The Experts below are selected from a list of 144 Experts worldwide ranked by ideXlab platform

Kaibi Huang - One of the best experts on this subject based on the ideXlab platform.

  • Fast Analog Transmission for High-Mobility Wireless Data Acquisition in Edge Learning
    IEEE Wireless Communications Letters, 2019
    Co-Authors: Kaibi Huang
    Abstract:

    By implementing machine learning at the network edge, edge learning trains models by leveraging rich data distributed at edge devices and in return endow on them capabilities of seeing, listening, and reasoning. In edge learning, the need of high-mobility wireless data acquisition arises in scenarios where edge devices (or even servers) are mounted on ground or aerial vehicles. In this letter, we present a novel solution, called fast Analog Transmission (FAT), for high-mobility data acquisition in edge-learning systems, which has several key features. First, FAT incurs low-latency. Specifically, FAT requires no source-and-channel coding and no channel training via the proposed technique of Grassmann Analog encoding (GAE) that encodes data samples into subspace matrices. Second, FAT supports spatial multiplexing by directly transmitting Analog vector data over an antenna array. Third, FAT can be seamlessly integrated with edge learning (i.e., training of a classifier model in this letter). In particular, by applying a Grassmannian-classification algorithm from computer vision, the received GAE encoded data can be directly applied to training the model without decoding and conversion. This design is found by simulation to outperform conventional schemes in learning accuracy at a moderate-SNR range under the high mobility scenario due to its robustness against data distortion induced by fast fading.

Wenjun Zeng - One of the best experts on this subject based on the ideXlab platform.

  • a practical hybrid digital Analog scheme for wireless video Transmission
    IEEE Transactions on Circuits and Systems for Video Technology, 2018
    Co-Authors: Cuiling Lan, Chong Luo, Wenjun Zeng
    Abstract:

    We propose a hybrid digital-Analog framework for wireless video Transmission, which benefits from both the high distortion-power performance of digital systems and the graceful performance degradation of Analog systems. The proposed framework models video frames as a parallel Gaussian source, which is separated into digital and Analog parts through scalar quantization. It features entropy coding and channel coding in digital Transmission and power scaling in Analog Transmission. The key challenge in this framework is how to allocate the constrained power and bandwidth resources between and among digital and Analog components to achieve minimal distortion at the receiver. Given the worst-case channel signal-to-noise ratio, we are able to derive a closed-form expression of the overall distortion. However, minimizing it is a mixed-integer non-linear programming problem, which is generally non-deterministic polynomial-time hard. By making reasonable and justified simplifications, we approach the optimal solution through a practical scheme. Evaluations show that the proposed scheme outperforms the state-of-the-art Analog scheme SoftCast by a large margin. The gain in received video peak signal-to-noise ratio is up to 5.0 dB for various types of videos.

  • progressive pseudo Analog Transmission for mobile video streaming
    IEEE Transactions on Multimedia, 2017
    Co-Authors: Cuiling Lan, Chong Luo, Enhong Chen, Wenjun Zeng
    Abstract:

    We propose a progressive pseudo-Analog video Transmission scheme that simultaneously handles SNR and bandwidth variations with graceful quality degradation for mobile video streaming. With the inherited SNR-adaptability from pseudo-Analog Transmission, the proposed progressive solution acquires bandwidth adaptability through an innovative scheduling algorithm with optimal power allocation. The basic idea is to aggressively transmit or retransmit important coefficients so that distortion is minimized at the receiver after each received packet. We derive the closed-form expression of reduced distortion for each packet under given Transmission power and known channel conditions, and show that the optimal solution can be obtained with a water-filling algorithm. We also illustrate through analyses and simulations that a near-optimal solution can be found through approximation when only statistical channel information is available. Simulations show that our solution approaches the performance upper bound of pseudo-Analog Transmission in an additive white Gaussian noise channel and significantly outperforms existing pseudo-Analog solutions in a fast Rayleigh fading channel. Trace-driven emulations are also carried out to demonstrate the advantage of the proposed solution over the state-of-the-art digital and pseudo-Analog solutions under a real dramatically varying wireless environment.

  • bandwidth compression for a bivariate gaussian source with shannon kotel nikov mappings
    CTIT technical reports series, 2016
    Co-Authors: Fei Liang, Chong Luo, Wenjun Zeng
    Abstract:

    The Analog Transmission of a bivariate Gaussian source over a white Gaussian channel with 2:1 bandwidth compression is addressed in this paper. We propose two nonlinear coding structures for bandwidth compression based on the Shannon-Kotel’nikov (S-K) mappings. For each coding structure, the closed-form expression of distortion at any given channel SNR is derived and the optimal energy scaling for each source is computed. We perform theoretical deduction and numerical evaluations to compare the performances of the proposed schemes with a baseline linear mapping scheme. Results show that nonlinear schemes are superior to the linear scheme when the channel condition is good and the difference between the two sources is not too large. Among the proposed nonlinear schemes, the design to combine the two sources for S-K mapping with the optimal energy scaling yields the best performance.

