JP7510591B2 - Wireless communication synchronization system - Google Patents

Description

The present invention relates to a mechanism for achieving synchronization among multiple wireless devices and sharing data in a wireless transmission/reception system made up of multiple wireless devices.

Conventionally, in a wireless transmission/reception system consisting of multiple wireless devices, in order for data held by each wireless device to be shared among them, it is necessary to determine in advance which wireless device will transmit and receive data between them, and data acquired by one specific wireless device is transmitted to a physically adjacent wireless device, which then transmits the data to an adjacent wireless device, and so on, with each wireless device repeating the transmission and reception in turn to allow the data to be shared among the wireless devices.

For example, Patent Document 1 proposes a system in which a plurality of wireless devices relay information between adjacent wireless devices in a relay manner.

JP 2013-175868 A

However, in the method of Patent Document 1, in order to share data among the radio devices, a means was required to specify and identify each radio device, such as transmitting data from one specific radio device to another specific radio device.

The present invention has been made to solve the above-mentioned problems, and provides a mechanism in a transmission/reception system consisting of multiple radio devices, whereby each radio device can be synchronized without identifying each radio device, and because of this synchronization, each radio device can operate intermittently. As a result of the intermittent operation, each radio device can consume less power, and further, the radio devices can transmit and receive data to each other, thereby sharing control data or collected data.

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 operating mode, operating mode = normal operating 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 the collected data to the other radio device 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 simultaneously with a synchronization request signal to the other wireless devices at the first constant time intervals after the synchronization is established, whereby synchronization is achieved between the wireless devices and the control data or collection data is shared among all the wireless devices.

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, when wireless transmission and reception is performed between each of the wireless devices, control data or collected data is transmitted and received between each of the wireless devices without identifying the other wireless device with which the wireless device is transmitting and receiving.

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 250 ms, and during this transmission, the CPU of the wireless device operates in a normal operation mode (= operating mode). The operation mode in the normal operation mode at this time is called a 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 250 ms x 120 = 30 seconds, and the CPU of the radio device operates in a normal operation mode (= operating mode) even when receiving the signal. The normal operation mode at this time is called a transmission/reception 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 updated control data or collected data, or data identical to the received control data or collected data without updating, to other radios other than the radio itself in response to the 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 SW input of its own radio).

A timestamp or the like is added to the control data or collected data, and when updated control data or collected data is transmitted, the radio device that receives the data compares the values of the timestamp or the like and, if it decides to newly import the updated control data or collected data, it then transmits the updated control data or collected data to other radio devices.

By repeating this transmission and reception, the updated control data or collected data is shared among the wireless devices in a transmission and reception system made up of multiple wireless devices.

In a transmission/reception system consisting of multiple radio devices, when a synchronization request signal and control data or collection data are transmitted and received between one radio device and another, the mechanism by which the data is transmitted and received between each of the radio devices and how the transmission and reception partners are selected is not fixed, as will be described later.

In normal operation mode, except for the transmit mode and transmit/receive mode, the radio's CPU operates in low power consumption mode (=sleep mode). The effect of reducing the power consumption of each radio increases as the ratio (operation time in normal operation mode / (operation time in normal operation mode + operation time in low power consumption mode)) decreases.

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 would result in a longer time for other radio devices to recognize input values to sensor inputs, SW inputs, etc. in one's own radio device and output them as a response, reducing 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 with a low-speed clock, making wireless transmission and reception operations impossible, but in exchange for minimizing power consumption, while the normal operation mode (=operating mode) refers to a mode in which the CPU and radio circuitry operate with 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 described above, each wireless device performs both transmission and reception operations, of which reception is the above-mentioned operation, and is performed at second fixed time intervals which are an integer multiple of the first fixed time interval.

The transmission is a synchronization request signal for establishing synchronization with other radio devices, which is always transmitted whether each radio device receives the signal or not. Even if the synchronization between the radio device itself and other radio devices is lost, the other radio devices can restore and establish synchronization by receiving the synchronization request signal that is always 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 operation mode earlier only when it is at the preset timing to receive the synchronization request signal, unlike when it is timing to perform only the transmission operation of normal data (the above-mentioned synchronization request signal and control data or collection data; the same applies hereinafter until the definition is changed), so it can receive the synchronization request signal, but when it is timing to perform only the transmission operation of normal data, it wakes up from the low power consumption mode to the normal operation mode after another radio device has transmitted the synchronization request signal, so it 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.

In a transmission/reception system consisting of multiple radio devices, when data is transmitted and received between one radio device and another, in the present invention, which radio devices transmit and receive data between is determined each time using random numbers or the like, and the destination of data transmission and reception between the radio devices is not fixed.

This non-fixed mechanism avoids the problem of data collisions due to the fact that the data transmission and reception destination between wireless devices is undefined. In other words, since the transmission and reception destination is determined based on a random number, even if a data collision occurs at a certain timing, the transmission and reception destination will be different at the next timing, so there is a high possibility that the collision can be avoided.

Next, the operation of waking up from the low power consumption mode to the normal operation mode is synchronized between the wireless devices, and the time period during which transmission and reception are possible between the synchronized wireless devices is the same for each wireless device.

Therefore, initially all radio devices are synchronized and share data (the above-mentioned control data or collected data; this will be the same hereafter until the definition is changed), but if for some reason the multiple radio devices in the system are divided into two or more groups and the time periods in which they can transmit and receive differ between them, the synchronization request signal and data cannot be received between the two groups, and as a result, the two groups cannot be synchronized, and data that is shared between the two groups cannot be shared between the groups.

