JP6221060B2 - Wireless device - Google Patents

Description

  The present invention relates to wireless communication when collecting meter reading data from a meter by wireless communication.

  When transmitting meter reading data such as gas collected by a smart meter installed in each home to a data management center such as a gas company, a wireless slave unit built in the smart meter and a wireless device such as a utility pole or the roof of a building An OMS (Open Metering System) protocol operating on a Wireless M-bus for wireless communication with a base unit is being studied mainly in Europe. The wireless master unit and a data management center such as a gas company are connected using a public network such as the Internet.

  In the OMS protocol, a method in which a wireless slave device periodically transmits meter reading data to the wireless master device is used. According to the method, the wireless slave unit periodically turns on the power of the wireless unit and transmits meter reading data every six hours, for example, and then waits for data reception from the wireless master unit. After the communication is completed, the wireless unit is turned off and enters a standby state, so only a short communication occurs once every 6 hours, power consumption can be reduced, and the battery can operate for more than 10 years. Yes. On the other hand, when it is desired to transmit some data from the wireless master device side to the wireless slave device side, the wireless slave device waits until the next timing for transmitting meter reading data.

  Here, a case where a large amount of data is transmitted from a wireless master device to a plurality of wireless slave devices will be described. The large-capacity data is, for example, rewrite data of the firmware of the wireless slave unit. When transmitting such large-capacity data common to each wireless slave device, it is inefficient to transmit from the wireless master device for each wireless slave device at the meter reading data transmission timing of each wireless slave device. Therefore, at the meter reading data transmission timing of each wireless slave device, the wireless master device transmits reception time designation information for receiving large-capacity data to each wireless slave device. All the wireless slaves are in a reception state at the designated reception time and wait for large-capacity transmission data from the wireless master. Normally, in the reception state, the power of the wireless reception unit is always turned on, and the continuous reception state is maintained until the transmission of large-capacity transmission data. However, in the OMS protocol, it cannot be said that the time synchronization between the wireless master device and each wireless slave device is sufficient, and a time lag of about ± 5 seconds is considered sufficiently. Therefore, it is necessary for the wireless master device to transmit a large amount of data with a delay of 5 seconds or more from the designated reception time. The wireless slave unit waits for at least 10 seconds until receiving a large capacity after it enters the reception state, and wastes power and affects the battery life. Therefore, a method using an intermittent reception method as shown in Patent Document 1 can be considered.

  According to Patent Document 1, the wireless master device repeatedly transmits a Wake Up frame continuously. The time for repeated transmission is longer than the intermittent reception cycle of each wireless slave unit. The Wake Up frame includes time information for transmitting broadcast data. As another example, in Patent Document 1 described above, for the purpose of reducing the number of repetitions of repeatedly transmitting a Wake Up frame, that is, for the purpose of shortening the transmission time, the wireless master device estimates and stores the intermittent reception timing of each wireless slave device. In addition, it is described that a Wake Up frame is repeatedly transmitted a predetermined number of times in accordance with the intermittent reception timing stored and estimated.

JP2013-078009A

  However, in the method according to Patent Document 1, a Wake Up frame must be transmitted continuously and repeatedly. However, in the OMS protocol, a transmission pause time of a predetermined time is required after a certain frame is transmitted. It is not allowed to do. Further, as described above, there is a problem that the time difference between the wireless master device and the wireless slave device is large, and the wireless master device cannot estimate the intermittent reception timing of each wireless slave device.

  The present invention solves the above-described conventional problems, and allows a wireless slave device to receive large-capacity data from a wireless master device while preventing an increase in power consumption with a simple configuration without significantly changing the OMS protocol. An object is to provide a receiving apparatus.

