Power control for wireless communications system

• US 6,370,203 B1
• Filed: 11/04/1998
• Issued: 04/09/2002
• Est. Priority Date: 11/04/1998
• Status: Expired due to Fees

• Current Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Original Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Inventors: Boesch, Ronald D., Doherty, Peter J.
• Primary Examiner(s): Pham, Chi
• Assistant Examiner(s): Nguyen, Dung X.
• Application Number:
  US09/186,493
• Time in Patent Office: 1,252 Days
• Field of Search: 375/135, 375/136, 375/140, 375/146, 375/147, 375/295, 375/298, 375/308, 375/312, 375/297, 455/75, 455/522, 455/69, 455/70, 455/115, 370/342, 370/252
• US Class Current: 375/297
• CPC Class Codes: H03G 3/3052 in bandpass amplifiers (H.F. or I.F.) or in frequency-changers used in a (super)heterodyne receiver H03G3/32, H03G3/34 take precedence
• CPC Class Codes: H04W 52/08 Closed loop power control
• CPC Class Codes: H04W 52/10 Open loop power control
• CPC Class Codes: H04W 52/52 using AGC [Automatic Gain Control] circuits or amplifiers

Abstract

Power control circuitry for the transmitting section of a mobile terminal provides gain control for amplifiers operating at different frequencies. Preferably, one amplifier controls the signal gain the signal transmission path in the IF section and another amplifier controls gain in the signal transmission path in the radio frequency (RF) section. One variable gain amplifier may be controlled based on the strength of the received signals while the other may be controlled based on commands from the base station and/or calibration and alignment settings during manufacturing. In addition, one or both of the amplifiers may optionally be controlled in whole or in part based on calibration and/or alignment settings established during manufacturing. Preferably, the gain control signal based on received signal strength is analog based and the control signal received from the control system is a pure digital signal substantially immune to noise. In such an embodiment, the corresponding amplifier is configured to receive a digital value and provide a corresponding amplifier gain.

Claims

1. In a wireless communications system in which users communicate using spread spectrum communications via a mobile terminals and at least one base station, a transmission power control circuit for controlling transmission signal power for a mobile terminal, wherein each mobile terminal includes an antenna and a receiver, said power control circuit comprising:

a. a signal path in the mobile terminal amplifying a signal to be transmitted, said path having a first portion for said signal gain controlled at a first frequency and a second portion for said signal further gain controlled at a second frequency;

b. a first variable gain amplifier for amplifying signals operating about the first frequency in said first portion of said signal path, said first variable gain amplifier having a gain control input and adapted to provide amplification gain proportional to a first control signal received at the gain control input;

c. a second variable gain amplifier for amplifying signals operating about the second frequency in said second portion of said signal path, said second variable gain amplifier having a gain control input and adapted to provide amplification gain proportional to a second control signal received at the gain control input; and

d. one of said first or second control signals being responsive to relative power levels of signals received by the mobile terminal'"'"'s receiver and the other of said first or second control signals responsive to power level commands.

2. The mobile terminal power control circuit of claim 1 wherein said circuit includes a mixer in said signal path between said first and second variable gain amplifiers, said mixer configured to alter the frequency of said signals in said signal path from the first frequency to the second frequency.

3. The mobile terminal power control circuit of claim 1 wherein the first frequency is an intermediate frequency used for spread spectrum communications.

4. The mobile terminal power control circuit of claim 1 wherein the second frequency is a radio frequency.

5. The mobile terminal power control circuit of claim 1 wherein the first frequency is an intermediate frequency used for spread spectrum communications and the second frequency is a radio frequency for final transmission.

6. The mobile terminal power control circuit of claim 1 wherein said first variable gain amplifier, receives said control signal responsive to power level commands and said second variable gain amplifier receives said control signal responsive to relative power levels of signals received by the mobile terminal'"'"'s receiver.

7. The mobile terminal power control circuit of claim 1 wherein said first and second portions of said signal path and said first and second variable gain amplifiers are integrated into a single integrated circuit chip.

