Active set management with hotspot carriers

• US 8,175,594 B2
• Filed: 10/20/2009
• Issued: 05/08/2012
• Est. Priority Date: 10/24/2008
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Attar, Rashid Ahmed Akbar, Black, Peter John, Ghosh, Donna, Lott, Christopher Gerard
• Primary Examiner(s): Nguyen, Tu X
• Application Number:
  US12/582,557
• Publication Number:
  US 20100105336A1
• Time in Patent Office: 931 Days
• Field of Search: 455/436, 455/69, 455/522, 455/432.1, 455/422.1, 455/435.2, 455/11.3, 455/115.1
• US Class Current: 455/432.1
• CPC Class Codes: H04W 72/02 Selection of wireless resources by user or terminal
• CPC Class Codes: H04W 72/541 using the level of interference

Abstract

Techniques for managing communications in a cellular network are disclosed. The cellular network can include one or more sectors in which hotspot carriers are deployed. The hotspot carriers can be available to mobile devices beyond sector boundaries defined by the signal strength of ubiquitous carriers. A mobile device can measure a signal strength of a candidate hotspot carrier and estimate a reverse link mobile device transmit power level for communicating on the hotspot carrier. The mobile device may determine whether to add, remove, or maintain the hotspot carrier in its active set based on the estimated transmit power level so as to limit interference to the reverse link of non-hotspot sectors.

Claims

1. A method of communicating in a cellular network, the method comprising:

receiving a candidate carrier from a first base station at a mobile device;

determining at the mobile device a first reverse link transmit power level associated with the candidate carrier based on a pilot power level of the received candidate carrier;

determining at the mobile device a difference between the first reverse link transmit power level and a second reverse link transmit power level corresponding to a second carrier used by the mobile device to communicate with a second base station; and

updating at the mobile device a set of carriers available to the mobile device for communicating on the cellular network based on the difference between the first reverse link transmit power level and the second reverse link transmit power level.

2. The method of claim 1, wherein determining the first power level comprises estimating the transmit power level for reverse link communication with the first base station on the candidate carrier.

3. The method of claim 2, wherein determining the difference further comprises comparing the estimated first reverse link transmit power level for reverse link communication with the second reverse link transmit power level for reverse link communication with the second base station on the second carrier.

4. The method of claim 1, wherein the updating comprises adding information about the candidate carrier to the set of carriers in response to the difference being less than a predetermined value.

5. The method of claim 1, wherein the updating comprises removing information about the candidate carrier from the set of carriers in response to the difference being greater than a predetermined value.

6. The method of claim 1, wherein receiving the candidate carrier further comprises determining a power level of a forward link pilot from the first base station.

7. The method of claim 6, wherein updating the set of carriers comprises adding information about the candidate carrier in response to the difference being less than a predetermined value and the power level of the forward link pilot from the first base station exceeding a second threshold.

8. The method of claim 6, wherein updating the set of carriers comprises removing information about the candidate carrier from the set of carriers in response to the difference exceeding a predetermined value or the power level of the forward link pilot from the first base station being below a second threshold.

9. The method of claim 1, wherein the set of carriers is updated in response to the difference exceeding a predetermined value based on a frequency spacing of the cellular network.

10. The method of claim 1, wherein the set of carriers includes information relating to at least one base station and frequency pair.

11. The method of claim 1, wherein the second base station transmits only on one or more frequencies other than frequencies of the candidate carrier.

12. The method of claim 1, wherein the mobile device is configured to process signals having a format as specified by TIA-856 (Telecommunications Industry Association) standards.

13. The method of claim 1, wherein the candidate carrier comprises a hotspot carrier or a partial overlay carrier of the cellular network.

14. The method of claim 1, wherein the first power level comprises an average of an estimated transmit power for reverse link communication with the first base station and the second power level comprises an average of the transmit power for reverse link communication with the second base station.

15. The method of claim 14 wherein determining the difference comprises subtracting the first power level from the second power level or subtracting the second power level from the first power level.

16. The method of claim 14, further comprising filtering the first power level to determine the average of the estimated transmit power for reverse link communication with the first base station and filtering the second power level to determine the average of the transmit power for reverse link communication with the second base station.

17. A mobile device operative for wireless communication on a cellular network, the mobile device comprising:

means for receiving a candidate carrier from a first base station;

means for determining a first reverse link transmit power level associated with the candidate carrier based on a pilot power level of the received candidate carrier;

means for determining a difference between the first reverse link transmit power level and a second reverse link transmit power level corresponding to a second carrier used by the mobile device to communicate with a second base station; and

means for updating a set of carriers available to the mobile device for communicating on the cellular network based on the difference between the first reverse link transmit power level and the second reverse link transmit power level.