  In order to solve the above-described conventional problem, the wireless device according to the present invention performs wireless communication with a transmitting device that transmits a second signal after a predetermined time since transmission of the first signal, and a signal transmitted from the transmitting device. Carrier sensing that is realized by capturing the reception level of the signal is intermittently performed, the presence or absence of a signal is detected according to the reception level of the signal, and the presence of the first signal is detected by carrier sensing, and the carrier is performed a predetermined number of times. If the presence of the signal cannot be detected in the sense, the receiving operation for receiving the second signal is started.

  As a result, the wireless slave device can receive a large amount of data from the wireless master device while preventing an increase in power consumption with a simple configuration.

  By using the receiving apparatus of the present invention, in a wireless communication system such as an automatic gas meter reading system, large-capacity data such as firmware is wirelessly transmitted to each wireless slave unit without greatly losing power consumption of each wireless device. The master unit can broadcast simultaneously.

The block diagram of the receiver in 1st embodiment of this invention Frame configuration diagram of OMS protocol in the first embodiment of the present invention (1) The figure which shows the structure of the periodic meter-reading data communication area | region and broadcast communication area | region in 1st embodiment of this invention (2) The periodical meter-reading data communication area | region and broadcast communication in 1st embodiment of this invention Diagram showing the detailed configuration of the area The figure which shows the communication sequence of the periodic meter-reading data by the OMS protocol in 1st embodiment of this invention. The figure which shows the communication sequence of the simultaneous broadcast from the wireless main | base station by the OMS protocol in 1st embodiment of this invention. The figure explaining the reception operation | movement of the radio | wireless subunit | mobile_unit which receives the simultaneous broadcast data from the radio | wireless parent | base station in 1st embodiment of this invention.

  1st invention is a radio | wireless apparatus which carries out radio | wireless communication with the transmission apparatus which transmits a 2nd signal in predetermined time after finishing transmitting a 1st signal, Comprising: The reception level of the signal transmitted from a transmission apparatus is caught. The carrier sense that is performed intermittently and detects the presence or absence of a signal according to the reception level of the signal, and the carrier sense that is performed a predetermined number of times after the carrier sense unit detects the presence of the first signal If the presence of the signal cannot be detected in step 1, a receiving unit for starting a receiving operation for receiving the second signal is provided.

According to this, the wireless device (corresponding to the wireless slave device) can receive a large amount of data from the transmitting device (corresponding to the wireless master device) while preventing an increase in power consumption with a simple configuration.

  In particular, in the first invention, the second invention includes an intermittent control unit that controls an intermittent interval of carrier sense by the carrier sense unit, and the intermittent control unit detects the presence of the first signal when the carrier sense unit detects the presence of the first signal. The intermittent interval of the carrier sense, which was T1, is changed to T2 according to the period T5 from when the first signal is transmitted until the second signal is transmitted.

  According to this, it is possible to set the intermittent interval T2 optimized for the interval between the first signal and the second signal, it is possible to prevent a reception error of the second signal and to prevent an increase in power consumption.

  In particular, according to a third aspect, in the second aspect, the carrier sense unit stops the carrier sense operation and shifts to a standby state when the first signal cannot be detected within a predetermined time.

  According to this, even if it is not possible to receive the broadcast data of the wireless master unit, it is possible to return to the standby state after a predetermined time has elapsed, and it is possible to prevent battery consumption.

  In a fourth aspect of the invention, in particular, in the second aspect of the invention, the carrier sense unit determines that the first signal is detected continuously or when the first signal is detected a predetermined number of times within a predetermined time.

  According to this, it is possible to accurately identify whether the signal from the radio base unit or carrier detection due to noise is detected, and erroneous detection due to noise can be prevented.

  In a fifth aspect of the invention, in particular, in the second aspect of the invention, the carrier sense unit stops the carrier sense operation and shifts to a standby state when the second signal cannot be detected within a predetermined time.

  According to this, even if carrier detection is mistaken due to noise, it is possible to return to the standby state after a predetermined time has elapsed, and it is possible to prevent battery consumption.

