A wireless device receives one or more messages comprising configuration parameters of a licensed assisted access (LAA) cell. The wireless device receives a downlink control information (DCI) for the LAA cell. The DCI may comprise a first field and a second field. The first field indicates uplink resources for an uplink subframe of the LAA cell. The second field indicates a first starting position in a plurality of starting positions in the uplink subframe. The first starting position in the uplink subframe is determined, at least, based on a sum of twenty-five micro-seconds plus a timing advance value. The wireless device constructs one or more transport blocks employing the DCI. The wireless device transmits the one or more transport blocks in the uplink resources starting from the first starting position of the uplink subframe.