• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.5
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• pp.328-336
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• 2013

One of the important processes in device-to-device communication is the discovery of proximate devices. In order to perform precise discovery of devices, the distance information among all the device pairs should be gathered by each device sending a discovery signal in turn and the other devices receiving the signal. However, periodic discovery signal transmission by every device might require too long discovery period or too large resource for discovery. Above all, some discovery information might be lost due to several practical reasons and it may take substantial amount of time to obtain all the necessary information. In this paper, we propose a proximate-device-discovery method using partial discovery information in order to reduce the resource for discovery and support the cases in which some discovery information can be lost. We also discuss discovery probabilities with partial discovery information.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.11
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• pp.1754-1766
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• 1993

The application of VXIbus system, an Industry standard, is rapidly spreading with its ability to offer the easiness of integration from GPIB and the fast data transmission from VMEbus system. Compared with VXIbus Register Based Device, VXIbus Message Based Device has a drawback In the aspect of speed. But it is possible to utilize high level ASCII commands to control a Message Based Device, therefore system integration is much easier with Message Based Device than with Register Based Device. And, the FFT analyzer is an instrument for signal analysis which can be inexpensively implemented to be fast and have high resolution. Its wide ability of analysis presents numerous application. So, it is necessary to apply VXIbus system to FFT analyzer. In this paper, the implementation of FFT analyzer is performed using a DSP module and by implementing all A/D conversion circuit and a control module which performs VXIbus interface. The device can be controlled by Slot0 Commender which supports VXIbus Shared Memory Protocol through VXIbus.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.4
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• pp.1941-1960
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• 2019

Unmanned aerial vehicles (UAVs), acting as mobile base stations (BSs), can be deployed in the typical fifth-generation mobile communications (5G) scenarios for the purpose of substantially enhancing the radio coverage. Meanwhile, UAV aided underlay device-to-device (D2D) communication mode can be activated for further improving the capacity of the 5G networks. However, this UAV aided D2D communication system is more vulnerable to eavesdropping attacks, resulting in security risks. In this paper, the D2D receivers work in full-duplex (FD) mode, which improves the security of the network by enabling these legitimate users to receive their useful information and transmit jamming signal to the eavesdropper simultaneously (with the same frequency band). The security communication under the UAV coverage is evaluated, showing that the system's (security) capacity can be substantially improved by taking advantage of the flexible radio coverage of UAVs. Furthermore, the closed-form expressions for the coverage probabilities are derived, showing that the cellular users (CUs)' secure coverage probability in downlink transmission is mainly impacted by the following three factors: its communication area, the relative position with UAV, and its eavesdroppers. In addition, it is observed that the D2D users or DUs' secure coverage probability is relevant to state of the UAV. The system's secure capacity can be substantially improved by adaptively changing the UAV's position as well as coverage.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.2
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• pp.202-215
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• 2013

The generalization trend of smartphones has brought many smartphone games into daily lives. These games are mainly dependent on the interactions on the display of the phone using finger touches. On the other hand, functions for detecting the positions and actions of the phones such as gyro-sensors have been rapidly developed over the former orientation sensors and acceleration sensors. Though it has become technologically possible to detect the users' motion via the smartphone devices and to use the phone device directly as the game device, it is hard to find the actualized cases. This paper proposes a new paradigm that includes basic frameworks and algorithms for the games combining the motion tracking and mutual communications on the smartphones and presents the details of its implementation and results.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.7
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• pp.3431-3445
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• 2017

Due to the advantages of low transmit power consumption, high spectral efficiency and extended system coverage, Device-to-Device (D2D) communication has drawn explosive attention in wireless communication field. Considering that intra-cell interference caused between cellular signals and D2D signals, in this paper, a network coding-based D2D relay cooperative transmission algorithm is proposed. Under D2D single-hop relay transmission mode, cellular interfering signals can be regarded as useful signals to code with D2D signals at D2D relay node. Using cellular interfering signals and network coded signals, D2D receiver restores the D2D signals to achieve the effect of interference suppression. Theoretical analysis shows that, compared with Amplify-and-forward (AF) mode and Decode-and-forward (DF) mode, the proposed algorithm can dramatically increase the link achievable rate. Furthermore, simulation experiment verifies that by employing the proposed algorithm, the interference signals in D2D communication can be eliminated effectively, and meanwhile the symbol error rate (SER) performance can be improved.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.6B
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• pp.325-333
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• 2007

