Optical communication device and control method

Abstract

One embodiment of the present invention comprises: a sleep control unit that switches the operation mode of an optical signal transmission / reception unit between an active mode, in which optical signals can be transmitted and received, and a sleep mode, in which optical signals cannot be transmitted or received; a wakeup signal reception unit that receives a wakeup signal; and a terminal data reception unit that, after a wakeup signal is received by the wakeup signal reception unit, receives data transmitted from a prescribed terminal. If a wakeup signal is received by the wakeup signal reception unit when the operation mode is the sleep mode, the sleep control unit switches the operation mode to the active mode, and the optical signal transmission / reception unit transmits data received by the terminal data reception unit to a host device, whereupon the sleep control unit switches the operation mode to the sleep mode.

Description

[Technical Field]

[0001] The present invention relates to an optical communication device and a control method. [Background technology]

[0002] When using optical power feeding to drive an optical network unit (ONU), it is difficult to supply sufficient power through optical power feeding. Therefore, in order to reduce the power consumption of the ONU, one method is to drive the ONU by periodically repeating long periods of sleep operation and short periods of active operation. In addition, there is also a case where the ONU is connected to an IoT terminal such as a weather sensor, and the IoT terminal transmits data to a higher-level device when the ONU is in active operation. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] IEEE 802.3az Energy Efficient Ethernet Summary of the Invention [Problem to be solved by the invention]

[0004] In this operation, even if data can be sent periodically, if a sudden event occurs (such as an earthquake or a dam flood), the data may not be sent immediately, making it impossible to observe the situation in real time.

[0005] In view of the above circumstances, an object of the present invention is to provide a technology that can ensure real-time performance even in an environment where it is difficult to supply sufficient power. [Means for solving the problem]

[0006] One aspect of the present invention comprises an optical signal transceiver unit that transmits and receives optical signals with a higher-level device; a sleep control unit that switches the operating mode of the optical signal transceiver unit between an active mode in which optical signals can be transmitted and received and a sleep mode in which optical signals are not transmitted and received; a wake-up signal receiving unit that receives a wake-up signal transmitted from a specified terminal; and a terminal data receiving unit that receives data transmitted from the specified terminal after the wake-up signal receiving unit receives the wake-up signal, wherein the sleep control unit switches the operating mode to the active mode when the wake-up signal receiving unit receives a wake-up signal when the operating mode is the sleep mode, and switches the operating mode to the sleep mode when the optical signal transceiver unit transmits data received by the terminal data receiving unit to the higher-level device.

[0007] One aspect of the present invention is a control method for an optical communication device comprising an optical signal transceiver unit that transmits and receives optical signals with a higher-level device, and a sleep control unit that switches the operating mode of the optical signal transceiver unit between an active mode in which optical signals can be transmitted and received and a sleep mode in which optical signals are not transmitted and received, the control method comprising: a wake-up signal receiving step that receives a wake-up signal transmitted from a specified terminal; and a terminal data receiving step that receives data transmitted from the specified terminal after the wake-up signal is received by the wake-up signal receiving step; wherein when the operating mode is sleep mode, the sleep control unit switches the operating mode to active mode when a wake-up signal is received by the wake-up signal receiving step, and switches the operating mode to sleep mode when the optical signal transceiver unit transmits data received by the terminal data receiving step to the higher-level device. [Effects of the Invention]

[0008] The present invention makes it possible to ensure real-time performance even in an environment where it is difficult to supply sufficient power. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a diagram illustrating a configuration of an optical communication system according to a first embodiment. [Figure 2] FIG. 3 is a sequence diagram showing a processing flow of the optical communication system in the first embodiment. [Figure 3] 10 is a flowchart showing the flow of processing by an ONU according to the second embodiment. [Figure 4] FIG. 10 is a diagram illustrating a configuration of an optical communication system according to a third embodiment. [Figure 5] 11 is a flowchart showing a flow of a sleeve control unit process according to the third embodiment. [Figure 6] 10 is a flowchart showing the flow of processing by an ONU according to the fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail with reference to the drawings. (First embodiment) FIG. 1 is a diagram showing the configuration of an optical communication system 1 according to the first embodiment. The optical communication system 1 is composed of an ONU 100, an OLT 200, and an IoT terminal 400. Splitters and other components provided between the ONU 100 and the OLT 200 are omitted. Of these, the ONU 100 is an example of an optical communication device according to this embodiment. The OLT 200 is an example of a higher-level device. The IoT terminal 400 is an example of a predetermined terminal. There may be multiple IoT terminals 400.

