JP7510594B2 - Wireless communication system - Google Patents

Description

The present invention relates to a method for synchronizing radio devices in a radio transmission/reception system including a plurality of radio devices and a method for reducing power consumption of each radio device.

Conventionally, in order to achieve low power consumption in a wireless transmission/reception system consisting of multiple wireless devices, it has been necessary to operate each wireless device in a low power consumption mode not only during wireless transmission but also during wireless reception, except when necessary for wireless communication operation. This makes it necessary to synchronize wireless transmission and reception on the transmitting and receiving sides.

For example, Patent Document 1 proposes a method in which a wireless master transmits synchronization data for synchronous communication to multiple wireless slaves to establish synchronization, and then transmits and receives the necessary data between the master and each slave.

JP 2011-61690 A JP 2018-38023 A

However, in the method of Patent Document 1, even after synchronization is established between the parent unit and each child unit, when required data is sent or received, both the parent unit and each child unit must perform both transmission and reception operations, so there is a certain limit to how much power consumption can be reduced in both units.

The present invention has been made to solve the above-mentioned problems, and realizes low power consumption when each radio unit transmits and receives in a transmission/reception system consisting of multiple radio units, without any distinction between a master unit and a slave unit.

In the present invention, in a system consisting of a plurality of radio devices, a specific radio device, which is determined by a certain method, transmits a synchronization request signal and control data or collection data to the other radio devices at a first constant time interval, and the other radio devices receive the synchronization request signal from the specific radio device at a second constant time interval, which is an interval that is an integer multiple of the first constant time interval, thereby periodically establishing synchronization with the specific radio device and receiving the control data or collection data.

The specific radio determined by the above-mentioned method is, for example, the radio that is the first among multiple radios to be powered on and start operating. When the radio is powered on and starts operating, it first receives a synchronization request signal from the other radios, and in order to wait for a certain period of time for reception, the CPU of the radio operates in an operating mode (called a normal mode, operating mode = normal mode) rather than in a sleep mode (called a low power consumption mode, sleep mode = low power consumption mode).

If, after waiting for a certain period of time, a synchronization request signal cannot be received from another radio, the radio determines that its own radio was the first radio in the system to be powered on and start operating, and begins transmitting a synchronization request signal and control data or collection data to the other radio.

The radio device that receives the synchronization request signal from the specific radio device establishes synchronization with the specific radio device. The radio device that has established synchronization with the specific radio device further transmits the synchronization request signal and the control data or collection data to the specific radio device and the radio device other than itself in order to establish synchronization with the other radio device.

In detail, each wireless device that has established synchronization transmits the control data or collection data together with a synchronization request signal to the other wireless devices at the first fixed time intervals after the synchronization is established. This allows the control data or collection data to be shared among the wireless devices, and all of the wireless devices are synchronized.

Even if each wireless device loses synchronization with the other wireless devices once, the wireless device re-establishes synchronization with the other wireless devices by receiving a synchronization request signal from the other wireless devices at the first fixed time interval.

In each synchronized radio device, from the end of transmission of the synchronization request signal to the start of transmission of the next synchronization request signal after the first fixed time has elapsed, the device operates in a low power consumption mode, and performs intermittent transmission and reception in which no receiving operation is performed except when the synchronization request signal is received, thereby realizing low power consumption.

Furthermore, control data or collected data is transmitted and received between each of the wireless devices without the need to identify each of the wireless devices during wireless transmission and reception.

In the present invention, after the above-mentioned synchronization is established, a synchronization request signal and the control data or collected data are transmitted to another wireless device at the first fixed time interval, for example, every 2.1 seconds, and during this transmission, the CPU of the wireless device operates in normal mode (= operating mode). The operating mode in the normal mode at this time is called the transmission mode.

The synchronization request signal is received at intervals of a second fixed time, which is an integer multiple of the first fixed time, for example, every 2.1 seconds x 5 = 10.5 seconds, and the CPU of the radio device operates in normal mode (= operating mode) even when receiving the signal. The normal operating mode at this time is called the transmit/receive mode.

In this transmission/reception mode, when a synchronization request signal and control data or collected data are received from another radio, the radio transmits to other radio devices other than itself updated control data or collected data, or data identical to the received control data or collected data without updating, in response to the same synchronization request signal as the received synchronization request signal and its own sensor input, SW input, etc. (in response to transmitting sensor input acquired by its own radio to the outside as collected data, or transmitting it as control data for controlling the outside using the SW input of its own radio).

