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1
Content available Multi-objective Channel Decision for Adhoc Cognitive Radio Network
Awathankar Rahul V, Rukmini M S S, Raut Rajeshree D
International Journal of Electronics and Telecommunications
|
2019
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Vol. 65, No. 2
253--257
EN
Faithfull detection of non-utilized spectrum hole in available channel is a crucial issue for cognitive radio network. Choosing the best available channel for a secondary user transmission includes settling on decision of accessible choices of free frequency spectrum based on multiple objectives. Thus channel judgment can be demonstrated as several objective decision making (MODM) problem. An ultimate goal of this exploration is to define and execute a technique for multiple objective optimizations of multiple alternative of channel decision in Adhoc cognitive radio network. After a coarse review of an articles related to the multiple objective decision making within a process of channel selection, Multiple Objective Optimization on the basis of the Ratio Analysis (MOORA) technique is taken into consideration. Some important objectives values of non-utilized spectrum collected by a fusion center are proposed as objectives for consideration in the decision of alternatives. MOORA method is applied to a matrix f replies of each channel alternatives to channel objectives which results in set ratios. Among the set of obtained dimensionless ratios, all the channel alternatives are ranked in descending order. In MOORA, channel choices with moderate objectives can top in ranking order, which is hardly conceivable with linearly weighted objectives of the different channel by using different decision making technique.
2
Analysis of energy harvesting in cognitive femtocell radio network
Martyna J.
Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne
|
2018
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nr 6
409--412, CD
EN
Harvesting energy is one of the method to mitigate energy deficiency, prolong device lifetime in cognitive femtocell network (CFN). Moreover, the energy harvesting can reduce the battery size of all secondary user (SU) devices used in CFNs. In the paper, an algorithm to maximise the average throughput of the secondary system over a time slot is presented. Additionally, increased throughput performance can improve the energy budget of SUs. The numerical simulation results prove the correctness of the analysis and the possibility of applying it in practical situations.
PL
Przechwytywanie energii emitowanej przez przekaźniki radiowe jest jedną z metod łagodzenia niedoboru energii i przedłużania żywotności urządzeń kognitywnej sieci femtokomórkowej (CFN). Tego rodzaju pozyskiwanie energii może też zmniejszyć rozmiar baterii wszystkich urządzeń nielicencjonowanych użytkowników (SUs) używanych w CFN. W artykule przedstawiono algorytm maksymalizujący przepustowość urządzeń SUs. Dodatkowo zwiększona przepustowość może poprawić budżet energetyczny tych urządzeń. Wyniki symulacji dowodzą poprawności analizy i możliwości jej zastosowania w sytuacjach praktycznych.
3
Content available Optimal Spectrum Sensor Assignment in Multi-channel Multi-user Cognitive Radio Networks
Nandini K. S., Hariprasad S. A.
Journal of Telecommunications and Information Technology
|
2018
|
nr 4
88--96
EN
Accurate detection of spectrum holes is the most important and critical task in any cognitive radio (CR) communication system. When a single spectrum sensor is assigned to detect a specific primary channel, then the detection may be unreliable because of noise, random multipath fading and shadowing. Also, even when the primary channel is invisible at the CR transmitter, it may be visible at the CR receiver (the hidden primary channel problem). With a single sensor per channel, a high and consistently uniform level of sensitivity is required for reliable detection. These problems are solved by deploying multiple heterogeneous sensors at distributed locations. The proposed spectrum hole detection method uses cooperative sensing, where the challenge is to properly assign sensors to different primary channels in order to achieve the best reliability, a minimum error rate and high efficiency. Existing methods use particle swarm optimization, the ant colony system, the binary firefly algorithm, genetic algorithms and non-linear mixed integer programming. These methods are complex and require substantial pre-processing. The aim of this paper is to provide a simpler solution by using simpler binary integer programming for optimal assignment. Optimal assignment minimizes the probability of interference which is a non-linear function of decision variables. We present an approach used to linearize the objective function. Since multiple spectrum sensors are used, the optimal constrained assignment minimizes the maximum of interferences. While performing the optimization, the proposed method also takes care of the topological layout concerned with channel accessibility. The proposed algorithm is easily scalable and flexible enough to adapt to different practical scenarios.
