Reverse link, closed loop power control in a code division multiple access system

• US 5,812,938 A
• Filed: 09/19/1996
• Issued: 09/22/1998
• Est. Priority Date: 07/11/1994
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Wheatley, Charles E. III, Gilhousen, Klein S., Levin, Jeffrey A.
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): To, Doris
• Application Number:
  US08/719,296
• Time in Patent Office: 733 Days
• Field of Search: 455/69, 455/70, 455/127, 455/114-115, 455/33.1, 455/422, 455/522, 455/561, 455/517, 455/524, 455/343, 455/226.1, 455/226.2, 455/226.3, 455/100, 455/574 , 455/67.1, 455/117, 370/318, 370/310, 370/320, 375/200, 375/205
• US Class Current: 455/69
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 28/22 Negotiating communication rate
• CPC Class Codes: H04W 52/08 Closed loop power control
• CPC Class Codes: H04W 52/12 Outer and inner loops
• CPC Class Codes: H04W 52/267 taking into account the information rate
• CPC Class Codes: H04W 74/00 Wireless channel access

Abstract

The process of the present invention enables a mobile radiotelephone to operate at a 100% duty cycle while providing closed loop power control. The base station measures the signal to noise ratio of the signal from the mobile and compares that SNR with the SNR threshold values the base station has for each data rate the mobile is capable of transmitting. The base station then generates power control commands to instruct the mobile to change its power depending on the outcome of the comparisons.

Claims

1. At a base station, a method for controlling transmitter power of a remote communication device which transmits a signal at a predetermined data rate of a plurality of data rates, each data rate having a different power level, the method comprising the steps of:

receiving said signal;

determining a quality level of said received signal;

comparing said quality level to each of a plurality of quality thresholds which each correspond to a respective power level of said plurality of data rates;

generating a power control signal in response to said comparing step, said power control signal comprising a plurality of power control commands, each of said power control commands corresponding to one of said plurality of data rates; and

transmitting said power control signal to said remote communication device.

2. The method of claim 1 wherein said plurality of data rates comprises N data rates and said power control signal comprises N power control commands, each of said power control commands corresponding to a different one of said plurality of data rates.

3. The method of claim 1 wherein said plurality of data rates comprises N data rates and said power control signal comprises N-1 power control commands, a first power control command of said N-1 power control commands corresponding to said comparing of said quality level to a maximum quality threshold of said plurality of quality thresholds and a remaining group of power control commands of said N-1 power control commands corresponding to said comparing of said quality level to each of a remaining group of quality thresholds of said plurality of quality thresholds.

4. The method of claim 1 wherein said power control signal comprises a plurality of power control groups, each power control group comprising:

a first power control bit corresponding to said comparing of said quality level to a first quality threshold of said plurality of quality thresholds; and

a second power control bit corresponding, in a first power control group of said plurality of power control groups, to said comparing of said quality level to a second quality threshold of said plurality of quality thresholds, and corresponding, in a second power control group of said plurality of power control groups, to said comparing of said quality level to a third quality threshold of said plurality of quality thresholds.

5. The method of claim 1 wherein said power control signal comprises a sequence of power control bits, with every other one of said power control bits corresponding to said comparing of said quality level to a first quality threshold of said plurality of quality thresholds, and a remaining set of power control bits of said sequence of power control bits alternating in corresponding sequence to said comparing of said quality level to a different one of said plurality of quality thresholds.

6. In a remote communication device having a transmitter which transmits a signal at a predetermined data rate of a plurality of data rates, each of said plurality of data rates having a different power level, said remote communication device communicating with a base station, a method for adjusting transmitter power of said remote communication device, said method comprising the steps of:

transmitting a signal to said base station at a predetermined data rate of the plurality of data rates, said signal having a power level corresponding to said predetermined data rate;

receiving a power control signal corresponding to said plurality of data rates, said power control signal comprising a plurality of power control commands, each of said power control commands corresponding to one of said plurality of data rates; and

adjusting said transmitter power in response to said power control signal and said predetermined data rate.

7. The method of claim 6 wherein said plurality of data rates comprises N data rates and said power control signal comprises N power control commands, each of said power control commands corresponding to a different one of said plurality of data rates.

8. The method of claim 6 wherein said plurality of data rates comprises N data rates and said power control signal comprises N-1 power control commands, a first power control command of said N-1 power control commands corresponding to a maximum data rate of said plurality of data rates and a remaining group of power control commands of said N-1 power control commands corresponding to each of a remaining group of data rates of said plurality of data rates.

9. The method of claim 6 wherein said power control signal comprises a plurality of power control groups, each power control group comprising:

a first power control bit corresponding, in each power control group of said plurality of power control groups, to a first data rate of said plurality of data rates; and

a second power control bit corresponding, in a first power control group of said plurality of power control groups, to a second data rate of said plurality of data rates, and corresponding, in a second power control group of said plurality of power control groups, to a third data rate of said plurality of data rates.

10. The method of claim 6 wherein said power control signal comprises a sequence of power control bits, every other power control bit of said sequence of power control bits corresponding to a first data rate of said plurality of data rates, and a remaining set of power control bits of said sequence of power control bits correspondingly alternating in sequence to a different one of said plurality of data rates.