[0011] The IoT terminal 400 is a terminal that communicates with the ONU 100. In this embodiment, as an example, the IoT terminal 400 is provided with a sensor 410, and transmits and receives data indicating the sensing results of the sensor and setting data for controlling the IoT terminal 400 from the OLT 200 as a higher-level device to and from the ONU 100. When transmitting data to the higher-level device, the IoT terminal 400 transmits a wake-up signal to the ONU 100. Thereafter, when the IoT terminal 400 receives a startup notification from the ONU 100, it transmits data.

[0012] An example of data transmission by the IoT terminal 400 is when the IoT terminal 400 is equipped with a sensor that monitors the water level of a river and periodically reports the current water level or transmits data indicating that the water level has reached a dangerous level. In the following embodiments, such a trigger for the IoT terminal 400 to transmit data may be referred to as an "event." Other examples of sensors include a temperature sensor that measures air temperature and a seismometer.

[0013] The OLT 200 is a communication device provided on the central office side. The OLT 200 is composed of a communication unit 210, a data transceiver unit 220, a power supply optical transmitter unit 240, and a multiplexer / demultiplexer 230. The communication unit 210 controls the data transceiver unit 220. The data transceiver unit 220 transmits and receives data under the control of the communication unit 210. The power supply optical transmitter unit 240 outputs a signal for optical power feeding. The multiplexer / demultiplexer 230 multiplexes the optical signal transmitted from the data transceiver unit 220 with an optical signal indicating the power supply optical signal, and outputs the multiplexed signal to the ONU 100. The multiplexer / demultiplexer 230 also demultiplexes the optical signal received from the ONU 100 as necessary, and outputs the demultiplexed signal to the data transceiver unit 220.

[0014] The ONU 100 is composed of a power supply circuit unit 110, a sleep control unit 120, a multiplexer / demultiplexer 130, an optical / electrical conversion unit 150, a wake-up signal receiving unit 160, a radio unit 170, and an optical signal transmitting / receiving unit 140. The power supply circuit unit 110 is supplied with power from the optical / electrical conversion unit 150. The power supply circuit unit 110 charges a rechargeable battery 111 using the supplied power. The ONU 100 operates using the power stored in the rechargeable battery 111.

[0015] The wake-up signal receiving unit 160 receives a wake-up signal transmitted from an IoT terminal. Upon receiving the wake-up signal, the wake-up signal receiving unit 160 notifies the sleep control unit 120 that the wake-up signal has been received. The wake-up signal includes an authentication code (e.g., a preset code), and the wake-up signal receiving unit 160 performs authentication using the authentication code. If the authentication is successful, the wake-up signal receiving unit 160 notifies the sleep control unit 120 that the wake-up signal has been received. On the other hand, if the authentication is unsuccessful, the wake-up signal receiving unit 160 does not notify the sleep control unit 120 of any reception.

[0016] The wake-up signal receiving unit 160 is configured with a wake-up circuit and the like, and in this embodiment, a power-saving wake-up circuit that can operate sufficiently even with power supplied by optical power feeding is used.

[0017] The wireless unit 170 is an example of a terminal data receiving unit. The wireless unit 170 communicates wirelessly with the IoT terminal 400. The wireless unit 170 outputs data transmitted from the IoT terminal 400 to the optical signal transmitting and receiving unit 140. The wireless unit 170 transmits data output from the optical signal transmitting and receiving unit 140 addressed to the IoT terminal 400 to the IoT terminal 400. Data indicating the sensing result transmitted from the IoT terminal 400 may be referred to as "sensor data."

