In one aspect, a wireless device receives a first data transmission from a base station in a first subframe interval and transmits HARQ feedback and/or CSI to the base station in a subsequent subframe interval, within a duration that is less than a maximum transmission duration that is possible within the subsequent subframe interval. In another aspect, a base station transmits a first data transmission to a wireless device in a first subframe interval and receives HARQ feedback and/or CSI from the wireless device in a subsequent subframe interval, within a duration that is less than a maximum transmission duration that is possible within the subsequent subframe interval.