Cellular radio telephone enhancement circuit

• US 4,849,963 A
• Filed: 10/15/1985
• Issued: 07/18/1989
• Est. Priority Date: 10/15/1985
• Status: Expired due to Term

• Current Assignee: Westinghouse Electric Company LLC (Brookfield Asset Management Incorporated), Mitsubishi Electric Corporation
• Original Assignee: Astronet
• Inventors: Kawano, Minori, Ferguson, James G., Ichinose, Tomoji
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): Kuntz, Curtis A.
• Application Number:
  US06/787,332
• Time in Patent Office: 1,372 Days
• Field of Search: 370/30, 370/31, 370/26, 370/75, 455/33, 455/9, 455/55, 455/53, 455/251, 455/17, 455/54, 455/56, 455/340, 455/15, 455/20, 379/59
• US Class Current: 370/279
• CPC Class Codes: H04B 7/15542 Selecting at relay station its transmit and receive resources selection of wireless resources by user or terminal H04W72/02; arrangements affording multiple use of the transmission path by two-dimensional division of the resources H04L5/0003, or by allocating sub-channels H04L5/003
• CPC Class Codes: H04B 7/2606 Arrangements for base station coverage control, e.g. by using relays in tunnels
• CPC Class Codes: H04W 16/26 Cell enhancers or enhancement, e.g. for tunnels, building shadow

Abstract

For use in a cellular radio-telephone system to enhance a signal from a cell site in an area shadowed by an obstruction such as a building or a mountain or the like, and to receive signals from subscribers in such areas, a cell enhancer includes bidirectional receivers, transmitters and amplifiers, the receivers and transmitters both including duplexer circuits for coupling signals in the proper up-link and down-link bands to the proper up-link and down-link antennas for transmission. Two embodiments of amplifiers are disclosed. A wideband amplifier network includes an input duplexer, a wideband amplifier with an attenuator, and an output duplexer, the duplexers coupling signals from both the up-link and down-link duplexer circuits to the amplifier for amplification. A narrow band network includes a plurality of amplifier modules each of which amplify only on one up-link and down-link channel assigned to the cell. A signal divider couples signals in the appropriate channels to the inputs of the corresponding modules, and a signal combining circuit receives signals from the modules to generate a composite signal for transmission by the up-link and down-link antennas. The enhancer further includes a control circuit responsive to signals from the cell site received through the amplifier for controlling the operations of the enhancer and for reporting to the cell site the status of the enhancer by transmitting signals through the enhancer.

Claims

1. For use in a cellular radio telephone system, a cell enhancer for amplifying duplex communications between a cell site and a subscriber in a selected region of a cell over a plurality of radio frequency channels comprising:

A. cell site communications means for receiving signals from and transmitting signals to the cell site over the plurality of radio frequency channels, comprising;

i. cell site antenna means for converting signals between electromagnetic signals from the cell site or the subscriber and electrical signals;

ii. cell site duplexer means for receiving the electrical signals from the cell site antenna means and directing them to a cell site duplexer output node and for receiving amplified output signals from a cell site duplexer input node for directing them to said antenna means for conversion to electromagnetic signals for transmission to the cell site;

iii. cell site signal divider means connected to said cell site duplexer output node for receiving the electrical signal from said cell site duplexer output node for coupling cell site channel signals in respective cell site channels to respective cell site signal channel output nodes;

iv. cell site signal combiner means connected to a plurality of cell site signal channel input nodes for receiving cell site channel signals in respective cell site channels and combining them to form a cell site composite signal and coupling it to said duplexer input node;

B. subscriber communications means for receiving signals from and transmitting signals into the selected region of the cell over the plurality of radio frequency channels, comprising;

i. subscriber antenna means for converting signals between electromagnetic signals from the subscriber and electrical signals;

ii. subscriber duplex means for receiving the electrical signals from the subscriber antenna means and directing them to a subscriber input node and for receiving amplified output signals to be transmitted into said selected region of said cell from a subscriber output node and for directing them to said antenna means for conversion to electromagnetic signals for transmission to the subscriber;

iii. subscriber signal divider means connected to said subscriber duplexer output node for receiving the electrical signal from said subscriber duplexer output node for coupling subscriber channel signals in respective subscriber channels to respective subscriber signal channel output nodes;

iv. subscriber signal combiner means connected to a plurality of subscriber signal channel input nodes for receiving subscriber channel signals in respective subscriber channels and combining them to form a subscriber composite signal and coupling it to said duplexer input node;

C. duplex amplification means including a plurality of duplex amplification module means for (i) receiving a channel signal from one of said cell site signal channel output nodes, amplifying it and coupling the amplified channel signal to the subscriber channel input node for transmission by said subscriber communications means to said subscriber, and (ii) for receiving a channel signal from one of said subscriber signal channel output nodes amplifying it and coupling the amplified channel signal to the cell site channel input node for transmission by said cell site communications means to said cell site; and

D. control means connected to one of said communications means and said duplex amplification means for controlling the operation of said duplex amplification means.

2. A cell enhancer as claimed in claim 1 further comprising amplification means connected between the output of said combining means and the input of each said duplexer means to amplify the signal coupled to the respective duplexer means.

3. A cell as claimed in claim 1 wherein each duplex amplification module means comprises:

A. frequency synthesizing means for generating signals of selected frequencies; and

B. up-link amplification means and down-link amplification means each connected to a respective output of a signal divider means and an input of a signal combining means including;

i. intermediate frequency signals generating means connected to said frequency synthesizing means and to the respective output of a signal divider means for generating an intermediate frequency signal in response to the signal from the connected signal divider means and from said frequency synthesizing means;

ii. intermediate signal amplification means connected to the output of said intermediate frequency signal generating means for amplifying said intermediate signal; and

iii. radio frequency signal generating means connected to the output of said intermediate signal amplification means, said frequency synthesizing means and a signal combining means for generating an output signal for transmission to the connected signal combining means in response to the signal from said intermediate signal amplification means and said frequency synthesizing means.