  6th invention is a communication system which consists of a transmitter and a radio | wireless apparatus which performs radio | wireless communication between transmitters, Comprising: A transmitter is a 2nd signal after predetermined time after finishing transmitting a 1st signal. The reception device intermittently performs carrier sense realized by capturing the reception level of the signal transmitted from the transmission device, and detects the presence or absence of the signal according to the reception level of the signal. And a receiving unit that starts a receiving operation for receiving the second signal if the presence of the signal cannot be detected in the carrier sensing performed a predetermined number of times after the carrier sensing unit detects the presence of the first signal. Are provided.

  According to this, the receiving device (corresponding to the wireless slave device) can receive large-capacity data from the transmitting device (corresponding to the wireless master device) while preventing an increase in power consumption with a simple configuration.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
A first embodiment of the present invention will be described. FIG. 1 is a block diagram showing an example of a periodic notification device according to the present invention.

First, the configuration and operation of the periodic notification device will be described with reference to FIG. First, an outline of the periodic transmission operation will be described. As will be described in detail later, the control means 8 turns on the power of the transmission means 9 at a predetermined interval Ts. When the power is turned on by the control means 8, the transmission means 9 transmits meter reading data as radio waves via the antenna 1. When the transmission of meter reading data is completed, the control means 8 turns off the power of the transmission means, operates the signal reception means 5 for a predetermined time, and checks whether there is a signal to be received by the antenna 1.

  Next, an outline of a broadcast receiving operation described later will be described. The signal input to the antenna 1 is selectively amplified by the selective amplification means 2 at a desired frequency. The control means 8 is involved in the control of the entire periodic notification device shown in FIG. 1, and activates the intermittent control means 3 at a predetermined time. When the intermittent control means 3 is activated, the intermittent control means 3 performs ON / OFF control of the power sources of the carrier sense means 4 and the selective amplification means 2 at predetermined intervals. That is, the carrier sensing means 4 is caused to perform a carrier sensing operation intermittently at a predetermined interval. The first determination unit 6 is activated by the control unit 8 and determines whether the carrier sense unit 4 has detected a carrier. When it is determined that the carrier has been detected, the first determination unit 6 notifies the control unit 8 of carrier detection information. . The second determination means 7 is activated by the control means 8 to determine whether the carrier sense means 4 detects no carrier. When it is determined that no carrier is detected, the control means 8 is notified of no carrier detection information. To do. The control means 8 activates the signal reception means 5 based on the carrier detection information from the first determination means 6 and the carrier non-information from the second determination means 7 and performs a signal reception decoding operation.

  FIG. 2 is a diagram showing a data frame configuration conforming to the OMS protocol transmitted from the wireless master device. The preamble 21 is composed of a 16-bit bit string in which 0 and 1 are repeated. The synchronization signal 22 is composed of 16 bits and is a bit string for identifying the head of the data 23 transmitted following the synchronization signal 22. The data 23 is a bit string composed of communication control information such as a transmission source address and a transmission destination address and application data, and data of a maximum of 2048 bits can be transmitted in the OMS protocol. The preamble 21 is used to create a data sampling timing for identifying whether the received signal is 1 or 0.

