USER EQUIPMENT, COMMUNICATION SYSTEM, AND BACKOFF CONTROL METHOD

摘要

A user apparatus having a function for performing device-to-device communication by radio, including: a resource state detection unit configured to detect a state of each resource in a set of resources that can be used for device-to-device communication; a backoff control unit configured, when the state detected by the resource state detection unit satisfies a predetermined condition, to set the user apparatus to be in a backoff state in which the user apparatus does not perform transmission of a discovery signal for a predetermined period; and a discovery signal transmission unit configured, when the user apparatus is not in the backoff state, to select a resource from among the set of resources, and to transmit a discovery signal using the selected resource.