Method and system for processing measurement task in carrier aggregation system

1. A method for processing a measurement task in a carrier aggregation system, comprising:

deleting, by a network element, a measurement task related to a Secondary Cell (Scell) in a deleted source Scell,

when the measurement object configured by the source base station for an UE contains the carrier frequency of a new Primary Cell (Pcell) and the measurement object related to the measurement task is the frequency on which there is a target Pcell, modifying a corresponding measurement object to a measurement object of the frequency on which there is a new Pcell; and if the measurement object related to the measurement task is the frequency on which there is the source Pcell, modifying the measurement object to a measurement object of the frequency on which there is the new Pcell; otherwise, deleting the measurement task corresponding to the frequency on which there is the source Pcell; wherein the source Pcell and the target Pcell are on different frequencies.

2. The method according to claim 1 , wherein the network element comprises at least one of a User Equipment (UE) and a base station.

3. The method according to claim 1 , wherein an operation of deleting the source Scell is performed during a process of reassignment/handover/reconstruction.

4. The method according to claim 1 , further comprising:

if the source Scell is reassigned to another frequency on which there is a measurement object, modifying the measurement object corresponding to the measurement task related to the source Scell to a measurement object of the reassigned frequency, instead of deleting the measurement task related to the source Scell;

otherwise, deleting the measurement task related to the source Scell.

5. The method according to claim 1 , wherein the source Scell is deleted in the cases that there is no new Scell on the same frequency as a frequency on which there is the deleted source Scell after configuration, or there is no carrier identity corresponding to the source Scell.

6. The method according to claim 5 , further comprising:

when the measurement object configured by the source base station for an UE contains the carrier frequency of a new Primary Cell (Pcell) and the measurement object related to the measurement task is the frequency on which there is a target Pcell, modifying a corresponding measurement object to a measurement object of the frequency on which there is a new Pcell; and if the measurement object related to the measurement task is the frequency on which there is the source Pcell, modifying the measurement object to a measurement object of the frequency on which there is the new Pcell; otherwise, deleting the measurement task corresponding to the frequency on which there is the source Pcell; wherein the source Pcell and the target Pcell are on different frequencies.

7. The method according to claim 6 , further comprising:

carrying out no processing on the measurement tasks of the Pcell and the Scell when the source Pcell becomes an Scell and the source Scell becomes a Pcell.

8. The method according to claim 1 , wherein the source Scell is reassigned to another frequency on which there is a measurement object by changing the frequency of the source Scell with a carrier identity of the source Scell unchanged.

9. The method according to claim 1 , further comprising:

carrying out no processing on the measurement tasks of the Pcell and the Scell when the source Pcell becomes an Scell and the source Scell becomes a Pcell.

10. A system for processing a measurement task in a carrier aggregation system, comprising:

a deletion unit configured to delete all measurement tasks related to a source Secondary Cell (Scell),

or delete a measurement task related to an Scell in a deleted source Scell,

wherein the system further comprises:

a reassignment unit, configured to reassign the source Scell to another frequency on which there is a measurement object; accordingly, the deletion unit does not delete the measurement task related to the reassigned source Scell; and

a modification unit, configured to modify the measurement object corresponding to the measurement task related to the source Scell to the measurement object of the reassigned frequency;

wherein the modification unit is further configured to: modify, when the measurement object configured to the source base station for an UE contains a carrier frequency of a new Primary Cell (Pcell) and the measurement object related to the measurement task is a frequency on which there is a target Pcell, a corresponding measurement object to a measurement object of the frequency on which there is a new Pcell; and modify the measurement object to the measurement object related to the measurement task is the carrier frequency on which there is a source Pcell; otherwise, delete the measurement talk corresponding to the frequency on which there is the source Pcell; wherein the source Pcell and the target Pcell are on different frequencies;

each of the deletion unit, the reassignment unit, and the modification unit comprising a computer processor and respective memory, the respective memory storing computer-readable instructions which when executed by the computer processor implement the functions of the said units.

11. The system according to claim 10 , wherein a process in which the source Scell is deleted comprises that:

there is not a new Scell on the same frequency as a frequency on which there is the deleted source Scell after the configuration; or

there is not a carrier identity corresponding to a source secondary serving cell Scell.

12. The system according to claim 10 , wherein the source Scell is reassigned to the another frequency on which there is a measurement object by changing the frequency of the source Scell with the carrier identity of the source Scell unchanged.