User apparatus, and uplink transmission switching method

Abstract

A user apparatus which performs communications with one or more base stations in a communication system which supports carrier aggregation is provided. The user apparatus includes a control unit configured to select a specific cell or a specific cell group as a reference of an uplink transmission carrier switching timing, from a plurality of cells or a plurality of cell groups with which the carrier aggregation is configured; and a transmission unit configured to perform switching from uplink transmission using a first cell carrier to uplink transmission using a second cell carrier based on a transient period timing in the selected specific cell or specific cell group.

Dependencies are inferred from the claim text.