scholarly journals Intelligent Reflecting Surface-Assisted Secure Multi-Input Single-Output Cognitive Radio Transmission

Sensors ◽  
2020 ◽  
Vol 20 (12) ◽  
pp. 3480 ◽  
Author(s):  
Haitao Xiao ◽  
Limeng Dong ◽  
Wenjie Wang
Keyword(s):  
Cognitive Radio ◽  
Closed Form Solution ◽  
Initial Point ◽  
Green Energy ◽  
Total Power ◽  
Power Constraint ◽  
Secrecy Rate ◽  
Single Output ◽  
Bisection Search ◽  
Reflecting Surface

Intelligent reflecting surface (IRS) is a very promising technology for the development of beyond 5G or 6G wireless communications due to its low complexity, intelligence, and green energy-efficient properties. In this paper, we combined IRS with physical layer security (PLS) to solve the security issue of cognitive radio (CR) networks. Specifically, an IRS-assisted multi-input single-output (MISO) CR wiretap channel was studied. To maximize the secrecy rate of secondary users subject to a total power constraint (TPC) for the transmitter and interference power constraint (IPC) for a single antenna primary receiver (PR) in this channel, an alternating optimization (AO) algorithm is proposed to jointly optimize the transmit covariance R at transmitter and phase shift coefficient Q at IRS by fixing the other as constant. When Q is fixed, R is globally optimized by equivalently transforming the quasi-convex sub-problem to convex one. When R is fixed, bisection search in combination with minorization–maximization (MM) algorithm was applied to optimize Q from the non-convex fractional programming sub-problem. During each iteration of MM, another bisection search algorithm is proposed, which is able to find the global optimal closed-form solution of Q given the initial point from the previous iteration of MM. The convergence of the proposed algorithm is analyzed, and an extension of applying this algorithm to multi-antenna PR case is discussed. Simulations have shown that our proposed IRS-assisted design greatly enhances the secondary user’s secrecy rate compared to existing methods without IRS. Even when IPC is active, the secrecy rate returned by our algorithm increases with transmit power as if there is no IPC at all.

scholarly journals Energy Efficiency Design for Secure MISO Cognitive Radio Network Based on a Nonlinear EH Model

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Lei Ni ◽  
Xinyu Da ◽  
Hang Hu ◽  
Miao Zhang
Keyword(s):  
Energy Efficiency ◽  
Cognitive Radio ◽  
Optimization Problem ◽  
Optimal Solution ◽  
Primary User ◽  
Open Architecture ◽  
Maximization Problem ◽  
Transmit Beamforming ◽  
Secrecy Rate ◽  
Single Output

In this work, we investigate the secrecy energy efficiency (SEE) optimization problem for a multiple-input single-output (MISO) cognitive radio (CR) network based on a practical nonlinear energy-harvesting (EH) model. In particular, the energy receiver (ER) is assumed to be a potential eavesdropper due to the open architecture of a CR network with simultaneous wireless information and power transfer (SWIPT), such that the confidential message is prone to be intercepted in wireless communications. The aim of this work is to provide a secure transmit beamforming design while satisfying the minimum secrecy rate target, the minimum EH requirement, and the maximum interference leakage power to primary user (PU). In addition, we consider that all the channel state information (CSI) is perfectly known at the secondary transmitter (ST). We formulate this beamforming design as a SEE maximization problem; however, the original optimization problem is not convex due to the nonlinear fractional objective function. To solve it, a novel iterative algorithm is proposed to obtain the globally optimal solution of the primal problem by using the nonlinear fractional programming and sequential programming. Finally, numerical simulation results are presented to validate the performance of the proposed scheme.

scholarly journals Opportunistic Communication (Cognitive Radio) over Primary Discarded Subchannels by Applying a Double Power Distribution

2010 ◽  
Vol 2010 ◽  
pp. 1-9
Author(s):  
G. A. Medina-Acosta ◽  
José A. Delgado-Penín
Keyword(s):  
Cognitive Radio ◽  
Power Distribution ◽  
Primary User ◽  
Total Power ◽  
Radio Communication ◽  
Power Constraint ◽  
Transmission Scheme ◽  
Opportunistic Communication ◽  
Optimal Power ◽  
Channel Realization

This paper proposes the establishment of a simultaneous cognitive radio communication based on a subdistribution of power made over unselected subchannels which were discarded by the primary user through an initial optimal power allotment. The aim of this work is to show the possibility of introducing an opportunistic communication into a licensed transmission where the total power constraint is shared. The analysis of the proposed transmission scheme was performed by considering 128 and 2048 independent subchannels affected byRayleighfading, over 10,000 channel realizations, and three different signal-to-noise ratios (8 , 16 , and 24 ). From the system evaluation it was possible to find the optimal power allotment for the primary user, the subdistribution of power for the secondary user, as well as the attenuation and the capacity per subchannel for every channel realization. Moreover, thePDFandCDFof the total obtained capacities, as well as the generation of empirical capacity regions, were estimated as complementary results.

