JP4952395B2 - Local signal relay system, relay device, and local signal relay method - Google Patents

Description

  The present invention relates to a local signal relay technique using an optical communication line.

  Patent Document 1 discloses an automatic meter reading system that can automatically measure the amount of electricity used and the like while suppressing initial cost and running cost.

  In this automatic meter reading system, a computer in a user's home is connected to a first media converter (optical line terminal device) via a router, and a power meter (meter reading device) is connected to the media converter. On the other hand, the data collection device provided in the management center of the power supply company is connected to the second media converter (optical line termination device) via the data aggregation device. The first and second media converters are connected by an information communication network (optical communication line). The meter reading data is superimposed on the line maintenance packet signal periodically transmitted and received between the first and second media converters, and the meter reading data is selected by the data aggregating device and stored in the data collecting device. .

JP-A-2005-174107

  By the way, an optical line termination device is often installed indoors in a user's house. In particular, router-type optical line terminators tend to be installed indoors because of the network connection of user computers. On the other hand, meter-reading devices such as wattmeters are often installed outside the user's home. For this reason, in the automatic meter-reading system described in Patent Document 1, wiring between the optical line terminator and the meter-reading device becomes complicated, such as making a hole in the wall of the user's house.

The present invention has been made in view of the above circumstances, and an object of the present invention is to relay a local signal output from a meter-reading device or the like to an optical communication line network without requiring a dedicated wiring for some sections. It is to provide a technology that can do this.

  In order to solve the above problems, in the present invention, a local electrical signal output from a meter reading device or the like is converted into a local optical signal, and this local optical signal is superimposed on an arbitrary section of an optical communication line by optical wavelength division multiplexing communication. . Thereby, the local electric signal output from the meter-reading apparatus etc. is relayed to an optical line termination device.

For example, the present invention is a local signal relay system that relays a local signal using an optical fiber connected at one end to an optical communication network and drawn indoors ,
An optical line termination device connected to the other end of the optical fiber and terminating the optical communication network;
A first relay device inserted into a first location on the optical fiber;
A second portion connected to the optical line termination device via a local signal interface while being inserted into a second location located closer to the optical line termination device than the first location on the optical fiber . A relay device, and
The first relay device is
A local optical signal transmitting means for converting a local electrical signal inputted externally into a local optical signal having a wavelength different from that of the long-distance communication optical signal used in the optical communication network , and outputting the local optical signal;
A local optical signal output from said local optical signal transmitting means, said long-distance optical signal communication propagating through the optical fiber toward from the optical communication network to the optical network unit and a multiplexing means for multiplexing Have
The second relay device is
Demultiplexing means for demultiplexing the local optical signal from an optical signal propagating through the optical fiber from the optical communication network toward the optical network termination device ;
A local optical signal receiving means for restoring the local optical signal branched by the branching means to said local electrical signal, and outputs the local electrical signal to the optical line terminal through the interface of the local signal , have a,
The optical line terminator is:
The local electric signal received from the second repeater via the local signal interface is converted into the long-distance communication optical signal, and the long-distance communication is performed on the optical fiber toward the optical communication network. Outputs optical signal .

According to the present invention, a local signal output from a meter-reading device or the like can be relayed to an optical communication line network without requiring a dedicated wiring between the first relay device and the second relay device. .

  Hereinafter, an embodiment of the present invention will be described by taking as an example a case where the local signal relay system according to the present invention is applied to an automatic meter reading system.

[First embodiment]
FIG. 1 is a schematic diagram of an automatic meter reading system to which the first embodiment of the present invention is applied.

  As shown in the figure, the automatic meter reading system 1 of the present embodiment is connected to an optical communication network (optical fiber network) 90 via an optical splitter (star coupler) 8, and further via this optical communication network 90. The meter reading center device 7 is connected. The automatic meter reading system 1 includes a first relay device 2, a second relay device 3, an optical line terminal device 4, a meter reading device 5, and a local communication terminal 6.

  The meter-reading apparatus 5 is installed outdoors of the user's home 95, measures the amount of water, electricity, or gas used, and periodically outputs a measurement signal indicating the measurement result, for example.

  Similar to the meter-reading device 5, the first relay device 2 is installed outside the user's home 95 and connected to an optical fiber 91 that is one of a plurality of optical fibers branched by the optical splitter 8. It is connected to an optical fiber 92 drawn from the inside of the user's home 95 to the outside. The first relay device 2 relays a line optical signal used for PON (Passive Optical Network) between the optical fiber 91 and the optical fiber 92.

