METHOD AND APPARATUS FOR ESTIMATING REVERSE LINK LOADING IN A WIRELESS COMMUNICATION SYSTEM

• US 20070270100A1
• Filed: 10/27/2006
• Published: 11/22/2007
• Est. Priority Date: 10/27/2005
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Agrawal, Avneesh, Black, Peter, Milikovsky, Dmitry
• Granted Patent: US 8,929,908 B2
• Time in Patent Office: Days
• US Class Current: 455/67.110
• CPC Class Codes: H04B 17/345 Interference values signal-to-interference ratio [SIR] or carrier-to-interference ratio [CIR] H04B17/336
• CPC Class Codes: H04B 17/382 for resource allocation, admission control or handover

Abstract

Method and apparatus for estimating reverse link loading in a wireless communication system. The reverse link interference is measured and reverse link receiver noise is measured. The reverse link interference is compared to the reverse link receiver noise, for example, by dividing the interference power by the receiver noise power. The reverse link receiver noise can be measured in an orthogonal frequency division multiple access (OFDMA) system by nulling transmission from access terminals within the cell and nearby during a null time and frequency interval. Power measure in the null time and frequency interval is receiver noise power. The reverse link interference can be measure by several means. For example, local null time and frequency intervals can be designated. The access terminals within the cell null their transmissions during the local time and frequency intervals. Access terminals outside the cell continue to transmit during the local time and frequency intervals. Power measured in the local time and frequency interval is interference power. As another example, interference power can be measured by subtracting pairs of pilot symbols that are contiguous to each other in time or frequency.

Claims

1. A method of calculating a reverse link loading in an orthogonal frequency division multiple access wireless communication system, the method comprising:

estimating interference from at least one access terminal not being served by an access point;

measuring a receiver noise in a null time and frequency interval, the null time and frequency interval comprising at least one tone of the orthogonal frequency division multiple access wireless communication system; and

comparing the interference to the receiver noise.

2. The method of claim 1, wherein the measuring comprises:

measuring a first received power outside the null time and frequency interval.

3. The method of claim 2, wherein the estimating interference comprises:

measuring a second received power in the null time and frequency interval.

4. A method of controlling a transmission power, the method comprising:

performing the method of claim 1;

and

increasing the transmission power responsive to the comparing.

5. A method of responding to an admission request, the method comprising:

performing the method of claim 1;

and

denying the admission request responsive to the comparing.

6. A method of controlling a data rate, the method comprising:

performing the method of claim 1;

and

decreasing the data rate responsive to the comparing.

7. The method of claim 1, wherein the comparing comprises dividing the interference by the receiver noise.

8. The method of claim 1, wherein the estimating interference from at least one access terminal not being served by an access point comprises:

detecting a first pilot signal;

detecting a second pilot signal; and

subtracting the first pilot signal from the second pilot signal.

28. A machine-readable medium having stored thereon instructions for controlling a transmission power, which instructions, when executed by a machine, cause the machine to:

perform the method of claim 1;

and

increase the transmission power responsive to the comparing.

29. A machine-readable medium having stored thereon instructions for responding to an admission request, which instructions, when executed by a machine, cause the machine to:

perform the method of claim 1;

and

deny the admission request responsive to the comparing.

30. A machine-readable medium having stored thereon instructions for controlling a data rate, which instructions, when executed by a machine, cause the machine to:

perform the method of claim 1;

and

decrease the data rate responsive to the comparing.

9. A method of calculating a reverse link loading in a wireless communication system, the method comprising:

estimating interference from at least one access terminal not being served by an access point;

measuring a receiver noise in a null time and frequency interval in a guard band; and

comparing the interference to the receiver noise.

16. The wireless communication device of claim 9, wherein the processor is configured to:

divide the interference by the receiver noise.

10. A wireless communication device operable in an orthogonal frequency division multiple access wireless communication system, the wireless communication device comprising:

a processor configured to;

estimate interference from at least one access terminal not being served by the wireless communication device;

measure a receiver noise in a null time and frequency interval, the null time and frequency interval comprising at least one tone of the orthogonal frequency division multiple access wireless communication system; and

compare the interference to the receiver noise; and

a transmitter coupled to the processor and configured to transmit wireless communication signals to a plurality of wireless communication access terminals.

