Communication device, communication system, and power feeding method

Abstract

This communication device includes: a plurality of light reception units that are connected to different power feeding light sources among a plurality of power feeding light sources for outputting power feeding light used for power feeding, and convert, into electrical power, the power feeding light output from the connected power feeding light sources; and a plurality of power supply units that supply the power, converted by each of the plurality of light reception units, to a power-supplied unit powered by the supplied power.　

Description

Communication device, communication system, and power supply method

[0001] The present invention relates to a communication device, a communication system, and a power supply method.

[0002] 5 is a configuration diagram of a conventional optically powered communication system 100. The communication system 100 includes a power supply light source 110, an optical line terminal (OLT) 120, and an optical network unit (ONU) 130. The ONU 130 is connected to both the power supply light source 110 and the OLT 120 via optical fibers. The ONU 130 transmits and receives optical signals to and from the OLT 120 to perform data communication, and is driven by optical power supplied from the power supply light source 110.

[0003] The power supply light source 110 includes a laser 111. The laser 111 outputs light of a certain wavelength as power supply light. The OLT 120 includes a communication function unit 121 and a transceiver unit 122. The communication function unit 121 generates data signals to be transmitted to the ONU 130 and receives data signals received from the ONU 130. The transceiver unit 122 converts the data signals generated by the communication function unit 121 and addressed to the ONU 130 from electrical signals to optical signals and outputs the converted signals to the optical fiber. The transceiver unit 122 receives the optical signals output from the ONU 130 and transmitted through the optical fiber, converts the received optical signals into electrical data signals, and outputs the converted signals to the communication function unit 121.

[0004] The ONU 130 includes a photoelectric conversion unit 131, a sensor 132, a transmitter / receiver 133, and a communication function unit 134. The photoelectric conversion unit 131 includes a light receiving unit 135 and a power supply unit 136. The power supply unit 136 includes a voltage conversion unit 137, a secondary battery 138, a voltage conversion unit 139, a voltage conversion unit 140, a voltage conversion unit 141, and a voltage conversion unit 142. The light receiving unit 135 converts the power supply light output from the power supply light source 110 into electric power. The voltage conversion unit 137 converts the voltage of the electric power. The secondary battery 138 stores the electric power after the voltage conversion by the voltage conversion unit 137. The voltage conversion unit 139 converts the voltage of the electric power stored in the secondary battery 138 into a common voltage.

[0005] The voltage conversion unit 140 supplies power to the transmission / reception unit 133. Therefore, the voltage conversion unit 140 converts the power after voltage conversion by the voltage conversion unit 137 into power C appropriate for use by the transmission / reception unit 133, and then supplies this power to the transmission / reception unit 133. The voltage conversion unit 141 supplies power to the communication function unit 134. Therefore, the voltage conversion unit 141 converts the power after voltage conversion by the voltage conversion unit 137 into power B appropriate for use by the communication function unit 134, and then supplies this power to the communication function unit 134. The voltage conversion unit 142 supplies power to the sensor 132. Therefore, the voltage conversion unit 142 converts the power after voltage conversion by the voltage conversion unit 137 into power A appropriate for use by the sensor 132, and then supplies this power to the sensor 132.

[0006] H. Katsurai et al., “Sleep / Active operation of optical-power-supplied ONU without electricity for rural IoT,” 2022 International Conference on Emerging Technologies for Communications (ICETC 2022). Kensuke Ikeda, “Development of an electrically isolated antenna system using optical fiber to improve the lightning resistance of wireless equipment,” IEICE Transactions on Electronics, Information and Communication Engineers, Vol. J105-B, No. 11, pp. 895-903, Nov. 2022.

[0007] As described above, the ONU 130, which is driven by optical power supplied from the power supply light source 110, needs to efficiently secure power. However, when supplying power to a conventional ONU 130 with multiple power supply voltages, the power must first be converted to a common voltage and then converted again. This results in a large energy loss due to the voltage conversion section, making it difficult to efficiently secure power.

[0008] In view of the above circumstances, an object of the present invention is to provide a technology that can reduce energy loss and efficiently secure electric power.