When transmitting updated control data or collected data, the timing of data transmission is made earlier than when not updated so that other wireless devices other than the wireless device itself can receive the updated control data or collected data in preference to non-updated control data or collected data similarly transmitted from the other wireless devices.

Taking this advance time into consideration, the operation time in the transmission/reception mode is determined. For example, if the timing for updating the control data or collected data is advanced by 20 ms, the operation time in the transmission/reception mode is set to, for example, 100 ms so that reception can be ensured.

In normal mode, except for the transmit mode and transmit/receive mode, the radio's CPU operates in low power consumption mode (=sleep mode). The power consumption reduction effect of each radio is as follows:
The smaller the normal mode operation time/(normal mode operation time+low power consumption mode operation time) is, the larger the power consumption becomes.

Since the operation time of the transmission/reception mode is relatively long compared to the operation time of the transmission mode, the operation time of the transmission/reception mode can be shortened in order to reduce power consumption.

To achieve this, the second fixed time, which is an interval that is an integer multiple of the first fixed time, can be lengthened; in other words, the integer multiple of the "integer multiple interval" can be increased. However, this will result in a longer time until a response is output in response to an input to the sensor input, SW input, etc., of the device itself, and will reduce responsiveness.

There is a trade-off between low power consumption and responsiveness, but it is sufficient to select the optimal value for the wireless transmission/reception system. In the wireless transmission/reception system of the present invention, synchronization is established between all the wireless devices that make up the system, so an orderly intermittent transmission/reception system is configured, and the system is capable of achieving the lowest possible power consumption not only during transmission but also during reception.

Here, the aforementioned low power consumption mode (=sleep mode) refers to a mode in which the CPU and radio circuitry stop program operation, such as so-called sleep operation, and only performs the minimum necessary operations at a low speed clock, making wireless transmission and reception operations impossible, but in exchange for minimizing power consumption, while the normal mode (=operating mode) refers to a mode in which the CPU and radio circuitry operate at a high speed clock, making wireless transmission and reception operations possible, but in exchange for increased power consumption.

In addition, by transmitting and receiving synchronization request signals between each radio device, it becomes possible for other radio devices to relay the radio signals containing control data or collection data even between radio devices that are too far away for the radio signals to reach directly, and by relaying, the control data or collection data is shared between all radio devices.

As mentioned above, the transmission and reception operations are the same between each radio device, and there is no need to distinguish between higher and lower ranks between each radio device. However, it is also possible to consciously perform the identification, connect to other devices within each radio device, and set functions to distinguish between special radio devices that give instructions and manage control data or collected data and other radio devices.

As described above, each radio device performs both transmission and reception, and reception is the above-mentioned operation, which is performed at second fixed time intervals that are an integral multiple of the first fixed time interval. Transmission is performed by transmitting a synchronization request signal to each radio device other than itself to establish synchronization with other radio devices, and by constantly transmitting the signal whether each radio device is receiving or not, even if the synchronization between its own radio device and other radio devices is lost, the other radio devices can restore and establish synchronization again by receiving the synchronization request signal that is constantly being transmitted.

The reception operation of each radio device in response to the synchronization request signal is as follows: Each radio device wakes up from the low power consumption mode to the normal mode earlier only at the preset timing for receiving the synchronization request signal, unlike when only normal data transmission operations are performed, and can therefore receive the synchronization request signal, but when only normal data transmission operations are performed, the radio device wakes up from the low power consumption mode to the normal mode after another radio device has transmitted the synchronization request signal, and therefore cannot receive the synchronization request signal.

Each radio device waits for a fixed time period for the synchronization request signal from the other radio devices at a preset timing for receiving the synchronization request signal, and if the synchronization request signal cannot be received during that time period, the radio device attempts to receive the synchronization request signal again at the next reception timing after an interval that is an integer multiple of the first fixed time period has elapsed.

