Method and apparatus for processing power control signals in CDMA mobile telephone system

• US 6,097,972 A
• Filed: 08/29/1997
• Issued: 08/01/2000
• Est. Priority Date: 08/29/1997
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Tiedemann, Edward G. Jr., Saints, Keith W.
• Primary Examiner(s): Chin, Wellington
• Assistant Examiner(s): Woldetatios, Yemane
• Application Number:
  US08/919,806
• Time in Patent Office: 1,068 Days
• Field of Search: 455/127, 455/126, 455/132, 455/136, 455/137, 455/138, 455/232.1, 455/234.1, 455/246.1, 455/572, 455/226.2, 455/115, 455/296
• US Class Current: 455/572
• CPC Class Codes: H04W 52/42 in systems with time, space, frequency or polarisation diversity

Abstract

The transmitted power of a mobile telephone is established by power control bits that are transmitted in a traffic channel from a base station and that are demodulated by a rake receiver in the telephone. The rake receiver includes a plurality of demodulators that demodulate respective fingers of the traffic channel which may be caused by multipath conditions, with the power control bits from each demodulator being combined with the power control bits of the other demodulators in the rake receiver regardless of whether the demodulators are in lock with their respective fingers. The combined power control signal from a rake receiver associated with a first base station is then tested against a threshold. If the combined power is at least equal to the threshold, the combined power control signal is sent to a logic combiner. If other base stations are communicating with the mobile telephone, the combined power control signal from each of these other base stations is also sent to the logic combiner. If any power control signal commands the mobile telephone to decrease its transmitted power, it does so; otherwise, it increases its transmitted power. Alternatively, the power control bits from each demodulator in a rake receiver can be blocked if the finger energy falls below a threshold that depends on the number of fingers from the associated base station.

Claims

1. A mobile telephone for receiving signals from a base station, comprising:

a searcher;

a first demodulator controlled by the searcher for demodulating a first signal from the base station, the first signal propagating to the mobile telephone via a first path;

a second demodulator controlled by the searcher for demodulating a second signal from the base station, the second signal propagating to the mobile telephone via a second path;

a combiner for combining corresponding power control bits from the first and second signals regardless of whether the respective demodulator is in lock with the respective signal to thereby generate a first power command; and

a processor for passing the first power command when a comparison energy at least equals an energy threshold, and otherwise blocking the first power command.

2. The telephone of claim 1, further comprising a switch controlled by the processor for passing and blocking the first power command.

3. The telephone of claim 2, wherein the switch is a first switch, the signal is received from a second base station, and the telephone further comprises:

means for generating a second power command in response to the signal received from the second base station;

a second switch controlled by the processor for passing and blocking the second power command; and

a logic combiner for receiving the power commands and generating a power control signal in response thereto, the power control signal causing an increase or decrease in a transmitted power of the mobile telephone.

4. The telephone of claim 1, wherein the comparison energy is based on the energy of the first power command.

5. The telephone of claim 1, wherein the comparison energy is based on the energy of the first and second signals.

6. The telephone of claim 3, in combination with a mobile telephone system.

7. A mobile telephone for receiving a signal from a base station, comprising:

a searcher;

a rake receiver including a plurality of demodulators controlled by the searcher for demodulating respective signal fingers from the base station, each signal finger propagating to the mobile telephone via a respective path; and

a processor for passing a power control bit from a signal only when an energy associated with the signal at least equals an energy threshold, the energy threshold being established in response to the number of signals input to the rake receiver.

8. The telephone of claim 7, further comprising

a plurality of power control switches associated with respective demodulators and controlled by the processor for passing and blocking power control bits from the respective demodulators;

and

a combiner for combining corresponding power control bits from the switches to thereby generate first power commands.

9. The telephone of claim 8, wherein the base station is a first base station and the signal is received from a second base station, and the telephone further comprises:

means for generating a second power command in response to the signal received from the second base station; and

a logic combiner for receiving the power commands and generating a power control signal in response thereto, the power control signal causing an increase or decrease in a transmitted power of the mobile telephone.

10. The telephone of claim 9, in combination with a mobile telephone system.

11. A communication device, comprising:

a rake receiver including demodulators for demodulating a plurality of fingers of a signal from a base station, the signal including power control bits; and

a combiner for combining corresponding power control bits from the demodulators regardless of whether the demodulators are in lock with their respective fingers to thereby generate a first power command.

12. The device of claim 11, further comprising:

a processor for passing the first power command when a comparison energy at least equals an energy threshold, and otherwise blocking the first power command.

13. The device of claim 12, further comprising a switch controlled by the processor for passing and blocking the first power command.

