Power control for reverse packet data channel in CDMA systems

• US 7,299,402 B2
• Filed: 02/13/2004
• Issued: 11/20/2007
• Est. Priority Date: 02/14/2003
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Yoon, Young C., Tsai, Shiau-He Shawn, Soong, Anthony C. K., Oh, Seong-Jun
• Primary Examiner(s): Baker; Stephen M.
• Application Number:
  US10/779,518
• Publication Number:
  US 20040193971A1
• Time in Patent Office: 1,376 Days
• Field of Search: 370/522, 455/522, 714/807
• US Class Current: 714/807
• CPC Class Codes: H04L 1/0002 by adapting the transmission rate
• CPC Class Codes: H04L 1/0025 Transmission of mode-switching indication
• CPC Class Codes: H04L 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 1/0039 other detection of signalling, e.g. detection of TFCI explicit signalling H04L1/0046, H04L27/0012 and H04L25/0262 take precedence
• CPC Class Codes: H04L 1/0081 Formats specially adapted to avoid errors in the feedback channel H04L1/1607 takes precedence
• CPC Class Codes: H04L 1/08 by repeating transmission, e.g. Verdan system H04L1/1858 and H04L1/189 take precedence
• CPC Class Codes: H04L 1/20 using signal quality detector
• CPC Class Codes: H04W 52/146 Uplink power control
• CPC Class Codes: H04W 52/16 Deriving transmission power values from another channel
• CPC Class Codes: H04W 52/20 using error rate
• CPC Class Codes: H04W 52/267 taking into account the information rate
• CPC Class Codes: H04W 52/325 Power control of control or pilot channels

Abstract

A method of reverse link power control for a reverse packet data channel in a wireless communication system allows a mobile station to autonomously change its data transmission rate. The mobile station transmits packet data over a reverse packet data channel having a data rate variant transmit power level that varies based on a transmit data rate on the packet data channel. The mobile station further transmits control signals over a reverse control channel associated with the reverse packet data channel. The transmit power level of the reverse control channel is such that the transmit power level does not vary with the transmit data rate on the packet data channel. The radio base station measures the strength of the received signals on the reverse control channel, compares the measured strength to a power control set point, and generates a power control signal responsive to the comparison of the control signal to the power control set point.

Claims

1. A method of transmit power control in a mobile station, the method comprising:

transmitting traffic signals over a data rate variant reverse traffic channel having a transmit power level that varies depending on a data transmission rate on the reverse traffic channel;

transmitting a control signal over a data rate invariant reverse control channel having a data rate that does not change with the data transmission rate on the reverse traffic channel; and

changing the transmit power level of the mobile station on the reverse traffic channel responsive to a change in the data transmission rate on the reverse traffic channel while maintaining the transmit power level on the reverse control channel at a current transmit power level for the control channel.

2. The method of claim 1 further comprising encoding control information transmitted on the reverse control channel with an error detection code to enable detection of frame errors at a receiver.

3. The method of claim 2 wherein encoding control information with the error detection code to enable detection of errors at the receiver comprises encoding the control information with a cyclic redundancy check code.

4. The method of claim 1 further comprising transmitting a pilot signal on a reverse pilot channel.

5. The method of claim 4 further comprising changing the transmit power level of the pilot signal responsive to a change in the data transmission rate, and slaving the transmit power level of the reverse traffic channel to the reverse pilot channel.

6. The method of claim 5 further comprising adjusting the channel gain of the reverse control channel relative to the reverse pilot channel responsive to a change in the data transmission rate so that the transmit power level of the reverse control channel does not change.

7. A mobile station comprising:

a transmitter for transmitting traffic signals over a data rate variant reverse traffic channel having a transmit power level that varies depending on a data transmission rate on the reverse traffic channel, and for transmitting a control signal over a data rate invariant reverse control channel having a data rate that does not change with the data transmission rate on the reverse traffic channel;

a receiver to receive power control signals from a radio base station; and

a control unit for controlling the transmit power level of the mobile station based on the power control signals, the control unit being operative to adjust the transmit power level of the mobile station on the reverse traffic channel responsive to a change in the data transmission rate on the reverse traffic channel while maintaining the transmit power level on the reverse control channel at a current transmit power level for the reverse control channel.

8. The mobile station of claim 7 wherein the control unit further encodes control information transmitted on the reverse control channel with an error detection code to enable detection of frame errors at a receiver.

9. The mobile station of claim 8 wherein the control unit encodes control information with a cyclic redundancy check code.

10. The mobile station of claim 7 wherein the transmitter transmits a pilot signal on a reverse pilot channel.

11. The mobile station of claim 10 further wherein the control unit adjusts the transmit power level of the pilot signal responsive to a change in the data transmission rate on the reverse traffic channel.

12. The method of claim 11 further wherein the control unit adjusts the channel gain of the reverse control channel relative to the reverse pilot channel responsive to the change in the data transmission rate so that the transmit power level of the reverse control channel does not change.