• Title, Summary, Keyword: spectrum

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A Cooperative Spectrum Sensing and Dynamic Spectrum Decision Methods for Heterogeneous Cognitive Radio Network (이종 인지 라디오 네트워크에서 협력 스펙트럼 센싱 및 동적 스펙트럼 결정 방법)

  • Kim, Nam-Sun
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.37 no.7A
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    • pp.560-568
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    • 2012
  • Spectrum sensing and spectrum decision are the main functions that cognitive radios (CRs) have to perform in order to get the best available spectrum band for the establishment of a wireless communication. These problems are worsened in the presence of users with different demands and spectrum channels with different properties in a heterogeneous network. The primary objective in this work is to design and simulate a new spectrum decision algorithm for heterogeneous cognitive radio system. To this end, first, we consider all cognitive users are separated into different traffic classes according to their Quality of Service (QoS). The cognitive users within one traffic class perform spectrum sensing in centralized group-based cooperative spectrum sensing system and the users of different traffic classes share the sensing results. Second, we propose a novel use of the Analytic Hierarchy Process (AHP) to optimally select available bands according to user requirements and detected spectrum channel characteristics (SCC). In this paper, utility function is used as spectrum decision algorithm. Simulation results demonstrate that the proposed method shows can effectively select the best available spectrum channels with a low complexity.

Seismic Fragility Assessment of NPP Containment Structure based on Conditional Mean Spectra for Multiple Earthquake Scenarios (다중 지진 시나리오를 고려한 원전 격납구조물의 조건부 평균 스펙트럼 기반 지진취약도 평가)

  • Park, Won Ho;Park, Ji-Hun
    • Journal of the Earthquake Engineering Society of Korea
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    • v.23 no.6
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    • pp.301-309
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    • 2019
  • A methodology to assess seismic fragility of a nuclear power plant (NPP) using a conditional mean spectrum is proposed as an alternative to using a uniform hazard response spectrum. Rather than the single-scenario conditional mean spectrum, which is the conventional conditional mean spectrum based on a single scenario, a multi-scenario conditional mean spectrum is proposed for the case in which no single scenario is dominant. The multi-scenario conditional mean spectrum is defined as the weighted average of different conditional mean spectra, each one of which corresponds to an individual scenario. The weighting factors for scenarios are obtained from a deaggregation of seismic hazards. As a validation example, a seismic fragility assessment of an NPP containment structure is performed using a uniform hazard response spectrum and different single-scenario conditional mean spectra and multi-scenario conditional mean spectra. In the example, the number of scenarios primarily influences the median capacity of the evaluated structure. Meanwhile, the control frequency, a key parameter of a conditional mean spectrum, plays an important role in reducing logarithmic standard deviation of the corresponding fragility curves and corresponding high confidence of low probability of failure (HCLPF) capacity.

Energy Detection Based Sensing for Secure Cognitive Spectrum Sharing in the Presence of Primary User Emulation Attack

  • Salem, Fatty M.;Ibrahim, Maged H.;Ibrahim, I.I.
    • IEIE Transactions on Smart Processing and Computing
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    • v.2 no.6
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    • pp.357-366
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    • 2013
  • Spectrum sensing, as a fundamental functionality of Cognitive Radio (CR), enables Secondary Users (SUs) to monitor the spectrum and detect spectrum holes that could be used. Recently, the security issues of Cognitive Radio Networks (CRNs) have attracted increasing research attention. As one of the attacks against CRNs, a Primary User Emulation (PUE) attack compromises the spectrum sensing of CR, where an attacker monopolizes the spectrum holes by impersonating the Primary User (PU) to prevent SUs from accessing the idle frequency bands. Energy detection is often used to sense the spectrum in CRNs, but the presence of PUE attack has not been considered. This study examined the effect of PUE attack on the performance of energy detection-based spectrum sensing technique. In the proposed protocol, the stationary helper nodes (HNs) are deployed in multiple stages and distributed over the coverage area of the PUs to deliver spectrum status information to the next stage of HNs and to SUs. On the other hand, the first stage of HNs is also responsible for inferring the existence of the PU based on the energy detection technique. In addition, this system provides the detection threshold under the constraints imposed on the probabilities of a miss detection and false alarm.

