DATA DISTRIBUTION METHOD AND SYSTEM FOR SWITCHING BASE STATION PERFORMING MULTICAST TRANSMISSION, DEPENDING ON RADIO TERMINAL

PROBLEM TO BE SOLVED: To provide a data distribution method and system for enabling a radio terminal to switch to a peripheral base station distributing large-volume band candidate data.SOLUTION: A distribution server distributes all of a plurality of band candidate data depending on each base station to the base station. Then, the plurality of base stations distribute any one of the band candidate data selected depending on a communication use band with a radio terminal to the radio terminal, and notify the distribution server of identifiers of the band candidate data. Then, the radio terminal transmits a base station ID of a base station with which the radio terminal is communicating currently and a base station ID of a peripheral base station with which the radio terminal can communicate, to the distribution server. Then, the distribution server transmits a base station ID of a base station which distributes band candidate data having the largest volume multicast data among the peripheral base stations, to the radio terminal. Then, the radio terminal switches from the base station with which the radio terminal is communicating currently to the base station based on the base station ID received from the distribution server.