Node device, transmission system, and abnormality detection method

Abstract

To provide a node device, a transmission system, and an abnormality detection method capable of detecting, with a simple configuration, an abnormality in a photoelectric conversion unit that converts an optical video signal into an electrical video signal.SOLUTION: A node device 10 includes: a photoelectric conversion unit 31 that converts an optical video signal input via an FTTH optical transmission line 5 to an electrical video signal and outputs the electrical video signal; a D-ONU 33 (data communication unit) that establishes a link connection with an OLT 22 (external device); and a power supply unit 34 that supplies power to both the photoelectric conversion unit 31 and the D-ONU 33.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a node device, a transmission system, and an abnormality detection method for converting an optical video signal into an electrical video signal.

Background Art

[0002] Conventionally, a technique is known in which an optical video signal transmitted using an optical transmission line is converted into an electrical video signal and the video is transmitted to a user's video viewing equipment. Patent Document 1 and Patent Document 2 describe this type of technique.

[0003] Patent Document 1 relates to a monitoring device that monitors the state of an electrical video signal output from a V-ONU that converts an optical video signal into an electrical video signal. Patent Document 1 describes supplying state information indicating the state of the electrical video signal output from the V-ONU to a D-ONU that mutually converts an optical data signal and an electrical data signal, and transmitting it to a center device via the D-ONU.

[0004] Patent Document 2 relates to a cable television system having a node device connected to a center device via an optical transmission line and a plurality of terminal devices connected to the node device. Patent Document 2 describes that the node device transmits the operating state of the HFC function unit or the FTTH function unit to the center device according to the mounting state of the detachably configured HFC function unit and FTTH function unit.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] The optical video signal transmitted from the optical transmitter of the center device is transmitted via an optical transmission line to a node device that converts the optical video signal into an electrical video signal. This type of optical transmission line for video transmission has hitherto been carried out using an HFC transmission line for the exchange of downstream and upstream signals between the center device and the node device. However, it is necessary to arrange node devices and electrical video signal amplifiers that require multiple power supplies in the transmission line, and there are problems in terms of operation such as lightning protection and maintenance.

[0007] In recent years, with the popularization of FTTH transmission lines that can transmit up to subscriber homes via optical transmission lines and do not include devices that require power supply in the transmission line, the shift from HFC transmission lines to FTTH transmission lines has been progressing. However, there is a problem that the migration to FTTH transmission lines up to subscriber homes cannot be completed due to reasons such as the existence of a certain number of subscribers who continue to use video services via HFC transmission lines and do not actively desire services via FTTH transmission lines. To solve this problem, for example, there is a demand for a system that can transmit an optical video signal via an FTTH transmission line up to the vicinity of the subscriber's home, convert it into an electrical video signal using a dedicated node device, and provide a video service via a coaxial cable that is also part of the HFC transmission line up to the subscriber's home. In this video transmission system, since the optical video signal is only in the downstream direction between the center device and the node device, there is no means to notify the center device side of an abnormality in the node device. For example, even if the power supply of the node device stops, the center device side cannot grasp this fact.

[0008] Thus, while there is a desire to grasp the power supply state of the node device even on the center side, since the node device is also used near the subscriber's home etc., the required number is large, and it is necessary to make it as small and inexpensive as possible. There was a problem that the state had to be notified to the center side with a configuration as simple as possible. In Patent Document 2, since the device at the stage before converting the optical video signal into an electrical video signal is the monitoring target, an abnormality in the part that converts the optical video signal into an electrical video signal cannot be detected. In the technique described in Patent Document 1, the state of the electrical video signal output from the V-ONU is monitored and transmitted to the center device via the D-ONU. However, in addition to the functional unit that converts the optical video signal into an electrical video signal and the D-ONU, it is necessary to mount a monitoring device that monitors the state of the electrical video signal, and there was room for improvement in providing a small, inexpensive, and low-power consumption node device.

[0009] An object of the present invention is to provide a node device, a transmission system, and an abnormality detection method that can detect an abnormality in an optoelectronic conversion unit that converts an optical video signal into an electrical video signal with a simple configuration in order to realize a small and inexpensive node device.

Means for Solving the Problems

[0010] The present invention relates to a node device including an optoelectronic conversion unit that converts an optical video signal input via an optical transmission path into an electrical video signal and outputs it, a data communication unit that establishes a link connection with an external device, and a power supply unit that supplies power to both the optoelectronic conversion unit and the data communication unit.

[0011] The node device may be configured such that when the supply of power from the power supply unit is stopped, the link connection between the data communication unit and the external device is lost.

[0012] The node device may be configured such that when the power supply voltage supplied from the power supply unit decreases, the link connection between the data communication unit and the external device is lost.

[0013] The node device further includes a detection unit that detects an abnormality in at least one of the photoelectric conversion unit and the power supply unit, and the link connection between the data communication unit and the external device may be lost based on an abnormality signal indicating the abnormality from the detection unit.