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Dynamic Spectrum Allocation Algorithm for Maritime Communications using Spectrum Sharing and Priority (해상무선통신환경에서 스펙트럼 공유와 우선순위를 적용한 동적스펙트럼할당 알고리즘 기술연구)

  • Lim, Moo-Sung;Kim, Kyung-Sung;Lee, Yeon-Woo;Lee, Seong-Ro
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.35 no.7B
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    • pp.1001-1008
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    • 2010
  • In this paper, we propose the dynamic spectrum allocation (DSA) algorithm using spectrum sharing method considering the long-term priority between NOs and service classes for the maritime communication system environment where a ship locates at either near shore (or land) or off-shore. It was shown that the proposed algorithm using spectrum sharing with priorities could deliver better satisfaction ratio (SR) than the fixed allocation schemes, in the context of provision of required bandwidth (or spectrum) for each users. Therefore, we conclude that the proposed DSA with priorities could apply to the maritime communication environment and exploit the under-used (or unused, idle) spectrum of terrestrial communication networks.

Dynamic Spectrum Load Balancing for Cognitive Radio in Frequency Domain and Time Domain

  • Chen, Ju-An;Sohn, Sung-Hwan;Gu, Jun-Rong;Kim, Jae-Moung
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.8 no.3
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    • pp.71-82
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    • 2009
  • As a solution to spectrum under-utilization problem, Cognitive radio (CR) introduces a dynamic spectrum access technology. In the area, one of the most important problems is how secondary users (SUs) should choose between the available channels, which means how to achieve load balancing between channels. We consider spectrum load balancing problem for CR system in frequency domain and especially in time domain. Our objective is to balance the load among the channels and balance the occupied time length of slots for a fixed channel dynamically in order to obtain a user-optimal solution. In frequency domain, we refer to Dynamic Noncooperative Scheme with Communication (DNCOOPC) used in distributed system and a distributed Dynamic Spectrum Load Balancing algorithm (DSLB) is formed based on DNCOOPC. In time domain, Spectrum Load Balancing method with QoS support is proposed based on Dynamic Feed Back theory and Hash Table (SLBDH). The performance of DSLB and SLBDH are evaluated. In frequency domain, DSLB is more efficient compared with existing Compare_And_Balance (CAB) algorithm and gets more throughput compared with Spectrum Load Balancing (SLB) algorithm. Also, DSLB is a fair scheme for all devices. In time domain, SLBDH is an efficient and precise solution compared with Spectrum Load Smoothing (SLS) method.

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Spectrum Sensing for Cognitive Radio Networks Based on Blind Source Separation

  • Ivrigh, Siavash Sadeghi;Sadough, Seyed Mohammad-Sajad
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.7 no.4
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    • pp.613-631
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    • 2013
  • Cognitive radio (CR) is proposed as a key solution to improve spectral efficiency and overcome the spectrum scarcity. Spectrum sensing is an important task in each CR system with the aim of identifying the spectrum holes and using them for secondary user's (SU) communications. Several conventional methods for spectrum sensing have been proposed such as energy detection, matched filter detection, etc. However, the main limitation of these classical methods is that the CR network is not able to communicate with its own base station during the spectrum sensing period and thus a fraction of the available primary frame cannot be exploited for data transmission. The other limitation in conventional methods is that the SU data frames should be synchronized with the primary network data frames. To overcome the above limitations, here, we propose a spectrum sensing technique based on blind source separation (BSS) that does not need time synchronization between the primary network and the CR. Moreover, by using the proposed technique, the SU can maintain its transmission with the base station even during spectrum sensing and thus higher rates are achieved by the CR network. Simulation results indicate that the proposed method outperforms the accuracy of conventional BSS-based spectrum sensing techniques.