  FIG. 3 is a diagram showing the configuration of the periodic meter reading data communication area and the broadcast communication area. The 24 hours a day is divided into four equal zones, A, B, C, and D every Ts = 6 hours ((1) in FIG. 3). Each zone is further divided into n equal parts at each time interval Tc, and each area Tc divided into n parts is assigned to an area where each wireless handset calls periodic meter reading data. In the example of (2) in FIG. 3, Ts = 6 hours divided into four equal parts is divided into 400 parts every Tc = 54 seconds. The first Tc1 is the calling area of the first wireless handset 1, the next Tc2 is the calling area of the second wireless handset 2, the Tc3 is the calling area of the third wireless handset 3, and so on. Each area Tcn is assigned to the calling area of each wireless slave device n. In the example of (2) in FIG. 3, a calling area can be assigned to 400 wireless slave units. Each wireless slave unit wirelessly transmits the periodic meter reading data to the wireless master unit in its call area. In the example of FIG. 3, each wireless slave unit makes a call in its own area in each of zones A, B, C, and D. Therefore, the periodic meter reading data is transmitted four times a day for each wireless slave unit. However, since it is not necessary to transmit the periodic meter reading data four times a day, if the periodic meter reading data is transmitted three times a day, the wireless device is set so that the transmission in the next zone is paused once. The machine is structured. That is, in the zones A, B, and C, each wireless slave unit issues periodic meter reading data, and in the zone D, the periodic meter reading data is not transmitted. Then, the zone D in which the wireless slave unit does not make a call for periodic meter-reading data is used as an area for transmitting a large volume from the wireless master unit. As described above, large-capacity transmission data from the wireless master device includes, for example, rewrite data of the firmware of the wireless slave device.

As described above, after each wireless handset makes a call for periodic meter reading a plurality of times, it is configured to pause the next call timing, so that a predetermined set of periodic meter reading and calling suspension periods ( In the example of FIG. 3, since zone D) can be secured, large-capacity data can be transmitted from the wireless master device in zone D, which is the suspension period. Firmware rewrite data is as large as 500 kbytes, for example. On the other hand, when M-BUS is used, the transmission speed is as low as 2400 bps.
It takes almost an hour. Therefore, a collective time domain as indicated by zone D is required.

  A communication sequence in which the wireless slave unit calls periodic meter-reading data will be described with reference to FIG. FIG. 4 shows a periodic meter reading data calling sequence from the wireless slave unit based on the OMS protocol. M1 is the first wireless slave device 1, M2 is the second wireless slave device 2, and Mn is the nth wireless slave device n. C is a wireless master unit. The wireless slave device M1 transmits a message SND-NR to the wireless master device C at the head of the area Tc1 in the zone A shown in FIG. Periodic meter reading data is on the SND-NR message. If there is no data to be transmitted to the wireless slave device M1 that has transmitted the periodic meter reading data, the wireless master device C that has received the SND-NR message transmits SND-NKE, which is a link disconnection request, and ends the communication. Next, the wireless slave device M2 transmits a message SND-NR to the wireless master device C at the head of the area Tc2 in the zone A shown in FIG. Periodic meter reading data is on the SND-NR message. If there is no data to be transmitted to the wireless slave device M1 that has transmitted the periodic meter reading data, the wireless master device C that has received the SND-NR message transmits SND-NKE, which is a link disconnection request, and ends the communication. The wireless slave device n transmits a message called SND-NR to the wireless master device C at the head of the area Tcn in the zone A shown in FIG. Periodic meter reading data is on the SND-NR message. If there is no data to be transmitted to the wireless slave device M1 that has transmitted the periodic meter reading data, the wireless master device C that has received the SND-NR message transmits SND-NKE, which is a link disconnection request, and ends the communication. Similarly, each wireless slave unit performs the same operation as in zone A in zones B and C. In zone D, all the wireless slave units stop transmitting SND-NR messages. That is, when each wireless slave unit transmits the SND-NR message three times at the time interval Ts, it stops the transmission of the SND-NR message at the transmission timing A at the next time interval Ts.