According to the present invention, in a wireless transmission/reception system consisting of multiple wireless devices, each wireless device periodically transmits a synchronization request signal, and each wireless device receives the synchronization request signal, so that the timing of the start of the reception operation is adjusted to match the timing of the transmission. This allows the timing of transmission and reception to match between the wireless devices, and synchronized transmission and reception is realized between the wireless devices. Synchronization between the wireless devices enables intermittent transmission and reception between the wireless devices, and performing this intermittent transmission and reception realizes low power consumption for the system.

In this case, all the wireless devices are of the same rank, and there is no need to distinguish between higher and lower ranks. There is also no limit to the number of wireless devices. Furthermore, the frequencies and addresses used for transmission and reception between the wireless devices can be the same.

Even when direct transmission and reception is not possible between wireless devices due to distance issues, relay wireless devices are placed between them, and transmission and reception are repeated between adjacent wireless devices until finally, control data or collected data is shared between all wireless devices belonging to the system. By using multiple wireless devices and repeating relays, it is easy to significantly extend the wireless transmission distance.

It is assumed that the frequencies and addresses used for transmission and reception between each radio device are the same, but if interference is anticipated, the frequencies and addresses may be matched only when transmitting and receiving between adjacent radio devices, and either the frequency or the address, or both, may be changed at other times.

If the synchronization request signal is not periodically transmitted and received, the timing at which the radio devices start receiving control data or collected data will gradually deviate from the initial value due to differences in the operation reference clocks between the radio devices. Therefore, the value of this deviation will increase with each repetition of transmission and reception between the radio devices, but it can be returned to the initial value by periodically transmitting and receiving a synchronization request signal between the radio devices.

In addition, since each radio always transmits the synchronization request signal to the other radios whether the other radios receive the signal or not, even if a certain radio temporarily loses synchronization with the other radios, the radio can automatically restore synchronization by receiving the synchronization request signal from the other radios.

FIG. 1 is a timing chart showing transmission and reception of signals between radio devices in a radio transmission/reception system made up of a plurality of radio devices (four radio devices in this embodiment) according to the present invention. FIG. 2 is a block diagram of a low power consumption wireless communication system in which each wireless device of the present invention is a part of a slave device, and a slave device, a master device, and an external recording device for recording data are separately arranged.

Referring to FIG. 1, the transmission and reception timing of each signal in a wireless transmission and reception system comprising four wireless devices according to the present invention will be shown, and the procedure by which each wireless device operates with low power consumption will be described below.

(1) Each wireless device transmits a synchronization request signal WP to the other wireless devices every first fixed time TM, for example, every 2100 ms. Also, each wireless device receives a synchronization request signal from the other wireless devices every second fixed time = 2100 ms x 5 = 10500 ms, which is an interval that is an integer multiple (= 5 times) of the first fixed time (= 2100 ms). When receiving this synchronization request signal, the wireless device also receives control data or collection data from the other wireless devices.

(2) Here, it is assumed that wireless devices 1 to 4 are arranged in a straight line, and that due to the wireless transmission distance, transmission and reception are possible only between adjacent wireless devices, but transmission and reception may be possible between all four wireless devices 1 to 4. This is because, when each wireless device receives a synchronization request signal transmitted from another wireless device, the synchronization request signal received earlier is valid, and synchronization request signals transmitted later are not received and are ignored.

During the periods "1" to "4" and "6" to "8", the wireless device 1 is in low power consumption mode (=sleep mode) at the timing when a synchronization request signal WP is transmitted from another wireless device, and therefore cannot receive the synchronization request signal WP. During the periods "1" to "4" and "6" to "8", the wireless device 1 wakes up from the low power consumption mode to the normal mode (=operating mode) and performs a transmission operation (processing), then re-enters the low power consumption mode and waits for the first fixed time TM to elapse.

As mentioned above, the operation in normal mode at this time is called the transmission mode. In Fig. 1, A is the time during the fixed time interval TM during which the device is in the low power consumption mode, and α = TM - A is the time during the fixed time interval TM during which the device is in normal mode. This normal mode time α = TM - A is the transmission operation (processing) time of the wireless device in the transmission mode, and α = 1 ms, for example. The transmission operation (processing) is instantaneous, and typically the processing is completed in about 1 ms.

