• Journal of the Institute of Electronics and Information Engineers
• /
• v.53 no.6
• /
• pp.3-14
• /
• 2016

Recently, researches for new waveforms have been carried in order to satisfy KPI for 5G mobile communication system. UFMC and FBMC are well known as ways to reduce OOB power. In this paper, we analyze spectrum of OFDM, UFMC, and FBMC system under nonlinear HPA environment. And then we evaluate and analyze performance of these systems under the same environment. As simulation results, OOB power of OFDM, UFMC, and FBMC increases with HPA nonlinearity increasement. Especially, OOB power of FBMC is the largest increase due to HPA nonlinearity. Also, BER performance of these systems is degraded by increasement of HPA nonlinearity. Therefore, In this paper, we can confirm that a system with low-complexity and high-speed processing is advantageous, because BER performance and OOB power characteristic of these systems are degraded to similar level, when these systems are implemented in real world.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.5 no.1
• /
• pp.41-51
• /
• 2001

In this paper, we presented that the performance of the TCM(Trellis Coded Modulation) using the Euclidean distance is better than that of the convolutional code using the hamming distance under the same bandwidth efficiency. And the TCM DECODER for next generation mobile communication replacing the using convolutional decoder is implemented. Also, for the implementation of the TCM DECODER, the convolutional decoder and the TCM decoder were made by C-language and simulated under AWGN channel with respect to the hard decision and the soft decision. So we proved that performance of the TCM is better than that of the convolutional code. From this result, TCM DECODER, of which constraint length is 3, 5 or 7 and which use the soft decision method, was implemented using the AHDL(Altera Hardware Description Language) and fortified using the Max+plus H version 8.2 of Altera corporation.

• The Journal of Korean Institute of Next Generation Computing
• /
• v.13 no.5
• /
• pp.39-50
• /
• 2017

Moving object tracking techniques can be considered as one of the most essential technique in the video understanding of which the importance is much more emphasized recently. However, irregularity of light condition in the video, variations in shape and size of object, camera motion, and occlusion make it difficult to tracking moving object in the video. Swarm based methods are developed to improve the performance of Kalman filter and particle filter which are known as the most representative conventional methods, but these methods also need to consider dynamic property of moving object. This paper proposes adaptive parameter control method which can dynamically change weight value among parameters in particle swarm optimization. The proposed method classifies each particle to 3 groups, and assigns different weight values to improve object tracking performance. Experimental results show that our scheme shows considerable improvement of performance in tracking objects which have nonlinear movements such as occlusion or unexpected movement.

• The Journal of Korean Institute of Next Generation Computing
• /
• v.13 no.5
• /
• pp.51-70
• /
• 2017

The reliability of broadcasting over vehicular ad hoc networks (VANETs) is one of the most critical factors for driving safety applications. There exists limitations to improve the reliability of broadcast transmissions in saturated VANETs where previous proposals in literature tackle the problem by heuristically adapting the size of the contention window (CW). This paper considers improving the reliability by proposing a new probability model based on the counting methods of permutations and combinations, which counts all the possible cases of broadcast failures in a single-hop broadcast transmission for a given CW. From the model, we calculate the best CW size given the number of contention nodes, which significantly improves the reliability and satisfying the timely dissemination of emergency broadcasting messages. Through extensive VANET simulations with varying densities, we show that our model maintains near 100 percent success rate for single-hop broadcast as well as multi-hop broadcast (e.g. 40 hops) and achieves minimal broadcast delay.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.14 no.5
• /
• pp.917-926
• /
• 2019

At present, TICN has been developed and distributed for military command control. TICN is known as the 3.5G mobile communication technology based on WiBro, which shows technical limitation in the field operation situation. Accordingly, the drone-type base station platform is attracting attention as an alternative to overcome technical limitations such as difficulty in securing communication LoS and limiting expeditious network configuration. In this study, we performed simulation performance evaluation of drone-type base station operation in 28 GHz that is considered most suitable for cellular communication within mmWave frequency band. Specifically, we analyzed the changes in throughput and fairness performance according to radio resource management policies such as frequency reuse and scheduling in multi-cell topology. Through this, we tried to provide insights on the operation philosophy on drone-type base station.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.5 no.5
• /
• pp.941-950
• /
• 2001

In this paper, we present the integrated network architecture for supporting mobile IP in third generation mobile communication networks, and propose the end-to-end QoS control mechanisms of DiffServ and QoS control functions of each network element in the proposed network. First, the QoS supporting schemes of IMT-2000 are described. Second, the necessities of integrating the networks are discussed and the integrated architecture are proposed. Third, the mapping between wireless channels and DiffServ classes are presented. Finally, the end-to-end QoS control mechanisms are proposed. We also analyze the link level protocols with QoS provisioning for mobile multimedia assuming that the system support voice and data traffic simultaneously. In case of data traffic, the delay and throughput of SREJ ARQ and Type-1 Hybrid ARQ scheme are compared, and In case of voice traffic, the packet loss rate of BCH coding is analyzed according to the varying data traffic loads. The results indicate that the adaptive link level protocols are efficient to meet the QoS requirements while the complexities are increased.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.14 no.1
• /
• pp.195-201
• /
• 2014

In this paper, an AccessPoint compact microstrip patch antenna was designed by using L-shaped feeding structure of a Fractal Structure and the compact antenna can be obtained by the rare formed presence of the resonance flow which is called "Crossed-Diagonal". CST's MicroWave5.0 was used for the design. As the operating characteristics of the patch antenna, it showed the characteristic of 1031 [MHz] or 29.4% in the range of 3.202 [GHz] ~ 4.233 [GHz] when an input return loss is less -10 [dB] and VSWR 2:1, also as it is in this paper, we got simulation results such as, gains of the E-plane and H-plane are 8.7 [dBi] and 8.6 [dBi] for this is the single patch, and 3 [dB] beamwidth is $43.9^{\circ}$ at E-plane and $78.7^{\circ}$ at H-plane.

