A wireless device transmits a first sounding reference signal (SRS) in a first cell overlapping in time with transmission of a packet in a second cell. The first cell and the second cell are different cells of the same cell group. The wireless device drops a second SRS in the first cell when the second SRS is configured for transmission in parallel with a preamble in a cell group comprising the first cell. The wireless device has sufficient power to transmit uplink signals.