Traditionally, in wireless communication networks, terminal devices, such as user equipment (UE) are addressed by the network through individual identifiers (IDs), which are used to create individual communication channels between the network and UEs. The UE is any device used directly by an end-user to communicate. For example, the UE can be a hand-held telephone, a laptop computer equipped with a mobile broadband adapter, or any other user communications device. Recently, cooperative multi-point (CoMP) transmission/reception, where multiple E-UTRAN Node-Bs (eNBs) cooperate to transmit data to UEs, has received attention and is currently being integrated in the 3GPP standard. UE cooperation based on device-to-device (D2D) communications is another technology that has received less attention in comparison. However, with the advances in (D2D) communications in recent years, UE cooperation is expected to play a more prominent role in the future of wireless communications.