A wireless device receives a radio resource control message comprising an aperiodic sounding reference signal (SRS) subframe parameter. A downlink control information is received. The downlink control information indicates uplink resources in a plurality of scheduled consecutive subframes for transmission of transport blocks by the wireless device and triggers an SRS transmission in a subframe of the plurality of scheduled consecutive subframes. The SRS is transmitted in the subframe. A position of the subframe in the plurality of scheduled consecutive subframes is determined based on the aperiodic SRS subframe parameter.