• Journal of Korea Society of Industrial Information Systems
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• v.14 no.4
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• pp.8-15
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• 2009

Relay-assisted multi-input multi-output (MIMO) technique has become a promising candidate for next generation broadband wireless communications for high speed access. In this paper, we propose channel selective relay-based MIMO transmission system. The performance of relay-based system can be improved by using the subcarriers selectively based on the channel condition between relay and mobile station. Simulation results show that the proposed relay-based system considerably outperforms the conventional relay-based system.

• Journal of Advanced Navigation Technology
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• v.14 no.5
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• pp.684-690
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• 2010

Recently, the NG(Next Generation) system is studied for supporting convergence of various services and multi mode of single terminal. And a demand of user for taking the various services is getting increased, for supporting these services, many systems being able to transmit a large message have been appeared. In the NG system, it has to be supporting the CDMA and WCDMA besides the tele communication systems using OFDM method with single terminal An intergrated system can be improved with adopting of SoC technique. For adopting SoC technique on the intergrated terminal, we have to solve the non linear problem of HPA(High Power Amplifier). Nonlinear characteristic of HPA distorts both amplitude and phase of transmit signal, this distortion cause deep adjacent channel interference. We adopt a polynomial pre-distortion technique for this problem. In this paper, a noble modem design for NG mobile communication service and a method using polynomial pre-distorter with PAPR technique for counterbalancing nonlinear characteristic of the HPA are proposed.

• The Journal of Korean Institute of Next Generation Computing
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• v.13 no.3
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• pp.60-71
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• 2017

Smart devices such as smart phones, smart TVs, and smart pads have become essential devices in recent years. As the popularity and demand grows, the performance of smart devices is also getting better and users are dealing with a lot of things such as education and business using smart devices instead of desktop. However, smart devices that still have poor performance compared to desktop, even with improved performance, have difficulty running high performance applications due to limited resources. In this paper, we propose a load balancing algorithm applying the characteristics of smart devices to overcome the resource limitations of devices. in order to verify the algorithm, we implemented the algorithm after adding the distributed processing system service in Android platform. After constructing the cluster on the smart device, various experiments were conducted. Through the analysis of the test results, it is confirmed that the proposed algorithm efficiently improves the overall distributed processing performance by effectively aggregating different amounts of computing resources in heterogeneous smart devices.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.2
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• pp.23-34
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• 2013

Over the past several decades in the microelectronics industry, devices have gotten smaller, thinner, and lighter, without any accompanying degradation in quality, performance, and reliability. One permanent and deniable trend in packaging as well as wafer fabrication industry is system integration. The proliferating options for system integration, recently, are driving change across the overall semiconductor industry, requiring more investment in developing, ramping and supporting new die-, wafer- and board-level solution. The trend toward 3D system integration and miniaturization in a small form factor has accelerated even more with the introduction of smartphones and tablets. In this paper, the key issues and state of the art for system integration in the packaging process are introduced, especially, focusing on ease transition to next generation packaging technologies like through silicon via (TSV), 3D wafer-level fan-out (WLFO), and chip-on-chip interconnection. In addition, effective solutions like fine pitch copper pillar and MEMS packaing of both advanced and legacy products are described with several examples.

• The KIPS Transactions:PartC
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• v.16C no.2
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• pp.189-198
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• 2009

Mobile RFID system is a next generation technology which combines the existing RFID systems with mobile systems. It is newly expected to provide additional services and will be broadly used in everyday life; however, it sometimes causes the privacy or security problems generated by existing RFID systems and the additional privacy or security problems. Moreover, even if many methods have been proposed to solve those problems, it is still difficult to adapt to reality or to guarantee the security perfectly. Therefore, in this paper, we propose the secure and practicable privacy protection mechanism suitable to mobile RFID systems. proposing mechanism is applicable the mechanism to Private Zone of mobile RFID systems which require to protect the privacy. This mechanism suggests that own tagging-products needed to protect privacy using mobile reader of personal don't provide any information to other readers except their own reader. In addition to, proposing mechanism is the efficient mechanism which largely reduces the process to maintain the synchronization when happen to the DoS attack or system error.

