Cooperative beamforming based artificial noise in uplink wiretap channels

Abstract

We propose a cooperative beamforming based artificial noise-aided secure transmission in uplink wiretap channels, where a single user transmits its own data to base station and the others transmits artificial noise to improve the physical layer security. In this study, the cooperative artificial noise and signal-to-interference plus noise ratio (SINR) at the eavesdropper (EV) are analyzed in terms of system (i.e., the total number of users, number of antennas at the base station, and number of antennas at the EV) and design parameters (i.e., the number of beams for generating artificial noise in each user group and the number of user groups). Based on this analysis, the design parameters for uplink secure transmission can be determined to minimize SINR at the EV. Furthermore, the optimal secrecy capacity with EV's channel state information (CSI) is analyzed along with the secrecy capacity without EV's CSI, including the secrecy performance gap between them. Throughout the simulation and numerical results, the analyzed results including asymptotic performance are verified. In addition, it is demonstrated that cooperative artificial noise-aided secure transmission achieves near-optimal secrecy capacity without any CSI on the EV as the number of users increases.