Reliable and Secure Transmission in Multiple Antennas Hybrid Satellite-Terrestrial Cognitive Networks Relying on NOMA

Abstract

We study a hybrid satellite-terrestrial cognitive network (HSTCN) relying on non-orthogonal multiple access (NOMA) interconnecting a satellite and multiple terrestrial nodes. In this scenario, the long distance communication is achieved by the satellite equipped multiple antennas to send information to a multi-antenna destinations through the base station acting as relay. The secure performance is necessary to study by exploiting the appearance of an eavesdropper attempting to intercept the transmissions from relay to destinations. We explore situation of hardware imperfections in secondary network and deign of multiple antennas need be investigated in term of the physical-layer security by adopting the decode-and-forward (DF) relay strategy. Specifically, we guarantee coverage area by enabling relaying scheme and keep outage probability (OP) performance satisfying required data rates. Moreover, suppose that only the main channels' state information is known while the wiretap channels' state information is unavailable due to the passive eavesdropper, we analyze the secrecy performance in term of intercept probability (IP) of the HSTCN by driving the closed-form expressions of such performance metric. Finally, the presented simulation results show that: 1) The outage behaviors of NOMA-based HSTCN network does not depend on transmit signal to noise ratio (SNR) at source at high SNR; 2) Numerical results show that the such system using higher number of transceiver antennas generally outperform the system with less antennas in terms of OP and IP and reasonable selection of parameters is necessary to remain the secrecy performance of such systems; and 3) By allocating different power levels to tow users, the second user has better secure behavior compared with the first user regardless of other set of satellite links or the number of antennas, which means that the superiority of the second user compared with user the first user in terms of OP and IP are same. INDEX TERMS hybrid satellite-terrestrial cognitive systems, outage probability, Shadowed-Rician fading

Robust Secure Beamforming Design for Cooperative Cognitive Radio Nonorthogonal Multiple Access Networks

“…Secure communication is also a critical issue for cooperative CR NOMA networks. Recently, physical layer security has been proposed in [21][22][23][24][25][26][27] for cooperative CR NOMA networks, where the security performance of communication networks can be greatly improved by the cooperation of the relay node (i.e., SU). e authors in [21] studied the physical layer security in a cooperative CR NOMA network where all the nodes had a single antenna and the SU employed amplify-and-forward (AF) relaying to forward the PU's signal, aiming to analyze the security performance of the PU and throughput of the SU.…”

“…In the study by She et al [23], the authors investigated the optimization of power allocation and transmit covariance matrix to improve the security energy efficiency of the SU for a DF-relaying cooperative CR NOMA network. e works [25][26][27] also focused on the DFrelaying cooperative CR NOMA network in order to analyze the security performance of the network.…”

“…Most existing works for physical layer security in cooperative CR NOMA networks consider the analysis of the security performance, e.g., [21,[24][25][26][27], but only few works consider the physical layer security optimization, e.g., [22,23]. Besides, physical layer security optimization for conventional cooperative CR NOMA networks is investigated in [28].…”

“…Note that our work is very different from the previous works in [21][22][23][24][25][26][27][28]. First, we assume that the CSI of the eavesdropper is imperfect, which is more practical than the assumption of the perfect CSI in [21][22][23][24][25][26][27][28]. Second, we focus on the optimization design to improve the security performance, while [21] and [24][25][26][27] just provide the analysis of the security performance.…”

“…First, we assume that the CSI of the eavesdropper is imperfect, which is more practical than the assumption of the perfect CSI in [21][22][23][24][25][26][27][28]. Second, we focus on the optimization design to improve the security performance, while [21] and [24][25][26][27] just provide the analysis of the security performance. ird, we propose a global optimal solution for the secure optimization problem, while only suboptimal solutions are provided in [22,23].…”