A method is disclosed for operating a communication device that is configured with a plurality of cells to provide carrier aggregation for communication with a wireless communication network. The method includes receiving an instruction to activate a cell of the plurality of cells that are configured for the communication device, and starting a discontinuous reception (DRX) inactivity timer associated with the cell of the plurality of cells responsive to receiving the instruction to active the cell of the plurality of cells. Corresponding communication devices are disclosed. Also, related radio access network nodes and methods are disclosed.