15,184 research outputs found
Fine-Grained Reliability for V2V Communications around Suburban and Urban Intersections
Safe transportation is a key use-case of the 5G/LTE Rel.15+ communications,
where an end-to-end reliability of 0.99999 is expected for a vehicle-to-vehicle
(V2V) transmission distance of 100-200 m. Since communications reliability is
related to road-safety, it is crucial to verify the fulfillment of the
performance, especially for accident-prone areas such as intersections. We
derive closed-form expressions for the V2V transmission reliability near
suburban corners and urban intersections over finite interference regions. The
analysis is based on plausible street configurations, traffic scenarios, and
empirically-supported channel propagation. We show the means by which the
performance metric can serve as a preliminary design tool to meet a target
reliability. We then apply meta distribution concepts to provide a careful
dissection of V2V communications reliability. Contrary to existing work on
infinite roads, when we consider finite road segments for practical deployment,
fine-grained reliability per realization exhibits bimodal behavior. Either
performance for a certain vehicular traffic scenario is very reliable or
extremely unreliable, but nowhere in relatively proximity to the average
performance. In other words, standard SINR-based average performance metrics
are analytically accurate but can be insufficient from a practical viewpoint.
Investigating other safety-critical point process networks at the meta
distribution-level may reveal similar discrepancies.Comment: 27 pages, 6 figures, submitted to IEEE Transactions on Wireless
Communication
Limits on the Capacity of In-Band Full Duplex Communication in Uplink Cellular Networks
Simultaneous co-channel transmission and reception, denoted as in-band full
duplex (FD) communication, has been promoted as an attractive solution to
improve the spectral efficiency of cellular networks. However, in addition to
the self-interference problem, cross-mode interference (i.e., between uplink
and downlink) imposes a major obstacle for the deployment of FD communication
in cellular networks. More specifically, the downlink to uplink interference
represents the performance bottleneck for FD operation due to the uplink
limited transmission power and venerable operation when compared to the
downlink counterpart. While the positive impact of FD communication to the
downlink performance has been proved in the literature, its effect on the
uplink transmission has been neglected. This paper focuses on the effect of
downlink interference on the uplink transmission in FD cellular networks in
order to see whether FD communication is beneficial for the uplink transmission
or not, and if yes for which type of network. To quantify the expected
performance gains, we derive a closed form expression of the maximum achievable
uplink capacity in FD cellular networks. In contrast to the downlink capacity
which always improves with FD communication, our results show that the uplink
performance may improve or degrade depending on the associated network
parameters. Particularly, we show that the intensity of base stations (BSs) has
a more prominent effect on the uplink performance than their transmission
power
A Survey of Air-to-Ground Propagation Channel Modeling for Unmanned Aerial Vehicles
In recent years, there has been a dramatic increase in the use of unmanned
aerial vehicles (UAVs), particularly for small UAVs, due to their affordable
prices, ease of availability, and ease of operability. Existing and future
applications of UAVs include remote surveillance and monitoring, relief
operations, package delivery, and communication backhaul infrastructure.
Additionally, UAVs are envisioned as an important component of 5G wireless
technology and beyond. The unique application scenarios for UAVs necessitate
accurate air-to-ground (AG) propagation channel models for designing and
evaluating UAV communication links for control/non-payload as well as payload
data transmissions. These AG propagation models have not been investigated in
detail when compared to terrestrial propagation models. In this paper, a
comprehensive survey is provided on available AG channel measurement campaigns,
large and small scale fading channel models, their limitations, and future
research directions for UAV communication scenarios
Analytical Model for Outdoor Millimeter Wave Channels using Geometry-Based Stochastic Approach
The severe bandwidth shortage in conventional microwave bands has spurred the
exploration of the millimeter wave (MMW) spectrum for the next revolution in
wireless communications. However, there is still lack of proper channel
modeling for the MMW wireless propagation, especially in the case of outdoor
environments. In this paper, we develop a geometry-based stochastic channel
model to statistically characterize the effect of all the first-order
reflection paths between the transmitter and receiver. These first-order
reflections are generated by the single-bounce of signals reflected from the
walls of randomly distributed buildings. Based on this geometric model, a
closed-form expression for the power delay profile (PDP) contributed by all the
first-order reflection paths is obtained and then used to evaluate their impact
on the MMW outdoor propagation characteristics. Numerical results are provided
to validate the accuracy of the proposed model under various channel parameter
settings. The findings in this paper provide a promising step towards more
complex and practical MMW propagation channel modeling.Comment: Accepted to appear in IEEE Transactions on Vehicular Technolog
Fine-Grained vs. Average Reliability for V2V Communications around Intersections
Intersections are critical areas of the transportation infrastructure
associated with 47% of all road accidents. Vehicle-to-vehicle (V2V)
communication has the potential of preventing up to 35% of such serious road
collisions. In fact, under the 5G/LTE Rel.15+ standardization, V2V is a
critical use-case not only for the purpose of enhancing road safety, but also
for enabling traffic efficiency in modern smart cities. Under this anticipated
5G definition, high reliability of 0.99999 is expected for semi-autonomous
vehicles (i.e., driver-in-the-loop). As a consequence, there is a need to
assess the reliability, especially for accident-prone areas, such as
intersections. We unpack traditional average V2V reliability in order to
quantify its related fine-grained V2V reliability. Contrary to existing work on
infinitely large roads, when we consider finite road segments of significance
to practical real-world deployment, fine-grained reliability exhibits bimodal
behavior. Performance for a certain vehicular traffic scenario is either very
reliable or extremely unreliable, but nowhere in relative proximity to the
average performance.Comment: 5 pages, 4 figures. arXiv admin note: substantial text overlap with
arXiv:1706.1001
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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