Adaptive power control in a mobile radio communications system

• US 6,334,047 B1
• Filed: 04/09/1999
• Issued: 12/25/2001
• Est. Priority Date: 04/09/1999
• Status: Expired due to Fees

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Ericson, Mårten, Andersson, Christoffer
• Primary Examiner(s): Bost, Dwayne
• Assistant Examiner(s): CONTEE, JOY KIMBERLY
• Application Number:
  US09/288,860
• Time in Patent Office: 991 Days
• Field of Search: 455/69, 455/126, 455/522, 455/442, 455/436, 455/437, 455/226.2, 455/226.3, 455/63, 455/67.3, 370/342, 370/311, 370/335, 370/331, 370/332
• US Class Current: 455/69
• CPC Class Codes: H04W 52/04 TPC
• CPC Class Codes: H04W 52/221 using past power control commands
• CPC Class Codes: H04W 52/362 Aspects of the step size

Abstract

An efficient and effective power control in a mobile communications system is provided that adapts to rapidly changing radio transmission conditions in varying and often unpredictable situations. The value of a signal parameter detected from a signal received by a radio transceiver is compared with a desired signal parameter value, and a difference is determined. A transmit power control command is sent to the radio transceiver and may instruct, for example, an increase or decrease in the level of radio transmit power. Included with the transmit power control command is a power control indicator indicating whether a first or a second type of power control adjustment should be used by the radio transceiver depending upon the determined difference. In one example embodiment, the power control indicator is a single-flag bit. A first value indicates that the first type of power control adjustment should be used; the second value indicates that the second type of power control adjustment should be used. In any event, the power control indicator itself does not include specific details of the first or second type of power control adjustment. Because only the indicator is sent (and not the details), signaling overhead and bandwidth consumption related to frequently sent power control commands are kept to a minimum. The specific details of the first and second power control adjustments are initially stored in to the radio transceiver. Such details may be updated when desirable, but the frequency of such updating is likely to be infrequent. Alternatively, a power control indicator may be communicated using techniques other than adding one or more flag bits to a fast transmit power control message to effect a change in power control type as long as signaling overhead is not significantly increased.

Claims

1. A method for controlling the transmit power of a radio transceiver, comprising:

detecting a parameter value of a signal received from the radio transceiver;

comparing the detected signal parameter value with a desired signal parameter value and determining a difference;

sending a transmit power control command to the radio transceiver; and

sending a power control indicator associated with the transmit power control command indicating whether a first or a second type of power control adjustment should be used by the radio transceiver depending on the difference.

2. The method in claim 1, wherein the power control indicator includes only a single flag bit.

3. The method in claim 1, wherein the power control indicator does not include the first or second type of power control adjustments.

4. The method in claim 1, wherein the method is implemented in a radio network node and the radio transceiver is a mobile station.

5. The method in claim 1, wherein the method is implemented in a mobile station and the radio transceiver is a base station.

6. The method in claim 1, wherein the signal parameter is a radio carrier-to-interference ratio (CIR).

7. The method in claim 1, wherein the transmit power control command instructs the radio transceiver to increase, decrease, or maintain transmit power.

8. The method in claim 1, wherein the first and second types of power control adjustment determine an amount by which the radio transceiver adjusts its transmit power.

9. The method in claim 8, wherein the first type of power control adjustment is a first amount to be used under a first type of transmission condition, and wherein the second type of power control adjustment is a second amount to be used under a second type of transmission condition.

10. The method in claim 9, wherein the first amount is a default amount and the second amount is larger or smaller than the default amount depending on the transmission condition.

11. The method in claim 1, further comprising:

providing the radio transceiver at a first frequency, the first and second power control adjustments,

wherein the transmit power control commands are sent at a second frequency greater than the first frequency.

12. The method in claim 1, wherein transmit power control commands instruct the radio transceiver to increase or to decrease transmit power, and the power control indicator is a flag bit which at a first value indicates a first amount to increase or decrease transmit power and at a second value indicates a second amount to increase or decrease transmit power.

13. The method in claim 1, wherein the first and second type of power control adjustments include a first and second power control scheme, respectively.

14. The method in claim 1, wherein the power control indicator corresponds to one of different patterns of the transmit power control command.

15. The method in claim 1, wherein the power control indicator is included with the transmit power control command.

16. The method in claim 1, wherein the power control indicator is included with a control message other than the transmit power control command frequently sent to the radio transceiver.