[0014] The data communication unit has an input unit that stops the optical output. When the abnormality signal from the detection unit is input to the input unit, the optical output from the data communication unit is stopped, and the link connection between the data communication unit and the external device may be lost.

[0015] The node device further includes an electrical signal amplification unit that amplifies the electrical video signal output from the photoelectric conversion unit, and the power supply unit may supply power to the photoelectric conversion unit, the electrical signal amplification unit, and the data communication unit.

[0016] The node device further includes an electrical signal amplification unit that amplifies the electrical video signal output from the photoelectric conversion unit. The detection unit detects an abnormality in the electrical signal amplification unit, and the link connection between the data communication unit and the external device may be lost based on an abnormality signal indicating the abnormality in the electrical signal amplification unit.

[0017] The node device further includes an information processing unit that acquires state information indicating the state of at least one of the photoelectric conversion unit and the power supply unit. The information processing unit may execute a process of transmitting the state information to the external device via the data communication unit.

[0018] The node device further includes an electrical signal amplification unit that amplifies the electrical video signal output from the photoelectric conversion unit. The information processing unit acquires state information indicating the state of the electrical signal amplification unit, and may execute a process of transmitting the state information to the external device via the data communication unit.

[0019] Furthermore, the present invention relates to a transmission system including the node device and an optical transmission path that transmits an optical video signal input to the node device.

[0020] The present invention also relates to a transmission system including the node device and a coaxial cable transmission line that transmits an electrical video signal output from the node device.

[0021] The present invention also relates to an abnormality detection method including: a power supply step of supplying power to both a photoelectric conversion unit that converts an optical video signal into an electrical video signal and outputs the converted signal, and a data communication unit that establishes a link connection with an external device, by a power supply unit; a signal conversion step of converting an optical video signal input via an optical transmission line by the photoelectric conversion unit into an electrical video signal and outputting the converted signal; a connection step of establishing a link connection between the data communication unit and the external device; and an abnormality detection step of detecting that an abnormality has occurred based on the loss of the link connection between the data communication unit and the external device.

Advantages of the Invention

[0022] According to the present invention, it is possible to provide a node device, a transmission system, and an abnormality detection method that can detect an abnormality in a photoelectric conversion unit that converts an optical video signal into an electrical video signal with a simple configuration. Thereby, for example, in a system in which an optical video signal is transmitted through an FTTH transmission line to the vicinity of a subscriber's home, converted into an electrical video signal by a node device, and a video service is provided to the subscriber's home via a coaxial cable, the state of the node device can be notified to the center side with a simple configuration.

Brief Description of the Drawings

[0023]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiment for Carrying Out the Invention

[0024] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0025] FIG. 1 is a schematic diagram showing an example of the configuration of a transmission system 1 according to an embodiment of the present invention. The transmission system 1 shown in FIG. 1 is an aspect of a system that realizes video transmission from a transmitting station such as a CATV (Cable Television) station to a subscriber's video viewing facility 8. The video viewing facility 8 is, for example, a television receiver or the like that displays a video based on the received electrical video signal.

[0026] First, an overview of the transmission system 1 will be described. The transmission system 1 of the present embodiment includes a center device 2, a monitoring server 3, an FTTH (Fiber To The Home) optical transmission line 5, a node device 10, and a coaxial cable transmission line 6. The coaxial cable transmission line 6 may include distribution facilities such as tap-offs.

[0027] The center device 2 is a device that executes video transmission installed at a transmitting station that transmits video. The transmitting station where the center device 2 is installed is, for example, a CATV (Cable Television) station or the like. The center device 2 of the present embodiment includes an optical transmitter 21 and an OLT (Optical Line Terminal) 22.

[0028] The optical transmitter 21 converts the electrical signal of the video to be transmitted into an optical video signal. The optical video signal converted from the video electrical signal by the optical transmitter 21 is transmitted to the node device 10 via the FTTH optical transmission line 5.

[0029] The OLT 22 is an external device that converts an electrical data signal acquired from the outside into an optical data signal. The optical data signal converted from the electrical data signal by the OLT 22 is transmitted to the node device 10. Also, the OLT 22 converts the optical data signal received via the FTTH optical transmission line 5 into an electrical data signal. Communication status information including information on whether the link between the OLT 22 and the node device 10 is established or the link is lost is transmitted to the monitoring server 3.

[0030] The communication method between the OLT 22 and the node device 10 in the center device 2 is, for example, the G-PON (Passive Optical Network) method or the GE-PON (Gigabit Ethernet Passive Optical Network) method. Note that the communication method is not particularly limited. As the communication method, communication methods other than the G-PON method and the GE-PON method such as the 10G-EPON method, the XG-PON method, the XGS-PON method, and the NG-PON2 method can also be used.

[0031] The monitoring server 3 is a computer that monitors the transmission system 1 and the states of the constituent devices of the transmission system 1. The monitoring server 3 of the present embodiment monitors whether an abnormality has occurred in the transmission system 1 based on the communication status between the OLT 22 and the node device 10 in the center device 2.