[0009] One aspect of the present invention is a communication device that includes a plurality of light receiving units that are connected to different power supply light sources among a plurality of power supply light sources that output power supply light used for power supply, and that convert the power supply light output from the connected power supply light sources into electric power, and a plurality of power supply units that supply the electric power converted by each of the plurality of light receiving units to a power supply unit that operates by power supply.

[0010] One aspect of the present invention is a communication system comprising a plurality of power supply light sources that output power supply light used for power supply, and a communication device, wherein the communication device comprises a plurality of light receiving units that are connected to different power supply light sources among the plurality of power supply light sources and convert the power supply light output from the connected power supply light sources into electric power, and a plurality of power supply units that supply the electric power converted by each of the plurality of light receiving units to a power supply unit that operates by power supply.

[0011] One aspect of the present invention is a power supply method in which a plurality of light receiving units connected to different power supply light sources among a plurality of power supply light sources that output power supply light used for power supply convert the power supply light into electricity, and the converted electricity is supplied from a plurality of power supply units to a power-receiving unit that operates by power supply.

[0012] According to the present invention, it is possible to reduce energy loss and efficiently secure electric power.

[0013] Fig. 1 is a configuration diagram of a communication system according to a first embodiment. Fig. 2 is a sequence diagram for explaining the flow of processing in the communication system according to the first embodiment. Fig. 3 is a diagram showing an example of the configuration of an ONU according to a second embodiment. Fig. 4 is a configuration diagram of a communication system according to a third embodiment. Fig. 5 is a configuration diagram of a conventional communication system driven by optical power feeding.

[0014] An embodiment of the present invention will be described below with reference to the drawings. (First Embodiment) Fig. 1 is a configuration diagram of a communication system 1 in the first embodiment. The communication system 1 includes a plurality of power supply light sources 2, an OLT 3, and ONUs 4. The power supply light sources 2 and the ONUs 4 are connected by optical fiber 5, and the OLT 3 and the ONUs 4 are connected by optical fiber 6. The ONUs 4 are an example of a communication device, and the optical fibers 5 and 6 are examples of optical transmission paths. Fig. 1 shows an example in which there are three power supply light sources 2.

[0015] In the following description, the three power supply light sources 2 will be referred to as power supply light sources 2a, 2b, and 2c, respectively. The number of power supply light sources 2 is not limited to three, as long as there are two or more. The optical fiber 5 between the power supply light source 2x (x = a, b, c) and the ONU 4 will be referred to as the optical fiber 5x. In the following description, when there is no need to particularly distinguish between the power supply light sources 2a, 2b, and 2c, they will be referred to as the power supply light source 2. In FIG. 1, the solid line connecting the power supply light source 2 and the ONU 4 indicates power supply light, the dotted line in FIG. 1 indicates power, and the dashed-dotted line in FIG. 1 indicates data communication, and the same applies to the following embodiments.

[0016] The power supply light source 2 includes a laser 21. The wavelengths of the lasers 21 of the power supply light sources 2 may be the same or different as long as they are within a range that can be received by the light receiving unit of the ONU 4. The power supply light source 2 inputs the light output from the laser 21 into the optical fiber 5 as power supply light.

[0017] The OLT 3 includes a communication function unit 31 and a transceiver unit 32. The communication function unit 31 generates data signals to be transmitted to the ONUs 4 and receives data signals received from the ONUs 4. The transceiver unit 32 converts the data signals generated by the communication function unit 31 and addressed to the ONUs 4 from electrical signals to optical signals and outputs the converted signals to the optical fiber 6. The transceiver unit 32 also receives optical signals output from the ONUs 4 and transmitted through the optical fiber 6, converts the received optical signals into electrical data signals, and outputs the converted signals to the communication function unit 31.

[0018] The ONU 4 includes a photoelectric conversion unit 41, a sensor 42, a transceiver unit 43, and a communication function unit 44. The sensor 42, the transceiver unit 43, and the communication function unit 44 are powered units that operate with power supplied from the power supply unit 422. Note that the ONU 4 may include other powered units that operate with power supplied from the power supply unit 422, in addition to the sensor 42, the transceiver unit 43, and the communication function unit 44. The transceiver unit 43 and the communication function unit 44 are examples of communication units.