In the present invention, to address this issue, each radio device generates selection information whose value changes randomly for each radio device, and transmits this selection information together with the data transmitted simultaneously with the synchronization request signal. The other radio devices receive and decode the selection information and determine whether or not they should accept the transmitted data. Only when they determine that the data should be accepted do they establish synchronization and accept the data. If they determine that the data should not be accepted, they then receive the selection information from other radio devices. By controlling the transmission partner when one radio device receives to change randomly, a mechanism is established in which the transmission partner between each radio device is not fixed.

When a system is divided into two or more groups, the time periods during which transmission and reception are possible are different between the two groups, and therefore the groups are unable to transmit and receive synchronization request signals and data to each other. In a state in which a radio device in one group constantly receives synchronization request signals and data from a specific other radio device in the group and maintains synchronization and data sharing, if it determines that it should not receive data from that specific radio device, it may be able to receive a synchronization request signal from a radio device outside the group.

By receiving a synchronization request signal from a radio device outside this group, the state in which the groups were separated is released and all radio devices receive synchronization request signals in the same time zone, resulting in all radio devices in the system being synchronized and allowing all radio devices to return to a state in which they can share data.

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, thereby adjusting the timing of the start of the reception operation to match the transmission timing.

This allows the transmission and reception timing to match between each wireless device, and by matching the transmission and reception timing, intermittent transmission and reception operation becomes possible between each wireless device, thereby achieving low power consumption as a system.

In addition, all the radios are of the same rank, so there is no need to distinguish between higher and lower ranks, and there is no limit to the number of radios. Also, there is no problem with the frequencies and addresses used for transmission and reception between the radios being 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.

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.

In the present invention, when receiving a synchronization request signal and data between each wireless device in the system, there is no problem if the frequencies and addresses used for transmission and reception are the same for each wireless device in the system, i.e., there is no need to identify each wireless device.

At this time, when a radio device receives a synchronization request signal and data from another radio device, there is a possibility that the synchronization request signal and data will be received from multiple radio devices. In this case, processing will be performed using the synchronization request signal and data received earliest. However, since the difference in transmission time from the multiple radio devices is small, it is possible that the synchronization request signals and data transmitted from the multiple radio devices will collide.

To deal with this problem, in the present invention, a delay that is an integer multiple of the data transmission time is generated in data transmission and reception between each wireless device, and the integer value of the integer multiple is varied to create a mechanism in which the data transmission time is not fixed for each data transmission and reception timing, thereby avoiding the problem of data collision. In other words, even if a collision occurs between data transmitted from another wireless device at a certain timing and data transmitted from another wireless device, the aforementioned integer value will be different at the next timing, so that the transmission time from the other wireless device will differ from the transmission time, increasing the possibility that a collision can be avoided at the next timing.

Specifically, a delay is provided in the transmission time between each wireless device using random numbers, etc. The delay in transmission time = data transmission time x random number value.

If the transmission data = 40 bytes and the transmission speed = 250 kbps, then the transmission time = 40 x 8/250,000 = 1.28 ms, and if the transmission time delay = 1.5 ms x random number value (for example, a random value with possible values of 0, 1, and 2), then even if a data collision occurs at a certain time, there is a high possibility that a collision can be avoided at the next time.

In addition, in the present invention, a mechanism is created in which the data destination is not fixed by using random numbers or the like in data transmission and reception between each wireless device, so that unexpected grouping does not occur by chance in data transmission and reception between each wireless device, which causes problems in data transmission and reception.

In other words, if initially all radio devices are synchronized and all data are shared, but for some reason the multiple radio devices in the system are divided into two or more groups and the time periods in which transmission and reception are possible differ between the two groups, it is possible that they will not be able to transmit and receive synchronization request signals and data to each other, the two groups will not be able to synchronize, and data will not be able to be shared between the two groups.

If the system is split into groups for some reason, for example, initially four radio devices in the system were synchronized and data was shared among the four radio devices, but then the system splits into groups of two, sending and receiving synchronization request signals and data is completed within each group, so synchronization and data sharing between the groups will no longer be possible.

In this case, since the transmission and reception of the synchronization request signal and data is completed within each group, there is no problem if the time periods for transmitting and receiving the synchronization request signal and data are different, so the time periods for transmission and reception naturally move in different directions. (The operation of waking up from low power consumption mode to normal operation mode is synchronized between each synchronized radio device in a group, and the time periods during which transmission and reception can be performed are the same between each synchronized radio device.)

The general operation is for each radio device to transmit and receive a synchronization request signal and data to establish synchronization between the radio devices and share the data between them, but in order to eliminate grouping, random numbers or the like are used and selection information is included in the data that indicates that the data will not be accepted even if it is received depending on the random number value.

In other words, a radio device may at one time receive but not accept a synchronization request signal and data from a specific radio device, and at another time receive but not accept a synchronization request signal and data from another specific radio device; in other words, a radio device may randomly generate a synchronization request signal and data that it transmits that is not accepted by other radio devices, thereby providing a mechanism for not fixing the transmitting or receiving partner between each radio device.

This mechanism prevents a grouping condition from occurring, and also allows the condition to be resolved quickly if it does occur.

FIG. 1 is a diagram showing the transmission and reception timing of a synchronization request signal and data transmitted and received between each wireless device in a wireless communication synchronous system comprising a plurality of wireless devices (four wireless devices in this embodiment) according to the present invention.

However, a start counter is used as selection information whose value changes randomly for each radio. The start counter counts up at regular intervals after each radio starts operating, and transmits its value when transmitting a synchronization request signal and data. When receiving a synchronization request signal and data from another radio, the value is decoded and each radio determines whether or not to receive the transmitted data.

WP is a synchronization request signal, and SIG1 to SIG4 are data (control data or collected data) transmitted from each of the four wireless devices along with the synchronization request signal WP, and include a start counter s and data d shared by each wireless device.

