• Title, Summary, Keyword: spectrum

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Policy Design to Vitalize Spectrum Sharing Ecosystem : A System Dynamics Approach (인과지도에 기반한 주파수공유 생태계 활성화 정책 설계)

  • Song, Hee Seok;Kim, Jae Kyung;Kim, Taehan
    • Journal of Information Technology Services
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    • v.13 no.4
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    • pp.109-122
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    • 2014
  • Demand of spectrum resource is tremendously increasing recently and this trend will continues in the future due to the wide spread of IT services based on cloud computing and Internet of Things technology and as well as smart devices. Recently, spectrum sharing technology has drawn attention to the spectrum policy makers as a promising way to overcome the shortage problem of scarce spectrum resource. To succeed in commercialization of spectrum sharing technology, it is necessary to prospect the future business ecosystem of spectrum sharing and develop appropriate policies and laws at the same time along with the advance of spectrum sharing technology. The purpose of this paper is to analyze casual relationships between enablers in future business ecosystem of spectrum sharing and propose policies to vitalize spectrum sharing ecosystem based on a system dynamics causal map proposed in the previous research. With the causal map and system dynamics method, it is possible to analyze feedback loops exist in the business ecosystem of spectrum sharing and build policies which optimize positive dynamics in business ecosystem of spectrum sharing. As a result, policy leverages were found in four areas; spectrum supply, spectrum demand, spectrum quality and technology, and spectrum transaction cost. For those policy leverages, 13 policies were identified and intervention timing for each policy was discussed. Finally, the promotion policies of government and market participants to vitalize spectrum sharing ecosystem were discussed.

A Novel Definition of Spectrum Holes for Improved Spectrum Utilization Efficiency

  • Li, Xiaoqiang;Zhou, Qi;Dai, Hui;Zhang, Jie;Li, Ying
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.8 no.3
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    • pp.749-761
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    • 2014
  • Improving spectrum utilization efficiency is a fundamental goal of dynamic spectrum access technology. The definition of spectrum holes determines how to detect and exploit them. Current definitions of spectrum holes are ineffective in exploiting spatial-temporal spectrum holes. In this paper, a novel definition of spectrum holes is proposed, in which throughput loss indicates the impact of secondary users on primary users. The definition specifies spectrum holes, unifies the impact of secondary users on primary users and is effective exploiting spatial-temporal spectrum holes. Theoretical analysis and numerical simulations show that the new definition proposed in this paper significantly improves the spectrum utilization efficiency.

Real Time Spectrum Markets and Interruptible Spectrum

  • Marcus Michael J.
    • Journal of Communications and Networks
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    • v.8 no.2
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    • pp.158-162
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    • 2006
  • Historically, spectrum use has been increased through use of high frequencies, improved modulation, and between antenna techniques. However, these approaches are reaching practical limits. Cognitive radio allows new approaches to improve the intensity of use in spectrum which is licensed but under utilized. This paper addresses two such possible approaches. Real time spectrum markets permit users to exchange spectrum use. Interruptible spectrum would allow public sector spectrum users to recoup economic benefits for allowing others to share their low average, high peak use spectrum subject to preemption.

Method of vegetation spectrum measurement using multi spectrum camera

  • Takafuji, Yoshifumi.;Kajiwara, Koji.;Honda, Yoshiaki.
    • Proceedings of the KSRS Conference
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    • pp.570-572
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    • 2003
  • In this paper, a method of vegetation spectrum measurement using multi spectrum camera was studied. Each pixel in taken images using multi spectrum camera have spectrum data, the relationship between spectrum data and distribution, structure, etc. are directly turned out. In other words, detailed spectrum data information of object including spatial distribution can be obtained from those images. However, the camera has some problems for applying field measurement and data analysis. In this study, those problems are solved.

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Simulations of Two-Dimensional Electronic Correlation Spectra

  • Kim, Hak Jin;Jeon, Seong Jun
    • Bulletin of the Korean Chemical Society
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    • v.22 no.8
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    • pp.807-815
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    • 2001
  • Two-dimensional (2D) correlation method, which generates the synchronous and the asynchronous 2D spectrum by complex cross correlation of the Fourier transformed spectra, is an analysis method for the changes of the sample spectrum induced by vari ous perturbations. In the present work, the 2D electronic correlation spectra have been simulated for the cases where the sample spectrum composed of two gaussian bands changes linearly. When only the band amplitudes of the sample spectrum change, the synchronous spectrum shows strong peaks at the band centers of the sample spectrum, but the asynchronous spectrum does not make peaks. When the sample spectrum shifts without changing intensity and width, the synchronous spectrum shows peaks around the initial and final positions of the band maximum and the asynchronous spectrum shows long peaks spanning the shifting range. The band width change produces the complex 2D correlation spectra. When the sample spectrum shifts with band broadening, the width change by 50% of full width at half maximum (FWHM) does not give so large an effect on the correlation spectrum as the spectral shift by one half of FWHM of the sample spectrum.

