Patent ID: 8655264

Claim:
A communication system comprising: a unicast base station device that is a base station device that establishes connection to a network which provides a unicast service and a multicast service, and relays information concerning the unicast service; a multicast base station device that is a base station device that establishes connection to the network and relays information concerning the multicast service; and a mobile station device that communicates with the unicast base station device and the multicast base station device, wherein the multicast base station device comprises: a network communication unit; a base station side radio communication unit; and a base station side control unit that controls the network communication unit and the base station side radio communication unit, the mobile station device comprises: a mobile station side radio communication unit; and a mobile station side control unit that controls the mobile station side radio communication unit, the mobile station side control unit controls the mobile station side radio communication unit to transmit identification information to a position registration server in the network via the unicast base station device before the information concerning the multicast service is received from the multicast base station device, the identification information identifying a reception area in which the multicast service is provided, when the network communication unit receives incoming call information addressed to the mobile station device, the base station side control unit controls the base station side radio communication unit to transmit the incoming call information to the mobile station device, the identification information of the mobile station device being registered to the position register server, and the incoming call information indicating that the information concerning the unicast service has been received, and while the information concerning the multicast service is received from the multicast base station device, the mobile station side control unit controls the mobile station side radio communication unit to receive the incoming call information transmitted from the multicast base station device.