4. A cell enhancer as claimed in claim 3 wherein said up-link and down-link amplification means further comprise bandpass filter means connected to the output of said intermediate signal generating means and the input of said intermediate signal amplification means for performing a filtering operation on the intermediate frequency signal, said bandpass filter means having input buffer amplifier means for buffering the signal from said intermediate signal generating means before performing the filtering operation.

5. A cell enhancer as defined in claim 4 wherein said intermediate signal amplification means comprises a nonlinear amplifier.

6. A cell enhancer as defined in claim 3 wherein a duplex amplification module means further comprises switch means connected between the input of the down-link amplification means and the output of the respective signal divider means, said switch means having control input terminal, and switch control means connected to the output of the duplex amplification module means up-link amplification means for enabling said switch means to close to couple a signal from the signal divider means in response to a signal being present in the up-link amplification means, and otherwise being open.

7. A cell enhancer as defined in claim 6 wherein said controller means comprises:

A. coupler means for coupling radio frequency signals from and to one of said communications means;

B. receiving means connected to said coupler means for generating digital output signals in response to said radio frequency signals from said communications means;

C. micro-processor controlled circuit means for processing the digital output signals from said receiving means and for generating digital output signals for transmission to said cell site; and

D. transmitting means connected to said coupler means and said micro-processor controlled circuit means for receiving the digital output signals generated by said micro-processor controlled circuit means and for generating radio-frequency signals in response thereto for transmission to said coupler means.

8. A cell enhancer as claimed in claim 7 wherein said micro-processor controlled circuit means is connected to said frequency synthesizing means in each module means for controlling the frequencies of the signals generated by said frequency synthesizing means.

9. A cell enhancer as claimed in claim 8 further comprising signal generating means for generating a test signal having a selected frequency and a predetermined amplitude, detector means for detecting said test signal and in response thereto generating an amplitude value in response to the amplitude of the signal at the detector means, means responsive to said controller means for selectively connecting said generating means and detector means to selected ones of said amplification means, the amplitude value generated by said detector means being a function of the gain of the selected amplification means, said detector means being further connected to said controller means for transmitting said amplitude value to said controller means.

10. For use in a cellular radio telephone system, a cell enhancer for amplifying duplex communications between a cell site and a subscriber in a selected region of a cell over a plurality of radio frequency channels comprising:

A. cell site communications means for receiving signals from and transmitting signals to the cell site over the plurality of radio frequency channels, comprising;

i. cell site antenna means for converting signals between electromagnetic signals from the cell site or the subscriber and electrical signals;

ii. cell site duplex means for receiving the electrical signals from the antenna means and directing them to cell site input node and for receiving amplified output signals from a cell site output node for directing them to said antenna means for conversion to electromagnetic signals for transmission to the cell site;

B. subscriber communications means for receiving signals from and transmitting signals into the selected region of the cell over the plurality of radio frequency channels, comprising;

i. subscriber antenna means for converting signals between electromagnetic signals from the subscriber and electrical signals

ii. subscriber duplex means for receiving the electrical signals from the subscriber antenna means and directing them to a subscriber input node and for receiving amplified output signals to be transmitted into said selected region of said cell from a subscriber output node and for directing them to said antenna means for conversion to electromagnetic signals for transmission to the subscriber;

C. duplex amplification means comprising;

i. duplex input means connected to both said cell site input node and said subscriber input node for receiving input signals from both said cell site input node and said subscriber input node and generating in response thereto a combined input signal;

ii. duplex output means connected to said cell site output node and said subscriber output node for receiving a combined amplified output signal and generating in response thereto a cell site amplified output signal coupled to the respective cell site output node and a subscriber amplified output signal coupled to said subscriber output node; and

iii. wide band amplification means having an input connected to said duplex means and an output connected to said duplex output means for generating said combined amplified output signal in response to the combined input signal received from said duplex input means; and

D. control means connected to one of said communications means and said duplex amplification means for controlling the operation of said duplex amplification means.

11. A cell enhancer as defined in claim 11 wherein said wideband amplification means includes:

a. preamplification means having an input connected to receive signals from said duplex input means and an output for amplifying the signal from said duplex input means;

b. adjustable attenuation means connected to said preamplification means for attenuating the signal therefrom; and

c. power amplifier means connected to said attenuation means for amplifying the signal therefrom and coupling the amplified signal to the duplex output means.

12. A cell enhancer as defined in claim 12 wherein said controller means comprises:

A. coupler means for coupling radio frequency signals from and to one of said communications means;

B. receiving means connected to said coupler means for generating digital output signals in response to said radio frequency signals from said communications means;

C. micro-processor controlled circuit means for processing the digital output signals from said receiving means and for generating digital output signals for transmission to said cell site; and

D. transmitting means connected to said coupler means and said micro-processor controlled circuit means for receiving the digital output signals generated by said micro-processor controlled circuit means and for generating radio-frequency signals in response thereto for transmission to said coupler means.

13. A cell enhancer as claimed in claim 12 further comprising signal generating means for generating a test signal having a selected frequency and a predetermined amplitude, detector means for detecting said test signal and in response thereto generating an amplitude value in response to the amplitude of the signal at the detector means, means responsive to said controller means for selectively connecting said generating means and detector means to selected ones of said amplification means, the amplitude value generated by said detector means being a function of the gain of the selected amplification means, said detector means being further connected to said controller means for transmitting said amplitude value to said controller means.