  The first relay device 2 is connected to the meter-reading device 5, converts the measurement signal output from the meter-reading device 5 into a first local light signal, and this first local light signal is sent to the second relay device 3. The first local optical signal and the optical signal propagating through the optical fiber 92 are multiplexed so as to propagate toward the optical fiber. The first repeater 2 demultiplexes the second local optical signal from the optical signal propagating through the optical fiber 92 from the second repeater 3 toward the first repeater 2, and controls the second local optical signal. It converts into a signal and outputs it to the meter-reading apparatus 5.

  FIG. 2 is a schematic diagram of the first relay device 2. As illustrated, the first relay device 2 includes a network connector 21, a home connector 22, an optical splitter 23, an optical transmitter / receiver 24, and a battery 25 that supplies power to the optical transmitter / receiver 24.

  The network side connector 21 is a connector for connecting the optical fiber 91 on the optical splitter 8 side (optical communication line network 90 side). The home-side connector 22 is a connector for connecting the optical fiber 92 on the second relay device 3 side. Here, both the connectors 21 and 22 have the light that has reached the network-side connector 21 from the optical fiber 91 incident on the optical fiber 92 through the home-side connector 22, and the light that has reached the home-side connector 22 from the optical fiber 92. Is incident on the optical fiber 91 through the network connector 21. That is, the optical fiber 91 and the optical fiber 92 are arranged so as to form an optical path that connects the end faces.

  The optical splitter 23 is disposed on the optical path connecting the optical fiber 91 and the optical fiber 92, transmits at least the line optical signals 901 and 902 used for the PON, and the first local optical signal 903 and the second local optical signal used for local communication. The optical signal 904 is reflected.

  Here, for example, light having a wavelength of 1310 nm is used for a line optical signal 901 in the downstream direction of the PON (direction from the optical communication network 90 toward the optical line termination device 4), and the upstream direction of the PON (optical line termination device) For example, light having a wavelength of 1490 nm is used for the optical signal 902 for the line in the direction from 4 to the optical communication network 90. For the first local light signal 903 and the second local light signal 904, for example, wavelength light of 1550 nm, or near infrared light and visible light of 700 nm to 1000 nm are used. The optical fibers 91 and 92 have a characteristic that the attenuation amount is the smallest in the wavelength region used for the PON. For this reason, short wavelength light such as near infrared light is greatly attenuated. However, since the local communication path length (the length of the optical fiber 92) is relatively short, short wavelength light such as near infrared light can be used for the first local optical signal 903 and the second local optical signal 904. It is.

  The optical transmission / reception unit 24 reflects the first local optical signal 903 output from the optical transmission / reception unit 24 by the optical splitter 23, enters the optical fiber 92 via the home-side connector 22, and passes from the optical fiber 92 to the home side. The second local optical signal 904 that reaches the connector 22 and is reflected by the optical splitter 23 is disposed at a position where the second optical signal 904 is incident on the own-light transmitting / receiving unit 24. As illustrated, the optical transmission / reception unit 24 includes a data transmission / reception unit 241, an optical modulation unit 242, a light emitting element 243, an optical splitter 244, a light receiving element 245, and an optical demodulation unit 246.

  The data transmitter / receiver 241 outputs the measurement signal received from the meter-reading device 5 to the light modulator 242. Further, the control signal received from the light demodulator 246 is transmitted to the meter-reading device 5.

  The optical modulation unit 242 modulates the measurement signal received from the data transmission / reception unit 241. The light emitting element 243 outputs an optical signal whose light intensity is modulated in accordance with the measurement signal modulated by the light modulator 242 as the first local optical signal 903. Note that when light having a wavelength of 700 nm to 1000 nm is used for the first local optical signal 903, an inexpensive light emitting element used for a remote controller, IrDA, or the like can be used for the light emitting element 243.

  The light receiving element 245 photoelectrically converts the received second local optical signal 904 and outputs an electrical signal. The optical demodulator 246 demodulates the control signal from the electrical signal output from the light receiving element 245 and outputs the demodulated signal to the data transmitter / receiver 241. Note that when light having a wavelength of 700 nm to 1000 nm is used for the second local optical signal 904, an inexpensive light receiving element used for a remote controller, IrDA, or the like can be used for the light receiving element 245.

  The optical splitter 244 is a half mirror that reflects part of incident light (for example, 50%) and transmits the rest. The optical splitter 244 is output from the light emitting element 243, and the first local optical signal 903 transmitted through the optical splitter 244 enters the optical splitter 23 and is output from the optical splitter 23 and reflected by the optical splitter 244. The second local optical signal 904 is disposed at a position where it enters the light receiving element 245.

  In the present embodiment, the first local optical signal 903 using the optical fiber 92 and the first local optical signal 903 and the second local optical signal 904 using the same wavelength light and having different modulation frequencies are used. Simultaneous transmission of the second local optical signal 904 is realized.

