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The paper proposes a customized frequency domain energy detection spectrum sensing scheme. It is needed to fulfill requirements provided by the IEEE 802.22 standard, aimed at extending Internet services to Television White Space frequencies. It provides a detection scheme allowing to achieve strict sensitivity required by the protocol either in sensing time or in detection capabilities. In particular,...
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,...
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...
This paper proposes a channel allocation scheme for Wide-Area Low-Rate Wireless Personal Area Networks (LR-WPAN) based on a cooperative centralized spectrum sensing approach. We refer here to a three-tiers LR-WPAN architecture, where we can distinguish the sensor devices level, the Child-coordinators level and, finally, the super LR-WPAN coordinator level. In the proposed scheme, channels allocation...
In this paper, we have intended and delineated about discerning the white space in the spectrum which is precious. The Cognitive Radio is transpiring because of its idiosyncratic nature of exploiting the unused spectrum for various praxis. Initially, we have discerned the unused frequencies in the TV band which comprises from 585 to 698 MHz and in the FM band which comprises from 87.5 MHz to 108.0...
Spectrum sharing based on the dedicated databases, particularly in the context of TV band, is widely considered as a promising tool for better spectrum utilization in the future wireless networks. Practical realization of this paradigm entails the need for the true protection of the incumbent system, and at the same time the guarantee of the quality of the services offered to the secondary users....
Rendezvous is a fundamental process in constructing cognitive radio networks (CRNs), in which two users find a common channel for communication. The licensed spectrum is assumed to be divided into n non-overlapping channels and the users can sense the spectrum by equipping with cognitive radios. Most of previous works assume that the user can find a set of available channels (the channels not occupied...
PU Emulsion attack is one of the most important Threats of Spectrum sensing for wireless Cognitive Radio Network. On the basis of the Wireless Signal a PU is detected in a given band, all secondary Users should avoid accessing that band. However, when a Secondary user is detected other Secondary users may choose to share that same band. In a Primary user Attack, a malicious Secondary tries to gain...
Cognitive radio (CR) is a promising technology that allows unlicensed users to access licensed spectrum bands. In the Philippines, the Information and Communications Technology Office of the Department of Science and Technology (DOST-ICTO) plans to deploy a “Super Wi-Fi” that could provide broadband access especially in rural areas by harnessing the TVWS in the country. However, the switchover to...
Continuous demand, by end users, has become an issue with respect to the scarce resources of the radio frequency spectrum. In this paper we conducted a 24-hour outdoor measurement of spectrum occupancy, in both rural and urban areas in Kwara State, Nigeria, spanning across the frequency range of 48.5 MHz – 880 MHz The results obtained show that the mean average duty cycle for TV bands 1–4 and CDMA...
Cyclostationarity-based spectrum sensing exploits the spectral correlation property of the primary user (PU) signal; hence, exhibits relative robustness against noise and interference. Existing studies on this method focus on analytical and simulation approaches. This work focuses on the experimental measurement of the performance of cyclostationarity-based spectrum sensing using a magnitude squared...
Cognitive radio is a new technology that improves spectrum utilization by allowing secondary users to use licensed channels in an opportunistic manner. Because primary users have a right to use their licensed channels at any time, it is necessary for secondary users to stop their transmissions or to continue their transmissions in other channels in case of action of primary users. The event of changing...
This article studies the problem of message dissemination in Cognitive Radio Ad Hoc (CRAHNs) over TV white bands. By exploiting the supreme propagation characteristics of low-frequency channels, this article proposes two message dissemination protocols that use acknowledged transmissions to guarantee dissemination reliability. These two protocols rely on assistance from neighboring terminals to expedite...
Cognitive Radio (CR) dynamically finds the spectrum opportunity i.e. spectrum hole in space-time-frequency and code to do its adaptive transmission without harming the incumbent or the Primary User (PU). TV white spaces (TVWS) are the unused or underutiliised bands in the UHF and VHF part of the band which according to Federal Communication Commission (FCC) can be exploited if the secondary user (SU)...
A range of applications in cognitive radio networks, from adaptive spectrum sensing to predictive spectrum mobility and dynamic spectrum access, depend on our ability to foresee the state evolution of radio spectrum, raising a fundamental question: To what degree is radio spectrum state (RSS) predictable? In this article we explore the fundamental limits of predictability in RSS dynamics by studying...
Very recently, regulatory bodies worldwide have started to approve the dynamic access of unlicensed networks to the TV White Space spectrum. Hence, in the near future, multiple heterogeneous and unlicensed ad hoc networks will coexist within the same geographical area over shared TV White Space. Although heterogeneity and coexistence are not unique to TV White Space scenarios, their distinctive characteristics...
The attractive characteristics of the TV White Space makes it the ideal candidate for enabling multiple and independently-operated secondary networks via Cognitive Radio paradigm. However, so far, there are no regulatory requirements for the coexistence among heterogenous secondary networks over TVWS. Hence, their mutual interference can be very severe. This issue is even more crucial in urban Smart...
Spectrum prediction is a promising technology to infer unknown/unmeasured spectrum state from known/measured spectrum data, by exploiting the inherent correlations among them. This paper investigates spectrum prediction from a spectral-temporal two-dimensional perspective, with the primary objective to improve the prediction performance by jointly exploiting the correlations in both time and frequency...
Recently the use of mobile devices is increasing and mobile traffic is growing rapidly. In order to deal with the massive traffic, cognitive radio (CR) is applied to efficiently use the limited spectrum resources. In this paper, we propose a CR operational algorithm for mobile cellular systems, which is applicable to the multiple secondary user environment. Performance of the proposed algorithm is...
The cognitive radio technology allows solving one of the main issues of current wireless communication technologies, namely a deficit of vacant spectrum. A dynamic spectrum access used in the cognitive radio networks (CRN) gives an ability to access to an unused spectrum in real time. Cooperative spectrum sensing is the most effective method for spectrum holes detecting. It combines sensing information...
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