8. The mobile terminal power control circuit of claim 2 wherein said first and second portions of said signal path, said first and second variable gain amplifiers, and said mixer are integrated into a single integrated circuit chip.

9. The mobile terminal power control circuit of claim 1 wherein said first variable gain amplifier is a analog controlled variable gain amplifier and said second variable gain amplifier is an digital controlled variable gain amplifier, said first variable gain amplifier adapted to provide a gain proportional to the power level commands received by the terminal, and said second variable gain amplifier adapted to provide a gain proportional to relative power levels of signals received by the mobile terminal'"'"'s receiver.

10. The mobile terminal power control circuit of claim 1 wherein said first variable gain amplifier is a digitally controlled variable gain amplifier and said second variable gain amplifier is an analog controlled variable gain amplifier, said first variable gain amplifier adapted to provide a gain proportional to the power level commands received by the terminal, and said second variable gain amplifier adapted to provide a gain proportional to relative power levels of signals received by the mobile terminal'"'"'s receiver.

11. The mobile terminal power control circuit of claim 1 wherein the power level commands are based on power control signals originating from the base station.

12. The mobile terminal power control circuit of claim 1 wherein the control signal to said first variable gain amplifier depends at least in part upon calibration or factory alignment information.

13. The mobile terminal power control circuit of claim 1 wherein the mobile terminal includes processing circuitry providing the control signals corresponding to power level commands, said second variable gain amplifier receiving control signals based on said control signals from said processing circuitry.

14. The circuit of claim 1 wherein the gains for said variable gain amplifiers are allocated to provide an overall variable gain having a range adequate for mobile operation and the gain for said variable gain amplifier corresponding to power level commands is variable over a range allowing for calibration of the mobile device to compensate for component variation in manufacturing.

15. A power amplification circuit in a mobile communications device comprising:

a power amplification signal path in a mobile communications device for amplifying a mobile communication signal to be transmitted;

a digital controlled variable gain amplifier in said signal path;

an analog controlled variable gain amplifier in said signal path;

said digital controlled variable gain amplifier having a digital gain control input and adapted to provide a gain proportional to a digital value received at the digital gain control input;

said analog controlled variable gain amplifier having an analog gain control input and adapted to provide a gain proportional to an analog signal received at the analog gain control input; and

wherein the gains for said digital and analog controlled variable gain amplifiers are proportioned to provide an overall variable gain having a range of approximately 85 dB so as to be adequate for mobile operation and said digital controlled variable gain amplifier'"'"'s gain is variable over a range of approximately 20 dB allowing for calibration of the mobile device to compensate for component variation in manufacturing.

16. A power amplification circuit in a mobile communications device comprising:

a power amplification signal path in a mobile communications device for amplifying a mobile communication signal to be transmitted;

a digital controlled variable gain amplifier in said signal path;

an analog controlled variable gain amplifier in said signal path;

said digital controlled variable gain amplifier having a digital gain control input and adapted to provide a gain proportional to a digital value received at the digital gain control input;

said analog controlled variable gain amplifier having an analog gain control input and adapted to provide a gain proportional to an analog signal received at the analog gain control input; and

wherein said circuit includes a mixer in said signal path between said first and second variable gain amplifiers, said mixer configured to alter the frequency of said signals in said signal path from a first frequency to a second frequency.

17. The mobile terminal power control circuit of claim 16 wherein the first frequency is an intermediate frequency used for spread spectrum communications.

18. The mobile terminal power control circuit of claim 17 wherein the second frequency is a radio frequency for final signal transmission.

19. The mobile terminal power control circuit of claim 18 wherein the digital controlled variable gain amplifier operates about the first frequency and the analog controlled variable gain control amplifier operates about the second frequency.

20. The mobile terminal power control circuit of claim 18 wherein the analog controlled variable gain amplifier operates about the first frequency and the digital controlled variable gain control amplifier operates about the second frequency.