Efficient Spectrum Sensing for Multi-Copter (멀티콥터를 위한 효율적인 스펙트럼 센싱)

  • Jung, Kuk Hyun;Lee, Sun Yui;Park, Ji Ho;Kim, Jin Young
    • Journal of Satellite, Information and Communications
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    • v.9 no.4
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    • pp.20-25
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    • 2014
  • In this paper, we provide efficient spectrum sensing technology for smooth use of frequency and energy charge of multi-copter. The proposed structures focus on improving performance of spectrum sensing that is based on Ad-hoc network. First, we explain basic principles and disadvantages of cooperative spectrum sensing and ad-hoc based spectrum sensing. To solve these problems, in this paper, we employ the beamforming technology that guarantees higher transmit primary users' signal power to secondary users in ad-hoc network. The performance of proposed algorithm is analyzed in terms of detection probabilities, and the results of this paper can be applied to the various ad-hoc based Cognitive Radio system.

SAR Image Processing Using SVD-Pseudo Spectrum Technique (SAR에 적용된 SVD-Pseudo Spectrum 기술)

  • Kim, Binhee;Kong, Seung-Hyun
    • Journal of the Institute of Electronics and Information Engineers
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    • v.50 no.3
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    • pp.212-218
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    • 2013
  • This paper presents an SVD(Singular Value Decomposition)-Pseudo Spectrum method for SAR (Synthetic Aperture Radar) imaging. The purpose of this work is to improve resolution and target separability of SAR images. This paper proposes SVD-Pseudo Spectrum method whose advantages are noise robustness, reduction of sidelobes and high resolution of spectral estimation. SVD-Pseudo Spectrum method uses Hankel Matrix of signal components and SVD (Singular Value Decomposition) method. In this paper, it is demonstrated that the SVD-Pseudo Spectrum method shows better performance than the matched filtering method and the conventional super-resolution based multiple signal classification (MUSIC) method in SAR image processing. The targets to be separated are modeled, and this modeled data is used to demonstrate the performance of algorithms.

A Study on a Next Generation Mobile Telecommunication Spectrum (차세대 이동통신 주파수에 대한 연구)

  • Lee, Hyun-Beom;Lee, Byung-Moo;You, Heung-Ryeol
    • 한국정보통신설비학회:학술대회논문집
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    • pp.166-170
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    • 2008
  • In 2006, ITU-R estimated the spectrum requirements for IMT-Advanced including IMT-2000 and its enhancements. And WRC-07 indentified four new spectrum bands for IMT system. Based on these results, there are many activities which are related with IMT system and its spectrum inside and outside of the country. This paper covers the next generation mobile telecommunication spectrum issues and outlook for the future of it.

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Complexity based Sensing Strategy for Spectrum Sensing in Cognitive Radio Networks

  • Huang, Kewen;Liu, Yimin;Hong, Yuanquan;Mu, Junsheng
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.13 no.9
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    • pp.4372-4389
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    • 2019
  • Spectrum sensing has attracted much attention due to its significant contribution to idle spectrum detection in Cognitive Radio Networks. However, specialized discussion is on complexity-based sensing strategy for spectrum sensing seldom considered. Motivated by this, this paper is devoted to complexity-based sensing strategy for spectrum sensing. Firstly, three efficiency functions are defined to estimate sensing efficiency of a spectrum scheme. Then a novel sensing strategy is proposed given sensing performance and computational complexity. After that, the proposed sensing strategy is extended to energy detector, Cyclostationary feature detector, covariance matrix detector and cooperative spectrum detector. The proposed sensing strategy provides a novel insight into sensing performance estimation for its consideration of both sensing capacity and sensing complexity. Simulations analyze three efficiency functions and optimal sensing strategy of energy detector, Cyclostationary feature detector and covariance matrix detector.