• Journal of Korean Institute of Industrial Engineers
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• v.29 no.2
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• pp.135-144
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• 2003

Traffic performance in a microcellular system is much more affected by cell dwell time and channel holding time in each cell. Cell dwell time of a call is characterized by its mobility pattern, i.e., stochastic changes of moving speed and direction. Cell dwell time provides important information for other analyses on traffic performance such as channel holding time, handover rate, and the average number of handovers per call. In the next generation mobile communication system, the cell size is expected to be much smaller than that of current one to accommodate the increase of user demand and to achieve high bandwidth utilization. As the cell size gets small, traffic performance is much more affected by variable mobility of users, especially by that of pedestrians. In previous work, analytical models are based on simple probability models. They provide sufficient accuracy in a simple second-generation cellular system. However, the role of them is becoming invalid in a picocellular environment where there are rapid change of network traffic conditions and highly random mobility of pedestrians. Unlike in previous work, we propose an improved probability model evolved from so-called Random walk model in order to mathematically formulate variable mobility of pedestrians and analyze the traffic performance. With our model, we can figure out variable characteristics of pedestrian mobility with stochastic correlation. The above-mentioned traffic performance measures are analyzed using our model.

• Journal of Korea Society of Industrial Information Systems
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• v.22 no.3
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• pp.19-26
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• 2017

In this paper, a Linear Error Correction Code, Which is Applicable to Next Generation Wireless Communication System Technology, is Constructed Based on Performance Comparison and Transmission Based on the Premise of High Performance Mobile Rate Enhancement System. This is Because Data Rates are Becoming an Important Issue in Reed-Solomon Codes and Linear Error Code (LDPC) Used in the Physical Layer of Digital Communication and Broadcasting Technologies. Therefore, this paper Simulates the Performance of Reed - Solomon Code and LDPC Applied to Mobile Broadcasting DVB (Digital Video Broadcasting) System and Mobile Broadcasting in Digital Communication and Broadcasting, At this time, Technical Aspects of the Transmission Efficiency and Performance of the LDPC Replacing the Existing Reed-Solomon Code have been Verified from the Viewpoint of Efficiency.

• Journal of KIISE:Computing Practices and Letters
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• v.6 no.1
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• pp.93-102
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• 2000

Processors for a base station controller such as call control processor have to serve usersdemand. Some of processors have been still used for the processing of call and 0&M (operation and maintenance) management by adopting embedded board type. This type can not provide users with a wide variety of environments for testing and debugging. User environments are regarded as a primary system factor in most systems and this is particularly so in designing and implementing the processor for base station controller in mobile communication systems. We describe the design and implementation of new user environment tool named QUEST for the next generation mobile communication system, IMT-2000. The simulation results of performance evaluations demonstrate that our system performs well for a base station controller without performance degradation.

• Journal of information and communication convergence engineering
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• v.13 no.3
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• pp.167-171
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• 2015

A radio over fiber (RoF) system is a kind of analog optical transmission system and considered as a strong candidate for the next-generation fronthaul link in the future mobile network. In RoF systems, nonlinearity compensation is essential to increase the link capacity. In this paper, we propose a nonlinearity detection and compensation scheme using a monitoring channel in RoF systems. A monitoring channel is added at the transmitter site and used for transmitting a reference signal in an RoF transmission. The nonlinearity in the RoF transmission is detected by comparing the received monitoring signal and the original reference signal at the receiver site. Finally, the nonlinearity is compensated at the receiver by giving the reverse function of the detected nonlinearity. Our results show that the proposed scheme can almost remove the error vector magnitude degradation induced by the nonlinearity in the RoF system.

• Journal of Satellite, Information and Communications
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• v.12 no.2
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• pp.94-98
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• 2017

In this paper, we design a transmission / receiver structure to provide additional data service based on Mobile MMT in hybrid network environment. Mobile MMT is an extended standard of MMT, the next generation multimedia transmission protocol. MMT defines technologies for efficiently transmitting multimedia and supporting various types of data transmission and bidirectional services over heterogeneous networks based on IP. The Mobile MMT further defines the extended functions to provide functions specific to the mobile network based on the existing MMT technology. In this paper, we design and propose a additional data service scenario and additional data transmission / receiver structure that can receive additional data related to contents delivered through broadcasting network and additional data such as traffic, weather, traveler information related to user information.