90 research outputs found
The Meta Distribution of the SIR in Linear Motorway VANETs
The meta distribution of the signal-to-interference-ratio (SIR) is an
important performance indicator for wireless networks because, for ergodic
point processes, it describes the fraction of scheduled links that achieve
certain reliability, conditionally on the point process. The calculation of the
moments of the meta distribution requires the probability generating functional
(PGFL) of the point process. In vehicular ad hoc networks (VANETs) along
high-speed motorways, the Poisson point process (PPP) is a poor deployment
model, because the drivers, due to the high speeds, maintain large safety
distances. In this paper, we model the distribution of inter-vehicle distance
equal to the sum of a constant hardcore distance and an exponentially
distributed random variable. We design a novel \emph{discretization model} for
the locations of vehicles which can be used to approximate well the PGFL due to
the hardcore point process and the meta distribution of the SIR generated from
synthetic motorway traces. On the other hand, the PPP overestimates
significantly the coefficient-of-variation of the meta distribution due to the
hardcore process, and its predictions fail. In addition, we show that the
calculation of the meta distribution becomes especially meaningful in the upper
tail of the SIR distribution.Comment: to be publishe
Outage in motorway multi-lane VANETs with hardcore headway distance using synthetic traces
In this paper we analyze synthetic mobility traces generated for three-lane
unidirectional motorway traffic to find that the locations of vehicles along a
lane are better modeled by a hardcore point process instead of the
widely-accepted Poisson point process (PPP). In order to capture the repulsion
between successive vehicles while maintaining a level of analytical
tractability, we make a simple extension to PPP: We model the inter-vehicle
distance along a lane equal to the sum of a constant hardcore distance and an
exponentially distributed random variable. We calculate the J-function and the
Ripley's K-function for this hardcore point process. We fit its parameters to
the available traces, and we illustrate that the higher the average speed along
a lane, the more prominent the hardcore component becomes. In addition, we
consider a transmitter-receiver link on the same lane, and we generate simple
formulae for the moments of interference under reduced Palm measure for that
lane, and without conditioning for other lanes. We illustrate that under
Rayleigh fading a shifted-gamma approximation for the distribution of
interference per lane provides a very good fit to the simulated outage
probability using the synthetic traces, while the fit using the PPP is poor.Comment: to be publishe
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