Core network device, radio communication base station device, and radio communication method

A radio communication base station apparatus comprising:

• an acquisition section that acquires from a core network apparatus a command for one of multi-cell transmission whereby a plurality of radio communication base station apparatuses belonging to an identical frequency area transfer multimedia broadcast multicast service (MBMS) data in synchronization with each other and single cell transmission whereby a single radio communication base station apparatus accommodating users joining the multimedia broadcast multicast service within a cell transfers the multimedia broadcast multicast service data;
• a counting section that performs counting about a cell under control of the radio communication base station apparatus only when a single cell transmission command is acquired;
• and
• a transfer section that transfers the multimedia broadcast multicast service data in a cell where there are users according to the counting result.

A radio communication terminal apparatus comprising:

• a data decision section that decides whether or not received multimedia broadcast multicast service data is lost and creates, upon deciding that the multimedia broadcast multicast service data is lost, a negative acknowledgment message for requesting a retransmission of the lost multimedia broadcast multicast service data;
• a received power measurement section that measures received power in each neighboring cell;
• and
• a transmission section that transmits the negative acknowledgment message and received power measurement result in each neighboring cell to a radio communication base station apparatus.

A radio communication method comprising:

• counting, by a core network apparatus, a number of users joining a multimedia broadcast multicast service (MBMS) on a per tracking area basis;
• comparing, by a core network apparatus, the number of users counted, with a predetermined threshold, so as to select, when the number of users is equal to or greater than the threshold, multi-cell transmission whereby a plurality of radio communication base station apparatuses belonging to an identical frequency area transfer multimedia broadcast multicast service data in synchronization with each other, and select, when the number of users is less than the threshold, single cell transmission whereby a single radio communication base station apparatus accommodating a user joining the multimedia broadcast multicast service within a cell transfers multimedia broadcast multicast service data;
• reporting, by a core network apparatus, one of multi-cell transmission and single cell transmission selected, to radio communication base station apparatuses under control of the core network apparatus;
• acquiring, by a radio communication base station apparatus, a command for one of multi-cell transmission and single cell transmission, from the core network apparatus,
• counting, by a radio communication base station apparatus, about the cell under control of the radio communication base station apparatus only when a single cell transmission command is acquired;
• and
• transferring, by a radio communication base station apparatus, multimedia broadcast multicast service data in a cell where there are users according to the counting result.