• Journal of Communications and Networks
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• v.12 no.6
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• pp.582-591
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• 2010

Probabilistic modeling and analysis of correlation metrics have been receiving considerable interest for a long period of time because they can be used to evaluate the performance of communication receivers, including satellite broadcasting receivers. Although differential correlators have a simple structure and practical importance over channels with severe frequency offsets, closedform expressions for the output distribution of differential correlators do not exist. In this paper, we present detection error probability expressions for frame synchronization using differential correlation, and demonstrate their accuracy over channel parameters of practical interest. The derived formulas are presented in terms of the Marcum Q-function, and do not involve numerical integration, unlike the formulas derived in some previous studies. We first determine the distributions and error probabilities for single-span differential correlation metric, and then extend the result to multispan differential correlation metric with certain approximations. The results can be used for the performance analysis of various detection strategies that utilize the differential correlation structure.

• Proceedings of the KIEE Conference
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• 2007.04a
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• pp.289-291
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• 2007

The Digital Multimedia Broadcasting(DMB) system is developed to offer high quality audio-visual multimedia contents to the uses by the various portable terminals in the mobile environment. Integrated complex reception platform is required to receive multimedia broadcasting services transmitted from various transmission media. In this paper, we present the design and implementation technic for providing the both of terrestrial and satellite DMB services simultaneously using the same hardware platform. The implemented complex receiving terminal to accommodate these DMB services simultaneously need composed of it RF module. it baseband module, it complex control module and the complex de-multiplexer module. The complex control module is designed using uClinux operating system. The complex de-multiplexer, which perform the functions of the address decoder and each DMB stream de-multiplexer, is implemented. with FPGA device. The implemented platform is tested in a real environment and its performance is satisfied with required performance criteria.

• Journal of Satellite, Information and Communications
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• v.8 no.1
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• pp.45-53
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• 2013

An electrostatic discharge (ESD) protection device, so called, N-type extended drain silicon controlled rectifier (NEDSCR) device, was analyzed for high voltage I/O applications. A conventional NEDSCR device shows typical SCR-like characteristics with extremely low snapback holding voltage. This may cause latch-up problem during normal operation. However, a modified NEDSCR device with proper junction/channel engineering using counter pocket source (CPS) ion implantation demonstrates itself with both the excellent ESD protection performance and the high latch-up immunity. Since the CPS implant technique does not change avalanche breakdown voltage, this methodology does not reduce available operation voltage and is applicable regardless of the operation voltage.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.10
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• pp.34-41
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• 1998

In this paper, we evaluate synchronization techniques suitable for high-speed ATM satellite communications with a transmission rate of 155Mbit/s, and propose optimal algorithms that improve the tracking performance, where QPSK is selected for a modulation scheme, and the receiver is operated in burst mode. Based on these asumptions, we proposed modified algorithms and architectures for automatic frequency control(AFC), carrier recovery(CR), and symbol timing recovery(STR) for burst acquisition. Analysis is performed under AWGN environments with respect to the number of required symbol, steady-state stability, and hardware implementation for the proposed algorithms.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.2
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• pp.267-272
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• 2017

In this paper, we suggested that a RF-front module of down-converter that represents the lowest noise figure to receive high quality video signals because the attenuation occurs in the atmosphere over 20GHz. By budget analysis of CDR, SFDR and CIP3 of RF-FEM, we also analyzed the parameters and linearity that presents high dynamic range. The total gain of designed Ka-band down-converter is 61.8dBand noise figure is 1.05dB, so gain and noise figures show excellent properties. In the future, the designed RF-FEM will be applied to the Ka-band satellite down-converter for UHD-class video transmission.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2016.11a
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• pp.63-65
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• 2016

