• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.6
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• pp.141-145
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• 2021

Various types of memory architectures have been developed, and various compiler optimization techniques have been studied to efficiently use them. In particular, since a memory is a major component that determines performance in mobile computing devices, various optimization techniques have been developed to support them. Recently, a lot of research on hybrid type memory architecture is being conducted, so various compiler techniques are being studied to support it. Existing compiler optimization techniques can be used to achieve the required minimum performance and constraint on low power according to market requirements. References for determining the low-power effect and the degree of performance improvement using these optimization techniques are not properly provided yet. This study was conducted to provide the experimental results of the existing compiler technique as a reference for the development of multibank memory architecture.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.4
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• pp.93-98
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• 2019

On today, optical system are the next generation weapon systems being studied in many countries, starting from USA. One of the most important technologies in optical system is a high-speed automatic target tracking system that can continuously track high-speed moving small targets. This paper designs an automatic target tracking system based on a correlated trekker that is robust against rapid shape changes for fast moving targets and small targets at a distance. The proposed system showed about 98% success rate in response to the targets that are under a complex background such as drone, ranger, etc.

• International Journal of Internet, Broadcasting and Communication
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• v.13 no.4
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• pp.103-111
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• 2021

In modern society, digital lifestyles are spreading to minimize contact with people and to receive contactless information. The spread trend has established an unmanned distribution system in which transactions through contactless technologies such as kiosks and chatbots are activated in face-to-face transactions with sellers and consumers. In order to streamline logistics supply worldwide, digital new deal based joint logistics hubs, unmanned courier storage platforms, and fresh logistics based last mile services have been developed into unmanned logistics systems, focusing on the intelligent logistics system automation process. Unmanned courier storage system installed in urban areas and home to daily logistics where volume is concentrated are provided with fresh logistics services through cold chain and receiving freights in contactless environments. Development is also underway to minimize safety accidents caused by courier services, such as managing various information based on the integrated control system. This paper defines the concept of integrated operation for the development of a platform for contactless unmanned courier storage device developed into next-generation logistics system. In addition, we intend to develop systems engineering-based output for deriving safety requirements and specifications by identifying risk sources that may occur in the operational scenario. Therefore, the goal is to establish a foundation for safety and reliability between interfaces of logistics systems to be installed in apartment and subway station environments that want to provide unmanned logistics services to various consumers.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.4
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• pp.37-42
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• 2021

NOMA (Non-orthogonal multiple Access) system has been focused on the next generation cellular system for higher spectral efficiency. However, this requires user scheduling as the NOMA system is a multi-user system which accesses simultaneously. There are two representative scheduling schemes, proportionate scheduling (FP) and cumulative distribution function (CFD) scheduling. The PF scheduling is applied, the cell edge user is hard to obtain a transmit opportunity. Recently, CDF scheduling is obviously noted that it offers the same possibility of transmission for a user regardless of the location in a cell. We consider an uplink NOMA system with CDF scheduling, and obtain the channel access probabilities, the outage probabilities of the system with different number of users and different kinds of weights through simulation. The results indicate that the likelihood of each user accessing the channel is the same and the probability of failure decreases as the number of users increases. We found that the effect of the probability of failure is negligible as the weight of the cell edge user increases.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.3
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• pp.49-55
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• 2022

In the next generation mobile communication systems, hybrid massive multiple-input multiple output (MIMO) can be used to highly improve an achievable rate without increasing the number of RF chains. Recently, successive-interference-cancellation (SIC) based hybrid precoder design scheme was proposed to reduce the complexity. However, since this scheme uses simple diagonal matrix for baseband precoding, it cannot solve an interference problem between the transmitted streams. Also, there is a limitation for improving the data rate because of the use of one phase shifter for analog precoding. To solve these problems, in this paper we propose a digital precoding based on the SVD of the effective channel and an analog precoding using two phase shifters. Through simulation, we show that the proposed scheme has better achievable rate and SINR performances than the conventional one.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.5 s.347
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• pp.24-34
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• 2006

The broadband access network is a worldwide trend and the related IPTV service is booming. However, the IPTV deployment has been delayed in Korea because of the business relationship between the communication and broadcasting area and the lack of the related laws. As a means to the development of FTTH-based high-quality service platform and next-generation equipment, ETRI has been building own FTTH service center with a network operation center and IPTV service equipments, also connecting it with commercial FTTH infrastructures made by network operators. In this paper, we describe the related technologies about FTTH-based IPTV testbed.

