Telecommunications – Transmitter and receiver at separate stations – Having measuring – testing – or monitoring of system or part
Reexamination Certificate
1999-05-13
2001-11-06
Le, Thanh Cong (Department: 2684)
Telecommunications
Transmitter and receiver at separate stations
Having measuring, testing, or monitoring of system or part
C455S456500, C455S067700, C342S378000, C342S451000
Reexamination Certificate
active
06314271
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method and an apparatus for performing radio monitoring, and more particularly, to a method and an apparatus for performing radio monitoring in a certain area where radio waves are used at a relatively high density to prevent the generation of radio interference.
2. Description of the Prior Art
With development of a mobile communication system, a wireless local area network (LAN) or the like, radio waves are used at a high density in urban areas and limited frequency resources are shared. Consequently, radio interference is generated to the extent that it can not be negligible.
When a radio wave source which causes the radio interference is specified, a sensor station (monitoring station) is conventionally placed in each of a plurality of points, the Yagi-Uda antenna or a goniometer is used in each sensor station to observe a direction in which a radio wave comes from the radio wave source, and the radio wave incoming directions at respective sensor stations are plotted on a map to specify the position of the radio wave source based on the position of an intersection point of the directions.
Since the above-mentioned conventional method specifies the position of the radio wave source based on the intersection point of the incoming directions of the radio wave observed in the sensor stations, at least two sensor stations are required. Thus, this method has a disadvantage that it can specify only a radio wave source of a relatively strong radiation receivable simultaneously at two or more sensor stations. Additionally, when two or more radio wave sources are present at positions near to each other at the same frequency band, radio waves transmitted therefrom can not separated for observation, thereby obtaining a result of observing the incoming radio wave direction in the sensor station in the form of a synthesized radio wave. Thus, it may be impossible to estimate each position of the radio wave source in this case.
The radio interference in urban areas may frequently occur even between radio wave sources which are close to each other and emit relatively weak radio waves. Also, the sensor stations can not be placed at a high density in consideration of costs or the like. Consequently, according to the conventional method, it is impossible to completely specify the generation source of the radio interference and it is extremely difficult to find the cause of the radio interference.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a method for visualizing radio waves in a certain area which can use only one sensor station to specify the positions of a plurality of radio wave sources operating in the same frequency band and which can monitor a state of utilization of radio waves.
Another object of the present invention is to provide an apparatus for visualizing radio waves in a certain area which can use only one sensor station to specify the positions of a plurality of radio wave sources operating in the same frequency band and which can monitor a state of utilization of radio waves.
The first object of the present invention is achieved by a method for visualizing radio waves in a specific area for observing radio waves from radio wave sources to reconstruct a radio wave hologram to visualize distribution of the radio wave sources, the method comprising the steps of: providing one or more scanning antennas and a plurality of fixed antennas having different directions and/or positions in a sensor station; causing a signal received at the scanning antenna to interfere with a signal received at the fixed antenna for each of the fixed antennas to thereby obtain a complex scanning data matrix while the scanning antenna scans along a predetermined path; performing complex weighting addition processing for the complex scanning data matrix to reconstruct distribution of the radio wave sources.
The second object of the present invention is achieved by an apparatus for visualizing radio waves in a specific area for observing radio waves from radio wave sources to reconstruct a radio wave hologram to visualize distribution of the radio wave sources, the apparatus comprising: one or more scanning antennas for scanning along a predetermined path; a plurality of fixed antennas having different directions and/or positions; an interference unit for causing a signal received at each of the scanning antennas to interfere with a signal received at each of the fixed antennas to output an interference signal; a detector for complex detecting the interference signal to obtain a detection output; and operation means for temporally storing as a complex scanning data matrix the detection output for each combination of one of the scanning antennas and one of the fixed antennas and performing complex weighting addition processing for the complex scanning data matrix to reconstruct distribution of the radio wave sources.
According to the present invention, by employing the above-mentioned configuration, one sensor station can be used to separate radio wave sources extremely close to one another for observation, and plane distribution (two-dimensional distribution) and characteristic distribution of radio wave sources can be accurately obtained even in an area where radio waves are used at a high density.
REFERENCES:
patent: 5381444 (1995-01-01), Tajima
patent: 5455590 (1995-10-01), Collins et al.
patent: 5563909 (1996-10-01), Nakazawa
patent: 5689812 (1997-11-01), Takahashi
patent: 5734347 (1998-03-01), McEligot
patent: 5907578 (1999-05-01), Pon et al.
patent: 6070079 (2000-05-01), Kuwahara
patent: 6115614 (2000-09-01), Furukawa
patent: 2034554 (1980-06-01), None
Japanese Patent laid-open Publication No. 65406/1999.
Japanese patent Laid-open Publication No. 153725/1997.
Japanese Patent Laid-Open Publication No. 133721/1997.
Japanese Patent Application No. 317418/1997.
Advantest Corporation
Cong Le Thanh
Knobbe Martens Olson & Bear LLP
Tran Pablo
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