• 한국ITS학회:학술대회논문집
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• 2008.11a
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• pp.132-136
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• 2008

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.07a
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• pp.225-225
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• 2004

• Journal of Advanced Navigation Technology
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• v.15 no.5
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• pp.839-844
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• 2011

Various technologies such as infrared light, ultrasonic waves, RFID, GPS, UWB, and signal indicators have been incorporated in the location tracking system. However, such pre-existing systems require location recognition in shadow areas. This study proposes a location tracking system that utilizes Cooperative Spectrum Sensing. Cooperative Spectrum Sensing is not only able to track the location and path of moving objects but also recognize when objects breakaway from the path set by sensors and guide them back. In addition, it has the advantage of being more efficient in terms of frequency usage. It is able to automatically fix power transmission and frequency modulation for transmission cognitive users to an optimum level within the range that does not cause interference for primary users.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.4
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• pp.853-871
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• 2012

The location based service is divided into GPS that uses the artificial satellite or base transceiver station in order to cover the wide area and RTLS(Real Time Location System) using the Zigbee, RFID, CSS(Chirp Spread Spectrum), UWB, Bluetooth and Wi-Fi equipment in the space(close range) limited like the building inside or park. Moreover it also repeats the technical development upon through the acceleration of the development of the wire and wireless infrastructure and determination technology, the development of the Internet, diversification of the contents, and etc. As a result, it is expected to develop around the determination technology, witch is common core technology element, contents technology, Internet and mobile communication technology, and etc. afterward. In this research, the direction we investigate was to find and analyze new technology and standardization trend of LBS in order to contribute to the related industry.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.9C
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• pp.905-913
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• 2006

In the impulse radio ultra-wideband communication systems, the residual timing offset exists when the acquisition and tracking of the timing synchronization is well done. And the offset affects the performance of the system dramatically. In order to compensate the offset, we present the digital phase-locked loop that uses the reference signal in the correlation detection receiver. First, we show the degradation of BER performance that is caused by the offset, and then compensation process of the timing tracker and performance improvement. In this paper, the timing detector in the tracker operates at the sampling period of frame level uses the correlation between received and reference signal. Also, we present the performance comparison by using the computer simulation results for different Gaussian monocycle pulses.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.3C
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• pp.127-132
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• 2011

In this paper, we propose a cooperative communication scheme for high transmission efficiency and coverage extension under multipath fading environment of moving networks. The proposed scheme uses a Space-Time Block Code (STBC) for improvement of receiving performance by using virtual Multiple-Input Multiple-Output(MIMO) transmit diversity. It can also achieve faster transmission time than a conventional scheme by using virtual MIMO configurations. Simulation results have shown that the proposed scheme provides SNR improvement and has faster transmission time compared to the conventional scheme, since it can utilize the good properties of spatial diversity and coding gain by using virtual MIMO configuration. In this paper, we propose simulations of UWB communication system to show validity by using the MATLAB.

• Journal of Ubiquitous Convergence Technology
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• v.2 no.1
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• pp.51-55
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• 2008

A digital home is a ubiquitous environment that is expected to be realized in the near future. All information appliances in a house are connected to each other through wired and/or wireless home networks. Authenticated user can access the various services provided by the digital home, and the access is not restricted by equipment, time, or location. The technologies that form the digital home can be grouped into two categories: wired networking technologies and wireless networking technologies. For the purpose of ubiquitous environments, wireless-networks offer suitable and seamless high-quality services. A wireless LAN can be created simply by equipping a single access point. For that reason, the cost of establishing such a network is low and using it is easy. Of course, there is an exciting new wireless technology. It is the Ultra Wide Band (UWB). However, it is not enough to bring wireless convenience, although offering a broad range of high-speed data transfer capabilities, Because of unstable. Thus, of the wireless-networking systems, we focus on the wireless LAN. We quantitatively analyze its capabilities. The dynamic and adaptive wireless LAN provides a foundation for the evolution toward the next generation of wireless and adaptive networks. The difference between wired LAN and wireless LAN in upload and download rates is small. Although the wireless LAN experiences a greater loss rate than the wired LAN, the difference is minimal. We conclude that a wireless LAN is suitable for use in an apartment environment.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.12
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• pp.12-19
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• 2014

In this paper, an advanced UWB (ultra wideband) Rake receiving technique based on the statistical distribution model is studied in the M-ary TH-PPM system with multiple access interference (MAI). In order to improve the performance of the Rake receiver, the stochastic model, which can flexibly express the behavior of MAI-plus-noise, is required and the Laplace distribution and the generalized normal Laplace (GNL) model applied by the curtosis matching method are considered. The performance of Rake receiver based on each probability distribution is evaluated in the IEEE multipath fading channel and compared to that of the conventional Rake receiver. The suggested approach shows a superior BER performance than that of conventional Rake receiver.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.7
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• pp.1524-1532
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• 2012

The calibration method using the existing environmental characteristics is to correct taking advantage of the data that is followed Judgement on the environment. If a decision is not made on the environmental judgement, the use of traditional methods may increase rather than errors. In this paper, UWB-based localization system is utilized. We propose Location Correction Algorithm which is available on if you can not make a judgment about any circumstances for location estimation system. Reference Points was selected to observe the characteristics of the localization system. This paper searched the characteristics of the localization system in LOS environment and NLOS environment, and used data correcting the location information of the moving object by combining the two environmental characteristics. The Location Correction Algorithm is applied to the location measured from the location estimation system. This algorithm corrects for the location information of the object. As a result, the location accuracy improvement were observed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.12C
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• pp.1606-1616
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• 2004

This paper introduces a technique for generating an appropriate template signal via modeling of minimum-phase stable ARMA (Auto-Regressive Moving Average) system for coherent impulse communication systems. It has been well known that the transmitted impulse signal becomes deformed because of dispersive and resonant characteristics. Accordingly, in spite of using ideal template signal at the correlator, these impairments degrade overall performance attributed to low level of coherence. To increase the degree of coherence, our proposed scheme realizes A3U system derived by Gaussian pulse signal, which simulates the overall characteristic of transfer function in between transmit and receive wideband antennas so as to generate an appropriate template signal in a form of output. The performance of proposed scheme will be shown in results from computer simulations to verify its affirmative impact on impulse communication system with regarding several distinctively shaped antennas.