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Development of Simulated HPGe Detector Spectrum for Education (교육용 모사 HPGe 검출기 스펙트럼 개발)

  • Seo, Kyung-Won;Lee, Mo-Sung
    • Journal of Radiation Protection and Research
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    • v.32 no.1
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    • pp.9-13
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    • 2007
  • From HPGe calibration spectrum of liquid mixed source in cylindrical vial, we developed simulated spectrum for spectrum analysis education. It is the spectrum that combine peaks separated from measured spectrum. After that, spectrum removed statistical variation of channel counts. Statistical fluctuation of the spectrum is made by Box-Muller function. The spectrum contains 18 peaks. The peak's centroid and area were defined exactly. Developed spectra are calibration spectrum, sample spectrum, background spectrum and spectra for efficiency correction for geometry and cascade coincidence.

A Proactive Dynamic Spectrum Access Method against both Erroneous Spectrum Sensing and Asynchronous Inter-Channel Spectrum Sensing

  • Gu, Junrong;Jang, Sung-Jeen;Kim, Jae-Moung
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.6 no.1
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    • pp.361-378
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    • 2012
  • Most of the current frequency hopping (FH) based dynamic spectrum access (DSA) methods concern a reactive channel access scheme with synchronous inter-channel spectrum sensing, i.e., FH is reactively triggered by the primary user (PU)'s return reported by spectrum sensing, and the PU channel to be switched to is assumed precisely just sensed or ready to be sensed, as if the inter-channel spectrum sensing moments are synchronous. However, the inter-channel spectrum sensing moments are more likely to be asynchronous, which risks PU suffering more interference. Moreover, the spectrum sensing is usually erroneous, which renders the problem more complex. To address this problem, we propose a proactive FH based DSA method against both erroneous spectrum sensing and asynchronous inter-channel spectrum sensing (moments). We term it as proactive DSA. The optimal FH sequence is obtained by dynamic programming. The complexity is also analyzed. Finally, the simulation results confirm the effectiveness of the proposed method.

Analysis of Future Spectrum Sharing Ecosystem Based on Causal Map (인과지도에 기반한 미래 주파수공유 생태계 분석)

  • Song, Hee Seok;Kim, Taehan
    • Journal of Information Technology Applications and Management
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    • v.20 no.4
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    • pp.19-31
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    • 2013
  • There is tremendous increasing demand on spectrum resource which is boosted by spread of cloud computing and M2M telecommunication as well as smart phone and tablet PC. Recently, spectrum sharing technology has drawn attention to the spectrum policy makers as a promising way to overcome limitation of scarce spectrum resource. To succeed in commercialization of spectrum sharing technology, it is necessary to prospect the future business ecosystem of spectrum sharing and develop appropriate policies and laws at the same time along with the advance of spectrum sharing technology. The purpose of this paper is to prospect future spectrum sharing ecosystem and analyze business ecosystem of spectrum sharing with casual loop map. With the causal map and system dynamics method, it is possible to analyze feedback loops which is not limited to linear thinking and build policies which optimize positive dynamics in business ecosystem of spectrum sharing.

Deep Recurrent Neural Network for Multiple Time Slot Frequency Spectrum Predictions of Cognitive Radio

  • Tang, Zhi-ling;Li, Si-min
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.11 no.6
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    • pp.3029-3045
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    • 2017
  • The main processes of a cognitive radio system include spectrum sensing, spectrum decision, spectrum sharing, and spectrum conversion. Experimental results show that these stages introduce a time delay that affects the spectrum sensing accuracy, reducing its efficiency. To reduce the time delay, the frequency spectrum prediction was proposed to alleviate the burden on the spectrum sensing. In this paper, the deep recurrent neural network (DRNN) was proposed to predict the spectrum of multiple time slots, since the existing methods only predict the spectrum of one time slot. The continuous state of a channel is divided into a many time slots, forming a time series of the channel state. Since there are more hidden layers in the DRNN than in the RNN, the DRNN has fading memory in its bottom layer as well as in the past input. In addition, the extended Kalman filter was used to train the DRNN, which overcomes the problem of slow convergence and the vanishing gradient of the gradient descent method. The spectrum prediction based on the DRNN was verified with a WiFi signal, and the error of the prediction was analyzed. The simulation results proved that the multiple slot spectrum prediction improved the spectrum efficiency and reduced the energy consumption of spectrum sensing.

Spectrum-Band Prioritization Scheme for Establishing Efficient Spectrum-Use Policy (효율적 주파수 이용 정책 개발을 위한 주파수 대역 이용효율개선 우선순위 평가 방안)

  • Lee, Sang-Yun
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.30 no.6
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    • pp.452-466
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    • 2019
  • As the spectrum demand increases, securing spectrum resources in a timely manner becomes necessary. This paper proposes a spectrum-band prioritization scheme for establishing an efficient spectrum-use policy. The criteria for spectrum-band prioritization are derived from articles of the Radio Waves Act, and a four-level matrix for priority evaluation is proposed, considering both demand urgency and supply ease. The prioritization processes and items to consider for measuring each criteria are also proposed in order to implement the proposed prioritization scheme. It is expected that the proposed scheme can help secure the spectrum in a timely manner, protect incumbent users properly, and promote new spectrum-based businesses.