scholarly journals On The Performance of Underlay Relay Cognitive Networks

2013 ◽  
Vol 3 (1-2) ◽  
Author(s):  
Khuong Ho-Van ◽  
Vo Nguyen Quoc Bao
Keyword(s):  
Rayleigh Fading ◽  
Network Performance ◽  
Cognitive Networks ◽  
Interference Power ◽  
Power Constraint ◽  
Linear Network ◽  
Transmit Power ◽  
System Parameters ◽  
Analytic Expressions ◽  
Maximum Transmit Power

The bit error rate (BER) performance of underlay relay cognitive networks in the presence of Rayleigh fading is thoroughly analyzed in this paper. New exact and asymptotic analytic expressions under consideration of both interference power constraint and maximum transmit power constraint are derived in closed-form and are extensively corroborated by Monte-Carlo simulations. These expressions facilitate in evaluating effectively the network performance behaviour in key operation parameters as well as in optimizing system parameters. A multitude of analytical results expose that underlay relay cognitive networks experience the performance saturation phenomena while their performance considerably depends on the number of hops for the linear network model. Additionally, optimum relay position is significantly dependent of maximum transmit power, maximum interference power, and licensee location. Moreover, the appropriate order of locating unlicensees with different maximum transmit power levels can dramatically improve the network performance.

scholarly journals Security Analysis for Underlay Cognitive Network with Energy-Scavenging Capable Relay over Nakagami-m Fading Channels

2019 ◽  
Vol 2019 ◽  
pp. 1-16 ◽  
Author(s):  
Khuong Ho-Van ◽  
Thiem Do-Dac
Keyword(s):  
Fading Channels ◽  
Security Analysis ◽  
Cognitive Networks ◽  
Energy Scavenging ◽  
Secrecy Outage Probability ◽  
Interference Power ◽  
Transmit Power ◽  
High Maximum ◽  
Maximum Transmit Power ◽  
Secrecy Outage

This study suggests an energy-scavenging capable unlicensed relay not only to retain communications between an unlicensed sender-recipient pair in underlay cognitive networks but also to secure these communications against eavesdropping of malicious users. Message-securing capability of such a network configuration is assessed through secrecy outage probability (SOP). For this purpose, a precise closed-form formula of the SOP accounting for interference power restriction, Nakagami-m fading, and maximum transmit power restriction is first proposed. Then, the proposed formula is validated by computer simulations. Ultimately, various results are supplied to contrive that the relay position, the time percentage, and the power percentage of the energy-scavenging technique should be appropriately chosen for achieving the best security performance. Moreover, the SOP decreases with lower severity fading level and is constant in the range of high maximum interference power or high maximum transmit power.

scholarly journals Maximum Transmit Power for UE in an LTE Small Cell Uplink

Electronics ◽  
2019 ◽  
Vol 8 (7) ◽  
pp. 796 ◽  
Author(s):  
Amir Haider ◽  
Seung-Hoon Hwang
Keyword(s):  
Power Control ◽  
Network Performance ◽  
Fractional Power ◽  
Small Cell ◽  
Control Mode ◽  
Small Cells ◽  
Transmit Power ◽  
Lte Networks ◽  
Maximum Transmit Power ◽  
The Impact

To furnish the network with small cells, it is vital to consider parameters like cell size, interference in the network, and deployment strategies to maximize the network’s performance gains expected from small cells. With a small cell network, it is critical to analyze the impact of the uplink power control parameters on the network’s performance. In particular, the maximum transmit power (Pmax) for user equipment (UE) needs to be revisited for small cells, since it is a major contributor towards interference. In this work, the network performance was evaluated for different Pmax values for the small cell uplink. Various deployment scenarios for furnishing the existing macro layer in LTE networks with small cells were considered. The Pmax limit for a small cell uplink was evaluated for both homogenous small cell and heterogeneous networks (HetNet). The numerical results showed that it would be appropriate to adopt Pmax = 18 dBm in uniformly distributed small cells rather than Pmax = 23 dBm, as in macro environments. The choice of Pmax = 18 dBm was further validated for three HetNet deployment scenarios. A decrease of 0.52 dBm and an increase of 0.03 dBm and 3.29 dBm in the proposed Pmax = 18 dBm were observed for the three HetNet deployments, respectively. Furthermore, we propose that the fractional power control mode can be employed instead of the full compensation mode in small cell uplinks.

scholarly journals Reliability-Security Trade-Off Analysis of Cognitive Radio Networks with Jamming and Licensed Interference

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Khuong Ho-Van ◽  
Thiem Do-Dac
Keyword(s):  
Cognitive Radio ◽  
Cognitive Radio Networks ◽  
Rayleigh Fading ◽  
Feasible Solution ◽  
Radio Networks ◽  
Power Constraint ◽  
Trade Off ◽  
Maximum Transmit Power ◽  
The Difference ◽  
Non Gaussian

Cognitive radio networks (CRNs) allow coexistence of unlicensed users (UUs) and licensed users (LUs) and hence, mutual interference between UUs and LUs is neither ignored nor considered as Gaussian-distributed quantity. Additionally, exploiting jamming signals to purposely interfere with signal reception of eavesdroppers is a feasible solution to improve security performance of CRNs. This paper analyzes reliability-security trade-off, which accounts for maximum transmit power constraint, interference power constraint, jamming signal, and Rayleigh fading, and considers interference from LUs as non-Gaussian-distributed quantity. Toward this end, exact closed-form expressions of successful detection probability and successful eavesdropping probability, from which reliability-security trade-off is straightforwardly visible, are first suggested and then validated by Monte-Carlo simulations. Various results demonstrate that interference from LUs considerably decreases both probabilities while jamming signal enlarges the difference between them, emphasizing its effectiveness in improving security performance.

scholarly journals Relaying Communications in Energy Scavenging Cognitive Networks: Secrecy Outage Probability Analysis

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Khuong Ho-Van ◽  
Thiem Do-Dac
Keyword(s):  
Outage Probability ◽  
Cognitive Networks ◽  
Closed Form Expression ◽  
Energy Scavenging ◽  
Secondary Source ◽  
Secrecy Outage Probability ◽  
Transmit Power ◽  
Splitting Factor ◽  
Maximum Transmit Power ◽  
Secrecy Outage

This paper exploits a self-powered secondary relay to not only maintain but also secure communications between a secondary source and a secondary destination in cognitive radio networks when source-destination channel is unavailable. The relay scavenges energy from radio frequency (RF) signals of the primary transmitter and the secondary source and consumes the scavenged energy for its relaying activity. Under the maximum transmit power constraint, Rayleigh fading, the primary outage constraint, and the interference from the primary transmitter, this paper suggests an accurate closed-form expression of the secrecy outage probability to promptly assess the security performance of relaying communications in energy scavenging cognitive networks. The validity of the proposed expression is verified by computer simulations. Numerous results demonstrate the security performance saturation in the range of large maximum transmit power or high required outage probability of primary users. Moreover, the security performance is a function of several system parameters among which the relay’s position, the power splitting factor, and the time splitting factor can be optimized to achieve the minimum secrecy outage probability.

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