• Title, Summary, Keyword: 비트율 제어

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A Simple Multi-rate Parallel Interference Canceller for the IMT-2000 3GPP System (IMT-2000 3GPP 시스템을 위한 간단한 다중 전송률 병렬형 간섭제거기)

  • Kim, Jin-Kyeom;Oh, Seong-Keun;Sunwoo, Myung-Hoon
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.38 no.12
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    • pp.10-19
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    • 2001
  • In this paper, we propose an effective but simple multi-rate parallel interference canceller(PIC) for the international mobile telecommunications-2000(IMT-2000) 3rd generation partnership project (3GPP) system. For effective multi-rate processing, we define the basic block as one symbol period of the dedicated physical control channel(DPCCH) having the lowest data rate and common to all users. Then, decision and interference cancellation are performed at every basic block. For an asynchronous channel, we propose an advance removal scheme that removes in advance multiple access interference(MAI) due to the next blockof other users with shorter delay. Introducing a pipeline structure at a sample base, we can implement efficiently the PIC using the advance removal scheme with a minimum hardware and no extra computations. Through computer simulations, we analyze the bit error rate(BER) performance of the proposed PIC with respect to signal-to-noise ratio(SNR) and the number of users.

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Performance Analysis of Optical CDMA System with Cross-Layer Concept (계층간 교차 개념을 적용한 광 부호분할 다중접속 시스템의 성능 분석)

  • Kim, Jin-Young;Kim, Eun-Cheol
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.46 no.7
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    • pp.13-23
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    • 2009
  • In this paper, the network performance of a turbo coded optical code division multiple access (CDMA) system with cross-layer, which is between physical and network layers, concept is analyzed and simulated. We consider physical and MAC layers in a cross-layer concept. An intensity-modulated/direct-detection (IM/DD) optical system employing pulse position modulation (PPM) is considered. In order to increase the system performance, turbo codes composed of parallel concatenated convolutional codes (PCCCs) is utilized. The network performance is evaluated in terms of bit error probability (BEP). From the simulation results, it is demonstrated that turbo coding offers considerable coding gain with reasonable encoding and decoding complexity. Also, it is confirmed that the performance of such an optical CDMA network can be substantially improved by increasing e interleaver length and e number of iterations in e decoding process. The results of this paper can be applied to implement the indoor optical wireless LANs.

Automatic Tuning Architecture of RC Time-Constant due to the Variation of Integrated Passive Components (집적된 수동 소자 변동에 의한 RC 시상수 자동 보정 기법)

  • Lee, Sung-Dae;Hong, Kuk-Tae;Jang, Myung-Jun;Chung, Kang-Min
    • Journal of Sensor Science and Technology
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    • v.6 no.2
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    • pp.115-122
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    • 1997
  • In this paper, on-chp atomatic tuning circuit, using proposed integration level approximation technique, is designed to tuning of the variation of RC time-constant due to aging or temperature variation, etc. This circuit reduces the error, the difference between code values and real outputs of integrator, which is drawback of presented dual-slope tuning circuit and eliminates modulations of processing signals in integrated circuit due to fixed tuning codes during ordinary operation. This system is made up of simple integrator, A/D converter and digital control circuit and all capacitors are replaced by programed capacitor arrays in this system. This tuning circuit with 4 bit resolution achieves $-9.74{\sim}+9.68%$ of RC time constant error for 50% resistance variation.

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An Exact BER Analysis of Dual-Hop MIMO Decouple-and-Forward Relaying with Orthogonal Space-Time Block Codes (직교 시공간 블록 부호를 적용한 듀얼 홉 MIMO Decouple-and-Forward 릴레이에 대한 정확한 비트 에러율 분석)

  • Lee, Jae-Hoon;Kim, Dong-Woo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.33 no.12A
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    • pp.1147-1155
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    • 2008
  • In this paper, we derive the probability density function (PDF) of end-to-end signal-to-noise ratio (SNR) for t he dual-hop MIMO (Multiple-Input Multiple-Output) DCF (Decouple-and-Forward) system. We also provide the end-to-end bit error ratio (BER) with M-ary PSK constellations for four antenna combinations. These are (1,8,1), (8,1,8), (2,4,2), and (4,2,4). Each number in the parentheses is the number of the transmit antenna at the source, the transmit and receive antenna at the relay and the receive antenna at the destination, respectively. We show t hat the end-to-end BER expression with M-ary PSK constellations makes an exact match with numerical results. We also show that MIMO DCF relay system achieves spatial diversity.

Multi Channel UWB Data Transmission System for Multimedia Communication (멀티미디어 통신을 위한 다채널 UWB 데이터 전송 시스템)

  • Noh, Jin-Soo;Rhee, Kang-Hyeon
    • Journal of the Institute of Electronics Engineers of Korea CI
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    • v.42 no.6
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    • pp.101-108
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    • 2005
  • In this paper, we proposed a new algorithm of pulse generation and detection for the UWB multimedia communication system. The existing UWB systems using Gaussian pulse have some difficulties to cope with bandwidth limitation and frequency transition. In this paper, we introduce a new pulse generation method, which is able to control the bandwidth and center frequency that applies to the frequency modulation method, thus the proposed algorithm could improve the detection performance of receiving. And we proposed the multi channel transmission algorithm which transmits 1 channel synthesized at same time using the wavelet synthesis filter. Because of wavelet filter's perfect reconstruction property, the BER(Bit Error Rate) of transmission data is not changed by the number of accessed user. BER is changed only the property of channel transmission. By the results of simulation, when shift SNR from 2dB to 8dB on AWGN channel, we confirmed that the proposed algerian has $3.9063{\times}10^{-4}$ BER at 4dB SNR(AWGN channel).

