20 research outputs found
A multi-objective approach to indoor wireless heterogeneous networks planning
We present a multi-objective optimization approach for indoor wireless network planning subject to constraints for exposure minimization, coverage maximization and power consumption minimization. We consider heterogeneous networks consisting of WiFi Access Points (APs) and Long Term Evolution (LTE) femtocells. We propose a design framework based on Multi-objective Biogeography-based Optimization (MOBBO). The results of the proposed method indicate the advantages and applicability of the multi-objective approach
Distribution of Cell Area in Bounded Poisson Voronoi Tessellations with Application to Secure Local Connectivity
Poisson Voronoi tessellations have been used in modeling many types of
systems across different sciences, from geography and astronomy to
telecommunications. The existing literature on the statistical properties of
Poisson Voronoi cells is vast, however, little is known about the properties of
Voronoi cells located close to the boundaries of a compact domain. In a domain
with boundaries, some Voronoi cells would be naturally clipped by the boundary,
and the cell area falling inside the deployment domain would have different
statistical properties as compared to those of non-clipped Voronoi cells
located in the bulk of the domain. In this paper, we consider the planar
Voronoi tessellation induced by a homogeneous Poisson point process of
intensity in a quadrant, where the two half-axes represent
boundaries. We show that the mean cell area is less than when
the seed is located exactly at the boundary, and it can be larger than
when the seed lies close to the boundary. In addition, we
calculate the second moment of cell area at two locations for the seed: (i) at
the corner of a quadrant, and (ii) at the boundary of the half-plane. We
illustrate that the two-parameter Gamma distribution, with location-dependent
parameters calculated using the method of moments, can be of use in
approximating the distribution of cell area. As a potential application, we use
the Gamma approximations to study the degree distribution for secure
connectivity in wireless sensor networks deployed over a domain with
boundaries.Comment: to be publishe
Cost-Effective Cache Deployment in Mobile Heterogeneous Networks
This paper investigates one of the fundamental issues in cache-enabled
heterogeneous networks (HetNets): how many cache instances should be deployed
at different base stations, in order to provide guaranteed service in a
cost-effective manner. Specifically, we consider two-tier HetNets with
hierarchical caching, where the most popular files are cached at small cell
base stations (SBSs) while the less popular ones are cached at macro base
stations (MBSs). For a given network cache deployment budget, the cache sizes
for MBSs and SBSs are optimized to maximize network capacity while satisfying
the file transmission rate requirements. As cache sizes of MBSs and SBSs affect
the traffic load distribution, inter-tier traffic steering is also employed for
load balancing. Based on stochastic geometry analysis, the optimal cache sizes
for MBSs and SBSs are obtained, which are threshold-based with respect to cache
budget in the networks constrained by SBS backhauls. Simulation results are
provided to evaluate the proposed schemes and demonstrate the applications in
cost-effective network deployment
Downlink Coverage and Rate Analysis of Low Earth Orbit Satellite Constellations Using Stochastic Geometry
As low Earth orbit (LEO) satellite communication systems are gaining
increasing popularity, new theoretical methodologies are required to
investigate such networks' performance at large. This is because deterministic
and location-based models that have previously been applied to analyze
satellite systems are typically restricted to support simulations only. In this
paper, we derive analytical expressions for the downlink coverage probability
and average data rate of generic LEO networks, regardless of the actual
satellites' locality and their service area geometry. Our solution stems from
stochastic geometry, which abstracts the generic networks into uniform binomial
point processes. Applying the proposed model, we then study the performance of
the networks as a function of key constellation design parameters. Finally, to
fit the theoretical modeling more precisely to real deterministic
constellations, we introduce the effective number of satellites as a parameter
to compensate for the practical uneven distribution of satellites on different
latitudes. In addition to deriving exact network performance metrics, the study
reveals several guidelines for selecting the design parameters for future
massive LEO constellations, e.g., the number of frequency channels and
altitude.Comment: Accepted for publication in the IEEE Transactions on Communications
in April 202