[0032] The FTTH optical transmission line 5 is an optical fiber network that connects the center device 2 and one or a plurality of node devices 10. The FTTH optical transmission line 5 can be branched and connected to a plurality of node devices 10 by an optical splitter (closure). The FTTH optical transmission line 5 may include a fiber for transmitting an optical video signal, a fiber for transmitting and receiving an optical data signal, etc., or the FTTH optical transmission line 5 may be made to include a fiber for transmitting an optical video signal, and a fiber for transmitting and receiving an optical data signal may be prepared separately from the FTTH optical transmission line 5. Note that the wiring of the fiber for transmitting the optical video signal and the fiber for transmitting the optical data signal may be laid physically together or separately.

[0033] The node device 10 is a node device installed on a utility pole or the like and can also be suspended from a support wire. The node device 10 converts the optical video signal received via the FTTH optical transmission line 5 into an electrical video signal. The node device 10 is connected to the FTTH optical transmission line 5 and also connected to the coaxial cable transmission line 6, and transmits the electrical video signal to the video viewing equipment 8 of the subscriber's home 7 via the coaxial cable transmission line 6.

[0034] The coaxial cable transmission line 6 is a coaxial cable that connects the node device 10 and the subscriber's video viewing equipment 8. The electrical video signal converted from the optical video signal by the node device 10 is transmitted to the subscriber's video viewing equipment 8 via the coaxial cable transmission line 6. The coaxial cable transmission line 6 of the transmission system 1 of the present embodiment can utilize the one installed when HFC (Hybrid fiber - coaxial) was operated in the past. Note that the coaxial cable transmission line 6 may be newly installed.

[0035] Next, the configuration of the node device 10 will be described. FIG. 2 is a schematic diagram showing an example of the configuration of the node device 10 of the present embodiment.

[0036] As shown in FIG. 2, the node device 10 of the present embodiment includes an optoelectronic conversion unit 31, an electrical signal amplification unit 32, a D - ONU (Optical Network Unit) 33, a power supply unit 34, and a housing 40.

[0037] The optoelectronic conversion unit 31 executes a process of converting the optical video signal received from the optical transmitter 21 via the FTTH optical transmission line 5 into an electrical video signal.

[0038] The electrical signal amplification unit 32 is an amplifier that amplifies the electrical video signal converted by the optoelectronic conversion unit 31. Even if there is a distance from the node device 10 to the video viewing equipment 8 in the subscriber's home 7, the electrical video signal can be reliably transmitted to the video viewing equipment 8 by the amplification process of the electrical signal amplification unit 32. For example, even if a conventional V-ONU installed in the subscriber's home is applied as it is, since the output level of the electrical video signal is low, if the coaxial cable transmission line 6 installed when operating HFC (Hybrid fiber-coaxial) is diverted, it is not always possible to appropriately transmit the electrical video signal to the subscriber's home. In this regard, the node device 10 of the present embodiment can arrange an electrical signal amplification unit 32 with a sufficient level, so that the electrical video signal can be amplified to a required output level by the electrical signal amplification unit 32. For example, if the output level of a conventional V-ONU installed in the subscriber's home is about 85 dBμV, the output level of the node device 10 of the present embodiment is about 105 to 110 dBμV. This enables the diversion of the coaxial cable transmission line 6 installed in the past when operating HFC (Hybrid fiber-coaxial), and prevents the degradation of the video quality transmitted to the subscriber's home 7.

[0039] The D-ONU 33 is a data communication unit that establishes a link connection with the OLT 22 via the FTTH optical transmission line 5 and performs the transmission and reception of data signals. The link connection is a so-called link-up state in which the D-ONU 33 and the OLT 22 are in a communicable state. The D-ONU 33 of the present embodiment is of the SFP (Small Form Factor Pluggable) type, and the optical fiber of the FTTH optical transmission line 5 is connected. The fiber for transmitting and receiving optical data signals may be prepared separately from the FTTH optical transmission line 5.

[0040] The power supply unit 34 supplies power to each of the optoelectronic conversion unit 31, the electrical signal amplification unit 32, and the D-ONU 33. The node device 10 of the present embodiment is a video transmission device installed on a utility pole or the like, or suspended from a support wire or the like, and the power supply unit 34 obtains power from the overhead line that transmits the power supported by the utility pole or the like.

[0041] The housing 40 houses components of the node device 10 such as the optoelectronic conversion unit 31, the electrical signal amplification unit 32, the D-ONU 33, and the power supply unit 34. Since the housing 40 is installed on outdoor utility poles, support wires, etc., it has a waterproof structure. The housing 40 of the present embodiment is installed on a utility pole or a support wire, so it can prevent water from entering from a direction below the horizontal direction, and thus has higher waterproof performance than a general V-ONU. When a V-ONU is housed in a housing for a node device as in the present invention for the purpose of waterproofing, etc., the ambient temperature may rise compared to when the V-ONU is used alone, and the usage environment may be restricted.

[0042] Next, the abnormality detection process of the transmission system 1 will be described. FIG. 3 is a flowchart showing an example of the abnormality detection process by the node device 10 of the present embodiment.

