Information theoretic secrecy for some multiuser wireless communication channels

Xiaoying Qiu, Ting Jiang

In this paper, we consider secure communications in a multiuser wireless network, where full-duplex (FD) users operate to enhance wireless physical layer security. Under these assumptions, we exploit the user selection scheme to strengthen the secure performance. We first analyze the optimal power allocation strategy with the knowledge of instantaneous channel state information (CSI) of every channel. We then investigate the security level of the proposed scheme through the ergodic secrecy rate (SR) and secrecy outage probability with only the statistical knowledge of CSIs. Simulation results show that the application of user selection and FD communication lead to a significant improvement in wireless communication security.

Şennur Ulukuş, Ersen Ekrem

Alex Reznik, Yogendra Shah, Laura Luzzi +1 more

G. Prema, R. Sowmini

Multiuser multiple-input multiple-output (MIMO) wireless techniques have received tremendous attention as a way to achieve high spectral efficiency in current mobile communication systems such as Long Term Evolution (LTE) [1]. Due to the broadcast nature of the physical medium, wireless multiuser communications are very susceptible to eavesdropping, and it is critical to secure the transmitted information. In this work, consider the broadcast channel with confidential messages and external eavesdroppers (BCCE), where a multi-antenna base station [2] simultaneously communicates to multiple potentially malicious users, in the presence of randomly located external eavesdroppers. The secrecy capacity is measured in terms of outage probability and provides a complete characterization of the maximum transmission rate at which the eavesdropper is unable to decode any information. Using the proposed model, the secrecy rates is achieved with regularized channel inversion (RCI) precoding and analyzed by performing a large-system analysis where the number of users K and the number of transmit antennas N both grow to infinity in a fixed ratio. Finally an explicit expression for the probability of secrecy outage and the system performance is analyzed in the presence of both colluding and non-colluding eavesdroppers.

Hyoungsuk Jeon, Namshik Kim, Jinho Choi +2 more

We consider a physical layer security based on the wiretap channel for wireless communication systems in which there are one transmitter and multiple receivers/users who report their channel state information (CSI) to the transmitter. This scenario is practically useful since it models the forward link of cellular systems where the systems can take advantage of the multiuser diversity. We are curious about the role of the multiuser diversity in the secure communication under the wiretap channel framework. Although it is well known that fixed transmit power is not optimal when CSI is available to the transmitter, to get useful insights, we consider a fixed transmit power case. In return, we can have some of important performance measures such as outage probability, average secrecy rate, failure rate, and average wait time in closed forms. The analysis interestingly shows that the multiuser diversity becomes always disadvantageous for the secure communications. We substantiate our claims with the analytic results and numerical evaluations.

Ersen Ekrem, Şennur Ulukuş