• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.11
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• pp.955-965
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• 2013

The joint tactical information distribution system (JTIDS) is used as the communication terminal of Link-16 by the United States armed forces, north atlantic treaty organization (NATO), and other allied forces. A portion of Link-16 frequencies may be shortly remapped to other systems owing to the growing demand for frequencies, especially in civil aviation, which is witnessing a constant increase in air traffic. This will affect the performance of Link-16. Therefore, in this paper, we analyze the effect of frequency band reduction on the performance of Link-16 waveform under partial-band noise jamming with Nakagami fading, via simulation and numerical analysis. The multi-net and anti-jamming performance of Link-16 with frequency remapping is compared with that of conventional Link-16 systems. The results show that the performance of Link-16 waveform is degraded with the reduction in frequencies. Nonetheless, Link-16 retains its jam resistance, and it can support multiple users in the same time slots.

• Journal of Digital Convergence
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• v.12 no.12
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• pp.37-47
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• 2014

The characteristics of the spectrum, which are necessary for mobile telecommunication services, may determine the advantage of operators' competition for mobile services. We have a focus on the possibility that there would be the core spectrum within the frequencies. We define the core spectrum of frequencies in terms of 4 criteria (global source/roaming, cost-effectiveness, the experience of utilization and the possibility of use). They are based on the aspects of applicative and economic effectiveness by not technological and but market conditions. We have explored the current core spectrum by using the stepwise selection from these criteria. Our result indicates that the core spectrum may be movable with the development of technology and the flow of time. The results of this paper could be practically used as the reasonable justifications of the policies for not only the competition management but also the alignment about the frequencies for mobile telecommunication.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.7
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• pp.3-11
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• 2017

UAV system has the limitation to allocate enough spectrum bandwidth for the operation of multiple UAVs due to the market expansion. In addition, the communication environment of UAV network varies dynamically due to the UAV's mobility. Thus, to operate the stable UAV system and maximize the transmission data rate, it needs to allocate the resource effectively in the limited bandwidth considering the given network environment. In this paper, we propose the resource allocation algorithm which can maximize the network throughput as well as satisfy the minimum data requirement for the UAV system operation in the given network environment based on TDMA(Time Division Multiple Access). By performance analysis, we show that the proposed algorithm can allocate the resource to satisfy the high network throughput as well as the minimum data requirement in the given network environment.

• Proceedings of the Korea Contents Association Conference
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• 2003.11a
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• pp.253-259
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• 2003

최근 각 이동통신사업별로 기존의 CDMA 방식을 이용하여 IMT-2000의 서비스에 해당되는 대용량 데이터서비스를 제공하고 있다. 그러나 각 사업자 별로 할당된 현재의 주파수대역으로는 영상서비스를 기본으로 하는 대용량 데이터서비스를 제공하기 어려운 상황이며, 새로운 주파수대역의 추가 분배가 필요한 상태이다. 본 논문에서는 ITU-R에서 제시하고 있는 권고안을 기초로 국내 이동통신서비스 확대에 요구되는 추가 스펙트럼 요구량을 산출하였으며, 디지털 이동통신서비스를 위해 필요한 스펙트럼 효율의 정량화 및 추가 소요 주파수 대역을 계산하는 방법을 정량화 하였다.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.5
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• pp.73-82
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• 2013

최근 차량 네트워크(VANET)는 차량 및 도로 안전에 관한 정보와 다양한 인포테인먼트 서비스 증가로, 기존 차량 통신에 고정적으로 할당된 주파수로는 요구되어지는 주파수 수요량을 충족하지 못할 것으로 예측된다. 이에 따라, 인지 무선(CR) 기술을 VANET 환경의 특징에 적합하게 적용함으로써, 동적인 주파수 사용으로 주파수의 활용도를 향상시키기 위한 연구가 큰 관심을 받고 있다. 본 고에서는 인지 무선을 이용한 차간 통신 이슈 및 연구 동향을 소개한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.6B
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• pp.508-516
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• 2006

The explosive growth of wireless network users and the existence of various wireless services have demanded high rate throughput as well as user's QoS guarantees. Towards this, this paper proposes QoS-oriented subcarrier allocation scheme considering the QoS provisioning of multiple users, which is major requirement for wireless network design point of view. This paper introduces joint RR/K&H combined with M-LWDF(Modified Largest Weighted Delay First) scheme throughout observing statistical channel behavior and real time queuing analysis for appropriate resource allocation tightly connected to multiuser scheduling. Accordingly, the system throughput can be enhanced, and the QoS demanded for delay sensitive services can be satisfied. Furthermore, the proposed scheme is applied for OFDMA(Orthogonal Frequency Division Multiple Access) systems to allocate sub-carriers in optimal way. The simulation results verify plausible performances of proposed resource allocation scheme via showing superior effective capacity under time-varying physical-layer channel behaviors.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.7B
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• pp.567-574
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• 2008

In this paper, we propose an optimal coverage extension scheme in the OFDMA based mobile multi-hop relay system. First, we propose an optimal frequency and time assignment scheme for maximizing system throughput and analyze the frame efficiency of schemes. Then, under the given BS capacity, we find the maximum number of relay hops that can be used to estimate the maximum coverage area of a BS in a multi-hop relay system. Analytical results show that the proposed scheme is efficient in coverage extension and throughput maximization in OFDMA based multi-hop relay system. Our work may be a rough guideline to control the parameters for multi-hop relay system optimization.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.8A
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• pp.829-837
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• 2008

A cellular system with fixed relays is considered to be a technology that can support high data transmission service to wide areas. However, either inter-cell interference or inter-sector interference that can be produced by adding relays to the cellular system with fixed relays does not guarantee high link performance to deteriorate function, so that resource allocation for avoidance of interference is very much important. In the paper, the cellular system performance with repeater relay has been compared with the cellular system performance with relay, and cell coverage expansion at the use of relay repeater has been compared. To compare, this paper has suggested resource allocation method to avoid inter-cell interference and inter-sector interference at installation of fixed relay on the cellular system. The proposed method can allocate different frequency resources on adjacent base stations and relays to reduce interference and to expand high data transmission area, and all of frequency bands are used at each sector to elevate efficiency of the frequency when base stations and relays operate simultaneously.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1995.10a
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• pp.82-86
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• 1995

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1992.04b
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• pp.75-75
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• 1992