Enhanced secondary cell activation command

1. A method comprising:

receiving, by a wireless device, a secondary cell activation command:

comprising a first bit, that is associated with a first secondary cell, and a second bit that is associated with a second secondary cell; and

indicating activation of the first secondary cell and activation of the second secondary cell;

wherein:

the secondary cell activation command indicates activation of a first reference signal for the activation of the first secondary cell; and

the secondary cell activation command indicates activation of no reference signal for the activation of the second secondary cell; and

activating the first secondary cell and the second secondary cell based on the secondary cell activation command.

2. The method of claim 1 , wherein the secondary cell activation command is a medium access control (MAC) control element (CE).

3. The method of claim 2 , wherein the MAC CE is associated with a first logical channel identifier indicating that the MAC CE is for secondary cell activation.

4. The method of claim 1 , further comprising receiving a reference signal configuration associated with an identifier, wherein the secondary cell activation command comprises a field with a value indicating the identifier.

5. The method of claim 4 , wherein the secondary cell activation command indicates activation of the first reference signal based on the value of the field.

6. The method of claim 4 , further comprising receiving the first reference signal, wherein:

the reference signal configuration indicates radio resources; and

the receiving the first reference signal is based on the radio resources.

7. The method of claim 1 , further comprising measuring the first reference signal in response to receiving the secondary cell activation command.

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:

receive a secondary cell activation command:

comprising a first bit, that is associated with a first secondary cell, and a second bit that is associated with a second secondary cell; and

indicating activation of the first secondary cell and activation of the second secondary cell;

wherein:

the secondary cell activation command indicates activation of a first reference signal for the activation of the first secondary cell; and

the secondary cell activation command indicates activation of no reference signal for the activation of the second secondary cell; and

activate the first secondary cell and the second secondary cell based on the secondary cell activation command.

9. The wireless device of claim 8 , wherein the secondary cell activation command is a medium access control (MAC) control element (CE).

10. The wireless device of claim 9 , wherein the MAC CE is associated with a first logical channel identifier indicating that the MAC CE is for secondary cell activation.

11. The wireless device of claim 8 , wherein the instructions, when executed by the one or more processors, further cause the wireless device to receive a reference signal configuration associated with an identifier, wherein the secondary cell activation command comprises a field with a value indicating the identifier.

12. The wireless device of claim 11 , wherein the secondary cell activation command indicates activation of the first reference signal based on the value of the field.

13. The wireless device of claim 11 , wherein the instructions, when executed by the one or more processors, further cause the wireless device to receive the first reference signal, wherein:

the reference signal configuration indicates radio resources; and

receiving the first reference signal is based on the radio resources.

14. The wireless device of claim 8 , wherein the instructions, when executed by the one or more processors, further cause the wireless device to measure the first reference signal in response to receiving the secondary cell activation command.

15. A system comprising:

a base station; and

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: receive, from the base station, a secondary cell activation command: comprising a first bit, that is associated with a first secondary cell, and a second bit that is associated with a second secondary cell; and indicating activation of the first secondary cell and activation of the second secondary cell; wherein: the secondary cell activation command indicates activation of a first reference signal for the activation of the first secondary cell; and the secondary cell activation command indicates activation of no reference signal for the activation of the second secondary cell; and activate the first secondary cell and the second secondary cell based on the secondary cell activation command.

16. The system of claim 15 , wherein the secondary cell activation command is a medium access control (MAC) control element (CE).

17. The system of claim 16 , wherein the MAC CE is associated with a first logical channel identifier indicating that the MAC CE is for secondary cell activation.

18. The system of claim 15 , wherein the instructions, when executed by the one or more processors, further cause the wireless device to receive a reference signal configuration associated with an identifier, wherein the secondary cell activation command comprises a field with a value indicating the identifier.

19. The system of claim 18 , wherein the secondary cell activation command indicates activation of the first reference signal based on the value of the field.

20. The system of claim 18 , wherein the instructions, when executed by the one or more processors, further cause the wireless device to receive the first reference signal, wherein:

the reference signal configuration indicates radio resources; and

receiving the first reference signal is based on the radio resources.