JP2002118518A - Radio relay amplification device and mobile communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive radio relay amplification device which is constituted of inexpensive photocouplers and switches, by a method wherein expensive laser diodes and a optical detection circuits are not used for a slave station. SOLUTION: In the radio relay amplification device, a master station 10 receives radio waves from a base station in a mobile communication system so as to be converted into a light signal, at least one slave station 20 converts the light signal into the radio waves so as to be transmitted to a portable terminal in the mobile communication system, and the state of at least one slave station 20 is transmitted to the master station 10 by the light signal. The amplification device is provided with a photocoupler 21 which distributes the light signal received by the slave station 20 from the master station 10, a slave-station control unit 26 which monitors the state of the slave station 20, and the optical switch 25 by which the output of the photocoupler 21 is transmitted to the master station 10 from the slave station 20 based on the control unit 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio relay amplifying device in a mobile communication system such as a radio pager and a portable telephone, and a mobile communication system using the same.

[0002]

2. Description of the Related Art FIG. 3 is a block diagram showing an example of the configuration of a conventional optical repeater disclosed in, for example, Japanese Patent Application Laid-Open No. 7-38506. This optical repeater includes amplifying sections 401 and 40.
2 respectively, the optical fiber amplifiers 411, 421
The optical signal input to the optical coupler 412 is split by the optical couplers 412 and 422 and is supplied to the photodetectors 414 and 424 to be converted into an electric signal. The alarm signal generators 415 and 425 are
The level of the optical signal is determined based on the level of the electrical signal given from 4, 424, and whether or not this level is equal to or higher than a predetermined level is monitored. The alarm signal generators 415 and 425 drive the laser diodes 416 and 426 to transmit an alarm signal of a predetermined pattern when the level of the optical signal is lower than a predetermined value. According to this optical repeater, the location of the failure can be easily determined. 417, 4 in the figure
18, 427 and 428 are optical switches, and 413 and 423 are optical couplers.

FIG. 4 is, for example, Japanese Unexamined Patent Application Publication No. 10-513.
FIG. 1 is a block diagram illustrating an example of a configuration of a conventional chromatic dispersion monitoring system for an optical transmission line disclosed in Japanese Patent Publication No. 81. This system comprises an optical receiver 536 and a demodulation means 53 for a received signal.
8, control means 540 for performing transmission control, a terminal station 502 including an optical transmitter 510, and an optical transmission line 506 including a line 512.
An optical repeater 503 including optical amplifiers 514 and 534;
An optical coupler 516 configured to split the received signal light into first and second split lights;
An optical receiver 518 for receiving the first split light, a spectrum detecting means 520 for receiving the second split light and detecting the spectrum of the signal light and the spectrum of the side band generated by the side band modulation instability, and the detection result Calculating means 524 for calculating a parameter related to chromatic dispersion of the line 512 based on the above, monitoring data generating means 528 for generating monitoring data from the calculating means,
30 and an optical transmitter 526. According to this chromatic dispersion monitoring system, it is possible to monitor chromatic dispersion of unstable sideband modulation.

[0004]

However, in the example of FIG. 3, a laser diode is used to send out an alarm signal. Further, in the example of FIG. 4, a laser diode is used in the modulation unit 530 of the first optical transmitter 510 and the second terminal station 504. As described above, an expensive laser diode is used for an optical repeater or an optical transmitter, and there is a problem in that the entire device becomes expensive and prevents cost reduction.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and comprises a low-cost optical coupler and an optical switch without using an expensive laser diode and a photodetection circuit in the slave station. It is an object of the present invention to provide a cost-effective and economical wireless relay amplifier.

