This paper establishes the sum capacity of Gaussian interfering multiple
access channels (IF-MACs) in a low interference regime. IF-MACs studied consist
of two MACs, with arbitrary number of users, interfering with each other. In
the low interference regime, treating interference as noise along with
successive decoding is shown to be sum rate optimal. The regime characterized
in this paper solely depends on the minimum direct to indirect channel gain
ratios, net interference to noise ratio and net signal to noise ratio
associated with both MACs.

The problem of compressing a real-valued sparse source using compressive
sensing techniques is studied. The rate distortion optimality of a coding
scheme in which compressively sensed signals are quantized and then
reconstructed is established when the reconstruction is also required to be
sparse. The result holds in general when the distortion constraint is on the
expected $p$-norm of error between the source and the reconstruction. A new
restricted isometry like property is introduced for this purpose and the
existence of matrices that satisfy this property is shown.

An abstraction of the physical layer coding using bit pipes that are coupled
through data-rates is insufficient to capture notions such as node cooperation
in cooperative relay networks. Consequently, network-stability analyses based
on such abstractions are valid for non-cooperative schemes alone and
meaningless for cooperative schemes. Motivated from this, this paper develops a
framework that brings the information-theoretic coding scheme together with
network-stability analysis.

This paper studies a family of multiple-access type genie-aided outer bounds
for Gaussian K-user interference channels. This family is inspired by existing
genie-aided bounding mechanisms, but differs from current approaches in its
optimization problem formulation and application. The fundamental idea behind
these bounds is to create a group of genie receivers that form multiple access
channels (MACs) that can decode a subset of the original interference channel's
messages. The MAC sum capacity of each of the genie receivers provides an outer
bound on the sum of rates for this subset.

This paper introduces the concept of incremental traceback for determining
changes in the trace of a network as it evolves with time. A distributed
algorithm, based on the methodology of algebraic traceback developed by Dean et
al, is proposed which can completely determine a path of d nodes/routers using
O(d) marked packets, and subsequently determine the changes in its topology
using O(log d) marked packets with high probability.

This paper studies the low-rank matrix completion problem from an information
theoretic perspective. The completion problem is rephrased as a communication
problem of an (uncoded) low-rank matrix source over an erasure channel. The
paper then uses achievability and converse arguments to present order-wise
optimal bounds for the completion problem.

In this paper, we study the effect of the absence of channel knowledge for
multiple-input-multiple-output (MIMO) networks. Specifically, we assume perfect
channel state information at the receivers, no channel state information at the
transmitter(s), and independent identically distributed (i.i.d.) Rayleigh
fading across antennas, users and time slots. We provide the characterization
of the degrees of freedom (DoF) region for a 2-user MIMO broadcast channel.