Secrecy performance analysis in large-scale cellular networks via stochastic geometry

In this paper, we study secrecy performance of downlink transmission in large-scale cellular networks where randomly distributed Base Stations (BSs) communicate to an intended mobile user under the scenario of cooperative eavesdropping. Based on the stochastic geometry theory, we first derive the closed-form expressions of the secrecy outage probability and the average secrecy rate in the simple scenario of non-cooperative eavesdropping, where each eavesdropper decodes the messages independently. Then, the secrecy performance analysis is extended to more hazardous cooperative scenario in which all eavesdroppers freely share their observations to decode the confidential messages. Finally, our results show that the small-scale fading has a greater effect on secrecy performance in small density of eavesdroppers. Moreover, the performance difference between the scenario of non-cooperative eavesdropping and cooperative eavesdropping is more obvious, when the path loss exponent or the density of eavesdroppers is small.