Analysis of Area Spectral Efficiency in D2D Underlaid Downlink Cellular Networks

Abstract

From the perspective of statistical performance, this paper presents an analytical framework to handle the mutual interference between cellular networks and Device-to-Device (D2D) pairs in D2D underlaid downlink cellular networks. We assume that the D2D transmitters adopt power control and the base stations (BSs) adopt zero-forcing beamforming (ZFBF) to suppress the mutual interference. Using stochastic geometry, we derive the expressions for the coverage probability and the average data rate of users. Based on the analytical results, we discuss the optimal values of some important parameters to maximize the system area spectral efficiency (ASE) while guaranteeing the quality-of-service (QoS) of users, i.e., the coverage probability of users is above a threshold. The result shows that power control at D2D is always suboptimal for system ASE when the density of BSs is large enough.