SYSTEMS AND METHODS FOR PERFORMING OUTER LOOP POWER CONTROL IN WIRELESS COMMUNICATION SYSTEMS

• US 20080194286A1
• Filed: 04/22/2008
• Published: 08/14/2008
• Est. Priority Date: 02/18/2003
• Status: Abandoned Application

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Jou, Yu-Cheun, Chen, Tao, Sarkar, Sandip, Lundby, Stein
• Application Number:
  US12/107,268
• Publication Number:
  US 20080194286A1
• Time in Patent Office: Days
• US Class Current: 455/522
• CPC Class Codes: H04W 52/38 TPC being performed in particular situations
• CPC Class Codes: H04W 52/44 in connection with interruption of transmission

Abstract

Systems and methods for controlling the power level for a mobile station during periods when no data is being transmitted by the mobile station. In one embodiment, data is intermittently transmitted from a mobile station to a base station on a reverse-link traffic channel. When data is being transmitted on the traffic channel, the transmitted data is used by the base station to perform power control operations (e.g., incrementing or decrementing the mobile station'"'"'s power level, based upon comparison of a received SNR to a target SNR). When no data is being transmitted on the traffic channel, a “zero-rate indicator” is transmitted on the rate indicator channel. The zero-rate indicator is used by the base station to perform power control. Power control based on the zero-rate indicator may use velocity profiles, reliability metrics or other techniques to control adjustment of the power level.

Claims

1. A base station operable to communicate with a mobile station via a wireless communication channel, wherein the base station comprises:

a processing subsystem; and

a transceiver subsystem coupled to the processing subsystem and configured to receive data on a reverse link traffic channel and a reverse link rate indicator channel;

wherein when the base station receives data on the reverse-link traffic channel, the base station performs power control based on the received data and when the base station receives no data on the reverse-link traffic channel, the base station performs power control based on the zero-rate indicator.

2. The base station of claim, 1, wherein the base station conforms to a release of the cdma2000 specification.

3. The base station of claim, 2, wherein the reverse-link traffic channel comprises a reverse-link enhanced supplemental channel (R-ESCH).

4. The base station of claim, 2, wherein the reverse-link indicator channel comprises a reverse-link rate indicator channel (R-RICH).

5. The base station of claim, 1, wherein when the base station receives data on the reverse-link traffic channel, the base station is configured to perform power control by directing a mobile station from which the data is received to increase a power level associated with the mobile station when the received data has a signal to noise ratio (SNR) below a target SNR and to decrease the power level associated with the mobile station when the received data has a SNR above the target SNR.

6. The base station of claim, 1, wherein when the base station does not receive data on the reverse-link traffic channel, the base station is configured to perform power control by computing a reliability metric for the zero-rate indicator and incrementing a power level for a mobile station from which the zero-rate indicator is received when the reliability metric indicates that the zero-rate indicator is not reliable, and decrementing the power level when the reliability metric indicates that the zero-rate indicator is reliable.

7. The base station of claim, 1, wherein when the base station does not receive data on the reverse-link traffic channel, the base station is configured to perform power control by computing a velocity profile for a mobile station from which the zero-rate indicator is received based upon the power of the zero-rate indicator and adjusting a power level for the mobile station based upon the computed velocity profile.

8. The base station of claim, 1, wherein when the base station does not receive data on the reverse-link traffic channel, the base station is configured to perform power control by computing a power density for the zero-rate indicator and adjusting a power level for a mobile station from which the zero-rate indicator is received based upon the computed power density.

9. A method implemented in a base station operable to communicate with a mobile station via a wireless communication link, wherein the method comprises:

when traffic is being received on a reverse-link traffic channel, controlling a power level based on the traffic being transmitted on the reverse-link traffic channel; and

when traffic is not being received on the reverse-link traffic channel, receiving a periodically transmitted zero-rate indicator on a reverse-link rate indicator channel, and

controlling the power level based on the zero-rate indicator.

10. The method of claim, 9, wherein the reverse-link traffic channel comprises a cdma2000 reverse-link enhanced supplemental channel (R-ESCH).

11. The method of claim, 9, wherein the reverse-link indicator channel comprises a cdma2000 reverse-link rate indicator channel (R-RICH).

12. The method of claim, 9, wherein controlling the power level based on the traffic being transmitted on the reverse-link traffic channel comprises directing a mobile station from which the data is received to increase a power level associated with the mobile station when the received data has a signal to noise ratio (SNR) below a target SNR and to decrease the power level associated with the mobile station when the received data has a SNR above the target SNR.

13. The method of claim, 9, wherein controlling the power level based on the zero-rate indicator comprises computing a reliability metric for the zero-rate indicator and incrementing a power level for a mobile station from which the zero-rate indicator is received when the reliability metric indicates that the zero-rate indicator is not reliable, and decrementing the power level when the reliability metric indicates that the zero-rate indicator is reliable.

14. The method of claim, 9, wherein controlling the power level based on the zero-rate indicator comprises computing a velocity profile for a mobile station from which the zero-rate indicator is received based upon the power of the zero-rate indicator and adjusting a power level for the mobile station based upon the computed velocity profile.

15. The method of claim, 9, wherein controlling the power level based on the zero-rate indicator comprises computing a power density for the zero-rate indicator and adjusting a power level for a mobile station from which the zero-rate indicator is received based upon the computed power density.