• The Journal of the Convergence on Culture Technology
• /
• v.7 no.2
• /
• pp.333-338
• /
• 2021

Development of 5th generation mobile telecommunication technology is visualizing ideal hyper-connected social information and communication technology (ICT). In particular, virtual reality (VR) technology is at the starting point for new expansion and leaps. This work defines virtual reality as media in this context and collects and analyzes discourse on its scalability around space and communication theory. We first elaborated the concept, starting with the early discussions of the virtual reality concept in 1990, and discussed the relationship between the physical world and digital information, expression and interaction immersion as a medium, simulation, art creation theory, and finally evolutionary development. In conclusion, beyond the discourse on the technology of virtual reality, academic subjects were required to have theoretical frameworks on cognitive science, neuroscience, social science, and humanities issues (ethics, personality, etc.) for the development and evolution of virtual reality. In other words, it is time for the evolution of virtual reality to be discussed, which can be moved beyond.

• 한국경영정보학회:학술대회논문집
• /
• 2007.11a
• /
• pp.309-315
• /
• 2007

SK텔레콤은 급변하는 이동통신시장 환경의 변화에 적절히 대응하기 위하여 지난 10여 년간 사용해 온 메인프레임 기반의 COIS 시스템을 중단하고 Unix 기반의 NGM 시스템으로 다운사이징하기로 결정하였다. 2002 년 9 월 SK 텔레콤은 차세대 IT 인프라 혁신 전략 프로젝트를 완료하고 이에 근거하여 2003 년 말 1 단계 프로젝트를 추진하게 된다. 그러나 개발 툴의 문제점, Governance 의 확보 실패 등 문제점이 계속 누적되어 2005년에 접어들어서는 총체적 난국 상황에 봉착하게 되었다. 2005 년 2 월 자체 점검 결과 개발 진척도는 50%에 불과한 상황이었다. 결국 2005 년 3 월, NGM 추진본부는 프로젝트의 추진 중단을 선언하기에 이르렀다. NGM 프로젝트는 처음부터 재 검토하여 Re-planning 을 실시한 후 구축을 재개하기로 결정하였다. 2005 년 5 월 NGM 프로젝트의 Re-plan 이 수립되었다. 우선 Turn-key 방식의 문제점을 해소하기 위하여 SK 텔레콤이 구축의 총책임을 떠맡고, SK C&C 가 시스템 이행에 대한 책임을 지는 Governance 체제를 확립하였다. 또한 2 단계 프로젝트에서는 NGM 프로젝트를 기술적으로 원점부터 재 검토하여 이전과는 근본적으로 다른 In-House 구축 접근방식을 채택하기로 하였다. 2 단계 프로젝트에서 관심을 집중한 기술적 의사결정 영역은 크게 (1) 미들웨어 및 개발프레임워크의 적용, (2) DB 아키텍처의 결정 및 슬림화, (3) 시스템 성능 개선 등의 세 분야로 집약할 수 있다. 이 논문에서는 이들 각각의 분야를 구체적으로 검토하였다. 결국 2006 년 10 월 9 일 메인프레임 기반의 COIS 는 Shut-down 되어 가동을 멈추었고, Unix 기반의 NGM 시스템이 가동을 개시함으로써 차세대 마케팅을 본격 추진하기 위한 다운사이징 프로젝트가 성공적으로 완수되었다.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.13 no.5
• /
• pp.121-133
• /
• 2013

Defect-free transfer service on the Next-generation wireless network extensive roaming mobile node (MN) to provide efficient mobility management has become very important. MIPv6(Mobility IPv6) is one of mobility management scheme proposed by IETF(Internet Engineering Task Force), and IPv6-based mobility management techniques have been developed in various forms. One of each management techniques, IPv6-based mobility management techniques for PMIPv6 (MIPv6) system to improve the performance of a variety of F-PMIPv6 (Fast Handover for Proxy MIPv6) is proposed. However, the F-PMIPv6 is cannot be excellent than PMIPv6 in all scenarios. Therefor, to select a proper mobility management scheme between PMIPv6 and F-PMIPv6 becomes an interesting issue, for its potenrials in enhancing the capacity and scalability of the system. In this paper, we develop an analytical model to analyze the applicability of PMIPv6 and F-PMIPv6. Based on this model, we design an Secure Smart Mobility Support(SSM) scheme that selects the better alternative between PMIPv6 and F-PMIPv6 for a user according to its changing mobility and service characteristics. When F-PMIPv6 is adopted, SSM chooses the best mobility anchor point and regional size to optimize the system performance. Numerical results illustrate the impact of some key parameters on the applicability of PMIPv6 and F-PMIPv6. Finally, SSM has proven even better result than PMIPv6 and F-PMIPv6.