The invention relates to a user equipment for being scheduled with uplink radio resources. The user equipment receives from a radio base station a first-stage uplink resource scheduling message, indicating uplink radio resources usable by the UE to perform an uplink transmission via an unlicensed cell. The receiver further receives a second-stage uplink resource scheduling message, which is related to the first-stage uplink resource scheduling message. Upon reception of the second-stage uplink resource scheduling message, a processor of the UE determines that an uplink transmission is scheduled in case the first-stage uplink resource scheduling message is valid. The first-stage uplink resource scheduling message is determined valid based on a determination as to whether an uplink transmission has been triggered by another second-stage uplink resource scheduling message within a predetermined time period prior to reception of the second-stage uplink resource scheduling message. The UE then performs an uplink transmission.