(3) In the period "5", the device wakes up from the low power consumption mode to the normal mode (= operating mode) and performs the transmission operation (processing) in the transmission mode, then enters the low power consumption mode for the period B, after which it returns to the normal mode again and performs the operation for receiving a synchronization request signal WP from another wireless device. The operation in the normal mode at this time is called the transmission/reception mode as described above, but since this transmission/reception mode requires time to wait for the synchronization request signal WP from another wireless device, the operation time B in the low power consumption mode is set shorter than the operation time A in the transmission mode.

For example, when TM=2100 ms, A is set to 2099 ms and B is set to 1999 ms. The value of B is determined taking into consideration the difference in the operation reference clock between each radio device and the set time difference between the transmission timing of control data or collected data when the control data or collected data is updated in response to sensor input, SW input, etc. and the transmission timing when the control data or collected data is not updated.

(4) During the period "2", wireless device 2 updates the control data or collected data from SIG1 to SIG2 in response to its own sensor input, SW input, etc., and transmits the updated data together with a synchronization request signal WP to the other wireless devices. However, the other wireless devices also transmit non-updated data SIG1 together with the synchronization request signal WP.

In order to have the other wireless devices receive SIG2 instead of SIG1, the wireless device 2 advances the transmission timing of the synchronization request signal WP and SIG2 compared to the other wireless devices. In the example shown in FIG.

1, the interval when the radio operates only in the transmit mode is denoted as TM, and the interval when the radio operates in the transmit/receive mode is denoted as RCV. In order to receive the synchronization request signal WP transmitted β=20 ms earlier and the updated control data or collection data, each radio wakes up from the low power consumption mode to the normal mode, for example, RCV-α-B=100 ms earlier during the second fixed time period of 10500 ms, which is an interval that is an integer multiple (=5) of the first fixed time period TM (=2100 ms).

This RCV-α-B corresponds to the reception waiting and reception operation (processing) time in the transmit/receive mode of each radio device, and in FIG. 1, as an example, it shows that radio device 1 wakes up from the low power consumption mode to the normal mode and waits to receive during the period "5", radio device 2 during the period "4", radio device 3 during the periods "3" and "8", and radio device 4 during the periods "1" and "6" by RCV-α-B = 100 ms earlier.

During this waiting period, if a synchronization request signal WP and control data or collection data are received from another radio device, the radio device is controlled so as not to receive any subsequent synchronization request signal WP and control data or collection data from the other radio device.

1, the updated SIG2 from wireless device 2 is notified to wireless device 3 during the period "3", wireless device 3 performs reception processing, and the control data or collection data transmitted from wireless device 3 is also updated to SIG2. The updated SIG2 from wireless device 2 is notified to wireless device 1 during the period "5", wireless device 1 performs reception processing, and the control data or collection data transmitted from wireless device 1 is also updated to SIG2.

The updated SIG2 from wireless device 3 is notified to wireless device 4 during the period "6", and the control data or collection data transmitted from wireless device 4 after wireless device 4 performs reception processing is also updated to SIG2.

In this way, the control data or collection data updated by wireless device 2 is transmitted to the other wireless devices 1, 3, and 4, where it is received and processed by each wireless device, and shared by all the wireless devices.

1 shows an example of the operation of transmitting and receiving SIG1 and SIG2, which will be described below. <1> indicates that each wireless device was transmitting SIG1 data, but wireless device 2 updated the data it holds from SIG1 to SIG2 due to a sensor input connected to that wireless device, etc., and therefore transmitted that data together with the WP.

<2> indicates that wireless device 2 received SIG1 data from wireless device 1, but because it recognized SIG2 as being more recent than SIG1 based on the timestamp etc. contained in the data, it sent SIG2 data, instead of SIG1, to wireless device 1 together with the WP.

<3> indicates that wireless device 1 received SIG2 data from wireless device 2, but because it recognized SIG2 as being more recent than SIG1 based on the timestamp etc. contained in the data, it transmitted the SIG2 data together with the WP to wireless device 2.

<4> indicates that wireless device 3 received SIG2 data from wireless device 2, but because it recognized SIG2 as being the newest data compared to SIG1 based on the timestamp etc. contained in the data, it transmitted the SIG2 data together with the WP to wireless device 2.

<5> indicates that wireless device 4 received SIG2 data from wireless device 3, but because the timestamp etc. contained in the data indicates that SIG2 is more recent than SIG1, it transmitted the SIG2 data together with the WP to wireless device 3.

