Patent Description:
In recent years, wireless communication devices conducting wireless communication based on Bluetooth (registered trademark), which is a short distance wireless communication standard, have increasingly been in use.

For example, Unexamined <CIT> discloses a time correction system comprising a cell-phone device and wrist watch type terminal device conducting short distance wireless communication. In this time correction system, the cell-phone device sends time information to the wrist watch type terminal device and the wrist watch type terminal device corrects the measured time based on the time information.

Triggered by a user operation or an internal event within the cell-phone device that occurs periodically, the time information is sent and received. Moreover, the time information is sent and received again if the response time of the wrist watch type terminal device to respond with notice of completion of time adjustment since the time information is sent by the cell-phone device exceeds a given time period.

When a cell-phone device and a wrist watch type terminal device conduct short distance wireless communication as in the Unexamined <CIT>, the wrist watch type terminal device sends advertisement to the cell-phone device and the cell-phone device responds with a connection request, whereby the connection is established. Here, the advertisement is notification information for giving notice of presence of the self.

A prerequisite for realizing the transmission/reception of time information in the Unexamined <CIT> is that the connection is established as described above. Therefore, the wrist watch type terminal device has to be so programmed as to send advertisement at a timing corresponding to a user operation or an internal event that occurs periodically in the cell-phone device.

The Unexamined <CIT> describes embodiments in all of which the cell-phone device and wrist watch type terminal device deal with each other on a one-to-one basis. In other words, no embodiment is described in which the cell-phone device time-synchronizes multiple wrist watch type terminal devices.

Generally, specification for simultaneously connecting multiple wrist watch type terminals to the same cell-phone device is complex and the necessity of such a configuration is rare. Therefore, presumably, the cell-phone device in the Unexamined <CIT> is specified to establish connection to one wrist watch type terminal device at a time where there are multiple wrist watch type terminal devices to connect.

Moreover, normally, the initial value for timing transmission of advertisement for automatic time correction (the automatic time correction time) is set to the same time for all wrist watch type terminal devices. This is because even if the initial values for the timing are randomly set, the timings may overlap and some difficulty in mass production may arise.

Therefore, when the cell-phone device time-synchronizes multiple wrist watch type terminal devices in the time correction system of the Unexamined <CIT>, the timings of connection for automatic time correction of multiple wrist watch type terminal devices are set to the same time (for example, <NUM>:00AM) in some cases. In such cases, the multiple wrist watch type terminal devices send advertisement to the cell-phone device all at once at the timing of connection. However, the cell-phone device cannot establish connection to multiple wrist watch type terminal devices at the same time; therefore, unsuccessful connection occurs. As unsuccessful connection occurs, the wrist watch type terminal device is not time-synchronized. <CIT> relates to an electronic watch having a function of correcting time.

Thus, the present disclosure is made with the view of the above circumstances and an objective of the disclosure is to provide a wireless communication device and the like realizing time synchronization even where there are multiple wireless communication devices to time-synchronize.

In order to achieve the above objective, a peripheral wireless communication device and a wireless communication method are provided in accordance with independent claims <NUM> and <NUM>. Preferred embodiments are defined in claim <NUM> and claims <NUM>-<NUM>.

A more complete understanding of this application can be obtained when the following detailed description is considered in conjunction with the following drawings, in which:.

An embodiment of the present disclosure will be described hereafter with reference to the drawings. As shown in <FIG>, a wireless communication system <NUM> according to an embodiment of the present disclosure comprises a central <NUM> that is a wireless communication device, and multiple peripherals <NUM> and <NUM> that are other wireless
communication devices different from the central <NUM>.

The central <NUM> and peripherals <NUM> and <NUM> wirelessly communicate with each other based on the Bluetooth (registered trademark) low energy (the BLE, hereafter). The BLE is a standard (mode) designed for the purpose of low power consumption among the short distance wireless communication standards called Bluetooth (registered trademark).

Here, the central <NUM> provides service to the peripherals <NUM> and <NUM>. The peripherals <NUM> and <NUM> use the service provided by the central <NUM>.

The central <NUM> and peripherals <NUM> and <NUM> are each, for example, a portable terminal capable of wireless communication based on the BLE such as a cell-phone, smart-phone, tablet type personal computer, note type personal computer, and timepiece.

