Analysis of device-to-device communications with exclusion regions underlaying 5G networks

Device-to-device (D2D) communication underlaying cellular networks is an effective way to improve spectral efficiency and alleviate the traffic load of base stations, therefore it is considered as one of the key technologies in the fifth generation mobile communications, also referred to as IMT-2020. However, it also introduces interference between D2D terminals and cellular users. In this work, we adopt both exclusion regions (ERs) and open-loop fraction power control (OFPC) to mitigate the D2D-to-Cellular interference in a multicell uplink spectrum-sharing scenario. We derive the closed-form expressions of outage probability (OP) and area spectral efficiency (ASE) using stochastic geometry, and reveal the impact of the D2D user equipment (DUE) density versus cellular user equipment (CUE) density (in other words, how many DUEs can reuse the resource of a CUE per cell), D2D communication distance, different ER sizes, and of the compensation factor in OFPC. Numerical results show that adopting ERs could both decrease the OP of cellular users and increase the network ASE, and a proper ER radius can be selected by network operators according to their target OP, D2D users' density, and the communication distance of D2D users.