• Title, Summary, Keyword: error protection

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Unequal Error Protection and Error Concealment Schemes for the Transmission of H.263 Video over Mobile Channels

  • Hong, Won-Gi;Ko, Sung-Jea
    • Journal of IKEEE
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    • v.2 no.2
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    • pp.285-293
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    • 1998
  • This paper presents unequal error protection and error concealment techniques far robust H.263 video transmission over mobile channels. The proposed error protection scheme has three major features. First, it has the capability of preventing the loss of synchronization information in H.263 video stream as much as possible that the H.263 decoder can resynchronize at the next decoding point, if errors are occurred. Secondly, it employs an unequal error protection scheme to support variable coding rates using rate compatible punctured convolutional (RCPC) codes, dividing the encoded stream into two classes. Finally, a macroblock-interleaving scheme is employed in order to minimize the corruption of consecutive macroblocks due to burst errors, which can make a proper condition for error concealment. In addition, to minimize the spatial error propagations due to the variable length codes, a fast resynchronization scheme at the group of block layer is developed for recovering subsequent error-free macroblocks following the damaged macroblock. futhermore, error concealment techniques based on both side match criterion and overlapped block motion compensation (OBMC) are employed at the source decoder so that it can not only recover the lost macroblock more accurately, but also reduce blocking artifacts. Experimental results show that the proposed scheme can be an effective error protection scheme since proper video quality can be maintained under various channel bit error rates.

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Design of Unequal Error Protection for MIMO-OFDM Systems with Hierarchical Signal Constellations

  • Noh, Yu-Jin;Lee, Heun-Chul;Lee, Won-Jun;Lee, In-Kyu
    • Journal of Communications and Networks
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    • v.9 no.2
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    • pp.167-176
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    • 2007
  • In multimedia communication systems, efficient transmission system design should incorporate the use of matching unequal error protection (UEP), since source coders exhibit unequal bit error sensitivity. In this paper, we present UEP schemes which exploit differences in bit error protection levels in orthogonal frequency division multiplexing (OFDM) systems over frequency selective fading channels. We introduce an UEP scheme which improves the link performance with multiple transmit and receive antennas. Especially, we propose a new receiver structure based on two stage Maximum Likelihood detection (MLD) schemes which can approach the performance of a full search MLD receiver with much reduced computational complexity. In the performance analysis, we derive a generalized pairwise error probability expression for the proposed UEP schemes. Simulation results show that the proposed schemes achieve a significant performance gain over the conventional equal error protection (EEP) scheme.

UEP Effect Analysis of LDPC Codes for High-Quality Communication Systems (고품질 통신 시스템을 위한 LDPC 부호의 UEP 성능 분석)

  • Yu, Seog Kun;Joo, Eon Kyeong
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.38A no.6
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    • pp.471-478
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    • 2013
  • Powerful error control and increase in the number of bits per symbol should be provided for future high-quality communication systems. Each message bit may have different importance in multimedia data. Hence, UEP(unequal error protection) may be more efficient than EEP(equal error protection) in such cases. And the LDPC(low-density parity-check) code shows near Shannon limit error correcting performance. Therefore, the effect of UEP with LDPC codes is analyzed for high-quality message data in this paper. The relationship among MSE(mean square error), BER(bit error rate) and the number of bits per symbol is analyzed theoretically. Then, total message bits in a symbol are classified into two groups according to importance to prove the relationship by simulation. And the UEP performance is obtained by simulation according to the number of message bits in each group with the constraint of a fixed total code rate and codeword length. As results, the effect of UEP with the LDPC codes is analyzed by MSE according to the number of bits per symbol, the ratio of the message bits, and protection level of the classified groups.

Hierarchical channel coding scheme Using Unequal Error Protection (Unequal Error Protection 이용한 계층적 부호화 방식)

  • 정지원;최은아;박상진;이인기;김내수
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.29 no.4C
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    • pp.454-460
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    • 2004
  • In this paper, we studied hierarchical channel coding scheme using unequal error protection method for consecutively broadcastingservice under the rain attenuation of Ka band satellite broadcasting. Unlike time-sharing methods, which are design for different channel coding scheme in according to different modulation, unequal error protection method is made in such way that minimum distance between signals are different for importance of signals with same modulation. Consequently we proposed optimal method according to performance analysis.

Performance Optimization of Tandem Source-Channel Coding Systems Employing Unequal Error Protection Under Complexity Constraints (복잡도 제한 하에서 비균등 오류 보호 기법을 사용하는 탠덤 소스-채널 코딩 시스템의 성능 최적화)

  • Lim, Jongtae
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.18 no.10
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    • pp.2537-2543
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    • 2014
  • Between tandem source-channel coding systems and joint source-channel coding systems, it has been known that there is a complexity threshold in complexity versus performance. In this paper, by expanding the previous analysis for equal error protection systems, we analyze and compare the performance under complexity constrains for tandem source-channel coding systems which employ unequal error protection. Under a given complexity constraint, the optimization is performed to minimize the end-to-end distortion of each representative tandem and joint source-channel coding system. The results show that the complexity threshold for unequal error protection systems becomes smaller and the performance enhancement of unequal error protection systems over equal error protection systems gets smaller as the system complexity gets larger.

