Method and apparatus for optimizing UE identification

1. A method in a base station, BS, of a cellular radio system for optimizing criteria of identifying a user equipment, UE, as in a first UE group or a second UE group, wherein a speed of any UE in the first UE group is higher than a speed of any UE in the second UE group, the method comprising:

detecting one or more handover failure events of at least one of the first UE group and the second UE group;

determining whether there is any UE misidentified in the first or second UE group based on the one or more handover failure events; and

in response to determining that there is a UE misidentified in the first or second UE group, adjusting at least one of the criteria of identifying a UE as in the first UE group and the criteria of identifying a UE as in the second UE group.

2. The method of claim 1 , wherein after said detecting, the method further comprises:

in response that a predefined number of too-early or too-late handover events of the first UE group or the second UE group are detected, modifying a handover triggering condition for a respective UE group; and

wherein said determining comprises:

in response that, after a predetermined number of said modifying or after a predetermined period of time of said modifying, the handover triggering condition for the first UE group or the second UE group fails to reach a steady state where the number of detected handover failure events in a respective UE group is below a predefined threshold, determining that a UE is misidentified in the respective UE group.

3. The method of claim 2 , wherein said adjusting comprises:

in response to determining that a UE is misidentified in the first UE group, upgrading the criteria of identifying a UE as in the first UE group and/or degrading the criteria of identifying a UE as in the second UE group; or

in response to determining that a UE is misidentified in the second UE group, degrading the criteria of identifying a UE as in the first UE group and/or upgrading the criteria of identifying a UE as in the second UE group.

4. The method of claim 3 , wherein the criteria of identifying a UE as in the first UE group or the second UE group are based on Doppler Frequency-Offset Estimation, FOE, wherein a UE is identified as in the first UE group if a Doppler-FOE related parameter of the UE is higher than a third threshold, and a UE is identified as in the second UE group if the Doppler-FOE related parameter is lower than a fourth threshold; and

wherein said degrading the criteria of identifying a UE as in the first UE group comprises decreasing the third threshold, said upgrading the criteria of identifying a UE as in the second UE group comprises decreasing the fourth threshold, said upgrading the criteria of identifying a UE as in the first UE group comprises increasing the third threshold, and said degrading the criteria of identifying a UE as in the second UE group comprises increasing the fourth threshold.

5. The method of claim 1 , wherein said determining comprises:

in response that a predefined number of too-early handover events of the first UE group are detected where a difference of signal quality between a target cell and a source cell associated with a respective too-early handover event is larger than a first threshold, determining that a UE is misidentified in the first UE group; or

in response that a predefined number of too-late handover events of the second UE group are detected where a difference of signal quality between a target cell and a source cell associated with a respective too-late handover event is smaller than a second threshold, determining that a UE is misidentified in the second UE group.

6. The method of claim 1 , wherein said determining comprises:

in response that a predefined number of too-early handover events are detected, determining that a UE is misidentified in the first UE group; or

in response that a predefined number of too-late handover events are detected, determining that a UE is misidentified in the second UE group.

7. A base station, BS, of a cellular radio system for optimizing criteria of identifying a user equipment, UE, as in a first UE group or a second UE group, wherein a speed of any UE in the first UE group is higher than a speed of any UE in the second UE group, the base station comprising:

a detecting module, configured to detect one or more handover failure events of at least one of the first UE group and the second UE group;

a determining module, configured to determine whether there is any UE misidentified in the first or second UE group based on the one or more handover failure events; and

an adjusting module, configured to, in response to determining that there is a UE misidentified in the first or second UE group, adjust at least one of the criteria of identifying a UE as in the first UE group and the criteria of identifying a UE as in the second UE group.

8. The base station of claim 7 , wherein the base station further comprises:

a modifying module, configured to, in response that a predefined number of too-early or too-late handover events of the first UE group or the second UE group are detected, modify a handover triggering condition for a respective UE group; and

wherein said determining module is configured to determine whether there is any UE misidentified in the first or second UE group by:

in response that, after a predetermined number of said modifying or after a predetermined period of time of said modifying, the handover triggering condition for the first UE group or the second UE group fails to reach a steady state where the number of detected handover failure events in a respective UE group is below a predefined threshold, determining that a UE is misidentified in the respective UE group.

9. The base station of claim 8 , wherein said adjusting module is configured to adjust at least one of the criteria of identifying a UE as in the first UE group and the criteria of identifying a UE as in the second UE group by:

in response to determining that a UE is misidentified in the first UE group, upgrading the criteria of identifying a UE as in the first UE group and/or degrading the criteria of identifying a UE as in the second UE group; and

in response to determining that a UE is misidentified in the second UE group, degrading the criteria of identifying a UE as in the first UE group and/or upgrading the criteria of identifying a UE as in the second UE group.

10. The base station of claim 9 , wherein the criteria of identifying a UE as in the first UE group or the second UE group are based on Doppler Frequency-Offset Estimation, FOE, wherein a UE is identified as in the first UE group if a Doppler-FOE related parameter of the UE is higher than a third threshold, and a UE is identified as in the second UE group if the Doppler-FOE related parameter is lower than a fourth threshold; and

wherein said adjusting module is configured to degrade the criteria of identifying a UE as in the first UE group by decreasing the third threshold, to upgrade the criteria of identifying a UE as in the second UE group by decreasing the fourth threshold, to upgrade the criteria of identifying a UE as in the first UE group by increasing the third threshold, and to degrade the criteria of identifying a UE as in the second UE group by increasing the fourth threshold.