  Returning to FIG. 1, the description will be continued. The second relay device 3 is installed indoors in the user's home 95 and is connected to the optical fiber 92 from the first relay device 2. Further, it is connected to an optical fiber 93 laid indoors in the user's home 95. The second relay device 3 relays the line optical signal used for the PON between the optical fiber 92 and the optical fiber 93.

  The second relay device 3 is connected to the local communication terminal 6, converts the control signal output from the local communication terminal 6 into a second local optical signal, and the second local optical signal is converted into the first relay device. The second local optical signal and the optical signal propagating through the optical fiber 92 are combined so as to propagate toward the second line. Further, the first local optical signal is demultiplexed from the optical signal propagating through the optical fiber 92 from the first repeater 2 to the second repeater 3, and the first local optical signal is converted into a measurement signal to perform local communication. Output to the terminal 6.

  FIG. 3 is a schematic diagram of the second relay device 3. As illustrated, the second relay device 3 includes a network side connector 31, a home side connector 32, an optical splitter 33, and an optical transmission / reception unit 34.

  The network-side connector 31 is a connector for connecting the optical fiber 92 on the first relay device 2 side. The home-side connector 32 is a connector for connecting the optical fiber 93 on the optical line termination device 4 side. Here, in both connectors 31 and 32, the light that has reached the network-side connector 31 from the optical fiber 92 is incident on the optical fiber 93 via the home-side connector 32 and the light that has reached the home-side connector 32 from the optical fiber 93. Is incident on the optical fiber 92 via the network connector 31. That is, the optical fiber 92 and the optical fiber 93 are arranged so as to form an optical path that connects the end faces.

  Note that the optical fibers 92 and 93 are shorter than the optical fiber 91 because they are installed indoors in the user's home 95. For this reason, for example, plastic fibers can be used as the optical fibers 92 and 93.

  The optical splitter 33 is disposed on an optical path connecting the optical fiber 92 and the optical fiber 93, transmits at least the line optical signals 901 and 902 used for the PON, and the first local optical signal 903 and the second local optical signal used for local communication. The optical signal 904 is reflected.

  The optical transmitter / receiver 34 reaches the network connector 31 from the optical fiber 92, the first local optical signal 903 reflected by the optical splitter 33 is incident on the own optical transmitter / receiver 34, and the first optical transmitter / receiver 34 outputs the first local optical signal 903. The two local optical signals 904 are reflected by the optical splitter 33 and arranged at a position where they enter the optical fiber 92 via the network side connector 31. As illustrated, the optical transmission / reception unit 34 includes a data transmission / reception unit 341, an optical modulation unit 342, a light emitting element 343, an optical splitter 344, a light receiving element 345, and an optical demodulation unit 346.

  The data transmitter / receiver 341 outputs the control signal received from the local communication terminal 6 to the optical modulator 342. In addition, the measurement signal received from the optical demodulation unit 346 is transmitted to the local communication terminal 6.

  The optical modulation unit 342 modulates the control signal received from the data transmission / reception unit 341. The light emitting element 343 outputs an optical signal whose light intensity is modulated in accordance with the control signal modulated by the light modulator 342 as the second local optical signal 904.

  The light receiving element 345 photoelectrically converts the received first local optical signal 903 and outputs an electrical signal. The optical demodulator 346 demodulates the measurement signal from the electrical signal output from the light receiving element 345 and outputs the demodulated signal to the data transmitter / receiver 341.

  The optical splitter 344 is a half mirror that reflects a part (eg, 50%) of incident light and transmits the rest. The optical splitter 344 outputs the first local optical signal 903 output from the optical splitter 33 and reflected by the optical splitter 344, enters the light receiving element 345, is output from the light emitting element 343, and passes through the optical splitter 344. The two local optical signals 904 are arranged at positions where they enter the optical splitter 33.

  Returning to FIG. 1, the description will be continued.

  The optical line termination device 4 terminates the optical communication line network 90 and connects the LAN 94 built in the user's home 95 via the optical fibers 92 and 93, the first relay device 2, and the second relay device 3. To the optical communication network 90. In addition, the measurement data received from the local communication terminal 6 is transmitted to the meter reading center apparatus 7, and the control data received from the meter reading center apparatus 7 is transmitted to the local communication terminal 6.

  The local communication terminal 6 transfers the measurement data represented by the measurement signal output from the second relay device 3 to the optical line termination device 4. Thereby, the measured value (measurement data) of the usage amount of water, gas, electricity and the like measured by the meter-reading device 5 is transmitted to the meter-reading center device 7 via the optical line terminal device 4. Further, the local communication terminal 6 transfers a control signal indicating control data output from the optical line terminating device 4 to the second relay device 3. Thereby, the control data output from the meter reading center device 7 is transmitted to the meter reading device 5.

