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    Wyświetlanie 1-39 z 39
    Tytuł:
    Mathematical Foundations of Cognitive Radios
    Autorzy:
    Couillet, R.
    Debbah, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/308175.pdf
    Data publikacji:
    2009
    Wydawca:
    Instytut Łączności - Państwowy Instytut Badawczy
    Tematy:
    Bayesian inference
    cognitive radio
    maximum entropy
    Opis:
    Recently, much interest has been directed towards software defined radios and embedded intelligence in telecommunication devices. However, no fundamental basis for cognitive radios has ever been proposed. In this paper, we introduce a fundamental vision of cognitive radios from a physical layer viewpoint. Specifically, our motivation in this work is to embed human-like intelligence in mobile wireless devices, following the three century-old work on Bayesian probability theory, the maximum entropy principle and minimal probability update. This allows us to partially answer such questions as, what are the signal detection capabilities of a wireless device, when facing a situation in which most parameters are missing, how to react and so on. As an introductory example, we will present previous works from the same authors following the cognitive framework, and especially the multi-antenna channel modeling and signal sensing.
    Źródło:
    Journal of Telecommunications and Information Technology; 2009, 4; 108-117
    1509-4553
    1899-8852
    Pojawia się w:
    Journal of Telecommunications and Information Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Optimal Voting Rule and Minimization of Total Error Rate in Cooperative Spectrum Sensing for Cognitive Radio Networks
    Autorzy:
    Ghosh, Samit Kumar
    Trankatwar, Sachin Ravikant
    Bachan, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/1839471.pdf
    Data publikacji:
    2021
    Wydawca:
    Instytut Łączności - Państwowy Instytut Badawczy
    Tematy:
    cognitive radio
    energy detection
    optimization
    spectrum sensing
    Opis:
    In cognitive radio technology, spectrum sensing is essential for detecting spectrum holes which may be allotted to secondary users. In this paper, an optimal voting rule is used for cooperative spectrum sensing while minimizing the total error rate (TER). The proposed spectrum sensing method is more energy-efficient and may be implemented in practice. It is relied upon in an improved energy detector whose utilization depends on the presence or absence of the primary user. Expressions for false alarm and missed detection probabilities are derived in the paper as well. Overall performance is analyzed both for AWGN and Rayleigh fading channels, in the presence of additive white Gaussian noise (AWGN). The optimum voting rule is applied to the cooperative spectrum sensing process in order to identify the optimum number of sensing nodes and the detection threshold. Finally, an energy-efficient spectrum sensing algorithm is proposed, requiring a lower number of cognitive users for a given error bound.
    Źródło:
    Journal of Telecommunications and Information Technology; 2021, 1; 43-50
    1509-4553
    1899-8852
    Pojawia się w:
    Journal of Telecommunications and Information Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Optimal Voting Rule and Minimization of Total Error Rate in Cooperative Spectrum Sensing for Cognitive Radio Networks
    Autorzy:
    Ghosh, Samit Kumar
    Trankatwar, Sachin Ravikant
    Bachan, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/1839487.pdf
    Data publikacji:
    2021
    Wydawca:
    Instytut Łączności - Państwowy Instytut Badawczy
    Tematy:
    cognitive radio
    energy detection
    optimization
    spectrum sensing
    Opis:
    In cognitive radio technology, spectrum sensing is essential for detecting spectrum holes which may be allotted to secondary users. In this paper, an optimal voting rule is used for cooperative spectrum sensing while minimizing the total error rate (TER). The proposed spectrum sensing method is more energy-efficient and may be implemented in practice. It is relied upon in an improved energy detector whose utilization depends on the presence or absence of the primary user. Expressions for false alarm and missed detection probabilities are derived in the paper as well. Overall performance is analyzed both for AWGN and Rayleigh fading channels, in the presence of additive white Gaussian noise (AWGN). The optimum voting rule is applied to the cooperative spectrum sensing process in order to identify the optimum number of sensing nodes and the detection threshold. Finally, an energy-efficient spectrum sensing algorithm is proposed, requiring a lower number of cognitive users for a given error bound.
    Źródło:
    Journal of Telecommunications and Information Technology; 2021, 1; 43-50
    1509-4553
    1899-8852
    Pojawia się w:
    Journal of Telecommunications and Information Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Implementation of Selected Spectrum Sensing Systems for Cognitive Radio Networks using FPGA Platform
    Autorzy:
    Abdullah, H. N.
    Abed, H. S.
    Powiązania:
    https://bibliotekanauki.pl/articles/958080.pdf
    Data publikacji:
    2018
    Wydawca:
    Instytut Łączności - Państwowy Instytut Badawczy
    Tematy:
    cognitive radio
    energy consumption
    energy detection
    FPGA
    Opis:
    The energy efficient spectrum sensing method is very important in cognitive radio (CR), since high power drain may limit its implementation in mobile applications. The spectrum sensing feature consumes more energy than other functional blocks, as it depends on continuous detection of the presence or absence of the primary user (PU). In this paper, we proposed two methods to reduce energy consumption of the spectrum sensing feature. The first is of a single stage variety with a reduced number of sensed samples. The other uses two stages. The first stage performs coarse sensing for many subchannels, and the best subchannel is forwarded for fine sensing in the second stage. The performance of the proposed methods is evaluated in AWGN channel and compared with the existing approach. The proposed methods are simulated using Matlab and ModelSim and are then hardware implemented using the Altera Cyclone II FPGA board. Simulation results show that the proposed methods offer an improvement in energy consumption with an acceptable reduction in the probability of detection. At Eb/N0 Eb/N0 Eb/N0 of 0 dB, the energy consumption is reduced by 50% and 72% in the first and second proposed method, respectively, compared to the traditional method (100% sensing).
    Źródło:
    Journal of Telecommunications and Information Technology; 2018, 4; 81-87
    1509-4553
    1899-8852
    Pojawia się w:
    Journal of Telecommunications and Information Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    About Cognitive Radio Receiver under an Indoor Environment
    Autorzy:
    González, Ricardo Meneses
    Powiązania:
    https://bibliotekanauki.pl/articles/1193910.pdf
    Data publikacji:
    2015
    Wydawca:
    Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
    Tematy:
    Cognitive radio
    indoor environment
    spectrum hole
    white space
    Opis:
    This small note makes an analysis of the current situation of the Cognitive Radio (CR) performance under an indoor environment. As well as, measurements of the electromagnetic environment in the 800-900 MHz UHF Band are carried out in a specific indoor environment, in order to discover a spectrum hole to be used by an cognitive radio unlicensed user.
    Źródło:
    World Scientific News; 2015, 22; 1-13
    2392-2192
    Pojawia się w:
    World Scientific News
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Radio Environment Map for the Cognitive Radio Network Simulator
    Autorzy:
    Bednarek, P.
    Bicki, D.
