28-05-2014, 10:50 AM
Location-Based Crowdsourcing for Vehicular Communication in Hybrid Networks
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Abstract
It is a challenge to design efficient routing protocols
for vehicular ad hoc networks (VANETs) because of their highly
dynamic properties. We address the vehicular communication
problem in urban hybrid networks and present a hybrid rout-
ing scheme for data dissemination in VANETs. Location-based
crowdsourcing of nearby roadside units (RSUs) has been applied
to the infrastructural support of inter-vehicle, vehicle-to-roadside,
and inter-roadside communications in hybrid VANETs. The com-
bination of RSU resources and ad hoc networks involves an on-
line probabilistic RSU retrieval algorithm that uses coarse- and
fine-grained localization to estimate the number and location of
available RSUs; a network coding based multicast routing for
dense VANETs using maximum distance separation (MDS) code
and local topology information from the forwarding set to achieve
robust communication and max-flow min-cut data dissemination;
an application of opportunistic routing, using a carry-and-forward
scheme to solve the forwarding disconnection problem in sparse
VANETs; and a routing switch mechanism to guarantee quality of
service (QoS) under various network connectivity and deployment
configurations. The performance of our hybrid routing scheme is
evaluated using both simulations and real testbed experiments.
INTRODUCTION
VEHICULAR ad hoc networks (VANETs) are emerging
new technologies integrating the capabilities of new-
generation wireless networks to achieve mobile data communi-
cations in intelligent transportation systems (ITS) [1]. VANETs
include a variety of ITS applications, e.g., cooperative traffic
monitoring, cooperative driving such as platooning, collision
prevention, nearby information services, content delivery, and
real-time route detour computation. In this paper, two major
applications are implemented in urban VANETs, which can
facilitate the development of cyber–physical transportation sys-
tems [2]: one is retrieval and crowdsourcing [3] of roadside
unit (RSU) resources by vehicle users for wireless access.
Inter-roadside Routing
Once a vehicle retrieves the RSU information and forwards
its data to an available local RSU, the RSU needs to find an
available RSU to form a multihop route to deliver the data to
the destination. If there is an end-to-end inter-roadside route
to the destination, the RSU forwards the data to an RSU that
the destination vehicle associates with the route. Otherwise,
the RSU forwards the data to an RSU that is closest to the
destination vehicle. The RSU receives the data and delivers it to
the local vehicle.
Multicast Routing in HRV
We propose a network coding scheme in multicast rout-
ing, namely HRVmulticast , for data forwarding in VANETs.
HRVmulticast forms the forwarding set to select candidate
vehicles to disseminate data. Network coding is used in the
forwarding set to achieve better capacity and robustness in
VANETs.
Instead of using global topology for the linear network
coding, we get local topology information from forwarding sets
to construct the coding matrix from the source and forward
the coding schemes to the descendant vehicles. A network
generalization of an MDS code is used in multicast network
coding to achieve the max-flow min-cut bound. Meanwhile,
it can minimize the finite field to lower the complexity of the
network coding algorithm.
CONCLUSION
In this paper, we consider the features of hybrid VANETs
with vehicle and RSU supports, and propose holistic hy-
brid routing using location-based crowdsourcing of nearby
RSUs to guarantee communication quality in VANETs. The
probabilistic RSU retrieval algorithm for vehicle-to-roadside
communication, the network coding based multicast routing
in dense VANETs, the opportunistic routing using carry-and-
forward scheme in sparse VANETs, and corresponding routing
switch strategies present a promising solution for reliable data
dissemination and delivery services in hybrid VANETs. Our
simulations and testbed experiments also verify the perfor-
mance of hybrid routing and its possible application in dynamic
vehicular networks.
In the future, we will specifically work on some subprob-
lems of this proposed holistic method. Considering the hybrid
communication networks in urban environments (e.g., Wi-Fi,
WiMax, Long Term Evolution) working on different radio spec-
trums and network standards, we need to design a robust and
seamless handoff strategy for routing switch in urban hybrid
VANETs. Meanwhile, for better location-based crowdsourcing
performance, we have to evaluate more crowd vehicles and
urban environment related factors, and give a geographically
accurate crowdsourcing paradigm for collecting and processing
RSU retrieval results.