FIG. 2 is a diagram showing the transmission and reception timing of a synchronization request signal and data transmitted and received between each wireless device similar to that shown in FIG.

However, as selection information whose value changes randomly for each wireless device, a timestamp is used that is input at the time of sensor input, etc. The timestamp transmits its value when transmitting a synchronization request signal and data, and when receiving a synchronization request signal and data from another wireless device, the value is decoded and each wireless device determines whether or not to receive the transmitted data.

WP is a synchronization request signal, and SIG1 to SIG4 are data (control data or collected data) transmitted from each of the four wireless devices together with the synchronization request signal WP, and include a time stamp t and data d shared by each wireless device.

FIG. 3 shows an example of transition of the start counter value of each wireless device and transition of the transmission/reception destination when six wireless devices are installed in the wireless communication synchronous system of the present invention.

FIG. 4 is a continuation of FIG. 3 and shows an example of the transition of the start counter value of each wireless device and the transition of the transmitting and receiving destinations.

FIG. 5 is a block diagram of a synchronous wireless communication system of the present invention, in which six wireless devices are installed, one of which is equipped with an external recording device for recording data.

FIG. 6 is a flowchart showing the operation of each wireless device in the wireless communication synchronous system of the present invention.

Based on Figures 1 and 2, the transmission and reception timing of each signal in a wireless transmission and reception system consisting of four wireless devices in the present invention is shown, and the procedure for achieving synchronization between the wireless devices and operating with low power consumption as a result of this synchronization is 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 250 ms. Also, each wireless device receives a synchronization request signal WP from the other wireless devices every second fixed time = 250 ms x 120 = 30 s, which is an interval that is an integer multiple (for example, 120 times) of the first fixed time (= 250 ms). When receiving this synchronization request signal WP, the wireless device also receives control data or collection data SIG from the other wireless devices.

For simplicity, in FIG. 1 and FIG. 2, the explanation is given assuming that the interval of an integer multiple of the first certain time is 5, and the second certain time is 250 ms×5=1250 ms.

(2)
Here, it is assumed that radio devices 1 to 4 are physically arranged in a straight line, and that due to the radio propagation distance, transmission and reception is possible only between adjacent radio devices; however, transmission and reception may be possible between all four radio devices 1 to 4.

This is because, when each wireless device receives synchronization request signals WP transmitted simultaneously from other wireless devices, the synchronization request signal WP received earlier becomes valid, and the synchronization request signal WP transmitted later is not received and becomes invalid, so that interference does not occur.

As described above, a mechanism is provided in which the transmission time delay (in the case of transmission time = 40 (bytes) x 8 (bit) / 250,000 (bps) = 1.28 ms, the transmission time delay = 1.5 ms x random value (for example, a random value with possible values of 0, 1, and 2) is set so that the transmission time of the synchronization request signal WP is not fixed, and therefore, when each wireless device receives the synchronization request signal WP, the wireless device that transmitted the synchronization request signal WP is random and not fixed.

During the periods "2" to "4" and "6" to "8", the wireless device 1 is in the low power consumption mode (=sleep mode) at the timing when the synchronization request signal WP is transmitted from the other wireless devices, and therefore cannot receive the synchronization request signal WP. During the periods "2" to "4" and "6" to "8", the wireless device 1 wakes up from the low power consumption mode to the normal operation 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 the normal operation mode at this time is called the transmission mode. In Fig. 1, A is the time during the low power consumption mode during the fixed time interval TM, and α = TM - A is the time during the fixed time interval TM during the normal operation mode.

The time α=TM-A during which the radio is in the normal operation mode is the transmission operation (processing) time during the transmission mode of the radio, and is, for example, α=1 ms. The transmission operation (processing) is instantaneous, and typically, the processing is completed in about 1 ms.

(3)
During period "5", the device wakes up from the low power consumption mode to the normal operation mode (= operating mode) and performs the transmission operation (processing) in the transmission mode, then enters the low power consumption mode for the period B, and then returns to the normal operation mode again to perform the operation for receiving the synchronization request signal WP from the other wireless device.

The operation in the normal operation mode at this time is called the transmit/receive mode as mentioned above. In this transmit/receive mode, since a waiting time is required for a synchronization request signal WP from another radio device, the operating time B in the low power consumption mode is set shorter than A in the transmit mode.

For example, when TM=250 ms, B is set to 200 ms. (As described above, A is about 249 ms obtained by subtracting from TM the transmission operation (processing) time of the wireless device in the transmission mode, which is about 1 ms.)

The value of B is set so as to provide a timing at which a synchronization request signal WP can be reliably received from other wireless devices, taking into consideration differences in the operation reference clocks between the wireless devices.

(4)
During the period "2", there is a change in the sensor input, SW input, etc. of wireless device 2, and therefore the control data or collected data corresponds to its own sensor input, SW input, etc., and the shared data d of each wireless device among the data transmitted as SIG2 is updated from d=0 to d=1.

Then, the updated data is transmitted to the other wireless devices together with a synchronization request signal WP, but the other wireless devices also transmit non-updated shared data d=0 together with the synchronization request signal WP.

In order for radio device 2 to have other radio devices receive SIG2 containing the updated d=1, rather than SIG1, SIG3, or SIG4 containing d=0 from other radio devices, in the system using the start counter of FIG. 1, the value of the start counter s contained in SIG2 is made larger than usual and transmitted together with the synchronization request signal WP.

That is, normally the received s is incremented by +1 and transmitted to other radio devices, but since there has been a change in the sensor input, SW input, etc., resulting in a change in the shared data in each radio device, in order to notify the other radio devices of this change preferentially, after receiving a SIG (which refers to any of the control data or received data of SIG1 to SIG4, the same applies below), the s contained in the received SIG is incremented by +2 instead of +1 and transmitted to the other radio devices.

