Uplink (UL) power control apparatus and method in broadband wireless communication system

• US 7,885,678 B2
• Filed: 05/11/2007
• Issued: 02/08/2011
• Est. Priority Date: 05/12/2006
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Maeng, Seung-Joo, Jang, Ji-Ho, Jeon, Jae-Ho, You, Hwa-Sun
• Primary Examiner(s): Urban; Edward
• Assistant Examiner(s): Alam; Fayyaz
• Application Number:
  US11/803,119
• Publication Number:
  US 20070265026A1
• Time in Patent Office: 1,369 Days
• Field of Search: 455/522, 455 69- 70, 370/318, 370/320
• US Class Current: 455/522
• CPC Class Codes: H04W 52/08 Closed loop power control
• CPC Class Codes: H04W 52/10 Open loop power control
• CPC Class Codes: H04W 52/146 Uplink power control
• CPC Class Codes: H04W 52/228 using past power values or information

Abstract

An uplink (UL) power control apparatus and method in a broadband wireless communication system are provided. The Mobile Station (MS) includes a power controller for calculating a power compensation value using a last transmit power in a previous closed loop power control when a power control mode is changed to an open loop power control, and determining a transmit power according to the open loop power control using the power compensation value; and a transmitter for adjusting and transmitting the transmit power of a UL signal under control of the power controller.

Claims

1. A Mobile Station (MS) in a wireless communication system, comprising:

a power controller for acquiring a last transmit power value P<sub>Tx,CL—

last</sub> in a closed loop power control mode, a path loss value L<sub>OL—

init</sub> estimated at the MS, a latest Noise and Interference (NI) value NI<sub>OL—

init</sub> received from a Base Station (BS), a required Carrier to Interference and Noise Ratio value (CINR value) C/N<sub>CL—

last</sub> for a last Modulation and Coding Scheme (MCS) level in the closed loop power control mode, and a repetition factor R<sub>CL—

last</sub> according to the last MCS level, when a power control mode is changed from a closed loop power control to an open loop power control, calculating a power compensation value Offset_SS_perSS using the acquired values, and determining a transmit power level P according to the open loop power control using the power compensation value; and

a transmitter for adjusting a transmit power of an Uplink (UL) signal according to the determined transmit power level P.

2. The MS of claim 1, wherein the power controller calculates the power compensation value Offset_SS_perSS based on

3. The MS of claim 1, wherein the power controller determines a transmit power level P according to the open loop power control based on

4. The MS of claim 1, further comprising:

a power measurer for measuring a receive power of a preamble received from the BS and providing the measured receive power to the power controller,

wherein the power controller estimates UL path loss using the BS transmit power value received from the BS and the receive power fed from the power measurer, and uses the estimated path loss during the open loop power control.

5. The MS of claim 1, wherein the power control mode is changed using a Power control Mode Change ReSPonse (PMC_RSP) message from the BS.

6. The MS of claim 1, wherein the power compensation value Offset_SS_perSS is calculated when the power control mode is changed, and is maintained until the power control mode is changed.

7. An uplink (UL) power control method in a wireless communication system, the method comprising:

calculating a power compensation value using a last transmit power in a previous closed loop power control when a power control mode is changed from a closed loop power control to an open loop power control; and

determining a transmit power according to the open loop power control using the power compensation value,

wherein the power compensation value Offset_SS_perSS is calculated based on

8. An uplink (UL) power control method in a wireless communication system, comprising:

acquiring, when a power control mode is changed from a closed loop power control to an open loop power control, a last transmit power value P<sub>Tx,CL—

last</sub> in a closed loop power control mode, a path loss value L<sub>OL—

init</sub> estimated at a Mobile Station (MS), a latest Noise and Interference (NI) value NI<sub>OL—

init</sub> received from a Base Station (BS), a required CINR value C/N<sub>CL—

last</sub> for a last Modulation and Coding Scheme (MCS) level in the closed loop power control mode, and a number of repetitions R<sub>CL—

last</sub> according to the last MCS level; and

calculating a power compensation value Offset_SS_perSS controlled by the MS using the acquired values; and

determining a transmit power level P according to the open loop power control using the power compensation value Offset_SS_perSS.

9. The UL power control method of claim 8, further comprising:

adjusting a UL signal power level P to the determined transmit power and transmitting the UL signal.

10. The UL power control method of claim 8, wherein the power compensation value Offset_—

SS_perSS is calculated based on

11. The UL power control method of claim 8, wherein a transmit power level P according to the open loop power control is determined based on

12. The UL power control method of claim 8, wherein the power control mode is changed using a Power control Mode Change ReSPonse (PMC_RSP) message from the BS.

13. The UL power control method of claim 8, wherein the power compensation value Offset_SS_perSS is calculated when the power control mode is changed, and is maintained until the power control mode is changed.

14. A power control apparatus in a wireless communication system, comprising:

means for acquiring, when a power control mode is changed from a closed loop power control to an open loop power control, a final transmit power value P<sub>Tx,CL—

last</sub> in a closed loop power control mode, a path loss value L<sub>OL—

init</sub> estimated at a Mobile Station (MS), a latest Noise and Interference (NI) value NI<sub>OL—

init</sub> received from a Base Station (BS), a required CINR value C/N<sub>CL—

last</sub> for a last Modulation and Coding Scheme (MCS) level in the closed loop power control mode, and a number of repetitions R<sub>CL—

last</sub> according to the last MCS level; and

means for calculating a power compensation value Offset_SS_perSS controlled by the MS using the acquired values based on

15. A Mobile Station (MS) in a wireless communication system, comprising:

a power controller for calculating a power compensation value using a final transmit power in a previous closed loop power control when a power control mode is changed from a closed loop power control to an open loop power control, and determining a transmit power according to the open loop power control using the power compensation value; and

a transmitter for adjusting and transmitting the transmit power of an uplink (UL) signal under control of the power controller,

wherein the power controller calculates the power compensation value Offset_SS_perSS based on