or not a response has been received from each wireless communication slave for the previously transmitted data frame. The response reception information may be bitmap information as with the response request information (step S81). The data frame creation unit 23 compares the response request information of the previously transmitted data frame held by itself with the response reception information notified from the communication control unit 22 (step S82).

  If they match, it means that the wireless communication master device 10 has received responses from all the wireless communication slave devices that have requested the response, and that all previous data frames have been successfully transmitted. The data frame creation unit 23 updates the held sequence number (step S83). The data frame creation unit 23 discards the created data frame that is held (step S84).

  The data frame creation unit 23 refers to the management table 29, generates response request information for a new data frame, and outputs it to the communication control unit 22 (step S85). The data frame creation unit 23 receives the identifier of the destination wireless communication slave unit, the identifier of the wireless communication master unit 10 itself, the stored sequence number, the response request information input from the communication control unit 22, and the input from the data generation unit 21. Set the recorded data and create a new data frame. The data frame creation unit 23 outputs the created data frame to the wireless transmission unit 25. The data frame creation unit 23 retains the generated response request information and data frame (step S86).

  In step S82, if the response request information of the previously transmitted data frame held by the data frame creation unit 23 does not match the response reception information notified from the communication control unit 22, the previous data frame transmission failed. It means that there is a wireless communication cordless handset. For each bit of the response request information, the data frame creation unit 23 updates the response request information with the bit matching the response reception information as 0. The wireless communication handset whose bit corresponds to 1 in the updated response request information is the wireless communication handset that failed to receive the previous data frame. By updating the response request information, it is possible to request a response to retransmission only to the wireless communication slave that failed to receive the previous data frame.

  The data frame creation unit 23 outputs the updated response request information to the communication control unit 22 (step S87). Further, the data frame creation unit 23 updates the response request information of the previously created data frame, outputs the data frame to the wireless transmission unit 25 (step S88), and ends the process.

  When a data frame is input from the data frame creation unit 23, the wireless transmission unit 25 adds a preamble, FCS (Frame Check Sequence), and the like to transmit wirelessly. FCS is a code for detecting data errors.

Next, an operation in which the wireless communication slave devices 11 to 13 receive a data frame from the wireless communication parent device 10 and transmit a response will be described.
FIG. 9 is a flowchart showing a process flow of the wireless reception unit 31 of the wireless communication slave device 11 according to the first embodiment. When receiving the data frame, the wireless reception unit 31 starts processing.

  The wireless reception unit 31 checks whether the FCS of the data frame is correct (step S91). If the FCS is correct, the wireless reception unit 31 compares the transmission source information of the received data frame with its own identifier (step S92). When the transmission source information 42 is different from its own identifier, the wireless reception unit 31 compares the sequence number of the received data frame with the held sequence number (step S93). If the sequence numbers are different, the wireless reception unit 31 updates the held sequence number to the sequence number of the received data frame (step S94). The wireless reception unit 31 outputs the received data frame data to the data processing unit 32 (step S95). The wireless reception unit 31 outputs the received data frame sequence number and response request information to the response control unit 33 (step S96), and ends the process.

In step S93, if the sequence number of the received data frame is the same as the stored sequence number, it is already received data, so the wireless reception unit 31 does not output data to the data processing unit 32, and the processing is step Proceed to S96.
In step S91, when the FCS of the data frame is not correct, the wireless reception unit 31 discards the data frame (step S97) and ends the process. In step S92, when the transmission source information of the data frame received by the wireless reception unit 31 is the same as its own identification information, the wireless reception unit 31 discards the data frame (step S97) and ends the process.

Next, an operation for calculating a response timing, which is a timing at which the wireless communication slave device 11 responds, will be described.
FIG. 10 is a flowchart showing a process flow of the response control unit 33 of the wireless communication slave device 11 according to the first embodiment. The response control unit 33 starts processing when response request information is input from the wireless reception unit 31.

  The response control unit 33 confirms the bitmap of the response request information (Step S101). When the bit indicating itself is 1, the response control unit 33 calculates the response timing from the bitmap of the response request information and the information in the management table 37. The response control unit 33 can grasp to which wireless communication handset the data frame is transmitted from the bitmap of the response request information. In addition, the response control unit 33 acquires the communication order and communication time for each wireless communication slave that transmits a response request from the management table 37. The response timing for transmitting the response frame is calculated from the information and the time Δt required for carrier sense (step S102). The response control unit 33 outputs the sequence number input from the wireless reception unit 31 to the frame creation unit 35 at the calculated response timing (step S103), and ends the process.

