Radio communication system, radio base station apparatus, terminal apparatus, and radio resource allocation method

A radio communication system comprising:

• a first and second radio base station apparatuses;
• and
• a first to third terminal apparatuses, wherein
• the first radio base station apparatus includes:
• a radio resource control unit configured to allocate to the first terminal apparatus a second radio resource, in contrast to a first radio resource allocated when the first terminal apparatus performs first radio communication via the first radio base station apparatus, when the first terminal apparatus performs second radio communication with the second terminal apparatus not via the first radio base station apparatus, and
• a first transmission unit configured to transmit allocation information of the second radio resource to the first terminal apparatus,
• the first terminal apparatus includes a reception unit configured to receive the allocation information from the first radio base station apparatus, and
• the second radio resource is same as or partially overlapped with a third radio resource allocated, by the second radio base station apparatus, when the third terminal apparatus performs the second radio communication.