ACTIVATION DELAY FOR PUCCH SCELL BASED ON UL RESPONSE

摘要

This invention relates generally to primary and secondary cells for carrier aggregation and, provides a method, an apparatus, a communication system, a computer program and a computer readable medium storing a computer program related thereto. The method comprises sending from a base station an activation command to a user equipment for activating a secondary cell with a physical uplink control channel for use by the user equipment; sending after an activation delay a physical downlink control channel order message to the user equipment on a physical downlink control channel for the secondary cell; and receiving, responsive to the physical downlink control channel order message, a random access response from the user equipment on the physical uplink control channel for the secondary cell.