4
Content available On the Evaluation of Handover Exchange Schemes Between Two Cognitive Radio Base Stations with and without Buffers
Esenogho E., Mambou E. N., Ferreira H. C.
International Journal of Electronics and Telecommunications
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2018
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Vol. 64, No. 4
513--518
EN
This article investigates and evaluates a handover exchange scheme between two secondary users (SUs) moving in different directions across the handover region of neighboring cell in a cognitive radio network. More specifically, this investigation compares the performance of SUs in a cellular cognitive radio network with and without channel exchange scheme. The investigation shows reduced handover failure, blocking, forced and access probabilities respectively, for handover exchange scheme with buffer as compared to exchange scheme without buffer. It also shows transaction within two cognitive nodes within a network region. The system setup is evaluated through system simulation.
5
Optimal power allocation for cognitive LTE-femtocell networks based on game theory
Martyna J.
Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne
|
2017
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nr 8-9
1067--1071, CD
EN
In this paper, a new power control scheme for cognitive LTE-femtocell networks based on game theory is proposed. The problem is formulated as a coalition graph game problem to maximise throughput and system fairness. Then, a heuristic low-complexity algorithm to solving so presented problem is given. Simulation results have validated that the proposed scheme is effective in managing the cognitive femtocell network.
PL
W tym artykule proponuje się nowy schemat kontroli mocy dla sieci kognitywnych femtokomórek LTE oparty o teorię gier. Problem jest sformułowany jako gra koalicyjna, maksymalizująca przepustowość i sprawiedliwość systemu. Następnie, przedstawiono heurystyczny algorytm o małej złożoności dla rozwiązanie tego problemu. Wyniki symulacji potwierdziły, że proponowany schemat jest efektywny dla zarządzanie femtokomórką kognitywną LTE.
6
Content available remote Porównanie metod rozpoznania otoczenia radiowego w kognitywnych sieciach sensorowych w obecności zakłóceń niegaussowskich
Konopko K.
Przegląd Elektrotechniczny
|
2017
|
R. 93, nr 12
30--33
PL
Intensywny rozwój systemów mobilnych powoduje, że statyczne metody alokacji częstotliwości przestają gwarantować rozwój aplikacji wymagających transmisji bezprzewodowej. W wyniku tego poszukiwane są innowacyjne techniki umożliwiające dynamiczny dostęp do zasobów radiowych. Podstawową metodą dynamicznego dostępu jest współdzielenie częstotliwości pomiędzy użytkownikami posiadającymi licencję, a użytkownikami nielicencjonowanymi. Użytkownik wtórny uzyskuje dostęp do niezajętych zasobów w czasie gdy użytkownik pierwotny jest nieaktywny. Omówiona metoda stanowi podstawę tzw. radia kognitywnego [1] - [3] i wymaga właściwych metod analizy dostępności zasobów częstotliwościowych przez użytkownika wtórnego i odpowiednio szybkich algorytmów podejmowania decyzji o nadawaniu i zwolnieniu pasma gdy zostanie wykryta transmisja użytkownika pierwotnego. W artykule przedstawiono numeryczne wyniki porównania różnych metod rozpoznania otoczenia radiowego wykorzystywanych do wykrywania transmisji sygnałów zgodnych ze standardem 802.11 w obecności zakłóceń o charakterze gaussowskim i niegaussowskim.
EN
It becomes observable that the current static frequency allocation schemes cannot provide sufficient requirements of an increasing number of applications requiring wireless transmission. As a result, innovative techniques that can offer new methods of sharing the available spectrum are needed. One of the most effective methods to solve this problem is allowing the secondary users to utilize the frequency band licensed to the primary users, only if it can be ensured that the band is not being currently used by the primary users. Cognitive radio [1]-[3] is the technology that implement of spectrum sensing to ensure that another users are not present before data transmission can begin. The paper presents the numerical simulation results for comparison of various spectrum sensing methods used for detection of 802.11 frame transmission in Gaussian and non-Gaussian noise.