  FIG. 4 is a schematic diagram of the optical line termination device 4. As shown in the figure, the optical network unit 4 includes a PON optical transceiver 41, a LAN interface (IF) unit 42, a local signal interface (IF) unit 43, and a PON communication control unit 44.

  The PON optical transmission / reception unit 41 is an interface for connecting to the optical communication network 90 via the optical fibers 92 and 93, the first relay device 2, and the second relay device 3. The PON optical transmission / reception unit 41 performs light intensity modulation on light of a predetermined wavelength (for example, 1490 nm) according to the data received from the PON communication control unit 44, and generates an optical signal 902 for the upstream line of the PON. Output to. In addition, the optical fiber 93 receives a PON downlink optical signal 901 having a predetermined wavelength (eg, 1310 nm), and demodulates the received signal into data. Then, the demodulated data is passed to the PON communication control unit 44.

  The LAN interface unit 42 is an interface for connecting to the LAN 94. The LAN interface unit 42 stores the communication data received from the PON communication control unit 44 in a LAN frame and transmits it to the LAN 94. Further, it receives a LAN frame from the LAN 94, extracts communication data from the LAN frame, and outputs it to the PON communication control unit 44.

  The local signal interface unit 43 is an interface for connecting the local communication terminal 6. The local signal interface unit 43 transmits the control data received from the PON communication control unit 44 to the local communication terminal 6. In addition, the measurement data is received from the local communication terminal 6 and transferred to the PON communication control unit 44.

  The PON communication control unit 44 performs transmission / reception timing control peculiar to the PON, and performs relay processing between the PON optical transmission / reception unit 41 and the LAN interface unit 42 and between the PON optical transmission / reception unit 41 and the local signal interface unit 43. I do.

  As illustrated, the PON communication control unit 44 includes a packet filter 4401, a PON optical transmission / reception unit queue 4402, a LAN interface unit queue 4403, and a local signal interface unit queue 4404.

  The PON optical transmission / reception unit queue 4402 is a queue for storing data received from the PON optical transmission / reception unit 41. The LAN interface unit queue 4403 is a queue for storing communication data received from the LAN interface unit 42. The local signal interface unit queue 4404 is a queue for storing measurement data received from the local signal interface unit 43.

  The packet filter 4401 examines the header information of the data stored in the PON optical transmission / reception unit queue 4402. If this data is communication data addressed to the LAN 94, the data is relayed to the LAN interface unit 42. When the control data is addressed to the local communication terminal 6, the data is relayed to the local signal interface unit 43. Further, the packet filter 4401 relays the communication data stored in the LAN interface unit queue 4403 and the measurement data stored in the local signal interface unit queue 4404 to the PON optical transmission / reception unit 41. It should be noted that when data is stored in both the LAN interface unit queue 4403 and the local signal interface unit queue 4404, which data is preferentially relayed to the PON optical transmission / reception unit 41 is set in advance. You may make it leave.

  Next, the flow of signals in the automatic meter reading system 1 having the above configuration will be described.

  FIG. 5 is a diagram for explaining the flow of signals in the automatic meter reading system 1.

  The optical signal 901 for the downstream line of the PON sent from the optical communication line network 90 via the optical splitter 8 is sent to the optical line terminator 4 via the first repeater 2 and the second repeater 3. To reach. The optical line terminator 4 demodulates this line optical signal 901 into an electrical signal and extracts data. If this data indicates communication data 942 addressed to the LAN 94, the data is transmitted to the LAN 94. If control data 943 addressed to the local communication terminal 6 is indicated, the data is transmitted to the local communication terminal 6. The local communication terminal 6 transmits a control signal 944 indicating the control data 943 to the second relay device 3. The second relay device 3 converts the control signal 944 received from the local communication terminal 6 into a second local optical signal 904, and the second local optical signal 904 is directed from the second relay device 3 to the first relay device 2. To the optical signal propagating through the optical fiber 92. Then, the first repeater 2 demultiplexes the second local optical signal 904 from the optical signal propagating through the optical fiber 92 from the second repeater 3 toward the first repeater 2, and demodulates it to the control signal 945. And transmitted to the meter-reading device 5.

  Further, the optical line termination device 4 converts the communication data 941 sent from the LAN 94 into a line optical signal 902 in the upstream direction of the PON and outputs it to the optical fiber 93. The line optical signal 902 is sent to the optical communication line network 90 via the second repeater 3, the first repeater 2, and the optical splitter 8.

