• Title, Summary, Keyword: 에러 정정 부호

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Design of ${\gamma}$=1/3, K=9 Convolutional Codec Using Viterbi Algorithm (비터비 알고리즘을 이용한 r=1/3, K=9 콘벌루션 복부호기의 설계)

  • 송문규;원희선;박주연
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.24 no.7B
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    • pp.1393-1399
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    • 1999
  • In this paper, a VLSI design of the convolutional codec chip of code rate r=l/3, and constraint length K=9 is presented, which is able to correct errors of the received data when transmitted data is corrupted in channels. The circuit design mainly aimed for simple implementation. In the decoder, Viterbi algorithm with 3-bit soft-decision is employed. For information sequence updating and storage, the register exchange method is employed, where the register length is 5$\times$K(45 stages). The codec chip is designed using VHDL language and Design Analyzer and VHDL Simulator of Synopsys are used for simulation and synthesis. The chip is composed of ENCODER block, ALIGN block, BMC block, ACS block, SEL_MIN block and REG_EXCH block. The operation of the codec chip is verified though the logic simulations, where several error conditions are assumed. As a result of the timing simulation after synthesis, the decoding speed of 325.5Kbps is achieved, and 6,894 gates is used.

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Performance Analysis of Wireless Communication System with FSMC Model in Nakagami-m Fading Channel (Nakagami-m 페이딩 채널에서 FSMC 모델에 의한 무선 통신시스템의 성능 분석)

  • 조용범;노재성;조성준
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.8 no.5
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    • pp.1010-1019
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    • 2004
  • In this paper, we represent Nakagami-m fading channel as finite-State Markov Channel (FSMC) and analyze the performance of wireless communication system with varying the fading channel condition. In FSMC model, the received signal's SNR is divided into finite intervals and these intervals are formed into Markov chain states. Each state is modeled by a BSC and the transition probability is dependent upon the physical characterization of the channel. The steady state probability and average symbol error rate of each state and transition probability are derived by numerical analysis and FSMC model is formed with these values. We found that various fading channels can be represented with FSMC by changing state transition index. In fast fading environment in which state transition index is large, the channel can be viewed as i.i.d. channel and on the contrary, in slow fading channel where state transition index is small, the channel can be represented by simple FSMC model in which transitions occur between just adjacent states. And we applied the proposed FSMC model to analyze the coding gain of random error correcting code on various fading channels via computer simulation.

A Study on the Implementation and Performance Analysis of 900 MHz RFID System with Convolution Coding (콘벌루션 부호를 적용한 900MHz 대역 RFID 시스템 구현 및 성능 분석에 관한 연구)

  • Yun Sung-Ki;Kang Byeong-Gwon
    • Journal of the Institute of Convergence Signal Processing
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    • v.7 no.1
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    • pp.17-23
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    • 2006
  • In recent years, RFID has received much attention because of spread usage in industrial applications including factory, material flow, logistics and defense areas. However, there is only CRC-16 for error detection in ISO/IEC 18000-6 Protocols prepared for 860-960 MHz RFID, high error rates are expected in cases of high level of security and noisy envirionment. In this paper, we propose a usage of convolution code as a method for satisfying the high level of security requirement and system error performance.'1'he signal control function is implemented in a microprocessor with RF modulation and the convolutional encoding and Viterbi decoding are implemented in an FPGA chip.'The frame error rates are measured with and without convolution coding under the channel conditions of line-of- sight and non line-of-sight, respectively.

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Multi-code Bipolar Transorthogonal Code Keying with Constant Amplitude preceding (정 진폭 부호화를 사용한 다중코드 양극 Transorthgonal 변조 방식)

  • Kim, Sung-Pil;Kim, Myoung-Jin
    • Journal of The Institute of Information and Telecommunication Facilities Engineering
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    • v.3 no.2
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    • pp.61-71
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    • 2004
  • Transorthogonal 코드를 블록 단위로 확장해서 얻은 코드 집합을 적절하게 부집합으로 나누고 부호화기의 코드집합으로 할당한다. 이러한 부초화기를 병렬로 구성하고 정보 비트에 의해 선택된 부호화기의 각 출력 코드들을 합산하여 전송하는 다중코드 transorthogonal 변조 방식이 제안되어 있다. 본 논문에서는 다중코드 transorthogonal 변조 시스템의 부호화기로부터의 각 출력 코드를 또 다른 정보 비트로 이진 위상 변조한 후 합산하여 전송하는 시스템을 제안한다. 다중코드 transorthogonal 변조 시스템에서 적용된 정 진폭 부호화 알고리즘과정 전폭 부호화에 사용된 잉여비트를 이용한 수신 에러 정정 알고리즘을 제안된 시스템에 수정 없이 적용할 수 있으며 다중코드 transorthogonal 변조 방식에 비해 대역폭 효율이 개선됨을 보인다.