  When there is data to be transmitted to the wireless slave device M1 from which the wireless master device C has transmitted the periodic meter reading data, an SND-UD message is transmitted. The wireless slave device M1 that has received the SND-UD message transmits an ACK message, and the wireless master device C transmits SND-NKE, which is a link disconnection request, and ends the communication. When the wireless master device C wants to rewrite the firmware of each wireless slave device, it takes nearly one hour to transmit the firmware data. Therefore, the SND- transmitted at the periodic meter reading data call timing of the wireless slave device M1 shown in FIG. It is impossible in terms of time to transmit the firmware data by the SND-UD message after NR. Because the time length of the periodic meter reading data call timing of the wireless slave unit M1 is only 54 seconds at the maximum as shown in FIG. 3 (2), when the firmware data is transmitted in this time region, the next wireless slave unit M2 Since the meter reading data is called, the firmware data transmission from the wireless master unit and the periodic meter reading data from the wireless slave unit M2 collide, and the system becomes unstable. Accordingly, when the wireless master device C wants to rewrite the firmware of each wireless slave device, the wireless master device C transmits an SND-UD message transmitted after the SND-NR of the periodic meter reading data call to each wireless slave device. The information of the time Ta is put so as to start reception at a predetermined reception timing B in the zone D area. As described above, using the SND-UD message after the SND-NR message on which the periodic meter reading data from each wireless slave device transmitted in the zone A, B or C is used, the wireless master device C is in the zone D. Each wireless slave unit can be instructed to start reception at a predetermined timing B. Note that information indicating the elapsed time until reception is started can be used instead of the time Ta.

FIG. 5 is a diagram showing a communication sequence in zone D shown in FIG. When the time Ta which is the reception timing B instructed by the wireless master device C described above is reached, each wireless slave device is in a reception state after transmitting the SND-NR. In the OMS protocol, there is no synchronization signal periodically transmitted from the wireless master device as disclosed in Patent Document 1. Clock synchronization between the wireless master device and the wireless slave device is performed by the wireless master device receiving the time information of the wireless slave device included in the SND-NR message, checking the error from the clock of the wireless master device, When this occurs, the time information is transmitted to the target wireless slave device using the SND-UD message. Then, time synchronization between the wireless slave unit and the wireless master unit is not performed until a predetermined time error occurs so that time information is not frequently communicated. Therefore, in the OMS protocol, the clocks of the wireless master device C and the wireless slave devices M1 to Mn are not exactly the same, and an error of about ± 5 seconds occurs. For example, in the example shown in FIG. 5, the timepiece progresses in the order of the wireless slave device M1, the wireless slave device M2, and the wireless slave device Mn in the order of the wireless slave device M1. Then, the wireless master device C transmits SND-UD1 carrying firmware rewrite data at time Tb. The time Tb is set to a time delayed by 10 seconds from the time Ta in consideration of the maximum clock error between the wireless master device C and each of the wireless slave devices M1 to Mn. Therefore, at the time Tb, all the wireless slave units instructed to receive are in the receiving state. Telegrams such as SND-NR and SND-UD have the frame configuration shown in FIG. 2, and periodic meter reading data and firmware rewrite data are on the data section 23. In the OMS protocol, the data portion 23 has a maximum of 2048 bits. On the other hand, the firmware rewrite data is as large as 500 kbytes. Therefore, since it is not possible to send all the firmware rewrite data only by SND-UD1, the firmware rewrite data is divided into small data of 2048 bits or less, and SND-UD1, SND-UD2,... SND-UDn and a plurality of messages are transmitted separately. Finally, SND-NKE, which is a link disconnection request, is transmitted and communication is terminated. The messages of SND-UD1 to SND-UDn and SND-NKE transmitted by the wireless master device C are received by all the wireless slave devices M1 to Mn in the receiving state.

  In FIG. 5, the wireless slave unit transmits the SND-NR before entering the reception state. This is based on the OMS protocol, but the frequency transmitted by the wireless slave devices M1 to Mn and the frequency transmitted by the wireless master device C, that is, the frequencies received by the wireless slave devices M1 to Mn may be different. In the same case, it is conceivable that the SND-NR transmitted by the wireless slave device M2 is detected by the wireless slave device M1 that is already in the reception state. When the frequency transmitted by the wireless slave devices M1 to Mn is the same as the received frequency, the wireless slave devices M1 to Mn are considered to have transmitted without actually transmitting the SND-NR, and are configured to be in a reception state. That's fine. With such a configuration, the SND-NR transmitted by another wireless slave device is not erroneously detected as a signal from the wireless master device.

