2,392 research outputs found
A Self-Organization Framework for Wireless Ad Hoc Networks as Small Worlds
Motivated by the benefits of small world networks, we propose a
self-organization framework for wireless ad hoc networks. We investigate the
use of directional beamforming for creating long-range short cuts between
nodes. Using simulation results for randomized beamforming as a guideline, we
identify crucial design issues for algorithm design. Our results show that,
while significant path length reduction is achievable, this is accompanied by
the problem of asymmetric paths between nodes. Subsequently, we propose a
distributed algorithm for small world creation that achieves path length
reduction while maintaining connectivity. We define a new centrality measure
that estimates the structural importance of nodes based on traffic flow in the
network, which is used to identify the optimum nodes for beamforming. We show,
using simulations, that this leads to significant reduction in path length
while maintaining connectivity.Comment: Submitted to IEEE Transactions on Vehicular Technolog
The Dynamics of Vehicular Networks in Urban Environments
Vehicular Ad hoc NETworks (VANETs) have emerged as a platform to support
intelligent inter-vehicle communication and improve traffic safety and
performance. The road-constrained, high mobility of vehicles, their unbounded
power source, and the emergence of roadside wireless infrastructures make
VANETs a challenging research topic. A key to the development of protocols for
inter-vehicle communication and services lies in the knowledge of the
topological characteristics of the VANET communication graph. This paper
explores the dynamics of VANETs in urban environments and investigates the
impact of these findings in the design of VANET routing protocols. Using both
real and realistic mobility traces, we study the networking shape of VANETs
under different transmission and market penetration ranges. Given that a number
of RSUs have to be deployed for disseminating information to vehicles in an
urban area, we also study their impact on vehicular connectivity. Through
extensive simulations we investigate the performance of VANET routing protocols
by exploiting the knowledge of VANET graphs analysis.Comment: Revised our testbed with even more realistic mobility traces. Used
the location of real Wi-Fi hotspots to simulate RSUs in our study. Used a
larger, real mobility trace set, from taxis in Shanghai. Examine the
implications of our findings in the design of VANET routing protocols by
implementing in ns-3 two routing protocols (GPCR & VADD). Updated the
bibliography section with new research work
Modeling and Design of Millimeter-Wave Networks for Highway Vehicular Communication
Connected and autonomous vehicles will play a pivotal role in future
Intelligent Transportation Systems (ITSs) and smart cities, in general.
High-speed and low-latency wireless communication links will allow
municipalities to warn vehicles against safety hazards, as well as support
cloud-driving solutions to drastically reduce traffic jams and air pollution.
To achieve these goals, vehicles need to be equipped with a wide range of
sensors generating and exchanging high rate data streams. Recently, millimeter
wave (mmWave) techniques have been introduced as a means of fulfilling such
high data rate requirements. In this paper, we model a highway communication
network and characterize its fundamental link budget metrics. In particular, we
specifically consider a network where vehicles are served by mmWave Base
Stations (BSs) deployed alongside the road. To evaluate our highway network, we
develop a new theoretical model that accounts for a typical scenario where
heavy vehicles (such as buses and lorries) in slow lanes obstruct Line-of-Sight
(LOS) paths of vehicles in fast lanes and, hence, act as blockages. Using tools
from stochastic geometry, we derive approximations for the
Signal-to-Interference-plus-Noise Ratio (SINR) outage probability, as well as
the probability that a user achieves a target communication rate (rate coverage
probability). Our analysis provides new design insights for mmWave highway
communication networks. In considered highway scenarios, we show that reducing
the horizontal beamwidth from to determines a minimal
reduction in the SINR outage probability (namely, at
maximum). Also, unlike bi-dimensional mmWave cellular networks, for small BS
densities (namely, one BS every m) it is still possible to achieve an
SINR outage probability smaller than .Comment: Accepted for publication in IEEE Transactions on Vehicular Technology
-- Connected Vehicles Serie
Spatial networks with wireless applications
Many networks have nodes located in physical space, with links more common
between closely spaced pairs of nodes. For example, the nodes could be wireless
devices and links communication channels in a wireless mesh network. We
describe recent work involving such networks, considering effects due to the
geometry (convex,non-convex, and fractal), node distribution,
distance-dependent link probability, mobility, directivity and interference.Comment: Review article- an amended version with a new title from the origina
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