A wireless device may receive, during a transmission time interval (TTI), a media-access-control control element (MAC CE) comprising at least one parameter indicating, to the wireless device, to activate at least one licensed cell and at least one unlicensed cell. The wireless device may perform channel monitoring on the at least one unlicensed cell before a first maximum duration after the TTI. The wireless device may perform channel monitoring on the at least one licensed cell after initiating the channel monitoring on the unlicensed cell and before a second maximum duration after the TTI. The first maximum duration and the second maximum duration may be different.