[0018] The optical signal transmitting and receiving unit 140 transmits and receives optical signals to and from the OLT 200. The optical signal transmitting and receiving unit 140 communicates with the IoT terminal 400. The optical signal transmitting and receiving unit 140 transmits data transmitted from the IoT terminal 400 to the OLT 200. The optical signal transmitting and receiving unit 140 transmits data received from the OLT 200 to the IoT terminal 400.

[0019] The optical signal transmitting and receiving unit 140 is composed of a communication unit 141 and a data transmitting and receiving unit 142. The communication unit 141 controls the data transmitting and receiving unit 142. The data transmitting and receiving unit 142 transmits and receives data under the control of the communication unit 141. The multiplexer / demultiplexer 130 transmits the optical signal transmitted from the data transmitting and receiving unit 142 to the OLT 200. The multiplexer / demultiplexer 130 also demultiplexes the optical signal received from the OLT 200 and outputs it to the data transmitting and receiving unit 142 and the photoelectric conversion unit 150.

[0020] The ONU 100 has an active mode in which the optical signal transmitting / receiving unit 140 can transmit and receive optical signals, and a sleep mode in which the optical signal transmitting / receiving unit 140 does not transmit and receive optical signals. The sleep control unit 120 switches between the active mode and the sleep mode.

[0021] When the operation mode is the sleep mode, the sleep control unit 120 switches the operation mode to the active mode if a wake-up signal is received by the wake-up signal receiving unit 160. At this time, the sleep control unit 120 further switches the operation mode to the sleep mode when the optical signal transmitting and receiving unit 140 transmits data received by the wireless unit 170 to the OLT 200.

[0022] In this way, even when operating in sleep mode, data from the IoT terminal 400 can be transmitted to the OLT 200, ensuring real-time performance. Furthermore, after transmitting the data, the OLT 200 returns to sleep mode, thereby reducing power consumption.

[0023] 2 is a sequence diagram showing the processing flow of the optical communication system 1 in the first embodiment. When an event occurs (step S101), the IoT terminal 400 transmits a wake-up signal to the ONU 100 (step S102). The ONU 100 performs authentication (step S103). Here, it is assumed that the authentication is successful. The ONU 100 switches to active mode (step S104) and transmits a startup notification to the IoT terminal 400 and the OLT 200 (step S105). This startup notification is a notification indicating that the ONU 100 is now able to transmit and receive data.

[0024] When the IoT terminal 400 receives the startup notification, it transmits sensor data to the ONU 100 (step S106). The ONU 100 transmits the sensor data received from the IoT terminal 400 to the OLT 200 (step S107). Thereafter, the ONU 100 switches the operation mode to a sleep mode (step S108) and ends the process.

[0025] According to the first embodiment, it is possible to ensure real-time performance and reduce power consumption.

[0026] (Second embodiment) In the second embodiment, a process of periodically switching the operation mode will be described. The configuration of the optical communication system 1 in the second embodiment is the same as that in the first embodiment, and therefore is not shown in the drawings.

[0027] 3 is a flowchart showing the processing flow of the ONU 100 according to the second embodiment. In this flowchart, the active timer and sleep timer indicate interrupts from, for example, a timer task that measures time. The active timer is a timer that indicates the timing to switch the operation mode to active mode. The sleep timer is a timer that indicates the timing to switch the operation mode to sleep mode. Furthermore, the wake-up signal interrupt is an interrupt that indicates the reception of a wake-up signal notified from the wake-up signal receiving unit 160.

[0028] 3, the sleep control unit 120 determines whether an active timer interrupt has occurred (step S201). If an active timer interrupt has occurred (step S201: YES), the sleep control unit 120 switches the operation mode to the active mode (step S202) and returns to step S201.