[0043] When starting up with the power supplied to the node device 10, the power supply unit 34 supplies power to each of the optoelectronic conversion unit 31, the electrical signal amplification unit 32, and the D-ONU 33 (step S11).

[0044] The optoelectronic conversion unit 31 supplied with power from the power supply unit 34 starts signal conversion processing to convert the optical video signal input via the FTTH optical transmission path 5 into an electrical video signal and output it (step S12). Also, the D-ONU 33 supplied with power from the power supply unit 34 starts link connection processing to establish a link connection with the OLT 22 on the center device 2 side via the FTTH optical transmission path 5 (step S13).

[0045] After the processing in steps S12 and S13, the process proceeds to step S14 for abnormality detection. In step S14 of the present embodiment, when the link connection between the D-ONU 33 of the node device 10 and the OLT 22 on the center device 2 side is lost, it is determined that some abnormality has occurred in the node device 10 that is performing video transmission.

[0046] If the power supply to the photoelectric conversion unit 31 becomes inappropriate due to a defect in the power supply unit 34 or an abnormal power supply to the power supply unit 34, etc., the conversion process from the optical video signal to the electrical video signal will not be performed, and the video transmission to the video viewing equipment 8 in the subscriber's home 7 will stop. In this embodiment, since the power supply unit 34 that supplies power to the D-ONU 33 also supplies power to the photoelectric conversion unit 31, if there is a defect in the power supply to the photoelectric conversion unit 31, there will also be a defect in the power supply to the D-ONU 33. When the power supply from the power supply unit 34 cannot be properly performed, the link between the D-ONU 33 and the OLT 22 cannot be maintained, and it will be in a state where the link is lost (link-down state). The state where the power supply cannot be properly performed is, for example, a state where the power supply voltage drops, changes abnormally, or the power itself is no longer supplied.

[0047] That is, it can be determined that some abnormality has occurred in the node device 10 on the center device 2 side with this state where the link is lost. The loss of the link can be determined on the center device 2 side. The OLT 22 may detect an abnormality based on the link state by itself, or the monitoring server 3 connected to the OLT 22 may detect an abnormality based on the information obtained via the OLT 22.

[0048] When an abnormality is detected in step S14, the process proceeds to step S15 where notification processing is performed (step S14; Yes). The monitoring process for the occurrence of an abnormality in step S14 continues until an abnormality is detected (step S14; No).

[0049] In step S15, after the abnormality is detected, a process for notifying the administrator or the transmission system 1 that an abnormality has occurred is executed (step S15). Various methods can be adopted for notifying the detection of an abnormality. For example, an output device such as a display device or a warning light may be connected to the OLT 22, and the administrator may be notified of the detection of an abnormality by the output device. Alternatively, the monitoring server 3 connected to the OLT 22 or a terminal registered in advance from the monitoring server 3 may be notified that an abnormality has been detected. In FIG. 4, for the sake of clarity, the time sequence of the processes is determined and described, but the processes may be performed in parallel or the order may be changed. Also, although the order of starting after power supply to the node device has been described, power supply may be performed after turning on the switch or the like of the node device.

[0050] The node device 10 of the present embodiment described above includes a photoelectric conversion unit 31 that converts an optical video signal input via the FTTH optical transmission path 5 into an electrical video signal and outputs it, a D-ONU 33 (data communication unit) that establishes a link connection with the OLT 22 (external device), and a power supply unit 34 that supplies power to both the photoelectric conversion unit 31 and the D-ONU 33.

[0051] The abnormality detection method of the present embodiment also includes a power supply step in which the power supply unit 34 supplies power to both the photoelectric conversion unit 31 that converts an optical video signal into an electrical video signal and outputs it and the D-ONU 33 (data communication unit) that establishes a link connection with the OLT 22 (external device) via the FTTH optical transmission path 5, a signal conversion step in which the photoelectric conversion unit 31 converts the optical video signal input via the FTTH optical transmission path 5 into an electrical video signal and outputs it, a connection step in which a link connection between the OLT 22 and the D-ONU 33 is established, and an abnormality detection step in which it is detected that an abnormality has occurred based on the loss of the link connection between the D-ONU 33 and the OLT 22.

[0052] In the node device 10 of the present embodiment and the abnormality detection method using the same, since the power supply unit 34 supplies power to both the optoelectronic conversion unit 31 and the D-ONU 33, if a problem occurs in the power supply unit 34, both the optoelectronic conversion unit 31 and the D-ONU 33 will stop operating, and the link connection between the OLT 22 of the center device 2 and the D-ONU 33 will be lost (link-down state). Since the link loss can be detected on the OLT 22 side of the center device 2, when a link-down occurs, the center device 2 can grasp that some abnormality has occurred in the node device 10. It is possible to detect that some abnormality has occurred in the node device 10 including the optoelectronic conversion unit 31 that converts an optical video signal into an electrical video signal with a simple configuration in which the power supply unit 34 of the node device 10 supplies power to both the optoelectronic conversion unit 31 and the D-ONU 33.