In this embodiment, by way of example, the central <NUM> is a smart-phone and the peripherals <NUM> and <NUM> are each an electronic timepiece receiving from the central <NUM> and displaying on a display <NUM> various data.

The configuration of the central <NUM> according to this embodiment will be described hereafter. As shown in <FIG>, the central <NUM> comprises a wireless communicator <NUM>, a read only memory (ROM) <NUM>, a random access memory (RAM) <NUM>, an operator <NUM>, a display <NUM>, and a controller <NUM>.

The wireless communicator <NUM> comprises, for example, a radio frequency (RF) circuit, base band (BB) circuit, large scale integration (LSI) circuit, or the like. The wireless communicator <NUM> sends/receives signals via an antenna <NUM> and conducts BLE-based wireless communication with the peripherals <NUM> and <NUM> that are other wireless communication devices.

The ROM <NUM> comprises a nonvolatile memory such as a flash memory and stores programs and various data (for example, timing information and/or clock rate information received from the peripherals <NUM> and <NUM>) for the controller <NUM> to control various functions.

The RAM <NUM> comprises a volatile memory and is used as the work area in which the controller <NUM> temporarily stores data for conducting various operations.

The operator <NUM> comprises a touch panel and the like, and serves as an interface used by the user for entering orders.

The display <NUM> comprises, for example, a liquid crystal display (LCD), electroluminescence (EL) display, or the like, and displays images according to image data entered from the controller <NUM>.

The controller <NUM> comprises, for example, a central processing unit (CPU). The controller <NUM> executes various programs stored in the ROM <NUM> (for example, the program for realizing the control procedure described later) to control the entire operation of the central <NUM>.

The functional configuration of the controller <NUM> of the central <NUM> is described next. The controller <NUM> functions as an advertisement receiver <NUM>, a connection request transmitter <NUM>, a timing information receiver <NUM>, a determiner <NUM>, a timing information changer <NUM>, a change notifier <NUM>, a timekeeper <NUM>, a clock signals generator <NUM>, and a disconnection request transmitter <NUM>.

The advertisement receiver <NUM> receives advertisement sent from the peripherals <NUM> and <NUM> via the antenna <NUM> and wireless communicator <NUM> based on a scan order. Here, the advertisement is notification information for the peripherals <NUM> and <NUM> to give notice of presence of themselves. A user operation for the scan order may possibly be, for example, activating an application for using service of the central <NUM>. Moreover, the scan order is not limited to a user operation and may be made periodically after the application is activated. Here, the advertisement receiver <NUM> corresponds to notification information reception means.

The connection request transmitter <NUM> sends a connection request for requesting connection of the peripherals <NUM> and <NUM> via the wireless communicator <NUM> and antenna <NUM>. The connection request is sent when the connection is necessary after the advertisement sent from the peripherals <NUM> and <NUM> is received. However, the central <NUM> cannot establish connection to multiple peripherals <NUM> and <NUM> at the same time. Therefore, the connection request is sent to either one of the multiple peripherals <NUM> and <NUM>. Here, the connection request transmitter <NUM> corresponds to connection request means.

The timing information receiver <NUM> receives timing information sent from the peripherals <NUM> and <NUM> via the antenna <NUM> and wireless communicator <NUM>. Here, the timing information is information presenting a timing of the peripheral <NUM> or <NUM> connecting to the central <NUM> and acquiring the time information from the central <NUM>. The received timing information is stored in the ROM <NUM> in association with identification information of the transmission source peripheral.

The determiner <NUM> determines whether the timing presented by the timing information received by the timing information receiver <NUM> from a peripheral (for example, the peripheral <NUM>) overlaps with the timing presented by the timing information already received from another peripheral (for example, the peripheral <NUM>).

When there is no timing information already received from another peripheral, the determiner <NUM> determines that there is no overlapped timing without the necessity of comparing the timing presented by the received timing information with the timing presented by other timing information. The determiner <NUM> determines that there is no overlapped timing when null data are received from a peripheral instead of timing information as well.

Here, the null data means empty data and are sent from a peripheral when no timing information is sent because it falls on the timing of acquiring time information. The determiner <NUM> determines that there is an overlapped timing not only when the timings are the same but also when the timings are shifted from each other by less than a given time period.

