12 research outputs found
On AVCs with Quadratic Constraints
In this work we study an Arbitrarily Varying Channel (AVC) with quadratic
power constraints on the transmitter and a so-called "oblivious" jammer (along
with additional AWGN) under a maximum probability of error criterion, and no
private randomness between the transmitter and the receiver. This is in
contrast to similar AVC models under the average probability of error criterion
considered in [1], and models wherein common randomness is allowed [2] -- these
distinctions are important in some communication scenarios outlined below.
We consider the regime where the jammer's power constraint is smaller than
the transmitter's power constraint (in the other regime it is known no positive
rate is possible). For this regime we show the existence of stochastic codes
(with no common randomness between the transmitter and receiver) that enables
reliable communication at the same rate as when the jammer is replaced with
AWGN with the same power constraint. This matches known information-theoretic
outer bounds. In addition to being a stronger result than that in [1] (enabling
recovery of the results therein), our proof techniques are also somewhat more
direct, and hence may be of independent interest.Comment: A shorter version of this work will be send to ISIT13, Istanbul. 8
pages, 3 figure
Simulation of a Channel with Another Channel
In this paper, we study the problem of simulating a DMC channel from another
DMC channel under an average-case and an exact model. We present several
achievability and infeasibility results, with tight characterizations in
special cases. In particular for the exact model, we fully characterize when a
BSC channel can be simulated from a BEC channel when there is no shared
randomness. We also provide infeasibility and achievability results for
simulation of a binary channel from another binary channel in the case of no
shared randomness. To do this, we use properties of R\'enyi capacity of a given
order. We also introduce a notion of "channel diameter" which is shown to be
additive and satisfy a data processing inequality.Comment: 31 pages, 10 figures, and some parts of this work were published at
ITW 201