14. The device of claim 13, wherein the switch is a first switch, the signal is received from a second base station, and the device further comprises:

means for generating a second power command in response to the signal received from the second base station;

a second switch controlled by the processor for passing and blocking the second power command; and

a logic combiner for receiving the power commands and generating a power control signal in response thereto, the power control signal causing an increase or decrease in a transmitted power of the device.

15. The device of claim 12, wherein the comparison energy is based on the energy of the first power command.

16. The device of claim 12, wherein the comparison energy is based on the energy of the fingers.

17. The device of claim 11, in combination with a mobile telephone system.

18. A method for establishing a transmitted power of a mobile telephone in a mobile telephone system having at least first and second base stations, each transmitting a common traffic signal to the mobile telephone, comprising the steps of:

demodulating a first finger of the traffic signal from the first base station, the first finger propagating to the mobile telephone via a first path;

demodulating a second finger of the traffic signal from the first base station, the second finger propagating to the mobile telephone via a second path;

combining corresponding power control bits from the first and second fingers regardless of the strengths of the fingers to thereby generate a first power command; and

passing the first power command when a comparison energy at least equals an energy threshold, and otherwise blocking the first power command.

19. The method of claim 18, further comprising the steps of:

generating a second power command in response to the traffic signal received from the second base station; and

generating a power control signal in response to the power commands, the power control signal causing an increase or decrease in the transmitted power of the mobile telephone.

20. The method of claim 18, comprising basing the comparison energy on the energy of the first power command.

21. The method of claim 18, comprising basing the comparison energy on the energy of the first and second fingers.

22. A method for establishing a transmitted power of a mobile telephone in a mobile telephone system having at least first and second base stations, each transmitting a common traffic signal to the mobile telephone, comprising the steps

demodulating respective signal fingers from the first base station, each signal finger propagating to the mobile telephone via a respective path;

and

passing a power control bit from a finger only when an energy associated with the finger at least equals an energy threshold, the energy threshold being established in response to the number of fingers.

23. The method of claim 22, further comprising the steps of:

combining corresponding power control bits from the fingers to thereby generate first power commands.

24. The method of claim 23, further comprising the steps of:

generating second power commands in response to signals received from the second base station; and

generating power control signals in response to the power commands, the power control signal causing an increase or decrease in the transmitted power of the mobile telephone.

25. In a mobile telephone in a mobile telephone system having at least first and second base stations, each base station transmitting a common traffic signal to the mobile telephone, a computer logic device comprising:

a computer logic storage device readable by a digital processing system; and

instructions embodied in the logic storage device, the instructions being executable by the digital processing system for performing method steps for establishing a transmitted power of the mobile telephone, the method steps comprising;

demodulating a first finger of the traffic signal from the first base station, the first finger propagating to the mobile telephone via a first path;

demodulating a second finger of the traffic signal from the first base station, the second finger propagating to the mobile telephone via a second path;

combining corresponding power control bits from the first and second fingers regardless of the strengths of the fingers to thereby generate a first power command; and

passing the first power command when a comparison energy at least equals an energy threshold, and otherwise blocking the first power command.

26. The computer logic device of claim 25, wherein the method steps further comprise:

generating a second power command in response to the traffic signal received from the second base station; and

generating a power control signal in response to the power commands, the power control signal causing an increase or decrease in the transmitted power of the mobile telephone.

27. The computer logic device of claim 26, wherein the method steps comprise basing the comparison energy on the energy of the first power command.

28. The computer logic device of claim 26, wherein the method steps comprise basing the comparison energy on the energy of the first and second fingers.

29. The computer logic device of claim 25, in combination with the mobile telephone.

30. The combination of claim 29, in further combination with a mobile telephone system.

31. In a mobile telephone in a mobile telephone system having at least first and second base stations, each base station transmitting a common traffic signal to the mobile telephone, a computer logic device comprising:

a computer logic storage device readable by a digital processing system; and

instructions embodied in the logic storage device, the instructions being executable by the digital processing system for performing method steps for establishing a transmitted power of the mobile telephone, the method steps comprising;

demodulating respective signal fingers from the first base station, each signal finger propagating to the mobile telephone via a respective path; and

passing a power control bit from a finger only when an energy associated with the finger at least equals an energy threshold, the energy threshold being established in response to the number of fingers.

32. The computer logic device of claim 31, wherein the method steps further comprise:

combining corresponding power control bits from the fingers to thereby generate first power commands.

33. The computer logic device of claim 32, wherein the method steps further comprise:

generating second power commands in response to signals received from the second base station; and

generating power control signals in response to the power commands, the power control signal causing an increase or decrease in the transmitted power of the mobile telephone.

34. The computer logic device of claim 31, in combination with the mobile telephone.

35. The combination of claim 34, in further combination with a mobile telephone system.