29 research outputs found
Nomographic Functions: Efficient Computation in Clustered Gaussian Sensor Networks
In this paper, a clustered wireless sensor network is considered that is
modeled as a set of coupled Gaussian multiple-access channels. The objective of
the network is not to reconstruct individual sensor readings at designated
fusion centers but rather to reliably compute some functions thereof. Our
particular attention is on real-valued functions that can be represented as a
post-processed sum of pre-processed sensor readings. Such functions are called
nomographic functions and their special structure permits the utilization of
the interference property of the Gaussian multiple-access channel to reliably
compute many linear and nonlinear functions at significantly higher rates than
those achievable with standard schemes that combat interference. Motivated by
this observation, a computation scheme is proposed that combines a suitable
data pre- and post-processing strategy with a nested lattice code designed to
protect the sum of pre-processed sensor readings against the channel noise.
After analyzing its computation rate performance, it is shown that at the cost
of a reduced rate, the scheme can be extended to compute every continuous
function of the sensor readings in a finite succession of steps, where in each
step a different nomographic function is computed. This demonstrates the
fundamental role of nomographic representations.Comment: to appear in IEEE Transactions on Wireless Communication
Resolvability on Continuous Alphabets
We characterize the resolvability region for a large class of point-to-point
channels with continuous alphabets. In our direct result, we prove not only the
existence of good resolvability codebooks, but adapt an approach based on the
Chernoff-Hoeffding bound to the continuous case showing that the probability of
drawing an unsuitable codebook is doubly exponentially small. For the converse
part, we show that our previous elementary result carries over to the
continuous case easily under some mild continuity assumption.Comment: v2: Corrected inaccuracies in proof of direct part. Statement of
Theorem 3 slightly adapted; other results unchanged v3: Extended version of
camera ready version submitted to ISIT 201
Planning of Cellular Networks Enhanced by Energy Harvesting
We pose a novel cellular network planning problem, considering the use of
renewable energy sources and a fundamentally new concept of energy balancing,
and propose a novel algorithm to solve it. In terms of the network capital and
operational expenditure, we conclude that savings can be made by enriching
cellular infrastructure with energy harvesting sources, in comparison to
traditional deployment methods.Comment: accepted to IEEE Communications Letters [source code available
Robust cell-free mmWave/sub-THz access using minimal coordination and coarse synchronization
This study investigates simpler alternatives to coherent joint transmission
for supporting robust connectivity against signal blockage in mmWave/sub-THz
access networks. By taking an information-theoretic viewpoint, we demonstrate
analytically that with a careful design, full macrodiversity gains and
significant SNR gains can be achieved through canonical receivers and minimal
coordination and synchronization requirements at the infrastructure side. Our
proposed scheme extends non-coherent joint transmission by employing a special
form of diversity to counteract artificially induced deep fades that would
otherwise make this technique often compare unfavorably against standard
transmitter selection schemes. Additionally, the inclusion of an Alamouti-like
space-time coding layer is shown to recover a significant fraction of the
optimal performance. Our conclusions are based on an insightful multi-point
intermittent block fading channel model that enables rigorous ergodic and
outage rate analysis, while also considering timing offsets due to imperfect
delay compensation. Although simplified, our approach captures the essential
features of modern mmWave/sub-THz communications, thereby providing practical
design guidelines for realistic systems
Towards Secure Over-The-Air Computation
We propose a new method to protect Over-The-Air (OTA) computation schemes
against passive eavesdropping. Our method uses a friendly jammer whose signal
is -- contrary to common intuition -- stronger at the legitimate receiver than
it is at the eavesdropper. It works for a large class of analog OTA computation
schemes and we give two examples for such schemes that are contained in this
class. The key ingredients in proving the security guarantees are a known
result on channel resolvability and a generalization of existing results on
coding for compound channels
Exploiting the Superposition Property of Wireless Communication for Max-Consensus Problems in Multi-Agent Systems
This paper presents a consensus protocol that achieves max-consensus in
multi-agent systems over wireless channels. Interference, a feature of the
wireless channel, is exploited: each agent receives a superposition of
broadcast data, rather than individual values. With this information, the
system endowed with the proposed consensus protocol reaches max-consensus in a
finite number of steps. A comparison with traditional approaches shows that the
proposed consensus protocol achieves a faster convergence.Comment: Submitted for IFAC Workshop on Distributed Estimation and Control in
Networked System