Physical Layer Security in NOMA-Enabled Cognitive Radio Networks With Outdated Channel State Information

Abstract

In this paper, we investigate physical layer security (PLS) in non-orthogonal multiple access-enabled (NOMA-enabled) underlay cognitive radio networks (CRNs) with outdated channel state information (CSI). Considering the influence of outdated CSI on the interference of secondary transmitter (Alice) to primary user (PU), the constraint for the power is adopted to guarantee the quality-of-service (QoS) of PU over Nakagami-m channels. To further analyze the NOMA-enabled underlay CRNs with outdated CSI in PLS perspective, the secrecy performance is evaluated by the closed-form expressions for connection outage probability (COP), the intercept probability (IP) and effective secrecy throughput (EST). In addition, Monte Carlo simulations are provided to verify the derived analytical results. From the analytical results and simulations, it is concluded that a) with the increment of the channel parameter m, the secrecy performance of the considered networks increases in the low SNR region and decreases in the high SNR region, b) the connection performance with the outdated CSI of the interference links only reduce in the high SNR region, because the power margin factor changes significantly in this region, c) considering the impact of the constraint for the power, the secrecy performance and EST performance of the considered networks with the outdated CSI of the interference links increase in the high SNR region, d) the considered networks with NOMA scheme can achieve higher EST than that with orthogonal multiple access (OMA) scheme. INDEX TERMS Physical layer security, cognitive radio, non-orthogonal multiple access (NOMA), outdated channel state information, effective secrecy throughput.

Cancel‐Decode‐Encode Processing on Two‐Way Cooperative NOMA Schemes in Realistic Conditions

“…In [29], the joint effects of in-phase and quadrature-phase imbalance and ipSIC on the performance of TWR CNOMA networks over the Rician fading channels were studied. Besides, the realistic assumptions of the residual hardware impairments or ipCSIs of two-way or multiway CNOMA networks have also been considered in the articles [21,22,30]. Moreover, DNC and NOMA techniques can be combined to decreasing transmission time between devices and improve the performance system [5,31,32].…”

“…We also assume that the flat and block Rayleigh fading channels with the fading coefficients for links S k ⟶ R i and R i ⟶ S k are denoted as h S k R i and h R i S k , respectively, where k ∈ f1, 2g. In addition, perfect knowledge of all links is assumed at the receivers by channel estimators that are error-free [35], and the ipCSIs are only caused by the feedback delay with a time-variant channel representation and is described by [12,14,16,20,22,32,35]…”

“…The partial relay selection does not offer the full spatial diversity, but it is not as complicated as the full relay selection, and it is useful for applications in industrial IoT and wireless sensor networks. In most practical applications, CSIs cannot be perfectly measured and there are some mismatch, known as imperfect CSIs (ipCSIs) [12,14,16,[19][20][21][22]. The mismatch can happen due to the feedback delays of the CSIs [12,14,16,19,22] or the faults in the CSI estimating process [20,21].…”

“…In most practical applications, CSIs cannot be perfectly measured and there are some mismatch, known as imperfect CSIs (ipCSIs) [12,14,16,[19][20][21][22]. The mismatch can happen due to the feedback delays of the CSIs [12,14,16,19,22] or the faults in the CSI estimating process [20,21]. One-way NOMA and cooperative NOMA (CNOMA) networks with the SIC have been widely discussed to increase spectral efficiency gain, improve secure performance, enlarge system energy efficiency, and enhance significantly sum throughput in several studies [1,4,[23][24][25].…”

Matching Theory Based Physical Layer Secure Transmission Strategy for Cognitive Radio Networks

“…Information security is a critically important issue in cognitive radio networks (CRNs). Physical layer security, which exploits the intrinsic randomness of wireless channel to enhance the security, is developed, and user cooperation technology is widely recognized as one of the essentials for physical layer security [2]- [6].…”