| 摘要 |
This mobile communication system includes a base station, a first user terminal and second user terminal that establish a connection with the base station, and a core network that encompasses the base station. This mobile communication system supports cellular communication in which the data path set between the first user terminal and the second user terminal goes through the core network, and D2D communication in which the data path does not go through the core network. The D2D communication includes a first D2D communication mode in which the data path does not go through the base station, and a second D2D communication mode in which the data path does go through the base station. If the communication state of the D2D communication by the first D2D communication mode deteriorates, then, after transitioning to the second D2D communication mode and sending unsent data, the first user terminal and the second user terminal switch from the D2D communication to the cellular communication. |