Here, the given time period is a time period set in consideration of the time required for the control procedure described later from establishment of connection to disconnection. This is set so that the time for a peripheral (for example, the peripheral <NUM>) to communicate with the central <NUM> does not overlap with the time for another peripheral (for example, the peripheral <NUM>) to communicate with the central <NUM>. Here, the determiner <NUM> corresponds to determination means.

When the determiner <NUM> determines that there is an overlapping (duplication), the timing information changer <NUM> changes the timing presented by the received timing information. The timing is changed by shifting the timing presented by the received timing information by a specific interval to a timing later than the timing presented by the timing information of another peripheral (for example, the peripheral <NUM>).

The specific interval is a time period equal to or longer than the above-mentioned given time period and, for example, two minutes. Moreover, the controller <NUM> stores the timing information having the timing changed in the ROM <NUM> in association with identification information of the transmission source peripheral (for example, the peripheral <NUM>). Here, the timing information changer <NUM> corresponds to timing information change means.

Based on the timing information changed by the timing information changer <NUM>, the change notifier <NUM> sends to the peripheral <NUM> or peripheral <NUM> that is the transmission source of that timing information notice of change to change the setting of the timing information of that peripheral <NUM> or peripheral <NUM> (namely, its own device). Here, the change notifier <NUM> corresponds to change notification means.

The timekeeper <NUM> comprises a counter circuit counting the number of pulses of clock signals of its own device (the central <NUM>). The timekeeper <NUM> measures the time based on the counted number of pulses. Moreover, the controller <NUM> executes various controls at timings based on the number of pulses counted by the timekeeper <NUM>. Here, the time measured by the timekeeper <NUM> is periodically corrected through time synchronization with a global positioning system (GPS) satellite or a base station by a not-shown time information acquirer. Here, the timekeeper <NUM> may function in a form of hardware other than the controller <NUM>.

The clock signals generator <NUM> comprises a crystal oscillator generating a reference clock, a variable phase locked loop (PLL) generating clock signals of a desired frequency from the reference clock, and the like, and generates clock signals of its own device (the central <NUM>). The frequency of the clock signals is controlled by changing the frequency dividing ratio of the variable PLL.

The disconnection request transmitter <NUM> sends a disconnection request for disconnection to the connected peripheral (the peripheral <NUM> or peripheral <NUM>) via the wireless communicator <NUM>. The disconnection request is sent, for example, when data communication with the connected peripheral ends or when the user conducts a disconnection operation. The disconnection request transmitter <NUM> corresponds to disconnection request transmission means.

The configuration of the peripherals <NUM> and <NUM> according to this embodiment is described next. Here, the peripheral <NUM> and peripheral <NUM> have the same configuration and the configuration of the peripheral <NUM> is described as their representative example. In the following explanation, the components of the peripheral <NUM> are referred to by the same reference numbers of those of the peripheral <NUM>.

As shown in <FIG>, the peripheral <NUM> comprises a wireless communicator <NUM>, a ROM <NUM>, a RAM <NUM>, an operator <NUM>, a display <NUM>, and a controller <NUM>.

The wireless communicator <NUM> comprises, for example, an RF circuit, BB circuit, LSI, or the like. The wireless communicator <NUM> conducts BLE-based wireless communication with the central <NUM> that is another wireless communication device via an antenna <NUM>.

The ROM <NUM> comprises a nonvolatile memory such as a flash memory and stores programs and data for the controller <NUM> to control various functions.

The operator <NUM> comprises buttons, switches, and the like, and serves as an interface receiving user operations.

The display <NUM> comprises, for example, an LCD, EL display, or the like, and displays images according to image data entered from the controller <NUM>.

The controller <NUM> comprises, for example, a CPU. The controller <NUM> executes various programs stored in the ROM <NUM> (for example, the program for realizing the control procedure described later) to control the entire operation of the peripheral <NUM>.

The functional configuration of the controller <NUM> of the peripheral <NUM> is described next. As shown in <FIG>, the controller <NUM> functions as an advertisement transmitter <NUM>, a connection request receiver <NUM>, a time corrector <NUM>, a timing information transmitter <NUM>, a timing setting changer <NUM>, a timekeeper <NUM>, a clock signals generator <NUM>, and a disconnection request receiver <NUM>.

