Power control in a wireless communication system

• US 20060035660A1
• Filed: 08/12/2004
• Published: 02/16/2006
• Est. Priority Date: 08/12/2004
• Status: Active Grant

• Current Assignee: Intellectual Ventures II LLC (Intellectual Ventures LLC)
• Original Assignee: Intellectual Ventures Holding 81 LLC (Intellectual Ventures LLC)
• Inventors: Anderson, Nicholas William
• Granted Patent: US 8,897,828 B2
• Time in Patent Office: Days
• US Class Current: 455/522
• CPC Class Codes: H04W 52/06 TPC algorithms
• CPC Class Codes: H04W 52/08 Closed loop power control
• CPC Class Codes: H04W 52/10 Open loop power control
• CPC Class Codes: H04W 52/12 Outer and inner loops
• CPC Class Codes: H04W 52/221 using past power control commands
• CPC Class Codes: H04W 52/24 using SIR [Signal to Interference Ratio] or other wireless path parameters
• CPC Class Codes: H04W 52/241 taking into account channel quality metrics, e.g. SIR, SNR, CIR, Eb/lo
• 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 72/0473 the resource being transmission power
• CPC Class Codes: H04W 72/1268 of uplink data flows
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal

Abstract

A method, system and apparatus for setting a transmit power control level in a wireless communication system. Aspects of both open loop and closed loop transmit power control schemes are used to determine a transmit power level. A method includes measuring a power level of a received signal, receiving a transmit power control (TPC) command, and calculating a transmit power level based on the power level of the received signal and the TPC command.

Claims

1. A method of power control in a radio communications system, the method comprising:

determining a path loss of a radio channel between a base station and a remote transceiver;

receiving a transmit power control (TPC) command transmitted to the remote transceiver from the base station; and

calculating a transmit power level for the remote transceiver based on the path loss and the TPC command.

2. The method of power control of claim 1, the method further comprising transmitting an uplink signal from the remote transceiver at the calculated transmit power level.

3. The method of power control of claim 1, wherein determining the path loss includes:

receiving a downlink signal transmitted from the base station, wherein the downlink signal signals a transmitted power level of the downlink signal; and

measuring a received power level of the downlink signal.

4. The method of power control of claim 3, wherein determining the path loss further includes computing a difference between the signalled transmit power level and the measured received power level.

5. The method of power control of claim 1, the method further comprising:

generating the TPC command; and

transmitting the TPC command from the base station.

6. The method of power control of claim 1, wherein the calculating the transmit power level is additionally based on an adjustment factor.

7. The method of power control of claim 6, wherein the adjustment factor incorporates a spreading factor parameter.

8. The method of power control of claim 6, wherein the adjustment factor incorporates a selected transport format parameter.

9. A method of power control in a radio communications system, the method comprising:

receiving a signal at a second transceiver transmitted from a first transceiver;

measuring a power level of the received signal;

receiving a transmit power control (TPC) command at the second transceiver transmitted from the first transceiver; and

calculating a transmit power level for the second transceiver based on the power level of the received signal and the TPC command.

10. A method of uplink power control in a CDMA radio communications system, the method comprising:

receiving an uplink signal;

measuring a received SNIR of the uplink signal;

comparing the measured received SNIR with an SNIR target;

assigning a first value to a step indicator if the measured received SNIR is greater than the SNIR target, and assigning a second value to a step indicator if the measured received SNIR is less than the SNIR target;

transmitting a transmit power control (TPC) command instructing a transmitter to adjust an uplink transmit power level based on the step indicator;

receiving the TPC command including the step indicator;

accumulating the step indicator value;

broadcasting a downlink signal including an indication of a downlink power level, wherein the signal is transmitted at the downlink power level;

measuring the received power of the downlink signal; and

setting a transmit power level based on the received power level, the indication of the downlink power level, and the accumulated step indicator value.

11. The method of power control of claim 10, further comprising:

determining an error metric of the uplink signal;

updating the SNIR target based on the error metric;

measuring an interference value in the received uplink signal; and

updating an interference measurement table with the interference value;

wherein broadcasting the downlink signal further includes the interference measurement table; and

wherein setting the transmit power level is further based on a value in the interference measurement table.

12. A method comprising:

measuring a power level of a received signal;

receiving a transmit power control (TPC) command; and

calculating a transmit power level based on the power level of the received signal and the TPC command.

13. A radio comprising:

a receiver including an output to provide a measured received power level;

an accumulator having an input for accepting step increase and decrease instructions and an output providing a sum of past step instructions;

a power level setting circuit coupled to the accumulator output and coupled to the receiver output, wherein the power level setting circuit sets a transmit power bases on the accumulator output and the measured received power level; and

a transmitter, wherein the transmitter transmits a signal at the set transmit power.