• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.3
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• pp.45-55
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• 2000

DAB(Digital Audio Broadcasting)는 기존 아날로 그 방식 AM과 FM 라디오 방송의 한계와 문제점을 극복하고 CD 수준 음질의 오디오를 포함한 다양한 멀티미디어 서비스를 제공하는 차세대 라디오 방송이다. DAB는 전송 주파수 대역에 따라 기존의 FM/AM 대역과 다른 새로운 대역을 사용하는 Out-of-Band 방식과 기존의 FM/AM 대역을 사용하는 In-Band 방식으로 분류할 수 있다. Out-of-Band 방식으로는 유럽의 Eureka-147과 일본의 협대역 ISDB-T(Integrated Services Digital Broadcasting-Terrestrial) 방식이 있으며, In-Band 방식은 미국의 USADR(USA Digital Radio)사와 LDR(Lucent Digital Radio)사가 개발하고 있는 IBOC(In-Band On Channel) 방식과 국내 한국전자통신연구원(ETRI)에서 개발 중인 IBAC(In-Band Adjacent Channel) 방식이 있다. 본 고에서는 DAB의 전송 주파수 대역에 따른 방식별 특성을 고찰하고 유럽, 일본, 미국과 국내에서 상용화 서비스 또는 개발되고 있는 DAB 시스템의 기술동향을 분석 한다.

• Broadcasting and Media Magazine
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• v.1 no.3
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• pp.16-29
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• 1996

본 논문에서는 지상망 디지털 오디오방송(DAB) 시스템의 출현 배경과 미국 내에서 DAB 시스템의 개발과 성능시험 평가를 위한 NAB, NRSC, EIA, FCC, NASA, Lewis 연구소, 카나다 CRC의 활동상을 소개한다. 구체적으로는 미국에서 개발 중에 있는 USA Digital Radio사, Amati Communications사와 Kintel Technologies사의 FM In-Band On-Channel(IBOC)방식, AT＆T사의 FM In-Band Adjacent-Channel(IBAC)방식과 USA Digital Radio사의 AM IBOC 방식의 원리와 특성, 핵심기술, 개발현황, 성능시험 결과와 각 방식의 장단점을 비교 분석하며 또한 미국의 In-Band 방식과 유럽의 Eureka 147 New-Band 방식을 비교 분석한다.

• Journal of Broadcast Engineering
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• v.17 no.6
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• pp.990-1003
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• 2012

In this paper, the possibility and necessity of the digital broadcasting propulsion in AM and FM is presented based on DRM and DRM+ transmission modes, They are the members of series technological family in digital radio development. As the frequency utilization, the application of DRM+ is flexible in any mode such as IN-BAND or OUT-OF-BAND. When the digital audio broadcasting is planned at LOW-VHF bandwidth such as TV channel No.5 and NO.6 being adjacent to FM band and OUT-Of-BAND DRM+ technology is applied, there is no collision and jamming. Particularly, in the IN-BAND Hybrid mode, it is mentioned that there was the difficulty problem for multiple SFN transmitters uses. Not like the IN-BAND mode the OUT-OF-BAND mode lets multiple transmitters, because neighbor transmitters do not interfere each other. Digital transmitter can be combined with the existing FM transmitter. The intensity of power and size of area can be easily determined according to local broadcasters' condition. And the OUT-OF-BAND mode is advantageous for AM/FM integration in digital radio receiver manufacturing, which makes the conversion schedule much shorter.

• Journal of Broadcast Engineering
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• v.8 no.2
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• pp.181-197
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• 2003

Notion Compensation(MC) technique using Sub-Band Coding with the hierarchical structure is efficient to estimate real motion. In the hierarchical pyramid method, low-band MC pyramid method is popular, where the upper layer estimate the glover motion and next lower layer estimate the local motion. The low-band MC pyramid scheme has two problems. First, because the quantization errors at lower layer are accumulated when using coding and quantizing, it is impossible to search the exact Motion Vector(MV) Second, because of the top-down search problem in the hierarchical structure, MV mismatch in upper layer causes serious MV in lower layer So. we propose new hierarchical MC pyramid method based on edge classification. In this Paper, we show that the performance of proposed Pass-band motion compensation pyramid technique is better than low-band motion compensation pyramid. Also, in the pyramid motion estimation, we propose initial MV estimation scheme based on the edge-pattern classification. As a result, we find that PSNR was increased.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.5
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• pp.501-509
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• 2011

