• Journal of Broadcast Engineering
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• v.14 no.2
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• pp.107-113
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• 2009

In Digital On-Channel Repeaters (DOCR) of Terrestrial-DMB (Digital Multimedia Broadcasting), there exist feedback signals generated from transmit antenna and re-entering at receive antenna. Therefore DOCR becomes unstable unless the feedback signal is properly eliminated. Previous research proposed a feedback canceller to estimate the feedback channel to deal with this problem. However formerly used estimation algorithms show unsatisfied performance in terms of convergence rate and quality although their implementations are simple. This paper applies PNLMS (Proportionate Normalized Least Mean Squares) adaptive algorithm to feedback channel estimation and evaluates the performances which solve the problem of feedback signal effectively.

• 전자공학회논문지 IE
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• v.45 no.4
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• pp.54-59
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• 2008

In this paper, circularly polarized patch antenna with 2-stage LNA for the reception of S-DMB is presented. It used teflon didelectric substrate of ${\in}_r$=2.2 and the size is $40{\times}40{\times}15\;[mm]$. Experimental results of fabricated antenna show that bandwidths of input return loss and axial ratio are about 22 [MHz] and 25 [MHz]. Input return loss, output return loss, gain, and noise figure of the fabricated 2-stage LNA are $S_{11}$=-14 [dB], $S_{22}$=-18 [dB], $S_{21}$=26.8 [dB], and NF=1.14 [dB] respectively. The fabricated active type antenna has total gain of 30.4 [dB] at 2.642 [GHz].

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.1 no.2
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• pp.91-98
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• 2008

Domestic standard for Korean T-DMB includes MPEG-4 BSAC (Bit Sliced Arithmetic Coding) audio coding that has been established in 2003. This paper presents an implementation and optimization of MPEG-4 BSAC Audio Decoder on ARM926EJ-S processor. Tools and modules of the BSAC audio decoder were implemented with 32-bit fixed point operations. Further optimization was accomplished using ARM926EJ-S Inline Assembly. The optimization was based on the total number of multiplications and MAC (Multiply and Accumulation) operations causing most of core cycles of ARM926EJ-S, and also based on analysis of ARMv5 instructions. The result of optimization was evaluated on the basis of MIPS (Million Instruction per second). Implementation results show that BSAC bitstream at 96kbps can be decoded in real-time at 65MHz CPU clocks.

• The Journal of Information Technology
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• v.8 no.4
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• pp.91-102
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• 2005

In this paper, development of embedded system based on Windows CE 5.0 which released recently is studied. Embedded softwares for the target board using S3C2410A SOC based on ARM920T core are composed of (1) BSP(Board Support Package) contains an OAL(OEM Adaptation Layer) which includes a boot loader for initializing and customizing target hardware, device drivers, and a corresponding set of configuration files (2) Windows CE 5.0 kernel (3) SDK and MP3 test application. Particularly, PB(Platform Builder) provides the efficient functions to build, test and debug the BSP and CE kernel. It is looked forward to being widely spread that Windows CE 5.0 will be utilized at smart devices such as PMP, CNS and DMB phone which inevitably require a display device.

• ETRI Journal
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• v.32 no.2
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• pp.312-318
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• 2010

A small reconfigurable patch antenna is proposed to achieve polarization diversity for digital multimedia broadcasting systems at 2.6 GHz. To obtain polarization diversity, a pair of on-slit PIN diodes is inserted in each diagonal of a cross-shaped patch. Thus, four PIN-diodes on these slits are utilized to change the connection of the slits and thus achieve polarization. Bias circuits for the diodes are allocated in the cutting corner of the cross-shaped patch to minimize the antenna size. The antenna produces left-hand circular polarization, right-hand circular polarization, or linear polarization, depending on the PIN-diode status. Analysis of circular polarization operation is explicated. Measurements show a gain of about 1.5 dB, a cross polarization of about -20 dB, and an axial ratio of about 2.5 dB.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.755-757
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• 2009