[0053] Also, in the node device 10 of the present embodiment, when the power supply from the power supply unit 34 is stopped, the link connection between the D-ONU 33 and the OLT 22 is lost. Alternatively, when the power supply voltage supplied from the power supply unit 34 decreases, the link connection between the D-ONU 33 and the OLT 22 is lost.

[0054] As a result, it is possible to detect on the center device 2 side, as an abnormality of the node device 10, the possibility that the appropriate power supply to the optoelectronic conversion unit 31 cannot be maintained due to a failure or problem in the power supply unit 34, an abnormal power supply to the power supply unit 34, etc., and the electrical video signal is not transmitted.

[0055] Further, the node device 10 of the present embodiment further includes an electrical signal amplification unit 32 that amplifies the electrical video signal output from the optoelectronic conversion unit 31, and the power supply unit 34 supplies power to the optoelectronic conversion unit 31, the electrical signal amplification unit 32, and the D-ONU 33.

[0056] As a result, it is possible to realize the power supply of the electrical signal amplification unit 32 that amplifies the signal level of the electrical video signal to an appropriate level by using the power supply unit 34 that supplies power to the optoelectronic conversion unit 31 and the D-ONU 33.

[0057] Further, the transmission system 1 of the present embodiment includes a node device 10 and an FTTH optical transmission line 5 that transmits an optical video signal input to the node device 10.

[0058] Thus, a transmission system 1 can be realized that has a simple configuration in which the power supply unit 34 of the node device 10 supplies power to both the optoelectronic conversion unit 31 and the D-ONU 33, and can detect that some abnormality has occurred in the node device 10 including the optoelectronic conversion unit 31.

[0059] Further, the transmission system 1 of the present embodiment includes a node device 10 and a coaxial cable transmission line 6 as a coaxial cable network that transmits an electrical video signal output from the node device 10. Note that the coaxial cable transmission line 6 may be a coaxial cable network including distribution facilities such as tap-offs, or may not include them.

[0060] Thus, since the existing coaxial cable transmission line 6 connecting the subscriber's home 7 and the node device 10 can be used, a video transmission service using the FTTH optical transmission line 5 can be realized at low cost without performing construction on the subscriber's home 7 or the coaxial cable transmission line 6. Note that a new coaxial cable transmission line 6 may be installed.

[0061] Above, one embodiment of the node device 10 has been described. Next, a modification having a configuration different from that of the above-described transmission system 1 and node device 10 will be described. In the following description, components and effects common or similar to those of the above embodiment may be denoted by the same reference numerals, and the description thereof may be omitted.

[0062] FIG. 4 is a schematic diagram showing an example of the configuration of a node device 10a according to the first modification. The node device 10a shown in FIG. 4 includes an optoelectronic conversion unit 31, an electrical signal amplification unit 32, a D-ONU 33, a power supply unit 34, a detection unit 35, a switch unit 36, and a housing 40.

[0063] The detection unit 35 detects an abnormality based on the signal input from the optoelectronic conversion unit 31 or the electrical signal amplification unit 32. For example, the detection unit 35 is constituted by an electrical circuit that detects the High / Low of the input signal. When the signal level of the optoelectronic conversion unit 31 falls below a predetermined lower limit value or exceeds an upper limit value, the detection unit 35 transmits an abnormal signal to a switch unit 36 described later. Or, when the signal level of the electrical signal amplification unit 32 falls below a predetermined lower limit value or exceeds an upper limit value, the detection unit 35 transmits an abnormal signal to the switch unit 36 described later. Also, it is possible to give hysteresis to the thresholds for abnormality occurrence and recovery so as to prevent chattering.

[0064] In addition, the detection unit 35 transmits an abnormal signal to the switch unit 36 based on the state of the power supply from the power supply unit 34. For example, when the detection unit 35 detects that the voltage level of the power supply unit 34 has fallen below a predetermined lower limit value or exceeded an upper limit value, the detection unit 35 transmits an abnormal signal.

[0065] The switch unit 36 controls the power supply from the power supply unit 34 to the D-ONU 33. For example, the switch unit 36 is an electrical component such as a switch or a relay arranged between the D-ONU 33 and the power supply unit 34. When the switch unit 36 receives an abnormal signal from at least one of the optoelectronic conversion unit 31 and the electrical signal amplification unit 32, for example, the switch unit 36 operates to stop or suppress the power supply from the power supply unit 34 to the D-ONU 33. Note that the detection unit 35 and the switch unit 36 may be realized by an integrated circuit or the like. Also, when an abnormality occurs, it may be configured so that it does not recover naturally, such as latching the state.

[0066] When the power supply from the power supply unit 34 stops or decreases due to the operation of the switch unit 36, the D-ONU 33 cannot maintain the link connection with the OLT 22. Similar to the node device 10 of the above-described embodiment, the loss of the link can be grasped on the center device 2 side. In the node device 10 of the first modification described above, not only the power supply unit 34 but also abnormalities in the optoelectronic conversion unit 31 and the electrical signal amplification unit 32 can be detected. In the first modification as well, since the power supply unit 34 supplies power to all of the optoelectronic conversion unit 31, the electrical signal amplification unit 32, and the D-ONU 33, if a problem occurs in the power supply unit 34, as in the above-described embodiment, a problem also occurs in the power supply to the D-ONU 33 and an abnormality can be detected.

