4,028 research outputs found
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
Enhancing Secrecy with Multi-Antenna Transmission in Wireless Ad Hoc Networks
We study physical-layer security in wireless ad hoc networks and investigate
two types of multi-antenna transmission schemes for providing secrecy
enhancements. To establish secure transmission against malicious eavesdroppers,
we consider the generation of artificial noise with either sectoring or
beamforming. For both approaches, we provide a statistical characterization and
tradeoff analysis of the outage performance of the legitimate communication and
the eavesdropping links. We then investigate the networkwide secrecy throughput
performance of both schemes in terms of the secrecy transmission capacity, and
study the optimal power allocation between the information signal and the
artificial noise. Our analysis indicates that, under transmit power
optimization, the beamforming scheme outperforms the sectoring scheme, except
for the case where the number of transmit antennas are sufficiently large. Our
study also reveals some interesting differences between the optimal power
allocation for the sectoring and beamforming schemes.Comment: to appear in IEEE Transactions on Information Forensics and Securit
Hybrid Satellite-Terrestrial Communication Networks for the Maritime Internet of Things: Key Technologies, Opportunities, and Challenges
With the rapid development of marine activities, there has been an increasing
number of maritime mobile terminals, as well as a growing demand for high-speed
and ultra-reliable maritime communications to keep them connected.
Traditionally, the maritime Internet of Things (IoT) is enabled by maritime
satellites. However, satellites are seriously restricted by their high latency
and relatively low data rate. As an alternative, shore & island-based base
stations (BSs) can be built to extend the coverage of terrestrial networks
using fourth-generation (4G), fifth-generation (5G), and beyond 5G services.
Unmanned aerial vehicles can also be exploited to serve as aerial maritime BSs.
Despite of all these approaches, there are still open issues for an efficient
maritime communication network (MCN). For example, due to the complicated
electromagnetic propagation environment, the limited geometrically available BS
sites, and rigorous service demands from mission-critical applications,
conventional communication and networking theories and methods should be
tailored for maritime scenarios. Towards this end, we provide a survey on the
demand for maritime communications, the state-of-the-art MCNs, and key
technologies for enhancing transmission efficiency, extending network coverage,
and provisioning maritime-specific services. Future challenges in developing an
environment-aware, service-driven, and integrated satellite-air-ground MCN to
be smart enough to utilize external auxiliary information, e.g., sea state and
atmosphere conditions, are also discussed
Context Information for Fast Cell Discovery in mm-wave 5G Networks
The exploitation of the mm-wave bands is one of the most promising solutions
for 5G mobile radio networks. However, the use of mm-wave technologies in
cellular networks is not straightforward due to mm-wave harsh propagation
conditions that limit access availability. In order to overcome this obstacle,
hybrid network architectures are being considered where mm-wave small cells can
exploit an overlay coverage layer based on legacy technology. The additional
mm-wave layer can also take advantage of a functional split between control and
user plane, that allows to delegate most of the signaling functions to legacy
base stations and to gather context information from users for resource
optimization. However, mm-wave technology requires high gain antenna systems to
compensate for high path loss and limited power, e.g., through the use of
multiple antennas for high directivity. Directional transmissions must be also
used for the cell discovery and synchronization process, and this can lead to a
non-negligible delay due to the need to scan the cell area with multiple
transmissions at different directions. In this paper, we propose to exploit the
context information related to user position, provided by the separated control
plane, to improve the cell discovery procedure and minimize delay. We
investigate the fundamental trade-offs of the cell discovery process with
directional antennas and the effects of the context information accuracy on its
performance. Numerical results are provided to validate our observations.Comment: 6 pages, 8 figures, in Proceedings of European Wireless 201
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