Power Allocation and Relay Selection Algorithm in Multi-Relay Amplify-and-Forward Networks

2014 ◽  
Vol 513-517 ◽  
pp. 3423-3428
Author(s):  
Zhi Kang Zhou ◽  
Qi Zhu
Keyword(s):  
Power Allocation ◽  
Relay Selection ◽  
Relay Network ◽  
Total Power ◽  
Selection Algorithm ◽  
Amplify And Forward ◽  
Power Constraint ◽  
Lower Complexity ◽  
Relay Selection Algorithm ◽  
The Ideal

In this paper, an amplify-and-forward (AF) multi-relay network is considered. In order to minimize the system outage probability, a new power allocation and multi-relay selection algorithm is proposed under total power constraint and each node power constraint. In the proposed algorithm, the ideal of ordering is adopted, which leads to the remarkable decrease of the computation complexity together with simple power reallocation. Simulation results show that the proposed multi-relay selection algorithm performs close to the optimal scheme with optimal power allocation and exhaustive search (OPA-ES) but with much lower complexity.

Robust secrecy rate optimisations for multiuser multiple-input-single-output channel with device-to-device communications

2015 ◽  
Vol 9 (3) ◽  
pp. 396-403 ◽  
Author(s):  
Zheng Chu ◽  
Kanapathippillai Cumanan ◽  
Zhiguo Ding ◽  
Mai Xu
Keyword(s):  
Output Channel ◽  
Secrecy Rate ◽  
Single Output ◽  
Multiple Input ◽  
Device To Device

scholarly journals A Novel Pilot Spoofing Scheme via Intelligent Reflecting Surface Based On Statistical CSI

2020 ◽  
Author(s):  
jie yang ◽  
Xinsheng Ji ◽  
Kaizhi Huang ◽  
Xiaoli Sun ◽  
Xiaoming Xu
Keyword(s):  
Original Problem ◽  
Optimal Solution ◽  
Phase Shifts ◽  
Communication Process ◽  
Secrecy Rate ◽  
Channel State ◽  
Wireless Environment ◽  
Time Division ◽  
Reflecting Surface ◽  
Secure Transmission

Pilot spoofing attack brings challenges to the physical layer secure transmission. However, since the inherent characteristics of wireless environment have not changed, active eavesdropping can be detected based on prior information. Intelligent reflecting surface (IRS), with the real-time programmable characteristics for wireless environment, provides new possibilities for effective pilot spoofing. In this paper, the IRS is deployed near the legitimate users and the control strategy is embeded into the legitimate communication process under time-division duplex (TDD) mode to assist eavesdroppers to implement pilot spoofing. By designing different phase shifts at the IRS during the uplink phase and downlink phase, the channel reciprocity between uplink and downlink disappears, and thus the secure beamforming vector is biased towards the eavesdropper. Furthermore, in order to obtain more information, the average secrecy rate based on the statistical channel state information is established by carefully designing the phase shifts. The formulated problem is non-trivial to solve. By using alternating optimization and Charnes-Cooper transformation technique, the original problem is transformed into convex form and a sub-optimal solution is achieved. Finally, simulation results show that our proposed scheme poses serious secure threat for TDD systems.

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

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Quanzhong Li ◽  
Sai Zhao
Keyword(s):  
Cognitive Radio ◽  
Secure Communication ◽  
Multiple Access ◽  
Spectrum Efficiency ◽  
Maximization Problem ◽  
Artificial Noise ◽  
Practical Case ◽  
Secrecy Rate ◽  
Worst Case ◽  
Rank One

By the integration of cooperative cognitive radio (CR) and nonorthogonal multiple access (NOMA), cooperative CR NOMA networks can improve the spectrum efficiency of wireless networks significantly. Due to the openness and exposure of wireless signals, secure communication is an important issue for cooperative CR NOMA networks. In this paper, we investigate the physical layer security design for cooperative CR NOMA networks. Our objective is to achieve maximum secrecy rate of the secondary user by designing optimal beamformers and artificial noise covariance matrix at the multiantenna secondary transmitter under the quality-of-service at the primary user and the transmit power constraint at the secondary transmitter. We consider the practical case that the channel state information (CSI) of the eavesdropper is imperfect, and we model the imperfect CSI by the worst-case model. We show that the robust secrecy rate maximization problem can be transformed to a series of semidefinite programmings based on S-procedure and rank-one relaxation. We also propose an effective method to recover the optimal rank-one solution. Simulations are provided to show the effectiveness of our proposed robust secure algorithm with comparison to the nonrobust secure design and traditional orthogonal multiple access schemes.

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