[0006]

In order to solve the above-mentioned problems, a radio relay amplifying apparatus according to the present invention comprises a master station receiving radio waves from a base station of a mobile communication system, converting the radio waves into an optical signal, A wireless relay amplifying device in which at least one slave station converts the optical signal into a radio wave and transmits the radio signal to a mobile terminal of the mobile communication system, and transmits a state of at least one slave station to the master station by an optical signal, An optical coupler that distributes an optical signal received by the slave station from the master station; a slave station control unit that monitors the status of the slave station; and an output of the optical coupler based on the slave station control unit. And an optical switch for transmitting the data to the master station.

Further, in the mobile communication system according to the present invention, the communication between the base station and the mobile station is performed via the above-mentioned radio relay amplifier.

According to the above-described wireless relay amplifying apparatus,
An inexpensive optical coupler and optical switch can be used in the slave station without using the above-mentioned expensive laser diode and photodetector circuit, and an economical wireless relay amplifier can be provided.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. Embodiment 1 FIG. FIG. 1 is a block diagram showing a configuration of the wireless relay amplification apparatus according to the first embodiment. The master station 10 and the slave station 20 are connected by a first optical fiber cable 30 and a second optical fiber cable 31. The master station 10 includes a receiving antenna 11, a first bandpass filter 12, a first amplifying unit 13, an E / O unit 14, a photodiode 15,
It is composed of a master station control unit 16. The slave station 20 includes an optical coupler 21, an O / E unit 22, a second amplifying unit 23, a second
Bandpass filter 24, optical switch 25, slave station control unit 2
6 and a transmission antenna 27. The first optical fiber cable 30 is connected to the E / O unit 1 of the master station 10.
4 and the optical coupler 21 of the slave station 20, and the second optical fiber cable 31 is connected to the photodiode 15 of the master station 10.
And the optical switch 15 of the slave station 20 are connected.

FIG. 1 illustrates a case where there are two or more slave stations. Thus, the wireless relay amplification device of the present invention
It has at least one slave station.

Next, the operation of the first embodiment will be described. The reception antenna 11 is installed at a point where radio waves from the base station can be received, for example, at the top of a mountain, and outputs a reception signal to the first bandpass filter 12. The first band filter 12 selects a used band signal of the high frequency signal of the input received signal. The received signal selected by the first band-pass filter 12 is power-amplified by the first amplifying unit 13 and the E / O unit 14
Output to The E / O unit 14 converts the input electric signal into an optical signal and outputs the optical signal to the optical coupler 21 through the first optical fiber cable 30. Here, the E / O unit 14
Specifically, it is a circuit that uses a laser diode and performs direct luminance modulation and converts it into an optical signal.

The optical coupler 21 converts the input optical signal into an O / O signal.
Output to E section 22. The O / E unit 22 converts the input optical signal into an electric signal and outputs the electric signal to the second amplifying unit 23. O
The / E section 22 specifically uses a photodiode. The second amplifier 23 power-amplifies the input electric signal and outputs the electric signal to the second bandpass filter 24. The second bandpass filter 24 attenuates harmonics of the input signal and unnecessary noise outside the band, and outputs the result to the transmission antenna 27. The transmitting antenna 27 is installed at a point where it can be transmitted to a desired area, and transmits an input signal as a radio wave to a portable terminal existing in the desired area. The desired area is specifically a service blind zone of the base station.

The slave station control unit 26 is provided with a second amplification unit 23
And the like, the optical switch 25 is turned on if the state of the second amplifier 23 is normal, and the combined output of the optical coupler 21 is transmitted to the photodiode 15 of the master station 10 via the second optical fiber cable 31. Output. If the state of the second amplifier 23 is abnormal, the slave station controller 26 turns off the optical switch 25
FF.

The photodiode 15 detects an output signal from the optical switch 25 of the slave station at the master station, and outputs the signal to the master station control unit 16. The master station controller 16 monitors the status of the slave station from the output signal. Also, it monitors the alarm of the first amplification unit 13 and the alarm of the E / O unit 14.

In this embodiment, since the status of the slave station is reported to the master station, an optical signal output from the master station is used. Therefore, it is not necessary to use a laser diode in the slave station. When an optical signal is not normally input from the master station to the slave station, a normal optical signal is not output to the master station, so that the slave station does not need a light detection circuit.

