REDUCED PING PONG OCCURRENCE DURING HANDOVER

• US 20090104909A1
• Filed: 09/03/2008
• Published: 04/23/2009
• Est. Priority Date: 09/04/2007
• Status: Active Grant

• Current Assignee: RPX Corporation
• Original Assignee: Nokia Solutions and Networks US LLC (Nokia Corporation)
• Inventors: Breuer, Volker, Vesely, Alexander
• Granted Patent: US 8,693,439 B2
• Time in Patent Office: Days
• US Class Current: 455/436
• CPC Class Codes: H04W 36/00837 Determination of triggering parameters for hand-off
• CPC Class Codes: H04W 36/008375 based on historical data
• CPC Class Codes: H04W 36/0085 Hand-off measurements
• CPC Class Codes: H04W 36/08 Reselecting an access point

Abstract

Disclosed is a method, computer-readable memory medium and apparatus configured to reduce an occurrence of handover ping ponging of user equipment between network access nodes.

Claims

1. A method, comprising:

handing over a user equipment from a first network access node to a second network access node; and

not considering the first network access node as a handover candidate from the second network access node for some period of time unless there is indicated a change in channel conditions that exceed a threshold in one or both of time and an amount of change.

2. The method of claim 1, where the change in channel conditions is indicated by channel measurements received by the second access node.

3. The method of claim 1, where the period of time is indicated by a timer that comprises part of the second network access node.

4. The method of claim 1, further comprising receiving a measurement report that indicates that the first network access node is a suitable handover candidate, and not considering the first network access node as a handover candidate from the second network access node until a timer of the second network access node expires, where the timer is started in response to the handover from the first network access node to the second network access node.

5. The method of claim 4, where an amount of time that the timer runs is variable, and is increased in response to an occurrence of a ping pong handover occurring back to the first network access node.

6. The method of claim 1, where for a case where the user equipment was handed over to the second network access node based on some amount of difference of measured signal strength between the first network access node and the second network access node exceeding a threshold, and where the user equipment is handed back to the first network access node, increasing the threshold for the user equipment by some certain amount.

7. The method of claim 6, where the certain amount is a value that is configured to the network access node.

8. The method of claim 6, where the certain amount is a value that is determined by the network access node.

9. The method of claim 6, where a value of the certain amount is incrementally increased until the user equipment ceases to ping pong between the first network access node and the second network access node.

10. The method of claim 9 further comprising, in response to the value of the certain amount where the user equipment ceases to ping pong between the first network access node and the second network access node being found to be approximately the same value for a plurality of user equipment, considering the value as an optimized value that is used by a plurality of network access nodes when making user equipment handover decisions.

11. The method of claim 1, where the first network access node is provided by a first vendor, and where the second network access node is provided by a second vendor.

12. A computer-readable memory medium that stores computer program instructions, where execution of the instructions results in performance of operations comprising:

handing over a user equipment from a first network access node to a second network access node; and

not considering the first network access node as a handover candidate from the second network access node for some period of time unless there is indicated a change in channel conditions that exceed a threshold in one or both of time and an amount of change.

13. The computer-readable memory medium of claim 12, where the change in channel conditions is indicated by channel measurements received by the second access node.

14. The computer-readable memory medium of claim 12, where the period of time is indicated by a timer that comprises part of the second network access node.

15. The computer-readable memory medium of claim 12, further comprising an operation of receiving a measurement report that indicates that the first network access node is a suitable handover candidate, and not considering the first network access node as a handover candidate from the second network access node until a timer of the second network access node expires, where the timer is started in response to the handover from the first network access node to the second network access node.

16. The computer-readable memory medium of claim 15, where an amount of time that the timer runs is variable, and is increased in response to an occurrence of a ping pong handover occurring back to the first network access node.

17. The computer-readable memory medium of claim 12, where for a case where the user equipment was handed over to the second network access node based on some amount of difference of measured signal strength between the first network access node and the second network access node exceeding a threshold, and where the user equipment is handed back to the first network access node, increasing the threshold for the user equipment by some certain amount.

