• ETRI Journal
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• v.25 no.4
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• pp.211-218
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• 2003

This paper presents a dynamic resource allocation algorithm with multi-frequency time-division multiple access for the return link of interactive satellite multimedia networks such as digital video broadcasting return channel via satellite systems. The proposed timeslot assignment algorithm, called the very efficient dynamic timeslot assignment (VEDTA) algorithm, gives an optimal assignment plan within a very short period. The optimality and computational efficiency of this algorithm demonstrate that it will be useful in field applications.

• Journal of Satellite, Information and Communications
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• v.6 no.2
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• pp.35-40
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• 2011

The purpose of this study is to know about the interference on FM Radio channel from DRM+ signal. In Korea, a data service channel, named DARC is operated by a major FM radio broadcaster which has national wide service area. Therefore, an analysis of the interference on FM radio channel with DARC data channel from DRM+, most recently developed digital radio system. Technical parameters of FM radio with DARC data channel and DRM+ system are considered for this simulation. To maintain without no interference from DRM+, FM radio channel with DARC data channel should have the power level difference over 14.7dB at 150KHz frequency distance.

• Journal of the Korea Society of Computer and Information
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• v.24 no.7
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• pp.71-78
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• 2019

This paper describes a design for a RF receiver to receive satellite digital audio service. The RF receiver designed in this study is a planar structure that is easy to install on the rooftop of a car and is compact in size. In addition, it can be applied to certain commercial models because it has low noise and high gain characteristics. The impedance bandwidth of antenna is 17.8%(415MHz), and the axial ratio is below 3dB as good properties for the bandwidth of 40MHz which is a satellite digital audio service band. Also, it had a broad radiation beamwidth of $95.41^{\circ}$ in H-plane and $117.45^{\circ}$ in E-plane. From the results of the field test of satellite digital audio service reception for the RF receiver, it demonstrated good C/N rate(10.2dB).

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2003.05a
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• pp.744-748
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• 2003

Developing an interactive satellite multi­media system, such as a digital video broadcasting (DVB) return channel via satellite (RCS) system, is gaining popularity over the world To accommodate the increasing traffic demand we are motivated to investigate an alternative for improving return channel utilization We develop an efficient method for optimal packet scheduling in an interactive satellite multimedia system using hybrid CDMA/TDMA channels. We formulate the timeslot-code assignment problem as a binary integer programming (BIP) problem, where the throughput maximization is the objective, and decompose this BIP problem into two sub-problems for the purpose of solution efficiency. With this decomposition, we promote the computational efficiency in finding the optimal solution of the original BIP problem Since 2001, ETRI has been involved in a development project where we have successfully completed an initial system integration test on broadband mobile Internet access via Ku-band channels using the proposed resource allocation algorithm.

• ETRI Journal
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• v.24 no.3
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• pp.251-254
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• 2002

We developed a method for optimal superframe design in the multi-frequency time division multiple access (MF-TDMA) return-link of a satellite multimedia interactive network called a digital video broadcasting return channel over satellite (DVB-RCS) sub-network. To find the optimal superframe pattern with the maximum data throughput, we formulated the design problem as a non-linear combinatorial optimization problem. We also devised the proposed simple method so that it would have field applicability for improving radio resource utilization in the MF-TDMA return link.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.151-154
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• 1998

The interference evaluation methods and criteria between the analogue TV/FM signals for BSS(Broadcasting Satellite Service) plans and the associated feeder link plans were established in WARC(World Administrative Radio Conference)-77 and 88. However, it should be applied the different interference evaluation methods and criteria of the digital TV signals from those of the analogue TV/FM signals. In this paper, the interference evaluation methods and criteria between the digital TV signals and the analogue TV/FM signals were analyzed. And also, the effects of the interference from the digital signals for Koreasat-1 into the analogue TV/FM signals for Japanese broadcasting satellite were evaluated. The amounts of EIRP reduction in the transmitting space stations were calculated to meet the interference criteria. The results showed that the digital BSS networks including Koreasat-1 would share the limited resources with the analogue BSS networks.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.183-184
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• 2008

From the beginning of a new millennium, the digital broadcasting services had been adopted to cable, satellite and radio broadcasting services as well as the terrestrial TV broadcasting services. The government established the installation standard of digital receiving equipment in 2007, which is needed for taking the new digital broadcasting services without additional facilities in an apartment house. In this paper, I will show the installation standard of digital receiving equipment in an apartment house and give a detailed explanation for the main criteria of it.

• Journal of Communications and Networks
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• v.12 no.6
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• pp.558-567
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• 2010

In this paper, we analyze the capability of satellite broadcasting systems to offer different levels of quality of service (QoS). We focus on the European telecommunications standards institute satellite digital radio and digital video broadcasting satellite handheld (DVB-SH) standards, which have recently been proposed for satellite broadcasting communications. We propose a strategy to provide different levels of QoS for the DVB-SH standard on the basis of an extension of the interleaving scheme, referred to as molded interleaver, which supports low latency service requirements for interactive services. An extensive analysis based on laboratory measurements shows the benefits of this solution. We also present a multilevel coding (MLC) scheme with multistage decoding designed for broadcasting communications as an alternative to the existing standards, where services with different levels of QoS are provided. We present a graphical method based on mutual information for the design and evaluation of MLC systems used for broadcasting communications. Extensive simulations for a typical satellite channel show the viability of the proposed MLC scheme. Finally, we introduce multidimensional constellations in the proposed MLC scheme in order to increase the number of different protection levels.

• Journal of the Korean Geophysical Society
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• v.9 no.4
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• pp.387-395
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• 2006

Nowadays, various digital maps on a reduced scale were drawn in Korea including the topographic series of a nation. Though these digital maps are drawn and revised by using aerial photograph or satellite image, there are some problems that it is difficult to revise or renew the topography and natural feature immediately which changes frequently. As the countermeasures of these problems we use GPS accumbency method, which provides user with convenience and accumbency accuracy which is required to revise and renew digital maps. But acquiring correct position by using GPS only may cause not a few errors because of environmental effect of satellite signal errors that GPS obtains. Although accumulated errors which is the major problem of existing method was diminished owing to the position signal received from satellite which is about 20,183km above, the area that can not receives the signal is occur such as woods and high-rise buildings space. And because of the GDOP (Geometry Dilution of Precision) of GPS satellite and the periodically changing orbit of the satellite, the position calculating problems occur. For settlement of these problems and accurate position determination, DGPS (Differential GPS) is indispensably needed. So, in this study, by adapting Radio Beacon Receiver for marine position determination which is the most convenience method of DGPS methods, we elevated accuracy of modification and renewal of digital map and, having wide application in various measurements, proposed the rapid measurement method about widespread area. In this study, wewant to propose the work scheme of rapid modification and renewal of digital map by using Beacon GPS which is comparatively cheap of all the DGPS methods and which makes it possible to measure independently.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.746-749
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• 2002

This paper is introducing a radio control helicopter as a new platform of ground truth measurement. This helicopter is normally used for spraying an agricultural chemical. It can do pinpoint hovering and programing flight using DGPS etc., A spectrometer with dual port can measure ground surface and white reference plate at the same time. And it can also take digital images by digital camera. It is needed to collect ground reflectance information as satellite sensor footprint size for satellite data validation. Generally it is possible to get such ground reflectance by an airplane measurement. But it is high cost and not so easy to make a measurement by airplane. Developed validation system can provide such ground reflectance in low cost and easy.