scholarly journals On the coexistence of a primary user with an energy harvesting secondary user: a case of cognitive cooperation

2014 ◽  
Vol 16 (2) ◽  
pp. 166-176 ◽  
Author(s):  
Ahmed El Shafie ◽  
Tamer Khattab ◽  
Amr El-Keyi ◽  
Mohamed Nafie
Keyword(s):  
Energy Harvesting ◽  
Primary User ◽  
Secondary User

scholarly journals Secrecy Energy Efficiency Maximization in an Underlying Cognitive Radio–NOMA System with a Cooperative Relay and an Energy-Harvesting User

2020 ◽  
Vol 10 (10) ◽  
pp. 3630 ◽  
Author(s):  
Carla E. Garcia ◽  
Mario R. Camana ◽  
Insoo Koo
Keyword(s):  
Energy Efficiency ◽  
Cognitive Radio ◽  
Energy Harvesting ◽  
Multiple Access ◽  
Pso Algorithm ◽  
Critical Issue ◽  
Primary User ◽  
Secondary User ◽  
Cooperative Relay ◽  
Security Issue

Security is considered a critical issue in the deployment of 5G networks because of the vulnerability of information that can be intercepted by eavesdroppers in wireless transmission environments. Thus, physical layer security has emerged as an alternative for the secure enabling of 5G technologies and for tackling this security issue. In this paper, we study the secrecy energy efficiency (SEE) in a downlink underlying cognitive radio (CR)—non-orthogonal multiple access (NOMA) system with a cooperative relay. The system has an energy-harvesting (EH) user and an eavesdropper, where the transmitter provides direct communication with a close secondary user and a distant secondary user via the relay. Our objective is to maximize the SEE of the CR-NOMA system under the constraints of a minimum information rate for the secondary users, a minimum amount of energy harvested by the EH user, and maximum power availability at the transmitter and the relay that still prevents them from causing unacceptable interference with the primary user. The proposed solution to maximize the SEE is based on the low-computational—complexity particle swarm optimization (PSO) algorithm. For validation purposes, we compare the optimization outcomes obtained by the PSO algorithm with the optimal exhaustive search method. Furthermore, we compare the performance of our proposed CR-NOMA scheme with the conventional orthogonal multiple access (OMA) scheme.

scholarly journals On the Retrial-Queuing Model for Strategic Access and Equilibrium-Joining Strategies of Cognitive Users in Cognitive-Radio Networks with Energy Harvesting

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2088
Author(s):  
Kalpana Devarajan ◽  
Muthukrishnan Senthilkumar
Keyword(s):  
Cognitive Radio ◽  
Energy Harvesting ◽  
Performance Metrics ◽  
Stackelberg Game ◽  
Retrial Queue ◽  
Primary User ◽  
Secondary User ◽  
Single Server ◽  
Queuing Model ◽  
Secondary Users

This article studies the strategic access of single-server retrial queue with two types of customers, where priority is given according to their category. On the basis of this concept, a cognitive-radio network was developed as retrial queue with energy harvesting. Cognitive radio allows for a secondary user to opportunistically access the idle spectrum of a primary user (PU). Upon arrival of a primary user, the service given to the secondary user by the cognitive radio is interrupted, and the PU band is available for the primary user. After completion of service for the primary user, the PU band is again available to secondary users. Performance metrics are derived to study the equilibrium strategies of secondary users. A Stackelberg game was formulated and Nash equilibrium was derived for the noncooperative strategy of the secondary user. Game-theory concepts are incorporated with queuing theory ideas to obtain the net benefit for the noncooperative strategy and social benefit for cooperative strategy. Lastly, analytical results are verified with numerical examples, and the effects of energy-harvesting rate are discussed.

Energy Harvesting in Cognitive Networks Using Feasible Channel Selection Assignment

2020 ◽  
Vol 13 (2) ◽  
pp. 173-182
Author(s):  
M. Balasubramanian ◽  
V. Rajamani
Keyword(s):  
Cognitive Radio ◽  
Energy Harvesting ◽  
Primary User ◽  
Spectrum Management ◽  
Cognitive Networks ◽  
Secondary User ◽  
Spectrum Efficiency ◽  
Cognitive Radio Systems ◽  
Token Passing ◽  
Radio Systems