The advertisement transmitter <NUM> sends advertisement to the central <NUM> via the wireless communicator <NUM> and antenna <NUM>. The advertisement is sent periodically in accordance with program processing or at the timing of a user operation occurring. Here, the advertisement transmitter <NUM> corresponds to notification information transmission means.

The connection request receiver <NUM> receives a connection request from the central <NUM> via the antenna <NUM> and wireless communicator <NUM> and establishes connection to the central <NUM>. This establishment of connection enables data communication with the central <NUM>. The connection request receiver <NUM> corresponds to connection request reception means.

The time corrector <NUM> acquires time information sent from the central <NUM> and corrects the time measured by the timekeeper <NUM> based on the time information. In other words, the time corrector <NUM> corrects the time measured in its own device (the peripheral <NUM>) so as to match the time measured in the central <NUM>. The time corrector <NUM> corresponds to time correction means.

The timing information transmitter <NUM> sends timing information to the central <NUM> via the wireless communicator <NUM> and antenna <NUM>. The timing information is information presenting a timing of its own device (the peripheral <NUM>) connecting to the central <NUM> and acquiring time information from the central <NUM>. Moreover, it is assumed that the timing presented by the timing information is stored in the ROM <NUM> as a time per day, "<NUM>:<NUM>:<NUM>" (<NUM>:00AM), in the initial state. The timing information transmitter <NUM> corresponds to timing information transmission means.

The timing setting changer <NUM> changes the setting of the timing information of its own device (the peripheral <NUM>) to timing information presenting a changed timing based on notice of change of timing information received from the central <NUM>. The timing setting changer <NUM> corresponds to timing setting change means.

The timekeeper <NUM> comprises a counter circuit counting the number of pulses of clock signals of its own device (the peripheral <NUM>). The timekeeper <NUM> measures the time based on the counted number of pulses. The time measured by the timekeeper <NUM> is corrected as appropriate by the time corrector <NUM> as described above. Moreover, the controller <NUM> executes various controls at timings based on the number of pulses counted by the timekeeper <NUM>.

The clock signals generator <NUM> comprises a crystal oscillator generating a reference clock, a variable PLL generating clock signals of a desired frequency from the reference clock, and the like, and generates clock signals of its own device (the peripheral <NUM>). The frequency of the clock signals is controlled by changing the frequency dividing ratio of the variable PLL.

The disconnection request receiver <NUM> receives a disconnection request for disconnection from the central <NUM> via the antenna <NUM> and wireless communicator <NUM>, and disconnects from the central <NUM>. The disconnection request receiver <NUM> corresponds to disconnection request reception means.

The control procedures for the central <NUM> and peripherals <NUM> and <NUM> to correct the time and change the timing information are described next with reference to <FIG>.

In the following explanation, a case in which the central <NUM> and peripheral <NUM> first execute the entire control procedures and then the central <NUM> and peripheral <NUM> execute the entire control procedures will be described. Moreover, it is assumed that no timing information of the peripherals is stored in the ROM <NUM> of the central <NUM> at the start of the control procedures. In other words, it is assumed that the first peripheral from which the central <NUM> acquires timing information is the peripheral <NUM> and the second peripheral is the peripheral <NUM>.

First, as powered on, the peripheral <NUM> starts the control procedure and enables the controller <NUM> to detect occurrence of various events. Various events occur when the user conducts given operations or at the timings of executing controls based on program processing. Here, the given user operations are, for example, an operation to pair the central <NUM> and peripheral <NUM> (initial authentication), an operation to launch a program of the peripheral <NUM>, and the like.

Here, when any of various events occurs, the controller <NUM> of the peripheral <NUM> detects the event that has occurred (Step S201). Detecting the event, the controller <NUM> of the peripheral <NUM> identifies what is the event. First, the controller <NUM> of the peripheral <NUM> determines whether the trigger of the control procedure (namely, the event) is a given user operation (Step S202).

First, the case of being determined to be a given user operation (Step S202; Yes) is entirely described. In such a case, the advertisement transmitter <NUM> of the peripheral <NUM> sends advertisement to the central <NUM>, and the connection request receiver <NUM> of the peripheral <NUM> receives a connection request from the central <NUM> and establishes connection to the central <NUM> (Step S203). On the other hand, the advertisement receiver <NUM> of the central <NUM> scans the channel of a frequency band in which the advertisement is sent to receive the advertisement sent from the peripheral <NUM>, and the connection request transmitter <NUM> of the central <NUM> sends a connection request to the peripheral <NUM> and establishes connection to the peripheral <NUM> (Step S101).

