Consider an n-dimensional linear system where it is known that there are at
most k<n non-zero components in the initial state. The observability problem,
that is the recovery of the initial state, for such a system is considered. We
obtain sufficient conditions on the number of the available observations to be
able to recover the initial state exactly for such a system. Both deterministic
and stochastic setups are considered for system dynamics.
We consider the transmission of a Gaussian vector source over a
multi-dimensional Gaussian channel where a random or a fixed subset of the
channel outputs are erased. We consider the setup where the only encoding
operation allowed is a linear unitary transformation on the source.
We consider the capacity of memoryless finite-state multiple access channel
(FS-MAC) with causal asymmetric noisy state information available at both
transmitters and noisy state information available at the receiver. Single
letter inner and outer bounds are provided for the capacity of such channels
when the state process is independent and identically distributed. The outer
bound is attained by observing that the proposed inner bound is tight for the
sum-rate capacity.
A single-letter characterization is provided for the capacity region of
finite-state multiple-access channels, when the channel state process is an
independent and identically distributed sequence, the transmitters have access
to partial (quantized) state information, and complete channel state
information is available at the receiver. The partial channel state information
is assumed to be asymmetric at the encoders. As a main contribution, a tight
converse coding theorem is presented.
It is known that state-dependent, multi-step Lyapunov bounds lead to greatly
simplified verification theorems for stability, for large classes of Markov
chain models --- This is one component of the ``fluid model'' approach to
stability of stochastic networks. In this paper we extend the general theory to
randomized multi-step Lyapunov theory to obtain criteria for the existence of a
finite steady state, as well as finite moments.
The optimal causal coding of a partially observed Markov process is studied,
where the cost to be minimized is a bounded, non-negative, additive, measurable
single-letter function of the source and the receiver output. A structural
result is obtained extending Witsenhausen's and Walrand-Varaiya's structural
results on the optimal real-time coders to a partially observed setting. The
decentralized (multi-terminal) setup is also considered. For the case where the
source is an i.i.d.