Deniz Gunduz - One of the best experts on this subject based on the ideXlab platform.

  • wyner ziv coding over broadcast channels using hybrid digital Analog Transmission
    International Symposium on Information Theory, 2008
    Co-Authors: Deniz Gunduz, J Nayak, Ertem Tuncel
    Abstract:

    This paper deals with the design of coding schemes for transmitting a source over a broadcast channel when there is source side information at the receivers. Based on Slepian-Wolf coding over broadcast channels, three hybrid digital/Analog schemes are proposed and their power-distortion tradeoff is investigated for Gaussian sources and Gaussian broadcast channels. All three transmit the same digital and Analog information but with varying coding order. Although they are not provably optimal in general, they can significantly outperform uncoded Transmission and separate source and channel coding.

  • joint source channel codes for mimo block fading channels
    IEEE Transactions on Information Theory, 2008
    Co-Authors: Deniz Gunduz, Elza Erkip
    Abstract:

    We consider Transmission of a continuous amplitude source over an L-block Rayleigh-fading Mt x Mr multiple-input multiple-output (MIMO) channel when the channel state information is only available at the receiver. Since the channel is not ergodic, Shannon's source-channel separation theorem becomes obsolete and the optimal performance requires a joint source-channel approach. Our goal is to minimize the expected end-to-end distortion, particularly in the high signal-to-noise ratio (SNR) regime. The figure of merit is the distortion exponent, defined as the exponential decay rate of the expected distortion with increasing SNR. We provide an upper bound and lower bounds for the distortion exponent with respect to the bandwidth ratio among the channel and source bandwidths. For the lower bounds, we analyze three different strategies based on layered source coding concatenated with progressive superposition or hybrid digital/Analog Transmission. In each case, by adjusting the system parameters we optimize the distortion exponent as a function of the bandwidth ratio. We prove that the distortion exponent upper bound can be achieved when the channel has only one degree of freedom, that is L = 1, and min{Mt ,Mr} =1. When we have more degrees of freedom, our achievable distortion exponents meet the upper bound for only certain ranges of the bandwidth ratio. We demonstrate that our results, which were derived for a complex Gaussian source, can be extended to more general source distributions as well.

  • joint source channel codes for mimo block fading channels
    arXiv: Information Theory, 2007
    Co-Authors: Deniz Gunduz, Elza Erkip
    Abstract:

    We consider Transmission of a continuous amplitude source over an L-block Rayleigh fading $M_t \times M_r$ MIMO channel when the channel state information is only available at the receiver. Since the channel is not ergodic, Shannon's source-channel separation theorem becomes obsolete and the optimal performance requires a joint source -channel approach. Our goal is to minimize the expected end-to-end distortion, particularly in the high SNR regime. The figure of merit is the distortion exponent, defined as the exponential decay rate of the expected distortion with increasing SNR. We provide an upper bound and lower bounds for the distortion exponent with respect to the bandwidth ratio among the channel and source bandwidths. For the lower bounds, we analyze three different strategies based on layered source coding concatenated with progressive, superposition or hybrid digital/Analog Transmission. In each case, by adjusting the system parameters we optimize the distortion exponent as a function of the bandwidth ratio. We prove that the distortion exponent upper bound can be achieved when the channel has only one degree of freedom, that is L=1, and $\min\{M_t,M_r\}=1$. When we have more degrees of freedom, our achievable distortion exponents meet the upper bound for only certain ranges of the bandwidth ratio. We demonstrate that our results, which were derived for a complex Gaussian source, can be extended to more general source distributions as well.

Cuiling Lan - One of the best experts on this subject based on the ideXlab platform.

  • a practical hybrid digital Analog scheme for wireless video Transmission
    IEEE Transactions on Circuits and Systems for Video Technology, 2018
    Co-Authors: Cuiling Lan, Chong Luo, Wenjun Zeng
    Abstract:

    We propose a hybrid digital-Analog framework for wireless video Transmission, which benefits from both the high distortion-power performance of digital systems and the graceful performance degradation of Analog systems. The proposed framework models video frames as a parallel Gaussian source, which is separated into digital and Analog parts through scalar quantization. It features entropy coding and channel coding in digital Transmission and power scaling in Analog Transmission. The key challenge in this framework is how to allocate the constrained power and bandwidth resources between and among digital and Analog components to achieve minimal distortion at the receiver. Given the worst-case channel signal-to-noise ratio, we are able to derive a closed-form expression of the overall distortion. However, minimizing it is a mixed-integer non-linear programming problem, which is generally non-deterministic polynomial-time hard. By making reasonable and justified simplifications, we approach the optimal solution through a practical scheme. Evaluations show that the proposed scheme outperforms the state-of-the-art Analog scheme SoftCast by a large margin. The gain in received video peak signal-to-noise ratio is up to 5.0 dB for various types of videos.