As the connection is established, the controller <NUM> of the central <NUM> notifies the peripheral <NUM> of a data request and the timing information receiver <NUM> of the central <NUM> receives timing information from the peripheral <NUM> (Step S102). On the other hand, the timing information transmitter <NUM> of the peripheral <NUM> sends timing information to the central <NUM> in response to the data request notified by the central <NUM> (Step S204). Here, it is assumed that the timing presented by the timing information is "<NUM>:<NUM>:<NUM>" stored in the ROM <NUM> of the peripheral <NUM> in the initial state.

Then, the determiner <NUM> of the central <NUM> determines whether the timing presented by the timing information received from the peripheral <NUM> overlaps with the timing presented by the timing information already received from another peripheral (Step S103).

However, as described above, no timing information is stored in the ROM <NUM> of the central <NUM> so far. Therefore, the determiner <NUM> of the central <NUM> determines that there is no overlapped timing (Step S103; No). Consequently, the timing information received from the first peripheral <NUM> is stored in the ROM <NUM> of the central <NUM> as it is.

Subsequently, the controller <NUM> (or the change notifier <NUM>) of the central <NUM> sends time information and timing information to the peripheral <NUM> (Step S105). On the other hand, the controller <NUM> of the peripheral <NUM> receives the time information and timing information sent from the central <NUM> (Step S205).

The time corrector <NUM> and timing setting changer <NUM> of the peripheral <NUM> corrects the time measured by the timekeeper <NUM> and changes the setting of the timing information based on the received time information and timing information (Step S206). However, no change was made to the timing in the timing information as described above; therefore, actually, the same timing information is overwritten.

Subsequently, the disconnection request transmitter <NUM> of the central <NUM> sends a disconnection request to the peripheral <NUM> and disconnects the peripheral <NUM> (Step S106). On the other hand, the disconnection request receiver <NUM> of the peripheral <NUM> receives the disconnection request from the central <NUM> and disconnects the central <NUM> (Step S212).

Then, the control procedures of the central <NUM> and peripheral <NUM> once end. Now, the central <NUM> is available for the control procedure with another peripheral other than the peripheral <NUM> (namely, the peripheral <NUM>).

The processing in the case of being determined to be a given user operation in the Step S202 (Step S202; Yes) is described above. The processing in the case of being determined not to be a given user operation in the Step S202 (Step S202; No) is described next.

When it is not a given user operation, the peripheral <NUM> first determines whether the current time falls on the timing presented by the timing information (connection timing) (Step S207). If it is not the connection timing (Step S207; No). The peripheral <NUM> waits for the connection timing coming.

If the current time falls on the connection timing (Step S207; Yes), the advertisement transmitter <NUM> of the peripheral <NUM> sends advertisement to the central <NUM>, receives a connection request from the central <NUM>, and establishes connection to the central <NUM> (Step S208). On the other hand, the advertisement receiver <NUM> of the central <NUM> scans the channel of a frequency band in which the advertisement is sent to receive the advertisement sent from the peripheral <NUM>, and the connection request transmitter <NUM> of the central <NUM> sends a connection request to the peripheral <NUM> and establishes connection to the peripheral <NUM> (Step S101).

As the connection is established, the timing information receiver <NUM> of the central <NUM> notifies the peripheral <NUM> of a data request and receives null data from the peripheral <NUM> (Step S102). On the other hand, the timing information transmitter <NUM> of the peripheral <NUM> sends the null data in response to the data request notified by the central <NUM> (Step S209).

However, as described above, the central <NUM> has received the null data, not timing information, from the peripheral <NUM>. Therefore, the determiner <NUM> of the central <NUM> determines that there is no overlapped timing (Step S103; No).

Subsequently, the controller <NUM> of the central <NUM> sends time information to the peripheral <NUM> (Step S105). On the other hand, the peripheral <NUM> receives the time information sent from the central <NUM> (Step S210).

The time corrector <NUM> of the peripheral <NUM> corrects the time measured by the timekeeper <NUM> based on the received time information (Step S211).

