A geometrical-based throughput bound analysis for device-to-device communications in cellular networks

Abstract

Abstract—Device-to-device (D2D) communications in cellular networks are promising technologies for improving network throughput, spectrum efficiency, and transmission delay. In this paper, we first introduce the concept of guard distance to explore a proper system model for enabling multiple concurrent D2D pairs in the same cell. Considering the Signal to Interference Ratio (SIR) requirements for both macro-cell and D2D communications, a geometrical method is proposed to obtain the guard distances from a D2D user equipment (DUE) to the base station (BS), to the trans-mitting cellular user equipment (CUE), and to other communicat-ing D2D pairs, respectively, when the uplink resource is reused. By utilizing the guard distances, we then derive the bounds of the maximum throughput improvement provided by D2D communi-cations in a cell. Extensive simulations are conducted to demon-strate the impact of different parameters on the optimal maximum throughput. We believe that the obtained results can provide useful guidelines for the deployment of future cellular networks with underlaying D2D communications. Index Terms—Device-to-device (D2D) communications, uplink reuse, throughput, guard distances, circle packing. I.