The Experts below are selected from a list of 26850 Experts worldwide ranked by ideXlab platform

Shashidhar Vishwanath - One of the best experts on this subject based on the ideXlab platform.

  • opportunistic relay selection with limited feedback
    Vehicular Technology Conference, 2007
    Co-Authors: C.k. Lo, W Heath, Shashidhar Vishwanath
    Abstract:

    It has been shown that a decentralized relay selection protocol based on opportunistic feedback from the relays yields good throughput performance in dense wireless networks. This selection strategy supports a hybrid-ARQ transmission approach where relays forward Parity Information to the destination in the event of a decoding error. Such an approach, however, suffers a loss compared to centralized strategies that select relays with the best channel gain to the destination. This paper closes the performance gap by adding another level of channel feedback to the decentralized relay selection problem. It is demonstrated that only one additional bit of feedback is necessary for good throughput performance. The performance impact of varying key parameters such as the number of relays and the channel feedback threshold is discussed. An accompanying bit error rate analysis demonstrates the importance of relay selection

  • VTC Spring - Opportunistic Relay Selection with Limited Feedback
    2007 IEEE 65th Vehicular Technology Conference - VTC2007-Spring, 2007
    Co-Authors: W Heath, Shashidhar Vishwanath
    Abstract:

    It has been shown that a decentralized relay selection protocol based on opportunistic feedback from the relays yields good throughput performance in dense wireless networks. This selection strategy supports a hybrid-ARQ transmission approach where relays forward Parity Information to the destination in the event of a decoding error. Such an approach, however, suffers a loss compared to centralized strategies that select relays with the best channel gain to the destination. This paper closes the performance gap by adding another level of channel feedback to the decentralized relay selection problem. It is demonstrated that only one additional bit of feedback is necessary for good throughput performance. The performance impact of varying key parameters such as the number of relays and the channel feedback threshold is discussed. An accompanying bit error rate analysis demonstrates the importance of relay selection

A. Aydin Alatan - One of the best experts on this subject based on the ideXlab platform.

  • Error detection and concealment for video transmission using Information hiding
    Signal Processing: Image Communication, 2008
    Co-Authors: Ayhan Yılmaz, A. Aydin Alatan
    Abstract:

    Video transmission over noisy channels makes error concealment an indispensable job. Utilization of data hiding for this problem provides a reserve Information about the content at the receiver, while unchanging the transmitted bit-stream syntax; hence, improves the reconstructed video quality with almost no extra channel utilization. A spatial domain error concealment technique, which hides edge orientation Information of a block, and a resynchronization technique, which embeds bit-length of a block into other blocks are composed. The proposed method also exploits these two techniques for detecting errors via some extra Parity Information. Moreover, the motion vectors between consecutive frames are also embedded into the consecutive frames for better concealment at the receiver. Finally, as a novel approach, the bit-streams are further protected against errors via channel codes and the Parity bits of these codes are embedded into other slices. In this manner, implicit utilization of error correction codes improves the reconstruction quality significantly. The simulation results show that the proposed approaches perform quite promising for concealing the errors in any compressed video bit-stream.

  • ICIP (2) - Error concealment of video sequences by data hiding
    Proceedings 2003 International Conference on Image Processing (Cat. No.03CH37429), 1
    Co-Authors: Alper Yilmaz, A. Aydin Alatan
    Abstract:

    A complete error resilient video transmission codec is proposed, utilizing imperceptible embedded Information for combined detecting, resynchronization and reconstruction of the errors and lost data. Utilization of data hiding for this problem provides a reserve Information about the video to the receiver while unchanging the transmitted bit-stream syntax; hence, improves the reconstruction video quality without significant extra channel utilization. A spatial domain error recovery technique, which hides edge orientation Information of a block, and a resynchronization technique, which embeds bit-length of a block into other blocks are combined, as well as some Parity Information about the hidden data, to conceal channel errors on intra-coded frames of a video sequence. The inter-coded frames are basically recovered by hiding motion vector Information into the next frames. The simulation results show that the proposed approach performs superior to conventional approaches for concealing the errors in binary symmetric channels, especially for higher bit-rates and error-rates.

Yoo-hun Won - One of the best experts on this subject based on the ideXlab platform.