The above-mentioned operation example also illustrates the case where SIG1 before the update is transmitted while SIG2 data is held, and shows that the timestamps in the SIG1 and SIG2 data are compared to indicate that SIG1 is the data before the update and SIG2 is the data after the update.

2 is a block diagram of a wireless communication system consisting of a wireless master unit and multiple wireless slave units. In this system, the part consisting of wireless slave unit 2 20, wireless slave unit 4 50, and wireless slave unit 5 60 is a low power consumption wireless transmission/reception system consisting of multiple wireless units based on the present invention.

Moreover, the wireless master 40, wireless slave 1 10, wireless slave 2 20, and wireless slave 3 30 constitute the wireless transmission/reception system described in Patent Document 2, and the system in Fig. 2 realizes low power consumption by intermittent transmission and reception as the whole system. However, in the system in Fig. 2, wireless slave 3 30 is connected to an external data recording device 70 via UART (UART TXD 71 and UART RXD 72) in order to record and store the control data or collected data acquired as the whole system.

The wireless slave device 3 30 does not need to be low power consuming because it receives power from an external data recording device 70. Here, the data recording device 70 is, for example, a combination of a UART-USB conversion circuit and a PC (personal computer), and has a function of converting UART format data output from the wireless slave device 3 30 into USB format data by the UART-USB conversion circuit, inputting the data into the PC, and recording and saving the data in the PC's recording device.

Communications between the wireless master device 40 and wireless slave device 1 10, wireless slave device 2 20, and wireless slave device 3 30, as well as communications between wireless slave device 2 20, wireless slave device 4 50, and wireless slave device 5 60, are performed in the 2.4 GHz frequency band. The wireless master device and each wireless slave device are all powered by button batteries, except for wireless slave device 3, which performs UART input/output and outputs data to an external recording device. Wireless slave device 3 receives power from the external recording device.

As described above, communication between each wireless device (between the wireless master device and the wireless slave device, and between the wireless slave devices) is performed in the 2.4 GHz frequency band, but other frequency bands other than 2.4 GHz may be used. Also, in the system of Fig. 2, it is assumed that the frequency and address for communication between each wireless device are the same (for example, the frequency is 2450 MHz), but it is possible to change them from the viewpoint of reducing the possibility of interference and from the viewpoint of reducing the processing load of the CPU part in each wireless device.

This reduction in the processing burden on the CPU in each radio means that if the frequency and address are the same, the CPU in each radio needs to analyze all of the messages involved in the communications between radios in the system, but if the frequency is changed, for example, the radio unit in each radio selects the messages, thereby reducing the burden on the CPU.

For example, it is possible to change the frequency and address as follows: transmission and reception between the wireless master device 40 and wireless slave device 1 10 is at a frequency of 2440 MHz and an address of "100", transmission and reception between the wireless master device 40 and wireless slave device 2 20 is at a frequency of 2450 MHz and an address of "200", transmission and reception between the wireless master device 40 and wireless slave device 3 30 is at a frequency of 2460 MHz and an address of "300", and communication between wireless slave device 2 20, wireless slave device 4 50, and wireless slave device 5 60 is at a frequency of 2450 MHz and an address of "200".

It is possible to change both the frequency and the address, or just one of them. If there is a system similar to the present invention nearby and there is a possibility of interference, it is possible to deal with the problem by changing the frequency or the address, as described above.

The wireless slave device 1 10 is supplied with a power of about 3 V from a button battery 11, and this power operates the CPU 14 and the wireless transmitting/receiving circuit 16. The CPU 14 has two oscillators, a high-speed clock oscillator 12 (16 MHz) and a low-speed clock oscillator 13 (32.768 kHz), and operates with two reference clocks.

The high-speed clock oscillator 12 generates a 16 MHz high-speed clock as an operating clock for the program of the CPU 14 and as a reference clock for the 2.4 GHz radio signal. The 2.4 GHz radio signal is generated by multiplying the 16 MHz high-speed clock by a PLL.

The low-speed clock oscillator 13 generates a low-speed clock of 32.768 kHz, which serves as various reference timers when the CPU 14 is operating in normal mode, and which continues counting up even in the low-power consumption mode, and is used as a timer for returning from the low-power consumption mode to the normal mode.

