• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.1
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• pp.34-40
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• 2001

The necessary of research is proposed about sharing between networks of the fixed-satellite service using non-geostationary satellites and other networks of the fixed-satellite service, interference criteria and calculation methods for the fixed-satellite service because WRC-2000 make a decision that the frequency bands l1/14GHz and 20/30GHz are available to system in the fixed-satellite service employing satellite in both geostationary and non-geostationary orbits. In the paper, four methodologies attempting to derive continuous curves of korea satellite network EPFD(equivalent power flux density) are used.

• Journal of Satellite, Information and Communications
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• v.10 no.3
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• pp.137-142
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• 2015

This paper analyzed the background and status of studies for WRC-15 agenda item which considers additional frequency allocations to the fixed-satellite service in Ku-band and considered national future countermeasures. Satellite frequency can be acquired through compliance with the Radio Regulations for international registration and it has been recognized as the limited natural resource, and which leads to intensifying the competition among countries for the preoccupancy of it. Under the circumstances, WRC-15 is going to consider additional allocations to the fixed-satellite service in Ku-band and it is necessary to cope with the situation taking into account adequate protection of the existing services and future plan of frequency usage by the fixed-satellite service.

• Proceedings of the IEEK Conference
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• 2000.11a
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• pp.465-468
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• 2000

The interference situation for the satellite networks using non-geostationary satellite orbit (NGSO) is more complicated than the situation between geostationary satellite orbit (GSO) networks because of the time varying orbital characteristics of NGSO systems. Most of frequency bands are allocated to fixed-satellite service and liked-service in co-primary basis. In this paper, the sharing criteria between NGSO/FSS systems and HDFS (High Density Fixed-Service) are examined.

• Journal of Advanced Navigation Technology
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• v.21 no.5
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• pp.428-434
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• 2017

In recent years, owing to the growing user demand for the two-way internet service based on the mobile global broadband communications, a new type of satellite terminal has been developed, known as ESIM(Earth Station in Motion). This service was required by Resolution 158(WRC-15) to study on the coexistence with the co-primary FS(Fixed Service) in 27.5-29.5 GHz as a FSS(Fixed Satellite Service) uplink. In this paper, the average received power on ESIM within -10 dB of beam width of FS and its outage probability was analyzed theoretically and also simulated to account for the azimuth angle with uniform distribution. From the results, it can be concluded that this theoretical analysis is very useful to analyze the interference from ESIM into FS based on the statistical and probabilistic method. Therefore, it is necessary to control the azimuth angle due to a moving terminal as well as the inclination angle of moving path, the operation hours, and the speed of ESIM to protect the co-primary FS.

• Journal of information and communication convergence engineering
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• v.18 no.3
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• pp.155-161
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• 2020

The fifth generation (5G) is a state-of-the-art mobile communication access technology that uses sub 6 GHz bands and mmWave. Presently, the 5G network is partially deployed along with 4G in areas with dense traffic. In the future, the demand for the 5G bandwidth may increase. Thus, it is necessary to study the coexistence between the 5G and radio systems using adjacent or same channels to eliminate the interference between radio systems and efficiently utilize the frequency. This paper analyzed the impact of 5G new radio downlink on the fixed-satellite service earth station operating at the co-channel and adjacent channel in the upper 3.7 GHz band using the Spectrum Engineering Advanced Monte Carlo Analysis Tool, which is based on the Monte Carlo method. The results of this paper can be utilized for planning the frequency allocation of 5G networks; they can also be used as a guideline for deploying 5G base stations around a fixed-satellite service earth station.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.10 no.6
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• pp.273-286
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• 1985

