Reduced ping pong occurrence during handover

• US 8,693,439 B2
• Filed: 09/03/2008
• Issued: 04/08/2014
• Est. Priority Date: 09/04/2007
• Status: Expired due to Fees

• Current Assignee: RPX Corporation
• Original Assignee: Nokia Solutions and Networks US LLC (Nokia Corporation)
• Inventors: Vesely, Alexander, Breuer, Volker
• Primary Examiner(s): Sheikh, Ayaz
• Assistant Examiner(s): VU, HOANG-CHUONG Q
• Application Number:
  US12/231,792
• Publication Number:
  US 20090104909A1
• Time in Patent Office: 2,043 Days
• Field of Search: 370331-335, 455436-444
• US Class Current: 370/332
• 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

A method includes handing over a user equipment from a first network access node to a second network access node and, at the second network access node, not considering the first network access node as a handover candidate from the second network access node until at least one of: (a) an amount of time since the hand over from the first network access node exceeds a first threshold amount; (b) there is a change in a channel condition between the user equipment and the first access node that exceeds a second threshold amount.

Claims

1. A method, comprising:

in response to performing a first hand over of a user equipment to a first network access node from a second network access node using a first threshold amount of time and performing a second hand over of the user equipment from the first network access node to the second network access node, creating an updated first threshold amount of time;

in response to a determination that the first network access node is suitable for a third handover procedure, determining, at the second network access node, whether an amount of time since the second hand over exceeds the updated first threshold amount and determining, at the second network access node, whether there is a change in a channel condition between the user equipment and the first network access node that exceeds a second threshold amount;

in response to a determination that the amount of time since the second hand over from the first network access node does not exceed the updated first threshold amount and to a determination that there is not a change in the channel condition between the user equipment and the first network access node that exceeds the second threshold amount, avoiding consideration of the first network access node as a handover candidate from the second network access node; and

performing a wireless network self-optimization process in response to a determination being made that a threshold value 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, by considering the threshold value as an optimized value that is used by a plurality of network access nodes when making user equipment handover decisions.

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

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

4. The method of claim 1, further comprising receiving a measurement report at the second access node that indicates that the first network access node is a suitable handover candidate.

5. The method of claim 1, where creating an updated first threshold amount of time comprises increasing the first threshold amount of time.

6. The method of claim 1, further comprising, in response to performing the first hand over of the user equipment to the first network access node from the second network access node using a value of a difference in signal strength that is measured by the user equipment between the first network access node and the second network access node and performing the second hand over of the user equipment from the first network access node to the second network access node, increasing the value of the difference in signal strength by some certain amount.

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

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

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

in response to performing a first hand over of a user equipment to a first network access node from a second network access node using a first threshold amount of time and performing a second hand over of the user equipment from the first network access node to the second network access node, creating an updated first threshold amount of time;

in response to a determination that the first network access node is suitable for a third handover procedure, determining, at the second network access node, whether an amount of time since the second hand over exceeds the updated first threshold amount and determining, at the second network access node, whether there is a change in a channel condition between the user equipment and the first network access node that exceeds a second threshold amount;

in response to a determination that the amount of time since the second hand over from the first network access node does not exceed the updated first threshold amount and to a determination that there is not a change in the channel condition between the user equipment and the first network access node that exceeds the second threshold amount, avoiding consideration of the first network access node as a handover candidate from the second network access node; and

performing a wireless network self-optimization process in response to a determination being made that a threshold value 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, by considering the threshold value as an optimized value that is used by a plurality of network access nodes when making user equipment handover decisions.

12. The non-transitory computer-readable memory medium of claim 11, where the change in the channel condition is indicated by channel measurements received by the second access node.

13. The non-transitory computer-readable memory medium of claim 11, where the amount of time is indicated by a timer that comprises part of the second network access node.

14. The non-transitory computer-readable memory medium of claim 11, further comprising receiving at the second access node a measurement report that indicates that the first network access node is a suitable handover candidate.

