3 research outputs found
Outage Probability in Arbitrarily-Shaped Finite Wireless Networks
This paper analyzes the outage performance in finite wireless networks.
Unlike most prior works, which either assumed a specific network shape or
considered a special location of the reference receiver, we propose two general
frameworks for analytically computing the outage probability at any arbitrary
location of an arbitrarily-shaped finite wireless network: (i) a moment
generating function-based framework which is based on the numerical inversion
of the Laplace transform of a cumulative distribution and (ii) a reference link
power gain-based framework which exploits the distribution of the fading power
gain between the reference transmitter and receiver. The outage probability is
spatially averaged over both the fading distribution and the possible locations
of the interferers. The boundary effects are accurately accounted for using the
probability distribution function of the distance of a random node from the
reference receiver. For the case of the node locations modeled by a Binomial
point process and Nakagami- fading channel, we demonstrate the use of the
proposed frameworks to evaluate the outage probability at any location inside
either a disk or polygon region. The analysis illustrates the location
dependent performance in finite wireless networks and highlights the importance
of accurately modeling the boundary effects.Comment: accepted to appear in IEEE Transactions on Communication
Stochastic Geometry for Modeling, Analysis and Design of Future Wireless Networks
This thesis focuses on the modeling, analysis and design of
future wireless networks with smart devices, i.e., devices with
intelligence and ability to communicate with one another
with/without the control of base stations (BSs). Using stochastic
geometry, we develop realistic yet tractable frameworks to model
and analyze the performance of such networks, while incorporating
the intelligence features of smart devices.
In the first half of the thesis, we develop stochastic geometry
tools to study arbitrarily shaped network regions. Current
techniques in the literature assume the network regions to be
infinite, while practical network regions tend to be arbitrary.
Two well-known networks are considered, where devices have the
ability to: (i) communicate with others without the control of
BSs (i.e., ad-hoc networks), and (ii) opportunistically access
spectrum (i.e., cognitive networks). First, we propose a general
algorithm to derive the distribution of the distance between the
reference node and a random node inside an arbitrarily shaped
ad-hoc network region, which helps to compute the outage
probability. We then study the impact of boundary effects and
show that the outage probability in infinite regions may not be a
meaningful bound for arbitrarily shaped regions. By extending the
developed techniques, we further analyze the performance of
underlay cognitive networks, where different secondary users
(SUs) activity protocols are employed to limit the interference
at a primary user. Leveraging the information exchange among SUs,
we propose a cooperation-based protocol. We show that, in the
short-term sensing scenario, this protocol improves the network's
performance compared to the existing threshold-based protocol.
In the second half of the thesis, we study two recently emerged
networks, where devices have the ability to: (i) communicate
directly with nearby devices under the control of BSs (i.e.,
device-to-device (D2D) communication), and (ii) harvest radio
frequency energy (i.e., energy harvesting networks). We first
analyze the intra-cell interference in a finite cellular region
underlaid with D2D communication, by incorporating a mode
selection scheme to reduce the interference. We derive the outage
probability at the BS and a D2D receiver, and propose a spectrum
reuse ratio metric to assess the overall D2D communication
performance. We demonstrate that, without impairing the
performance at the BS, if the path-loss exponent on cellular link
is slightly lower than that on D2D link, the spectrum reuse ratio
can have negligible decrease while the average number of
successful D2D transmissions increases with the increasing D2D
node density. This indicates that an increasing level of D2D
communication is beneficial in future networks. Then we study an
ad-hoc network with simultaneous wireless information and power
transfer in an infinite region, where transmitters are wirelessly
charged by power beacons. We formulate the total outage
probability in terms of the power and channel outage
probabilities. The former incorporates a power activation
threshold at transmitters, which is a key practical factor that
has been largely ignored in previous work. We show that, although
increasing power beacon's density or transmit power is not always
beneficial for channel outage probability, it improves the
overall network performance