  The increasing number of connected vehicles in densely populated urban areas
provides an interesting opportunity to counteract the high wireless data
demands in high density and highly mobile scenarios. The idea is to support the
macro base station (BS) with a secondary communication tier composed of a set
of smart and connected vehicles that are in movement in the urban area.
  As a first step towards a comprehensive cost-benefit analysis of this
architecture, this paper considers the case where these vehicles are equipped
with femto-mobile Access Points (fmAPs) and constitute a mobile out-of-band
relay infrastructure. In particular, three techniques to select an fmAP (if
more than one is available) are proposed and the maximal feasible gain in the
packet delivery rate and data rate as a function of the vehicle density,
average vehicle speeds, handoff overhead cost, as well as physical layer
parameters is characterized. The analytical and simulation results provide a
first benchmark characterizing this architecture and the definition of
guidelines for its future realistic study and implementation.