In a system using the timestamp of Figure 2, in order to have SIG2 containing the updated d = 1 received, the value of the timestamp also contained in SIG2 is updated to a larger value and transmitted together with the synchronization request signal WP.

That is, normally, the received value of t is transmitted to other radio devices without any change, but since there has been a change in the sensor input, SW input, etc., and a change has occurred in the shared data of each radio device, in order to notify the other radio devices of this change preferentially, the value of t contained in the SIG received the previous time when the SIG was received is not left as it is, but is updated to the value of the current timestamp (the value of t contained in the previously received SIG is updated to a larger value) and transmitted to the other radio devices.

In FIG. 1 and FIG. 2, an interval when the radio operates only in the transmit mode is denoted as TM, and an interval when the radio operates in the transmit/receive mode is denoted as RCV.

In order to receive a synchronization request signal WP and control data or collection data SIG from other radio devices, each radio device wakes up from the low power consumption mode to the normal operation mode every second fixed time period of 1250 ms, which is an interval that is an integer multiple (=5) of the first fixed time period TM (=250 ms), for example, RCV-α-B = 50 ms earlier.

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 Figures 1 and 2, as an example, it is shown that radio device 1 wakes up from the low power consumption mode to the normal operation mode and waits to receive during the period "5", radio device 2 during the periods "3" and "8", radio device 3 during the periods "2" and "7", and radio device 4 during the periods "1" and "6" only by RCV-α-B = 50 ms earlier.

During this waiting period, when a synchronization request signal WP and control data or collection data SIG are received and accepted from another radio device (the shared data of each radio device is accepted), the radio device is controlled so that it does not receive any subsequent synchronization request signals WP and control data or collection data from the other radio devices.

In order to be accepted, when using the start counter in FIG. 1, the received start counter must be greater than or equal to the self-owned start counter, and when using the timestamp in FIG. 2, the received timestamp must be greater than or equal to the self-owned timestamp.

1 and 2, d included in the updated SIG from wireless device 2 is also updated to d = 1. d = 1 is notified to wireless device 3 during the period "2", wireless device 3 performs reception processing, and d included in the SIG transmitted from wireless device 3 is also updated to d = 1.

The d=1 included in the updated SIG from wireless device 2 is notified to wireless device 1 during the period "5", and wireless device 1 performs reception processing. As a result, d included in the SIG transmitted from wireless device 1 is also updated to d=1.

The d=1 included in the SIG updated by wireless device 3 is notified to wireless device 4 during the period of “6”, and wireless device 4 performs the receiving process and the d included in the SIG transmitted from wireless device 4 is also updated to d=1.

In this way, d=1 included in the SIG updated by wireless device 2 is transmitted to the other wireless devices 1, 3, and 4, and is received and processed by each wireless device, and is shared by all wireless devices.

1 and 2 show an example of the operation of transmitting and receiving d included in this SIG, which will be described below.

Up until now, each radio device had been transmitting data of d=0 included in SIG, but in <1>, radio device 2 updated the data of d it holds from d=0 to d=1 due to a sensor input connected to that radio device, etc., and therefore transmitted the data of d together with the WP immediately afterwards.

<2> indicates that wireless device 3 received data d=1 from wireless device 2, but based on the start counter value or timestamp transmitted and received along with the d data, it recognized that d=1 was the most recent data rather than d=0, and therefore transmitted data d=1, not d=0, to wireless device 2 and wireless device 4 together with the WP.

<3> indicates that wireless device 2 received data d=0 from wireless device 1 and data d=1 from wireless device 3, but based on the start counter value or timestamp transmitted and received along with the d data, it recognized that d=1 is the most recent data rather than d=0, so it sent data d=1, not d=0, to wireless device 1 and wireless device 3 together with the WP.

<4> indicates that wireless device 1 received data d=1 from wireless device 2, but based on the start counter value or timestamp transmitted and received along with the d data, it recognized that d=1 is the most recent data rather than d=0, so it transmitted data d=1 instead of d=0 to wireless device 2 together with the WP.

<5> indicates that wireless device 4 received data d=1 from wireless device 3, but based on the start counter value or timestamp transmitted and received along with the d data, it recognized that d=1 was the most recent data rather than d=0, so it sent data d=1, not d=0, to wireless device 3 together with the WP.

<6> indicates that wireless device 3 received data d=1 from wireless device 2, but recognized that d=1 was the most recent data based on the start counter value or timestamp transmitted and received along with the d data, so transmitted the data d=1 together with the WP to wireless device 2 and wireless device 4.

<7> indicates that wireless device 2 received data d=1 from wireless device 3, but recognized that d=1 was the most recent data based on the start counter value or timestamp transmitted and received along with the d data, so transmitted the data d=1 together with the WP to wireless devices 1 and 3.

FIG. 3 shows an example of transition of transmission and reception between a plurality of wireless devices in a wireless communication synchronous system according to the present invention.

In the present invention, when transmitting and receiving between a plurality of wireless devices, a mechanism is provided that does not fix the transmitting and receiving parties. In this embodiment, this mechanism is realized by the following two methods.

▲1▼
This system transmits a synchronization request signal WP and control data or collection data SIG to other radio devices at a first fixed time interval, and the other radio devices receive the synchronization request signal WP from the specific radio device at a second fixed time interval which is an interval that is an integer multiple of the first fixed time interval, thereby periodically establishing synchronization with the specific radio device. However, the time at which the synchronization request signal WP and control data or collection data SIG are transmitted at the first fixed time interval (called the WP transmission timing time) is slightly shifted randomly for each transmission timing.

