HANDOVER SOURCE RADIO BASE STATION, HANDOVER DESTINATION RADIO BASE STATION, RADIO COMMUNICATION SYSTEM AND RADIO COMMUNICATION METHOD

摘要

A radio base station determines, on the basis of a message when a call is originated from a user device, whether or not a VoLTE call originated from the user device is an emergency call. The radio base station is provided with a handover request transmission unit for transmitting a handover request to another radio base station, and the handover request transmission unit includes information indicating that the call is the emergency call in the handover request if it is determined that the call is the emergency call when transmitting the handover request before a voice default bearer for the emergency call is established after a voice default bearer for a general call has been established.