2,607 research outputs found
Coding and Decoding Schemes for MSE and Image Transmission
In this work we explore possibilities for coding and decoding tailor-made for
mean squared error evaluation of error in contexts such as image transmission.
To do so, we introduce a loss function that expresses the overall performance
of a coding and decoding scheme for discrete channels and that exchanges the
usual goal of minimizing the error probability to that of minimizing the
expected loss. In this environment we explore the possibilities of using
ordered decoders to create a message-wise unequal error protection (UEP), where
the most valuable information is protected by placing in its proximity
information words that differ by a small valued error. We give explicit
examples, using scale-of-gray images, including small-scale performance
analysis and visual simulations for the BSMC.Comment: Submitted to IEEE Transactions on Information Theor
Approximate Decoding Approaches for Network Coded Correlated Data
This paper considers a framework where data from correlated sources are
transmitted with help of network coding in ad-hoc network topologies. The
correlated data are encoded independently at sensors and network coding is
employed in the intermediate nodes in order to improve the data delivery
performance. In such settings, we focus on the problem of reconstructing the
sources at decoder when perfect decoding is not possible due to losses or
bandwidth bottlenecks. We first show that the source data similarity can be
used at decoder to permit decoding based on a novel and simple approximate
decoding scheme. We analyze the influence of the network coding parameters and
in particular the size of finite coding fields on the decoding performance. We
further determine the optimal field size that maximizes the expected decoding
performance as a trade-off between information loss incurred by limiting the
resolution of the source data and the error probability in the reconstructed
data. Moreover, we show that the performance of the approximate decoding
improves when the accuracy of the source model increases even with simple
approximate decoding techniques. We provide illustrative examples about the
possible of our algorithms that can be deployed in sensor networks and
distributed imaging applications. In both cases, the experimental results
confirm the validity of our analysis and demonstrate the benefits of our low
complexity solution for delivery of correlated data sources
Analog Multiple Descriptions: A Zero-Delay Source-Channel Coding Approach
This paper extends the well-known source coding problem of multiple
descriptions, in its general and basic setting, to analog source-channel coding
scenarios. Encoding-decoding functions that optimally map between the (possibly
continuous valued) source and the channel spaces are numerically derived. The
main technical tool is a non-convex optimization method, namely, deterministic
annealing, which has recently been successfully used in other mapping
optimization problems. The obtained functions exhibit several interesting
structural properties, map multiple source intervals to the same interval in
the channel space, and consistently outperform the known competing mapping
techniques.Comment: Submitted to ICASSP 201
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