Peer discovery for device-to-device (D2D) communication in LTE-A networks

Device-to-device (D2D) communication is one of the key technologies in Long Term Evolution - Advanced (LTE-A) for improving network capacity and resource utilization. D2D communication can not only effectively reduce traffic loads to the core network but also reduce power consumption of user equipments (UEs), thus making it a desirable candidate for machine-to-machine communication in cellular networks. Among all functionalities required to enable D2D communication, peer discovery is arguably the most critical one. In this paper, we propose a distributed peer discovery protocol for LTE-A networks. The proposed protocol requires UEs to advertise their presence based on random access. In order to minimize resource consumption on discovery, an adaptive resource allocation algorithm based on the number of requesting D2D UEs is also proposed. Our numerical analysis shows that a very high discovery probability (e.g., 0.99) can be achieved using only 1% of the evolved Node B's (eNB's) uplink resource.