An Efficient UEP Transmission Scheme for MIMO-OFDM Systems (MIMO-OFDM 시스템을 위한 효율적인 UEP 전송기법 제안)

  • Lee, Heun-Chul;Lee, Byeong-Si;Sundberg, Carl-Erik W.;Lee, In-Kyu
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.32 no.5C
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    • pp.469-477
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    • 2007
  • Most multimedia source coders exhibit unequal bit error sensitivity. Efficient transmission system design should therefore incorporate the use of matching unequal error protection (UEP). In this paper, we present and evaluate a flexible space-time coding system with unequal error protection. Multiple transmit and receive antennas and bit-interleaved coded modulation techniques are used combined with rate compatible punctured convolutional codes. A near optimum iterative receiver is employed with a multiple-in multiple-out inverse mapper and a MAP decoder as component decoders. We illustrate how the UEP system gain can be achieved either as a power or bandwidth gain compared to the equal error protection system (EEP) for the identical source and equal overall quality for both the UEP and EEP systems. An example with two/three transmit and two receive antennas using BPSK modulation is given for the block fading channel.

Unequal Error Protection for the Wireless ATM with Turbo Coding (무선 ATM에서 터보코딩을 사용한 UEP)

  • 문병현
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.26 no.8A
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    • pp.1322-1328
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    • 2001
  • 본 논문에서는 무선 ATM 환경에서 터보코딩을 이용한 UEP(Unequal Error Protection)을 제안한다. 일반적으로 ATM셀의 header 부분은 payload 부분보다 중요시되며 header 부분에 payload 보다 부호율이 낮은 터보코드를 무선 ATM 적용하여 비트오류확률과 셀손실 확률을 구하였다. 무선 ATM 환경에서 터보코드를 사용하고 프레임길이 28바이트의 DLC 셀구조에서 UEP가 가능함을 보였다. 부호율 1/3인 터보 코딩을 이용한 경우 동일한 부호율의 컨벌루션 코드를 이용한 EEP(Equal Error Protection)과 비교하여 비트 오류확률과 셀 손실율에 있어서 최소 1dB와 2dB 신호대잡음비의 개선을 보였다.

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Design of A Downlink Power Control Scheme in Unequal Error Protection Multi-Code CDMA Mobile Medicine System

  • Lin, Chin-Feng;Lee, Hsin-Wang;Hung, Shih-Ii;Li, Ching-Yi
    • Proceedings of the Korea Society of Information Technology Applications Conference
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    • pp.335-338
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    • 2005
  • In this paper, we propose a downlink power control scheme to apply in the unequal error protection multi-code CDMA mobile medicine system. The mobile medicine system contains (i) blood pressure and body temperature measurement value, (ii) ECG medical signals measured by the electrocardiogram device, (iii) mobile patient's history, (iv) G.729 audio signal, MPEG-4 CCD sensor video signal, and JPEG2000 medical image. By the help of the multi-code CDMA spread spectrum communication system with downlink power control scheme and unequal error protection strategy, it is possible to transmit mobile medicine media and meet the quality of service. Numerical analysis and simulation results show that the system is a well transmission platform in mobile medicine.

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Priority-based Unequal Error Protection Scheme of Data partitioned H.264 video with Hierarchical QAM

  • Chen, Rui;Wu, Minghu;Yang, Jie;Rui, Xiongli
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.8 no.11
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    • pp.4189-4202
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    • 2014
  • In this paper, we propose a priority-based unequal error protection scheme of data partitioned H.264/AVC video with hierarchical quadrature amplitude modulation. In order to map data with higher priority onto the most significant bits of QAM constellation points, a priority sorting method categorizes different data partitions according to the unequal importance factor of encoded video data in one group of pictures by evaluated the average distortion. Then we propose a hierarchical quadrature amplitude modulation arrangement with adaptive constellation distances, which takes into account the unequal importance of encoded video data and the channel status. Simulation results show that the proposed scheme improves the received video quality by about 2 dB in PSNR comparing with the state-of-the-art unequal error protection scheme, and outperforms EEP scheme by up to 5 dB when the average channel SNR is low.

Protection Algorithm for Error Prone Bit Positions of Turbo Codes (터보 부호의 오류 취약 비트 보완 알고리듬)

  • Wangrok Oh;Kyungwhoon Cheun;Kim, Jinwoo;Kyeongcheol Yang
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.29 no.7A
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    • pp.775-780
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    • 2004
  • In this paper, we propose a simple protection scheme for error prone bit positions of turbo codes using the error detection capability of the CRC, which is almost always employed in practical systems. The proposed scheme based on bit flipping with CRC offers flexibility on selecting the level of protection. Also, not having send additional parity bits or discarding useful bit positions, it offers the best error performance for a given level of protection.