Peer-to-peer link security setup for relay connection to mobile network

A first user equipment, comprising:

• a peer-to-peer wireless interface to communicate with other wireless devices;
• and
• a processing circuit coupled to the wireless interface, the processing circuit configured to identify a second user equipment that can communicate via the peer-to-peer wireless interface and serve as a relay to a mobile network node,
• obtain a relay session key material from the mobile network node,
• establish or modify a peer-to-peer communication link with the second user equipment, the peer-to-peer communication link secured based on the relay session key material,
• establish, over the peer-to-peer communication link, a protocol data unit session with the mobile network node, and further comprising:
• send a message to the mobile network node via the mobile network interface, the message including a relay identifier for the second user equipment, and
• receive the relay session key material from the mobile network node in response to the message, wherein the relay session key material is a function of the relay identifier.

A method operational at a first user equipment, the method comprising:

• establishing a network communication link with a mobile network node;
• establishing a peer-to-peer communication link with a second user equipment;
• obtaining a relay session key material generated by the mobile network node;
• securing the peer-to-peer communication link based on the relay session key material;
• relaying, over the peer-to-peer communication link, a protocol data unit session between the second user equipment and the mobile network node;
• and
• wherein the peer-to-peer communication link is established prior to the relay session key material being obtained, and the method further comprising:
• relaying a message, on behalf of the second user equipment, to the mobile network node via the peer-to-peer communication link, the message including a relay identifier for the first user equipment;
• receiving the relay session key material from the mobile network node in response to the message;
• and
• securing the peer-to-peer communication link based on the relay session key material.

A first user equipment, comprising:

• a mobile network interface to communicate with a mobile network node;
• a peer-to-peer wireless interface to communicate with other wireless devices;
• and
• a processing circuit coupled to the wireless interface, the processing circuit configured to:
• establish a network communication link with the mobile network node;
• establish a peer-to-peer communication link with a second user equipment;
• obtain a relay session key material generated by the mobile network node;
• secure the peer-to-peer communication link secured based on the relay session key material;
• relay, over the peer-to-peer communication link, a protocol data unit session between the second user equipment and the mobile network node;
• and
• wherein the peer-to-peer communication link is established prior to the relay session key being obtained, and the processing circuit is further configured to:
• relaying a message, on behalf of the second user equipment, to the mobile network node via the peer-to-peer communication link, the message including a relay identifier for the first user equipment;
• receiving the relay session key from the mobile network node in response to the message;
• and
• securing the peer-to-peer communication link based on the relay session key.