User equipment and device-to-device communication selection method thereof

A device-to-device (D2D) communication selection method for use in a user equipment (UE), the UE comprising a receiving interface, a discovering interface and a selecting interface, the D2D communication selection method comprising:

• (A) receiving D2D communication information by the receiving interface;
• (B) discovering D2D communication nodes by the discovering interface;
• and
• (C) determining by the selecting interface at least one selection procedure from a plurality of selection procedures according to the D2D communication information and selecting at least one first D2D communication target from the discovered D2D communication nodes according to the determined selection procedure;
• wherein the UE further comprises a communication interface, and the D2D communication selection method further comprises:
• (D1) communicating by the communication interface with at least one of the other D2D communication nodes via the first D2D communication target;
• (E1) when the first D2D communication target becomes inactive or has a transmission failure, determining by the selecting interface at least one selection procedure again from the selection procedures according to the D2D communication information and selecting at least one second D2D communication target from the discovered D2D communication nodes according to the determined selection procedure;
• and
• (F1) communicating by the communication interface with the original D2D communication nodes via the second D2D communication target when the first D2D communication target becomes inactive or the transmission fails.