• IEIE Transactions on Smart Processing and Computing
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• v.2 no.5
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• pp.255-265
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• 2013

3DTV is expected to be a promising next-generation broadcasting service. On the other hand, the visual discomfort/fatigue problems caused by viewing 3D videos have become an important issue. This paper proposes a perceptual quality assessment metric for a stereoscopic video (SV-PQAM). To model the SV-PQAM, this paper presents the following features: temporal variance, disparity variation in intra-frames, disparity variation in inter-frames and disparity distribution of frame boundary areas, which affect the human perception of depth and visual discomfort for stereoscopic views. The four features were combined into the SV-PQAM, which then becomes a no-reference stereoscopic video quality perception model, as an objective quality assessment metric. The proposed SV-PQAM does not require a depth map but instead uses the disparity information by a simple estimation. The model parameters were estimated based on linear regression from the mean score opinion values obtained from the subjective perception quality assessments. The experimental results showed that the proposed SV-PQAM exhibits high consistency with subjective perception quality assessment results in terms of the Pearson correlation coefficient value of 0.808, and the prediction performance exhibited good consistency with a zero outlier ratio value.

• International journal of advanced smart convergence
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• v.8 no.4
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• pp.34-39
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• 2019

Millimeter-wave (mmWave) and Non-orthogonal multiple access (NOMA) are expected to be the major techniques that lead to the next generation wireless communication. NOMA provides a high spectrum efficiency by sharing of spatial resources among users in the same frequency band. Meanwhile, millimeter-wave gives a huge underutilized bandwidth at extremely high frequency band (EHF) which covers 30GHz to 300GHz. These techniques have been proven in several recent literatures to achieve high data rates. The combination of NOMA and millimeter-wave techniques further improves average sum capacities, as well as reduces the interference compared to conventional wireless communication systems. In this paper, we focus on hybrid NOMA system working in millimeter-wave frequency. We propose a clustering algorithm used for a hybrid NOMA scheme to optimize the usage of wireless resources. The proposed clustering algorithm adds several conditions in grouping users and defining clusters to increase the probability of the successful superposition decoding process. The performance of the proposed clustering algorithm is investigated in hybrid NOMA system and compared with the conventional orthogonal multiple access (OMA) scheme.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2017.06a
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• pp.133-134
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• 2017

본 논문에서는 차세대 방송 표준 ATSC (Advanced Television Systems Committee) 3.0 기반 LDM (Layered Division Multiplexing) 및 스케일러블 비디오 코덱 (Scalable Video Codec) 을 활용한 지상파 방송시스템 기술을 살펴보고 그 성능을 비교 분석한다. 코어 레이어 (Core Layer)와 인핸스드 레이어 (Enhanced Layer)로 구성된 LDM 기반 PLP (Physical Layer Pipe)에, 스케일러블 비디오 코딩이 적용된 베이스 레이어 (Base Layer)와 인핸스먼트 레이어 (Enhancement Layer) 스트림을 각각 전송함으로써 하나의 RF 채널에 두 개 이상의 서비스를 전달할 경우 채널 효율을 극대화 할 수 있다. 본 논문에서는 이동 및 고정용 서비스, 즉 두 개의 서비스를 전송할 때 제안된 LDM 및 스케일러블 비디오 코덱을 사용한 기술과 TDM (Time Division Multiplexing) 및 Simulcast 를 적용한 기술과의 성능 비교를 통해 제안된 기술의 우수성을 검증하고자 한다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2011.07a
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• pp.316-319
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• 2011

본 논문에서는 그 동안 국내 지상파 DTV 방송의 임시대역으로 사용해 오던 Ch.61~69(752~806MHz)를 포함한 700MHz 대역의 주파수 Ch.52~69(698~806MHz)를 지상파방송 디지털전환 이후 경매에 의해 통신에 할당하려는 방송통신위원회의 정책 추진에 대한 기술적, 정책적 타당성을 분석하고, 디지털 방송에서의 주파수 필요성과 상관성을 비교하여 바람직한 주파수 정책에 대한 방향을 모색하고자 하였다. 디지털 방송의 경우 이 대역에서 차세대방송용으로 활용할 계획을 가지고 있으며 방송 콘텐츠산업과 디스플레이산업의 발전 촉매제로 간주하고 있다. UDTV(Ultra-HDTV) 및 Full-HD 3DTV 를 비롯하여 HD 혹은 Full-HD MMS(Multi Mode Service) 서비스와 무안경식 3DTV, 홀로그래피 3DTV 와 같은 차세대방송 환경 구축을 위해서는 우선 700MHz 대역의 주파수의 추가 확보와 정책적 지원의 필요성이 요구되고 있다. 본 논문에서는 무선통신과 방송분야의 주파수 요구 내용을 비교함으로써 바람직한 주파수 할당 정책에 대한 대안을 제시하였다.