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Architecture Design of Turbo Codec using on-the-fly interleaving (On-the-fly 인터리빙 방식의 터보코덱의 아키텍쳐 설계)

  • Lee, Sung-Gyu;Song, Na-Gun;Kay, Yong-Chul
    • The KIPS Transactions:PartC
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    • v.10C no.2
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    • pp.233-240
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    • 2003
  • In this paper, an improved architecture of turbo codec for IMT-2000 is proposed. The encoder consists of an interleaver using an on-the-fly type address generator and a modified shift register instead of an external RAM, and the decoder uses a decreased number of RAM. The proposed architecture is simulated with C/VHDL languages, where BER (bit-error-rate) performances are generally in agreement with previous data by varying interaction numbers, interleaver block sizes and code rates.

Transmission performance Improvement of Wireless ATM Cell in Fading Channel (페이딩 채널에서 무선 ATM 셀전송 성능개선에 관한 연구)

  • Chung, Boo-Young;Park, Ki-Sik;Kang, Young-Heung;Cho, Sung-Joon;Lee, Jin
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.9 no.2
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    • pp.179-190
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    • 1998
  • One of the most important topics of recent years is that a multimedia technology such as wireless ATM has been introduced in radio systems for video, voice and data transmission. A major problem in such systems is the occurrence of errors due to multipath fading or interference. To combat this problem, forward error correction (FEC) coding is commonly used as a means of eliminating these errors. This paper has analyzed theoretically the effect of fading to design effective wireless ATM system. The BER, CLR, and CER of wireless ATM system adopting FEC coding and diversity reception techniques have been derived in fading environment. Also, simulations of BER and CLR have been carried out and compared with the above theoretical results.

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Cell to Cell Interference Cancellation Algorithms in Multi level cell Flash memeory (MLC 플래시 메모리에서의 셀간 간섭 제거 알고리즘)

  • Jeon, Myeong-Woon;Kim, Kyung-Chul;Shin, Beom-Ju;Lee, Jung-Woo
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.47 no.12
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    • pp.8-16
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    • 2010
  • NAND multilevel cell (MLC) flash memory is widely issued because it can increase the capability of storage by storing two or more bits to a single cell. However if a number of levels in a cell increases, some physical features like cell to cell interference result cell voltage shift and it is known that a VT shift is unidirectional. To reduce errors by the effects, we can consider error correcting codes(ECC) or signal processing methods. We focus signal processing methods for the cell to cell interference voltage shift effects and propose the algorithms which reduce the effects of the voltage shift by estimating it and making level read voltages be adaptive. These new algorithms can be applied with ECC at the same time, therefore these algorithms are efficient for MLC error correcting ability. We show the bit error rate simulation results of the algorithms and compare the performance of the algorithms.

Analysis of Viterbi Algorithm for Low-power Wireless Sensor Network (저전력 무선 센서네트워크를 위한 비터비 알고리즘의 적용 및 분석)

  • Park, Woo-Jun;Kim, Keon-Wook
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.44 no.6
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    • pp.1-8
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    • 2007
  • In wireless sensor network which uses limited battery, power consumption is very important factor for the survivality of the system. By using low-power communication to reduce power consumption, error rate is increased in typical conditions. This paper analyzes power consumption of specific error control coding (ECC) implementations. With identical link quality, ECC provides coding gain which save the power for transmission at the cost of computing power. In sensor node, transmit power is higher than computing power of Micro Controller Unit (MCU). In this paper, Viterbi algerian is applied to the low-transmit-power sensor networks in terms of network power consumption. Practically, Viterbi algorithm presents 20% of reduction of re-transmission in compared with Auto Repeat Request (ARQ) system. Furthermore, it is observed that network power consumption is decreased by almost 18%.

A Study on the Reliability Improvement of RFID System (REID 시스템의 신뢰성 향상에 관한 연구)

  • Ham, Jung-Ki;Lee, Cheong-Jin;Kwon, Oh-Heung
    • Journal of Digital Contents Society
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    • v.7 no.3
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    • pp.169-174
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    • 2006
  • In recent years, RFID is widely used in industrial applications including factory, material flow, logistics and defense areas. In this paper, The convolutional encoding and viterbi decoding is also implemented to improve the system performance. in an FPGA chip. The used convolution code is constraint length K=3 and rate R=1/2. The length of command frame and response frame is total of 48bits consisting of SOF 8 bits, command 16 bits, CRC 16 bit, and EOF 8 bits. And also the frame error rates are measured under the channel of line-of-sight and non line-of-sight, respectively. The performances are analyzed with FSK modulation only and FSK modulation added with convolutional encoding. These two measured results are compared with that of a RFID system with ASK modulation.

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A Study on the Reliability Improvement of RFID System (RFID System의 신뢰성 향상에 관한 연구)

  • Ham Jung-Gi;Kwon Oh-Heung
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • pp.542-545
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    • 2006
  • In recent years, RFID is widely used in Industrial applications including factory, material flow, logistics and defense areas. In this paper, we developed a RFID baseband system with ASK modulation and convolutional channel code. A commercial ASK RF module is used and its frequency range in $350\sim351MHz$ and power is 10mW and the convolution code is constraint length k=3 and rate R=1/2. The performance is measured by frame error rate and the convolutional code is very useful in performance improvement and, also we implemented the binary search algorithm as anti-collision method and we show the wave shapes whit collision occurrence. This RFID system is designed by FPGA therefore it produces result of speed-up and improvement of reliability.

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