17. The method in claim 1, wherein the sending of the power control indicator is performed with minimal increase in signaling overhead.

18. A method for controlling the transmit power of a mobile station transmitting to a radio network, comprising:

detecting at a first frequency a signal-to-interference parameter value of a signal received from the mobile radio;

comparing the detected signal-to-interference parameter value with a desired signal-to-interference parameter value and determining a difference;

comparing the difference with a threshold;

sending a transmit power control command to the mobile station to possibly increase or decrease its transmit power depending on the difference; and

associating with the transmit power control command a power control indicator indicating that a first type of power control adjustment should be used by the mobile station if the difference is less than the threshold and that a second type of power control adjustment should be used by the mobile station if the difference is greater than or equal to the threshold.

19. The method in claim 18, further comprising:

providing to the mobile station at a second frequency less than the first frequency the first and second types of power control adjustments.

20. The method in claim 18, wherein transmit power control commands and the power control indicator are sent over a slotted channel, and the first frequency corresponds to a time slot frequency.

21. The method in claim 18, wherein the first and second types of adjustments include first and second power adjustment control procedures.

22. The method in claim 18, wherein the first and second types of adjustments include first and second power adjustment step sizes.

23. The method in claim 18, wherein the difference is compared to plural thresholds, each threshold having a corresponding type of power control adjustment.

24. The method in claim 18, wherein the power control indicator includes only a single flag bit.

25. The method in claim 18, wherein the power control indicator does not include the first or second type of power control adjustments.

26. A mobile transceiver capable of communicating with a radio network, comprising:

a transceiver including a radio transmitter and a radio receiver; and

a controller having first and second types of power control adjustments and receiving from the radio network transmit power control commands to increase or decrease a transmit power level of the transmitter and a power control indicator indicating whether the first or second type of power control adjustment should be employed,

wherein the controller is configured to adjust the transmit power level of the transmitter using one of the first and second types of power control adjustments depending on a value of the power control indicator.

27. The mobile transceiver in claim 26, wherein the received power control indicator is associated with one of the transmit power control commands.

28. The mobile transceiver in claim 26, wherein the power control indicator includes only a single flag bit.

29. The mobile transceiver in claim 26, wherein the power control indicator does not include the first or second type of power control adjustments.

30. The mobile transceiver in claim 26, wherein transmit power control commands and the power control indicator are sent over a slotted channel, and the transmit power control commands are sent at a time slot frequency.

31. The mobile transceiver in claim 26, wherein the first and second types of adjustments include first and second power adjustment control procedures.

32. The mobile transceiver in claim 26, wherein the first and second types of adjustments include first and second power adjustment step sizes.

33. A radio network node sending power control commands to a radio transceiver, comprising:

a detector for detecting a signal parameter value of a signal received from the radio transceiver;

a comparator for comparing the detected signal parameter value with a desired signal parameter value and determining a difference; and

a transmitter for transmitting a transmit power control command to the radio transceiver and a power control indicator indicating whether a first or a second type of power control adjustment should be used by the radio transceiver depending on the difference.

34. The radio network node in claim 33, wherein the radio network node includes a base station.

35. The radio network node in claim 33, wherein the radio network node includes a radio network controller.

36. The radio network node in claim 33, wherein the a power control indicator corresponds to a flag bit and does not include the first or second type of power control adjustments.

37. The radio network node in claim 33, wherein the signal parameter is a carrier-to-interference ratio (CIR).

38. The radio network node in claim 33, wherein the transmit power control command instructs the radio transceiver to increase or decrease transmit power, and wherein the first and second types of power control adjustment determine an amount by which the radio transceiver adjusts its transmit power.

39. The radio network node in claim 33, wherein the first type of power control adjustment is a first amount to be used under a first type of transmission condition, and wherein the second type of power control adjustment is a second amount to be used under a second type of transmission condition.

40. The radio network node in claim 33, further comprising:

means for providing the radio transceiver at a first frequency, the first and second power control adjustments,

wherein the transmitter transmits the transmit power control commands at a second frequency greater than the first frequency.

41. The radio network node in claim 33, wherein the power control indicator corresponds to one of different patterns of the transmit power control command.

42. The radio network node in claim 33, wherein the power control indicator is included with the transmit power control command.

43. The radio network node in claim 33, wherein the power control indicator is included with a control message other than the transmit power control command frequently sent to the radio transceiver.

44. The radio network node in claim 33, wherein the sending of the power control indicator is performed with minimal increase in signaling overhead.