In the normal mode of the slave unit 1 10, both the high-speed clock 16 MHz and the low-speed clock 32.768 kHz of the CPU 14 operate.
In the low power consumption mode, the high-speed 16 MHz clock of the CPU 14 is stopped, and therefore the operation of the program of the CPU 14 is also stopped, and the CPU 14 enters a so-called sleep state.

Even in the low power consumption mode, the timer count operation continues based on the low-speed clock of 32.768 kHz, and after entering the sleep mode, after a certain period of time based on this low-speed clock of 32.768 kHz has elapsed, the CPU 14 wakes up from the sleep mode, transitions to the normal mode, and resumes program operation.

In the embodiment of the present invention, the operations between the wireless master device 40 and the wireless slave device 1 10, the wireless slave device 2 20, and the wireless slave device 3 30 will be described with reference to the wireless transmission/reception system in Patent Document 2. After transmitting a wireless data signal to the wireless master device 40, the CPU 14 of the wireless slave device 1 10 immediately enters a sleep state, and after entering the sleep state, the cycle of waking up from the sleep state is 2.1 seconds.

The wireless master device 40 repeatedly transmits synchronization request signals WP1, WP2, WP3, WP1, -, -, - to wireless slave device 1 10, wireless slave device 2 20 and wireless slave device 3 30 every 0.7 seconds, and wireless slave device 1 10, wireless slave device 2 20 and wireless slave device 3 30 repeatedly transmit ACK signals ACK1, ACK2, ACK3, ACK1, -, -, - which correspond to the aforementioned wireless data signals, to the master device in response to the synchronization request signals.

The SW 15 of the wireless slave device 1 10 is a switch for controlling the wireless master device 40, and the ON/OFF state of the switch is input to the CPU 14. The operation of the wireless slave device 2 20 is the same as that of the wireless slave device 1 10. The operation of the wireless slave device 3 30 is basically the same as that of the wireless slave device 1 10, except that the wireless slave device 3 30 performs an operation for recording data. Details will be described later.

The wireless master device 40 transmits synchronization request signals WP1 101, WP2 103, and WP3 to wireless slave device 1 10, wireless slave device 2 20, and wireless slave device 3 30, in that order, and wireless slave device 1 transmits an ACK1+Data1 signal 102 in response, which is an ACK signal plus a control signal based on SW15 (not limited to a control signal based on SW15, but may be control data based on other inputs or collected data based on inputs from a sensor, etc.).

Similarly, in response, wireless slave device 2 transmits a control signal ACK2+Data2 signal 104 based on SW25. As a result, the wireless master device 40 holds the data of the control signal based on SW15 of wireless slave device 1 and the control signal based on SW25 of wireless slave device 2 transmitted from wireless slave device 1 10 and wireless slave device 2 20, respectively.

In order to record these data externally, the wireless master device 40 transmits a synchronization request signal WP3+Data1+Data2 105 instead of the synchronization request signal WP3 to the wireless slave device 3 30. After receiving the synchronization request signal WP3+Data1+Data2 105, the wireless slave device 3 30 transmits an ACK3 signal 106 as a response.

Upon receiving the synchronization request signal WP3+Data1+Data2 105, wireless slave device 3 30 possesses data based on the control signals from wireless slave device 1 10 and wireless slave device 2 20, and operates to record and store this data in the external recording device 70 via its own UART terminal (by wired transmission and reception at UART TXD 71 and UART RXD 72).

Wireless slave device 4 50 and wireless slave device 5 60, in combination with wireless slave device 2 20, constitute a low power consumption wireless transmission/reception system consisting of multiple wireless devices of the present invention. When wireless slave device 2 20 receives a synchronization request signal WP2 from wireless master device 40, it returns an ACK2+Data2 signal 104 to wireless master device 40, but at the same time, it also transmits the same ACK2+Data2 signal 104 to wireless slave device 4 50, and wireless slave device 4 receives the ACK2+Data2 signal 104.

Due to the wireless transmission distance, there is a possibility that wireless slave unit 5 60 also receives the ACK2+Data2 signal 104 at the same time. However, in the low power consumption wireless transmission/reception system of the present invention consisting of multiple wireless units, even when the same data is received from multiple wireless units, the system enters a receiving state and only the data received first becomes valid. After receiving the data, the system exits the receiving state, and subsequent data is ignored, so there is no problem.

