439,407 research outputs found
Asymptotically Optimal Joint Source-Channel Coding with Minimal Delay
We present and analyze a joint source-channel coding strategy for the
transmission of a Gaussian source across a Gaussian channel in n channel uses
per source symbol. Among all such strategies, our scheme has the following
properties: i) the resulting mean-squared error scales optimally with the
signal-to-noise ratio, and ii) the scheme is easy to implement and the incurred
delay is minimal, in the sense that a single source symbol is encoded at a
time.Comment: 5 pages, 1 figure, final version accepted at IEEE Globecom 2009
(Communication Theory Symposium
Bit rates in audio source coding
The goal is to introduce and solve the audio coding optimization problem. Psychoacoustic results such as masking and excitation pattern models are combined with results from rate distortion theory to formulate the audio coding optimization problem. The solution of the audio optimization problem is a masked error spectrum, prescribing how quantization noise must be distributed over the audio spectrum to obtain a minimal bit rate and an inaudible coding errors. This result cannot only be used to estimate performance bounds, but can also be directly applied in audio coding systems. Subband coding applications to magnetic recording and transmission are discussed in some detail. Performance bounds for this type of subband coding system are derived
A Minimal Set of Shannon-type Inequalities for Functional Dependence Structures
The minimal set of Shannon-type inequalities (referred to as elemental
inequalities), plays a central role in determining whether a given inequality
is Shannon-type. Often, there arises a situation where one needs to check
whether a given inequality is a constrained Shannon-type inequality. Another
important application of elemental inequalities is to formulate and compute the
Shannon outer bound for multi-source multi-sink network coding capacity. Under
this formulation, it is the region of feasible source rates subject to the
elemental inequalities and network coding constraints that is of interest.
Hence it is of fundamental interest to identify the redundancies induced
amongst elemental inequalities when given a set of functional dependence
constraints. In this paper, we characterize a minimal set of Shannon-type
inequalities when functional dependence constraints are present.Comment: 5 pagers, accepted ISIT201
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