Mobile communication system, user terminal, and processor
A UE 100 - 1 and a UE 200 - 2 perform D2D communication that is direct device to device communication. The UE 100 - 1 transmits a D2D termination preliminary notification indicating that termination of the D2D communication is wished to the UE 100 - 2 during the D2D communication. The UE 100 - 1 terminates the D2D communication after transmitting the D2D termination preliminary notification.
1. A first user terminal, comprising:
a controller configured to perform a direct device-to-device communication with a second user terminal for communicating user data; and
a transmitter configured to transmit, to the second user terminal, a preliminary notification for a termination of the direct device-to-device communication, wherein
the controller is further configured to:
continue the direct device-to-device communication if the first user terminal receives a response to the preliminary notification before terminating the direct device-to-device communication after starting the direct device-to-device communication; and
terminate the direct device-to-device communication if the first user terminal does not receive the response until a predetermined period has elapsed after transmission of the preliminary notification.
2. The first user terminal according to claim 1 , wherein
the controller is further configured to start a timer in response to the transmission of the preliminary notification, and
the timer is used for counting the predetermined period.
3. The first user terminal according to claim 1 , wherein the transmitter is further configured to transmit the preliminary notification in response to having no data to be transmitted to the second user terminal by the direct device-to-device communication.
4. A processor for controlling a first user terminal, configured to:
control a direct device-to-device communication with a second user terminal for communicating user data;
transmit, to the second user terminal, a preliminary notification for a termination of the direct device-to-device communication;
continue the direct device-to-device communication if the first user terminal receives a response to the preliminary notification before terminating the direct device-to-device communication after starting the direct device-to-device communication; and
terminate the direct device-to-device communication if the first user terminal does not receive the response until a predetermined period has elapsed after transmission of the preliminary notification.
5. The first user terminal according to claim 1 , wherein the transmitter is further configured to transmit, to a base station, a notification for a termination of resource allocation to the first user terminal for the direct device-to-device communication.