11. The base station of claim 7 , wherein said determining module is configured to determine whether there is any UE misidentified in the first or second UE group by:

in response that a predefined number of too-early handover events of the first UE group are detected where a difference of signal quality between a target cell and a source cell associated with a respective too-early handover event is larger than a first threshold, determining that a UE is misidentified in the first UE group; or

in response that a predefined number of too-late handover events of the second UE group are detected where a difference of signal quality between a target cell and a source cell associated with a respective too-late handover event is smaller than a second threshold, determining that a UE is misidentified in the second UE group.

12. The base station of claim 7 , wherein said determining module is configured to determine whether there is any UE misidentified in the first or second UE group by:

in response that a predefined number of too-early handover events are detected, determining that a UE is misidentified in the first UE group; or

in response that a predefined number of too-late handover events are detected, determining that a UE is misidentified in the second UE group.

13. A base station, BS, of a cellular radio system adapted for optimizing criteria of identifying a user equipment, UE, as in a first UE group or a second UE group, wherein a speed of any UE in the first UE group is higher than a speed of any UE in the second UE group, the base station comprising:

a processor; and a memory, said memory containing instructions executable by said processor, whereby said base station is operative to:

detect one or more handover failure events of at least one of the first UE group and the second UE group;

determine whether there is any UE misidentified in the first or second UE group based on the one or more handover failure events; and

in response to determining that there is a UE misidentified in the first or second UE group, adjust at least one of the criteria of identifying a UE as in the first UE group and the criteria of identifying a UE as in the second UE group.

14. The base station of claim 13 , wherein the base station is further operative to:

in response that a predefined number of too-early or too-late handover events of the first UE group or the second UE group are detected, modify a handover triggering condition for a respective UE group; and

wherein the base station is further operative to determine whether there is any UE misidentified in the first or second UE group by:

in response that, after a predetermined number of said modifying or after a predetermined period of time of said modifying, the handover triggering condition for the first UE group or the second UE group fails to reach a steady state where the number of detected handover failure events in a respective UE group is below a predefined threshold, determining that a UE is misidentified in the respective UE group.

15. The base station of claim 14 , wherein said base station is further operative to adjust at least one of the criteria of identifying a UE as in the first UE group and the criteria of identifying a UE as in the second UE group by:

in response to determining that a UE is misidentified in the first UE group, upgrading the criteria of identifying a UE as in the first UE group and/or degrading the criteria of identifying a UE as in the second UE group; and

in response to determining that a UE is misidentified in the second UE group, degrading the criteria of identifying a UE as in the first UE group and/or upgrading the criteria of identifying a UE as in the second UE group.

16. The base station of claim 15 , wherein the criteria of identifying a UE as in the first UE group or the second UE group are based on Doppler Frequency-Offset Estimation, FOE, wherein a UE is identified as in the first UE group if a Doppler-FOE related parameter of the UE is higher than a third threshold, and a UE is identified as in the second UE group if the Doppler-FOE related parameter is lower than a fourth threshold; and

wherein said base station is further configured to degrade the criteria of identifying a UE as in the first UE group by decreasing the third threshold, to upgrade the criteria of identifying a UE as in the second UE group by decreasing the fourth threshold, to upgrade the criteria of identifying a UE as in the first UE group by increasing the third threshold, and to degrade the criteria of identifying a UE as in the second UE group by increasing the fourth threshold.

17. The base station of claim 13 , wherein said base station is further operative to determine whether there is any UE misidentified in the first or second UE group by:

in response that a predefined number of too-early handover events of the first UE group are detected where a difference of signal quality between a target cell and a source cell associated with a respective too-early handover event is larger than a first threshold, determining that a UE is misidentified in the first UE group; or

in response that a predefined number of too-late handover events of the second UE group are detected where a difference of signal quality between a target cell and a source cell associated with a respective too-late handover event is smaller than a second threshold, determining that a UE is misidentified in the second UE group.

18. The base station of claim 13 , wherein said base station is further operative to determine whether there is any UE misidentified in the first or second UE group by:

in response that a predefined number of too-early handover events are detected, determining that a UE is misidentified in the first UE group; or

in response that a predefined number of too-late handover events are detected, determining that a UE is misidentified in the second UE group.

19. A base station, BS, of a cellular radio system adapted for optimizing criteria of identifying a user equipment, UE, as in a first UE group or a second UE group, wherein a speed of any UE in the first UE group is higher than a speed of any UE in the second UE group, the base station comprising:

processing means adapted to:

detect one or more handover failure events of at least one of the first UE group and the second UE group;

determine whether there is any UE misidentified in the first or second UE group based on the one or more handover failure events; and

in response to determining that there is a UE misidentified in the first or second UE group, adjust at least one of the criteria of identifying a UE as in the first UE group and the criteria of identifying a UE as in the second UE group.