[0029] If an active timer interrupt has not occurred (step S201: NO), the sleep control unit 120 determines whether a sleep timer interrupt has occurred (step S203). If a sleep timer interrupt has occurred (step S203: YES), the sleep control unit 120 switches the operation mode to the sleep mode (step S204) and returns to step S201.

[0030] If a sleep timer interrupt has not occurred (step S203: NO), the sleep control unit 120 determines whether a wakeup signal interrupt has occurred (step S205). If a wakeup signal interrupt has not occurred (step S205: NO), the sleep control unit 120 returns to step S201.

[0031] If a wake-up signal interrupt occurs (step S205: YES), the sleep control unit 120 determines whether the current operation mode is the sleep mode (step S206). If the operation mode is not the sleep mode (step S206: NO), the ONU 100 performs a transfer process (step S210) and returns to step S201. Here, the "transfer process" refers to a series of processes including the startup notification (step S105) and the transfer of sensor data (steps S106 and S107) described in FIG. 2.

[0032] If the operation mode is the sleep mode in step S206 (step S206: YES), the sleeve control unit 120 switches the operation mode to the active mode (step S208). Then, the transfer process described above is performed (step S208), and the sleeve control unit 120 then switches the operation mode to the sleep mode (step S209) and returns to step S201.

[0033] In the above-described flowchart, the operation mode is switched periodically, but this period may be settable by the OLT 200. For example, if the operation time in active mode is TA and the operation time in sleep mode is TS, the pair (Ta, Ts) is notified as the setting content from the OLT 200 to the ONU 100 (hereinafter also referred to as "setting change notification"). In this case, when the time elapsed since the start of active mode becomes TA, a sleep timer interrupt occurs, and when the time elapsed since the start of sleep mode becomes TS, an active timer interrupt occurs.

[0034] According to the second embodiment, it is possible to ensure real-time performance, and also to cope with sensor data periodically transmitted from the IoT terminal 400 since the operation mode is periodically switched.

[0035] (Third embodiment) The third embodiment is an embodiment premised on a configuration in which the sleeve control unit 120 can refer to the charge amount of the rechargeable battery 111. Fig. 4 is a diagram showing the configuration of an optical communication system 1 in the third embodiment. The difference from the configuration shown in Fig. 1 is that the power supply circuit unit 110 can notify the sleeve control unit 120 of the charge amount. Other than this, the configuration is the same, so a description thereof will be omitted.

[0036] Based on the configuration shown in Fig. 4, the third embodiment will describe a mode of processing when a cycle setting is notified from the OLT 200. Fig. 5 is a flowchart showing the flow of processing by the sleeve control unit 120 according to the third embodiment. In Fig. 5, when the sleeve control unit 120 receives a setting change notification from the OLT 200 (step S301), it acquires the charge amount (step S302).

[0037] The sleeve control unit 120 determines whether or not the setting can be changed based on the charge amount (step S303). If the setting can be changed (step S303: YES), the sleeve control unit 120 sends an OK notification to the OLT 200 (step S304), changes the setting according to the setting change notification (step S305), and ends the process. Note that the "OK notification" is a notification indicating that the setting can be changed and that the setting will be changed. If the setting cannot be changed (step S303: NO), the sleeve control unit 120 sends an NG notification to the OLT 200 (step S306), and ends the process. Note that the "NG notification" is a notification indicating that the setting cannot be changed.

[0038] An example of determining whether a setting change is possible will be explained below. First, let Pa be the power consumption in active mode. Let Ps be the power consumption in sleep mode. Let the notification content of the setting change notification be (Ta, Ts). In this case, P below is the average power consumption when following the setting change notification. P = (Pa × Ta + Ps × Ts) / (Ta + Ts)

[0039] The sleeve control unit 120 may use this P to determine that it is possible to maintain a certain amount of charge even if the setting change notification is followed with the current amount of charge, and may determine that it is impossible if this is not the case.