When the time required to transmit the synchronization request signal WP and the control data or collection data SIG is Ams, the shift time is (Ams + αms (a margin to account for variation)) x random number value (an integer value, for example, one of 0, 1, or 2, determined randomly).

▲2▼
Furthermore, when data (data included in SIG that is intended to be shared among the radio devices; the same applies below) is updated in each radio device, the radio device promptly notifies the other radio devices of this fact. For example, the specific control procedure when using the control method based on the start counter in FIG. 1 is as follows.

Normally, each wireless device counts up at each transmission based on the received start counter, updates its own value by incrementing the received start counter value by +1, and transmits this value to other wireless devices, but when data is updated in the wireless device itself, it updates its own value by incrementing the start counter value received just before transmission by +2, and transmits this value to other wireless devices. In other words, when data is updated in the wireless device itself, it transmits a value larger than normal.

If the start counter value included in the synchronization request signal WP and data SIG satisfies the following, each wireless device accepts the SIG and performs an operation to synchronize with the timing of the transmitted synchronization request signal.
Received start counter value >= own start counter value

By doing this, when a wireless communication synchronization system consisting of multiple wireless devices is installed, the wireless device that is powered up and starts operating later will synchronize with the wireless device that started operating earlier, resulting in all the wireless devices being synchronized and data being shared.

Generally, the value of the start counter is updated to the received value +1 or +2, and this updated value is then transmitted to other radio devices. However, as mentioned above, unexpected groupings may occur for some reason, and while synchronization is achieved and data is shared within each group, synchronization may not be achieved between groups, and data may not be shared between groups.

If the groups are separated and synchronization is established within each group, this state cannot be released except by turning the power of each radio unit off and on again.

As a countermeasure to this, if there is no data update in the own radio, a random number is generated, and depending on the random number value, the value of the start counter is updated to the received value -1, rather than updating the own value to the received value +1.

For example, random numbers -1, 0, 1, 2, and 3 are generated, and when the random number value is -1, the received value is updated to -1, and otherwise the received value is updated to +1.

When the self-value is updated to the received value -1, a value counted up based on that received value -1 is transmitted to the other radio devices. Therefore, for the other radio devices in the group, a smaller value for the start counter is transmitted compared to the value they possess. As a result, they are unable to accept the synchronization request signal WP and data SIG from the radio device that transmitted the smaller value, and have an opportunity to receive the synchronization request signal WP and data SIG transmitted from another radio device outside the group.

In this way, by receiving and accepting a synchronization request signal WP and data SIG transmitted from another radio device outside the group, the grouping is released, and all radio devices within the wireless communication synchronization system are synchronized, allowing the system to return to a state in which data is shared.

▲3▼
When data is updated in each wireless device, the specific control procedure for using the control method based on the time stamp in FIG. 2 for promptly notifying other wireless devices of the update is as follows.

Normally, each radio device updates its own value with the value of the received timestamp based on the received timestamp and transmits that value to the other radio devices, but when data is updated in the radio device itself, it updates its own value with the value of the timestamp at that time and transmits that value to the other radio devices.

If the values of the time stamps included in the synchronization request signal WP and data SIG satisfy the following, each wireless device accepts the SIG and performs an operation to synchronize with the timing of the transmitted synchronization request signal.
Received timestamp value >= own timestamp value

By doing this, when a wireless communication synchronization system consisting of multiple wireless devices is installed, the wireless device that is powered up and starts operating later will synchronize with the wireless device that started operating earlier, resulting in all the wireless devices being synchronized and data being shared.

Immediately after the power is turned on and operation begins, the value of the timestamp is 0, but when data is updated in any of the radios, the timestamp of that radio becomes a value other than 0, and the other radios synchronize with the radio whose data has been updated and operate so as to share the data.

Generally, the value of the timestamp is updated to the received value, and the updated value is then sent to other wireless devices, but as mentioned above, unexpected groupings may occur for some reason, and although synchronization is achieved and data is shared within each group, synchronization may not be achieved between groups, and data may not be shared between groups. If the groups are separated and synchronization is established within each group, this state cannot be released unless the power of each wireless device is turned on again.

As a countermeasure to this, if there is no data update in the own radio, a random number is generated, and the random number value is checked, and the timestamp value is updated to the received value - 1, rather than updating the own value to the received value.

For example, a random number of -1, 0, 1, 2, or 3 is generated, and when the random number value is -1, it is updated to the received value -1, and otherwise it is updated to the received value. When the self-value is updated to the received value -1, the received value -1 is transmitted to the other wireless devices, so that the other wireless devices in the group will see a smaller value transmitted for the timestamp compared to the value they possess, and therefore will not be able to accept the synchronization request signal WP and data SIG from the wireless device that transmitted the smaller value, and will have an opportunity to receive the synchronization request signal WP and data SIG transmitted from another wireless device outside the group.

In this way, by receiving and accepting a synchronization request signal WP and data SIG transmitted from another radio device outside the group, the grouping is released, and all radio devices within the wireless communication synchronization system are synchronized, allowing the system to return to a state in which data is shared.

Figures 3 and 4 are examples showing the specific transition of which radio device each received WP+SIG from, based on the control method using the start counter in Figure 1. As mentioned above, the start counter counts up every time a WP+SIG is transmitted to another radio device, but this count-up operation is common to all radio devices in the wireless communication synchronous system and all radio devices count up synchronously, so in Figures 3 and 4, the count-up for each WP+SIG transmission is omitted.

The reason why each radio device counts up the start counter each time it transmits WP+SIG is so that the radio device that started up later can synchronize with the radio device that started up earlier. Once all radio devices in the system are synchronized and data is shared, the start counter values of all radio devices in the system will be the same.

