• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.5
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• pp.745-758
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• 2022

As the unlimited natural source of a country, radio waves are widely being used in the daily life toward knowledge based information society. Therefore it is necessary to provide a long term policy of radio waves management policies based on market situation to cope with rapidly changing wireless technology and effective use of radio resources. Literary survey and analysis were accomplished for the rules and regulations in the radio station approval system and post-approval policies for mobile communication service. In conclusion, this study propose an blanket radio approval policy as well as self declaration of conformity(SDoC) of radio waves technical regulation and advanced radio inspection procedure. This study has significance in providing reference for introducing deregulation policy in the radio communication imdustry.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.4A
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• pp.373-378
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• 2007

In this paper, the Game Theory based power control for OFDM system is studied, which has attained intensive interest as a core artificial intelligent technology for Cognitive Radio and its efficiency is evaluated using performance metrics such as system throughput and fairness. Utility Function for joint user centric and network centric power control is defined and simulation results show that game theory based power control is far better than closed loop power control. The contribution of this paper is to formalize the game theory based power control toward the Cognitive Radio that recognizes and adapts to the radio communication environments.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.5
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• pp.1881-1903
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• 2015

With the fast-developing of mobile terminals, positioning techniques based on fingerprinting method draws attention from many researchers even world famous companies. To conquer some shortcomings of the existing fingerprinting systems and further improve its performance, we propose a radio map building and updating technique, which is able to customize the spatial and temporal dependency of radio maps. The method includes indoor propagation and penetration modeling and the analysis of human traffic. Based on the combination of Ray-Tracing Algorithm, Finite-Different Time-Domain and Rough Set Theory, the approach of indoor propagation modeling accurately represents the spatial dependency of the radio map. In terms of temporal dependency, we specifically study the factor of moving people in the interest area. With measurement and statistics, the factor of human traffic is introduced as the temporal updating component. We improve our existing indoor positioning system with the proposed building and updating method, and compare the localization accuracy. The results show that the enhanced system can conquer the influence caused by moving people, and maintain the confidence probability stable during week, which enhance the actual availability and robustness of fingerprinting-based indoor positioning system.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.6
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• pp.553-560
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• 2016

There propagate use management paradigm in developed countries is changing as Command & Control $\Rightarrow$ Market Based $\Rightarrow$ Open Access $\Rightarrow$ Manage By Technology & Technical Analysis, that the policy response to environmental changes, such as a variety of new technologies. The emergence of service, the proliferation of propagation users It is to activate the market. However, the basic principles of radio management such that the change of paradigm be used to spread in a range that does not affect the interference, such as the horn is to be observed. Around the world in order to prevent the propagation and utilization Horn interference enacted regulations for managing the radio station, and also discipline.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.12 no.1
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• pp.58-71
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• 2019

This paper proposes architecture of a cognitive radio engine platform and the allowable frequency channel reasoning method that enables acquisition of the allowable channels for the military tactical network environment. The current military tactical wireless communication system is increasing need to secure a supplementary radio frequency to ensure that multiple wireless networks for different military wireless devices coexist, so that tactical wireless communication between the same or different systems can be operated effectively. This paper presents the allowable frequency channel reasoning method based on cognitive radio engine for realizing DSA(Dynamic Spectrum Access) as an optimal available frequency channel. To this end, a case-based allowable frequency channel reasoning method for cognitive radio devices is proposed through modeling of primary user's traffic status and calculation of channel occupancy probability. Also through the simulation of the performance analysis, changing rate of collision probability between the primary users' occupancy channel and the available channel acquisition information that can be used by the cognitive radio device was analysed.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.6
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• pp.1479-1495
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• 2012

