Transitioning cell to dormant state

1. A method comprising:

transmitting, by a base station, a first downlink control information (DCI) to a wireless device to indicate the wireless device to activate a power saving (PS) mode; wherein the wireless device skips monitoring physical downlink control channel (PDCCH) in a discontinuous reception (DRX) active time of a DRX cycle in the PS mode;

transmitting, by the base station, a second DCI comprising:

a bandwidth part indicator field; and

a frequency domain resource assignment field;

transitioning a secondary cell to a dormant state, by the base station, based on the frequency domain resource assignment field being set to a predefined value; and

transmitting, by the base station, a third DCI to the wireless device to indicate the wireless device to deactivate the PS mode, wherein the first DCI and third DCI have a same DCI format.

2. The method of claim 1 , further comprising receiving, by the base station from a wireless device, information indicating whether a power saving mode is triggered; in response to receiving the information, the base station allocates to the wireless device a first RNTI dedicated for the PS mode.

3. The method of claim 1 , wherein the predefined value comprises:

a bit string of zeros; or

a bit string of ones.

4. The method of claim 1 , wherein the bandwidth part indicator field indicates an active bandwidth part for a serving cell.

5. The method of claim 1 , further comprising:

receiving, from a wireless device, one or more assistance parameters of the wireless device indicating whether the wireless device supports a dormancy state transition; and

transmitting, by the base station to the wireless device, configuration parameters of the dormant state for the secondary cell based on the one or more assistance parameters.

6. The method of claim 1 , wherein based on the secondary cell being in the dormant state, the base station stops transmitting via a downlink control channel on the secondary cell.

7. The method of claim 1 , wherein based on the secondary cell being in the dormant state, the base station stops transmitting downlink packets via the secondary cell.

8. The method of claim 1 , wherein based on the secondary cell being in the dormant state, the base station stops receiving uplink signals via the secondary cell.

9. The method of claim 1 , wherein the downlink control information comprises a plurality of dormancy indications, each of the plurality of dormancy indications corresponding to one or more cells of a plurality of cells.

10. The method of claim 1 , wherein the downlink control information comprises a modulation and coding scheme field, a new data indicator field, and/or a redundancy version field.

11. A base station comprising one or more processors and memory storing instructions that, when executed by the one or more processors, cause the base station to:

transmit a first downlink control information (DCI) to a wireless device to indicate the wireless device to activate a power saving (PS) mode; wherein the wireless device skips monitoring physical downlink control channel (PDCCH) in a discontinuous reception (DRX) active time of a DRX cycle in the PS mode;

transmit a second DCI comprising:

a bandwidth part indicator field; and

a frequency domain resource assignment field;

transition a secondary cell to a dormant state based on the frequency domain resource assignment field being set to a predefined value; and

transmit a third DCI to the wireless device to indicate the wireless device to deactivate the PS mode, wherein the first DCI and third DCI have a same DCI format.

12. The method of claim 1 , further comprising receiving, from a wireless device, information indicating whether a power saving mode is triggered; in response to receiving the information, the base station allocates to the wireless device a first RNTI dedicated for the PS mode.

13. The method of claim 1 , wherein the predefined value comprises:

a bit string of zeros; or

a bit string of ones.

14. The method of claim 1 , wherein the bandwidth part indicator field indicates an active bandwidth part for a serving cell.

15. The method of claim 1 , wherein the instructions cause the base station to:

receive, from a wireless device, one or more assistance parameters of the wireless device indicating whether the wireless device supports a dormancy state transition; and

transmit, to the wireless device, configuration parameters of the dormant state for the secondary cell based on the one or more assistance parameters.

16. The method of claim 1 , wherein the instructions cause the base station to stop transmitting via a downlink control channel on the secondary cell based on the secondary cell being in the dormant state.

17. The method of claim 1 , wherein the instructions cause the base station to stop transmitting downlink packets via the secondary cell based on the secondary cell being in the dormant state.

18. The method of claim 1 , wherein the instructions cause the base station to stop receiving uplink signals via the secondary cell based on the secondary cell being in the dormant state.

19. The method of claim 1 , wherein the downlink control information comprises a plurality of dormancy indications, each of the plurality of dormancy indications corresponding to one or more cells of a plurality of cells.

20. A system comprising:

a base station comprising one or more processors and memory storing instructions that, when executed by the one or more processors, cause the base station to:

transmit a first downlink control information (DCI) to a wireless device to indicate the wireless device to activate a power saving (PS) mode; wherein the wireless device skips monitoring physical downlink control channel (PDCCH) in a discontinuous reception (DRX) active time of a DRX cycle in the PS mode;

transmit a second DCI comprising:

a bandwidth part indicator field; and

a frequency domain resource assignment field;

transition a secondary cell to a dormant state based on the frequency domain resource assignment field being set to a predefined value; and

transmit a third DCI to the wireless device to indicate the wireless device to deactivate the PS mode, wherein the first DCI and third DCI have a same DCI format; 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 the first DCI and activate the PS mode; wherein the wireless device skips monitoring physical downlink control channel (PDCCH) in a discontinuous reception (DRX) active time of a DRX cycle in the PS mode;

receive the second DCI comprising:

the bandwidth part indicator field; and

the frequency domain resource assignment field;

transition the second cell to the dormant state based on the frequency domain resource assignment field being set to the predefined value; and

receive third DCI to the wireless device and deactivate the PS mode.