Power control for a wireless communication system utilizing orthogonal multiplexing

• US 8,478,202 B2
• Filed: 05/15/2008
• Issued: 07/02/2013
• Est. Priority Date: 06/18/2004
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Sutivong, Arak, Julian, David Jonathan, Agrawal, Avneesh
• Primary Examiner(s): Maung, Nay A
• Assistant Examiner(s): Perez, Angelica
• Application Number:
  US12/121,405
• Publication Number:
  US 20080214121A1
• Time in Patent Office: 1,874 Days
• Field of Search: 455/522, 455/69, 455/67.13, 455/68, 455/63.1, 455/501, 455/114.2, 375/144, 375/148, 375/346, 375/254, 375/278, 375/296, 375/284, 370/317, 370/318, 370/320
• US Class Current: 455/67.13
• CPC Class Codes: H04B 17/309 Measuring or estimating channel quality parameters
• CPC Class Codes: H04L 1/0045 Arrangements at the receiver end
• CPC Class Codes: H04L 1/0057 Block codes H04L1/0061, H04L1/0064 take precedence
• CPC Class Codes: H04L 1/20 using signal quality detector
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 28/04 Error control
• CPC Class Codes: H04W 52/125 cascaded outer loop power control
• 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 52/24 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 52/247 where the output power of a terminal is based on a path parameter sent by another terminal
• CPC Class Codes: H04W 52/283 Power depending on the position of the mobile
• CPC Class Codes: H04W 52/36 with a discrete range or set of values, e.g. step size, ramping or offsets
• CPC Class Codes: H04W 52/362 Aspects of the step size
• CPC Class Codes: H04W 52/367 Power values between minimum and maximum limits, e.g. dynamic range
• CPC Class Codes: H04W 52/54 Signalisation aspects of the TPC commands, e.g. frame structure
• CPC Class Codes: H04W 52/60 : using different transmission rates for TPC commands
• CPC Class Codes: H04W 88/08 : Access point devices

Abstract

Techniques for adjusting transmit power to mitigate both intra-sector interference to a serving base station and inter-sector interference to neighbor base stations are described. The amount of inter-sector interference that a terminal may cause may be roughly estimated based on the total interference observed by each neighbor base station, channel gains for the serving and neighbor base stations, and the current transmit power level. The transmit power may be decreased if high interference is observed by a neighbor base station and increased otherwise. The transmit power may be adjusted by a larger amount and/or more frequently if the terminal is located closer to the neighbor base station observing high interference and/or if the current transmit power level is higher, and vice versa. The intra-sector interference is maintained within an acceptable level by limiting a received SNR for the terminal to be within a range of allowable SNRs.

Claims

1. A method of reporting interference in a wireless communication system, comprising:

estimating interference observed at a base station;

forming an interference report for the estimated interference;

broadcasting the interference report via a wireless channel;

comparing the estimated interference against a first nominal interference threshold;

setting a first bit based on whether the estimated interference is above or below the first nominal interference threshold, and wherein the interference report comprises the first bit;

comparing the estimated interference against a second high interference threshold that is higher than the first nominal interference threshold; and

setting a second bit based on whether the estimated interference is above the second high interference threshold, and wherein the interference report further comprises the second bit.

2. The method of claim 1, wherein the interference excludes signal power received at the base station which was transmitted by terminals.

3. A method of reporting interference in a wireless communication system, comprising:

estimating interference observed at a base station, comprising;

obtaining an interference estimate for each of a plurality of subbands at the base station, and

deriving the estimated interference based on a plurality of interference estimates for the plurality of subbands;

forming an interference report for the estimated interference;

broadcasting the interference report via a wireless channel comparing the estimated interference against a first nominal interference threshold;

setting a first bit based on whether the estimated interference is above or below the first nominal interference threshold, and wherein the interference report comprises the first bit;

comparing the estimated interference against a second high interference threshold that is higher than the first nominal interference threshold; and

setting a second bit based on whether the estimated interference is above the second high interference threshold, and wherein the interference report further comprises the second bit.

4. The method of claim 3, wherein the estimated interference is an arithmetic average of the plurality of interference estimates for the plurality of subbands.

5. The method of claim 3, wherein the estimated interference is a geometric average of the plurality of interference estimates for the plurality of subbands.

6. The method of claim 3, wherein the estimated interference is obtained based on a capacity-based averaging of the plurality of interference estimates for the plurality of subbands.

7. The method of claim 3, wherein the interference excludes signal power received transmitting to at the base station which was transmitted by terminals.

8. An apparatus in a wireless communication system, comprising:

an interference estimator operative to estimate interference observed at a base station;

a controller operative to form an interference report for the estimated interference;

a data processor operative to

process the interference report for broadcast via a wireless channel;

compare the estimated interference against a first nominal interference threshold;

set a first bit based on whether the estimated interference is above or below the first nominal interference threshold, and wherein the interference report comprises the first bit;

compare the estimated interference against a second high interference threshold that is higher than the first nominal interference threshold; and

set a second bit based on whether the estimated interference is above the second nominal interference threshold, and wherein the interference report further comprises the second bit.

9. An apparatus in a wireless communication system, comprising:

means for estimating interference observed at a base station;

means for forming an interference report for the estimated interference;

means for broadcasting the interference report via a wireless channel;

means for comparing the estimated interference against a first nominal interference threshold;

means for setting a first bit based on whether the estimated interference is above or below the first nominal interference threshold, and wherein the interference report comprises the first bit;

means for comparing the estimated interference against a second high interference threshold that is higher than the first nominal interference threshold; and

means for setting a second bit based on whether the estimated interference is above the second high interference threshold, and wherein the interference report further comprises the second bit.

10. A non transitory computer readable medium storing instructions for execution by a processor, the instructions comprising:

estimating interference observed at a base station;

forming an interference report for the estimated interference;

broadcasting the interference report via a wireless channel;

comparing the estimated interference against a first nominal interference threshold;

setting a first bit based on whether the estimated interference is above or below the first nominal interference threshold, and wherein the interference report comprises the first bit;

comparing the estimated interference against a second high interference threshold that is higher than the first nominal interference threshold; and

setting a second bit based on whether the estimated interference is above the second high interference threshold, and wherein the interference report further comprises the second bit.