FIG. 6 is a diagram for explaining the reception operation at the reception timing B of the sound D of the wireless slave devices M1 to M, that is, the time Ta. In FIG. 6, M1_RX indicates the reception operation of the wireless slave device M1, M2_RX indicates the reception operation of the wireless slave device M2, and Mn_RX indicates the reception operation of the wireless slave device Mn. The wireless slave device M1 assumes that the SND-NR is transmitted at the time Ta and is in a reception state. The wireless slave device M2 enters the reception state after the time Ta, and the wireless slave device Mn enters the reception state after the time Ta by T3. If the maximum clock error between the wireless master device C and the wireless slave devices M1 to Mn is ± 5 seconds, if T3 is set to 10 seconds or more, all the wireless slave devices are in the receiving state at time Tb. Reference numeral 11 denotes a carrier sense operation. That is, the wireless slave devices M1 to Mn repeatedly perform the carrier sense operation at the time interval T1 after starting the reception operation. C_TX indicates the transmission operation of the wireless master device C. When wireless base station C reaches time Tb, SND-UD1 shown in FIG. 5 is transmitted. Reference numeral 15 denotes SND-UD1. The signal length of SND-UD1 is T4. If the firmware rewrite data is divided into 500 kbytes and 200 bytes, the 500 kbyte data is divided into 2500 blocks. When 1 block = 200 bytes = 1600 bits is placed on one SND-UD, if the SND-UD length including the control information is 2048 bits, the transmission speed is 2400 bps, so T4 is about 853 milliseconds. Then, after the transmission suspension time T5 has elapsed, the wireless master device C transmits the SND-UD2 carrying the next block information. Reference numeral 16 denotes SND-UD2. Similarly, SND-UDn is sequentially transmitted across the pause time T5. The pause time T5 is 100 milliseconds or longer. Here, if T1 is set to 400 milliseconds, the wireless slave devices M1 to Mn can perform carrier sense twice during the time T4 during which the signal 15 that is SND-UD1 is transmitted. In the carrier sense operation at 12 timings indicated by white circles in FIG. 6, the carrier of the signal 15 can be detected. When the wireless slave devices M1 to Mn detect the carrier at the carrier sense timing 12, the carrier sense interval is changed from T1 to T2 so that the carrier sense operation is performed at a time interval T2 shorter than the transmission pause time T5. If the transmission pause time T5 is 100 milliseconds, T2 is set to 20 milliseconds, for example. A carrier sense timing 13 indicated by a black circle is a carrier sense operation at a timing T5, and indicates a timing at which no carrier is detected. In the case of FIG. 6, when it is determined that the carrier is not detected twice in succession, the wireless slave units M1 to Mn receive the signal 16 that is SND-UD2 to be transmitted next, assuming that the transmission pause time T5 is detected. Therefore, the process proceeds to the continuous reception operation 14.

  The operation described above will be further described with reference to FIG. At time Ta, the wireless slave devices M1 to Mn start the intermittent control means 3 by a signal from the control means 8, and the intermittent control means 3 intermittently turns on the power of the selective amplification means 2 and the carrier sense means 4 at a cycle T1. Then, the carrier sense operation is performed. The carrier sense operation is an operation for detecting whether or not the received signal level is equal to or higher than a predetermined signal level. The time to turn on the power for carrier sense is 10 ms or less. The first determination means 6 determines whether or not the signal 15 is detected. The determination method may be when the carrier is detected a predetermined number of times continuously in the T1 cycle, or when the carrier is detected twice during (3 × T1) time, for example. In the example of FIG. 6, it is determined that the signal 15 is detected if the carrier is detected even once. If the first determination means 6 determines that the signal 15 has been detected, the control means 8 instructs the intermittent control means 3 to change the intermittent period from T1 to T2. Then, the second determination means 7 determines whether or not there is a transmission pause time. The determination method for the presence or absence of the transmission pause time may be when the carrier cannot be detected a predetermined number of times continuously in the T2 cycle, or when the carrier cannot be detected twice during (3 × T2) time, for example. . When the second determination means 7 determines that there is no carrier, that is, there is a transmission pause time, the control means 8 instructs the intermittent control means 3 to always turn on the power of the selective amplification means 2 and activate the signal receiving means 5 to activate the signal. The regular notification device is shifted to a state where 16 can be received. Each of the first determination means 6 and the second determination means 7 has a time-out function. When the time-out period elapses after the respective determination means are activated, the control means 8 is notified, and the control means 8 performs the carrier sense operation. Is stopped, all power sources of the periodic notification device are turned off, and the system returns to the standby state. Also, after the transmission pause time is detected by the second determination means 7, the control means 8 also turns on all the power sources of the periodic notification device even if the signal reception means 5 cannot receive the frame packet shown in FIG. Turns off and returns to standby state.

