4 research outputs found
On Separation for Multiple Access Channels
We examine the issue of separation for multiple access channels. We demonstrate that source-channel separation holds for noisy multiple access channels, when the channel operates over a common finite field. This robustness of separation is predicated on the fact that noise and inputs are independent, and we examine the loss from failure of separation when noise is input dependent
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The Capacity of Linear Computation Broadcast
The two-user computation broadcast problem is introduced as the setting where user 1 wants message W1 and has side information W0 1 , user 2 wants message W2 and has side information W0 2, and (W1;W0 1 ;W2;W0 2) may have arbitrary dependencies. The goal is to minimize the entropy H(S) of the broadcast information S that simultaneously satisfies both users' demands. It is shown that H(S) H(W1jW0 1) + H(W2jW0 2) min I(W1;W2;W0 2jW0 1 ); I(W2;W1;W0 1jW0 2 ) . Furthermore, for the linear computation broadcast problem, where W1;W0 1;W2;W0 2 are comprised of arbitrary linear combinations of a basis set of independent symbols, the bound is shown to be tight
A Graph-based Framework for Transmission of Correlated Sources over Broadcast Channels
In this paper we consider the communication problem that involves
transmission of correlated sources over broadcast channels. We consider a
graph-based framework for this information transmission problem. The system
involves a source coding module and a channel coding module. In the source
coding module, the sources are efficiently mapped into a nearly semi-regular
bipartite graph, and in the channel coding module, the edges of this graph are
reliably transmitted over a broadcast channel. We consider nearly semi-regular
bipartite graphs as discrete interface between source coding and channel coding
in this multiterminal setting. We provide an information-theoretic
characterization of (1) the rate of exponential growth (as a function of the
number of channel uses) of the size of the bipartite graphs whose edges can be
reliably transmitted over a broadcast channel and (2) the rate of exponential
growth (as a function of the number of source samples) of the size of the
bipartite graphs which can reliably represent a pair of correlated sources to
be transmitted over a broadcast channel.Comment: 36 pages, 9 figure