[0040] According to the third embodiment, by maintaining a certain level of charge or more, it is possible to activate the device in response to a wake-up signal from the IoT terminal 400 and to transmit and receive sensor data at any time. Therefore, real-time performance can be ensured.

[0041] (Fourth embodiment) In the fourth embodiment, a process of switching the operation mode to active mode when the charge amount of the rechargeable battery becomes equal to or greater than a predetermined threshold will be described. Also, in the fourth embodiment, a process of switching to active mode in response to a wake-up signal in sleep mode and then continuing active mode without returning to sleep mode if the charge amount is equal to or greater than a threshold will be described. The configuration of the optical communication system 1 in the fourth embodiment is the same as that in the third embodiment, and therefore is not shown in the drawings.

[0042] Fig. 6 is a flowchart showing the flow of processing of the ONU 100 according to the fourth embodiment. In Fig. 6, the sleep control unit 120 determines whether the charge amount is equal to or greater than a threshold and whether the current operation mode is the sleep mode (step S401). If the charge amount is equal to or greater than the threshold and the current operation mode is the sleep mode (step S401: YES), the sleep control unit 120 switches the operation mode to the active mode (step S402) and returns to step S401.

[0043] If a negative determination is made in step S401 (the charge amount is less than the threshold or the current operation mode is the active mode) (step S401: NO), the sleep control unit 120 determines whether the charge amount is less than the threshold and the current operation mode is the active mode (step S403). If the charge amount is less than the threshold and the current operation mode is the active mode (step S403: YES), the sleep control unit 120 switches the operation mode to the sleep mode (step S404) and returns to step S401.

[0044] If a negative determination is made in step S403 (the charge amount is equal to or greater than the threshold value or the current operation mode is the sleep mode) (step S403: NO), the sleep control unit 120 determines whether a wake-up signal interrupt has occurred (step S405). If a wake-up signal interrupt has not occurred (step S405: NO), the sleep control unit 120 returns to step S401.

[0045] If a wake-up signal interrupt occurs (step S405: YES), the sleep control unit 120 determines whether the current operation mode is the sleep mode (step S406). If the operation mode is not the sleep mode (step S406: NO), the ONU 100 performs the above-mentioned transfer process (step S410) and returns to step S401.

[0046] In step S406, if the operation mode is the sleep mode (step S406: YES), the sleep control unit 120 switches the operation mode to the active mode (step S408). Then, the above-mentioned transfer process is performed (step S408), and then the process returns to step S403.

[0047] At the time of step S408, the device is in active mode, so when the process returns to step S403, if the charge level is less than the threshold, a positive determination is made in step S403. If a positive determination is made, the device is switched to sleep mode in step S404. Therefore, what differs from the first embodiment is that when the device is switched to active mode by a wake-up signal while in sleep mode, if the charge level of the rechargeable battery is equal to or greater than a predetermined threshold, the device maintains the active mode without switching the operating mode to sleep mode.

[0048] Therefore, the fourth embodiment basically performs the same processing as the first embodiment, but if the charge level is equal to or greater than a threshold, the active mode continues. On the other hand, in rare cases where sensor data is sent or received in a short period of time and there is a possibility that the charge level will suddenly decrease, the device can transition to sleep mode to ensure the charge level is maintained. As described above, the fourth embodiment can ensure real-time performance and can extend the time the device operates in active mode depending on the charge level compared to the first embodiment.

[0049] In the above-described embodiment, power is supplied by optical power supply, but power may be supplied by energy harvesting. Also, although the optical fiber for power supply and the optical fiber for communication are one optical fiber, they may be separate optical fibers.

[0050] The sleep control unit 120 may be configured using a processor such as a CPU (Central Processing Unit) and a memory. In this case, the sleep control unit 120 functions as the sleep control unit 120 when the processor executes a program. Note that all or part of the functions of the sleep control unit 120 may be realized using hardware such as an ASIC (Application Specific Integrated Circuit), a PLD (Programmable Logic Device), or an FPGA (Field Programmable Gate Array). The program may be recorded on a computer-readable recording medium. Examples of computer-readable recording media include portable media such as a flexible disk, a magneto-optical disk, a ROM, a CD-ROM, and a semiconductor storage device (e.g., a solid-state drive (SSD)), as well as storage devices such as a hard disk or semiconductor storage device built into a computer system. The program may be transmitted via a telecommunications line.