  Further, the first relay device 2 converts the measurement signal 946 output from the meter-reading device 5 into a first local light signal 903, and the first local light signal 903 is converted from the first relay device 2 to the second relay device 3. To the optical signal propagating through the optical fiber 92. Then, the second repeater 3 demultiplexes the first local optical signal 903 from the optical signal propagating through the optical fiber 92 from the first repeater 2 toward the second repeater 3, and demodulates it to the measurement signal 947. To the local communication terminal 6. The local communication terminal 6 transmits measurement data 948 indicated by the measurement signal 947 to the optical line terminating device 4. The optical line terminator 4 converts this measurement data 948 into an optical signal 902 for the upstream line of PON and outputs it to the optical fiber 93. The line optical signal 902 is sent to the optical communication line network 90 via the second repeater 3, the first repeater 2, and the optical splitter 8.

  The first embodiment of the present invention has been described above.

  In the present embodiment, the measurement signal output from the meter-reading device 5 is converted into a first local optical signal, and this first local optical signal is directed from the first relay device 2 to the second relay device 3 by optical wavelength multiplexing communication. Combines with optical signal. The second repeater 3 demultiplexes the first local optical signal, demodulates it into a measurement signal, and transmits it to the optical line terminating device 4 via the local communication terminal 6. Therefore, the measurement signal of the meter-reading device 5 is sent to the meter-reading center device 7 without requiring a dedicated wiring (wiring for automatic meter-reading service) separate from the optical fiber 92 between the first relay device 2 and the second relay device 3. Can be sent to.

  In the present embodiment, the control signal representing the control data sent from the meter reading center device 7 to the local communication terminal 6 is converted into a second local optical signal, and the second local optical signal is converted by optical wavelength multiplexing communication. The optical signal from the second repeater 3 to the first repeater 2 is multiplexed. Then, in the first relay device 2, the second local optical signal is demultiplexed, demodulated into a control signal, and transmitted to the meter-reading device 5. Therefore, the control data of the meter-reading center device 7 is transferred to the meter-reading device 5 without requiring a dedicated wiring (automatic meter-reading service wiring) separate from the optical fiber 92 between the first relay device 2 and the second relay device 3. Can be sent to.

  For this reason, according to the present embodiment, for example, when the first relay device 2 is arranged outdoors in the user's home 95 and the second relay device 3 is in the user's home 95, the optical fiber 92 is Since it is not necessary to provide another dedicated wiring, an automatic meter reading service can be realized without performing a complicated operation such as making a hole in the wall of the user's home 95. For example, even if a meter-reading device for each lifeline, such as electric power, water, gas, etc., is individually provided outside the user's home 95, one optical fiber is laid between the indoor and the outdoor of the user's home 95 Therefore, the connection wiring can be prevented from becoming complicated.

  Further, in the present embodiment, the local communication terminal 6 is connected to the optical line terminating device 4 using an interface (local signal interface unit 43) provided separately from an interface (LAN interface unit 42) for connecting the LAN 94. Connected. By doing so, communication can be performed between the meter-reading device 5 and the meter-reading center device 7 even when a failure occurs in the LAN 94 that the user will construct. Therefore, an automatic meter reading service that can be easily maintained can be realized.

[Second Embodiment]
FIG. 6 is a schematic view of an automatic meter reading system to which the second embodiment of the present invention is applied.

  As shown in the figure, the automatic meter reading system 1A of the present embodiment is different from the automatic meter reading system 1 of the first embodiment shown in FIG. 1 in that the second relay device 3, the optical line terminating device 4, and the local communication. Instead of the terminal 6, an optical line termination device 4A in which these devices are integrated is provided.

  FIG. 7 is a schematic diagram of the optical line termination device 4A. Here, the same name and the same code | symbol are attached | subjected to what has the same function as the structure of 1st embodiment.

  As shown in the figure, in the optical line termination device 4A of the present embodiment, the home side connector 32 is omitted from the second relay device 3 (see FIG. 3) according to the first embodiment, and this omitted home side. By disposing the PON optical transmission / reception unit 41 of the optical line termination device 4 (see FIG. 4) according to the first embodiment at the position of the connector 32, the second relay device 3 according to the first embodiment and The optical line terminator 4 is integrated. Further, instead of the local communication terminal 6 according to the first embodiment, a local communication unit 61 is arranged in the optical line termination device 4A, and the measurement signal output from the optical transmission / reception unit 34 by the local communication unit 61 is provided. Is transferred to the PON communication control unit 44, and a control signal indicating the control data output from the PON communication control unit 44 is transferred to the optical transmission / reception unit 34.

  The second embodiment of the present invention has been described above.

  The present embodiment has the following effects in addition to the effects of the first embodiment.

