Abstract: A relay selecting apparatus (1, 3 or 5) is configured to select at least one specific relay terminal (2) suitable for a remote terminal (1) from among one or more relay terminals (2) based on a selection criterion that considers a time variation of a device-to-device (D2D) link quality between the remote terminal (1) and each of the one or more relay terminals (2). In this way, it is possible to contribute to improving a relay selection so as to provide a stable relay quality.

Abstract: A D2D communication control apparatus (10) according to the present invention includes: a communication unit (11) configured to receive determination information that can be used to determine whether each of a plurality of radio terminals is capable of performing device-to-device (D2D) communication with another radio terminal; and a selection unit (12) configured to select, using the determination information between radio terminals that may operate as relay radio terminals, a candidate for a relay radio terminal that relays the communication between one of the plurality of radio terminals and a network, the relay radio terminal candidate transmitting a response signal in response to a first discovery signal transmitted from one of the radio terminals by performing D2D communication with the one of the plurality of radio terminals and performing cellular communication with the network.

Abstract: A wireless terminal apparatus (2) is configured, before the wireless terminal apparatus (2) is requested by another wireless terminal (1) or a D2D controller (5) to start a relay operation between the other wireless terminal (1) and the cellular network (3, 4), to hold connection information necessary to allow the other wireless terminal (1) to communicate with the cellular network (3, 4) or with a node (7) in an external network (6) via the relay operation performed by the wireless terminal apparatus (2). It is thus, for example, possible to contribute to reducing latency from when a mobile relay is requested to start a relay operation until the relay operation can be started.