[0067] As described above, the node device 10a of the first modification further includes a detection unit 35 that detects an abnormality in at least one of the optoelectronic conversion unit 31 and the power supply unit 34, and based on an abnormality signal indicating the abnormality from the detection unit 35, the link connection between the D-ONU 33 and the OLT 22 is lost.

[0068] Thereby, a configuration in which an abnormality other than the stop of the power supply such as the signal level of the optoelectronic conversion unit 31 or the output level of the power supply unit 34 can be grasped on the center device 2 side can be realized with a simple configuration.

[0069] The node device 10a of the first modification further includes an electrical signal amplification unit 32 that amplifies the electrical video signal output from the optoelectronic conversion unit 31. The detection unit 35 can also detect an abnormality in the electrical signal amplification unit 32 and lose the link connection between the D-ONU 33 and the OLT 22 based on an abnormality signal indicating the abnormality in the electrical signal amplification unit 32. Note that the detection unit 35 may be configured to detect only the electrical signal amplification unit 32 without detecting abnormalities in the optoelectronic conversion unit 31 and the power supply unit 34.

[0070] Thereby, the possibility of an abnormal state of the electrical signal amplification unit 32 such as the signal level of the electrical signal amplification unit 32 can be grasped on the center device 2 side as an abnormality of the node device 10.

[0071] Next, a second modified example with a configuration different from the first modified example will be described. FIG. 5 is a schematic diagram showing an example of the configuration of the node device 10b of the second modified example. In the first modified example, when an abnormality is detected, the link connection is lost by stopping the power supply to the D-ONU 33. However, in the second modified example, the link connection is lost by a method different from the first modification.

[0072] The node device 10b of the second modified example shown in FIG. 5 includes an optoelectronic conversion unit 31, an electrical signal amplification unit 32, a D-ONU 33, a power supply unit 34, a detection unit 35, and a housing 40.

[0073] The D-ONU 33 has a pin 41 that realizes a TX Disable (Transmitter Disable) function for stopping the output of the optical data signal to the OLT 22 of the center device 2. In the second modified example, an abnormal signal from the detection unit 35 is input to this pin 41 to stop the output of the optical data signal of the D-ONU 33 to the OLT 22, thereby losing the link connection.

[0074] As described above, the D-ONU 33 of the second modified example has a pin 41 as a control input unit capable of stopping the output of the optical data signal to the OLT 22. When an abnormal signal from the detection unit 35 is input to the pin 41, the output from the OLT 22 is stopped, and the link connection between the D-ONU 33 and the OLT 22 is lost. Note that the pin 41 is an example of the input unit, and something other than the pin can be adopted as the input unit.

[0075] Thereby, by using the TX Disable function of the D-ONU 33, the abnormality of the node device 10 can be grasped on the center device 2 side without stopping the power supply to the D-ONU 33.

[0076] Next, a third modified example will be described. FIG. 6 is a schematic diagram showing an example of the configuration of the node device 10c of the third modified example.

[0077] The node device 10c shown in FIG. 6 includes a photoelectric conversion unit 31, an electrical signal amplification unit 32, a D-ONU 33, a power supply unit 34, and an information processing unit 37.

[0078] The information processing unit 37 monitors the operating states of the photoelectric conversion unit 31, the electrical signal amplification unit 32, or the power supply unit 34, and detects an abnormality based on a predetermined determination condition as necessary. For example, the information processing unit 37 is a computer including any one or all of a processor such as a CPU, a main storage device such as a ROM, a memory such as a RAM, an auxiliary storage device, an IC chip that performs communication processing, and the like.

[0079] The information processing unit 37 acquires state information regarding the levels of input signals and output signals from the photoelectric conversion unit 31, and determines whether or not there is an abnormality based on a determination condition as necessary. The determination conditions are, for example, when the levels of the input signals and output signals of the photoelectric conversion unit 31 exceed a predetermined upper limit value or lower limit value, when the levels of the input signals and output signals of the photoelectric conversion unit 31 deviate significantly from the levels at the time of installation or the set levels, when irregular behavior is shown, and the like.

[0080] Similarly, the information processing unit 37 acquires state information regarding the levels of input signals and output signals from the electrical signal amplification unit 32, and determines whether or not there is an abnormality based on a determination condition as necessary. The determination conditions are, for example, when the levels of the input signals and output signals of the electrical signal amplification unit 32 exceed a predetermined upper limit value or lower limit value, when the levels of the input signals and output signals of the electrical signal amplification unit 32 deviate significantly from the levels at the time of installation or the set levels, when irregular behavior is shown, and the like.