An OS requires the device driver to control hardware IPs at application level. Development of a device driver requires specific acknowledge for target hardware and OS. In this paper, we present a system which generates a device driver together with an interface circuit. In the proposed system, an efficient device driver is generated by selecting a basic device driver skeleton, a function module code, and a header file table from the pre-constructed library and an interface circuit is constructed such that the generated device driver operates correctly. The proposed system is evaluated by generating a TFT-LCD device driver on the ARM922T core with 3.5 inch Samsung TFT-LCD in ARM-Linux environment. Experiment result shows that the writing time on the LCD is decreased by 1.12% and the compiled code size is increased by 0.17% compared to the manually generated one. The automatically generated device driver has no performance degradation in the latency of hardware control at the application program level. The system development time can be reduced using the proposed device driver generation system.

• Journal of Satellite, Information and Communications
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• v.6 no.2
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• pp.10-14
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• 2011

This paper suggests the method to calculate radiation limit of ISM(Industrial Scientific Medical) equipment in order to protect radio device in the situation that ISM equipment and radio device are operated in near distance. The factor for correction and protection ratio which is need for protecting radio device were considered to calculate radiation limit of ISM equipment. Also, the scenario which is required to limit radiation power of ISM equipment was referred and the S/W for calculation of radiation limit was developed by using GUI(Graphical User Interface) on Matlab. The suggested method for calculation of radiation limit of ISM equipment will be used to protect radio device from ISM equipment.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37A no.10
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• pp.885-894
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• 2012

Currently, Demand of data traffic has rapidly increased by popular of smart device. It is very difficult to accommodate demand of data traffic by limited resource of base station (BS). To solve this problem, method has proposed that the Device-to-Device (D2D) reduce frequency overload of the BS and all of the user equipment (UE) inside the BS and neighbor BS don't allow communicating directly to BS. However, in LTE-Advance system cellular link and sharing radio resources of D2D link, the strong interference of the cellular network is still high. So we need to eliminate or mitigate the interference. In this paper, we use the transmission power control method and Soft Frequency Reuse (SFR) resource allocation method to mitigate the interference of the cellular link and D2D link. Simulation results show that the proposed scheme has high performance in terms of Signal to Noise Ratio (SINR) and system average throughput.

• Journal of Information Technology Services
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• v.4 no.2
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• pp.71-78
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• 2005

The beginning of Web Services was understood as efficient technology for application integration in the internet, thus it was used to integrating the distributed enterprise applications or the e-business applications between partners. But, recently the usage trend of Web Services is largely spreaded out wireless network applications beyond the internet applications. The main reasons are that Web Services is the international standard of W3C, and Web Services is based on XML that is independent of the specific internal implementations such as platform, programming languages, communications networks etc. Currently Major company of Web Services such as MS, IBM, etc. focus on the research about technology for integrating various devices. In this paper, we define and explain technical issues for adapting web services to ubiquitous Environment.

• ETRI Journal
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• v.31 no.1
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• pp.10-20
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• 2009

In this paper, a video broadcasting system between a home-server-type device and a mobile device is proposed. The home-server-type device can automatically extract semantic information from video contents, such as news, a soccer match, and a baseball game. The indexing results are utilized to convert the original video contents to a digested or arranged format. From the mobile device, a user can make recording requests to the home-server-type devices and can then watch and navigate recorded video contents in a digested form. The novelty of this study is the actual implementation of the proposed system by combining the actual IT environment that is available with indexing algorithms. The implementation of the system is demonstrated along with experimental results of the automatic video indexing algorithms. The overall performance of the developed system is compared with existing state-of-the-art personal video recording products.