After receiving the ACK2+Data2 signal 104, the wireless slave device 4 50 identifies the control state based on its own SW 55, and transmits an ACK2+Data2 signal 107 to the wireless slave device 5 60, taking into consideration whether or not to update the Data2 portion of the signal 104. The ACK2+Data2 signal 107 is also transmitted to the wireless slave device 2 20.

After receiving the ACK2+Data2 signal 104, the wireless slave device 5 60 identifies the control state based on its own SW 65, and transmits an ACK2+Data2 signal 108 to the wireless slave device 4 50, taking into consideration whether or not to update the Data2 portion of the signal 107.

Here, wireless slave device 4 50 and wireless slave device 5 60 transmit and receive the ACK2+Data2 signal (ACK2+Data2 signals 104, 107, 108), while wireless slave device 2 20 transmits and receives the ACK2+Data2 signal (ACK2+Data2 signals 104, 107) and also receives the synchronization request signal WP2.

The total control state, which is a combination of the control states of the SW25, SW55 and SW65 of the wireless slave device 2 20, the wireless slave device 4 50 and the wireless slave device 5 60, is shared by the transmission and reception of the ACK2+Data2 signal.

The time until this sharing occurs is the first fixed time = 2.1 seconds because wireless slave device 2 20 returns an ACK signal every 2.1 seconds. If this is multiplied by an integer, for example 5, then the second fixed time = 2.1 seconds x 5, or 10.5 seconds.

When the wireless slave device 2 20 receives the synchronization request signal WP2 from the wireless master device 40, it returns the ACK2+Data2 signal shared among the wireless slave device 2 20, the wireless slave device 4 50, and the wireless slave device 5 60 at that time.

The wireless master unit 40 is supplied with power of about 3 V from a button battery 41, and this power operates the CPU 44 and the wireless transceiver circuit 46. The CPU 44 has a high-speed clock oscillator 42 (16 MHz) and a low-speed clock oscillator 43 (32.768 kHz), and operates on two reference clocks.

The high-speed clock oscillator 42 generates a 16 MHz clock as an operating clock for the CPU 44 program and as a reference clock for the 2.4 GHz radio signal. The 2.4 GHz radio signal is generated by multiplying the 16 MHz high-speed clock by a PLL. The low-speed clock oscillator 43 generates a 32.768 kHz low-speed clock, which is used as various reference timers when the CPU 44 is operating in normal mode and as a timer that continues counting up even in low power consumption mode and wakes up from low power consumption mode to normal mode.

In the normal mode of the wireless master device 40, both the high-speed clock 16 MHz and the low-speed clock 32.768 kHz of the CPU 44 are operating. In the low power consumption mode, the high-speed clock 16 MHz of the CPU 44 is stopped, and therefore the operation of the program of the CPU 44 is also stopped, and the CPU 44 enters a so-called sleep state. Even in the low power consumption mode, the timer count operation based on the low-speed clock 32.768 kHz continues, and after entering the sleep state, after a certain period of time based on the low-speed clock 32.768 kHz has elapsed, the CPU 44 wakes up from the sleep state, transitions to the normal mode, and resumes the operation of the program.

The wireless master device 40 displays its controlled state by displaying LED1 47 and LED2 48 as ON/OFF based on the control by the SW ON/OFF from the wireless slave device 1 10 and the wireless slave device 2 20. The ON/OFF display of LED1 47 and LED2 48 corresponds to the ON/OFF input of SW15 and SW25 of the wireless slave device 1 10 and the wireless slave device 2 20, respectively.

The ON/OFF display of LED3 49 corresponds to the total control state (e.g., the AND or OR of the states of each switch) that combines the control states of SW25, SW55 and SW65 of wireless slave unit 2 20, wireless slave unit 4 50 and wireless slave unit 5 60.

The present invention is used in a wireless transmission/reception system in which it is necessary to reduce power consumption during transmission and reception between a plurality of wireless devices and to extend the wireless transmission distance.

