JP2008294848A - Optical transmission system, slave station device and alarm generation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical transmission system for relay transmission, a slave station device, and an alarm generation method capable of transmitting an alarm of abnormality of a slave station to the master station side without complicating the slave station. <P>SOLUTION: A monitor control part 32 of the slave station 3 monitors an operation of an RF part 31, when the abnormality is detected, turns a power source of the RF part 31 off by a switch 33 instead of abnormality alarm. Then, a current monitor 28 of a relay device 2 which monitors supplied current to the slave station 3, when the supplied current decreases from a specified value, outputs an alarm to a monitor control part 26, after that, the monitor control part 26 judges that the slave station 3 is abnormal and transmits the alarm toward the master station via a transmission processing part 25. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical transmission system that relays a radio signal by optical fiber transmission, a slave station device, and an alarm generation method.

  In the mobile phone system, in a tunnel, an underground shopping center, a building, or the like, a radio wave from the mobile phone base station is insensitive and the mobile phone terminal cannot communicate in that area. As a measure to eliminate such dead areas, a slave station is installed in the dead area, and the mobile phone base station converts the radio signal of radio waves wirelessly communicated with the mobile phone terminal into an optical signal and is installed on the mobile phone base station side. There is a ROF (Radio Over Fiber) system in which relay transmission is performed between a master station and a slave station, and the slave station reconverts to radio waves for communication.

  In a high-rise building, the ROF system is provided with a slave station as a dead area countermeasure for each floor and each zone, so the number of units increases and the power consumption increases. The operation status of each slave station is monitored by an internal monitoring circuit (BITE function: Built In Test) of each slave station. When an abnormality occurs, an alarm signal is superimposed on an optical signal obtained by converting a radio signal to the master station. It is transmitted (for example, Patent Document 1) or transmitted by OW (order wire) or the like separately laid.

Conventional alarm transmission methods require a low-frequency pilot signal generator, a multiplexing circuit for transmitting and receiving alarm signals, an interface, etc. There is a problem that power consumption increases as well.
Japanese Patent Laid-Open No. 2006-24584 (page 9, FIG. 1)

  Conventional alarm transmission methods require a low-frequency pilot signal generator, a multiplexing circuit for transmitting and receiving alarm signals, an interface, etc. There is a problem that power consumption increases as well.

  The present invention has been made to solve the above problem, and an optical transmission system, a slave station apparatus, and a warning generation method capable of transmitting an alarm for notifying a slave station of an abnormality of a slave station without complicating the slave station The purpose is to provide.

  In order to achieve the above object, an optical transmission system according to the present invention provides an optical signal transmitted from a base station to a mobile communication terminal via an antenna of a slave station device and transmitted from the master station to the slave station. In an optical transmission system that converts and relays the signal into a signal, when the wireless signal is input / output to / from a relay device and the RF processing means transmits and receives, and the operation of the RF processing means is detected and an abnormality is detected, At least one slave station including a monitor / control unit that turns off power supply to the RF processing unit that is fed from the relay device, a feeding unit that feeds power to each of the slave stations, and a current to be fed When the monitoring power is reduced below a predetermined power supply condition, the radio signal and the monitoring control means for determining that the slave station is abnormal and generating an alarm to the master station and the master station Light signal with alarms superimposed Characterized by comprising a relay device and a communication means for transmitting converted to.

  The slave station apparatus of the optical transmission system according to the present invention converts a radio signal transmitted / received between the base station and the mobile communication terminal via the antenna of the slave station apparatus into an optical signal directed to the slave station by the master station. In the slave station device of the optical transmission system, the relay device re-converts the optical signal to and from the master station into an electrical signal that is input to and output from the slave station and supplies power to the slave station. When a radio signal is input / output to / from the relay apparatus, the RF processing means for transmitting and receiving, and the operation of the RF processing means is monitored to detect an abnormality, the power supplied from the relay apparatus is A slave station apparatus for an optical transmission system, comprising: monitor / control means for reducing power consumption of the own apparatus by turning it off without supplying it to the processing means.