11. The wireless communication device of claim 10, wherein the processor is configured to:

measure a first received power outside a null time and frequency interval.

12. The wireless communication device of claim 11, wherein the processor is configured to:

measure a second received power in the null time and frequency interval.

13. The wireless communication device of claim 10, wherein the processor is configured to:

increase the transmission power responsive to the comparing.

14. The wireless communication device of claim 10, wherein the processor is configured to:

deny the admission request responsive to the comparing.

15. The wireless communication device of claim 10, wherein the processor is configured to:

decrease the data rate responsive to the comparing.

17. A wireless communication device comprising:

a processor configured to;

estimate interference from at least one access terminal not being served by the wireless communication device;

measure a receiver noise in a guard band; and

compare the interference to the receiver noise; and

a transmitter coupled to the processor and configured to transmit wireless communication signals to a plurality of wireless communication access terminals.

18. A wireless communication device operable in an orthogonal frequency division multiple access wireless communication system, the wireless communication device comprising:

a processing means for estimating interference from at least one access terminal not being served by the wireless communication device;

a measuring means for measuring a receiver noise in a null time and frequency interval, the null time and frequency interval comprising at least one tone of the orthogonal frequency division multiple access wireless communication system;

a comparing means for comparing the interference to the receiver noise; and

a transmitting means for transmitting wireless communication signals to a plurality of wireless communication access terminals, the transmitting means being coupled to the processing means.

19. The wireless communication device of claim 18, wherein the processing means further comprises:

a non-null time and frequency measuring means for measuring a first received power outside a null time and frequency interval.

20. The wireless communication device of claim 19, wherein the processing means further comprises:

a null time and frequency measuring means for measuring a second received power in the null time and frequency interval.

21. The wireless communication device of claim 18, wherein the processing means is configured to:

increase the transmission power responsive to the comparing.

22. The wireless communication device of claim 18, wherein the processing means is configured to:

deny the admission request responsive to the comparing.

23. The wireless communication device of claim 18, wherein the processing means is configured to:

decrease the data rate responsive to the comparing.

24. The wireless communication device of claim 18, wherein the processing means is configured to:

divide the interference by the receiver noise.

25. A machine-readable medium having stored thereon instructions, which, when executed by a machine, cause the machine to:

estimate interference from at least one access terminal not being served by an access point;

measure a receiver noise in a null time and frequency interval, the null time and frequency interval comprising at least one tone of an orthogonal frequency division multiple access wireless communication system; and

compare the interference to the receiver noise.

26. The machine-readable medium of claim 25, wherein the measuring comprises:

measuring a first received power outside a null time and frequency interval.

27. The machine-readable medium of claim 26, wherein the estimating interference comprises:

measuring a second received power in the null time and frequency interval.

31. The machine-readable medium of claim 25, wherein the comparing comprises dividing the interference by the receiver noise.

32. A method for assisting a calculation of a reverse link loading in a wireless orthogonal frequency division multiple access communication system, the method comprising:

identifying a null time and frequency interval; and

nulling a wireless transmission during the null time and frequency interval.

33. The method of claim 32, wherein the nulling comprises:

nulling out a tone of a fast fourier transform filter.

34. A mobile wireless communication device comprising:

means for identifying a null time and frequency interval;

means for nulling a wireless transmission during the null time and frequency interval.

35. The mobile wireless communication device of claim 34, further comprising:

means for processing orthogonal frequency division multiple access signals.

36. The mobile wireless communication device of claim 35, further comprising:

means for transmitting orthogonal frequency division multiple access signals.

37. A mobile wireless communication device comprising:

a processor configured to;

identify a null time and frequency interval;

null a wireless transmission during the null time and frequency interval; and

a transmitter coupled to the process, the transmitter configured to transmit the wireless transmission.

38. A machine-readable medium having stored thereon instructions for assisting a calculation of a reverse link loading in a wireless orthogonal frequency division multiple access communication system, which instructions, when executed by a machine, cause the machine to:

identify a null time and frequency interval; and

null a wireless transmission during the null time and frequency interval.