Method, device and system for power control step size selection based on received signal quality

• US 6,760,598 B1
• Filed: 05/01/2002
• Issued: 07/06/2004
• Est. Priority Date: 05/01/2002
• Status: Active Grant

• Current Assignee: Nokia Solutions and Networks US LLC (Nokia Corporation)
• Original Assignee: Nokia Corporation
• Inventors: Kurjenniemi, Janne
• Primary Examiner(s): APPIAH, CHARLES NANA
• Application Number:
  US10/138,025
• Time in Patent Office: 797 Days
• Field of Search: 455/522, 455/127.1, 455/69, 455/70, 370/252, 370/318, 370/320, 370/335
• US Class Current: 455/522
• CPC Class Codes: H04W 52/04 TPC
• CPC Class Codes: H04W 52/14 Separate analysis of uplink or downlink
• CPC Class Codes: H04W 52/221 using past power control commands
• CPC Class Codes: H04W 52/34 TPC management, i.e. sharing limited amount of power among users or channels or data types, e.g. cell loading
• CPC Class Codes: H04W 52/362 Aspects of the step size
• CPC Class Codes: H04W 52/56 Detection of errors of TPC bits

Abstract

A method, device and system, for determining downlink transmission power step size for both UP and DOWN transmission power control commands (TPC). The method, device and system use reception quality and a plurality of thresholds to determine these step sizes. Provision is made for determining step size and the TPC command values when the TPC command is evaluated to be erroneous and when reception quality is less than a minimum threshold value.

Claims

1. A method to select the step size for increasing (StepU) the transmission power and the step size for decreasing (StepD) the transmission power of a transmitter based upon the reception quality of a received signal, comprising the steps of:

1) determining the reception quality of a received signal; and

2) for each integer i, where i ranges from one to N, where N is an integer greater than one, comparing the reception quality to a threshold_i, and if the reception quality is greater than threshold_i, selecting step size StepU_i for increasing the transmission power and step size StepD_i for decreasing the transmission power and then terminating all further comparisons of reception quality to lower thresholds, if i<

N;

where thresholds_{i, i+1, . . . , N} decrease monotonically.

2. A method as claimed in claim 1, where step size StepU_i≧

StepU_i+1 for all i.

3. A method as claimed in claim 2, where step size StepD_i≧

StepD_i+1 for all i.

4. A method as claimed in claim 1, where step size StepD_i≧

StepD_i+1 for all i.

5. A method as claimed in claim 3, further including the step of determining the value of a transmission power control command (TPC).

6. A method as claimed in claim 5, wherein if the value of the TPC command is indicative of an erroneous TPC command, then setting the step size for increasing transmission power (StepU) to a predetermined value and skipping all comparisons between received signal quality and said thresholds (threshold_{i,i+1, . . . N}), and if the value of the TPC command is not indicative of an erroneous TPC command, performing step 2.

7. A method as claimed in claim 6, wherein the step size for increasing transmission power (StepU) for an erroneous TPC command is set to the value of StepU_N.

8. A method as claimed in claim 7, further wherein if step 2 is performed and if the reception quality is not greater than threshold_N, then setting the step size for increasing transmission power (StepU) to a predetermined value.

9. A method as claimed in claim 8, wherein the step size for increasing transmission power (StepU) is set to the value of StepU_N.

10. A method as claimed in claim 9, further wherein the transmission power of the transmitter is increased or decreased depending upon the value of the transmission power control command (TPC) and wherein the size of the increase or decrease of the transmission power is set to the selected step size (StepU or StepD).

11. A method as claimed in claim 5, further wherein the transmission power of the transmitter is increased or decreased depending upon the value of the transmission power control command (TPC) and wherein the size of the increase or decrease of the transmission power is set to the selected step size (StepU or StepD).

12. A method as claimed in claim 1, further wherein if the reception quality is not greater than threshold_N, then setting the step size for increasing transmission power (StepU) to a predetermined value.

13. A method as claimed in claim 12, wherein the step size for increasing transmission power (StepU) is set to the value of StepU_N.

14. A method as claimed in claim 5, wherein the reception quality of the received signal is the signal-to-interference ratio (SIR) value of the received signal.