Efficient Channel Scheduling Technique Using Release Time Unscheduled Channel Algorithm in OBS WDM Networks (OBS WDM 망에서 비 할당된 채널 개방시간을 이용한 효율적인 채널 스케줄링 기법)

  • Cho Seok-man;Kim Sun-myeng;Choi Dug-kyoo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.30 no.10A
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    • pp.912-921
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    • 2005
  • Optical burst switching(OBS) is a promising solution for building terabit optical routers and realizing If over WDM. Channel scheduling Algorithm for reduce contention is one of the major challenges in OBS. We address the issue of how to provide basic burst channel scheduling in optical burst switched WDM networks with fiber delay lines(FDLs). In OBS networks the control and payload components or a burst are sent separately with a time gap. If CHP arrives to burst switch node, because using scheduling algorithm for data burst, reservation resources such as wavelength and transmit data burst without O/E/O conversion, because contention and void between burst are happened at channel scheduling process for data burst that happened the link utilization and bust drop probability Existent proposed methods are become much research to solve these problems. Propose channel scheduling algorithm that use Release Time of bust to emphasize clearance between data and data dissipation that is happened in data assignment in this treatise and maximize bust drop probability and the resources use rate (RTUC : Release Time Unscheduled Channel). As simulation results, Confirmed that is more superior in terms of data drop and link utilization than scheduling algorithm that is proposed existing. As simulation results, confirmed improved performance than scheduling algorithm that is proposed existing in terms of survival of burst, efficiency resource and delay. However, In case load were less, degradation confirmed than existent scheduling algorithm relatively, and confirmed that is superior in data drop aspect in case of load increased.

A Study on The Design of China DSRC System SoC (중국형 DSRC 시스템 SoC 설계에 대한 연구)

  • Shin, Dae-Kyo;Choi, Jong-Chan;Lim, Ki-Taeg;Lee, Je-Hyun
    • 전자공학회논문지 IE
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    • v.46 no.4
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    • pp.1-7
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    • 2009
  • The final goal of ITS and ETC will be to improve the traffic efficiency and mobile safety without new road construction. DSRC system is emerging nowadays as a solution of them. China DSRC standard which was released in May 2007 has low bit rate, short message and simple MAC control. The DSRC system users want a long lifetime over 1 year with just one battery. In this paper, we propose the SoC of very low power consumption architecture. Several digital logic concept and analog power control logics were used for very low power consumption. The SoC operation mode and clock speed, operation voltage range, wakeup signal detector, analog comparator and Internal Voltage Regulator & External Power Switch were designed. We confirmed that the SoC power consumption is under 8.5mA@20Mhz, 0.9mA@1Mhz in active mode, and under 5uA in power down mode, by computer simulation. The design of SoC was finished on Aug. 2008, and fabricated on Nov. 2008 with $0.18{\mu}m$ CMOS process.

The Design of Single Phase PFC using a DSP (DSP를 이용한 단상 PFC의 설계)

  • Yang, Oh
    • Journal of the Institute of Electronics Engineers of Korea SC
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    • v.44 no.6
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    • pp.57-65
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    • 2007
  • This paper presents the design of single phase PFC(Power Factor Correction) using a DSP(TMS320F2812). In order to realize the proposed boost PFC converter in average current mode control, the DSP requires the A/D sampling values for a line input voltage, a inductor current, and the output voltage of the converter. Because of a FET switching noise, these sampling values contain a high frequency noise and switching ripple. The solution of A/D sampling keeps away from the switching point. Because the PWM duty is changed from 5% to 95%, we can#t decide a fixed sampling time. In this paper, the three A/D converters of the DSP are started using the prediction algorithm for the FET ON/OFF time at every sampling cycle(40 KHz). Implemented A/D sampling algorithm with only one timer of the DSP is very simple and gives the autostart of these A/D converters. From the experimental result, it was shown that the power factor was about 0.99 at wide input voltage, and the output ripple voltage was smaller than 5 Vpp at 80 Vdc output. Finally the parameters and gains of PI controllers are controlled by serial communication with Windows Xp based PC. Also it was shown that the implemented PFC converter can achieve the feasibility and the usefulness.

Motion Estimation Skipping Technique for Fast Motion Estimation (고속 움직임 추정을 위한 움직임 추정 생략 기법)

  • 강현수;박성모
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.28 no.7C
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    • pp.726-732
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    • 2003
  • The paper proposes a motion estimation (ME) technique to reduce computational complexity. It is achieved by skipping ME process for macro-blocks decided to be in no need of the operation. Thus, it is called ME skipping technique(MEST). In general, the ME is composed of integer pixel precision ME (IME) followed by half pixel precision ME (HME). The MEST is performed just before an IME process and makes a decision on skipping the IME process according to a criterion based on ME errors of adjacent macro-blocks (MBs) already encoded. When the IME process for a MB is decided to be skipped, which is called ME skip mode, the IME process is skipped and the integer pixel precision motion vector of the MB is just replaced by a predicted vector and used as the input of HME. On the other hands, the IME processes for MBs in ME non-skip mode are not skipped but normally performed. Accordingly, the MEST is very effective to reduce computational complexity when MBs in ME skip mode is abundant. In addition, when the MEST is applied to video encoder, it contributes to more accurate rate control and more robusaess for channel errors. It is experimentally shown that the MEST has the above advantages while maintaining good reconstructed image quality.