Carrier selection in a multi-carrier wireless network
A wireless device receives a downlink control information (DCI) on a primary cell. The DCI may comprise a field instructing a wireless device to activate a secondary cell. The wireless device activates the secondary cell in response to receiving the DCI.
1. A method comprising:
receiving, by a wireless device from a base station, one or more messages comprising configuration parameters of a cell, wherein the configuration parameters comprise:
a first value for a first timer; and
a second value for a second timer;
starting, based on the first value and a medium-access control (MAC) control element (CE), the first timer;
receiving, via a primary cell, downlink control information (DCI), wherein the DCI comprises a field indicating an activation for a secondary cell;
starting, based on the second value and the DCI, the second timer; and
activating, while the first timer and the second timer are both running, the secondary cell.
2. The method of claim 1 , further comprising restarting, based on receiving second DCI, the second timer.
3. The method of claim 1 , further comprising stopping the second timer based on one or more of:
the first timer expiring; or
receiving a second MAC CE, wherein the second MAC CE indicates a deactivation of the cell.
4. The method of claim 1 , further comprising:
monitoring, based on the receiving the DCI, a downlink control channel; and
stopping, based on the second timer expiring and while an activation status of the cell is maintained, the monitoring the downlink control channel.
5. The method of claim 4 , wherein the activation status of the cell is maintained by at least one of:
measuring one or more reference signals; or
monitoring a second downlink control channel for receiving the DCI.
6. The method of claim 5 , wherein one of the one or more reference signals is a channel state information reference signal.
7. The method of claim 1 , further comprising:
receiving the MAC CE; and
activating, based on the receiving the MAC CE, the cell.
8. A method comprising:
receiving, by a wireless device from a base station, one or more messages comprising configuration parameters of a cell, wherein the configuration parameters comprise:
a first value for a first timer; and
a second value for a second timer, wherein the second timer is for monitoring a downlink control channel;
receiving a medium-access control (MAC) control element (CE) indicating an activation of the cell;
based on the receiving the MAC CE:
activating the cell; and
starting the first timer;
receiving first downlink control information (DCI) indicating monitoring the downlink control channel;
based on the receiving the first DCI:
starting the second timer; and
monitoring the downlink control channel; and
receiving, while the first timer and the second timer are both running, second DCI comprising one or more of a downlink assignment or an uplink grant.
9. The method of claim 8 , further comprising restarting, based on the receiving the second DCI, the second timer.
10. The method of claim 8 , further comprising:
stopping the second timer; and
stopping the monitoring the downlink control channel;
wherein the stopping the second timer and the stopping the monitoring the downlink control channel are based on one or more of:
the first timer expiring; or
receiving a second MAC CE, wherein the second MAC CE indicates a deactivation of the cell.
11. The method of claim 8 , further comprising stopping, based on the second timer expiring and while an activation status of the cell is maintained, the monitoring the downlink control channel.
12. The method of claim 11 , wherein the activation status of the cell is maintained by at least one of:
measuring one or more reference signals; or
monitoring a second downlink control channel for receiving the first DCI.
13. The method of claim 12 , wherein one of the one or more reference signals is a channel state information reference signal.
14. The method of claim 8 , wherein the activating the cell comprises measuring one or more reference signals.
15. A method comprising:
transmitting, by a base station to a wireless device, one or more messages comprising configuration parameters of a cell, wherein the configuration parameters comprise:
a first value for a first timer; and
a second value for a second timer, wherein the second timer is for monitoring a downlink control channel;
transmitting a medium-access control (MAC) control element (CE) indicating an activation of the cell;
based on the transmitting the MAC CE:
activating the cell; and
starting the first timer;
transmitting first downlink control information (DCI) indicating monitoring the downlink control channel;
based on the transmitting the first DCI:
starting the second timer; and
monitoring the downlink control channel; and
transmitting, while the first timer and the second timer are both running, second DCI comprising one or more of a downlink assignment or an uplink grant.
16. The method of claim 15 , further comprising restarting, based on the transmitting the second DCI, the second timer.
17. The method of claim 15 , further comprising:
stopping the second timer; and
stopping the monitoring the downlink control channel;
wherein the stopping the second timer and the stopping the monitoring the downlink control channel are based on one or more of:
the first timer expiring; or
transmitting a second MAC CE, wherein the second MAC CE indicates a deactivation of the cell.
18. The method of claim 15 , further comprising stopping, based on the second timer expiring and while an activation status of the cell is maintained, the monitoring the downlink control channel.
19. The method of claim 18 , wherein the activation status of the cell is maintained by at least measuring one or more reference signals.
20. The method of claim 15 , wherein activating the cell comprises measuring one or more reference signals.