15. The non-transitory computer-readable memory medium of claim 11, where creating an updated first threshold amount of time comprises increasing the first threshold amount of time.

16. The non-transitory computer-readable memory medium of claim 11, further comprising, in response to performing the first hand over of the user equipment to the first network access node from the second network access node using a value of a difference in signal strength that is measured by the user equipment between the first network access node and the second network access node and performing the second hand over of the user equipment from the first network access node to the second network access node, increasing the value of the difference in signal strength by some certain amount.

17. The non-transitory computer-readable memory medium of claim 16, where the certain amount is a value that is configured to the first network access node.

18. The non-transitory computer-readable memory medium of claim 16, where the certain amount is a value that is determined by the first network access node.

19. The non-transitory computer-readable memory medium of claim 16, 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.

20. The non-transitory computer-readable memory medium of claim 11, 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.

21. An apparatus, comprising a processor;

and a memory storing computer program code, the memory and the computer program code configured to, with the processor, cause the apparatus to perform at least the following actions;

in response to performing a first hand over of a user equipment to a first network access node from a second network access node using a first threshold amount of time and performing a second hand over of the user equipment from the first network access node to the second network access node, creating an updated first threshold amount of time;

in response to a determination that the first network access node is suitable for a third handover procedure, determining, at the second network access node, whether an amount of time since the second hand over exceeds the updated first threshold amount and determining, at the second network access node, whether there is a change in a channel condition between the user equipment and the first network access node that exceeds a second threshold amount;

in response to a determination that the amount of time since the second hand over from the first network access node does not exceed the updated first threshold amount and to a determination that there is not a change in the channel condition between the user equipment and the first network access node that exceeds the second threshold amount, avoiding consideration of the first network access node as a handover candidate from the second network access node; and

the memory and the computer program code being configured, with the processor, to cause the apparatus to perform a wireless network self-optimization process in response to a determination being made that a threshold value 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, by considering the threshold value as an optimized value that is used by a plurality of network access nodes when making user equipment handover decisions.

22. The apparatus of claim 21, where the change in the channel condition is indicated by channel measurements received by the second access node via said first interface.

23. The apparatus of claim 21, where the actions further comprise to indicate the amount of time.

24. The apparatus of claim 21, where the actions further comprise 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.

25. The apparatus of claim 21, where creating an updated first threshold amount of time comprises increasing the first threshold amount of time.

26. The apparatus of claim 21, where the actions further comprise, in response to performing the first hand over of the user equipment to the first network access node from the second network access node using a value of a difference in signal strength between the first network access node and the second network access node, and where the user equipment is handed back to the first network access node and performing the second hand over of the user equipment from the first network access node to the second network access node, to increase the value of the difference in signal strength by some certain amount.

27. The apparatus of claim 26, where the certain amount is a value that is configured to the first network access node.

28. The apparatus of claim 26, where the certain amount is a value that is determined by said controller of said first access node.

29. The apparatus of claim 21, 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.

30. The apparatus of claim 21, 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.

31. The apparatus of claim 21, embodied at least partially as an integrated circuit.

32. A method, comprising:

handing over a user equipment from a first network access node to a second network access node based on a difference in signal strength that is received in a report from the user equipment exceeding a threshold value, the difference in signal strength being between the first network access node and the second network access node;

receiving a hand over of the same user equipment at the first network access node from the second network access node;

in response to handing over and then receiving the hand over of the same user equipment, at the first network access node, increasing the threshold value by some certain amount so that the user equipment is avoided from being handed over to the second access node again unless the difference in the signal strength between the first network access node and the second network access node is equal to or exceeds the increased value,

where an initial value of the certain amount is configured to the first network access node or

where the initial value of the certain amount is determined by a controller of the first network access node; and

performing a wireless network self-optimization process in response to a determination being made that the threshold value 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, by considering the threshold value as an optimized value that is used by a plurality of network access nodes when making user equipment handover decisions.

33. The method of claim 32, where the threshold value is incrementally increased until the user equipment ceases to ping pong between the first network access node and the second network access node.