18. The mobile device of claim 17, wherein the means for determining the first power level comprises means for estimating the first reverse link transmit power level for reverse link communications with the first base station.

19. The mobile device of claim 18, further comprising means for comparing the estimated first reverse link transmit power level to the second reverse link transmit power level for reverse link communications with the second base station.

20. The mobile device of claim 17, wherein the means for updating comprises means for adding information about the candidate carrier to the set of carriers in response to the difference being less than a predetermined value.

21. The mobile device of claim 17, wherein the means for updating comprises means for removing information about the candidate carrier from the set of carriers in response to the difference being greater than a predetermined value.

22. The mobile device of claim 17, wherein the means for receiving the candidate signal further comprises means for determining a power level of a forward link pilot from the first base station.

23. The mobile device of claim 17, wherein the means for updating the set of carriers comprises means for adding information about the candidate carrier in response to the difference being less than the predetermined value and the power level of the forward link pilot from the first base station exceeding a second threshold.

24. The mobile device of claim 17, wherein the means for updating the set of carriers comprises means for removing information about the candidate carrier from the set of carriers in response to the difference exceeding the predetermined value or the power level of the forward link pilot from the first base station being below a second threshold.

25. The mobile device of claim 17, further comprising means for transmitting to the first base station on a reverse link carrier in response to the updating the set of carriers.

26. The mobile device of claim 17, wherein mobile device is configured to process signals having a format specified by TIA-856 (Telecommunications Industry Association) standards.

27. The mobile device of claim 17, wherein the candidate signal comprises a hotspot carrier or a partial overlay carrier in the cellular network.

28. The mobile device of claim 17, wherein the first power level comprises an average of an estimated transmit power for reverse link communication with the first base station and the second power level comprises an average of the transmit power for reverse link communication with the second base station.

29. The mobile device of claim 28, wherein the means for determining the difference comprise means for subtracting the first power level from the second power level or means for subtracting the second power level from the first power level.

30. The mobile device of claim 28, further comprising means for filtering the first power level to determine the average of the estimated transmit power for reverse link communication with the first base station, and means for filtering the second power level to determine the average of the transmit power for reverse link communication with the second base station.

31. A computer program product comprising:

a computer readable medium comprising instructions configured to cause a computer to;

receive a candidate carrier from a first base station at the mobile device;

determine a first reverse link transmit power level associated with the candidate carrier based on a pilot power level of the received candidate carrier;

determine a difference between the first reverse link transmit power level and a second reverse link transmit power level corresponding to a second carrier used by the mobile device to communicate with a second base station; and

update a set of carriers available to the mobile device for communicating on the cellular network based on the difference between the first reverse link transmit power level and the second reverse link transmit power level.

32. A mobile device comprising:

a receiver configured to receive forward link signals associated with base stations in a cellular network;

a transmitter configured to send reverse link signals corresponding to the forward link signals;

a processor coupled to the receiver and the transmitter, the processor configured to decode the forward link signals and to send data on the corresponding reverse link signals based on an active carrier set;

a memory coupled to the processor and configured to store the active carrier set comprising information about carriers available to the mobile device for communicating in the cellular network,

wherein the processor is further configured to estimate a transmit power level of a reverse link signal corresponding to a candidate forward link signal based on a pilot power level of the candidate forward link signal and to update the active carrier set based on a difference between the estimated reverse link transmit power level corresponding to the candidate forward link signal and a reverse link transmit power level of a reference carrier in the active set.

33. A method of wireless communication performed by a mobile device, the method comprising:

communicating with a first base station on a first carrier;

detecting availability of a hotspot carrier;

measuring a pilot power level of the hotspot carrier;

estimating a reverse link transmit power associated with the hotspot carrier based on the pilot power level;

adding information relating to the hotspot carrier to an active set of the mobile device in response to the pilot power level of the hotspot carrier exceeding a first threshold and a difference between the estimated reverse link transmit power and a reverse link transmit power for communicating with the first base station being below a second threshold; and

removing information relating to the hotspot carrier from the active set of the mobile device in response to the pilot power level of the hotspot carrier being less than the first predetermined threshold value or the difference between the estimated reverse link transmit power and the reverse link transmit power for communicating with the first base station exceeding the second threshold.