Spectrum scarcity seems to be the most challenging issue to be solved in new wireless telecommunication services. It is shown that spectrum unavailability is mainly due to spectrum inefficient utilization and inappropriate physical layer execution rather than spectrum shortage. Daily increasing demand for new wireless services with higher data rate and QoS level makes the upgrade of the physical layer modulation techniques inevitable. Orthogonal Frequency Division Multiple Access (OFDMA) which utilizes multicarrier modulation to provide higher data rates with the capability of flexible resource allocation, although has widely been used in current wireless systems and standards, seems not to be the best candidate for cognitive radio systems. Filter Bank based Multi-Carrier (FBMC) is an evolutionary scheme with some advantages over the widely-used OFDM multicarrier technique. In this paper, we focus on the total throughput improvement of a cognitive radio network using FBMC modulation. Along with this modulation scheme, we propose a novel uplink radio resource allocation algorithm in which fairness issue is also considered. Moreover, the average throughput of the proposed FBMC based cognitive radio is compared to a conventional OFDM system in order to illustrate the efficiency of using FBMC in future cognitive radio systems. Simulation results show that in comparison with the state of the art two algorithms (namely, Shaat and Wang) our proposed algorithm achieves higher throughputs and a better fairness for cognitive radio applications.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.8B
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• pp.910-920
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• 2011

In a heterogeneous wireless environment, a variety of Radio Access Technologies (RATs) coexist. Since the number of RATs is anticipated to increase in the near future, it is desirable to have radio and network resources managed in a cooperative manner using the Common Radio Resource Management (CRRM) strategy. In order to make RAT-specific radio resources manageable in CRRM, this paper proposes the Analytical Network Process (ANP) based resource management scheme that efficiently allocates resources among heterogeneous wireless networks. The proposed ANP-based method is flexible enough to be used in any network environment and can consider a multitude of decision factors. In addition, the proposed scheme uses a radio bandwidth model, which properly reflects transmission rates under given channel conditions, as the actual radio resources to be allocated. The model considers the AMC (Adaptive Modulation and Coding) scheme that is widely used in current broadband wireless access technologies, and thus, packet service characteristics, such as response time, can be analyzed. The effectiveness and flexibility of the proposed method are demonstrated by implementing a number of existing factors on heterogeneous networks environment.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.11
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• pp.2014-2020
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• 2016

In general, automatic access control management system using smart door-lock must be always exposed to security vulnerability during wireless communication based on Bluetooth. In particular, important information such as a secrete key can be exposed to the attacker when the authentication protocol has been operating in the wireless section. Therefore important information exchanged in the radio section needs to be properly encrypted. In order to analyze security vulnerability for automatic access control management system of public facilities such as subway vent, GNU Radio platform and HackRF device will be considered and experimented. Proposed experimental system to perform software based power analysis attack could be very effectively applied. As a result, important information such as packet type, CRC, length of data, and data value can be easily decoded from wireless packet obtained from HackRF device on GNU Radio platform. Constructed experimental system will be applied to avoid some security problems.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.12
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• pp.953-962
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• 2018

Recently, the Ministry of Internal Affairs and Communications of Japan has reported on a plan for the "effective use of radio waves" to be promoted in the 2020s. This includes promotion of the effective use of public frequencies, reviews of frequency allocation and transition systems, and spectrum usage fee system. Based on the proposals in this study, concrete systems for revising related laws, such as the Radio Law, will be designed and implemented. In addition, the government will jointly conduct research and development as well as verification tests in cooperation with industry, academia, and government. A plan to improve the system for the effective use of radio waves will then be devised. This study examines the policy directions of the frequency utilization system that Japan plans to use for radio waves in the 2020s. The policy directions are analyzed selectively while considering the radio waves utilization system in Korea, and implications for domestic applications are derived. Based on the research from this study, analyzing the radio policies of advanced countries, including those of England and the United States, and utilizing them to establish an effective use plan of radio waves in Korea are deemed necessary.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.7 no.2
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• pp.81-91
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• 2008

In mobile wireless communications, there is a new approach that uses the lacking spectrum efficiently. A cognitive radio is a device that can changes its transmitter parameters based on interaction with the environment in which it operates. At present, the wireless communication standard for wireless device contains power-saving modes or energy efficient mechanisms which cuts off the power of transmitter and receiver for power-saving. However, in cognitive radio environment, every device has the Quiet Period for searching channel and existing energy-saving method is not appropriate to be adjust to cognitive radio environment. In this paper, we propose an energy-efficient MAC protocol of mobile device in cognitive radio environment and prove the improvement of proposed method.