548 research outputs found
Tight Lower Bounds on the Contact Distance Distribution in Poisson Hole Process
In this letter, we derive new lower bounds on the cumulative distribution
function (CDF) of the contact distance in the Poisson Hole Process (PHP) for
two cases: (i) reference point is selected uniformly at random from
independently of the PHP, and (ii) reference point is located at
the center of a hole selected uniformly at random from the PHP. While one can
derive upper bounds on the CDF of contact distance by simply ignoring the
effect of holes, deriving lower bounds is known to be relatively more
challenging. As a part of our proof, we introduce a tractable way of bounding
the effect of all the holes in a PHP, which can be used to study other
properties of a PHP as well.Comment: To appear in IEEE Wireless Communications Letter
Coexistence of RF-powered IoT and a Primary Wireless Network with Secrecy Guard Zones
This paper studies the secrecy performance of a wireless network (primary
network) overlaid with an ambient RF energy harvesting IoT network (secondary
network). The nodes in the secondary network are assumed to be solely powered
by ambient RF energy harvested from the transmissions of the primary network.
We assume that the secondary nodes can eavesdrop on the primary transmissions
due to which the primary network uses secrecy guard zones. The primary
transmitter goes silent if any secondary receiver is detected within its guard
zone. Using tools from stochastic geometry, we derive the probability of
successful connection of the primary network as well as the probability of
secure communication. Two conditions must be jointly satisfied in order to
ensure successful connection: (i) the SINR at the primary receiver is above a
predefined threshold, and (ii) the primary transmitter is not silent. In order
to ensure secure communication, the SINR value at each of the secondary nodes
should be less than a predefined threshold. Clearly, when more secondary nodes
are deployed, more primary transmitters will remain silent for a given guard
zone radius, thus impacting the amount of energy harvested by the secondary
network. Our results concretely show the existence of an optimal deployment
density for the secondary network that maximizes the density of nodes that are
able to harvest sufficient amount of energy. Furthermore, we show the
dependence of this optimal deployment density on the guard zone radius of the
primary network. In addition, we show that the optimal guard zone radius
selected by the primary network is a function of the deployment density of the
secondary network. This interesting coupling between the two networks is
studied using tools from game theory. Overall, this work is one of the few
concrete works that symbiotically merge tools from stochastic geometry and game
theory
A Stochastic Geometry approach towards Green Communications in 5G
In this dissertation, we investigate two main research directions towards net- work efficiency and green communications in heterogeneous cellular networks (HetNets) as a promising network structure for the fifth generation of mobile systems. In order to analyze the networks, we use a powerful mathematical tool, named stochastic geometry. In our research, first we study the performance of MIMO technology in single-tier and two-tier HetNets. In this work, we apply a more realistic network model in which the correlation between tiers is taken into account. Comparing the obtained results with the commonly used model shows performance enhancement and greater efficiencies in cellular networks. As the second part of our research, we apply two Cell Zooming (CZ) techniques to HetNets. With focus on green communications, we present a K−tier HetNet in which BSs are only powered by energy har- vesting. Despite the uncertain nature of energy arrivals, combining two CZ techniques, namely telescopic and ON/OFF scenarios, enables us to achieve higher network performance in terms of the coverage and blocking probabilities while reducing the total power consumption and increasing the energy and spectral efficiencies
Network-Level Integrated Sensing and Communication: Interference Management and BS Coordination Using Stochastic Geometry
In this work, we study integrated sensing and communication (ISAC) networks
with the aim of effectively balancing sensing and communication (S&C)
performance at the network level. Focusing on monostatic sensing, the tool of
stochastic geometry is exploited to capture the S&C performance, which
facilitates us to illuminate key cooperative dependencies in the ISAC network
and optimize key network-level parameters. Based on the derived tractable
expression of area spectral efficiency (ASE), we formulate the optimization
problem to maximize the network performance from the view point of two joint
S&C metrics. Towards this end, we further jointly optimize the cooperative BS
cluster sizes for S&C and the serving/probing numbers of users/targets to
achieve a flexible tradeoff between S&C at the network level. It is verified
that interference nulling can effectively improve the average data rate and
radar information rate. Surprisingly, the optimal communication tradeoff for
the case of the ASE maximization tends to employ all spacial resources towards
multiplexing and diversity gain, without interference nulling. By contrast, for
the sensing objectives, resource allocation tends to eliminate certain
interference especially when the antenna resources are sufficient, because the
inter-cell interference becomes a more dominant factor affecting sensing
performance. Furthermore, we prove that the ratio of the optimal number of
users and the number of transmit antennas is a constant value when the
communication performance is optimal. Simulation results demonstrate that the
proposed cooperative ISAC scheme achieves a substantial gain in S&C performance
at the network level.Comment: 13 pages, 12 figures. This work has been submitted to the IEEE for
possible publicatio
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