DVB (Digital Video Broadcasting)-S2 (Satellite - Second Generation) 표준은 현재 위성방송 시스템으로 가장 많이 사용되고 있는 표준이나, 추가적인 성능향상과 보다 다양한 응용분야에 적용하기 위해 DVB-S2 기술을 확장한 DVB-S2x (Satellite - Second Generation Extension) 시스템이 제정되었다. 그 중에서도 612,540 심볼 길이의 수퍼프레임 (Super-frame) 구조를 선택적으로 도입하여 긴 데이터 길이에 대해 스크렘블링 (Scrambling)을 적용하는 방법과 PLS (Physical Layer Signaling) 코드와 같은 참조 데이터 필드를 반복적으로 사용하는 방법 등을 사용할 수 있도록 하였다. 이를 통해 동일채널 간섭 (co-channel interference)에 대한 강인성을 증가시키고, 매우 낮은 SNR (Signal to Noise Ratio) 환경에서의 수신기 성능 향상 효과를 제공하게 된다 본 논문에서는 버스트 슈퍼프레임 전송 기반의 DVB-S2x 수신기를 위한 동기부를 설계하고 구조를 제안한다. 슈퍼프레임의 포맷은 DVB-S2x Annex E 의 규격 중 2 번 포맷을 이용하였으며, 2 번 슈퍼프레임 포맷은 버스트 (burst) 기반의 전송 방식에 용이한 측면이 있다. 동기부는 크게 버스트 검출부, 주파수 복구부, 신호 이득 조절부 그리고 심벌 타이밍 복구부로 구성된다.

• Korean Journal of Geomatics
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• v.4 no.2
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• pp.59-65
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• 2004

Recently, a lot of interest focuses on DGPS with which it is possible to obtain 3D geographic information in real time. There are some methods to transmit corrected signals which use ground based systems as beacon, as well as wireless and TV broadcasting media. However, these methods require a large number of stations. Therefore, when the distance from station to user is increased, there is a range limit to the transmission of corrected signals. In order to solve these problems, WADGPS method using Geo-satellite is being investigated. In this study, static and kinematic tests were performed by using Satloc SLX WADGPS and Ashtech receivers. The results showed that SA was affected most among corrected signals of WADGPS; it was followed by ionospheric delay, tropospheric delay and satellite orbit errors. The accuracy of static observation was approx. $\pm$1m on SA-on. This was ten times as accurate as that of absolute observation by common receiver on SA-off. In the SA-off, the accuracy of WADGPS can be improved further. The result of kinematic tests by WADGPS acted in concert with that of standard DGPS by C/A code. It was concluded that the application of W ADGPS could improve considerably navigation and the construction of geographic information.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.9A
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• pp.1306-1312
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• 2000

The quality loss of a X-band transmitter has been derived by means of MC simulation. The transmitter as a payload of LEO(Low Earth Orbit) satellite is capable of the down transmission the image data of hundreds Mbps generated from the Electro-Optical Instrument in real time. The parameters such as data asymmetry amplitude unbalance,phase unbalance, wave shaping and channel interference are included in the quality loss simulation Assuming that normally distributed gaussian noise is simply added to the channel, the quality loss of 0.7 dB has been obtained through this simulation based on a 95% confidence interval. The obtained quality loss can be applied to the link budgets as an additional loss item.

• Journal of Satellite, Information and Communications
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• v.7 no.1
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• pp.21-26
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• 2012

For the last 20 years, our country has been pointing to a great power for digital information technology, but quantum information technology which is already researched in many forefront nations lags significantly behind other countries. Recently, quantum information management, quantum computing and quantum communication based on the quantum mechanics have been researching actively in many fields such as cryptology. On the basis of these background, in this paper, to efficient data transmission and detection for quantum data, we apply the orthogonal sequence to quantum communication system. The performance of proposed scheme is analyzed in terms of auto and cross correlation performance.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.2
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• pp.97-102
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• 2019

The GNSS(Global Navigation Satellite System) provides important information such as Position and Navigation, Timing(PNT) to various weapon systems in the military. as a result, applications that employ satellite navigation systems are increasing. therefore, a number of studies have been conducted to deceive the weapon systems that employ GNSS. GNSS spoofing denotes the transmission of counterfeit GNSS-like signals with the intention to produce a false position and time within the victim receiver. In order to deceive the victim receiver, spoofing signal should be synchronized with GNSS signal in doppler frequency and code phase, etc. In this paper, Civilian GPS L1 C/A spoofing signals have been evaluated and analyzed by SDR receiver.