Next, an operation in which the wireless communication handset 11 creates a response frame will be described.
FIG. 11 is a flowchart showing a process flow of the frame creation unit 35 of the wireless communication slave device 11 according to the first embodiment. The frame creation unit 35 starts processing when the sequence number is input from the response control unit 33.

  The frame creation unit 35 compares the sequence number input from the response control unit 33 with the held sequence number (step S111). If the sequence numbers are different, the frame creation unit 35 updates the held sequence number to the sequence number notified from the response control unit 33 (step S112). Further, the frame creation unit 35 discards the created response frame transmitted last time (step S113). The frame creation unit 35 creates a new response frame and outputs it to the wireless transmission unit 36 (step S114), and ends the process.

  In step S111, when the sequence number input from the response control unit 33 and the held sequence number are the same, the wireless communication slave unit 11 has transmitted the previous response frame, but the wireless communication master unit 10 has received the response frame. This is a failed case. In order to retransmit the previously created response frame, the frame creation unit 35 outputs the created response frame to the wireless transmission unit 36 (step S115), and ends the process.

  The wireless transmission unit 36 wirelessly transmits a response frame input from the frame creation unit 35 with a preamble or FCS.

Next, processing in which the wireless communication master device 10 receives a response frame from the wireless communication slave device 11 will be described.
FIG. 12 is a flowchart showing a process flow of the wireless reception unit 26 of the wireless communication master device 10 according to the first embodiment. The wireless reception unit 26 starts processing for detecting a carrier.

  The wireless receiving unit 26 notifies the communication control unit 22 that a carrier is detected (step S121). When receiving the response frame, the wireless reception unit 26 checks whether the FCS is correct (step S122). If the FCS is correct, the management table 29 is referred to (step S123). When the transmission source information of the received response frame exists in the management table 29, the wireless reception unit 26 outputs the destination information and data of the received response frame to the wireless transfer determination unit 27 (step S124). Further, the transmission source information is output to the communication control unit 22 (step S125), and the process is terminated.

  If the FCS is not correct in step S122, the process ends. If the source information of the received response frame does not exist in the management table 29 in step S123, the process ends.

Next, processing in which the wireless communication master device 10 transmits a bandwidth securing frame will be described.
FIG. 13 is a flowchart showing a process flow of the communication control unit 22 of the wireless communication master device 10 according to the first embodiment. The communication control unit 22 starts processing when response request information is input from the data frame creation unit 23.

  The communication control unit 22 calculates a response reception determination timing and a response reception completion timing from the response request information input from the data frame creation unit 23 and the communication time of the wireless communication slave unit saved in the management table 29. The response reception completion timing is the timing at which reception of response frames is completed from all the wireless communication slave devices that transmit responses (step S131). Let N be the sum of the numbers in the response request information bitmap. The wireless communication master device 10 should receive response frames from the N wireless communication slave devices, and determines whether the processes of steps S133 to 135 have been performed N times (step S132). If not implemented N times, the communication control unit 22 determines whether the wireless reception unit 26 is notified that the carrier is detected at the response reception determination timing (step S133).

  When notified that the carrier is detected, the process returns to step S132, and the communication control unit 22 waits until the next response reception determination timing. If not notified, the communication control unit 22 calculates the frame length of the bandwidth reservation frame and outputs it to the bandwidth reservation frame creation unit 24. For example, in the case of FIG. 6, the frame length of the bandwidth securing frame is T2-α. Further, the communication control unit 22 outputs the response request information input from the data frame creation unit 23 to the bandwidth reservation frame creation unit 24. (Step S134).

  I indicating the number of times of performing steps S133 to 135 is incremented (step S135), and the process returns to step S132. When the processes of steps S133 to S135 are performed N times, the communication control unit 22 generates response reception information at the response reception completion timing. The communication control unit 22 generates response reception information in the same format as the response request information. The communication control unit 22 notifies the data frame creation unit 23 of the response reception information (step S136) and ends the process.

  The bandwidth reservation frame creation unit 24 creates a bandwidth reservation frame from the frame length and response request information input from the communication control unit 22 and outputs the bandwidth reservation frame to the wireless transmission unit 25. The wireless transmission unit 25 wirelessly transmits the bandwidth reservation frame input from the bandwidth reservation frame creation unit 24.

