• ETRI Journal
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• v.40 no.1
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• pp.89-100
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• 2018

Millimeter wave communication is one of the main disruptive technologies in upcoming 5G mobile networks. One of the first candidate applications, which will be commercially ready by 2020, is wireless backhaul links or wireless last mile communication. This paper provides an analysis of this use-case from radio engineering and implementation perspectives. Furthermore, preliminary experimental results are shown for a proof-of-concept wireless backhaul solution developed within the EU-KR 5GCHAMPION project, which will be showcased during the 2018 Winter Olympic Games in Korea. In this paper, we verify system level calculations and a theoretical link budget analysis with conductive and radiated over-the-air measurements. The results indicate that the implemented radio solution is able to achieve the target key performance indicator, namely, a 2.5 Gbps data rate on average, over a range of up to 200 m.

• Journal of the Korea Society of Computer and Information
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• v.21 no.11
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• pp.65-71
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• 2016

This paper proposes a novel traffic and resource management scheme based on Service Level Agreement (SLA) which allows to guarantee the quality of experience (QoE) for various high-quality mobile multimedia service users to a certain level. For this purpose, QoE-SLA coupling structure is considered and a novel scheme is suggested to suppress the processing delay of the mobile terminal and to decrease the transfer delay in the transmission network. According to simulation results, our proposed scheme can increase the total throughput and decrease the average delay by adjusting SLA.

• ETRI Journal
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• v.33 no.5
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• pp.704-711
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• 2011

This paper proposes hybrid distributed stochastic addressing (HDSA), which combines the advantages of distributed addressing and stochastic addressing, to solve the problems encountered when constructing a network in a ZigBee-based wireless sensor network. HDSA can assign all the addresses for ZigBee beyond the limit of addresses assigned by the existing distributed address assignment mechanism. Thus, it can make the network scalable and can also utilize the advantages of tree routing. The simulation results reveal that HDSA has better addressing performance than distributed addressing and better routing performance than other on-demand routing methods.

• ETRI Journal
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• v.31 no.2
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• pp.209-214
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• 2009

In this paper, we propose a novel test methodology for the detection of catastrophic and parametric faults present in analog very large scale integration circuits. An automatic test pattern generation algorithm is proposed to generate piece-wise linear (PWL) stimulus using wavelets and a genetic algorithm. The PWL stimulus generated by the test algorithm is used as a test stimulus to the circuit under test. Faults are injected to the circuit under test and the wavelet coefficients obtained from the output response of the circuit. These coefficients are used to train the neural network for fault detection. The proposed method is validated with two IEEE benchmark circuits, namely, an operational amplifier and a state variable filter. This method gives 100% fault coverage for both catastrophic and parametric faults in these circuits.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.9
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• pp.929-938
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• 2009

This paper presents a novel control methodology for communication network based nonlinear systems with time delay nature. We construct a nominal nonlinear control law for representing a linear model and a reset control system which is aimed for corrective control strategy to compensate system error due to uncertain time delay through wireless communication network. Next, online neural control approach is proposed for overcoming nonstationary statistical nature in the network topology. Additionally, DBN (Dynamic Bayesian Network) technique is accomplished for modeling of its dynamics in terms of casuality, which is then utilized for estimating prediction of system output. We evaluate superiority and reliability of the proposed control approach through numerical simulation example in which a nonlinear inverted pendulum model is employed as a networked control system.

• Proceedings of the IEEK Conference
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• 2007.07a
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• pp.171-172
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• 2007

The need for open architecture based IP network is becoming increasingly critical because the electric power industry has begun to upgrade to digital systems. In this paper, we implemented IPv6 testbed and experimented IPv6 performance actually for examination on IPv6 applications to electric power communication network. We achieved preliminary tests relevant to IPv6 to solve expected problems before.

• International Journal of Internet, Broadcasting and Communication
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• v.7 no.1
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• pp.66-69
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• 2015

Recently with the development of IT technology, the medical technology have been developed in various ways. Among them, WBAN can check the state of the patient in real time. However, the data generated by these techniques have a problem that they have heterogeneous properties depending on the type of sensors and devices. In this paper, we proposed a method using meta repository as a way to provide the sensing data of WBAN for the health care system by integrating along the HL7 standard item.

• International Journal of Internet, Broadcasting and Communication
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• v.7 no.1
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• pp.23-29
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• 2015

Energy constraints of wireless sensor networks are an important challenge. Data Transmission requires energy. Distance between origin and destination has an important role in energy consumption. In addition, the location of base station has a large impact on energy consumption and a specific method not proposed for it. In addition, a obtain model for location of base station proposed. Also a model for distributed clustering is presented by cluster heads. Eventually, a combination of discussed ideas is proposed to improve the energy consumption. The proposed ideas have been implemented over the LEACH-C protocol. Evaluation results show that the proposed methods have a better performance in energy consumption and lifetime of the network in comparison with similar methods.

• International Journal of Internet, Broadcasting and Communication
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• v.7 no.1
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• pp.30-35
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• 2015

The most important factor within the wireless sensor network is to have effective network usage and increase the lifetime of the individual nodes in order to operate the wireless network more efficiently. Therefore, many routing protocols have been developed. The LEACH protocol presented by Wendi Hein Zelman, especially well known as a simple and efficient clustering based routing protocol. However, because LEACH protocol in an irregular network is the total data throughput efficiency dropped, the stability of the cluster is declined. Therefore, to increase the stability of the cluster head, in this paper, it proposes a stochastic cluster head selection method for improving the LEACH protocol. To this end, it proposes a SH-LEACH (Stochastic Cluster Head Selection Method-LEACH) that it is combined to the HEED and LEACH protocol and the proposed algorithm is verified through the simulation.

• Proceedings of the Korean Society of Computer Information Conference
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• 2015.07a
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• pp.202-203
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• 2015

무선 센서 네트워크는 제약된 하드웨어와 개방된 환경으로 인해 싱크 홀 공격에 취약한데 이를 위해서 INSENS가 제안되었다. 이러한 INSENS는 베이스 스테이션과 센서 노드들 사이에 거리를 기반으로 경로를 설정하므로 이벤트가 자주 발생할 경우 특정 경로에 노드들은 트래픽이 증가하여 에너지 불균형을 가진다. 이러한 문제점을 해결하기 위해 본 논문에서는 네트워크 상황을 고려하여 균형적으로 에너지를 소모하게 하는 퍼지 시스템 기반의 효율적인 경로 설정 방법을 제안한다. 퍼지 시스템은 배터리 잔량, 홉 수, 경로설정 횟수의 입력을 통해 네트워크의 효율적인 경로를 설정한다. 그러므로 제안 기법은 효율적인 경로 선택으로 트래픽을 분산시켜 전체 센서 네트워크의 수명을 연장한다.