Journal ArticleDOI
Hybrid digital-analog (HDA) joint source-channel codes for broadcasting and robust communications
U. Mittal,N. Phamdo +1 more
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TLDR
It is demonstrated that robust codes exist whenever the source and channel bandwidths are equal and a matched tandem code whose channel encoder's output is partially/fully matched to its input is proposed and the existence of an asymptotically optimal matched tandemcode is shown.Abstract:
We consider the problem of transmitting a band-limited Gaussian source on an additive band-limited Gaussian noise channel. The well-known "threshold effect" dictates that the more powerful a code is, the more sensitive it is to the exact knowledge of the channel noise. A code is said to be robust if it is asymptotically optimal for a wide range of channel noise. Thus, robust codes have a "graceful degradation" characteristic and are free of the threshold effect. It is demonstrated that robust codes exist whenever the source and channel bandwidths are equal. In the unequal-bandwidth case, a collection of nearly robust joint source-channel codes is constructed using a hybrid digital-analog (HDA) coding technique. For designing nearly robust codes, a matched tandem code whose channel encoder's output is partially/fully matched to its input is proposed and the existence of an asymptotically optimal matched tandem code is shown. The nearly robust codes achieve the Shannon limit (theoretically optimum distortion) and have a less severe threshold effect. Finally, for the case of two different noise conditions, the distortion regions of these codes are determined.read more
Citations
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Proceedings ArticleDOI
A cross-layer design for scalable mobile video
Szymon Jakubczak,Dina Katabi +1 more
TL;DR: SoftCast is presented, a cross-layer design for mobile video that improves the average video quality for multicast users by 5.5dB, eliminates video glitches caused by mobility, and increases robustness to packet loss by an order of magnitude.
Journal ArticleDOI
Slepian-Wolf coding over broadcast channels
TL;DR: It is shown with an example that an optimal joint source-channel coding strategy is strictly advantageous over the combination of stand-alone source and channel codes, and thus "informational separation" does not hold.
Journal ArticleDOI
Distortion Bounds for Broadcasting With Bandwidth Expansion
Z. Reznic,Meir Feder,Ram Zamir +2 more
TL;DR: It is shown how a system with a partial feedback, returning from the bad receiver to the transmitter and to the good receiver, achieves a distortion pair that lies on the outer bound derived here.
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Hiding a Large Amount of Data with High Security Using Steganography Algorithm
TL;DR: The algorithm can embed efficiently a large amount of data that has been reached to 75% of the image size with high quality of the output and make comparison with the previous Steganography algorithms like S-Tools.
Journal ArticleDOI
Shannon-kotel-nikov mappings in joint source-channel coding
TL;DR: A general theory for 1:N and M:1 dimension changing mappings is presented, and two examples for a Gaussian source and channel are provided where both a 2:1 bandwidth-reducing and a 1:2 bandwidth-expanding mapping are optimized.
References
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TL;DR: A method is developed for representing any communication system geometrically and a number of results in communication theory are deduced concerning expansion and compression of bandwidth and the threshold effect.
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W.H.R. Equitz,Thomas M. Cover +1 more
TL;DR: It is shown that in order to achieve optimal successive refinement the necessary and sufficient conditions are that the solutions of the rate distortion problem can be written as a Markov chain and all finite alphabet signals with Hamming distortion satisfy these requirements.
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A study of vector quantization for noisy channels
TL;DR: It is concluded that the channel-optimized vector quantizer design algorithm, if used carefully, can result in a fairly robust system with no additional delay.
Journal ArticleDOI
A simple converse for broadcast channels with additive white Gaussian noise (Corresp.)
TL;DR: A simple converse is established showing the optimality of sets of achievable rates for the additive white Gaussian noise broadcast channel, found by Cover and generalized by Bergmans.