[0019] The photoelectric conversion unit 41 includes a plurality of light receiving units 411 and a plurality of power supply units 412. The number of light receiving units 411 and power supply units 412 is the same as the number of power supply light sources 2. FIG. 1 shows an example in which there are three light receiving units 411 and three power supply units 412. The light receiving unit 411-1 is connected to the power supply light source 2a via an optical fiber 5a, the light receiving unit 411-2 is connected to the power supply light source 2b via an optical fiber 5b, and the light receiving unit 411-3 is connected to the power supply light source 2c via an optical fiber 5c. In this way, the photoelectric conversion unit 41 includes light receiving units 411 that are connected to the power supply light source 2 via independent paths.

[0020] The light receiving unit 411 converts the power supply light output from the power supply light source 2 into electric power. The power supply unit 412 stores the electric power converted by the light receiving unit 411 and supplies the stored electric power to the power-supplied units that are individually connected to it. For example, the power supply unit 412-1 supplies electric power to the sensor 42, the power supply unit 412-2 supplies electric power to the communication function unit 44, and the power supply unit 412-3 supplies electric power to the transceiver unit 43. Note that the connection relationship shown in FIG. 1 is an example, and each power supply unit 412 may be connected to any of the function units.

[0021] The power supply unit 412 includes a voltage conversion unit 413 and a secondary battery 414. The voltage conversion unit 413 converts the power obtained by the light receiving unit 411 into a voltage suitable for storage. The secondary battery 414 stores the power after voltage conversion. The secondary battery 414 supplies the stored power to each unit, such as the sensor 42, the transmitting / receiving unit 43, and the communication function unit 44.

[0022] The sensor 42 detects a physical quantity. The sensor 42 outputs the detected physical quantity as a data signal to the communication function unit 44. The transceiver 43 receives an optical signal output from the OLT 3 and transmitted through the optical fiber 6, converts the received optical signal into an electrical data signal, and outputs the data signal to the communication function unit 44. Furthermore, the transceiver 43 converts the data signal generated by the communication function unit 44 and addressed to the OLT 3 from an electrical signal to an optical signal, and outputs the data signal to the optical fiber 6. The communication function unit 44 performs a reception process for the data signal converted into an electrical signal by the transceiver 43. Furthermore, the communication function unit 44 performs a generation process for the data signal, and outputs the generated data signal addressed to the OLT 3 to the transceiver 43.

[0023] 2 is a sequence diagram illustrating the processing flow of the communication system 1 according to the first embodiment. The laser 21 of each power supply light source 2 outputs power supply light of a certain wavelength to the optical fiber 5 (step S101). For example, the laser 21 of the power supply light source 2a outputs power supply light of wavelength A to the optical fiber 5a, the laser 21 of the power supply light source 2b outputs power supply light of wavelength B to the optical fiber 5b, and the laser 21 of the power supply light source 2c outputs power supply light of wavelength C to the optical fiber 5c.

[0024] The power supply light output from each power supply light source 2 is input to the ONU 4 via the optical fiber 5. The light receiving unit 411 of the ONU 4 receives the power supply light transmitted via the optical fiber 5 (step S102). The light receiving unit 411-1 receives the power supply light of wavelength A transmitted via, for example, the optical fiber 5a and converts the power supply light into electric power (step S103). The light receiving unit 411-1 outputs the converted electric power to the power supply unit 412-1. The light receiving unit 411-2 receives the power supply light of wavelength B transmitted via, for example, the optical fiber 5b and converts the power supply light into electric power. The light receiving unit 411-2 outputs the converted electric power to the power supply unit 412-2. The light receiving unit 411-3 receives the power supply light of wavelength C transmitted via, for example, the optical fiber 5c and converts the power supply light into electric power. The light receiving unit 411-3 outputs the converted power to the power supply unit 412-3.

[0025] The power supply unit 412 stores the power output from the light receiving unit 411 (step S104). The voltage conversion unit 413-1 of the power supply unit 412-1 converts the voltage of the power output from the light receiving unit 411-1 and then stores the power in the secondary battery 414-1. The voltage conversion unit 413-2 of the power supply unit 412-2 converts the voltage of the power output from the light receiving unit 411-2 and then stores the power in the secondary battery 414-2. The voltage conversion unit 413-3 of the power supply unit 412-3 converts the voltage of the power output from the light receiving unit 411-3 and then stores the power in the secondary battery 414-3.

