Telecommunications – Transmitter and receiver at separate stations – Having measuring – testing – or monitoring of system or part
Reexamination Certificate
2000-08-11
2004-02-10
Chin, Vivian (Department: 2682)
Telecommunications
Transmitter and receiver at separate stations
Having measuring, testing, or monitoring of system or part
C455S097000, C455S067130, C455S136000, C455S226100, C455S425000
Reexamination Certificate
active
06690921
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a receiving apparatus having an outdoor receiving unit, a base station apparatus using the same, and a radio communication system.
The outdoor receiving unit is mainly used as a receiving unit in the base station apparatus, in the mobile communication, and installed on the receiving antenna pylon. In this case, in order to transmit a signal which is caught by a receiving antenna installed on the receiving antenna pylon to a main apparatus on the ground, a long coaxial cable or the like must be employed. Since the receiving signal is attenuated by the coaxial cable, NF (noise figure) is deteriorated. Therefore, there is such a subject that, even if a receiving apparatus with good performance is provided as the receiving apparatus installed on the ground, good receiving sensitivity cannot be achieved.
In such case, such an approach is often employed that a low-noise receiving amplifier is provided in the neighborhood of the receiving antenna as the outdoor receiving unit to suppress the degradation of NF by the coaxial cable and thus attain the good receiving performance.
However, a location on which the outdoor receiving unit is installed is a top of the pylon. Thus, since the failure due to the thunderbolt is often caused or the receiving sensitivity is degraded at the time of the failure, the operation of the outdoor receiving unit must always be monitored and also the failure, if occurs, must be quickly detected. Nevertheless, there is such a subject that, since the installing location is the top of the receiving antenna pylon, maintenance and inspection operations at that location are difficult.
Therefore, in order to overcome these subjects, approaches described in the following have been known. As the abnormality monitoring apparatus for detecting the abnormality such as gain reduction of the outdoor receiving unit, breakdown of the parts, etc. in the prior art, the pilot signal level monitoring apparatus disclosed in Patent Application Publication (KOKAI) Hei 5-122170 has been known. This apparatus injects the pilot signal from the input side of the receiving amplifier, and then detects the pilot signal component on the output side of the receiving amplifier to get the gain of the receiving amplifier.
Also, like the distributing/synthesizing system disclosed in Patent Application Publication (KOKAI) Hei 9-135125, such a method has been known that the pilot signal is injected from the distributor on the input side of the receiving amplifier and then the gain of the receiving amplifier is monitored by comparing the pilot signal got from the output of the synthesizer on the output side of the receiving amplifier with the reference value to detect the abnormal operation.
In addition, like the power supply current transmitting system disclosed in Patent Application Publication (KOKAI) Hei 7-177082, such a method has been known that the consumption current of the receiving amplifier is monitored and then the failure of the receiving amplifier is informed the main apparatus by changing the power supply current supplied to the outdoor receiving unit when the abnormality of the current value is detected.
However, there are subjects described in the following in the systems in the prior art. According to the pilot injection system, the abnormality is detected when the detected voltage of the pilot signal component is lowered. In this case, the outdoor receiving unit is decided as the failure even if the pilot signal generating means is broken down and thus the signal level is lowered. Therefore, there is such a subject that, when the abnormality is to be detected by the main apparatus on the ground, it cannot be discriminated which failure of the receiving amplifier, the pilot signal generating means, or the transmitting means causes the above abnormality.
Also, in the pilot signal generating means, unless a means for holding the output level of the pilot signal is provided, the output level is apt to change according to the change in the ambient temperature, the change in the power supply voltage, etc. Because of the influence of such change, the level of the pilot signal to be received in the main apparatus is changed even when the gain of the outdoor receiving unit is normal. In addition, there is such a subject that, since the gain of the receiving amplifier is measured by measuring the absolute value of the level of the pilot signal in the main apparatus, the gain of the main apparatus cannot be precisely measured unless the insertion loss of the transmitting means, which transmits the signal from the outdoor receiving unit to the main apparatus, is precisely measured in installing the outdoor receiving unit to correct the level.
Further, in the distributing/synthesizing system in the prior art, there is such a subject that, since the abnormality is detected in the outdoor receiving unit, a means for transmitting the abnormality detection signal must be provided so as to transmit the abnormality detection to the main apparatus.
Furthermore, at the time of the failure of the outdoor receiving unit, not only monitoring the consumption current but also monitoring the gain of the receiving amplifier is effective to quantitatively grasp a degree of degradation of the receiving sensitivity due to the failure. In the power supply current transmitting system in the prior art, there are such subjects that, when the abnormality of the current is detected in monitoring the consumption current of the receiving amplifier, a degree of deterioration of the gain of the receiving amplifier cannot be grasped and also, when the gain of the receiving amplifier is reduced due to disconnection of the signal line for coupling the multi-stage amplifiers, such reduction in the gain of the receiving amplifier cannot be detected.
Moreover, under the condition the outdoor receiving unit is broken down, it is desired that the radio system can be employed until the repair is completed. When the receiving amplifier of the outdoor receiving unit is composed of the multi-stage amplifiers, generally the degradation of the receiving sensitivity is increased in the case where the preceding-stage receiving amplifier is broken down rather than the case where the succeeding-stage receiving amplifier is broken down. For this reason, there is such a subject that, when the outdoor receiving unit is out of order, a degree of degradation in the quality of communication can be grasped by detecting at which stage the amplifier is broken by using the main apparatus, nevertheless such grasp of degradation cannot be achieved in the power supply current transmitting system.
Also, there is such a subject that, since a plurality of signal sources must be built in the outdoor receiving unit to get a plurality of pilot signals by the outdoor receiving unit, a method of obtaining the pilot signal is difficult.
Also, in the pilot injection system in the prior art, the level of the signal being input into the receiving means must be adjusted according to difference in the length of the cable as the transmitting means in installing the system. As the adjusting method, an amount of attenuation is set by 1 dB step, for example, by the stepwise attenuating means connected to the cable, in compliance with an amount of attenuation detected from the cable length. Therefore, as the error in correcting the insertion loss of the cable, the error of ±0.5 dB is produced at maximum. As a result, there is such a subject that, in detecting the gain reduction, the detection precision is degraded owing to the influence of such error.
Also, if the failure detecting portion in the main apparatus is out of order, it is sometimes decided that the receiving amplifier has been broken down in the receiving unit which detects the abnormality of the outdoor receiving unit by detecting the pilot signal. Therefore, there is such a subject that, even if the amplifier of the outdoor receiving unit is normally operated and thus no degradation of the quality of communication is caused, such situ
Ikeda Kazuhiko
Ishii Koji
Morino Takayoshi
Nagayama Toshihiro
Takeyama Kazuhiko
Chin Vivian
Matsushita Electric - Industrial Co., Ltd.
Pearne & Gordon LLP
Tran Tuan
LandOfFree
Receiving apparatus, base station apparatus using same and... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Receiving apparatus, base station apparatus using same and..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Receiving apparatus, base station apparatus using same and... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3294031