Serwis Infona wykorzystuje pliki cookies (ciasteczka). Są to wartości tekstowe, zapamiętywane przez przeglądarkę na urządzeniu użytkownika. Nasz serwis ma dostęp do tych wartości oraz wykorzystuje je do zapamiętania danych dotyczących użytkownika, takich jak np. ustawienia (typu widok ekranu, wybór języka interfejsu), zapamiętanie zalogowania. Korzystanie z serwisu Infona oznacza zgodę na zapis informacji i ich wykorzystanie dla celów korzytania z serwisu. Więcej informacji można znaleźć w Polityce prywatności oraz Regulaminie serwisu. Zamknięcie tego okienka potwierdza zapoznanie się z informacją o plikach cookies, akceptację polityki prywatności i regulaminu oraz sposobu wykorzystywania plików cookies w serwisie. Możesz zmienić ustawienia obsługi cookies w swojej przeglądarce.
The cognitive radio positioning system requires a distributed localization algorithm, since the secondary uses (SUs) can not communication with primary users (PUs) directly. The localization algorithm should also be robust to the topology changes of SUs due to the opportunistic access nature. In this paper, we propose a distributed particle filtering method to locate the PU's position. The ranging...
Standardization activities have already begun on 5G to support very high system requirements. A common consensus toward achieving these targets is to permit transmission over a wide spectrum range. The departure from a dedicated licensed-only spectrum regime to a shared spectrum model poses new challenges for next generation mobile communication systems. Cognitive Radio Technologies is an enabler...
Traditionally, enhancing the safety of commuters and relieving traffic congestion have been the primary objectives of Vehicular Ad hoc Networks (VANETs). Recently, much progress has been made in the field of vehicular communication, enabling futuristic applications that might make journeys more enjoyable to passengers, such as exchanging multimedia among passengers in nearby vehicles. However, these...
Wideband sensing-based cognitive radio with simultaneous wireless information and power transfer can be designed for efficient spectrum and energy usage. We investigate maxmin fairness energy-harvesting optimization problem in such a system by taking into account of the individual link fairness. In particular, we maximize the energy harvested by the worstcase link when the problem is subject to the...
Recently, some papers that apply a multi-armed bandit algorithm for channel selection in a cognitive radio system have been reported. In those papers, channel selection based on Upper Confidence Bound (UCB) algorithm has been proposed. However, in those selection, secondary users are not allowed to transmit data over same channels at the same time. Moreover, they do not take security of wireless communication...
In this paper, we improve throughput performance of a cognitive radio network through a proposed dual-level sensing strategy. Throughput performance of secondary users cannot be enhanced while providing higher priority to protect primary users from secondary user interference. Therefore, we propose a novel multiple access scheme based on dual-level sensing strategy by which both the interference protection...
In cognitive radio networks (CRNs), spectrum sensing data falsification (SSDF) is one of the most typical attack which hugely degrades the detection performance of cooperative spectrum sensing (CSS). SSDF and defense strategies have been an active field of research, but countermeasures of existing researches are sensitive to the number of malicious users (MUs). In this paper, we propose a two-stage...
In this paper, we address the blind rendezvous problem of cognitive radios (CRs) quickly finding each other to establish communication in a multi-channel dynamic spectrum access (DSA) environment. We propose a multi-agent Q-learning based rendezvous strategy that allows CR-based secondary users (SUs) to actively explore a dynamic DSA environment and learn through resulting rewards which channels are...
In this paper, we propose a novel spectrum sensing method to detect the presence of a primary user in a cognitive radio network when the secondary user is employing a large number of receive antennas. The new method is a suboptimal approach based on the generalized likelihood ratio test (GLRT), but unlike the previous GLRT-based methods which rely on large number of received samples obtained over...
Nowadays, wideband spectrum sensing, as one of the vital technologies of cognitive radio (CR), has the potential to find more temporarily available frequency bands to meet the growing demands of wireless services. As the vast number of samples are required to be collected and processed, traditional wideband spectrum sensing methods become inefficient and cause large energy consumption. Therefore,...
In this paper, we use a Spectrum Sharing/allocation algorithm to implement a Cognitive Radio network without spectral awareness. This allows radio resources to be allocated to primary users and to secondary users in such a way that primary system and secondary system are aware of each other. By doing this, sensing of spectrum holes is avoided but the primary users will be protected and will always...
In the non-time-slotted cognitive radio networks (CRNs), the synchronization between PUs and secondary users (SUs) cannot be guaranteed, resulting in two challenging problems: the reactivation-failure of PUs and the frequently unexpected hand-offs among SUs. The reactivation-failure of PUs is the incident that the SUs cannot detect the PUs' reactivation when the SUs are occupying the channels to transmit...
We consider a cognitive radio network, where primary users have priority over the spectrum resources, and secondary users can exploit the unused resources through channel sensing. Due to sensing inaccuracy, the secondary traffic may obstruct the primary traffic. A penalty for collision has been used to protect the primary traffic, which is often designed to provide a fixed per-collision compensation...
We propose a cooperative cognitive system. The primary system and the cognitive system inform each other such as synchronization in frequency, phase and time. Primary user (PU) can employ orthogonal frequency division multiplexing (OFDM) modulation and the cognitive user (CU) frequency hopping (FH). We explore the scenario in which the CU and PU share the spectrum simultaneously.
A low power integrating mixer successive approximation register (SAR) prototype chip for spectrum sensing is fabricated for portable transceivers targeting IEEE 802.22 cognitive radio applications. The integrating mixer SAR combines mixing, current-domain windowing, and integration to implement the short-time Fourier transform. Integration with programmable time constant is incorporated within the...
In this paper, we study a multi-level power allocation scheme for SUs in cognitive radio systems that uses a new frame structure to improve overall throughput of the system. The scheme is different from the conventional strategies in that the PU can now transmit with multiple levels of power rather than a constant level of power, which seems to be more realistic and practical. Our proposed strategy...
Recently, the demand for faster and more reliable data transmission has brought up complex communications systems. As a result, it has become more difficult to carry out closed-form solutions that can provide insight about performance levels. In this paper, different from the existing research, we study a cognitive radio system that employs hybrid-automatic-repeat-request (HARQ) protocols under quality-of-service...
Cognitive cellular networks can enable opportunistic network access but their effectiveness relies on adaptive handoff algorithms. However, in cognitive radio networks the usufructuary rights of a secondary user are rescinded due to the unanticipated appearance of a primary user causing potential service disruption. In order to provide uninterrupted service to a cognitive cellular user, we propose...
In this paper, a new spectrum sensing (SS) method, called maximum-to-mean energy detector (MMED), is proposed. Considering a wireless communication system with many angles of arrival (AoA), the suggested method is based on beamforming and the ratio of the maximum energy to the mean one of the received signal. The proposal is totally blind and it does not require the knowledge of the signal, the channel...
To maximize spectrum access opportunities for white space devices, incorporating real-time spectrum sensing with geolocation database is a promising approach to enhance detection resolution. Advanced spectrum sensing techniques are needed to quickly and accurately identify spectrum occupancy over a wide frequency range. However, the stringent requirements from the wideband signal acquisition and processing...
Podaj zakres dat dla filtrowania wyświetlonych wyników. Możesz podać datę początkową, końcową lub obie daty. Daty możesz wpisać ręcznie lub wybrać za pomocą kalendarza.