Base station and user terminal, for transmitting and receiving multicast data using semi-persistent scheduling

1. A base station configured to manage a cell in which a group including a plurality of first user terminals and a second user terminal, which is different from the plurality of first user terminals, exists, comprising:

a controller configured to instruct, if starting transmission of multicast data to the plurality of first user terminals, each of the plurality of first user terminals to activate a semi-persistent scheduling; and

a transmitter configured to use the semi-persistent scheduling to transmit the multicast data to the plurality of first user terminals via a physical downlink shared channel, wherein

the transmitter is configured to

after instructing each of the plurality of first user terminals to perform the activation of the semi-persistent scheduling, transmit a message including configuration information about a configuration of the semi-persistent scheduling and activation notification information indicating that the semi-persistent scheduling is activated, to the second user terminal.

2. The base station according to claim 1 , wherein the activation is instructed via the physical downlink control channel, and

the controller is configured to repeatedly instruct a user terminal in the group to perform the activation.

3. The base station according to claim 1 , wherein the controller is configured to instruct a user terminal in the group to perform the activation, even after starting transmitting the multicast data.

4. The base station according to claim 2 , wherein the controller is configured to regularly instruct the user terminal in the group to perform the activation.

5. The base station according to claim 1 , wherein the message is a broadcast RRC message, an individual RRC message, or a MAC message.

6. A base station configured to manage a cell in which a group including a plurality of first user terminals and a second user terminal, which is different from the plurality of first user terminals, exists, the base station comprising:

a controller configured to instruct, if starting transmission of multicast data to the plurality of first user terminals, each of the plurality of first user terminals to activate a semi-persistent scheduling;

a transmitter configured to use the semi-persistent scheduling to transmit the multicast data to the plurality of first user terminals via a physical downlink shared channel; and

a receiver, wherein

the receiver is configured to receive, from the second user terminal, an interest notification about an interest in receiving the multicast data, after instructing each of the plurality of first user terminals to activate the semi-persistent scheduling, and

the transmitter is configured to transmit, to the second user terminal, a message including configuration information about a configuration of the semi-persistent scheduling and activation notification information indicating that the semi-persistent scheduling is activated, if receiving the interest notification after instructing each of the plurality of first user terminals to activate the semi-persistent scheduling.

7. A second user terminal belonging to a group including a plurality of first user terminals and the second user terminal, which is different from the plurality of first user terminals, the second user terminal comprising:

a transmitter configured to transmit, to a base station, an interest notification about an interest in reception of multicast data, after an activation instruction for semi-persistent scheduling is sent to each of the plurality of first user terminals by the base station;

a receiver configured to receive, from the base station, after transmitting the interest notification, a message including configuration information indicating a configuration of the semi-persistent scheduling and activation notification information indicating that the semi-persistent scheduling is activated; and

a controller configured to, based on the configuration information and the activation notification, activate the semi-persistent scheduling at the second user terminal, wherein

the receiver is configured to use the semi-persistent scheduling to receive the multicast data transmitted from the base station to the plurality of first user terminals and the second user terminal, via a physical downlink shared channel.

8. The user terminal according to claim 7 , wherein the message is a broadcast RRC message, an individual RRC message, or a MAC message.