  • A storage strategy considering characteristics of video objects on Video-On-Demand storage servers
    Proceedings Fourth International Conference Exhibition on High Performance Computing in the Asia-Pacific Region, 2000
    Co-Authors: You-jung Ahn, Yoo-hun Won
    Abstract:

    One of the most important goals of VOD servers is to provide maximum users with retrieval services concurrently. To approach the goal, it is necessary to use an efficient storage strategy that can place video objects on the storage media efficiently and retrieve them more rapidly. However, occasionally, to emphasise retrieval efficiency makes reliability insufficient. On the VOD server, trivial errors may be ignored, however some fatal errors may damage systems. So, it is necessary for storage servers to manage Parity Information like RAID. The authors propose a novel storage strategy to provide both higher retrieval efficiency and reliability. In particular, the strategy is designed to fully utilize the I/O bandwidth of disks and characteristics of video objects to be stored, so that it provides high retrieval performance. Also, it has an efficient architecture of storage system to allow it to manage Parity Information. Lastly, we simulate our strategy and conventional strategies through various experiments and evaluate the number of supportable video streams. In these experiments, we show that our strategy performs better than others.

Shi Jin - One of the best experts on this subject based on the ideXlab platform.

  • APWCS - TurboNet: A Model-driven DNN Decoder Based on Max-Log-MAP Algorithm for Turbo Code
    2019 IEEE VTS Asia Pacific Wireless Communications Symposium (APWCS), 2019
    Co-Authors: Yunfeng He, Jing Zhang, Chao-kai Wen, Shi Jin
    Abstract:

    This paper presents TurboNet, a novel model-driven deep learning (DL) architecture for turbo decoding that combines DL with the traditional max-log-maximum a posteriori (MAP) algorithm. To design TurboNet, we unfold the original iterative structure for turbo decoding and replace each iteration by a deep neural network (DNN) decoding unit. In particular, the DNN decoding unit is obtained by parameterizing the max-log- MAP algorithm rather than replace the whole decoder with a black box fully connected DNN architecture. With the proposed architecture, the parameters can be efficiently learned from training data, and thus TurboNet learns to appropriately use systematic and Parity Information to offer higher error correction capabilities and decrease computational complexity compared with existing methods. Furthermore, simulation results prove TurboNet's superiority in signal-to-noise ratio generalizations.

  • TurboNet: A Model-driven DNN Decoder Based on Max-Log-MAP Algorithm for Turbo Code
    arXiv: Signal Processing, 2019
    Co-Authors: Yunfeng He, Jing Zhang, Chao-kai Wen, Shi Jin
    Abstract:

    This paper presents TurboNet, a novel model-driven deep learning (DL) architecture for turbo decoding that combines DL with the traditional max-log-maximum a posteriori (MAP) algorithm. To design TurboNet, we unfold the original iterative structure for turbo decoding and replace each iteration by a deep neural network (DNN) decoding unit. In particular, the DNN decoding unit is obtained by parameterizing the max-log-MAP algorithm rather than replace the whole decoder with a black box fully connected DNN architecture. With the proposed architecture, the parameters can be efficiently learned from training data, and thus TurboNet learns to appropriately use systematic and Parity Information to offer higher error correction capabilities and decrease computational complexity compared with existing methods. Furthermore, simulation results prove TurboNet's superiority in signal-to-noise ratio generalizations.

Joao P. Vilela - One of the best experts on this subject based on the ideXlab platform.

  • VTC Spring - Testbed Implementation and Evaluation of Interleaved and Scrambled Coding for Physical-Layer Security
    2018 IEEE 87th Vehicular Technology Conference (VTC Spring), 2018
    Co-Authors: Cesar Martins, Telmo R. Fernandes, Marco Gomes, Joao P. Vilela
    Abstract:

    This paper presents a testbed implementation and evaluation of coding for secrecy schemes in a real environment through software defined radio platforms. These coding schemes rely on interleaving and scrambling with randomly generated keys to shuffle Information before transmission. These keys are then encoded jointly with data and then hidden (erased) before transmission, thus only being retrievable through Parity Information resulting from encoded data. An advantage of the legitimate receiver (e.g. a better signal-to-noise ratio) on the reception of those keys provides the means to achieve secrecy against an adversary eavesdropper. Through this testbed implementation, we show the practical feasibility of coding for secrecy schemes in real-world environments, unveiling the usefulness of interleaving and scrambling with a hidden key to reduce the required advantage over an eavesdropper. We further describe and present solutions to a set of issues that appear when doing practical implementations of security schemes in software defined radio platforms.