The present invention relates to methods and arrangements in a wireless communication system supporting carrier aggregation and comprising a radio base station configured to broadcast system information in at least two cells. The method for the user equipment comprises receiving configuration information for an aggregation of the at least two cells from the radio base station, identifying a first of the at least two cells based on a configuration rule stating that the first of the at least two cells has a status that is different from the status of the remaining cells, and reading the broadcasted system information only in the identified cell. The method may also comprise obeying one or more parameters obtained from the read system information.