  Through the operation described above, the wireless slave devices M1 to Mn can receive the SND-UDn message after the signal 16 and decode the firmware rewrite data. The wireless slave devices M1 to Mn cannot receive and decode the signal 15 which is the SND-UD1 signal. Therefore, it is only necessary to carry insignificant dummy data on the signal 15 and sequentially send a signal obtained by dividing the firmware rewrite data from the signal 16 every 200 bytes. Alternatively, the signal 15 and the signal 16 may send the same data. Alternatively, the firmware rewrite data included in the signal 15 may be transmitted again from the wireless master device after the SND-NR transmitted in the wireless slave devices M1 to Mn in the zones A, B, and C.

  In this embodiment, the information of the reception timing B at which each wireless slave device starts reception is transmitted by SND-UD from the wireless master device C shown in FIG. 4, and the wireless slave device that has received the reception timing B is in the zone D. The wireless slave device that has started reception at reception timing B and has not transmitted the SND-UD from the wireless master device C is configured not to receive in the zone D. It is not necessary to put on. When the information of the reception timing B is not put on the SND-UD, the information of the reception timing B is written in advance in each wireless slave device when the wireless slave device is installed, for example.

In addition, each wireless slave device may be configured to perform a reception operation at reception timing B in the zone D stored in advance, regardless of whether or not the SND-UD is received.

  As described above, the wireless master device can simultaneously broadcast large-capacity data such as firmware to each wireless slave device without greatly reducing the power consumption of each wireless device. .

DESCRIPTION OF SYMBOLS 1 Antenna 2 Selective amplification means 3 Intermittent control means 4 Carrier sense means 5 Signal receiving means 6 First determination means 7 Second determination means 8 Control means 9 Transmission means

Claims (4)

A wireless device that performs wireless communication with a transmitting device that transmits a second signal after a predetermined time has elapsed after transmitting the first signal,
A carrier sense unit that intermittently performs carrier sense realized by capturing a reception level of a signal transmitted from the transmission device, and detects the presence or absence of a signal according to the reception level of the signal;
If the presence of a signal cannot be detected in carrier sensing performed a predetermined number of times after the carrier sense unit detects the presence of the first signal, a receiving unit that starts a receiving operation for receiving the second signal;
An intermittent control unit for controlling the intermittent interval of carrier sense by the carrier sense unit ;
With
When the carrier sense unit detects the presence of the first signal, the intermittent control unit is T1 according to a period T5 from when the first signal is transmitted until the second signal is transmitted. A wireless device that changes the intermittent interval of carrier sense to T2. The carrier sense unit stops the carrier sense operation and shifts to a standby state when the first signal cannot be detected within a predetermined time.
The wireless device according to claim 1 . The carrier sense unit determines that the first signal has been detected continuously or when the first signal is detected a predetermined number of times within a predetermined time.
The wireless device according to claim 1 . The carrier sense unit stops the carrier sense operation and shifts to a standby state when the second signal cannot be detected within a predetermined time.
The wireless device according to claim 1 .

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