[0081] Furthermore, the information processing unit 37 acquires state information such as the voltage of the power supplied from the power supply unit 34, and monitors the power supply state based on a determination condition as necessary. The determination conditions are, for example, when the voltage of the power supplied from the power supply unit 34 exceeds a predetermined upper limit value or lower limit value, or when the voltage shows irregular behavior different from normal, it is determined that there is an abnormality.

[0082] When the information processing unit 37 determines an abnormality based on a predetermined determination condition, it executes a notification process for transmitting the abnormality information to the center device 2. In the third modification example, the information processing unit 37 executes a process of transmitting the occurrence information of an abnormality to the OLT 22 of the center device 2 via the D-ONU 33 and the FTTH optical transmission line 5. The occurrence information of an abnormality transmitted by the information processing unit 37 can include information for identifying the node device 10c, information for identifying the subscriber's home 7 corresponding to the node device 10c, information indicating the type and level of the abnormality, and the like. In this example, it is assumed that the notification process is executed when an abnormality is determined. However, in response to a request from the center device 2 or periodically, the determination information may be notified. Further, instead of the determination information, status information regarding the level of the input signal or output signal from the optoelectronic conversion unit 31, status information regarding the level of the input signal or output signal from the electrical signal amplification unit 32, status information such as the voltage of the power supplied from the power supply unit 34, etc. may be transmitted or notified.

[0083] When the monitoring server 3 connected to the center device 2 obtains the abnormality information from the node device 10c, it executes processes such as notifying the administrator that an abnormality has occurred and updating information indicating the status of the transmission system 1. Regarding the content of the notification to the administrator and the reflection of the status, the type and detailed content of the abnormality may be notified together with the occurrence of the abnormality.

[0084] As described above, the node device 10c of the third modification example further includes an information processing unit 37 that acquires status information indicating the status of at least one of the optoelectronic conversion unit 31 and the power supply unit 34. The information processing unit 37 determines whether an abnormality has occurred based on the status information, and when an abnormality has occurred, it can execute a process of transmitting the occurrence information of the abnormality as status information to the OLT 22 via the D-ONU 33, spontaneously or in response to a request. Alternatively, the information processing unit 37 can execute a process of transmitting the status information to the OLT 22 via the D-ONU 33.

[0085] As a result, it is possible to more accurately perform the abnormality determination based on the state information acquired by the information processing unit 37, and the type and degree of the abnormality that has occurred in the optoelectronic conversion unit 31 and the power supply unit 34 can also be grasped on the center device 2 side.

[0086] The node device 10c of the third modification further includes an electrical signal amplification unit 32 that amplifies the electrical video signal output from the optoelectronic conversion unit 31. The information processing unit 37 acquires state information indicating the state of the electrical signal amplification unit 32, and when an abnormality has occurred in the electrical signal amplification unit 32, it can execute a process of spontaneously or in response to a request transmitting the abnormality occurrence information as state information to the OLT 22 via the D-ONU 33. Alternatively, the information processing unit 37 can execute a process of transmitting the state information of the electrical signal amplification unit 32 to the OLT 22 via the D-ONU 33.

[0087] As a result, the type and degree of the abnormality that has occurred in the electrical signal amplification unit 32 can also be grasped on the center device 2 side.

[0088] As described above, one embodiment and modifications of the present invention have been described. The present invention is not limited to this embodiment and modifications. Each of the above embodiment and modifications may be combined, and modifications, improvements, etc. within the scope that can achieve the object of the present invention are included in the present invention. For example, in the above embodiment and modifications, all the signals of the optoelectronic conversion unit 31, the electrical signal amplification unit 32, and the power supply unit 34 are input to the detection unit 35 and the information processing unit 37, but the number of monitoring targets can also be reduced.

[0089] For example, although the monitoring server 3 is installed outside the center device 2, it may be installed inside the center device 2.

[0090] For example, the monitoring server 3 is not always connected to the OLT 22 inside the center device 2, but is connected during regular inspections or the like, and monitors whether an abnormality has occurred in the transmission system 1 based on the communication state between the OLT 22 inside the center device 2 and the node device 10.

[0091] For example, the link connection is assumed to be in a so-called link-up state where the D-ONU 33 and the OLT 22 can communicate, but it may be a physical link or a logical link.

[0092] For example, the photoelectric conversion unit 31, the electrical signal amplification unit 32, and the power generation block for the D-ONU (data communication unit) 33 are separated, or a difference is provided in the supply voltage. When the supply voltage to the power supply unit 34 decreases or an abnormality occurs in the power supply unit 34, the D-ONU (data communication unit) 33 may be designed to be unable to maintain the link before the photoelectric conversion unit 31 and the electrical signal amplification unit 32 become unable to perform their main functions.

[0093] Although the power supply unit 34 of the node device 10 is assumed to obtain power from an overhead line that transmits the power supported by the utility pole, it may also obtain power from an uninterruptible power supply device equipped with an inverter and a charging unit, etc.

[0094] Although the node device 10 is a video transmission device installed on a utility pole or suspended from a support wire, it may be installed in other locations.