This shows that at the time (a), wireless device 1 received (accepted) WP+SIG from wireless device 2, wireless device 2 received (accepted) WP+SIG from wireless device 3, wireless device 3 received (accepted) WP+SIG from wireless device 2, wireless device 4 received (accepted) WP+SIG from wireless device 3, wireless device 5 received (accepted) WP+SIG from wireless device 4, and wireless device 6 received (accepted) WP+SIG from wireless device 4.

At this time, with regard to the start counter value, all wireless devices receive a value of 9 from the other wireless devices and update their own value and the value to be transmitted to the other wireless devices next to the start counter value of 10. The shared data value of each wireless device is 0.

At the time (b), which is later than (a), the transmission times of the synchronization request signal WP and data SIG (the WP transmission timing time described above) sent from radio device 3 have changed randomly, which indicates that radio device 2 now receives (accepts) the WP+SIG from radio device 6 rather than from radio device 3.

At this time, all wireless devices receive the start counter value of 19 from the other wireless devices, updating their own values and the values to be transmitted next to other wireless devices to start counter = 20. The shared data value of each wireless device has not been updated, so shared data = 0 is maintained.

During the period from (b) to (c), the self-data of radio device 3 is updated from 0 to 1, so at the time of (c), radio device 3 receives the start counter value of 20 from radio device 2 at the time of the previous reception, and sets its own start counter value and the transmission value to other radio devices to 22.

All wireless devices other than wireless device 3 receive a start counter value of 20 from the other wireless devices, and set their own start counter value and the transmission value to the other wireless devices to 21. Also, at time (c), the value of the shared data held by each wireless device other than wireless device 3 remains at 0.

Then, as time progresses, at time (d), a SIG with shared data=1 has already been transmitted from wireless device 3 to wireless device 4, and the start counters of wireless device 3 and wireless device 4 become 23 and shared data=1.

Similarly, a SIG with shared data = 1 is transmitted from radio 4 to radio 5 and radio 6, then from radio 6 to radio 2, and then from radio 2 to radio 1, and as a result, the start counter and shared data held by each radio at each of times (d), (e), (f), and (g) transition as shown in Figures 3 and 4, and the shared data held by each radio ultimately becomes shared data = 1, and matches between each radio.

Next, consider a case where an unexpected grouping state occurs in this wireless communication synchronous system. At time (h), a group consisting of wireless devices 1, 2, 3, and 6, and a group consisting of wireless devices 4 and 5, are formed. At time (h), each of the former wireless devices has a start counter of 35 and shared data of 2, while each of the latter wireless devices has a start counter of 33 and shared data of 1.

Since no synchronization request signal WP or data SIG is transmitted or received between the two, the start counter and shared data values remain different between the two and cannot be matched to each other.

Therefore, in the present invention, a mechanism is provided in which a sending and receiving party is not fixed by using random numbers or the like so that a grouping state does not occur, and even if a grouping state does occur, the grouping state is quickly released and the devices are consolidated into one group.

That is, if there is no data update in the own wireless device, a random number is generated, and the random number value is checked so that the start counter value is updated not only to the received value +1, but also to the received value -1. (At time (i) in FIG. 3, the start counter value of wireless device 4 has been updated to be -1 smaller than that of wireless device 5.) The start counter value updated to the received value -1 is then transmitted to the other wireless devices.

Since the transmitted start counter value is smaller than the start counter value possessed by the other wireless devices, they cannot accept the synchronization request signal WP and data SIG from the wireless device that transmitted the received value -1, and are forced to receive a synchronization request signal and data from a wireless device other than the wireless device that transmitted the received value -1. (At time (j) in FIG. 3, wireless device 5 receives a synchronization request signal WP and data SIG from wireless device 1, which is outside the group, and the start counters and shared data of wireless devices 5 and 4 match.)

When grouping occurs, if there is a wireless device outside its own group other than the wireless device that transmitted the received value -1, the wireless device will establish synchronization and share data with the wireless device outside the group, and the grouping will naturally be dissolved. In the state of (k) in Figure 3, the grouping state is dissolved, and the shared data held by each wireless device in the system is consistent between each wireless device.

In addition to the shared data within the system, the system is also synchronized within the system. In state (h), the system is divided into two groups, and each wireless device in each group is synchronized, but there is no synchronization between the two groups. In state (k), however, all wireless devices in the system are synchronized.

FIG. 5 is a block diagram of a wireless communication synchronization system comprising a plurality of wireless devices according to the present invention.
Radio devices 1 to 6 transmit and receive a synchronization request signal WP and data SIG to each other, thereby synchronizing all radio devices in the system and sharing the same data. Since the timing of transmission and reception is synchronized between each radio device in this system, intermittent operation is possible not only during transmission but also during reception, and each radio device achieves low power consumption.

Intermittent operation is a state in which the device is usually in a sleep state, consuming almost no power, and waking up from the sleep state to operate only when necessary. For example, in the case of a transmission operation by a radio device in this system, one cycle is 250 ms, with the operation time being 1 ms and the sleep time being 249 ms.

In addition, in the system shown in FIG. 5, the wireless device 6 60 is connected to an external data recording device 70 via UART (UART TXD 71 and UART RXD 72) in order to record and store control data or collected data acquired by the entire system.

The wireless device 6 60 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 the function of converting UART format data output from the wireless device 6 60 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 wireless device 1 10, wireless device 2 20, wireless device 3 30, wireless slave device 4 40, wireless device 5 50, and wireless device 6 60 are performed in the 2.4 GHz frequency band. All of the wireless devices are powered by button batteries, except for wireless device 6, which performs UART input/output and outputs data to an external recording device. Wireless device 6 receives power from an external recording device 70.

