Telecommunications – Radiotelephone system – Zoned or cellular telephone system
Reexamination Certificate
1998-03-27
2001-03-13
Nguyen, Lee (Department: 2683)
Telecommunications
Radiotelephone system
Zoned or cellular telephone system
C455S528000, C342S357490, C342S357490, C342S357490, C342S450000
Reexamination Certificate
active
06201973
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a mobile communications system and, in particular to a mobile communication apparatus having a transmission inhibition function.
2. Description of the Prior Art
With the wide use of high-tech gear such as computers and digital devices having microprocessors therein, there has been a growth in the case where operations of the high-tech gear are adversely affected by radio waves emitted from radio communication equipment such as mobile telephone terminals. Especially, in the case of hospital, it may be a serious problem.
As another example, in the case where assigned frequency bands vary from nation to nation in a region having the borders of a plurality of nations such as Europe, it is unlawful to transmit a radio signal within a different nation.
To prevent undesirable and illegal transmission as described above, there have been proposed several mobile communications systems and mobile terminals having a capability of inhibiting radio transmission.
In Japanese Patent Unexamined Publication No. 5-344050, a mobile communication apparatus is provided with a database storing transmission permitted areas and a location detector using a satellite communication system such as GPS (Global Positioning System). When it is located out of transmission permitted areas, the transmission operation is inhibited.
However, the mobile communication apparatus is not suitable for location detection of a relatively small area such as building location. Further, the mobile communication apparatus needs a GPS device as the location detector.
In a mobile communication system as disclosed in Japanese Patent Unexamined Publication No. 7-87568, a mobile terminal is provided with a database storing transmission and reception inhibition areas and a location detector using GPS. When the mobile terminal is located within a reception inhibition area, the system transmits a signal to the mobile terminal and thereby an audible alert is inhibited. As another system, a system side including base stations and a control center is provided with the database storing transmission and reception inhibition areas and the location detector. When the mobile terminal is located within a transmission inhibition area, the system side informs a user that the user is located in a transmission inhibition area and then the transmission operation is inhibited.
However, the system needs to transmit a message signal to the mobile terminal so as to inform the user of transmission or reception inhibition area. Further, the mobile terminal also needs a GPS device as the location detector.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a mobile communication apparatus which can achieve reliable transmission inhibition without transmitting any specific signal.
Another object of the invention is to provide a mobile communication apparatus which can detect the precise location thereof and achieve reliable transmission inhibition at a relatively small area such as a building location.
According to the present invention, a mobile communication apparatus including a transceiver for receiving and transmitting a radio signal for use in a plurality of service areas formed by a plurality of base stations is provided with a location calculator for calculating a location of the mobile communication apparatus within the service areas based on three radio control signals each received from a different base station. A plurality of transmission inhibition areas of data are stored and the transceiver in controlled depending on whether the location of the mobile communication apparatus is within one of the transmission inhibition areas.
The location calculator may be comprised of a detector for detecting a Doppler shift frequency of a radio control signal received from each of the three base stations. A distance between the mobile communication apparatus and each of the three base stations is calculated from the Doppler shift frequency of the radio control signal and the location of the mobile communication apparatus to determined from three distances calculated by the distance calculator.
The location calculator may be comprised of a detector for detecting reception time of a radio control signal received from each of the three base stations, wherein the radio control signal conveys transmission time information. A distance between the mobile communication apparatus and each of the three base stations in calculated based on time elapsed between transmission and reception of the radio control signal obtained from the reception time and the transmission time. The location of the mobile communication apparatus is determined from three distances calculated by the distance calculator.
REFERENCES:
patent: 5056106 (1991-10-01), Wang et al.
patent: 5442805 (1995-08-01), Sagers et al.
patent: 5548296 (1996-08-01), Matsuno
patent: 5629710 (1997-05-01), Sawada
patent: 5878330 (1999-03-01), Naumann
patent: 5943014 (1999-08-01), Gilhousen
patent: 5982324 (1999-11-01), Watters et al.
patent: 5-344050 (1993-12-01), None
McGuireWoods LLP
NEC Corporation
Nguyen Lee
LandOfFree
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