A base station transmits on a first control channel first scheduling information for a control message. First radio resources of the first control channel start from the first symbol of each subframe in a plurality of subframes. The base station transmits the control message configuring second radio resources of a second control channel. The second radio resources comprise resource blocks in a subset of subframes in the plurality of subframes. The control message indicates the subset of subframes and a starting symbol of the second control channel. The base station transmits second scheduling information on the second control channel.