  Further, the alarm generation method of the optical transmission system of the present invention comprises a master station, a slave station, and a relay device, and a radio signal transmitted and received by a base station to and from a mobile communication terminal via the antenna of the slave station. In the alarm generation method of the optical transmission system in which the master station converts and relays the optical signal to the slave station, the slave station inputs / outputs the radio signal to / from the repeater and the radio When the operation of the RF processing means for transmitting / receiving a signal to / from the mobile communication terminal is monitored and an abnormality is detected, the power supply to the RF processing means fed from the relay apparatus is turned off, and the relay apparatus If the current supplied to the slave station is monitored and decreases below a predetermined power supply condition, the slave station determines that the slave station is abnormal and generates an alarm to the master station. Between the radio signal and the alarm. Wherein the transmitting and receiving converted to optical signals.

  According to the present invention, it is possible to provide an optical transmission system, a slave station apparatus, and an alarm generation method capable of transmitting an alarm for notifying the master station of an abnormality of the slave station without complicating the slave station.

  Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a configuration diagram of an optical transmission system according to an embodiment of the present invention.
In FIG. 1, an optical transmission system includes a master station 1 that transmits and receives radio signals to and from a mobile communication base station, a relay device 2 that inputs and outputs an optical signal converted from the radio signal to and from the master station 1, and a relay device. 2 is provided with a plurality of slave stations 3a to 3n that transmit and receive a radio signal re-converted into an electrical signal by the relay device 2 and communicate with the mobile communication terminal via the antenna 30.

  The relay device 2 includes a slave station power source that performs mutual conversion of optical-electrical signals and supplies power to the slave station 3, and supplies power to the slave station by a coaxial cable or a power line. Hereinafter, the operation of the optical transmission system will be described by taking as an example the case where the coaxial cable also serves as the power cable.

FIG. 2 is a functional block diagram for explaining the operation of the relay apparatus and the slave station according to the embodiment of the present invention.
In FIG. 2, the relay device 2 receives and transmits optical signals with the master station 1, the O / E 21, E / O 22, the reception processing unit 24, the transmission processing unit 25, and the relay device 2 perform internal operation processing. A supervisory control unit 26 for controlling, a slave station power feeding unit 27 for converting and generating a required power source from a power feeding device (not shown) to a slave station, a current monitor 28 for monitoring the feeding current, and a coil for cutting high frequency components by the power source L, a band pass filter 231 to 234, a duplexer d for branching a signal transmitted and received between the relay apparatus 2 and the slave station, an amplifier 241 for amplifying a radio signal output to the slave station 3 via the band pass filter 232, and , And an amplifier 234 for amplifying a radio signal input from the slave station 3.

  The band-pass filters 231 and 234 pass signals of frequencies at which the monitoring control signals input and output by the monitoring control unit 26 are transmitted to and received from the master station. A capacitor C connected to the output of the duplexer d is for cutting the DC component of the power supply to be fed.

  In FIG. 2, the slave station power supply unit 27 is described as being provided individually for each of the slave stations 3 a to 3 n, but may be shared by a plurality of slave stations 3.

  Between the relay device 2 and the slave station 3, a radio signal and power supplied to the slave station 3 are exchanged by the coaxial cable Cx.

  The slave station 3 processes the radio wave transmitted / received from the antenna 30 and inputs / outputs the signal to / from the relay device 3. The monitor unit 32 monitors and controls the operation of the RF unit 31. And a switch 33 for turning on and off the power supplied to the power source, and a coil L and a capacitor C similar to those of the relay device.

  The RF unit 31 demultiplexes and multiplexes radio waves and radio signals transmitted and received via the antenna 30 by the duplexer d, and the transmitter (TX) t and the receiver (RX) r perform radio wave transmission and reception processing.

FIG. 3 is a functional block diagram for explaining an example of operations of a conventional relay device and slave station.
In FIG. 3, the description of the same parts as those shown in FIG. 2 is omitted, and only the parts different from the embodiment will be described. First, in the slave station 3X, the RF unit 310 is separated into a transmission system and a reception system by a duplexer d.

  The reception system includes a monitor signal transmission unit g that reports the operation of the RF unit 310 to the radio signal from the receiver (RX) r. The radio signal enters one input of the hybrid h through the bandpass filter fr and is input to the reception signal input terminal of the duplexer d on the relay device 2X side.