Although it has been described above that the communication between each wireless device is performed in the 2.4 GHz frequency band, other frequency bands other than 2.4 GHz may be used. Also, in the system of Fig. 5, the frequency and address for communication between each wireless device are the same (for example, the frequency is 2450 MHz). If a system identical to the present invention exists nearby and there is a possibility of interference with that system, it is possible to deal with this by changing the frequency or address for each system.

The radio 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 radio 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 on 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 is used as various reference timers in the normal operation mode of the CPU 14 and as a timer that continues counting up even in the sleep mode to wake up from the sleep mode to the normal operation mode.

In the normal operating state of the radio device 110, both the high-speed clock 16 MHz and the low-speed clock 32.768 kHz of the CPU 14 are operating.
In the sleep mode, the high-speed 16 MHz clock of the CPU 14 is stopped, and therefore the operation of programs in the CPU 14 is also stopped, resulting in a state of low power consumption.

Even in the sleep mode, the timer count operation continues based on the low-speed clock of 32.768 kHz. 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 operation mode, and resumes the operation of the program.

After transmitting a wireless data signal to another wireless device, the CPU 14 of the wireless device 10 immediately goes into sleep mode, but after going into sleep mode, it wakes up from the sleep mode at a cycle of 250 ms.

Each of the radio devices, radio device 1 10, radio device 2 20, radio device 3 30, radio device 4 40, radio device 5 50, and radio device 6 60, transmits a synchronization request signal WP and a data SIG to the other radio devices, but the party from which each radio device receives the synchronization request signal WP and the data SIG is not determined in advance, but rather different transmission and reception timings are generated due to random numbers generated by each radio device, and the timings are determined by chance. In other words, the party from which each radio device transmits and receives the synchronization request signal WP and the data SIG is not fixed.

The SW 15 of the wireless device 110 represents an input to the CPU 14, and the SW itself is not limited to a single pole, but may be a multi-pole SW. Also, even if it is not a mechanical SW, it may be an analog sensor input such as temperature, in order to notify the CPU 14 of some information.

The CPU 14 can also take in analog sensor input as digital information using the A/D conversion function inside the CPU. The same applies to the SW25, SW35, SW45, and SW55 of the other wireless devices 2 to 5.

Also, the LED 17 of the wireless device 1 indicates an output as a result of processing by the CPU 14, and may be a buzzer or an output to the outside, not limited to an LED. The same applies to the LEDs 27, 37, 47, 57, and 67 of the other wireless devices 2 to 6.

As an example of control using SW15 to SW55 and LED17 to LED67, it is conceivable to change the duty ratio and cycle when LED17 to LED67 are turned ON/OFF according to the input values of SW15 to SW55.

For example, when there is an active input to any of SW15 to SW55, for example SW15, the cycle for turning on/off all of LEDs LED17 to LED67 changes according to that value, and all of those LEDs are turned on (lit)/off (exiled) in synchronization with a synchronization request signal WP.

Another possible control example is that if the input to SW15 becomes inactive, and there is another active input to SW25, the value of which differs from the value initially input to SW15, the ON/OFF cycle of the LEDs LED17 to LED67 will also change.

The active input values of SW15 to SW55 and the ON/OFF cycles of LED17 to LED67 are shared among wireless devices 1 to 6 by data SIG that is transmitted and received simultaneously with a synchronization request signal WP.

It is also possible to control the LEDs 17 to 67 as external outputs from each wireless device. For example, it is possible to create illumination by installing light emitters in multiple buildings or other structures outdoors at some distance from each other and synchronously turning the light emitters on and off.

Each of radio devices 1 to 6 transmits a synchronization request signal WP and a data SIG to the other radio devices, but it is uncertain and not fixed which other radio device each radio device receives the synchronization request signal WP and data SIG from.

The receivers of the synchronization request signal WP and the data SIG change from moment to moment. Fig. 5 shows the receivers of the synchronization request signal WP and the data SIG from each wireless device at a certain time.

Wireless device 1 receives WP+SIG2 101 from wireless device 2, wireless device 2 receives WP+SIG3 103 from wireless device 3, and wireless device 3 receives WP+SIG2 102 from wireless device 2. Although wireless device 1 and wireless device 3 receive WP+SIG2 from the same wireless device 2, the time when WP+SIG2 is transmitted from wireless device 2 is generally different, and the WP+SIG2 101 and WP+SIG2 102 received by wireless device 1 and wireless device 3 have different transmission times and are different.

Wireless device 4 receives WP+SIG3 104 from wireless device 3, and wireless device 5 receives WP+SIG4 106 from wireless device 4. Wireless device 6 receives WP+SIG4 105 from wireless device 4 and records the contents of SIG4 in the external data recording device 70.

6 shows the operation flow of the CPU of each wireless device in the wireless communication synchronous system of the present invention. When the power of each wireless device is turned on and the CPU of each wireless device is reset and starts operation, the wireless device first enters a continuous reception state and waits for reception of a synchronization request signal WP from another wireless device.

The RTC interval timer is an interval timer of 250 ms, and corresponds to the interval TM when the radio equipment in Figures 1 and 2 performs only transmission operations. During this interval, each radio equipment transmits a synchronization request signal WP and data SIG.

The RTC counter counts up every time the RTC interval timer expires (every time TM elapses). The RTC counter is set to 0 immediately after being reset, and is cleared to 0 every time the count value reaches 120 (every 250 ms x 120 = 30 seconds).

The radio waits for the WP in continuous reception mode until the RTC counter is <= 20 (250 ms x 20 = 5 seconds), and if the WP is not received within that time, it starts transmitting the WP itself every time the TM elapses.

If the RTC counter is not equal to 120, the wireless device will transmit the WP, then enter a sleep state, and after the TM has elapsed, will wake up from the sleep state and enter an operating state, then transmit the WP again, and repeat the process of entering the sleep state again.