Background: The importance of this paper is to achieve maximum spectrum efficiency and proper channel allotment between Primary and Secondary User. The licensed and unlicensed users gets promoted as the channel allotment is properly carried out. To improve energy capability and spectral proficiency consider energy collecting cognitive radio systems to update both energy feasibility and spectral viability. Energy Harvesting Provides possibility of sharing energy in wireless networks which improves the performance of channel capacity. Methods: In this paper an Token Passing algorithm is proposed that switches the channels between Primary User and Secondary User. The energy efficiency decision is taken according to when primary user is idle or not. When the primary user is idle the secondary user cannot harvest any energy and when the primary channel is occupied the secondary channel harvest energy from primary user so that the harvested energy will be used by the secondary user during channel allotment. This proposed algorithm provides energy harvesting and spectrum efficiency. Results: The result shows that the most extraordinary achievable throughput R (eh) of the energy harvesting cognitive radio. The State Transition will move from busy to idle and idle to busy which is represented as S0 and S1. The other parameters are Sensing Energy es, Sampling frequency fs, Primary Signal which accepts a noise SNR γp. As Token Passing Algorithm provides tokens for primary and secondary user it takes lesser time and achieves better throughput than the FDMA and suboptimal algorithm. Conclusion: This paper achieves the maximum spectrum efficiency and energy harvesting by properly allotting spectrum for both primary and secondary user. The primary user and secondary user and spectrum management perform the channel allotment efficiently through the idle and busy state and Token Passing Algorithm does energy harvesting. An efficient scheme is developed for allocating energy in energy harvesting cognitive radio systems.

scholarly journals Optimal Time Assignment Policy for Maximizing Throughput in Cognitive Sensor Network with Energy Harvesting

Sensors ◽  
2018 ◽  
Vol 18 (8) ◽  
pp. 2540 ◽  
Author(s):  
Hao Wu ◽  
Yong Chen
Keyword(s):  
Energy Harvesting ◽  
Sensor Network ◽  
Optimization Problem ◽  
Primary User ◽  
Spectrum Efficiency ◽  
Optimal Time ◽  
Lower And Upper Bounds ◽  
Uniqueness And Existence ◽  
Energy Harvesting Devices ◽  
Idle Channel

A cognitive sensor network with energy harvesting (EH-CSN) is a promising paradigm to address the issues both in spectrum efficiency and in energy efficiency. The cognitive sensors (CSs) equipped with energy harvesting devices are assumed to operate in a harvesting-sensing-transmission mode and permitted to access the idle licensed frequency bands without causing any harmful jamming to the primary user. By identifying the time fractions of harvesting, sensing, and transmission, we can discuss some design considerations for the EH-CSN. In the meantime, considering the possibility that the primary user may reoccupy the idle channel during the CS’s data transmission duration, we formulate an optimization problem to maximize the average throughput of EH-CSN under a collision constraint and an energy constraint. After deriving the lower and upper bounds of the time fraction for energy harvesting, the uniqueness and existence of the optimal time fraction set have been proved. Finally, our theoretical analysis is also verified through numerical simulations.

scholarly journals ANALISIS PENDEKATAN GAME THEORY UNTUK PEMILIHAN KANAL PADA JARINGAN RADIO KOGNITIF

Transmisi ◽  
2018 ◽  
Vol 20 (2) ◽  
pp. 57
Author(s):  
Norma Amalia
Keyword(s):  
Game Theory ◽  
Primary User ◽  
Secondary User

Spektrum frekuensi pada jaringan komunikasi nirkabel bersifat terbatas. Oleh karena itu diperlukan solusi dalam mengoptimalkan penggunaan spektrum frekuensi, salah satunya adalah dengan penggunaan jaringan radio kognitif. Spektrum pada jaringan radio kognitif bersifat heterogen, yaitu terdiri dari Primary User (PU) dan Secondary User (SU). Pada jaringan radio kognitif, SU dapat menggunakan kanal yang sama dengan PU selama SU tidak menyebabkan interferensi yang dapat menurunkan unjuk kerja dari PU. Salah satu metode yang dapat digunakan untuk meminimalkan interferensi adalah dengan metode pemilihan kanal menggunakan pendekatan game theory. Dengan metode ini, interferensi SU terhadap PU dapat diminimalkan. Pada penelitian ini, dianalisis kinerja dari metode pemilihan kanal menggunakan pendekatan game theory. Unjuk kerja jaringan radio kogntif dapat ditingkatkan dengan dengan menggunakan pemilihan kanal dengan pendekatan game theory. Pada jaringan radio kognitif tanpa keberadaan PU, nilai throughput tanpa pendekatan game theory PU sebesar 20,28 bps sedangkan dengan pendekatan game theory sebesar 23,58 bps. Nilai rata-rata SIR tanpa pendekatan game theory sebesar 18,08 dB sedangkan dengan pendekatan game theory sebesar 21,4 dB.

