A new way of extending network coverage: Relay-assisted D2D communications in 3GPP

Wireless relaying in cellular networks has attracted considerable attention because of its capability of extending coverage and improving transmission reliability. The Third Generation Partnership Project (3GPP) had standardized the relaying functionality in Release 10. In Release 13, the concept of relaying has been evolved to combine it with device-to-device communications for extending network coverage further. In this paper, a state-of-the-art 3GPP relay technology called the UE-to-Network relay that provides a novel approach of extending network coverage will be introduced briefly.