[0051] Although an embodiment of the present invention has been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and includes designs within the scope of the gist of the present invention. [Industrial Applicability]

[0052] The present invention is applicable to optical communication devices that operate in environments where it is difficult to supply sufficient power. [Explanation of symbols]

[0053] 1...optical communication system, 110...power supply circuit unit, 111...rechargeable battery, 120...sleep control unit, 130, 230...multiplexer / demultiplexer, 140...optical signal transmitting / receiving unit, 141, 210...communication unit, 142, 220...data transmitting / receiving unit, 150...photoelectric conversion unit, 160...wake-up signal receiving unit, 170...wireless unit, 240...power supply optical transmitting unit, 400...IoT terminal

Claims

1. an optical signal transmitting / receiving unit for transmitting and receiving optical signals to and from a higher-level device; a sleep control unit that switches the operation mode of the optical signal transmitting and receiving unit between an active mode in which an optical signal can be transmitted and received and a sleep mode in which an optical signal is not transmitted and received; a wake-up signal receiving unit that receives a wake-up signal transmitted from a predetermined terminal; a terminal data receiving unit that receives data transmitted from the predetermined terminal after the wake-up signal receiving unit receives the wake-up signal; Equipped with The sleep control unit periodically switches the operating mode based on a predetermined time, and when the operating mode periodically switched as the predetermined time elapses is sleep mode, if a wake-up signal is received by the wake-up signal receiving unit, the operating mode is switched to active mode, and when the optical signal transmitting / receiving unit transmits data received by the terminal data receiving unit to the higher-level device, the operating mode is switched to sleep mode regardless of whether the predetermined time has elapsed.

2. a power supply unit that charges a rechargeable battery using power supplied to the optical communication device; The optical communication device according to claim 1 , wherein the optical communication device operates on power stored in the rechargeable battery.

3. An optical signal transmitting / receiving unit for transmitting and receiving optical signals to and from a higher-level device; a sleep control unit that switches the operation mode of the optical signal transmitting and receiving unit between an active mode in which an optical signal can be transmitted and received and a sleep mode in which an optical signal is not transmitted and received; a wake-up signal receiving unit that receives a wake-up signal transmitted from a predetermined terminal; a terminal data receiving unit that receives data transmitted from the predetermined terminal after the wake-up signal receiving unit receives the wake-up signal; a power supply unit that charges a rechargeable battery using power supplied to the optical communication device; Equipped with the optical communication device operates using power stored in the rechargeable battery, The sleep control unit the operation mode is periodically switched, and when the periodically switched operation mode is a sleep mode, if a wake-up signal is received by the wake-up signal receiving unit, the operation mode is switched to an active mode, and when the optical signal transmitting and receiving unit transmits data received by the terminal data receiving unit to the upper device, the operation mode is switched to the sleep mode; When the higher-level device notifies the higher-level device of a change in the setting of the operating mode cycle, the optical communication device determines whether the setting can be changed based on the charge level of the rechargeable battery, and if the setting cannot be changed, notifies the higher-level device that the setting cannot be changed.

4. An optical signal transmitting / receiving unit for transmitting and receiving optical signals to and from a higher-level device; a sleep control unit that switches the operation mode of the optical signal transmitting and receiving unit between an active mode in which an optical signal can be transmitted and received and a sleep mode in which an optical signal is not transmitted and received; a wake-up signal receiving unit that receives a wake-up signal transmitted from a predetermined terminal; a terminal data receiving unit that receives data transmitted from the predetermined terminal after the wake-up signal receiving unit receives the wake-up signal; a power supply unit that charges a rechargeable battery using power supplied to the optical communication device; Equipped with the optical communication device operates using power stored in the rechargeable battery, an optical communication device characterized in that, when the operating mode is the sleep mode and the wake-up signal receiving unit receives a wake-up signal, the sleep control unit switches the operating mode to the active mode, and, after the optical signal transmitting and receiving unit transmits data received by the terminal data receiving unit to the higher-level device, if the charge level of the rechargeable battery is equal to or greater than a predetermined threshold, the sleep control unit maintains the active mode without switching the operating mode to the sleep mode.

