A wireless device receives, from a first base station, configuration parameters indicating: a cell radio identifier of the wireless device; and random access preambles of a cell of a second base station. One or more random access preambles of the random access preambles using transmit beams is transmitted to the second base station via the cell. At least one random access response identified by the cell radio identifier of the wireless device is received. The at least one random access response comprises a first preamble identifier corresponding to a first random access preamble of the one or more random access preambles. The first random access preamble is transmitted by a first transmit beam of the transmit beams. Data using the first transmit beam is transmitted to the second base station.