Activation and deactivation of bandwidth part
A wireless device receives from a base station, message(s) comprising configuration parameters of a cell. The configuration parameters may comprise BWP parameters of a first BWP and a second BWP, and a timer value associated with a BWP inactivity timer. A first DCI may be received at a first slot. The first DCI may indicate switching to the second BWP as an active BWP. In response to the first DCI, the first BWP may switch to the second BWP as the active BWP. In response to the first DCI, the BWP inactivity timer may be started at a second slot based on the timer value. The second slot may occur after the first slot by an amount of time determined based on a time offset value. A default BWP may be switched to in response to an expiry of the BWP inactivity timer.
1. A method comprising:
receiving, by a wireless device from a base station, one or more messages comprising configuration parameters of a cell, the configuration parameters comprising:
bandwidth part (BWP) parameters of a first BWP and a second BWP; and
a timer value associated with a BWP inactivity timer;
receiving, at a first slot, a first downlink control information indicating switching to the second BWP as an active BWP;
in response to the first downlink control information:
switching from the first BWP to the second BWP as the active BWP; and
starting, at a second slot after the switching from the first BWP to the second BWP as the active BWP, the BWP inactivity timer based on the timer value, wherein the second slot occurs after the first slot by an amount of time determined based on a time offset value, wherein the time offset value is based on a capability, of the wireless device, for bandwidth part switching; and
switching to a default BWP in response to an expiry of the BWP inactivity timer.
2. The method of claim 1 , wherein the time offset value is indicated in the configuration parameters.
3. The method of claim 1 , wherein the time offset value is a fixed value.
4. The method of claim 1 , wherein the cell is a primary cell of a plurality of cells.
5. The method of claim 1 , wherein the cell is a secondary cell of a plurality of cells.
6. The method of claim 1 , wherein the BWP parameters of the first BWP or the second BWP indicate at least one of:
a frequency location;
a bandwidth;
a value of subcarrier spacing;
a cyclic prefix; or
one or more reference signal resource configurations.
7. The method of claim 1 , further comprising activating the first BWP in response to receiving a second downlink control information indicating a downlink assignment or an uplink grant.
8. The method of claim 7 , further comprising starting the BWP inactivity timer in response to the second downlink control information.
9. The method of claim 1 , further comprising activating the first BWP in response to receiving a command indicating an activation of the cell.
10. The method of claim 9 , wherein the command is one of:
a medium access control control element; and
a second downlink control information.
11. The method of claim 9 , further comprising starting the BWP inactivity timer based on the timer value in response to the command.
12. The method of claim 9 , wherein activating the first BWP comprises monitoring a downlink control channel on the first BWP.
13. The method of claim 1 , wherein switching from the first BWP to the second BWP as the active BWP comprises at least one of:
stopping monitoring a first downlink control channel on the first BWP; or
monitoring a second downlink control channel on the second BWP.
14. The method of claim 1 , further comprising:
receiving at a third slot, a second downlink control information indicating switching to a default BWP as the active BWP; and
in response to the second downlink control information:
switching the active BWP to the default BWP; and
stopping the BWP inactivity timer.
15. The method of claim 14 , wherein the default BWP is different from the second BWP.
16. The method of claim 14 , wherein the switching the active BWP to the default BWP comprises monitoring a downlink control channel on the default BWP.
17. The method of claim 14 , wherein the stopping the BWP inactivity timer comprises stopping the BWP inactivity timer at the third slot.
18. The method of claim 1 , wherein a first bandwidth of the first BWP is less than a second bandwidth of the cell.
19. The method of claim 1 , further comprising stopping the BWP inactivity timer in response to receiving a command indicating a deactivation of the cell.