21. A power amplification circuit in a mobile communications device comprising:

a power amplification signal path in a mobile communications device for amplifying a mobile communication signal to be transmitted;

a digital controlled variable gain amplifier in said signal path;

an analog controlled variable gain amplifier in said signal path;

said digital controlled variable gain amplifier having a digital gain control input and adapted to provide a gain proportional to a digital value received at the digital gain control input;

said analog controlled variable gain amplifier having an analog gain control input and adapted to provide a gain proportional to an analog signal received at the analog gain control input; and

wherein said digital controlled variable gain amplifier is adapted to receive gain control signals responsive to relative power levels of signals received by the mobile terminal'"'"'s receiver.

22. A power amplification circuit in a mobile communications device comprising:

a power amplification signal path in a mobile communications device for amplifying a mobile communication signal to be transmitted;

a digital controlled variable gain amplifier in said signal path;

an analog controlled variable gain amplifier in said signal path;

said digital controlled variable gain amplifier having a digital gain control input and adapted to provide a gain proportional to a digital value received at the digital gain control input;

said analog controlled variable gain amplifier having an analog gain control input and adapted to provide a gain proportional to an analog signal received at the analog gain control input; and

wherein said analog controlled variable gain amplifier is adapted to receive gain control signals corresponding to power level commands.

23. In a wireless communications system in which users communicate using spread spectrum communications via a mobile terminal and at least one base station, a transmission power control method for controlling transmission signal power for a mobile terminal, wherein each mobile terminal includes an antenna and a receiver, said method comprising:

a. providing a signal path in a mobile communication device for amplifying a signal to be transmitted, said path having a first portion for the signal gain controlled at an intermediate frequency and a second portion for the signal further gain controlled at a final radio transmission frequency;

b. amplifying signals operating about the intermediate frequency in said first portion of said signal path in response to power level commands; and

c. amplifying signals operating about the final radio transmission frequency in said second portion of said signal path in proportional response to relative power levels of signals received by the mobile terminal'"'"'s receiver.

24. An integrated circuit providing for transmission power level control in a wireless communications system mobile terminal, said integrated circuit comprising:

a. an integrated circuit package;

b. a signal path in said package for amplifying a signal to be transmitted, said path having a first portion for the signal gain controlled at a first frequency and a second portion for the signal further gain controlled at a second frequency;

c. a first variable gain amplifier for amplifying signals operating about the first frequency in said first portion of said signal path, said first variable gain amplifier having a gain control input and adapted to provide amplification gain proportional to a first control signal received at the gain control input;

d. a second variable gain amplifier for amplifying signals operating about the second frequency in said second portion of said signal path, said first variable gain amplifier having a gain control input and adapted to provide amplification gain proportional to a second control signal received at the gain control input; and

e. one of said first or second control signals being proportional to relative power levels of signals received by the mobile terminal'"'"'s receiver and the other of said first or second control signals corresponding to power level commands.

25. The integrated circuit of claim 24 further including a mixer in said signal path between said first and second variable gain amplifiers, said mixer configured to alter the frequency of said signals in said signal path from the first frequency to the second frequency.

26. The integrated circuit of claim 24 wherein the first frequency is an intermediate frequency used for spread spectrum communications and the second frequency is a radio frequency for final transmission.

27. The integrated circuit of claim 24 wherein said first variable gain amplifier receives said control signal corresponding to power level commands and said second variable gain amplifier receives said control signal proportional to relative power levels of signals received by the mobile terminal'"'"'s receiver.

28. The integrated circuit of claim 24 wherein said first variable gain amplifier is a analog controlled variable gain amplifier and said second variable gain amplifier is an digital controlled variable gain amplifier, said first variable gain amplifier adapted to provide a gain proportional to the power level commands received by the terminal, and said second variable gain amplifier adapted to provide a gain proportional to relative power levels of signals received by the mobile terminal'"'"'s receiver.

