16,776 research outputs found
Improved Spectrum Mobility using Virtual Reservation in Collaborative Cognitive Radio Networks
Cognitive radio technology would enable a set of secondary users (SU) to
opportunistically use the spectrum licensed to a primary user (PU). On the
appearance of this PU on a specific frequency band, any SU occupying this band
should free it for PUs. Typically, SUs may collaborate to reduce the impact of
cognitive users on the primary network and to improve the performance of the
SUs. In this paper, we propose and analyze the performance of virtual
reservation in collaborative cognitive networks. Virtual reservation is a novel
link maintenance strategy that aims to maximize the throughput of the cognitive
network through full spectrum utilization. Our performance evaluation shows
significant improvements not only in the SUs blocking and forced termination
probabilities but also in the throughput of cognitive users.Comment: 7 pages, 10 figures, IEEE ISCC 201
Distributed Cooperative Sensing in Cognitive Radio Networks: An Overlapping Coalition Formation Approach
Cooperative spectrum sensing has been shown to yield a significant
performance improvement in cognitive radio networks. In this paper, we consider
distributed cooperative sensing (DCS) in which secondary users (SUs) exchange
data with one another instead of reporting to a common fusion center. In most
existing DCS algorithms, the SUs are grouped into disjoint cooperative groups
or coalitions, and within each coalition the local sensing data is exchanged.
However, these schemes do not account for the possibility that an SU can be
involved in multiple cooperative coalitions thus forming overlapping
coalitions. Here, we address this problem using novel techniques from a class
of cooperative games, known as overlapping coalition formation games, and based
on the game model, we propose a distributed DCS algorithm in which the SUs
self-organize into a desirable network structure with overlapping coalitions.
Simulation results show that the proposed overlapping algorithm yields
significant performance improvements, decreasing the total error probability up
to 25% in the Q_m+Q_f criterion, the missed detection probability up to 20% in
the Q_m/Q_f criterion, the overhead up to 80%, and the total report number up
to 10%, compared with the state-of-the-art non-overlapping algorithm
Spectrum sharing models in cognitive radio networks
Spectrum scarcity demands thinking new ways to
manage the distribution of radio frequency bands so that its use is more effective. The emerging technology that can enable this paradigm shift is the cognitive radio. Different models for
organizing and managing cognitive radios have emerged, all with specific strategic purposes. In this article we review the allocation spectrum patterns of cognitive radio networks and
analyse which are the common basis of each model.We expose the vulnerabilities and open challenges that still threaten the adoption
and exploitation of cognitive radios for open civil networks.L'escassetat de demandes d'espectre fan pensar en noves formes de gestionar la distribució de les bandes de freqüència de ràdio perquè el seu ús sigui més efectiu. La tecnologia emergent que pot permetre aquest canvi de paradigma és la ràdio cognitiva. Han sorgit diferents models d'organització i gestió de les ràdios cognitives, tots amb determinats fins estratègics. En aquest article es revisen els patrons d'assignació de l'espectre de les xarxes de ràdio cognitiva i s'analitzen quals són la base comuna de cada model. S'exposen les vulnerabilitats i els desafiaments oberts que segueixen amenaçant l'adopció i l'explotació de les ràdios cognitives per obrir les xarxes civils.La escasez de demandas de espectro hacen pensar en nuevas formas de gestionar la distribución de las bandas de frecuencia de radio para que su uso sea más efectivo. La tecnología emergente que puede permitir este cambio de paradigma es la radio cognitiva. Han surgido diferentes modelos de organización y gestión de las radios cognitivas, todos con determinados fines estratégicos. En este artículo se revisan los patrones de asignación del espectro de las redes de radio cognitiva y se analizan cuales son la base común de cada modelo. Se exponen las vulnerabilidades y los desafíos abiertos que siguen amenazando la adopción y la explotación de las radios cognitivas para abrir las redes civiles
Byzantine Attack and Defense in Cognitive Radio Networks: A Survey
The Byzantine attack in cooperative spectrum sensing (CSS), also known as the
spectrum sensing data falsification (SSDF) attack in the literature, is one of
the key adversaries to the success of cognitive radio networks (CRNs). In the
past couple of years, the research on the Byzantine attack and defense
strategies has gained worldwide increasing attention. In this paper, we provide
a comprehensive survey and tutorial on the recent advances in the Byzantine
attack and defense for CSS in CRNs. Specifically, we first briefly present the
preliminaries of CSS for general readers, including signal detection
techniques, hypothesis testing, and data fusion. Second, we analyze the spear
and shield relation between Byzantine attack and defense from three aspects:
the vulnerability of CSS to attack, the obstacles in CSS to defense, and the
games between attack and defense. Then, we propose a taxonomy of the existing
Byzantine attack behaviors and elaborate on the corresponding attack
parameters, which determine where, who, how, and when to launch attacks. Next,
from the perspectives of homogeneous or heterogeneous scenarios, we classify
the existing defense algorithms, and provide an in-depth tutorial on the
state-of-the-art Byzantine defense schemes, commonly known as robust or secure
CSS in the literature. Furthermore, we highlight the unsolved research
challenges and depict the future research directions.Comment: Accepted by IEEE Communications Surveys and Tutoiral
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