Method for detecting and reducing ping-pong handover effect of cellular network

• US 20060003768A1
• Filed: 06/30/2005
• Published: 01/05/2006
• Est. Priority Date: 07/02/2004
• Status: Active Grant

• Current Assignee: Ground Hog Inc.
• Original Assignee: Groundhog Technologies, Inc.
• Inventors: Chiou, Ta-gang
• Granted Patent: US 7,263,358 B2
• Time in Patent Office: Days
• US Class Current: 455/436
• CPC Class Codes: H04W 36/008375 based on historical data

Abstract

A method for detecting and reducing ping-pong handover effect of a cellular network is disclosed. The method provides a systematic way to determine which cell pairs of the network have high probability of suffering from the ping-pong handover effect. The method comprises collecting network traffic statistic data of multiple items, wherein each of the items corresponds to a state change of multiple mobile units within cells of the network; determining whether a plurality of criteria are met according to the network traffic statistic data; and detecting the ping-pong effect between the cells according to the result of the determining step. The method also comprises changing a handover parameter for the cells with the ping-pong handover effect.

Claims

1. A method for detecting ping-pong handover effect of a cellular network, comprising:

collecting network traffic statistic data of a plurality of items, wherein each of the items corresponds to a state change of a plurality of mobile units within cells of the cellular network;

determining whether a plurality of criteria are met according to the network traffic statistic data; and

detecting the ping-pong handover effect between the cells according to a result of the determining step.

2. The method according to claim 1, wherein the items include handover between a first cell and a second cell of the cells.

3. The method according to claim 2, wherein the items further include at least one of mobile terminating call (MTC) and mobile originating call (MOC) within the first and second cells.

4. The method according to claim 3, wherein the criteria comprise comparing a first parameter with a first threshold, wherein the first parameter is defined according to the handover from the first cell to the second cell and at least one of the MTC and MOC within one of the first and second cells.

5. The method according to claim 4, wherein the criteria further comprise comparing the handover from the first cell to the second cell with a second threshold.

6. The method according to claim 5, wherein the criteria further comprise the handover from the first cell to the second cell is symmetric to that from the second cell to the first cell, and the first parameter is symmetric to a first reverse parameter defined according to the handover from the second cell to the first cell and at least one of the MTC and MOC within one of the first and second cells.

7. The method according to claim 2, wherein the cells of the cellular network are grouped into a plurality of location areas, and the items further include location area update of each cell and handover between the cells.

8. The method according to claim 7, wherein the criteria comprise comparing a second parameter with a third threshold, wherein the second parameter is defined according to signal movements from the first cell to the second cell in active mode and in idle mode.

9. The method according to claim 8, wherein the criteria further comprise the second parameter is symmetric to a second reverse parameter defined according to signal movements from the second cell to the first cell in active mode and in idle mode.

10. The method according to claim 1, wherein the items include non-directional handover between a first cell and neighboring cells thereof, and at least one of MTC and MOC within the first cell.

11. The method according to claim 10, wherein the criteria comprise:

(1) comparing the non-directional handover with a fourth threshold; and

(2) comparing a third parameter with a fifth threshold, wherein the third parameter is defined according to the non-directional handover and at least one of the MTC and MOC within the first cell.

12. The method according to claim 2, wherein the items further include handover back between the first and second cells.

13. The method according to claim 12, wherein the criteria comprise comparing a fourth parameter with a seventh threshold, wherein the fourth parameter is defined according to the handover and the handover back between the first and second cells.

14. The method according to claim 13, wherein the criteria comprise comparing the handover back between the first and second cells with a sixth threshold.

15. The method according to claim 1, wherein the criteria comprise comparing signal fluctuation caused by environment of the cells with a level.

16. The method according to claim 1, wherein each of the criteria has a related parameter which has a corresponding value for each of a plurality of cell pairs, wherein the corresponding value is determined according to the network traffic statistic data.

17. The method according to claim 16, wherein the detecting step comprises:

generating a weighting score for each qualified cell pair of each of the criteria according to the corresponding value of the qualified cell pair;

comparing a sum of the weighting scores of each qualified cell pair with a threshold; and

deciding whether the qualified cell pair has the ping-pong handover effect according to a result of the comparing step.

18. A method for reducing ping-pong handover effect of a cellular network, comprising:

collecting network traffic statistic data of a plurality of items, wherein each of the items corresponds to a state change of a plurality of mobile units within cells of the cellular network;

determining whether a plurality of criteria are met according to the network traffic statistic data;

detecting the ping-pong handover effect between the cells according to a result of the determining step; and

changing a handover parameter for the cells with the ping-pong handover effect.

19. The method according to claim 18, wherein the handover parameter is handover hysteresis.

20. The method according to claim 18, wherein the handover parameter is handover window timer.

21. The method according to claim 18, wherein the change of the handover parameter does not cause negative effect on the cellular network.

22. The method according to claim 21, wherein the handover parameter is not higher than an allowable threshold.