Device-to-Device Communication(D2D) is a hybrid radio technology that supports direct communication between closely spaced mobile devices as well as direct communication between two devices within a radio cell. Direct communication takes place without a base station and without a route through the network infrastructure.
Direct radio transmission between neighboring devices enables proximity services ( ProSe) to be implemented over distances of around 500 meters. This technology improves spectrum utilization, overall throughput and energy efficiency, while enabling new location-based services( LBS) and proximity services. The functional interface implemented in LTE handsets is called Sidelink.
Device-to-device communication (D2D) facilitates interoperability between critical public and commercial mobile networks such as Long Term Evolution (LTE).
As for D2D technology, 3GPP has taken up the research of some universities and addressed the issue in LTE-A under Release 12. An important aspect for D2D networks is resilience. Even in the event of a mobile network failure, D2D networks can act as back-up networks.
Other advantages of D2D technology include an increase in transmission capacity, since this is shared by direct radio transmission and the cellular network, an increase in the data rate, and reduced latency, all when mobile devices communicate directly with each other.