Pathloss aided closed loop power control

• US 7,363,049 B2
• Filed: 10/07/2002
• Issued: 04/22/2008
• Est. Priority Date: 10/09/2001
• Status: Expired due to Fees

• Current Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Original Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Inventors: Koo, Chang-Soo, Shin, Sung-Hyuk, Zeira, Ariela, Ozluturk, Fatih
• Primary Examiner(s): Anderson; Matthew
• Assistant Examiner(s): PEREZ, ANGELICA
• Application Number:
  US10/266,882
• Publication Number:
  US 20030068984A1
• Time in Patent Office: 2,024 Days
• Field of Search: 455/522, 455/69, 455/68, 370/318
• US Class Current: 455/522
• CPC Class Codes: H04W 52/08 Closed loop power control
• CPC Class Codes: H04W 52/221 using past power control commands
• CPC Class Codes: H04W 52/226 using past references to control power, e.g. look-up-table
• CPC Class Codes: H04W 52/228 using past power values or information
• CPC Class Codes: H04W 52/242 taking into account path loss
• CPC Class Codes: H04W 52/243 taking into account interferences
• CPC Class Codes: H04W 52/248 where transmission power control commands are generated based on a path parameter
• CPC Class Codes: H04W 52/36 with a discrete range or set of values, e.g. step size, ramping or offsets

Abstract

A transmitting station receives a transmit power command and a reference signal. The transmit power command indicates an increase or decrease in transmission power for the transmitting station. A received power level of the reference signal is measured and the measured reference signal received power level is compared to a transmit power level of the reference signal to produce a pathloss estimate of the reference signal. A size of a change in transmit power level is determined using the pathloss estimate. A transmission power level of the transmitting station is adjusted in response to the transmit power command in an amount of the determined change in size. A communication is transmitted at the adjusted transmission power level.

Claims

1. A method for controlling transmission power levels of a transmitter station, the method comprising:

receiving at the transmitting station a transmit power command and a reference signal, the transmit power command indicating an increase or decrease in transmission power for the transmitting station;

measuring a received power level of the reference signal and comparing the measured reference signal received power level to a transmit power level of the reference signal to produce a pathloss estimate of the reference signal;

determining a size of a change in transmit power level using the produced pathloss estimate, wherein the determining a size of a change in transmit power level is determined by comparing a prior pathloss estimate to the produced pathloss estimate, and wherein the produced and prior pathloss estimates are weighted pathloss estimates and the weighted pathloss estimates are determined by multiplying a measured pathloss estimate by a first factor (α

) and adding the weighted pathloss estimate to a longterm pathloss estimate multiplied by (1−

α

);

adjusting a transmission power level of the transmitting station by increasing or decreasing the transmit power level in response to the transmit power command in an amount of the determined change in size; and

transmitting a communication at the adjusted transmission power level.

2. The method of claim 1 wherein the reference signal and the transmitted communication are transmitted in reciprocal channels.

3. The method of claim 1 wherein the comparing is by taking a difference between the prior and produced pathloss.

4. The method of claim 3 wherein the size of the change in transmit power is determined by comparing the pathloss difference to thresholds and selecting the size based on between which thresholds the pathloss difference falls.

5. The method of claim 1 wherein the time period is a number of timeslots between the measuring of the measured pathloss estimate and a time slot of transmission of the communication.

6. The method of claim 5 for use in a time division synchronous code division multiple access communication system.

7. The method of claim 5 for use in a time division duplex/code division multiple access communication system.

8. A user equipment comprising:

a transmit power command receiver and judgment device for receiving a transmit power command and determining a value of the received transmit power command, the transmit power command indicating an increase or decrease in transmission power;

an antenna for receiving a reference signal and radiating a communication;

a reference signal power measurement device for measuring a received power level of the reference signal;

a pathloss determination device for comparing the measured reference signal received power level to a transmit power level of the reference signal to produce a pathloss estimate of the reference signal;

a transmit power control determination device for determining a size of a change in transmit power level using the produced pathloss estimate and for determining an adjustment in a transmission power level by increasing or decreasing the transmit power level in response to the transmit power command in an amount of the determined change in size, wherein the determining a size of a change in transmit power level is determined by comparing a prior pathloss estimate to the produced pathloss estimate, and wherein the produced and prior pathloss estimates are weighted pathloss estimates and the weighted pathloss estimates are determined by multiplying a measured pathloss estimate by a first factor (α

) and adding the weighted pathloss estimate to a longterm pathloss estimate multiplied by (1−

α

);

a modulation and spreading device for producing the communication; and

an amplifier for adjusting a transmission power level of the communication based on the adjustment in transmission power level.

9. The user equipment of claim 8 wherein the reference signal and the transmitted communication are transmitted in reciprocal channels.

10. The user equipment of claim 8 wherein the comparing is by taking a difference between the prior and produced pathloss.

11. The user equipment of claim 10 wherein the size of the change in transmit power is determined by comparing the pathloss difference to thresholds and selecting the size based on between which thresholds the pathloss difference falls.

12. The user equipment of claim 8 wherein the time period is a number of timeslots between the measuring of the measured pathloss estimate and a time slot of transmission of the communication.

13. The user equipment of claim 12 wherein the communication is transmitted in a time division synchronous code division multiple access format.

14. The user equipment of claim 12 wherein the communication is transmitted in a time division duplex/code division multiple access format.

15. A base station comprising:

a transmit power command receiver and judgment device for receiving a transmit power command and determining a value of the received transmit power command, the transmit power command indicating an increase or decrease in transmission power;

an antenna for receiving a reference signal and radiating a communication;

a reference signal power measurement device for measuring a received power level of the reference signal;

a pathloss determination device for comparing the measured reference signal received power level to a transmit power level of the reference signal to produce a pathloss estimate of the reference signal;

a transmit power control determination device for determining a size of a change in transmit power level using the produced pathloss estimate and for determining an adjustment in a transmission power level by increasing or decreasing the transmit power level in response to the transmit power command in an amount of the determined change in size, wherein the determining a size of a change in transmit power level is determined by comparing a prior pathloss estimate to the produced pathloss estimate, and wherein the produced and prior pathloss estimates are weighted pathloss estimates and the weighted pathloss estimates are determined by multiplying a measured pathloss estimate by a first factor (α

) and adding the weighted pathloss estimate to a longterm pathloss estimate multiplied by (1−

α

);

a modulation and spreading device for producing the communication; and

an amplifier for adjusting a transmission power level of the communication based on the adjustment in transmission power level.

16. The base station of claim 15 wherein the reference signal and the transmitted communication are transmitted in reciprocal channels.

17. The base station of claim 15 wherein the comparing is by taking a difference between the prior and produced pathloss.

18. The base station of claim 17 wherein the size of the change in transmit power is determined by comparing the pathloss difference to thresholds and selecting the size based on between which thresholds the pathloss difference falls.

19. The base station of claim 15 wherein the time period is a number of timeslots between the measuring of the measured pathloss estimate and a time slot of transmission of the communication.

20. The base station of claim 19 wherein the communication is transmitted in a time division synchronous code division multiple access format.

21. The base station of claim 19 wherein the communication is transmitted in a time division duplex/code division multiple access format.