5. 5. The optical communication device according to claim 2, wherein the power supply is supplied by power supply light transmitted from a communication destination of the optical communication device.

6. A control method for an optical communication device including an optical signal transmitting / receiving unit that transmits and receives optical signals to and from a higher-level device, and a sleep control unit that switches an operation mode of the optical signal transmitting / receiving unit between an active mode in which optical signals can be transmitted and received and a sleep mode in which optical signals are not transmitted and received, a wake-up signal receiving step of receiving a wake-up signal transmitted from a predetermined terminal; a terminal data receiving step of receiving data transmitted from the predetermined terminal after the wake-up signal is received by the wake-up signal receiving step; Equipped with The sleep control unit periodically switches the operating mode based on a predetermined time, and when the operating mode periodically switched as the predetermined time elapses is sleep mode, if a wake-up signal is received by the wake-up signal receiving step, the operating mode is switched to active mode, and when the optical signal transceiver unit transmits data received by the terminal data receiving step to the higher-level device, the operating mode is switched to sleep mode regardless of whether the predetermined time has elapsed.

7. A control method for an optical communication device comprising an optical signal transmitting / receiving unit for transmitting and receiving optical signals to and from a higher-level device, a sleep control unit for switching the operation mode of the optical signal transmitting / receiving unit between an active mode in which optical signals can be transmitted and received and a sleep mode in which optical signals are not transmitted and received, and a power supply unit for charging a rechargeable battery using power supplied to the optical communication device, a wake-up signal receiving step of receiving a wake-up signal transmitted from a predetermined terminal; a terminal data receiving step of receiving data transmitted from the predetermined terminal after the wake-up signal is received by the wake-up signal receiving step; Equipped with the optical communication device operates using power stored in the rechargeable battery, The sleep control unit the operation mode is periodically switched, and when the periodically switched operation mode is a sleep mode, if a wake-up signal is received in the wake-up signal receiving step, the operation mode is switched to an active mode, and when the optical signal transmitting and receiving unit transmits data received in the terminal data receiving step to the upper device, the operation mode is switched to the sleep mode; A control method characterized by the fact that, when the higher-level device notifies the user of a change in the setting of the operating mode cycle, the method determines whether the setting can be changed based on the charge amount of the rechargeable battery, and if the setting cannot be changed, notifies the higher-level device that the setting cannot be changed.

8. A control method for an optical communication device comprising an optical signal transmitting / receiving unit for transmitting and receiving optical signals to and from a higher-level device, a sleep control unit for switching the operation mode of the optical signal transmitting / receiving unit between an active mode in which optical signals can be transmitted and received and a sleep mode in which optical signals are not transmitted and received, and a power supply unit for charging a rechargeable battery using power supplied to the optical communication device, a wake-up signal receiving step of receiving a wake-up signal transmitted from a predetermined terminal; a terminal data receiving step of receiving data transmitted from the predetermined terminal after the wake-up signal is received by the wake-up signal receiving step; Equipped with the optical communication device operates using power stored in the rechargeable battery, a control method characterized in that, when the operation mode is the sleep mode and a wake-up signal is received in the wake-up signal receiving step, the sleep control unit switches the operation mode to the active mode, and, after the optical signal transceiver unit transmits the data received in the terminal data receiving step to the higher-level device, if the charge amount of the rechargeable battery is equal to or greater than a predetermined threshold, the operation mode is maintained in the active mode without switching to the sleep mode.

Images