Energy efficiency analysis in device-to-device communication underlaying cellular networks

In this paper, the energy efficiency (EE) is focused and analyzed in device-to-device (D2D) communication underlaying cellular networks when the resources are shared by D2D and cellular users in three modes, namely, Non-Orthogonal Sharing mode (NOS), Orthogonal Sharing mode (OS), and Cellular Mode (CM). In addition, energy efficient power allocation schemes in the three modes are given under the maximum transmission power constraint. Numerical simulations are performed in a single-cell environment and the EE performance in these modes are simulated by varying three system parameters: a) the distance between D2D users, b) the distance between the D2D pair and the Base Station (BS), c) the location of the cellular user. The results demonstrate that the cross effect of the EE between NOS and OS exists and it is more preferable that the D2D users communicate with each other directly in terms of the EE.