A base station transmits first scheduling information on a first control channel for a first packet communicated with a first wireless device. First radio resources of the first control channel start from the first OFDM symbol of each subframe. The base station transmits a radio resource control (RRC) message causing configuration of second radio resources of a second control channel in a second wireless device. The second radio resources comprise resource blocks in a subset of subframes. The base station transmits second scheduling information on the second control channel for a second packet communicated with the second wireless device.