[0026] The power supply unit 412 supplies power to the sensor 42, the transmitter / receiver 43, and the communication function unit 44 (step S105). The secondary battery 414-1 of the power supply unit 412-1 supplies, for example, stored power to the sensor 42. The secondary battery 414-2 of the power supply unit 412-2 supplies, for example, stored power to the communication function unit 44. The secondary battery 414-3 of the power supply unit 412-3 supplies, for example, stored power to the transmitter / receiver 43. This enables the sensor 42, the transmitter / receiver 43, and the communication function unit 44 to operate.

[0027] The sensor 42 detects a physical quantity (step S106). The sensor 42 outputs the detected physical quantity as a data signal to the communication function unit 44. The communication function unit 44 generates an electrical signal for data communication using the data signal output from the sensor 42 (step S107). The communication function unit 44 outputs the generated electrical signal for data communication to the transmission / reception unit 43. The transmission / reception unit 43 converts the electrical signal for data communication generated by the communication function unit 44 into an optical signal and transmits the optical signal to the optical fiber 6 (step S108).

[0028] The transmitter / receiver 32 of the OLT 3 receives the optical signal transmitted from the ONU 4 (step S109). The transmitter / receiver 32 converts the received optical signal into an electrical signal and outputs it to the communication function unit 31. The communication function unit 31 performs reception processing of the electrical signal output from the transmitter / receiver 32 (step S110). For example, the communication function unit 31 acquires a data signal from the electrical signal output from the transmitter / receiver 32.

[0029] According to the communication system 1 configured as described above, the photoelectric conversion unit 41 in the ONU 4 is provided with a plurality of light receiving units 411 and a power supply unit 412. This allows the power supply light output from a plurality of different power supply light sources 2 to be received and power to be supplied to each powered unit individually. In this way, the power supply light output from a plurality of different power supply light sources 2 can be converted into electricity by each light receiving unit 411 and supplied, thereby reducing energy loss and efficiently securing power.

[0030] Furthermore, since power can be supplied from a plurality of different power supply light sources 2, it becomes possible to operate devices that consume a large amount of power.

[0031] (Second embodiment) In the second embodiment, a configuration will be described in which power is converted into a plurality of required voltages within the OLT and supplied to the power-supplied units. In the second embodiment, the configuration of the communication system 1 is the same as in the first embodiment. In the second embodiment, the configuration of the ONU differs from that of the first embodiment. The following description will focus on the differences from the first embodiment.

[0032] 3 is a diagram showing an example of the configuration of an ONU 4a in the second embodiment. The ONU 4a includes a photoelectric conversion unit 41a, a sensor 42, a transmitter / receiver 43, and a communication function unit 44. The photoelectric conversion unit 41a includes a plurality of light receiving units 411 and a plurality of power supply units 412a. The number of light receiving units 411 and power supply units 412a is the same as the number of power supply light sources 2. FIG. 3 shows an example in which there are three light receiving units 411 and three power supply units 412a.

[0033] The power supply unit 412a converts the power supply light into multiple types of power supply voltages required within the ONU 4 and supplies the required power supply voltages to the powered units. The power supply units 412a-1, 412a-2, and 412a-3 supply different power supply voltages. The power supply unit 412a includes a voltage conversion unit 413, a secondary battery 414, and a voltage conversion unit 415. The voltage conversion unit 413 converts the power obtained by the light receiving unit 411 into a voltage suitable for storage. The secondary battery 414 stores the power after voltage conversion. The voltage conversion unit 415 converts the power stored in the secondary battery 414 into a predetermined voltage and supplies it to the powered units.

[0034] For example, voltage conversion unit 415-1 converts the power stored in secondary battery 414-1 to voltage A and supplies it to the powered units. For example, voltage conversion unit 415-2 converts the power stored in secondary battery 414-2 to voltage B and supplies it to the powered units. For example, voltage conversion unit 415-3 converts the power stored in secondary battery 414-3 to voltage C and supplies it to the powered units. Voltages A, B, and C are all different voltages. Different components receive power for each voltage. FIG. 3 shows, as an example, a case where voltages A and B are voltages that can be supplied to each powered unit, and voltage C is a voltage that can be supplied to transmitter / receiver 43. In this way, voltage conversion unit 415 may convert the voltage into a voltage that can be supplied to all powered units, or may convert into a voltage that can be supplied to a specific powered unit.