  That is, according to the present embodiment, the optical line termination device 4A in which the second relay device 3, the optical line termination device 4, and the local communication terminal 6 according to the first embodiment are integrated is used. For this reason, the complexity of the connection wiring among the 2nd relay apparatus 3, the optical line terminal device 4, and the local communication terminal 6 can be reduced. Note that such an optical line termination device 4 </ b> A tends to be installed indoors in the user's home 95. Therefore, it is very useful not to require a dedicated wiring different from the optical fiber 92 in order to connect to the first relay device 2 disposed outside the user's home 95.

[Third embodiment]
The difference between the present embodiment and the first and second embodiments is that the first relay device 2A is used instead of the first relay device 2.

  FIG. 8 is a schematic diagram of the first relay device 2A. Here, the same name and code | symbol are attached | subjected to what has the same function as the 1st relay apparatus 2 shown in FIG.

  As shown in the figure, the first relay device 2A is different from the first relay device 2 shown in FIG. 2 in that an optical transmission / reception unit 24A is provided in place of the optical transmission / reception unit 24, and a new photoelectric conversion unit 26, power storage The control unit 27 is provided.

  The optical transmission / reception unit 24A reflects the first local optical signal 903 output from the own optical transmission / reception unit 24A by the optical splitter 23, enters the optical fiber 92 via the home-side connector 22, and passes from the optical fiber 92 to the home side. The second local optical signal 904 that reaches the connector 22 and is reflected by the optical splitter 23 is disposed at a position where the second local optical signal 904 is incident on the own-light transmitting / receiving unit 24A. As illustrated, the optical transmission / reception unit 24A includes a data transmission / reception unit 241, a light receiving element 245, an optical demodulation unit 246, an electronic shutter control unit 247, an electronic shutter 248, and an optical system 249.

  The data transmission / reception unit 241 outputs the measurement signal received from the meter-reading device 5 to the electronic shutter control unit 247. Further, the control signal received from the light demodulator 246 is transmitted to the meter-reading device 5.

  The optical system 249 divides and outputs incident light in three directions. For the optical system 249, for example, a corner cube prism can be used. The corner cube prism transmits a part of the input light. The other part is reflected at right angles to the light traveling direction. Then, the remaining light is reflected at a right angle with respect to the traveling direction of the light, and further reflected at a right angle, thereby being folded back in the incident direction at a position shifted from the optical path of the incident light. In this optical system 249, a part of the second local optical signal 904 incident from the optical splitter 23 is incident on the light receiving element 245, the other part is incident on the photoelectric conversion unit 26, and the remaining light is transmitted to the first light signal 245. The second local optical signal 904 is folded in the incident direction of the second local optical signal 904 at a position shifted from the optical path, and is incident on the optical splitter 23.

  The light receiving element 245 photoelectrically converts the second local optical signal 904 received via the optical system 249 and outputs an electrical signal. The optical demodulator 246 demodulates the control signal from the electrical signal output from the light receiving element 245 and outputs the demodulated signal to the data transmitter / receiver 241.

  The electronic shutter 248 is disposed on the optical path of the second local optical signal 904 that is folded back in the incident direction by the optical system 249. For example, liquid crystal is used for the electronic shutter 248.

  The electronic shutter control unit 247 controls the electronic shutter 248 according to the control signal received from the data transmission / reception unit 341. Accordingly, the second local optical signal 904 turned back in the incident direction by the optical system 249 is subjected to optical intensity modulation to generate a first local optical signal 903 indicating a control signal, and this first local optical signal 903 is generated. Is incident on the optical splitter 23.

  In the present embodiment, the modulation frequency of the first local optical signal 903 is made higher than the modulation frequency of the second local optical signal 904, and the light intensity of the first local optical signal 903 in the low state is set to the second local light. The first local optical signal 903 can be generated from the second local optical signal 904 by making it lower than the light intensity of the signal 904 in the low state.

  9A schematically shows the light intensity waveform of the second local optical signal 904, FIG. 9B schematically shows the control waveform of the transmittance of the electronic shutter 248, and FIG. FIG. 9C is a diagram schematically illustrating the light intensity waveform of the first local optical signal 903. Here, reference numeral 905 denotes a modulation period of the second local optical signal 904, and reference numeral 906 denotes a pulse detection threshold used when demodulating the second local optical signal 904. Reference numeral 907 denotes a modulation period of the first local optical signal 903, and reference numeral 908 denotes a pulse detection threshold used when demodulating the first local optical signal 903.

  As illustrated, in the present embodiment, the modulation frequency of the first local optical signal 903 is higher than the modulation frequency of the second local optical signal 904, and the light intensity in the low state of the first local optical signal 903 is the first. The transmittance of the electronic shutter 248 is controlled so as to be lower than the light intensity in the low state of the two local light signal 904. In this way, the control waveform of the transmittance of the electronic shutter 248 shown in FIG. 9B is extracted from the first local optical signal 903 by using the pulse detection threshold 908 set lower than the pulse detection threshold 906. The control data can be demodulated from the extracted waveform.

