A communication system that includes at least a terminal apparatus and a base station apparatus. The terminal apparatus communicates with a base station apparatus by carrier aggregation using a plurality of serving cells, wherein each serving cell of the plurality of serving cells has a different frequency. The terminal apparatus receives (from the base station apparatus) a measurement configuration which includes a reporting configuration, a measurement object to indicate a measurement frequency and a measurement identity which links the measurement object to the reporting configuration. The terminal apparatus, in a case that an entry condition of the event corresponding with an event identity of the reporting configuration is fulfilled, transmits (to the base station apparatus) a measurement report which includes measurement results of all of the serving cells.