  The monitor signal is input to the other input terminal of the hybrid h so that the pilot signal is subjected to predetermined modulation or the like by the monitor signal sending unit g and becomes monitor information so as to be superimposed on the radio signal received through the bandpass filter fg. The output is input to the reception signal input terminal of the duplexer d. If there is an abnormality in the RF unit 310, the monitor signal is an alarm.

  The high frequency signal in which the radio signal from the coupling terminal of the duplexer d and the monitor information are superimposed is output to the coaxial cable Cx via the DC cut capacitor C. The monitor control unit 320 monitors the monitor signal from the RF unit 310 and outputs a control signal or the like to the RF unit 310 via the switch 330 if there is an abnormality.

  The relay device 2X receives high frequency information from the slave station 3X via the coaxial cable Cx. The high-frequency signal input through the capacitor C of the relay device is further amplified by the duplexer d and the reception amplifier 242, and after passing through the hybrid, is input to the band-pass filter fg and the band-pass filter fr again.

  The output of the bandpass filter fg is input to the detection unit (DET) dt, restored to the monitor signal (alarm) after detection, and output to the monitoring control unit 260. The monitoring control unit 260 outputs the monitor signal and alarm to the transmission signal processing unit 25. The transmission processing unit 25 uses the monitor signal and alarm as a predetermined high-frequency signal via the band-pass filter 233, and is combined with the radio signal fr via the band-pass filter 234 in a hybrid manner.

  This combined signal is converted into an optical signal by E / 022, and transmitted to the master station 1. On the master station 1 side, the radio signal and the monitor signal are processed in a predetermined procedure after being converted again into an electric signal.

  As described above, in the conventional example, the RF signal 11 of the slave station 3 requires the monitor signal sending part g and the bandpass filters fg and fr. Similarly, the relay apparatus 2 also has the bandpass filters fg and fr. In addition to being required, DETdt is required, which increases the circuit scale and power consumption.

  Returning again to FIG. In FIG. 2, the monitor control unit 32 determines whether there is an abnormality from the monitor signal input to the RF unit 31, and if it is abnormal, operates the switch 33 and turns off the power supply to the RF unit 11. . Conventionally, a monitor (alarm signal) for notifying an abnormality has been generated and transmitted by the slave station 3x, but in this embodiment, the monitor signal is not generated, but instead, the power supply power is simply turned off. I do. As a result, in the current monitor 28 of the relay apparatus 2, the output current from the slave station power supply unit 27 decreases, for example, from 1 A (ampere) to 1 A as the average current.

  The current monitor 28 outputs the monitor current value to the monitor control unit 26. However, the monitor control unit 26 reduces the output current, in other words, a predetermined level or a level difference (for example, a current consumption value of 1.. 2A, or a difference in level of 0.8A), when it is detected that the current consumption of the slave station 3 decreases, the slave station (for example, 3a) is determined to be abnormal, and the master station via the transmission processing unit 25 is determined. An alarm is output to station 1. This alarm is transmitted together with identification information indicating which slave station (for example, 3a) is abnormal, but it may be an alarm merely indicating that any of the slave stations 3 is abnormal.

  In this method, the abnormality is notified by reducing the current consumption of the power source without using the monitor signal sending part g and the band pass filters fg and fr of the conventional slave station 3X, so the circuit scale does not increase, In addition, the power consumption of the slave station 3 during normal operation can be kept low.

  When the monitor control unit 32 detects an abnormality in the RF unit 11, the power supplied (hereinafter referred to as a power source) is not simply turned off. By combining the OFF time lengths so as to be unique to each slave station, failure determination can be performed even if the slave station power supply unit 27 and the current monitor 28 are shared by a plurality of slave stations.

  That is, unless a failure or abnormality of the slave station 3 occurs at the same time, the monitor control unit 26 or the current monitor 28 stores the combination pattern for each slave station by storing the abnormal slave station 3 from the combination of the on / off times of the power source. By comparing with the monitoring result, it is possible to identify which slave station is faulty. And since the monitor control unit 32 of the slave station 3 can also be realized by a simple timer circuit, this on-off repetition does not increase the circuit scale and power consumption of the slave station 3.

