Base station, user terminal, radio communication system, and communication control method

A user terminal that communicates with a primary cell and a secondary cell by radio, comprising:

• a receiver that receives a higher layer signaling;
• and
• a controller that sets:
• a first communication usage of a first radio communication resource, which is divided into periods of communication usage, to be used in the primary cell and
• a second communication usage, which is divided into periods of communication usage, of a second radio communication resource to be used in the secondary cell, based on the higher layer signaling,
• wherein, based on the higher layer signaling, the controller uses the first radio communication resource and the second communication resource as a radio communication resource including a period of communication usage of the respective periods of communication usage that is neither a period for transmission of a downlink signal nor a period for transmission of an uplink signal.