Embodiment 2 FIG. 2 is a block diagram illustrating an example of a mobile communication system using the wireless relay amplification device. This system includes a base station 80, at least one wireless relay amplifying device 81, and at least one portable terminal 82 for one wireless relay amplifying device. The wireless relay amplifying device 81 includes a master station 83 and at least one slave station 84. The master station and each slave station are connected by an optical fiber cable, and have a maximum distance of about 2 km.

The wireless relay amplifying device 81 may use the first embodiment or may use the second embodiment. When the first embodiment is used, the master station 83 has the same configuration as the master station 10, and the slave station 84 has the same structure as the slave station 20. When the second embodiment is used, the master station 83 has the same configuration as the master station 50, and the slave station 84 has the same configuration as the slave station 60.

Next, the operation of FIG. 2 will be described. First, the operation of the downlink from the base station 80 to the portable terminal 82 will be described. Base station 80 transmits a radio wave to master station 83.
The master station 83 converts the received electric signal into an optical signal and transmits the optical signal to the slave station 84 via an optical fiber cable. The slave station 84
The received optical signal is converted into an electric signal and transmitted to the portable terminal 82 as a radio wave. In the case where the second embodiment is used, the operation of the uplink from the mobile terminal 82 to the base station 80 will be described. The portable terminal 82 transmits a radio wave to the slave station 84. The slave station 84 converts the received electric signal into an optical signal,
The data is transmitted to the master station 83 via an optical fiber cable. Master station 83
Converts the received optical signal into an electric signal and transmits the electric signal to the base station 80 as a radio wave.

[0019]

As described in detail above, according to the present invention,
An economical wireless relay amplifier can be provided by using an inexpensive optical coupler and an optical switch without using an expensive laser diode and an optical detection circuit.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a wireless relay amplification device according to Embodiment 1 of the present invention.

FIG. 2 is a block diagram showing a mobile communication system according to Embodiment 2 of the present invention.

FIG. 3 is a block diagram illustrating an example of a configuration of a conventional optical repeater.

FIG. 4 is a block diagram showing an example of a configuration of a conventional chromatic dispersion monitoring system for an optical transmission line.

[Explanation of symbols]

10,83 master station, 11 receiving antenna, 12 first bandpass filter, 13 first amplifier, 14 E / O section, 15
Photodiode, 16 master station control unit, 20, 84
Slave station, 21 optical coupler, 22 O / E section, 23 second amplification section, 24 second bandpass filter, 25 optical switch, 2
6 slave station control section, 27 transmitting antenna, 30, 32 first optical fiber cable, 31 second optical fiber cable, 80 base station, 81 wireless relay amplifying device, 82
Mobile terminal.

Continued on the front page (72) Inventor Yoichi Okubo 3-14-20 Higashinakano, Nakano-ku, Tokyo Kokusai Denki Co., Ltd. F-term (reference) 5K002 BA04 BA06 DA12 DA41 EA05 FA01 5K042 AA06 CA15 CA19 DA16 EA01 EA14 FA15 FA21 FA25 HA13 JA01 NA01 5K067 AA41 BB02 DD44 EE02 EE06 EE10 LL05

Claims (2)

[Claims] 1. A master station receives a radio wave from a base station of a mobile communication system and converts it into an optical signal, and at least one slave station converts the optical signal into a radio wave to a mobile terminal of the mobile communication system. A wireless relay amplifying device for transmitting and transmitting a state of at least one of the slave stations to the master station by an optical signal, wherein an optical coupler for distributing an optical signal received by the slave station from the master station; A wireless relay amplification device, comprising: a slave station control unit that monitors a state; and an optical switch that transmits an output of the optical coupler from the slave station to the master station based on the slave station control unit. . 2. A mobile communication system, wherein communication between a base station and a mobile station is performed via the wireless relay amplifying device according to claim 1.