    Lopatka, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/226843.pdf
    Data publikacji:
    2018
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    cognitive radio
    Radio Environment Maps
    REM database
    G-REM
    L-REM
    Opis:
    Military wireless tactical systems has faced the problem of limited spectrum resources. This is a reason why Cognitive Radio (CR) is one of the most popular topic studied by research institutes in the field of mobile telecommunications. CR technology is based on cognitive cycle, used for making decisions based on observation and orientation. To support this activity, radios need also information on current position, electromagnetic situation, legal issues etc. These functions can be provided by Radio Environment Map (REM) database. It enables more flexible spectrum utilization and coexistence of Primary and Secondary Users (PUs, SUs) without harmful interferences. This paper presents a proposal of REM database structure and graphical user interface (GUI). It also describes GUI implementation in MATLAB and data structure. Database was implemented using the database engine - SQLite. The proposed REM database is a part of cognitive radio network simulator developed in the Institute of Telecommunications.
    Źródło:
    International Journal of Electronics and Telecommunications; 2018, 64, 1; 45-49
    2300-1933
    Pojawia się w:
    International Journal of Electronics and Telecommunications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    ICBCA – Improved Cluster Based Channel Allocation in Cognitive Radio Sensor Networks
    Autorzy:
    Agarkhed, Jayashree
    Gatate, Veeranna
    Powiązania:
    https://bibliotekanauki.pl/articles/308481.pdf
    Data publikacji:
    2020
    Wydawca:
    Instytut Łączności - Państwowy Instytut Badawczy
    Tematy:
    channel interference
    channel overlapping
    co-channel interference
    cognitive radio
    Opis:
    Wireless sensor networks (WSNs) operate in an overcrowded electromagnetic environment, as the spectrum is shared by various wireless communication technologies. This gives rise to various challenges related to optimized and efficient spectrum utilization. Cognitive radio (CR) has emerged as a solution satisfying this requirement, as it is capable of adapting to the dynamic radio spectrum. Thanks to the deployment of cognitive radio in WSNs, the spectrum may be utilized in a more efficient manner. CR may identify the vacant channels dynamically, allowing the sensor nodes to effeectively communicate with each other. In this paper a clustering algorithm known as improved cluster-based channel assignment (ICBCA) is implemented, forming clusters of CR sensor nodes and then selecting vacant channels for data transmission purposes. Simulation results show that ICBCA outperforms existing clustering algorithms in CR sensor networks.
    Źródło:
    Journal of Telecommunications and Information Technology; 2020, 3; 28-35
    1509-4553
    1899-8852
    Pojawia się w:
    Journal of Telecommunications and Information Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Power Allocation for Energy-Harvesting-based Fading Cognitive Multiple Access Channels : with or without Successive Interference Cancellation
    Autorzy:
    Li, Q.
    Xu, D.
    Powiązania:
    https://bibliotekanauki.pl/articles/963855.pdf
    Data publikacji:
    2017
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    cognitive radio
    power allocation
    multiple access channels
    energy harvesting
    Opis:
    This paper considers a fading cognitive multiple access channel (CMAC), where multiple secondary users (SUs), who share the spectrum with a primary user (PU), transmit to a cognitive base station (CBS). A power station is assumed to harvest energy from the nature and then provide power to the SUs. We investigate the power allocation problems for such a CMAC to maximize the SU sum rate under the interference power constraint, the sum transmit power constraint and the peak transmit power constraint of each individual SU. In particular, two scenarios are considered: with successive interference cancellation (SIC) and without SIC. For the first scenario, the optimal power allocation algorithm is derived. For the second scenario, a heuristic algorithm is proposed. We show that the proposed algorithm with SIC outperforms the algorithm without SIC in terms of the SU sum rate, while the algorithm without SIC outperforms the algorithm with SIC in terms of the number of admitted SUs for a high sum transmit power limit and a low peak transmit power limit of each individual SU.
    Źródło:
    International Journal of Electronics and Telecommunications; 2017, 63, 1; 65-72
    2300-1933
    Pojawia się w:
    International Journal of Electronics and Telecommunications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Optimization of Spectrum Sensing Parameters in Cognitive Radio Using Adaptive Genetic Algorithm
    Autorzy:
    Chatterjee, S.
    Dutta, S.
    Bhattacharya, P. P.
    Roy, J. S.
    Powiązania:
    https://bibliotekanauki.pl/articles/308511.pdf
    Data publikacji:
    2017
    Wydawca:
    Instytut Łączności - Państwowy Instytut Badawczy
    Tematy:
    adaptive genetic algorithm
    bandwidth
    cognitive radio
    spectrum sensing
    throughput
    Opis:
    Quality of service parameters of cognitive radio, like, bandwidth, throughput and spectral efficiency are optimized using adaptive and demand based genetic algorithm. Simulation results show that the proposed method gives better real life solution to the cognitive radio network than other known approach.
    Źródło:
    Journal of Telecommunications and Information Technology; 2017, 1; 21-27
    1509-4553
    1899-8852
    Pojawia się w:
    Journal of Telecommunications and Information Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Cooperative games with incomplete information for Secondary Base Stations in cognitive radio networks
    Autorzy:
    Martyna, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/308673.pdf
    Data publikacji:
    2013
    Wydawca:
    Instytut Łączności - Państwowy Instytut Badawczy
    Tematy:
    Bayesian equilibrium
    cognitive radio networks
    game theory
    wireless communication
    Opis:
    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.
    Źródło:
    Journal of Telecommunications and Information Technology; 2013, 3; 106-111
    1509-4553
    1899-8852
    Pojawia się w:
    Journal of Telecommunications and Information Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    On Employing a Savitzky-Golay Filtering Stage to Improve Performance of Spectrum Sensing in CR Applications Concerning VDSA Approach
    Autorzy:
    Angrisani, L.
    Capriglione, D.
    Cerro, G.
    Ferrigno, L.
    Miele, G.
    Powiązania:
    https://bibliotekanauki.pl/articles/220369.pdf
    Data publikacji:
    2016
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    cognitive radio
    smoothing filter
    VDSA
    spectrum sensing
    spectral measurements
    Opis:
    In this paper, a filtering stage based on employing a Savitzky-Golay (SG) filter is proposed to be used in the spectrum sensing phase of a Cognitive Radio (CR) communication paradigm for Vehicular Dynamic Spectrum Access (VDSA). It is used to smooth the acquired spectra, which constitute the input for a spectrum sensing algorithm. The sensing phase is necessary, since VDSA is based on an opportunistic approach to the spectral resource, and the opportunities are represented by the user-free spectrum zones, to be detected through the sensing phase. Each filter typology presents peculiarities in terms of its computational cost, de-noising ability and signal shape reconstruction. The SG filtering properties are compared with those of the linear Moving Average (MA) filter, widely used in the CR framework. Important improvements are proposed.
    Źródło:
    Metrology and Measurement Systems; 2016, 23, 2; 295-308
    0860-8229
    Pojawia się w:
    Metrology and Measurement Systems
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Mobility-Aware, Correlation-Based Node Grouping and Selection for Cooperative Spectrum Sensing
    Autorzy:
    Cichoń, K.
    De Nardis, L.
    Bogucka, H.
