4,911 research outputs found
Distortion Metrics of Composite Channels with Receiver Side Information
We consider transmission of stationary ergodic sources over non-ergodic composite channels with channel state information at the receiver (CSIR). Previously we introduced alternative capacity definitions to Shannon capacity, including outage and expected capacity. These generalized definitions relax the constraint of Shannon capacity that all transmitted information must be decoded at the receiver. In this work alternative end- to-end distortion metrics such as outage and expected distortion are introduced to relax the constraint that a single distortion level has to be maintained for all channel states. Through the example of transmission of a Gaussian source over a slow-fading Gaussian channel, we illustrate that the end-to-end distortion metrics dictate whether the source and channel coding can be separated for a communication system. We also show that the source and channel need to exchange information through an appropriate interface to facilitate separate encoding and decoding
Wyner-Ziv Coding over Broadcast Channels: Digital Schemes
This paper addresses lossy transmission of a common source over a broadcast
channel when there is correlated side information at the receivers, with
emphasis on the quadratic Gaussian and binary Hamming cases. A digital scheme
that combines ideas from the lossless version of the problem, i.e.,
Slepian-Wolf coding over broadcast channels, and dirty paper coding, is
presented and analyzed. This scheme uses layered coding where the common layer
information is intended for both receivers and the refinement information is
destined only for one receiver. For the quadratic Gaussian case, a quantity
characterizing the overall quality of each receiver is identified in terms of
channel and side information parameters. It is shown that it is more
advantageous to send the refinement information to the receiver with "better"
overall quality. In the case where all receivers have the same overall quality,
the presented scheme becomes optimal. Unlike its lossless counterpart, however,
the problem eludes a complete characterization
Separate Source-Channel Coding for Broadcasting Correlated Gaussians
The problem of broadcasting a pair of correlated Gaussian sources using
optimal separate source and channel codes is studied. Considerable performance
gains over previously known separate source-channel schemes are observed.
Although source-channel separation yields suboptimal performance in general, it
is shown that the proposed scheme is very competitive for any bandwidth
compression/expansion scenarios. In particular, for a high channel SNR
scenario, it can be shown to achieve optimal power-distortion tradeoff.Comment: 6 pages (with an extra proof), ISIT2011, to appea
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