scholarly journals Multichannel spectrum sensing over correlated fading channels with diversity reception

2021 ◽  
Author(s):  
Salam Al-Juboori ◽  
Xavier Fernando
Keyword(s):  
Closed Form ◽  
Fading Channels ◽  
Spectrum Sensing ◽  
Detection Probability ◽  
Multipath Fading ◽  
Primary User ◽  
Secondary User ◽  
Selection Combining ◽  
Standard Normal Distribution ◽  
Correlated Fading

Accurate detection of white spaces is crucial to protect primary user against interference with secondary user. Multipath fading and correlation among diversity branches represent essential challenges in Cognitive Radio Network Spectrum Sensing (CRNSS). This dissertation investigates the problem of correlation among multiple diversity receivers in wireless communications in the presence of multipath fading. The work of this dissertation falls into two folds, analysis and solution. In the analysis fold, this dissertation implements a unified approach of performance analysis for cognitive spectrum sensing. It considers a more realistic sensing scenario where non-independent multipath fading channels with diversity combining technique are assumed. Maximum Ratio Combining (MRC), Equal Gain Combining (EGC), Selection Combining (SC) and Selection and Stay Combining (SSC) techniques are employed. Arbitrarily, constant and exponentially dual, triple and L number of Nakagami-m correlated fading branches are investigated. We derive novel closed-form expressions for the average detection probability for each sensing scenario with simpler and more general alternative expressions. Our numerical analysis reveals the deterioration in detection probability due to correlation especially in deep fading. Consequently, an increase in the interference rate between the primary user and secondary user is observed by three times its rate when independent fading branches is assumed. However, results also show that this effect could be compensated for, through employing the appropriate diversity technique and by increasing the diversity branches. Therefore, we say that the correlation cannot be overlooked in deep fading, however in low fading can be ignored so as to reduce complexity and computation. Furthermore, at low fading, low false alarm probability and highly correlated environments, EGC which is simpler scheme performs as good as MRC which is a more complex scheme. Similar result are observed for SC and SSC. For the solution fold and towards combatting the correlation impact on the wireless systems, a decorrelator implementation at the receiver will be very beneficial. We propose such decorrelator scheme which would significantly alleviate the correlation effect. We derive closed-form expressions for the decorrelator receiver detection statistics including the Probability Density Function (PDF) from fundamental principles, considering dual antenna SC receiver in Nakagami-m fading channels. Numerical results show that the PDF of the bivariate difference could be perfectly represented by a semi-standard normal distribution with zero mean and constant variance depending on the bivariate's parameters. This observation would significantly help simplifying the design of decorrelator receiver. The derived statistics can be used in the problem of self-interference for multicarrier systems. Results also show the outage probability has been improved by double, due to the decorrelator.

scholarly journals Resource Allocation with Successive Coding for OFDM-Based Cognitive System Subject to Statistical CSI

2018 ◽  
Vol 2018 ◽  
pp. 1-15
Author(s):  
Marwa Chami ◽  
Mylene Pischella ◽  
Didier Le Ruyet
Keyword(s):  
Resource Allocation ◽  
Interference Cancellation ◽  
Primary User ◽  
Secondary User ◽  
Sequential Algorithm ◽  
Total Power ◽  
Superposition Coding ◽  
Channel State ◽  
Radio System ◽  
Underlay Cognitive Radio

This paper investigates the resource allocation problem for a multicarrier underlay cognitive radio system, under the assumption that only statistical Channel State Information (CSI) about the primary channels is available at the secondary user. More specifically, we maximize the system utility under primary and secondary user outage constraints and the total power constraint. The secondary user transmission is also constrained by the interference threshold imposed by the primary user. Moreover, the secondary receiver adapts its decoding strategy, which is either treating interference as noise or using successive interference cancellation or superposition coding. This leads to a nonconvex optimization problem, with either perfect or statistical CSI. Consequently, we propose a sequential-based algorithm to efficiently obtain a solution to the problem. The simulation results show that the sequential algorithm is convergent and that our global proposed scheme achieves larger secondary and sum rates than other algorithms where the decoding strategy is not adapted.

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