18. The computer-readable memory medium of claim 17, where the certain amount is a value that is configured to the network access node.

19. The computer-readable memory medium of claim 17, where the certain amount is a value that is determined by the network access node.

20. The computer-readable memory medium of claim 17, where a value of the certain amount is incrementally increased until the user equipment ceases to ping pong between the first network access node and the second network access node.

21. The computer-readable memory medium of claim 12, further comprising an operation of, in response to the value of the certain amount where the user equipment ceases to ping pong between the first network access node and the second network access node being found to be approximately the same value for a plurality of user equipment, considering the value as an optimized value that is used by a plurality of network access nodes when making user equipment handover decisions.

22. The computer-readable memory medium of claim 12, where the first network access node is provided by a first vendor, and where the second network access node is provided by a second vendor.

23. An apparatus, comprising:

a first interface configured to conduct bidirectional wireless communication with a user equipment;

a second interface configured to conduct bidirectional communication with a first network access node to hand over the user equipment from the first network access node to a second network access node; and

a controller configured to not consider the first network access node as a handover candidate from the second network access node for some period of time unless there is indicated a change in channel conditions that exceed a threshold in one or both of time and an amount of change.

24. The apparatus of claim 23, where the change in channel conditions is indicated by channel measurements received by the second access node via said first interface.

25. The apparatus of claim 23, further comprising a timer configured to indicate the period of time.

26. The apparatus of claim 23 and further comprising a timer, where said controller is further configured to respond to a measurement report that is received via said first interface, the measurement report indicating that the first network access node is a suitable handover candidate, to not consider the first network access node as a handover candidate from the second network access node until said timer expires, where said timer is started in response to the handover of the user equipment from the first network access node to the second network access node.

27. The apparatus of claim 26, where an amount of time that the timer runs is variable, and is increased in response to an occurrence of a ping pong handover occurring back to the first network access node.

28. The apparatus of claim 23, where for a case where the user equipment was handed over to the second network access node based on some amount of difference of measured signal strength between the first network access node and the second network access node exceeding a threshold, and where the user equipment is handed back to the first network access node, said controller is further configured to increase the threshold for the user equipment by some certain amount.

29. The apparatus of claim 28, where the certain amount is a value that is configured to the second network access node.

30. The apparatus of claim 28, where the certain amount is a value that is determined by said controller.

31. The apparatus of claim 23, where a value of the certain amount is incrementally increased until the user equipment ceases to ping pong between the first network access node and the second network access node.

32. The apparatus of claim 31, further comprising, in response to a determination being made that the value of the certain amount where the user equipment ceases to ping pong between the first network access node and the second network access node is approximately the same value for a plurality of user equipment, considering the value as an optimized value that is used by a plurality of network access nodes when making user equipment handover decisions.

33. The apparatus of claim 23, where the first network access node is provided by a first vendor, and where the second network access node is provided by a second vendor.

34. The apparatus of claim 23, embodied at least partially as an integrated circuit.

35. An apparatus, comprising:

means for handing over a user equipment from a first network access node to a second network access node;

means for starting a timer means to run for a predetermined period of time in response to operation of the means for handing over;

means for considering the first network access node as a handover candidate from the second network access node only after said timer means expires; and

means for adjusting the predetermined period of time in order to reduce an occurrence of ping ponging of the user equipment between the first network access node and the second network access node.

36. The apparatus of claim 35, where said considering means is further configured to consider the first access node as a handover candidate, before expiration of said timer means in response to a change in channel conditions that exceed at least one threshold amount.

37. The apparatus of claim 35, further comprising means, responsive to the user equipment being handed over to the second network access node based on some amount of difference of measured signal strength between the first network access node and the second network access node exceeding a threshold, and to the user equipment being handed back to the first network access node, for increasing the threshold.