Multicast service providing system, multicast service providing method, information distributor, radio terminal, and radio base station

An information distributing apparatus which performs multicast information distribution service via a radio section to a radio terminal present within a service area, comprising:

• service continuation management means managing as to whether or not service continuation request has been made by the radio terminal for the multicast information distribution service,
• information managed by said service continuation management means indicating as to whether or not continuation request for the multicast information distribution service being transmitted to the radio terminal.

A radio terminal which receives multicast information distribution service from an information distributing apparatus via a radio section, comprising:

• service continuation request means transmitting a service continuation request signal for requesting provision of the multicast information distribution service, to the information distributing apparatus;
• and
• continuation request control means controlling said service continuation request means so as to cause it to transmit the service continuation request signal to the information distributing apparatus when information indicating whether or not service continuation request has been made by the radio terminal for the multicast information distribution service, transmitted by the information distributing apparatus which manages as to whether or not the service continuation request has been made by the radio terminal for the multicast information distribution service, indicates a state that the request has not been made.

A multicast service providing method by which multicast information distribution service is performed by an information distributing apparatus via a radio section on radio terminals present in a service area thereof:

• wherein:
• the information distributing apparatus informs all the radio terminals present in the service area of information for identifying multicast information on distribution and radio channels including at least one frequency number used for the distribution of the multicast information by using a single message sent on a predetermined radio channel, and
• the respective radio terminals within the service area receive the multicast information distribution service from the information distributing apparatus via the thus- informed radio channels.

A multicast service providing system in which multicast information distribution service is made by an information distributing apparatus to radio terminals present within a service area via a radio section, wherein:

• the information distributing apparatus has information control means informing, by using a single message sent on a predetermined radio channel, all the radio terminals present within the service area, of information for identifying multicast information on distribution service and radio channels including at least one frequency number used for distributing the multicast information;
• and
• each radio terminal present within the service area receives the multicast information distribution service from the information distributing apparatus by using the radio channels thus informed of.

An information distributing apparatus performing multicast information distribution service for radio terminals present within a service area via a radio section, comprising:

• informing control means for informing all the radio terminals present within the service area of information for identifying multicast information on distribution service and radio channels including at least one frequency number used for distributing the multicast information by using a single message sent on a predetermined radio channel,
• each of the radio terminals present within the service area being able to receive the multicast information distribution service via the thus-informed radio channels.

A radio terminal which receives multicast information distribution service via a radio section from an information distributing apparatus, comprising:

• service state reception control means receiving a single message from the information distributing apparatus management information indicating correspondence relationship between information for identifying multicast information on distribution service and radio channels including at least one frequency number used for distributing the multicast information, and
• receiving from the information distributing apparatus the desired multicast information distribution service via the corresponding radio channels based on the management information received by the service state reception control means in the single message.

A multicast service providing method by which multicast data is distributed to radio terminals from a radio base station, wherein:

• the radio terminal which receives the multicast data transmits a distribution request for multicast data to a radio base station on movement destination in case a necessity arises such that the other party of communication be switched from a radio base station on movement origin to the radio base station on movement destination,
• the radio base station on movement destination transmits information of a radio channel used for distributing the multicast data to the radio terminal in response to the distribution request given therefrom, and
• the radio terminal switches the radio channel based on the information of the radio channel given by the radio base station on movement destination and receives the multicast data from the radio base station on movement destination.

A radio base station which transmits multicast data to a radio terminal, comprising:

• distribution request receiving means receiving a distribution request for multicast data transmitted from the radio terminal, and
• radio channel information transmitting means transmitting information of a plurality of radio channels including at least one frequency number used for distributing the multicast data in a single message in response to the distributing request for the multicast data given by the radio terminal.

A radio terminal which receives multicast data distributed by a radio base station, comprising:

• distribution request transmitting means transmitting a distribution request for multicast data to a radio base station on movement destination in case a necessity arises such that the other party of communication be switched from a radio base station on movement origin to the radio base station on movement destination, and
• multicast data reception control means for switching a radio channel based on information concerning a radio channel used for distributing the multicast data transmitted from the radio base station on movement destination in response to the distribution request so as to receive the multicast data distributed from the radio base station on movement destination.