Outer loop/weighted open-loop power control apparatus for a base station

• US 20020075939A1
• Filed: 02/22/2002
• Published: 06/20/2002
• Est. Priority Date: 03/22/2000
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Inventors: Shin, Sung-Hyuk, Zeira, Ariela, Dick, Steven G.
• Granted Patent: US 6,606,343 B2
• Time in Patent Office: Days
• US Class Current: 375/130
• CPC Class Codes: H04W 52/12 Outer and inner loops
• CPC Class Codes: H04W 52/225 Calculation of statistics, e.g. average, variance
• CPC Class Codes: H04W 52/24 using SIR [Signal to Interference Ratio] or other wireless path parameters

Abstract

Outer loop/weighted open loop power control apparatus controls transmission power levels in a spread spectrum time division duplex communication base station. The base station receives a communication including a transmitted power level and measures its received power level. Based in part on the measured power level and the transmitted power level, a path loss estimate is determined. A quality of the path loss estimate is also determined. The transmission power level for a communication from the base station is based in part on weighting the path loss estimate in response to the estimate'"'"'s quality.

Claims

1. A base station for a spread spectrum time division duplex communication using frames with time slots for communication, comprising:

means for receiving, in a first time slot, a first communication having a transmit power level and measuring a power level of said communication;

means for determining a path loss estimate based in part on said measured power level and said received power level;

means for setting a transmission power level for transmission of a second communication in a second time slot based in part on the path loss estimate weighted by a first factor and a long term path loss estimate weighted by a second factor, said first and second factors being a function of a time separation of the first and second time slots; and

means for transmitting the second communication in the second time slot at the set transmission power level.

2. The base station of claim 1 further comprising:

means for determining the long term path loss estimate based at least in part upon an average of path loss estimates of communications sent from the first station to the second station.

3. The base station of claim 2 wherein the first station further comprises:

means for determining a quality, a, of the path loss estimate which is based in part on a number of time slots, D, between the first and second time slot; and

wherein the first factor is α and

the second factor is 1−

α

.

4. The base station of claim 3 wherein a maximum time slot delay is D_max and α

is determined by;

α

=1−

(D−

1)/(D_max−

1).

5. The base station of claim 3 wherein a maximum allowed time slot delay is D_max-allowed and the determined quality, α

, is determined by;

α

=max {1−

(D−

1)/(D_max-allowed−

1), 0}.

6. A base station for use in a spread spectrum time division duplex communication system, using frames with time slots for communication, comprising:

a device for receiving a first communication in a first time slot and transmitting an amplified second communication in a second time slot;

a channel estimation device having an input receiving said first communication for producing channel information;

a data estimation device responsive to said first communication and said channel information for producing interpreted data;

a power measurement device responsive to said channel information for determining a received power level of the first communication;

a path loss estimation device responsive to said measured power level for producing a path loss estimate of the first communication;

a quality measurement device for producing a quality measurement based at least in part upon a time separation of the first time slot and a second time slot;

a transmit power calculation device responsive to said path loss estimate and said quality measurement for producing a power control signal based at least in part upon said path loss estimate weighted by a first factor and a long term path loss estimate weighted by a second factor, wherein the first and second factors are based in part on the quality measurement; and

an amplifier receiving the power control signal and a second communication to be transmitted in the second time slot for amplifying the second communication responsive to the power control signal to produce the amplified second communication for transmission by said receiving device.

7. The base station of claim 6 further comprising:

a data generator for producing communication data;

a spreading and training sequence insertion device having an input receiving the communication data for producing the second communication in the second time slot; and

a modulator having an input receiving the amplified second communication for modulating the amplified second communication to radio frequency prior to transmission.

8. The base station of claim 6 further comprising:

a demodulator having an input receiving the received first communication for producing a baseband signal; and

wherein the channel estimation device and the data estimation device each have an input receiving the baseband signal.

9. The base station of claim 6 wherein the quality measurement is in the range of zero to one and the first factor is the quality measurement and the second factor is one minus the quality measurement.