    Di Benedetto, M. G.
    Powiązania:
    https://bibliotekanauki.pl/articles/307964.pdf
    Data publikacji:
    2014
    Wydawca:
    Instytut Łączności - Państwowy Instytut Badawczy
    Tematy:
    cognitive radio
    cooperative spectrum sensing
    mobility
    node grouping
    node selection
    Opis:
    Cooperative spectrum sensing has been proposed as a solution to increase the sensing function accuracy in cognitive radio networks, but the research has, so far, mainly focused on static scenarios, all but neglecting the impact of mobility on spectrum sensing. In this work a novel cooperative spectrum sensing scheme for mobile cognitive networks, based on a correlation-based, mobility-aware node selection algorithm is proposed. Correlation among sensing decisions is used to divide nodes into groups, and mobility is taken into account in the group leaders selection by means of a node selection metric that considers both sensing performance and mobility. Performance of the proposed algorithm is evaluated by computer simulations taking into account mobility and a detailed modeling of temporal and spatial correlation of fading and shadowing components in the channel path loss, going way beyond the performance evaluation carried out in previous works on correlation-based cooperative sensing schemes. Simulation results highlight that the proposed metric leads to a signicant increase of the update period required to maintain acceptable sensing performance, and correspondingly to a strong reduction in the overhead caused by the grouping and node selection procedure.
    Źródło:
    Journal of Telecommunications and Information Technology; 2014, 2; 90-102
    1509-4553
    1899-8852
    Pojawia się w:
    Journal of Telecommunications and Information Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Suboptimal Approach to Distributed Detection in Cognitive Radio Networks
    Autorzy:
    Kumari, Shweta
    Praveena, Sirimilla
    Powiązania:
    https://bibliotekanauki.pl/articles/1839473.pdf
    Data publikacji:
    2021
    Wydawca:
    Instytut Łączności - Państwowy Instytut Badawczy
    Tematy:
    cognitive radio
    distributed detection
    energy detector
    myopic policy
    spectrum sensing
    Opis:
    In this paper a dynamic spectrum access (DSA) concept is explored for mitigating the paucity of spectral bandwidth in cognitive radio (CR) for opportunistic, dynamic access of the spectrum without any interference. Dynamic spectrum access schemes are proposed for a distributed cognitive radio network consisting of one secondary user (SU) and many primary users (PUs). The SU has to make decisions for accessing PU channels within discrete time slots. The design of sensing and access strategies that govern channel choice in each slot for near-optimal throughput performance of the SU may be formulated as a partially observable Markov decision process (POMDP). Furthermore, it is considered that the SU incurs a cost whenever it switches to a different channel. The switching cost is expressed in terms of delay, packet loss and packet overhead. In this work, the SU access policy based on a myopic approach is proposed and evaluated.
    Źródło:
    Journal of Telecommunications and Information Technology; 2021, 1; 32-36
    1509-4553
    1899-8852
    Pojawia się w:
    Journal of Telecommunications and Information Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Integrating Two Feedback Queuing Discipline into Cognitive Radio Channel Aggregation
    Autorzy:
    Esenogho, E.
    Mambou, E. N.
    Ferreira, H. C.
    Powiązania:
    https://bibliotekanauki.pl/articles/226390.pdf
    Data publikacji:
    2018
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    cognitive radio
    channel aggregation
    primary and secondary users
    queue discipline
    Opis:
    Queuing regime is one outstanding approach in improving channel aggregation. If well designed and incorporated with carefully selected parameters, it enhances the smooth rollout of fifth/next generation wireless networks. While channel aggregation is the merging of scattered TV white space (spectrum holes) into one usable chunk for secondary users (SU). The queuing regime ensures that these unlicensed users (SUs) traffic/services are not interrupted permanently (blocked/dropped or forced to terminate) in the event of the licensed users (primary user) arrival. However, SUs are not identical in terms of traffic class and bandwidth consumption hence, they are classified as real time and non-real time SU respectively. Several of these strategies have been studied considering queuing regime with a single feedback queuing discipline. In furtherance to previous proposed work with single feedback queuing regime, this paper proposes, develops and compares channel aggregation policies with two feedback queuing regimes for the different classes of SUs. The investigation aims at identifying the impacts of the twofeedback queuing regime on the performance of the secondary network such that any SU that has not completed its ongoing service are queued in their respective buffers. The performance is evaluated through a simulation framework. The results validate that with a well-designed queuing regime, capacity, access and other indices are improved with significant decrease in blocking and forced termination probabilities respectively.
    Źródło:
    International Journal of Electronics and Telecommunications; 2018, 64, 4; 519-525
    2300-1933
    Pojawia się w:
    International Journal of Electronics and Telecommunications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Perspektywy zagospodarowania widma radiowego w Polsce pod kątem implementacji radia kognitywnego
    Spectrum management prospects in Poland in terms of the implementation of cognitive radio
    Autorzy:
    Grzybkowski, M. J.
    Powiązania:
    https://bibliotekanauki.pl/articles/317416.pdf
    Data publikacji:
    2012
    Wydawca:
    Instytut Łączności - Państwowy Instytut Badawczy
    Tematy:
    radio kognitywne
    widmo częstotliwości radiowych
    zakresy częstotliwości
    cognitive radio
    radio spectrum
    frequency bands
    Opis:
    W artykule przeanalizowano zakresy częstotliwości, które mogą być wykorzystane w systemach radia kognitywnego, przy założeniu obecnych i planowanych przeznaczeń częstotliwości w Polsce (w tym także w kontekście przeznaczeń europejskich) oraz istniejącego planu zagospodarowania poszczególnych zakresów częstotliwości. Analizę przeprowadzono uwzględniając możliwość wprowadzenia sieci radia kognitywnego w wybranych częściach widma, w tym w pasmach licencjonowanych oraz nielicencjonowanych, w sposób scentralizowany lub rozproszony.
    The article analyzes the frequency bands which can be used by cognitive radio systems in the future, assuming the current and planned frequency allocation in Poland (including in the context of recommended European common allocations), and the existing frequency management plan. The analysis has been performed taking into account the possibility of implementation of cognitive radio networks in some parts of the radio spectrum, including licensed and unlicensed frequency bands., by the centralized or distributed method.
    Źródło:
    Telekomunikacja i Techniki Informacyjne; 2012, 1-2; 18-39
    1640-1549
    1899-8933
    Pojawia się w:
    Telekomunikacja i Techniki Informacyjne
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Suboptimal Approach to Distributed Detection in Cognitive Radio Networks
    Autorzy:
    Kumari, Shweta
    Praveena, Sirimilla
    Powiązania:
    https://bibliotekanauki.pl/articles/1839486.pdf
    Data publikacji:
    2021
    Wydawca:
    Instytut Łączności - Państwowy Instytut Badawczy
    Tematy:
    cognitive radio
    distributed detection
    energy detector
    myopic policy
    spectrum sensing
    Opis:
    In this paper a dynamic spectrum access (DSA) concept is explored for mitigating the paucity of spectral bandwidth in cognitive radio (CR) for opportunistic, dynamic access of the spectrum without any interference. Dynamic spectrum access schemes are proposed for a distributed cognitive radio network consisting of one secondary user (SU) and many primary users (PUs). The SU has to make decisions for accessing PU channels within discrete time slots. The design of sensing and access strategies that govern channel choice in each slot for near-optimal throughput performance of the SU may be formulated as a partially observable Markov decision process (POMDP). Furthermore, it is considered that the SU incurs a cost whenever it switches to a different channel. The switching cost is expressed in terms of delay, packet loss and packet overhead. In this work, the SU access policy based on a myopic approach is proposed and evaluated.
