• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.3A
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• pp.296-303
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• 2008

Co-existence of various wireless systems may cause frequency interference problem. For this reason, frequency sharing studies play a very important role in order to use limited spectrum resources efficiently. Especially, because a satellite system covers a global area in nature, the frequency sharing between the satellite system and terrestrial systems is essential. For satellite systems using Ka bands, we can increase spectrum efficiency by considering off-axis angles of earth station antenna. In this paper, we demonstrate the analysis result of separation distance between the satellite earth station and a terrestrial repeater, and the presented results can be used to design and implement Ka band wireless systems.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.4
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• pp.366-374
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• 2009

ITU has considered the 3,400$\sim$4,200 MHz band, which is allocated worldwide on a primary basis to the FSS, as a candidate band for future development of IMT system. In this band, this paper presents the results of the sharing studies performed between FSS and IMT systems through the theoretical and simulation analysis on the interference from multiple IMT base stations into a receiving FSS earth station considering the interference mitigation techniques such as antenna tilt angle and 3 sectors on the IMT base station. By using the long-term and short-term interference threshold, the coordination areas for the FSS earth station are provided to share frequency in 3,400$\sim$4,200 MHz band between FSS earth station and multiple IMT base stations in future.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.4
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• pp.805-814
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• 2013

According to the shut-down of Analog TV service on 30th. December, 2012, UHF Digital Dividend Band (698~806MHz) could be used for Mobile service such as LTE(Long Term Evolution). In the condition that this band is allocated for LTE service, Interference evaluation between LTE and adjacent DTV service was carried out, using LTE-A system-level simulator which was developed for simulation of IMT-Advanced technology. If LTE service be commercialized in this band, this study proposes the coexistence condition through the interference evaluation such as the effects not only to DTV receiver from LTE terminal but also to LTE base station from DTV transmitter. It is expected that the coexistence condition by these studies will be applied to network algorism for IMT-Advanced system in this band.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.10a
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• pp.247-252
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• 2000

In this paper, we discuss frequency allocation and sharing for high speed radio access network in domestic 5㎓ the band. In order to evaluate the possibility of frequency sharing between meterological radar and high speed radio access network we analyses radio interference of meterological radar by means of minimum coupling loss method and Monte Carlo simulation And simulations show that it is necessary to use DFS(Dynamic Frequency Selection) scheme for frequency sharing between meterological radar and high speed radio access network.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.4
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• pp.751-758
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• 2000

In this paper, we discuss frequency allocation and sharing for high speed radio access network in domestic 5GHz the band. In order to evaluate the possibility of frequency sharing between meteorological radar and high speed radio access network, we analyses radio interference of meteorological radar by means of minimum coupling loss method and Monte Carlo simulation. And simulations show that it is necessary to use DFS(Dynamic Frequency Selection) scheme for frequency sharing between meteorological radar and high speed radio access network.

• Journal of Advanced Navigation Technology
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• v.10 no.4
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• pp.312-318
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• 2006

WRC-2000 allowed HAPS to provide IMT-2000 service in the bands 1885-1980 MHz, 2010-2025 MHz and 2110-2170 MHz which have been utilized by the conventional terrestrial IMT-2000 service. In this paper, we analyze the interference effects from HAPS into terrestrial IMT-2000 system in adjacent band. To do this, in this paper, we have analyzed the interference and the sharing criteria between HAPS and the conventional terrestrial/satellite mobile system by considering the service and system requirements, the specification of system and developing the interference scenarios and the analysis algorithms.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2008.04a
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• pp.351-354
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• 2008

유비쿼터스 네트워크의 실현을 위하여 다양한 연구가 진행되면, CR (Cognitive Radio) 구성의 연구는 주파수 자원의 효율적인 활용에 관한 연구를 부각시키고 있다. 또한, CR 적용형 소출력 무선기기의 활용에 따른 공유주파수대역의 소요대역폭에 대한 논의와 공통으로 사용하는 주파수 대역 내에서 혼용되는 통신기기들의 user 수를 만족하는 총 소요대역폭 산출은 더불어 중요한 작업이 되었다. 공통으로 사용하는 주파수 대역의 총 소요대역폭 산출은 소출력 무선기기의 간섭 회피 기술로 사용되는 Frequency Hopping (FH) 및 Listen Before Talk (LBT) 방식이 고려되어야 한다. 본 논문에서는 Cognitive Radio (CR) 기반의 LBT 방식을 사용하는 ZigBee와 FH 방식을 사용하는 DCP, RFID, Bluetooth 등의 소출력 무선기기가 공통으로 사용하는 주파수 대역에 공존할 경우를 가정하고, 대기행렬이론 (Queuing Theory)을 적용하여 소요대역폭 산출을 수행했다. 채널수 별 user의 통신시도에 따른 throughput을 분석한 결과, throughput 84% 이상의 조건에서 FH 및 LBT 방식을 사용하는 250mW 소출력 무선기기들이 공존하는 공유주파수대역의 적정 채널수는 35개를 가지며, 총 소요대역폭은 채널수와 채널대역폭의 곱으로 산출이 가능함을 보였다. 이러한 접근방법은 다른 통신시스템의 소요대역폭 산출에도 유용할 것이다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.10a
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• pp.610-614
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• 2003

The bands 27.5 - 28.35GHz and 31.0 - 31.3GHz were allocated to the High Altitude Platform Station in WRC-2000. However, since these bands were already allocated to the existing fired-satellite service, the analysis on the interference effects between the existing FSS/GSO system and FS/HAPS system should be needed. To do study on the interference effects between above two systems, we can consider two frequency operational renditions, one is the Reverse mode and the other Forward mode. In this paper, we considered the Forward mode as the frequency operational condition and analyzed the interference effect from a number of GSO satellites to HAPS ground station due to the I/N values, the latitude of HAPS and the satellite separation. In future, these results will be vital data to share between HAPS and GSO systems.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.2A
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• pp.181-186
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• 2004

Analysis on sharing between GSO FSS and terrestrial system in the 40㎓ band, related with the problem for sharing between terrestrial services and FSS and identification of HDFSS downlink bands in World Radiocommunication Conference 2003, was practiced by assuming that both systems are operated in Korea. According to results from simulation using the characteristic parameters of GSO FSS and terrestrial FS system in 40 ㎓ described in ITU-R Recommendations, in case that elevation and azimuth angle of antenna of FS station are adjusted to point directly to the geostationary satellite, the GSO system can cause the worst interference to the FS system. This situation is possible to occur in the installation of 40 GHz FS station in urban area where there are high-rise buildings. If high-density FS stations in 40 ㎓ band are operated in the future, interference mitigation techniques to avoid GSO arc should be considered.

• Journal of Korea Multimedia Society
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• v.15 no.7
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• pp.903-909
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• 2012

In this paper, we analyze the sharing performances for coexistence of different communication systems between adjacent channels in TV White space. We analyze the parameter performance result according to various density of interfering transmitter and transmitter output. Two cases are analyzed to consider an interference effect between each system. First, WiBro is an interfering transmitter and WLAN is a victim receiver. Second, WLAN is an interfering transmitter and WiBro is a victim receiver. Free space channel model, Extended Hata and IEEE 802.11 model are used for channel environment. Analyzed coexistence results under various co-use scenarios may be widely applied into the technique developed to get the coexisting condition for wireless devices using many communication protocols in adjacent frequency.