Then, the control procedures of the central <NUM> and peripheral <NUM> once end. Now, the central <NUM> is available for the control procedure with another peripheral other than the peripheral <NUM> (namely, the peripheral <NUM>). The processing in the case of being determined not to be a given user operation in the above Step S202 (Step S202; No) is described above.

The control procedures the central <NUM> and peripheral <NUM> start after the control procedures of the central <NUM> and peripheral <NUM> end are described next. For easier understanding, matters duplicated with the above-described control procedures of the central <NUM> and peripheral <NUM> are omitted in the following explanation.

First, as in the above case of the peripheral <NUM>, the controller <NUM> of the peripheral <NUM> starts the control procedure and detects various events (Step S201). As an event is detected, the controller <NUM> of the peripheral <NUM> identifies what is the event.

First, the controller <NUM> of the peripheral <NUM> determines whether the trigger of the control procedure (namely, the event) is a given user operation (Step S202).

The following explanation will be made in regard only to the case of being determined to be a given user operation (Step S202; Yes). The processing in the case of being determined not to be a given user operation (Step S202; No) is the same processing as in the above case of the peripheral <NUM> and therefore its explanation is omitted.

First, the peripheral <NUM> and central <NUM> send/receive advertisement and a connection request and establish connection as in the above case of the peripheral <NUM> (Steps S203 and S101).

As the connection is established, the controller <NUM> of the central <NUM> notifies the peripheral <NUM> of a data request and the timing information receiver <NUM> of the central <NUM> receives timing information from the peripheral <NUM> (Step S102). On the other hand, the timing information transmitter <NUM> of the peripheral <NUM> sends timing information to the central <NUM> in response to the data request notified by the central <NUM> (Step S204). Here, it is assumed that the timing presented by the timing information is "<NUM>:<NUM>:<NUM>" stored in the ROM <NUM> of the peripheral <NUM> in the initial state,.

Here, the timing information already received from the peripheral <NUM> is stored in the ROM <NUM> of the central <NUM>. Therefore, the determiner <NUM> of the central <NUM> compares the timing information of the peripheral <NUM> stored in the ROM <NUM> with the timing information received from the peripheral <NUM> this time.

As a result, the timing presented by the timing information received from the peripheral <NUM> this time is the same "<NUM>:<NUM>:<NUM>" as the timing presented by the timing information of the peripheral <NUM>. Therefore, the determiner <NUM> of the central <NUM> determines that there is an overlapped timing (Step S103; Yes).

In such a case, the timing information changer <NUM> of the central <NUM> shifts the timing presented by the timing information received from the peripheral <NUM> by the above-mentioned given time period (<NUM> minutes in this case) to change the timing from "<NUM>:<NUM>:<NUM>" to "<NUM>:<NUM>:<NUM>" (Step S104). The central <NUM> stores the changed timing information in the ROM <NUM>.

Subsequently, the controller <NUM> (or the change notifier <NUM>) of the central <NUM> sends time information and the changed timing information (notice of change) to the peripheral <NUM> (Step S105). On the other hand, the controller <NUM> of the peripheral <NUM> receives the time information and timing information (notice of change) sent from the central <NUM> (Step S205).

The time corrector <NUM> and timing setting changer <NUM> of the peripheral <NUM> corrects the time measured by the timekeeper <NUM> and changes the setting of the timing information based on the received time information and changed timing information (Step S206).

Subsequently, the disconnection request transmitter <NUM> of the central <NUM> sends a disconnection request to the peripheral <NUM>, and the disconnection request receiver <NUM> of the peripheral <NUM> receives the disconnection request from the central <NUM> and disconnects the central <NUM> (Steps S106 and S212).

Then, the control procedures of the central <NUM> and peripheral <NUM> once end. Now, the central <NUM> is available for the control procedure with another peripheral other than the peripherals <NUM> and <NUM> (none in this embodiment).

As described above, the peripherals <NUM> and <NUM> send to the central <NUM> timing information presenting a timing of acquiring time information. The central <NUM> changes the timing in the received timing information so that the timing presented by the timing information received from a peripheral (for example, the peripheral <NUM>) does not overlap with the timing presented by the already received timing information of another peripheral (for example, the peripheral <NUM>). Moreover, the central <NUM> makes the peripheral in question (for example, the peripheral <NUM>) change the setting of the timing information based on the changed timing information.