    Źródło:
    Journal of Telecommunications and Information Technology; 2021, 1; 32-36
    1509-4553
    1899-8852
    Pojawia się w:
    Journal of Telecommunications and Information Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    An Efficient Cooperative Spectrum Sensing Method Using Renyi Entropy Weighted Optimal Likelihood Ratio for CRN
    Autorzy:
    Shrote, Sandip B.
    Poshattiwa, Sadhana D.
    Powiązania:
    https://bibliotekanauki.pl/articles/24200748.pdf
    Data publikacji:
    2023
    Wydawca:
    Instytut Łączności - Państwowy Instytut Badawczy
    Tematy:
    cognitive radio
    eigen statistics
    optimal weight
    signal energy
    spectrum sensing
    Opis:
    The main concept behind employing cognitive radio is to enable secondary users (SUs) or unlicensed users to utilize the available spectrum. Spectrum sensing methods detect the existence of primary users (PUs) and have become the main topic of research in the CRN industry and in academia. This paper proposes a new framework based on the Adam gradient descent (Adam GD) algorithm to develop a spectrum sensing mechanism used in CRNs and detecting the availability of free channels. The signal's components are extracted from the received signal and the spectrum is searched for availability which is detected through a fusion center using the proposed algorithm. The proposed Adam GD algorithm attains the maximum detection probability rate and the minimum false alarm probability of 0.71 and 0.39, respectively, for a Rayleigh channel.
    Źródło:
    Journal of Telecommunications and Information Technology; 2023, 3; 41--48
    1509-4553
    1899-8852
    Pojawia się w:
    Journal of Telecommunications and Information Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Evaluation of Radio Channel Utility using Epsilon-Greedy Action Selection
    Autorzy:
    Malon, Krzysztof
    Powiązania:
    https://bibliotekanauki.pl/articles/1839337.pdf
    Data publikacji:
    2021
    Wydawca:
    Instytut Łączności - Państwowy Instytut Badawczy
    Tematy:
    cognitive radio
    dynamic spectrum access
    spectrum monitoring
    machine learning
    Q-learning
    Opis:
    This paper presents an algorithm that supports the dynamic spectrum access process in cognitive radio networks by generating a sorted list of best radio channels or by identifying those frequency ranges that are not in use temporarily. The concept is based on the reinforcement learning technique named Q-learning. To evaluate the utility of individual radio channels, spectrum monitoring is performed. In the presented solution, the epsilon-greedy action selection method is used to indicate which channel should be monitored next. The article includes a description of the proposed algorithm, scenarios, metrics, and simulation results showing the correct operation of the approach relied upon to evaluate the utility of radio channels and the epsilon-greedy action selection method. Based on the performed tests, it is possible to determine algorithm parameters that should be used in this proposed deployment. The paper also presents a comparison of the results with two other action selection methods.
    Źródło:
    Journal of Telecommunications and Information Technology; 2021, 3; 10-17
    1509-4553
    1899-8852
    Pojawia się w:
    Journal of Telecommunications and Information Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Deep Learning-based SNR Estimation for Multistage Spectrum Sensing in Cognitive Radio Networks
    Autorzy:
    Jeevangi, Sanjeevkumar
    Jawaligi, Shivkumar
    Patil, Vilaskumar
    Powiązania:
    https://bibliotekanauki.pl/articles/2174451.pdf
    Data publikacji:
    2022
    Wydawca:
    Instytut Łączności - Państwowy Instytut Badawczy
    Tematy:
    cognitive radio
    improved NMF
    LU-SLNO system
    optimized CNN
    spectrum sensing
    Opis:
    Vacant frequency bands are used in cognitive radio (CR) by incorporating the spectrum sensing (SS) technique. Spectrum sharing plays a central role in ensuring the effectiveness of CR applications. Therefore, a new multi-stage detector for robust signal and spectrum sensing applications is introduced here. Initially, the sampled signal is subjected to SNR estimation by using a convolutional neural network (CNN). Next, the detection strategy is selected in accordance with the predicted SNR levels of the received signal. Energy detector (ED) and singular value-based detector (SVD) are the solutions utilized in the event of high SNR, whilst refined non-negative matrix factorization (MNMF) is employed in the case of low SNR. CNN weights are chosen via the Levy updated sea lion optimization (LU-SLNO) algorithm inspired by the traditional sea lion optimization (SLNO) approach. Finally, the outcomes of the selected detectors are added, offering a precise decision on spectrum tenancy and existence of the signal.
    Źródło:
    Journal of Telecommunications and Information Technology; 2022, 4; 21--32
    1509-4553
    1899-8852
    Pojawia się w:
    Journal of Telecommunications and Information Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    OFDM for Cognitive Radio Systems : Novel Power Allocation and Bit Loading Algorithms
    Autorzy:
    Razmi, Shirin
    Parhizgar, Naser
    Powiązania:
    https://bibliotekanauki.pl/articles/227256.pdf
    Data publikacji:
    2019
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    cognitive radio
    OFDM
    interference constraints
    power allocation
    adaptive modulation
    bit loading
    Opis:
    A novel method to improve the performance of the frequency band is cognitive radio that was introduced in 1999. Due to a lot of advantages of the OFDM, adaptive OFDM method, this technique is used in cognitive radio (CR) systems, widely. In adaptive OFDM, transmission rate and power of subcarriers are allocated based on the channel variations to improve the system performance. This paper investigates adaptive resource allocation in the CR systems that are used OFDM technique to transmit data. The aim of this paper is to maximize the achievable transmission rate for the CR system by considering the interference constraint. Although secondary users can be aware form channel information between each other, but in some wireless standards, it is impossible for secondary user to be aware from channel information between itself and a primary user. Therefore, due to practical limitation, statistical interference channel is considered in this paper. This paper introduces a novel suboptimal power allocation algorithm. Also, this paper introduces a novel bit loading algorithm. In the numerical results sections, the performance of our algorithm is compared by optimal and conventional algorithms. Numerical results indicate our algorithm has better performance than conventional algorithms while its complexity is less than optimal algorithm.
    Źródło:
    International Journal of Electronics and Telecommunications; 2019, 65, 1; 139-145
    2300-1933
    Pojawia się w:
    International Journal of Electronics and Telecommunications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Energy-based spectrum sensing with copulas for cognitive radios
    Autorzy:
    Ilgin, F. Y.
