BATTERY EFFICIENT METHOD TO SEARCH FOR PREFERRED FEMTOCELL

• US 20100035601A1
• Filed: 07/31/2009
• Published: 02/11/2010
• Est. Priority Date: 08/05/2008
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Pica, Fracesco, Deshpande, Manoj M., Nanda, Sanjiv, Yavuz, Mehmet, Chen, Jen Mei
• Granted Patent: US 9,386,431 B2
• Time in Patent Office: Days
• US Class Current: 455/423
• CPC Class Codes: H04W 4/20 Services signaling; Auxiliary data signalling, i.e. transmitting data via a non-traffic channel
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

Mobile user equipment (MUE) can be enabled to search for and camp on a preferred node, such as a home base node (HBN), in a battery-efficient manner even when currently camped on another node, such as a macro base node (MBN). When the MBN provides good channel quality, slow rate background intra- and inter-frequency searches can discover the preferred HBN that would otherwise not be discovered or would consume excessive power with continual searching. When channel quality is fair, slow rate background inter-frequency searches can result in timely switching to the preferred HBN. Location hints that indicate proximity of the preferred HBN can be used to trigger slow rate background searches. Neighboring cell searching of neighbor cell listing (NCL) when in channel quality is fair or poor are maintained to prepare for call reselections to available node.

Claims

1. A method for reliable and power-efficient discovery of a preferred node, comprising:

employing a processor executing computer executable instructions stored on a computer readable storage medium to implement following acts;

measuring signal quality of a wireless channel transmitted by a serving node;

determining the signal quality to be above a threshold, wherein being below the threshold indicates a need to prepare for cell reselection to a neighboring node;

periodically performing measurements for neighboring nodes; and

periodically performing measurements for a preferred node at a slower repetition rate than the measurements for neighboring nodes in response to the signal quality being above the threshold.

2. The method of claim 1, further comprising determining the signal quality to indicate a good channel above the threshold that would otherwise trigger intra-frequency searching.

3. The method of claim 1, further comprising determining the signal quality to indicate a fair channel above the threshold that would otherwise trigger inter-frequency searching.

4. The method of claim 1, further comprising performing measurements for a preferred closed subscription node.

5. The method of claim 1, further comprising performing measurements for a femtocell.

6. The method of claim 5, further comprising performing measurements for a home base node.

7. The method of claim 1, further comprising enabling the slower rate repetition measurements for the preferred node in response to a determination that user equipment has predefined a preferred node.

8. The method of claim 1, further comprising:

performing synchronization and measurement for transmissions from the serving node during each discontinuous reception (DRX) cycle; and

performing slower repetition rate at multiples of the discontinuous reception (DRX) cycle.

9. The method of claim 1, further comprising:

accessing information indicative of a location of a mobile device;

determining proximity to the preferred node; and

enabling slower repetition rate measurements for the preferred node in response to the proximity being closer than a coverage area threshold.

10. The method of claim 9, further comprising:

determining location based upon a positioning system; and

accessing geographic location for the preferred node.

11. The method of claim 9, further comprising associating a location of the preferred node as proximate to a coverage area of a macro base node.

12. The method of claim 9, further comprising:

associating a broadcast beacon with the preferred node; and

initiating periodic measurements for the preferred node at the slower repetition rate in response to detecting the broadcast beacon.

13. The method of claim 1, further comprising receiving broadcast information from a node identifying neighboring nodes.

14. The method of claim 1, further comprising receiving self-identifying broadcast information from the preferred node.

15. The method of claim 1, further comprising:

receiving a scrambling code by broadcast for demodulating a synchronization signal from a node; and

periodically performing measurements for the preferred node using the scrambling code.

16. The method of claim 15, further comprising receiving a plurality of scrambling codes for respective neighboring nodes from a serving node.

17. The method of claim 15, further comprising receiving the scrambling code from a non-serving preferred node that transmits using the scrambling code.

18. The method of claim 1, further comprising discontinuing periodically performing measurements for the preferred node at the slower repetition rate than the measurements for neighboring nodes in response to camping on the preferred node.