  The present invention may change or combine the combination of the configurations and the processing procedure without departing from the gist of the above description. For example, the relay device and the slave station may be integrated. Alternatively, the master station and the relay device may be integrated, signal transmission may be performed using an optical signal between the relay device and the slave station, and a power cable may be provided separately.

  In the above description, the coaxial cable serves as the signal line and the power line. However, the present invention can be applied to independent cables.

1 is a configuration diagram of an optical transmission system according to an embodiment of the present invention. The functional block diagram explaining the operation | movement of the relay apparatus and slave station concerning the Example of this invention. The functional block diagram explaining an example of operation | movement of the conventional relay apparatus and a slave station.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Master station 2 Relay apparatus 24 Reception process part 25 Transmission process part 26 Monitoring control part 27 Slave station electric power feeding part 28 Current monitor 3 Slave station 31 RF part 32 Monitor control part 33 Switch Cx Coaxial cable

Claims (7)

In an optical transmission system in which a base station converts a radio signal transmitted / received to / from a mobile communication terminal via an antenna of a slave station device into an optical signal directed to the slave station and relays it,
RF processing means for inputting / outputting the radio signal to / from the relay device and transmitting / receiving the radio signal, and when an abnormality is detected by monitoring the operation of the RF processing means, to the RF processing means fed from the relay device At least one slave station comprising monitoring and control means for turning off the power supply of
Power supply means for supplying power to each slave station, and monitoring to generate an alarm to the master station by determining that the slave station is abnormal when the supplied current is monitored and the current is reduced below a predetermined power supply current An optical transmission system comprising: a control unit; and a relay device including a communication unit that converts the radio signal and the alarm into an optical signal superimposed on the base station and transmits the optical signal. When the abnormality is detected, the monitor / control unit of the slave station turns off the pattern in a combination of an on time and an off time specific to each slave station,
In the case where the abnormality is detected by storing the unique pattern, the supervisory control unit determines a slave station in which the abnormality is detected by comparing the stored pattern with the monitored result. The optical transmission system according to claim 1.   The optical transmission system according to claim 2, wherein the power supply unit is a common power supply unit that supplies power to a plurality of slave stations. A base station converts a radio signal transmitted / received to / from a mobile communication terminal via an antenna of a slave station device into an optical signal directed to the slave station and relays it, and a relay device communicates with the master station. In the slave station apparatus of the optical transmission system for re-converting the optical signal into an electrical signal to be input / output to / from the slave station and supplying power to the slave station,
RF processing means for inputting / outputting the radio signal to / from the relay device and transmitting / receiving the radio signal;
A monitor / control unit that turns off the power supplied from the relay device without supplying power to the RF processing unit when the operation of the RF processing unit is detected and detects an abnormality, and reduces power consumption of the own device; A slave station device comprising: 5. The monitor / control means of the slave station, when the abnormality is detected, supplies the power in a pattern in which an on time and an off time specific to each slave station are combined. Slave station device. A radio signal transmitted and received by the base station to and from the mobile communication terminal via the antenna of the slave station device is converted into an optical signal that the master station is directed to the slave station. In the alarm generation method of the optical transmission system that converts and relays,
When the slave station detects an abnormality by inputting / outputting the radio signal to / from the relay device and monitoring the operation of the RF processing means for transmitting / receiving the radio signal to / from the mobile communication terminal , Turn off the power supply to the RF processing means fed from the relay device,
The relay device is
If the current supplied to the slave station is monitored and decreased below a predetermined supply current, it is determined that the slave station is abnormal, and an alarm is generated to the master station. An alarm generation method for an optical transmission system, wherein the radio signal and the alarm are converted into an optical signal superimposed and transmitted / received. The relay device supplies power to a plurality of slave stations in common, and when the abnormality is detected, the slave station supplies the supplied power in a pattern that combines on time and off time unique to each slave station. Turn it off
The relay device stores the unique pattern in advance, and when an abnormality is detected in the current supplied by the monitor, the slave station in which the abnormality is detected by comparing the stored pattern with the monitored result The method of generating an alarm for an optical transmission system according to claim 6, wherein:

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