Power management for a telephone system by dynamically adjusting transmission power

• US 6,256,476 B1
• Filed: 06/25/1998
• Issued: 07/03/2001
• Est. Priority Date: 06/25/1998
• Status: Expired due to Term

• Current Assignee: Skyworks Solutions Incorporated
• Original Assignee: Conexant Systems Incorporated (Synaptics Incorporated)
• Inventors: Beamish, Norman J., Walley, John S.
• Primary Examiner(s): Bost, Dwayne
• Assistant Examiner(s): GELIN, JEAN ALLAND
• Application Number:
  US09/104,732
• Time in Patent Office: 1,104 Days
• Field of Search: 455/522, 455/571, 455/572, 455/573, 455/574, 455/575, 455/69, 455/38.3, 455/343, 455/68, 370/252, 370/311, 370/349
• US Class Current: 340/7.36
• CPC Class Codes: H04W 52/08 Closed loop power control
• CPC Class Codes: H04W 52/283 Power depending on the position of the mobile
• CPC Class Codes: H04W 52/362 Aspects of the step size
• CPC Class Codes: H04W 52/367 Power values between minimum and maximum limits, e.g. dynamic range
• CPC Class Codes: H04W 52/54 Signalisation aspects of the TPC commands, e.g. frame structure
• CPC Class Codes: H04W 52/56 Detection of errors of TPC bits

Abstract

A power management system for a mobile unit wherein the base station detects the quality of the signals transmitted by the mobile unit. Based on this signal quality, the base station determines if the mobile unit should increase the transmission power level. If an increase in transmission power is indicated, the base station sends a signal to the mobile unit to cause the mobile unit to increase transmission power. However, to save battery power, the mobile unit only transmits at the increased power level for a limited amount of time, and then automatically returns to transmitting at the lower power level. Further, a slightly decreased high power level is established to allow the mobile unit to function when it is located away from the base station, yet not near the outer transmission boundary.

Claims

1. A wireless communication system comprising:

a base station which transmits a first plurality of signals and receives a second plurality of signals;

a signal strength detector in the base station which determines the quality of at least some of said second plurality of signals received by the base station, wherein when the quality is below a predetermined threshold, the base station inserts a low power indicator in at least one of said first plurality of signals transmitted by the base station; and

a mobile unit which receives the first plurality of signals transmitted by the base station, the mobile unit configured to operate at a first power level or a second power level, the first power level being higher than the second power level, wherein when the mobile unit receives the low power indicator from the base station, the mobile unit operates at the first power level and after the transmission of a signal, the mobile unit automatically resets to operate at the second power level.

2. The wireless communication system of claim 1, wherein a processor causes the mobile unit to transmit at the second power level unless the low power indicator is present.

3. The wireless communication system of claim 1, wherein the signal strength detector measures the RSSI.

4. The wireless communication system of claim 1, wherein the signal strength detector measures the estimated frame-by-frame bit error rate.

5. The wireless communication system of claim 1, wherein the signal strength detector is based upon a parity check.

6. A wireless communication unit comprising:

a receiver which is configured to receive a first plurality of signals, at least one of said first plurality of signals having a power level command;

a transmitter which is configured to transmit a second plurality of signals over at least two power levels, wherein a first power level is greater than a second power level; and

a processor connected to the receiver and the transmitter, the processor configured to control the transmitter so as to vary the power levels of the second plurality of signals, the processor further configured to select the first power level in response to the power level command and then to automatically select the second power level after the transmission of the second plurality of signals.

7. The wireless communication system of claim 6, wherein the first plurality of signals comprises a frame of data.

8. The wireless communication system of claim 6, wherein the predetermined time duration expires after each frame of data.

9. A method of conserving power in a wireless communication system comprising the acts of:

determining the quality of a first signal received from the mobile unit;

comparing the received signal quality to a predetermined value;

transmitting a second signal from the mobile unit at a first power level when the received signal quality is below the predetermined value; and

automatically resetting the mobile unit to transmit at a second power level following a transmission at a first power level, the first power level being higher than the second power level.

10. The method of claim 9, wherein the quality of signals transmitted is determined by the RX Quality.

11. The method of claim 9, wherein the quality of signals transmitted is determined by the estimated frame-by-frame bit error rate.

12. The method of claim 9, wherein the quality of signals transmitted is determined by a parity check.

13. The method of claim 9, further comprising the acts of:

setting an indicator when the received signal quality is below the predetermined value; and

transmitting a third signal having the indicator to the mobile unit.

14. The method of claim 13, wherein the indicator is set by a base station.

15. A wireless communication system comprising;

a signal strength indicator which determines the quality of a signal received from a mobile unit; and

a power level adjustor which increases the power level of a signal transmitted by the mobile unit for only a predetermined number of transmissions when the signal quality is below a set value.

16. The wireless communication system of claim 15, wherein the predetermined number of transmissions is one.

17. The wireless communication system of claim 15, wherein the signal quality is obtained from the RX Level.

18. The wireless communication system of claim 15, wherein the signal received from the mobile unit comprises a frame of data.

19. The wireless communication system of claim 18, wherein the power level adjustor resets to a lower power level after each frame of data.

20. A method of saving power in a communications system which provides for the repeated exchange of signals between a first location and a second location, the method comprising the acts of:

determining the quality of a first signal transmitted by the first location;

transmitting information instructing the first location to increase the transmission power for a second signal to a first power level if the quality of the first signal falls below a predetermined level;

automatically resetting the transmission power of the first location to a second power level after transmission of the second signal, the first power level being higher than the second power level;

determining the quality of the second signal transmitted by the first location; and

transmitting information instructing the first location to increase the transmission power for a third signal to a first power level if the quality of the second signal falls below a predetermined level.

21. The method of claim 20, wherein the first location transmits signals at the second power level when the quality of the signals received at the second location exceeds the predetermined level.

22. The method of claim 20, wherein the power level instruction information is transmitted by the second location.

23. A wireless communication system comprising;

means for determining the quality of a signal received;

means for indicating when the quality of the signal falls below a threshold; and

means for increasing the signal transmission power for only a predetermined number of transmissions when the indication means is detected so that the transmission power is automatically reset.