3,457 research outputs found
Scaling Laws for Infrastructure Single and Multihop Wireless Networks in Wideband Regimes
With millimeter wave bands emerging as a strong candidate for 5G cellular
networks, next-generation systems may be in a unique position where spectrum is
plentiful. To assess the potential value of this spectrum, this paper derives
scaling laws on the per mobile downlink feasible rate with large bandwidth and
number of nodes, for both Infrastructure Single Hop (ISH) and Infrastructure
Multi-Hop (IMH) architectures. It is shown that, for both cases, there exist
\emph{critical bandwidth scalings} above which increasing the bandwidth no
longer increases the feasible rate per node. These critical thresholds coincide
exactly with the bandwidths where, for each architecture, the network
transitions from being degrees-of-freedom-limited to power-limited. For ISH,
this critical bandwidth threshold is lower than IMH when the number of users
per base station grows with network size. This result suggests that multi-hop
transmissions may be necessary to fully exploit large bandwidth degrees of
freedom in deployments with growing number of users per cell.Comment: 5 pages, 3 figure
Security of 5G-V2X: Technologies, Standardization and Research Directions
Cellular-Vehicle to Everything (C-V2X) aims at resolving issues pertaining to
the traditional usability of Vehicle to Infrastructure (V2I) and Vehicle to
Vehicle (V2V) networking. Specifically, C-V2X lowers the number of entities
involved in vehicular communications and allows the inclusion of
cellular-security solutions to be applied to V2X. For this, the evolvement of
LTE-V2X is revolutionary, but it fails to handle the demands of high
throughput, ultra-high reliability, and ultra-low latency alongside its
security mechanisms. To counter this, 5G-V2X is considered as an integral
solution, which not only resolves the issues related to LTE-V2X but also
provides a function-based network setup. Several reports have been given for
the security of 5G, but none of them primarily focuses on the security of
5G-V2X. This article provides a detailed overview of 5G-V2X with a
security-based comparison to LTE-V2X. A novel Security Reflex Function
(SRF)-based architecture is proposed and several research challenges are
presented related to the security of 5G-V2X. Furthermore, the article lays out
requirements of Ultra-Dense and Ultra-Secure (UD-US) transmissions necessary
for 5G-V2X.Comment: 9 pages, 6 figures, Preprin
Toward End-to-End, Full-Stack 6G Terahertz Networks
Recent evolutions in semiconductors have brought the terahertz band in the
spotlight as an enabler for terabit-per-second communications in 6G networks.
Most of the research so far, however, has focused on understanding the physics
of terahertz devices, circuitry and propagation, and on studying physical layer
solutions. However, integrating this technology in complex mobile networks
requires a proper design of the full communication stack, to address link- and
system-level challenges related to network setup, management, coordination,
energy efficiency, and end-to-end connectivity. This paper provides an overview
of the issues that need to be overcome to introduce the terahertz spectrum in
mobile networks, from a MAC, network and transport layer perspective, with
considerations on the performance of end-to-end data flows on terahertz
connections.Comment: Published on IEEE Communications Magazine, THz Communications: A
Catalyst for the Wireless Future, 7 pages, 6 figure
Network Formation Games Among Relay Stations in Next Generation Wireless Networks
The introduction of relay station (RS) nodes is a key feature in next
generation wireless networks such as 3GPP's long term evolution advanced
(LTE-Advanced), or the forthcoming IEEE 802.16j WiMAX standard. This paper
presents, using game theory, a novel approach for the formation of the tree
architecture that connects the RSs and their serving base station in the
\emph{uplink} of the next generation wireless multi-hop systems. Unlike
existing literature which mainly focused on performance analysis, we propose a
distributed algorithm for studying the \emph{structure} and \emph{dynamics} of
the network. We formulate a network formation game among the RSs whereby each
RS aims to maximize a cross-layer utility function that takes into account the
benefit from cooperative transmission, in terms of reduced bit error rate, and
the costs in terms of the delay due to multi-hop transmission. For forming the
tree structure, a distributed myopic algorithm is devised. Using the proposed
algorithm, each RS can individually select the path that connects it to the BS
through other RSs while optimizing its utility. We show the convergence of the
algorithm into a Nash tree network, and we study how the RSs can adapt the
network's topology to environmental changes such as mobility or the deployment
of new mobile stations. Simulation results show that the proposed algorithm
presents significant gains in terms of average utility per mobile station which
is at least 17.1% better relatively to the case with no RSs and reaches up to
40.3% improvement compared to a nearest neighbor algorithm (for a network with
10 RSs). The results also show that the average number of hops does not exceed
3 even for a network with up to 25 RSs.Comment: IEEE Transactions on Communications, vol. 59, no. 9, pp. 2528-2542,
September 201
Heterogeneous V2V Communications in Multi-Link and Multi-RAT Vehicular Networks
Connected and automated vehicles will enable advanced traffic safety and
efficiency applications thanks to the dynamic exchange of information between
vehicles, and between vehicles and infrastructure nodes. Connected vehicles can
utilize IEEE 802.11p for vehicle-to-vehicle (V2V) and vehicle-to-infrastructure
(V2I) communications. However, a widespread deployment of connected vehicles
and the introduction of connected automated driving applications will notably
increase the bandwidth and scalability requirements of vehicular networks. This
paper proposes to address these challenges through the adoption of
heterogeneous V2V communications in multi-link and multi-RAT vehicular
networks. In particular, the paper proposes the first distributed (and
decentralized) context-aware heterogeneous V2V communications algorithm that is
technology and application agnostic, and that allows each vehicle to
autonomously and dynamically select its communications technology taking into
account its application requirements and the communication context conditions.
This study demonstrates the potential of heterogeneous V2V communications, and
the capability of the proposed algorithm to satisfy the vehicles' application
requirements while approaching the estimated upper bound network capacity
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