Method of reference cell maintenance

1. A method of reference cell maintenance for a mobile device in a wireless communication system, the method comprising:

being configured a plurality of secondary cells, where one of the plurality of secondary cells is a reference cell for information reference for another secondary cell;

keeping the reference cell in activated when the reference cell is used by the another secondary cell for information reference, wherein keeping the reference cell in activated when the reference cell is used by the another secondary cell for information reference comprises:

starting or restarting a first deactivation timer for the reference cell when the reference cell is used by the another secondary cell for information reference and when a second deactivation timer for the another secondary cell is started or restarted, wherein the first or the second deactivation timer is used for providing a period of time for secondary cell activation, and wherein starting or restarting the second deactivation timer for the another secondary cell comprises:

receiving a physical downlink control channel (PDCCH) indicating an uplink grant or a downlink assignment for the another secondary cell; and

starting or restarting a prohibit timer for the reference cell when the first deactivation timer for the reference cell is started or restarted;

wherein starting or restarting the first deactivation timer for the reference cell when the reference cell is used by another secondary cell for information reference and the second deactivation timer for the another secondary cell is started or restarted comprises:

starting or restarting the first deactivation timer for the reference cell when the reference cell is used by another secondary cell for information reference, the second deactivation timer for the another secondary cell is started or restarted, and the prohibit timer expires.

2. The method of claim 1 , wherein keeping the reference cell in activated when the reference cell is used by another secondary cell for information reference comprises:

starting or restarting an extension timer for the reference cell when the reference cell is used by another secondary cell for information reference and a deactivation timer for the another secondary cell is started or restarted, wherein the deactivation timer used for providing a period of time for secondary cell activation, and the extension timer is a specific timer used for providing a period time for reference cell activation.

3. The method of claim 2 , wherein starting or restarting the extension timer for the reference cell when the reference cell is used by another secondary cell for information reference and the deactivation timer for the another secondary cell is started or restarted comprises:

starting or restarting the extension timer for the reference cell when the reference cell is used by another secondary cell for information reference, the deactivation timer for the another secondary cell is started or restarted and a time alignment timer (TAT) for the another secondary cell or for a time alignment (TA) group including the another secondary cell is running, wherein the TAT is used for indicating uplink transmission synchronization.

4. The method of claim 3 , further comprising:

starting or restarting a prohibit timer for the reference cell when the extension timer for the reference cell is started or restarted;

wherein starting or restarting the extension timer for the reference cell when the reference cell is used by another secondary cell for information reference, the deactivation timer for the another secondary cell is started or restarted, and the TAT is running comprises:

starting or restarting the extension timer for the reference cell when the reference cell is used by another secondary cell for information reference, the deactivation timer for the another secondary cell is started or restarted, the TAT is running, and the prohibit timer expires.

5. The method of claim 2 , further comprising:

starting or restarting a prohibit timer for the reference cell when the extension timer for the reference cell is started or restarted;

wherein starting or restarting the extension timer for the reference cell when the reference cell is used by another secondary cell for information reference and the deactivation timer for the another secondary cell is started or restarted comprises:

starting or restarting the extension timer for the reference cell when the reference cell is used by another secondary cell for information reference, the deactivation timer for the another secondary cell is started or restarted, and the prohibit timer expires.

6. The method of claim 1 , wherein keeping the reference cell in activated when the reference cell is used by another secondary cell for information reference comprises:

starting or restarting a deactivation timer for the reference cell when the reference cell is used by another secondary cell for information reference and an uplink grant is allocated for the another secondary cell, wherein the deactivation timer is used for providing a period of time for reference cell activation; or

starting or restarting an extension timer for the reference cell when the reference cell is used by another secondary cell for information reference and an uplink grant is allocated for the another secondary cell, wherein the extension timer is a specific timer used for providing a period time for reference cell activation.

7. The method of claim 6 , wherein starting or restarting the deactivation timer for the reference cell when the reference cell is used by another secondary cell for information reference and the uplink grant is allocated for the another secondary cell comprises:

starting or restarting the deactivation timer for the reference cell when the reference cell is used by another secondary cell for information reference, the uplink grant is allocated for the another secondary cell and a time alignment timer (TAT) for the another secondary cell or for a time alignment (TA) group including the another secondary cell is running, wherein the TAT is used for indicating uplink transmission synchronization; and

starting or restarting the extension timer for the reference cell when the reference cell is used by another secondary cell for information reference and an uplink grant is allocated for the another secondary cell comprises:

starting or restarting the extension timer for the reference cell when the reference cell is used by another secondary cell for information reference, an uplink grant is allocated for the another secondary cell, and the TAT is running.

