Abstract: A technique that can effectively utilize unused wireless link and realize high-quality wireless communication between a communication terminal and a base station and enables efficient distribution of radio resources over an entire wireless communication system is provided. A wireless communication system in which a base station and a communication terminal can conduct wireless communication by detecting a usable wireless link and changing a wireless link used for the connection is also provided. On the communication network side, in addition to a plurality of wireless communication networks and a base station, a server device is provided.