As described above, the wireless communication system <NUM> of this embodiment can prevent the timings of the peripherals <NUM> and <NUM> acquiring time information from overlapping. Consequently, it is possible to eliminate the risk of occurrence of unsuccessful connection and failed time synchronization as a result of the peripherals <NUM> and <NUM> attempting to connect to the central <NUM> and acquire time information at the same time.

Therefore, the wireless communication system <NUM> of this embodiment can realize time synchronization even if there are two peripherals (the peripherals <NUM> and <NUM>) for the central <NUM> to time-synchronize.

An embodiment is described above. The above embodiment is given by way of example. Therefore, the specific configuration and processing details of the peripherals <NUM> and <NUM> and central <NUM> are not limited to those described in the embodiment. A modified embodiment of the above embodiment is described below.

When the central <NUM> receives timing information from the peripherals <NUM> and <NUM> and the timings presented by the timing information received from the peripherals <NUM> and <NUM> overlap, the central <NUM> changes a timing by shifting the timing by a given time period or more that is set in consideration of the time required for the control procedure from establishment of connection to disconnection. The given time period is not limited to the above and may be set in consideration of clock rate information of the peripherals <NUM> and <NUM>.

For example, as a modified embodiment of the central <NUM>, a central <NUM> is configured as shown in <FIG>. A controller <NUM> of the central <NUM> has the same configuration as the controller <NUM> of the central <NUM> and additionally comprises a clock rate information receiver <NUM>. The clock rate information receiver <NUM> corresponds to clock rate information reception means. In <FIG>, the same components as of the central <NUM> are referred to by the same reference numbers.

On the other hand, as a modified embodiment of the peripherals <NUM> and <NUM>, a peripheral <NUM> is configured as shown in <FIG>. A controller <NUM> of the peripheral <NUM> has the same configuration as the controller <NUM> of the peripherals <NUM> and <NUM> and additionally comprises a clock rate information transmitter <NUM>. The clock rate information transmitter <NUM> corresponds to clock rate information transmission means. In <FIG>, the same components as of the peripherals <NUM> and <NUM> are referred to by the same reference numbers.

Between the central <NUM> and peripheral <NUM> configured as described above, the peripheral <NUM> sends clock rate information to the central <NUM> and the central <NUM> sets a given time period based on the received clock rate information. The specific interval to shift the timing for changing the timing is set to this given time period or longer. Here, the clock rate information is information presenting the deviation of the time measured by the peripheral <NUM> (namely, daily rate, monthly rate, and the like).

Even when there are multiple peripherals <NUM> for the above-described central <NUM> to time-synchronize and the times measured by the multiple peripherals vary due to time deviation as a result of the daily rate, monthly rate, and the like, the intervals between the timings in the timing information of the multiple peripherals <NUM> are specific intervals larger than the variation. Therefore, the multiple peripherals <NUM> simultaneously attempting to connect to the central <NUM> due to deviation of the times the peripherals <NUM> individually measure is certainly prevented.

In the above-described embodiment, the central <NUM> time-synchronizes two peripherals <NUM> and <NUM>. However, there may be three or more peripherals.

When there are three or more peripherals and there are two or more pieces of timing information already received in the determination of overlapped timing by the central <NUM> (Step S103), the timing is changed (Step S104) by shifting the timing by a specific interval (for example, <NUM> minutes) from the latest timing among those pieces of timing information. In other words, the settings of the timings presented by the timing information of the peripherals can be changed so that "<NUM>:<NUM>:<NUM>" is set for the first peripheral; "<NUM>:<NUM>:<NUM>," for the second peripheral; "<NUM>:<NUM>:<NUM>," for the third peripheral; and so on.

In the above-described embodiment, the timing presented by the timing information is changed to a later timing by a specific interval (for example, <NUM> minutes) when necessary. However, the timing may be changed to an earlier timing by a specific interval (for example, <NUM> minutes). Moreover, when there are three or more peripherals, the settings of the timings presented by the timing information of the peripherals may be changed so that "<NUM>:<NUM>:<NUM>" is set for the first peripheral; "<NUM>:<NUM>:<NUM>," for the second peripheral; "<NUM>:<NUM>:<NUM>," for the third peripheral; and so on. Here, the specific interval by which the timing is shifted to change is not limited to two minutes.

