A wireless communication apparatus comprising: a communicator (no) arranged to transmit and receive data, wherein the communicator (no) is arranged to receive data from an external transmitter and transmit the data to a first receiver and a second receiver , and a controller arranged to control the communicator (no) to receive the data and destination information of the first receiver and the second receiver about the transmission of the data and a request of unicast service for multicast from the external transmitter , wherein the controller is further arranged to control the communicator to: transmit a request for unicast transmission to the first receiver; transmit a request to snoop unicast data transmitted to the first receiver to the second receiver; transmit, by unicast transmission, the received data and the received destination information about the transmission of the data to the first receiver when it the data is received from the external transmitter, wherein the controller is further arranged to control the communicator to receive a response signal about acknowledgement or a response signal about error in receiving the data from at least one receiver among the first receiver and the second receiver; and wherein the controller is further arranged to control the communicator to retransmit the data to the at least one receiver among the first receiver and the second receiver which sent the response signal about error in receiving the data. a communicator (no) arranged to transmit and receive data, wherein the communicator (no) is arranged to receive data from an external transmitter and transmit the data to a first receiver and a second receiver , and a controller arranged to control the communicator (no) to receive the data and destination information of the first receiver and the second receiver about the transmission of the data and a request of unicast service for multicast from the external transmitter , wherein the controller is further arranged to control the communicator to: transmit a request for unicast transmission to the first receiver; transmit a request to snoop unicast data transmitted to the first receiver to the second receiver; transmit, by unicast transmission, the received data and the received destination information about the transmission of the data to the first receiver when it the data is received from the external transmitter, wherein the controller is further arranged to control the communicator to receive a response signal about acknowledgement or a response signal about error in receiving the data from at least one receiver among the first receiver and the second receiver; and wherein the controller is further arranged to control the communicator to retransmit the data to the at least one receiver among the first receiver and the second receiver which sent the response signal about error in receiving the data. transmit a request for unicast transmission to the first receiver; transmit a request to snoop unicast data transmitted to the first receiver to the second receiver; transmit, by unicast transmission, the received data and the received destination information about the transmission of the data to the first receiver when it the data is received from the external transmitter, wherein the controller is further arranged to control the communicator to receive a response signal about acknowledgement or a response signal about error in receiving the data from at least one receiver among the first receiver and the second receiver; and wherein the controller is further arranged to control the communicator to retransmit the data to the at least one receiver among the first receiver and the second receiver which sent the response signal about error in receiving the data. <EOS>