A wireless device receives RRC message(s) configuring transmissions of sounding reference signals on a second carrier in a second carrier group. The wireless device receives a random access response comprising a long time alignment value and a preamble identifier. The wireless device transmits the sounding reference signals on the second carrier after adjusting uplink transmission timing of the second carrier group. The wireless device is configured to not transmit any of the sounding reference signals on the second carrier until the wireless device receives the random access response comprising the long time alignment value and an uplink grant.