Performance Analysis of Cognitive Two-Way Networks with Interference from Primary User over Nakagami-m Fading Channels

Author(s):  
Hoang Van Toan ◽  
Vo Nguyen Quoc Bao

A cognitive underlay two-way relay network taking into account interference links from primary transmitter to secondary receivers over Nakagami-m fading channels is analyzed in this article. In this model, a secondary system including two terminal nodes exchanges data through a decode-and-forward (DF) relay node. Under the underlay approach, all secondary transmitter must adjust transmit power to protect the primary communications. We derive the exact and asymptotic closed-form expression for the secondary system outage probability over Nakagami-m fading channels showing the system diversity. Monte-Carlo simulation are performed to verify the analysis results as well as to show the system characteristics

2021 ◽  
Vol 9 ◽  
Author(s):  
Jiaoli Liu ◽  
Jinyuan Wang ◽  
Bingyuan Zhang ◽  
Qinglin Wang

In this article, the secrecy performance of a hybrid radio frequency (RF)/visible light communication (VLC) system is studied. In this hybrid system, the source node (i.e., Alice) transmits information to the relay node via the outdoor RF link. Nakagami-m fading and path loss are considered for the RF link. The relay node includes an outdoor component and an indoor component, which are connected by using a wired medium. The outdoor component receives and recovers information by using the decode-and-forward (DF) relaying scheme and then transmits it to the indoor component. The indoor component then converts the received electrical signal into an optical signal by using a light-emitting diode. A legitimate receiver (i.e., Bob) deployed on the floor receives the optical signal. An eavesdropper (i.e., Eve) deployed in the RF or VLC link wiretaps the confidential information. In this study, we use the secrecy outage probability (SOP) and the probability of strictly positive secrecy capacity (SPSC) to evaluate the system performance. We then obtain the closed-form expression for a lower bound on the SOP and an exact closed-form expression for the probability of SPSC when the RF and VLC links are wiretapped, respectively. Numerical results are presented to validate the accuracy of our derivations. We further discuss the effects of the noise standard deviation, the equivalent threshold of the signal-to-noise ratio, and the floor radius on the system secrecy performance when the VLC link is eavesdropped upon. For the case when the RF link is eavesdropped upon, the impacts of the distance between Alice and the relay, the path loss exponent, the fading factor, and the distance between Alice and Eve on secrecy performance are also provided.


Author(s):  
Vo Nguyen Quoc Bao ◽  
Vu Van San

In this paper, we propose a novel derivation approach to obtain the exact closed form expression of ergodic capacity for cognitive underlay amplify-and-forward (AF) relay networks over Rayleigh fading channels. Simulation results are performed to verify the analysis results. Numerical results are provided to compare the system performance of cognitive underlay amplify-and-forward relay networks under both cases of AF and decode-and-forward (DF) confirming that the system with DF provides better performance as compared with that with AF. DOI: 10.32913/rd-ict.vol3.no14.563


Author(s):  
Dinh-Thuan Do

In this paper, we consider one-way  relay with energy harvesting system based on power beacon (PB), in which the relay node harvests transmitted power from the PB station to forward signals to destination. We also analyse the relay network model with amplify-and-forward (AF) protocol for information cooperation and Power Splitting-based Relaying (PSR) protocol for power transfer. In particular, the outage probability and optimal energy harvesting (EH) power splitting fraction of novel scheme in are presented. We obtain analytical closed-form expression of  optimal energy harvesting (EH) power splitting fraction to minimize the outage probability of system. Using numerical and analytical simulations, the performances of different cases are presented and discussed.


Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 3946 ◽  
Author(s):  
Chunling Peng ◽  
Fangwei Li ◽  
Huaping Liu ◽  
Guozhong Wang

A joint resource allocation algorithm to minimize the system outage probability is proposed for a decode-and-forward (DF) two-way relay network with simultaneous wireless information and power transfer (SWIPT) under a total power constraint. In this network, the two sources nodes exchange information with the help of a passive relay, which is assumed to help the two source nodes’ communication without consuming its own energy by exploiting an energy-harvesting protocol, the power splitting (PS) protocol. An optimization framework to jointly optimize power allocation (PA) at the source nodes and PS at the relay is developed. Since the formulated joint optimization problem is non-convex, the solution is developed in two steps. First, the conditionally optimal PS ratio at the relay node for a given PA ratio is explored; then, the closed-form of the optimal PA in the sense of minimizing the system outage probability with instantaneous channel state information (CSI) is derived. Analysis shows that the optimal design depends on the channel condition and the rate threshold. Simulation results are obtained to validate the analytical results. Comparison with three existing schemes shows that the proposed optimized scheme has the minimum system outage probability.


2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
Zongsheng Zhang ◽  
Jinlong Wang ◽  
Qihui Wu ◽  
Xurong Pi

The outage performance with best relay selection is proposed for cognitive relay networks with multiple primary users in independent nonidentical distributed Nakagami-m fading channels. Specifically, we take the interference temperature and fading severity into consideration. Exact closed-form expression of outage probability is derived. Based on the exact closed-form expression, we can evaluate the impact of interference temperature, fading severity, number of relays, and number of primary users on the secondary network. Finally, the effects of fading severity, number of relays, number of primary users, and interference temperature on the system performance are examined through some representative numerical plots, and the Monte Carlo results match perfectly with theory results which validates our theory analysis.


1987 ◽  
Vol 54 (3) ◽  
pp. 688-694 ◽  
Author(s):  
W. D. Iwan ◽  
K. S. Smith

The envelope response of a secondary system is derived for the case where the primary system is subjected to nonstationary stochastic excitation. An approximate closed form expression for the mean square envelope response is obtained for the case of transient response to stationary excitation when the primary and secondary systems are noninteracting. When the combined system is classically damped, the effect of the interaction is described by the introduction of an equivalent noninteracting system. The analytical results are compared with results of numerical simulations.


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