    Powiązania:
    https://bibliotekanauki.pl/articles/201847.pdf
    Data publikacji:
    2020
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    energy-based sensing
    cognitive radio
    copula theory
    Neyman Pearson
    spectrum management
    Opis:
    In this study, an energy-based spectrum sensing method combined with copula theory is proposed for cognitive radio systems. In the proposed spectrum sensing model, cognitive radio users first make their own local spectrum decision with energy-based spectrum sensing. Then, they forward their decision to the fusion center. In the fusion center, this decision is compared with the threshold value determined by copula theory and global spectrum decision is made. The test statistic at the fusion center were obtained with the Neyman Pearson approach. Thus, the fusion rule was created for the fusion center and necessary simulation studies were performed. According to the results of the simulation studies, the proposed detection method showed better results than the traditional energy based detection method.
    Źródło:
    Bulletin of the Polish Academy of Sciences. Technical Sciences; 2020, 68, 4; 829-834
    0239-7528
    Pojawia się w:
    Bulletin of the Polish Academy of Sciences. Technical Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Cooperative Spectrum Sensing in Cognitive Radio Networks: A Survey on Machine Learning-based Methods
    Autorzy:
    Khamayseh, Sundous
    Halawani, Alaa
    Powiązania:
    https://bibliotekanauki.pl/articles/308079.pdf
    Data publikacji:
    2020
    Wydawca:
    Instytut Łączności - Państwowy Instytut Badawczy
    Tematy:
    cognitive radio
    cooperative spectrum sensing
    IEEE 802.22
    machine learning
    spectrum sensing
    Opis:
    The continuous growth of demand experienced by wireless networks creates a spectrum availability challenge. Cognitive radio (CR) is a promising solution capable of overcoming spectrum scarcity. It is an intelligent radio technology that may be programmed and dynamically configured to avoid interference and congestion in cognitive radio networks (CRN). Spectrum sensing (SS) is a cognitive radio life cycle task aiming to detect spectrum holes. A number of innovative approaches are devised to monitor the spectrum and to determine when these holes are present. The purpose of this survey is to investigate some of these schemes which are constructed based on machine learning concepts and principles. In addition, this review aims to present a general classification of these machine learningbased schemes.
    Źródło:
    Journal of Telecommunications and Information Technology; 2020, 3; 36-46
    1509-4553
    1899-8852
    Pojawia się w:
    Journal of Telecommunications and Information Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Dual Port Antenna Combining Sensing and Communication Tasks for Cognitive Radio
    Autorzy:
    Nachouane, H.
    Najid, A.
    Tribak, A.
    Riouch, F.
    Powiązania:
    https://bibliotekanauki.pl/articles/226370.pdf
    Data publikacji:
    2016
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    cognitive radio
    microstrip antenna
    UWB
    coplanar waveguide
    sensing and communication tasks
    sensing antenna
    Opis:
    Dynamic spectrum access has been proposed as the effective solution to overcome the spectrum scarcity issue, supported by cognitive radio technology. Sensing and communication functions are both the most important tasks in cognitive radio systems. In this paper, an antenna system combining sensing and communication tasks is proposed to be integrated into cognitive radio front-ends. The sensing task is performed by means of an ultra-wideband quasi-omnidirectional antenna. Whilst the communication task is ensured by using a narrowband antenna. Both antennas have been designed on the same layer of an FR4 substrate, for manufacturing cost constraint. Therefore, the isolation between them must take into consideration. The measured mutual coupling of less than -18 dB is achieved over the whole impedance bandwidth. The proposed sensing antenna covers a wide range frequency bands ranging from 2 to 5.5 GHz. While the communication antenna operates at 2.8 GHz, and by adding inductors to the antenna, the resonant frequency can be tuned from 2.6 to 2.7 GHz. The whole antenna system was designed, fabricated, and tested. Measurement and simulation results prove the feasibility of the proposed structure for cognitive radio applications.
    Źródło:
    International Journal of Electronics and Telecommunications; 2016, 62, 2; 121-127
    2300-1933
    Pojawia się w:
    International Journal of Electronics and Telecommunications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    On the Evaluation of Handover Exchange Schemes Between Two Cognitive Radio Base Stations with and without Buffers
    Autorzy:
    Esenogho, E.
    Mambou, E. N.
    Ferreira, H. C.
    Powiązania:
    https://bibliotekanauki.pl/articles/226444.pdf
    Data publikacji:
    2018
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    cognitive radio networks
    channel handover exchange scheme
    blocking probability
    force termination
    handover failure
    Opis:
    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.
    Źródło:
    International Journal of Electronics and Telecommunications; 2018, 64, 4; 513-518
    2300-1933
    Pojawia się w:
    International Journal of Electronics and Telecommunications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Cognitive network model dedicated to transport system telematics
    Autorzy:
    Gajewska, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/393207.pdf
    Data publikacji:
    2014
    Wydawca:
    Polskie Stowarzyszenie Telematyki Transportu
    Tematy:
    cognitive green radio
    cognitive network model
    sensor
    telematics
    czujnik
    telematyka
    Opis:
    The paper defines the concept of cognitive radio in the context of transport systems, with particular emphasis on modern ecological concept of “green cognitive radio”. In addition, in the paper a modified cognitive network model dedicated to transport system telematics is proposed and presented. Algorithms to support the functioning of the cognitive radio are discussed. Sensors necessary to use the network to support cognitive functioning of transport system telematics are defined. The use of cognitive networks in transport is proposed.
    Źródło:
    Archives of Transport System Telematics; 2014, 7, 2; 34-39
    1899-8208
    Pojawia się w:
    Archives of Transport System Telematics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Performance Analysis of the Cognitive Radio Network with Opportunistic Spectrum Access
    Autorzy:
    Chęciński, R.
    Kaszuba-Chęcińska, A.
    Kryk, M.
    Łopatka, J.
    Malon, K.
    Skokowski, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/226072.pdf
    Data publikacji:
    2018
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    MANET
    cognitive radio
    dynamic spectrum access
    USRP
    RF switch matix
    real time demonstrator
    Opis:
    Efficient access to the spectral resources becomes a challenge for future military wireless communication systems. It requires spectral situation awareness, knowledge of current regulations, local policies and hardware platform limitations. It can be achieved by cognitive radios, realizing cognitive cycle, consisting typically of continuous observation, orientation, reasoning and decision making. All these elements must be realized in parallel and shouldn't interfere with each other. Even more difficult issue is related with cooperation between different nodes, especially in wireless domain, in harsh propagation conditions. Unpredictable phenomena create hard conditions for all deterministic behavior models, and their reproduction is a key element for efficient operation of the network. Very popular computer simulations are always simplified, and real time implementation gives an opportunity to make the next step in system elaboration. This paper presents a real-time demonstrator of cognitive radio network. It can work both in wired mode, using radio channel emulator and in mobile mode, to verify influence of real conditions on proposed cognitive solutions and assess their effectiveness.