Since the research of advanced terrestrial digital multimedia broadcasting system is still in progress, and in our previous paper, in which we introduced how to combine one conventional transmitted symbol with two additional bits to form a new symbol transmission, the bit error performance of LP bits is not realizable, because even we implemented the turbo code to protect the LP bits transmission, to obtain a certain good bit error probability, the value of $E_b/N_0$ cost highly. In this paper, we modified the composition of low-priority symbol and high-priority symbol, and through the system presented in previous paper we get a better simulation result of the LP symbol transmission.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.04a
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• pp.100-102
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• 2011

스마트폰의 급속한 확산으로 모바일 디바이스를 위한 개방형 플랫폼인 안드로이드의 시장 점유율이 지속적으로 증가하고 있다. 안드로이드는 미디어 프레임워크, 카메라, Wi-Fi, GPS 등에 필요한 하위 하드웨어 드라이버만 개발하면 보다 상위 계층은 기본적으로 제공되는 라이브러리와 프레임워크를 기반으로 짧은 시간 내에 어플리케이션 개발이 가능하다. 본 논문에서는 스마트폰의 주요 서비스인 모바일 방송 어플리케이션 개발을 위한 시스템을 제안한다. 제안한 시스템은 안드로이드 소프트웨어의 계층적 스택 구조로 되어 있으며, 이를 활용한 차세대 모바일 방송 규격인 AT-DMB 수신기를 설계 및 구현하였다. 또한, 연구개발 결과물의 수신 기능을 검증하였다.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.7 no.6
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• pp.63-69
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• 2008

Reconfigurable RF one-chip solutions have been researched with the objective of designing for smaller-sized and more economical RF transceiver and it can be applied to a vehicular wireless terminal. The proposed voltage-controlled oscillator satisfies the targeted frequency range ($4.2{\sim}5.4\;GHz$) and the frequency planning which correspond to the standards such as CDMA(IS-95), PCS, GSM850, EGSM, WCDMA, WLAN, Bluetooth, WiBro, S-DMB, DSRC, GPS, and DVB-H/DMB-H/L(L Band). In order to improve phase noise performance, PMOS is adopted in the cross-coupled pair, the tail current source and MOS varactor in this VCO and differential-typed switching is proposed in capacitor array. Based on the measurement results, a total power dissipation is $5.3{\sim}6.0\;mW$ at 1.8 V power supply voltage. The oscillator is tuned from 4.05 to 5.62 GHz; The tuning range is 33%. The phase noise is -117.16 dBc/Hz at 1 MHz offset frequency and the FOM (Figure Of Merit) is $-180.84{\sim}-180.5$.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.5 s.96
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• pp.541-548
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• 2005

The research deals with the prediction and the measurement of electromagnetic wave propagation in rectangular shaped tunnels at f=2.65 GHz. The received power level was measured in the straight and the curved tunnel by using a spectrum analyzer and Satellite DMB mobile phone. Thus we have gotten the data for two cases, the straight and the curved tunnel whose radius is 300m. In addition, the prediction of wave propagation was conducted based on the ray-launching method, in same tunnel where measurement was performed. A good agreement of the measured and the predicted path loss could be confirmed. The measured path loss shows a marked difference in propagation loss: the path-loss exponent, 3.21, and 3.98, for a straight and a curved tunnel, respectively. The reason that path-loss exponent is high in a curved tunnel is that there is no direct wave but only the reflected waves, which attenuates rapidly with distance due to multiple reflections. Also the predicted path loss shows path loss exeponent, 3.2 and 3.95, for a straight and a curved tunnel which are similar to the simulation results.

• Journal of Advanced Navigation Technology
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• v.21 no.4
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• pp.402-412
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• 2017

The convergence of broadcasting and telecommunication technologies is a key issue of the ubiquitous networks. So this paper offers the convergence of integrated telecommunication networks and broadcasting system, Advanced Terrestrial Digital Multimedia Broadcasting (AT-DMB), and the interconnection of them via the Media Independent Information Server/Service (MIIS). Then, this paper proposes the fast wakeup and connection mechanism with concepts for improving QoS and energy efficiency simultaneously. In the proposed convergence network, our mechanism places the key on the minimization of both the incoming service delay destined to a turned-off interface by using the broadcasting network and the additional energy consumption. This paper further evaluates the performance of proposed mechanism through the numerical and experimental analysis and has confirmed the decrease of both service delay and energy consumption.