JP4347001B2 - CATV monitoring system and CATV monitoring method - Google Patents

Description

  The present invention relates to a CATV monitoring system and a CATV monitoring method that enable remote monitoring control of a hub device in an HFC (Hybrid Fiber Coaxial), which is a CATV transmission method having both optical transmission and coaxial transmission.

A conventional HFC system will be described with reference to FIG. First, the downstream direction in which a signal flows from the center 501 toward the subscriber will be described.
A CATV optical signal obtained by inputting a CATV signal to a downstream optical transmitter installed in the center 501 and subjected to electro-optical conversion is received by a downstream optical receiver in the node device 502 installed in a field or the like through an optical fiber. . When a redundant configuration is achieved by using a plurality of optical fiber transmission lines and center optical transmitters, a plurality of optical receivers are installed, and the outputs of the respective optical receivers are input to the switch and switched.

  Here, the photoelectrically converted CATV signal passes through the subsequent coaxial transmission line 503 (coaxial cable, relay amplification device, branching device, protector, etc.) and STB (set top box) of each subscriber home 504. ) And send video / audio signals to the TV. The data is received by a CM (cable modem) and sent to a PC (personal computer) or the like.

  Next, the upward direction in which a signal flows from the subscriber's home toward the center will be described. The STB viewing control signal, CM data signal, etc. (referred to as upstream CATV signal) of the subscriber's home 504 pass through the coaxial transmission line 503 (coaxial cable, protector, branching device, relay amplification device, etc.), and the node device 502 is reached. The upstream CATV signal is converted into a CATV optical signal by the optical transmitter in the node device 502, transmitted through the upstream optical fiber, and received by the upstream optical receiver in the center 501. When a redundant configuration is achieved by using a plurality of optical transmitters in an optical fiber transmission line or a node device, a plurality of optical receivers are installed, and the outputs of the respective optical receivers are input to the switch and switched.

  As described above, in the conventional conventional HFC system, the downstream signal is photoelectrically converted by the node device and the upstream signal is electro-optically converted. It can easily be done with a signal.

  With respect to the conventional HFC system, various types of HFC systems are currently being studied, in which an optical fiber is laid to a location closer to the subscriber and the transmission capacity when using a cable modem is largely increased. A conventional example of such a conventional HFC system is shown in FIG.

  In FIG. 3 showing a conventional example, a hub device 203 is installed between the center 201 and the node device 202, and a coaxial transmission line 205 is laid from each node device 202 to the subscriber 204. As a result, the number of target households of each node device is set to several tens to several hundreds. The distance between the center and the hub device is also relatively long, and the distance between the hub device and each node device is relatively short.

  Next, the contents of the conventional example shown in FIG. 4 will be described in detail. The CATV optical signal is transmitted from the downstream optical transmitter in the center 301 to the downstream optical receiver in the hub device 303. When the redundant configuration is adopted, switching is performed by the switch, and again by the optical transmitter in the hub device 303. Electro-optical conversion is performed, N light is branched by a nearby closure 304 or the like, and received by optical receivers in N node devices 302.

  The upstream CATV optical signal is transmitted from the upstream optical transmitter in each node device 302 to the N-wave WDM filter in the hub device 303, and is wavelength multiplexed. The upstream CATV optical signal multiplexed by the hub device 303 or the nearby closure 304 is transmitted to the center 301, separated into each wavelength by the N-wave WDM filter, and received by each optical receiver. When the redundant configuration is adopted, it is selected by the switch and the upstream CATV signal reaches the center.

  In Patent Document 1 whose technical content is similar to that of the present invention, a monitor signal corresponding to a broadcast signal actually received on the downstream side is transmitted from the downstream side to the upstream side, and the monitor signal is monitored on the upstream side. I have to. As a result, sufficient maintenance management can be performed by directly diagnosing actual received images.

  Patent Document 2 is an invention related to a light reception level monitoring system for HFC transmission that combines and transmits a plurality of optical signals, and generates a reference signal to be inserted into an electrical signal before conversion of the transmitted optical signal. After the optical signals transmitted and received in a batch are converted into electrical signals, the reference signal is extracted from the branch signal of the electrical signal, and the light reception level of each optical signal is monitored based on the level of the extracted reference signal. It is said.