[0095] Also, for the processing of each step described with reference to the above flowchart, some steps may be omitted, steps may be appropriately added, or conditions may be combined. And the above series of processing can be executed by hardware or by software. In other words, the functional configurations shown in the above embodiments and modified examples are merely examples and are not particularly limited. That is, it is sufficient to have a function capable of executing the above series of processing as a whole, and the functional blocks used to realize this function are not particularly limited to the above embodiments and modified examples. Also, one functional block may be configured by hardware alone, by software alone, or by a combination thereof.

[0096] When a series of processes are to be executed by software, the programs constituting the software are installed in a computer or the like from a network or a recording medium. The computer may be a computer incorporated in dedicated hardware. Also, the computer may be a computer capable of executing various functions by installing various programs, for example, a general-purpose personal computer.

[0097] Further, the recording medium containing the program may be configured not only as a recording medium distributed separately from the apparatus main body for providing the program to the user, but also as a recording medium or the like provided to the user in a state pre-installed in the apparatus main body. Also, the steps of describing the program recorded on the recording medium include not only the processes performed in chronological order according to the order, but also the processes executed in parallel or individually, which do not necessarily have to be processed in chronological order.

[0098] Also, the hardware configurations shown in the above embodiments and modifications are merely examples, and are not particularly limited to this configuration. In addition to those constituted by various processing devices alone such as a single processor, a multi-processor, and a multi-core processor, those in which these various processing devices are combined with a processing circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field-Programmable Gate Array) may be adopted as those realizing a functional configuration as a processor.

Description of Reference Numerals

[0099] 1 Transmission system 5 FTTH optical transmission line (optical transmission line) 6 Coaxial cable transmission line 10, 10a, 10b, 10c Node device 31 Optoelectronic conversion unit 32 Electrical signal amplification unit 33 D-ONU (data communication unit) 34 Power supply unit 35 Detection unit 37 Information processing unit 41 Pins (input section)

Claims

1. An optoelectronic conversion unit that converts an optical video signal input via an optical transmission path into an electrical video signal and outputs it, A data communication unit that establishes a link connection with an external device, A power supply unit that supplies power to both the optoelectronic conversion unit and the data communication unit, A detection unit that detects an abnormality in at least one of the optoelectronic conversion unit and the power supply unit, and A node device in which the link connection between the data communication unit and the external device is lost based on an abnormality signal indicating an abnormality from the detection unit.

2. The node device according to claim 1, wherein the link connection between the data communication unit and the external device is lost when the supply of power from the power supply unit is stopped.

3. The node device according to claim 1, wherein the link connection between the data communication unit and the external device is lost when the power supply voltage supplied from the power supply unit decreases.

4. The data communication unit has an input unit that stops the optical output. When an abnormality signal from the detection unit is input to the input unit, the optical output from the data communication unit is stopped, and the link connection between the data communication unit and the external device is lost. The node device according to claim 1.

5. Further comprising an electrical signal amplification unit that amplifies the electrical video signal output from the optoelectronic conversion unit, The power supply unit supplies power to the optoelectronic conversion unit, the electrical signal amplification unit, and the data communication unit. The node device according to any one of claims 1 to 4.

6. Further comprising an electrical signal amplification unit that amplifies the electrical video signal output from the optoelectronic conversion unit, The detection unit detects an abnormality in the electrical signal amplification unit, The node device according to claim 1, wherein the link connection between the data communication unit and the external device is lost based on an abnormality signal indicating an abnormality in the electrical signal amplification unit.

7. Further comprising an information processing unit that acquires state information indicating the state of at least one of the optoelectronic conversion unit and the power supply unit, The information processing unit executes a process of transmitting the state information to the external device via the data communication unit. The node device according to claim 1.

8. Further comprising an electrical signal amplification unit that amplifies the electrical video signal output from the optoelectronic conversion unit, The information processing unit acquires state information indicating the state of the electrical signal amplification unit, The node device according to claim 7, wherein the information processing unit executes a process of transmitting the state information to the external device via the data communication unit.

9. The node device according to any one of claims 1 to 8, and An optical transmission line for transmitting an optical video signal input to the node device, A transmission system comprising:

10. The node device according to any one of Claims 1 to 8, A coaxial cable transmission line for transmitting an electrical video signal output from the node device, A transmission system comprising:

11. A power supply step of supplying power to both a photoelectric conversion unit that converts an optical video signal into an electrical video signal and outputs it and a data communication unit that establishes a link connection with an external device by a power supply unit, A signal conversion step of converting an optical video signal input via an optical transmission line by the photoelectric conversion unit into an electrical video signal and outputting it, A connection step of establishing a link connection between the data communication unit and the external device, An abnormality detection step of detecting that an abnormality has occurred based on the loss of the link connection between the data communication unit and the external device, A detection step of detecting an abnormality in at least one of the photoelectric conversion unit and the power supply unit, Including, An abnormality detection method in which the link connection between the data communication unit and the external device is lost based on an abnormality signal indicating the abnormality output in the detection step.

Images