[0035] According to the communication system 1 of the second embodiment configured as described above, a voltage suitable for the power-receiving unit can be supplied with a small number of conversions, thereby reducing energy loss.

[0036] Third Embodiment In a third embodiment, a configuration for switching the power supply source that supplies power to a power-received unit will be described.

[0037] Fig. 4 is a configuration diagram of a communication system 1b according to the third embodiment. The communication system 1b includes a plurality of power supply light sources 2, an OLT 3, and an ONU 4b. The power supply light sources 2 and the ONU 4b are connected by an optical fiber 5, and the OLT 3 and the ONU 4b are connected by an optical fiber 6. The ONU 4b is an example of a communication device, and the optical fibers 5 and 6 are examples of optical transmission paths. Fig. 4 shows an example in which four power supply light sources 2 are used.

[0038] In the following description, the four power supply light sources 2 will be referred to as power supply light sources 2a, 2b, 2c, and 2d, respectively. The optical fiber 5 between the power supply light source 2x (x=a, b, c, d) and the ONU 4b will be referred to as the optical fiber 5x. In the following description, when there is no need to particularly distinguish between the power supply light sources 2a, 2b, 2c, and 2d, they will be referred to as the power supply light sources 2.

[0039] The processing of the third embodiment differs from that of the first embodiment in the ONU 4b. Therefore, the following description will focus on the configuration of the ONU 4b. The ONU 4b includes a photoelectric conversion unit 41b, a sensor 42, a transceiver unit 43, a communication function unit 44, and a switching circuit 45. The switching circuit 45 is provided between a plurality of power supply units 412 and the power-receiving units. In the example shown in FIG. 4, the switching circuit 45 is provided between the power supply units 412-1 and 412-2 and the sensor 42. The switching circuit 45 is configured using a voltage detection circuit or the like. The switching circuit 45 detects when the input voltage falls below a threshold, and switches the power supply unit 412 that supplies power to another power supply unit 412.

[0040] 4, the switching circuit 45 is connected to the sensor 42, providing a redundant power supply source for the sensor 42, but the redundant configuration is not limited to the one for the sensor 42. The switching circuit 45 may be applied to all or part of the transmitting / receiving unit 43 and the communication function unit 44.

[0041] The photoelectric conversion unit 41b includes a plurality of light receiving units 411 and a plurality of power supply units 412. The number of light receiving units 411 and power supply units 412 is the same as the number of power supply light sources 2. FIG. 4 shows an example in which there are four light receiving units 411 and four power supply units 412. The light receiving unit 411-1 is connected to the power supply light source 2a via optical fiber 5a, the light receiving unit 411-2 is connected to the power supply light source 2b via optical fiber 5b, the light receiving unit 411-3 is connected to the power supply light source 2c via optical fiber 5c, and the light receiving unit 411-4 is connected to the power supply light source 2d via optical fiber 5d. In this way, the photoelectric conversion unit 41b includes light receiving units 411 that are connected to the power supply light source 2 via independent paths.

[0042] The power supply unit 412 stores the power converted by the light receiving unit 411 and supplies the stored power to the power-receiving units that are individually connected to it. For example, the power supply units 412-1 and 412-2 supply power to the sensor 42 via the switching circuit 45, the power supply unit 412-3 supplies power to the communication function unit 44, and the power supply unit 412-4 supplies power to the transmitter / receiver 43. Note that the connection relationship shown in FIG. 4 is an example, and each power supply unit 412 may be connected to any of the function units.

[0043] 4, it is assumed that the sensor 42 is connected to a power supply unit 412-1 via a switching circuit 45. When the switching circuit 45 detects that the voltage of the power output from the power supply unit 412-1 is less than a threshold value, the switching circuit 45 switches the power supply source from the power supply unit 412-1 to the power supply unit 412-2. In other words, the switching circuit 45 switches the connection between the power supply unit 412-1 and the sensor 42 so that the power supply unit 412-2 and the sensor 42 are connected.