When the wireless communication slave unit transmits data to another wireless communication slave device, the data is transmitted via the wireless communication master device 10. The operation will be described using an example in which data is transmitted from the wireless communication handset 11 to the wireless communication handset 12.
The data generation unit 34 of the wireless communication slave unit 11 generates data and inputs it to the frame generation unit 35. The frame creation unit 35 sets the wireless communication slave unit 12 in the destination information, creates a data frame in which the data input from the data generation unit 34 is set, and outputs the data frame to the wireless transmission unit 36. The wireless transmission unit 36 wirelessly transmits a data frame input from the frame creation unit 35 with a preamble, FCS, or the like.

  The wireless reception unit 26 of the wireless communication base unit 10 performs the processing of steps S121 to S124 in FIG. 12 and outputs the destination information and data of the received data frame to the wireless transfer processing unit 27. The wireless transfer processing unit 27 outputs the destination information to the communication control unit 22 because the destination information does not match its own identification information. Further, the wireless transfer processing unit 27 outputs the data to the data frame creation unit 23. In response to an instruction from the communication control unit 22, the data frame creation unit 23 sets the wireless communication slave 12 as destination information, creates a data frame in which data input from the wireless transfer processing unit 27 is set, and creates a wireless transmission unit. To 36. The wireless transmission unit 36 wirelessly transmits a data frame input from the frame creation unit 35 with a preamble, FCS, or the like.

  In this embodiment, the frame length of the bandwidth reservation frame calculated by the communication control unit 22 is input to the bandwidth reservation frame creation unit 24. The bandwidth reservation frame creation unit 24 uses the frame length held by the bandwidth reservation frame creation unit 24. A reserved frame may be created. When the time from the response reception determination timing to the time when the response frame should be transmitted is always the same, the same frame length may be used. In this way, the communication control unit 22 does not need to calculate the frame length.

Further, even when the time from the response reception determination timing to the completion of transmission of the response frame changes, the bandwidth securing frame creation unit 24 may hold the frame length according to the shortest time. Even when the frame length is short, the transmission of the bandwidth reservation frame is less likely to be acquired by another system than when the bandwidth reservation frame is not transmitted. Therefore, the transmission right can be held.
Further, the management table 29 may hold the frame lengths of the bandwidth securing frames corresponding to the wireless communication slaves 11 to 13 respectively. The bandwidth securing frame creation unit 24 refers to the management table 29 and creates a bandwidth securing frame with a frame length corresponding to the wireless communication slave that is the destination of the bandwidth securing frame.

  Further, the data generation unit 21 and the data processing unit 28 of the wireless communication master device 10 may be provided in other devices, and the wireless communication master device 10 and other devices may be connected by wire. Similarly, the data generation unit 34 and the data processing unit 32 of the wireless communication slaves 11 to 13 may be provided in other devices, and the wireless communication slaves 11 to 13 and the other devices may be connected by wire. .

  Therefore, in the present embodiment, a wireless communication device is a parent device that has a parent-child relationship with a plurality of child devices and receives response frames in response to broadcast data frames in order from the child devices, A wireless reception unit that notifies when a frame is received, a communication control unit that outputs a frame length when the wireless communication reception unit does not notify that a response frame has been received at a predetermined timing, and a first control unit A bandwidth reservation frame creation unit for creating a bandwidth reservation frame to be transmitted when a response frame is not received from the slave unit with a frame length input from the communication control unit, and a bandwidth reservation frame input from the bandwidth reservation frame creation unit. And a wireless transmission unit that transmits wirelessly, the transmission right can be held when the parent device is waiting for a response from the child device. Therefore, it is possible to prevent the cycle time from being increased by preventing the transmission right from being acquired by another system using the same band and keeping the transmission right.

  Further, based on the time when transmission of the response frame from the first slave unit should be completed when the wireless communication receiver does not notify that the response frame has been received from the first slave unit at a predetermined timing. A communication control unit that calculates the frame length is provided, and the bandwidth securing frame creation unit creates a bandwidth securing frame with the frame length calculated by the communication control unit, so the bandwidth matched to the length of the response frame that should have been received A reserved frame can be transmitted. Therefore, it is possible to prevent the cycle time from being increased by preventing the transmission right from being acquired by another system using the same band and keeping the transmission right.

  In addition, a wireless communication device that is a child device having a parent-child relationship with the parent device, a wireless reception unit that notifies that a data frame is received from the parent device, and a response frame that responds to the data frame notified from the wireless reception unit When transmitting, a response control unit that calculates the transmission timing of transmitting the response frame based on the order of transmission of the local communication device among the slave units that transmit the response frame, and instructs the creation of the response frame when the transmission timing comes And a frame creation unit that creates a response frame when instructed by the response control unit, and a wireless transmission unit that wirelessly transmits the response frame. Therefore, when a plurality of slave units transmit response frames, The machine can send response frames in order. Therefore, the cycle time can be prevented from increasing, and the response frames transmitted by the slave units can be prevented from colliding.