Software defined radio(SDR) has a goal that places the analog-to-digital converter(ADC) as near the antenna as possible. But current technique actually can't do analog-to-digital converting about RF band signals. So one method is studying that samples RF band signals to IF band. One of the ways Sub-Sampling technique can convert signals from RF band to IF band without oscillator. If Sub-Sampling technique is used, over 2 bands can convert signals from RF band to IF band. But due to the filter performance in RF band, it is possible to generate interference between signals that is converted in low frequency band. The effect degrades performance. In this paper, we propose one method that uses time division multiplexing(TDM) method as a solution to avoid interference between signals. By doing TDM and Sub-Sampling at the same time that method can get signals without large changes of structures.

• Journal of Satellite, Information and Communications
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• v.5 no.1
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• pp.32-37
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• 2010

The algorithm of multiple channel signal processing requires the flexibility of variable frequency band, efficient allocation of transmission power, and flexible frequency band reallocation to satisfy various service types which requires different transmission rates and frequency band. There are three methods including per-channel approach, multiple tree approach, and block approach performing frequency band reallocation method by channelization and dechannelization in the multiple-channel signal. This paper proposes an improved per-channel approach for converting the frequency band of multiple carrier signals efficiently. The proposed algorithm performs decimation and interpolation using CIC(cascaded integrator comb filter), half-band filter, and FIR filter. In addition, it performs filtering of each sub-channel, and reallocates channel band through FIR low-pass filter in the multiple-channel signal. The computer simulation result shows that the perfect reconstruction of output signal and the flexible frequency band reallocation is performed efficiently by the proposed algorithm.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.6B
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• pp.403-410
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• 2008

In this paper, we investigate the performance of MMR system in Non-transparent mode. The IEEE 802.16j MMR system has two node of operation, Single-frame (in band) and Multi-frame (out band) mode. In the analysis, we assume that channel interference between MR-BS and RS, or between RSs anywhere in the given area is ignored. The performance is presented in terms of the delay and the frame efficiency by varying number of RS and BS coverage to RS coverage ratio and the maximum coverage area of a BS by varying traffic density. Analytical results show that the Single-frame is more efficient than Multi-frame in frame efficiency and coverage extension.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.8
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• pp.15-20
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• 2013

In narrowband communication systems operating in VHF and UHF bands, the performance degradation due to a frequency offset is inevitable. In this paper, we propose a frequency offset reduction scheme using the dual-band FSK modulation for narrowband communications. The proposed scheme not only offer a relatively reliable performance under a severe frequency offsets, but also can obtain a frequency diversity gain in Rayleigh fading channel.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.1
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• pp.60-67
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• 2002

In this paper, the dual band VCO of mobile communication terminal using oscillation part switching circuit is proposed. In order to model the VCO accurately, the resonator is converted the equivalent circuit which is analyzed to use numerical method and designed optimal the dual band VCO operating GSM and DCS band. In order to demonstrate the objective theory of the proposed VCO, the dual band VCO is designed and experimented. The results of experiment, it is conformed that the VCO can be used mobile communication hand phone and components of three generation mobile communication systems.

• The KIPS Transactions:PartC
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• v.8C no.4
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• pp.443-450
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• 2001

본 논문에서는 무선 ATM 망에서 VBR(Variable Bit Rate) 트래픽의 QoS(Quality of Service)를 보장하고 무선 채널의 효율성을 극대화 할 수 있는 새로운 동적 슬롯 할당 알고리즘인 NDSA(Neural Dynamic Slot Assignment)를 제안한다. 제안된 알고리즘에서는 ATM 셀 헤더 부분의 GFC(Generic Flow Control) 필드 상에 단말기의 버퍼 상태와 셀 발생률 변화를 부호화 하여 piggybacking 하는 in-band 방식을 채택하였으며 다음 프레임에 할당할 슬롯의 갯수를 기존 방식과는 달리 신경회로망을 이용하여 유동적으로 조절하여 할당함으로써 단말기의 셀 손실이나 지연에 대한 QoS를 보장하고 채널 이용 효율을 높일 수 있었다. 제안된 알고리즘은 BONeS tool을 이용한 시뮬레이션을 통하여 기존의 방식과 비교 분석한 결과 그 정당성을 확인하였다.