• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2009.10a
• /
• pp.425-427
• /
• 2009

CDMA has been used widely in communication standards like IS-95, WCDMA, and Korea-Japan Satellite-DMB. Since CDMA has a multiple access interference (MAI) problem, a CDMA receiver requires an interference cancellation scheme like prefilter, a kind of adaptive filter. This paper proposed a memory-based prefilter architecture to reduce the area of a prefilter. An adaptive filter is usually implemented with registers for area reduction, but memory-based architecture leads to a less area for a prefilter due to its functional characteristics. Experimental results show that memory-based architecture reduces the area by around 10% in common prefilters.

• Electronics and Telecommunications Trends
• /
• v.20 no.6 s.96
• /
• pp.1-14
• /
• 2005

DMB는 이동중에도 고품질 멀티미디어 방송의 시청을 가능하게 하는 새로운 디지털방송 규격으로 우리나라에서는 IT839 전략의 신 성장 산업인 디지털 TV와 함께 ‘8대서비스’ 품목에 포함되어 차세대 성장 엔진 사업으로 선정되었고 2005년 상반기에ETSI 표준으로 제정되었으며 2005년 12월 본 방송을 실시함으로써 세계 최초로 지상파 DMB 방송 시대를 눈앞에 두고 있다. 지상파 DMB 방송은 실시간 전자 상거래, 교육프로그램, 데이터 방송 서비스, TV 쇼핑, 재난 방송 등 그 활용 분야가 무궁무진하여 미래 생활의 패턴을 변화시킬 것으로 생각되고 있다. 한편 DMB 방송은 세계적으로는 유럽 노키아사의 ‘DVB-H’, 일본의 MBCo의 ‘위성 DMB’, 미국 Qualcomm사의‘MediaFLO’와 함께 세계 시장에서 경쟁하고 있다. 지상파 DMB 방송 수신을 위한 제품들은 전용 단말기 혹은 핸드폰, PDA 등에 장착되어 사용자에게 다가갈 것으로 예상되고 있으며 이를 위한 수신 칩 셋 개발 노력이 뜨겁게 이루어지고 있다. 본 고에서는 지상파 DMB를 위한 칩 셋 기술과 칩 셋 개발 동향에 대해 살펴 보고자 한다.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.30 no.5A
• /
• pp.397-401
• /
• 2005

A different alternative method for simulating bit error rate(BER) performance of Satellite Digital Multimedia Broadcasting(DMB) in tunnel environments is presented. The method based on a channel model obtained by ray-tracing is able to support BER estimation over the channel presents arbitrary statistics that are difficult to fit to an analytic expression. The BER performance for System E over the tunnel fading channel that obtained by ray-tracing is predicted by the monte-carlo method. It can be observed that the BER performance for a straight tunnel channel is better than that for a line-of-sight(LOS) area in curved tunnel. Also, the BER performance for LOS areas in a curved tunnel outperforms that for non-line-of-sight(NLOS) areas in a curved tunnel. The BER performances for straight, curved LOS and curved NLOS tunnel channels are better than that for a Rayleigh channel(K=0) and less than that for a Rician channel with K=3. Moreover, for BER=10-3, it can be seen that there is approximately a $1{\sim}1.5\;dB$ difference between those three types of tunnel channels and a Rayleigh channel.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.31 no.5A
• /
• pp.509-516
• /
• 2006

Satellite-Digital Multimedia Broadcasting(S-DMB) systems are single frequency networks which consist of a satellite and gap fillers. Though gap fillers are required to extend the coverage to NLOS(Non Line-of-Sight) area, the receiver performance can be degraded with a limited number of fingers due to the increased number of multi-paths. The paper proposes to use frequency domain equalizer(FDE) instead of conventional Rake receiver, where the guard interval is not considered in order to minimize the impact on the current S-DMB systems. Through a campaign of simulations, it is found that the proposed FDE is less sensitive to the number of gap fillers compared to the conventional Rake receiver, and can achieve a greater channel capacity in most channel environments.