[0044] The communication system 1b configured as described above can achieve the same effects as the first embodiment. Furthermore, the communication system 1b includes a switching circuit 45 that switches the power supply source. This allows the power supply source to be switched to another power supply unit 412 when the voltage of the power supplied from the power supply unit 412 connected to the powered unit drops. As a result, it is possible to supply a higher power than before the switch.

[0045] (Variation 1 common to the first to third embodiments) In each of the above embodiments, the case where the ONUs 4, 4a, and 4b perform data communication with the OLT 3 using optical signals has been described, but the communication systems 1 and 1b can also be applied to a case where a communication device and a second communication device perform data communication using electrical signals, wireless signals, etc. instead of the ONUs 4, 4a, and 4b and the OLT 3. In this case, the transceiver 43 and the transceiver 32 transmit and receive electrical signals, wireless signals, etc.

[0046] (Variant 2 common to the first to third embodiments) In each of the above embodiments, a configuration was shown in which the ONU 4 is equipped with a secondary battery 414, assuming that the sensor 42 etc. will perform intermittent operation. However, if the ONU 4 supplies the power obtained by the light receiving unit 411 directly to the power supply unit, the ONU 4 does not need to be equipped with a secondary battery 414.

[0047] (Modification 3 common to the first to third embodiments) In each of the above embodiments, the ONU 4 is configured to include the sensor 42, but the sensor 42 may be provided outside the ONU 4. In such a configuration, the ONU 4 includes a wireless communication unit that is wirelessly connected to the sensor 42. In this case, the wireless communication unit is a power-receiving unit, and may receive power from any of the power supply units 412.

[0048] 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.

[0049] The present invention can be applied to a system that performs optical power feeding.

[0050] REFERENCE SIGNS LIST 1, 1b... communication system, 2, 2a, 2b, 2c, 2d... power supply light source, 3... OLT, 4, 4a, 4b... ONU, 21... laser, 31, 44... communication function unit, 32, 43... transmitting / receiving unit, 45... switching circuit, 41, 41a, 41b... photoelectric conversion unit, 42... sensor, 411, 411-1 to 411-4... light receiving unit, 412, 412-1 to 412-4... power supply unit, 413, 413-1 to 413-4, 415-1 to 415-3... voltage conversion unit, 414, 414-1 to 414-4... secondary battery

Claims

1. A communications device comprising: a plurality of light receiving units that are connected to different power supply light sources among a plurality of power supply light sources that output power supply light used for power supply, and that convert the power supply light output from the connected power supply light sources into electric power; and a plurality of power supply units that supply the electric power converted by each of the plurality of light receiving units to a powered unit that operates by power supply.

2. The communication device described in claim 1, wherein each of the multiple power supply units includes a first voltage conversion unit and a secondary battery, the first voltage conversion unit converts the voltage of the power converted by each of the multiple light receiving units, and the secondary battery stores the power whose voltage has been converted by the first voltage conversion unit and supplies it to the power supplied unit.

3. The communication device according to claim 2, wherein each of the plurality of power supply units further comprises a second voltage conversion unit downstream of the secondary battery, and the second voltage conversion unit included in each of the plurality of power supply units converts the voltage of the power stored in the secondary battery into voltages different from each other.

4. The communication device according to any one of claims 1 to 3, further comprising one or more switching circuits provided between the plurality of power supply units and the powered unit, for switching a power supply source.

5. The communication device described in claim 4, wherein the one or more switching circuits are connected to a first power supply unit and a second power supply unit among the multiple power supply units and to the powered unit, and when it is detected that the voltage of the power supplied from the first power supply unit has fallen below a threshold value while power supplied from the first power supply unit is being supplied to the powered unit, the switching circuits switch the connection so that power supplied from the second power supply unit is supplied to the powered unit.

6. A communication system comprising: a plurality of power supply light sources that output power supply light used for power supply; and a communication device, wherein the communication device comprises: a plurality of light receiving units that connect to different power supply light sources among the plurality of power supply light sources and convert the power supply light output from the connected power supply light sources into electric power; and a plurality of power supply units that supply the electric power converted by each of the plurality of light receiving units to a power-receiving unit that operates by power supply.

7. A power supply method in which a plurality of light receiving units each connected to a different one of a plurality of power supply light sources that output power supply light used for power supply convert the power supply light into electric power, and the converted electric power is supplied from a plurality of power supply units to a power-receiving unit that operates by power supply.

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