  In Patent Document 3, optical signals for conventional services such as video, audio, and data and optical signals for Gigaisa service are wavelength division multiplexed. In Patent Document 4, a computer includes a plurality of optical transmitter modules and optical receiver modules. In other words, each technique for polling other cable television element modules in order and determining their operation is disclosed.

Utility Model Registration No. 3012995 JP 2001-144686 A JP 2003-009112 A Japanese Translation of National Publication No. 07-500705

Problems in the prior art to be solved by the present invention are as follows.
In the conventional system example shown in FIGS. 3 and 4, the upstream CATV signal is not handled as an electrical signal in the hub apparatus. For this reason, there is a problem that the hub device cannot be monitored.
In the conventional example of FIG. 5, a monitoring controller 407 is mounted inside for the purpose of remotely monitoring and controlling the hub device 403 from the center 401. In Conventional Example 4, the downlink monitoring control signal can be detected by the monitoring controller 407 from the switch output signal. However, a signal is sent to the optical transmitter 408 to send an upstream monitoring control signal, and the upstream monitoring control optical signal from the optical transmitter 408 is sent to the center 401 through a separate optical fiber. For this monitoring control, an optical transmitter 408 must be mounted and an optical fiber transmission line must be prepared. Therefore, there is a problem that the configuration becomes complicated.

The present invention relates to a center, a hub device existing between the center and the node device, a closure having an N branching device for N-branching an optical signal of the hub device and connecting between the N node devices, In a CATV monitoring system comprising a node device connected to a communication device of a subscriber's home, a monitoring controller is mounted inside the hub device, and the hub device performs remote monitoring control from the center, and the hub device Has an optical transmitter and an optical branching device, and the optical transmitter converts the downstream CATV signal and the upstream monitoring control signal into an electro-optical signal. It is characterized in that a part of the output is sent to the center by branching so as to include .

The present invention is a communication device subscribers home, STB (Set Top Box), TV, CM (Cable Modem), is characterized in that included either a PC (personal computer), of.

In the present invention, the hub device includes an optical coupler, and the optical coupler is coupled with an upstream CATV optical signal or is input to an unused wavelength port of an N-wave WDM filter and is partly output to the center. It is characterized by sending .

The present invention is characterized in that the upstream monitoring control signal has a wavelength other than the upstream CATV optical signal wavelength when combined with the upstream CATV optical signal by the optical coupler.

The CATV monitoring method of the present invention is a CATV monitoring method in which a communication device at a subscriber's home, a node device, and a hub device are connected and a hub device and a center are connected to each other, and a monitoring controller is provided inside the hub device. The optical transmitter in the hub device electro-optically converts the downstream CATV signal and the upstream monitoring control signal, and the optical branching device in the hub device includes an upstream monitoring control signal with a part of the output of the optical transmitter In this way, the information is branched and sent to the center, and the center performs remote monitoring control for the presence or absence of communication abnormality based on the electro-optic converted signal .

The CATV monitoring method of the present invention is characterized in that it is combined with an upstream CATV optical signal or inputted to an unused wavelength port of an N-wave WDM filter and a part of the output is sent to the center.

In the CATV monitoring system and CATV monitoring method of the present invention, it is possible to perform remote monitoring control of the hub device from the center without specially preparing an optical transmitter for upstream monitoring control signals and an optical fiber transmission line in the hub device. The effect that it becomes.
Furthermore, by returning a part of the downstream CATV optical signal to the center, it becomes possible to monitor the actual optical level obtained by branching the level change amount of the downstream CATV optical signal.

Embodiments of a CATV monitoring system and a CATV monitoring method according to the present invention will be described in detail with reference to the accompanying drawings. Referring to FIG. 1, an embodiment of the CATV monitoring system and CATV monitoring method of the present invention is shown.
According to the CATV monitoring system and CATV monitoring method of the present invention, monitoring control of a hub apparatus in a CATV transmission method is performed without using an optical transmitter for monitoring control and without increasing the number of optical fibers. Provide a way.