• TTA Journal
• /
• s.94
• /
• pp.47-56
• /
• 2004

• TTA Journal
• /
• s.87
• /
• pp.141-148
• /
• 2003

• Korean Management Science Review
• /
• v.22 no.1
• /
• pp.179-197
• /
• 2005

This study examines market acceptance for DMB service, one of the touted new business models in Korea's next-generation mobile communications service market, using adoption end diffusion of innovation as the theoretical framework. Market acceptance for DMB service was assessed by predicting the demand for the service using the Bass model, and the demand variability over time was then analyzed by integrating the innovation adoption model proposed by Rogers (2003). In our estimation of the Bass model, we derived the coefficient of innovation and coefficient of imitation, using actual diffusion data from the mobile telephone service market. The maximum number of subscribers was estimated based on the result of a survey on satellite DMB service. Furthermore, to test the difference in diffusion pattern between mobile phone service and satellite DMB service, we reorganized the demand data along the diffusion timeline according to Rogers' innovation adoption model, using the responses by survey subjects concerning their respective projected time of adoption. The comparison of the two demand prediction models revealed that diffusion for both took place forming a classical S-curve. Concerning variability in demand for DMB service, our findings, much in agreement with Rogers' view, indicated that demand was highly variable over time and depending on the adopter group. In distinguishing adopters into different groups by time of adoption of innovation, we found that income and lifestyle (opinion leadership, novelty seeking tendency and independent decision-making) were variables with measurable impact. Among the managerial variables, price of reception device, contents type, subscription fees were the variables resulting in statistically significant differences. This study, as an attempt to measure the market acceptance for satellite DMB service, a leading next-generation mobile communications service product, stands out from related studies in that it estimates the nature and level of acceptance for specific customer categories, using theories of innovation adoption and diffusion and based on the result of a survey conducted through one-to-one interviews. The authors of this paper believe that the theoretical framework elaborated in this study and its findings can be fruitfully reused in future attempts to predict demand for new mobile communications service products.

• Broadcasting and Media Magazine
• /
• v.9 no.2
• /
• pp.13-20
• /
• 2004

위성DMB는 개인을 대상으로 하여 위성을 통해 방송콘텐츠를 송출하고 가입자는 옥외 또는 이동 중에 개인용 휴대 단말기, 휴대전화 겸용 단말기 또는 차량용 단말기를 통하여 언제 어디서나 방송 서비스를 수신할 수 있는 새로운 이용행태의 위성방송 서비스이며 기존의 방송서비스의 시간적/공간적 한계를 넘어서는 멀티미디어 서비스이다. (중략)

• Journal of Korea Multimedia Society
• /
• v.15 no.1
• /
• pp.32-39
• /
• 2012

In this paper, the implementation of location based services (LBS) using S-DMB (satellite-digital multimedia broadcasting) system was proposed. In S-DMB System, the frequency of transmitted signal is about 2 GHz which has a characteristics of strong straightness but weak diffraction so that there are many shade areas such as indoors and underground spaces. Therefore the signal transmitted from the satellite should be retransmitted by the earth repeaters called as gap filler. Because each gap filler has its own identification value, the gap filler ID introduces the area in which the gap filler was installed. Generally, the 51st data symbols of S-DMB pilot signal transmitted from the satellite are padded by dummy value and gap filler ID is embedded in this pilot symbol by the gap filler when S-DMB signals are retransmitted by gap fillers. So using gap filler ID of S-DMB system, LBS such as region registration, distance and time to destination, alarm of local area information could be implemented. In the experiment to prove the performance of the proposed LBS system using the gap filler ID of the S-DMB system, the firmware of S-DMB chip composing of RF and baseband parts was lightly modified so that application processor was able to manipulate the gap filler ID and the its related regional information.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.44 no.1
• /
• pp.93-97
• /
• 2007

In this paper a new clock generation scheme for TDM-CDM converter in the Gap Filler for satellite DMB systems has been proposed. The scheme uses the frame sync signal from the Ku band TDM receiver to lock the VCXO which provides the system clock for the TDM-CDM converter. The locking algorithm can be easily implemented in the FPGA, so that no separate circuitry is needed as in conventional PLL. With a stable OCXO, The scheme can be used to generate the reference clock to the local oscillator for RF parts.