  • progressive pseudo Analog Transmission for mobile video streaming
    IEEE Transactions on Multimedia, 2017
    Co-Authors: Cuiling Lan, Chong Luo, Enhong Chen, Wenjun Zeng
    Abstract:

    We propose a progressive pseudo-Analog video Transmission scheme that simultaneously handles SNR and bandwidth variations with graceful quality degradation for mobile video streaming. With the inherited SNR-adaptability from pseudo-Analog Transmission, the proposed progressive solution acquires bandwidth adaptability through an innovative scheduling algorithm with optimal power allocation. The basic idea is to aggressively transmit or retransmit important coefficients so that distortion is minimized at the receiver after each received packet. We derive the closed-form expression of reduced distortion for each packet under given Transmission power and known channel conditions, and show that the optimal solution can be obtained with a water-filling algorithm. We also illustrate through analyses and simulations that a near-optimal solution can be found through approximation when only statistical channel information is available. Simulations show that our solution approaches the performance upper bound of pseudo-Analog Transmission in an additive white Gaussian noise channel and significantly outperforms existing pseudo-Analog solutions in a fast Rayleigh fading channel. Trace-driven emulations are also carried out to demonstrate the advantage of the proposed solution over the state-of-the-art digital and pseudo-Analog solutions under a real dramatically varying wireless environment.

Elza Erkip - One of the best experts on this subject based on the ideXlab platform.

  • joint source channel codes for mimo block fading channels
    IEEE Transactions on Information Theory, 2008
    Co-Authors: Deniz Gunduz, Elza Erkip
    Abstract:

    We consider Transmission of a continuous amplitude source over an L-block Rayleigh-fading Mt x Mr multiple-input multiple-output (MIMO) channel when the channel state information is only available at the receiver. Since the channel is not ergodic, Shannon's source-channel separation theorem becomes obsolete and the optimal performance requires a joint source-channel approach. Our goal is to minimize the expected end-to-end distortion, particularly in the high signal-to-noise ratio (SNR) regime. The figure of merit is the distortion exponent, defined as the exponential decay rate of the expected distortion with increasing SNR. We provide an upper bound and lower bounds for the distortion exponent with respect to the bandwidth ratio among the channel and source bandwidths. For the lower bounds, we analyze three different strategies based on layered source coding concatenated with progressive superposition or hybrid digital/Analog Transmission. In each case, by adjusting the system parameters we optimize the distortion exponent as a function of the bandwidth ratio. We prove that the distortion exponent upper bound can be achieved when the channel has only one degree of freedom, that is L = 1, and min{Mt ,Mr} =1. When we have more degrees of freedom, our achievable distortion exponents meet the upper bound for only certain ranges of the bandwidth ratio. We demonstrate that our results, which were derived for a complex Gaussian source, can be extended to more general source distributions as well.

  • joint source channel codes for mimo block fading channels
    arXiv: Information Theory, 2007
    Co-Authors: Deniz Gunduz, Elza Erkip
    Abstract:

    We consider Transmission of a continuous amplitude source over an L-block Rayleigh fading $M_t \times M_r$ MIMO channel when the channel state information is only available at the receiver. Since the channel is not ergodic, Shannon's source-channel separation theorem becomes obsolete and the optimal performance requires a joint source -channel approach. Our goal is to minimize the expected end-to-end distortion, particularly in the high SNR regime. The figure of merit is the distortion exponent, defined as the exponential decay rate of the expected distortion with increasing SNR. We provide an upper bound and lower bounds for the distortion exponent with respect to the bandwidth ratio among the channel and source bandwidths. For the lower bounds, we analyze three different strategies based on layered source coding concatenated with progressive, superposition or hybrid digital/Analog Transmission. In each case, by adjusting the system parameters we optimize the distortion exponent as a function of the bandwidth ratio. We prove that the distortion exponent upper bound can be achieved when the channel has only one degree of freedom, that is L=1, and $\min\{M_t,M_r\}=1$. When we have more degrees of freedom, our achievable distortion exponents meet the upper bound for only certain ranges of the bandwidth ratio. We demonstrate that our results, which were derived for a complex Gaussian source, can be extended to more general source distributions as well.