As described above, when the timing is shifted by a specific interval and changed either to an earlier timing or to a later timing than the timing presented by the timing information of another peripheral, there is no need of determining whether to change to an earlier timing or to a later timing at each time the timing is changed. Moreover, for a peripheral from which new timing information is received, the timing can simply be changed by shifting the timing by a specific interval always in one direction and there is no need of determining whether that timing is available. This is because shifting by an interval as small as two minutes as in the above-described embodiment allows for setting of timings of several hundred peripherals per <NUM> hours. Moreover, it is possible to change the settings of the timings in sequence without the necessity of deleting the timing information of a peripheral of which paring with the central <NUM> is canceled or taking into account a timing that accordingly becomes available. Therefore, the processing of the central <NUM> to change the timings can be simplified.

In the above-described embodiment, the central <NUM> and peripherals <NUM> and <NUM> wirelessly communicating with each other based on the BLE are used as exemplary communication devices. However, the present disclosure is not confined to a wireless communication device conducting wireless communication based on the BLE. For example, the present disclosure may be a wireless communication device conducting wireless communication based on the WiFi (registered trademark) or ZigBee (registered trademark).

Moreover, in the above-described embodiment, the determiner <NUM> determines that there is no overlapped timing when null data are received from the peripheral <NUM>. This is not restrictive. For example, the determiner <NUM> may determine that there is no overlapped timing when no timing information or null data are received within a specific time period.

Moreover, in the above-described embodiment, when the peripheral <NUM> changes the setting of the timing information based on the received timing information, substantially the same timing information is overwritten if no change is made to the timing. This is not restrictive. For example, it may be possible to continue to retain the retained timing information without overwriting substantially the same timing information.

Moreover, in the above-described embodiment, the controller <NUM>, controller <NUM>, controller <NUM>, and controller <NUM> conduct the control procedures to correct the time and change the timing information. This is not restrictive. For example, the wireless communicator <NUM> and wireless communicator <NUM> may conduct a part or all of the control procedure. In other words, the advertisement receiver <NUM>, connection request transmitter <NUM>, timing information receiver <NUM>, determiner <NUM>, timing information changer <NUM>, change notifier <NUM>, timekeeper <NUM>, clock signals generator <NUM>, disconnection request transmitter <NUM>, clock rate information receiver <NUM>, advertisement transmitter <NUM>, connection request receiver <NUM>, time corrector <NUM>, timing information transmitter <NUM>, timing setting changer <NUM>, timekeeper <NUM>, clock signals generator <NUM>, disconnection request receiver <NUM>, and clock rate information transmitter <NUM> may constitute a single controller or each individually comprise a controller to execute each operation, or the wireless communicator <NUM> and wireless communicator <NUM> may execute the operations.

Moreover, the central <NUM> and peripherals <NUM> and <NUM> according to the present disclosure may not be realized by the above device and, for example, a computer may realize the function of the central <NUM> and the function of the peripherals <NUM> and <NUM> by executing programs. The programs for realizing the function of the central <NUM> and the function of the peripherals <NUM> and <NUM> may be stored on a non-transitory computer-readable recording medium such as a universal serial bus (USB) memory, compact disc-read only memory (CD-ROM), digital versatile disc (DVD), and hard disk drive (HDD), or downloaded to a computer via a network.

Claim 1:
A peripheral wireless communication device (<NUM>, <NUM>, <NUM>) comprising a processor (<NUM>, <NUM>) configured to measure time, wherein the processor (<NUM>, <NUM>) is configured to
acquire time information from a central wireless communication device (<NUM>, <NUM>) providing service to the peripheral wireless communication device (<NUM>, <NUM>, <NUM>) and correct the measured time; characterized in that the processor (<NUM>, <NUM>) is further configured to send timing information presenting a timing of acquiring the time information to the central wireless communication device (<NUM>, <NUM>); and
when the peripheral wireless communication device (<NUM>, <NUM>, <NUM>) and another peripheral wireless communication device (<NUM>, <NUM>, <NUM>) other than the peripheral wireless communication device (<NUM>, <NUM>, <NUM>) overlap in the timing presented by the timing information, receive notice of change of the timing information from the central wireless communication device (<NUM>, <NUM>) and change a setting of the timing information based on the notice of change.