Procedures enabling v2x unicast communication over pc5 interface

A method performed by a first wireless transmit/receive unit (WTRU) for establishing a communication link, the method comprising:

• receiving a first message from a second WTRU, wherein the first message indicates a request to communicate with the second WTRU;
• sending a second message to the second WTRU, the second message indicating a first set of least significant bits (LSBs) associated with the second WTRU;
• receiving a third message from the second WTRU indicating whether the first set of LSBs is rejected or accepted;
• and wherein
• if the first set of LSBs is accepted, receiving a security key identifier using a set of generated most significant bits (MSBs) associated with the second WTRU and the first set of LSBs associated with the first WTRU, and sending a fourth message to the second WTRU using a secure communication link associated with the security key identifier, or
• if the first set of LSBs is rejected, sending a fifth message to the second WTRU indicating a second set of LSBs that is associated with the first WTRU.

A first wireless transmit/receive unit (WTRU) comprising:

• A processor configure to
• receive a first message from a second WTRU, wherein the first message indicates a request to communicate with the first WTRU;
• send a second message to the second WTRU, the second message indicating a first set of least significant bits (LSBs) that is associated with the first WTRU;
• receive a third message from the second WTRU rejecting the first set of LSBs;
• send a fourth message to the second WTRU, the fourth message indicating a second set of LSBs that is associated with the first WTRU, and
• receive a fifth message from the second WTRU using a secure communication link based on a first security key identifier, the first security key identifier based on a set of generated most significant bits (MSBs) associated with the second WTRU and the second set of LSBs associated with the first WTRU.

A method performed by a first wireless transmit/receive unit (WTRU) comprising:

• receiving a first message from a second WTRU, wherein the first message indicates a request to communicate with the first WTRU;
• sending a second message to the second WTRU, the second message indicating a first set of least significant bits (LSBs) that is associated with the first WTRU;
• receiving a third message from the second WTRU rejecting the first set of LSBs;
• sending a fourth message to the second WTRU, the fourth message indicating a second set of LSBs that is associated with the first WTRU, and
• receiving a fifth message from the second WTRU using a secure communication link based on a first security key identifier, the first security key identifier based on a set of generated most significant bits (MSBs) associated with the second WTRU and the second set of LSBs associated with the first WTRU.