• Journal of Satellite, Information and Communications
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• v.6 no.1
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• pp.97-102
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• 2011

The Korean radio broadcasting system is analog. Digital Radio will transmit a digital signal to existing analog FM/AM. It provides clear sound quality, traffic information, weather information and various value-added services. In addition, the converted digital radio will be able to meet demand to growing demand for analog FM. DRM + is an area to place, depending on the frequency of usage to less interference can be placed anywhere. In this paper, DRM + system, a brief description, and is currently using the frequency status were described, accordingly DRM + candidate channel derived measures proposed, the existing analog broadcast and DRM + of interference effects through the simulation has been verified.

• Journal of Satellite, Information and Communications
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• v.10 no.4
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• pp.141-145
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• 2015

The dynamic range of the loudness after digitalization of television broadcasting is enlarged, and the loudness difference between the broadcast channel and between the programs within the same channel is expanded. This was subjected to interfere with the television viewer's comfort. In order to improve these problems international standards for the loudness normalization was established in ITU, Europe, USA and Japan. This regulation was introduced to Korea also as technical regulation, and this will apply the broadcast service in June 2016. In this paper, ahead of the introduction of digital television technology based on loudness measurement for the major television channel and to present the results of the comparison of technical standard.

• Journal of Astronomy and Space Sciences
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• v.27 no.3
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• pp.221-230
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• 2010

A 4+12+16 amplitude phase shift keying (APSK) modulation outperforms other 32-APSK modulations in a nonlinear additive white Gaussian noise (AWGN) channel because of its intrinsic robustness against AM/AM and AM/PM distortions caused by the nonlinear characteristics of a high-power amplifier. Thus, this modulation scheme has been adopted in the digital video broadcasting-satellite2 European standard. And it has been considered for high rate transmission of telemetry data on deep space communications in consultative committee for space data systems which provides a forum for discussion of common problems in the development and operation of space data systems. In this paper, we present an improved bits-to-symbol mapping scheme with a better bit error rate for a 4+12+16 APSK signal in a nonlinear AWGN channel and propose a simple signal detection algorithm for the 4+12+16 APSK from the presented bit mapping.

• Journal of Satellite, Information and Communications
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• v.12 no.1
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• pp.18-21
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• 2017

In this paper we present IoT compliant HD Digital Signage Controller design using Raspberry Pi. Nowadays, the digital signage system have gained increasing popularity and rapidly growing communications medium that offers a wide range of exciting ways with customers, enhance brand awareness, increase sales and margin uplift by replacing the traditional static signage system. This paper presents a cost-effective IoT based HD Digital Signage Controller (DSC) using R-Pi computer that can use various kinds of displays in order to make the system as efficient and affordable as possible to provide advertisement or other relevant information to people in public areas. The system is designed in such way the information about surrounding related place is taken through sensors and directly uploaded to the internet, and thus can be accessed anytime and displayed on screens by using Raspberry Pi that serves as controller in the system. The design and implementation of the system developed by using python programming language and its hardware consists of sensors, Arduino, Raspberry Pi 3 model B board and the displays. The main targets of this study are build a cost effective Digital Signage system as well as broadcasting information at display contents in public areas and control those digital signs.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.856-860
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• 2007

In this paper, we propose a microstrip antenna with sufficient impedance bandwidths and gains for the 2.65GHz antenna which used in the satellite digital multimedia broadcasting. The proposed 2.65GHz S-DMB bandwidth microstrip antenna on a substrate, which is small enough to be installed in practical mobile phones, and described simulation feature using by CST Microwave Studio program. The measured result is similar with commercial antenna and acceptable frequency band is found that more wide than the existing products.

• 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.

• Publications of The Korean Astronomical Society
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• v.19 no.1
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• pp.129-133
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• 2004

In the past, radio astronomers have sought isolation from man-made signals by placing their telescopes in remote locations. These measures may no longer safeguard scientific observations, since NGSO satellite systems, particularly low-Earth orbit (LEO) systems, are usually designed to provide global or wide regional coverage. Further, radio astronomers have historically made their observations in the frequency bands allocated for their use by the member countries of the International Telecommunication Union (ITU). The science of radio astronomy could be adversely impacted by the deployment of large constellations of new non-geostationary orbiting (NGSO) satellites for telecommunications, navigation and Earth observation, and the proliferation of new, high-power broadcasting and telecommunication satellites in geostationary (GSO) orbits. Radio telescopes are extremely sensitive, and, in certain situations, signals from satellites can overwhelm the signals from astronomical sources. This paper describes the problem in detail and identifies ways to mitigate it without adversely affecting the continued vigorous growth of commercial space-based telecommunications.

• Journal of Satellite, Information and Communications
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• v.11 no.2
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• pp.48-54
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• 2016

As the nonlinear viewing patterns are getting generalized, the needs for VOD service of consumers are increasing in TV, webTV. But today's VOD system is all automated, except the part for posting contents. This study proposes the method for automation of the content posting. For this we analyzed the broadcast program structures by genre in order to detect the transition point between the advertisement and the contents. It was found that regular black frames were set in the transition during fade in and out. We propose an efficient approach to automatically detect the black frames using RGB values of each frame that enable VOD content posting and replace an advertisement in VOD service.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.11B
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• pp.1618-1623
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• 2010

In this paper, we propose a new assisted global positioning system (A-GPS) using terrestrial digital multimedia broadcasting (T-DMB) data services. Because of the weak signal strength from GPS satellite and the signal blockage, it is difficult for the telematics terminal to determine the position in urban area. Proposed A-GPS system calculates pseudo range (PR) from timing information of GPS satellites and obtains the satellite information such as ephemeris from T-DMB station to determine the current position. Compared to conventional GPS system, the proposed system has better performance in terms of the fast time to first fix (TTFF), low horizontal dilution of precision (HDOP). Experimental results show that the proposed system is a feasible and robust solution.

• Proceedings of the IEEK Conference
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• 2002.07c
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• pp.2043-2046
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• 2002

This paper studies on Sun interference effects or Sun outage effects on C-band satellite reception signal for THAICOM2. The THAICOM2 satellite is at 78.5 degree East 〔co-located with THAICOM3〕. The down link station was located in Khon-kaen, longitude 102.83 degree East and latitude 16.43 degree North. The antenna diameter is 4.6 meters for C-band downlink station. Total 9 times of sun interference events were occurred during summer and fall of 2001 and these about 53 minutes altogether. The Maximum CM degradation of the THAICOM2 system was around 11 dB. The Sun interference events of 53 minutes of one year are 0.0122 percents of the C-band contact time when 21 hours of contact time is used f3r broadcasting a day.