19. A computer program product for reliable and power-efficient discovery of a preferred node, comprising:

at least one computer readable storage medium storing computer executable instructions that, when executed by at least one processor, implement components comprising;

a first set of instructions for causing a computer to measure signal quality of a wireless channel transmitted by a serving node;

a second set of instructions for causing the computer to determine the signal quality to be above a threshold, wherein being below the threshold indicates a need to prepare for cell reselection to a neighboring node;

a third set of instructions for causing the computer to periodically perform measurements for neighboring nodes; and

a fourth set of instructions for causing the computer to periodically perform measurements for a preferred node at a slower repetition rate than the measurements for neighboring nodes in response to the signal quality being above the threshold.

20. An apparatus for reliable and power-efficient discovery of a preferred node, comprising:

at least one processor;

at least one computer readable storage medium storing computer executable instructions that, when executed by the at least one processor, implement components comprising;

means for measuring signal quality of a wireless channel transmitted by a serving node;

means for determining the signal quality to be above a threshold, wherein being below the threshold indicates a need to prepare for call reselection to a neighboring node;

means for periodically performing measurements for neighboring nodes; and

means for periodically performing measurements for a preferred node at a slower repetition rate than the measurements for neighboring nodes in response to the signal quality being above the threshold.

21. An apparatus for reliable and power-efficient discovery of a preferred node, comprising:

a receiver for measuring signal quality of a wireless channel transmitted by a serving node; and

a computing platform for,

determining the signal quality to be above a threshold, wherein being below the threshold indicates a need to prepare for cell reselection to a neighboring node,

causing the receiver to periodically perform measurements for neighboring nodes, and

causing the receiver to periodically perform measurements for a preferred node at a slower repetition rate than the measurements for neighboring nodes in response to the signal quality being above the threshold.

22. The apparatus of claim 21, wherein the computing platform is further for determining the signal quality to indicate a good channel above the threshold that would otherwise trigger intra-frequency searching.

23. The apparatus of claim 21, wherein the computing platform is further for determining the signal quality to indicate a fair channel above the threshold that would otherwise trigger inter-frequency searching.

24. The apparatus of claim 21, wherein the receiver is further for performing measurements for a preferred closed subscription node.

25. The apparatus of claim 21, wherein the receiver is further for performing measurements for a femtocell.

26. The apparatus of claim 25, wherein the receiver is further for performing measurements for a home base node.

27. The apparatus of claim 21, wherein the computing platform is further for enabling the slower rate repetition measurements for the preferred node in response to a determination that user equipment has predefined a preferred node.

28. The apparatus of claim 21, wherein the computing platform is further for performing synchronization and measurement for transmissions from the serving node during each discontinuous reception (DRX) cycle, and for performing slower repetition rate at multiples of the discontinuous reception (DRX) cycle.

29. The apparatus of claim 21, wherein the computing platform is further for accessing information indicative of a location of a mobile device, for determining proximity to the preferred node, and for enabling slower repetition rate measurements for the preferred node in response to the proximity being closer than a coverage area threshold.

30. The apparatus of claim 29, wherein the computing platform is further for determining location based upon a positioning system, and for accessing geographic location for the preferred node.

31. The apparatus of claim 29, wherein the computing platform is further for associating a location of the preferred node as proximate to a coverage area of a macro base node.

32. The apparatus of claim 29, wherein the computing platform is further for associating a broadcast beacon with the preferred node, and for initiating periodic measurements for the preferred node at the slower repetition rate in response to the receiver detecting the broadcast beacon.

33. The apparatus of claim 21, wherein the receiver is further for receiving broadcast information from a node identifying neighboring nodes.

34. The apparatus of claim 21, wherein the receiver is further for receiving self-identifying broadcast information from the preferred node.

35. The apparatus of claim 21, wherein the receiver is further for receiving a scrambling code by broadcast for demodulating a synchronization signal from a node, and for periodically performing measurements for the preferred node using the scrambling code.

36. The apparatus of claim 35, wherein the receiver is further for receiving a plurality of scrambling codes for respective neighboring nodes from a serving node.

37. The apparatus of claim 35, wherein the receiver is further for receiving the scrambling code from a non-serving preferred node that transmits using the scrambling code.

