Telecommunications – Carrier wave repeater or relay system – Monitoring
Reexamination Certificate
2000-03-29
2002-12-10
Vo, Nguyen T. (Department: 2682)
Telecommunications
Carrier wave repeater or relay system
Monitoring
C455S067150, C455S024000
Reexamination Certificate
active
06493537
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 11-093960, filed Mar. 31, 1999, the entire contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
The present invention relates to, for example, a radio repeater device which relays between a base office and a vehicular terminal in a communication method of an FDMA method.
The current service system of the radio base station is as follows. Digital and the analog cable signals are converted into the base band which should be made a radio, and is digitized by the time-division and the FDMA (Frequency-Division Multi-Access) method. The multiple radio communication is performed by the number of channels corresponding to the office line.
The radio base station is set through the minute field examination, and the approach line design and the transmission propagation examination. However, the region to which service other than coverage are not received as shown in
FIG. 1
exists in the vehicular communication. This region is called “Blind zone”.
The radio repeater device enables the communication between the vehicular terminal in the blind zone and the above-mentioned radio base station. Therefore, this radio repeater device is a specification of government-managed or based on this.
The vehicular communication can be called public works, and, naturally, the radio repeater device to which the evil is given since the evil is not given to this communication network to this communication network should not be set up.
However, even if the radio repeater device of the operation between the base stations without trouble at time when it is set up, thereafter, the evil is occasionally caused for the communication network by the change in the environment in the surrounding. This cause will be explained referring to FIG.
2
.
To enable the communication between base station
15
and vehicular terminal
25
, the radio repeater device has a first antenna
10
(hereafter, called as “external antenna” for convenience' sake) and a second antenna (hereafter, called as “internal antenna” for convenience' sake) set up in the blind zone as shown in FIG.
2
. The blind zone is solved by being possible to communicate mutually by sending and receiving wave with each of antennas
10
and
25
, and base station
15
or vehicular terminal
25
. In addition, this radio repeater device has first and second antenna shared devices
31
and
36
, first and second band-pass filters
32
and
37
, and first and second amplifiers
33
and
38
.
Here, the signal from the base station received by external antenna
10
is input to first shared device
31
. Next, only the signal of the desired frequency can pass by first filter
32
. Thereafter, the reception signal amplified with first amplifier
22
is input to second shared device
36
, the signal is sent to internal antenna
20
, and the signal is sent from internal antenna
20
to vehicular terminal
25
. The signal from vehicular terminal
25
is received with internal antenna
20
, and processed with second filter
37
and second amplifier
38
through second shared device
36
as well as the signal received with external antenna
10
. The signal received from first shared device
31
to external antenna
10
with internal antenna
20
is sent to base station
15
.
Thus, the communication of vehicular terminal
25
in the blind zone becomes possible.
However, the radio repeater device operates same as the oscillation circuit when the signal from vehicular terminal
25
reaches external antenna
10
, as a result, the phenomenon in which the radio repeater device is saturated and oscillates occurs. Therefore, the following disadvantages are occurred. Use of vehicular terminal
25
in the circumference according to the concerned radio repeater device becomes impossible. The relay of other radio repeater devices may be obstructed by generating the noise signal from external antenna
10
or internal antenna
20
caused by the oscillation.
It is necessary to prevent the signal from vehicular terminal
25
from reaching an external antenna not to occur this disadvantage. However, at first, even if it is a structure that the signal of vehicular terminal
25
does not reach an external antenna, the leakage of the relay carrier etc. can happen by a remarkable change in the environment in the surrounding according to the building construction others and the earthquake accident, etc.
As described above, the conventional radio repeater device has the disadvantage that the radio repeater device oscillates because of reaching the signal from vehicular terminal
25
to an external antenna of the radio repeater device.
BRIEF SUMMARY OF THE INVENTION
An object of the present invention is to provide a radio repeater device which solves problem because of oscillation of the radio repeater device caused by leakage of relay carrier etc. etc.
The present invention adopts the following means to solve the above-mentioned problem.
The radio repeater device, which can mutually communicate by relay of a vehicular terminal with a base station, according to the present invention is characterized by comprising: a first antenna to communicate with the base station; a second antenna to communicate with the vehicular terminal; and a repeater section which is connected with the first antenna and the second antenna, and to relay the base station and the vehicular terminal to be able to communicate therebetween, wherein when the first antenna receives the signal from the vehicular terminal, an operation of at least the repeater section is stopped. Here, stop of the operation of the repeater section is performed by stopping a supply of a power supply to the repeater section.
Specifically, the radio repeater device, which can mutually communicate by relay of a vehicular terminal with a base station, according to the present invention is characterized by comprising: a repeater section which can communicate and is the relay of the base station and the vehicular terminal; a pilot signal generation section which sends the pilot signal for the monitor to the repeater section; and a reception controller by which the signal from the repeater section is input, and the operation of the repeater section is stopped at least when intensity is larger than predetermined signals which become standards. Another radio repeater device, which can mutually communicate by relay of a vehicular terminal with a base station, according to the present invention is characterized by comprising: a first antenna to communicate with the base station; a second antenna to communicate with the vehicular terminal; a repeater section which is connected with the first antenna and the second antenna, and to relay the base station and the vehicular terminal to be able to communicate therebetween; and a stop section, when the first antenna receives the signal from the vehicular terminal, to stop an operation of at least the repeater section.
In above-mentioned radio repeater device, preferable manners are as follows.
(1) The pilot signal generation section which sends a pilot signal for a monitor to the repeater section is further provided.
(2) The stop section comprises a reception controller which inputs a signal from the repeater section and stops an operation of at least the repeater section when intensity of the input signal is larger than a predetermined signal which is a standard signal.
(3) The reception controller comprises a comparator which compares the input signal and the predetermined signal and outputs a result thereof and a switch which turns off a power supply of a power supply section which supplies a power supply to the repeater section based on the comparison result.
With above-mentioned configuration, even when the signal from the vehicular terminal leaks to outside and is received by the external antenna, when the signal intensity of the repeater section becomes larger than predetermined intensity (that is, when it becomes a stat
Harada Industry Co. Ltd.
Nguyen Duc
Pennie & Edmonds LLP
Vo Nguyen T.
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