A method in a communication system, in which multiple transmitters transmit respective control messages to a receiver over a control channel, includes allocating respective resources of the control channel to the control messages so as to cause a respective likelihood of interference between a control message and at least one other control message to be inversely related to a respective impact of the interference between the control message and the at least one other control message on an overall performance measure defined for the communication system, by allocating a dedicated resource to a first control message for which the interference has a high impact on the overall performance measure, and allocating a shared resource to a second control message for which the interference has a low impact on the overall performance measure. The control messages are transmitted from the transmitters over the control channel using the allocated resources.