DESCRIPTION OF SYMBOLS 10 Wireless communication main | base station 11-13 Wireless communication subunit | mobile_unit 21, 34 Data generation part 22 Communication control part 23 Data frame creation part 24 Band reservation frame creation part 25, 36 Wireless transmission part 26, 31 Wireless reception part 27 Wireless transfer determination part 28, 32 Data processing units 29, 37 Management table 33 Response control unit 35 Frame creation unit 40 Data frame 41 Destination information 42 Source information 43 Sequence number 44 Response request information 45 Data

Claims (11)

A wireless communication device that has a parent-child relationship with a plurality of child devices, and is a parent device that sequentially receives response frames from the child devices in response to the data frames that are broadcast.
A wireless receiver for notifying that the response frame is received;
When the wireless communication receiver does not notify that the response frame has been received from the first handset at a predetermined timing,
A bandwidth securing frame creation unit that creates a bandwidth securing frame to be transmitted when the response frame is not received from the first slave unit;
A wireless transmission unit that wirelessly transmits the bandwidth reservation frame input from the bandwidth reservation frame creation unit;
A wireless communication device comprising: Based on the time when transmission of the response frame from the first slave unit should be completed when the wireless communication receiver does not notify that the response frame has been received from the first slave unit at the timing A communication control unit for calculating the frame length;
The wireless communication device according to claim 1, wherein the bandwidth securing frame creation unit creates the bandwidth securing frame with the frame length calculated by the communication control unit.   The communication control unit is configured to perform carrier sense in which the slave unit confirms the order in which the slave unit that has requested a response to the data frame transmits the response frame, the time required for transmission, and whether or not the bandwidth to be used is free. 3. The wireless communication device according to claim 1, wherein a timing at which the response frame is received from the first slave unit is calculated based on a time required for the first slave unit. A data frame creation unit for creating the data frame;
The communication control unit generates response request information indicating a slave unit that requests a response to the data frame,
The radio frame creation unit adds the response request information and a sequence number for identifying the data frame to the data frame,
4. The wireless communication device according to claim 1, wherein the wireless transmission unit broadcasts the data frame created by the data frame creation unit. 5. Whether the communication control unit has received the response frame from the slave unit at a response reception completion timing that should complete reception of the response frame from all the slave units that have requested a response to the first data frame. Output response reception information indicating whether or not to the radio frame creation unit,
The radio frame creation unit, when there is a slave unit that has not received the response frame from the response request information and the response reception information input from the communication control unit, a response request that requests a response to the slave unit The wireless communication device according to any one of claims 1 to 4, wherein information is set in a previously created data frame and retransmitted by broadcast transmission.   The radio frame creation unit compares the response request information added to the previously created radio frame with the response reception information, and if there is no slave unit that has not received the response frame, creates a new data frame, The wireless communication device according to claim 5, wherein the wireless communication device outputs the wireless transmission unit.   The communication control unit calculates the response reception completion timing based on a time required for transmission of the response frame by a slave unit that has requested a response to the data frame and a time required for the carrier sense. The wireless communication device according to claim 5 or 6.   8. The communication control unit according to claim 4, wherein the communication control unit creates the response request information as a bitmap, assigns a slave to each bit, and sets whether to request transmission of the response frame. The wireless communication device according to any one of the above. A wireless communication device that is a child device having a parent-child relationship with the parent device,
A wireless receiver for notifying that a data frame is received from the master unit;
When transmitting a response frame in response to the data frame notified from the wireless receiver, a transmission timing for transmitting the response frame based on an order in which the local communication device transmits among the slave devices transmitting the response frame A response control unit for instructing creation of the response frame when the transmission timing is reached,
A frame creation unit that creates the response frame when the instruction is received from the response control unit;
A wireless transmission unit for wirelessly transmitting the response frame;
A wireless communication device comprising:   The wireless communication device according to claim 10, wherein the response control unit outputs a previously created response frame to the wireless transmission unit when receiving a data frame that has already been received again. A wireless communication method for a parent device that has a parent-child relationship with a plurality of child devices and receives response frames in response to the data frames transmitted in the broadcast from the child devices in order,
A radio reception step for notifying that the response frame is received;
A bandwidth securing frame that creates a bandwidth securing frame to be transmitted when the response frame is not received from the first slave when the response is not received from the first slave at a predetermined timing. Creation steps,
A wireless transmission step of wirelessly transmitting the bandwidth reservation frame;
A wireless communication method comprising:

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