  An embodiment is shown in FIG. The CATV monitoring system and CATV monitoring method shown in FIG. 1 includes a center 101, a hub device 103, a closure 104, a node device 102, and the like, and is connected to a subscriber home device 106 via a coaxial transmission line 105. Applied to the system

In these system components, the center 101 includes an optical transmitter, an optical receiver, a switching device, an N-wave WDM, an optical branching device 110, and the like.
The hub device 103 includes an optical receiver, a switch, an optical transmitter, a supervisory controller 107, an optical splitter 108, an optical coupler 109, and the like.
The closure 104 has an N branching device.
The node devices 1 to N (102) include an optical receiver, an optical transmitter, and the like.
The subscriber premises apparatus 106 includes an STB (set top box), a TV, a CM (cable modem), a PC (personal computer), and the like. Details of these configurations will be described below.

  In the CATV monitoring system shown in FIG. 1, a monitoring controller 107 is mounted inside the hub device 103 for the purpose of remotely monitoring and controlling the hub device 103 from the center 101. The monitoring controller 107 in the hub device 103 receives the downlink monitoring control signal from the output of the switch, and once transmits the uplink monitoring control signal to the switch output unit.

  The downstream optical transmitter in the hub device 103 is prepared in advance so that the downstream CATV signal and the upstream monitoring control signal can be electro-optically converted. However, this preparation is a minor change even if the use frequency band is close and needs to be changed. Then, a part of the CATV optical signal that is the output of the downstream optical transmitter is branched by the optical branching unit 108 in the hub device 103. The branched CATV optical signal includes an upstream monitoring control signal, which is combined with the upstream CATV optical signal by the optical coupler 109 in the hub or input to an unused wavelength port of the N-wave WDM filter. When the optical coupler 109 combines with the upstream CATV optical signal, the wavelength is set to a wavelength other than the upstream CATV optical signal wavelength.

  In the center 101, the wavelength light including the uplink supervisory control signal is branched by the intra-center optical branching device 110 or the N-wave WDM filter, and is received by the (N + 1) th optical receiver.

It is a block diagram of the communication system applied to the CATV monitoring system and CATV monitoring method of this invention. The structural example of the HFC system of a prior art example is shown. The structural example of the HFC system of a prior art example is shown. The structural example of the HFC system of a prior art example is shown. The structural example of the HFC system of a prior art example is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Center 102 Node apparatus 103 Hub apparatus 104 Closure 105 Coaxial transmission line 106 Subscriber home apparatus 107 Monitoring controller 108,110 Optical branching unit 109 Optical coupler

Claims (6)

And cell pointer, and the front Symbol hub lies between the center and the node device unit, and a closure for an optical signal of the hub device comprises a N divider by N branches connected between the N of the node device, Tokoro a constant customer premises communications equipment and a node device newly connected, in a CATV monitoring system Ru provided with,
A monitoring controller is mounted inside the hub device, and remote monitoring control from the center of the hub device is performed,
The hub device has an optical transmitter and an optical branching unit,
The optical transmitter electro-optically converts a downstream CATV signal and an upstream monitoring control signal,
The CATV monitoring system , wherein the optical branching device branches a part of the output of the optical transmitter so as to include the uplink monitoring control signal and sends the branched signal to the center .   2. The CATV monitoring according to claim 1, wherein the communication equipment at the subscriber's home includes any of STB (set top box), TV, CM (cable modem), and PC (personal computer). system. The hub device has an optical coupler,
Said optical coupler, according to claim 1 or 2, characterized in that sending or bind upstream CATV optical signal, and input to the wavelength unused ports of N wave WDM filter into the center part of the output The CATV monitoring system according to any one of the above. The uplink monitor control signal, when combined with the upstream CATV optical signal by said optical coupler, a wavelength other than the uplink CATV optical signal wavelength, CATV according to claim 1, wherein the 3 in that Monitoring system. A subscriber's home communications equipment and the node device and the hub device is connected, and the hub device and the center is a C ATV monitoring method that are connected to each other,
A monitoring controller is mounted inside the hub device,
The optical transmitter in the hub device performs electro-optical conversion between the downstream CATV signal and the upstream monitoring control signal,
An optical branching device in the hub device branches a part of the output of the optical transmitter so as to include the upstream monitoring control signal and sends it to the center,
A CATV monitoring method, wherein the center performs remote monitoring control of occurrence of communication abnormality based on the electro-optic converted signal. 6. The CATV monitoring method according to claim 5, wherein the CATV optical signal is combined with an upstream CATV optical signal or input to an unused wavelength port of an N-wave WDM filter and a part of the output is transmitted to the center .

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