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    Wyświetlanie 1-13 z 13
    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:
    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:
    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:
    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:
    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:
    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:
    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:
    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:
    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:
    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:
    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
      Wyświetlanie 1-13 z 13

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