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Mobile communication system

  • US 6,459,905 B1
  • Filed: 07/07/1999
  • Issued: 10/01/2002
  • Est. Priority Date: 04/22/1998
  • Status: Expired due to Fees
First Claim
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1. A mobile communication system comprising:

  • a ground communication system, said ground communication system including a radio interface;

    a satellite communication system, said satellite communication system including a radio interface, said satellite communication system communicating with at least one satellite;

    a relaying apparatus for converting an RF signal in the satellite communication system into an RF signal in the ground communication system;

    a portable telephone;

    said portable telephone automatically switching between said ground communication system and said satellite communication system, wherein;

    while said ground communication system is not available; and

    said portable telephone is in a place where said satellite of said satellite communication system cannot be observed;

    a signal process operation, said signal process operation being switched in such a manner that;

    an RF signal from said satellite communication system is converted by said relay apparatus into an RF signal in said ground communication system, and is processed by said ground communication system, and both of an IF signal and a baseband signal are processed by said satellite communication system; and

    wherein said portable telephone includes;

    a commonly-used antenna for transmitting/receiving the signal of said ground communication system and also the signal of said satellite communication system;

    a duplexer connected to said commonly-used antenna, for duplexing transmission/reception signals;

    a first switch for switching an output of said duplexer;

    a satellite system receiving radio frequency unit connected to said first switch;

    a ground system receiving radio frequency unit connected to said first switch;

    a second switch connected to said satellite system receiving radio frequency unit and to said ground system receiving radio frequency unit;

    a receiving IF circuit connected to said second switch;

    a demodulator for demodulating an output of said receiving IF circuit;

    a baseband processing unit into which the demodulation output of said demodulator is entered;

    a modulator for modulating an output of said baseband processing unit;

    a transmitting IF circuit connected to said modulator;

    a synthesizer for supplying a local signal to said receiving IF circuit and to said transmitting IF circuit;

    a third switch connected to said transmitting IF circuit;

    a satellite system transmitting radio frequency unit connected to said third switch;

    a ground system transmitting radio frequency unit connected to said third switch;

    a fourth switch connected to said satellite system transmitting radio frequency unit and to said ground system transmitting radio frequency unit, whose output is supplied to said duplexer; and

    a CPU for controlling said first, second, third, and fourth switches in such a manner that the first and second switches are controlled so as to connect said ground system receiving radio frequency unit and said ground system transmitting radio frequency unit in response to a first control signal;

    said synthesizer produces a local signal suitably used to convert said ground system RF signal into an IF signal in response to a second control signal; and

    said demodulator and said modulator are controlled so as to be operable by the modulating/demodulating methods of said satellite communication system in response to a third control signal.

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