38. The apparatus of claim 21, wherein the computing platform is further for discontinuing periodically performing measurements for the preferred node at the slower repetition rate than the measurements for neighboring nodes in response to camping on the preferred node.

39. A method for facilitating reliable and power-efficient discovery of a preferred node, comprising:

employing a processor executing computer executable instructions stored on a computer readable storage medium to implement following acts;

serving a mobile device as a serving node by transmitting and receiving wireless data packet communication; and

facilitating discovery by the mobile device of a preferred node by broadcasting a scrambling code used by the preferred node to the mobile device,

wherein the mobile device periodically performs measurements for a preferred node at a slower repetition rate than the measurements for neighboring nodes in response to the signal quality being above the threshold.

40. The method of claim 39, further comprising:

maintaining a neighbor list for nodes within a coverage area, wherein the preferred node is one of the nodes; and

broadcasting scrambling codes for the nodes within the coverage area.

41. The method of claim 39, further comprising broadcasting the scrambling code by the preferred node for facilitating discovery by the mobile device.

42. The method of claim 39, further comprising scheduling a served mobile device for a discontinuous reception (DRX) cycle for performing synchronization and measurement for transmissions from the serving node and neighboring nodes and for periodically performing measurements for the preferred node at a slower repetition rate than the measurements for neighboring nodes in response to the signal quality being above the threshold.

43. The method of claim 39, further comprising transmitting information related to location enabling the mobile device to selectively perform measurements for the preferred node at the slower repetition rate.

44. A computer program product for facilitating reliable and power-efficient discovery of a preferred node, comprising:

at least one processor;

at least one computer readable storage medium storing computer executable instructions that, when executed by the at least one processor, implement components comprising;

a first set of instructions for causing a computer to serve a mobile device as a serving node by transmitting and receiving wireless data packet communication; and

a second set of instructions for causing the computer to facilitate discovery by the mobile device of a preferred node by broadcasting a scrambling code used by the preferred node to the mobile device,

wherein the mobile device periodically performs measurements for a preferred node at a slower repetition rate than the measurements for neighboring nodes in response to the signal quality being above the threshold.

45. An apparatus for facilitating reliable and power-efficient discovery of a preferred node, comprising:

at least one computer readable storage medium storing computer executable instructions that, when executed by at least one processor, implement components comprising;

means for serving a mobile device as a serving node by transmitting and receiving wireless data packet communication; and

means for facilitating discovery by the mobile device of a preferred node by broadcasting a scrambling code used by the preferred node to the mobile device,

wherein the mobile device periodically performs measurements for a preferred node at a slower repetition rate than the measurements for neighboring nodes in response to the signal quality being above the threshold.

46. An apparatus for facilitating reliable and power-efficient discovery of a preferred node, comprising:

a receiver for receiving wireless data packet communication service from a mobile device as a serving node;

a computing platform for accessing a scrambling code used by a preferred node; and

a transmitter for broadcasting the scrambling code to the mobile device facilitating discovery by the mobile device of a preferred node,

wherein the mobile device periodically performs measurements for a preferred node at a slower repetition rate than the measurements for neighboring nodes in response to the signal quality being above the threshold.

47. The apparatus of claim 46, wherein the computing platform is further for maintaining a neighbor list for nodes within a coverage area, wherein the preferred node is one of the nodes;

and

the transmitter is further for broadcasting scrambling codes for the nodes within the coverage area.

48. The apparatus of claim 46, wherein the transmitter is further for broadcasting the scrambling code by the preferred node for facilitating discovery by the mobile device.

49. The apparatus of claim 46, wherein the computing platform is further for scheduling a served mobile device for a discontinuous reception (DRX) cycle for performing synchronization and measurement for transmissions from the serving node and neighboring nodes and for periodically performing measurements for the preferred node at a slower repetition rate than the measurements for neighboring nodes in response to the signal quality being above the threshold.

50. The apparatus of claim 46, wherein the transmitter is further for transmitting information related to location enabling the mobile device to selectively perform measurements for the preferred node at the slower repetition rate.