Nowadays, the satellite communication systems provide worldwide or international service through organizations such as INTELSAT and INMARSAT, and the satellite communication technology has brought remarkable changes in the maritime mobile service as well as the fixed service on land. In our country, the international fixed satellite service via INTELSAT is no means inferior to the advanced countries, but to the contrary, we feel ashamed to admit that the facilities and technologies of our maritime satellite service via INMARSAT system donot keep abreast with the development pace of the world. This paper describes first the historical review of the development of satellite communication system is the world, then analyses the problems to bring the systems into wider use as early as possible, and filnally, I will make the following suggestions for the promotive direction on the INMARSAT systems. 1. Estabilishment of the earth stations at sea and on land. 2. Standardization of the qualification of the principal communicator on board. 3. Promotion of the international cooperation for the maritime mobile satellite service. 4. Establishment of the research institute on the INMARSAT systems.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.12
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• pp.1279-1286
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• 2009

This paper addresses the analysis of the interference produced between the LEO(Low Earth Orbit) satellite constellation and FS(Fixed Service) system operating in the same frequency and area. At first, we calculates the interference of FS system from the LEO satellite constellation depending on the number of LEO satellite antenna beams. Simulation results show that the amount of interference that was calculated from each region. This result can be used to define the carrier level for protecting FS system from total interference by LEO satellite constellation. In the second scenario, we calculates the interference of LEO satellite system earth station by the FS link depending on radius of protection area. The presented results can be used to design FS systems minimizing interference to earth station.

• Journal of Communications and Networks
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• v.9 no.2
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• pp.159-166
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• 2007

In this paper, we propose an efficient and robust interference mitigation technique based on a nullsteering multi-user multiple-input multiple-output (MU-MIMO) spatial division multiple access (SDMA) scheme for frequency sharing between IMT-advanced and fixed satellite service (FSS) in the 3400-4200 and 4500-4800 MHz bands. In the proposed scheme, the pre-existing precoding matrix for SDMA unitary precoded (UPC) MIMO proposed by the authors is modified to construct nulls in the spatial spectrum corresponding to the direction angles of the victim FSS earth station (ES). Furthermore, a numerical formula to calculate the power of the interference signal received at the FSS ES when IMT-Advanced base stations (BS) are operated with the interference mitigation technique is presented. This formula can be derived in closed form and is simply implemented with the help of simulation, resulting in significantly reduced time to obtain the solution. Finally, the frequency sharing results are analyzed in the co-channel and adjacent channel with respect to minimum separation distance and direction of FSS earth station (DOE). Simulation results indicate that the proposed mitigation scheme is highly efficient in terms of reducing the separation distance as well as robust against DOE estimation errors.

• Journal of Satellite, Information and Communications
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• v.4 no.2
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• pp.20-27
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• 2009

In this paper, HAPS operation scenario is proposed to minimize the interference from HAPS user terminal(HUT) to geostationary earth orbit(GEO) satellite receiver. The conventional scenario has been assumed for fully operated situation of HUT. However, all the HUTs could not be fully operated in a real system operation. Therefore, in order to reduce the interference to other systems, multibeam operation scenarios such as time division and adaptive time division methods are proposed and the interference effect of HUT to satellite receiver is evaluated according to various operation rate of HUT.

• Journal of Advanced Navigation Technology
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• v.23 no.6
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• pp.507-514
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• 2019

Federal communications commissions (FCC) has announced the first set of rules for 3.5 GHz (3,550 - 3,700 MHz) band used Navy radar and fixed satellite service (FSS) earth stations as primary service to sharing for citizen broadband radio service (CBRS) enable development of relatively low powered network technologies like small cells. Since CBRS sharing technique based on the 3-tiered spectrum access system (SAS) is able to protect the higher tiered users from harmful interference from lower tiered users, it has been considered actively to be introduced in Korea. However, 3.5 GHz band had been already allocated to the 5G services in Korea, the sharing studies have been carried out for 3,700 - 5,000 MHz, As the result, the 3.8 GHz (3,800 - 3,900 MHz) band used for only FSS system is able to be sharing, and an introduction of CBRS has been proposed in Korea by analyzing the interference to the FSS earth stations.