29. The integrated circuit of claim 24 wherein said first variable gain amplifier is a digitally controlled variable gain amplifier and said second variable gain amplifier is an analog controlled variable gain amplifier, said first variable gain amplifier adapted to provide a gain proportional to the power level commands received by the terminal, and said second variable gain amplifier adapted to provide a gain proportional to relative power levels of signals received by the mobile terminal'"'"'s receiver.

30. In a wireless communications system in which users communicate using spread spectrum communications via a mobile terminals and at least one base station, a transmission power control circuit for controlling transmission signal power for a mobile terminal, wherein each mobile terminal includes an antenna and a receiver, said power control circuit comprising:

a. a signal path in the mobile terminal amplifying a signal to be transmitted, said path having a first portion for said signal gain controlled at a first frequency and a second portion for said signal further gain controlled at a second frequency;

b. a first variable gain amplifier for amplifying signals operating about the first frequency in said first portion of said signal path, said first variable gain amplifier having a gain control input and adapted to provide amplification gain proportional to a first control signal received at the gain control input;

c. a second variable gain amplifier for amplifying signals operating about the second frequency in said second portion of said signal path, said second variable gain amplifier having a gain control input and adapted to provide amplification gain proportional to a second control signal received at the gain control input;

d. an auxiliary input for inputting calibration type information; and

e. one of said first or second control signals being responsive to relative power levels of signals received by the mobile terminal'"'"'s receiver and the other of said first or second control signals corresponding to said calibration type information.

31. The mobile terminal power control circuit of claim 30 wherein said control signal responsive to relative power levels of signals received by the mobile terminal'"'"'s receiver is further responsive to power level commands.

32. The mobile terminal power control circuit of claim 30 wherein the first frequency is an intermediate frequency used for spread spectrum communications and the second frequency is a radio frequency for final transmission.

33. The mobile terminal power control circuit of claim 30 wherein said first variable gain amplifier receives said control signal responsive to power level commands and said second variable gain amplifier receives said control signal corresponding to said calibration type information.

34. The mobile terminal power control circuit of claim 30 wherein said first and second portions of said signal path and said first and second variable gain amplifiers are integrated into a single integrated circuit chip.

35. The mobile terminal power control circuit of claim 30 wherein said first variable gain amplifier is a analog controlled variable gain amplifier and said second variable gain amplifier is an digital controlled variable gain amplifier, said first variable gain amplifier adapted to provide a gain proportional to the power level commands received by the terminal, and said second variable gain amplifier adapted to provide a gain corresponding to said calibration type information.

36. The mobile terminal power control circuit of claim 30 wherein said first variable gain amplifier is a digitally controlled variable gain amplifier and said second variable gain amplifier is an analog controlled variable gain amplifier, said first variable gain amplifier adapted to provide a gain proportional to the power level commands received by the terminal, and said second variable gain amplifier adapted to provide a gain corresponding to said calibration type information.

37. The mobile terminal power control circuit of claim 31 wherein the power level commands are based on power control signals originating from the base station.

38. In a wireless communications system in which users communicate using spread spectrum communications via a mobile terminal and at least one base station, a transmission power control method for controlling transmission signal power for a mobile terminal, wherein each mobile terminal includes an antenna and a receiver, said method comprising:

a. providing calibration type information;

b. providing a signal path in a mobile communication device for amplifying a signal to be transmitted, said path having a first portion for the signal gain controlled at a first frequency and a second portion for the signal further gain controlled at a second frequency;

c. amplifying signals operating about the first frequency in said first portion of said signal path at a first variable gain amplifier in response to power level commands and in response to relative power levels of signals received by the mobile terminal'"'"'s receiver; and

d. amplifying signals operating about the second frequency in said second portion of said signal path at a second variable gain amplifier according to said calibration type information.

39. The method of claim 38 wherein said first frequency is an intermediate frequency and wherein said second frequency is a final radio transmission frequency.

40. The method of claim 38 wherein said second frequency is an intermediate frequency and wherein said first frequency is a final radio transmission frequency.

41. The method of claim 38 wherein said first portion of said signal path is upstream from said second portion of said signal path.