    Źródło:
    International Journal of Electronics and Telecommunications; 2018, 64, 1; 51-56
    2300-1933
    Pojawia się w:
    International Journal of Electronics and Telecommunications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Improving the Efficiency of UAV Communication Channels in the Context of Electronic Warfare
    Autorzy:
    Semendiai, Serhii
    Tkach, Yuliіa
    Shelest, Mykhailo
    Korchenko, Oleksander
    Ziubina, Ruslana
    Veselska, Olga
    Powiązania:
    https://bibliotekanauki.pl/articles/27311946.pdf
    Data publikacji:
    2023
    Wydawca:
    Polska Akademia Nauk. Czasopisma i Monografie PAN
    Tematy:
    cognitive radio
    software-defined radio
    neural networks
    coding
    electronic warfare
    communication channel
    wireless communications
    spectrum analysis
    Opis:
    The article is devoted to the development of a method for increasing the efficiency of communication channels of unmanned aerial vehicles (UAVs) in the conditions of electronic warfare (EW). The author analyses the threats that may be caused by the use of electronic warfare against autonomous UAVs. A review of some technologies that can be used to create original algorithms for countering electronic warfare and increasing the autonomy of UAVs on the battlefield is carried out. The structure of modern digital communication systems is considered. The requirements of unmanned aerial vehicle manufacturers for onboard electronic equipment are analyzed, and the choice of the hardware platform of the target radio system is justified. The main idea and novelty of the proposed method are highlighted. The creation of a model of a cognitive radio channel for UAVs is considered step by step. The main steps of modelling the spectral activity of electronic warfare equipment are proposed. The main criteria for choosing a free spectral range are determined. The type of neural network for use in the target cognitive radio system is substantiated. The idea of applying adaptive coding in UAV communication channels using multicomponent turbo codes in combination with neural networks, which are simultaneously used for cognitive radio, has been further developed.
    Źródło:
    International Journal of Electronics and Telecommunications; 2023, 69, 4; 727--732
    2300-1933
    Pojawia się w:
    International Journal of Electronics and Telecommunications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Performance Evaluation of Cognitive Radio Network Based on 2-D Markov Chain
    Autorzy:
    Islam, M. I.
    Rabbi, M. F.
    Khan, R. T.
    Akhter, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/958115.pdf
    Data publikacji:
    2015
    Wydawca:
    Instytut Łączności - Państwowy Instytut Badawczy
    Tematy:
    cognitive radio networks
    misdetection
    probability of false alarm
    throughput and traffic of limited channel
    Opis:
    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.
    Źródło:
    Journal of Telecommunications and Information Technology; 2015, 3; 39-44
    1509-4553
    1899-8852
    Pojawia się w:
    Journal of Telecommunications and Information Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Probability of Secrecy Outage in Cognitive Radio Networks over Rician-Fading Channels
    Autorzy:
    Zhang, J.
    Jiang, H.
    Pan, G.
    Powiązania:
    https://bibliotekanauki.pl/articles/226243.pdf
    Data publikacji:
    2016
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    cognitive radio networks
    wiretap
    Rician fading
    secrecy outage probability
    probability of non-zero secrecy capacity
    Opis:
    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.
    Źródło:
    International Journal of Electronics and Telecommunications; 2016, 62, 2; 153-158
    2300-1933
    Pojawia się w:
    International Journal of Electronics and Telecommunications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Optimal Spectrum Sensor Assignment in Multi-channel Multi-user Cognitive Radio Networks
    Autorzy:
    Nandini, K. S.
    Hariprasad, S. A.
    Powiązania:
    https://bibliotekanauki.pl/articles/308326.pdf
    Data publikacji:
    2018
    Wydawca:
    Instytut Łączności - Państwowy Instytut Badawczy
    Tematy:
    channel accessibility matrix
    cognitive radio networks
    optimal assignment
    probability of interference
    secondary users
    spectrum sensing
    Opis:
    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.
    Źródło:
    Journal of Telecommunications and Information Technology; 2018, 4; 88-96
    1509-4553
    1899-8852
    Pojawia się w:
    Journal of Telecommunications and Information Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Multi-objective Channel Decision for Adhoc Cognitive Radio Network
    Autorzy:
    Awathankar, Rahul V
    Rukmini, M S S
    Raut, Rajeshree D
    Powiązania:
    https://bibliotekanauki.pl/articles/226079.pdf
    Data publikacji:
    2019
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    cognitive radio networks
    ranking and optimization
    cooperative network
    channel decision
    multi objective decision making(MODM)
    MOORA method
    Opis:
    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.
    Źródło:
    International Journal of Electronics and Telecommunications; 2019, 65, 2; 253-257
    2300-1933
    Pojawia się w:
    International Journal of Electronics and Telecommunications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Nowe możliwości liberalizacji sektora telekomunikacyjnego w aspekcie technik kognitywnych
    New possibilities of liberalization of telecommunication sector in the context of cognitive technologies
    Autorzy:
    Burdziak, Anna
    Grzybkowski, Maciej J.
    Więcek, Dariusz
    Powiązania:
    https://bibliotekanauki.pl/articles/508387.pdf
    Data publikacji:
    2012-11-26
    Wydawca:
    Uniwersytet Warszawski. Wydawnictwo Naukowe Wydziału Zarządzania
    Tematy:
    telekomunikacja
    widmo radiowe
    zarządzanie widmem radiowym
    regulacje prawne
    zarządzanie częstotliwościami radiowymi
    radio kognitywne
    telecommunication law
    radio spectrum management
    legal regulations
    cognitive radio (CR)
    Opis:
    Celem niniejszego artykułu jest przedstawienie nowych możliwości liberalizacji sektora telekomunikacyjnego poprzez wykorzystanie nowatorskich technik radia kognitywnego (ang. Cognitive Radio) – będących jeszcze w fazie badawczo-rozwojowej, z którymi jednak wiązane są największe nadzieje na zmianę dotychczasowego sposobu gospodarki widmem. W pierwszej części artykułu przedstawiona jest dotychczasowa liberalizacja sektora telekomunikacyjnego oraz regulacje prawne dotyczące widma radiowego. Następnie omówione zostały techniki kognitywne ze szczególnym naciskiem na ich cechy umożliwiające bardziej elastyczne i efektywne wykorzystanie widma. Wcielenie w życie kognitywnych technik radiowych będzie wymagało zarówno zmiany istniejących regulacji prawnych jak i wprowadzenia nowych. Proponowane zmiany mają charakter hipotetyczny i zależne są od ostatecznych wyników prac na radiem kognitywnym. W artykule przedstawione są zarówno zagrożenia jak i szanse jakie niesie ze sobą wprowadzenie w życie technik radia kognitywnego. Potencjalnie najbardziej pożądanym skutkiem będzie przejście ze statycznego na dynamiczne zarządzanie widmem radiowym.
