A base station, a processor thereof, and a communication control method thereof receive a notification from a first user terminal before starting direct device to device (D2D) communication, the notification indicating a desire for performing D2D communication, receive a measurement report including results of measurement of a cell reference signal from the first user terminal, and based on the measurement report, determine to cause the first user terminal to perform D2D communication, perform a process for starting the D2D communication between the first and second user terminals, receive a first data amount notification indicating an amount of first data to be transmitted from the first user terminal to the second user terminal, and based on the first data amount notification, allocate first radio resources to the first user terminal, where the allocated first radio resources are used by the first user terminal to transmit the first data.