Physical Layer Security in Downlink Multi-Antenna Cellular Networks

• Published in: IEEE transactions on communications Vol. 62; no. 6; pp. 2006 - 2021
• Main Authors: Geraci, Giovanni, Dhillon, Harpreet S., Andrews, Jeffrey G., Jinhong Yuan, Collings, Iain B.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.06.2014; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Antennas; Applied sciences; Approximation; Cellular communication; Density; Downlink; Equipments and installations; Exact sciences and technology; Interference; Matrix theory; Messages; Mobile radiocommunication systems; Outages; Physical layer; Probability; Radiocommunications; Secret; Security; Signal to noise ratio; Stations; Stochastic processes; Systems, networks and services of telecommunications; Telecommunications; Telecommunications and information theory; Transmission and modulation (techniques and equipments); Wireless communications; linear precoding; Physical layer security; random matrix theory (RMT); stochastic geometry; cellular networks; Random matrix; Base station; Wireless telecommunication; Downlink; Cell network; Poisson process; Infinite medium; Pretreatment; Safety; Localization; System analysis; Antenna array; Large scale system; Mobile radiocommunication; Outage; Two dimensional model; Channel coding; Electrical network; Point process; Telecommunication network; Secrecy
• ISSN: 0090-6778; 1558-0857
• DOI: 10.1109/TCOMM.2014.2314664

In this paper, we study physical layer security for the downlink of cellular networks, where the confidential messages transmitted to each mobile user can be eavesdropped by both; 1) the other users in the same cell and 2) the users in the other cells. The locations of base stations and mobile users are modeled as two independent two-dimensional Poisson point processes. Using the proposed model, we analyze the secrecy rates achievable by regularized channel inversion (RCI) precoding by performing a large-system analysis that combines tools from stochastic geometry and random matrix theory. We obtain approximations for the probability of secrecy outage and the mean secrecy rate, and characterize regimes where RCI precoding achieves a non-zero secrecy rate. We find that unlike isolated cells, if one treats interference as noise, the secrecy rate in a cellular network does not grow monotonically with the transmit power, and the network tends to be in secrecy outage if the transmit power grows unbounded. Furthermore, we show that there is an optimal value for the base station deployment density that maximizes the secrecy rate, and this value is a decreasing function of the transmit power.