Reverse link power control in an orthogonal system

• US 7,962,826 B2
• Filed: 07/16/2009
• Issued: 06/14/2011
• Est. Priority Date: 07/20/2004
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Agrawal, Avneesh, Sutivong, Arak
• Primary Examiner(s): Chase; Shelly A
• Application Number:
  US12/504,085
• Publication Number:
  US 20090274232A1
• Time in Patent Office: 698 Days
• Field of Search: 714748-749, 714/18, 375/135, 375/297
• US Class Current: 714/748
• CPC Class Codes: H04W 52/12 Outer and inner loops
• CPC Class Codes: H04W 52/146 Uplink power control
• CPC Class Codes: H04W 52/20 using error rate
• CPC Class Codes: H04W 52/24 using SIR [Signal to Interference Ratio] or other wireless path parameters
• CPC Class Codes: H04W 52/286 during data packet transmission, e.g. high speed packet access [HSPA]
• CPC Class Codes: H04W 52/367 Power values between minimum and maximum limits, e.g. dynamic range
• CPC Class Codes: H04W 52/48 during retransmission after error or non-acknowledgment

Abstract

A closed-loop reverse-link power control algorithm for a frequency hopping orthogonal frequency division multiple access (FH-OFDMA) system is described. The power control algorithm adjusts the user'"'"'s transmit power based on effective carrier-to-interference (C/I) and Received-Power-Over-Thermal (RpOT) measurements. The algorithm is inherently stable and is effective for FH-OFDMA systems with retransmissions.

Claims

1. A method of reverse link power control, comprising:

enabling an outer loop power control when a data channel is present, wherein the outer loop power control comprises;

transmitting a packet;

determining whether the packet has been received without error;

decreasing an effective carrier-to-interference (C/I) setpoint if the packet has been received without error;

increasing the effective C/I setpoint if the packet has not been received without error;

enabling an inner loop power control, wherein the inner loop power control comprises;

regulating the transmit (TX) power based on a Received Power Over Thermal (RpOT) and the effective C/I setpoint; and

disabling the outer loop power control while maintaining the inner loop power control when no data channel is present.

2. The method of claim 1, wherein the Received Power Over Thermal (RpOT) is the ratio between the received signal power and thermal noise.

3. The method of claim 1, further comprising issuing a down command if the RpOT is greater than the RpOT_max.

4. The method of claim 1, further comprising determining whether an effective carrier-to-interference ratio (C/I) is less than an effective carrier-to-interference ratio for the setpoint (C/I_sp).

5. The method of claim 4, further comprising determining whether a Received Power Over Thermal (RpOT) is less than a minimum Received Power Over Thermal (RpOT_min).

6. The method of claim 5, further comprising issuing a down command if the effective carrier-to-interference ratio (C/I) is not less than the effective carrier-to-interference ratio for the setpoint (C/I_sp) or the Received Power Over Thermal (RpOT) is not less than the minimum Received Power Over Thermal (RpOT_min).

7. The method of claim 5, further comprising issuing an up command if the effective carrier-to-interference ratio (C/I) is less than the effective carrier-to-interference ratio for the setpoint (C/I_sp) and the Received Power Over Thermal (RpOT) is less than the minimum Received Power Over Thermal (RpOT_min).

8. A wireless communications device, comprising:

means for enabling an outer loop power control when a data channel is present, wherein the outer loop power control comprises;

means for transmitting a packet;

means for determining whether the packet has been received without error;

means for decreasing an effective carrier-to-interference (C/I) setpoint if the packet has been received without error;

means for increasing the effective C/I setpoint if the packet has not been received without error;

means for enabling an inner loop power control, wherein the inner loop power control comprises;

means for determining whether a Received Power Over Thermal (RpOT) is greater than a maximum Received Power Over Thermal (RpOT_max); and

means for disabling the outer loop power control while maintaining the inner loop power control when no data channel is present.

9. A processor programmed to execute a method of estimating interference in a wireless communication system, the method comprising:

enabling an outer loop power control when a data channel is present, wherein the outer loop power control comprises;

transmitting a packet;

determining whether the packet has been received without error;

decreasing an effective carrier-to-interference (C/I) setpoint if the packet has been received without error;

increasing the effective C/I setpoint if the packet has not been received without error;

enabling an inner loop power control, wherein the inner loop power control comprises;

regulating the transmit (TX) power based on a Received Power Over Thermal (RpOT) and the effective C/I setpoint; and

disabling the outer loop power control while maintaining the inner loop power control when no data channel is present.

10. A computer readable media comprising instructions stored thereon, wherein the instructions, when executed, comprise a method comprising:

enabling an outer loop power control when a data channel is present, wherein the outer loop power control comprises;

transmitting a packet;

determining whether the packet has been received without error;

decreasing an effective carrier-to-interference (C/I) setpoint if the packet has been received without error;

increasing the effective C/I setpoint if the packet has not been received without error;

enabling an inner loop power control, wherein the inner loop power control comprises;

regulating the transmit (TX) power based on a Received Power Over Thermal (RpOT) and the effective C/I setpoint; and

disabling the outer loop power control while maintaining the inner loop power control when no data channel is present.