  Returning to FIG. The photoelectric conversion unit 26 photoelectrically converts the second local optical signal 904 received via the optical system 249 and outputs an electrical signal. The power storage control unit 27 stores the battery 25 using the electrical signal output from the photoelectric conversion unit 26 as a power source.

  The third embodiment of the present invention has been described above.

  The present embodiment has the following effects in addition to the effects of the first and second embodiments.

  That is, in the present embodiment, the battery 25 of the first relay device 2A is stored using a part of the second local optical signal 904 as a power source. For this reason, it is not necessary to connect the first relay device 2A to an outlet such as a household power source. Moreover, it can install in the location which sunlight does not reach compared with the system using a solar cell.

  In the present embodiment, a part of the second local optical signal 904 is subjected to optical intensity modulation to generate the first local optical signal 903. Therefore, it is not necessary to provide a light source for generating the first local optical signal 903 in the first repeater 2A. Therefore, the power consumption of the first relay device 2A can be reduced, the battery need not be replaced for a long time, and the maintenance cost can be reduced.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the gist. For example, each configuration of the first repeater 2, the second repeater 3, and the optical line terminator 4 is implemented by an integrated logic IC such as ASIC (Application Specific Integrated Circuit) or FPGA (Field Programmable Gate Array). It may be executed by a computer such as a DSP (Digital Signal Processor).

  In each of the above embodiments, the first local optical signal using the optical fiber 92 is obtained by using the same wavelength light for the first local optical signal 903 and the second local optical signal 904 and making the modulation frequencies different from each other. Simultaneous transmission of 903 and the second local optical signal 904 is realized. However, the present invention is not limited to this. Simultaneous transmission of the first local optical signal 903 and the second local optical signal 904 using the optical fiber 92 may be realized by using different wavelength lights for the first local optical signal 903 and the second local optical signal 904. . Alternatively, although not simultaneous transmission, transmission of the first local optical signal 903 and the second local optical signal 904 using the optical fiber 92 may be realized by half-duplex communication.

  In each of the above-described embodiments, measurement data and control data are transmitted and received between the meter-reading center device 7 and the optical line terminal device 4 using normal packet signals. However, the present invention is not limited to this. Measurement data and control data may be transmitted and received using a packet signal for line maintenance. However, in this case, it is necessary to link the meter-reading center device 7 and the optical line terminal device 4 with the PON station side device. For this reason, restrictions arise in the automatic meter reading service.

  In the above embodiment, the case where PON is used as the optical line termination device has been described as an example. However, the present invention is not limited to this. The optical line termination device may be a media converter.

  In the above-described embodiment, the first relay device 2 may have the function (configuration) of the second relay device 3. Similarly, the second relay device 3 may have the function (configuration) of the first relay device 2.

  In each of the above embodiments, the case where the local signal relay system of the present invention is applied to an automatic meter reading system has been described as an example. However, the present invention is not limited to this. The present invention can be applied to various systems such as a remote control system.

FIG. 1 is a schematic diagram of an automatic meter reading system to which the first embodiment of the present invention is applied. FIG. 2 is a schematic diagram of the first relay device 2. FIG. 3 is a schematic diagram of the second relay device 3. FIG. 4 is a schematic diagram of the optical line termination device 4. FIG. 5 is a diagram for explaining the flow of signals in the automatic meter reading system 1. FIG. 6 is a schematic view of an automatic meter reading system to which the second embodiment of the present invention is applied. FIG. 7 is a schematic diagram of the optical line termination device 4A. FIG. 8 is a schematic diagram of the first relay device 2A. 9A schematically shows the light intensity waveform of the second local optical signal 904, FIG. 9B schematically shows the control waveform of the transmittance of the electronic shutter 248, and FIG. FIG. 9C is a diagram schematically illustrating the light intensity waveform of the first local optical signal 903.