    The aim of this paper is to present new possibilities of liberalization of Telecommunications Sector using an innovative cognitive technology (Cognitive Radio-CR), which are still in phase of research and development, and which however, are the biggest hope for changing current way of radio spectrum management. The first part of this paper presents the existing liberalization of Telecommunication Sector and legal regulations regarding radio spectrum management. Second part of this paper contains discussion of the cognitive technologies focusing on features of CR, with special emphasis on their characteristics for more flexible and more efficient use of radio spectrum. Implementation of cognitive technologies would result in a need of changing current legal regulations as well as in creating new ones. Changes proposed in this paper are provisional and are dependent on final results of scientific research in the cognitive radio area. This paper presents both risks and opportunities resulting from implementation of cognitive radio technologies. The most desirable potential result would be switchover from static to dynamic radio spectrum management.
    Źródło:
    internetowy Kwartalnik Antymonopolowy i Regulacyjny; 2012, 1, 5; 24-39
    2299-5749
    Pojawia się w:
    internetowy Kwartalnik Antymonopolowy i Regulacyjny
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Theoretical Investigation of Different Diversity Combining Techniques in Cognitive Radio
    Autorzy:
    Agarwal, R.
    Srivastava, N.
    Katiyar, H.
    Powiązania:
    https://bibliotekanauki.pl/articles/309425.pdf
    Data publikacji:
    2018
    Wydawca:
    Instytut Łączności - Państwowy Instytut Badawczy
    Tematy:
    cognitive radio
    complementary ROC
    post examining selection
    probability of detection
    probability of false alarm
    switch combining
    examine combining
    Opis:
    In this paper, the performance of an energy detector in cognitive radio, using different diversity combining techniques, is evaluated. Among many diversity combining techniques, maximal ratio combining (MRC) gives the best results but at the cost of the highest complexity. To design a simpler receiver, it is suggested to use less complex combining techniques, i.e. switched diversity, which provides one of the least complex solutions to combat fading. The paper analyzes two switched diversity schemes, switch examine combining (SEC), and switch examine combining with post examining selection (SECp). A closed form expression determining the probability of detection using MRC, SEC and SECp is derived for various numbers of branches. Detection performance with different diversity combining techniques is compared and the complexity trade-off is observed.
    Źródło:
    Journal of Telecommunications and Information Technology; 2018, 3; 64-69
    1509-4553
    1899-8852
    Pojawia się w:
    Journal of Telecommunications and Information Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Space-Time-Frequency Machine Learning for Improved 4G/5G Energy Detection
    Autorzy:
    Wasilewska, Małgorzata
    Bogucka, Hanna
    Powiązania:
    https://bibliotekanauki.pl/articles/226216.pdf
    Data publikacji:
    2020
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    spectrum sensing
    cognitive radio
    machine learning
    energy detection
    4G
    LTE
    5G
    k-nearest neighbors
    random forest
    Opis:
    In this paper, the future Fifth Generation (5G New Radio) radio communication system has been considered, coexisting and sharing the spectrum with the incumbent Fourth Generation (4G) Long-Term Evolution (LTE) system. The 4G signal presence is detected in order to allow for opportunistic and dynamic spectrum access of 5G users. This detection is based on known sensing methods, such as energy detection, however, it uses machine learning in the domains of space, time and frequency for sensing quality improvement. Simulation results for the considered methods: k-Nearest Neighbor sand Random Forest show that these methods significantly improves the detection probability.
    Źródło:
    International Journal of Electronics and Telecommunications; 2020, 66, 1; 217-223
    2300-1933
    Pojawia się w:
    International Journal of Electronics and Telecommunications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The application of software defined radios in unmanned aerial vehicles
    Zastosowanie radiostacji definiowanych programowo (software defined radios) w bezpilotowych środkach powietrznych
    Autorzy:
    Błachut, Marek
    Pogorzelec, Piotr
    Powiązania:
    https://bibliotekanauki.pl/articles/29551729.pdf
    Data publikacji:
    2022
    Wydawca:
    Akademia Wojsk Lądowych imienia generała Tadeusza Kościuszki
    Tematy:
    software defined radio
    unmanned aerial vehicle
    troposcatter communications
    cognitive radio
    spectrum occupancy
    radio definiowane programowo
    bezzałogowy statek powietrzny
    łączność troposferyczna
    radio kognitywne
    zajętość widma częstotliwości
    Opis:
    The article addresses the application of software defined radios (SDR) on modern battlefields. Above all, it focuses on the application of the SDR technology in communication with unmanned aerial vehicles. It also reviews some solutions applied in the armed forces of Finland, United States, Poland, Turkey, and Israel. It outlines the potential of these solutions and considers the main direction of development of the SDR technology, which is the cognitive radio.
    W artykule odniesiono się do wykorzystania na współczesnym polu walki radiostacji definiowanych programowo (SDR). Przede wszystkim skupiono się na wykorzystaniu technologii SDR do komunikowania się z bezpilotowymi środkami powietrznymi (BSP). Dokonano także przeglądu niektórych rozwiązań funkcjonujących w siłach zbrojnych Finlandii, Stanów Zjednoczonych, Polski, Turcji oraz Izraela. Po prezentacji możliwości wcześniej wspomnianych rozwiązań przedstawiono rozważania nad podstawowym kierunkiem rozwoju technologii SDR – radiem kognitywnym.
    Źródło:
    Scientific Journal of the Military University of Land Forces; 2022, 54, 3(205); 375-396
    2544-7122
    2545-0719
    Pojawia się w:
    Scientific Journal of the Military University of Land Forces
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Full-duplex Cognitive Radio NOMA Networks : Outage and Throughput Performance Analysis
    Autorzy:
    Tran, Thanh-Nam
    Do, Dinh-Thuan
    Voznak, Miroslav
    Powiązania:
    https://bibliotekanauki.pl/articles/226091.pdf
    Data publikacji:
    2019
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    Non-Orthogonal Multiple Access (NOMA)
    Cognitive Radio (CR)
    full-duplex (FD)
    outage probability
    system throughput
    achievabe bit rate
    Opis:
    A novel non-orthogonal multiple access (NOMA) scheme is proposed to improve the throughput and the outage probability of the cognitive radio (CR) inspired system which has been implemented to adapt multiple services in the next-generation network (5G). In the proposed scheme, the primary source (PS) had sent a superposition code symbol with a predefined power allocation to relays, it decoded and forwarded (DF) a new superposition coded symbol to the destination with the other power allocation. By using a dual antenna at relays, it will be improved the bandwidth efficiency in such CR NOMA scheme. The performance of the system is evaluated based on the outage probability and the throughput with the assumption of the Rayleigh fading channels. According to the results obtained, it is shown that the outage probability and throughput of the proposed full-duplex (FD) in CR-NOMA with reasonable parameters can be able deploy in practical design as illustration in numerical results section.
    Źródło:
    International Journal of Electronics and Telecommunications; 2019, 65, 1; 103-109
    2300-1933
    Pojawia się w:
    International Journal of Electronics and Telecommunications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Wirtualna zajętość widma w sieciach radia kognitywnego - algorytmy oceny
    Virtual Channel Occupancy in Cognitive Radio Networks: Evaluation Algorithms
    Autorzy:
    Strużak, R.
