Coalition formation based energy efficient spectrum leasing in doubtful inband cooperative D2D communications

In this paper, we investigate an inband cooperative device-to-device (D2D) communication system in cellular networks. Cellular users and D2D pairs help each other to improve their respective performance. Specifically, via coalition formation, cellular users release some of their spectrum to D2D pairs so as to start the communications of the D2D pairs; at the same time, D2D pairs help to relay the messages of the cellular users. The D2D pairs are thought to be socially untrusted to the cellular users, as thus, a secrecy problem for cellular users comes into being due to the relaying. Then we address this problem from a physical layer security perspective. A coalition formation algorithm is designed to solve the spectrum management problem in this cooperative system. Numerical results show the validity of the proposed scheme.