Analysis of Device-to-Device discovery and link setup in LTE networks

Device-to-Device (D2D) communications allow devices to communicate directly without going through infrastructure. It is considered a promising solution to improve communication performance and network capacity of LTE-Advanced system. From the perspective of User Equipment (UE), additional energy consumption is required to support D2D communications. In addition, recent device supports multiple Radio Access Technologies (RATs) with high energy consumption. For an energy efficient D2D communication, the most significant problem is how to detect proximal devices and to establish a D2D link in a timely manner. In this paper, we propose a D2D discovery and link setup procedure, and analyze its performance in terms of energy consumption and delay by utilizing the measurement results with real LTE smartphones. Based on the analysis results, we conclude that there is a trade-off relation between energy consumption and delay performance.