Telecommunications apparatuses and methods

A terminal for use in a mobile telecommunications system and for using a relay node as a terminal-to-terminal relay for device-to-device (D2D) communication between the terminal and a second terminal, the terminal comprising:

• a transceiver;
• and
• processing circuitry configured to
• determine that a quality for the D2D communication with the second terminal is below a threshold, and
• control, after determining that signal quality for the D2D communication with the second terminal is below the threshold, the transceiver to transmit a relay request to the relay node, wherein
• the second terminal does not transmit another relay request to the relay node,
• in response to transmitting the relay request, the transceiver receives from the relay node one or more grant messages, the one or more grant messages notifying the terminal of an identification of the relay node and of resources allocated for the relay node to relay the D2D communication with the second terminal, and
• the processing circuitry is further configured to
• control the transceiver to exchange messages with the second terminal via the relay node and using the allocated resources for the D2D communication, and
• perform D2D communication with a third terminal without relaying messages via the relay node in a case that the a signal quality for the D2D communication between the first terminal and the third terminal is at or above the threshold.

A method of allocating resources in a mobile telecommunications system, the resources being for a relay node to operate as a terminal-to-terminal relay for device-to-device (D2D) communication between a first terminal and a second terminal, the method comprising:

• in a case that the first terminal determines that a signal quality for the D2D communication between the first terminal and the second terminal is below a threshold, receiving, by the relay node, a relay request directed to the relay node and sent by the first terminal without receiving another relay request from the second terminal;
• identifying, by the relay node, a resource pool for terminal-to-terminal relaying;
• allocating, in response to receiving the relay request without receiving another relay request from the second terminal, first resources from the resource pool for the first terminal to communicate via the relay node for the D2D communication with the second terminal;
• allocating, in response to receiving the relay request without receiving the another relay request from the second terminal, second resources from the resource pool for the second terminal to communicate via the relay node for the D2D communication with the first terminal;
• transmitting, by the relay node, one or more grant messages to the first and second terminals, the one or more grant messages indicating an identification of the relay node and the allocated first and second resources;
• and
• relaying messages, via the relay node and over the first and second resources, between the first and second terminals for the D2D device communication, wherein
• the first terminal performs other D2D communication with a third terminal without relaying messages via the relay node in a case that the a signal quality for the other D2D communication between the first terminal and the third terminal is at or above the threshold.