Cell activation and deactivation in a wireless network

1. A method comprising:

based on receiving, by a wireless device, a medium access control (MAC) control element (CE) indicating activation of a cell:

activating the cell; and

starting a first timer;

based on receiving downlink control information (DCI) indicating monitoring of a downlink control channel:

starting a second timer; and

monitoring the downlink control channel; and

based on one or more of the first timer expiring or receiving a second MAC CE indicating deactivation of the cell:

stopping the second timer; and

stopping the monitoring of the downlink control channel.

2. The method of claim 1 , further comprising restarting, based on receiving second DCI, the second timer.

3. The method of claim 1 , wherein the cell comprises a secondary cell.

4. The method of claim 1 , wherein the DCI is addressed to a temporary identifier associated with the wireless device.

5. The method of claim 4 , wherein the temporary identifier is a cell radio network temporary identifier (CRNTI).

6. The method of claim 1 , wherein the first timer comprises a deactivation timer for the cell.

7. The method of claim 1 , further comprising receiving configuration parameters comprising:

a first value for the first timer; and

a second value for the second timer.

8. A wireless device comprising:

one or more processors; and

memory storing instructions that, when executed by the one or more processors, cause the wireless device to:

based on receiving a medium access control (MAC) control element (CE) indicating activation of a cell:

activate the cell; and

start a first timer;

based on receiving downlink control information (DCI) indicating monitoring of a downlink control channel:

start a second timer; and

monitor the downlink control channel; and

based on one or more of the first timer expiring or receiving a second MAC CE indicating deactivation of the cell:

stop the second timer; and

stop monitoring of the downlink control channel.

9. The wireless device of claim 8 , wherein the instructions, when executed by the one or more processors, further cause the wireless device to restart, based on receiving second DCI, the second timer.

10. The wireless device of claim 8 , wherein the cell comprises a secondary cell.

11. The wireless device of claim 8 , wherein the DCI is addressed to a temporary identifier associated with the wireless device.

12. The wireless device of claim 11 , wherein the temporary identifier is a cell radio network temporary identifier (CRNTI).

13. The wireless device of claim 8 , wherein the first timer comprises a deactivation timer for the cell.

14. The wireless device of claim 8 , wherein the instructions, when executed by the one or more processors, further cause the wireless device to receive configuration parameters comprising:

a first value for the first timer; and

a second value for the second timer.

15. A non-transitory computer-readable medium comprising instructions that, when executed, cause a wireless device to:

based on receiving a medium access control (MAC) control element (CE) indicating activation of a cell:

activate the cell; and

start a first timer;

based on receiving downlink control information (DCI) indicating monitoring of a downlink control channel:

start a second timer; and

monitor the downlink control channel; and

based on one or more of the first timer expiring or receiving a second MAC CE indicating deactivation of the cell:

stop the second timer; and

stop monitoring of the downlink control channel.

16. The non-transitory computer-readable medium of claim 15 , wherein the instructions, when executed, further cause the wireless device to restart, based on receipt of second DCI, the second timer.

17. The non-transitory computer-readable medium of claim 15 , wherein the cell comprises a secondary cell.

18. The non-transitory computer-readable medium of claim 15 , wherein the DCI is addressed to a temporary identifier associated with the wireless device.

19. The non-transitory computer-readable medium of claim 18 , wherein the temporary identifier is a cell radio network temporary identifier (CRNTI).

20. The non-transitory computer-readable medium of claim 15 , wherein the first timer comprises a deactivation timer for the cell.

21. The non-transitory computer-readable medium of claim 15 , wherein the instructions, when executed, further cause the wireless device to receive configuration parameters comprising:

a first value for the first timer; and

a second value for the second timer.

22. A system comprising:

a base station configured to transmit a medium access control (MAC) control element (CE) indicating activation of a cell; and

a wireless device configured to:

based on receiving the MAC CE:

activate the cell; and

start a first timer;

based on receiving downlink control information (DCI) indicating monitoring of a downlink control channel:

start a second timer; and

monitor the downlink control channel; and

based on one or more of the first timer expiring or receiving a second MAC CE indicating deactivation of the cell:

stop the second timer; and

stop monitoring of the downlink control channel.

23. The system of claim 22 , wherein the wireless device is further configured to restart, based on receipt of a second DCI, the second timer.

24. The system of claim 22 , wherein the cell comprises a secondary cell.

25. The system of claim 22 , wherein the DCI is addressed to a temporary identifier associated with the wireless device.

26. The system of claim 25 , wherein the temporary identifier is a cell radio network temporary identifier (CRNTI).

27. The system of claim 22 , wherein the first timer comprises a deactivation timer for the cell.

28. The system of claim 22 , wherein:

the base station is further configured to transmit configuration parameters comprising:

a first value for the first timer; and

a second value for the second timer; and

the wireless device is further configured to receive the configuration parameters.