Dterminal device having a relay function and method of providing information related to a relay function

A communication system comprising:

• a terminal device comprising:
• a wireless cellular interface configured for communication with a radio access network of an associated cellular communication network;
• and
• a circuit controlling the wireless cellular interface;
• and
• an other terminal device comprising:
• a further wireless cellular interface configured for communication with the radio access network of the associated cellular communication network;
• and
• a further circuit controlling the further wireless cellular interface,
• the circuit controlling the wireless cellular interface of the terminal device being operative to:
• receive a request from the other terminal device;
• in response to receiving the request from the other terminal device, transmit at least one message to the other terminal device, the at least one message comprising security-related information of the terminal device;
• receive a further request from the other terminal device;
• and
• activate a relay function of the terminal device to start relaying communication between the other terminal device and the radio access network of the associated cellular communication network,
• the circuit controlling the wireless cellular interface of the other terminal device being operative to:
• transmit the request to the terminal device;
• in response to receiving the at least one message from the terminal device, transmit the further request to the terminal device;
• and
• activate a relay function to start the communication with the radio access network of the associated cellular communication network via the terminal device.

A method of providing a relay function in a terminal device comprising a wireless cellular interface configured for communication with a radio access network of an associated cellular communication network, and a circuit controlling the wireless cellular interface, the method comprising:

• receiving at the wireless cellular interface of the terminal device a request from a requesting other terminal device of a plurality of other terminal devices;
• in response to receiving the request from the requesting other terminal device, transmitting by the wireless cellular interface of the terminal device at least one message to the requesting other terminal device, the at least one message comprising security-related information of the terminal device;
• receiving at the wireless cellular interface of the terminal device a further request from the requesting other terminal device;
• and
• in response to receiving the further request from the requesting other terminal device, activating a relay function of the terminal device to start relaying communication between the requesting other terminal device and the radio access network of the associated cellular communication network.

A terminal device for wireless communication, the terminal device comprising:

• a wireless cellular interface configured for communication with a radio access network of an associated cellular communication network;
• and
• a circuit controlling the wireless cellular interface, the circuit operative to:
• receive an announcement message from a plurality of other terminal devices;
• in response to receiving the announcement message from the plurality of other terminal devices, transmit a request to the plurality of other terminal devices;
• receive from two or more of the plurality of other terminal devices two or more messages comprising security-related information of the two or more of the plurality of other terminal devices;
• in response to receiving the two or more messages, select a most suitable terminal device from amongst the two or more of the plurality of other terminal devices as a relay;
• and
• in response to selecting the most suitable terminal device, transmit a further request to the selected most suitable terminal device,
• wherein in response to activating a relay function at the selected terminal device, communication between the terminal device and the radio access network is relayed through the selected terminal device.