Robust Chance-Constrained Secure Transmission for Cognitive Satellite–Terrestrial Networks

Abstract

Abstract-Cognitive satellite-terrestrial networks (CSTNs) have been recognized as a promising network architecture for addressing spectrum scarcity problem in next-generation communication networks. In this paper, we investigate the secure transmission for CSTNs where the terrestrial base station (BS) serving as a green interference resource is introduced to enhance the security of the satellite link. Adopting a stochastic model for the channel state information (CSI) uncertainty, we propose a secure and robust beamforming framework to minimize the transmit power, while satisfying a range of outage (probabilistic) constraints concerning the signal-to-interference-plus-noise ratio (SINR) recorded at the satellite user and the terrestrial user, the leakage-SINR recorded at the eavesdropper, as well as the interference power recorded at the satellite user. The resulting robust optimization problem is highly intractable and the key observation is that the highly intractable probability constraints can be equivalently reformulated as the deterministic versions with Gaussian statistics. In this regard, we develop two robust reformulation methods, namely S-Procedure and Bernstein-type inequality restriction techniques, to obtain a safe approximate solution. In the meantime, the computational complexities of the proposed schemes are analyzed. Finally, the effectiveness of the proposed schemes are demonstrated by numerical results with different system parameters.

Satellite-Aerial Integrated Computing in Disasters: User Association and Offloading Decision

“…2) Backhaul Uplink: The computation tasks of HAPs may be also offloaded to the LEO satellite via the backhaul uplink due to the placement of enhanced MEC server at the LEO satellite. Different form the G2A and A2A LOS communication links, the air-to-space (A2S) backhaul uplink is determined by a Rician fading channel model with the AWGN [10], [11]. Specifically, the channel fading coefficient between HAP j and the LEO satellite is modeled as a circularly symmetric complex Gaussian random variable, i.e., h j = X 1 +X 2 i, where…”

Secure Transmission Scheme Based on the Artificial Noise in D2D-Enabled Full-Duplex Cellular Networks

“…(6) When the secrecy rates in (4), (5) are positive values, substituting (4) and (5) into (6), we can obtain:…”

“…To overcome this issue, physical-layer security (PLS) [4][5][6][7][8][9] has been recently proposed to employ the opening characters of wireless channels to achieve secret communication, resulting in achieving "absolute" security from the concept of information theory. There has been some work to exploit PLS for D2D communications.…”

Robust Beamforming for Multibeam Satellite Communication in the Face of Phase Perturbations

“…In order to counteract the signal-tointerference and noise ratio (SINR) degradation caused by the CSI estimation error, a robust beamforming has been proposed. There are two types of method invoked for describing the CSI imperfections, namely the so-called determined bounded model [8] and the random model [9]. Specifically, Wang et al [8] maximized the worst-case received SINR by solving a max-min optimization problem under a bounded uncertainty for multi-input multi-output (MIMO) systems, which may not necessarily result in a better convex restrictive approximation.…”

“…However, there is a significant variation in the channel phase component arising out of time varying phase perturbations and the high RTD will induce the outdated CSI [11]. To qualify the service of satellite, Li et al proposed a secure and robust beamforming framework for cognitive satellite-terrestrial networks (CSTNs) to minimize the transmit power under a stochastic model for the CSI uncertainty [9]. However, most of the existing contributions dedicated only limited attention to the phase perturbations induced by a number of impairments, such as the presence of the satellite's non-linear transponders and conditioning filters, the channel fading and the imperfect synchronization caused by the oscillator [13].…”