Explanation of symbols

  1: automatic meter reading system, 2: first relay device, 3: second relay device, 4: optical line termination device, 5: meter reading device, 6: local communication terminal, 7: meter reading center device, 8: optical splitter, 21 : Network side connector, 22: Home side connector, 23: Optical splitter, 24: Optical transmission / reception unit, 25: Battery, 31: Network side connector, 32: Home side connector, 33: Optical splitter, 34: Optical transmission / reception unit, 41 : PON optical transmission / reception unit, 42: LAN interface unit, 43: local signal interface unit, 44: PON communication control unit, 90: optical communication network, 91: optical fiber, 92: optical fiber, 93: optical fiber, 94: LAN: 95: user's house, 241: data transmission / reception unit, 242: light modulation unit, 243: light emitting element, 244: optical splitter, 245: light receiving element, 246: light demodulation unit, 3 1: Data transmission / reception unit, 342: Optical modulation unit, 343: Light emitting element, 344: Optical splitter, 345: Light receiving element, 346: Optical demodulation unit, 4401: Packet filter, 4402: PON optical transmission / reception unit queue, 4403: LAN Queue for interface section, 4404: Queue for local signal interface

Claims (8)

A local signal relay system that relays a local signal using an optical fiber that is connected to an optical communication line network and drawn indoors ;
An optical line termination device connected to the other end of the optical fiber and terminating the optical communication network;
A first relay device inserted into a first location on the optical fiber;
A second portion connected to the optical line termination device via a local signal interface while being inserted into a second location located closer to the optical line termination device than the first location on the optical fiber . A relay device, and
The first relay device is
A local optical signal transmitting means for converting a local electrical signal inputted externally into a local optical signal having a wavelength different from that of the long-distance communication optical signal used in the optical communication network , and outputting the local optical signal;
A local optical signal output from said local optical signal transmitting means, said long-distance optical signal communication propagating through the optical fiber toward from the optical communication network to the optical network unit and a multiplexing means for multiplexing Have
The second relay device is
A demultiplexing means for demultiplexing said local optical signal from the optical signal propagated through the optical fiber toward the front Symbol optical communication network to the optical network unit,
A local optical signal receiving means for restoring the local optical signal branched by the branching means to said local electrical signal, and outputs the local electrical signal to the optical line terminal through the interface of the local signal , have a,
The optical line terminator is:
The local electric signal received from the second repeater via the local signal interface is converted into the long-distance communication optical signal, and the long-distance communication is performed on the optical fiber toward the optical communication network. A local signal relay system that outputs an optical signal for use . The local signal relay system according to claim 1 ,
The second relay device is
A local signal relay system, wherein the local signal relay system is integrated with the optical line terminator. The local signal relay system according to claim 1 or 2 ,
The second relay device is
A modulated light transmitting means for transmitting the modulated light of wavelength different from that of the long distance optical signal communication,
Modulated optical multiplexing that combines the modulated light output from the modulated light transmission means with the optical signal for long-distance communication propagating through the optical fiber from the optical line termination device toward the optical communication network. And further comprising means
The first relay device is
Further comprising modulated optical demultiplexing means for demultiplexing the modulated light from an optical signal propagating through the optical fiber from the optical line termination device toward the optical communication network ;
The local optical signal transmission means includes
According external input said local electrical signal, said generating said local optical signal to optical intensity modulating said modulated light demultiplexed by the modulated optical demultiplexing means, characterized in that output to the combining means A local signal relay system. The local signal relay system according to claim 3 ,
The first relay device is
Local signal relay system further comprising a storage means for storing electric part of the modulated light branched by the modulated optical demultiplexing means to photoelectric conversion. A local signal relay system according to any one of claims 1 to 4 ,
The local electrical signal is
It is meter reading data output from meter reading devices such as water, electricity, gas,
The optical line terminator is:
The meter reading data received from the second relay device through the local signal interface is converted into the long-distance communication optical signal, and the long-distance communication optical signal is connected to the optical communication network. A local signal relay system , wherein the signal is transmitted to the device of the meter reading center via the optical fiber . The 1st relay apparatus used with the local signal relay system as described in any one of Claims 1 thru | or 5 . The 2nd relay apparatus used with the local signal relay system as described in any one of Claims 1 thru | or 5 . A local signal relay method for relaying a local signal using an optical fiber connected at one end to an optical communication network and drawn indoors ,
An optical line terminator for terminating the optical communication line network is installed at the other end of the optical fiber, a first repeater is installed at a first location on the optical fiber, and A second relay device connected to the optical line terminator via a local signal interface at a second location located on the optical line terminator side of the first location of
The first relay device is
A local electrical signal externally input, converts the local optical signal having a wavelength different from the long-distance communication optical signal used in the optical communication network, the local optical signal, the optical line termination from the optical communication network the long distance communication optical signal and multiplexes that propagates through the optical fiber toward the device,
The second relay device is
The demultiplexes the local optical signal from the optical signal propagated through the optical fiber toward the optical network unit from the optical communication network, to restore the local optical signal to said local electrical signal, the local Outputting the local electrical signal to the optical line termination device via a signal interface ;
The optical line terminator is:
The local electrical signal is received from the second repeater via the local signal interface, converted into the long-distance communication optical signal, and the optical fiber is connected to the optical fiber toward the optical communication network. A local signal relay method characterized by outputting an optical signal for distance communication .

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