Control message(s) are transmitted to a wireless device. The control message(s) comprise configuration parameters of cells comprising secondary cells, and parameters for configuration of a random access channel of at least one secondary cell in the plurality of secondary cells. The cells are grouped into cell groups comprising a primary cell group and a secondary cell group. A control command is transmitted. The control command is configurable to cause transmission of a first random access preamble on any one of the secondary cell(s) in the secondary cell group, and unconfigurable to cause transmission of a second random access preamble on any secondary cell in the primary cell group.