    Sobolewski, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/317604.pdf
    Data publikacji:
    2014
    Wydawca:
    Instytut Łączności - Państwowy Instytut Badawczy
    Tematy:
    radio kognitywne
    intermodulacje
    zarządzanie widmem
    inżynieria widma
    wzbogacanie widma
    kompatybilność elektromagnetyczna
    wirtualna zajętość
    kanały radiowe
    prawdopodobieństwo zakłóceń
    regulacje radiowe
    cognitive radio
    interference
    intermodulation
    spectrum management
    spectrum engineering
    spectrum enrichment
    electromagnetic compatibility
    virtual channel occupancy
    probability of interference
    regulations
    Opis:
    Artykuł zawiera ogólny przegląd problemów związanych z inżynierią widma w aspekcie radia kognitywnego, bez wiązania go z jakąkolwiek specyficzną technologią, zakresem częstotliwości lub zastosowaniem. Zajętość taka jest powodowana nieliniowościami w elementach toru transmisyjnego i w otoczeniu. Omawia się w nim podstawowe mechanizmy oraz dyskutuje problemy praktycznego wykorzystania tej nowej technologii. Przedstawia się dwa algorytmy, z których jeden pozwala odpowiedzieć na pytanie, czy dany kanał częstotliwości może być wykorzystany przez radio kognitywne w konkretnej sytuacji. Przytacza się wyniki badań symulacyjnych pokazujące, że wirtualna zajętość może znacznie ograniczać pulę dostępnych kanałów. Drugi algorytm pozwala oszacować prawdopodobieństwo tego rodzaju efektów nieliniowych przy koegzystencji systemów radiowych na danym obszarze geograficznym. Chociaż został on opracowany dla innego zastosowania radia (tzw. CB - citizen band) autorzy proponują, aby zaadaptować go dla potrzeb radia kognitywnego. Dotychczas, przy wyznaczaniu obszarów potencjalnego zastosowania radia kognitywnego nie brano pod uwagę wirtualnej zajętości ani nie zwracano uwagi na konieczność oddzielnego planowanie częstotliwości dla kanałów nadawania i dla kanałów odbioru w radiu kognitywnym. Wspomina się związane z tematem wcześniejsze badania Instytutu Łączności i proponuje się dalsze prace.
    This article reviews problems of virtual occupancy of radio spectrum from the perspective of cognitive radio. It is quite general and does not imply any specific technology, application, or frequency. Such occupancy results from nonlinearities in radio transmitters and receivers and in their neighborhood. The process is known also as intermodulation or spectrum enrichment. The paper discusses its mechanisms and problems it creates for practical application of cognitive radio. Then it describes two general algorithms. One of them, answering the question whether or not a given frequency channel can be exploited by cognitive radio to assure its interference free operation, was used in Australia. Simulation results are quoted, which show that the pool of channels available for a cognitive radio can be substantially reduced due to virtual occupancy. The second algorithm calculates the probability of intermodulation interference over a geographical region shared by radio systems. It was originally used in the USA to determine that probability for the "citizen band radio". The authors propose it to be adapter to the case of cognitive radio systems. The article does mention also research undertaken earlier in the EMC Labs. of the National Institute of Telecommunications in Wroclaw in that area and propose their continuation.
    Źródło:
    Telekomunikacja i Techniki Informacyjne; 2014, 1-2; 33-48
    1640-1549
    1899-8933
    Pojawia się w:
    Telekomunikacja i Techniki Informacyjne
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Cognitive Qualities of Radio Reportage in the Light of Scientific Research
    Autorzy:
    Czarnek-Wnuk, Paulina
    Powiązania:
    https://bibliotekanauki.pl/articles/649675.pdf
    Data publikacji:
    2016
    Wydawca:
    Uniwersytet Łódzki. Wydawnictwo Uniwersytetu Łódzkiego
    Tematy:
    cognitive qualities
    radio broadcasting
    radio reportage
    Opis:
    Despite the fact that radio documentaries broadcast mainly strong emotions, the news valu of this genre is also an essential feature. Therefore, it is necessary to describe the potential of such works to expand knowledge about the surrounding world which could be significant for the listeners. The aim of this article is to present theses put forward by scholars with regard to radio documentaries. Researchers’ analyses are related to the genre’s potential to broaden people’s minds and influence the recipient’s perception.
    Źródło:
    Acta Universitatis Lodziensis. Folia Litteraria Polonica; 2016, 35, 5
    1505-9057
    2353-1908
    Pojawia się w:
    Acta Universitatis Lodziensis. Folia Litteraria Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Time-slot based architecture for power beam-assisted relay techniques in CR-WSNs with transceiver hardware inadequacies
    Autorzy:
    Umer, Mushtaq Muhammad
    Jiang, Hong
    Zhang, Qiuyun
    Manlu, Liu
    Muhammad, Owais
    Powiązania:
    https://bibliotekanauki.pl/articles/27311438.pdf
    Data publikacji:
    2023
    Wydawca:
    Polska Akademia Nauk. Czasopisma i Monografie PAN
    Tematy:
    cognitive radio WSNs
    energy harvesting
    DF relaying
    relay selection schemes in WSNs
    hardware inadequacy in WSNs
    wireless sensor networks
    zbieranie energii
    bezprzewodowa sieć czujników
    WSN
    sieci radia kognitywnego
    przekaz DF
    bezprzewodowe sieci sensoryczne
    Opis:
    Over the past two decades, numerous research projects have concentrated on cognitive radio wireless sensor networks (CR-WSNs) and their benefits. To tackle the problem of energy and spectrum shortfall in CR-WSNs, this research proposes an underpinning decode-&-forward (DF) relaying technique. Using the suggested time-slot architecture (TSA), this technique harvests energy from a multi-antenna power beam (PB) and delivers source information to the target utilizing energy-constrained secondary source and relay nodes. The study considers three proposed relay selection schemes: enhanced hybrid partial relay selection (E-HPRS), conventional opportunistic relay selection (C-ORS), and leading opportunistic relay selection (L-ORS). We present evidence for the sustainability of the suggested methods by examining the outage probability (OP) and throughput (TPT) under multiple primary users (PUs). These systems leverage time switching (TS) receiver design to increase end-to-end performance while taking into account the maximum interference constraint and transceiver hardware inadequacies. In order to assess the efficacy of the proposed methods, we derive the exact and asymptotic closed-form equations for OP and TPT & develop an understanding to learn how they affect the overall performance all across the Rayleigh fading channel. The results show that OP of the L-ORS protocol is 16% better than C-ORS and 75% better than E-HPRS in terms of transmitting SNR. The OP of L-ORS is 30% better than C-ORS and 55% better than E-HPRS in terms of hardware inadequacies at the destination. The L-ORS technique outperforms C-ORS and E-HPRS in terms of TPT by 4% and 11%, respectively.
    Źródło:
    Bulletin of the Polish Academy of Sciences. Technical Sciences; 2023, 71, 5; art. no. e146620
    0239-7528
    Pojawia się w:
    Bulletin of the Polish Academy of Sciences. Technical Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
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