15. A method as claimed in claim 1, wherein the reception quality of the received signal is the signal-to-interference ratio (SIR) value of the received signal.

16. A method as claimed in claim 1, wherein step size StepU_i and step size StepD_i are the same for at least when i is equal to N.

17. A method as claimed in claim 1, wherein step size StepU_i and step size StepD_i are not equal to each other for at least one value of i if i is less than N.

18. A method as claimed in claim 1, further wherein if the reception quality is not greater than threshold_N, then setting the step size for increasing transmission power (StepU) to a predetermined value.

19. A method as claimed in claim 18, wherein the step size for increasing transmission power (StepU) is set to the value of StepU_N.

20. A device to select the step size for increasing (StepU) the transmission power and the step size for decreasing (StepD) the transmission power of a transmitter based upon the reception quality of a received signal, comprising:

means for determining the reception quality of a received signal;

means for comparing the reception quality of the received signal to a plurality of threshold values so as to generate an output signal indicative of such comparison wherein the comparing means for each integer i, where i ranges from one to N, where N is an integer greater than one, compares the reception quality to a threshold_i, and if this threshold_i is exceeded then generating the output signal indicative thereof and terminating all further comparisons of reception quality to lower thresholds, if i<

N;

where threshold_{i,i+1, . . . , N} decrease monotonically; and

means for selecting UP and DOWN step sizes (StepU and StepD) based upon the output signal of the comparing means.

21. A device as claimed in claim 20, where the UP step size if threshold_i is exceeded is denoted StepU_i, and further where step size StepU_i≧

StepU_i+1 for all i.

22. A device as claimed in claim 23, where the DOWN step size if threshold_i is exceeded is denoted StepD_i, and further where step size StepD_i≧

StepD_i+1 for all i.

23. A device as claimed in claim 20, where the DOWN step size if threshold_i is exceeded is denoted StepD_i, and further where step size StepD_i≧

StepD_i+1 for all i.

24. A device as claimed in claim 20, further comprising means for determining the value of a transmission power control command (TPC), and wherein if the means for determining the value of the TPC command determines a value which is indicative of an erroneous TPC command, then setting the step size for increasing transmission power (StepU) to a predetermined value and skipping all comparisons between received signal quality and said thresholds (threshold_{i,i+1, . . . N}), and if the value of the TPC command is not indicative of an erroneous TPC command, performing said comparisons between the reception quality of the received signal and said thresholds.

25. A device as claimed in claim 24, wherein the step size for increasing transmission power (StepU) for an erroneous TPC command is set to the value of StepU_N and where the system further comprises means for setting the TPC command to an UP command.

26. A device as claimed in claim 25, further wherein for the comparing means, if the reception quality is not greater than threshold_N, then setting the step size for increasing transmission power (StepU) to a predetermined value.

27. A device as claimed in claim 26, wherein the step size for increasing transmission power (StepU) is set to the value of StepU_N.

28. A device as claimed in claim 27, further comprising means for determining the value of a transmission power control command (TPC), and further wherein the transmission power of the transmitter is increased or decreased depending upon the value of the transmission power control command (TPC) and wherein the size of the increase or decrease of the transmission power is set to the selected step size (StepU or StepD).

29. A device as claimed in claim 20, further comprising means for determining the value of a transmission power control command (TPC), and further wherein if the reception quality is not greater than threshold_N, then setting the step size for increasing transmission power (StepU) to a predetermined value and wherein the system further comprises means for setting the TPC command as an UP command regardless of the TPC command received.

30. A device as claimed in claim 29, wherein the step size for increasing transmission power (StepU) is set to the value of StepU_N.

31. A device as claimed in claim 20, wherein the reception quality of the received signal is the signal-to-interference ratio (SIR) value of the received signal.

32. A device as claimed in claim 20, wherein the reception quality of the received signal is the signal-to-interference ratio (SIR) value of the received signal.

33. A device as claimed in claim 20, wherein step size StepU_i and step size StepD_i are the same for at least when i is equal to N.

34. A device as claimed in claim 20, wherein step size StepU_i and step size StepD_i are not equal to each other for at least one value of i if i is less than N.

35. A system to select the step size for transmission power of a first device comprising the device of claim 20 and further comprising a second device for generating a signal that the first device uses as said received signal.