10 Wireless slave unit 1
11 Button battery 12 High-speed clock oscillator (16 MHz)
13 Low-speed clock oscillator (32.768 kHz)
14 CPU
15 SW
16 Wireless transmission/reception circuit 20 Wireless slave unit 2
25 SW
30 Wireless slave unit 3
40 Wireless base station 41 Button battery 42 High-speed clock oscillator (16 MHz)
43 Low-speed clock oscillator (32.768 kHz)
44 CPU
46 Wireless transmitter/receiver circuit 47 LED1
48 LED2
49 LED3
50 Wireless slave unit 4
55 SW
60 Wireless slave unit 5
65 SW
70 Data recording device 71 UART signal TXD
72 UART signal RXD
101 Synchronization request signal WP1 from the wireless master to the wireless slave 1
102 ACK signal ACK1+Data1 from wireless slave device 1 to wireless master device
103 Synchronization request signal WP2 from the wireless master device to the wireless slave device 2
104 ACK signal from wireless slave device 2 to wireless master device and wireless slave device 4
ACK2+Data2
105 Synchronization request signal from the wireless master to the wireless slave 3
WP3 + Data1 + Data2 (adds control data for each wireless slave unit 1 to 5)
106 ACK signal ACK3 from wireless slave device 3 to wireless master device
107 From wireless slave device 4 to wireless slave device 2 and wireless slave device 5
ACK signal ACK2+Data2
108 ACK signal ACK2+Data2 from wireless slave device 5 to wireless slave device 4
TM Interval when the radio is in transmit mode only RCV Interval when the radio is in transmit/receive mode A Time when the radio is in low power consumption mode
(When operating in transmit mode at each interval)
B. Low power consumption mode time of the radio
(When operating in transmit/receive mode at each interval)
WP: Synchronization request signal SIG1 from one radio to another radio. Control data or collected data SIG2: Updated in response to sensor inputs, SW inputs, etc. of one radio.
Control data or collected data to be transmitted α Transmission operation (processing) time in the radio's transmission mode β Radio interval immediately after updating the control data or collected data
(Low power consumption mode time) Time reduction <1> Operation example
Each wireless device was transmitting SIG1 data, but wireless device 2 updated the data it held from SIG1 to SIG2 due to a sensor input connected to that wireless device, etc., and transmitted that data together with the WP. <2> Operation example
Wireless device 2 receives SIG1 data from wireless device 1, but because it recognizes SIG2 as the latest data based on the timestamp included in the data, it sends SIG2 data, not SIG1, together with the WP to wireless device 1. <3> Operation example
Wireless device 1 receives data on SIG2 from wireless device 2, but because it recognizes SIG2 as the latest data based on the timestamp etc. included in the data, it transmits the data on SIG2 together with the WP to wireless device 2. <4> Operation example
Wireless device 3 receives data on SIG2 from wireless device 2, but because it recognizes SIG2 as the latest data compared to SIG1 based on the timestamp etc. included in the data, it transmits the data on SIG2 together with the WP to wireless device 2. <5> Operation example
Radio 4 receives the SIG2 data from radio 3, but because it recognizes that SIG2 is the latest data compared to SIG1 based on the timestamp etc. included in the data, it transmits the SIG2 data together with the WP to radio 3.

Claims (4)

a first fixed time interval, the other radio devices receiving the synchronization request signal from said one radio device at a second fixed time interval, the second fixed time interval being an interval that is an integer multiple of two or more of the first fixed time interval, thereby periodically establishing synchronization with said one radio device and receiving the control data or collection data; and each of said radio devices that has established synchronization further transmits the control data or collection data and a synchronization request signal to other radio devices other than itself at the first fixed time interval after establishing synchronization, thereby enabling all of the radio devices to share the control data or collection data, and all of the radio devices are synchronized, so that the timing at which a reception operation starts coincides with the transmission timing . 2. The wireless communication system according to claim 1, characterized in that by transmitting and receiving a synchronization request signal between each of the wireless devices, a deviation in the timing at which the receiving operation starts due to a difference in the operation reference clock between each of the wireless devices is cleared, and the timing at which the receiving operation starts is returned to an initial value. 3. The wireless communication system according to claim 1, wherein identification of each wireless device is not required during wireless transmission/reception. A wireless communication system as described in any one of claims 1 to 3, characterized in that by transmitting and receiving a synchronization request signal between each wireless device, it becomes possible for other wireless devices to relay the wireless signal containing the control data or collection data even between wireless devices that are too far away for the wireless signals to reach directly, and by relaying, the control data or collection data is shared between all wireless devices.

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