A method and a radio base station for interleaving control channel data to be transmitted in a telecommunications system are described. The method comprises grouping the control channel elements CCE1-CCEn into a first order of control channel symbol groups, adding symbol groups comprising dummy values or zeros to the first order of control channel symbol groups based on a number of available symbol group positions for the shared control channel, interleaving the first order of the control channel symbol groups resulting in an a second order, and mapping the second order of control channel symbol groups to the available control channel transmission resources.