When the RTC counter reaches 120 (by clearing the RTC counter to 0), the WP is received. Each wireless device receives the WP only when the RTC counter reaches 120, which means that the device repeats sleep->wake-up at 250 ms intervals, receiving WP+SIG at the wake-up timing once every 30 seconds, and only transmitting WP+SIG at the other wake-up timings.

When the RTC counter reaches 120 and a WP is received, the contents of the SIG following the WP are checked. The contents of the SIG include a start counter and shared data for each radio. The start counter is 0 immediately after a CPU reset, and continues counting thereafter, not returning to 0 until the CPU is reset.

The start counter of each wireless device counts up at the same time as the RTC counter counts up, and is updated as follows based on the start counter value received from the other wireless devices. The updated start counter value is also transmitted to the other wireless devices.

(1) After a reset or after updating the self-owned shared data, until a certain time (10 minutes) has elapsed, (a) the self start counter value = the received start counter value + 2
(2) In cases other than (1), a random number is generated, and (b) the own start counter value = the received start counter value + 1 is calculated based on the random number value.
(c) Own start counter value = received start counter value - 1

In addition, the received start counter value is accepted only if: The received start counter is greater than or equal to the value of its own start counter.

If it is not accepted, synchronization by the synchronization request signal WP will not be performed, and the shared data included in the data SIG will not be accepted, so the own shared data cannot be updated. If it is not accepted, it will receive WP+SIG from another receiver. In other words, it can be interpreted as having an opportunity to receive from another receiver.

In each radio, the start counter of the radio that started up first starts counting first, so the count value is larger, and the radio that started up later will naturally try to synchronize with the radio that started up first.

The own start counter value is randomly set to the received start counter value -1, so that the received start counter value >= the own start counter value is never satisfied.

This is done to prevent grouping from occurring within the wireless communication synchronous system, and also to quickly resolve any grouping that may occur, so that signals can be received from other receivers outside the group rather than within the group. This is a mechanism that does not fix the transmitting or receiving party between each wireless device.

In the flow of FIG. 5, a WP wait timer is described, and if the timing to receive the WP arrives and 280 ms has elapsed but the WP has not been received, the receiving operation is terminated and the transmitting operation is started.

When a WP is received, a WP cannot be received from a radio that has set its own start counter value = received start counter value - 1. Therefore, if a radio that received a WP last time sets its own start counter value = received start counter value - 1, it will not be able to receive a WP from the same radio this time.

In this case, the WP from another radio will be received at the current reception timing, or it cannot be received at the current reception timing and the reception operation will be performed again at the next reception timing. As a result, the WP may be received from a radio different from the one that was received last time. This is because the WP could not be received and the reception operation was terminated, so a new timing must be created to synchronize with the other radio.

10 Radio 1
11 Button battery 12 High-speed clock oscillator (16 MHz)
13 Low-speed clock oscillator (32.768 kHz)
14 CPU
15 SW (radio 1)
16 Radio transmission/reception circuit 17 LED (radio device 1)
20 Radio 2
25 SW (radio 2)
27 LED (radio 2)
30 Radio 3
35 SW (radio 3)
37 LED (radio 3)
40 Radio 4
45 SW (radio 4)
47 LED (radio 4)
50 Radio 5
55 SW (radio 5)
57 LED (radio 5)
60 Radio 6
67 LED (radio 6)
70 Data recording device 71 UART signal TXD
72 UART signal RXD
101 Synchronization request signal WP+SIG2 from wireless device 2 to wireless device 1
102 Synchronization request signal WP+SIG2 from wireless device 2 to wireless device 3
103 Synchronization request signal WP+SIG3 from wireless device 3 to wireless device 2
104 Synchronization request signal WP+SIG3 from wireless device 3 to wireless device 4
105 Synchronization request signal WP+SIG4 from wireless device 4 to wireless device 6
106 Synchronization request signal WP+SIG4 from wireless device 4 to wireless device 5
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: Control data or collected data SIG3: Control data or collected data SIG4: Control data or collected data SIG5: Control data or collected data α: Transmission operation (processing) time in the transmission mode of the radio

Claims (4)

A wireless communication synchronization system having a plurality of radio devices, each of which periodically exchanges synchronization request signals and data with each other, thereby establishing synchronization between the radio devices and sharing data between the radio devices; each radio device generates selection information whose value changes randomly for each radio device, and transmits this selection information together with the synchronization request signal and data; the other radio devices receive and decode the selection information , and determine whether or not to accept the synchronization request signal and data based on whether it exceeds a threshold value held by the other radio devices; and only when it is determined that the synchronization request signal and data should be accepted does it establish synchronization and accept the data; when it is determined that the data should not be accepted, it receives the selection information of other radio devices; and by controlling the transmission partner when one radio device receives to change randomly, the transmission and reception partners between the radio devices are not fixed. 2. The wireless communication synchronization system of claim 1, wherein the selection information generated by each wireless device is based on a random number generated by each wireless device. A wireless communication synchronization system having a mechanism in which the transmitting and receiving partners between the wireless devices are not fixed by the wireless devices, the wireless devices having a plurality of radio devices, each of which periodically exchanges synchronization request signals and data with each other, and each radio device controls itself so that if it receives and accepts the synchronization request signal and data transmitted from another radio device earlier than the other, it will not receive those from the other devices, and the transmission timing of the synchronization request signal transmitted by each radio device is based on the time required to transmit the synchronization request signal and data , and varies the integer value of the integer multiple so that the transmitting partner when one radio device receives changes randomly each time. 4. The wireless communication synchronization system according to claim 3, wherein the integer value of the integer multiple for varying the transmission timing of the synchronization request signal transmitted by each wireless device is based on a random number generated by each wireless device.

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