A radio base station allocates, when performing a real-time Internet-protocol data communication, up-link radio resources, based on basic information of transmission data, so that the transmission data is transmitted in synchronization with a codec cycle of a mobile communication terminal in a concentrated manner, and notifies a result of allocating the up-link radio resources to the mobile communication terminal as an up-transmission schedule. A mobile communication terminal controls transmission of a radio frame based on the up-transmission schedule.