8. The method of claim 7 , further comprising:

starting or restarting a prohibit timer for the reference cell when the extension timer for the reference cell is started or restarted;

wherein starting or restarting the deactivation timer for the reference cell when the reference cell is used by another secondary cell for information reference, the uplink grant is allocated for the another secondary cell, and the TAT is running comprises:

starting or restarting the deactivation timer for the reference cell when the reference cell is used by another secondary cell for information reference, the uplink grant is allocated for the another secondary cell, the TAT is running, and the prohibit timer expires; and

wherein starting or restarting the extension timer for the reference cell when the reference cell is used by another secondary cell for information reference, the uplink grant is allocated for the another secondary cell, and the TAT is running comprises:

starting or restarting the extension timer for the reference cell when the reference cell is used by another secondary cell for information reference, the uplink grant is allocated for the another secondary cell, the TAT is running, and the prohibit timer expires.

9. The method of claim 6 , further comprising:

starting or restarting a prohibit timer for the reference cell when the extension timer for the reference cell is started or restarted;

wherein starting or restarting the deactivation timer for the reference cell when the reference cell is used by another secondary cell for information reference and the uplink grant is allocated for the another secondary cell comprises:

starting or restarting a deactivation timer for the reference cell when the reference cell is used by another secondary cell for information reference, the uplink grant is allocated for the another secondary cell, and the prohibit timer expires; or

starting or restarting the extension timer for the reference cell when the reference cell is used by another secondary cell for information reference, the uplink grant is allocated for the another secondary cell, and the prohibit timer expires.

10. The method of claim 1 , wherein starting or restarting the first deactivation timer for the reference cell when the reference cell is used by another secondary cell for information reference and the second deactivation timer for the another secondary cell is started or restarted comprises:

starting or restarting the first deactivation timer for the reference cell when the reference cell is used by another secondary cell for information reference, the second deactivation timer for the another secondary cell is started or restarted, and a time alignment timer (TAT) for the another secondary cell or for a time alignment (TA) group including the another secondary cell is running, wherein the TAT is used for indicating uplink transmission synchronization.

11. The method of claim 10 , further comprising:

starting or restarting a prohibit timer for the reference cell when the first deactivation timer for the reference cell is started or restarted;

wherein starting or restarting the first deactivation timer for the reference cell when the reference cell is used by another secondary cell for information reference, the second deactivation timer for the another secondary cell is started or restarted, and the TAT is running comprises:

starting or restarting the first deactivation timer for the reference cell when the reference cell is used by another secondary cell for information reference, the second deactivation timer for the another secondary cell is started or restarted, the TAT is running, and the prohibit timer expires.

12. The method of claim 1 , wherein keeping the reference cell in activated when the reference cell is used by another secondary cell for information reference comprises:

using a deactivation timer for the reference cell with a long activation length compared to a normal activation length when the reference cell is used by another secondary cell for information reference and the another secondary cell is activated, wherein the deactivation timer is used for providing a period of time for secondary cell activation.

13. The method of claim 12 , wherein configuring the deactivation timer for the reference cell with a long activation length compared to a normal activation length when the reference cell is used by another secondary cell for information reference comprises:

using the deactivation timer for the reference cell with a long activation length compared to a normal activation length when the reference cell is used by another secondary cell for information reference, the another secondary cell is activated, and a time alignment timer (TAT) for the another secondary cell or for a time alignment (TA) group including the another secondary cell is running, wherein the TAT is used for indicating uplink transmission synchronization.

14. The method of claim 1 , wherein keeping the reference cell in activated when the reference cell is used by the another secondary cell for information reference comprises:

suspending or stopping a deactivation timer for the reference cell when the reference cell is used by the another secondary cell for information reference, and the another secondary cell is activated, wherein the deactivation timer is for providing a period of time for reference cell activation.

15. The method of claim 14 , wherein suspending or stopping the deactivation timer for the reference cell when the reference cell is used by the another secondary cell for information reference, and the another secondary cell is activated comprise:

suspending or stopping the deactivation timer for the reference cell when the reference cell is used by the another secondary cell for information reference, the another secondary cell is activated, and a time alignment timer (TAT) for the another secondary or for a time alignment (TA) group including the another secondary cell is running, wherein the TAT is used for indicating uplink transmission synchronization.

16. The method of claim 1 , wherein the reference cell is a timing reference cell or a pathloss reference cell.