7
An efficient resource allocation algorithm with QoS requirements in multicarrier-based cognitive radio networks
Martyna J.
Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne
|
2016
|
nr 8-9
1076--1080, CD
EN
An orthogonal frequency-division multipleaccess-based cognitive radio (CR) network is considered in this study, where primary users (PUs) dynamically sense the spectrum and opportunistically use the available channels. The objective is to maximise the CR network throughput under the PUs maximum interference constraint. The optimal resource allocation problem for this network with QoS requirements is presented and an algorithm is proposed. Simulations confirm that the proposed algorithm is nearly the optimal solution.
PL
W artykule przedstawiono kognitywne sieci radiowe z modulacją OFDMA, w których licencjonowani użytkownicy (PUs) mogą badać widmo elektromagnetyczne i wykorzystywać dostępne kanały transmisji. W artykule sformułowano problem maksymalizacji przepustowości kognitywnej sieci radiowej, uwzględniając ograniczenia powodowane zakłóceniami i wymaganiami transmisji multimedialnej. Jako rozwiązanie problemu przedstawionoalgorytm alokacji zasobów. Przeprowadzona symulacja potwierdziła, że zaproponowany algorytm jest prawie optymalnym rozwiązaniem tego zagadnienia.
8
Content available Probability of Secrecy Outage in Cognitive Radio Networks over Rician-Fading Channels
Zhang J., Jiang H., Pan G.
International Journal of Electronics and Telecommunications
|
2016
|
Vol. 62, No. 2
153--158
EN
In Rician-fading scenario, cognitive radio networks (CRNs) with a source in a secondary system transmitting its confidential information to a legitimate destination in the presence of an eavesdropper, are considered in this paper. Under CRNs, the interference power reaching at primary user (PU) is limited by some pre-defined threshold. Secrecy outage not only occurs when the achievable secrecy capacity for source-destination link is smaller than a target rate, but also occurs in the case that the interference power at PU is greater than that threshold. Analytical expression for secrecy outage probability has been derived and verified with simulation results. In addition, we have also derived the analytical expression for probability of non-zero secrecy capacity.
9
Content available Performance Evaluation of Cognitive Radio Network Based on 2-D Markov Chain
Islam M. I., Rabbi M. F., Khan R. T., Akhter J.
Journal of Telecommunications and Information Technology
|
2015
|
nr 3
39--44
EN
The objective of cognitive radio network is to enhance the wireless network spectrum utilization. In such a network, two types of users are enlisted, namely primary user (PU) and secondary user (SU). The PU can access any channel in case of its availability, but SU users have lower priority and can access a channel only when it is unused by PUs. The performance of such a network solely depends on two traffic parameters: probability of false alarm and probability of misdetection. In this paper the performance of such a network is analyzed based on two dimensional Markov chain including those parameters. The main contribution of this paper is to evaluate blocking probability and PU and SU throughput using the state transition chain instead of existing statistical analysis.
10
Content available Cooperative games with incomplete information for Secondary Base Stations in cognitive radio networks
Martyna J.
Journal of Telecommunications and Information Technology
|
2013
|
nr 3
106--111
EN
Cognitive radio (CR) technology is considered to be an effective solution for enhancing overall spectrum efficiency. Using CR technology fully involves the providing of incentives to Primary Radio Networks (PRNs) and revenue to the service provider so that Secondary Base Stations (SBSs) may utilize PRN spectrum bands accordingly. In this paper, a cooperative games with incomplete information for SBSs in a CR network is presented. Each SBS can cooperate with neighboring SBSs in order to improve its view of the spectrum. Moreover, proposed game-theory models assume that the devices have incomplete information about their components, meaning that some players do not completely know the structure of the game. Using the proposed algorithm, each SBS can leave or join the coalition while maximizing its overall utility. The simulation results illustrate that the proposed algorithm allows us to reduce the average payoff per SBS up to 140% relative to a CR network without cooperation among SBSs.
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